Effect of solids concentration on removal of heavy metals from mine tailings via bioleaching

International Nuclear Information System (INIS)

Liu Yunguo; Zhou Ming; Zeng Guangming; Li Xin; Xu Weihua; Fan Ting

2007-01-01

Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The objective of this work is to demonstrate the feasibility to remove heavy metals from mine tailings with the use of bioleaching and meanwhile to investigate the effect of solids concentration on removal of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria and the transformation of heavy metal forms after the bioleaching process. This work showed the laboratory results of bioleaching experiments on Pb-Zn-Cu mine tailings. The results showed that 98.08% Zn, 96.44% Cu, and 43.52% Pb could be removed from mine tailings by the bioleaching experiment after 13 days at 1% (w/v) solids concentration and the rates of pH reduction, ORP rise and sulfate production were reduced with the increase of solids concentration, due to the buffering capacity of mine tailing solids. The results also indicated that solid concentration 1% was found to be best to bacterial activity and metal solubilization of the five solids concentration tested (1%, 2%, 5%, 8% and 10%) under the chosen experimental conditions. In addition, the bioleaching had a significant impact on changes in partitioning of heavy metals

Effect of solids concentration on removal of heavy metals from mine tailings via bioleaching

Energy Technology Data Exchange (ETDEWEB)

Liu Yunguo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China)]. E-mail: axore@163.com; Zhou Ming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Zeng Guangming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Li Xin [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Xu Weihua [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Fan Ting [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China)

2007-03-06

Mining of mineral ore and disposal of resulting waste tailings pose a significant risk to the surrounding environment. The objective of this work is to demonstrate the feasibility to remove heavy metals from mine tailings with the use of bioleaching and meanwhile to investigate the effect of solids concentration on removal of heavy metals from mine tailings by indigenous sulfur-oxidizing bacteria and the transformation of heavy metal forms after the bioleaching process. This work showed the laboratory results of bioleaching experiments on Pb-Zn-Cu mine tailings. The results showed that 98.08% Zn, 96.44% Cu, and 43.52% Pb could be removed from mine tailings by the bioleaching experiment after 13 days at 1% (w/v) solids concentration and the rates of pH reduction, ORP rise and sulfate production were reduced with the increase of solids concentration, due to the buffering capacity of mine tailing solids. The results also indicated that solid concentration 1% was found to be best to bacterial activity and metal solubilization of the five solids concentration tested (1%, 2%, 5%, 8% and 10%) under the chosen experimental conditions. In addition, the bioleaching had a significant impact on changes in partitioning of heavy metals.

Investigation of the dye concentration influence on the lasing wavelength and threshold for a micro-fluidic dye laser

DEFF Research Database (Denmark)

Helbo, Bjarne; Kragh, Søren; Kjeldsen, B.G.

2003-01-01

We investigate a micro-fluidic dye laser, which can be integrated with polymer-based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the lasing threshold. The laser device is characterised using the laser dye Rhodamine 6G dissolved...... in ethanol, and the influence of dye concentration on the lasing wavelength and threshold is investigated. The experiments confirm the predictions of the rate-equation model, that lasing can be achieved in the 10 mum long laser cavity with moderate concentrations of Rhodamine 6G in ethanol, starting from 5 x...

Feasibility of using acoustic velocity meters for estimating highly organic suspended-solids concentrations in streams

Science.gov (United States)

Patino, Eduardo

1996-01-01

A field experiment was conducted at the Levee 4 canal site below control structure G-88 in the Everglades agricultural area in northwestern Broward County, Florida, to study the relation of acoustic attenuation to suspended-solids concentrations. Acoustic velocity meter and temperature data were obtained with concurrent water samples analyzed for suspended-solids concentrations. Two separate acoustic velocity meter frequencies were used, 200 and 500 kilohertz, to determine the sensitivity of acoustic attenuation to frequency for the measured suspended-solids concentration range. Suspended-solids concentrations for water samples collected at the Levee 4 canal site from July 1993 to September 1994 ranged from 22 to 1,058 milligrams per liter, and organic content ranged from about 30 to 93 percent. Regression analyses showed that attenuation data from the acoustic velocity meter (automatic gain control) and temperature data alone do not provide enough information to adequately describe the concentrations of suspended solids. However, if velocity is also included as one of the independent variables in the regression model, a satisfactory correlation can be obtained. Thus, it is feasible to use acoustic velocity meter instrumentation to estimate suspended-solids concentrations in streams, even when suspended solids are primarily composed of organic material. Using the most comprehensive data set available for the study (500 kiloherz data), the best fit regression model produces a standard error of 69.7 milligrams per liter, with actual errors ranging from 2 to 128 milligrams per liter. Both acoustic velocity meter transmission frequencies of 200 and 500 hilohertz produced similar results, suggesting that transducers of either frequency could be used to collect attenuation data at the study site. Results indicate that calibration will be required for each acoustic velocity meter system to the unique suspended-solids regime existing at each site. More robust solutions may

About Error in Measuring Oxygen Concentration by Solid-Electrolyte Sensors

Directory of Open Access Journals (Sweden)

V. I. Nazarov

2008-01-01

Full Text Available The paper evaluates additional errors while measuring oxygen concentration in a gas mixture by a solid-electrolyte cell. Experimental dependences of additional errors caused by changes in temperature in a sensor zone, discharge of gas mixture supplied to a sensor zone, partial pressure in the gas mixture and fluctuations in oxygen concentrations in the air.

Concentration Impedance in Testing of Solid Oxide Cells Revisited

DEFF Research Database (Denmark)

Mogensen, Mogens Bjerg; Ebbesen, Sune Dalgaard; Jensen, Søren Højgaard

2017-01-01

The concentration impedance originating from diffusion and reactant conversion impedance of the Ni-YSZ supported fuel electrode in solid oxide cell has been treated many times during the latest couple of decades. In spite of this, the separation of the diffusion impedance from the conversion...

Quantitative cross-sectional measurement of solid concentration distribution in slurries using a wire-mesh sensor

International Nuclear Information System (INIS)

Dos Santos, Eduardo Nunes; Da Silva, Marco Jose; Schleicher, Eckhard; Reinecke, Sebastian; Hampel, Uwe

2016-01-01

Wire-mesh sensors have so far been widely applied in gas–liquid flows where resistance or capacitance distributions are measured and converted into gas or liquid holdup distributions. In this work we report on the qualification of the wire-mesh imaging technique for the measurement of cross-sectional solid concentrations in solid–liquid mixtures. As the dielectric constants of solid particles are different from those of gas, water or oil in the flow, measuring this property can be used as an indication of solid distribution. Experiments were performed in a stirred tank of 100 mm diameter equipped with a capacitance wire-mesh sensor. The wire-mesh sensor was operated at an acquisition speed of 4000 frames per second and has a spatial resolution of 6.25 mm. As solids we used silica sand particles (diameter ∼250 μm) which were suspended in water in a volume concentration range of 1% to 35% to form slurries. By varying the stirring speed, different solid concentration distributions were produced and investigated. In order to convert the measured relative permittivity distribution into a solid concentration distribution, an empirical approach was employed. (paper)

Proposal of threshold levels for the definition of non-radioactive wastes

International Nuclear Information System (INIS)

Yoshida, Yoshikazu

1979-01-01

With increasing amounts of radioactive wastes along with the advances of nuclear power generation and radioactive material utilizations, the needs for management cost reduction and resource saving have arisen. Under the situation, the threshold levels for the definition of non-radioactive solid wastes are required. The problem has been studied by an ad hoc committee in Nuclear Safety Research Association, by the request of the Science and Technology Agency. The matters described are the procedures of deriving the threshold levels, the feasibility studies of the management of waste threshold-level with several enterprises, and future subjects of study. The threshold levels are grouped in two, i.e. the unconditional level and the conditional level. According to the unconditional threshold level, solid wastes are separated definitely into radioactive and non-radioactive ones. According to the conditional threshold level, under certain conditions, some radioactive solid wastes according to the unconditional level are regarded as non-radioactive ones. (J.P.N.)

A threshold concentration of anti-merozoite antibodies is required for protection from clinical episodes of malaria

DEFF Research Database (Denmark)

Murungi, Linda M; Kamuyu, Gathoni; Lowe, Brett

2013-01-01

Antibodies to selected Plasmodium falciparum merozoite antigens are often reported to be associated with protection from malaria in one epidemiological cohort, but not in another. Here, we sought to understand this paradox by exploring the hypothesis that a threshold concentration of antibodies i...

MFT homogeneity study at TNX: Final report on the low weight percent solids concentration

International Nuclear Information System (INIS)

Jenkins, W.J.

1993-01-01

A statistical design and analysis of both elemental analyses and weight percent solids analyses data was utilized to evaluate the MFT homogeneity at low heel levels and low agitator speed at both high and low solids feed concentrations. The homogeneity was also evaluated at both low and high agitator speed at the 6000+ gallons static level. The dynamic level portion of the test simulated feeding the Melter from the MFT to evaluate the uniformity of the solids slurry composition (Frit-PHA-Sludge) entering the melter from the MFT. This final report provides the results and conclusions from the second half of the study, the low weight percent solids concentration portion, as well as a comparison with the results from the first half of the study, the high weight percent solids portion

Effects of Spray-Drying and Choice of Solid Carriers on Concentrations of Labrasol® and Transcutol® in Solid Self-Microemulsifying Drug Delivery Systems (SMEDDS

Directory of Open Access Journals (Sweden)

Christopher Wai-Kei Lam

2013-01-01

Full Text Available Solid self-microemulsifying drug delivery systems (SMEDDS have been used increasingly for improving the bioavailability of hydrophobic drugs. Labrasol® and Transcutol® are used widely as surfactant and solubilizer in the formulation of solid SMEDDS. We investigated the effects of spray-drying and the use of different solid carriers on concentrations of Labrasol® and Transcutol® in solid SMEDDS with scutellarin as the formulated drug. Liquid and gas chromatography tandem mass spectrometry (LC-MS and GC-MS methods were developed for measuring low concentrations of Labrasol® and Transcutol®. In the preparation of solid SMEDDS, lactose, hydroxypropylmethyl cellulose (HPMC and microcrystalline cellulose (MCC were used as solid carriers. Judging from the retention ratios of Labrasol® and Transcutol®, the droplet size of solid SMEDDS increased after spray-drying of liquid SMEDDS, and concentrations of these excipients decreased after the solidifying procedure. In such reduction, Lactose and HPMC were found to preserve Labrasol® and Transcutol® better than MCC during spray-drying, and the resultant droplet sizes were smaller than that of MCC. Labrasol® and Transcutol® showed good thermal stability at 60 °C degree for 10 days. It can be concluded that spray-drying could increase the droplet size of solid SMEDDS and decreased the concentration of Labrasol® and Transcutol® therein, while water-soluble solid carriers could preserve Labrasol® and Transcutol® better than insoluble carriers in the solid SMEDDS.

Determination of negligible concentration threshold values for water pollution assessment; Ableitung von Geringfuegigkeitsschwellen zur Beurteilung von Grundwasserverunreinigungen

Energy Technology Data Exchange (ETDEWEB)

Trenck, K.T. von der [Landesanstalt fuer Umweltschutz Baden-Wuerttemberg, Karlsruhe (Germany); Roeder, R.; Slama, H. [Bayerisches Landesamt fuer Wasserwirtschaft, Muenchen (Germany); Markard, C.; Kuehl, C. [Umweltbundesamt, Berlin (Germany)

1999-06-01

The contribution summarizes the major aspects of results and proposals elaborated by a working group: Criteria for derivation of the negligible concentration threshold, and proposed threshold values for organic and inorganic substances dangerous to water. Evaluation criteria are explained for assessing human toxicity as well as ecotoxicity, and substance-specific evaluation criteria are listed. (orig./CB) [Deutsch] Hauptpunkte des Beitrags, der die Ergebnisse eines Arbeitskreises erlaeutert, sind: Ableitungskriterien fr die Geringfuegigkeitsschwelle und Vorschlag von Geringfuegigkeitsschwellen fr organische und anorganische Wasserschadstoffe. Darstellung der humantoxischen Bewertungskriterien, sowie oekotoxische Bewertungskriterien. Zusammenstellung der stoffspezifischen Bewertungskriterien. (orig./AJ)

Automated Analysis of Human Sperm Number and Concentration (Oligospermia) Using Otsu Threshold Method and Labelling

Science.gov (United States)

Susrama, I. G.; Purnama, K. E.; Purnomo, M. H.

2016-01-01

Oligospermia is a male fertility issue defined as a low sperm concentration in the ejaculate. Normally the sperm concentration is 20-120 million/ml, while Oligospermia patients has sperm concentration less than 20 million/ml. Sperm test done in the fertility laboratory to determine oligospermia by checking fresh sperm according to WHO standards in 2010 [9]. The sperm seen in a microscope using a Neubauer improved counting chamber and manually count the number of sperm. In order to be counted automatically, this research made an automation system to analyse and count the sperm concentration called Automated Analysis of Sperm Concentration Counters (A2SC2) using Otsu threshold segmentation process and morphology. Data sperm used is the fresh sperm directly in the analysis in the laboratory from 10 people. The test results using A2SC2 method obtained an accuracy of 91%. Thus in this study, A2SC2 can be used to calculate the amount and concentration of sperm automatically

Dissolved-solids sources, loads, yields, and concentrations in streams of the conterminous United States

Science.gov (United States)

Anning, David W.; Flynn, Marilyn E.

2014-01-01

Recent studies have shown that excessive dissolved-solids concentrations in water can have adverse effects on the environment and on agricultural, domestic, municipal, and industrial water users. Such effects motivated the U.S. Geological Survey’s National Water Quality Assessment Program to develop a SPAtially-Referenced Regression on Watershed Attributes (SPARROW) model that has improved the understanding of sources, loads, yields, and concentrations of dissolved solids in streams of the conterminous United States.

Application of Acoustic and Optic Methods for Estimating Suspended-Solids Concentrations in the St. Lucie River Estuary, Florida

Science.gov (United States)

Patino, Eduardo; Byrne, Michael J.

2004-01-01

Acoustic and optic methods were applied to estimate suspended-solids concentrations in the St. Lucie River Estuary, southeastern Florida. Acoustic Doppler velocity meters were installed at the North Fork, Speedy Point, and Steele Point sites within the estuary. These sites provide varying flow, salinity, water-quality, and channel cross-sectional characteristics. The monitoring site at Steele Point was not used in the analyses because repeated instrument relocations (due to bridge construction) prevented a sufficient number of samples from being collected at the various locations. Acoustic and optic instruments were installed to collect water velocity, acoustic backscatter strength (ABS), and turbidity data that were used to assess the feasibility of estimating suspended-solids concentrations in the estuary. Other data collected at the monitoring sites include tidal stage, salinity, temperature, and periodic discharge measurements. Regression analyses were used to determine the relations of suspended-solids concentration to ABS and suspended-solids concentration to turbidity at the North Fork and Speedy Point sites. For samples used in regression analyses, measured suspended-solids concentrations at the North Fork and Speedy Point sites ranged from 3 to 37 milligrams per liter, and organic content ranged from 50 to 83 percent. Corresponding salinity for these samples ranged from 0.12 to 22.7 parts per thousand, and corresponding temperature ranged from 19.4 to 31.8 ?C. Relations determined using this technique are site specific and only describe suspended-solids concentrations at locations where data were collected. The suspended-solids concentration to ABS relation resulted in correlation coefficients of 0.78 and 0.63 at the North Fork and Speedy Point sites, respectively. The suspended-solids concentration to turbidity relation resulted in correlation coefficients of 0.73 and 0.89 at the North Fork and Speedy Point sites, respectively. The adequacy of the

Threshold guidance update

International Nuclear Information System (INIS)

Wickham, L.E.

1986-01-01

The Department of Energy (DOE) is developing the concept of threshold quantities for use in determining which waste materials must be handled as radioactive waste and which may be disposed of as nonradioactive waste at its sites. Waste above this concentration level would be managed as radioactive or mixed waste (if hazardous chemicals are present); waste below this level would be handled as sanitary waste. Last years' activities (1984) included the development of a threshold guidance dose, the development of threshold concentrations corresponding to the guidance dose, the development of supporting documentation, review by a technical peer review committee, and review by the DOE community. As a result of the comments, areas have been identified for more extensive analysis, including an alternative basis for selection of the guidance dose and the development of quality assurance guidelines. Development of quality assurance guidelines will provide a reasonable basis for determining that a given waste stream qualifies as a threshold waste stream and can then be the basis for a more extensive cost-benefit analysis. The threshold guidance and supporting documentation will be revised, based on the comments received. The revised documents will be provided to DOE by early November. DOE-HQ has indicated that the revised documents will be available for review by DOE field offices and their contractors

Gravitational settling of a highly concentrated system of solid spherical particles

Science.gov (United States)

Arkhipov, V. A.; Usanina, A. S.

2017-09-01

In the present paper, we report on the results of an experimental study of the process of gravity sedimentation of a cloud of monodispersed solid spherical particles with initial volume concentration C > 0.03, which was performed in a wide range of Reynolds numbers. An analytical estimate of the settling regimes of spherical particle clouds is presented. A new method for creating a spherical particle cloud with a high concentration of particles is proposed. A qualitative picture of the settling process of a highly concentrated particle cloud under gravity is revealed. A criterial dependence for the drag coefficient of a sedimenting spherical particle cloud as an entity is obtained.

Sorption of Arsenic from Desalination Concentrate onto Drinking Water Treatment Solids: Operating Conditions and Kinetics

Directory of Open Access Journals (Sweden)

Xuesong Xu

2018-01-01

Full Text Available Selective removal of arsenic from aqueous solutions with high salinity is required for safe disposal of the concentrate and protection of the environment. The use of drinking water treatment solids (DWTS to remove arsenic from reverse osmosis (RO concentrate was studied by batch sorption experiments. The impacts of solution chemistry, contact time, sorbent dosage, and arsenic concentration on sorption were investigated, and arsenic sorption kinetics and isotherms were modeled. The results indicated that DWTS were effective in removing arsenic from RO concentrate. The arsenic sorption process followed a pseudo-second-order kinetic model. Multilayer adsorption was simulated by Freundlich equation. The maximum sorption capacities were calculated to be 170 mg arsenic per gram of DWTS. Arsenic sorption was enhanced by surface precipitation onto the DWTS due to the high amount of calcium in the RO concentrate and the formation of ternary complexes between arsenic and natural organic matter (NOM bound by the polyvalent cations in DWTS. The interactions between arsenic and NOM in the solid phase and aqueous phase exhibited two-sided effects on arsenic sorption onto DWTS. NOM in aqueous solution hindered the arsenic sorption onto DWTS, while the high organic matter content in solid DWTS phase enhanced arsenic sorption.

Approach to DOE threshold guidance limits

International Nuclear Information System (INIS)

Shuman, R.D.; Wickham, L.E.

1984-01-01

The need for less restrictive criteria governing disposal of extremely low-level radioactive waste has long been recognized. The Low-Level Waste Management Program has been directed by the Department of Energy (DOE) to aid in the development of a threshold guidance limit for DOE low-level waste facilities. Project objectives are concernd with the definition of a threshold limit dose and pathway analysis of radionuclide transport within selected exposure scenarios at DOE sites. Results of the pathway analysis will be used to determine waste radionuclide concentration guidelines that meet the defined threshold limit dose. Methods of measurement and verification of concentration limits round out the project's goals. Work on defining a threshold limit dose is nearing completion. Pathway analysis of sanitary landfill operations at the Savannah River Plant and the Idaho National Engineering Laboratory is in progress using the DOSTOMAN computer code. Concentration limit calculations and determination of implementation procedures shall follow completion of the pathways work. 4 references

Tunable femtosecond lasers with low pump thresholds

Science.gov (United States)

Oppo, Karen

The work in this thesis is concerned with the development of tunable, femtosecond laser systems, exhibiting low pump threshold powers. The main motive for this work was the development of a low threshold, self-modelocked Ti:Al2O3 laser in order to replace the conventional large-frame argon-ion pump laser with a more compact and efficient all-solid-state alternative. Results are also presented for an all-solid-state, self-modelocked Cr:LiSAF laser, however most of this work is concerned with self-modelocked Ti:Al2O3 laser systems. In chapter 2, the operation of a regeneratively-initiated, and a hard-aperture self- modelocked Ti:Al2O3 laser, pumped by an argon-ion laser, is discussed. Continuous- wave oscillation thresholds as low as 160mW have been demonstrated, along with self-modelocked threshold powers as low as 500mW. The measurement and suppression of phase noise on modelocked lasers is discussed in chapter 3. This is followed by a comparison of the phase noise characteristics of the regeneratively-initiated, and hard-aperture self-modelocked Ti:Al2O3 lasers. The use of a synchronously-operating, high resolution electron-optical streak camera in the evaluation of timing jitter is also presented. In chapter 4, the construction and self-modelocked operation of an all-solid-state Ti:Al2O3 laser is described. The all-solid-state alternative to the conventional argon-ion pump laser was a continuous-wave, intracavity-frequency doubled, diode-laser pumped Nd:YLF ring laser. At a total diode-laser pump power of 10W, this minilaser was capable of producing a single frequency output of 1W, at 523.5nm in a TEM00 beam. The remainder of this thesis looks at the operation of a self-modelocked Ti:Al2O3 laser generating ultrashort pulses at wavelengths as long as 1053nm. The motive for this work was the development of an all-solid-state, self- modelocked Ti:Al2O3 laser operating at 1053nm, for use as a master oscillator in a Nd:glass power chain.

Relationships Between Land Use and Stream Nutrient Concentrations in a Highly Urbanized Tropical Region of Brazil: Thresholds and Riparian Zones.

Science.gov (United States)

Tromboni, F; Dodds, W K

2017-07-01

Nutrient enrichment in streams due to land use is increasing globally, reducing water quality and causing eutrophication of downstream fresh and coastal waters. In temperate developed countries, the intensive use of fertilizers in agriculture is a main driver of increasing nutrient concentrations, but high levels and fast rates of urbanization can be a predominant issue in some areas of the developing world. We investigated land use in the highly urbanized tropical State of Rio de Janeiro, Brazil. We collected total nitrogen, total phosphorus, and inorganic nutrient data from 35 independent watersheds distributed across the State and characterized land use at a riparian and entire watershed scales upstream from each sample station, using ArcGIS. We used regression models to explain land use influences on nutrient concentrations and to assess riparian protection relationships to water quality. We found that urban land use was the primary driver of nutrient concentration increases, independent of the scale of analyses and that urban land use was more concentrated in the riparian buffer of streams than in the entire watersheds. We also found significant thresholds that indicated strong increases in nutrient concentrations with modest increases in urbanization reaching maximum nutrient concentrations between 10 and 46% urban cover. These thresholds influenced calculation of reference nutrient concentrations, and ignoring them led to higher estimates of these concentrations. Lack of sewage treatment in concert with urban development in riparian zones apparently leads to the observation that modest increases in urban land use can cause large increases in nutrient concentrations.

Implications of Industrial Processing Strategy on Cellulosic Ethanol Production at High Solids Concentrations

DEFF Research Database (Denmark)

Cannella, David

The production of cellulosic ethanol is a biochemical process of not edible biomasses which contain the cellulose. The process involves the use of enzymes to hydrolyze the cellulose in fermentable sugars to finally produce ethanol via fermentative microorganisms (i.e. yeasts). These biomasses...... are the leftover of agricultural productions (straws), not edible crops (giant reed) or wood, thus the ethanol so produced is also called second generation (or 2G ethanol), which differs from the first generation produced from starch (sugar beets mostly). In the industrial production of cellulosic ethanol high...... solids strategy resulted critical for its cost effectiveness: high concentration of initial biomass it will lead to high concentration of the final product (ethanol), thus more convenient to isolate. This thesis investigate the implementation of a high solids loading concept into cellulosic ethanol...

Characteristic of total suspended particulate (TSP) containing Pb and Zn at solid waste landfill

Science.gov (United States)

Budihardjo, M. A.; Noveandra, K.; Samadikun, B. P.

2018-05-01

Activities conducted at municipal solid waste landfills (MSWLs) potentially cause air pollution. Heavy vehicles in MSWLs release various pollutants that can have negative impacts for humans. One noticeable pollutant at MSWLs is airborne total suspended particulate (TSP) which may contain heavy metals such as Pb and Zn and can cause disease when inhaled by humans. In this study, TSP from a landfill in Semarang, Indonesia was collected and characterized to quantify the concentration of Pb and Zn. Meteorological factors (i.e. temperature, humidity and wind velocity) and landfill activities were considered as factors affecting pollutant concentrations. TSP was sampled using dust samplers while the concentrations of heavy metals in TSP were analyzed using an Atomic Absorption Spectrophotometer (AAS). Pb concentration ranged from 0.84 to 1.78 µg/m3 while Zn concentration was from 7.87 to 8.76 µg/m3. The levels of Pb were below the threshold specified by the Indonesian Government. Meanwhile, the threshold for Zn has not yet been determined.

Inhibitory effect of high NH4(+)-N concentration on anaerobic biotreatment of fresh leachate from a municipal solid waste incineration plant.

Science.gov (United States)

Liu, Zhao; Dang, Yan; Li, Caihua; Sun, Dezhi

2015-09-01

Fresh leachate from municipal solid waste (MSW) incineration plants generally contains extremely high NH4(+)-N concentration which could inhibit the bioactivity of microorganisms. The inhibitory effect of high NH4(+)-N concentration on anaerobic biotreatment of fresh leachate from a MSW incineration plant in China has been investigated in this study. The inhibition processes was studied by both static tests and a laboratory-scale expanded granular sludge bed (EGSB) reactor. The specific methanogenic activity (SMA) of the microorganisms in anaerobic granular sludge was inhibited with the NH4(+)-N concentration increasing to 1000mg/L in static tests. As well the chemical oxygen demand (COD) removal efficiency and the methane yield decreased in the EGSB reactor, while the volatile fatty acids (VFAs) accumulated and extracellular polymeric substances (EPS) of the anaerobic granular sludge increased with NH4(+)-N concentration rising to 1000mg/L, without any rebounding during 30days of operation. Decreasing NH4(+)-N concentration to 500mg/L in influent, the COD removal efficiency recovered to about 85% after 26days. 1000mg/L of NH4(+)-N in leachate was suggested to be the inhibition threshold in EGSB reactor. High-throughput sequencing results showed little changes in microbial communities of the sludge for a high NH4(+)-N concentration, indicating that the survival of most microorganisms was not affected under such a condition. It inhibited the bioactivity of the microorganisms, resulting in decrease of the COD removal efficiency. Copyright © 2015 Elsevier Ltd. All rights reserved.

Maximum solid concentrations of coal water slurries predicted by neural network models

Energy Technology Data Exchange (ETDEWEB)

Cheng, Jun; Li, Yanchang; Zhou, Junhu; Liu, Jianzhong; Cen, Kefa

2010-12-15

The nonlinear back-propagation (BP) neural network models were developed to predict the maximum solid concentration of coal water slurry (CWS) which is a substitute for oil fuel, based on physicochemical properties of 37 typical Chinese coals. The Levenberg-Marquardt algorithm was used to train five BP neural network models with different input factors. The data pretreatment method, learning rate and hidden neuron number were optimized by training models. It is found that the Hardgrove grindability index (HGI), moisture and coalification degree of parent coal are 3 indispensable factors for the prediction of CWS maximum solid concentration. Each BP neural network model gives a more accurate prediction result than the traditional polynomial regression equation. The BP neural network model with 3 input factors of HGI, moisture and oxygen/carbon ratio gives the smallest mean absolute error of 0.40%, which is much lower than that of 1.15% given by the traditional polynomial regression equation. (author)

Detection and quantification of the solid component in pulmonary subsolid nodules by semiautomatic segmentation

Energy Technology Data Exchange (ETDEWEB)

Scholten, Ernst T. [University Medical Center, Department of Radiology, Utrecht (Netherlands); Kennemer Gasthuis, Department of Radiology, Haarlem (Netherlands); Jacobs, Colin; Riel, Sarah van [Radboud University Medical Center, Diagnostic Image Analysis Group, Nijmegen (Netherlands); Ginneken, Bram van [Radboud University Medical Center, Diagnostic Image Analysis Group, Nijmegen (Netherlands); Fraunhofer MEVIS, Bremen (Germany); Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen (Netherlands); University of Groningen, University Medical Centre Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Oudkerk, Matthijs [University of Groningen, University Medical Centre Groningen, Center for Medical Imaging-North East Netherlands, Groningen (Netherlands); Koning, Harry J. de [Erasmus Medical Center, Department of Public Health, Rotterdam (Netherlands); Horeweg, Nanda [Erasmus Medical Center, Department of Public Health, Rotterdam (Netherlands); Erasmus Medical Center, Department of Pulmonology, Rotterdam (Netherlands); Prokop, Mathias [Radboud University Medical Center, Department of Radiology, Nijmegen (Netherlands); Gietema, Hester A.; Mali, Willem P.T.M.; Jong, Pim A. de [University Medical Center, Department of Radiology, Utrecht (Netherlands)

2014-10-07

To determine whether semiautomatic volumetric software can differentiate part-solid from nonsolid pulmonary nodules and aid quantification of the solid component. As per reference standard, 115 nodules were differentiated into nonsolid and part-solid by two radiologists; disagreements were adjudicated by a third radiologist. The diameters of solid components were measured manually. Semiautomatic volumetric measurements were used to identify and quantify a possible solid component, using different Hounsfield unit (HU) thresholds. The measurements were compared with the reference standard and manual measurements. The reference standard detected a solid component in 86 nodules. Diagnosis of a solid component by semiautomatic software depended on the threshold chosen. A threshold of -300 HU resulted in the detection of a solid component in 75 nodules with good sensitivity (90 %) and specificity (88 %). At a threshold of -130 HU, semiautomatic measurements of the diameter of the solid component (mean 2.4 mm, SD 2.7 mm) were comparable to manual measurements at the mediastinal window setting (mean 2.3 mm, SD 2.5 mm [p = 0.63]). Semiautomatic segmentation of subsolid nodules could diagnose part-solid nodules and quantify the solid component similar to human observers. Performance depends on the attenuation segmentation thresholds. This method may prove useful in managing subsolid nodules. (orig.)

Influence of lactose hydrolysis and solids concentration on alcohol production by yeast in acid whey ultrafiltrate

Energy Technology Data Exchange (ETDEWEB)

O' leary, V S; Sutton, C; Bencivengo, M; Sullivan, B; Holsinger, V H

1977-11-01

Alcohol yields of 6.5 percent were obtained with Saccharomyces cerevisiae in lactase-hydrolyzed acid whey permeate containing 30 to 35 percent total solids. Maximum alcohol yields obtained with Kluyveromyces fragilis were 4.5 percent in lactase-hydrolyzed acid whey permeate at a solids concentration of 20 percent and 3.7 percent in normal permeate at a solids concentration of 10 percent. Saccharomyces cerevisiae efficiently converted the glucose present in lactase-hydrolyzed whey permeates containing 5 to 30 percent total solids (2 to 13 percent glucose) to alcohol. However, the galactose, which comprised about half the available carbohydrate in lactase-hydrolyzed whey, was not utilized by S. cerevisiae, so that even though alcohol yields were higher when this organism was used, the process was wasteful in that a substantial proportion of the substrate was not fermented. For the process to become commercially feasible, an efficient means of rapidly converting both the galactose and glucose to alcohol must be found.

The Emission, Lifetimes, and Formation Threshold of the Vegard-Kaplan Transition of Solid Nitrogen Exposed to Far-ultraviolet Radiation

Science.gov (United States)

Lu, Hsiao-Chi; Lo, Jen-Iu; Peng, Yu-Chain; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming

2016-11-01

Irradiation of solid nitrogen at 4 K with far-ultraviolet light from a synchrotron caused excitation to the upper state of the Vegard-Kaplan (VK) system; the emission in that system was simultaneously recorded in wavelength region 200-440 nm. The lifetimes of emission lines for VK (0, 1) to (0, 12) transitions were measured in the range of 2.12 ˜ 2.65 s. The threshold wavelength to observe the VK emission was 175.0 ± 3.5 nm, corresponding to energy 7.08 ± 0.14 eV. This investigation of the generation of icy VK nitrogen enhances our understanding of its photochemistry in space.

THE EMISSION, LIFETIMES, AND FORMATION THRESHOLD OF THE VEGARD–KAPLAN TRANSITION OF SOLID NITROGEN EXPOSED TO FAR-ULTRAVIOLET RADIATION

Energy Technology Data Exchange (ETDEWEB)

Lu, Hsiao-Chi; Lo, Jen-Iu; Peng, Yu-Chain; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming, E-mail: bmcheng@nsrrc.org.tw [National Synchrotron Radiation Research Center, No. 101, Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China)

2016-11-20

Irradiation of solid nitrogen at 4 K with far-ultraviolet light from a synchrotron caused excitation to the upper state of the Vegard–Kaplan (VK) system; the emission in that system was simultaneously recorded in wavelength region 200–440 nm. The lifetimes of emission lines for VK (0, 1) to (0, 12) transitions were measured in the range of 2.12 ∼ 2.65 s. The threshold wavelength to observe the VK emission was 175.0 ± 3.5 nm, corresponding to energy 7.08 ± 0.14 eV. This investigation of the generation of icy VK nitrogen enhances our understanding of its photochemistry in space.

THE EMISSION, LIFETIMES, AND FORMATION THRESHOLD OF THE VEGARD–KAPLAN TRANSITION OF SOLID NITROGEN EXPOSED TO FAR-ULTRAVIOLET RADIATION

International Nuclear Information System (INIS)

Lu, Hsiao-Chi; Lo, Jen-Iu; Peng, Yu-Chain; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming

2016-01-01

Irradiation of solid nitrogen at 4 K with far-ultraviolet light from a synchrotron caused excitation to the upper state of the Vegard–Kaplan (VK) system; the emission in that system was simultaneously recorded in wavelength region 200–440 nm. The lifetimes of emission lines for VK (0, 1) to (0, 12) transitions were measured in the range of 2.12 ∼ 2.65 s. The threshold wavelength to observe the VK emission was 175.0 ± 3.5 nm, corresponding to energy 7.08 ± 0.14 eV. This investigation of the generation of icy VK nitrogen enhances our understanding of its photochemistry in space.

Round Robin test for the determination of nitrogen concentration in solid Lithium

International Nuclear Information System (INIS)

Favuzza, P.; Antonelli, A.; Furukawa, T.; Groeschel, F.; Hedinger, R.; Higashi, T.; Hirakawa, Y.; Iijima, M.; Ito, Y.; Kanemura, T.; Knaster, J.; Kondo, H.; Miccichè, G.; Nitti, F.S.; Ohira, S.; Severi, M.; Sugimoto, M.; Suzuki, A.; Traversi, R.; Wakai, E.

2016-01-01

Highlights: • Nitrogen contained in solid Lithium is converted into Ammonium ion. • Ammonium ion is suitably quantified by ionic chromatograph or by Ammonia sensor. • Good agreement of the partner’s results has been achieved. • Maximum operative reproducibility and blank subtraction are necessary. - Abstract: Three different partners, ENEA, JAEA ed University of Tokyo, have been involved during 2014–2015 in the Round Robin experimentation for the assessment of the soundness of the analitycal procedure for the determination of the Nitrogen impurities contained inside a solid Lithium sample. Two different kinds of Lithium samples, differing by about an order of magnitude in Nitrogen concentration (∼230 wppm; ∼20–30 wppm), have been selected for this cross analysis. The agreement of the achieved results appears very good for what concerns the most concentrated Lithium and indicates each partner’s procedure is appropriate and intrinsecally able to lead to meaningful values, characterized by a relative uncertainty of just few %. The smaller agreement in the case of the less concentrated Lithium anyway points out that particular attention must be paid to reduce as much as possible any source of external contamination and highlights the importance of the proper blank subtraction.

Round Robin test for the determination of nitrogen concentration in solid Lithium

Energy Technology Data Exchange (ETDEWEB)

Favuzza, P., E-mail: paolo.favuzza@enea.it [ENEA Center, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Antonelli, A. [ENEA Research Center, Brasimone, 40035, Camugnano (Italy); Furukawa, T. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Groeschel, F. [KIT Research Center, Hermann-von-Helmholtz-Platz 1,76344 Eggenstein-Leopoldshafen (Germany); Hedinger, R. [F4E Research Center, Boltzmannstraße 2, 85748 Garching (Germany); Higashi, T. [University of Tokyo (Japan); Hirakawa, Y.; Iijima, M.; Ito, Y.; Kanemura, T. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Knaster, J. [IFMIF-EVEDA Project Team, Rokkasho (Japan); Kondo, H. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Miccichè, G.; Nitti, F.S. [ENEA Research Center, Brasimone, 40035, Camugnano (Italy); Ohira, S. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Severi, M. [University of Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Sugimoto, M. [JAEA Research Center, Rokkasho (Japan); Suzuki, A. [University of Tokyo (Japan); Traversi, R. [University of Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Wakai, E. [JAEA Research Center, Tokai-mura, Ibaraki (Japan)

2016-06-15

Highlights: • Nitrogen contained in solid Lithium is converted into Ammonium ion. • Ammonium ion is suitably quantified by ionic chromatograph or by Ammonia sensor. • Good agreement of the partner’s results has been achieved. • Maximum operative reproducibility and blank subtraction are necessary. - Abstract: Three different partners, ENEA, JAEA ed University of Tokyo, have been involved during 2014–2015 in the Round Robin experimentation for the assessment of the soundness of the analitycal procedure for the determination of the Nitrogen impurities contained inside a solid Lithium sample. Two different kinds of Lithium samples, differing by about an order of magnitude in Nitrogen concentration (∼230 wppm; ∼20–30 wppm), have been selected for this cross analysis. The agreement of the achieved results appears very good for what concerns the most concentrated Lithium and indicates each partner’s procedure is appropriate and intrinsecally able to lead to meaningful values, characterized by a relative uncertainty of just few %. The smaller agreement in the case of the less concentrated Lithium anyway points out that particular attention must be paid to reduce as much as possible any source of external contamination and highlights the importance of the proper blank subtraction.

DOE approach to threshold quantities

International Nuclear Information System (INIS)

Wickham, L.E.; Kluk, A.F.; Department of Energy, Washington, DC)

1985-01-01

The Department of Energy (DOE) is developing the concept of threshold quantities for use in determining which waste materials must be handled as radioactive waste and which may be disposed of as nonradioactive waste at its sites. Waste above this concentration level would be managed as radioactive or mixed waste (if hazardous chemicals are present); waste below this level would be handled as sanitary waste. Ideally, the threshold must be set high enough to significantly reduce the amount of waste requiring special handling. It must also be low enough so that waste at the threshold quantity poses a very small health risk and multiple exposures to such waste would still constitute a small health risk. It should also be practical to segregate waste above or below the threshold quantity using available instrumentation. Guidance is being prepared to aid DOE sites in establishing threshold quantity values based on pathways analysis using site-specific parameters (waste stream characteristics, maximum exposed individual, population considerations, and site specific parameters such as rainfall, etc.). A guidance dose of between 0.001 to 1.0 mSv/y (0.1 to 100 mrem/y) was recommended with 0.3 mSv/y (30 mrem/y) selected as the guidance dose upon which to base calculations. Several tasks were identified, beginning with the selection of a suitable pathway model for relating dose to the concentration of radioactivity in the waste. Threshold concentrations corresponding to the guidance dose were determined for waste disposal sites at a selected humid and arid site. Finally, cost-benefit considerations at the example sites were addressed. The results of the various tasks are summarized and the relationship of this effort with related developments at other agencies discussed

THE STRUCTURE AND CONCENTRATION OF SOLIDS IN PHOTORECEPTOR CELLS STUDIED BY REFRACTOMETRY AND INTERFERENCE MICROSCOPY

Science.gov (United States)

Sidman, Richard L.

1957-01-01

Fragments of freshly obtained retinas of several vertebrate species were studied by refractometry, with reference to the structure of the rods and cones. The findings allowed a reassessment of previous descriptions based mainly on fixed material. The refractometric method was used also to measure the refractice indices and to calculate the concentrations of solids and water in the various cell segments. The main quantitative data were confirmed by interference microscopy. When examined by the method of refractometry the outer segments of freshly prepared retinal rods appear homogeneous. Within a few minutes a single eccentric longitudinal fiber appears, and transverse striations may develop. These changes are attributed to imbibition of water and swelling in structures normally too small for detection by light microscopy. The central "core" of outer segments and the chromophobic disc between outer and inner segments appear to be artifacts resulting from shrinkage during dehydration. The fresh outer segments of cones, and the inner segments of rods and cones also are described and illustrated. The volumes, refractive indices, concentrations of solids, and wet and dry weights of various segments of the photoreceptor cells were tabulated. Rod outer segments of the different species vary more than 100-fold in volume and mass but all have concentrations of solids of 40 to 43 per cent. Cone outer segments contain only about 30 per cent solids. The myoids, paraboloids, and ellipsoids of the inner segments likewise have characteristic refractive indices and concentrations of solids. Some of the limitations and particular virtues of refractometry as a method for quantitative analysis of living cells are discussed in comparison with more conventional biochemical techniques. Also the shapes and refractive indices of the various segments of photoreceptor cells are considered in relation to the absorption and transmission of light. The Stiles-Crawford effect can be accounted

Music effect on pain threshold evaluated with current perception threshold

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

AIM: Music relieves anxiety and psychotic tension. This effect of music is applied to surgical operation in the hospital and dental office. It is still unclear whether this music effect is only limited to the psychological aspect but not to the physical aspect or whether its music effect is influenced by the mood or emotion of audience. To elucidate these issues, we evaluated the music effect on pain threshold by current perception threshold (CPT) and profile of mood states (POMC) test. METHODS: Healthy 30 subjects (12 men, 18 women, 25-49 years old, mean age 34.9) were tested. (1)After POMC test, all subjects were evaluated pain threshold with CPT by Neurometer (Radionics, USA) under 6 conditions, silence, listening to the slow tempo classic music, nursery music, hard rock music, classic paino music and relaxation music with 30 seconds interval. (2)After Stroop color word test as the stresser, pain threshold was evaluated with CPT under 2 conditions, silence and listening to the slow tempo classic music. RESULTS: Under litening to the music, CPT sores increased, especially 2 000 Hz level related with compression, warm and pain sensation. Type of music, preference of music and stress also affected CPT score. CONCLUSION: The present study demonstrated that the concentration on the music raise the pain threshold and that stress and mood influence the music effect on pain threshold.

Critical micelle concentration values for different surfactants measured with solid-phase microextraction fibers

NARCIS (Netherlands)

Haftka, Joris J H; Scherpenisse, Peter; Oetter, G??nter; Hodges, Geoff; Eadsforth, Charles V.; Kotthoff, Matthias; Hermens, Joop L M

The amphiphilic nature of surfactants drives the formation of micelles at the critical micelle concentration (CMC). Solid-phase microextraction (SPME) fibres were used in the present study to measure CMC values of twelve nonionic, anionic, cationic and zwitterionic surfactants. The SPME derived CMC

Decadal-scale changes in dissolved-solids concentrations in groundwater used for public supply, Salt Lake Valley, Utah

Science.gov (United States)

Thiros, Susan A.; Spangler, Larry

2010-01-01

Basin-fill aquifers are a major source of good-quality water for public supply in many areas of the southwestern United States and have undergone increasing development as populations have grown over time. During 2005, the basin-fill aquifer in Salt Lake Valley, Utah, provided approximately 75,000 acre-feet, or about 29 percent of the total amount of water used by a population of 967,000. Groundwater in the unconsolidated basin-fill deposits that make up the aquifer occurs under unconfined and confined conditions. Water in the shallow unconfined part of the groundwater system is susceptible to near-surface contamination and generally is not used as a source of drinking water. Groundwater for public supply is withdrawn from the deeper unconfined and confined parts of the system, termed the principal aquifer, because yields generally are greater and water quality is better (including lower dissolved-solids concentrations) than in the shallower parts of the system. Much of the water in the principal aquifer is derived from recharge in the adjacent Wasatch Range (mountain-block recharge). In many areas, the principal aquifer is separated from the overlying shallow aquifer by confining layers of less permeable, fine-grained sediment that inhibit the downward movement of water and any potential contaminants from the surface. Nonetheless, under certain hydrologic conditions, human-related activities can increase dissolved-solids concentrations in the principal aquifer and result in groundwater becoming unsuitable for consumption without treatment or mixing with water having lower dissolved-solids concentrations. Dissolved-solids concentrations in areas of the principal aquifer used for public supply typically are less than 500 milligrams per liter (mg/L), the U.S. Environmental Protection Agency (EPA) secondary (nonenforceable) drinking-water standard. However, substantial increases in dissolved-solids concentrations in the principal aquifer have been documented in some

Short communication: The influence of solids concentration and bleaching agent on bleaching efficacy and flavor of sweet whey powder.

Science.gov (United States)

Jervis, M G; Smith, T J; Drake, M A

2015-04-01

Recent studies have demonstrated the effect of bleaching conditions and bleaching agent on flavor and functional properties of whey protein ingredients. Solids concentration at bleaching significantly affected bleaching efficacy and flavor effects of different bleaching agents. It is not known if these parameters influence quality of sweet whey powder (SWP). The purpose of this study was to determine the effects of solids concentration and bleaching agent on the flavor and bleaching efficacy of SWP. Colored cheddar whey was manufactured, fat separated, and pasteurized. Subsequently, the whey (6.7% solids) was bleached, concentrated using reverse osmosis (RO) to 14% solids, and then spray dried, or whey was concentrated before bleaching and then spray dried. Bleaching treatments included a control (no bleaching, 50 °C, 60 min), hydrogen peroxide (HP; 250 mg/kg, 50 °C, 60 min), benzoyl peroxide (50 mg/kg, 50 °C, 60 min), lactoperoxidase (20 mg/kg of HP, 50 °C, 30 min), and external peroxidase (MaxiBright, DSM Food Specialties, Delft, the Netherlands; 2 dairy bleaching units/mL, 50 °C, 30 min). The experiment was repeated in triplicate. Sensory properties and volatile compounds of SWP were evaluated by a trained panel and gas chromatography-mass spectrometry, respectively. Bleaching efficacy (norbixin destruction) and benzoic acid were measured by HPLC. Differences in bleaching efficacy, sensory and volatile compound profiles, and benzoic acid were observed with different bleaching agents, consistent with previous studies. Solids concentration affected bleaching efficacy of HP, but not other bleaching agents. The SWP from whey bleached with HP or lactoperoxidase following RO had increased cardboard and fatty flavors and higher concentrations of lipid oxidation compounds compared with SWP from whey bleached before RO. The SWP bleached with benzoyl peroxide after RO contained less benzoic acid than SWP from whey bleached before RO. These results indicate that

A data reconnaissance on the effect of suspended-sediment concentrations on dissolved-solids concentrations in rivers and tributaries in the Upper Colorado River Basin

Science.gov (United States)

Tillman, Fred D.; Anning, David W.

2014-01-01

The Colorado River is one of the most important sources of water in the western United States, supplying water to over 35 million people in the U.S. and 3 million people in Mexico. High dissolved-solids loading to the River and tributaries are derived primarily from geologic material deposited in inland seas in the mid-to-late Cretaceous Period, but this loading may be increased by human activities. High dissolved solids in the River causes substantial damages to users, primarily in reduced agricultural crop yields and corrosion. The Colorado River Basin Salinity Control Program was created to manage dissolved-solids loading to the River and has focused primarily on reducing irrigation-related loading from agricultural areas. This work presents a reconnaissance of existing data from sites in the Upper Colorado River Basin (UCRB) in order to highlight areas where suspended-sediment control measures may be useful in reducing dissolved-solids concentrations. Multiple linear regression was used on data from 164 sites in the UCRB to develop dissolved-solids models that include combinations of explanatory variables of suspended sediment, flow, and time. Results from the partial t-test, overall likelihood ratio, and partial likelihood ratio on the models were used to group the sites into categories of strong, moderate, weak, and no-evidence of a relation between suspended-sediment and dissolved-solids concentrations. Results show 68 sites have strong or moderate evidence of a relation, with drainage areas for many of these sites composed of a large percentage of clastic sedimentary rocks. These results could assist water managers in the region in directing field-scale evaluation of suspended-sediment control measures to reduce UCRB dissolved-solids loading.

Successive membrane separation processes simplify concentration of lipases produced by Aspergillus niger by solid-state fermentation.

Science.gov (United States)

Reinehr, Christian Oliveira; Treichel, Helen; Tres, Marcus Vinicius; Steffens, Juliana; Brião, Vandré Barbosa; Colla, Luciane Maria

2017-06-01

In this study, we developed a simplified method for producing, separating, and concentrating lipases derived from solid-state fermentation of agro-industrial residues by filamentous fungi. First, we used Aspergillus niger to produce lipases with hydrolytic activity. We analyzed the separation and concentration of enzymes using membrane separation processes. The sequential use of microfiltration and ultrafiltration processes made it possible to obtain concentrates with enzymatic activities much higher than those in the initial extract. The permeate flux was higher than 60 L/m 2 h during microfiltration using 20- and 0.45-µm membranes and during ultrafiltration using 100- and 50-kDa membranes, where fouling was reversible during the filtration steps, thereby indicating that the fouling may be removed by cleaning processes. These results demonstrate the feasibility of lipase production using A. niger by solid-state fermentation of agro-industrial residues, followed by successive tangential filtration with membranes, which simplify the separation and concentration steps that are typically required in downstream processes.

Threshold pump power of a solar-pumped dye laser

Science.gov (United States)

Lee, Ja H.; Kim, Kyung C.; Kim, Kyong H.

1988-01-01

Threshold solar power for dye laser pumping has been determined by measuring the gain of a rhodamine 6G dye laser amplifier at various solar-simulated irradiances on an amplifier cell. The measured threshold was 20,000 solar constants (2.7 kW/sq cm) for the dye volume of 2 x 5 x 40 cu mm and the optimum dye concentration of 0.001 M. The threshold is about one-third of that achievable with a high-intensity solar concentrator.

Generalization of the Nernst-Einstein equation for self-diffusion in high-defect-concentration solids

International Nuclear Information System (INIS)

McKee, R.A.

1981-01-01

It is shown that the Nernst-Einstein equation can be generalized for a high defect concentration solid to relate the mobility or conductivity to the self-diffusion coefficient. This relationship is derived assuming that the diffusing particles interact strongly and that the mobility is concentration-dependent. It is derived for interstitial disordered structures, but it is perfectly general to any mechanism of self diffusion as long as diffusion in a pure system is considered

Thresholds of whole-blood β-hydroxybutyrate and glucose concentrations measured with an electronic hand-held device to identify ovine hyperketonemia.

Science.gov (United States)

Pichler, M; Damberger, A; Schwendenwein, I; Gasteiner, J; Drillich, M; Iwersen, M

2014-03-01

Metabolic disorders, especially hyperketonemia, are very common in dairy sheep. The whole-blood concentrations of β-hydroxybutyrate (BHBA) and glucose can be determined by commercially available electronic hand-held devices, which are used in human medicine and for the detection of ketosis in dairy cows. The aim of this study was to evaluate the suitability of the hand-held device Precision Xceed (PX; Abbott Diabetes Care Inc., Abbott Park, IL) to detect hyperketonemia in ewes. An additional objective of this study was to evaluate the agreement between samples obtained by minimal invasive venipuncture of an ear vein and measurements of whole-blood samples from the jugular vein (vena jugularis, v. jug.). Blood samples taken from the v. jug. were collected from 358 ewes on 4 different farms. These samples and a blood drop obtained from an ear vein were analyzed simultaneously on farm with the PX. For method comparison, the samples obtained from the v. jug. were also analyzed by standard methods, which served as the gold standard at the Central Laboratory of the University of Veterinary Medicine Vienna, Austria. The correlation coefficients between the serum BHBA concentration and the concentrations measured with the hand-held meter in the whole blood from an ear vein and the v. jug. were 0.94 and 0.96, respectively. The correlation coefficients of plasma and whole-blood glucose concentration were 0.68 for the v. jug. and 0.47 for the ear vein. The mean glucose concentration was significantly lower in animals classified as hyperketonemic (BHBA ≥ 1.6 mmol/L) compared with healthy ewes. Whole-blood concentrations of BHBA and glucose measured with the PX from v. jug. showed a constant negative bias of 0.15 mmol/L and 8.4 mg/dL, respectively. Hence, a receiver operating characteristic analysis was performed to determine thresholds for the PX to detect hyperketonemia in ewes. This resulted in thresholds for moderate ketosis of BHBA concentrations of 0.7 mmol/L in blood

FACT light collection - solid light concentrators in Cherenkov Astronomy

Energy Technology Data Exchange (ETDEWEB)

Braun, Isabel [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Collaboration: FACT-Collaboration

2011-07-01

Pixelized cameras of Imaging Atmospheric Cherenkov Telescopes use hollow light guides with reflective surfaces based on the Winston cone design. These cones minimize insensitive spaces between the photo sensors and shield the camera from stray background light by limiting the angular acceptance to the primary reflector area. FACT (First G-APD Cherenkov Telescope) will be the first IACT with Geiger-mode avalanche photodiodes as light sensors. Solid light concentrators complementing these sensors will be used instead of hollow Winston cones. We will present simulations and measurements of our light collector design, which was optimized for the requirements of the FACT telescope and detector, and discuss the specific differences to more traditional solutions.

Distribution of Total Suspended Solids Concentration in a River

Directory of Open Access Journals (Sweden)

Ahmad Hanif Asyhar

2012-08-01

Full Text Available Disposal of either industrial or nonindustrial wastewater into a river has a potential to cause riverpollution. Because each load of wastewater discharged into a river contains physical, chemical, and biological parametersthat determine water quality, so that it can affect the dissolved oxygen concentration in a river. Therefore the conductedresearch was aimed to determine the pattern of pollutant dispersion in Surabaya River within the section that is closed tothe Karang Pilang Monitoring Station - Surabaya. Parameter used in this research was Total Suspended Solids (TSS. Themethod used was the finite volume method with Quadratic Upwind Interpolation Convective Kinematics (QUICK schemeby means of developing models of dispersion water pollutants in a river. The governing equation was controlled by the lawsof mass conservation, momentum conservation, and pollution transport equation. Further, these equations were solvedusing numerical calculation and followed by numerical simulation. From the numerical simulation results, it can beconcluded that the magnitude of pollutant dispersion is determined by the initial discharged TSS concentrations into theriver, however the longitudinal direction is more dominantly influenced than in lateral directions.

Resolution of the threshold fracture energy paradox for solid particle erosion

Science.gov (United States)

Peck, Daniel; Volkov, Grigory; Mishuris, Gennady; Petrov, Yuri

2016-12-01

Previous models of a single erosion impact, for a rigid axisymmetric indenter defined by the shape function ?, have shown that a critical shape parameter ? exists which determines the behaviour of the threshold fracture energy. However, repeated investigations into this parameter have found no physical explanation for its value. Again utilising the notion of incubation time prior to fracture, this paper attempts to provide a physical explanation of this phenomena by introducing a supersonic stage into the model. The final scheme allows for the effect of waves along the indenters contact area to be taken into account. The effect of this physical characteristic of the impact on the threshold fracture energy and critical shape parameter ? are investigated and discussed.

Bulk metal concentrations versus total suspended solids in rivers: Time-invariant & catchment-specific relationships.

Science.gov (United States)

Nasrabadi, Touraj; Ruegner, Hermann; Schwientek, Marc; Bennett, Jeremy; Fazel Valipour, Shahin; Grathwohl, Peter

2018-01-01

Suspended particles in rivers can act as carriers of potentially bioavailable metal species and are thus an emerging area of interest in river system monitoring. The delineation of bulk metals concentrations in river water into dissolved and particulate components is also important for risk assessment. Linear relationships between bulk metal concentrations in water (CW,tot) and total suspended solids (TSS) in water can be used to easily evaluate dissolved (CW, intercept) and particle-bound metal fluxes (CSUS, slope) in streams (CW,tot = CW + CSUS TSS). In this study, we apply this principle to catchments in Iran (Haraz) and Germany (Ammer, Goldersbach, and Steinlach) that show differences in geology, geochemistry, land use and hydrological characteristics. For each catchment, particle-bound and dissolved concentrations for a suite of metals in water were calculated based on linear regressions of total suspended solids and total metal concentrations. Results were replicable across sampling campaigns in different years and seasons (between 2013 and 2016) and could be reproduced in a laboratory sedimentation experiment. CSUS values generally showed little variability in different catchments and agree well with soil background values for some metals (e.g. lead and nickel) while other metals (e.g. copper) indicate anthropogenic influences. CW was elevated in the Haraz (Iran) catchment, indicating higher bioavailability and potential human and ecological health concerns (where higher values of CSUS/CW are considered as a risk indicator).

Calibration of a turbidity meter for making estimates of total suspended solids concentrations and beam attenuation coefficients in field experiments

Science.gov (United States)

Usry, J. W.; Whitlock, C. H.

1981-01-01

Management of water resources such as a reservoir requires using analytical models which describe such parameters as the suspended sediment field. To select or develop an appropriate model requires making many measurements to describe the distribution of this parameter in the water column. One potential method for making those measurements expeditiously is to measure light transmission or turbidity and relate that parameter to total suspended solids concentrations. An instrument which may be used for this purpose was calibrated by generating curves of transmission measurements plotted against measured values of total suspended solids concentrations and beam attenuation coefficients. Results of these experiments indicate that field measurements made with this instrument using curves generated in this study should correlate with total suspended solids concentrations and beam attenuation coefficients in the water column within 20 percent.

The PM2.5 threshold for aerosol extinction in the Beijing megacity

Science.gov (United States)

Kong, Lingbin; Xin, Jinyuan; Liu, Zirui; Zhang, Kequan; Tang, Guiqian; Zhang, Wenyu; Wang, Yuesi

2017-10-01

Particulate pollution has remained at a high level in the megacity of Beijing in the past decade. The PM2.5, PM10, aerosol optical depth (AOD), Angstrom exponent(α), and PM2.5/PM10 ratio (the proportion of PM2.5 in PM10) in Beijing were 70±6 μg m-3, 128±6 μg m-3, 0.57 ± 0.05, 1.10 ± 0.08, 45 ± 4%, respectively, from 2005 to 2014. The annual means of PM concentration, AOD, α, and PM2.5/PM10 ratio decreased slightly during this decade, meanwhile PM concentration increased in the winter. Furthermore, we found there were thresholds of PM2.5 concentration for aerosol extinction. When the PM concentration was lower than a certain threshold, AOD decreased quickly with the decline of PM concentration. To make the improvement of the particle pollution more noticeable, the PM concentration should be controlled under the threshold. The annual averaged threshold is 63 μg m-3, and the threshold values reached the maximum of 74 μg m-3 in spring, ranged from 54 to 56 μg m-3 in the three other seasons. The threshold values ranged from 55 to 77 μg m-3 under other relevant factors, including air masses directions and relative humidity.

Improved estimates of filtered total mercury loadings and total mercury concentrations of solids from potential sources to Sinclair Inlet, Kitsap County, Washington

Science.gov (United States)

Paulson, Anthony J.; Conn, Kathleen E.; DeWild, John F.

