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Sample records for surface elemental composition

  1. 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.

  2. Determination of planetary surfaces elemental composition by gamma and neutron spectroscopy

    International Nuclear Information System (INIS)

    Diez, B.

    2009-06-01

    Measuring the neutron and gamma ray fluxes produced by the interaction of galactic cosmic rays with planetary surfaces allow constraining the chemical composition of the upper tens of centimeters of material. Two different angles are proposed to study neutron and gamma spectroscopy: data processing and data interpretation. The present work is in line with two experiments, the Mars Odyssey Neutron Spectrometer (MONS) and the Selene Gamma Ray Spectrometer. A review of the processing operations applied to the MONS dataset is proposed. The resulting dataset is used to determine the depth of the hydrogen deposits below the Martian surface. In water depleted regions, neutron data allow constraining the concentration in elements likely to interact with neutrons. The confrontation of these results to those issued from the Gamma Ray Spectrometer onboard Mars Odyssey provides interesting insight on the geologic context of the Central Elysium Planitia region. These martian questions are followed by the study of the Selene gamma ray data. Although only preliminary processing has been done to date, qualitative lunar maps of major elements (Fe, Ca, Si, Ti, Mg, K, Th, U) have already been realized. (author)

  3. Effect of elemental composition of ion beam on the phase formation and surface strengthening of structural materials

    International Nuclear Information System (INIS)

    Avdienko, K.I.; Avdienko, A.A.; Kovalenko, I.A.

    2001-01-01

    The investigation results are reported on the influence of ion beam element composition on phase formation, wear resistance and microhardness of surface layers of titanium alloys VT-4 and VT-16 as well as stainless steel 12Kh18N10T implanted with nitrogen, oxygen and boron. It is stated that ion implantation into structural materials results in surface hardening and is directly dependent on element composition of implanted ion beam. The presence of oxygen in boron or nitrogen ion beams prevents the formation of boride and nitride phases thus decreasing a hardening effect [ru

  4. 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.

  5. Comparison of different types of phacoemulsification tips. I. Quantitative analysis of elemental composition and tip surface microroughness.

    Science.gov (United States)

    Tsaousis, Konstantinos T; Werner, Liliana; Perez, Jesus Paulo; Li, He J; Reiter, Nicholas; Guan, Jia J; Mamalis, Nick

    2016-09-01

    To evaluate the elemental composition of phacoemulsification tips and their surface roughness in the microscale. John A. Moran Eye Center and Utah Nanofab, College of Engineering, University of Utah, Salt Lake City, Utah, USA. Experimental study. Seven types of phacoemulsification tips were studied. The phaco tips were examined through energy-dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) for elemental composition. In addition, the roughness of the opening in all tips was assessed through 3-dimensional white-light interferometry. Elemental analysis showed considerable differences in the surface layers between manufacturers. Alcon tips had a thinner oxidized titanium (Ti) layer in their surface. Through XPS, vanadium was not detected in the superficial layers of any tip, but only in deeper levels. The microroughness surface analysis showed comparable results regarding their root-mean-square (RMS) metric. Maximum peak valley distance values varied and appeared to be dependent on the quality of material process rather than the material itself. Phacoemulsification tips are made of Ti alloys and showed differences between models, especially regarding their composition in the superficial layers. Their opening end roughness showed an overall appropriate RMS value of less than 1.0 μm in all cases. The existence of small defected areas highlights the importance of adequate quality control of these critical surgical instruments. None of the authors has a financial or proprietary interest in any material or method mentioned. Copyright © 2016 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  6. A study of Venus surface elemental composition from 14 MeV neutron induced gamma ray spectroscopy: Activation analysis

    International Nuclear Information System (INIS)

    Jun, I.; Kim, W.; Smith, M.; Mitrofanov, I.; Litvak, M.

    2011-01-01

    The surface elemental composition of Venus can be determined using an artificially pulsed 14 MeV neutron generator (PNG) combined with a gamma ray spectrometer (GRS). The 14 MeV neutrons will interact with the surface materials and generate gamma rays, characteristic of specific elements, whose energy spectrum will be measured by GRS. These characteristic gamma rays are produced mainly through 3 different neutron interaction mechanisms: capture, inelastic, and activation reactions. Each reaction type has a different neutron energy dependency and different time scale for gamma ray production and transport. Certain elements are more easily identified through one reaction type over the others. Thus, careful analysis of the gamma ray spectra during and after the neutron pulse provides a comprehensive understanding of the surface elemental composition. In this paper, we use a well-tested neutron/gamma transport code, called Monte Carlo N-Particles (MCNP), to investigate the measurement capability of a PNG-GRS detection system through the neutron activation reactions. An activation analysis was performed for a representative soil composition of Venus with a notional operational scenario of PNG and GRS. The analysis shows that the proposed instrument concept can identify most of the modeled surface elements at Venus with sufficient accuracy through the activation mode. Specifically, U, Th, K, Si can be measured to within 1%, Fe within 2%, Al within 10%, Ca within 5%, Mg with 15%, Mn with 20%, and Cl within 6%. Although modeled in the analysis, it is shown that the activation mode alone cannot distinguish the S and Ti peaks.

  7. Sensing element for detection of polar organic vapours on the base of polyaniline-composite - Effect of substrate surface area

    International Nuclear Information System (INIS)

    Olejnik, Robert; Babar, Dipak Gorakh; Slobodian, Petr; Matyas, Jiri

    2016-01-01

    Conductive polymer polyaniline (PANI) was synthesized by oxidative polymerization of aniline hydrochloride as a source of aniline and ammonium persulfate as an oxidation agent. The polymerization process is relatively easy and cheap. The reaction was carried out in presence of polymer substrate, in our case polyethylene terephthalate (PET) as a representative of smooth surface substrate and polyvinylidenfluoride (PVDF) nanofibers membrane as a representative of porous substrate. Both these substrates were covered by polyaniline (PANI) and used as a sensing element for organic vapors detection. The detection was made by measuring and the record of the change of resistivity during adsorption and desorption of saturated vapors. The result shows that sensitivity decreases with increasing polarity of chosen solvent in order N,N- Dimethylformamide (DMF), N,N-Dimethylacetamide (DMAc) and Dimethyl sulfoxide (DMSO). The PANI base sensing element on PVDF substrate improves sensitivity, selectivity and it also has good reversibility and repeatability. (paper)

  8. The Auger-spectroscopic study of the elemental composition of the fracture surface of titanic alloy vt-22 with different structure

    International Nuclear Information System (INIS)

    Tkachenko, E.A.; Chokin, K.Sh.; Masyagin, V.E.; Chasnikov, A.I.

    2002-01-01

    High titanium alloys belong to a group of materials with high thermal stability and strength-to-weight ratio, which, for example, are widely used in aviation. The structure and properties of this materials strongly depends on variations of their elemental composition. In the dependence on the content of alloying elements the structure after the hardening from β-phase changes that, in its turn, leads to the alteration of the mechanical properties. So, the study of the redistribution of the impurity and alloying elements at straining the alloys with different structures that associated with premature destruction of construction components made of the titanic alloys is of great interest. The present work performs the results of the Auger spectroscopic investigation of the elemental composition of the alloy VT-22 fraction surface. This investigation was fulfilled for the alloy samples with different structure: laminated (L), globular (G), and laminated-globular ones with the plasticity level 1280-1350 MPa. The alterations of the elemental concentrations on the fracture surface have been estimated with the special Auger-spectrometer (OSIPR-1). The analysis of the fracture surface for samples with L- and G-structures right after the destruction at different velocities have shown the enrichment of the surface with aluminium, oxygen, and carbon in bound state as titan carbide (TiC). At this, the content of these elements decreases with the growth of the test velocity. The impurities in the samples with different structures behave as follows. In the sample with L-structure sulphur, phosphorus, and calcium on the fracture surface have been detected. At this, with the growth of the test velocity their concentration increases, but not significantly. In the samples with G-structure sulphur presents on the surface only at great straining velocities, and phosphorus is absent. At the analysis of the obtained results, one should note that the fracture surface is being enriched

  9. 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

    2017-08-01

    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 rice samples, respectively, median PA concentrations were 5438 and 1906 mg kg -1 , and median PA:Zn molar ratios were 29 and 13. Concentrations of potentially toxic elements (mg kg -1 , dry weight) in brown and white rice samples, respectively, were: As = 0.030 and 0.006; Cd  ≤ 0.002 and 0.006; Pb = 0.008 and 0.008. Approximately 95 % of As was found to be inorganic As, where this could be quantified. Malawian rice, like the more widely consumed staple grain maize, contains inadequate Ca, I, Se or Zn to meet dietary requirements. Biofortification strategies could significantly increase Se and Zn concentrations and require further investigation. Concentrations of Fe in rice grain varied

  10. Differences in the Activities of Eight Enzymes from Ten Soil Fungi and Their Possible Influences on the Surface Structure, Functional Groups, and Element Composition of Soil Colloids

    Science.gov (United States)

    Wang, Wenjie; Li, Yanhong; Wang, Huimei; Zu, Yuangang

    2014-01-01

    How soil fungi function in soil carbon and nutrient cycling is not well understood by using fungal enzymatic differences and their interactions with soil colloids. Eight extracellular enzymes, EEAs (chitinase, carboxymethyl cellulase, β-glucosidase, protease, acid phosphatase, polyphenol oxidase, laccase, and guaiacol oxidase) secreted by ten fungi were compared, and then the fungi that showed low and high enzymatic activity were co-cultured with soil colloids for the purpose of finding fungi-soil interactions. Some fungi (Gomphidius rutilus, Russula integra, Pholiota adiposa, and Geastrum mammosum) secreted 3–4 enzymes with weak activities, while others (Cyathus striatus, Suillus granulate, Phallus impudicus, Collybia dryophila, Agaricus sylvicola, and Lactarius deliciosus) could secret over 5 enzymes with high activities. The differences in these fungi contributed to the alterations of functional groups (stretching bands of O-H, N-H, C-H, C = O, COO- decreased by 11–60%, while P = O, C-O stretching, O-H bending and Si-O-Si stretching increased 9–22%), surface appearance (disappearance of adhesive organic materials), and elemental compositions (11–49% decreases in C1s) in soil colloids. Moreover, more evident changes were generally in high enzymatic fungi (C. striatus) compared with low enzymatic fungi (G. rutilus). Our findings indicate that inter-fungi differences in EEA types and activities might be responsible for physical and chemical changes in soil colloids (the most active component of soil matrix), highlighting the important roles of soil fungi in soil nutrient cycling and functional maintenance. PMID:25398013

  11. Differences in the activities of eight enzymes from ten soil fungi and their possible influences on the surface structure, functional groups, and element composition of soil colloids.

    Science.gov (United States)

    Wang, Wenjie; Li, Yanhong; Wang, Huimei; Zu, Yuangang

    2014-01-01

    How soil fungi function in soil carbon and nutrient cycling is not well understood by using fungal enzymatic differences and their interactions with soil colloids. Eight extracellular enzymes, EEAs (chitinase, carboxymethyl cellulase, β-glucosidase, protease, acid phosphatase, polyphenol oxidase, laccase, and guaiacol oxidase) secreted by ten fungi were compared, and then the fungi that showed low and high enzymatic activity were co-cultured with soil colloids for the purpose of finding fungi-soil interactions. Some fungi (Gomphidius rutilus, Russula integra, Pholiota adiposa, and Geastrum mammosum) secreted 3-4 enzymes with weak activities, while others (Cyathus striatus, Suillus granulate, Phallus impudicus, Collybia dryophila, Agaricus sylvicola, and Lactarius deliciosus) could secret over 5 enzymes with high activities. The differences in these fungi contributed to the alterations of functional groups (stretching bands of O-H, N-H, C-H, C = O, COO- decreased by 11-60%, while P = O, C-O stretching, O-H bending and Si-O-Si stretching increased 9-22%), surface appearance (disappearance of adhesive organic materials), and elemental compositions (11-49% decreases in C1s) in soil colloids. Moreover, more evident changes were generally in high enzymatic fungi (C. striatus) compared with low enzymatic fungi (G. rutilus). Our findings indicate that inter-fungi differences in EEA types and activities might be responsible for physical and chemical changes in soil colloids (the most active component of soil matrix), highlighting the important roles of soil fungi in soil nutrient cycling and functional maintenance.

  12. Elemental composition of cosmic ray

    International Nuclear Information System (INIS)

    Yanagida, Shohei

    1987-01-01

    The report first summarizes some data that have been obtained so far from observation of isotopes and elements in cosmic rays in the low energy region. Then, objectives of studies planned to be carried out with Astromag are outlined and the number of incident particles expected to be measured by baloon observation is estimated. Heavy elements with atomic numbers of greater than 30 are considered to be formed through neutron absorption reactions by the s- or r-process. Observations show that products of the r-process is abundant in cosmic ray sources. The escape length depends on energy. In relation to this, it has been reported that the ratios Ar-Fe and Ca-Fe increase above 200 GeV-n while such a tendency is not observed for K, Sc, Ti or V. Thus, no satisfactory models are available at present which can fully explain the changes in the escape length. The ratio 3 He- 4 He in the range of 5 - 10 GeV-n is inconsistent with the general theory that interprets the escape length of heavy elements. Some models, including the supermetallicity model and Wolf Rayet theory, have been proposed to explain unusual ratios of isotopes in cosmic rays, but more measurements are required to verify them. It is expected that Astromag can serve to make observations that can clarify these points. (Nogami, K.)

  13. SEM and elemental analysis of composite resins

    International Nuclear Information System (INIS)

    Hosoda, H.; Yamada, T.; Inokoshi, S.

    1990-01-01

    Twenty-four chemically cured, 21 light-cured anterior, three light-cured anterior/posterior, and 18 light-cured posterior composite resins were examined using scanning electron microscopy, and the elemental composition of their filler particles was analyzed with an energy dispersive electron probe microanalyzer. According to the results obtained, the composite resins were divided into five groups (traditional, microfilled type, submicrofilled type, hybrid type, and semihybrid), with two additional hypothetical categories (microfilled and hybrid). Characteristics of each type were described with clinical indications for selective guidance of respective composite resins for clinical use

  14. Qualitative PIXE analysis of mineral elements in some dental composites

    International Nuclear Information System (INIS)

    Preoteasa, E.A.; Iordan, Andreea; Harangus, Livia; Ciortea, C.; Gugiu, M.; Moldovan, Maria

    2002-01-01

    Dental composites, made by particles of glass, ceramics and quartz embedded in an organic polymer, develop at a high rate. However, commercial composites are expensive and recently the 'Restacril' biomaterials company became prepared to offer a low-cost alternative. The durability of dental fillings depends not only on biomaterial's gross chemical composition, but also on impurities. These may influence the chemical, mechanical and surface properties of the inorganic particles and modify the composites' clinical behavior. Thus elemental analysis is necessary to improve the biomaterials' quality. Nuclear and atomic methods allow sensitive multielement detection, and we previously analyzed some commercial composites by particle-induced X-ray emission (PIXE). Here we applied PIXE in the qualitative analysis of six new Romanian biomaterials, aiming to compare their nominal and detected composition and paying attention to the impurities. The PIXE measurements were performed with 3 MeV protons at the 8.5 MV NIPNE-HH tandem accelerator, using a hyper pure Ge detector, normal to the beam and connected to a multichannel analyzer and to a computer. Solid samples of composites with a flat surface were fixed at 45 angle, absorber foil of Al 30 mm thick was used, and integration of beam current was done. In all composites PIXE detected mineral elements with Z > 19 down to trace levels. All major nominal elements with Z > 20 - Ca, Sr, Zr, Ba, and Yb - were detected by PIXE. In addition, many minor and trace elements absent from the nominal formulations were seen, including K, Ti, Mn, Fe, Ni, Cu, Zn, Ga, Ag, Cd, Hf, and As/Pb. Such impurities may come from rough materials and preparative technologies. The impurities in Romanian composites are comparable to those in some commercial biomaterials but higher than in other ones. Thus PIXE analysis of mineral elements in Romanian composites, even qualitative, appears useful for quality control and improvement. (authors)

  15. Chinese dietary composition and element ingestion

    International Nuclear Information System (INIS)

    Zhu Hongda

    1990-01-01

    Based on the dietary composition and results of some nutrients obtained from the second Nationwide Nutrition Survey in 1982, as well as recently published element contents in various Chinese food, the resultant dietary intake of 19 kinds of elements and 17 radionuclides for Chinese public (mainly for male adults) were estimated. This estimation might be used as basis for development of Chinese Reference Man and estimation of the public background exposure

  16. Nutritional composition, antinutritional factors and elemental ...

    African Journals Online (AJOL)

    The study is aimed at evaluating nutritional composition, antinutritional factors and elemental analysis of three parts (roots sample RS, seed sample SS and leave sample LS) of Nymphaea lotus (water lily) using standard methods. The plant parts were analyzed for the content of crude lipid, crude fiber, crude proteins, ash, ...

  17. PROXIMATE AND ELEMENTAL COMPOSITION OF WHITE GRUBS

    African Journals Online (AJOL)

    DR. AMINU

    This study determined the proximate and mineral element composition of whole white grubs using standard methods of analysis. ... and 12.75 ± 3.65% respectively. Mineral contents of white grub in terms of relative concentration .... of intracellular Ca, bone mineralization, blood coagulation, and plasma membrane potential ...

  18. Elemental composition of solar energetic particles

    International Nuclear Information System (INIS)

    Cook, W.R. III.

    1981-01-01

    The Low Energy Telescopes on the Voyager spacecraft are used to measure the elemental composition (2 less than or equal to Z less than or equal to 28) and energy spectra (5 to 15 MeV/nucleon) of solar energetic particles (SEPs) in seven large flare events. Four flare events are selected which have SEP abundance ratios approximately independent of energy/nucleon. The abundances for these events are compared from flare to flare and are compared to solar abundances from other sources - spectroscopy of the photosphere and corona, and solar wind measurements. The selected SEP composition results may be described by an average composition plus a systematic flare-to-flare deviation about the average. For each of the four events, the ratios of the SEP abundances to the four-flare average SEP abundances are approximately monotonic functions of nuclear charge Z in the range 6 less than or equal to Z less than or equal to 28. An exception to this Z-dependent trend occurs for He, whose abundance relative to Si is nearly the same in all four events. The four-flare average SEP composition is significantly different from the solar composition determined by photospheric spectroscopy: the elements C, N and O are depleted in SEPs by a factor of about five relative to the elements Na, Mg, Al, Si, Ca, Cr, Fe, and Ni. For some elemental abundance ratios (e.g. Mg/O), the difference between SEP and photospheric results is persistent from flare to flare and is apparently not due to a systematic difference in SEP energy/nucleon spectra between the elements, nor to propagation effects which would result in a time-dependent abundance ratio in individual flare events

  19. Elemental composition of human and animal milk

    International Nuclear Information System (INIS)

    Iyengar, G.V.

    1982-09-01

    A review is presented of the elemental composition of human and animal milk with special reference to trace elements determined through nuclear techniques, particularly neutron activation analysis (NAA). In the joint IAEA/WHO research project, 16 of the 24 elements under investigation have been analysed by NAA with the aid of advanced research nuclear reactors. Literature data are discussed and tabulated in 50 separate tables (one for each element) mainly for the period after 1950. Each table uses a standard format comprising 10 columns indicating (1) source of milk (e.g. human or animal), (2) status of the milk (colostrum, transitional or mature), (3) country of origin, (4) year of data publication, (5) mean concentration, (6) range of single values or standard deviation of the mean, (7) number of samples analysed, (8) analytical technique employed, (9) literature source of the data, and (10) relevant remarks, if any. The most abundant data refer to the minor elements Ca, Cl, K, Mg, N, Na, P and S and to the trace elements Cu, Fe and Zn. Fewer data are available for Cd, Hg, I, Mn, Pb and Se. For the remaining elements, including such biologically important trace elements as As, Co, Cr, F, Mo, Ni, Si and Sn, very few reliable data so far appear to exist

  20. Fast XRF analysis of mineral elements in dental composites

    International Nuclear Information System (INIS)

    Preoteasa, E. A.; Constantinescu, B.; Preoteasa, E.

    2001-01-01

    Dental composites, made of particles of glass, ceramics or quartz embedded in an organic polymer matrix, extensively replaced silver amalgam in tooth fillings and enabled new applications for restorative dentistry. Long-term alteration of dental fillings together with market pressure motivates the development of composites at a high rate, largely by progress of materials forming their mineral phase. Therefore, dental composites constantly bring at the interface with enamel and dentine new elements foreign to the organism, whose biological action has not been studied. Atomic and nuclear methods for surface multielemental analysis have been used in dental research but not for composites. X-ray fluorescence (XRF) is suited for the fast microanalytical screening of the elements and of their changes at the biomaterial's surface. The potential of radioisotope-excited XRF for the analysis of dental composites has been examined. Flat disk-shaped samples of composites have been prepared and polymerized chemically or by irradiation with intense 420-500 nm light. The measurements were performed with a spectrometric chain containing a 30 mCi source of 241 Am, a Si(Li) detector, and a multichannel analyzer. The spectra were built up for 2000-6000 sec. The characteristic X lines were integrated and normalized to source lines. The following Z ≥ 20 elements were detected in the studied composites: Ba only in Charisma (Kulzer) and Pekafill (Bayer); Zr, Ba, Yb in Tetric Ceram, and Ca, Ba, Yb together with traces of possibly Ti and Fe in Ariston (both from Vivadent); Zr, Hf in Valux Plus (3M Dental); and Sr, Ba together with some trace element, seemingly Cu, in F2000 Compomer (3M Dental) and with other trace elements like Ca, Fe in Surefil (Dentsply). Among older materials, Concise (3M Dental) contained only light (Z 3 that releases F for protection of enamel and dentine. Yb, Zr, Ba, Hf improve the radiological opacity of the materials. Some elements may accompany others as

  1. Complete Subsurface Elemental Composition Measurements With PING

    Science.gov (United States)

    Parsons, A. M.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument will measure the complete bulk elemental composition of the subsurface of Mars as well as any other solid planetary body. PING can thus be a highly effective tool for both detailed local geochemistry science investigations and precision measurements of Mars subsurface reSOurces in preparation for future human exploration. As such, PING is thus fully capable of meeting a majority of both ncar and far term elements in Challenge #1 presented for this conference. Measuring the ncar subsurface composition of Mars will enable many of the MEPAG science goals and will be key to filling an important Strategic Knowledge Gap with regard to In situ Resources Utilization (ISRU) needs for human exploration. [1, 2] PING will thus fill an important niche in the Mars Exploration Program.

  2. Finite element modelling of composite castellated beam

    Directory of Open Access Journals (Sweden)

    Frans Richard

    2017-01-01

    Full Text Available Nowadays, castellated beam becomes popular in building structural as beam members. This is due to several advantages of castellated beam such as increased depth without any additional mass, passing the underfloor service ducts without changing of story elevation. However, the presence of holes can develop various local effects such as local buckling, lateral torsional buckling caused by compression force at the flange section of the steel beam. Many studies have investigated the failure mechanism of castellated beam and one technique which can prevent the beam fall into local failure is the use of reinforced concrete slab as lateral support on castellated beam, so called composite castellated beam. Besides of preventing the local failure of castellated beam, the concrete slab can increase the plasticity moment of the composite castellated beam section which can deliver into increasing the ultimate load of the beam. The aim of this numerical studies of composite castellated beam on certain loading condition (monotonic quasi-static loading. ABAQUS was used for finite element modelling purpose and compared with the experimental test for checking the reliability of the model. The result shows that the ultimate load of the composite castellated beam reached 6.24 times than the ultimate load of the solid I beam and 1.2 times compared the composite beam.

  3. Elemental compositions of two extrasolar rocky planetesimals

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.; Jura, M.; Klein, B.; Zuckerman, B. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095-1562 (United States); Koester, D., E-mail: sxu@astro.ucla.edu, E-mail: jura@astro.ucla.edu, E-mail: kleinb@astro.ucla.edu, E-mail: ben@astro.ucla.edu, E-mail: koester@astrophysik.uni-kiel.de [Institut fur Theoretische Physik und Astrophysik, University of Kiel, D-24098 Kiel (Germany)

    2014-03-10

    We report Keck/HIRES and Hubble Space Telescope/COS spectroscopic studies of extrasolar rocky planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD 133. In G29-38, eight elements are detected, including C, O, Mg, Si, Ca, Ti, Cr, and Fe while in GD 133, O, Si, Ca, and marginally Mg are seen. These two extrasolar planetesimals show a pattern of refractory enhancement and volatile depletion. For G29-38, the observed composition can be best interpreted as a blend of a chondritic object with some refractory-rich material, a result from post-nebular processing. Water is very depleted in the parent body accreted onto G29-38, based on the derived oxygen abundance. The inferred total mass accretion rate in GD 133 is the lowest of all known dusty white dwarfs, possibly due to non-steady state accretion. We continue to find that a variety of extrasolar planetesimals all resemble to zeroth order the elemental composition of bulk Earth.

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

    International Nuclear Information System (INIS)

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

    2010-01-01

    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 (P < 0.05). At one case study site, results suggested that piping and tap material can contribute to contaminant loads of harvested rainwater. 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 (P < 0.05). Similarly, zinc, lead, arsenic, strontium and molybdenum were significantly elevated in samples collected from a polyvinyl chloride pipe sampling point that does not supply household uses, compared with corresponding roof runoff samples (P < 0.05). Elemental composition was also found to vary significantly between the tank tap and an internal cold tap at one of the sites investigated, with several elements fluctuating significantly between the two outlets of interest at this site, including potassium, zinc, manganese, barium, copper, vanadium, chromium and arsenic. These results highlighted the variability in the elemental composition of collected 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.

  5. Pluto's surface composition and atmosphere

    Science.gov (United States)

    Young, L. A.; Gladstone, R.; Summers, M. E.; Strobel, D. F.; Kammer, J.; Hinson, D. P.; Grundy, W. M.; Cruikshank, D. P.; Protopapa, S.; Schmitt, B.; Stern, A.; Weaver, H. A., Jr.; Olkin, C.; Ennico Smith, K.

    2017-12-01

    New Horizons studied Pluto's N2-dominated neutral atmosphere through radio (at 4.2 cm with the REX radio experiment), solar and stellar occultations and airglow (at 52-187 nm with the Alice ultraviolet spectrograph), and imaging (with the LORRI and MVIC visible-wavelength cameras). It studied the plasma environment and solar wind interaction with in situ instruments (PEPPSI and SWAP). Contemporaneous observations of Pluto's atmosphere from Earth included a ground-based stellar occultation and ALMA observations of gaseous CO and HCN. Joint analysis of these datasets reveal a variable boundary layer; a stable lower atmosphere; radiative heating and cooling; haze production and hydrocarbon chemistry; diffusive equilibrium; and slower-than-expected escape. New Horizons studied Pluto's surface composition with the LEISA near-infrared spectral imager from 1.25 to 2.5 micron. Additional compositional information at higher spatial resolution came from the MVIC 4-channel color imager, which included a channel centered at 0.89 micron specifically designed to detect solid CH4. These instruments allow mapping of the volatiles N2, CO, and CH4, the surface expression of the H2O bedrock, and the dark, reddish material presumed to be tholins. These observations reveal a large equatorial basin (informally named Sptunik Planitia), filled with N2 ice with minor amounts of CO and CH4, surrounded by hills of CH4 and H2O ice. Broadly speaking, composition outside of Sptunik Planitia follows latitudinal banding, with dark, mainly volatile free terrains near the equator, with N2, CO, and CH4 at mid-northern latitudes, and mainly CH4 at high northern latitudes. Deviations from these broad trends are seen, and point to complex surface-atmosphere interactions at diurnal, seasonal, perennial, and million-year timescales.

  6. 23 Elemental Composition of Suspended Particulate Matter ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    The samples were analysed by energy dispersive x-ray fluorescence. (EDXRF) and atomic absorption spectroscopy (AAS) for up to 10 elements. It was found that 66% of the ..... coefficients between the various crustal elements Ca, Ti, Mn, ...

  7. Composite elements with superconducting ceramic materials and preparation process

    International Nuclear Information System (INIS)

    Drifford, M.; Lambard, J.

    1990-01-01

    Supraconducting ceramic powder is introduced in a ductile metal with an open porosity, then the tube is sealed at both ends and necked to form a composite element which is sintered and the ceramic becomes superconductive by gaseous diffusion. Then the composite element can be placed into a gasproof cladding [fr

  8. 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.

  9. 0 Elemental Composition of Atmospheric Particulate Matter during ...

    African Journals Online (AJOL)

    Michael Horsfall

    ABSTRACT: The elemental composition of PM10 was studied during 2006 wet season in a rural background ... reference of crustal material, showed that for the coarse size fraction, most .... particular sector was made using criteria similar to.

  10. Elemental composition of commercial sea cucumbers (holothurians).

    Science.gov (United States)

    Wen, J; Hu, C

    2010-01-01

    Toxic and essential elements in 11 different sea cucumber species were determined and compared with daily intake recommendations and maximum allowed levels. The contents of macro-elements contents in dried sea cucumber samples were found to be 25,000-152,000 mg kg(-1) for Na, 4000-8600 mg kg(-1) for Mg, 1100-5200 mg kg(-1) for K, 15,000-68,000 mg kg(-1) and 36,300-251,000 mg kg(-1) for Cl. Trace element concentrations in dried sea cucumber samples were found to be 11-100 mg kg(-1) for Zn, 41-660 mg kg(-1) for Fe, 3-74 mg kg(-1) for Cu, 1.1-16 mg kg(-1) for Mn, 1.4-3.7 mg kg(-1) for Se, 1.1-9.6 mg kg(-1) for Cr, and 0.3-5.1 mg kg(-1) for Ni. All sea cucumber species were rich sources of Na, Cl, Mg, Ca, Fe, Cu, Se and Cr for human consumption. Regarding contaminants, As, Cd and Pb concentrations in dried sea cucumbers were in the ranges of 1.1-6.1, 0.03-0.06 and 0.11-0.69 mg kg(-1), respectively. Moreover, Hg values of 11 sea cucumbers were below the detection limit (0.01 mg kg(-1)).

  11. Experimental study on effect of flux composition on element transfer ...

    Indian Academy of Sciences (India)

    BRIJPAL SINGH

    2018-03-10

    Mar 10, 2018 ... 3 Division of Manufacturing Processes and Automation Engineering, Netaji Subhas Institute of ... Submerged arc welding; basicity index; element transfer; slag metal reactions; oxidizing power of ... flux composition, wire and base plate composition. ..... increase in BI of the flux with increasing NiO additive. If.

  12. Surface composition and surface properties of water hyacinth ...

    African Journals Online (AJOL)

    Surface composition and surface properties of water hyacinth ( Eichhornia ... (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, ... polar organic solvents and non-polar n-alkane hydrocarbons is discussed.

  13. Visualizing Composite Data on the Lexis Surface

    DEFF Research Database (Denmark)

    Schöley, Jonas; Willekens, Frans

    The analysis of composite data is a topic inherent to demography. In recent times, due to a growing catalogue of detailed population data, it became feasible to consider populations not only structured by time, age or sex, but by any number of interesting criteria. This “inflation” of data...... dimensions produces challenges in visualizing the data. To aid the understanding of age-structured timelines of compositions we seek to extend the Lexis surface plot from 1-dimensional continuous data to multidimensional composite data. We apply different strategies for visualizing composite data...

  14. 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.

  15. Composition of bracken: some major- and trace-element constituents

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, J G

    1953-01-01

    Periodic samples of bracken taken during the growing season have shown that the concentration of major elements (except calcium and sodium) decreases with age in fronds, and remains relatively constant in rhizomes, whereas trace-element concentration varies widely. Soil type has little effect on the mineral composition of fronds. Examination of three rhizome types revealed no wide differences in the content of major elements; pinnules generally contained higher concentrations of major and trace elements than fronds. Comparison of results with those published elsewhere for moorland plants grown under similar conditions indicates that bracken contains more potassium and less molybdenum.

  16. The Origin of Mercury's Surface Composition, an Experimental Investigation

    Science.gov (United States)

    Boujibar, A.; Righter, K.; Rapp, J. F.; Ross, D. K.; Pando, K. M.; Danielson, L. R.; Fontaine, E.

    2016-01-01

    Introduction: Results from MESSENGER spacecraft have confirmed the reduced nature of Mercury, based on its high core/mantle ratio and its FeO-poor and S-rich surface. Moreover, high resolution images revealed large volcanic plains and abundant pyroclastic deposits, suggesting major melting stages of the Mercurian mantle. In addition, MESSENGER has provided the most precise data to date on major elemental compositions of Mercury's surface. These results revealed considerable chemical heterogeneities that suggested several stages of differentiation and re-melting processes. This interpretation was challenged by our experimental previous study, which showed a similar compositional variation in the melting products of enstatite chondrites, which are a possible Mercury analogue. However, these experimental melts were obtained over a limited range of pressure (1 bar to 1 gigapascal) and were not compared to the most recent elemental maps. Therefore, here we extend the experimental dataset to higher pressures and perform a more quantitative comparison with Mercury's surface compositions measured by MESSENGER. In particular, we test whether these chemical heterogeneities result from mixing between polybaric melts. Our experiments and models show that the majority of chemical diversity of Mercury's surface can result from melting of a primitive mantle compositionally similar to enstatite chondrites in composition at various depths and degrees of melting. The high-Mg region's composition is reproduced by melting at high pressure (3 gigapascals) (Tab. 1), which is consistent with previous interpretation as being a large degraded impact basin based on its low elevation and thin average crust. While low-Mg NVP (North Volcanic Plains) are the result of melting at low pressure (1 bar), intermediate-Mg NVP, Caloris Basin and Rachmaninoff result from mixing of a high-pressure (3 gigapascals) and low-pressure components (1 bar for Rachmaninoff and 1 gigapascal for the other regions

  17. Finite Elements on Point Based Surfaces

    NARCIS (Netherlands)

    Clarenz, U.; Rumpf, M.; Telea, A.

    2004-01-01

    We present a framework for processing point-based surfaces via partial differential equations (PDEs). Our framework efficiently and effectively brings well-known PDE-based processing techniques to the field of point-based surfaces. Our method is based on the construction of local tangent planes and

  18. Visualizing compositional data on the Lexis surface

    DEFF Research Database (Denmark)

    Schöley, Jonas; Willekens, Frans

    2017-01-01

    the visualizations for compliance with multiple desired criteria. Results: Compositional data can effectively be visualized on the Lexis surface. A key feature of the classical Lexis surface plot – to show age, period, and cohort patterns – is retained in the domain of compositions. The optimal choice among the four...... and demonstrate the usefulness of the techniques by performing an exploratory analysis of age-specific French cause-of-death patterns across the 20th century. We identify strengths and weaknesses of the four proposed techniques. We contribute a technique to construct the ternary-balance colour scheme from within...

  19. SAFE-3D, Stress Analysis of 3-D Composite Structure by Finite Elements Method

    International Nuclear Information System (INIS)

    Cornell, D.C.; Jadhav, K.; Crowell, J.S.

    1969-01-01

    1 - Description of problem or function: SAFE-3D is a finite-element program for the three-dimensional elastic analysis of heterogeneous composite structures. The program uses the following types of finite elements - (1) tetrahedral elements to represent the continuum, (2) triangular plane stress membrane elements to represent inner liner or outer case, and (3) uniaxial tension-compression elements to represent internal reinforcement. The structure can be of arbitrary geometry and have any distribution of material properties, temperatures, surface loadings, and boundary conditions. 2 - Method of solution: The finite-element variational method is used. Equilibrium equations are solved by the alternating component iterative method. 3 - Restrictions on the complexity of the problem - Maxima of: 5000 nodes; 16000 elements. The program cannot be applied to incompressible solids and is not recommended for Poisson's ratio in the range of nu between 0.495 and 0.5

  20. Visualizing compositional data on the Lexis surface

    Directory of Open Access Journals (Sweden)

    Jonas Schöley

    2017-02-01

    Full Text Available Background: The Lexis surface plot is an established visualization tool in demography. Its presentutility, however, is limited to the domain of one-dimensional magnitudes such as ratesand counts. Visualizing proportions among three or more groups on a period-age grid isan unsolved problem. Objective: We seek to extend the Lexis surface plot to the domain of compositional data. Methods: We propose four techniques for visualizing group compositions on a period-age grid. Todemonstrate the techniques we use data on age-specific cause-of-death compositions inFrance from 1925 to 1999. We compare the visualizations for compliance with multipledesired criteria. Results: Compositional data can effectively be visualized on the Lexis surface. A key feature ofthe classical Lexis surface plot - to show age, period, and cohort patterns - is retainedin the domain of compositions. The optimal choice among the four proposed techniquesdepends primarily on the number of groups making up the composition and whether ornot the plot should be readable by people with impaired colour vision. Contribution: We introduce techniques for visualizing compositional data on a period-age grid to thefield of demography and demonstrate the usefulness of the techniques by performingan exploratory analysis of age-specific French cause-of-death patterns across the 20thcentury. We identify strengths and weaknesses of the four proposed techniques. We contribute a technique to construct the ternary-balance colour scheme from within a per-ceptually uniform colour space. Comments: A full-colour representation is key to understanding the paper. Therefore, we recommend that you read it on screen or print a colour version.

