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Sample records for human elemental composition

  1. Factors influencing trace element composition in human teeth

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, L. [Los Alamos National Lab., NM (United States); Iyengar, G.V. [Biomineral Sciences International, Inc., Bethesda, MD (United States)

    1997-12-01

    The authors recently compiled and reviewed the literature published in or after 1978 for 45 major, minor, and trace elements in human teeth as a part of an International Atomic Energy Agency (IAEA) study. The purpose of this paper is to discuss the various factors that influence the concentration levels of certain trace elements in human teeth. The sampling practices and analytical techniques that are applicable for trace element analysis are also discussed. It is also our intention to identify reference range of values, where data permit such conclusions. The scrutiny was designed to identify only the healthy permanent teeth, and values from teeth with fillings, caries, or periodontal diseases were eliminated.

  2. Variation in elemental composition of human teeth and its application for feasible species identification.

    Science.gov (United States)

    Nganvongpanit, Korakot; Buddhachat, Kittisak; Piboon, Promporn; Euppayo, Thippaporn; Mahakkanukrauh, Pasuk

    2017-02-01

    Identifying human remains is a primary task in forensic science. In this study, we propose a possible new technique, handheld X-ray fluorescence (HHXRF), for determining whether a suspected tooth is an authentic human tooth. A total of 444 teeth obtained from 111 human skulls (male=62, female=49) aged between 30-67 years (51.81±8.37 years) were used as subjects. The teeth were scanned by HHXRF to acquire their elemental profile. Differences in elemental composition were analyzed for different tooth positions (numbers 1-32), between crown and root, and between sexes (male and female); also, the proportion of elements in relation to different human ages was examined. Teeth from 20 different animal species, serving as non-human teeth samples, were used to distinguish between human and non-human teeth through a stepwise discriminant analysis. Our results revealed that different tooth positions, different regions (crown and root) of a tooth, and different sexes demonstrated disparities in the proportion of several elements. The accuracy rate of predicting sex based on the elemental profile of human teeth was 65.5%. Likewise, a dissimilar distribution of elements between human and non-human teeth was observed, leading to a high degree of correctness of 83.2% for distinguishing them. In conclusion, elemental analysis by HHXRF could serve as a promising candidate tool for identifying human teeth in forensic science, but is ineffective for sex determination.

  3. Elemental composition of human teeth with emphasis on trace constituents: a review

    Energy Technology Data Exchange (ETDEWEB)

    Sachs, W H

    1978-04-01

    Literature covered by the current review is based on a search of Chemical Abstracts, 1917 through 1975. Early studies, pre-dating 1940, are referenced primarily for historical interest. Emphasis is on the micro-constituents of human teeth, those present at concentrations less than a few tenths of a percent by weight. Within this category of data, we have been primarily concerned with the radiochemically stable nuclides. The important relationship between caries and trace elements is covered only insofar as carious teeth exhibit properties with respect to trace element composition that differ from normal teeth. Having made these disclaimers, we note that an attempt has been made to cover the literature exhaustively; although some important results have undoubtedly been overlooked. It is our hope, however, that sufficient material has been included in this review to facilitate further recovery of data by interested individuals. In Chapter 1, analytical techniques that have been employed in this field are briefly presented; discussion centers on problems associated with preparation of specimens for analysis. Chapter 2 is devoted to topical coverage of data on the inorganic composition of teeth. An element-by-element tabulation of concentration data is provided, our statistical analysis of selected data explained, and evidence concerning several major factors thought to influence dental composition evaluated. These include provenance, age, sex, distribution, and tooth type/intermouth variation.

  4. Difference of histology and elemental composition of the cervical enamels among human permanent teeth

    Institute of Scientific and Technical Information of China (English)

    Masashi TAKAHASHI; Shin-Ichi GOTO; Kazuhisa MORI; Izumi MATAGA

    2008-01-01

    The purpose of this study is to clarify the dif-ference of histology and elemental composition of the cer-vical enamels among the human permanent teeth. The re-ground surfaces at the cervical enamels of them were observed under scanning electron microscopy (SEM). The contents of seven elements were analyzed quantita-tively with electron probe microanalyzer (EPMA). The widths of the rod sections at the cervical enamels were larger than those at the cuspal enamels. The rod sections at the mesial cervical enamels in the incisors were more obscure and more decayed by acid solution than those in the premolars and molars. The calcium and phosphorus contents of the cervical enamels were significantly lower than those of the cuspal enamels. The carbon content of the cervical enamels was significantly higher than that of the cuspal enamels. The calcium and phosphorus contents of the cervical enamels were the significantly highest in the premolars. The carbon and sodium contents of the cer-vical enamels were significantly highest in the premolars. It is thought that the calcification level is lower, while the content of organic matter is higher at the cervical enamels than those at the cuspal enamels. It is considered that the sodium causes high calcification.

  5. Composition and distribution of elements and ultrastructural topography of a human cardiac calculus.

    Science.gov (United States)

    Cheng, Ching-Li; Chang, Hsiao-Huang; Huang, Pei-Jung; Chu, Yu-Ting; Lin, Shan-Yang

    2013-04-01

    Trace elements (TEs) may contribute to the formation of calculi or stones or be involved in the aetiopathogenesis of stone diseases. The compositions and spatial distribution of elements from the inner nucleus to outer crust of the cardiac calculus were investigated by energy-dispersive X-ray fluorescence (EDXRF) spectrometer. The surface topograph, distribution map of elements, elemental and chemical compositions were also determined by environmental scanning electron microscope (ESEM)-energy-dispersive X-ray (EDX) analysis. Twenty-five elements were identifiable from 18 positions on the cardiac calculus by EDXRF spectrometer, in which the highest concentrations of toxic TEs (Ni, Pt, Hg, Sn, Pb, W, Au, Al, Si) and higher levels of essential TEs (Ca, Sr, Cr, P) were detected. A moderate positive Pearson's correlation between TEs concentrations of Mg, Ca or P and location differences from centre to periphery in the cardiac calculus was observed. A positive correlation was also found for Ca/Zn and Ca/Cu, indicating the gradual increase of calcium concentration from inner nucleus to outer crust of cardiac calculus. The drop-like nodules/crystals on the surface of petrous part of cardiac calculus were observed from ESEM analysis. ESEM-EDX analysis determined the calculus to be predominantly composed of calcium hydroxyapatite and cholesterol, as indicated by the petrous surface and drop-like nodules/crystals, respectively. This composition was confirmed using a portable Raman analyser. The spatial distribution analysis indicated a gradual increase in Mg, P and Ca concentrations from the inner nucleus to the outer crust of the cardiac calculus. The major chemical compositions of calcium hydroxyapatite and cholesterol were detected on this cardiac calculus.

  6. Vesta's Elemental Composition

    Science.gov (United States)

    Prettyman, T. H.; Beck, A. W.; Feldman, W. C.; Lawrence, D. J.; McCoy, T. J.; McSween, H. Y.; Mittlefehldt, D. W.; Peplowski, P. N.; Raymond, C. A.; Reedy, R. C.; Russell, C. T.; Titus, T. N.; Toplis, M. J.; Yamashita, N.

    2014-01-01

    Many lines of evidence (e.g. common geochemistry, chronology, O-isotope trends, and the presence of different HED rock types in polymict breccias) indicate that the howardite, eucrite, and diogenite (HED) meteorites originated from a single parent body. Meteorite studies show that this protoplanet underwent igneous differentiation to form a metallic core, an ultramafic mantle, and a basaltic crust. A spectroscopic match between the HEDs and 4 Vesta along with a plausible mechanism for their transfer to Earth, perhaps as chips off V-type asteroids ejected from Vesta's southern impact basin, supports the consensus view that many of these achondritic meteorites are samples of Vesta's crust and upper mantle. The HED-Vesta connection was put to the test by the NASA Dawn mission, which spent a year in close proximity to Vesta. Measurements by Dawn's three instruments, redundant Framing Cameras (FC), a Visible-InfraRed (VIR) spectrometer, and a Gamma Ray and Neutron Detector (GRaND), along with radio science have strengthened the link. Gravity measurements by Dawn are consistent with a differentiated, silicate body, with a dense Fe-rich core. The range of pyroxene compositions determined by VIR overlaps that of the howardites. Elemental abundances determined by nuclear spectroscopy are also consistent with HED-compositions. Observations by GRaND provided a new view of Vesta inaccessible by telescopic observations. Here, we summarize the results of Dawn's geochemical investigation of Vesta and their implications.

  7. Elemental composition of Malawian rice.

    Science.gov (United States)

    Joy, Edward J M; Louise Ander, E; Broadley, Martin R; Young, Scott D; Chilimba, Allan D C; Hamilton, Elliott M; Watts, Michael J

    2016-07-20

    Widespread potential dietary deficiencies of calcium (Ca), iron (Fe), iodine (I), selenium (Se) and zinc (Zn) have been identified in Malawi. Several deficiencies are likely to be compounded by high phytic acid (PA) consumption. Rice (Oryza sativa) is commonly consumed in some Malawian populations, and its mineral micronutrient content is important for food security. The considerable irrigation requirements and flooded conditions of paddy soils can also introduce or mobilise potentially toxic elements including arsenic (As), cadmium (Cd) and lead (Pb). The aim of this study was to determine the mineral composition of rice sampled from farmers' fields and markets in Malawi. Rice was sampled from 18 extension planning areas across Malawi with 21 white (i.e. polished) and 33 brown samples collected. Elemental composition was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Arsenic speciation was performed using high-performance liquid chromatography (HPLC)-ICP-MS. Concentration of PA was determined using a PA-total phosphorus assay. Median total concentrations (mg kg(-1), dry weight) of elements important for human nutrition in brown and white rice, respectively, were: Ca = 66.5 and 37.8; Cu = 3.65 and 2.49; Fe = 22.1 and 7.2; I = 0.006 and Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied greatly, and this was likely due to contamination of rice samples with soil. Risk of As, Cd or Pb toxicity due to rice consumption in Malawi appears to be minimal.

  8. Analysis of composite structural elements

    Directory of Open Access Journals (Sweden)

    A. Baier

    2010-12-01

    Full Text Available Purpose: The themes of the study are composite structural components. For this purpose have been designed and built several research positions.Design/methodology/approach: Using different structural materials to build new device components requires multiple tests of the components. Research posts were designed in the advanced graphical program CAx Siemens NX 7.5. Analysed samples were made from the glass fibre, aramid and carbon of various weights. Due to the specific use of composite materials it focuses on the elements in the form of plates and flat bars. For the examination of experimental strain gauge technique was used bead, the force sensor and displacement sensor. The experimental methods were compared with computer simulation using the FEM.Findings: The aim of this study was to determine the basic material constants and a comparison of the experimental method and the method of computer simulation.Research limitations/implications: Change the number of layers and how to connect the laminate with the steel plate changes mechanical properties of the structural component.Practical implications: The ultimate result will be knowledge on the different forms of laminates, such as material properties, the stresses in all layers, strain and comparing the results obtained by two methods.Originality/value: The expected outcome of the study will be the composition and method of joining composite laminate with a steel plate to the possible application in the repair and construction of structural elements of freight wagons.

  9. Composite oxygen ion transport element

    Science.gov (United States)

    Chen, Jack C.; Besecker, Charles J.; Chen, Hancun; Robinson, Earil T.

    2007-06-12

    A composite oxygen ion transport element that has a layered structure formed by a dense layer to transport oxygen ions and electrons and a porous support layer to provide mechanical support. The dense layer can be formed of a mixture of a mixed conductor, an ionic conductor, and a metal. The porous support layer can be fabricated from an oxide dispersion strengthened metal, a metal-reinforced intermetallic alloy, a boron-doped Mo.sub.5Si.sub.3-based intermetallic alloy or combinations thereof. The support layer can be provided with a network of non-interconnected pores and each of said pores communicates between opposite surfaces of said support layer. Such a support layer can be advantageously employed to reduce diffusion resistance in any type of element, including those using a different material makeup than that outlined above.

  10. A Comparative Analyses of Granulometry, Mineral Composition and Major and Trace Element Concentrations in Soils Commonly Ingested by Humans

    Directory of Open Access Journals (Sweden)

    Veronica M. Ngole-Jeme

    2015-07-01

    Full Text Available This study compared the granulometric properties, mineralogical composition and concentrations of major and trace element oxides of commonly ingested soils (geophagic soil collected from different countries with a view of understanding how varied they may be in these properties and to understand the possible health implications of ingesting them. Soil samples were collected from three different countries (South Africa, Swaziland and Democratic Republic of Congo (DRC and their granulometric properties, concentrations of major and trace element oxides as well as mineralogical composition determined. Differences were observed in the granulometric properties of geophagic soil from the three different countries with most of them having <20% clay content. The soils also showed varied degrees of weathering with values of Chemical Index of Alteration (CIA and Chemical Index of Weathering (CIW being between 60% and 99.9% respectively. The mineral assemblages of the soils from South Africa and Swaziland were dominated by the primary minerals quartz and feldspar whereas soils from DRC had more of kaolinite, a secondary mineral than primary minerals. Soils from DRC were associated with silt, clay, Al2O3, and CIA unlike most samples from South Africa which were associated with SiO2, sand, K2O, CaO, and MgO. The soils from Swaziland were closely associated with silt, H2O and Fe2O3(t. These associations reflect the mineralogy of the samples. These soils are not likely to serve as nutrient supplements because of the low concentrations of the nutrient elements contained. The coarse texture of the samples may also result in dental destruction during mastication. Sieving of the soils before ingestion to remove coarse particles is recommended to reduce the potential health threat associated with the ingestion of coarse-textured soils.

  11. Composite structure of auxin response elements.

    Science.gov (United States)

    Ulmasov, T; Liu, Z B; Hagen, G; Guilfoyle, T J

    1995-10-01

    The auxin-responsive soybean GH3 gene promoter is composed of multiple auxin response elements (AuxREs), and each AuxRE contributes incrementally to the strong auxin inducibility to the promoter. Two independent AuxREs of 25 bp (D1) and 32 bp (D4) contain the sequence TGTCTC. Results presented here show that the TGTCTC element in D1 and D4 is required but not sufficient for auxin inducibility in carrot protoplast transient expression assays. Additional nucleotides upstream of TGTCTC are also required for auxin inducibility. These upstream sequences showed constitutive activity and no auxin inducibility when part or all of the TGTCTC element was mutated or deleted. In D1, the constitutive element overlaps the 5' portion of TGTCTC; in D4, the constitutive element is separated from TGTCTC. An 11-bp element in D1, CCTCGTGTCTC, conferred auxin inducibility to a minimal cauliflower mosaic virus 35S promoter in transgenic tobacco seedlings as well as in carrot protoplasts (i.e., transient expression assays). Both constitutive elements bound specifically to plant nuclear proteins, and the constitutive element in D1 bound to a recombinant soybean basic leucine zipper transcription factor with G-box specificity. To demonstrate further the composite nature of AuxREs and the ability of the TGTCTC element to confer auxin inducibility, we created a novel AuxRE by placing a yeast GAL4 DNA binding site adjacent to the TGTCTC element. Expression of a GAL4-c-Rel transactivator in the presence of this novel AuxRE resulted in auxin-inducible expression. Our results indicate that at least some AuxREs have a composite structure consisting of a constitutive element adjacent to a conserved TGTCTC element that confers auxin inducibility.

  12. Berry fruits: compositional elements, biochemical activities, and the impact of their intake on human health, performance, and disease.

    Science.gov (United States)

    Seeram, Navindra P

    2008-02-13

    An overwhelming body of research has now firmly established that the dietary intake of berry fruits has a positive and profound impact on human health, performance, and disease. Berry fruits, which are commercially cultivated and commonly consumed in fresh and processed forms in North America, include blackberry ( Rubus spp.), black raspberry ( Rubus occidentalis), blueberry ( Vaccinium corymbosum), cranberry (i.e., the American cranberry, Vaccinium macrocarpon, distinct from the European cranberry, V. oxycoccus), red raspberry ( Rubus idaeus) and strawberry ( Fragaria x ananassa). Other berry fruits, which are lesser known but consumed in the traditional diets of North American tribal communities, include chokecherry ( Prunus virginiana), highbush cranberry ( Viburnum trilobum), serviceberry ( Amelanchier alnifolia), and silver buffaloberry ( Shepherdia argentea). In addition, berry fruits such as arctic bramble ( Rubus articus), bilberries ( Vaccinuim myrtillus; also known as bog whortleberries), black currant ( Ribes nigrum), boysenberries ( Rubus spp.), cloudberries ( Rubus chamaemorus), crowberries ( Empetrum nigrum, E. hermaphroditum), elderberries ( Sambucus spp.), gooseberry ( Ribes uva-crispa), lingonberries ( Vaccinium vitis-idaea), loganberry ( Rubus loganobaccus), marionberries ( Rubus spp.), Rowan berries ( Sorbus spp.), and sea buckthorn ( Hippophae rhamnoides), are also popularly consumed in other parts of the world. Recently, there has also been a surge in the consumption of exotic "berry-type" fruits such as the pomegranate ( Punica granatum), goji berries ( Lycium barbarum; also known as wolfberry), mangosteen ( Garcinia mangostana), the Brazilian açaí berry ( Euterpe oleraceae), and the Chilean maqui berry ( Aristotelia chilensis). Given the wide consumption of berry fruits and their potential impact on human health and disease, conferences and symposia that target the latest scientific research (and, of equal importance, the dissemination of

  13. Including supplementary elements in a compositional biplot

    Science.gov (United States)

    Daunis-i-Estadella, J.; Thió-Henestrosa, S.; Mateu-Figueras, G.

    2011-05-01

    The biplot is a widely and powerful methodology used with multidimensional data sets to describe and display the relationships between observations and variables in an easy way. Compositional data are vectors with positive components, whose sum is constant because they represent a relative contribution of different parts to a whole; due to this property standard biplots cannot be performed with compositional data, instead of a previous transformation of the data is performed. In this paper, we extend the compositional biplot defined by Aitchison and Greenacre (2002), in order to include in the display supplementary elements which are not used in the definition of the compositional biplot. Different types of supplementary elements are considered: supplementary parts of the composition, supplementary continuous variables external to the composition, supplementary categorical variables and supplementary observations. The projection of supplementary parts of the composition is done by means of the equivalence of clr and lr biplots. The other supplementary projections are done by classical methodology. An application example with a real geological data is included.

  14. Spring-forward in composite plate elements

    NARCIS (Netherlands)

    Wijskamp, Sebastiaan; Lamers, E.A.D.; Akkerman, Remko; Banabic, D.

    2005-01-01

    Spring-forward is a distortion of corner sections in continuous fibre reinforced composite products. The linear thermoelastic prediction for the spring-forward of single curved geometries is incorporated in a FE formulation for plate elements in order to simulate the spring-forward of doubly curved

  15. Spring-forward in composite plate elements

    NARCIS (Netherlands)

    Wijskamp, S.; Lamers, E.A.D.; Akkerman, R.

    2005-01-01

    Spring-forward is a distortion of corner sections in continuous fibre reinforced composite products. The linear thermoelastic prediction for the spring-forward of single curved geometries is incorporated in a FE formulation for plate elements in order to simulate the spring-forward of doubly curved

  16. Nuclear fuel elements having a composite cladding

    Science.gov (United States)

    Gordon, Gerald M.; Cowan, II, Robert L.; Davies, John H.

    1983-09-20

    An improved nuclear fuel element is disclosed for use in the core of nuclear reactors. The improved nuclear fuel element has a composite cladding of an outer portion forming a substrate having on the inside surface a metal layer selected from the group consisting of copper, nickel, iron and alloys of the foregoing with a gap between the composite cladding and the core of nuclear fuel. The nuclear fuel element comprises a container of the elongated composite cladding, a central core of a body of nuclear fuel material disposed in and partially filling the container and forming an internal cavity in the container, an enclosure integrally secured and sealed at each end of said container and a nuclear fuel material retaining means positioned in the cavity. The metal layer of the composite cladding prevents perforations or failures in the cladding substrate from stress corrosion cracking or from fuel pellet-cladding interaction or both. The substrate of the composite cladding is selected from conventional cladding materials and preferably is a zirconium alloy.

  17. Finite elements modeling of delaminations in composite laminates

    DEFF Research Database (Denmark)

    Gaiotti, m.; Rizzo, C.M.; Branner, Kim;

    2011-01-01

    The application of composite materials in many structures poses to engineers the problem to create reliable and relatively simple methods, able to estimate the strength of multilayer composite structures. Multilayer composites, like other laminated materials, suffer from layer separation, i.e., d...... by finite elements using different techniques. Results obtained with different finite element models are compared and discussed.......The application of composite materials in many structures poses to engineers the problem to create reliable and relatively simple methods, able to estimate the strength of multilayer composite structures. Multilayer composites, like other laminated materials, suffer from layer separation, i...... of the buckling strength of composite laminates containing delaminations. Namely, non-linear buckling and post-buckling analyses are carried out to predict the critical buckling load of elementary composite laminates affected by rectangular delaminations of different sizes and locations, which are modelled...

  18. 23 Elemental Composition of Suspended Particulate Matter ...

    African Journals Online (AJOL)

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    coarse and fine particulate matter fractions at the higher height. The elements Cu, Zn, ... dense population, high density housing, the ..... could be in the vapor phase at the higher height. .... precipitation from a remote background site in. India.

  19. PROXIMATE AND ELEMENTAL COMPOSITION OF WHITE GRUBS

    African Journals Online (AJOL)

    DR. AMINU

    1.23% (protein, lipids, carbohydrates and ash) and (moisture content) 34.01 ± 1.00%. The lipid and protein ... advised. Keywords: White grubs, Proximate Analysis, Essential element, Nutrient .... of important enzyme reactions: the oxidation of.

  20. Finite element modeling of the human pelvis

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, B.

    1995-11-01

    A finite element model of the human pelvis was created using a commercial wire frame image as a template. To test the final mesh, the model`s mechanical behavior was analyzed through finite element analysis and the results were displayed graphically as stress concentrations. In the future, this grid of the pelvis will be integrated with a full leg model and used in side-impact car collision simulations.

  1. 20 Elemental Composition and Sources of Atmospheric Particulate ...

    African Journals Online (AJOL)

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    Elemental Composition and Sources of Atmospheric Particulate Matter in Dar es Salaam,. Tanzania ... adverse health effects associated with ambient ... and is at about 1 km to the Indian Ocean. A ..... concentration ratio was around 2, which is.

  2. MASS CONCENTRATIONS AND ELEMENTAL COMPOSITION OF ...

    African Journals Online (AJOL)

    Preferred Customer

    concentration surpassed the WHO safe guideline value of 150 µg/m3 and 79 % of .... Kotebe Waste Water Treatment Plant site (KWWT) is located in the eastern part ... Each filter paper was oven dried, weighed and stored in desiccator before and ... and blank filter samples were analyzed for elements using standard method.

  3. Composition and Trace Element Content of Coal in Taiwan

    Institute of Scientific and Technical Information of China (English)

    蔡龙贻

    2002-01-01

    Researches on trace elements in coal and their influence on environment and human health were introduced. Some 4 coal samples were taken from Taiwan to test the content of trace elements. The author holds that a further study is needed for understanding the modes of occurrence of elements during the deposition and coalification stage in the studying area.

  4. Mixed isoparametric finite element models of laminated composite shells

    Science.gov (United States)

    Noor, A. K.; Andersen, C. M.

    1977-01-01

    Mixed shear-flexible isoparametric elements are presented for the stress and free vibration analysis of laminated composite shallow shells. Both triangular and quadrilateral elements are considered. The 'generalized' element stiffness, consistent mass, and consistent load coefficients are obtained by using a modified form of the Hellinger-Reissner mixed variational principle. Group-theoretic techniques are used in conjunction with computerized symbolic integration to obtain analytic expressions for the stiffness, mass and load coefficients. A procedure is outlined for efficiently handling the resulting system of algebraic equations. The accuracy of the mixed isoparametric elements developed is demonstrated by means of numerical examples, and their advantages over commonly used displacement elements are discussed.

  5. HTGR spent fuel composition and fuel element block flow

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, C.J.; Holder, N.D.; Pierce, V.H.; Robertson, M.W.

    1976-07-01

    The High-Temperature Gas-Cooled Reactor (HTGR) utilizes the thorium-uranium fuel cycle. Fully enriched uranium fissile material and thorium fertile material are used in the initial reactor core and for makeup fuel in the recycle core loadings. Bred /sup 233/U and unburned /sup 235/U fissile materials are recovered from spent fuel elements, refabricated into recycle fuel elements, and used as part of the recycle core loading along with the makeup fuel elements. A typical HTGR employs a 4-yr fuel cycle with approximately one-fourth of the core discharged and reloaded annually. The fuel element composition, including heavy metals, impurity nuclides, fission products, and activation products, has been calculated for discharged spent fuel elements and for reload fresh fuel and recycle fuel elements for each cycle over the life of a typical HTGR. Fuel element compositions are presented for the conditions of equilibrium recycle. Data describing compositions for individual reloads throughout the reactor life are available in a detailed volume upon request. Fuel element block flow data have been compiled based on a forecast HTGR market. Annual block flows are presented for each type of fuel element discharged from the reactors for reprocessing and for refabrication.

  6. Major element composition of Luna 20 glasses.

    Science.gov (United States)

    Warner, J.; Reid, A. M.; Ridley, W. I.; Brown, R. W.

    1972-01-01

    Ten per cent of the 50 to 150-micron size fraction of Luna 20 soil is glass. A random suite of 270 of these glasses has been analyzed by electron microprobe techniques. The major glass type forms a strong cluster around a mean value corresponding to Highland basalt (anorthositic gabbro) with 70% normative feldspar. Minor glass groups have the compositions of mare basalts and of low-K Fra Mauro type basalts. The glass data indicate that Highland basalt is the major rock type in the highlands north of Mare Fecunditatis.

  7. Elemental composition of game meat from Austria.

    Science.gov (United States)

    Ertl, Kathrin; Kitzer, Roland; Goessler, Walter

    2016-06-01

    Concentrations of 26 elements (B, Na, Mg, P, S, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Cd, Sb, Ba, Hg, Pb, U) in wild game meat from Austria were analysed using an inductively coupled plasma mass spectrometer. All investigated animals were culled during the hunting season 2012/2013, including 10 chamois (Rupicapra rupicapra), 9 hare (Lepus europaeus), 10 pheasant (Phasianus colchicus), 10 red deer (Cervus elaphus), 12 roe deer (Capreolus capreolus) and 10 wild boar (Sus scrofa). In 19 out of 61 meat samples lead concentrations were higher than 0.1 mg/kg, the maximum limit in meat as set by the European Commission (Regulation EC No 1881/2006), which is most likely caused by ammunition residues. Especially, pellet shot animals and chamois show a high risk for lead contamination. Despite ammunition residues all investigated muscle samples show no further health risk with respect to metal contamination.

  8. The Elemental Compositions of Extrasolar Planetesimals

    CERN Document Server

    Jura, M

    2013-01-01

    Evidence is now compelling that most externally-polluted white dwarfs derive their heavy atoms by accretion from asteroids - the building blocks of rocky planets. Optical and ultraviolet spectroscopy of a small sample of suitable white dwarf stars shows that to zeroth order, the accreted extrasolar parent bodies compositionally resemble bulk Earth. (1) Extrasolar planetesimals are at least 85% by mass composed of O, Mg, Si and Fe. (2) Compared to the Sun, C is often deficient, usually by at least a factor of 10 and therefore comprises less than 1% of an extrasolar planetesimal's mass. At least to-date, C has never been found to be enhanced as would be expected if carbon-rich planetesimals have formed. (3) While there may be individual exceptions, considered as a whole, the population of extrasolar asteroids accreted onto a well-defined sample of local white dwarf stars is less than 1% water by mass.

  9. A comparison of the effects of prosthetic and commercially pure metals on retrieved human fibroblasts: the role of surface elemental composition.

    Science.gov (United States)

    Mostardi, R A; Kovacik, M W; Ramsier, R D; Bender, E T; Finefrock, J M; Bear, T F; Askew, M J

    2010-02-01

    The most common clinical cause of long-term failure in total joint replacement surgery is inflammatory aseptic osteolysis; a condition in which bone surrounding the prosthetic implant, and to which the implant is attached, is resorbed, rendering the artificial device loose and painful. Historically, the severity of this bone resorptive process has been thought to be predominately attributed to the size and shape of wear-debris particles, particularly the metallic particulates that interact biologically/immunologically with cells in the joint. Because the cytotoxic reactions are the result of interactions between the cells and the surfaces of the particulates, it is not clear in the realm of orthopedics to what extent different surface stoichiometric ratios contribute to instigating bioreactive or cytotoxic cellular responses that can lead to aseptic osteolysis. Using energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), this study presents data and analyses concerning the respective bulk and surface stoichiometric ratios of two commercially pure metal micro-particulates (tantalum and titanium), two prosthetic F75 cobalt-chromium-molybdenum alloy micro-particulates, and prosthetic F136 titanium-aluminum-vanadium alloy micro-particulates, each containing elements common to total joint replacement surgery. Cell culture viability data from four volunteer donors are also presented, which suggest that micro-particulates containing large percentages of surface titanium and aluminum can cause moderate cellular toxicity, and micro-particulates containing large percentages of surface cobalt can result in extremely severe cellular toxicity. This work further suggests that surface analysis techniques, such as XPS, are essential to determine surface elemental characterization of metallic materials prior to interpreting cellular response results.

  10. Finite element based micro-mechanics modeling of textile composites

    Science.gov (United States)

    Glaessgen, E. H.; Griffin, O. H., Jr.

    1995-01-01

    Textile composites have the advantage over laminated composites of a significantly greater damage tolerance and resistance to delamination. Currently, a disadvantage of textile composites is the inability to examine the details of the internal response of these materials under load. Traditional approaches to the study fo textile based composite materials neglect many of the geometric details that affect the performance of the material. The present three dimensional analysis, based on the representative volume element (RVE) of a plain weave, allows prediction of the internal details of displacement, strain, stress, and failure quantities. Through this analysis, the effect of geometric and material parameters on the aforementioned quantities are studied.

  11. FINITE ELEMENT IMPLEMENTATION OF DELAMINATION IN COMPOSITE PLATES

    Directory of Open Access Journals (Sweden)

    Milan Žmindák

    2012-12-01

    Full Text Available Modelling of composite structures by finite element (FE codes to effectively model certain critical failure modes such as delamination is limited. Previous efforts to model delamination and debonding failure modes using FE codes have typically relied on ad hoc failure criteria and quasi-static fracture data. Improvements to these modelling procedures can be made by using an approach based on fracture mechanics. A study of modelling delamination using the finite element code ANSYS was conducted. This investigation demonstrates the modelling of composites through improved delamination modelling. Further developments to this approach may be improved.

  12. Comparative studies of elemental composition in leaves and flowers of Catharanthus roseus growing in Bangladesh

    Directory of Open Access Journals (Sweden)

    Shahin Aziz

    2016-01-01

    Conclusions: The elemental composition in both leaves and flowers of C. roseus were found to be different. Therefore, different parts of this medicinal plant are enriched in some micro and macro nutrients like Fe, Ca, Na, K, Zn, which are very important for biological metabolic system as well as human health.

  13. Finite element analysis of human joints

    Energy Technology Data Exchange (ETDEWEB)

    Bossart, P.L.; Hollerbach, K.

    1996-09-01

    Our work focuses on the development of finite element models (FEMs) that describe the biomechanics of human joints. Finite element modeling is becoming a standard tool in industrial applications. In highly complex problems such as those found in biomechanics research, however, the full potential of FEMs is just beginning to be explored, due to the absence of precise, high resolution medical data and the difficulties encountered in converting these enormous datasets into a form that is usable in FEMs. With increasing computing speed and memory available, it is now feasible to address these challenges. We address the first by acquiring data with a high resolution C-ray CT scanner and the latter by developing semi-automated method for generating the volumetric meshes used in the FEM. Issues related to tomographic reconstruction, volume segmentation, the use of extracted surfaces to generate volumetric hexahedral meshes, and applications of the FEM are described.

  14. The Human Element and Autonomous Ships

    Directory of Open Access Journals (Sweden)

    Sauli Ahvenjärvi

    2016-09-01

    Full Text Available The autonomous ship technology has become a “hot” topic in the discussion about more efficient, environmentally friendly and safer sea transportation solutions. The time is becoming mature for the introduction of commercially sensible solutions for unmanned and fully autonomous cargo and passenger ships. Safety will be the most interesting and important aspect in this development. The utilization of the autonomous ship technology will have many effects on the safety, both positive and negative. It has been announced that the goal is to make the safety of an unmanned ship better that the safety of a manned ship. However, it must be understood that the human element will still be present when fully unmanned ships are being used. The shore-based control of a ship contains new safety aspects and an interesting question will be the interaction of manned and unmanned ships in the same traffic area. The autonomous ship technology should therefore be taken into account on the training of seafarers. Also it should not be forgotten that every single control algorithm and rule of the internal decision making logic of the autonomously navigating ship has been designed and coded by a human software engineer. Thus the human element is present also in this point of the lifetime navigation system of the autonomous ship.

  15. Finite Element Analysis of a Natural Fiber (Maize Composite Beam

    Directory of Open Access Journals (Sweden)

    D. Saravana Bavan

    2013-01-01

    Full Text Available Natural fiber composites are termed as biocomposites or green composites. These fibers are green, biodegradable, and recyclable and have good properties such as low density and low cost when compared to synthetic fibers. The present work is investigated on the finite element analysis of the natural fiber (maize composite beam, processed by means of hand lay-up method. Composite beam material is composed of stalk-based fiber of maize and unsaturated polyester resin polymer as matrix with methyl ethyl ketone peroxide (MEKP as a catalyst and Cobalt Octoate as a promoter. The material was modeled and resembled as a structural beam using suitable assumption and analyzed by means of finite element method using ANSYS software for determining the deflection and stress properties. Morphological analysis and X-ray diffraction (XRD analysis for the fiber were examined by means of scanning electron microscope (SEM and X-ray diffractometer. From the results, it has been found that the finite element values are acceptable with proper assumptions, and the prepared natural fiber composite beam material can be used for structural engineering applications.

  16. Finite element modeling of consolidation of composite laminates

    Institute of Scientific and Technical Information of China (English)

    Xiangqiao Yan

    2006-01-01

    Advanced fiber reinforced polymer composites have been increasingly applied to various structural corn-ponents.One of the important processes to fabricate high performance laminated composites is an autoclave assisted prepreg lay-up.Since the quality of laminated composites is largely affected by the cure cycle,selection of an appropriate cure cycle for each application is important and must be opti-mized.Thus.some fundamental model of the consolidation and cure processes is necessary for selecting suitable param-eters for a specific application.This article is concerned with the "flow-compaction" model during the autoclave process-ing of composite materials.By using a weighted residual method,two-dimensional finite element formulation for the consolidation process of thick thermosetting composites is presented and the corresponding finite element code is developed.Numerical examples.including comparison of the present numerical results with one-dimensional and two-dimensional analytical solutions,are given to illustrate the accuracy and effectiveness of the proposed finite element formulation.In addition,a consolidation simulation of As4/3501-6 graphite/epoxy laminate is carried out and compared with the experimental results available in the literature.

  17. Design of engineered cementitious composites for ductile seismic resistant elements

    Science.gov (United States)

    Kanda, Tetsushi

    This dissertation focuses on designing Engineered Cementitious Composite (ECC) to achieve high performance seismic resistant elements. To attain this goal, three major tasks have been accomplished. Task 1 aims at achieving new ECCs involving low cost fiber, which often involve fiber rupture in crack bridging, thus named as "Fiber Rupture Type ECC". Achieving the new ECC requires a new practical and comprehensive composite design theory. For this theory, single fiber behavior was first investigated. Specifically, fiber rupture in composite and chemical bond in fiber/matrix interface were experimentally examined and mathematically modeled. Then this model for single fiber behavior was implemented into a proposed bridging law, a theoretical model for relationship between fiber bridging stress of composite and Crack Opening Displacement (COD). This new bridging law was finally employed to establish a new composite design theory. Task 2 was initiated to facilitate structural interpretation of ECC's material behavior investigated in Task 1. For this purpose, uniaxial tensile behavior, one of the most important ECC's properties, was theoretically characterized with stress-strain relation from micromechanics view point. As a result, a theory is proposed to express ECC's tensile stress-strain relation in terms of micromechanics parameters of composites, such as bond strengths. Task 3 primarily demonstrates an integrated design scheme for ductile seismic elements that covers from micromechanics in single fiber level to structural design tool, such as with non-linear FEM analysis. The significance of this design scheme is that the influences of ECC's microstructure on element's structural performance is quantitatively captured. This means that a powerful tool is obtained for tailoring constitutive micromechanics parameters in order to maximize structural performance of elements. While the tool is still preliminary, completing this tool in future studies will enable one to

  18. Comprehensive model for predicting elemental composition of coal pyrolysis products

    Energy Technology Data Exchange (ETDEWEB)

    Ricahrds, Andrew P. [Brigham Young Univ., Provo, UT (United States); Shutt, Tim [Brigham Young Univ., Provo, UT (United States); Fletcher, Thomas H. [Brigham Young Univ., Provo, UT (United States)

    2017-04-23

    Large-scale coal combustion simulations depend highly on the accuracy and utility of the physical submodels used to describe the various physical behaviors of the system. Coal combustion simulations depend on the particle physics to predict product compositions, temperatures, energy outputs, and other useful information. The focus of this paper is to improve the accuracy of devolatilization submodels, to be used in conjunction with other particle physics models. Many large simulations today rely on inaccurate assumptions about particle compositions, including that the volatiles that are released during pyrolysis are of the same elemental composition as the char particle. Another common assumption is that the char particle can be approximated by pure carbon. These assumptions will lead to inaccuracies in the overall simulation. There are many factors that influence pyrolysis product composition, including parent coal composition, pyrolysis conditions (including particle temperature history and heating rate), and others. All of these factors are incorporated into the correlations to predict the elemental composition of the major pyrolysis products, including coal tar, char, and light gases.

  19. Galerkin finite element scheme for magnetostrictive structures and composites

    Science.gov (United States)

    Kannan, Kidambi Srinivasan

    The ever increasing-role of magnetostrictives in actuation and sensing applications is an indication of their importance in the emerging field of smart structures technology. As newer, and more complex, applications are developed, there is a growing need for a reliable computational tool that can effectively address the magneto-mechanical interactions and other nonlinearities in these materials and in structures incorporating them. This thesis presents a continuum level quasi-static, three-dimensional finite element computational scheme for modeling the nonlinear behavior of bulk magnetostrictive materials and particulate magnetostrictive composites. Models for magnetostriction must deal with two sources of nonlinearities-nonlinear body forces/moments in equilibrium equations governing magneto-mechanical interactions in deformable and magnetized bodies; and nonlinear coupled magneto-mechanical constitutive models for the material of interest. In the present work, classical differential formulations for nonlinear magneto-mechanical interactions are recast in integral form using the weighted-residual method. A discretized finite element form is obtained by applying the Galerkin technique. The finite element formulation is based upon three dimensional eight-noded (isoparametric) brick element interpolation functions and magnetostatic infinite elements at the boundary. Two alternative possibilities are explored for establishing the nonlinear incremental constitutive model-characterization in terms of magnetic field or in terms of magnetization. The former methodology is the one most commonly used in the literature. In this work, a detailed comparative study of both methodologies is carried out. The computational scheme is validated, qualitatively and quantitatively, against experimental measurements published in the literature on structures incorporating the magnetostrictive material Terfenol-D. The influence of nonlinear body forces and body moments of magnetic origin

  20. Major element composition of glasses in three Apollo 15 soils.

    Science.gov (United States)

    Reid, A. M.; Warner, J.; Ridley, W. I.; Brown, R. W.

    1972-01-01

    Approximately 180 glasses in each of three Apollo 15 soils have been analyzed for nine elements. Cluster analysis techniques allow the recognition of preferred glass compositions that are equated with parent rock compositions. Green glass rich in Fe and Mg, poor in Al and Ti may be derived from deep-seated pyroxenitic material now present at the Apennine Front. Fra Mauro basalt (KREEP) is most abundant in the LM soil and is tentatively identified as ray material from the Aristillus-Autolycus area. Highland basalt (anorthositic gabbro), believed to be derived from the lunar highlands, has the same composition as at other landing sites, but is less abundant. The Apennine Front is probably not true highland material but may contain a substantial amount of material with the composition of Fra Mauro basalt, but lacking the high-K content.

  1. Characterization of Multiple Delaminated Composite by Finite Element

    Directory of Open Access Journals (Sweden)

    SUDIP DEY

    2011-09-01

    Full Text Available In this paper, a finite element method is employed to investigate the natural frequencies of twisted rotating composite turbine blades subject to multiple delamination. The turbine blade is idealized as a shallow conical shell model with low aspect ratio. The formulation is based on Mindlin’s theory, QR iteration and multi-point constraint algorithm for moderate rotational speeds neglecting Coriolis effect. Computer codes are developed and the numerical results obtained for multiple delaminated graphite-epoxy cross-ply composite shallow conical shells are the first known non-dimensional frequencies for the type of analyses carried out here.

  2. Primordial heavy elements in composite dark matter models

    CERN Document Server

    Khlopov, M Yu

    2008-01-01

    A widely accepted viewpoint is to consider candidates for cosmological dark matter as neutral and weakly interacting particles, as well as to consider only light elements in the pregalactic chemical composition. It is shown that stable charged leptons and quarks can exist and, hidden in elusive atoms, play the role of dark matter. The inevitable consequence of realistic scenarios with such composite atom-like dark matter is existence of significant or even dominant fraction of "atoms", binding heavy -2 charged particles and He-4 nuclei. Being alpha-particles with shielded electric charge, such atoms catalyse a new path of nuclear transformations in the period of Big Bang Nucleosynthesis, which result in primordial heavy elements. The arguments are given, why such scenario escapes immediate contradiction with observations and challenges search for heavy stable charged particles in cosmic rays and at accelerators.

  3. Better Finite-Element Analysis of Composite Shell Structures

    Science.gov (United States)

    Clarke, Gregory

    2007-01-01

    A computer program implements a finite-element-based method of predicting the deformations of thin aerospace structures made of isotropic materials or anisotropic fiber-reinforced composite materials. The technique and corresponding software are applicable to thin shell structures in general and are particularly useful for analysis of thin beamlike members having open cross-sections (e.g. I-beams and C-channels) in which significant warping can occur.

  4. Compositional data analysis for elemental data in forensic science.

    Science.gov (United States)

    Campbell, Gareth P; Curran, James M; Miskelly, Gordon M; Coulson, Sally; Yaxley, Gregory M; Grunsky, Eric C; Cox, Simon C

    2009-07-01

    Discrimination of material based on elemental composition was achieved within a compositional data (CoDa) analysis framework in a form appropriate for use in forensic science. The methods were carried out on example data from New Zealand nephrite. We have achieved good separation of the in situ outcrops of nephrite from within a well-defined area. The most significant achievement of working within the CoDa analysis framework is that the implications of the constraints on the data are acknowledged and dealt with, not ignored. The full composition was reduced based on collinearity of elements, principal components analysis (PCA) and scalings from a backwards linear discriminant analysis (LDA). Thus, a descriptive subcomposition was used for the final discrimination, using LDA, and proved to be more successful than using the full composition. The classification based on the LDA model showed a mean error rate of 2.9% when validated using a 10 repeat, three-fold cross-validation. The methods presented lend objectivity to the process of interpretation, rather than relying on subjective pattern matching type approaches.

  5. Human milk composition: nutrients and bioactive factors.

    Science.gov (United States)

    Ballard, Olivia; Morrow, Ardythe L

    2013-02-01

    This article provides an overview of the composition of human milk, its variation, and its clinical relevance. The composition of human milk is the biological norm for infant nutrition. Human milk also contains many hundreds to thousands of distinct bioactive molecules that protect against infection and inflammation and contribute to immune maturation, organ development, and healthy microbial colonization. Some of these molecules (eg, lactoferrin) are being investigated as novel therapeutic agents. Human milk changes in composition from colostrum to late lactation, within feeds, by gestational age, diurnally, and between mothers. Feeding infants with expressed human milk is increasing.

  6. The elemental composition of the Sun I. The intermediate mass elements Na to Ca

    CERN Document Server

    Scott, Pat; Asplund, Martin; Sauval, A Jacques; Lind, Karin; Takeda, Yoichi; Collet, Remo; Trampedach, Regner; Hayek, Wolfgang

    2014-01-01

    The composition of the Sun is an essential piece of reference data for astronomy, cosmology, astroparticle, space and geo-physics. This article, dealing with the intermediate-mass elements Na to Ca, is the first in a series describing the comprehensive re-determination of the solar composition. In this series we severely scrutinise all ingredients of the analysis across all elements, to obtain the most accurate, homogeneous and reliable results possible. We employ a highly realistic 3D hydrodynamic solar photospheric model, which has successfully passed an arsenal of observational diagnostics. To quantify systematic errors, we repeat the analysis with three 1D hydrostatic model atmospheres (MARCS, MISS and Holweger & M\\"uller 1974) and a horizontally and temporally-averaged version of the 3D model ($\\langle$3D$\\rangle$). We account for departures from LTE wherever possible. We have scoured the literature for the best transition probabilities, partition functions, hyperfine and other data, and stringently ...

  7. Elemental composition of birdsfoot trefoil. [Lotus corniculatus L

    Energy Technology Data Exchange (ETDEWEB)

    Russelle, M.P.; McGraw, R.L.; Grava, J.; Beuselinck, P.R.

    1985-01-01

    Developmental and environmental effects on mineral nutrient concentration in birdsfoot trefoil (Lotus corniculatus L.) are not well documented. In this study, elemental composition of two birdsfoot trefoil stands were determined from a late vegetative stage through reproductive growth. Norcen birdsfoot trefoil was established on a Glyndon silt loam (coarse-silty, frigid Aeric Calciaquolis)( in Roseau County, in 1980, and Norcen and Leo birdsfoot trefoil were seeded on a Waukegan silt loam (fine-silty over sandy or sandy-skeletal, mixed, mesic Typic Hapludolls) near Rosemount, in 1981. Shoot and root samples were taken at approximately biweekly intervals in the year following establishment. Shoots were separated into stems, leaves, umbels, and seed. Environment influenced the concentration of most elements. This environmental effect was generally consistent among plant parts for C, Mg, S, Na, and Mn; i.e., all parts had lower elemental concentrations at Rosemount than at Roseau. The relationship between environments for P, K, Zn, and Cu concentrations varied with different plant parts; i.e., some plant components had element concentrations higher at the southern than northern location, whereas other components had element concentrations that showed the converse. Although most elements were less concentrated with advancing developmental stage, environment modified the rate and extent of change in concentration of every element in at least one plant part. Interactions of environment with development stage were not as evident for shoots as for the separate shoot components. Whereas other reports have often emphasized the large differences in nutrient concentrations among legume species, this data suggest that nutrient concentration may be as strongly influenced by environment as by species.

  8. The features of finite-element modeling of a structural element of flexible woven composites

    Directory of Open Access Journals (Sweden)

    Dmitry A. Kozhanov

    2016-03-01

    Full Text Available The features of finite-element modeling of both an element itself and its behavior under uniaxial tension have been demonstrated with a structural element of flexible woven composites. The main components of the material, such as reinforcing fabric and material's matrix were examined in modeling. The reinforcing fabric is a plain weave. These yarns were taken as an elastic material. The matrix of the material was considered to be a soft polymer with the possible occurrence of irreversible elastic-plastic deformations. Moreover, the possible occurrence of damages in the structure of the material under high loads was taken into account in modeling. The fields of stresses and strains were built; the zones of the material's internal damages under uniaxial tension were demonstrated. The risk zones of weave were revealed.

  9. Finite-element impact response of debonded composite turbine blades

    Science.gov (United States)

    Dey, Sudip; Karmakar, Amit

    2014-02-01

    This paper investigates on the transient behavior of debonded composite pretwisted rotating shallow conical shells which could be idealized as turbine blades subjected to low velocity normal impact using finite-element method. Lagrange's equation of motion is used to derive the dynamic equilibrium equation and the moderate rotational speeds are considered neglecting the Coriolis effect. An eight-noded isoparametric plate bending element is employed in the finite element formulation incorporating rotary inertia and effects of transverse shear deformation based on Mindlin's theory. The modified Hertzian contact law which accounts for permanent indentation is utilized to compute the impact parameters. The time-dependent equations are solved by using Newmark's time integration scheme. Parametric studies are performed to investigate the effects of triggering parameters like angle of twist, rotational speed, laminate configuration and location of debonding considering low velocity normal impact at the center of eight-layered graphite-epoxy composite cantilevered conical shells with bending stiff ([0o2/{±} 30o]s), torsion stiff ([45°/-45°/-45°/45°]s) and cross-ply ([0°/90°/0°/90°]s) laminate configurations.

  10. Detection of transposable elements by their compositional bias

    Directory of Open Access Journals (Sweden)

    Anxolabéhère Dominique

    2004-07-01

    Full Text Available Abstract Background Transposable elements (TE are mobile genetic entities present in nearly all genomes. Previous work has shown that TEs tend to have a different nucleotide composition than the host genes, either considering codon usage bias or dinucleotide frequencies. We show here how these compositional differences can be used as a tool for detection and analysis of TE sequences. Results We compared the composition of TE sequences and host gene sequences using probabilistic models of nucleotide sequences. We used hidden Markov models (HMM, which take into account the base composition of the sequences (occurrences of words n nucleotides long, with n ranging here from 1 to 4 and the heterogeneity between coding and non-coding parts of sequences. We analyzed three sets of sequences containing class I TEs, class II TEs and genes respectively in three species: Drosophila melanogaster, Cænorhabditis elegans and Arabidopsis thaliana. Each of these sets had a distinct, homogeneous composition, enabling us to distinguish between the two classes of TE and the genes. However the particular base composition of the TEs differed in the three species studied. Conclusions This approach can be used to detect and annotate TEs in genomic sequences and complements the current homology-based TE detection methods. Furthermore, the HMM method is able to identify the parts of a sequence in which the nucleotide composition resembles that of a coding region of a TE. This is useful for the detailed annotation of TE sequences, which may contain an ancient, highly diverged coding region that is no longer fully functional.

  11. Human Capital Composition and Economic Growth

    Science.gov (United States)

    Tsai, Chun-Li; Hung, Ming-Cheng; Harriott, Kevin

    2010-01-01

    The objective of this paper is to analyze the effect of various compositions of human capital on economic growth. We construct alternative measures of human capital composition using five fields of study. In each instance, the measure represents the number of graduates in the respective field as a percentage of all graduates. The measures are as…

  12. Human Capital Composition and Economic Growth

    Science.gov (United States)

    Tsai, Chun-Li; Hung, Ming-Cheng; Harriott, Kevin

    2010-01-01

    The objective of this paper is to analyze the effect of various compositions of human capital on economic growth. We construct alternative measures of human capital composition using five fields of study. In each instance, the measure represents the number of graduates in the respective field as a percentage of all graduates. The measures are as…

  13. Trace Element Compositions of Pallasite Olivine Grains and Pallasite Origin

    Science.gov (United States)

    Mittlefehldt, David W.; Herrin, J. S.

    2010-01-01

    Pallasites are mixtures of metal with magnesian olivine. Most have similar metal compositions and olivine oxygen isotopic compositions; these are the main-group pallasites (PMG). The Eagle Station grouplet of pallasites (PES) have distinctive metal and olivine compositions and oxygen isotopic compositions. Pallasites are thought to have formed at the core-mantle boundary of their parent asteroids by mixing molten metal with solid olivine of either cumulatic or restitic origin. We have continued our investigation of pallasite olivines by doing in situ trace element analyses in order to further constrain their origin. We determined Al, P, Ca, Ga and first row transition element contents of olivine grains from suite of PMG and PES by LA-ICP-MS at JSC. Included in the PMG suite are some that have anomalous metal compositions (PMG-am) and atypically ferroan olivines (PMG-as). Our EMPA work has shown that there are unanticipated variations in olivine Fe/Mn, even within those PMG that have uni-form Fe/Mg. Manganese is homologous with Fe2+, and thus can be used the same way to investigate magmatic fractionation processes. It has an advantage for pallasite studies in that it is unaffected by redox exchange with the metal. PMG can be divided into three clusters on the basis of Mn/Mg; low, medium and high that can be thought of as less, typically and more fractionated in an igneous sense. The majority of PMG have medium Mn/Mg ratios. PMG-am occur in all three clusters; there does not seem to be any relationship between putative olivine igneous fractionation and metal composition. The PMG-as and one PMG-am make up the high Mn/Mg cluster; no PMG are in this cluster. The high Mn/Mg cluster ought to be the most fractionated (equivalent to the most Fe-rich in igneous suites), yet they have among the lowest contents of incompatible lithophile elements Al and Ti and the two PMG-as in this cluster also have low Ca and Sc contents. This is inconsistent with simple igneous

  14. COMPOSITE STRENGTHENING SOLUTIONS FOR REINFORCED CONCRETE LOAD BEARING ELEMENTS

    Directory of Open Access Journals (Sweden)

    Nicolae ȚĂRANU

    2015-11-01

    Full Text Available The results of a complex research and development program relating to the use of fiber reinforced polymeric composite strengthening solutions carried out at the Faculty of Civil Engineering and Building Services Iasi, are presented in this paper. The program has included the conceiving of the structural rehabilitation systems, the detailing and experimental testing of some solutions applied to reinforced concrete beams, slabs and columns (with circular and square cross-section. An efficient use of the component materials to improve the structural performance of the studied reinforced concrete element has been the main target of the research program. The main benefits resulted from the research program refer to the increase of the load capacities, the improvement of the structural response of all strengthened elements and a better control of the failure modes.

  15. Elemental composition of brazing alloys in metallic orthodontic brackets.

    Science.gov (United States)

    Zinelis, Spiros; Annousaki, Olga; Eliades, Theodore; Makou, Margarita

    2004-06-01

    The aim of this study was to assess the elemental composition of the brazing alloy of representative orthodontic brackets. The brackets examined were Gemini (3M, Unitec, Monrovia, Calif), MicroLoc (GAC, Bohemia, NY), OptiMESHxrt (Ormco, Glendora, Calif), and Ultratrim (Dentarum, Ispringen, Germany). Four metallic brackets for each brand were embedded in epoxy resin and after metallographic grinding and polishing were cleaned in a water ultrasonic bath. Scanning electron microscopy and energy-dispersive x-ray microanalysis (EDS) were used to assess the quantitative composition of the brazing alloy. Four EDS spectra were collected for each brazing alloy, and the mean value and standard deviation for the concentration of each element were calculated. The elemental composition of the brazing alloys was determined as follows (percent weight): Gemini: Ni = 83.98 +/- 1.02, Si = 6.46 +/- 0.37, Fe = 5.90 +/- 0.93, Cr = 3.52 +/- 0.34; MicroLoc: Ag = 42.82 +/- 0.18, Au = 32.14 +/- 0.65, Cu = 24.53 +/- 0.26, Mg = 1.12 +/- 0.33; OptiMESHxrt: Au = 67.79 +/- 0.97, Fe = 15.69 +/- 0.29, Ni = 13.01 +/- 0.93, Cr = 4.01 +/- 0.35; Ultratrim: Ag = 87.97 +/- 0.33, Cu = 10.51 +/- 0.45, Mg = 1.29 +/- 0.63, Zn = 1.13 +/- 0.24. The findings of this study showed that different brazing materials were used for the different brands, and thus different performances are expected during intraoral exposure; potential effects on the biological properties also are discussed.

  16. Elemental composition at different points of the rainwater harvesting system.

    Science.gov (United States)

    Morrow, A C; Dunstan, R H; Coombes, P J

    2010-09-15

    Entry of contaminants, such as metals and non-metals, into rainwater harvesting systems can occur directly from rainfall with contributions from collection surfaces, accumulated debris and leachate from storage systems, pipes and taps. Ten rainwater harvesting systems on the east coast of Australia were selected for sampling of roof runoff, storage systems and tap outlets to investigate the variations in rainwater composition as it moved throughout the system, and to identify potential points of contribution to elemental loads. A total of 26 elements were screened at each site. Iron was the only element which was present in significantly higher concentrations in roof runoff samples compared with tank tap samples (Prainwater. Increased loads of copper were observed in hot tap samples supplied by the rainwater harvesting system via copper piping and a storage hot water system (Pcollected from a polyvinyl chloride pipe sampling point that does not supply household uses, compared with corresponding roof runoff samples (Pcollected rainwater between different study sites and between different sampling points. Atmospheric deposition was not a major contributor to the rainwater contaminant load at the sites tested. Piping materials, however, were shown to contribute significantly to the total elemental load at some locations.

  17. New numerical analysis method in computational mechanics: composite element method

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new type of FEM, called CEM (composite element method), is proposed to solve the static and dynamic problems of engineering structures with high accuracy and efficiency. The core of this method is to define two sets of coordinate systems for DOF's description after discretizing the structure, i.e. the nodal coordinate system UFEM(ξ) for employing the conventional FEM, and the field coordinate system UCT(ξ) for utilizing classical theory. Then, coupling these two sets of functional expressions could obtain the composite displacement field U(ξ) of CEM. The computations of the stiffness and mass matrices can follow the conventional procedure of FEM. Since the CEM inherents some good properties of the conventional FEM and classical analytical method, it has the powerful versatility to various complex geometric shapes and excellent approximation. Many examples are presented to demonstrate the ability of CEM.

  18. New numerical analysis method in computational mechanics: composite element method

    Institute of Scientific and Technical Information of China (English)

    曾攀

    2000-01-01

    A new type of FEM, called CEM (composite element method), is proposed to solve the static and dynamic problems of engineering structures with high accuracy and efficiency. The core of this method is to define two sets of coordinate systems for DOF’ s description after discretizing the structure, i.e. the nodal coordinate system UFEM(ζ) for employing the conventional FEM, and the field coordinate system UCT(ζ) for utilizing classical theory. Then, coupling these two sets of functional expressions could obtain the composite displacement field U(ζ) of CEM. The computations of the stiffness and mass matrices can follow the conventional procedure of FEM. Since the CEM inherents some good properties of the conventional FEM and classical analytical method, it has the powerful versatility to various complex geometric shapes and excellent approximation. Many examples are presented to demonstrate the ability of CEM.

  19. Isotopic compositions of the elements 2013 (IUPAC Technical Report)

    Science.gov (United States)

    Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna; Loss, Robert D.; Walczyk, Thomas; Prohaska, Thomas

    2016-01-01

    The Commission on Isotopic Abundances and Atomic Weights (ciaaw.org) of the International Union of Pure and Applied Chemistry (iupac.org) has revised the Table of Isotopic Compositions of the Elements (TICE). The update involved a critical evaluation of the recent published literature. The new TICE 2013 includes evaluated data from the “best measurement” of the isotopic abundances in a single sample, along with a set of representative isotopic abundances and uncertainties that accommodate known variations in normal terrestrial materials.

  20. Estimation of elemental composition from proximate analysis of black liquor

    Energy Technology Data Exchange (ETDEWEB)

    Vakkilainen, E.K. [Andritz-Ahlstrom Corporation, Espoo (Finland)

    2000-07-01

    The black liquor properties will vary depending on the raw material used for pulping, the pulping conditions, the equipment used for pulping and the treatment of the liquor after the pulping. Accurate analysis of black liquor is needed to determine energy efficiency of o pulp mill, to calculate gas flows for environmental compliance reports and for production statistics. Black liquor composition and combustion properties can be estimated from known spread of data. Main source has been an internal company black liquor databank, which contains over 900 black liquor analysis. Regression equations for black liquor carbon, hydrogen, and inorganic element contents were derived. (orig.)

  1. Major element compositions of Luna 20 glass particles.

    Science.gov (United States)

    Glass, B. P.

    1973-01-01

    Major element analyses of nineteen Luna 20 glass particles indicate that most of the Luna 20 glasses have Al2O3 contents greater than 21 wt % and compositions similar to Apollo 16 and Luna 20 rocks and soils. Three of the glass particles have low Al2O3 (less than 13 wt %) and high FeO (greater than 18 wt %) contents and were probably derived from one of the adjacent maria. The low glass content of the Luna 20 soil indicates that it is relatively young or less mature than most mare soils that have been studied.

  2. K-type human endogenous retroviral elements in human melanoma

    Directory of Open Access Journals (Sweden)

    Rincon L

    2014-10-01

    Full Text Available Liliana Rincon,1 Michael P Sedrak,1 Huijian Sun,2 Gregorio Garza,3 Brent Kelly,4 Jianli Dong11Department of Pathology, 2School of Medicine, University of Texas Medical Branch, TX, USA; 3Ciencias de la Salud, Universidad de Monterrey, Nuevo León, Mexico; 4Department of Dermatology, University of Texas Medical Branch, TX, USAAbstract: Human endogenous retroviral elements (HERVs are thought to be germline-integrated genetic remnants of exogenous retroviral infections. HERVs comprise approximately 5%–8% of the human genome. Although all HERV genomes are highly defective, some, especially the K type (HERV-K, have the potential to be expressed and have biological activities. HERV-K expression has been detected in human melanomas. There are also reports on the regulation and potential activities of HERV-K in melanoma cells. Although a causal link between the activation of HERV-K and melanoma development has yet to be determined, existing data support the further research efforts in this area. In this review, we summarize the published studies on the expression, regulation, and activity of HERV-K in human melanoma.Keywords: HERV, HERV-K, melanoma development

  3. Long Fibre Composite Modelling Using Cohesive User's Element

    Science.gov (United States)

    Kozák, Vladislav; Chlup, Zdeněk

    2010-09-01

    The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.

  4. Geometrically Nonlinear Finite Element Analysis of a Composite Space Reflector

    Science.gov (United States)

    Lee, Kee-Joo; Leet, Sung W.; Clark, Greg; Broduer, Steve (Technical Monitor)

    2001-01-01

    Lightweight aerospace structures, such as low areal density composite space reflectors, are highly flexible and may undergo large deflection under applied loading, especially during the launch phase. Accordingly, geometrically nonlinear analysis that takes into account the effect of finite rotation may be needed to determine the deformed shape for a clearance check and the stress and strain state to ensure structural integrity. In this study, deformation of the space reflector is determined under static conditions using a geometrically nonlinear solid shell finite element model. For the solid shell element formulation, the kinematics of deformation is described by six variables that are purely vector components. Because rotational angles are not used, this approach is free of the limitations of small angle increments. This also allows easy connections between substructures and large load increments with respect to the conventional shell formulation using rotational parameters. Geometrically nonlinear analyses were carried out for three cases of static point loads applied at selected points. A chart shows results for a case when the load is applied at the center point of the reflector dish. The computed results capture the nonlinear behavior of the composite reflector as the applied load increases. Also, they are in good agreement with the data obtained by experiments.

  5. BRCA1 Exon 11, a CERES (Composite Regulatory Element of Splicing Element Involved in Splice Regulation

    Directory of Open Access Journals (Sweden)

    Claudia Tammaro

    2014-07-01

    Full Text Available Unclassified variants (UV of BRCA1 can affect normal pre-mRNA splicing. Here, we investigate the UV c.693G>A, a “silent” change in BRCA1 exon 11, which we have found induces aberrant splicing in patient carriers and in vitro. Using a minigene assay, we show that the UV c.693G>A has a strong effect on the splicing isoform ratio of BRCA1. Systematic site-directed mutagenesis of the area surrounding the nucleotide position c.693G>A induced variable changes in the level of exon 11 inclusion/exclusion in the mRNA, pointing to the presence of a complex regulatory element with overlapping enhancer and silencer functions. Accordingly, protein binding analysis in the region detected several splicing regulatory factors involved, including SRSF1, SRSF6 and SRSF9, suggesting that this sequence represents a composite regulatory element of splicing (CERES.

  6. Human Exploration Telerobotics (HET2): Astrobee Element

    Data.gov (United States)

    National Aeronautics and Space Administration — The HET2 Astrobee Element will focus on developing a new free-flying robot suitable for performing IVA work on the International Space Station (ISS). The new robot...

  7. Neural network applied to elemental archaeological Marajoara ceramic compositions

    Energy Technology Data Exchange (ETDEWEB)

    Toyota, Rosimeiri G.; Munita, Casimiro S., E-mail: rosimeiritoy@yahoo.com.b, E-mail: camunita@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Boscarioli, Clodis, E-mail: boscarioli@gmail.co [Universidade Estadual do Oeste do Parana, Cascavel, PR (Brazil). Centro de Ciencias Exatas e Tecnologicas. Colegiado de Informatica; Hernandez, Emilio D.M., E-mail: boscarioli@gmail.co [Universidade de Sao Paulo (USP), SP (Brazil). Escola Politecnica; Neves, Eduardo G.; Demartini, Celia C., E-mail: eduardo@pq.cnpq.b [Museu de Arqueologia e Etnologia (MAE/USP), Sao Paulo, SP (Brazil)

    2009-07-01

    In the last decades several analytical techniques have been used in archaeological ceramics studies. However, instrumental neutron activation analysis, INAA, employing gamma-ray spectrometry seems to be the most suitable technique because it is a simple analytical method in its purely instrumental form. The purpose of this work was to determine the concentration of Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb, and Zn in 160 original marajoara ceramic fragments by INAA. Marajoara ceramics culture was sophisticated and well developed. This culture reached its peak during the V and XIV centuries in Marajo Island located on the Amazon River delta area in Brazil. The purpose of the quantitative data was to identify compositionally homogeneous groups within the database. Having this in mind, the data set was first converted to base-10 logarithms to compensate for the differences in magnitude between major elements and trace elements, and also to yield a closer to normal distribution for several trace elements. After that, the data were analyzed using the Mahalanobis distance and using the lambda Wilks as critical value to identify the outliers. The similarities among the samples were studied by means of cluster analysis, principal components analysis and discriminant analysis. Additional confirmation of these groups was made by using elemental concentration bivariate plots. The results showed that there were two very well defined groups in the data set. In addition, the database was studied using artificial neural network with unsupervised learning strategy known as self-organizing maps to classify the marajoara ceramics. The experiments carried out showed that self-organizing maps artificial neural network is capable of discriminating ceramic fragments like multivariate statistical methods, and, again the results showed that the database was formed by two groups. (author)

  8. Comparative studies of elemental composition in leaves and flowers of Catharanthus roseus growing in Bangladesh

    Institute of Scientific and Technical Information of China (English)

    Shahin Aziz; Koushik Saha; Nasim Sultana; Husna Parvin Nur; Md.Aminul Ahsan; Shamim Ahmed; Md.Kamal Hossain

    2016-01-01

    Objective:To investigate the elemental composition of the leaves and flowers of Catharanthus roseus(C.roseus) due to the plant’s wide application in the indigenous medicinal system and its chemical constituents’ importance.Methods:The atomic absorption spectrophotometer was used for quantitative analysis of various elements.Results:Total 13 important elements were analyzed in leaves and flowers of C.roseus.Results indicated the presence of Na,K,Ca,Mg,Cr,Fe,Zn,Al,Cu,Ni,Pb,Cd and Mn in both leaves and flowers.The most important finding of the work was that,leaves of C.roseus showed high concentration of all elements except K and Zn while flowers of C.roseus showed higher concentration of K and Zn.Conclusions:The elemental composition in both leaves and flowers of C.roseus were found to be different.Therefore,different parts of this medicinal plant are enriched in some micro and macro nutrients like Fe,Ca,Na,K,Zn,which are very important for biological metabolic system as well as human health.

  9. Comparative studies of elemental composition in leaves and flowers of Catharanthus roseus growing in Bangladesh

    Institute of Scientific and Technical Information of China (English)

    Shahin Aziz; Koushik Saha; Nasim Sultana; Husna Parvin Nur; Md Aminul Ahsan; Shamim Ahmed; Md Kamal Hossain

    2016-01-01

    Objective: To investigate the elemental composition of the leaves and flowers of Catharanthus roseus (C. roseus) due to the plant's wide application in the indigenous medicinal system and its chemical constituents' importance. Methods: The atomic absorption spectrophotometer was used for quantitative analysis of various elements. Results: Total 13 important elements were analyzed in leaves and flowers of C. roseus. Results indicated the presence of Na, K, Ca, Mg, Cr, Fe, Zn, Al, Cu, Ni, Pb, Cd and Mn in both leaves and flowers. The most important finding of the work was that, leaves of C. roseus showed high concentration of all elements except K and Zn while flowers of C. roseus showed higher concentration of K and Zn. Conclusions: The elemental composition in both leaves and flowers of C. roseus were found to be different. Therefore, different parts of this medicinal plant are enriched in some micro and macro nutrients like Fe, Ca, Na, K, Zn, which are very important for biological metabolic system as well as human health.