2013-01-01

Previous investigations examined sources and sinks of mercury to Sinclair Inlet based on historic and new data. This included an evaluation of mercury concentrations from various sources and mercury loadings from industrial discharges and groundwater flowing from the Bremerton naval complex to Sinclair Inlet. This report provides new data from four potential sources of mercury to Sinclair Inlet: (1) filtered and particulate total mercury concentrations of creek water during the wet season, (2) filtered and particulate total mercury releases from the Navy steam plant following changes in the water softening process and discharge operations, (3) release of mercury from soils to groundwater in two landfill areas at the Bremerton naval complex, and (4) total mercury concentrations of solids in dry dock sumps that were not affected by bias from sequential sampling. The previous estimate of the loading of filtered total mercury from Sinclair Inlet creeks was based solely on dry season samples. Concentrations of filtered total mercury in creek samples collected during wet weather were significantly higher than dry weather concentrations, which increased the estimated loading of filtered total mercury from creek basins from 27.1 to 78.1 grams per year. Changes in the concentrations and loading of filtered and particulate total mercury in the effluent of the steam plant were investigated after the water softening process was changed from ion-exchange to reverse osmosis and the discharge of stack blow-down wash began to be diverted to the municipal water-treatment plant. These changes reduced the concentrations of filtered and particulate total mercury from the steam plant of the Bremerton naval complex, which resulted in reduced loadings of filtered total mercury from 5.9 to 0.15 grams per year. Previous investigations identified three fill areas on the Bremerton naval complex, of which the western fill area is thought to be the largest source of mercury on the base

Determination of the concentration of total suspends solids (TSS) and heavy metals in basin rio Morote, Nicoya, Guanacaste

International Nuclear Information System (INIS)

Sanchez Murillo, Ricardo; Leon, Sandra; Saravia, Ana Yuri; Mena Sanchez, Carlos de

2009-01-01

The total concentration of suspends solids and heavy metals were determined of the Basin of rio Morote. The study spanned six sampling campaigns between April 2003 and May 2005. Sampling points were selected to correspond to places from the high basin to the mouth of the rio Morote in the Golfo de Nicoya. Suspends total solids concentration (TSS) on average exceeds 200 mg/L during the rainy season at the mouth. Enrichment of metals as: Cu, Ni, Cd and Fe was found in riverbed sediments; but not in Pb. The concentration of Zn has been near the limit value (200 mg/kg) in the dry season, value which has been established for the Environmental Protection Agency of United States (EPA). (author) [es

An Integrated Instrumentation System for Velocity, Concentration and Mass Flow Rate Measurement of Solid Particles Based on Electrostatic and Capacitance Sensors

Directory of Open Access Journals (Sweden)

Jian Li

2015-12-01

Full Text Available The online and continuous measurement of velocity, concentration and mass flow rate of pneumatically conveyed solid particles for the high-efficiency utilization of energy and raw materials has become increasingly significant. In this paper, an integrated instrumentation system for the velocity, concentration and mass flow rate measurement of dense phase pneumatically conveyed solid particles based on electrostatic and capacitance sensorsis developed. The electrostatic sensors are used for particle mean velocity measurement in combination with the cross-correlation technique, while the capacitance sensor with helical surface-plate electrodes, which has relatively homogeneous sensitivity distribution, is employed for the measurement of particle concentration and its capacitance is measured by an electrostatic-immune AC-based circuit. The solid mass flow rate can be further calculated from the measured velocity and concentration. The developed instrumentation system for velocity and concentration measurement is verified and calibrated on a pulley rig and through static experiments, respectively. Finally the system is evaluated with glass beads on a gravity-fed rig. The experimental results demonstrate that the system is capable of the accurate solid mass flow rate measurement, and the relative error is within −3%–8% for glass bead mass flow rates ranging from 0.13 kg/s to 0.9 kg/s.

Effect of initial total solids concentration on volatile fatty acid production from food waste during anaerobic acidification.

Science.gov (United States)

Wang, Quan; Jiang, Jianguo; Zhang, Yujing; Li, Kaimin

2015-01-01

The effect of initial total solids (TS) concentration on volatile fatty acid (VFAs) production from food waste under mesophilic conditions (35 °C) was determined. VFAs concentration and composition, biogas production, soluble chemical oxygen demand concentration, TS and volatile solids (VS) reduction, and ammonia nitrogen [Formula: see text] release were investigated. The VFAs concentrations were 26.10, 39.68, 59.58, and 62.64 g COD/L at TS contents of 40, 70, 100, and 130 g/L, respectively. While the VFAs' yields ranged from 0.467 to 0.799 g COD/g VSfed, decreased as initial TS increased. The percentage of propionate was not affected by TS concentration, accounting for 30.19-34.86% of the total VFAs, while a higher percentage of butyrate and lower percentage of acetate was achieved at a higher TS concentration. Biogas included mainly hydrogen and carbon dioxide and the maximum hydrogen yield of 148.9 ml/g VSfed was obtained at 130 g TS/L. [Formula: see text] concentration, TS and VS reductions increased as initial TS increased. Considering the above variables, we conclude that initial TS of 100 g/L shall be the most appropriate to VFAs production.

Acute phytotoxicity of seven metals alone and in mixture: Are Italian soil threshold concentrations suitable for plant protection?

International Nuclear Information System (INIS)

Baderna, Diego; Lomazzi, Eleonora; Pogliaghi, Alberto; Ciaccia, Gianluca; Lodi, Marco; Benfenati, Emilio

2015-01-01

Metals can pollute soils in both urban and rural areas with severe impacts on the health of humans, plants and animals living there. Information on metal toxicity is therefore important for ecotoxicology. This study investigated the phytotoxicity of different metals frequently found as pollutants in soils: arsenic, cadmium, chromium, lead, mercury, nickel and zinc. Cucumber (Cucumis sativus), sorghum (Sorghum saccharatum) and cress (Lepidium sativum) seeds were used as models for other plants used in human nutrition such as cereals, rice, fruits and vegetables. The 72-h germination rate and root elongations were selected as short-term ecotoxicological endpoints in seeds exposed to single metals and mixtures. Metals were spiked onto OECD standard soils in concentrations comparable to current Italian contamination threshold concentrations for residential and commercial soils. Arsenic, chromium, mercury and nickel were the most toxic metals in our experimental conditions, particularly to cress seeds (5.172, 152 and 255.4 mg/kg as 72 h IC50 for arsenic, mercury and nickel respectively). Italian limits were acceptable for plant protection only for exposure to each metal alone but not for the mixtures containing all the metals concentrations expected by their respective legislative threshold. The effects of the mixture were class-specific: trends were comparable in dicots but different in monocots. The response induced by the mixture at high concentrations differed from that theoretically obtainable by summing the effects of the individual metals. This might be due to partial antagonism of the metals in soil or to the formation of complexes between the metals, which reduce the bioavailability of the pollutants for plants. - Graphical abstract: Metals investigated: Arsenic, Cadmium, Chromium, Lead, Mercury, Nickel and Zinc. - Highlights: • The short-term phytotoxicity of seven metals was investigated with 3 higher plants. • Italian limits for arsenic and nickel in

Acute phytotoxicity of seven metals alone and in mixture: Are Italian soil threshold concentrations suitable for plant protection?

Energy Technology Data Exchange (ETDEWEB)

Baderna, Diego, E-mail: diego.baderna@marionegri.it; Lomazzi, Eleonora; Pogliaghi, Alberto; Ciaccia, Gianluca; Lodi, Marco; Benfenati, Emilio

2015-07-15

Metals can pollute soils in both urban and rural areas with severe impacts on the health of humans, plants and animals living there. Information on metal toxicity is therefore important for ecotoxicology. This study investigated the phytotoxicity of different metals frequently found as pollutants in soils: arsenic, cadmium, chromium, lead, mercury, nickel and zinc. Cucumber (Cucumis sativus), sorghum (Sorghum saccharatum) and cress (Lepidium sativum) seeds were used as models for other plants used in human nutrition such as cereals, rice, fruits and vegetables. The 72-h germination rate and root elongations were selected as short-term ecotoxicological endpoints in seeds exposed to single metals and mixtures. Metals were spiked onto OECD standard soils in concentrations comparable to current Italian contamination threshold concentrations for residential and commercial soils. Arsenic, chromium, mercury and nickel were the most toxic metals in our experimental conditions, particularly to cress seeds (5.172, 152 and 255.4 mg/kg as 72 h IC50 for arsenic, mercury and nickel respectively). Italian limits were acceptable for plant protection only for exposure to each metal alone but not for the mixtures containing all the metals concentrations expected by their respective legislative threshold. The effects of the mixture were class-specific: trends were comparable in dicots but different in monocots. The response induced by the mixture at high concentrations differed from that theoretically obtainable by summing the effects of the individual metals. This might be due to partial antagonism of the metals in soil or to the formation of complexes between the metals, which reduce the bioavailability of the pollutants for plants. - Graphical abstract: Metals investigated: Arsenic, Cadmium, Chromium, Lead, Mercury, Nickel and Zinc. - Highlights: • The short-term phytotoxicity of seven metals was investigated with 3 higher plants. • Italian limits for arsenic and nickel in

Optoelectronic system to measure the concentration and turbidity of suspended solids in the water

International Nuclear Information System (INIS)

Valente, E.S.

1984-01-01

The selection of the site where a nuclear power plant is to be built requires intensive study of the environmental conditions. This work presents the results reached on the development of a measurement system of suspended solids based on turbidity characteristics of the water. The system consists of an optical transducer composed of an emitter and a detector of infrared light, both solid state type, whose electrical signal is electronically treated. The equipment was calibrated and certified against turbidity and concentration standards in laboratory use. The obtained results indicate the reliability of the experimental method. The utilization of the equipment at the shore reinforces its flexibility and commodity of use. (author)

Effect of strong fragrance on olfactory detection threshold.

Science.gov (United States)

Fasunla, Ayotunde James; Douglas, David Dayo; Adeosun, Aderemi Adeleke; Steinbach, Silke; Nwaorgu, Onyekwere George Benjamin

2014-09-01

To assess the olfactory threshold of healthy volunteers at the University College Hospital, Ibadan and to investigate the effect of perfume on their olfactory detection thresholds. A quasi-experimental study on olfactory detection thresholds of healthy volunteers from September 2013 to November 2013. Tertiary health institution. A structured questionniare was administered to the participants in order to obtain information on sociodemographics, occupation, ability to perceive smell, use of perfume, effects of perfume on appetite and self-confidence, history of allergy, and previous nasal surgery. Participants subjectively rated their olfactory performance. Subsequently, they had olfactory detection threshold testing done at baseline and after exposure to perfume with varied concentrations of n-butanol in a forced triple response and staircase fashion. Healthy volunteers, 37 males and 63 females, were evaluated. Their ages ranged from 19 to 59 years with a mean of 31 years ± 8. Subjectively, 94% of the participants had excellent olfactory function. In the pre-exposure forced triple response, 88% were able to detect the odor at ≤.25 mmol/l concentration while in the post-exposure forced triple response, only 66% were able to detect the odor at ≤.25 mmol/l concentration. There is also a statistical significant difference in the olfactory detection threshold score between the pre-exposure and post-exposure period in the participants (P fragrances affects the olfactory detection threshold. Therefore patients and clinicians should be aware of this and its effects on the outcome of test of olfaction. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

Challenge for lowering concentration polarization in solid oxide fuel cells

Science.gov (United States)

Shimada, Hiroyuki; Suzuki, Toshio; Yamaguchi, Toshiaki; Sumi, Hirofumi; Hamamoto, Koichi; Fujishiro, Yoshinobu

2016-01-01

In the scope of electrochemical phenomena, concentration polarization at electrodes is theoretically inevitable, and lowering the concentration overpotential to improve the performance of electrochemical cells has been a continuing challenge. Electrodes with highly controlled microstructure, i.e., high porosity and uniform large pores are therefore essential to achieve high performance electrochemical cells. In this study, state-of-the-art technology for controlling the microstructure of electrodes has been developed for realizing high performance support electrodes of solid oxide fuel cells (SOFCs). The key is controlling the porosity and pore size distribution to improve gas diffusion, while maintaining the integrity of the electrolyte and the structural strength of actual sized electrode supports needed for the target application. Planar anode-supported SOFCs developed in this study realize 5 μm thick dense electrolyte (yttria-stabilized zirconia: YSZ) and the anode substrate (Ni-YSZ) of 53.6 vol.% porosity with a large median pore diameter of 0.911 μm. Electrochemical measurements reveal that the performance of the anode-supported SOFCs improves with increasing anode porosity. This Ni-YSZ anode minimizes the concentration polarization, resulting in a maximum power density of 3.09 W cm-2 at 800 °C using humidified hydrogen fuel without any electrode functional layers.

Comparison of the intradermal irritant threshold concentrations of nine allergens from two different manufacturers in clinically nonallergic dogs in the USA.

Science.gov (United States)

Foust-Wheatcraft, Desirae A; Dell, Darin L; Rosenkrantz, Wayne S; Griffin, Craig E

2017-12-01

The intradermal irritant threshold concentration for many allergens is unknown. To determine the intradermal irritant threshold concentration (ITC) of nine allergens from two different manufacturers. Twenty privately owned clinically nonallergic dogs. Alternaria, cat dander, Dermatophagoides farinae, Chenopodium album (lamb's quarter), Xanthium strumarium (cocklebur), Prosopis glandulosa (mesquite), Morus alba (white mulberry), Cynodon dactylon (Bermuda grass) and Phleum pretense (Timothy grass) from two manufacturers (ALK; Round Rock, TX, USA and Greer ® Laboratories; Lenoir, NC, USA) were injected intradermally at two dilutions and at 15 and 30 min evaluated subjectively (1-4) and objectively (horizontal wheal diameter) by two blinded investigators. A subjective score of 3 or 4 by either investigator at either timed reading was considered positive. If both concentrations resulted in positive reactions, two additional dilutions were performed. The ITC was defined as the lowest tested concentration that elicited a positive reaction in ≥10% of animals. The ITCs were Alternaria >2,000 PNU/mL; cat dander 750 PNU/mL (ALK) and 2,000 PNU/mL (Greer ® ); D. farinae strumarium <6,000 PNU/mL; P. glandulosa <500 PNU/mL; M. alba <6,000 PNU/mL; C. dactylon <10,000 PNU/mL (ALK) and <6,000 PNU/mL (Greer ® ); and P. pretense <6,000 PNU/mL. There were significant differences in subjective scoring and objective measurement between manufacturers for Alternaria, cat dander and P. pretense. Results revealed significant positive correlation between subjective scoring and objective measurement for each time, investigator and manufacturer separately. © 2017 ESVD and ACVD.

Variation of Soluble Solids Concentration During the Day in Three Pastures During the Dry Season in the Middle River Sinú Valley

Directory of Open Access Journals (Sweden)

Emiro Suárez Paternina

2015-07-01

Full Text Available The aim of this study was to determine the concentration of soluble solids at different times of the day in three tropical pastures. The experiment was conducted at the Research Center Turipaná of Colombian Agricultural Research Corporation, located in Cereté, Colombia. During January and February of 2011, we assessed the concentration of soluble solids in three fertirrigated pastures: Panicum maximum, Cynodon nlemfuensis and Brachiaria hybrid cv. Mulato II, in an intensive model of meat production at different sampling times 7:00 and 10:00 a. m., 1:00 and 4:00 p.m. The statistical design of the experiment consisted of a block design completely randomized three-factor under 3*3*4 (pasture*stocking*time and three replicates for each evaluation day. An analysis of variance and differences were statistically significant when the means were separated by Tukey test (p<0.05. The analysis found highly significant differences (p<0.01 in the concentration of soluble solids in different pastures, in all periods of the day evaluated, with the cultivar Mulato II that presented the highest values with 9.19 %, followed by Cynodon nlemfuensis and Panicum maximum with 8.27 % and 7.07 %, respectively. The soluble solids concentration varied during the day and between pastures. The time periods close to noon —10:00 a. m. and 1:00 p. m.— presented the highest concentrations of soluble solids in all pastures; this can be used as a tool for paddock rotation.

Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery.

Science.gov (United States)

Lewis, Ryan C; Gaffney, Shannon H; Le, Matthew H; Unice, Ken M; Paustenbach, Dennis J

2012-09-01

Workers handle catalysts extensively at petroleum refineries throughout the world each year; however, little information is available regarding the airborne concentrations and plausible exposures during this type of work. In this paper, we evaluated the airborne concentrations of 15 metals and total dust generated during solid catalyst loading and unloading operations at one of the largest petroleum refineries in the world using historical industrial hygiene samples collected between 1989 and 2006. The total dust and metals, which included aluminum, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, platinum, silicon, silver, vanadium, and zinc, were evaluated in relation to the handling of four different types of solid catalysts associated with three major types of catalytic processes. Consideration was given to the known components of the solid catalysts and any metals that were likely deposited onto them during use. A total of 180 analytical results were included in this analysis, representing 13 personal and 54 area samples. Of the long-term personal samples, airborne concentrations of metals ranged from refinery and perhaps other modern refineries during the timeframe examined. Copyright © 2011 Elsevier GmbH. All rights reserved.

Influence of chemical disorder on energy dissipation and defect evolution in concentrated solid solution alloys

International Nuclear Information System (INIS)

Zhang, Yanwen; Wang, Lumin; Caro, Alfredo; Weber, William J.; Univ. of Tennessee, Knoxville, TN

2015-01-01

A long-standing objective in materials research is to understand how energy is dissipated in both the electronic and atomic subsystems in irradiated materials, and how related non-equilibrium processes may affect defect dynamics and microstructure evolution. Here we show that alloy complexity in concentrated solid solution alloys having both an increasing number of principal elements and altered concentrations of specific elements can lead to substantial reduction in the electron mean free path and thermal conductivity, which has a significant impact on energy dissipation and consequentially on defect evolution during ion irradiation. Enhanced radiation resistance with increasing complexity from pure nickel to binary and to more complex quaternary solid solutions is observed under ion irradiation up to an average damage level of 1 displacement per atom. Understanding how materials properties can be tailored by alloy complexity and their influence on defect dynamics may pave the way for new principles for the design of radiation tolerant structural alloys

Influence of mixing and solid concentration on sodium bicarbonate secondary nucleation rate in stirred tank

Energy Technology Data Exchange (ETDEWEB)

Wylock, C.; Debaste, F.; Haut, B. [Transfers, Interfaces and Processes - Chemical Engineering Unit, ULB, Brussels (Belgium); Gutierrez, V.; Delplancke-Ogletree, M.P. [Chemicals and Materials Department, ULB, Brussels (Belgium); Cartage, T. [Solvay SA, Brussels (Belgium)

2010-09-15

This work aims to investigate the influence of the solid concentration in suspension on the contact secondary nucleation rate of sodium bicarbonate crystallization in a stirred tank crystallizer and to show the necessity of a local description of the mixing for a nucleation rate influence study. Experiments and computational fluid dynamics (CFD) simulations are realized. Crystallization kinetic parameters are extracted from experimental data using a mass distribution fitting approach. CFD and the experimental results allow identifying that a mixing property correlated with the measurements of the secondary nucleation rate in the stirred tank crystallizer appears to be the turbulent dissipation rate on the edge of the impeller. Its influence and the influence of the solid concentration in the suspension on the secondary nucleation rate are estimated by the evaluation of their exponents in a kinetic law. The obtained exponent values are then discussed qualitatively. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Sensing dissolved sediment porewater concentrations of persistent and bioaccumulative poolutants using disposable solid-phase microextraction fibers

NARCIS (Netherlands)

Mayer, P.; Vaes, W.H.J.; Wijnker, F.; Legierse, K.C.H.M.; Kraaij, R.H.; Tolls, J.; Hermens, J.L.M.

2000-01-01

Polymer coated glass fibers were applied as disposable samplers to measure dissolved concentrations of persistent and bioaccumulative pollutants (PBPs) in sediment porewater. The method is called matrix solid-phase microextraction (matrix-SPME), because it utilizes the entire sediment matrix as a

The solid molecular hydrogens in the ordered state as function of density and ortho-para concentration: a far infrared study

International Nuclear Information System (INIS)

Jochemsen, R.

1978-01-01

In this thesis, the results of far infrared absorption experiments on solid molecular hydrogen and deuterium are presented. In Chapter I an introduction to the properties of solid molecular hydrogens in given. The experimental system used for the high pressure infrared measurements and the data handling procedures are discussed in Chapter II. The theory of infrared absorption and the averaging of the dipole moment over the motion of the molecules is contained in Chapter III. In this chapter a general sum rule for the integrated absorption is derived. The remaining chapters present the results of the measurements and the discussion. In Chapter IV the author concentrates on the phonon frequencies as a function of ortho-para concentration and density, while in Chapter V measuremtns of phonon lineshape and integrated absorption intensities are presented. Finally, in Chapter VI, a study is given of the phase transition in solid hydrogen and deuterium. This study provides accurate values for the transition temperature as a function of density (in deuterium) and as a function of ortho-para concentration (in hydrogen) as well as the dependence of the order parameter on the temperature and the ortho-para concentration. (Auth.)

Influence of solids concentration on the sedimentation rate of the mud in the aggregate industry

Directory of Open Access Journals (Sweden)

Benigno Leyva-de la Cruz

2016-12-01

Full Text Available The objective of this investigation is to determine, for the mud resulting from the wash process in the Jobo community arid industry in Sagua de Tánamo, the impact of solids percent on the theoretical sedimentation velocity that is predicted by the Stokes velocity Law. Samples of the discharge pipeline and the mud sedimentation area were analyzed from granulometric, density and solids concentration points of view. The solids percentage variable (S was analyzed in four scenarios (4, 12, 20 and 28 % and time (t was evaluated at intervals of 20 minutes for 5 hours. The behavior of mud sedimentation was characterized through the sedimentation velocity. The results indicate that the Stokes velocity law does not apply for estimating the mud sedimentation velocity with a 95% confidence. Therefore, a correction function is obtained for the Stokes velocity law expressed through the polynomial mathematical model of second degree.

Threshold-dependent sample sizes for selenium assessment with stream fish tissue

Science.gov (United States)

Hitt, Nathaniel P.; Smith, David R.

2015-01-01

Natural resource managers are developing assessments of selenium (Se) contamination in freshwater ecosystems based on fish tissue concentrations. We evaluated the effects of sample size (i.e., number of fish per site) on the probability of correctly detecting mean whole-body Se values above a range of potential management thresholds. We modeled Se concentrations as gamma distributions with shape and scale parameters fitting an empirical mean-to-variance relationship in data from southwestern West Virginia, USA (63 collections, 382 individuals). We used parametric bootstrapping techniques to calculate statistical power as the probability of detecting true mean concentrations up to 3 mg Se/kg above management thresholds ranging from 4 to 8 mg Se/kg. Sample sizes required to achieve 80% power varied as a function of management thresholds and Type I error tolerance (α). Higher thresholds required more samples than lower thresholds because populations were more heterogeneous at higher mean Se levels. For instance, to assess a management threshold of 4 mg Se/kg, a sample of eight fish could detect an increase of approximately 1 mg Se/kg with 80% power (given α = 0.05), but this sample size would be unable to detect such an increase from a management threshold of 8 mg Se/kg with more than a coin-flip probability. Increasing α decreased sample size requirements to detect above-threshold mean Se concentrations with 80% power. For instance, at an α-level of 0.05, an 8-fish sample could detect an increase of approximately 2 units above a threshold of 8 mg Se/kg with 80% power, but when α was relaxed to 0.2, this sample size was more sensitive to increasing mean Se concentrations, allowing detection of an increase of approximately 1.2 units with equivalent power. Combining individuals into 2- and 4-fish composite samples for laboratory analysis did not decrease power because the reduced number of laboratory samples was compensated for by increased

Waste activated sludge fermentation: effect of solids retention time and biomass concentration.

Science.gov (United States)

Yuan, Q; Sparling, R; Oleszkiewicz, J A

2009-12-01

Laboratory scale, room temperature, semi-continuous reactors were set-up to investigate the effect of solids retention time (SRT, equal to HRT hydraulic retention time) and biomass concentration on generation of volatile fatty acids (VFA) from the non-methanogenic fermentation of waste activated sludge (WAS) originating from an enhanced biological phosphorus removal process. It was found that VFA yields increased with SRT. At the longest SRT (10d), improved biomass degradation resulted in the highest soluble to total COD ratio and the highest VFA yield from the influent COD (0.14g VFA-COD/g TCOD). It was also observed that under the same SRT, VFA yields increased when the biomass concentration decreased. At a 10d SRT the VFA yield increased by 46%, when the biomass concentration decreased from 13g/L to 4.8g/L. Relatively high nutrient release was observed during fermentation. The average phosphorus release was 17.3mg PO(4)-P/g TCOD and nitrogen release was 25.8mg NH(4)-N/g TCOD.

Inhibitory effect of high NH{sub 4}{sup +}–N concentration on anaerobic biotreatment of fresh leachate from a municipal solid waste incineration plant

Energy Technology Data Exchange (ETDEWEB)

Liu, Zhao; Dang, Yan; Li, Caihua; Sun, Dezhi, E-mail: sdzlab@126.com

2015-09-15

Highlights: • High NH{sub 4}{sup +}–N concentrations inhibit anaerobic treatment of leachate. • Inhibitory effect of NH{sub 4}{sup +}–N concentrations on anaerobic granular sludge is reversible. • High NH{sub 4}{sup +}–N concentrations inhibit bioactivities of microorganisms instead of survival. - Abstract: Fresh leachate from municipal solid waste (MSW) incineration plants generally contains extremely high NH{sub 4}{sup +}–N concentration which could inhibit the bioactivity of microorganisms. The inhibitory effect of high NH{sub 4}{sup +}–N concentration on anaerobic biotreatment of fresh leachate from a MSW incineration plant in China has been investigated in this study. The inhibition processes was studied by both static tests and a laboratory-scale expanded granular sludge bed (EGSB) reactor. The specific methanogenic activity (SMA) of the microorganisms in anaerobic granular sludge was inhibited with the NH{sub 4}{sup +}–N concentration increasing to 1000 mg/L in static tests. As well the chemical oxygen demand (COD) removal efficiency and the methane yield decreased in the EGSB reactor, while the volatile fatty acids (VFAs) accumulated and extracellular polymeric substances (EPS) of the anaerobic granular sludge increased with NH{sub 4}{sup +}–N concentration rising to 1000 mg/L, without any rebounding during 30 days of operation. Decreasing NH{sub 4}{sup +}–N concentration to 500 mg/L in influent, the COD removal efficiency recovered to about 85% after 26 days. 1000 mg/L of NH{sub 4}{sup +}–N in leachate was suggested to be the inhibition threshold in EGSB reactor. High-throughput sequencing results showed little changes in microbial communities of the sludge for a high NH{sub 4}{sup +}–N concentration, indicating that the survival of most microorganisms was not affected under such a condition. It inhibited the bioactivity of the microorganisms, resulting in decrease of the COD removal efficiency.

Indoor concentrations of nitrogen dioxide and sulfur dioxide from burning solid fuels for cooking and heating in Yunnan Province, China

NARCIS (Netherlands)

Seow, Wei Jie; Downward, George S; Wei, Hu; Rothman, Nathaniel; Reiss, Boris; Xu, Jun; Bassig, Bryan A; Li, Jihua; He, Jun; Hosgood, H Dean; Wu, Guoping; Chapman, Robert S; Tian, Linwei; Wei, Fusheng; Caporaso, Neil E; Vermeulen, Roel; Lan, Qing

2016-01-01

The Chinese national pollution census has indicated that the domestic burning of solid fuels is an important contributor to nitrogen dioxide (NO2 ) and sulfur dioxide (SO2 ) emissions in China. To characterize indoor NO2 and SO2 air concentrations in relation to solid fuel use and stove ventilation

Two percolation thresholds due to geometrical effects: experimental and simulated results

International Nuclear Information System (INIS)

Nettelblad, B; Martensson, E; Oenneby, C; Gaefvert, U; Gustafsson, A

2003-01-01

The electrical properties of a mixture of ethylene-propylene-diene monomer rubber and silicon carbide (SiC) have been measured as a function of filler concentration. It was found that mixtures containing angular SiC grains have a conductivity that displays not one, but two percolation thresholds. Different types of contacts between the conducting particles, being represented by edge and face connections, respectively, can explain the phenomenon. The two percolation thresholds are obtained at volume fractions of about 0.25 and 0.40, respectively. These values are higher than those predicted by theory, which can be explained by dispersion effects with only one phase being granular and the other being continuous. The value of the conductivity at the central plateau was found to be close to the geometric mean of the limiting conductivities at low and high concentrations. This is in good agreement with theory. With rounded SiC grains only one threshold is obtained, which is consistent with only one type of contact. The concentration dependence of the conductivity was simulated using a three-dimensional impedance network model that incorporates both edge and face contacts. The double-threshold behaviour also appears in the calculations. By dispersing the conducting particles more evenly than random, the thresholds are shifted towards higher concentrations as observed in the experiments

Assessment of suspended solids concentration in highway runoff and its treatment implication.

Science.gov (United States)

Hallberg, M; Renman, G

2006-09-01

It is understood that the major pollution from storm water is related to the content of particulate matter. One treatment practice is based on the first flush, i.e. detention of the initial part of the runoff that is considered to contain the highest concentrations of pollutants. This study has evaluated the concentration of total suspended solids in 30 consecutive runoff events during the winter season for an area of 6.7 hectares. A six-lane highway (E4) that has an annual average daily traffic load of 120,000 dominates the area and road de-icing salt (NaCl) and studded tires were in regular use during the studied period. The effluent standard for wastewater of 60 mg TSS per litre applied in EU was used to assess the treatment requirement of storm water. In only two of the events the event mean concentration was below 60 mg 1(-1). In four runoff events a partial event mean concentration below 60 mg 1(-1) was found, in 26 %, 12 %, 11 %, and 2 % respectively of the runoff volume. This would suggest that a capture of the initial part of the runoff for subsequent treatment is less applicable in this type of urban watershed.

Spot size and pulse number dependence of femtosecond laser ablation thresholds of silicon and stainless steel

Energy Technology Data Exchange (ETDEWEB)

Armbruster, Oskar; Naghilou, Aida [University of Vienna, Department of Physical Chemistry, Währinger Straße 42, A-1090 Vienna (Austria); Kitzler, Markus [TU Wien, Photonics Institute, Gusshausstraße 27-29, A-1040 Vienna (Austria); Kautek, Wolfgang, E-mail: wolfgang.kautek@univie.ac.at [University of Vienna, Department of Physical Chemistry, Währinger Straße 42, A-1090 Vienna (Austria)

2017-02-28

Highlights: • Influence of laser spot size and pulse number on the ablation of solids. • An extended defect model describes the dependence of the threshold fluence on the basis of high and low density defects. • Successfully applied to silicon and stainless steel. - Abstract: Laser spot size and pulse number are two major parameters influencing the ablation of solids. The extended defect model describes the dependence of the threshold fluence on the basis of high and low density defects. This model was successfully applied to silicon and stainless steel. It is demonstrated that heat accumulation cannot describe the experimental results.

Minimum alveolar concentration threshold of sevoflurane for postoperative dream recall.

Science.gov (United States)

Aceto, P; Perilli, V; Lai, C; Sacco, T; Modesti, C; Luca, E; De Santis, P; Sollazzi, L; Antonelli, M

2015-11-01

Many factors affect postoperative dream recall, including patient characteristics, type of anesthesia, timing of postoperative interview and stress hormone secretion. Aims of the study were to determine whether Bispectral Index (BIS)-guided anesthesia might decrease sevoflurane minimum alveolar concentration (MAC) when compared with hemodynamically-guided anesthesia, and to search for a MAC threshold useful for preventing arousal, dream recall and implicit memory. One hundred thirty patients undergoing elective thyroidectomy were enrolled. Anesthesia was induced with propofol 2 mg kg(-1), fentanyl 3 mcg kg(-1) and cis-atracurium 0.15 mg kg(-1). For anesthesia maintenance, patients were randomly assigned to one of two groups: a BIS-guided group in which sevoflurane MAC was adjusted on the basis of BIS values, and a hemodynamic parameters (HP)-guided group in which MAC was adjusted based on HP. An auditory recording was presented to patients during anesthesia maintenance. Dream recall and explicit/implicit memory were investigated upon awakening and approximately after 24 h. Mean sevoflurane MAC during auditory presentation was similar in the two groups (0.85 ± 0.16 and 0.87 ± 0.17 [P = 0.53] in BIS-guided and HP-guided groups, respectively). Frequency of dream recall was similar in the two groups: 27% (N. = 17) in BIS-guided group, 18% (N. = 12) in HP-guided group, P = 0.37. In both groups, dream recall was less probable in patients anesthetized with MAC values ≥ 0.9 (area under ROC curve = 0.83, sensitivity = 90%, and specificity = 49%). BIS-guided anesthesia was not able to generate different MAC values compared to HP-guided anesthesia. Independent of the guide used for anesthesia, a sevoflurane MAC over 0.9 was required to prevent postoperative dream recall.

Two-phase air-solid stationary turbulent flow in a cylindrical tube, with a high massive concentration

International Nuclear Information System (INIS)

Fortier, Andre; Chen, Che Pen

1976-01-01

The momentum theorem, applied separately to the two phases (fluid and solid particles), together with the equations of continuity, gives two differential equations by which the pressure and the concentration along the longitudinal profile x can be computed. These equations can be obtained by introduction of several averaging procedures of physical significance. These quantities are defined in a simple manner for the general case. Using experimental measurements of solid particle velocities in a horizontal tube by radio-tracers, it is shown how to determine the three average coefficients: Λsub(g) friction coefficient of gas, Λsub(s) momentum loss coefficient of solid particles by impacts, against the wall, and Csub(D) drag coefficient due to the velocity difference between the two phases. This determination is based on the numerical solution of the two differential equations conveniently simplified [fr

Statistical Analysis of SSMIS Sea Ice Concentration Threshold at the Arctic Sea Ice Edge during Summer Based on MODIS and Ship-Based Observational Data.

Science.gov (United States)

Ji, Qing; Li, Fei; Pang, Xiaoping; Luo, Cong

2018-04-05

The threshold of sea ice concentration (SIC) is the basis for accurately calculating sea ice extent based on passive microwave (PM) remote sensing data. However, the PM SIC threshold at the sea ice edge used in previous studies and released sea ice products has not always been consistent. To explore the representable value of the PM SIC threshold corresponding on average to the position of the Arctic sea ice edge during summer in recent years, we extracted sea ice edge boundaries from the Moderate-resolution Imaging Spectroradiometer (MODIS) sea ice product (MOD29 with a spatial resolution of 1 km), MODIS images (250 m), and sea ice ship-based observation points (1 km) during the fifth (CHINARE-2012) and sixth (CHINARE-2014) Chinese National Arctic Research Expeditions, and made an overlay and comparison analysis with PM SIC derived from Special Sensor Microwave Imager Sounder (SSMIS, with a spatial resolution of 25 km) in the summer of 2012 and 2014. Results showed that the average SSMIS SIC threshold at the Arctic sea ice edge based on ice-water boundary lines extracted from MOD29 was 33%, which was higher than that of the commonly used 15% discriminant threshold. The average SIC threshold at sea ice edge based on ice-water boundary lines extracted by visual interpretation from four scenes of the MODIS image was 35% when compared to the average value of 36% from the MOD29 extracted ice edge pixels for the same days. The average SIC of 31% at the sea ice edge points extracted from ship-based observations also confirmed that choosing around 30% as the SIC threshold during summer is recommended for sea ice extent calculations based on SSMIS PM data. These results can provide a reference for further studying the variation of sea ice under the rapidly changing Arctic.

Phase transition of DNA-linked gold nanoparticles: Creation of a high concentration of atomic hydrogen in impurity-helium solids

International Nuclear Information System (INIS)

Kiselev, S.I.; Khmelenko, V.V.; Bernard, E.P.; Lee, C.Y.; Lee, D.M.

2003-01-01

The exchange tunneling reactions D+H 2 →HD+H and D+HD→D 2 +H were used to generate high concentrations of atomic hydrogen in impurity-helium solids. The dependence of atom concentration on the content of hydrogen in the injected gas mixture gave a maximum concentration of 7.5x10 17 cm -3 hydrogen atoms for an initial gas ratio H 2 :D 2 :He=1:4:100

Drug Concentration Thresholds Predictive of Therapy Failure and Death in Children With Tuberculosis: Bread Crumb Trails in Random Forests.

Science.gov (United States)

Swaminathan, Soumya; Pasipanodya, Jotam G; Ramachandran, Geetha; Hemanth Kumar, A K; Srivastava, Shashikant; Deshpande, Devyani; Nuermberger, Eric; Gumbo, Tawanda

2016-11-01

 The role of drug concentrations in clinical outcomes in children with tuberculosis is unclear. Target concentrations for dose optimization are unknown.  Plasma drug concentrations measured in Indian children with tuberculosis were modeled using compartmental pharmacokinetic analyses. The children were followed until end of therapy to ascertain therapy failure or death. An ensemble of artificial intelligence algorithms, including random forests, was used to identify predictors of clinical outcome from among 30 clinical, laboratory, and pharmacokinetic variables.  Among the 143 children with known outcomes, there was high between-child variability of isoniazid, rifampin, and pyrazinamide concentrations: 110 (77%) completed therapy, 24 (17%) failed therapy, and 9 (6%) died. The main predictors of therapy failure or death were a pyrazinamide peak concentration <38.10 mg/L and rifampin peak concentration <3.01 mg/L. The relative risk of these poor outcomes below these peak concentration thresholds was 3.64 (95% confidence interval [CI], 2.28-5.83). Isoniazid had concentration-dependent antagonism with rifampin and pyrazinamide, with an adjusted odds ratio for therapy failure of 3.00 (95% CI, 2.08-4.33) in antagonism concentration range. In regard to death alone as an outcome, the same drug concentrations, plus z scores (indicators of malnutrition), and age <3 years, were highly ranked predictors. In children <3 years old, isoniazid 0- to 24-hour area under the concentration-time curve <11.95 mg/L × hour and/or rifampin peak <3.10 mg/L were the best predictors of therapy failure, with relative risk of 3.43 (95% CI, .99-11.82).  We have identified new antibiotic target concentrations, which are potential biomarkers associated with treatment failure and death in children with tuberculosis. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.

Influence of thresholding in mass and entropy dimension of 3-D soil images

Directory of Open Access Journals (Sweden)

A. M. Tarquis

2008-11-01

Full Text Available With the advent of modern non-destructive tomography techniques, there have been many attempts to analyze 3-D pore space features mainly concentrating on soil structure. This analysis opens a challenging opportunity to develop techniques for quantifying and describe pore space properties, one of them being fractal analysis.

Undisturbed soil samples were collected from four horizons of Brazilian soil and 3-D images at 45 μm resolution. Four different threshold criteria were used to transform computed tomography (CT grey-scale imagery into binary imagery (pore/solid to estimate their mass fractal dimension (D_m and entropy dimension (D₁. Each threshold criteria had a direct influence on the porosity obtained, varying from 8 to 24% in one of the samples, and on the fractal dimensions. Linear scaling was observed over all the cube sizes, however depending on the range of cube sizes used in the analysis, D_m could vary from 3.00 to 2.20, realizing that the threshold influenced mainly the scaling in the smallest cubes (length of size from 1 to 16 voxels.

D_m and D₁ showed a logarithmic relation with the apparent porosity in the image, however, the increase of both values respect to porosity defined a characteristic feature for each horizon that can be related to soil texture and depth.

Threshold changes in rat brain docosahexaenoic acid incorporation and concentration following graded reductions in dietary alpha-linolenic acid

Science.gov (United States)

Taha, Ameer Y.; Chang, Lisa; Chen, Mei

2016-01-01

Background This study tested the dietary level of alpha-linolenic acid (α-LNA, 18:3n-3) sufficient to maintain brain 14C-Docosahexaenoic acid (DHA, 22:6n-3) metabolism and concentration following graded α-LNA reduction. Methods 18–21 day male Fischer-344 (CDF) rats were randomized to the AIN-93G diet containing as a % of total fatty acids, 4.6% (“n-3 adequate”), 3.6%, 2.7%, 0.9% or 0.2% (“n-3 deficient”) α-LNA for 15 weeks. Rats were intravenously infused with 14C-DHA to steady state for 5 minutes, serial blood samples collected to obtain plasma and brains excised following microwave fixation. Labeled and unlabeled DHA concentrations were measured in plasma and brain to calculate the incorporation coefficient, k*, and incorporation rate, Jin. Results Compared to 4.6% α-LNA controls, k* was significantly increased in ethanolamine glycerophospholipids in the 0.2% α-LNA group. Circulating unesterified DHA and brain incorporation rates (Jin) were significantly reduced at 0.2% α-LNA. Brain total lipid and phospholipid DHA concentrations were reduced at or below 0.9% α-LNA. Conclusion Threshold changes for brain DHA metabolism and concentration were maintained at or below 0.9% dietary α-LNA, suggesting the presence of homeostatic mechanisms to maintain brain DHA metabolism when dietary α-LNA intake is low. PMID:26869088

Thermodynamic properties of solid H2 at intermediate orthohydrogen concentration

International Nuclear Information System (INIS)

Haase, D.G.; Perrell, L.R.

1983-01-01

The authors measured the specific heat of solid hydrogen samples grown under vapor pressure for orthohydrogen molar concentrations 0.65 < X < 0.2 and between 1 and 0.15 K. A thermal relaxation technique was used for the measurements to negate the heating effect of orthohydrogen conversion and to allow examination of long time heat release. The specific heat results showed no transitions or permanence which might be associated with a glass phase, with one exception. It was found that all relaxations were exponential with a single time constant regardless of sample thermal history. Measurements were made of samples isothermally converted at T = 0.3K from the ordered fcc phase to the hcp phase, in which case a gradual disorientation of the rotational moments is seen despite the relatively sharp fcc to hcp structural transition. 14 references, 5 figures

Co-digestion of ruminal content and blood from slaughterhouse industries: influence of solid concentration and ammonium generation.

Science.gov (United States)

López, I; Passeggi, M; Borzacconi, L

2006-01-01

At the present time, organic solid wastes from industries and agricultural activities are considered to be promising substrates for biogas production via anaerobic digestion. Moreover solids stabilisation is required before reutilization or disposal. Slaughterhouses are among the most important industries in Uruguay and produce 150,000 tons of ruminal content (RC) and 30,000 tons of blood per year. In order to determine the influence of the solids and blood contents, the ammonia inhibition and the inoculum adaptation co-digestion batch tests were performed. A set of experiences with TS concentration of 2.5%, 5% and 7.5% and different ratios of RC/blood were carried out using an inoculum from an UASB reactor. In all experiences fast blood hydrolisation was observed. A higher methane production was detected in the experiences with higher TS content. However, the fraction of solids degradation was lower in these experiences. A plateau in the biogas production was found. The free ammonia level, which was above the reported inhibitory levels, could explain this behaviour. After the inhibition period the biogas production restarted probably due to the biomass acclimatisation to the ammonia. In order to determine the inoculum adaptation a new experiment was performed. The inoculum used was the sludge coming from the first set of experiences. Based upon batch tests a 3.5 m3 pilot reactor was designed and started up. Ammonia inhibition was avoided by the start-up strategy and in two weeks the biogas production was 3.5 m3/d. The VS stabilisation with a solid retention time of 20 days was of 43%. The pilot reactor working at steady state had a TS concentration of 3-4% with a ratio of RC/blood of 10:1 at the entrance.

Routine determination of sulfonylurea, imidazolinone, and sulfonamide herbicides at nanogram-per-liter concentrations by solid-phase extraction and liquid chromatography/mass spectrometry

Science.gov (United States)

Furlong, E.T.; Burkhardt, M.R.; Gates, Paul M.; Werner, S.L.; Battaglin, W.A.

2000-01-01

Sulfonylurea (SU), imidazolinone (IMI), and sulfonamide (SA) herbicides are new classes of low-application-rate herbicides increasingly used by farmers. Some of these herbicides affect both weed and crop species at low dosages and must be carefully used. Less is known about the effect of these compounds on non-crop plant species, but a concentration of 100 ng/l in water has been proposed as the threshold for possible plant toxicity for most of these herbicides. Hence, analytical methods must be capable of detecting SUs, IMIs, and SAs at concentrations less than 100 ng/l in ambient water samples. The authors developed a two-cartridge, solid-phase extraction method for isolating 12 SU, 3 IMI, and 1 SA herbicides by using high-performance liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS) to identify and quantify these herbicides to 10 ng/l. This method was used to analyze 196 surface- and ground-water samples collected from May to August 1998 throughout the Midwestern United States, and more than 100 quality-assurance and quality-control samples. During the 16 weeks of the study, the HPLC/ESI-MS maintained excellent calibration linearity across the calibration range from 5 to 500 ng/l, with correlation coefficients of 0.9975 or greater. Continuing calibration verification standards at 100-ng/l concentration were analyzed throughout the study, and the average measured concentrations for individual herbicides ranged from 93 to 100 ng/l. Recovery of herbicides from 27 reagent-water samples spiked at 50 and 100 ng/l ranged from 39 to 92%, and averaged 73%. The standard deviation of recoveries ranged from 14 to 26%, and averaged 20%. This variability reflects multiple instruments, operators, and the use of automated and manual sample preparation. Spiked environmental water samples had similar recoveries, although for some herbicides, the sample matrix enhanced recoveries by as much as 200% greater than the spiked concentration. This matrix

Low-threshold conical microcavity dye lasers

DEFF Research Database (Denmark)

Grossmann, Tobias; Schleede, Simone; Hauser, Mario

2010-01-01

element simulations confirm that lasing occurs in whispering gallery modes which corresponds well to the measured multimode laser-emission. The effect of dye concentration on lasing threshold and lasing wavelength is investigated and can be explained using a standard dye laser model....

Climatic thresholds for concentrations of minerals and heavy metals in Argentinean soybeans

Science.gov (United States)

Mineral undernourishment is of concern throughout the world, and plant-derived foods are considered a major dietary source contributing to adequate daily mineral intake. Soybeans and soy ingredients are consumed daily by humans and animals. In this study, we demonstrate the climate thresholds for op...

Characterization of fluidization regime in circulating fluidized bed reactor with high solid particle concentration using computational fluid dynamics

Energy Technology Data Exchange (ETDEWEB)

Chalermsinsuwan, Benjapon; Thummakul, Theeranan; Piumsomboon, Pornpote [Chulalongkorn University, Bangkok (Thailand); Gidaspow, Dimitri [Armour College of Engineering, Chicago (United States)

2014-02-15

The hydrodynamics inside a high solid particle concentration circulating fluidized bed reactor was investigated using computational fluid dynamics simulation. Compared to a low solid particle reactor, all the conventional fluidization regimes were observed. In addition, two unconventional fluidization regimes, circulating-turbulent and dense suspension bypassing regimes, were found with only primary gas injection. The circulating-turbulent fluidization regime showed uniformly dense solid particle distribution in all the system directions, while the dense suspension bypassing fluidization regime exhibited the flow of solid particles at only one side system wall. Then, comprehensive fluidization regime clarification and mapping were evaluated using in-depth system parameters. In the circulating-turbulent fluidization regime, the total granular temperature was low compared to the adjacent fluidization regimes. In the dense suspension bypassing fluidization regime, the highest total granular temperature was obtained. The circulating-turbulent and dense suspension bypassing fluidization regimes are suitable for sorption and transportation applications, respectively.

Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

Energy Technology Data Exchange (ETDEWEB)

Tayebi, Davoud

1999-12-31

This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

Simultaneous measurement of local particle movement, solids concentrations and bubble properties in fluidized bed reactors using a novel fiber optical technique

Energy Technology Data Exchange (ETDEWEB)

Tayebi, Davoud

1998-12-31

This thesis develops a new method for simultaneous measurements of local flow properties in highly concentrated multiphase flow systems such as gas-solid fluidized bed reactors. The method is based on fiber optical technique and tracer particles. A particle present in the measuring volume in front of the probe is marked with a fluorescent dye. A light source illuminates the particles and the detecting fibres receive reflected light from uncoated particles and fluorescent light from the tracer particle. Using optical filters, the fluorescent light can be distinguished and together with a small fraction of background light from uncoated particles can be used for determination of local flow properties. Using this method, one can simultaneously measure the local movement of a single tracer particle, local bubble properties and the local solids volume fractions in different positions in the bed. The method is independent of the physical properties of the tracer particles. It is also independent of the local solids concentrations in the range of 0 to 60 vol.-%, but is mainly designed for highly concentrated flow systems. A computer programme that uses good signals from at least three sensors simultaneously to calculate the tracer particle velocity in two dimensions have been developed. It also calculates the bubble properties and local solids volume fractions from the same time series. 251 refs., 150 figs., 5 tabs.

Long-time cavitation threshold of silica water mixture under acoustic drive

Science.gov (United States)

Bussonniére, Adrien; Liu, Qingxia; Tsai, Peichun Amy

2017-11-01

The low cavitation threshold of water observed experimentally has been attributed to the presence of pre-existing tiny bubbles stabilized by impurities. However, the origin and stability of these cavitation nuclei remain unresolved. We therefore investigate the long-time cavitation evolution of water seeded with micron-sized silica particles under the influences of several parameters. Experimentally, cavitation is induced by a High Intensity Focused Ultrasound and subsequently detected by monitoring the backscattered sound. Degassed or aerated solutions of different concentrations are subjected to acoustic pulses (with the amplitude ranging from 0.1 to 1.7 MPa and a fixed repetition frequency between 0.1 and 6.5 Hz). The cavitation threshold was measured by fitting the cavitation probability curve, averaged over 1000 pulses. Surprisingly, our results shown that the cavitation threshold stabilizes at a reproducible value after a few thousand pulses. Moreover, this long-time threshold was found to decrease with increasing particle concentration, pulse period, and initial oxygen level. In contrast to the depletion of nuclei expected under long acoustic cavitation, the results suggest stabilized nuclei population depending on concentration, oxygen level, and driving period.

Effect of temperature on the plastic zone in near-threshold fatigue crack propagation in Nb-H alloys

International Nuclear Information System (INIS)

Lin, C.C.; Polvanich, N.; Salama, K.

1987-01-01

The effect of temperature on the formation of plastic zone in near-threshold fatigue crack propagation is investigated in niobium-hydrogen alloys. The study was made with the ultimate goal of determining the role of hydrogen related to test temperatures on the embrittlement and fracture processes of niobium. Fatigue tests were performed at the two temperatures 220 and 350 K on a hydrogen-free specimen as well as specimens containing hydrogen in solid solution and in the form of hydride. Microhardness was measured on the fatigued specimens in order to determine the plastic zone size at positions where the crack propagation was in the near-threshold region. The results show that at both temperatures, the plastic zone size in hydrogen-free niobium decreases as the amount of hydrogen is increased until it reaches a minimum value and then increases as the amount of hydrogen is further increased. The hydrogen concentrations at the minimum plastic zone are found to be approximately equal to those where the maximum embrittlement occurs for each temperature

Disaggregated energy consumption and GDP in Taiwan: A threshold co-integration analysis

International Nuclear Information System (INIS)

Hu, J.-L.; Lin, C.-H.

2008-01-01

Energy consumption growth is much higher than economic growth for Taiwan in recent years, worsening its energy efficiency. This paper provides a solid explanation by examining the equilibrium relationship between GDP and disaggregated energy consumption under a non-linear framework. The threshold co-integration test developed with asymmetric dynamic adjusting processes proposed by Hansen and Seo [Hansen, B.E., Seo, B., 2002. Testing for two-regime threshold cointegration in vector error-correction models. Journal of Econometrics 110, 293-318.] is applied. Non-linear co-integrations between GDP and disaggregated energy consumptions are confirmed except for oil consumption. The two-regime vector error-correction models (VECM) show that the adjustment process of energy consumption toward equilibrium is highly persistent when an appropriately threshold is reached. There is mean-reverting behavior when the threshold is reached, making aggregate and disaggregated energy consumptions grow faster than GDP in Taiwan

Sensing sulfur oxides and other sulfur bearing pollutants with solid electrolyte pellets. I. Gas concentration cells

Energy Technology Data Exchange (ETDEWEB)

Chamberland, A M; Gauthier, J M

1977-01-01

A new sensing technique using a solid electrolyte has been demonstrated for sulfur-bearing pollutants. Based on potentiometric measurements across a pellet of potassium sulfate, this sensor allows concentrations of sulfur dioxides, sulfur trioxide, hydrogen sulfide, methyl mercaptan and carbonyl sulfide in air to be measured with accuracy. Its operational concentration range at the present time is 0.1 ppM up to at least 10,000 ppM. The presence of other common pollutants such as carbon dioxide, methane, nitric oxide and nitrogen dioxide does not interfere with the measurement of air samples containing sulfur-bearing pollutants.

Effect of mixture ratio, solids concentration and hydraulic retention time on the anaerobic digestion of the organic fraction of municipal solid waste.

Science.gov (United States)

Fongsatitkul, Prayoon; Elefsiniotis, Panagiotis; Wareham, David G

2010-09-01

This paper describes how the degradation of the organic fraction of municipal solid waste (OFMSW) is affected through codigestion with varying amounts of return activated sludge (RAS). Solid waste that had its inorganic fraction selectively removed was mixed with RAS in ratios of 100% OFMSW, 50% OFMSW/50% RAS, and 25% OFMSW/75% RAS. The total solids (TS) concentration was held at 8% and three anaerobic digester systems treating the mixtures were held (for the first run) at a total hydraulic retention time (HRT) of 28 days. Increasing amounts of RAS did not however improve the mixture's digestability, as indicated by little change and/or a drop in the main performance indices [including percentage volatile solids (VS) removal and specific gas production]. The optimum ratio in this research therefore appeared to be 100% OFMSW with an associated 85.1 ± 0.6% VS removal and 0.72 ± 0.01 L total gas g(- 1) VS. In the second run, the effect of increasing percentage of TS (8, 12% and 15%) at a system HRT of 28 days was observed to yield no improvement in the main performance indices (i.e. percentage VS removal and specific gas production). Finally, during the third run, variations in the total system HRT were investigated at an 8% TS, again using 100% OFMSW. Of the HRTs explored (23, 28 and 33 days), the longest HRT yielded the best performance overall, particularly in terms of specific gas production (0.77 ± 0.01 L total gas g(-1) VS).

Digital image processing based mass flow rate measurement of gas/solid two-phase flow

Energy Technology Data Exchange (ETDEWEB)

Song Ding; Peng Lihui; Lu Geng; Yang Shiyuan [Tsinghua National Laboratory for Information Science and Technology, Department of Automation, Tsinghua University, Beijing, 100084 (China); Yan Yong, E-mail: lihuipeng@tsinghua.edu.c [University of Kent, Canterbury, Kent CT2 7NT (United Kingdom)

2009-02-01

With the rapid growth of the process industry, pneumatic conveying as a tool for the transportation of a wide variety of pulverized and granular materials has become widespread. In order to improve plant control and operational efficiency, it is essential to know the parameters of the particle flow. This paper presents a digital imaging based method which is capable of measuring multiple flow parameters, including volumetric concentration, velocity and mass flow rate of particles in the gas/solid two phase flow. The measurement system consists of a solid state laser for illumination, a low-cost CCD camera for particle image acquisition and a microcomputer with bespoke software for particle image processing. The measurements of particle velocity and volumetric concentration share the same sensing hardware but use different exposure time and different image processing methods. By controlling the exposure time of the camera a clear image and a motion blurred image are obtained respectively. The clear image is thresholded by OTSU method to identify the particles from the dark background so that the volumetric concentration is determined by calculating the ratio between the particle area and the total area. Particle velocity is derived from the motion blur length, which is estimated from the motion blurred images by using the travelling wave equation method. The mass flow rate of particles is calculated by combining the particle velocity and volumetric concentration. Simulation and experiment results indicate that the proposed method is promising for the measurement of multiple parameters of gas/solid two-phase flow.

Digital image processing based mass flow rate measurement of gas/solid two-phase flow

International Nuclear Information System (INIS)

Song Ding; Peng Lihui; Lu Geng; Yang Shiyuan; Yan Yong

2009-01-01

With the rapid growth of the process industry, pneumatic conveying as a tool for the transportation of a wide variety of pulverized and granular materials has become widespread. In order to improve plant control and operational efficiency, it is essential to know the parameters of the particle flow. This paper presents a digital imaging based method which is capable of measuring multiple flow parameters, including volumetric concentration, velocity and mass flow rate of particles in the gas/solid two phase flow. The measurement system consists of a solid state laser for illumination, a low-cost CCD camera for particle image acquisition and a microcomputer with bespoke software for particle image processing. The measurements of particle velocity and volumetric concentration share the same sensing hardware but use different exposure time and different image processing methods. By controlling the exposure time of the camera a clear image and a motion blurred image are obtained respectively. The clear image is thresholded by OTSU method to identify the particles from the dark background so that the volumetric concentration is determined by calculating the ratio between the particle area and the total area. Particle velocity is derived from the motion blur length, which is estimated from the motion blurred images by using the travelling wave equation method. The mass flow rate of particles is calculated by combining the particle velocity and volumetric concentration. Simulation and experiment results indicate that the proposed method is promising for the measurement of multiple parameters of gas/solid two-phase flow.

Determination of negligible concentration threshold values for water pollution assessment; Ableitung von Geringfuegigkeitsschwellen zur Beurteilung von Grundwasserverunreinigungen. T. 2. Organische Parameter

Energy Technology Data Exchange (ETDEWEB)

Trenck, K.T. von der [Landesanstalt fuer Umweltschutz Baden-Wuerttemberg, Karlsruhe (Germany); Roeder, R.; Slama, H. [Bayerische Landesanstalt fuer Wasserforschung (BayLWF), Muenchen (Germany); Markard, C.; Kuehl, C. [Umweltbundesamt, Berlin (Germany)

1999-12-01

Part I of the status report contains the derivation criteria, the reasons for the inorganic parameters chosen, and explanations of terms and abbreviations. A table is presented which contains negligible concentration threshold values for selected parameters of inorganic and organic substances. [German] Der erste Teil des Statusberichts enthaelt eine ausfuehrliche Darstellung der Ableitungskriterien sowie die Begruendung fuer die anorganischen Parameter und Erlaeuterungen zu den Abkuerzungen und Begriffen. Entsprechende Konzentrationswerte fuer die Geringfuegigkeitsschwellen einer Auswahl an Parametern enthaelt eine in der vorliegenden Arbeit aufgefuehrte Tabelle getrennt nach anorganischen und organischen Stoffen. (orig.)

Solid-state laser pumping with a planar compound parabolic concentrator.

Science.gov (United States)

Panteli, D V; Pani, B M; Beli, L Z

1997-10-20

A novel solid-state laser-pumping scheme is proposed that combines a reflective lamp chamber and a compound parabolic concentrator (CPC) as a light guide. The CPC is made of a transparent material of high refractive index, and light is guided by the total internal reflection, with drastically reduced reflection losses. Material is chosen so that the absorption losses are minimized in the pumping wavelength range. The lamp chamber is designed with the principles of nonimaging optics, which ensures that the radiation is efficiently transferred from the lamp to the input aperture of the CPC. The pumping efficiency was first estimated theoretically, which gave us enough justification for the more accurate calculations with ray tracing. Single as well as multiple pumping cavities are discussed. New pumping geometry results in significantly increased pumping efficiency compared with conventional geometries. Also the lamp and the laser rod are separated, leading to reduced thermal load. We found that the proposed pumping method is also applicable to diode-pumped lasers.