  1. Surface composition of Mercury from reflectance spectrophotometry

    Science.gov (United States)

    Vilas, Faith

    1988-01-01

    The controversies surrounding the existing spectra of Mercury are discussed together with the various implications for interpretations of Mercury's surface composition. Special attention is given to the basic procedure used for reducing reflectance spectrophotometry data, the factors that must be accounted for in the reduction of these data, and the methodology for defining the portion of the surface contributing the greatest amount of light to an individual spectrum. The application of these methodologies to Mercury's spectra is presented.

  2. 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

  3. Dynamic analysis of smart composite beams by using the frequency domain spectral element method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Il Wook; Lee, Usik [Inha Univ., Incheon (Korea, Republic of)

    2012-08-15

    To excite or measure the dynamic responses of a laminated composite structure for the active controls of vibrations or noises, wafertype piezoelectric transducers are often bonded on the surface of the composite structure to form a multi layer smart composite structure. Thus, for such smart composite structures, it is very important to develop and use a very reliable mathematical and/or computational model for predicting accurate dynamic characteristics. In this paper, the axial-bending coupled equations of motion and boundary conditions are derived for two layer smart composite beams by using the Hamilton's principle with Lagrange multipliers. The spectral element model is then formulated in the frequency domain by using the variation approach. Through some numerical examples, the extremely high accuracy of the present spectral element model is verified by comparing with the solutions by the conventional finite element model provided in this paper. The effects of the lay up of composite laminates and surface bonded wafer type piezoelectric (PZT) layer on the dynamics and wave characteristics of smart composite beams are investigated. The effective constraint forces at the interface between the base beam and PZT layer are also investigated via Lagrange multipliers.

  4. Elemental compositions of suspended particles released in glass manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Mamuro, T; Mizohata, A; Kubota, T [Radiation Center of Osaka Prefecture, Sakai (Japan)

    1980-03-01

    Suspended particles released in glass manufacture were subjected to multielement analysis by means of instrumental neutron activation method and energy dispersive X-ray fluorescence spectrometry. Suspended particles emitted from glass manufacture generally consist of both particles emitted from glass fusion and those produced through fuel combustion (mainly oil combustion). Elemental compositions of suspended particles emitted from glass fusion were found to be strongly dependent on the kind and recipe of raw materials and additives. Of the various metallic elements involved in suspended particles emitted from glass fusion, the elements, As, Se, Cd, Sb, Pb and so on are regarded to produce the most serious air pollution. The amount of emission of these elements to the environment is, howerer, quite varied from manufacturer to manufacturer. The replacement of electric furnace by oil combustion in opal glass manufacture remarkably reduced the emission of metallic elements to the environment.

  5. PIXE analysis of trace and other mineral elements in Romanian dental composites

    International Nuclear Information System (INIS)

    Preoteasa, E. A.; Iordan, Andreea; Harangus, Livia; Ciortea, C.; Moldovan, Maria

    2002-01-01

    Dental composites made of silicates and oxides particles embedded in an organic polymer, show a dynamic evolution but are rather expensive. Recently, the Romanian biomaterial 'Restacril' offered a low-cost alternative. Because the durability of the composite dental fillings depends both on the main chemical composition and on the impurities that may influence the inorganic particles' properties and thus modifying the bio material clinical behaviour, the elemental analysis of the material is necessary for improving its quality. Particle-induced X-ray emission (PIXE), a sensitive method for multielemental trace detection widely used in biomedical applications, allowed us to evidence 21 mineral elements with Z > 14 in some commercial dental composites. Here we evaluate the performances of PIXE for the control of dental composites by carrying out qualitative analysis of three Romanian biomaterials. PIXE measurements on thick composite samples with a flat surface were done with 3 MeV protons at the NIPNE-HH (Horia Hulubei National Institute for Physics and Nuclear Engineering) tandem accelerator, using a hyper-pure Ge detector, 30 mm thick Al absorber foil and integration of beam current. Up to 21 elements with Z > 19 were detected: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Ga, Sr, Zr, Nb, Ru, Ag, Ba, Yb, Nd, Hf, Au, As and Pb. The orders of magnitude of relative concentrations were evaluated using X-ray yields obtained for another light element thick composite target. The Romanian composites have specific and diverse compositions, containing a great number of minor and trace elements, many of whom are impurities. Use of higher purity raw materials is suggested to reduce the latter and improve the materials' quality. Refinement of X-ray yields by better matching matrixes calculations and use of concentration standards are proposed for quantitative PIXE analysis of the dental composites. (authors)

  6. Comment on 'Modelling of surface energies of elemental crystals'

    International Nuclear Information System (INIS)

    Li Jinping; Luo Xiaoguang; Hu Ping; Dong Shanliang

    2009-01-01

    Jiang et al (2004 J. Phys.: Condens. Matter 16 521) present a model based on the traditional broken-bond model for predicting surface energies of elemental crystals. It is found that bias errors can be produced in calculating the coordination numbers of surface atoms, especially in the prediction of high-Miller-index surface energies. (comment)

  7. Proximate and mineral elements composition of five locally ...

    African Journals Online (AJOL)

    The proximate composition of the studied fruits were determined by the standard methods of Official Analytical Chemists, while the Mineral Elements (Ca and Mg) were analyzed using Atomic Absorption Spectrophotometry. The levels of Na+ and K+ were determined using Flame photometry and the level of P was ...

  8. Effect of Processing on the Elemental Composition of Selected Leafy ...

    African Journals Online (AJOL)

    The elemental composition of leaves of Vernonia amygdalina, Gnetum africana, Gongronema latifolium and Ocimum gratissimum subjected to different processing methods were investigated. Processing methods employed include oven drying, sun drying, fresh milling, steaming and a combination of these while the mineral ...

  9. Machining of Machine Elements Made of Polymer Composite Materials

    Science.gov (United States)

    Baurova, N. I.; Makarov, K. A.

    2017-12-01

    The machining of the machine elements that are made of polymer composite materials (PCMs) or are repaired using them is considered. Turning, milling, and drilling are shown to be most widely used among all methods of cutting PCMs. Cutting conditions for the machining of PCMs are presented. The factors that most strongly affect the roughness parameters and the accuracy of cutting PCMs are considered.

  10. COMPOSITE FRIEND SISAL / POLYESTER TREATED IN SURFACE

    Directory of Open Access Journals (Sweden)

    Jayna K. Dionisio Santos

    2011-09-01

    Full Text Available The use of composites in manufacturing equipment and products is taking a very important space in the industry in general. Moreover these materials have unique characteristics when analyzed separately from constituents who are part of them. However it is know that cares must be taken in their manufacture, as the use of appropriate process and the composition of each element, in addition to adherence fiber / matrix, which is a major factor in obtaining of the final mechanical strength of the product. One should also take into account whether the composites are environmentally friendly. For this reason, in this work, a composite partially ecological was made, using as reinforcement, a sisal woven and, as matrix, the polyester resin. Seeking to improve the adherence fiber / matrix, a treatment in sisal woven was performed with aqueous solution of sodium hydroxide (NaOH at a concentration of 3%. The composite subjected to this treatment presented, in bending test, a better mechanical performance, with an increase of 27% in the flexion strength and of 54% in maximum strain, but there was a reduction of about 15% in its flexural modulus.

  11. Finite elements modeling of delaminations in composite laminates

    DEFF Research Database (Denmark)

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

    2011-01-01

    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......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., delaminations, which may affect the stiffness and stability of structural components. Especially deep delaminations in the mid surface of laminates are expected to reduce the effective flexural stiffness and lead to collapse, often due to buckling behaviour. This paper deals with the numerical modelling...

  12. Elemental composition and oxidation of chamber organic aerosol

    Directory of Open Access Journals (Sweden)

    P. S. Chhabra

    2011-09-01

    Full Text Available Recently, graphical representations of aerosol mass spectrometer (AMS spectra and elemental composition have been developed to explain the oxidative and aging processes of secondary organic aerosol (SOA. It has been shown previously that oxygenated organic aerosol (OOA components from ambient and laboratory data fall within a triangular region in the f44 vs. f43 space, where f44 and f43 are the ratios of the organic signal at m/z 44 and 43 to the total organic signal in AMS spectra, respectively; we refer to this graphical representation as the "triangle plot." Alternatively, the Van Krevelen diagram has been used to describe the evolution of functional groups in SOA. In this study we investigate the variability of SOA formed in chamber experiments from twelve different precursors in both "triangle plot" and Van Krevelen domains. Spectral and elemental data from the high-resolution Aerodyne aerosol mass spectrometer are compared to offline species identification analysis and FTIR filter analysis to better understand the changes in functional and elemental composition inherent in SOA formation and aging. We find that SOA formed under high- and low-NOx conditions occupy similar areas in the "triangle plot" and Van Krevelen diagram and that SOA generated from already oxidized precursors allows for the exploration of areas higher on the "triangle plot" not easily accessible with non-oxidized precursors. As SOA ages, it migrates toward the top of the triangle along a path largely dependent on the precursor identity, which suggests increasing organic acid content and decreasing mass spectral variability. The most oxidized SOA come from the photooxidation of methoxyphenol precursors which yielded SOA O/C ratios near unity. α-pinene ozonolysis and naphthalene photooxidation SOA systems have had the highest degree of mass closure in previous chemical characterization studies and also show the

  13. Constraints on Europa's Ocean Composition Imposed by Its Surface Composition

    Science.gov (United States)

    Johnson, P. V.; Hodyss, R. P.; Vu, T. H.; Choukroun, M.

    2017-12-01

    Of the non-terrestrial environments within our Solar System, Europa's global liquid water ocean is arguably the most likely to be habitable. As such, understanding the habitability of Europa's ocean is of great interest to astrobiology and is the focus of missions currently being considered for further exploration of Europa. However, direct analysis of the ocean is unlikely in the foreseeable future. As such, our best means of constraining the subsurface ocean composition and its subsequent habitability currently is by further study of Europa's surface chemical composition. Recently, there has been a body of work published that looks at the chemistry of frozen brines representing putative ocean compositions. Here we take a simplified model of a four ionic component (Na, Mg, SO4, Cl) solution and map out what minerals are formed upon freezing as a function of relative ionic concentration, pH, etc. A `flow-chart' of the freezing sequence was developed based on both published and recently acquired experimental results. In performing this exercise, we are able to begin making meaningful links between observations of the surface chemistry and the chemical environment of the internal ocean.

  14. Analytical and statistical analysis of elemental composition of lichens

    International Nuclear Information System (INIS)

    Calvelo, S.; Baccala, N.; Bubach, D.; Arribere, M.A.; Riberio Guevara, S.

    1997-01-01

    The elemental composition of lichens from remote southern South America regions has been studied with analytical and statistical techniques to determine if the values obtained reflect species, growth forms or habitat characteristics. The enrichment factors are calculated discriminated by species and collection site and compared with data available in the literature. The elemental concentrations are standardized and compared for different species. The information was statistically processed, a cluster analysis was performed using the three first principal axes of the PCA; the three groups formed are presented. Their relationship with the species, collection sites and the lichen growth forms are interpreted. (author)

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    This paper deals with the mechanical behavior under in plane compressive loading of thick and mostly unidirectional glass fiber composite plates made with an initial embedded delamination. The delamination is rectangular in shape, causing the separation of the central part of the plate into two...... 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...

  16. Elemental composition changes in citrus affected by the CVC disease

    International Nuclear Information System (INIS)

    Nadai Fernandes de, A.A.; Tagliaferro, F.S.; Turra, C.; Franca de, E.J.; Bacchi, M.A.

    2008-01-01

    The citrus variegated chlorosis (CVC) disease results in serious economical losses for the Brazilian citriculture. The influence of CVC disease on the elemental composition of citrus plants was investigated. Leaves of sweet orange varieties Hamlin, Pera Rio and Valencia were collected from healthy and CVC-affected trees for chemical characterization by instrumental neutron activation analysis (INAA). Significant differences between healthy and CVC-affected leaves were identified for Ca, Ce, Co, Eu, Fe, K, La, Na, Nd, Rb, Sc and Sm. Rare earth elements presented consistently higher mass fractions in the healthy leaves. (author)

  17. Surface Preparation for Microdebonding Analysis of Composites

    International Nuclear Information System (INIS)

    Kahraman, Ramazan; Mandell, J. F.

    1999-01-01

    The bond strength between fibers and matrix is an essential property of all composite materials and it must be measured accurately to be able to correlate it with the composite behavior. There are several factors affecting its measurement. This paper discusses the polishing and load application aspects of the indentation test technique for fibre-matrix bond strength determination in polymer and ceramic matrix composites. Different polishing procedures are suggested for polymer and ceramic surfaces for obtaining a smooth surface which is a must for the test results to be reliable. The geometry of the fibers tested was also found to affect the analysis results. For best results, fibers with similar size and which are similarly surrounded by other fibers should be tested. Care should be taken during load application on a fiber for the loading probe not to approach the fiber circumference. The force should be applied in a small increments as possible, however starting from a high enough level to prevent fiber breakage due to surface damage from several loading steps. (Author)

  18. Mapping chemical elements on the surface of orthodontic appliance by SEM-EDX.

    Science.gov (United States)

    Mikulewicz, Marcin; Wołowiec, Paulina; Michalak, Izabela; Chojnacka, Katarzyna; Czopor, Wojciech; Berniczei-Royko, Adam; Vegh, Andras; Gedrange, Thomas

    2014-05-25

    During orthodontic treatment, the various elements that constitute the fixed appliance undergo different processes. As a result of a change of the surface, elution/coverage of metals on the surface can be observed in the process of corrosion/passivation. Scanning electron microscopy with an energy-dispersive X-ray analytical system (SEM-EDX) was used to analyze the composition of stainless steel elements of orthodontic fixed appliances (before and after orthodontic treatment), to obtain the composition of the surface of the elements. The analyzed elements were: brackets (Victory Series APC PLUS 022, 3M Unitek, Monrovia, CA, USA); wires (0.017×0.025, 3M Unitek, Monrovia, CA, USA); and bands (37+, 3M Unitek, Monrovia, CA, USA). The results showed a decrease of chromium and iron contribution to the surface, with increase of oxygen content in used vs. new elements of the appliance. Our results confirm the formation of oxides (passivation layer) on the surface of stainless steel as a result of the presence of the orthodontic appliance in patients' oral cavities.

  19. (90377) SEDNA: INVESTIGATION OF SURFACE COMPOSITIONAL VARIATION

    International Nuclear Information System (INIS)

    Barucci, M. A.; De Bergh, C.; Merlin, F.; Morea Dalle Ore, C.; Cruikshank, D.; Alvarez-Candal, A.; Dumas, C.

    2010-01-01

    The dwarf planet (90377) Sedna is one of the most remote solar system objects accessible to investigations. To better constrain its surface composition and to investigate the possible heterogeneity of the surface of Sedna, several observations have been carried out at ESO-VLT with the powerful spectrometer SINFONI observing simultaneously the H and K bands. The analyzed spectra (obtained in 2005, 2007, and 2008) show a non-uniform spectral signature, particularly in the K band. Spectral modeling using the Shkuratov radiative transfer code for surface scattering has been performed using the various sets of data, including previous observations at visible wavelengths and photometry at 3.6 and 4.5 μm by the Spitzer Space Telescope. The visible and near-infrared spectra can be modeled with organic materials (triton and titan tholin), serpentine, and H 2 O ice in fairly significant amounts, and CH 4 , N 2 , and C 2 H 6 in varying trace amounts. One of the spectra obtained in 2005 October shows a different signature in the K band and is best modeled with CH 3 OH in place of CH 4 , with reduced amounts of serpentine and with the addition of olivine. The compositional surface heterogeneity can give input on the past history as well clues to the origin of this peculiar, distant object.

  20. Chemical composition and mineral elements of edible insects (at ...

    African Journals Online (AJOL)

    The Chemical Composition and Mineral Elements of two edible insects' larvae and termite soldiers were assayed. Their ash content were between 1.01% and 7.50%. The legless larva (LS) had 28.52% fat, while the solider ant had 7.14% and the Legged larva (LG) had 1.50%. The white ant (SA) had 15.61% protein while ...

  1. Towards improved modeling of steel-concrete composite wall elements

    International Nuclear Information System (INIS)

    Vecchio, Frank J.; McQuade, Ian

    2011-01-01

    Highlights: → Improved analysis of double skinned steel concrete composite containment walls. → Smeared rotating crack concept applied in formulation of new analytical model. → Model implemented into finite element program; numerically stable and robust. → Models behavior of shear-critical elements with greater ease and improved accuracy. → Accurate assessments of strength, deformation and failure mode of test specimens. - Abstract: The Disturbed Stress Field Model, a smeared rotating crack model for reinforced concrete based on the Modified Compression Field Theory, is adapted to the analysis of double-skin steel-concrete wall elements. The computational model is then incorporated into a two-dimensional nonlinear finite element analysis algorithm. Verification studies are undertaken by modeling various test specimens, including panel elements subject to uniaxial compression, panel elements subjected to in-plane shear, and wall specimens subjected to reversed cyclic lateral displacements. In all cases, the analysis model is found to provide accurate calculations of structural load capacities, pre- and post-peak displacement responses, post-peak ductility, chronology of damage, and ultimate failure mode. Minor deficiencies are found in regards to the accurate portrayal of faceplate buckling and the effects of interfacial slip between the faceplates and the concrete. Other aspects of the modeling procedure that are in need of further research and development are also identified and discussed.

  2. Elemental composition of urban aerosol collected in Florence, Italy

    International Nuclear Information System (INIS)

    Lucarelli, F.; Mando, P.A.; Nava, S.; Prati, P.; Zucchiatti, A.

    2000-01-01

    An extensive investigation is in progress aiming at the characterisation of the air particulate composition in Florence. The aim is to determine the aerosol elemental concentrations as well to identify pollution sources. For our investigation, we use the external PIXE-PIGE beam facility of the Van de Graaff accelerator of INFN at the Physics Department of the Florence University. We report here an overview of the results of the PIXE analysis of a long temporal series (about 1 yr) of PM 10 particulate collected on Millipore filters on a daily basis in three different sites (characterised by different urban settings). Daily concentrations of more than 20 elements have been obtained. From the observed elemental concentrations seasonal variation were found. A relevant decrease of S, Pb and Br levels has been found with respect to 10 yr ago. Four main sources (traffic, sulphates, soil-dust and wind-transported sea-salt) have been extracted with the help of factor analysis

  3. Finite element modelling and analysis of composites toecaps

    International Nuclear Information System (INIS)

    Yang, C C; Duhovic, M; Lin, R J T; Bhattacharyya, D

    2009-01-01

    Composite toe-caps have attracted considerable attention due to their advantageous properties over traditional metallic toe-caps. However, the anisotropic properties of composite materials also make the toe-cap performance more complex to analyse. This project aims at developing a Finite Element (FE) model for composite toe-caps with the aid of compression testing data. The geometry of the toe-cap was first scanned and imported into an FEA software package to create a workable FE model. The method was then validated by comparing the FE model with experimental results of steel toe-caps. Manufacturing, modelling and testing of custom-made composite toe-cap samples were then carried out. Modelling outputs of composite toe-caps were compared with compression test data for validation. The stress distributions and deformations of the toe-caps were also analysed. Modelling of the steel and composite toe-caps was realized using LS-DYNA Solver and PrePost (registered) . All FE analyses were modelled with reference to European Standards. The developed FE models can in the future be used to model toe-caps with various materials to determine the effects of fibre orientation relating to structural strength, and to achieve structural optimisation.

  4. Hierarchical clustering into groups of human brain regions according to elemental composition

    International Nuclear Information System (INIS)

    Stedman, J.D.; Spyrou, N.M.

    1998-01-01

    Thirteen brain regions were dissected from both hemispheres of fifteen 'normal' ageing subjects (8 females, 7 males) of mean age 79±7 years. Elemental compositions were determined by simultaneous application of particle induced X-ray emission (PIXE) and Rutherford backscattering (RBS) analyses using a 2 MeV, 4 nA proton beam scanned over 4 mm 2 of the sample surface. Elemental concentrations were found to be dependent upon the brain region and hemisphere studied. Hierarchical cluster analysis was applied to group the brain regions according to the sample concentrations of eight elements. The resulting dendrogram is presented and its clusters related to the sample compositions of grey and white matter. (author)

  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. Producing of multicomponent and composite surface layers

    International Nuclear Information System (INIS)

    Wierzchon, T.; Bielinski, P.; Michalski, A.

    1995-01-01

    The paper presents a new method of producing multicomponent and composite layers on steel substrate. The combination of nickel plating with glow-discharge bordering or impulse-plasma deposition method gives an opportunity to obtain good properties of surface layers. The results of examinations of carbon 45 (0.45%C) steel, nickel plated and then borided under glow discharge conditions or covered with TiN layers are presented. The corrosion and friction wear resistance of such layers are markedly higher than for layer produced on non nickel plated substrates. (author). 19 refs, 5 figs

  7. Mineral elements in dental composites by atomic and nuclear analytical methods. I. Fast analysis by XRY

    International Nuclear Information System (INIS)

    Preoteasa, E.A.; Constantinescu, B.; Preoteasa, Elena

    2000-01-01

    Composite materials replaced silver amalgam in many applications for restorative dentistry. Among biomaterials their production develops at a high rate, due especially to the progress of materials forming their mineral filling. However they bring at the interface with enamel and dentine elements foreign to the organism, of whom not all are specified by manufacturers; also, some of these elements' biological action has not been studied. Due to its ability to analyze the elemental composition at the biomaterial's surface, as well as the concentration changes that may occur in the mouth or in model systems, X-ray fluorescence (XRF) is a method suited to approach such problems. Here we examined the potential of XRF for fast analysis of some dental composite materials. Flat disk-shaped samples have been prepared by polymerization and the measurements have been performed with a spectrometric chain containing a 241 Am source, a Si(Li) detector and a multichannel analyzer. The radioisotope-excited XRF detected the following Z > 20 elements in the studied composite materials: Ba in Charisma (Kulzer) and Pekafill (Bayer); Zr, Ba, Yb [and traces of In] in Tetric Ceram (Vivadent); Zr, Hf in Valux Plus and Sr, Ba and traces of Cu in F2000 compomer (both from 3M Dental). Among older materials, Evicrol (Spofa) and Alphaplast (DGM) showed Ca and Fe, while Concise (3M Dental) contained only undetectable (Z < 20) elements. XRF proved valuable especially for analysis of major and minor inorganic elements in the dental composite materials. The method could be used also in fast expertise of these biomaterials (e.g. in customs and commercial applications). (authors)

  8. Roughness analysis of graphite surfaces of casting elements

    Directory of Open Access Journals (Sweden)

    M. Wieczorowski

    2010-01-01

    Full Text Available In the paper profilometric measurements of graphite casting elements were described. Basic topics necessary to assess roughness of their surfaces and influence of asperities on various properties related to manufacturing and use were discussed. Stylus profilometer technique of surface irregularities measurements including its limits resulting from pickup geometry and its contact with measured object were ana-lyzed. Working principle of tactile profilometer and phenomena taking place during movement of a probe on a measured surface were shown. One of the important aspects is a flight phenomenon, which means movement of a pickup without contact with a surface during inspection resulting from too high scanning speed. results of comparison research for graphite elements of new and used mould and pin composing a set were presented. Using some surface roughness, waviness and primary profile parameters (arithmetical mean of roughness profile heights Ra, biggest roughness profile height Rz, maximum primary profile height Pt as well as maximum waviness profile height Wt a possibility of using surface asperities parameters as a measure of wear of chill graphite elements was proved. The most often applied parameter is Ra, but with a help of parameters from W and P family it was shown, that big changes occur not only for roughness but also for other components of surface irregularities.

  9. 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.

  10. Wavelet Spectral Finite Elements for Wave Propagation in Composite Plates

    Science.gov (United States)

    2012-02-21

    aerospace structures is increasing rapidly due to several advantages such as lighter weight, fewer joints, improved fatigue life, and higher...breakage, and matrix cracking. These damages often occur below the surface due to fatigue , foreign object impact, etc., and may not be visible. The...ply [0/90]2s. A piezoelectric ( PZT ) actuator (diameter 13.5 mm and thickness 0.22 mm) is affixed onto the composite plate using epoxy. A National

  11. 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.

  12. Influence of Layup Sequence on the Surface Accuracy of Carbon Fiber Composite Space Mirrors

    Science.gov (United States)

    Yang, Zhiyong; Liu, Qingnian; Zhang, Boming; Xu, Liang; Tang, Zhanwen; Xie, Yongjie

    2018-04-01

    Layup sequence is directly related to stiffness and deformation resistance of the composite space mirror, and error caused by layup sequence can affect the surface precision of composite mirrors evidently. Variation of layup sequence with the same total thickness of composite space mirror changes surface form of the composite mirror, which is the focus of our study. In our research, the influence of varied quasi-isotropic stacking sequences and random angular deviation on the surface accuracy of composite space mirrors was investigated through finite element analyses (FEA). We established a simulation model for the studied concave mirror with 500 mm diameter, essential factors of layup sequences and random angular deviations on different plies were discussed. Five guiding findings were described in this study. Increasing total plies, optimizing stacking sequence and keeping consistency of ply alignment in ply placement are effective to improve surface accuracy of composite mirror.

  13. The study of the elemental composition of peppermint (Mentha piperita

    Directory of Open Access Journals (Sweden)

    K. V. Andrianov

    2014-12-01

    Full Text Available Introduction Our attention was drawn by quite widespread plant, namely peppermint (Mentha piperita of mint family (Lamiaceae L.. It isn’t known as a wild-growing plant, this plant is the hybrid received from crossing water mint (Mentha aquatica with a spicate mint (Mentha spicata or green mint (Mentha viridis. Therapeutic action of plant is caused by the BAS complex, among which essential oil, alkaloids, saponins, organic acids, vitamins, macro - and microelements are. Accumulation of elements in a plant directly depends on sort and species of this plant, climatic conditions and geographical places of growth. Thus, using pharmacognosic research of peppermint, it would be expedient to carry out the comparative analysis of the elements content in leaf of widespread species of this plant, and also to compare to element structure of peppermint from other region of preparation. Studying qualitative structure and quantitative content of macro - and microelements in leaf of 3 samples of peppermint became the purpose of our research. Materials and methods of research The peppermint leaves of 3 samples were the object of our research. They are ‘Chornolistaya’ sort – the sample #1, ‘Zgadka’ sort – the sample #2 (the stocking up place is Dnepropetrovsk region, 2013 and peppermint - the sample #3 (the stocking place is Lebanon, Baalbek surroundings, 2013. In order to study elemental structure of peppermint leaves, atomic emission spectrometry with photographic registration was used. Results and discussions All types of raw materials had identical element structure. According to the content in each type of raw materials, compositions can be divided into some groups: the first one – the content of element was near or above 1000 mg /100 g, the content was higher than 100 mg /100 g, the content of composition was lower than 100 mg /100 g and below than 1 mg /100 g. Thus, the ambit between these groups was deeply emphasized. The following

  14. Surface and elemental alterations of dental alloys induced by electro discharge machining (EDM).

    Science.gov (United States)

    Zinelis, Spiros

    2007-05-01

    To evaluate the surface and elemental alterations induced by electro discharge machining (EDM) on the surface of dental cast alloys used for the fabrication of implant retained meso- and super-structures. A completed cast model of an arch that received dental implants was used for the preparation of six wax patterns which were divided into three groups (Au, Co and Ti). The wax patterns of the Au and Co groups were invested with conventional phosphate-bonded silica-based investment material and the Ti group with magnesia-based investment material. The investment rings of the Au and Co groups were cast with an Au-Ag alloy (Stabilor G) and a Co-Cr base alloy (Okta C), respectively, while the investment rings of group Ti were cast with cp Ti (Biotan). One casting of each group was subjected to electro discharge machining (EDM); the other was conventionally ground and polished. The surface morphology and the elemental compositions of conventionally and EDM-finished surfaces were studied by SEM/X-ray EDS analysis. Six spectra were collected from each surface employing the area scan mode and the mean value of each element between conventionally and EDM-finished surfaces was statistically analyzed by t-test (a=0.05). Then the specimens of each group were cut perpendicular to their longitudinal axis and after metallographic grinding and polishing the cross-sections studied under the SEM. The EDM surfaces showed a significant increase in C due to the decomposition of the dielectric fluid during spark erosion. Moreover, a significant Cu uptake was noted on these surfaces from the decomposition of the Cu electrodes used for EDM. Cross-sectional analysis showed that all alloys developed a superficial zone (recast layer) varying from 2 microm for Au-Ag to 10 microm for Co-Cr alloy. The elemental composition of dental alloy surfaces is significantly altered after EDM treatment.

  15. Elemental compositions of lichens from Duolun County, Inner Mongolia, China: Origin, road effect and species difference.

    Science.gov (United States)

    Liu, Hua-Jie; Wang, Jing-Gong; Xia, Yu; Yang, Meng-Jie; Liu, Si-Wa; Zhao, Liang-Cheng; Guo, Xiu-Ping; Jiang, Yun-Jun; Li, Xin; Wu, Qing-Feng; Fang, Shi-Bo

    2017-07-17

    To assess the response of lichen elemental compositions to road traffic and species difference in the context of high dust input and anthropogenic emissions, two foliose epiphytic lichens (Phaeophyscia hirtuosa, PHh; Candelaria fibrosa, CAf) were sampled near a road adjacent to Dolon Nor Town (Duolun County, Inner Mongolia, China). Twenty elements (Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Sr, Ti, V and Zn) in lichen and surface soil samples were analysed using inductively coupled plasma mass spectrometer (ICP-MS). The results demonstrate that lichen elemental compositions are highly influenced by both their natural environment and anthropogenic input. Windblown dust associated with sand dunes and degraded/desertified steppes represents the predominant source of lichen elements. Road traffic can enhance the lichen elemental burden by increasing the number of soil particles. Anthropogenic emissions from the town and road traffic have also led to the enrichment of Cd and Zn in lichens. PHh was higher than CAf in concentrations of 14 terrigenous metals. Both lichens are applicable to biomonitoring of atmospheric element deposition and, in most cases, yield comparable results.

  16. Effect of Lamina Thickness of Prepreg on the Surface Accuracy of Carbon Fiber Composite Space Mirrors

    Science.gov (United States)

    Yang, Zhiyong; Tang, Zhanwen; Xie, Yongjie; Shi, Hanqiao; Zhang, Boming; Guo, Hongjun

    2018-02-01

    Composite space mirror can completely replicate the high-precision surface of mould by replication process, but the actual surface accuracy of the replication composite mirror always decreases. Lamina thickness of prepreg affects the layers and layup sequence of composite space mirror, and which would affect surface accuracy of space mirror. In our research, two groups of contrasting cases through finite element analyses (FEA) and comparative experiments were studied; the effect of different lamina thicknesses of prepreg and corresponding lay-up sequences was focused as well. We describe a special analysis model, validated process and result analysis. The simulated and measured surface figures both get the same conclusion. Reducing lamina thickness of prepreg used in replicating composite space mirror is propitious to optimal design of layup sequence for fabricating composite mirror, and could improve its surface accuracy.

  17. Surface contamination effects on leaf chemical composition in the Atlantic Forest

    International Nuclear Information System (INIS)

    Ferrari, A.A.; Franca, E.J.; Fernandes, E.A.N.; Bacchi, M.A.

    2006-01-01

    The exogenous material that adheres to the leaf surface affects the elemental composition of the plant itself, thereby constituting one of the major error sources in plant analysis. The present work investigated the surface contamination of leaves from the Atlantic Forest. Instrumental neutron activation analysis (INAA) was applied to assess the efficiency of leaf EDTA-washing. Chemical element concentrations were corrected using Sc (soil tracer) since resuspended soil is the main source of contamination in leaves. As a result, EDTA-washing should be used mainly for the evaluation of terrigenous elements, while the Sc-corrected concentrations are considered satisfactory for the other elements. (author)

  18. 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...

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

    International Nuclear Information System (INIS)

    Zhou, Z.; Zhang, K.; Xia, C.D.; Liu, M.T.; Zhu, J.J.; An, Z.; Bai, B.

    2015-01-01

    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 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

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

    International Nuclear Information System (INIS)

    Kozak, Vladislav; Chlup, Zdenek

    2010-01-01

    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.

  1. Surface energy and work function of elemental metals

    DEFF Research Database (Denmark)

    Skriver, Hans Lomholt; Rosengaard, N. M.

    1992-01-01

    and noble metals, as derived from the surface tension of liquid metals. In addition, they give work functions which agree with the limited experimental data obtained from single crystals to within 15%, and explain the smooth behavior of the experimental work functions of polycrystalline samples......We have performed an ab initio study of the surface energy and the work function for six close-packed surfaces of 40 elemental metals by means of a Green’s-function technique, based on the linear-muffin-tin-orbitals method within the tight-binding and atomic-sphere approximations. The results...... are in excellent agreement with a recent full-potential, all-electron, slab-supercell calculation of surface energies and work functions for the 4d metals. The present calculations explain the trend exhibited by the surface energies of the alkali, alkaline earth, divalent rare-earth, 3d, 4d, and 5d transition...

  2. Evaluation of elemental composition of clays from Campos Gerais (MG)

    International Nuclear Information System (INIS)

    Martins, Joao P.M.; Maduar, Marcelo F.; Silva, Paulo S.C da

    2013-01-01

    There are numerous applications given to clays including oil and water adsorbent, ceramic, whitening of beverages, porcelain, waste treatment, organic carrier molecules in cosmetics and pharmaceuticals, support for catalysts. In the pharmaceutical industry, the clays are used as excipients, diluents, desiccants, emulsifiers, to mask undesirable flavors, isotonic agent such as charger and delivery of active substances. These characteristics have contributed to the expansion of the search for applications of clay minerals in the cosmetic industry. The aim of this study was to determine the elemental composition of clays from Campos Gerais, Minas Gerais, with a view to their applicability in the production of cosmetics. The elements As, Ba, Br, Ce, Cl, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th,U, Yb and Zn were determined by neutron activation analysis and radionuclide activity concentration of 226 Ra, 228 Ra, 210 Pb and 40 K were determined by gamma spectrometry. It was verified that the activity concentration of radionuclides was in the same concentration as the global average, indicating that these samples do not present a risk of increased radiation exposure. The concentration of most elements determined is less than or equal to the overall mean concentrations, indicated by the values of Continental Upper Crust. (author)

  3. Toxic element composition of multani mitti clay for nutritional safety

    International Nuclear Information System (INIS)

    Waheed, S.; Faiz, Y.; Rahman, S.; Siddique, N.

    2013-01-01

    Geophagy of multani mitti (MM) clay is very common in central Pakistan especially amongst women. It was therefore mandatory to establish baseline levels of toxic elements in this clay for its safe dietary consumption by consumers of different genders, age groups and physical states. Instrumental neutron activation analysis and atomic absorption spectrometry techniques were used to determine the nutritional safety of MM clay for oral intake. All quantified toxic elements were detected at trace levels with composition in the descending order; Pb > Br > As > Sb > Hg > Cd. Comparison of these elements in MM clay with other clays shows that As, Cd, and Pb, are lowest in MM clay while its Br and Hg contents are high. Highest weekly dietary intakes of As, Br, Cd, Hg, and Sb were found to be 18, 0.05, 1.6, 9.2 and 1.1 % of the respective recommended provisional tolerable weekly intakes. The findings of this study show that As, Br, Cd, Hg and Sb in MM clay are well below the tolerance levels. However its Pb concentration is very high and may pose health concerns. The data presented in this study can be used as national base level guideline for geophagy of MM clay by men, women (normal, pregnant and lactating) and children. (author)

  4. Elemental composition of betel nut and associated chewing materials

    International Nuclear Information System (INIS)

    Ridge, C.; Akanle, O.; Spyrou, N.M.