  10. Determination of element levels in human serum: Total reflection X-ray fluorescence applications

    Science.gov (United States)

    Majewska, U.; Łyżwa, P.; Łyżwa, K.; Banaś, D.; Kubala-Kukuś, A.; Wudarczyk-Moćko, J.; Stabrawa, I.; Braziewicz, J.; Pajek, M.; Antczak, G.; Borkowska, B.; Góźdź, S.

    2016-08-01

    Deficiency or excess of elements could disrupt proper functioning of the human body and could lead to several disorders. Determination of their concentrations in different biological human fluids and tissues should become a routine practice in medical treatment. Therefore the knowledge about appropriate element concentrations in human organism is required. The purpose of this study was to determine the concentration of several elements (P, S, Cl, K, Ca, Cr, Fe, Cu, Zn, Se, Br, Rb, Pb) in human serum and to define the reference values of element concentration. Samples of serum were obtained from 105 normal presumably healthy volunteers (66 women aged between 15 and 78 years old; 39 men aged between 15 and 77 years old). Analysis has been done for the whole studied population and for subgroups by sex and age. It is probably first so a wide study of elemental composition of serum performed in the case of Świętokrzyskie region. Total reflection X-ray fluorescence (TXRF) method was used to perform the elemental analysis. Spectrometer S2 Picofox (Bruker AXS Microanalysis GmbH) was used to identify and measure elemental composition of serum samples. Finally, 1st and 3rd quartiles were accepted as minimum and maximum values of concentration reference range.

  11. Composite Stellar Populations and Element by Element Abundances in the Milky Way Bulge and Elliptical Galaxies

    CERN Document Server

    Tang, Baitian; Davis, A Bianca

    2014-01-01

    This paper explores the integrated-light characteristics of the Milky Way (MW) bulge and to what extent they match those of elliptical galaxies in the local universe. We model composite stellar populations with realistic abundance distribution functions (ADFs), tracking the trends of individual elements as a function of overall heavy element abundance as actually observed in MW bulge stars. The resultant predictions for absorption feature strengths from the MW bulge mimic elliptical galaxies better than solar neighborhood stars do, but the MW bulge does not match elliptical galaxies, either. Comparing bulge versus elliptical galaxies, Fe, Ti, and Mg trend about the same for both but C, Na, and Ca seem irreconcilably different. Exploring the behavior of abundance compositeness leads to the concepts of "red lean" where a narrower ADF appears more metal rich than a wide one, and "red spread" where the spectral difference between wide and narrow ADFs increases as the ADF peak is moved to more metal-rich values. T...

  12. The elemental composition of the Sun. I. The intermediate mass elements Na to Ca

    Science.gov (United States)

    Scott, Pat; Grevesse, Nicolas; Asplund, Martin; Sauval, A. Jacques; Lind, Karin; Takeda, Yoichi; Collet, Remo; Trampedach, Regner; Hayek, Wolfgang

    2015-01-01

    The chemical composition of the Sun is an essential piece of reference data for astronomy, cosmology, astroparticle, space and geo-physics: elemental abundances of essentially all astronomical objects are referenced to the solar composition, and basically every process involving the Sun depends on its composition. This article, dealing with the intermediate-mass elements Na to Ca, is the first in a series describing the comprehensive re-determination of the solar composition. In this series we severely scrutinise all ingredients of the analysis across all elements, to obtain the most accurate, homogeneous and reliable results possible. We employ a highly realistic 3D hydrodynamic model of the solar photosphere, which has successfully passed an arsenal of observational diagnostics. For comparison, and to quantify remaining systematic errors, we repeat the analysis using three different 1D hydrostatic model atmospheres (marcs, miss and Holweger & Müller 1974, Sol. Phys., 39, 19) and a horizontally and temporally-averaged version of the 3D model (⟨ 3D ⟩). We account for departures from local thermodynamic equilibrium (LTE) wherever possible. We have scoured the literature for the best possible input data, carefully assessing transition probabilities, hyperfine splitting, partition functions and other data for inclusion in the analysis. We have put the lines we use through a very stringent quality check in terms of their observed profiles and atomic data, and discarded all that we suspect to be blended. Our final recommended 3D+NLTE abundances are: log ɛNa = 6.21 ± 0.04, log ɛMg = 7.59 ± 0.04, log ɛAl = 6.43 ± 0.04, log ɛSi = 7.51 ± 0.03, log ɛP = 5.41 ± 0.03, log ɛS = 7.13 ± 0.03, log ɛK = 5.04 ± 0.05 and log ɛCa = 6.32 ± 0.03. The uncertainties include both statistical and systematic errors. Our results are systematically smaller than most previous ones with the 1D semi-empirical Holweger & Müller model, whereas the ⟨ 3D ⟩ model returns

  13. Element free Galerkin formulation of composite beam with longitudinal slip

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, Dzulkarnain; Mokhtaram, Mokhtazul Haizad [Department of Civil Engineering, Universiti Selangor, Bestari Jaya, Selangor (Malaysia); Badli, Mohd Iqbal; Yassin, Airil Y. Mohd [Faculty of Civil Engineering, Universiti Teknologi Malaysia, Skudai, Johor (Malaysia)

    2015-05-15

    Behaviour between two materials in composite beam is assumed partially interact when longitudinal slip at its interfacial surfaces is considered. Commonly analysed by the mesh-based formulation, this study used meshless formulation known as Element Free Galerkin (EFG) method in the beam partial interaction analysis, numerically. As meshless formulation implies that the problem domain is discretised only by nodes, the EFG method is based on Moving Least Square (MLS) approach for shape functions formulation with its weak form is developed using variational method. The essential boundary conditions are enforced by Langrange multipliers. The proposed EFG formulation gives comparable results, after been verified by analytical solution, thus signify its application in partial interaction problems. Based on numerical test results, the Cubic Spline and Quartic Spline weight functions yield better accuracy for the EFG formulation, compares to other proposed weight functions.

  14. Elemental distribution in human femoral head

    Energy Technology Data Exchange (ETDEWEB)

    Santos, C., E-mail: catia.santos@itn.pt [Dep. Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Física Nuclear da Universidade de Lisboa, 1649-003 Lisboa (Portugal); Campus Tecnológico e Nuclear, IST/CTN, Universidade Técnica de Lisboa E.N. 10, 2686-953 Sacavém (Portugal); Fonseca, M. [Dep. Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Física Nuclear da Universidade de Lisboa, 1649-003 Lisboa (Portugal); Universidade Europeia|Laureate International Universities, 1500-210 Lisboa (Portugal); Corregidor, V. [Campus Tecnológico e Nuclear, IST/CTN, Universidade Técnica de Lisboa E.N. 10, 2686-953 Sacavém (Portugal); Silva, H. [Dep. Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Física Nuclear da Universidade de Lisboa, 1649-003 Lisboa (Portugal); Campus Tecnológico e Nuclear, IST/CTN, Universidade Técnica de Lisboa E.N. 10, 2686-953 Sacavém (Portugal); Luís, H.; Jesus, A.P. [Dep. Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Centro de Física Nuclear da Universidade de Lisboa, 1649-003 Lisboa (Portugal); and others

    2014-07-15

    Osteoporosis is the most common bone disease with severe symptoms and harmful effects on the patient quality of life. Because abnormal distribution and concentration of the major and trace elements may help to characterize the disease, ion beam analysis is applied to the study of bone samples. Proton Induced X-ray Emission and Elastic Backscattering Spectrometry are applied for qualitative and quantitative analysis of an osteoporotic bone sample, for the determination of the Ca/P ratio and analysis of the distribution of major and trace elements. The analysis was made both in trabecular and cortical bone and the results are in agreement with the information found in literature.

  15. Elemental distribution in human femoral head

    Science.gov (United States)

    Santos, C.; Fonseca, M.; Corregidor, V.; Silva, H.; Luís, H.; Jesus, A. P.; Branco, J.; Alves, L. C.

    2014-07-01

    Osteoporosis is the most common bone disease with severe symptoms and harmful effects on the patient quality of life. Because abnormal distribution and concentration of the major and trace elements may help to characterize the disease, ion beam analysis is applied to the study of bone samples. Proton Induced X-ray Emission and Elastic Backscattering Spectrometry are applied for qualitative and quantitative analysis of an osteoporotic bone sample, for the determination of the Ca/P ratio and analysis of the distribution of major and trace elements. The analysis was made both in trabecular and cortical bone and the results are in agreement with the information found in literature.

  16. Stepwise evolution of two giant composite LTR-retrotransposon-like elements DA and Xiao

    Directory of Open Access Journals (Sweden)

    Li Xuanyang

    2009-06-01

    Full Text Available Abstract Background We recently discovered two composite long terminal repeat (LTR-retrotransposon-like elements which we named DA (~300 kb and Xiao (~30 kb, meaning big and small in Chinese respectively. Xiao and DA (three types of DA identified were found to have been derived from several donor sites and have spread to 30 loci in the human genome, totaling to 5 Mb. Our bioinformatics analyses with the released human, chimp, rhesus macaque, orangutan, and marmoset genomic sequences indicate that DA and Xiao emerged ~25 million years (Myr ago. Results To better understand the evolution of these two complex elements, we investigated various internal junctions of DA and Xiao as well as orthologous genomic sites of the 30 DA/Xiao loci in non-human primates including great apes, lesser apes, Old World monkeys, New World monkeys, and a prosimian. We found that Xiao and type I DA first emerged in the genome between 25 and 18 Myr ago, whereas type II and Type III DAs emerged between 14 and 7 Myr ago. Xiao and DA were most active in great apes, with their amplification peaking during 25-14 and 14-7 Myr ago, respectively. Neither DA nor Xiao seem to have been active in the human and chimp genomes during last 6 Myr. Conclusion The study has led to a more accurate age determination of the DA and Xiao elements than our previous bioinformatics analyses, and indicates that the amplification activity of the elements coincided with that of group I HERV-Es during evolution. It has also illustrated an evolutionary path with stepwise structural changes for the elements during past 25 Myr, and in doing so has shed more light on these two intriguing and complex elements that have reshaped our genome.

  17. Vibration analysis of composite pipes using the finite element method with B-spline wavelets

    Energy Technology Data Exchange (ETDEWEB)

    Oke, Wasiu A.; Khulief, Yehia A. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

    2016-02-15

    A finite element formulation using the B-spline wavelets on the interval is developed for modeling the free vibrations of composite pipes. The composite FRP pipe element is treated as a beam element. The finite pipe element is constructed in the wavelet space and then transformed to the physical space. Detailed expressions of the mass and stiffness matrices are derived for the composite pipe using the Bspline scaling and wavelet functions. Both Euler-Bernoulli and Timoshenko beam theories are considered. The generalized eigenvalue problem is formulated and solved to obtain the modal characteristics of the composite pipe. The developed wavelet-based finite element discretization scheme utilizes significantly less elements compared to the conventional finite element method for modeling composite pipes. Numerical solutions are obtained to demonstrate the accuracy of the developed element, which is verified by comparisons with some available results in the literature.

  18. A novel tetrahedal element for static and dynamic analysis of laminated composites

    Energy Technology Data Exchange (ETDEWEB)

    Jones, I A; Ruijter, W; Long, A C, E-mail: arthur.jones@nottingham.ac.u, E-mail: woutruijter@gmail.co, E-mail: andrew.long@nottingham.ac.u [Division of Materials, Mechanics and Structures, Faculty of Engineering, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2009-08-01

    This paper presents a novel approach to formulating finite elements for modelling laminated composites. Most FE systems provide laminated composite elements based upon layered shell elements and some provide layered brick elements, but these require a hexahedral mesh which is difficult to generate for arbitrary geometries. This paper describes a tetrahedral element based on the concept of an equivalent graded material whose properties vary smoothly (rather than stepwise) and whose global behaviour replicates that of the laminate. This allows the possibility of automatically-generated models involving laminated composite behaviour. The element requires a non-standard integration system, and is presented for the cases of elastic, thermoelastic and dynamic behaviour.

  19. Lipid composition of human meibum

    Directory of Open Access Journals (Sweden)

    R. Schnetler

    2013-12-01

    Full Text Available The structure and function of meibomian gland lipids in the tear film are highly complex. Evidence shows that the precorneal tear film consists of discrete layers: the inner mucin layer, the middle aqueous layer and the outer lipid layer. In this review we focus on the outer, biphasic lipid layer of the tear film which consists of a ‘thick’ outer, non-polar layer  and a ‘thin’ inner, polar layer. We discuss the main composition of the polar and non-polar lipids within meibum (wax esters, cholesteryl esters, mono-, di- and tri-acylglycerols, ceramides, phospholipids  et cetera. We address the composition of meibomian lipids in subjects suffering from various ocular diseases in comparison with the composition in healthy individuals. Further analysis is needed to determine whether a correlation exists between the etiology of various ocular diseases and the fluctuation on the lipids as well as to establish whether or not tear lipid analysis can be used as a diagnostic tool.

  20. [The elemental composition of teeth hard tissues depending on the state of the environment].

    Science.gov (United States)

    Suladze, N; Shishniashvili, T; Margvelashvili, V; Kobakhidze, K

    2014-01-01

    At present, great attention is paid to the origin of man-made micro elemental anomalies. To monitor the state of the environment and its effects on the human body, of great importance is the determination of the amount and distribution of various chemical elements in the dentin and enamel of the teeth. To determine the essential (Ca, Zn, Mn, Ni), conditionally essential (Rb, Ni, Sr) and toxic (Pb, Hg) trace elements in the mineralized tissues of the teeth and to identify the relationship between the elemental composition of the tooth structure and the state of the general and dental health depending on the state of the environment, we have examined 29 children aged 3-4 years who have carried out analysis of hard tissue of teeth (teeth used for remote medical reasons) for the maintenance of nine chemical elements. Children living in a relatively environmentally favorable conditions essential value and conditionally essential elements in the mineralized tissues of the teeth were within normal limits, and toxic elements slightly increased limits that differ from those of children living in environmentally disadvantaged areas. In particular, these essential elements were significantly reduced (except for zinc), as indicators of toxic elements - mercury and lead, increased by 12.5% and 44.5%, respectively, which is clearly reflected on the state of dental health because noted decompensated form of tooth decay. Thus, deviations in a state of general and dental health of children associated with an imbalance of macro-and microelements in the mineralized tissues of the teeth.

  1. Total leaf crude protein, amino acid composition and elemental content in the USDA-ARS bamboo germplasm collection

    Science.gov (United States)

    Bamboo shoots and leaves are valuable food sources for both humans and livestock. The USDA-ARS National Plant Germplasm System (NPGS) collections hold 93 bamboo species in 20 genera. Total leaf protein, amino acid composition and elemental content for these important genetic resources had never bee...

  2. Human Robotic Systems (HRS): Robonaut 2 Technologies Element

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the Robonaut 2 (R2) Technology Project Element within Human Robotic Systems (HRS) is to developed advanced technologies for infusion into the Robonaut 2...

  3. Viscoelastic finite-element analysis of human skull - dura mater ...

    African Journals Online (AJOL)

    SERVER

    2008-03-18

    Mar 18, 2008 ... In the work, the dynamic characteristics of the human skull-dura mater ... Ansys' finite element processor, a simplified three-dimensional finite element ... brain, cerebrospinal fluid (CSF), and the brain's blood ... ICP is often not preventable. .... The creep of linear viscoelastic solid can be simulated by the.

  4. Morphology and Elemental Composition of Recent and Fossil Cyanobacteria

    Science.gov (United States)

    SaintAmand, Ann; Hoover, Richard B.; Jerman, Gregory; Rozanov, Alexei Yu.

    2005-01-01

    Cyanobacteria (cyanophyta, cyanoprokaryota, and blue-green algae) are an ancient, diverse and abundant group of photosynthetic oxygenic microorganisms. Together with other bacteria and archaea, the cyanobacteria have been the dominant life forms on Earth for over 3.5 billion years. Cyanobacteria occur in some of our planets most extreme environments - hot springs and geysers, hypersaline and alkaline lakes, hot and cold deserts, and the polar ice caps. They occur in a wide variety of morphologies. Unlike archaea and other bacteria, which are typically classified in pure culture by their physiological, biochemical and phylogenetic properties, the cyanobacteria have historically been classified based upon their size and morphological characteristics. These include the presence or absence of heterocysts, sheath, uniseriate or multiseriate trichomes, true or false branching, arrangement of thylakoids, reproduction by akinetes, binary fission, hormogonia, fragmentation, presence/absence of motility etc. Their antiquity, distribution, structural and chemical differentiation, diversity, morphological complexity and large size compared to most other bacteria, makes the cyanobacteria ideal candidates for morphological biomarkers in returned Astromaterials. We have obtained optical (nomarski and phase contrast)/fluorescent (blue and green excitation) microscopy images using an Olympus BX60 compound microscope and Field Emission Scanning Electron Microscopy images and EDAX elemental compositions of living and fossil cyanobacteria. The S-4000 Hitachi Field Emission Scanning Electron Microscope (FESEM) has been used to investigate microfossils in freshly fractured interior surfaces of terrestrial rocks and the cells, hormogonia, sheaths and trichomes of recent filamentous cyanobacteria. We present Fluorescent and FESEM Secondary and Backscattered Electron images and associated EDAX elemental analyses of recent and fossil cyanobacteria, concentrating on representatives of the

  5. Morphology and elemental composition of recent and fossil cyanobacteria

    Science.gov (United States)

    St. Amand, Ann; Hoover, Richard B.; Jerman, Gregory A.; Coston, James; Rozanov, Alexei Y.

    2005-09-01

    Cyanobacteria (cyanophyta, cyanoprokaryota, and blue-green algae) are an ancient, diverse and abundant group of photosynthetic oxygenic microorganisms. Together with other bacteria and archaea, the cyanobacteria have been the dominant life forms on Earth for over 3.5 billion years. Cyanobacteria occur in some of our planets most extreme environments - hot springs and geysers, hypersaline and alkaline lakes, hot and cold deserts, and the polar ice caps. They occur in a wide variety of morphologies. Unlike archaea and other bacteria, which are typically classified in pure culture by their physiological, biochemical and phylogenetic properties, the cyanobacteria have historically been classified based upon their size and morphological characteristics. These include the presence or absence of heterocysts, sheath, uniseriate or multiseriate trichomes, true or false branching, arrangement of thylakoids, reproduction by akinetes, binary fission, hormogonia, fragmentation, presence/absence of motility etc. Their antiquity, distribution, structural and chemical differentiation, diversity, morphological complexity and large size compared to most other bacteria, makes the cyanobacteria ideal candidates for morphological biomarkers in returned Astromaterials. We have obtained optical (nomarski and phase contrast)/fluorescent (blue and green excitation) microscopy images using an Olympus BX60 compound microscope and Field Emission Scanning Electron Microscopy images and EDAX elemental compositions of living and fossil cyanobacteria. The S-4000 Hitachi Field Emission Scanning Electron Microscope (FESEM) has been used to investigate microfossils in freshly fractured interior surfaces of terrestrial rocks and the cells, hormogonia, sheaths and trichomes of recent filamentous cyanobacteria. We present Fluorescent and FESEM Secondary and Backscattered Electron images and associated EDAX elemental analyses of recent and fossil cyanobacteria, concentrating on representatives of the

  6. Elemental composition of extant microbialites: mineral and microbial carbon

    Science.gov (United States)

    Valdespino-Castillo, P. M.; Falcón, L. I.; Holman, H. Y. N.; Merino-Ibarra, M.; García-Guzmán, M.; López-Gómez, L. M. D. R.; Martínez, J.; Alcantara-Hernandez, R. J.; Beltran, Y.; Centeno, C.; Cerqueda-Garcia, D.; Pi-Puig, T.; Castillo, F. S.

    2015-12-01

    Microbialites are the modern analogues of ancient microbial consortia. Their existence extends from the Archaean (~3500 mya) until present and their lithified structure evidences the capacity of microbial communities to mediate mineral precipitation. Living microbialites are a useful study model to test the mechanisms involved in carbonates and other minerals precipitation. Here, we studied the chemical composition, the biomass and the microbial structure of extant microbialites. All of these were found in Mexico, in water systems of different and characteristic ionic firms. An elemental analysis (C:N) of microbial biomass was performed and total P was determined. To explore the chemical composition of microbialites as a whole, X-ray diffraction analyses were performed over dry microbialites. While overall inorganic carbon content (carbonates) represented >70% of the living layer, a protocol of inorganic carbon elimination was performed for each sample resulting in organic matter contents between 8 and 16% among microbialites. Stoichiometric ratios of C:N:P in microbialite biomass were different among samples, and the possibility of P limitation was suggested mainly for karstic microbialites, N limitation was suggested for all samples and, more intensively, for soda system microbialites. A differential capacity for biomass allocation among microbialites was observed. Microbialites showed, along the biogeographic gradient, a diverse arrangement of microbial assemblages within the mineral matrix. While environmental factors such as pH and nitrate concentration were the factors that defined the general structure and diversity of these assemblages, we intend to test if the abundance of major ions and trace metals are also defining microbialite characteristics (such as microbial structure and biomass). This work contributes to define a baseline of the chemical nature of extant microbial consortia actively participating in mineral precipitation processes.

  7. The Human Element in the Virtual Library.

    Science.gov (United States)

    Saunders, Laverna M.

    1999-01-01

    Introduces the concept of the virtual library and explores how the increasing reliance on computers and digital information has affected library users and staff. Discusses users' expectations, democratization of access, human issues, organizational change, technostress, ergonomics, assessment, and strategies for success and survival. Contains 35…

  8. Investigation of the Structure and Element Composition of C-Phycocyanin Extracted from the Microalgae Spirulina platensis

    CERN Document Server

    Mosulishvili, L M; Kirkesali, E I; Khizanishvili, A I; Frontasyeva, M V; Pavlov, S S; Gundorina, S F

    2002-01-01

    The structure and element composition of C-phycocyanin (C-PC) extracted from the blue-green alga Spirulina platensis were studied. The behavior of structural subunits forming phycobilisomes in the purification process was studied by capillary electrophoresis. Their proportion in high-purity C-PC was determined. The element composition of C-PC of different purity was studied by means of epithermal neutron activation analysis, and metals which may form macromolecular complexes with C-PC were determined (Zn, Cr, Ni, Co, As, Sr, Mo, Ag, Hg). It was shown that contents of toxic metals did not exceed accepted permissible levels for the human organism.

  9. Finite element simulations of thin-film composite BAW resonators.

    Science.gov (United States)

    Makkonen, T; Holappa, A; Ellä, J; Salomaa, M M

    2001-09-01

    A finite element method (FEM) formulation is presented for the numerical solution of the electroelastic equations that govern the linear forced vibrations of piezoelectric media. A harmonic time dependence is assumed. Both of the approaches, that of solving the field problem (harmonic analysis) and that of solving the corresponding eigenvalue problem (modal analysis), are described. A FEM software package has been created from scratch. Important aspects central to the efficient implementation of FEM are explained, such as memory management and solving the generalized piezoelectric eigenvalue problem. Algorithms for reducing the required computer memory through optimization of the matrix profile, as well as Lanczos algorithm for the solution of the eigenvalue problem are linked into the software from external numerical libraries. Our FEM software is applied to detailed numerical modeling of thin-film bulk acoustic wave (BAW) composite resonators. Comparison of results from 2D and full 39 simulations of a resonator are presented. In particular, 3D simulations are used to investigate the effect of the top electrode shape on the resonator electrical response. The validity of the modeling technique is demonstrated by comparing the simulated and measured displacement profiles at several frequencies. The results show that useful information on the performance of the thin-film resonators can be obtained even with relatively coarse meshes and, consequently, moderate computational resources.

  10. Soviet space flight: the human element.

    Science.gov (United States)

    Garshnek, V

    1989-07-01

    Building on past experience and knowledge, the Soviet manned space flight effort has become broad, comprehensive, and forward-looking. Their long-running space station program has provided the capabilities to investigate long-term effects of microgravity on human physiology and behavior, and test various countermeasures against microgravity-induced physiological deconditioning. Since the beginning of Soviet manned space flight, the biomedical training and preparation of cosmonauts has evolved from a process that increased human tolerance to space flight factors, to a system of interrelated measures to prepare cosmonauts physically and psychologically to live and work in space. Currently, the Soviet Union is constructing a multimodular space station, the Mir. With the emergence of dedicated laboratory modules, the Soviets have begun the transition from small-scale experimental research to large-scale production activities and specialized scientific work in space. In the future, additional laboratory modules will be added, including one dedicated to biomedical research, called the "Medilab." The longest manned space flight to date (326 d) has been completed by the Soviets. The biomedical effects of previous long-duration flights, and perhaps those of still greater length, may contribute important insight into the possibility of extended missions beyond Earth, such as a voyage to Mars.

  11. Characteristics of transposable element exonization within human and mouse.

    Directory of Open Access Journals (Sweden)

    Noa Sela

    Full Text Available Insertion of transposed elements within mammalian genes is thought to be an important contributor to mammalian evolution and speciation. Insertion of transposed elements into introns can lead to their activation as alternatively spliced cassette exons, an event called exonization. Elucidation of the evolutionary constraints that have shaped fixation of transposed elements within human and mouse protein coding genes and subsequent exonization is important for understanding of how the exonization process has affected transcriptome and proteome complexities. Here we show that exonization of transposed elements is biased towards the beginning of the coding sequence in both human and mouse genes. Analysis of single nucleotide polymorphisms (SNPs revealed that exonization of transposed elements can be population-specific, implying that exonizations may enhance divergence and lead to speciation. SNP density analysis revealed differences between Alu and other transposed elements. Finally, we identified cases of primate-specific Alu elements that depend on RNA editing for their exonization. These results shed light on TE fixation and the exonization process within human and mouse genes.

  12. Element composition of biota, water and sediment in the Forsmark area, Baltic Sea. Concentrations, bioconcentration factors and partitioning coefficients (K{sub d}) of 48 elements

    Energy Technology Data Exchange (ETDEWEB)

    Kumblad, Linda; Bradshaw, Clare (Dept. of Systems Ecology, Stockholm Univ. (Sweden))

    2008-08-15

    In this study the elemental composition of biota, water and sediment from a shallow bay in the Forsmark region have been determined. The report presents data for 48 different elements (Al, As, Ba, Br, C, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Er, Eu, F, Fe, Gd, Hg, Ho, I, K, Li, Lu, Mg, Mn, N, Na, Nd, Ni, P, Pb, Pr, Ra, Rb, S, Se, Si, Sm, Tb, Th, Ti, Tm, V, Yb, Zn, Zr) in all major functional groups of the coastal ecosystem (phytoplankton, zooplankton, benthic microalgae, macroalgae, macrophytes, benthic herbivores, benthic filter feeders, benthic detrivores, planktivorous fish, benthic omnivorous fish, carnivorous fish, dissolved and particulate matter in the water and the sediment) during spring 2005. The overall aim of the study is to contribute to a better understanding of ecological properties and processes that govern uptake and transfer of trace elements, heavy-metals, radionuclides and other non-essential elements/contaminants in coastal environments of the Baltic Sea. In addition, the data was collected to provide site-specific Bioconcentration Factors (BCF), Biomagnification Factors (BMF), partitioning coefficients (K{sub d}) and element ratios (relative to carbon) for use in ongoing SKB safety assessments. All these values, as well as the element concentration data from which they are derived, are presented here. As such, this is mainly a data report, although initial interpretations of the data also are presented and discussed. Reported data include element concentrations, CNP-stoichiometry, and multivariate data analysis. Elemental concentrations varied greatly between organisms and environmental components, depending on the function of the elements, and the habitat, ecosystem function, trophic level and morphology (taxonomy) of the organisms. The results show for instance that food intake and metabolism strongly influence the elemental composition of organisms. The three macrophytes had quite similar elemental composition (despite their taxonomic

  13. Elemental compositions of comet 81P/Wild 2 samples collected by Stardust.

    Science.gov (United States)

    Flynn, George J; Bleuet, Pierre; Borg, Janet; Bradley, John P; Brenker, Frank E; Brennan, Sean; Bridges, John; Brownlee, Don E; Bullock, Emma S; Burghammer, Manfred; Clark, Benton C; Dai, Zu Rong; Daghlian, Charles P; Djouadi, Zahia; Fakra, Sirine; Ferroir, Tristan; Floss, Christine; Franchi, Ian A; Gainsforth, Zack; Gallien, Jean-Paul; Gillet, Philippe; Grant, Patrick G; Graham, Giles A; Green, Simon F; Grossemy, Faustine; Heck, Philipp R; Herzog, Gregory F; Hoppe, Peter; Hörz, Friedrich; Huth, Joachim; Ignatyev, Konstantin; Ishii, Hope A; Janssens, Koen; Joswiak, David; Kearsley, Anton T; Khodja, Hicham; Lanzirotti, Antonio; Leitner, Jan; Lemelle, Laurence; Leroux, Hugues; Luening, Katharina; Macpherson, Glenn J; Marhas, Kuljeet K; Marcus, Matthew A; Matrajt, Graciela; Nakamura, Tomoki; Nakamura-Messenger, Keiko; Nakano, Tsukasa; Newville, Matthew; Papanastassiou, Dimitri A; Pianetta, Piero; Rao, William; Riekel, Christian; Rietmeijer, Frans J M; Rost, Detlef; Schwandt, Craig S; See, Thomas H; Sheffield-Parker, Julie; Simionovici, Alexandre; Sitnitsky, Ilona; Snead, Christopher J; Stadermann, Frank J; Stephan, Thomas; Stroud, Rhonda M; Susini, Jean; Suzuki, Yoshio; Sutton, Stephen R; Taylor, Susan; Teslich, Nick; Troadec, D; Tsou, Peter; Tsuchiyama, Akira; Uesugi, Kentaro; Vekemans, Bart; Vicenzi, Edward P; Vincze, Laszlo; Westphal, Andrew J; Wozniakiewicz, Penelope; Zinner, Ernst; Zolensky, Michael E

    2006-12-15

    We measured the elemental compositions of material from 23 particles in aerogel and from residue in seven craters in aluminum foil that was collected during passage of the Stardust spacecraft through the coma of comet 81P/Wild 2. These particles are chemically heterogeneous at the largest size scale analyzed ( approximately 180 ng). The mean elemental composition of this Wild 2 material is consistent with the CI meteorite composition, which is thought to represent the bulk composition of the solar system, for the elements Mg, Si, Mn, Fe, and Ni to 35%, and for Ca and Ti to 60%. The elements Cu, Zn, and Ga appear enriched in this Wild 2 material, which suggests that the CI meteorites may not represent the solar system composition for these moderately volatile minor elements.

  14. Modeling dental composite shrinkage by digital image correlation and finite element methods

    Science.gov (United States)

    Chen, Terry Yuan-Fang; Huang, Pin-Sheng; Chuang, Shu-Fen

    2014-10-01

    Dental composites are light-curable resin-based materials with an inherent defect of polymerization shrinkage which may cause tooth deflection and debonding of restorations. This study aimed to combine digital image correlation (DIC) and finite element analysis (FEA) to model the shrinkage behaviors under different light curing regimens. Extracted human molars were prepared with proximal cavities for composite restorations, and then divided into three groups to receive different light curing protocols: regular intensity, low intensity, and step-curing consisting of low and high intensities. For each tooth, the composite fillings were consecutively placed under both unbonded and bonded conditions. At first, the shrinkage of the unbonded restorations was analyzed by DIC and adopted as the setting of FEA. The simulated shrinkage behaviors obtained from FEA were further validated by the measurements in the bonded cases. The results showed that different light curing regimens affected the shrinkage in unbonded restorations, with regular intensity showing the greatest shrinkage strain on the top surface. The shrinkage centers in the bonded cases were located closer to the cavity floor than those in the unbonded cases, and were less affected by curing regimens. The FEA results showed that the stress was modulated by the accumulated light energy density, while step-curing may alleviate the tensile stress along the cavity walls. In this study, DIC provides a complete description of the polymerization shrinkage behaviors of dental composites, which may facilitate the stress analysis in the numerical investigation.

  15. STRESS ANALYSIS OF COMPOSITE PROPELLER BY USING FINITE ELEMENT ANALYSIS

    Directory of Open Access Journals (Sweden)

    B.SRIDHAR REDDY

    2012-08-01

    Full Text Available Present work proposes a methodology to design a propeller with a metal and composite material to analyze its strength and deformation using Ansys software. In order to evaluate the effectiveness of composite over metals, stress analysis is performed on both composite and metal propeller using Ansys. Proposed methodology showed substantial improvements in metal propellers. The mean deflection, normal stress and shear stress were found for both metallic and composite propeller by using Ansys. From the results, stressanalysis composite propeller is safe resonance phenomenon. In this work effort is made to reduce stress levels so that advantage of weight reduction along with stresses can be obtained. The comparison analysis of metallic and composite propeller was made for the maximum deformation and normal stresses.

  16. Advanced Manufacturing Technologies (AMT): Composites Integrated Modeling Element

    Data.gov (United States)

    National Aeronautics and Space Administration — CIM encompassed computational methods, tools and processes that go into the materials, design, manufacturing and qualification of composite aerospace structures....

  17. Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

    Science.gov (United States)

    Gao, Xiujie; Burton, Deborah; Turner, Travis L.; Brinson, Catherine

    2005-01-01

    Shape memory alloy hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam. Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on the beam. The thermomechanical behavior of these composites was simulated in ABAQUS using user-defined SMA elements. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. Keywords: shape memory alloys, Nitinol, ABAQUS, finite element analysis, post-buckling control, shape control, deflection control, adaptive stiffening, morphing, constitutive modeling, user element

  18. RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD AND ITS VERIFICATION FOR EFFECTIVE PROPERTIES OF COMPOSITE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The present study aims at developing a new method-Random M icrostructure Finite Element Method (RMFEM)for the effective properties of composite materials . In this method, a random microstructure model is used to simulate the microstructure of the real composite materials. The physical fields in such a randm microstructure model under specified boundary and initial conditions are analyzed by finite element method. The effective properties of composite materials can be obtained from the analysis results. As verification, some effective properties of composite materials, such as elastic module,thermal expansion coefficient, thermal conductivity and elastoplastic properties, are investigated by random microstructure finite element method. The numerical results are given together with the experimental data. It i- revealed that the random microstructure finite element method is a very valid method for the determination of the effective properties of composite materials.

  19. An integrated encyclopedia of DNA elements in the human genome.

    Science.gov (United States)

    2012-09-01

    The human genome encodes the blueprint of life, but the function of the vast majority of its nearly three billion bases is unknown. The Encyclopedia of DNA Elements (ENCODE) project has systematically mapped regions of transcription, transcription factor association, chromatin structure and histone modification. These data enabled us to assign biochemical functions for 80% of the genome, in particular outside of the well-studied protein-coding regions. Many discovered candidate regulatory elements are physically associated with one another and with expressed genes, providing new insights into the mechanisms of gene regulation. The newly identified elements also show a statistical correspondence to sequence variants linked to human disease, and can thereby guide interpretation of this variation. Overall, the project provides new insights into the organization and regulation of our genes and genome, and is an expansive resource of functional annotations for biomedical research.

  20. Element Partitioning Constraints on Formation and Composition of the Earth's Core

    Science.gov (United States)

    Li, J.; Agee, C. B.; Fei, Y.

    1998-01-01

    Element partitioning study provides a number of constraints on the formation and composition of the core. First, partitioning of siderophile elements between the core and mantle should explain the "excess" siderophile elements in the mantle. Second, partitioning of light element(s) between the core and mantle should supply the core with the right amount of light element(s) to account for the density deficit in the core. Third, partitioning of light element(s) between the inner and outer core should be consistent with the observed difference in density deficits (relative to pure Fe) between these two reservoirs. In this study, high-pressure and high-temperature experiments have been conducted to investigate the pressure, temperature, and composition effects on partitioning of siderophile elements Ni and Co between core-forming Fe alloy and mantle silicate melt and minerals, partitioning of light elements S, O, and Si between core-forming Fe alloy and mantle silicate melt and minerals, and partitioning of light elements S and C between solid and liquid Fe. The implications of these results for mechanism of core formation and the composition of the core are discussed.

  1. Calibration of a finite element composite delamination model by experiments

    DEFF Research Database (Denmark)

    Gaiotti, M.; Rizzo, C.M.; Branner, Kim;

    2013-01-01

    distinct sub-laminates. The work focuses on experimental validation of a finite element model built using the 9-noded MITC9 shell elements, which prevent locking effects and aiming to capture the highly non linear buckling features involved in the problem. The geometry has been numerically defined...... modes related to the production methods is presented in this paper. A microscopic analysis of the fracture surfaces was carried out in order to better understand the failure mechanisms. © 2013 Taylor & Francis Group....

  2. Three-dimensional finite element simulation of intermingled-fiber hybrid composite behavior

    Science.gov (United States)

    Mital, Subodh K.; Chamis, Christos C.

    1992-01-01

    Three-dimensional finite element methods and the intraply hybrid micromechanics equations are used to predict composite properties for a unidirectional graphite-epoxy primary composite with S-glass fibers used as hybridizing fibers. The micromechanics equations are embedded in a computer code ICAN (Integrated Composites Analyzer). The three-dimensional finite element model consists of three-by-three unit cell array, with a total fiber volume ratio of 0.54. There is a good agreement between the composite properties and microstresses obtained from both methods. The results indicate that the finite element methods and micromechanics equations can be used to obtain the properties of intermingled hybrid composites needed for analysis/design of hybrid composite structures.

  3. Isotopic and Elemental Composition of Roasted Coffee as a Guide to Authenticity and Origin.

    Science.gov (United States)

    Carter, James F; Yates, Hans S A; Tinggi, Ujang

    2015-06-24

    This study presents the stable isotopic and elemental compositions of single-origin, roasted coffees available to retail consumers. The δ(13)C, δ(15)N, and δ(18)O compositions were in agreement with those previously reported for green coffee beans. The δ(15)N composition was seen to be related to organic cultivation, reflected in both δ(2)H and δ(18)O compositions. The δ(13)C composition of extracted caffeine differed little from that of the bulk coffee. Stepwise discriminant analysis with jackknife tests, using isotopic and elemental data, provided up to 77% correct classification of regions of production. Samples from Africa and India were readily classified. The wide range in both isotopic and elemental compositions of samples from other regions, specifically Central/South America, resulted in poor discrimination between or within these regions. Simpler X-Y and geo-spatial plots of the isotopic data provided effective visual means to distinguish between coffees from different regions.

  4. Human Exposure and Health Effects of Inorganic and Elemental Mercury

    Science.gov (United States)

    Zheng, Wei

    2012-01-01

    Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety. PMID:23230464

  5. Major element chemical compositions of chondrules in unequilibrated chondrites

    Science.gov (United States)

    Ikeda, Y.

    1984-01-01

    The chemical compositions (except for metals and sulfides in chondrules) of more than 500 chondrules from unequilibrated E, H, L, LL, and C chondrites were measured using a broad beam of an electron-probe microanalyzer. The compositions of chondrules can be represented by various mixtures of normative compositions of olivine, low-Ca pyroxene, plagioclase, and high-Ca pyroxene with minor amounts of spinel, feldspathoid, SiO2-minerals, etc., indicating that the chondrule precursor materials consisted of aggregates of these minerals. The Al, Na, and K contents of most chondrules reflect the compositions of the ternary feldspar (An-Ab-Kf) of the chondrule precursor materials, and chemical types of chondrules (KF, SP, IP, and CP) are defined on the basis of the atomic proportion of Al, Na, and K.

  6. Trace element distribution in human teeth by x-ray fluorescence spectrometry and multivariate statistical analysis

    CERN Document Server

    Oprea, Cristiana; Gustova, Marina V; Oprea, Ioan A; Buzguta, Violeta L

    2014-01-01

    X-ray fluorescence spectrometry (XRFS) was used as a multielement method of evaluation of individual whole human tooth or tooth tissues for their amounts of trace elements. Measurements were carried out on human enamel, dentine, and dental cementum, and some differences in tooth matrix composition were noted. In addition, the elemental concentrations determined in teeth from subjects of different ages, nutritional states, professions and gender, living under various environmental conditions and dietary habits, were included in a comparison by multivariate statistical analysis (MVSA) methods. By factor analysis it was established that inorganic components of human teeth varied consistently with their source in the tissue, with more in such tissue from females than in that from males, and more in tooth incisor than in tooth molar.

  7. Elemental (C, H, N) composition of zooplankton from north Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Matondkar, S.G.P.; Bhat, K.L.; Ansari, Z.A.; Parulekar, A.H.

    Zooplankton samples collected from north Arabian Sea during March 1992 were analysed for elemental (C,H,N) composition. Estimated carbon, hydrogen and nitrogen concentrations displayed variations among different groups but their ratios were nearly...

  8. METHODS OF THE APPROXIMATE ESTIMATIONS OF FATIGUE DURABILITY OF COMPOSITE AIRFRAME COMPONENT TYPICAL ELEMENTS

    Directory of Open Access Journals (Sweden)

    V. E. Strizhius

    2015-01-01

    Full Text Available Methods of the approximate estimations of fatigue durability of composite airframe component typical elements which can be recommended for application at the stage of outline designing of the airplane are generated and presented.

  9. Finite element analysis of a composite artificial ankle

    Science.gov (United States)

    Perkins, Leigh Ann; Johnston, Lawrence; Denniston, Charles; Czekalski, Blaise E.

    1993-01-01

    Ultra-light carbon fiber composite materials are being utilized in artificial limbs with increasing frequency in recent years. Dr. Arthur Copes, an orthotist from Baton Rouge, Louisiana, has developed a graphite expoxy composite material artificial ankle (Copes/Bionic Ankle) that is intended to be used by amputees who require the most advanced above-and-below-the-knee prosthetic devices. The Copes/Bionic Ankle is designed to reproduce the function of the natural ankle joint by allowing the composite material to act as a spring mechanism without the use of metal mechanical parts. NASA Marshall Space Flight Center has agreed to participate in the design effort by providing the structural analysis of the artificial ankle design.

  10. Postmodern landscape architecture: theoretical, compositional characteristics and design elements with the analysis of 25 projects

    OpenAIRE

    Eplényi Anna; Oláh-Christian Brigitta

    2015-01-01

    This paper endeavours to highlight three aspects of postmodern landscape design: theoretical basis, composition and design elements. Postmodern theories, philosophy influenced the language of the postmodern landscape architecture and got materialized in the use of narratives, eclecticism, the Rhizome-principle. Postmodern landscape composition can be associated with anti-hierarchy, unusual structures, landforms, and playful moods. Postmodern design elements consist of the strong graphical use...

  11. DEFINING ELEMENTAL COMPOSITION OF VEGETABLE HYDROCOLLOIDS USING THE ELECTRON PROBE MICROANALYSIS METHOD

    OpenAIRE

    2014-01-01

    In production of soft capsules, natural and semi-synthetic vegetative analogues for pharmaceutical gelatin are used. This work is devoted to defining elemental composition of vegetative analogs for pharmaceutical gelatin using the electron probe microanalysis method. The electron probe microanalysis is one of the most popular methods of quantitative and semi-quantitative nondestructive elemental analysis. Spectrometric profiles are described for defining the composition of carboxymethylcellul...

  12. Advanced Design of Composite Steel-Concrete Structural element

    Directory of Open Access Journals (Sweden)

    Dr. D. R. Panchal

    2014-07-01

    Full Text Available Composite framing system consisting of steel beams acting interactively with metal deck-concrete slab and concrete encased composite columns, has been as a viable alternative to the conventional steel or reinforced concrete system in the high-rise construction. However, in Indian context, it is comparatively new and no appropriate design codes are available for the same. Complications in the analysis and design of composite structures have led numerous researchers to develop simplified methods so as to eliminate a number of large scale tests needed for the design. In the present work, a simplified method of composite slabs, beams and columns design is used and software is developed with pre- and post- processing facilities in VB.NET. All principal design checks are incorporated in the software. The full and partial shear connection and the requirement for transverse reinforcement are also considered. To facilitate direct selection of steel section, a database is prepared and is available at the back end with the properties of all standard steel sections. Screen shots are included in the paper to illustrate the method employed for selecting the appropriate section and shear connectors and thus to verify the design adequacy.

  13. Transposable element insertions have strongly affected human evolution.

    Science.gov (United States)

    Britten, Roy J

    2010-11-16

    Comparison of a full collection of the transposable element (TE) sequences of vertebrates with genome sequences shows that the human genome makes 655 perfect full-length matches. The cause is that the human genome contains many active TEs that have caused TE inserts in relatively recent times. These TE inserts in the human genome are several types of young Alus (AluYa5, AluYb8, AluYc1, etc.). Work in many laboratories has shown that such inserts have many effects including changes in gene expression, increases in recombination, and unequal crossover. The time of these very effective changes in the human lineage genome extends back about 4 million years according to these data and very likely much earlier. Rapid human lineage-specific evolution, including brain size is known to have also occurred in the last few million years. Alu insertions likely underlie rapid human lineage evolution. They are known to have many effects. Examples are listed in which TE sequences have influenced human-specific genes. The proposed model is that the many TE insertions created many potentially effective changes and those selected were responsible for a part of the striking human lineage evolution. The combination of the results of these events that were selected during human lineage evolution was apparently effective in producing a successful and rapidly evolving species.

  14. NOTION, ELEMENTS AND EVALUATION OF HUMAN RESOURCES MANAGMENT IN SPORT

    Directory of Open Access Journals (Sweden)

    Milorad M. Drobac

    2009-11-01

    Full Text Available Principal object of the author’s research in work is identification of notion, cru- cial elements and evaluation of human resources management in general and apart in sport. From the beginning of usage of term “human resources management”, we use foretoken “strategic” that has especially signified meaning. Strategic approach to the exploration of this problem points to the fact that human resources are from particularly significance for all forms of human organization (firms, associations, institutions etc., regardless are we talking about economy, social activity, politics, science, sport or any other area of human activity. Experience shows that, in our society, we mainly considered human resources management from the aspect of formulation and implementation of strategy in any shape and segment of altogether human activity, but we pay a little interest to the control, or in other words evaluation of human resources performance. What is attained in world rela- tions, on the human resources management plan, admonish and binds that we must ac- cept employees in our environment (it implies sport as an equal partner in management

  15. Distributions of sulphur and other elements in human hair follicles

    Energy Technology Data Exchange (ETDEWEB)

    Ollerhead, R.W.; Legge, G.J.F.; Jones, L.N.

    1989-04-01

    Distributions of sulphur and other elements have been measured in several different specimens of human hair follicles. Whole specimens, longitudinal bisections, and 10 /mu/m thick longitudinal sections have been analyzed by PIXE using the Melbourne scanning proton microprobe. Elemental maps consistently showed that sulphur contents of the presumptive hair shaft (PHS) were uniformly low from 0 to 400 /mu/m (bulb end), increased continuously from about 400 to 800 /mu/m, and reached a plateau. Sulphur levels were uniformly low in the inner rooth sheath. These observations are consistent with previous protein analysis of PHS sections, indicating sequential synthesis of the major classes of keratin proteins. Maps of other elements indicated that Si, Ca, and Fe tended to be concentrated randomly, whereas, P, Cl, K, and Zn were more uniformly distributed. Average relative concentrations of Si, P, Cl, K, Ca, Fe, Cu, and Zn were estimated from total X-ray spectra. (orig.).

  16. Use of human MAR elements to improve retroviral vector production.

    Science.gov (United States)

    Buceta, M; Galbete, J L; Kostic, C; Arsenijevic, Y; Mermod, N

    2011-01-01

    Retroviral vectors have many favorable properties for gene therapies, but their use remains limited by safety concerns and/or by relatively lower titers for some of the safer self-inactivating (SIN) derivatives. In this study, we evaluated whether increased production of SIN retroviral vectors can be achieved from the use of matrix attachment region (MAR) epigenetic regulators. Two MAR elements of human origin were found to increase and to stabilize the expression of the green fluorescent protein transgene in stably transfected HEK-293 packaging cells. Introduction of one of these MAR elements in retroviral vector-producing plasmids yielded higher expression of the viral vector RNA. Consistently, viral titers obtained from transient transfection of MAR-containing plasmids were increased up to sixfold as compared with the parental construct, when evaluated in different packaging cell systems and transfection conditions. Thus, use of MAR elements opens new perspectives for the efficient generation of gene therapy vectors.

  17. A First Assessment of the Elemental Composition of Atmospheric Aerosols in the Canadian Oil Sands Region

    Directory of Open Access Journals (Sweden)

    Dabek-Zlotorzynska E.

    2013-04-01

    Full Text Available Canadian Oil Sands, which comprise 97% of Canada’s 176 billion barrels of proven oil reserves, are located beneath 140,200 km2 of boreal forests, prairies and wetlands, and are the second largest known deposit of crude oil in the world. As such, this region has experienced rapid industrial development, which resulted also in increasing industrial air emissions, primarily from bitumen upgrading and mine vehicle fleet operations. This rapid development has led to concerns regarding health risk to humans, and other terrestrial and aquatic wildlife associated with exposure to toxic contaminants, especially metals and polycyclic aromatic compounds (PACs particularly along the Athabasca River and its watershed. Canada’s Minister of the Environment announced that Environment Canada (EC will jointly lead, in collaboration with Government of Alberta and relevant stakeholders, the development and implementation of an enhanced monitoring system in the Oil Sands region to provide information on the state of the air, water, land andbiodiversity. This work presents preliminary data on the first assessment of elemental composition of fine particulate matter (particles<2.5 mm in diameter; PM2.5 at 3 air quality sites in close proximity to Oil Sands processing activities. Since December 2010, integrated 24 hour air samples were collected every sixth day on a 47-mm Teflon filters using Thermo Fisher Partisol 2000-FRM samplers operated by the National Air Pollution Surveillance (NAPS network that involves EC and the Canadian provinces and territories. All samples including laboratory, travel and field blanks were subjected to gravimetric determination of PM2.5 mass and energy dispersive X-ray fluorescence (ED-XRF analysis for 46 elements. Since ED-XRF is a non-destructive technique, PM2.5 samples were subsequently analyzed for 37 trace elements including rare earth elements using inductively-coupled plasma mass spectrometry (ICP-MS combined with microwave

  18. Elemental composition method for computation and analysis of simultaneous chemical and phase equilibrium

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    An elemental composition method for computation and analysis of simultaneous chemical and phase equilibrium (CPE) of non-ideal mixtures is proposed. The concept of element is defined, the relationship between component composition and elemental composition is derived, and the concept of elemental potential and its physical meaning are further cleared from the view point of thermodynamics. The relationship between chemical potential and elemental potential is derived in the thermodynamic principles, and the computation equations for CPE problem are obtained based on elemental potential. A simple form of necessary and sufficient condition in terms of elemental composition for reactive azeotropes is derived, which takes the same functional form as the condition for azeotropes in non-reactive systems. The element in this note may be atoms, molecules or group radicals. The presented method is applicable to CPE problem of non-ideal mixtures, and the computation can be simplified by the dimension reducing method. The presented method was supplied to compute and analyze CPE problem of several examples and it is found that it is a robust and efficient method.

  19. Determination of trace elements in the human substantia nigra

    Energy Technology Data Exchange (ETDEWEB)

    Morawski, M. [Paul-Flechsig-Institut fuer Hirnforschung, Universitaet Leipzig, Jahnallee 59, 04109 Leipzig (Germany)]. E-mail: morm@medizin.uni-leipzig.de; Meinecke, Ch. [Fakultaet fuer Physik und Geowissenschaften, Universitaet Leipzig, Linnestrasse 5, 04105 Leipzig (Germany); Reinert, T. [Fakultaet fuer Physik und Geowissenschaften, Universitaet Leipzig, Linnestrasse 5, 04105 Leipzig (Germany); Doerffel, A.C. [Paul-Flechsig-Institut fuer Hirnforschung, Universitaet Leipzig, Jahnallee 59, 04109 Leipzig (Germany); Riederer, P. [Klin. Neurochemie, Abt. Psychiatrie, Universitaet Wuerzburg, Fuechsleinstrasse 15, 97080 Wuerzburg (Germany); Arendt, T. [Paul-Flechsig-Institut fuer Hirnforschung, Universitaet Leipzig, Jahnallee 59, 04109 Leipzig (Germany); Butz, T. [Fakultaet fuer Physik und Geowissenschaften, Universitaet Leipzig, Linnestrasse 5, 04105 Leipzig (Germany)

    2005-04-01

    'The gain in brain is mainly in the stain' was long time a key sentence for research in neurodegenerative disease. However, for a quantification of the element concentrations (especially iron) in brain tissue, standard staining methods are insufficient. Advanced physical methods allow a quantitative elemental analysis of brain tissue. The sophisticated ion beam analysis provides a quantitative determination of elemental concentrations with a subcellular spatial resolution using a scanning proton beam focussed down to below 1 {mu}m that induces characteristic X-rays in the specimen (PIXE - particle induced X-ray emission). Histochemical and biochemical determinations of total iron content in brain regions from idiopathic Parkinson's disease have demonstrated an increase of iron in parkinsonian substantia nigra pars compacta but not in the pars reticulata, however without a clear cellular classification. For the first time, we have differentially investigated the intra- and extraneuronal elemental concentrations (especially iron) of the human substantia nigra pars compacta versus pars reticulata with detection limits in the range of 50 {mu}mol/l. Thus, we could compare the neuronal iron concentration in human brain sections of healthy and parkinsonian brain tissue. Clear differences in the iron concentration and distribution could be disclosed. Additionally, we could show in situ that the increased intraneuronal iron content is linked to neuromelanin.

  20. Finite element procedure for stress amplification factor recovering in a representative volume of composite materials

    Directory of Open Access Journals (Sweden)

    Paulo Cesar Plaisant Junior

    2011-09-01

    Full Text Available Finite element models are proposed to the micromechanical analysis of a representative volume of composite materials. A detailed description of the meshes, boundary conditions, and loadings are presented. An illustrative application is given to evaluate stress amplification factors within a representative volume of the unidirectional carbon fiber composite plate. The results are discussed and compared to the numerical findings.

  1. Finite element modeling of small-scale tapered wood-laminated composite poles with biomimicry features

    Science.gov (United States)

    Cheng Piao; Todd F. Shupe; R.C. Tang; Chung Y. Hse

    2008-01-01

    Tapered composite poles with biomimicry features as in bamboo are a new generation of wood laminated composite poles that may some day be considered as an alternative to solid wood poles that are widely used in the transmission and telecommunication fields. Five finite element models were developed with ANSYS to predict and assess the performance of five types of...

  2. Alkali elemental and potassium isotopic compositions of Semarkona chondrules

    Science.gov (United States)

    Alexander, C.M. O'D.; Grossman, J.N.

    2005-01-01

    We report measurements of K isotope ratios in 28 Semarkona chondrules with a wide range of petrologic types and bulk compositions as well as the compositions of CPX-mesostasis pairs in 17 type I Semarkona chondrules, including two chondrules with radial alkali zonation and 19 type II chondrules. Despite the wide range in K/Al ratios, no systematic variations in K isotopic compositions were found. Semarkona chondrules do not record a simple history of Rayleigh-type loss of K. Experimentally determined evaporation rates suggest that considerable alkali evaporation would have occurred during chondrule formation. Nevertheless, based on Na CPX-mesostasis distribution coefficients, the alkali contents of the cores of most chondrules in Semarkona were probably established at the time of final crystallization. However, Na CPX-mesostasis distribution coefficients also show that alkali zonation in type I Semarkona chondrules was produced by entry of alkalis after solidification, probably during parent body alteration. This alkali metasomatism may have gone to completion in some chondrules. Our preferred explanation for the lack of systematic isotopic enrichments, even in alkali depleted type I chondrule cores, is that they exchanged with the ambient gas as they cooled. ?? The Meteoritical Society, 2005.

  3. Determining the elemental composition of fuels by bomb calorimetry and the inverse correlation of HHV with elemental composition

    DEFF Research Database (Denmark)

    Bech, Niels; Jensen, Peter Arendt; Dam-Johansen, Kim

    2009-01-01

    This article presents a method to obtain a simplified elemental analysis of an organic sample in which oxygen, nitrogen, and sulphur are lumped. The method uses a bomb calorimeter, water, and ash measurements combined with a numerical procedure based on a generalised equation for predicting highe...

  4. NUMERICAL SIMULATION OF 2D FIBER-REINFORCED COMPOSITES USING BOUNDARY ELEMENT METHOD

    Institute of Scientific and Technical Information of China (English)

    KONG Fan-zhong; ZHENG Xiao-ping; YAO Zhen-han

    2005-01-01

    The boundary element method was improved for the 2D elastic composites with randomly distributed inclusions. This problem can be reduced to a boundary integral equation for a multi-connected domain. Further, considering the matrices of the tractions and displacements for each group of the identical inclusion were the same, an effective computational scheme was designed, since the orders of the resulting matrix equations can be greatly reduced. Numerical examples indicate that this boundary element method scheme is more effective than the conventional multi-domain boundary element method for such a problem. The present scheme can be used to investigate the effective mechanical properties of the fiber-reinforced composites.

  5. Determination of element composition of three lichens and their distribution in King George Island, Antarctica

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cross-section slices of Usnea antarctica Du Rietz, Usnea aurantiaco-atra (Jacq.) Bory. and Cladonia sp. at upper, middle and basal positions were prepared, respectively. The element composition and relative content were determined by SEM and EDS at the surface, intermediate and inner layers in each slice, respectively. The result indicated that the composition of element is mostly same in these lichens. The relative content of Al, Si, K and Ca elements is high, and P is close at each position. The result is of benefit to study the structure and physiological characteristics of lichens, and to analyze geological environment in Antarctica.

  6. Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures

    Science.gov (United States)

    Vlahopoulos, Nickolas; Schiller, Noah H.

    2011-01-01

    The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

  7. COMGEN: A computer program for generating finite element models of composite materials at the micro level

    Science.gov (United States)

    Melis, Matthew E.

    1990-01-01

    COMGEN (Composite Model Generator) is an interactive FORTRAN program which can be used to create a wide variety of finite element models of continuous fiber composite materials at the micro level. It quickly generates batch or session files to be submitted to the finite element pre- and postprocessor PATRAN based on a few simple user inputs such as fiber diameter and percent fiber volume fraction of the composite to be analyzed. In addition, various mesh densities, boundary conditions, and loads can be assigned easily to the models within COMGEN. PATRAN uses a session file to generate finite element models and their associated loads which can then be translated to virtually any finite element analysis code such as NASTRAN or MARC.

  8. Study of the stress-strain state of compressed concrete elements with composite reinforcement

    Directory of Open Access Journals (Sweden)

    Bondarenko Yurii

    2017-01-01

    Full Text Available The efficiency analysis of the application of glass composite reinforcement in compressed concrete elements as a load-carrying component has been performed. The results of experimental studies of the deformation-strength characteristics of this reinforcement on compression and compressed concrete cylinders reinforced by this reinforcement are presented. The results of tests and mechanisms of sample destruction have been analyzed. The numerical analysis of the stress-strain state has been performed for axial compression of concrete elements with glasscomposite reinforcement. The influence of the reinforcement percentage on the stressed state of a concrete compressed element with the noted reinforcement is estimated. On the basis of the obtained results, it is established that the glass-composite reinforcement has positive effect on the strength of the compressed concrete elements. That is, when calculating the load-bearing capacity of such structures, the function of composite reinforcement on compression should not be neglected.

  9. Experiments of Multi-element Composite Foundation with Steel Pipe Pile and Gravel Pile

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-zhi; ZHENG Jun-jie

    2008-01-01

    A set of self-developed apparatus for foundation physical model were utilized to conduct model tests of the multi-element composite foundation with a steel pipe pile and several gravel piles. Some load-bearing characteristics of the multi-element composite foundation, including the curves of foundation settlement, stresses of piles, pile-soil stress ratio, and load-sharing ratio of piles and soil, were obtained to study its working performances in silty sand soil. The experimental results revealed that the multi-element composite foundation with steel pipe pile and gravel pile contributed more than the gravel pile composite foundation in improving the bearing capacity of the silty fine sand.

  10. Tensile Properties of Surface-Treated Glass Fiber Reinforced PTFE Composite with Rare Earth Elements

    Institute of Scientific and Technical Information of China (English)

    薛玉君; 程先华

    2003-01-01

    The optimum amount of rare earth elements (RE) for treating glass fiber surface and its effect on the tensile properties of glass fiber reinforced polytetrafluoroethylene (GF/PTFE) composites were investigated. The tensile properties of GF/PTFE composites with different surface treatment conditions were measured. The fracture surface morphologies were observed and analyzed by SEM. The results indicate that rare earth elements can effectively promote the interfacial adhesion between the glass fiber and PTFE, owing to the effects of rare earth elements on the compatibility. The tensile properties of GF/PTFE composites can be improved considerably when the content of RE in surface modifier is 0.2%~0.4%, and the optimum performance of GF/PTFE composites is obtained at 0.3%RE content.

  11. Predictions of biochar yield and elemental composition during torrefaction of forest residues.

    Science.gov (United States)

    Bach, Quang-Vu; Chen, Wei-Hsin; Chu, Yen-Shih; Skreiberg, Øyvind

    2016-09-01

    In this work, a direct prediction method coupled with a consecutive reaction model is developed to estimate the biochar yield and elemental composition in a biomass torrefaction process. Norway forest residues were chosen as feedstock and torrefied at different temperatures under nitrogen atmosphere in a thermogravimetric analyzer. Obtained data were modeled to predict the mass loss during torrefaction. Distributions of initial, intermediate and final solid products as well as torrefaction kinetic parameters are reported. Thereafter, a direct method to predict the elemental composition of biochar is introduced. The results show that the decomposition of initial biomass to form an intermediate solid has higher conversion rate than the degradation of the intermediate. Moreover, the predictions reproduce well the experimental thermogravimetric curves and show composition trends similar to the literature data. This method is useful for the design and optimization of industrial torrefaction processes with predictable biochar yield and elemental composition.

  12. Experimental determination of elemental compositions and densities of several common liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Barquero, Leonor, E-mail: l.barquero@ciemat.e [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Avenida Complutense, 22, 28040 Madrid (Spain); Los Arcos, Jose M., E-mail: jm.losarcos@ciemat.e [Laboratorio de Metrologia de Radiaciones Ionizantes, CIEMAT, Avenida Complutense, 22, 28040 Madrid (Spain)

    2010-07-15

    New accurate data for the density and the elemental composition of several common liquid scintillators have been determined in this work. These data can be used to correctly determine or calculate the counting efficiency of radio-nuclides as well as to evaluate more accurately the uncertainties in LSC measurements due to variability on the composition of scintillators. The discrepancy between nominal densities at 20{sup o}C and the real densities at 20{sup o}C or 16{sup o}C can reach up to 4% among different batches of commercial scintillators all having the same nominal composition. Also significant differences in the elemental composition of commercial cocktails have been found compared to the nominal values. These differences range from 2% up to 260% depending on the element and the scintillator being measured.

  13. Sterol regulatory element binding transcription factor 1 (SREBF1) polymorphism and milk fatty acid composition.

    Science.gov (United States)

    Nafikov, R A; Schoonmaker, J P; Korn, K T; Noack, K; Garrick, D J; Koehler, K J; Minick-Bormann, J; Reecy, J M; Spurlock, D E; Beitz, D C

    2013-04-01

    Milk is known to contain high concentrations of saturated fatty acids-such as palmitic (16:0), myristic (14:0), and lauric (12:0) acids-that can raise plasma cholesterol in humans, making their presence in milk undesirable. The main objective of our candidate gene study was to develop genetic markers that can be used to improve the healthfulness of bovine milk. The sterol regulatory element binding transcription factor 1 (SREBF1) known to regulate the transcription of lipogenic genes together with SREBF chaperone and insulin induced gene 1 were the candidate genes. The results showed significant association of the overall SREBF1 haplotypes with milk production and variations in lauric (12:0) and myristic (14:0) acid concentrations in milk. Haplotype H1 of SREBF1 was the most desirable to improve milk healthfulness because it was significantly associated with lower lauric (12:0) and myristic (14:0) acid concentrations compared with haplotype H3 of SREBF1, and lower lauric acid (12:0) concentration compared with haplotype H2 of SREBF1. Haplotype H1 of SREBF1, however, was significantly associated with lower milk production compared with haplotype H3 of SREBF1. We did not detect any significant associations between genetic polymorphisms in insulin induced gene 1 (INSIG1) and SREBF chaperone and milk fatty acid composition. In conclusion, genetic polymorphisms in SREBF1 can be used to develop genetic tools for the selection of animals producing milk with healthier fatty acid composition.

  14. Structural elements of construction of individual and group exercises’ competition compositions in calisthenics

    Directory of Open Access Journals (Sweden)

    Kovalenko Y.O.

    2016-02-01

    Full Text Available Purpose: to analyze content of individual and group exercises’ competition compositions in calisthenics. Material: in the research HEEs’ girl students (n=20, junior sportswomen (n=10, experts (n=30, coaches with 10-40 years’ working experience participated. Results: it was found that temporary indicators permit to assess level of female gymnasts’ readiness for fulfillment of competition compositions’ elements; facilitated rational correlation of body and object’s elements of complexity. Quickness of preparation to elements and directly time of exercise’s fulfillment acquire great importance. In individual and group exercises the most important are distribution of sportswoman’s moving on all site with frequent change of directions. It was established that realization of structural elements facilitates full opening of female gymnast’s artistic image. Conclusions: for building of competition compositions coaches shall fully use indicators of space and time structural elements.

  15. Micro—PIXE analysis of trace element composition and their distribution in minerals of mantle peridotite

    Institute of Scientific and Technical Information of China (English)

    陈友红; 张旗; 等

    1996-01-01

    The proton microprobe and the quantitative micro-PIXE analysis technique are used to determine trace element composition and distribution in minerals of mantle peridotite,therefore,additional useful information is provided on the study of upper mantle mineral phase transformation.An example reported here is the study on the geochemical behavior of trace elements in minerals of Suoluoshu mantle peridotite from Shandong province,which was in the process of mineral phase transformation from spinel to garnet.The study shows that trace element composition and distribution display obvious change in minerals while the mineral phase is transformed from spinel to garnet.Most of the trace elements analyzed reside in clinopyroxene and spinel.However,garnet is nearly poor in all of these elements.This phenomenon is associated with the infiltration of soultion and the existence of micropgrained inclusions in minerals in the process of mantle metasomatism.

  16. Simulation Studies on the Settlement of Composite Foundation with Contact Element of Zero Thickness

    Institute of Scientific and Technical Information of China (English)

    Dong Bichang; Wang Jingtao; Cheng Tao

    2005-01-01

    The various factors influencing the settlement of composite foundation have been more completely studied through numerical simulation. The influence on the settlement of composite foundation of the geometry and mechanical properties of the pile, soil, cushion, and the interface between pile and soil have been investigated through computer simulation, in which the contact elements with zero thickness are used. Some valuable conclusions for the settlement of composite foundation have been obtained: (1) The method using the contact element of zero thickness is successful when used in the simulation of the settlement of composite foundation; (2) Among the factors influencing the settlement of composite foundation, the compression modulus of the soil is the largest, and the cohesion of the soil is the second largest; (3) The effects on settlement of the internal friction angle of the soil, the elastic modulus, the radius, and the length of the pile, and the elestic modulus of the cushion are also more obvious.

  17. Stress relieving behaviour of flowable composite liners: A finite element analysis.

    Science.gov (United States)

    Anatavara, Sarida; Sitthiseripratip, Kriskrai; Senawongse, Pisol

    2016-01-01

    The purpose of this study was to investigate the consequences of using flowable composite as a liner beneath class I resin composite restorations on polymerization shrinkage stress and occlusal force. Models of class I resin composite restorations were generated. A control model received no flowable composite liner. Thirteen test models received different flowable composite liners with varying elastic modulus. Finite element analysis was used. The polymerization shrinkage of the resin composite and an occlusal force were simulated in the models. The stress and strain energy density in each model were investigated. The results demonstrated that all flowable composite linings were able to reduce polymerization shrinkage stress and occlusal force in enamel, dentin, the hybrid layer, and the adhesive layer to various degrees in tooth-restoration systems. Therefore, additional techniques may be applied to reduce the remaining stress and to ensure the long-term success of restorations.