Intraoperative transfusion threshold and tissue oxygenation

DEFF Research Database (Denmark)

Nielsen, K; Dahl, B; Johansson, P I

2012-01-01

Transfusion with allogeneic red blood cells (RBCs) may be needed to maintain oxygen delivery during major surgery, but the appropriate haemoglobin (Hb) concentration threshold has not been well established. We hypothesised that a higher level of Hb would be associated with improved subcutaneous...... oxygen tension during major spinal surgery....

Non-affine fields in solid-solid transformations: the structure and stability of a product droplet.

Science.gov (United States)

Paul, Arya; Sengupta, Surajit; Rao, Madan

2014-01-08

We describe the microstructure, morphology, and dynamics of growth of a droplet of martensite nucleating in a parent austenite during a solid-solid transformation, using a Landau theory written in terms of both conventional affine elastic deformations and non-affine deformations. Non-affineness, φ, serves as a source of strain incompatibility and screens long-ranged elastic interactions. It is produced wherever the local stress exceeds a threshold and anneals diffusively thereafter. Using a variational calculation, we find three types of stable solution (labeled I, II, and III) for the structure of the product droplet, depending on the stress threshold and the scaled mobilities of φ parallel and perpendicular to the parent-product interface. The profile of the non-affine field φ is different in these three solutions: I is characterized by a vanishingly small φ, II admits large values of φ localized in regions of high stress within the parent-product interface, and III is a structure in which φ completely wets the parent-product interface. The width l and size W of the twins follow the relation l is proportional to √W in solution I; this relation does not hold for II or III. We obtain a dynamical phase diagram featuring these solutions, and argue that they represent specific solid-state microstructures.

A method to quantify infectious airborne pathogens at concentrations below the threshold of quantification by culture

Science.gov (United States)

Cutler, Timothy D.; Wang, Chong; Hoff, Steven J.; Zimmerman, Jeffrey J.

2013-01-01

In aerobiology, dose-response studies are used to estimate the risk of infection to a susceptible host presented by exposure to a specific dose of an airborne pathogen. In the research setting, host- and pathogen-specific factors that affect the dose-response continuum can be accounted for by experimental design, but the requirement to precisely determine the dose of infectious pathogen to which the host was exposed is often challenging. By definition, quantification of viable airborne pathogens is based on the culture of micro-organisms, but some airborne pathogens are transmissible at concentrations below the threshold of quantification by culture. In this paper we present an approach to the calculation of exposure dose at microbiologically unquantifiable levels using an application of the “continuous-stirred tank reactor (CSTR) model” and the validation of this approach using rhodamine B dye as a surrogate for aerosolized microbial pathogens in a dynamic aerosol toroid (DAT). PMID:24082399

Characterization of naproxen-loaded solid SMEDDSs prepared by spray drying: the effect of the polysaccharide carrier and naproxen concentration.

Science.gov (United States)

Čerpnjak, Katja; Zvonar, Alenka; Vrečer, Franc; Gašperlin, Mirjana

2015-05-15

The purpose of this study was to prepare solid SMEDDS (sSMEDDS) particles produced by spray-drying using maltodextrin (MD), hypromellose (HPMC), and a combination of the two as a solid carrier. Naproxen (NPX) as the model drug was dissolved (at 6% concentration) or partially suspended (at 18% concentration) in a liquid SMEDDS composed of Miglyol(®) 812, Peceol™, Gelucire(®) 44/14, and Solutol(®) HS 15. Among the sSMEDDSs tested, the MD-based sSMEDDSs (with a granular, smooth-surfaced, microspherical appearance) preserved the self-microemulsifying properties of liquid SMEDDSs and exhibited dissolution profiles similar to those of liquid SMEDDSs, irrespective of the concentration of NPX. In contrast, HPMC-based sSMEDDSs (irregular-shaped microparticles) exhibited slightly prolonged release times due to the polymeric nature of the carrier. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and Raman mapping analysis confirmed molecularly dissolved NPX (at 6% of drug loading), whereas at 18% NPX loading drug is partially molecularly dissolved and partially in the crystalline state. Copyright © 2015. Published by Elsevier B.V.

Perioperative transfusion threshold and ambulation after hip revision surgery

DEFF Research Database (Denmark)

Nielsen, Kamilla; Johansson, Pär I; Dahl, Benny

2014-01-01

BACKGROUND: Transfusion with red blood cells (RBC) may be needed during hip revision surgery but the appropriate haemoglobin concentration (Hb) threshold for transfusion has not been well established. We hypothesized that a higher transfusion threshold would improve ambulation after hip revision...... surgery. METHODS: The trial was registered at Clinicaltrials.gov ( NCT00906295). Sixty-six patients aged 18 years or older undergoing hip revision surgery were randomized to receive RBC at a Hb threshold of either 7.3 g/dL (restrictive group) or 8.9 g/dL (liberal group). Postoperative ambulation...... received RBC. CONCLUSIONS: A Hb transfusion threshold of 8.9 g/dL was associated with a statistically significantly faster TUG after hip revision surgery compared to a threshold of 7.3 g/dL but the clinical importance is questionable and the groups did not differ in Hb at the time of testing....

Solidification of liquid concentrate and solid waste generated as by-products of the liquid radwaste treatment systems in light-water reactors

International Nuclear Information System (INIS)

Neilson, R.M. Jr.; Colombo, P.

1977-01-01

The treatment of liquid concentrate and solid waste produced in light-water reactors as by-products of liquid radwaste treatment systems consists of five basic operations: waste collection, waste pretreatment, solidification agent handling, mixing/packaging (solidification) and waste package handling. This paper will concern itself primarily with the solidification operation, however, the other operations enumerated as well as the types of wastes treated and their origins will be briefly described, especially with regards to their effects on solidification. During solidification, liquid concentrate and solid wastes are incorporated with a solidification agent to form a monolithic, free-standing solid. The basic solidification agent types either currently used in the United States or proposed for use include absorbants, hydraulic cement, urea-formaldehyde, other polymer systems, and bitumen. The operation, formulations and limitations of these agents as used for radwaste solidification will be discussed. Properties relevant to the evaluation of solidified waste forms will be identified and relative comparisons made for wastes solidified by various processes

Effect of particle size ratio on the conducting percolation threshold of granular conductive-insulating composites

International Nuclear Information System (INIS)

He Da; Ekere, N N

2004-01-01

In this paper, we apply Monte Carlo simulation to investigate the conductive percolation threshold of granular composite of conductive and insulating powders with amorphous structure. We focus on the effect of insulating to conductive particle size ratio λ = d i /d c on the conducting percolation threshold p c (the volume fraction of the conductive powder). Simulation results show that, for λ = 1, the percolation threshold p c lies between simple cubic and body centred cubic site percolation thresholds, and that as λ increases the percolation threshold decreases. We also use the structural information obtained by the simulation to study the nonlinear current-voltage characteristics of composite with solid volume fraction of conductive powder below p c in terms of electron tunnelling for nanoscale powders, dielectric breakdown for microscale or larger powders, and pressing induced conduction for non-rigid insulating powders

Factors influencing suspended solids concentrations in activated sludge settling tanks.

Science.gov (United States)

Kim, Y; Pipes, W O

1999-05-31

A significant fraction of the total mass of sludge in an activated sludge process may be in the settling tanks if the sludge has a high sludge volume index (SVI) or when a hydraulic overload occurs during a rainstorm. Under those conditions, an accurate estimate of the amount of sludge in the settling tanks is needed in order to calculate the mean cell residence time or to determine the capacity of the settling tanks to store sludge. Determination of the amount of sludge in the settling tanks requires estimation of the average concentration of suspended solids in the layer of sludge (XSB) in the bottom of the settling tanks. A widely used reference recommends averaging the concentrations of suspended solids in the mixed liquor (X) and in the underflow (Xu) from the settling tanks (XSB=0. 5{X+Xu}). This method does not take into consideration other pertinent information available to an operator. This is a report of a field study which had the objective of developing a more accurate method for estimation of the XSB in the bottom of the settling tanks. By correlation analysis, it was found that only 44% of the variation in the measured XSB is related to sum of X and Xu. XSB is also influenced by the SVI, the zone settling velocity at X and the overflow and underflow rates of the settling tanks. The method of averaging X and Xu tends to overestimate the XSB. A new empirical estimation technique for XSB was developed. The estimation technique uses dimensionless ratios; i.e., the ratio of XSB to Xu, the ratio of the overflow rate to the sum of the underflow rate and the initial settling velocity of the mixed liquor and sludge compaction expressed as a ratio (dimensionless SVI). The empirical model is compared with the method of averaging X and Xu for the entire range of sludge depths in the settling tanks and for SVI values between 100 and 300 ml/g. Since the empirical model uses dimensionless ratios, the regression parameters are also dimensionless and the model can be

The Applicability of the Distribution Coefficient, KD, Based on Non-Aggregated Particulate Samples from Lakes with Low Suspended Solids Concentrations.

Directory of Open Access Journals (Sweden)

Aine Marie Gormley-Gallagher

Full Text Available Separate phases of metal partitioning behaviour in freshwater lakes that receive varying degrees of atmospheric contamination and have low concentrations of suspended solids were investigated to determine the applicability of the distribution coefficient, KD. Concentrations of Pb, Ni, Co, Cu, Cd, Cr, Hg and Mn were determined using a combination of filtration methods, bulk sample collection and digestion and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS. Phytoplankton biomass, suspended solids concentrations and the organic content of the sediment were also analysed. By distinguishing between the phytoplankton and (inorganic lake sediment, transient variations in KD were observed. Suspended solids concentrations over the 6-month sampling campaign showed no correlation with the KD (n = 15 for each metal, p > 0.05 for Mn (r2 = 0.0063, Cu (r2 = 0.0002, Cr (r2 = 0.021, Ni (r2 = 0.0023, Cd (r2 = 0.00001, Co (r2 = 0.096, Hg (r2 = 0.116 or Pb (r2 = 0.164. The results implied that colloidal matter had less opportunity to increase the dissolved (filter passing fraction, which inhibited the spurious lowering of KD. The findings conform to the increasingly documented theory that the use of KD in modelling may mask true information on metal partitioning behaviour. The root mean square error of prediction between the directly measured total metal concentrations and those modelled based on the separate phase fractions were ± 3.40, 0.06, 0.02, 0.03, 0.44, 484.31, 80.97 and 0.1 μg/L for Pb, Cd, Mn, Cu, Hg, Ni, Cr and Co respectively. The magnitude of error suggests that the separate phase models for Mn and Cu can be used in distribution or partitioning models for these metals in lake water.

A new temperature threshold detector - Application to missile monitoring

Science.gov (United States)

Coston, C. J.; Higgins, E. V.

Comprehensive thermal surveys within the case of solid propellant ballistic missile flight motors are highly desirable. For example, a problem involving motor failures due to insulator cracking at motor ignition, which took several years to solve, could have been identified immediately on the basis of a suitable thermal survey. Using conventional point measurements, such as those utilizing typical thermocouples, for such a survey on a full scale motor is not feasible because of the great number of sensors and measurements required. An alternate approach recognizes that temperatures below a threshold (which depends on the material being monitored) are acceptable, but higher temperatures exceed design margins. In this case hot spots can be located by a grid of wire-like sensors which are sensitive to temperature above the threshold anywhere along the sensor. A new type of temperature threshold detector is being developed for flight missile use. The considered device consists of KNO3 separating copper and Constantan metals. Above the KNO3 MP, galvanic action provides a voltage output of a few tenths of a volt.

Continuous adjustment of threshold voltage in carbon nanotube field-effect transistors through gate engineering

Science.gov (United States)

Zhong, Donglai; Zhao, Chenyi; Liu, Lijun; Zhang, Zhiyong; Peng, Lian-Mao

2018-04-01

In this letter, we report a gate engineering method to adjust threshold voltage of carbon nanotube (CNT) based field-effect transistors (FETs) continuously in a wide range, which makes the application of CNT FETs especially in digital integrated circuits (ICs) easier. Top-gated FETs are fabricated using solution-processed CNT network films with stacking Pd and Sc films as gate electrodes. By decreasing the thickness of the lower layer metal (Pd) from 20 nm to zero, the effective work function of the gate decreases, thus tuning the threshold voltage (Vt) of CNT FETs from -1.0 V to 0.2 V. The continuous adjustment of threshold voltage through gate engineering lays a solid foundation for multi-threshold technology in CNT based ICs, which then can simultaneously provide high performance and low power circuit modules on one chip.

Retinal hemorrhage thresholds for Q-switched neodymium-Yag laser exposures

Energy Technology Data Exchange (ETDEWEB)

Blankenstein, M.F.; Zuclich, J.; Allen, R.G.; Davis, H.; Thomas, S.J.; Harrison, R.F.

1986-07-01

Thresholds for retinal vitreal and contained hemorrhages were determined for 1064 nm laser light at 30-nsec and 4-nsec pulsewidths. Rhesus monkeys received graded exposures from a neodymium-yag laser onto either the macular or extramacular region of the retina. Contained hemorrhages appeared as concentric ring structures with white punctate centers. The vitreal hemorrhage was characterized by the presence of choroidal blood in the vitreal chamber at the exposure site. The 30-nsec contained hemorrhage threshold (ED50) was 1.7 mJ on the macula and 2.1 mJ for an extramacular exposure. The 30-nsec vitreal hemorrhage macular threshold was 2.3 mJ, and the extramacular threshold was 6.6 mJ. The threshold for the 4-nsec pulsewidths to produce a hemorrhage (vitreal or contained) on the retina (macula or extramacular) was 340 microJ.

Retinal-hemorrhage thresholds for Q-switched neodymium-YAG laser exposures

Energy Technology Data Exchange (ETDEWEB)

Blankenstein, M.F.; Zuclich; Allen, R.G.; Davis; Thomas, S.J.

1986-07-01

Thresholds for retinal vitreal and contained hemorrhages were determined for 1064-nm laser light at 30-ns and 4-ns pulsewidths. Rhesus monkeys received graded exposures from a neodymium-YAG laser onto either the macular or extramacular region of the retina. Contained hemorrhages appeared as concentric-ring structures with white punctuate centers. The vitreal hemorrhage was characterized by the presence of choroidal blood in the vitreal chamber at the exposure site. The 30-ns contained-hemorrhage threshold (ED50) was 1.7 mJ on the macula and 2.1 mJ for an extramacular exposure. The 30-ns vitreal-hemorrhage macular threshold was 2.3 mJ, and the extramacular threshold was 6.6 Mj. The threshold for the 4-ns pulse widths to produce a hemorrhage (vitreal or contained) on the retina (macula or extramacular) was 340 uJ.

Cost effectiveness of below-threshold waste disposal at DOE sites

International Nuclear Information System (INIS)

Wickham, L.E.; Smith, C.F.; Cohen, J.J.

1986-01-01

Previous study has indicated the feasibility of establishing a threshold of concentration below which certain low-level (radioactive wastes) (LLW) could be safely handled and disposed of by conventional means such as landfills. Such below-threshold wastes have been synonymously termed de minimis or below regulatory concern (BRC) and can be deemed appropriate for management according to their nonradiological characteristics. The objective of this study was to determine the cost effectiveness for management and disposal of below-threshold waste at certain US Department of Energy sites. The sites selected for this study were the Idaho National Engineering Laboratory and Savannah River Laboratory. Cost-benefit analysis was used to determine the impacts, benefits, and potential cost advantages of establishing and implementing a threshold limit

An Evaluation of a Dual Coriolis Meter System for In-Line Monitoring of Suspended Solids Concentrations in Radioactive Slurries

International Nuclear Information System (INIS)

Hylton, T.D.

2000-01-01

The U.S. Department of Energy (DOE) has millions of gallons of radioactive liquid and sludge wastes stored in underground tanks at several of its sites. In order to comply with various regulations and to circumvent potential problems associated with tank integrity, these wastes must be retrieved from the tanks, transferred to treatment facilities (or other storage locations), and processed to stable waste forms. The sludge wastes will typically be mobilized by some mechanical means (e.g., mixer pump, submerged jet) and mixed with the respective supernatants to create slurries that can be transferred by pipeline to the desired destination. Depending on the DOE site, these slurries may be transferred up to six miles. Since the wastes are radioactive, it is critically important for the transfers to be made without plugging a pipeline. To reduce such a risk, the relevant properties of the slurry (e.g., density, suspended solids concentration, viscosity, and particle size distribution) should be determined to be within acceptable limits prior to transfer. These properties should also be continuously monitored and controlled within specified limits while the transfer is in progress. The baseline method for determining the transport properties of slurries involves sampling and analysis; however, this method is time-consuming, and costly, and it does not provide real-time information. In addition, personnel who collect and analyze the samples are exposed to radiation. It is also questionable as to whether a laboratory analyst can obtain representative aliquots from the sample jar for these solid-liquid mixtures. The alternative method for determining the transport properties is in-line analysis. An in-line instrument is one that is connected to the process, analyzes the slurry as it flows through or by the instrument, and provides the results within seconds. This instrument can provide immediate feedback to operators so that, when necessary, the operators can respond

Observation of LPI Thresholds for the Nike Laser

Science.gov (United States)

Weaver, J. L.; Oh, J.; Afeyan, B.; Charbonneau-Lefort, M.; Phillips, L.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S.; Schmitt, A. J.; Feldman, U.; Holland, G.; Lehmberg, R. H.; McLean, E.; Manka, C.

2008-11-01

The Nike laser is being used to study thresholds for laser plasma instabilities (LPI) at intensities (10^15-10^16 W/cm^2) relevant to advanced implosion designs for direct drive inertial confinement fusion. The combination of short wavelength (248 nm), large bandwidth (1-2 THz), and beam smoothing by induced spatial incoherence available with this krypton-fluoride laser make these experiments unique among current facilities. This talk will present an overview of results with an emphasis on the two-plasmon decay instability (2φp). Measurements of x-rays and emission near ^1/2φo and ^3/2 φo harmonics of the laser wavelength have been collected over a wide range of intensities for both solid and foam targets. Data indicate collective multiple-angle driven excitation compatible with previous observations using solid planar targets.

Concentration, flux, and trend estimates with uncertainty for nutrients, chloride, and total suspended solids in tributaries of Lake Champlain, 1990–2014

Science.gov (United States)

Medalie, Laura

2016-12-20

The U.S. Geological Survey, in cooperation with the New England Interstate Water Pollution Control Commission and the Vermont Department of Environmental Conservation, estimated daily and 9-month concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids from 1990 (or first available date) through 2014 for 18 tributaries of Lake Champlain. Estimates of concentration and flux, provided separately in Medalie (2016), were made by using the Weighted Regressions on Time, Discharge, and Season (WRTDS) regression model and update previously published WRTDS model results with recent data. Assessment of progress towards meeting phosphorus-reduction goals outlined in the Lake Champlain management plan relies on annual estimates of phosphorus flux. The percent change in annual concentration and flux is provided for two time periods. The R package EGRETci was used to estimate the uncertainty of the trend estimate. Differences in model specification and function between this study and previous studies that used WRTDS to estimate concentration and flux using data from Lake Champlain tributaries are described. Winter data were too sparse and nonrepresentative to use for estimates of concentration and flux but were sufficient for estimating the percentage of total annual flux over the period of record. Median winter-to-annual fractions ranged between 21 percent for total suspended solids and 27 percent for dissolved phosphorus. The winter contribution was largest for all constituents from the Mettawee River and smallest from the Ausable River. For the full record (1991 through 2014 for total and dissolved phosphorus and chloride and 1993 through 2014 for nitrogen and total suspended solids), 6 tributaries had decreasing trends in concentrations of total phosphorus, and 12 had increasing trends; concentrations of dissolved phosphorus decreased in 6 and increased in 8 tributaries; fluxes of total phosphorus decreased in 5 and

Prediction of ore fluid metal concentrations from solid solution concentrations in ore-stage calcite: Application to the Illinois-Kentucky and Central Tennessee Mississippi Valley-type districts

Science.gov (United States)

Smith-Schmitz, Sarah E.; Appold, Martin S.

2018-03-01

Knowledge of the concentrations of Zn and Pb in Mississippi Valley-type (MVT) ore fluids is fundamental to understanding MVT deposit origin. Most previous attempts to quantify the concentrations of Zn and Pb in MVT ore fluids have focused on the analysis of fluid inclusions. However, these attempts have yielded ambiguous results due to possible contamination from secondary fluid inclusions, interferences from Zn and Pb in the host mineral matrix, and uncertainties about whether the measured Zn and Pb signals represent aqueous solute or accidental solid inclusions entrained within the fluid inclusions. The purpose of the present study, therefore, was to try to determine Zn and Pb concentrations in MVT ore fluids using an alternate method that avoids these ambiguities by calculating Zn and Pb concentrations in MVT ore fluids theoretically based on their solid solution concentrations in calcite. This method was applied to the Illinois-Kentucky and Central Tennessee districts, which both contain ore-stage calcite. Experimental partition coefficient (D) values from Rimstidt et al. (1998) and Tsusue and Holland (1966), and theoretical thermodynamic distribution coefficient (KD) values were employed in the present study. Ore fluid concentrations of Zn were likely most accurately predicted by Rimstidt et al. (1998) D values, based on their success in predicting known fluid inclusion concentrations of Mg and Mn, and likely also most accurately predicted ore fluid concentrations of Fe. All four of these elements have a divalent ionic radius smaller than that of Ca2+ and form carbonate minerals with the calcite structure. For both the Illinois-Kentucky and the Central Tennessee district, predicted ore fluid Zn and Fe concentrations were on the order of up to 10's of ppm. Ore fluid concentrations of Pb could only be predicted using Rimstidt et al. (1998) D values. However, these concentrations are unlikely to be reliable, as predicted ore fluid concentrations of Sr and Ba

Specific features of concentrated phase under decomposition of weak solid /sup 3/He-/sup 4/He solution

Energy Technology Data Exchange (ETDEWEB)

Mikheev, V A; Majdamov, V A; Kal' noj, S E; Omelaenko, N I

1988-06-01

The decomposition of solid /sup 3/He-/sup 4/He solutuions is studied on the samples 0.54% /sup 3/He(V=20.55 cm/sup 3//mole) and 0.60% /sup 4/He (V=24.04-24.93 cm/sup 3//mole) using pulse NMR method. At T=100 mK the decomposition of a weak solution proceeds more than for 30 h, the decomposition rate and temperature being dependent on the sample prehistory. In the concentrated phase of the decomposed weak solution the spin diffraction of /sup 3/He is of the quasi-one-dimensional character with the diffusion coefficient D /similar to/ 10/sup -5/ cm/sup 2//sec typical of liquid /sup 3/He and exceeding that bulk solid /sup 3/He by two orders of magnitude. The longitudinal relaxation time in the quasi-one-dimensional phase (/similar to/ 1 sec) is characteristic of the solid state and coinsides with data for bulk /sup 3/He. The temperature behaviour of magnetization in the quasi-one-dimensional phase is well described by the Curie law.

Ammonia threshold for inhibition of anaerobic digestion of thin stillage and the importance of organic loading rate.

Science.gov (United States)

Moestedt, Jan; Müller, Bettina; Westerholm, Maria; Schnürer, Anna

2016-03-01

Biogas production from nitrogen-rich feedstock results in release of ammonia (NH3), causing inhibition of the microbial process. The reported threshold ammonia value for stable biogas production varies greatly between studies, probably because of differences in operating conditions. Moreover, it is often difficult to separate the effect of ammonia inhibition from that of organic loading rate (OLR), as these two factors are often interrelated. This study attempted to distinguish the effects of ammonia and OLR by analysis of two laboratory-scale biogas reactors operating with thin stillage and subjected to an increase in free ammonia (from 0.30 to 1.1 g L(-1)) either by addition of an external nitrogen source (urea) or by increasing the OLR (3.2-6.0 g volatile solids L(-1) d(-1)). The results showed that ammonia concentration was detrimental for process performance, with the threshold for stability in both processes identified as being about 1 g NH3-N L(-1), irrespective of OLR. Analysis of the methanogenic community showed limited differences between the two reactors on order level and a clear increase in the abundance of Methanomicrobiales, particularly Methanoculleus sp., in response to increasing ammonia concentration. Further comprehensive molecular analysis revealed that diverse Methanoculleus species dominated in the reactors at a given ammonia level at different OLR. The acetogenic community was clearly affected by both ammonia concentration and OLR, suggesting that the volatile fatty acid load in relation to the higher OLR was important for the dynamics of this community. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Physico-chemical thresholds in the distribution of fish species among French lakes

Directory of Open Access Journals (Sweden)

Roubeix Vincent

2017-01-01

Full Text Available The management of lakes requires the definition of physico-chemical thresholds to be used for ecosystem preservation or restoration. According to the European Water Framework Directive, the limits between physico-chemical quality classes must be set consistently with biological quality elements. One way to do this consists in analyzing the response of aquatic communities to environmental gradients across monitoring sites and in identifying ecological community thresholds, i.e. zones in the gradients where the species turnover is the highest. In this study, fish data from 196 lakes in France were considered to derive ecological thresholds using the multivariate method of gradient forest. The analysis was performed on 25 species and 36 environmental parameters. The results revealed the highest importance of maximal water temperature in the distribution of fish species. Other important parameters included geographical factors, dissolved organic carbon concentration and water transparency, while nutrients appeared to have low influence. In spite of the diversity of species responses to the gradients, community thresholds were detected in the gradients of the most important physico-chemical parameters and of total phosphorus and nitrate concentrations as well. The thresholds identified in such macroecological study may highlight new patterns of species natural distribution and improve niche characterization. Moreover, when factors that may be influenced by human activities are involved, the thresholds could be used to set environmental standards for lake preservation.

Effect of solid waste landfill organic pollutants on groundwater in three areas of Sicily (Italy) characterized by different vulnerability.

Science.gov (United States)

Indelicato, Serena; Orecchio, Santino; Avellone, Giuseppe; Bellomo, Sergio; Ceraulo, Leopoldo; Di Leonardo, Rossella; Di Stefano, Vita; Favara, Rocco; Candela, Esterina Gagliano; La Pica, Leonardo; Morici, Sabina; Pecoraino, Giovannella; Pisciotta, Antonino; Scaletta, Claudio; Vita, Fabio; Vizzini, Salvatrice; Bongiorno, David

2017-07-01

The aim of this study was to obtain information on the presence and levels of hazardous organic pollutants in groundwater located close to solid waste landfills. Eighty-two environmental contaminants, including 16 polycyclic aromatic hydrocarbons (PAHs), 20 volatile organic compounds (VOCs), 29 polychlorinated biphenyls (PCBs), 7 dioxins (polychlorinated dibenzo-p-dioxins, PCDDs) and 10 furans (polychlorinated dibenzofurans, PCDFs) were monitored in areas characterised by different geological environments surrounding three municipal solid waste landfills (Palermo, Siculiana and Ragusa) in Sicily (Italy) in three sampling campaigns. The total concentrations of the 16 PAHs were always below the legal threshold. Overall, the Fl/Fl + Py diagnostic ratio revealed that PAHs had a petrogenic origin. VOC levels, except for two notable exceptions near Palermo landfill, were always below the legal limit. As concerns PCB levels, several samples were found positive with levels exceeding the legal limits. It is worth noting that the % PCB distribution differs from that of commercial compositions. In parallel, some samples of groundwater containing PCDDs and PCDFs exceeding the legal threshold were also found. Among the 17 congeners monitored, the most abundant were the highest molecular weight ones.

Threshold quantum cryptography

International Nuclear Information System (INIS)

Tokunaga, Yuuki; Okamoto, Tatsuaki; Imoto, Nobuyuki

2005-01-01

We present the concept of threshold collaborative unitary transformation or threshold quantum cryptography, which is a kind of quantum version of threshold cryptography. Threshold quantum cryptography states that classical shared secrets are distributed to several parties and a subset of them, whose number is greater than a threshold, collaborates to compute a quantum cryptographic function, while keeping each share secretly inside each party. The shared secrets are reusable if no cheating is detected. As a concrete example of this concept, we show a distributed protocol (with threshold) of conjugate coding

Suspended Solids Profiler Shop Test Report

International Nuclear Information System (INIS)

STAEHR, T.W.

2000-01-01

The Suspended Solids Profiler (SSP) Instrument is planned to be installed in the AZ-101 tank to measure suspended solids concentrations during mixer pump testing. The SSP sensor uses a reflectance measurement principle to determine the suspended solids concentrations. The purpose of this test is to provide a documented means of verifying that the functional components of the SSP operate properly

Dislocation glide in Ni-Al solid solutions from the atomic scale up: a molecular dynamics study

International Nuclear Information System (INIS)

Rodary, E.

2003-01-01

The glide of an edge dislocation in solid solutions is studied by molecular dynamics, at fixed temperature and imposed external stress. We have optimized an EAM potential for Ni(1 a 8% A1): it well reproduces the lattice expansion, local atomic order, stacking fault energy as a function of composition, as well as the elastic properties of the γ' phase with L1 2 structure. On increasing the stress, the dislocation is first immobile, then glides with a velocity proportional to the stress and the velocity saturates on reaching the transverse sound velocity. However, only beyond a static threshold stress, σ s , does the dislocation glide a distance large enough to allow macroscopic shear; the linear part of the velocity-stress curve extrapolates to zero at a dynamical threshold stress, σ d , The friction coefficient, and the threshold stresses (σ s and σ d ), increase with the A1 concentration and decrease with temperature (300 and 500 K). Close to the critical shear stress, σ s , the dislocation glide is analysed with a 'stop and go' model. The latter yields the flight velocity between obstacles, the mean obstacle density and the distribution of the waiting time on each obstacle as a function of stress, composition and temperature. The obstacle to the glide is proposed to be the strong repulsion between Al atoms brought into nearest neighbour position by the glide process, and not the dislocation-solute interaction. The microscopic parameters so defined are introduced into a micro-mechanical model, which well reproduces the known behaviour of nickel base solid solutions. (author)

Liquid–Solid Dual-Gate Organic Transistors with Tunable Threshold Voltage for Cell Sensing

KAUST Repository

Zhang, Yu

2017-10-17

Liquid electrolyte-gated organic field effect transistors and organic electrochemical transistors have recently emerged as powerful technology platforms for sensing and simulation of living cells and organisms. For such applications, the transistors are operated at a gate voltage around or below 0.3 V because prolonged application of a higher voltage bias can lead to membrane rupturing and cell death. This constraint often prevents the operation of the transistors at their maximum transconductance or most sensitive regime. Here, we exploit a solid–liquid dual-gate organic transistor structure, where the threshold voltage of the liquid-gated conduction channel is controlled by an additional gate that is separated from the channel by a metal-oxide gate dielectric. With this design, the threshold voltage of the “sensing channel” can be linearly tuned in a voltage window exceeding 0.4 V. We have demonstrated that the dual-gate structure enables a much better sensor response to the detachment of human mesenchymal stem cells. In general, the capability of tuning the optimal sensing bias will not only improve the device performance but also broaden the material selection for cell-based organic bioelectronics.

Effect of liquid film on near-threshold laser ablation of a solid surface

Energy Technology Data Exchange (ETDEWEB)

Kim, Dongsik; Oh, Bukuk; Lee, Ho

2004-01-30

Enhancement of material ablation and photoacoustic excitation by an artificially deposited liquid film in the process of pulsed-laser ablation (PLA) is investigated in this paper. Ablation threshold, ablation rate, surface topography, and acoustic-transient emission are also measured for dry and liquid film-coated surfaces. The physical mechanisms of enhanced ablation in the liquid-assisted process are analyzed at relatively low laser fluences with negligible effect of laser-produced plasma. Particularly, correlation between material ablation and acoustic-transient generation is examined. In the experiment, aluminum thin-films and bulk foils are ablated by Q-switched Nd:YAG laser pulses. The dependence of ablation rate and laser-induced topography on liquid film thickness and chemical composition is also examined. Photoacoustic emission is measured by the probe beam deflection method utilizing a CW HeNe laser and a microphone. In comparison with a dry ablation process, the liquid-assisted ablation process results in substantially augmented ablation efficiency and reduced ablation threshold. The results indicate that both increased laser-energy coupling, i.e., lowered reflectance, and amplified photoacoustic excitation in explosive vaporization of liquid are responsible for the enhanced material ablation.

Threshold values characterizing iodine-induced SCC of zircaloys

International Nuclear Information System (INIS)

Une, K.

1984-01-01

Threshold values of stress, stress intensity factor, strain, strain rate and iodine concentration for SCC of unirradiated and irradiated Zircaloys are reviewed. The ratio of σsub(th)/σsub(y) adequately represents the effects of cold work and irradiation damage on the SCC susceptibility, where threshold stress σsub(th) is defined as the minimum stress to cause SCC to failure after -6 and 10 -3 min -1 . A comparison of SCC data between constant strain rate and constant stress tests is presented in order to examine the validity of a cumulative-damage concept under SCC conditions. (author)

Threshold values in acquisitions in the power market

International Nuclear Information System (INIS)

2002-01-01

This report discusses weather the authorities should define threshold values for the market concentration in the power market for reasons of future competition. It is shown that special circumstances in the power market dictate that the competition authorities may have good reasons to adopt a precautionary attitude to acquisitions in that market. The assessment must consider the fact that it is the competition in individual hours that is relevant for the market. Thus the competition authorities should use threshold values based on the producers' share of the power capacity in all relevant market areas that are affected by the acquisition. The threshold values may still be used only as a first filtering out procedure. A final decision about intervention must be founded on a closer assessment of all the socioeconomic consequences of the acquisition in each case

Solubility and hydrolysis of Np(V) in dilute to concentrated alkaline NaCl solutions. Formation of Na-Np(V)-OH solid phases at 22 C

Energy Technology Data Exchange (ETDEWEB)

Petrov, Vladimir G. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; Fellhauer, David; Gaona, Xavier; Dardenne, Kathy; Rothe, Joerg; Altmaier, Marcus [Karlsruhe Institute of Technology (Germany). Inst. for Nuclear Waste Disposal; Kalmykov, Stepan N. [Lomonosov Moscow State Univ. (Russian Federation). Dept. of Chemistry; NRC Kurchatov Institute, Moscow (Russian Federation)

2017-03-01

The solubility of Np(V) was investigated at T=22±2 C in alkaline NaCl solutions of different ionic strength (0.1-5.0 M). The solid phases controlling the solubility at different -log{sub 10} m{sub H{sup +}}(pH{sub m}) and NaCl concentration were characterized by XRD, quantitative chemical analysis, SEM-EDS and XAFS (both XANES and EXAFS). Aqueous phases in equilibrium with Np(V) solids were investigated for selected samples within 8.9≤pH{sub m}≤10.3 by UV-vis/NIR absorption spectroscopy. In 0.1 M NaCl, the experimental solubility of the initial greenish NpO{sub 2}OH(am) solid phase is in good agreement with previous results obtained in NaClO{sub 4} solutions, and is consistent with model calculations for fresh NpO{sub 2}OH(am) using the thermodynamic data selection in NEA-TDB. Below pH{sub m}∝11.5 and for all NaCl concentrations studied, Np concentration in equilibrium with the solid phase remained constant during the timeframe of this study (∝2 years). This observation is in contrast to the aging of the initial NpO{sub 2}OH(am) into a more crystalline modification with the same stoichiometry, NpO{sub 2}OH(am, aged), as reported in previous studies for concentrated NaClO{sub 4} and NaCl. Instead, the greenish NpO{sub 2}OH(am) transforms into a white solid phase in those systems with [NaCl]≥1.0 M and pH{sub m}≥11.5, and into two different pinkish phases above pH{sub m}∝13.2. The solid phase transformation is accompanied by a drop in Np solubility of 0.5-2 log{sub 10}-units (depending upon NaCl concentration). XANES analyses of green, white and pink phases confirm the predominance of Np(V) in all cases. Quantitative chemical analysis shows the incorporation of Na{sup +} in the original NpO{sub 2}OH(am) material, with Na:Np ≤ 0.3 for the greenish solids and 0.8 ≤ Na:Np ≤ 1.6 for the white and pinkish phases. XRD data confirms the amorphous character of the greenish phase, whereas white and pink solids show well-defined but discrepant XRD patterns

Threshold quantities for infectious diseases in periodic environments

NARCIS (Netherlands)

Heesterbeek, J.A.P.; Roberts, M.G.

1995-01-01

In this short note we give threshold quantities that determine the stability of the infection-free steady state for periodic deterministic systems that describe the spread of infectious diseases in populations whose individuals can be divided into a finite number of distinct groups. We concentrate

Evaluating Spatial Variability in Sediment and Phosphorus Concentration-Discharge Relationships Using Bayesian Inference and Self-Organizing Maps

Science.gov (United States)

Underwood, Kristen L.; Rizzo, Donna M.; Schroth, Andrew W.; Dewoolkar, Mandar M.

2017-12-01

Given the variable biogeochemical, physical, and hydrological processes driving fluvial sediment and nutrient export, the water science and management communities need data-driven methods to identify regions prone to production and transport under variable hydrometeorological conditions. We use Bayesian analysis to segment concentration-discharge linear regression models for total suspended solids (TSS) and particulate and dissolved phosphorus (PP, DP) using 22 years of monitoring data from 18 Lake Champlain watersheds. Bayesian inference was leveraged to estimate segmented regression model parameters and identify threshold position. The identified threshold positions demonstrated a considerable range below and above the median discharge—which has been used previously as the default breakpoint in segmented regression models to discern differences between pre and post-threshold export regimes. We then applied a Self-Organizing Map (SOM), which partitioned the watersheds into clusters of TSS, PP, and DP export regimes using watershed characteristics, as well as Bayesian regression intercepts and slopes. A SOM defined two clusters of high-flux basins, one where PP flux was predominantly episodic and hydrologically driven; and another in which the sediment and nutrient sourcing and mobilization were more bimodal, resulting from both hydrologic processes at post-threshold discharges and reactive processes (e.g., nutrient cycling or lateral/vertical exchanges of fine sediment) at prethreshold discharges. A separate DP SOM defined two high-flux clusters exhibiting a bimodal concentration-discharge response, but driven by differing land use. Our novel framework shows promise as a tool with broad management application that provides insights into landscape drivers of riverine solute and sediment export.

Organic solid-state lasers

CERN Document Server

Forget, Sébastien

2013-01-01

Organic lasers are broadly tunable coherent sources, potentially compact, convenient and manufactured at low-costs. Appeared in the mid 60’s as solid-state alternatives for liquid dye lasers, they recently gained a new dimension after the demonstration of organic semiconductor lasers in the 90's. More recently, new perspectives appeared at the nanoscale, with organic polariton and surface plasmon lasers. After a brief reminder to laser physics, a first chapter exposes what makes organic solid-state organic lasers specific. The laser architectures used in organic lasers are then reviewed, with a state-of-the-art review of the performances of devices with regard to output power, threshold, lifetime, beam quality etc. A survey of the recent trends in the field is given, highlighting the latest developments with a special focus on the challenges remaining for achieving direct electrical pumping of organic semiconductor lasers. A last chapter covers the applications of organic solid-state lasers.

Cost effectiveness of below-threshold waste disposal at DOE sites

International Nuclear Information System (INIS)

Smith, C.F.; Cohen, J.J.

1987-01-01

A minimal health and environmental risk, limitations on disposal capacity, and the relatively high costs of low level waste (LLW) disposal are basic driving forces that lead to consideration of less restrictive disposal of wastes with very low levels of radiological contamination. The term threshold limit describes radioactive wastes that have sufficiently low-levels of radiological content to be managed according to their nonradiological properties. Given the efforts described elsewhere to provide guidance on the definition of below threshold (BT) doses and concentration levels, the purpose of this study was to quantify the resultant quantities, costs and cost effectiveness of BT disposal. For purposes of consistency with the previous demonstrations of the application of the threshold concept, available data for waste streams at the Idaho National Engineering Laboratory (INEL) and the Savannah River Plant (SRP) sites were collected and analyzed with regard to volumes, radionuclide concentrations, and disposal costs. From this information, quantities of BT waste, potential cost savings and cost effectiveness values were estimated. 1 reference, 5 tables

Dislocation glide in Ni-Al solid solutions from the atomic scale up: a molecular dynamics study; Etude du glissement des dislocations dans la solution solide Ni-Al par simulation a l'echelle atomique

Energy Technology Data Exchange (ETDEWEB)

Rodary, E

2003-01-01

The glide of an edge dislocation in solid solutions is studied by molecular dynamics, at fixed temperature and imposed external stress. We have optimized an EAM potential for Ni(1 a 8% A1): it well reproduces the lattice expansion, local atomic order, stacking fault energy as a function of composition, as well as the elastic properties of the {gamma}' phase with L1{sub 2} structure. On increasing the stress, the dislocation is first immobile, then glides with a velocity proportional to the stress and the velocity saturates on reaching the transverse sound velocity. However, only beyond a static threshold stress, {sigma}{sub s}, does the dislocation glide a distance large enough to allow macroscopic shear; the linear part of the velocity-stress curve extrapolates to zero at a dynamical threshold stress, {sigma}{sub d}, The friction coefficient, and the threshold stresses ({sigma}{sub s} and {sigma}{sub d}), increase with the A1 concentration and decrease with temperature (300 and 500 K). Close to the critical shear stress, {sigma}{sub s}, the dislocation glide is analysed with a 'stop and go' model. The latter yields the flight velocity between obstacles, the mean obstacle density and the distribution of the waiting time on each obstacle as a function of stress, composition and temperature. The obstacle to the glide is proposed to be the strong repulsion between Al atoms brought into nearest neighbour position by the glide process, and not the dislocation-solute interaction. The microscopic parameters so defined are introduced into a micro-mechanical model, which well reproduces the known behaviour of nickel base solid solutions. (author)

Damage resistant optics for a mega-joule solid-state laser

International Nuclear Information System (INIS)

Campbell, J.H.; Rainer, F.; Kozlowski, M.; Wolfe, C.R.; Thomas, I.; Milanovich, F.

1990-01-01

Research on Inertial Confinement Fusion (ICF) has progressed rapidly in the past several years. As a consequence, LLNL is developing plans to upgrade the current 120 kJ solid state (Nd +3 -phosphate glass) Nova laser to a 1.5 to 2 megajoule system with the goal of achieving fusion ignition. The design of the planned Nova Upgrade is briefly discussed. Because of recent improvements in the damage resistance of optical materials it is now technically and economically feasible to build a megajoule-class solid state laser. Specifically, the damage threshold of Nd +3 -doped phosphate laser glass, multilayer dielectric coatings, and non-linear optical crystals (e.g., KDP) have been dramatically improved. These materials now meet the fluence requirements for a 1.5--2 MJ Nd 3+ -glass laser operating at 1054 and 351 nm and at a pulse length of 3 ns. The recent improvements in damage thresholds are reviewed; threshold data at both 1064 and 355 nm and the measured pulse length scaling are presented. 20 refs., 9 figs., 2 tabs

Lower versus Higher Hemoglobin Threshold for Transfusion in Septic Shock

DEFF Research Database (Denmark)

Holst, Lars B; Haase, Nicolai; Wetterslev, Jørn

2014-01-01

BACKGROUND: Blood transfusions are frequently given to patients with septic shock. However, the benefits and harms of different hemoglobin thresholds for transfusion have not been established. METHODS: In this multicenter, parallel-group trial, we randomly assigned patients in the intensive care...... unit (ICU) who had septic shock and a hemoglobin concentration of 9 g per deciliter or less to receive 1 unit of leukoreduced red cells when the hemoglobin level was 7 g per deciliter or less (lower threshold) or when the level was 9 g per deciliter or less (higher threshold) during the ICU stay...... were similar in the two intervention groups. CONCLUSIONS: Among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion...

Negligible depletion solid-phase microextraction with radiolabeled analytes to study free concentrations and protein binding : an example with [3H]Estradiol

NARCIS (Netherlands)

Heringa, M.B.; Pastor, D.; Algra, J.; Vaes, W.H.J.; Hemmens, J.L.M.

2002-01-01

A new method is presented that enables sensitive measurement of free concentrations of radiolabeled ligands. Additionally, protein binding of radiochemicals in complex matrixes can be determined with this new technique that combines negligible depletion solid-phase microextraction (nd-SPME) with

Should the threshold for expired-air carbon monoxide concentration as a means of verifying self-reported smoking abstinence be reduced in clinical treatment programmes? Evidence from a Malaysian smokers' clinic.

Science.gov (United States)

Wee, Lei-Hum; West, Robert; Mariapun, Jeevitha; Chan, Caryn Mei-Hsien; Bulgiba, Awang; Peramalah, Devi; Jit, Swinder

2015-08-01

It has been proposed that the expired-air carbon monoxide (CO) threshold for confirming smoking abstinence in clinical practice be reduced below 10 ppm. Optimal thresholds may vary across regions. Data are needed to assess the impact of such a change on claimed success. A total of 253 smokers who attended the Tanglin quit smoking clinic in Malaysia were followed-up 1, 3 and 6 months after the target quit date. All participants received a standard behavioural support programme and were prescribed either varenicline or nicotine replacement therapy. Expired-air CO was measured at every visit. Respondents' smoking status was assessed using a range of different CO thresholds (3, 5 and 10 ppm) and the impact on quit rates was calculated. Predictors of success as defined using the different thresholds were assessed. The 6-month abstinence rates were: 1 month - 54.9% at 10 ppm, 54.9% at 5 ppm and 48.6% at 3 ppm; 3 months - 36.0% at 10 ppm, 35.2% at 5 ppm and 30.4% at 3 ppm; 6 months - 24.1% at 10 ppm, 24.1% at 5 ppm and 20.6% at 3 ppm. Older smokers were more likely to be recorded as abstinent at 6 months regardless of the threshold used. Reducing the threshold for expired-air carbon monoxide concentrations to verify claimed smoking abstinence from 10 ppm to 5 ppm makes minimal difference to documented success rates in Malaysian smoker's clinic patients. Reducing to 3 ppm decreases success rates slightly. Predictors of success at stopping appear to be unaffected by the threshold used. Copyright © 2015 Elsevier Ltd. All rights reserved.

Atomic and molecular effects in the VUV spectra of solids

International Nuclear Information System (INIS)

Sonntag, B.

1977-10-01

The VUV spectra of solids are often dominated by atomic or molecular effects, which clearly manifest themselves in the gross features of the spectra and the fine structure at inner shell excitation thresholds. Evidence for the influence of atomic and molecular matrix elements, multiplet-splitting and correlation is presented. Special emphasis is given to the direct experimental verification based on the comparison of atomic and solid state spectra. (orig.) [de

CARA Risk Assessment Thresholds

Science.gov (United States)

Hejduk, M. D.

2016-01-01

Warning remediation threshold (Red threshold): Pc level at which warnings are issued, and active remediation considered and usually executed. Analysis threshold (Green to Yellow threshold): Pc level at which analysis of event is indicated, including seeking additional information if warranted. Post-remediation threshold: Pc level to which remediation maneuvers are sized in order to achieve event remediation and obviate any need for immediate follow-up maneuvers. Maneuver screening threshold: Pc compliance level for routine maneuver screenings (more demanding than regular Red threshold due to additional maneuver uncertainty).

Measurement of scattering cross sections of liquid and solid hydrogen, deuterium and deuterium hydride for thermal neutrons

International Nuclear Information System (INIS)

Seiffert, W.D.

1984-01-01

The scattering cross sections for liquid and solid normal hydrogen, para-hydrogen, deuterium and deuterium hydride were measured for thermal neutrons at various temperatures. Solid samples of para-hydrogen exhibit distinct Bragg scattering. Liquid samples of deuterium and para-hydrogen also exhibit distinct coherence phenomena, which is indicative of strong local ordering of the molecules. In para-hydrogen and deuterium hydride, the threshold for scattering with excitation of rotations is distinctly visible. The positions of the thresholds show that the molecules in liquid hydrogen are not unhindered in their movement. After the beginning of the rotational excitation the scattering cross sections of liquid and solid para-hydrogen have different shapes which is to be explained by the differences in the dynamics of the liquid and the solid specimen. 22 references

Two-dimensional simulation of gas concentration impedance for a planar solid oxide fuel cell

International Nuclear Information System (INIS)

Fadaei, M.; Mohammadi, R.; Ghassemi, M.

2014-01-01

Highlights: • The 2D simulation shows another feature in concentration impedance. • The channel gas transport causes a capacitive behavior. • Anode polarization variation has a significant influence on velocity distribution. • The influence of 2D simulation is important for channel height bigger than 2 mm. - Abstract: This paper presents a two-dimensional model for a planar solid oxide fuel cell (SOFC) anode in order to simulate the steady-state performance characteristics as well as the electrochemical impedance spectra. The developed model couples the mass transport with the electrochemical kinetics. The transient conservation equations (momentum and species equations) are solved numerically and the linear kinetic is used for the anode electrochemistry. In order to solve the system of the nonlinear equations, an in-house code based on the finite volume method is developed and utilized. A parametric study is also carried out and the results are discussed. Results show a capacitive semicircle in the Nyquist plot which is identical to the gas concentration impedance. The simulation results are in good agreement with published data

Ablation by ultrashort laser pulses: Atomistic and thermodynamic analysis of the processes at the ablation threshold

International Nuclear Information System (INIS)

Upadhyay, Arun K.; Inogamov, Nail A.; Rethfeld, Baerbel; Urbassek, Herbert M.

2008-01-01

Ultrafast laser irradiation of solids may ablate material off the surface. We study this process for thin films using molecular-dynamics simulation and thermodynamic analysis. Both metals and Lennard-Jones (LJ) materials are studied. We find that despite the large difference in thermodynamical properties between these two classes of materials--e.g., for aluminum versus LJ the ratio T c /T tr of critical to triple-point temperature differs by more than a factor of 4--the values of the ablation threshold energy E abl normalized to the cohesion energy, ε abl =E abl /E coh , are surprisingly universal: all are near 0.3 with ±30% scattering. The difference in the ratio T c /T tr means that for metals the melting threshold ε m is low, ε m abl , while for LJ it is high, ε m >ε abl . This thermodynamical consideration gives a simple explanation for the difference between metals and LJ. It explains why despite the universality in ε abl , metals thermomechanically ablate always from the liquid state. This is opposite to LJ materials, which (near threshold) ablate from the solid state. Furthermore, we find that immediately below the ablation threshold, the formation of large voids (cavitation) in the irradiated material leads to a strong temporary expansion on a very slow time scale. This feature is easily distinguished from the acoustic oscillations governing the material response at smaller intensities, on the one hand, and the ablation occurring at larger intensities, on the other hand. This finding allows us to explain the puzzle of huge surface excursions found in experiments at near-threshold laser irradiation

A survey of topsoil arsenic and mercury concentrations across France.

Science.gov (United States)

Marchant, B P; Saby, N P A; Arrouays, D

2017-08-01

Even at low concentrations, the presence of arsenic and mercury in soils can lead to ecological and health impacts. The recent European-wide LUCAS Topsoil Survey found that the arsenic concentration of a large proportion of French soils exceeded a threshold which indicated that further investigation was required. A much smaller proportion of soils exceeded the corresponding threshold for mercury but the impacts of mining and industrial activities on mercury concentrations are not well understood. We use samples from the French national soil monitoring network (RMQS: Réseau de Mesures de la Qualité des Sols) to explore the variation of topsoil arsenic and mercury concentrations across mainland France at a finer spatial resolution than was reported by LUCAS Topsoil. We use geostatistical methods to map the expected concentrations of these elements in the topsoil and the probabilities that the legislative thresholds are exceeded. We find that, with the exception of some areas where the geogenic concentrations and soil adsorption capacities are very low, arsenic concentrations are generally larger than the threshold which indicates that further assessment of the area is required. The lower of two other guideline values indicating risks to ecology or health is exceeded in fewer than 5% of RMQS samples. These exceedances occur in localised hot-spots primarily associated with mining and mineralization. The probabilities of mercury concentrations exceeding the further assessment threshold value are everywhere less than 0.01 and none of the RMQS samples exceed either of the ecological and health risk thresholds. However, there are some regions with elevated concentrations which can be related to volcanic material, natural mineralizations and industrial contamination. These regions are more diffuse than the hot-spots of arsenic reflecting the greater volatility of mercury and therefore the greater ease with which it can be transported and redeposited. The maps provide a

The investigation of exposure to benzene, toluene, ethylbenzene and xylene (BTEX with Solid Phase Microextr action Method in gas station in Yazd province

Directory of Open Access Journals (Sweden)

Mohammad Hossein Mosaddegh Mehrjerdi

2014-01-01

Full Text Available Abstract Background: Benzene, toluene, ethylbenzene and xylene (BTEX are volatile organic compounds which their physical and chemical characteristics are similar. Evaporation of BTEX from gasoline in petrol station into the air causes gasoline station attendants expose to them. A new extraction method of volatile organic compounds is solid phase microextraction (SPME. The aim of this study is to optimize extraction conditions of BTEX from air samples and then determination of gasoline station air contamination with BTEX in Yazd. Material and Methods: In this study air samples were collected using Tedlar bags and then extracted and analyzed with SPME fiber and gas chromatography equipped with a flame ionization detector. Results: Our results indicate that PDMS/CAR has the best peak area in comparison with two other fibers The Optimized extraction and desorption times are estimated 3 and 1 minutes, respectively Mean concentration of benzene, toluene, ethyl benzene and xylene in gas station’s air were 1932±807, 667±405, 148±89, 340±216 µg/m3 respectively. Conclusion: Benzene mean concentration is above threshold limit value (0.5PPM. Whereas, toluene, ethylbenzene and xylene mean concentration are lower than threshold limit values.

Controlling thermal properties of dense gas fluidized beds for concentrated solar power by internal and external solids circulation

Science.gov (United States)

Ammendola, Paola; Bareschino, Piero; Chirone, Riccardo; Salatino, Piero; Solimene, Roberto

2017-06-01

Fluidization technology displays a long record of success stories, mostly related to applications to thermal and thermochemical processes, which are fostering extension to novel and relatively unexplored fields. Application of fluidized beds to collection and thermal storage of solar radiation in Concentrated Solar Power (CSP) is one of the most promising, a field which poses challenging issues and great opportunities to fluidization scientists and technologists. The potential of this growing field calls for reconsideration of some of the typical design and operation guidelines and criteria, with the goal of exploiting the inherently good thermal performances of gas-fluidized beds at their best. "Creative" and non-conventional design and operation of fluidized beds, like those based on internal and external solids circulation, may be beneficial to the enhancement of thermal diffusivity and surface-to-bed heat transfer, improving the potential for application in the very demanding context of CSP with thermal energy storage. This paper investigated: i) a fluidized bed configuration with an uneven distribution of the fluidizing gas to promote vortices in the scale of bed height (internal solids circulation); ii) a dual fluidized bed configuration characterized by an external solids circulation achieved by the operation of a riser and a bubbling fluidized bed. CFD simulations showed the hydrodynamics conditions under which the internal solids circulation was established. The hydrodynamic characterization of the external solids circulation was achieved by an experimental study carried out with different cold models. The dual fluidized bed system was optimized in terms of operating conditions and geometrical features of the connections between two fluidized beds.

Phosphatase activity tunes two-component system sensor detection threshold.

Science.gov (United States)

Landry, Brian P; Palanki, Rohan; Dyulgyarov, Nikola; Hartsough, Lucas A; Tabor, Jeffrey J

2018-04-12

Two-component systems (TCSs) are the largest family of multi-step signal transduction pathways in biology, and a major source of sensors for biotechnology. However, the input concentrations to which biosensors respond are often mismatched with application requirements. Here, we utilize a mathematical model to show that TCS detection thresholds increase with the phosphatase activity of the sensor histidine kinase. We experimentally validate this result in engineered Bacillus subtilis nitrate and E. coli aspartate TCS sensors by tuning their detection threshold up to two orders of magnitude. We go on to apply our TCS tuning method to recently described tetrathionate and thiosulfate sensors by mutating a widely conserved residue previously shown to impact phosphatase activity. Finally, we apply TCS tuning to engineer B. subtilis to sense and report a wide range of fertilizer concentrations in soil. This work will enable the engineering of tailor-made biosensors for diverse synthetic biology applications.

Laser-induced damage thresholds of gold, silver and their alloys in air and water

Energy Technology Data Exchange (ETDEWEB)

Starinskiy, Sergey V.; Shukhov, Yuri G.; Bulgakov, Alexander V., E-mail: bulgakov@itp.nsc.ru

2017-02-28

Highlights: • Laser damage thresholds of Ag, Au and Ag-Au alloys in air and water are measured. • Alloy thresholds are lower than those of Ag and Au due to low thermal conductivity. • Laser damage thresholds in water are ∼1.5 times higher than those in air. • Light scattering mechanisms responsible for high thresholds in water are suggested. • Light scattering mechanisms are supported by optical reflectance measurements. - Abstract: The nanosecond-laser-induced damage thresholds of gold, silver and gold-silver alloys of various compositions in air and water have been measured for single-shot irradiation conditions. The experimental results are analyzed theoretically by solving the heat flow equation for the samples irradiated in air and in water taking into account vapor nucleation at the solid-water interface. The damage thresholds of Au-Ag alloys are systematically lower than those for pure metals, both in air and water that is explained by lower thermal conductivities of the alloys. The thresholds measured in air agree well with the calculated melting thresholds for all samples. The damage thresholds in water are found to be considerably higher, by a factor of ∼1.5, than the corresponding thresholds in air. This cannot be explained, in the framework of the used model, neither by the conductive heat transfer to water nor by the vapor pressure effect. Possible reasons for the high damage thresholds in water such as scattering of the incident laser light by the vapor-liquid interface and the critical opalescence in the superheated water are suggested. Optical pump-probe measurements have been performed to study the reflectance dynamics of the surface irradiated in air and water. Comparison of the transient reflectance signal with the calculated nucleation dynamics provides evidence that the both suggested scattering mechanisms are likely to occur during metal ablation in water.

SIMPLE METHOD FOR ESTIMATING POLYCHLORINATED BIPHENYL CONCENTRATIONS ON SOILS AND SEDIMENTS USING SUBCRITICAL WATER EXTRACTION COUPLED WITH SOLID-PHASE MICROEXTRACTION. (R825368)

Science.gov (United States)

A rapid method for estimating polychlorinated biphenyl (PCB) concentrations in contaminated soils and sediments has been developed by coupling static subcritical water extraction with solid-phase microextraction (SPME). Soil, water, and internal standards are placed in a seale...

Updated LPI Thresholds for the Nike Laser*

Science.gov (United States)

Weaver, J. L.; Oh, J.; Afeyan, B.; Phillips, L.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S. P.; Serlin, V.; Schmitt, A. J.; Feldman, U.; Holland, G.; Manka, C.; Lehmberg, R. H.; McLean, E.

2009-11-01

Advanced implosion designs for direct drive inertial confinement fusion use high laser intensities (10^15-10^16 W/cm^2) to achieve gain (g>100) with a reduction in total laser energy (ENike laser at NRL are an attractive choice due to their combination of short wavelength (248 nm), large bandwidth (1-2 THz), and beam smoothing by induced spatial incoherence but the potential threat from laser-plasma instabilities (LPI) needs to be assessed. The 2008 LPI campaign at Nike yielded threshold intensities above 10^15 W/cm^2 for the two-plasmon instability, a value higher than reported for 351 nm glass lasers. The experiments used a planar geometry, solid polystyrene targets, and a subset of beams (E<200 J) with a reduced focal spot (d<125 μm). The 2009 campaign extended the shot parameters to higher laser energies (E<1 kJ) and larger spot sizes (d<300 μm). Spectrally-resolved and time-resolved measurements of x-rays and emission near ^1/2φo and ^3/2φo harmonics of the laser wavelength show threshold intensities consistent with the 2008 results. *Work supported by DoE/NNSA

Modeling Trace Element Concentrations in the San Francisco Bay Estuary from Remote Measurement of Suspended Solids

Science.gov (United States)

Press, J.; Broughton, J.; Kudela, R. M.