    2001-01-01

    Betel nut chewing (Area catechu), Whether plain or wrapped inside a betel leaf 'quid' together with other substances including tobacco, has been reported as a cause of the high incidence of oral and oesophageal cancers in Asian communities worldwide. Chewing of such substances results in the formation of nitrosamines, some of which may be diabetogenic to man. The incidence of Type 2 diabetes is particularly prevalent amongst Asian immigrants living in the UK and as part of a larger study we have analysed a number of popular betel nut based chewing materials to determine their elemental composition. Instrumental neutron activation analysis was used for determination of elemental concentrations of short-lived radionuclides. Ag, Al. Br, Ca, Cl, Cu, Dy, K, Mg, Mn, Na, Ti, and V were detected, some of which are implicated in diabetes. Concentrations of these, expect for Ag, Dy and Ti, are reported and compared with values found in betel-nut and chewing materials from Taiwan. It is indicated that for certain elements the amount ingested by betel-nut chewers may be a significant fraction of their daily dietary intake. (author)

  5. Trace element composition in sediments of the Amazonian Lake Cristalino

    International Nuclear Information System (INIS)

    Ferraz, E.S.B.; Fernandes, E.A.N.

    1995-01-01

    Lake Cristalino is a small lake adjacent to the Negro River near Manaus and not far from the Amazonas River, in the central Amazon basin. The lake is fed seasonally by waters of the Negro River, a blackwater river with low levels of nutrients and suspended solids (7 g m -3 ). However, some investigations have established that Lake Cristalino has a high sedimentation rate (0.4-0.5 cm year -l ) similar to those in the alluvial floodplain lakes of the Amazonas River (suspended solids 200-300 g m -3 ). Sediment cores were taken during the low-water period and the trace-element composition and the natural radioactivity in the lake were examined. The results show a core (31 cm length) relatively uniform in concentrations of trace elements (Br, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Sc, Sm, Ta, Tb, Th, Yb and Zn), and the presence of 137 Cs in the first half. Concentrations of trace elements in Lake Cristalino sediments were not correlated with concentrations in the sediments of its parent river, the Negro River, or with concentrations in soils of the local area. However, significant correlation was found between the sediments of the lake and those of the Amazonas River. On the basis of these results, and water-level data at Manaus port, it is concluded that the lake occasionally receives variable amounts of sediment from the Amazonas River. 10 refs., 2 tabs., 2 figs

  6. Finite element analysis of composite concrete-timber beams

    Directory of Open Access Journals (Sweden)

    N. C. S. FORTI

    Full Text Available AbstractIn the search for sustainable construction, timber construction is gaining in popularity around the world. Sustainably harvested wood stores carbon dioxide, while reforestation absorbs yet more CO2. One technique involves the combination of a concrete slab and a timber beam, where the two materials are assembled by the use of flexible connectors. Composite structures provide reduced costs, environmental benefits, a better acoustic performance, when compared to timber structures, and maintain structural safety. Composite structures combine materials with different mechanical properties. Their mechanical performance depends on the efficiency of the connection, which is designed to transmit shear longitudinal forces between the two materials and to prevent vertical detachment. This study contributes with the implementation of a finite element formulation for stress and displacement determination of composite concrete-timber beams. The deduced stiffness matrix and load vector are presented along to numerical examples. Numerical examples are compared to the analytical equations available in Eurocode 5 and to experimental data found in the literature.

  7. Neural network applied to elemental archaeological Marajoara ceramic compositions

    International Nuclear Information System (INIS)

    Toyota, Rosimeiri G.; Munita, Casimiro S.; Boscarioli, Clodis

    2009-01-01

    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. 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)

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

    International Nuclear Information System (INIS)

    Santos, Eliane C.; Saiki, Mitiko

    2015-01-01

    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)

  10. Multiscale Finite Element Methods for Flows on Rough Surfaces

    KAUST Repository

    Efendiev, Yalchin

    2013-01-01

    In this paper, we present the Multiscale Finite Element Method (MsFEM) for problems on rough heterogeneous surfaces. We consider the diffusion equation on oscillatory surfaces. Our objective is to represent small-scale features of the solution via multiscale basis functions described on a coarse grid. This problem arises in many applications where processes occur on surfaces or thin layers. We present a unified multiscale finite element framework that entails the use of transformations that map the reference surface to the deformed surface. The main ingredients of MsFEM are (1) the construction of multiscale basis functions and (2) a global coupling of these basis functions. For the construction of multiscale basis functions, our approach uses the transformation of the reference surface to a deformed surface. On the deformed surface, multiscale basis functions are defined where reduced (1D) problems are solved along the edges of coarse-grid blocks to calculate nodalmultiscale basis functions. Furthermore, these basis functions are transformed back to the reference configuration. We discuss the use of appropriate transformation operators that improve the accuracy of the method. The method has an optimal convergence if the transformed surface is smooth and the image of the coarse partition in the reference configuration forms a quasiuniform partition. In this paper, we consider such transformations based on harmonic coordinates (following H. Owhadi and L. Zhang [Comm. Pure and Applied Math., LX(2007), pp. 675-723]) and discuss gridding issues in the reference configuration. Numerical results are presented where we compare the MsFEM when two types of deformations are used formultiscale basis construction. The first deformation employs local information and the second deformation employs a global information. Our numerical results showthat one can improve the accuracy of the simulations when a global information is used. © 2013 Global-Science Press.

  11. Elemental composition of cosmic rays using a maximum likelihood method

    International Nuclear Information System (INIS)

    Ruddick, K.

    1996-01-01

    We present a progress report on our attempts to determine the composition of cosmic rays in the knee region of the energy spectrum. We have used three different devices to measure properties of the extensive air showers produced by primary cosmic rays: the Soudan 2 underground detector measures the muon flux deep underground, a proportional tube array samples shower density at the surface of the earth, and a Cherenkov array observes light produced high in the atmosphere. We have begun maximum likelihood fits to these measurements with the hope of determining the nuclear mass number A on an event by event basis. (orig.)

  12. Finite Element Analysis of Composite Aircraft Fuselage Frame

    Science.gov (United States)

    Dandekar, Aditya Milind

    Composites have been introduced in aircraft industries, for their stronger, stiffer, and lighter properties than their metal-alloys counterparts. The general purpose of an aircraft is to transport commercial or military payload. Aircraft frames primarily maintains the shape of fuselage and prevent instability of the structure. Fuselage is similar as wing in construction which consist of longitudinal elements (longerons and stringers), transverse elements (frames and bulkheads) and its external skin. The fuselage is subjected to forces such as the wing reactions, landing gear reaction, empennage reaction, inertia forces subjected due to size and weight, internal pressure forces due to high altitude. Frames also ensure fail-safe design against skin crack propagation due to hoops stress. Ideal fuselage frames cross section is often circular ring shape with a frame cap of Z section. They are mainly made up of light alloy commonly used is aluminium alloys such as Al-2024, Al-7010, Al-7050, Al-7175. Aluminium alloys have good strength to density ratios in compression and bending of thin plate. A high strength to weight ratio of composite materials can result in a lighter aircraft structure or better safety factor. This research focuses on analysis of fuselage frame under dynamic load condition with change in material. Composites like carbon fibre reinforced plastics [CFRP] and glass fibre reinforced plastics [GFRP] are compared with traditional aluminium alloy Al-7075. The frame is subjected to impact test by dropping it at a velocity of 30 ft. / secs from a height of 86 inch from its centre of gravity. These parameters are considered in event of failure of landing gear, and an aircraft is subject to belly landing or gear-up landing. The shear flow is calculated due to impact force which acts in radial direction. The frame is analysed under static structural and explicit dynamic load conditions. Geometry is created in ANSYS Design Modeler. Analysis setup is created using

  13. Trace element composition and distribution in micron area of dinosaur eggshell fossils determined by proton microprobe

    International Nuclear Information System (INIS)

    Chen Youhong; Zhu Jieqing; Wang Xiaohong; Wang Yimin

    1997-01-01

    The scanning proton microprobe and micro-PIXE quantitative analysis technique have been used to determine composition and distribution of the trace elements in micron areas of dinosaur eggshell fossils from the stratum of Upper Cretaceous system at Nanxiong Basin in Guangdong Province, China. The study shows that the trace elements mainly include Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Sb, Ba and Pb in the micron area, but they present different distributions. While the element Sr is mainly enriched in the near surface layer, others mainly reside in the near inner layer. A preliminary discussion on the reason of the dinosaur extinction is given based on the above study

  14. Trace element composition and distribution in micron area of dinosaur eggshell fossils determined by proton microprobe

    International Nuclear Information System (INIS)

    Chen Youhong; Zhu Jieqing; Wang Xiaohong; Wang Yimin

    1997-01-01

    The scanning proton microprobe and micro-PIXE quantitative analysis technique have been used to determine composition and distribution of the trace elements in micron areas of dinosaur eggshell fossils from the stratum of Upper Cretaceous system at Nanxiong Basin in Guangdong Province, China. The study shows that the trace elements mainly include Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Rb, Sr, Y, Zr, Sb, Ba and Pb in the micron area, but they present different distributions. While the elements Sr is mainly enriched in the near surface layer, others mainly reside in the near inner layer. A preliminary discussion on the reason of the dinosaur extinction is given based on the above study

  15. Mineral elements in dental composites by atomic and nuclear analytical methods. II. Improved analysis by PIXE

    International Nuclear Information System (INIS)

    Preoteasa, E.A.; Ciortea, C.; Fluerasu, D.; Enescu, S.E.; Preoteasa, Elena

    2000-01-01

    In the corrosive environment of the mouth, a diversity of interactions take place at the solid-solid and solid-liquid interfaces of a tooth's filling. Moreover, the mineral elements of the restorative material may induce a complex response of the organism. The approach of these problems requires sensitive surface elemental analysis of the composite and of the dental enamel and dentine. Particle-induced X-ray emission (PIXE) is such a method and has been applied in investigations of hard dental tissues; however, it was not used so far in the study of dental composites. We continue our study by evaluating the potential of PIXE for analysis of these materials. Three types of composites with two color shades each have been studied. The measurements were performed with 3 MeV protons, using a hyperpure Ge detector in a spectroscopic chain connected to a computer. The spectra were processed with the dedicated program Leone. PIXE without additional Al absorbent foil allowed the detection of Z > 14 elements in composites. In two glass- and ceramics-based materials we found: Ca, Zr, Ba, Yb and traces of Sr and In in Tetric Ceram (Vivadent); and Ca, Zr, Ba, Hf, possibly Mn, and traces of Ni, Ho, Ti, Fe, Cr in Valux Plus (3M Dental), after elimination of the escape peaks. In quartz-based Evicrol (Spofa), Si, Ca, Ti, Fe and traces of K, Cr, Ni, Cu, Zn were seen. Materials with different color shades showed variations of Ti, Cr, Fe, Ni and Cu in Evicrol, as contrasted to Tetric Ceram and Valux Plus whose spectra were color-invariant. By its sensitivity and low background, PIXE enables the detection of many trace elements in dental composites; it could serve also in new materials' development and forensic expertise. (authors)

  16. Improvement of Reactor Fuel Element Heat Transfer by Surface Roughness

    International Nuclear Information System (INIS)

    Kjellstroem, B.; Larsson, A.E.

    1967-04-01

    In heat exchangers with a limited surface temperature such as reactor fuel elements, rough heat transfer surfaces may give lower pumping power than smooth. To obtain data for choice of the most advantageous roughness for the superheater elements in the Marviken reactor, measurements were made of heat transfer and pressure drop in an annular channel with a smooth or rough test rod in a smooth adiabatic shroud. 24 different roughness geometries were tested. The results were transformed to rod cluster geometry by the method of W B Hall, and correlated by the friction and heat transfer similarity laws as suggested by D F Dipprey and R H Sabersky with RMS errors of 12.5 % in the friction factor and 8.1 % in the Stanton number. The relation between the Stanton number and the friction factor could be described by a relation of the type suggested by W Nunner, with a mean error of 3.1 % and an RMS error of 11.6 %. Application of the results to fuel element calculations is discussed, and the great gains in economy which can be obtained with rough surfaces are demonstrated by two examples

  17. Improvement of Reactor Fuel Element Heat Transfer by Surface Roughness

    Energy Technology Data Exchange (ETDEWEB)

    Kjellstroem, B; Larsson, A E

    1967-04-15

    In heat exchangers with a limited surface temperature such as reactor fuel elements, rough heat transfer surfaces may give lower pumping power than smooth. To obtain data for choice of the most advantageous roughness for the superheater elements in the Marviken reactor, measurements were made of heat transfer and pressure drop in an annular channel with a smooth or rough test rod in a smooth adiabatic shroud. 24 different roughness geometries were tested. The results were transformed to rod cluster geometry by the method of W B Hall, and correlated by the friction and heat transfer similarity laws as suggested by D F Dipprey and R H Sabersky with RMS errors of 12.5 % in the friction factor and 8.1 % in the Stanton number. The relation between the Stanton number and the friction factor could be described by a relation of the type suggested by W Nunner, with a mean error of 3.1 % and an RMS error of 11.6 %. Application of the results to fuel element calculations is discussed, and the great gains in economy which can be obtained with rough surfaces are demonstrated by two examples.

  18. Finite element based composite solution for neutron transport problems

    International Nuclear Information System (INIS)

    Mirza, A.N.; Mirza, N.M.

    1995-01-01

    A finite element treatment for solving neutron transport problems is presented. The employs region-wise discontinuous finite elements for the spatial representation of the neutron angular flux, while spherical harmonics are used for directional dependence. Composite solutions has been obtained by using different orders of angular approximations in different parts of a system. The method has been successfully implemented for one dimensional slab and two dimensional rectangular geometry problems. An overall reduction in the number of nodal coefficients (more than 60% in some cases as compared to conventional schemes) has been achieved without loss of accuracy with better utilization of computational resources. The method also provides an efficient way of handling physically difficult situations such as treatment of voids in duct problems and sharply changing angular flux. It is observed that a great wealth of information about the spatial and directional dependence of the angular flux is obtained much more quickly as compared to Monte Carlo method, where most of the information in restricted to the locality of immediate interest. (author)

  19. FEATURES OF ELEMENTAL COMPOSITION IN SCHOOLCHILD WITH ASCARIASIS

    Directory of Open Access Journals (Sweden)

    I. A. Lokhmatova

    2018-01-01

    Full Text Available Objective: to study the features of elemental composition in schoolchildren with ascariasis and to compare the revealed features with clinical manifestations of invasion.Materials and methods: 43 children (7 — 18 years with ascariasis (diagnostics was carried out by the method of thick smear according to Kato two times with an interval of 3 days and the method of flotation according to Kalantaryan: I subgroup — children of primary school age — 15 people, II subgroup — children of senior school age — 28 people. The control group was 32 relatively healthy schoolchildren. It was determined of 19 chemical elements (Ca, Zn, K, I, Cu, Se, Fe, Mn, Cr, S, Br, Cl, Co, Ni, Mo, Sr, Ba, Pb, Cd in children's hair was determined.Results: Low content of Zn, Cu, I, Se, Fe and Se, Br, Co, Ni, as well as increase of toxic Pb and Cd in the hair of junior schoolchildren with ascariasis is established. The invaders of high school students have a significantly lowered level of Ca, Zn, Cu, Fe and Br, Ni, Mo, as well as an elevated level of Ba, Pb, Cd.Conclusions: Imbalance of micro- and macroelements in the intestinal stage of ascariasis in children is an important pathogenetic link in the formation of the main clinical syndromes in children. Replenishment of microelement imbalance at the stage of treatment and rehabilitation of children with ascariasis is pathogenetically grounded and promotes the speedy restoration of all disturbed functions of the macroorganism. 

  20. X ray microanalysis of leaf and seed elemental composition among four species of living fossil gymnosperm

    International Nuclear Information System (INIS)

    Chang Chongyan; Li Yongliang; Chen Xiaoduan; Liu Jinying; Zhou Yunlong

    2002-01-01

    The leaf and seed elemental composition and average mass fraction are analysed or four species of living fossil gymnosperm: Ginkgo biloba L., Cathaya argyrophylla Chun et Kuang, Glyptostrobus pensilis (D. Don) Koch and Metasequoia glyptostroboides Hu et Cheng by SEM X ray microanalysis method. The results show that the elemental composition is different and the elemental average mass fraction is evidently different between the seed and leaf for the same species. The elemental composition and average mass fraction between seed and seed wing is different in Cathaya argyrophylla and Metasequoia glyptostroboides. Among three type leaf of Glyptostrobus pensilis, the elemental composition is the same, but average mass fraction is very different

  1. Solving the incompressible surface Navier-Stokes equation by surface finite elements

    Science.gov (United States)

    Reuther, Sebastian; Voigt, Axel

    2018-01-01

    We consider a numerical approach for the incompressible surface Navier-Stokes equation on surfaces with arbitrary genus g (S ) . The approach is based on a reformulation of the equation in Cartesian coordinates of the embedding R3, penalization of the normal component, a Chorin projection method, and discretization in space by surface finite elements for each component. The approach thus requires only standard ingredients which most finite element implementations can offer. We compare computational results with discrete exterior calculus simulations on a torus and demonstrate the interplay of the flow field with the topology by showing realizations of the Poincaré-Hopf theorem on n-tori.

  2. Surface photovoltage measurements and finite element modeling of SAW devices.

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, Christine

    2012-03-01

    Over the course of a Summer 2011 internship with the MEMS department of Sandia National Laboratories, work was completed on two major projects. The first and main project of the summer involved taking surface photovoltage measurements for silicon samples, and using these measurements to determine surface recombination velocities and minority carrier diffusion lengths of the materials. The SPV method was used to fill gaps in the knowledge of material parameters that had not been determined successfully by other characterization methods. The second project involved creating a 2D finite element model of a surface acoustic wave device. A basic form of the model with the expected impedance response curve was completed, and the model is ready to be further developed for analysis of MEMS photonic resonator devices.

  3. An Axial Sliding Test for machine elements surfaces

    DEFF Research Database (Denmark)

    Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

    2012-01-01

    are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional and a fine......Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder...... liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve...

  4. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE-RBS

    Science.gov (United States)

    Zhou, Z.; Zhang, K.; Xia, C. D.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.

    2015-03-01

    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 LaB6 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 propagated to the Waguantan kiln site of Guizhou Province in the Yuan Dynasty.

  5. Brazed graphite/refractory metal composites for first-wall protection elements

    Science.gov (United States)

    Šmid, I.; Croessmann, C. D.; Salmonson, J. C.; Whitley, J. B.; Kny, E.; Reheis, N.; Kneringer, G.; Nickel, H.

    1991-03-01

    The peak surface heat flux deposition on divertor elements of near term fusion devices is expected to exceed 10 MW/m 2. The needed reliability of brazed plasma interactive components, particularly under abnormal operating conditions with peak surface temperatures well beyond 1000°C, makes refractory metallic substrates and brazes with a high melting point very attractive. TZM, a high temperature alloy of molybdenum, and isotropic graphite, materials very closely matched in their thermal expansion, were brazed with four high-temperature brazes. The brazes used were Zr, 90Ni/10Ti, 90Cu/10Ti and 70Ag/27Cu/3Ti (nominal composition prior to brazing, wt%). The resulting composite tiles of 50 × 50 mm2 with a TZM thickness of 5 mm and a graphite thickness of 10 mm have been tested in high heat flux simulation for their thermal fatigue properties. Up to 600 loading cycles were carried out with an average heat flux of 10 MW/m 2 for 0.5 s pulses. The maximum surface temperature was 1100°C. In support of the experiment, the thermal response and temperature gradients of the samples were investigated using a finite element model.

  6. Brazed graphite/refractory metal composites for first-wall protection elements

    International Nuclear Information System (INIS)

    Smid, I.; Croessmann, C.D.; Salmonson, J.C.; Whitley, J.B.; Nickel, H.

    1991-01-01

    The peak surface heat flux deposition on divertor elements of near term fusion devices is expected to exceed 10 MW/m 2 . The needed reliability of brazed plasma interactive components, particularly under abnormal operating conditions with peak surface temperatures well beyond 1000deg C, makes refractory metallic substrates and brazes with a high melting point very attractive. TZM, a high temperature alloy of molybdenum, and isotropic graphite, materials very closely matched in their thermal expansion, were brazed with four high-temperature brazes. The brazes used were Zr, 90Ni/10Ti, 90Cu/10Ti and 70Ag/27Cu/3Ti (nominal composition prior to brazing, wt%). The resulting composite tiles of 50x50 mm 2 with a TZM thickness of 5 mm and a graphite thickness of 10 mm have been tested in high heat flux simulation for their thermal fatigue properties. Up to 600 loading cycles were carried out with an average heat flux of 10 MW/m 2 for 0.5 s pulses. The maximum surface temperature was 1100deg C. In support of the experiment, the thermal response and temperature gradients of the samples were investigated using a finite element model. (orig.)

  7. Brazed graphite/refractory metal composites for first-wall protection elements

    International Nuclear Information System (INIS)

    Smid, I.; Croessmann, C. D.; Salmonson, J. C.; Whitley, J. B.; Kny, E.; Reheis, N.; Kneringer, G.; Nickel, H.

    1995-01-01

    The peak surface heat flux deposition on divertor elements of near term fusion devices is expected to exceed 10 MW/m 2 . The needed reliability of brazed plasma interactive components, particularly under abnormal operating conditions with peak surface temperatures well beyond 1000 degree C, makes refractory metallic substrates and brazes with a high melting point very attractive. TZM, a high temperature alloy of molybdenum, and isotropic graphite, materials very closely matched in their thermal expansion, were brazed with four high-temperature brazes. The brazes used were Zr, 90Ni/10Ti, 90Cu/10Ti and 70Ag/27Cu/3Ti (nominal composition prior to brazing, wt%). The resulting composite tiles of 5O X 50 mm 2 with a TZM thickness of 5 mm and a graphite thickness of 10 mm have been tested in high heat flux simulation for their thermal fatigue properties. Up to 600 loading cycles were carried out with an average heat flux of 10 MW/m 2 for 0.5 s pulses. The maximum surface temperature was 1100 degree C. In support of the experiment, the thermal response and temperature gradients of the samples were investigated using a finite element model. (author)

  8. 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

  9. Surface tension of compositions of polyhexametyleneguanidine hydrochloride - surfactants

    Directory of Open Access Journals (Sweden)

    S. Kumargaliyeva

    2012-12-01

    Full Text Available We made up songs bactericidal polyhexamethyleneguanidine hydrochloride (metacyde with the surface-active substances - anionic sodium dodecylsulfate, cationic cetylpyridinium bromide, and nonionic Tween-80 and measured the surface tension of water solutions. The study showed that the composition metacyde with surface-active agents have a greater surface activity than the individual components.

  10. Investigation of chemical forms of elements in surface waters

    International Nuclear Information System (INIS)

    Varshal, G.M.; Velyukhanova, T.K.; Koshcheeva, I.Ya.; Dorofeeva, V.A.; Buachidze, N.S.; Kasimova, O.G.; Makharadze, G.A.

    1983-01-01

    The main trends in the research of the state of elements in natural waters are examined. The hydrolysis of CU(2), Hg(2), Au(3), Sb(3), Ru(4) over a pH range, specific for natural waters, has been studied by solubility and paper electrophoresis technnques and by filtration through cellulose ionites. The regions of predominating different forms of hydroxo complexes have been found and the thermodynamic constants of hydrolysis equilibria have been calculated. Solubility, filtration through sephadexes and cellulose ionites, paper electrophoresis techniques were used to study the complexation of Cu(2), Hg(2), Au(3), Sb(3), Ru(4) with fulvic acids. Some data have been obtained on the composition, stability and molecular-mass distribution of fulvate complexes of ten elements in different oxidation states. High-molecular anionic fulvate complexes are among main forms of most easily hydrolysed elments in solution. The possibility has been shown of prediction of the ratio of coexisting forms of trace elements in solution by theoretical calculations and experimentally Using fractionation on cellulose ionites and sephadexes

  11. Surface roughness of etched composite resin in light of composite repair

    NARCIS (Netherlands)

    Loomans, B.A.C.; Cardoso, M.V.; Opdam, N.J.M.; Roeters, F.J.M.; Munck, J. De; Huysmans, M.C.D.N.J.M.; Meerbeek, B. Van

    2011-01-01

    OBJECTIVES: In search for clinically effective composite repair protocols, the effect of various etching protocols on the surface roughness of composite resins with different filler composition were investigated. METHODS: Of two composite resins (hybrid-filled Clearfil AP-X; nano-filled Filtek

  12. Controlled Dissolution of Surface Layers for Elemental Analysis by Inductively Coupled Plasma-Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Lorge, Susan Elizabeth [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Determining the composition of thin layers is increasingly important for a variety of industrial materials such as adhesives, coatings and microelectronics. Secondary ion mass spectrometry (SIMS), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), glow discharge optical emission spectroscopy (GDOES), glow discharge mass spectrometry (GDMS), and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are some of the techniques that are currently employed for the direct analysis of the sample surface. Although these techniques do not suffer from the contamination problems that often plague sample dissolution studies, they do require matrix matched standards for quantification. Often, these standards are not readily available. Despite the costs of clean hoods, Teflon pipette tips and bottles, and pure acids, partial sample dissolution is the primary method used in the semiconductor industry to quantify surface impurities. Specifically, vapor phase decomposition (VPD) coupled to ICP-MS or total reflection x-ray fluorescence (TXRF) provides elemental information from the top most surface layers at detection sensitivities in the 107-1010atoms/cm2 range. The ability to quantify with standard solutions is a main advantage of these techniques. Li and Houk applied a VPD-like technique to steel. The signal ratio of trace element to matrix element was used for quantification. Although controlled dissolution concentrations determined for some of the dissolved elements agreed with the certified values, concentrations determined for refractory elements (Ti, Nb and Ta) were too low. LA-ICP-MS and scanning electron microscopy (SEM) measurements indicated that carbide grains distributed throughout the matrix were high in these refractory elements. These elements dissolved at a slower rate than the matrix element, Fe. If the analyte element is not removed at a rate similar to the matrix element a true

  13. Glass fibres reinforced polyester composites degradation monitoring by surface analysis

    Energy Technology Data Exchange (ETDEWEB)

    Croitoru, Catalin [“Transilvania” University of Brasov, Materials Engineering and Welding Department, Eroilor 29 Str., 500036 Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design Environment and Mechatronics Department, Eroilor 29 Str., 500036 Brasov (Romania); Papancea, Adina [“Transilvania” University of Brasov, Product Design Environment and Mechatronics Department, Eroilor 29 Str., 500036 Brasov (Romania); Baltes, Liana; Tierean, Mircea [“Transilvania” University of Brasov, Materials Engineering and Welding Department, Eroilor 29 Str., 500036 Brasov (Romania)

    2015-12-15

    Highlights: • Glass fibre-reinforced polyester composites surface analysis by photographic method. • The composites are submitted to accelerated ageing by UV irradiation at 254 nm. • The UV irradiation promotes differences in the surface chemistry of the composites. • MB dye is differently adsorbed on surfaces with different degradation degrees. • Good correlation between the colouring degree and surface chemistry. - Abstract: The paper presents a novel method for quantification of the modifications that occur on the surface of different types of gel-coated glass fibre-reinforced polyester composites under artificial UV-ageing at 254 nm. The method implies the adsorption of an ionic dye, namely methylene blue, on the UV-aged composite, and computing the CIELab colour space parameters from the photographic image of the coloured composite's surface. The method significantly enhances the colour differences between the irradiated composites and the reference, in contrast with the non-coloured ones. The colour modifications that occur represent a good indicative of the surface degradation, alteration of surface hydrophily and roughness of the composite and are in good correlation with the ATR-FTIR spectroscopy and optical microscopy results. The proposed method is easier, faster and cheaper than the traditional ones.

  14. Surface charge method for molecular surfaces with curved areal elements I. Spherical triangles

    Science.gov (United States)

    Yu, Yi-Kuo

    2018-03-01

    Parametrizing a curved surface with flat triangles in electrostatics problems creates a diverging electric field. One way to avoid this is to have curved areal elements. However, charge density integration over curved patches appears difficult. This paper, dealing with spherical triangles, is the first in a series aiming to solve this problem. Here, we lay the ground work for employing curved patches for applying the surface charge method to electrostatics. We show analytically how one may control the accuracy by expanding in powers of the the arc length (multiplied by the curvature). To accommodate not extremely small curved areal elements, we have provided enough details to include higher order corrections that are needed for better accuracy when slightly larger surface elements are used.

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

    Science.gov (United States)

    Lou, Leo; Nelson, Alan E.; Heo, Giseon; Major, Paul W.

    2008-08-01

    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.

  16. 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.

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

    International Nuclear Information System (INIS)

    Lou, Leo; Nelson, Alan E.; Heo, Giseon; Major, Paul W.

    2008-01-01

    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

  18. Ion beam effects on the surface and near-surface composition of TaSi2

    International Nuclear Information System (INIS)

    Valeri, S.; Di Bona, A.; Ottaviani, G.; Procop, M.

    1991-01-01

    Low-energy (0.7-4.5 keV) ion bombardment effects on polycrystalline TaSi 2 at sputter steady state and in various intermediate steps have been investigated, in the temperature range up to 550degC, to determine the time and temperature dependence of the altered layer formation. This in turn enables a better knowledge of the synergistic effects of the processes mentioned above. At low temperatures (T≤410degC) the surface is silicon depleted, and the depletion is even more severe in the subsurface region up to a depth of several tens of angstroems; silicon preferential sputtering and radiation-enhanced segregation assisted by the displacement mixing-induced motion of atoms are assumed to be responsible for this composition profile, while thermally activated diffusion processes become operative above 410degC, reducing progressively the concentration gradient between the surface and the subsurface zone. The composition at different depths has been determined from Auger peaks for different kinetic energies, by varying the take-off angle and finally by sputter profiling at low in energy the high energy processed surfaces. Quantitative analysis has been performed by XPS and AES by using the elemental standard method. (orig.)

  19. Immediate repair bond strengths of microhybrid, nanohybrid and nanofilled composites after different surface treatments

    NARCIS (Netherlands)

    Rinastiti, Margareta; Siswomihardjo, Widowati; Busscher, Henk J.; Ozcan, Mutlu

    Objectives: To evaluate immediate repair bond strengths and failure types of resin composites with and without surface conditioning and characterize the interacting composite surfaces by their surface composition and roughness. Methods: Microhybrid, nanohybrid and nanofilled resin composites were

  20. 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.

  1. Bacterial Cell Surface Adsorption of Rare Earth Elements

    Science.gov (United States)

    Jiao, Y.; Park, D.; Reed, D.; Fujita, Y.; Yung, M.; Anderko, A.; Eslamimanesh, A.

    2015-12-01

    Rare earth elements (REE) play a critical role in many emerging clean energy technologies, including high-power magnets, wind turbines, solar panels, hybrid/electric vehicle batteries and lamp phosphors. In order to sustain demand for such technologies given current domestic REE shortages, there is a need to develop new approaches for ore processing/refining and recycling of REE-containing materials. To this end, we have developed a microbially-mediated bioadsorption strategy with application towards enrichment of REE from complex mixtures. Specifically, the bacterium Caulobacter crescentus was genetically engineered to display lanthanide binding tags (LBTs), short peptides that possess high affinity and specificity for rare earth elements, on its cell surface S-layer protein. Under optimal conditions, LBT-displayed cells adsorbed greater than 5-fold more REE than control cells lacking LBTs. Competition binding experiments with a selection of REEs demonstrated that our engineered cells could facilitate separation of light- from heavy- REE. Importantly, binding of REE onto our engineered strains was much more favorable compared to non-REE metals. Finally, REE bound to the cell surface could be stripped off using citrate, providing an effective and non-toxic REE recovery method. Together, this data highlights the potential of our approach for selective REE enrichment from REE containing mixtures.

  2. 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

  3. Brazed graphite/refractory metal composites for first wall protection elements

    International Nuclear Information System (INIS)

    Smid, I.; Croessmann, C. D.; Salmonson, J. C.; Whitley, J. B.; Kny, E.; Reheis, N; Kneringer, G.; Nickel, H.

    1995-01-01

    The peak surface heat flux deposition on divertor elements of near term fusion devices is expected to exceed 10 MW/m 2 . The needed reliability of brazed plasma interactive components, particularly under abnormal operating conditions with peak surface temperatures well beyond 1000 degree C, makes refractory metallic substrates and brazes with a high melting point very attractive. TZM, a high temperature alloy of molybdenum, and isotropic graphite, materials very closely matched in their thermal expansion, were brazed with four high-temperature brazes. The brazes used were Zr, 90Ni/10Ti, 90Cu/10Ti and 70Ag/27Cu/10Ti (nominal composition prior to brazing, wt%). The resulting composite tiles of 50 x 50 mm with a TZM thickness of 5 mm and a graphite thickness of 10 mm have been tested in high heat flux simulation for their thermal fatigue properties. Up to 600 loading cycles were carried out with the experimental parameters chosen to cover NET/ITER design specifications. In support of the experiment, the thermal response and temperature gradients of the samples were investigated using a finite element model. (author)

  4. Improved PIXE analysis of micro- and trace elements in dental composites

    International Nuclear Information System (INIS)

    Preoteasa, E. A.; Ciortea, C.; Fluerasu, D.; Enescu, S. E.; Preoteasa, E.

    2001-01-01

    Due to the interactions occurring at the solid-solid and solid-liquid interfaces of a tooth's filling, the mineral elements of the restorative composite may induce a complex response of the organism. To study such problems, sensitive surface trace element analysis is required. Particle-induced X-ray emission (PIXE) has a detection limit one order of magnitude lower than XRF and has been used for hard dental tissues, but not yet for dental composites. We evaluated the potential of PIXE in a study of ten types of composites used in restorative dentistry, some of them with two color shades each. The samples were prepared as described for XRF. The measurements were performed with 3 MeV protons from a van de Graaff tandem linear accelerator, using a hyper pure Ge detector and collecting the spectra for 1.5-4 hours. The spectra were processed with the program Leone. The proton route in the sample calculated with the Trim program (∼ 50-100 μm) exceeded the size of mineral particles (0.02-30 μm), thus granularity did not affect the analysis. The PIXE analysis detected Z ≥ 19 elements in all composites, and Z≥14 elements in only one low Z material. PIXE detected generally the same dominant elements, but many more trace elements than XRF. Thus both Charisma (Kulzer) and Pekafill (Bayer) contained Ba as the major element, but trace elements were Ni, Zn, In, in the first, and Fe, Cu, Zn, Sr, Ag in the second. In other glass- and ceramics-based materials we found: Ca, Zr, Ba, Yb and traces of Sr, In, and possibly Ti in Tetric Ceram and in Ariston (both from Vivadent); Ca, Zr, Ba, Hf, possibly Mn, and traces of Ni, Ho, Ti, Fe, Cr in Valux Plus (3M Dental); Sr, Ba (major), K, Fe, Mn (minor), and traces of Ni, Zn, In, in F2000 Compomer (3M Dental); Ba (major) and traces of Fe, Ni, Sr in Surefil (Dentsply). In quartz-based materials we detected: Si, Ca, Ti, Fe and traces of K, Cl, Cr, Ni, Cu, Zn in Evicrol (Spofa); low and trace levels of Ca, Ti, Cr, Mn, Fe, Cu in

  5. Relevance of leaf surface contamination for assessing chemical composition of bromeliads in a restinga forest

    Energy Technology Data Exchange (ETDEWEB)

    Elias, C; Fernandes, E A.N.; Franca, E J; Bacchi, M A; Tagliaferro, F S [Centro de Energia Nuclear na Agricultura, Universidade de Sao Paulo, Piracicaba, SP (Brazil)

    2008-11-15

    Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in nonwashed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues. (author)

  6. Relevance of leaf surface contamination for assessing chemical composition of bromeliads in a restinga forest

    International Nuclear Information System (INIS)

    Elias, C.; Fernandes, E.A.N.; Franca, E.J.; Bacchi, M.A.; Tagliaferro, F.S.

    2008-01-01

    Resuspended soil and other airborne particles adhered to the leaf surface affect the chemical composition of the plant. A well-defined cleaning procedure is necessary to avoid this problem, providing a correct assessment of the inherent chemical composition of bromeliads. To evaluate the influence of a washing procedure, INAA was applied for determining chemical elements in the leaves of bromeliads from Vriesea carinata species, both non-washed and washed with Alconox, EDTA and bi-distilled water. Br, Ce, Hg, La, Sc, Se, Sm and Th showed higher mass fractions in nonwashed leaves. The washing procedure removed the exogenous material without leaching chemical elements from inside the tissues. (author)

  7. Sputtering induced surface composition changes in copper-palladium alloys

    International Nuclear Information System (INIS)

    Sundararaman, M.; Sharma, S.K.; Kumar, L.; Krishnan, R.

    1981-01-01

    It has been observed that, in general, surface composition is different from bulk composition in multicomponent materials as a result of ion beam sputtering. This compositional difference arises from factors like preferential sputtering, radiation induced concentration gradients and the knock-in effect. In the present work, changes in the surface composition of copper-palladium alloys, brought about by argon ion sputtering, have been studied using Auger electron spectroscopy. Argon ion energy has been varied from 500 eV to 5 keV. Enrichment of palladium has been observed in the sputter-altered layer. The palladium enrichment at the surface has been found to be higher for 500 eV argon ion sputtering compared with argon ion sputtering at higher energies. Above 500 eV, the surface composition has been observed to remain the same irrespective of the sputter ion energy for each alloy composition. The bulk composition ratio of palladium to copper has been found to be linearly related to the sputter altered surface composition ratio of palladium to copper. These results are discussed on the basis of recent theories of alloy sputtering. (orig.)