  18. New insight into transcription of human endogenous retroviral elements.

    Science.gov (United States)

    Pačes, Jan; Huang, Yao-Ting; Pačes, Václav; Rídl, Jakub; Chang, Chung-Ming

    2013-03-25

    It is generally assumed that human endogenous retroviral elements (HERVs) belong to the class of genomic repetitive nucleotide sequences often called 'junk DNA'. These elements were categorized to families, and members of some of these families (e.g. HERV-H, HERV-W and HERV-K) were shown to be transcribed. These transcriptions were associated with several severe diseases such as mental disorders, AIDS, autoimmune diseases and cancer. In this review we discuss several bioinformatics strategies for genome-wide scan of HERVs transcription using high-throughput RNA sequencing on several platforms. We show that many more HERVs than previously described are transcribed to various levels and we discuss possible implications of these transcriptions.

  19. Three-dimensional hybrid-stress finite element analysis of composite laminates with cracks and cutouts

    Science.gov (United States)

    Wang, S. S.

    1985-01-01

    A three-dimensional hybrid-stress finite element analysis of composite laminates containing cutouts and cracks is presented. Fully three-dimensional, hexahedral isoparametric elements of the hybrid-stress model are formulated on the basis of the Hellinger-Reissner variational principle. Traction-free edges, cutouts, and crack surfaces are modeled by imposition of exact traction boundary conditions along element surfaces. Special boundary and surface elements are constructed by introducing proper constraints on assumed stress functions. The Lagrangian multiplier technique is used to enforce ply-interface continuity conditions in hybrid bimaterial composite elements for modeling the interface region in a composite laminate. Two examples are given to illustrate the capability of the present method of approach: (1) the well-known delamination problem in an angle-ply laminate, and (2) the important problem of a composite laminate containing a circular hole. Results are presented in detail for each case. Implications of interlaminar and intralaminar crack initiation, growth and fracture in composites containing cracks and cutouts are discussed.

  20. Finite element code development for modeling detonation of HMX composites

    Science.gov (United States)

    Duran, Adam V.; Sundararaghavan, Veera

    2017-01-01

    In this work, we present a hydrodynamics code for modeling shock and detonation waves in HMX. A stable efficient solution strategy based on a Taylor-Galerkin finite element (FE) discretization was developed to solve the reactive Euler equations. In our code, well calibrated equations of state for the solid unreacted material and gaseous reaction products have been implemented, along with a chemical reaction scheme and a mixing rule to define the properties of partially reacted states. A linear Gruneisen equation of state was employed for the unreacted HMX calibrated from experiments. The JWL form was used to model the EOS of gaseous reaction products. It is assumed that the unreacted explosive and reaction products are in both pressure and temperature equilibrium. The overall specific volume and internal energy was computed using the rule of mixtures. Arrhenius kinetics scheme was integrated to model the chemical reactions. A locally controlled dissipation was introduced that induces a non-oscillatory stabilized scheme for the shock front. The FE model was validated using analytical solutions for SOD shock and ZND strong detonation models. Benchmark problems are presented for geometries in which a single HMX crystal is subjected to a shock condition.

  1. Multiscale Finite-Element Modeling of Sandwich Honeycomb Composite Structures

    Directory of Open Access Journals (Sweden)

    Yu. I. Dimitrienko

    2014-01-01

    Full Text Available The paper presents a developed multi-scale model of sandwich honeycomb structures. The model allows us both to calculate effective elastic-strength characteristics of honeycomb and forced covering of sandwich, and to find a 3D stress-strain state of structures using the threedimensional elastic theory for non- homogeneous media. On the basis of finite element analysis it is shown, that under four-point bending the maximal value of bending and shear stresses in the sandwich honeycomb structures are realized in the zone of applied force and plate support. Here the local stress maxima approximately 2-3 times exceed the “engineering” theoretical plate values of bending and shear stresses in the middle of panel. It is established that at tests for fourpoint bending there is a failure of the honeycomb sandwich panels because of the local adhesion failure rather than because of the covering exfoliation off the honeycomb core in the middle of panel.

  2. Stress analysis of composite spur gear using the finite element approach

    Science.gov (United States)

    Vijayarangan, S.; Ganesan, N.

    1993-03-01

    Engineering components made of composite materials find increasing applications ranging from spacecraft to small instruments. Many types of gear pump use composite gears, however little literature is available on their use. In this paper results obtained by static stress analysis of composite gears using a three-dimensional finite element approach are presented. Performance of two orthotropic material gears are presented and compared with mild steel gear. From the results it is concluded that composite material such as graphite/epoxy can be thought of as a material for power transmission gears.

  3. Predicting the mineral composition of dust aerosols: Insights from elemental composition measured at the Izaña Observatory

    Science.gov (United States)

    Pérez García-Pando, Carlos; Miller, Ron L.; Perlwitz, Jan P.; Rodríguez, Sergio; Prospero, Joseph M.

    2016-10-01

    Regional variations of dust mineral composition are fundamental to climate impacts but generally neglected in climate models. A challenge for models is that atlases of soil composition are derived from measurements following wet sieving, which destroys the aggregates potentially emitted from the soil. Aggregates are crucial to simulating the observed size distribution of emitted soil particles. We use an extension of brittle fragmentation theory in a global dust model to account for these aggregates. Our method reproduces the size-resolved dust concentration along with the approximately size-invariant fractional abundance of elements like Fe and Al in the decade-long aerosol record from the Izaña Observatory, off the coast of West Africa. By distinguishing between Fe in structural and free forms, we can attribute improved model behavior to aggregation of Fe and Al-rich clay particles. We also demonstrate the importance of size-resolved measurements along with elemental composition analysis to constrain models.

  4. Defining functional DNA elements in the human genome.

    Science.gov (United States)

    Kellis, Manolis; Wold, Barbara; Snyder, Michael P; Bernstein, Bradley E; Kundaje, Anshul; Marinov, Georgi K; Ward, Lucas D; Birney, Ewan; Crawford, Gregory E; Dekker, Job; Dunham, Ian; Elnitski, Laura L; Farnham, Peggy J; Feingold, Elise A; Gerstein, Mark; Giddings, Morgan C; Gilbert, David M; Gingeras, Thomas R; Green, Eric D; Guigo, Roderic; Hubbard, Tim; Kent, Jim; Lieb, Jason D; Myers, Richard M; Pazin, Michael J; Ren, Bing; Stamatoyannopoulos, John A; Weng, Zhiping; White, Kevin P; Hardison, Ross C

    2014-04-29

    With the completion of the human genome sequence, attention turned to identifying and annotating its functional DNA elements. As a complement to genetic and comparative genomics approaches, the Encyclopedia of DNA Elements Project was launched to contribute maps of RNA transcripts, transcriptional regulator binding sites, and chromatin states in many cell types. The resulting genome-wide data reveal sites of biochemical activity with high positional resolution and cell type specificity that facilitate studies of gene regulation and interpretation of noncoding variants associated with human disease. However, the biochemically active regions cover a much larger fraction of the genome than do evolutionarily conserved regions, raising the question of whether nonconserved but biochemically active regions are truly functional. Here, we review the strengths and limitations of biochemical, evolutionary, and genetic approaches for defining functional DNA segments, potential sources for the observed differences in estimated genomic coverage, and the biological implications of these discrepancies. We also analyze the relationship between signal intensity, genomic coverage, and evolutionary conservation. Our results reinforce the principle that each approach provides complementary information and that we need to use combinations of all three to elucidate genome function in human biology and disease.

  5. MODERN AND HUMAN DEVELOPMENT: DISCURSIVE ELEMENTS AND CONTROVERSIAL

    Directory of Open Access Journals (Sweden)

    Williams Aranguren Álvarez

    2015-11-01

    Full Text Available The purpose of this research is to analyze the discussion about modernity, postmodernism and liquid modernity and its relationship to human development, as an emerging element of the development model represented by modernity. This is done for a theoretical and documentary research, analyzing the discursive and controversial parts of the contributions of important authors in the field, arising mainly from sociology. It ends with contributions of useful ideas to continue the analysis and discussion on the subject, as part of a pending agenda that requires research and care in the field of social sciences.

  6. Unmasking the social engineer the human element of security

    CERN Document Server

    Hadnagy, Christopher

    2014-01-01

    Learn to identify the social engineer by non-verbal behavior Unmasking the Social Engineer: The Human Element of Security focuses on combining the science of understanding non-verbal communications with the knowledge of how social engineers, scam artists and con men use these skills to build feelings of trust and rapport in their targets. The author helps readers understand how to identify and detect social engineers and scammers by analyzing their non-verbal behavior. Unmasking the Social Engineer shows how attacks work, explains nonverbal communications, and demonstrates with visuals the c

  7. Have humans lost control: The elusive X-controlling element.

    Science.gov (United States)

    Peeters, Samantha B; Yang, Christine; Brown, Carolyn J

    2016-08-01

    The process of X-chromosome inactivation (XCI) randomly silences one of two X chromosomes in normal female cells. The ability to predict if there is a preference for one of the two Xs to be chosen (and survive) more often as the active X has important repercussions in human health and X-linked disease. Mice have a genetic component that modulates non-random skewing called the X-controlling element (Xce). Although the nature of the locus and its mechanisms of action are still under investigation, it is clear that different mouse strains carry unique Xce alleles on their X chromosomes, resulting in distinct skewing phenotypes in the F1 progeny of hybrid crosses. Whether a similar mechanism exists in humans is unclear, and challenges to identifying such a locus include the complexity and diversity of the human genome, the restricted time points and tissue(s) of examination in human subjects, and the lack of a model system recapitulating XCI in early development. In this review we consider the evidence for such a controlling locus in humans, in addition to discussing if we have the power to recognize it given the contribution of selective growth in causing skewed patterns of XCI.

  8. Elemental composition of Tibetan Plateau top soils and its effect on evaluating atmospheric pollution transport

    Energy Technology Data Exchange (ETDEWEB)

    Li Chaoliu [Institute of Tibetan Plateau Research, CAS, 18 Shuangqin Rd., Haidian District, Beijing 100085 (China); Kang Shichang, E-mail: shichang.kang@itpcas.ac.c [Institute of Tibetan Plateau Research, CAS, 18 Shuangqin Rd., Haidian District, Beijing 100085 (China); State Key Laboratory of Cryospheric Sciences, CAS, Lanzhou 730000 (China); Zhang Qianggong [Institute of Tibetan Plateau Research, CAS, 18 Shuangqin Rd., Haidian District, Beijing 100085 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)

    2009-08-15

    The Tibetan Plateau (TP) is an ideal place for monitoring the atmospheric environment of low to mid latitudes. In total 54 soil samples from the western TP were analyzed for major and trace elements. Results indicate that concentrations of some typical 'pollution' elements (such as As) are naturally high here, which may cause incorrect evaluation for the source region of these elements, especially when upper continental crust values are used to calculate enrichment factors. Because only particles <20 mum are transportable as long distances, elemental concentrations of this fraction of the TP soils are more reliable for the future aerosol related studies over the TP. In addition, REE compositions of the TP soils are unusual, highly characteristic and can be used as an effective index for identifying dust aerosol from the TP. - High concentrations of some elements of the Tibetan soils can cause incorrect evaluation for the source region of these elements during aerosol related study.

  9. Dynamic modeling and analysis of the PZT-bonded composite Timoshenko beams: Spectral element method

    Science.gov (United States)

    Lee, Usik; Kim, Daehwan; Park, Ilwook

    2013-03-01

    The health of thin laminated composite beams is often monitored using the ultrasonic guided waves excited by wafer-type piezoelectric transducers (PZTs). Thus, for the smart composite beams which consist of a laminated composite base beam and PZT layers, it is very important to develop a very reliable mathematical model and to use a very accurate computational method to predict accurate dynamic characteristics at very high ultrasonic frequency. In this paper, the axial-bending-shear-lateral contraction coupled differential equations of motion are derived first by the Hamilton's principle with Lagrange multipliers. The smart composite beam is represented by a Timoshenko beam model by adopting the first-order shear deformation theory (FSDT) for the laminated composite base beam. The axial deformation of smart composite beam is improved by taking into account the effects of lateral contraction by adopting the concept of Mindlin-Herrmann rod theory. The spectral element model is then formulated by the variation approach from coupled differential equations of motion transformed into the frequency domain via the discrete Fourier transform. The high accuracy of the present spectral element model is verified by comparing with other solution methods: the finite element model developed in this paper and the commercial FEA package ANSYS. Finally the dynamics and wave characteristics of some example smart composite beams are investigated through the numerical studies.

  10. RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD FOR EFFECTIVE NONLINEAR PROPERTIES OF COMPOSITE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of nonlinear problems are difficult to be managed by the theoretical methods. The present study aims to use the developed method, the random microstructure finite element method, to deal with these nonlinear problems. In this paper, the random microstructure finite element method is used to deal with all three kinds of nonlinear property problems of composite materials. The analyzed results suggest that the influences of the nonlinear phenomena on the effective properties of composite materials are significant and the random microstructure finite element method is an efficient tool to investigate the nonlinear problems.

  11. Low-velocity Impact Damage Analysis of Composite Laminates Using Self-adapting Delamination Element Method

    Institute of Scientific and Technical Information of China (English)

    Wang Lipeng; Yan Ying; Wu Dafang; Wu Hao

    2008-01-01

    On the basis of a 2D 4-node Mindlin shell element method, a novel self-adapting delamination finite element method is presented,which is developed to model the delamination damage of composite laminates. In the method, the sublaminate elements are generated automatically when the delamination damage occurs or extends. Thus, the complex process and state of delamination damage can be simulated practically with high efficiency for both analysis and modeling. Based on the self-adapting delamination method, linear dynamic finite element damage analysis is performed to simulate the low-velocity impact damage process of three types of mixed woven composite laminates. Taking the frictional force among sublaminations during delaminating and the transverse normal stress into account,the analytical results ate consistent with those of the experimental data.

  12. A lowest-order composite finite element exact sequence on pyramids

    Science.gov (United States)

    Ainsworth, Mark; Fu, Guosheng

    2017-09-01

    Composite basis functions for pyramidal elements on the spaces $H^1(\\Omega)$, $H(\\mathrm{curl},\\Omega)$, $H(\\mathrm{div},\\Omega)$ and $L^2(\\Omega)$ are presented. In particular, we construct the lowest-order composite pyramidal elements and show that they respect the de Rham diagram, i.e. we have an exact sequence and satisfy the commuting property. Moreover, the finite elements are fully compatible with the standard finite elements for the lowest-order Raviart-Thomas-N\\'ed\\'elec sequence on tetrahedral and hexahedral elements. That is to say, the new elements have the same degrees of freedom on the shared interface with the neighbouring hexahedral or tetrahedra elements, and the basis functions are conforming in the sense that they maintain the required level of continuity (full, tangential component, normal component, ...) across the interface. Furthermore, we study the approximation properties of the spaces as an initial partition consisting of tetrahedra, hexahedra and pyramid elements is successively subdivided and show that the spaces result in the same (optimal) order of approximation in terms of the mesh size $h$ as one would obtain using purely hexahedral or purely tetrahedral partitions.

  13. Numerical evaluation of bulk material properties of dental composites using two-phase finite element models.

    Science.gov (United States)

    Li, Jianying; Li, Haiyan; Fok, Alex S L; Watts, David C

    2012-09-01

    The aim of this study was to numerically evaluate the effects of filler contents and resin properties on the material properties of dental composites utilizing realistic 3D micromechanical finite element models. 3D micromechanical finite element models of dental composites containing irregular fillers with non-uniform sizes were created based on a large-scale, surrogate mixture fabricated from irregularly shaped stones and casting resin. The surrogate mixture was first scanned with a micro-CT scanner, and the images reassembled to produce a 3D finite element model. Different filler fractions were achieved by adjusting the matrix volume while keeping the fillers unchanged. Polymerization shrinkage, Young's modulus, Poisson's ratio and viscosity of the model composites were predicted using the finite element models, and their dependence on the filler fraction and material properties of the resin matrix were considered. Comparison of the numerical predictions with available experimental data and analytical models from the literature was performed. Increased filler fraction resulted in lower material shrinkage, higher Young's modulus, lower Poisson's ratio and higher viscosity in the composite. Predicted shrinkage and Young's modulus agreed well with the experimental data and analytical predictions. The McGee-McCullough model best fit the shrinkage and Young's modulus predicted by the finite element method. However, a new parameter, used as the exponent of the filler fraction, had to be introduced to the McGee-McCullough model to better match the predicted viscosity and Poisson's ratio with those from the finite element analysis. Realistic micro-structural finite element models were successfully applied to study the effects of filler fraction and matrix properties on a wide range of mechanical properties of dental composites with irregular fillers. The results can be used to direct the design of such materials to achieve the desired mechanical properties. Published by

  14. Heavy metals and trace elements in atmospheric fall-out: Their relationship with topsoil and wheat element composition

    Energy Technology Data Exchange (ETDEWEB)

    Bermudez, Gonzalo M.A., E-mail: gbermudez@com.uncor.edu [Instituto Multidisciplinario de Biologia Vegetal (IMBIV), CONICET (Argentina); Catedra de Quimica General, FCEFyN, Universidad Nacional de Cordoba, Avda. Velez Sarsfield 1611, Ciudad Universitaria (X5016 GCA), Cordoba (Argentina); Jasan, Raquel; Pla, Rita [Tecnicas Analiticas Nucleares, Comision Nacional de Energia Atomica (CAE), Presbitero Gonzalez y Aragon N Degree-Sign 15 (B1802AYA), Ezeiza (Argentina); Pignata, Maria L. [Instituto Multidisciplinario de Biologia Vegetal (IMBIV), CONICET (Argentina); Catedra de Quimica General, FCEFyN, Universidad Nacional de Cordoba, Avda. Velez Sarsfield 1611, Ciudad Universitaria (X5016 GCA), Cordoba (Argentina)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer Metal and trace element deposition rates and concentrations in bulk samples. Black-Right-Pointing-Pointer Anthropogenic vs. natural sources were identified using enrichment factors and PCA. Black-Right-Pointing-Pointer Anthropogenic sources for Ca, Cd, Cu, Fe, Mn, Ni, Pb, Sb, U, Zn and lanthanides. Black-Right-Pointing-Pointer Main sources were a cement plant, chemical-mechanical industries, cities and mining. Black-Right-Pointing-Pointer Metals in wheat grain were predicted by soil and bulk deposition composition. - Abstract: The objectives of this study were to determine the average concentrations and deposition rates of 28 elements in atmospheric bulk deposition and to elucidate associations among topsoil, bulk deposition and wheat element composition. The fluxes of arsenic (As), copper (Cu), lead (Pb) and zinc (Zn) deposition in Cordoba were higher than in other agro-ecosystems, which reflects both natural (geochemistry and topsoil removal) and anthropogenic sources. High lanthanide, uranium (U) and thorium (Th) concentrations revealed the impact of an open cast uranium mine. The highest enrichment factors (EF) were those of Cu, Pb, Zn and nickel (Ni), with calcium (Ca) being the most prominent in the surroundings of a cement plant. Industries and the transport of airborne urban pollutants were the main anthropogenic sources for Ca, Cu, Ni, Pb, Zn, cadmium (Cd), iron (Fe), manganese (Mn) and antimony (Sb). The concentrations of metals in wheat grain were predicted using the topsoil and atmospheric fall-out composition with R{sup 2} = 0.90, with the latter being the best explanatory variable. The present study highlights the potential health hazards of wheat consumption (Environmental Protection Agency) by the assessment of heavy metals in bulk atmospheric deposition.

  15. Light and heavy element isotopic compositions of mainstream SiC grains.

    Energy Technology Data Exchange (ETDEWEB)

    Amari, S.; Clayton, R. N.; Davis, A. M.; Lewis, R. S.; Pellin, M. J.

    1999-02-03

    Although a variety of types of pre-solar SiC grains have been classified by their C, N, and Si isotopic composition, the majority of such grains are so-called mainstream grains and are believed to have come from asymptotic giant branch stars [1]. We have previously reported the Mo isotopic compositions of presolar SiC grains whose C, N, and Si isotopic compositions were not known [2]. Since most presolar SiC grains fall in the mainstream group, we assumed that these grains were mainstream. The excellent match of the Mo isotopic data with expectations for nucleosynthesis in AGB stars was consistent with this identification. In order to better understand the distribution of isotopic compositions in presolar grains, we have begun to measure heavy element isotopic compositions of presolar SiC grains of known C, N and Si isotopic composition.

  16. Structural analysis of composite wind turbine blades nonlinear mechanics and finite element models with material damping

    CERN Document Server

    Chortis, Dimitris I

    2013-01-01

    This book concerns the development of novel finite elements for the structural analysis of composite beams and blades. The introduction of material damping is also an important aspect of composite structures and it is presented here in terms of their static and dynamic behavior. The book thoroughly presents a new shear beam finite element, which entails new blade section mechanics, capable of predicting structural blade coupling due to composite coupling and/or internal section geometry. Theoretical background is further expanded towards the inclusion of nonlinear structural blade models and damping mechanics for composite structures. The models effectively include geometrically nonlinear terms due to large displacements and rotations, improve the modeling accuracy of very large flexible blades, and enable the modeling of rotational stiffening and buckling, as well as, nonlinear structural coupling. Validation simulations on specimen level study the geometric nonlinearities effect on the modal frequencies and...

  17. Structural Performance of Light Weight Multicellular FRP Composite Bridge Deck Using Finite Element Analysis

    Institute of Scientific and Technical Information of China (English)

    Woraphot Prachasaree; Pongsak Sookmanee

    2012-01-01

    Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials,non-corrosiveness and modularization,which should help engineers to obtain more efficient and cost effective structural materials and systems.Currently,FRP composites are becoming more popular in civil engineering applications.The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling,and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations.The relative deflection,equivalent flexural rigidity,failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail.The finite element results showing good correlations with experimental data are presented in this work.

  18. Postmodern landscape architecture: theoretical, compositional characteristics and design elements with the analysis of 25 projects

    Directory of Open Access Journals (Sweden)

    Eplényi Anna

    2015-12-01

    Full Text Available This paper endeavours to highlight three aspects of postmodern landscape design: theoretical basis, composition and design elements. Postmodern theories, philosophy influenced the language of the postmodern landscape architecture and got materialized in the use of narratives, eclecticism, the Rhizome-principle. Postmodern landscape composition can be associated with anti-hierarchy, unusual structures, landforms, and playful moods. Postmodern design elements consist of the strong graphical use of colour and pavements, bizarre water features, unusual structures and buildings, postmodern sculptures and thematic garden details. 25 analysed projects try to capture the essence of postmodernism in landscape architecture as well as to reveal points of intersection within these projects.

  19. Validation of a finite element model of the human metacarpal.

    Science.gov (United States)

    Barker, D S; Netherway, D J; Krishnan, J; Hearn, T C

    2005-03-01

    Implant loosening and mechanical failure of components are frequently reported following metacarpophalangeal (MCP) joint replacement. Studies of the mechanical environment of the MCP implant-bone construct are rare. The objective of this study was to evaluate the predictive ability of a finite element model of the intact second human metacarpal to provide a validated baseline for further mechanical studies. A right index human metacarpal was subjected to torsion and combined axial/bending loading using strain gauge (SG) and 3D finite element (FE) analysis. Four different representations of bone material properties were considered. Regression analyses were performed comparing maximum and minimum principal surface strains taken from the SG and FE models. Regression slopes close to unity and high correlation coefficients were found when the diaphyseal cortical shell was modelled as anisotropic and cancellous bone properties were derived from quantitative computed tomography. The inclusion of anisotropy for cortical bone was strongly influential in producing high model validity whereas variation in methods of assigning stiffness to cancellous bone had only a minor influence. The validated FE model provides a tool for future investigations of current and novel MCP joint prostheses.

  20. EH3 matrix mineralogy with major and trace element composition compared to chondrules

    Science.gov (United States)

    Lehner, S. W.; McDonough, W. F.; NéMeth, P.

    2014-12-01

    We investigated the matrix mineralogy in primitive EH3 chondrites Sahara 97072, ALH 84170, and LAR 06252 with transmission electron microscopy; measured the trace and major element compositions of Sahara 97072 matrix and ferromagnesian chondrules with laser-ablation, inductively coupled, plasma mass spectrometry (LA-ICPMS); and analyzed the bulk composition of Sahara 97072 with LA-ICPMS, solution ICPMS, and inductively coupled plasma atomic emission spectroscopy. The fine-grained matrix of EH3 chondrites is unlike that in other chondrite groups, consisting primarily of enstatite, cristobalite, troilite, and kamacite with a notable absence of olivine. Matrix and pyroxene-rich chondrule compositions differ from one another and are distinct from the bulk meteorite. Refractory lithophile elements are enriched by a factor of 1.5-3 in chondrules relative to matrix, whereas the matrix is enriched in moderately volatile elements. The compositional relation between the chondrules and matrix is reminiscent of the difference between EH3 pyroxene-rich chondrules and EH3 Si-rich, highly sulfidized chondrules. Similar refractory element ratios between the matrix and the pyroxene-rich chondrules suggest the fine-grained material primarily consists of the shattered, sulfidized remains of the formerly pyroxene-rich chondrules with the minor addition of metal clasts. The matrix, chondrule, and metal-sulfide nodule compositions are probably complementary, suggesting all the components of the EH3 chondrites came from the same nebular reservoir.

  1. Mechanical tests, static and modal finite element analysis for MWCNT composite materials

    Directory of Open Access Journals (Sweden)

    Daniela BARAN

    2015-03-01

    Full Text Available The main purpose of this paper is to develop some numerical experiences based on mechanical tests performed on MWCNT (Multi-wall carbon nanotubes composites created in our Material compartment using finite element commercial codes (here NASTRAN. The results of numerical simulations are consistent with the laboratory tests and encourage us to continue to improve the models using NASTRAN capabilities in order to obtain a realistic simulation of aeronautical structures made of such composites, considering their special properties.

  2. Thermal Stress Analysis of Laminated Composite Plates using Shear Flexible Element

    Directory of Open Access Journals (Sweden)

    M. Ganapathi

    1996-01-01

    Full Text Available Using degree Centigrade shear flexible QUAD-9 plate element, stresses and deflections in composite laminated plates due to thermal loads analysed. A formulation based on first order shear deformation theory has been employed for the analysis. The effects of various parameters, such as ply-angle, number of layers, thickness and aspect ratios on stresses and deflections are brought out. The present formulation is being extended for studying composite shell structures.

  3. Finite element model updating of natural fibre reinforced composite structure in structural dynamics

    Directory of Open Access Journals (Sweden)

    Sani M.S.M.

    2016-01-01

    Full Text Available Model updating is a process of making adjustment of certain parameters of finite element model in order to reduce discrepancy between analytical predictions of finite element (FE and experimental results. Finite element model updating is considered as an important field of study as practical application of finite element method often shows discrepancy to the test result. The aim of this research is to perform model updating procedure on a composite structure as well as trying improving the presumed geometrical and material properties of tested composite structure in finite element prediction. The composite structure concerned in this study is a plate of reinforced kenaf fiber with epoxy. Modal properties (natural frequency, mode shapes, and damping ratio of the kenaf fiber structure will be determined using both experimental modal analysis (EMA and finite element analysis (FEA. In EMA, modal testing will be carried out using impact hammer test while normal mode analysis using FEA will be carried out using MSC. Nastran/Patran software. Correlation of the data will be carried out before optimizing the data from FEA. Several parameters will be considered and selected for the model updating procedure.

  4. The elemental composition of the Sun III. The neutron capture elements Cu to Th

    CERN Document Server

    Grevesse, Nicolas; Asplund, Martin; Sauval, A Jacques

    2014-01-01

    We re-evaluate the abundances of the elements in the Sun from copper ($Z=29$) to thorium ($Z=90$). Our results are mostly based on neutral and singly-ionised lines in the solar spectrum. We use the latest 3D hydrodynamic solar model atmosphere, and in a few cases also correct for departures from local thermodynamic equilibrium (NLTE). In order to minimise statistical and systematic uncertainties, we make stringent line selections, employ the highest-quality observational data and carefully assess oscillator strengths, hyperfine constants and isotopic separations available in the literature, for every line included in our analysis. Our results are typically in good agreement with the abundances in the most pristine meteorites, but there are some interesting exceptions. This analysis constitutes both a full exposition and a slight update of the relevant parts of the preliminary results we presented in Asplund, Grevesse, Sauval & Scott (arXiv:0909.0948), including full line lists and details of all input dat...

  5. Numerical Homogenization of Protective Ceramic Composite Layers using the Hybrid Finite-Discrete Element Methods

    Directory of Open Access Journals (Sweden)

    Zainorizuan Mohd Jaini

    2013-12-01

    Full Text Available Innovative technologies have resulted in more effective ceramic composite as high rate loading-resistance and protective layer. The ceramic composite layer consists of ceramic frontal plate that bonded by softer-strong reinforced polymer network, consequently gains the heterogeneous condition. These materials serve specific purposes of defeating high rate loading and maintaining the structural integrity of the layer. Further due to the lack of a constituent material and tedious problem in heterogonous material modelling, a numerical homogenization is employed to analyse the isotropic material properties of ceramic composite layer in homogenous manner. The objective of this study is to derive a constitutive law of the ceramic composite using the multi-scale analysis. Two-dimensional symmetric macrostructure of the ceramic composite was numerically modelled using the hybrid finite-discrete element method to investigate the effective material properties and strength profile. The macrostructure was modelled as brittle material with nonlinear material properties. The finite element method is incorporated with a Rankine-Rotating Crack approach and discrete element to model the fracture onset. The prescribed uniaxial and biaxial loadings were imposed along the free boundaries to create different deformations. Due to crack initiation on the macrostructure, the averaged stresses were calculated to plot the stress-strain curves and the effective yield stress surface. From the multi-scale analysis, the rate-dependency of Mohr-Coulomb constitutive law was derived for the ceramic composite layer.

  6. Shear-flexible finite-element models of laminated composite plates and shells

    Science.gov (United States)

    Noor, A. K.; Mathers, M. D.

    1975-01-01

    Several finite-element models are applied to the linear static, stability, and vibration analysis of laminated composite plates and shells. The study is based on linear shallow-shell theory, with the effects of shear deformation, anisotropic material behavior, and bending-extensional coupling included. Both stiffness (displacement) and mixed finite-element models are considered. Discussion is focused on the effects of shear deformation and anisotropic material behavior on the accuracy and convergence of different finite-element models. Numerical studies are presented which show the effects of increasing the order of the approximating polynomials, adding internal degrees of freedom, and using derivatives of generalized displacements as nodal parameters.

  7. Three-Dimensional Effects in the Plate Element Analysis of Stitched Textile Composites

    Science.gov (United States)

    Glaessgen, E. H.; Raju, I. S.

    2000-01-01

    Three-dimensional effects related to the analysis of stitched textile composites are discussed. The method of calculation is based on the virtual crack closure technique (VCCT), and models that model the upper and lower surface of the delamination or debond with two-dimensional (2D) plate elements rather than three-dimensional (3D) solid elements. The major advantages of the plate element modeling technique are a smaller model size and simpler geometric modeling. Details of the modeling of the laminated plate and the stitching are discussed.

  8. Cluster analysis on the bulk elemental compositions of Antarctic stony meteorites

    Science.gov (United States)

    Miyamoto, Hideaki; Niihara, Takafumi; Kuritani, Takeshi; Hong, Peng K.; Dohm, James M.; Sugita, Seiji

    2016-05-01

    Remote sensing observations by recent successful missions to small bodies have revealed the difficulty in classifying the materials which cover their surfaces into a conventional classification of meteorites. Although reflectance spectroscopy is a powerful tool for this purpose, it is influenced by many factors, such as space weathering, lighting conditions, and surface physical conditions (e.g., particle size and style of mixing). Thus, complementary information, such as elemental compositions, which can be obtained by X-ray fluorescence (XRF) and gamma-ray spectrometers (GRS), have been considered very important. However, classifying planetary materials solely based on elemental compositions has not been investigated extensively. In this study, we perform principal component and cluster analyses on 12 major and minor elements of the bulk compositions of 500 meteorites reported in the National Institute of Polar Research (NIPR), Japan database. Our unique approach, which includes using hierarchical cluster analysis, indicates that meteorites can be classified into about 10 groups purely by their bulk elemental compositions. We suggest that Si, Fe, Mg, Ca, and Na are the optimal set of elements, as this set has been used successfully to classify meteorites of the NIPR database with more than 94% accuracy. Principal components analysis indicates that elemental compositions of meteorites form eight clusters in the three-dimensional space of the components. The three major principal components (PC1, PC2, and PC3) are interpreted as (1) degree of differentiations of the source body (i.e., primitive versus differentiated), (2) degree of thermal effects, and (3) degree of chemical fractionation, respectively.

  9. Elemental composition in surface snow from the ultra-high elevation area of Mt. Qomolangma (Everest)

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A total of 14 surface snow (0-10 cm) samples were collected along the climbing route (6500-8844 m a.s.l.) on the northern slope of Mt. Qomolangma in May, 2005. Analysis of elemental concentrations in these samples showed that there are no clear trends for element variations with elevation due to redistribution of surface snow by strong winds during spring. In addition, local crustal aerosol inputs also have an influence on elemental composition of surface snow. Comparison between elemental concentration datasets of 2005 and 1997 indicated that data from 2005 were of higher quality. Elemental concentrations (especially for heavy metals) at Mt. Qomolangma are comparable with polar sites, and far lower than large cities. This indicates that anthropogenic activities and heavy metal pollution have little effect on the Mt. Qomolangma atmospheric environment, which can be representative of the background atmospheric environment.

  10. ESL Based Cylindrical Shell Elements with Hierarchical Shape Functions for Laminated Composite Shells

    Directory of Open Access Journals (Sweden)

    Jae S. Ahn

    2015-01-01

    Full Text Available We introduce higher-order cylindrical shell element based on ESL (equivalent single-layer theory for the analysis of laminated composite shells. The proposed elements are formulated by the dimensional reduction technique from three-dimensional solid to two-dimensional cylindrical surface with plane stress assumption. It allows the first-order shear deformation and considers anisotropic materials due to fiber orientation. The element displacement approximation is established by the integrals of Legendre polynomials with hierarchical concept to ensure the C0-continuity at the interface between adjacent elements as well as C1-continuity at the interface between adjacent layers. For geometry mapping, cylindrical coordinate is adopted to implement the exact mapping of curved shell configuration with a constant curvature with respect to any direction in the plane. The verification and characteristics of the proposed element are investigated through the analyses of three cylindrical shell problems with different shapes, loadings, and boundary conditions.

  11. Finite element analysis of WC-Al2O3 composites

    Science.gov (United States)

    Patel, Satyanarayan; Vaish, Rahul

    2014-02-01

    Object oriented finite element analysis (OOF2) is used to estimate the thermal and mechanical properties of WC-Al2O3 composites. In the present work, five compositions of 10%, 20%, 30%, 40% and 50% Al2O3 (by volume) are studied. Young's modulus, thermal conductivity and thermal expansion coefficient are estimated using OOF2 and compared with other known analytical methods. Stress and strain contours are plotted to study the thermal and mechanical behavior of composites. It is found that the stresses are largely concentrated at the interfaces of the WC-Al2O3 phases.

  12. The Nakhla parent melt: REE partition coefficients and clues to major element composition

    Science.gov (United States)

    Mckay, G.; Le, L.; Wagstaff, J.

    1993-01-01

    Nakhla is one of the SNC meteorites, generally believed to be of Martian origin. It is a medium-grained augite-olivine cumulate with a variolitic groundmass of sodic plagioclase, alkali feldspar, and Fe-rich pyroxenes and olivine. One of the major tasks in deciphering Nakhla's petrogenesis is determining the composition of its parent melt. Gaining an understanding of the composition and petrogenesis of this parent melt may help unravel Nakhla's relationship to the other SNCs, and provide clues to Martian petrogenesis in general. Our experimental partitioning studies provide new information that helps constrain both the major and trace element composition of the Nakhla parent melt.

  13. Lentivirus vectors using human and simian immunodeficiency virus elements.

    Science.gov (United States)

    White, S M; Renda, M; Nam, N Y; Klimatcheva, E; Zhu, Y; Fisk, J; Halterman, M; Rimel, B J; Federoff, H; Pandya, S; Rosenblatt, J D; Planelles, V

    1999-04-01

    Lentivirus vectors based on human immunodeficiency virus (HIV) type 1 (HIV-1) constitute a recent development in the field of gene therapy. A key property of HIV-1-derived vectors is their ability to infect nondividing cells. Although high-titer HIV-1-derived vectors have been produced, concerns regarding safety still exist. Safety concerns arise mainly from the possibility of recombination between transfer and packaging vectors, which may give rise to replication-competent viruses with pathogenic potential. We describe a novel lentivirus vector which is based on HIV, simian immunodeficiency virus (SIV), and vesicular stomatitis virus (VSV) and which we refer to as HIV/SIVpack/G. In this system, an HIV-1-derived genome is encapsidated by SIVmac core particles. These core particles are pseudotyped with VSV glycoprotein G. Because the nucleotide homology between HIV-1 and SIVmac is low, the likelihood of recombination between vector elements should be reduced. In addition, the packaging construct (SIVpack) for this lentivirus system was derived from SIVmac1A11, a nonvirulent SIV strain. Thus, the potential for pathogenicity with this vector system is minimal. The transduction ability of HIV/SIVpack/G was demonstrated with immortalized human lymphocytes, human primary macrophages, human bone marrow-derived CD34(+) cells, and primary mouse neurons. To our knowledge, these experiments constitute the first demonstration that the HIV-1-derived genome can be packaged by an SIVmac capsid. We demonstrate that the lentivirus vector described here recapitulates the biological properties of HIV-1-derived vectors, although with increased potential for safety in humans.

  14. Neglecting human ecology: The common element of global health failures

    Science.gov (United States)

    Hanley, Matthew

    2016-01-01

    Attempts to control malaria, AIDS, and maternal mortality in Africa have been woefully inadequate. This has involved adopting an almost exclusively technical preventive approach in the context of AIDS even though emphasizing human behavior holds the most promise. But on the other hand, it has also involved abandoning highly effective technical measures, as in the case of malaria. This suggests that the failure, at root, is anthropological in nature. The common element, it is argued here, is the failure to place the human ecology resolutely above destructive ideologies. Sound public-health approaches have been spurned in favor of predetermined preventive approaches in the service of ideological aims rather than of man and the common good. This article examines the ideological forces that have ultimately driven global health policy, and proposes that a more humane anthropology would be beneficial. Lay Summary: The scourges of malaria, AIDS, and maternal mortality have persisted in Africa, even though sensible and available means of addressing these epidemics, when stressed, have met with success. The reluctance to consistently emphasize the soundest public-health approaches—whether technical or behavioral in nature—indicate that global health policy has to a large extent been improperly concerned with advancing ideological agendas. The challenge we face today is not primarily technical but philosophical; the healing professions would perform a service by cultivating a higher view of man and an appreciation for objective moral truths that protect him. PMID:27833184

  15. Earth's moderately volatile element composition may not be chondritic: Evidence from In, Cd and Zn

    Science.gov (United States)

    Wang, Zaicong; Laurenz, Vera; Petitgirard, Sylvain; Becker, Harry

    2016-02-01

    Current models assume that siderophile volatile elements (SVE) are depleted in bulk Earth to the same extent as lithophile elements of similar volatility. The observed additional depletion of many SVE relative to lithophile elements in the bulk silicate Earth (BSE) is ascribed to partitioning of SVE into Earth's core. However, the assumption of similar volatility of moderately volatile elements during Earth formation processes as in solar gas is quite uncertain. Here, these assumptions will be tested by assessing abundances and ratios of indium and cadmium in the BSE using new data on mantle rocks, and the application of high- and low-pressure-temperature metal-silicate partitioning data. New bulk rock abundance data of In and Cd obtained on bulk rocks of peridotite tectonites and xenoliths by isotope dilution refine previous results inferred from basalts and in-situ analyses of silicate minerals in peridotite xenoliths. The CI chondrite-normalized abundance of In in the BSE is similar to zinc and is 3-4 times higher than Cd. New and published low- and high-P-T metal-silicate partitioning data indicate that, during core formation at a range of conditions, In is always more siderophile than Zn and Cd. Adding the fraction of these elements in Earth's core to the BSE results in bulk Earth compositions that yield higher CI chondrite normalized abundances of In in the bulk Earth compared to Zn and Cd. Because In is more volatile than Zn and Cd in gas of solar composition, suprachondritic In/Zn and In/Cd in the bulk Earth suggest that during formation of Earth or its building materials, the volatilities of these elements and perhaps other volatile elements likely have changed significantly (i.e. In became less volatile). The results also suggest that known carbonaceous chondrites likely did not deliver the main volatile element-rich fraction of the Earth. Various arguments suggest that the loss of moderately volatile elements during planetary accretion should be limited

  16. Free vibration of composite skewed cylindrical shell panel by finite element method

    Science.gov (United States)

    Haldar, Salil

    2008-03-01

    In this paper a composite triangular shallow shell element has been used for free vibration analysis of laminated composite skewed cylindrical shell panels. In the present element first-order shear deformation theory has been incorporated by taking transverse displacement and bending rotations as independent field variables. The interpolation function used to approximate transverse displacement is one order higher than for bending rotations. This has made the element free from locking in shear. Two types of mass lumping schemes have been recommended. In one of the mass lumping scheme the effect of rotary inertia has been incorporated in the element formulations. Free vibration of skewed composite cylindrical shell panels having different thickness to radius ratios ( h/R=0.01-0.2), length to radius ratios ( L/R), number of layers and fiber orientation angles have been analyzed following the shallow shell method. The results for few examples obtained in the present analysis have compared with the published results. Some new results of composite skewed cylindrical shell panels have been presented which are expected to be useful to future research in this direction.

  17. Finite Element Analysis of Composite Deck Slab Using Perfobond Rib as Shear Connection System under Vertical Loading

    Directory of Open Access Journals (Sweden)

    Omid Monshi Toussi

    2016-01-01

    Full Text Available Nowadays, the composite decks are very common to use in composite or steel construction. In this case of study the composite slabs have been investigated numerically by Finite Element Method (FEM. Five composite slabs were analyzed using finite element software LUSAS. The deflection of each model were obtained and compared with experimental test. Results showed a good agreement with the experimental data and indicate that the perfobond rib is appropriate shear connector for the bridges decks.

  18. Transient response of isotropic, orthotropic and anisotropic composite-sandwich shells with the superparametric element

    Science.gov (United States)

    Mallikarjuna; Kant, T.; Fafard, M.

    1992-09-01

    The first-order Reissner-Mindlin shear deformation theory is employed to investigate the transient response of isotropic, layered orthotropic and anisotropic composite and sandwich shells. The eight-noded Serendipity and nine-noded Lagrangian quadrilateral superparametric shell elements are used. Numerical convergence and stability of the elements are established using an explicit central difference technique with a special mass matrix diagonalization scheme. The effects of transverse shear modulii of stiff layers, length/thickness and radius/length ratios, time step, finite element mesh, orientation of fibers and degree of orthotropy on the transient response of shells are studied. The variety of results presented here, based on realistic material properties of more commonly used advanced laminated composite shells, should serve as references for future investigations.

  19. Detection of Elemental Composition of Lubricating Grease Using Laser Induced Breakdown Spectroscopy

    Directory of Open Access Journals (Sweden)

    Cherry Dhiman

    2014-12-01

    Full Text Available The elemental composition of lubricating soft grease used in rail engines are studied using laser induced breakdown spectroscopy (LIBS technique. LIBS spectra of fresh, partially used and fully used grease samples are recorded using time-gated ICCD spectrometer for verification of compositional degradation of the used grease. LIBS spectra of grease samples are analyzed by comparing with emission spectra of elements published by NIST standard database. Many spectral lines of impurity elements like Fe, Cu, Ba, Mg, Mn, Ni, S, Zn, Si, Pb, Ti, Ca and Al present in the grease in ppm or ppb level in trace level concentrations are observed in excess in the used grease mainly due to wear and tear. On the other hand in fresh grease, spectral lines of Ca, Al and Na are observed predominantly.

  20. Elemental stoichiometry and compositions of weevil larvae and two acorn hosts under natural phosphorus variation.

    Science.gov (United States)

    Ji, Huawei; Du, Baoming; Liu, Chunjiang

    2017-04-05

    To understand how different trophic organisms in a parasite food chain adapt to the differences in soil nutrient conditions, we investigated stoichiometric variation and homeostasis of multiple elements in two acorn trees, Quercus variabilis and Quercus acutissima, and their parasite weevil larvae (Curculio davidi Fairmaire) at phosphorus (P)-deficient and P-rich sites in subtropical China where P-rich ores are scattered among dominant P-deficient soils. Results showed that elemental stoichiometry and compositions of both acorns and weevil larvae differed significantly between P-deficient and P-rich sites (p stoichiometry and compositions (p stoichiometry and composition and physiological regulations of nutritional needs in organisms and provide possible stoichiometric responses of both plants and animals to P loading, a worldwide issue from excess release of P into the environment.

  1. The Use of Sprint Interface Element Delamination Simulation of Sandwich Composite Beam

    Science.gov (United States)

    Xu, Geng; Yan, Renjun

    2016-12-01

    Sandwich composite beams have been more and more used in various industries because of their excellent mechanical properties. However, the mismatched performance between face sheet and foam core always lead to such as cracks and damages in the core or face/core interface during the processes of manufacturing or service. Delamination damage at the adhesive interface is the most dangerous and could be one main source that the mechanical capability of the structure is serous degenerated. In this paper, a simple and natural model to evaluate the stiffness of the spring interface elements, which is based on the physics and the geometry of the adhesive layers, is proposed. In order to validate the model, cantilever beam bending test were conducted for marine sandwich composite I-beam. A good comparison has been found between predictions and experimental results, and results indicate that the spring interface element can provide an efficient model for the delamination simulation of sandwich composite structures.

  2. Finite-Element Analysis of Jute- and Coir-Fiber-Reinforced Hybrid Composite Multipanel Plates

    Science.gov (United States)

    Nirbhay, M.; Misra, R. K.; Dixit, A.

    2015-09-01

    Natural-fiber-reinforced polymer composite materials are rapidly gaining interest worldwide both in terms of research and industrial applications. The present work includes the characterization and modeling of jute- and coir-fiber-reinforced hybrid composite materials. The mechanical behavior of a two-panel plate and a sixpanel box structure is analyzed under various loading regimes by using the finite-element software ABAQUS®. Exhaustive parametric studies are also performed to obtain a clear insight into the relationships between various parameters and deflections of the panels and stress distributions in them. Deflections of both the structures are compared and found to be in good agreement with published results. To determine the mechanical behavior of natural-fiber-reinforced composite panels, a finite-element analysis is performed.

  3. Finite Element Modeling of Thermal Cycling Induced Microcracking in Carbon/Epoxy Triaxial Braided Composites

    Science.gov (United States)

    Zhang, Chao; Binienda, Wieslaw K.; Morscher, Gregory; Martin, Richard E.

    2012-01-01

    The microcrack distribution and mass change in PR520/T700s and 3502/T700s carbon/epoxy braided composites exposed to thermal cycling was evaluated experimentally. Acoustic emission was utilized to record the crack initiation and propagation under cyclic thermal loading between -55 C and 120 C. Transverse microcrack morphology was investigated using X-ray Computed Tomography. Different performance of two kinds of composites was discovered and analyzed. Based on the observations of microcrack formation, a meso-mechanical finite element model was developed to obtain the resultant mechanical properties. The simulation results exhibited a decrease in strength and stiffness with increasing crack density. Strength and stiffness reduction versus crack densities in different orientations were compared. The changes of global mechanical behavior in both axial and transverse loading conditions were studied. Keywords: Thermal cycles; Microcrack; Finite Element Model; Braided Composite

  4. Constitutive Behavior and Finite Element Analysis of FRP Composite and Concrete Members

    Directory of Open Access Journals (Sweden)

    Ki Yong Ann

    2013-09-01

    Full Text Available The present study concerns compressive and flexural constitutive models incorporated into an isoparametric beam finite element scheme for fiber reinforced polymer (FRP and concrete composites, using their multi-axial constitutive behavior. The constitutive behavior of concrete was treated in triaxial stress states as an orthotropic hypoelasticity-based formulation to determine the confinement effect of concrete from a three-dimensional failure surface in triaxial stress states. The constitutive behavior of the FRP composite was formulated from the two-dimensional classical lamination theory. To predict the flexural behavior of circular cross-section with FRP sheet and concrete composite, a layered discretization of cross-sections was incorporated into nonlinear isoparametric beam finite elements. The predicted constitutive behavior was validated by a comparison to available experimental results in the compressive and flexural beam loading test.

  5. Epigenetic regulation of transposable element derived human gene promoters.

    Science.gov (United States)

    Huda, Ahsan; Bowen, Nathan J; Conley, Andrew B; Jordan, I King

    2011-04-01

    It was previously thought that epigenetic histone modifications of mammalian transposable elements (TEs) serve primarily to defend the genome against deleterious effects associated with their activity. However, we recently showed that, genome-wide, human TEs can also be epigenetically modified in a manner consistent with their ability to regulate host genes. Here, we explore the ability of TE sequences to epigenetically regulate individual human genes by focusing on the histone modifications of promoter sequences derived from TEs. We found 1520 human genes that initiate transcription from within TE-derived promoter sequences. We evaluated the distributions of eight histone modifications across these TE-promoters, within and between the GM12878 and K562 cell lines, and related their modification status with the cell-type specific expression patterns of the genes that they regulate. TE-derived promoters are significantly enriched for active histone modifications, and depleted for repressive modifications, relative to the genomic background. Active histone modifications of TE-promoters peak at transcription start sites and are positively correlated with increasing expression within cell lines. Furthermore, differential modification of TE-derived promoters between cell lines is significantly correlated with differential gene expression. LTR-retrotransposon derived promoters in particular play a prominent role in mediating cell-type specific gene regulation, and a number of these LTR-promoter genes are implicated in lineage-specific cellular functions. The regulation of human genes mediated by histone modifications targeted to TE-derived promoters is consistent with the ability of TEs to contribute to the epigenomic landscape in a way that provides functional utility to the host genome.

  6. The Compositions of Six Chinese Ordinary Chondrites and Element Distributions in Their Different Phases

    Institute of Scientific and Technical Information of China (English)

    陈永亨; ERNSTPERNICKA; 等

    1992-01-01

    Six Chinese ordinary chondrites (four of them have fallen in recent years and the trace element abundances have not yet been reported for the other two) were examined.The contents of 21 elements (Na,Cr,Mn,Sc,Se,Zn,Br,Ni,Fe,Co,Ir,Cu,Ga,As,Au,Sb,Os,W,Re,Pt,and Ru)in the magnetic fractions and 20 elements (Na,K,Ca,Sc,Cr,Mn,Fe,Co,Ni,Zn,Se,Br,La,Sm,Eu,Yb,Lu,Ir,Au,and As) in the non-magnetic fractions were de-termined by INAA. The results indicate that the 5 H-group chondrites show almost no difference in composition,but they are different from the Zhaodong L-group chondrite in elemental abundance.As a normalized element(relative to CI),the concentrations of Ga in the magnetic fractions can be used to classify ordinary chondrites(H-,L- and LL-group).The bulk composition and modal weight of each component calculated from element concentrations in different phases are in good agreement with the bulk rock analyses presented in the literature.

  7. Magnetic susceptibility and element composition mangrove sediments in Malang, East Java

    Science.gov (United States)

    Azzahro, Rosyida; Zulaikah, Siti; Diantoro, Markus; Budi, Pranitha Septiana

    2017-07-01

    Mangrove sediment has a unique environmental absorption characteristics, as it has two sources of sediment which are from allocthonous sediment and authochtonous sediment. In this research, the mangrove sediment samples are taken from Clungup Mangrove Conservation in Malang, East Java, Indonesia. The samples are taken from four spots around the mouth of the river, and four spots around mangrove conservation. Those samples are analyzed based on the magnetic characteristics and the element composition to reveal the magnetic properties and element composition so in the future they can be used as indicators to trace the source of magnetic minerals that are precipitated in the mangrove ecosystem. The magnetic susceptibility value based on mass for mangrove sediment around the river area h as the range of (38,8-2130)×10-8m3kg-1, while for the conservation area has the range of (0,97-122,5)×10-8m3kg-1. Based on XRF analysis, the mangrove sediment both from the river area and mangrove conservation area has a non-metallic element S, Br, metallic element Ca, Si, Al, K, Ti, Sr, and heavy metallic element Fe, Ni, Cu, Cr, Zn, Zr, Mn, and V, with the highest concentration of Fe element followed by Ca, Al, Si, and Ti.

  8. Finite Element Studies on Free Vibration of Laminated Composite Cylindrical Skew Panels

    Directory of Open Access Journals (Sweden)

    Srinivasa Chikkol Venkateshappa

    2014-01-01

    Full Text Available This paper presents the finite element studies made on free vibration of isotropic and laminated composite cylindrical skew panels. A finite element analysis is performed using CQUAD4 and CQUAD8 elements of MSC/NASTRAN software. The effects of the panel angle, skew angle, aspect ratio, and length-to-thickness-ratio on fundamental natural frequency of vibration of isotropic cylindrical skew panels are studied. The effects of additional parameters such as fiber orientation angle, numbers of layers (keeping total thickness constant, and laminate stacking sequence on the fundamental frequency of vibration of antisymmetric composite laminates have also been studied. During validation and convergence study, it is found that the CQUAD8 element yields more accurate results than the CQUAD4 element. Hence the CQUAD8 element has been employed for the remaining part of the investigation. The fundamental frequency is found to increase with the panel angle and skew angle. The variation of the fundamental frequency with the number of layers is not appreciable when the number of layers is greater than about 6. It is also seen that the boundary conditions have significant influence on the fundamental frequency.

  9. Multi-element composition of soils of seasonal wetlands across North Dakota, USA.

    Science.gov (United States)

    Yellick, A H; Jacob, D L; DeKeyser, E S; Hargiss, C L M; Meyers, L M; Ell, M; Kissoon-Charles, L T; Otte, M L

    2016-01-01

    The main goal of this study was to assess if the soils of wetlands of different condition varied in terms of element composition. The rationale was that compared to wetlands of good condition, wetlands of poor condition-which in the region have typically been disturbed by agricultural activities, are lower in biodiversity and have fewer native species-would have been altered in their physical and chemical soil characteristics. This in turn would have altered the element composition of the soils. The concentrations of about 50 elements in the topsoil of 43 seasonal wetlands of varying condition, as measured by plant community based assessments, across North Dakota were determined. Organic matter content of the soils increased as condition increased, and it was the most important variable explaining 40 % of variation in the concentrations of elements. This can be partly explained by binding of elements to organic matter (S, Se) and for most other elements (that bind mostly to the inorganic fraction) by displacement by organic matter. The biogeochemistry of S is further implicated in the distribution of Ca, most likely via formation of insoluble gypsum (calcium sulfate).

  10. Detection of Fingerprints Based on Elemental Composition Using Micro-X-Ray Fluorescence.

    Energy Technology Data Exchange (ETDEWEB)

    Worley, C. G. (Christopher G.); Wiltshire, S. (Sara); Miller, T. C. (Thomasin C.); Havrilla, G. J. (George J.); Majidi, V. (Vahid)

    2005-01-01

    A method was developed to detect fingerprints using a technique known as micro-X-ray fluorescence. The traditional method of detecting fingerprints involves treating the sample with certain powders, liquids, or vapors to add color to the fingerprint so that it can be easily seen and photographed for forensic purposes. This is known as contrast enhancement, and a multitude of chemical processing methods have been developed in the past century to render fingerprints visible. However, fingerprints present on certain substances such as fibrous papers and textiles, wood, leather, plastic, adhesives, and human skin can sometimes be difficult to detect by contrast enhancement. Children's fingerprints are also difficult to detect due to the absence of sebum on their skin, and detection of prints left on certain colored backgrounds can sometimes be problematic. Micro-X-ray fluorescence (MXRF) was studied here as a method to detect fingerprints based on chemical elements present in fingerprint residue. For example, salts such as sodium chloride and potassium chloride excreted in sweat are sometimes present in detectable quantities in fingerprints. We demonstrated that MXRF can be used to detect this sodium, potassium, and chlorine from such salts. Furthermore, using MXRF, each of these elements (and many other elements if present) can be detected as a function of location on a surface, so we were able to 'see' a fingerprint because these salts are deposited mainly along the patterns present in a fingerprint (traditionally called friction ridges in forensic science). MXRF is not a panacea for detecting all fingerprints; some prints will not contain enough detectable material to be 'seen'; however, determining an effective means of coloring a fingerprint with traditional contrast enhancement methods can sometimes be an arduous process with limited success. Thus, MXRF offers a possible alternative for detecting fingerprints, and it does not require any

  11. Multi-element Composition of Terricolous Lichens in the Northwest European Russia

    Science.gov (United States)

    Shevchenko, V. P.; Pokrovsky, O. S.; Vasyukova, E. V.; Savvichev, A. S.; Zamber, N. S.

    2008-12-01

    Lichens (fungi living with an alga or cyanobacterium) absorb substances, including trace elements through dry and wet deposition, often to very high concentrations, and have been widely used as biomonitors. We studied multi-element composition of terricolous lichens (mostly of genera Cladonia and Cetraria) collected in 2004-2006 in Kola Peninsula, Karelia and Arkhangelsk Region of NW Russia. 31 samples were analyzed. The unwashed lichen samples were air dried and homogenised to a fine powder in an agate crusher, in order to exclude any contamination of trace metals. Samples were treated in a four-step chemical digestion procedure (full dissolution via acid attack). Major element concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES), and trace element concentrations by inductively coupled plasma-mass spectrometry (ICP-MS, Agilent 7500). An enrichment factor (EF) was calculated for each element (X) relative to the composition of earth's crust: EF = ((X/Al) in lichen) / ((X/Al) in the earth's crust). Al was used as a crustal indicator. In most samples contents of Ti, V, Cr, Mn, Fe, Co, rare earth elements (REEs), Th, U are at the background level and their EFs are less than 10. These low EF values indicated that, relative to average values for crustal rocks, there was no enrichment of these elements in the lichen concerned. For some elements (Se, Cd, Zn, Sb, Pb, As, Ni, Cu) consistently higher EF values were obtained. These higher values were interpreted in terms of sources of both anthropogenic and natural sources other than crustal rock and (or) soil. For instance, these elements could be derived by long-range atmospheric transport. Highest concentrations of Cu, Ni, Pb in lichens and EF by these elements were registered in Lovozersky Tundry (Kola Peninsula) and in Paanayarvi area (NW Karelia). Lichens here are polluted by Monchegorsk and Nickel Cu-Ni smelters. In the vicinity of Kostomukshsky Ore-dressing Mill lichens

  12. Customized Finite Element Modelling of the Human Cornea.

    Directory of Open Access Journals (Sweden)

    Irene Simonini

    Full Text Available To construct patient-specific solid models of human cornea from ocular topographer data, to increase the accuracy of the biomechanical and optical estimate of the changes in refractive power and stress caused by photorefractive keratectomy (PRK.Corneal elevation maps of five human eyes were taken with a rotating Scheimpflug camera combined with a Placido disk before and after refractive surgery. Patient-specific solid models were created and discretized in finite elements to estimate the corneal strain and stress fields in preoperative and postoperative configurations and derive the refractive parameters of the cornea.Patient-specific geometrical models of the cornea allow for the creation of personalized refractive maps at different levels of IOP. Thinned postoperative corneas show a higher stress gradient across the thickness and higher sensitivity of all geometrical and refractive parameters to the fluctuation of the IOP.Patient-specific numerical models of the cornea can provide accurate quantitative information on the refractive properties of the cornea under different levels of IOP and describe the change of the stress state of the cornea due to refractive surgery (PRK. Patient-specific models can be used as indicators of feasibility before performing the surgery.

  13. Depletions of Elements from the Gas Phase: A Guide on Dust Compositions

    CERN Document Server

    Jenkins, Edward B

    2014-01-01

    Ultraviolet spectra of stars recorded by orbiting observatories since the 1970's have revealed absorption features produced by atoms in their favored ionization stages in the neutral ISM of our Galaxy. Most elements show abundances relative to hydrogen that are below their values in stars, indicating their removal by condensation into solid form. The relative amounts of these depletions vary from one location to the next, and different elements show varying degrees of depletion. In a study of abundances along 243 different sight lines reported in more than 100 papers, Jenkins (2009) characterized the systematic patterns for the depletions of 17 different elements, and these results in turn were used to help us understand the compositions of dust grains. Since the conclusions are based on differential depletions along different sightlines, they are insensitive to errors in the adopted values for the total element abundances. Some of the more remarkable conclusions to emerge from this study are that (1) oxygen ...

  14. Finite element implementation and numerical issues of strain gradient plasticity with application to metal matrix composites

    DEFF Research Database (Denmark)

    Frederiksson, Per; Gudmundson, Peter; Mikkelsen, Lars Pilgaard

    2009-01-01

    A framework of finite element equations for strain gradient plasticity is presented. The theoretical framework requires plastic strain degrees of freedom in addition to displacements and a plane strain version is implemented into a commercial finite element code. A couple of different elements...... of quadrilateral type are examined and a few numerical issues are addressed related to these elements as well as to strain gradient plasticity theories in general. Numerical results are presented for an idealized cell model of a metal matrix composite under shear loading. It is shown that strengthening due...... to fiber size is captured but strengthening due to fiber shape is not. A few modelling aspects of this problem are discussed as well. An analytic solution is also presented which illustrates similarities to other theories....

  15. COMPOSITE ELEMENT METHOD FOR SEEPAGE ANALYSIS OF GEOTECHNICAL STRUCTURES WITH DRAINAGE HOLE ARRAY

    Institute of Scientific and Technical Information of China (English)

    CHEN Sheng-hong; XU Qing; HU Jing

    2004-01-01

    Air element concept and Composite Element Method (CEM) were introduced in this paper firstly, and then an explicit drainage holes element model was developed. The main advantage of the new model is that it allows drainage holes to be located within soil elements. Therefore the mesh generation of complicated geotechnical structures with a large number of seepage drainage holes becomes relatively convenient and feasible. This will further facilitate the optimal design of seepage control system, and in this case the calculation mesh can be kept unchanged when the number, position and orientation of drainage holes are adjusted. The model was been implemented in software. A sluice foundation seepage control problem was studied, by which the validity and the robustness of the new model were verified.

  16. Mechanical property analysis of kenaf–glass fibre reinforced polymer composites using finite element analysis

    Indian Academy of Sciences (India)

    M Ramesh; S Nijanthan

    2016-02-01

    Nowadays, natural fibres are used as a reinforcing material in polymer composites, owing to severe environmental concerns. Among many different types of natural resources, kenaf plants have been extensively exploited over the past few years. In this experimental study, partially eco-friendly hybrid composites were fabricated by using kenaf and glass fibres with two different fibre orientations of 0° and 90°. The mechanical properties such as tensile, flexural and impact strengths of these composites have been evaluated. From the experiment, it was observed that the composites with the 0° fibre orientation can withstand the maximum tensile strength of 49.27 MPa, flexural strength of 164.35 MPa, and impact strength of 6 J. Whereas, the composites with the 90° fibre orientation hold the maximum tensile strength of 69.86 MPa, flexural strength of 162.566 MPa and impact strength of 6.66 J. The finite element analysis was carried out to analyse the elastic behaviour of the composites and to predict the mechanical properties by using NX Nastran 9.0 software. The experimental results were compared with the predicted values and a high correlation between the results was observed. The morphology of the fractured surfaces of the composites was analysed using a scanning electron microscopy analysis. The results indicated that the properties were in the increasing trend and comparable with pure synthetic fibre reinforced composites, which shows the potential for hybridization of kenaf fibre with glass fibre.

  17. Dissection of human vitreous body elements for proteomic analysis.

    Science.gov (United States)

    Skeie, Jessica M; Mahajan, Vinit B

    2011-01-23

    The vitreous is an optically clear, collagenous extracellular matrix that fills the inside of the eye and overlies the retina. (1,2) Abnormal interactions between vitreous substructures and the retina underlie several vitreoretinal diseases, including retinal tear and detachment, macular pucker, macular hole, age-related macular degeneration, vitreomacular traction, proliferative vitreoretinopathy, proliferative diabetic retinopathy, and inherited vitreoretinopathies. (1,2) The molecular composition of the vitreous substructures is not known. Since the vitreous body is transparent with limited surgical access, it has been difficult to study its substructures at the molecular level. We developed a method to separate and preserve these tissues for proteomic and biochemical analysis. The dissection technique in this experimental video shows how to isolate vitreous base, anterior hyaloid, vitreous core, and vitreous cortex from postmortem human eyes. One-dimensional SDS-PAGE analyses of each vitreous component showed that our dissection technique resulted in four unique protein profiles corresponding to each substructure of the human vitreous body. Identification of differentially compartmentalized proteins will reveal candidate molecules underlying various vitreoretinal diseases.

  18. Multi-Element Composition of Honey as a Suitable Tool for Its Authenticity Analysis

    Directory of Open Access Journals (Sweden)

    Oroian Mircea

    2015-06-01

    Full Text Available The aim of this study was to evaluate the composition of 36 honey samples of 4 different botanical origins (acacia, sun flower, tilia and honeydew from the North East region of Romania. An inductively coupled plasma-mass spectrometry (ICP-MS method was used to determine 27 elements in honey (Ag, Al, As, Ba, Be, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, K, Li, Mg, Mn, Na, Ni, Pb, Rb, Se, Sr, Tl, U, V and Zn. We would like to achieve the following goal: to demonstrate that the qualitative and quantitative multi-element composition determination of honey can be used as a suitable tool to classify honey according to its botanical origin. The principal component analysis allowed the reduction of the 27 variables to 2 principal components which explained 74% of the total variance. The dominant elements which were strongly associated with the principal component were K, Mg and Ca. Discriminant models obtained for each kind of botanical honey confirmed that the differentiation of honeys according to their botanical origin was mainly based on multi-element composition. A correct classification of all samples was achieved with the exception of 11.1% of honeydew honeys.

  19. Humic substances elemental composition of selected taiga and tundra soils from Russian European North-East

    Directory of Open Access Journals (Sweden)

    Lodygin Evgeny

    2017-06-01

    Full Text Available Soils of Russian European North were investigated in terms of stability and quality of organic matter as well as in terms of soils organic matter elemental composi­tion. Therefore, soil humic acids (HAs, extracted from soils of different natural zones of Russian North-East were studied to characterize the degree of soil organic matter stabilization along a zonal gradient. HAs were extracted from soil of different zonal environments of the Komi Republic: south, middle and north taiga as well as south tundra. Data on elemental composition of humic acids and fulvic acids (FAs extracted from different soil types were obtained to assess humus formation mechanisms in the soils of taiga and tundra of the European North-East of Russia. The specificity of HAs elemental composition are discussed in relation to environmental conditions. The higher moisture degree of taiga soils results in the higher H/C ratio in humic substances. This reflects the reduced microbiologic activity in Albeluvisols sods and subsequent conser­vation of carbohydrate and amino acid fragments in HAs. HAs of tundra soils, shows the H/C values decreasing within the depth of the soils, which reflects increasing of aromatic compounds in HA structure of mineral soil horizons. FAs were more oxidized and contains less carbon while compared with the HAs. Humic acids, extracted from soil of different polar and boreal environments differ in terms of elemental composition winch reflects the climatic and hydrological regimes of humification.

  20. Biogeochemical interactions control a temporal succession in the elemental composition of marine communities

    KAUST Repository

    Martiny, Adam C.

    2015-11-23

    Recent studies have revealed clear regional differences in the particulate organic matter composition and stoichiometry of plankton communities. In contrast, less is known about potential mechanisms and patterns of temporal changes in the elemental composition of marine systems. Here, we monitored weekly changes in environmental conditions, phytoplankton abundances, and particulate organic carbon, nitrogen, and phosphorus concentrations over a 3-yr period. We found that variation in the particulate organic matter (POM) concentrations and ratios were related to seasonal oscillations of environmental conditions and phytoplankton abundances. Periods with low temperature, high nutrient concentrations and a dominance of large phytoplankton corresponded to low C : N : P and vice-versa for warmer periods during the summer and fall. In addition to seasonal changes, we observed a multiyear increase in POM C : P and N : P that might be associated with the Pacific Decadal Oscillation. Finally, there was substantial short-term variability in all factors but similar linkages between environmental variability and elemental composition as observed on seasonal and interannual time-scales. Using a feed-forward neural network, we could explain a large part of the variation in POM concentrations and ratios based on changes in environmental conditions and phytoplankton abundances. The apparent links across all time-scales between changes in physics, chemistry, phytoplankton, and POM concentrations and ratios suggest we have identified key controls of the elemental composition of marine communities in this region.