2014-12-01

Suspended and dissolved trace elements are key determinants of water quality in estuarine and coastal waters. High concentrations of trace element pollutants in the San Francisco Bay estuary necessitate consistent and thorough monitoring to mitigate adverse effects on biological systems and the contamination of water and food resources. Although existing monitoring programs collect annual in situ samples from fixed locations, models proposed by Benoit, Kudela, & Flegal (2010) enable calculation of the water column total concentration (WCT) and the water column dissolved concentration (WCD) of 14 trace elements in the San Francisco Bay from a more frequently sampled metric—suspended solids concentration (SSC). This study tests the application of these models with SSC calculated from remote sensing data, with the aim of validating a tool for continuous synoptic monitoring of trace elements in the San Francisco Bay. Using HICO imagery, semi-analytical and empirical SSC algorithms were tested against a USGS dataset. A single-band method with statistically significant linear fit (p Arsenic, Iron, and Lead in the southern region of the Bay were found to exceed EPA water quality criteria for human health and aquatic life. The results of this study demonstrate the potential of monitoring programs using remote observation of trace element concentrations, and provide the foundation for investigation of pollutant sources and pathways over time.

Stochastic Calculus: Application to Dynamic Bifurcations and Threshold Crossings

Science.gov (United States)

Jansons, Kalvis M.; Lythe, G. D.

1998-01-01

For the dynamic pitchfork bifurcation in the presence of white noise, the statistics of the last time at zero are calculated as a function of the noise level ∈ and the rate of change of the parameter μ. The threshold crossing problem used, for example, to model the firing of a single cortical neuron is considered, concentrating on quantities that may be experimentally measurable but have so far received little attention. Expressions for the statistics of pre-threshold excursions, occupation density, and last crossing time of zero are compared with results from numerical generation of paths.

Predicting molybdenum toxicity to higher plants: Estimation of toxicity threshold values

Energy Technology Data Exchange (ETDEWEB)

McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C.; Zhao, F.J.; Stroud, J.L. [Soil Science Department, Centre for Soils and Ecosystems Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Zhang, H.; Fozard, S. [Division of Environmental Science, Lancaster University, Lancaster LA1 4YQ (United Kingdom)

2010-10-15

Four plant species (oilseed rape, Brassica napus L.; red clover, Trifolium pratense L.; ryegrass, Lolium perenne L.; and tomato, Lycopersicon esculentum L.) were tested on ten soils varying widely in soil properties to assess molybdenum (Mo) toxicity. A larger range (66-fold-609-fold) of added Mo concentrations resulting in 50% inhibition of yield (ED{sub 50}) was found among soils than among plant species (2-fold-38-fold), which illustrated that the soils differed widely in the expression of Mo toxicity. Toxicity thresholds based on soil solution Mo narrowed the variation among soils compared to thresholds based on added Mo concentrations. We conclude that plant bioavailability of Mo in soil depends on Mo solubility, but this alone did not decrease the variability in observed toxicity enough to be used in risk assessment and that other soil properties influencing Mo toxicity to plants need to be considered. - Mo toxicity thresholds varied widely in different soils and therefore soil properties need to be taken into account in order to assess the risk of Mo exposure.

Influence of fiber degradation and concentration of fermentable sugars on simultaneous saccharification and fermentation of high-solids spruce slurry to ethanol.

Science.gov (United States)

Hoyer, Kerstin; Galbe, Mats; Zacchi, Guido

2013-10-08

Saccharification and fermentation of pretreated lignocellulosic materials, such as spruce, should be performed at high solids contents in order to reduce the cost of the produced bioethanol. However, this has been shown to result in reduced ethanol yields or a complete lack of ethanol production. Previous studies have shown inconsistent results when prehydrolysis is performed at a higher temperature prior to the simultaneous saccharification and fermentation (SSF) of steam-pretreated lignocellulosic materials. In some cases, a significant increase in overall ethanol yield was reported, while in others, a slight decrease in ethanol yield was observed. In order to investigate the influence of prehydrolysis on high-solids SSF of steam-pretreated spruce slurry, in the present study, the presence of fibers and inhibitors, degree of fiber degradation and initial fermentable sugar concentration has been studied. SSF of whole steam-pretreated spruce slurry at a solids content of 13.7% water-insoluble solids (WIS) resulted in a very low overall ethanol yield, mostly due to poor fermentation. The yeast was, however, able to ferment the washed slurry and the liquid fraction of the pretreated slurry. Performing prehydrolysis at 48°C for 22 hours prior to SSF of the whole pretreated slurry increased the overall ethanol yield from 3.9 to 62.1%. The initial concentration of fermentable sugars in SSF could not explain the increase in ethanol yield in SSF with prehydrolysis. Although the viscosity of the material did not appear to decrease significantly during prehydrolysis, the degradation of the fibers prior to the addition of the yeast had a positive effect on ethanol yield when using whole steam-pretreated spruce slurry. The results of the present study suggest that the increase in ethanol yield from SSF when performing prehydrolysis is a result of fiber degradation rather than a decrease in viscosity. The increased concentration of fermentable sugars at the beginning of the

Rayleigh-Taylor instability in accelerated elastic-solid slabs

Science.gov (United States)

Piriz, S. A.; Piriz, A. R.; Tahir, N. A.

2017-12-01

We develop the linear theory for the asymptotic growth of the incompressible Rayleigh-Taylor instability of an accelerated solid slab of density ρ2, shear modulus G , and thickness h , placed over a semi-infinite ideal fluid of density ρ110.1007/s000330050121] to arbitrary values of AT and unveil the singular feature of an instability threshold below which the slab is stable for any perturbation wavelength. As a consequence, an accelerated elastic-solid slab is stable if ρ2g h /G ≤2 (1 -AT) /AT .

The solid state detector technology for picosecond laser ranging

Science.gov (United States)

Prochazka, Ivan

1993-01-01

We developed an all solid state laser ranging detector technology, which makes the goal of millimeter accuracy achievable. Our design and construction philosophy is to combine the techniques of single photon ranging, ultrashort laser pulses, and fast fixed threshold discrimination while avoiding any analog signal processing within the laser ranging chain. The all solid state laser ranging detector package consists of the START detector and the STOP solid state photon counting module. Both the detectors are working in an optically triggered avalanche switching regime. The optical signal is triggering an avalanche current buildup which results in the generation of a uniform, fast risetime output pulse.

Laser-induced damage thresholds of gold, silver and their alloys in air and water

Science.gov (United States)

Starinskiy, Sergey V.; Shukhov, Yuri G.; Bulgakov, Alexander V.

2017-02-01

The nanosecond-laser-induced damage thresholds of gold, silver and gold-silver alloys of various compositions in air and water have been measured for single-shot irradiation conditions. The experimental results are analyzed theoretically by solving the heat flow equation for the samples irradiated in air and in water taking into account vapor nucleation at the solid-water interface. The damage thresholds of Au-Ag alloys are systematically lower than those for pure metals, both in air and water that is explained by lower thermal conductivities of the alloys. The thresholds measured in air agree well with the calculated melting thresholds for all samples. The damage thresholds in water are found to be considerably higher, by a factor of ∼1.5, than the corresponding thresholds in air. This cannot be explained, in the framework of the used model, neither by the conductive heat transfer to water nor by the vapor pressure effect. Possible reasons for the high damage thresholds in water such as scattering of the incident laser light by the vapor-liquid interface and the critical opalescence in the superheated water are suggested. Optical pump-probe measurements have been performed to study the reflectance dynamics of the surface irradiated in air and water. Comparison of the transient reflectance signal with the calculated nucleation dynamics provides evidence that the both suggested scattering mechanisms are likely to occur during metal ablation in water.

Theory of threshold phenomena

International Nuclear Information System (INIS)

Hategan, Cornel

2002-01-01

Theory of Threshold Phenomena in Quantum Scattering is developed in terms of Reduced Scattering Matrix. Relationships of different types of threshold anomalies both to nuclear reaction mechanisms and to nuclear reaction models are established. Magnitude of threshold effect is related to spectroscopic factor of zero-energy neutron state. The Theory of Threshold Phenomena, based on Reduced Scattering Matrix, does establish relationships between different types of threshold effects and nuclear reaction mechanisms: the cusp and non-resonant potential scattering, s-wave threshold anomaly and compound nucleus resonant scattering, p-wave anomaly and quasi-resonant scattering. A threshold anomaly related to resonant or quasi resonant scattering is enhanced provided the neutron threshold state has large spectroscopic amplitude. The Theory contains, as limit cases, Cusp Theories and also results of different nuclear reactions models as Charge Exchange, Weak Coupling, Bohr and Hauser-Feshbach models. (author)

Concentration and flux of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids for monitored tributaries of Lake Champlain, 1990-2012

Science.gov (United States)

Medalie, Laura

2014-01-01

Annual and daily concentrations and fluxes of total and dissolved phosphorus, total nitrogen, chloride, and total suspended solids were estimated for 18 monitored tributaries to Lake Champlain by using the Weighted Regressions on Time, Discharge, and Seasons regression model. Estimates were made for 21 or 23 years, depending on data availability, for the purpose of providing timely and accessible summary reports as stipulated in the 2010 update to the Lake Champlain “Opportunities for Action” management plan. Estimates of concentration and flux were provided for each tributary based on (1) observed daily discharges and (2) a flow-normalizing procedure, which removed the random fluctuations of climate-related variability. The flux bias statistic, an indicator of the ability of the Weighted Regressions on Time, Discharge, and Season regression models to provide accurate representations of flux, showed acceptable bias (less than ±10 percent) for 68 out of 72 models for total and dissolved phosphorus, total nitrogen, and chloride. Six out of 18 models for total suspended solids had moderate bias (between 10 and 30 percent), an expected result given the frequently nonlinear relation between total suspended solids and discharge. One model for total suspended solids with a very high bias was influenced by a single extreme value; however, removal of that value, although reducing the bias substantially, had little effect on annual fluxes.

Highly sensitive colour change system within slight differences in metal ion concentrations based on homo-binuclear complex formation equilibrium for visual threshold detection of trace metal ions

International Nuclear Information System (INIS)

Mizuguchi, Hitoshi; Atsumi, Hiroshi; Hashimoto, Keigo; Shimada, Yasuhiro; Kudo, Yuki; Endo, Masatoshi; Yokota, Fumihiko; Shida, Junichi; Yotsuyanagi, Takao

2004-01-01

A new technique of expressing slight differences in metal ion concentrations by clear difference in colour was established for visual threshold detection of trace metal ions. The proposed method is based on rapid change of the mole fraction of the homo-binuclear complex (M 2 L) about a ligand in a narrow range of the total metal ion concentration (M T ) in a small excess, in case the second metal ion is bound to the reagent molecule which can bind two metal ions. Theoretical simulations showed that the highly sensitive colour change within slight differences in metal ion concentrations would be realized under the following conditions: (i) both of the stepwise formation constants of complex species are sufficiently large; (ii) the stepwise formation constant of the 1:1 complex (ML) is larger than that of M 2 L; and (iii) the absorption spectrum of M 2 L is far apart from the other species in the visible region. Furthermore, the boundary of the colour region in M T would be readily controlled by the total ligand concentration (L T ). Based on this theory, the proposed model was verified with the 3,3'-bis[bis(carboxymethyl)amino]methyl derivatives of sulphonephthalein dyes such as xylenol orange (XO), methylthymol blue (MTB), and methylxylenol blue (MXB), which can bind two metal ions at both ends of a π-electron conjugated system. The above-mentioned model was proved with the iron(III)-XO system at pH 2. In addition, MTB and MXB were suitable reagents for the visual threshold detection of trivalent metal ions such as iron(III), aluminium(III), gallium(III) and indium(III) ion in slightly acidic media. The proposed method has been applied successfully as a screening test for aluminium(III) ion in river water sampled at the downstream area of an old mine

Report on the workshop on new directions in soft x-ray near-threshold phenomena

International Nuclear Information System (INIS)

Lindle, D.W.; Perera, R.C.C.

1988-07-01

The ''Workshop on New Directions in Soft X-Ray Near-Threshold Phenomena'' was held at the Asilomar Conference Center in Pacific Grove, CA on March 1--4, 1987. It was attended by 59 scientists from 8 countries, representing 27 institutions. Major funding for the meeting was donated by L-Division of the Lawrence Livermore National Laboratory, who hosted and organized two previous workshops on photoabsorption and scattering in the soft x-ray energy range. Additional funding was provided by the User's Group of the Advanced Light Source. The Workshop, as its name suggests, emphasized physical phenomena in atoms, molecules, and solids near inner-shell thresholds. Of particular interest were threshold ionization, post-collisional interaction, resonant photoemission and fluorescence, and multi-electron effects such as shake-up and shake-off. In these areas and others, special consideration was given to presenting recent discoveries and potential ''new directions'' for future work

Particles near threshold

International Nuclear Information System (INIS)

Bhattacharya, T.; Willenbrock, S.

1993-01-01

We propose returning to the definition of the width of a particle in terms of the pole in the particle's propagator. Away from thresholds, this definition of width is equivalent to the standard perturbative definition, up to next-to-leading order; however, near a threshold, the two definitions differ significantly. The width as defined by the pole position provides more information in the threshold region than the standard perturbative definition and, in contrast with the perturbative definition, does not vanish when a two-particle s-wave threshold is approached from below

Cementification for radioactive waste including high-concentration sodium sulfate and high-concentration radioactive nuclide

International Nuclear Information System (INIS)

Miyamoto, Shinya; Sato, Tatsuaki; Sasoh, Michitaka; Sakurai, Jiro; Takada, Takao

2005-01-01

For the cementification of radioactive waste that has large concentrations of sodium sulfate and radioactive nuclide, a way of fixation for sulfate ion was studied comprising the pH control of water in contact with the cement solid, and the removal of the excess water from the cement matrix to prevent hydrogen gas generation with radiolysis. It was confirmed that the sulfate ion concentration in the contacted water with the cement solid is decreased with the formation of ettringite or barium sulfate before solidification, the pH value of the pore water in the cement solid can control less than 12.5 by the application of zeolite and a low-alkali cement such as alumina cement or fly ash mixed cement, and removal of the excess water from the cement matrix by heating is possible with aggregate addition. Consequently, radioactive waste including high-concentration sodium sulfate and high-concentration radioactive nuclide can be solidified with cementitious materials. (author)

Multiple imputation for multivariate data with missing and below-threshold measurements: time-series concentrations of pollutants in the Arctic.

Science.gov (United States)

Hopke, P K; Liu, C; Rubin, D B

2001-03-01

Many chemical and environmental data sets are complicated by the existence of fully missing values or censored values known to lie below detection thresholds. For example, week-long samples of airborne particulate matter were obtained at Alert, NWT, Canada, between 1980 and 1991, where some of the concentrations of 24 particulate constituents were coarsened in the sense of being either fully missing or below detection limits. To facilitate scientific analysis, it is appealing to create complete data by filling in missing values so that standard complete-data methods can be applied. We briefly review commonly used strategies for handling missing values and focus on the multiple-imputation approach, which generally leads to valid inferences when faced with missing data. Three statistical models are developed for multiply imputing the missing values of airborne particulate matter. We expect that these models are useful for creating multiple imputations in a variety of incomplete multivariate time series data sets.

Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose

Directory of Open Access Journals (Sweden)

Felby Claus

2009-06-01

Full Text Available Abstract Background Working at high solids (substrate concentrations is advantageous in enzymatic conversion of lignocellulosic biomass as it increases product concentrations and plant productivity while lowering energy and water input. However, for a number of lignocellulosic substrates it has been shown that at increasing substrate concentration, the corresponding yield decreases in a fashion which can not be explained by current models and knowledge of enzyme-substrate interactions. This decrease in yield is undesirable as it offsets the advantages of working at high solids levels. The cause of the 'solids effect' has so far remained unknown. Results The decreasing conversion at increasing solids concentrations was found to be a generic or intrinsic effect, describing a linear correlation from 5 to 30% initial total solids content (w/w. Insufficient mixing has previously been shown not to be involved in the effect. Hydrolysis experiments with filter paper showed that neither lignin content nor hemicellulose-derived inhibitors appear to be responsible for the decrease in yields. Product inhibition by glucose and in particular cellobiose (and ethanol in simultaneous saccharification and fermentation at the increased concentrations at high solids loading plays a role but could not completely account for the decreasing conversion. Adsorption of cellulases was found to decrease at increasing solids concentrations. There was a strong correlation between the decreasing adsorption and conversion, indicating that the inhibition of cellulase adsorption to cellulose is causing the decrease in yield. Conclusion Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing yields at increasing substrate concentrations in the enzymatic decomposition of cellulosic biomass. In order to facilitate high conversions at high solids concentrations, understanding of the mechanisms involved in high-solids product inhibition

Solids Accumulation Scouting Studies

Energy Technology Data Exchange (ETDEWEB)

Duignan, M. R.; Steeper, T. J.; Steimke, J. L.

2012-09-26

The objective of Solids Accumulation activities was to perform scaled testing to understand the behavior of remaining solids in a Double Shell Tank (DST), specifically AW-105, at Hanford during multiple fill, mix, and transfer operations. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles containing plutonium could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste staging tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids: Gibbsite, Zirconia, Sand, and Stainless Steel, with stainless steel particles representing the heavier particles, e.g., plutonium, and supernatant were charged to the test tank and rotating liquid jets were used to mix most of the solids while the simulant was pumped out. Subsequently, the volume and shape of the mounds of residual solids and the spatial concentration profiles for the surrogate for heavier particles were measured. Several techniques were developed and equipment designed to accomplish the measurements needed and they included: 1. Magnetic particle separator to remove simulant stainless steel solids. A device was designed and built to capture these solids, which represent the heavier solids during a waste transfer from a staging tank. 2. Photographic equipment to determine the volume of the solids mounds. The mounds were photographed as they were exposed at different tank waste levels to develop a composite of topographical areas. 3. Laser rangefinders to determine the volume of

Filterability and Sludge Concentration in Membrane Bioreactors

NARCIS (Netherlands)

Lousada-Ferreira, M.

2011-01-01

The Thesis entitled “Filterability and Sludge Concentration in Membrane Bioreactors” aims at explaining the relation between Mixed Liquid Suspended Solids (MLSS) concentration, the amount of solids in the wastewater being treated, also designated as sludge, and filterability, being the ability of

Occupational hygiene in terms of volatile organic compounds (VOCs) and bioaerosols at two solid waste management plants in Finland

International Nuclear Information System (INIS)

Lehtinen, Jenni; Tolvanen, Outi; Nivukoski, Ulla; Veijanen, Anja; Hänninen, Kari

2013-01-01

Highlights: ► Odorous VOCs: acetic acid, 2,3-butanedione, ethyl acetate, alpha-pinene and limonene. ► VOC concentrations did not exceed occupational exposure limit concentrations. ► 2,3-Butanedione as the health effecting compound is discussed. ► Endotoxin concentrations may cause health problems in waste treatment. - Abstract: Factors affecting occupational hygiene were measured at the solid waste transferring plant at Hyvinkää and at the optic separation plant in Hämeenlinna. Measurements consisted of volatile organic compounds (VOCs) and bioaerosols including microbes, dust and endotoxins. The most abundant compounds in both of the plants were aliphatic and aromatic hydrocarbons, esters of carboxylic acids, ketones and terpenes. In terms of odour generation, the most important emissions were acetic acid, 2,3-butanedione, ethyl acetate, alpha-pinene and limonene due to their low threshold odour concentrations. At the optic waste separation plant, limonene occurred at the highest concentration of all single compounds of identified VOCs. The concentration of any single volatile organic compound did not exceed the occupational exposure limit (OEL) concentration. However, 2,3-butanedione as a health risk compound is discussed based on recent scientific findings linking it to lung disease. Microbe and dust concentrations were low at the waste transferring plant. Only endotoxin concentrations may cause health problems; the average concentration inside the plant was 425 EU/m 3 which clearly exceeded the threshold value of 90 EU/m 3 . In the wheel loader cabin the endotoxin concentrations were below 1 EU/m 3 . High microbial and endotoxin concentrations were measured in the processing hall at the optic waste separation plant. The average concentration of endotoxins was found to be 10,980 EU/m 3 , a concentration which may cause health risks. Concentrations of viable fungi were quite high in few measurements in the control room. The most problematic factor was

Occupational hygiene in terms of volatile organic compounds (VOCs) and bioaerosols at two solid waste management plants in Finland

Energy Technology Data Exchange (ETDEWEB)

Lehtinen, Jenni, E-mail: jenni.k.lehtinen@jyu.fi [University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, 40014 Jyväskylä (Finland); Tolvanen, Outi; Nivukoski, Ulla; Veijanen, Anja; Hänninen, Kari [University of Jyväskylä, Department of Biological and Environmental Science, P.O. Box 35, 40014 Jyväskylä (Finland)

2013-04-15

Highlights: ► Odorous VOCs: acetic acid, 2,3-butanedione, ethyl acetate, alpha-pinene and limonene. ► VOC concentrations did not exceed occupational exposure limit concentrations. ► 2,3-Butanedione as the health effecting compound is discussed. ► Endotoxin concentrations may cause health problems in waste treatment. - Abstract: Factors affecting occupational hygiene were measured at the solid waste transferring plant at Hyvinkää and at the optic separation plant in Hämeenlinna. Measurements consisted of volatile organic compounds (VOCs) and bioaerosols including microbes, dust and endotoxins. The most abundant compounds in both of the plants were aliphatic and aromatic hydrocarbons, esters of carboxylic acids, ketones and terpenes. In terms of odour generation, the most important emissions were acetic acid, 2,3-butanedione, ethyl acetate, alpha-pinene and limonene due to their low threshold odour concentrations. At the optic waste separation plant, limonene occurred at the highest concentration of all single compounds of identified VOCs. The concentration of any single volatile organic compound did not exceed the occupational exposure limit (OEL) concentration. However, 2,3-butanedione as a health risk compound is discussed based on recent scientific findings linking it to lung disease. Microbe and dust concentrations were low at the waste transferring plant. Only endotoxin concentrations may cause health problems; the average concentration inside the plant was 425 EU/m{sup 3} which clearly exceeded the threshold value of 90 EU/m{sup 3}. In the wheel loader cabin the endotoxin concentrations were below 1 EU/m{sup 3}. High microbial and endotoxin concentrations were measured in the processing hall at the optic waste separation plant. The average concentration of endotoxins was found to be 10,980 EU/m{sup 3}, a concentration which may cause health risks. Concentrations of viable fungi were quite high in few measurements in the control room. The most

Tribo-electric charging of dielectric solids of identical composition

Science.gov (United States)

Angus, John C.; Greber, Isaac

2018-05-01

Despite its long history and importance in many areas of science and technology, there is no agreement on the mechanisms responsible for tribo-electric charging, including especially the tribo-charging of chemically identical dielectric solids. Modeling of the excitation, diffusional transport, and de-excitation of electrons from hot spots shows that a difference in local surface roughness of otherwise identical solid dielectric objects leads to different transient excited electron concentrations during tribo-processes. The model predicts that excited electron concentrations are lower and concentration gradients higher in solids with rougher rather than smoother surfaces. Consequently, during contact, the flux of charge carriers (electrons or holes) from hot spots will be greater into the rougher solid than into the smoother solid. These predictions are in agreement with current and historical observations of tribo-electric charge transfer between solids of the same composition. This effect can take place in parallel with other processes and may also play a role in the charging of solids of different composition.

Concentrations: Recent Developments in Italy

Directory of Open Access Journals (Sweden)

Claudio Tesauro

2015-10-01

Full Text Available Recent Italian developments in antitrust concentrations was the topic I was assigned to address at the conference held on 23 April to celebrate the first anniversary of the Italian Antitrust Review. What is immediately clear is that far fewer concentrations have been notified over the last few years. This is probably due to the economic crisis, which caused a reduction in corporate transactions; but also the changes to the turnover thresholds for notification seem to have had a significant impact. Consequently, an interesting debate is underway regarding the need for further changes the threshold system. Moreover, the drastic market developments and the subsequent increased number of decisions to revise remedies should also be further examined. These two issues are the subject of this paper.

Development of Thresholds and Exceedance Probabilities for Influent Water Quality to Meet Drinking Water Regulations

Science.gov (United States)

Reeves, K. L.; Samson, C.; Summers, R. S.; Balaji, R.

2017-12-01

Drinking water treatment utilities (DWTU) are tasked with the challenge of meeting disinfection and disinfection byproduct (DBP) regulations to provide safe, reliable drinking water under changing climate and land surface characteristics. DBPs form in drinking water when disinfectants, commonly chlorine, react with organic matter as measured by total organic carbon (TOC), and physical removal of pathogen microorganisms are achieved by filtration and monitored by turbidity removal. Turbidity and TOC in influent waters to DWTUs are expected to increase due to variable climate and more frequent fires and droughts. Traditional methods for forecasting turbidity and TOC require catchment specific data (i.e. streamflow) and have difficulties predicting them under non-stationary climate. A modelling framework was developed to assist DWTUs with assessing their risk for future compliance with disinfection and DBP regulations under changing climate. A local polynomial method was developed to predict surface water TOC using climate data collected from NOAA, Normalized Difference Vegetation Index (NDVI) data from the IRI Data Library, and historical TOC data from three DWTUs in diverse geographic locations. Characteristics from the DWTUs were used in the EPA Water Treatment Plant model to determine thresholds for influent TOC that resulted in DBP concentrations within compliance. Lastly, extreme value theory was used to predict probabilities of threshold exceedances under the current climate. Results from the utilities were used to produce a generalized TOC threshold approach that only requires water temperature and bromide concentration. The threshold exceedance model will be used to estimate probabilities of exceedances under projected climate scenarios. Initial results show that TOC can be forecasted using widely available data via statistical methods, where temperature, precipitation, Palmer Drought Severity Index, and NDVI with various lags were shown to be important

Radiometers for radon concentration in air

International Nuclear Information System (INIS)

Bartak, J.; Machaj, B.; Pienkos, J.P.

2002-01-01

Constant grow of science and technology stimulates development of new improved measuring tools. New measuring demand arise also in radon concentration measurements. Varying rock stress and rock cracks influencing radon emanation encouraged research aimed at use of this phenomenon to predict crumps of mine formation among others based on variation of radon emanation. A measuring set was developed in the Institute of Nuclear Chemistry and Technology enabling long term monitoring of radon concentration in mine bore-hole. The set consists probe and probe controller. Detection threshold of the probe is 230 Bq/m 3 . The set can operate in the environment with methane explosion hazard. A radiometer employing Lucas cell as radiation detector for radon concentration in air was also developed its detection threshold is approx. 10 Bq/m 3 . Replaceable Lucas cell of the radiometer allows for measurement of high as well as low radon concentration in short time interval. (author)

Urine Concentration and Pyuria for Identifying UTI in Infants.

Science.gov (United States)

Chaudhari, Pradip P; Monuteaux, Michael C; Bachur, Richard G

2016-11-01

Varying urine white blood cell (WBC) thresholds have been recommended for the presumptive diagnosis of urinary tract infection (UTI) among young infants. These thresholds have not been studied with newer automated urinalysis systems that analyze uncentrifuged urine that might be influenced by urine concentration. Our objective was to determine the optimal urine WBC threshold for UTI in young infants by using an automated urinalysis system, stratified by urine concentration. Retrospective cross-sectional study of infants aged UTI in the emergency department with paired urinalysis and urine culture. UTI was defined as ≥50 000 colony-forming units/mL from catheterized specimens. Test characteristics were calculated across a range of WBC and leukocyte esterase (LE) cut-points, dichotomized into specific gravity groups (dilute UTI prevalence was 7.8%. Optimal WBC cut-points were 3 WBC/high-power field (HPF) in dilute urine (likelihood ratio positive [LR+] 9.9, likelihood ratio negative [LR‒] 0.15) and 6 WBC/HPF (LR+ 10.1, LR‒ 0.17) in concentrated urine. For dipstick analysis, positive LE has excellent test characteristics regardless of urine concentration (LR+ 22.1, LR‒ 0.12 in dilute urine; LR+ 31.6, LR‒ 0.22 in concentrated urine). Urine concentration should be incorporated into the interpretation of automated microscopic urinalysis in young infants. Pyuria thresholds of 3 WBC/HPF in dilute urine and 6 WBC/HPF in concentrated urine are recommended for the presumptive diagnosis of UTI. Without correction of specific gravity, positive LE by automated dipstick is a reliably strong indicator of UTI. Copyright © 2016 by the American Academy of Pediatrics.

A Bayesian changepoint-threshold model to examine the effect of TMDL implementation on the flow-nitrogen concentration relationship in the Neuse River basin.

Science.gov (United States)

Alameddine, Ibrahim; Qian, Song S; Reckhow, Kenneth H

2011-01-01

In-stream nutrient concentrations are well known to exhibit a strong relationship with river flow. The use of flow measurements to predict nutrient concentrations and subsequently nutrient loads is common in water quality modeling. Nevertheless, most adopted models assume that the relationship between flow and concentration is fixed across time as well as across different flow regimes. In this study, we developed a Bayesian changepoint-threshold model that relaxes these constraints and allows for the identification and quantification of any changes in the underlying flow-concentration relationship across time. The results from our study support the occurrence of a changepoint in time around the year 1999, which coincided with the period of implementing nitrogen control measures as part of the TMDL program developed for the Neuse Estuary in North Carolina. The occurrence of the changepoint challenges the underlying assumption of temporal invariance in the flow-concentrations relationship. The model results also point towards a transition in the river nitrogen delivery system from a point source dominated loading system towards a more complicated nonlinear system, where non-point source nutrient delivery plays a major role. Moreover, we use the developed model to assess the effectiveness of the nitrogen reduction measures in achieving a 30% drop in loading. The results indicate that while there is a strong evidence of a load reduction, there still remains a high level of uncertainty associated with the mean nitrogen load reduction. We show that the level of uncertainty around the estimated load reduction is not random but is flow related. Copyright © 2010 Elsevier Ltd. All rights reserved.

Rheology of concentrated biomass

Science.gov (United States)

J.R. Samaniuk; J. Wang; T.W. Root; C.T. Scott; D.J. Klingenberg

2011-01-01

Economic processing of lignocellulosic biomass requires handling the biomass at high solids concentration. This creates challenges because concentrated biomass behaves as a Bingham-like material with large yield stresses. Here we employ torque rheometry to measure the rheological properties of concentrated lignocellulosic biomass (corn stover). Yield stresses obtained...

Laser generation of nanostructures on the surface and in the bulk of solids

International Nuclear Information System (INIS)

Bityurin, N M

2010-01-01

This paper considers nanostructuring of solid surfaces by nano-optical techniques, primarily by laser particle nanolithography. Threshold processes are examined that can be used for laser structuring of solid surfaces, with particular attention to laser swelling of materials. Fundamental spatial resolution issues in three-dimensional (3D) laser nanostructuring are analysed with application to laser nanopolymerisation and 3D optical information recording. The formation of nanostructures in the bulk of solids due to their structural instability under irradiation is exemplified by photoinduced formation of nanocomposites. (photonics and nanotechnology)

Biohydrogen production from household solid waste (HSW) at extreme-thermophilic temperature (70 degrees C) - Influence of pH and acetate concentration

DEFF Research Database (Denmark)

Liu, Dawei; Min, Booki; Angelidaki, Irini

2008-01-01

Hydrogen production from household solid waste (HSW) was performed via dark fermentation by using an extreme-thermophilic mixed culture, and the effect of pH and acetate on the biohydrogen production was investigated. The highest hydrogen production yield was 257 +/- 25 mL/gVS(added) at the optimum...... pH of 7.0. Acetate was proved to be inhibiting the dark fermentation process at neutral pH, which indicates that the inhibition was caused by total acetate concentration not by undissociated acetate. Initial inhibition was detected at acetate concentration of 50 mM, while the hydrogen fermentation...

All solid-state SBS phase conjugate mirror

Science.gov (United States)

Dane, C.B.; Hackel, L.A.

1999-03-09

A stimulated Brillouin scattering (SBS) phase conjugate laser mirror uses a solid-state nonlinear gain medium instead of the conventional liquid or high pressure gas medium. The concept has been effectively demonstrated using common optical-grade fused silica. An energy threshold of 2.5 mJ and a slope efficiency of over 90% were achieved, resulting in an overall energy reflectivity of >80% for 15 ns, 1 um laser pulses. The use of solid-state materials is enabled by a multi-pass resonant architecture which suppresses transient fluctuations that would otherwise result in damage to the SBS medium. This all solid state phase conjugator is safer, more reliable, and more easily manufactured than prior art designs. It allows nonlinear wavefront correction to be implemented in industrial and defense laser systems whose operating environments would preclude the introduction of potentially hazardous liquids or high pressure gases. 8 figs.

Lower versus higher hemoglobin threshold for transfusion in septic shock.

Science.gov (United States)

Holst, Lars B; Haase, Nicolai; Wetterslev, Jørn; Wernerman, Jan; Guttormsen, Anne B; Karlsson, Sari; Johansson, Pär I; Aneman, Anders; Vang, Marianne L; Winding, Robert; Nebrich, Lars; Nibro, Helle L; Rasmussen, Bodil S; Lauridsen, Johnny R M; Nielsen, Jane S; Oldner, Anders; Pettilä, Ville; Cronhjort, Maria B; Andersen, Lasse H; Pedersen, Ulf G; Reiter, Nanna; Wiis, Jørgen; White, Jonathan O; Russell, Lene; Thornberg, Klaus J; Hjortrup, Peter B; Müller, Rasmus G; Møller, Morten H; Steensen, Morten; Tjäder, Inga; Kilsand, Kristina; Odeberg-Wernerman, Suzanne; Sjøbø, Brit; Bundgaard, Helle; Thyø, Maria A; Lodahl, David; Mærkedahl, Rikke; Albeck, Carsten; Illum, Dorte; Kruse, Mary; Winkel, Per; Perner, Anders

2014-10-09

Blood transfusions are frequently given to patients with septic shock. However, the benefits and harms of different hemoglobin thresholds for transfusion have not been established. In this multicenter, parallel-group trial, we randomly assigned patients in the intensive care unit (ICU) who had septic shock and a hemoglobin concentration of 9 g per deciliter or less to receive 1 unit of leukoreduced red cells when the hemoglobin level was 7 g per deciliter or less (lower threshold) or when the level was 9 g per deciliter or less (higher threshold) during the ICU stay. The primary outcome measure was death by 90 days after randomization. We analyzed data from 998 of 1005 patients (99.3%) who underwent randomization. The two intervention groups had similar baseline characteristics. In the ICU, the lower-threshold group received a median of 1 unit of blood (interquartile range, 0 to 3) and the higher-threshold group received a median of 4 units (interquartile range, 2 to 7). At 90 days after randomization, 216 of 502 patients (43.0%) assigned to the lower-threshold group, as compared with 223 of 496 (45.0%) assigned to the higher-threshold group, had died (relative risk, 0.94; 95% confidence interval, 0.78 to 1.09; P=0.44). The results were similar in analyses adjusted for risk factors at baseline and in analyses of the per-protocol populations. The numbers of patients who had ischemic events, who had severe adverse reactions, and who required life support were similar in the two intervention groups. Among patients with septic shock, mortality at 90 days and rates of ischemic events and use of life support were similar among those assigned to blood transfusion at a higher hemoglobin threshold and those assigned to blood transfusion at a lower threshold; the latter group received fewer transfusions. (Funded by the Danish Strategic Research Council and others; TRISS ClinicalTrials.gov number, NCT01485315.).

Density of phonon-fracton states of disordered solids in the vicinity of percolation phase transitions

International Nuclear Information System (INIS)

Korzhenevskii, A.L.; Luzhkov, A.A.

1991-01-01

The development of a theory of phase transitions in disordered materials is still one of the central problems in solid-state physics. The model of a percolation phase transition plays the same role among the models put forward to account for phase transitions in disordered media as does the Ising model for second-order phase transitions in ideal crystals. In addition to the clear picture of the processes occurring in the course of a percolation phase transition, a scaling theory has been developed and various techniques have been used to calculate the critical exponents describing the thermodynamics of a medium in the vicinity of the percolation threshold. The authors adopt a field-theoretic approach in a study of acoustic properties of disordered solids undergoing percolation phase transitions characterized by h ∼ 1. Among these transitions they concentrate on the case with the simplest type of striction interaction when the solution of a stochastic vector differential equation of motion describing the behavior of an elastic medium in the critical region can be reduced to a scalar equation. The results of their calculations by the field renormalization group method confirmed the existence of the scaling relationships between the critical exponents and also the conclusion on the nature of short- and long-wavelength vibrations near the percolation threshold, which follow from phenomenological considerations of the scaling theory. The values of the upper critical dimensionality and of the critical exponents of the problem are shown to differ from the values applicable to percolation phase transitions characterized by h much-lt 1

The effect of ultrasonic pretreatment on biogas generation yield from organic fraction of municipal solid waste under medium solids concentration circumstance

International Nuclear Information System (INIS)

Rasapoor, Mazdak; Ajabshirchi, Yahya; Adl, Mehrdad; Abdi, Reza; Gharibi, Arash

2016-01-01

Highlights: • Ultrasonic pretreatment improved biogas yields at lower TS content samples. • Time of ultrasonication was significantly effective on maximum biogas yields. • Ultrasonic pretreatment can cause the release of TVFA content before digestion. • Specific energy between 5000 kJ/kg TS and 10,000 kJ/kg TS improved biogas yields. - Abstract: Hydrolysis is the most rate limiting step in almost all anaerobic digestion systems. To tackle long time duration, ultrasonic pretreatment proved that it can effectively improve biogas yield efficiency by effecting on soluble particles. In this study, the effect of three different ultrasonic power densities (0.2 W/mL, 0.4 W/mL and 0.6 W/mL) at three different times (10 min, 20 min and 30 min) on biogas yield of organic fraction of municipal solid waste (OFMSW) at three different total solid content (6%, 8% and 10%) were analyzed. Results showed significant (p < 0.01) effect of both sonication density and time of sonication on biogas final yield and biogas yield after 72 h digestion with the 6% TS content. Parameters like specific energy input and total volatile fatty acid (TVFA) content were also evaluated to find the best sonication treatments for OFMSW. For lower TS contents (6% and 8%), sonication treatment significantly (p < 0.01) increased TVFA concentration before digesting. It is also proved that specific energy input between 5000 kJ/kg TS and 10,000 kJ/kg TS can effectively increase the biogas yields, especially for 6% TS content, and caused maximum biogas yield produced after 72 h of digestion.

Determination and validation of soil thresholds for cadmium based on food quality standard and health risk assessment.

Science.gov (United States)

Ding, Changfeng; Ma, Yibing; Li, Xiaogang; Zhang, Taolin; Wang, Xingxiang

2018-04-01

Cadmium (Cd) is an environmental toxicant with high rates of soil-plant transfer. It is essential to establish an accurate soil threshold for the implementation of soil management practices. This study takes root vegetable as an example to derive soil thresholds for Cd based on the food quality standard as well as health risk assessment using species sensitivity distribution (SSD). A soil type-specific bioconcentration factor (BCF, ratio of Cd concentration in plant to that in soil) generated from soil with a proper Cd concentration gradient was calculated and applied in the derivation of soil thresholds instead of a generic BCF value to minimize the uncertainty. The sensitivity variations of twelve root vegetable cultivars for accumulating soil Cd and the empirical soil-plant transfer model were investigated and developed in greenhouse experiments. After normalization, the hazardous concentrations from the fifth percentile of the distribution based on added Cd (HC5 add ) were calculated from the SSD curves fitted by Burr Type III distribution. The derived soil thresholds were presented as continuous or scenario criteria depending on the combination of soil pH and organic carbon content. The soil thresholds based on food quality standard were on average 0.7-fold of those based on health risk assessment, and were further validated to be reliable using independent data from field survey and published articles. The results suggested that deriving soil thresholds for Cd using SSD method is robust and also applicable to other crops as well as other trace elements that have the potential to cause health risk issues. Copyright © 2017 Elsevier B.V. All rights reserved.

Threshold Signature Schemes Application

Directory of Open Access Journals (Sweden)

Anastasiya Victorovna Beresneva

2015-10-01

Full Text Available This work is devoted to an investigation of threshold signature schemes. The systematization of the threshold signature schemes was done, cryptographic constructions based on interpolation Lagrange polynomial, elliptic curves and bilinear pairings were examined. Different methods of generation and verification of threshold signatures were explored, the availability of practical usage of threshold schemes in mobile agents, Internet banking and e-currency was shown. The topics of further investigation were given and it could reduce a level of counterfeit electronic documents signed by a group of users.

Thresholds in radiobiology

International Nuclear Information System (INIS)

Katz, R.; Hofmann, W.

1982-01-01

Interpretations of biological radiation effects frequently use the word 'threshold'. The meaning of this word is explored together with its relationship to the fundamental character of radiation effects and to the question of perception. It is emphasised that although the existence of either a dose or an LET threshold can never be settled by experimental radiobiological investigations, it may be argued on fundamental statistical grounds that for all statistical processes, and especially where the number of observed events is small, the concept of a threshold is logically invalid. (U.K.)

Determination of trace level thorium and uranium in high purity gadolinium sulfate using ICP-MS with solid-phase chromatographic extraction resins

Science.gov (United States)

Ito, S.; Takaku, Y.; Ikeda, M.; Kishimoto, Y.

2018-01-01

The Super Kamiokand-Gadolinium (SK-Gd) project is the upgrade of the Super-Kamiokande (SK) detector in order to discover Supernova Relic Neutrinos (SRNs) by loading 0.2% of Gd2(SO4)3 into a 50 kton of the SK water tank. In order to continue solar neutrino measurement with low energy threshold at ˜3.5 MeV, main radioactive contamination, U and Th in Gd2(SO4)3, should be purified before loading. We developed solid-phase extraction technique to measure low concentration of U and Th in Gd2(SO4)3 by ICP-MS. The extraction technique and current status will be presented.

Preferential Concentration Of Solid Particles In Turbulent Horizontal Circular Pipe Flow

Science.gov (United States)

Kim, Jaehee; Yang, Kyung-Soo

2017-11-01

In particle-laden turbulent pipe flow, turbophoresis can lead to a preferential concentration of particles near the wall. To investigate this phenomenon, one-way coupled Direct Numerical Simulation (DNS) has been performed. Fully-developed turbulent pipe flow of the carrier fluid (air) is at Reτ = 200 based on the pipe radius and the mean friction velocity, whereas the Stokes numbers of the particles (solid) are St+ = 0.1 , 1 , 10 based on the mean friction velocity and the kinematic viscosity of the fluid. The computational domain for particle simulation is extended along the axial direction by duplicating the domain of the fluid simulation. By doing so, particle statistics in the spatially developing region as well as in the fully-developed region can be obtained. Accumulation of particles has been noticed at St+ = 1 and 10 mostly in the viscous sublayer, more intensive in the latter case. Compared with other authors' previous results, our results suggest that drag force on the particles should be computed by using an empirical correlation and a higher-order interpolation scheme even in a low-Re regime in order to improve the accuracy of particle simulation. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2015R1A2A2A01002981).

Electronic excitations in fast ion-solid collisions

International Nuclear Information System (INIS)

Burgdoerfer, J.

1990-01-01

We review recent developments in the study of electronic excitation of projectiles in fast ion-solid collisions. Our focus will be primarily on theory but experimental advances will also be discussed. Topics include the evidence for velocity-dependent thresholds for the existence of bound states, wake-field effects on excited states, the electronic excitation of channeled projectiles, transport phenomena, and the interaction of highly charged ions with surfaces. 44 refs., 14 figs

Cladding for transverse-pumped solid-state laser

Science.gov (United States)

Byer, Robert L. (Inventor); Fan, Tso Y. (Inventor)

1989-01-01

In a transverse pumped, solid state laser, a nonabsorptive cladding surrounds a gain medium. A single tranverse mode, namely the Transverse Electromagnetic (TEM) sub 00 mode, is provided. The TEM sub 00 model has a cross sectional diameter greater than a transverse dimension of the gain medium but less than a transverse dimension of the cladding. The required size of the gain medium is minimized while a threshold for laser output is lowered.

Shifts in the relationship between motor unit recruitment thresholds versus derecruitment thresholds during fatigue.

Science.gov (United States)

Stock, Matt S; Mota, Jacob A

2017-12-01

Muscle fatigue is associated with diminished twitch force amplitude. We examined changes in the motor unit recruitment versus derecruitment threshold relationship during fatigue. Nine men (mean age = 26 years) performed repeated isometric contractions at 50% maximal voluntary contraction (MVC) knee extensor force until exhaustion. Surface electromyographic signals were detected from the vastus lateralis, and were decomposed into their constituent motor unit action potential trains. Motor unit recruitment and derecruitment thresholds and firing rates at recruitment and derecruitment were evaluated at the beginning, middle, and end of the protocol. On average, 15 motor units were studied per contraction. For the initial contraction, three subjects showed greater recruitment thresholds than derecruitment thresholds for all motor units. Five subjects showed greater recruitment thresholds than derecruitment thresholds for only low-threshold motor units at the beginning, with a mean cross-over of 31.6% MVC. As the muscle fatigued, many motor units were derecruited at progressively higher forces. In turn, decreased slopes and increased y-intercepts were observed. These shifts were complemented by increased firing rates at derecruitment relative to recruitment. As the vastus lateralis fatigued, the central nervous system's compensatory adjustments resulted in a shift of the regression line of the recruitment versus derecruitment threshold relationship. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

Vertical hydraulic transport of particulate solids

International Nuclear Information System (INIS)

Restini, C.V.; Massarani, G.

1977-01-01

The problem of particulate solid vertical transport is formulated using the conservation equations of Continuum Mechanics. It is shown that the constitutive equation for solid-fluid interaction term in the equations of motion may be determined by rather simple experiments of homogeneous fluidization. The predicted fluid pressure drop and solid concentration are in satisfacting agreement with past experiments and with data obtained in this work. (Author) [pt

Threshold factorization redux

Science.gov (United States)

Chay, Junegone; Kim, Chul

2018-05-01

We reanalyze the factorization theorems for the Drell-Yan process and for deep inelastic scattering near threshold, as constructed in the framework of the soft-collinear effective theory (SCET), from a new, consistent perspective. In order to formulate the factorization near threshold in SCET, we should include an additional degree of freedom with small energy, collinear to the beam direction. The corresponding collinear-soft mode is included to describe the parton distribution function (PDF) near threshold. The soft function is modified by subtracting the contribution of the collinear-soft modes in order to avoid double counting on the overlap region. As a result, the proper soft function becomes infrared finite, and all the factorized parts are free of rapidity divergence. Furthermore, the separation of the relevant scales in each factorized part becomes manifest. We apply the same idea to the dihadron production in e+e- annihilation near threshold, and show that the resultant soft function is also free of infrared and rapidity divergences.

Near threshold two meson production in hardonic fusion reactions

International Nuclear Information System (INIS)

Jahn, R.

1991-01-01

An approved and funded exclusive COSY experiment is presented, which focuses on near threshold two meson production via the reactions p+d→ 3 He + π + π - and p+d→ 3 He+K + K-. It takes advantage of the high quality of the cooled external COSY beam and the existing spectrometer BIG KARL. The setup consists of a vertex wall and a scintillator cylinder and endcap covering a 4π solid angle. The large efficiency and high resolution of this detection method will yield precision data on the low energy (T 0 (975). Existing inclusive data as well as first results of a very recent 'semi-exclusive' experiment performed at SATURNE will be also be presented

Comparison between intensity- duration thresholds and cumulative rainfall thresholds for the forecasting of landslide

Science.gov (United States)

Lagomarsino, Daniela; Rosi, Ascanio; Rossi, Guglielmo; Segoni, Samuele; Catani, Filippo

2014-05-01

This work makes a quantitative comparison between the results of landslide forecasting obtained using two different rainfall threshold models, one using intensity-duration thresholds and the other based on cumulative rainfall thresholds in an area of northern Tuscany of 116 km2. The first methodology identifies rainfall intensity-duration thresholds by means a software called MaCumBA (Massive CUMulative Brisk Analyzer) that analyzes rain-gauge records, extracts the intensities (I) and durations (D) of the rainstorms associated with the initiation of landslides, plots these values on a diagram, and identifies thresholds that define the lower bounds of the I-D values. A back analysis using data from past events can be used to identify the threshold conditions associated with the least amount of false alarms. The second method (SIGMA) is based on the hypothesis that anomalous or extreme values of rainfall are responsible for landslide triggering: the statistical distribution of the rainfall series is analyzed, and multiples of the standard deviation (σ) are used as thresholds to discriminate between ordinary and extraordinary rainfall events. The name of the model, SIGMA, reflects the central role of the standard deviations in the proposed methodology. The definition of intensity-duration rainfall thresholds requires the combined use of rainfall measurements and an inventory of dated landslides, whereas SIGMA model can be implemented using only rainfall data. These two methodologies were applied in an area of 116 km2 where a database of 1200 landslides was available for the period 2000-2012. The results obtained are compared and discussed. Although several examples of visual comparisons between different intensity-duration rainfall thresholds are reported in the international literature, a quantitative comparison between thresholds obtained in the same area using different techniques and approaches is a relatively undebated research topic.

Total Protein of Whole Saliva as a Biomarker of Anaerobic Threshold

Science.gov (United States)

Bortolini, Miguel Junior Sordi; De Agostini, Guilherme Gularte; Reis, Ismair Teodoro; Lamounier, Romeu Paulo Martins Silva; Blumberg, Jeffrey B.; Espindola, Foued Salmen

2009-01-01

Saliva provides a convenient and noninvasive matrix for assessing specific physiological parameters, including some biomarkers of exercise. We investigated whether the total protein concentration of whole saliva (TPWS) would reflect the anaerobic threshold during an incremental exercise test. After a warm-up period, 13 nonsmoking men performed a…

In-vitro singlet oxygen threshold dose at PDT with Radachlorin photosensitizer

Science.gov (United States)

Klimenko, V. V.; Shmakov, S. V.; Kaydanov, N. E.; Knyazev, N. A.; Kazakov, N. V.; Rusanov, A. A.; Bogdanov, A. A.; Dubina, M. V.

2017-07-01

In this present study we investigate the Radachlorin photosensitizer accumulation in K562 cells and Hela cells and determined the cell viability after PDT. Using the macroscopic singlet oxygen modeling and cellular photosensitizer concentration the singlet oxygen threshold doses for K562 cells and Hela cells were calculated.

Detection thresholds of macaque otolith afferents.

Science.gov (United States)

Yu, Xiong-Jie; Dickman, J David; Angelaki, Dora E

2012-06-13

The vestibular system is our sixth sense and is important for spatial perception functions, yet the sensory detection and discrimination properties of vestibular neurons remain relatively unexplored. Here we have used signal detection theory to measure detection thresholds of otolith afferents using 1 Hz linear accelerations delivered along three cardinal axes. Direction detection thresholds were measured by comparing mean firing rates centered on response peak and trough (full-cycle thresholds) or by comparing peak/trough firing rates with spontaneous activity (half-cycle thresholds). Thresholds were similar for utricular and saccular afferents, as well as for lateral, fore/aft, and vertical motion directions. When computed along the preferred direction, full-cycle direction detection thresholds were 7.54 and 3.01 cm/s(2) for regular and irregular firing otolith afferents, respectively. Half-cycle thresholds were approximately double, with excitatory thresholds being half as large as inhibitory thresholds. The variability in threshold among afferents was directly related to neuronal gain and did not depend on spike count variance. The exact threshold values depended on both the time window used for spike count analysis and the filtering method used to calculate mean firing rate, although differences between regular and irregular afferent thresholds were independent of analysis parameters. The fact that minimum thresholds measured in macaque otolith afferents are of the same order of magnitude as human behavioral thresholds suggests that the vestibular periphery might determine the limit on our ability to detect or discriminate small differences in head movement, with little noise added during downstream processing.

Stress lowers the detection threshold for foul-smelling 2-mercaptoethanol.

Science.gov (United States)

Pacharra, Marlene; Schäper, Michael; Kleinbeck, Stefan; Blaszkewicz, Meinolf; Wolf, Oliver T; van Thriel, Christoph

2016-01-01

Previous studies have reported enhanced vigilance for threat-related information in response to acute stress. While it is known that acute stress modulates sensory systems in humans, its impact on olfaction and the olfactory detection of potential threats is less clear. Two psychophysical experiments examined, if acute stress lowers the detection threshold for foul-smelling 2-mercaptoethanol. Participants in Experiment 1 (N = 30) and Experiment 2 (N = 32) were randomly allocated to a control group or a stress group. Participants in the stress group underwent a purely psychosocial stressor (public mental arithmetic) in Experiment 1 and a stressor that combined a physically demanding task with social-evaluative threat in Experiment 2 (socially evaluated cold-pressor test). In both experiments, olfactory detection thresholds were repeatedly assessed by means of dynamic dilution olfactometry. Each threshold measurement consisted of three trials conducted using an ascending method of limits. Participants in the stress groups showed the expected changes in heart rate, salivary cortisol, and mood measures in response to stress. About 20 min after the stressor, participants in the stress groups could detect 2-mercaptoethanol at a lower concentration than participants in the corresponding control groups. Our results show that acute stress lowers the detection threshold for a malodor.

Rainfall threshold calculation for debris flow early warning in areas with scarcity of data

Science.gov (United States)

Pan, Hua-Li; Jiang, Yuan-Jun; Wang, Jun; Ou, Guo-Qiang

2018-05-01

Debris flows are natural disasters that frequently occur in mountainous areas, usually accompanied by serious loss of lives and properties. One of the most commonly used approaches to mitigate the risk associated with debris flows is the implementation of early warning systems based on well-calibrated rainfall thresholds. However, many mountainous areas have little data regarding rainfall and hazards, especially in debris-flow-forming regions. Therefore, the traditional statistical analysis method that determines the empirical relationship between rainstorms and debris flow events cannot be effectively used to calculate reliable rainfall thresholds in these areas. After the severe Wenchuan earthquake, there were plenty of deposits deposited in the gullies, which resulted in several debris flow events. The triggering rainfall threshold has decreased obviously. To get a reliable and accurate rainfall threshold and improve the accuracy of debris flow early warning, this paper developed a quantitative method, which is suitable for debris flow triggering mechanisms in meizoseismal areas, to identify rainfall threshold for debris flow early warning in areas with a scarcity of data based on the initiation mechanism of hydraulic-driven debris flow. First, we studied the characteristics of the study area, including meteorology, hydrology, topography and physical characteristics of the loose solid materials. Then, the rainfall threshold was calculated by the initiation mechanism of the hydraulic debris flow. The comparison with other models and with alternate configurations demonstrates that the proposed rainfall threshold curve is a function of the antecedent precipitation index (API) and 1 h rainfall. To test the proposed method, we selected the Guojuanyan gully, a typical debris flow valley that during the 2008-2013 period experienced several debris flow events, located in the meizoseismal areas of the Wenchuan earthquake, as a case study. The comparison with other

Mean free path of electrons in rare gas solids

International Nuclear Information System (INIS)

Schwentner, N.

1976-07-01

The energy distribution of photoelectrons of solid Ar, Kr and Xe films with thickness between 10 A and 300 A have been measured in the photon energy range 10 eV to 30 eV using the synchrotron radiation of DESY. By varying the photon energy and the film thickness the dependence of the electron-electron scattering length on the electron kinetic energy has been determined. The mean free path for inelastic electron-electron scattering decreases monotonically from values of the order of 1.000 A at the scattering threshold to values between 1 A and 5 A for electron energies 10 eV above threshold. The observed energy dependence can be understood by a simplified bandstructure and a scattering probability described by a product of density of states. The threshold energy for electron-electron scattering lies between twice the energy of the n = 1 excitons and the sum of bandgap and exciton energy. (HK) [de

Comparison on taste threshold between adult male white cigarette and clove cigarette smokers using Murphy clinical test method

Directory of Open Access Journals (Sweden)

Ronald Reyses Tapilatu

2008-03-01

Full Text Available The habit of smoking white cigarettes and clove cigarettes may affect the gustatory function, that is, it will cause damage to taste buds, resulting in an increase in gustatory threshold. This research used the descriptive comparative method and had the purpose of obtaining an illustration of gustatory threshold and compare gustatory threshold in white cigarette smokers and clove cigarette smokers in young, male adults. For gustatory threshold evaluation, the Murphy method was used to obtain a value for perception threshold and taste identification threshold using sucrose solution of 0.0006 M-0.06 M concentration. Research results indicate that the perception threshold and identification threshold of young, male adult smokers are 0.0119 M and 0.0292 M. Young, male adult clove cigarette smokers have a perception threshold and identification threshold of 0.0151 M and 0.0348 M. The conclusion of this research is that the perception threshold of young, male adult white cigarette smokers and clove cigarette smokers are the same, whereas the identification threshold of young, male adult white cigarette smokers and clove cigarette smokers are different, that is, the identification threshold of clove cigarette smokers is higher than that of white cigarette smokers.

Effects of Bio solids Application on Pasture and Grape Vines in South-Eastern Australia

International Nuclear Information System (INIS)

Nash, D.; Butler, C.; Cody, J.; Warne, M.S.J.; McLaughlin, M.J.; Heemsbergen, D.; Broos, K.; McLaughlin, M.J.; Heemsbergen, D.; Broos, K.; Bell, M.; Barry, G.; Pritchard, D.; Penny, N.; Penny, N.

2011-01-01

Bio solids were applied to a pasture and a vineyard in south-eastern Australia. At both sites, soil Cd, Cu, and Zn concentrations linearly increased with bio solids application rates although not to the extent of exceeding soil quality guidelines. Bio solids marginally increased soil C and N concentrations at the pasture site but significantly increased P concentrations. With lower overall soil fertility at the vineyard, bio solids increased C, N, and P concentrations. At neither site did bio solids application affect soil microbial endpoints. Bio solids increased pasture production compared to the unfertilised control but had little effect on grape production or quality. Interestingly, over the 3-year trial, there was no difference in pasture production between the bio solids treated plots and plots receiving inorganic fertiliser. These results suggest that bio solids could be used as a fertiliser to stimulate pasture production and as a soil conditioner to improve vineyard soils in this region.

Scientific substantination of maximum allowable concentration of fluopicolide in water

Directory of Open Access Journals (Sweden)

Pelo I.М.

2014-03-01

Full Text Available In order to substantiate fluopicolide maximum allowable concentration in the water of water reservoirs the research was carried out. Methods of study: laboratory hygienic experiment using organoleptic and sanitary-chemical, sanitary-toxicological, sanitary-microbiological and mathematical methods. The results of fluopicolide influence on organoleptic properties of water, sanitary regimen of reservoirs for household purposes were given and its subthreshold concentration in water by sanitary and toxicological hazard index was calculated. The threshold concentration of the substance by the main hazard criteria was established, the maximum allowable concentration in water was substantiated. The studies led to the following conclusions: fluopicolide threshold concentration in water by organoleptic hazard index (limiting criterion – the smell – 0.15 mg/dm3, general sanitary hazard index (limiting criteria – impact on the number of saprophytic microflora, biochemical oxygen demand and nitrification – 0.015 mg/dm3, the maximum noneffective concentration – 0.14 mg/dm3, the maximum allowable concentration - 0.015 mg/dm3.