  8. Surface coating Zr or Zr alloy nuclear fuel elements

    International Nuclear Information System (INIS)

    Donaghy, R.E.; Sherman, A.H.

    1980-01-01

    A method is disclosed for preventing stress corrosion cracking or metal embrittlement of a zirconium or zirconium alloy container that is to be coated on the inside surface with a layer of a metal such as copper, a copper alloy, nickel, or iron and used for holding nuclear fuel material as a nuclear fuel element. The zirconium material is etched in an etchant solution, desmutted mechanically or ultrasonically, oxidized to form an oxide coating on the zirconium, cleaned in an aqueous alkaline cleaning solution, activated for electroless deposition of a metal layer and contacted with an electroless metal plating solution. This method provides a boundary layer of zirconium oxide between the zirconium container and the metal layer. (author)

  9. Quantitative morphological and compositional evaluation of laboratory prepared aluminoborosilicate glass surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Yuxuan, E-mail: yg4@alfred.edu; Wren, Anthony W.; Mellott, Nathan P.

    2015-01-01

    -correlation model fitting of PSD profiles derived via AFM. The chemical environment of elements, as determined via XPS, present on the prepared surfaces are similar to those within the pristine bulk glass. The compositional evolution of polished and melt surfaces are discussed in context of corrosion phenomena associated with the grinding, polishing, and etching of surfaces and the thermal heat treatment utilized for processing, respectively. Good correlation between surface finishing methods, chemical composition and topographical parameters were observed. More importantly, extensive discussions on topographical parameters including equivalent RMS, Hurst exponent, and fractal dimension are presented as a function of processing method.

  10. Static and Vibrational Analysis of Partially Composite Beams Using the Weak-Form Quadrature Element Method

    Directory of Open Access Journals (Sweden)

    Zhiqiang Shen

    2012-01-01

    Full Text Available Deformation of partially composite beams under distributed loading and free vibrations of partially composite beams under various boundary conditions are examined in this paper. The weak-form quadrature element method, which is characterized by direct evaluation of the integrals involved in the variational description of a problem, is used. One quadrature element is normally sufficient for a partially composite beam regardless of the magnitude of the shear connection stiffness. The number of integration points in a quadrature element is adjustable in accordance with convergence requirement. Results are compared with those of various finite element formulations. It is shown that the weak form quadrature element solution for partially composite beams is free of slip locking, and high computational accuracy is achieved with smaller number of degrees of freedom. Besides, it is found that longitudinal inertia of motion cannot be simply neglected in assessment of dynamic behavior of partially composite beams.

  11. Nonhazardous solvent composition and method for cleaning metal surfaces

    International Nuclear Information System (INIS)

    Googin, J.M.; Simandl, R.F.; Thompson, L.M.

    1993-01-01

    A solvent composition for displacing greasy and oily contaminants as well as water and/or aqueous residue from metallic surfaces, especially surfaces of radioactive materials so that such surfaces can be wiped clean of the displaced contaminants, water and/or aqueous residue. The solvent composition consists essentially of a blend of nonpolar aliphatic hydrocarbon solvent having a minimum flash point of about 140 F and 2 to 25 volume percent of a polar solvent having a flash point sufficiently high so as to provide the solvent composition with a minimum flash point of at least 140 F. The solvent composition is nonhazardous so that when it is used to clean the surfaces of radioactive materials the waste in the form of paper or cloth wipes, lab coats and the like used in the cleaning operation is not considered to be mixed waste composed of a hazardous solvent and a radioactive material

  12. Surface composition of carburized tungsten trioxide and its catalytic activity

    International Nuclear Information System (INIS)

    Nakazawa, M.; Okamoto, H.

    1985-01-01

    The surface composition and electronic structure of carburized tungsten trioxide are investigated using x-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catalytic activity for methanol electro-oxidation is clarified. The tungsten carbide concentration in the surface layer increases with the carburization time. The formation of tungsten carbide enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity

  13. Hot Surface Ignition of A Composite Fuel Droplet

    Directory of Open Access Journals (Sweden)

    Glushkov Dmitrii O.

    2015-01-01

    Full Text Available The present study examines the characteristics of conductive heating (up to ignition temperature of a composite fuel droplet based on coal, liquid petroleum products, and water. In this paper, we have established the difference between heat transfer from a heat source to a fuel droplet in case of conductive (hot surface and convective (hot gas heat supply. The Leidenfrost effect influences on heat transfer characteristics significantly due to the gas gap between a composite fuel droplet and a hot surface.

  14. Electronic and elemental properties of the Cu2ZnSn(S,Se)4 surface and grain boundaries

    International Nuclear Information System (INIS)

    Haight, Richard; Shao, Xiaoyan; Wang, Wei; Mitzi, David B.

    2014-01-01

    X-ray and femtosecond UV photoelectron spectroscopy, secondary ion mass spectrometry and photoluminescence imaging were used to investigate the electronic and elemental properties of the CZTS,Se surface and its oxides. Oxide removal reveals a very Cu poor and Zn rich surface relative to bulk composition. O and Na are observed at the surface and throughout the bulk. Upward bending of the valence bands indicates the presence of negative charge in the surface region and the Fermi level is found near the band gap center. The presence of point defects and the impact of these findings on grain boundary properties will be described

  15. Electronic and elemental properties of the Cu2ZnSn(S,Se)4 surface and grain boundaries

    Science.gov (United States)

    Haight, Richard; Shao, Xiaoyan; Wang, Wei; Mitzi, David B.

    2014-01-01

    X-ray and femtosecond UV photoelectron spectroscopy, secondary ion mass spectrometry and photoluminescence imaging were used to investigate the electronic and elemental properties of the CZTS,Se surface and its oxides. Oxide removal reveals a very Cu poor and Zn rich surface relative to bulk composition. O and Na are observed at the surface and throughout the bulk. Upward bending of the valence bands indicates the presence of negative charge in the surface region and the Fermi level is found near the band gap center. The presence of point defects and the impact of these findings on grain boundary properties will be described.

  16. Investigating Planetesimal Evolution by Experiments with Fe-Ni Metallic Melts: Light Element Composition Effects on Trace Element Partitioning Behavior

    Science.gov (United States)

    Chabot, N. L.

    2017-12-01

    As planetesimals were heated up in the early Solar System, the formation of Fe-Ni metallic melts was a common occurrence. During planetesimal differentiation, the denser Fe-Ni metallic melts separated from the less dense silicate components, though some meteorites suggest that their parent bodies only experienced partial differentiation. If the Fe-Ni metallic melts did form a central metallic core, the core eventually crystallized to a solid, some of which we sample as iron meteorites. In all of these planetesimal evolution processes, the composition of the Fe-Ni metallic melt influenced the process and the resulting trace element chemical signatures. In particular, the metallic melt's "light element" composition, those elements present in the metallic melt in a significant concentration but with lower atomic masses than Fe, can strongly affect trace element partitioning. Experimental studies have provided critical data to determine the effects of light elements in Fe-Ni metallic melts on trace element partitioning behavior. Here I focus on combining numerous experimental results to identify trace elements that provide unique insight into constraining the light element composition of early Solar System Fe-Ni metallic melts. Experimental studies have been conducted at 1 atm in a variety of Fe-Ni systems to investigate the effects of light elements on trace element partitioning behavior. A frequent experimental examination of the effects of light elements in metallic systems involves producing run products with coexisting solid metal and liquid metal phases. Such solid-metal-liquid-metal experiments have been conducted in the Fe-Ni binary system as well as Fe-Ni systems with S, P, and C. Experiments with O-bearing or Si-bearing Fe-Ni metallic melts do not lend themselves to experiments with coexisting solid metal and liquid metal phases, due to the phase diagrams of these elements, but experiments with two immiscible Fe-Ni metallic melts have provided insight into

  17. Surface characterization of lignocellulosics for composite manufacture

    Science.gov (United States)

    Iyer, Ananth V.

    The objectives of this research were to form moisture resistant wheat strawboards, either by altering the straw surface characteristics or by changing the chemistry of the polymeric 4, 4' diphenylmethane diisocyanate (PMDI)-based matrix and interface. Part I compared the surface characteristics of wheat, barley, oat, rice, kenaf, hemp and softwood particles. All cereal straws had two surfaces: epidermis and brittle-pith unlike one heterogeneous type observed for bast fibers and softwood particles. The epidermis of cereal straws was not wet by water or aqueous binders, whereas the pith surface allowed the penetration of water, but was not readily wetted by aqueous binders. Between the different surface treatments evaluated for wheat straw in Part II, NaOH selectively peeled-off the epidermis and pith layers. The treated straw particles were formable into strawboards using aqueous phenol-formaldehyde, urea-formaldehyde, and duroplastic acrylic acid binders with good internal bond strength (IBS) and adequate water resistance. In Part III it was shown that, decreasing straw particle sizes and bleaching worsened the mechanical properties of strawboards, but the moisture absorption properties of bleached strawboards were lower than the unbleached ones. Layering of straw particles in strawboards did not seem to affect their mechanical or moisture absorption properties. Part IV showed that the pith surface of wheat straw was fractured on curing with PMDI, providing hollow microcrevices for water accumulation. Furthermore, the cured PMDI formed a network polyurea/polyuretonimine/polycarbodiimide/polyisocyanurate polymer on straw surfaces whose properties dictated the properties of strawboards. Among the different mono-, bi-, and tri-functional alcohols, amines and carboxylic acids evaluated in Part V as H-donor substitutes to moisture for reaction with PMDI on straw surfaces, ethylene glycol, resorcinol, glycerin and citric acid provided IBS values greater than the ANSI

  18. Composition and physical properties of Enceladus' surface

    Science.gov (United States)

    Brown, R.H.; Clark, R.N.; Buratti, B.J.; Cruikshank, D.P.; Barnes, J.W.; Mastrapa, R.M.E.; Bauer, J.; Newman, S.; Momary, T.; Baines, K.H.; Bellucci, G.; Capaccioni, F.; Cerroni, P.; Combes, M.; Coradini, A.; Drossart, P.; Formisano, V.; Jaumann, R.; Langavin, Y.; Matson, D.L.; McCord, T.B.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe

    2006-01-01

    Observations of Saturn's satellite Enceladus using Cassini's Visual and Infrared Mapping Spectrometer instrument were obtained during three flybys of Enceladus in 2005. Enceladus' surface is composed mostly of nearly pure water ice except near its south pole, where there are light organics, CO2, and amorphous and crystalline water ice, particularly in the region dubbed the "tiger stripes." An upper limit of 5 precipitable nanometers is derived for CO in the atmospheric column above Enceladus, and 2% for NH 3 in global surface deposits. Upper limits of 140 kelvin (for a filled pixel) are derived for the temperatures in the tiger stripes.

  19. LSM Microelectrodes: Kinetics and Surface Composition

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Norrman, Kion; Jacobsen, Torben

    2015-01-01

    spectroscopy and cyclic voltammetry were performed on electrodes with diameters of 20–100 μm in oxygen, air and nitrogen both at open circuit voltage and at anodic and cathodic polarization. In situ conductance mapping, ex situ surface analysis by time-of-flight secondary ion mass spectrometry, and scanning...

  20. Internal/external mixing of aerosol particles elemental composition retrieved from microPIXE and PIXE

    International Nuclear Information System (INIS)

    Ghermandi, G.; Cecchi, R.; Lusvarghi, L.; Laj, P.; Zappoli, S.; Ceccato, D.

    2005-01-01

    A statistical evaluation of the association between different elements contained in atmospheric aerosol particles has been made using the microPIXE technique. We derived elemental maps of Al, Si, S, Ca, Cl, K, Fe, Mg spatial distribution on the surface of a Nuclepore filter sample. The microPIXE measurements are validated by comparison to conventional PIXE and SEM-EDAX. Then, the spatial coherence of the different elements is analysed using statistical methods. The elements are not homogeneously distributed and the association among specific elements can be identified. MicroPIXE and factorial analysis can be coupled to understand the state of mixing of the different elements on the filter surface

  1. Lunar atmosphere. How surface composition and meteoroid impacts mediate sodium and potassium in the lunar exosphere.

    Science.gov (United States)

    Colaprete, A; Sarantos, M; Wooden, D H; Stubbs, T J; Cook, A M; Shirley, M

    2016-01-15

    Despite being trace constituents of the lunar exosphere, sodium and potassium are the most readily observed species due to their bright line emission. Measurements of these species by the Ultraviolet and Visible Spectrometer (UVS) on the Lunar Atmosphere and Dust Environment Explorer (LADEE) have revealed unambiguous temporal and spatial variations indicative of a strong role for meteoroid bombardment and surface composition in determining the composition and local time dependence of the Moon's exosphere. Observations show distinct lunar day (monthly) cycles for both species as well as an annual cycle for sodium. The first continuous measurements for potassium show a more repeatable variation across lunations and an enhancement over KREEP (Potassium Rare Earth Elements and Phosphorus) surface regions, revealing a strong dependence on surface composition. Copyright © 2016, American Association for the Advancement of Science.

  2. Continuous Natural Fiber Reinforced Thermoplastic Composites by Fiber Surface Modification

    Directory of Open Access Journals (Sweden)

    Patcharat Wongsriraksa

    2013-01-01

    Full Text Available Continuous natural fiber reinforced thermoplastic materials are expected to replace inorganic fiber reinforced thermosetting materials. However, in the process of fabricating the composite, it is difficult to impregnate the thermoplastic resin into reinforcement fiber because of the high melt viscosity. Therefore, intermediate material, which allows high impregnation during molding, has been investigated for fabricating continuous fiber reinforced thermoplastic composite by aligning resin fiber alongside reinforcing fiber with braiding technique. This intermediate material has been called “microbraid yarn (MBY.” Moreover, it is well known that the interfacial properties between natural fiber and resin are low; therefore, surface treatment on continuous natural fiber was performed by using polyurethane (PU and flexible epoxy (FLEX to improve the interfacial properties. The effect of surface treatment on the mechanical properties of continuous natural fiber reinforced thermoplastic composites was examined. From these results, it was suggested that surface treatment by PU with low content could produce composites with better mechanical properties.

  3. Surface characterization of current composites after toothbrush abrasion.

    Science.gov (United States)

    Takahashi, Rena; Jin, Jian; Nikaido, Toru; Tagami, Junji; Hickel, Reinhard; Kunzelmann, Karl-Heinz

    2013-01-01

    The present study was designed to evaluate the surface roughness and the gloss of current composites before and after toothbrush abrasion. We assessed forty dimensionally standardized composite specimens (n=8/group) from five composites: two nanohybrids (i. e., IPS Empress Direct Enamel and IPS Empress Direct Dentin), two microhybrids (i. e., Clearfil AP-X and Filtek Z250) and one organically modified ceramics (Admira). All of the specimens were polished with 4000-grid silicon carbide papers. Surface roughness was measured with a profilometer and gloss was measured with a glossmeter before and after powered toothbrush abrasion with a 1:1 slurry (dentifrice/tap water) at 12,000 strokes in a toothbrush simulator. There was a significant increase in the surface roughness and a reduction in gloss after toothbrush abrasion in all of the composites except Clearfil AP-X (pgloss (R(2)=0.191, p<0.001).

  4. Surface functionalized hollow silica particles and composites

    KAUST Repository

    Rodionov, Valentin; Khanh, Vu Bao

    2017-01-01

    Composition comprising hollow spherical silica particles having outside particle walls and inside particle walls, wherein the particles have an average particle size of about 10 nm to about 500 nm and an average wall thickness of about 10 nm to about 50 nm; and wherein the particles are functionalized with at least one organic functional group on the outside particle wall, on the inside particle wall, or on both the outside and inside particle walls, wherein the organic functional group is in a reacted or unreacted form. The organic functional group can be epoxy. The particles can be mixed with polymer precursor or a polymer material such as epoxy to form a prepreg or a nanocomposite. Lightweight but strong materials can be formed. Low loadings of hollow particles can be used.

  5. Surface functionalized hollow silica particles and composites

    KAUST Repository

    Rodionov, Valentin

    2017-05-26

    Composition comprising hollow spherical silica particles having outside particle walls and inside particle walls, wherein the particles have an average particle size of about 10 nm to about 500 nm and an average wall thickness of about 10 nm to about 50 nm; and wherein the particles are functionalized with at least one organic functional group on the outside particle wall, on the inside particle wall, or on both the outside and inside particle walls, wherein the organic functional group is in a reacted or unreacted form. The organic functional group can be epoxy. The particles can be mixed with polymer precursor or a polymer material such as epoxy to form a prepreg or a nanocomposite. Lightweight but strong materials can be formed. Low loadings of hollow particles can be used.

  6. Mineralogy of the Martian Surface: Crustal Composition to Surface Processes

    Science.gov (United States)

    Mustard, John F.

    1999-01-01

    Over the course of this award we have: 1) Completed and published the results of a study of the effects of hyperfine particles on reflectance spectra of olivine and quartz, which included the development of scattering codes. Research has also progressed in the analysis of the effects of fine particle sizes on clay spectra. 2) Completed the analysis of the mineralogy of dark regions, showed the insitu compositions are highly correlated to the SNC meteorites, and determined that the martian mantle was depleted in aluminum prior to 2-3 GA ago; Studies of the mineralogic heterogeneity of surficial materials on Mars have also been conducted. and 3) Performed initial work on the study of the physical and chemical processes likely to form and modify duricrust. This includes assessments of erosion rates, solubility and transport of iron in soil environments, and models of pedogenic crust formation.

  7. Trace element composition of hair in the Italian population

    International Nuclear Information System (INIS)

    Clemente, G.F.; Cigna Rossi, L.

    1979-01-01

    The content of the trace elements Ag, Co, Cr, Cs, Fe, Hg, Ni, Rb, Sb, Sc, Se and Zn has been evaluated in hair samples collected from five different groups of subjects in Italy. All the measurements were performed by means of non-destructive neutron activation analysis of the hair samples that were carefully washed before analysis. In most of the samples the Cs, Rb and Sc content was below the detection limit of the analytical method. Each population group was formed of about five individuals of each sex, selected to be representative of the adult population living in a well-defined community. The five groups were chosen from distinct regions with different socio-economical living habits in order to detect the variability, if any, of the trace element burden among the Italian population. The trace element hair concentration of each subject was correlated with the trace element blood concentration and daily urinary excretion in order to differentiate the trace element content due to exogenous deposition on hair from that due to endogenous absorption routes. The results obtained show that the variability of the hair content among the various groups is strongly linked to local environmental factors. The histograms of the individual values of the hair concentration are given for all trace elements measured, together with a statistical analysis of all data. (author)

  8. Surface roughness of composite resins subjected to hydrochloric acid.

    Science.gov (United States)

    Roque, Ana Carolina Cabral; Bohner, Lauren Oliveira Lima; de Godoi, Ana Paula Terossi; Colucci, Vivian; Corona, Silmara Aparecida Milori; Catirse, Alma Blásida Concepción Elizaur Benitez

    2015-01-01

    The purpose of this study was to determine the influence of hydrochloric acid on surface roughness of composite resins subjected to brushing. Sixty samples measuring 2 mm thick x 6 mm diameter were prepared and used as experimental units. The study presented a 3x2 factorial design, in which the factors were composite resin (n=20), at 3 levels: microhybrid composite (Z100), nanofilled composite (FiltekTM Supreme), nanohybrid composite (Ice), and acid challenge (n=10) at 2 levels: absence and presence. Acid challenge was performed by immersion of specimens in hydrochloric acid (pH 1.2) for 1 min, 4 times per day for 7 days. The specimens not subjected to acid challenge were stored in 15 mL of artificial saliva at 37 oC. Afterwards, all specimens were submitted to abrasive challenge by a brushing cycle performed with a 200 g weight at a speed of 356 rpm, totaling 17.8 cycles. Surface roughness measurements (Ra) were performed and analyzed by ANOVA and Tukey test (p≤0.05). Surface roughness values were higher in the presence (1.07±0.24) as compared with the absence of hydrochloric acid (0.72±0.04). Surface roughness values were higher for microhybrid (1.01±0.27) compared with nanofilled (0.68 ±0.09) and nanohybrid (0.48±0.15) composites when the specimens were not subjects to acid challenge. In the presence of hydrochloric acid, microhybrid (1.26±0.28) and nanofilled (1.18±0,30) composites presents higher surface roughness values compared with nanohybrid (0.77±0.15). The hydrochloric acid affected the surface roughness of composite resin subjected to brushing.

  9. Probability of misclassifying biological elements in surface waters.

    Science.gov (United States)

    Loga, Małgorzata; Wierzchołowska-Dziedzic, Anna

    2017-11-24

    Measurement uncertainties are inherent to assessment of biological indices of water bodies. The effect of these uncertainties on the probability of misclassification of ecological status is the subject of this paper. Four Monte-Carlo (M-C) models were applied to simulate the occurrence of random errors in the measurements of metrics corresponding to four biological elements of surface waters: macrophytes, phytoplankton, phytobenthos, and benthic macroinvertebrates. Long series of error-prone measurement values of these metrics, generated by M-C models, were used to identify cases in which values of any of the four biological indices lay outside of the "true" water body class, i.e., outside the class assigned from the actual physical measurements. Fraction of such cases in the M-C generated series was used to estimate the probability of misclassification. The method is particularly useful for estimating the probability of misclassification of the ecological status of surface water bodies in the case of short sequences of measurements of biological indices. The results of the Monte-Carlo simulations show a relatively high sensitivity of this probability to measurement errors of the river macrophyte index (MIR) and high robustness to measurement errors of the benthic macroinvertebrate index (MMI). The proposed method of using Monte-Carlo models to estimate the probability of misclassification has significant potential for assessing the uncertainty of water body status reported to the EC by the EU member countries according to WFD. The method can be readily applied also in risk assessment of water management decisions before adopting the status dependent corrective actions.

  10. Induced wettability and surface-volume correlation of composition for bovine bone derived hydroxyapatite particles

    Science.gov (United States)

    Maidaniuc, Andreea; Miculescu, Florin; Voicu, Stefan Ioan; Andronescu, Corina; Miculescu, Marian; Matei, Ecaterina; Mocanu, Aura Catalina; Pencea, Ion; Csaki, Ioana; Machedon-Pisu, Teodor; Ciocan, Lucian Toma

    2018-04-01

    Hydroxyapatite powders characteristics need to be determined both for quality control purposes and for a proper control of microstructural features of bone reconstruction products. This study combines bulk morphological and compositional analysis methods (XRF, SEM-EDS, FT-IR) with surface-related methods (XPS, contact angle measurements) in order to correlate the characteristics of hydroxyapatite powders derived from bovine bone for its use in medical applications. An experimental approach for correlating the surface and volume composition was designed based on the analysis depth of each spectral method involved in the study. Next, the influences of powder particle size and forming method on the contact angle between water drops and ceramic surface were evaluated for identifying suitable strategies of tuning hydroxyapatite's wettability. The results revealed a preferential arrangement of chemical elements at the surface of hydroxyapatite particles which could induce a favourable material behaviour in terms of sinterability and biological performance.

  11. The elemental composition of airborne particle in the Bangkok area

    Energy Technology Data Exchange (ETDEWEB)

    Sirinuntavid, Alice [Chemistry Division, Office of Atomic Energy for Peace, Chatuchak, Bangkok (Thailand); Pentamwa, Prapat [Environmental Scientist, Pollution Control Department, Bangkok (Thailand)

    1999-10-01

    Neutron Activation Analysis (NAA) has been applied to analyze the total suspended particle (TSP) airborne matter from two selected sites in the Bangkok city area. High volume air samplers were operated to collect TSP matter on cellulose nitrate membrane filters once a month throughout 1997. 20 elements were analyzed and Zn, Br, As, Sb, Cu, Cl were found with high enrichment factor at both sites. The enrichment factor of 20 elements in TSP of both sites gave the same interesting pattern. To studying the validation of the NAA technique, the standard reference material 1648, urban particulate matter, was analyzed and presented also. (author)

  12. The elemental composition of airborne particle in the Bangkok area

    International Nuclear Information System (INIS)

    Sirinuntavid, Alice; Pentamwa, Prapat

    1999-01-01

    Neutron Activation Analysis (NAA) has been applied to analyze the total suspended particle (TSP) airborne matter from two selected sites in the Bangkok city area. High volume air samplers were operated to collect TSP matter on cellulose nitrate membrane filters once a month throughout 1997. 20 elements were analyzed and Zn, Br, As, Sb, Cu, Cl were found with high enrichment factor at both sites. The enrichment factor of 20 elements in TSP of both sites gave the same interesting pattern. To studying the validation of the NAA technique, the standard reference material 1648, urban particulate matter, was analyzed and presented also. (author)

  13. Correlative Imaging of Structural and Elemental Composition of Bacterial Biofilms

    International Nuclear Information System (INIS)

    Yang, Y; Heine, R; Xu, F; Helfen, L; Baumbach, T; Suhonen, H; Rosenhahn, A; Gorniak, T; Kirchen, S; Schwartz, T

    2013-01-01

    Synchrotron-based phase contrast tomography (holotomography) and scanning hard X-ray fluorescence microscopy (SXFM) are combined to characterize the three-dimensional (3D) structural and corresponding elemental distribution of bacterial biofilms of Pseudomonas aeruginosa. Samples were fixed without contrast agents or microtomal sectioning. Within an intact microbial community single bacteria are clearly resolved, and their morphology can be directly visualized together with the elemental content. Such 3D set of complementary information at cellular level is essential for gaining a deeper understanding of biofilm evolution aiming to develop potential strategies on biofilm growth control and prevention

  14. The effect of melt composition on the partitioning of trace elements between titanite and silicate melt

    Science.gov (United States)

    Prowatke, S.; Klemme, S.

    2003-04-01

    The aim of this study is to systematically investigate the influence of melt composition on the partitioning of trace elements between titanite and different silicate melts. Titanite was chosen because of its important role as an accessory mineral, particularly with regard to intermediate to silicic alkaline and calc-alkaline magmas [e.g. 1] and of its relative constant mineral composition over a wide range of bulk compositions. Experiments at atmospheric pressure were performed at temperatures between 1150°C and 1050°C. Bulk compositions were chosen to represent a basaltic andesite (SH3 - 53% SiO2), a dacite (SH2 - 65 SiO2) and a rhyolite (SH1 - 71% SiO2). Furthermore, two additional experimental series were conducted to investigate the effect of Al-Na and the Na-K ratio of melts on partitioning. Starting materials consisted of glasses that were doped with 23 trace elements including some selected rare earth elements (La, Ce, Pr, Sm, Gd, Lu), high field strength elements (Zr, Hf, Nb, Ta) and large ion lithophile elements (Cs, Rb, Ba) and Th and U. The experimental run products were analysed for trace elements using secondary ion mass spectrometry at Heidelberg University. Preliminary results indicate a strong effect of melt composition on trace element partition coefficients. Partition coefficients for rare-earth elements uniformly show a convex-upward shape [2, 3], since titanite accommodates the middle rare-earth elements more readily than the light rare-earth elements or the heavy rare-earth elements. Partition coefficients for the rare-earth elements follow a parabolic trend when plotted against ionic radius. The shape of the parabola is very similar for all studied bulk compositions, the position of the parabola, however, is strongly dependent on bulk composition. For example, isothermal rare-earth element partition coefficients (such as La) are incompatible (D>1) in alkali-poor melt compositions. From our experimental data we present an model that combines

  15. What controls the isotopic composition of Greenland surface snow?

    Directory of Open Access Journals (Sweden)

    H. C. Steen-Larsen

    2014-02-01

    Full Text Available Water stable isotopes in Greenland ice core data provide key paleoclimatic information, and have been compared with precipitation isotopic composition simulated by isotopically enabled atmospheric models. However, post-depositional processes linked with snow metamorphism remain poorly documented. For this purpose, monitoring of the isotopic composition (δ18O, δD of near-surface water vapor, precipitation and samples of the top (0.5 cm snow surface has been conducted during two summers (2011–2012 at NEEM, NW Greenland. The samples also include a subset of 17O-excess measurements over 4 days, and the measurements span the 2012 Greenland heat wave. Our observations are consistent with calculations assuming isotopic equilibrium between surface snow and water vapor. We observe a strong correlation between near-surface vapor δ18O and air temperature (0.85 ± 0.11‰ °C−1 (R = 0.76 for 2012. The correlation with air temperature is not observed in precipitation data or surface snow data. Deuterium excess (d-excess is strongly anti-correlated with δ18O with a stronger slope for vapor than for precipitation and snow surface data. During nine 1–5-day periods between precipitation events, our data demonstrate parallel changes of δ18O and d-excess in surface snow and near-surface vapor. The changes in δ18O of the vapor are similar or larger than those of the snow δ18O. It is estimated using the CROCUS snow model that 6 to 20% of the surface snow mass is exchanged with the atmosphere. In our data, the sign of surface snow isotopic changes is not related to the sign or magnitude of sublimation or deposition. Comparisons with atmospheric models show that day-to-day variations in near-surface vapor isotopic composition are driven by synoptic variations and changes in air mass trajectories and distillation histories. We suggest that, in between precipitation events, changes in the surface snow isotopic composition are driven by these changes in near-surface

  16. Assessment of elemental composition and distribution of some ...

    African Journals Online (AJOL)

    Nigerian Journal of Physics ... The MOP fertilizer has the highest mean concentration levels for both As and Pb, followed by SSP fertilizer, which recorded As and Pb concentration level s of 161±50 ppm and 231±68 ppm, respectively. ... Keywords: chemical elements, fertilizers, concentration levels, PBTs, chemical toxicity ...

  17. 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.

  18. Bending analysis of laminated composite plates using finite element ...

    African Journals Online (AJOL)

    user

    theory to analyze the laminated composite plates. They concluded that ...... Aeronautics and Astronautics”, Inc.1801, Chapter 8, pp. 240. Baltacıoğlu A.K .... He is working as Assistant Professor in the Department of Mechanical. Engineering in ...

  19. Anterior esthetics and the visual arts: beauty, elements of composition, and their clinical application to dentistry.

    Science.gov (United States)

    Valo, T S

    1995-01-01

    The challenge of developing a pleasing smile is an artistic venture. A study of how the visual arts have explored the nature of beauty and the elements of artistic composition will enhance our artistic abilities in cosmetic dentistry. This review discusses the perception of beauty and important features of that which we call beautiful. The discussion uses important works of art to demonstrate elements of composition, which are then made relevant in a dental application.

  20. Tribological behaviors of UHMWPE composites with different counter surface morphologies

    Science.gov (United States)

    Wang, Yanzhen; Yin, Zhongwei; Li, Hulin; Gao, Gengyuan

    2017-12-01

    The influence of counter surface morphologies on hybrid glass fiber (GF) and carbon fiber (CF) filled ultrahigh molecular weight polyethylene (UHMWPE) were studied under various contact pressure and sliding speed against GCr15 steel in dry condition. The goals were to investigate the tribological behavior of GF/CF/UHMWPE composite as a kind of water lubricated journal bearing material. The friction and wear behavior of composites were examined using a pin-on-disc tribometer. The morphologies of the worn surface were examined by scanning electron microscopy (SEM) and laser 3D micro-imaging and profile measurement. Generally, the wear rate and friction coefficient of composites increase as the increment of counter surface roughness. The friction coefficient increases firstly and then decrease with an increase in sliding speed and contact pressure for counterface with Ra=0.2 and 3.5 μm, while the friction coefficient decreased for counterface with Ra=0.6 μm.

  1. Composites reinforced via mechanical interlocking of surface-roughened microplatelets within ductile and brittle matrices.

    Science.gov (United States)

    Libanori, R; Carnelli, D; Rothfuchs, N; Binelli, M R; Zanini, M; Nicoleau, L; Feichtenschlager, B; Albrecht, G; Studart, A R

    2016-04-12

    Load-bearing reinforcing elements in a continuous matrix allow for improved mechanical properties and can reduce the weight of structural composites. As the mechanical performance of composite systems are heavily affected by the interfacial properties, tailoring the interactions between matrices and reinforcing elements is a crucial problem. Recently, several studies using bio-inspired model systems suggested that interfacial mechanical interlocking is an efficient mechanism for energy dissipation in platelet-reinforced composites. While cheap and effective solutions are available at the macroscale, the modification of surface topography in micron-sized reinforcing elements still represents a challenging task. Here, we report a simple method to create nanoasperities with tailored sizes and densities on the surface of alumina platelets and investigate their micromechanical effect on the energy dissipation mechanisms of nacre-like materials. Composites reinforced with roughened platelets exhibit improved mechanical properties for both organic ductile epoxy and inorganic brittle cement matrices. Mechanical interlocking increases the modulus of toughness (area under the stress-strain curve) by 110% and 56% in epoxy and cement matrices, respectively, as compared to those reinforced with flat platelets. This interlocking mechanism can potentially lead to a significant reduction in the weight of mechanical components while retaining the structural performance required in the application field.

  2. Trace Elements in the Sea Surface Microlayer: Results from a Two Year Study in the Florida Keys

    Science.gov (United States)

    Ebling, A. M.; Westrich, J. R.; Lipp, E. K.; Mellett, T.; Buck, K. N.; Landing, W. M.

    2016-02-01

    Natural and anthropogenic aerosols are a significant source of trace elements to oligotrophic ocean surface waters, where they provide episodic pulses of limiting micronutrients for the microbial community. Opportunistic bacteria have been shown to experience rapid growth during deposition events. However, little is known about the fate of trace elements at the air-sea interface, i.e. the sea surface microlayer. It has been hypothesized that dust particles would be retained in the sea surface microlayer long enough to undergo chemical and physical changes that would affect the bioavailability of trace elements. In this study, aerosols, sea surface microlayer, and underlying water column samples were collected in the Florida Keys in July 2014 and May 2015 at various locations and analyzed for a suite of dissolved and particulate trace elements. Sea surface microlayer samples ( 50 μm) were collected using a cylinder of ultra-pure quartz glass; a novel adaptation of the glass plate technique. Sampling sites ranged from a more pristine environment approximately ten kilometers offshore to a more anthropogenic environment within a shallow bay a few hundred meters offshore. While it was clear from the results that dust deposition events played a large role in the chemical composition of the sea surface microlayer (elevated concentrations in dissolved and particulate trace elements associated with dust deposition), the location where the samples were collected also had a large impact on the sea surface microlayer as well as the underlying water column. The results were compared with other parameters analyzed such as Vibrio cultures as well as iron speciation, providing an important step towards our goal of understanding of the fate of trace elements in the sea surface microlayer as well as the specific effects of aeolian dust deposition on heterotrophic microbes in the upper ocean.

  3. Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore Emiliania huxleyi

    Science.gov (United States)

    Feng, Yuanyuan; Roleda, Michael Y.; Armstrong, Evelyn; Law, Cliff S.; Boyd, Philip W.; Hurd, Catriona L.

    2018-01-01

    A series of semi-continuous incubation experiments were conducted with the coccolithophore Emiliania huxleyi strain NIWA1108 (Southern Ocean isolate) to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial pressure of CO2 (pCO2)) on both the physiological rates and elemental composition of the coccolithophore. Here, we report the alteration of the elemental composition of E. huxleyi in response to the changes in these environmental drivers. A series of dose-response curves for the cellular elemental composition of E. huxleyi were fitted for each of the five drivers across an environmentally representative gradient. The importance of each driver in regulating the elemental composition of E. huxleyi was ranked using a semi-quantitative approach. The percentage variations in elemental composition arising from the change in each driver between present-day and model-projected conditions for the year 2100 were calculated. Temperature was the most important driver controlling both cellular particulate organic and inorganic carbon content, whereas nutrient concentrations were the most important regulator of cellular particulate nitrogen and phosphorus of E. huxleyi. In contrast, elevated pCO2 had the greatest influence on cellular particulate inorganic carbon to organic carbon ratio, resulting in a decrease in the ratio. Our results indicate that the different environmental drivers play specific roles in regulating the elemental composition of E. huxleyi with wide-reaching implications for coccolithophore-related marine biogeochemical cycles, as a consequence of the regulation of E. huxleyi physiological processes.

