Method for fractional solid-waste sampling and chemical analysis
DEFF Research Database (Denmark)
Riber, Christian; Rodushkin, I.; Spliid, Henrik;
2007-01-01
Chemical characterization of solid waste is a demanding task due to the heterogeneity of the waste. This article describes how 45 material fractions hand-sorted from Danish household waste were subsampled and prepared for chemical analysis of 61 substances. All material fractions were subject to...... repeated particle-size reduction, mixing, and mass reduction until a sufficiently small but representative sample was obtained for digestion prior to chemical analysis. The waste-fraction samples were digested according to their properties for maximum recognition of all the studied substances. By combining...... four subsampling methods and five digestion methods, paying attention to the heterogeneity and the material characteristics of the waste fractions, it was possible to determine 61 substances with low detection limits, reasonable variance, and high accuracy. For most of the substances of environmental...
Fermentation, fractionation and purification of streptokinase by chemical reduction method
Directory of Open Access Journals (Sweden)
M Niakan
2011-05-01
Full Text Available Background and Objectives: Streptokinase is used clinically as an intravenous thrombolytic agent for the treatment of acute myocardial infarction and is commonly prepared from cultures of Streptococcus equisimilis strain H46A. The objective of the present study was the production of streptokinase from strain H46A and purification by chemical reduction method."nMaterials and Methods: The rate of streptokinase production evaluated under the effect of changes on some fermentation factors. Moreover, due to the specific structure of streptokinase, a chemical reduction method employed for the purification of streptokinase from the fermentation broth. The H46A strain of group C streptococcus, was grown in a fermentor. The proper pH adjusted with NaOH under glucose feeding in an optimum temperature. The supernatant of the fermentation product was sterilized by filtration and concentrated by ultrafiltration. The pH of the concentrate was adjusted, cooled, and precipitated by methanol. Protein solution was reduced with dithiothreitol (DTT. Impurities settled down by aldrithiol-2 and the biological activity of supernatant containing streptokinase was determined."nResults: In the fed -batch culture, the rate of streptokinase production increased over two times as compared with the batch culture and the impurities were effectively separated from streptokinase by reduction method."nConclusion: Improvements in SK production are due to a decrease in lag phase period and increase in the growth rate of logarithmic phase. The methods of purification often result in unacceptable losses of streptokinase, but the chemical reduction method give high yield of streptokinase and is easy to perform it.
Asphalt chemical fractionation
International Nuclear Information System (INIS)
Asphalt fractionation were carried out in the Esmeraldas Oil Refinery using n-pentane, SiO2 and different mixture of benzene- methane. The fractions obtained were analyzed by Fourier's Transformed Infrared Spectrophotometry (FTIR)
Chemical extraction methods for assessment of phytoavailable fractions of elements in soils
International Nuclear Information System (INIS)
This study develops extraction methods of phytoavailable fractions of elements in soil for precise estimation of soil-to-plant transfer of radionuclides released from nuclear facilities, such as a reprocessing plant in Rokkasho. The soil-to-plant transfer factor based on the total concentration in soil generally scattered in a few orders of magnitude. This large variance is most likely attributable to ignorance of phytoavailability of radionuclides in soil. The transfer factor based on phytoavailable fractions of the radionuclides extracted from soil is expected to allow more precise estimation of their soil-to-plant transfer. Komatsuna (Brassica rapa L. var. perviridis) cultivated in experimental pots and actual fields was used for investigation. Soil samples collected from 19 agricultural fields in Aomori Prefecture were adapted for the pot experiment. We extracted 40 elements from the soil samples with pure water, 0.01 M HNO3, 1 M NH4OAc or 1 M NH4NO3, and analyzed their concentrations in the extracts. Their contents in komatsuna were determined, and their relationships with the concentrations in the extracts were investigated. Although the correlations between the concentrations in the plants and total concentration in the soils were not significant for most elements measured, zinc and lanthanide elements concentrations in the 0.01 M HNO3, 1 M NH4OAc and 1 M NH4NO3 extracts had significant positive correlations with those in the plants. These extraction methods were suitable for the estimation of phytoavailable fractions for those elements. Concentrations of Sr in the any extracted fractions did not correlate to those in the plants. However, Sr/Ca ratios in the NH4OAc extracted fraction showed significant correlation with the plant Sr concentrations. Although the Sr transfer factor was predicted by the NH4OAc-extractable Ca in soil, introducing the Mg concentration in that fraction and the total carbon concentration in soil as additional parameters could
Chemical extraction methods for assessment of phytoavailable fractions of elements in soils
International Nuclear Information System (INIS)
This study develops extraction methods of phytoavailable fractions of elements in soil for precise estimation of soil-to-plant transfer of radionuclides released from nuclear facilities, such as a reprocessing plant in Rokkasho. The soil-to-plant transfer factor based on the total concentration in soil is generally scattered over a few orders of magnitude. This large variance is likely attributable to ignorance of phytoavailability of radionuclides in soil. The transfer factor based on phytoavailable fractions of the radionuclides extracted from soil is expected to allow more precise estimation of their soil-to-plant transfer. Plant samples cultivated in experimental pots and actual fields were used for investigation. Soil samples collected from 19 agricultural fields in Aomori Prefecture were adapted for the pot experiment. We extracted 40 elements from the soil samples using pure water, 0.01 M HNO3, 1 M NH4OAc or 1 M NH4NO3, and analyzed their concentrations in the extracts. Their contents in the plant samples were determined, and their relations with the concentrations in the extracts were investigated. We had previously studied the relations using Komatsuna (Brassica rapa L. va. perviridis) in fiscal 2004, and reported the following results. The concentrations of Zn and lanthanide elements in the 0.01 M HNO3, 1 M CH3COONH4 and 1 M NH4NO3 extracts had significant positive correlations with those in the plants. Therefore, these extraction methods were suitable for estimation of phytoavailable fractions for the elements. Ratios of Sr/Ca in the NH4OAc extracted fraction also showed a significant correlation with the plant Sr concentrations. The transfer factors based on the ratios were confirmed to explain the Sr concentration in the Komatsuna samples collected from the actual fields, and they showed good agreement. We carried out the same experiment using orchardgrass (Dactylis glomerata), red clover (Trifolium pratense L.) and radish (Raphanus sativus L.) in
International Nuclear Information System (INIS)
During study of technogenic radionuclide interaction with particles of bottom land soils compounds of several types was separated by the method of chemical fractionation: a) 60Co radiocolloids and Eu isotopes with elements being contained in composition of polymeric films as sesquioxides and hydroxides (Fe, Al); b) organometallic complexes of 60Co, 137Cs and Eu isotopes with humus substances of soil as ligands. Substitution H2O2 oxidizer for chromic mixture in used fractionation scheme permits to increase radionuclide separation out of soil into solution by several fold: from 6.5 up to 46% for 60Co, from 1.4 up to 36% for 137Cs and from 5.2-8.5 up to 23-32% for Eu isotopes
Energy Technology Data Exchange (ETDEWEB)
Pettersson, Anita; Claesson, Frida
2009-07-01
Striving to improve the waste handling in an energy and environmental manner has led to an increased flow of waste fractions interesting for energy recovery by combustion, both for heat and power production. The increased flow of various waste fractions with varying chemical compositions results in new demands on the combustion plants. This because operational problems, such as bed sintering, corrosion and deposit formation resulting in expensive shut downs can be caused by relatively small changes in the fuel stream. It is primarily alkali metals in combination with chlorine that cause problems like fouling and corrosion. To avoid these problems, tools for characterization of these fuels to predict combustion processes are needed. Two such tools are the Aabo- and the CEN/TS 15105 methods which both are chemical characterization methods based on leaching. The Aabo-method is a more advanced method and also more time consuming compared to the CEN/TS 15105-method. These methods aim to dissolve and identify the compounds that are reactive during combustion and therefore able to cause combustion problems. Both these methods are developed for the characterization of biofuels but only the Aabo-method has been evaluated for waste fuels. The aim of this study was to evaluate the two methods by characterization of six waste fuels with different composition. In addition also four more homogeneous fuels: coal, straw, wood pellets and municipal sewage sludge. The analyses showed that the Aabo-method gave a more clear picture of the reactive elements in the waste fuel in comparison to the CEN/TS 15105-method. An advantage with the Aabo-method is also that the solid rest obtained after the leaching is analysed giving an element balance of the sample without having to make assumptions. The comparison of the methods showed that the CEN/TS 15105-method does not dissolve large parts of the available calcium in the waste fuel resulting in a large underestimation of the reactive
McKay, David S.; Cooper, Bonnie L.
2010-01-01
This slide presentation describes new fractionation methods that are used to create dust that is respirable for testing the effects of inhalation of lunar dust in preparation for future manned lunar exploration. Because lunar dust is a very limited commodity, a method that does not result in loss of the material had to be developed. The dust separation system that is described incorporates some traditional methods, while preventing the dust from being contaminated or changed in reactivity properties while also limiting losses.
Li, Qian; Wang, Xieyi; Chen, Jun; Liu, Chengmei; Li, Ti; McClements, David Julian; Dai, Taotao; Liu, Jiyan
2016-10-01
An extract isolated from Choerospondias axillaris peels was separated into five fractions using size-exclusion chromatography. The structural composition and mean degree of polymerization (mDP) of these fractions were then characterized by acid-catalysis followed by HPLC analysis. The antioxidant activity of each fraction was determined using a combination of chemical-based methods (DPPH, ABTS(+) radical scavenging activity, ferric-reducing antioxidant power, and phosphomolybdate assay) and a cellular-based assay. All fractions tested were found to have high total phenolics contents and were rich in proanthocyanidins. The mDP of fractions (F1-F5) ranged from 1.92 to 9.25. When tested by the chemical-based assays, the antioxidant activity of the fractions did not depend on molecular weight of the phenolics. Conversely, when tested by the cellular-based assay the antioxidant activity actually decreased with increasing molecular weight of the proanthocyanidins. These experiments highlight the limitations of using chemical-based assays to establish the antioxidant activity of proanthocyanidins within biological systems. PMID:27132855
The purpose of this one-day short course is to train students on methods used to measure in vitro metabolism in fish and extrapolate this information to the intact animal. This talk is one of four presentations given by course instructors. The first part of this talk provides a...
Chemical composition of material fractions in Danish household waste
DEFF Research Database (Denmark)
Riber, Christian; Petersen, Claus; Christensen, Thomas Højlund
2009-01-01
The chemical composition of Danish household waste was determined by two approaches: a direct method where the chemical composition (61 substances) of 48 material fractions was determined after hand sorting of about 20 tonnes of waste collected from 2200 households; and an indirect method where...... batches of 80-1200 tonnes of unsorted household waste was incinerated and the content of the waste determined from the content of the outputs from the incinerator. The indirect method is believed to better represent the small but highly contaminated material fractions (e,g., batteries) than the direct...... method, because of the larger quantities included and the more homogenous material to sample from. Differences between the direct and the direct methods led to corrections in the of heavy metal concentration of a few fractions. The majority of the energy content of the waste originates from organic waste...
Does density fractionation of SOC represent chemically different carbon pools?
Mulvaney, Michael J.; Graham, M.; Xia, K.; Barrera, Victor H.; Botello, Rubén; Saavedra, Ana Karina; Mamani, P.
2012-01-01
Organic matter stabilization is thought to be a process of physical protection and chemical recalcitrance. The determination of recalcitrant soil organic carbon (SOC) often relies on operational definitions provided by various fractionation techniques, usually particle size or density fractionation. However, it is unknown if these operational definitions represent true chemical recalcitrance.
Fractionation method with quench liquid recycle
Energy Technology Data Exchange (ETDEWEB)
Skraba, F.W.
1988-10-11
This patent describes a method of fractionating a hot vapor containing feed, the steps comprising: (a) introducing a hot vapor containing feed into a fractionation zone at a vapor containing feed location near one end of the fractionation zone; (b) removing liquid from a liquid collection zone below the one end of the fractionation zone; (c) passing the thus removed liquid through a heat extraction zone to extract heat from the liquid to produce cooled liquid; (d) returning a first portion of the thus cooled liquid to the fractionation zone as a first reflux liquid at a location intermediate the vapor containing feed location and the other end of the fractionation zone; and (e) returning a second portion of the thus cooled liquid to the fractionation zone as a quench liquid at a location intermediate the vapor containing feed location and the surface of thee liquid in the liquid collection zone wherein the quench liquid is sprayed onto an inclined surface over which condensed liquid from the hot vapor containing feed passes from the fractionation zone and the vapor containing feed location to the surface of the liquid in the liquid collection zone to directly cool the condensed liquid.
Chemical composition of volatile fraction of pakistani peanut and its
International Nuclear Information System (INIS)
Arachis hypogaea Linn (peanut or groundnut) is an economically important crop. Thousands of peanut cultivars are grown in the world and studies have been carried out on these but, to the best of our knowledge, no salient work has been done on Pakistani cultivar so far. Here, we report the chemical composition of volatile fraction of Pakistani cultivar of peanut and its anti radical activities using 1,I-Diphenyl-2-picrylhydrazyl radical (DPPH) scavenging and phospho molybdenum complex (PC) method. This study revealed that Pakistani cultivar exhibited an almost equal antioxidant potential to that of standard, butylated hydroxytoluene (BHT), which was obvious from their IC/sub 50/ values. The IC/sub 50/ value of peanut extract was found to be 13.42 +- 26 macro L/mL, relative to butylated hydroxytoluene, having 12.1 +- 0.92 macro/mL. (author)
Katarzyna Sułkowska-Ziaja; Bożena Muszyńska; Halina Ekiert
2013-01-01
The aim of the study was chemical analysis of polysaccharide fractions from sporocarps of Sarcodon imbricatus collected in natural sites and from the mycelium of in vitro cultures. Three polysaccharide fractions (FOI, FOII, FOIII) were isolated from sporocarps and two (FKI, FKII) from in vitro cultures. Qualitative analysis by HPLC method showed that they are composed of galactose and fucose (FOI, FKI) or glucose and fucose (FOII, FKII). FOIII fraction of the sporocarps consisted of glucose o...
Intelligent numerical methods applications to fractional calculus
Anastassiou, George A
2016-01-01
In this monograph the authors present Newton-type, Newton-like and other numerical methods, which involve fractional derivatives and fractional integral operators, for the first time studied in the literature. All for the purpose to solve numerically equations whose associated functions can be also non-differentiable in the ordinary sense. That is among others extending the classical Newton method theory which requires usual differentiability of function. Chapters are self-contained and can be read independently and several advanced courses can be taught out of this book. An extensive list of references is given per chapter. The book’s results are expected to find applications in many areas of applied mathematics, stochastics, computer science and engineering. As such this monograph is suitable for researchers, graduate students, and seminars of the above subjects, also to be in all science and engineering libraries.
Physico-chemical characterisation of material fractions in household waste
DEFF Research Database (Denmark)
Götze, Ramona; Boldrin, Alessio; Scheutz, Charlotte;
2016-01-01
to the data selection from literature. Overall, 97 publications were reviewed with respect to employed characterisation method, regional origin of the waste, number of investigated parameters and material fractions and other qualitative aspects. Descriptive statistical analysis of the reported physico...
Wölz, Jan
2009-01-01
Scope of the present study is the development and application of aquatic in vitro bioassays and methods of effect-directed analysis (EDA). It aims at investigating contamination of suspended particulate matter (SPM) and pollution of inundated sites and riparian aquifer, respectively. In the first part of this study, SPM was sampled during flood events and toxicological activities were determined. The second part of the study dealt with possible conflict of interests between flood management (...
A short remark on fractional variational iteration method
Energy Technology Data Exchange (ETDEWEB)
He, Ji-Huan, E-mail: hejihuan@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China)
2011-09-05
This Letter compares the classical variational iteration method with the fractional variational iteration method. The fractional complex transform is introduced to convert a fractional differential equation to its differential partner, so that its variational iteration algorithm can be simply constructed. -- Highlights: → The variational iteration method and its fractional modification are compared. → The demerits arising are overcome by the fractional complex transform. → The Letter provides a powerful tool to solving fractional differential equations.
A short remark on fractional variational iteration method
International Nuclear Information System (INIS)
This Letter compares the classical variational iteration method with the fractional variational iteration method. The fractional complex transform is introduced to convert a fractional differential equation to its differential partner, so that its variational iteration algorithm can be simply constructed. -- Highlights: → The variational iteration method and its fractional modification are compared. → The demerits arising are overcome by the fractional complex transform. → The Letter provides a powerful tool to solving fractional differential equations.
Investigation of the chemical composition of mineral fractions of the Tsarev chondrite
Energy Technology Data Exchange (ETDEWEB)
Semenova, L.F.; Fisenko, A.V.; Kashkarova, V.G.; Melnikova, L.N.; Bezrogova, E.V.; Pomytkina, V.A.; Lavrukhina, A.K.
1984-01-01
A selective-dissolution method was used to study the chemical composition of mineral fractions of the Tsarev chondrite. Redistributions of Na, K, and P were found in mineral fractions of L-chondrites which have experienced different degrees of impact metamorphism. It is shown that the normative composition of inclusions in olivine in the Tsarev chondrite is characterized by a high content of diopside and anorthite components. 24 references.
Abdel-Salam, Emad A-B; Hassan, Gmal F
2015-01-01
In this paper, the fractional projective Riccati expansion method is proposed to solve fractional differential equations. To illustrate the effectiveness of the method, we discuss the space-time fractional Burgers equation, the space-time fractional mKdV equation and time fractional biological population model. The solutions are expressed in terms of fractional hyperbolic functions. These solutions are useful to understand the mechanisms of the complicated nonlinear physical phenomena and fractional differential equations. Among these solutions, some are found for the first time. The fractal index for the obtained results is equal to one. Counter examples to compute the fractal index are introduced in appendix.
Directory of Open Access Journals (Sweden)
Katarzyna Sułkowska-Ziaja
2013-12-01
Full Text Available The aim of the study was chemical analysis of polysaccharide fractions from sporocarps of Sarcodon imbricatus collected in natural sites and from the mycelium of in vitro cultures. Three polysaccharide fractions (FOI, FOII, FOIII were isolated from sporocarps and two (FKI, FKII from in vitro cultures. Qualitative analysis by HPLC method showed that they are composed of galactose and fucose (FOI, FKI or glucose and fucose (FOII, FKII. FOIII fraction of the sporocarps consisted of glucose only. Molecular weights of isolated fractions ranged from 3.8 to 16.3 kDa for fractions from the sporocarps and from 5.8 to 14.7 kDa for that ones isolated from in vitro culture. The total percentage of sugar content for all fractions ranged from 97.8% to 99.1%. The percentage of uronic acids contents in acidic fractions was 2.6% and 2.7% for the FOI and FKI respectively. The work included also an assessment of cytotoxic activity of polysaccharide fractions in relation to tumor cell lines of human breast cancer MCV-7. FOI polysaccharide fraction of the sporocarps inhibited the growth of cancer cells in 50% compared to the control at a concentration of 0.0125%, while the polysaccharide fraction FKI from in vitro cultures inhibited cell growth in a concentration of 0.016%.
Biological, chemical, electrochemical, and photochemical fractionation of Fe isotopes
John, S.; King, A.; Hutchins, D.; Adkins, J. F.; Fu, F.; Wasson, A.; Hodierne, C.
2012-12-01
Iron is an important nutrient for life in the ocean, where low Fe concentrations often limit the growth of marine phytoplankton. Fe stable isotope ratios (δ56Fe) are a potentially valuable new tool for studying the marine biological cycling of Fe. In order to effectively use Fe isotopes as a biological tracer, however, it is important to parameterize the isotope effect for biological uptake. We have therefore measured the biological fractionation of Fe isotopes by the marine diatoms Thalassiosira pseudonana, T. oceanica, and Phaeodactylum tricornutum in culture. During biological Fe acquisition, Fe(III) is often first reduced from Fe(III) to Fe(II), either in seawater or at the cell surface. Therefore, we have also measured the isotope effect for Fe(III) reduction by chemical, electrochemical, and photochemical processes. Diatoms were cultured in EDTA or NTA buffered media under varying Fe concentrations from Fe-sufficiency to Fe-limitation. Biological fractionation of Fe isotopes was determined by comparing δ56Fe of phytoplankton to the media. The use of a cell wash allows us to distinguish between isotopic fractionation during extracellular adsorption and intracellular uptake. The biological fractionation of Fe isotopes is highly dependent on culture conditions with Δδ56Fe ranging from +0.6 ‰ to -0.5 ‰ depending on ligand composition, species, and Fe-limitation status. Isotope effects for chemical, electrochemical, and photochemical reduction of Fe(III) to Fe(II) span an even larger range. For example, chemical reduction of Fe(III)-EDTA with hydroxylamine hydrochloride has an isotope effect of Δδ56Fe = -2.8 ‰. By contrast, photochemical reduction of Fe(III)-EDTA has an isotope effect of Δδ56Fe = +0.9 ‰. Isotope effects for electrochemical reduction of Fe(III) using a rotating disc electrode allow for greater control of experimental conditions, such as differentiating between the effects of electric potential (voltage) and mass transport (diffusion
Fractional Solutions of Bessel Equation with N-Method
Erdal Bas; Resat Yilmazer; Etibar Panakhov
2013-01-01
This paper deals with the design fractional solution of Bessel equation. We obtain explicit solutions of the equation with the help of fractional calculus techniques. Using the N-fractional calculus operator N ν method, we derive the fractional solutions of the equation.
Method for Attaining Caraway Seed Oil Fractions with Different Composition.
Shiwakoti, Santosh; Poudyal, Shital; Saleh, Osama; Astatkie, Tess; Zheljazkov, Valtcho D
2016-06-01
Caraway (Carum carvi L.) is a medicinal and aromatic plant; its seeds (fruits) are used as spice and they contain essential oils. We hypothesized that by collecting caraway oil at different time points during the extraction process, we could obtain oil fractions with distinct chemical composition. A hydrodistillation time (HDT) study was conducted to test the hypothesis. The caraway seed oil fractions were collected at eight different HDT (at 0 - 2, 2 - 7, 7 - 15, 15 - 30, 30 - 45, 45 - 75, 75 - 105, and 105 - 135 min). Additionally, a non-stop HD for 135 min was conducted as a control. Most of the oil was eluted early in the HD process. The non-stop HDT treatment yielded 2.76% oil by weight. Of the 24 essential oil constituents, limonene (77 - 19% of the total oil) and carvone (20 - 79%) were the major ones. Other constituents included myrcene (0.72 - 0.16%), trans-carveol (0.07 - 0.39%), and β-caryophyllene (0.07 - 0.24%). Caraway seed oil with higher concentration of limonene can be obtained by sampling oil fractions early in HD process; conversely, oil with high concentration of carvone can be obtained by excluding the fractions eluted early in the HD process. We demonstrated a method of obtaining caraway seed oil fractions with various and unique composition. These novel oil fractions with unique composition are not commercially available and could have much wider potential uses, and also target different markets compared to the typical caraway essential oil. PMID:27119969
Chemical fractionation of some natural radionuclides in a soil contaminated by slags
International Nuclear Information System (INIS)
To investigate the chemical fractionation of 238U, 226Ra, 210Pb, and 228Ra in soils contaminated by slags from coal firing and from pyrite roasting, a sequential extraction method (modified Tessier procedure) has been applied. The following fractions were each extracted: 1, easily exchangeable; 2, bound to carbonates; 3, bound to iron-manganese oxides; 4; bound to organic matter; 5, persistently bound; 6, residual. In addition, the extractants were also analyzed for the insoluble matrix elements Al and Fe to provide some information on the effect of each extraction step on the dissolution of the matrix. The results show that the percentage amounts of these radio-nuclide in fractions 1 (238U and 210Pb released from the slag by the iron-manganese oxide extractant are subsequently reabsorbed rapidly to a considerable extent by soil minerals and thus do not appear in the iron-manganese oxide fraction 3 but rather in fractions 4 and 6. As a result of such redistribution processes, it will be almost impossible to predict quantitatively the chemical fractionation of radionuclides in contaminated soils by investigating pure slags only. 24 refs., 2 figs., 2 tabs
International Nuclear Information System (INIS)
Several physical and chemical parameters of sediment extraction and fractionation of organic compounds that influence bioassay results were evaluated. Each parameter was evaluated with a photoluminescent bacterial bioassay (Microtox) as an end point. Three solvents (acetonitrile, acetone, and methanol) were studied for their ability to extract toxic organic components from marine sediments. Acetone extracted the most toxicity, with no difference between acetonitrile and methanol. Two methods of fractionating sediment extracts (silica-gel-column chromatography (SGCC) and acid-base fractionation) were compared. SGCC was more useful because it resulted in a wider range of responses and was faster to perform than acid-base fractionation. Microtox was used to rank four marine sediments with respect to toxicity and to determine if one chemical class (or fraction) was consistently more toxic among different sediments. With some caveats, Microtox results agreed with general chemical concentration trends and other bioassay results in distinguishing between contaminated and noncontaminated sediments. Although results indicated there was not a consistently most toxic fraction among sediments, there was a consistently least toxic fraction. The effect of sediment storage time on toxicity was also evaluated. Results indicated that the most stable chemical fraction (containing nonpolar hydrocarbons) did not change toxicologically for 30 weeks, whereas the more chemically active fraction (containing ketones, quinones, and carboxyls) changed as soon as one week
DNA sequencing: chemical methods
International Nuclear Information System (INIS)
Limited base-specific or base-selective cleavage of a defined DNA fragment yields polynucleotide products, the length of which correlates with the positions of the particular base (or bases) in the original fragment. Sverdlov and co-workers recognized the possibility of using this principle for the determination of DNA sequences. In 1977 a fully elaborated method was introduced based on this principle, which allowed routine analysis of DNA sequences over distances greater than 100 nucleotide unite from a defined, radiolabeled terminus. Six procedures for partial cleavage were described. Simultaneous parallel resolution of an appropriate set of partial cleavage mixtures by polyacrylamide gel electrophoresis, followed by visualization of the radioactive bands by autoradiography, allows the deduction of nucleotide sequence
International Nuclear Information System (INIS)
In this Letter, a generalized fractional sub-equation method is proposed for solving fractional differential equations with variable coefficients. Being concise and straightforward, this method is applied to the space–time fractional Gardner equation with variable coefficients. As a result, many exact solutions are obtained including hyperbolic function solutions, trigonometric function solutions and rational solutions. It is shown that the considered method provides a very effective, convenient and powerful mathematical tool for solving many other fractional differential equations in mathematical physics. -- Highlights: ► Study of fractional differential equations with variable coefficients plays a role in applied physical sciences. ► It is shown that the proposed algorithm is effective for solving fractional differential equations with variable coefficients. ► The obtained solutions may give insight into many considerable physical processes.
Energy Technology Data Exchange (ETDEWEB)
Tang, Bo, E-mail: tangbo08@yahoo.cn [School of Mathematics and Statistics, Xi' an Jiaotong University, Xi' an 710049 (China); He, Yinnian [School of Mathematics and Statistics, Xi' an Jiaotong University, Xi' an 710049 (China); College of Mathematics Sciences, Xinjiang Normal University, Urumqi, Xinjiang 830054 (China); Wei, Leilei, E-mail: leileiwei09@gmail.com [School of Mathematics and Statistics, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Xindong [College of Mathematics Sciences, Xinjiang Normal University, Urumqi, Xinjiang 830054 (China)
2012-08-06
In this Letter, a generalized fractional sub-equation method is proposed for solving fractional differential equations with variable coefficients. Being concise and straightforward, this method is applied to the space–time fractional Gardner equation with variable coefficients. As a result, many exact solutions are obtained including hyperbolic function solutions, trigonometric function solutions and rational solutions. It is shown that the considered method provides a very effective, convenient and powerful mathematical tool for solving many other fractional differential equations in mathematical physics. -- Highlights: ► Study of fractional differential equations with variable coefficients plays a role in applied physical sciences. ► It is shown that the proposed algorithm is effective for solving fractional differential equations with variable coefficients. ► The obtained solutions may give insight into many considerable physical processes.
Zayernouri, Mohsen; Matzavinos, Anastasios
2016-07-01
We first formulate a fractional class of explicit Adams-Bashforth (A-B) and implicit Adams-Moulton (A-M) methods of first- and second-order accuracy for the time-integration of t τ 0 CD u (x,t) = g (t ; u), τ ∈ (0 , 1 ], where t τ 0 CD denotes the fractional derivative in the Caputo sense. In this fractional setting and in contrast to the standard Adams methods, an extra history load term emerges and the associated weight coefficients are τ-dependent. However when τ = 1, the developed schemes reduce to the well-known A-B and A-M methods with standard coefficients. Hence, in terms of scientific computing, our approach constitutes a minimal modification of the existing Adams libraries. Next, we develop an implicit-explicit (IMEX) splitting scheme for linear and nonlinear fractional PDEs of a general advection-reaction-diffusion type, and we apply our scheme to the time-space fractional Keller-Segel chemotaxis system. In this context, we evaluate the nonlinear advection term explicitly, employing the fractional A-B method in the prediction step, and we treat the corresponding diffusion term implicitly in the correction step using the fractional A-M scheme. Moreover, we perform the corresponding spatial discretization by employing an efficient and spectrally-accurate fractional spectral collocation method. Our numerical experiments exhibit the efficiency of the proposed IMEX scheme in solving nonlinear fractional PDEs.
Directory of Open Access Journals (Sweden)
Emad A.-B. Abdel-Salam
2013-01-01
Full Text Available The fractional Riccati expansion method is proposed to solve fractional differential equations. To illustrate the effectiveness of the method, space-time fractional Korteweg-de Vries equation, regularized long-wave equation, Boussinesq equation, and Klein-Gordon equation are considered. As a result, abundant types of exact analytical solutions are obtained. These solutions include generalized trigonometric and hyperbolic functions solutions which may be useful for further understanding of the mechanisms of the complicated nonlinear physical phenomena and fractional differential equations. Among these solutions, some are found for the first time. The periodic and kink solutions are founded as special case.
Chemical oxygen demand (COD) fractions characterization of Karachi metropolitan wastewater
International Nuclear Information System (INIS)
To prove the hypothesis that the inert products are given to environment due to biological degradation of substrate in activated sludge operations. This study was design to investigate the inert fractions of chemical oxygen demand (COD) in metropolitan effluent. An aerobic batch reactor system was experimentally setup and maintained up to 480 hours. At the end of operations, COD compositions of metropolitan wastewater were found to be STO = 131 mg/L, XSO = 63 mg/L, CSO = 178 mg/L, SSO = 115 mg/L, SI = 16 mg/L, XI 218 mg/L, respectively. At the end of operations, COD compositions of metropolitan wastewater were found to be STO = 131 mg/L, XSO = 63 mg/L, CSO 178 mg/L, SSO = 115 mg/L, SI = 16 mg/L, XI = 218 mg/L respectively. This study is focused on inert COD fractions of metropolitan wastewater which consist of domestic as well as local industrial effluent. Soluble inert COD (SI) must be determined for discharge standards since it did not give any reaction in activated sludge system and was given with wastewater discharge. However particulate inert COD (XI) accumulated in system depending on sludge retention time due to it is only wasted from system by wasted sludge. Experimental techniques were used attained Zohu X. et al. [1, 2] in order to determine directly influent particulate and soluble inert fractions. The experimental study was carried out until COD profile reached to steady state or depletion of degradable substrate. The conventional parameters of municipal characterization were as follows: total COD (CTO) = 412 mg/L, total soluble COD (STO) = 131 mg/L, biochemical oxygen demand (BOD5) = 197 mg/L, total biochemical oxygen demand (BODt) = 351 mg/L, total suspended solids (TSS) = 264 mg/L, ammonia nitrogen (NH/sub 3/-N) = 26.6 mg/L, grease and oil (G and O) = 17.5 mg/L and pH were 7.4 SU, respectively. (author)
Indian Academy of Sciences (India)
S Panda; B K Panda
2010-09-01
Chemical potential and internal energy of a noninteracting Fermi gas at low temperature are evaluated using the Sommerfeld method in the fractional-dimensional space. When temperature increases, the chemical potential decreases below the Fermi energy for any dimension equal to 2 and above due to the small entropy, while it increases above the Fermi energy for dimensions below 2 as a result of high entropy. The ranges of validity of the truncated series expansions of these quantities are extended from low to intermediate temperature regime as well as from high to relatively low density regime by using the Pad ́e approximant technique.
2014-01-01
The paper uses the Local fractional variational Iteration Method for solving the second kind Volterra integro-differential equations within the local fractional integral operators. The analytical solutions within the non-differential terms are discussed. Some illustrative examples will be discussed. The obtained results show the simplicity and efficiency of the present technique with application to the problems for the integral equations.
Chemical microreactor and method thereof
Energy Technology Data Exchange (ETDEWEB)
Morse, Jeffrey D. (Martinez, CA); Jankowski, Alan (Livermore, CA)
2011-08-09
A method for forming a chemical microreactor includes forming at least one capillary microchannel in a substrate having at least one inlet and at least one outlet, integrating at least one heater into the chemical microreactor, interfacing the capillary microchannel with a liquid chemical reservoir at the inlet of the capillary microchannel, and interfacing the capillary microchannel with a porous membrane near the outlet of the capillary microchannel, the porous membrane being positioned beyond the outlet of the capillary microchannel, wherein the porous membrane has at least one catalyst material imbedded therein.
On an explicit finite difference method for fractional diffusion equations
S. B. Yuste; Acedo, L.
2003-01-01
A numerical method to solve the fractional diffusion equation, which could also be easily extended to many other fractional dynamics equations, is considered. These fractional equations have been proposed in order to describe anomalous transport characterized by non-Markovian kinetics and the breakdown of Fick's law. In this paper we combine the forward time centered space (FTCS) method, well known for the numerical integration of ordinary diffusion equations, with the Grunwald-Letnikov defin...
Variational Iteration Method for a Fractional-Order Brusselator System
Directory of Open Access Journals (Sweden)
H. Jafari
2014-01-01
Full Text Available This paper presents approximate analytical solutions for the fractional-order Brusselator system using the variational iteration method. The fractional derivatives are described in the Caputo sense. This method is based on the incorporation of the correction functional for the equation. Two examples are solved as illustrations, using symbolic computation. The numerical results show that the introduced approach is a promising tool for solving system of linear and nonlinear fractional differential equations.
A NUMERICAL METHOD FOR FRACTIONAL INTEGRAL WITH APPLICATIONS
Institute of Scientific and Technical Information of China (English)
朱正佑; 李根国; 程昌钧
2003-01-01
A new numerical method for the fractional integral that only stores part history data is presented, and its discretization error is estimated. The method can be used to solve the integro-differential equation including fractional integral or fractional derivative in a long history. The difficulty of storing all history data is overcome and the error can be controlled. As application, motion equations governing the dynamical behavior of a viscoelastic Timoshenko beam with fractional derivative constitutive relation are given. The dynamical response of the beam subjected to a periodic excitation is studied by using the separation variables method Then the new numerical method is used to solve a class of weakly singular Volterra integro-differential equations which are applied to describe the dynamical behavior of viscoelastic beams with fractional derivative constitutive relations. The analytical and unmerical results are compared. It is found that they are very close.
Identification of fractional order systems using modulating functions method
Liu, Dayan
2013-06-01
The modulating functions method has been used for the identification of linear and nonlinear systems. In this paper, we generalize this method to the on-line identification of fractional order systems based on the Riemann-Liouville fractional derivatives. First, a new fractional integration by parts formula involving the fractional derivative of a modulating function is given. Then, we apply this formula to a fractional order system, for which the fractional derivatives of the input and the output can be transferred into the ones of the modulating functions. By choosing a set of modulating functions, a linear system of algebraic equations is obtained. Hence, the unknown parameters of a fractional order system can be estimated by solving a linear system. Using this method, we do not need any initial values which are usually unknown and not equal to zero. Also we do not need to estimate the fractional derivatives of noisy output. Moreover, it is shown that the proposed estimators are robust against high frequency sinusoidal noises and the ones due to a class of stochastic processes. Finally, the efficiency and the stability of the proposed method is confirmed by some numerical simulations.
Devices, systems, and methods for microscale isoelectric fractionation
Energy Technology Data Exchange (ETDEWEB)
Sommer, Gregory J.; Hatch, Anson V.; Wang, Ying-Chih; Singh, Anup K.
2016-08-09
Embodiments of the present invention provide devices, systems, and methods for microscale isoelectric fractionation. Analytes in a sample may be isolated according to their isoelectric point within a fractionation microchannel. A microfluidic device according to an embodiment of the invention includes a substrate at least partially defining a fractionation microchannel. The fractionation microchannel has at least one cross-sectional dimension equal to or less than 1 mm. A plurality of membranes of different pHs are disposed in the microchannel. Analytes having an isoelectric point between the pH of the membranes may be collected in a region of the fractionation channel between the first and second membranes through isoelectric fractionation.
Devices, systems, and methods for microscale isoelectric fractionation
Sommer, Gregory J; Hatch, Anson V; Wang, Ying-Chih; Singh, Anup K
2015-04-14
Embodiments of the present invention provide devices, systems, and methods for microscale isoelectric fractionation. Analytes in a sample may be isolated according to their isoelectric point within a fractionation microchannel. A microfluidic device according to an embodiment of the invention includes a substrate at least partially defining a fractionation microchannel. The fractionation microchannel has at least one cross-sectional dimension equal to or less than 1 mm. A plurality of membranes of different pHs are disposed in the microchannel. Analytes having an isoelectric point between the pH of the membranes may be collected in a region of the fractionation channel between the first and second membranes through isoelectric fractionation.
Directory of Open Access Journals (Sweden)
Ammar Ali Neamah
2014-01-01
Full Text Available The paper uses the Local fractional variational Iteration Method for solving the second kind Volterra integro-differential equations within the local fractional integral operators. The analytical solutions within the non-differential terms are discussed. Some illustrative examples will be discussed. The obtained results show the simplicity and efficiency of the present technique with application to the problems for the integral equations.
Wavelets method for the time fractional diffusion-wave equation
Energy Technology Data Exchange (ETDEWEB)
Heydari, M.H., E-mail: heydari@stu.yazd.ac.ir [Faculty of Mathematics, Yazd University, Yazd (Iran, Islamic Republic of); The Laboratory of Quantum Information Processing, Yazd University, Yazd (Iran, Islamic Republic of); Hooshmandasl, M.R., E-mail: hooshmandasl@yazd.ac.ir [Faculty of Mathematics, Yazd University, Yazd (Iran, Islamic Republic of); The Laboratory of Quantum Information Processing, Yazd University, Yazd (Iran, Islamic Republic of); Maalek Ghaini, F.M., E-mail: maalek@yazd.ac.ir [Faculty of Mathematics, Yazd University, Yazd (Iran, Islamic Republic of); The Laboratory of Quantum Information Processing, Yazd University, Yazd (Iran, Islamic Republic of); Cattani, C., E-mail: ccattani@unisa.it [Department of Mathematics, University of Salerno, Fisciano (Italy)
2015-01-23
In this paper, an efficient and accurate computational method based on the Legendre wavelets (LWs) is proposed for solving the time fractional diffusion-wave equation (FDWE). To this end, a new fractional operational matrix (FOM) of integration for the LWs is derived. The LWs and their FOM of integration are used to transform the problem under consideration into a linear system of algebraic equations, which can be simply solved to achieve the solution of the problem. The proposed method is very convenient for solving such problems, since the initial and boundary conditions are taken into account automatically. - Highlights: • A new operational matrix of fractional integration for the LWs is derived. • A new method based on the LWs is proposed for the time FDWE. • The paper contains some useful properties of the LWs. • The proposed method can be applied for fractional sub-diffusion systems. • The proposed method can be extended for fourth-order FDWE.
Robust fractional order differentiators using generalized modulating functions method
Liu, Dayan
2015-02-01
This paper aims at designing a fractional order differentiator for a class of signals satisfying a linear differential equation with unknown parameters. A generalized modulating functions method is proposed first to estimate the unknown parameters, then to derive accurate integral formulae for the left-sided Riemann-Liouville fractional derivatives of the studied signal. Unlike the improper integral in the definition of the left-sided Riemann-Liouville fractional derivative, the integrals in the proposed formulae can be proper and be considered as a low-pass filter by choosing appropriate modulating functions. Hence, digital fractional order differentiators applicable for on-line applications are deduced using a numerical integration method in discrete noisy case. Moreover, some error analysis are given for noise error contributions due to a class of stochastic processes. Finally, numerical examples are given to show the accuracy and robustness of the proposed fractional order differentiators.
Wavelet Methods for Solving Fractional Order Differential Equations
Directory of Open Access Journals (Sweden)
A. K. Gupta
2014-01-01
Full Text Available Fractional calculus is a field of applied mathematics which deals with derivatives and integrals of arbitrary orders. The fractional calculus has gained considerable importance during the past decades mainly due to its application in diverse fields of science and engineering such as viscoelasticity, diffusion of biological population, signal processing, electromagnetism, fluid mechanics, electrochemistry, and many more. In this paper, we review different wavelet methods for solving both linear and nonlinear fractional differential equations. Our goal is to analyze the selected wavelet methods and assess their accuracy and efficiency with regard to solving fractional differential equations. We discuss challenges faced by researchers in this field, and we emphasize the importance of interdisciplinary effort for advancing the study on various wavelets in order to solve differential equations of arbitrary order.
Andreou, K.; Jones, K.; Semple, K.
2009-04-01
Distribution of pesticide non extractable residues resulted from the incubation of two natural soils with each of the isoproturon, diazinon and cypermethrin pesticide was assessed in this study. Pesticide non extractable residues distribution in soil physical and chemical fractions is known to ultimately affect their fate. This study aimed to address the fate and behaviour of the non extractable residues in the context of their association with soil physical and chemical fractions with varying properties and characteristics. Non extractable residues were formed from incubation of each pesticide in the two natural soils over a period of 24 months. Soils containing the non extractable residues were fractionated into three solid phase fractions using a physical fractionation procedure as follows: Sediment (SED, >20 μm), (II) Microaggregate (MA, 20-2 μm) and (III) Colloid phase (COL, 2-0.05 μm). Each soil fraction was then fractionated into organic carbon chemical fractionations as follows: Fulvic acid (FA), Humic acid (HA) and Humin (HM). Significant amount of the pesticides was lost during the incubation period. Enrichment factors for the organic carbon and the 14C-pesticide residues were higher in the MA and COL fraction rather than the SED fraction. Greater association and enrichment of the fulvic acid fraction of the organic carbon in the soil was observed. Non extractable residues at the FA fraction showed to diminish while in the HA fraction were increased with decreasing the fraction size. An appreciable amount of non extractable residues were located in the HM fraction but this was less than the amount recovered in the humic substances. Long term fate of pesticide non extractable residues in the soil structural components is important in order to assess any risk associated with them.
Solutions of fractional diffusion equations by variation of parameters method
Directory of Open Access Journals (Sweden)
Mohyud-Din Syed Tauseef
2015-01-01
Full Text Available This article is devoted to establish a novel analytical solution scheme for the fractional diffusion equations. Caputo’s formulation followed by the variation of parameters method has been employed to obtain the analytical solutions. Following the derived analytical scheme, solution of the fractional diffusion equation for several initial functions has been obtained. Graphs are plotted to see the physical behavior of obtained solutions.
Chemical Fractionation in the Silicate Vapor Atmosphere of the Earth
Pahlevan, Kaveh; Eiler, John; 10.1016/j.epsl.2010.10.03
2010-01-01
Despite its importance to questions of lunar origin, the chemical composition of the Moon is not precisely known. In recent years, however, the isotopic composition of lunar samples has been determined to high precision and found to be indistinguishable from the terrestrial mantle despite widespread isotopic heterogeneity in the Solar System. In the context of the giant-impact hypothesis, this level of isotopic homogeneity can evolve if the proto-lunar disk and post-impact Earth undergo turbulent mixing into a single uniform reservoir while the system is extensively molten and partially vaporized. In the absence of liquid-vapor separation, such a model leads to the lunar inheritance of the chemical composition of the terrestrial magma ocean. Hence, the turbulent mixing model raises the question of how chemical differences arose between the silicate Earth and Moon. Here we explore the consequences of liquid-vapor separation in one of the settings relevant to the lunar composition: the silicate vapor atmosphere...
Directory of Open Access Journals (Sweden)
Yosvany Díaz Domínguez
2014-03-01
Full Text Available The hydrolysis of the macromolecules that compose the organic fraction of municipal solid waste canbe taken for chemical, physical and biological methods, having all as aim the unfolding of the complexmolecules in simplier monomer. Thereby the degradation of organic matter is enhanced and resultsmore efficient the process of biogas via anaerobic. Chemical pretreatments were employed in the workusing sodium hydroxide (NaOH and hydrogen peroxide (H2O2 as reagents.The soluble chemicaloxygen demand (COD, the maximum methane yield and the methane rates production were used toevaluate the pretreatment actions. The degradation of the waste was able to be increased by allowinga comparative analysis to determine the best working conditions for this stage and subsequently itsimpact in the generation of biogas, methane specifically.
Extensions and results from a method for evaluating fractional integrals
International Nuclear Information System (INIS)
A method has been derived from Laplace transform that enables the evaluation of Weyl fractional integrals by transforming them into known integrals. This method is adapted and extended in a variety of ways to demonstrate the utility of the method in deriving alternative representations for other classes of integrals. The authors utilised the Feynman integral of quantum electrodynamics and found that they could develop more sophisticated results from this integral, which are given in Appendix C. A list of various fractional integrals evaluated by this technique is presented in Appendix A. 15 refs
Fractional domain varying-order differential denoising method
Zhang, Yan-Shan; Zhang, Feng; Li, Bing-Zhao; Tao, Ran
2014-10-01
Removal of noise is an important step in the image restoration process, and it remains a challenging problem in image processing. Denoising is a process used to remove the noise from the corrupted image, while retaining the edges and other detailed features as much as possible. Recently, denoising in the fractional domain is a hot research topic. The fractional-order anisotropic diffusion method can bring a less blocky effect and preserve edges in image denoising, a method that has received much interest in the literature. Based on this method, we propose a new method for image denoising, in which fractional-varying-order differential, rather than constant-order differential, is used. The theoretical analysis and experimental results show that compared with the state-of-the-art fractional-order anisotropic diffusion method, the proposed fractional-varying-order differential denoising model can preserve structure and texture well, while quickly removing noise, and yields good visual effects and better peak signal-to-noise ratio.
Chemical Fractionation in the Silicate Vapor Atmosphere of the Earth
Pahlevan, Kaveh; Stevenson, David; Eiler, John
2010-01-01
Despite its importance to questions of lunar origin, the chemical composition of the Moon is not precisely known. In recent years, however, the isotopic composition of lunar samples has been determined to high precision and found to be indistinguishable from the terrestrial mantle despite widespread isotopic heterogeneity in the Solar System. In the context of the giant-impact hypothesis, this level of isotopic homogeneity can evolve if the proto-lunar disk and post-impact Earth undergo turbu...
Review of experimental methods for evaluating effective delayed neutron fraction
Energy Technology Data Exchange (ETDEWEB)
Yamane, Yoshihiro [Nagoya Univ. (Japan). School of Engineering
1997-03-01
The International Effective Delayed Neutron Fraction ({beta}{sub eff}) Benchmark Experiments have been carried out at the Fast Critical Assembly of Japan Atomic Energy Research Institute since 1995. Researchers from six countries, namely France, Italy, Russia, U.S.A., Korea, and Japan, participate in this FCA project. Each team makes use of each experimental method, such as Frequency Method, Rossi-{alpha} Method, Nelson Number Method, Cf Neutron Source Method, and Covariance Method. In this report these experimental methods are reviewed. (author)
Institute of Scientific and Technical Information of China (English)
Risto PÖYKIÖ; Hannu NURMESNIEMI; Olli DAHL; Mikko MÄKELÄ
2014-01-01
The aim of this study was to extract the biomass-based bottom and fly ash fractions by a three-stage fractionation method for water-soluble (H2O), ammonium-acetate (CH3COONH4) and hydrochloric acid (HCl) fractions in order to access the leaching behaviour of these residues. Except for Mo, S, Na and elements whose concentrations were lower than the detection limits, the extractable element concentrations in both ash fractions followed the order H2O
Understanding the solid phase chemical fractionation of uranium in soil and effect of ageing.
Rout, Sabyasachi; Kumar, Ajay; Ravi, P M; Tripathi, R M
2016-11-01
The aim of the present work is to understand the solid phase chemical fractionation of Uranium (U) in soil and the mechanism involved. This study integrated batch experiments of U(VI) adsorption to soil, study of U in different soil fractions, ageing impact on fractionation of U and spectroscopic investigation of adsorbed U(VI) using X-ray Photoelectron Spectroscopy (XPS). For the study three soils, pedogenically different (S1: Igneous, S2: Sedimentary and S3: Metamorphic) were amended with U(VI) and chemical fractionation of U was studied by sequential extraction after an interval of one month and 12 months. It was found that there occurs a significant rearrangement of U in different fractions with ageing and no correlation was observed between the U content in different fractions and the adsorbents of respective fractions such as soil organic matter (SOM), Fe/Mn oxides (hydroxides) carbonates, soil cation exchange capacity (CEC). XPS study revealed that surface enrichment of U mainly governed by the carbonate minerals and SOM, whereas bulk concentration was controlled by the oxides (hydroxides) of Si and Al. Occlusion of U-Fe-oxides (hydroxides) on silica was identified as an important mechanism for bulk enrichment (Increase in residual fraction) and depletion of U concentration in reducible fraction. PMID:27322903
International Nuclear Information System (INIS)
To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon (14C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of 14C abundances showed that (1) bomb-derived 14C has penetrated the first 16 cm mineral soil at least; (2) Δ14C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived 14C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived 14C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales
Wang, Nina Ching Y.; Glenn E. Rice; Teuschler, Linda K.; Joan Colman; Yang, Raymond S.H.
2012-01-01
Both the Massachusetts Department of Environmental Protection (MADEP) and the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG) developed fraction-based approaches for assessing human health risks posed by total petroleum hydrocarbon (TPH) mixtures in the environment. Both organizations defined TPH fractions based on their expected environmental fate and by analytical chemical methods. They derived toxicity values for selected compounds within each fraction and used these as surroga...
Comparison of fractionation methods for nitrogen and starch in maize and grass silages.
Ali, M; de Jonge, L H; Cone, J W; van Duinkerken, G; Blok, M C; Bruinenberg, M H; Hendriks, W H
2016-06-01
In in situ nylon bag technique, many feed evaluation systems use a washing machine method (WMM) to determine the washout (W) fraction and to wash the rumen incubated nylon bags. As this method has some disadvantages, an alternate modified method (MM) was recently introduced. The aim of this study was to determine and compare the W and non-washout (D+U) fractions of nitrogen (N) and/or starch of maize and grass silages, using the WMM and the MM. Ninety-nine maize silage and 99 grass silage samples were selected with a broad range in chemical composition. The results showed a large range in the W, soluble (S) and D+U fractions of N of maize and grass silages and the W, insoluble washout (W-S) and D+U fractions of starch of maize silages, determined by both methods, due to variation in their chemical composition. The values for N fractions of maize and grass silages obtained with both methods were found different (p silages which might be due to different methodological approaches, such as different rinsing procedures (washing vs. shaking), duration of rinsing (40 min vs. 60 min) and different solvents (water vs. buffer solution). The large differences (p < 0.001) in the W-S and D+U fractions of starch determined with both methods can led to different predicted values for the effective rumen starch degradability. In conclusion, the MM with one recommended shaking procedure, performed under identical and controlled experimental conditions, can give more reliable results compared to the WMM, using different washing programs and procedures. PMID:26331458
Lattice Boltzmann method for the fractional advection-diffusion equation
Zhou, J. G.; Haygarth, P. M.; Withers, P. J. A.; Macleod, C. J. A.; Falloon, P. D.; Beven, K. J.; Ockenden, M. C.; Forber, K. J.; Hollaway, M. J.; Evans, R.; Collins, A. L.; Hiscock, K. M.; Wearing, C.; Kahana, R.; Villamizar Velez, M. L.
2016-04-01
Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β , the fractional order α , and the single relaxation time τ , the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering.
A General Method for Designing Fractional Order PID Controller
Directory of Open Access Journals (Sweden)
Marzieh Safaei
2013-01-01
Full Text Available The idea of using fractional order calculus in control became apparent when this kind of calculus was accepted as a powerful tool in many applications. This resulted in a new generation of PID controller called fractional order PID Controller, named as Controller. controller is more flexible and provides a better response with larger stability region as compared with standard PID controller. This paper presents a simple and reliable method for finding the family of controllers. The required calculations are done in frequency domain based on frequency response of the system and the stability region is specified in the parameters space. This method can be used for time-delay systems and, more generally, for any system with no transfer function.
Directory of Open Access Journals (Sweden)
Tales Tiecher
2014-10-01
Full Text Available Phosphate release kinetics from manures are of global interest because sustainable plant nutrition with phosphate will be a major concern in the future. Although information on the bioavailability and chemical composition of P present in manure used as fertilizer are important to understand its dynamics in the soil, such studies are still scarce. Therefore, P extraction was evaluated in this study by sequential chemical fractionation, desorption with anion-cation exchange resin and 31P nuclear magnetic resonance (31P-NMR spectroscopy to assess the P forms in three different dry manure types (i.e. poultry, cattle and swine manure. All three methods showed that the P forms in poultry, cattle and swine dry manures are mostly inorganic and highly bioavailable. The estimated P pools showed that organic and recalcitrant P forms were negligible and highly dependent on the Ca:P ratio in manures. The results obtained here showed that the extraction of P with these three different methods allows a better understanding and complete characterization of the P pools present in the manures.
Array processors based on Gaussian fraction-free method
Energy Technology Data Exchange (ETDEWEB)
Peng, S.; Sedukhin, S. [Aizu Univ., Aizuwakamatsu, Fukushima (Japan); Sedukhin, I.
1998-03-01
The design of algorithmic array processors for solving linear systems of equations using fraction-free Gaussian elimination method is presented. The design is based on a formal approach which constructs a family of planar array processors systematically. These array processors are synthesized and analyzed. It is shown that some array processors are optimal in the framework of linear allocation of computations and in terms of number of processing elements and computing time. (author)
A method for detecting the presence of organic fraction in nucleation mode sized particles
Vaattovaara, P.; Räsänen, M.; Kühn, T.; Joutsensaari, J.; Laaksonen, a
2005-01-01
New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm) and the lower end of Aitken mode particles (d≤50 nm) is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer) method to shed light on the presence of organic fraction in the nucleation mode size class in differ...
Chemical reaction and separation method
Jansen, J.C.; Kapteijn, F.; Strous, S.A.
2005-01-01
The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu
Experimental facility and void fraction calibration methods for impedance probes
International Nuclear Information System (INIS)
An experimental facility was designed and constructed with aims of to calibrate a capacitance probe for gas-liquid flow void fraction measurements. The facility is composed of a metallic hack with a vertical 2,300 mm high glass tube with 38 mm ID with stagnant water and compressed air bubbling system simulating the gas phase (vapor). At the lower part, a mixing section with a porous media element releases the air bubbles into the water, and the compressed air flow is measured by two calibrated rotameters. At the upper part a stagnant water tank separates the liquid and gas. Two pressure taps are located near the lower and upper sides of the glass tube for pressure difference measurement. The pressure difference is used for low void fraction values (0-15%) calibration methods, as described in the work. Two electrically controlled quick closing valves are installed between the porous media element and the upward separation tank for high void fraction values measurement (15-50%) used to calibrate the capacitance probe. The experimental facility design, construction, capacitance probe calibration methods and results, as well as flow pattern visualization, are presented. Finally, the capacitance probe will be installed on a natural circulation circuit mounted at the Nuclear Engineering Center (CEN/IPEN/CNEN-SP) for measurement of the instantaneous bulk void. Instantaneous signals generated by the capacitance probe will allow the determination of natural circulation loop global energy balance. (author)
Intelligent numerical methods II applications to multivariate fractional calculus
Anastassiou, George A
2016-01-01
In this short monograph Newton-like and other similar numerical methods with applications to solving multivariate equations are developed, which involve Caputo type fractional mixed partial derivatives and multivariate fractional Riemann-Liouville integral operators. These are studied for the first time in the literature. The chapters are self-contained and can be read independently. An extensive list of references is given per chapter. The book’s results are expected to find applications in many areas of applied mathematics, stochastics, computer science and engineering. As such this short monograph is suitable for researchers, graduate students, to be used in graduate classes and seminars of the above subjects, also to be in all science and engineering libraries.
Chemical Nature and Turnover of Carbon Associated with Diagnostic Aggregate Fractions
Six, J.
2004-12-01
Recently, many studies have shown the importance of aggregation in controlling soil organic C dynamics and storage. Nevertheless, very few studies have characterized the chemical nature of aggregated associated C fractions to elucidate the origin and degree of microbial alteration of these C fractions. Here, I summarize several studies employing biomarker analyses for plant-derived lignin, bacterial-derived muramic acid, and fungal-derived glucosamine to aggregate associated C fractions. A comparison of different particulate organic matter (POM) fractions indicated that fine POM occluded within microaggregates-within-macroaggregates (mM) had the greatest amino sugar content, greatest ratio of glucosamine over muramic acid, and lowest phenolic CuO oxidation products. The latter result suggest that the fine POM is the most degraded POM fraction, which was confirmed by C isotope analyses. However, side chain oxidation of lignin compounds of fine POM was intermediate, suggesting an average microbial alteration of lignin. These results suggest a significant microbial contribution, especially fungal, to this relative older C fraction protected within the mM. Carbon and isotopic analyses of the mM confirmed that this structural unit within the soil protects C from fast decomposition and facilitates the long-term stabilization of C in undisturbed soil. Furthermore, amino sugar analyses indicated that microbial-derived C is stabilized in the mM, due primarily to a greater fungal-mediated improvement of soil structural stability and concurrent deposition of fungal-derived C. In conclusion, the characterizing the chemical nature and turnover of aggregate associated C fractions elucidated that the mM fraction plays an important role in the long term stabilization of C and seems to be an ideal indicator or diagnostic fraction for C sequestration potential in soils.