  1. Human Health Countermeasures (HHC) Element Management Plan: Human Research Program. Revision B

    Science.gov (United States)

    Norsk, Peter; Baumann, David

    2012-01-01

    NASA s Human Research Program (HRP) is an applied research and technology program within the Human Exploration and Operations Mission Directorate (HEOMD) that addresses human health and performance risk mitigation strategies in support of exploration missions. The HRP research and technology development is focused on the highest priority risks to crew health and safety with the goal of ensuring mission success and maintaining long-term crew health. Crew health and performance standards, defined by the NASA Chief Health and Medical Officer (CHMO), set the acceptable risk level for exploration missions. The HRP conducts research to inform these standards as well as provide deliverables, such as countermeasures, that ensure standards can be met to maximize human performance and mission success. The Human Health Countermeasures (HHC) Element was formed as part of the HRP to develop a scientifically-based, integrated approach to understanding and mitigating the health risks associated with human spaceflight. These health risks have been organized into four research portfolios that group similar or related risks. A fifth portfolio exists for managing technology developments and infrastructure projects. The HHC Element portfolios consist of: a) Vision and Cardiovascular; b) Exercise and Performance; c) Multisystem; d) Bone; and e) Technology and Infrastructure. The HHC identifies gaps associated with the health risks and plans human physiology research that will result in knowledge required to more fully understand risks and will result in validated countermeasures to mitigate risks.

  2. Layerwise mechanics and finite element for the dynamic analysis of piezoelectric composite plates

    Science.gov (United States)

    Saravanos, Dimitris A.; Heyliger, Paul R.; Hopkins, Dale A.

    1996-01-01

    Laminate and structural mechanics for the analysis of laminated composite plate structures with piezoelectric actuators and sensors are presented. The theories implement layerwise representations of displacements and electric potential, and can model both the global and local electromechanical response of smart composite laminates. Finite-element formulations are developed for the quasi-static and dynamic analysis of smart composite structures containing piezoelectric layers. Comparisons with an exact solution illustrate the accuracy, robustness and capability of the developed mechanics to capture the global and local response of thin and/or thick laminated piezoelectric plates. Additional correlations and numerical applications demonstrate the unique capabilities of the mechanics in analyzing the static and free-vibration response of composite plates with distributed piezoelectric actuators and sensors.

  3. Coupled mixed-field laminate theory and finite element for smart piezoelectric composite shell structures

    Science.gov (United States)

    Saravanos, Dimitris A.

    1996-01-01

    Mechanics for the analysis of laminated composite shells with piezoelectric actuators and sensors are presented. A new mixed-field laminate theory for piezoelectric shells is formulated in curvilinear coordinates which combines single-layer assumptions for the displacements and a layerwise representation for the electric potential. The resultant coupled governing equations for curvilinear piezoelectric laminates are described. Structural mechanics are subsequently developed and an 8-node finite-element is formulated for the static and dynamic analysis of adaptive composite structures of general laminations containing piezoelectric layers. Evaluations of the method and comparisons with reported results are presented for laminated piezoelectric-composite plates, a closed cylindrical shell with a continuous piezoceramic layer and a laminated composite semi-circular cantilever shell with discrete cylindrical piezoelectric actuators and/or sensors.

  4. Human body composition models and methodology: theory and experiment.

    NARCIS (Netherlands)

    Wang, Z.M.

    1997-01-01

    The study of human body composition is a branch of human biology which focuses on the in vivo quantification of body components, the quantitative relationships between components, and the quantitative changes in these components related to various influencing factors. Accordingly, the study of human

  5. Trace Elements Composition of Achatina achatina Samples from the Madina Market in Accra, Ghana

    Directory of Open Access Journals (Sweden)

    A.K. Anim

    2011-08-01

    Full Text Available This research was carried out to assess the composition and sources of trace elements in seventeen Achatina achatina samples obtained from the Madina Market. The trace elements were analyzed using Atomic Absorption Spectrophotometer (VARIAN AA 240 FS and Instrumental Neutron Activation Analysis (INAA. The highest mean Concentration, 2240.5 mg/kg was measured for chlorine while the least mean concentration, 0.13 mg/kg was measured for Magnessium. The mean elemental Concentrations were in the order Cl>Ca>Na>Al>Fe>Cu>Zn>Ni>Mn>K>V>Mg. Pearson Correlation matrix, Principal Component(PC Analysis and Hierarchical Cluster Analysis (CA shows varying sources of the trace elements, however there is great interrelationships regarding their sources. The correlation matrix at 99% confidence level loaded the components Al-Fe-Mn, Ca-Cl-Mg, Cl-Mg-Na, Fe-V, and Ni-V. PC1 which loaded Ca, Cl, Mg, Na, Ni, and V agrees very well with CA1. A similar trend is shown in CA2 and PC2 with Al, Fe and Mn loadings. The geology of the original habitat of the samples which is characterized by Shales, Quartzite and Feldsphalthic sandstone together with anthropogenic inputs from fertilizers, pesticides, and herbicides have been identified as the possible sources of the elements. All the elements analysed in the samples were essential elements.

  6. A study on temporal variation of elemental composition in tree barks used as air pollution indicators

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Eliane C.; Saiki, Mitiko, E-mail: eliane_csantos@yahoo.com.br, E-mail: mitiko@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The study of air pollution using biological matrices has shown that tree barks may be used as biomonitor due to accumulation of aerosol particles on its porous surface. The bark elemental composition can provide information on pollution sources as well as characterize the aerial pollutants from a wide geographical region. The aim of this study was to investigate the variation in elemental composition in barks with time of exposure. Tree barks from Tipuana (Tipuana tipu) and Sibipiruna (Caesalpinia peltophoroides) species were collected in February 2013 and July 2014 in the city of São Paulo. For analysis, the barks were cleaned, grated, ground and analyzed by neutron activation analysis (NAA). Aliquots of samples and synthetic standards of elements were irradiated with thermal neutron flux at the IEA-R1 nuclear research reactor and after a suitable decay time, the induced gamma activities were analyzed by gamma spectrometry. The elements As, Br, Ca, Co, Cr, Cs, Fe, K, La, Rb, Sb, Sc and Zn were determined and the results indicated variability in the concentrations depending on the element, sampling period and also on tree species, indicating that there are not very well defined temporal trends. The quality control of the analytical results evaluated by analyzing INCT Virginia Tobacco Leaves certified reference material (CRM) presented values of |z-score| < 2, indicating that the procedure of NAA applied is suitable for the analyses. (author)

  7. Finite Element Analysis of External Thermal Insulation Composite System: Thin Rendered Expanded Polystyrene Board

    Institute of Scientific and Technical Information of China (English)

    BO Hai-tao; LI Hui-qiang; YIN Xiu-qin

    2009-01-01

    The finite element model of an external thermal composite insulation system, thin rendered expanded polystyrene (EPS) board, was built with ANSYS 1.0, which had two forms: one with window and one without window. The finite element analysis results show that the EPS board had very good insulation capacity at both high or low temperature, stress concentration was produced in the center of wall and around window, and the maximum deformation was observed at the edge of board and the minimum deformation was in the center.

  8. Analysis of Composite Transverse Mechanical Properties Based on Micromechanical Finite Element Method

    Directory of Open Access Journals (Sweden)

    LIU Wan-lei

    2016-11-01

    Full Text Available Transverse fracture often occurs early in the loading history and is one of the key issues limiting the composite structural design. However, the mechanical behavior under transverse loading can not be represented by traditional micromechanical model which does not consider the influence of constituent properties, fiber volume fraction and fiber distribution. A new computational micromechanics finite element method, which the microstructure was idealized as a random dispersion of parallel fibers embedded in the polymeric matrix using improved random sequence absorption algorithm, was presented. The plasticity of matrix and interface decohesion of the composite were included in this model and the residual stress caused by the cooling of composite after the curing process was also taken into consideration. The transverse tension, compression and shear of composite were analyzed by the micromechanical finite element method. Compared with the experiment results, the prediction errors of transverse module were less than 7%, and the transverse compression strength and shear strength were less than 8%. The results demonstrate that the method proposed here can be used to predict the composite transverse behavior.

  9. Ballistic impact behaviour of woven fabric composite: Finite element analysis and experiments

    Science.gov (United States)

    Phadnis, V. A.; Pandya, K. S.; Naik, N. K.; Roy, A.; Silberschmidt, V. V.

    2013-07-01

    A mechanical behaviour of plain-weave E-glass fabric/epoxy laminate composite plate exposed to ballistic impact is studied using a finite-element (FE) code Abaqus/Explicit. A ply-level FE model is developed, where a fabric-reinforced ply is modelled as a homogeneous orthotropic elastic material with potential to sustain progressive stiffness degradation due to fiber/matrix cracking, and plastic deformation under shear loading. The model is implemented as a VUMAT user subroutine. Ballistic experiments were carried out to validate the FE model. A parametric study for varying panel thickness is performed to compare impact resistance of the studied composite.

  10. Influence of rare earth element Y on composition, microstructure and inclusion of the weld

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the influence of rare element Y on the composition, microstructure and inclusions of the weld metal has been studied by using the method of "alloy addition in a molten pool". The results show: (1) The composition of the weld metal is not obviously affected by little amount of Y-SiFe addition. (2) Y-SiFe can make weld microstructure fine and raise the hardness of the weld. (3) Y-SiFe has not obvious influence on the inclusion size. (4) When the amount of Y is a little, Y accumulates in the silicates of Ti, Mn and other compound inclusion with MnS.

  11. X-ray based micromechanical finite element modeling of composite materials

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard; Emerson, Monica Jane; Jespersen, Kristine Munk;

    2016-01-01

    This is a study of a uni-directional non-crimp fabric reinforced epoxy composite material typically used as the load carrying laminate in wind turbine blades. Based on a 3D xray tomography scan, the bundle and fibre/matrix structure of the composite is segmented. This segmentation is used in a mu...... in a multi-scale finite element model bridging the gap from the individual fibers organized in bundles to the stitched non-crimp fabric used for building up the load carrying laminates....

  12. Template polymerization synthesis of hydrogel and silica composite for sorption of some rare earth elements.

    Science.gov (United States)

    Borai, E H; Hamed, M G; El-kamash, A M; Siyam, T; El-Sayed, G O

    2015-10-15

    New sorbents containing 2-acrylamido 2-methyl propane sulphonic acid monomer onto poly(vinyl pyrilidone) P(VP-AMPS) hydrogel and P(VP-AMPS-SiO2) composite have been synthesized by radiation template polymerization. The effect of absorbed dose rate (kGy), crosslinker concentration and polymer/monomer ratio on the degree of template polymerization of P(VP-AMPS) hydrogel was studied. The degree of polymerization was evaluated by the calculated percent conversion and swelling degree. The maximum capacity of P(VP-AMPS) hydrogel toward Cu(+2) metal ion found to be 91 mg/gm. The polymeric composite P(VP-AMPS-SiO2) has been successfully synthesized. The structure of the prepared hydrogel and composite were confirmed by FTIR, thermal analysis (TGA and DTA) and SEM micrograph. Batch adsorption studies for La(3+), Ce(3+), Nd(3+), Eu(3+) and Pb(+2) metal ions on the prepared hydrogel and composite were investigated as a function of shaking time, pH and metal ion concentration. The sorption efficiency of the prepared hydrogel and composite toward light rare earth elements (LREEs) are arranged in the order La(3+)>Ce(3+)>Nd(3+)>Eu(3+). The obtained results demonstrated the superior adsorption capacity of the composite over the polymeric hydrogel. The maximum capacity of the polymeric composite was found to be 116, 103, 92, 76, 74 mg/gm for La(3+), Ce(3+), Nd(3+), Eu(3+) and Pb(2+) metal ions respectively.

  13. Lineage specific evolution of the VNTR composite retrotransposon central domain and its role in retrotransposition of gibbon LAVA elements.

    Science.gov (United States)

    Lupan, Iulia; Bulzu, Paul; Popescu, Octavian; Damert, Annette

    2015-05-16

    VNTR (Variable Number of Tandem Repeats) composite retrotransposons - SVA (SINE-R-VNTR-Alu), LAVA (LINE-1-Alu-VNTR-Alu), PVA (PTGR2-VNTR-Alu) and FVA (FRAM-VNTR-Alu) - are specific to hominoid primates. Their assembly, the evolution of their 5' and 3' domains, and the functional significance of the shared 5' Alu-like region are well understood. The central VNTR domain, by contrast, has long been assumed to represent a more or less random collection of 30-50 bp GC-rich repeats. It is only recently that it attracted attention in the context of regulation of SVA expression. Here we provide evidence that the organization of the VNTR is non-random, with conserved repeat unit (RU) arrays at both the 5' and 3' ends of the VNTRs of human, chimpanzee and orangutan SVA and gibbon LAVA. The younger SVA subfamilies harbour highly organized internal RU arrays. The composition of these arrays is specific to the human/chimpanzee and orangutan lineages, respectively. Tracing the development of the VNTR through evolution we show for the first time how tandem repeats evolve within the constraints set by a functional, non-autonomous non-LTR retrotransposon in two different families - LAVA and SVA - in different hominoid lineages. Our analysis revealed that a microhomology-driven mechanism mediates expansion/contraction of the VNTR domain at the DNA level. Elements of all four VNTR composite families have been shown to be mobilized by the autonomous LINE1 retrotransposon in trans. In case of SVA, key determinants of mobilization are found in the 5' hexameric repeat/Alu-like region. We now demonstrate that in LAVA, by contrast, the VNTR domain determines mobilization efficiency in the context of domain swaps between active and inactive elements. The central domain of VNTR composites evolves in a lineage-specific manner which gives rise to distinct structures in gibbon LAVA, orangutan SVA, and human/chimpanzee SVA. The differences observed between the families and lineages are likely to

  14. Trace elements in human physiology and pathology: zinc and metallothioneins.

    Science.gov (United States)

    Tapiero, Haim; Tew, Kenneth D

    2003-11-01

    Zinc is one of the most abundant nutritionally essential elements in the human body. It is found in all body tissues with 85% of the whole body zinc in muscle and bone, 11% in the skin and the liver and the remaining in all the other tissues. In multicellular organisms, virtually all zinc is intracellular, 30-40% is located in the nucleus, 50% in the cytoplasm, organelles and specialized vesicles (for digestive enzymes or hormone storage) and the remainder in the cell membrane. Zinc intake ranges from 107 to 231 micromol/d depending on the source, and human zinc requirement is estimated at 15 mg/d. Zinc has been shown to be essential to the structure and function of a large number of macromolecules and for over 300 enzymic reactions. It has both catalytic and structural roles in enzymes, while in zinc finger motifs, it provides a scaffold that organizes protein sub-domains for the interaction with either DNA or other proteins. It is critical for the function of a number of metalloproteins, inducing members of oxido-reductase, hydrolase ligase, lyase family and has co-activating functions with copper in superoxide dismutase or phospholipase C. The zinc ion (Zn(++)) does not participate in redox reactions, which makes it a stable ion in a biological medium whose potential is in constant flux. Zinc ions are hydrophilic and do not cross cell membranes by passive diffusion. In general, transport has been described as having both saturable and non-saturable components, depending on the Zn(II) concentrations involved. Zinc ions exist primarily in the form of complexes with proteins and nucleic acids and participate in all aspects of intermediary metabolism, transmission and regulation of the expression of genetic information, storage, synthesis and action of peptide hormones and structural maintenance of chromatin and biomembranes.

  15. Cytotoxic effects of composite dust on human bronchial epithelial cells.

    Science.gov (United States)

    Cokic, Stevan M; Hoet, Peter; Godderis, Lode; Wiemann, Martin; Asbach, Christof; Reichl, Franz X; De Munck, Jan; Van Meerbeek, Bart; Van Landuyt, Kirsten L

    2016-12-01

    Previous research revealed that during routine abrasive procedures like polishing, shaping or removing of composites, high amounts of respirable dust particles (composite dust particles on bronchial epithelium cells. Composite dust of five commercial composites (one nano-composite, two nano-hybrid and two hybrid composites) was generated following a clinically relevant protocol. Polymerized composite samples were cut with a rough diamond bur (grain size 100μm, speed 200,000rpm) and all composite dust was collected in a sterile chamber. Human bronchial epithelial cells (16HBE14o-) were exposed to serially diluted suspensions of composite dust in cell culture medium at concentrations between 1.1 and 3.3mg/ml. After 24h-exposure, cell viability and membrane integrity were assessed by the WST-1 and the LDH leakage assay, respectively. The release of IL-1β and IL-6 was evaluated. The composite dust particles were characterized by transmission electron microscopy and by dynamic and electrophoretic light scattering. Neither membrane damage nor release of IL-1β was detected over the complete concentration range. However, metabolic activity gradually declined for concentrations higher than 660μg/ml and the release of IL-6 was reduced when cells were exposed to the highest concentrations of dust. Composite dust prepared by conventional dental abrasion methods only affected human bronchial epithelial cells in very high concentrations. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Research of essential elements composition in the cerebrospinal fluid in patients with outcomes of traumatic brain injury

    OpenAIRE

    Aliev, M. A.; MAMADALIEV A.M.; MAMADALIEVA S.A.

    2015-01-01

    The aim of this research is to investigate the essential elements composition in the cerebrospinal fluid of patients with different outcomes of traumatic brain injury before and after complex treatment with the use of endolumbal and intracystal introduction of ozone and pyracetam in dynamics. Essential elements composition was investigated in the cerebrospinal fluid of 83 patients. Thus, it may be noted positive changes in the metabolism of essential elements in the cerebrospinal fluid of pat...

  17. An element-based finite-volume method approach for naturally fractured compositional reservoir simulation

    Energy Technology Data Exchange (ETDEWEB)

    Marcondes, Francisco [Federal University of Ceara, Fortaleza (Brazil). Dept. of Metallurgical Engineering and Material Science], e-mail: marcondes@ufc.br; Varavei, Abdoljalil; Sepehrnoori, Kamy [The University of Texas at Austin (United States). Petroleum and Geosystems Engineering Dept.], e-mails: varavei@mail.utexas.edu, kamys@mail.utexas.edu

    2010-07-01

    An element-based finite-volume approach in conjunction with unstructured grids for naturally fractured compositional reservoir simulation is presented. In this approach, both the discrete fracture and the matrix mass balances are taken into account without any additional models to couple the matrix and discrete fractures. The mesh, for two dimensional domains, can be built of triangles, quadrilaterals, or a mix of these elements. However, due to the available mesh generator to handle both matrix and discrete fractures, only results using triangular elements will be presented. The discrete fractures are located along the edges of each element. To obtain the approximated matrix equation, each element is divided into three sub-elements and then the mass balance equations for each component are integrated along each interface of the sub-elements. The finite-volume conservation equations are assembled from the contribution of all the elements that share a vertex, creating a cell vertex approach. The discrete fracture equations are discretized only along the edges of each element and then summed up with the matrix equations in order to obtain a conservative equation for both matrix and discrete fractures. In order to mimic real field simulations, the capillary pressure is included in both matrix and discrete fracture media. In the implemented model, the saturation field in the matrix and discrete fractures can be different, but the potential of each phase in the matrix and discrete fracture interface needs to be the same. The results for several naturally fractured reservoirs are presented to demonstrate the applicability of the method. (author)

  18. The effect of lipid content on the elemental composition and energy capacity of yeast biomass.

    Science.gov (United States)

    Minkevich, Igor G; Dedyukhina, Emiliya G; Chistyakova, Tat'yana I

    2010-10-01

    Oleaginous yeasts (18 strains) were grown in ethanol media under various cultivation conditions (33 biomass samples). It was found that lipid and lipid-free fractions of dry biomass have elemental composition and biomass reductivity very close to values which can be considered as biological constants. The energy content of dry biomass strongly depended on the total lipid content. When the lipid content was 64%, the energy value of dry biomass reached 73% of diesel oil; therefore, oleaginous microorganisms can be a promising source of biodiesel fuel. The approach used in this work makes it possible to determine the energy value of biomass by its elemental composition without application of laborious and expensive calorimetric measurements of combustion heats.

  19. Immunogenic compositions comprising human immunodeficiency virus (HIV) mosaic Nef proteins

    Science.gov (United States)

    Korber, Bette T [Los Alamos, NM; Perkins, Simon [Los Alamos, NM; Bhattacharya, Tanmoy [Los Alamos, NM; Fischer, William M [Los Alamos, NM; Theiler, James [Los Alamos, NM; Letvin, Norman [Boston, MA; Haynes, Barton F [Durham, NC; Hahn, Beatrice H [Birmingham, AL; Yusim, Karina [Los Alamos, NM; Kuiken, Carla [Los Alamos, NM

    2012-02-21

    The present invention relates to mosaic clade M HIV-1 Nef polypeptides and to compositions comprising same. The polypeptides of the invention are suitable for use in inducing an immune response to HIV-1 in a human.

  20. For a Few Howardites More: Grand Maps the Elemental Composition of Vesta

    Science.gov (United States)

    Prettman, T.; Reedy, R. C.; Mittlefehldt, David W.; Yamashita, N.; Lawrence, D. J.; Beck, A. W.; Feldman. W. C.; McCoy, T. J.; McSween, H. Y.; Toplis, M. J.; Forni, O.; Mizzon, H.; Raymond, C. A.; Russell, C. T.; Polanskey, C. A.; Joy, S. P.; Mafi, J.

    2012-01-01

    Dawn?s Gamma Ray and Neutron Detector (GRaND) successfully completed Low Altitude Mapping Orbit (LAMO) at Vesta. Over four months were spent acquiring data in a 460-km radius orbit around Vesta (265-km mean radius). In LAMO, strong signatures from Vesta were observed for gamma rays and neutrons. We present preliminary abundances, detection limits, and global maps of the elemental composition of Vesta.

  1. Finite Element Verification of Non-Homogeneous Strain and Stress Fields during Composite Material Testing

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    2015-01-01

    strength and fatigue performance is essential. Nevertheless, testing composites includes some challenges regarding stiffness determination using conventional strain gauges and achieving correct material failure unaffected by the gripping region during fatigue testing. Challenges, which in the present study......, has been addressed using the finite element method. During this, a verification of experimental observations, a deeper understanding on the test coupon loading and thereby improved test methods has been achieved....

  2. Antimicrobial Activity and Elemental Composition of Sarcocephalus latifolius Fruits: An Ethnopharmacological Based Evaluation

    OpenAIRE

    Alsiddig Osama; Sufyan Awadelkarim; Mai Omer; Saga Yasser; Yousra Basher; Thoyba Elmabrouk; Afnan Abdalmaged

    2017-01-01

    Sarcocephalus latifolius have been part of Sudanese ethnomedicine since long time. The current study was conducted to evaluate the antimicrobial activity of Sarcocephalus latifolius fruits and to investigate its elemental composition. The antimicrobial activities of the ethanolic crude extract and solvents fractions (hexane chloroform, acetone and aqua’s) were investigated by the disk diffusion method. These fractions were further screened for the presence of eight secondary metabolites using...

  3. Application of the quadrilateral area coordinate method: a new element for laminated composite plate bending problems

    Institute of Scientific and Technical Information of China (English)

    Song Cen; Xiangrong Fu; Yuqiu Long; Hongguang Li; Zhenhan Yao

    2007-01-01

    Recently, some new quadrilateral finite elements were successfully developed by the Quadrilateral Area Coordinate (QAC) method. Compared with those traditional models using isoparametric coordinates, these new models are less sensitive to mesh distortion. In this paper, a new displacement-based, 4-node 20-DOF (5-DOF per node)quadrilateral bending element based on the first-order shear deformation theory for analysis of arbitrary laminated composite plates is presented. Its bending part is based on the element AC-MQ4, a recent-developed high-performance Mindlin-Reissner plate element formulated by QAC method and the generalized conforming condition method; and its in-plane displacement fields are interpolated by bilinear shape functions in isoparametric coordinates. Furthermore,the hybrid post-processing procedure, which was firstly proposed by the authors, is employed again to improve the stress solutions, especially for the transverse shear stresses. The resulting element, denoted as AC-MQ4-LC, exhibits excellent performance in all linear static and dynamic numerical examples. It demonstrates again that the QAC method, the generalized conforming condition method, and the hybrid post-processing procedure are efficient tools for developing simple, effective and reliable finite element models.

  4. Finite element modelling of woven composite failure modes at the mesoscopic scale: deterministic versus stochastic approaches

    Science.gov (United States)

    Roirand, Q.; Missoum-Benziane, D.; Thionnet, A.; Laiarinandrasana, L.

    2017-09-01

    Textile composites are composed of 3D complex architecture. To assess the durability of such engineering structures, the failure mechanisms must be highlighted. Examinations of the degradation have been carried out thanks to tomography. The present work addresses a numerical damage model dedicated to the simulation of the crack initiation and propagation at the scale of the warp yarns. For the 3D woven composites under study, loadings in tension and combined tension and bending were considered. Based on an erosion procedure of broken elements, the failure mechanisms have been modelled on 3D periodic cells by finite element calculations. The breakage of one element was determined using a failure criterion at the mesoscopic scale based on the yarn stress at failure. The results were found to be in good agreement with the experimental data for the two kinds of macroscopic loadings. The deterministic approach assumed a homogeneously distributed stress at failure all over the integration points in the meshes of woven composites. A stochastic approach was applied to a simple representative elementary periodic cell. The distribution of the Weibull stress at failure was assigned to the integration points using a Monte Carlo simulation. It was shown that this stochastic approach allowed more realistic failure simulations avoiding the idealised symmetry due to the deterministic modelling. In particular, the stochastic simulations performed have shown several variations of the stress as well as strain at failure and the failure modes of the yarn.

  5. The prediction of elemental composition of biomass based on proximate analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shen Jianfeng [School of Power Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China); Zhu Shuguang, E-mail: zhushuguang@tsinghua.org.c [School of Power Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China); Liu Xinzhi; Zhang Houlei; Tan Junjie [School of Power Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China)

    2010-05-15

    Elemental composition is one of the most important properties for biomass utilization. The experimental determination of ultimate analysis data require special instrumentation, while proximate analysis data can be obtained easily by using common equipments. This paper presents new correlations for calculating the elemental composition based on proximate analysis of biomass. The correlations with the effect of ash content taken into account are derived by using 66 data points, and validated by using 20 data points selected from different categories of biomass than that for correlations derivation. The correlations are given as: C = 0.635FC + 0.460VM - 0.095ASH, H = 0.059FC + 0.060VM + 0.010ASH, O = 0.340FC + 0.469VM - 0.023ASH, where 9.2% <= FC <= 32.79%, 57.2% <= VM <= 90.6%, 0.1% <= ASH <= 24.6%, 36.2% <= C <= 53.1%, 4.7% <= H <= 6.61%, and 31.37% <= O <= 48.0% in wt.% on dry basis. The average absolute errors of these correlations are 3.17%, 4.47% and 3.16%, and the average bias errors are 0.19%, -0.34% and 0.19% compared with measured values of C, H and O, respectively. The new developed correlations can be used to compute elemental composition of biomass accurately, especially for those biomass whose ash content are high, based on simple proximate analysis.

  6. The prediction of elemental composition of biomass based on proximate analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jianfeng Shen; Shuguang Zhu; Xinzhi Liu; Houlei Zhang; Junjie Tan [School of Power Engineering, Nanjing University of Science and Technology, Xiaolingwei 200, Nanjing 210094 (China)

    2010-05-15

    Elemental composition is one of the most important properties for biomass utilization. The experimental determination of ultimate analysis data require special instrumentation, while proximate analysis data can be obtained easily by using common equipments. This paper presents new correlations for calculating the elemental composition based on proximate analysis of biomass. The correlations with the effect of ash content taken into account are derived by using 66 data points, and validated by using 20 data points selected from different categories of biomass than that for correlations derivation. The correlations are given as: C = 0.635FC + 0.460VM - 0.095ASH, H = 0.059FC + 0.060VM + 0.010ASH, O = 0.340FC + 0.469VM - 0.023ASH, where 9.2% {<=} FC {<=} 32.79%, 57.2% {<=} VM {<=} 90.6%, 0.1% {<=} ASH {<=} 24.6%, 36.2% {<=} C {<=} 53.1%, 4.7% {<=} H {<=} 6.61%, and 31.37% {<=} O {<=} 48.0% in wt.% on dry basis. The average absolute errors of these correlations are 3.17%, 4.47% and 3.16%, and the average bias errors are 0.19%, -0.34% and 0.19% compared with measured values of C, H and O, respectively. The new developed correlations can be used to compute elemental composition of biomass accurately, especially for those biomass whose ash content are high, based on simple proximate analysis. (author)

  7. A Mixed Multi-Field Finite Element Formulation for Thermopiezoelectric Composite Shells

    Science.gov (United States)

    Lee, Ho-Jun; Saravanos, Dimitris A.

    1999-01-01

    Analytical formulations are presented which account for the coupled mechanical, electrical, and thermal response of piezoelectric composite shell structures. A new mixed multi-field laminate theory is developed which combines "single layer" assumptions for the displacements along with layerwise fields for the electric potential and temperature. This laminate theory is formulated using curvilinear coordinates and is based on the principles of linear thermopiezoelectricity. The mechanics have the inherent capability to explicitly model both the active and sensory responses of piezoelectric composite shells in thermal environment. Finite element equations are derived and implemented for an eight-noded shell element. Numerical studies are conducted to investigate both the sensory and active responses of piezoelectric composite shell structures subjected to thermal loads. Results for a cantilevered plate with an attached piezoelectric layer are com- pared with corresponding results from a commercial finite element code and a previously developed program. Additional studies are conducted on a cylindrical shell with an attached piezoelectric layer to demonstrate capabilities to achieve thermal shape control on curved piezoelectric structures.

  8. Elemental and iron isotopic composition of aerosols collected in a parking structure.

    Science.gov (United States)

    Majestic, Brian J; Anbar, Ariel D; Herckes, Pierre

    2009-09-01

    The trace metal contents and iron isotope composition of size-resolved aerosols were determined in a parking structure in Tempe, AZ, USA. Particulate matter (PM)2.5 microm were collected. Several air toxics (e.g., arsenic, cadmium, and antimony) were enriched above the crustal average, implicating automobiles as an important source. Extremely high levels of fine copper (up to 1000 ng m(-3)) were also observed in the parking garage, likely from brake wear. The iron isotope composition of the aerosols were found to be +0.15+/-0.03 per thousand and +0.18+/-0.03 per thousand for the PM2.5 microm fractions, respectively. The similarity of isotope composition indicates a common source for each size fraction. To better understand the source of iron in the parking garage, the elemental composition in four brake pads (two semi-metallic and two ceramic), two tire tread samples, and two waste oil samples were determined. Striking differences in the metallic and ceramic brake pads were observed. The ceramic brake pads contained 10-20% copper by mass, while the metallic brake pads contained about 70% iron, with very little copper. Both waste oil samples contained significant amounts of calcium, phosphorous, and zinc, consistent with the composition of some engine oil additives. Differences in iron isotope composition were observed between the source materials; most notably between the tire tread (average=+0.02 per thousand) and the ceramic brake linings (average=+0.65 per thousand). Differences in isotopic composition were also observed between the metallic (average=+0.18 per thousand) and ceramic brake pads, implying that iron isotope composition may be used to resolve these sources. The iron isotope composition of the metallic brake pads was found to be identical to the aerosols, implying that brake dust is the dominant source of iron in a parking garage.

  9. Establishing the baseline level of repetitive element expression in the human cortex

    National Research Council Canada - National Science Library

    Tyekucheva, Svitlana; Yolken, Robert H; McCombie, W Richard; Parla, Jennifer; Kramer, Melissa; Wheelan, Sarah J; Sabunciyan, Sarven

    2011-01-01

    .... Hence, we performed whole transcriptome sequencing to investigate the expression of repetitive elements in human frontal cortex using postmortem tissue obtained from the Stanley Medical Research Institute...

  10. The Elemental Composition of High-Energy Cosmic Rays: Measurements with TRACER

    CERN Document Server

    Boyle, P J

    2008-01-01

    TRACER ('Transition Radiation Array for Cosmic Energetic Radiation') is a balloon borne instrument that has been developed to directly measure the composition and energy spectra of individual heavy elements up to 10^15 eV per particle. TRACER achieves a large geometric factor (5 m^2 sr) through the use of a Transition Radiation Detector utilizing arrays of single wire proportional tubes. TRACER has measured the energy spectra of the elements O, Ne, Mg, Si, S, Ar, Ca, and Fe. The energy spectra reach energies in excess of 10^14 eV per particle and exhibit nearly the same spectral index (2.65 +/- 0.05) for all elements.

  11. Multidisciplinary Simulation of Graphite-Composite and Cermet Fuel Elements for NTP Point of Departure Designs

    Science.gov (United States)

    Stewart, Mark E.; Schnitzler, Bruce G.

    2015-01-01

    This paper compares the expected performance of two Nuclear Thermal Propulsion fuel types. High fidelity, fluid/thermal/structural + neutronic simulations help predict the performance of graphite-composite and cermet fuel types from point of departure engine designs from the Nuclear Thermal Propulsion project. Materials and nuclear reactivity issues are reviewed for each fuel type. Thermal/structural simulations predict thermal stresses in the fuel and thermal expansion mis-match stresses in the coatings. Fluid/thermal/structural/neutronic simulations provide predictions for full fuel elements. Although NTP engines will utilize many existing chemical engine components and technologies, nuclear fuel elements are a less developed engine component and introduce design uncertainty. Consequently, these fuel element simulations provide important insights into NTP engine performance.

  12. Dynamic measurement of coal thermal properties and elemental composition of volatile matter during coal pyrolysis

    Directory of Open Access Journals (Sweden)

    Rohan Stanger

    2014-01-01

    Full Text Available A new technique that allows dynamic measurement of thermal properties, expansion and the elemental chemistry of the volatile matter being evolved as coal is pyrolysed is described. The thermal and other properties are measured dynamically as a function of temperature of the coal without the need for equilibration at temperature. In particular, the technique allows for continuous elemental characterisation of tars as they are evolved during pyrolysis and afterwards as a function of boiling point. The technique is demonstrated by measuring the properties of maceral concentrates from a coal. The variation in heats of reaction, thermal conductivity and expansion as a function of maceral composition is described. Combined with the elemental analysis, the results aid in the interpretation of the chemical processes contributing to the physical and thermal behaviour of the coal during pyrolysis. Potential applications in cokemaking studies are discussed.

  13. Shape and Stress Sensing of Multilayered Composite and Sandwich Structures Using an Inverse Finite Element Method

    Science.gov (United States)

    Cerracchio, Priscilla; Gherlone, Marco; Di Sciuva, Marco; Tessler, Alexander

    2013-01-01

    The marked increase in the use of composite and sandwich material systems in aerospace, civil, and marine structures leads to the need for integrated Structural Health Management systems. A key capability to enable such systems is the real-time reconstruction of structural deformations, stresses, and failure criteria that are inferred from in-situ, discrete-location strain measurements. This technology is commonly referred to as shape- and stress-sensing. Presented herein is a computationally efficient shape- and stress-sensing methodology that is ideally suited for applications to laminated composite and sandwich structures. The new approach employs the inverse Finite Element Method (iFEM) as a general framework and the Refined Zigzag Theory (RZT) as the underlying plate theory. A three-node inverse plate finite element is formulated. The element formulation enables robust and efficient modeling of plate structures instrumented with strain sensors that have arbitrary positions. The methodology leads to a set of linear algebraic equations that are solved efficiently for the unknown nodal displacements. These displacements are then used at the finite element level to compute full-field strains, stresses, and failure criteria that are in turn used to assess structural integrity. Numerical results for multilayered, highly heterogeneous laminates demonstrate the unique capability of this new formulation for shape- and stress-sensing.

  14. Elemental and isotopic fingerprint of Argentinean wheat. Matching soil, water, and crop composition to differentiate provenance.

    Science.gov (United States)

    Podio, Natalia S; Baroni, María V; Badini, Raúl G; Inga, Marcela; Ostera, Héctor A; Cagnoni, Mariana; Gautier, Eduardo A; García, Pilar Peral; Hoogewerff, Jurian; Wunderlin, Daniel A

    2013-04-24

    The aim of this study was to investigate if elemental and isotopic signatures of Argentinean wheat can be used to develop a reliable fingerprint to assess its geographical provenance. For this pilot study we used wheat cultivated at three different regions (Buenos Aires, Córdoba, and Entre Ríos), together with matching soil and water. Elemental composition was determined by ICP-MS. δ(13)C and δ(15)N were measured by isotopic ratio mass spectrometry, while (87)Sr/(86)Sr ratio was determined using thermal ionization mass spectrometry. Wheat samples from three sampling sites were differentiated by the combination of 11 key variables (K/Rb, Ca/Sr, Ba, (87)Sr/(86)Sr, Co, Mo, Zn, Mn, Eu, δ(13)C, and Na), demonstrating differences among the three studied regions. The application of generalized Procrustes analysis showed 99.2% consensus between cultivation soil, irrigation water, and wheat samples, in addition to clear differences between studied areas. Furthermore, canonical correlation analysis showed significant correlation between the elemental and isotopic profiles of wheat and those corresponding to both soil and water (r(2) = 0.97, p wheat samples using different statistical methods, showing that wheat elemental and isotopic compositions are mainly related to soil and irrigation water characteristics of the site of growth.

  15. Mobilisation of toxic elements in the human respiratory system

    Energy Technology Data Exchange (ETDEWEB)

    Pinheiro, T. E-mail: murmur@itn1.itn.pt; Alves, L.C.; Palhano, M.J.; Bugalho de Almeida, A

    2001-07-01

    The fate of respired particles in the respiratory system is inferred through the chemical characterisation of individual particles at the tracheal and bronchial mucosas, and the accumulation of toxic elements in lung alveoli and lymph nodes. The particles and tissue elemental distributions were identified and characterised using micro-PIXE elemental mapping of thin frozen sections using the ITN Nuclear Microprobe facility. Significant particle deposits are found at the distal respiratory tract. Al, Si, Ti, V, Cr, Fe, Ni, Cu and Zn are elements detected at these accumulation areas. The elemental distributions in the different cellular environments of lymph nodes vary. The major compartments for Al, Si, Ti, Fe and Cr are the phagocytic cells and capsule of lymph nodes, while V and Ni are in the cortex and paracortex medullar areas which retain more than 70% of these two elements, suggesting high solubility of the latter in the cellular milieu. The elemental mobilisation from particles or deposits to surrounding tissues at the respiratory ducts evidences patterns of diffusion and removal that are different than those for elements in the respiratory tract. Mobilisation of elements such as V, Cr and Ni is more relevant at alveoli areas where gaseous exchange takes place. The apparent high solubility of V and Ni in the respiratory tract tissue points towards a deviation of the lymphatic system filtering efficiency for these elements when compared to others.

  16. Normal variations in the isotopic composition of metabolically relevant transition metals in human blood

    Science.gov (United States)

    Van Heghe, L.; Cloquet, C.; Vanhaecke, F.

    2012-04-01

    Cu, Fe and Zn are transition metals with great catalytic, structural and regulating importance in the human body. Hence, an aberrant metabolism of these elements can have serious implications on the health of a person. It is assumed that, due to differences in isotope fractionation, the isotopic composition of these elements in whole blood of patients can be different from that in blood of healthy subjects. Therefore, isotopic analysis of the element affected by the disease can be a promising approach for early diagnosis. A method for isotopic analysis of Cu, Fe and Zn in human whole blood was developed. The simultaneous chromatographic isolation of these elements and the conditions for isotope ratio measurement via multi-collector ICP - mass spectrometry (MC-ICP-MS) were optimized. So far, only whole blood of supposedly healthy volunteers (reference population) was analyzed. Results for Fe confirmed the known differences in isotopic composition between male and female blood. It is also shown that other parameters can have influence as well, e.g., the isotopic composition of Zn seems to be governed by the diet.

  17. Elemental composition of normal primary tooth enamel analyzed with XRMA and SIMS.

    Science.gov (United States)

    Sabel, Nina; Dietz, Wolfram; Lundgren, Ted; Nietzsche, Sandor; Odelius, Hans; Rythén, Marianne; Rizell, Sara; Robertson, Agneta; Norén, Jörgen G; Klingberg, Gunilla

    2009-01-01

    There is an interest to analyze the chemical composition of enamel in teeth from patients with different developmental disorders or syndromes and evaluate possible differences compared to normal composition. For this purpose, it is essential to have reference material. The aim of this study was to, by means of X-ray micro analyses (XRMA) and secondary ion mass spectrometry (SIMS), present concentration gradients for C, O, P and Ca and F, Na, Mg, Cl, K and Sr in normal enamel of primary teeth from healthy individuals. 36 exfoliated primary teeth from 36 healthy children were collected, sectioned, and analyzed in the enamel and dentin with X-ray micro analyses for the content of C, O, P and Ca and F, Na MgCl, K and Sr. This study has supplied reference data for C, O, P and Ca in enamel in primary teeth from healthy subjects. No statistically significant differences in the elemental composition were found between incisors and molars.The ratio Ca/P is in concordance with other studies. Some elements have shown statistically significant differences between different levels of measurement. These results may be used as reference values for research on the chemical composition of enamel and dentin in primary teeth from patients with different conditions and/or syndromes.

  18. Finite element reduction strategy for composite sandwich plates with viscoelastic layers

    Directory of Open Access Journals (Sweden)

    Adriana Amaro Diacenco

    2013-04-01

    Full Text Available Composite materials have been regarded as a convenient strategy in various types of engineering systems such as aeronautical and space structures, as well as architecture and light industry products due to their advantages over the traditional engineering materials, such as their high strength/stiffness relation characteristics and their anti-corrosion properties. This paper is devoted to the finite element modeling of composite laminated structures incorporating viscoelastic materials to the problem of vibration attenuation. However, the typically high dimension of large finite element models of composite structures incorporating viscoelastic materials makes the numerical processes sometimes unfeasible. Within this context, emphasis is placed on a general condensation strategy specially adapted for the case of viscoelastically damped structures, in which a constant (frequency- and temperature-independent reduction basis to be enriched by static residues associated to the applied loads and the viscoelastic forces is used. After presenting the theoretical foundations, the numerical applications of composite plates treated by viscoelastic materials are addressed, and the main features of the methodology are discussed.

  19. Finite element reduction strategy for composite sandwich plates with viscoelastic layers

    Directory of Open Access Journals (Sweden)

    Adriana Amaro Diacenco

    2012-01-01

    Full Text Available Composite materials have been regarded as a convenient strategy in various types of engineering systems such as aeronautical and space structures, as well as architecture and light industry products due to their advantages over the traditional engineering materials, such as their high strength/stiffness relation characteristics and their anti-corrosion properties. This paper is devoted to the finite element modeling of composite laminated structures incorporating viscoelastic materials to the problem of vibration attenuation. However, the typically high dimension of large finite element models of composite structures incorporating viscoelastic materials makes the numerical processes sometimes unfeasible. Within this context, emphasis is placed on a general condensation strategy specially adapted for the case of viscoelastically damped structures, in which a constant (frequency- and temperature-independent reduction basis to be enriched by static residues associated to the applied loads and the viscoelastic forces is used. After presenting the theoretical foundations, the numerical applications of composite plates treated by viscoelastic materials are addressed, and the main features of the methodology are discussed.

  20. Effect of duct obstruction on structure, elemental composition, and function of rat submandibular glands

    Energy Technology Data Exchange (ETDEWEB)

    Sagstroem, S.S.; Sagulin, G.B.; Roomans, G.M. (Univ. of Uppsala (Sweden))

    1989-06-01

    Obstruction of salivary glands occurs in association with a number of pathological conditions. It has been suggested that the major changes found in the salivary glands of patients with cystic fibrosis are due to obstruction of the excretory duct by viscous mucus. In the present study, the effect of excretory duct obstruction on structure, elemental composition and function of rat submandibular gland was investigated. Obstruction was effected by infusion of a fast-hardening protein emulsion in the main excretory duct. After 1 week, and more pronounced after 2 weeks of obstruction the number of granular duct cells had decreased in the obstructed gland. X-ray microanalysis showed an increase in Mg, Ca and K, and a decrease in Na levels in the acinar cells, compared to normal glands. The contralateral glands apparently underwent compensatory hypertrophy and showed a similar pattern of changes in elemental composition. The composition of pilocarpine-induced submandibular saliva was neither in the obstructed nor in the contralateral gland significantly different from that in control glands. However, the flow rate was somewhat lower. Hence, increase in cellular Ca levels in submandibular gland acinar cells in cystic fibrosis could be secondary to duct obstruction, but the present study does not support the hypothesis that duct obstruction would result in changes in the composition of saliva.

  1. MULTILAYERED PLATE ELEMENTS WITH NODE-DEPENDENT KINEMATICS FOR THE ANALYSIS OF COMPOSITE AND SANDWICH STRUCTURES

    Directory of Open Access Journals (Sweden)

    Stefano Valvano

    2017-04-01

    Full Text Available In this paper a new plate finite element (FE for the analysis of composite and sandwich plates is proposed. By making use of the node-variable plate theory assumptions, the new finite element allows for a simultaneous analysis of different subregions of the problem domain with different kinematics and accuracy, in a global/local sense. In particular higher-order theories with an Equivalent-Single-Layer (ESL approach are simultaneously used with advanced Layer-Wise (LW models. As a consequence, the computational costs can be reduced drastically by assuming refined theories only in those zones/nodes of the structural domain where the resulting strain and stress states present a complex distribution. On the contrary, computationally cheaper, low-order kinematic assumptions can be used in the remaining parts of the plate where a localized detailed analysis is not necessary. The primary advantage of the present variable-kinematics element and related global/local approach is that no ad-hoc techniques and mathematical artifices are required to mix the fields coming from two different and kinematically incompatible adjacent elements, because the plate structural theory varies within the finite element itself. In other words, the structural theory of the plate element is a property of the FE node in this present approach, and the continuity between two adjacent elements is ensured by adopting the same kinematics at the interface nodes. According to the Unified Formulation by Carrera, the through-the-thickness unknowns are described by Taylor polynomial expansions with ESL approach and by Legendre polynomials with LW approach. Furthermore, the Mixed Interpolated Tensorial Components (MITC method is employed to contrast the shear locking phenomenon. Several numerical investigations are carried out to validate and demonstrate the accuracy and efficiency of the present plate element, including comparison with various closed-form and FE solutions from the

  2. Influence of Finite Element Size in Residual Strength Prediction of Composite Structures

    Science.gov (United States)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Karayev, Kazbek Z.; Nordman, Paul S.; Razi, Hamid

    2012-01-01

    The sensitivity of failure load to the element size used in a progressive failure analysis (PFA) of carbon composite center notched laminates is evaluated. The sensitivity study employs a PFA methodology previously developed by the authors consisting of Hashin-Rotem intra-laminar fiber and matrix failure criteria and a complete stress degradation scheme for damage simulation. The approach is implemented with a user defined subroutine in the ABAQUS/Explicit finite element package. The effect of element size near the notch tips on residual strength predictions was assessed for a brittle failure mode with a parametric study that included three laminates of varying material system, thickness and stacking sequence. The study resulted in the selection of an element size of 0.09 in. X 0.09 in., which was later used for predicting crack paths and failure loads in sandwich panels and monolithic laminated panels. Comparison of predicted crack paths and failure loads for these panels agreed well with experimental observations. Additionally, the element size vs. normalized failure load relationship, determined in the parametric study, was used to evaluate strength-scaling factors for three different element sizes. The failure loads predicted with all three element sizes provided converged failure loads with respect to that corresponding with the 0.09 in. X 0.09 in. element size. Though preliminary in nature, the strength-scaling concept has the potential to greatly reduce the computational time required for PFA and can enable the analysis of large scale structural components where failure is dominated by fiber failure in tension.

  3. Effect of alloying elements on mechanical properties in Cu-15%Cr in-situ composites

    Institute of Scientific and Technical Information of China (English)

    H. G. Suzukit; J. Ma; K. Mihara; S. Sakai; S. Sun

    2004-01-01

    The effects of alloying elements on the mechanical properties as well as electrical conductivity in Cu-15 %Cr(mass fraction) in-situ composites were systematically studied and high strength and high electrical conductive Cu base in-situ composites have been developed. The best combination is the addition of 0.1% to 0.2% Zr, Ti, or Sn in Cu 15 %Cr in-situ composite, thermomechanical treatment to refine the microstructure and optimizing the precipitation of second phase. The strength is controlled by high density of dislocations in the Cu matrix, the lamellar spacing of the second phase, and the fine Cr precipitates. The aging treatment to reduce solute atoms has a beneficial effect on the increase of electrical conductivity. The addition of Zr, or Ti of about 0.15% to 0.2% promotes the precipitation of Cr particles.

  4. Modeling of the mechanical behavior of fiber-reinforced ceramic composites using finite element method (FEM

    Directory of Open Access Journals (Sweden)

    Dimitrijević M.M.

    2014-01-01

    Full Text Available Modeling of the mechanical behavior of fiber-reinforced ceramic matrix composites (CMC is presented by the example of Al2O3 fibers in an alumina based matrix. The starting point of the modeling is a substructure (elementary cell which includes on a micromechanical scale the statistical properties of the fiber, matrix and fiber-matrix interface and their interactions. The numerical evaluation of the model is accomplished by means of the finite element method. The numerical results of calculating the elastic modulus of the composite dependance on the quantity of the fibers added and porosity was compared to experimental values of specimens having the same composition. [Projekat Ministarstva nauke Republike Srbije, br. ON174004 i TVH to project III45012

  5. Compositional analysis of multi-element magnetic nanoparticles with a combined NMR and TEM approach

    Science.gov (United States)

    Gellesch, Markus; Hammerath, Franziska; Süß, Vicky; Haft, Marcel; Hampel, Silke; Wurmehl, Sabine; Büchner, Bernd

    2017-09-01

    The increasing interest in nanoscale materials goes hand in hand with the challenge to reliably characterize the chemical compositions and structural features of nanosized objects in order to relate those to their physical properties. Despite efforts, the analysis of the chemical composition of individual multi-element nanoparticles remains challenging—from the technical point of view as well as from the point of view of measurement statistics. Here, we demonstrate that zero-field solid-state nuclear magnetic resonance (NMR) complements local, single particle transmission electron microscopy (TEM) studies with information on a large assembly of chemically complex nanoparticles. The combination of both experimental techniques gives information on the local composition and structure and provides an excellent measurement statistic through the corresponding NMR ensemble measurement. This analytical approach is applicable to many kinds of magnetic materials and therefore may prove very versatile in the future research of particulate magnetic nanomaterials.

  6. Multiwalled carbon nanotube/polydimethylsiloxane composite films as high performance flexible electric heating elements

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jing; Jeong, Young Gyu, E-mail: ygjeong@cnu.ac.kr [Department of Advanced Organic Materials and Textile System Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2014-08-04

    High performance elastomeric electric heating elements were prepared by incorporating various contents of pristine multiwalled carbon nanotube (MWCNT) in polydimethylsiloxane (PDMS) matrix by using an efficient solution-casting and curing technique. The pristine MWCNTs were identified to be uniformly dispersed in the PDMS matrix and the electrical percolation of MWCNTs was evaluated to be at ∼0.27 wt. %, where the electrical resistivity of the MWCNT/PDMS composite films dropped remarkably. Accordingly, the composite films with higher MWCNT contents above 0.3 wt. % exhibit excellent electric heating performance in terms of temperature response rapidity and electric energy efficiency at constant applied voltages. In addition, the composite films, which were thermally stable up to 250 °C, showed excellent heating-cooling cyclic performance, which was associated with operational stability in actual electric heating applications.

  7. Finite Element Model Characterization Of Nano-Composite Thermal And Environmental Barrier Coatings

    Science.gov (United States)

    Yamada, Yoshiki; Zhu, Dongming

    2011-01-01

    Thermal and environmental barrier coatings have been applied for protecting Si based ceramic matrix composite components from high temperature environment in advanced gas turbine engines. It has been found that the delamination and lifetime of T/EBC systems generally depend on the initiation and propagation of surface cracks induced by the axial mechanical load in addition to severe thermal loads. In order to prevent T/EBC systems from surface cracking and subsequent delamination due to mechanical and thermal stresses, T/EBC systems reinforced with nano-composite architectures have showed promise to improve mechanical properties and provide a potential crack shielding mechanism such as crack bridging. In this study, a finite element model (FEM) was established to understand the potential beneficial effects of nano-composites systems such as SiC nanotube-reinforced oxide T/EBC systems.

  8. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE–RBS

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Z. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Zhang, K. [School of History and Culture, Sichuan University, Chengdu 610064 (China); Xia, C.D.; Liu, M.T.; Zhu, J.J. [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); An, Z., E-mail: anzhu@scu.edu.cn [Key Laboratory of Radiation Physics and Technology of Ministry of Education, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064 (China); Bai, B., E-mail: baibin@scu.edu.cn [School of History and Culture, Sichuan University, Chengdu 610064 (China)

    2015-03-01

    Highlights: •We analyzed 61 unearthed porcelain shards in Yuan Dynasty by PIXE–RBS. •An electron gun was installed to solve the electric charge accumulations. •The factor analysis was performed for the element compositions. •The “exotic group” porcelain samples unearthed were produced locally. -- Abstract: A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271–1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB{sub 6} crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907–960 A.D.) had been

  9. Elemental composition of a deep sediment core from Lake Stocksjoen in the Forsmark area

    Energy Technology Data Exchange (ETDEWEB)

    Stroemgren, Maarten [Umeaa Univ. (Sweden). Dept. of Ecology and Environmental Sciences; Brunberg, Anna-Kristina [Uppsala Univ. (Sweden). Dept. of Ecology and Evolution/Limnology

    2006-10-15

    A deep sediment core was taken from Lake Stocksjoen, situated within the Forsmark site investigation area. The 55 cm long sediment core, representing the entire history of the lake (approx 430 years) was sliced in 5 cm portions and analysed for various chemical elements, using ICP-MS technique. In total, 54 different elements - classified as main elements, heavy metals and trace elements - were analysed. In general terms, three different patterns of stratigraphy were derived from all the analysed elements. Calcium, manganese, lead and mercury occurred in highest concentrations in the upper sediments (<30 cm depth). Phosphorus, zinc, cadmium, antimony, tin and strontium occurred in more even proportions throughout the sediment core. All the other elements were substantially reduced in the upper parts (<30 cm) compared to the deeper parts of the sediment core. Metals that are considered as airborne pollutants were found in low or moderate concentrations. This is in concert with other investigations of pollutants that have been performed in the Forsmark area. The sediment of Lake Stocksjoen is highly organic, and has been so during the entire history of the lake. Much of the organic Material seems to be refractory and less susceptible for mineralisation and respiration during the prevailing environmental conditions. This corresponds well with the characteristic gelatinous cyanophycee gyttja found in the lower parts of the sediment core. Although speculative, the pronounced changes in elemental composition of the sediment at 30 cm depth may correspond to the final isolation of the lake from the Baltic Sea, which occurred approximately 230 years ago. The deeper parts (below 30 cm depth) thus may represent the time period with regular intrusions of brackish water into the lake basin. One important factor governing the environmental conditions and the resulting elemental composition of the sediment is the unusually thick 'microbial mat', which is characteristic

  10. Human Robotic Systems (HRS): Extreme Terrain Mobility Element

    Data.gov (United States)

    National Aeronautics and Space Administration — During 2014, the Extreme Terrain Mobility project element is developing five technologies:Exoskeleton Development for ISS EvaluationExtreme Terrain Mobility...

  11. Surface chemical composition of human maxillary first premolar as assessed by X-ray photoelectron spectroscopy (XPS)

    Energy Technology Data Exchange (ETDEWEB)

    Lou, Leo [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta (Canada); Nelson, Alan E. [Department of Chemical and Materials Engineering, University of Alberta (Canada)], E-mail: aenelson@dow.com; Heo, Giseon [Department of Statistics, Department of Dentistry, University of Alberta (Canada); Major, Paul W. [Orthodontic Graduate Program, Faculty of Medicine and Dentistry, University of Alberta (Canada)

    2008-08-30

    The surface chemical composition of dental enamel has been postulated as a contributing factor in the variation of bond strength of brackets bonded to teeth, and hence, the probability of bracket failure during orthodontic treatment. This study systematically investigated the chemical composition of 98 bonding surfaces of human maxillary premolars using X-ray photoelectron spectroscopy (XPS) to ascertain compositional differences between right and left first premolars. The major elements detected in all samples were calcium, phosphorus, oxygen, nitrogen and carbon. Surface compositions were highly variable between samples and several elements were found to be highly correlated. No statistical significant difference in the chemical composition of the maxillary right and left first premolars was found (p > 0.05). Knowledge of the chemical composition of enamel surfaces will facilitate future studies that relate this information to the variations in dental enamel bond strength.

  12. On the surface elemental composition of non-corroded and corroded dental ceramic materials in vitro.

    Science.gov (United States)

    Milleding, P; Karlsson, S; Nyborg, L

    2003-06-01

    Dental ceramics are traditionally looked upon as inert materials. As many are glass phased, it may be hypothesized that they will be subjected to glass corrosion in aqueous environments. The aim of the study was therefore to analyze the surface elemental composition of glass-phased and all-crystalline ceramics, before and after low- and high-intensity, in vitro corrosion (milli-Q-water at 37+/-2 degrees C for 18 h and 4% acetic acid at 80+/-2 degrees C for 18 h, respectively). The analysis of the surface elemental composition was performed using ESCA. The hypothesis was confirmed. After high-intensity corrosion, the complete wash out of alkali ions, alkaline-earth ions and elemental alumina was found, leaving behind a surface totally dominated by silica. The all-crystalline ceramics, densely sintered alumina and yttria-partially stabilized tetragonal zirconia, displayed only minor surface changes, even after high-intensity corrosion. In comparison to the corrosion testing in acid, the corrosion process in milli-Q-water did not produce different results in principle, except for the lower magnitude of the depletion of alkali ions and the virtually unchanged level of elemental alumina. Unexpectedly, no substantial difference in surface degradation was found between the glass ceramic and the ordinary porcelain-fused-to-metal ceramic or between ceramics of higher sintering temperature and those of low or ultra-low sintering temperature. The composition and microstructure alone did not appear to provide a full explanation for the inter-individual differences in surface corrosion when exposed to comparable environmental conditions.

  13. How Trace Element Levels of Public Drinking Water Affect Body Composition in Turkey.

    Science.gov (United States)

    Cetin, Ihsan; Nalbantcilar, Mahmut Tahir; Tosun, Kezban; Nazik, Aydan

    2017-02-01

    Since waterborne minerals appear in ionic form and are readily absorbed by the gastrointestinal tract, drinking water could be a crucial source of mineral intake. However, no comprehensive research has yet determined how trace elements in drinking water relate to body composition. We aimed to assess the relationship between clinically important trace elements in public drinking water and body composition in average, overweight and obese individuals in Turkey. The study's population consisted of 423 participants: 143 overweight, 138 obese and 142 healthy control individuals, grouped according to clinical cutoff points of body mass index (BMI). We measured levels of lithium (Li), nickel (Ni), lead (Pb), silicon (Si), tin (Sn), strontium (Sr), boron (B), aluminium (Al), barium (Ba) and rubidium (Rb) in samples from wells of municipal water by using inductively coupled plasma mass spectrometry. We gauged all the participants' body composition measurements with a BC-418 body composition analyser. In all the participants, body weight values showed significant positive correlations with Ni levels in drinking water, as did BMI values with Al levels and percentage of obesity with Ni, Si and B levels. In particular, Ni levels showed significant positive correlations with the basal metabolic rate, activity calories, and total activity of participants. Giving findings showing correlations between obesity-related parameters and Al, Si, B and Ni content in drinking water, we hope that these associations will be clarified with further studies including cellular, experimental and clinical studies. Hence, medical practitioners must be aware of trace element levels in drinking water for overweight and obese patients.

  14. Human body composition models and methodology : theory and experiment

    NARCIS (Netherlands)

    Wang, Z.M.

    1997-01-01


    The study of human body composition is a branch of human biology which focuses on the in vivo quantification of body components, the quantitative relationships between components, and the quantitative changes in these components related to various influencing factors.

  15. A comparison of human elements and nonhuman elements in private health care settings: customers' perceptions and expectations.

    Science.gov (United States)

    Mohd Suki, Norazah; Chwee Lian, Jennifer Chiam; Suki, Norbayah Mohd

    2009-01-01

    In today's highly competitive health care environment, many private health care settings are now looking into customer service indicators to learn customers' perceptions and determine whether they are meeting customers' expectations in order to ensure that their customers are satisfied with the services. This research paper aims to investigate whether the human elements were more important than the nonhuman elements in private health care settings. We used the internationally renowned SERVQUAL five-dimension model plus three additional dimensions-courtesy, communication, and understanding of customers of the human element-when evaluating health care services. A total of 191 respondents from three private health care settings in the Klang Valley region of Malaysia were investigated. Descriptive statistics were calculated by the Statistical Package for Social Sciences (SPSS) computer program, version 15. Interestingly, the results suggested that customers nowadays have very high expectations especially when it comes to the treatment they are receiving. Overall, the research indicated that the human elements were more important than the nonhuman element in private health care settings. Hospital management should look further to improve on areas that have been highlighted. Implications for management practice and directions for future research are discussed.

  16. Meso-damage modelling of polymer based particulate composites using finite element technique

    Science.gov (United States)

    Tsui, Chi Pong

    To develop a new particulate polymer composite (PPC) with desired mechanical properties is usually accomplished by an experimental trial-and-error approach. A new technique, which predicts the damage mechanism and its effects on the mechanical properties of PPC, has been proposed. This meso-mechanical modelling technique, which offers a means to bridge the micro-damage mechanism and the macro-structural behaviour, has been implemented in a finite element code. A three-dimensional finite element meso-cell model has been designed and constructed to simulate the damage mechanism of PPC. The meso-cell model consists of a micro-particle, an interface, and a matrix. The initiation of the particle/polymer matrix debonding process has been predicted on the basis of a tensile criterion. By considering the meso-cell model as a representative volume element (RVE), the effects of damage on the macro-structural constitutive behaviour of PPC have been determined. An experimental investigation has been made on glass beads (GB) reinforced polyphenylene oxides (PPO) for verification of the meso-cell model and the meso-mechanical finite element technique. The predicted constitutive relation has been found to be in good agreement with the experimental results. The results of the in-situ microscopic test also verify the correctness of the meso-cell model. The application of the meso-mechanical finite element modelling technique has been extended to a macro-structural analysis to simulate the response an engineering structure made of PPC under a static load. In the simulation, a damage variable has been defined in terms of the computational results of the cell model in meso-scale. Hence, the damage-coupled constitutive relation of the GB/PPO composite could be derived. A user-defined subroutine VUMAT in FORTRAN language describing the damage-coupled constitutive behaviour has then been incorporated into the ABAQUS finite element code. On a macro-scale, the ABAQUS finite element code

  17. Stress Concentration Study of Laminated Composite with Multiple Holes by Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Anand.A

    2016-10-01

    Full Text Available A “Composite” is considered as one material when two or more different materials combined together to create superior material. A composite laminate is a composite with combination of layers. They have great applications in many engineering domains like civil, marine, aerospace, biomedical etc. because of their excellent properties like low weight, better mechanical properties and ease of handling and low cost of production. The practical applications of composites enables that the composite structures usually consist cutouts in it in order to get the required design. Thus it is essential to study the behaviour of composites with multiple holes with respect to different applications in order to provide structural stability and to attain better design and mechanical Properties. This work presents Analytical and Finite Element Analysis of rectangular plate with and without multiple circular cut-outs of various sizes. The work is checked for deformation and stress obtained for various loads .The material considered was Glass/Epoxy laminate. The deformation and stress distribution for various loads is analysed by Ansys software. The specimens used are plate without hole, plate with 3 holes of 5mm each, plate with 6mm holes, plate with 8mm holes and plate with 10mm holes. The analytical and numerical results are compared in Stress - Strain curves and Load - Deformation curves and found that both are in good agreement

  18. Modelling of polypropylene fibre-matrix composites using finite element analysis

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Polypropylene (PP fibre-matrix composites previously prepared and studied experimentally were modelled using finite element analysis (FEA in this work. FEA confirmed that fibre content and composition controlled stress distribution in all-PP composites. The stress concentration at the fibre-matrix interface became greater with less fibre content. Variations in fibre composition were more significant in higher stress regions of the composites. When fibre modulus increased, the stress concentration at the fibres decreased and the shear stress at the fibre-matrix interface became more intense. The ratio between matrix modulus and fibre modulus was important, as was the interfacial stress in reducing premature interfacial failure and increasing mechanical properties. The model demonstrated that with low fibre concentration, there were insufficient fibres to distribute the applied stress. Under these conditions the matrix yielded when the applied stress reached the matrix yield stress, resulting in increased fibre axial stress. When the fibre content was high, there was matrix depletion and stress transfer was inefficient. The predictions of the FEA model were consistent with experimental and published data.

  19. A case study of elemental and structural composition of dental calculus during several stages of maturation using SRXRF.

    Science.gov (United States)

    Abraham, J; Grenón, M; Sánchez, H J; Pérez, C; Barrea, R

    2005-12-01

    This work presents a study of elemental composition and preponderant structure of human dental calculus, as they mature in the mouth for a period of 1 year. The synchrotron radiation X-ray fluorescence technique using a white beam was employed as an analytical method. The set of samples were extracted from different dental elements of the same subject, who did not require any other clinical care. By means of analyzing the Ca/P molar ratio an estimation of the main crystallographic structure was attained, by simple comparison with stoichiometric values of the several crystalline structures that compose the calculus. The results showed a slowly progressive transformation of the initial crystalline structures (brushite) into more stable structures (hydroxyapatite), passing through octacalcium phosphate and whitlockite. The concentrations of mayor components (Ca and P) as a function of time followed a sigmoid curve. The analysis of trace element concentrations versus time indicated a null or small correlation of concentration values with the kinetics of the crystallization process.

  20. Elemental Composition and Geochemical Characteristics of Iron-Manganese Nodules in Main Soils of China

    Institute of Scientific and Technical Information of China (English)

    TAN Wen-Feng; LIU Fan; LI Yong-Hua; HU Hong-Qing; HUANG Qiao-Yun

    2006-01-01

    Elemental composition and geochemical characteristics of iron-manganese nodules from nine main soils in China were studied by chemical and multivariate statistical analyses to better understand the reactions and functions of ironmanganese nodules in soils and sediment. Compared to the corresponding soils, Mn, Ba, Cd, Co and Pb had strong accumulation, Ni had moderate accumulation, while Ca, Cu, Fe, Na, P, Sr and Zn accumulated to a minor degree in the iron-manganese nodules. In contrast, Si, Al, K, Mg and Ti were reduced in the iron-manganese nodules. The contents of Ba, Cd, Co, Cu, Ni, Pb and Zn were positively and significantly correlated with that of MnO2 in the iron-manganese nodules, while the contents of Cr, Cu, Ni, Pb and Zn were positively and significantly correlated with that of Fe2O3 in soils. Based on a principle component analysis, the elements of iron-manganese nodules were divided into four groups: 1)Mn, Ba, Cd, Co, Cu, Li, Ni, Pb and Zn that were associated with Mn oxides, 2) Fe, Cr and P that were associated with Fe oxides, 3) Si, K, and Mg that were included in the elemental composition of phyllosilicate, and 4) Ca, Na, Al and Ti that existed in todorokite, birnessite, lithiophorite and phyllosilicate. It was suggested that accumulation, mineralization and specific adsorption were involved in the formation processes of soil iron-manganese nodules.

  1. Stochastic finite element method for random harmonic analysis of composite plates with uncertain modal damping parameters

    Science.gov (United States)

    Sepahvand, K.

    2017-07-01

    Damping parameters of fiber-reinforced composite possess significant uncertainty due to the structural complexity of such materials. Considering the parameters as random variables, this paper uses the generalized polynomial chaos (gPC) expansion to capture the uncertainty in the damping and frequency response function of composite plate structures. A spectral stochastic finite element formulation for damped vibration analysis of laminate plates is employed. Experimental modal data for samples of plates is used to identify and realize the range and probability distributions of uncertain damping parameters. The constructed gPC expansions for the uncertain parameters are used as inputs to a deterministic finite element model to realize random frequency responses on a few numbers of collocation points generated in random space. The realizations then are employed to estimate the unknown deterministic functions of the gPC expansion approximating the responses. Employing modal superposition method to solve harmonic analysis problem yields an efficient sparse gPC expansion representing the responses. The results show while the responses are influenced by the damping uncertainties at the mid and high frequency ranges, the impact in low frequency modes can be safely ignored. Utilizing a few random collocation points, the method indicates also a very good agreement compared to the sampling-based Monte Carlo simulations with large number of realizations. As the deterministic finite element model serves as black-box solver, the procedure can be efficiently adopted to complex structural systems with uncertain parameters in terms of computational time.