Assessment of the health risks and odor concentration of volatile compounds from a municipal solid waste landfill in China.

Science.gov (United States)

Wu, Chuandong; Liu, Jiemin; Liu, Shihua; Li, Wenhui; Yan, Luchun; Shu, Mushui; Zhao, Peng; Zhou, Peng; Cao, Wenbin

2018-07-01

Municipal solid waste (MSW) landfills are a source of odorous and toxic compounds. In this work, we present an integrated assessment of the odor concentration and human health risks of volatile compounds to evaluate the environmental quality at a MSW landfill. Air samples were collected seasonally from six areas of the landfill with different functions. The total concentrations of the compounds ranged from 204.0 to 7426.7 μg m -3 , and the concentrations in temporarily and permanently capped areas were 50.3 and 83.4% lower than those in the tipping area, respectively. The odor concentration was greatest at the leachate collection tank (1732-6254 ou E m -3 ) and tipping area (1573-4113 ou E m -3 ) and was mainly caused by hydrogen sulfide (57.9 and 49.1%, respectively). Moreover, the odor concentration was positively correlated with the temperature (r = 0.500, p waste areas exceeded acceptable levels. Moreover, the cumulative HI (2.5-5.7) and R (1.0E-04 to 3.4E-04) in the waste areas should receive special attention since they were above acceptable levels during all of the seasons. Aromatic and halogenated compounds dominated the cumulative R, accounting for 79 and 21% of the total, on average, while for the cumulative HI, sulfur compounds contributed the most (67%). Copyright © 2018 Elsevier Ltd. All rights reserved.

In-vivo singlet oxygen threshold doses for PDT.

Science.gov (United States)

Zhu, Timothy C; Kim, Michele M; Liang, Xing; Finlay, Jarod C; Busch, Theresa M

2015-02-01

Dosimetry of singlet oxygen ( 1 O 2 ) is of particular interest because it is the major cytotoxic agent causing biological effects for type-II photosensitizers during photodynamic therapy (PDT). An in-vivo model to determine the singlet oxygen threshold dose, [ 1 O 2 ] rx,sh , for PDT was developed. An in-vivo radiation-induced fibrosarcoma (RIF) tumor mouse model was used to correlate the radius of necrosis to the calculation based on explicit PDT dosimetry of light fluence distribution, tissue optical properties, and photosensitizer concentrations. Inputs to the model include five photosensitizer-specific photochemical parameters along with [ 1 O 2 ] rx,sh . Photosensitizer-specific model parameters were determined for benzoporphyrin derivative monoacid ring A (BPD) and compared with two other type-II photosensitizers, Photofrin ® and m-tetrahydroxyphenylchlorin (mTHPC) from the literature. The mean values (standard deviation) of the in-vivo [ 1 O 2 ] rx,sh are approximately 0.56 (0.26) and 0.72 (0.21) mM (or 3.6×10 7 and 4.6×10 7 singlet oxygen per cell to reduce the cell survival to 1/e) for Photofrin ® and BPD, respectively, assuming that the fraction of generated singlet oxygen that interacts with the cell is 1. While the values for the photochemical parameters (ξ, σ, g , β) used for BPD were preliminary and may need further refinement, there is reasonable confidence for the values of the singlet oxygen threshold doses. In comparison, the [ 1 O 2 ] rx,sh value derived from in-vivo mouse study was reported to be 0.4 mM for mTHPC-PDT. However, the singlet oxygen required per cell is reported to be 9×10 8 per cell per 1/ e fractional kill in an in-vitro mTHPC-PDT study on a rat prostate cancer cell line (MLL cells) and is reported to be 7.9 mM for a multicell in-vitro EMT6/Ro spheroid model for mTHPC-PDT. A theoretical analysis is provided to relate the number of in-vitro singlet oxygen required per cell to reach cell killing of 1/ e to in-vivo singlet

Determination of the activity concentration of a 238 Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly.

Science.gov (United States)

Aguiar, Julio C; Galiano, Eduardo; Arenillas, Pablo

2005-08-01

The activity concentration of a (238)Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb alpha particles, but reduce their energy by an average of 22 keV.A mean activity concentration for (238)Pu of 359.10+/-0.8 kBq/g was measured.

Determination of the activity concentration of a 238Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly

International Nuclear Information System (INIS)

Aguiar, Julio C.; Galiano, Eduardo; Arenillas, Pablo

2005-01-01

The activity concentration of a 238 Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb α particles, but reduce their energy by an average of 22keV.A mean activity concentration for 238 Pu of 359.10+/-0.8kBq/g was measured

Effective medium of periodic fluid-solid composites

KAUST Repository

Mei, Jun; Wu, Ying; Liu, Zhengyou

2012-01-01

An analytic solution of the effective mass density and bulk modulus of a periodic fluid-solid composite is obtained by using the multiple-scattering theory in the long-wavelength limit. It is shown that when the concentration of solid inclusions

Intermediate structure and threshold phenomena

International Nuclear Information System (INIS)

Hategan, Cornel

2004-01-01

The Intermediate Structure, evidenced through microstructures of the neutron strength function, is reflected in open reaction channels as fluctuations in excitation function of nuclear threshold effects. The intermediate state supporting both neutron strength function and nuclear threshold effect is a micro-giant neutron threshold state. (author)

Optimization of moistening solution concentration on xylanase activity in solid state fermentation from oil palm empty fruit bunches

Science.gov (United States)

Mardawati, Efri; Parlan; Rialita, Tita; Nurhadi, Bambang

2018-03-01

Xylanase is an enzyme used in the industrial world, including food industry. Xylanase can be utilized as a 1,4-β-xylosidic endo-hydrolysis catalyst of xylanase, a hemicellulose component for obtaining a xylose monomer. This study aims to determine the optimum concentration of the fermentation medium using Response Surface Method (RSM) in the production of xylanase enzyme from oil palm empty fruit bunches (OPEFB) through solid state fermentation process. The variables varied in this study used factor A (ammonium sulphate concentration 1.0-2.0 g/L), B (concentration of potassium dihydrogen phosphate 1.5-2.5 g/L) and C (urea concentration 0.2 – 0.5 g/L). The data was analysed by using Design Expert version 10.0.1.0 especially CCD with total 17 running including 3 times replicated of canter point. Trichoderma viride was used for the process production of xylanase enzyme. The ratio between substrate and moistening solution used was 0.63 g / mL with temperature of 32.80C, 60 h incubation time. The analysis of enzyme activity was done by DNS method with 1% xylan as substrate. Analysis of protein content in enzyme was done by Bradford method. The optimum of moistening solution concentration in this fermentation was obtained. They are, the ammonium sulphate concentration of 1.5 g/L, potassium dihydrogen phosphate 2.0 g/L and urea 0.35 g/L with activity of 684.70 U/mL, specific activity enzyme xylanase 6261.58 U/mg, protein content 0.1093 U/mg, the model was validated using experiment design with perfect reliability value 0.96.

Threshold values characterizing iodine-induced SCC of zircaloys

International Nuclear Information System (INIS)

Une, K.

1981-01-01

In this paper, threshold values of stress, stress intensity factor, strain, strain rate and iodine concentration for SCC of unirradiated and irradiated Zircaloys are reviewed. The ratio of σ sub(th)/σ sub(y) adequately represents the effects of cold-work and irradiation on the SCC susceptibility, where threshold stress σ sub(th) is defined as the minimum stress to cause SCC to failure after 10-20 hours and σ sub(y), the yield stress obtained in an inert atmosphere. The ratio becomes gradually smaller with larger σ sub(y) and is less than 1 for materials with yield strengths above about 350MPa. Plastic strain appears to be necessary for SCC; plastic strains to failure range from 0.1 to 1% for high strength materials, even when data for irradiated materials are included. Strain rate significantly affects the susceptibility. A comparison of SCC data between constant strain rate and constant stress tests is presented. (author)

Optimization of artificial neural network models through genetic algorithms for surface ozone concentration forecasting.

Science.gov (United States)

Pires, J C M; Gonçalves, B; Azevedo, F G; Carneiro, A P; Rego, N; Assembleia, A J B; Lima, J F B; Silva, P A; Alves, C; Martins, F G

2012-09-01

This study proposes three methodologies to define artificial neural network models through genetic algorithms (GAs) to predict the next-day hourly average surface ozone (O(3)) concentrations. GAs were applied to define the activation function in hidden layer and the number of hidden neurons. Two of the methodologies define threshold models, which assume that the behaviour of the dependent variable (O(3) concentrations) changes when it enters in a different regime (two and four regimes were considered in this study). The change from one regime to another depends on a specific value (threshold value) of an explanatory variable (threshold variable), which is also defined by GAs. The predictor variables were the hourly average concentrations of carbon monoxide (CO), nitrogen oxide, nitrogen dioxide (NO(2)), and O(3) (recorded in the previous day at an urban site with traffic influence) and also meteorological data (hourly averages of temperature, solar radiation, relative humidity and wind speed). The study was performed for the period from May to August 2004. Several models were achieved and only the best model of each methodology was analysed. In threshold models, the variables selected by GAs to define the O(3) regimes were temperature, CO and NO(2) concentrations, due to their importance in O(3) chemistry in an urban atmosphere. In the prediction of O(3) concentrations, the threshold model that considers two regimes was the one that fitted the data most efficiently.

Radionuclide solubility control by solid solutions

Energy Technology Data Exchange (ETDEWEB)

Brandt, F.; Klinkenberg, M.; Rozov, K.; Bosbach, D. [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research - Nuclear Waste Management and Reactor Safety (IEK-6); Vinograd, V. [Frankfurt Univ. (Germany). Inst. of Geosciences

2015-07-01

The migration of radionuclides in the geosphere is to a large extend controlled by sorption processes onto minerals and colloids. On a molecular level, sorption phenomena involve surface complexation, ion exchange as well as solid solution formation. The formation of solid solutions leads to the structural incorporation of radionuclides in a host structure. Such solid solutions are ubiquitous in natural systems - most minerals in nature are atomistic mixtures of elements rather than pure compounds because their formation leads to a thermodynamically more stable situation compared to the formation of pure compounds. However, due to a lack of reliable data for the expected scenario at close-to equilibrium conditions, solid solution systems have so far not been considered in long-term safety assessments for nuclear waste repositories. In recent years, various solid-solution aqueous solution systems have been studied. Here we present state-of-the art results regarding the formation of (Ra,Ba)SO{sub 4} solid solutions. In some scenarios describing a waste repository system for spent nuclear fuel in crystalline rocks {sup 226}Ra dominates the radiological impact to the environment associated with the potential release of radionuclides from the repository in the future. The solubility of Ra in equilibrium with (Ra,Ba)SO{sub 4} is much lower than the one calculated with RaSO{sub 4} as solubility limiting phase. Especially, the available literature data for the interaction parameter W{sub BaRa}, which describes the non-ideality of the solid solution, vary by about one order of magnitude (Zhu, 2004; Curti et al., 2010). The final {sup 226}Ra concentration in this system is extremely sensitive to the amount of barite, the difference in the solubility products of the end-member phases, and the degree of non-ideality of the solid solution phase. Here, we have enhanced the fundamental understanding regarding (1) the thermodynamics of (Ra,Ba)SO{sub 4} solid solutions and (2) the

Nuclear threshold effects and neutron strength function

International Nuclear Information System (INIS)

Hategan, Cornel; Comisel, Horia

2003-01-01

One proves that a Nuclear Threshold Effect is dependent, via Neutron Strength Function, on Spectroscopy of Ancestral Neutron Threshold State. The magnitude of the Nuclear Threshold Effect is proportional to the Neutron Strength Function. Evidence for relation of Nuclear Threshold Effects to Neutron Strength Functions is obtained from Isotopic Threshold Effect and Deuteron Stripping Threshold Anomaly. The empirical and computational analysis of the Isotopic Threshold Effect and of the Deuteron Stripping Threshold Anomaly demonstrate their close relationship to Neutron Strength Functions. It was established that the Nuclear Threshold Effects depend, in addition to genuine Nuclear Reaction Mechanisms, on Spectroscopy of (Ancestral) Neutron Threshold State. The magnitude of the effect is proportional to the Neutron Strength Function, in their dependence on mass number. This result constitutes also a proof that the origins of these threshold effects are Neutron Single Particle States at zero energy. (author)

Differential reconstructed gene interaction networks for deriving toxicity threshold in chemical risk assessment.

Science.gov (United States)

Yang, Yi; Maxwell, Andrew; Zhang, Xiaowei; Wang, Nan; Perkins, Edward J; Zhang, Chaoyang; Gong, Ping

2013-01-01

Pathway alterations reflected as changes in gene expression regulation and gene interaction can result from cellular exposure to toxicants. Such information is often used to elucidate toxicological modes of action. From a risk assessment perspective, alterations in biological pathways are a rich resource for setting toxicant thresholds, which may be more sensitive and mechanism-informed than traditional toxicity endpoints. Here we developed a novel differential networks (DNs) approach to connect pathway perturbation with toxicity threshold setting. Our DNs approach consists of 6 steps: time-series gene expression data collection, identification of altered genes, gene interaction network reconstruction, differential edge inference, mapping of genes with differential edges to pathways, and establishment of causal relationships between chemical concentration and perturbed pathways. A one-sample Gaussian process model and a linear regression model were used to identify genes that exhibited significant profile changes across an entire time course and between treatments, respectively. Interaction networks of differentially expressed (DE) genes were reconstructed for different treatments using a state space model and then compared to infer differential edges/interactions. DE genes possessing differential edges were mapped to biological pathways in databases such as KEGG pathways. Using the DNs approach, we analyzed a time-series Escherichia coli live cell gene expression dataset consisting of 4 treatments (control, 10, 100, 1000 mg/L naphthenic acids, NAs) and 18 time points. Through comparison of reconstructed networks and construction of differential networks, 80 genes were identified as DE genes with a significant number of differential edges, and 22 KEGG pathways were altered in a concentration-dependent manner. Some of these pathways were perturbed to a degree as high as 70% even at the lowest exposure concentration, implying a high sensitivity of our DNs approach

Linear and nonlinear optical absorption coefficients in GaAs/Ga1−xAlxAs concentric double quantum rings: Effects of hydrostatic pressure and aluminum concentration

International Nuclear Information System (INIS)

Baghramyan, H.M.; Barseghyan, M.G.; Kirakosyan, A.A.; Restrepo, R.L.; Duque, C.A.

2013-01-01

The linear and nonlinear intra-band optical absorption coefficients in GaAs/Ga 1−x Al x As two-dimensional concentric double quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and aluminum concentration the energies of the ground (n=1,l=0) and the first excited state (n=2,l=1) have been found using the effective mass approximation and the transfer matrix formalism. The energies of these states and the corresponding threshold energy of the intra-band optical transitions are examined as a function of hydrostatic pressure and aluminum concentration for different sizes of the structure. We also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as functions of the incident photon energy for different values of hydrostatic pressure, aluminum concentration, sizes of the structure, and incident optical intensity. Its is found that the effects of the hydrostatic pressure and the aluminum concentration lead to a shifting of the resonant peaks of the intra-band optical spectrum. - Highlights: ► Linear and nonlinear intra-band absorption in quantum rings. ► Threshold energy strongly depends on the hydrostatic pressure. ► Threshold energy strongly depends on the stoichiometry and sizes of structure. ► Optical absorption is affected by the incident optical intensity.

Carbon-based strong solid acid for cornstarch hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Nata, Iryanti Fatyasari, E-mail: yanti_tkunlam@yahoo.com [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Irawan, Chairul; Mardina, Primata [Chemical Engineering Study Program, Faculty of Engineering, Lambung Mangkurat University, Jl. A. Yani Km. 36 Banjarbaru, South Kalimantan 70714 (Indonesia); Lee, Cheng-Kang, E-mail: cklee@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University of Science and Technology, 43 Keelung Rd. Sec.4, Taipei 106, Taiwan (China)

2015-10-15

Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO{sub 3}H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO{sub 3}H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use.

Carbon-based strong solid acid for cornstarch hydrolysis

International Nuclear Information System (INIS)

Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

2015-01-01

Highly sulfonated carbonaceous spheres with diameter of 100–500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO 3 H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO 3 H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst. - Highlights: • Carbon solid acid was successfully prepared by one-step hydrothermal carbonization. • The acrylic acid as monomer was effectively reduce the diameter size of particle. • The solid acid catalyst show good catalytic performance of starch hydrolysis. • The solid acid catalyst is not significantly deteriorated after repeated use

Automatic Semiconductor Wafer Image Segmentation for Defect Detection Using Multilevel Thresholding

Directory of Open Access Journals (Sweden)

Saad N.H.

2016-01-01

Full Text Available Quality control is one of important process in semiconductor manufacturing. A lot of issues trying to be solved in semiconductor manufacturing industry regarding the rate of production with respect to time. In most semiconductor assemblies, a lot of wafers from various processes in semiconductor wafer manufacturing need to be inspected manually using human experts and this process required full concentration of the operators. This human inspection procedure, however, is time consuming and highly subjective. In order to overcome this problem, implementation of machine vision will be the best solution. This paper presents automatic defect segmentation of semiconductor wafer image based on multilevel thresholding algorithm which can be further adopted in machine vision system. In this work, the defect image which is in RGB image at first is converted to the gray scale image. Median filtering then is implemented to enhance the gray scale image. Then the modified multilevel thresholding algorithm is performed to the enhanced image. The algorithm worked in three main stages which are determination of the peak location of the histogram, segmentation the histogram between the peak and determination of first global minimum of histogram that correspond to the threshold value of the image. The proposed approach is being evaluated using defected wafer images. The experimental results shown that it can be used to segment the defect correctly and outperformed other thresholding technique such as Otsu and iterative thresholding.

Relation of radiation damage of metallic solids to electronic structure. Pt. 5

International Nuclear Information System (INIS)

Shalaev, A.M.; Adamenko, A.A.

1977-01-01

The problem of relating a damage in metal solids to the parameters of radiation fluxes and the physical nature of a target is considered. Basing upon experimental and theoretical investigations into the processes of interaction of particle fluxes with solids, the following conclusions have been reached. Threshold energy of ion displacement in the crystal lattice of a metal solid is dependent on the energy of a bombarding particle, which is due to ionization and electroexcitation stimulated by energy transfer from a fast particle to a system of collectivized electrons. The rate of metal solid damage by radiation depends on the state of the crystal lattice, in particular on its defectness. Variations of local electron density in the vicinity of a defect are related with changing thermodynamic characteristics of radiation-induced defect formation. A type of atomic bond in a solid affects the rate of radiation damage. The greatest damage occurs in materials with a covalent bond

A New Wavelet Threshold Function and Denoising Application

Directory of Open Access Journals (Sweden)

Lu Jing-yi

2016-01-01

Full Text Available In order to improve the effects of denoising, this paper introduces the basic principles of wavelet threshold denoising and traditional structures threshold functions. Meanwhile, it proposes wavelet threshold function and fixed threshold formula which are both improved here. First, this paper studies the problems existing in the traditional wavelet threshold functions and introduces the adjustment factors to construct the new threshold function basis on soft threshold function. Then, it studies the fixed threshold and introduces the logarithmic function of layer number of wavelet decomposition to design the new fixed threshold formula. Finally, this paper uses hard threshold, soft threshold, Garrote threshold, and improved threshold function to denoise different signals. And the paper also calculates signal-to-noise (SNR and mean square errors (MSE of the hard threshold functions, soft thresholding functions, Garrote threshold functions, and the improved threshold function after denoising. Theoretical analysis and experimental results showed that the proposed approach could improve soft threshold functions with constant deviation and hard threshold with discontinuous function problems. The proposed approach could improve the different decomposition scales that adopt the same threshold value to deal with the noise problems, also effectively filter the noise in the signals, and improve the SNR and reduce the MSE of output signals.

The Glare Effect Test and the Impact of Age on Luminosity Thresholds

Directory of Open Access Journals (Sweden)

Alessio Facchin

2017-06-01

Full Text Available The glare effect (GE is an illusion in which a white region appears self-luminous when surrounded by linearly decreasing luminance ramps. It has been shown that the magnitude of the luminosity effect can be modulated by manipulating the luminance range of the gradients. In the present study we tested the thresholds for the GE on two groups of adults: young (20–30 years old and elderly (60–75 years old. Purpose of our perspective study was to test the possibility of transforming the GE into a test that could easily measure thresholds for luminosity and discomfort glare. The Glare Effect Test (GET consisted in 101 printed cards that differed from each other for the range of luminance ramps. Participants were assessed with GET and a battery of visual tests: visual acuity, contrast sensitivity, illusion of length perception, and Ishihara test. Specifically in the GET, participants were required to classify cards on the basis of two reference cards (solid black-no gradient; full range black to white gradient. PSEs of the GE show no correlation with the other visual tests, revealing a divergent validity. A significant difference between young and elderly was found: contrary to our original expectations, luminosity thresholds of GE for elderly were higher than those for young, suggesting a non-direct relationship between luminosity perception and discomfort glare.

Laser-solid interaction and dynamics of the laser-ablated materials

International Nuclear Information System (INIS)

Chen, K.R.; Leboeuf, J.N.; Geohegan, D.B.; Wood, R.F.; Donato, J.M.; Liu, C.L.; Puretzky, A.A.

1995-01-01

Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the authors' thermal model with the Clausius-Clapeyron equation to determine the vaporization temperature under different surface pressure condition. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models are coupled. Modeling results show that lower background pressure results lower laser energy density threshold for vaporization. The ablation rate and the amount of materials removed are proportional to the laser energy density above its threshold. The authors also demonstrate a dynamic source effect that accelerates the unsteady expansion of laser-ablated material in the direction perpendicular to the solid. A dynamic partial ionization effect is studied as well. A self-similar theory shows that the maximum expansion velocity is proportional to c s α, where 1 - α is the slope of the velocity profile. Numerical hydrodynamic modeling is in good agreement with the theory. With these effects, α is reduced. Therefore, the expansion front velocity is significantly higher than that from conventional models. The results are consistent with experiments. They further study how the plume propagates in high background gas condition. Under appropriate conditions, the plume is slowed down, separates with the background, is backward moving, and hits the solid surface. Then, it splits into two parts when it rebounds from the surface. The results from the modeling will be compared with experimental observations where possible

Molecular and solid-state properties of tris-(8-hydroxyquinolate)-aluminum

International Nuclear Information System (INIS)

Martin, Richard L.; Kress, Joel D.; Campbell, I. H.; Smith, D. L.

2000-01-01

We use a hybrid density-functional-theory approach to calculate ground-state electronic properties and a time-dependent density-functional-theory approach to investigate the excited state electronic properties of molecular tris-(8-hydroxyquinolate)-aluminum, Alq. The calculated molecular results are compared with measurements on dense solid-state films of Alq. We specifically consider: the optical absorption spectrum near the fundamental absorption threshold, the ionization potential, the single-particle energy gap, the static dielectric constant, and the electric-field dependence of the electron mobility. We find that the molecular calculations can describe the optical absorption spectrum near the fundamental absorption threshold without significant corrections for solid-state effects. The energies of the triplet excited states are computed and the lowest triplet is found to lie 0.64 eV below the lowest excited singlet state. In contrast, large dielectric corrections must be included for the molecular calculations to describe the ionization potential and single-particle energy gap. When these dielectric corrections are made, using the calculated molecular polarizability, which accurately gives the measured static dielectric constant, both the ionization potential and single-particle energy gap are well described. The calculated molecular dipole moment can be used to interpret the electric-field dependence of the electron mobility. The solid-state properties, determined from the molecular calculations, are then used in a device model to describe the measured current-voltage characteristics in Alq diodes. (c) 2000 The American Physical Society

Nonimaging optical concentrators using graded-index dielectric.

Science.gov (United States)

Zitelli, M

2014-04-01

A new generation of inhomogeneous nonimaging optical concentrators is proposed, able to achieve simultaneously high optical efficiency and acceptance solid angle at a given geometrical concentration factor. General design methods are given, and concentrators are numerically investigated and optimized.

Surface phase transitions in cu-based solid solutions

Science.gov (United States)

Zhevnenko, S. N.; Chernyshikhin, S. V.

2017-11-01

We have measured surface energy in two-component Cu-based systems in H2 + Ar gas atmosphere. The experiments on solid Cu [Ag] and Cu [Co] solutions show presence of phase transitions on the surfaces. Isotherms of the surface energy have singularities (the minimum in the case of copper solid solutions with silver and the maximum in the case of solid solutions with cobalt). In both cases, the surface phase transitions cause deficiency of surface miscibility: formation of a monolayer (multilayer) (Cu-Ag) or of nanoscale particles (Cu-Co). At the same time, according to the volume phase diagrams, the concentration and temperature of the surface phase transitions correspond to the solid solution within the volume. The method permits determining the rate of diffusional creep in addition to the surface energy. The temperature and concentration dependence of the solid solutions' viscosity coefficient supports the fact of the surface phase transitions and provides insights into the diffusion properties of the transforming surfaces.

Stochastic generation of explicit pore structures by thresholding Gaussian random fields

Energy Technology Data Exchange (ETDEWEB)

Hyman, Jeffrey D., E-mail: jhyman@lanl.gov [Program in Applied Mathematics, University of Arizona, Tucson, AZ 85721-0089 (United States); Computational Earth Science, Earth and Environmental Sciences (EES-16), and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87544 (United States); Winter, C. Larrabee, E-mail: winter@email.arizona.edu [Program in Applied Mathematics, University of Arizona, Tucson, AZ 85721-0089 (United States); Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721-0011 (United States)

2014-11-15

We provide a description and computational investigation of an efficient method to stochastically generate realistic pore structures. Smolarkiewicz and Winter introduced this specific method in pores resolving simulation of Darcy flows (Smolarkiewicz and Winter, 2010 [1]) without giving a complete formal description or analysis of the method, or indicating how to control the parameterization of the ensemble. We address both issues in this paper. The method consists of two steps. First, a realization of a correlated Gaussian field, or topography, is produced by convolving a prescribed kernel with an initial field of independent, identically distributed random variables. The intrinsic length scales of the kernel determine the correlation structure of the topography. Next, a sample pore space is generated by applying a level threshold to the Gaussian field realization: points are assigned to the void phase or the solid phase depending on whether the topography over them is above or below the threshold. Hence, the topology and geometry of the pore space depend on the form of the kernel and the level threshold. Manipulating these two user prescribed quantities allows good control of pore space observables, in particular the Minkowski functionals. Extensions of the method to generate media with multiple pore structures and preferential flow directions are also discussed. To demonstrate its usefulness, the method is used to generate a pore space with physical and hydrological properties similar to a sample of Berea sandstone. -- Graphical abstract: -- Highlights: •An efficient method to stochastically generate realistic pore structures is provided. •Samples are generated by applying a level threshold to a Gaussian field realization. •Two user prescribed quantities determine the topology and geometry of the pore space. •Multiple pore structures and preferential flow directions can be produced. •A pore space based on Berea sandstone is generated.

Contribution to the study of solid state diffusion in concentrated alloys - A case study of the Fe - Pd system

International Nuclear Information System (INIS)

Gomez Jaen, Juan Pedro

1973-01-01

The study of diffusion in concentrated alloys presents two main aspects: 1) The search for an adequate theoretical framework; 2) The carrying out of experiments with a view towards verification of the theory. From the theoretical standpoint it is shown that the atomic theory of diffusion, as formulated by MANNING, can be linked to the phenomenological theory of HOWARD and LIDIARD. Thus it is seen that the vacancy flow effect is really a cross correlation effect and, that the phenomenological ONSAGER coefficients can be expressed as functions of the correlation factors. From the experimental side, a number of experiments were performed on the Fe - Pd System, including experiments on interdiffusion, the KIRKENDALL effect, diffusion of Fe 59 and Pd 103 isotopes in homogeneous Fe - Pd alloys, and the diffusion of these isotopes in the concentration gradient. We introduce a perfected method for taking account of the changes in the molar volume of the alloy expressed as a function of the concentration, throughout the diffusion process. The experiments enabled us to obtain the different diffusion coefficients, correlation factors, and partial mobilities, thus allowing a precise knowledge of the Fe - Pd solid state diffusion system.(author) [fr

Magnetotelluric Detection Thresholds as a Function of Leakage Plume Depth, TDS and Volume

Energy Technology Data Exchange (ETDEWEB)

Yang, X. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buscheck, T. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mansoor, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Carroll, S. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-04-21

We conducted a synthetic magnetotelluric (MT) data analysis to establish a set of specific thresholds of plume depth, TDS concentration and volume for detection of brine and CO₂ leakage from legacy wells into shallow aquifers in support of Strategic Monitoring Subtask 4.1 of the US DOE National Risk Assessment Partnership (NRAP Phase II), which is to develop geophysical forward modeling tools. 900 synthetic MT data sets span 9 plume depths, 10 TDS concentrations and 10 plume volumes. The monitoring protocol consisted of 10 MT stations in a 2×5 grid laid out along the flow direction. We model the MT response in the audio frequency range of 1 Hz to 10 kHz with a 50 Ωm baseline resistivity and the maximum depth up to 2000 m. Scatter plots show the MT detection thresholds for a trio of plume depth, TDS concentration and volume. Plumes with a large volume and high TDS located at a shallow depth produce a strong MT signal. We demonstrate that the MT method with surface based sensors can detect a brine and CO₂ plume so long as the plume depth, TDS concentration and volume are above the thresholds. However, it is unlikely to detect a plume at a depth larger than 1000 m with the change of TDS concentration smaller than 10%. Simulated aquifer impact data based on the Kimberlina site provides a more realistic view of the leakage plume distribution than rectangular synthetic plumes in this sensitivity study, and it will be used to estimate MT responses over simulated brine and CO₂ plumes and to evaluate the leakage detectability. Integration of the simulated aquifer impact data and the MT method into the NRAP DREAM tool may provide an optimized MT survey configuration for MT data collection. This study presents a viable approach for sensitivity study of geophysical monitoring methods for leakage detection. The results come in handy for rapid assessment of leakage detectability.

Threshold behavior in electron-atom scattering

International Nuclear Information System (INIS)

Sadeghpour, H.R.; Greene, C.H.

1996-01-01

Ever since the classic work of Wannier in 1953, the process of treating two threshold electrons in the continuum of a positively charged ion has been an active field of study. The authors have developed a treatment motivated by the physics below the double ionization threshold. By modeling the double ionization as a series of Landau-Zener transitions, they obtain an analytical formulation of the absolute threshold probability which has a leading power law behavior, akin to Wannier's law. Some of the noteworthy aspects of this derivation are that the derivation can be conveniently continued below threshold giving rise to a open-quotes cuspclose quotes at threshold, and that on both sides of the threshold, absolute values of the cross sections are obtained

Bumblebees are not deterred by ecologically relevant concentrations of nectar toxins.

Science.gov (United States)

Tiedeken, Erin Jo; Stout, Jane C; Stevenson, Philip C; Wright, Geraldine A

2014-05-01

Bees visit flowers to collect nectar and pollen that contain nutrients and simultaneously facilitate plant sexual reproduction. Paradoxically, nectar produced to attract pollinators often contains deterrent or toxic plant compounds associated with herbivore defence. The functional significance of these nectar toxins is not fully understood, but they may have a negative impact on pollinator behaviour and health, and, ultimately, plant pollination. This study investigates whether a generalist bumblebee, Bombus terrestris, can detect naturally occurring concentrations of nectar toxins. Using paired-choice experiments, we identified deterrence thresholds for five compounds found in the nectar of bee-pollinated plants: quinine, caffeine, nicotine, amygdalin and grayanotoxin. The deterrence threshold was determined when bumblebees significantly preferred a sucrose solution over a sucrose solution containing the compound. Bumblebees had the lowest deterrence threshold for the alkaloid quinine (0.01 mmol l(-1)); all other compounds had higher deterrence thresholds, above the natural concentration range in floral nectar. Our data, combined with previous work using honeybees, suggest that generalist bee species have poor acuity for the detection of nectar toxins. The fact that bees do not avoid nectar-relevant concentrations of these compounds likely indicates that it is difficult for them to learn to associate floral traits with the presence of toxins, thus maintaining this trait in plant populations.

A space-charge treatment of the increased concentration of reactive species at the surface of a ceria solid solution

Energy Technology Data Exchange (ETDEWEB)

Zurhelle, Alexander F.; Souza, Roger A. de [Institute of Physical Chemistry, RWTH Aachen University (Germany); Tong, Xiaorui; Mebane, David S. [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, WV (United States); Klein, Andreas [Institute of Materials Science, TU Darmstadt (Germany)

2017-11-13

A space-charge theory applicable to concentrated solid solutions (Poisson-Cahn theory) was applied to describe quantitatively as a function of temperature and oxygen partial pressure published data obtained by in situ X-ray photoelectron spectroscopy (XPS) for the concentration of Ce{sup 3+} (the reactive species) at the surface of the oxide catalyst Ce{sub 0.8}Sm{sub 0.2}O{sub 1.9}. In contrast to previous theoretical treatments, these calculations clearly indicate that the surface is positively charged and compensated by an attendant negative space-charge zone. The high space-charge potential that develops at the surface (>0.8 V) is demonstrated to be hardly detectable by XPS measurements because of the short extent of the space-charge layer. This approach emphasizes the need to take into account defect interactions and to allow deviations from local charge neutrality when considering the surfaces of oxide catalysts. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Double Photoionization Near Threshold

Science.gov (United States)

Wehlitz, Ralf

2007-01-01

The threshold region of the double-photoionization cross section is of particular interest because both ejected electrons move slowly in the Coulomb field of the residual ion. Near threshold both electrons have time to interact with each other and with the residual ion. Also, different theoretical models compete to describe the double-photoionization cross section in the threshold region. We have investigated that cross section for lithium and beryllium and have analyzed our data with respect to the latest results in the Coulomb-dipole theory. We find that our data support the idea of a Coulomb-dipole interaction.

Determination of the activity concentration of a {sup 238}Pu solution by the defined solid angle method utilizing a novel dual diaphragm-detector assembly

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Julio C. [Departamento de Postgrado, Universidad Tecnologica Nacional, Buenos Aires (Argentina); Galiano, Eduardo [Departament of Physics, Laurentian University, Sudbury, Ont. P3E 2C6 (Canada)]. E-mail: egalianoriveros@laurentian.ca; Arenillas, Pablo [Comision Nacional de Energia Atomica, CAE, Laboratorio de Metrologia de Radioisotopos, Buenos Aires (Argentina)

2005-08-01

The activity concentration of a {sup 238}Pu solution was measured by the determined solid angle method employing a novel dual diaphragm-detector assembly, which has been previously described. Due to the special requirements of the detector, a new type of source holder was developed, which consisted of sandwiching the radioisotope between two organic films called VYNS. It was experimentally demonstrated that the VYNS films do not absorb {alpha} particles, but reduce their energy by an average of 22keV.A mean activity concentration for {sup 238}Pu of 359.10+/-0.8kBq/g was measured.

Analyzer for measurement of nitrogen oxide concentration by ozone content reduction in gas using solid state chemiluminescent sensor

Science.gov (United States)

Chelibanov, V. P.; Ishanin, G. G.; Isaev, L. N.

2014-05-01

Role of nitrogen oxide in ambient air is described and analyzed. New method of nitrogen oxide concentration measurement in gas phase is suggested based on ozone concentration measurement with titration by nitrogen oxide. Research of chemiluminescent sensor composition is carried out on experimental stand. The sensor produced on the base of solid state non-activated chemiluminescent composition is applied as ozone sensor. Composition is put on the surface of polymer matrix with developed surface. Sensor compositions includes gallic acid with addition of rodamine-6G. Model of interaction process between sensor composition and ozone has been developed, main products appeared during reaction are identified. The product determining the speed of luminescense appearance is found. This product belongs to quinone class. Then new structure of chemiluminescent composition was suggested, with absence of activation period and with high stability of operation. Experimental model of gas analyzer was constructed and operation algorithm was developed. It was demonstrated that developed NO measuring instrument would be applied for monitoring purposes of ambient air. This work was partially financially supported by Government of Russian Federation, Grant 074-U01

Carbon-based strong solid acid for cornstarch hydrolysis

Science.gov (United States)

Nata, Iryanti Fatyasari; Irawan, Chairul; Mardina, Primata; Lee, Cheng-Kang

2015-10-01

Highly sulfonated carbonaceous spheres with diameter of 100-500 nm can be generated by hydrothermal carbonization of glucose in the presence of hydroxyethylsulfonic acid and acrylic acid at 180 °C for 4 h. The acidity of the prepared carbonaceous sphere C4-SO3H can reach 2.10 mmol/g. It was used as a solid acid catalyst for the hydrolysis of cornstarch. Total reducing sugar (TRS) concentration of 19.91 mg/mL could be obtained by hydrolyzing 20 mg/mL cornstarch at 150 °C for 6 h using C4-SO3H as solid acid catalyst. The solid acid catalyst demonstrated good stability that only 9% decrease in TRS concentration was observed after five repeat uses. The as-prepared carbon-based solid acid catalyst can be an environmentally benign replacement for homogeneous catalyst.

Some particularities of impurity center structure in concentrated solid solutions MeF2-GdF3, where Me-Ca2+, Sr2+ and Ba2+

International Nuclear Information System (INIS)

Karelin, V.V.; Orlov, Yu.N.; Bozhevol'nov, V.E.; Ivanov, L.N.

1981-01-01

The monocrystalline CaF 2 -GdF 3 , SrF 2 -GdF 3 and BaF 2 -GdF 3 systems are studied using the methods of EPR, photo-, radio-, cathode- and thermoluminescence. It is shown that the structure of fluorite solid solutions changes considerably with the growth of the rare earth component concentration. At that, in the systems investigated at least three concentration regions can be singled out: (up to 1%; from 1 to 15%, and > 15% GdF 3 ) which are characterized by their certain selection of impurity centres [ru

Integrated pest management: theoretical insights from a threshold policy

Energy Technology Data Exchange (ETDEWEB)

Costa, Michel I. da Silveira [Laboratorio Nacional de Computacao Cientifica (LNCC), Petropolis, RJ (Brazil)], e-mail: michel@lncc.br; Faria, Lucas del B. [Universidade Federal de Lavras, MG (Brazil). Dept. de Biologia. Setor de Ecologia], e-mail: lucasdbf@gmail.com

2010-01-15

An Integrated Pest Management is formulated as a threshold policy. It is shown that when this strategy is applied to a food web consisting of generalist, specialist predators and endemic and pest prey, the dynamics can be stable and useful from the pest control point of view, despite the dynamical complexities inherent to the application of biocontrol only. In addition, pesticide toxicity depends rather on the species intrinsic parameters than on the chemical agent concentration. (author)

CFD simulation of solids suspension in stirred tanks: Review

Directory of Open Access Journals (Sweden)

Ochieng Aoyi

2010-01-01

Full Text Available Many chemical reactions are carried out using stirred tanks, and the efficiency of such systems depends on the quality of mixing, which has been a subject of research for many years. For solid-liquid mixing, traditionally the research efforts were geared towards determining mixing features such as off-bottom solid suspension using experimental techniques. In a few studies that focused on the determination of solids concentration distribution, some methods that have been used have not been accurate enough to account for some small scale flow mal-distribution such as the existence of dead zones. The present review shows that computational fluid dynamic (CFD techniques can be used to simulate mixing features such as solids off-bottom suspension, solids concentration and particle size distribution and cloud height. Information on the effects of particle size and particle size distribution on the solids concentration distribution is still scarce. Advancement of the CFD modeling is towards coupling the physical and kinetic data to capture mixing and reaction at meso- and micro-scales. Solids residence time distribution is important for the design; however, the current CFD models do not predict this parameter. Some advances have been made in recent years to apply CFD simulation to systems that involve fermentation and anaerobic processes. In these systems, complex interaction between the biochemical process and the hydrodynamics is still not well understood. This is one of the areas that still need more attention.

DC ionic conductivity of NaNO3: γ-Al2O3 composite solid electrolyte system

International Nuclear Information System (INIS)

Madhava Rao, M.V.; Narender Reddy, S.; Sadananda Chary, A.

2005-01-01

We present DC ionic conductivity measurements on composites formed between Na + ion conductor (NaNO 3 ) and dispersed insulating oxide (alumina). Enhancement of conductivity is noticed to increase with mole percent (m/o) of the dispersoid. The maximum enhancement observed is more than two orders of magnitude with respect to the host material. X-ray diffraction and differential scanning calorimetry studies ruled out the formation of solid solutions between the host material and the dispersoid. The experimental data indicating higher conductivity in dispersed system is interpreted in terms of the formation of space charge layer between the host material and the dispersoid in which defect concentration increases and that is thought to be the possible mechanism of conductivity enhancement. Activation energies obtained from the conductivity data in the extrinsic conduction region indicated least value for the systems at threshold mole percentage

Determination of submicrogram-per-liter concentrations of caffeine in surface water and groundwater samples by solid-phase extraction and liquid chromatography

Science.gov (United States)

Burkhardt, M.R.; Soliven, P.P.; Werner, S.L.; Vaught, D.G.

1999-01-01

A method for determining submicrogram-per-liter concentrations of caffeine in surface water and groundwater samples has been developed. Caffeine is extracted from a 1 L water sample with a 0.5 g graphitized carbon-based solid-phase cartridge, eluted with methylene chloride-methanol (80 + 20, v/v), and analyzed by liquid chromatography with photodiode-array detection. The single-operator method detection limit for organic-free water samples was 0.02 ??g/L. Mean recoveries and relative standard deviations were 93 ?? 13% for organicfree water samples fortified at 0.04 ??g/L and 84 ?? 4% for laboratory reagent spikes fortified at 0.5 ??g/L. Environmental concentrations of caffeine ranged from 0.003 to 1.44 ??g/L in surface water samples and from 0.01 to 0.08 ??g/L in groundwater samples.

Influences of chia flour and the concentration of total solids on the characteristics of ‘dulce de leche’ from goat milk

Directory of Open Access Journals (Sweden)

Marcia Alves CHAVES

2018-03-01

Full Text Available Abstract A factorial categorical design totalling six treatments was applied to investigate the influence of the substitution of corn starch with whole and partially defatted chia flour under the technical characteristics (centesimal composition, instrumental analyses, and sensory evaluation and nutritional disorders (composition of fatty acids and index of the nutritional quality of the lipid fraction of ‘dulce de leche’ concentrated to 72 and 78 °B. The treatments with chia flour concentrated to 72 °B showed higher moisture content and lower compression force, and when the concentration range increased to 78 °B, the levels of total lipids amounted up to 1.40 times when compared to treatment with corn starch. The polyunsaturated fatty acids, particularly omega-3 and omega-6 levels, were higher in treatments with chia flour on both tracks of concentration, allowing a reduction in the atherogenic index and thrombogenic index effects and the n-6/n-3 ratio. The treatments of ‘dulce de leche’ with a lower concentration of soluble solids obtained greater acceptance and consumer purchase intention. The application of whole chia flour in small proportions and in the concentration of 72 °B was the most appropriate under the studied conditions, showing improvement in the nutritional quality and with good technical aspects of candy made with goat milk.

Multiplexed Colorimetric Solid-Phase Extraction

Science.gov (United States)

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

Solid lipid nanoparticles mediate non-viral delivery of plasmid DNA to dendritic cells

Science.gov (United States)

Penumarthi, Alekhya; Parashar, Deepti; Abraham, Amanda N.; Dekiwadia, Chaitali; Macreadie, Ian; Shukla, Ravi; Smooker, Peter M.

2017-06-01

There is an increasing demand for novel DNA vaccine delivery systems, mainly for the non-viral type as they are considered relatively safe. Therefore, solid lipid nanoparticles (SLNs) were investigated for their suitability as a non-viral DNA vaccine delivery system. SLNs were synthesised by a modified solvent-emulsification method in order to study their potential to conjugate with plasmid DNA and deliver them in vitro to dendritic cells using eGFP as the reporter plasmid. The DNA-SLN complexes were characterised by electron microscopy, gel retardation assays and dynamic light scattering. The cytotoxicity assay data supported their biocompatibility and was used to estimate safe threshold concentration resulting in high transfection rate. The transfection efficiency of these complexes in a dendritic cell line was shown to increase significantly compared to plasmid alone, and was comparable to that mediated by lipofectamine. Transmission electron microscopy studies delineated the pathway of cellular uptake. Endosomal escape was observed supporting the mechanism of transfection.

Microplastic Effect Thresholds for Freshwater Benthic Macroinvertebrates

Science.gov (United States)

2018-01-01

Now that microplastics have been detected in lakes, rivers, and estuaries all over the globe, evaluating their effects on biota has become an urgent research priority. This is the first study that aims at determining the effect thresholds for a battery of six freshwater benthic macroinvertebrates with different species traits, using a wide range of microplastic concentrations. Standardized 28 days single species bioassays were performed under environmentally relevant exposure conditions using polystyrene microplastics (20–500 μm) mixed with sediment at concentrations ranging from 0 to 40% sediment dry weight (dw). Microplastics caused no effects on the survival of Gammarus pulex, Hyalella azteca, Asellus aquaticus, Sphaerium corneum, and Tubifex spp. and no effects were found on the reproduction of Lumbriculus variegatus. No significant differences in growth were found for H. azteca, A. aquaticus, S. corneum, L. variegatus, and Tubifex spp. However, G. pulex showed a significant reduction in growth (EC10 = 1.07% sediment dw) and microplastic uptake was proportional with microplastic concentrations in sediment. These results indicate that although the risks of environmentally realistic concentrations of microplastics may be low, they still may affect the biodiversity and the functioning of aquatic communities which after all also depend on the sensitive species. PMID:29337537

Characterization of the Factors that Influence Sinapine Concentration in Rapeseed Meal during Fermentation

Science.gov (United States)

Niu, Yanxing; Jiang, Mulan; Guo, Mian; Wan, Chuyun; Hu, Shuangxi; Jin, Hu; Huang, Fenghong

2015-01-01

We analyzed and compared the difference in sinapine concentration in rapeseed meal between the filamentous fungus, Trametes sp 48424, and the yeast, Saccharomyces cerevisiae, in both liquid and solid-state fermentation. During liquid and solid-state fermentation by Trametes sp 48424, the sinapine concentration decreased significantly. In contrast, the liquid and solid-state fermentation process by Saccharomyces cerevisiae just slightly decreased the sinapine concentration (P ≤ 0.05). After the solid-state fermented samples were dried, the concentration of sinapine in rapeseed meal decreased significantly in Saccharomyces cerevisiae. Based on the measurement of laccase activity, we observed that laccase induced the decrease in the concentration of sinapine during fermentation with Trametes sp 48424. In order to eliminate the influence of microorganisms and the metabolites produced during fermentation, high moisture rapeseed meal and the original rapeseed meal were dried at 90°C and 105°C, respectively. During drying, the concentration of sinapine in high moisture rapeseed meal decreased rapidly and we obtained a high correlation coefficient between the concentration of sinapine and loss of moisture. Our results suggest that drying and enzymes, especially laccase that is produced during the solid-state fermentation process, may be the main factors that affect the concentration of sinapine in rapeseed meal. PMID:25606856

Turbidity and total suspended solid concentration dynamics in streamflow from California oak woodland watersheds

Science.gov (United States)

David J. Lewis; Kenneth W. Tate; Randy A. Dahlgren; Jacob Newell

2002-01-01

Resource agencies, private landowners, and citizen monitoring programs utilize turbidity (water clarity) measurements as a water quality indicator for total suspended solids (TSS – mass of solids per unit volume) and other constituents in streams and rivers. The dynamics and relationships between turbidity and TSS are functions of watershed-specific factors and...

Small-threshold behaviour of two-loop self-energy diagrams: two-particle thresholds

International Nuclear Information System (INIS)

Berends, F.A.; Davydychev, A.I.; Moskovskij Gosudarstvennyj Univ., Moscow; Smirnov, V.A.; Moskovskij Gosudarstvennyj Univ., Moscow

1996-01-01

The behaviour of two-loop two-point diagrams at non-zero thresholds corresponding to two-particle cuts is analyzed. The masses involved in a cut and the external momentum are assumed to be small as compared to some of the other masses of the diagram. By employing general formulae of asymptotic expansions of Feynman diagrams in momenta and masses, we construct an algorithm to derive analytic approximations to the diagrams. In such a way, we calculate several first coefficients of the expansion. Since no conditions on relative values of the small masses and the external momentum are imposed, the threshold irregularities are described analytically. Numerical examples, using diagrams occurring in the standard model, illustrate the convergence of the expansion below the first large threshold. (orig.)

An integrated automatic system to evaluate U and Th dynamic lixiviation from solid matrices, and to extract/pre-concentrate leached analytes previous ICP-MS detection.

Science.gov (United States)

Ceballos, Melisa Rodas; García-Tenorio, Rafael; Estela, José Manuel; Cerdà, Víctor; Ferrer, Laura

2017-12-01

Leached fractions of U and Th from different environmental solid matrices were evaluated by an automatic system enabling the on-line lixiviation and extraction/pre-concentration of these two elements previous ICP-MS detection. UTEVA resin was used as selective extraction material. Ten leached fraction, using artificial rainwater (pH 5.4) as leaching agent, and a residual fraction were analyzed for each sample, allowing the study of behavior of U and Th in dynamic lixiviation conditions. Multivariate techniques have been employed for the efficient optimization of the independent variables that affect the lixiviation process. The system reached LODs of 0.1 and 0.7ngkg -1 of U and Th, respectively. The method was satisfactorily validated for three solid matrices, by the analysis of a soil reference material (IAEA-375), a certified sediment reference material (BCR- 320R) and a phosphogypsum reference material (MatControl CSN-CIEMAT 2008). Besides, environmental samples were analyzed, showing a similar behavior, i.e. the content of radionuclides decreases with the successive extractions. In all cases, the accumulative leached fraction of U and Th for different solid matrices studied (soil, sediment and phosphogypsum) were extremely low, up to 0.05% and 0.005% of U and Th, respectively. However, a great variability was observed in terms of mass concentration released, e.g. between 44 and 13,967ngUkg -1 . Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of waste solid on nuclide dispersal

International Nuclear Information System (INIS)

Seitz, M.G.; Steindler, M.J.

1981-01-01

The method most often considered for permanent disposal of radioactive waste is to incorporate the waste into a solid, which is then placed in a geologic formation. The solid is made of waste and nonradioactive additives, with the formulation selected to produce a durable solid that will minimize the potential for dispersal of the radionuclides. Leach rates of radionuclides incorporated in the solid waste indicate the quantity of radioactivity available for dispersal at any time; but leach rates of stable constituents can be just as important to radionuclide dispersal by groundwater. The constituents of the solid will perturb the chemical character of the groundwater and, thereby, profoundly affect the interaction of radionuclides with the geologic medium. An explicit example of how the solid waste can affect radionuclide dispersal is illustrated by the results of experiments that measure cesium adsorption in the presence of rubidium. The experiments were performed with granulated oolitic limestone that absorbed cesium from groundwater solutions to which various concentrations of stable rubidium chloride had been added. The results are expressed as partition coefficients. Large coefficients indicate strong adsorption by the rock and, hence, slow migration. The partition coefficient for cesium decreases as the rubidium concentration in solution is increased. Because the coeficient for cesium depends on the amount of rubidium in solution, it will depend on the leach rate of rubidium from the solid. Rubidium has no radionuclides of concern for long-term isolation of nuclear waste, so its leach rate from a waste solid is rarely ever reported

An inexpensive optical sensor system for monitoring total suspended solids in water

International Nuclear Information System (INIS)

Sami Gumaan Daraigan; Mohd Zubir Matjafri; Khiruddin Abdullah; Azlan Abdul Aziz; Abdul Aziz Tajuddin; Mohd Firdaus Othman

2005-01-01

The objectives of this work are to design and develop an optical transsmissometer sensor for measuring total suspended solids TSS concentrations in water samples. The proposed optical sensor has the advantages of being relatively inexpensive, and easy to make and operate. An optical algorithm has been developed and used for the measurement of total suspended solids concentrations. The developed optical sensor components include light emitting diodes LEDs that are used for measuring transmitted light. The concentrations of total suspended solids TSS are determined from transmitted light through the water samples. The transmitted light is measured in terms of the output voltage of the photodetector of the sensor system. The readings are measured using a digital multimeter. The results indicate that the level of the photocurrent is linearly proportional to the total suspended solids concentration. The proposed algorithm produces a high correlation coefficient and low root mean square error. (Author)

Ignition criterion for heterogeneous energetic materials based on hotspot size-temperature threshold

Science.gov (United States)

Barua, A.; Kim, S.; Horie, Y.; Zhou, M.

2013-02-01

A criterion for the ignition of granular explosives (GXs) and polymer-bonded explosives (PBXs) under shock and non-shock loading is developed. The formulation is based on integration of a quantification of the distributions of the sizes and locations of hotspots in loading events using a cohesive finite element method (CFEM) developed recently and the characterization by Tarver et al. [C. M. Tarver et al., "Critical conditions for impact- and shock-induced hot spots in solid explosives," J. Phys. Chem. 100, 5794-5799 (1996)] of the critical size-temperature threshold of hotspots required for chemical ignition of solid explosives. The criterion, along with the CFEM capability to quantify the thermal-mechanical behavior of GXs and PBXs, allows the critical impact velocity for ignition, time to ignition, and critical input energy at ignition to be determined as functions of material composition, microstructure, and loading conditions. The applicability of the relation between the critical input energy (E) and impact velocity of James [H. R. James, "An extension to the critical energy criterion used to predict shock initiation thresholds," Propellants, Explos., Pyrotech. 21, 8-13 (1996)] for shock loading is examined, leading to a modified interpretation, which is sensitive to microstructure and loading condition. As an application, numerical studies are undertaken to evaluate the ignition threshold of granular high melting point eXplosive, octahydro-1,3,5,7-tetranitro-1,2,3,5-tetrazocine (HMX) and HMX/Estane PBX under loading with impact velocities up to 350 ms-1 and strain rates up to 105 s-1. Results show that, for the GX, the time to criticality (tc) is strongly influenced by initial porosity, but is insensitive to grain size. Analyses also lead to a quantification of the differences between the responses of the GXs and PBXs in terms of critical impact velocity for ignition, time to ignition, and critical input energy at ignition. Since the framework permits

Concentration of pineapple juice by reverse osmosis: physicochemical characteristics and consumer acceptance

Directory of Open Access Journals (Sweden)

Daniel Simões Couto

2011-12-01

Full Text Available Reverse osmosis has been used for the concentration of fruit juices with promising considering the quality of the obtained products. The objective of this study was to concentrate single strength pineapple juice by reverse osmosis. The concentration was carried out with polyamide composite membranes in a 0.65 m² plate and frame module at 60 bar transmembrane pressure at 20 °C. The permeate flux was 17 L.hm-2. The total soluble solid content of the juice increased from 11 to 31 °Brix corresponding to a Volumetric Concentration Factor (VCF of 2.9. The concentration of soluble solids, total solids, and total acidity increased proportionally to FCV. The concentrated juice and three commercial concentrated pineapple juices were evaluated regarding preference and purchase intention by 79 pineapple juice consumers. The concentrated juice by reverse osmosis was the preferred among consumers. It can be concluded that this process may be considered an alternative to the pre-concentration of fruit juices.

Edible fat structures at high solid fat concentrations: Evidence for the existence of oil-filled nanospaces

Science.gov (United States)

Peyronel, Fernanda; Quinn, Bonnie; Marangoni, Alejandro G.; Pink, David A.

2015-01-01

We have characterized the surfaces of grain boundaries in edible oils with high solid fat content by combining ultra-small angle x-ray scattering (USAXS) with theoretical modelling and computer simulation. Our results will lead to understand the solid structures formed at the time of manufacturing fats like confectionery fats as well as pave the way for the engineering of innovative fat products. Edible fats are complex semi-solid materials where a solid structure entraps liquid oil. It was not until USAXS combined with modelling was used that the nano- to meso-structures for systems with less than 20% solids were understood. The interpretation of those results utilized models of crystalline nanoplatelets represented by rigid close-packed flat aggregates made of spheres and was allowed to aggregate using the Metropolis Monte Carlo technique. Here, we report on systems containing between 50% and 90% solids. We modelled the solid phase as being formed from seeds onto which solids condensed thereby giving rise to oil-filled nanospaces. The models predicted that the system (a) exhibits structures with fractal dimensions approximately 2, (b) a broad peak somewhat masking that slope, and (c) for smaller values of q, indications that the structures with fractal dimension approximately 2 are uniformly distributed in space. The interpretation of the experimental data was completely driven by these results. The computer simulation predictions were used in conjunction with the USAXS observations to conclude that the systems studied scattered from oil-cavities with sizes between ˜800 and ˜16 000 Å and possessed rough 2-dimensional walls.

Hyper-arousal decreases human visual thresholds.

Directory of Open Access Journals (Sweden)

Adam J Woods

Full Text Available Arousal has long been known to influence behavior and serves as an underlying component of cognition and consciousness. However, the consequences of hyper-arousal for visual perception remain unclear. The present study evaluates the impact of hyper-arousal on two aspects of visual sensitivity: visual stereoacuity and contrast thresholds. Sixty-eight participants participated in two experiments. Thirty-four participants were randomly divided into two groups in each experiment: Arousal Stimulation or Sham Control. The Arousal Stimulation group underwent a 50-second cold pressor stimulation (immersing the foot in 0-2° C water, a technique known to increase arousal. In contrast, the Sham Control group immersed their foot in room temperature water. Stereoacuity thresholds (Experiment 1 and contrast thresholds (Experiment 2 were measured before and after stimulation. The Arousal Stimulation groups demonstrated significantly lower stereoacuity and contrast thresholds following cold pressor stimulation, whereas the Sham Control groups showed no difference in thresholds. These results provide the first evidence that hyper-arousal from sensory stimulation can lower visual thresholds. Hyper-arousal's ability to decrease visual thresholds has important implications for survival, sports, and everyday life.

Evolution of ion damage at 773K in Ni- containing concentrated solid-solution alloys

Science.gov (United States)

Shi, Shi; He, Mo-Rigen; Jin, Ke; Bei, Hongbin; Robertson, Ian M.

2018-04-01

Quantitative analysis of the impact of the compositional complexity in a series of Ni-containing concentrated solid-solution alloys, Ni, NiCo, NiFe, NiCoCr, NiCoFeCr, NiCoFeCrMn and NiCoFeCrPd, on the evolution of defects produced by 1 MeV Kr ion irradiation at 773 K is reported. The dynamics of the evolution of the damage structure during irradiation to a dose of 2 displacements per atom were observed directly by performing the ion irradiations in electron transparent foils in a transmission electron microscope coupled to an ion accelerator. The defect evolution was assessed through measurement of the defect density, defect size and fraction of perfect and Frank loops. These three parameters were dependent on the alloying element as well as the number of elements. The population of loops was sensitive to the ion dose and alloy composition as faulted Frank loops were observed to unfault to perfect loops with increasing ion dose. These dependences are explained in terms of the influence of each element on the lifetime of the displacement cascade as well as on defect formation and migration energies.