Zhang, Leiyan; Geng, Jinju; Ding, Lili; Ren, Hongqiang
2012-01-01
This study highlighted the inorganic fractions in the extracellular polymeric substance (EPS) extract from two activated sludges and one biofilm. Nine EPS extraction methods (centrifugation, sonication, cation exchange resin (CER) + sonication, CER, heating, formaldehyde + heating, formaldehyde + NaOH, ethanol and EDTA) were used in the study. The EPS extracts had large inorganic fractions, which ranged from 28% to 94% of the EPS dry weight. The EPS inorganic fraction was dependent on the source of the sludge and wastewater, the kinds of bacteria and the extraction method. The EPS extracts obtained by heating and sonication had smaller inorganic fractions than those obtained by centrifugation. The compositions of the inorganic fraction of EPS extracts obtained with CER and sonication + CER showed similar trends. The chemical extraction methods could contaminate the inorganic composition of EPS extracts by impurities, carrying over of the extractant itself or by changing the pH of the solution. Ethanol was the most effective extractant for obtaining inorganic ions. PMID:22828296
Directory of Open Access Journals (Sweden)
Baojian Hong
2014-01-01
Full Text Available Based on He’s variational iteration method idea, we modified the fractional variational iteration method and applied it to construct some approximate solutions of the generalized time-space fractional Schrödinger equation (GFNLS. The fractional derivatives are described in the sense of Caputo. With the help of symbolic computation, some approximate solutions and their iterative structure of the GFNLS are investigated. Furthermore, the approximate iterative series and numerical results show that the modified fractional variational iteration method is powerful, reliable, and effective when compared with some classic traditional methods such as homotopy analysis method, homotopy perturbation method, adomian decomposition method, and variational iteration method in searching for approximate solutions of the Schrödinger equations.
Hong, Baojian; Lu, Dianchen
2014-01-01
Based on He's variational iteration method idea, we modified the fractional variational iteration method and applied it to construct some approximate solutions of the generalized time-space fractional Schrödinger equation (GFNLS). The fractional derivatives are described in the sense of Caputo. With the help of symbolic computation, some approximate solutions and their iterative structure of the GFNLS are investigated. Furthermore, the approximate iterative series and numerical results show that the modified fractional variational iteration method is powerful, reliable, and effective when compared with some classic traditional methods such as homotopy analysis method, homotopy perturbation method, adomian decomposition method, and variational iteration method in searching for approximate solutions of the Schrödinger equations. PMID:25276865
Quantification of chemical contaminants in the paper and board fractions of municipal solid waste.
Pivnenko, K; Olsson, M E; Götze, R; Eriksson, E; Astrup, T F
2016-05-01
Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies. PMID:26969284
Determination of iodine with chemical forms in rain water by fractional sampling/NAA
International Nuclear Information System (INIS)
A simple and rapid method has been developed for the fractional determination of particulate, iodide, iodate and non-ionic dissolved iodine in rain waters by using some filter technique and neutron activation analysis. The following procedure was chosen as a result of the tracer experiments. Particulate iodine in rain water (0.1-0.2l) is obtained as the residue on Millipore HAWP filter paper by filtration and determined by INAA. Iodide and iodate ion in half of the filtrate are adsorbed on Expapier F3 anion exchange filter papers and passed through the filter as non-ionic dissolved iodine which is then sealed into a plastic vial for irradiation. The iodate ion fraction is eluted with 15 ml of 0.5 M sodium hydroxide, and iodide ion and total ionic iodine (iodide + iodate) in another fraction are determined by the following method. The irradiated sample is decomposed together with an iodide carrier solution containing I-131 by heating in a sodium hypochlorite solution. After decomposition, the solution is acidified with hydrochloric acid, and the insoluble residue is filtered off. To the filtrate sodium sulfite solution and palladium chloride solution are added, and the precipitate of palladium iodide is separated with a glass fiber filter paper. Iodine contents of samples are calculated from the peak areas under the 443 keV γ-ray of I-128 in the precipitate and comparative standard. Corrections for chemical recovery are applied to them by means of the areas under 365 keV γ-ray of I-131. This method was applied to the rain water in Yokohama. The concentration of particulate, iodide, iodate and non-ionic dissolved iodine were 0.1-0.3, 1.0-3.7, 0.2-1.5 and 0-0.6 μg/l. The recovery of iodine in this procedure was about 70%. About 30 min was required for the radiochemical procedure and the limit of determination was 1 ng/l of iodine in a volume of 0.2l. (author)
An Adaptive Pseudospectral Method for Fractional Order Boundary Value Problems
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Mohammad Maleki
2012-01-01
Full Text Available An adaptive pseudospectral method is presented for solving a class of multiterm fractional boundary value problems (FBVP which involve Caputo-type fractional derivatives. The multiterm FBVP is first converted into a singular Volterra integrodifferential equation (SVIDE. By dividing the interval of the problem to subintervals, the unknown function is approximated using a piecewise interpolation polynomial with unknown coefficients which is based on shifted Legendre-Gauss (ShLG collocation points. Then the problem is reduced to a system of algebraic equations, thus greatly simplifying the problem. Further, some additional conditions are considered to maintain the continuity of the approximate solution and its derivatives at the interface of subintervals. In order to convert the singular integrals of SVIDE into nonsingular ones, integration by parts is utilized. In the method developed in this paper, the accuracy can be improved either by increasing the number of subintervals or by increasing the degree of the polynomial on each subinterval. Using several examples including Bagley-Torvik equation the proposed method is shown to be efficient and accurate.
Saha, Ray S.; Sahoo, S.
2015-01-01
In the present paper, we construct the analytical exact solutions of some nonlinear evolution equations in mathematical physics; namely the space-time fractional Zakharov—Kuznetsov (ZK) and modified Zakharov—Kuznetsov (mZK) equations by using fractional sub-equation method. As a result, new types of exact analytical solutions are obtained. The obtained results are shown graphically. Here the fractional derivative is described in the Jumarie' modified Riemann—Liouville sense.
Hrubik, Jelena; Glisic, Branka; Tubic, Aleksandra; Ivancev-Tumbas, Ivana; Kovacevic, Radmila; Samardzija, Dragana; Andric, Nebojsa; Kaisarevic, Sonja
2016-05-01
Absence of a municipal wastewater (WW) treatment plant results in the untreated WW discharge into the recipient. The present study investigated toxic effects and chemical composition of water extracts and fractions from untreated WW and recipient Danube River (DR). Samples were prepared by solid-phase extraction and silica gel fractionation and screened for EROD activity and cytotoxicity using aquatic models, comprising of fish liver cells (PLHC-1) and a model of the early development of zebrafish embryos, while rat (H4IIE) and human (HepG2) hepatoma cells served as mammalian models. Polar fraction caused cytotoxicity and increased the EROD activity in PLHC-1 cells, and increased mortality and developmental abnormalities in developing zebrafish embryos. In H4IIE, polar fraction induced inhibition of cell growth and increased EROD activity, whereas HepG2 exerted low or no response to the exposure. Non-polar and medium-polar fractions were ineffective. Tentative identification by GC/MS showed that WW is characterized by the hydrocarbons, alkylphenols, plasticizers, and a certain number of benzene derivatives and organic acids. In DR, smaller number of organic compounds was identified and toxicity was less pronounced than in WW treatments. The present study revealed the potent toxic effect of polar fraction of untreated WW, with biological responses varying in sensitivity across organisms. Obtained results confirmed that fraction- and species-specific toxicity should be considered when assessing health risk of environmental pollution. PMID:26829069
Panova, E. G.; Oleinikova, G. A.; Matinyan, N. N.; Bakhmatova, K. A.
2016-06-01
The behavior of some chemical elements was studied in soils and their liquid phase. Two reference soil profiles on glaciolacustrine clays (soddy-eluvial-metamorphic soil) and sands (soddy podzol) were investigated on the Russian Plain. A colloidal fraction (particles water from a soil sample of 30 g at the soil: water ratio of 1: 10. The suspension was mixed for 6 h, settled for 24 h, and filtrated using a membrane filter (water-soluble fraction (WSF) were analyzed by mass spectrometry with inductively coupled plasma. The chemical characteristics of the extracted liquid phase of the soil reflect its water-soluble component properties. The comparison of the data obtained with the results of the analysis for the whole soil allows assessment of a share of easily mobile and difficultly mobile forms of chemical compounds. This is the necessary basis for the development of a model describing the transport of metals in soil.
Evaluation of surviving fraction using nonclonogenic staining densitometry method
International Nuclear Information System (INIS)
This study was performed to compare our nonclonogenic survival assay (densitometry assay, DM assay) with the widely used clonogenic assay. The established cell lines (HaLa, RMUG, IMR, GOTO) were grown in F 10 medium. The cells were spread in 24-well plates, irradiated with different doses, cultured for about one week and stained with crystal violet after the culture period. Taking the transparent images of the stained well on the light source with the CCD camera, the images were collected with the matrix size 64 x 64, and the integrated optical density of the entire surface of each well was determined by computer with our original program. As the number of cells in the well is reflected by its staining density, the surviving fraction was calculated as the fraction of growth in the irradiated wells relative to controls. The survival curves obtained by the densitometry method showed good correlations with those obtained by clonogenic assay. It is possible to predict intrinsic radiosensitivity with this assay, even if the cells do not form good colonies. However, this method is based on measurements in cultures which depend on the metabolism and growth kinetics of the irradiated cells. Cells should grow exponetially in the same manner in any well to obtain a result similar to that of clonogenic assay, although growth kinetics may be altered by irradiation. This, the endpoint must be strictly standardized. (author)
International Nuclear Information System (INIS)
This study monitors some trace elements concentration in street and industrial dust from Wad Medani city, Gezira State in central Sudan. A total of 20 samples of dust were collected from crowded and non-crowded streets, material processing workshop and a tannery. Samples were treated by sequential chemical extraction in five fractions, which termed as exchangeable fraction, carbonate fraction, Fe-Mn oxides fraction, organic matter fraction and residual fraction. The same samples were digested by wet method. The obtained solutions were analyzed for Cr, Fe, Ni, Cu, Zn, and Pb content using Atomic Absorption Spectrometer (AAS) and for Na and K content using Flame Emission Spectrometer (FES). X-Ray Fluorescence Spectrometer (XRF) was used to determine the total content of Na, K, Cr, Fe, Ni, Cu, Zn and Pb in the bulk sample. Results of total content, which obtained by AAS, FES and XRF spectrometry, were compared with each other and with total content for the fractionated samples. Certified reference materials from IAEA were analyzed to make sure of the data obtained. The ranges of concentrations obtained are 113-3900 μg/g for Cr, 0.3-110.4 mg/g for Fe, 27-500 μg/g for Ni, 34.7-4390 μ/g for Cu, 62-1320 μg/g for Zn and 40-1250 μg/g for Pb dry weight. The obtained results were analyzed statistically using multivariate methods that include Correlation Matrices, Principal Component Analysis (PCA) and cluster analysis. The concentrations of trace elements in street and industrial dust of Wad Medani were compared with those values in literature. It has been observed that the dust from street and industrial area of wad Medani is slightly affected by anthropogenic sources.(Author)
Kaur, Navneet; Lacasse, Martine; Fürtös, Alexandra; Waldron, Karen C; Morin, André
2009-06-01
Chlorogenic acid is the most abundant polyphenol found in the tobacco plant. The biological effects of its combustion products remain largely unknown. In this study, chlorogenic acid was burned at 640 degrees C for 2 min and the particulate matter of the smoke was collected onto Cambridge filter pads followed by selective extraction in five different solvents. Various fractions of the chlorogenic acid combustion products were tested for induction of micronuclei in V79 Chinese hamster fibroblast cells. Over 40 compounds were identified in the dimethyl sulfoxide (DMSO) extract by high-performance liquid chromatography coupled to electrospray time-of-flight mass spectrometry (HPLC/TOF-MS). The DMSO extract was then fractionated into three major fractions by preparative LC. The fraction inducing the highest degree of toxicity was further separated into four sub-fractions. The sub-fraction responsible for the most toxic response was determined to contain catechol as its major component. The overall reproducibility of the combustion, the extraction procedure and the chemical characterization of the compounds responsible for the toxicity in the chlorogenic acid smoke were evaluated by LC/TOF-MS. PMID:19414175
Chemical fractionation of Cu and Zn in stormwater, roadway dust and stormwater pond sediments
Camponelli, Kimberly M.; Lev, Steven M.; Snodgrass, Joel W.; Landa, Edward R.; Casey, Ryan E.
2010-01-01
This study evaluated the chemical fractionation of Cu and Zn from source to deposition in a stormwater system. Cu and Zn concentrations and chemical fractionation were determined for roadway dust, roadway runoff and pond sediments. Stormwater Cu and Zn concentrations were used to generate cumulative frequency distributions to characterize potential exposure to pond-dwelling organisms. Dissolved stormwater Zn exceeded USEPA acute and chronic water quality criteria in approximately 20% of storm samples and 20% of the storm duration sampled. Dissolved Cu exceeded the previously published chronic criterion in 75% of storm samples and duration and exceeded the acute criterion in 45% of samples and duration. The majority of sediment Cu (92–98%) occurred in the most recalcitrant phase, suggesting low bioavailability; Zn was substantially more available (39–62% recalcitrant). Most sediment concentrations for Cu and Zn exceeded published threshold effect concentrations and Zn often exceeded probable effect concentrations in surface sediments.
The measurement of the chemically mobile fraction of lead in soil using isotopic dilution analysis
International Nuclear Information System (INIS)
The chemically available fraction of lead in eight soils measured by isotopic dilution analysis using 212Pb ranged from 7 to 16% of the total content of lead in soil. The soluble fractions achieved values up to 63% of the total content in 1 M NH4NO3, 1 M MgCl2 and 0.05 M DTPA solutions. Increasing the contact time between water and soil, the water-soil ratio from 1:1 to 5:1 and increasing the temperature of the soil-water suspension raised the chemically available fraction in soil. Comparing various soil parameters and the mobile fraction of lead, only pH shows a significant correlation. The amphoteric character of lead causes a minimum of mobility about pH 6; pH-values below are responsible for the higher mobility of lead as Pb2+, at pH-values above 6 soluble hydroxy and humic acid complexes are formed. (orig.)
International Nuclear Information System (INIS)
The arsenic (As) contaminated sediment serves as a long-term source of arsenic because its mobility and transport in the environment are strongly influenced to associated solid phase. A single extraction method based on the reagents employed in the BCR three steps sequential extraction scheme (BCR-SES) for partitioning of arsenic (As) in sediment samples has been developed. The single-step extraction enabled a reduction of extraction times, yielding extractable contents in accordance with those obtained by application of the BCR-SES, which can be regarded as a standard method and validated by using certified reference material BCR 701. The extractable As content associated with different phases in sediment samples were analysed by electrothermal atomic absorption spectrophotometer. The extraction efficiency of As by single-step extraction was slightly higher than BCR-SES, ranged (100-104%), while difference was not significant at 95% confidence limit with <10% precision. The sediment samples from different origins varied in their physico-chemical properties and total As content. The relative mobility of As obtained from different origins was found in increasing order as: acid soluble fraction < oxidizable fraction < reducible fraction. The acid soluble fraction of As was higher in lake sediment samples as compared to those of canal and river sediments, indicating the contamination of lake ecosystem.
Study on calculation methods for the effective delayed neutron fraction
International Nuclear Information System (INIS)
The effective delayed neutron fraction βeff is one of the important neutronic parameters from a view point of a reactor kinetics. Several Monte-Carlo-based methods to estimate βeff have been proposed to date. In order to quantify the accuracy of these methods, we study calculation methods for βeff by analyzing various fast neutron systems including the bare spherical systems (Godiva, Jezebel, Skidoo, Jezebel-240), the reflective spherical systems (Popsy, Topsy, Flattop-23), MASURCA-R2 and MASURCA-ZONA2, and FCA XIX-1, XIX-2 and XIX-3. These analyses are performed by using SLAROM-UF and CBG for the deterministic method and MVP-II for the Monte Carlo method. We calculate βeff with various definitions such as the fundamental value β0, the standard definition, Nauchi's definition and Meulekamp's definition, and compare these results with each other. Through the present study, we find the following: The largest difference among the standard definition of βeff , Nauchi's βeff and Meulekamp's βeff is approximately 10%. The fundamental value β0 is quite larger than the others in several cases. For all the cases, Meulekamp's βeff is always higher than Nauchi's βeff. This is because Nauchi's βeff considers the average neutron multiplicity value per fission which is large in the high energy range (1MeV-10MeV), while the definition of Meulekamp's βeff does not include this parameter. Furthermore, we evaluate the multi-generation effect on βeff values and demonstrate that this effect should be considered to obtain the standard definition values of βeff. (author)
Analytical method for space-fractional telegraph equation by homotopy perturbation transform method
Prakash, Amit
2016-06-01
The object of the present article is to study spacefractional telegraph equation by fractional Homotopy perturbation transform method (FHPTM). The homotopy perturbation transform method is an innovative adjustment in Laplace transform algorithm. Three test examples are presented to show the efficiency of the proposed technique.
Advanced methods in the fractional calculus of variations
Malinowska, Agnieszka B; Torres, Delfim F M
2015-01-01
This brief presents a general unifying perspective on the fractional calculus. It brings together results of several recent approaches in generalizing the least action principle and the Euler–Lagrange equations to include fractional derivatives. The dependence of Lagrangians on generalized fractional operators as well as on classical derivatives is considered along with still more general problems in which integer-order integrals are replaced by fractional integrals. General theorems are obtained for several types of variational problems for which recent results developed in the literature can be obtained as special cases. In particular, the authors offer necessary optimality conditions of Euler–Lagrange type for the fundamental and isoperimetric problems, transversality conditions, and Noether symmetry theorems. The existence of solutions is demonstrated under Tonelli type conditions. The results are used to prove the existence of eigenvalues and corresponding orthogonal eigenfunctions of fractional Stur...
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Neerja Puri
2013-01-01
Full Text Available Introduction: Melasma is a commonly acquired hypermelanosis and a common dermatologic skin disease that occurs on sun-exposed areas of face. Aims: To assess the efficacy and safety of non-ablative 1,550 nm Erbium glass fractional laser therapy and compare results with those obtained with chemical peeling. Materials and Methods: We selected 30 patients of melasma aged between 20 years and 50 years for the study. The patients were divided into two groups of 15 patients each. Group I patients were subjected to four sessions of 1,550 nm Erbium glass non-ablative fractional laser at 3 weeks interval. In group II patients, four sessions of chemical peeling with 70% glycolic acid was performed. Results: After 12 weeks of treatment, percentage reduction in Melasma Area and Severity Index (MASI score was seen in 62.9% in the laser group and 58.7% in the peels group. Conclusion: It was observed that 1,550 nm fractional laser is as effective as 70% glycolic acid peel in reducing MASI score in patients with melasma.
Neerja Puri
2013-01-01
Introduction: Melasma is a commonly acquired hypermelanosis and a common dermatologic skin disease that occurs on sun-exposed areas of face. Aims: To assess the efficacy and safety of non-ablative 1,550 nm Erbium glass fractional laser therapy and compare results with those obtained with chemical peeling. Materials and Methods: We selected 30 patients of melasma aged between 20 years and 50 years for the study. The patients were divided into two groups of 15 patients each. Group I patients we...
Energy Technology Data Exchange (ETDEWEB)
Carella, Alfredo Raul
2012-09-15
Quantifying species transport rates is a main concern in chemical and petrochemical industries. In particular, the design and operation of many large-scale industrial chemical processes is as much dependent on diffusion as it is on reaction rates. However, the existing diffusion models sometimes fail to predict experimentally observed behaviors and their accuracy is usually insufficient for process optimization purposes. Fractional diffusion models offer multiple possibilities for generalizing Flick's law in a consistent manner in order to account for history dependence and nonlocal effects. These models have not been extensively applied to the study of real systems, mainly due to their computational cost and mathematical complexity. A least squares spectral formulation was developed for solving fractional differential equations. The proposed method was proven particularly well-suited for dealing with the numerical difficulties inherent to fractional differential operators. The practical implementation was explained in detail in order to enhance reproducibility, and directions were specified for extending it to multiple dimensions and arbitrarily shaped domains. A numerical framework based on the least-squares spectral element method was developed for studying and comparing anomalous diffusion models in pellets. This simulation tool is capable of solving arbitrary integro-differential equations and can be effortlessly adapted to various problems in any number of dimensions. Simulations of the flow around a cylindrical particle were achieved by extending the functionality of the developed framework. A test case was analyzed by coupling the boundary condition yielded by the fluid model with two families of anomalous diffusion models: hyperbolic diffusion and fractional diffusion. Qualitative guidelines for determining the suitability of diffusion models can be formulated by complementing experimental data with the results obtained from this approach.(Author)
Tan, Jihua; Duan, Jingchun; Zhen, Naijia; He, Kebin; Hao, Jiming
2016-01-01
The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl-, NO3-, SO42 -, NH4+, Na+, K+, Ca2 +, and Mg2 +) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC + EC) was reconstructed. Averagely, 51.5 ± 5.3% and 74.1 ± 3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42 -, NO3-, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42 -, NO3-, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (fine, intermediate, and coarse modes; and (IV) those which were mainly found within particles larger than 2.7 μm (Al, Mg, Si, Ca, Sc, Tl, Fe, Sr, Zr, and Ba). [H+]cor showed an accumulation mode at 600-700 nm and the role of Ca2 + should be fully considered in the estimation of acidity. The acidity in accumulation mode particles suggested that generally gaseous NH3 was not enough to neutralize sulfate completely. PMF method was applied for source apportionment of elements combined with water soluble ions. Dust, vehicle, aged coal combustion, and sea salt were identified, and the size resolved source apportionments were discussed. Aged coal combustion was the important source of fine particles and dust contributed most to coarse particle.
Directory of Open Access Journals (Sweden)
Razam Ab Latip
2013-05-01
Full Text Available Fractionation which separates the olein (liquid and stearin (solid fractions of oil is used to modify the physicochemical properties of fats in order to extend its applications. Studies showed that the properties of fractionated end products can be affected by fractionation processing conditions. In the present study, dry fractionation of palm-based diacylglycerol (PDAG was performed at different: cooling rates (0.05, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0°C/min, end-crystallisation temperatures (30, 35, 40, 45 and 50°C and agitation speeds (30, 50, 70, 90 and 110 rpm to determine the effect of these parameters on the properties and yield of the solid and liquid portions. To determine the physicochemical properties of olein and stearin fraction: Iodine value (IV, fatty acid composition (FAC, acylglycerol composition, slip melting point (SMP, solid fat content (SFC, thermal behaviour tests were carried out. Fractionation of PDAG fat changes the chemical composition of liquid and solid fractions. In terms of FAC, the major fatty acid in olein and stearin fractions were oleic (C18:1 and palmitic (C16:0 respectively. Acylglycerol composition showed that olein and stearin fractions is concentrated with TAG and DAG respectively. Crystallization temperature, cooling rate and agitation speed does not affect the IV, SFC, melting and cooling properties of the stearin fraction. The stearin fraction was only affected by cooling rate which changes its SMP. On the other hand, olein fraction was affected by crystallization temperature and cooling rate but not agitation speed which caused changes in IV, SMP, SFC, melting and crystallization behavior. Increase in both the crystallization temperature and cooling rate caused a reduction of IV, increment of the SFC, SMP, melting and crystallization behaviour of olein fraction and vice versa. The fractionated stearin part melted above 65°C while the olein melted at 40°C. SMP in olein fraction also reduced to a range of
Significance of oil droplets in chemically enhanced water-accommodated fraction
Energy Technology Data Exchange (ETDEWEB)
Ramachandran, S. [Queen' s Univ., Kingston, ON (Canada). School of Environmental Studies; Hodson, P.V.; Lee, K. [Department of Fisheries and Oceans, Dartmouth, NS (Canada). Bedford Inst. of Oceanography
2003-07-01
This presentation described the controversial use of chemical dispersions to treat oil spills on water. Dispersants break up the spill in order to reduce shoreline impacts, but the dispersant drives the oil into the water column in the form of droplets, thereby temporarily increasing hydrocarbon concentrations and causing negative impacts on aquatic organisms. Exposure experiments have been conducted on rainbow trout exposed to Mesa and Scotian Light Crude Oil, with and without oil droplets. The studies showed that the levels of polycyclic aromatic hydrocarbons (PAH) was higher in the trout exposed to Corexit water-accommodated fractions, compared to water-accommodated fractions. The results suggest that dispersing crude oil sustains hydrocarbon concentrations in a larger volume of water than if it were not dispersed. The oil droplets increase the partitioning of PAH into the water solution. They adhere to the gills of the fish, thereby facilitating direct uptake.
Tsai, Pei-Hsuan; You, Chen-Feng; Huang, Kuo-Fang; Chung, Chuan-Hisung; Sun, You-Bin
2014-06-01
Lithium (Li) is a fluid-mobile element and δ7Li in secondary deposits represents an excellent proxy for silicate weathering and authigenic mineral formation. The soil samples from 1205 to 1295 cm in the Weinan profile, one of the best developed loess-paleosol sequences covering the last glacial-interglacial climatic cycle, were collected and chemically separated into detritus and carbonate fractions for subsequent analyses of Li, δ7Li, major and trace elements. Other desert specimens (i.e., Qaidam Desert, Tengger Desert, Badain Juran Desert and Taklimakan Desert) near the Chinese Loess Plateau (CLP) and various standard clays were analyzed for assisting provenance determination. The Li and δ7Li distributions in the detritus are rather homogeneous, 1.4-2.0 μg/g and +2.5‰ to +4.7‰, respectively, compared with the carbonate fraction. The detrital δ7Li varies systematically with magnetic susceptibility and grain size changes, reflecting significant Li isotopic variation associated with sources and mineralogy of detrital material. On the other hand, Li and δ7Li in carbonates show large changes, 781-963 ng/g and -4.1‰ to +10.2‰, respectively. These carbonate δ7Li correlated well with the estimated index of chemical weathering, as a result of Li mobilization and soil formation during chemical weathering.
An Exact Method for a Discrete Multiobjective Linear Fractional Optimization
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Mohamed El-Amine Chergui
2008-01-01
Full Text Available Integer linear fractional programming problem with multiple objective (MOILFP is an important field of research and has not received as much attention as did multiple objective linear fractional programming. In this work, we develop a branch and cut algorithm based on continuous fractional optimization, for generating the whole integer efficient solutions of the MOILFP problem. The basic idea of the computation phase of the algorithm is to optimize one of the fractional objective functions, then generate an integer feasible solution. Using the reduced gradients of the objective functions, an efficient cut is built and a part of the feasible domain not containing efficient solutions is truncated by adding this cut. A sample problem is solved using this algorithm, and the main practical advantages of the algorithm are indicated.
Chemical Methods for Ugnu Viscous Oils
Energy Technology Data Exchange (ETDEWEB)
Kishore Mohanty
2012-03-31
The North Slope of Alaska has large (about 20 billion barrels) deposits of viscous oil in Ugnu, West Sak and Shraeder Bluff reservoirs. These shallow reservoirs overlie existing productive reservoirs such as Kuparuk and Milne Point. The viscosity of the Ugnu reservoir on top of Milne Point varies from 200 cp to 10,000 cp and the depth is about 3300 ft. The same reservoir extends to the west on the top of the Kuparuk River Unit and onto the Beaufort Sea. The depth of the reservoir decreases and the viscosity increases towards the west. Currently, the operators are testing cold heavy oil production with sand (CHOPS) in Ugnu, but oil recovery is expected to be low (< 10%). Improved oil recovery techniques must be developed for these reservoirs. The proximity to the permafrost is an issue for thermal methods; thus nonthermal methods must be considered. The objective of this project is to develop chemical methods for the Ugnu reservoir on the top of Milne Point. An alkaline-surfactant-polymer (ASP) formulation was developed for a viscous oil (330 cp) where as an alkaline-surfactant formulation was developed for a heavy oil (10,000 cp). These formulations were tested in one-dimensional and quarter five-spot Ugnu sand packs. Micromodel studies were conducted to determine the mechanisms of high viscosity ratio displacements. Laboratory displacements were modeled and transport parameters (such as relative permeability) were determined that can be used in reservoir simulations. Ugnu oil is suitable for chemical flooding because it is biodegraded and contains some organic acids. The acids react with injected alkali to produce soap. This soap helps in lowering interfacial tension between water and oil which in turn helps in the formation of macro and micro emulsions. A lower amount of synthetic surfactant is needed because of the presence of organic acids in the oil. Tertiary ASP flooding is very effective for the 330 cp viscous oil in 1D sand pack. This chemical formulation
International Nuclear Information System (INIS)
Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: → Isotope ratios can be used to evaluate chemical methods to predict bioavailability. → Chemical methods predicted bioavailability better than exhaustive extractions. → Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.
Numerical comparison of methods for solving linear differential equations of fractional order
Energy Technology Data Exchange (ETDEWEB)
Momani, Shaher [Department of Mathematics, Mutah University, P.O. Box 7, Al-Karak (Jordan)]. E-mail: shahermm@yahoo.com; Odibat, Zaid [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa' Applied University, Salt (Jordan)]. E-mail: odibat@bau.edu.jo
2007-03-15
In this article, we implement relatively new analytical techniques, the variational iteration method and the Adomian decomposition method, for solving linear differential equations of fractional order. The two methods in applied mathematics can be used as alternative methods for obtaining analytic and approximate solutions for different types of fractional differential equations. In these schemes, the solution takes the form of a convergent series with easily computable components. This paper will present a numerical comparison between the two methods and a conventional method such as the fractional difference method for solving linear differential equations of fractional order. The numerical results demonstrates that the new methods are quite accurate and readily implemented.
Indian Academy of Sciences (India)
Wenjun Liu; Kewang Chen
2013-09-01
In this paper, we implemented the functional variable method and the modified Riemann–Liouville derivative for the exact solitary wave solutions and periodic wave solutions of the time-fractional Klein–Gordon equation, and the time-fractional Hirota–Satsuma coupled KdV system. This method is extremely simple but effective for handling nonlinear time-fractional differential equations.
International Nuclear Information System (INIS)
A sequential chemical extraction method for the determination of the geochemical fractionation of Am, Pu, and U was evaluated rigorously on a single marine sediment standard (IAEA-135). Partitioning of actinides was operationally defined for five reagent fractions and stable element analyses (Al, Ca, Fe, Mn, Ti, etc.) were performed to assist in establishing the phase specificity of the extractions. The method produces, in general, results that agree to within a one standard deviation interval for replicate measurements for each fraction. Actinide readsorption, examined by a double-spiking technique, was found to be significant in some cases. Ethylenediamine-tetraacetic acid (EDTA) was examined as a hold-back reagent to lessen the effect of readsorption but seriously compromised the phase selectivity of the extractants. In addition, the use of NaOCl for the destruction of organic matter was found to dissolve carbonates out of sequence and is not recommended for carbonate-bearing materials. (Copyright (c) 1988 Elsevier Science B.V., Amsterdam. All rights reserved.)
A method for detecting the presence of organic fraction in nucleation mode sized particles
Directory of Open Access Journals (Sweden)
P. Vaattovaara
2005-06-01
Full Text Available New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm and the lower end of Aitken mode particles (d≤50 nm is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer method to shed light on the presence of organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.
A method for detecting the presence of organic fraction in nucleation mode sized particles
Directory of Open Access Journals (Sweden)
P. Vaattovaara
2005-01-01
Full Text Available New particle formation and growth has a very important role in many climate processes. However, the overall knowlegde of the chemical composition of atmospheric nucleation mode (particle diameter, d<20 nm and the lower end of Aitken mode particles (d≤50 nm is still insufficient. In this work, we have applied the UFO-TDMA (ultrafine organic tandem differential mobility analyzer method to shed light on the presence of an organic fraction in the nucleation mode size class in different atmospheric environments. The basic principle of the organic fraction detection is based on our laboratory UFO-TDMA measurements with organic and inorganic compounds. Our laboratory measurements indicate that the usefulness of the UFO-TDMA in the field experiments would arise especially from the fact that atmospherically the most relevant inorganic compounds do not grow in subsaturated ethanol vapor, when particle size is 10 nm in diameter and saturation ratio is about 86% or below it. Furthermore, internally mixed particles composed of ammonium bisulfate and sulfuric acid with sulfuric acid mass fraction ≤33% show no growth at 85% saturation ratio. In contrast, 10 nm particles composed of various oxidized organic compounds of atmospheric relevance are able to grow in those conditions. These discoveries indicate that it is possible to detect the presence of organics in atmospheric nucleation mode sized particles using the UFO-TDMA method. In the future, the UFO-TDMA is expected to be an important aid to describe the composition of atmospheric newly-formed particles.
Occurrence of non extractable pesticide residues in physical and chemical fractions of two soils
Andreou, Kostas; Semple, Kirk; Jones, Kevin
2010-05-01
Soils are considered to be a significant sink for organic contaminants, including pesticides, in the environment. Understanding the distribution and localisation of aged pesticide residues in soil is of great importance for assessing the mobility and availability of these chemicals in the environment. This study aimed to characterise the distribution of radiolabeled herbicide isoproturon and the radiolabeled insecticides diazinon and cypermethrin in two organically managed soils. The soils were spiked and aged under laboratory conditions for 17 months. The labile fraction of the pesticides residues was recovered in CaCl2 (0.01M) and then subjected to physical size fractionation using sedimentation and centrifugation steps, with >20μm, 20-2μm and 2-0.1μm soil factions collected. Further, the distribution of the pesticide residues in the organic matter of the fractionated soil was investigated using a sequential alkaline extraction (0.1N NaOH) into humic and fulvic acid and humin. Soil fractions of 20-2μm and 2-0.1μm had the largest burden of the 14C-residues. Different soil constituents have different capacities to form non-extractable residues. Soil solid fractions of 20-2 µm and 20 µm). Fulvic acid showed to play a vital role in the formation and stabilisation of non-extractable 14C-pesticide residues in most cases.Assessment of the likelihood of the pesticide residues to become available to soil biota requires an understanding of the structure of the SOM matrix and the definition of the kinetics of the pesticide residues in different SOM pools as a function of the time.
Exponential rational function method for space-time fractional differential equations
Aksoy, Esin; Kaplan, Melike; Bekir, Ahmet
2016-04-01
In this paper, exponential rational function method is applied to obtain analytical solutions of the space-time fractional Fokas equation, the space-time fractional Zakharov Kuznetsov Benjamin Bona Mahony, and the space-time fractional coupled Burgers' equations. As a result, some exact solutions for them are successfully established. These solutions are constructed in fractional complex transform to convert fractional differential equations into ordinary differential equations. The fractional derivatives are described in Jumarie's modified Riemann-Liouville sense. The exact solutions obtained by the proposed method indicate that the approach is easy to implement and effective.
Spectroscopic chemical analysis methods and apparatus
Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor)
2013-01-01
Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.
Chemical Analysis of Fractionated Halogens in Atmospheric Aerosols Collected in Okinawa, Japan
Tsuhako, A.; Miyagi, Y.; Somada, Y.; Azechi, S.; Handa, D.; Oshiro, Y.; Murayama, H.; Arakaki, T.
2013-12-01
Halogens (Cl, Br and I) play important roles in the atmosphere, e.g. ozone depletion by Br during spring in Polar Regions. Sources of halogens in atmospheric aerosols are mainly from ocean. But, for example, when we analyzed Br- with ion chromatography, its concentrations were almost always below the detection limit, which is also much lower than the estimated concentrations from sodium ion concentrations. We hypothesized that portions of halogens are escaped to the atmosphere, similar to chlorine loss, changed their chemical forms to such as BrO3- and IO3-, and/or even formed precipitates. There was few reported data so far about fractionated halogen concentrations in atmospheric aerosols. Thus, purpose of this study was to determine halogen concentrations in different fractions; free ion, water-soluble chemically transformed ions and precipitates using the authentic aerosols. Moreover, we analyzed seasonal variation for each fraction. Atmospheric aerosol samples were collected at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS) of Okinawa, Japan during January 2010 and August 2013. A high volume air sampler was used for collecting total particulate matters on quartz filters on a weekly basis. Ultrapure water was used to extract water-soluble factions of halogens. The extracted solutions were filtered with the membrane filter and used for chemical analysis with ion chromatography and ICP-MS. Moreover, the total halogens in aerosols were obtained after digesting aerosols with tetramethylammonium hydroxide (TMAH) using the microwave and analysis with ICP-MS. For Cl, water-soluble Cl- accounted for about 70% of the estimates with Na content. No other forms of water-soluble Cl were found. About 30% of Cl was assumed volatilized to the gas-phase. For Br, water-soluble Br accounted for about 43% of the estimates with Na content, and within the 43%, about 10% of Br was not in the form of Br-. About 46% of Br was assumed volatilized to the gas-phase. For I
Standard test method for measurement of 235U fraction using enrichment meter principle
American Society for Testing and Materials. Philadelphia
2008-01-01
1.1 This test method covers the quantitative determination of the fraction of 235U in uranium using measurement of the 185.7 keV gamma-ray produced during the decay of 235U. 1.2 This test method is applicable to items containing homogeneous uranium-bearing materials of known chemical composition in which the compound is considered infinitely thick with respect to 185.7 keV gamma-rays. 1.3 This test method can be used for the entire range of 235U fraction as a weight percent, from depleted (0.2 % 235U) to highly enriched (97.5 % 235U). 1.4 Measurement of items that have not reached secular equilibrium between 238U and 234Th may not produce the stated bias when low-resolution detectors are used with the computational method listed in Annex A2. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety co...
On an Estimation Method for an Alternative Fractionally Cointegrated Model
DEFF Research Database (Denmark)
Carlini, Federico; Łasak, Katarzyna
In this paper we consider the Fractional Vector Error Correction model proposed in Avarucci (2007), which is characterized by a richer lag structure than models proposed in Granger (1986) and Johansen (2008, 2009). We discuss the identification issues of the model of Avarucci (2007), following th...
Phytotoxic activity and chemical composition of aqueous volatile fractions from Eucalyptus species.
Directory of Open Access Journals (Sweden)
Jinbiao Zhang
Full Text Available The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.. The aqueous volatile fractions (AVFs were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph-mass spectrometry (GC-MS. Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species.
Physico-chemical characteristics and nutraceutical distribution of crude palm oil and its fractions
Directory of Open Access Journals (Sweden)
Prasanth Kumar, P. K.
2014-06-01
Full Text Available Crude palm oil (CRPO was dry fractionated at 25 °C to get crude palm olein (CRPOL, 77% and crude palm stearin (CRPS, 23%. Low and high melting crude palm stearin (LMCRPS 14.3% and HMCRPS 8.7% were separated by further fractionation of CRPS with acetone. The physico-chemical parameters and nutraceutical distribution showed variation in different fractions. The CRPO contained 514.7 mg·Kg−1 of β-carotene and 82.6%, 16.1%, 12.5% and 3.1% of it was distributed in CRPOL, CRPS, LMCRPS and HMCRPS respectively. The distribution of phytosterols in fraction was 1870.2, 1996.8, 1190.9, 1290.4 and 115.4 mg·Kg−1 for CRPO, CRPOL, CRPS, LMCRPS and HMCRPS respectively. Total tocopherol composition was 535.5, 587.1, 308.0, 305.6 and 36.2 mg·Kg−1 for CRPO, CRPOL, CRPS, LMCRPS and HMCRPS respectively. The results show that the fractionation of CRPO may be helpful in the preparation of nutraceutical-rich fractions.Aceite de palma crudo (CRPO fue fraccionado en seco a 25 °C para obtener oleína de palma cruda (CRPOL, 77% y estearinas de palma cruda (CRPS, el 23%. Estearinas con bajo y alto punto de fusión (LMCRPS 14,3% y HMCRPS 8,7% se separan por fraccionamiento adicional de CRPS con acetona. Los parámetros físico- químicos y la distribución de nutracéuticos muestra diferencias entre las fracciones. El CRPO contenía 514,7 mg·Kg−1 de β-caroteno y el 82,6%, 16,1%, 12,5% y 3,1% de este se distribuye en CRPOL, CRPS, LMCRPS y HMCRPS respectivamente. Los fitosteroles en las fracciones fue de: 1870,2, 1996,8, 1190.9, 1290,4 y 115,4 mg·Kg−1 para CRPO, CRPOL, CRPS, LMCRPS y HMCRPS respectivamente. La composición total de tocoferol fue 535,5, 587,1 308,0, 305,6 y 36,2 mg·Kg−1, para CRPO, CRPOL, CRPS, LMCRPS y HMCRPS respectivamente. Los resultados mostraron que el fraccionamiento de CRPO puede ser útil en la preparación de fracciones ricas en nutracéuticos.
Analysis of the Two-Fraction Method for Generating Primitive Pythagoras Triples
Babajee, Diyashvir Kreetee Rajiv
2012-01-01
Finding methods for generating Pythagorean triples have been of great interest to Mathematicians since the Babylonians (from 1900 to 1600 BC). One of these methods is the less known two-fraction method which works for any two fractions whose product is 2. In this work, we analyse the method and show that it can be obtained from the fact that the…
On the multimodality of preparative TREF fractionation as detected by advanced analytical methods.
Ndiripo, Anthony; Pasch, Harald
2015-08-01
Preparative temperature rising elution fractionation (prepTREF) is the standard technique for the preparative fractionation of polyolefins according to crystallisability. For olefin copolymers such as linear low-density polyethylene (LLDPE), it was believed that the TREF elution temperature correlates directly with the copolymer composition. For copolymers having different bulk comonomer contents, the prepTREF fractions of different samples collected at a given temperature were assumed to have the same chemical composition. It was acknowledged quite early that co-crystallisation effects may disturb TREF fractionation and fractions are obtained that are not completely homogeneous. This, however, has not been investigated quantitatively so far. The fundamental statement of prepTREF is challenged for the first time quantitatively using advanced analytical techniques including high-temperature high-performance liquid chromatography (HPLC). Ethylene-1-octene copolymers having bulk comonomer contents ranging from 0.3 to 6.4 mol% were fractionated by prepTREF, and the fractions were analysed by high-temperature size exclusion chromatography, crystallisation analysis fractionation, differential scanning calorimetry and high-temperature HPLC. All analytical results prove that the TREF fractions collected from different samples at the same elution temperature have different chemical compositions. The chemical compositions of the fractions correlate with the compositions of the bulk samples in that the comonomer contents of similar TREF fractions increase with an increase of the comonomer content of the bulk samples. These results are in clear contrast to the previous assumption that the TREF fraction composition is independent of the bulk copolymer composition for a given copolymer type. Graphical abstract Advanced analysis of LLDPE by combination of HT-HPLC, DSC and CRYSTAF. PMID:26055883
International Nuclear Information System (INIS)
Neutron diffraction data collected from ferrosilicon alloy powders have been analysed using the Rietveld profile-refinement method in order to perform a quantitative determination of the phase volume fraction. The results obtained have been compared with those determined from other methods such as imaging analysis, chemical analysis and phase-diagram calculation by a thermodynamic approach. For low phase volume fractions, the Rietveld profile refinement of the neutron-powder-diffractometer data gives results that are more accurate than those from imaging analysis and that are more representative at the ingot scale than those from chemical analysis, owing to the greater quantity of powder analysed. As concerns the thermodynamic calculations, two phase volume fraction determinations may be performed: quantitative, at equilibrium, and qualitative, out of equilibrium. (orig.)
Directory of Open Access Journals (Sweden)
Yan Li-Mei
2013-01-01
Full Text Available The purpose of this paper is to extend the homotopy perturbation method to fractional heat transfer and porous media equations with the help of the Laplace transform. The fractional derivatives described in this paper are in the Caputo sense. The algorithm is demonstrated to be direct and straightforward, and can be used for many other non-linear fractional differential equations.
Modified AOAC three step method (officialmethod 2008.05): consolidation of fractions B and C.
Rastogi, Vipin K; Smith, Lisa S; Wallace, Lalena; Tomasino, Stephen F
2013-01-01
The AOAC Quantitative Three Step Method (TSM; AOAC Official Method SM 2008.05) is validated for testing the efficacy of liquid sporicides against spores of Bacillus subtilis and Bacillus anthracis on selected hard, nonporous, and porous surfaces. The TSM uses 5x5x1 mm inoculated coupons (carriers), which are placed in 400 microL liquid sporicidal agent contained in a microcentrifuge tube. Following exposure of inoculated carriers to the test chemical and subsequent neutralization, viable spores are recovered in three fractions: A (gentle tapping), B (sonication), and C (gentle agitation). The spores in suspension are serially diluted and plated on a recovery medium for enumeration. The plate counts are summed over the three fractions to provide the number of viable spores per carrier, which is log10-transformed to generate a mean log density (LD) value across carriers. As a measure of product efficacy, a log reduction (LR) value is calculated by subtracting the mean LD for treated carriers from the mean LD for control carriers. This paper reports on the comparative evaluation of the current and modified versions of the TSM in order to support a modification to simplify the procedure. The proposed modified TSM (mTSM) consolidates fractions B and C in the same tube. Thus, the sonication (fraction B) and gentle agitation (fraction C) steps are carried out in the same tube, thereby reducing the number of tubes and associated resources and time necessary to complete the test. Glass, steel, pine wood, and ceramic tile carriers were included in the comparative study. Inoculated carriers were evaluated against two preparations of sodium hypochlorite to generate two presumed levels of efficacy (intermediate and high); the control LD and LR values associated with testing each carrier type for the TSM and the mTSM were compared. For control carriers, the mean log densities per carrier (for each carrier material) were not significantly different based on the TSM compared to
Analysis of fractional Gaussian noises using level crossing method
International Nuclear Information System (INIS)
The so-called level crossing analysis has been used to investigate the empirical data set, but there is a lack of interpretation for what is reflected by the level crossing results. The fractional Gaussian noise as a well-defined stochastic series could be a suitable benchmark to make more sense of the level crossing findings. In this paper, we calculated the average frequency of upcrossing for a wide range of fractional Gaussian noises from logarithmic (zero Hurst exponent, H = 0), to Gaussian, H = 1 (0 < H < 1). By introducing the relative change of the total number of upcrossings for original data with respect to the so-called shuffled data, R, an empirical function for the Hurst exponent versus R has been established. Finally to make the concept more obvious, we applied this approach to some financial series
International Nuclear Information System (INIS)
In the sequential fractionation of phosphorus, a modified approach in the oxidation process of the occluded fraction of phosphorus (in iron oxides in soils) using redox titration in nitric medium is presented. Also a new spectrophotometric method to determine that phosphorus fraction as the phosphomolybdate complex using a mixture of isobutyl acetate and methyl isobutyl ketone to extract the formed complex into the organic phase. Radioactive tracers (32P) and sequential extraction are used to state the yield of extraction of the phosphomolybdate complex. Accuracy, precision, detection limit, and the linearity of the present method are 1.04%, 0.0322μg ml-1 respectively. The results correlate significantly with the results of the standard method of Petersen and Corey (1996), and the procedure saves time (50 min) and chemicals. (author)
Solution of the Fractional Black-Scholes Option Pricing Model by Finite Difference Method
Lina Song; Weiguo Wang
2013-01-01
This work deals with the put option pricing problems based on the time-fractional Black-Scholes equation, where the fractional derivative is a so-called modified Riemann-Liouville fractional derivative. With the aid of symbolic calculation software, European and American put option pricing models that combine the time-fractional Black-Scholes equation with the conditions satisfied by the standard put options are numerically solved using the implicit scheme of the finite difference method.
A. H. Baghaie; A. H. Khoshgoftarmanesh; M. Afyuni
2012-01-01
Cow manure and sewage sludge add heavy metals to soil. Organic and inorganic fractions in these compounds can immobilize heavy metals such as lead (Pb) and affect their bio-availability. This investigation was conducted to compare the effects of organic and inorganic fractions of sewage sludge and cow manure on distribution of lead chemical forms in soil as a completely randomized design. Treatments consisted of application of 10% (w/w) enriched sewage sludge and cow manure (6 g Pb kg-1 organ...
Mechanical method for separating fractions of incinerated urban refuse or similar industrial refuse
Energy Technology Data Exchange (ETDEWEB)
Benedetto, A.; Cuvillier, R.O.; Gony, J.N.
1977-08-30
A method is disclosed for separating fractions of incinerated refuse with a high recuperation yield without requiring special equipment. A first portion of the separation process may be applied to either an initially dry or an initially wet refuse. The refuse is at first screened to a median size. The oversized fraction is crushed and shredded and the non-magnetic fraction separated therefrom is sent commonly to a grinding-rolling mill which also receives the undersize fraction. The undersize fraction downstream of the grinding mill is further treated by a wet separating process, the method achieving separation of ferrous and nonferrous metals, of glasses and silicates, and of magnetic slags.
Feng, Qing-Hua
2013-05-01
In this paper, an extended Riccati sub-ODE method is proposed to establish new exact solutions for fractional differential-difference equations in the sense of modified Riemann—Liouville derivative. By a fractional complex transformation, a given fractional differential-difference equation can be turned into another differential-difference equation of integer order. The validity of the method is illustrated by applying it to solve the fractional Hybrid lattice equation and the fractional relativistic Toda lattice system. As a result, some new exact solutions including hyperbolic function solutions, trigonometric function solutions and rational solutions are established.
International Nuclear Information System (INIS)
In this paper, an extended Riccati sub-ODE method is proposed to establish new exact solutions for fractional differential-difference equations in the sense of modified Riemann—Liouville derivative. By a fractional complex transformation, a given fractional differential-difference equation can be turned into another differential-difference equation of integer order. The validity of the method is illustrated by applying it to solve the fractional Hybrid lattice equation and the fractional relativistic Toda lattice system. As a result, some new exact solutions including hyperbolic function solutions, trigonometric function solutions and rational solutions are established. (general)
Abedini, Mohammad; Nojoumian, Mohammad Ali; Salarieh, Hassan; Meghdari, Ali
2015-08-01
In this paper, model reference control of a fractional order system has been discussed. In order to control the fractional order plant, discrete-time approximation methods have been applied. Plant and reference model are discretized by Grünwald-Letnikov definition of the fractional order derivative using "Short Memory Principle". Unknown parameters of the fractional order system are appeared in the discrete time approximate model as combinations of parameters of the main system. The discrete time MRAC via RLS identification is modified to estimate the parameters and control the fractional order plant. Numerical results show the effectiveness of the proposed method of model reference adaptive control.
Institute of Scientific and Technical Information of China (English)
FENG Qing-Hua
2013-01-01
In this paper,an extended Riccati sub-ODE method is proposed to establish new exact solutions for fractional differential-difference equations in the sense of modified Riemann-Liouville derivative.By a fractional complex transformation,a given fractional differential-difference equation can be turned into another differential-difference equation of integer order.The validity of the method is illustrated by applying it to solve the fractional Hybrid lattice equation and the fractional relativistic Toda lattice system.As a result,some new exact solutions including hyperbolic function solutions,trigonometric function solutions and rational solutions are established.
Various methods for solving time fractional KdV-Zakharov-Kuznetsov equation
Guner, Ozkan; Aksoy, Esin; Bekir, Ahmet; Cevikel, Adem C.
2016-06-01
This paper presents the exact analytical solution of the (3+1)-dimensional time fractional KdV-Zakharov-Kuznetsov (KdV-ZK) equation with the help of the Kudryashov method, the exp-function method and the functional variable method. The fractional derivatives are described in Jumarie's sense.
New evidence for chemical fractionation of radioactive xenon precursors in fission chains
Meshik, A. P.; Pravdivtseva, O. V.; Hohenberg, C. M.
2016-04-01
Mass-spectrometric analyses of Xe released from acid-treated U ore reveal that apparent Xe fission yields significantly deviate from the normal values. The anomalous Xe structure is attributed to chemically fractionated fission (CFF), previously observed only in materials experienced neutron bursts. The least retentive CFF-Xe isotopes, 136Xe and 134Xe, typically escape in 2:1 proportion. Xe retained in the sample is complimentarily depleted in these isotopes. This nucleochemical process allows understanding of unexplained Xe isotopic structures in several geophysical environments, which include well gasses, ancient anorthosite, some mantle rocks, as well as terrestrial atmosphere. CFF is likely responsible for the isotopic difference in Xe in the Earth's and Martian atmospheres and it is capable of explaining the relationship between two major solar system Xe carriers: the Sun and phase-Q, found in meteorites.
Impact of aging on the solid phase chemical fractionation of uranium in soil
International Nuclear Information System (INIS)
A distinction should be made between persistence of total uranium (U) in soil and persistence of its bioavailable forms. As U age in soil, there is a change in bioavailability. The aging process is partially reversible if environmental parameters change, although a portion of the U ion will be securely entrapped in the soil particle lattice and not available to be re-solubilized. A study was carried out to reveals the impact of aging on chemical fractionation of U in amended soils from three different origin (Soil A: Metamorphic; Soil B: Sedimentary and Soil C: Ingenious basalt). For the study, 5g from each soil were amended with the 50 ml of water containing 100.0 mg/L of U in a falcon tube. After 7 days the supernatant was removed by centrifugation and the soil was allowed to air dry at room temperature
Tan, Jihua; Duan, Jingchun; Zhen, Naijia; He, Kebin; Hao, Jiming
2016-01-01
The abundance, behavior, and source of chemical species in size-fractionated atmospheric particle were studied with a 13-stage low pressure impactor (ELPI) during high polluted winter episode in Beijing. Thirty three elements (Al, Ca, Fe, K, Mg, Na, Si, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Sr, Zr, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, Hg, Tl, and Pb) and eight water soluble ions (Cl-, NO3-, SO42 -, NH4+, Na+, K+, Ca2 +, and Mg2 +) were determined by ICP/MS and IC, respectively. The size distribution of TC (OC + EC) was reconstructed. Averagely, 51.5 ± 5.3% and 74.1 ± 3.7% of the total aerosol mass was distributed in the sub-micron (PM1) and fine particle (PM2.5), respectively. A significant shift to larger fractions during heavy pollution episode was observed for aerosol mass, NH4+, SO42 -, NO3-, K, Fe, Cu, Zn, Cd, and Pb. The mass size distributions of NH4+, SO42 -, NO3-, and K were dominated by accumulation mode. Size distributions of elements were classified into four main types: (I) elements were enriched within the accumulation mode (water soluble ions. Dust, vehicle, aged coal combustion, and sea salt were identified, and the size resolved source apportionments were discussed. Aged coal combustion was the important source of fine particles and dust contributed most to coarse particle.
Directory of Open Access Journals (Sweden)
Laura Núñez-Pons
2014-04-01
Full Text Available Generalist predation constitutes a driving force for the evolution of chemical defences. In the Antarctic benthos, asteroids and omnivore amphipods are keystone opportunistic predators. Sessile organisms are therefore expected to develop defensive mechanisms mainly against such consumers. However, the different habits characterizing each predator may promote variable responses in prey. Feeding-deterrence experiments were performed with the circumpolar asteroid macropredator Odontaster validus to evaluate the presence of defences within the apolar lipophilic fraction of Antarctic invertebrates and macroalgae. A total of 51% of the extracts were repellent, yielding a proportion of 17 defended species out of the 31 assessed. These results are compared with a previous study in which the same fractions were offered to the abundant circum-Antarctic amphipod Cheirimedon femoratus. Overall, less deterrence was reported towards asteroids (51% than against amphipods (80.8%, principally in sponge and algal extracts. Generalist amphipods, which establish casual host–prey sedentary associations with biosubstrata (preferentially sponges and macroalgae, may exert more localized predation pressure than sea stars on certain sessile prey, which would partly explain these results. The nutritional quality of prey may interact with feeding deterrents, whose production is presumed to be metabolically expensive. Although optimal defence theory posits that chemical defences are managed and distributed as to guarantee protection at the lowest cost, we found that only a few organisms localized feeding deterrents towards most exposed and/or valuable body regions. Lipophilic defensive metabolites are broadly produced in Antarctic communities to deter opportunistic predators, although several species combine different defensive traits.
Chemically reducing decontamination method for radioactive metal
International Nuclear Information System (INIS)
The present invention concerns a decontamination method of electrolytically reducing radioactive metal wastes, then chemically dissolving the surface thereof with a strong acid decontaminating solution. This method utilizes dissolving characteristics of stainless steels in the strong acid solution. That is, in the electrolytic reduction operation, a portion of the metal wastes is brought into contact with a strong acid decontaminating solution, and voltage and current are applied to the portion and keep it for a long period of time so as to make the potential of the immersed portion of the metal wastes to an active soluble region. Then, the electrolytic reduction operation is stopped, and the metal wastes are entirely immersed in the decontaminating solution to decontaminate by chemical dissolution. As the decontaminating solution, strong acid such as sulfuric acid, nitric acid is used. Since DC current power source capacity required for causing reaction in the active soluble region can be decreased, the decontamination facility can be minimized and simplified, and necessary electric power can be saved even upon decontamination of radioactive metal wastes made of stainless steels and having a great area. Further, chemical dissolution can be conducted without adding an expensive oxidizing agent. (N.H.)
Avila Ruiz, Geraldine; Arts, Anke; Minor, Marcel; Schutyser, Maarten
2016-01-01
Combination of dry and aqueous fractionation is investigated to obtain protein-rich fractions from quinoa in a milder and more sustainable way compared to conventional wet fractionation. Dry fractionation of quinoa involved milling and subsequent air classification, generating a protein-enriched embryo fraction. Subsequently, this fraction was milled, suspended, and further fractionated by aqueous phase separation. The efficiency of aqueous phase separation could be improved by addition of Na...
The Intelligence of Dual Simplex Method to Solve Linear Fractional Fuzzy Transportation Problem
2015-01-01
An approach is presented to solve a fuzzy transportation problem with linear fractional fuzzy objective function. In this proposed approach the fractional fuzzy transportation problem is decomposed into two linear fuzzy transportation problems. The optimal solution of the two linear fuzzy transportations is solved by dual simplex method and the optimal solution of the fractional fuzzy transportation problem is obtained. The proposed method is explained in detail with an example.