  2. Effects of gamma radiation on the Elemental composition of the flour moth Ephestia kuhniella z

    OpenAIRE

    Souka, Soheir; Ashry, Hoda; Abdu, R. M.; El Sawaf, Bahira; Abbasy, Somaya

    1994-01-01

    The effect of gamma radiation on the elemental composition of larvae, pupae and adults stages of the flour moth Ephestia kuhniella after irradiation of eggs to the sterilizing dose was studied. The elemental composition as well as the concentration level of elements detected in the different stages are summarized in the following: تناول البحث دراسة العناصر الرئيسية والنادرة في الأطوار المختلفة لحشرة فراشة الدقيق وتأثير الجرعة المعقمة من أشعة جاما على هذه العناصر . وذلك بهدف تفهم دور هذه ال...

  3. Dynamic Finite Element Analysis of Extensional-Torsional Coupled Vibration in Nonuniform Composite Beams

    Science.gov (United States)

    Hashemi, Seyed M.; Roach, Andrew

    2011-12-01

    The application of a Dynamic Finite Element (DFE) technique to the extensional-torsional free vibration analysis of nonuniform composite beams, in the absence of flexural coupling, is presented. The proposed method is a fusion of the Galerkin weighted residual formulation and the Dynamic Stiffness Matrix (DSM) method, where the basis functions of approximation space are assumed to be the closed form solutions of the differential equations governing uncoupled extensional and torsional vibrations of the beam. The use of resulting dynamic trigonometric interpolation (shape) functions leads to a frequency dependent stiffness matrix, representing both mass and stiffness properties of the beam element. Assembly of the element matrices and the application of the boundary conditions then leads to a frequency dependent nonlinear eigenproblem, which is solved to evaluate the system natural frequencies and modes. Two illustrative examples of uniform and tapered cantilevered, Circumferentially Uniform Stiffness ( CUS), hollow, composite beams are presented. The influence of ply fibre-angle on the natural frequencies is also studied. The correctness of the theory and the superiority of the proposed DFE over the contrasting DSM and conventional FEM methods are confirmed by the published results and numerical checks. The discussion of results is followed by some concluding remarks.

  4. A finite element analysis of a 3D auxetic textile structure for composite reinforcement

    Science.gov (United States)

    Ge, Zhaoyang; Hu, Hong; Liu, Yanping

    2013-08-01

    This paper reports the finite element analysis of an innovative 3D auxetic textile structure consisting of three yarn systems (weft, warp and stitch yarns). Different from conventional 3D textile structures, the proposed structure exhibits an auxetic behaviour under compression and can be used as a reinforcement to manufacture auxetic composites. The geometry of the structure is first described. Then a 3D finite element model is established using ANSYS software and validated by the experimental results. The deformation process of the structure at different compression strains is demonstrated, and the validated finite element model is finally used to simulate the auxetic behaviour of the structure with different structural parameters and yarn properties. The results show that the auxetic behaviour of the proposed structure increases with increasing compression strain, and all the structural parameters and yarn properties have significant effects on the auxetic behaviour of the structure. It is expected that the study could provide a better understanding of 3D auxetic textile structures and could promote their application in auxetic composites.

  5. Using trace element content and lead isotopic composition to assess sources of PM in Tijuana, Mexico

    Science.gov (United States)

    Salcedo, D.; Castro, T.; Bernal, J. P.; Almanza-Veloz, V.; Zavala, M.; González-Castillo, E.; Saavedra, M. I.; Perez-Arvízu, O.; Díaz-Trujillo, G. C.; Molina, L. T.

    2016-05-01

    PM2.5 samples were collected at two urban sites (Parque Morelos (PQM) and CECyTE (CEC)) in Tijuana during the Cal-Mex campaign from May 24 to June 5, 2010. Concentration of trace elements (Mg, Al, Ti, V, Mn, Fe, Co, Ni, Zn, Cu, Ga, As, Se, Rb, Sr, Mo, Cd, Sn, Sb, Ba, La, Ce, and Pb), and Pb isotopic composition were determined in order to study the sources of PM impacting each site. Other chemical analysis (gravimetric, elemental and organic carbon (EC/OC), and polycyclic aromatic hydrocarbons (PAHs)), were also performed. Finally, back-trajectories were calculated to facilitate the interpretation of the chemical data. Trace elements results show that CEC is a receptor site affected by mixed regional sources: sea salt, mineral, urban, and industrial. On the other hand, PQM seems to be impacted mainly by local sources. In particular, Pb at CEC is of anthropogenic, as well as crustal origin. This conclusion is supported by the lead isotopic composition, whose values are consistent with a combination of lead extracted from US mines, and lead from bedrocks in the Mexican Sierras. Some of the time variability observed can be explained using the back-trajectories.

  6. Microstructure and performance of multiwalled carbon nanotube/m-aramid composite films as electric heating elements.

    Science.gov (United States)

    Jeong, Young Gyu; Jeon, Gil Woo

    2013-07-24

    We report microstructure of thermomechanically stable multiwalled carbon nanotube (MWCNT)/poly(m-phenylene isophthalamide) (m-aramid) composite films containing 0.0-10.0 wt % MWCNTs and their performance as electric heating elements. FE-SEM images show that the MWCNTs are well dispersed in the composite films and are wrapped with m-aramid chains and that the interfacial thickness of m-aramid wrapped MWCNTs decreases with the MWCNT content. The electrical resistivity of films varies from ∼10(13) Ω cm for the neat m-aramid to ∼10(0) Ω cm of the film with 10.0 wt % MWCNT owing to the formation of a conductive three-dimensional network of MWCNTs. Accordingly, the performance of MWCNT/m-aramid films as electric heating elements is strongly dependent on MWCNT content as well as applied voltage. For the composite film with 10.0 wt % MWCNT, a maximum temperature of ∼176 °C is attained even at a low applied voltage of 10 V. The excellent performance such as rapid temperature response and high electric power efficiency at given applied voltages is found to be related with the microstructural features of the MWCNT/m-aramid films.

  7. Finite Element Simulation of Low Velocity Impact Damage on an Aeronautical Carbon Composite Structure

    Science.gov (United States)

    Lemanle Sanga, Roger Pierre; Garnier, Christian; Pantalé, Olivier

    2016-06-01

    Low velocity barely visible impact damage (BVID) in laminated carbon composite structures has a major importance for aeronautical industries. This contribution leads with the development of finite element models to simulate the initiation and the propagation of internal damage inside a carbon composite structure due by a low velocity impact. Composite plates made from liquid resin infusion process (LRI) have been subjected to low energy impacts (around 25 J) using a drop weight machine. In the experimental procedure, the internal damage is evaluated using an infrared thermographic camera while the indentation depth of the face is measured by optical measurement technique. In a first time we developed a robust model using homogenised shells based on degenerated tri-dimensional brick elements and in a second time we decided to modelize the whole stacking sequence of homogeneous layers and cohesive interlaminar interfaces in order to compare and validate the obtained results. Both layer and interface damage initiation and propagation models based on the Hashin and the Benzeggagh-Kenane criteria have been used for the numerical simulations. Comparison of numerical results and experiments has shown the accuracy of the proposed models.

  8. Geometrically-linear and nonlinear analysis of linear viscoelastic composites using the finite element method

    Science.gov (United States)

    Hammerand, Daniel C.

    Over the past several decades, the use of composite materials has grown considerably. Typically, fiber-reinforced polymer-matrix composites are modeled as being linear elastic. However, it is well-known that polymers are viscoelastic in nature. Furthermore, the analysis of complex structures requires a numerical approach such as the finite element method. In the present work, a triangular flat shell element for linear elastic composites is extended to model linear viscoelastic composites. Although polymers are usually modeled as being incompressible, here they are modeled as compressible. Furthermore, the macroscopic constitutive properties for fiber-reinforced composites are assumed to be known and are not determined using the matrix and fiber properties along with the fiber volume fraction. Hygrothermo-rheologically simple materials are considered for which a change in the hygrothermal environment results in a horizontal shifting of the relaxation moduli curves on a log time scale, in addition to the usual hygrothermal loads. Both the temperature and moisture are taken to be prescribed. Hence, the heat energy generated by the viscoelastic deformations is not considered. When the deformations and rotations are small under an applied load history, the usual engineering stress and strain measures can be used and the time history of a viscoelastic deformation process is determined using the original geometry of the structure. If, however, sufficiently large loads are applied, the deflections and rotations will be large leading to changes in the structural stiffness characteristics and possibly the internal loads carried throughout the structure. Hence, in such a case, nonlinear effects must be taken into account and the appropriate stress and strain measures must be used. Although a geometrically-nonlinear finite element code could always be used to compute geometrically-linear deformation processes, it is inefficient to use such a code for small deformations, due to

  9. Human immunodeficiency virus type 2 long terminal repeat: analysis of regulatory elements.

    OpenAIRE

    Arya, S. K.; Gallo, R C

    1988-01-01

    The long terminal repeats (LTRs) of the human immunodeficiency virus type 2 (HIV-2) and a related simian immunodeficiency virus (SIVmac) contain cis-acting positive regulatory elements upstream and the major transactivator gene (tat) response element and a possible negative regulatory element downstream of the transcriptional initiation site. The tat response element of HIV-2 and of SIVmac was more complex than that of HIV-1. Two structurally similar subelements within the HIV-2 tat response ...

  10. Human Robotic Systems (HRS): Controlling Robots over Time Delay Element

    Data.gov (United States)

    National Aeronautics and Space Administration — This element involves the development of software that enables easier commanding of a wide range of NASA relevant robots through the Robot Application Programming...

  11. Human Robotic Systems (HRS): Robotic ISRU Acquisition Element

    Data.gov (United States)

    National Aeronautics and Space Administration — During 2014, the Robotic ISRU Resource Acquisition project element will develop two technologies:Exploration Ground Data Systems (xGDS)Sample Acquisition on...

  12. Comparison of Damage Path Predictions for Composite Laminates by Explicit and Standard Finite Element Analysis Tools

    Science.gov (United States)

    Bogert, Philip B.; Satyanarayana, Arunkumar; Chunchu, Prasad B.

    2006-01-01

    Splitting, ultimate failure load and the damage path in center notched composite specimens subjected to in-plane tension loading are predicted using progressive failure analysis methodology. A 2-D Hashin-Rotem failure criterion is used in determining intra-laminar fiber and matrix failures. This progressive failure methodology has been implemented in the Abaqus/Explicit and Abaqus/Standard finite element codes through user written subroutines "VUMAT" and "USDFLD" respectively. A 2-D finite element model is used for predicting the intra-laminar damages. Analysis results obtained from the Abaqus/Explicit and Abaqus/Standard code show good agreement with experimental results. The importance of modeling delamination in progressive failure analysis methodology is recognized for future studies. The use of an explicit integration dynamics code for simple specimen geometry and static loading establishes a foundation for future analyses where complex loading and nonlinear dynamic interactions of damage and structure will necessitate it.

  13. An efficient finite element with layerwise mechanics for smart piezoelectric composite and sandwich shallow shells

    Science.gov (United States)

    Yasin, M. Yaqoob; Kapuria, S.

    2014-01-01

    In this work, we present a new efficient four-node finite element for shallow multilayered piezoelectric shells, considering layerwise mechanics and electromechanical coupling. The laminate mechanics is based on the zigzag theory that has only seven kinematic degrees of freedom per node. The normal deformation of the piezoelectric layers under the electric field is accounted for without introducing any additional deflection variables. A consistent quadratic variation of the electric potential across the piezoelectric layers with the provision of satisfying the equipotential condition of electroded surfaces is adopted. The performance of the new element is demonstrated for the static response under mechanical and electric potential loads, and for free vibration response of smart shells under different boundary conditions. The predictions are found to be very close to the three dimensional piezoelasticity solutions for hybrid shells made of not only single-material composite substrates, but also sandwich substrates with a soft core for which the equivalent single layer (ESL) theories perform very badly.

  14. Free material stiffness design of laminated composite structures using commercial finite element analysis codes

    DEFF Research Database (Denmark)

    Henrichsen, Søren Randrup; Lindgaard, Esben; Lund, Erik

    2015-01-01

    In this work optimum stiffness design of laminated composite structures is performed using the commercially available programs ANSYS and MATLAB. Within these programs a Free Material Optimization algorithm is implemented based on an optimality condition and a heuristic update scheme. The heuristic...... update scheme is needed because commercially available finite element analysis software is used. When using a commercial finite element analysis code it is not straight forward to implement a computationally efficient gradient based optimization algorithm. Examples considered in this work are a clamped......-clamped 2D plate loaded in two load cases and a point loaded six layered 3D double curved corner hinged shell. The first example displays the effect of varying the size of patches having the same parametrization, and the second illustrates the benefit of using a layered free material parametrization...

  15. Special hybrid stress element for stress analyses around circular cutouts in laminated composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A 3-dimensional hybrid stress element with a traction-free cylindrical surface based on amodified complementary energy principle has been derived for efficient and accurate analysis of stressconcentration around circular cutouts in thin to thick laminated composites. New expressions of sixstress components are developed by using three stress-functions in cylindrical co-ordinates, so that thehomogeneous equilibrium equations, the interlayer surface transverse-stresses and the traction-freeboundary condition on the cylindrical surface are satisfied exactly, while the interelement traction conti-nuity has been relaxed via the Lagrange multiplier method. Transverse-shear deformation effects areincorporated in each layer with displacement continuity enforced along interlayer surface. Selected ex-amples are used to demonstrate the efficiency and accuracy of the present special element.

  16. Elemental stoichiometry and compositions of weevil larvae and two acorn hosts under natural phosphorus variation

    Science.gov (United States)

    Ji, Huawei; Du, Baoming; Liu, Chunjiang

    2017-04-01

    To understand how different trophic organisms in a parasite food chain adapt to the differences in soil nutrient conditions, we investigated stoichiometric variation and homeostasis of multiple elements in two acorn trees, Quercus variabilis and Quercus acutissima, and their parasite weevil larvae (Curculio davidi Fairmaire) at phosphorus (P)-deficient and P-rich sites in subtropical China where P-rich ores are scattered among dominant P-deficient soils. Results showed that elemental stoichiometry and compositions of both acorns and weevil larvae differed significantly between P-deficient and P-rich sites (p plants and animals to P loading, a worldwide issue from excess release of P into the environment.

  17. Detecting changes in the nutritional value and elemental composition of transgenic sorghum grain

    Energy Technology Data Exchange (ETDEWEB)

    Ndimba, R., E-mail: rminnis@tlabs.ac.za [iThemba LABS, National Research Foundation (South Africa); Institute for Plant Biotechnology, University of Stellenbosch, Matieland (South Africa); Grootboom, A.W.; Mehlo, L.; Mkhonza, N.L. [Council for Scientific and Industrial Research (CSIR) Biosciences, Pretoria (South Africa); Kossmann, J. [Institute for Plant Biotechnology, University of Stellenbosch, Matieland (South Africa); Barnabas, A.D.; Mtshali, C. [iThemba LABS, National Research Foundation (South Africa); Pineda-Vargas, C. [iThemba LABS, National Research Foundation (South Africa); Faculty of Health and Wellness Sciences, CPUT, Bellville (South Africa)

    2015-11-15

    We have previously demonstrated that poor digestibility in sorghum can be addressed by using RNA interference (RNAi) to suppress kafirin synthesis. The approach resulted in a twofold improvement in overall protein digestibility levels. In the present study, the effect of this targeted kafirin suppression on other grain quality parameters was investigated. Several significant changes in the proximate composition, amino acid profile and the bulk mineral content were detected. Importantly, the most limiting amino acid, lysine, was significantly increased in the transgenic grains by up to 39%; whilst mineral elements in the bulk, such as sulphur (S) and zinc (Zn) were reduced by up to 15.8% and 21% respectively. Elemental mapping of the grain tissue, using micro-PIXE, demonstrated a significant decrease in Zn (>75%), which was localised to the outer endosperm region, whilst TEM revealed important changes to the protein body morphology of the transgenic grains.

  18. Detecting changes in the nutritional value and elemental composition of transgenic sorghum grain

    Science.gov (United States)

    Ndimba, R.; Grootboom, A. W.; Mehlo, L.; Mkhonza, N. L.; Kossmann, J.; Barnabas, A. D.; Mtshali, C.; Pineda-Vargas, C.

    2015-11-01

    We have previously demonstrated that poor digestibility in sorghum can be addressed by using RNA interference (RNAi) to suppress kafirin synthesis. The approach resulted in a twofold improvement in overall protein digestibility levels. In the present study, the effect of this targeted kafirin suppression on other grain quality parameters was investigated. Several significant changes in the proximate composition, amino acid profile and the bulk mineral content were detected. Importantly, the most limiting amino acid, lysine, was significantly increased in the transgenic grains by up to 39%; whilst mineral elements in the bulk, such as sulphur (S) and zinc (Zn) were reduced by up to 15.8% and 21% respectively. Elemental mapping of the grain tissue, using micro-PIXE, demonstrated a significant decrease in Zn (>75%), which was localised to the outer endosperm region, whilst TEM revealed important changes to the protein body morphology of the transgenic grains.

  19. Finite element investigations on the microstructure of fibre-reinforced composites

    Directory of Open Access Journals (Sweden)

    2008-09-01

    Full Text Available The effect of residual stress due to the curing process on damage evolution in unidirectional (UD fibre-reinforced polymer-matrix composites under longitudinal and transverse loading has been investigated using a three-dimensional micromechanical representative volume element (RVE model with a hexagonal packing geometry and the finite element method. Residual stress has been determined by considering two contributions: volume shrinkage of matrix resin from the crosslink polymerization during isothermal curing and thermal contraction of both resin and fibre as a result of cooling from the curing temperature to room temperature. To examine the effect of residual stress on failure, a study based on different failure criteria and a stiffness degradation technique has been used for damage analysis of the RVE subjected to mechanical loading after curing for a range of fibre volume fractions. Predicted damage initiation and evolution are clearly influenced by the presence of residual stress.

  20. Finite Element Model for Failure Study of Two-Dimensional Triaxially Braided Composite

    Science.gov (United States)

    Li, Xuetao; Binienda, Wieslaw K.; Goldberg, Robert K.

    2010-01-01

    A new three-dimensional finite element model of two-dimensional triaxially braided composites is presented in this paper. This meso-scale modeling technique is used to examine and predict the deformation and damage observed in tests of straight sided specimens. A unit cell based approach is used to take into account the braiding architecture as well as the mechanical properties of the fiber tows, the matrix and the fiber tow-matrix interface. A 0 deg / plus or minus 60 deg. braiding configuration has been investigated by conducting static finite element analyses. Failure initiation and progressive degradation has been simulated in the fiber tows by use of the Hashin failure criteria and a damage evolution law. The fiber tow-matrix interface was modeled by using a cohesive zone approach to capture any fiber-matrix debonding. By comparing the analytical results to those obtained experimentally, the applicability of the developed model was assessed and the failure process was investigated.

  1. Apollo 16 impact-melt splashes - Petrography and major-element composition

    Science.gov (United States)

    See, Thomas H.; Horz, Friedrich; Morris, Richard V.

    1986-11-01

    Petrographic and major-element analyses are applied to 50 Apollo 16 impact-melt splash (IMS) samples in order to determine their origin and assess the nature of the subregolith source. The macroscopic analyses reveal that the IMSs exhibit a glassy appearance, but the textures range from holohyaline to hyalopilitic. Schlieren-rich glasses dominate the holohyaline areas, and the crystalline areas are mainly spherulitic. It is observed that most IMSs contain feldspathic monomineralic and lithic clasts and no regolithic materials. It is detected that the chemistry of most IMSs is not like the local regolith and appears to represent varied mixtures of VHA impact-melt breccias and anorthosite; the host rocks are mainly dimict breccias. It is concluded that the Cayley Formation is a polymict deposit composed of VHA impact-melt breccias and anorthosites. Tables revealing the macroscopic characteristics of the IMSs and the major-element composition of IMSs and various host rock are presented.

  2. Bioagent Sample Matching using Elemental Composition Data: an Approach to Validation

    Energy Technology Data Exchange (ETDEWEB)

    Velsko, S P

    2006-04-21

    Sample matching is a fundamental capability that can have high probative value in a forensic context if proper validation studies are performed. In this report we discuss the potential utility of using the elemental composition of two bioagent samples to decide if they were produced in the same batch, or by the same process. Using guidance from the recent NRC study of bullet lead analysis and other sources, we develop a basic likelihood ratio framework for evaluating the evidentiary weight of elemental analysis data for sample matching. We define an objective metric for comparing two samples, and propose a method for constructing an unbiased population of test samples. We illustrate the basic methodology with some existing data on dry Bacillus thuringiensis preparations, and outline a comprehensive plan for experimental validation of this approach.

  3. PHYTOCHEMICAL SCREENING AND MINERAL ELEMENTS COMPOSITION OF CORDYCEPS SINENSIS AND ITS BASED PRODUCT (ESULIN

    Directory of Open Access Journals (Sweden)

    Farah Atiqah Ab Rahman

    2015-12-01

    Full Text Available Screening of phytochemical and mineral elements composition of Cordyceps sinensis and its based product, Esulin were carried out in order to provide a basis for further research on the therapeutic value of these herbs. The results of both aqueous extracts positively showed the presence of several bioactive compounds like alkaloids, saponins, tannins, and flavonoids. However, terpenoids only present in the aqueous extract of Esulin. In addition, the levels of copper, zinc, cadmium, ferum, lead and nickel of both extracts were below the maximum permissible level suggested by World Health Organization (1989 & Malaysian Food Law (1985. The presence of phytochemical components and mineral elements in the aqueous extract of Cordyceps sinensis and Esulin might contribute to their therapeutic applications in medicinal practices.

  4. A SIMPLE FINITE ELEMENT FOR NON-LINEAR ANALYSIS OF COMPOSITE PLATES

    Directory of Open Access Journals (Sweden)

    V.B. Tungikar

    2011-06-01

    Full Text Available Finite Element Analysis for geometrically nonlinear behaviour of laminated composite plates is presented andcompared with the reported investigations. However structural non-linearity is encountered in certain cases andneeds attention. A higher order displacement field that accounts for transverse shear effects under geometricnonlinear condition is employed in the formulation of a four node, rectangular, element with thirteen degrees offreedom per node. First order Zigzag terms have been included in displacement field for improvement in theresponse. Von Karman strain approach is considered in the present analysis. Incremental Pica iterative scheme isused to solve resulting nonlinear equilibrium equations. The formulation demonstrates its excellence in theperformance for predicting response at various lay ups and plies conditions.

  5. A Remote Laser-mass Spectrometer for Determination of Elemental Composition

    Science.gov (United States)

    Deyoung, R. J.; Situ, W.

    1993-01-01

    Determination of the elemental composition of lunar, asteroid, and planetary surfaces is a major concern for science and resource utilization of space. The science associated with the development of a satellite or lunar rover laser-mass spectrometer instrument is presented here. The instrument would include a pulsed laser with sufficient energy to create a plasma on a remote surface. Ions ejected from this plasma travel back to the spacecraft or rover, where they are analyzed by a time-of-flight mass spectrometer, giving the elemental and isotope composition. This concept is based on the LIMA-D instrument on board the former Soviet Union Phobos-88 spacecraft sent to Mars. A laser-mass spectrometer placed on a rover or satellite would substantially improve the data return over alternative techniques. The spatial resolution would be centimeters, and a complete mass spectrum could be achieved in one laser shot. An experiment is described that demonstrates these features. A 400 mj Nd:YAG laser is focused, to an intensity of 10(exp 11) w/sq cm, onto a Al, Ag, Cu, Ge, or lunar simulant target. A plasma forms from which ions are ejected. Some of these ions travel down an 18-m evacuated flight tube to a microchannel plate detector. Alternatively, the ions are captured by an ion trap where they are stored until pulsed into a 1-m time-of-flight mass spectrometer, giving the elemental composition of the remote surface. A television camera monitors the plasma plume shape, and a photodiode monitors the temporal plasma emission . With this system, ions of Al, Ag, Cu, Ge, and lunar simulant have been detected at 18 m. The mass spectrum from the ion trap and 1-m time-of-flight tube will be presented.

  6. Comparison of the elemental composition of office document paper: evidence in a homicide case.

    Science.gov (United States)

    Spence, Lindsay D; Francis, Rod B; Tinggi, Ujang

    2002-05-01

    Fraudulent substitution of a page within a multiple page document such as a will or business contract, the counterfeit manufacture of paper banknotes, and linking ransom or extortion notes have all been the focus of criminal investigations at one time or another. In a recent homicide investigation, document examiners were requested to compare a threatening letter received by a business partner of the deceased with paper samples seized under warrant from a suspect's house. Through a quantitative elemental analysis of the concentrations of nine elements (Na, Mg, Al, Mn, Sr, Y, Ba, La, and Ce) within the questioned and specimen documents, determined by inductively coupled plasma-mass spectrometry (ICP-MS), it was concluded that (i) the paper of the threatening letter originated from a different source to that of the paper seized from the suspect's house and (ii) all six pages of paper seized from the suspect's house originated from the same source. This discrimination of paper is presented as both a statistical t-test analysis (99.9% confidence limit) as well as construction of an elemental fingerprint for individual replicates within the questioned and specimen sample populations. This is the first reported use of the comparison of the elemental composition of document paper, determined by ICP-MS, to assist in a criminal investigation.

  7. Total elemental composition of soils contaminated with wastewater irrigation by combining IBA techniques

    Energy Technology Data Exchange (ETDEWEB)

    Huerta, L. E-mail: lazaro@fisica.unam.mx; Contreras-Valadez, R.; Palacios-Mayorga, S.; Miranda, J.; Calva-Vasquez, G

    2002-04-01

    The purpose of this work was to obtain the total elemental composition of agricultural soils irrigated with well water and wastewater. The studied area is located in the Valle del Mezquital in Hidalgo State, Mexico. The studied soils were collected, every two months during one year. Particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA) were applied for elemental analysis. PIXE analyses gave elemental contents of major and trace elements (Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Br, Rb, Sr, Y, Zr, and Pb). Total concentrations of Na, Mg, C, N and O were obtained by RBS and NRA. PIXE analyses were carried out with 2 MeV proton beams, RBS with 2 MeV helium ions, while NRA was applied with a 1.2 MeV deuterium beam. Results indicated that heavy metal total concentrations exceed the critical soil total concentrations according to environmental regulations.

  8. Multi-elemental composition and physical properties of honey samples from Malaysia.

    Science.gov (United States)

    Chua, Lee Suan; Abdul-Rahaman, Norul-Liza; Sarmidi, Mohamad Roji; Aziz, Ramlan

    2012-12-01

    The elemental profiles of six honey samples from Malaysia had been constructed using the data obtained from both ICP-AES and ICP-MS. Potassium and sodium were the most abundant minerals covering from 69.3-78.6% and 14.1-28.7%, respectively. The ratio of potassium to sodium was more than one. Even though the minerals and trace elements composition varied dependent on the type of honey samples, there was no statistically significant difference between the analysed honey samples, namely tualang, gelam, acacia and a few forest honeys based on two-factor ANOVA and cluster analysis. The total element content of honey samples were strongly correlated with the electrical conductivity, but only have moderate correlation with the ash content and honey colour based on the regression analysis. PCA result on the available elemental data from worldwide honeys, including honey samples from Malaysia revealed that potassium and sodium were the mineral markers to distinguish honey origin. Both tualang and gelam honey samples from Malaysia have close mineral profile with sesame honeys from Egypt and multifloral honeys from India, whereas forest honeys Malaysia were near to avocado honeys from Spain and multifloral honeys from India. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Probabilistic Design of Hollow Airfoil Composite Structure by Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Mr. Sachin M. Shinde

    2014-04-01

    Full Text Available This study represents simulation of Airfoil composite beam by using Monte Carlo method. A three dimensional static analysis of large displacement type has been carried out. Finite element analysis of NACA0012 airfoil composite structure has been carried out and uncertainty in bending stress is analyzed. Bending stress was objective function. Chord length , beam length ,elastic modulus in XY,YZ,XZ and shear modulus of epoxy graphite in XY,YZ,XZ, ply angle and ply thickness of airfoil section, force are varied within effective range and their effect on bending stress has been analyzed. In order to validate the results, one loop of simulation is benchmarked from results in literature. Ultimately, best set of probabilistic design variable is proposed to reduce bending stress under static loading condition.

  10. Probabilistic Design of Hollow Circular Composite Structure by using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Mr. Sachin M. Shinde

    2014-10-01

    Full Text Available This study represents simulation of hollow circular composite beam by using Monte Carlo method. A three dimensional static analysis of large displacement type has been carried out. Finite element analysis of hollow circular composite structure has been carried out and uncertainty in bending stress is analyzed. Bending stress was objective function. Beam length, beam radius, elastic modulus, shear modulus and Poisson ratio of epoxy graphite, ply angles of hollow circular section and force are randomly varied within effective range and their effect on bending stress has been analyzed. In order to validate the results, one loop of simulation is benchmarked from results in literature. Ultimately, best set of probabilistic design variable is proposed to reduce bending stress under static loading condition.

  11. Finite element modeling and analysis of piezo-integrated composite structures under large applied electric fields

    Science.gov (United States)

    Rao, M. N.; Tarun, S.; Schmidt, R.; Schröder, K.-U.

    2016-05-01

    In this article, we focus on static finite element (FE) simulation of piezoelectric laminated composite plates and shells, considering the nonlinear constitutive behavior of piezoelectric materials under large applied electric fields. Under the assumptions of small strains and large electric fields, the second-order nonlinear constitutive equations are used in the variational principle approach, to develop a nonlinear FE model. Numerical simulations are performed to study the effect of material nonlinearity for piezoelectric bimorph and laminated composite plates as well as cylindrical shells. In comparison to the experimental investigations existing in the literature, the results predicted by the present model agree very well. The importance of the present nonlinear model is highlighted especially in large applied electric fields, and it is shown that the difference between the results simulated by linear and nonlinear constitutive FE models cannot be omitted.

  12. Homogenized Finite Element Analysis on Effective Elastoplastic Mechanical Behaviors of Composite with Imperfect Interfaces

    Directory of Open Access Journals (Sweden)

    Wu-Gui Jiang

    2014-12-01

    Full Text Available A three-dimensional (3D representative volume element (RVE model was developed for analyzing effective mechanical behavior of fiber-reinforced ceramic matrix composites with imperfect interfaces. In the model, the fiber is assumed to be perfectly elastic until its tensile strength, and the ceramic material is modeled by an elasto-plastic Drucker-Prager constitutive law. The RVE model is then used to study the elastic properties and the tensile strength of composites with imperfect interfaces and validated through experiments. The imperfect interfaces between the fiber and the matrix are taken into account by introducing some cohesive contact surfaces. The influences of the interface on the elastic constants and the tensile strengths are examined through these interface models.

  13. Homogenized finite element analysis on effective elastoplastic mechanical behaviors of composite with imperfect interfaces.

    Science.gov (United States)

    Jiang, Wu-Gui; Zhong, Ren-Zhi; Qin, Qing H; Tong, Yong-Gang

    2014-12-16

    A three-dimensional (3D) representative volume element (RVE) model was developed for analyzing effective mechanical behavior of fiber-reinforced ceramic matrix composites with imperfect interfaces. In the model, the fiber is assumed to be perfectly elastic until its tensile strength, and the ceramic material is modeled by an elasto-plastic Drucker-Prager constitutive law. The RVE model is then used to study the elastic properties and the tensile strength of composites with imperfect interfaces and validated through experiments. The imperfect interfaces between the fiber and the matrix are taken into account by introducing some cohesive contact surfaces. The influences of the interface on the elastic constants and the tensile strengths are examined through these interface models.

  14. Finite element modeling and fabrication of an SMA-SMP shape memory composite actuator

    Science.gov (United States)

    Souri, Mohammad

    Shape memory alloys and polymers have been extensively researched recently because of their unique ability to recover large deformations. Shape memory polymers (SMPs) are able to recover large deformations compared to shape memory alloys (SMAs), although SMAs have higher strength and are able to generate more stress during recovery. This project focuses on procedure for fabrication and Finite Element Modeling (FEM) of a shape memory composite actuator. First, SMP was characterized to reveal its mechanical properties. Specifically, glass transition temperature, the effects of temperature and strain rate on compressive response and recovery properties of shape memory polymer were studied. Then, shape memory properties of a NiTi wire, including transformation temperatures and stress generation, were investigated. SMC actuator was fabricated by using epoxy based SMP and NiTi SMA wire. Experimental tests confirmed the reversible behavior of fabricated shape memory composites. (Abstract shortened by ProQuest.).

  15. Comparative study of the nutritional composition and toxic elements of farmed and wild Chanodichthys mongolicus

    Science.gov (United States)

    Jiang, Haifeng; Cheng, Xiaofei; Geng, Longwu; Tang, Shizhan; Tong, Guangxiang; Xu, Wei

    2016-09-01

    Information of the difference in quality between farmed and wild fish is central to better ensuring fish products produced in aquaculture meet regulatory and consumer requirements. Proximate composition, amino acid and fatty acid profiles, and toxic elements contents of farmed and wild C. mongolicus were established and compared. Significantly higher crude protein content while lower moisture content in farmed fish compared to wild fish were observed (P values, the ratios of TEAA/TAA (39.84%-40.33%) were comparable to 40% and TEAA / TNEAA (66.22%-67.60%) were above 60%. Fatty acid profiles in both farmed and wild C. mongolicus were dominated by monounsaturated fatty acid (MUFA), with farmed fish contained much more MUFA content compared to wild counterpart (P nutritional quality of farmed C. mongolicus was inferior to their wild counterpart with respect to fatty acids nutrition, and therefore further studies should focus on the improving C. mongolicus diet in order to enhance the overall nutritional composition.

  16. Comparative study of the nutritional composition and toxic elements of farmed and wild Chanodichthys mongolicus

    Science.gov (United States)

    Jiang, Haifeng; Cheng, Xiaofei; Geng, Longwu; Tang, Shizhan; Tong, Guangxiang; Xu, Wei

    2017-07-01

    Information of the difference in quality between farmed and wild fish is central to better ensuring fish products produced in aquaculture meet regulatory and consumer requirements. Proximate composition, amino acid and fatty acid profiles, and toxic elements contents of farmed and wild Chanodichthys mongolicus were established and compared. Significantly higher crude protein content while lower moisture content in farmed fish compared to wild fish were observed ( Pcontent compared to wild counterpart ( Pelement levels (As, Cd, Pb and Hg) in comparison with wild fish, and both were far lower than the established limit standard. In conclusion, our results suggest that the nutritional quality of farmed C. mongolicus was inferior to their wild counterpart with respect to fatty acids nutrition, and therefore further studies should focus on the improving C. mongolicus diet in order to enhance the overall nutritional composition.

  17. submitter Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions

    CERN Document Server

    Praplan, A P; Bianchi, F; Rissanen, M P; Ehn, M; Jokinen, T; Junninen, H; Adamov, A; Amorim, A; Dommen, J; Duplissy, J; Hakala, J; Hansel, A; Heinritzi, M; Kangasluoma, J; Kirkby, J; Krapf, M; Kürten, A; Lehtipalo, K; Riccobono, F; Rondo, L; Sarnela, N; Simon, M; Tomé, A; Tröstl, J; Winkler, P M; Williamson, C; Ye, P; Curtius, J; Baltensperger, U; Donahue, N M; Kulmala, M; Worsnop, D R

    2015-01-01

    This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1) pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH) scavenger) and (2) OH oxidation (initiated by nitrous acid (HONO) photolysis by ultraviolet light) in the absence of ozone. We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF) mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate). Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition o...

  18. Effect of Rare Earths on Composition and Activities of Rare Earth Elements Binding Glycoprotein in Tea

    Institute of Scientific and Technical Information of China (English)

    汪东风; 李俊; 赵贵文; 王常红; 魏正贵; 尹明

    2001-01-01

    The effects of spraying rare earths(RE) on composition and activities of tea polysaccharide were measured by inductively coupled plasma mass spectrometry (ICP-MS), gas chromatography(GC), amino acid analyzer and animal models. The results show that there are rare earth elements binding glycoprotein in tea (REE-TGP). The effects of RE on composition and content of saccharides in REE-TGP are not obvious. The contents of Hypro and Ser in REE-TGP are evidently enhanced in comparison with that in control (not treated with rare earth), but the content of Glu is smaller than that from control. The content of La in REE-TGP from the tea garden sprayed rare earth is 193% higher than that in control. REE-TGP declines content of blood sugar in mice and enhances immunization of rat, which are very evident when the animals are treated by REE-TGP from the tea garden sprayed RE.

  19. Evaluation of Solid Modeling Software for Finite Element Analysis of Woven Ceramic Matrix Composites

    Science.gov (United States)

    Nemeth, Noel N.; Mital, Subodh; Lang, Jerry

    2010-01-01

    Three computer programs, used for the purpose of generating 3-D finite element models of the Repeating Unit Cell (RUC) of a textile, were examined for suitability to model woven Ceramic Matrix Composites (CMCs). The programs evaluated were the open-source available TexGen, the commercially available WiseTex, and the proprietary Composite Material Evaluator (COMATE). A five-harness-satin (5HS) weave for a melt-infiltrated (MI) silicon carbide matrix and silicon carbide fiber was selected as an example problem and the programs were tested for their ability to generate a finite element model of the RUC. The programs were also evaluated for ease-of-use and capability, particularly for the capability to introduce various defect types such as porosity, ply shifting, and nesting of a laminate. Overall, it was found that TexGen and WiseTex were useful for generating solid models of the tow geometry; however, there was a lack of consistency in generating well-conditioned finite element meshes of the tows and matrix. TexGen and WiseTex were both capable of allowing collective and individual shifting of tows within a ply and WiseTex also had a ply nesting capability. TexGen and WiseTex were sufficiently userfriendly and both included a Graphical User Interface (GUI). COMATE was satisfactory in generating a 5HS finite element mesh of an idealized weave geometry but COMATE lacked a GUI and was limited to only 5HS and 8HS weaves compared to the larger amount of weave selections available with TexGen and WiseTex.

  20. Olivine Major and Trace Element Compositions in Southern Payenia Basalts, Argentina

    DEFF Research Database (Denmark)

    Søager, Nina; Portnyagin, Maxim; Hoernle, Kaj;

    2015-01-01

    Olivine major and trace element compositions from 12 basalts from the southern Payenia volcanic province in Argentina have been analyzed by electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The olivines have high Fe/Mn and low Ca/Fe and many fall at the end...... by subduction-zone fluids and/or melts. The increasing contributions from the pyroxene-rich source in the southern Payenia basalts are correlated with an increasing Fe-enrichment, which caused the olivines to have lower forsterite contents at a given Ni content. Al-in-olivine crystallization temperatures...

  1. Identification of parameters of cohesive elements for modeling of adhesively bonded joints of epoxy composites

    Directory of Open Access Journals (Sweden)

    Kottner R.

    2013-12-01

    Full Text Available Adhesively bonded joints can be numerically simulated using the cohesive crack model. The critical strain energy release rate and the critical opening displacement are the parameters which must be known when cohesive elements in MSC.Marc software are used. In this work, the parameters of two industrial adhesives Hunstman Araldite 2021 and Gurit Spabond 345 for bonding of epoxy composites are identified. Double Cantilever Beam (DCB and End Notched Flexure (ENF test data were used for the identification. The critical opening displacements were identified using an optimization algorithm where the tests and their numerical simulations were compared.

  2. Superficial composition in binary solid solutions A(B): Drastic effect of pure element surface tensions

    Science.gov (United States)

    Rolland, A.; Aufray, B.

    1985-10-01

    This paper deals with a comparative study of surface segragation of Pb and Ni respectively from Ag(Pb)(111) and Ag(Ni)(111) solid solutions. A high level of segregation of the solute is observed for both systems characterized by very low solute solubility. However, the superficial composition strongly depends on the relative surface tensions of the pure elements: the solute atoms are strictly on superficial sites when γ solute is smaller than γ solvent; in contrast uppermost layer consists purely of solvent when γ solute is greater than γ solvent. Two schematic distributions in close proximity to the surface are proposed in the last case.

  3. Hybrid Finite Element Analysis of Free Edge Effect in Symmetric Composite Laminates

    Science.gov (United States)

    1983-06-01

    ANALYSIS OF FREE EDGE EFFECT IN L AUTHOR(S 61102F S.W. Lee237B J.J. Rhiu S.C. Won,, I ~ 7. PENOAMnG ORGANIZATION NAME(S) AND ADORES4 S) L. PERFORMING...ANALYSIS OF FREE EDGE EFFECT IN SYMMETRIC COMPOSITE LAMINATES S. W. Lee I 3. Phi S. C. Wong Department of Aerospace Engineering University of Maryland...collocation method. In this report, we present an efficient hybrid finite element method for analysis of interlaminar stress or free edge effect in

  4. Electrochemical sensor for dopamine based on a novel graphene-molecular imprinted polymers composite recognition element

    DEFF Research Database (Denmark)

    Mao, Yan; Bao, Yu; Gan, Shiyu

    2011-01-01

    A novel composite of graphene sheets/Congo red-molecular imprinted polymers (GSCR-MIPs) was synthesized through free radical polymerization (FRP) and applied as a molecular recognition element to construct dopamine (DA) electrochemical sensor. The template molecules (DA) were firstly absorbed...... at the GSCR surface due to their excellent affinity, and subsequently, selective copolymerization of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) was further achieved at the GSCR surface. Potential scanning was presented to extract DA molecules from the imprinted polymers film...

  5. Estimation of Local Delamination Buckling in Orthotropic Composite Plates Using Kirchhoff Plate Finite Elements

    Directory of Open Access Journals (Sweden)

    Zoltán Juhász

    2015-01-01

    Full Text Available We analyse the buckling process of composite plates with through-the-width delamination and straight crack front applying uniaxial compression. We are focusing on the mixed mode buckling case, where the non-uniform distribution of the in-plane forces controls the occurence of the buckling of the delaminated layers. For the analysis, semi-discrete finite elements will be derived based on the Lèvy-type method. The method of harmonic balance is used for taking into account the force distribution that is generally non uniform in-plane.

  6. Composition and Dynamics of Human Mitochondrial Nucleoids

    OpenAIRE

    Garrido, Nuria; Griparic, Lorena; Jokitalo, Eija; Wartiovaara, Jorma; van der Bliek, Alexander M.; Spelbrink, Johannes N.

    2003-01-01

    The organization of multiple mitochondrial DNA (mtDNA) molecules in discrete protein-DNA complexes called nucleoids is well studied in Saccharomyces cerevisiae. Similar structures have recently been observed in human cells by the colocalization of a Twinkle-GFP fusion protein with mtDNA. However, nucleoids in mammalian cells are poorly characterized and are often thought of as relatively simple structures, despite the yeast paradigm. In this article we have used immunocytochemistry and bioche...

  7. Impact Wear Properties of Metal-Plastic Multilayer Composites Filled with Glass Fiber Treated with Rare Earth Element Surface Modifier

    Institute of Scientific and Technical Information of China (English)

    程先华; 薛玉君

    2001-01-01

    The friction and wear properties of metal-plastic multilayer composites filled with glass fiber, which is treated with rare earth element surface modifier, under impact load and dry friction conditions were investigated. Experimental results show that the metal-plastic multilayer composite filled with glass fiber exhibits excellent friction and impact wear properties when using rare earth elements as surface modifier for the surface treatment of glass fiber.

  8. Short interspersed transposable elements (SINEs) are excluded from imprinted regions in the human genome.

    Science.gov (United States)

    Greally, John M

    2002-01-08

    To test whether regions undergoing genomic imprinting have unique genomic characteristics, imprinted and nonimprinted human loci were compared for nucleotide and retroelement composition. Maternally and paternally expressed subgroups of imprinted genes were found to differ in terms of guanine and cytosine, CpG, and retroelement content, indicating a segregation into distinct genomic compartments. Imprinted regions have been normally permissive to L1 long interspersed transposable element retroposition during mammalian evolution but universally and significantly lack short interspersed transposable elements (SINEs). The primate-specific Alu SINEs, as well as the more ancient mammalian-wide interspersed repeat SINEs, are found at significantly low densities in imprinted regions. The latter paleogenomic signature indicates that the sequence characteristics of currently imprinted regions existed before the mammalian radiation. Transitions from imprinted to nonimprinted genomic regions in cis are characterized by a sharp inflection in SINE content, demonstrating that this genomic characteristic can help predict the presence and extent of regions undergoing imprinting. During primate evolution, SINE accumulation in imprinted regions occurred at a decreased rate compared with control loci. The constraint on SINE accumulation in imprinted regions may be mediated by an active selection process. This selection could be because of SINEs attracting and spreading methylation, as has been found at other loci. Methylation-induced silencing could lead to deleterious consequences at imprinted loci, where inactivation of one allele is already established, and expression is often essential for embryonic growth and survival.

  9. Regional distribution of potassium, calcium, and six trace elements in normal human brain

    Energy Technology Data Exchange (ETDEWEB)

    Duflou, H.; Maenhaut, W.; De Reuck, J. (Institute for Nuclear Sciences, Gent (Belgium))

    1989-11-01

    Eight elements (i.e. K, Ca, Mn, Fe, Cu, Zn, Se, and Rb) were measured in 50 different regions of 12 normal human brains by particle-induced X-ray emission (PIXE) analysis. The dry weight concentrations of K, Fe, Cu, Zn, Se, and Rb were consistently higher for gray than for white matter areas. The K, Zn and Se concentrations for the regions of mixed composition and, to some extent, also the Rb concentrations, were intermediate between the gray and white matter values, and they tended to decrease with decreasing neuron density. The mean dry weight concentrations of K, Ca, Zn, Se, and Rb in the various brain regions were highly correlated with the mean wet-to-dry weight ratios of these regions. For Mn, Fe, and Cu, however, such a correlation was not observed, and these elements exhibited elevated levels in several structures of the basal ganglia. For K, Fe, and Se the concentrations seemed to change with age. A hierarchical cluster analysis indicated that the structures clustered into two large groups, one comprising gray and mixed matter regions, the other white and mixed matter areas. Brain structures involved in the same physiological function or morphologically similar regions often conglomerated in a single subcluster.

  10. The association of LUR modeled PM{sub 2.5} elemental composition with personal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Montagne, Denise; Hoek, Gerard [Institute for Risk Assessment Sciences (IRAS), University of Utrecht, Utrecht (Netherlands); Nieuwenhuijsen, Mark [Center for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); Lanki, Timo; Pennanen, Arto [Department of Environmental Health, National Institute for Health and Welfare (THL), Kuopio (Finland); Portella, Meritxell [Center for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); Meliefste, Kees; Wang, Meng; Eeftens, Marloes [Institute for Risk Assessment Sciences (IRAS), University of Utrecht, Utrecht (Netherlands); Yli-Tuomi, Tarja [Department of Environmental Health, National Institute for Health and Welfare (THL), Kuopio (Finland); Cirach, Marta [Center for Research in Environmental Epidemiology (CREAL), Barcelona (Spain); Brunekreef, Bert [Institute for Risk Assessment Sciences (IRAS), University of Utrecht, Utrecht (Netherlands); Julius Center for Health Sciences and Primary Care, University Medical Center, University of Utrecht, Utrecht (Netherlands)

    2014-09-15

    Background and aims: Land use regression (LUR) models predict spatial variation of ambient concentrations, but little is known about the validity in predicting personal exposures. In this study, the association of LUR modeled concentrations of PM{sub 2.5} components with measured personal concentrations was determined. The elements of interest were copper (Cu), iron (Fe), potassium (K), nickel (Ni), sulfur (S), silicon (Si), vanadium (V) and zinc (Zn). Methods: In Helsinki (Finland), Utrecht (the Netherlands) and Barcelona (Spain) five participants from urban background, five from suburban background and five from busy street sites were selected in each city (15 participants per city). Outdoor, indoor and personal 96-hour PM{sub 2.5} samples were collected by the participants over periods of two weeks in three different seasons (winter, summer and spring/autumn) and the overall average was calculated. Elemental composition was measured by ED-XRF spectrometry. The LUR models for the average ambient concentrations of each element were developed by the ESCAPE project. Results: LUR models predicted the within-city variation of average outdoor Cu and Fe concentrations moderately well (range in R{sup 2} 27–67% for Cu and 24–54% for Fe). The outdoor concentrations of the other elements were not well predicted. The LUR modeled concentration only significantly correlated with measured personal Fe exposure in Utrecht and Ni and V in Helsinki. The LUR model predictions did not correlate with measured personal Cu exposure. After excluding observations with an indoor/outdoor ratio of > 1.5, modeled Cu outdoor concentrations correlated with indoor concentrations in Helsinki and Utrecht and personal concentrations in Utrecht. The LUR model predictions were associated with measured outdoor, indoor and personal concentrations for all elements when the data for the three cities was pooled. Conclusions: Within-city modeled variation of elemental composition of PM{sub 2.5} did not

  11. Exploring human breast milk composition by NMR-based metabolomics.

    Science.gov (United States)

    Praticò, Giulia; Capuani, Giorgio; Tomassini, Alberta; Baldassarre, Maria Elisabetta; Delfini, Maurizio; Miccheli, Alfredo

    2014-01-01

    Breast milk is a complex fluid evolutionarily adapted to satisfy the nutritional requirements of growing infants. In addition, milk biochemical and immunological components protect newborns against infective agents in the new environment. Human milk oligosaccharides, the third most abundant component of breast milk, are believed to modulate the microbiota composition, thus influencing a wide range of physiological processes of the infant. Human milk also contains a number of other bioactive compounds, the functional role of which has not yet been clearly elucidated. In this scenario, NMR-based metabolic profiling can provide a rapid characterisation of breast milk composition, thus allowing a better understanding of its nutritional properties.

  12. Composition of human excreta - a case study from Souther Thailand

    DEFF Research Database (Denmark)

    Schouw, Nanette L..; Danteravanich, S.; Mosbæk, Hans

    2002-01-01

    . In the present study the composition of human. excreta has been studied in three case study areas in Southern Thailand: Kuan Lang, Phattalung and Prik. The inhabitants of the three areas represent people of Southern Thailand by age, sex, occupation, religion and type of residence. Human excreta was collected....... Furthermore, there was no significant influence of age, sex, occupation or religion on the chemical composition. The only significant variation was that the older people excreted larger amounts of total wet matter than the younger, which could be due to a higher water intake, in order to reduce the risk...

  13. Human Research Program Human Health Countermeasures Element Nutrition Risk Standing Review Panel

    Science.gov (United States)

    Bistrian, Bruce

    2009-01-01

    The Nutrition Risk Standing Review Panel (SRP) reviewed and discussed the specific gaps and tasks for the Human Health Countermeasures (HHC) Element related to nutrition identified in the Human Research Program (HRP) Integrated Research Plan. There was general consensus that the described gaps and proposed tasks were critical to future NASA mission success. The SRP acknowledged the high scientific quality of the work currently being undertaken by the Nutritional Biochemistry group under the direction of Dr. Scott Smith. In review of the entire HRP, four new gaps were identified that complement the Element's existing research activities. Given the limitations of ground-based analogs for many of the unique physiological and metabolic alterations in space, future studies are needed to quantify nutritional factors that change during actual space flight. In addition, future tasks should seek to better evaluate the time course of physiological and metabolic alterations during flight to better predict alterations during longer duration missions. Finally, given the recent data suggesting a potential role for increased inflammatory responses during space flight, the role of inflammation needs to be explored in detail, including the development of potential countermeasures and new ground based analogs, if this possibility is confirmed.

  14. The origin of aubrites: Evidence from lithophile trace element abundances and oxygen isotope compositions

    Science.gov (United States)

    Barrat, J. A.; Greenwood, R. C.; Keil, K.; Rouget, M. L.; Boesenberg, J. S.; Zanda, B.; Franchi, I. A.

    2016-11-01

    We report the abundances of a selected set of "lithophile" trace elements (including lanthanides, actinides and high field strength elements) and high-precision oxygen isotope analyses of a comprehensive suite of aubrites. Two distinct groups of aubrites can be distinguished: (a) the main-group aubrites display flat or light-REE depleted REE patterns with variable Eu and Y anomalies; their pyroxenes are light-REE depleted and show marked negative Eu anomalies; (b) the Mount Egerton enstatites and the silicate fraction from Larned display distinctive light-REE enrichments, and high Th/Sm ratios; Mount Egerton pyroxenes have much less pronounced negative Eu anomalies than pyroxenes from the main-group aubrites. Leaching experiments were undertaken to investigate the contribution of sulfides to the whole rock budget of the main-group aubrites. Sulfides contain in most cases at least 50% of the REEs and of the actinides. Among the elements we have analyzed, those displaying the strongest lithophile behaviors are Rb, Ba, Sr and Sc. The homogeneity of the Δ17O values obtained for main-group aubrite falls [Δ17O = +0.009 ± 0.010‰ (2σ)] suggests that they originated from a single parent body whose differentiation involved an early phase of large-scale melting that may have led to the development of a magma ocean. This interpretation is at first glance in agreement with the limited variability of the shapes of the REE patterns of these aubrites. However, the trace element concentrations of their phases cannot be used to discuss this hypothesis, because their igneous trace-element signatures have been modified by subsolidus exchange. Finally, despite similar O isotopic compositions, the marked light-REE enrichments displayed by Mount Egerton and Larned suggest that they are unrelated to the main-group aubrites and probably originated from a distinct parent body.

  15. Seasonal, Inter-annual and Long Term Trends in the Element Composition of Tropical Tree Rings

    Science.gov (United States)

    Verheyden, A.; Beeckman, H.; Andre, L.

    2008-12-01

    The inorganic composition of Rhizophora mucronata wood was studied on 11 stem discs collected from two mangrove forests in Kenya. The aim of this preliminary study was to assess if elements could be used as proxies of environmental and/or anthropogenic change. Earlywood and late wood were separated and analyzed on ICP-MS and ICP-OES. A remarkable synchronicity was found between ring width and Mg/Ca and Mn/Ca ratios, both of which have been used as soil pH proxies. However, there was also a negative correlation between Ca and ring width, indicating a dilution effect at higher growth rates. The essential elements P and K were significantly higher in fast growing plantation trees, suggesting that these elements might be useful as nutrient proxies in mangrove wood. A high correlation was found between Ca and Sr in the wood, indicating that probably no differentiation is made by the tree during incorporation of these elements in the wood. Since Sr/Ca of seawater is related to salinity, we suggest that the Sr/Ca in the wood could be used as a salinity proxy for tree species growing in brackish waters. Finally, a high-resolution study was also conducted using LA-ICP-MS, which revealed a high spatial variability within one ring. This high variability was the result of different concentrations in each wood cell type analyzed. The heavy metals (Cu, Zn, Pb and Cr), as well as Ba, had highest concentrations in the fibers and lowest in the vessels. On the other hand, B, Mn, Ca, P, and Sr were highest in the rays and vessels and lowest in the fibers, while Mg was the highest in the rays, but lowest in the vessels. The implications of these results for the use of trace elements to delimit chemical ring boundaries in tropical trees will be discussed.

  16. Human Research Program Human Health Countermeasures Element Extravehicular Activity (EVA) Risk Standing Review Panel (SRP)

    Science.gov (United States)

    Norfleet, William; Harris, Bernard

    2009-01-01

    The Extravehicular Activity (EVA) Risk Standing Review Panel (SRP) was favorably impressed by the operational risk management approach taken by the Human Research Program (HRP) Integrated Research Plan (IRP) to address the stated life sciences issues. The life sciences community at the Johnson Space Center (JSC) seems to be focused on operational risk management. This approach is more likely to provide risk managers with the information they need at the time they need it. Concerning the information provided to the SRP by the EVA Physiology, Systems, and Performance Project (EPSP), it is obvious that a great deal of productive activity is under way. Evaluation of this information was hampered by the fact that it often was not organized in a fashion that reflects the "Gaps and Tasks" approach of the overall Human Health Countermeasures (HHC) effort, and that a substantial proportion of the briefing concerned subjects that, while interesting, are not part of the HHC Element (e.g., the pressurized rover presentation). Additionally, no information was provided on several of the tasks or how they related to work underway or already accomplished. This situation left the SRP having to guess at the efforts and relationship to other elements, and made it hard to easily map the EVA Project efforts currently underway, and the data collected thus far, to the gaps and tasks in the IRP. It seems that integration of the EPSP project into the HHC Element could be improved. Along these lines, we were concerned that our SRP was split off from the other participating SRPs at an early stage in the overall agenda for the meeting. In reality, the concerns of EPSP and other projects share much common ground. For example, the commonality of the concerns of the EVA and exercise physiology groups is obvious, both in terms of what reduced exercise capacity can do to EVA capability, and how the exercise performed during an EVA could contribute to an overall exercise countermeasure prescription.

  17. Archaeal community structures in the solfataric acidic hot springs with different temperatures and elemental compositions.

    Science.gov (United States)

    Satoh, Tomoko; Watanabe, Keiko; Yamamoto, Hideo; Yamamoto, Shuichi; Kurosawa, Norio

    2013-01-01

    Archaeal 16S rRNA gene compositions and environmental factors of four distinct solfataric acidic hot springs in Kirishima, Japan were compared. The four ponds were selected by differences of temperature and total dissolved elemental concentration as follows: (1) Pond-A: 93°C and 1679 mg L(-1), (2) Pond-B: 66°C and 2248 mg L(-1), (3) Pond-C: 88°C and 198 mg L(-1), and (4) Pond-D: 67°C and 340 mg L(-1). In total, 431 clones of 16S rRNA gene were classified into 26 phylotypes. In Pond-B, the archaeal diversity was the highest among the four, and the members of the order Sulfolobales were dominant. The Pond-D also showed relatively high diversity, and the most frequent group was uncultured thermoacidic spring clone group. In contrast to Pond-B and Pond-D, much less diverse archaeal clones were detected in Pond-A and Pond-C showing higher temperatures. However, dominant groups in these ponds were also different from each other. The members of the order Sulfolobales shared 89% of total clones in Pond-A, and the uncultured crenarchaeal groups shared 99% of total Pond-C clones. Therefore, species compositions and biodiversity were clearly different among the ponds showing different temperatures and dissolved elemental concentrations.

  18. Determination of elemental composition in dietary supplements by neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vitor I.; Saiki, Mitiko, E-mail: vitor.ito@outlook.com, E-mail: mitiko@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Dietary supplements intake has grown in the last years because of their potential health benefits. This supplementation is very common among athletes, elderly population and consumers that want to increase the total daily nutrient intake. Consequently, elemental composition evaluation in these supplements is of great interest due to its increasingly high consumption and the brand variety offered in the market. This study aimed to evaluate the elemental composition in three types of dietary supplements acquired in a pharmacy and drugstore in Sao Paulo city. Concentrations of As, Br, Ca, Co, Cr, Cu, Fe, K, La, Na, Sb, Sc, Se and Zn were determined in these supplements by applying neutron activation analysis (NAA) followed by a gamma ray spectrometry. from the concentrations obtained in the dietary supplement analyses, the data obtained were compared to the values presented on the product label. These comparisons indicated in general, a good agreement of the data obtained and the values of the product label depending on the supplement. From the results obtained it can be concluded that NAA is an important tool for the analysis of this type of products due to its reliability of results and its multielemental character. (author)

  19. Trace-element composition of Chicxulub crater melt rock, K/T tektites and Yucatan basement

    Science.gov (United States)

    Hildebrand, A. R.; Gregoire, D. C.; Attrep, M., Jr.; Claeys, P.; Thompson, C. M.; Boynton, W. V.

    1993-01-01

    The Cretaceous/Tertiary (K/T) boundary Chicxulub impact is the best preserved large impact in the geologic record. The Chicxulub crater has been buried with no apparent erosion of its intracrater deposits, and its ejecta blanket is known and is well preserved at hundreds of localities globally. Although most of the molten material ejected from the crater has been largely altered, a few localities still preserve tektite glass. Availability of intra- and extracrater impact products as well as plausible matches to the targeted rocks allows the comparison of compositions of the different classes of impact products to those of the impacted lithologies. Determination of trace-element compositions of the K/T tektites, Chicxulub melt rock, and the targeted Yucatan silicate basement and carbonate/evaporite lithologies have been made using instrumental neutron activation analysis (INAA) and inductively coupled plasma mass spectrometry (ICP-MS). Some sample splits were studied with both techniques to ensure that inter-laboratory variation was not significant or could be corrected. The concentration of a few major and minor elements was also checked against microprobe results. Radiochemical neutron activation analysis (RNAA) was used to determine Ir abundances in some samples.

  20. A correlation for calculating elemental composition from proximate analysis of biomass materials

    Energy Technology Data Exchange (ETDEWEB)

    Jigisha Parikh; S.A. Channiwala; G.K. Ghosal [Sarvajanik College of Engineering and Technology, Surat (India). Chemical Engineering Department

    2007-08-15

    Elemental composition of biomass is an important property, which defines the energy content and determines the clean and efficient use of the biomass materials. However, the ultimate analysis requires very expensive equipments and highly trained analysts. The proximate analysis on the other hand only requires standard laboratory equipments and can be run by any competent scientist or engineer. This work introduces a general correlation, based on proximate analysis of biomass materials, to calculate elemental composition, derived using 200 data points and validated further for additional 50 data points. The entire spectrum of solid lignocellulosic materials have been considered in the derivation of the present correlation, which is given as: C = 0.637FC + 0.455VM, H = 0.052FC + 0.062VM, O = 0.304FC + 0.476VM, where FC - 4.7-38.4% fixed carbon, VM - 57.2-90.6% volatile matter, C - 36.2-53.1% carbon, H - 4.36-8.3% hydrogen and O - 31.37-49.5% oxygen in wt% on a dry basis. The average absolute error of these correlations are 3.21%, 4.79%, 3.4% and bias error of 0.21%, -0.15% and 0.49% with respect to measured values C, H and O, respectively. The major advantage of these correlations is their capability to compute elemental components of biomass materials from the simple proximate analysis and thereby provides a useful tool for the modeling of combustion, gasification and pyrolysis processes. 32 refs., 6 figs., 2 tabs.

  1. Ultrastructure and elemental composition of the eggshell of Reeve's Pheasant (Syrmaticus reevesii)

    Institute of Scientific and Technical Information of China (English)

    CHANG Chongyan; ZHANG Zhengwang; CHEN Xiaoduan; LIU Jinying; SUN Quanhui

    2007-01-01

    The eggshell of Reeve's pheasant (Syrmaticus reevesii) collected from the Dongzhai National Nature Reserve in Henan Province,China was studied.By using scanning electron microscopy and inductively coupled plasma (ICP) spectrometry,the ultrastructure and elemental composition of the eggshell was determined.The study showed that the average thickness of the surface layer of crystals,the palisade and cone layer,and the eggshell membrane were 20.8,220.8 and 62.5 larn,respectively,accounting for 6.8%,72.6% and 20.6% of the total thickness of the eggshell.There were many vesicular holes in the palisade layer with an average diameter of 0.32±0.08 μm(n = 30).The function of these holes might be significant to air exchange.The shape of the eggshell pore on the surface layer of crystals is round or elliptical.The fracture surface of the pore is funnel-shaped.Some granules filled the upper part of the eggshell pores.The content of 21 elements in the eggshell of wild and captive Reeve's pheasants was compared and presented.It indicated that among the elements that made up the eggshell of the wild pheasant,the content of Ca,Mg,P and S was much higher,ω> 1 mg/g,with ω (Ca) being higher than 40% of the eggshell.The contents of Na,Si,Sr,K and A1 were ω = 0.1-1 mg/g,while Fe,Zn,Pb,Mn,Cu,V and Ti had lower concentrations (ω = 1-100 μg/g).The ω ofNi,Cr,Co,Se,Cd were lower than 1 μg/g.The elemental composition in the eggshell of the captive Reeve's pheasant kept in the Dongzhai National Natural Reserve was significantly different from that of the wild species,with a difference of over 20% on S,Cu,Fe,AI,Mn,Si,Sr,Se and Cr.The lower intake of Fe,Mn,Si and Sr on the one hand and the higher intake of S,Cu,Al and Cr on the other hand might be responsible for the low fertility of captive Reeve's pheasants in the Dongzhai National Nature Reserve.In order to ensure that the pheasants are receiving the proper amount of nutrition and to improve their breeding success,the amount of

  2. Oxidative damages to DNA by indoor PM10s: Their relationships with trace element compositions

    Institute of Scientific and Technical Information of China (English)

    SHAO Longyi; ZHAO Houyin; T. P. JONES; LU Senlin; L. MEROLLA

    2005-01-01

    Plasmid DNA assay and ICP-MS analysis were conducted in order to investigate the bioreactivity of inhalable particles (PM10) and the relationship between bioreactivity and trace element compositions of PM10 in Beijing air. A total of four PM10 samples were carefully selected to represent the indoor and corresponding outdoor environments: one from urban smoker's home, two from nonsmoker's homes, and the other from the outdoor. In general, the oxidative damage by indoor PM10 was slightly higher than that of outdoor. Among the four sets of samples, the PM10 from the smoker's home hada lowest TD50 (toxic dose of PM10 causing 50% DNA to damage to plasmid DNA. The ICP-MS analysis combined with the DNA assay showed that the water-soluble zinc levels had better relationship with TD50 values than other elements, implying that water-soluble zinc might play an important role in the damage of DNA. It is concluded that the PM10 in smoker' s home had the highest level of water-soluble zinc as well as the lowest TD50 ( highest bioreactivity).Iron is considered to be one of the most bioreactive elements, but it will cause little damage to plasmid DNA, probably because iron is mainly in water-insoluble state in Beijing PM10.

  3. Finite Element Analysis of Composite Hardened Walls Subjected to Blast Loads

    Directory of Open Access Journals (Sweden)

    Girum S. Urgessa

    2009-01-01

    Full Text Available Problem statement: There is currently no standard design guideline to determine the number of composites needed to retrofit masonry walls in order to withstand a given explosion. Past design approaches were mainly based on simplified single-degree-of-freedom analysis. A finite element analysis was conducted for concrete masonry walls hardened with composites and subjected to short duration blast loads. Approach: The analysis focused on displacement time history responses which form the basis for retrofit design guidelines against blast loadings. The blast was determined from 0.5 kg equivalent TNT explosive at 1.83 m stand-off distance to simulate small mailroom bombs. Two and four layered retrofitted walls were investigated. Uncertainties in the finite model analysis of walls such as pressure distributions, effect of mid height explosive bursts versus near the ground explosive bursts and variations in modulus of elasticity of the wall were presented. Results: Uniformly distributed blast loads over the retrofitted wall height produced a small difference in peak displacement results when compared to the non-uniform pressure distribution. Ground explosive burst was shown to produce a 62.7% increase in energy and a higher peak displacement response when compared to mid-height explosive burst. Conclusion: The parametric study on the variation of modulus of elasticity of concrete masonry showed no significant effect on peak displacement affirming the use of the resistance deflection contribution of the composite in retrofit designs.

  4. Fast multipole boundary element analysis of 2D viscoelastic composites with imperfect interfaces

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A fast multipole boundary element method(FMBEM)is developed for the analysis of 2D linear viscoelastic composites with imperfect viscoelastic interfaces.The transformed fast multipole formulations are established using the time domain method. To simulate the viscoelastic behavior of imperfect interfaces that are frequently encountered in practice,the Kelvin type model is introduced.The FMBEM is further improved by incorporating naturally the interaction among inclusions as well as eliminating the phenomenon of material penetration.Since all the integrals are evaluated analytically,high accuracy and fast convergence of the numerical scheme are obtained.Several numerical examples,including planar viscoelastic composites with a single inclusion or randomly distributed multi-inclusions are presented.The numerical results are compared with the developed analytical solutions,which illustrates that the proposed FMBEM is very efficient in determining the macroscopic viscoelastic behavior of the particle-reinforced composites with the presence of imperfect interfaces.The laboratory measurements of the mixture creep compliance of asphalt concrete are also compared with the prediction by the developed model.

  5. Finite element modeling of guided wave scattering at delaminations in composite panels

    Science.gov (United States)

    Murat, B. I. S.; Fromme, P.