  4. Elemental composition of suspended particles released in refuse incineration

    International Nuclear Information System (INIS)

    Mamuro, Tetsuo; Mizohata, Akira

    1979-01-01

    Suspended particles released in refuse incineration were subjected to multielement analysis by means of instrumental neutron activation method and energy dispersive X-ray fluorescence spectrometry. The analytical results were compared with the elemental concentrations observed in the urban atmosphere, and the contribution of the refuse incineration to the urban atmosphere was roughly estimated. Greenberg et al. pointed out on the basis of their analyses that the refuse incineration can account for major portions of the Zn, Cd and Sb observed on urban aerosols. According to our results, the contribution of the refuse incineration for Zn, Cd and Sb is not negligible, but not so serious as in U.S.A. big cities. In Japan big cities there must be other more important sources of these elements. (author)

  5. Reversible Compositional Control of Oxide Surfaces by Electrochemical Potentials

    KAUST Repository

    Mutoro, Eva

    2012-01-05

    Perovskite oxides can exhibit a wide range of interesting characteristics such as being catalytically active and electronically/ionically conducting, and thus, they have been used in a number of solid-state devices such as solid oxide fuel cells (SOFCs) and sensors. As the surface compositions of perovskites can greatly influence the catalytic properties, knowing and controlling their surface compositions is crucial to enhance device performance. In this study, we demonstrate that the surface strontium (Sr) and cobalt (Co) concentrations of perovskite-based thin films can be controlled reversibly at elevated temperatures by applying small electrical potential biases. The surface compositional changes of La 0.8Sr 0.2CoO 3-δ (LSC 113), (La 0.5Sr 0.5) 2CoO 4±δ (LSC 214), and LSC 214-decorated LSC 113 films (LSC 113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr were found for the LSC 113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites. © 2011 American Chemical Society.

  6. Surface analysis of graphite fiber reinforced polyimide composites

    Science.gov (United States)

    Messick, D. L.; Progar, D. J.; Wightman, J. P.

    1983-01-01

    Several techniques have been used to establish the effect of different surface pretreatments on graphite-polyimide composites. Composites were prepared from Celion 6000 graphite fibers and the polyimide LARC-160. Pretreatments included mechanical abrasion, chemical etching and light irradiation. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used in the analysis. Contact angle of five different liquids of varying surface tensions were measured on the composites. SEM results showed polymer-rich peaks and polymer-poor valleys conforming to the pattern of the release cloth used durng fabrication. Mechanically treated and light irradiated samples showed varying degrees of polymer peak removal, with some degradation down to the graphite fibers. Minimal changes in surface topography were observed on concentrations of surface fluorine even after pretreatment. The light irradiation pretreatment was most effective at reducing surface fluorine concentrations whereas chemical pretreatment was the least effective. Critical surface tensions correlated directly with the surface fluorine to carbon ratios as calculated from XPS.

  7. Surface characterization of modern resin composites: a multitechnique approach.

    Science.gov (United States)

    Silikas, Nick; Kavvadia, Katerina; Eliades, George; Watts, David

    2005-04-01

    To characterize the surface properties of some modern resin composites employing a series of physicochemical methods. Specimens from three microhybrid (Palfique Estellite-PE, Z250 Filtek-ZF, Tetric Ceram-TC) and one nanofilled (Supreme Filtek-SF) conventionally photo-cured resin composites polished with Soflex disks were studied for the following properties: Surface chemical composition and degree of C=C conversion (FTIR), surface energetics (contact angles), surface texture (AFM), surface roughness (AFM, stylus profilometry) and gloss (60 degrees-, 20 degrees-angle specular gloss). Polar and non polar molecular groups were identified in all products including NH and CONH (SF, ZF, TC). SF and ZF demonstrated higher conversion than PE and TC (P 0.05) were found in critical surface tension, total work of adhesion and its polar and dispersion components, the latter being the highest in all products. AFM showed the smoothest surface texture in PE. The ranking of Sa, Sq, Ra and Rz roughness parameters was PEgloss measurements (PE, SF>ZF>TC, PTC, Pgloss differences. A positive correlation was found between Sa and Ra and a negative one between Sa and 20 degree-angle gloss.

  8. Dimensional and Compositional Change of 1D Chalcogen Nanostructures Leading to Tunable Localized Surface Plasmon Resonances.

    Science.gov (United States)

    Min, Yuho; Seo, Ho Jun; Choi, Jong-Jin; Hahn, Byung-Dong; Moon, Geon Dae

    2018-05-31

    As the oxygen family, chalcogen (Se, Te) nanostructures have been considered important elements for various practical fields and further exploited to constitute metal chalcogenides for each targeted application. Here we report a controlled synthesis of well-defined one-dimensional chalcogen nanostructures such as nanowries, nanorods, and nanotubes by controlling reduction reaction rate to fine-tune the dimension and composition of the products. Tunable optical properties (localized surface plasmon resonances) of these chalcogen nanostructures are observed depending on their morphological, dimensional, and compositional variation. © 2018 IOP Publishing Ltd.

  9. 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.

  10. The Origin of the Compositional Diversity of Mercury's Surface Constrained From Experimental Melting of Enstatite Chondrites

    Science.gov (United States)

    Boujibar, A.; Righter, K.; Pando, K.; Danielson, L.

    2015-01-01

    Mercury is known as an endmember planet as it is the most reduced terrestrial planet with the highest core/mantle ratio. MESSENGER spacecraft has shown that its surface is FeO-poor (2-4 wt%) and Srich (up to 6-7 wt%), which confirms the reducing nature of its silicate mantle. Moreover, high resolution images revealed large volcanic plains and abundant pyroclastic deposits, suggesting important melting stages of the Mercurian mantle. This interpretation was confirmed by the high crustal thickness (up to 100 km) derived from Mercury's gravity field. This is also corroborated by a recent experimental result that showed that Mercurian partial melts are expected to be highly buoyant within the Mercurian mantle and could have risen from depths as high as the core-mantle boundary. In addition MESSENGER spacecraft provided relatively precise data on major elemental compositions of Mercury's surface. These results revealed important chemical and mineralogical heterogeneities that suggested several stages of differentiation and re-melting processes. However, the extent and nature of compositional variations produced by partial melting remains poorly constrained for the particular compositions of Mercury (very reducing conditions, low FeO-contents and high sulfur-contents). Therefore, in this study, we investigated the processes that lead to the various compositions of Mercury's surface. Melting experiments with bulk Mercury-analogue compositions were performed and compared to the compositions measured by MESSENGER.

  11. Surface treated fly ash filled modified epoxy composites

    Directory of Open Access Journals (Sweden)

    Uma Dharmalingam

    2015-01-01

    Full Text Available Abstract Fly ash, an inorganic alumino silicate has been used as filler in epoxy matrix, but it reduces the mechanical properties due to its poor dispersion and interfacial bonding with the epoxy matrix. To improve its interfacial bonding with epoxy matrix, surface treatment of fly ash was done using surfactant sodium lauryl sulfate and silane coupling agent glycidoxy propyl trimethoxy silane. An attempt is also made to reduce the particle size of fly ash using high pressure pulverizer. To improve fly ash dispersion in epoxy matrix, the epoxy was modified by mixing with amine containing liquid silicone rubber (ACS. The effect of surface treated fly ash with varying filler loadings from 10 to 40% weight on the mechanical, morphological and thermal properties of modified epoxy composites was investigated. The surface treated fly ash was characterized by particle size analyzer and FTIR spectra. Morphological studies of surface treated fly ash filled modified epoxy composites indicate good dispersion of fillers in the modified epoxy matrix and improves its mechanical properties. Impact strength of the surface treated fly ash filled modified epoxy composites show more improvement than unmodified composites.

  12. 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...

  13. Method and coating composition for protecting and decontaminating surfaces

    Science.gov (United States)

    Overhold, D C; Peterson, M D

    1959-03-10

    A protective coating useful in the decontamination of surfaces exposed to radioactive substances is described. This coating is placed on the surface before use and is soluble in water, allowing its easy removal in the event decontamination becomes necessary. Suitable coating compositions may be prepared by mixing a water soluble carbohydrate such as sucrose or dextrin, together with a hygroscopic agent such as calcium chloride or zinc chloride.

  14. A nonlinear efficient layerwise finite element model for smart piezolaminated composites under strong applied electric field

    International Nuclear Information System (INIS)

    Kapuria, S; Yaqoob Yasin, M

    2013-01-01

    In this work, we present an electromechanically coupled efficient layerwise finite element model for the static response of piezoelectric laminated composite and sandwich plates, considering the nonlinear behavior of piezoelectric materials under strong electric field. The nonlinear model is developed consistently using a variational principle, considering a rotationally invariant second order nonlinear constitutive relationship, and full electromechanical coupling. In the piezoelectric layer, the electric potential is approximated to have a quadratic variation across the thickness, as observed from exact three dimensional solutions, and the equipotential condition of electroded piezoelectric surfaces is modeled using the novel concept of an electric node. The results predicted by the nonlinear model compare very well with the experimental data available in the literature. The effect of the piezoelectric nonlinearity on the static response and deflection/stress control is studied for piezoelectric bimorph as well as hybrid laminated plates with isotropic, angle-ply composite and sandwich substrates. For high electric fields, the difference between the nonlinear and linear predictions is large, and cannot be neglected. The error in the prediction of the smeared counterpart of the present theory with the same number of primary displacement unknowns is also examined. (paper)

  15. Strength and failure analysis of composite-to-composite adhesive bonds with different surface treatments

    Science.gov (United States)

    Paranjpe, Nikhil; Alamir, Mohammed; Alonayni, Abdullah; Asmatulu, Eylem; Rahman, Muhammad M.; Asmatulu, Ramazan

    2018-03-01

    Adhesives are widely utilized materials in aviation, automotive, energy, defense, and marine industries. Adhesive joints are gradually supplanting mechanical fasteners because they are lightweight structures, thus making the assembly lighter and easier. They also act as a sealant to prevent a structural joint from galvanic corrosion and leakages. Adhesive bonds provide high joint strength because of the fact that the load is distributed uniformly on the joint surface, while in mechanical joints, the load is concentrated at one point, thus leading to stress at that point and in turn causing joint failures. This research concentrated on the analysis of bond strength and failure loads in adhesive joint of composite-to-composite surfaces. Different durations of plasma along with the detergent cleaning were conducted on the composite surfaces prior to the adhesive applications and curing processes. The joint strength of the composites increased about 34% when the surface was plasma treated for 12 minutes. It is concluded that the combination of different surface preparations, rather than only one type of surface treatment, provides an ideal joint quality for the composites.

  16. Isotopic composition of chemical elements in natural cycles

    International Nuclear Information System (INIS)

    Wetzel, K.

    1977-12-01

    Mathematical models developed for planning and evaluating tracer experiments have been applied in investigations of the isotopic composition of carbon in its natural cycle through various periods of the last billion years. The influence on the natural isotope ratio due to industrial combustion of fossil fuels is shown. In order to describe regional differences from the global behaviour of carbon a parameter has been introduced, which represents the time needed for one total exchange of the atmosphere in a certain region with the global atmosphere

  17. Nonlinear vibrations of thin arbitrarily laminated composite plates subjected to harmonic excitations using DKT elements

    Science.gov (United States)

    Chiang, C. K.; Xue, David Y.; Mei, Chuh

    1993-04-01

    A finite element formulation is presented for determining the large-amplitude free and steady-state forced vibration response of arbitrarily laminated anisotropic composite thin plates using the Discrete Kirchhoff Theory (DKT) triangular elements. The nonlinear stiffness and harmonic force matrices of an arbitrarily laminated composite triangular plate element are developed for nonlinear free and forced vibration analyses. The linearized updated-mode method with nonlinear time function approximation is employed for the solution of the system nonlinear eigenvalue equations. The amplitude-frequency relations for convergence with gridwork refinement, triangular plates, different boundary conditions, lamination angles, number of plies, and uniform versus concentrated loads are presented.

  18. 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......, where full access to the finite element analysis core is granted. This comparison displays the possibility of using commercially available programs for stiffness design of laminated composite structures....

  19. 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.

  20. Composition containing transuranic elements for use in the homeopathic treatment of aids

    International Nuclear Information System (INIS)

    Lustig, D.

    1996-01-01

    A homeopathic remedy consisting of a composition containing one or more transuranic elements, particularly plutonium, for preventing and treating acquired immunodeficiency syndrome (AIDS) in humans, as well as seropositivity for human immunodeficiency virus (HIV). Said composition is characterized in that it uses any chemical or isotopic form of one or more transuranic elements (neptunium, plutonium, americium, curium, berkelium, californium or einsteinium), particularly plutonium, said form being diluted and dynamized according to conventional homeopathic methods, particularly the so-called Hahnemann and Korsakov methods, and provided preferably but not exclusively in the form of lactose and/or saccharose globules or granules impregnated with the active principle of said composition. (author)

  1. Plasma facing surface composition during NSTX Li experiments

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, C.H., E-mail: cskinner@pppl.gov [Princeton Plasma Physics Laboratory, POB 451, Princeton, NJ 08543 (United States); Sullenberger, R. [Department of Mechanical and Aerospace Engineering, Princeton University, NJ 08540 (United States); Koel, B.E. [Department of Chemical and Biological Engineering, Princeton University, NJ 08540 (United States); Jaworski, M.A.; Kugel, H.W. [Princeton Plasma Physics Laboratory, POB 451, Princeton, NJ 08543 (United States)

    2013-07-15

    Lithium conditioned plasma facing surfaces have lowered recycling and enhanced plasma performance on many fusion devices. However, the nature of the plasma–lithium surface interaction has been obscured by the difficulty of in-tokamak surface analysis. We report laboratory studies of the chemical composition of lithium surfaces exposed to typical residual gases found in tokamaks. Solid lithium and a molybdenum alloy (TZM) coated with lithium have been examined using X-ray photoelectron spectroscopy, temperature programmed desorption, and Auger electron spectroscopy both in ultrahigh vacuum conditions and after exposure to trace gases. Lithium surfaces near room temperature were oxidized after exposure to 1–2 Langmuirs of oxygen or water vapor. The oxidation rate by carbon monoxide was four times less. Lithiated PFC surfaces in tokamaks will be oxidized in about 100 s depending on the tokamak vacuum conditions.

  2. Methanol Oxidation on Model Elemental and Bimetallic Transition Metal Surfaces

    DEFF Research Database (Denmark)

    Tritsaris, G. A.; Rossmeisl, J.

    2012-01-01

    Direct methanol fuel cells are a key enabling technology for clean energy conversion. Using density functional theory calculations, we study the methanol oxidation reaction on model electrodes. We discuss trends in reactivity for a set of monometallic and bimetallic transition metal surfaces, flat...... sites on the surface and to screen for novel bimetallic surfaces of enhanced activity. We suggest platinum copper surfaces as promising anode catalysts for direct methanol fuel cells....

  3. Composite sampling of a Bacillus anthracis surrogate with cellulose sponge surface samplers from a nonporous surface.

    Directory of Open Access Journals (Sweden)

    Jenia A M Tufts

    Full Text Available A series of experiments was conducted to explore the utility of composite-based collection of surface samples for the detection of a Bacillus anthracis surrogate using cellulose sponge samplers on a nonporous stainless steel surface. Two composite-based collection approaches were evaluated over a surface area of 3716 cm2 (four separate 929 cm2 areas, larger than the 645 cm2 prescribed by the standard Centers for Disease Control (CDC and Prevention cellulose sponge sampling protocol for use on nonporous surfaces. The CDC method was also compared to a modified protocol where only one surface of the sponge sampler was used for each of the four areas composited. Differences in collection efficiency compared to positive controls and the potential for contaminant transfer for each protocol were assessed. The impact of the loss of wetting buffer from the sponge sampler onto additional surface areas sampled was evaluated. Statistical tests of the results using ANOVA indicate that the collection of composite samples using the modified sampling protocol is comparable to the collection of composite samples using the standard CDC protocol (p  =  0.261. Most of the surface-bound spores are collected on the first sampling pass, suggesting that multiple passes with the sponge sampler over the same surface may be unnecessary. The effect of moisture loss from the sponge sampler on collection efficiency was not significant (p  =  0.720 for both methods. Contaminant transfer occurs with both sampling protocols, but the magnitude of transfer is significantly greater when using the standard protocol than when the modified protocol is used (p<0.001. The results of this study suggest that composite surface sampling, by either method presented here, could successfully be used to increase the surface area sampled per sponge sampler, resulting in reduced sampling times in the field and decreased laboratory processing cost and turn-around times.

  4. 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.

  5. Analysis of surface hardness of artificially aged resin composites

    Directory of Open Access Journals (Sweden)

    Denise Cremonezzi Tornavoi

    2012-02-01

    Full Text Available This study evaluated the effect of artificially accelerated aging (AAA on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05, ANOVA and Tukey test (p < 0.05. With regard to hardness (F = 86.74, p < 0.0001 the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53. In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002. It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

  6. Influence of Ear Surface Area on Heat Tolerance of Composite ...

    African Journals Online (AJOL)

    Relative importance of ear surface area on heat tolerance of composite rabbit population was evaluated. The study was conducted during the dry and rainy seasons, climatic data were recorded to obtain categorical heat stress index. Physiological parameters, growth performance, ear length and ear width of the rabbits ...

  7. Phase spectral composition of wind generated ocean surface waves

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    A study of the composition of the phase spectra of wind generated ocean surface waves is carried out using wave records collected employing a ship borne wave recorder. It is found that the raw phase spectral estimates could be fitted by the Uniform...

  8. Importance of the elemental composition in brachytherapy with neutrons

    International Nuclear Information System (INIS)

    Paredes G, L.; Balcazar G, M.; Azorin N, J.; Francois L, J.L.

    2004-01-01

    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 252 Cf, to optimize and to individualize the treatments to the patients. (Author)

  9. MULTILAYER COMPOSITE PLASMA COATINGS ON SCREEN PROTECTION ELEMENTS BASED ON ZIRCONIUM DIOXIDE

    Directory of Open Access Journals (Sweden)

    V. A. Okovity

    2017-01-01

    Full Text Available The paper contains results of investigations pertaining to an influence of plasma jet parameters (current, spraying distance, consumption of plasma formation gas (nitrogen, fractional composition of initial powder and degree of cooling with compressed air on anti-meteoric coating characteristics. Optimum modes (arc current 600 A; spray distance of 110 mm; consumption of plasma formation gas (nitrogen – 50 l/min; fractional composition of zirconium dioxide powder <50 μm; compressed air consumption for cooling – 1 m3/min; p = 4 bar make it possible to obtain anti-meteoric coatings based on zirconium dioxide with material utilization rate of 62 %, total ceramic layer porosity of 6 %. After exposure of compression plasma flows on a coating in the nitrogen atmosphere a cubic modification of zirconium oxide is considered as the main phase being present in the coating. The lattice parameter of cubic zirconium oxide modification is equal to 0.5174 nm. Taking into consideration usage of nitrogen as plasma formation substance its interaction with zirconium coating atoms occurs and zirconium nitride (ZrN is formed with a cubic crystal lattice (lattice parameter 0.4580 nm. Melting of pre-surface layer takes place and a depth of the melted layer is about 8 μm according to the results of a scanning electron microscopy. Pre-surface layer being crystallized after exposure to compression plasma flows is characterized by a homogeneous distribution of ele-ments and absence of pores formed in the process of coating formation. The coating structure is represented by a set of lar- ge (5–7 μm and small (1–2 μm zirconium oxide particles sintered against each other. Melting of coating surface layer and speed crystallization occur after the impact of compression plasma flows on the formed coating. Cracking of the surface layer arises due to origination of internal mechanical stresses in the crystallized part. While using a scanning electron microscopy a

  10. Methods of improvement in hardness of composite surface layer on cast steel

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2008-08-01

    Full Text Available The paper presents a method of usable properties of surface layers improvement of cast carbon steel 200–450, by put directly in founding process a composite surface layer on the basis of Fe-Cr-C alloy and next its remelting with use of welding technology TIG – Tungsten Inert Gas. Technology of composite surface layer guarantee mainly increase in hardness and abrasive wear resistance of cast steel castings on machine elements. This technology can be competition for generally applied welding technology (surfacing by welding and thermal spraying. However the results of studies show, that is possible to connection of both methods founding and welding of surface hardening of cast steel castings. In range of experimental plan was made test castings with composite surface layer, which next were remelted with energy 0,8 and 1,6 kJ/cm. Usability for industrial applications of test castings was estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.

  11. Evaluation of the surface structure of composite restorations in light of own pilot research

    Directory of Open Access Journals (Sweden)

    Chalas Renata

    2016-09-01

    Full Text Available Research on the dental restorative materials employed in remedying dental cavities has been conducted on many levels and areas, both with application of clinical and laboratory methods. One of the elements that determines whether the restoration may be degraded is the condition of its surface. The aim of the study was to assess the texture surface of composite restorations using a non-contact method of teeth models scanning. In this work, ten medium size cavities on the occlusal surfaces of molars in adult patients were prepared and restored with resin composite. Before undertaking the procedure and after the finishing and polishing of the restorations, impressions were taken and sent into the laboratory so as to prepare plaster casts. Every cast was then scanned utilizing the non-contact 3D surface measurement instrument so as to assess the texture surface of the restoration. The resulting three dimensional analyses of post-restoration models showed the correct marginal adaptation of resin composite dental material to the hard tooth structures and its smooth filling occlusal surface. Additional comparison of scans done before and after restoring the cavities allowed the calculating of differences in volume, mean and maximum heights. The applied method of analysis is thought to be helpful in the detailed evaluation of restoration dental material texture. Moreover, the enabled possibility of continuous observation is expedient for assessing the usefulness of the method in standard dental practice.

  12. Preliminary study of elemental composition in tree leaves for using as bio monitor for air pollution

    International Nuclear Information System (INIS)

    Chueinta, Wanna; Bunprapob, Supamatthree

    2004-10-01

    The use of plant tissue as biological monitor of air pollution has been of interest world wild. The study on chemical composition of such biological monitor may provide important information on the levels and pathways of a variety of pollutants including heavy metals and trace toxic elements in atmosphere. The appropriate bio monitors are such as herbaceous plants, tree leaves, bryophytes and lichens, with their possible advantages and/or limitations. In this research an investigation of element composition in leaves was performed. The technique of Instrument Neutron Activation Analysis (INAA) was developed to determine heavy metal and trace elements in 8 species of tree leaves collected from 3 different locations. From the experiments, it was found that content of elements might vary depending on species and environment. Some specific elements are discussed and compared in this report

  13. Major and trace elements in mouse bone measured by surface and bulk sensitive methods

    International Nuclear Information System (INIS)

    Benkoe, I.; Geresi, K.; Ungvari, E.; Szabo, B.; Paripas, B.

    2011-01-01

    Complete text of publication follows. In the past years an increasing research interest turned to the accurate determination of the components of bone samples. These investigations focused on both the major and trace elements in the bone. Work in this field is strongly motivated because various major and trace element concentrations can be good indicators of several diseases. Number of studies also focused on the determination of the components both in the organic and inorganic parts of the bone separately, because they both have role during bone remodeling processes. Also important to note that bone can be one of the final destinations in the body where toxic elements are deposited. In this work we performed various surface and bulk sensitive analyses for the mouse bone samples to determine its major and trace element components. We have shown concentration profiles for various major and observable trace elements of the mouse bone. We found, in accordance with our expectation, that the mostly surface sensitive XPS technique is not suitable to determine the concentration of the trace elements in bone samples. It was also shown that XPS is a valuable tool not only in the determination of the chemical states of the major components of the bone powder but in the quantitative determination of their relative concentrations. Both the major and the trace elements of the bone samples are determined using PIXE and SNMS spectra. Although the information depths are very different for PIXE (a few tens of micrometer) and for XPS analysis (a few nanometers), our present PIXE result, using the bone sample in its original form for the concentration ratio between Ca and P is in excellent agreement with the XPS results using calcinated mouse bone powder. Discrepancy in Ca/Mg ratio (PIXE: 35.7 and XPS: 12.7) maybe due to many factors, which influence this ratio in bone samples. In the case of PIXE we studied native bones and determined composition of the compact bone at outside

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

    Energy Technology Data Exchange (ETDEWEB)

    Bech, Niels; Jensen, Peter Arendt; Dam-Johansen, Kim [Department of Chemical and Biochemical Engineering, CHEC Research Centre, Technical University of Denmark, Soeltofts Plads, Building 229, DK-2800 Kongens Lyngby (Denmark)

    2009-03-15

    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 higher heating value. By analysing pure organic substances, literature data, and fuels it is demonstrated that the method can provide hydrogen estimates within {+-}0.7% daf. and carbon and sum of oxygen, nitrogen, and sulphur estimates within {+-}2% daf. for fuels containing less than 90% ash db., 2% nitrogen daf., and 1% daf. sulphur. (author)

  15. Surface discoloration of composite resins: Effects of staining and bleaching.

    Science.gov (United States)

    Poggio, Claudio; Beltrami, Riccardo; Scribante, Andrea; Colombo, Marco; Chiesa, Marco

    2012-09-01

    The purpose of this in vitro study was to evaluate surface discoloration of three microhybrid composite resins (Esthet•X HD, Clearfil AP-X, Gradia Direct) and five nanohybrid composite resins (Ceram•X, GC Kalore, G-aenial, Grandio, GrandioSO), after staining and bleaching procedures. The composite resins were polymerized with a curing light (Celalux II, Voco, Cuxhaven, Germany) into 160 silicon molds (6,4 mm in diameter and 2 mm in thickness) to obtain identical specimens. Twenty samples for each composite resin were prepared. The specimens were polished using an automated polishing machine with the sequence of 600-, 800-, 1000-grit abrasive paper under water irrigation. The specimens were immersed in tea and distilled water: the specimens were dipped for 20 min, once a day (every 24 h), for 14 days into the drinks. The specimens were then bleached with carbamide peroxide at 17% (Perfect Bleach-Voco). The color of specimens was measured with a spectrophotometer according to the CIE L(*)a(*)b(*) system after light-polymerization of composite resin specimens, after 7 days, after 14 days, and after bleaching. The color difference h index (DEab(*)) between each measurement was calculated. Statistical analysis was made using analysis of variance (ANOVA). All specimens showed a significant increase in staining with a similar trend and no significant differences between microhybrid and nanohybrid composite resins. After whitening procedures, materials tested showed both significant and unsignificant differences of the h index. Microhybrid and nanohybrid composite resins had similar in vitro surface discoloration in tea. After bleaching, discoloration was removed from some composite resins tested.

  16. Elastic representation surfaces of unidirectional graphite/epoxy composites

    International Nuclear Information System (INIS)

    Kriz, R.D.; Ledbetter, H.M.

    1985-01-01

    Unidirectional graphite/epoxy composites exhibit high elastic anisotropy and unusual geometrical features in their elastic-property polar diagrams. From the five-component transverse-isotropic elastic-stiffness tensor we compute and display representation surfaces for Young's modulus, torsional modulus, linear compressibility, and Poisson's ratios. Based on Christoffel-equation solutions, we describe some unusual elastic-wave-surface topological features. Musgrave considered in detail the differences between phase-velocity and group-velocity surfaces arising from high elastic anisotropy. For these composites, we find effects similar to, but more dramatic than, Musgrave's. Some new, unexpected results for graphite/epoxy include: a shear-wave velocity that exceeds a longitudinal velocity in the plane transverse to the fiber; a wave that changes polarization character from longitudinal to transverse as the propagation direction sweeps from the fiber axis to the perpendicular axis

  17. 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.

  18. Radioactive elements definition in composition of snake venom

    International Nuclear Information System (INIS)

    Mekhrabova, M.A.; Topchieva, Sh.F.; Abiev, G.A.; Nagiev, Dj.A.

    2010-11-01

    Full text: The given article presents questions concerned to usage of snake venom in medicine and pharmacy for medicinal drugs production, zootoxin base antidotes, thorough treatment of many deseases, especially onkological, also have a widespread in biology as a specific test-material for biological sistem analises. It is experimentally proved that certain amount of snake venom can replace morphine drugs, taking into acount that snake venom solutions make longer prolonged influence than other drugs, vithout causing an accustoming. It is also marked about possibility of usage of snake venom for cancer treatment. Many expeditions had been conducted with the purpose to research snake venom crytals on the territory of Azerbaijan. During these expeditions snakes capturing had been made with the purpose of taking the venom and also soil samples had been taken in order to research the quantity of radioactive elements. Measurements made with the help of electronic microscope C anberra . Revealed uranium activity in spectrum of venom as a result of radiation background, which appears under influence of ionizing radiation on the environment. On the base of analises data it can be ascertained that snake venom can be used for production of medicinal and also other necessary drugs. [ru

  19. Elemental composition of skin tissue by PIXE and INAA analyses

    International Nuclear Information System (INIS)

    Hollands, R.; Spyrou, N.M.

    1997-01-01

    Hypertrophic scars are a particular type of scar that can form after any type of dermal injury. They are unsightly, red, elevated above normal skin level, itchy and painful. At present no-one knows why these scars form. Due to the differences between scar tissue and normal skin it was decided to analyse skin tissue which at a later date would be compared to scar tissue. Spit skin graft (epidermis) samples as well as full thickness skin (epidermis to dermis) tissue were analysed using PIXE and RBS with a 2 MeV proton beam. The epidermis was compared to the dermis to see if there were any variations between the two. In all the samples P, S, Cl, K, Ca, Fe, and Cd were detected and in a majority of the samples Zn and Ba were found, using PIXE. It was found that, between the epidermis and dermis, there was an significant increase in P in the epidermis in both full thickness and split skin graft samples. Complementary elemental analysis was also performed using neutron activation, and Br, Na and Zn were detected. (author)

  20. Research of carbon composite material for nonlinear finite element method

    Science.gov (United States)

    Kim, Jung Ho; Garg, Mohit; Kim, Ji Hoon

    2012-04-01

    Works on the absorption of collision energy in the structural members are carried out widely with various material and cross-sections. And, with ever increasing safety concerns, they are presently applied in various fields including railroad trains, air crafts and automobiles. In addition to this, problem of lighting structural members became important subject by control of exhaust gas emission, fuel economy and energy efficiency. CFRP(Carbon Fiber Reinforced Plastics) usually is applying the two primary structural members because of different result each design parameter as like stacking thickness, stacking angle, moisture absorption ect. We have to secure the data for applying primary structural members. But it always happens to test design parameters each for securing the data. So, it has much more money and time. We can reduce the money and the time, if can ensure the CFRP material properties each design parameters. In this study, we experiment the coupon test each tension, compression and shear using CFRP prepreg sheet and simulate non-linear analyze at the sources - test result, Caron longitudinal modulus and matrix poisson's ratio using GENOAMQC is specialized at Composite analysis. And then we predict the result that specimen manufacture changing stacking angle and experiment in such a way of test method using GENOA-MCQ.

  1. Buckling Analysis of Single and Multi Delamination In Composite Beam Using Finite Element Method

    Science.gov (United States)

    Simanjorang, Hans Charles; Syamsudin, Hendri; Giri Suada, Muhammad

    2018-04-01

    Delamination is one type of imperfection in structure which found usually in the composite structure. Delamination may exist due to some factors namely in-service condition where the foreign objects hit the composite structure and creates inner defect and poor manufacturing that causes the initial imperfections. Composite structure is susceptible to the compressive loading. Compressive loading leads the instability phenomenon in the composite structure called buckling. The existence of delamination inside of the structure will cause reduction in buckling strength. This paper will explain the effect of delamination location to the buckling strength. The analysis will use the one-dimensional modelling approach using two- dimensional finite element method.

  2. Elemental composition analysis of stony meteorites discovered in Phitsanulok, Thailand

    Science.gov (United States)

    Loylip, T.; Wannawichian, S.

    2017-09-01

    A meteorite is a fragment of pure stone, iron or the mixture of stony-iron. The falling of meteorites into Earth’s surface is part of Earth’s accretion process from dust and rocks in our solar system. When these fragments come close enough to the Earth to be attracted by its gravity, they may fall into the Earth. Following the detection of objects that fall from the sky onto a home in Phitsanulok in June 27, the meteorites were analyzed by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS) instruments. The results from SEM/EDS analysis show that the meteorites are mainly composed of Fe-Ni and Fe-s. The meteorite is Achondrite, a class of meteorite which does not contain Chondrule. The meteorites in this work are thought to be part of a large asteroid.

  3. Effect of metal surface composition on deposition behavior of stainless steel component dissolved in liquid sodium

    International Nuclear Information System (INIS)

    Yokota, Norikatsu; Shimoyashiki, Shigehiro

    1988-01-01

    Deposition behavior of corrosion products has been investigated to clarify the effect of metal surface composition on the deposition process in liquid sodium. For the study a sodium loop made of Type 304 stainless steel was employed. Deposition test pieces, which were Type 304 stainless steel, iron, nickel or Inconel 718, were immersed in the sodium pool of the test pot. Corrosion test pieces, which were Type 304 stainless steel, 50 at% Fe-50 at%Mn and Inconel 718, were set in a heater pin assembly along the axial direction of the heater pin surface. Sodium temperatures at the outlet and inlet of the heater pin assembly were controlled at 943 and 833 K, respectively. Sodium was purified at a cold trap temperature of 393 K and the deposition test was carried out for 4.3 x 10 2 - 2.9 x 10 4 ks. Several crystallized particles were observed on the surface of the deposition test pieces. The particles had compositions and crystal structures which depended on both the composition of deposition test pieces and the concentration of iron and manganese in sodium. Only iron-rich particles having a polyhedral shape deposited on the iron surface. Two types of particles, iron-rich α-phase and γ-phase with nearly the same composition as stainless steel, were deposited on Type 304 stainless steel. A Ni-Mn alloy was deposited on the nickel surface in the case of a higher concentration of manganese in sodium. On the other hand, for a lower manganese concentration, a Fe-Ni alloy was precipitated on the nickel surface. Particles deposited on nickel had a γ-phase crystal structure similar to the deposition test piece of nickel. Hence, the deposition process can be explained as follows: Corrosion products in liquid sodium were deposited on the metal surface by forming a metal alloy selectively with elements of the metal surface. (author)

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

    International Nuclear Information System (INIS)

    Li Chaoliu; Kang Shichang; Zhang Qianggong

    2009-01-01

    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 μm 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.

  5. Multigrid Finite Element Method in Calculation of 3D Homogeneous and Composite Solids

    Directory of Open Access Journals (Sweden)

    A.D. Matveev

    2016-12-01

    Full Text Available In the present paper, a method of multigrid finite elements to calculate elastic three-dimensional homogeneous and composite solids under static loading has been suggested. The method has been developed based on the finite element method algorithms using homogeneous and composite three-dimensional multigrid finite elements (MFE. The procedures for construction of MFE of both rectangular parallelepiped and complex shapes have been shown. The advantages of MFE are that they take into account, following the rules of the microapproach, heterogeneous and microhomogeneous structures of the bodies, describe the three-dimensional stress-strain state (without any simplifying hypotheses in homogeneous and composite solids, as well as generate small dimensional discrete models and numerical solutions with a high accuracy.

  6. Determination of solid surface composition by the X-ray fluorescence method under total external reflection with angular scanning

    International Nuclear Information System (INIS)

    Krasnolutskij, V.P.

    2000-01-01

    Possibilities of determination of composition of surface layers by X-ray fluorescence analysis under total reflection of incident radiation with angular scanning of a target are investigated. For the case of the GaAs target it is shown that the sensibility of this method is sufficient for a control of element composition in layer of thickness 1 nm. A simple method for solution of inverse task of analysis of a two component medium is considered [ru

  7. The role of current characteristics of the arc evaporator in formation of the surface metal-coating composite

    International Nuclear Information System (INIS)

    Plikhunov, V V; Petrov, L M; Grigorovich, K V

    2016-01-01

    The influence of current characteristics of the vacuum arc evaporator on the interaction process of plasma streams with the surface under treatment during generation of the physicochemical properties of the formed metal-coating composite is considered. It is shown that the interaction of plasma streams with the processed surface provides surface heating, defects elimination, change in energy properties, and mass transfer of plasma stream elements activating surface diffusion processes whose intensity is evaluated by the arc current magnitude and location of the processed surface relative to the cathode axis. (paper)

  8. Environmental controls on the elemental composition of a Southern Hemisphere strain of the coccolithophore Emiliania huxleyi

    Directory of Open Access Journals (Sweden)

    Y. Feng

    2018-01-01

    Full Text Available A series of semi-continuous incubation experiments were conducted with the coccolithophore Emiliania huxleyi strain NIWA1108 (Southern Ocean isolate to examine the effects of five environmental drivers (nitrate and phosphate concentrations, irradiance, temperature, and partial pressure of CO2 (pCO2 on both the physiological rates and elemental composition of the coccolithophore. Here, we report the alteration of the elemental composition of E. huxleyi in response to the changes in these environmental drivers. A series of dose–response curves for the cellular elemental composition of E. huxleyi were fitted for each of the five drivers across an environmentally representative gradient. The importance of each driver in regulating the elemental composition of E. huxleyi was ranked using a semi-quantitative approach. The percentage variations in elemental composition arising from the change in each driver between present-day and model-projected conditions for the year 2100 were calculated. Temperature was the most important driver controlling both cellular particulate organic and inorganic carbon content, whereas nutrient concentrations were the most important regulator of cellular particulate nitrogen and phosphorus of E. huxleyi. In contrast, elevated pCO2 had the greatest influence on cellular particulate inorganic carbon to organic carbon ratio, resulting in a decrease in the ratio. Our results indicate that the different environmental drivers play specific roles in regulating the elemental composition of E. huxleyi with wide-reaching implications for coccolithophore-related marine biogeochemical cycles, as a consequence of the regulation of E. huxleyi physiological processes.