Hsu, Liang-Ching; Liu, Yu-Ting; Tzou, Yu-Min
2015-10-15
Sequential extraction has been widely used to classify metal species in soils and sediments; however, the lack of selectivity in extraction reagents may lead to the misinterpretation of metal speciation. In this study, we used X-ray absorption near edge structure (XANES) spectroscopy to classify Cr species based on its molecular form. These results complement the conventional Cr fractionation derived from the Tessier extraction method. The linear combination fitting (LCF) for the Cr-XANES spectra indicated that the Cr species in the soils could generally be described as Cr(III) sorbed on ferrihydrite (Cr-FH), Cr(III) complexed with humic acid (Cr-HA), and precipitated Cr. While the sum of the adsorbed Cr(III) and Cr(III)/Fe coprecipitates showed a nearly 1:1 relationship with reducible Cr, the total of Cr precipitates and organic Cr also followed the same trend with oxidizable Cr. This result indicated that there might be a underestimation in the reducible fraction as pure Cr(III) precipitates associated with surfaces of Fe minerals would not be extracted in the reducible process. Instead, such pure Cr(III) precipitates were dissolved during the oxidizable process, resulting in a overestimation in the fractionation of organic-related Cr. PMID:25935296
Relationship between redox activity and chemical speciation of size-fractionated particulate matter
Directory of Open Access Journals (Sweden)
Cho Arthur K
2007-06-01
Full Text Available Abstract Background Although the mechanisms of airborne particulate matter (PM related health effects remain incompletely understood, one emerging hypothesis is that these adverse effects derive from oxidative stress, initiated by the formation of reactive oxygen species (ROS within affected cells. Typically, ROS are formed in cells through the reduction of oxygen by biological reducing agents, with the catalytic assistance of electron transfer enzymes and redox active chemical species such as redox active organic chemicals and metals. The purpose of this study was to relate the electron transfer ability, or redox activity, of the PM samples to their content in polycyclic aromatic hydrocarbons and various inorganic species. The redox activity of the samples has been shown to correlate with the induction of the stress protein, hemeoxygenase-1. Results Size-fractionated (i.e. Conclusion The results of this work demonstrate the utility of the dithiothreitol assay for quantitatively assessing the redox potential of airborne particulate matter from a wide range of sources. Studies to characterize the redox activity of PM from various sources throughout the Los Angeles basin are currently underway.
Methods and Algorithms for Solving Inverse Problems for Fractional Advection-Dispersion Equations
Aldoghaither, Abeer
2015-11-12
Fractional calculus has been introduced as an e cient tool for modeling physical phenomena, thanks to its memory and hereditary properties. For example, fractional models have been successfully used to describe anomalous di↵usion processes such as contaminant transport in soil, oil flow in porous media, and groundwater flow. These models capture important features of particle transport such as particles with velocity variations and long-rest periods. Mathematical modeling of physical phenomena requires the identification of pa- rameters and variables from available measurements. This is referred to as an inverse problem. In this work, we are interested in studying theoretically and numerically inverse problems for space Fractional Advection-Dispersion Equation (FADE), which is used to model solute transport in porous media. Identifying parameters for such an equa- tion is important to understand how chemical or biological contaminants are trans- ported throughout surface aquifer systems. For instance, an estimate of the di↵eren- tiation order in groundwater contaminant transport model can provide information about soil properties, such as the heterogeneity of the medium. Our main contribution is to propose a novel e cient algorithm based on modulat-ing functions to estimate the coe cients and the di↵erentiation order for space FADE, which can be extended to general fractional Partial Di↵erential Equation (PDE). We also show how the method can be applied to the source inverse problem. This work is divided into two parts: In part I, the proposed method is described and studied through an extensive numerical analysis. The local convergence of the proposed two-stage algorithm is proven for 1D space FADE. The properties of this method are studied along with its limitations. Then, the algorithm is generalized to the 2D FADE. In part II, we analyze direct and inverse source problems for a space FADE. The problem consists of recovering the source term using final
Chemical techniques to extract organic fractions from fossil bones for accurate 14C dating
International Nuclear Information System (INIS)
We examined different concentrations of HCl, such as 0.4, 0.6, 0.8, 1.0 and 1.2 M, for decalcification of fossil bones and different times of 0.1 M NaOH treatment on collagens to determine the best conditions for purifying collagen through extraction of humic contaminants, and compared the alkali treatment method with the XAD-2 treatment method for several types of fossils. The yield of acid-insoluble bone fractions did not change over the range from 0.4 to 1.0 M HCl and decreased suddenly with 1.2 M HCl on decalcification, and the 14C ages of the extracted gelatins from the five decalcified fractions were unchanged, suggesting that 14C ages as those of the XAD-purified hydrolysates. The NaOH-treatment time should be less than several hours to avoid a loss of collagen. The fossil bones used are relatively well-preserved, but the alkali treatment could bring about a lot of loss of organic bone proteins for poorly-preserved bones. The XAD-2 treatment method is effective for accurate radiocarbon dating of fossil bones, if the XAD-2 resin is completely pre-cleaned
Chemical decontamination method for radioactive metal waste
International Nuclear Information System (INIS)
The present invention provides a chemical decontamination method for radioactive metal wastes, which are generated from radioactive material handling facilities and the surfaces of which are contaminated by radioactive materials. That is, it has a feature of applying acid dissolution simultaneously with mechanical grinding. The radioactive metal wastes are contained in a vessel such as a barrel together with abrasives in a sulfuric acid solution and rotated at several tens rotation per minute. By such procedures for the radioactive metal wastes, (1) cruds and passive membranes are mechanically removed, (2) exposed mother metal materials are uniformly brought into contact with sulfuric acid and further (3) the mother metal materials dissolve the cruds and the passive membranes also chemically by a reducing dissolution (so-called local cell effect). According to the method of the present invention, stainless steel metal wastes having cruds and passive membranes can rapidly and efficiently be decontaminated to a radiation level equal with that of ordinary wastes. (I.S.)
Götze, R; Pivnenko, K; Boldrin, A; Scheutz, C; Astrup, T Fruergaard
2016-08-01
Physico-chemical waste composition data are paramount for the assessment and planning of waste management systems. However, the applicability of data is limited by the regional, temporal and technical scope of waste characterisation studies. As Danish and European legislation aims for higher recycling rates evaluation of source-segregation and recycling chains gain importance. This paper provides a consistent up-to-date dataset for 74 physico-chemical parameters in 49 material fractions from residual and 24 material fractions from source-segregated Danish household waste. Significant differences in the physico-chemical properties of residual and source-segregated waste fractions were found for many parameters related to organic matter, but also for elements of environmental concern. Considerable differences in potentially toxic metal concentrations between the individual recyclable fractions within one material type were observed. This indicates that careful planning and performance evaluation of recycling schemes are important to ensure a high quality of collected recyclables. Rare earth elements (REE) were quantified in all waste fractions analysed, with the highest concentrations of REE found in fractions with high content of mineral raw materials, soil materials and dust. The observed REE concentrations represent the background concentration level in non-hazardous waste materials that may serve as a reference point for future investigations related to hazardous waste management. The detailed dataset provided here can be used for assessments of waste management solutions in Denmark and for the evaluation of the quality of recyclable materials in waste. PMID:27216729
Comment on “Variational Iteration Method for Fractional Calculus Using He’s Polynomials”
Directory of Open Access Journals (Sweden)
Ji-Huan He
2012-01-01
boundary value problems. This note concludes that the method is a modified variational iteration method using He’s polynomials. A standard variational iteration algorithm for fractional differential equations is suggested.
International Nuclear Information System (INIS)
A study of some artificial radionuclides discharged by the Krasnoyarsk Mining and Chemical Combine (KMCC) in different granulometric and organic fractions of alluvial soils was performed in the near and remote impact zones of the enterprise. Radionuclides were shown to concentrate in fine fractions enriched in hydro-mica and smectites. However in natural conditions the dominating size fraction associated with radionuclide accumulation at the study sites appeared to be made up of silt (0.010 mm) to clay (0.001 mm) sizes. Therefore due to radionuclide sorption and natural aggregation the peaks of a relatively high radionuclide mass accumulation were associated with three granulometric fractions: 60Co known for organic complexation were present in considerable relative amounts in the fraction of the most mobile low-molecular fulvic acids. (authors)
Energy Technology Data Exchange (ETDEWEB)
Korobova, Elena M.; Linnik, Vitaly G. [Vernadsky Institute of Geochemistry and Analytical Chemistry, 117991, Moscow (Russian Federation); Brown, Justin E. [Norwegian Radiation Protection Authority P.O. Box 55, N-1332 Oesteraas (Norway)
2014-07-01
A study of some artificial radionuclides discharged by the Krasnoyarsk Mining and Chemical Combine (KMCC) in different granulometric and organic fractions of alluvial soils was performed in the near and remote impact zones of the enterprise. Radionuclides were shown to concentrate in fine fractions enriched in hydro-mica and smectites. However in natural conditions the dominating size fraction associated with radionuclide accumulation at the study sites appeared to be made up of silt (0.010 mm) to clay (0.001 mm) sizes. Therefore due to radionuclide sorption and natural aggregation the peaks of a relatively high radionuclide mass accumulation were associated with three granulometric fractions: <0.001 mm, 0.063-0.010 mm and 0.25-0.125 mm. Soil granulometry was shown to reflect specificity of sedimentation at different landscape positions downstream from the KMCC. At the Balchug site a coarser fraction was accumulated close to the channel while finer fractions are deposited at a higher level. The portion of the clay fraction corresponded to the elevation level increasing from the river bank to the terrace. At the Mikhin Island the tendency was different. A coarser fraction was deposited on higher levels while the portion of clay fraction was at a minimum compared to the lower levels. To study the relationship between radionuclide activity concentrations and organic matter content, selected soil samples were subjected to extraction of the humic and fulvic acid fractions with a subsequent determination of radionuclides in the separated phases and the residue component. The air-dry sample was saturated with 0.1 M NaOH, humic acid was precipitated by 1 M HCl at pH=1. The separation resulted in three fractions of the fulvic acids, humic acids, and the residue containing the denuded mineral phase and the refractory organic residue. Radionuclides measured in the first fraction were believed to be the most mobile, those in the second fraction - subjected to the complexation
Fractional modelling for BBM-Burger equation by using new homotopy analysis transform method
Directory of Open Access Journals (Sweden)
Sunil Kumar
2014-10-01
Full Text Available The purpose of this study is to introduce a new analytical method namely, fractional homotopy analysis transform method (FHATM for series solution of the time fractional BBM-Burger equation. The homotopy analysis transform method is an innovative adjustment in Laplace transform algorithm (LTA for nonlinear fractional partial differential equation in fluid dynamics and makes the calculation much simpler. The proposed scheme finds the solutions of nonlinear problems without any discretization, restrictive assumptions and avoids the rounding off errors. The numerical solutions obtained by the proposed method indicate that the approach is easy to implement and computationally very attractive.
Directory of Open Access Journals (Sweden)
HASHEM SABERI NAJAFI
2016-07-01
Full Text Available Generalized differential transform method (GDTM is a powerful method to solve the fractional differential equations. In this paper, a new fractional model for systems with single degree of freedom (SDOF is presented, by using the GDTM. The advantage of this method compared with some other numerical methods has been shown. The analysis of new approximations, damping and acceleration of systems are also described. Finally, by reducing damping and analysis of the errors, in one of the fractional cases, we have shown that in addition to having a suitable solution for the displacement close to the exact one, the system enjoys acceleration once crossing the equilibrium point.
Energy Technology Data Exchange (ETDEWEB)
Odibat, Zaid [Prince Abdullah Bin Ghazi Faculty of Science and IT, Al-Balqa' Applied University, Salt 19117 (Jordan)], E-mail: odibat@bau.edu.jo; Momani, Shaher [Department of Mathematics, Mutah University, P.O. Box 7, Al-Karak (Jordan)], E-mail: shahermm@yahoo.com
2008-04-15
In this paper, a modification of He's homotopy perturbation method is presented. The new modification extends the application of the method to solve nonlinear differential equations of fractional order. In this method, which does not require a small parameter in an equation, a homotopy with an imbedding parameter p element of [0, 1] is constructed. The proposed algorithm is applied to the quadratic Riccati differential equation of fractional order. The results reveal that the method is very effective and convenient for solving nonlinear differential equations of fractional order.
Energy Technology Data Exchange (ETDEWEB)
Baudilio Coto; Carmen Martos; Jose L. Pena; Juan J. Espada; Maria D. Robustillo [Universidad Rey Juan Carlos, Madrid (Spain). Department of Chemical and Environmental Technology
2008-08-15
Wax precipitation is one of the most important flow assurance problems. Unfortunately, experimental data are very scarce to confirm existing models for prediction of such precipitation problem. This work reports a new experimental method. Multistage fractional wax precipitation was carried out by decreasing the temperature of crude oil. No solvent dilution was used, so the effect of solvent on temperature wax precipitation was avoided. The reproducibility of the method was tested with comparable results. The precipitation curve and the wax appearance temperature were obtained for two crude oils with different chemical nature using the reported method. 19 refs., 5 figs., 1 tab.
Avila Ruiz, Geraldine; Arts, Anke; Minor, Marcel; Schutyser, Maarten
2016-01-01
Combination of dry and aqueous fractionation is investigated to obtain protein-rich fractions from quinoa in a milder and more sustainable way compared to conventional wet fractionation. Dry fractionation of quinoa involved milling and subsequent air classification, generating a protein-enriched
Methods in industrial biotechnology for chemical engineers
Kandasamy, W B Vasantha
2008-01-01
In keeping with the definition that biotechnology is really no more than a name given to a set of techniques and processes, the authors apply some set of fuzzy techniques to chemical industry problems such as finding the proper proportion of raw mix to control pollution, to study flow rates, to find out the better quality of products. We use fuzzy control theory, fuzzy neural networks, fuzzy relational equations, genetic algorithms to these problems for solutions. When the solution to the problem can have certain concepts or attributes as indeterminate, the only model that can tackle such a situation is the neutrosophic model. The authors have also used these models in this book to study the use of biotechnology in chemical industries. This book has six chapters. First chapter gives a brief description of biotechnology. Second chapter deals will proper proportion of mix of raw materials in cement industries to minimize pollution using fuzzy control theory. Chapter three gives the method of determination of te...
Frontier in nanoscale flows fractional calculus and analytical methods
Lewis, Roland; Liu, Hong-yan
2014-01-01
This ebook covers the basic properties of nanoscale flows, and various analytical and numerical methods for nanoscale flows and environmental flows. This ebook is a good reference not only for audience of the journal, but also for various communities in mathematics, nanotechnology and environmental science.
Spectroscopic Chemical Analysis Methods and Apparatus
Hug, William F.; Reid, Ray D.
2012-01-01
This invention relates to non-contact spectroscopic methods and apparatus for performing chemical analysis and the ideal wavelengths and sources needed for this analysis. It employs deep ultraviolet (200- to 300-nm spectral range) electron-beam-pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor lightemitting devices, and hollow cathode metal ion lasers. Three achieved goals for this innovation are to reduce the size (under 20 L), reduce the weight [under 100 lb (.45 kg)], and reduce the power consumption (under 100 W). This method can be used in microscope or macroscope to provide measurement of Raman and/or native fluorescence emission spectra either by point-by-point measurement, or by global imaging of emissions within specific ultraviolet spectral bands. In other embodiments, the method can be used in analytical instruments such as capillary electrophoresis, capillary electro-chromatography, high-performance liquid chromatography, flow cytometry, and related instruments for detection and identification of unknown analytes using a combination of native fluorescence and/or Raman spectroscopic methods. This design provides an electron-beampumped semiconductor radiation-producing method, or source, that can emit at a wavelength (or wavelengths) below 300 nm, e.g. in the deep ultraviolet between about 200 and 300 nm, and more preferably less than 260 nm. In some variations, the method is to produce incoherent radiation, while in other implementations it produces laser radiation. In some variations, this object is achieved by using an AlGaN emission medium, while in other implementations a diamond emission medium may be used. This instrument irradiates a sample with deep UV radiation, and then uses an improved filter for separating wavelengths to be detected. This provides a multi-stage analysis of the sample. To avoid the difficulties related to producing deep UV semiconductor sources, a pumping approach has been developed that uses
Mengyue Wang; Ke Li; Yuxiao Nie; Yingfang Wei; Xiaobo Li
2012-01-01
Urtica atrichocaulis, an endemic plant to China, is commonly used to treat rheumatoid arthritis even though its pharmaceutical activities and chemical constituents were not studied. Herein, we reported our investigations on the chemical compositions of the phenolic compounds-rich fraction from U. atrichocaulis (TFUA) and their antirheumatoid arthritis activities. We found that the TFUA significantly inhibited the adjuvant-induced rats arthritis, carrageenin-induced rats paw edema, cotton pell...
International Nuclear Information System (INIS)
The laboratory methodology and preliminary findings from an ongoing characterisation study of Water Accommodated Fraction solutions (WAF) (water systems with dissolved oil components, which is essentially free of dispersed oil droplets) derived from standardised low energy mixing of oils in seawater is presented. The study emphasises a tight connection between chemical characterisation and toxicological testing of WAF, and aims at obtaining improved and realistic data on potential environmental effects in the water column after an oil spill situation. Various oil types and the aspect of weathering (evaporative loss and photolysis) of oil is incorporated in the study. Preliminary results have identified large variation in the composition and toxicity of WAFs depending on the type of crude, oil loading rate (oil:water ratio) and weathering degree of the oils. Data from the study will be used for improving algorithms in present fate and effect models, which again will be used as quantitative tools in future damage assessment studies and in Net Environmental Benefit Analysis of response alternatives in various spill scenarios. (author)
Energy Technology Data Exchange (ETDEWEB)
Gutierrrez, L.F.; Rosada, L.M.; Jimenez, A.
2011-07-01
The seeds of Sacha inchi (Plukenetia volubilis L.) from Colombia were analyzed for their main chemical composition. Sacha inchi seeds (SIS) were rich in oil (41.4%) and protein (24.7%). The main minerals present in SIS were potassium (5563.5 ppm), magnesium (3210 ppm) and calcium (2406 ppm). A fatty acid analysis revealed that a-linolenic (50.8%) and linoleic (33.4%) acids were the main fatty acids in Sacha inchi oil (SIO). The lipid fractionation of SIO, obtained by solid phase extraction, yielded mainly neutral lipids (97.2%), and lower amounts of free fatty acids (1.2%) and phospholipids (0.8%). The physicochemical properties of the oil include: saponification number 185.2; iodine value 193.1; density 0.9187 g/cm3, refractive index 0.4791 and viscosity of 35.4 mPa.s. The melting profiles of SIO were characterized by the presence of one wide endothermic peak with a melting enthalpy of 23.2 J/g. Our results indicate that Sacha inchi is an important new crop with applications in the food and pharmaceutical industries. (Author).
International Nuclear Information System (INIS)
The seeds of Sacha inchi (Plukenetia volubilis L.) from Colombia were analyzed for their main chemical composition. Sacha inchi seeds (SIS) were rich in oil (41.4%) and protein (24.7%). The main minerals present in SIS were potassium (5563.5 ppm), magnesium (3210 ppm) and calcium (2406 ppm). A fatty acid analysis revealed that a-linolenic (50.8%) and linoleic (33.4%) acids were the main fatty acids in Sacha inchi oil (SIO). The lipid fractionation of SIO, obtained by solid phase extraction, yielded mainly neutral lipids (97.2%), and lower amounts of free fatty acids (1.2%) and phospholipids (0.8%). The physicochemical properties of the oil include: saponification number 185.2; iodine value 193.1; density 0.9187 g/cm3, refractive index 0.4791 and viscosity of 35.4 mPa.s. The melting profiles of SIO were characterized by the presence of one wide endothermic peak with a melting enthalpy of 23.2 J/g. Our results indicate that Sacha inchi is an important new crop with applications in the food and pharmaceutical industries. (Author).
Melancon, Sonia; Fryer, Brian J; Markham, James L
2009-06-01
The fractionation of metals from water to otolith is an area of research that has received relatively limited attention, especially in freshwater systems. The objectives of the present research were to study the metal partitioning between otolith and endolymph of two freshwater species: Lake trout (Salvelinus namaycush), and burbot (Lota lota). We also included the chemical analyses of water and blood from fish of the same species collected in the same area but during different years. These results provide insight regarding the partition of metals between water and fish. This is one of the first studies to provide a range of trace metal concentrations for endolymph and the growing otolith (both aragonite and vaterite) and to directly measure otolith-endolymph partition coefficients for freshwater fish. The trace elements (Mg, Sr, and Ba) most often used as otolith elemental tracers were the ones with the lowest uptake from water to blood. We found that endolymph and whole blood had similar metal concentrations, with Mg and Fe being the only elements enriched in whole blood. Results showed few significant differences in trace metal content between wild lake trout and burbot endolymph (except for K, Mg, and Ba), but significant differences existed between their aragonitic otoliths. These results suggest two different crystallization processes in these species or the presence of different proteins (and/or organic matrices) that would selectively influence elemental incorporation in the otoliths. PMID:19154085
Method for forming a chemical microreactor
Morse, Jeffrey D.; Jankowski, Alan
2009-05-19
Disclosed is a chemical microreactor that provides a means to generate hydrogen fuel from liquid sources such as ammonia, methanol, and butane through steam reforming processes when mixed with an appropriate amount of water. The microreactor contains capillary microchannels with integrated resistive heaters to facilitate the occurrence of catalytic steam reforming reactions. Two distinct embodiment styles are discussed. One embodiment style employs a packed catalyst capillary microchannel and at least one porous membrane. Another embodiment style employs a porous membrane with a large surface area or a porous membrane support structure containing a plurality of porous membranes having a large surface area in the aggregate, i.e., greater than about 1 m.sup.2/cm.sup.3. Various methods to form packed catalyst capillary microchannels, porous membranes and porous membrane support structures are also disclosed.
Chemical decontamination method for radioactive metal waste
International Nuclear Information System (INIS)
The invention relates to a decontamination method for radioactive metal waste products derived from equipment that handles radioactive materials whose surfaces have been contaminated; in particular it concerns a decontamination method that reduces the amount of radioactive waste by decontaminating radioactive waste substances to a level of radioactivity in line with normal waste products. In order to apply chemical decontamination to metal waste products whose surfaces are divided into carbon steel waste and stainless steel waste; the carbon steel waste is treated using only a primary process in which the waste is immersed in a sulfuric acid solution, while the stainless steel waste must be treated with both the primary process and then electrolytically reduces it for a specific length of time and a secondary process that uses a solution of sulfuric acid mixed with oxidizing metal salts. The method used to categorize metal waste into carbon steel waste and stainless steel waste involves determining the presence, or absence, of magnetism. Voltage is applied for a fixed duration; once that has stopped, electrolytic reduction repeats the operative cycle of applying, then stopping voltage until the potential of the radioactive metal waste is retained in the active region. 1 fig. 2 tabs
Chemical Methods for Peptide and Protein Production
Directory of Open Access Journals (Sweden)
Istvan Toth
2013-04-01
Full Text Available Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.
Asma Ali Elbeleze; Adem Kılıçman; Bachok M. Taib
2013-01-01
The homotopy perturbation method, Sumudu transform, and He’s polynomials are combined to obtain the solution of fractional Black-Scholes equation. The fractional derivative is considered in Caputo sense. Further, the same equation is solved by homotopy Laplace transform perturbation method. The results obtained by the two methods are in agreement. The approximate analytical solution of Black-Scholes is calculated in the form of a convergence power series with easily computable components. ...
Directory of Open Access Journals (Sweden)
Samia Bushnaq
2014-01-01
Full Text Available We present a new version of the reproducing kernel Hilbert space method (RKHSM for the solution of systems of fractional integrodifferential equations. In this approach, the solution is obtained as a convergent series with easily computable components. Several illustrative examples are given to demonstrate the effectiveness of the present method. The method described in this paper is expected to be further employed to solve similar nonlinear problems in fractional calculus.
Sivapatham, Paramasivam; Lettimore, Jon M; Alva, Ashok K; Jayaraman, Kuppuswamy; Harper, Legia M
2014-09-19
Heavy metals are potentially toxic to human life and the environment. Metal toxicity depends on chemical associations in soil. Understanding the chemical association of trace elements in soils amended with biosolids is very important since it determines their availability within rhizosphere and mobility beyond the rhizosphere. A sequential extraction method was used to determine the various chemical associations [labile (exchangeable + sorbed), organic, carbonates, and sulfides] of Cu, Zn, Cd, Cr, and Pb at the end of sorghum-sudan grass growth (65d) in Candler fine sand (pH = 6.8) and in Ogeechee loamy sand (pH = 5.2) amended with wastewater treatment sludge (WWTS) obtained from two different sources at application rates of 0, 24.7, 49.4, 98.8, and 148.2 Mg ha(-1). Results of this study indicated that irrespective of the soil type, Cu, Cd, Cr, and Pb in the labile fractions (exchangeable + sorbed) were in the range of 0-3.0 mg kg(-1) and the amount for Zn was in the range of 0.2-6.6 mg kg(-1). Therefore, their availability to plants and mobility beyond rhizosphere would be substantially low unless further transformations occur from other fractions. Results also indicated that the presence of substantial amounts of trace elements studied were in sulfide (HNO3) fraction and in organic (NaOH) fraction irrespective of soil type with the exception of Pb which was mainly present as carbonate (Na2EDTA) fraction and the remaining Pb equally as sulfide (HNO3) and organic (NaOH) fractions. Furthermore, results indicated that Cd was mainly present as carbonate (Na2EDTA) fraction. Irrespective of soil type, source and rate of WWTS application, summation of quantities of various fractions of all the trace elements studied through sequential extraction procedure were 1 to 25 % lower than that of total recoverable quantities of these trace elements determined on acid digestion described by US EPA method 3050 B. It was further evident that growing sorghum sudan grass for 65-d
Diggs, Angela; Balachandar, S.
2016-05-01
The present work addresses numerical methods required to compute particle volume fraction or number density. Local volume fraction of the lth particle, αl, is the quantity of foremost importance in calculating the gas-mediated particle-particle interaction effect in multiphase flows. A general multiphase flow with a distribution of Lagrangian particles inside a fluid flow discretized on an Eulerian grid is considered. Particle volume fraction is needed both as a Lagrangian quantity associated with each particle and also as an Eulerian quantity associated with the grid cell for Eulerian-Lagrangian simulations. In Grid-Based (GB) methods the particle volume fraction is first obtained within each grid cell as an Eulerian quantity and then the local particle volume fraction associated with any Lagrangian particle can be obtained from interpolation. The second class of methods presented are Particle-Based (PB) methods, where particle volume fraction will first be obtained at each particle as a Lagrangian quantity, which then can be projected onto the Eulerian grid. Traditionally, the GB methods are used in multiphase flow, but sub-grid resolution can be obtained through use of the PB methods. By evaluating the total error, and its discretization, bias and statistical error components, the performance of the different PB methods is compared against several common GB methods of calculating volume fraction. The standard von Neumann error analysis technique has been adapted for evaluation of rate of convergence of the different methods. The discussion and error analysis presented focus on the volume fraction calculation, but the methods can be extended to obtain field representations of other Lagrangian quantities, such as particle velocity and temperature.
A semi-analytical finite element method for a class of time-fractional diffusion equations
Sun, HongGuang; Sze, K Y
2011-01-01
As fractional diffusion equations can describe the early breakthrough and the heavy-tail decay features observed in anomalous transport of contaminants in groundwater and porous soil, they have been commonly employed in the related mathematical descriptions. These models usually involve long-time range computation, which is a critical obstacle for its application, improvement of the computational efficiency is of great significance. In this paper, a semi-analytical method is presented for solving a class of time-fractional diffusion equations which overcomes the critical long-time range computation problem of time fractional differential equations. In the procedure, the spatial domain is discretized by the finite element method which reduces the fractional diffusion equations into approximate fractional relaxation equations. As analytical solutions exist for the latter equations, the burden arising from long-time range computation can effectively be minimized. To illustrate its efficiency and simplicity, four...
Chemical Reactivity as Described by Quantum Chemical Methods
De Proft, F.; Geerlings, P.
2002-01-01
Abstract: Density Functional Theory is situated within the evolution of Quantum Chemistry as a facilitator of computations and a provider of new, chemical insights. The importance of the latter branch of DFT, conceptual DFT is highlighted following Parr's dictum "to calculate a molecule is not to understand it". An overview is given of the most important reactivity descriptors and the principles they are couched in. Examples are given on the evolution of the structure-property-wave function t...
A New Pseudoinverse Matrix Method For Balancing Chemical Equations And Their Stability
Energy Technology Data Exchange (ETDEWEB)
Risteski, Ice B. [2 Milepost Place, Ontario (Canada)
2008-06-15
In this work is given a new pseudoniverse matrix method for balancing chemical equations. Here offered method is founded on virtue of the solution of a Diophantine matrix equation by using of a Moore-Penrose pseudoinverse matrix. The method has been tested on several typical chemical equations and found to be very successful for the all equations in our extensive balancing research. This method, which works successfully without any limitations, also has the capability to determine the feasibility of a new chemical reaction, and if it is feasible, then it will balance the equation. Chemical equations treated here possess atoms with fractional oxidation numbers. Also, in the present work are introduced necessary and sufficient criteria for stability of chemical equations over stability of their extended matrices.
Weighted Average Finite Difference Methods for Fractional Reaction-Subdiffusion Equation
Directory of Open Access Journals (Sweden)
Nasser Hassen SWEILAM
2014-04-01
Full Text Available In this article, a numerical study for fractional reaction-subdiffusion equations is introduced using a class of finite difference methods. These methods are extensions of the weighted average methods for ordinary (non-fractional reaction-subdiffusion equations. A stability analysis of the proposed methods is given by a recently proposed procedure similar to the standard John von Neumann stability analysis. Simple and accurate stability criterion valid for different discretization schemes of the fractional derivative, arbitrary weight factor, and arbitrary order of the fractional derivative, are given and checked numerically. Numerical test examples, figures, and comparisons have been presented for clarity.doi:10.14456/WJST.2014.50
International Nuclear Information System (INIS)
In this article, two reliable techniques, Haar wavelet method and optimal homotopy asymptotic method (OHAM) are presented. Haar wavelet method is an efficient numerical method for the numerical solution of fractional order partial differential equation like Fisher type. The approximate solutions of the fractional Fisher type equation are compared with the optimal homotopy asymptotic method as well as with the exact solutions. Comparisons between the obtained solutions with the exact solutions exhibit that both the featured methods are effective and efficient in solving nonlinear problems. However, the results indicate that OHAM provides more accurate value than Haar wavelet method
Semiclassical methods in chemical reaction dynamics
International Nuclear Information System (INIS)
Semiclassical approximations, simple as well as rigorous, are formulated in order to be able to describe gas phase chemical reactions in large systems. We formulate a simple but accurate semiclassical model for incorporating multidimensional tunneling in classical trajectory simulations. This model is based on the existence of locally conserved actions around the saddle point region on a multidimensional potential energy surface. Using classical perturbation theory and monitoring the imaginary action as a function of time along a classical trajectory we calculate state-specific unimolecular decay rates for a model two dimensional potential with coupling. Results are in good comparison with exact quantum results for the potential over a wide range of coupling constants. We propose a new semiclassical hybrid method to calculate state-to-state S-matrix elements for bimolecular reactive scattering. The accuracy of the Van Vleck-Gutzwiller propagator and the short time dynamics of the system make this method self-consistent and accurate. We also go beyond the stationary phase approximation by doing the resulting integrals exactly (numerically). As a result, classically forbidden probabilties are calculated with purely real time classical trajectories within this approach. Application to the one dimensional Eckart barrier demonstrates the accuracy of this approach. Successful application of the semiclassical hybrid approach to collinear reactive scattering is prevented by the phenomenon of chaotic scattering. The modified Filinov approach to evaluating the integrals is discussed, but application to collinear systems requires a more careful analysis. In three and higher dimensional scattering systems, chaotic scattering is suppressed and hence the accuracy and usefulness of the semiclassical method should be tested for such systems
Semiclassical methods in chemical reaction dynamics
Energy Technology Data Exchange (ETDEWEB)
Keshavamurthy, S.
1994-12-01
Semiclassical approximations, simple as well as rigorous, are formulated in order to be able to describe gas phase chemical reactions in large systems. We formulate a simple but accurate semiclassical model for incorporating multidimensional tunneling in classical trajectory simulations. This model is based on the existence of locally conserved actions around the saddle point region on a multidimensional potential energy surface. Using classical perturbation theory and monitoring the imaginary action as a function of time along a classical trajectory we calculate state-specific unimolecular decay rates for a model two dimensional potential with coupling. Results are in good comparison with exact quantum results for the potential over a wide range of coupling constants. We propose a new semiclassical hybrid method to calculate state-to-state S-matrix elements for bimolecular reactive scattering. The accuracy of the Van Vleck-Gutzwiller propagator and the short time dynamics of the system make this method self-consistent and accurate. We also go beyond the stationary phase approximation by doing the resulting integrals exactly (numerically). As a result, classically forbidden probabilties are calculated with purely real time classical trajectories within this approach. Application to the one dimensional Eckart barrier demonstrates the accuracy of this approach. Successful application of the semiclassical hybrid approach to collinear reactive scattering is prevented by the phenomenon of chaotic scattering. The modified Filinov approach to evaluating the integrals is discussed, but application to collinear systems requires a more careful analysis. In three and higher dimensional scattering systems, chaotic scattering is suppressed and hence the accuracy and usefulness of the semiclassical method should be tested for such systems.
International Nuclear Information System (INIS)
In relation to the development of a solid target of high intensity neutron source, plasma-facing components of fusion reactor and so forth, it is indispensable to estimate the void fraction for high-heat-load subcooled flow boiling of water. Since the existing prediction method of void fraction is based on the database for tubes, it is necessary to investigate extendibility of the existing prediction method to narrow-gap rectangular channels that is used in the high-heat-load devices. However, measurement method of void fraction in the narrow-gap rectangular channel has not been established yet because of the difficulty of measurement. The objectives of this investigation are development of a new system for bubble visualization and void fraction measurement on subcooled flow boiling in narrow-gap rectangular channels using the neutron radiography, and establishment of void fraction database by using this measurement system. This report describes the void fraction measurement method by the neutron radiography technique, and summarizes the measured void fraction data in one-side heated narrow-gap rectangular channels at subcooled boiling condition. (author)
Non-asymptotic fractional order differentiators via an algebraic parametric method
Liu, Dayan
2012-08-01
Recently, Mboup, Join and Fliess [27], [28] introduced non-asymptotic integer order differentiators by using an algebraic parametric estimation method [7], [8]. In this paper, in order to obtain non-asymptotic fractional order differentiators we apply this algebraic parametric method to truncated expansions of fractional Taylor series based on the Jumarie\\'s modified Riemann-Liouville derivative [14]. Exact and simple formulae for these differentiators are given where a sliding integration window of a noisy signal involving Jacobi polynomials is used without complex mathematical deduction. The efficiency and the stability with respect to corrupting noises of the proposed fractional order differentiators are shown in numerical simulations. © 2012 IEEE.
Chemically fractionated fission-xenon in meteorites and on the earth
Shukolyukov, Yuri A.; Jessberger, Elmar K.; Meshik, Alexander P.; Vu Minh, Dang; Jordan, Jimmy L.
1994-07-01
This is a report on the nature of isotopically anomalous xenon, which has been detected in two Ca-Al-rich inclusions of the Allende carbonaceous chondrite. It is extremely enriched in 132Xe, 129Xe, and to a lesser extent in 131Xe. Similar large excesses of 132Xe as well as of 131Xe, 134Xe, and 129Xe have previously been found in material processed in a natural nuclear reactor (Oklo phenomenon). Excess of these isotopes had also been encountered in MORB-glasses, in an ancient Greenland anorthosite. Thus, this Xe-type, which had previously been termed "alien" ( JORDON et al., 1980a) does not seem to be unique. To determine the origin of "alien" Xe, we analysed Xe (a) in neutron irradiated pitchblende and in the irradiation capsule, (b) in non-irradiated extremely fine-grained pitchblende (so-called Colorado-type deposit), and (c) in sandstone taken from the epicentre of an atomic explosion. In addition, the isotopic composition of xenon released by stepwise degassing and after selective dissolving of rocks from the Oklo natural reactor was determined. The results of these dedicated experiments demonstrate that the formation of alien Xe is due to the migration of the radioactive precursors of the stable isotopes 134Xe, 132Xe, 131Xe, and 129Xe. Due to this reason we now call it CFF-Xe - Chemically Fractionated Fission Xenon. Prerequisites for its formation are the simultaneous prevalence of two conditions: (1) fission (of 238U, 235U, and/ or 244Pu) and (2) a physicochemical environment (temperature, pressure, fluidity) at which the precursors of xenon (mainly Te and I) are mobile. Taking into account the occurrence of xenon in meteorites and terrestrial rocks, not all excesses of 129Xe in mantle rocks and natural gases are necessarily connected with the decay of primordial 129I.
Energy Technology Data Exchange (ETDEWEB)
Irvine, Kim N.; Perrelli, Mary F. [State Univ. of New Yrok, Buffalo, NY (United States). Geography and Planning Dept., Buffalo State; Ngoen-klan, Ratchadawan [Chiang Mai Univ. (Thailand). Dept. of Parasitology; Droppo, Ian G. [Water Science and Technology Directorate, Science and Technology Branch, Environment Canada, Burlington, ONT (Canada). Aquatic Ecosystem Management Research Div.
2009-08-15
Background, aim and scope: Street sediment samples were collected at 50 locations in a mixed land use area of Hamilton, Ontario, Canada, and metal levels were analyzed using a sequential extraction procedure for different particle size classes to provide an estimate of potential toxicity as well as the potential for treatment through best management practices (BMPs). Methodology: The street sediment samples were dry sieved into four different particle size categories and a sequential extraction procedure was done on each size category following the methodology proposed by Tessier et al. 1979 using a Hitachi 180-80 Polarized Zeeman Atomic Absorption Spectrophotometer. Results and discussion: Analysis of variance, post hoc least-significant difference tests, and kriging analysis showed that spatially Mn and Fe levels were associated with a well-defined heavy industrial area that includes large iron- and steel-making operations; Cu and Pb were associated with both the industrial and high-volume traffic areas, while Zn tended to be more associated with high-volume traffic areas. The potential bioavailability of the metals, based on the sum of chemical fractions 1 (exchangeable) and 2 (carbonate-bound), decreased in order: Zn > Cd > Mn > Pb > Cu > Fe. Based on aquatic sediment quality guidelines, there is some concern regarding the potential impact of the street sediment when runoff reaches receiving waters. Conclusions: It is possible that a combination of BMPs, including street sweeping and constructed wetlands, could help to reduce street sediment impact on environmental quality in the Hamilton region. The data presented here would be important in developing and optimizing the design of these BMPs. (orig.)
Rafiq, Saima; Huma, Nuzhat; Pasha, Imran; Sameen, Aysha; Mukhtar, Omer; Khan, Muhammad Issa
2016-07-01
Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat (6.82%±0.04%), solid-not-fat (11.24%±0.02%), total solids (18.05%±0.05%), protein (5.15%±0.06%) and casein (3.87%±0.04%) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk (0.80%±0.03%), buffalo (0.68%±0.02%) and sheep (0.66%±0.02%) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow (108±2.3 mg/g), camel (96±2.2 mg/g) and buffalo (90±2.4 mg/g) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products. PMID:26954163
Apparatus and method for rapid separation and detection of hydrocarbon fractions in a fluid stream
Sluder, Charles S.; Storey, John M.; Lewis, Sr., Samuel A.
2013-01-22
An apparatus and method for rapid fractionation of hydrocarbon phases in a sample fluid stream are disclosed. Examples of the disclosed apparatus and method include an assembly of elements in fluid communication with one another including one or more valves and at least one sorbent chamber for removing certain classifications of hydrocarbons and detecting the remaining fractions using a detector. The respective ratios of hydrocarbons are determined by comparison with a non separated fluid stream.
Cave, Mark; Wragg, Joanna; Gowing, Charles; Gardner, Amanda
2015-08-01
The study used 276 urban soils and 447 rural soils collected from in and around the UK town of Northampton and focussed on the fractionation of Pb. The Pb fractionation obtained from total element data was compared to the fractionation of Pb in a subset of 10 urban soils obtained using a sequential extraction method. The fractionation of the Pb from the total element data and from the sequential extractions was estimated using a self-modelling mixture resolution statistical model. The bioaccessibility of Pb in a subset of 50 of the urban soils, as measured using the unified BARGE method, was shown to be quantitatively linked with Pb fractionation from both the total element and the sequential extraction data. Three intrinsic soil components from the regional total element data model and one physico-chemical component from the sequential extraction data model were identified as the sources of bioaccessible Pb. The source of bioaccessible Pb in both rural and urban soils was tentatively identified as a fine-grained pyromorphite mineral. PMID:25840564
Analysis of a time fractional wave-like equation with the homotopy analysis method
International Nuclear Information System (INIS)
The time fractional wave-like differential equation with a variable coefficient is studied analytically. By using a simple transformation, the governing equation is reduced to two fractional ordinary differential equations. Then the homotopy analysis method is employed to derive the solutions of these equations. The accurate series solutions are obtained. Especially, when hf=hg=-1, these solutions are exactly the same as those results given by the Adomian decomposition method. The present work shows the validity and great potential of the homotopy analysis method for solving nonlinear fractional differential equations. The basic idea described in this Letter is expected to be further employed to solve other similar nonlinear problems in fractional calculus
Formulation and Application of Quantum Monte Carlo Method to Fractional Quantum Hall Systems
Suzuki, Sei; Nakajima, Tatsuya
2003-01-01
Quantum Monte Carlo method is applied to fractional quantum Hall systems. The use of the linear programming method enables us to avoid the negative-sign problem in the Quantum Monte Carlo calculations. The formulation of this method and the technique for avoiding the sign problem are described. Some numerical results on static physical quantities are also reported.
Chemical Reactivity as Described by Quantum Chemical Methods
Directory of Open Access Journals (Sweden)
F. De Proft
2002-04-01
Full Text Available Abstract: Density Functional Theory is situated within the evolution of Quantum Chemistry as a facilitator of computations and a provider of new, chemical insights. The importance of the latter branch of DFT, conceptual DFT is highlighted following Parr's dictum "to calculate a molecule is not to understand it". An overview is given of the most important reactivity descriptors and the principles they are couched in. Examples are given on the evolution of the structure-property-wave function triangle which can be considered as the central paradigm of molecular quantum chemistry to (for many purposes a structure-property-density triangle. Both kinetic as well as thermodynamic aspects can be included when further linking reactivity to the property vertex. In the field of organic chemistry, the ab initio calculation of functional group properties and their use in studies on acidity and basicity is discussed together with the use of DFT descriptors to study the kinetics of SN2 reactions and the regioselectivity in Diels Alder reactions. Similarity in reactivity is illustrated via a study on peptide isosteres. In the field of inorganic chemistry non empirical studies of adsorption of small molecules in zeolite cages are discussed providing Henry constants and separation constants, the latter in remarkable good agreement with experiments. Possible refinements in a conceptual DFT context are presented. Finally an example from biochemistry is discussed : the influence of point mutations on the catalytic activity of subtilisin.
A Fully Discrete Galerkin Method for a Nonlinear Space-Fractional Diffusion Equation
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Yunying Zheng
2011-01-01
Full Text Available The spatial transport process in fractal media is generally anomalous. The space-fractional advection-diffusion equation can be used to characterize such a process. In this paper, a fully discrete scheme is given for a type of nonlinear space-fractional anomalous advection-diffusion equation. In the spatial direction, we use the finite element method, and in the temporal direction, we use the modified Crank-Nicolson approximation. Here the fractional derivative indicates the Caputo derivative. The error estimate for the fully discrete scheme is derived. And the numerical examples are also included which are in line with the theoretical analysis.
International Nuclear Information System (INIS)
Igneous rock successions can be investigated with respect to their genetic coherence or to the role in fractional crystallization during their generation, respectively, by evaluating element concentration correlations. It is shown that the existence of a linear relation between element concentrations or their logarithms is only a necessary, but not a sufficient condition for fractional crystallization as the dominating factor of graduating element concentrations. The comparison of the slope of such correlation lines with the slope calculated on the basis of the distribution coefficients evaluated by using Schuetze's 18O index reveals whether fractional crystallization is dominant in graduating element concentrations in igneous rocks. Several applications are given. (author)
Chemical functional use -- the functional role a chemical plays in processes or products -- may be a useful heuristic for predicting human exposure potential in that it comprises information about the compound's likely physical properties and the product formulations or articles ...
New Iterative Method for Fractional Gas Dynamics and Coupled Burger’s Equations
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Mohamed S. Al-luhaibi
2015-01-01
Full Text Available This paper presents the approximate analytical solutions to solve the nonlinear gas dynamics and coupled Burger’s equations with fractional time derivative. By using initial values, the explicit solutions of the equations are solved by using a reliable algorithm. Numerical results show that the new iterative method is easy to implement and accurate when applied to time-fractional partial differential equations.
The Operator Method for Solving The Fractional Fokker-Planck Equation
International Nuclear Information System (INIS)
The operator method has been used to solve the fractional Fokker-Planck equation which was recently formulated as a model for the anomalous transport process. Two classes of special interest of fractional F-P equations coming from plasma physics and charged particle transport problem has been considered. It is shown that the mean square-displacement 2(t) > satisfy the universal power law characterized the anomalous time evolution e.i. 2(t) >tγ, 0 < γ < 1
Audette, Yuki; O'Halloran, Ivan P; Evans, Les J; Voroney, R Paul
2016-06-01
A sequential fractionation method proposed by Jiang and Gu (1989) distinguished three types of calcium phosphates (Ca-P) according to their different plant availabilities. Three extractants, NaHCO3, NH4Ac, and H2SO4 were used to extract Ca2-P, Ca8-P, and Ca10-P types, respectively, from soil. This sequential fractionation method was tested and modified for analyzing the P chemistry of a calcareous soil. The solubility test and the model diagrams of the stability of the major Ca-P minerals showed that NaHCO3 was able to extract brushite (Ca2-P type), and NH4Ac extracted brushite and β-tricalcium P (Ca8-P type) as well as hydroxyapatite (Ca10-P type). Therefore the P forms targeted by extraction with NH4Ac should include both Ca8-and Ca10-P types. The sum of the P extracted by all extractants in the sequential fractionation method in the calcareous soil was in agreement with the total P measured by the perchloric acid digestion method. A proportion of organic P measured by the sequential fractionation method was in agreement with the result from solution (31)P NMR spectroscopy. This study showed that the modified sequential fractionation method and its target P forms would be useful for quantifying and characterizing inorganic and organic P in a calcareous soil, even though it should be used in combination with other techniques, such as solution (31)P NMR spectroscopy. PMID:26994430
New analytical exact solutions of time fractional KdV–KZK equation by Kudryashov methods
S Saha, Ray
2016-04-01
In this paper, new exact solutions of the time fractional KdV–Khokhlov–Zabolotskaya–Kuznetsov (KdV–KZK) equation are obtained by the classical Kudryashov method and modified Kudryashov method respectively. For this purpose, the modified Riemann–Liouville derivative is used to convert the nonlinear time fractional KdV–KZK equation into the nonlinear ordinary differential equation. In the present analysis, the classical Kudryashov method and modified Kudryashov method are both used successively to compute the analytical solutions of the time fractional KdV–KZK equation. As a result, new exact solutions involving the symmetrical Fibonacci function, hyperbolic function and exponential function are obtained for the first time. The methods under consideration are reliable and efficient, and can be used as an alternative to establish new exact solutions of different types of fractional differential equations arising from mathematical physics. The obtained results are exhibited graphically in order to demonstrate the efficiencies and applicabilities of these proposed methods of solving the nonlinear time fractional KdV–KZK equation.
A novel approach for solving fractional Fisher equation using differential transform method
Indian Academy of Sciences (India)
MIRZAZADEH M
2016-05-01
In the present paper, an analytic solution of nonlinear fractional Fisher equation is deduced with the help of the powerful differential transform method (DTM). To illustrate the method, two examples have been prepared. The method for this equation has led to an exact solution. The reliability, simplicity and cost-effectiveness of the method are confirmed by applying this method on different forms of functional equations.
Quantification of chemical contaminants in the paper and board fractions of municipal solid waste
DEFF Research Database (Denmark)
Pivnenko, Kostyantyn; Olsson, Mikael Emil; Götze, Ramona;
2016-01-01
Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on...... the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re......-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households...
Jean Sérgio Rosset; Jolimar Antonio Schiavo; Ricardo Augusto Rezende Atanázio
2014-01-01
Mechanized harvesting maintenance of trash from cane sugar and soil application of waste as vinasse and filter cake can improve the system of crop yield. Thus, this study aimed to evaluate the changes in the chemical, the stock of total organic carbon and humified organic matter fractions in an Oxisol cultivated with cane sugar with the following management systems: with sugarcane vinasse application (CCV), without application of burnt cane waste (CQS), with burnt cane vinasse application (CQ...
Cáceres, Rafaela; Flotats, Xavier; Marfà, Oriol
2006-01-01
Replacement of peat as a growing medium by a renewable material, such as an organic waste, is an issue of concern since harvesting of peat has a considerable environmental impact and, actually, it is a non-renewable resource. Cattle manure is a readily available organic waste, which means that once it goes through the composting process, it can be used as an alternative to peat, specifically, the solid fraction obtained from mechanical liquid-solid separation of cattle slurry (SF). Studies have shown it to be suitable for such uses. The purpose of this study was to detect possible changes in the physicochemical and chemical properties of SF when it is composted using different aeration strategies, with an emphasis on the changes that would make it feasible for use as a substrate. With this aim in mind, an experiment was designed with three aeration strategies that would be used during composting. The first consisted of applying air through a static method (forced ventilation). The second involved improving aeration by adding a bulking agent and a dynamic turning method. In the third strategy, aeration was carried out by turning (control). The results show that the different aeration strategies had a clear effect on the evolution of pH, electrical conductivity (EC), nitrate-N, ammonia-N and bicarbonate content. Nitrification was favored under good aeration conditions using the static composting method, probably due to the greater availability of ammonia-N that was transformed into nitrate-N. In general, the low buffering capacity allowed for a reduction of the pH during the curing stage of composting (in conjunction with low temperatures during this period), a characteristic that favors the use of this compost as a growing medium. We also conclude that measuring bicarbonate levels during composting could be used as an indicator of the possible acidification of the material and as a way of evaluating the level of material aeration. PMID:16146687
Directory of Open Access Journals (Sweden)
S. Das
2013-12-01
Full Text Available In this article, optimal homotopy-analysis method is used to obtain approximate analytic solution of the time-fractional diffusion equation with a given initial condition. The fractional derivatives are considered in the Caputo sense. Unlike usual Homotopy analysis method, this method contains at the most three convergence control parameters which describe the faster convergence of the solution. Effects of parameters on the convergence of the approximate series solution by minimizing the averaged residual error with the proper choices of parameters are calculated numerically and presented through graphs and tables for different particular cases.
Space-fractional advection-dispersion equations by the Kansa method
Pang, Guofei; Chen, Wen; Fu, Zhuojia
2015-07-01
The paper makes the first attempt at applying the Kansa method, a radial basis function meshless collocation method, to the space-fractional advection-dispersion equations, which have recently been observed to accurately describe solute transport in a variety of field and lab experiments characterized by occasional large jumps with fewer parameters than the classical models of integer-order derivative. However, because of non-local property of integro-differential operator of space-fractional derivative, numerical solution of these novel models is very challenging and little has been reported in literature. It is stressed that local approximation techniques such as the finite element and finite difference methods lose their sparse discretization matrix due to this non-local property. Thus, the global methods appear to have certain advantages in numerical simulation of these non-local models because of their high accuracy and smaller size resultant matrix equation. Compared with the finite difference method, popular in the solution of fractional equations, the Kansa method is a recent meshless global technique and is promising for high-dimensional irregular domain problems. In this study, the resultant matrix of the Kansa method is accurately calculated by the Gauss-Jacobi quadrature rule. Numerical results show that the Kansa method is highly accurate and computationally efficient for space-fractional advection-dispersion problems.
Directory of Open Access Journals (Sweden)
M. H. Heydari
2013-01-01
Full Text Available An efficient Chebyshev wavelets method for solving a class of nonlinear fractional integrodifferential equations in a large interval is developed, and a new technique for computing nonlinear terms in such equations is proposed. Existence of a unique solution for such equations is proved. Convergence and error analysis of the proposed method are investigated. Moreover in order to show efficiency of the proposed method, the new approach is compared with some numerical methods.
Institute of Scientific and Technical Information of China (English)
Ting-Hui Ning; Xiao-Yun Jiang
2011-01-01
In this paper,using the fractional Fourier law,we obtain the fractional heat conduction equation with a time-fractional derivative in the spherical coordinate system.The method of variable separation is used to solve the timefractional heat conduction equation.The Caputo fractional derivative of the order 0 ＜ α ≤ 1 is used.The solution is presented in terms of the Mittag-Leffler functions.Numerical results are illustrated graphically for various values of fractional derivative.
Copot, Cosmin; Zhong, Yu; Ionescu, Clara; Keyser, Robin
2013-06-01
In this paper, two methods to tune a fractional-order PI λ D μ controller for a mechatronic system are presented. The first method is based on a genetic algorithm to obtain the parameter values for the fractionalorder PI λ D μ controller by global optimization. The second method used to design the fractional-order PI λ D μ controller relies on an auto-tuning approach by meeting some specifications in the frequency domain. The real-time experiments are conducted using a Steward platform which consists of a table tilted by six servo-motors with a ball on the top of the table. The considered system is a 6 degrees of freedom (d.o.f.) motion platform. The feedback on the position of the ball is obtained from images acquired by a visual sensor mounted above the platform. The fractional-order controllers were implemented and the performances of the steward platform are analyzed.
Directory of Open Access Journals (Sweden)
E. T. Karageorgos
2007-06-01
Full Text Available The PM_{10} mass concentration levels and inorganic chemical composition were determined on 12-h resolution sampling during August 2003 and March 2004, in the centre of Athens, Greece. The August 2003 campaign mean PM_{10} mass concentration, obtained by Beta Attenuation at 5 m above ground in Athinas Street, was 56 μg m^{−3} while the corresponding value for March 2004 was 92 μg m^{−3}. In both campaigns the E.U. imposed daily limit of 50 μg m^{−3} was exceeded on several days. During the March campaign, in Athinas Street, additionally obtained DSFU-PM_{10} (PM_{10-2.5}+PM_{2.5} gravimetric mass concentrations (mean: 121 μg m^{−3} in the "breathing zone", at 1.5 m above ground were significantly higher compared to the respective mean PM_{10} mass concentrations obtained by the same method at 25 m above ground, in a second site (AEDA; mean: 86 μg m^{−3} also in the centre of the city. The above findings suggest that, for a realistic estimation of the exposure of citizens to particulate matter, PM_{10} sampling in the "breathing zone" (1.5–3 m above ground is necessary. Such data are presented for the first time for the centre of Athens. In both campaigns, calcium was found to be the predominant component of the coarse fraction while crust-related aluminosilicates and iron were the other major components. The above elements constitute the most important components of the fine fraction, together with the predominant sulphur. All toxic metals were found in concentrations below the established air quality limits, and most of them in lower concentrations compared to older studies. Lead in particular, appeared mostly in the fine fraction and in very low concentrations compared to studies dating more than a decade back. The predominant ions of the coarse fraction have been found to be Ca^{2+}, NO_{3}^{−}, Na
Directory of Open Access Journals (Sweden)
Jiménez, Álvaro
2011-03-01
Full Text Available The seeds of Sacha inchi (Plukenetia volubilis L. from Colombia were analyzed for their main chemical composition. Sacha inchi seeds (SIS were rich in oil (41.4% and protein (24.7%. The main minerals present in SIS were potassium (5563.5 ppm, magnesium (3210 ppm and calcium (2406 ppm. A fatty acid analysis revealed that a-linolenic (50.8% and linoleic (33.4% acids were the main fatty acids in Sacha inchi oil (SIO. The lipid fractionation of SIO, obtained by solid phase extraction, yielded mainly neutral lipids (97.2%, and lower amounts of free fatty acids (1.2% and phospholipids (0.8%. The physicochemical properties of the oil include: saponification number 185.2; iodine value 193.1; density 0.9187 g/cm3, refractive index 1.4791 and viscosity of 35.4 mPa.s. The melting profiles of SIO were characterized by the presence of one wide endothermic peak with a melting enthalpy of 23.2 J/g. Our results indicate that Sacha inchi is an important new crop with applications in the food and pharmaceutical industries.Semillas de Sacha inchi (Plukenetia volubilis L. de Colombia fueron analizadas en su composición química. Las semillas de Sacha inchi (SIO fueron ricas en aceite (41.4% y proteína (24.7%. Los principales minerales presentes en las SIS fueron potasio (5563.5 ppm, magnesio (3210 ppm y calcio (2406 ppm. El análisis de ácidos grasos reveló que los ácidos a-linolénico (50.8% y linoleico (33.4% fueron los principales ácidos grasos presentes en el aceite de Sacha inchi (SIO. El fraccionamiento del SIO, realizado por extracción en fase sólida, produjo principalmente lípidos neutros (97.2%, y bajas cantidades de ácidos grasos libres (1.2% y fosfolípidos (0.8%. Las propiedades fisicoquímicas del aceite incluyen: índice de saponificación 185.2; índice de yodo 193.1; densidad 0.9187 g/cm3, índice de refracción 1.4791 y viscosidad 35.4 mPa.s. Los perfiles de fusión del SIO se caracterizaron por la presencia de un ancho pico endot
Device for collecting chemical compounds and related methods
Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine
2013-01-01
A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.
The modified simple equation method for solving some fractional-order nonlinear equations
Indian Academy of Sciences (India)
KAPLAN MELIKE; BEKIR AHMET
2016-07-01
Nonlinear fractional differential equations are encountered in various fields of mathematics, physics, chemistry, biology, engineering and in numerous other applications. Exact solutions of these equations play a crucial role in the proper understanding of the qualitative features of many phenomena and processes in various areas of natural science. Thus, many effective and powerful methods have been established and improved. In this study, we establish exact solutions of the time fractional biological population model equation and nonlinearfractional Klein–Gordon equation by using the modified simple equation method.
Directory of Open Access Journals (Sweden)
Petráš Ivo
2011-01-01
Full Text Available This paper deals with the fractional-order linear and nonlinear models used in bioengineering applications and an effective method for their numerical solution. The proposed method is based on the power series expansion of a generating function. Numerical solution is in the form of the difference equation, which can be simply applied in the Matlab/Simulink to simulate the dynamics of system. Several illustrative examples are presented, which can be widely used in bioengineering as well as in the other disciplines, where the fractional calculus is often used.