Threshold pressure for mechanoluminescence of macrocrystals, microcrystals and nanocrystals of doped zinc sulphide

Energy Technology Data Exchange (ETDEWEB)

Chandra, B.P. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur 492010, C.G. (India); Chandra, V.K. [Department of Electrical and Electronics Engineering, Chhatrapati Shivaji Institute of Technology, Shivaji Nagar, Kolihapuri, Durg 491001, C.G. (India); Jha, Piyush, E-mail: piyushjha22@rediffmail.com [Department of Applied Physics, Raipur Institute of Technology, Chhatauna, Mandir Hasuad, Raipur 492101, C.G. (India); Sonwane, V.D. [School of Studies in Physics and Astrophysics, Pt. Ravishankar Shukla University, Raipur 492010, C.G. (India)

2016-06-15

The threshold pressure for elastico-mechanoluminescence (EML) of ZnS:Mn macrocrystals is 20 MPa, and ZnS:Cu,Al macrocrystals do not show ML during elastic deformation. However, the threshold pressure for EML of ZnS:Mn and ZnS:Cu,Cl microcrystals and nanocrystals is nearly 1 MPa. Thus, it seems that high concentration of defects in microcrystalline and nanocrystalline ZnS:Mn and ZnS:Cu,Cl produces disorder and distortion in lattice and changes the local crystal-structure near impurities, and consequently, the enhanced piezoelectric constant of local region produces EML for low value of applied pressure. The threshold pressure for the ML of ZnS:Mn and ZnS:Cu,Al single macrocrystals is higher because such crystals possess comparatively less number of defects near the impurities where the phase-transition is not possible and their ML is caused for high value of stress because the bulk piezoelectric constant is less. Thus, size-dependent threshold pressure for ML supports the origin of EML from piezoelectricity in local region of the crystals. The finding of present investigation may be useful in tailoring phosphors emitting intense EML of different colours.

Threshold pressure for mechanoluminescence of macrocrystals, microcrystals and nanocrystals of doped zinc sulphide

International Nuclear Information System (INIS)

Chandra, B.P.; Chandra, V.K.; Jha, Piyush; Sonwane, V.D.

2016-01-01

The threshold pressure for elastico-mechanoluminescence (EML) of ZnS:Mn macrocrystals is 20 MPa, and ZnS:Cu,Al macrocrystals do not show ML during elastic deformation. However, the threshold pressure for EML of ZnS:Mn and ZnS:Cu,Cl microcrystals and nanocrystals is nearly 1 MPa. Thus, it seems that high concentration of defects in microcrystalline and nanocrystalline ZnS:Mn and ZnS:Cu,Cl produces disorder and distortion in lattice and changes the local crystal-structure near impurities, and consequently, the enhanced piezoelectric constant of local region produces EML for low value of applied pressure. The threshold pressure for the ML of ZnS:Mn and ZnS:Cu,Al single macrocrystals is higher because such crystals possess comparatively less number of defects near the impurities where the phase-transition is not possible and their ML is caused for high value of stress because the bulk piezoelectric constant is less. Thus, size-dependent threshold pressure for ML supports the origin of EML from piezoelectricity in local region of the crystals. The finding of present investigation may be useful in tailoring phosphors emitting intense EML of different colours.

A numerical study of threshold states

International Nuclear Information System (INIS)

Ata, M.S.; Grama, C.; Grama, N.; Hategan, C.

1979-01-01

There are some experimental evidences of charged particle threshold states. On the statistical background of levels, some simple structures were observed in excitation spectrum. They occur near the coulombian threshold and have a large reduced width for the decay in the threshold channel. These states were identified as charged cluster threshold states. Such threshold states were observed in sup(15,16,17,18)O, sup(18,19)F, sup(19,20)Ne, sup(24)Mg, sup(32)S. The types of clusters involved were d, t, 3 He, α and even 12 C. They were observed in heavy-ions transfer reactions in the residual nucleus as strong excited levels. The charged particle threshold states occur as simple structures at high excitation energy. They could be interesting both from nuclear structure as well as nuclear reaction mechanism point of view. They could be excited as simple structures both in compound and residual nucleus. (author)

Operating modes of electrochemical H-concentration probes for tritium sensors

International Nuclear Information System (INIS)

Juhera, E.; Colominas, S.; Abellà, J.

2015-01-01

Highlights: • Synthesis and chemical characterization of Sr(Ce_0_._9–Zr_0_._1)_0_._9_5Yb_0_._0_5O_3_−_α proton conductor ceramic. • Evaluation of the sensor performance at different hydrogen concentrations. • Two different operating modes of the sensors: amperometric and potentiometric. • In amperometric mode sensor sensitivity can be tuned by changing the applied voltage. - Abstract: Potentiometric hydrogen sensors using different solid-state electrolytes have been designed and tested at the Electrochemical Methods Lab at Institut Quimic de Sarria (IQS). The most promising element (Sr(Ce_0_._9–Zr_0_._1)_0_._9_5Yb_0_._0_5O_3_−_α) has been selected for this work in order to evaluate the sensor performance at different hydrogen concentrations in two different operating modes: amperometric and potentiometric. In addition, the sensor response has been evaluated at different working temperatures (500, 575 and 650 °C). The experiments performed proved that when the sensor was used in a potentiometric mode, there is a threshold hydrogen concentration that the sensor can detect depending on the working conditions; 15 mbar at 575 °C and 10 mbar 650 °C. At 500 °C the minimum working temperature of this ceramic has not been achieved, so large deviations between experimental data and theoretical calculations has been obtained. When the sensor was used in an amperometric mode the obtained currents increased as a function of the applied voltage. At a fixed potential, the higher the temperature the higher the current was. So the sensor sensitivity can be tuned by changing the applied voltage at a fixed temperature and hydrogen concentration.

Enzymatic lignocellulose hydrolysis: Improved cellulase productivity by insoluble solids recycling

DEFF Research Database (Denmark)

Weiss, Noah Daniel; Börjesson, Johan; Pedersen, Lars Saaby

2013-01-01

To take advantage of this effect, the amount of solids recycled should be maximized, based on a given processes ability to deal with higher solids concentrations and volumes. Recycling of enzymes by recycling the insoluble solids fraction was thus shown to be an effective method to decrease enzym...

Effects of solid feed level and roughage-to-concentrate ratio on ruminal drinking and passage kinetics of milk replacer, concentrates, and roughage in veal calves.

Science.gov (United States)

Berends, H; van den Borne, J J G C; Stockhofe-Zurwieden, N; Gilbert, M S; Zandstra, T; Pellikaan, W F; van Reenen, C G; Bokkers, E A M; Gerrits, W J J

2015-08-01

Effects of solid feed (SF) level and roughage-to-concentrate (R:C) ratio on ruminal drinking and passage kinetics of milk replacer, concentrate, and roughage were studied in veal calves. In total, 80 male Holstein-Friesian calves (45±0.2kg of body weight) were divided over 16 pens (5 calves per pen). Pens were randomly assigned to either a low (LSF) or a high (HSF) SF level and to 1 of 2 R:C ratios: 20:80 or 50:50 on a dry matter (DM) basis. Roughage was composed of 50% corn silage and 50% chopped wheat straw on a DM basis. At 27 wk of age, measurements were conducted in 32 calves. During the measurement period, SF intake was 1.2kg of DM/d for LSF and 3.0kg of DM/d for HSF, and milk replacer intake averaged 2.3kg of DM/d for LSF and 1.3kg of DM/d for HSF. To estimate passage kinetics of milk replacer, concentrate, and straw, indigestible markers (CoEDTA, hexatriacontane C36, Cr-neutral detergent fiber) were supplied with the feed as a single dose 4, 24, and 48h before assessment of their quantitative recovery in the rumen, abomasum, small intestine, and large intestine. Rumen Co recovery averaged 20% of the last milk replacer meal. Recoveries of Co remained largely unaffected by SF level and R:C ratio. The R:C ratio did not affect rumen recovery of C36 or Cr. Rumen fractional passage rate of concentrate was estimated from recovery of C36 in the rumen and increased from 3.3%/h for LSF to 4.9%/h for HSF. Rumen fractional passage rate of straw was estimated from Cr recovery in the rumen and increased from 1.3%/h for LSF to 1.7%/h for HSF. An increase in SF level was accompanied by an increase in fresh and dry rumen contents. In HSF calves, pH decreased and VFA concentrations increased with increasing concentrate proportion, indicating increased fermentation. The ratio between Cr and C36 was similar in the small and large intestine, indicating that passage of concentrate and straw is mainly determined by rumen and abomasum emptying. In conclusion, increasing SF level

Seven benzimidazole pesticides combined at sub-threshold levels induce micronuclei in vitro

Science.gov (United States)

Ermler, Sibylle; Scholze, Martin; Kortenkamp, Andreas

2013-01-01

Benzimidazoles act by disrupting microtubule polymerisation and are capable of inducing the formation of micronuclei. Considering the similarities in their mechanisms of action (inhibition of microtubule assembly by binding to the colchicine-binding site on tubulin monomers), combination effects according to the principles of concentration addition might occur. If so, it is to be expected that several benzimidazoles contribute to micronucleus formation even when each single one is present at or below threshold levels. This would have profound implications for risk assessment, but the idea has never been tested rigorously. To fill this gap, we analysed micronucleus frequencies for seven benzimidazoles, including the fungicide benomyl, its metabolite carbendazim, the anthelmintics albendazole, albendazole oxide, flubendazole, mebendazole and oxibendazole. Thiabendazole was also tested but was inactive. We used the cytochalasin-blocked micronucleus assay with CHO-K1 cells according to OECD guidelines, and employed an automated micronucleus scoring system based on image analysis to establish quantitative concentration–response relationships for the seven active benzimidazoles. Based on this information, we predicted additive combination effects for a mixture of the seven benzimidazoles by using the concepts of concentration addition and independent action. The observed effects of the mixture agreed very well with those predicted by concentration addition. Independent action underestimated the observed combined effects by a large margin. With a mixture that combined all benzimidazoles at their estimated threshold concentrations for micronucleus induction, micronucleus frequencies of ~15.5% were observed, correctly anticipated by concentration addition. On the basis of independent action, this mixture was expected to produce no effects. Our data provide convincing evidence that concentration addition is applicable to combinations of benzimidazoles that form micronuclei

Conceptions of nuclear threshold status

International Nuclear Information System (INIS)

Quester, G.H.

1991-01-01

This paper reviews some alternative definitions of nuclear threshold status. Each of them is important, and major analytical confusions would result if one sense of the term is mistaken for another. The motives for nations entering into such threshold status are a blend of civilian and military gains, and of national interests versus parochial or bureaucratic interests. A portion of the rationale for threshold status emerges inevitably from the pursuit of economic goals, and another portion is made more attraction by the derives of the domestic political process. Yet the impact on international security cannot be dismissed, especially where conflicts among the states remain real. Among the military or national security motives are basic deterrence, psychological warfare, war-fighting and, more generally, national prestige. In the end, as the threshold phenomenon is assayed for lessons concerning the role of nuclear weapons more generally in international relations and security, one might conclude that threshold status and outright proliferation coverage to a degree in the motives for all of the states involved and in the advantages attained. As this paper has illustrated, nuclear threshold status is more subtle and more ambiguous than outright proliferation, and it takes considerable time to sort out the complexities. Yet the world has now had a substantial amount of time to deal with this ambiguous status, and this may tempt more states to exploit it

Simulated effects of surface coal mining and agriculture on dissolved solids in the Redwater River, east-central Montana

Science.gov (United States)

Ferreira, R.F.; Lambing, J.H.

1985-01-01

Dissolved solids concentrations in five reaches of the Redwater River in east-central Montana were simulated to evaluate the effects of surface coal mining and agriculture. A mass-balance model of streamflow and dissolved solids load developed for the Tongue River in southeastern Montana was modified and applied to the Redwater River. Mined acreages, dissolved solids concentrations in mined spoils, and irrigated acreage can be varied in the model to study relative changes in the dissolved solids concentration in consecutive reaches of the river. Because of extreme variability and a limited amount of data, the model was not consecutively validated. Simulated mean and median monthly mean streamflows and consistently larger than those calculated from streamflow records. Simulated mean and median monthly mean dissolved solids loads also are consistently larger than regression-derived values. These discrepancies probably result from extremely variable streamflow, overestimates of streamflow from ungaged tributaries, and weak correlations between streamflow and dissolved solids concentrations. The largest increases in simulated dissolved solids concentrations from mining and agriculture occur from September through January because of smaller streamflows and dissolved solids loads. Different combinations of agriculture and mining under mean flow conditions resulted in cumulative percentage increases of dissolved solids concentrations of less than 5% for mining and less than 2% for agriculture. (USGS)

Specific Conductance and Dissolved-Solids Characteristics for the Green River and Muddy Creek, Wyoming, Water Years 1999-2008

Science.gov (United States)

Clark, Melanie L.; Davidson, Seth L.

2009-01-01

Southwestern Wyoming is an area of diverse scenery, wildlife, and natural resources that is actively undergoing energy development. The U.S. Department of the Interior's Wyoming Landscape Conservation Initiative is a long-term science-based effort to assess and enhance aquatic and terrestrial habitats at a landscape scale, while facilitating responsible energy development through local collaboration and partnerships. Water-quality monitoring has been conducted by the U.S. Geological Survey on the Green River near Green River, Wyoming, and Muddy Creek near Baggs, Wyoming. This monitoring, which is being conducted in cooperation with State and other Federal agencies and as part of the Wyoming Landscape Conservation Initiative, is in response to concerns about potentially increased dissolved solids in the Colorado River Basin as a result of energy development. Because of the need to provide real-time dissolved-solids concentrations for the Green River and Muddy Creek on the World Wide Web, the U.S. Geological Survey developed regression equations to estimate dissolved-solids concentrations on the basis of continuous specific conductance using relations between measured specific conductance and dissolved-solids concentrations. Specific conductance and dissolved-solids concentrations were less varied and generally lower for the Green River than for Muddy Creek. The median dissolved-solids concentration for the site on the Green River was 318 milligrams per liter, and the median concentration for the site on Muddy Creek was 943 milligrams per liter. Dissolved-solids concentrations ranged from 187 to 594 milligrams per liter in samples collected from the Green River during water years 1999-2008. Dissolved-solids concentrations ranged from 293 to 2,485 milligrams per liter in samples collected from Muddy Creek during water years 2006-08. The differences in dissolved-solids concentrations in samples collected from the Green River compared to samples collected from Muddy

Solid-phase spectrophotometry

International Nuclear Information System (INIS)

Brykina, G.D.; Marchenko, D.Yu.; Shpigun, O.A.

1995-01-01

Solid-phase spectrophotometry (SPS), which is based on the direct measurement of light absorption of an ion exchanger containing a substance of interest, was reviewed. Since 1976, it has been known that aborbance of an ion exchanger is directly proportional to the concentration of a particular ion in solution. A similar dependence can also be followed for other sorbents, as well as for foams, membranes, films, etc., which do not exhibit ion exchange properties. One can use absorption, diffuse reflection, and luminescence spectra parameters as an analytical signal. Thus, SPS of ion exchangers is among the analytical techniques that combine the sorption concentration and surface determination of the substance of interest. This review summarizes the advancements in SPS over the last six years and demonstrates the prospects for its development. Special attention is paid to experimental methods for measuring solid-phase absorption and to the basic procedures of sample preparation, including new ones. These two facets are of great importance for obtaining precise results and extending the capabilities of SPS

Bleaching threshold of cationic radicals of alkanes and capture energy of the positive hole of these ions in irradiated solid matrix

International Nuclear Information System (INIS)

Van den Bosch, A.; Strobbe, M.; Ceulemans, J.

1984-01-01

Gamma irradiated Cl 3 CCF 3 shows an absorption band at about 360 nm, and another band, at 600 nm. The band at 600 nm disappears completely by irradiation with light of lambda>610 nm. Cl 3 CCF 3 containing 1% of decane irradiated at 77 K presents the some phenomena. Selective bleaching by photons of increasing energy allows the determination of the threshold for bleaching of cationic radicals of decane trapped in Cl 3 CCF 3 . Distinction between photoinduced charge transfer and photodissociation is obtained by addition of tetramethyl-p-phenylenediame. Showing that bleaching threshold corresponds to the capture energy of the positive hole on decane cationic radical [fr

Threshold Concepts in Finance: Student Perspectives

Science.gov (United States)

Hoadley, Susan; Kyng, Tim; Tickle, Leonie; Wood, Leigh N.

2015-01-01

Finance threshold concepts are the essential conceptual knowledge that underpin well-developed financial capabilities and are central to the mastery of finance. In this paper we investigate threshold concepts in finance from the point of view of students, by establishing the extent to which students are aware of threshold concepts identified by…

Thresholding magnetic resonance images of human brain

Institute of Scientific and Technical Information of China (English)

Qing-mao HU; Wieslaw L NOWINSKI

2005-01-01

In this paper, methods are proposed and validated to determine low and high thresholds to segment out gray matter and white matter for MR images of different pulse sequences of human brain. First, a two-dimensional reference image is determined to represent the intensity characteristics of the original three-dimensional data. Then a region of interest of the reference image is determined where brain tissues are present. The non-supervised fuzzy c-means clustering is employed to determine: the threshold for obtaining head mask, the low threshold for T2-weighted and PD-weighted images, and the high threshold for T1-weighted, SPGR and FLAIR images. Supervised range-constrained thresholding is employed to determine the low threshold for T1-weighted, SPGR and FLAIR images. Thresholding based on pairs of boundary pixels is proposed to determine the high threshold for T2- and PD-weighted images. Quantification against public data sets with various noise and inhomogeneity levels shows that the proposed methods can yield segmentation robust to noise and intensity inhomogeneity. Qualitatively the proposed methods work well with real clinical data.

Near threshold fatigue testing

Science.gov (United States)

Freeman, D. C.; Strum, M. J.

1993-01-01

Measurement of the near-threshold fatigue crack growth rate (FCGR) behavior provides a basis for the design and evaluation of components subjected to high cycle fatigue. Typically, the near-threshold fatigue regime describes crack growth rates below approximately 10(exp -5) mm/cycle (4 x 10(exp -7) inch/cycle). One such evaluation was recently performed for the binary alloy U-6Nb. The procedures developed for this evaluation are described in detail to provide a general test method for near-threshold FCGR testing. In particular, techniques for high-resolution measurements of crack length performed in-situ through a direct current, potential drop (DCPD) apparatus, and a method which eliminates crack closure effects through the use of loading cycles with constant maximum stress intensity are described.

Linear and nonlinear optical absorption coefficients in GaAs/Ga{sub 1-x}Al{sub x}As concentric double quantum rings: Effects of hydrostatic pressure and aluminum concentration

Energy Technology Data Exchange (ETDEWEB)

Baghramyan, H.M. [Department of Solid State Physics, Yerevan State University, Al. Manookian 1, 0025 Yerevan (Armenia); Barseghyan, M.G., E-mail: mbarsegh@ysu.am [Department of Solid State Physics, Yerevan State University, Al. Manookian 1, 0025 Yerevan (Armenia); Kirakosyan, A.A. [Department of Solid State Physics, Yerevan State University, Al. Manookian 1, 0025 Yerevan (Armenia); Restrepo, R.L. [Escuela de Ingenieria de Antioquia, AA 7516 Medellin (Colombia); Duque, C.A. [Instituto de Fisica, Universidad de Antioquia, AA 1226 Medellin (Colombia)

2013-02-15

The linear and nonlinear intra-band optical absorption coefficients in GaAs/Ga{sub 1-x}Al{sub x}As two-dimensional concentric double quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and aluminum concentration the energies of the ground (n=1,l=0) and the first excited state (n=2,l=1) have been found using the effective mass approximation and the transfer matrix formalism. The energies of these states and the corresponding threshold energy of the intra-band optical transitions are examined as a function of hydrostatic pressure and aluminum concentration for different sizes of the structure. We also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as functions of the incident photon energy for different values of hydrostatic pressure, aluminum concentration, sizes of the structure, and incident optical intensity. Its is found that the effects of the hydrostatic pressure and the aluminum concentration lead to a shifting of the resonant peaks of the intra-band optical spectrum. - Highlights: Black-Right-Pointing-Pointer Linear and nonlinear intra-band absorption in quantum rings. Black-Right-Pointing-Pointer Threshold energy strongly depends on the hydrostatic pressure. Black-Right-Pointing-Pointer Threshold energy strongly depends on the stoichiometry and sizes of structure. Black-Right-Pointing-Pointer Optical absorption is affected by the incident optical intensity.

Radiation-induced segregation on defect clusters in single-phase concentrated solid-solution alloys

International Nuclear Information System (INIS)

Lu, Chenyang; Yang, Taini; Jin, Ke; Gao, Ning; Xiu, Pengyuan; Zhang, Yanwen; Gao, Fei; Bei, Hongbin; Weber, William J.; Sun, Kai; Dong, Yan; Wang, Lumin

2017-01-01

A group of single-phase concentrated solid-solution alloys (SP-CSAs), including NiFe, NiCoFe, NiCoFeCr, as well as a high entropy alloy NiCoFeCrMn, was irradiated with 3 MeV Ni"2"+ ions at 773 K to a fluence of 5 × 10"1"6 ions/cm"2 for the study of radiation response with increasing compositional complexity. Advanced transmission electron microscopy (TEM) with electron energy loss spectroscopy (EELS) was used to characterize the dislocation loop distribution and radiation-induced segregation (RIS) on defect clusters in the SP-CSAs. The results show that a higher fraction of faulted loops exists in the more compositionally complex alloys, which indicate that increasing compositional complexity can extend the incubation period and delay loop growth. The RIS behaviors of each element in the SP-CSAs were observed as follows: Ni and Co tend to enrich, but Cr, Fe and Mn prefer to deplete near the defect clusters. RIS level can be significantly suppressed by increasing compositional complexity due to the sluggish atom diffusion. According to molecular static (MS) simulations, “disk” like segregations may form near the faulted dislocation loops in the SP-CSAs. Segregated elements tend to distribute around the whole faulted loop as a disk rather than only around the edge of the loop.

At-Risk-of-Poverty Threshold

Directory of Open Access Journals (Sweden)

Táňa Dvornáková

2012-06-01

Full Text Available European Statistics on Income and Living Conditions (EU-SILC is a survey on households’ living conditions. The main aim of the survey is to get long-term comparable data on social and economic situation of households. Data collected in the survey are used mainly in connection with the evaluation of income poverty and determinationof at-risk-of-poverty rate. This article deals with the calculation of the at risk-of-poverty threshold based on data from EU-SILC 2009. The main task is to compare two approaches to the computation of at riskof-poverty threshold. The first approach is based on the calculation of the threshold for each country separately,while the second one is based on the calculation of the threshold for all states together. The introduction summarizes common attributes in the calculation of the at-risk-of-poverty threshold, such as disposable household income, equivalised household income. Further, different approaches to both calculations are introduced andadvantages and disadvantages of these approaches are stated. Finally, the at-risk-of-poverty rate calculation is described and comparison of the at-risk-of-poverty rates based on these two different approaches is made.

In what root-zone N concentration does nitrate start to leach significantly? A reasonable answer from modeling Mediterranean field data and closed root-zone experiments

Science.gov (United States)

Kurtzman, D.; Kanner, B.; Levy, Y.; Shapira, R. H.; Bar-Tal, A.

2017-12-01

Closed-root-zone experiments (e.g. pots, lyzimeters) reveal in many cases a mineral-nitrogen (N) concentration from which the root-N-uptake efficiency reduces significantly and nitrate leaching below the root-zone increases dramatically. A les-direct way to reveal this threshold concentration in agricultural fields is to calibrate N-transport models of the unsaturated zone to nitrate data of the deep samples (under the root-zone) by fitting the threshold concentration of the nitrate-uptake function. Independent research efforts of these two types in light soils where nitrate problems in underlying aquifers are common reviled: 1) that the threshold exists for most crops (filed, vegetables and orchards); 2) nice agreement on the threshold value between the two very different research methodologies; and 3) the threshold lies within 20-50 mg-N/L. Focusing on being below the threshold is a relatively simple aim in the way to maintain intensive agriculture with limited effects on the nitrate concentration in the underlying water resource. Our experience show that in some crops this threshold coincides with the end-of-rise of the N-yield curve (e.g. corn); in this case, it is relatively easy to convince farmers to fertilize below threshold. In other crops, although significant N is lost to leaching the crop can still use higher N concentration to increase yield (e.g. potato).

Investigation on the inertial cavitation threshold and shell properties of commercialized ultrasound contrast agent microbubbles.

Science.gov (United States)

Guo, Xiasheng; Li, Qian; Zhang, Zhe; Zhang, Dong; Tu, Juan

2013-08-01

The inertial cavitation (IC) activity of ultrasound contrast agents (UCAs) plays an important role in the development and improvement of ultrasound diagnostic and therapeutic applications. However, various diagnostic and therapeutic applications have different requirements for IC characteristics. Here through IC dose quantifications based on passive cavitation detection, IC thresholds were measured for two commercialized UCAs, albumin-shelled KangRun(®) and lipid-shelled SonoVue(®) microbubbles, at varied UCA volume concentrations (viz., 0.125 and 0.25 vol. %) and acoustic pulse lengths (viz., 5, 10, 20, 50, and 100 cycles). Shell elastic and viscous coefficients of UCAs were estimated by fitting measured acoustic attenuation spectra with Sarkar's model. The influences of sonication condition (viz., acoustic pulse length) and UCA shell properties on IC threshold were discussed based on numerical simulations. Both experimental measurements and numerical simulations indicate that IC thresholds of UCAs decrease with increasing UCA volume concentration and acoustic pulse length. The shell interfacial tension and dilatational viscosity estimated for SonoVue (0.7 ± 0.11 N/m, 6.5 ± 1.01 × 10(-8) kg/s) are smaller than those of KangRun (1.05 ± 0.18 N/m, 1.66 ± 0.38 × 10(-7) kg/s); this might result in lower IC threshold for SonoVue. The current results will be helpful for selecting and utilizing commercialized UCAs for specific clinical applications, while minimizing undesired IC-induced bioeffects.

Summary of DOE threshold limits efforts

International Nuclear Information System (INIS)

Wickham, L.E.; Smith, C.F.; Cohen, J.J.

1987-01-01

The Department of Energy (DOE) has been developing the concept of threshold quantities for use in determining which waste materials may be disposed of as nonradioactive waste in DOE sanitary landfills. Waste above a threshold level could be managed as radioactive or mixed waste (if hazardous chemicals are present); waste below this level would be handled as sanitary waste. After extensive review of a draft threshold guidance document in 1985, a second draft threshold background document was produced in March 1986. The second draft included a preliminary cost-benefit analysis and quality assurance considerations. The review of the second draft has been completed. Final changes to be incorporated include an in-depth cost-benefit analysis of two example sites and recommendations of how to further pursue (i.e. employ) the concept of threshold quantities within the DOE. 3 references

Stiffening solids with liquid inclusions

Science.gov (United States)

Style, Robert W.; Boltyanskiy, Rostislav; Allen, Benjamin; Jensen, Katharine E.; Foote, Henry P.; Wettlaufer, John S.; Dufresne, Eric R.

2015-01-01

From bone and wood to concrete and carbon fibre, composites are ubiquitous natural and synthetic materials. Eshelby’s inclusion theory describes how macroscopic stress fields couple to isolated microscopic inclusions, allowing prediction of a composite’s bulk mechanical properties from a knowledge of its microstructure. It has been extended to describe a wide variety of phenomena from solid fracture to cell adhesion. Here, we show experimentally and theoretically that Eshelby’s theory breaks down for small liquid inclusions in a soft solid. In this limit, an isolated droplet’s deformation is strongly size-dependent, with the smallest droplets mimicking the behaviour of solid inclusions. Furthermore, in opposition to the predictions of conventional composite theory, we find that finite concentrations of small liquid inclusions enhance the stiffness of soft solids. A straightforward extension of Eshelby’s theory, accounting for the surface tension of the solid-liquid interface, explains our experimental observations. The counterintuitive stiffening of solids by fluid inclusions is expected whenever inclusion radii are smaller than an elastocapillary length, given by the ratio of the surface tension to Young’s modulus of the solid matrix. These results suggest that surface tension can be a simple and effective mechanism to cloak the far-field elastic signature of inclusions.

Chemical digestion of low level nuclear solid waste material

International Nuclear Information System (INIS)

Cooley, C.R.; Lerch, R.E.

1976-01-01

A chemical digestion for treatment of low level combustible nuclear solid waste material is provided and comprises reacting the solid waste material with concentrated sulfuric acid at a temperature within the range of 230 0 --300 0 C and simultaneously and/or thereafter contacting the reacting mixture with concentrated nitric acid or nitrogen dioxide. In a special embodiment spent ion exchange resins are converted by this chemical digestion to noncombustible gases and a low volume noncombustible residue. 6 claims, no drawings

Parton distributions with threshold resummation

CERN Document Server

Bonvini, Marco; Rojo, Juan; Rottoli, Luca; Ubiali, Maria; Ball, Richard D.; Bertone, Valerio; Carrazza, Stefano; Hartland, Nathan P.

2015-01-01

We construct a set of parton distribution functions (PDFs) in which fixed-order NLO and NNLO calculations are supplemented with soft-gluon (threshold) resummation up to NLL and NNLL accuracy respectively, suitable for use in conjunction with any QCD calculation in which threshold resummation is included at the level of partonic cross sections. These resummed PDF sets, based on the NNPDF3.0 analysis, are extracted from deep-inelastic scattering, Drell-Yan, and top quark pair production data, for which resummed calculations can be consistently used. We find that, close to threshold, the inclusion of resummed PDFs can partially compensate the enhancement in resummed matrix elements, leading to resummed hadronic cross-sections closer to the fixed-order calculation. On the other hand, far from threshold, resummed PDFs reduce to their fixed-order counterparts. Our results demonstrate the need for a consistent use of resummed PDFs in resummed calculations.

Effect of threshold quantization in opportunistic splitting algorithm

KAUST Repository

Nam, Haewoon

2011-12-01

This paper discusses algorithms to find the optimal threshold and also investigates the impact of threshold quantization on the scheduling outage performance of the opportunistic splitting scheduling algorithm. Since this algorithm aims at finding the user with the highest channel quality within the minimal number of mini-slots by adjusting the threshold every mini-slot, optimizing the threshold is of paramount importance. Hence, in this paper we first discuss how to compute the optimal threshold along with two tight approximations for the optimal threshold. Closed-form expressions are provided for those approximations for simple calculations. Then, we consider linear quantization of the threshold to take the limited number of bits for signaling messages in practical systems into consideration. Due to the limited granularity for the quantized threshold value, an irreducible scheduling outage floor is observed. The numerical results show that the two approximations offer lower scheduling outage probability floors compared to the conventional algorithm when the threshold is quantized. © 2006 IEEE.

Laser-induced nonsequential double ionization at and above the recollision-excitation-tunneling threshold

International Nuclear Information System (INIS)

Shaaran, T.; Figueira de Morisson Faria, C.; Nygren, M. T.

2010-01-01

We perform a rigorous, semianalytic study of the recollision excitation with subsequent tunneling ionization (RESI) mechanism in laser-induced nonsequential double ionization (NSDI), based on the strong-field approximation. We show that the shapes of the electron momentum distributions carry information about the bound state with which the first electron collides, the bound state to which the second electron is excited, and the type of electron-electron interaction. Furthermore, one may define a driving-field intensity threshold for the RESI physical mechanism. At the threshold, the kinetic energy of the first electron, upon return, is just sufficient to excite the second electron. We compute the distributions for helium and argon in the threshold and above-threshold intensity regimes. In the latter case, we relate our findings to existing experiments. The electron momentum distributions encountered are symmetric with respect to all quadrants of the plane spanned by the momentum components parallel to the laser-field polarization, instead of concentrating on only the second and fourth quadrants. The above-mentioned momentum constraints, together with the strong dependence of the distributions on the bound states involved, may be important for singling out the RESI mechanism in actual physical situations and using NSDI in ultrafast imaging.

Determination of fluorine in copper concentrate via high-resolution graphite furnace molecular absorption spectrometry and direct solid sample analysis - Comparison of three target molecules.

Science.gov (United States)

Cadorim, Heloisa R; de Gois, Jefferson S; Borges, Aline R; Vale, Maria Goreti R; Welz, Bernhard; Gleisner, Heike; Ott, Christina

2018-01-01

The chemical composition of complex inorganic materials, such as copper concentrate, may influence the economics of their further processing because most smelters, and particularly the producers of high-purity electrolyte copper, have strict limitations for the permissible concentration of impurities. These components might be harmful to the quality of the products, impair the production process and be hazardous to the environment. The goal of the present work is the development of a method for the determination of fluorine in copper concentrate using high-resolution graphite furnace molecular absorption spectrometry and direct solid sample analysis. The molecular absorption of the diatomic molecule CaF was measured at 606.440nm. The molecule CaF was generated by the addition of 200µg Ca as the molecule-forming reagent; the optimized pyrolysis and vaporization temperatures were 900°C and 2400°C, respectively. The characteristic mass and limit of detection were 0.5ng and 3ng, respectively. Calibration curves were established using aqueous standard solutions containing the major components Cu, Fe, S and the minor component Ag in optimized concentrations. The accuracy of the method was verified using certified reference materials. Fourteen copper concentrate samples from Chile and Australia were analyzed to confirm the applicability of the method to real samples; the concentration of fluorine ranged from 34 to 5676mgkg -1 . The samples were also analyzed independently at Analytik Jena by different operators, using the same equipment, but different target molecules, InF and GaF, and different operating conditions; but with a few exceptions, the results agreed quite well. The results obtained at Analytik Jena using the GaF molecule and our results obtained with CaF, with one exception, were also in agreement with the values informed by the supplier of the samples, which were obtained using ion selective electrode potentiometry after alkaline fusion. A comparison will

Effects of neodymium concentration on optical characteristics of polycrystalline Nd:YAG laser materials

International Nuclear Information System (INIS)

Ikesue, A.; Kamata, K.; Yoshida, K.

1996-01-01

A neodymium-doped yttrium-aluminum garnet (Y 3 Al 5 O 12 , YAG) (Nd:YAG) ceramic that contained 0.3--4.8 at.% neodymium additives and exhibited nearly the same optical properties as those of a single crystal was fabricated by a solid-state reaction method using high-purity powders. Although the integrated absorption intensity of the 2 H 9/2 + 4 F 5/2 bands simply increased as the neodymium concentration in the YAG ceramics decreased, the fluorescence intensity of the 2.4 at.% Nd:YAG ceramic was the strongest among Nd:YAG ceramics with various neodymium concentrations and a 0.9 at.% Nd:YAG single crystal. An oscillation experiment was performed on a continuous-wave (cw) laser with a diode-laser exciting system using those ceramics and the single crystal. The oscillation threshold and slope efficiency in that analysis were 309 mW and 28%, respectively, for the 1.1 at.% Nd:YAG ceramics and 356 mW and 40%, respectively, for the 2.4 at.% Nd:YAG ceramics. The lasing characteristics of the ceramics in the present work were superior to those of a 0.9 at.% Nd:YAG single crystal that was fabricated by the Czochralski (Cz) method

Enzymatic hydrolysis of biomass at high-solids loadings – A review

International Nuclear Information System (INIS)

Modenbach, Alicia A.; Nokes, Sue E.

2013-01-01

Enzymatic hydrolysis is the unit operation in the lignocellulose conversion process that utilizes enzymes to depolymerize lignocellulosic biomass. The saccharide components released are the feedstock for fermentation. When performed at high-solids loadings (≥15% solids, w/w), enzymatic hydrolysis potentially offers many advantages over conversions performed at low- or moderate-solids loadings, including increased sugar and ethanol concentrations and decreased capital and operating costs. The goal of this review is to provide a consolidated source of information on studies using high-solids loadings in enzymatic hydrolysis. Included in this review is a brief discussion of the limitations, such as a lack of available water, difficulty with mixing and handling, insufficient mass and heat transfer, and increased concentration of inhibitors, associated with the use of high solids, as well as descriptions and findings of studies that performed enzymatic hydrolysis at high-solids loadings. Reactors designed and/or equipped for improved handling of high-solids slurries are also discussed. Lastly, this review includes a brief discussion of some of the operations that have successfully scaled-up and implemented high-solids enzymatic hydrolysis at pilot- and demonstration-scale facilities. -- Highlights: •High solids enzymatic hydrolysis needed for conversion process to be cost-effective. •Limitations must be addressed before benefits of high-solid loadings fully realized. •Some success with high-solids loadings at pilot and demonstration scale

Application of rainbow refractometry for measurement of droplets with solid inclusions

Science.gov (United States)

Li, Can; Wu, Xue-cheng; Cao, Jian-zheng; Chen, Ling-hong; Gréhan, Gerard; Cen, Ke-fa

2018-01-01

Characterization of droplets with solid inclusions is of great research interest and has wide industrial applications. Reported here is a theoretical and experimental investigation of the measurement of droplets with solid inclusions using rainbow refractometry. A rainbow extinction model of a droplet with solid inclusions was deduced based on Beer-Lambert's Law. It takes into account the volume concentration, relative size, scattering efficiency of the solid inclusion, and liquid refractive index. An acoustic levitation system for a single droplet and a global rainbow instrumentation system for spray were integrated to study the effect of the H2O-CaCO3 suspension droplets on the rainbow signal and the measured parameters. The results showed that the rainbow encountered unusual disturbances, introduced by the solid inclusions, but its overall structure was not destroyed. Discoveries also included that for volume concentrations of 2.5% or less the CaCO3 particles with diameters below 4 μm had little effect on the measured parameters of the host droplet. The extinction characteristic was also analyzed. The rainbow extinction model failed to quantity the volume concentration of CaCO3, but succeeded in its qualitative analysis.

Log canonical thresholds of smooth Fano threefolds

International Nuclear Information System (INIS)

Cheltsov, Ivan A; Shramov, Konstantin A

2008-01-01

The complex singularity exponent is a local invariant of a holomorphic function determined by the integrability of fractional powers of the function. The log canonical thresholds of effective Q-divisors on normal algebraic varieties are algebraic counterparts of complex singularity exponents. For a Fano variety, these invariants have global analogues. In the former case, it is the so-called α-invariant of Tian; in the latter case, it is the global log canonical threshold of the Fano variety, which is the infimum of log canonical thresholds of all effective Q-divisors numerically equivalent to the anticanonical divisor. An appendix to this paper contains a proof that the global log canonical threshold of a smooth Fano variety coincides with its α-invariant of Tian. The purpose of the paper is to compute the global log canonical thresholds of smooth Fano threefolds (altogether, there are 105 deformation families of such threefolds). The global log canonical thresholds are computed for every smooth threefold in 64 deformation families, and the global log canonical thresholds are computed for a general threefold in 20 deformation families. Some bounds for the global log canonical thresholds are computed for 14 deformation families. Appendix A is due to J.-P. Demailly.

Turbulent solutal convection and surface patterning in solid dissolution

International Nuclear Information System (INIS)

Sullivan, T.S.; Liu, Y.; Ecke, R.E.

1996-01-01

We describe experiments in which crystals of NaCl, KBr, and KCl are dissolved from below by aqueous solutions containing concentrations of the respective salts from zero concentration to near saturation. The solution near the solid-liquid interface is gravitationally unstable, producing turbulent hydrodynamic motion similar to thermal convection from a single surface cooled from above. The coupling of the fluid flow with the solid dissolution produces irregular patterns at the solid-liquid interface with a distribution of horizontal length scales. The dissolution mass flux and the pattern length scales are compared with a turbulent boundary layer model. Remarkable agreement is found, showing that the fluid motion controls both the dissolution rate and the interface patterning. copyright 1996 The American Physical Society

Study of Uranium Concentrations in Water and Organic Material from Streams in Sweden

International Nuclear Information System (INIS)

Ek, J.

1981-12-01

The purpose of the investigation has been to study how uranium concentrations in stream water and organic material are related to various geological parameters such as rock types, average uranium content and radioactivity, fracturing, leachability of uranium from the bedrock, occurrence of uranium mineralisations and thickness and type of Quarternary deposits. The investigation has also taken account of the effects of environmental factors such as climate , precipitation, height above sea level and topography. The background concentration of uranium in organic stream sediment varies from 1 ppm to 45 ppm, with a background value of 10 ppm for all 14 areas considered together. The threshold value for organic stream material varies from 3 ppm U to 303 ppm U with a threshold value of 133 ppm U for all 14 areas considered together. For water, the background concentration varies between the 5 areas from 0.2 ppb U to 0.7 ppb U with a background value of 0.4 ppb U for all 5 areas together. The threshold value varies from 0.3 ppb U to 5.2 ppb U with a threshold value of 2.9 ppb U for all 5 areas together. An investigation of the correlation between uranium concentrations in water and organic stream material from one and the same sampling point shows a positive correlation for high concentrations, but the correlation becomes successively less significant with lower concentrations. Uranium concentrations in organic stream material and water are positively correlated with the following geological parameters:1) Background concentrations of uranium in the bedrock. 2) Abundance of fractures in the bedrock. 3) Leachability of uranium from the bedrock. 4) Presence of uranium mineralisations. For organic stream material, this positive correlation is obtained for both high and low uranium concentrations whereas for water it occurs only with high concentrations. In areas of broken topography and high relief, there is a more clearly defined correlation to the bedrock than in areas of

Bio solids Application on Banana Production: Soil Chemical Properties and Plant Nutrition

International Nuclear Information System (INIS)

Teixeira, L.A.J; Berton, R.S.B; Coscione, A.R; Saes, L.A

2011-01-01

Bio solids are relatively rich in N, P, and S and could be used to substitute mineral fertilization for banana crop. A field experiment was carried out in a Yellow Oxisol to investigate the effects of bio solids application on soil chemical properties and on banana leaf's nutrient concentration during the first cropping cycle. Soil analysis (ph, organic matter, resin P, exchangeable Ca and K, available B, DTPA-extracted micro nutrients, and heavy metals) and index-leaf analysis (B, Cu, Fe, Mn, Zn, Cd, Cr, Ni, and Pb) were evaluated. Bio solids can completely substitute mineral N and P fertilizer to banana growth. Soil exchangeable K and leaf-K concentration must be monitored in order to avoid K deficiency in banana plants. No risk of heavy metal (Cr, Ni, Pb, and Cd) concentration increase in the index leaf was observed when bio solids were applied at the recommended N rate.

Solid-liquid separation in the mining industry

CERN Document Server

Concha A , Fernando

2014-01-01

This book covers virtually all of the engineering science and technological aspects of separating water from particulate solids in the mining industry. It starts with an introduction to the field of mineral processing and the importance of water in mineral concentrators. The consumption of water in the various stages of concentration is discussed, as is the necessity of recovering the majority of that water for recycling. The book presents the fundamentals under which processes of solid-liquid separation are studied, approaching mixtures of discrete finely divided solid particles in water as a basis for dealing with sedimentation in particulate systems. Suspensions, treated as continuous media, provide the basis of sedimentation, flows through porous media and filtration. The book also considers particle aggregations, and thickening is analyzed in depth. Lastly, two chapters cover the fundamentals and application of rheology and the transport of suspensions.  This work is suitable for researchers and profess...

A generalized model for site percolation with two independent concentrations

International Nuclear Information System (INIS)

Lin Jiancheng.

1987-05-01

In this paper the usual site percolation problem with single concentration is generalized to the one that contains two independent concentrations. Using the real space renormalization technique we derive an exact transformation for the one dimensional lattice and a cluster transformation for triangle lattice in two dimensions. The critical exponents and the percolation threshold concentrations obtained are the same as those of the usual single concentration percolation problem. Critical line and flow diagram in the two concentration parameters space are also given. (author). 10 refs, 6 figs

Role of nanoparticles in analytical solid phase microextraction (SPME)

NARCIS (Netherlands)

Zielinska, K.; Leeuwen, van H.P.

2013-01-01

Solid phase microextraction (SPME) is commonly used to measure the free concentration of fairly hydrophobic substances in aqueous media on the basis of their partitioning between sample solution and a solid phase. Here we study the role of nanoparticles that may sorb the analyte in the sample

Threshold Concepts and Information Literacy

Science.gov (United States)

Townsend, Lori; Brunetti, Korey; Hofer, Amy R.

2011-01-01

What do we teach when we teach information literacy in higher education? This paper describes a pedagogical approach to information literacy that helps instructors focus content around transformative learning thresholds. The threshold concept framework holds promise for librarians because it grounds the instructor in the big ideas and underlying…

A Threshold Continuum for Aeolian Sand Transport

Science.gov (United States)

Swann, C.; Ewing, R. C.; Sherman, D. J.

2015-12-01

The threshold of motion for aeolian sand transport marks the initial entrainment of sand particles by the force of the wind. This is typically defined and modeled as a singular wind speed for a given grain size and is based on field and laboratory experimental data. However, the definition of threshold varies significantly between these empirical models, largely because the definition is based on visual-observations of initial grain movement. For example, in his seminal experiments, Bagnold defined threshold of motion when he observed that 100% of the bed was in motion. Others have used 50% and lesser values. Differences in threshold models, in turn, result is large errors in predicting the fluxes associated with sand and dust transport. Here we use a wind tunnel and novel sediment trap to capture the fractions of sand in creep, reptation and saltation at Earth and Mars pressures and show that the threshold of motion for aeolian sand transport is best defined as a continuum in which grains progress through stages defined by the proportion of grains in creep and saltation. We propose the use of scale dependent thresholds modeled by distinct probability distribution functions that differentiate the threshold based on micro to macro scale applications. For example, a geologic timescale application corresponds to a threshold when 100% of the bed in motion whereas a sub-second application corresponds to a threshold when a single particle is set in motion. We provide quantitative measurements (number and mode of particle movement) corresponding to visual observations, percent of bed in motion and degrees of transport intermittency for Earth and Mars. Understanding transport as a continuum provides a basis for revaluating sand transport thresholds on Earth, Mars and Titan.

Volatile trace compounds released from municipal solid waste at the transfer stage: Evaluation of environmental impacts and odour pollution.

Science.gov (United States)

Zhao, Yan; Lu, Wenjing; Wang, Hongtao

2015-12-30

Odour pollution caused by municipal solid waste is a public concern. This study quantitatively evaluated the concentration, environmental impacts, and olfaction of volatile trace compounds released from a waste transfer station. Seventy-six compounds were detected, and ethanol presented the highest releasing rate and ratio of 14.76 kg/d and 12.30 g/t of waste, respectively. Life cycle assessment showed that trichlorofluoromethane and dichlorodifluoromethane accounted for more than 99% of impact potentials to global warming and approximately 70% to human toxicity (non-carcinogenic). The major contributor for both photochemical ozone formation and ecotoxicity was ethanol. A detection threshold method was also used to evaluate odour pollution. Five compounds including methane thiol, hydrogen sulphide, ethanol, dimethyl disulphide, and dimethyl sulphide, with dilution multiples above one, were considered the critical compounds. Methane thiol showed the highest contribution to odour pollution of more than 90%, as indicated by its low threshold. Comparison of the contributions of the compounds to different environmental aspects indicated that typical pollutants varied based on specific evaluation targets and therefore should be comprehensively considered. This study provides important information and scientific methodology to elucidate the impacts of odourant compounds to the environment and odour pollution. Copyright © 2015 Elsevier B.V. All rights reserved.

A New Multistage Lattice Vector Quantization with Adaptive Subband Thresholding for Image Compression

Directory of Open Access Journals (Sweden)

J. Soraghan

2007-01-01

Full Text Available Lattice vector quantization (LVQ reduces coding complexity and computation due to its regular structure. A new multistage LVQ (MLVQ using an adaptive subband thresholding technique is presented and applied to image compression. The technique concentrates on reducing the quantization error of the quantized vectors by “blowing out” the residual quantization errors with an LVQ scale factor. The significant coefficients of each subband are identified using an optimum adaptive thresholding scheme for each subband. A variable length coding procedure using Golomb codes is used to compress the codebook index which produces a very efficient and fast technique for entropy coding. Experimental results using the MLVQ are shown to be significantly better than JPEG 2000 and the recent VQ techniques for various test images.

A New Multistage Lattice Vector Quantization with Adaptive Subband Thresholding for Image Compression

Directory of Open Access Journals (Sweden)

Salleh MFM

2007-01-01

Full Text Available Lattice vector quantization (LVQ reduces coding complexity and computation due to its regular structure. A new multistage LVQ (MLVQ using an adaptive subband thresholding technique is presented and applied to image compression. The technique concentrates on reducing the quantization error of the quantized vectors by "blowing out" the residual quantization errors with an LVQ scale factor. The significant coefficients of each subband are identified using an optimum adaptive thresholding scheme for each subband. A variable length coding procedure using Golomb codes is used to compress the codebook index which produces a very efficient and fast technique for entropy coding. Experimental results using the MLVQ are shown to be significantly better than JPEG 2000 and the recent VQ techniques for various test images.

Acute effects of dynamic exercises on the relationship between the motor unit firing rate and the recruitment threshold.

Science.gov (United States)

Ye, Xin; Beck, Travis W; DeFreitas, Jason M; Wages, Nathan P

2015-04-01

The aim of this study was to compare the acute effects of concentric versus eccentric exercise on motor control strategies. Fifteen men performed six sets of 10 repetitions of maximal concentric exercises or eccentric isokinetic exercises with their dominant elbow flexors on separate experimental visits. Before and after the exercise, maximal strength testing and submaximal trapezoid isometric contractions (40% of the maximal force) were performed. Both exercise conditions caused significant strength loss in the elbow flexors, but the loss was greater following the eccentric exercise (t=2.401, P=.031). The surface electromyographic signals obtained from the submaximal trapezoid isometric contractions were decomposed into individual motor unit action potential trains. For each submaximal trapezoid isometric contraction, the relationship between the average motor unit firing rate and the recruitment threshold was examined using linear regression analysis. In contrast to the concentric exercise, which did not cause significant changes in the mean linear slope coefficient and y-intercept of the linear regression line, the eccentric exercise resulted in a lower mean linear slope and an increased mean y-intercept, thereby indicating that increasing the firing rates of low-threshold motor units may be more important than recruiting high-threshold motor units to compensate for eccentric exercise-induced strength loss. Copyright © 2014 Elsevier B.V. All rights reserved.

???????????? SolidWorks/SolidWorks Flow Simulation/SolidWorks Simulation ??? ?????????? ???????? ?? ????????????? ???

OpenAIRE

????????????, ?. ?.; ????????, ?. ?.; ?????, ?. ?.

2012-01-01

? ?????? ???????? ??????? ??????? ???????? ?? ???????????? ??????????? ????????? SolidWorks/SolidWorks Flow Simulation (COSMOSFloWorks)/SolidWorks Simulation ??? ?????????? ???????? ?? ????????????? ???. ??? ???????? ????????? ???????? ?????????? ?? ?????? ???????? ??????? ? ????????????? ?????? ? ????????????? ????????????? ?????????? ???????????? SolidWorks Flow Simulation (COSMOSFloWorks). ??? ???????????? ??????????? ????????????? ?????? ?? ????????? ??????????? ??????? ?? ??????????? ...

Iran: the next nuclear threshold state?

OpenAIRE

Maurer, Christopher L.

2014-01-01

Approved for public release; distribution is unlimited A nuclear threshold state is one that could quickly operationalize its peaceful nuclear program into one capable of producing a nuclear weapon. This thesis compares two known threshold states, Japan and Brazil, with Iran to determine if the Islamic Republic could also be labeled a threshold state. Furthermore, it highlights the implications such a status could have on U.S. nonproliferation policy. Although Iran's nuclear program is mir...

Microelectronics: Atoms diffusion in solid state. Part 1

International Nuclear Information System (INIS)

Lopez Higuera, J.M.

1988-01-01

The fundamentals on which the technology for the diffusion of impurities in solid state is based, is presented. This technology is widely used to produce controlled and localized concentrations of atoms of the mentioned impurities in base solids in order to obtain those characteristics which may lead to the implementation of electronic, optoelectronic and electrooptic devices. (Author)

Can we set a global threshold age to define mature forests?

DEFF Research Database (Denmark)

Martin, Philip; Jung, Martin; Brearley, Francis Q.

2016-01-01

) whether we can set a threshold age for mature forests. Using data from previously published studies we modelled the impacts of forest age and climate on BD using linear mixed effects models. We examined the potential biases in the dataset by comparing how representative it was of global mature forests......Globally, mature forests appear to be increasing in biomass density (BD). There is disagreement whether these increases are the result of increases in atmospheric CO2 concentrations or a legacy effect of previous land-use. Recently, it was suggested that a threshold of 450 years should be used...... to define mature forests and that many forests increasing in BD may be younger than this. However, the study making these suggestions failed to account for the interactions between forest age and climate. Here we revisit the issue to identify: (1) how climate and forest age control global forest BD and (2...

High concentration agglomerate dynamics at high temperatures.

Science.gov (United States)

Heine, M C; Pratsinis, S E

2006-11-21

The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

Hydrometeorological threshold conditions for debris flow initiation in Norway

Directory of Open Access Journals (Sweden)

N. K. Meyer

2012-10-01

Full Text Available Debris flows, triggered by extreme precipitation events and rapid snow melt, cause considerable damage to the Norwegian infrastructure every year. To define intensity-duration (ID thresholds for debris flow initiation critical water supply conditions arising from intensive rainfall or snow melt were assessed on the basis of daily hydro-meteorological information for 502 documented debris flow events. Two threshold types were computed: one based on absolute ID relationships and one using ID relationships normalized by the local precipitation day normal (PDN. For each threshold type, minimum, medium and maximum threshold values were defined by fitting power law curves along the 10th, 50th and 90th percentiles of the data population. Depending on the duration of the event, the absolute threshold intensities needed for debris flow initiation vary between 15 and 107 mm day⁻¹. Since the PDN changes locally, the normalized thresholds show spatial variations. Depending on location, duration and threshold level, the normalized threshold intensities vary between 6 and 250 mm day⁻¹. The thresholds obtained were used for a frequency analysis of over-threshold events giving an estimation of the exceedance probability and thus potential for debris flow events in different parts of Norway. The absolute thresholds are most often exceeded along the west coast, while the normalized thresholds are most frequently exceeded on the west-facing slopes of the Norwegian mountain ranges. The minimum thresholds derived in this study are in the range of other thresholds obtained for regions with a climate comparable to Norway. Statistics reveal that the normalized threshold is more reliable than the absolute threshold as the former shows no spatial clustering of debris flows related to water supply events captured by the threshold.

Threshold-voltage modulated phase change heterojunction for application of high density memory

International Nuclear Information System (INIS)

Yan, Baihan; Tong, Hao; Qian, Hang; Miao, Xiangshui

2015-01-01

Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-ray photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current

Threshold-voltage modulated phase change heterojunction for application of high density memory

Science.gov (United States)

Yan, Baihan; Tong, Hao; Qian, Hang; Miao, Xiangshui

2015-09-01

Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-ray photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current.

On flows of viscoelastic fluids under threshold-slip boundary conditions

Science.gov (United States)

Baranovskii, E. S.

2018-03-01

We investigate a boundary-value problem for the steady isothermal flow of an incompressible viscoelastic fluid of Oldroyd type in a 3D bounded domain with impermeable walls. We use the Fujita threshold-slip boundary condition. This condition states that the fluid can slip along a solid surface when the shear stresses reach a certain critical value; otherwise the slipping velocity is zero. Assuming that the flow domain is not rotationally symmetric, we prove an existence theorem for the corresponding slip problem in the framework of weak solutions. The proof uses methods for solving variational inequalities with pseudo-monotone operators and convex functionals, the method of introduction of auxiliary viscosity, as well as a passage-to-limit procedure based on energy estimates of approximate solutions, Korn’s inequality, and compactness arguments. Also, some properties and estimates of weak solutions are established.

Bone sarcoma in humans induced by radium: A threshold response?

International Nuclear Information System (INIS)

Rowland, R.E.

1996-01-01

The radium 226 and radium 228 have induced malignancies in the skeleton (primarily bone sarcomas) of humans. They have also induced carcinomas in the paranasal sinuses and mastoid air cells. There is no evidence that any leukemias or any other solid cancers have been induced by internally deposited radium. This paper discuses a study conducted on the dial painter population. This study made a concerted effort to verify, for each of the measured radium cases, the published values of the skeletal dose and the initial intake of radium. These were derived from body content measurements made some 40 years after the radium intake. Corrections to the assumed radium retention function resulted in a considerable number of dose changes. These changes have changed the shape of the dose response function. It now appears that the induction of bone sarcomas is a threshold process

Cadmium and other heavy metal concentrations in bovine kidneys in the Republic of Ireland

Energy Technology Data Exchange (ETDEWEB)

Canty, Mary J., E-mail: mary.canty@agriculture.gov.ie [Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4 (Ireland); Department of Agriculture, Food and the Marine, Backweston Campus, Celbridge, Co. Kildare (Ireland); Scanlon, Aiden, E-mail: aiden.scanlon@agriculture.gov.ie [Department of Agriculture, Food and the Marine, Agriculture House, Kildare St, Dublin 2 (Ireland); Collins, Daniel M., E-mail: daniel.collins@ucd.ie [Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4 (Ireland); McGrath, Guy, E-mail: guy.mcgrath@ucd.ie [Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4 (Ireland); Clegg, Tracy A., E-mail: tracy.clegg@ucd.ie [Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4 (Ireland); Lane, Elizabeth, E-mail: elizabeth.lane@agriculture.gov.ie [Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4 (Ireland); Department of Agriculture, Food and the Marine, Backweston Campus, Celbridge, Co. Kildare (Ireland); Sheridan, Michael K., E-mail: michael.sheridan@agriculture.gov.ie [Department of Agriculture, Food and the Marine, Agriculture House, Kildare St, Dublin 2 (Ireland); More, Simon J., E-mail: simon.more@ucd.ie [Centre for Veterinary Epidemiology and Risk Analysis (CVERA), UCD School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4 (Ireland)

2014-07-01

In Ireland, an estimated 15% of Irish soils exceed the EU threshold limit for soil Cd of 1 mg/kg. The aim was to determine the concentrations of Cd and other heavy metals (As, Hg and Pb) in kidneys collected from cattle at slaughter. Systematic sampling of eligible animals (animals that were born and reared until slaughter in the same Irish county) at the time of slaughter was conducted, until a threshold number of animals from all 26 counties and 6 age categories was reached. A predictive surface of soil Cd was generated, by kriging the Cd values of 1310 previously reported soil samples. A linear regression weighted model was developed to model kidney Cd concentration, using the risk factors of age, sex, breed, province and estimated soil Cd concentration. Kidney Cd (n = 393) concentrations varied between 0.040 and 8.630 mg/kg wet weight; while concentrations of As, Hg and Pb were low. The estimated weighted proportion of animals with a high (≥ 1 mg/kg) kidney Cd concentration was 11.25% (95% CI: 8.63–14.53%). Key predictors for high kidney Cd concentration were soil Cd, animal age and province. At a soil Cd concentration of 1.5 mg/kg, it was predicted that an age threshold to avoid exceeding a kidney Cd concentration of 1 mg/kg in most animals would be ∼ 3 y in Connacht, > 4 y in Ulster, and > 5 y in Leinster and Munster. In naturally occurring areas of high Cd levels in soils in Ireland, the Cd level in bovine kidneys can exceed the current EU ML of 1 mg/kg in older animals. Kidneys of most cattle under three years of age will conform with EU requirements. - Highlights: • An estimated 15% of Irish soils exceed the EU Cd threshold limit of 1 mg/kg. • 11.3% of cattle had kidney Cd concentrations in excess of the EU ML of 1 mg/kg. • Age, soil Cd concentrations and region were key predictors of elevated kidney Cd. • Kidneys of most Irish cattle under three years of age will conform with EU requirements.