  9. Finite Element Analysis of Three-Dimensional (3D Auxetic Textile Composite under Compression

    Directory of Open Access Journals (Sweden)

    Jifang Zeng

    2018-03-01

    Full Text Available This paper reports a finite element (FE analysis of three-dimensional (3D auxetic textile composite by using commercial software ANSYS 15 under compression. The two-dimensional (2D FE model was first developed and validated by experiment. Then, the validated model was used to evaluate effects of structural parameters and constituent material properties. For the comparison, 3D non-auxetic composite that was made with the same constituent materials and structural parameters, but with different yarn arrangement in the textile structure was also analyzed at the same time. The analysis results showed that the auxetic and non-auxetic composites have different compression behaviors and the auxetic composite has better the energy absorption capacity than the non-auxetic composite under the same compression stress. The study has provided us a guidance to design and fabricate auxetic composites with the required mechanical behavior by appropriately selecting structural parameters and constituent materials.

  10. FINITE ELEMENT ANALYSIS OF TAPERED COMPOSITE PLATE GIRDER WITH A NON-LINEAR VARYING WEB DEPTH

    Directory of Open Access Journals (Sweden)

    Q. A. HASAN

    2017-11-01

    Full Text Available The paper presents Finite Element Analysis to determine the ultimate shear capacity of tapered composite plate girder. The effect of degree of taper on the ultimate shear capacity of tapered steel-concrete composite plate girder with a nonlinear varying web depth, effect of slenderness ratio on the ultimate shear capacity, and effect of flange stiffness on the ductility were considered as the parametric studies. Effect of concrete slab on the ultimate shear capacity of tapered plate girders was also considered and it was found to be so effective on the ultimate shear capacity of the tapered plate girder compared with the steel one. The accuracy of the finite element method is established by comparing the finite element with the results existing in the literature. The study was conducted using nonlinear finite element modelling with computer software LUSAS 14.7.

  11. Geochemical features of the elemental composition of meadowsweet (Filipendula ulmaria (L).Maxim) in Kemerovo Oblast

    Science.gov (United States)

    Zhdanov, V. A.; Sobolev, I. S.; Baranovskaya, N. V.; Kolesnikova, E. A.; Chernenkaya, E. V.; Yalaltdinova, A. R.

    2016-09-01

    Biogeochemical sampling of the aboveground part of meadowsweet (Fillipendula Ulmaria (L). Maxim) allowed us to study ecological and geochemical features of 10 regions in Kemerovo Oblast, including both natural and man-made landscapes. The content of 55 elements in the plant is determined by ICP-MS. Statistical analysis of the results allowed us to establish the effect of the soil mineral composition and the mining region specificity on the elemental composition of meadowsweet, to reveal significant positive correlations of the elements and to establish a statistically significant difference in the studied areas on the basis of the content of some elements. Sample reference to one of the clusters, followed by an assessment of their geochemical features is determined by the K-average method.

  12. Melting of the Primitive Mercurian Mantle, Insights into the Origin of Its Surface Composition

    Science.gov (United States)

    Boujibar, A.; Righter, K.; Rapp, J. F.; Ross, D. K.; Pando, K. M.; Danielson, L. R.; Fontaine, E.

    2016-01-01

    Recent findings of the MESSENGER mission on Mercury have brought new evidence for its reducing nature, widespread volcanism and surface compositional heteregeneity. MESSENGER also provided major elemental ratios of its surface that can be used to infer large-scale differentiation processes and the thermal history of the planet. Mercury is known as being very reduced, with very low Fe-content and high S and alkali contents on its surface. Its bulk composition is therefore likely close to EH enstatite chondrites. In order to elucidate the origin of the chemical diversity of Mercury's surface, we determined the melting properties of EH enstatite chondrites, at pressures between 1 bar and 3 GPa and oxygen fugacity of IW-3 to IW-5, using piston-cylinder experiments, combined with a previous study on EH4 melting at 1 bar. We found that the presence of Ca-rich sulfide melts induces significant decrease of Ca-content in silicate melts at low pressure and low degree of melting (F). Also at pressures lower than 3 GPa, the SiO2-content decreases with F, while it increases at 3 GPa. This is likely due to the chemical composition of the bulk silicate which has a (Mg+Fe+Ca)/Si ratio very close to 1 and to the change from incongruent to congruent melting of enstatite. We then tested whether the various chemical compositions of Mercury's surface can result from mixing between two melting products of EH chondrites. We found that the majority of the geochemical provinces of Mercury's surface can be explained by mixing of two melts, with the exception of the High-Al plains that require an Al-rich source. Our findings indicate that Mercury's surface could have been produced by polybaric melting of a relatively primitive mantle.

  13. Elemental composition of 'normal' and Alzheimer brain tissue by INA and PIXE analyses

    International Nuclear Information System (INIS)

    Stedman, J.D.; Spyrou, N.M.

    1997-01-01

    Instrumental methods based on the nuclear and atomic properties of the elements have been used for many years to determine elemental concentrations in a variety of materials for biomedical, industrial and environmental applications. These methods offer high sensitivity for accurate trace element measurements, suffer few interfering or competing effects. Present no blank problems and are convenient for both research and routine analyses. The present article describes the use of two trace element techniques. Firstly the use of activation of stable nuclei irradiated by neutrons in the core of a low power research reactor as a means of detection of elements through the resulting gamma-rays emitted. Secondly, the observations of the interactions of energetic ion beams with the material in order to identify elemental species. Over recent years there has been some interest in determining the elemental composition of 'normal' and Alzheimer affected brain tissue, however literature findings are inconsistent. Possible reasons for discrepancies need to be identified for further progress to be made. Here, post-mortem tissue samples, provided by the Alzheimer's Disease Brain Bank, Institute of Psychiatry, London, were taken from the frontal, occipital, parietal and temporal lobes of both hemispheres of brains from 13 'normal' and 19 Alzheimer subjects. The elemental composition of the samples was determined using the analytical techniques of INAA (instrumental neutron activation analysis), RBS (Rutherford back-scattering) and PIXE (particle induced x-ray emission). The principal findings are summarised here. (author)

  14. Characteristics of element composition of aerosols adsorbed on leaves by radioactivation analysis and their effects on plants

    International Nuclear Information System (INIS)

    Takamatsu, Takejiro; Koshikawa, Masami; 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.)

  15. Investigation of sizing - from glass fibre surface to composite interface

    DEFF Research Database (Denmark)

    Petersen, Helga Nørgaard; Kusano, Yukihiro

    significantly. The usage span wide, from furniture and car components to construction materials. Even though, the concept of composites is well known and widely applied, the fundamental principles of the interaction of the constituents, in the composites are still not fully understood. This thesis is a part...... of the sizing from the glass fibre surface to the interface in composites. Through soxhlet extraction with acetone it was possible to remove a part of the sizing from the glass fibres for analysis. By burning off the sizing at 565 ºC a higher mass loss was obtained than from the extraction, indicating...... increased after the removal of sizing by extraction but also when the sizing was removed by burning. This could partly be explained by the sizing being less dense than the glass fibres. For the burned glass fibres compactment of the glass structure also yields an increase in stiffness. The fibre strength...

  16. Theory of the particle matrix elements for Helium atom scattering in surfaces

    International Nuclear Information System (INIS)

    Khater, A.; Toennies, J.P.

    2000-01-01

    Full text.A brief review is presented for the recent development of the theory of the particle transition matrix elements, basic to the cross section for Helium and inert particle scattering at thermal energies in solid surfaces. the Jackson and Mott matrix elements are presented and discussed for surface scattering processes, habitually classified as elastic and inelastic. Modified transition matrix elements, introduced originally to account for the cut-off effects, are presented in a direct and simple manner. the Debye-Waller factor is introduced and discussed. A recent calculation for the particle transition matrix elements is presented for the specular and inelastic transition matrix elements and the corresponding inelastic scattering cross section is compared in detail to experimental data. the specular and inelastic transition matrix elements are found to be intrinsically similar owing to the intermediate role of a proposed virtual particle squeezed state near the surface

  17. 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.

  18. Composite beryllium-ceramics breeder pin elements for a gas cooled solid blanket

    International Nuclear Information System (INIS)

    Carre, F.; Chevreau, G.; Gervaise, F.; Proust, E.

    1986-06-01

    Helium coolant have main advantages compared to water for solid blankets. But limitations exist too and the development of attractive helium cooled blankets based on breeder pin assemblies has been essentially made possible by the derivation from recent CEA neutronic studies of an optimized composite beryllium/ceramics breeder arrangement. Description of the proposed toroidal blanket layout for Net is made together with the analysis of its main performance. Merits of the considered composite Be/ceramics breeder elements are discussed

  19. Finite element simulation of a novel composite light-weight microporous cladding panel

    Science.gov (United States)

    Tian, Lida; Wang, Dongyan

    2018-04-01

    A novel composite light-weight microporous cladding panel with matched connection detailing is developed. Numerical simulation on the experiment is conducted by ABAQUS. The accuracy and rationality of the finite element model is verified by comparison between the simulation and the experiment results. It is also indicated that the novel composite cladding panel is of desirable bearing capacity, stiffness and deformability under out-of-plane load.

  20. 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.

  1. Nonlinear finite element modeling of concrete deep beams with openings strengthened with externally-bonded composites

    International Nuclear Information System (INIS)

    Hawileh, Rami A.; El-Maaddawy, Tamer A.; Naser, Mohannad Z.

    2012-01-01

    Highlights: ► A 3D nonlinear FE model is developed of RC deep beams with web openings. ► We used cohesion elements to simulate bond. ► The developed FE model is suitable for analysis of such complex structures. -- Abstract: This paper aims to develop 3D nonlinear finite element (FE) models for reinforced concrete (RC) deep beams containing web openings and strengthened in shear with carbon fiber reinforced polymer (CFRP) composite sheets. The web openings interrupted the natural load path either fully or partially. The FE models adopted realistic materials constitutive laws that account for the nonlinear behavior of materials. In the FE models, solid elements for concrete, multi-layer shell elements for CFRP and link elements for steel reinforcement were used to simulate the physical models. Special interface elements were implemented in the FE models to simulate the interfacial bond behavior between the concrete and CFRP composites. A comparison between the FE results and experimental data published in the literature demonstrated the validity of the computational models in capturing the structural response for both unstrengthened and CFRP-strengthened deep beams with openings. The developed FE models can serve as a numerical platform for performance prediction of RC deep beams with openings strengthened in shear with CFRP composites.

  2. Formation, Phase, and Elemental Composition of Micro- and Nano-Dimensional Particles of the Fe-Ti System

    Science.gov (United States)

    Dresvyannikov, A. F.; Kolpakov, M. E.

    2018-05-01

    X-ray fluorescence, X-ray phase analysis, and transmission Mössbauer and NGR spectrometry are used to study the formation, phase, and elemental composition of Fe-Ti particles. The interaction between Fe(III) ions and dispersed titanium in an aqueous solution containing chloride ions and HF is studied. It is shown that the resulting Fe-Ti samples are a set of core-shell microparticles with titanium cores coated with micro- and nanosized α-Fe nucleation centers with the thinness outer layer of iron(III) oxide characterized by a developed surface.

  3. Kenaf-polypropylene composites: effect of amphiphilic coupling agent on surface properties of fibres and composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2010-10-01

    Full Text Available This paper presents an experimental study on the use of zein as a coupling agent in natural fibre composites. Kenaf nonwovens were treated with zein coupling agent, which is a protein extracted from corn. The surface characteristics of untreated...

  4. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    Science.gov (United States)

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H 2 SO 4 and CaCl 2 . Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H 2 SO 4 and CaCl 2 ; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Experimental Investigation and Discrete Element Modelling of Composite Hollow Spheres Subjected to Dynamic Fracture

    Directory of Open Access Journals (Sweden)

    Arthur Coré

    2017-01-01

    Full Text Available This paper deals with the characterization and the numerical modelling of the collapse of composite hollow spherical structures developed to absorb energy during high velocity impacts. The structure is composed of hollow spheres (ϕ=2–30 mm made of epoxy resin and mineral powder. First of all, quasi-static and dynamic (v=5 mm·min−1 to v=2 m·s−1 compression tests are conducted at room temperature on a single sphere to study energy dissipation mechanisms. Fracture of the material appears to be predominant. A numerical model based on the discrete element method is investigated to simulate the single sphere crushing. The stress-strain-time relationship of the material based on the Ree-Eyring law is numerically implemented. The DEM modelling takes naturally into account the dynamic fracture and the crack path computed is close to the one observed experimentally in uniaxial compression. Eventually, high velocity impacts (v>100 m·s−1 of a hollow sphere on a rigid surface are conducted with an air cannon. The numerical results are in good agreement with the experimental data and demonstrate the ability of the present model to correctly describe the mechanical behavior of brittle materials at high strain rate.

  6. Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

    International Nuclear Information System (INIS)

    Fatchurrohman, N; Marini, C D; Suraya, S; Iqbal, AKM Asif

    2016-01-01

    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. (paper)

  7. 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.

  8. The effect of different aluminum alloy surface compositions on barrier anodic film formation

    International Nuclear Information System (INIS)

    Panitz, J.K.G.; Sharp, D.J.

    1984-01-01

    The authors have grown barrier anodic coatings on samples of aluminum alloy with different elemental surface compositions. In one series of experiments, they characterized the surface composition present on 6061 aluminum alloy samples after different chemical treatments including a detergent-water and methyl-ethyl ketone solvent clean, a 50% nitric acid-water etch, and a concentrated nitric acid-ammonium bifluoride etch. They anodized samples which were prepared similarly to those analyzed to evaluate the practical effects of the three different surface compositions. The anodization voltage rise time to 950V at constant current was used as a figure of merit. The solvent cleaned and the 50% nitric acid etched samples required, respectively, 113% and 41% more time to reach 950V than the concentrated nitric acidammonium bifloride etched samples. In a second series of experiments, they alternately anodized groups of either 6061 or 1100 (commercially pure) aluminum alloy, observed rise times to 950V, and measured chloride ion concentrations in the electrolyte. Longer rise times and higher chloride ion concentrations were observed for the 1100 samples. It was observed that the chloride ion concentration fell from initially high levels when 6061 samples were anodized. The results of both series of experiments augment the results of other investigators, who report that the surface species initially present on aluminum have a significant effect on anodic film formation

  9. Determination of elemental tissue composition following proton treatment using positron emission tomography

    International Nuclear Information System (INIS)

    Cho, Jongmin; Ibbott, Geoffrey; Gillin, Michael; Gonzalez-Lepera, Carlos; Min, Chul Hee; Zhu, Xuping; El Fakhri, Georges; Paganetti, Harald; Mawlawi, Osama

    2013-01-01

    Positron emission tomography (PET) has been suggested as an imaging technique for in vivo proton dose and range verification after proton induced-tissue activation. During proton treatment, irradiated tissue is activated and decays while emitting positrons. In this paper, we assessed the feasibility of using PET imaging after proton treatment to determine tissue elemental composition by evaluating the resultant composite decay curve of activated tissue. A phantom consisting of sections composed of different combinations of 1 H, 12 C, 14 N, and 16 O was irradiated using a pristine Bragg peak and a 6 cm spread-out Bragg-peak (SOBP) proton beam. The beam ranges defined at 90% distal dose were 10 cm; the delivered dose was 1.6 Gy for the near monoenergetic beam and 2 Gy for the SOBP beam. After irradiation, activated phantom decay was measured using an in-room PET scanner for 30 min in list mode. Decay curves from the activated 12 C and 16 O sections were first decomposed into multiple simple exponential decay curves, each curve corresponding to a constituent radioisotope, using a least-squares method. The relative radioisotope fractions from each section were determined. These fractions were used to guide the decay curve decomposition from the section consisting mainly of 12 C + 16 O and calculate the relative elemental composition of 12 C and 16 O. A Monte Carlo simulation was also used to determine the elemental composition of the 12 C + 16 O section. The calculated compositions of the 12 C + 16 O section using both approaches (PET and Monte Carlo) were compared with the true known phantom composition. Finally, two patients were imaged using an in-room PET scanner after proton therapy of the head. Their PET data and the technique described above were used to construct elemental composition ( 12 C and 16 O) maps that corresponded to the proton-activated regions. We compared the 12 C and 16 O compositions of seven ROIs that corresponded to the vitreous humor, adipose

  10. Trace elements in the sea surface microlayer: rapid responses to changes in aerosol deposition

    Directory of Open Access Journals (Sweden)

    Alina M. Ebling

    2017-08-01

    Full Text Available Natural and anthropogenic aerosols are a significant source of trace elements to oligotrophic ocean surface waters, where they provide episodic pulses of limiting micronutrients for the microbial community. However, little is known about the fate of trace elements at the air-sea interface, i.e. the sea surface microlayer. In this study, samples of aerosols, sea surface microlayer, and underlying water column were collected in the Florida Keys during a dusty season (July 2014 and non-dusty season (May 2015 and analyzed for the dissolved and particulate elements Al, Fe, Ni, Cu, Zn, and Pb. Microlayer samples were collected using a cylinder of ultra-pure SiO2 (quartz glass, a novel adaptation of the glass plate technique. A significant dust deposition event occurred during the 2014 sampling period which resulted in elevated concentrations of trace elements in the microlayer. Residence times in the microlayer from this event ranged from 12 to 94 minutes for dissolved trace elements and from 1.3 to 3.4 minutes for particulate trace elements. These residence times are potentially long enough for the atmospherically derived trace elements to undergo chemical and biological alterations within the microlayer. Characterizing the trace element distributions within the three regimes is an important step towards our overall goals of understanding the rates and mechanisms of the solubilization of trace elements following aeolian dust deposition and how this might affect microorganisms in surface waters.

  11. Titan's Surface Composition from Cassini VIMS Solar Occultation Observations

    Science.gov (United States)

    McCord, Thomas; Hayne, Paul; Sotin, Christophe

    2013-04-01

    Titan's surface is obscured by a thick absorbing and scattering atmosphere, allowing direct observation of the surface within only a few spectral win-dows in the near-infrared, complicating efforts to identify and map geologi-cally important materials using remote sensing IR spectroscopy. We there-fore investigate the atmosphere's infrared transmission with direct measure-ments using Titan's occultation of the Sun as well as Titan's reflectance measured at differing illumination and observation angles observed by Cas-sini's Visual and Infrared Mapping Spectrometer (VIMS). We use two im-portant spectral windows: the 2.7-2.8-mm "double window" and the broad 5-mm window. By estimating atmospheric attenuation within these windows, we seek an empirical correction factor that can be applied to VIMS meas-urements to estimate the true surface reflectance and map inferred composi-tional variations. Applying the empirical corrections, we correct the VIMS data for the viewing geometry-dependent atmospheric effects to derive the 5-µm reflectance and 2.8/2.7-µm reflectance ratio. We then compare the cor-rected reflectances to compounds proposed to exist on Titan's surface. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scattering in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass water ice for the majority of the low-to-mid latitude area covered by VIMS measurements. Four compositional units are defined and mapped on Titan's surface based on the positions of data clusters in 5-mm vs. 2.8/2.7-mm scatter plots; a simple ternary mixture of H2O, hydrocarbons and CO2 might explain the reflectance properties of these surface units. The vast equatorial "dune seas" are compositionally very homogeneous, perhaps suggesting transport and mixing of particles over very large distances and/or and very consistent formation process and source material. The composi-tional branch characterizing Tui Regio and Hotei Regio is

  12. Piezoelectric composite morphing control surfaces for unmanned aerial vehicles

    Science.gov (United States)

    Ohanian, Osgar J., III; Karni, Etan D.; Olien, Chris C.; Gustafson, Eric A.; Kochersberger, Kevin B.; Gelhausen, Paul A.; Brown, Bridget L.

    2011-04-01

    The authors have explored the use of morphing control surfaces to replace traditional servo-actuated control surfaces in UAV applications. The morphing actuation is accomplished using Macro Fiber Composite (MFC) piezoelectric actuators in a bimorph configuration to deflect the aft section of a control surface cross section. The resulting camber change produces forces and moments for vehicle control. The flexible piezoelectric actuators are damage tolerant and provide excellent bandwidth. The large amplitude morphing deflections attained in bench-top experiments demonstrate the potential for excellent control authority. Aerodynamic performance calculations using experimentally measured morphed geometries indicate changes in sectional lift coefficients that are superior to a servo-actuated hinged flap airfoil. This morphing flight control actuation technology could eliminate the need for servos and mechanical linkages in small UAVs and thereby increase reliability and reduce drag.

  13. The effect of simulating porcelain firing on the elemental composition, microstructure, and mechanical properties of electroformed gold restorations

    Directory of Open Access Journals (Sweden)

    Youssef S. Al Jabbari

    2016-09-01

    Conclusion: Although microstructure and elemental composition of electroformed Au crowns remain unchanged, the mechanical properties are significantly affected by the thermal treatment of porcelain firing.

  14. Size Resolved Mass Concentration and Elemental Composition of Atmospheric Aerosols over the Eastern Mediterranean Area

    Czech Academy of Sciences Publication Activity Database

    Smolík, Jiří; Ždímal, Vladimír; Schwarz, Jaroslav; Lazaridis, M.; Havránek, Vladimír; Eleftheriadis, K.; Mihalopoulos, N.; Bryant, C.; Colbeck, I.

    2003-01-01

    Roč. 3, - (2003), s. 2207-2216 ISSN 1680-7324 Grant - others:ENVK2(XE) 1999/00052 Institutional research plan: CEZ:AV0Z1048901; CEZ:AV0Z4072921 Keywords : atmospheric particles * elemental composition * PM1 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.317, year: 2003

  15. Size Resolved Mass Concentration and Elemental Composition of Atmospheric Aerosols over the Eastern Mediterranean Area

    Czech Academy of Sciences Publication Activity Database

    Smolík, Jiří; Ždímal, Vladimír; Schwarz, Jaroslav; Lazaridis, M.; Havránek, Vladimír; Eleftheriadis, K.; Mihalopoulos, N.; Bryant, C.; Colbeck, I.

    2003-01-01

    Roč. 3, - (2003), s. 2547-2573 ISSN 1680-7367 Grant - others:ENVK2(XE) 1999/00052 Institutional research plan: CEZ:AV0Z1048901; CEZ:AV0Z4072921 Keywords : atmospheric particles * PM1 * elemental composition Subject RIV: CF - Physical ; Theoretical Chemistry

  16. Finite element simulations and experiments of ballistic impacts on high performance PE composite material

    NARCIS (Netherlands)

    Herlaar, K.; Jagt-Deutekom, M.J. van der; Jacobs, M.J.N.

    2005-01-01

    The use of lightweight composite armour concepts is essential for the protection of future combat systems, both vehicles and personal. The design of such armour systems is challenging due to the complex material behaviour. Finite element simulations can be used to help understand the important

  17. Effect of storage on the yield and the elemental composition of the ...

    African Journals Online (AJOL)

    The yield of the volatile oils of Eucalyptus citrodora and lemon grass obtained from a locally constructed apparatus is presented. Hydro distillation of the fresh and dried leaves at room temperature (25°C) gave a better yield with dried leaves. Elemental composition of the crude and rectified volatile oils of the predominant ...

  18. Development of an anisotropic beam finite element for composite wind turbine blades in multibody system

    DEFF Research Database (Denmark)

    Kim, Taeseong; Hansen, Anders Melchior; Branner, Kim

    2013-01-01

    In this paper a new anisotropic beam finite element for composite wind turbine blades is developed and implemented into the aeroelastic nonlinear multibody code, HAWC2, intended to be used to investigate if use of anisotropic material layups in wind turbine blades can be tailored for improved...

  19. 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.

  20. Elemental composition of airborne dust in the shale shaker house during an offshore drilling operation

    DEFF Research Database (Denmark)

    Hansen, A.B.; Larsen, E.; Hansen, L.V.

    1991-01-01

    chrome lignosulphonate and chrome lignite, was circulated between the borehole and the Shale Shaker House. The concentration of airborne dust in the atmosphere was determined and the elemental composition of the particles analysed by both PIXE (proton-induced X-ray emission) and ICP-MS (inductively...

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

    CSIR Research Space (South Africa)

    Ndimba, R

    2015-09-01

    Full Text Available Instruments and Methods in Physics Research B 363 (2015) 183–187 Detecting changes in the nutritional value and elemental composition of transgenic sorghum grain R. Ndimba a,c,, A.W. Grootboom b, L. Mehlo b, N.L. Mkhonza b, J. Kossmann c, A...

  2. 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 of t...

  3. Ion beam effects on the surface and near-surface composition of TaSi sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Valeri, S.; Di Bona, A.; Ottaviani, G. (Dipt. di Fisica, Univ. di Modena (Italy)); Procop, M. (Zentralinstitut fuer Elektronenphysik, Berlin (Germany))

    1991-07-01

    Low-energy (0.7-4.5 keV) ion bombardment effects on polycrystalline TaSi{sub 2} at sputter steady state and in various intermediate steps have been investigated, in the temperature range up to 550degC, to determine the time and temperature dependence of the altered layer formation. This in turn enables a better knowledge of the synergistic effects of the processes mentioned above. At low temperatures (T{<=}410degC) the surface is silicon depleted, and the depletion is even more severe in the subsurface region up to a depth of several tens of angstroems; silicon preferential sputtering and radiation-enhanced segregation assisted by the displacement mixing-induced motion of atoms are assumed to be responsible for this composition profile, while thermally activated diffusion processes become operative above 410degC, reducing progressively the concentration gradient between the surface and the subsurface zone. The composition at different depths has been determined from Auger peaks for different kinetic energies, by varying the take-off angle and finally by sputter profiling at low in energy the high energy processed surfaces. Quantitative analysis has been performed by XPS and AES by using the elemental standard method. (orig.).

  4. The control mechanism of surface traps on surface charge behavior in alumina-filled epoxy composites

    International Nuclear Information System (INIS)

    Li, Chuanyang; Hu, Jun; Lin, Chuanjie; He, Jinliang

    2016-01-01

    To investigate the role surface traps play in the charge injection and transfer behavior of alumina-filled epoxy composites, surface traps with different trap levels are introduced by different surface modification methods which include dielectric barrier discharges plasma, direct fluorination, and Cr 2 O 3 coating. The resulting surface physicochemical characteristics of experimental samples were observed using atomic force microscopy, scanning electron microscopy and fourier transform infrared spectroscopy. The surface potential under dc voltage was detected and the trap level distribution was measured. The results suggest that the surface morphology of the experimental samples differs dramatically after treatment with different surface modification methods. Different surface trap distributions directly determine the charge injection and transfer property along the surface. Shallow traps with trap level of 1.03–1.11 eV and 1.06–1.13 eV introduced by plasma and fluorination modifications are conducive for charge transport along the insulating surface, and the surface potential can be modified, producing a smoother potential curve. The Cr 2 O 3 coating can introduce a large number of deep traps with energy levels ranging from 1.09 to 1.15 eV. These can prevent charge injection through the reversed electric field formed by intensive trapped charges in the Cr 2 O 3 coatings. (paper)

  5. Laser Surface Treatment and Modification of Aluminum Alloy Matrix Composites

    Science.gov (United States)

    Abbass, Muna Khethier

    2018-02-01

    The present work aimed to study the laser surface treatment and modification of Al-4.0%Cu-1.0%Mg alloy matrix composite reinforced with 10%SiC particles produced by stir casting. The specimens of the base alloy and composite were irradiated with an Nd:YAG laser of 1000 mJ, 1064 nm and 3 Hz . Dry wear test using the pin-on -disc technique at different sliding times (5-30 min) at a constant applied load and sliding speed were performed before and after laser treatment. Micro hardness and wear resistance were increased for all samples after laser hardening treatment. The improvement of these properties is explained by microstructural homogenization and grain refinement of the laser treated surface. Modification and refinement of SiC particles and grain refinement in the microstructure of the aluminum alloy matrix (α-Al) were observed by optical and SEM micrographs. The highest increase in hardness was 21.4% and 26.2% for the base alloy and composite sample respectively.

  6. 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.

  7. Mass composition studies using the surface detector of the Pierre Auger Observatory

    International Nuclear Information System (INIS)

    Wahlberg, Hernan

    2009-01-01

    The mass composition of ultra-high energy cosmic rays is a critical issue to understand their origin and nature. The Pierre Auger Observatory is a hybrid instrument which provides a powerful environment for the determination of the primary mass. The Surface Detector of the Pierre Auger Observatory alone allows the study of several shower parameters with high discriminating power between primary elements. Novel analysis techniques using different features of signals in the Cherenkov stations are discussed. These are the signal risetime, the azimuthal time asymmetry and the muon density of the showers.

  8. 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

  9. A Three End-Member Mixing Model Based on Isotopic Composition and Elemental Ratio

    Directory of Open Access Journals (Sweden)

    Kon-Kee Liu Shuh-Ji Kao

    2007-01-01

    Full Text Available A three end-member mixing model based on nitrogen isotopic composition and organic carbon to nitrogen ratio of suspended particulate matter in an aquatic environment has been developed. Mathematical expressions have been derived for the calculation of the fractions of nitrogen or organic carbon originating from three different sources of distinct isotopic and elemental compositions. The model was successfully applied to determine the contributions from anthropogenic wastes, soils and bedrock-derived sediments to particulate nitrogen and particulate organic carbon in the Danshuei River during the flood caused by Typhoon Bilis in August 2000. The model solutions have been expressed in a general form that allows applications to mixtures with other types of isotopic compositions and elemental ratios or in forms other than suspended particulate matter.

  10. Stability analysis of internally damped rotating composite shafts using a finite element formulation

    Science.gov (United States)

    Ben Arab, Safa; Rodrigues, José Dias; Bouaziz, Slim; Haddar, Mohamed

    2018-04-01

    This paper deals with the stability analysis of internally damped rotating composite shafts. An Euler-Bernoulli shaft finite element formulation based on Equivalent Single Layer Theory (ESLT), including the hysteretic internal damping of composite material and transverse shear effects, is introduced and then used to evaluate the influence of various parameters: stacking sequences, fiber orientations and bearing properties on natural frequencies, critical speeds, and instability thresholds. The obtained results are compared with those available in the literature using different theories. The agreement in the obtained results show that the developed Euler-Bernoulli finite element based on ESLT including hysteretic internal damping and shear transverse effects can be effectively used for the stability analysis of internally damped rotating composite shafts. Furthermore, the results revealed that rotor stability is sensitive to the laminate parameters and to the properties of the bearings.

  11. FORMATION AND RESEARCH OF MULTI-LAYER COMPOSITE PLASMA OXIDE COATINGS BASED ON ELEMENTS OF SCREEN METEROID PTOTECTION

    Directory of Open Access Journals (Sweden)

    V. A. Okovity

    2016-01-01

    Full Text Available The paper presents results of research for influence of plasma jet parameters (current, spraying distance, plasmasupporting nitrogen gas consumption, fractional composition of an initial powder and cooling degree by compressed air on characteristics of anti-meteorite coatings, subsequent processing modes by pulsed plasma. Properties of the obtained coatings and results of ballistic tests have been given in the paper. The proposed methodology has been based on complex metallographic, X-ray diffraction and electron microscopic investigations of anti-meteorite aluminum oxide coating. Optimization of air plasma spraying parameters for NiAl and Al2O3 materials has been carried out in the paper. The spraying parameters optimization has been executed on the basis of obtaining maximum materials utilization factor. Surface treatment of model screen elements with a double-layer composite coating (adhesive metal NiAl layer and hard ceramic oxide Al2O3 layer has been fulfilled while using compression plasma stream. Nitrogen has been used as working gas. Composite hard ceramic oxide Al2O3 coating is represented by porous structure consisting of 10–15 µm-size fused Al2O3 particles. Metallic inclusions formed due to erosion of plasmatron electrodes have been observed in the space between the particles. Surface of bilayer composite coatings has been processed by a compression plasma stream and due to nonsteady processes of melting and recrystallization high strength polycrystalline layer has been formed on their surface. In this context, those areas of the polycrystalline layer which had metal inclusions have appeared to be painted in various colors depending on chemical composition of the inclusions.

  12. The General Laws of Chemical Elements Composition Dynamics in the Biosphere

    Science.gov (United States)

    Korzh, Vyacheslav D.

    2013-04-01

    The key point of investigation of the specificity of the biosphere elemental composition formation is determination of patterns of redistribution of elemental average concentrations among various phases, like solid - liquid ( the lithosphere - the hydrosphere), which occurs as a result of a global continuous processing of inert matter by living substances. Our task here is to investigate this process in the system "lithosphere - hydrosphere" in view of the integrated involvement of living material in it. This process is most active in biogeochemical barriers, i.e. in places of "the life condensation" and runs under a nonlinear regularity that has been unknown before. It is established that this process results in a general relative increase in concentrations of chemical elements in the solid phase in proportion as their prevalence in the environment is reduced. This process running in various natural systems has practically the same parameter of nonlinearity (v) approximately equal to 0.7. For proto-lithosphere -"living material" - soil v = 0.75. For river - "living material" - ocean v = 0.67. For the contemporary factual awareness level these estimations of nonlinearity indices are practically negligible. Hence, it is for the first time that the existence of a universal constant of nonlinearity of elemental composition evolution in the biosphere has been proved and its quantitative evaluation has been made. REFERENCES 1. Korzh V.D. 1974. Some general laws governing the turnover of substance within the ocean-atmosphere-continent-ocean cycle. // Journal de Recherches Atmospheriques. Vol. 8. P. 653-660. 2. Korzh V.D. 2008. The general laws in the formation of the elemental composition of the Hydrosphere and Biosphere.// J. Ecologica, Vol. XV, P. 13-21. 3. Korzh V.D. 2012. Determination of general laws of elemental composition in Hydrosphere // Water: chemistry & ecology, Journal of water science and its practical application. # 1, P.56-62.

  13. Neutron radiography of aircraft composite flight control surfaces

    International Nuclear Information System (INIS)

    Lewis, W.J.; Bennett, L.G.I.; Chalovich, T.R.; Francescone, O.

    2001-01-01

    A small (20 kWth), safe, pool-type nuclear research reactor called the SLOWPOKE-2 is located at the Royal Military College of Canada (RMC). The reactor was originally installed for teaching, training, research and semi-routine analysis, specifically, neutron activation analysis. It was envisioned that the neutrons from the SLOWPOKE-2 could also be used for neutron radiography, and so a research program was initiated to develop this technology. Over a period of approximately 15 years, and through a series of successive modifications, a neutron radiography system (NRS) was developed. Once completed, several applications of the technology have been demonstrated, including the nondestructive examination of the composite flight control surfaces from the Canadian Air Force's primary jet fighter, the CF18 Hornet aircraft. An initial trial was setup to investigate the flight control surfaces of 3 aircraft, to determine the parameters for a final licensed system, and to compare the results to other nondestructive methods. Over 500 neutron radiographs were made for these first 3 aircraft, and moisture and corrosion were discovered in the honeycomb structure and hydration was found in the composite and adhesive layers. In comparison with other NDT methods, neutron radiography was the only method that could detect the small areas of corrosion and moisture entrapment. However, before examining an additional 7 aircraft, the recommended modifications to the NRS were undertaken. These modifications were necessary to accommodate the larger flight control surfaces safely by incorporating flexible conformable shielding. As well, to expedite inspections so that all flight control surfaces from one aircraft could be completed in less than two weeks, there was a need to decrease the exposure time by both faster film/conversion screen combinations and by incorporating the capability of near realtime, digital radioscopy. Finally, as there are no inspection specific image quality

  14. Surface composition of biomedical components by ion beam analysis

    International Nuclear Information System (INIS)

    Kenny, M.J.; Wielunski, L.S.; Baxter, G.R.