Legendre Wavelets Method for Solving Fractional Population Growth Model in a Closed System
Directory of Open Access Journals (Sweden)
M. H. Heydari
2013-01-01
Full Text Available A new operational matrix of fractional order integration for Legendre wavelets is derived. Block pulse functions and collocation method are employed to derive a general procedure for forming this matrix. Moreover, a computational method based on wavelet expansion together with this operational matrix is proposed to obtain approximate solution of the fractional population growth model of a species within a closed system. The main characteristic of the new approach is to convert the problem under study to a nonlinear algebraic equation.
Gimbert, Frédéric; Geffard, Alain; Guédron, Stéphane; Dominik, Janusz; Ferrari, Benoit J D
2016-02-01
Along with the growing body of evidence that total internal concentration is not a good indicator of toxicity, the Critical Body Residue (CBR) approach recently evolved into the Tissue Residue Approach (TRA) which considers the biologically active portion of metal that is available to contribute to the toxicity at sites of toxic action. For that purpose, we examined total mercury (Hg) bioaccumulation and subcellular fractionation kinetics in fourth stage larvae of the midge Chironomus riparius during a four-day laboratory exposure to Hg-spiked sediments and water. The debris (including exoskeleton, gut contents and cellular debris), granule and organelle fractions accounted only for about 10% of the Hg taken up, whereas Hg concentrations in the entire cytosolic fraction rapidly increased to approach steady-state. Within this fraction, Hg compartmentalization to metallothionein-like proteins (MTLP) and heat-sensitive proteins (HSP), consisting mostly of enzymes, was assessed in a comparative manner by two methodologies based on heat-treatment and centrifugation (HT&C method) or size exclusion chromatography separation (SECS method). The low Hg recoveries obtained with the HT&C method prevented accurate analysis of the cytosolic Hg fractionation by this approach. According to the SECS methodology, the Hg-bound MTLP fraction increased linearly over the exposure duration and sequestered a third of the Hg flux entering the cytosol. In contrast, the HSP fraction progressively saturated leading to Hg excretion and physiological impairments. This work highlights several methodological and biological aspects to improve our understanding of Hg toxicological bioavailability in aquatic invertebrates. PMID:26688328
Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias
2015-07-01
An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene. PMID:25885756
Directory of Open Access Journals (Sweden)
Mengyue Wang
2012-01-01
Full Text Available Urtica atrichocaulis, an endemic plant to China, is commonly used to treat rheumatoid arthritis even though its pharmaceutical activities and chemical constituents were not studied. Herein, we reported our investigations on the chemical compositions of the phenolic compounds-rich fraction from U. atrichocaulis (TFUA and their antirheumatoid arthritis activities. We found that the TFUA significantly inhibited the adjuvant-induced rats arthritis, carrageenin-induced rats paw edema, cotton pellet-induced mice granuloma, and the acetic acid-induced mice writhing response. Our phytochemical investigations on the TFUA resulted in the first-time isolation and identification of 17 phenolic constituents and a bis (5-formylfurfuryl ether. The extensive HPLC analysis also revealed the chemical compositions of TFUA. Our further biological evaluation of the main phenolic components, individually and collectively, indicated that the antirheumatoid arthritis activities of TFUA were the combined effect of multiple phenolic constituents.
Chemical constituents in n-butanol fractions of Costus afer ker Gawl leaf and stem
Directory of Open Access Journals (Sweden)
Godswill Nduka Anyasor
2014-04-01
Conclusion: The bioactive compounds identified in the n-butanol fractions of C. afer leaves and stem may explain the folkloric use of C. afer plant in the treatment of chronic inflammatory and oxidative stress related diseases. [J Intercult Ethnopharmacol 2014; 3(2.000: 78-84
International Nuclear Information System (INIS)
Highlights: • A stationary transport equation has been solved using the technique of Haar wavelet collocation method. • This paper intends to provide the great utility of Haar wavelets to nuclear science problem. • In the present paper, two-dimensional Haar wavelets are applied. • The proposed method is mathematically very simple, easy and fast. - Abstract: In this paper the numerical solution for the fractional order stationary neutron transport equation is presented using Haar wavelet Collocation Method (HWCM). Haar wavelet collocation method is efficient and powerful in solving wide class of linear and nonlinear differential equations. This paper intends to provide an application of Haar wavelets to nuclear science problems. This paper describes the application of Haar wavelets for the numerical solution of fractional order stationary neutron transport equation in homogeneous medium with isotropic scattering. The proposed method is mathematically very simple, easy and fast. To demonstrate about the efficiency and applicability of the method, two test problems are discussed
Energy Technology Data Exchange (ETDEWEB)
Saha Ray, S., E-mail: santanusaharay@yahoo.com; Patra, A.
2014-10-15
Highlights: • A stationary transport equation has been solved using the technique of Haar wavelet collocation method. • This paper intends to provide the great utility of Haar wavelets to nuclear science problem. • In the present paper, two-dimensional Haar wavelets are applied. • The proposed method is mathematically very simple, easy and fast. - Abstract: In this paper the numerical solution for the fractional order stationary neutron transport equation is presented using Haar wavelet Collocation Method (HWCM). Haar wavelet collocation method is efficient and powerful in solving wide class of linear and nonlinear differential equations. This paper intends to provide an application of Haar wavelets to nuclear science problems. This paper describes the application of Haar wavelets for the numerical solution of fractional order stationary neutron transport equation in homogeneous medium with isotropic scattering. The proposed method is mathematically very simple, easy and fast. To demonstrate about the efficiency and applicability of the method, two test problems are discussed.
Fourier spectral methods for fractional-in-space reaction-diffusion equations
Bueno-Orovio, Alfonso
2014-04-01
© 2014, Springer Science+Business Media Dordrecht. Fractional differential equations are becoming increasingly used as a powerful modelling approach for understanding the many aspects of nonlocality and spatial heterogeneity. However, the numerical approximation of these models is demanding and imposes a number of computational constraints. In this paper, we introduce Fourier spectral methods as an attractive and easy-to-code alternative for the integration of fractional-in-space reaction-diffusion equations described by the fractional Laplacian in bounded rectangular domains of ℝ. The main advantages of the proposed schemes is that they yield a fully diagonal representation of the fractional operator, with increased accuracy and efficiency when compared to low-order counterparts, and a completely straightforward extension to two and three spatial dimensions. Our approach is illustrated by solving several problems of practical interest, including the fractional Allen–Cahn, FitzHugh–Nagumo and Gray–Scott models, together with an analysis of the properties of these systems in terms of the fractional power of the underlying Laplacian operator.
Strang-type preconditioners for solving fractional diffusion equations by boundary value methods
Gu, Xian-Ming; Huang, Ting-Zhu; Zhao, Xi-Le; Li, Hou-Biao; Li, Liang
2013-01-01
The finite difference scheme with the shifted Gr\\"{u}nwarld formula is employed to semi-discrete the fractional diffusion equations. This spatial discretization can reduce to the large system of ordinary differential equations (ODEs) with initial values. Recently, boundary value method (BVM) was developed as a popular algorithm for solving large systems of ODEs. This method requires the solutions of one or more nonsymmetric, large and sparse linear systems. In this paper, the GMRES method wit...
Preparative free-flow electrophoresis as a method of fractionation of natural organic materials
Leenheer, J.A.; Malcolm, R.L.
1973-01-01
Preparative free-flow electrophoresis was found to be an efficient method of conducting large-scale fractionations of the natural organic polyelectrolytes occurring in many surface waters and soils. The method of free-flow electrophoresis obviates, the problem of adsorption upon a supporting medium and permits the use of high potential gradients and currents because of an efficient cooling system. Separations were monitored by determining organic carbon concentration with a dissolved carbon analyzer, and color was measured by absorbance at 400 nanometers. Organic materials from waters and soils were purified by filtration, hydrogen exchange, and dialysis and were concentrated by freeze drying or freeze concentration. In electrophoretic fractionations of natural organic materials typically found in surface waters and soils, color was found to increase with the charge of the fraction.
Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias
2015-12-01
Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 μg/L for nitrated and from 0.1 to 6.6 μg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 μg/L for nitrated and 0.3-8.9 μg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected. PMID:26446274
Fractionation of sheep cheese whey by a scalable method to sequentially isolate bioactive proteins.
Pilbrow, Jodi; Bekhit, Alaa El-din A; Carne, Alan
2016-07-15
This study reports a procedure for the simultaneous purification of glyco(caseino)macropeptide, immunoglobulin, lactoperoxidase, lactoferrin, α-lactalbumin and β-lactoglobulin from sheep cheese sweet whey, an under-utilized by-product of cheese manufacture generated by an emerging sheep dairy industry in New Zealand. These proteins have recognized value in the nutrition, biomedical and health-promoting supplements industries. A sequential fractionation procedure using economical anion and cation exchange chromatography on HiTrap resins was evaluated. The whey protein fractionation is performed under mild conditions, requires only the adjustment of pH between ion exchange chromatography steps, does not require buffer exchange and uses minimal amounts of chemicals. The purity of the whey protein fractions generated were analyzed by reversed phase-high performance liquid chromatography and the identity of the proteins was confirmed by mass spectrometry. This scalable procedure demonstrates that several proteins of recognized value can be fractionated in reasonable yield and purity from sheep cheese whey in one streamlined process. PMID:26948602
International Nuclear Information System (INIS)
Proton magnetic resonance has been used to monitor the microscopic physical properties of etiolated hypocotyl cell walls from Phaseolus vulgaris L. at all stages in a series of chemical fractionations with ammonium oxalate and potassium hydroxide. Solid echo measurements indicate that 75% of the polymers in the intact cell wall, including the cellulose and most of the hemicelluloses, are arranged such that there is almost complete restraint of molecular motion. The chemical fractionations generally altered the physical structures of the remaining cell wall components. Digestion with 0.25% ammonium oxalate/oxalic acid solubilized the pectin and increased the mobility of the hemicellulose I component. Extraction with 4% potassium hydroxide removed the hemicellulose I component and loosened the hemicellulose II. Further extraction with 24% potassium hydroxide removed the hemicellulose II and loosened some of the cellulose. The cellulose crystallinity, as monitored by Jeener echo measurements decreased from 83% to 63% during these fractionations. We conclude that, while hemicellulose I is firmly attached to hemicellulose II, it is not in a closely packed structure. Hemicellulose II is strongly bound to cellulose and has a much more closely packed structure
Application of X-ray fluorescence method for elemental analysis of PM2.5 fraction
Directory of Open Access Journals (Sweden)
Samek Lucyna
2015-09-01
Full Text Available The scientific interest in air pollution comes from its influence on human health, the condition of cultural heritage and climate. The PM2.5 fraction (particles of a diameter of 2.5 mm or below, indirectly, has a significant impact on health which is associated with respiratory tract and blood vessel related diseases. However, not only the size, but also the content of the particles has a significant meaning. To determine the particulate matter contents, elemental analysis can be performed using numerous techniques, the most important of which is X-ray fluorescence. In this study, samples of PM2.5 fraction collected in Krakow, Poland were analyzed. The X-ray fluorescence method was used to perform elemental analysis. The gravimetric method was applied to determine the concentration of the PM2.5 fraction. Low detection limits of individual elements and precision of the X-ray fluorescence method were determined. The concentrations of the following elements: Cl, K, Ca, Cr, Mn, Fe, Cu, Zn, Br, Rb, Sr and Pb in the PM2.5 fraction samples collected in Krakow were evaluated. The homogeneity of the samples was also estimated. The concentrations of PM2.5 fraction collected in the summer of 2013 were in the range of 6-23 ng/m3. The concentrations of PM2.5 fraction collected in the winter of 2013 were in the range of 26-171 ng/m3. The precision of the method was found to be below 1% for elements with high concentration in the sample and 6-8 % for trace elements.
Antimutagenic activity of major fractions of Zataria multiflora Boiss by Ames method
Directory of Open Access Journals (Sweden)
Fariba Sharififar
2015-01-01
Full Text Available Zataria multiflora is a medicinal plant that has been interested in antimutagenicity effect because of its high antioxidant activity and richness of flavonoids. Antimutagenicity effect of total extract of the plant has been reported previously. Aerial parts of Z. multiflora were extracted by petroleum ether, chloroform and 80% methanol by liquid-liquid extraction method consequently. The fractions were concentrated in vacuum and dried at 40°C in oven. The genotype of two standard strains of Salmonella typhimurium (TA98, TA100 was confirmed by the evaluation of two important factors of histidine requirement and the presence of R factor. The minimum inhibition concentration (MIC of the fractions against these two strains was determined by agar dilution method. From each fraction, various concentrations less than MIC were studied for anti-mutagenic test. The sample along with bacterial strain and mutagen agent were incubated at 37°C for 48 h. The number of revertant colonies was counted and compared with control plates. Our results showed that all fractions especially petroleum ether and chloroform ones maintain the number of colonies in the standard range in control plates and prevent from the growth of many strains of bacteria and increase of revertant colonies enhancement in a concentration-dependent manner. This effect was prominent against TA100 starin. Methanolic fraction exhibited anti-mutagen activity just in the highest used concentration in the presence of TA98.
[Effect of Nano Zeolite on Chemical Fractions of Cd in Soil and Its Uptake by Cabbage].
Xiong, Shi-juan; Xu, Wei-hong; Xie, Wen-wen; Chen, Rong; Chen, Yong-qin; Chi, Sun-lin; Chen, Xu- gen; Zhang, Jin-zhong; Xiong, Zhi-ting; Wang, Zheng-yin; Xie, De-ti
2015-12-01
Incubation experiments were carried out to investigate the influence of different nano zeolite (NZ) and ordinary zeolite (OZ) levels(0, 5, 10 and 20 g · kg⁻¹) on the change trends in fraction distribution coefficient (FDC) of Cd when exposed to different Cadmium (Cd) levels (1, 5, 10 and 15 mg · kg⁻¹), and pot experiments were carried out to investigate their influence on soil Cd fraction and Cd uptake by cabbage. The results in incubation experiments showed that the application of nano zeolite as well as ordinary zeolite effectively decreased the FDC of exchangeable Cd and increased the FDC of Fe-Mn oxide fraction. The FDC of soil Cd from 0 d to 28 d was deceased at first, then increased and tended to be stable, and finally increased. At the end of incubation, the FDC of soil exchangeable Cd decreased from 72.0%-88.0% to 30.0%-66.4%. Exchangeable fraction Cd was the most dominant Cd fraction in soil during the whole incubation. The results in pot experiment indicated that the application of nano zeolite and ordinary zeolite decreased the concentration and FDC of soil exchangeable Cd, and concurrently the concentration and FDC of Cd in carbonate, Fe-Mn oxide, organic matter and residual fraction were increased. The lowest EX-Cd was observed in the treatment with high dose of nano zeolite (20 g · kg⁻¹). The FDC of exchangeable Cd showed significant negative relationship with the soil pH (P < 0.05), and was concurrently extremely positively correlated with Cd concentration in shoot and root of cabbage (P < 0.01). Soil pH increased by 1.8%-45.5% and 6.1%-54.3% in the presence of zeolite when exposed to 5 mg · kg⁻¹ 1 and Cd, respectively; FDC of exchangeable Cd decreased by 16.3%-47.7% and 16.2%-46.7%; Cd concentration in each tissues of cabbage decreased by 1.0%-75.0% and 3.8%-53.2%, respectively. Moreover, the reduction effect of nano zeolite on soil and plant Cd was better than that of ordinary zeolite. The growth of cabbage was stimulated by low and
Simplifying Chemical Reactor Design by using Molar Quantities Instead of Fractional Conversion.
Brown, Lee F.; Falconer, John L.
1987-01-01
Explains the advantages of using molar quantities in chemical reactor design. Advocates the use of differential versions of reactor mass balances rather than the integrated forms. Provides specific examples and cases to illustrate the principles. (ML)
Vaz, Josiana A.; Tavares, Catarina; Almeida, Gabriela M.; Martins, Anabela; Vasconcelos, M. Helena; Ferreira, Isabel C. F. R.
2012-01-01
Mushrooms have become attractive as functional foods and as a source of physiologically beneficial bioactive compounds. The huge mushrooms reservoir of Northeast Portugal must be chemically and nutritionally characterized for the benefit of the local populations and for the genetic conservation of wild macrofungi. Herein, we describe and compare the chemical constituents (phenolic compounds, macronutrients, sugars, fatty acids, tocopherols and ascorbic acid) of four wild edible mushrooms wide...
Xiang, Yuling; Xu, Xiangqun; Li, Juan
2012-10-15
The medicinal mushroom Inonotus obliquus has been a folk remedy for a long time in East-European and Asian countries. We first reported the enhancement in production and antioxidant activity of exopolysaccharides by I. obliquus culture under lignocellulose decomposition. In this study, the two different sources of exopolysaccharides from the control medium and the lignocellulose (corn stover) containing medium by I. obliquus in submerged fermentation were fractionated and purified by chromatography. The exopolysaccharides from the corn stover-containing medium presented significantly stronger hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity than the control. Three fractions from the control medium and the corn stover-containing medium were isolated respectively. The fraction of DEPL3 from the corn stover-containing medium with the highest protein content (38.3%), mannose content (49.6%), and the lowest molecular weight (29 kDa) had the highest antioxidant activity with the lowest IC50 values. In conclusion, lignocellulose decomposition changed the chemical characterisation and significantly enhanced the antioxidant activity of exopolysaccharide fractions. PMID:23442636
Chemical Analysis Methods for Silicon Carbide
Institute of Scientific and Technical Information of China (English)
Shen Keyin
2006-01-01
@@ 1 General and Scope This Standard specifies the determination method of silicon dioxide, free silicon, free carbon, total carbon, silicon carbide, ferric sesquioxide in silicon carbide abrasive material.
Homotopy Analysis Method for Time-Fractional Schrödinger Equations
Directory of Open Access Journals (Sweden)
Nauman ASGHAR
2012-12-01
Full Text Available The Homotopy Analysis Method (HAM is applied to tackle time-fractional Schrödinger equations. The proposed technique is fully compatible with the complexity of these problems and obtained results are highly encouraging. Numerical results coupled with graphical representations explicitly reveal the complete reliability and efficiency of the suggested algorithm.
Strang-type preconditioners for solving fractional diffusion equations by boundary value methods
Gu, Xian-Ming; Huang, Ting-Zhu; Zhao, Xi-Le; Li, Hou-Biao; Li, Liang
2015-01-01
The finite difference scheme with the shifted Grünwarld formula is employed to semi-discrete the fractional diffusion equations. This spatial discretization can reduce to the large system of ordinary differential equations (ODEs) with initial values. Recently, boundary value method (BVM) was develop
DEFF Research Database (Denmark)
de Tomás, Alberto; Nieto, Héctor; Guzinski, Radoslaw;
2014-01-01
Remote sensing has proved to be a consistent tool for monitoring water fluxes at regional scales. The triangle method, in particular, estimates the evaporative fraction (EF), defined as the ratio of latent heat flux (LE) to available energy, based on the relationship between satellite observations...
International Nuclear Information System (INIS)
Chemical characteristics of High oleic acid fraction (HOF) of Moringa oleifera oil (MOO) was compared with sunflower, soybean and canola oils. HOF of MOO was obtained by dry fractionation at 0 degree C. Iodine value and C18:1 in HOF increased from 61.55 to 82.47 points and 70.29% to 81.15%, respectively. Cloud point of HOF was 1.1 degree C as compared to 10.2 degree C in MOO. The induction period of HOF was greater than all the vegetable oils tested in this investigation. HOF can be used as a source of edible oil with better health attributes and superior storage stability. (author)
The Galerkin finite element method for a multi-term time-fractional diffusion equation
Jin, Bangti
2015-01-01
© 2014 The Authors. We consider the initial/boundary value problem for a diffusion equation involving multiple time-fractional derivatives on a bounded convex polyhedral domain. We analyze a space semidiscrete scheme based on the standard Galerkin finite element method using continuous piecewise linear functions. Nearly optimal error estimates for both cases of initial data and inhomogeneous term are derived, which cover both smooth and nonsmooth data. Further we develop a fully discrete scheme based on a finite difference discretization of the time-fractional derivatives, and discuss its stability and error estimate. Extensive numerical experiments for one- and two-dimensional problems confirm the theoretical convergence rates.
Energy Technology Data Exchange (ETDEWEB)
Sluiter, Amie; Sluiter, Justin; Wolfrum, Ed; Reed, Michelle; Ness, Ryan; Scarlata, Christopher; Henry, Jeanette
2016-08-01
Accurate and precise chemical characterization of biomass feedstocks and process intermediates is a requirement for successful technical and economic evaluation of biofuel conversion technologies. The uncertainty in primary measurements of the fraction insoluble solid (FIS) content of dilute acid pretreated corn stover slurry is the major contributor to uncertainty in yield calculations for enzymatic hydrolysis of cellulose to glucose. This uncertainty is propagated through process models and impacts modeled fuel costs. The challenge in measuring FIS is obtaining an accurate measurement of insoluble matter in the pretreated materials, while appropriately accounting for all biomass derived components. Three methods were tested to improve this measurement. One used physical separation of liquid and solid phases, and two utilized direct determination of dry matter content in two fractions. We offer a comparison of drying methods. Our results show utilizing a microwave dryer to directly determine dry matter content is the optimal method for determining FIS, based on the low time requirements and the method optimization done using model slurries.
Çekiç, Sema Demirci; Demir, Aslı; Başkan, Kevser Sözgen; Tütem, Esma; Apak, Reşat
2015-05-01
Most milk-applied antioxidant assays in literature are based on the isolation and quantification of individual antioxidative compounds, whereas total antioxidant capacity (TAC) gives a more holistic picture due to cooperative action of antioxidants. Recently, the cupric reducing antioxidant capacity (CUPRAC) method has been modified to measure the antioxidant capacities of thiol-containing proteins, where the classical ammonium acetate buffer - that may otherwise precipitate proteins- was replaced with concentrated urea buffer (able to expose embedded thiol groups of proteins to oxidative attack) adjusted to pH 7.0. Thus, antioxidant capacity of milk was investigated with two competing TAC assays, namely CUPRAC and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulphonic acid))/persulphate, because only these assays were capable of evaluating protein contribution to the observed TAC value. As milk fat caused turbidity, experiments were carried out with skim milk or defatted milk samples. To determine TAC, modified CUPRAC method was applied to whole milk, separated and redissolved protein fractions, and the remaining liquid phase after necessary operations. Both TAC methods were investigated for their dilution sensitivity and antioxidant power assessment of separate milk fractions such as casein and whey. Proteins like β-lactoglobulin and casein (but not simple thiols) exhibited enhanced CUPRAC reactivity with surfactant (SDS) addition. Addition of milk protein fractions to whole skim milk produced significant 'negative-biased' deviations (up to -26% relative standard error) from TAC absorbance additivity in the application of the ABTS method, as opposed to that of the CUPRAC method less affected by chemical deviations from Beer's law thereby producing much smaller deviations from additivity (i.e. the property of additivity is valid when the measured TAC of a mixture is equal to the sum of individual antioxidant capacities of its constituents). PMID:25731579
Joo, H
1999-01-01
Recent test results indicated drawbacks associated with the simple exponential attenuation method (SEAM) as currently applied to neutron radiography measurements to determine vapor fractions in a hydrogenous two-phase flow in a metallic conduit. The scattering component of the neutron beam intensity exiting the flow system is not adequately accounted for by SEAM, and this leads to inaccurate results. To properly account for the scattering effect, a neutron scattering probability method (SPM) is developed. The method applies a neutron-hydrogen scattering kernel to scattered thermal neutrons that leave the incident beam in narrow conduits but eventually show up elsewhere in the measurements. The SPM has been tested with known vapor (void) distributions within an acrylic disk and a water/vapor channel. The vapor (void) fractions deduced by SPM are in good agreement with the known exact values. Details of the scattering correction method and the test results are discussed.
Monotone method for Riemann-Liouville multi-order fractional differential systems
Directory of Open Access Journals (Sweden)
Zachary Denton
2016-01-01
Full Text Available In this paper we develop the monotone method for nonlinear multi-order \\(N\\-systems of Riemann-Liouville fractional differential equations. That is, a hybrid system of nonlinear equations of orders \\(q_i\\ where \\(0 \\lt q_i \\lt 1\\. In the development of this method we recall any needed existence results along with any necessary changes. Through the method's development we construct a generalized multi-order Mittag-Leffler function that fulfills exponential-like properties for multi-order systems. Further we prove a comparison result paramount for the discussion of fractional multi-order inequalities that utilizes lower and upper solutions of the system. The monotone method is then developed via the construction of sequences of linear systems based on the upper and lower solutions, and are used to approximate the solution of the original nonlinear multi-order system.
Dietary fibre fractions in cereal foods measured by a new integrated AOAC method.
Hollmann, Juergen; Themeier, Heinz; Neese, Ursula; Lindhauer, Meinolf G
2013-10-01
The reliable determination of soluble, insoluble and total dietary fibre in baked goods and cereal flours is an important issue for research, nutritional labelling and marketing. We compared total dietary fibre (TDF) contents of selected cereal based foods determined by AOAC Method 991.43 and the new AOAC Method 2009.01. Fifteen bread and bakery products were included in the study. Our results showed that TDF values of cereal products determined by AOAC Method 2009.01 were always significantly higher than those determined by AOAC Method 991.43. This was explained by the inclusion of low molecular weight soluble fibre fractions and resistant starch fractions in the TDF measurement by AOAC 2009.01. This documents that nutritional labelling of cereal products poses the challenge how to update TDF data in nutrient databases in a reasonable time with an acceptable expenditure. PMID:23601411
Korang-Yeboah, Maxwell; Akhtar, Sohail; Siddiqui, Akhtar; Rahman, Ziyaur; Khan, Mansoor A
2016-01-01
Monitoring of the physical state of warfarin sodium (WS) in products is essential for minimizing product quality variability in order to ensure consistent clinical performance. This study reports the development of chemometric models for quantifying the crystalline and amorphous fractions of WS in commercial drug products using NIR spectroscopy. Formulations based on commercially available products with different API to excipient ratio were used for the study. For each content, two formulations containing either lactose monohydrate or lactose anhydrous as the predominant formulation excipient were prepared. Two formulations containing either 100% amorphous WS (AWS) or crystalline WS (CWS) were prepared and mixed in various ratios to obtain sample matrices containing AWS/CWS 0-100%. The uniformity of the samples was confirmed by near infrared chemical imaging. Data were mathematically pretreated by multiplicative signal correction and Savitzky-Golay second derivative. Principal component regression and partial least square regression models were developed from mathematically treated data. All the models showed linear trend for amorphous and crystalline fractions of the WS as indicated by correlation and R(2) > 0.99 and >0.98, respectively. The models demonstrated good performance parameters with a low-root mean squared error, standard error and bias. The model predicted CWS and AWS contents were in very close agreement with the actual values. The study indicated the utility of NIR chemometric methods in quantification of the crystalline and/or amorphous fraction of WS in its products. PMID:26161939
A new MC-based method to evaluate the fission fraction uncertainty at reactor neutrino experiment
Ma, X B; Chen, Y X
2016-01-01
Uncertainties of fission fraction is an important uncertainty source for the antineutrino flux prediction in a reactor antineutrino experiment. A new MC-based method of evaluating the covariance coefficients between isotopes was proposed. It was found that the covariance coefficients will varying with reactor burnup and which may change from positive to negative because of fissioning balance effect, for example, the covariance coefficient between $^{235}$U and $^{239}$Pu changes from 0.15 to -0.13. Using the equation between fission fraction and atomic density, the consistent of uncertainty of fission fraction and the covariance matrix were obtained. The antineutrino flux uncertainty is 0.55\\% which does not vary with reactor burnup, and the new value is about 8.3\\% smaller.
García-Gutiérrez Baez, Carlos; Martin Martin, Miguel Angel; Muñoz Ortega, Francisco Javier; Reyes Castro, Miguel E.; Taguas Coejo, Francisco Javier
2014-01-01
The study of granular systems is of great interest to many fields of science and technology. The packing of particles affects to the physical properties of the granular system. In particular, the crucial influence of particle size distribution (PSD) on the random packing structure increase the interest in relating both, either theoretically or by computational methods. A packing computational method is developed in order to estimate the void fraction corresponding to a fractal-like particle s...
An Implicit Numerical Method for Semilinear Space-Time Fractional Diffusion Equation
Directory of Open Access Journals (Sweden)
Gunvant Achutrao BIRAJDAR
2015-11-01
Full Text Available The aim of the study is to obtain the solution of semilinear space-time fractional diffusion equation for the first initial boundary value problem (IBVP, by applying an implicit method. The main idea of the method is to convert the problem into an algebraic system which simplifies the computations. We discuss the stability, convergence and error analysis of the implicit finite difference scheme with suitable example using MATLAB.
Directory of Open Access Journals (Sweden)
Syed Tauseef Mohyud-Din
2015-01-01
Full Text Available This paper witnesses the coupling of an analytical series expansion method which is called reduced differential transform with fractional complex transform. The proposed technique is applied on three mathematical models, namely, fractional Kaup-Kupershmidt equation, generalized fractional Drinfeld-Sokolov equations, and system of coupled fractional Sine-Gordon equations subject to the appropriate initial conditions which arise frequently in mathematical physics. The derivatives are defined in Jumarie’s sense. The accuracy, efficiency, and convergence of the proposed technique are demonstrated through the numerical examples. It is observed that the presented coupling is an alternative approach to overcome the demerit of complex calculation of fractional differential equations. The proposed technique is independent of complexities arising in the calculation of Lagrange multipliers, Adomian’s polynomials, linearization, discretization, perturbation, and unrealistic assumptions and hence gives the solution in the form of convergent power series with elegantly computed components. All the examples show that the proposed combination is a powerful mathematical tool to solve other nonlinear equations also.
Institute of Scientific and Technical Information of China (English)
Mohammad Amzad Hossain; Seham Salim Al-Hdhrami; Afaf Mohammed Weli; Qasim Al-Riyami; Jamal Nasser Al-Sabahi
2014-01-01
Objective: To analyze and identify the chemical compositions of different organic plants crude extracts of Mentha piperita (M. piperita) grown in Sultanate of Oman by gas chromatography-mass spectrometry (GC-MS). Methods: The powder sample was extracted with methanol by using Soxhlet extractor. Methanol crude extracts of M. piperita and its derived fractions of hexane, chloroform, ethyl acetate and butanol were prepared.Results:MS showed that majority of these compounds are bioactive.Conclusions:According to the results of the present study, the plant crude extracts could be Qualitative analyses of various organic plant crude extracts of M. piperita by using GC-used as medicine for the treatment of different diseases. The analysis and identification of the chemical compounds in the plant crude extracts by using GC-MS was the first time.
Jiménez, Álvaro; Rosada, Lina María; Gutiérrez, Luis Felipe
2011-01-01
The seeds of Sacha inchi (Plukenetia volubilis L.) from Colombia were analyzed for their main chemical composition. Sacha inchi seeds (SIS) were rich in oil (41.4%) and protein (24.7%). The main minerals present in SIS were potassium (5563.5 ppm), magnesium (3210 ppm) and calcium (2406 ppm). A fatty acid analysis revealed that a-linolenic (50.8%) and linoleic (33.4%) acids were the main fatty acids in Sacha inchi oil (SIO). The lipid fractionation of SIO, obtained by solid phase extraction, y...
DEFF Research Database (Denmark)
Guillaumie, Fanny; Justesen, Sune F. L.; Mutenda, Kudzai E.;
2006-01-01
were produced in excellent purity (>95%). Elution of OGAs followed by direct analysis of the peak fractions by MALDI-TOF MS. Purified OGAs (DP 5-7) were chemoselectively immobilized onto aminooxy-terminated polyethylene glycol polyacrylamide (PEGA) supports. Solid-phase anchoring took place at the...... 40 or 60 degrees C, and the chemical degradation products released from the support were analyzed by ESIMS. In all cases, the original OGA was degraded into smaller oligomers of various sizes down to the monomer. This work illustrates some of the basic principles underlying a strategy ultimately...
DEFF Research Database (Denmark)
Guillaumie, Fanny; Justesen, Sune Frederik Lamdahl; Mutenda, K.E.;
2006-01-01
were produced in excellent purity (> 95%). Elution of OGAs followed by direct analysis of the peak fractions by MALDI-TOF MS. Purified OGAs (DP 5-7) were chemoselectively immobilized onto aminooxy-terminated polyethylene glycol polyacrylamide (PEGA) supports. Solid-phase anchoring took place at the...... 40 or 60 degrees C, and the chemical degradation products released from the support were analyzed by ESIMS. In all cases, the original OGA was degraded into smaller oligomers of various sizes down to the monomer. This work illustrates some of the basic principles underlying a strategy ultimately...
Chemical form analysis method of particulate nickel compounds
International Nuclear Information System (INIS)
Chemical form of nickel is metallic nickel, nickel oxide and nickel ferrite in the PWR primary chemistry condition. The distribution of chemical form depends on Ni/Fe ratio and chemistry condition, especially dissolved hydrogen concentration. Nickel is parent element of Co-58 and the chemical form is important for Co-58 generation. A method of chemical form analysis of nickel has been developed. This method uses the difference in dissolution characteristics of nickel compounds. Metallic nickel and others are separated by nitric acid, and others are divided to nickel oxide and nickel ferrite by oxalic acid. Some cruds in the primary coolant of a PWR were analyzed by using this method. The method is not complex and available at chemical laboratory in a nuclear power plant. (author)
Chemical decontamination method for radioactive metal waste
International Nuclear Information System (INIS)
When contaminants mainly composed of copper remained on the surface of stainless steel wastes sent from an electrolytic reduction as a first step are chemically decontaminated, metal wastes are discriminated to carbon steel wastes and stainless steel wastes. Then, the carbon steel wastes are applied only with the first step of immersing in a sulfuric acid solution, and stainless steel wastes are applied with a first step of immersing into a sulfuric acid solution for electrolytic reduction for a predetermined period of time and a second step of immersing into a liquid in which an oxidative metal salt is added to sulfuric acid. The decontamination liquid which is used for immersing the stainless steel wastes in the second step and the oxidation force of which is lowered is used as the sulfuric acid solution in the first step for the carbon steel wastes. In view of the above, the decontamination liquid of the second step can be utilized most effectively, enabling to greatly decrease the secondary wastes and to improve decontamination efficiency. (T.M.)
A chemical method for estimating methanogenic biomass
Smith, G. C.; Floodgate, G. D.
1992-10-01
Methane-forming bacteria belong to the archaebacterial kingdom and as such possess unique membrane lipids in that phytanyl ether linked phospholipids replace the more usual ester linked analogues. A common methanogenic membrane ether lipid (Di-Phytanyl Glycerol Ether; DPGE) can be extracted using solvents, chemically broken down, derivatized, purified using thin layer chromatography, and finally analysed quantitatively by capillary gas chromatography. In order to evaluate the concentration of DPGE as a means of estimating the biomass of methanogens, this membrane lipid was compared with cell numbers, methane production and turbidity at 578 nm in a controlled growth experiment of a marine methanogenic monoculture of Methanolobus tindarius. It was found that the DPGE lipid data produced similar growth curves to the other measured parameters. All the parameters used to monitor the growth experiment showed an interesting change at a point in the growth cycle of M. tindarius where cell division slowed down and the growth of individual cells appeared to be the major mechanism of increasing the biomass. Preliminary environmental samples taken from both a marine inter-tidal and a freshwater site were analysed for the DPGE lipid and the results are discussed.
Different methods evaluation of antioxidant properties of Myrtus communis extract and its fractions
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Soheila Moein
2015-09-01
Full Text Available Myrtus communis L. is a plant traditionally used as an antiseptic and disinfectant drug. In this research, the antioxidant activity of Myrtus communis was assayed by evaluating radical scavenging activity, reducing power, FRAP method and determination of phenolic compounds. The methanolic extract of leaves of Myrtus communis was fractionated by using petroleum ether, chloroform, ethyl acetate and buthanol. In reducing power, different concentrations of samples were mixed with phosphate buffer, ferrocyanate, TCA and ferric chloride. Different concentrations of samples were mixed with DPPH and after 30 min the absorbances were measured. For determination of phenolic content, 500 μl of sample was mixed with Folin-Ciocalteu and sodium carbonate. For determination of flavonoids, 500 μl of sample was mixed with 2 ml of distilled water, NaNO2 and NaOH. In reducing power method, chloroform fraction showed the highest reducing capacity. In the DPPH radical scavenging method, the highest antioxidant capacity was found in buthanol fraction (IC50=84.42±1.8 μg/ml. In FRAP method, the highest antioxidant capacity was found in crude extract (5.4±0.3 mg/ml and buthanol fractions (5.51±0.4 mg/ml, respectively. The highest amount of phenolic compounds was detected in ethyl acetate fraction of Myrtus communis (17.5±0.001 μg/g. The highest amount of flavonoids was found in crude extract of Myrtus communis (171.9±7.3 μg/ml. Overall, we can suggest that the leaves of Myrtus communis can be used as antioxidant and as a food additives to avoid oxidative degradation of foods.
Preconditioned iterative methods for space-time fractional advection-diffusion equations
Zhao, Zhi; Jin, Xiao-Qing; Lin, Matthew M.
2016-08-01
In this paper, we propose practical numerical methods for solving a class of initial-boundary value problems of space-time fractional advection-diffusion equations. First, we propose an implicit method based on two-sided Grünwald formulae and discuss its stability and consistency. Then, we develop the preconditioned generalized minimal residual (preconditioned GMRES) method and preconditioned conjugate gradient normal residual (preconditioned CGNR) method with easily constructed preconditioners. Importantly, because resulting systems are Toeplitz-like, fast Fourier transform can be applied to significantly reduce the computational cost. We perform numerical experiments to demonstrate the efficiency of our preconditioners, even in cases with variable coefficients.
Tahiri, Abdelghani; Richel, Aurore; Destain, Jacqueline; Druart, Philippe; Thonart, Philippe; Ongena, Marc
2016-03-01
Humic substances (HS) are complex and heterogeneous mixtures of organic compounds that occur everywhere in the environment. They represent most of the dissolved organic matter in soils, sediments (fossil), water, and landfills. The exact structure of HS macromolecules has not yet been determined because of their complexity and heterogeneity. Various descriptions of HS are used depending on specific environments of origin and research interests. In order to improve the understanding of the structure of HS extracted from landfill leachate (LHS) and commercial HS from leonardite (HHS), this study sought to compare the composition and characterization of the structure of LHS and HHS using elemental composition, chromatographic (high-performance liquid chromatography (HPLC)), and spectroscopic techniques (UV-vis, FTIR, NMR, and MALDI-TOF). The results showed that LHS molecules have a lower molecular weight and less aromatic structure than HHS molecules. The characteristics of functional groups of both LHS and HHS, however, were basically similar, but there was some differences in absorbance intensity. There were also less aliphatic and acidic functional groups and more aromatic and polyphenolic compounds in the humic acid (HA) fraction than in the fulvic acid (FA) and other molecules (OM) fractions of both origins. The differences between LHS and HHS might be due to the time course of humification. Combining the results obtained from these analytical techniques cold improve our understanding of the structure of HS of different origins and thus enhance their potential use. PMID:26781101
Error Analysis of a Finite Element Method for the Space-Fractional Parabolic Equation
Jin, Bangti
2014-01-01
© 2014 Society for Industrial and Applied Mathematics We consider an initial boundary value problem for a one-dimensional fractional-order parabolic equation with a space fractional derivative of Riemann-Liouville type and order α ∈ (1, 2). We study a spatial semidiscrete scheme using the standard Galerkin finite element method with piecewise linear finite elements, as well as fully discrete schemes based on the backward Euler method and the Crank-Nicolson method. Error estimates in the L2(D)- and Hα/2 (D)-norm are derived for the semidiscrete scheme and in the L2(D)-norm for the fully discrete schemes. These estimates cover both smooth and nonsmooth initial data and are expressed directly in terms of the smoothness of the initial data. Extensive numerical results are presented to illustrate the theoretical results.
Modified Step Variational Iteration Method for Solving Fractional Biochemical Reaction Model
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R. Yulita Molliq
2011-01-01
Full Text Available A new method called the modification of step variational iteration method (MoSVIM is introduced and used to solve the fractional biochemical reaction model. The MoSVIM uses general Lagrange multipliers for construction of the correction functional for the problems, and it runs by step approach, which is to divide the interval into subintervals with time step, and the solutions are obtained at each subinterval as well adopting a nonzero auxiliary parameter ℏ to control the convergence region of series' solutions. The MoSVIM yields an analytical solution of a rapidly convergent infinite power series with easily computable terms and produces a good approximate solution on enlarged intervals for solving the fractional biochemical reaction model. The accuracy of the results obtained is in a excellent agreement with the Adam Bashforth Moulton method (ABMM.
Directory of Open Access Journals (Sweden)
Jean Sérgio Rosset
2014-10-01
Full Text Available Mechanized harvesting maintenance of trash from cane sugar and soil application of waste as vinasse and filter cake can improve the system of crop yield. Thus, this study aimed to evaluate the changes in the chemical, the stock of total organic carbon and humified organic matter fractions in an Oxisol cultivated with cane sugar with the following management systems: with sugarcane vinasse application (CCV, without application of burnt cane waste (CQS, with burnt cane vinasse application (CQV, with application of burnt cane filter cake (CQTF and burnt cane with joint application of vinasse and filter cake (CQVTF. For reference we used an area of natural vegetation (NV, Cerrado sensu stricto. Treatment CQVTF showed improvement in soil chemical properties, increased inventory levels of total organic carbon – TOC (values ranging from 21.28 to 40.02 Mg ha-1 and humified fractions of soil organic matter in relation to other treatments. The CQS area at a depth of 0-0.05 m, showed the greatest losses of soil TOC stocks (56.3% compared to NV. The adoption of management presented CCV and chemical attributes of the soil TOC stocks equivalent to those observed in areas with CQV CQTF and despite the short period of adoption (3 years. The TOC correlated with the sum of bases (r = 0.76 **, cation exchange capacity (r = 0.59 ** and base saturation (r = 0.63 **, while the humic acids (r = 0.40 ** fulvic acids (r = 0.49 ** and humin (r = 0.59 ** correlated with the cation exchange capacity of the soil. These results indicate that the preservation of trash in the management of cane sugar added to the application of vinasse and filter cake increases the TOC stocks promoting improvement in soil chemical properties.
Field theoretical methods in chemical physics
International Nuclear Information System (INIS)
The language accompanying the use of creation and annihilation operators is found in many scientific fields. The author attempts to bring together the foundations upon which the many and varied applications of field theory have been built. It is demonstrated that the mathematics of second quantization is not limited to quantum mechanics and is a feature of any linear differential equation. Subsequent chapters are: time dependence in field theory; principle of second quantization and statistical mechanics; theory of Green's functions - nomenclature and perturbational calculation; summation of the perturbation expansion; the theory of response functions; applications of the Green's function method to the problems of atomic and molecular structure; application of the Green's function method to spectroscopy. (Auth.)
Rigorous decision of the excess fraction method in absolute distance interferometry
Agurok, Il'ya P.
1997-11-01
Absolute distance interferometry is a promising technology for comprehensive investigation of optical component parameters, including measurement of radii and thicknesses. In special interferometric schematics, it is applicable to measuring parameters of surfaces after grinding and can simplify null corrector design or eliminate its implementation for final testing aspherical surfaces. A universal method for precision length measurement, called 'excess fractions,' was proposed at the end of the last century to calibrate gauges. In this method, the interferometer compares an unknown distance with magnitudes of several wavelengths. The array which consists of the remainders of integer parts of the phase shift between the reference branch of the interferometer and the measuring distance, will be obtained. The proposed consideration of the 'excess fraction' method is based on the Chinese Remainder Theorem. It will be shown that the confidence interval of the obtained distance is equal to the confidence interval of the fractions. Consideration of the finite precision will make the method independent of which units will express, and provides the intervals of unambiguity of the method.
Hybrid method for designing digital FIR filters based on fractional derivative constraints.
Baderia, Kuldeep; Kumar, Anil; Kumar Singh, Girish
2015-09-01
In this manuscript, a hybrid approach based on Lagrange multiplier method and cuckoo search (CS) optimization technique is proposed for the design of linear phase finite impulse response (FIR) filters using fractional derivative constraints. In the proposed method, FIR filter is designed by optimizing the integral squares in passband and stopband from ideal response such that the fractional derivatives of designed filter response become zero at a given frequency point. Lagrange multiplier method is exploited for finding the optimized filter coefficients. Optimal value of fractional derivative constraints for optimized filter coefficients are determined by minimizing the objective function constructed using a sum of maximum passband ripple and maximum stopband ripple in frequency domain using CS algorithm. Performance of the proposed method is evaluated by passband error (ϕ(p)), stopband error (ϕ(s)), stopband attenuation (A(s)), maximum passband ripple (MPR), maximum stopband ripple (MSR) and CPU time. A comparative study of the performance of particle swarm optimization (PSO) and artificial bee colony (ABC) for designing FIR filters using the proposed method is also made. PMID:26142984
Nanostructured Tungsten Materials by Chemical Methods
Wahlberg, Sverker
2011-01-01
Tungsten based-materials are used in many different technical fields, particularly in applications requiring good temperature and/or erosion resistance. Nanostructuring of tungsten alloys and composites has the potential to dramatically improve the materials’ properties, enhancing the performance in present applications or enabling totally new possibilities. Nanostructured WC-Co composites have been the focus of researchers and industries for over two decades. New methods for powder fabricati...
Hampel, Uwe; Bieberle, Andre; Schleicher, Eckhard; Hessel, Günther; Zippe, Cornelius; Friedrich, Hans-Jürgen
2007-06-01
We applied gamma ray tomography to the problem of phase fraction measurement in chemical reactors. Therefore, we used a new tomography device that is operated with a Cs-137 source and a high resolution gamma ray detector. One application example is the reconstruction of the fluid distribution and the measurement of radial gas fraction profiles in a laboratory scale stirred vessel. The tomograph was used to obtain radiographic projections of the averaged gamma ray attenuation for different stirrer speeds along the height of the vessel. With tomographic reconstruction techniques we calculated the angularly averaged radial distribution of the attenuation coefficient for as many as 150 single cross-sectional planes and synthesised from this data set the axial and radial fluid distribution pattern. Further, we exemplarily reconstructed the radial gas fraction distributions induced by the stirrer in the area of the stirrer blades. In a second application the gamma ray measurement system was used to visualise gas inclusions in a water cleaning column that is used to remove hazardous heavy metal species from water.
Xu, Gang; Zhang, You; Shao, Hongbo; Sun, Junna
2016-11-01
Phosphorus (P) recycling or reuse by pyrolyzing crop residue has recently elicited increased research interest. However, the effects of feedstock and pyrolysis conditions on P species have not been fully understood. Such knowledge is important in identifying the agronomic and environmental uses of biochar. Residues of three main Chinese agricultural crops and the biochars (produced at 300°C-600°C) derived from these crops were used to determine P transformations during pyrolysis. Hedley sequential fractionation and (31)P NMR analyses were used in the investigation. Our results showed that P transformation in biochar was significantly affected by pyrolysis temperature regardless of feedstock (Wheat straw, maize straw and peanut husk). Pyrolysis treatment transformed water soluble P into a labile (NaHCO3-Pi) or semi-labile pool (NaOH-Pi) and into a stable pool (Dil. HCl P and residual-P). At the same time, organic P was transformed into inorganic P fractions which was identified by the rapid decomposition of organic P detected with solution (31)P NMR. The P transformation during pyrolysis process suggested more stable P was formed at a higher pyrolysis temperature. This result was also evidenced by the presence of less soluble or stable P species, such as such as poly-P, crandallite (CaAl3(OH)5(PO4)2) and Wavellite (Al3(OH)3(PO4)2·5H2O), as detected by solid-state (31)P NMR in biochars formed at a higher pyrolysis temperature. Furthermore, a significant proportion of less soluble pyrophosphate was identified by solution (2%-35%) and solid-state (8%-53%) (31)P NMR, which was also responsible for the stable P forms at higher pyrolysis temperature although their solubility or stability requires further investigation. Results suggested that a relatively lower pyrolysis temperature retains P availability regardless of feedstock during pyrolysis process. PMID:27343937
Directory of Open Access Journals (Sweden)
W. T. Morgan
2009-12-01
Full Text Available The spatial distribution of aerosol chemical composition and the evolution of the Organic Aerosol (OA fraction is investigated based upon airborne measurements of aerosol chemical composition in the planetary boundary layer across Europe. Sub-micron aerosol chemical composition was measured using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS. A range of sampling conditions were evaluated, including relatively clean background conditions, polluted conditions in North-Western Europe and the near-field to far-field outflow from such conditions. Ammonium nitrate and OA were found to be the dominant chemical components of the sub-micron aerosol burden, with mass fractions ranging from 20–50% each. Ammonium nitrate was found to dominate in North-Western Europe during episodes of high pollution, reflecting the enhanced NO_{x} and ammonia sources in this region. OA was ubiquitous across Europe and concentrations generally exceeded sulphate by 50–100%. A factor analysis of the OA burden was performed in order to probe the evolution across this large range of spatial and temporal scales. Two separate Oxygenated Organic Aerosol (OOA components were identified; one representing an aged-OOA, termed Low Volatility-OOA and another representing fresher-OOA, termed Semi Volatile-OOA on the basis of their mass spectral similarity to previous studies. The factors derived from different flights were not chemically the same but rather reflect the range of OA composition sampled during a particular flight. Significant chemical processing of the OA was observed downwind of major sources in North-Western Europe, with the LV-OOA component becoming increasingly dominant as the distance from source and photochemical processing increased. The measurements suggest that the aging of OA can be viewed as a continuum, with a progression from a less oxidised, semi-volatile component to a highly oxidised, less-volatile component. Substantial amounts of
ALE Fractional Step Finite Element Method for Fluid-Structure Nonlinear Interaction Problem
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
A computational procedure is developed to solve the problems of coupled motion of a structure and a viscous incompressible fluid. In order to incorporate the effect of the moving surface of the structure as well as the free surface motion, the arbitrary Lagrangian-Eulerian formulation is employed as the basis of the finite element spatial discretization. For numerical integration in time, the fraction step method is used. This method is useful because one can use the same linear interpolation function for both velocity and pressure. The method is applied to the nonlinear interaction of a structure and a tuned liquid damper. All computations are performed with a personal computer.
Comparison of Two Methods for the Extraction of Fractionated Rice Bran Protein
Directory of Open Access Journals (Sweden)
Changyuan Wang
2014-01-01
Full Text Available Two different methods for extracting fractionated rice bran protein (FRBP from defatted rice bran were investigated according to the solubility of protein in different extraction solvents. The yields of the obtained proteins and their purity were first compared. Sodium dodecyl sulfate polyacrylamide gel electrophoresis, differential scanning calorimetry, protein surface hydrophobicity, and protein secondary molecular structure analyses were subsequently applied to identify and compare the compositional, structural, and functional characteristics of the obtained proteins. The highest yield (13.8%, w/w and purity (45–47% of FRBP products were obtained using 0.4 M NaCl, 80% ethanol, and 0.01 M NaOH as extraction solvents to fractionate albumin, globulin, prolamin, and glutelin. Several good properties were exhibited, including good functionality, specific denaturation temperature, and enthalpy values, for FRBP products prepared by the above method.
Energy Technology Data Exchange (ETDEWEB)
Wilson, B.W.; Pelroy, R.A.; Mahlum, D.D.
1982-07-01
This report summarizes selected research efforts oriented toward ameliorating the genotoxic potential of direct coal liquefaction materials through modification or optimization of process conditions. The studies described were conducted to evaluate the utility of optimized distillation for coal liquids from the SRC-I process. SRC-I process solvent was distilled into 50/sup 0/F-range boiling point (bp) cuts. Analysis of amino-PAH (APAH) showed that mutagenic APAHs containing 3 or more rings were found primarily in fractions boiling above 750/sup 0/F. Three microbial tester strains were used to screen for genetically active agents in the SRC-I distillate bp cuts. Reverse mutation with the Ames tester strain TA98 demonstrated that mutagens were concentrated in the bp cuts boiling above 700/sup 0/F. For this tester strain most of the genetic activity in these distillates was attributable to chemical fractions enriched in APAH having 3 or more rings. Mutagenicity data obtained with TA98 was in good agreement with sk in carcinogenesis results from the mouse-skin initiation/promotion (in vivo) test system. The strongest response in the forward mutation assay did not occur in the most carcinogenically active fractions. Results of initiation/promotion experiments used to measure the relative potency of bp cuts as initiators of mouse skin carcinogenesis again showed that fractions boiling above 750/sup 0/F. Compounds reaching their highest concentrations in the highest boiling and most carcinogenically active cut included known carcinogens such as benzo(a)pyrene and dimethyl benzanthracene. Thus, all biomedical test results indicate that consideration should be given to conducting distillation so as to minimize, in the distillate product, the concentrations of those biologically active compounds found in cuts boiling above 700/sup 0/C.
Freed, Alan D.; Diethelm, Kai; Gray, Hugh R. (Technical Monitor)
2002-01-01
Fraction-order viscoelastic (FOV) material models have been proposed and studied in 1D since the 1930's, and were extended into three dimensions in the 1970's under the assumption of infinitesimal straining. It was not until 1997 that Drozdov introduced the first finite-strain FOV constitutive equations. In our presentation, we shall continue in this tradition by extending the standard, FOV, fluid and solid, material models introduced in 1971 by Caputo and Mainardi into 3D constitutive formula applicable for finite-strain analyses. To achieve this, we generalize both the convected and co-rotational derivatives of tensor fields to fractional order. This is accomplished by defining them first as body tensor fields and then mapping them into space as objective Cartesian tensor fields. Constitutive equations are constructed using both variants for fractional rate, and their responses are contrasted in simple shear. After five years of research and development, we now possess a basic suite of numerical tools necessary to study finite-strain FOV constitutive equations and their iterative refinement into a mature collection of material models. Numerical methods still need to be developed for efficiently solving fraction al-order integrals, derivatives, and differential equations in a finite element setting where such constitutive formulae would need to be solved at each Gauss point in each element of a finite model, which can number into the millions in today's analysis.
A new MC-based method to evaluate the fission fraction uncertainty at reactor neutrino experiment
Ma, X. B.; Qiu, R. M.; Y. X. Chen
2016-01-01
Uncertainties of fission fraction is an important uncertainty source for the antineutrino flux prediction in a reactor antineutrino experiment. A new MC-based method of evaluating the covariance coefficients between isotopes was proposed. It was found that the covariance coefficients will varying with reactor burnup and which may change from positive to negative because of fissioning balance effect, for example, the covariance coefficient between $^{235}$U and $^{239}$Pu changes from 0.15 to ...
Directory of Open Access Journals (Sweden)
D. Baleanu
2013-01-01
fractional derivatives is based on modified generalized Laguerre polynomials Li(α,β(x with x∈Λ=(0,∞, α>−1, and β>0, and i is the polynomial degree. We implement and develop the modified generalized Laguerre collocation method based on the modified generalized Laguerre-Gauss points which is used as collocation nodes for solving nonlinear multiterm FDEs on the half line.
Comparison of Two Methods for the Extraction of Fractionated Rice Bran Protein
Changyuan Wang; Dan Li; Feng Xu; Tianshu Hao; Min Zhang
2014-01-01
Two different methods for extracting fractionated rice bran protein (FRBP) from defatted rice bran were investigated according to the solubility of protein in different extraction solvents. The yields of the obtained proteins and their purity were first compared. Sodium dodecyl sulfate polyacrylamide gel electrophoresis, differential scanning calorimetry, protein surface hydrophobicity, and protein secondary molecular structure analyses were subsequently applied to identify and compare the co...
Odour Detection Methods: Olfactometry and Chemical Sensors
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Sara Lovascio
2011-05-01
Full Text Available The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc. and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality; this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses are then described, focusing on their better performances for environmental analysis. Odour emission monitoring
Can a fractionally crystallized magma ocean explain the thermo-chemical evolution of Mars?
Plesa, A -C; Breuer, D
2014-01-01
The impact heat accumulated during the late stage of planetary accretion can melt a significant part or even the entire mantle of a terrestrial body, giving rise to a global magma ocean. [...] Assuming fractional crystallization of the magma ocean, dense cumulates are produced close to the surface, largely due to iron enrichment in the evolving magma ocean liquid (Elkins-Tanton et al., 2003). A gravitationally unstable mantle thus forms, which is prone to overturn. We investigate the cumulate overturn and its influence on the thermal evolution of Mars using mantle convection simulations in 2D cylindrical geometry. We present a suite of simulations using different initial conditions and a strongly temperature-dependent viscosity. We assume that all radiogenic heat sources have been enriched during the freezing-phase of the magma ocean in the uppermost 50 km and that the initial steam-atmosphere created by the degassing of the freezing magma ocean was rapidly lost, implying that the surface temperature is set t...
Safety in the Chemical Laboratory--Chemical Management: A Method for Waste Reduction.
Pine, Stanley H.
1984-01-01
Discusses methods for reducing or eliminating waste disposal problems in the chemistry laboratory, considering both economic and environmental aspects of the problems. Proposes inventory control, shared use, solvent recycling, zero effluent, and various means of disposing of chemicals. (JM)
A comparison of 3-D data correlation methods for fractionated stereotactic radiotherapy
International Nuclear Information System (INIS)
Purpose: Stereotactic radiosurgery is currently used to treat patients who are not good candidates for conventional neurosurgical procedures. For treatments of nonvascular tumor cells, it appears that fractionation offers a radiobiological advantage between tumor and normal tissues. Therefore, fractionated stereotactic radiotherapy (FSR) is preferred because it minimizes normal tissue complications and maximizes local tumor control probability. We have implemented a methodology clinically to perform the noninvasive patient repositioning technique. The 3-D data correlation method for high-precision and multiple fraction stereotactic treatments has been presented. Methods and Materials: Three different optimization algorithms (Hooke and Jeeves optimization, simplex optimization, and simulated annealing optimization) are evaluated to calculate the transformation parameters necessary for FSR. A least-square object function is created to perform the 3-D data matching process. By minimizing the unconstrained object function value the best fit can be approached for the reference 3-D data sets. Simulation shows that these algorithms deliver results that are comparable to the previously published correlation algorithm (singular value decomposition [SVD] method). The advantage for optimization algorithms is easily understood and can be readily implemented by using a personal computer (PC). The mathematical framework provides a tool to calculate the transformation matrix which can be used to adjust patient position for fractionated treatments. Therefore, using these algorithms for a high-precision fractionated treatment is possible without an invasive repeat fixation device and has been implemented clinically. A bite plate system was incorporated to acquire 3-D patient data. With a 3-D digital camera localization device, the patient motion can be followed in real time with the system calibrated to the isocenter. Results: Two types of data sets are utilized to study the
Kelly, W. R.; Larimer, J. W.