Feasibility Studies on Pipeline Disposal of Concentrated Copper Tailings Slurry for Waste Minimization

Science.gov (United States)

Senapati, Pradipta Kumar; Mishra, Barada Kanta

2017-06-01

The conventional lean phase copper tailings slurry disposal systems create pollution all around the disposal area through seepage and flooding of waste slurry water. In order to reduce water consumption and minimize pollution, the pipeline disposal of these waste slurries at high solids concentrations may be considered as a viable option. The paper presents the rheological and pipeline flow characteristics of copper tailings samples in the solids concentration range of 65-72 % by weight. The tailings slurry indicated non-Newtonian behaviour at these solids concentrations and the rheological data were best fitted by Bingham plastic model. The influence of solids concentration on yield stress and plastic viscosity for the copper tailings samples were discussed. Using a high concentration test loop, pipeline experiments were conducted in a 50 mm nominal bore (NB) pipe by varying the pipe flow velocity from 1.5 to 3.5 m/s. A non-Newtonian Bingham plastic pressure drop model predicted the experimental data reasonably well for the concentrated tailings slurry. The pressure drop model was used for higher size pipes and the operating conditions for pipeline disposal of concentrated copper tailings slurry in a 200 mm NB pipe with respect to specific power consumption were discussed.

11 CFR 9036.1 - Threshold submission.

Science.gov (United States)

2010-01-01

... credit or debit card, including one made over the Internet, the candidate shall provide sufficient... section shall not count toward the threshold amount. (c) Threshold certification by Commission. (1) After...

Validity of Lactate Thresholds in Inline Speed Skating.

Science.gov (United States)

Hecksteden, Anne; Heinze, Tobias; Faude, Oliver; Kindermann, Wilfried; Meyer, Tim

2015-09-01

Lactate thresholds are commonly used as estimates of the highest workload where lactate production and elimination are in equilibrium (maximum lactate steady state [MLSS]). However, because of the high static load on propulsive muscles, lactate kinetics in inline speed skating may differ significantly from other endurance exercise modes. Therefore, the discipline-specific validity of lactate thresholds has to be verified. Sixteen competitive inline-speed skaters (age: 30 ± 10 years; training per week: 10 ± 4 hours) completed an exhaustive stepwise incremental exercise test (start 24 km·h, step duration 3 minutes, increment 2 km·h) to determine individual anaerobic threshold (IAT) and the workload corresponding to a blood lactate concentration of 4 mmol·L (LT4) and 2-5 continuous load tests of (up to) 30 minutes to determine MLSS. The IAT and LT4 correlated significantly with MLSS, and the mean differences were almost negligible (MLSS 29.5 ± 2.5 km·h; IAT 29.2 ± 2.0 km·h; LT4 29.6 ± 2.3 km·h; p > 0.1 for all differences). However, the variability of differences was considerable resulting in 95% limits of agreement in the upper range of values known from other endurance disciplines (2.6 km·h [8.8%] for IAT and 3.1 km·h [10.3%] for LT4). Consequently, IAT and LT4 may be considered as valid estimates of the MLSS in inline speed skating, but verification by means of a constant load test should be considered in cases of doubt or when optimal accuracy is needed (e.g., in elite athletes or scientific studies).

Radiation induced homogeneous precipitation in undersaturated solid-solutions

International Nuclear Information System (INIS)

Cauvin, Richard; Martin, Georges.

1978-01-01

The stability of various types of solid solutions under irradiation is studied. In this paper, observations made on AlZn solid solutions under 1 MeV electron irradiation are reported. Al-Zn was chosen as a prototype of solid solutions with a simple miscibility gap. It is shown that under appropriate irradiation conditions undersaturated AnZn solid solutions give rise to a homogeneous precipitation of coherent G.P. zones and of incoherent Zn precipitates the atomic volume of which is smaller than that of the matrix. We propose a more general treatment of solute concentration heterogeneities in solid solutions under irradiation and suggest how it might account for the nucleation of the observed phases. The growth of the observed precipitates is studied

Is there a threshold concentration of cat allergen exposure on respiratory symptoms in adults?

NARCIS (Netherlands)

Chen, C.M.; Thiering, E.; Zock, J.P.; Villani, S.; Olivieri, M.; Modig, L.; Jarvis, D.; Norbäck, D.; Verlato, G.; Heinrich, J.

2015-01-01

Background and Objective: Cat allergen concentrations higher than 8 μg/g in settled house dust, have been suggested to provoke exacerbation of allergic respiratory symptoms. However, whether the 8μg/g of indoor cat allergen concentration is indeed the minimal exposure required for triggering the

High-frequency (8 to 16 kHz) reference thresholds and intrasubject threshold variability relative to ototoxicity criteria using a Sennheiser HDA 200 earphone.

Science.gov (United States)

Frank, T

2001-04-01

The first purpose of this study was to determine high-frequency (8 to 16 kHz) thresholds for standardizing reference equivalent threshold sound pressure levels (RETSPLs) for a Sennheiser HDA 200 earphone. The second and perhaps more important purpose of this study was to determine whether repeated high-frequency thresholds using a Sennheiser HDA 200 earphone had a lower intrasubject threshold variability than the ASHA 1994 significant threshold shift criteria for ototoxicity. High-frequency thresholds (8 to 16 kHz) were obtained for 100 (50 male, 50 female) normally hearing (0.25 to 8 kHz) young adults (mean age of 21.2 yr) in four separate test sessions using a Sennheiser HDA 200 earphone. The mean and median high-frequency thresholds were similar for each test session and increased as frequency increased. At each frequency, the high-frequency thresholds were not significantly (p > 0.05) different for gender, test ear, or test session. The median thresholds at each frequency were similar to the 1998 interim ISO RETSPLs; however, large standard deviations and wide threshold distributions indicated very high intersubject threshold variability, especially at 14 and 16 kHz. Threshold repeatability was determined by finding the threshold differences between each possible test session comparison (N = 6). About 98% of all of the threshold differences were within a clinically acceptable range of +/-10 dB from 8 to 14 kHz. The threshold differences between each subject's second, third, and fourth minus their first test session were also found to determine whether intrasubject threshold variability was less than the ASHA 1994 criteria for determining a significant threshold shift due to ototoxicity. The results indicated a false-positive rate of 0% for a threshold shift > or = 20 dB at any frequency and a false-positive rate of 2% for a threshold shift >10 dB at two consecutive frequencies. This study verified that the output of high-frequency audiometers at 0 dB HL using

Incorporation of trace elements in Portland cement clinker: Thresholds limits for Cu, Ni, Sn or Zn

International Nuclear Information System (INIS)

Gineys, N.; Aouad, G.; Sorrentino, F.; Damidot, D.

2011-01-01

This paper aims at defining precisely, the threshold limits for several trace elements (Cu, Ni, Sn or Zn) which correspond to the maximum amount that could be incorporated into a standard clinker whilst reaching the limit of solid solution of its four major phases (C 3 S, C 2 S, C 3 A and C 4 AF). These threshold limits were investigated through laboratory synthesised clinkers that were mainly studied by X-ray Diffraction and Scanning Electron Microscopy. The reference clinker was close to a typical Portland clinker (65% C 3 S, 18% C 2 S, 8% C 3 A and 8% C 4 AF). The threshold limits for Cu, Ni, Zn and Sn are quite high with respect to the current contents in clinker and were respectively equal to 0.35, 0.5, 0.7 and 1 wt.%. It appeared that beyond the defined threshold limits, trace elements had different behaviours. Ni was associated with Mg as a magnesium nickel oxide (MgNiO 2 ) and Sn reacted with lime to form a calcium stannate (Ca 2 SnO 4 ). Cu changed the crystallisation process and affected therefore the formation of C 3 S. Indeed a high content of Cu in clinker led to the decomposition of C 3 S into C 2 S and of free lime. Zn, in turn, affected the formation of C 3 A. Ca 6 Zn 3 Al 4 O 15 was formed whilst a tremendous reduction of C 3 A content was identified. The reactivity of cements made with the clinkers at the threshold limits was followed by calorimetry and compressive strength measurements on cement paste. The results revealed that the doped cements were at least as reactive as the reference cement.

Direct observation of solid-phase adsorbate concentration profile in powdered activated carbon particle to elucidate mechanism of high adsorption capacity on super-powdered activated carbon.

Science.gov (United States)

Ando, Naoya; Matsui, Yoshihiko; Matsushita, Taku; Ohno, Koichi

2011-01-01

Decreasing the particle size of powdered activated carbon (PAC) by pulverization increases its adsorption capacities for natural organic matter (NOM) and polystyrene sulfonate (PSS, which is used as a model adsorbate). A shell adsorption mechanism in which NOM and PSS molecules do not completely penetrate the adsorbent particle and instead preferentially adsorb near the outer surface of the particle has been proposed as an explanation for this adsorption capacity increase. In this report, we present direct evidence to support the shell adsorption mechanism. PAC particles containing adsorbed PSS were sectioned with a focused ion beam, and the solid-phase PSS concentration profiles of the particle cross-sections were directly observed by means of field emission-scanning electron microscopy/energy-dispersive X-ray spectrometry (FE-SEM/EDXS). X-ray emission from sulfur, an index of PSS concentration, was higher in the shell region than in the inner region of the particles. The X-ray emission profile observed by EDXS did not agree completely with the solid-phase PSS concentration profile predicted by shell adsorption model analysis of the PSS isotherm data, but the observed and predicted profiles were not inconsistent when the analytical errors were considered. These EDXS results provide the first direct evidence that PSS is adsorbed mainly in the vicinity of the external surface of the PAC particles, and thus the results support the proposition that the increase in NOM and PSS adsorption capacity with decreasing particle size is due to the increase in external surface area on which the molecules can be adsorbed. Copyright © 2010 Elsevier Ltd. All rights reserved.

Thermotactile perception thresholds measurement conditions.

Science.gov (United States)

Maeda, Setsuo; Sakakibara, Hisataka

2002-10-01

The purpose of this paper is to investigate the effects of posture, push force and rate of temperature change on thermotactile thresholds and to clarify suitable measuring conditions for Japanese people. Thermotactile (warm and cold) thresholds on the right middle finger were measured with an HVLab thermal aesthesiometer. Subjects were eight healthy male Japanese students. The effects of posture in measurement were examined in the posture of a straight hand and forearm placed on a support, the same posture without a support, and the fingers and hand flexed at the wrist with the elbow placed on a desk. The finger push force applied to the applicator of the thermal aesthesiometer was controlled at a 0.5, 1.0, 2.0 and 3.0 N. The applicator temperature was changed to 0.5, 1.0, 1.5, 2.0 and 2.5 degrees C/s. After each measurement, subjects were asked about comfort under the measuring conditions. Three series of experiments were conducted on different days to evaluate repeatability. Repeated measures ANOVA showed that warm thresholds were affected by the push force and the rate of temperature change and that cold thresholds were influenced by posture and push force. The comfort assessment indicated that the measurement posture of a straight hand and forearm laid on a support was the most comfortable for the subjects. Relatively high repeatability was obtained under measurement conditions of a 1 degrees C/s temperature change rate and a 0.5 N push force. Measurement posture, push force and rate of temperature change can affect the thermal threshold. Judging from the repeatability, a push force of 0.5 N and a temperature change of 1.0 degrees C/s in the posture with the straight hand and forearm laid on a support are recommended for warm and cold threshold measurements.

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

Science.gov (United States)

Black, R.W.; Moran, P.W.; Frankforter, J.D.

2011-01-01

Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. Although nutrients typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria. ?? 2010 The Author(s).

Validation and application of the methodology for analysis of radon concentration in the air through the technique of solid state nuclear track detectors (SSNTD)

International Nuclear Information System (INIS)

Carvalho, Caroline de; Comissao Nacional de Energia Nuclear; Silva, Nivaldo Carlos da

2011-01-01

Radon is a radioactive noble gas that occurs naturally in soil and could enter into residential. The decay products of radon are radioactive metals which, when inhaled, can be retained in the respiratory system, leading to an internal dose of radiation. The monitoring of radon levels in residences and workplaces is extremely important, since high concentrations of this gas can cause serious public health problems. This study analyzed the concentration of radon in the air in 94 work environments at the Laboratory of Pocos de Caldas - LAPOC/CNEN, including laboratories, administrative rooms, workshop, warehouse and guardhouse. The method employed in the monitoring was the technique of solid state nuclear track detectors, known as SSNTD. For calibration and validation of this method, controlled experiments were conducted in laboratory with specific instrumentation. The monitoring results indicated that most environments present radon concentrations above 100 Bq m -3 , which is the reference level recommended by the World Health Organization. (author)

Validation and application of the methodology for analysis of radon concentration in the air through the technique of solid state nuclear track detectors (SSNTD)

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Caroline de [Pontificia Universidade Catolica de Minas Gerais (PUC-Pocos), Pocos de Caldas, MG (Brazil); Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas; Silva, Nivaldo Carlos da, E-mail: ncsilva@cnen.gov.b [Comissao Nacional de Energia Nuclear (LAPOC/CNEN), Pocos de Caldas, MG (Brazil). Lab. de Pocos de Caldas

2011-07-01

Radon is a radioactive noble gas that occurs naturally in soil and could enter into residential. The decay products of radon are radioactive metals which, when inhaled, can be retained in the respiratory system, leading to an internal dose of radiation. The monitoring of radon levels in residences and workplaces is extremely important, since high concentrations of this gas can cause serious public health problems. This study analyzed the concentration of radon in the air in 94 work environments at the Laboratory of Pocos de Caldas - LAPOC/CNEN, including laboratories, administrative rooms, workshop, warehouse and guardhouse. The method employed in the monitoring was the technique of solid state nuclear track detectors, known as SSNTD. For calibration and validation of this method, controlled experiments were conducted in laboratory with specific instrumentation. The monitoring results indicated that most environments present radon concentrations above 100 Bq m{sup -3}, which is the reference level recommended by the World Health Organization. (author)

Doubler system quench detection threshold

International Nuclear Information System (INIS)

Kuepke, K.; Kuchnir, M.; Martin, P.

1983-01-01

The experimental study leading to the determination of the sensitivity needed for protecting the Fermilab Doubler from damage during quenches is presented. The quench voltage thresholds involved were obtained from measurements made on Doubler cable of resistance x temperature and voltage x time during quenches under several currents and from data collected during operation of the Doubler Quench Protection System as implemented in the B-12 string of 20 magnets. At 4kA, a quench voltage threshold in excess of 5.OV will limit the peak Doubler cable temperature to 452K for quenches originating in the magnet coils whereas a threshold of 0.5V is required for quenches originating outside of coils

Drug delivery properties of macroporous polystyrene solid foams.

Science.gov (United States)

Canal, Cristina; Aparicio, Rosa Maria; Vilchez, Alejandro; Esquena, Jordi; García-Celma, Maria José

2012-01-01

Polymeric porous foams have been evaluated as possible new pharmaceutical dosage forms. These materials were obtained by polymerization in the continuous phase of highly concentrated emulsions prepared by the phase inversion temperature method. Their porosity, specific surface and surface topography were characterized, and the incorporation and release of active principles was studied using ketoprofen as model lipophilic molecule. Solid foams with very high pore volume, mainly inside macropores, were obtained by this method. The pore morphology of the materials was characterized, and very rough topography was observed, which contributed to their nearly superhydrophobic properties. These solid foams could be used as delivery systems for active principles with pharmaceutical interest, and in the present work ketoprofen was used as a model lipophilic molecule. Drug incorporation and release was studied from solid foam disks, using different concentrations of the loading solutions, achieving a delayed release with short lag-time.

Factors modifying sensitivity to carcinogens and the problem of threshold in carcinogenesis

International Nuclear Information System (INIS)

Anisimov, V.N.

1983-01-01

Maximum allowable concentrations of chemical carcinogens and dose rates of ionizing radiation have been under extensive study both experimentally and epidemiologically. The problem of the carcinogenic hazards of low-level radiation is a very difficult one: in epidemiological studies it is hard to take into account the many factors (e.g. diseases, diet, genetic peculiarities) that may affect sensitivity to radiation; in experimental studies it is hard to extrapolate with accuracy from one species to another or from the individual threshold to that of the whole population. Age, enzyme activity, sex, and DNA repair capability also modify sensitivity to radiation; when factors such as these are better understood it is expected that epidemiological studies will give a solution that allows estimation of the carcinogenic risk from low-level radiation and hence establishment of a threshold dose. (author)

Experimental Methods to Estimate Accumulated Solids in Nuclear Waste Tanks - 13313

Energy Technology Data Exchange (ETDEWEB)

Duignan, Mark R.; Steeper, Timothy J.; Steimke, John L. [Savannah River Nuclear Solutions, Savannah River National Laboratory, Aiken, SC 29808 (United States)

2013-07-01

The Department of Energy has a large number of nuclear waste tanks. It is important to know if fissionable materials can concentrate when waste is transferred from staging tanks prior to feeding waste treatment plants. Specifically, there is a concern that large, dense particles, e.g., plutonium containing, could accumulate in poorly mixed regions of a blend tank heel for tanks that employ mixing jet pumps. At the request of the DOE Hanford Tank Operations Contractor, Washington River Protection Solutions, the Engineering Development Laboratory of the Savannah River National Laboratory performed a scouting study in a 1/22-scale model of a waste tank to investigate this concern and to develop measurement techniques that could be applied in a more extensive study at a larger scale. Simulated waste tank solids and supernatant were charged to the test tank and rotating liquid jets were used to remove most of the solids. Then the volume and shape of the residual solids and the spatial concentration profiles for the surrogate for plutonium were measured. This paper discusses the overall test results, which indicated heavy solids only accumulate during the first few transfer cycles, along with the techniques and equipment designed and employed in the test. Those techniques include: - Magnetic particle separator to remove stainless steel solids, the plutonium surrogate from a flowing stream. - Magnetic wand used to manually remove stainless steel solids from samples and the tank heel. - Photographs were used to determine the volume and shape of the solids mounds by developing a composite of topographical areas. - Laser range finders to determine the volume and shape of the solids mounds. - Core sampler to determine the stainless steel solids distribution within the solids mounds. - Computer driven positioner that placed the laser range finders and the core sampler over solids mounds that accumulated on the bottom of a scaled staging tank in locations where jet velocities

Reaction thresholds in doubly special relativity

International Nuclear Information System (INIS)

Heyman, Daniel; Major, Seth; Hinteleitner, Franz

2004-01-01

Two theories of special relativity with an additional invariant scale, 'doubly special relativity', are tested with calculations of particle process kinematics. Using the Judes-Visser modified conservation laws, thresholds are studied in both theories. In contrast with some linear approximations, which allow for particle processes forbidden in special relativity, both the Amelino-Camelia and Magueijo-Smolin frameworks allow no additional processes. To first order, the Amelino-Camelia framework thresholds are lowered and the Magueijo-Smolin framework thresholds may be raised or lowered

Solid oxide electrochemical reactor science.

Energy Technology Data Exchange (ETDEWEB)

Sullivan, Neal P. (Colorado School of Mines, Golden, CO); Stechel, Ellen Beth; Moyer, Connor J. (Colorado School of Mines, Golden, CO); Ambrosini, Andrea; Key, Robert J. (Colorado School of Mines, Golden, CO)

2010-09-01

Solid-oxide electrochemical cells are an exciting new technology. Development of solid-oxide cells (SOCs) has advanced considerable in recent years and continues to progress rapidly. This thesis studies several aspects of SOCs and contributes useful information to their continued development. This LDRD involved a collaboration between Sandia and the Colorado School of Mines (CSM) ins solid-oxide electrochemical reactors targeted at solid oxide electrolyzer cells (SOEC), which are the reverse of solid-oxide fuel cells (SOFC). SOECs complement Sandia's efforts in thermochemical production of alternative fuels. An SOEC technology would co-electrolyze carbon dioxide (CO{sub 2}) with steam at temperatures around 800 C to form synthesis gas (H{sub 2} and CO), which forms the building blocks for a petrochemical substitutes that can be used to power vehicles or in distributed energy platforms. The effort described here concentrates on research concerning catalytic chemistry, charge-transfer chemistry, and optimal cell-architecture. technical scope included computational modeling, materials development, and experimental evaluation. The project engaged the Colorado Fuel Cell Center at CSM through the support of a graduate student (Connor Moyer) at CSM and his advisors (Profs. Robert Kee and Neal Sullivan) in collaboration with Sandia.

Genotoxic thresholds, DNA repair, and susceptibility in human populations

International Nuclear Information System (INIS)

Jenkins, Gareth J.S.; Zair, Zoulikha; Johnson, George E.; Doak, Shareen H.

2010-01-01

It has been long assumed that DNA damage is induced in a linear manner with respect to the dose of a direct acting genotoxin. Thus, it is implied that direct acting genotoxic agents induce DNA damage at even the lowest of concentrations and that no 'safe' dose range exists. The linear (non-threshold) paradigm has led to the one-hit model being developed. This 'one hit' scenario can be interpreted such that a single DNA damaging event in a cell has the capability to induce a single point mutation in that cell which could (if positioned in a key growth controlling gene) lead to increased proliferation, leading ultimately to the formation of a tumour. There are many groups (including our own) who, for a decade or more, have argued, that low dose exposures to direct acting genotoxins may be tolerated by cells through homeostatic mechanisms such as DNA repair. This argument stems from the existence of evolutionary adaptive mechanisms that allow organisms to adapt to low levels of exogenous sources of genotoxins. We have been particularly interested in the genotoxic effects of known mutagens at low dose exposures in human cells and have identified for the first time, in vitro genotoxic thresholds for several mutagenic alkylating agents (Doak et al., 2007). Our working hypothesis is that DNA repair is primarily responsible for these thresholded effects at low doses by removing low levels of DNA damage but becoming saturated at higher doses. We are currently assessing the roles of base excision repair (BER) and methylguanine-DNA methyltransferase (MGMT) for roles in the identified thresholds (Doak et al., 2008). This research area is currently important as it assesses whether 'safe' exposure levels to mutagenic chemicals can exist and allows risk assessment using appropriate safety factors to define such exposure levels. Given human variation, the mechanistic basis for genotoxic thresholds (e.g. DNA repair) has to be well defined in order that susceptible individuals are

Thresholds in chemical respiratory sensitisation.

Science.gov (United States)

Cochrane, Stella A; Arts, Josje H E; Ehnes, Colin; Hindle, Stuart; Hollnagel, Heli M; Poole, Alan; Suto, Hidenori; Kimber, Ian

2015-07-03

There is a continuing interest in determining whether it is possible to identify thresholds for chemical allergy. Here allergic sensitisation of the respiratory tract by chemicals is considered in this context. This is an important occupational health problem, being associated with rhinitis and asthma, and in addition provides toxicologists and risk assessors with a number of challenges. In common with all forms of allergic disease chemical respiratory allergy develops in two phases. In the first (induction) phase exposure to a chemical allergen (by an appropriate route of exposure) causes immunological priming and sensitisation of the respiratory tract. The second (elicitation) phase is triggered if a sensitised subject is exposed subsequently to the same chemical allergen via inhalation. A secondary immune response will be provoked in the respiratory tract resulting in inflammation and the signs and symptoms of a respiratory hypersensitivity reaction. In this article attention has focused on the identification of threshold values during the acquisition of sensitisation. Current mechanistic understanding of allergy is such that it can be assumed that the development of sensitisation (and also the elicitation of an allergic reaction) is a threshold phenomenon; there will be levels of exposure below which sensitisation will not be acquired. That is, all immune responses, including allergic sensitisation, have threshold requirement for the availability of antigen/allergen, below which a response will fail to develop. The issue addressed here is whether there are methods available or clinical/epidemiological data that permit the identification of such thresholds. This document reviews briefly relevant human studies of occupational asthma, and experimental models that have been developed (or are being developed) for the identification and characterisation of chemical respiratory allergens. The main conclusion drawn is that although there is evidence that the

Polymer Percolation Threshold in Multi-Component HPMC Matrices Tablets

Directory of Open Access Journals (Sweden)

Maryam Maghsoodi

2011-06-01

Full Text Available Introduction: The percolation theory studies the critical points or percolation thresholds of the system, where onecomponent of the system undergoes a geometrical phase transition, starting to connect the whole system. The application of this theory to study the release rate of hydrophilic matrices allows toexplain the changes in release kinetics of swellable matrix type system and results in a clear improvement of the design of controlled release dosage forms. Methods: In this study, the percolation theory has been applied to multi-component hydroxypropylmethylcellulose (HPMC hydrophilic matrices. Matrix tablets have been prepared using phenobarbital as drug,magnesium stearate as a lubricant employing different amount of lactose and HPMC K4M as a fillerandmatrix forming material, respectively. Ethylcelullose (EC as a polymeric excipient was also examined. Dissolution studies were carried out using the paddle method. In order to estimate the percolation threshold, the behaviour of the kinetic parameters with respect to the volumetric fraction of HPMC at time zero, was studied. Results: In both HPMC/lactose and HPMC/EC/lactose matrices, from the point of view of the percolation theory, the optimum concentration for HPMC, to obtain a hydrophilic matrix system for the controlled release of phenobarbital is higher than 18.1% (v/v HPMC. Above 18.1% (v/v HPMC, an infinite cluster of HPMC would be formed maintaining integrity of the system and controlling the drug release from the matrices. According to results, EC had no significant influence on the HPMC percolation threshold. Conclusion: This may be related to broad functionality of the swelling hydrophilic matrices.

Comparison of the multicomponent mass transfer models for the prediction of the concentration overpotential for solid oxide fuel cell anodes

Energy Technology Data Exchange (ETDEWEB)

Vural, Yasemin; Ma, Lin; Ingham, Derek B.; Pourkashanian, Mohamed [Centre for Computational Fluid Dynamics, University of Leeds, Leeds (United Kingdom)

2010-08-01

In this study, multicomponent mass diffusion models, namely the Stefan-Maxwell model (SMM), the Dusty Gas model (DGM) and the Binary Friction model (BFM) have been compared in terms of their predictive capabilities of the concentration polarization of an anode supported solid oxide fuel cell (SOFC) anode. The results show that other than the pore diameter, current density and concentration of reactants, which have a high importance in concentration polarization predictions, the tortuosity (or porosity/tortuosity) term, has a substantial effect on the model predictions. Contrary to the previous discussions in the literature, for the fitted value of tortuosities, SMM and DGM predictions are similar, even for an average pore radius as small as 2.6e-07 and current density as high as 1.5 A cm{sup -2}. Also it is shown that the BFM predictions are similar to DGM for the case investigated in this study. Moreover, in this study, the effect of the pressure gradient term in the DGM and the BFM has been investigated by including and excluding this term from the model equations. It is shown that for the case investigated and model assumptions used in this study, the terms including the pressure coefficient have an insignificant effect on the predictions of both DGM and BFM and therefore they can be neglected. (author)

Determination of element concentrations in biological reference materials by solid sampling and other analytical methods

International Nuclear Information System (INIS)

Schauenburg, H.; Weigert, P.

1992-01-01

Using solid sampling with graphite furnace atomic absorption spectrometry (GFAAS), values for cadmium, copper, lead and zinc in six biological reference materials were obtained from up to four laboratories participating in three collaborative studies. These results are compared with those obtained with other methods used in routine analysis from laboratories of official food control. Under certain conditions solid sampling with GFAAS seems to be suitable for routine analysis as well as conventional methods. (orig.)

Broad-band conductivity and dielectric spectroscopy of composites of multiwalled carbon nanotubes and poly(ethylene terephthalate) around their low percolation threshold

Czech Academy of Sciences Publication Activity Database

Nuzhnyy, Dmitry; Savinov, Maxim; Bovtun, Viktor; Kempa, Martin; Petzelt, Jan; Mayoral, B.; McNally, T.

2013-01-01

Roč. 24, č. 5 (2013), "055707-1"-"055707-9" ISSN 0957-4484 R&D Projects: GA ČR GAP204/12/0232; GA MŠk LD12025 Institutional support: RVO:68378271 Keywords : THz and dielectric spectroscopy * multiwalled carbon nanotubes * electrical percolation threshold * fluctuation-induced tunneling conductivity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.672, year: 2013 http://iopscience.iop.org/0957-4484/24/5/055707/

Compositional threshold for Nuclear Waste Glass Durability

International Nuclear Information System (INIS)

Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

2013-01-01

Within the composition space of glasses, a distinct threshold appears to exist that separates 'good' glasses, i.e., those which are sufficiently durable, from 'bad' glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region

Concentration and sources of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in surface soil near a municipal solid waste (MSW) landfill.

Science.gov (United States)

Melnyk, A; Dettlaff, A; Kuklińska, K; Namieśnik, J; Wolska, L

2015-10-15

Due to a continuous demand of land for infrastructural and residential development there is a public concern about the condition of surface soil near municipal solid waste landfills. A total of 12 surface (0-20 cm) soil samples from a territory near a landfill were collected and the concentration of 16 PAHs and 7 PCB congeners were investigated in these samples. Limits of detection were in the range of 0.038-1.2 μg/kg for PAHs and 0.025-0.041 μg/kg for PCBs. The total concentration of ∑ PAHs ranged from 892 to 3514 μg/kg with a mean of 1974 μg/kg. The total concentration of ∑ PCBs ranged from 2.5 to 12 μg/kg with a mean of 4.5 μg/kg. Data analyses allowed to state that the PAHs in surface soils near a landfill were principally from pyrogenic sources. Due to air transport, PAHs forming at the landfill are transported outside the landfill. PCB origin is not connected with the landfill. Aroclor 1242 can be the source of PCBs in several samples. Copyright © 2015. Published by Elsevier B.V.

Optimizing Systems of Threshold Detection Sensors

National Research Council Canada - National Science Library

Banschbach, David C

2008-01-01

.... Below the threshold all signals are ignored. We develop a mathematical model for setting individual sensor thresholds to obtain optimal probability of detecting a significant event, given a limit on the total number of false positives allowed...

Exact Covariance Thresholding into Connected Components for Large-Scale Graphical Lasso.

Science.gov (United States)

Mazumder, Rahul; Hastie, Trevor

2012-03-01

We consider the sparse inverse covariance regularization problem or graphical lasso with regularization parameter λ. Suppose the sample covariance graph formed by thresholding the entries of the sample covariance matrix at λ is decomposed into connected components. We show that the vertex-partition induced by the connected components of the thresholded sample covariance graph (at λ) is exactly equal to that induced by the connected components of the estimated concentration graph, obtained by solving the graphical lasso problem for the same λ. This characterizes a very interesting property of a path of graphical lasso solutions. Furthermore, this simple rule, when used as a wrapper around existing algorithms for the graphical lasso, leads to enormous performance gains. For a range of values of λ, our proposal splits a large graphical lasso problem into smaller tractable problems, making it possible to solve an otherwise infeasible large-scale problem. We illustrate the graceful scalability of our proposal via synthetic and real-life microarray examples.

Thresholds in the response of free-floating plant abundance to variation in hydraulic connectivity, nutrients, and macrophyte abundance in a large floodplain river

Science.gov (United States)

Giblin, Shawn M.; Houser, Jeffrey N.; Sullivan, John F.; Langrehr, H.A.; Rogala, James T.; Campbell, Benjamin D.

2014-01-01

Duckweed and other free-floating plants (FFP) can form dense surface mats that affect ecosystem condition and processes, and can impair public use of aquatic resources. FFP obtain their nutrients from the water column, and the formation of dense FFP mats can be a consequence and indicator of river eutrophication. We conducted two complementary surveys of diverse aquatic areas of the Upper Mississippi River as an in situ approach for estimating thresholds in the response of FFP abundance to nutrient concentration and physical conditions in a large, floodplain river. Local regression analysis was used to estimate thresholds in the relations between FFP abundance and phosphorus (P) concentration (0.167 mg l−1L), nitrogen (N) concentration (0.808 mg l−1), water velocity (0.095 m s−1), and aquatic macrophyte abundance (65 % cover). FFP tissue concentrations suggested P limitation was more likely in spring, N limitation was more likely in late summer, and N limitation was most likely in backwaters with minimal hydraulic connection to the channel. The thresholds estimated here, along with observed patterns in nutrient limitation, provide river scientists and managers with criteria to consider when attempting to modify FFP abundance in off-channel areas of large river systems.

Identifying Threshold Concepts for Information Literacy: A Delphi Study

Directory of Open Access Journals (Sweden)

Lori Townsend

2016-06-01

Full Text Available This study used the Delphi method to engage expert practitioners on the topic of threshold concepts for information literacy. A panel of experts considered two questions. First, is the threshold concept approach useful for information literacy instruction? The panel unanimously agreed that the threshold concept approach holds potential for information literacy instruction. Second, what are the threshold concepts for information literacy instruction? The panel proposed and discussed over fifty potential threshold concepts, finally settling on six information literacy threshold concepts.

Sample Results from MCU Solids Outage

Energy Technology Data Exchange (ETDEWEB)

Peters, T.; Washington, A.; Oji, L.; Coleman, C.; Poirier, M.

2014-09-22

Savannah River National Laboratory (SRNL) has received several solid and liquid samples from MCU in an effort to understand and recover from the system outage starting on April 6, 2014. SRNL concludes that the presence of solids in the Salt Solution Feed Tank (SSFT) is the likely root cause for the outage, based upon the following discoveries: A solids sample from the extraction contactor #1 proved to be mostly sodium oxalate; A solids sample from the scrub contactor#1 proved to be mostly sodium oxalate; A solids sample from the Salt Solution Feed Tank (SSFT) proved to be mostly sodium oxalate; An archived sample from Tank 49H taken last year was shown to contain a fine precipitate of sodium oxalate; A solids sample from ; A liquid sample from the SSFT was shown to have elevated levels of oxalate anion compared to the expected concentration in the feed. Visual inspection of the SSFT indicated the presence of precipitated or transferred solids, which were likely also in the Salt Solution Receipt Tank (SSRT). The presence of the solids coupled with agitation performed to maintain feed temperature resulted in oxalate solids migration through the MCU system and caused hydraulic issues that resulted in unplanned phase carryover from the extraction into the scrub, and ultimately the strip contactors. Not only did this carryover result in the Strip Effluent (SE) being pushed out of waste acceptance specification, but it resulted in the deposition of solids into several of the contactors. At the same time, extensive deposits of aluminosilicates were found in the drain tube in the extraction contactor #1. However it is not known at this time how the aluminosilicate solids are related to the oxalate solids. The solids were successfully cleaned out of the MCU system. However, future consideration must be given to the exclusion of oxalate solids into the MCU system. There were 53 recommendations for improving operations recently identified. Some additional considerations or

Measurement of trimethylamine concentration and evaluation of pig meat natural quality by a spectrophotometric method

Directory of Open Access Journals (Sweden)

Mohammod Abdul HAMID,Xi WANG,Xiangdong DING,Chuduan WANG,Xingbo ZHAO

2014-09-01

Full Text Available Pig meat off-flavor is attributed to trimethylamine (TMA concentration, and it is considered as the precursor of the fishy off-flavor problems. In this study, TMA concentrations in pig meat were determined, and the interactions with breed and gender effects were discussed. In addition, the TMA threshold for meat off-flavor and pig meat natural quality was measured in relation to meat storage and movement, and the influential factors including the pig breed and storage time were discussed. The results indicated positive effects on the precursor of the fishy off-flavor and the TMA threshold. Native breeds were found to have lower TMA concentrations than European breeds (P<0.01, and females and castrated males had significantly lower TMA concentration than males (P<0.01, The threshold concentration of TMA when meat was classed as off-flavored was 25 μg·g-1, and this occurred after 35–38 h of storage. The natural qualities, such as appearance, flavor, color and overall acceptable scores declined significantly after 4 days in storage (P<0.01. It is concluded that pig meat off-flavor, breed and gender were essential factors affecting flavor for meat breeding programs, and storage time is important for pig meat natural quality.

A population study of urine glycerol concentrations in elite athletes competing in North America.

Science.gov (United States)

Kelly, Brian N; Madsen, Myke; Sharpe, Ken; Nair, Vinod; Eichner, Daniel

2013-01-01

Glycerol is an endogenous substance that is on the World Anti-Doping Agency's list of prohibited threshold substances due to its potential use as a plasma volume expansion agent. The WADA has set the threshold for urine glycerol, including measurement uncertainty, at 1.3 mg/mL. Glycerol in circulation largely comes from metabolism of triglycerides in order to meet energy requirements and when the renal threshold is eclipsed, glycerol is excreted into urine. In part due to ethnic differences in postprandial triglyceride concentrations, we investigated urine glycerol concentrations in a population of elite athletes competing in North America and compared the results to those of athletes competing in Europe. 959 urine samples from elite athletes competing in North America collected for anti-doping purposes were analyzed for urine glycerol concentrations by a gas chromatography mass-spectrometry method. Samples were divided into groups according to: Timing (in- or out-of-competition), Class (strength, game, or endurance sports) and Gender. 333 (34.7%) samples had undetectable amounts of glycerol (sport classes. Copyright © 2013 John Wiley & Sons, Ltd.

Multiuser switched diversity scheduling systems with per-user threshold

KAUST Repository

Nam, Haewoon

2010-05-01

A multiuser switched diversity scheduling scheme with per-user feedback threshold is proposed and analyzed in this paper. The conventional multiuser switched diversity scheduling scheme uses a single feedback threshold for every user, where the threshold is a function of the average signal-to-noise ratios (SNRs) of the users as well as the number of users involved in the scheduling process. The proposed scheme, however, constructs a sequence of feedback thresholds instead of a single feedback threshold such that each user compares its channel quality with the corresponding feedback threshold in the sequence. Numerical and simulation results show that thanks to the flexibility of threshold selection, where a potentially different threshold can be used for each user, the proposed scheme provides a higher system capacity than that for the conventional scheme. © 2006 IEEE.

Thermoacoustics of solids: A pathway to solid state engines and refrigerators

Science.gov (United States)

Hao, Haitian; Scalo, Carlo; Sen, Mihir; Semperlotti, Fabio

2018-01-01

Thermoacoustic oscillations have been one of the most exciting discoveries of the physics of fluids in the 19th century. Since its inception, scientists have formulated a comprehensive theoretical explanation of the basic phenomenon which has later found several practical applications to engineering devices. To date, all studies have concentrated on the thermoacoustics of fluid media where this fascinating mechanism was exclusively believed to exist. Our study shows theoretical and numerical evidence of the existence of thermoacoustic instabilities in solid media. Although the underlying physical mechanism exhibits some interesting similarities with its counterpart in fluids, the theoretical framework highlights relevant differences that have important implications on the ability to trigger and sustain the thermoacoustic response. This mechanism could pave the way to the development of highly robust and reliable solid-state thermoacoustic engines and refrigerators.

Study on the solid state track detector with controllable detection sensitivity

International Nuclear Information System (INIS)

Tsuruta, Takao; Koguchi, Yasuhiro; Ashida, Taro

2003-01-01

In a study aimed at the determination of threshold vale for detection of heavy ions, several types of copolymers of DAP and CR-39 have been irradiated with several kinds of ions at the middle-energy port and bio-port of National Institute of Radiological Sciences-Heavy Ion Medical Accelerator in Chiba (NIRS-HIMAC). As a results, the thresholds are 55, 99, 124 and 224 keV/μm in water for 50%, 60%, 70% and 80% of DAP concentration, respectively. (author)

InAs/GaAs quantum dot lasers with InGaP cladding layer grown by solid-source molecular-beam epitaxy

International Nuclear Information System (INIS)

Yeh, N.-T.; Liu, W.-S.; Chen, S.-H.; Chiu, P.-C.; Chyi, J.-I.

2002-01-01

This letter presents the lasing properties of InAs/GaAs quantum dot lasers with InGaP cladding layers grown by solid-source molecular-beam epitaxy. These Al-free lasers exhibit a threshold current density of 138 A/cm 2 , an internal loss of 1.35 cm -1 , and an internal quantum efficiency of 31% at room temperature. At a low temperature, a very high characteristic temperature of 425 K and very low threshold current density of 30 A/cm 2 are measured

A portable concentrator for processing plutonium containing solutions

International Nuclear Information System (INIS)

Chamberlain, D.B.; Conner, C.; Chen, L.

1995-01-01

This report describes a horizontal, compact agitated-film concentrator called a Rototherm, manufactured by Artisan Industries, Inc. which can be used to process aqueous solutions of radioactive wastes containing plutonium. The unit is designed to concentrate liquid streams to a high-solid content slurry

Tratamento anaeróbio de resíduos sólidos orgânicos com alta e baixa concentração de sólidos Anaerobic treatment of organic solid waste with high and low concentrations of solids

Directory of Open Access Journals (Sweden)

Valderi D. Leite

2009-04-01

Full Text Available A finalidade principal deste trabalho foi estudar o tratamento anaeróbio de resíduos sólidos orgânicos com alta e baixa concentração de sólidos. O sistema experimental se compunha de dois reatores com capacidade unitária de 2.200 L, enquanto o substrato utilizado era composto de resíduos sólidos vegetais e lodo de esgotos sanitários, sendo um dos reatores alimentado com substrato contendo 20% de sólidos totais (80% de umidade e o outro com apenas 5% de sólidos totais (95% de umidade. Verificou-se, quando da utilização de substrato contendo 5% (percentagem em peso de sólidos totais, que o tempo de retenção de sólidos requerido para que fossem alcançados 80% de redução da massa de DQO aplicada, foi de 90 dias, propiciando uma taxa de produção de gás metano de 0,25 Nm³ CH4 kg-1 DQO Aplicada. Com relação ao substrato contendo 20% de sólidos totais, o tempo de retenção de sólidos requerido para bioestabilizar 80% da massa de DQO aplicada, foi de 270 dias, com taxa de produção de gás metano de 0,10 Nm³ CH4 kg-1 DQO Aplicada.In this study the anaerobic treatment of organic solid waste with high and low concentrations of solids was studied. The experimental system comprised of two reactors, with unitary capacity of 2,200 L, while the used substrate was composed of solid vegetable waste and sludge. One of the reactors was loaded with substrate containing 20% of total solids and the other with only 5% of total solids on weight basis. It was verified that, for the substrate containing 5% of total solids, the retention time of solids required for 80% reduction of the applied COD mass was 90 days, during which the methane gas production rate was of 0.25 Nm³ kg-1 COD Applied; whereas in the substrate containing 20% of total solids, the retention time of solids required for biostabilization of 80% of the mass of applied COD was 270 days, with a methane gas production rate of 0.1 Nm³ CH4 kg-1 COD Applied.

Indigenous microbial capability in solid manure residues to start-up solid-phase anaerobic digesters.

Science.gov (United States)

Yap, S D; Astals, S; Jensen, P D; Batstone, D J; Tait, S

2017-06-01

Batch solid-phase anaerobic digestion is a technology for sustainable on-farm treatment of solid residues, but is an emerging technology that is yet to be optimised with respect to start-up and inoculation. In the present study, spent bedding from two piggeries (site A and B) were batch digested at total solids (TS) concentration of 5, 10 and 20% at mesophilic (37°C) and thermophilic (55°C) temperatures, without adding an external inoculum. The results showed that the indigenous microbial community present in spent bedding was able to recover the full methane potential of the bedding (140±5 and 227±6L CH 4 kgVS fed -1 for site A and B, respectively), but longer treatment times were required than for digestion with an added external inoculum. Nonetheless, at high solid loadings (i.e. TS level>10%), the digestion performance was affected by chemical inhibition due to ammonia and/or humic acid. Thermophilic temperatures did not influence digestion performance but did increase start-up failure risk. Further, inoculation of residues from the batch digestion to subsequent batch enhanced start-up and achieved full methane potential recovery of the bedding. Inoculation with liquid residue (leachate) was preferred over a solid residue, to preserve treatment capacity for fresh substrate. Overall, the study highlighted that indigenous microbial community in the solid manure residue was capable of recovering full methane potential and that solid-phase digestion was ultimately limited by chemical inhibition rather than lack of suitable microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pain thresholds, supra-threshold pain and lidocaine sensitivity in patients with erythromelalgia, including the I848Tmutation in NaV 1.7.

Science.gov (United States)

Helås, T; Sagafos, D; Kleggetveit, I P; Quiding, H; Jönsson, B; Segerdahl, M; Zhang, Z; Salter, H; Schmelz, M; Jørum, E

2017-09-01

Nociceptive thresholds and supra-threshold pain ratings as well as their reduction upon local injection with lidocaine were compared between healthy subjects and patients with erythromelalgia (EM). Lidocaine (0.25, 0.50, 1.0 or 10 mg/mL) or placebo (saline) was injected intradermally in non-painful areas of the lower arm, in a randomized, double-blind manner, to test the effect on dynamic and static mechanical sensitivity, mechanical pain sensitivity, thermal thresholds and supra-threshold heat pain sensitivity. Heat pain thresholds and pain ratings to supra-threshold heat stimulation did not differ between EM-patients (n = 27) and controls (n = 25), neither did the dose-response curves for lidocaine. Only the subgroup of EM-patients with mutations in sodium channel subunits Na V 1.7, 1.8 or 1.9 (n = 8) had increased lidocaine sensitivity for supra-threshold heat stimuli, contrasting lower sensitivity to strong mechanical stimuli. This pattern was particularly clear in the two patients carrying the Na V 1.7 I848T mutations in whom lidocaine's hyperalgesic effect on mechanical pain sensitivity contrasted more effective heat analgesia. Heat pain thresholds are not sensitized in EM patients, even in those with gain-of-function mutations in Na V 1.7. Differential lidocaine sensitivity was overt only for noxious stimuli in the supra-threshold range suggesting that sensitized supra-threshold encoding is important for the clinical pain phenotype in EM in addition to lower activation threshold. Intracutaneous lidocaine dose-dependently blocked nociceptive sensations, but we did not identify EM patients with particular high lidocaine sensitivity that could have provided valuable therapeutic guidance. Acute pain thresholds and supra-threshold heat pain in controls and patients with erythromelalgia do not differ and have the same lidocaine sensitivity. Acute heat pain thresholds even in EM patients with the Na V 1.7 I848T mutation are normal and only nociceptor

Modelling dewatering behaviour through an understanding of solids formation processes. Part II--solids separation considerations.

Science.gov (United States)

Dustan, A C; Cohen, B; Petrie, J G

2005-05-30

An understanding of the mechanisms which control solids formation can provide information on the characteristics of the solids which are formed. The nature of the solids formed in turn impacts on dewatering behaviour. The 'upstream' solids formation determines a set of suspension characteristics: solids concentration, particle size distribution, solution ionic strength and electrostatic surface potential. These characteristics together define the suspension's rheological properties. However, the complicated interdependence of these has precluded the prediction of suspension rheology from such a fundamental description of suspension characteristics. Recent shear yield stress models, applied in this study to compressive yield, significantly reduce the empiricism required for the description of compressive rheology. Suspension compressibility and permeability uniquely define the dewatering behaviour, described in terms of settling, filtration and mechanical expression. These modes of dewatering may be described in terms of the same fundamental suspension mechanics model. In this way, it is possible to link dynamically the processes of solids formation and dewatering of the resultant suspension. This, ultimately, opens the door to improved operability of these processes. In part I of this paper we introduced an integrated system model for solids formation and dewatering. This model was demonstrated for the upstream processes using experimental data. In this current paper models of colloidal interactions and dewatering are presented and compared to experimental results from batch filtration tests. A novel approach to predicting suspension compressibility and permeability using a single test configuration is presented and tested.

When do price thresholds matter in retail categories?

OpenAIRE

Pauwels, Koen; Srinivasan, Shuba; Franses, Philip Hans

2007-01-01

textabstractMarketing literature has long recognized that brand price elasticity need not be monotonic and symmetric, but has yet to provide generalizable market-level insights on threshold-based price elasticity, asymmetric thresholds, and the sign and magnitude of elasticity transitions. This paper introduces smooth transition regression models to study threshold-based price elasticity of the top 4 brands across 20 fast-moving consumer good categories. Threshold-based price elasticity is fo...

High-order above-threshold dissociation of molecules

Science.gov (United States)

Lu, Peifen; Wang, Junping; Li, Hui; Lin, Kang; Gong, Xiaochun; Song, Qiying; Ji, Qinying; Zhang, Wenbin; Ma, Junyang; Li, Hanxiao; Zeng, Heping; He, Feng; Wu, Jian

2018-03-01

Electrons bound to atoms or molecules can simultaneously absorb multiple photons via the above-threshold ionization featured with discrete peaks in the photoelectron spectrum on account of the quantized nature of the light energy. Analogously, the above-threshold dissociation of molecules has been proposed to address the multiple-photon energy deposition in the nuclei of molecules. In this case, nuclear energy spectra consisting of photon-energy spaced peaks exceeding the binding energy of the molecular bond are predicted. Although the observation of such phenomena is difficult, this scenario is nevertheless logical and is based on the fundamental laws. Here, we report conclusive experimental observation of high-order above-threshold dissociation of H2 in strong laser fields where the tunneling-ionized electron transfers the absorbed multiphoton energy, which is above the ionization threshold to the nuclei via the field-driven inelastic rescattering. Our results provide an unambiguous evidence that the electron and nuclei of a molecule as a whole absorb multiple photons, and thus above-threshold ionization and above-threshold dissociation must appear simultaneously, which is the cornerstone of the nowadays strong-field molecular physics.

Thresholds in Xeric Hydrology and Biogeochemistry

Science.gov (United States)

Meixner, T.; Brooks, P. D.; Simpson, S. C.; Soto, C. D.; Yuan, F.; Turner, D.; Richter, H.

2011-12-01

Due to water limitation, thresholds in hydrologic and biogeochemical processes are common in arid and semi-arid systems. Some of these thresholds such as those focused on rainfall runoff relationships have been well studied. However to gain a full picture of the role that thresholds play in driving the hydrology and biogeochemistry of xeric systems a full view of the entire array of processes at work is needed. Here a walk through the landscape of xeric systems will be conducted illustrating the powerful role of hydrologic thresholds on xeric system biogeochemistry. To understand xeric hydro-biogeochemistry two key ideas need to be focused on. First, it is important to start from a framework of reaction and transport. Second an understanding of the temporal and spatial components of thresholds that have a large impact on hydrologic and biogeochemical fluxes needs to be offered. In the uplands themselves episodic rewetting and drying of soils permits accelerated biogeochemical processing but also more gradual drainage of water through the subsurface than expected in simple conceptions of biogeochemical processes. Hydrologic thresholds (water content above hygroscopic) results in a stop start nutrient spiral of material across the landscape since runoff connecting uplands to xeric perennial riparian is episodic and often only transports materials a short distance (100's of m). This episodic movement results in important and counter-intuitive nutrient inputs to riparian zones but also significant processing and uptake of nutrients. The floods that transport these biogeochemicals also result in significant input to riparian groundwater and may be key to sustaining these critical ecosystems. Importantly the flood driven recharge process itself is a threshold process dependent on flood characteristics (floods greater than 100 cubic meters per second) and antecedent conditions (losing to near neutral gradients). Floods also appear to influence where arid and semi

Electrosprayed core–shell solid dispersions of acyclovir fabricated using an epoxy-coated concentric spray head

Science.gov (United States)

Liu, Zhe-Peng; Cui, Lei; Yu, Deng-Guang; Zhao, Zhuan-Xia; Chen, Lan

2014-01-01

A novel structural solid dispersion (SD) taking the form of core–shell microparticles for poorly water-soluble drugs is reported for the first time. Using polyvinylpyrrolidone (PVP) as a hydrophilic polymer matrix, the SDs were fabricated using coaxial electrospraying (characterized by an epoxy-coated concentric spray head), although the core fluids were unprocessable using one-fluid electrospraying. Through manipulating the flow rates of the core drug-loaded solutions, two types of core–shell microparticles with tunable drug contents were prepared. They had average diameters of 1.36±0.67 and 1.74±0.58 μm, and were essentially a combination of nanocomposites with the active ingredient acyclovir (ACY) distributed in the inner core, and the sweeter sucralose and transmembrane enhancer sodium dodecyl sulfate localized in the outer shell. Differential scanning calorimetry and X-ray diffraction results demonstrated that ACY, sodium dodecyl sulfate, and sucralose were well distributed in the PVP matrix in an amorphous state because of favorable second-order interactions. In vitro dissolution and permeation studies showed that the core–shell microparticle SDs rapidly freed ACY within 1 minute and promoted nearly eightfold increases in permeation rate across the sublingual mucosa compared with raw ACY powders. PMID:24790437

Determinants of Change in the Cost-effectiveness Threshold.

Science.gov (United States)

Paulden, Mike; O'Mahony, James; McCabe, Christopher

2017-02-01

The cost-effectiveness threshold in health care systems with a constrained budget should be determined by the cost-effectiveness of displacing health care services to fund new interventions. Using comparative statics, we review some potential determinants of the threshold, including the budget for health care, the demand for existing health care interventions, the technical efficiency of existing interventions, and the development of new health technologies. We consider the anticipated direction of impact that would affect the threshold following a change in each of these determinants. Where the health care system is technically efficient, an increase in the health care budget unambiguously raises the threshold, whereas an increase in the demand for existing, non-marginal health interventions unambiguously lowers the threshold. Improvements in the technical efficiency of existing interventions may raise or lower the threshold, depending on the cause of the improvement in efficiency, whether the intervention is already funded, and, if so, whether it is marginal. New technologies may also raise or lower the threshold, depending on whether the new technology is a substitute for an existing technology and, again, whether the existing technology is marginal. Our analysis permits health economists and decision makers to assess if and in what direction the threshold may change over time. This matters, as threshold changes impact the cost-effectiveness of interventions that require decisions now but have costs and effects that fall in future periods.

Low heat pain thresholds in migraineurs between attacks.

Science.gov (United States)

Schwedt, Todd J; Zuniga, Leslie; Chong, Catherine D

2015-06-01

Between attacks, migraine is associated with hypersensitivities to sensory stimuli. The objective of this study was to investigate hypersensitivity to pain in migraineurs between attacks. Cutaneous heat pain thresholds were measured in 112 migraineurs, migraine free for ≥ 48 hours, and 75 healthy controls. Pain thresholds at the head and at the arm were compared between migraineurs and controls using two-tailed t-tests. Among migraineurs, correlations between heat pain thresholds and headache frequency, allodynia symptom severity, and time interval until next headache were calculated. Migraineurs had lower pain thresholds than controls at the head (43.9 ℃ ± 3.2 ℃ vs. 45.1 ℃ ± 3.0 ℃, p = 0.015) and arm (43.2 ℃ ± 3.4 ℃ vs. 44.8 ℃ ± 3.3 ℃, p pain thresholds and headache frequency or allodynia symptom severity. For the 41 migraineurs for whom time to next headache was known, there were positive correlations between time to next headache and pain thresholds at the head (r = 0.352, p = 0.024) and arm (r = 0.312, p = 0.047). This study provides evidence that migraineurs have low heat pain thresholds between migraine attacks. Mechanisms underlying these lower pain thresholds could also predispose migraineurs to their next migraine attack, a hypothesis supported by finding positive correlations between pain thresholds and time to next migraine attack. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Freeze concentration of lime juice

Directory of Open Access Journals (Sweden)

Ampawan Tansakul

2008-11-01

Full Text Available The main objective of this research was to study the effects of processing conditions, i.e. cooling medium temperature (-6, -12 and -18C and scraper blade rotational speed (50, 100 and 150 rpm on the freeze concentration of lime juice. The initial soluble solid content of lime juice was 7.6 Brix. Results showed that soluble solid content of lime juice increased as cooling medium temperature decreased while scraper blade rotational speed increased. It was also found that the processing condition with -18˚C cooling medium temperature and 150 rpm rotational speed of the scraper blade was the best among all studied conditions, although the loss of the soluble solids with ice crystals during ice separation was relatively high at 35%.

Some considerations regarding the creep crack growth threshold

International Nuclear Information System (INIS)

Thouless, M.D.; Evans, A.G.

1984-01-01

The preceding analysis reveals that the existence of a threshold determined by the sintering stress does not influence the post threshold crack velocity. Considerations of the sintering stress can thus be conveniently excluded from analysis of the post threshold crack velocity. The presence of a crack growth threshold has been predicted, based on the existence of cavity nucleation controlled crack growth. A preliminary analysis of cavity nucleation rates within the damage zone reveals that this threshold is relatively abrupt, in accord with experimental observations. Consequently, at stress intensities below K /SUB th/ growth becomes nucleation limited and crack blunting occurs in preference to crack growth

Lead toxicity thresholds in 17 Chinese soils based on substrate-induced nitrification assay.

Science.gov (United States)

Li, Ji; Huang, Yizong; Hu, Ying; Jin, Shulan; Bao, Qiongli; Wang, Fei; Xiang, Meng; Xie, Huiting

2016-06-01

The influence of soil properties on toxicity threshold values for Pb toward soil microbial processes is poorly recognized. The impact of leaching on the Pb threshold has not been assessed systematically. Lead toxicity was screened in 17 Chinese soils using a substrate-induced nitrification (SIN) assay under both leached and unleached conditions. The effective concentration of added Pb causing 50% inhibition (EC50) ranged from 185 to >2515mg/kg soil for leached soil and 130 to >2490mg/kg soil for unleached soil. These results represented >13- and >19-fold variations among leached and unleached soils, respectively. Leaching significantly reduced Pb toxicity for 70% of both alkaline and acidic soils tested, with an average leaching factor of 3.0. Soil pH and CEC were the two most useful predictors of Pb toxicity in soils, explaining over 90% of variance in the unleached EC50 value. The relationships established in the present study predicted Pb toxicity within a factor of two of measured values. These relationships between Pb toxicity and soil properties could be used to establish site-specific guidance on Pb toxicity thresholds. Copyright © 2016. Published by Elsevier B.V.

Lactate threshold by muscle electrical impedance in professional rowers

Science.gov (United States)

Jotta, B.; Coutinho, A. B. B.; Pino, A. V.; Souza, M. N.

2017-04-01

Lactate threshold (LT) is one of the physiological parameters usually used in rowing sport training prescription because it indicates the transitions from aerobic to anaerobic metabolism. Assessment of LT is classically based on a series of values of blood lactate concentrations obtained during progressive exercise tests and thus has an invasive aspect. The feasibility of noninvasive LT estimative through bioelectrical impedance spectroscopy (BIS) data collected in thigh muscles during rowing ergometer exercise tests was investigated. Nineteen professional rowers, age 19 (mean) ± 4.8 (standard deviation) yr, height 187.3 ± 6.6 cm, body mass 83 ± 7.7 kg, and training experience of 7 ± 4 yr, were evaluated in a rowing ergometer progressive test with paired measures of blood lactate concentration and BIS in thigh muscles. Bioelectrical impedance data were obtained by using a bipolar method of spectroscopy based on the current response to a voltage step. An electrical model was used to interpret BIS data and to derive parameters that were investigated to estimate LT noninvasively. From the serial blood lactate measurements, LT was also determined through Dmax method (LTDmax). The zero crossing of the second derivative of kinetic of the capacitance electrode (Ce), one of the BIS parameters, was used to estimate LT. The agreement between the LT estimates through BIS (LTBIS) and through Dmax method (LTDmax) was evaluated using Bland-Altman plots, leading to a mean difference between the estimates of just 0.07 W and a Pearson correlation coefficient r = 0.85. This result supports the utilization of the proposed method based on BIS parameters for estimating noninvasively the lactate threshold in rowing.