    2016-04-01

    Carbon fiber laminate composites, consisting of layers of polymer matrix reinforced with high strength carbon fibers, are increasingly employed for aerospace structures. They offer advantages for aerospace applications, e.g., good strength to weight ratio. However, impact during the operation and servicing of the aircraft can lead to barely visible and difficult to detect damage. Depending on the severity of the impact, delaminations can occur, reducing the load carrying capacity of the structure. Efficient structural health monitoring of composite panels can be achieved using guided ultrasonic waves propagating along the structure. The guided ultrasonic wave (A0 Lamb wave mode) scattering at delaminations was modelled using full three-dimensional Finite Element (FE) simulations. The influence of the delamination size was systematically investigated from a parameter study. The angular dependency of the scattered guided wave amplitude was calculated using a baseline subtraction method. A significant influence of the delamination width on the guided wave scattering was found. The sensitivity of guided waves for the detection of barely visible impact damage in composite panels has been predicted.

  6. Finite Element Analysis of Layered Fiber Composite Structures Accounting for the Material's Microstructure and Delamination

    Science.gov (United States)

    Stier, Bertram; Simon, Jaan-Willem; Reese, Stefanie

    2015-04-01

    The present paper focuses on composite structures which consist of several layers of carbon fiber reinforced plastics (CFRP). For such layered composite structures, delamination constitutes one of the major failure modes. Predicting its initiation is essential for the design of these composites. Evaluating stress-strength relation based onset criteria requires an accurate representation of the through-the-thickness stress distribution, which can be particularly delicate in the case of shell-like structures. Thus, in this paper, a solid-shell finite element formulation is utilized which allows to incorporate a fully three-dimensional material model while still being suitable for applications involving thin structures. Moreover, locking phenomena are cured by using both the EAS and the ANS concept, and numerical efficiency is ensured through reduced integration. The proposed anisotropic material model accounts for the material's micro-structure by using the concept of structural tensors. It is validated by comparison to experimental data as well as by application to numerical examples.

  7. Finite Element Analysis of Interfacial Debonding in Copper/Diamond Composites for Thermal Management Applications.

    Science.gov (United States)

    Zain-Ul-Abdein, Muhammad; Ijaz, Hassan; Saleem, Waqas; Raza, Kabeer; Mahfouz, Abdullah Salmeen Bin; Mabrouki, Tarek

    2017-07-02

    Copper/diamond (Cu/D) composites are famous in thermal management applications for their high thermal conductivity values. They, however, offer some interface related problems like high thermal boundary resistance and excessive debonding. This paper investigates interfacial debonding in Cu/D composites subjected to steady-state and transient thermal cyclic loading. A micro-scale finite element (FE) model was developed from a SEM image of the Cu/20 vol % D composite sample. Several test cases were assumed with respect to the direction of heat flow and the boundary interactions between Cu/uncoated diamonds and Cu/Cr-coated diamonds. It was observed that the debonding behavior varied as a result of the differences in the coefficients of thermal expansions (CTEs) among Cu, diamond, and Cr. Moreover, the separation of interfaces had a direct influence upon the equivalent stress state of the Cu-matrix, since diamond particles only deformed elastically. It was revealed through a fully coupled thermo-mechanical FE analysis that repeated heating and cooling cycles resulted in an extremely high stress state within the Cu-matrix along the diamond interface. Since these stresses lead to interfacial debonding, their computation through numerical means may help in determining the service life of heat sinks for a given application beforehand.

  8. Flexible Automation System for Determination of Elemental Composition of Incrustations in Clogged Biliary Endoprostheses Using ICP-MS.

    Science.gov (United States)

    Fleischer, Heidi; Ramani, Kinjal; Blitti, Koffi; Roddelkopf, Thomas; Warkentin, Mareike; Behrend, Detlef; Thurow, Kerstin

    2017-08-01

    Automation systems are well established in industries and life science laboratories, especially in bioscreening and high-throughput applications. An increasing demand of automation solutions can be seen in the field of analytical measurement in chemical synthesis, quality control, and medical and pharmaceutical fields, as well as research and development. In this study, an automation solution was developed and optimized for the investigation of new biliary endoprostheses (stents), which should reduce clogging after implantation in the human body. The material inside the stents (incrustations) has to be controlled regularly and under identical conditions. The elemental composition is one criterion to be monitored in stent development. The manual procedure was transferred to an automated process including sample preparation, elemental analysis using inductively coupled plasma mass spectrometry (ICP-MS), and data evaluation. Due to safety issues, microwave-assisted acid digestion was executed outside of the automation system. The performance of the automated process was determined and validated. The measurement results and the processing times were compared for both the manual and the automated procedure. Finally, real samples of stent incrustations and pig bile were analyzed using the automation system.

  9. Numerical simulation of isothermal chemical vapor infiltration process in fabrication of carbon-carbon composites by finite element method

    Institute of Scientific and Technical Information of China (English)

    李克智; 李贺军; 姜开宇

    2000-01-01

    The chemical vapor infiltration process in fabrication of carbon-carbon composites is highly inefficient and requires long processing time. These limitations add considerably to the cost of fabrication and restrict the application of this material. Efforts have been made to study the CVI process in fabrication of carbon-carbon composites by computer simulation and predict the process parameters, density, porosity, etc. According to the characteristics of CVI process, the basic principle of FEM and mass transport, the finite element model has been established. Incremental finite element equations and the elemental stiffness matrices have been derived for the first time. The finite element program developed by the authors has been used to simulate the ICVI process in fabrication of carbon-carbon composites. Computer color display of simulated results can express the densification and distributions of density and porosity in preform clearly. The influence of process parameters on the densification of prefo

  10. Wave Propagation Analysis in Composite Laminates Containing a Delamination Using a Three-Dimensional Spectral Element Method

    Directory of Open Access Journals (Sweden)

    Fucai Li

    2012-01-01

    Full Text Available A three-dimensional spectral element method (SEM was developed for analysis of Lamb wave propagation in composite laminates containing a delamination. SEM is more efficient in simulating wave propagation in structures than conventional finite element method (FEM because of its unique diagonal form of the mass matrix. Three types of composite laminates, namely, unidirectional-ply laminates, cross-ply laminates, and angle-ply laminates are modeled using three-dimensional spectral finite elements. Wave propagation characteristics in intact composite laminates are investigated, and the effectiveness of the method is validated by comparison of the simulation results with analytical solutions based on transfer matrix method. Different Lamb wave mode interactions with delamination are evaluated, and it is demonstrated that symmetric Lamb wave mode may be insensitive to delamination at certain interfaces of laminates while the antisymmetric mode is more suited for identification of delamination in composite structures.

  11. ACTIVATION OF HUMAN BLOOD MONONUCLEARS BY LIPOPOLYSACCHARIDE OF DIFFERENT COMPOSITION

    Directory of Open Access Journals (Sweden)

    S. V. Zubova

    2010-01-01

    Full Text Available Influence of lipopolysaccharide (LPS composition upon activation of human blood mononuclears was investigated, by measuring levels of pro-inflammatory TNFα and IL-6 cytokines released by the cells. It is shown that LPS from Rhodobacter capsulatus PG, in contrast to E. coli LPS, did not activate the target cells for synthesis of the cytokines.

  12. Assessment of elemental composition, microstructure, and hardness of stainless steel endodontic files and reamers.

    Science.gov (United States)

    Darabara, Myrsini; Bourithis, Lefteris; Zinelis, Spiros; Papadimitriou, George D

    2004-07-01

    The purpose of this study was to determine the elemental composition, microstructure, and hardness of commercially available reamers, K files, and H files. Five instruments of each type from different manufacturers (Antaeos, FKG, Maillefer, Mani, and Micromega) were embedded in epoxy resin along their longitudinal axis. After metallographic grinding and polishing, the specimens were chemically etched and their microstructure investigated under an incident light microscope. The specimens were studied under a scanning electron microscope, and their elemental compositions were determined by energy dispersive X-ray microanalysis. The same surfaces were repolished and X-ray diffraction was performed. The same specimen surface was used for the assessment of the Vickers hardness (HV200) by using a microhardness tester with a 200-g load and 20-s contact time. The hardness results were statistically analyzed with two-way ANOVA and Tukey's test (a = 0.05). All files demonstrated extensively elongated grains parallel to longitudinal file axis because of cold drawing. The elemental composition of Maillefer and Mani reamers, Antaeos K files, and Mani H files were found in the range of AISI 303 SS, whereas all the rest were determined as AISI 304 SS. Two different phases (austenite SSt and martensite SSt) were identified with X-ray diffraction for all files tested. The results of hardness classified reamers in the following decreasing order (HMV200): Micromega = 673 +/- 29, Mani = 662 +/- 24, Maillefer = 601 +/- 34, Antaeos = 586 +/- 18, FKG = 557 +/- 19, and the K files (HV200): FKG = 673 +/- 16, Mani = 647 +/- 19, Maillefer = 603 +/- 41, Antaeos = 566 +/- 21, Micromega = 555 +/- 15, and the H files (HMV200): Mani = 640 +/- 12, FKG = 583 +/- 31, Maillefer = 581 +/- 5, Antaeos = 573 +/- 3, Micromega = 546 +/- 14. Although only two stainless steel alloys were used for the production of endodontic files, the differences in hardness are independent to the alloys used, implying that

  13. REVIEW: A review of in vivo experimental methods to determine the composition of the human body

    Science.gov (United States)

    Sutcliffe, J. F.

    1996-05-01

    This review of experimental methods employed in the measurement of the composition of the human body covers the developments that have occurred over the past 30 years. Early methods such as hydrodensitometry and skinfold anthropometry have been superseded by dual-energy x-ray absorptiometry and bioelectrical impedance spectroscopy. The measurement of the whole-body abundance of certain elements by isotopic dilution, neutron activation analysis and x-ray fluorescence can give important information of clinical significance, but neutron activation facilities remain available in only a few centres worldwide. The relatively simple, rapid and risk-free electrical methods such as multifrequency bioelectrical impedance analysis, which can be employed at the bedside, have been found to be more complicated in their interpretation. Electromagnetic methods may only measure the composition of the human body at its surface. X-ray computed tomography and magnetic resonance imaging have not yet been employed much in body composition measurements. Some models for the composition of the human body are reviewed.

  14. Carbon elemental and isotopic composition in mantle xenoliths from Spain: Insights on sources and petrogenetic processes

    Science.gov (United States)

    Bianchini, G.; Natali, C.

    2017-02-01

    The carbon elemental concentration (C wt%) and isotopic (δ13C ‰) composition of mantle xenoliths from the Tallante and Calatrava volcanic occurrences (in South-East and Central Spain, respectively) have been investigated to identify carbon sources and processes occurring in distinct geodynamic settings of the Iberian Peninsula. The peridotitic mantle xenoliths from Calatrava show elemental C ranging from 0.11 to 2.87 wt% which is coupled with a continuous isotopic variation from very negative values (δ13C - 26.1‰) to typical mantle values (δ13C - 5.9‰). On the other hand, the Tallante mantle xenolith suite displays lower C contents (0.06-0.15 wt%) showing a tighter variation with 13C-depleted values ranging between - 20.1 and - 23.7‰; higher elemental C up to 0.41 wt% displaying distinctly less negative isotopic values (δ13C between - 13.8 and - 11.9‰) have been recorded in veins crosscutting Tallante peridotites, plausibly representing the product of metasomatic reactions. The data from the two investigated xenolith suites invariably display a good correlation between elemental and isotopic composition, suggesting a mantle origin for carbon and Rayleigh-type fractionation as the process responsible for the observed C-δ13C variation. However, the correlation between the carbon isotopic data with other isotopic tracers (e.g. 87Sr/86Sr, 3He/4He) used to identify distinct mantle components and metasomatic reactions, indicates systematic differences between the two xenolith suites suggesting that beneath the Betic Cordillera (where Tallante is located) the deep C-cycle involves recycling, via subduction preceding/accompanying continental collision, of crustal components back in the mantle. Coherently, geochemical trends observed in the Tallante xenoliths seem to be influenced by metasomatic agents generated by melting of crustal lithologies that according to the analysis of a metasedimentary xenolith can contain C up to 1.2 wt% having δ13C of ca. - 18

  15. Patient-specific modeling of human cardiovascular system elements

    Science.gov (United States)

    Kossovich, Leonid Yu.; Kirillova, Irina V.; Golyadkina, Anastasiya A.; Polienko, Asel V.; Chelnokova, Natalia O.; Ivanov, Dmitriy V.; Murylev, Vladimir V.

    2016-03-01

    Object of study: The research is aimed at development of personalized medical treatment. Algorithm was developed for patient-specific surgical interventions of the cardiovascular system pathologies. Methods: Geometrical models of the biological objects and initial and boundary conditions were realized by medical diagnostic data of the specific patient. Mechanical and histomorphological parameters were obtained with the help mechanical experiments on universal testing machine. Computer modeling of the studied processes was conducted with the help of the finite element method. Results: Results of the numerical simulation allowed evaluating the physiological processes in the studied object in normal state, in presence of different pathologies and after different types of surgical procedures.

  16. VIBRATION ANALYSIS ON A COMPOSITE BEAM TO IDENTIFY DAMAGE AND DAMAGE SEVERITY USING FINITE ELEMENT METHOD

    Directory of Open Access Journals (Sweden)

    E.V.V.Ramanamurthy

    2011-07-01

    Full Text Available The objective of this paper is to develop a damage detection method in a composite cantilever beam with an edge crack has been studied using finite element method. A number of analytical, numerical andexperimental techniques are available for the study of damage identification in beams. Studies were carried out for three different types of analysis on a composite cantilever beam with an edge crack as damage. The material used in this analysis is glass-epoxy composite material. The finite element formulation was carried out in the analysis section of the package, known as ANSYS. The types of vibration analysis studied on a composite beam are Modal, Harmonic andTransient analysis. The crack is modeled such that the cantilever beam is replaced with two intact beams with the crack as additional boundary condition. Damage algorithms are used to identify and locate the damage. Damage index method is also used to find the severity of the damage. The results obtained from modal analysis were compared with the transient analysis results.The vibration-based damage detection methods are based on the fact that changes of physical properties (stiffness, mass and damping due to damage will manifest themselves as changes in the structural modal parameters (natural frequencies, mode shapes and modal damping. The task is then to monitor the selected indicators derived from modal parameters to distinguish between undamaged and damaged states. However, the quantitative changes of global modal parameters are not sufficiently sensitive to a local damage. The proposed approach, on the other hand, interprets the dynamic changes caused by damage in a different way. Although the basis for vibration-based damage detection appears intuitive, the implementation in real structures may encounter many significant challenges. The most fundamental issue is the fact that damage typically is a local phenomenon and may not dramatically influence the global dynamic response of a

  17. A Computational Approach for Automated Posturing of a Human Finite Element Model

    Science.gov (United States)

    2016-07-01

    following: obtaining source geometries in the posture being tested, a so- called posturing “by hand” where geometries are moved to what “looks correct ...ARL-MR-0934• JULY 2016 US Army Research Laboratory A Computational Approach for Automated Posturing of a Human Finite ElementModel by Justin McKee...Automated Posturing of a Human Finite ElementModel by Justin McKee Bennett Aerospace, Inc., Cary, NC Adam Sokolow Weapons and Materials Research

  18. Antidepressant, psychostimulant, and nootropic effects of major and trace element composition.

    Science.gov (United States)

    Afanasieva, O G; Suslov, N I; Shilova, I V

    2013-06-01

    The antidepressant, psychostimulant, and nootropic effects of a composition of major and trace elements including KCl, RbNO3, magnesium sulfate, and zinc sulfate were studied on the models of behavioural despair (Porsolt test) and conditioned passive avoidance test. The preparation was found to shorten the immobilization time in the Porsolt test and promote retention of the conditioned passive avoidance. The most pronounced psychostimulant effect of the substance was observed at a dose of 4.68 mg/kg and the most pronounced antidepressant effect was found at a dose of 18.72 mg/kg. Maximum nootropic activity of the preparation was found at a dose of 93.6 mg/kg.

  19. Trace elemental composition of curry by inductively coupled plasma optical emission spectrometry (ICP-OES).

    Science.gov (United States)

    Gonzálvez, A; Armenta, S; De La Guardia, M

    2008-01-01

    A methodology based on inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave-assisted acid digestion was developed to determine the content of traces elements in curry samples from the Spanish market. The methodology was validated in terms of accuracy by the analysis of citrus and tomato leaf reference materials achieving comparable results with the certified values. The trace metal content of curry samples was compared with data available from previously published reports concerning Indian samples, especially in terms of heavy metal composition, in order to guarantee the quality of the commercially available spices in the European countries. Values found for the analysis of arsenic, lead and cadmium were significantly lower than the maximum limit allowed by European Union statutory limits for heavy metals and lower than those obtained for Indian curry leaves reported by Indian research teams by using neutron activation and γ-ray analysis.

  20. Homotopy Iteration Algorithm for Crack Parameters Identification with Composite Element Method

    Directory of Open Access Journals (Sweden)

    Ling Huang

    2013-01-01

    Full Text Available An approach based on homotopy iteration algorithm is proposed to identify the crack parameters in beam structures. In the forward problem, a fully open crack model with the composite element method is employed for the vibration analysis. The dynamic responses of the cracked beam in time domain are obtained from the Newmark direct integration method. In the inverse analysis, an identification approach based on homotopy iteration algorithm is studied to identify the location and the depth of a cracked beam. The identification equation is derived by minimizing the error between the calculated acceleration response and the simulated measured one. Newton iterative method with the homotopy equation is employed to track the correct path and improve the convergence of the crack parameters. Two numerical examples are conducted to illustrate the correctness and efficiency of the proposed method. And the effects of the influencing parameters, such as measurement time duration, measurement points, division of the homotopy parameter and measurement noise, are studied.

  1. The maternal-effect, selfish genetic element Medea is associated with a composite Tc1 transposon.

    Science.gov (United States)

    Lorenzen, Marcé D; Gnirke, Andreas; Margolis, Jonathan; Garnes, Jeffrey; Campbell, Margie; Stuart, Jeffrey J; Aggarwal, Rajat; Richards, Stephen; Park, Yoonseong; Beeman, Richard W

    2008-07-22

    Maternal-Effect Dominant Embryonic Arrest ("Medea") factors are selfish nuclear elements that combine maternal-lethal and zygotic-rescue activities to gain a postzygotic survival advantage. We show that Medea(1) activity in Tribolium castaneum is associated with a composite Tc1 transposon inserted just downstream of the neurotransmitter reuptake symporter bloated tubules (blot), whose Drosophila ortholog has both maternal and zygotic functions. The 21.5-kb insertion contains defective copies of elongation initiation factor-3, ATP synthase subunit C, and an RNaseD-related gene, as well as a potentially intact copy of a prokaryotic DUF1703 gene. Sequence comparisons suggest that the current distribution of Medea(1) reflects global emanation after a single transpositional event in recent evolutionary time. The Medea system in Tribolium represents an unusual type of intragenomic conflict and could provide a useful vehicle for driving desirable genes into populations.

  2. The major-element composition of Mercury's surface from MESSENGER X-ray spectrometry.

    Science.gov (United States)

    Nittler, Larry R; Starr, Richard D; Weider, Shoshana Z; McCoy, Timothy J; Boynton, William V; Ebel, Denton S; Ernst, Carolyn M; Evans, Larry G; Goldsten, John O; Hamara, David K; Lawrence, David J; McNutt, Ralph L; Schlemm, Charles E; Solomon, Sean C; Sprague, Ann L

    2011-09-30

    X-ray fluorescence spectra obtained by the MESSENGER spacecraft orbiting Mercury indicate that the planet's surface differs in composition from those of other terrestrial planets. Relatively high Mg/Si and low Al/Si and Ca/Si ratios rule out a lunarlike feldspar-rich crust. The sulfur abundance is at least 10 times higher than that of the silicate portion of Earth or the Moon, and this observation, together with a low surface Fe abundance, supports the view that Mercury formed from highly reduced precursor materials, perhaps akin to enstatite chondrite meteorites or anhydrous cometary dust particles. Low Fe and Ti abundances do not support the proposal that opaque oxides of these elements contribute substantially to Mercury's low and variable surface reflectance.

  3. Yellow and red ochre pigments from southern Portugal: Elemental composition and characterization by WDXRF and XRD

    Energy Technology Data Exchange (ETDEWEB)

    Gil, M. [Conservation and Restoration Department, Science and Technology Faculty, Univ. Nova of Lisbon, Monte da Caparica, 2829-516 Caparica (Portugal); Atomic Physics Center, Lisbon University, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal)], E-mail: milenegil@gmail.com; Carvalho, M.L. [Atomic Physics Center, Lisbon University, Av. Prof. Gama Pinto 2, 1649-003 Lisbon (Portugal); Seruya, A. [Conservation and Restoration Department, Science and Technology Faculty, Univ. Nova of Lisbon, Monte da Caparica, 2829-516 Caparica (Portugal); Portuguese Institute of Conservation Restoration (IPCR), Rua das janelas Verdes 37, 1300-001 Lisbon (Portugal); Candeias, A.E. [Chemistry Department and Evora Chemistry Center, University of Evora, Rua Romao Ramalho, 59 Evora (Portugal); Mirao, J. [Giosciences Department and Evora Geophysics Center, University of Evora, Rua Romao Ramalho, 59 Evora (Portugal); Queralt, I. [Laboratory of X-ray Analytical Applications, Institute of Earth Sciences ' Jaume Almera' CSIC, Sole' Sabari' s s/n 08028 Barcelona (Spain)

    2007-09-21

    Three different yellow and red ochre pigments geological sources from Alentejo-Terras rossas, schist units and weathered iron ore deposits-were studied by elemental and phase analysis complemented with Munsell and CIELAB colour parameters. Central aims were to underline the mineralogical and chemical distinctiveness of natural pigment sources and establish a connection between local geology and use of specific colour pigments in traditional lime wash mural paintings. According to the chemical composition the Fe abundance is 6 times higher than average crust values. The Terras Rossas are characterized by higher Ca contents. In yellow and red schists, phyllosilicates are major minerals, so pigments from these units are enriched in K and Rb. Besides Fe, the pigments from weathered ores are enriched in metals like Pb, As, Cu, and Zn, which can be used as fingerprints.

  4. Apatite in carbonatitic rocks: Compositional variation, zoning, element partitioning and petrogenetic significance

    Science.gov (United States)

    Chakhmouradian, Anton R.; Reguir, Ekaterina P.; Zaitsev, Anatoly N.; Couëslan, Christopher; Xu, Cheng; Kynický, Jindřich; Mumin, A. Hamid; Yang, Panseok

    2017-03-01

    Apatite-group phosphates are nearly ubiquitous in carbonatites, but our understanding of these minerals is inadequate, particularly in the areas of element partitioning and petrogenetic interpretation of their compositional variation among spatially associated rocks and within individual crystals. In the present work, the mode of occurrence, and major- and trace-element chemistry of apatite (sensu lato) from calcite and dolomite carbonatites, their associated cumulate rocks (including phoscorites) and hydrothermal parageneses were studied using a set of 80 samples from 50 localities worldwide. The majority of this set represents material for which no analytical data are available in the literature. Electron-microprobe and laser-ablation mass-spectrometry data ( 600 and 400 analyses, respectively), accompanied by back-scattered-electron and cathodoluminescence images and Raman spectra, were used to identify the key compositional characteristics and zoning patterns of carbonatitic apatite. These data are placed in the context of phosphorus geochemistry in carbonatitic systems and carbonatite evolution, and compared to the models proposed by previous workers. The documented variations in apatite morphology and zoning represent a detailed record of a wide range of evolutionary processes, both magmatic and fluid-driven. The majority of igneous apatite from the examined rocks is Cl-poor fluorapatite or F-rich hydroxylapatite (≥ 0.3 apfu F) with 0.2-2.7 wt.% SrO, 0-4.5 wt.% LREE2O3, 0-0.8 wt.% Na2O, and low levels of other cations accommodated in the Ca site (up to 1000 ppm Mn, 2300 ppm Fe, 200 ppm Ba, 150 ppm Pb, 700 ppm Th and 150 ppm U), none of which show meaningful correlation with the host-rock type. Silicate, (SO4)2 - and (VO4)3 - anions, substituting for (PO4)3 -, tend to occur in greater abundance in crystals from calcite carbonatites (up to 4.2 wt.% SiO2, 1.5 wt.% SO3 and 660 ppm V). Although (CO3)2 - groups are very likely present in some samples, Raman micro

  5. The Model of Unreliable Elements (Human Resources) Intellectual Management System on the Basis of Their Psychological and Personal Characteristics

    OpenAIRE

    Ryabtsev, Timofey; Antonova, Elena

    2008-01-01

    The Article suggests a possible approach to creation of the Intellectual Management System for human resources and personnel (during their professional tasks solving), and that could consider personal characteristics and psychological condition of the human resources as an “unreliable” element. The Article describes some elements of the Intellectual Management System: professional activity model and “unreliable” element (human resources) model.

  6. Rhyolite magma evolution recorded in isotope and trace element composition of zircon from Halle Volcanic Complex

    Science.gov (United States)

    Słodczyk, E.; Pietranik, A.; Breitkreuz, C.; Fanning, C. M.; Anczkiewicz, R.; Ehling, B.-C.

    2016-04-01

    Voluminous felsic volcanic magmas were formed in Central Europe at the Carboniferous/Permian boundary in numerous pull-apart basins; one of which is the Saale Basin, which holds the Halle Volcanic Complex (HVC), the focus of this study. The rhyolites in the HVC formed laccoliths and scarce lavas, and occur in two different textural types: fine and coarse porphyritic. Zircon isotope and trace element composition was analysed in four units, two per each textural type. Zircon from the different units shows similar ranges in εHf (- 4.1 to - 8.1) and δ18O values (6.51-8.26), indicating similar sources and evolution processes for texturally diverse rhyolites from the HVC. Scarce inherited zircon ranges from ~ 315 Ma to ~ 2100 Ma with the major groupings around 315-550 Ma. These ages are typical for Devonian arc magmatic activity (350-400 Ma) and Cadomian igneous rocks (500-600 Ma), which occur in the basement presently underlying the HVC. Therefore, the source of the rhyolites was multicomponent and probably represented by a basement composed of various crystalline rocks. Trace elements in zircon show similar distributions in all analysed samples, which is broadly consistent with zircon cores crystallizing in a less evolved magma undergoing limited fractional crystallization, whilst the zircon rims crystallized from a magma undergoing extensive fractional crystallization of major and accessory minerals. Interestingly, comparison of the zircon composition in HVC rhyolites and other rhyolites worldwide shows that the observed trends are similar in such rhyolites despite the values being different. This may suggest that most of the zircon in rhyolites crystallizes at a similar stage in the rhyolite magma evolution, from magmas undergoing extensive crystallization of major phases and apatite. The implication is that most of the zircon represents late stage crystallization, but also that antecrystic component may be present and preserve information on the development of

  7. The analysis of adhesively bonded advanced composite joints using joint finite elements

    Science.gov (United States)

    Stapleton, Scott E.

    The design and sizing of adhesively bonded joints has always been a major bottleneck in the design of composite vehicles. Dense finite element (FE) meshes are required to capture the full behavior of a joint numerically, but these dense meshes are impractical in vehicle-scale models where a course mesh is more desirable to make quick assessments and comparisons of different joint geometries. Analytical models are often helpful in sizing, but difficulties arise in coupling these models with full-vehicle FE models. Therefore, a joint FE was created which can be used within structural FE models to make quick assessments of bonded composite joints. The shape functions of the joint FE were found by solving the governing equations for a structural model for a joint. By analytically determining the shape functions of the joint FE, the complex joint behavior can be captured with very few elements. This joint FE was modified and used to consider adhesives with functionally graded material properties to reduce the peel stress concentrations located near adherend discontinuities. Several practical concerns impede the actual use of such adhesives. These include increased manufacturing complications, alterations to the grading due to adhesive flow during manufacturing, and whether changing the loading conditions significantly impact the effectiveness of the grading. An analytical study is conducted to address these three concerns. Furthermore, proof-of-concept testing is conducted to show the potential advantages of functionally graded adhesives. In this study, grading is achieved by strategically placing glass beads within the adhesive layer at different densities along the joint. Furthermore, the capability to model non-linear adhesive constitutive behavior with large rotations was developed, and progressive failure of the adhesive was modeled by re-meshing the joint as the adhesive fails. Results predicted using the joint FE was compared with experimental results for various

  8. Hair from different ethnic groups vary in elemental composition and nitrogen and phosphorus mineralisation in soil.

    Science.gov (United States)

    Malepfane, N M; Muchaonyerwa, P

    2017-02-01

    Disposal of hair wastes at landfills causes nitrate leaching to ground water, and use of the waste as fertiliser could be a viable option. This study was to determine elemental composition of major hair types in South Africa and their nitrogen (N) and phosphorus (P) release in soil. Wastes of African, White and Indian hair were obtained from local salons and analysed for carbon (C), N and sulphur (S) with the Leco CNS analyzer, and P, bases, aluminium (Al) and micronutrients, with the ICP. We also conducted an incubation study to determine changes in mineral N and P in soil. Hair wastes were added to soil at increasing rates based on N, incubated at 25 °C with destructive sampling after 0, 28, 56 and 84 days and pH, ammonium-N, nitrate-N and extractable P measured. All data were subjected to analysis of variance. Indian and White hair had higher N than African. White hair had higher C and lower potassium (K) than those of other types. The Fe levels in hair were in the order White > African > Indian, whilst those of Al were African > Indian > White. African hair had higher calcium (Ca), manganese (Mn), zinc (Zn) and cobalt (Co) than the other types. Ammonium-N and nitrate-N releases were in the order: Indian > African > White, especially at higher rates. Ammonium-N increased in the first 28 days and declined thereafter, when nitrate-N increased and pH decreased. The findings implied that hair types differ in elemental composition and nitrogen release in soil, with implications on pollution and soil fertility.

  9. The Analysis of Adhesively Bonded Advanced Composite Joints Using Joint Finite Elements

    Science.gov (United States)

    Stapleton, Scott E.; Waas, Anthony M.

    2012-01-01

    The design and sizing of adhesively bonded joints has always been a major bottleneck in the design of composite vehicles. Dense finite element (FE) meshes are required to capture the full behavior of a joint numerically, but these dense meshes are impractical in vehicle-scale models where a course mesh is more desirable to make quick assessments and comparisons of different joint geometries. Analytical models are often helpful in sizing, but difficulties arise in coupling these models with full-vehicle FE models. Therefore, a joint FE was created which can be used within structural FE models to make quick assessments of bonded composite joints. The shape functions of the joint FE were found by solving the governing equations for a structural model for a joint. By analytically determining the shape functions of the joint FE, the complex joint behavior can be captured with very few elements. This joint FE was modified and used to consider adhesives with functionally graded material properties to reduce the peel stress concentrations located near adherend discontinuities. Several practical concerns impede the actual use of such adhesives. These include increased manufacturing complications, alterations to the grading due to adhesive flow during manufacturing, and whether changing the loading conditions significantly impact the effectiveness of the grading. An analytical study is conducted to address these three concerns. Furthermore, proof-of-concept testing is conducted to show the potential advantages of functionally graded adhesives. In this study, grading is achieved by strategically placing glass beads within the adhesive layer at different densities along the joint. Furthermore, the capability to model non-linear adhesive constitutive behavior with large rotations was developed, and progressive failure of the adhesive was modeled by re-meshing the joint as the adhesive fails. Results predicted using the joint FE was compared with experimental results for various

  10. Modification of a Macromechanical Finite-Element Based Model for Impact Analysis of Triaxially-Braided Composites

    Science.gov (United States)

    Goldberg, Robert K.; Blinzler, Brina J.; Binienda, Wieslaw K.

    2010-01-01

    A macro level finite element-based model has been developed to simulate the mechanical and impact response of triaxially-braided polymer matrix composites. In the analytical model, the triaxial braid architecture is simulated by using four parallel shell elements, each of which is modeled as a laminated composite. For the current analytical approach, each shell element is considered to be a smeared homogeneous material. The commercial transient dynamic finite element code LS-DYNA is used to conduct the simulations, and a continuum damage mechanics model internal to LS-DYNA is used as the material constitutive model. The constitutive model requires stiffness and strength properties of an equivalent unidirectional composite. Simplified micromechanics methods are used to determine the equivalent stiffness properties, and results from coupon level tests on the braided composite are utilized to back out the required strength properties. Simulations of quasi-static coupon tests of several representative braided composites are conducted to demonstrate the correlation of the model. Impact simulations of a represented braided composites are conducted to demonstrate the capability of the model to predict the penetration velocity and damage patterns obtained experimentally.

  11. Trace elements in human physiology and pathology. Copper.

    Science.gov (United States)

    Tapiero, H; Townsend, D M; Tew, K D

    2003-11-01

    Copper is a trace element, important for the function of many cellular enzymes. Copper ions can adopt distinct redox states oxidized Cu(II) or reduced (I), allowing the metal to play a pivotal role in cell physiology as a catalytic cofactor in the redox chemistry of enzymes, mitochondrial respiration, iron absorption, free radical scavenging and elastin cross-linking. If present in excess, free copper ions can cause damage to cellular components and a delicate balance between the uptake and efflux of copper ions determines the amount of cellular copper. In biological systems, copper homeostasis has been characterized at the molecular level. It is coordinated by several proteins such as glutathione, metallothionein, Cu-transporting P-type ATPases, Menkes and Wilson proteins and by cytoplasmic transport proteins called copper chaperones to ensure that it is delivered to specific subcellular compartments and thereby to copper-requiring proteins.

  12. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy

    Science.gov (United States)

    González-Martín, M. Inmaculada; Escuredo, Olga; Revilla, Isabel; Vivar-Quintana, Ana M.; Coello, M. Carmen; Palacios Riocerezo, Carlos; Wells Moncada, Guillermo

    2015-01-01

    The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption. PMID:26540058

  13. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    M. Inmaculada González-Martín

    2015-11-01

    Full Text Available The potential of near infrared spectroscopy (NIR with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region and Spain (Castilla-León and Galicia regions. The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS regression method was used to develop the NIR calibration model. The determination coefficient (R2 and root mean square error of prediction (RMSEP obtained for aluminum (0.79, 53, calcium (0.83, 94, iron (0.69, 134 potassium (0.95, 117, magnesium (0.70, 99, phosphorus (0.94, 24 zinc (0.87, 10 chromium (0.48, 0.6 nickel (0.52, 0.7 copper (0.64, 0.9 and lead (0.70, 2 in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption.

  14. Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions

    Science.gov (United States)

    Praplan, A. P.; Schobesberger, S.; Bianchi, F.; Rissanen, M. P.; Ehn, M.; Jokinen, T.; Junninen, H.; Adamov, A.; Amorim, A.; Dommen, J.; Duplissy, J.; Hakala, J.; Hansel, A.; Heinritzi, M.; Kangasluoma, J.; Kirkby, J.; Krapf, M.; Kürten, A.; Lehtipalo, K.; Riccobono, F.; Rondo, L.; Sarnela, N.; Simon, M.; Tomé, A.; Tröstl, J.; Winkler, P. M.; Williamson, C.; Ye, P.; Curtius, J.; Baltensperger, U.; Donahue, N. M.; Kulmala, M.; Worsnop, D. R.

    2015-04-01

    This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1) pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH) scavenger) and (2) OH oxidation (initiated by nitrous acid (HONO) photolysis by ultraviolet light) in the absence of ozone. We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF) mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate). Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition of oxidation products and their clustering behaviour, several instruments must be used. We compare oxidation products containing 10 and 20 carbon atoms and show that highly oxidised organic compounds are formed in the early stages of the oxidation.

  15. Elemental composition and clustering behaviour of α-pinene oxidation products for different oxidation conditions

    Directory of Open Access Journals (Sweden)

    A. P. Praplan

    2015-04-01

    Full Text Available This study presents the difference between oxidised organic compounds formed by α-pinene oxidation under various conditions in the CLOUD environmental chamber: (1 pure ozonolysis (in the presence of hydrogen as hydroxyl radical (OH scavenger and (2 OH oxidation (initiated by nitrous acid (HONO photolysis by ultraviolet light in the absence of ozone. We discuss results from three Atmospheric Pressure interface Time-of-Flight (APi-TOF mass spectrometers measuring simultaneously the composition of naturally charged as well as neutral species (via chemical ionisation with nitrate. Natural chemical ionisation takes place in the CLOUD chamber and organic oxidised compounds form clusters with nitrate, bisulfate, bisulfate/sulfuric acid clusters, ammonium, and dimethylaminium, or get protonated. The results from this study show that this process is selective for various oxidised organic compounds with low molar mass and ions, so that in order to obtain a comprehensive picture of the elemental composition of oxidation products and their clustering behaviour, several instruments must be used. We compare oxidation products containing 10 and 20 carbon atoms and show that highly oxidised organic compounds are formed in the early stages of the oxidation.

  16. Compositional modeling of three-phase flow with gravity using higher-order finite element methods

    Science.gov (United States)

    Moortgat, Joachim; Sun, Shuyu; Firoozabadi, Abbas

    2011-05-01

    A wide range of applications in subsurface flow involve water, a nonaqueous phase liquid (NAPL) or oil, and a gas phase, such as air or CO2. The numerical simulation of such processes is computationally challenging and requires accurate compositional modeling of three-phase flow in porous media. In this work, we simulate for the first time three-phase compositional flow using higher-order finite element methods. Gravity poses complications in modeling multiphase processes because it drives countercurrent flow among phases. To resolve this issue, we propose a new method for the upwinding of three-phase mobilities. Numerical examples, related to enhanced oil recovery and carbon sequestration, are presented to illustrate the capabilities of the proposed algorithm. We pay special attention to challenges associated with gravitational instabilities and take into account compressibility and various phase behavior effects, including swelling, viscosity changes, and vaporization. We find that the proposed higher-order method can capture sharp solution discontinuities, yielding accurate predictions of phase boundaries arising in computational three-phase flow. This work sets the stage for a broad extension of the higher-order methods for numerical simulation of three-phase flow for complex geometries and processes.

  17. Changes in element composition along the spinning duct in a Nephila spider

    Science.gov (United States)

    Knight, David; Vollrath, Fritz

    2001-05-01

    The silk gland of the golden orb spider Nephila edulis connects to the exit spigot through a long S-shaped duct that assists in the formation of the thread. Previous evidence suggests that the epithelium of the distal (last) part of the duct is specialized for ion transport and that a proton pump is involved in this process. Here, we present evidence from SEM (scanning electron microscope)-EDAX (energy dispersive X-ray) microanalysis of rapidly frozen material maintained at approximately -150°C and from the use of pH indicators that the element composition and pH change progressively as the dragline silk dope (spinning solution) passes down the duct to form the thread. Na+ and Cl- composition decreased while K+ and P and S increased. Indicators suggested that the pH dropped from 6.9+/-0.1 to 6.3+/-0.1. These novel findings suggest that the absorption of Na+ and secretion of the more chaotropic K+ may help the silk protein molecules to refold while the secretion of H+ may assist in this process and reduce the repulsive charges on them. This in turn may allow the molecules to approach one another more closely to crystallize. Thus precise control of the ionic environment within the spider's spinning duct may be important in forming a tough insoluble thread and when devising mimetic processes to spin silk proteins industrially.

  18. Comparison of Tensile Strength of Composite Material Elements with Drilled and Molded-in Holes

    Science.gov (United States)

    Langella, A.; Durante, M.

    2008-11-01

    Holes are generally obtained through drilling operations; this causes a property decrease for polymer composites reinforced by fibers, brought about by damage due to fiber continuity interruption, and to delamination between the laminate layers. In this study, specimens with circular holes, both drilled and molded-in, obtained in different ways, are tested in order to investigate on whether it is possible to avoid the decrease in mechanical properties of components with holes. In particular, a number of laminates were manufactured by RIFT (Resin Infusion under Flexible Tool), a closed mold process capable of obtaining large and complex forms, impregnating, under vacuum, a dry preform placed on the rigid mold. At specific points of these laminates, molded-in holes are generated during the resin infusion phase, operating in two different ways: displacing or cutting the fibers in the dry preform. Tensile tests were carried out in order to compare the mechanical properties of elements in composite materials which have molded-in holes generated during the impregnation process, with the properties of those with holes produced after the resin cure by drill operations.

  19. Compositional modeling of three-phase flow with gravity using higher-order finite element methods

    KAUST Repository

    Moortgat, Joachim

    2011-05-11

    A wide range of applications in subsurface flow involve water, a nonaqueous phase liquid (NAPL) or oil, and a gas phase, such as air or CO2. The numerical simulation of such processes is computationally challenging and requires accurate compositional modeling of three-phase flow in porous media. In this work, we simulate for the first time three-phase compositional flow using higher-order finite element methods. Gravity poses complications in modeling multiphase processes because it drives countercurrent flow among phases. To resolve this issue, we propose a new method for the upwinding of three-phase mobilities. Numerical examples, related to enhanced oil recovery and carbon sequestration, are presented to illustrate the capabilities of the proposed algorithm. We pay special attention to challenges associated with gravitational instabilities and take into account compressibility and various phase behavior effects, including swelling, viscosity changes, and vaporization. We find that the proposed higher-order method can capture sharp solution discontinuities, yielding accurate predictions of phase boundaries arising in computational three-phase flow. This work sets the stage for a broad extension of the higher-order methods for numerical simulation of three-phase flow for complex geometries and processes.

  20. Another Approach to Measuring Human Development: The Composite Dynamic Human Development Index

    Science.gov (United States)

    Bilbao-Ubillos, Javier

    2013-01-01

    This paper seeks mainly to contribute to the debate on how the relative degree of development of a country should be measured by proposing an indicator to build on the valuable starting point provided by the Human Development Index (HDI). The indicator proposed is called the "Composite, Dynamic Human Development Index". It incorporates in a simple…

  1. Another Approach to Measuring Human Development: The Composite Dynamic Human Development Index

    Science.gov (United States)

    Bilbao-Ubillos, Javier

    2013-01-01

    This paper seeks mainly to contribute to the debate on how the relative degree of development of a country should be measured by proposing an indicator to build on the valuable starting point provided by the Human Development Index (HDI). The indicator proposed is called the "Composite, Dynamic Human Development Index". It incorporates in a simple…

  2. Contraction behaviors of dental composite restorations--finite element investigation with DIC validation.

    Science.gov (United States)

    Chuang, Shu-Fen; Chang, Chih-Han; Chen, Terry Yuan-Fang

    2011-11-01

    The objective of this study was to examine the effects of cavity configuration on the polymerization shrinkage and stress of light-cured composite restorations by combining local strain measurement and a finite element analysis (FEA). Dental mesio-occluso-distal cavities of various widths and depths (each for 2 vs. 4 mm), representing different configuration factors, were prepared on extracted molars. The displacements of the bonded tooth cusps and cavity floors, caused by polymerization shrinkage of composite restorations, were assessed utilizing a digital-image-correlation (DIC) technique. The cervical marginal microleakage was investigated by examining the resin replicas of these restorations under SEM. The local material properties of the polymerized composite along the curing depth were defined by the nanoindentation test and applied in the subsequent FEA. In the FEA, four models were generated to correspond with the experimental restorations. In the DIC measurement results, the 4(w)×4(D) mm cavity presented the greatest values of inward displacements at the cusp and floor. The cavity depth, rather than the cavity width, was found to significantly correlate to the floor deformation, the location of shrinkage centers, and also the cervical microleakage ratio. The FEA simulation results showed that the 2(w)×4(D) mm cavity presented the maximal von Mises and principal stress located respectively on the cervical margins and cavity floor. Additional safety factor analysis showed a high risk of bond failure over the cavity floor in the 4-mm deep cavity. With the experimental validation, the simulation revealed that the cavity depth was significant to the formation of contraction stress and the incidence of interfacial debonding.

  3. Free Edge Mixed Mode Delamination Analysis of Laminated Composites with Wrap-Around Configuration: A Finite Element Study

    Science.gov (United States)

    Choudhury, Pannalal; Das, Subhankar; Halder, Sudipta; Pandey, Krishna Murari

    2016-10-01

    Finite element analyses of laminated composites were done in the present study with respect to suppression of free edge delamination by an innovative technique. Wrap-around configuration was considered to determine its effectiveness over the wrapper-less laminated configuration on laminated composites. Nodal stresses were generated ahead of the crack tip through finite element analysis. This was used for determining interlaminar normal stress and inter laminar shear stress distributions at the critical interface. Later virtual crack closure technique was used to estimate the strain energy release rate components for several sizes of virtual crack extensions through a single finite element analysis. Computational analysis predicts Mode-I delamination as dominant mode of failure. This mode of delamination was significantly suppressed with wrap-around configuration on laminated composites.

  4. A brief review on the Human Encyclopedia of DNA Elements (ENCODE) project.

    Science.gov (United States)

    Qu, Hongzhu; Fang, Xiangdong

    2013-06-01

    The ENCyclopedia Of DNA Elements (ENCODE) project is an international research consortium that aims to identify all functional elements in the human genome sequence. The second phase of the project comprised 1640 datasets from 147 different cell types, yielding a set of 30 publications across several journals. These data revealed that 80.4% of the human genome displays some functionality in at least one cell type. Many of these regulatory elements are physically associated with one another and further form a network or three-dimensional conformation to affect gene expression. These elements are also related to sequence variants associated with diseases or traits. All these findings provide us new insights into the organization and regulation of genes and genome, and serve as an expansive resource for understanding human health and disease.

  5. Characteristic Elemental Composition of Oil Pigments using Instrumental Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Sam; Kim, Sun Ha; Sun, Gwang Min; Lim, Jong Myung; Moon, Jong Hwa; Kim, Young Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lim, Sung Jin; Song, Yu Na; Kim, Ken [National Museum of Contemporary Art, Gwacheon (Korea, Republic of)

    2009-10-15

    The principal aim of this study is to identify the applicability of instrumental neutron activation analysis as a non-destructive examination tool for the quantitative composition analysis associated with authentication, restoration, and conservation of art objects in the field of cultural heritage. Generally, the chemical composition of pigments are associated with the colors such as white, yellow, orange, red, green, blue and black, and it varies with raw materials of pigments. According to the colors of a different pigments, chemical compositions are as follows; for example, white pigments were used for a mixture of Pb(CO{sub 3}){sub 2}, PbSO{sub 4}, PbO, Pb(OH){sub 2}, ZnO, ZnS, TiO{sub 2}, BaSO{sub 4}, CaCO{sub 3}, Al{sub 2}O{sub 3}, As{sub 2}S{sub 3}, etc.; black pigments were series of carbon black, borne ash, MnO+Mn{sub 2}O{sub 3}, etc.; red pigments were Fe{sub 2}O{sub 3}, Pb{sub 3}O{sub 4}, HgS, PbMo{sub 4}, CdS+CdSe, etc.; brown and yellow pigments were PbCrO{sub 4}, ZnCrO{sub 4}, CdS-ZnS, K{sub 3}[Co(NO{sub 2}){sub 6}], Pb(SbO{sub 3}){sub 2}, C{sub 19}H{sub 16}O{sub 11}Mg, SrCrO{sub 4}, etc.; green pigments were Cr{sub 2}O{sub 3}, Cr{sub 2}O(OH){sub 4}, Cu(C{sub 2}H{sub 3}O{sub 2})-2Cu(OH){sub 2}), Cr{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-CoO, etc.; blue pigments were Fe{sub 4}[Fe(CN){sub 6}]{sub 3}, CoO-Al{sub 2}O{sub 3}, Na{sub 8}-{sub 10}Al{sub 6}Si{sub 6}O{sub 24}S{sub 2-4}, etc. This first step is to obtain quantitative data on the concentrations of major, minor and trace elements in oil pigments and to explain pigment sources by statistical treatment as reported in many literatures. The determination of major, minor and micro elements in the subject materials are essential in many fields of basic science and technology as well as commercial and industrial fields. In particular, direct analysis of a sample offers a more effective investigation method in these fields. Instrumental neutron activation analysis (INAA) has an inherent advantage of being a

  6. Composite renal cell carcinoma with clear cell renal cell carcinomatous and carcinoid tumoral elements: a first case report.

    Science.gov (United States)

    Bressenot, A; Delaunay, C; Gauchotte, G; Oliver, A; Boudrant, G; Montagne, K

    2010-02-01

    Renal endocrine tumours are extremely rare, and carcinoid tumoral elements in renal cell carcinoma have never been reported. This is the first report of a composite renal cell carcinoma containing a clear cell renal cell carcinoma associated with carcinoid tumoral elements, in a patient with synchronous metastatic disease. In the absence of specific radiological and clinical manifestations, typical morphological features as well as an immunostaining profile of neuroendocrine differentiation were identified by microscopy. Secondary nodal and liver localisations were characterised by carcinoid elements only. Despite antiangiogenic therapy, liver metastasis progressed, suggesting that adjuvant therapy cannot be based on the presence of the clear cell renal cell carcinoma component. In this context, extensive tissue sampling is recommended to reveal the endocrine component that is the most aggressive element of such a composite carcinoma.

  7. Identification of the Human Zinc Transcriptional Regulatory Element (ZTRE)

    Science.gov (United States)

    Coneyworth, Lisa J.; Jackson, Kelly A.; Tyson, John; Bosomworth, Helen J.; van der Hagen, Eline; Hann, Georgia M.; Ogo, Ogo A.; Swann, Daniel C.; Mathers, John C.; Valentine, Ruth A.; Ford, Dianne

    2012-01-01

    Many genes with crucial roles in zinc homeostasis in mammals respond to fluctuating zinc supply through unknown mechanisms, and uncovering these mechanisms is essential to understanding the process at cellular and systemic levels. We detected zinc-dependent binding of a zinc-induced protein to a specific sequence, the zinc transcriptional regulatory element (ZTRE), in the SLC30A5 (zinc transporter ZnT5) promoter and showed that substitution of the ZTRE abrogated the repression of a reporter gene in response to zinc. We identified the ZTRE in other genes, including (through an unbiased search) the CBWD genes and (through targeted analysis) in multiple members of the SLC30 family, including SLC30A10, which is repressed by zinc. The function of the CBWD genes is currently unknown, but roles for homologs in metal homeostasis are being uncovered in bacteria. We demonstrated that CBWD genes are repressed by zinc and that substitution of the ZTRE in SLC30A10 and CBWD promoter-reporter constructs abrogates this response. Other metals did not affect expression of the transcriptional regulator, binding to the ZTRE or promoter-driven reporter gene expression. These findings provide the basis for elucidating how regulation of a network of genes through this novel mechanism contributes to zinc homeostasis and how the cell orchestrates this response. PMID:22902622

  8. Repeat-element driven activation of proto-oncogenes in human malignancies.

    Science.gov (United States)

    Lamprecht, Björn; Bonifer, Constanze; Mathas, Stephan

    2010-11-01

    Recent data demonstrated that the aberrant activity of endogenous repetitive elements of the DNA in humans can drive the expression of proto-oncogenes. This article summarizes these results and gives an outlook on the impact of these findings on the pathogenesis and therapy of human cancer.

  9. Effects of soil lanthanum on growth and elemental composition of plants

    Science.gov (United States)

    Fastovets, Ilya; Kotelnikova, Anna; Olga, Rogova; Nikolai, Sushkov; Elena, Pashkevich

    2017-04-01

    Effects of soil lanthanum on growth and elemental composition of plants In recent years, lanthanum (La) has been found effective in increasing crop productivity. This results in its growing application in agriculture. However, it is controversial whether lanthanum has beneficial or negative impact on plants (Kabata-Pendias, 2011). In the present study we carried out a pot experiment to understand how soil La affects barley (Hordeum vulgare L., 'Mikhaylovsky' cv.) growth and elemental composition. The pot experiment was conducted in a growbox under artificial light in sod-podzolic soil. The soil was sprayed with LaCl3 solutions to achieve the following concentrations of exogenous La: 0 (control), 10, 20, 50, 100, and 200 mg/kg. The plants were grown for 40 days in 2-litre pots, 6 plants in each pot, with 4 replications per group (24 pots total), and were irrigated with distilled water. Fresh aboveground biomass was weighed, chlorophylls α and β and carotenoids were measured in fresh leaves. Dry leaves, stems and soil were subject to atomic emission (ICP-AES) elemental analysis. Statistical computations involved simulated Kruskal-Wallis and Jonckheere-Terpstra tests as well as Gao modification of Campbell-Skillings test for nonparametric multiple comparisons. Multiple regression and correlation analyzes were also performed. All differences were considered significant at α=0.05. Our results indicate that both leaves and stems of barley readily accumulate La. Leaves accumulate up to 1.2% of soil La concentration, and significantly more La than stems. Significant accumulation of La by stems and leaves was observed in pots with La soil concentrations higher than 50 and 20 mg/kg, respectively. Plant biomass uniformly increases up to 13.5 % compared to the control, and significant increase in plant biomass was observed at concentrations 100 and 200 mg/kg La. Chlorophyll α and β and carotenoid content decrease significantly at 100 mg/kg La compared to the control group

  10. Human pulp response to a new composite system. Vytol composite restorative and bonding agent.

    Science.gov (United States)

    Dalleske, R L; Stanley, H R; Heyde, J B

    1978-09-01

    A new two-paste composite system (Vytol and Vytol Bonding Agent) was evaluated to establish its level of pulpal response in human teeth and to determine whether a calcium hydroxide base is required. Class V cavity preparations were cut in seventy-two teeth of ten male patients whose ages averaged 52.5 years. The teeth were restored and extracted at 1 to 7 days, 12 to 14 days, and 47 to 56 days. Histologic evaluation indicated that the unlined Vytol System reacted very similarly to other commercially available composite restorative materials and that a calcium hydroxide base is effective in reducing or eliminating adverse pulp responses.

  11. Direct Determination of 3D Distribution of Elemental Composition in Single Semiconductor Nanoislands by Scanning Auger Microscopy

    Science.gov (United States)

    Ponomaryov, Semyon S.; Yukhymchuk, Volodymyr O.; Lytvyn, Peter M.; Valakh, Mykhailo Ya

    2016-02-01

    An application of scanning Auger microscopy with ion etching technique and effective compensation of thermal drift of the surface analyzed area is proposed for direct local study of composition distribution in the bulk of single nanoislands. For GexSi1 - x-nanoislands obtained by MBE of Ge on Si-substrate gigantic interdiffusion mixing takes place both in the open and capped nanostructures. Lateral distributions of the elemental composition as well as concentration-depth profiles were recorded. 3D distribution of the elemental composition in the d-cluster bulk was obtained using the interpolation approach by lateral composition distributions in its several cross sections and concentration-depth profile. It was shown that there is a germanium core in the nanoislands of both nanostructure types, which even penetrates the substrate. In studied nanostructures maximal Ge content in the nanoislands may reach about 40 at.%.

  12. Enrichment Factor and profiles of elemental composition of PM 2.5 in the city of Guadalajara, Mexico.

    Science.gov (United States)

    Hernández-Mena, Leonel; Murillo-Tovar, Mario; Ramírez-Muñíz, Martín; Colunga-Urbina, Edith; de la Garza-Rodríguez, Iliana; Saldarriaga-Noreña, Hugo

    2011-11-01

    In this study, the Enrichment Factors and elemental composition profiles of the PM2.5 were used to suggest the emission sources. The selected sites were Miravalle and Centro, and in both cases there were high values lead, Cadmium, Cobalt, Chromium, Cupper, Molybdenum, Nickel, Antimony, Selenium and Zinc for EF (>5), suggesting an anthropogenic origin. The remaining elements (Iron, Magnesium, Manganese, Strontium and Titanium) had Enrichment Factors <5, attributable to a geological origin, probably due to the suspension of particles from motor vehicles or wind. Comparing the elemental composition profiles of the two sites allowed establishing similarities with some reference profiles (SPECIATE database Version 4.2-EPA) from sources such as Paved Road Dust (PRD) and Industrial Soil (IS) and profiles of combustion sources such as Diesel Exhaust (DE). Through the estimation the Enrichment Factors and of the elemental composition profiles of two different sites in the city, it was possible to suggest not only the general type of emission source (geological or anthropogenic), but also more specific sources based on elemental composition of PM2.5.

  13. Effect of Fiber Geometry and Representative Volume Element on Elastic and Thermal Properties of Unidirectional Fiber-Reinforced Composites

    Directory of Open Access Journals (Sweden)

    Siva Bhaskara Rao Devireddy

    2014-01-01

    Full Text Available The aim of present work is focused on the evaluation of elastic and thermal properties of unidirectional fiber-reinforced polymer composites with different volume fractions of fiber up to 0.7 using micromechanical approach. Two ways for calculating the material properties, that is, analytical and numerical approaches, were presented. In numerical approach, finite element analysis was used to evaluate the elastic modulus and thermal conductivity of composite from the constituent material properties. The finite element model based on three-dimensional micromechanical representative volume element (RVE with a square and hexagonal packing geometry was implemented by using finite element code ANSYS. Circular cross section of fiber and square cross section of fiber were considered to develop RVE. The periodic boundary conditions are applied to the RVE to calculate elastic modulus of composite. The steady state heat transfer simulations were performed in thermal analysis to calculate thermal conductivity of composite. In analytical approach, the elastic modulus is calculated by rule of mixture, Halpin-Tsai model, and periodic microstructure. Thermal conductivity is calculated analytically by using rule of mixture, the Chawla model, and the Hashin model. The material properties obtained using finite element techniques were compared with different analytical methods and good agreement was achieved. The results are affected by a number of parameters such as volume fraction of the fibers, geometry of fiber, and RVE.

  14. Obsidians from the Kerkennah Islands (eastern Tunisia) and the PIXE elemental compositions of the Mediterranean peralkaline obsidians

    Energy Technology Data Exchange (ETDEWEB)

    Le Bourdonnec, François-Xavier, E-mail: Francois-Xavier.Le-Bourdonnec@u-bordeaux-montaigne.fr [Institut de Recherche sur les Archéomatériaux (IRAMAT), Centre de Recherche en Physique Appliquée à l’Archéologie (CRP2A), UMR 5060, CNRS-Université Bordeaux Montaigne, Maison de l’Archéologie, Esplanade des Antilles, 33607 Pessac Cédex (France); Poupeau, Gérard [Institut de Recherche sur les Archéomatériaux (IRAMAT), Centre de Recherche en Physique Appliquée à l’Archéologie (CRP2A), UMR 5060, CNRS-Université Bordeaux Montaigne, Maison de l’Archéologie, Esplanade des Antilles, 33607 Pessac Cédex (France); UMR 7194 CNRS et Département de Préhistoire du Muséum National d’Histoire Naturelle, Place du Trocadéro, 75016 Paris (France); Boussofara, Ridha, E-mail: ridha57@yahoo.fr [The National Heritage Institute, 4 Place du Château, 1008 Tunis (Tunisia); and others

    2015-09-01

    The provenance of 37 obsidians from the Kerkennah Islands (central Mediterranean Sea) was determined by PIXE. It is shown that they came from the two main obsidian sources, Balata dei Turchi and Lago di Venere, of the Pantelleria Island. A comparison of the PIXE elemental composition of geological vs. archaeological obsidians of central and western Mediterranean shows that their sources present elemental compositions homogeneous enough to make possible sourcing studies. However, a comparison between the distributions of geological and archaeological obsidians chemistry shows that the PIXE source qualifications do not cover yet the whole of their internal variations.

  15. Obsidians from the Kerkennah Islands (eastern Tunisia) and the PIXE elemental compositions of the Mediterranean peralkaline obsidians

    Science.gov (United States)

    Le Bourdonnec, François-Xavier; Poupeau, Gérard; Boussofara, Ridha; Dubernet, Stéphan; Moretto, Philippe; Compin, Matthieu; Mulazzani, Simone

    2015-09-01

    The provenance of 37 obsidians from the Kerkennah Islands (central Mediterranean Sea) was determined by PIXE. It is shown that they came from the two main obsidian sources, Balata dei Turchi and Lago di Venere, of the Pantelleria Island. A comparison of the PIXE elemental composition of geological vs. archaeological obsidians of central and western Mediterranean shows that their sources present elemental compositions homogeneous enough to make possible sourcing studies. However, a comparison between the distributions of geological and archaeological obsidians chemistry shows that the PIXE source qualifications do not cover yet the whole of their internal variations.

  16. 75 FR 18548 - In the Matter of Certain Products and Pharmaceutical Compositions Containing Recombinant Human...

    Science.gov (United States)

    2010-04-12

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION In the Matter of Certain Products and Pharmaceutical Compositions Containing Recombinant Human... pharmaceutical compositions containing recombinant human erythropoietin by reason of infringement of claims 1...

  17. [Comparison of 51 element contents in normal human lung tissue over twenty years].

    Science.gov (United States)

    Zeng, Jing; Ouyang, Li; Wang, Xiao-Yan; Liu, Ya-Qiong; Xie, Qing; Chu, Hong-Da; Wu, Quan; Fan, Ti-Qiang; Wang, Jing-Yu

    2008-05-01

    Changes in content and distribution of elements in human tissues may reflect changes in environmental backgrounds, and are closely related to human health. To investigate the change in element background in normal lung tissue in different stage, we used ICP-MS, ICP-AES and GFAAS to determine 51 element contents in normal human lung samples of 1982-83 year (n = 7) and compare with those of 2004-05 year (n = 16). Samples were from healthy male adults who died suddenly, and were treated with microwave digestion and wet digestion method. The results show that the contents of 23 elements (Na, Mg, P, K, As, Mo, Ag, Ba, Bi, Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) are significantly higher, and 6 elements (Zn, Ga, Ge, Se, Au and Zr) are significantly lower in the 2004-05 samples than those in the 1982-83 samples. This difference would be related to the changes in environmental backgrounds and people's living habit during twenty years. The distinctive decrease in contents of the 2004-05 samples for most measured rare earth elements (REEs) may be due to more rational usage of REEs in present, while were the soil and corps were largely abused in 1980s in China. The significant increase in contents of some useful micro-elements (Zn and Se ) in the present samples maybe because of the increased intake of these elements as people own more health consciousness. Besides, the increased contents of heavy metal Pb, Cd, Cr and Ni in the present samples may be related to the deterioration of air quality as industrialization course. More than half of measured elements have been significantly changed over twenty years, indicating that some normal value ranges of element contents should be adjusted according to the difference.

  18. Compositional change in hu-man enamel irradiated with MIR free electron laser

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The purpose of this study was to investigate compositional changes in human enamel irradiated with the free electron laser (FEL). The exposure on dental enamel at the wavelength of 9.64 ?m was observed with the Beijing free electron laser. The distribution of elements in the irradiated or non-irradiated enamel was measured by scanning electron microscope (SEM) with energy-dispersive spectroscopy and synchrotron radiation X-ray fluorescence (SRXRF) in Beijing Synchrotron Radiation Facility (BSRF). The results showed that the P/Ca ratio in the ablation region of enamel at the maximum wavelength of infrared absorption was obviously smaller than that at the non-maximum wavelength. In the ablation region the ratios of P/Ca and Ca/Sr were smaller than those in the non-ablation region. The distributions of P, Ca and Sr in the ablation region were heterogeneous due to the element change caused by FEL irradiation.

  19. Characterization and distribution of repetitive elements in association with genes in the human genome.

    Science.gov (United States)

    Liang, Kai-Chiang; Tseng, Joseph T; Tsai, Shaw-Jenq; Sun, H Sunny

    2015-08-01

    Repetitive elements constitute more than 50% of the human genome. Recent studies implied that the complexity of living organisms is not just a direct outcome of a number of coding sequences; the repetitive elements, which do not encode proteins, may also play a significant role. Though scattered studies showed that repetitive elements in the regulatory regions of a gene control gene expression, no systematic survey has been done to report the characterization and distribution of various types of these repetitive elements in the human genome. Sequences from 5' and 3' untranslated regions and upstream and downstream of a gene were downloaded from the Ensembl database. The repetitive elements in the neighboring of each gene were identified and classified using cross-matching implemented in the RepeatMasker. The annotation and distribution of distinct classes of repetitive elements associated with individual gene were collected to characterize genes in association with different types of repetitive elements using systems biology program. We identified a total of 1,068,400 repetitive elements which belong to 37-class families and 1235 subclasses that are associated with 33,761 genes and 57,365 transcripts. In addition, we found that the tandem repeats preferentially locate proximal to the transcription start site (TSS) of genes and the major function of these genes are involved in developmental processes. On the other hand, interspersed repetitive elements showed a tendency to be accumulated at distal region from the TSS and the function of interspersed repeat-containing genes took part in the catabolic/metabolic processes. Results from the distribution analysis were collected and used to construct a gene-based repetitive element database (GBRED; http://www.binfo.ncku.edu.tw/GBRED/index.html). A user-friendly web interface was designed to provide the information of repetitive elements associated with any particular gene(s). This is the first study focusing on the gene

  20. Elemental X-ray mapping of agglutinated foraminifer tests: a non- destructive technique for determining compositional characteristics.

    Science.gov (United States)

    Commeau, R.F.; Reynolds, Leslie A.; Poag, C.W.

    1985-01-01

    The composition of agglutinated foraminiferal tests vary remarkably in response to local substrate characteristics, physiochemical properties of the water column and species- dependant selectivity of test components. We have employed a technique that combines a scanning electron microscope with an energy dispersive X-ray spectrometer system to identify major and minor elemental constituents of agglutinated foraminiferal walls. As a sample is bombarded with a beam of high energy electrons, X-rays are generated that are characteristic of the elements present. As a result, X- ray density maps can be produced for each of several elements present in the tests of agglutinated foraminifers. -Authors

  1. Statistical Energy Analysis (SEA) and Energy Finite Element Analysis (EFEA) Predictions for a Floor-Equipped Composite Cylinder

    Science.gov (United States)

    Grosveld, Ferdinand W.; Schiller, Noah H.; Cabell, Randolph H.

    2011-01-01

    Comet Enflow is a commercially available, high frequency vibroacoustic analysis software founded on Energy Finite Element Analysis (EFEA) and Energy Boundary Element Analysis (EBEA). Energy Finite Element Analysis (EFEA) was validated on a floor-equipped composite cylinder by comparing EFEA vibroacoustic response predictions with Statistical Energy Analysis (SEA) and experimental results. Statistical Energy Analysis (SEA) predictions were made using the commercial software program VA One 2009 from ESI Group. The frequency region of interest for this study covers the one-third octave bands with center frequencies from 100 Hz to 4000 Hz.

  2. Arbuscular mycorrhizal fungi affect glucosinolate and mineral element composition in leaves of Moringa oleifera.

    Science.gov (United States)

    Cosme, Marco; Franken, Philipp; Mewis, Inga; Baldermann, Susanne; Wurst, Susanne

    2014-10-01

    Moringa is a mycorrhizal crop cultivated in the tropics and subtropics and appreciated for its nutritive and health-promoting value. As well as improving plant mineral nutrition, arbuscular mycorrhizal fungi (AMF) can affect plant synthesis of compounds bioactive against chronic diseases in humans. Rhizophagus intraradices and Funneliformis mosseae were used in a full factorial experiment to investigate the impact of AMF on the accumulation of glucosinolates, flavonoids, phenolic acids, carotenoids, and mineral elements in moringa leaves. Levels of glucosinolates were enhanced, flavonoids and phenolic acids were not affected, levels of carotenoids (including provitamin A) were species-specifically reduced, and mineral elements were affected differently, with only Cu and Zn being increased by the AMF. This study presents novel results on AMF effects on glucosinolates in leaves and supports conclusions that the impacts of these fungi on microelement concentrations in edible plants are species dependent. The nonspecific positive effects on glucosinolates and the species-specific negative effects on carotenoids encourage research on other AMF species to achieve general benefits on bioactive compounds in moringa.

  3. Anti-inflammatory effect of elemental diets with different fat composition in experimental colitis.

    Science.gov (United States)

    Papada, E; Kaliora, A C; Gioxari, A; Papalois, A; Forbes, A

    2014-04-14

    The aim of the present study was to evaluate the effectiveness of two isoenergetic elemental formulae with different fat content in the rat model of trinitrobenzene sulphonic acid (TNBS) colitis that mimics human inflammatory bowel disease. A total of forty-five male Wistar rats were assigned to five groups: (1) control group; (2) TNBS-induced colitis group; (3) TNBS-induced colitis group fed a long-chain TAG (LCT)-rich diet; (4) TNBS-induced colitis group fed a medium-chain TAG (MCT)-rich diet; (5) TNBS-induced colitis group fed a baseline diet and administered infliximab. Nutritional management lasted 12 d before and 4 d after rectal administration of TNBS. Subsequently, the rats were killed, and colonic tissue samples were collected for the assessment of histology, inflammation and oxidative stress. The MCT-rich diet decreased IL-6, IL-8 and intercellular adhesion molecule-1 (ICAM-1) levels and glutathione S-transferase (GST) activity, while the LCT-rich diet reduced only ICAM-1 levels and GST activity (P<0.05). Neither elemental formula affected IL-10 levels. Infliximab reduced IL-8 and ICAM-1 levels and GST activity and increased IL-10 levels (P<0.05). No significant differences were detected in oxidative stress. Histological damage scores differed significantly only between the control and the TNBS-induced colitis group. A MCT-rich formula seems to exert stronger anti-inflammatory effects than a LCT-rich formula in TNBS colitis.