1977-01-01
The chemical composition of the metal phase of iron meteorites is traced through an idealized traditional history from condensation, oxidation, and accretion in the nebula to melting, segregation, and freezing in a parent body, considering the following fifteen elements: Au, Co, Cu, Fe, Ga, Ge, Ir, Mo, Ni, Os, Pd, Pt, Re, Rh, and Ru. Twelve iron meteorite groups resolved by Scott and Wasson (1975) are considered in the framework of cosmochemical historical analysis. The parent bodies of five of these groups seem to have had a traditional history. The others seem to have had more unusual histories. For example, the composition of the metal in group IVB matches that predicted for the metal condensate at 1270 K, implying accretion at high temperatures; and the metal in group IVA has a composition indicative of aggregates undergoing progressive stages of partial melting.
Trace element distribution in different chemical fractions of False Bay sediments
International Nuclear Information System (INIS)
Trace metals in the aquatic environment are generally concentrated on solid geochemical phases which eventually become incorporated into estuarine and marine sediments. The mechanism of trace metal concentration is believed to be adsorption on various geochemical phases, such as hydrous metal oxides, clays and organic matter. Metals in estuarine sediments can thus be expected to be partitioned between different phases, depending on the concentration of the phase and the strength of the adsorption bond. The bioavailability of sediment-bound metals to deposit-feeding organisms will depend on trace metal partitioning and the kinetics of biological metal uptake from each geochemical phase. The major objective of this study was to establish an analytical procedure involving sequential chemical extractions for the partitioning of particulate trace metals in sediment samples, collected from False Bay. Eight metals were examined, i.e. Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn. X-ray diffraction was also used in the study
Wintertime chemical compositions of coarse and fine fractions of particulate matter in Bolu, Turkey.
Öztürk, Fatma; Keleş, Melek
2016-07-01
Coarse (particulate matter (PM)2.5-10) and fine (PM2.5) fraction of PM samples were collected between December 2014 and February 2015 at an urban sampling site located at the Bolu plain, of the western Black Sea region of Turkey. The collected samples were analyzed in terms of metals (Al, As, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Pb, S, Si, Ti, V, and Zn); elemental carbon (EC); and organic carbon (OC). Elevated concentrations measured in this wintertime study were ∼7.8 μg/m(3) in sum of PM2.5-10 and PM2.5 for SO4 (2-) and ∼59.9 μg/m(3) in PM2.5 for OC. The contributions of primary and secondary OC (POC and SOC, respectively) to total OC mass were 60 and 40 %, respectively, while contribution of SOC to OC increased by up to 74 % in stable atmospheric conditions. The significantly high OC/EC ratio (∼10.1) found in this study relative to other wintertime studies was attributed to increased emissions from residential heating and lower mixing height observed during the study. Two and three factors were resolved by factor analysis for PM2.5-10 and PM2.5, respectively. Two Saharan dust episodes were observed on 31 January and 1 February, during which crustal PM components such as Mg, Si, and Al increased as much as three times their background concentrations. PMID:27048328
Parameter estimation of analog circuits based on the fractional wavelet method
Yong, Deng; He, Zhang
2015-03-01
Aiming at the problem of parameter estimation in analog circuits, a new approach is proposed. The approach is based on the fractional wavelet to derive the Volterra series model of the circuit under test (CUT). By the gradient search algorithm used in the Volterra model, the unknown parameters in the CUT are estimated and the Volterra model is identified. The simulations show that the parameter estimation results of the proposed method in the paper are better than those of other parameter estimation methods. Project supported by the Key Research Project of Sichuan Provincial Department of Education, China (No. 13ZA0186).
Energy Technology Data Exchange (ETDEWEB)
Yang, Xiao-Jun, E-mail: dyangxiaojun@hotmail.com [Department of Mathematics and Mechanics, China University of Mining and Technology, Xuzhou, Jiangsu, 221008 (China); Institute of Applied Mathematics, Qujing Normal University, Qujing 655011 (China); Srivastava, H.M., E-mail: harimsri@math.uvic.ca [Department of Mathematics and Statistics, University of Victoria, Victoria, British Columbia V8W 3R4 (Canada); He, Ji-Huan, E-mail: hejihuan@suda.edu.cn [National Engineering Laboratory for Modern Silk, College of Textile and Clothing Engineering, Soochow University, 199 Ren-ai Road, Suzhou 215123 (China); Baleanu, Dumitru, E-mail: dumitru@cankaya.edu.tr [Department of Mathematics and Computer Sciences, Faculty of Arts and Sciences, Cankaya University, Ankara, 06530 (Turkey); Department of Chemical and Materials Engineering, Faculty of Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah, 21589 (Saudi Arabia); Institute of Space Sciences, Magurele-Bucharest (Romania)
2013-10-15
In this Letter, we propose to use the Cantor-type cylindrical-coordinate method in order to investigate a family of local fractional differential operators on Cantor sets. Some testing examples are given to illustrate the capability of the proposed method for the heat-conduction equation on a Cantor set and the damped wave equation in fractal strings. It is seen to be a powerful tool to convert differential equations on Cantor sets from Cantorian-coordinate systems to Cantor-type cylindrical-coordinate systems.
International Nuclear Information System (INIS)
In this Letter, we propose to use the Cantor-type cylindrical-coordinate method in order to investigate a family of local fractional differential operators on Cantor sets. Some testing examples are given to illustrate the capability of the proposed method for the heat-conduction equation on a Cantor set and the damped wave equation in fractal strings. It is seen to be a powerful tool to convert differential equations on Cantor sets from Cantorian-coordinate systems to Cantor-type cylindrical-coordinate systems.
Method of increasing anhydrosugars, pyroligneous fractions and esterified bio-oil
Steele, Philip H; Yu, Fei; Li, Qi; Mitchell, Brian
2014-12-30
The device and method are provided to increase anhydrosugars yield during pyrolysis of biomass. This increase is achieved by injection of a liquid or gas into the vapor stream of any pyrolysis reactor prior to the reactor condensers. A second feature of our technology is the utilization of sonication, microwave excitation, or shear mixing of the biomass to increase the acid catalyst rate for demineralization or removal of hemicellulose prior to pyrolysis. The increased reactivity of these treatments reduces reaction time as well as the required amount of catalyst to less than half of that otherwise required. A fractional condensation system employed by our pyrolysis reactor is another feature of our technology. This system condenses bio-oil pyrolysis vapors to various desired fractions by differential temperature manipulation of individual condensers comprising a condenser chain.
Well-Posedness of Equations with Fractional Derivative via the Method of Sum
Institute of Scientific and Technical Information of China (English)
Shang Quan BU
2012-01-01
We study the well-posedness of the equations with fractional derivative Dαu(t) =Au(t)+f(t) (0 ≤ t≤ 2π),where A is a closed operator in a Banach space X,0 ＜ α ＜ 1 and Dα is the fractional derivative in the sense of Weyl.Although this problem is not always well-posed in Lp(0,2π;(X)) or periodic continuous function spaces Cper([0,2π];(X）),we show by using the method of sum that it is well-posed in some subspaces of Lp(0,2π; X) or Cper([0,2π]; X).
Developing intake fraction estimates with limited data: Comparison of methods in Mexico City
Stevens, Gretchen; de Foy, Benjamin; West, J. Jason; Levy, Jonathan I.
In order to estimate the health benefits of reducing mobile source emissions, analysts typically use detailed atmospheric models to estimate the change in population exposure that results from a given change in emissions. However, this may not be feasible in settings where data are limited or policy decisions are needed in the short term. Intake fraction (iF), defined as the fraction of emissions of a pollutant or its precursor that is inhaled by the population, is a metric that can be used to compare exposure assessment methods in a health benefits analysis context. To clarify the utility of rapid-assessment methods, we calculate particulate matter iFs for the Mexico City Metropolitan Area using five methods, some more resource intensive than others. First, we create two simple box models to describe dispersion of primary fine particulate matter (PM 2.5) in the Mexico City basin. Second, we extrapolate iFs for primary PM 2.5, ammonium sulfate, and ammonium nitrate from US values using a regression model. Third, we calculate iFs by assuming a linear relationship between emissions and population-weighted concentrations of primary PM 2.5, ammonium nitrate, and ammonium sulfate (a particle composition method). Finally, we estimate PM iFs from detailed atmospheric dispersion and chemistry models run for only a short period of time. Intake fractions vary by up to a factor of five, from 23 to 120 per million for primary PM 2.5. Estimates of 60, 7, and 0.7 per million for primary PM, secondary ammonium sulfate, and secondary ammonium nitrate, respectively, represent credible central estimates, with an approximate factor of two uncertainty surrounding each estimate. Our results emphasize that multiple rapid-assessment methods can provide meaningful estimates of iFs in resource-limited environments, and that formal uncertainty analysis, with special attention to model biases and uncertainty, would be important for health benefits analyses.
International Nuclear Information System (INIS)
Highlights: → The FOICM can shorten the tracking time less than traditional methods. → The proposed method can work under lower solar radiation including thin and heavy clouds. → The FOICM algorithm can achieve MPPT for radiation and temperature changes. → It is easy to implement in a single-chip microcontroller or embedded system. -- Abstract: This paper proposes maximum photovoltaic power tracking (MPPT) for the photovoltaic (PV) array using the fractional-order incremental conductance method (FOICM). Since the PV array has low conversion efficiency, and the output power of PV array depends on the operation environments, such as various solar radiation, environment temperature, and weather conditions. Maximum charging power can be increased to a battery using a MPPT algorithm. The energy conversion of the absorbed solar light and cell temperature is directly transferred to the semiconductor, but electricity conduction has anomalous diffusion phenomena in inhomogeneous material. FOICM can provide a dynamic mathematical model to describe non-linear characteristics. The fractional-order incremental change as dynamic variable is used to adjust the PV array voltage toward the maximum power point. For a small-scale PV conversion system, the proposed method is validated by simulation with different operation environments. Compared with traditional methods, experimental results demonstrate the short tracking time and the practicality in MPPT of PV array.
Templier, J.; Derenne, S.
2006-12-01
It is now well established that riverine dissolved organic matter (DOM) play a major role in environmental processes. However natural organic matter exhibit different properties depending on their sources and the fractions considered. As a result chemical characterization of DOM has appeared essential for a better understanding of their reactivity. The purpose of this work was to characterize all of the DOM at molecular level, including the non-hydrolysable fraction, which is a major part of this OM. To this aim a new analytical approach had to be considered. A combination of spectroscopic and pyrolytic methods has been applied to various fractions of DOM originating from different catchments (French and Amazonian rivers). The fractions were termed hydrophilic, transphilic and colloids according to the IHSS fractionation procedure, and account for at least 70% of the total dissolved organic carbon. Solid state 13C NMR and FTIR afford information on the nature and relative abundance of the chemical functions occurring in macromolecules. Differential thermogravimetric analysis allows to determine the thermal behaviour of the studied material and hence to optimize analytical pyrolysis conditions. Curie point pyrolysis combined to gas chromatography and mass spectrometry leads to identification of characteristic pyrolysis products, some of them being specific of a macromolecular source. Additional information can be provided by thermochemolysis with tetramethylammonium hydroxide (TMAH). TMAH was shown to allow an increase in the efficiency of the cracking of macromolecular structures and an enhancement of the detection of the polar pyrolysis products especially due to methylation of the alcohol, phenol and acid groups. The results obtained have established the importance of terrestrial contribution to DOM. Hydrophobic fractions mainly originate from lignin-derived units, whereas transphilic fractions mostly contain cellulose units together with lignin derived ones and
Hamley-Bennett, C; Lye, G J; Leak, D J
2016-06-01
The effect of time and pressure on the selective extraction of sugar beet pectin using steam pre-treatment on unprocessed Sugar Beet Pulp was evaluated using a design of experiments approach. This process gave the highest solubilisation of pectin oligomers at a relatively low pressure and longer time (5Bar, 24min), whilst leaving the majority of the cellulose fraction intact. This method of steam pre-treatment fits into the concept of a sugar beet biorefinery as it valorises an existing waste stream without requiring any further physical processing such as milling or dilution with water. The residual cellulose fraction was enriched in cellulose and could be effectively fermented into ethanol by yeast after enzymatic digestion, producing 0.48g ethanol per gram of glucose. PMID:26978325
Directory of Open Access Journals (Sweden)
Dwight R. Soares
2007-09-01
Full Text Available Gahnite electron probe microanalyses from three pegmatites (Mirador, Capoeira and Quintos of the Borborema Pegmatitic Province in northeastern Brazil allowed to determine molar compositions ranging from 86.22 to 95.41 mol% gahnite (ZnAl2O4, 1.51 to 6.62 mol% hercynite (Fe2+Al2O4, 0.11 to 5.89 mol% spinel (MgAl2O4, 1.48 to 2.74 mol% galaxite (MnAl2O4, and Zn/FeTotal atomic ratios ranging from 11.53 to 60.87. These data compared with gahnite compositions from albite subtype pegmatites from Cap de Creus, Spain (Zn/FeTotal between 10 and 60 and from the source granite of the Separation Rapids pegmatite field, Ontario, Canada (Zn/FeTotal =3.5 indicate a high degree of fractionation of the studied pegmatites. This interpretation agrees with conclusions based on compositional data of tourmaline (vacancy in X-site 0.42 to 0.49, white mica (K/Rb between 8 and 33, feldspar (K/Rb between 8 and 109, garnet (Mn/(Mn+Fe2+between 0.93 and 0.97 and in Nb-Ta oxides (Mn/(Mn+Fe2+>0.5 in the same pegmatites.Análises via microssonda eletrônica de gahnita de três pegmatitos (Mirador, Capoeira e Quintos da Província Pegmatítica da Borborema, no Nordeste do Brasil, permitiram estabelecer uma composição molar variando entre 86,22 e 95,41 mol% de gahnita (ZnAl2O4, 1,51 e 6,62 mol% de hercinita (Fe2+Al2O4, 0,11 e 5,89 mol% de espinélio (MgAl2O4, 1,48 e 2,74 mol% de galaxita (MnAl2O4 e relação Zn/FeTotal variando entre 11,53 e 60,87. Estes dados comparados com os de gahnita dos pegmatitos subtipo albita de Cap de Creus, Espanha (Zn/FeTotal variando entre 10 e 60 e gahnita de fonte granítica do campo pegmatítico Separation Rapids, Ontário, Canadá (Zn/FeTotal = 3,5 indicam um alto grau de fracionamento dos pegmatitos estudados. Esta interpretação está de acordo com conclusões baseadas em dados de turmalina (vacância no sítio X variando entre 0,42 a 0,49, mica clara (K/Rb variando entre 8 e 33, feldspato (K/Rb variando entre 8 e 109, granada (Mn/(Mn+Fe2
de Jonge, L H; van Laar, H; Hendriks, W H; Dijkstra, J
2013-08-01
A modified rinsing method for the in situ technique was developed to separate, isolate and characterise the soluble (S), the insoluble washout (W-S) and the non-washout fractions (D + U) within one procedure. For non-incubated bags (t = 0 h), this method was compared with the conventional, Combined Fractionation (CF) method that measures the D + U and S fractions in separate steps and subsequently calculates the W-S fraction. The modified method was based on rinsing of nylon bags in a closed vessel containing a buffer solution (pH 6.2) during 1 h, where shaking speeds of 40, 100, and 160 strokes per minutes (spm) were evaluated, and tested for six feed ingredients (faba beans, maize, oats, peas, soya beans and wheat) and four forages (two ryegrass silages and two maize silages). The average recoveries as the sum of all fractions were 0.972 ± 0.041 for N and 0.990 ± 0.050 for starch (mean ± s.d.). The mean W-S fraction increased with increasing shaking speed and varied between 0.017 (N) and 0.083 (starch) at 40 spm and 0.078 (N) and 0.303 (starch) at 160 spm, respectively. For ryegrass silages, the W-S fraction was absent at all shaking speeds, but was present in the CF method. The modified method, in particular at 40 and 100 spm, reduced the loss of small particles during rinsing, resulting in lower W-S and higher D + U fractions for N and starch compared with the CF method. For soya beans and ryegrass silage, the modified method reduced the S fraction of N compared with the CF method. The results obtained at 160 spm showed the best comparison with those from the CF method. The W-S fraction of the feedstuff obtained at 160 spm contained mainly particles smaller than 40 μm (0.908 ± 0.086). In most feedstuff, starch was the most abundant chemical component in the W-S fraction and its content (726 ± 75 g/kg DM) was higher than in the D + U fraction (405 ± 177 g/kg DM). Alkaline-soluble proteins were the dominant N-containing components in the W-S fraction of
Energy Technology Data Exchange (ETDEWEB)
Diantoro, Markus, E-mail: m-diantoror@yahoo.com; Fitrianingsih, Rina, E-mail: m-diantoror@yahoo.com; Mufti, Nandang, E-mail: m-diantoror@yahoo.com; Fuad, Abdulloh, E-mail: m-diantoror@yahoo.com [Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang (UM), Jl. Semarang No. 5 Malang 65145 (Indonesia)
2014-03-24
Nanosilver is currently one of the most common engineered nanomaterials and is used in many applications that lead to the release of silver nanoparticles and silver ions into aqueous systems. Nanosilver also possesses enhanced antimicrobial activity and bioavailability that may less environmental risk compared with other manufactured nanomaterials. Described in this research are the synthesis of silver nanoparticle produced by chemical reduction from silver nitrate (AgNO{sub 3}) solution. As a reducing agent, Sodium Borohydride (NaBH{sub 4}) was used and mercaptosuccinic Acid (MSA) as stabilizer to prevent the nanoparticle from aglomerating. It was also used two kinds of solvent, they are water and methanol. In typical experiment MSA was dissolve in methanol with a number of variation of molarity i.e. 0,03 M, 0,06 M, 0,12 M, 0,15 M, and the mixture was kept under vigorous stirring in an ice bath. A solution of silver nitrate of 340 mg in 6,792 ml water was added. A freshly prepared aqueous solution of sodium borohydride (756,6 mL in 100 mL of water) was added drop wisely. The solution was kept for half an hour for stirring and were allowed to settle down in methanol. The obtained samples then characterized by means of x-ray diffractometer, and scanning electron microscopy, as well as transmission electron microscopy to obtain their structures of silver nanoparticles, morphology, and sizes. It is shown that diameter of silver nanoparticle sized about 24.3 nm (Ag@MSA 0.03 M), 20.4 nm (Ag@MSA 0.06 M), 16.8 nm (Ag@MSA 0.12 M), 16.9 nm (Ag@MSA 0.15 M) which was calculated by Scherrer formula by taking the FWHM from fitting to Gaussian. The phases and lattice parameter showed that there is no significant change in its volume by increasing molarity of stabilizer. In contrast, the size of particles is decreasing.
International Nuclear Information System (INIS)
Nanosilver is currently one of the most common engineered nanomaterials and is used in many applications that lead to the release of silver nanoparticles and silver ions into aqueous systems. Nanosilver also possesses enhanced antimicrobial activity and bioavailability that may less environmental risk compared with other manufactured nanomaterials. Described in this research are the synthesis of silver nanoparticle produced by chemical reduction from silver nitrate (AgNO3) solution. As a reducing agent, Sodium Borohydride (NaBH4) was used and mercaptosuccinic Acid (MSA) as stabilizer to prevent the nanoparticle from aglomerating. It was also used two kinds of solvent, they are water and methanol. In typical experiment MSA was dissolve in methanol with a number of variation of molarity i.e. 0,03 M, 0,06 M, 0,12 M, 0,15 M, and the mixture was kept under vigorous stirring in an ice bath. A solution of silver nitrate of 340 mg in 6,792 ml water was added. A freshly prepared aqueous solution of sodium borohydride (756,6 mL in 100 mL of water) was added drop wisely. The solution was kept for half an hour for stirring and were allowed to settle down in methanol. The obtained samples then characterized by means of x-ray diffractometer, and scanning electron microscopy, as well as transmission electron microscopy to obtain their structures of silver nanoparticles, morphology, and sizes. It is shown that diameter of silver nanoparticle sized about 24.3 nm (Ag@MSA 0.03 M), 20.4 nm (Ag@MSA 0.06 M), 16.8 nm (Ag@MSA 0.12 M), 16.9 nm (Ag@MSA 0.15 M) which was calculated by Scherrer formula by taking the FWHM from fitting to Gaussian. The phases and lattice parameter showed that there is no significant change in its volume by increasing molarity of stabilizer. In contrast, the size of particles is decreasing
International Nuclear Information System (INIS)
Chemical methods to predict the bioavailable fraction of organic contaminants are usually validated in the literature by comparison with established bioassays. A soil spiked with polycyclic aromatic hydrocarbons (PAHs) was aged over six months and subjected to butanol, cyclodextrin and tenax extractions as well as an exhaustive extraction to determine total PAH concentrations at several time points. Earthworm (Eisenia fetida) and rye grass root (Lolium multiflorum) accumulation bioassays were conducted in parallel. Butanol extractions gave the best relationship with earthworm accumulation (r2 ≤ 0.54, p ≤ 0.01); cyclodextrin, butanol and acetone-hexane extractions all gave good predictions of accumulation in rye grass roots (r2 ≤ 0.86, p ≤ 0.01). However, the profile of the PAHs extracted by the different chemical methods was significantly different (p < 0.01) to that accumulated in the organisms. Biota accumulated a higher proportion of the heavier 4-ringed PAHs. It is concluded that bioaccumulation is a complex process that cannot be predicted by measuring the bioavailable fraction alone. - The ability of chemical methods to predict PAH accumulation in Eisenia fetida and Lolium multiflorum was hindered by the varied metabolic fate of the different PAHs within the organisms.
Chemical reactor and method for chemically converting a first material into a second material
Kong, Peter C.
2008-04-08
A chemical reactor and method for converting a first material into a second material is disclosed and wherein the chemical reactor is provided with a feed stream of a first material which is to be converted into a second material; and wherein the first material is combusted in the chemical reactor to produce a combustion flame, and a resulting gas; and an electrical arc is provided which is passed through or superimposed upon the combustion flame and the resulting gas to facilitate the production of the second material.
Institute of Scientific and Technical Information of China (English)
XU Mingyu; TAN Wenchang
2006-01-01
From point of view of physics, especially of mechanics, we briefly introduce fractional operators (with emphasis on fractional calculus and fractional differential equations) used for describing intermediate processes and critical phenomena in physics and mechanics, their progress in theory and methods and their applications to modern mechanics. Some authors' researches in this area in recent years are included. Finally, prospects and evaluation for this subject are made.
Institute of Scientific and Technical Information of China (English)
Yi-rang Yuan
2004-01-01
For compressible two-phase displacement problem,the modified upwind finite difference fractional steps schemes are put forward.Some techniques,such as calculus of variations,commutative law of multiplication of difference operators,decomposition of high order difference operators,the theory of prior estimates and techniques are used.Optimal order estimates in L 2 norm are derived for the error in the approximate solution.This method has already been applied to the numerical simulation of seawater intrusion and migration-accumulation of oil resources.
Methods of remote surface chemical analysis for asteroid missions
International Nuclear Information System (INIS)
Different remote sensing methods are discussed which can be applied to investigate the chemical composition of minor bodies of the Solar System. The secondary-ion method, remote laser mass-analysis and electron beam induced X-ray emission analysis are treated in detail. Relative advantages of these techniques are analyzed. The physical limitation of the methods: effects of solar magnetic field and solar wind on the secondary-ion and laser methods and the effect of electrostatic potential of the space apparatus on the ion and electron beam methods are described. First laboratory results of remote laser method are given. (D.Gy.)
Brittain, S R; Cox, A G; Tomos, A D; Paterson, E; Siripinyanond, A; McLeod, C W
2012-03-01
Flow field flow fractionation (FlFFF) in combination with inductively coupled plasma mass spectrometry (ICP-MS) was used to study the chemical speciation of U and trace metals in depleted uranium (DU) contaminated soils. A chemical extraction procedure using sodium pyrophosphate, followed by isolation of humic and fulvic substances was applied to two dissimilar DU contaminated sample types (a sandy soil and a clay-rich soil), in addition to a control soil. The sodium pyrophosphate fractions of the firing range soils (Eskmeals and Kirkcudbright) were found to contain over 50% of the total U (measured after aqua regia digestion), compared to approximately 10% for the control soil. This implies that the soils from the contaminated sites contained a large proportion of the U within more easily mobile soil fractions. Humic and fulvic acid fractions each gave characteristic peak maxima for analytes of interest (Mn, Fe, Cu, Zn, Pb and U), with the fulvic acid fraction eluting at a smaller diameter (approximately 2.1 nm on average) than the humic fraction (approximately 2.4 nm on average). DU in the fulvic acid fraction gave a bimodal peak, not apparent for other trace elements investigated, including natural U. This implies that DU interacts with the fulvic acid fraction in a different way to all other elements studied. PMID:22237634
García-Estévez, Ignacio; Escribano-Bailón, M Teresa; Rivas-Gonzalo, Julián C; Alcalde-Eon, Cristina
2010-02-15
During maturation and ageing in oak barrels wines improve their organoleptic properties. Ellagitannins can be released from wood to the wine and be involved in oxidation reactions and seem to influence the astringency and colour properties of the wine. Nevertheless, the ellagitannins levels are lower than those of other wine constituents and, consequently, they are not easily detected. This study has developed a two-step fractionation method consisting of a solid phase extraction in C-18 Sep-Pak cartridges followed by size exclusion chromatography in hand-packed Sephadex LH-20 minicolumn for the detection of oak ellagitannins in different types of wines. An HPLC method has also been developed which allows the separation of compounds with the same m/z ratios, facilitating the ellagitannin identification by means of the mass spectrometric analyses. The main oak ellagitannins (grandinin, vescalagin, roburin E and castalagin) were isolated, detected separately and identified in a spiked wine and in three real ones, proving the usefulness of the fractionation method. PMID:20103159
SOLA-VOF, 2-D Transient Hydrodynamic Using Fractional Volume of Fluid Method
International Nuclear Information System (INIS)
1 - Description of problem or function: SOLA-VOF is a program for the solution of two-dimensional transient fluid flow with free boundaries, based on the concept of a fractional volume of fluid (VOF). Its basic mode of operation is for single fluid calculations having multiple free surfaces. However, SOLA-VOF can also be used for calculations involving two fluids separated by a sharp interface. In either case, the fluids may be treated as incompressible or as having limited compressibility. Surface tension forces with wall adhesion are permitted in both cases. Internal obstacles may be defined by blocking out any desired combination of cells in the mesh, which is composed of rectangular cells of variable size. 2 - Method of solution: The basis of the SOLA-VOF method is the fractional volume of fluid scheme for tracking free boundaries. In this technique, a function F(x,y,t) is defined whose value is unity at any point occupied by fluid and zero elsewhere. When averaged over the cells of a computational mesh, the average value of F in a cell is equal to the fractional volume of the cell occupied by fluid. In particular, a unit value of F corresponds to a cell full of fluid, whereas a zero value indicates that the cell contains no fluid. Cells with F values between zero and one contain a free surface. SOLA-VOF uses an Eulerian mesh of rectangular cells having variable sizes. The fluid equations solved are the finite difference approximations of the Navier-Stokes equations. 3 - Restrictions on the complexity of the problem: The setting of array dimensions is controlled through PARAMETER statements
Indian Academy of Sciences (India)
EMRULLAH YA¸SAR; ILKER BURAK GIRESUNLU
2016-08-01
In this work, we present ($G' /G, 1/G$)-expansion method for solving fractional differential equations based on a fractional complex transform. We apply this method for solving space–time fractional Cahn--Allen equation and space--time fractional Klein–Gordon equation. The fractional derivatives are described in the sense of modified Riemann--Lioville. As a result of some exact solution in the form of hyperbolic, trigonometric and rational solutions are deduced. The obtained solutions may be used for explaining of some physical problems.The($G' /G, 1/G$)-expansion method has a wider applicability for nonlinear equations. We have verified all the obtained solutions with the aid of Maple.
A comparison of 3-D data correlation methods for fractionated stereotactic radiotherapy (FSR)
International Nuclear Information System (INIS)
Purpose/Objective: Stereotactic Radiosurgery is currently used to treat patients who are not good candidates for conventional neurosurgical procedures. For treatments of nonvascular tumor cells, it appears that fractionation will offer a radiological advantage between tumor and normal tissues. Therefore, Fractionated Stereotactic Radiotherapy (FSR) is preferred because it minimizes normal tissue complications and maximizes local tumor control probability. We have implemented a methodology clinically to perform the non-invasive patient repositioning technique. The 3-D data correlation method for high precision and multiple fraction stereotactic treatments has been presented. Materials and Methods: Three different optimization algorithms (Hooke and Jeeves optimization, Simplex optimization, and Simulated Annealing optimization) are evaluated to calculate the transformation parameters necessary for FSR. These algorithms are based on rigid body transformation in which the patient surfaces are considered as reference. A least-square object function is created to perform the 3-D data matching process. By minimizing the unconstrained object function value the best fit can be approached for the reference 3-D data sets. Simulation shows that these algorithms give results which are comparable to the previously published correlation algorithm (Singular Value Decomposition (SVD) method). The advantage is that these algorithms are easily understood and can be readily implemented using a personal computer. The mathematical framework provides a tool to calculate the transformation matrix which can be used to adjust patient position for fractionated treatment. Therefore, using these algorithms for a high precision fractionated treatment is possible without invasive repeat fixation device. A bite plate system was incorporated to acquire 3-D patient data. With 3-D digital camera localization device, the patient motion can be followed in real time with the system calibrated to the
Directory of Open Access Journals (Sweden)
Alberto de J. Oliveros-Bastidas
2013-01-01
Full Text Available Dipteryx odorata (Aubl. Willd. is a tall arboreal species native to Central and Northern South America. This paper describes the chemical characterization and phytotoxic potential of polar and non-polar extracts from D. odorata seeds. Structural determinations were accomplished by chemical derivatization and analyzed by GC/MS. The chemical composition of the non-polar fraction (hexane and dichloromethane presented fatty acids as major constituent. Medium polar and polar fractions (ethyl acetate and ethanol: water contained carboxylic acid and high 6,7-Dyhidroxycoumarin-β-D-glucopyranoside content, not previously reported for seeds of D. odorata. Extracts showed a significant level of phytotoxic activity, correlated to the content of coumarin derivatives, predominantly in the polar fraction.
Li, R C; Schentag, J J; Nix, D E
1993-01-01
The checkerboard technique leading to the fractional inhibitory concentration indexes and the killing curve method are currently the most widely used methods to study antibiotic combinations. For both methods, experimental conditions and interpretation criteria are somewhat arbitrary. The relevance of the fractional inhibitory concentration index computation, in the classic case of additivity [P = d1/(D1)p + d2/(D2)p, where d1 and d2 are the doses of drugs 1 and 2 in combination to produce an...
FINITE ELEMENT METHOD AND ANALYSIS FOR CHEMICAL-FLOODING SIMULATION
Institute of Scientific and Technical Information of China (English)
YUAN Yirang
2000-01-01
This article discusses the enhanced oil recovery numerical simulation of the chemical-flooding (such as surfactants, alcohol, polymers) composed of three-dimensional multicomponent, multiphase and incompressible mixed fluids. The mathematical model can be described as a coupled system of nonlinear partial differential equations with initialboundary value problems. From the actual conditions such as the effect of cross interference and the three-dimensional characteristic of large-scale science-engineering computation, this article puts forward a kind of characteristic finite element fractional step schemes and obtain the optimal order error estimates in L2 norm. Thus we have thoroughly solved the well-known theoretical problem proposed by a famous scientist, R. E. Ewing.
Error analysis of semidiscrete finite element methods for inhomogeneous time-fractional diffusion
Jin, B.
2014-05-30
© 2014 Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved. We consider the initial-boundary value problem for an inhomogeneous time-fractional diffusion equation with a homogeneous Dirichlet boundary condition, a vanishing initial data and a nonsmooth right-hand side in a bounded convex polyhedral domain. We analyse two semidiscrete schemes based on the standard Galerkin and lumped mass finite element methods. Almost optimal error estimates are obtained for right-hand side data f (x, t) ε L∞ (0, T; Hq(ω)), ≤1≥ 1, for both semidiscrete schemes. For the lumped mass method, the optimal L2(ω)-norm error estimate requires symmetric meshes. Finally, twodimensional numerical experiments are presented to verify our theoretical results.
Application of the method of continued fractions for electron scattering by linear molecules
International Nuclear Information System (INIS)
The method of continued fractions (MCF) of Horacek and Sasakawa is adapted for the first time to study low-energy electron scattering by linear molecules. Particularly, we have calculated the reactance K-matrices for an electron scattered by hydrogen molecule and hydrogen molecular ion as well as by a polar LiH molecule in the static-exchange level. For all the applications studied herein. the calculated physical quantities converge rapidly, even for a strongly polar molecule such as LiH, to the correct values and in most cases the convergence is monotonic. Our study suggests that the MCF could be an efficient method for studying electron-molecule scattering and also photoionization of molecules. (Author)
Error Estimates for a Semidiscrete Finite Element Method for Fractional Order Parabolic Equations
Jin, Bangti
2013-01-01
We consider the initial boundary value problem for a homogeneous time-fractional diffusion equation with an initial condition ν(x) and a homogeneous Dirichlet boundary condition in a bounded convex polygonal domain Ω. We study two semidiscrete approximation schemes, i.e., the Galerkin finite element method (FEM) and lumped mass Galerkin FEM, using piecewise linear functions. We establish almost optimal with respect to the data regularity error estimates, including the cases of smooth and nonsmooth initial data, i.e., ν ∈ H2(Ω) ∩ H0 1(Ω) and ν ∈ L2(Ω). For the lumped mass method, the optimal L2-norm error estimate is valid only under an additional assumption on the mesh, which in two dimensions is known to be satisfied for symmetric meshes. Finally, we present some numerical results that give insight into the reliability of the theoretical study. © 2013 Society for Industrial and Applied Mathematics.
Determination of OH groups by wet chemical methods
Czech Academy of Sciences Publication Activity Database
Kuráň, P.; Janoš, P.; Madronová, L.; Novák, František
New York : Nova Science Publisher, 2011 - (Madronová, L.), s. 47-60 ISBN 978-1-61668-965-0. - (Chemistry Research and Applications) Institutional research plan: CEZ:AV0Z60660521 Keywords : determination * OH groups * wet chemical methods Subject RIV: CB - Analytical Chemistry, Separation
International Nuclear Information System (INIS)
We devised a method of analyzing a regional fat fraction using a modulus and real multiple gradient-echo (MRM-GRE) 4-7 echo Dixon sequence. The regional fat fraction was calculated with a theoretically fitted signal-intensity curve for multiple GRE images at each echo time (id est (i.e.), 4-7 echoes.) on a 1.5 Tesla MRI to correct T2 decay and phase cycling. Then the real image of the first echo was used to differentiate between the areas above and below the 50 percent fat fraction. To eliminate the T1-effect, the flip angle was set at 12 degrees. Fat fractions of the phantom with MRM-GRE were compared with those using conventional double-GRE and other MRI techniques. Fat fractions of liver and spinal bone marrow in healthy volunteers were determined during a breath-hold. The fat fraction of the phantom obtained by the MRM-GRE method tended to agree with the actual fat fraction. On the other hand, in both the phantom and in healthy volunteers, the double-GRE was underestimated owing to T2 decay. The MRM-GRE method enables simple, accurate analysis of the regional fat fraction. (author)
Morais, A P; Pino, A V; Souza, M N
2016-08-01
This in vitro study evaluated the diagnostic performance of an alternative electric bioimpedance spectroscopy technique (BIS-STEP) detect questionable occlusal carious lesions. Six specialists carried out the visual (V), radiography (R), and combined (VR) exams of 57 sound or non-cavitated occlusal carious lesion teeth classifying the occlusal surfaces in sound surface (H), enamel caries (EC), and dentinal caries (DC). Measurements were based on the current response to a step voltage excitation (BIS-STEP). A fractional electrical model was used to predict the current response in the time domain and to estimate the model parameters: Rs and Rp (resistive parameters), and C and α (fractional parameters). Histological analysis showed caries prevalence of 33.3% being 15.8% hidden caries. Combined examination obtained the best traditional diagnostic results with specificity = 59.0%, sensitivity = 70.9%, and accuracy = 60.8%. There were statistically significant differences in bioimpedance parameters between the H and EC groups (p = 0.016) and between the H and DC groups (Rs, p = 0.006; Rp, p = 0.022, and α, p = 0.041). Using a suitable threshold for the Rs, we obtained specificity = 60.7%, sensitivity = 77.9%, accuracy = 73.2%, and 100% of detection for deep lesions. It can be concluded that BIS-STEP method could be an important tool to improve the detection and management of occlusal non-cavitated primary caries and pigmented sites. PMID:27587136
Chemical leaching methods and measurements of marine labile particulate Fe
Revels, B. N.; John, S.
2012-12-01
Iron (Fe) is an essential nutrient for life. Yet its low solubility and concentration in the ocean limits marine phytoplankton productivity in many regions of the world. Dissolved phase Fe (0.4μm) may contain an important, labile reservoir of Fe that may also be available to phytoplankton. However, concentration data alone cannot elucidate the sources of particulate Fe to the ocean and to what extent particulate iron may support phytoplankton growth. Isotopic analysis of natural particles may help to elucidate the biogeochemical cycling of Fe, though it is important to find a leaching method which accesses bioavailable Fe. Thirty-three different chemical leaches were performed on a marine sediment reference material, MESS-3. The combinations included four different acids (25% acetic acid, 0.01M HCl, 0.5M HCl, 0.1M H2SO4 at pH2), various redox conditions (0.02M hydroxylamine hydrochloride or 0.02M H2O2), three temperatures (25°C, 60°C, 90°C), and three time points (10 minutes, 2 hours, 24 hours). Leached Fe concentrations varied from 1mg/g to 35mg/g, with longer treatment times, stronger acids, and hotter temperatures generally associated with an increase in leached Fe. δ56Fe in these leaches varied from -1.0‰ to +0.2‰. Interestingly, regardless of leaching method used, there was a very similar relationship between the amount of Fe leached from the particles and the δ56Fe of this iron. Isotopically lighter δ56Fe values were associated with smaller amounts of leached Fe whereas isotopically heavier δ56Fe values were associated with larger amounts of leached Fe. Two alternate hypotheses could explain these data. Either, the particles may contain pools of isotopically light Fe that are easily accessed early in dissolution, or isotopically light Fe may be preferentially leached from the particle due to a kinetic isotope effect during dissolution. To explore the first hypothesis, we modeled dissolution of Fe from particles assuming two separate pools, labile
Crow, S. E.
2011-12-01
Physical separation of soil into various fractions has long been used to address questions concerning mechanisms of soil organic matter stabilization, processes contributing to soil carbon (C) accumulation, and the effects of land use, climate change, and management practice on soil quality and carbon sequestration. However, no published method works well for every soil, ecosystem, or research question. Often a chosen method does not effectively separate soil into C pools that differ in mean residence time (MRT) and sensitivity to change, which can complicate the interpretation of results. Soil C is stabilized by a variety of mechanisms and radiocarbon-based estimates of MRT can reveal the integrated effects of these mechanisms on bulk soil C storage; radiocarbon-based estimates of MRT on isolated soil fractions separated by a carefully chosen method can reveal internal C dynamics invisible to the bulk soil methods. A variety of soils collected around Hawaii (Mollisol, Oxisol, Andisol) were fractionated by several common methods and the radiocarbon-based MRT was estimated for comparison among fractions, soils, and methods. In some cases, depending on the research question of interest, aspects of different methods could be combined to reveal changes in soil C pools on both short and long time frames. For example, for a cultivated, mixed-mineralogy Mollisol, a method that combined a density separation at 1.8 g mL-1 for free light fraction, then calibrated sonication to disrupt aggregates for an occluded fraction, then further sequential fractionation at 2.0 g -1could produce soil C pools with turnover of 3.5 yr (free light fraction), 10 yr (occluded light fraction), 714 yr (1.8-2.0 fraction), and 2090 yr (Andisol, land conversion from old-growth native forest to 80 yr of pasture increased bulk soil C stock in the top 0-15 cm of mineral soil by 26%; however, sequential density separation into 7 fractions revealed 50-69% increases in C within low density fractions with
International Nuclear Information System (INIS)
Summary: Different analytical procedures are being employed in the world to quantify the chelated portion in a Zn-EDTA fertilizer. Agriculture Department, Government of the Punjab is following Shahid's analytical method in this regard. This method is based on Ion-chromatography (IC) that separates the mineral zinc (Zn) from an adulterated Zn-EDTA fertilizer sample i.e. mixture of mineral and chelated Zn fractions. To find out its effectiveness and suitability, this comparative study was carried out by analyzing adulterated, non-adulterated Zn-EDTA standard and Zn-EDTA samples taken from market in thrice following three methods namely Shahid's (IC) analytical method, Atomic Absorption Spectrophotometric (AAS) method based on the principle of precipitating the mineral Zn fraction at high pH value by using alkali solution of suitable concentration and analysis of filtrate containing only chelated fraction and Association of Official Analytical Chemists (AOAC) method FM-841 respectively. Adulterated Zn-EDTA samples were prepared by mixing of known quantity of mineral Zn with chelated Zn-EDTA standard. The results showed that Shahid's analytical method and AAS method, both successfully estimated the chelated fraction. The AOAC FM-841 method was insensitive to put a ceiling on the mineral fraction hence did not furnish the reliable results. The Shahid's analytical method was selected being equallyeffective to produce reliable results both for solid and liquid Zn-EDTA samples. The AAS method was comparable in only liquid samples. (author)
DEFF Research Database (Denmark)
Arnau, E G; Andersen, Klaus Ejner; Bruze, M;
2000-01-01
Fragrance materials are among the most common causes of allergic contact dermatitis. The aim of this study was to identify in a perfume fragrance allergens not included in the fragrance mix, by use of bioassay-guided chemical fractionation and chemical analysis/structure-activity relationships...... (SARs). The basis for the investigation was a 45-year-old woman allergic to her own perfume. She had a negative patch test to the fragrance mix and agreed to participate in the study. Chemical fractionation of the perfume concentrate was used for repeated patch testing and/or repeated open application...... chemical structure, indicating an ability to modify skin proteins and thus behave as a skin sensitizer, were tested on the patient. The patient reacted positively to the synthetic fragrance p-t-butyl-alpha-methylhydrocinnamic aldehyde (Lilial), a widely used fragrance compound not present in the fragrance...
Cachada, A; Pereira, R; da Silva, E Ferreira; Duarte, A C
2014-02-15
The evaluation of the available fraction of hydrophobic organic contaminants (HOCs) is extremely important for assessing their risk to the environment and human health. This available fraction, which can be solubilized and/or easily extracted, is believed to be the most accessible for bioaccumulation, biosorption and/or transformation by organisms. Based on this, two main types of chemical methods have been developed, closely related to the concepts of bioaccessibility and freely available concentrations: non-exhaustive extractions and biomimetic methods. Since bioavailability is species and compound specific, this work focused only in one of the most widespread group of HOCs in soils: polycyclic aromatic hydrocarbons (PAHs). This study aims at producing a state of the art knowledge base on bioavailability and chemical availability of PAHs in soils, clarifying which chemical methods can provide a better prediction of an organism exposure, and which are the most promising ones. Therefore, a review of the processes involved on PAHs availability to microorganisms, earthworms and plants was performed and the outputs given by the different chemical methods were evaluated. The suitability of chemical methods to predict bioavailability of the 16 US EPA PAHs in dissimilar naturally contaminated soils was not yet demonstrated, being especially difficult for high molecular weight compounds. Even though the potential to predict microbial mineralization using non-exhaustive extractions is promising, it will be very difficult to achieve for earthworms and plants, due to the complexity of accumulation mechanisms which are not taken into account by chemical methods. Yet, the existing models could be improved by determining compound, species and site specific parameters. Moreover, chemical availability can be very useful to understand the bioavailability processes and the behavior of PAHs in soils. The inclusion of chemical methods on risk assessment has been suggested and it is
International Nuclear Information System (INIS)
In this Letter, an enhanced Adomian decomposition method which introduces the h-curve of the homotopy analysis method into the standard Adomian decomposition method is proposed. Some examples prove that this method can derive successfully approximate rational Jacobi elliptic function solutions of the fractional differential equations.
Borges, Thays H; Cabrera-Vique, Carmen; Seiquer, Isabel
2015-07-01
The antioxidant activity and the total phenolic content (TPC) of six Spanish commercial monovarietal extra virgin olive oils (Arbequina, Cornicabra, Hojiblanca, Manzanilla, Picual and Picudo) were evaluated in chemical extracts and in bioaccessible fractions (BF) obtained after in vitro digestion. Moreover, the effects of the BF on cell viability and the generation of reactive oxygen species (ROS) were investigated in Caco-2 cell cultures. The in vitro digestion process increased the TPC and antioxidant activity evaluated by different methods (ABTS, DPPH and FRAP) compared with chemical extracts. After digestion, the Picual variety showed better beneficial effects in preserving cell integrity than the other varieties studied. Significant reductions of ROS production were observed after incubation of Caco-2 cells with the BF of all the varieties and, moreover, a protective effect against the oxidative stress induced by t-BOOH was shown for Arbequina, Cornicabra, Hojiblanca, Manzanilla and Picual. These findings seem to be an additional reason supporting the health benefits of Spanish extra virgin olive oil varieties. Multivariate factor analysis and principal component analysis were applied to assess the contribution of antioxidant activity and TPC, before and after digestion, to the characterization of the different varieties. PMID:26087367
International Nuclear Information System (INIS)
The establishment of code system for BWR safety analysis is now in progress at Institute of Nuclear Safety (INS), in order to predict the onset of boiling transition (BT) in nuclear fuel assemblies in any thermal-hydraulic condition without relying on the thermal-hydraulic characteristic data provided by licensee. The prediction method for void fraction distribution across cross section of BWR fuel assemblies has been developed based on multi-dimensional two-fluid model. Lift forces working on bubbles and void diffusion that can not be handled with one-dimensional analysis were considered. Comparisons between calculated results and experimental data obtained from thermal-hydraulic tests of PWR and BWR mock-up fuel assemblies showed good agreement. Lift force models have been empirical and further studies were needed, but the calculations showed the possibility of applying these models to multi-dimensional gas-liquid two-phase flow analysis. (author)
Dynamic Flow-through Methods for Metal Fractionation in Environmental Solid Samples
DEFF Research Database (Denmark)
Miró, Manuel; Hansen, Elo Harald; Petersen, Roongrat
the ecotoxicological significance of metal ions in solid environmental samples. The background of end-over-end fractionation for releasing metal species bound to particular soil phases is initially discussed, its relevant features and limitations being thoroughly described. However, taking into......Accummulation of metal ions in different compartments of the biosphere and their possible mobilization under changing environmental conditions induce a pertubation of the ecosystem and may cause adverse health effects. Nowadays, it is widely recognized that the information on total content of...... account that naturally occurring processes always take place under dynamic conditions, recent trends have been focused on the development of alternative flow-through dynamic methods aimed at mimicking environmental events more correctly than their classical extraction counterparts. In this lecture...
Specific absorbed fractions of energy at various ages from internal photon sources: 1, Methods
International Nuclear Information System (INIS)
Specific absorbed fractions (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. This volume outlines various methods used to compute the PHI-values and describes how the ''best'' estimates recommended by us are chosen. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target organ from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with the methods at photon energies below 200 keV. 41 refs., 25 figs., 23 tabs
EFFECTIVE SOLUTION METHOD OF CHEMICAL REACTION KINETICS WITH DIFFUSE
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The time integration method with four-order accuracy, self-starting and implicit for the diffuse chemical reaction kinetics equation or the transient instantaneous temperature filed equation was presented. The examples show that both accuracy and stability are better than Runge-Kutta method with four-order. The coefficients of the equation are stored with sparse matrix pattern, so an algorithm is presented which combines a compact storage scheme with reduced computation cost. The computation of the competitive and consecutive reaction in the rotating packed bed, taken as examples,shows that the method is effective.
Directory of Open Access Journals (Sweden)
Huitzilin Yépez-Martínez
2015-01-01
Full Text Available The fractional derivatives in the sense of the modified Riemann-Liouville derivative and Feng’s first integral method are employed to obtain the exact solutions of the nonlinear space-time fractional ZKBBM equation and the nonlinear space-time fractional generalized Fisher equation. The power of this manageable method is presented by applying it to the above equations. Our approach provides first integrals in polynomial form with high accuracy. Exact analytical solutions are obtained through establishing first integrals. The present method is efficient and reliable, and it can be used as an alternative to establish new solutions of different types of fractional differential equations applied in mathematical physics.
Institute of Scientific and Technical Information of China (English)
Si Gang-Quan; Sun Zhi-Yong; Zhang Yan-Bin
2011-01-01
This paper investigates the synchronization between integer-order and fractional-order chaotic systems.By introducing fractional-order operators into the controllers,the addressed problem is transformed into a synchronization one among integer-order systems.A novel general method is presented in the paper with rigorous proof.Based on this method,effective controllers are designed for the synchronization between Lorenz systems with an integer order and a fractional order,and for the synchronization between an integer-order Chen system and a fractional-order Liu system.Numerical results,which agree well with the theoretical analyses,are also given to show the effectiveness of this method.
A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels
Directory of Open Access Journals (Sweden)
Huajun Li
2016-01-01
Full Text Available Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA. Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers’ works.
DEFF Research Database (Denmark)
Larsen, Kirsten Kolbjørn; Wielandt, Daniel Kim Peel; Schiller, Martin;
2016-01-01
in the mass-bias corrected 53Cr/52Cr (μ53Cr* of 5.2ppm) and 54Cr/52Cr (μ54Cr* of 13.5ppm) components used to infer chronometric and nucleosynthetic information in meteorites. To mitigate these fractionation effects, we developed strategic chemical sample pre-treatment procedures that ensure high and...
Methods for describing airborne fractions of free fall spills of powders and liquids
International Nuclear Information System (INIS)
Pacific Northwest Laboratory developed calculational methods to characterize aerosols produced in hypothetical spill accidents. These methods were developed for the US Nuclear Regulatory Commission to use when evaluating the consequence of postulated accidents for safety analyses and environmental impact statements. Basic physical properties and mechanistic descriptions of spill events were used as a basis for the methods. Source term models consist of equations that can be used to estimate the mass airborne and particle size distribution of aerosols produced by spills of powders and solutions. Experimental data from Sutter et al. (1981) and Ballinger and Hodgson (1986) were emphasized in the models. Parameter ranges for this data were spill height 1 to 3 m, powder mass 25 to 1000 g, and liquid volume 125 to 1000 ml. Liquids spilled included slurries and solutions of varying viscosities. Liquid spills differed from powders in that an aerosol was produced on impact instead of during the fall. The fraction airborne from liquid spills (including viscous solutions and slurries) correlated well with three dimensionless numbers: the Archimedes number, the Froude number, and a density ratio. Liquid aerosol parameters were statistical descriptions of the log-normal distributions. A computer code was developed to model powder spills. In the code, the mass airborne was assumed proportional to the drag force on the power as it falls. The proportionality factor was empirically found to be a function of a dimensionless number, the Galileo number. 16 refs., 2 figs., 13 tabs
Fractional Complex Transform for Fractional Differential Equations
Li, Zheng-Biao; He, Ji-Huan
2010-01-01
Fractional complex transform is proposed to convert fractional differential equations into ordinary differential equations, so that all analytical methods devoted to advanced calculus can be easily applied to fractional calculus. Two examples are given.
Novel selection methods for DNA-encoded chemical libraries
Chan, Alix I.; McGregor, Lynn M.; Liu, David R.
2015-01-01
Driven by the need for new compounds to serve as biological probes and leads for therapeutic development and the growing accessibility of DNA technologies including high-throughput sequencing, many academic and industrial groups have begun to use DNA-encoded chemical libraries as a source of bioactive small molecules. In this review, we describe the technologies that have enabled the selection of compounds with desired activities from these libraries. These methods exploit the sensitivity of in vitro selection coupled with DNA amplification to overcome some of the limitations and costs associated with conventional screening methods. In addition, we highlight newer techniques with the potential to be applied to the high-throughput evaluation of DNA-encoded chemical libraries. PMID:25723146
Institute of Scientific and Technical Information of China (English)
Xiao-Bing LI; Yun-Hao CHEN; Hua YANG; Yun-Xia ZHANG
2005-01-01
As one of the important vegetation parameters, vegetation fractional coverage (VFC) is more difficult to measure accurately among a good many parameters of plant communities. The temperate typical steppe in the north of China was chosen for investigation in the present study and a digital camera was used to measure herb community coverage in the field, adopting methods of ocular estimation, gridding measurement, visual interpretation, supervised classification, and information extraction of color spatial transformation to calculate the VFC of images captured by the digital camera. In addition VFC calculated by various methods was analyzed and compared VFC, enabling us to propose an effective method for measuring VFC using a digital camera. The results of the present study indicate that: (i) as two common useful and effective methods of measuring VFC with a digital camera, not only does the error of estimated values of visual estimation and supervised classification vary considerably, but the degree of automatization is very low and depends, to a great extent, on the manipulator; (ii) although the method of visual interpretation may assure the precision of the calculated VFC and enable the precision of results obtained using other methods to be determined, as far as large quantities of data are concerned, this method has the disadvantages of wasting time and energy, and the applications of this method are limited; (iii) the precision and stability of VFC calculated using the grid and node method are superior to those of visual estimation and supervised classification and inferior to those of visual interpretation, but, as for visual interpretation and supervised classification, gridding measurements are difficult to apply in practice because they are not time efficient;and (iv) in terms of the precision of calculation of the VFC, an information-extracting model based on an intensity, hue, saturation (IHS) color space-multi-component series segmentation strategy is
Energy Technology Data Exchange (ETDEWEB)
Shishkin, Yu.L. [Gubkin Russian State University of Oil and Gas, Leninsky Prospect 65, 119991 Moscow (Russian Federation)
2006-02-15
High-resolution differential scanning calorimetry was used to accurately establish the temperature intervals of oxidation/distillation of the major components of crude oils. Some theoretical aspects of the method of dynamic microdistillation, enabling consecutive distillation (oxidation) of the main components of hydrocarbon mixtures, are discussed. The experimental TG-DSC curves show that the temperature scan of the run can be divided into six regions, of which the first belongs to simple distillation of the sample's liquid constituent (the distillate) and the others to oxidative cracking distillation of the solid (heavy) residue. The latter occur in the order paraffins+light oils, middle base oils, heavy base oils, condensed aromatics (resins) and asphaltenes. The probable oxidation mechanisms of different classes of petroleum hydrocarbons operating in different temperature regions are discussed. Full quantitative fractional and group component analysis of a number of crude oils of different chemical classes and geological age was carried out by the combined TG-DSC techniques under specially chosen experimental conditions (those of dynamic microdistillation). (author)
Bahşı, Ayşe Kurt; Yalçınbaş, Salih
2016-01-01
In this study, the Fibonacci collocation method based on the Fibonacci polynomials are presented to solve for the fractional diffusion equations with variable coefficients. The fractional derivatives are described in the Caputo sense. This method is derived by expanding the approximate solution with Fibonacci polynomials. Using this method of the fractional derivative this equation can be reduced to a set of linear algebraic equations. Also, an error estimation algorithm which is based on the residual functions is presented for this method. The approximate solutions are improved by using this error estimation algorithm. If the exact solution of the problem is not known, the absolute error function of the problems can be approximately computed by using the Fibonacci polynomial solution. By using this error estimation function, we can find improved solutions which are more efficient than direct numerical solutions. Numerical examples, figures, tables are comparisons have been presented to show efficiency and usable of proposed method. PMID:27610294
Directory of Open Access Journals (Sweden)
Ana Paula Daniel
2006-12-01
Full Text Available O estudo teve por objetivo obter frações de farinha de aveia enriquecidas em amido e em fibras pelo fracionamento a seco e modificar quimicamente (fosfatação o amido da fração rica neste constituinte, avaliando suas propriedades funcionais. O fracionamento foi efetuado utilizando-se as granulometrias > 300, 212-300, 150-212, e 300 µm e 212-300 µm foram semelhantes, com aumento de aproximadamente 1,5 e 2,7 vezes nos teores de proteína e fibra, e redução de 0,5-0,6 vezes no teor de amido, quando comparadas à farinha integral. As frações 212-150 µm e The objective of this study was to obtain starch and fiber enriched oatmeal fractions through sieving, chemically modifying (phosphorylation the starch enriched fraction, and evaluating its functional properties. Fractionation was performed using > 300, 212-300, 150-212, and 300 µm and 212-300 µm were similar and had increased protein and fiber content (1.5 and 2.7 fold, but reduced starch content (0.5-0.6 fold when compared to whole oatmeal. Fractions 212-150 µm and < 150 µm were similar and had the highest starch content (around 70%. The starch-rich fraction < 150 µm that had the highest yield during sieving (35.5% was phosphorylated with sodium tripolyphosphate at 150-155 °C for 20 and 40 min, yielding 0.39 and 0.32% phosphorus bound, respectively. Cold water binding capacity increased (1.9-3.3 fold, while syneresis at 5 °C or after freezing/thawing was significantly reduced (6-20 and 5-6 fold, respectively in phosphorylated starch fraction when compared to the native starch fraction. Phosphorylation reduced the increase of pasta opacity during storage at 5 °C, which indicates a lower retrogradation tendency. Thus, oatmeal sieving yielded fractions either enriched in fiber and protein or enriched in starch. Moreover, phosphorylation of the starch-rich fraction improved their functional properties, which may increase the potential applicability and economic value of this
A convenient and efficient purification method for chemically labeled oligonucleotides.