    1991-01-01

    Materials used for replacement body parts must satisfy a number of requirements such as biocompatibility and mechanical ability to handle the task with regard to strength, wear and durability. When using a CVD coated carbon fibre reinforced carbon ball, the surface must be ion implanted with uniform dose of nitrogen ions in order to make it wear resistant. The mechanism by which the wear resistance is improved is one of radiation damage and the required dose of about 10 16 cm -2 can have a tolerance of about 20%. To implant a spherical surface requires manipulation of the sample within the beam and control system (either computer or manually operated) to enable uniform dose all the way from polar to equatorial regions on the surface. A manipulator has been designed and built for this purpose. In order to establish whether the dose is uniform, nuclear reaction analysis using the reaction 14 N(d,α) 12 C is an ideal method of profiling. By taking measurements at a number of points on the surface, the uniformity of nitrogen dose can be ascertained. It is concluded that both Rutherford Backscattering and Nuclear Reaction Analysis can be used for rapid analysis of surface composition of carbon based materials used for replacement body components. 2 refs., 2 figs

  15. Venus Surface Composition Constrained by Observation and Experiment

    Science.gov (United States)

    Gilmore, Martha; Treiman, Allan; Helbert, Jörn; Smrekar, Suzanne

    2017-11-01

    New observations from the Venus Express spacecraft as well as theoretical and experimental investigation of Venus analogue materials have advanced our understanding of the petrology of Venus melts and the mineralogy of rocks on the surface. The VIRTIS instrument aboard Venus Express provided a map of the southern hemisphere of Venus at ˜1 μm allowing, for the first time, the definition of surface units in terms of their 1 μm emissivity and derived mineralogy. Tessera terrain has lower emissivity than the presumably basaltic plains, consistent with a more silica-rich or felsic mineralogy. Thermodynamic modeling and experimental production of melts with Venera and Vega starting compositions predict derivative melts that range from mafic to felsic. Large volumes of felsic melts require water and may link the formation of tesserae to the presence of a Venus ocean. Low emissivity rocks may also be produced by atmosphere-surface weathering reactions unlike those seen presently. High 1 μm emissivity values correlate to stratigraphically recent flows and have been used with theoretical and experimental predictions of basalt weathering to identify regions of recent volcanism. The timescale of this volcanism is currently constrained by the weathering of magnetite (higher emissivity) in fresh basalts to hematite (lower emissivity) in Venus' oxidizing environment. Recent volcanism is corroborated by transient thermal anomalies identified by the VMC instrument aboard Venus Express. The interpretation of all emissivity data depends critically on understanding the composition of surface materials, kinetics of rock weathering and their measurement under Venus conditions. Extended theoretical studies, continued analysis of earlier spacecraft results, new atmospheric data, and measurements of mineral stability under Venus conditions have improved our understanding atmosphere-surface interactions. The calcite-wollastonite CO2 buffer has been discounted due, among other things, to

  16. Recovering the Elemental Composition of Comet Wild 2 Dust in Five Stardust Impact Tracks and Terminal Particles in Aerogel

    International Nuclear Information System (INIS)

    Ishii, H A; Brennan, S; Bradley, J P; Luening, K; Ignatyev, K; Pianetta, P

    2007-01-01

    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

  17. 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....

  18. Comparison and determination of elemental composition in Korean space foods using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Yong-Sam Chung; Sun-Ha Kim; Gwang-Min Sun; Jong-Hwa Moon; Jong-Il Choi; Beom-Seok Song; Jae-Hun Kim

    2013-01-01

    A quantitative analysis of mineral contents in several kinds of foods is needed to obtain information on a comprehensive elemental composition as well as an investigation on the effects of human health and nutrition based on the dietary intake of mineral elements. In 2012, six kinds of new Korean space foods (KSF) such as sweet pumpkin porridge, dakgalbi (spicy grilled chicken), Manila clam porridge, ox leg bone-cabbage soup, ginseng-chicken porridge, and chicken curry rice were developed by KAERI, and the contents of more than 15 elements in the samples were determined using an instrumental neutron activation analysis. A certified reference material associated with a biological food sample was used for analytical quality control. The analytical results were evaluated according to the elemental concentrations with KSF samples and compared with the reported values. These results will be applied toward the identification of gamma-irradiated foods. (author)

  19. 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.

  20. 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.

  1. Penetration of sub-micron aerosol droplets in composite cylindrical filtration elements

    International Nuclear Information System (INIS)

    Geurts, Bernard J.; Pratte, Pascal; Stolz, Steffen; Stabbert, Regina; Poux, Valerie; Nordlund, Markus; Winkelmann, Christoph

    2011-01-01

    Advection-diffusion transport of aerosol droplets in composite cylindrical filtration elements is analyzed and compared to experimental data. The penetration, characterizing the fraction of droplets that passes through the pores of a filtration element, is quantified for a range of flow rates. The advection-diffusion transport in a laminar Poiseuille flow is treated numerically for slender pores using a finite difference approach in cylindrical coordinates. The algebraic dependence of the penetration on the Peclet number as predicted theoretically, is confirmed by experimental findings at a variety of aspect ratios of the cylindrical pores. The effective penetration associated with a composite filtration element consisting of a set of parallel cylindrical pores is derived. The overall penetration of heterogeneous composite filtration elements shows an algebraic dependence to the fourth power on the radii of the individual pores that are contained. This gives rise to strong variations in the overall penetration in cases with uneven distributions of pore sizes, highly favoring filtration by the larger pores. The overall penetration is computed for a number of basic geometries, providing a point of reference for filtration design and experimental verification.

  2. 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.

  3. Finite element analysis of composite beam-to-column connection with cold-formed steel section

    Science.gov (United States)

    Firdaus, Muhammad; Saggaff, Anis; Tahir, Mahmood Md

    2017-11-01

    Cold-formed steel (CFS) sections are well known due to its lightweight and high structural performance which is very popular for building construction. Conventionally, they are used as purlins and side rails in the building envelopes of the industrial buildings. Recent research development on cold-formed steel has shown that the usage is expanded to the use in composite construction. This paper presents the modelling of the proposed composite connection of beam-to-column connection where cold-formed steel of lipped steel section is positioned back-to-back to perform as beam. Reinforcement bars is used to perform the composite action anchoring to the column and part of it is embedded into a slab. The results of the finite element and numerical analysis has showed good agreement. The results show that the proposed composite connection contributes to significant increase to the moment capacity.

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

    KAUST Repository

    Martiny, Adam C.; Talarmin, Agathe Anne Gaelle; Mouginot, Cé line; Lee, Jeanette A.; Huang, Jeremy S.; Gellene, Alyssa G.; Caron, David A.

    2015-01-01

    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.

  5. New evaluation method of crack growth in SiC/SiC composites using interface elements

    International Nuclear Information System (INIS)

    Serizawa, H.; Ando, M.; Lewinsohn, C.A.; Murakawa, H.

    2000-01-01

    Crack propagation behavior in SiC/SiC composites was analyzed using a new computer simulation method that included time-dependent interface elements. The simulation method was used to describe the time-dependent crack growth in SiC/SiC composites under four-point bending of single-edge-notched beam bend-bars. Two methods were used to simulate time-dependent crack growth in SiC/SiC composites due to fiber creep. In one method, the creep property was introduced into the interface elements by the general method of finite element method (FEM) analysis. In the second method, a new technique making the best use of the potential function was used to represent crack closure tractions due to creeping fibers. The stage-II slow crack growth of a general creep deformation was simulated by both methods. Additionally, stage-III crack growth and the transition from stage-II to stage-III could be simulated by the new method. The new method has the potential to completely simulate time-dependent crack growth behavior in SiC/SiC composites due to fiber creep

  6. 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.

  7. Surface analysis of WC--Co composite materials (2) Quantitative Auger electron spectrometry

    International Nuclear Information System (INIS)

    Tongson, L.L.; Biggers, J.V.; Dayton, G.O.; Bind, J.M.; Knox, B.E.

    1978-01-01

    The unique sensitivity of Auger electron spectrometry (AES) to combined carbon has been exploited in measuring the surface compositions of hot-pressed, conventionally sintered and mixed powders of WC--Co composite materials. AES sensitivity factors for tungsten and carbon (in WC) relative to cobalt were determined. The concentrations of the major elements in hot-pressed samples measured with AES using the relative sensitivity method were compared to those obtained independently by electron microprobe (EMP) and x-ray fluorescence (XRF) techniques. Corollary studies using ion scattering spectrometry (ISS) showed the absence of (1) matrix effects in the AES measurements, (2) preferential sputtering during ion bombardment, and (3) deposition of the easier-to-sputter component (cobalt) onto WC

  8. Analysis of some metallic elements and metalloids composition and relationships in parasol mushroom Macrolepiota procera.

    Science.gov (United States)

    Falandysz, Jerzy; Sapkota, Atindra; Dryżałowska, Anna; Mędyk, Małgorzata; Feng, Xinbin

    2017-06-01

    The aim of the study was to characterise the multi-elemental composition and associations between a group of 32 elements and 16 rare earth elements collected by mycelium from growing substrates and accumulated in fruiting bodies of Macrolepiota procera from 16 sites from the lowland areas of Poland. The elements were quantified by inductively coupled plasma quadrupole mass spectrometry using validated method. The correlation matrix obtained from a possible 48 × 16 data matrix has been used to examine if any association exits between 48 elements in mushrooms foraged from 16 sampling localizations by multivariate approach using principal component (PC) analysis. The model could explain up to 93% variability by eight factors for which an eigenvalue value was ≥1. Absolute values of the correlation coefficient were above 0.72 (significance at p < 0.05) for 43 elements. From a point of view by consumer, the absolute content of Cd, Hg, Pb in caps of M. procera collected from background (unpolluted) areas could be considered elevated while sporadic/occasional ingestion of this mushroom is considered safe. The multivariate functional analysis revealed on associated accumulation of many elements in this mushroom. M. procera seem to possess some features of a bio-indicative species for anthropogenic Pb but also for some geogenic metals.

  9. Effect of changes in environment on the variation in elemental composition of airborne dust

    International Nuclear Information System (INIS)

    Miyamoto, Yutaka; Saito, Yoko; Magara, Masaaki; Sakurai, Satoshi; Usuda, Shigekazu

    2004-01-01

    For the research on environmental impact caused by nuclear activities, we are developing monitoring technique to measure radioactivity, isotopic and elemental composition in airborne dust, which contains nuclear materials and radioactive elements released from nuclear facilities. We focus on its elimination process such as wash-out by rainfall and adsorption to plants in the processes which affect the amounts and composition of the airborne dust. Recently at JAERI-Tokai, a number of pine trees to arrest sand shifting were cut down. This gave us a good opportunity to examine the effect of presence of the trees on the variation in elemental composition of airborne dust, therefore, we collected dust samples with a high-volume sampler before and after felling the trees, and analyzed them by means of instrumental neutron activation analysis. No change was observed in the amount, Al- and Sc- concentrations of the dust collected before and after felling the trees nearby the sampling site. There were correlations between the elemental concentration of Zn and that of Sb, and between Zn and As. These elements might originate from some by-products of social activities such as fly ashes. If found that the concentration of these elements after felling the trees decrease to 60% of the concentration before the works. The histograms of concentration of Cl in the airborne samples were compiled using the samples which the average of relative humidity in the period of the sample collection was 70-80%. The Cl concentration in the airdust after felling the trees at the seaside was three times higher than that concentration before the works. It found that the trees can eliminate more effectively the aerosols such as sea-salt than soil from the atmosphere. (author)

  10. Elemental composition and structural characteristics of as-received TriTaniumTM orthodontic archwire

    Science.gov (United States)

    Ilievska, I.; Petrov, V.; Mihailov, V.; Karatodorov, S.; Andreeva, L.; Zaleski, A.; Mikli, V.; Gueorgieva, M.; Petrova, V.; Stoyanova-Ivanova, A.

    2018-03-01

    Orthodontic archwires are among the most important devices of fixed orthodontic therapy. Many types of archwires are made available on the market by various manufacturers with different elemental composition and structural characteristics. Knowing this information is important when choosing a suitable archwire for a particular stage of orthodontic treatment. The aim of our study is to characterize a new type orthodontic archwires (TriTaniumTM, American Orthodontics) before their placement in the oral cavity. To achieve the aim, we used modern methods for determining their elemental composition and structural characteristics: laser-induced plasma spectroscopy (LIBS), X-ray diffraction analysis (XRD), scanning electronic microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and differential scanning calorimetry (DSC). The results obtained from the qualitative elemental analysis by LIBS and the quantitative elemental analysis by EDX showed that Ni and Ti are the main elements in the archwire studied. The room-temperature XRD patterns showed peaks typical for a Ni-Ti alloy with an austenite-type structure. Monitoring the phase transitions by means of DSC measurements in the temperature range from –50 °C to +50 °C, we showed that in TriTaniumTM archwires, besides the austenite to martensite transition, there exists a rhombohedral intermediate phase (R phase). This study will be useful in assisting orthodontists in applying appropriate nickel-titanium orthodontic archwires in the clinical practice.

  11. The Elemental Composition of Normal and Irradiated Rice Moth Corcyra Cephalonica (Staint) (Lepidoptera-Pyralidae)

    International Nuclear Information System (INIS)

    Abassy, S.A.

    2012-01-01

    The objective of this study was to determine the variation induced in the elemental composition of the total body tissue of corcyra cephalonica Adult males and females wear irradiated as adult with 50,150 and 250 Gy or as, 5 days old egg with 25 Gy and 5 days old pupae with 50 Gy .The result obtained showed that phosphorus was the highest concentrated element in males but in case of female, potassium was the most abundant element. We notice that the arrangement of the ten elements was changed as a result of irradiation. In general, there was a slight difference in elemental composition between sexes in irradiated adults and immature stages. The effect of gamma irradiation was extended from 5 days old eggs to adults. The results indicated that adults emerged from irradiated 5 days old eggs were more sensitive than older one. The difference was always dose dependent. Radiation dis infestations method could be used for the control of insects. It is safer than other means of control and, the minimal required dose does not cause undesirable changes

  12. A structural model for composite rotor blades and lifting surfaces

    Science.gov (United States)

    Rehfield, Lawrence W.; Atilgan, Ali R.

    1987-01-01

    Composite material systems are currently candidates for aerospace structures, primarily for the design flexibiity they offer i.e., it is possible to tailor the material and manufacturing approach to the application. Two notable examples are the wing of the Grumman/USAF/DARPA X-29 and rotor blades under development by the U.S.A. Aerostructures Directorate (AVSCOM), Langley Research Center. A working definition of elastic or structural tailoring is the use of structural concept, fiber orientation, ply stacking sequence, and a blend of materials to achieve specific performance goals. In the design process, choices of materials and dimensions are made which produce specific response characteristics which permit the selected goals to be achieved. Common choices for tailoring goals are preventing instabilities or vibration resonances or enhancing damage tolerance. An essential, enabling factor in the design of tailored composite structures is structural modeling that accurately, but simply, characterizes response. The objective of this paper is to improve the single-cell beam model for composite rotor blades or lifting surfaces and to demonstrate its usefullness in applications.

  13. Styding of meteorites of Geological museum (Kazan Federal University): magnetic properties and elemental composition

    Science.gov (United States)

    Kuzina, D.; Nourgaliev, D. K.; Gareev, B. I.; Batalin, G. A.; Silantiev, V. V.

    2016-12-01

    Investigations of different types meteorites were performed by non-destructive method using polycapillary Micro X-ray Fluorescence spectrometer M4 Tornado (Bruker). Analysis conditions were chosen individually, depending on a sample. Maximum possible current is 600mkA, voltage - up to 50 kV, minimum size of X-ray point from 25 micron. Result of the measurements is elements distribution on the surface of meteorites. Obtained data used for analyzing conclusions in chondrites, find out iron, nickel distribution in the sample (for comparison with thermomagnetic data), studying secondary alterations such as melting, diffusion. Meteorites which have small amount of material after preparing exhibition samples were studied using thermomagnetic analysis among them: Brownfield-iron (IID), Ochansk - ordinary chondrite (H4), Murchison - carbonaceous chondrite (CM2), Kainsaz - carbonaceous chondrite (CO3.2) and others. Thermomagnetic analysis shows us magneto-mineralogical composition. It makes reliably detection of pure Fe, Ni or their alloys. Measurements were carried out on express Curie balance, constructed in Laboratory of magnetism and paleomagnetism of Kazan Federal University [1]. We measured induced magnetization as a function of temperature in a constant magnetic field - 400 mT. The heating rate is 100°C/min. Thermomagnetic curves measured twice - first and second heating up to 800°C. The weight of the sample is maximum 0.1 gram. Results shows that all samples contain Fe-Ni alloys and according [2] it corresponds to Ni concentration between 4-10%. [1] Burov B.V. et al. 1986. Kazan: Publishing house of KSU, 167 p. (In Russian). [2] Cacciamani C. et al. 2006. Intermetallics, 14. 1312-1325

  14. Finite element method analysis of surface roughness transfer in micro flexible rolling

    OpenAIRE

    Qu Feijun; Xie Haibo; Jiang Zhengyi

    2016-01-01

    Micro flexible rolling aims to fabricate submillimeter thick strips with varying thickness profile, where the surface quality of products is mainly determined by initial workpiece surface roughness and subsequent surface asperity flattening process, which is affected by process parameters during rolling. This paper shows a 3D finite element model for flexible rolling of a 250 μm thick workpiece with reduction of 20 to 50%, and rolling phase with thinner thickness indicates a better ability to...

  15. Layered Manufacturing of Dental Ceramics: Fracture Mechanics, Microstructure, and Elemental Composition of Lithography-Sintered Ceramic.

    Science.gov (United States)

    Uçar, Yurdanur; Aysan Meriç, İpek; Ekren, Orhun

    2018-02-11

    To compare the fracture mechanics, microstructure, and elemental composition of lithography-based ceramic manufacturing with pressing and CAD/CAM. Disc-shaped specimens (16 mm diameter, 1.2 mm thick) were used for mechanical testing (n = 10/group). Biaxial flexural strength of three groups (In-Ceram alumina [ICA], lithography-based alumina, ZirkonZahn) were determined using the "piston on 3-ball" technique as suggested in test Standard ISO-6872. Vickers hardness test was performed. Fracture toughness was calculated using fractography. Results were statistically analyzed using Kruskal-Wallis test followed by Dunnett T3 (α = 0.05). Weibull analysis was conducted. Polished and fracture surface characterization was made using scanning electron microscope (SEM). Energy dispersive spectroscopy (EDS) was used for elemental analysis. Biaxial flexural strength of ICA, LCM alumina (LCMA), and ZirkonZahn were 147 ± 43 MPa, 490 ± 44 MPa, and 709 ± 94 MPa, respectively, and were statistically different (P ≤ 0.05). The Vickers hardness number of ICA was 850 ± 41, whereas hardness values for LCMA and ZirkonZahn were 1581 ± 144 and 1249 ± 57, respectively, and were statistically different (P ≤ 0.05). A statistically significant difference was found between fracture toughness of ICA (2 ± 0.4 MPa⋅m 1/2 ), LCMA (6.5 ± 1.5 MPa⋅m 1/2 ), and ZirkonZahn (7.7 ± 1 MPa⋅m 1/2 ) (P ≤ 0.05). Weibull modulus was highest for LCMA (m = 11.43) followed by ZirkonZahn (m = 8.16) and ICA (m = 5.21). Unlike LCMA and ZirkonZahn groups, a homogeneous microstructure was not observed for ICA. EDS results supported the SEM images. Within the limitations of this in vitro study, it can be concluded that LCM seems to be a promising technique for final ceramic object manufacturing in dental applications. Both the manufacturing method and the material used should be improved. © 2018 by the American College of Prosthodontists.

  16. Synthetic samples as imitators of elements composition for calibration in nuclear-physical methods of analysis

    International Nuclear Information System (INIS)

    Lakhov, V.M.; Gerling, V.Eh.; Il'ina, L.K.; Trojnina, G.G.; Galisheva, Eh.P.

    1987-01-01

    The papers on the problems of developing and application of synthetic standard samples (SS), imitating the substance and material (rocks, ores) element composition aimed at calibration, testing and certification of the equipment as well as check on the results of neutron-activation, X-ray spectral, X-ray radiometric, X-ray fluorescence and other nuclear-physical methods of analysis, are reviewed. It is shown that choice of SS preparation method is defined by peculiarities of analysis method for which calibration SS is designed. Experience in application of SS imitators of element composition in interlaboratory comparisons testifies to potential application of synthetic SS for calibration in different methods of analysis including, nuclear-physical ones

  17. Fabrication of fuel elements on the basis of increased concentration fuel composition

    International Nuclear Information System (INIS)

    Alexandrov, A.B.; Afanasiev, V.L.; Enin, A.A.; Suprun, V.B.

    2004-01-01

    As a part of Russian Program RERTR Reduced Enrichment for Research and Test Reactors), at NCCP, Inc. jointly with the State Scientific Centre VNIINM the mastering in industrial environment of design and fabrication process of fuel elements (FE) with increased concentration fuel compositions is performed. Fuel elements with fuel composition on the basis of dioxide uranium with nearly 4 g/cm 3 fuel concentration have been produced thus confirming the principal possibility of fuel enrichment reduction down to 20% for research reactors which were built up according to the projects of the former USSR, by increasing the oxide fuel concentration in fuel assemblies (FAs). The form and geometrical dimensions of FEs and FAs shall remain unchanged, only uranium mass in FA shall be increased. (author)

  18. Analysis of thin composite structures using an efficient hex-shell finite element

    Energy Technology Data Exchange (ETDEWEB)

    Shiri, Seddik [Universite Bordeaux, Pessac (France); Naceur, Hakim [Universite de valenciennes, Valenciennes (France)

    2013-12-15

    In this paper a general methodology for the modeling of material composite multilayered shell structures is proposed using a Hex-shell finite element modeling. The first part of the paper is devoted to the general FE formulation of the present composite 8-node Hex-shell element called SCH8, based only on displacement degrees of freedom. A particular attention is given to alleviate shear, trapezoidal and thickness locking, without resorting to the classical plane-stress assumption. The anisotropic material behavior of layered shells is modeled using a fully three dimensional elastic orthotropic material law in each layer, including the thickness stress component. Applications to laminate thick shell structures are studied to validate the methodology, and good results have been obtained in comparison with ABAQUS commercial code.

  19. Holographic Formation of Diffraction Elements for Transformation of Light Beams in Liquid Crystal - Photopolymer Compositions

    Science.gov (United States)

    Semkin, A. O.; Sharangovich, S. N.

    2018-03-01

    A theoretical model of holographic formation of diffractive optical elements for transformation of light beam field into Bessel-like fields in liquid crystal - photopolymer (LC-PPM) composite materials with a dyesensitizer is developed. Results of numerical modeling of kinetics ofvariation of the refractive index of a material in the process of formation with different relationships between the photopolymerization rates and diffusion processes are presented. Based on the results of numerical simulation, it is demonstrated that when the photopolarization process dominates, the diffractive element being formed is distorted. This leads to a change in the light field distribution at its output and consequently, to ineffective transformation of the reading beam. Thus, the necessity of optimizing of the recording conditions and of the prepolymeric composition to increase the transformation efficiency of light beam fields is demonstrated.

  20. Three-dimensional Finite Element Modelling of Composite Slabs for High Speed Rails

    Science.gov (United States)

    Mlilo, Nhlanganiso; Kaewunruen, Sakdirat

    2017-12-01

    Currently precast steel-concrete composite slabs are being considered on railway bridges as a viable alternative replacement for timber sleepers. However, due to their nature and the loading conditions, their behaviour is often complex. Present knowledge of the behaviour of precast steel-concrete composite slabs subjected to rail loading is limited. FEA is an important tool used to simulate real life behaviour and is widely accepted in many disciples of engineering as an alternative to experimental test methods, which are often costly and time consuming. This paper seeks to detail FEM of precast steel-concrete slabs subjected to standard in-service loading in high-speed rail with focus on the importance of accurately defining material properties, element type, mesh size, contacts, interactions and boundary conditions that will give results representative of real life behaviour. Initial finite element model show very good results, confirming the accuracy of the modelling procedure

  1. 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)

  2. [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.

  3. Mineral and chemical composition of rock core and surface gas composition in Horonobe Underground Research Laboratory project. Phase 1

    International Nuclear Information System (INIS)

    Hiraga, Naoto; Ishii, Eiichi

    2008-02-01

    The following three kinds of analyses were conducted for the 1st phase of the Horonobe Underground Research Laboratory Project. Mineral composition analysis of core sample. Whole rock chemical composition analysis of core sample. Surface gas composition analysis. This document summarizes the results of these analyses. (author)

  4. Elemental composition of Chesapeake Bay oyster Crassostrea virginica in the vicinity of Calvert Cliffs Nuclear Power Plant

    International Nuclear Information System (INIS)

    Gavrilas, M.; Munno, F.J.

    1984-01-01

    The stable element composition of the American oyster Crassostrea virginica collected between June 1978 and August 1983 in the Chesapeake Bay in the vicinity of Calvert Cliffs Nuclear Power Plant was analyzed by neutron activation. The minimum, maximum and the mean values of the elemental concentrations are given. The seasonal effect and the linear correlation between elements entering the oyster composition are shown. 7 references, 1 figure, 4 tables

  5. Electronic and elemental properties of the Cu{sub 2}ZnSn(S,Se){sub 4} surface and grain boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Haight, Richard; Shao, Xiaoyan; Wang, Wei; Mitzi, David B. [IBM T. J. Watson Research Center, P.O. Box 218, Yorktown Hts., New York 10598 (United States)

    2014-01-20

    X-ray and femtosecond UV photoelectron spectroscopy, secondary ion mass spectrometry and photoluminescence imaging were used to investigate the electronic and elemental properties of the CZTS,Se surface and its oxides. Oxide removal reveals a very Cu poor and Zn rich surface relative to bulk composition. O and Na are observed at the surface and throughout the bulk. Upward bending of the valence bands indicates the presence of negative charge in the surface region and the Fermi level is found near the band gap center. The presence of point defects and the impact of these findings on grain boundary properties will be described.

  6. Surface composition of Europa based on VLT observations

    Science.gov (United States)

    Ligier, N.; Poulet, F.; Carter, J.

    2016-12-01

    Jupiter's moon Europa may harbor a global salty ocean under an 80-170 km thick outer layer consisting of an icy crust (Anderson et al. 1998). Meanwhile, the 10-50 My old surface, dated by cratering rates (Pappalardo et al. 1999) implies rapid surface recycling and reprocessing that could result in tectonic activity (Kattenhorn et al. 2014) and plumes (Roth et al. 2014). The surface could thus exhibit fingerprints of chemical species, as minerals characteristics of an ocean-mantle interaction and/or organics of exobiological interest, directly originating from the subglacial ocean. In order to re-investigate the composition of Europa's surface, a global mapping campaign of the satellite was performed with the near-infrared integral field spectrograph SINFONI on the Very Large Telescope (VLT) in Chile. The high spectral binning of this instrument (0.5 nm) and large signal noise ratio in comparison to previous observations are adequate to detect sharp absorptions in the wavelength range 1.45-2.45 μm. In addition, the spatially resolved spectra we obtained over five epochs nearly cover the entire surface of Europa with a pixel scale of 12.5 by 25 m.a.s ( 35 by 70 km on Europa's surface), thus permitting a global scale study. Several icy and non-icy compounds were detected and mapped at <100 km resolution. They are unevenly distributed on the moon's surface. Amorphous and crystalline water ice are both present and, in spite of a particularly strong amorphization process likely engendered by the Io plasma torus, the crystalline form is found to be approximately twice as abundant as the amorphous ice based on the analysis of the 1.65 μm band. If the surface is dominated by small and mid-sized water ice grains (25-200 μm), crystalline water-ice grains exhibit spatial inhomogeneities in their distribution. The sulfuric acid hydrate distribution exhibits the typical "bullseye" feature on the trailing hemisphere. The presence of Mg-bearing chlorinated salts (chloride

  7. Probabilistic Failure Analysis of Bone Using a Finite Element Model of Mineral-Collagen Composites

    OpenAIRE

    Dong, X. Neil; Guda, Teja; Millwater, Harry R.; Wang, Xiaodu

    2008-01-01

    Microdamage accumulation is a major pathway for energy dissipation during the post-yield deformation of bone. In this study, a two-dimensional probabilistic finite element model of a mineral-collagen composite was developed to investigate the influence of the tissue and ultrastructural properties of bone on the evolution of microdamage from an initial defect in tension. The probabilistic failure analyses indicated that the microdamage progression would be along the plane of the initial defect...

  8. Actual methods of nuclear physics in the analysis of the elemental composition of rocks and minerals

    International Nuclear Information System (INIS)

    Leonard, M.; Tsipenyuk, Yu. M.

    1981-01-01

    In this paper two methods are described for the Nuclear Physical analysis of the elementary composition of ores, mineral rocks and principles, elementary particles and radiation sources. Some examples are given showing their applications, high sensibility, selectivity, quichness and economy in comparison with other analytical methods. They are classified by their sensibilities among other analytical techniques in the determination of a large quantity of elements. (author)

  9. Can pulpal floor debonding be detected from occlusal surface displacement in composite restorations?

    Science.gov (United States)

    Novaes, João Batista; Talma, Elissa; Las Casas, Estevam Barbosa; Aregawi, Wondwosen; Kolstad, Lauren Wickham; Mantell, Sue; Wang, Yan; Fok, Alex

    2018-01-01

    Polymerization shrinkage of resin composite restorations can cause debonding at the tooth-restoration interface. Theory based on the mechanics of materials predicts that debonding at the pulpal floor would half the shrinkage displacement at the occlusal surface. The aim of this study is to test this theory and to examine the possibility of detecting subsurface resin composite restoration debonding by measuring the superficial shrinkage displacements. A commercial dental resin composite with linear shrinkage strain of 0.8% was used to restore 2 groups of 5 model Class-II cavities (8-mm long, 4-mm wide and 4-mm deep) in aluminum blocks (8-mm thick, 10-mm wide and 14-mm tall). Group I had the restorations bonded to all cavity surfaces, while Group II had the restorations not bonded to the cavity floor to simulate debonding. One of the proximal surfaces of each specimen was sprayed with fine carbon powder to allow surface displacement measurement by Digital Image Correlation. Images of the speckled surface were taken before and after cure for displacement calculation. The experiment was simulated using finite element analysis (FEA) for comparison. Group I showed a maximum occlusal displacement of 34.7±6.7μm and a center of contraction (COC) near the pulpal floor. Group II had a COC coinciding with the geometric center and showed a maximum occlusal displacement of 17.4±3.8μm. The difference between the two groups was statistically significant (p-value=0.0007). Similar results were obtained by FEA. The theoretical shrinkage displacement was 44.6 and 22.3μm for Group I and II, respectively. The lower experimental displacements were probably caused by slumping of the resin composite before cure and deformation of the adhesive layer. The results confirmed that the occlusal shrinkage displacement of a resin composite restoration was reduced significantly by pulpal floor debonding. Recent in vitro studies seem to indicate that this reduction in shrinkage displacement

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

    International Nuclear Information System (INIS)

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

    2009-01-01

    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 μm 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 mille and + 0.18 ± 0.03 per mille for the PM 2.5 μm 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 mille ) and the ceramic brake linings (average = + 0.65 per mille ). Differences in isotopic composition were also observed between the metallic (average = + 0.18 per mille ) 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.

  11. A finite element modeling of a multifunctional hybrid composite beam with viscoelastic materials

    Science.gov (United States)

    Wang, Ya; Inman, Daniel J.

    2013-04-01

    The multifunctional hybrid composite structure studied here consists of a ceramic outer layer capable of withstanding high temperatures, a functionally graded ceramic layer combining shape memory alloy (SMA) properties of NiTi together with Ti2AlC (called Graded Ceramic/Metal Composite, or GCMeC), and a high temperature sensor patch, followed by a polymer matrix composite laced with vascular cooling channels all held together with various epoxies. Due to the recoverable nature of SMA and adhesive properties of Ti2AlC, the damping behavior of the GCMeC is largely viscoelastic. This paper presents a finite element formulation for this multifunctional hybrid structure with embedded viscoelastic material. In order to implement the viscoelastic model into the finite element formulation, a second order three parameter Golla-Hughes-McTavish (GHM) method is used to describe the viscoelastic behavior. Considering the parameter identification, a strategy to estimate the fractional order of the time derivative and the relaxation time is outlined. The curve-fitting aspects of both GHM and ADF show good agreement with experimental data obtained from dynamic mechanics analysis. The performance of the finite element of the layered multifunctional beam is verified through experimental model analysis.

  12. Surface Composition of Trojan Asteroids from Thermal-Infrared Spectroscopy

    Science.gov (United States)

    Martin, A.; Emery, J. P.; Lindsay, S. S.

    2017-12-01

    Asteroid origins provide an effective means of constraining the events that dynamically shaped the solar system. Jupiter Trojan asteroids (hereafter Trojans) may help in determining the extent of radial mixing that occurred during giant planet migration. Previous studies aimed at characterizing surface composition show that Trojans have low albedo surfaces and fall into two distinct spectral groups the near infrared (NIR). Though, featureless in this spectral region, NIR spectra of Trojans either exhibit a red or less-red slope. Typically, red-sloped spectra are associated with organics, but it has been shown that Trojans are not host to much, if any, organic material. Instead, the red slope is likely due to anhydrous silicates. The thermal infrared (TIR) wavelength range has advantages for detecting silicates on low albedo asteroids such as Trojans. The 10 µm region exhibits strong features due to the Si-O fundamental molecular vibrations. We hypothesize that the two Trojan spectral groups have different compositions (silicate mineralogy). With TIR spectra from the Spitzer Space Telescope, we identify mineralogical features from the surface of 11 Trojan asteroids, five red and six less-red. Preliminary results from analysis of the 10 µm region indicate red-sloped Trojans have a higher spectral contrast compared to less-red-sloped Trojans. Fine-grain mixtures of crystalline pyroxene and olivine exhibit a 10 µm feature with sharp cutoffs between about 9 µm and 12 µm, which create a broad flat plateau. Amorphous phases, when present, smooth the sharp emission features, resulting in a dome-like shape. Further spectral analysis in the 10 µm, 18 µm, and 30 µm band region will be performed for a more robust analysis. If all Trojans come from the same region, it is expected that they share spectral and compositional characteristics. Therefore, if spectral analysis in the TIR reinforce the NIR spectral slope dichotomy, it is likely that Trojans were sourced from

  13. Microbiologically-Facilitated Effects on the Surface Composition of Alloy 22, A Candidate Nuclear Waste Packaging Material

    International Nuclear Information System (INIS)

    Horn, J; Lian, T; Martin, S I

    2001-01-01

    The effects of microbiological activities on the surface composition of Alloy 22 was investigated. Prior studies suggesting microbially-generated selective dissolution of chromium from Alloy 22 were based solely on analyzing solubilized Alloy 22 elements. These and other investigations point to the insufficiencies of analyzing solubilized (or solubilized and reprecipitated) alloying elements to discern between homogeneous/stoichiometric dissolution and selective/non-stoichiometric dissolution of alloying elements. Therefore, an approach using X-ray Photoelectron Spectroscopy (XPS) to interrogate the surface layers of treated Alloy 22 specimens was taken to resolve this issue. Sputtering into the surface of the samples, coupled with XPS analysis at given intervals, allowed a high resolution quantitative elemental evaluation of the alloy as a function of depth. Biotically-incubated Alloy 22 show a region that could be depleted of chromium. Surfacial XPS analysis of these same coupons did not detect the presence of re-precipitated Alloy 22 component elements, also supporting the possible occurrence of non-stoichiometric dissolution. Thus, these preliminary data do not exclude the possibility of selective dissolution. It also appears that this experimental approach shows promise to unequivocally resolve this issue. Further tests using smoother-surface, more highly polished coupons should allow for better resolution between surface layers to permit a decisive determination of the mode of Alloy 22 dissolution using sputtering XPS analysis

  14. 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.

  15. 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.

  16. The Effects of Trace Elements on the Lipid Productivity and Fatty Acid Composition of Nannochloropis oculata

    Directory of Open Access Journals (Sweden)

    Xiao Dou

    2013-01-01

    Full Text Available The effects of trace elements on the lipid productivity and fatty acid composition of Nannochloropis oculata (N. oculata were studied. The results showed that trace elements had a strong influence on not only the lipid productivity but also the fatty acid composition. The addition of Fe3+, Zn2+, Mn2+, Mo6+, and EDTA and the deletion of Cu2+ and Co2+ can increase the lipid productivity. The optimum concentrations of the trace elements in the culture medium are 6 times of Fe3+ and EDTA, the same concentration of Zn2+, Mn2+, and Mo6+ as the control group, but the optimum medium has no Cu2+ or Co2+. Fe3+, Zn2+, Mn2+, Mo6+, and EDTA are indispensable during the EPA formation of N. oculata. The addition of Fe3+, Zn2+, Mn2+, Mo6+, and EDTA can strongly increase the content of EPA in the lipid of N. oculata, but the concentration of the trace elements had little influence on the level of EPA.