Pulse Jet Mixing Tests With Noncohesive Solids

Energy Technology Data Exchange (ETDEWEB)

Meyer, Perry A.; Bamberger, Judith A.; Enderlin, Carl W.; Fort, James A.; Wells, Beric E.; Sundaram, S. K.; Scott, Paul A.; Minette, Michael J.; Smith, Gary L.; Burns, Carolyn A.; Greenwood, Margaret S.; Morgen, Gerald P.; Baer, Ellen BK; Snyder, Sandra F.; White, Michael; Piepel, Gregory F.; Amidan, Brett G.; Heredia-Langner, Alejandro; Bailey, Sharon A.; Bower, John C.; Denslow, Kayte M.; Eakin, David E.; Elmore, Monte R.; Gauglitz, Phillip A.; Guzman, Anthony D.; Hatchell, Brian K.; Hopkins, Derek F.; Hurley, David E.; Johnson, Michael D.; Kirihara, Leslie J.; Lawler, Bruce D.; Loveland, Jesse S.; Mullen, O Dennis; Pekour, Mikhail S.; Peters, Timothy J.; Robinson, Peter J.; Russcher, Michael S.; Sande, Susan; Santoso, Christian; Shoemaker, Steven V.; Silva, Steve M.; Smith, Devin E.; Su, Yin-Fong; Toth, James J.; Wiberg, John D.; Yu, Xiao-Ying; Zuljevic, Nino

2009-05-11

This report summarizes results from pulse jet mixing (PJM) tests with noncohesive solids in Newtonian liquid conducted during FY 2007 and 2008 to support the design of mixing systems for the Hanford Waste Treatment and Immobilization Plant (WTP). Tests were conducted at three geometric scales using noncohesive simulants. The test data were used to independently develop mixing models that can be used to predict full-scale WTP vessel performance and to rate current WTP mixing system designs against two specific performance requirements. One requirement is to ensure that all solids have been disturbed during the mixing action, which is important to release gas from the solids. The second requirement is to maintain a suspended solids concentration below 20 weight percent at the pump inlet. The models predict the height to which solids will be lifted by the PJM action, and the minimum velocity needed to ensure all solids have been lifted from the floor. From the cloud height estimate we can calculate the concentration of solids at the pump inlet. The velocity needed to lift the solids is slightly more demanding than "disturbing" the solids, and is used as a surrogate for this metric. We applied the models to assess WTP mixing vessel performance with respect to the two perform¬ance requirements. Each mixing vessel was evaluated against these two criteria for two defined waste conditions. One of the wastes was defined by design limits and one was derived from Hanford waste characterization reports. The assessment predicts that three vessel types will satisfy the design criteria for all conditions evaluated. Seven vessel types will not satisfy the performance criteria used for any of the conditions evaluated. The remaining three vessel types provide varying assessments when the different particle characteristics are evaluated. The assessment predicts that three vessel types will satisfy the design criteria for all conditions evaluated. Seven vessel types will not satisfy

When Do Price Thresholds Matter in Retail Categories?

OpenAIRE

Koen Pauwels; Shuba Srinivasan; Philip Hans Franses

2007-01-01

Marketing literature has long recognized that brand price elasticity need not be monotonic and symmetric, but has yet to provide generalizable market-level insights on threshold-based price elasticity, asymmetric thresholds, and the sign and magnitude of elasticity transitions. This paper introduces smooth transition regression models to study threshold-based price elasticity of the top 4 brands across 20 fast-moving consumer good categories. Threshold-based price elasticity is found for 76% ...

Estimating the Threshold Level of Inflation for Thailand

OpenAIRE

Jiranyakul, Komain

2017-01-01

Abstract. This paper analyzes the relationship between inflation and economic growth in Thailand using annual dataset during 1990 and 2015. The threshold model is estimated for different levels of threshold inflation rate. The results suggest that the threshold level of inflation above which inflation significantly slow growth is estimated at 3 percent. The negative relationship between inflation and growth is apparent above this threshold level of inflation. In other words, the inflation rat...

Critical conducting networks in disordered solids: ac universality from topological arguments

DEFF Research Database (Denmark)

Milovanov, A.V.; Juul Rasmussen, Jens

2001-01-01

This paper advocates an unconventional description of charge transport processes in disordered solids, which brings together the ideas of fractal geometry, percolation theory, and topology of manifolds. We demonstrate that the basic features of ac conductivity in disordered materials as seen...... in various experiments are reproduced with remarkable accuracy by the conduction properties of percolating fractal networks near the threshold of percolation. The universal character of ac conductivity in three embedding dimensions is discussed in connection with the available experimental data. An important...

Numerical simulation of the gas-solid flow in a square circulating fluidized bed with secondary air injection

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhengyang [Harbin Institute of Technology, Harbin (China). Post-doctor Station of Civil Engineering; Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Sun, Shaozeng; Zhao, Ningbo; Wu, Shaohua [Harbin Institute of Technology, Harbin (China). Combustion Engineering Research Inst.; Tan, Yufei [Harbin Institute of Technology, Harbin (China). School of Municipal and Environmental Engineering

2013-07-01

The dynamic behavior of gas-solid flow in an experimental square circulating fluidized bed setup (0.25 m x 0.25 m x 6.07 m) is predicted with numerical simulation based on the theory of Euler-Euler gas-solid two-phase flow and the kinetic theory of granular flows. The simulation includes the operation cases with secondary injection and without air-staging. The pressure drop profile, local solids concentration and particle velocity was compared with experimental results. Both simulation and experimental results show that solids concentration increases significantly below the secondary air injection ports when air-staging is adopted. Furthermore, the flow asymmetry in the solid entrance region of the bed was investigated based on the particle concentration/velocity profile. The simulation results are in agreement with the experimental results qualitatively.

Identification of threshold body burdens of metals for the protection of the aquatic ecological status using two benthic invertebrates

International Nuclear Information System (INIS)

Bervoets, Lieven; De Jonge, Maarten; Blust, Ronny

2016-01-01

In this study accumulated concentrations of As, Cd, Cr, Cu, Ni, Pb and Zn in two benthic invertebrate taxa, Chironomus sp. and Tubificidae are related to ecological responses expressed as changes in macro invertebrate communities. In addition critical body burdens were estimated above which ecological quality was always lower than a certain threshold. Data from existing studies on bioaccumulation of the metals in both taxa were combined with different biological water quality indices. For all metal-endpoint combinations threshold values could be calculated above which ecological quality was always low. Safe threshold body burdens could be estimated for both species for all metals although the data set was more extended for Chrionomus sp. with estimated threshold values being 65, 3.2, 10, 57, 6.5, 73 and 490 μg/g dw for As, Cd, Cr, Cu, Ni, Pb and Zn. This study demonstrated that metal accumulation in resistant species such as chironomids and tubificid worms have the potential to be used as predictors of ecological effects in aquatic ecosystems. However, the estimated threshold values have to be validated and supported by more lines of evidence before they can be used by regulators. - Highlights: • Chironomid larvae and Tubificid worms can be used to relate accumulated metals to ecological endpoints. • Ecological water quality, calculated with biotic indices, is always low at high accumulated metal concentrations. • Critical body burdens in chironomids and tubificds could be estimated for As, Cd, Cr, Cu, Ni, Pb and Zn. - Maximal body burdens of metals in two invertebrate species could be estimated above which ecological quality was always low.

Time-efficient multidimensional threshold tracking method

DEFF Research Database (Denmark)

Fereczkowski, Michal; Kowalewski, Borys; Dau, Torsten

2015-01-01

Traditionally, adaptive methods have been used to reduce the time it takes to estimate psychoacoustic thresholds. However, even with adaptive methods, there are many cases where the testing time is too long to be clinically feasible, particularly when estimating thresholds as a function of anothe...

CHANGES IN THE ANAEROBIC THRESHOLD IN AN ANNUAL CYCLE OF SPORT TRAINING OF YOUNG SOCCER PLAYERS

Directory of Open Access Journals (Sweden)

Robert Śliwowski

2013-04-01

Full Text Available The aim of the study was to assess changes in the anaerobic threshold of young soccer players in an annual training cycle. A group of highly trained 15-18 year old players of KKS Lech Poznań were tested. The tests included an annual training macrocycle, and its individual stages resulted from the time structure of the sports training. In order to assess the level of exercise capacities of the players, a field exercise test of increasing intensity was carried out on a soccer pitch. The test made it possible to determine the 4 millimolar lactate threshold (T LA 4 mmol · l-1 on the basis of the lactate concentration in blood [LA], to establish the threshold running speed and the threshold heart rate [HR]. The threshold running speed at the level of the 4 millimolar lactate threshold was established using the two-point form of the equation of a straight line. The obtained indicators of the threshold running speed allowed for precise establishment of effort intensity used in individual training in developing aerobic endurance. In order to test the significance of differences in mean values between four dates of tests, a non-parametric Friedman ANOVA test was used. The significance of differences between consecutive dates of tests was determined using a post-hoc Friedman ANOVA test. The tests showed significant differences in values of selected indicators determined at the anaerobic threshold in various stages of an annual training cycle of young soccer players. The most beneficial changes in terms of the threshold running speed were noted on the fourth date of tests, when the participants had the highest values of 4.01 m · s-1 for older juniors, and 3.80 m · s-1 for younger juniors. This may be indicative of effective application of an individualized programme of training loads and of good preparation of teams for competition in terms of players’ aerobic endurance.

A light-powered sub-threshold microprocessor

Energy Technology Data Exchange (ETDEWEB)

Liu Ming; Chen Hong; Zhang Chun; Li Changmeng; Wang Zhihua, E-mail: lium02@mails.tsinghua.edu.cn [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2010-11-15

This paper presents an 8-bit sub-threshold microprocessor which can be powered by an integrated photosensitive diode. With a custom designed sub-threshold standard cell library and 1 kbit sub-threshold SRAM design, the leakage power of 58 nW, dynamic power of 385 nW - 165 kHz, EDP 13 pJ/inst and the operating voltage of 350 mV are achieved. Under a light of about 150 kLux, the microprocessor can run at a rate of up to 500 kHz. The microprocessor can be used for wireless-sensor-network nodes.

New apparatus for measuring radon adsorption on solid adsorbents

International Nuclear Information System (INIS)

Hassan, N.M.; Hines, A.L.; Ghosh, T.K.; Loyalka, S.K.; Ketring, A.R.

1991-01-01

A new experimental system was designed to measure radon uptake by solid adsorbents from air or other carrier gases/vapors. The total amount of radon adsorbed corresponding to a specific gas-phase concentration was determined by simultaneously measuring the solid-phase and gas-phase concentrations. The system was used to measure radon adsorption isotherms on BPL activated carbon at 288, 298, and 308 K and on silica gel and molecular sieve 13X at 298 K. The isotherms were of type III according to Brunauer's classification. The heat of adsorption data indicated that the BPL activated carbon provided a heterogeneous surface for radon adsorption. The equilibrium data were correlated by the Freundlich equation. In this paper the possible adsorption mechanism and the use of the adsorption isotherms to measure indoor radon concentrations are discussed

A solid tissue phantom for photon migration studies

International Nuclear Information System (INIS)

Cubeddu, Rinaldo; Pifferi, Antonio; Taroni, Paola; Torricelli, Alessandro; Valentini, Gianluca

1997-01-01

A solid tissue phantom made of agar, Intralipid and black ink is described and characterized. The preparation procedure is fast and easily implemented with standard laboratory equipment. An instrumentation for time-resolved transmittance measurements was used to determine the optical properties of the phantom. The absorption and the reduced scattering coefficients are linear with the ink and Intralipid concentrations, respectively. A systematic decrease of the reduced scattering coefficient dependent on the agar content is observed, but can easily be managed. The phantom is highly homogeneous and shows good repeatability among different preparations. Moreover, agar inclusions can be easily embedded in either solid or liquid matrixes, and no artefacts are caused by the solid - solid or solid - liquid interfaces. This allows one to produce reliable and realistic inhomogeneous phantoms with known optical properties, particularly interesting for studies on optical imaging through turbid media. (author)

Threshold concepts in finance: student perspectives

Science.gov (United States)

Hoadley, Susan; Kyng, Tim; Tickle, Leonie; Wood, Leigh N.

2015-10-01

Finance threshold concepts are the essential conceptual knowledge that underpin well-developed financial capabilities and are central to the mastery of finance. In this paper we investigate threshold concepts in finance from the point of view of students, by establishing the extent to which students are aware of threshold concepts identified by finance academics. In addition, we investigate the potential of a framework of different types of knowledge to differentiate the delivery of the finance curriculum and the role of modelling in finance. Our purpose is to identify ways to improve curriculum design and delivery, leading to better student outcomes. Whilst we find that there is significant overlap between what students identify as important in finance and the threshold concepts identified by academics, much of this overlap is expressed by indirect reference to the concepts. Further, whilst different types of knowledge are apparent in the student data, there is evidence that students do not necessarily distinguish conceptual from other types of knowledge. As well as investigating the finance curriculum, the research demonstrates the use of threshold concepts to compare and contrast student and academic perceptions of a discipline and, as such, is of interest to researchers in education and other disciplines.

Forensic analysis of high explosives residues in post-blast water samples employing solid phase extraction for analyte pro-concentration

International Nuclear Information System (INIS)

Umi Kalsom Ahmad; Rajendran, Sumathy; Ling, Lee Woan

2008-01-01

Nitro aromatic, nitramine and nitrate ester compounds are a major group of high order explosive or better known as military explosives. Octahydro-1,3,5,7-tetrazocine (HMX), 1,3,5-hexahydro-1,3,5-trinitro triazine (RDX), 2,4,6-trinitro-toluene (TNT), pentaerythritol tetranitrate (PETN) and 2,4-dinitrotoluene (2,4-DNT) are secondary high explosives classified as most commonly used explosives components. There is an increasing demand for pre-concentration of these compounds in water samples as the sensitivity achieved by instrumental analytical methods for these high explosives residues are the main drawback in the application at trace levels for forensic analysis. Hence, a simple cartridge solid phase extraction (SPE) procedure was optimized as the off-line extraction and pre-concentration method to enhance the detection limit of high explosive residues using micellar electrokinetic chromatography (MEKC) and gas chromatography with electron-capture detection (GC-ECD) methods. The SPE cartridges utilized LiChrolut EN as the SPE adsorbent. By emplying pre-concentration using SPE, the detection limits of the target analytes in water sample were lowered by more than 1000 times with good percentage recovery (>87%) for MEKC method and lowered by 120 times with more than 2 % percentage recovery for GC-ECD methods. In order to test the feasibility of the developed method to real cases, post-blast water samples were analyzed. The post-blast water samples which were collected from Baling Bom training range, Ulu Kinta, Perak contained RDX and PETN in the range of 0.05 - 0.17 ppm and 0.0124 - 0.0390 ppm respectively. (author)

Two dimensional solid state NMR

International Nuclear Information System (INIS)

Kentgens, A.P.M.

1987-01-01

This thesis illustrates, by discussing some existing and newly developed 2D solid state experiments, that two-dimensional NMR of solids is a useful and important extension of NMR techniques. Chapter 1 gives an overview of spin interactions and averaging techniques important in solid state NMR. As 2D NMR is already an established technique in solutions, only the basics of two dimensional NMR are presented in chapter 2, with an emphasis on the aspects important for solid spectra. The following chapters discuss the theoretical background and applications of specific 2D solid state experiments. An application of 2D-J resolved NMR, analogous to J-resolved spectroscopy in solutions, to natural rubber is given in chapter 3. In chapter 4 the anisotropic chemical shift is mapped out against the heteronuclear dipolar interaction to obtain information about the orientation of the shielding tensor in poly-(oxymethylene). Chapter 5 concentrates on the study of super-slow molecular motions in polymers using a variant of the 2D exchange experiment developed by us. Finally chapter 6 discusses a new experiment, 2D nutation NMR, which makes it possible to study the quadrupole interaction of half-integer spins. 230 refs.; 48 figs.; 8 tabs

Long-time Luminescence Kinetics of Localized excitons and conduction Band Edges Smearing in ZnSe(1-c)Tec Solid Solutions

DEFF Research Database (Denmark)

Klochikhin, O.; Ogloblin, S. G.; Permogorov, S.

2000-01-01

It is shown that the integrated luminescence intensity of localized excitons in solid solutions ZnSe(1 - c)Tec has a component slowly decaying with time. After the excitation above the mobility threshold, the long-time intensity decreases exponentially, with a fractional exponent changing from...

Bedding material affects mechanical thresholds, heat thresholds and texture preference

Science.gov (United States)

Moehring, Francie; O’Hara, Crystal L.; Stucky, Cheryl L.

2015-01-01

It has long been known that the bedding type animals are housed on can affect breeding behavior and cage environment. Yet little is known about its effects on evoked behavior responses or non-reflexive behaviors. C57BL/6 mice were housed for two weeks on one of five bedding types: Aspen Sani Chips® (standard bedding for our institute), ALPHA-Dri®, Cellu-Dri™, Pure-o’Cel™ or TEK-Fresh. Mice housed on Aspen exhibited the lowest (most sensitive) mechanical thresholds while those on TEK-Fresh exhibited 3-fold higher thresholds. While bedding type had no effect on responses to punctate or dynamic light touch stimuli, TEK-Fresh housed animals exhibited greater responsiveness in a noxious needle assay, than those housed on the other bedding types. Heat sensitivity was also affected by bedding as animals housed on Aspen exhibited the shortest (most sensitive) latencies to withdrawal whereas those housed on TEK-Fresh had the longest (least sensitive) latencies to response. Slight differences between bedding types were also seen in a moderate cold temperature preference assay. A modified tactile conditioned place preference chamber assay revealed that animals preferred TEK-Fresh to Aspen bedding. Bedding type had no effect in a non-reflexive wheel running assay. In both acute (two day) and chronic (5 week) inflammation induced by injection of Complete Freund’s Adjuvant in the hindpaw, mechanical thresholds were reduced in all groups regardless of bedding type, but TEK-Fresh and Pure-o’Cel™ groups exhibited a greater dynamic range between controls and inflamed cohorts than Aspen housed mice. PMID:26456764

40 CFR 68.115 - Threshold determination.

Science.gov (United States)

2010-07-01

... (CONTINUED) CHEMICAL ACCIDENT PREVENTION PROVISIONS Regulated Substances for Accidental Release Prevention... process exceeds the threshold. (b) For the purposes of determining whether more than a threshold quantity... portion of the process is less than 10 millimeters of mercury (mm Hg), the amount of the substance in the...

Anaerobic digestion of solid slaughterhouse waste chemically pretreated

Energy Technology Data Exchange (ETDEWEB)

Flores, C.; Montoya, L.; Rodirguez, A.

2009-07-01

One of the mayor problems facing the industrialized world today is to solve environmental contamination and identify efficient treatment to give solution to the current problems like the generation of enormous quantities of liquid and solid wastes. The solid slaughterhouse waste, due to its elevated concentration of biodegradable organics, can be efficiently treated by anaerobic digestion although the high content of lignocellulose materials, makes it a slowly process. (Author)

Anaerobic digestion of solid slaughterhouse waste chemically pretreated

International Nuclear Information System (INIS)

Flores, C.; Montoya, L.; Rodirguez, A.

2009-01-01

One of the mayor problems facing the industrialized world today is to solve environmental contamination and identify efficient treatment to give solution to the current problems like the generation of enormous quantities of liquid and solid wastes. The solid slaughterhouse waste, due to its elevated concentration of biodegradable organics, can be efficiently treated by anaerobic digestion although the high content of lignocellulose materials, makes it a slowly process. (Author)

Towards a unifying basis of auditory thresholds: binaural summation.

Science.gov (United States)

Heil, Peter

2014-04-01

Absolute auditory threshold decreases with increasing sound duration, a phenomenon explainable by the assumptions that the sound evokes neural events whose probabilities of occurrence are proportional to the sound's amplitude raised to an exponent of about 3 and that a constant number of events are required for threshold (Heil and Neubauer, Proc Natl Acad Sci USA 100:6151-6156, 2003). Based on this probabilistic model and on the assumption of perfect binaural summation, an equation is derived here that provides an explicit expression of the binaural threshold as a function of the two monaural thresholds, irrespective of whether they are equal or unequal, and of the exponent in the model. For exponents >0, the predicted binaural advantage is largest when the two monaural thresholds are equal and decreases towards zero as the monaural threshold difference increases. This equation is tested and the exponent derived by comparing binaural thresholds with those predicted on the basis of the two monaural thresholds for different values of the exponent. The thresholds, measured in a large sample of human subjects with equal and unequal monaural thresholds and for stimuli with different temporal envelopes, are compatible only with an exponent close to 3. An exponent of 3 predicts a binaural advantage of 2 dB when the two ears are equally sensitive. Thus, listening with two (equally sensitive) ears rather than one has the same effect on absolute threshold as doubling duration. The data suggest that perfect binaural summation occurs at threshold and that peripheral neural signals are governed by an exponent close to 3. They might also shed new light on mechanisms underlying binaural summation of loudness.

Assessing lead thresholds for phytotoxicity and potential dietary toxicity in selected vegetable crops.

Science.gov (United States)

Hong, C L; Jia, Y B; Yang, X E; He, Z L; Stoffella, P J

2008-04-01

Lead tolerance and accumulation in shoots and edible parts varied with crop species and soil type. The critical Pb concentrations at 10% yield reduction were 24.71, 28.25, and 0.567 mg kg(-1) for pakchoi, celery, and hot pepper, respectively under hydroponic conditions, whereas were 13.1, 3.83, 0.734 mg kg(-1) grown in the Inceptisol and 31.7, 30.0, 0.854 mg kg(-1) in the Alluvial soil, respectively. Based on the threshold of human dietary toxicity for Pb, the critical levels of soil available Pb for pakchoi, celery, and hot pepper were 5.07, 8.06, and 0.48 mg kg(-1) for the Inceptisol, and 1.38, 1.47, and 0.162 mg kg(-1) for the Alluvial soil, respectively. Similarly, the total soil Pb thresholds were different from vegetable species and soil types.

Cluster concentrations in correlated and non-correlated continuum percolation problems

International Nuclear Information System (INIS)

Borstnik, B.; Jesudason, C.G.; Lukman, D.

1996-01-01

The methodologies are developed how to evaluate properties of clusters of correlated and non-correlated particles. As an example of correlated particles, the two dimensional hard core disks with attractive square well potential are taken. Narrow and deep square well potential is used in order to mimic the adhesive potential, suitable for modeling of colloidal systems. Permeable disks in two dimensions are taken as an example of non-correlated systems. In both cases the dependence of cluster concentrations upon the density of particles is studied. Percolation threshold densities and critical exponents which govern the zeroth, first and second moments of cluster distributions are evaluated. It is found that the calculation of density dependence of cluster concentrations gives enough information to evaluate the percolation threshold density, some critical exponents, as well as to reproduce the Rushbrooke scaling law

Spike-threshold adaptation predicted by membrane potential dynamics in vivo.

Directory of Open Access Journals (Sweden)

Bertrand Fontaine

2014-04-01

Full Text Available Neurons encode information in sequences of spikes, which are triggered when their membrane potential crosses a threshold. In vivo, the spiking threshold displays large variability suggesting that threshold dynamics have a profound influence on how the combined input of a neuron is encoded in the spiking. Threshold variability could be explained by adaptation to the membrane potential. However, it could also be the case that most threshold variability reflects noise and processes other than threshold adaptation. Here, we investigated threshold variation in auditory neurons responses recorded in vivo in barn owls. We found that spike threshold is quantitatively predicted by a model in which the threshold adapts, tracking the membrane potential at a short timescale. As a result, in these neurons, slow voltage fluctuations do not contribute to spiking because they are filtered by threshold adaptation. More importantly, these neurons can only respond to input spikes arriving together on a millisecond timescale. These results demonstrate that fast adaptation to the membrane potential captures spike threshold variability in vivo.

Statistical Algorithm for the Adaptation of Detection Thresholds

DEFF Research Database (Denmark)

Stotsky, Alexander A.

2008-01-01

Many event detection mechanisms in spark ignition automotive engines are based on the comparison of the engine signals to the detection threshold values. Different signal qualities for new and aged engines necessitate the development of an adaptation algorithm for the detection thresholds...... remains constant regardless of engine age and changing detection threshold values. This, in turn, guarantees the same event detection performance for new and aged engines/sensors. Adaptation of the engine knock detection threshold is given as an example. Udgivelsesdato: 2008...

Perspective: Uses and misuses of thresholds in diagnostic decision making.

Science.gov (United States)

Warner, Jeremy L; Najarian, Robert M; Tierney, Lawrence M

2010-03-01

The concept of thresholds plays a vital role in decisions involving the initiation, continuation, and completion of diagnostic testing. Much research has focused on the development of explicit thresholds, in the form of practice guidelines and decision analyses. However, these tools are used infrequently; most medical decisions are made at the bedside, using implicit thresholds. Study of these thresholds can lead to a deeper understanding of clinical decision making. The authors examine some factors constituting individual clinicians' implicit thresholds. They propose a model for static thresholds using the concept of situational gravity to explain why some thresholds are high, and some low. Next, they consider the hypothetical effects of incorrect placement of thresholds (miscalibration) and changes to thresholds during diagnosis (manipulation). They demonstrate these concepts using common clinical scenarios. Through analysis of miscalibration of thresholds, the authors demonstrate some common maladaptive clinical behaviors, which are nevertheless internally consistent. They then explain how manipulation of thresholds gives rise to common cognitive heuristics including premature closure and anchoring. They also discuss the case where no threshold has been exceeded despite exhaustive collection of data, which commonly leads to application of the availability or representativeness heuristics. Awareness of implicit thresholds allows for a more effective understanding of the processes of medical decision making and, possibly, to the avoidance of detrimental heuristics and their associated medical errors. Research toward accurately defining these thresholds for individual physicians and toward determining their dynamic properties during the diagnostic process may yield valuable insights.

Is action potential threshold lowest in the axon?

NARCIS (Netherlands)

Kole, Maarten H. P.; Stuart, Greg J.

2008-01-01

Action potential threshold is thought to be lowest in the axon, but when measured using conventional techniques, we found that action potential voltage threshold of rat cortical pyramidal neurons was higher in the axon than at other neuronal locations. In contrast, both current threshold and voltage

Determination of Low Concentrations of Acetochlor in Water by Automated Solid-Phase Extraction and Gas Chromatography with Mass-Selective Detection

Science.gov (United States)

Lindley, C.E.; Stewart, J.T.; Sandstrom, M.W.

1996-01-01

A sensitive and reliable gas chromatographic/mass spectrometric (GC/MS) method for determining acetochlor in environmental water samples was developed. The method involves automated extraction of the herbicide from a filtered 1 L water sample through a C18 solid-phase extraction column, elution from the column with hexane-isopropyl alcohol (3 + 1), and concentration of the extract with nitrogen gas. The herbicide is quantitated by capillary/column GC/MS with selected-ion monitoring of 3 characteristic ions. The single-operator method detection limit for reagent water samples is 0.0015 ??g/L. Mean recoveries ranged from about 92 to 115% for 3 water matrixes fortified at 0.05 and 0.5 ??g/L. Average single-operator precision, over the course of 1 week, was better than 5%.

Supra-threshold epidermis injury from near-infrared laser radiation prior to ablation onset

Science.gov (United States)

DeLisi, Michael P.; Peterson, Amanda M.; Lile, Lily A.; Noojin, Gary D.; Shingledecker, Aurora D.; Stolarski, David J.; Zohner, Justin J.; Kumru, Semih S.; Thomas, Robert J.

2017-02-01

With continued advancement of solid-state laser technology, high-energy lasers operating in the near-infrared (NIR) band are being applied in an increasing number of manufacturing techniques and medical treatments. Safety-related investigations of potentially harmful laser interaction with skin are commonplace, consisting of establishing the maximum permissible exposure (MPE) thresholds under various conditions, often utilizing the minimally-visible lesion (MVL) metric as an indication of damage. Likewise, characterization of ablation onset and velocity is of interest for therapeutic and surgical use, and concerns exceptionally high irradiance levels. However, skin injury response between these two exposure ranges is not well understood. This study utilized a 1070-nm Yb-doped, diode-pumped fiber laser to explore the response of excised porcine skin tissue to high-energy exposures within the supra-threshold injury region without inducing ablation. Concurrent high-speed videography was employed to assess the effect on the epidermis, with a dichotomous response determination given for three progressive damage event categories: observable permanent distortion on the surface, formation of an epidermal bubble due to bounded intra-cutaneous water vaporization, and rupture of said bubble during laser exposure. ED50 values were calculated for these categories under various pulse configurations and beam diameters, and logistic regression models predicted injury events with approximately 90% accuracy. The distinction of skin response into categories of increasing degrees of damage expands the current understanding of high-energy laser safety while also underlining the unique biophysical effects during induced water phase change in tissue. These observations could prove useful in augmenting biothermomechanical models of laser exposure in the supra-threshold region.

Solid-State Threshold Accelerometer Chip.

Science.gov (United States)

1987-03-28

adhered to another gold surface and *welded.’ Literature on surface wear and friction effects with various surface treatments often show that gold-on...LASTING 0.1 SECONDS.i i. -- S *.I CIC ~14. MATERIAL - ALUMINUM CROSSECTION - F/;%f 蕻 n, . t -. to1 77/ - CA6 /je /24 h,6qe 3/,/.o Z#0 1/c 0, &o

Applying Threshold Concepts to Finance Education

Science.gov (United States)

Hoadley, Susan; Wood, Leigh N.; Tickle, Leonie; Kyng, Tim

2016-01-01

Purpose: The purpose of this paper is to investigate and identify threshold concepts that are the essential conceptual content of finance programmes. Design/Methodology/Approach: Conducted in three stages with finance academics and students, the study uses threshold concepts as both a theoretical framework and a research methodology. Findings: The…

Computational algorithm for molybdenite concentrate annealing

International Nuclear Information System (INIS)

Alkatseva, V.M.

1995-01-01

Computational algorithm is presented for annealing of molybdenite concentrate with granulated return dust and that of granulated molybdenite concentrate. The algorithm differs from the known analogies for sulphide raw material annealing by including the calculation of return dust mass in stationary annealing; the latter quantity varies form the return dust mass value obtained in the first iteration step. Masses of solid products are determined by distribution of concentrate annealing products, including return dust and benthonite. The algorithm is applied to computations for annealing of other sulphide materials. 3 refs

Batch tests of a microbial fuel cell for electricity generation from spent organic extracts from hydrogenogenic fermentation of organic solid wastes

International Nuclear Information System (INIS)

Carmona-Martinez, A.; Solorza-Feria, O.; Poggi-Varaldo, H. M.

2009-01-01

Hydrogenogenic fermentative processes of organic solid wastes produce spent solids that contain substantial concentrations of low molecular weight organic acids and solvents. The spent solids can be extracted with wastewater to give a stream containing concentrated, degradable organic compounds. (Author)

Fungal Invertase Expression in Solid-State Fermentation

Directory of Open Access Journals (Sweden)

Cuitlahuac Aranda

2006-01-01

Full Text Available In this study invertase activity expression in Aspergillus niger Aa-20 was evaluated under different concentrations of two substrates using solid-state fermentation (SSF on polyurethane foam. Glucose was used as repressor and sucrose was the inducer. Invertase production increased when glucose was present in the medium (up to 100 g/L; however, higher concentration than this reduced the enzyme production. Induction-repression ratio obtained using any glucose concentration was at least 2.5 times higher than that under basal conditions (without inducer.

Numerical modelling of pyrolysis in normal and reduced oxygen concentration

International Nuclear Information System (INIS)

Kacem, Ahmed

2016-01-01

The predictive capability of computational fluid dynamics (CFD) fire models depends on the accuracy with which the source term due to fuel pyrolysis can be determined. The pyrolysis rate is a key parameter controlling fire behavior, which in turn drives the heat feedback from the flame to the fuel surface. In the present study an in-depth pyrolysis model of a semi-transparent solid fuel (here, clear polymethyl methacrylate or PMMA) with spectrally-resolved radiation and a moving gas/solid interface was coupled with the CFD code ISIS of the IRSN which included turbulence, combustion and radiation for the gas phase. A combined genetic algorithm/pyrolysis model was used with Cone Calorimeter data from a pure pyrolysis experiment to estimate a unique set of kinetic parameters for PMMA pyrolysis. In order to validate the coupled model, ambient air flaming experiments were conducted on square slabs of PMMA with side lengths of 10, 20 and 40 cm. From measurements at the center of the slab, it was found that i) for any sample size, the experimental regression rate becomes almost constant with time, and ii) although the radiative and total heat transfers increase significantly with the sample size, the radiative contribution to the total heat flux remains almost constant (∼80%). Coupled model results show a fairly good agreement with the literature and with current measurements of the heat fluxes, gas temperature and regressing surface rate at the center of the slabs. Discrepancies between predicted and measured total pyrolysis rate are observed, which result from the underestimation of the flame heat flux feedback at the edges of the slab, as confirmed by the comparison between predicted and observed topography of burned samples. Predicted flame heights based on a threshold temperature criterion were found to be close to those deduced from the correlation of Heskestad. Finally, in order to predict the pyrolysis of PMMA under reduced ambient oxygen concentration, a two

Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate

International Nuclear Information System (INIS)

Herrero, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Vinals, J.

2005-01-01

Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs

The asymmetry of U.S. monetary policy: Evidence from a threshold Taylor rule with time-varying threshold values

Science.gov (United States)

Zhu, Yanli; Chen, Haiqiang

2017-05-01

In this paper, we revisit the issue whether U.S. monetary policy is asymmetric by estimating a forward-looking threshold Taylor rule with quarterly data from 1955 to 2015. In order to capture the potential heterogeneity for regime shift mechanism under different economic conditions, we modify the threshold model by assuming the threshold value as a latent variable following an autoregressive (AR) dynamic process. We use the unemployment rate as the threshold variable and separate the sample into two periods: expansion periods and recession periods. Our findings support that the U.S. monetary policy operations are asymmetric in these two regimes. More precisely, the monetary authority tends to implement an active Taylor rule with a weaker response to the inflation gap (the deviation of inflation from its target) and a stronger response to the output gap (the deviation of output from its potential level) in recession periods. The threshold value, interpreted as the targeted unemployment rate of monetary authorities, exhibits significant time-varying properties, confirming the conjecture that policy makers may adjust their reference point for the unemployment rate accordingly to reflect their attitude on the health of general economy.

Can we set a global threshold age to define mature forests?

Directory of Open Access Journals (Sweden)

Philip Martin

2016-02-01

Full Text Available Globally, mature forests appear to be increasing in biomass density (BD. There is disagreement whether these increases are the result of increases in atmospheric CO2 concentrations or a legacy effect of previous land-use. Recently, it was suggested that a threshold of 450 years should be used to define mature forests and that many forests increasing in BD may be younger than this. However, the study making these suggestions failed to account for the interactions between forest age and climate. Here we revisit the issue to identify: (1 how climate and forest age control global forest BD and (2 whether we can set a threshold age for mature forests. Using data from previously published studies we modelled the impacts of forest age and climate on BD using linear mixed effects models. We examined the potential biases in the dataset by comparing how representative it was of global mature forests in terms of its distribution, the climate space it occupied, and the ages of the forests used. BD increased with forest age, mean annual temperature and annual precipitation. Importantly, the effect of forest age increased with increasing temperature, but the effect of precipitation decreased with increasing temperatures. The dataset was biased towards northern hemisphere forests in relatively dry, cold climates. The dataset was also clearly biased towards forests <250 years of age. Our analysis suggests that there is not a single threshold age for forest maturity. Since climate interacts with forest age to determine BD, a threshold age at which they reach equilibrium can only be determined locally. We caution against using BD as the only determinant of forest maturity since this ignores forest biodiversity and tree size structure which may take longer to recover. Future research should address the utility and cost-effectiveness of different methods for determining whether forests should be classified as mature.

Model Threshold untuk Pembelajaran Memproduksi Pantun Kelas XI

Directory of Open Access Journals (Sweden)

Fitri Nura Murti

2017-03-01

Full Text Available Abstract: The learning pantun method in schools provided less opportunity to develop the students’ creativity in producing pantun. This situation was supported by the result of the observation conducted on eleventh graders at SMAN 2 Bondowoso. It showed that the students tend to plagiarize their pantun. The general objective of this research and development is to develop Threshold Pantun model for learning to produce pantun for elevent graders. The product was presented in guidance book for teachers entitled “Pembelajaran Memproduksi Pantun Menggunakan Model Threshold Pantun untuk Kelas XI”. This study adapted design method of Borg-Gall’s R&D procedure. The result of this study showed that Threshold Pantun model was appropriate to be implemented for learning to produce pantun. Key Words: Threshold Pantun model, produce pantun Abstrak: Pembelajaran pantun di sekolah selama ini kurang mengembangkan kreativitas siswa dalam memproduksi pantun. Hal tersebut dikuatkan oleh hasil observasi siswa kelas XI SMAN 2 Bondowoso yang menunjukkan adanya kecenderungan produk siswa bersifat plagiat. Tujuan penelitian dan pengembangan ini secara umum adalah mengembangkan model Threshold Pantun untuk pembelajaran memproduksi pantun kelas XI..Produk disajikan dalam bentuk buku panduan bagi guru dengan judul “Pembelajaran Memproduksi Pantun Menggunakan Model Threshold Pantun untuk Kelas XI”. Penelitian ini menggunakan rancangan penelitian yang diadaptasi dari prosedur penelitian dan pengembangan Borg dan Gall. Berdasarkan hasil validasi model Threshold Pantun untuk pembelajaran memproduksi pantun layak diimplementasikan. Kata kunci: model Threshold Pantun, memproduksi pantun

Modeling Dissolved Solids in the Rincon Valley, New Mexico Using RiverWare

Science.gov (United States)

Abudu, S.; Ahn, S. R.; Sheng, Z.

2017-12-01

Simulating transport and storage of dissolved solids in surface water and underlying alluvial aquifer is essential to evaluate the impacts of surface water operations, groundwater pumping, and climate variability on the spatial and temporal variability of salinity in the Rio Grande Basin. In this study, we developed a monthly RiverWare water quantity and quality model to simulate the both concentration and loads of dissolved solids for the Rincon Valley, New Mexico from Caballo Reservoir to Leasburg Dam segment of the Rio Grande. The measured flows, concentration and loads of dissolved solids in the main stream and drains were used to develop RiveWare model using 1980-1988 data for calibration, and 1989-1995 data for validation. The transport of salt is tracked using discretized salt and post-process approaches. Flow and salt exchange between the surface water and adjacent groundwater objects is computed using "soil moisture salt with supplemental flow" method in the RiverWare. In the groundwater objects, the "layered salt" method is used to simulate concentration of the dissolved solids in the shallow groundwater storage. In addition, the estimated local inflows under different weather conditions by using a calibrated Soil Water Assessment Tool (SWAT) were fed into the RiverWare to refine the simulation of the flow and dissolved solids. The results show the salt concentration and loads increased at Leasburg Dam, which indicates the river collects salts from the agricultural return flow and the underlying aquifer. The RiverWare model with the local inflow fed by SWAT delivered the better quantification of temporal and spatial salt exchange patterns between the river and the underlying aquifer. The results from the proposed modeling approach can be used to refine the current mass-balance budgets for dissolved-solids transport in the Rio Grande, and provide guidelines for planning and decision-making to control salinity in arid river environment.

The H-mode power threshold in JET

Energy Technology Data Exchange (ETDEWEB)

Start, D F.H.; Bhatnagar, V P; Campbell, D J; Cordey, J G; Esch, H P.L. de; Gormezano, C; Hawkes, N; Horton, L; Jones, T T.C.; Lomas, P J; Lowry, C; Righi, E; Rimini, F G; Saibene, G; Sartori, R; Sips, G; Stork, D; Thomas, P; Thomsen, K; Tubbing, B J.D.; Von Hellermann, M; Ward, D J [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

1994-07-01

New H-mode threshold data over a range of toroidal field and density values have been obtained from the present campaign. The scaling with n{sub e} B{sub t} is almost identical with that of the 91/92 period for the same discharge conditions. The scaling with toroidal field alone gives somewhat higher thresholds than the older data. The 1991/2 database shows a scaling of P{sub th} (power threshold) with n{sub e} B{sub t} which is approximately linear and agrees well with that observed on other tokamaks. For NBI and carbon target tiles the threshold power is a factor of two higher with the ion {Nu}B drift away from the target compared with the value found with the drift towards the target. The combination of ICRH and beryllium tiles appears to be beneficial for reducing P{sub th}. The power threshold is largely insensitive to plasma current, X-point height and distance between the last closed flux surface and the limiter, at least for values greater than 2 cm. (authors). 3 refs., 6 figs.

QRS Detection Based on Improved Adaptive Threshold

Directory of Open Access Journals (Sweden)

Xuanyu Lu

2018-01-01

Full Text Available Cardiovascular disease is the first cause of death around the world. In accomplishing quick and accurate diagnosis, automatic electrocardiogram (ECG analysis algorithm plays an important role, whose first step is QRS detection. The threshold algorithm of QRS complex detection is known for its high-speed computation and minimized memory storage. In this mobile era, threshold algorithm can be easily transported into portable, wearable, and wireless ECG systems. However, the detection rate of the threshold algorithm still calls for improvement. An improved adaptive threshold algorithm for QRS detection is reported in this paper. The main steps of this algorithm are preprocessing, peak finding, and adaptive threshold QRS detecting. The detection rate is 99.41%, the sensitivity (Se is 99.72%, and the specificity (Sp is 99.69% on the MIT-BIH Arrhythmia database. A comparison is also made with two other algorithms, to prove our superiority. The suspicious abnormal area is shown at the end of the algorithm and RR-Lorenz plot drawn for doctors and cardiologists to use as aid for diagnosis.

End-Member Formulation of Solid Solutions and Reactive Transport

Energy Technology Data Exchange (ETDEWEB)

Lichtner, Peter C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

A model for incorporating solid solutions into reactive transport equations is presented based on an end-member representation. Reactive transport equations are solved directly for the composition and bulk concentration of the solid solution. Reactions of a solid solution with an aqueous solution are formulated in terms of an overall stoichiometric reaction corresponding to a time-varying composition and exchange reactions, equivalent to reaction end-members. Reaction rates are treated kinetically using a transition state rate law for the overall reaction and a pseudo-kinetic rate law for exchange reactions. The composition of the solid solution at the onset of precipitation is assumed to correspond to the least soluble composition, equivalent to the composition at equilibrium. The stoichiometric saturation determines if the solid solution is super-saturated with respect to the aqueous solution. The method is implemented for a simple prototype batch reactor using Mathematica for a binary solid solution. Finally, the sensitivity of the results on the kinetic rate constant for a binary solid solution is investigated for reaction of an initially stoichiometric solid phase with an undersaturated aqueous solution.

Thresholds in the sliding resistance of simulated basal ice

Directory of Open Access Journals (Sweden)

L. F. Emerson

2007-10-01

Full Text Available We report laboratory determinations of the shear resistance to sliding melting ice with entrained particles over a hard, impermeable surface. With higher particle concentrations and larger particle sizes, Coulomb friction at particle-bed contacts dominates and the shear stress increases linearly with normal load. We term this the sandy regime. When either particle concentration or particle size is reduced below a threshold, the dependence of shear resistance on normal load is no longer statistically significant. We term this regime slippery. We use force and mass balance considerations to examine the flow of melt water beneath the simulated basal ice. At high particle concentrations, the transition from sandy to slippery behavior occurs when the particle size is comparable to the thickness of the melt film that separates the sliding ice from its bed. For larger particle sizes, a transition from sandy to slippery behavior occurs when the particle concentration drops sufficiently that the normal load is no longer transferred completely to the particle-bed contacts. We estimate that the melt films separating the particles from the ice are approximately 0.1 µm thick at this transition. Our laboratory results suggest the potential for abrupt transitions in the shear resistance beneath hard-bedded glaciers with changes in either the thickness of melt layers or the particle loading.

Solid-solid interactions in Co3O4-MoO3/MgO system

International Nuclear Information System (INIS)

Radwan, Nagi R.E.; Ghozza, Ahmed M.; El-Shobaky, Gamil A.

2003-01-01

Cobalt/magnesium mixed oxide solids and cobalt-molybdenum/magnesium mixed oxide solids were prepared by thermal decomposition of basic magnesium carbonate pretreated with different proportions of cobalt nitrate and then with calculated amounts of ammonium molybdate. The proportions of cobalt expressed as Co 3 O 4 were 0.1, 0.2 and 0.3 mol while the concentrations of molybdenum expressed as mol% MoO 3 were 2.5 and 5.0. The prepared mixed solid specimens were calcined in air at 400-1000 deg. C. The solid-solid interactions in Co 3 O 4 -MoO 3 were investigated using DTA, TG and X-ray powder diffraction (XRD) techniques. The results obtained revealed that MgO dissolved cobalt oxide in its lattice forming CoO-MgO solid solution. The amount of cobalt dissolved increases by increasing the temperature in the range 800-1000 deg. C. This finding was confirmed by X-ray diffractograms in which all the diffraction lines of cobalt oxide disappeared at 1000 deg. C. MoO 3 present interacted readily with MgO and cobalt oxide by heat treatment at temperature starting from 400 deg. C producing MgMoO 4 and CoMoO 4 which remained stable by heating at 1000 deg. C. The impregnation of basic magnesium carbonate with cobalt nitrate much enhanced its thermal decomposition yielding MgO, which decomposed completely at 395.5 deg. C instead of 525 deg. C. The formation of magnesium cobaltite (MgCo 2 O 4 ) has been ruled out via XRD investigation at relatively high diffraction angles

Assessing the Variability of Heavy Metal Concentrations in Liquid-Solid Two-Phase and Related Environmental Risks in the Weihe River of Shaanxi Province, China

Science.gov (United States)

Song, Jinxi; Yang, Xiaogang; Zhang, Junlong; Long, Yongqing; Zhang, Yan; Zhang, Taifan

2015-01-01

Accurate estimation of the variability of heavy metals in river water and the hyporheic zone is crucial for pollution control and environmental management. The biotoxicities and potential ecological risks of heavy metals (Cu, Zn, Pb, Cd) in a solid-liquid two-phase system were estimated using the Geo-accumulation Index, Potential Ecological Risk Assessment and Quality Standard Index methods in the Weihe River of Shaanxi Province, China. Water and sediment samples were collected from five study sites during spring, summer and winter, 2013. The dominant species in the streambed sediments were chironomids and flutter earthworm, whose bioturbation mainly ranged from 0 to 20 cm. The concentrations of heavy metals in surface water and pore water varied obviously in spring and summer. The degrees of concentration of Cu and Cd in spring and summer were higher than the U.S. water quality Criteria Maximum Concentrations. Furthermore, the biotoxicities of Pb and Zn demonstrated season-spatial variations. The concentrations of Cu, Zn, Pb and Cd in spring and winter were significantly higher than those in summer, and the pollution levels also varied obviously in different layers of the sediments. Moreover, the pollution level of Cd was the most serious, as estimated by all three assessment methods. PMID:26193293

Theoretical studies on core-level spectra of solids

International Nuclear Information System (INIS)

Kotani, Akio

1995-01-01

I present a review on theoretical studies of core-level spectra (CLS) in solids. In CLS, the dynamical response of outer electrons to a core hole is reflected through the screening of core hole potential. Impurity Anderson model (IAM) or cluster model is successfully applied to the analysis of X-ray photoemission spectra (XPS) and X-ray absorption spectra (XAS) in f and d electron systems, where the f and d electron states are hybridized with the other valence or conduction electron states. The effect of the core-hole potential in the final state of XPS and XAS plays an important role, as well as the solid state hybridization and intra-atomic multiplet coupling effects. As typical examples, the calculated results for XPS of rare-earth compounds and transition metal compounds are shown, and some discussions are given. As a subject of remarkable progress with high brightness synchrotron radiation sources, I discuss some theoretical aspects of X-ray emission spectra (XES) and their resonant enhancement at the X-ray absorption threshold. Some experimental data and their theoretical analysis are also given. (author)

The threshold for diagnosing impaired fasting glucose : a position statement by the European Diabetes Epidemiology Group

NARCIS (Netherlands)

Forouhi, NG; Balkau, B; Borch-Johnsen, K; Dekker, J; Glumer, C; Qiao, Q; Spijkerman, A; Stolk, R; Tabac, A; Wareham, NJ

The category of IFG was introduced in the late 1990s to denote a state of non-diabetic hyperglycaemia defined by a fasting plasma glucose (FPG) concentration between 6.1 and 6.9 mmol/l. In 2003 the American Diabetes Association recommended that this diagnostic threshold be lowered to 5.6 mmol/l. The

Threshold enhancement of diphoton resonances

Directory of Open Access Journals (Sweden)

Aoife Bharucha

2016-10-01

Full Text Available We revisit a mechanism to enhance the decay width of (pseudo-scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. Motivated by the recent LHC data, indicating the presence of an excess in the diphoton spectrum at approximately 750 GeV, we illustrate this threshold enhancement mechanism in the case of a 750 GeV pseudoscalar boson A with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 12MA threshold and a small decay width, <1 MeV. The implications of such a threshold enhancement are discussed in two explicit scenarios: i the Minimal Supersymmetric Standard Model in which the A state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through loops of charginos with masses close to 12MA and ii a two Higgs doublet model in which A is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. In both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the A resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

Cross-Linked Solid Polymer Electrolyte for All-Solid-State Rechargeable Lithium Batteries

International Nuclear Information System (INIS)

Ben youcef, Hicham; Garcia-Calvo, Oihane; Lago, Nerea; Devaraj, Shanmukaraj; Armand, Michel

2016-01-01

Semi-interpenetrated network Solid Polymer Electrolytes (SPEs) were fabricated by UV-induced cross-linking of poly(ethyleneglycol) diacrylate (PEGDA) and divinylbenzene (DVB) within a poly(ethyleneoxide) (PEO) matrix (M v = 5 × 10 6 g mol −1 ), comprising lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI), at a molar ratio of EO:Li ∼ 30:1. The influence of the DVB content on the final SPE properties was investigated in detail. An increase of DVB concentration resulted in self-standing polymer electrolytes. The DVB cross-linker incorporation was found to decrease the crystallinity of the PEO matrix from 34% to 23%, with a decrease in the melting temperature (T m ) of the membrane from 50 °C to 34 °C. Moreover, the influence of the DVB concentration on the ionic conductivity was determined for polymer electrolytes with 0, 10, 20 and 45% DVB from room temperature (RT) to 80 °C. The resulting SPEs showed a high electrochemical stability of 4.3 V as well as practical conductivity values exceeding 10 −4 S cm −1 at 70 °C. Cycling performance of these semi-interpenetrated SPE’s have been shown with a Li metal polymer battery and all solid -state Li sulphur battery.

ZnO-PVA nanocomposite films for low threshold optical limiting applications

International Nuclear Information System (INIS)

Viswanath, Varsha; Beenakumari, C.; Muneera, C. I.

2014-01-01

Zinc oxide-PVA nanocomposite films were fabricated adopting a simple method based on solution-casting, incorporating small weight percentages ( −3 M to 7×10 −3 M), and their structure, morphology, linear and low threshold nonlinear optical properties were investigated. The films were characterized as nanostructured ZnO encapsulated between the molecules/chains of the semicrystalline host polymer PVA. The samples exhibited low threshold nonlinear absorption and negative nonlinear refraction, as studied using the Z-scan technique. A switchover from SA to RSA was observed as the concentration of ZnO was increased. The optical limiting of 632.8 nm CW laser light displayed by these nanocomposite films is also demonstrated. The estimated values of the effective coefficients of nonlinear absorption, nonlinear refraction and third-order nonlinear susceptibility, |χ (3) |, compared to those reported for continuous wave laser light excitation, measure up to the highest among them. The results show that the ZnO-PVA nanocomposite films have great potential applications in future optical and photonic devices

ENTRIA workshop. Determine threshold values in radiation protection

International Nuclear Information System (INIS)

Diener, Lisa

2015-01-01

Threshold values affect our daily lives. Whether it concerns traffic or noise regulations, we all experience thresholds on a regular basis. But how are such values generated? The conference ''Determine Thres-hold Values in Radiation Protection'', taking place on January 27th 2015 in Braunschweig, focused on this question. The conference was undertaken in the context of the BMBF-funded interdisciplinary research project ''ENTRIA - Disposal Options for Radioactive Residues''. It aimed to stimulate a cross-disciplinary discussion. Spea-kers from different disciplinary backgrounds talked about topics like procedures of setting threshold values, standards for evaluating dosages, and public participation in the standardization of threshold values. Two major theses emerged: First, setting threshold values always requires considering contexts and protection targets. Second, existing uncertainties must be communicated in and with the public. Altogether, the conference offered lots of input and issues for discussion. In addition, it raised interesting and important questions for further and ongoing work in the research project ENTRIA.

Thresholds of ion turbulence in tokamaks

International Nuclear Information System (INIS)

Garbet, X.; Laurent, L.; Mourgues, F.; Roubin, J.P.; Samain, A.; Zou, X.L.

1991-01-01

The linear thresholds of ionic turbulence are numerically calculated for the Tokamaks JET and TORE SUPRA. It is proved that the stability domain at η i >0 is determined by trapped ion modes and is characterized by η i ≥1 and a threshold L Ti /R of order (0.2/0.3)/(1+T i /T e ). The latter value is significantly smaller than what has been previously predicted. Experimental temperature profiles in heated discharges are usually marginal with respect to this criterium. It is also shown that the eigenmodes are low frequency, low wavenumber ballooned modes, which may produce a very large transport once the threshold ion temperature gradient is reached

Effect of dissipation on dynamical fusion thresholds

International Nuclear Information System (INIS)

Sierk, A.J.

1986-01-01

The existence of dynamical thresholds to fusion in heavy nuclei (A greater than or equal to 200) due to the nature of the potential-energy surface is shown. These thresholds exist even in the absence of dissipative forces, due to the coupling between the various collective deformation degrees of freedom. Using a macroscopic model of nuclear shape dynamics, It is shown how three different suggested dissipation mechanisms increase by varying amounts the excitation energy over the one-dimensional barrier required to cause compound-nucleus formation. The recently introduced surface-plus-window dissipation may give a reasonable representation of experimental data on fusion thresholds, in addition to properly describing fission-fragment kinetic energies and isoscalar giant multipole widths. Scaling of threshold results to asymmetric systems is discussed. 48 refs., 10 figs

SOLISOL-handling of solid solutions. Version 1.1

International Nuclear Information System (INIS)

Boerjesson, S.; Emren, A.

1992-09-01

SOLISOL is a C computer program designed to model geochemical reactions involving solid solutions. The program searches equilibrium concentrations of the components in the aqueous phase and the solid solution given by limited quantities of the solid solution components. The equilibrium code PHREEQE is used as a subprogram in SOLISOL. Subprograms external to PHREEQE extract information from PHREEQE results, take care of conserved properties, calculate solubilities and produce inputdata for PHREEQE. The essential idea in this process is to calculate solubilities for the components in terms of saturation indices, and give directions to PHREEQE on how to search for the equilibrium under those constraints. (au)

The influence of roadside solid and vegetation barriers on near-road air quality

Science.gov (United States)

Ghasemian, Masoud; Amini, Seyedmorteza; Princevac, Marko

2017-12-01

The current study evaluates the influence of roadside solid and vegetation barriers on the near-road air quality. Reynolds Averaged Navier-Stokes (RANS) technique coupled with the k - ε realizable turbulence model is utilized to investigate the flow pattern and pollutant concentration. A scalar transport equation is solved for a tracer gas to represent the roadway pollutant emissions. In addition, a broad range of turbulent Schmidt numbers are tested to calibrate the scalar transport equation. Three main scenarios including flat terrain, solid barrier, and vegetative barrier are studied. To validate numerical methodology, predicted pollutant concentration is compared with published wind tunnel data. Results show that the solid barrier induces an updraft motion and lofts the vehicle emission plume. Therefore, the ground-level pollutant concentration decreases compared to the flat terrain. For the vegetation barrier, different sub-scenarios with different vegetation densities ranging from approximately flat terrain to nearly solid barrier are examined. Dense canopies act in a similar manner as a solid barrier and mitigate the pollutant concentration through vertical mixing. On the other hand, the high porosity vegetation barriers reduce the wind speed and lead to a higher pollutant concentration. As the vegetation density increases, i.e. the barrier porosity decreases, the recirculation zone behind the canopy becomes larger and moves toward the canopy. The dense plant canopy with LAD = 3.33m-2m3 can improve the near-road air quality by 10% and high porosity canopy with LAD = 1m-2m3 deteriorates near-road air quality by 15%. The results of this study can be implemented as green infrastructure design strategies by urban planners and forestry organizations.

Why solid-state fermentation is more advantageous over submerged fermentation for converting high concentration of glycerol into Monacolin K by Monascus purpureus 9901: A mechanistic study.

Science.gov (United States)

Zhang, Bo-Bo; Lu, Li-Ping; Xu, Gan-Rong

2015-07-20

The underlying mechanisms by which solid-state fermentation (SSF) was more advantageous over submerged fermentation (SmF) for converting high concentration of glycerol into Monacolin K by Monascus purpureus were investigated innovatively. First, the established kinetic models and kinetic parameters showed that the cell growth, Monacolin K formation and glycerol consumption in SSF were more rapid than those in SmF. Secondly, the comparison of fatty acid composition of mycelial cells indicated a better fluidity and permeability of the cell membrane in SSF than that of SmF, which was also consistent with the difference in the ratio of extracellular/intracellular Monacolin K between the two systems. Thirdly, the phenomenon of glycerol concentration gradient was verified in SSF, which could well explain the resistance effect to high concentration of glycerol in SSF. These new findings provide some important insights to the elucidation of the advantages of SSF for the synthesis of fungal secondary metabolites. Copyright © 2015 Elsevier B.V. All rights reserved.

Smartphone threshold audiometry in underserved primary health-care contexts.

Science.gov (United States)

Sandström, Josefin; Swanepoel, De Wet; Carel Myburgh, Hermanus; Laurent, Claude

2016-01-01

To validate a calibrated smartphone-based hearing test in a sound booth environment and in primary health-care clinics. A repeated-measure within-subject study design was employed whereby air-conduction hearing thresholds determined by smartphone-based audiometry was compared to conventional audiometry in a sound booth and a primary health-care clinic environment. A total of 94 subjects (mean age 41 years ± 17.6 SD and range 18-88; 64% female) were assessed of whom 64 were tested in the sound booth and 30 within primary health-care clinics without a booth. In the sound booth 63.4% of conventional and smartphone thresholds indicated normal hearing (≤15 dBHL). Conventional thresholds exceeding 15 dB HL corresponded to smartphone thresholds within ≤10 dB in 80.6% of cases with an average threshold difference of -1.6 dB ± 9.9 SD. In primary health-care clinics 13.7% of conventional and smartphone thresholds indicated normal hearing (≤15 dBHL). Conventional thresholds exceeding 15 dBHL corresponded to smartphone thresholds within ≤10 dB in 92.9% of cases with an average threshold difference of -1.0 dB ± 7.1 SD. Accurate air-conduction audiometry can be conducted in a sound booth and without a sound booth in an underserved community health-care clinic using a smartphone.