Hwang, Jihee; Kang, Junhee; Kim, Seong Keun; Kim, Younggyu
2013-05-01
We developed an efficient, cost-effective, and rapid purification method for chemically-labeled oligonucleotides that requires less time than conventional procedures such as ethanol precipitation or size-exclusion chromatography. Based on the hydrophilic and hydrophobic properties of DNA and amine-reactive fluorophores, we show that n-butanol saturated with distilled water may be used to remove unreacted fluorophores by sequestering them in the organic phase, while labeled DNA remains in the aqueous phase. This phase extraction method is simple, fast, and allows for processing multiple samples simultaneously, a necessity for high-throughput labeling strategies. PMID:23662899
Hosana M. Debonsi; Rocha, Otávio P.; Rafael de Felício; Maria Claudia M. Young; Nair S. Yokoya; Sérgio de Albuquerque; Regina Maria B. Cicarelli; Daniela L Ambrósio; Rodrigues, Ana Helena B.
2011-01-01
The present study reports the Gas Chromatography-Mass Spectrometry (GC-MS) evaluation of the hexanes and dichloromethane fractions from extracts of the red alga Centroceras clavulatum (C. Agardh) Montagne. Twenty three compounds were identified, totaling ca. 42% of both fractions (0.18 g mass extract). The main constituents of the fractions were hexadecanoic acid (17.6%) and pentadecanoic acid (15.9%). Several secondary metabolites with interesting biological activity, such as (-)-loliolide, ...
Energy Technology Data Exchange (ETDEWEB)
J.C. van Dyk; L.L. Baxter; J.H.P. van Heerden; R.L.J. Coetzer [Sasol Technology, Sasolburg (South Africa). Syngas and Coal Technologies, R& amp; D Division
2005-10-01
Detailed coal and feedstock characteristics are essential to predict gasification performance when a specific coal source is to be gasified. One property that specifically gives detail information on the suitability of a coal source for gasification purposes is the ash fusion temperature (AFT). The AFT of a coal source indicates the extent to which ash agglomeration and ash clinkering are likely to occur within the gasifier. The principal aim of this paper is to obtain mineral species-specific information on ash properties and the specific affect on AFT. Chemical fractionation treatment resulted in coals having different mineral properties that can be used to explain the affect of specific minerals on the AFT of coal. The highest concentration and species of minerals were removed from the coal by acid leaching (HCl and HNO{sub 3}) where Al, Ca, Mg, Na and Fe were removed in high concentrations from the coal. The AFT of coal after leaching increased to {gt}1600{sup o}C. Based on the 95% confidence intervals depicted the following components can be highlighted as having a statistical significant effect on the AFT: Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, CaO, MgO, P{sub 2}O{sub 5} and SiO{sub 2}-Al{sub 2}O{sub 3} combination. When mineral ratio was used, the best correlation coefficient ) with AFT was obtained with the dolomite ratio. This is in agreement with the results obtained from the correlations between the AFT and the ash composition where CaO and MgO resulted in the best correlation with AFT. Results presented in this paper again highlights the fact and confirmed work from other researchers that ash composition (elemental analyses) on its own does not explain AFT behavior or commercial performance of coal accurately. 14 refs., 6 figs., 6 tabs.
International Nuclear Information System (INIS)
Microscopic structure in bubbly flows has been a topic of interest in the study of fluid dynamics. In the present paper, the ultrasonic Doppler method was applied to the measurement of bubbly. The experiments were carried out for an air-water dispersed bubbly flow in a 20 mm x 100 mm vertical rectangular channel having a void fraction smaller than 3%. Two ultrasonic transducers were installed on the outer surface of the test section with a contact angle of 45deg off the vertical axis, one facing upward and the other facing downward. By applying statistical methods to the two directional velocity profiles. Reynolds stress profiles were calculated. Furthermore, to clarify the wake effect induced by the leading bubbles, the velocity profiles were divided into two types of data. The first one is for all of the liquid data and the other is the data which did not include the wake effect. For Rem ≥ 1,593, it was observed that the bubbles suppressed the liquid turbulence. Furthermore, comparing with the Reynolds stress profiles in bubbly flow, it was found that Reynolds stress profiles varied with the amount of bubbles present in the flow and the effect of wake causes turbulence in the liquid. (author)
Wu, Fuke; Tian, Tianhai; Rawlings, James B; Yin, George
2016-05-01
The frequently used reduction technique is based on the chemical master equation for stochastic chemical kinetics with two-time scales, which yields the modified stochastic simulation algorithm (SSA). For the chemical reaction processes involving a large number of molecular species and reactions, the collection of slow reactions may still include a large number of molecular species and reactions. Consequently, the SSA is still computationally expensive. Because the chemical Langevin equations (CLEs) can effectively work for a large number of molecular species and reactions, this paper develops a reduction method based on the CLE by the stochastic averaging principle developed in the work of Khasminskii and Yin [SIAM J. Appl. Math. 56, 1766-1793 (1996); ibid. 56, 1794-1819 (1996)] to average out the fast-reacting variables. This reduction method leads to a limit averaging system, which is an approximation of the slow reactions. Because in the stochastic chemical kinetics, the CLE is seen as the approximation of the SSA, the limit averaging system can be treated as the approximation of the slow reactions. As an application, we examine the reduction of computation complexity for the gene regulatory networks with two-time scales driven by intrinsic noise. For linear and nonlinear protein production functions, the simulations show that the sample average (expectation) of the limit averaging system is close to that of the slow-reaction process based on the SSA. It demonstrates that the limit averaging system is an efficient approximation of the slow-reaction process in the sense of the weak convergence. PMID:27155630
International Nuclear Information System (INIS)
Fractional diffusion equations have been the focus of modeling problems in hydrology, biology, viscoelasticity, physics, engineering, and other areas of applications. In this paper, a meshfree method based on the moving Kriging interpolation is developed for a two-dimensional time-fractional diffusion equation. The shape function and its derivatives are obtained by the moving Kriging interpolation technique. For possessing the Kronecker delta property, this technique is very efficient in imposing the essential boundary conditions. The governing time-fractional diffusion equations are transformed into a standard weak formulation by the Galerkin method. It is then discretized into a meshfree system of time-dependent equations, which are solved by the standard central difference method. Numerical examples illustrating the applicability and effectiveness of the proposed method are presented and discussed in detail. (general)
Boszke, Leonard; Kowalski, Artur; Szczuciński, Witold; Rachlewicz, Grzegorz; Lorenc, Stanisław; Siepak, Jerzy
2006-12-01
The 26 December 2004 tsunami covered significant portion of a coastal zone with a blanket of potentially contaminated sediments. In this report are presented results on mercury concentrations in sediments deposited by the tsunami in a coastal zone of Thailand. Since the total mercury concentrations are insufficient to assess mercury mobility and bioavailability in sediment, its fractionation was applied. Sediments were sampled within 50 days after the event and analyzed by sequential extraction method. The procedure of sequential extraction involved five subsequent stages performed with solutions of chloroform, deionized water, 0.5 M HCl, 0.2 M NaOH, and aqua regia. The mean concentration of total mercury in sediments was 119 ± 50 ng g-1 dry mass (range 66-230). The fractionation revealed that mercury is mainly bound to the least bioavailable sulphides 75 ± 6% (range 62-86), organomercury compounds 14 ± 7% (range 4-26), and humic matter 9 ± 7% (range 1-27). The lowest contributions bring fractions of water-soluble mercury 0.8 ± 1.0% (range 0.1-3.6) and acid soluble mercury 0.9 ± 0.5% (range 0.2-2.1). Although, the total mercury content is similar in a reference sample and in the tsunami sediments, the highly toxic organomercury fraction contribution is higher in the latter. The results were compared with chemical and sedimentological properties of the sediments but no significant correlations were obtained between them.
Directory of Open Access Journals (Sweden)
Shaher Momani
2014-01-01
Full Text Available The multistep generalized differential transform method is applied to solve the fractional-order multiple chaotic FitzHugh-Nagumo (FHN neurons model. The algorithm is illustrated by studying the dynamics of three coupled chaotic FHN neurons equations with different gap junctions under external electrical stimulation. The fractional derivatives are described in the Caputo sense. Furthermore, we present figurative comparisons between the proposed scheme and the classical fourth-order Runge-Kutta method to demonstrate the accuracy and applicability of this method. The graphical results reveal that only few terms are required to deduce the approximate solutions which are found to be accurate and efficient.
Ariyaratne, Hiromi Wijesinghe; Asgautsen, Øyvind; Melaaen, Morten Christian; Eine, Kristin; Tokheim, Lars Andre
2012-01-01
Determination of net CO2 emissions from combustion of Refuse Derived Fuel (RDF) is not straight forward due to the heterogeneous nature of the fuel. The fossil fraction of the fuel is an essential parameter for the determination of net CO2 emissions. In the present study, the fossil fraction of RDF is determined by means of the Selective Dissolution Method (SDM) in calorific value basis. Seven artificially made RDF mixtures were tested using this method. The mixtures were prepa...
Zhou, Hao-Jun; Fan, Xiao-Qiang; Li, Zheng-Hong; Pu, Yi-Kang
2015-01-01
The perturbation method is proposed to obtain the effective delayed neutron fraction (\\b{eta}eff) of a cylindrical highly enriched uranium reactor. Based on the reactivity measurements with and without a sample at a designable position using the positive periodic technique, the reactor reactivity perturbation {\\Delta}\\r{ho} of the sample in \\b{eta}eff units is measured. The simulation of the perturbation experiments are performed by MCNP program. The PERT card is used to provide the difference dk of effective neutron multiplication factors with and without the sample inside the reactor. Based on the relationship between the effective multiplication factor and the reactivity, the equation \\b{eta}eff =dk/{\\Delta}\\r{ho} is derived. In this paper, the reactivity perturbations of 13 metal samples at the designable position of the reactor are measured and calculated. The average \\b{eta}eff value of the reactor is given as 0.00645, and the standard uncertainty is 3.0%. Additionally, the perturbation experiments for ...
Hao-Jun, Zhou; Yan-Peng, Yin; Xiao-Qiang, Fan; Zheng-Hong, Li; Yi-Kang, Pu
2016-06-01
A perturbation method is proposed to obtain the effective delayed neutron fraction β eff of a cylindrical highly enriched uranium reactor. Based on reactivity measurements with and without a sample at a specified position using the positive period technique, the reactor reactivity perturbation Δρ of the sample in β eff units is measured. Simulations of the perturbation experiments are performed using the MCNP program. The PERT card is used to provide the difference dk of effective neutron multiplication factors with and without the sample inside the reactor. Based on the relationship between the effective multiplication factor and the reactivity, the equation β eff = dk/Δρ is derived. In this paper, the reactivity perturbations of 13 metal samples at the designable position of the reactor are measured and calculated. The average β eff value of the reactor is given as 0.00645, and the standard uncertainty is 3.0%. Additionally, the perturbation experiments for β eff can be used to evaluate the reliabilities of the delayed neutron parameters. This work shows that the delayed neutron data of 235U and 238U from G.R. Keepin’s publication are more reliable than those from ENDF-B6.0, ENDF-B7.0, JENDL3.3 and CENDL2.2. Supported by Foundation of Key Laboratory of Neutron Physics, China Academy of Engineering Physics (2012AA01, 2014AA01), National Natural Science Foundation (11375158, 91326104)
International Nuclear Information System (INIS)
Objective: Longitudinal shortening is traditionally considered the predominant part of global right ventricular (RV) systolic function. Less attention has been paid to transverse contraction. The aim of this study was to evaluate RV transverse motion by cardiovascular magnetic resonance (CMR) in a large cohort of patients and to assess its relationship with RV ejection fraction (RVEF). Study design: We retrospectively analyzed the CMR scans of 300 patients referred to our center in 2010. RVEF was determined from short axis sequences using the volumetric method. Transverse parameters called RV fractional diameter changes were calculated after measuring RV diastolic and systolic diameters at basal and mid-level in short axis view (respectively FBDC and FMDC). We also measured the tricuspid annular plane systolic excursion (TAPSE) as a longitudinal reference. Results: Our population was divided into 2 groups according to RVEF. 250 patients had a preserved RVEF (>40%) and 50 had a RV dysfunction (RVEF ≤40%). Transverse and longitudinal motions were significantly reduced in the group with RV dysfunction (p < .0001). After ROC analysis, areas under the curve for FBDC, FMDC and TAPSE, were respectively 0.79, 0.82 and 0.72, with the highest specificity and sensitivity respectively of 88% and 68% for FMDC (threshold at 20%) for predicting RV dysfunction. FMDC had an excellent negative predictive value of 93%. Conclusion: RV fractional diameter changes, especially at the mid-level, appear to be accurate for semi-quantitative assessment of RV function by CMR. A cut-off of 20% for FMDC differentiates patients with a low (EF ≤ 40%) or a preserved RVEF
A novel in vitro method for the metabolism studies of radiotracers using mouse liver S9 fraction
Energy Technology Data Exchange (ETDEWEB)
Ryu, Eun Kyoung; Choi, Yearn Seong; Kim, Dong Hyun; Lee, Sang Yoon; Choi, Yong; Lee, Kyung Han; Kim, Byung Tae [School of Medicine, Sungkyunkwan Univ., Seoul (Korea, Republic of)
2004-08-01
Usefulness of mouse liver S9 fraction was evaluated for the measurement of the metabolites in the in vitro metabolism study of {sup 18}F-labeled radiotracers. Mouse liver S9 fraction was isolated at an early step in the course of microsome preparation. The in vitro metabolism studies were carried out by incubating a mixture containing the radiotracer, S9 fraction and NADPH at 37.deg.C, and an aliquot of the mixture was analyzed at the indicated time points by radio-TLC. Metabolic defluorination was further confirmed by the incubation with calcium phosphate, a bone mimic. The radiotracer [{sup 18}F]1 underwent metabolic defluorination within 15 min, which was consistent with the results of the in vivo method and the in vitro method using microsome. Radiotracer [{sup 18}F]2 was metabolized to three metabolites including 4-[{sup 18}F]fluorobenzoic acid within 60 min. It is likely that the one of these metabolites at the origin of radio-TLC was identical with the one that obtained from the in vivo and in vitro (microsome) method. Compared with the in vitro method using microsome, the method using S9 fraction gave a similar pattern of the metabolites but with a different ratio, which can be explained by the presence of cytosol in the S9 fraction. These results suggest that the findings of the in vitro metabolism studies using S9 fraction can reflect the in vitro metabolism of novel radiotracers in the liver. Moreover, this method can be used as a tool to determine metabolic defluorination along with calcium phosphate absorption method.
Indian Academy of Sciences (India)
M Matinfar; M Eslami; M Kordy
2015-10-01
This paper presents the exact solutions for the fractional Korteweg–de Vries equations and the coupled Korteweg–de Vries equations with time-fractional derivatives using the functional variable method. The fractional derivatives are described in the modified Riemann–Liouville derivative sense. It is demonstrated that the calculations involved in the functional variable method are extremely simple and straightforward and this method is very effective for handling nonlinear fractional equations.
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Hosana M. Debonsi
2011-08-01
Full Text Available The present study reports the Gas Chromatography-Mass Spectrometry (GC-MS evaluation of the hexanes and dichloromethane fractions from extracts of the red alga Centroceras clavulatum (C. Agardh Montagne. Twenty three compounds were identified, totaling ca. 42% of both fractions (0.18 g mass extract. The main constituents of the fractions were hexadecanoic acid (17.6% and pentadecanoic acid (15.9%. Several secondary metabolites with interesting biological activity, such as (--loliolide, neophytadiene, phytol were identified. In addition, several classes of secondary metabolites, including phenolic compounds (e.g., phenylacetic acid, terpene derivatives, fatty acids, halogenated compound (e.g., 2-chlorocyclohexenol, lignoids, steroids, esters, amides (e.g., hexadecanamide, ketones, carboxylic acids, aldehydes and alcohols were observed. The occurrence of several of these structural classes is described for the first time in this species. The same fractions analyzed by GC-MS, and a separate set of polar fractions, were evaluated against two life cycle stages (epimastigote and trypomastigote forms of the protozoan Trypanosoma cruzi and against phytopatogenic fungi Cladosporium cladosporiodes and C. sphaerospermum. The dichloromethane fraction was active against both T. cruzi forms (epimastigote IC50 = 19.1 μg.mL−1 and trypomastigote IC50 = 76.2 μg.mL−1. The hexanes and ethyl acetate fractions also displayed activity against both fungi species (200 μg by TLC-bioautography.
Larsen, K K; Wielandt, D; Schiller, M; Bizzarro, M
2016-04-22
Chromatographic purification of chromium (Cr), which is required for high-precision isotope analysis, is complicated by the presence of multiple Cr-species with different effective charges in the acid digested sample aliquots. The differing ion exchange selectivity and sluggish reaction rates of these species can result in incomplete Cr recovery during chromatographic purification. Because of large mass-dependent inter-species isotope fractionation, incomplete recovery can affect the accuracy of high-precision Cr isotope analysis. Here, we demonstrate widely differing cation distribution coefficients of Cr(III)-species (Cr(3+), CrCl(2+) and CrCl2(+)) with equilibrium mass-dependent isotope fractionation spanning a range of ∼1‰/amu and consistent with theory. The heaviest isotopes partition into Cr(3+), intermediates in CrCl(2+) and the lightest in CrCl2(+)/CrCl3°. Thus, for a typical reported loss of ∼25% Cr (in the form of Cr(3+)) through chromatographic purification, this translates into 185ppm/amu offset in the stable Cr isotope ratio of the residual sample. Depending on the validity of the mass-bias correction during isotope analysis, this further results in artificial mass-independent effects in the mass-bias corrected (53)Cr/(52)Cr (μ(53)Cr* of 5.2ppm) and (54)Cr/(52)Cr (μ(54)Cr* of 13.5ppm) components used to infer chronometric and nucleosynthetic information in meteorites. To mitigate these fractionation effects, we developed strategic chemical sample pre-treatment procedures that ensure high and reproducible Cr recovery. This is achieved either through 1) effective promotion of Cr(3+) by >5 days exposure to HNO3H2O2 solutions at room temperature, resulting in >∼98% Cr recovery for most types of sample matrices tested using a cationic chromatographic retention strategy, or 2) formation of Cr(III)-Cl complexes through exposure to concentrated HCl at high temperature (>120°C) for several hours, resulting in >97.5% Cr recovery using a
Use of ab initio quantum chemical methods in battery technology
Energy Technology Data Exchange (ETDEWEB)
Deiss, E. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-06-01
Ab initio quantum chemistry can nowadays predict physical and chemical properties of molecules and solids. An attempt should be made to use this tool more widely for predicting technologically favourable materials. To demonstrate the use of ab initio quantum chemistry in battery technology, the theoretical energy density (energy per volume of active electrode material) and specific energy (energy per mass of active electrode material) of a rechargeable lithium-ion battery consisting of a graphite electrode and a nickel oxide electrode has been calculated with this method. (author) 1 fig., 1 tab., 7 refs.
Mozaffari Khalf Badam, A.; Pichler, T.
2014-12-01
Mobilization of naturally occurring molybdenum (Mo) and arsenic (As) in sedimentary rocks, mainly carbonates, contaminate groundwater in the Lithia area. The sedimentary rocks contains up to 825 mg kg-1 Mo and 144 mg kg-1 As. Mo and As groundwater concentrations reached up to 5000 μg L-1 and 300 μg L-1 and exceed the WHO guidelines of 70 and 10 μg L-1, respectively. In order to asses their fractions and origins, a modified five-step (adsorbed/exchangeable, carbonates, hydrous iron oxides, crystalline iron oxides, sulfides and organic matter (OM)) sequential extraction procedure (SEP) was applied to 10 samples. Determination of the elements was carried out by ICP-MS. The SEP results were compared to values obtained by total digestion with aqua regia. The recovery ranged from 88 to 111 % for Mo and 75 to 116 % for As and RSD was better than 10%. In most samples up to 90 % of the Mo was present in the adsorbed/exchangeable fraction (step 1), characterizing a major Mo source. Pyrite, which is present in the aquifer matrix beneath Lithia, is generally considered a source for Mo. Electron microprobe analysis, did not confirm the presence of Mo in pyrite. Thus oxidation of OM is the main reason for the high Mo content in step 1 and groundwater. Another possible source for Mo in groundwater could be the mineral powellite (CaMoO4). To investigate this possibility powellite saturation was calculated with PHREEQC under alkaline conditions. Powellite was super saturated once Mo concentrations exceeded 3000 μg L-1. Thus powellite was not considered a source, but rather a sink for Mo released form OM. In contrast to Mo, As was present in each extraction step in somewhat similar abundance: step 1 (17%), step 2 (11% ), step 3 (30 %), step 4 (23 %) and step 5 (18%). Hydrous and crystalline iron oxides which were dissolved in step 3 and 4 contained the highest As concentrations. Electron microprobe analysis of pyrite, which was dissolved in step 5, showed concentrations of up to
International Nuclear Information System (INIS)
Four ewes were given two diets made up with two ratios of rolled barley grain and ammonia treated straw (80/20, diet C and 20/80, diet R). The animals were fed twice a day. Two microbial markers, purine bases (PB) and 15N, were used as internal and external markers, respectively. Ruminal bacteria from the liquid (LAB) and solid (SAB) fractions of digesta were harvested from samples obtained at 1 and 6 h after feeding. Bacteria were separated from the particulate material by cooling plus homogenisation (B), by applying tertiary butanol (TB) or methylcellulose (M), or by changes of temperature (CHT). The most effective procedures to remove bacteria from the solid phase were M and CHT treatments. CHT, however, showed the highest level of losses and the lowest total recovery of the bacterial pellet. There were no differences between B and TB treatments in either detaching efficiency or total recovery ratio of adherent bacteria. Ratio of recovery of detached material as a bacterial pellet was 32.0, 32.2, 33.3 and 27.8% for B, TB, M and CHT treatments, respectively. Diet did not interact with detaching efficiency of the experimental treatments although concentration of total N (g/100g OM) and PB (μmol/g OM) were higher in pellets obtained with diet C (9.11 and 125) than with diet R (8.20 and 107), respectively (P < 0.05). Postpandrial differences were not significant. Bacterial samples extracted from the liquid phase contained significantly (P < 0.001) more total N (9.21 vs 8.51), PB (160.5 vs 104.3) and PB/N (1.73 vs 1.23 μmol/mg) than those samples extracted from the solid phase. There were no differences in the chemical composition of the microbial sample after detachment by B, TB and M treatments but the bacterial extract obtained after CHT treatment showed significant changes in PB, N content and PB/N ratio (P < 0.01). (author)
Directory of Open Access Journals (Sweden)
Vercier P.
2006-11-01
Full Text Available Après avoir défini les termes fractions lourdes et pétroles bruts lourds, et avoir souligné l'intérêt économique qu'il y a à utiliser ces matériaux, on passera en revue les techniques analytiques disponibles pour aborder les difficiles problèmes technologiques que soulève l'emploi des équipements et des méthodes conventionnels. On montrera que les analystes auront besoin de techniques améliorées ou même entièrement nouvelles pour séparer ces produits en des fractions plus simples, susceptibles d'être alors analysées par les méthodes plus traditionnelles : distillation à haute température (jusqu'à 650 °C ; séparation en asphaltènes, résines et huile ; séparation en acides, bases, neutres, saturés, mono-, di-, poly-aromatiques ; analyses structurales (analyses élémentaires, détermination des masses moléculaires, spectrométrie de masse, RMN, pyrolyse et détection à l'aide de détecteurs spécifiques pour le soufre et l'azote. Comme le facteur temps est important dans les études pilote, il sera montré que la mise au point des méthodes rapides et modernes de chromatographie liquide sera l'objectif prioritaire de la recherche analytique dans le futur proche. After defining the terms heavy fractionsand heavy crudesand then stressing the economic interest there is in using such materials, a survey is made of the analytical techniques available for tackling the difficult technological problems arising from the use of conventional equipment and methods. It is shown that analysts will need improved or even completely new techniques for separating such products into simpler fractions so that they can be analyzed by more traditional methods, i. e. high-temperature distillation (up to 650°C; separation into asphaltenes, resins and oils; structural analyses (elemental analyses, determining molecular weights, mass spectrometry, NMR, pyrolysis and detection with specific sulfur and nitrogen detectors. Since the time
Faksness, Liv-Guri; Altin, Dag; Nordtug, Trond; Daling, Per S; Hansen, Bjørn Henrik
2015-02-15
Two Source oils and five field collected oil residues from the Deepwater Horizon incident were chemically characterized. Water accommodated fractions (WAFs) of the Source oils and two of the field-weathered oils were prepared to evaluate the impact of natural weathering on the chemical composition and the acute toxicity of the WAFs. Toxicity test species representing different tropic levels were used (the primary producer Skeletonema costatum (algae) and the herbivorous copepod Acartia tonsa). The results suggest that the potential for acute toxicity is higher in WAFs from non-weathered oils than WAFs from the field weathered oils. The Source oils contained a large fraction of soluble and bioavailable components (such as BTEX (benzene, toluene, ethyl benzene, xylenes) and naphthalene), whereas in the surface collected oils these components were depleted by dissolution into the water column as the oil rose to the surface and by evaporative loss after reaching the sea surface. PMID:25534626
Chemical methods for the determination of composition of cryolite
International Nuclear Information System (INIS)
Preparation of uranium and plutonium alloys containing aluminium involves the use of cryolite and many times, cryolite which may be contaminated with alpha activity has to be analysed for its purity. In view of this, chemical methods for the determination of composition of commercial cryolite samples have been developed. Methods are standardised for the determination of individual constituents of cryolite viz., aluminium, sodium, fluoride and major impurities, calcium and magnesium. Studies on the dissolution of the sample, effect of one or more components on the determination of the other and their elimination are carried out. Aluminium and sodium are determined gravimetrically as oxinate and triple acetate respectively. Fluoride is determined by a volumetric procedure after cation exchange separtion of soluble fluoride. Calcium and magnesium are determined by a sequential pH-metri titration. This report describes the details of the procedures and the results of these studies for two commercial cryolite samples. (author). 7 tabs
International Nuclear Information System (INIS)
The straight-run gasoline fraction (boiling range _ IBP-220℃) of Taribani oil (East Georgia) has been studied on modern instrumental level. The main physico-chemical characteristics (group hydrocarbon composition, density, average molecular weight, vapour pressure, research octane number, etc) are ascertained. The fraction composition of straight-run gasoline (with the accuracy of 1 wt. %) is determined by the method of gas-liquid chromatography. (authors)
On the no-field method for void time determination in flow field-flow fractionation.
Martin, Michel; Hoyos, Mauricio
2011-07-01
Elution time measurements of colloidal particles injected in a symmetrical flow field-flow fractionation (flow FFF) system when the inlet and outlet cross-flow connections are closed have been performed. This no-field method has been proposed earlier for void time (and void volume) determination in flow FFF Giddings et al. (1977). The elution times observed were much larger than expected on the basis of the channel geometrical volume and the flow rate. In order to explain these discrepancies, a flow model allowing the carrier liquid to flow through the porous walls toward the reservoirs located behind the porous elements and along these reservoirs was developed. The ratio between the observed elution time and expected one is found to depend only on a parameter which is a function of the effective permeability and thickness of the porous elements and of the channel thickness and length. The permeabilities of the frits used in the system were measured. Their values lead to predicted elution times in reasonable agreement with experimental ones, taking into account likely membrane protrusion inside the channel on system assembly. They comfort the basic feature of the flow model, in the no-field case. The carrier liquid mostly bypasses the channel to flow along the system mainly in the reservoir. It flows through the porous walls toward the reservoirs near channel inlet and again through the porous walls from the reservoirs to the channel near channel outlet before exiting the system. In order to estimate the extent of this bypassing process, it is desirable that the hydrodynamic characteristics of the permeable elements (permeability and thickness) are provided by flow FFF manufacturers. The model applies to symmetrical as well as asymmetrical flow FFF systems. PMID:21256498
soil organic matter fractionation
Osat, Maryam; Heidari, Ahmad
2010-05-01
Carbon is essential for plant growth, due to its effects on other soil properties like aggregation. Knowledge of dynamics of organic matter in different locations in the soil matrix can provide valuable information which affects carbon sequestration and soil the other soil properties. Extraction of soil organic matter (SOM) fractions has been a long standing approach to elucidating the roles of soil organic matter in soil processes. Several kind fractionation methods are used and all provide information on soil organic matter function. Physical fractionation capture the effects on SOM dynamics of the spatial arrangement of primary and secondary organomineral particles in soil while chemical fractionation can not consider the spatial arrangement but their organic fractions are suitable for advanced chemical characterization. Three method of physical separation of soil have been used, sieving, sedimentation and densitometry. The distribution of organic matter within physical fractions of the soil can be assessed by sieving. Sieving separates soil particles based strictly on size. The study area is located on north central Iran, between 35° 41'- 36° 01' N and 50° 42'- 51° 14' E. Mean annual precipitation about 243.8 mm and mean annual air temperature is about 14.95 °C. The soil moisture and temperature regime vary between aridic-thermic in lower altitudes to xeric-mesic in upper altitudes. More than 36 surface soil samples (0-20 cm) were collected according to land-use map units. After preliminary analyzing of samples 10 samples were selected for further analyses in five size fractions and three different time intervals in September, January and April 2008. Fractionation carried out by dry sieving in five classes, 1-2 mm, 0.5-1 mm, 270 μm-0.5mm, 53-270 μm and soil organic matter to humic acid and fulvic acid shows that there is a better correlation between humic acid contents and soil organic matter (R2 = 0.86) than fulvic acid and organic matter (R2=0.5). The
A New Method to Constrain Supernova Fractions Using X-ray Observations of Clusters of Galaxies
Bulbul, Esra; Smith, Randall K.; Loewenstein, Michael
2012-01-01
Supernova (SN) explosions enrich the intracluster medium (ICM) both by creating and dispersing metals. We introduce a method to measure the number of SNe and relative contribution of Type Ia supernovae (SNe Ia) and core-collapse supernovae (SNe cc) by directly fitting X-ray spectral observations. The method has been implemented as an XSPEC model called snapec. snapec utilizes a single-temperature thermal plasma code (apec) to model the spectral emission based on metal abundances calculated using the latest SN yields from SN Ia and SN cc explosion models. This approach provides a self-consistent single set of uncertainties on the total number of SN explosions and relative fraction of SN types in the ICM over the cluster lifetime by directly allowing these parameters to be determined by SN yields provided by simulations. We apply our approach to XMM-Newton European Photon Imaging Camera (EPIC), Reflection Grating Spectrometer (RGS), and 200 ks simulated Astro-H observations of a cooling flow cluster, A3112.We find that various sets of SN yields present in the literature produce an acceptable fit to the EPIC and RGS spectra of A3112. We infer that 30.3% plus or minus 5.4% to 37.1% plus or minus 7.1% of the total SN explosions are SNe Ia, and the total number of SN explosions required to create the observed metals is in the range of (1.06 plus or minus 0.34) x 10(exp 9), to (1.28 plus or minus 0.43) x 10(exp 9), fromsnapec fits to RGS spectra. These values may be compared to the enrichment expected based on well-established empirically measured SN rates per star formed. The proportions of SNe Ia and SNe cc inferred to have enriched the ICM in the inner 52 kiloparsecs of A3112 is consistent with these specific rates, if one applies a correction for the metals locked up in stars. At the same time, the inferred level of SN enrichment corresponds to a star-to-gas mass ratio that is several times greater than the 10% estimated globally for clusters in the A3112 mass range.
Vincenzo, Fiorenzo; Matteucci, Francesca; Spitoni, Emanuele
2016-01-01
In this Letter, we present a new theoretical method for solving the chemical evolution of galaxies, by assuming the instantaneous recycling approximation for chemical elements restored by massive stars and the Delay Time Distribution formalism for the delayed chemical enrichment by Type Ia Supernovae. The galaxy gas mass assembly history, together with the assumed stellar yields and initial mass function, represent the starting point of this method. We derive a very simple and general equatio...
U-Pb dating by zircon dissolution method using chemical abrasion
Energy Technology Data Exchange (ETDEWEB)
Takehara, Lucy, E-mail: lucytakehara@gmail.com.br [Servico Geologico do Brasil (CPRM), Brasilia, DF (Brazil); Chemale Junior, Farid [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia; Hartmann, Leo A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Dussin, Ivo A.; Kawashita, Koji [Universidade de Sao Paulo (USP), SP, (Brazil). Centro de Pesquisa Geocronologicas
2012-06-15
Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using {sup 235}U-{sup 205}Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)
U-Pb dating by zircon dissolution method using chemical abrasion
International Nuclear Information System (INIS)
Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)
Protein fraction heterogeneity in donkey’s milk analysed by proteomic methods
Directory of Open Access Journals (Sweden)
G. D'Urso
2010-04-01
Full Text Available Donkey’s milk is often well tolerate by patients affected by cow’s milk protein allergy, probably thanks to its protein composition. This empiric evidence, confirmed by some clinical trials, needs to be better investigated. A preliminary survey on the protein fraction of donkey’s milk was carried out: fifty-six individual milk samples have been collected and analysed by IEF and SDS-PAGE. Five different IEF patterns have been identified, showing a marked heterogeneity both in casein and whey protein fractions. A single IEF pattern showed an apparent reduced amount of casein fraction highlighted by SDS. Three of the five IEF patterns have been further investigated by Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS.
Method of waste stabilization with dewatered chemically bonded phosphate ceramics
Wagh, Arun; Maloney, Martin D.
2010-06-29
A method of stabilizing a waste in a chemically bonded phosphate ceramic (CBPC). The method consists of preparing a slurry including the waste, water, an oxide binder, and a phosphate binder. The slurry is then allowed to cure to a solid, hydrated CBPC matrix. Next, bound water within the solid, hydrated CBPC matrix is removed. Typically, the bound water is removed by applying heat to the cured CBPC matrix. Preferably, the quantity of heat applied to the cured CBPC matrix is sufficient to drive off water bound within the hydrated CBPC matrix, but not to volatalize other non-water components of the matrix, such as metals and radioactive components. Typically, a temperature range of between 100.degree. C.-200.degree. C. will be sufficient. In another embodiment of the invention wherein the waste and water have been mixed prior to the preparation of the slurry, a select amount of water may be evaporated from the waste and water mixture prior to preparation of the slurry. Another aspect of the invention is a direct anyhydrous CBPC fabrication method wherein water is removed from the slurry by heating and mixing the slurry while allowing the slurry to cure. Additional aspects of the invention are ceramic matrix waste forms prepared by the methods disclosed above.
Cai, Andong; Xu, Hu; Shao, Xingfang; Zhu, Ping; Zhang, Wenju; Xu, Minggang; Murphy, Daniel V
2016-01-01
Long-term manure application is recognized as an efficient management practice to enhance soil organic carbon (SOC) accumulation and nitrogen (N) mineralization capacity. A field study was established in 1979 to understand the impact of long-term manure and/or chemical fertilizer application on soil fertility in a continuous maize cropping system. Soil samples were collected from field plots in 2012 from 9 fertilization treatments (M0CK, M0N, M0NPK, M30CK, M30N, M30NPK, M60CK, M60N, and M60NPK) where M0, M30, and M60 refer to manure applied at rates of 0, 30, and 60 t ha-1 yr-1, respectively; CK indicates no fertilizer; N and NPK refer to chemical fertilizer in the forms of either N or N plus phosphorus (P) and potassium (K). Soils were separated into three particle-size fractions (2000-250, 250-53, and fractions was used to evaluate the effect of long-term manure, in combination with/without chemical fertilization application, on the accumulation and mineralization of SOC and total N in each fraction. Results showed that long-term manure application significantly increased SOC and total N content and enhanced C and N mineralization in the three particle-size fractions. The content of SOC and total N followed the order 2000-250 μm > 250-53μm > 53 μm fraction, whereas the amount of C and N mineralization followed the reverse order. In the fraction, the M60NPK treatment significantly increased the amount of C and N mineralized (7.0 and 10.1 times, respectively) compared to the M0CK treatment. Long-term manure application, especially when combined with chemical fertilizers, resulted in increased soil microbial biomass C and N, and a decreased microbial metabolic quotient. Consequently, long-term manure fertilization was beneficial to both soil C and N turnover and microbial activity, and had significant effect on the microbial metabolic quotient. PMID:27031697
Gangloff, Sophie; Stille, Peter; Schmitt, Anne-Désirée; Chabaux, François
2016-09-01
The objectives of this study were to determine the processes and physico-chemical conditions that affect the composition of the soil solutions of a forest soil and to elucidate their impact on the transport of major and trace elements through the colloidal (0.2 μm to 5 kDa) and dissolved (soil. All experiments were performed with soil solutions obtained using lysimeter plates situated on an experimental spruce parcel of the Strengbach catchment (Northeastern France). The surface samples filtered at 0.2 μm facilitated the examination of the influence of litter decomposition on the chemical composition of the upper soil solutions. The impact of the soils biogeochemical conditions (pH, moisture, temperature, oxic or anoxic conditions) on litter decomposition was also examined. More particularly, the increase in NH4+ and NO2- compounds in some of the soil solutions points to denitrification processes in an anoxic environment. Thus, under anoxic conditions, the soil solution is enriched in Ca, P, Mn and Zn, whereas under oxic conditions it is enriched in Al and Fe. The physico-chemical conditions are more seasonally dependent in the upper soil horizons than in the deeper ones and have an impact on the variability of the chemical composition of the soil solutions. The colloidal and dissolved fractions of the soil solutions were obtained by tangential flow ultra-filtration. The experimental results reveal that nutrients, such as NO3- and P, are primarily in the dissolved fraction and consequently bioavailable; secondary minerals may be dissolved and/or precipitate in the colloidal fraction, such as pyromorphite (Pb5(PO4)3(OH, Cl, F)). The results further indicate that microbial activity influences the composition of the colloidal and dissolved fractions, and possibly enriches the colloidal fraction in Ca, Mn and P, diminishes the concentrations of Pb, V, Cr and Fe in the dissolved fraction, and changes the structure of organic carbon (OC). These results are important
Analysing chaos in fractional-order systems with the harmonic balance method
Institute of Scientific and Technical Information of China (English)
Wu Zheng-Mao; Lu Jun-Guo; Xie Jian-Ying
2006-01-01
In this paper, the fractional-order Genesio-Tesi system showing chaotic behaviours is introduced, and the corresponding one in an integer-order form is studied intensively. Based on the harmonic balance principle, which is widely used in the frequency analysis of nonlinear control systems, a theoretical approach is used to investigate the conditions of system parameters under which this fractional-order system can give rise to a chaotic attractor. Finally, the numerical simulation is used to verify the validity of the theoretical results.
Quantum confinement of lead titanate nanocrystals by wet chemical method
Energy Technology Data Exchange (ETDEWEB)
Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)
2015-11-15
Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.
Quantum confinement of lead titanate nanocrystals by wet chemical method
International Nuclear Information System (INIS)
Lead Titanate (PbTiO3) is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO3 nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO3 nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO3 nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO3 fabricated by wet chemical method. • PbTiO3 NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm
Energy Technology Data Exchange (ETDEWEB)
Vriesmann, Lucia C.; Silveira, Joana L.M. [Universidade Federal do Parana, Departamento de Bioquimica e Biologia Molecular, CP 19046, CEP 81531-990, Curitiba-PR (Brazil); Petkowicz, Carmen L. de O [Universidade Federal do Parana, Departamento de Bioquimica e Biologia Molecular, CP 19046, CEP 81531-990, Curitiba-PR (Brazil)], E-mail: clop@ufpr.br
2009-03-01
The pulp obtained from the fruit of cupuassu (Theobroma grandiflorum) was extracted with hot aqueous 0.1% citric acid to give fraction 0.1CA-2 in 15% yield. This was the predominant component polysaccharide, 91% of which was composed of starch, by an iodine test and monosaccharide composition, and its {sup 13}C NMR spectrum was consistent with that of a high amylose starch. The content of amylose found in fraction 0.1CA-2 was 71%. This value is higher than those of common starches of cereal grains, tubers, roots, and other fruits. The fraction was submitted to rheological examination, gels being prepared on heating with concentrations of 4 to 7% (w/w). A non-Newtonian behavior was observed, and gel viscosity and strength depended on the concentration. The presence of starch, as well as the presence of previously investigated pectin, conferred the high viscosity and gelling capability of the pulp.
International Nuclear Information System (INIS)
The pulp obtained from the fruit of cupuassu (Theobroma grandiflorum) was extracted with hot aqueous 0.1% citric acid to give fraction 0.1CA-2 in 15% yield. This was the predominant component polysaccharide, 91% of which was composed of starch, by an iodine test and monosaccharide composition, and its 13C NMR spectrum was consistent with that of a high amylose starch. The content of amylose found in fraction 0.1CA-2 was 71%. This value is higher than those of common starches of cereal grains, tubers, roots, and other fruits. The fraction was submitted to rheological examination, gels being prepared on heating with concentrations of 4 to 7% (w/w). A non-Newtonian behavior was observed, and gel viscosity and strength depended on the concentration. The presence of starch, as well as the presence of previously investigated pectin, conferred the high viscosity and gelling capability of the pulp
Institute of Scientific and Technical Information of China (English)
Xiao Rong HU; Hui LI; Yong Xiang ZHANG
2004-01-01
Most of the mercury and selenium exist in the insoluble fraction of dolphin liver. After the insoluble fraction was digested by alkaline protease in the presence of 1%SDS, approximately 50% of Hg and Se consisted in the supernatant and the others in the residue. Gel filtration chromatography of the hydrolysate showed that 96% of Hg and 87% of Se were combined with the high molecular weight proteins stably, which cannot be substituted by the complex reagents. Mercury and selenium in the residue were confirmed as HgSe crystal.
Rout, Soumya P; Kar, Durga M
2014-01-01
GC-MS analysis of fractions prepared from hydro-alcoholic extract of Annona reticulata Linn (Family Annonaceae) leaf revealed the presence of 9,10-dimethyltricyclo[4.2.1.1(2,5)]decane-9,10-diol; 4-(1,5-dihydroxy-2,6,6-trimethylcyclohex-2-enyl)but-3-en-2-one; 3,7-dimethyl-6-nonen-1-ol acetate; 9-octadecenamide,(Z)-; glycerine; D-glucose,6-O-α-D-galactopyranosyl-; desulphosinigrin and α-methyl-D-mannopyranoside as few of the major compounds in different fractions. The presence of these compounds in the plant has been identified for the first time. PMID:25050939
Ali, Iftikhar; Chanane, Bilal; Malik, Nadeem A.
2014-01-01
We consider a time fractional differential equation of order $\\alpha$, $0 0, \\quad c(x,0)=f(x). $$ where ${}^C_0\\mathcal{D}_t^{\\alpha}$ is the Caputo fractional derivative of order $\\alpha$, $A$ is a linear differential operator, $q(x,t)$ is a source term, and $f(x)$ is the inital condition. Approximate (truncated) series solutions are obtained by means of the Variational Iteration Method (VIM). We find the series solutions for different cases of the source term, in a form that is readily imp...
Velali, Ekaterini; Papachristou, Eleni; Pantazaki, Anastasia; Choli-Papadopoulou, Theodora; Planou, Styliani; Kouras, Athanasios; Manoli, Evangelia; Besis, Athanasios; Voutsa, Dimitra; Samara, Constantini
2016-01-01
Chemical and toxicological characterization of the water-soluble fraction of size-segregated urban particulate matter (PM) (7.2 μm) was carried out at two urban sites, traffic and urban background, during the cold and the warm period. Chemical analysis of the water-soluble PM fraction included ionic species (NO3(-), SO4(2-), Cl(-), Na(+), NH4(+), K(+), Mg(2+), Ca(2+)), water-soluble organic carbon (WSOC), and trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Pb, Mn, Ni, Zn, Pt, Pd, Rh, Ru, Ir, Ca, and Mg). The dithiothreitol (DTT) assay was employed for the abiotic assessment of the oxidative PM activity. Cytotoxic responses were investigated in vitro by applying the mitochondrial dehydrogenase (MTT) and the lactate dehydrogenase (LDH) bioassays on human lung cells (MRC-5), while DNA damage was estimated by the single cell gel electrophoresis assay, known as Comet assay. The correlations between the observed bioactivity responses and the concentrations of water-soluble chemical PM constituents in the various size ranges were investigated. The results of the current study corroborate that short-term bioassays using lung human cells and abiotic assays, such as the DTT assay, could be relevant to complete the routine chemical analysis and to obtain a preliminary screening of the potential effects of PM-associated airborne pollutants on human health. PMID:26586634
ZnSe thin films by chemical bath deposition method
Energy Technology Data Exchange (ETDEWEB)
Lokhande, C.D.; Patil, P.S.; Tributsch, H. [Hahn-Meitner-Institute, Bereich Physikalische Chemie, Abt. CS, Glienicker Strasse-100, D-14109 Berlin (Germany); Ennaoui, A. [Hahn-Meitner-Institute, Bereich Physikalische Chemie, Abt. CG, Glienicker Strasse-100, D-14109 Berlin (Germany)
1998-09-04
The ZnSe thin films have been deposited onto glass substrates by the simple chemical bath deposition method using selenourea as a selenide ion source from an aqueous alkaline medium. The effect of Zn ion concentration, bath temperature and deposition time period on the quality and thickness of ZnSe films has been studied. The ZnSe films have been characterized by XRD, TEM, EDAX, TRMC (time-resolved microwave conductivity), optical absorbance and RBS techniques for their structural, compositional, electronic and optical properties. The as-deposited ZnSe films are found to be amorphous, Zn rich with optical band gap, Eg, equal to 2.9 eV
New method of plant mitochondria isolation and sub-fractionation for proteomic analyses
Czech Academy of Sciences Publication Activity Database
Hájek, Tomáš; Honys, David; Čapková, Věra
2004-01-01
Roč. 167, č. 3 (2004), s. 389-395. ISSN 0168-9452 R&D Projects: GA MŠk LZ1K03018 Institutional research plan: CEZ:AV0Z5038910 Keywords : plant mitochondria isolation * sub-fractionation * protein analysis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.389, year: 2004
Foam Fractionation of Lycopene: An Undergraduate Chemistry Experiment
Wang, Yan; Zhang, Mingjie; Hu, Yongliang
2010-01-01
A novel experiment for the extraction of lycopene from tomato paste by foam fractionation is described. Foam fractionation is a process for separating and concentrating chemicals by utilizing differences in their surface activities. Extraction of lycopene by foam fractionation is a new method that has not been previously reported in the…
Convolution method and CTV-to-PTV margins for finite fractions and small systematic errors
Gordon, J. J.; Siebers, J. V.
2007-04-01
The van Herk margin formula (VHMF) relies on the accuracy of the convolution method (CM) to determine clinical target volume (CTV) to planning target volume (PTV) margins. This work (1) evaluates the accuracy of the CM and VHMF as a function of the number of fractions N and other parameters, and (2) proposes an alternative margin algorithm which ensures target coverage for a wider range of parameter values. Dose coverage was evaluated for a spherical target with uniform margin, using the same simplified dose model and CTV coverage criterion as were used in development of the VHMF. Systematic and random setup errors were assumed to be normally distributed with standard deviations Σ and σ. For clinically relevant combinations of σ, Σ and N, margins were determined by requiring that 90% of treatment course simulations have a CTV minimum dose greater than or equal to the static PTV minimum dose. Simulation results were compared with the VHMF and the alternative margin algorithm. The CM and VHMF were found to be accurate for parameter values satisfying the approximate criterion: σ[1 - γN/25] 0.2, because they failed to account for the non-negligible dose variability associated with random setup errors. These criteria are applicable when σ gap σP, where σP = 0.32 cm is the standard deviation of the normal dose penumbra. (Qualitative behaviour of the CM and VHMF will remain the same, though the criteria might vary if σP takes values other than 0.32 cm.) When σ Lt σP, dose variability due to random setup errors becomes negligible, and the CM and VHMF are valid regardless of the values of Σ and N. When σ gap σP, consistent with the above criteria, it was found that the VHMF can underestimate margins for large σ, small Σ and small N. A potential consequence of this underestimate is that the CTV minimum dose can fall below its planned value in more than the prescribed 10% of treatments. The proposed alternative margin algorithm provides better margin
Institute of Scientific and Technical Information of China (English)
LI Yong-qiang; ZHU Ren-jun; TIAN Ji-chun
2008-01-01
A strong gluten wheat cultivar Shannong 12 and a medium-strength wheat cultivar Shannong 11 were used to investigate the effects of wheat protein contents and protein fractions on dough rheological properties using a reconstitution method. The results indicated that the peak height, peak width, peak integral, resistance to extension and area under the curve were increased when protein content increased to 120, 140, and 160% (w/w) of the protein content in the base flours for doughs made from each wheat cultivar. All protein fractions were added to each of the base flours at three levels (0.25, 0.50 and 1.00%, w/w) based upon the protein content. The mixograph dough development time, peak width, and resistance to extension increased when the glutenin, insoluble glutenin, soluble glutenin, and glutenin macropolymer were added and increased systematically with increasing levels of these fractions. Peak integral increased by adding and increasing protein content, however, albumin-globulin had no obvious effects. Extensibility at rupture decreased when the glutenin, insoluble glutenin, soluble glutenin, and glutenin macropolymer were added, and decreased systematically with increasing levels of these fractions. However, extensibility at rupture increased when the monomeric protein, albumin-globulin, and gliadin were added, and increased systematically with increasing levels of these fractions.
Jafari, Mousa; Rajabzadeh, Amin Reza; Tabtabaei, Solmaz; Marsolais, Frédéric; Legge, Raymond L
2016-10-01
A solvent-free electrostatic separation method was employed to separate navy bean flour (NBF) into protein-rich (PR) and starch-rich (SR) fractions. The physicochemical properties of NBF and separated fractions were compared to proteins (navy bean isolate (NBI) and 7S globulin) prepared using a wet process. Gel electrophoresis confirmed that the protein distribution in the isolated fractions was similar to that of NBF. The protein profile of NBI and 7S globulin was found to be devoid of certain proteins that were found in the NBF and PR fraction. Amino acid analysis revealed that the NBI and 7S globulin had a lower content of sulfur-containing amino acids compared to NBF and the electrostatically isolated fractions. CD and fluorescence spectroscopy confirmed that denaturation of the proteins during the acid precipitation is likely. This novel solvent-free electrostatic separation process preserves the native protein structure found in NBF and improves the recovery of some of the smaller MW proteins. PMID:27132821
Digital Repository Service at National Institute of Oceanography (India)
Khodse, V.B.; Fernandes, L.; Bhosle, N.B.; Sardessai, S.
molecular weight (HMW, >10 kDa to 30 kDa), and low molecular weight (LMW, >1 kDa to 10 kDa) size fractions using an Amicon stirred 9 cell equipped with either 30 kDa, 10 kDa and 1 kDa MW cut off cellulose membrane ultra filter, respectively. Accuracy...
Li, Huiming; Wang, Jinhua; Wang, Qin'geng; Qian, Xin; Qian, Yu; Yang, Meng; Li, Fengying; Lu, Hao; Wang, Cheng
2015-02-01
A four-step sequential extraction procedure was used to study the chemical fractionation of As and heavy metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in fine particulate matter (PM2.5) collected from Nanjing, China. The mass concentrations of most PM2.5 samples exceeded the 24 h standard (75 μg/m3) recommended by the new national ambient air quality standard of China. The most abundant elements were Fe, Zn and Pb, while As and Cd were present at the lowest concentrations. As, Cd, Cu, Mn, Pb and Zn were mostly present in the two mobile fractions, including the soluble and exchangeable fraction (F1), and carbonates, oxides and reducible fraction (F2). Fe had the highest proportion present in the residual fraction (F4). Relatively high proportions of the metals Ni and Cr were present in the oxidizable and sulfidic fraction (F3). High proportions of Zn, As and Cu and lower proportions of Cd, Cr and Fe were present in the potentially mobile phases. The enrichment factor, contamination factor and risk assessment code were calculated to analyze the main sources and assess the environmental risks of the metals in PM2.5. The carcinogenic risks of As, Cd, Ni and Pb were all lower than the accepted criterion of 10-6, whereas the carcinogenic risks of Cr for children and As and Cr for adults were higher than 10-6. The non-carcinogenic health risk of As and heavy metals because of PM2.5 exposure for children and adults were lower than but close to the safe level of 1.
International Nuclear Information System (INIS)
The influence of gamma-irradiation on Fusarium-mycotoxins and the chemical composition of whole and dry-milled fractions of wheat grains was investigated. Wheat samples collected from the Egyptian markets were found to be heavily contaminated by, Fusarium graminearum (70-100%), F. moniliforme (40-60%) and F.subglutinilils (10-30%). Fusarium counts in wheat fractions were 1.1-2.7 x 101 CFU/g in flour; 1.1 x 103 to 3.7 X 104 CFU/g in bran and 1.4 x 102 to 1.6 X 103 in shorts. The levels of deoxynivalenol (DON) and zearalenone were generally highest in the bran and lowest in the flour. The levels of DON and zearalenone. in whole wheat samples were generally lower than the levels in the bran and shorts. Irradiation at a dose 5.0 kGy reduced the Fusarium moulds growth greatly relative to unirradiated controls and there was no growth at 7.0 kGy. Application of radiation at 15.0 kGy reduced the levels of DON and zearalenon by less than 1 ppm and Fusarium toxins were eliminated at 20.0 kGy. The chemical composition of the raw and irradiated whole and dry- milled fractions of-wheat grains up to 20.0 kGy was similar
Dual-tracer method to estimate coral reef response to a plume of chemically modified seawater
Maclaren, J. K.; Caldeira, K.
2013-12-01
We present a new method, based on measurement of seawater samples, to estimate the response of a reef ecosystem to a plume of an additive (for example, a nutrient or other chemical). In the natural environment, where there may be natural variability in concentrations, it can be difficult to distinguish between changes in concentrations that would occur naturally and changes in concentrations that result from a chemical addition. Furthermore, in the unconfined natural environment, chemically modified water can mix with waters that have not been modified, making it difficult to distinguish between effects of dilution and effects of chemical fluxes or transformations. We present a dual-tracer method that extracts signals from observations that may be affected by both natural variability and dilution. In this dual-tracer method, a substance (in our example case, alkalinity) is added to the water in known proportion to a passive conservative tracer (in our example case, Rhodamine WT dye). The resulting plume of seawater is allowed to flow over the study site. Two transects are drawn across the plume at the front and back of the study site. If, in our example, alkalinity is plotted as a function of dye concentration for the front transect, the slope of the resulting mixing line is the ratio of alkalinity to dye in the added fluid. If a similar mixing line is measured and calculated for the back transect, the slope of this mixing line will indicate the amount of added alkalinity that remains in the water flowing out of the study site per unit of added dye. The ratio of the front and back slopes indicates the fraction of added alkalinity that was taken up by the reef. The method is demonstrated in an experiment performed on One Tree Reef (Queensland, Australia) aimed at showing that ocean acidification is already affecting coral reef growth. In an effort to chemically reverse some of the changes to seawater chemistry that have occurred over the past 200 years, we added
Analysis of Liquid Fraction in Venturi Scrubber by E-E Method Using CFX
Directory of Open Access Journals (Sweden)
Majid Ali
2012-09-01
Full Text Available In this research, the distribution of liquid fraction in cylindrical venturi scrubber is analyzed in ANSYS CFX by Eulerian-Eulerian regime. Liquid gaps allow the aerosols to escape from the venturi scrubber. Therefore, it is vital to investigate the liquid fraction in venturi scrubber at different operating condition. The mesh model is developed in ANSYS ICEM and simulation is conducted in ANSYS CFX. k- ε turbulence model is used for simulation of two phase flow in venturi scrubber. The analysis is based on the boundary condition of mass flow rate for air inlet and static pressure for water inlet. For air mass flow rate 0.11, 0.14, 0.17 and 0.2 kg/s, respectively whereas static pressure 245 and 588 Pa for water inlet is used.
Buyukkilic, F.; Ok Bayrakdar, Z.; Demirhan, D.
2016-02-01
In this study, we investigate the cumulative diminution phenomenon for a physical quantity and a diminution process with a constant acquisition quantity in each step in a viscous medium. We analyze the existence of a dynamical mechanism that underlies the success of fractional calculus compared with standard mathematics for describing stochastic processes by proposing a Fibonacci approach, where we assume that the complex processes evolves cumulatively in fractal space and discrete time. Thus, when the differential-integral order α is attained, this indicates the involvement of the viscosity of the medium in the evolving process. The future value of the diminishing physical quantity is obtained in terms of the Mittag-Leffler function (MLF) and two rheological laws are inferred from the asymptotic limits. Thus, we conclude that the differential-integral calculus of fractional mathematics implicitly embodies the cumulative diminution mechanism that occurs in a viscous medium.
Bourven, Isabelle; Joussein, Emmanuel; Guibaud, Gilles
2011-07-01
This work characterises the mineral fraction of EPS extracts obtained using eight different methods from two activated sludges by total mineral content determination, Fourier Transformed Infrared spectrometry and with scanning electron microscopy coupled with an EDX probe. Despite EPS dialysis, the EPS extracts displayed a mineral fraction between 2% and 40% of the EPS dry weight depending on the extraction method used. The main mineral elements found in the EPS extract were Ca, Mg, Na, K, Al, Fe, Mn, P, Si and S, but their contents were strongly affected by the extraction method used. Some of the minerals are associated with the organic molecules within the EPS. The presence of mineral particles of various compositions and structures (clays, quartz or carbonate) in the EPS extract with a wide range in size was clearly demonstrated. Moreover, the association of metallic elements with the mineral particles in the EPS extract was highlighted. PMID:21576015
Precision measurement method for branching fractions of excited P1/2 states applied to 40Ca+
Ramm, Michael; Kokish, Mark; Talukdar, Ishan; Häffner, Hartmut
2013-01-01
We present a method for measuring branching fractions for the decay of $J = 1/2$ atomic energy levels to lower-lying states based on time-resolved recording of the atom's fluorescence during a series of population transfers. We apply this method to measure the branching fractions for the 4p$^{2}$P$_{1/2}$ decay of $^{40}$\\Ca to the 4s$^{2}$S$_{1/2}$ and 3d$^{2}$D$_{3/2}$ states to be \\branching\\ and \\branchingsm, respectively. The measurement scheme requires that at least one of the lower-lying states be long-lived. The method is insensitive to fluctuations in laser light intensity and magnetic field and is readily applicable to various atomic species due to its simplicity. Our result distinguishes well among existing state-of-the-art theoretical models of \\Ca.