  4. Performance of hybrid cement composite elements under drop-weight impact load

    Directory of Open Access Journals (Sweden)

    Nguyen, V. D.

    2014-05-01

    Full Text Available The performance, under drop-weight impact load, of hybrid cement composite (HCC elements, consisting of a top layer of plain concrete (PC and a bottom layer of fibre reinforced concrete (FRC, in comparison with full-depth FRC and PC was studied. Apart from improving the tensile capacity of PC and saving fibre steel reinforcements of FRC, the results showed that HCC can effectively control the deformations and enhance the impact performance of the structural members as its outcomes were similar to that of a full-depth FRC. The analytical studies using Hughes empirical formulae (HEF and yield line theory (YLT adopted to investigate the practical use of HCC showed that they are applicable for design such HCC elements against impacts.Se estudió el comportamiento, frente a impacto de torre de caída, de elementos híbridos base cemento (HCC, formados por una capa superior de hormigón en masa (PC y una capa inferior de hormigón reforzado con fibras (FRC en comparación con elementos análogos íntegramente fabricados con FRC y PC. Además de proporcionar una mejora en la resistencia frente a flexo-tracción de los PC y un ahorro en refuerzo usando fibras de acero en el caso de los FRC, los resultados mostraron que el HCC puede controlar eficazmente las deformaciones y mejorar el rendimiento frente a impacto de los elementos estructurales ya que sus resultados fueron análogos a la de los FRC. Los estudios analíticos, utilizando HEF e YLT, adoptados para investigar el uso práctico de los HCC mostraron que los mismos son aplicables para el diseño de estos elementos frente a impacto.

  5. Skeletal growth dynamics linked to trace-element composition in the scleractinian coral Pocillopora damicornis

    Science.gov (United States)

    Brahmi, Chloe; Kopp, Christophe; Domart-Coulon, Isabelle; Stolarski, Jarosław; Meibom, Anders

    2012-12-01

    The micro- and ultra-structural skeletal growth dynamics of the scleractinian coral Pocillopora damicornis (Linnaeus 1758) was studied with pulsed 86Sr-labeling and high spatial resolution NanoSIMS isotopic imaging. Average extension rates for the two basic ultra-structural components of the skeleton, Rapid Accretion Deposits (RAD) and Thickening Deposits (TD), were compared between corallite wall, spines and dissepiments. The RAD, forming the basal part of the dissepiment, were found to form extremely fast compared with RAD and TD in other parts of the skeleton. Trace element compositions (i.e., Mg/Ca and Sr/Ca ratios) obtained for each ultra-structural component reveal the full range of chemical variation on the scale of the individual corallite. The Mg/Ca ratio was found to vary about a factor of 6, from ˜2.2 mmol/mol in slow growing ornamental spines to ˜13 mmol/mol in the fast forming dissepiment RAD. A positive relationship between Mg/Ca and inferred average extension rate was observed. Sr/Ca, on the other hand, although it varies substantially in the range between ˜6.5 and ˜9.5 mmol/mol, does not show any relationship with inferred average extension rate, nor does is correlate with the Mg/Ca ratio. Rayleigh fractionation models are not capable of explaining the trace element variations. The results presented in this study imply that the coral is capable of controlling its biomineralization activity with great temporal and spatial precision. Spatial heterogeneity in coral tissue activity should be carefully investigated in the development of biomineralization models for scleractinian corals.

  6. Long-term aerosol measurements in Gran Canaria, Canary Islands: Particle concentration, sources and elemental composition

    Science.gov (United States)

    Gelado-Caballero, MaríA. D.; López-GarcíA, Patricia; Prieto, Sandra; Patey, Matthew D.; Collado, Cayetano; HéRnáNdez-Brito, José J.

    2012-02-01

    There are very few sets of long-term measurements of aerosol concentrations over the North Atlantic Ocean, yet such data is invaluable in quantifying atmospheric dust inputs to this ocean region. We present an 8-year record of total suspended particles (TSP) collected at three stations on Gran Canaria Island, Spain (Taliarte at sea level, Tafira 269 m above sea level (a.s.l.) and Pico de la Gorra 1930 m a.s.l.). Using wet and dry deposition measurements, the mean dust flux was calculated at 42.3 mg m-2 d-1. Air mass back trajectories (HYSPLIT, NOAA) suggested that the Sahara desert is the major source of African dust (dominant during 32-50% of days), while the Sahel desert was the major source only 2-10% of the time (maximum in summer). Elemental composition ratios of African samples indicate that, despite the homogeneity of the dust in collected samples, some signatures of the bedrocks can still be detected. Differences were found for the Sahel, Central Sahara and North of Sahara regions in Ti/Al, Mg/Al and Ca/Al ratios, respectively. Elements often associated with pollution (Pb, Cd, Ni, Zn) appeared to share a common origin, while Cu may have a predominantly local source, as suggested by a decrease in the enrichment factor (EF) of Cu during dust events. The inter-annual variability of dust concentrations is investigated in this work. During winter, African dust concentration measurements at the Pico de la Gorra station were found to correlate with the North Atlantic Oscillation (NAO) index.

  7. The origin and evolution of chondrites recorded in the elemental and isotopic compositions of their macromolecular organic matter

    Science.gov (United States)

    Alexander, C. M. O.'D.; Fogel, M.; Yabuta, H.; Cody, G. D.

    2007-09-01

    Extraterrestrial organic matter in meteorites potentially retains a unique record of synthesis and chemical/thermal modification by parent body, nebular and even presolar processes. In a survey of the elemental and isotopic compositions of insoluble organic matter (IOM) from 75 carbonaceous, ordinary and enstatite chondrites, we find dramatic variations within and between chondrite classes. There is no evidence that these variations correlate with the time and/or location of chondrite formation, or with any primary petrologic or bulk compositional features that are associated with nebular processes (e.g., chondrule and volatile trace element abundances). Nor is there evidence for the formation of the IOM by Fischer-Tropsch-Type synthesis in the nebula or in the parent bodies. The elemental variations are consistent with thermal maturation and/or oxidation of a common precursor. For reasons that are unclear, there are large variations in isotopic composition within and between chondrite classes that do not correlate in a simple way with elemental composition or petrologic type. Nevertheless, because of the pattern of elemental variations with petrologic type and the lack of any correlation with the primary features of the chondrite classes, at present the most likely explanation is that all IOM compositional variations are the result of parent body processing of a common precursor. If correct, the range of isotopic compositions within and between chondrite classes implies that the IOM is composed of several isotopically distinct components whose relative stability varied with parent body conditions. The most primitive IOM is found in the CR chondrites and Bells (CM2). Isotopically, the IOM from these meteorites resembles the IOM in interplanetary dust particles. Chemically, their IOM resembles the CHON particles of comet Halley. Despite the large isotopic anomalies in the IOM from these meteorites, it is uncertain whether the IOM formed in the interstellar medium or

  8. A Nonlinear Finite Element Method for Magnetoelectric Composite and the Study on the Influence of Interfacial Bonding

    Directory of Open Access Journals (Sweden)

    He-Ling Wang

    2013-01-01

    Full Text Available Magnetoelectric composite material is effective in transferring magnetic field into electric signal. In this paper, a nonlinear finite element method is present to model the magnetoelectric composite of ferroelectric and magnetostrictive material. In the method, the nonlinear and coupling behavior of magnetostrictive material such as Terfenol-D is considered. The nonuniform magnetic, electric, and mechanical field distributions are present. An interfacial transferring coefficient is defined to investigate the performance of interfacial mechanical coupling quantitatively, and the influence of the properties of interfacial bonding material and interfacial cracks on magnetoelectric coefficient is discussed. A new laminate ME composite of curved interface is proposed to overcome weak interfacial bonding.

  9. Finite Element Analysis of the Random Response Suppression of Composite Panels at Elevated Temperatures using Shape Memory Alloy Fibers

    Science.gov (United States)

    Turner, Travis L.; Zhong, Z. W.; Mei, Chuh

    1994-01-01

    A feasibility study on the use of shape memory alloys (SMA) for suppression of the random response of composite panels due to acoustic loads at elevated temperatures is presented. The constitutive relations for a composite lamina with embedded SMA fibers are developed. The finite element governing equations and the solution procedures for a composite plate subjected to combined acoustic and thermal loads are presented. Solutions include: 1) Critical buckling temperature; 2) Flat panel random response; 3) Thermal postbuckling deflection; 4) Random response of a thermally buckled panel. The preliminary results demonstrate that the SMA fibers can completely eliminate the thermal postbuckling deflection and significantly reduce the random response at elevated temperatures.

  10. Root canal filling: fracture strength of fiber-reinforced composite-restored roots and finite element analysis.

    Science.gov (United States)

    Rippe, Marília Pivetta; Santini, Manuela Favarin; Bier, Carlos Alexandre Souza; Borges, Alexandre Luiz Souto; Valandro, Luiz Felipe

    2013-01-01

    The aims of this study were to evaluate the effect of root canal filling techniques on root fracture resistance and to analyze, by finite element analysis (FEA), the expansion of the endodontic sealer in two different root canal techniques. Thirty single-rooted human teeth were instrumented with rotary files to a standardized working length of 14 mm. The specimens were embedded in acrylic resin using plastic cylinders as molds, and allocated into 3 groups (n=10): G(lateral) - lateral condensation; G(single-cone) - single cone; G(tagger) - Tagger's hybrid technique. The root canals were prepared to a length of 11 mm with the #3 preparation bur of a tapered glass fiber-reinforced composite post system. All roots received glass fiber posts, which were adhesively cemented and a composite resin core was built. All groups were subjected to a fracture strength test (1 mm/min, 45°). Data were analyzed statistically by one-way ANOVA with a significance level of 5%. FEA was performed using two models: one simulated lateral condensation and Tagger's hybrid technique, and the other one simulated the single-cone technique. The second model was designed with an amount of gutta-percha two times smaller and a sealer layer two times thicker than the first model. The results were analyzed using von Mises stress criteria. One-way ANOVA indicated that the root canal filling technique affected the fracture strength (p=0.004). The G(lateral) and G(tagger) produced similar fracture strength values, while G(single-cone) showed the lowest values. The FEA showed that the single-cone model generated higher stress in the root canal walls. Sealer thickness seems to influence the fracture strength of restored endodontically treated teeth.

  11. The global elemental composition of 433 Eros: First results from the NEAR gamma-ray spectrometer orbital dataset

    Science.gov (United States)

    Peplowski, Patrick N.

    2016-12-01

    A primary goal of the Near-Earth Asteroid Rendezvous (NEAR) mission was to compare the elemental composition of the S-type asteroid 433 Eros to the chemical compositions of meteorites, with the specific objective of testing the hypothesis that the S-type asteroids are the source of the ordinary chondrite (OC) meteorites. To that end, NEAR carried an X-ray and Gamma-ray Spectrometer (XGRS) to measure the elemental composition of Eros from orbit. To date, no Eros-originating signal had been reported in GRS orbital measurements, a consequence of NEAR's high orbital altitudes about Eros. A reanalysis of the NEAR GRS orbital dataset, particularly data collected during a series of low-altitude flyovers, has finally revealed the first positively identified gamma-ray signals from Eros. This dataset, which amounts to just 10 h of data collection, was used to produce the first GRS-derived global elemental composition values. Results include the first absolute concentrations of Fe and Th, and the first global K concentration. The data confirm prior conclusions that the elemental composition of Eros' surface is inconsistent with achondritic and volatile-rich carbonaceous chondritic compositions. In contrast, ordinary chondrites, volatile-poor carbonaceous chondrites, and enstatite chondrites have compositions that are consistent with Eros' gamma-ray emissions. When placed in the context of other gamma-ray spectrometer investigations, this analysis indicates that successful gamma-ray spectroscopy investigations require extended periods of time (≥10 days) at orbital altitudes less than or equal to the radius of the target body.

  12. "EFFECT OF PROGESTOGEN-ONLY CONTRACEPTIVES ON HUMAN MILK COMPOSITION"

    Directory of Open Access Journals (Sweden)

    Sh. Ghazizadeh P. Pasalar

    2004-08-01

    Full Text Available Different contraceptive methods are used by breastfeeding mothers. To investigate the effects of progestogen - only contraceptives on human milk components, a non-randomized, follow-up study was carried out in Iran (Varamin on 140 breastfeeding women, 51 of whom used progestogenonly contraception including progestogen-only pills (POP or depo-medroxyprogesterone acetate (DMPA, and 89 used non-hormonal contraception methods, starting at 6 weeks after delivery. Human milk components were compared between the groups after 26 weeks. There were no statistically significant differences between groups, in terms of protein, sodium, calcium, phosphorus and potassium concentration of milk, but triglycerides in the hormonal group and magnesium in the non-hormonal group were higher than the other group (P< 0.05. It seems that progestogen-only methods (POP and DMPA do not have an adverse effect on human milk composition, and are safe contraceptives during lactation.

  13. HUMAN AND MARE'S MILK - PROTEIN FRACTION AND LIPID COMPOSITION

    Directory of Open Access Journals (Sweden)

    Vesna Gantner

    2014-12-01

    Full Text Available In human population if the infants are not breast-fed, a substitute for breast milk is nee¬ded. Use of cow's milk can induce allergies during the first 3 years of life. Alternative could be mare's milk. The objectives of this review were to compare human and mare's milk protein fraction and lipid composition as well as to determine adequacy of mare's milk as substitute for breast milk. Similarities are found regarding the protein and salt content; whey protein and NPN concentrations; structure of protein micelles and lipid globules; proportion of saturated fatty acids and unsaturated fatty acids. Taking into account determined similarities of human and mare's milk, it could be concluded that mare's milk is suitable nourishment for infants.

  14. Trace element composition and cathodoluminescence of kyanite and its petrogenetic implications

    Science.gov (United States)

    Müller, Axel; van den Kerkhof, Alfons M.; Selbekk, Rune S.; Broekmans, Maarten A. T. M.

    2016-09-01

    Kyanite crystals from fourteen localities worldwide were analysed for their abundances of the trace elements Na, Mg, K, Ca, Ti, V, Cr, Mn, and Fe and cathodoluminescence (CL) properties. Based on protolith type, metamorphic setting, and distinctive trace element fingerprints, a genetic classification of kyanite-bearing rocks is suggested: (A) Al-rich metasediments which commonly contain coarse-grained quartz-kyanite segregations; (B) metamorphosed granitic rocks, specifically granulites; (C) metamorphosed argillic alteration zones hosted originally in felsic igneous rocks; (D) metamorphosed argillic alteration zones hosted originally in mafic igneous rocks; and (E) metamorphosed mafic to ultramafic rocks, specifically eclogites. Vanadium and Cr concentrations reflect both protolith and host rock compositions and therefore may provide a geochemical fingerprint for the nature of the protolith. The incorporation of Fe into kyanite is largely controlled by oxygen fugacity during kyanite formation, and therefore, in most cases, its concentration cannot be related to that of the protolith. From our results, Ti concentration appears to be related to metamorphic grade, particularly formation temperature. If proven by further studies, Ti-in-kyanite may provide a useful geothermometer. Correlation of trace element abundances with CL spectra confirms that common red CL, which is composed of the spectral bands centred at 1.69 eV (734 nm), 1.75 eV (708 nm), and 1.80 eV (689 nm), is related to Cr3+ defects. CL spectra of most kyanites show in addition a low-intensity blue emission centred at 2.56 eV (485 nm). Correlation of the intensity of the blue emission with Ti suggests that it is related to or sensitized by Ti4+ or Ti3+ defects. Kyanites with >3200 µgg-1 Fe show generally no detectable CL due to the CL-quenching effect of Fe2+. Our findings provide new criteria in the exploration for and quality assessment of new kyanite deposits. The Ti content, one of the critical

  15. Calculation of the effective thermal properties of the composites based on the finite element solutions of the boundary value problems

    Science.gov (United States)

    Vdovichenko, I. I.; Yakovlev, M. Ya; Vershinin, A. V.; Levin, V. A.

    2016-11-01

    One of the key problems of mechanics of composite materials is an estimation of effective properties of composite materials. This article describes the algorithms for numerical evaluation of the effective thermal conductivity and thermal expansion of composites. An algorithm of effective thermal conductivity evaluation is based on sequential solution of boundary problems of thermal conductivity with different boundary conditions (in the form of the temperature on the boundary) on representative volume element (RVE) of composite with subsequent averaging of the resulting vector field of heat flux. An algorithm of effective thermal expansion evaluation is based on the solution of the boundary problem of elasticity (considering the thermal expansion) on a RVE of composite material with subsequent averaging of a resulting strain tensor field. Numerical calculations were performed with the help of Fidesys Composite software module of CAE Fidesys using the finite element method. The article presents the results of numerical calculations of the effective coefficients of thermal conductivity and thermoelasticity for two types of composites (single-layer fiber and particulate materials) in comparison with the analytical estimates. The comparison leads to the conclusion about the correctness of algorithms and program developed.

  16. Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

    Science.gov (United States)

    Futa, K.; Stern, C.R.

    1988-01-01

    Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

  17. Experiments on Lunar Core Composition: Phase Equilibrium Analysis of A Multi-Element (Fe-Ni-S-C) System

    Science.gov (United States)

    Go, B. M.; Righter, K.; Danielson, L.; Pando, K.

    2015-01-01

    Previous geochemical and geophysical experiments have proposed the presence of a small, metallic lunar core, but its composition is still being investigated. Knowledge of core composition can have a significant effect on understanding the thermal history of the Moon, the conditions surrounding the liquid-solid or liquid-liquid field, and siderophile element partitioning between mantle and core. However, experiments on complex bulk core compositions are very limited. One limitation comes from numerous studies that have only considered two or three element systems such as Fe-S or Fe-C, which do not supply a comprehensive understanding for complex systems such as Fe-Ni-S-Si-C. Recent geophysical data suggests the presence of up to 6% lighter elements. Reassessments of Apollo seismological analyses and samples have also shown the need to acquire more data for a broader range of pressures, temperatures, and compositions. This study considers a complex multi-element system (Fe-Ni-S-C) for a relevant pressure and temperature range to the Moon's core conditions.

  18. Amphiboles as indicators of mantle source contamination: Combined evaluation of stable H and O isotope compositions and trace element ratios

    NARCIS (Netherlands)

    Demény, A.; Harangi, S.; Vennemann, T.W.; Casillas, R.; Horváth, P.; Milton, A.J.; Mason, P.R.D.; Ulianov, A.

    2012-01-01

    Stable isotope and trace element compositions of igneous amphiboles from different tectonic settings (ocean island basalts, intraplate alkaline basalts, subduction-related andesitic complexes) were compiled to help understand the role of fluids and melts in subduction-related mantle metasomatism

  19. Rare earths and trace elements contents in leaves: A new indicator of the composition of atmospheric dust.

    Science.gov (United States)

    Censi, P; Cibella, F; Falcone, E E; Cuttitta, G; Saiano, F; Inguaggiato, C; Latteo, V

    2017-02-01

    The relationship between the trace element distribution in atmospheric particles and leaves of some exposed plants in the environment was recently demonstrated. This indication would suggest that the trace element analysis of leaves in these plants could provide information about the composition, nature and origin of the atmospheric dust dispersed in the environment. In order to corroborate this hypothesis, the distribution of trace elements and Rare Earths were studied in leaves of some endemic plants, in the atmospheric fallout and in soils of rural, urban and industrial ecosystems in Sicily. These elements have been chosen to discriminate the source and nature of different source on atmospheric dust and the larger capability of the composition of the latter materials to influence the metal ion distribution in leaves of studied plants rather than the soil composition. These evidences are related to the recognition both of positive La anomaly and trace element enrichments in studied leaves and to their particular V/Th and Co/Ni signature. On the other hand, some particular normalised REE features recognised in leaves suggest that a limited contribution to the REE budget in studied leaves is provided by the REE migration from roots.

  20. Cognitive neuroscience in forensic science: understanding and utilizing the human element.

    Science.gov (United States)

    Dror, Itiel E

    2015-08-01

    The human element plays a critical role in forensic science. It is not limited only to issues relating to forensic decision-making, such as bias, but also relates to most aspects of forensic work (some of which even take place before a crime is ever committed or long after the verification of the forensic conclusion). In this paper, I explicate many aspects of forensic work that involve the human element and therefore show the relevance (and potential contribution) of cognitive neuroscience to forensic science. The 10 aspects covered in this paper are proactive forensic science, selection during recruitment, training, crime scene investigation, forensic decision-making, verification and conflict resolution, reporting, the role of the forensic examiner, presentation in court and judicial decisions. As the forensic community is taking on the challenges introduced by the realization that the human element is critical for forensic work, new opportunities emerge that allow for considerable improvement and enhancement of the forensic science endeavour.

  1. Cognitive neuroscience in forensic science: understanding and utilizing the human element

    Science.gov (United States)

    Dror, Itiel E.

    2015-01-01

    The human element plays a critical role in forensic science. It is not limited only to issues relating to forensic decision-making, such as bias, but also relates to most aspects of forensic work (some of which even take place before a crime is ever committed or long after the verification of the forensic conclusion). In this paper, I explicate many aspects of forensic work that involve the human element and therefore show the relevance (and potential contribution) of cognitive neuroscience to forensic science. The 10 aspects covered in this paper are proactive forensic science, selection during recruitment, training, crime scene investigation, forensic decision-making, verification and conflict resolution, reporting, the role of the forensic examiner, presentation in court and judicial decisions. As the forensic community is taking on the challenges introduced by the realization that the human element is critical for forensic work, new opportunities emerge that allow for considerable improvement and enhancement of the forensic science endeavour. PMID:26101281

  2. Particle Morphology and Elemental Composition of Smoke Generated by Overheating Common Spacecraft Materials

    Science.gov (United States)

    Meyer, Marit E.

    2015-01-01

    Fire safety in the indoor spacecraft environment is concerned with a unique set of fuels which are designed to not combust. Unlike terrestrial flaming fires, which often can consume an abundance of wood, paper and cloth, spacecraft fires are expected to be generated from overheating electronics consisting of flame resistant materials. Therefore, NASA prioritizes fire characterization research for these fuels undergoing oxidative pyrolysis in order to improve spacecraft fire detector design. A thermal precipitator designed and built for spacecraft fire safety test campaigns at the NASA White Sands Test Facility (WSTF) successfully collected an abundance of smoke particles from oxidative pyrolysis. A thorough microscopic characterization has been performed for ten types of smoke from common spacecraft materials or mixed materials heated at multiple temperatures using the following techniques: SEM, TEM, high resolution TEM, high resolution STEM and EDS. Resulting smoke particle morphologies and elemental compositions have been observed which are consistent with known thermal decomposition mechanisms in the literature and chemical make-up of the spacecraft fuels. Some conclusions about particle formation mechanisms are explored based on images of the microstructure of Teflon smoke particles and tar ball-like particles from Nomex fabric smoke.

  3. A geometrically nonlinear shell element for hygrothermorheologically simple linear viscoelastic composites

    Energy Technology Data Exchange (ETDEWEB)

    HAMMERAND,DANIEL C.; KAPANIA,RAKESH K.

    2000-05-01

    A triangular flat shell element for large deformation analysis of linear viscoelastic laminated composites is presented. Hygrothermorheologically simple materials are considered for which a change in the hygrothermal environment results in a horizontal shifting of the relaxation moduli curves on a log time scale, in addition to the usual hygrothermal loads. Recurrence relations are developed and implemented for the evaluation of the viscoelastic memory loads. The nonlinear deformation process is computed using an incremental/iterative approach with the Newton-Raphson Method used to find the incremental displacements in each step. The presented numerical examples consider the large deformation and stability of linear viscoelastic structures under deformation-independent mechanical loads, deformation-dependent pressure loads, and thermal loads. Unlike elastic structures that have a single critical load value associated with a given snapping of buckling instability phenomenon, viscoelastic structures will usually exhibit a particular instability for a range of applied loads over a range of critical times. Both creep buckling and snap-through examples are presented here. In some cases, viscoelastic results are also obtained using the quasielastic method in which load-history effects are ignored, and time-varying viscoelastic properties are simply used in a series of elastic problems. The presented numerical examples demonstrate the capability and accuracy of the formulation.

  4. Changing compositions in the Iceland plume; Isotopic and elemental constraints from the Paleogene Faroe flood basalts

    DEFF Research Database (Denmark)

    Søager, Nina; Holm, Paul Martin

    2011-01-01

    -type component similar in geochemistry to the Icelandic Öræfajökull lavas. This component is believed to be recycled pelagic sediments in the plume but it can alternatively be a local crustal or lithospheric mantle component. The enriched Faroe high-Ti lavas erupted inland from the rift have isotopic......Elemental and Sr, Nd, Hf and high precision Pb isotopic data are presented from 59 low-Ti and high-Ti lavas from the syn-break up part of the Faroe Flood Basalt Province. The depleted MORB-like low-Ti lavas erupted in the rift zone between the Faroe Islands and central East Greenland around...... the time of break up of the North Atlantic have isotopic end-member compositions different from the depleted Iceland lavas. We suggest that the main low-Ti mantle component is NAEM (North Atlantic End-Member (Ellam and Stuart, 2000, J. Petrol. 41, 919) and that the 207Pb/204Pb value of the component should...

  5. Experimental Characterization of Ionic Polymer Metal Composite as a Novel Fractional Order Element

    Directory of Open Access Journals (Sweden)

    Riccardo Caponetto

    2013-01-01

    Full Text Available Ionic polymer metal composites (IPMCs are electroactive materials made of ionic polymer thin membranes with platinum metallization on their surfaces. They are interesting materials due to not only their electromechanical applications as transducers but also to their electrochemical features and the relationship between the ionic/solvent current and the potential field. Their electrochemical properties thus suggest the possibility for exploiting them as compact fractional-order elements (FOEs with a view of defining fabrication processes and production strategies that assure the desired performances. In this paper, the experimental electrical characterization of a brand new IPMC setup in a fixed sandwich configuration is proposed. Two IPMC devices with different platinum absorption times (5 h and 20 h are characterized through experimental data: first, a preliminary linearity study is performed for a fixed input voltage amplitude in order to determine the frequency region where IPMC can be approximated as linear; then, a frequency analysis is carried out in order to identify a coherent fractional-order dynamics in the bode diagrams. Such analyses take the first steps towards a simplified model of IPMC as a compact electronic FOE for which the fractional exponent value depends on fabrication parameters as the absorption time.

  6. Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

    Science.gov (United States)

    Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

    2016-02-01

    The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

  7. Failure Test and Finite Element Simulation of a Large Wind Turbine Composite Blade under Static Loading

    Directory of Open Access Journals (Sweden)

    Xiao Chen

    2014-04-01

    Full Text Available This study presented a failure analysis of a 52.3 m composite wind turbine blade under static loading. Complex failure characteristics exhibited at the transition region of the blade were thoroughly examined and typical failure modes were indentified. In order to predict multiple failure modes observed in the tests and gain more insights into the failure mechanisms of the blade, a Finite Element (FE simulation was performed using a global-local modeling approach and Progressive Failure Analysis (PFA techniques which took into account material failure and property degradation. Failure process and failure characteristics of the transition region were satisfactorily reproduced in the simulation, and it was found that accumulated delamination in spar cap and shear web failure at the transition region were the main reasons for the blade to collapse. Local buckling played an important role in the failure process by increasing local out-of-plane deformation, while the Brazier effect was found not to be responsible for the blade failure.

  8. Calibration of Discrete Element Heat Transfer Parameters by Central Composite Design

    Science.gov (United States)

    Deng, Zongquan; Cui, Jinsheng; Hou, Xuyan; Jiang, Shengyuan

    2017-03-01

    The efficiency and precision of parameter calibration in discrete element method (DEM) are not satisfactory, and parameter calibration for granular heat transfer is rarely involved. Accordingly, parameter calibration for granular heat transfer with the DEM is studied. The heat transfer in granular assemblies is simulated with DEM, and the effective thermal conductivity (ETC) of these granular assemblies is measured with the transient method in simulations. The measurement testbed is designed to test the ETC of the granular assemblies under normal pressure and a vacuum based on the steady method. Central composite design (CCD) is used to simulate the impact of the DEM parameters on the ETC of granular assemblies, and the heat transfer parameters are calibrated and compared with experimental data. The results show that, within the scope of the considered parameters, the ETC of the granular assemblies increases with an increasing particle thermal conductivity and decreases with an increasing particle shear modulus and particle diameter. The particle thermal conductivity has the greatest impact on the ETC of granular assemblies followed by the particle shear modulus and then the particle diameter. The calibration results show good agreement with the experimental results. The error is less than 4%, which is within a reasonable range for the scope of the CCD parameters. The proposed research provides high efficiency and high accuracy parameter calibration for granular heat transfer in DEM.

  9. Evaluation of Test Methods for Triaxially Braided Composites using a Meso-Scale Finite Element Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao

    2015-10-01

    The characterization of triaxially braided composite is complicate due to the nonuniformity of deformation within the unit cell as well as the possibility of the freeedge effect related to the large size of the unit cell. Extensive experimental investigation has been conducted to develop more accurate test approaches in characterizing the actual mechanical properties of the material we are studying. In this work, a meso-scale finite element model is utilized to simulate two complex specimens: notched tensile specimen and tube tensile specimen, which are designed to avoid the free-edge effect and free-edge effect induced premature edge damage. The full field strain data is predicted numerically and compared with experimental data obtained by Digit Image Correlation. The numerically predicted tensile strength values are compared with experimentally measured results. The discrepancy between numerically predicted and experimentally measured data, the capability of different test approaches are analyzed and discussed. The presented numerical model could serve as assistance to the evaluation of different test methods, and is especially useful in identifying potential local damage events.

  10. Finite Element Analysis of Composite Joint Configurations with Gaps and Overlaps

    Science.gov (United States)

    Krueger, Ronald

    2014-01-01

    The goal of the current study is to identify scenarios for which thermal and moisture effects become significant in the loading of a composite structure. In the current work, a simple configuration was defined, and material properties were selected. A Fortran routine was created to automate the mesh generation process. The routine was used to create the models for the initial mesh refinement study. A combination of element length and width suitable for further studies was identified. Also, the effect of the overlap length and gap length on computed shear and through-thickness stresses along the bondline of the joints was studied for the mechanical load case. Further, the influence of neighboring gaps and overlaps on these joint stresses was studied and was found to be negligible. The results suggest that for an initial study it is sufficient to focus on one configuration with fixed overlap and gap lengths to study the effects of mechanical, thermal and moisture loading and combinations thereof on computed joint stresses

  11. Biogenic Aerosols Over the Amazon Basin: Optical Properties and Relationship With Elemental and Ionic Composition

    Science.gov (United States)

    Artaxo, P.; Martin, S. T.; Andreae, M. O.; Godoy, J. M.; Godoy, M. L.; Rizzo, L. V.; Paixao, M.

    2008-12-01

    We investigated the optical properties of natural biogenic aerosol particles over the central Amazon Basin near Manaus during the wet season in February and March 2008. The measurements were conducted as part of the AMAZE-08 (Amazonian Aerosol Characterization Experiment) sampling campaign. Light absorption was determined with the use of an Aethalometer and an MAAP (Multi Angle Absorption Photometer). Light scattering was measured with a 3 wavelength TSI nephelometer and an Ecotech nephelometer. The elemental composition was measured trough PIXE and IC. Single scattering albedo shows relatively low values varying from 0.86 to 0.95. Very low fine mode aerosol mass was measured, and coarse mode particles are responsible for a significant fraction of scattering and absorption. Sulfur was observed in very low concentrations, and most of the aerosol mass was organic. Long range transport of soil dust from Sahara were observed and reflected in the light scattering coefficient. Wavelength dependence of absorption indicates the strong influence of coarse mode aerosol. Aerosol optical thickness shows low values, but with significant single scattering albedo values, showing strong absorption properties of these biogenic aerosols. Size distribution measurements shows consistence with the scattering coefficients measured, if the coarse mode particles are taken into account.

  12. Finite element crash simulations of the human body: Passive and active muscle modelling

    Indian Academy of Sciences (India)

    S Mukherjee; A Chawla; B Karthikeyan; A Soni

    2007-08-01

    Conventional dummy based testing procedures suffer from known limitations. This report addresses issues in finite element human body models in evaluating pedestrian and occupant crash safety measures. A review of material properties of soft tissues and characterization methods show a scarcity of material properties for characterizing soft tissues in dynamic loading. Experiments imparting impacts to tissues and subsequent inverse finite element mapping to extract material properties are described. The effect of muscle activation due to voluntary and non-voluntary reflexes on injuries has been investigated through finite element modelling.

  13. Assessment of Human Organism's Intake of Trace Elements from Staple Foodstuffs in Central Region of Russia

    CERN Document Server

    Gorbunov, A V; Okina, O I; Frontasyeva, M A; Gundorina, S F

    2004-01-01

    The trace element content of raw materials and foodstuffs produced from them, typical for basket of goods of residents of Central Russia, was examined. An excess of permissible levels of some trace elements was observed. This phenomenon is explained in terms of different factors such as pollution of the environment, industrial technologies, biological peculiarities of raw materials of animal and vegetable origin. An assessment of human organism's trace element intake of different food allowances is given. This study was undertaken in the framework of IAEA CRP (Contract No. 11927/R2).

  14. Trace elements during primordial plexiform network formation in human cerebral organoids

    Directory of Open Access Journals (Sweden)

    Rafaela C. Sartore

    2017-02-01

    Full Text Available Systematic studies of micronutrients during brain formation are hindered by restrictions to animal models and adult post-mortem tissues. Recently, advances in stem cell biology have enabled recapitulation of the early stages of human telencephalon development in vitro. In the present work, we analyzed cerebral organoids derived from human pluripotent stem cells by synchrotron radiation X-ray fluorescence in order to measure biologically valuable micronutrients incorporated and distributed into the exogenously developing brain. Our findings indicate that elemental inclusion in organoids is consistent with human brain tissue and involves P, S, K, Ca, Fe and Zn. Occurrence of different concentration gradients also suggests active regulation of elemental transmembrane transport. Finally, the analysis of pairs of elements shows interesting elemental interaction patterns that change from 30 to 45 days of development, suggesting short- or long-term associations, such as storage in similar compartments or relevance for time-dependent biological processes. These findings shed light on which trace elements are important during human brain development and will support studies aimed to unravel the consequences of disrupted metal homeostasis for neurodevelopmental diseases, including those manifested in adulthood.

  15. Concentration of trace elements in human semen and relation to spermatozoa quality.

    Science.gov (United States)

    Slivkova, Jana; Popelkova, Miroslava; Massanyi, Peter; Toporcerova, Silvia; Stawarz, Robert; Formicki, Grzegorz; Lukac, Norbert; Putała, Aldona; Guzik, Marek

    2009-03-01

    In this study the concentrations of trace elements such as lead, cadmium, iron, nickel, copper and zinc in the human semen (n = 47), occurrence of pathological spermatozoa, and correlations of these elements to pathological forms were investigated. For each sample of human spermatozoa at least 500 spermatozoa were evaluated. Metal contents were determined by the voltametric method and flame absorption spectrophotometry method. The concentrations of trace elements in human semen were: lead 1.49 +/- 0.40 mg x kg(- 1), cadmium 0.13 +/- 0.15 mg x kg(- 1), iron 2.59 +/- 0.21 mg x kg(- 1), nickel 0.40 +/- 0.07 mg x kg(- 1), copper 0.28 +/- 0.06 mg x kg(- 1), and zinc 153.93 +/- 67.08 mg x kg(- 1), respectively. The total percentage of pathological spermatozoa was 41.61 +/- 9.80% with predominancy of broken flagellum, flagellum torso and separated flagellum. In relation to trace elements the analysis showed correlation between copper and lead (r = -0.47), nickel and iron (r = 0.36), lead and flagellum ball (r = -0.39), cadmium and large heads (r = 0.37) and between iron and other forms of pathological spermatozoa (r = -0.32). Results of this study describe possible effects of trace elements on the spermatozoa quality in normal human sperm.

  16. [Development and validation of a finite element model of human knee joint for dynamic analysis].

    Science.gov (United States)

    Li, Haiyan; Gu, Yulong; Ruan, Shijie; Cui, Shihai

    2012-02-01

    Based on the biomechanical response of human knee joint to a front impact in occupants accidents, a finite element (FE) model of human knee joint was developed by using computer simulation technique for impacting. The model consists of human anatomical structure, including femoral condyle, tibia condyle, fibular small head, patellar, cartilage, meniscus and primary ligament. By comparing the results of the FE model with experiments of the knee joint in axial load conditions, the validation of the model was verified. Furthermore, this study provides data for the mechanical of human knee joint injury, and is helpful for the design and optimization of the vehicle protective devices.

  17. Bioactive potential of Vitis labrusca L. grape juices from the Southern Region of Brazil: phenolic and elemental composition and effect on lipid peroxidation in healthy subjects.

    Science.gov (United States)

    Toaldo, Isabela Maia; Cruz, Fernanda Alves; Alves, Tatiana de Lima; de Gois, Jefferson Santos; Borges, Daniel L G; Cunha, Heloisa Pamplona; da Silva, Edson Luiz; Bordignon-Luiz, Marilde T

    2015-04-15

    Grapes are rich in polyphenols with biologically active properties. Although the bioactive potential of grape constituents are frequently reported, the effects of Brazilian Vitis labrusca L. grape juices ingestion have not been demonstrated in humans. This study identified the phenolic and elemental composition of red and white grape juices and the effect of organic and conventional red grape juice consumption on lipid peroxidation in healthy individuals. Concentrations of anthocyanins, flavanols and phenolic acids and the in vitro antioxidant activity were significantly higher in the organic juice. The macro-elements K, Ca, Na and Mg were the most abundant minerals in all juices. The acute consumption of red grape juices promoted significant decrease of lipid peroxides in serum and TBARS levels in plasma. It is concluded that red V. labrusca L. grape juices produced in Southern Brazil showed lipid peroxidation inhibition abilities in healthy subjects, regardless of the cultivation system.

  18. Investigation of the content and of the distribution of chemical elements in human nails by SRXRF.

    Science.gov (United States)

    Trunova, V A; Brenner, N V; Zvereva, V V

    2009-01-01

    The purpose of this investigation is to analyze 20 nails in individuals (and several persons) for the definition of how chemical elements distribute from nail to nail. The aim was to determine whether it will be rightful to take only one nail for the elemental analysis for the diagnostic of human state in future or not? Another purpose of the research is to analyze the elemental content of nails in temporal dynamic (in several persons). Analytical determinations of 20 nails of nine donors (healthy persons), nails of both hands and both feet were carried out. The analysis was performed by SRXRF. Symmetry of the elemental distribution in nails of right and left hands and right and left feet was found. The analysis of the distribution of chemical elements on the total area of a nail (55 points) was performed. The nail cutaway reflects adequately the distribution of several chemical elements over the nail plate area. In this study the elemental concentrations in nails of three donors in a 6-month period was determined. This study found the content of the chemical elements in donors' nails changes with time, individually.

  19. Stable isotope composition of human fingernails from Slovakia

    Energy Technology Data Exchange (ETDEWEB)

    Grolmusová, Zuzana, E-mail: zuzana.grolmusova@geology.sk [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Rapčanová, Anna [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); Michalko, Juraj; Čech, Peter [State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia); Veis, Pavel [Comenius University in Bratislava, Faculty of Mathematics, Physics and Informatics, Department of Experimental Physics, Mlynská dolina F2, 842 48 Bratislava (Slovakia); State Geological Institute of Dionýz Štúr, Laboratory of Isotope Geology, Mlynská dolina 1, 817 04 Bratislava (Slovakia)

    2014-10-15

    Stable isotope composition of human fingernails has proven to be useful for documenting human dietary information and geographical patterns in archeological, forensic, anthropological and biological studies. Therefore, it is of interest to detect all factors influencing the stable isotopic composition in the certain regions in the world. Carbon and nitrogen isotope data of human fingernail keratin from 52 individuals from Slovakia were reported in this study. The online combustion and continuous flow isotope-ratio mass spectrometer Delta V Advantage was used for δ{sup 13}C and δ{sup 15}N analysis of fingernail keratin samples from 24 vegetarian and 28 omnivorous individuals. A group of people with frequent meat consumption showed enrichment in {sup 13}C and {sup 15}N isotopes in fingernails. A similar trend was observed with increasing seafood in an individual's diet. Moreover a significant difference was revealed between smokers and nonsmokers for both δ{sup 13}C and δ{sup 15}N values. These data were compared to previously published δ{sup 13}C and δ{sup 15}N fingernail values from across the globe. This study brings new information on the stable isotope signature of individuals from Slovakia and characterizes the Central European region for the first time. The stable isotope composition of fingernails is influenced by the frequency of meat and seafood consumption as well as smoking. - Highlights: • This study deals with stable isotope analyses of fingernails from Slovak volunteers. • δ{sup 13}C and δ{sup 15}N values of vegetarian and omnivore fingernails were compared. • Influence of sex, diet and smoking was studied.

  20. A comparison of 100 human genes using an alu element-based instability model.

    Directory of Open Access Journals (Sweden)

    George W Cook

    Full Text Available The human retrotransposon with the highest copy number is the Alu element. The human genome contains over one million Alu elements that collectively account for over ten percent of our DNA. Full-length Alu elements are randomly distributed throughout the genome in both forward and reverse orientations. However, full-length widely spaced Alu pairs having two Alus in the same (direct orientation are statistically more prevalent than Alu pairs having two Alus in the opposite (inverted orientation. The cause of this phenomenon is unknown. It has been hypothesized that this imbalance is the consequence of anomalous inverted Alu pair interactions. One proposed mechanism suggests that inverted Alu pairs can ectopically interact, exposing both ends of each Alu element making up the pair to a potential double-strand break, or "hit". This hypothesized "two-hit" (two double-strand breaks potential per Alu element was used to develop a model for comparing the relative instabilities of human genes. The model incorporates both 1 the two-hit double-strand break potential of Alu elements and 2 the probability of exon-damaging deletions extending from these double-strand breaks. This model was used to compare the relative instabilities of 50 deletion-prone cancer genes and 50 randomly selected genes from the human genome. The output of the Alu element-based genomic instability model developed here is shown to coincide with the observed instability of deletion-prone cancer genes. The 50 cancer genes are collectively estimated to be 58% more unstable than the randomly chosen genes using this model. Seven of the deletion-prone cancer genes, ATM, BRCA1, FANCA, FANCD2, MSH2, NCOR1 and PBRM1, were among the most unstable 10% of the 100 genes analyzed. This algorithm may lay the foundation for comparing genetic risks posed by structural variations that are unique to specific individuals, families and people groups.

  1. Finite Element Analysis of the Effect of Proximal Contour of Class II Composite Restorations on Stress Distribution

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Moghaddas

    2013-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the effect of proximal contour of class II composite restorations placed with straight or contoured matrix band using composite resins with different modulus of elasticity on stress distribution by finite element method. Methods: In order to evaluate the stress distribution of class II composite restorations using finite element method, upper right first molar and second premolar were modeled. Proximal boxes were designed and restored with universal Z250 and packable P60 composite resins (3M ESPE using two matrix systems: flat Tofflemire matrix and precurved sectional matrix. Finally models were evaluated under loads of 200 and 400 Newton at 90 degrees angle and the results were graphically illustrated in the form of Von Misses stresses. Results: In general the stress obtained under 400 Newton load was significantly greater than the stress of models under 200 Newton load. Von Misses stress distribution pattern of two different Z250 and P60 composites were very similar in all modes of loading and proximal contour. In all analyzed models there was a significant difference between models restored with Tofflemire matrix with flat contour and models restored with sectional matrix with curved contour. This difference was greater in first molar than second premolar. Conclusion: Use of a contoured matrix band results in less stress in class II composite resin restorations.

  2. Finite Element Analysis of the Effect of Proximal Contour of Class II Composite Restorations on Stress Distribution

    Directory of Open Access Journals (Sweden)

    Hossein Abachizadeh

    2012-09-01

    Full Text Available Introduction: The aim of this study was to evaluate the effect of proximal contour of class II composite restorations placed with straight or contoured matrix band using composite resins with different modulus of elasticity on stress distribution by finite element method. Methods: In order to evaluate the stress distribution of class II composite restorations using finite element method, upper right first molar and second premolar were modeled. Proximal boxes were designed and restored with universal Z250 and packable P60 composite resins (3M ESPE using two matrix systems: flat Tofflemire matrix and precurved sectional matrix. Finally models were evaluated under loads of 200 and 400 Newton at 90 degrees angle and the results were graphically illustrated in the form of Von Misses stresses. Results: In general the stress obtained under 400 Newton load was significantly greater than the stress of models under 200 Newton load. Von Misses stress distribution pattern of two different Z250 and P60 composites were very similar in all modes of loading and proximal contour. In all analyzed models there was a significant difference between models restored with Tofflemire matrix with flat contour and models restored with sectional matrix with curved contour. This difference was greater in first molar than second premolar. Conclusion: Use of a contoured matrix band results in less stress in class II composite resin restorations.

  3. Importance of the elemental composition in brachytherapy with neutrons; Importancia de la composicion elemental en braquiterapia con neutrones

    Energy Technology Data Exchange (ETDEWEB)

    Paredes G, L.; Balcazar G, M. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Azorin N, J. [UAM-I, 09340 Mexico D.F. (Mexico); Francois L, J.L. [ICN-UNAM, 04510 Mexico D.F. (Mexico)

    2004-07-01

    An analysis is presented of as the small differences that exist in the elementary composition of the wicked tumors, healthy fabrics and some material substitutes of fabric employees in dosimetry, they generate variations in the value of the kerma coefficient and consequently in the absorbed dose of neutrons in the interval 11 eV to 29 MeV. These differences make that the coefficient of kerma of neutrons average for the considered wicked tumors, be between 6% and 7% smaller that the coefficient of kerma of neutrons average for soft fabric, in the interval of interest in therapy with quick neutrons. These results have a special importance during the process of planning of brachytherapy treatments with sources of {sup 252} Cf, to optimize and to individualize the treatments to the patients. (Author)

  4. The influence of the ketogenic diet on the elemental and biochemical compositions of the hippocampal formation.

    Science.gov (United States)

    Chwiej, Joanna; Skoczen, Agnieszka; Matusiak, Katarzyna; Janeczko, Krzysztof; Patulska, Agnieszka; Sandt, Christophe; Simon, Rolf; Ciarach, Malgorzata; Setkowicz, Zuzanna

    2015-08-01

    A growing body of evidence demonstrates that dietary therapies, mainly the ketogenic diet, may be highly effective in the reduction of epileptic seizures. All of them share the common characteristic of restricting carbohydrate intake to shift the predominant caloric source of the diet to fat. Catabolism of fats results in the production of ketone bodies which become alternate energy substrates to glucose. Although many mechanisms by which ketone bodies yield its anticonvulsant effect are proposed, the relationships between the brain metabolism of the ketone bodies and their neuroprotective and antiepileptogenic action still remain to be discerned. In the study, X-ray fluorescence microscopy and FTIR microspectroscopy were used to follow ketogenic diet-induced changes in the elemental and biochemical compositions of rat hippocampal formation tissue. The use of synchrotron sources of X-rays and infrared allowed us to examine changes in the accumulation and distribution of selected elements (P, S, K, Ca, Fe, Cu, Zn, and Se) and biomolecules (proteins, lipids, ketone bodies, etc.) with the micrometer spatial resolution. The comparison of rats fed with the ketogenic diet and rats fed with the standard laboratory diet showed changes in the hippocampal accumulation of P, K, Ca, and Zn. The relations obtained for Ca (increased level in CA3, DG, and its internal area) and Zn (decreased areal density in CA3 and DG) were analogous to those that we previously observed for rats in the acute phase of pilocarpine-induced seizures. Biochemical analysis of tissues taken from ketogenic diet-fed rats demonstrated increased intensity of absorption band occurring at 1740 cm(-1), which was probably the result of elevated accumulation of ketone bodies. Moreover, higher absolute and relative (3012 cm(-1)/2924 cm(-1), 3012 cm(-1)/lipid massif, and 3012 cm(-1)/amide I) intensity of the 3012-cm(-1) band resulting from increased unsaturated fatty acids content was found after the treatment

  5. Elemental composition of natural nanoparticles and fine colloids in European forest stream waters and their role as phosphorus carriers

    DEFF Research Database (Denmark)

    Gottselig, N.; Amelung, W.; Kirchner, J. W.

    2017-01-01

    Biogeochemical cycling of elements largely occurs in dissolved state, but many elements may also be bound to natural nanoparticles (NNP, 1–100 nm) and fine colloids (100-450 nm). We examined the hypothesis that the size and composition of stream water NNP and colloids vary systematically across...... Europe. To test this hypothesis, 96 stream water samples were simultaneously collected in 26 forested headwater catchments along two transects across Europe. Three size fractions (~1–20 nm, >20–60 nm, >60 nm) of NNP and fine colloids were identified with Field Flow Fractionation coupled to inductively...... coupled plasma mass-spectrometry and an organic carbon detector. The results showed that NNP and fine colloids constituted between 2±5% (Si) and 53±21% (Fe; mean ± SD) of total element concentrations, indicating a substantial contribution of particles to element transport in these European streams...

  6. Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the southern Andes

    Energy Technology Data Exchange (ETDEWEB)

    Futa, Kiyoto; Stern, C.R.

    1988-05-01

    Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46/sup 0/S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54/sup 0/S) range for /sup 87/Sr//sup 86/Sr from 0.70280 to 0.70591 and for /sup 143/Nd//sup 144/Nd from 0.51314 to 0.51255. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have /sup 87/Sr//sup 86/Sr, /sup 143/Nd//sup 144/Nd, La/Yb, Ba/La and Hf/Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35/sup 0/S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33/sup 0/ and 34/sup 0/S, basaltic andesites and andesites have higher /sup 87/Sr//sup 86/Sr, Rb/Cs, and Hf/Lu, and lower /sup 143/Nd//sup 144/Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54/sup 0/S) has Sr and Nd isotopic compositions and K/Rb and Ba/La similar to MORB. The high La/Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO/sub 2/, K/sub 2/O, Rb, Ba, Ba/La, and /sup 87/Sr//sup 86/Sr and decrease in MgO, Sr, K/Rb, Rb/Cs, and /sup 143/Nd//sup 144/Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra-crustal contamination. (orig./SHOE).

  7. Repetitive elements may comprise over two-thirds of the human genome.

    Directory of Open Access Journals (Sweden)

    A P Jason de Koning

    2011-12-01

    Full Text Available Transposable elements (TEs are conventionally identified in eukaryotic genomes by alignment to consensus element sequences. Using this approach, about half of the human genome has been previously identified as TEs and low-complexity repeats. We recently developed a highly sensitive alternative de novo strategy, P-clouds, that instead searches for clusters of high-abundance oligonucleotides that are related in sequence space (oligo "clouds". We show here that P-clouds predicts >840 Mbp of additional repetitive sequences in the human genome, thus suggesting that 66%-69% of the human genome is repetitive or repeat-derived. To investigate this remarkable difference, we conducted detailed analyses of the ability of both P-clouds and a commonly used conventional approach, RepeatMasker (RM, to detect different sized fragments of the highly abundant human Alu and MIR SINEs. RM can have surprisingly low sensitivity for even moderately long fragments, in contrast to P-clouds, which has good sensitivity down to small fragment sizes (∼25 bp. Although short fragments have a high intrinsic probability of being false positives, we performed a probabilistic annotation that reflects this fact. We further developed "element-specific" P-clouds (ESPs to identify novel Alu and MIR SINE elements, and using it we identified ∼100 Mb of previously unannotated human elements. ESP estimates of new MIR sequences are in good agreement with RM-based predictions of the amount that RM missed. These results highlight the need for combined, probabilistic genome annotation approaches and suggest that the human genome consists of substantially more repetitive sequence than previously believed.

  8. Primary magmas and mantle sources of Emeishan basalts constrained from major element, trace element and Pb isotope compositions of olivine-hosted melt inclusions

    Science.gov (United States)

    Ren, Zhong-Yuan; Wu, Ya-Dong; Zhang, Le; Nichols, Alexander R. L.; Hong, Lu-Bing; Zhang, Yin-Hui; Zhang, Yan; Liu, Jian-Qiang; Xu, Yi-Gang

    2017-07-01

    Olivine-hosted melt inclusions within lava retain important information regarding the lava's primary magma compositions and mantle sources. Thus, they can be used to infer the nature of the mantle sources of large igneous provinces, which is still not well known and of the subject of debate. We have analysed the chemical compositions and Pb isotopic ratios of olivine-hosted melt inclusions in the Dali picrites, Emeishan Large Igneous Province (LIP), SW China. These are the first in-situ Pb isotope data measured for melt inclusions found in the Emeishan picrites and allow new constraints to be placed on the source lithology of the Emeishan LIP. The melt inclusions show chemical compositional variations, spanning low-, intermediate- and high-Ti compositions, while their host whole rocks are restricted to the intermediate-Ti compositions. Together with the relatively constant Pb isotope ratios of the melt inclusions, the compositional variations suggest that the low-, intermediate- and high-Ti melts were derived from compositionally similar sources. The geochemical characteristics of melt inclusions, their host olivines, and whole-rocks from the Emeishan LIP indicate that Ca, Al, Mn, Yb, and Lu behave compatibly, and Ti, Rb, Sr, Zr, and Nb behave incompatibly during partial melting, requiring a pyroxenite source for the Emeishin LIP. The wide range of Ti contents in the melt inclusions and whole-rocks of the Emeishan basalts reflects different degrees of partial melting in the pyroxenite source at different depths in the melting column. The Pb isotope compositions of the melt inclusions and the OIB-like trace element compositions of the Emeishan basalts imply that mixing of a recycled ancient oceanic crust (EM1-like) component with a peridotite component from the lower mantle (FOZO-like component) could have underwent solid-state reaction, producing a secondary pyroxenite source that was subsequently partially melted to form the basalts. This new model of pyroxenite

  9. Low-Velocity Impact Response and Finite Element Analysis of Four-Step 3-D Braided Composites

    Science.gov (United States)

    Sun, Baozhong; Zhang, Yan; Gu, Bohong

    2013-08-01

    The low-velocity impact characters of 3-D braided carbon/epoxy composites were investigated from experimental and finite element simulation approaches. The quasi-static tests were carried out at a constant velocity of 2 mm/min on MTS 810.23 material tester system to obtain the indentation load-displacement curves and indentation damages. The low-velocity tests were conducted at the velocities from 1 m/s to 6 m/s (corresponding to the impact energy from 3.22 J to 116 J) on Instron Dynatup 9250 impact tester. The peak force, energy for peak force, time to peak force, and total energy absorption were obtained to determine the impact responses of 3-D braided composites. A unit cell model was established according to the microstructure of 3-D braided composites to derive the constitutive equation. Based on the model, a user-defined material subroutine (VUMAT) has been compiled by FORTRAN and connected with commercial finite element code ABAQUS/Explicit to calculate the impact damage. The unit cell model successfully predicted the impact response of 3-D braided composites. Furthermore, the stress wave propagation and failure mechanisms have been revealed from the finite element simulation results and ultimate damage morphologies of specimens.

  10. An evaluation of a coupled microstructural approach for the analysis of functionally graded composites via the finite-element method

    Science.gov (United States)

    Pindera, Marek-Jerzy; Dunn, Patrick

    1995-01-01

    A comparison is presented between the predictions of the finite-element analysis and a recently developed higher-order theory for functionally graded materials subjected to a thorough-thickness temperature gradient. In contrast to existing micromechanical theories that utilize classical (i.e., uncoupled) homogenization schemes to calculate micro-level and macro-level stress and displacement fields in materials with uniform or nonuniform fiber spacing (i.e., functionally graded materials), the new theory explicitly couples the microstructural details with the macrostructure of the composite. Previous thermo-elastic analysis has demonstrated that such coupling is necessary when: the temperature gradient is large with respect to the dimension of the reinforcement; the characteristic dimension of the reinforcement is large relative to the global dimensions of the composite and the number of reinforcing fibers or inclusions is small. In these circumstances, the standard micromechanical analyses based on the concept of the representative volume element used to determine average composite properties produce questionable results. The comparison between the predictions of the finite-element method and the higher-order theory presented herein establish the theory's accuracy in predicting thermal and stress fields within composites with a finite number of fibers in the thickness direction subjected to a thorough-thickness thermal gradient.

  11. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure

    Science.gov (United States)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter

    2014-01-01

    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  12. Human Learning of Elemental Category Structures: Revising the Classic Result of Shepard, Hovland, and Jenkins (1961)

    Science.gov (United States)

    Kurtz, Kenneth J.; Levering, Kimery R.; Stanton, Roger D.; Romero, Joshua; Morris, Steven N.

    2013-01-01

    The findings of Shepard, Hovland, and Jenkins (1961) on the relative ease of learning 6 elemental types of 2-way classifications have been deeply influential 2 times over: 1st, as a rebuke to pure stimulus generalization accounts, and again as the leading benchmark for evaluating formal models of human category learning. The litmus test for models…

  13. Automated volumetric grid generation for finite element modeling of human hand joints

    Energy Technology Data Exchange (ETDEWEB)

    Hollerbach, K.; Underhill, K. [Lawrence Livermore National Lab., CA (United States); Rainsberger, R. [XYZ Scientific Applications, Inc., Livermore, CA (United States)

    1995-02-01

    We are developing techniques for finite element analysis of human joints. These techniques need to provide high quality results rapidly in order to be useful to a physician. The research presented here increases model quality and decreases user input time by automating the volumetric mesh generation step.

  14. Examining the Impact of Culture and Human Elements on OLAP Tools Usefulness

    Science.gov (United States)

    Sharoupim, Magdy S.

    2010-01-01

    The purpose of the present study was to examine the impact of culture and human-related elements on the On-line Analytical Processing (OLAP) usability in generating decision-making information. The use of OLAP technology has evolved rapidly and gained momentum, mainly due to the ability of OLAP tools to examine and query large amounts of data sets…

  15. Can experimental data in humans verify the finite element-based bone remodeling algorithm?

    DEFF Research Database (Denmark)

    Wong, Christian; Gehrchen, P Martin; Kiaer, Thomas

    2008-01-01

    A finite element analysis-based bone remodeling study in human was conducted in the lumbar spine operated on with pedicle screws. Bone remodeling results were compared to prospective experimental bone mineral content data of patients operated on with pedicle screws....

  16. Composition of human skin microbiota affects attractiveness to malaria mosquitoes.

    Directory of Open Access Journals (Sweden)

    Niels O Verhulst

    Full Text Available The African malaria mosquito Anopheles gambiae sensu stricto continues to play an important role in malaria transmission, which is aggravated by its high degree of anthropophily, making it among the foremost vectors of this disease. In the current study we set out to unravel the strong association between this mosquito species and human beings, as it is determined by odorant cues derived from the human skin. Microbial communities on the skin play key roles in the production of human body odour. We demonstrate that the composition of the skin microbiota affects the degree of attractiveness of human beings to this mosquito species. Bacterial plate counts and 16S rRNA sequencing revealed that individuals that are highly attractive to An. gambiae s.s. have a significantly higher abundance, but lower diversity of bacteria on their skin than individuals that are poorly attractive. Bacterial genera that are correlated with the relative degree of attractiveness to mosquitoes were identified. The discovery of the connection between skin microbial populations and attractiveness to mosquitoes may lead to the development of new mosquito attractants and personalized methods for protection against vectors of malaria and other infectious diseases.

  17. Raman measurement of carotenoid composition in human skin

    Science.gov (United States)

    Ermakov, Igor V.; Ermakova, Maia R.; Gellermann, Werner

    2004-07-01

    The carotenoids lycopene and beta-carotene are powerful antioxidants in skin and are thought to act as scavengers for free radicals and singlet oxygen. The role of carotenoid species in skin health is of strong current interest. We demonstrate the possibility to use Resonance Raman spectroscopy for fast, non-invasive, highly specific, and quantitative detection of beta-carotene and lycopene in human skin. Analyzing Raman signals originating from the carbon-carbon double bond stretch vibrations of the carotenoid molecules under blue and green laser excitation, we were able to characterize quantitatively the relative concentrations of each carotenoid species in-vivo. In the selective detection, we take advantage of different Raman cross-section spectral profiles for beta-carotene and lycopene molecules, and obtain a quantitative assessment of individual long-chain carotenoid species in the skin rather than their cumulative levels. Preliminary dual-wavelength Raman measurements reveal significant differences in the carotenoid composition of different subjects. The technique holds promise for rapid screening of carotenoid compositions in human skin in large populations and may be suitable in clinical studies for assessing the risk for cutaneous diseases.

  18. Identification of topographic elements composition based on landform boundaries from radar interferometry segmentation (preliminary study on digital landform mapping)

    Science.gov (United States)

    Widyatmanti, Wirastuti; Wicaksono, Ikhsan; Dinta Rahma Syam, Prima

    2016-06-01

    Dense vegetation that covers most landscapes in Indonesia becomes a common limitation in mapping the landforms in tropical region. This paper aims to examine the use of radar interferometry for landform mapping in tropical region; to examine the application of segmentation method to develop landform type boundaries; and to identify the topographic elements composition for each type of landform. Using Idrisi® and “eCognition ®” softwares, toposhape analysis, segmentation and multi-spectral classification were applied to identify the composition of topographic elements i.e. the types of land-cover from Landsat 8, elevation, slope, relief intensity and curvatures from SRTM (DEM). Visual interpretation on DEM and land-cover fusion imagery was conducted to derive basic control maps of landform and land-cover. The result shows that in segmentation method, shape and compactness levels are essential in obtaining land-cover, elevation, and slope class units to determine the most accurate class borders of each element. Despite a complex procedure applied in determining landform classification, the combination of topographic elements segmentation result presents a distinct border of each landform class. The comparison between landform maps derived from segmentation process and visual interpretation method demonstrates slight dissimilarities, meaning that multi-stage segmentation approach can improve and provide more effective digital landform mapping method in tropical region. Topographic elements on each type of landforms show distinctive composition key containing the percentage of each curvature elements per area unit. Supported by GIS programming and modeling in the future, this finding is significant in reducing effort in landform mapping using visual interpretation method for a very large coverage but in detail scale level.

  19. Carbon allocation and element composition in four Chlamydomonas mutants defective in genes related to the CO2 concentrating mechanism.

    Science.gov (United States)

    Memmola, Francesco; Mukherjee, Bratati; Moroney, James V; Giordano, Mario

    2014-09-01

    Four mutants of Chlamydomonas reinhardtii with defects in different components of the CO2 concentrating mechanism (CCM) or in Rubisco activase were grown autotrophically at high pCO2 and then transferred to low pCO2, in order to study the role of different components of the CCM on carbon allocation and elemental composition. To study carbon allocation, we measured the relative size of the main organic pools by Fourier Transform Infrared spectroscopy. Total reflection X-ray fluorescence was used to analyze the elemental composition of algal cells. Our data show that although the organic pools increased their size at high CO2 in all strains, their stoichiometry was highly homeostatic, i.e., the ratios between carbohydrates and proteins, lipid and proteins, and carbohydrates and lipids, did not change significantly. The only exception was the wild-type 137c, in which proteins decreased relative to carbohydrates and lipids, when the cells were transferred to low CO2. It is noticeable that the two wild types used in this study responded differently to the transition from high to low CO2. Malfunctions of the CCM influenced the concentration of several elements, somewhat altering cell elemental stoichiometry: especially the C/P and N/P ratios changed appreciably in almost all strains as a function of the growth CO2 concentration, except in 137c and the Rubisco activase mutant rca1. In strain cia3, defective in the lumenal carbonic anhydrase (CA), the cell quotas of P, S, Ca, Mn, Fe, and Zn were about 5-fold higher at low CO2 than at high CO2. A Principle Components Analysis showed that, mostly because of its elemental composition, cia3 behaved in a substantially different way from all other strains, at low CO2. The lumenal CA thus plays a crucial role, not only for the correct functioning of the CCM, but also for element utilization. Not surprisingly, growth at high CO2 attenuated differences among strains.

  20. THE COMPOSITION OF INTERSTELLAR GRAINS TOWARD ζ OPHIUCHI: CONSTRAINING THE ELEMENTAL BUDGET NEAR THE DIFFUSE-DENSE CLOUD TRANSITION

    Energy Technology Data Exchange (ETDEWEB)

    Poteet, Charles A.; Whittet, Douglas C. B. [New York Center for Astrobiology, Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Draine, Bruce T., E-mail: charles.poteet@gmail.com [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)

    2015-03-10

    We investigate the composition of interstellar grains along the line of sight toward ζ Ophiuchi, a well-studied environment near the diffuse-dense cloud transition. A spectral decomposition analysis of the solid-state absorbers is performed using archival spectroscopic observations from the Spitzer Space Telescope and Infrared Space Observatory. We find strong evidence for the presence of sub-micron-sized amorphous silicate grains, principally comprised of olivine-like composition, with no convincing evidence of H{sub 2}O ice mantles. However, tentative evidence for thick H{sub 2}O ice mantles on large (a ≈ 2.8 μm) grains is presented. Solid-state abundances of elemental Mg, Si, Fe, and O are inferred from our analysis and compared to standard reference abundances. We find that nearly all of the Mg and Si atoms along the line of sight reside in amorphous silicate grains, while a substantial fraction of the elemental Fe resides in compounds other than silicates. Moreover, we find that the total abundance of elemental O is largely inconsistent with the adopted reference abundances, indicating that as much as ∼156 ppm of interstellar O is missing along the line of sight. After taking into account additional limits on the abundance of elemental O in other O-bearing solids, we conclude that any missing reservoir of elemental O must reside on large grains that are nearly opaque to infrared radiation.

  1. Correlations of trace elements in breast human tissues: Evaluation of spatial distribution using {mu}-XRF

    Energy Technology Data Exchange (ETDEWEB)

    Piacenti da Silva, Marina; Silva, Deisy Mara da; Ribeiro-Silva, Alfredo; Poletti, Martin Eduardo [Departamento de Fisica, FFCLRP/USP, Av. dos Bandeirantes n. 3900, 14040-901 Ribeirao Preto - SP (Brazil); Departamento de Patologia, HCFM/USP, Av. dos Bandeirantes n. 3900, 14040-901 Ribeirao Preto - SP (Brazil); Departamento de Fisica, FFCLRP/USP, Av. dos Bandeirantes n. 3900, 14040-901 Ribeirao Preto - SP (Brazil)

    2012-05-17

    The aim of this work is to investigate microscopic correlations between trace elements in breast human tissues. A synchrotron X-ray fluorescence microprobe system ({mu}-XRF) was used to obtain two-dimensional distribution of trace element Ca, Fe, Cu and Zn in normal (6 samples) and malignant (14 samples) breast tissues. The experiment was performed in X-ray Fluorescence beam line at Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, Brazil. The white microbeam was generated with a fine conical capillary with a 20 {mu}m output diameter. The samples were supported on a XYZ table. An optical microscope with motorized zoom was used for sample positioning and choice the area to be scanned. Automatic two-dimensional scans were programmed and performed with steps of 30 {mu}m in each direction (x, y) on the selected area. The fluorescence signals were recorded using a Si(Li) detector, positioned at 90 degrees with respect to the incident beam, with a collection time of 10 s per point. The elemental maps obtained from each sample were overlap to observe correlation between trace elements. Qualitative results showed that the pairs of elements Ca-Zn and Fe-Cu could to be correlated in malignant breast tissues. Quantitative results, achieved by Spearman correlation tests, indicate that there is a spatial correlation between these pairs of elements (p < 0.001) suggesting the importance of these elements in metabolic processes associated with the development of the tumor.

  2. Element content analysis by WDXRF in pistachios grown under organic and conventional farming regimes for human nutrition and health.