DEFF Research Database (Denmark)
Le, T.H.A.; Pham, D. T.; Canh, Nam Nguyen; Le, D.M.
2010-01-01
objective function is linear, we have investigated a global algorithm based upon a branch-and-bound procedure. The algorithm uses Lagrangian bound coupling with a simplicial bisection in the criteria space. Preliminary computational results show that the global algorithm is promising.......Both the efficient and weakly efficient sets of an affine fractional vector optimization problem, in general, are neither convex nor given explicitly. Optimization problems over one of these sets are thus nonconvex. We propose two methods for optimizing a real-valued function over the efficient and...... weakly efficient sets of an affine fractional vector optimization problem. The first method is a local one. By using a regularization function, we reformulate the problem into a standard smooth mathematical programming problem that allows applying available methods for smooth programming. In case the...
Czech Academy of Sciences Publication Activity Database
Janča, Josef; Sobota, Jaroslav
2014-01-01
Roč. 19, 16 May (2014), s. 296-308. ISSN 1023-666X R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : Asymmetrical flow FFF * Electrical FFF * Field- flow fractionation * Flow FFF * Microelectrical FFF * Microfluidic channels * Microthermal FFF * Miniaturization and resolution * Polymers and particles separation * Sedimentation FFF * Technical benefits of microchannels * Thermal FFF Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.264, year: 2014
Institute of Scientific and Technical Information of China (English)
袁益让
1999-01-01
For compressible two-phase displacement problem, a kind of characteristic finite difference fractional steps schemes is put forward and thick and thin grids are used to form a complete set. Some techniques, such as piecewise biquadratic interpolation, of calculus of variations, multiplicative commutation rule of difference operators, decomposition of high order difference operators and prior estimates are adopted. Optimal order estimates in L~2 norm are derived to determine the error in the approximate solution.
High-efficiency spatial color separation method based on fractional Talbot effect
Institute of Scientific and Technical Information of China (English)
Qiaofeng Tan; Yan Zhang; Guofan Jin
2009-01-01
@@ Based on fractional Talbot effect, Talbot grating is adopted to realize spatial color separation with high light efficiency.For red and green colors, a two-step Talbot grating is optimized and the light efficiency reaches over 95%.The two-step Talbot grating is fabricated and tested.Experimental results show that the Talbot grating indeed has the good ability of spatial color separation.
The use of Computational Methods for the Assessment of Chemicals in REACH
Tsakovska I.; Worth A.
2009-01-01
This article provides an overview of the use of computational methods in chemicals hazard and risk assessment under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) legislation. The key aspects of the REACH guidance on the assessment of chemicals are discussed that treat the possible stepwise (tiered) approach combining multiple computational methods in assessing chemicals. Several publicly accessible software tools for the computer-based estimation of chemical...
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
In this paper, the feasibility of measuring the gas volume fraction in a mixed gas-liquid flow by using an acoustic resonant spectroscopy (ARS) method in a transient way is studied theoretically and experimentally. Firstly, the effects of sizes and locations of a single air bubble in a cylindrical cavity with two open ends on resonant frequencies are investigated numerically. Then, a transient measurement system for ARS is established, and the trends of the resonant frequencies (RFs) and resonant amplitudes (RAs) in the cylindrical cavity with gas flux inside are investigated experimentally. The measurement results by the proposed transient method are compared with those by steady-state ones and numerical ones. The numerical results show that the RFs of the cavity are highly sensitive to the volume of the single air bubble. A tiny bubble volume perturbation may cause a prominent RF shift even though the volume of the air bubble is smaller than 0.1% of that of the cavity. When the small air bubble moves, the RF shift will change and reach its maximum value as it is located at the middle of the cavity. As the gas volume fraction of the two-phase flow is low, both the RFs and RAs from the measurement results decrease dramatically with the increasing gas volume, and this decreasing trend gradually becomes even as the gas volume fraction increases further. These experimental results agree with the theoretical ones qualitatively. In addition, the transient method for ARS is more suitable for measuring the gas volume fraction with randomness and instantaneity than the steady-state one, because the latter could not reflect the random and instant characteristics of the mixed fluid due to the time consumption for frequency sweeping. This study will play a very important role in the quantitative measurement of the gas volume fraction of multiphase flows.
Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. First Update. (3rd edition)
International Nuclear Information System (INIS)
The proposed Update is for Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846, Third Edition. Attached to the report is a list of methods included in the proposed update indicating whether the method is a new method, a partially revised method, or a totally revised method. Do not discard or replace any of the current pages in the SW-846 manual until the proposed update I package is promulgated. Until promulgation of the update package, the methods in the update package are not officially part of the SW-846 manual and thus do not carry the status of EPA-approved methods. In addition to the proposed Update, six finalized methods are included for immediate inclusion into the Third Edition of SW-846. Four methods, originally proposed October 1, 1984, will be finalized in a soon to be released rulemaking. They are, however, being submitted to subscribers for the first time in the update. These methods are 7211, 7381, 7461, and 7951. Two other methods were finalized in the 2nd Edition of SW-846. They were inadvertantly omitted from the 3rd Edition and are not being proposed as new. These methods are 7081 and 7761
Study on Chemical Constituents of Ethyl Acetate Fraction of Euscaphis japonica%鸡眼睛乙酸乙酯部位化学成分研究
Institute of Scientific and Technical Information of China (English)
周雯; 刘智; 王海军; 李勇军; 王爱民; 许祖超; 廖尚高
2013-01-01
Objective; To investigate the chemical constituents of the ethyl acetate fraction of ethanol extract of Euscaphis japonica. Method; Various preparative chromatographic techniques were used for the isolation and purification of the compounds and their structures were determined by comparison of their chromatographic and spectral data with those of the authentic samples and those reported in the literature. Result; Seven compounds were obtained and identified as vanillin (1) , vanillic acid (2) , 5-hydroxymethylfurfural (3) , sinapic aldehyde (4), oleanolic acid (5), gallic acid (6), and protocatechuic acid (7). Conclusion; Compounds 2-7 were isolated from the genus Euscaphis for the first time.%目的:研究鸡眼睛乙醇提取物中等极性的乙酸乙酯萃取部位的化学成分,为民族药鸡眼睛的开发应用提供科学依据.方法:通过各种色谱分离技术对鸡眼睛乙醇提取物乙酸乙酯萃取部位进行分离纯化,根据化合物的理化性质和波谱数据鉴定其结构.结果:从鸡眼睛乙醇提取物乙酸乙酯萃取部位分离得到7个化合物,分别鉴定为:香草醛(vanillin,1),香草酸(vanillic acid,2),5-羟甲基糠醛(5-hydroxymethylfurfural,3),芥子醛(sinapic aldehyde,4),齐墩果酸(oleanolic acid,5),没食子酸(gallic acid,6),原儿茶酸(protocatechuic acid,7).结论:其中化合物2～7为首次从该属植物中分离得到.
Convolution method and CTV-to-PTV margins for finite fractions and small systematic errors
Energy Technology Data Exchange (ETDEWEB)
Gordon, J J; Siebers, J V [Department of Radiation Oncology, Virginia Commonwealth University, PO Box 980058, Richmond, VA 23298 (United States)
2007-04-07
The van Herk margin formula (VHMF) relies on the accuracy of the convolution method (CM) to determine clinical target volume (CTV) to planning target volume (PTV) margins. This work (1) evaluates the accuracy of the CM and VHMF as a function of the number of fractions N and other parameters, and (2) proposes an alternative margin algorithm which ensures target coverage for a wider range of parameter values. Dose coverage was evaluated for a spherical target with uniform margin, using the same simplified dose model and CTV coverage criterion as were used in development of the VHMF. Systematic and random setup errors were assumed to be normally distributed with standard deviations {sigma} and {sigma}. For clinically relevant combinations of {sigma}, {sigma} and N, margins were determined by requiring that 90% of treatment course simulations have a CTV minimum dose greater than or equal to the static PTV minimum dose. Simulation results were compared with the VHMF and the alternative margin algorithm. The CM and VHMF were found to be accurate for parameter values satisfying the approximate criterion: {sigma}[1 - {gamma}N/25] < 0.2, where {gamma} = {sigma}/{sigma}. They were found to be inaccurate for {sigma}[1 - {gamma}N/25] > 0.2, because they failed to account for the non-negligible dose variability associated with random setup errors. These criteria are applicable when {sigma} {approx}> {sigma}{sub P}, where {sigma}{sub P} = 0.32 cm is the standard deviation of the normal dose penumbra. (Qualitative behaviour of the CM and VHMF will remain the same, though the criteria might vary if {sigma}{sub P} takes values other than 0.32 cm.) When {sigma} << {sigma}{sub P}, dose variability due to random setup errors becomes negligible, and the CM and VHMF are valid regardless of the values of {sigma} and N. When {sigma} {approx}> {sigma}{sub P}, consistent with the above criteria, it was found that the VHMF can underestimate margins for large {sigma}, small {sigma} and small
Sakhare, Suresh D; Inamdar, Aashitosh A; Gaikwad, Shwetha B; D, Indrani; G, Vekateswara Rao
2014-12-01
In the view of recent growing interest in utilization of grain fractions as food ingredient, present investigation was carried out to evaluate the roller milling potential of green gram. The effect of conditioning moistures on green gram roller milling were studied. The results showed decrease in flour yield from 85.56 to 58.74 % with increase in conditioning moisture from 10 to 16 %. Higher yield of flour was observed from the first (C1), second (C2) and third (C3) reduction passages; whereas, the first (B1), second (B2) and third (B3) break passages produced less flour. The distribution of protein, dietary fiber, ash and fat in different flour streams and by-products from roller milled fractions of green gram showed wide variation. The protein content increased with increasing numbers of breaks and reductions in the flour streams. The highest protein content of 30.16 % was found in bran duster flour and lowest (11.32 %) in fine seed coat. The protein content of break streams was found lower than reduction streams. The dietary fiber content of coarse seed coat was highest (71.17 %) followed by the fine seed coat (57.22 %). The microstructure studies of milled fractions of green gram showed more deformed and damaged starch granules in reduction flour streams than break flour streams. PMID:25477653
Treatment of cork process wastewater by a successive chemical-physical method.
Beltrán de Heredia, Jesús; Domínguez, Joaquin R; López, Raquel
2004-07-14
In cork processing, the operation of boiling the raw cork generates large volumes of wastewater which are more often than not released directly into the environment untreated. Even when the wastewater is treated, this is usually by retention in evaporation ponds. This procedure, however, causes bad odors and may pollute surface water and groundwater. The present study evaluates a physicochemical method involving Fenton oxidation and coagulation/flocculation for the removal of chemical oxygen demand (COD), total polyphenols (TP), and aromatic compounds (A) from cork manufacturing process wastewater. The experimental variables studied were the dosages of iron salts (from 0.001 to 0.2 mol/L) and hydrogen peroxide (between 0.06 and 1 mol/L). The integrated Fenton-coagulation/flocculation process reduced the COD of the effluent by from 22% to 85%. The removal of total polyphenols ranged from 4% to 98%, and of aromatic compounds from 2% to 97%. A further two experiments were performed modifying the manner in which the reagents were added, splitting the reagent dose (of hydrogen peroxide and ferrous salt) into two and three fractions. Finally, an economic study was made of the chemical costs deriving from the application of this purification system. The cost of a treatment with an [H2O2](o)/COD(o) ratio of 1.8 g/g (splitting the reagent dose into three fractions) that yields a COD removal of 73% was estimated to be 11.5 euros/m(3) of wastewater. PMID:15237958
International Nuclear Information System (INIS)
The concentration of more than 25 trace elements have been determined in total air particulate matter and in the size segregated fractions from the urban area of Pavia (North Italy). The PM10 fraction was also collected and analyzed. A study of the solubility in water and in physiological solution of the trace elements contained in the PM10 was also carried out. The resulting solutions were further submitted to column chromatography using Chelex 100 to perform a preliminary chemical characterization. INAA was used as the main analytical technique. ET-AAS was used for all Pb and Cd measurements and, in some cases, for the analysis of V, Mn, Cu and Ni. (author)
International Nuclear Information System (INIS)
In the oil industry it is very important to know the composition of the crude oil fractions, since it varies depending on their origin. It is feasible and profitable their industrial separation by distillation in fractions of different boiling points intervals for dissimilar applications, but before carrying out the industrial process it is necessary to determine in the laboratory the composition of each fraction for the adaptation of this purpose. Usually this is implemented by distillation at atmospheric and reduced pressures of the oil samples, although this determination could be made by simulated distillation using gas chromatography. A method of gas chromatography simulated distillation was established in order to its future application in Cuban refinery laboratories. It was performed using capillary gas chromatography with flame ionization detector. The test method consisted on a modification of the standard ASTM D5307-07 which establishes the use of packed columns, which were substituted by capillary columns. The samples were analyzed using a mixture of n-paraffins as internal standard (n-hexadecane, n-heptadecane, n-octadecane and n-nonadecane.). The tests of column resolution, determinations of the response factors and retention times repeatability were carried out. The statistical analysis shows good results in the repeatability and reproducibility tests. The composition of the different fractions of a number of samples of oil was obtained and they were compared with the results obtained by the classical method of True Boiling Points ASTM D 2892-05, being similar in both methods. It can be concluded that this method is possible to implant
DEFF Research Database (Denmark)
Kristensen, Mette; Savorani, Francesco; Ravn-Haren, Gitte; Poulsen, Morten; Markowski, Jaroslaw; Larsen, Flemming H.; Dragsted, Lars O.; Engelsen, Søren B.
2010-01-01
data and the NMR spectra, an interval partial least-square (iPLS) regression model to predict the amount of cholesterol in the different lipoprotein fractions was developed. The relative errors of the prediction models were between 12 and 33% and had correlation coefficients (r) between 0.96 and 0.......84. The models were tested with an independent test set giving prediction errors between 19 and 46% and r between 0.96 and 0.76. Prediction of High, Low and Very Low Density Lipoprotein (HDL, LDL and VLDL) and total cholesterol was conducted in a study where rats had been supplemented with two doses of...
Method of chemical analysis of silicate rocks (1962)
International Nuclear Information System (INIS)
A rapid method of analysis for the physical and chemical determination of the major constituents of silicate rocks is described. Water losses at 100 deg. C and losses of volatile elements at 1000 deg. C are estimated after staying in oven for these temperatures, or by mean of a thermo-balance. The determination of silica is made by a double insolubilization with hydrochloric acid on attack solution with sodium carbonate; total iron and aluminium, both with calcium and magnesium, after ammoniacal precipitation of Fe and Al, are determined on the filtration product of silica by titrimetry-photometry of their complexes with EDTA. The alkalis Na and K by flame spectrophotometry, Mn by colorimetry of the permanganate, and Ti by mean of his complex with H2O2, are determined on fluosulfuric attack solution. Phosphorus is determined by his complex with 'molybdenum blue' on a fluoro-nitro-boric attack solution; iron is estimated by potentiometry, with the help of bichromate on hydrofluoric solution. (author)
Studies of coupled chemical and catalytic coal conversion methods
Energy Technology Data Exchange (ETDEWEB)
Stock, L.M.
1988-01-01
Liquefaction of coal by depolymerization in an organic solvent has been studied for several years. The liquefied coal extract which results from such a process is far more suitable for conversion into liquid fuel by hydrogenolysis than is the untreated coal. Investigations on the chemical structure and the reactive sites of coal can help to select useful reactions for the production of liquids from coal. Sternberg et al. demonstrated that the reductive alkylation method transforms bituminous coal into an enormously soluble substance, irrespective of the mild reaction conditions. The effectiveness of newly introduced alkyl groups for the disruption of intermolecular hydrogen bonds and pi-pi interactions between the aromatic sheets in coal macromolecules has been recognized. It has been reported by Ignasiak et al. that a C-alkylabon reaction using sodium or potassium amide in liquid ammonia can be used to introduce alkyl groups at acidic carbon sites. A method has been developed recently in this laboratory for the solubilization of high rank coals. In the previous reports it was shown that n-butyl lithium and potassium t-butoxide in refluxing heptane produced coal anions which could be alkylated with different alkyl halides. Such alkylated coals were soluble up to 92% in solvents like pyridine. Though the solubilization of coal depended very much on the length of the alkyl group, it also depended very much on the nature of the base used. Strong bases like n-butyl lithium (pKa=42) can cause proton abstraction from aromatic structures, if the more acidic benzylic protons are absent. The utility of this procedure, initially developed and used by Miyake and Stock, has now been tested with the high oxygen containing, low rank Illinois No. 6 and Wyodak coals.
Physical and chemical methods for the characterization of hazardous wastes
Francis, C. W.; Maskarinec, M. P.; Lee, D. W.
Numerous test methods have been proposed and developed to evaluate the hazards associated with handling and disposal of wastes in landfills. The major concern is the leaching of toxic constituents from the wastes. The fate of hazardous constituents in landfilled wastes is highly dependent on the physical and chemical characteristics of the waste. Thus, the primary objective in the selection of waste characterization procedures should be focused on those methods that gauge the fate of the waste's hazardous constituents in a specific landfill environment. Waste characterization in the United States has centered around the characteristics of ignitability, corrosivity, reactivity, and toxicity. The strategy employed in the development of most regulatory waste characterization procedures has been a pass or fail approach, usually tied to some form of a mismanagement scenario for that waste. For example, USEPA has chosen the disposal of a waste in a municipal waste landfill as a mismanagement scenario for the development of the waste leaching tests to determine the toxicity characteristic. Many wastes, such as large-volume utility wastes or mining wastes, are not disposed of in municipal waste landfills. As a consequence, more effort is needed in the development of waste leaching tests that determine the long-term leaching characteristics of that waste in the landfill environment in which the waste is to be disposed. Waste leaching models also need to be developed and tested as to their ability to simulate actual disposal environments. These models need to be compared with laboratory leaching tests, and, if practical, coupled with groundwater transport models.
Comparative Study of Chemical Methods for Fuel Removal
International Nuclear Information System (INIS)
Full text: To extend the availability of ITER, tritium stored in the vessel has to be removed on a regular basis. The research on the fuel removal at Forschungszentrum Juelich has been concentrated in recent years on chemical methods including thermo-chemical erosion (TCE) also known as baking in reactive gases, glow-discharge conditioning (GDC) and ion-cyclotron wall conditioning (ICWC). The studies were conducted in the tokamak TEXTOR and in laboratory devices using pre-characterized samples with deuterated carbon layers. GDC, in contrast to TCE and ICWC, is not applicable in the presence of the nominal magnetic field. Our investigations showed that GDC can be operated at a magnetic field of up to 10 mT and is therefore compatible with the ferritic inserts foreseen in ITER. The TCE using oxygen as the removal gas can effectively be employed at elevated temperatures of at least 300°C. Plasma-based GDC and ICWC can also be applied at lower wall temperatures. TCE is equally efficient in cleaning from the wall surface as from the remote areas such as gaps of castellations. GDC is homogeneous along the wall surface except for small recessed areas like gaps. ICWC is typically inhomogeneous along the poloidal circumference. Applying the radial magnetic field, we were able to control the poloidal position of the main IC plasma production. Thus, some wall regions, e.g., the divertor, can selectively be exposed to ICWC. Owing to higher ion fluxes to the wall, ICWC activates a larger amount of neutrals than GDC, which then penetrate in gaps and clean gap walls efficiently. Removal rates with oxygen were typically by a factor of 3 - 10 higher than with hydrogen and ammonia and 10 - 30 than with nitrogen. The estimates using the highest removal rate for ICWC show that about 2 hours are needed to remove the layer deposited within one ITER pulse. The application of ammonia in TCE led to the pealing-off of layers, which is a potential dust production mechanism. However, it
Chan, Leo Li-Ying; Cohen, Donald A; Kuksin, Dmitry; Paradis, Benjamin D; Qiu, Jean
2014-07-01
In recent years, the lipoaspirate collected from adipose tissue has been seen as a valuable source of adipose-derived mesenchymal stem cells for autologous cellular therapy. For multiple applications, adipose-derived mesenchymal stem cells are isolated from the stromal vascular fraction (SVF) of adipose tissue. Because the fresh stromal vascular fraction typically contains a heterogeneous mixture of cells, determining cell concentration and viability is a crucial step in preparing fraction samples for downstream processing. Due to a large amount of cellular debris contained in the SVF sample, as well as counting irregularities standard manual counting can lead to inconsistent results. Advancements in imaging and optics technologies have significantly improved the image-based cytometric analysis method. In this work, we validated the use of fluorescence-based image cytometry for SVF concentration and viability measurement, by comparing to standard flow cytometry and manual hemocytometer. The concentration and viability of freshly collected canine SVF samples are analyzed, and the results highly correlated between all three methods, which validated the image cytometry method for canine SVF analysis, and potentially for SVF from other species. PMID:24740550
DEFF Research Database (Denmark)
Götze, Ramona; Pivnenko, Kostyantyn; Boldrin, Alessio;
2016-01-01
Physico-chemical waste composition data are paramount for the assessment and planning of waste management systems. However, the applicability of data is limited by the regional, temporal and technical scope of waste characterisation studies. As Danish and European legislation aims for higher...
International Nuclear Information System (INIS)
Acrylic rubbers (ACM) carboxylated by acrylic acid or itaconic acid were prepared by 60Co γ-ray or chemical-initiator (K2S2O8) induced emulsion copolymerization. The polymers were characterized by Fourier transform infrared spectroscopy (FT-IR). Acid value, molecular weight and polydispersity index (PDI) of the polymers were determined by non-aqueous titration method and gel permeation chromatography (GPC), respectively. Vulcanization and mechanical properties of the filled ACM were studied by rheometric measurement, gel fraction analysis, mechanical property tests and dynamic mechanical thermal analysis (DMTA). The results show that the ACMs prepared by γ-ray irradiation have lower acid value, higher molecular weight and narrower PDI than chemically prepared ACMs of the same compositions. The itaconic acid carboxylated ACM has better cure characteristics and mechanical properties than the acrylic acid carboxylated ACM. The itaconic acid carboxylated ACM prepared by γ-ray irradiation has higher gel fraction and better cure characteristics as well as mechanical properties than that prepared by chemical method. (authors)
Xu, Xu-Ping; Gan, Hai-Yan; Li, Fen-xia; Tian, Qi; Zhang, Jun; Liang, Rong-Liang; LI Ming; Yang, Xue-Xi; Wu, Ying-Song
2016-01-01
Objective The fraction of circulating cell-free fetal (cff) DNA in maternal plasma is a critical parameter for aneuploidy screening with non-invasive prenatal testing, especially for those samples located in equivocal zones. We developed an approach to quantify cff DNA fractions directly with sequencing data, and increased cff DNAs by optimizing library construction procedure. Methods Artificial DNA mixture samples (360), with known cff DNA fractions, were used to develop a method to determin...
Zilbergleyt, B
2002-01-01
The article compares traditional coefficients of thermodynamic activity as a parameter related to individual chemical species to newly introduced reduced chaotic temperatures as system characteristics, both regarding their usage in thermodynamic simulation of open chemical systems. Logical and mathematical backgrounds of both approaches are discussed. It is shown that usage of reduced chaotic temperatures and the Method of Chemical Dynamics to calculate chemical and phase composition in open chemical systems is much less costly, easier to perform and potentially leads to better precision.
Vincenzo, Fiorenzo; Spitoni, Emanuele
2016-01-01
In this Letter, we present a new theoretical method for solving the chemical evolution of galaxies, by assuming the instantaneous recycling approximation for chemical elements restored by massive stars and the Delay Time Distribution formalism for the delayed chemical enrichment by Type Ia Supernovae. The galaxy gas mass assembly history, together with the assumed stellar yields and initial mass function, represent the starting point of this method. We derive a very simple and general equation which closely relates the Laplace transforms of the galaxy gas accretion and star formation history, which can be used to simplify the problem of retrieving these quantities in most of current galaxy evolution models. We find that - once the galaxy star formation history has been reconstructed from our assumptions - the differential equation for the evolution of the chemical element $X$ can be suitably solved with classical methods. We apply our model to reproduce the $[\\text{O/Fe}]$ and $[\\text{Si/Fe}]$ vs. $[\\text{Fe/...
Silas R. Ferreira; Fabio R. Barreira; Luciana S. Spinelli; Katia Z. Leal; Peter Seidl; Elizabete F. Lucas
2016-01-01
Asphaltenes are blamed for various problems in the petroleum industry, especially formation of solid deposits and stabilization of water-in-oil emulsions. Many studies have been conducted to characterize chemical structures of asphaltenes and assess their phase behavior in crude oil or in model-systems of asphaltenes extracted from oil or asphaltic residues from refineries. However, due to the diversity and complexity of these structures, there is still much to be investigated. In this study,...
International Nuclear Information System (INIS)
Since volumetric dose distributions are available with 3-dimensional radiotherapy treatment planning they can be used in statistical evaluation of response to radiation. This report presents a method to calculate the influence of dose inhomogeneity and fractionation in normal tissue complication probability evaluation. The mathematical expression for the calculation of normal tissue complication probability has been derived combining the Lyman model with the histogram reduction method of Kutcher et al. and using the normalized total dose (NTD) instead of the total dose. The fitting of published tolerance data, in case of homogeneous or partial brain irradiation, has been considered. For the same total or partial volume homogeneous irradiation of the brain, curves of normal tissue complication probability have been calculated with fraction size of 1.5 Gy and of 3 Gy instead of 2 Gy, to show the influence of fraction size. The influence of dose distribution inhomogeneity and α/β value has also been simulated: Considering α/β=1.6 Gy or α/β=4.1 Gy for kidney clinical nephritis, the calculated curves of normal tissue complication probability are shown. Combining NTD calculations and histogram reduction techniques, normal tissue complication probability can be estimated taking into account the most relevant contributing factors, including the volume effect. (orig.)
Xu, Xu-Ping; Gan, Hai-Yan; Li, Fen-Xia; Tian, Qi; Zhang, Jun; Liang, Rong-Liang; Li, Ming
2016-01-01
Objective The fraction of circulating cell-free fetal (cff) DNA in maternal plasma is a critical parameter for aneuploidy screening with non-invasive prenatal testing, especially for those samples located in equivocal zones. We developed an approach to quantify cff DNA fractions directly with sequencing data, and increased cff DNAs by optimizing library construction procedure. Methods Artificial DNA mixture samples (360), with known cff DNA fractions, were used to develop a method to determine cff DNA fraction through calculating the proportion of Y chromosomal unique reads, with sequencing data generated by Ion Proton. To validate our method, we investigated cff DNA fractions of 2,063 pregnant women with fetuses who were diagnosed as high risk of fetal defects. The z-score was calculated to determine aneuploidies for chromosomes 21, 18 and 13. The relationships between z-score and parameters of pregnancies were also analyzed. To improve cff DNA fractions in our samples, two groups were established as follows: in group A, the large-size DNA fragments were removed, and in group B these were retained, during library construction. Results A method to determine cff DNA fractions was successfully developed using 360 artificial mixture samples in which cff DNA fractions were known. A strong positive correlation was found between z-score and fetal DNA fraction in the artificial mixture samples of trisomy 21, 18 and 13, as well as in clinical maternal plasma samples. There was a positive correlation between gestational age and the cff DNA fraction in the clinical samples, but no correlation for maternal age. Moreover, increased fetal DNA fractions were found in group A compared to group B. Conclusion A relatively accurate method was developed to determine the cff DNA fraction in maternal plasma. By optimizing, we can improve cff DNA fractions in sequencing samples, which may contribute to improvements in detection rate and reliability. PMID:26765738
Tang, Chunlan; Wang, Li; Liu, Xinxin; Cheng, Mengchun; Xiao, Hongbin
2016-02-01
The chemical fingerprint and metabolic profile of traditional Chinese medicine is very complicated and has been a great challenge. In the present study, chemical fingerprint of ethyl acetate fraction of Gastrodia elata (EtAcGE) and metabolic profile of rat plasma sample after intragastric administration of EtAcGE (2.5g/kg) were investigated using ultra-high performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC/Q-TOF MS). A total of 38 chemical constituents of EtAcGE were identified by comparing their retention time, accurate molecular mass and characteristic fragment ions with those of references, or tentatively characterized by comparing molecular formula, fragment ions with that of known compound or information available in literature. And 40 compounds were detected in dosed rat plasma sample, including 16 prototypes and 24 metabolites underwent metabolic process of glucuronidation, glucosylation, sulfation, methylation, hydroxylation, dehydrogenation or mixed modes. The metabolic "soft spots" was hydroxyl or carboxy group. This is the first research for chemical fingerprint and metabolic profile of EtAcGE, which lay a foundation for the further investigation of EtAcGE. PMID:26621783
Blanchard, D. P.; Jacobs, J. W.; Brannon, J. C.; Brown, R. W.
1976-01-01
Each bulk soil and both the magnetic and nonmagnetic components of the 90-150 micron and below 20 micron fractions of five soils from drive tube 60009 were analyzed. Samples were analyzed for FeO, Na2O, Sc, Cr, Co, Ni, Hf, Ta, Th, La, Ce, Sm, Eu, Tb, Yb, and Lu by neutron activation analysis. Several samples were fused and analyzed for major elements by electron microprobe analysis. Compositional variations are not systematically related to depth. The compositions of the five soils studied are well explained by a two-component mixing model whose end members are a submature Apollo 16-type soil and an extremely immature anorthositic material similar to 60025. There is evidence that the anorthositic component had received a small amount of exposure before these soils were mixed. After mixing, the soils received little exposure suggesting mixing and deposition on a rapid time scale.
Complex chemical dynamics through engineering-like methods
Moro, Lorenzo
2014-01-01
Most of the problems in modern structural design can be described with a set of equation; solutions of these mathematical models can lead the engineer and designer to get info during the design stage. The same holds true for physical-chemistry; this branch of chemistry uses mathematics and physics in order to explain real chemical phenomena. In this work two extremely different chemical processes will be studied; the dynamic of an artificial molecular motor and the generation and propagation ...
Monodispersive CoPt Nanoparticles Synthesized Using Chemical Reduction Method
Institute of Scientific and Technical Information of China (English)
SHEN Cheng-Min; HUI Chao; YANG Tian-Zhong; XIAO Cong-Wen; CHEN Shu-Tang; DING Hao; GAO Hong-Jun
2008-01-01
@@ Monodispersive CoPt nanoparticles in sizes of about 2.2 nm are synthesized by superhydride reduction of CoCl2 and PtCl2 in diphenyl ether. The as-prepared nanoparticles show a chemically disordered A1 structure and are superparamagnetic. Thermal annealing transforms the A1 structure into chemically ordered L1o structure and the particles are ferromagnetic at room temperature.
Energy Technology Data Exchange (ETDEWEB)
Ahlner, Alexandra; Andresen, Cecilia; Khan, Shahid N. [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden); Kay, Lewis E. [The University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry, One King’s College Circle (Canada); Lundström, Patrik, E-mail: patlu@ifm.liu.se [Linköping University, Division of Chemistry, Department of Physics, Chemistry and Biology (Sweden)
2015-07-15
A selective isotope labeling scheme based on the utilization of [2-{sup 13}C]-glycerol as the carbon source during protein overexpression has been evaluated for the measurement of excited state {sup 13}Cα chemical shifts using Carr–Purcell–Meiboom–Gill (CPMG) relaxation dispersion (RD) experiments. As expected, the fractional incorporation of label at the Cα positions is increased two-fold relative to labeling schemes based on [2-{sup 13}C]-glucose, effectively doubling the sensitivity of NMR experiments. Applications to a binding reaction involving an SH3 domain from the protein Abp1p and a peptide from the protein Ark1p establish that accurate excited state {sup 13}Cα chemical shifts can be obtained from RD experiments, with errors on the order of 0.06 ppm for exchange rates ranging from 100 to 1000 s{sup −1}, despite the small fraction of {sup 13}Cα–{sup 13}Cβ spin-pairs that are present for many residue types. The labeling approach described here should thus be attractive for studies of exchanging systems using {sup 13}Cα spin probes.
Roth, D. J.; Swickard, S. M.; Stang, D. B.; Deguire, M. R.
1990-01-01
A review and statistical analysis of the ultrasonic velocity method for estimating the porosity fraction in polycrystalline materials is presented. Initially, a semi-empirical model is developed showing the origin of the linear relationship between ultrasonic velocity and porosity fraction. Then, from a compilation of data produced by many researchers, scatter plots of velocity versus percent porosity data are shown for Al2O3, MgO, porcelain-based ceramics, PZT, SiC, Si3N4, steel, tungsten, UO2,(U0.30Pu0.70)C, and YBa2Cu3O(7-x). Linear regression analysis produced predicted slope, intercept, correlation coefficient, level of significance, and confidence interval statistics for the data. Velocity values predicted from regression analysis for fully-dense materials are in good agreement with those calculated from elastic properties.
International Nuclear Information System (INIS)
A review and statistical analysis of the ultrasonic velocity method for estimating the porosity fraction in polycrystalline materials is presented. Initially, a semi-empirical model is developed showing the origin of the linear relationship between ultrasonic velocity and porosity fraction. Then, from a compilation of data produced by many researchers, scatter plots of velocity versus percent porosity data are shown for Al2O3, MgO, porcelain-based ceramics, PZT, SiC, Si3N4, steel, tungsten, UO2,(U0.30Pu0.70)C, and YBa2Cu3O(7-x). Linear regression analysis produced predicted slope, intercept, correlation coefficient, level of significance, and confidence interval statistics for the data. Velocity values predicted from regression analysis for fully-dense materials are in good agreement with those calculated from elastic properties
Flow method and apparatus for screening chemicals using micro x-ray fluorescence
Warner, Benjamin P.; Havrilla, George J.; Miller, Thomasin C.; Lewis, Cris; Mahan, Cynthia A.; Wells, Cyndi A.
2009-04-14
Method and apparatus for screening chemicals using micro x-ray fluorescence. A method for screening a mixture of potential pharmaceutical chemicals for binding to at least one target binder involves flow-separating a solution of chemicals and target binders into separated components, exposing them to an x-ray excitation beam, detecting x-ray fluorescence signals from the components, and determining from the signals whether or not a binding event between a chemical and target binder has occurred.
Chen, Qingcai; Ikemori, Fumikazu; Higo, Hayato; Asakawa, Daichi; Mochida, Michihiro
2016-02-16
The chemical characteristics of complex organic matter in atmospheric aerosols remain poorly understood. Water-insoluble organic matter (WISOM) and water-soluble organic matter (WSOM) in the total suspended particulates collected in the city of Nagoya in summer/early autumn and winter were extracted using multiple solvents. Two fractions of humic-like substances, showing neutral and acidic behavior (HULIS-n and HULIS-a, respectively), and the remaining highly polar part (HP-WSOM) were fractionated from WSOM using solid phase extraction. The chemical structural characteristics and concentrations of the organic matter were investigated using mass spectrometry and Fourier transform infrared (FT-IR) spectroscopy. WISOM and HULIS-n had low O/C ratios (0.1 and 0.4, respectively) and accounted for a large fraction of the organics in aerosols (70%). HULIS-a and HP-WSOM had higher O/C ratios (0.7 and 1.0, respectively), and their concentrations in summer and early autumn were on average ∼2 times higher than those in winter. The mass spectrum and FT-IR analyses suggest the following: (1) WISOM were high-molecular-weight aliphatics (primarily C27-C32) with small proportions of -CH3, -OH, and C═O groups; (2) HULIS-n was abundant in aliphatic structures and hydroxyl groups (primarily C9-C18) and by branched structures; (3) HULIS-a and HP-WSOM contained relatively large amounts of low-molecular-weight carboxylic acids and alcohols (primarily C4-C10); and (4) WISOM and HULIS-n were relatively abundant in amines and organic nitrates. PMID:26771766
He, Y T; Zhang, W J; Xu, M G; Tong, X G; Sun, F X; Wang, J Z; Huang, S M; Zhu, P; He, X H
2015-11-01
Soil organic carbon (SOC), total nitrogen (TN), microbial biomass carbon (MBC) and nitrogen (MBN) are important factors of soil fertility. However, effects of the combined chemical fertilizer and organic manure or straw on these factors and their relationships are less addressed under long-term fertilizations. This study addressed changes in SOC, TN, MBC and MBN at 0-20 cm soil depth under three 17 years (September 1990-September 2007) long-term fertilization croplands along a heat and water gradient in China. Four soil physical fractions (coarse free and fine free particulate organic C, cfPOC and ffPOC; intra-microaggregate POC, iPOC; and mineral associated organic C, MOC) were examined under five fertilizations: unfertilized control, chemical nitrogen (N), phosphorus (P) and potassium (K) (NPK), NPK plus straw (NPKS, hereafter straw return), and NPK plus manure (NPKM and 1.5NPKM, hereafter manure). Compared with Control, manure significantly increased all tested parameters. SOC and TN in fractions distributed as MOC > iPOC > cfPOC > ffPOC with the highest increase in cfPOC (329.3%) and cfPTN (431.1%), and the lowest in MOC (40.8%) and MTN (45.4%) under manure. SOC significantly positively correlated with MBC, cfPOC, ffPOC, iPOC and MOC (R(2) = 0.51-0.84, P fraction. Our results demonstrated that cfPOC was a sensitive SOC indicator and manure addition was the best fertilization for improving soil fertility while straw return should take into account climate factors in Chinese croplands. PMID:26119378
Evaluation of methods to test chemicals suitability for umbilical applications
Energy Technology Data Exchange (ETDEWEB)
Allenson, S. J.; Lindeman, O. E.; Cenegy, L. M.
2006-03-15
Offshore deep-water projects are increasingly deploying chemicals to sub-sea wellheads through umbilical lines. There is no margin for error in umbilical chemical treatment programs since any flow blockage in a sub-sea line would result in a multi-million dollar problem. Chemicals for umbilical delivery must also meet strict requirements in their performance and especially their handling properties. Umbilical delivery must be effective at low concentrations in preventing corrosion, scale, hydrates, asphaltenes, paraffin and a host of other problems. Chemical transiting an umbilical can experience pressures as high as 15,000 psi and temperatures ranging from near 0 deg C to greater than 120 deg C. Since some umbilicals are as long as 80 km, a week or more can elapse from the time the chemical is injected at the platform until it reaches the sub-sea well. Therefore, the chemical must not only be stable under all temperature and pressure conditions that it may experience in the umbilical line, it must also be stable under these conditions for a long period of time. Since many umbilical lines actually terminate into sub-sea valves and connectors that are only a few hundred microns in diameter, it is critical that the injected chemical have a low viscosity at sub-sea temperatures and pressures and that it be completely free of particles. These issues present substantial challenges in formulating and manufacturing chemicals for umbilical applications that must be addressed prior to approval of a product for use. Each of these challenges was taken into consideration and a series of tests were developed to assure reliable chemical pump ability through an umbilical line. The tests developed included enhanced formulation stability tests under umbilical temperature and pressure conditions, NAS Class rating, extensive material compatibility testing to include all metals and elastomers that may be used in umbilical injection systems and comprehensive physical property testing
Radiocarbon from Pile Graphite; Chemical Methods for Its Concentrations
Arnold, J. R.; Libby, W. F.
1946-10-10
Samples of pile graphite, irradiated in a test-hole at Hanford for 15 months, have been assayed for radioactive C{sup 14} yielding 0.38 ± 0.04 microcuries per gram. At this level of activity, the pile graphite contains very valuable amounts of C{sup14}. The relation between the above assay and the probable average assay of pile graphite is discussed, and it is concluded that the latter is almost certainly above 0.3 microcuries/gram. Controlled oxidation of this graphite, either with oxygen at ~750ºC, or with chromic acid "cleaning solution" at room temperature, yields early fractions which are highly enriched in C{sup 14}. Concentrations of 5-fold with oxygen, and 50-fold with CrO{sub 3}, have been observed. The relation between the observed enrichment and the Wigner effect is discussed, and a mechanism accounting for the observations put forward. According to this, about 25% of the stable carbon atoms in the lattice have been displaced by Wigner effect, a large fraction of which have healed by migrating to crystal edges. All the C{sup 14} atoms have been displaced, and the same fraction of these migrate to the edges. The enrichment then results from surface oxidation, in the oxygen case. Predictions are made on the basis of this hypothesis. A technique of counting radioactive CO{sub 2} in the gas phase is described.
Directory of Open Access Journals (Sweden)
Xu-Ping Xu
Full Text Available The fraction of circulating cell-free fetal (cff DNA in maternal plasma is a critical parameter for aneuploidy screening with non-invasive prenatal testing, especially for those samples located in equivocal zones. We developed an approach to quantify cff DNA fractions directly with sequencing data, and increased cff DNAs by optimizing library construction procedure.Artificial DNA mixture samples (360, with known cff DNA fractions, were used to develop a method to determine cff DNA fraction through calculating the proportion of Y chromosomal unique reads, with sequencing data generated by Ion Proton. To validate our method, we investigated cff DNA fractions of 2,063 pregnant women with fetuses who were diagnosed as high risk of fetal defects. The z-score was calculated to determine aneuploidies for chromosomes 21, 18 and 13. The relationships between z-score and parameters of pregnancies were also analyzed. To improve cff DNA fractions in our samples, two groups were established as follows: in group A, the large-size DNA fragments were removed, and in group B these were retained, during library construction.A method to determine cff DNA fractions was successfully developed using 360 artificial mixture samples in which cff DNA fractions were known. A strong positive correlation was found between z-score and fetal DNA fraction in the artificial mixture samples of trisomy 21, 18 and 13, as well as in clinical maternal plasma samples. There was a positive correlation between gestational age and the cff DNA fraction in the clinical samples, but no correlation for maternal age. Moreover, increased fetal DNA fractions were found in group A compared to group B.A relatively accurate method was developed to determine the cff DNA fraction in maternal plasma. By optimizing, we can improve cff DNA fractions in sequencing samples, which may contribute to improvements in detection rate and reliability.
International Nuclear Information System (INIS)
By adopting the Adomian decomposition method, the fractional-order Lorenz–Stenflo (LS) system is solved and implemented in a digital signal processor (DSP). The discrete iterative formula of the system is deduced, and a Lyapunov exponent spectrum algorithm is designed. The dynamics of the fractional-order LS system with sets of parameters are analyzed by means of Lyapunov exponent spectra, bifurcation diagrams and 0-1 test. The results illustrate that the fractional-order LS system has rich dynamic behaviors, and both the system parameter and the fractional order can be taken as bifurcation parameters. We implement the fractional-order LS system on a DSP platform. Phase portraits of the fractional-order LS system generated in the DSP agree well with those obtained by computer simulations. This lays a good foundation for the application of the fractional-order LS system. (paper)
Bernstein dual-Petrov-Galerkin method: application to 2D time fractional diffusion equation
Jani, Mostafa; Babolian, Esmail
2016-01-01
In this paper, we develop a dual-Petrov-Galerkin method using Bernstein polynomials. The method is then implemented for the numerical simulation of the two-dimensional subdiffusion equation. The method is based on a finite difference discretization in time and a spectral method in space utilizing a suitable compact combinations of dual Bernstein basis as the test functions and the Bernstein polynomials as the trial ones. We derive the exact sparse operational matrix of differentiation for the dual Bernstein basis which provides a matrix-based approach for spatial discretization of the problem. It is also shown that the proposed method leads to banded linear systems. Finally some numerical examples are provided to show the efficiency and accuracy of the method.
Research Review on Soil Active Organic Carbon Fractionation and Analytical Methods%土壤活性有机碳分组及测定方法
Institute of Scientific and Technical Information of China (English)
胡海清; 陆昕; 孙龙
2012-01-01
Soil active organic carbon as the active chemical component in organic carbon is a sensitivity index of organic carbon dynamics,which plays a very important role in the global carbon cycle and has received wide attention in the fields of Soil science,Ecology,and Environmental Science in the current research.This paper introduces the representative active carbon fractions:the characterization of dissolved organic carbon,microbial biomass carbon,mineralizable carbon,light fraction organic carbon,particulate organic carbon and briefly describes the current commonly used methods in the domestic and foreign research.%土壤活性有机碳作为土壤有机碳中活跃的化学组分,是土壤有机碳动态的敏感性指标,在全球碳循环中起着非常重要的作用,在当前的研究中,引起了土壤学、生态学和环境学界的高度关注。介绍具有代表性的活性碳组分的表征：溶解性有机碳、微生物量碳、可矿化碳、轻组有机碳、颗粒有机碳等,并对目前国内外常用的测量方法进行简要的阐述。
Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method
Institute of Scientific and Technical Information of China (English)
WANG Wen; CHENG Meng-Yun; LONG Peng-Cheng; HU Li-Qin
2015-01-01
The specific absorbed fractions (SAF) for self-and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides.A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom,which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team.The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians.In this study,the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP.Results were compared with the values from ICRP reference and ORNL models.The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models.The differences were due to the racial and anatomical differences in organ mass and inter-organ distance.The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females.
Evaluation method for uncertainty of effective delayed neutron fraction βeff
International Nuclear Information System (INIS)
Uncertainty of effective delayed neutron fraction βeff is evaluated in terms of three quantities; uncertainties of the basic delayed neutron constants, energy dependence of delayed neutron yield νdm, and the uncertainties of the fission cross sections of fuel elements. The uncertainty of βeff due to the delayed neutron yield is expressed by a linearized formula assuming that the delayed neutron yield does not depend on the incident energy, and the energy dependence is supplemented by using the detailed energy dependence proposed by D'Angelo and Filip. The third quantity, uncertainties of fission cross section, is evaluated on the basis of the generalized perturbation theory in relation to reaction rate rations such as central spectral indexes or average reaction rate ratios. Resultant uncertainty of βeff is about 4 to 5%s, in which primary factor is the delayed neutron yield, and the secondary one is the fission cross section uncertainty, especially for 238U. The energy dependence of νdm systematically reduces the magnitude of βeff about 1.4% to 1.7%, depending on the model of the energy vs. νdm correlation curve. (author)
Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method
Wang, Wen; Cheng, Meng-Yun; Long, Peng-Cheng; Hu, Li-Qin
2015-07-01
The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03040000), National Natural Science Foundation of China (910266004, 11305205, 11305203) and National Special Program for ITER (2014GB112001)
Ferrari, Mauro (Inventor); Liu, Xuewu (Inventor); Tasciotti, Ennio (Inventor); Bouamrani, Ali (Inventor); Hu, Ye (Inventor)
2014-01-01
A new fractionation device shows desirable features for exploratory screening and biomarker discovery. The constituent MSCs may be tailored for desired pore sizes and surface properties and for the sequestration and enrichment of extremely low abundant protein and peptides in desired ranges of the mass/charge spectrum. The MSCs are effective in yielding reproducible extracts from complex biological samples as small as 10 microliter in a time as short as 30 minutes. They are inexpensive to manufacture, and allow for scaled up production to attain the simultaneous processing of a large number of samples. The MSCs are multiplexed, label-free diagnostic tools with the potential of biological recognition moiety modification for enhanced specificity. The MSCs may store, protect and stabilize biological fluids, enabling the simplified and cost-effective collection and transportation of clinical samples. The MSC-based device may serve as a diagnostic tool to complement histopathology, imaging, and other conventional clinical techniques. The MSCs mediated identification of disease-specific protein signatures may help in the selection of personalized therapeutic combinations, in the real-time assessment of therapeutic efficacy and toxicity, and in the rational modulation of therapy based on the changes in the protein networks associated with the prognosis and the drug resistance of the disease.
Specific Absorbed Fractions of Electrons and Photons for Rad-HUMAN Phantom Using Monte Carlo Method
Wang, Wen; Long, Peng-cheng; Hu, Li-qin
2014-01-01
The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photon and electron were calculated using the Rad-HUMAN phantom, a computational voxel phantom of Chinese adult female and created using the color photographic image of the Chinese Visible Human (CVH) data set. The model can represent most of Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10keV to 4MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from Rad-HUMAN have the similar trends but larger than those from the other two models. The differences were due to the racial and anatomical differences in o...
Indian Academy of Sciences (India)
Sana P Ansari; Saurabh K Agrawal; Subir Das
2015-01-01
This paper presents the synchronization between a pair of identical susceptible–infected–recovered (SIR) epidemic chaotic systems and fractional-order time derivative using active control method. The fractional derivative is described in Caputo sense. Numerical simulation results show that the method is effective and reliable for synchronizing the fractional-order chaotic systems while it allows the system to remain in chaotic state. The striking features of this paper are: the successful presentation of the stability of the equilibrium state and the revelation that time for synchronization varies with the variation in fractional-order derivatives close to the standard one for different specified values of the parameters of the system.
Directory of Open Access Journals (Sweden)
Steven A. Abrams
2010-07-01
Full Text Available With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa, obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI, with that of calcium carbonate. In 10 postmenopausal women volunteers aged 59 to 77 years (mean ± S.D., 67 ± 5.3, the fractional calcium absorption of AAACa and CaCO3 was measured by a dual stable isotope method. 44Ca-enriched CaCO3 and AAACa were administered in all subjects one month apart. After a fixed-menu breakfast and pre-test urine collection (Urine 0, 42Ca-enriched CaCl2 was intravenously injected, followed by oral administration of 44Ca-enriched CaCO3 without carrier 15 minutes later, and complete urine collection for the next 24 hours (Urine 24. The fractional calcium absorption was calculated as the ratio of Augmentation of 44Ca from Urine 0 to Urine 24/ augmentation of 42Ca from Urine 0 to Urine 24. Differences and changes of 44Ca and 42Ca were corrected by comparing each with 43Ca. Fractional absorption of AAACa (mean ± S.D., 23.1 ± 6.4, was distinctly and significantly higher than that of CaCO3 (14.7 ± 6.4; p = 0.0060 by paired t-test. The mean fractional absorption was approximately 1.57-times higher for AAACa than for CaCO3. The serum 25(OH vitamin D level was low (mean ± S.D., 14.2 ± 4.95 ng/ml, as is common in this age group in Japan. Among the parameters of the bone and mineral metabolism measured, none displayed a significant correlation with the fractional absorption of CaCO3 and AAACa. Higher fractional absorption of AAACa compared with CaCO3 supports previous reports on the more beneficial effect of AAACa than CaCO3 for osteoporosis.
Brusotti, Gloria; Ibrahim, Mohammed Farhad; Dentamaro, Alessandra; Gilardoni, Gianluca; Tosi, Solveig; Grisoli, Pietro; Dacarro, Cesare; Guglielminetti, Maria Lidia; Hussain, Faiq Hama Saeed; Caccialanza, Gabriele; Vidari, Giovanni
2013-02-01
The volatile fractions isolated from Prangos peucedanifolia FENZL leaves and flowers were investigated for their phytochemical composition and biological properties. Flower and leaf hydrodistillation afforded 3.14 and 0.49 g of yellowish oils in 1.25 and 0.41% yields, respectively, from dry vegetable materials. According to the GC-FID and GC/MS analyses, 36 (99.35% of the total oil composition) and 26 compounds (89.12%) were identified in the two oils, respectively. The major constituents in the flower volatile fraction were β-pinene (35.58%), α-pinene (22.13%), and β-phellandrene (12.54%), while m-cresol (50.38%) was the main constituent of the leaf volatile fraction. The antimicrobial activity was evaluated against several bacterial and fungal strains, on the basis of the minimum inhibitory concentration (MIC) by the micro- and macrodilution methods. The two volatile fractions showed moderate antifungal and antibacterial activities, especially against Trichophyton rubrum (MIC of 2×10(3) μg/ml), Streptococcus mutans, Streptococcus pyogenes, and Staphylococcus aureus (MIC≤1.9×10(3) μg/ml for all). PMID:23418174
Wireless Chemical Sensor and Sensing Method for Use Therewith
Woodard, Stanley E. (Inventor); Oglesby, Donald M. (Inventor); Taylor, Bryant Douglas (Inventor)
2014-01-01
A wireless chemical sensor includes an electrical conductor and a material separated therefrom by an electric insulator. The electrical conductor is an unconnected open-circuit shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the first electrical conductor resonates to generate harmonic electric and magnetic field responses. The material is positioned at a location lying within at least one of the electric and magnetic field responses so-generated. The material changes in electrical conductivity in the presence of a chemical-of-interest.
Wireless Chemical Sensor and Sensing Method for Use Therewith
Woodard, Stanley E. (Inventor); Oglesby, Donald M. (Inventor); Taylor, Bryant D. (Inventor)
2016-01-01
A wireless chemical sensor includes an electrical conductor and a material separated therefrom by an electric insulator. The electrical conductor is an unconnected open-circuit shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the first electrical conductor resonates to generate harmonic electric and magnetic field responses. The material is positioned at a location lying within at least one of the electric and magnetic field responses so-generated. The material changes in electrical conductivity in the presence of a chemical-of-interest.
An Estimation Method of the Vegetation Fractions for Landsat-8/OLI
Ito, Seiji; Oguro, Yoshinari; Matsuo, Takanori
In recent years, the Urban Heat Island (UHI) in a city is one of the environmental issues. Increase green spaces (e.g. tree planting, roof or wall greening) has been possible to inhibit air temperature in the city, thus the acts of urban greening are promoted. The vegetation cover classification in a large area is one of the most important data in the analysis or monitoring of the UHI. Although high-resolution satellite images (a few meters per a pixel) are valuable data for analysis of the vegetation, we cannot obtain the images periodically for high costs. Moreover, it is difficult to analyze the high-resolution images since the images have the several noises (e.g. shades of buildings, small objects). Data of the Landsat-8 satellite which had launched on Feb. 2013 are freely available from the USGS and are spatial resolution of 30 meters (visible, NIR, SWIR). The aim of this study is to estimate of the mixture ratios of the endmembers from the data in urban area in order to generate vegetation maps in the area. The number of the endmembers is two: "Vegetation" and "Non-vegetation". The Nonlinear Spectral Mixture Model (NSMM) had been proposed by Somers et al. 2009. The NSMM considers second-order interaction (e.g. second reflections) between endmembers. Oyamada et al. 2012 have proposed the topsoil ratio using the unit vectorized reflectance to reduce the difference of brightness (sunny or shade places). In this paper, we have analyzed if NSMM is represented as the influence of second reflections by using the unit vectorized reflectance, and also have analyzed the enhanced NSMM which we had proposed. As the result, Estimation of the vegetation fraction has been influenced by NSMM in a residential region which have several features. Therefore, we have suggested beneficial effect of NSMM for the second reflections.
Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling
Energy Technology Data Exchange (ETDEWEB)
Randall S. Seright
2007-09-30
This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) for existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated
Sarwar, S.; Rashidi, M. M.
2016-07-01
This paper deals with the investigation of the analytical approximate solutions for two-term fractional-order diffusion, wave-diffusion, and telegraph equations. The fractional derivatives are defined in the Caputo sense, whose orders belong to the intervals [0,1], (1,2), and [1,2], respectively. In this paper, we extended optimal homotopy asymptotic method (OHAM) for two-term fractional-order wave-diffusion equations. Highly approximate solution is obtained in series form using this extended method. Approximate solution obtained by OHAM is compared with the exact solution. It is observed that OHAM is a prevailing and convergent method for the solutions of nonlinear-fractional-order time-dependent partial differential problems. The numerical results rendering that the applied method is explicit, effective, and easy to use, for handling more general fractional-order wave diffusion, diffusion, and telegraph problems.
Chemical degassing on EDF units - feed back experience and method
International Nuclear Information System (INIS)
The chemical degassing feasibility of all French units'RCS (Reactor Coolant System) during outages has been proved by tests performed from 2002 to 2004 on PWR units. Chemical degassing has been usually performed on the four 1500 MWe French units since July 2004 and is planned for 2007 on the 34 units of 900 MWe and the 20 units of 1300 MWe. Chemical degassing helps to an optimized shutdown planning management, especially in case of unplanned shutdowns, and helps to limit the thermal stress corrosion of RHR (Residual Heat Remover system) at temperature higher than 120 C degrees by avoiding temperature step extension after bubble collapsing to remove hydrogen increase. Chemical degassing is performed at temperature equal or lower than 80 C degrees, by hydrogen peroxide injection if 3 cm3/kg 2(dissolved) 3/kg. H2O2 calculation can be stoichiometric or increased by 20% depending on the steam generator tubes material and the full power operation duration before the shutdown. Purification flow is adapted to each design type units characteristics to easily manage a hypothetical early oxygenation. Early oxygenation management consists in forecasting the dilution of the VCT (Volume Control Tank) gaseous phase by nitrogen to avoid dangerous H2/O2 gaseous mixture and to obtain oxygenation criteria on VCT. Three kinds of dilution can be used: nitrogen burping with high levels amplitude, continuous nitrogen flushing or discontinuous flushing with a maximal constant VCT level but with pressure variation. (authors)
Method of evaluating chemical shifts of X-ray emission lines in molecules and solids
Lomachuk, Yuriy V.; Titov, Anatoly V.
2013-01-01
Method of evaluating chemical shifts of X-ray emission lines for sufficiently heavy atoms (beginning from period 4 elements) in chemical compounds is developed. This method is based on the pseudopotential model and one-center restoration method (to reconstruct the proper electronic structure in heavy-atom cores). The approximations of instantaneous transition and frozen inner core spinors of the atom are used for derivation of an expression for chemical shift as a difference between mean valu...
Minimizing the Free Energy: A Computer Method for Teaching Chemical Equilibrium Concepts.
Heald, Emerson F.
1978-01-01
Presents a computer method for teaching chemical equilibrium concepts using material balance conditions and the minimization of the free energy. Method for the calculation of chemical equilibrium, the computer program used to solve equilibrium problems and applications of the method are also included. (HM)
Institute of Scientific and Technical Information of China (English)
袁益让
2002-01-01
For combinatorial system of multilayer dynamics of fluids in porous media, the second order and first order upwind finite difference fractional steps schemes applicable to parallel arithmetic are put forward and two-dimensional and three-dimensional schemes are used to form a complete set. Some techniques,such as implicit-explicit difference scheme, calculus of variations, multiplicative commutation rule of difference operators, decomposition of high order difference operators and prior estimates, are adopted. Optimal order estimates in L2 norm are derived to determine the error in the second order approximate solution. This method has already been applied to the numerical simulation of migration-accumulation of oil resources.
Institute of Scientific and Technical Information of China (English)
Yirang YUAN
2006-01-01
For nonlinear coupled system of multilayer dynamics of fluids in porous media, the second order and first order upwind finite difference fractional steps schemes applicable to parallel arithmetic are put forward, and two-dimensional and three-dimensional schemes are used to form a complete set. Some techniques, such as calculus of variations, multiplicative commutation rule of difference operators, decomposition of high order difference operators and prior estimates, are adopted. Optimal order estimates in L2 norm are derived to determine the error in the second order approximate solution.This method has already been applied to the numerical simulation of migration-accumulation of oil resources.
Directory of Open Access Journals (Sweden)
CHEN, Z.
2014-11-01
Full Text Available Impulse noise in power line communication (PLC channel seriously degrades the performance of Multiple-Input Multiple-Output (MIMO system. To remedy this problem, a MIMO detection method based on fractional lower order statistics (FLOS for PLC channel with impulse noise is proposed in this paper. The alpha stable distribution is used to model impulse noise, and FLOS is applied to construct the criteria of MIMO detection. Then the optimal detection solution is obtained by recursive least squares algorithm. Finally, the transmitted signals in PLC MIMO system are restored with the obtained detection matrix. The proposed method does not require channel estimation and has low computational complexity. The simulation results show that the proposed method has a better PLC MIMO detection performance than the existing ones under impulsive noise environment.
International Nuclear Information System (INIS)
Due to the very high activity levels of reprocessing input solutions, the chemical separation of U and Pu required for a reliable mass spectrometric determination of the relevant isotopic compositions can only be performed in a glovebox on diluted material. Depending on the activity of the concentrated liquor, dilutions of up to 40,000 are required to bring the dose rate on contact to acceptable levels for manual handling. These dilutions must be performed inside the highly contaminated environment of the hot cell and are carried out using telemanipulators. The latter operations require considerable skill to prevent accidental contamination of the final dilution. However, even without any contamination, the amount of nuclear material present in the final dilution is very low and represents a considerable challenge to the separation chemistry if time consuming reconcentration of the material by evaporation is to be avoided. This paper describes a simple, robust and efficient method which combines the removal of fission products and the separation of a U and Pu fraction from the concentrated input material prior to despatch to the glovebox. It has the advantage that much larger quantities of U and Pu can be transferred, resulting in improved conditions for further chemical separation, alpha counting and mass spectrometry measurements while reducing the sensitivity to accidental contamination
Hu, S.; Polidori, A.; Arhami, M.; Shafer, M. M.; Schauer, J. J.; Cho, A.; Sioutas, C.
2008-11-01
In this study, two different types of assays were used to quantitatively measure the redox activity of PM and to examine its intrinsic toxicity: 1) in vitro exposure to rat alveolar macrophage (AM) cells using dichlorofluorescin diacetate (DCFH-DA) as the fluorescent probe (macrophage ROS assay), and: 2) consumption of dithiothreitol (DTT) in a cell-free system (DTT assay). Coarse (PM10-2.5), accumulation (PM2.5-0.25), and quasi-ultrafine (quasi-UF, PM0.25) mode particles were collected weekly at five sampling sites in the Los Angeles-Long Beach harbor and at one site near the University of Southern California campus (urban site). All PM samples were analyzed for organic (total and water-soluble) and elemental carbon, organic species, inorganic ions, and total and water-soluble elements. Quasi-UF mode particles showed the highest redox activity at all Long Beach sites (on both a per-mass and per-air volume basis). A significant association (R2=0.61) was observed between the two assays, indicating that macrophage ROS and DTT levels are affected at least partially by similar PM species. Relatively small variation was observed for the DTT measurements across all size fractions and sites, whereas macrophage ROS levels showed more significant ranges across the three different particle size modes and throughout the sites (coefficients of variation, or CVs, were 0.35, 0.24 and 0.53 for quasi-UF, accumulation, and coarse mode particles, respectively). Association between the PM constituents and the redox activity was further investigated using multiple linear regression models. The results showed that OC was the most important component influencing the DTT activity of PM samples. The variability of macrophage ROS was explained by changes in OC concentrations and water-soluble vanadium (probably originating from ship emissions bunker oil combustion). The multiple regression models were used to predict the average diurnal DTT levels as a function of the OC concentration at
Directory of Open Access Journals (Sweden)
A. Cho
2008-06-01
Full Text Available In this study, two different types of assays were used to quantitatively measure the redox activity of PM and to examine its intrinsic toxicity: 1 in vitro exposure to rat alveolar macrophage (AM cells using dichlorofluorescin diacetate (DCFH-DA as the fluorescent probe (macrophage ROS assay, and: 2 consumption of dithiothreitol (DTT in a cell-free system (DTT assay. Coarse (PM10–2.5, accumulation (PM2.5–0.25, and quasi-ultrafine (quasi-UF, PM0.25 mode particles were collected weekly at five sampling sites in the Los Angeles-Long Beach Harbor and at one site near the University of Southern California campus (urban site. All PM samples were analyzed for organic (total and water-soluble and elemental carbon, organic species, inorganic ions, and total and water-soluble elements. Quasi-UF mode particles showed the highest redox activity at all Long Beach sites (on both a per-mass and per-air volume basis. A significant association (R2=0.61 was observed between the two assays, indicating that macrophage ROS and DTT levels are affected at least partially by similar PM species. Relatively small variation was observed for the DTT measurements across all size fractions and sites, whereas macrophage ROS levels showed more significant ranges across the three different particle size modes and throughout the sites (coefficients of variation, or CVs, were 0.35, 0.24 and 0.53 for quasi-UF, accumulation, and coarse mode particles, respectively. Association between the PM constituents and the redox activity was further investigated using multiple linear regression models. The results showed that OC was the most important component influencing the DTT activity of PM samples. The variability of macrophage ROS was explained by changes in OC concentrations and water-soluble vanadium (probably originating from ship emissions – bunker oil combustion. The multiple regression models were used to predict the average diurnal macrophage ROS and DTT levels as a
Method Development to Increase Protein Enrichment During Dry Fractionation of Starch-Rich Legumes
Pelgrom, P.J.M.; Boom, R.M.; Schutyser, M.A.I.
2015-01-01
A facile method was developed to establish milling settings that optimally separate starch granules from protein bodies and cell wall fibres for starch-rich legumes. Optimal separation was obtained for pea, bean, lentil and chickpea when the particle size distribution curve of flour and isolated sta
Calculations of NMR chemical shifts with APW-based methods
Laskowski, Robert; Blaha, Peter
2012-01-01
We present a full potential, all electron augmented plane wave (APW) implementation of first-principles calculations of NMR chemical shifts. In order to obtain the induced current we follow a perturbation approach [Pickard and Mauri, Phys. Rev. BPRBMDO1098-012110.1103/PhysRevB.63.245101 63, 245101 (2001)] and extended the common APW + local orbital (LO) basis by several LOs at higher energies. The calculated all-electron current is represented in traditional APW manner as Fourier series in the interstitial region and with a spherical harmonics representation inside the nonoverlapping atomic spheres. The current is integrated using a “pseudocharge” technique. The implementation is validated by comparison of the computed chemical shifts with some “exact” results for spherical atoms and for a set of solids and molecules with available published data.
Synthesis of Colloidal Ruthenium Nanocatalyst by Chemical Reduction Method
Patharkar, R. G.; S. U. Nandanwar; Chakraborty, M.
2013-01-01
Colloidal ruthenium nanoparticles were prepared by chemical reduction of ruthenium trichloride (RuCl3) using sodium borohydrate (NaBH4) as reducing agent and sodium dodecyl sulfate (SDS) as a stabilizer. Size and size distribution of synthesized colloidal Ru nanoparticles were studied by varying different parameters such as molar ratio (MR) of SDS/RuCl3, NaBH4/RuCl3, effects of different stabilizers, and reducing agents. Prepared nanoparticles were characterized by transmission electron micro...
Realizing NiO nanocrystals from a simple chemical method
Indian Academy of Sciences (India)
Neelabh Srivastava; P C Srivastava
2010-12-01
Nanocrystalline NiO has been prepared successfully by a simple chemical route using NiCl2.6H2O and NaOH aqueous solution at a temperature of 70°C. The prepared material has been characterized from XRD, SEM, and M–H characteristics. It has been found that NiO nanocrystals have been formed which shows a superparamagnetic/superantiferromagnetic behaviour.
CHEMICAL LANGUAGE IS COGNITIVE METHOD AND MAIN INSTRUMENT OF COMMUNICATION
AKMYRZA ZARIPA; AIDYN FARIZAT; SARSENOVA AIDANA
2016-01-01
Chemical language is based on the development of logical thinking in teaching natural sciences, including chemistry. Speech is for opening of semantic connections between substances and changes. The performance of students in chemistry classes and extracurricular activities associated chemistry through the language, through the words of the national language, culture, speech follows General patterns. For students, clarity, accuracy, relevance, consistency and clarity of requirements. Chemistr...
Clemo, T. M.; Ramarao, B.; Kelly, V. A.; Lavenue, M.
2011-12-01
Capture is a measure of the impact of groundwater pumping upon groundwater and surface water systems. The computation of capture through analytical or numerical methods has been the subject of articles in the literature for several decades (Bredehoeft et al., 1982). Most recently Leake et al. (2010) described a systematic way to produce capture maps in three-dimensional systems using a numerical perturbation approach in which capture from streams was computed using unit rate pumping at many locations within a MODFLOW model. The Leake et al. (2010) method advances the current state of computing capture. A limitation stems from the computational demand required by the perturbation approach wherein days or weeks of computational time might be required to obtain a robust measure of capture. In this paper, we present an efficient method to compute capture in three-dimensional systems based upon adjoint states. The efficiency of the adjoint method will enable uncertainty analysis to be conducted on capture calculations. The USGS and INTERA have collaborated to extend the MODFLOW Adjoint code (Clemo, 2007) to include stream-aquifer interaction and have applied it to one of the examples used in Leake et al. (2010), the San Pedro Basin MODFLOW model. With five layers and 140,800 grid blocks per layer, the San Pedro Basin model, provided an ideal example data set to compare the capture computed from the perturbation and the adjoint methods. The capture fraction map produced from the perturbation method for the San Pedro Basin model required significant computational time to compute and therefore the locations for the pumping wells were limited to 1530 locations in layer 4. The 1530 direct simulations of capture require approximately 76 CPU hours. Had capture been simulated in each grid block in each layer, as is done in the adjoint method, the CPU time would have been on the order of 4 years. The MODFLOW-Adjoint produced the capture fraction map of the San Pedro Basin model
Novel pre-treatment and fractionation method for lignocellulosic biomass using ionic liquids
Silva, Sara P. Magalhães da; Lopes, André; Roseiro, Luísa; Bogel-Lukasik, R.
2013-01-01
An efficient lignocellulosic biomass pre-treatment is a crucial step for the valorization of these kind of raw materials. Lignocellulosic biomass is a potentially valuable resource for transformation into biofuels and bio-based products. The use of ionic liquids as media for the biomass pre-treatment is an alternative method that follows the green chemistry concept. This work proposes a new methodology for wheat straw pre-treatment with the ionic liquid (IL) 1-ethyl-3-methylimidazoliu...
Energy Technology Data Exchange (ETDEWEB)
Sabzikar, Farzad, E-mail: sabzika2@stt.msu.edu [Department of Statistics and Probability, Michigan State University, East Lansing, MI 48823 (United States); Meerschaert, Mark M., E-mail: mcubed@stt.msu.edu [Department of Statistics and Probability, Michigan State University, East Lansing, MI 48823 (United States); Chen, Jinghua, E-mail: cjhdzdz@163.com [School of Sciences, Jimei University, Xiamen, Fujian, 361021 (China)
2015-07-15
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.
International Nuclear Information System (INIS)
Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series
DSC method: Determination of amorphous fraction in solid dosage and fragility
Saini, Manoj K.
2015-06-01
We have used Differential Scanning Calorimeter (DSC) method to quantifying the amorphous content in solid dosage of a commonly used drugs namely mephenesin. The glass transition temperature (Tg) of supercooled liquid sample and melting temperature (Tm) of as received sample are found to be 232.2 K and 343.1 K respectively. The "fragility index" of mephenesin has been discussed in detail using the coupling model (m = 250(± 30) - 320βKWW) and compared with acetaminophen and methocarbamol. The sample studied here is found to be kinetically strong in comparison.
Comparison of serum fractionation methods by data independent label-free proteomics
Directory of Open Access Journals (Sweden)
D. Baiwir
2015-12-01
Full Text Available Off-line sample prefractionations applied prior to biomarker discovery proteomics are options to enable more protein identifications and detect low-abundance proteins. This work compared five commercial methods efficiency to raw serum analysis using label-free proteomics. The variability of the protein quantities determined for each process was similar to the unprefractionated serum. A 49% increase in protein identifications and 12.2% of reliable quantification were obtained. A 61 times lower limit of protein quantitation was reached compared to protein concentrations observed in raw serum. The concentrations of detected proteins were confronted to estimated reference values.
Van Berkel, Gary J.
2015-10-06
A system and method for analyzing a chemical composition of a specimen are described. The system can include at least one pin; a sampling device configured to contact a liquid with a specimen on the at least one pin to form a testing solution; and a stepper mechanism configured to move the at least one pin and the sampling device relative to one another. The system can also include an analytical instrument for determining a chemical composition of the specimen from the testing solution. In particular, the systems and methods described herein enable chemical analysis of specimens, such as tissue, to be evaluated in a manner that the spatial-resolution is limited by the size of the pins used to obtain tissue samples, not the size of the sampling device used to solubilize the samples coupled to the pins.
Chemically durable phosphate glasses and a method for their preparation
Day, D.E.; Wilder, J.A. Jr.
The chemical durability of alkali phosphate glasses is improved by incorporation of up to 23 weight percent of nitrogen. A typical phosphate glass contains: 10 to 60 mole % of Li/sub 2/O, Na/sub 2/O or K/sub 2/O; 5 to 40 mole % of BaO or CaO; 0 to 1 to 10 mole % of Al/sub 2/O/sub 3/; and 40 to 70 mole % of P/sub 2/O/sub 5/. Nitrides, such as AlN, are the favored additives.
Chemical and ecological control methods for Epitrix spp.
Directory of Open Access Journals (Sweden)
A. G. S. Cuthbertson
2015-01-01
Full Text Available Very little information exists in regards to the control options available for potato flea beetles, Epitrix spp. This short review covers both chemical and ecological options currently available for control of Epitrix spp. Synthetic pyrethroids are the weapon of choice for the beetles. However, the impetus in integrated pest management is to do timely (early-season applications with something harsh which will give long-term protection at a time when there are not a lot of beneficials in the field. Finding the balance for control of Epitrix spp. is proving difficult.
Klunder, Edgar B.
2011-08-09
The method relates to particle separation from a feed stream. The feed stream is injected directly into the froth zone of a vertical flotation column in the presence of a counter-current reflux stream. A froth breaker generates a reflux stream and a concentrate stream, and the reflux stream is injected into the froth zone to mix with the interstitial liquid between bubbles in the froth zone. Counter-current flow between the plurality of bubbles and the interstitial liquid facilitates the attachment of higher hydrophobicity particles to bubble surfaces as lower hydrophobicity particles detach. The height of the feed stream injection and the reflux ratio may be varied in order to optimize the concentrate or tailing stream recoveries desired based on existing operating conditions.
Applicability of fractional liberation method using tritiated neurotransmitters in neurotoxins study
International Nuclear Information System (INIS)
During the last two decades much progress in neuro physiology was achieved, partly due to successful use of toxins as tools to elucidate structural and physiological functions of neuronal systems. Additionally, the development of the in vitro tritiated neurotransmitters perfusion method made the access of several neuronal transmission steps possible, at only one assay. This procedure maintains an active uptake/release function which is fairly changed by membrane polarization state, ion channel activation and enzymatic activity as well as other still unknown steps involved in neurotransmission. This paper shows the results with some toxins (tetrodotoxin, crotoxin and flaccid paralysis) using 3 H.Dopamine or 3 H.Acetylcholine and K+ 20 mM or Glu 100 μ M. (author)
Chemical methods and phytoremediation of soil contaminated with heavy metals.
Chen, H M; Zheng, C R; Tu, C; Shen, Z G
2000-07-01
The effects of chemical amendments (calcium carbonate (CC), steel sludge (SS) and furnace slag (FS)) on the growth and uptake of cadmium (Cd) by wetland rice, Chinese cabbage and wheat grown in a red soil contaminated with Cd were investigated using a pot experiment. The phytoremediation of heavy metal contaminated soil with vetiver grass was also studied in a field plot experiment. Results showed that treatments with CC, SS and FS decreased Cd uptake by wetland rice, Chinese cabbage and wheat by 23-95% compared with the unamended control. Among the three amendments, FS was the most efficient at suppressing Cd uptake by the plants, probably due to its higher content of available silicon (Si). The concentrations of zinc (Zn), lead (Pb) and Cd in the shoots of vetiver grass were 42-67%, 500-1200% and 120-260% higher in contaminated plots than in control, respectively. Cadmium accumulation by vetiver shoots was 218 g Cd/ha at a soil Cd concentration of 0.33 mg Cd/kg. It is suggested that heavy metal-contaminated soil could be remediated with a combination of chemical treatments and plants. PMID:10819205
Methods for the Determination of Chemical Contaminants in Drinking Water. Training Manual.
Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.
This training manual, intended for chemists and technicians with little or no experience in chemical procedures required to monitor drinking water, covers analytical methods for inorganic and organic chemical contaminants listed in the interim primary drinking water regulations. Topics include methods for heavy metals, nitrate, and organic…
Norton, Stephen; Thao, Do Thi Phurong; Duy, Mai The
2014-01-01
Stephen Norton, Do Thi Phurong Thao and Mai The Duy provide an interesting insight into the teaching of fraction division in Vietnam. The article highlights one of the many teaching strategies available to teachers for building fraction concepts.
Methods of controlling hydrogen fluoride pressure during chemical fabrication processes
Solovyov, Vyacheslav; Wiesmann, Harold
2009-11-24
The present invention is a method for producing a crystalline end-product. The method comprising exposing a fluoride-containing precursor to a hydrogen fluoride absorber under conditions suitable for the conversion of the precursor into the crystalline end-product.
Directory of Open Access Journals (Sweden)
Kyoung Ae Kong
2016-04-01
Full Text Available Background: Smoking is a major modifiable risk factor for premature mortality. Estimating the smoking-attributable burden is important for public health policy. Typically, prevalence- or smoking impact ratio (SIR-based methods are used to derive estimates, but there is controversy over which method is more appropriate for country-specific estimates. We compared smoking-attributable fractions (SAFs of deaths estimated by these two methods. Methods: To estimate SAFs in 2012, we used several different prevalence-based approaches using no lag and 10- and 20-year lags. For the SIR-based method, we obtained lung cancer mortality rates from the Korean Cancer Prevention Study (KCPS and from the United States-based Cancer Prevention Study-II (CPS-II. The relative risks for the diseases associated with smoking were also obtained from these cohort studies. Results: For males, SAFs obtained using KCPS-derived SIRs were similar to those obtained using prevalence-based methods. For females, SAFs obtained using KCPS-derived SIRs were markedly greater than all prevalence-based SAFs. Differences in prevalence-based SAFs by time-lag period were minimal among males, but SAFs obtained using longer-lagged prevalence periods were significantly larger among females. SAFs obtained using CPS-II-based SIRs were lower than KCPS-based SAFs by >15 percentage points for most diseases, with the exceptions of lung cancer and chronic obstructive pulmonary disease. Conclusions: SAFs obtained using prevalence- and SIR-based methods were similar for males. However, neither prevalence-based nor SIR-based methods resulted in precise SAFs among females. The characteristics of the study population should be carefully considered when choosing a method to estimate SAF.
Institute of Scientific and Technical Information of China (English)
靳红梅; 付广青; 常志州; 叶小梅
2013-01-01
Anaerobic digestion treatment effectively degrades the organic matter and causes obvious variations in physical and chemical properties of digested slurries, such as water content, pH, oxidation reduction potential and microbial activities. These changes may influence the chemical fraction of Pb, which is a critical factor in predicting its toxicity, environmental mobility, bioavailability and optimum removal methods. The speciation and phytotoxic effects of lead from sewage sludge and composted manure have been widely studied. There has been no study about the transfer and distribution of Pb during anaerobic digestion of manure slurries. The aim of the present work was to analyze the distribution of Pb in both liquid and solid phase after anaerobic digestion of pig slurries and dairy slurries, and their chemical speciation in solid fraction of digested residuals. The continuous stirred tank reactor (CSTR) at condition of medium temperature [(37 ± 2)℃] was operated for 130 d. Lead in liquid and solid phases of raw materials and digested slurries was analyzed by first passing through a 0.45 µm filter paper. The chemical fractions in digested slurry solids were extracted by BCR method. Results showed that total amount of Pb was decreased 70% and 19% in digested pig slurries (DPS) and dairy slurries (DDS), respectively, , compared with raw slurries. The percentages of Pb in liquid fractions of DPS and DDS were 29%and 17%, which decreased by 17%and 58%. The decrease of Pb in DDS was significantly lower than that in DPS. One reason is that 90%of solids in DDS were discharged during the anaerobic digestion. Another reason is that Pb in digested slurries mainly exists as the solid form. Thus the amount of Pb left in the reactor for dairy manure digestion was significantly lower than that for pig manure digest. Due to the high removal efficiency, easy operation and low treatment cost of heavy metals in solid phase, transformation of liquid phase of heavy metals to the
Synthesis of Colloidal Ruthenium Nanocatalyst by Chemical Reduction Method
Directory of Open Access Journals (Sweden)
R. G. Patharkar
2013-01-01
Full Text Available Colloidal ruthenium nanoparticles were prepared by chemical reduction of ruthenium trichloride (RuCl3 using sodium borohydrate (NaBH4 as reducing agent and sodium dodecyl sulfate (SDS as a stabilizer. Size and size distribution of synthesized colloidal Ru nanoparticles were studied by varying different parameters such as molar ratio (MR of SDS/RuCl3, NaBH4/RuCl3, effects of different stabilizers, and reducing agents. Prepared nanoparticles were characterized by transmission electron microscope (TEM and dynamic light scattering (DLS. Stability of colloidal nanoparticles was detected by Turbiscan. Stable Ru nanoparticles were dispersed on γ-Al2O3 to prepare Ru/γ-Al2O3 catalyst. This catalyst was characterized by X-ray Diffraction (XRD and transmission electron microscope (TEM.
Evaluation of chemical surface treatment methods for mitigation of PWSCC
International Nuclear Information System (INIS)
As part of its mission to propose innovative and safe technologies to mitigate Primary Water Stress Corrosion Cracking (PWSCC) in Pressurized Water Reactors (PWR), EPRI recently initiated a program to evaluate potential new chemical surface treatments that might delay the occurrence of PWSCC such that no failure of components would be observed during their lifetime. Among the initial screening of more than thirty technologies, seven were selected for a more detailed review. The selected technologies were: nickel and nickel alloy plating, organic inhibitors, chromium-based inhibitors, silicon carbide, titanium-based inhibitors, rare earth metal (REM)-based inhibitors and encapsulation. The conclusions of the review of these technologies were that two of them were worth pursuing, titanium-based and REM-based inhibitors, and that evaluating the radiological consequences of injecting these products in the primary system, as well as assessing their efficacy to mitigate PWSCC, should be prioritized as the next required steps in qualification for implementation. (authors)
Chemical recycling of polyhydroxyalkanoates as a method towards sustainable development.
Ariffin, Hidayah; Nishida, Haruo; Hassan, Mohd Ali; Shirai, Yoshihito
2010-05-01
Chemical recycling of bio-based polymers polyhydroxyalkanoates (PHAs) by thermal degradation was investigated from the viewpoint of biorefinery. The thermal degradation resulted in successful transformation of PHAs into vinyl monomers using alkali earth compound (AEC) catalysts. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)s (PHBVs) were smoothly and selectively depolymerized into crotonic (CA) and 2-pentenoic (2-PA) acids at lower degradation temperatures in the presence of CaO and Mg(OH)(2) as catalysts. Obtained CA from 3-hydroxybutyrate sequences in PHBV was copolymerized with acrylic acid to produce useful water-soluble copolymers, poly(crotonic acid-co-acrylic acid) that have high glass-transition temperatures. The copolymerization of CA derived from PHA pyrolysis is an example of cascade utilization of PHAs, which meets the idea of sustainable development. PMID:20408140
Decontamination by water jet, chemical and electrochemical methods
International Nuclear Information System (INIS)
The decontamination tests have been carried out on samples coming from representative specimens from primary circuit of the PWR and on samples coming from the emergency feed water piping of the German BWR (Isar). The oxide found in PWR primary loops can only be removed by a two steps process. The initial embrittling step is particularly effective in hot alkaline permanganate medium. Oxidation by ozone treatment is less effective. The second step involves chemical erosion of the metal in nitrofluoric acid in conjonction with ultrasonic agitation. Among the reagents used, only oxalic acid is suitable for electrolytic decontamination. Among the reagents possible for decontamination of the Isar specimens (ferritic steel lined with hematite) halogenous acid in mixture without or with oxygenated water, sulfuric acid, the formic acid/formaldehyde mixture are chosen. Metal erosion with high pressure jet as well as the decontamination efficiency on parts lined with hematite have made possible to determine the best conditions. 33 figs, 29 refs
International Nuclear Information System (INIS)
Highlights: • A fully automated flow-based modified-BCR extraction method was developed to evaluate the extractable As of soil. • The MSFIA–HG-AFS system included an UV photo-oxidation step for organic species degradation. • The accuracy and precision of the proposed method were found satisfactory. • The time analysis can be reduced up to eight times by using the proposed flow-based BCR method. • The labile As (F1 + F2) was <50% of total As in soil samples from As-contaminated-mining zones. - Abstract: A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L−1 for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013–0.800, 0.011–0.900 and 0.079–1.400 mg L−1 for F1, F2, and F3, respectively. The precision of the automated MSFIA–HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L−1 As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural soil samples from
Energy Technology Data Exchange (ETDEWEB)
Rosas-Castor, J.M. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico); Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Portugal, L.; Ferrer, L. [Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Guzmán-Mar, J.L.; Hernández-Ramírez, A. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico); Cerdà, V. [Group of Analytical Chemistry, Automation and Environment, University of Balearic Islands, Cra. Valldemossa km 7.5, 07122 Palma de Mallorca (Spain); Hinojosa-Reyes, L., E-mail: laura.hinojosary@uanl.edu.mx [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Cd. Universitaria, San Nicolás de los Garza, Nuevo León, C.P. 66451 Nuevo León (Mexico)
2015-05-18
Highlights: • A fully automated flow-based modified-BCR extraction method was developed to evaluate the extractable As of soil. • The MSFIA–HG-AFS system included an UV photo-oxidation step for organic species degradation. • The accuracy and precision of the proposed method were found satisfactory. • The time analysis can be reduced up to eight times by using the proposed flow-based BCR method. • The labile As (F1 + F2) was <50% of total As in soil samples from As-contaminated-mining zones. - Abstract: A fully automated modified three-step BCR flow-through sequential extraction method was developed for the fractionation of the arsenic (As) content from agricultural soil based on a multi-syringe flow injection analysis (MSFIA) system coupled to hydride generation-atomic fluorescence spectrometry (HG-AFS). Critical parameters that affect the performance of the automated system were optimized by exploiting a multivariate approach using a Doehlert design. The validation of the flow-based modified-BCR method was carried out by comparison with the conventional BCR method. Thus, the total As content was determined in the following three fractions: fraction 1 (F1), the acid-soluble or interchangeable fraction; fraction 2 (F2), the reducible fraction; and fraction 3 (F3), the oxidizable fraction. The limits of detection (LOD) were 4.0, 3.4, and 23.6 μg L{sup −1} for F1, F2, and F3, respectively. A wide working concentration range was obtained for the analysis of each fraction, i.e., 0.013–0.800, 0.011–0.900 and 0.079–1.400 mg L{sup −1} for F1, F2, and F3, respectively. The precision of the automated MSFIA–HG-AFS system, expressed as the relative standard deviation (RSD), was evaluated for a 200 μg L{sup −1} As standard solution, and RSD values between 5 and 8% were achieved for the three BCR fractions. The new modified three-step BCR flow-based sequential extraction method was satisfactorily applied for arsenic fractionation in real agricultural
Perrone, Maria Grazia; Zhou, Jun; Malandrino, Mery; Sangiorgi, Giorgia; Rizzi, Cristiana; Ferrero, Luca; Dommen, Josef; Bolzacchini, Ezio
2016-03-01
Recent epidemiological evidence support the hypothesis that health effects from inhalation of air particles are governed by more than just particle mass, since specific chemical components have been identified as important contributors to mortality and hospitality admissions. We studied the chemical composition and the oxidative potential (OP) of total suspended particle (TSP) samples from Milan at two sites with different traffic loads: a site in the low emission zone (LEZ) and a traffic site (TR) outside. Two a-cellular assays; dithiothreitol (OPDTT) and 2‧,7' dichlorofluorescin (OPDCFH) were used to characterize the OP of the soluble fraction of particles. TSP samples from LEZ showed significantly lower concentrations of traffic-related chemical components compared to TR. The decrease in the concentrations from TR to LEZ was maximum for EC, with a LEZ/TR ratio of 0.64 (±0.18), and a significant reduction (p < 0.01) was also observed for PAHs (LEZ/TR = 0.73 ± 0.16), elements (Mn, Cu, Zn, Cd, Pb: LEZ/TR ranged between 0.64 and 0.82), OC (LEZ/TR = 0.85 ± 0.12) and NH4+ (LEZ/TR = 0.92 ± 0.07). OP measures, expressed as OP/m3 or OP/mg, were comparable between sites both for OPDTT and OPDCFH, thus not showing any significant impact of local traffic on OP values at sites. OPDTT and OPDCFH showed contrasting seasonal and daily trends, indicating that the two a-cellular assays gave complementary information on the OP of particles in Milan. The two OP assays resulted to be sensitive to different chemical properties of PM samples. OPDTT correlated positively only with Global Radiation (Spearman's rs = 0.38, p < 0.05), which could be considered as a proxy for high concentrations of secondary oxidizing organics, while OPDCFH was related to various PM chemical species, mainly correlated with total mass (rs = 0.65; p < 0.01), elements (e.g. Zn, rs = 0.67; As, rs = 0.65; p < 0.01) and the sum of sulfate and nitrate (rs = 0.63; p < 0.01), a proxy for secondary aerosol.
Stochastic linear multistep methods for the simulation of chemical kinetics
International Nuclear Information System (INIS)
In this paper, we introduce the Stochastic Adams-Bashforth (SAB) and Stochastic Adams-Moulton (SAM) methods as an extension of the τ-leaping framework to past information. Using the Θ-trapezoidal τ-leap method of weak order two as a starting procedure, we show that the k-step SAB method with k ≥ 3 is order three in the mean and correlation, while a predictor-corrector implementation of the SAM method is weak order three in the mean but only order one in the correlation. These convergence results have been derived analytically for linear problems and successfully tested numerically for both linear and non-linear systems. A series of additional examples have been implemented in order to demonstrate the efficacy of this approach
Stochastic linear multistep methods for the simulation of chemical kinetics
Energy Technology Data Exchange (ETDEWEB)
Barrio, Manuel, E-mail: mbarrio@infor.uva.es [Departamento de Informática, University of Valladolid, Valladolid (Spain); Burrage, Kevin [Department of Computer Science, University of Oxford, Oxford (United Kingdom); School of Mathematical Sciences, Queensland University of Technology, Brisbane (Australia); Burrage, Pamela [School of Mathematical Sciences, Queensland University of Technology, Brisbane (Australia)
2015-02-14
In this paper, we introduce the Stochastic Adams-Bashforth (SAB) and Stochastic Adams-Moulton (SAM) methods as an extension of the τ-leaping framework to past information. Using the Θ-trapezoidal τ-leap method of weak order two as a starting procedure, we show that the k-step SAB method with k ≥ 3 is order three in the mean and correlation, while a predictor-corrector implementation of the SAM method is weak order three in the mean but only order one in the correlation. These convergence results have been derived analytically for linear problems and successfully tested numerically for both linear and non-linear systems. A series of additional examples have been implemented in order to demonstrate the efficacy of this approach.
Perovskite type nanopowders and thin films obtained by chemical methods
Directory of Open Access Journals (Sweden)
Viktor Fruth
2010-09-01
Full Text Available The review presents the contribution of the authors, to the preparation of two types of perovskites, namely BiFeO3 and LaCoO3, by innovative methods. The studied perovskites were obtained as powders, films and sintered bodies. Their complex structural and morphological characterization is also presented. The obtained results have underlined the important influence of the method of preparation on the properties of the synthesized perovskites.
Popescu, Maria-Cristina; Popescu, Carmen-Mihaela; Lisa, Gabriela; Sakata, Yusaku
2011-03-01
The aim of this study is to find the most convenient procedure to make an easy differentiation between various kinds of wood. The wood samples used were: fir (Acer alba), poplar (Populus tremula), lime (Tillia cordata), sycamore (Acer pseudoplatanus), sweet cherry (Prunus avium), hornbeam (Carpinus betulus), walnut (Juglans regia), beech (Fagus sylvatica), oak (Quercus robur). The methods of investigation used were FT-IR spectroscopy, X-ray diffraction and thermogravimetry. By FT-IR spectroscopy, was observed that the ratio values of lignin/carbohydrate IR bands for wood decreases with increasing the average wood density, showing a decrease in lignin content. Also, the calculated values of lignin percentage from the FT-IR spectra are in very good correlation with the values from literature. Following the deconvolution process of the X-ray diffraction patterns, it was found that the degree of crystallinity, the apparent lateral crystallite size, the proportion of crystallite interior chains and cellulose fraction tend to increase with increasing of the wood density. Thermal analysis is able to give information about degradation temperatures for the principal components of different wood samples. The shape of DTG curves depends on the wood species that cause the enlargement of the peaks or the maxima of the decomposition step varies at larger or smaller temperatures ranges. The temperatures and weight loss percentage are particular for each kind of wood. This study showed that analytical methods used have the potential to be important sources of information for a quick evaluation of the chemical composition of wood samples.
Song, Jia; Wang, Lun; Cai, Guobiao; Qi, Xiaoqiang
2015-06-01
Near space hypersonic vehicle model is nonlinear, multivariable and couples in the reentry process, which are challenging for the controller design. In this paper, a nonlinear fractional order proportion integral derivative (NFOPIλDμ) active disturbance rejection control (ADRC) strategy based on a natural selection particle swarm (NSPSO) algorithm is proposed for the hypersonic vehicle flight control. The NFOPIλDμ ADRC method consists of a tracking-differentiator (TD), an NFOPIλDμ controller and an extended state observer (ESO). The NFOPIλDμ controller designed by combining an FOPIλDμ method and a nonlinear states error feedback control law (NLSEF) is to overcome concussion caused by the NLSEF and conversely compensate the insufficiency for relatively simple and rough signal processing caused by the FOPIλDμ method. The TD is applied to coordinate the contradiction between rapidity and overshoot. By attributing all uncertain factors to unknown disturbances, the ESO can achieve dynamic feedback compensation for these disturbances and thus reduce their effects. Simulation results show that the NFOPIλDμ ADRC method can make the hypersonic vehicle six-degree-of-freedom nonlinear model track desired nominal signals accurately and fast, has good stability, dynamic properties and strong robustness against external environmental disturbances.
Deciding which chemical mixtures risk assessment methods work best for what mixtures
International Nuclear Information System (INIS)
The most commonly used chemical mixtures risk assessment methods involve simple notions of additivity and toxicological similarity. Newer methods are emerging in response to the complexities of chemical mixture exposures and effects. Factors based on both science and policy drive decisions regarding whether to conduct a chemical mixtures risk assessment and, if so, which methods to employ. Scientific considerations are based on positive evidence of joint toxic action, elevated human exposure conditions or the potential for significant impacts on human health. Policy issues include legislative drivers that may mandate action even though adequate toxicity data on a specific mixture may not be available and risk assessment goals that impact the choice of risk assessment method to obtain the amount of health protection desired. This paper discusses three important concepts used to choose among available approaches for conducting a chemical mixtures risk assessment: (1) additive joint toxic action of mixture components; (2) toxicological interactions of mixture components; and (3) chemical composition of complex mixtures. It is proposed that scientific support for basic assumptions used in chemical mixtures risk assessment should be developed by expert panels, risk assessment methods experts, and laboratory toxicologists. This is imperative to further develop and refine quantitative methods and provide guidance on their appropriate applications. Risk assessors need scientific support for chemical mixtures risk assessment methods in the form of toxicological data on joint toxic action for high priority mixtures, statistical methods for analyzing dose-response for mixtures, and toxicological and statistical criteria for determining sufficient similarity of complex mixtures
Directory of Open Access Journals (Sweden)
Shi-Yong Gao
2015-03-01
Full Text Available Sauromatum giganteum (Engl. Cusimano & Hett Tuber are used in Chinese folklore medicine for treatment of neoplasms. However, the claim has not been scientifically validated. The aim of the study is to screen the antitumor bioactive fraction of Sauromatum giganteum (Engl. Cusimano & Hett Tuber and sensitive tumor cell lines using a cytotoxicity assay in vitro and tumor transplantation method in vivo, to support its use in folk medicine. The petroleum ether fraction, chloroform fraction, ethyl acetate fraction, n-butanol fraction and water fraction were successively extracted by turn by the maceration under reflux assay. Screening of antitumor bioactive fraction and sensitive cell lines were measured by MTT assay and the serum pharmacology method, and in vivo the antitumor activities of the active fraction was evaluated by using S180 or H22 tumor-bearing mice model and Kunming mice. The active constituents of ethyl acetate fraction of Sauromatum giganteum (Engl. Cusimano & Hett were characterized by UPLC-TOF-MS. Compared with control groups, mice serum containing ethyl acetate fraction had a inhibition effect on SMMC-7721 cell, SGC-7901 cell, MCF-7 cell, HeLa cell, A549 cell, HT-29, and MDA-MB-231, respectively, but mice serum containing other four fractions had no different with that of control group. The inhibition capabilities of mice serum containing ethyl acetate fraction on the seven cell lines in descending order is SGC-7901 > SMMC-7721 > MCF-7 > HT-29 > A549 > HeLa > MDA-MB-231. In vivo the inhibition rate of 106, 318, 954 mg/kg·d ethyl acetate fraction dry extract to sarcoma S180 is 15.22%, 26.15% and 40.24%, respectively, and life prolonging rate to hepatoma H22 is 33.61%, 40.16% and 55.74%. A total of 14 compounds were identified in the ethyl acetate fraction of Sauromatum giganteum (Engl. Cusimano & Hett. The results of the experimental studies proved the antitumor activity of Sauromatum giganteum (Engl. Cusimano & Hett and supported
International Nuclear Information System (INIS)
We present a new, nondestructive, method for determining chemical potentials in Monte Carlo and molecular dynamics simulations. The method estimates a value for the chemical potential such that one has a balance between fictitious successful creation and destruction trials in which the Monte Carlo method is used to determine success or failure of the creation/destruction attempts; we thus call the method a detailed balance method. The method allows one to obtain estimates of the chemical potential for a given species in any closed ensemble simulation; the closed ensemble is paired with a ''natural'' open ensemble for the purpose of obtaining creation and destruction probabilities. We present results for the Lennard-Jones system and also for an embedded atom model of liquid palladium, and compare to previous results in the literature for these two systems. We are able to obtain an accurate estimate of the chemical potential for the Lennard-Jones system at higher densities than reported in the literature
Recent advances in chemical engineering. Tracers and tracing methods
International Nuclear Information System (INIS)
The first congress on 'tracers and tracing methods' has taken place in Nancy in November 1998. It has been a successful national event with more than 100 participants and 65 presentations. The applications of radiotracers in different industries have been studied. The target participants were the researchers, engineers and technologists of various industrial and research sectors
Predictive performance of the Vitrigel-eye irritancy test method using 118 chemicals.
Yamaguchi, Hiroyuki; Kojima, Hajime; Takezawa, Toshiaki
2016-08-01
We recently developed a novel Vitrigel-eye irritancy test (EIT) method. The Vitrigel-EIT method is composed of two parts, i.e., the construction of a human corneal epithelium (HCE) model in a collagen vitrigel membrane chamber and the prediction of eye irritancy by analyzing the time-dependent profile of transepithelial electrical resistance values for 3 min after exposing a chemical to the HCE model. In this study, we estimated the predictive performance of Vitrigel-EIT method by testing a total of 118 chemicals. The category determined by the Vitrigel-EIT method in comparison to the globally harmonized system classification revealed that the sensitivity, specificity and accuracy were 90.1%, 65.9% and 80.5%, respectively. Here, five of seven false-negative chemicals were acidic chemicals inducing the irregular rising of transepithelial electrical resistance values. In case of eliminating the test chemical solutions showing pH 5 or lower, the sensitivity, specificity and accuracy were improved to 96.8%, 67.4% and 84.4%, respectively. Meanwhile, nine of 16 false-positive chemicals were classified irritant by the US Environmental Protection Agency. In addition, the disappearance of ZO-1, a tight junction-associated protein and MUC1, a cell membrane-spanning mucin was immunohistologically confirmed in the HCE models after exposing not only eye irritant chemicals but also false-positive chemicals, suggesting that such false-positive chemicals have an eye irritant potential. These data demonstrated that the Vitrigel-EIT method could provide excellent predictive performance to judge the widespread eye irritancy, including very mild irritant chemicals. We hope that the Vitrigel-EIT method contributes to the development of safe commodity chemicals. Copyright © 2015 The Authors. Journal of Applied Toxicology published by John Wiley & Sons Ltd. PMID:26472347
A Schematic Method for Sustainable Material Selection of Toxic Chemicals in Design and Manufacturing
Yuan, Chris Yingchun; David Dornfeld
2010-01-01
Toxic chemicals used in product design and manufacturing are grave concerns due to their toxic impact on human health. Implementing sustainable material selection strategies on toxic chemicals can substantially improve the sustainability of products in both design and manufacturing processes. In this paper, a schematic method is presented for characterizing and benchmarking the human health impact of toxic chemicals, as a visual aid to facilitate decision-making in the material selection proc...
Stanka HERJAVEC; Majdak, Ana; Tupajić, Pavica; Redžepović, Sulejman; Orlić, Sandi
2003-01-01
Changes in chemical composition and sensory properties caused by chemical and microbiological methods of deacidification in Moslavac (syn. Furmint) wines were investigated. Alcoholic fermentation of Moslavac musts was carried out with two different strains of the yeasts Saccharomyces paradoxus. There were no marked differences in chemical composition among the wines. Compared to the control microbiological deacidification of wines by Oenococcus oeni resulted in a complete decomposition of mal...
A new ultrasonic method to detect chemical additives in branded milk
Indian Academy of Sciences (India)
S Mohanan; P G Thomas Panicker; Lilly Iype; M Laila; I Domini; R G Bindu
2002-09-01
A new ultrasonic method – thermoacoustic analysis – is reported for the detection of the added chemical preservatives in branded milk. The nature of variation and shift in the thermal response of the acoustic parameters speciﬁc acoustic impedance, adiabatic compressibility and Rao’s speciﬁc sound velocity for different samples of branded milk as compared to the chemical added pure milk are explained as due to the presence of chemicals in these branded samples.
International Nuclear Information System (INIS)
The determination of states of radionuclides forms in soils is one principal factor for establishment of both directivity and velocity of radionuclide migration processes. In the work for study of these processes the fractional leaching method has been used. In the method the soil was sequentially treated by following reactants: water; 1M acetate-ammoniac buffers; 1M chloric acid and M2 chloric acid. For quantitative evaluation on long-lived radionuclides transfer into leaching products after soil treatment by the reagents the radioisotope comprehensive determination scheme was worked out. The evaluation test for plutonium-239+240, cesium-137, strontium-90 scheme was carried out on the soils taken from territories adjoining to 'Lira' site. Obtained data show that radiochemical yield for strontium-90 is varying from 65 to 83 %, cesium-137 - from 80 to 84 %, plutonium-239+240 from 25 to 32 %. Application of the methodical complex allows to obtain quantitative evaluation of soil samples leaching rate, on this base the series of real radionuclide mobility (sum of water-soluble and exchange forms) are considered
Directory of Open Access Journals (Sweden)
Swathi SundarRaj
2015-01-01
Full Text Available Autologous fat grafting for soft tissue reconstruction is challenged by unpredictable long-term graft survival. Fat derived stromal vascular fraction (SVF is gaining popularity in tissue reconstruction as SVF-enriched fat grafts demonstrate improved engraftment. SVF also has potential in regenerative medicine for remodeling of ischemic tissues by promoting angiogenesis. Since SVF cells do not require culture expansion, attempts are being made to develop automated devices to isolate SVF at the point of care. We report development of a closed, automated system to process up to 500 mL lipoaspirate using cell size-dependent filtration technology. The yield of SVF obtained by automated tissue digestion and filtration (1.17 ± 0.5 × 105 cells/gram was equivalent to that obtained by manual isolation (1.15 ± 0.3 × 105; p = 0.8, and the viability of the cells isolated by both methods was greater than 90%. Cell composition included CD34+CD31− adipose stromal cells, CD34+CD31+ endothelial progenitor cells, and CD34−CD31+ endothelial cells, and their relative percentages were equivalent to SVF isolated by the manual method. CFU-F capacity and expression of angiogenic factors were also comparable with the manual method, establishing proof-of-concept for fully automated SVF isolation, suitable for use in reconstructive surgeries and regenerative medicine applications.
Splitting methods for three-dimensional bio-chemical transport
Sommeijer, Ben; Kok, Jan
1996-01-01
Splitting methods for the time integration of three-dimensional transport-chemistry models offer interesting prospects: second-order accuracy can be combined with sufficient stability, and the amount of implicitness can be reduced to a manageable level. Furthermore, exploiting the parallelization and vectorization features of the algorithm, a realistic simulation with many species over long time intervals becomes feasible. As an alternative to the usual splitting functions, such as co-ordinat...
Methods for chemical analysis of water and wastes
Energy Technology Data Exchange (ETDEWEB)
1979-03-01
This manual provides test procedures approved for the monitoring of water supplies, waste discharges, and ambient waters, under the Safe Drinking Water Act, the National Pollutant Discharge Elimination System, and Ambient Monitoring Requirements of Section 106 and 208 of Public Law 92-500. The test methods have been selected to meet the needs of federal legislation and to provide guidance to laboratories engaged in the protection of human health and the aquatic environment.
Simulation of Chemical Reactors using the Least-Squares Spectral Element method
Sporleder, Federico
2011-01-01
The least–squares spectral element method is a relatively novel method that can be used to solve any well–posed problem. It has been extensively used in computational fluid dynamics, and in recent years has been applied in the field of chemical engineering. This work focuses on the use of the least–squares spectral element method for the simulation of chemical reactors from a general point of view. The document presents an analysis on the common challenges that chemical reactor models pose an...
Recycling of poly(ethylene terephthalate – A review focusing on chemical methods
Directory of Open Access Journals (Sweden)
B. Geyer
2016-07-01
Full Text Available Recycling of poly(ethylene terephthalate (PET is of crucial importance, since worldwide amounts of PETwaste increase rapidly due to its widespread applications. Hence, several methods have been developed, like energetic, material, thermo-mechanical and chemical recycling of PET. Most frequently, PET-waste is incinerated for energy recovery, used as additive in concrete composites or glycolysed to yield mixtures of monomers and undefined oligomers. While energetic and thermo-mechanical recycling entail downcycling of the material, chemical recycling requires considerable amounts of chemicals and demanding processing steps entailing toxic and ecological issues. This review provides a thorough survey of PET-recycling including energetic, material, thermo-mechanical and chemical methods. It focuses on chemical methods describing important reaction parameters and yields of obtained reaction products. While most methods yield monomers, only a few yield undefined low molecular weight oligomers for impaired applications (dispersants or plasticizers. Further, the present work presents an alternative chemical recycling method of PET in comparison to existing chemical methods.
DEFF Research Database (Denmark)
Zhang, Fang; Aaltonen, Jaakko; Tian, Fang;
2009-01-01
using DSC in order to link the physical and chemical stability with molecular mobility. Chemical stability was studied with high-performance liquid chromatography (HPLC). Results obtained from the current study revealed that the solubility of amorphous forms prepared by both methods was enhanced...
International Nuclear Information System (INIS)
In this study, an improved method for calculating the effective delayed neutron fraction of a core with a few collapsed energy groups has been developed. To accurately calculate the effective delayed neutron fraction of a core using the conventional method, a structure with several energy groups is needed for the fast energy region in order to reflect the difference in the fission spectra for prompt fission neutrons and delayed neutrons. On the other hand, a structure with only a few energy groups is needed for the criticality evaluation. Thus, the calculation cost increases for the effective delayed neutron fraction calculations owing to the need for a large number of energy groups. To solve this problem, in the present study, the error mechanism for the effective delayed neutron fraction calculation using a structure with only a few energy groups was studied, and it was found that the error results from the collapse of the fission spectra after the cell calculations without adjoint flux weighting. In addition, an improved method for the collapse fission spectra with an adjoint flux obtained by one-point calculation was developed. Using the proposed method, the effective delayed neutron fraction can be estimated with sufficient accuracy using a structure consisting of only a few collapsed energy groups. This result will contribute to reducing the calculation cost and/or improving the accuracy of effective delayed neutron fraction calculations. (author)
Directory of Open Access Journals (Sweden)
Mauricas Mykolas
2005-09-01
Full Text Available Abstract Background Presently available flow cytometric methods of bromodeoxyuridine (BrdUrd labelling do not provide information on the cell cycle time (TC and the growth fraction (GF. In this paper, we describe a novel and simple method to estimate TC and GF from flow cytometric analysis of a single tumour sample after BrdUrd labelling. Methods The proposed method is based on two assumptions: (1 the number of labelled cells traversing the cell cycle per unit time is constant and (2 the total number of labelled cells is constant throughout the cycle, provided that cells produced after division are excluded. The total numbers of labelled divided G1 cells, labelled divided S cells, labelled undivided S cells, and labelled undivided G2 cells were obtained for DNA histograms of BrdUrd-positive cells in a collected sample. These cell numbers were used to write equations to determine the durations of cell cycle phases, TC and GF. To illustrate the application of the proposed formulae, cell cycle kinetic parameters were analysed in solid SL2 tumours growing in DBA/2 mice and in human T-leukaemia Jurkat cells in culture. Results The suitability of the proposed method for estimating durations of the cell cycle phases, TC and GF was demonstrated. TC in SL2 tumours was found to be relatively constant at 4 and 10 days after tumour implantation (20.3 ± 1.1 h and 21.6 ± 0.9 h, respectively. GF in tumours at day 10 was lower than GF at day 4 (54.2 ± 7.7% vs. 79.2 ± 5.9%, p = 0.0003. Approximate values of TC and GF of cultured Jurkat cells were 23.9 h and 79.3%, respectively. Conclusion The proposed method is relatively simple and permits estimation of the cell cycle parameters, including TC and GF, from a single tumour sample after labelling with BrdUrd. We have shown that this method may be useful in preclinical studies, allowing estimation of changes in GF during growth of murine tumours. Experiments with human Jurkat cells suggest that the proposed
International Nuclear Information System (INIS)
The unconstrained lattice parameters and volume fractions of γ' for a low misfit nickel based superalloy were evaluated using X-ray diffraction techniques. Extraction techniques were used to provide unconstrained γ' powders for both water quenched and slow cooled samples that were aged at 760 deg. C for 0, 25, 50, 100, and 200 h. The external standard method was used to determine the volume fraction for the unaged water quenched sample and the slow cooled sample aged for 200 h. These two extremes in processing conditions provided an increase in the total volume fraction of γ'.
Quality control of chemical heat treatment by the fractography method
International Nuclear Information System (INIS)
A fractographic investigation is carried out of fracture of a nitrided layer of 38KhMYuA steel and of cemented and cyanided layers of 12KhM3A steel. It is established that a fracture of the nitrided layer consists of three zones of crystalline facets: 1) a surface zone of fine crystalline facets located in a single plane and having the appearance of a white band (Σ-phase zone); 2) zone of acicular facets whose presence is due to the break-down of the carbonitride phase; 3) zone of large facets of boundary breakdown. The fractures of cemented and cyanided samples consist of multiple fine facets of multi-face shapes. It has been found that the depth and the microstructure of a diffusion layer in steel after chemothermal processing can be most rapidly and objectively evaluated by the fractographic method
Comparison of different physico-chemical methods for the removal of toxicants from landfill leachate
International Nuclear Information System (INIS)
Our work was focused on investigation of different treatment procedures for the removal of toxic fractions from a landfill leachate, because sometimes the existing treatment in biological sequencing batch reactor (SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two toxicity tests (activated sludge and Vibrio fischeri). The existing SBR (HRT = 1.9 days) removed 46-78% of COD and 96-73% of NH4+-N. Experiments were conducted with three landfill leachate samples expressing significant difference in concentrations of pollutants and with low BOD5/COD ratio (0.06/0.01/0.03). The applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch system with different concentration of PAC the most effective was the highest addition (50.0 g L-1) where 63-92% of COD was removed followed by significant reduction in toxicity to V. fischeri. In the column experiments with clinoptilolite 45/93/100% of NH4+-N as well as 25/32/39% of COD removal was attained. The removal efficiency for metals followed the sequence Cr > Zn > Cd > Ni. The procedure with zeolite was the second most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio Fe2+:H2O2 = 1.0:10.0 assured 70-85% removal of COD but it only slightly reduced the toxicity.
Comparison of different physico-chemical methods for the removal of toxicants from landfill leachate
Energy Technology Data Exchange (ETDEWEB)
Cotman, Magda, E-mail: magda.cotman@ki.si [National Institute of Chemistry, Hajdrihova 19, SI-1001 Ljubljana (Slovenia); Zgajnar Gotvajn, Andreja [University of Ljubljana, Faculty of Chemistry and Chemical Technology (Slovenia)
2010-06-15
Our work was focused on investigation of different treatment procedures for the removal of toxic fractions from a landfill leachate, because sometimes the existing treatment in biological sequencing batch reactor (SBR) is not efficient enough, leading to a hazardous environmental impact of the present persistent and toxic compounds. The efficiency of the procedures used was monitored by chemical analyses and two toxicity tests (activated sludge and Vibrio fischeri). The existing SBR (HRT = 1.9 days) removed 46-78% of COD and 96-73% of NH{sub 4}{sup +}-N. Experiments were conducted with three landfill leachate samples expressing significant difference in concentrations of pollutants and with low BOD{sub 5}/COD ratio (0.06/0.01/0.03). The applied methods were air stripping, adsorption to activated carbon and zeolite clinoptilolite and Fenton oxidation. Air stripping at pH 11 was a viable treatment option for the removal of ammonia nitrogen (up to 94%) and reduction of toxicity to microorganisms. In the adsorption experiments in batch system with different concentration of PAC the most effective was the highest addition (50.0 g L{sup -1}) where 63-92% of COD was removed followed by significant reduction in toxicity to V. fischeri. In the column experiments with clinoptilolite 45/93/100% of NH{sub 4}{sup +}-N as well as 25/32/39% of COD removal was attained. The removal efficiency for metals followed the sequence Cr > Zn > Cd > Ni. The procedure with zeolite was the second most efficient one regarding reduction of toxicity to both organisms. Fenton oxidation at molar ratio Fe{sup 2+}:H{sub 2}O{sub 2} = 1.0:10.0 assured 70-85% removal of COD but it only slightly reduced the toxicity.
Speciation of hydroxy-aluminum solutions by wet chemical and aluminum-27 NMR methods
International Nuclear Information System (INIS)
Partially neutralized Al solutions with OH/Al molar (n∼) ratios ranging from 0.25 to 2.5 were studied employing 27Al nuclear magnetic resonance spectroscopy and the ferron-timed colorimetric assay. The monomeric Al concentrations (Al/sub a/) estimated by the ferron assay were consistently higher than the actual concentration determined by NMR spectroscopy. The differences between the methods indicate the presence of a small polymer which reacts rapidly with ferron and is erroneously assigned to the monomeric Al fraction. The polymeric Al component (Al/sub b/) estimated by the ferron method could be partitioned into a more rapidly reacting fraction (∂1 h) and a slowly reacting fraction (> 1 h). The amount of Al associated with the rapidly reacting polymeric fraction corresponded to the amount of [AlO4 Al12(OH)24(H2O)12]7+ polymer directly determined by NMR spectroscopy. The slower reacting component of the Al/sub b/ fraction is believed to be a polymer of the hexameric ring morphology. Direct NMR measurements provided evidence for specific adsorption of Al13 to a cation exchange resin and differential precipitation kinetics of this polymer with added sulfate. These data indicate that characterizing hydroxy Al solutions without direct measurements can lead to erroneous interpretations concerning the distribution between monomeric and polymeric Al and the nature and types of polymeric Al present
Perez-Rea, Daysi; Bergenståhl, Björn; Nilsson, Lars
2015-06-01
We have investigated methods of starch dissolution with the aim of finding an optimum method to completely dissolve starch granules to form a molecularly dissolved starch solution without degradation of the polymers. Glycogen was used as a model molecule for amylopectin, to identify the dissolution conditions under which the degradation of the polymers was limited or not present. Dissolution was performed in water with temperatures up to 200 °C, facilitated by the use of heating in an autoclave or a microwave oven, or in dimethyl sulfoxide (DMSO) at 100 °C. Waxy maize starch was chosen due to its high content of amylopectin and very low content of amylose. The degree of starch dissolution under different conditions was determined enzymatically. The effect of different dissolution conditions on the molar mass and root-mean-square radius of the polymers was determined with asymmetrical flow field-flow fractionation coupled to multi-angle light scattering and differential refractive index (AF4-MALS-dRI) detectors under aqueous conditions. The results suggest that reliable and accurate size separation and characterization of amylopectin can be obtained by dissolution of starch granules in an aqueous environment at 140 °C by autoclaving or in DMSO at 100 °C. The results also clearly show an upper limit for heat treatment of starch, above which degradation cannot be avoided. PMID:25925852