    Science.gov (United States)

    Akbaba, Ugur; Sahin, Yusuf; Türkez, Hasan

    2012-10-01

    In this investigation, the elemental composition of various Antep pistachios (Pistacia vera L.) samples was determined using a sensitive method called wavelength dispersive x-ray fluorescence (WDXRF). A total of 27 elements, such as Al, As, Bi, Ca, Cd, Cu, Fe, Mn, Ni, P, S, Sr, Zn, Cl, Pb, K, Mg, Na, Ba, Rb, Si, Br, Sn, Au, La, Ti and Zr, were determined in pistachios samples (n = 10) grown under organic and conventional farming regimes. The obtained results from each group were analyzed statistically using SPSS statistic program. It was observed that the concentration and peak intensity values of Ca, Fe, Mn, P, Mg, Cl, Na and K elements were higher in the pistachios samples grown under organic farming regime. Similarly, Al was found in higher level in the samples grown under conventional farming regime. As, Bi, Cd, Pb, Ti, La, Sn and Zr contents were measured. Their contents were below the detection limits. Our findings clearly revealed that organic pistachios are likely to have higher nutritional mineral content. The pistachios samples grown under conventional farming regime could contain harmful metals like Al that might damage various systems and/or organs of humans and animals.

  3. A finite element model of the human buttocks for prediction of seat pressure distributions.

    Science.gov (United States)

    Verver, M M; van Hoof, J; Oomens, C W J; Wismans, J S H M; Baaijens, F P T

    2004-08-01

    Seating comfort is becoming increasingly important for the automotive industry. Car manufacturers use seating comfort to distinguish their products from those of competitors. However, the development and design of a new, more comfortable seat is time consuming and costly. The introduction of computer models of human and seat will accelerate this process. The contact interaction between human and seat is an important factor in the comfort sensation of subjects. This paper presents a finite element (FE) model of the human buttocks, able to predict the pressure distribution between human and seating surface by its detailed and realistic geometric description. A validation study based on volunteer experiments shows reasonable correlation in pressure distributions between the buttocks model and the volunteers. Both for simulations on a rigid and a soft cushion, the model predicts realistic seat pressure distributions. A parameter study shows that a pressure distribution at the interface between human and seat strongly depends on variations in human flesh and seat cushion properties.

  4. Population and clinical genetics of human transposable elements in the (post) genomic era

    Science.gov (United States)

    Rishishwar, Lavanya; Wang, Lu; Clayton, Evan A.; Mariño-Ramírez, Leonardo; McDonald, John F.; Jordan, I. King

    2017-01-01

    ABSTRACT Recent technological developments—in genomics, bioinformatics and high-throughput experimental techniques—are providing opportunities to study ongoing human transposable element (TE) activity at an unprecedented level of detail. It is now possible to characterize genome-wide collections of TE insertion sites for multiple human individuals, within and between populations, and for a variety of tissue types. Comparison of TE insertion site profiles between individuals captures the germline activity of TEs and reveals insertion site variants that segregate as polymorphisms among human populations, whereas comparison among tissue types ascertains somatic TE activity that generates cellular heterogeneity. In this review, we provide an overview of these new technologies and explore their implications for population and clinical genetic studies of human TEs. We cover both recent published results on human TE insertion activity as well as the prospects for future TE studies related to human evolution and health.

  5. Effects of zirconium element on the microstructure and deuterium retention of W-Zr/Sc2O3 composites.

    Science.gov (United States)

    Chen, Hongyu; Luo, Laima; Chen, Jingbo; Zan, Xiang; Zhu, Xiaoyong; Xu, Qiu; Luo, Guangnan; Chen, Junling; Wu, Yucheng

    2016-09-06

    Dense W and W-Zr composites reinforced with Sc2O3 particles were produced through powder metallurgy and subsequent spark plasma sintering (SPS) at 1700 °C and 58 MPa. Results showed that the W-1vol.%Zr/2vol.%Sc2O3 composites exhibited optimal performance with the best relative density of up to 98.93% and high Vickers microhardness of approximately 583 Hv. The thermal conductivity of W-Zr/Sc2O3 composites decreased initially and then increased as the Zr content increased. The moderate Zr alloying element could combine well with Sc2O3 particles and W grains and form a solid solution. However, excess Zr element leads to agglomeration in the grain boundaries. W-1vol.%Zr/2vol.%Sc2O3 composite had a good deuterium irradiation resistance very closing to pure tungsten compared with the other Zr element contents of composites. Under 500 K, D2 retention and release of them were similar to those of commercial tungsten, even lower between 400 K to 450 K. Pre-irradiation with 5 keV-He(+) ions to a fluence of 1 × 10(21) He(+)/m(2) resulted in an increase in deuterium retention (deuterium was implanted after He(+) irradiation), thereby shifting the desorption peak to a high temperature from 550 K to 650 K for the W-1vol.%Zr/2vol.%Sc2O3 composite.

  6. Effects of zirconium element on the microstructure and deuterium retention of W–Zr/Sc2O3 composites

    Science.gov (United States)

    Chen, Hongyu; Luo, Laima; Chen, Jingbo; Zan, Xiang; Zhu, Xiaoyong; Xu, Qiu; Luo, Guangnan; Chen, Junling; Wu, Yucheng

    2016-01-01

    Dense W and W–Zr composites reinforced with Sc2O3 particles were produced through powder metallurgy and subsequent spark plasma sintering (SPS) at 1700 °C and 58 MPa. Results showed that the W–1vol.%Zr/2vol.%Sc2O3 composites exhibited optimal performance with the best relative density of up to 98.93% and high Vickers microhardness of approximately 583 Hv. The thermal conductivity of W–Zr/Sc2O3 composites decreased initially and then increased as the Zr content increased. The moderate Zr alloying element could combine well with Sc2O3 particles and W grains and form a solid solution. However, excess Zr element leads to agglomeration in the grain boundaries. W–1vol.%Zr/2vol.%Sc2O3 composite had a good deuterium irradiation resistance very closing to pure tungsten compared with the other Zr element contents of composites. Under 500 K, D2 retention and release of them were similar to those of commercial tungsten, even lower between 400 K to 450 K. Pre-irradiation with 5 keV-He+ ions to a fluence of 1 × 1021 He+/m2 resulted in an increase in deuterium retention (deuterium was implanted after He+ irradiation), thereby shifting the desorption peak to a high temperature from 550 K to 650 K for the W–1vol.%Zr/2vol.%Sc2O3 composite. PMID:27597314

  7. An high order Mixed Interpolation Tensorial Components (MITC) shell element approach for modeling the buckling behavior of delaminated composites

    DEFF Research Database (Denmark)

    Gaiotti, Marco; Rizzo, Cesare M.; Branner, Kim

    2014-01-01

    of composite laminates of wind turbine blades, results were found valuable for the marine industry as well, because similar laminates are used for the hull shell and stiffeners. Systematic calculations were carried out to assess the effects of an embedded delamination on the buckling load, varying the size...... and through thickness position of the delamination. Different finite element modeling strategies were considered and validated against the experimental results. The one applying the 9 nodes MITC shell elements was found matching the experimental data despite failure modes were different for the two...

  8. Quality Assessment of the Physico-Mechanical and Elemental Composition of Three Pencil Grades and Eraser Types Produced in Nigeria

    Directory of Open Access Journals (Sweden)

    K. I. Omoniyi

    2014-06-01

    Full Text Available The quality assessment of the physical (pH, electrical conductivity, density, writeability, eraseability, mechanical (compression test and break strength and elemental composition of the pencil grades HB, 2B and 3B and eraser types of brand names Ben 10, Tiky 20 and the commonest White eraser in Nigerian primary school (Gummes Co. China was carried out. The diameter of the graphite part increased in the order HB Cr > Cd. Though, the levels of the trace metals and essential elements detected in the school items are below the recommended limits, regulatory measures should be directed towards maintaining the standards of school items.

  9. Finite Element Study on Performance of Piezoelectric Bimorph Cantilevers Using Porous/Ceramic 0-3 Polymer Composites

    Science.gov (United States)

    Kiran, Raj; Kumar, Anuruddh; Chauhan, Vishal S.; Kumar, Rajeev; Vaish, Rahul

    2017-09-01

    Finite element analysis of 0-3 composites made of piezoceramic particles and pores embedded in polyvinylidene difluoride (PVDF) has been carried out. The representative volume element (RVE) approach was used to calculate the effective elastic and piezoelectric properties of the periodic isotropic 0-3 piezoelectric composites. It was observed that the elastic and piezoelectric properties increased with the volume fraction of {K}_{0.475} {Na}_{0.475} {Li}_{0.05} ( {{Nb}_{0.92} {Ta}_{0.05} {Sb}_{0.03} } ){O}3 (KNLNTS) particles but decreased for the porous composites. These effective properties were further used to analyze the potential use of such bimorph cantilever beams in sensing and energy harvesting applications. Sensing voltage continuously increased for KNLNTS filled composites while for porous materials it increased up to 15% volume fraction porosity and then decreased. The same trend was also observed for the power produced by the harvester. However, the sensing voltage and power produced by harvesters made of porous composites were lower than for harvesters made of pure PVDF.

  10. Experimental Analysis of Repaired Masonry Elements with Flax-FRCM and PBO-FRCM Composites Subjected to Axial Bending Loads

    Directory of Open Access Journals (Sweden)

    Oscar A. Cevallos

    2015-11-01

    Full Text Available In the construction industry, the use of natural fabrics as a reinforcement for cement-based composites has shown great potential. The use of these sustainable composites to provide strengthening or repair old masonry structures that exhibit structural problems mainly due to a poor tensile strength of the mortar/brick joints is revealed to be a promising area of research. One of the most significant load conditions affecting the mechanical response of masonry structures occurs when axial bending loads are applied on the resistant cross-section. In this study, three different types of masonry elements were built using clay bricks and a lime-based mortar. After 28 days, the samples were subjected to concentric and eccentric compressive loads. In order to produce significant bending effects, the compressive loads were applied with large eccentricity, and a sudden failure characterized the behavior of the unreinforced masonry (URM elements. The tested masonry specimens were repaired using fabric-reinforced cementitious matrix (FRCM composites produced using bi-directional flax and polyparaphenylene benzobisoxazole (PBO fabrics. The mechanical behavior of the URM and repaired samples was compared in terms of load-displacement and moment-curvature responses. Furthermore, the results achieved using flax-FRCM composites were compared with those of using PBO-FRCM composites.

  11. Solar Ion Processing of Major Element Surface Compositions of Mature Mare Soils: Insights from Combined XPS and Analytical TEM Observations

    Science.gov (United States)

    Christoffersen, R.; Dukes, C.; Keller, L. P.; Baragiola, R.

    2012-01-01

    Solar wind ions are capable of altering the sur-face chemistry of the lunar regolith by a number of mechanisms including preferential sputtering, radiation-enhanced diffusion and sputter erosion of space weathered surfaces containing pre-existing compositional profiles. We have previously reported in-situ ion irradiation experiments supported by X-ray photoelectron spectroscopy (XPS) and analytical TEM that show how solar ions potentially drive Fe and Ti reduction at the monolayer scale as well as the 10-100 nm depth scale in lunar soils [1]. Here we report experimental data on the effect of ion irradiation on the major element surface composition in a mature mare soil.

  12. The isotope composition of selenium in chondrites constrains the depletion mechanism of volatile elements in solar system materials

    Science.gov (United States)

    Vollstaedt, Hauke; Mezger, Klaus; Leya, Ingo

    2016-09-01

    Solar nebula processes led to a depletion of volatile elements in different chondrite groups when compared to the bulk chemical composition of the solar system deduced from the Sun's photosphere. For moderately-volatile elements, this depletion primarily correlates with the element condensation temperature and is possibly caused by incomplete condensation from a hot solar nebula, evaporative loss from the precursor dust, and/or inherited from the interstellar medium. Element concentrations and interelement ratios of volatile elements do not provide a clear picture about responsible mechanisms. Here, the abundance and stable isotope composition of the moderately- to highly-volatile element Se are investigated in carbonaceous, ordinary, and enstatite chondrites to constrain the mechanism responsible for the depletion of volatile elements in planetary bodies of the inner solar system and to define a δ 82 / 78 Se value for the bulk solar system. The δ 82 / 78 Se of the studied chondrite falls are identical within their measurement uncertainties with a mean of - 0.20 ± 0.26 ‰ (2 s.d., n = 14, relative to NIST SRM 3149) despite Se abundance depletions of up to a factor of 2.5 with respect to the CI group. The absence of resolvable Se isotope fractionation rules out a kinetic Rayleigh-type incomplete condensation of Se from the hot solar nebula or partial kinetic evaporative loss on the precursor material and/or the parent bodies. The Se depletion, if acquired during partial condensation or evaporative loss, therefore must have occurred under near equilibrium conditions to prevent measurable isotope fractionation. Alternatively, the depletion and cooling of the nebula could have occurred simultaneously due to the continuous removal of gas and fine particles by the solar wind accompanied by the quantitative condensation of elements from the pre-depleted gas. In this scenario the condensation of elements does not require equilibrium conditions to avoid isotope

  13. Thermomechanical behavior of composite structure elements in extreme cryogenic environment; Comportement thermomecanique d'elements de structures composites en milieu cryogenique extreme

    Energy Technology Data Exchange (ETDEWEB)

    Alzina, A

    2005-10-15

    Cryo-magnet supports of the LHC particle accelerator are manufactured in E-glass/epoxy composite materials with textile reinforcement due to their low thermal conductivity and high specific stiffness. These supports are subjected to complexes thermal and mechanical loading which require a thorough study of their response. A multi-scale method is used in this study. It is based on two successive homogenizations in order to take into account the strong thermal dependence of elastic modulus and thermal strain of the resin on the one hand and the phonons mechanism which modifies the thermal transfer at fibres/matrix interfaces for the temperatures lower than 10 K on the other hand. At each step of this study, results of the models are validated by experimental results of thermal conductivity and elastic modulus for temperatures ranging between 4.2 K and 293 K. (author)

  14. Comparison of composite rotor blade models: A coupled-beam analysis and an MSC/NASTRAN finite-element model

    Science.gov (United States)

    Hodges, Robert V.; Nixon, Mark W.; Rehfield, Lawrence W.

    1987-01-01

    A methodology was developed for the structural analysis of composite rotor blades. This coupled-beam analysis is relatively simple to use compared with alternative analysis techniques. The beam analysis was developed for thin-wall single-cell rotor structures and includes the effects of elastic coupling. This paper demonstrates the effectiveness of the new composite-beam analysis method through comparison of its results with those of an established baseline analysis technique. The baseline analysis is an MSC/NASTRAN finite-element model built up from anisotropic shell elements. Deformations are compared for three linear static load cases of centrifugal force at design rotor speed, applied torque, and lift for an ideal rotor in hover. A D-spar designed to twist under axial loading is the subject of the analysis. Results indicate the coupled-beam analysis is well within engineering accuracy.

  15. Release to the Gas Phase of Inorganic Elements during Wood Combustion. Part 2: Influence of Fuel Composition

    DEFF Research Database (Denmark)

    van Lith, Simone Cornelia; Jensen, Peter Arendt; Frandsen, Flemming

    2008-01-01

    Combustion of wood for heat and power production may cause problems such as ash deposition, corrosion, and harmful emissions of gases and particulate matter. These problems are all directly related to the release of inorganic elements (in particular Cl, S, K, Na, Zn, and Pb) from the fuel...... to the gas phase. The aims of this study are to obtain quantitative data on the release of inorganic elements during wood combustion and to investigate the influence of fuel composition. Quantitative release data were obtained by pyrolyzing and subsequently combusting small samples of wood (~30 g) at various...... temperatures in the range of 500–1150 °C in a laboratory-scale tube reactor and by performing mass balance calculations based on the weight measurements and chemical analyses of the wood fuels and the residual ash samples. Four wood fuels with different ash contents and inorganic compositions were investigated...

  16. Multi-elemental imaging of paraffin-embedded human samples by laser-induced breakdown spectroscopy

    Science.gov (United States)

    Moncayo, S.; Trichard, F.; Busser, B.; Sabatier-Vincent, M.; Pelascini, F.; Pinel, N.; Templier, I.; Charles, J.; Sancey, L.; Motto-Ros, V.

    2017-07-01

    Chemical elements play central roles for physiological homeostasis in human cells, and their dysregulation might lead to a certain number of pathologies. Novel imaging techniques that improve the work of pathologists for tissue analysis and diagnostics are continuously sought. We report the use of Laser-Induced Breakdown Spectroscopy (LIBS) to perform multi-elemental images of human paraffin-embedded skin samples on the entire biopsy scale in a complementary and compatible way with microscope histopathological examination. A specific instrumental configuration is proposed in order to detect most of the elements of medical interest (i.e. P, Al, Mg, Na, Zn, Si, Fe, and Cu). As an example of medical application, we selected and analysed skin biopsies, including healthy skin tissue, cutaneous metastasis of melanoma, Merkel-cell carcinoma and squamous cell carcinoma. Clear distinctions in the distribution of chemical elements are observed from the different samples investigated. This study demonstrates the high complementarity of LIBS elemental imaging with conventional histopathology, opening new opportunities for any medical application involving metals.

  17. Wavelet Spectral Finite Elements for Wave Propagation in Composite Plates with Damages - Years 3-4

    Science.gov (United States)

    2014-05-23

    proposed by Timoshenko (1921) and Timoshenko and Woinowski-Krieger (1989). Gavric (1994) developed a numerical approach to model the cross section...Hence, in this section, skin is modeled as spectral plate element and the stiffener is modeled as a Timoshenko beam element and they are coupled using a...plates using a new stiffened element. Tech. Mech. 28 (3-4), 227-236. Timoshenko , S., 1921. On the correction of transverse shear deformation of the

  18. The validation and application of a finite element human head model for frontal skull fracture analysis.

    Science.gov (United States)

    Asgharpour, Z; Baumgartner, D; Willinger, R; Graw, M; Peldschus, S

    2014-05-01

    Traumatic head injuries can result from vehicular accidents, sports, falls or assaults. The current advances in computational methods and the detailed finite element models of the human head provide a significant opportunity for biomechanical study of human head injuries. The biomechanical characteristics of the human head through head impact scenarios can be studied in detail by using the finite element models. Skull fracture is one of the most frequent occurring types of head injuries. The purpose of this study is to analyse the experimental head impacts on cadavers by means of the Strasbourg University Finite Element Head Model (SUFEHM). The results of the numerical model and experimental data are compared for validation purpose. The finite element model has also been applied to predict the skull bone fracture in frontal impacts. The head model includes the scalp, the facial bone, the skull, the cerebral spinal fluid, the meninges, the cerebrum and the cerebellum. The model is used to simulate the experimental frontal head impact tests using a cylindrical padded impactor. Results of the computational simulation shows that the model correlated well with a number of experimental data and a global fracture pattern has been predicted well by the model. Therefore the presented numerical model could be used for reconstruction of head impacts in different impact conditions also the forensic application of the head model would provide a tool for investigation of the causes and mechanism of head injuries.

  19. Assessment of metabolome annotation quality: a method for evaluating the false discovery rate of elemental composition searches.

    Directory of Open Access Journals (Sweden)

    Fumio Matsuda

    Full Text Available BACKGROUND: In metabolomics researches using mass spectrometry (MS, systematic searching of high-resolution mass data against compound databases is often the first step of metabolite annotation to determine elemental compositions possessing similar theoretical mass numbers. However, incorrect hits derived from errors in mass analyses will be included in the results of elemental composition searches. To assess the quality of peak annotation information, a novel methodology for false discovery rates (FDR evaluation is presented in this study. Based on the FDR analyses, several aspects of an elemental composition search, including setting a threshold, estimating FDR, and the types of elemental composition databases most reliable for searching are discussed. METHODOLOGY/PRINCIPAL FINDINGS: The FDR can be determined from one measured value (i.e., the hit rate for search queries and four parameters determined by Monte Carlo simulation. The results indicate that relatively high FDR values (30-50% were obtained when searching time-of-flight (TOF/MS data using the KNApSAcK and KEGG databases. In addition, searches against large all-in-one databases (e.g., PubChem always produced unacceptable results (FDR >70%. The estimated FDRs suggest that the quality of search results can be improved not only by performing more accurate mass analysis but also by modifying the properties of the compound database. A theoretical analysis indicates that FDR could be improved by using compound database with smaller but higher completeness entries. CONCLUSIONS/SIGNIFICANCE: High accuracy mass analysis, such as Fourier transform (FT-MS, is needed for reliable annotation (FDR <10%. In addition, a small, customized compound database is preferable for high-quality annotation of metabolome data.

  20. The Study of Stability of Compression-Loaded Multispan Composite Panel Upon Failure of Elements Binding it to Panel Supports

    Science.gov (United States)

    Zamula, G. N.; Ierusalimsky, K. M.; Fomin, V. P.; Grishin, V. I.; Kalmykova, G. S.

    1999-01-01

    The present document is a final technical report carried out within co-operation between United States'NASA Langley RC and Russia's Goskomoboronprom in aeronautics, and continues similar programs, accomplished in 1996, 1997, and 1998, respectively). The report provides results of "The study of stability of compression-loaded multispan composite panels upon failure of elements binding it to panel supports"; these comply with requirements established at TsAGI on 24 March 1998 and at NASA on 15 September 1998.

  1. Trace Elements in Human Myocardial Infarction Determined by Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wester, P.O.

    1965-05-15

    By means of neutron activation analysis, injured and adjacent uninjured human heart tissue from 12 autopsy cases with myocardial infarction are investigated with respect to the concentration of 23 trace elements. The bulk elements K, Na and P are also determined. A recently developed ion-exchange technique, combined with subsequent y-spectrometry, is used. The following trace elements are determined: Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Rb, Sb, Sc, Se, Sm, Zn and W. In the injured tissue compared to the uninjured, calculation on a wet weight basis showed a decrease in Co, Cs, K, Mo, P, Rb and Zn, and an increase in Br, Ca, Ce, La, Na, Sb and Sm. The differences in Ca, La, Mo, P and Zn are dependent on the age of the myocardial infarction, and the regression lines for these elements are given. The concentration of the trace elements in uninjured tissue from infarcted hearts is compared to the concentration of these elements in normal heart tissue, determined in a previous study. In the uninjured tissue from infarcted hearts a decrease is found in Cu and Mo, and an increase in As and Ce.

  2. Elemental concentrations of four types of human gallstones by PIXE analysis

    Energy Technology Data Exchange (ETDEWEB)

    Suhara, M. (Department oh Hygiene and Public Health, School of Medicine, Iwate Medical Univ., Iwate (Japan)); Matsuda, K.; Sera, K.

    1998-01-01

    Elemental concentrations of human gallstones were determined by PIXE method. Gallstone samples analyzed in this report are classified into cholestrol gallstone (pure cholestrol stone and mixed stone) and pigment gallstone (black stone and calcium bilirubinate stone). The targets were prepared by paste spreading method previously reported, which enable us to determine also volatile elements, such as halogen atoms, Hg and so on, under acidic condition. Concentrations of 17 kinds of elements were determined and characteristic distributions are presented for each type of gallstone. Ca values are the highest among them in all types of gallstones. Pigment gallstones contain significantly higher concentrations of 9 kinds of elements (Na, Mg, S, Cl, Ca, Mn, Fe, Cu, Zn) than cholesterol gallstones. Concentrations of S, Fe, and Zn in black stones are significantly higher than those in calcium bilirubinate stones. Almost all elements contained in the samples can be determined by PIXE method, and it is supposed that the elements or some of them affect formation of gallstones and their pigment. Some samples of the pigment gallstones included I, Hg, and Pb. (author)

  3. Radiocarbon dating and compositional analysis of pre-Columbian human bones

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, E., E-mail: andrade@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Solís, C.; Canto, C.E.; Lucio, O.G. de [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Chavez, E. [ESIME-Z, Instituto Politécnico Nacional, ALM Zacatenco, 07738 México D.F. (Mexico); Rocha, M.F.; Villanueva, O.; Torreblanca, C.A. [Centro INAH Zacatecas, Miguel Auza No. 205, Col. Centro, Zacatecas/Zacatecas CP 98000 (Mexico)

    2014-08-01

    Analysis of ancient human bones found in “El Cóporo”, an archaeological site in Guanajuato, Mexico; were performed using a multi techniques scheme: {sup 14}C radiocarbon dating, IBA (Ion Beam Analysis), SEM-EDS (Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy). We measured the elemental composition of the bones, especially some with a superficial black pigmentation. Soil samples collected from the burial place were also analyzed. The {sup 14}C dating was performed with a new High Voltage Europe 1 MV Tandentron Accelerator Mass Spectrometer (AMS) recently installed in the IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México). The radiocarbon dating allowed us to determine the date of death of the individual in a period between the year 890 and 975 AD, which is consistent with the late period of the Cóporo civilization. The element sample analysis of bones with the surface black pigmentation show higher levels of Fe, Mn and Ba compared when bone’s black surface was mechanically removed. These three elements were found in soil samples from the skeleton burial place. These results indicate more likely that the bone black coloration is due to a postmortem alteration occurring in the burial environment.

  4. Radiocarbon dating and compositional analysis of pre-Columbian human bones

    Science.gov (United States)

    Andrade, E.; Solís, C.; Canto, C. E.; de Lucio, O. G.; Chavez, E.; Rocha, M. F.; Villanueva, O.; Torreblanca, C. A.

    2014-08-01

    Analysis of ancient human bones found in "El Cóporo", an archaeological site in Guanajuato, Mexico; were performed using a multi techniques scheme: 14C radiocarbon dating, IBA (Ion Beam Analysis), SEM-EDS (Scanning Electron Microscope Energy Dispersive X-ray Spectroscopy). We measured the elemental composition of the bones, especially some with a superficial black pigmentation. Soil samples collected from the burial place were also analyzed. The 14C dating was performed with a new High Voltage Europe 1 MV Tandentron Accelerator Mass Spectrometer (AMS) recently installed in the IFUNAM (Instituto de Física, Universidad Nacional Autónoma de México). The radiocarbon dating allowed us to determine the date of death of the individual in a period between the year 890 and 975 AD, which is consistent with the late period of the Cóporo civilization. The element sample analysis of bones with the surface black pigmentation show higher levels of Fe, Mn and Ba compared when bone's black surface was mechanically removed. These three elements were found in soil samples from the skeleton burial place. These results indicate more likely that the bone black coloration is due to a postmortem alteration occurring in the burial environment.

  5. An application of a relational database system for high-throughput prediction of elemental compositions from accurate mass values.

    Science.gov (United States)

    Sakurai, Nozomu; Ara, Takeshi; Kanaya, Shigehiko; Nakamura, Yukiko; Iijima, Yoko; Enomoto, Mitsuo; Motegi, Takeshi; Aoki, Koh; Suzuki, Hideyuki; Shibata, Daisuke

    2013-01-15

    High-accuracy mass values detected by high-resolution mass spectrometry analysis enable prediction of elemental compositions, and thus are used for metabolite annotations in metabolomic studies. Here, we report an application of a relational database to significantly improve the rate of elemental composition predictions. By searching a database of pre-calculated elemental compositions with fixed kinds and numbers of atoms, the approach eliminates redundant evaluations of the same formula that occur in repeated calculations with other tools. When our approach is compared with HR2, which is one of the fastest tools available, our database search times were at least 109 times shorter than those of HR2. When a solid-state drive (SSD) was applied, the search time was 488 times shorter at 5 ppm mass tolerance and 1833 times at 0.1 ppm. Even if the search by HR2 was performed with 8 threads in a high-spec Windows 7 PC, the database search times were at least 26 and 115 times shorter without and with the SSD. These improvements were enhanced in a low spec Windows XP PC. We constructed a web service 'MFSearcher' to query the database in a RESTful manner. Available for free at http://webs2.kazusa.or.jp/mfsearcher. The web service is implemented in Java, MySQL, Apache and Tomcat, with all major browsers supported. sakurai@kazusa.or.jp Supplementary data are available at Bioinformatics online.

  6. Characterization of elemental and structural composition of corrosion scales and deposits formed in drinking water distribution systems.

    Science.gov (United States)

    Peng, Ching-Yu; Korshin, Gregory V; Valentine, Richard L; Hill, Andrew S; Friedman, Melinda J; Reiber, Steve H

    2010-08-01

    Corrosion scales and deposits formed within drinking water distribution systems (DWDSs) have the potential to retain inorganic contaminants. The objective of this study was to characterize the elemental and structural composition of extracted pipe solids and hydraulically-mobile deposits originating from representative DWDSs. Goethite (alpha-FeOOH), magnetite (Fe(3)O(4)) and siderite (FeCO(3)) were the primary crystalline phases identified in most of the selected samples. Among the major constituent elements of the deposits, iron was most prevalent followed, in the order of decreasing prevalence, by sulfur, organic carbon, calcium, inorganic carbon, phosphorus, manganese, magnesium, aluminum and zinc. The cumulative occurrence profiles of iron, sulfur, calcium and phosphorus for pipe specimens and flushed solids were similar. Comparison of relative occurrences of these elements indicates that hydraulic disturbances may have relatively less impact on the release of manganese, aluminum and zinc, but more impact on the release of organic carbon, inorganic carbon, and magnesium.

  7. Integration of experiments across diverse environments identifies the genetic determinants of variation in Sorghum bicolor seed element composition

    Science.gov (United States)

    Increasing the bioavailable elemental nutrient content in the edible portions of the crop has the potential to increase the value of sorghum for human and animal nutrition. Seedling establishment and seed nutritional quality are in part determined by the sequestration of sufficient mineral nutrients...

  8. Characteristics of element composition of aerosols adsorbed on leaves by radioactivation analysis and their effects on plants

    Energy Technology Data Exchange (ETDEWEB)

    Takamatsu, Takejiro; Koshikawa, Masami [National Inst. for Environmental Studies, Tsukuba, Ibaraki (Japan); Sase, Hiroyuki; Masuzawa, Toshiyuki; Kawashima, Munetsugu; Takada, Jitsuya; Matsushita, Rokuji

    1999-01-01

    Aerosol deposits on leaves of various trees, especially cedar in different regions of Japan were collected to characterize the elemental composition using neutron activation analysis, ICP-AES, etc. and also investigate the effects of deposit aerosols on plants and the efficacy as an indicator for air pollution. Compared with the elemental composition of the soil, Se, Cr, Au, Br, As, Sb, Ag, etc. were more abundant in aerosols on cedar leaves. Especially, Sb is thought to be mostly derived from combustion of fossil fuels (exhaust gas from cars, etc.). Since Sb was accumulated on leaves at high levels and the analytical precision for Sb by neutron radioactivation was very high, the element was thought useful as an indicator for air pollution. If the amounts of Sb on the leaves of cedar and pine trees, which are widely distributed in Japan are determined, the degrees of pollution in all regions of Japan would be determined. In cedar trees of Saitama Prefecture where the deposit amounts of aerosols were comparatively larger, 42% of stoma was covered with the deposits, resulting that the rate of cuticular transpiration was increased and the amounts of basic elements leached from the leave surface was also increased. Thus, it was suggested that these changes might be the cause of recent declining of cedars in Japanese urban regions. (M.N.)

  9. Composite UHPC-AAC/CLC facade elements with modified interior plaster for new buildings and refurbishment. Materials and production technology

    Directory of Open Access Journals (Sweden)

    Lorenzo Miccoli

    2015-06-01

    Full Text Available The awareness of the environmental impact of the building sector is increasing. Steel reinforced concrete is the most commonly used construction material, though with a high-embodied energy and carbon footprint. Large environmental gains may arise if an alternative to steel reinforced concrete is developed. In this context, ultra-high performance concrete (UHPC materials are shown to be promising alternatives with advantages such as lower embodied energy and reduced environmental impact. Predictions suggest that UHPC composite elements for building envelopes could have other benefits such as an increased service life, optimised use of building area due to thinner elements and minimised maintenance due to the absence of reinforcement or use of non-corrosive reinforcing materials such as carbon fibres. In the framework of the H-HOUSE project funded by the European Commission, composite elements are developed. The aim is to create facade panels combining an autoclaved aerated concrete or cellular lightweight concrete insulation layer with an external UHPC supporting layer. To enhance occupant comfort and health, hygroscopic materials that are capable to buffer indoor air humidity shall be applied to the inside of such elements. Indoor air humidity levels are expected to be more stable, which shall subsequently improve the indoor climate and minimise potential decay to the construction.  

  10. Training affects muscle phospholipid fatty acid composition in humans

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff; Wu, B J; Willer, Mette

    2001-01-01

    Training improves insulin sensitivity, which in turn may affect performance by modulation of fuel availability. Insulin action, in turn, has been linked to specific patterns of muscle structural lipids in skeletal muscle. This study investigated whether regular exercise training exerts an effect...... on the muscle membrane phospholipid fatty acid composition in humans. Seven male subjects performed endurance training of the knee extensors of one leg for 4 wk. The other leg served as a control. Before, after 4 days, and after 4 wk, muscle biopsies were obtained from the vastus lateralis. After 4 wk......, the phospholipid fatty acid contents of oleic acid 18:1(n-9) and docosahexaenoic acid 22:6(n-3) were significantly higher in the trained (10.9 +/- 0.5% and 3.2 +/- 0.4% of total fatty acids, respectively) than the untrained leg (8.8 +/- 0.5% and 2.6 +/- 0.4%, P

  11. Temporal changes in elemental composition in decomposing filamentous algae (Cladophora glomerata and Pilayella littoralis) determined with PIXE and PIGE.

    Science.gov (United States)

    Lill, J-O; Salovius-Laurén, S; Harju, L; Rajander, J; Saarela, K-E; Lindroos, A; Heselius, S-J

    2012-01-01

    Particle-induced X-ray emission and particle-induced gamma-ray emission spectrometry were successfully applied in a study of the elemental composition of decomposing filamentous algae. Fresh brown (Pilayella littoralis) and green (Cladophora glomerata) algal materials were placed in cages at 4m depth in a water column of 8m in the Archipelago Sea, northern Baltic Sea. Every second week decaying algae were sampled from the cages to allow measurements of changes in the elemental compositions. In the study of the elemental losses the concentrations were compensated for the mass reduction. The results show that sulphur, chlorine and partly potassium were lost during decomposition of P. littoralis and C. glomerata. Most of the other elements studied were recovered in the remaining algal mass. Special attention was paid to sorption and desorption of elements, including metal binding capacity, in the decaying algal materials. The affinity order of different cations to the two algal species was established by calculation of conditional distribution coefficients, D'(M). For instance for P. littoralis the following series of binding strength (affinity) of cations were obtained: Al>Ti>Fe > Mn>Ni, Cu>Ba, Cr, Zn>Rb>K, Sr>Pb>Ca>Na>Mg. Notably is that the binding strength of strontium was more than 10 times higher for P. littoralis than for C. glomerata. Due to their high binding capacity and good affinity and selectivity for heavy metal ions these algae have great potential as biological sorbents. Large variations in elemental content during decomposition complicate the use of algae for environmental monitoring.

  12. Application of the finite-element method to improve the quasi-exact reinforcement theory of fibrous polymeric composites

    Science.gov (United States)

    Klasztorny, M.; Urbanski, A.

    2005-01-01

    In the paper, the WL quasi-exact reinforcement theory of fibrous polymeric composites is improved. An optimum compatibility condition related to the transverse shear problem for a unit cell, which brings solutions closest to reality, is derived. This condition is formulated in the form of a linear combination of maximum radial and circumferential displacements. Optimum coefficients of this combination are determined by comparing analytical and numerical solutions for a test specimen in the form of a rectangular thin plate, which is in a plane strain state and is subject to selected loading schemes. The analytic solutions are obtained for a homogenized material by using the WL reinforcement theory. The numerical solutions are found for an actual heterogeneous composite material by using the finite-element method, and they verify the WL reinforcement theory, in particular, the admissibility of Hill's assumption. An analysis performed for two composite materials shows that the improved WL reinforcement theory gives adequate displacement fields.

  13. Elemental Composition Analysis to Investigate NOx Effects on Secondary Organic Aerosol from α-Pinene Using Ultrahigh Resolution Mass Spectrometry

    Science.gov (United States)

    Lim, H. J.; Park, J. H.; Babar, Z.

    2015-12-01

    Secondary organic aerosol (SOA) accounts for 20-70% of atmospheric fine aerosol. NOx plays crucial roles in SOA formation and consequently affects the composition and yield of SOA. SOA component speciation is incomplete due to its complex composition of polar oxygenated and multifunctional species. In this study, ultrahigh resolution mass spectrometry (UHR MS) was applied to improve the understanding of NOx effects on biogenic SOA formation by identifying the elemental composition of SOA. Additional research aim was to investigate oligomer components that are considered as a driving force for SOA formation and growth. In this study α-pinene SOA from photochemical reaction was examined. SOA formation was performed in the absence and presence of NOx at dry condition (government (MEST) (No. 2011-01350000).

  14. Immune and Inflammatory Cell Composition of Human Lung Cancer Stroma.

    Directory of Open Access Journals (Sweden)

    G-Andre Banat

    Full Text Available Recent studies indicate that the abnormal microenvironment of tumors may play a critical role in carcinogenesis, including lung cancer. We comprehensively assessed the number of stromal cells, especially immune/inflammatory cells, in lung cancer and evaluated their infiltration in cancers of different stages, types and metastatic characteristics potential. Immunohistochemical analysis of lung cancer tissue arrays containing normal and lung cancer sections was performed. This analysis was combined with cyto-/histomorphological assessment and quantification of cells to classify/subclassify tumors accurately and to perform a high throughput analysis of stromal cell composition in different types of lung cancer. In human lung cancer sections we observed a significant elevation/infiltration of total-T lymphocytes (CD3+, cytotoxic-T cells (CD8+, T-helper cells (CD4+, B cells (CD20+, macrophages (CD68+, mast cells (CD117+, mononuclear cells (CD11c+, plasma cells, activated-T cells (MUM1+, B cells, myeloid cells (PD1+ and neutrophilic granulocytes (myeloperoxidase+ compared with healthy donor specimens. We observed all of these immune cell markers in different types of lung cancers including squamous cell carcinoma, adenocarcinoma, adenosquamous cell carcinoma, small cell carcinoma, papillary adenocarcinoma, metastatic adenocarcinoma, and bronchioloalveolar carcinoma. The numbers of all tumor-associated immune cells (except MUM1+ cells in stage III cancer specimens was significantly greater than those in stage I samples. We observed substantial stage-dependent immune cell infiltration in human lung tumors suggesting that the tumor microenvironment plays a critical role during lung carcinogenesis. Strategies for therapeutic interference with lung cancer microenvironment should consider the complexity of its immune cell composition.

  15. Encrustation and trace element composition of Neogloboquadrina dutertrei assessed from single chamber analyses, implications for paleotemperature estimates

    Directory of Open Access Journals (Sweden)

    G.-J. A. Brummer

    2012-08-01

    Full Text Available Crust formation is a common phenomenon in planktonic foraminifera. Because of their different formation mechanism and hence composition, crusts affect the overall test composition and therefore complicate the use of crust-bearing foraminifera in paleoceanography. Such species are often used to estimate subsurface paleotemperatures and although the influence of the crust on the trace element/Ca ratio is recognised, it has not been systematically explored between and within tests. Here we use laser ablation ICP-MS to assess the variability in trace element composition of the crust of Neogloboquadrina dutertrei within individual chambers, as well as the effect of compositional heterogeneity of the crust on whole test chemistry. Compositionally, the outer crust differs from inner layer by lower Mg/Ca and Mn/Ca, but is indistinguishable in Sr/Ca. Crust thickness decreases towards the younger chambers and it may be entirely absent from the last chamber. In contrast to Mn/Ca and Sr/Ca, crustal Mg/Ca ratios show a tendency towards higher values on the younger chambers. These patterns in crust thickness and in crust Mg/Ca indicates that temperature is not the dominant factor controlling crust composition. Temperature estimates based on N. dutertrei, and presumably other crust-forming species too, are therefore biased towards too low values. Through comparison of modern and glacial tests we show that this bias is not constant and that changes in the crust thickness and/or in the Mg/Ca values can spuriously suggest temperature changes.

  16. X-RAY BASED MICROMECHANICAL FINITE ELEMENT MODELING OF COMPOSITE MATERIALS

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard; Emerson, Monica Jane; Jespersen, Kristine Munk;

    2016-01-01

    This is a study of a uni-directional non-crimp fabric reinforced epoxy composite material typically used as the load carrying laminate in wind turbine blades. Based on a 3D xray tomography scan, the bundle and fibre/matrix structure of the composite is segmented. This segmentation is used...

  17. Temporal changes in elemental composition in decomposing filamentous algae (Cladophora glomerata and Pilayella littoralis) determined with PIXE and PIGE

    Energy Technology Data Exchange (ETDEWEB)

    Lill, J.-O., E-mail: jlill@abo.fi [Accelerator Laboratory, Turku PET Centre, Abo Akademi University, Porthansg. 3, FI-20500 Turku (Finland); Department of Natural Sciences, Abo Akademi University, Porthansg. 3, FI-20500 Turku (Finland); Salovius-Lauren, S. [Department of Biosciences, Abo Akademi University, Artillerig. 6, FI-20520 Turku (Finland); Harju, L. [Department of Chemical Engineering, Abo Akademi University, Biskopsg. 8, FI-20500 Turku (Finland); Rajander, J. [Accelerator Laboratory, Turku PET Centre, Abo Akademi University, Porthansg. 3, FI-20500 Turku (Finland); Department of Chemical Engineering, Abo Akademi University, Biskopsg. 8, FI-20500 Turku (Finland); Saarela, K.-E. [Department of Chemical Engineering, Abo Akademi University, Biskopsg. 8, FI-20500 Turku (Finland); Lindroos, A. [Department of Natural Sciences, Abo Akademi University, Porthansg. 3, FI-20500 Turku (Finland); Heselius, S.-J. [Accelerator Laboratory, Turku PET Centre, Abo Akademi University, Porthansg. 3, FI-20500 Turku (Finland)

    2012-01-01

    Particle-induced X-ray emission and particle-induced gamma-ray emission spectrometry were successfully applied in a study of the elemental composition of decomposing filamentous algae. Fresh brown (Pilayella littoralis) and green (Cladophora glomerata) algal materials were placed in cages at 4 m depth in a water column of 8 m in the Archipelago Sea, northern Baltic Sea. Every second week decaying algae were sampled from the cages to allow measurements of changes in the elemental compositions. In the study of the elemental losses the concentrations were compensated for the mass reduction. The results show that sulphur, chlorine and partly potassium were lost during decomposition of P. littoralis and C. glomerata. Most of the other elements studied were recovered in the remaining algal mass. Special attention was paid to sorption and desorption of elements, including metal binding capacity, in the decaying algal materials. The affinity order of different cations to the two algal species was established by calculation of conditional distribution coefficients, D Prime {sub M}. For instance for P. littoralis the following series of binding strength (affinity) of cations were obtained: Al > Ti > Fe Much-Greater-Than Mn > Ni, Cu > Ba, Cr, Zn Much-Greater-Than Rb > K, Sr > Pb Much-Greater-Than Ca Much-Greater-Than Na > Mg. Notably is that the binding strength of strontium was more than 10 times higher for P. littoralis than for C. glomerata. Due to their high binding capacity and good affinity and selectivity for heavy metal ions these algae have great potential as biological sorbents. Large variations in elemental content during decomposition complicate the use of algae for environmental monitoring. - Highlights: Black-Right-Pointing-Pointer Elemental concentrations in P. littoralis and C. glomerata from the Archipelago Sea in Finland were measured during decomposition. Black-Right-Pointing-Pointer PIXE and PIGE were successfully used for chemical analysis of 24 elements

  18. Enrichment analysis of Alu elements with different spatial chromatin proximity in the human genome.

    Science.gov (United States)

    Gu, Zhuoya; Jin, Ke; Crabbe, M James C; Zhang, Yang; Liu, Xiaolin; Huang, Yanyan; Hua, Mengyi; Nan, Peng; Zhang, Zhaolei; Zhong, Yang

    2016-04-01

    Transposable elements (TEs) have no longer been totally considered as "junk DNA" for quite a time since the continual discoveries of their multifunctional roles in eukaryote genomes. As one of the most important and abundant TEs that still active in human genome, Alu, a SINE family, has demonstrated its indispensable regulatory functions at sequence level, but its spatial roles are still unclear. Technologies based on 3C (chromosome conformation capture) have revealed the mysterious three-dimensional structure of chromatin, and make it possible to study the distal chromatin interaction in the genome. To find the role TE playing in distal regulation in human genome, we compiled the new released Hi-C data, TE annotation, histone marker annotations, and the genome-wide methylation data to operate correlation analysis, and found that the density of Alu elements showed a strong positive correlation with the level of chromatin interactions (hESC: r = 0.9, P elements like enhancers and promoters (Enhancer: hESC: r = 0.997, P = 2.3 × 10(-4); IMR90: r = 0.934, P = 2 × 10(-2); Promoter: hESC: r = 0.995, P = 3.8 × 10(-4); IMR90: r = 0.996, P = 3.2 × 10(-4)). Further investigation involving GC content and methylation status showed the GC content of Alu covered sequences shared a similar pattern with that of the overall sequence, suggesting that Alu elements also function as the GC nucleotide and CpG site provider. In all, our results suggest that the Alu elements may act as an alternative parameter to evaluate the Hi-C data, which is confirmed by the correlation analysis of Alu elements and histone markers. Moreover, the GC-rich Alu sequence can bring high GC content and methylation flexibility to the regions with more distal chromatin contact, regulating the transcription of tissue-specific genes.

  19. Sources of aerosol as determined from elemental composition and size distributions in Beijing

    Science.gov (United States)

    Zhang, Wenjie; Zhuang, Guoshun; Guo, Jinghua; Xu, Dongqun; Wang, Wei; Baumgardner, Darrel; Wu, Zhiyuan; Yang, Wen

    2010-02-01

    Samples of PM 2.5, PM 10, and TSP from 2001 to 2003 have been collected in Beijing during spring (low-dust), spring (high dust), summer and winter. The concentration of TSP, PM 10, and PM 2.5 was most abundant in spring with high dust followed by winter, spring with little dust and summer. The average mass ratios of PM > 10 , PM 2.5-10 and PM 2.5 to TSP show that the large coarse fraction (PM > 10 ) and the fine fraction (PM 2.5) contribute most in spring with high dust while PM 2.5, PM 2.5-10, and PM > 10 contributed similar fractions to TSP in summer and PM 2.5 in winter. Sixteen cascade impaction samples were collected for elemental analysis in 2000 and 2001 and 16 major components were analyzed by PIXE. Based on the characteristics of the size distribution, three different patterns are observed: coarse mode, fine mode and bimodal mode. Different groups showed different characteristics. Crustal elements showed stable size shapes between different seasons, however, pollution elements showed complex and more variations, and the size distribution showed tendency to vary between unimodal fine modes and bimodal modes. Additionally, the concentration of aerosols and the temporal variation of the elements varied significantly according to different meteorological conditions especially on haze-fog weather conditions. Different elements showed different size distributions on haze-fog weather, i.e. crustal elements of Al, Si, Ca showed similar variation with those average days, pollution elements of S, As, Zn showed significantly higher level than those average values but mixed elements of K, Mn, Cu, Pb showed not so higher than those pollution elements. The high S in haze-fog weather was most from water soluble sulfate parts, the bimodal modes of elements showed unimodal variation and the peak of accumulation modes showed tendency variation to the larger sizes in haze-fog weather. However, most crustal elements showed not much increase during haze-fog condition, which is

  20. Elemental composition and mineralogical characteristics of coastal marine sediments of Tutuila, American Samoa.

    Science.gov (United States)

    Morrison, R J; Peshut, P J; Lasorsa, Brenda K

    2010-06-01

    Surface sediment samples were collected from 5 pristine coastal areas and 1 potentially contaminated coastal site on Tutuila, the main island of American Samoa, an isolated island group in the South Pacific Ocean. Samples were analysed for total element analysis (15 elements) and mineralogy. The results indicated no evidence of trace element contamination at any site, including Pago Pago Harbour. Inter-site variations could be explained assuming the sediments consisted predominantly of coralline sand and rubble with varying quantities of basaltic materials derived from local catchments.

  1. Can experimental data in humans verify the finite element-based bone remodeling algorithm?

    DEFF Research Database (Denmark)

    Wong, C.; Gehrchen, P.M.; Kiaer, T.

    2008-01-01

    STUDY DESIGN: A finite element analysis-based bone remodeling study in human was conducted in the lumbar spine operated on with pedicle screws. Bone remodeling results were compared to prospective experimental bone mineral content data of patients operated on with pedicle screws. OBJECTIVE......: The validity of 2 bone remodeling algorithms was evaluated by comparing against prospective bone mineral content measurements. Also, the potential stress shielding effect was examined using the 2 bone remodeling algorithms and the experimental bone mineral data. SUMMARY OF BACKGROUND DATA: In previous studies......, in the human spine, the bone remodeling algorithms have neither been evaluated experimentally nor been examined by comparing to unsystematic experimental data. METHODS: The site-specific and nonsite-specific iterative bone remodeling algorithms were applied to a finite element model of the lumbar spine...

  2. The Establishment and Development of Finite Element Model of Human Cervical Vertebra and Its Application Example

    Institute of Scientific and Technical Information of China (English)

    SHEN Xiao-wen; YU Hang-ping; ZOU Wei

    2008-01-01

    .The incidence rate of cervical spondylosis is high,and due to the complicacy of cervical vertebra structure, irregularity of shapes and non-uniformity of components, sometimes it's difficult to achieve planned objectives by experiments in vitro through stress and strain analysis. Besides, the biomechanical factors are of vital significance in the cause of spinal disorders. In this paper the author makes a summary of the present modeling of human cervical vertebra and describes the major methods of establishing the finite element model of human cervical vertebra through several self-constructed models. With the advance of computer technology, the finite element methods have been rapidly developed in cervical vertebra biomechanical researches and have became a major approach for biomechanical researches to simulate more and more clinical conditions.

  3. Investigation of elemental distribution in human femoral head by PIXE and SRXRF microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.X. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)]. E-mail: yxzhang@sinap.ac.cn; Wang, Y.S. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)]. E-mail: wangyinsong@sinap.ac.cn; Zhang, Y.P. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)]. E-mail: zhangyongping@sinap.ac.cn; Zhang, G.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)]. E-mail: zhangguilin@sinap.ac.cn; Huang, Y.Y. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: huangyy@mail.ihep.ac.cn; He, W. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: hew@mail.ihep.ac.cn

    2007-07-15

    In order to study the distribution and possible degenerative processes inducing the loss of inorganic substances in bone and to provide a scientific basis for the prevention and therapy of osteoporosis, proton induced X-ray emission (PIXE) method is used for the determination of elemental concentrations in femoral heads from five autopsies and seven patients with femoral neck fractures. Synchrotron radiation X-ray fluorescence (SRXRF) microprobe analysis technique is used to scan a slice of the femoral head from its periphery to its center, via cartilage, compact and spongy zones. The specimen preparation and experiment procedure are described in detail. The results show that the concentrations of P, Ca, Fe, Cu, Sr in the control group are higher than those in the patient group, but the concentrations of S, K, Zn, Mn are not significantly different. The quantitative results of elemental distribution, such as Ca, P, K, Fe, Zn, Sr and Pb in bone slice tissue including cartilage, substantial compact and substantial spongy, are investigated. The data obtained show that the concentrations of Ca, P, K, (the major elements of bone composition), are obviously low in both spongy and cartilage zones in the patient group, but there are no remarkable differences in the compact zone. Combined with the correlations between P, K, Zn, Sr and Ca, the loss mechanism of minerals and the physiological functions of some metal elements in bone are also discussed.

  4. [THE LEGAL STATUS OF ELEMENTS AND PRODUCTS OF THE HUMAN BODY: OBJECT OR SUBJECT OF LAW?].

    Science.gov (United States)

    De Lameigné, Anaïs Gayte-Papon

    2015-07-01

    The 2004 Act on bioethics has amended the 1994 Act regarding the donation and the use of elements and products of the human body, medically assisted procreation and prenatal diagnosis. The very purpose of these laws led the legislature not to attempt the summa divisio order distinguishing the object to the person. The analysis of bioethical laws reveals the consecration of the non-commercialization of the human body at the expense of its unavailability. Bioethical laws appear to be catalysts of biological scientific advances releasing the status of the components and the products of the human body while framing it. By limiting scientific opportunities, they prevent human beings from trying to play the sorcerer's apprentice.

  5. Major factors influencing the elemental composition of surface estuarine sediments: the case of 15 estuaries in Portugal.

    Science.gov (United States)

    Mil-Homens, M; Vale, C; Raimundo, J; Pereira, P; Brito, P; Caetano, M

    2014-07-15

    Upper sediments (0-5 cm) were sampled in 94 sites of water bodies of the fifteen Portuguese estuaries characterized by distinct settings of climate, topography and lithology, and marked by diverse anthropogenic pressures. Confined areas recognized as highly anthropogenic impacted, as well as areas dominated by erosion or frequently dredged were not sampled. Grain size, organic carbon (Corg), Al and trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were determined. Normalisation of trace element concentrations to Al and Corg, correlations between elements and Principal Component Analysis (PCA) allowed identifying elemental associations and the relevance of grain-size, lithology and anthropogenic inputs on sediment chemical composition. Whereas grain-size is the dominant effect for the majority of the studied estuaries, the southern estuaries Mira, Arade and Guadiana are dominated by specific lithologies of their river basins, and anthropogenic effects are identified in Ave, Leça, Tagus and Sado. This study emphasizes how baseline values of trace elements in sediments may vary within and among estuarine systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    OpenAIRE

    Andreas Bitter; Nüssler, Andreas K.; Thasler, Wolfgang E.; Kathrin Klein; Zanger, Ulrich M.; Matthias Schwab; Oliver Burk

    2015-01-01

    Background/Aims: Sterol regulatory element-binding protein (SREBP) 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human li...

  7. Human health risk assessment of potentially toxic elements (PTEs) from environmental matrices

    OpenAIRE

    Elom, Nwabueze

    2012-01-01

    In assessing human health risk of potentially toxic elements (PTEs), it is not the concentration of PTEs in the environmental matrices that is of greatest concern but the fraction that is absorbed into the body via the exposure pathways. The determination of this fraction (i.e. the bioaccessible fraction) through the application of bioaccessibility protocols is the focus of this work. The study investigated human health risk of PTEs (As, Cd, Cr, Cu, Pb, Mn, Ni and Zn) from oral ingestion of s...

  8. Vegetation evolution on the central Chinese Loess Plateau since late Quaternary evidenced by elemental carbon isotopic composition

    Institute of Scientific and Technical Information of China (English)

    ZHOU Bin; SHEN ChengDe; ZHENG HongBo; ZHAO MeiXun; SUN YanMin

    2009-01-01

    There are many controversial issues in loess studies such as natural vegetation types on the Chinese Loess Plateau during the historical periods and the spatial and temporal evolution of C3/C4 plants.Elemental carbon isotopic composition (δ13Cec) in the loess section may offer new evidence for these problems. Elemental carbon (EC) is produced by incomplete combustion of vegetation, and its carbon isotopic composition has a very small difference from that of the formal vegetation, then δ13Cec can be used as a record to recover the changes of vegetation. Elemental carbon was extracted by applying the oxidation method from the loess-paleosol sequence in the central Chinese Loess Plateau, and its carbon isotope composition was analyzed by the isotope mass spectrometer. The results showed that the vegetation in this region was a mixed type of C3 and C4 plants, dominated with C3 plants in most of the time. Since late Quaternary, C3/C4 plants may not follow a simple glacial-interglacial cycle mode on the Chinese Loess Plateau, but showing fluctuations. C3 plants increased gradually in L4 period, and more C3 plants occurred during S3 period, and C4 plants increased again during L3-L2 periods, after that, C3plants dominated again during S1-S0 periods. During periods of paleosol development, C3 plants were abundant in S3 and S1, and there were more C4 plants in S2 and S0. During periods of loess sedimentation, there were more C3 plants in L4 and L1, and there were more C4 plants in L3 and L2. On the orbital timescale, the vegetation variations revealed by δ13Cec record are consistent with the results of pollen data and also similar to the results obtained by organic carbon isotopic composition since the last glacial period.

  9. Inductively coupled plasma optical emission spectroscopy determination of trace element composition of argan oil.

    Science.gov (United States)

    Gonzálvez, A; Ghanjaoui, M E; El Rhazi, M; de la Guardia, M

    2010-02-01

    A methodology based on inductively coupled plasma optical emission spectroscopy (ICP-OES) after microwave assisted acid digestion has been developed to determine the trace element content of Moroccan argan oil. Limit of detection values equal or lower than few mg/kg were obtained for all elements under study. To assure the accuracy of the whole procedure, recovery studies were carried out on argan oil samples spiked at different concentration levels from 10 to 200 µg/L. Quantitative average recovery values were obtained for all elements evaluated, demonstrating the suitability of this methodology for the determination of trace elements in argan oil samples. Aluminum, calcium, chromium, iron, potassium, lithium, magnesium, sodium, vanadium and zinc were quantitatively determined in Moroccan argan oils being found that their concentration is different of that found in other edible oils thus offering a way for authentication and for the evaluation of possible adulterations.

  10. Description of selected structural elements of composite foams using statistical methods

    Directory of Open Access Journals (Sweden)

    K. Gawdzińska

    2011-04-01

    Full Text Available This article makes use of images from a computer tomograph for the description of selected structure elements of metal and compositefoams by means of statistical methods. Besides, compression stress of the tested materials has been determined.

  11. What Do We Know About Elemental Bulk Chondrule Compositions? Presenting the ChondriteDB Database

    Science.gov (United States)

    Hezel, D. C.; Harak, M.; Libourel, G.

    2016-08-01

    We compiled an elemental chondrule and matrix database for Big Data analyses (>3500 entires in 107 categories). We use this first overview of the entire chondrule population for comparisons and conclusions on chondrule formation conditions.

  12. Trace Element Composition of Metal and Sulphides in Iron Meteorites Determined Using ICP-MS

    Science.gov (United States)

    Giscard, M. D.; Hammond, S. J.; Bland, P. A.; Benedix, G. K.; Rogers, N. W.; Russell, S. S.; Genge, M. J.; Rehkamper, M.

    2012-09-01

    We measured trace element concentrations in Nantan, Toluca, Cape York, Carthage, Gibeon and Dronino. Poikiloblastic daubreelite in Gibeon indicates shock metamorphism. There is a volatile depletion in metal and sulphides.

  13. Preliminary Results on Magnetic Mineralogy and Elemental Composition of Meteorites from Geological Museum of Kazan University

    Science.gov (United States)

    Kuzina, D. M.; Nurgaliev, D. K.; Gareev, B. I.; Batalin, G. A.; Silantev, V. V.

    2016-08-01

    Thermomagnetic analysis (magnetic mineralogy) and Micro X-ray Fluorescence analysis (mapping) were made for collection of meteorites. As a result we have elements distribution on surface of meteorites and Fe-Ni presence in meteorites.

  14. Principles of Linguistic Composition Below and Beyond the Clause—Elements of a semantic combinatorial system

    DEFF Research Database (Denmark)

    Bundgaard, Peer

    2006-01-01

    The present investigation challenges the traditional distinction between cohesion and coherence; i.e., the distinction between the syntactical rules governing the composition of lexical units within the scope of the clause and the semantic-pragmatic rules guiding the composition of text units...... beyond the scope of the clause. To this end it exposes two major principles of semantic combination that are active through all levels of linguistic composition: viz. frame-schematic structure and narrative structure. These principles are considered as being components of a semantic combinatorial system...

  15. Measurements of elemental composition in background aerosol on the west coast of Sweden

    Science.gov (United States)

    Öblad, M.; Selin, E.

    Concentrations of 14 elements in long distance transported aerosol have been measured in a rural site on the W coast of Sweden. The measurements were made during one winter and two summer periods, 1981-1984. Sampling was made with a dichotomous virtual impactor. Element analysis was made by photon induced X-ray fluorescence. The element concentrations were related to air mass trajectories. A strong dependence of the concentration variations with air mass history is found for most elements, in particular Pb, S, V, Zn and Cl. Median concentrations for the 14 elements in the two size fractions are reported and compared with previous measurements in central Sweden at the same latitude. Significant deviations are found for S and V. Concentrations of particulate S have proven to be very insensitive to locally produced SO 2 emissions. This makes measurements of fine particulate S on the Swedish W coast an excellent tool for checking the S transport from other countries to Sweden. The ratios Br/Pb in fine particles and the coarse/fine ratios for particulate lead have, together with air mass trajectories, been used to suggest source areas for automotive lead. The soil derived elements, Fe, Ca, Ti and Mn, also demonstrate variations with air mass trajectories. Enrichment factors for coarse particles of Ca, Mn and Ti with iron as a reference show variations that we believe are typical for the soil of the source area.

  16. Elemental composition of green coffee and its contribution to dietary intake.

    Science.gov (United States)

    Şemen, Sevcan; Mercan, Selda; Yayla, Murat; Açıkkol, Münevver

    2017-01-15

    The concentration of twenty-seven elements (Li, Be, B, Mg, Al, P, K, Ca, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Sn, Sb, Ba, Hg, Pb, Bi, Th, and U) in green coffee samples and their infusions were determined by using inductively coupled plasma-mass spectrometry (ICP-MS). Prior to analysis, green coffee samples were prepared by microwave digestion, while infusions were analyzed without any pre-treatment. The accuracy and precision of the proposed methods were verified by recovery experiments. Considering samples; K, Cu, and Al had the highest mean concentrations with 6714.5μgg(-1), 12.1μgg(-1), and 25.9μgg(-1) among major, trace and toxic elements, respectively. The impact of brewing type on leachability of elements was also studied and the results outlined that mean leachability of elements to Turkish coffee were greater than to mud coffee. Furthermore, dietary element intakes through green coffee consumption were also estimated. This is the first study presenting wide range of elements in green coffee brews and calculating dietary intakes.

  17. Bulk compositions of metallic Fe-Ni of chondrites: Constraints on fractionation of siderophile and chalcophile elements

    Institute of Scientific and Technical Information of China (English)

    XU Lin; LIN Yangting; WANG Shijie; OUYANG Ziyuan

    2009-01-01

    Bulk compositions of metallic Fe-Ni from two equilibrated ordinary chondrites, Jilin (H5) and Anlong (H5), and two unequilibrated ones, GRV 9919 (L3) and GRV 021603 (H3), were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The CI-, Co-normalized abundances of siderophile and chalcophile elements of metallic Fe-Ni from the unequilibrated ordinary chondrites correlate with 50% condensation temperatures (i.e., volatility) of the elements. The refractory siderophile elements (i.e., platinum group elements, Re), Au, Ni and Co show a flat pattern (1.01(CI Co-normalized), while moderate elements (As, Cu, Ag, Ga, Ge, Zn) decrease with volatility from 0.63(CI (Co-normalized, As) to 0.05(CI (Co-normalized, Zn). Cr and Mn show deficit relative to the trend, probably due to their main partition in silicates and sulfides (nonmagnetic). Metallic Fe-Ni from the equilibrated ordinary chondrites shows similar patterns, except for strong deficit of Cr, Mn, Ag and Zn. It is indicated that these elements were almost all partitioned into silicates and/or sulfides during thermal metamorphism. The similar deficit of Cr, Mn, Ag and Zn was also found in iron meteorites.Our analyses demonstrate similar behaviors of W and Mo as refractory siderophile elements during condensation of the solar nebula, except for slight depletion of Mo in the L3 and H5 chondrites. The Mo-depletion of metallic Fe-Ni from GRV 9919 (L3) relative to GRV 021603 (H3) could be due to a more oxidizing condition of the former than the latter in the solar nebula. In contrast, the Mo-depletion of the metallic Fe-Ni from the H5 chondrites may reflect partition of Mo from metal to silicates and/or sulfides during thermal metamorphism in the asteroidal body.

  18. New Approach for Near-Real-Time Measurement of Elemental Composition of Aerosol Using Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Diwakar, Prasoon; Kulkarni, Pramod; Birch, M. Eileen

    2015-01-01

    A new approach has been developed for making near-real-time measurement of elemental composition of aerosols using plasma spectroscopy. The method allows preconcentration of miniscule particle mass (pg to ng) directly from the sampled aerosol stream through electrostatic deposition of charged particles (30–900 nm) onto a flat-tip microneedle electrode. The collected material is subsequently ablated from the electrode and monitored by laser-induced breakdown spectroscopy. Atomic emission spectra were collected using a broadband spectrometer with a wavelength range of 200–980 nm. A single-sensor delay time of 1.3 μs was used in the spectrometer for all elements to allow simultaneous measurement of multiple elements. The system was calibrated for various elements including Cd, Cr, Cu, Mn, Na, and Ti. The absolute mass detection limits for these elements were experimentally determined and found to be in the range of 0.018–5 ng. The electrostatic collection technique has many advantages over other substrate-based methods involving aerosol collection on a filter or its focused deposition using an aerodynamic lens. Because the particle mass is collected over a very small area that is smaller than the spatial extent of the laser-induced plasma, the entire mass is available for analysis. This considerably improves reliability of the calibration and enhances measurement accuracy and precision. Further, the aerosol collection technique involves very low pressure drop, thereby allowing higher sample flow rates with much smaller pumps—a desirable feature for portable instrumentation. Higher flow rates also make it feasible to measure trace element concentrations at part per trillion levels. Detection limits in the range of 18–670 ng m−3 can be achieved for most of the elements studied at a flow rate of 1.5 L min−1 with sampling times of 5 min. PMID:26692632

  19. New Approach for Near-Real-Time Measurement of Elemental Composition of Aerosol Using Laser-Induced Breakdown Spectroscopy.

    Science.gov (United States)

    Diwakar, Prasoon; Kulkarni, Pramod; Birch, M Eileen

    A new approach has been developed for making near-real-time measurement of elemental composition of aerosols using plasma spectroscopy. The method allows preconcentration of miniscule particle mass (pg to ng) directly from the sampled aerosol stream through electrostatic deposition of charged particles (30-900 nm) onto a flat-tip microneedle electrode. The collected material is subsequently ablated from the electrode and monitored by laser-induced breakdown spectroscopy. Atomic emission spectra were collected using a broadband spectrometer with a wavelength range of 200-980 nm. A single-sensor delay time of 1.3 μs was used in the spectrometer for all elements to allow simultaneous measurement of multiple elements. The system was calibrated for various elements including Cd, Cr, Cu, Mn, Na, and Ti. The absolute mass detection limits for these elements were experimentally determined and found to be in the range of 0.018-5 ng. The electrostatic collection technique has many advantages over other substrate-based methods involving aerosol collection on a filter or its focused deposition using an aerodynamic lens. Because the particle mass is collected over a very small area that is smaller than the spatial extent of the laser-induced plasma, the entire mass is available for analysis. This considerably improves reliability of the calibration and enhances measurement accuracy and precision. Further, the aerosol collection technique involves very low pressure drop, thereby allowing higher sample flow rates with much smaller pumps-a desirable feature for portable instrumentation. Higher flow rates also make it feasible to measure trace element concentrations at part per trillion levels. Detection limits in the range of 18-670 ng m(-3) can be achieved for most of the elements studied at a flow rate of 1.5 L min(-1) with sampling times of 5 min.

  20. Recovering the Elemental Composition of Comet Wild 2 Dust in Five Stardust Impact Tracks and Terminal Particles in Aerogel

    Energy Technology Data Exchange (ETDEWEB)

    Ishii, H A; Brennan, S; Bradley, J P; Luening, K; Ignatyev, K; Pianetta, P

    2007-01-04

    The elemental (non-volatile) composition of five Stardust impact tracks and terminal particles left from capture of Comet 81P/Wild 2 dust were mapped in a synchrotron x-ray scanning microprobe with full fluorescence spectra at each pixel. Because aerogel includes background levels of several elements of interest, we employ a novel 'dual threshold' approach to discriminate against background contaminants: an upper threshold, above which a spectrum contains cometary material plus aerogel and a lower threshold below which it contains only aerogel. The difference between normalized cometary-plus-background and background-only spectra is attributable to cometary material. The few spectra in between are discarded since misallocation is detrimental: cometary material incorrectly placed in the background spectrum is later subtracted from the cometary spectrum, doubling the loss of reportable cometary material. This approach improves precision of composition quantification. We present the refined whole impact track and terminal particle elemental abundances for the five impact tracks. One track shows mass increases in Cr and Mn (1.4x), Cu, As and K (2x), Zn (4x) and total mass (13%) by dual thresholds compared to a single threshold. Major elements Fe and Ni are not significantly affected. The additional Cr arises from cometary material containing little Fe. We exclude Au intermixed with cometary material because it is found to be a localized surface contaminant carried by comet dust into an impact track. The dual threshold technique can be used in other situations where elements of interest in a small sample embedded in a matrix are also present in the matrix itself.