  17. Influence of sintering time on distribution of alloying elements composition in Zircaloy pellet

    International Nuclear Information System (INIS)

    Sigit; Muchlis B; Widjaksana; Eric, J.; Suryana, RA; Gunawan

    1996-01-01

    Influence of sintering time on distribution of alloying elements composition in zircaloy pellet has been studied. Zircaloy pellets were obtained by pressing of Zr, Fe, Cr and Sn powders mixture in adequate composition of zircaloy-4, than the green pellets were sintered at 1100 o C for 1 - 3 hours. The alloying elements (Fe, Cr and Sn) composition in zircaloy pellets as sintering product were determined by Scanning Electron Microscope - Energy Dispersive X-Ray Analyser (SEM-EDAX). The experiments showed that there was an accumulation of Sn in a site of the zircaloy green pellet of 17.46 %, but after sintering process, the Sn was distributed everywhere. The influence of sintering time up to 1 hour showed a decreasing Sn composition from 9 % to 2 % which then relatively constant, while for Fe and Cr its decreasing was relatively small, i.e. : 1.86 % to 0.6 % and 1.04 % to 0.17 % respectively. The sintering process revealed no clear grain boundaries and powder homogenization did not complete. Observation on metallographic photos showed that this condition was in initial stage of sintering process where there was a complex phenomenon i.e.: no powder homogenization in green pellet or initial heating rate was extremely quick

  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. A free surface algorithm in the N3S finite element code for turbulent flows

    International Nuclear Information System (INIS)

    Nitrosso, B.; Pot, G.; Abbes, B.; Bidot, T.

    1995-08-01

    In this paper, we present a free surface algorithm which was implemented in the N3S code. Free surfaces are represented by marker particles which move through a mesh. It is assumed that the free surface is located inside each element that contains markers and surrounded by at least one element with no marker inside. The mesh is then locally adjusted in order to coincide with the free surface which is well defined by the forefront marker particles. After describing the governing equations and the N3S solving methods, we present the free surface algorithm. Results obtained for two-dimensional and three-dimensional industrial problems of mould filling are presented. (authors). 5 refs., 2 figs

  1. Finite Element Simulation of Shot Peening: Prediction of Residual Stresses and Surface Roughness

    Science.gov (United States)

    Gariépy, Alexandre; Perron, Claude; Bocher, Philippe; Lévesque, Martin

    Shot peening is a surface treatment that consists of bombarding a ductile surface with numerous small and hard particles. Each impact creates localized plastic strains that permanently stretch the surface. Since the underlying material constrains this stretching, compressive residual stresses are generated near the surface. This process is commonly used in the automotive and aerospace industries to improve fatigue life. Finite element analyses can be used to predict residual stress profiles and surface roughness created by shot peening. This study investigates further the parameters and capabilities of a random impact model by evaluating the representative volume element and the calculated stress distribution. Using an isotropic-kinematic hardening constitutive law to describe the behaviour of AA2024-T351 aluminium alloy, promising results were achieved in terms of residual stresses.

  2. Characterization of elemental and polycyclic aromatic hydrocarbon compositions of urban air in Brisbane

    Science.gov (United States)

    Lim, McKenzie C. H.; Ayoko, Godwin A.; Morawska, Lidia

    Characterization of the elemental and polycyclic aromatic hydrocarbons (PAHs) compositions of urban air was undertaken at three major sites in Brisbane, Australia. 17 elements and 16 US EPA priority PAHs were quantified at the sites. The most commonly detected elements in the TSP and PM 2.5 fractions were Al, Cd, Co, Cr, Cu, Fe, Mn, Mo, Si, Sn, Sr and Zn. Compared to the two other sites, PM 2.5 was found to contain higher concentrations of Zr, Mo, V, Al, Mn and Sr at the Queensland University of Technology (QUT) site. In contrast, the Woolloongabba sampling site, which was highly influenced by the vehicular emission and local industrial activities, has higher concentrations of Co, Sn, Cu, Zn and Mg while ANZ site has significantly lower concentration levels of most elements than the other sites; possibly due to the shielding effect of the nearby bush and forest. NAP, PHE, ANT, FLT, PYR and CRY were the most widespread PAHs found in all sites. But only QUT and Woolloongabba bus platform sites had detectable levels of the most carcinogenic US EPA PAH, BAP. The multi-criteria decision making procedures, Preference Ranking Organisation Method for Enrichment Evaluation (PROMETHEE) and Geometrical Analysis for Interactive Aid (GAIA) were used to rank the air samples and to identify the sources of the pollutants. Thus Woolloongabba bus platform was ranked as the most polluted site on the basis of the elemental and PAH compositions of its air samples while Woolloongabba bus platform and QUT sites were ranked as the worst polluted sites in terms of PAHs and PM 2.5 elemental contents, respectively.

  3. Elemental composition of PM2.5 in the urban environment of San Juan, Argentina.

    Science.gov (United States)

    Aguilera Sammaritano, Mariela; Bustos, Daniel G; Poblete, Arnobio G; Wannaz, Eduardo D

    2018-02-01

    This study contributes to the current knowledge about air pollution in the province of San Juan, Argentina. Sampling was carried out to measure the fine particulate matter in the atmosphere (PM 2.5 ) of the city of San Juan. PM 2.5 was collected continuously during the winter and spring seasons of 2014 and 2015, and the concentrations of 14 elements (Pb, Ca, K, Cd, Ni, Cr, Mn, V, Cu, Ti, Ba, Co, Sr, and Fe) were determined in PM 2.5 filters using the technique of X-ray fluorescence by synchrotron radiation (SR-XRF). The results revealed that PM 2.5 presented annual and seasonal variations, showing a higher concentration during the winter seasons. In addition, for the elements quantified in the filters, a multivariate analysis (Positive Matrix Factorization) was performed to identify the main sources of emission of these elements in the study area, with a series of components being obtained that corresponded to their compositions, which were assigned physical meanings. The first factor, which was the most important in contribution of the sum of the measured elements (45%), was determined mainly by the elements K, Ti, V, Mn, and Fe, which came predominantly from soil particles. The second factor contributed 30% to the measured species in PM 2.5 , with higher Ba and Zn content perhaps being related to emissions from vehicular traffic. Finally, the third factor, in which Pb, Cr, and Ca predominated, may be an indicator of industrial activity and contributed 25% of the sum of the measured elements of PM 2.5 . The results of this study provide the first PM composition database in the province, and this can now be used in the development of mitigation and prevention programs.

  4. Microtomography evaluation of dental tissue wear surface induced by in vitro simulated chewing cycles on human and composite teeth

    Directory of Open Access Journals (Sweden)

    Rossella Bedini

    2012-01-01

    Full Text Available In this study a 3D microtomography display of tooth surfaces after in vitro dental wear tests has been obtained. Natural teeth have been compared with prosthetic teeth, manufactured by three different polyceramic composite materials. The prosthetic dental element samples, similar to molars, have been placed in opposition to human teeth extracted by paradontology diseases. After microtomography analysis, samples have been subjected to in vitro fatigue test cycles by servo-hydraulic mechanical testing machine. After the fatigue test, each sample has been subjected again to microtomography analysis to obtain volumetric value changes and dental wear surface images. Wear surface images were obtained by 3D reconstruction software and volumetric value changes were measured by CT analyser software. The aim of this work has been to show the potential of microtomography technique to display very clear and reliable wear surface images. Microtomography analysis methods to evaluate volumetric value changes have been used to quantify dental tissue and composite material wear.

  5. Evaluation of Alternative Peel Ply Surface Preparation Methods of SC-15 Epoxy / Fiberglass Composite Surfaces for Secondary Bonding

    Science.gov (United States)

    2014-01-01

    prepared composite surfaces. Examination of the surface compositions will show differences in makeup and identify any transfer of contaminants...by carefully brushing the specimen with a lint-free cloth followed by a high-pressure nitrogen gas stream. 3.2 X-ray Photospectroscopy (XPS

  6. Surface protein composition of Aeromonas hydrophila strains virulent for fish: identification of a surface array protein

    International Nuclear Information System (INIS)

    Dooley, J.S.G.; Trust, T.J.

    1988-01-01

    The surface protein composition of members of a serogroup of Aeromonas hydrophila was examined. Immunoblotting with antiserum raised against formalinized whole cells of A. hydrophila TF7 showed a 52K S-layer protein to be the major surface protein antigen, and impermeant Sulfo-NHS-Biotin cell surface labeling showed that the 52K S-layer protein was the only protein accessible to the Sulfo-NHS-Biotin label and effectively masked underlying outer membrane (OM) proteins. In its native surface conformation the 52K S-layer protein was only weakly reactive with a lactoperoxidase 125 I surface iodination procedure. A UV-induced rough lipopolysaccharide (LPS) mutant of TF7 was found to produce an intact S layer, but a deep rough LPS mutant was unable to maintain an array on the cell surface and excreted the S-layer protein into the growth medium, indicating that a minimum LPS oligosaccharide size required for A. hydrophila S-layer anchoring. The native S layer was permeable to 125 I in the lactoperoxidase radiolabeling procedure, and two major OM proteins of molecular weights 30,000 and 48,000 were iodinated. The 48K species was a peptidoglycan-associated, transmembrane protein which exhibited heat-modifiable SDS solubilization behavior characteristic of a porin protein. A 50K major peptidoglycan-associated OM protein which was not radiolabeled exhibited similar SDS heat modification characteristics and possibly represents a second porin protein

  7. Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface Properties

    KAUST Repository

    Ben-Sasson, Moshe

    2014-01-07

    Biofouling is a major operational challenge in reverse osmosis (RO) desalination, motivating a search for improved biofouling control strategies. Copper, long known for its antibacterial activity and relatively low cost, is an attractive potential biocidal agent. In this paper, we present a method for loading copper nanoparticles (Cu-NPs) on the surface of a thin-film composite (TFC) polyamide RO membrane. Cu-NPs were synthesized using polyethyleneimine (PEI) as a capping agent, resulting in particles with an average radius of 34 nm and a copper content between 39 and 49 wt.%. The positive charge of the Cu-NPs imparted by the PEI allowed a simple electrostatic functionalization of the negatively charged RO membrane. We confirmed functionalization and irreversible binding of the Cu-NPs to the membrane surface with SEM and XPS after exposing the membrane to bath sonication. We also demonstrated that Cu-NP functionalization can be repeated after the Cu-NPs dissolve from the membrane surface. The Cu-NP functionalization had minimal impact on the intrinsic membrane transport parameters. Surface hydrophilicity and surface roughness were also maintained, and the membrane surface charge became positive after functionalization. The functionalized membrane exhibited significant antibacterial activity, leading to an 80-95% reduction in the number of attached live bacteria for three different model bacterial strains. Challenges associated with this functionalization method and its implementation in RO desalination are discussed. © 2013 American Chemical Society.

  8. Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface Properties

    KAUST Repository

    Ben-Sasson, Moshe; Zodrow, Katherine R.; Genggeng, Qi; Kang, Yan; Giannelis, Emmanuel P.; Elimelech, Menachem

    2014-01-01

    Biofouling is a major operational challenge in reverse osmosis (RO) desalination, motivating a search for improved biofouling control strategies. Copper, long known for its antibacterial activity and relatively low cost, is an attractive potential biocidal agent. In this paper, we present a method for loading copper nanoparticles (Cu-NPs) on the surface of a thin-film composite (TFC) polyamide RO membrane. Cu-NPs were synthesized using polyethyleneimine (PEI) as a capping agent, resulting in particles with an average radius of 34 nm and a copper content between 39 and 49 wt.%. The positive charge of the Cu-NPs imparted by the PEI allowed a simple electrostatic functionalization of the negatively charged RO membrane. We confirmed functionalization and irreversible binding of the Cu-NPs to the membrane surface with SEM and XPS after exposing the membrane to bath sonication. We also demonstrated that Cu-NP functionalization can be repeated after the Cu-NPs dissolve from the membrane surface. The Cu-NP functionalization had minimal impact on the intrinsic membrane transport parameters. Surface hydrophilicity and surface roughness were also maintained, and the membrane surface charge became positive after functionalization. The functionalized membrane exhibited significant antibacterial activity, leading to an 80-95% reduction in the number of attached live bacteria for three different model bacterial strains. Challenges associated with this functionalization method and its implementation in RO desalination are discussed. © 2013 American Chemical Society.

  9. Microwave and plasma-assisted modification of composite fiber surface topography

    Science.gov (United States)

    Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Bigelow, Timothy S [Knoxville, TN

    2003-02-04

    The present invention introduces a novel method for producing an undulated surface on composite fibers using plasma technology and microwave radiation. The undulated surface improves the mechanical interlocking of the fibers to composite resins and enhances the mechanical strength and interfacial sheer strength of the composites in which they are introduced.

  10. Elemental composition of aerosol particles from two atmospheric monitoring stations in the Amazon Basin

    International Nuclear Information System (INIS)

    Artaxo, P.; Gerab, F.; Rabello, M.L.C.

    1993-01-01

    One key region for the study of processes that are changing the composition of the global atmosphere is the Amazon Basin tropical rain forest. The high rate of deforestation and biomass burning is emitting large amounts of gases and fine-mode aerosol particles to the global atmosphere. Two background monitoring stations are operating continuously measuring aerosol composition, at Cuiaba, and Serra do Navio. Fine- and coarse-mode aerosol particles are being collected using stacked filter units. Particle induced X-ray emission (PIXE) was used to measure concentrations of up to 21 elements: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Se, Br, Rb, Sr, Zr, and Pb. The elemental composition was measured at the new PIXE facility from the University of Sao Paulo, using a dedicated 5SDH tandem Pelletron nuclear accelerator. Absolute principal factor analysis (APFA) has derived absolute elemental source profiles. At the Serra do Navio sampling site a very clean background aerosol is being observed. Biogenic aerosol dominates the fine-mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and FPM. Three components dominate the aerosol composition: Soil dust particles, the natural biogenic release by the forest, and a marine aerosol component. At the Cuiaba site, during the dry season, a strong component of biomass burning is observed. An aerosol mass concentration up to 120 μg/m 3 was measured. APFA showed three components: Soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, FPM, K, Cl) and natural biogenic particles (K, S, Ca, Mn, Zn). The fine-mode biogenic component of both sites shows remarkable similarities, although the two sampling sites are 3000 km apart. Several essential plant nutrients like P, K, S, Ca, Ni and others are transported in the atmosphere as a result of biomass burning processes. (orig.)

  11. An adaptive finite element method for simulating surface tension with the gradient theory of fluid interfaces

    KAUST Repository

    Kou, Jisheng; Sun, Shuyu

    2014-01-01

    The gradient theory for the surface tension of simple fluids and mixtures is rigorously analyzed based on mathematical theory. The finite element approximation of surface tension is developed and analyzed, and moreover, an adaptive finite element method based on a physical-based estimator is proposed and it can be coupled efficiently with Newton's method as well. The numerical tests are carried out both to verify the proposed theory and to demonstrate the efficiency of the proposed method. © 2013 Elsevier B.V. All rights reserved.

  12. An adaptive finite element method for simulating surface tension with the gradient theory of fluid interfaces

    KAUST Repository

    Kou, Jisheng

    2014-01-01

    The gradient theory for the surface tension of simple fluids and mixtures is rigorously analyzed based on mathematical theory. The finite element approximation of surface tension is developed and analyzed, and moreover, an adaptive finite element method based on a physical-based estimator is proposed and it can be coupled efficiently with Newton\\'s method as well. The numerical tests are carried out both to verify the proposed theory and to demonstrate the efficiency of the proposed method. © 2013 Elsevier B.V. All rights reserved.

  13. Finite element method analysis of surface roughness transfer in micro flexible rolling

    Directory of Open Access Journals (Sweden)

    Qu Feijun

    2016-01-01

    Full Text Available Micro flexible rolling aims to fabricate submillimeter thick strips with varying thickness profile, where the surface quality of products is mainly determined by initial workpiece surface roughness and subsequent surface asperity flattening process, which is affected by process parameters during rolling. This paper shows a 3D finite element model for flexible rolling of a 250 μm thick workpiece with reduction of 20 to 50%, and rolling phase with thinner thickness indicates a better ability to decrease the surface roughness. Four types of initial workpiece surface roughness are studied in the simulation, and the influences of process parameters, such as friction coefficient, rolling speed and roll gap adjusting speed, on surface asperity flattening of workpieces with different initial surface roughness have been numerically investigated and analysed.

  14. Elemental composition of Usnea sp lichen from Potter Peninsula, 25 de Mayo (King George) Island, Antarctica

    International Nuclear Information System (INIS)

    Bubach, Débora; Catán, Soledad Perez; Di Fonzo, Carla; Dopchiz, Laura

    2016-01-01

    Several pollutants, which include metals, are present in the Antarctic atmosphere, snow, marine and terrestrial organisms. This work reports the elements incorporated by Usnea sp thalli in Potter Peninsula, 25 de Mayo (King George) Island, South Shetlands, Antarctica. Geological origin was analyzed as possible sources of elements. For this purpose, correlations were done using a geochemical tracer, principal component analysis and enrichment factors were computed. Lithophile elements from particulate matter were present in most of the sampling sites. Bromine, Se and Hg showed the highest enrichment factors suggesting other sources than the particulate matter. Mercury values found in Usnea sp were in the same range as those reported for Deception Island (South Shetlands) and remote areas from the Patagonia Andes. - Highlights: • Hg enrichment factor was higher in ASPA than in human settlements area. • The elemental composition in Usnea sp from Antarctica reflected the human influence. • Bromine, Ca, Sr, Se, Fe, Hg and K contents indicated origins natural and anthropic. • The data will be considered as baselines for Potter Peninsula, King George Island. - This study provides recent element contents in Usnea sp from Potter Peninsula, South Shetland Islands, Antarctica. Some of them are the first concentration reported by Argentina.

  15. Elemental composition of herbal medicines sold over-the-counter in Sao Paulo city, Brazil

    International Nuclear Information System (INIS)

    Moreira, H.S.

    2011-01-01

    In Brazil, the use of herbal medicines is very popular due to its immense flora, cultural aspects and to the popular belief that herbs, which are of natural origin, are safe and without undesirable side effects. Aside from that public interest in natural therapies, the use of herbal medicines has increased expressively due to the high cost of synthetic medicines. In this study, elemental compositions of herbal medicines from the species Ginseng, Ginkgo biloba, Centella asiatica, Mulberry and Aloe vera supplied by different suppliers were evaluated by neutron activation analysis. The concentrations of As, Ba, Br, Ca, Cl, Co, Cr, Cs, Fe, Hf, K, Mg, Mn, Na, Rb, Sb, Sc, Th, Zn and some lanthanides were determined in these samples. Comparisons made between the results indicated differences in their elemental contents depending on the plant species, origins of the samples and the age of the leaves. The results also showed that the herbal medicines contain elements such as Ca, Co, K, Fe, Mg and Zn known as essential to humans and for treatment and prevention of diseases. Toxic elements such as Hg, Cd and Cu were not detected. Elements As and Sb were detected in some samples but at very low concentrations at the μg kg -1 levels. Herbal medicine results were also compared to literature values. Biological certified reference material was analyzed for quality control of the analytical results. (author)

  16. Surface properties of thermally treated composite wood panels

    Science.gov (United States)

    Croitoru, Catalin; Spirchez, Cosmin; Lunguleasa, Aurel; Cristea, Daniel; Roata, Ionut Claudiu; Pop, Mihai Alin; Bedo, Tibor; Stanciu, Elena Manuela; Pascu, Alexandru

    2018-04-01

    Composite finger-jointed spruce and oak wood panels have been thermally treated under standard pressure and oxygen content conditions at two different temperatures, 180 °C and respectively 200 °C for short time periods (3 and 5 h). Due to the thermally-aided chemical restructuration of the wood components, a decrease in water uptake and volumetric swelling values with up to 45% for spruce and 35% for oak have been registered, comparing to the reference samples. In relation to water resistance, a 15% increase of the dispersive component of the surface energy has been registered for the thermal-treated spruce panels, which impedes water spreading on the surface. The thermal-treated wood presents superior resistance to accelerated UV exposure and subsequently, with up to 10% higher Brinell hardness values than reference wood. The proposed thermal treatment improves the durability of the finger-jointed wood through a more economically and environmental friendly method than traditional impregnation, with minimal degradative impact on the structural components of wood.

  17. Near Surface CO2 Triple Oxygen Isotope Composition

    Directory of Open Access Journals (Sweden)

    Sasadhar Mahata

    2016-02-01

    Full Text Available The isotopic composition of carbon dioxide in the atmosphere is a powerful tool for constraining its sources and sinks. In particular, the 17O oxygen anomaly [Δ17O = 1000 × ln(1 + δ17O/1000 - 0.516 × 1000 × ln(1 + δ18O/1000], with a value > 0.5‰ produced in the middle atmosphere, provides an ideal tool for probing the exchange of carbon dioxide between the biosphere/hydrosphere and atmosphere. The biosphere/hydrosphere and anthropogenic emissions give values ≤ 0.3‰. Therefore, any anomaly in near surface CO2 would reflect the balance between stratospheric input and exchange with the aforementioned surface sources. We have analyzed Δ17O values of CO2 separated from air samples collected in Taipei, Taiwan, located in the western Pacific region. The obtained mean anomaly is 0.42 ± 0.14‰ (1-σ standard deviation, in good agreement with model prediction and a published decadal record. Apart from typically used δ13C and δ18O values, the Δ17O value could provide an additional tracer for constraining the carbon cycle.

  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. Elemental composition by EDXRF of marine sponges from the Berlengas portuguese natural park - western portuguese coast

    International Nuclear Information System (INIS)

    Araujo, Maria Fatima; Conceicao, Ana; Barbosa, Teresa

    2001-01-01

    Marine sponges are sedentary and unselective filter-feeding metazoans, which are nowadays represented by more than six thousand species with the Demospongiae being the most representative, inhabiting all aquatic environments. Due to their way of feeding, by filtering large amounts of water, these benthic organisms are particularly exposed to pollutants. Previous studies have demonstrated their aptitude in being used as environmental monitors. Besides, some authors have evidenced a selective bio-accumulation capability for some transition elements (e.g. Ni, Zn) which is dependent on the species. The present work aims at the investigation of marine sponges collected at the Berlengas Islands located at Western Portuguese Coastal area. These islands constitute a National Park with controlled access and low signal of anthropogenic influences, being a nearly ideal habitat to evaluate a possible selective bio-accumulation. Thirty-five sponges collected in August 1998, at the Berlengas National Park were classified and analysed by Energy-Dispersive X-Ray Fluorescence Spectrometry (EDXRF). The major, minor and some trace elements: Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, I and Pb were determined. Besides, sediment samples were also taken from the area to assess some lithological influence on the sponge composition. Due to the high percentage of elements that do not emit characteristic X-ray lines, absorption corrections for quantitative calculations were carried out taking into account the ratio between the inelastic and elastic scattered incident radiation of compounds and standard reference materials, from a silver secondary target. A lithological influence on the sponge major elemental composition is demonstrated. The absence of any trace metal contamination was confirmed and a clear selective bio-accumulation in some trace elements, such as Ni, Zn and As was detected

  20. Surface Compositions of Red Giant Stars in Globular Clusters

    Science.gov (United States)

    Cheng, Eric; Lau, Marie; Smith, Graeme; Chen, Brian

    2018-01-01

    Globular clusters (GCs) are excellent “laboratories” to study the formation and evolution of our galaxy. In order to understand, more specifically, the chemical compositions and stellar evolution of the stars in GCs, we ask whether or not deep internal mixing occurs in red giants or if in fact the compositions come from the primordial interstellar medium or previous generations of stars. It has been discovered that as a star evolves up the red giant branch, the surface carbon abundance decreases, which is evidence of deep internal mixing. We questioned whether these processes also affect O or Na abundance as a star evolves. We collected measurement data of red giants from GCs out of academic journals and sorted the data into catalogs. Then, we plotted the catalogs into figures, comparing surface O and Na each with stellar luminosity. Statistical tests were ran to quantify the amount of correlation between the variables. Out of 27 GCs, we concluded that eight show a positive correlation between Na and luminosity, and two show a negative correlation between O and luminosity. Properties of GCs were compared to determine if chemical distribution in stars depends on GCs as the self-enrichment scenario suggests. We created histograms of sodium distribution to test for bimodality to examine if there are separate trends in each GC. In six GCs, two different sequences of red giants appear for Na versus luminosity, suggesting evidence that the depth of mixing may differ among each red giant in a GC. This study has provided new evidence that the changing chemical abundances on the surfaces of red giants can be due to stellar evolutionary effects and deep internal mixing, which may not necessarily depend on the GC and may differ in depth among each red giant. Through this study, we learn more about stellar evolution which will eventually help us understand the origins of our universe. Most of this work was carried out by high school students working under the auspices of

  1. Enhancing Surface Finish of Additively Manufactured Titanium and Cobalt Chrome Elements Using Laser Based Finishing

    Science.gov (United States)

    Gora, Wojciech S.; Tian, Yingtao; Cabo, Aldara Pan; Ardron, Marcus; Maier, Robert R. J.; Prangnell, Philip; Weston, Nicholas J.; Hand, Duncan P.

    Additive manufacturing (AM) offers the possibility of creating a complex free form object as a single element, which is not possible using traditional mechanical machining. Unfortunately the typically rough surface finish of additively manufactured parts is unsuitable for many applications. As a result AM parts must be post-processed; typically mechanically machined and/or and polished using either chemical or mechanical techniques (both of which have their limitations). Laser based polishing is based on remelting of a very thin surface layer and it offers potential as a highly repeatable, higher speed process capable of selective area polishing, and without any waste problems (no abrasives or liquids). In this paper an in-depth investigation of CW laser polishing of titanium and cobalt chrome AM elements is presented. The impact of different scanning strategies, laser parameters and initial surface condition on the achieved surface finish is evaluated.

  2. Finite-elements modeling of radiant heat transfers between mobile surfaces; Modelisation par elements finis de transferts radiatifs entre surfaces mobiles

    Energy Technology Data Exchange (ETDEWEB)

    Daurelle, J V; Cadene, V; Occelli, R [Universite de Provence, 13 - Marseille (France)

    1997-12-31

    In the numerical modeling of thermal industrial problems, radiant heat transfers remain difficult to take into account and require important computer memory and long computing time. These difficulties are enhanced when radiant heat transfers are coupled with finite-elements diffusive heat transfers because finite-elements architecture is complex and requires a lot of memory. In the case of radiant heat transfers along mobile boundaries, the methods must be optimized. The model described in this paper concerns the radiant heat transfers between diffuse grey surfaces. These transfers are coupled with conduction transfers in the limits of the diffusive opaque domain. 2-D and 3-D geometries are analyzed and two configurations of mobile boundaries are considered. In the first configuration, the boundary follows the deformation of the mesh, while in the second, the boundary moves along the fixed mesh. Matter displacement is taken into account in the term of transport of the energy equation, and an appropriate variation of the thermophysical properties of the transition elements between the opaque and transparent media is used. After a description of the introduction of radiative limit conditions in a finite-elements thermal model, the original methods used to optimize calculation time are explained. Two examples of application illustrate the approach used. The first concerns the modeling of radiant heat transfers between fuel rods during a reactor cooling accident, and the second concerns the study of heat transfers inside the air-gap of an electric motor. The method of identification of the mobile surface on the fixed mesh is described. (J.S.) 12 refs.

  3. Finite-elements modeling of radiant heat transfers between mobile surfaces; Modelisation par elements finis de transferts radiatifs entre surfaces mobiles

    Energy Technology Data Exchange (ETDEWEB)

    Daurelle, J.V.; Cadene, V.; Occelli, R. [Universite de Provence, 13 - Marseille (France)

    1996-12-31

    In the numerical modeling of thermal industrial problems, radiant heat transfers remain difficult to take into account and require important computer memory and long computing time. These difficulties are enhanced when radiant heat transfers are coupled with finite-elements diffusive heat transfers because finite-elements architecture is complex and requires a lot of memory. In the case of radiant heat transfers along mobile boundaries, the methods must be optimized. The model described in this paper concerns the radiant heat transfers between diffuse grey surfaces. These transfers are coupled with conduction transfers in the limits of the diffusive opaque domain. 2-D and 3-D geometries are analyzed and two configurations of mobile boundaries are considered. In the first configuration, the boundary follows the deformation of the mesh, while in the second, the boundary moves along the fixed mesh. Matter displacement is taken into account in the term of transport of the energy equation, and an appropriate variation of the thermophysical properties of the transition elements between the opaque and transparent media is used. After a description of the introduction of radiative limit conditions in a finite-elements thermal model, the original methods used to optimize calculation time are explained. Two examples of application illustrate the approach used. The first concerns the modeling of radiant heat transfers between fuel rods during a reactor cooling accident, and the second concerns the study of heat transfers inside the air-gap of an electric motor. The method of identification of the mobile surface on the fixed mesh is described. (J.S.) 12 refs.

  4. A preliminary investigation of finite-element modeling for composite rotor blades

    Science.gov (United States)

    Lake, Renee C.; Nixon, Mark W.

    1988-01-01

    The results from an initial phase of an in-house study aimed at improving the dynamic and aerodynamic characteristics of composite rotor blades through the use of elastic couplings are presented. Large degree of freedom shell finite element models of an extension twist coupled composite tube were developed and analyzed using MSC/NASTRAN. An analysis employing a simplified beam finite element representation of the specimen with the equivalent engineering stiffness was additionally performed. Results from the shell finite element normal modes and frequency analysis were compared to those obtained experimentally, showing an agreement within 13 percent. There was appreciable degradation in the frequency prediction for the torsional mode, which is elastically coupled. This was due to the absence of off-diagonal coupling terms in the formulation of the equivalent engineering stiffness. Parametric studies of frequency variation due to small changes in ply orientation angle and ply thickness were also performed. Results showed linear frequency variations less than 2 percent per 1 degree variation in the ply orientation angle, and 1 percent per 0.0001 inch variation in the ply thickness.

  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. The controlled incorporation of foreign elements in metal surfaces by means of quantitative ion implantation

    International Nuclear Information System (INIS)

    Gries, W.H.

    1977-01-01

    Quantitative ion implantation is a powerful new method for the doping of metal surfaces with accurately known quantities of an element or one of its isotopes. It can be applied for the preparation of standards for various uses in instrumental methods of surface and bulk analysis. This paper provides selected information on some theoretical and practical aspects of quantitative ion implantation with the object of promoting the application of the method and stimulating further purposeful research on the subject. (Auth.)

  7. Coupling reduction between dipole antenna elements by using a planar meta-surface

    DEFF Research Database (Denmark)

    Saenz, Elena; Ederra, Inigo; Gonzalo, Ramon

    2009-01-01

    The mutual coupling between dipole antenna array elements using a planar meta-surface as superstrate is experimentally investigated. The meta-surface is based on grids of short metal strips and continuous wires. A comparison between the mutual coupling when the dipoles are radiating in free space...... driven dipole is fed and the others are matched with 50 Omega loads. The back-projected field on the aperture and on the E-plane is shown....

  8. Direct displacement-based design of special composite RC shear walls with steel boundary elements

    Directory of Open Access Journals (Sweden)

    H. Kazemi

    2016-06-01

    Full Text Available Special composite RC shear wall (CRCSW with steel boundary elements is a kind of lateral force resisting structural system which is used in earthquake-prone regions. Due to their high ductility and energy dissipation, CRCSWs have been widely used in recent years by structural engineers. However, there are few studies in the literature on the seismic design of such walls. Although there are many studies in the literature on the Direct Displacement-Based Design (DDBD of RC structures, however, no study can be found on DDBD of CRCSWs. Therefore, the aim of present study is to evaluate the ability of DDBD method for designing CRCSWs. In this study, four special composite reinforced concrete shear walls with steel boundary elements of 4, 8, 12 and 16 story numbers were designed using the DDBD method for target drift of 2%. The seismic behavior of the four CRCSWs was studied using nonlinear time-history dynamic analyses. Dynamic analyses were performed for the mentioned walls using 7 selected earthquake records. The seismic design parameters considered in this study includes: lateral displacement profile, inelastic dynamic inter-story drift demand, failure pattern and the composite RC shear walls overstrength factor. For each shear wall, the overall overstrength factor was calculated by dividing the ultimate dynamic base shear demand (Vu by the base shear demand (Vd as per the Direct Displacement Based-Design (DDBD method. The results show that the DDBD method can be used to design CRCSWs safely in seismic regions with predicted behavior.

  9. Elemental composition and ionization state of the solar atmosphere and solar wind

    International Nuclear Information System (INIS)

    Joselyn, J.A.C.

    1978-01-01

    Abundance measurements have always proved useful in generating and refining astrophysical theories. Some of the classical problems of astrophysics involve determining the relative abundances of elements in the atmosphere of a star from observations of its line spectrum, and then synthesizing the physical processes which would produce such abundances. Theories of the formation of the solar system are critically tested by their ability to explain observed abundances, and, elemental abundances can serve as tracers, helping to determine the origin and transport of ions. Since the solar wind originates at the sun, it can act as a diagnostic probe of solar conditions. In particular, measurements of the composition of the solar wind should be related to the solar composition. And, assuming ionization equilibrium, measurements of the relative abundances of the ionization states in the solar wind should infer coronal temperatures and temperature gradients. However, most spherically symmetric models of the solar wind are unable to explain the relationship between the composition estimated from solar observations and as measured at 1 AU; and, recent observations of significant flow speeds in the transition region raise doubts about the validity of the assumption of ionization equilibrium

  10. Possible stibnite transformation at the friction surface of the semi-metallic friction composites designed for car brake linings

    Science.gov (United States)

    Matějka, V.; Lu, Y.; Matějková, P.; Smetana, B.; Kukutschová, J.; Vaculík, M.; Tomášek, V.; Zlá, S.; Fan, Y.

    2011-12-01

    After a friction process several changes in phase composition of friction composites are often registered. High temperature, accompanied by high pressure induced during braking can cause initiation of chemical reactions which do not run at room or elevated temperatures under the atmospheric pressure. Most of the studies in the field of tribochemistry at friction surfaces of automotive semi-metallic brake linings deal with phenolic resin degradation and corrosion of metallic components. The paper addresses the formation of elemental antimony as well as the alloying process of iron with antimony observed on the surface of laboratory prepared semi-metallic friction composites containing stibnite. The role of alumina abrasives in the process of stibnite transformation is also discussed and mechanism of stibnite transformation was outlined.

  11. Finite element analysis of surface acoustic waves in high aspect ratio electrodes

    DEFF Research Database (Denmark)

    Dühring, Maria Bayard; Laude, Vincent; Khelif, Abdelkrim

    2008-01-01

    This paper elaborates on how the finite element method is employed to model surface acoustic waves generated by high aspect ratio electrodes and their interaction with optical waves in a waveguide. With a periodic model it is shown that these electrodes act as a mechanical resonator which slows...

  12. Finite Element Simulation of Sheet Metal Forming Process Using Local Interpolation for Tool Surfaces

    International Nuclear Information System (INIS)

    Hama, Takayuki; Takuda, Hirohiko; Takamura, Masato; Makinouchi, Akitake; Teodosiu, Cristian

    2005-01-01

    Treatment of contact between a sheet and tools is one of the most difficult problems to deal with in finite-element simulations of sheet forming processes. In order to obtain more accurate tool models without increasing the number of elements, this paper describes a new formulation for contact problems using interpolation proposed by Nagata for tool surfaces. A contact search algorithm between sheet nodes and the interpolated tool surfaces was developed and was introduced into the static-explicit elastoplastic finite-element method code STAMP3D. Simulations of a square cup deep drawing process with a very coarsely discretized punch model were carried out. The simulated results showed that the proposed algorithm gave the proper drawn shape, demonstrating the validity of the proposed algorithm

  13. Creating surfactant nanoparticles for block copolymer composites through surface chemistry.

    Science.gov (United States)

    Kim, Bumjoon J; Bang, Joona; Hawker, Craig J; Chiu, Julia J; Pine, David J; Jang, Se Gyu; Yang, Seung-Man; Kramer, Edward J

    2007-12-04

    A simple strategy to tailor the surface of nanoparticles for their specific adsorption to and localization at block copolymer interfaces was explored. Gold nanoparticles coated by a mixture of low molecular weight thiol end-functional polystyrene (PS-SH) (Mn = 1.5 and 3.4 kg/mol) and poly(2-vinylpyridine) homopolymers (P2VP-SH) (Mn = 1.5 and 3.0 kg/mol) were incorporated into a lamellar poly(styrene-b-2-vinylpyridine) diblock copolymer (PS-b-P2VP) (Mn = 196 kg/mol). A library of nanoparticles with varying PS and P2VP surface compositions (FPS) and high polymer ligand areal chain densities was synthesized. The location of the nanoparticles in the PS-b-P2VP block copolymer was determined by transmission electron microscopy. Sharp transitions in particle location from the PS domain to the PS/P2VP interface, and subsequently to the P2VP domain, were observed at FPS = 0.9 and 0.1, respectively. This extremely wide window of FPS values where the polymer-coated gold nanoparticles adsorb to the interface suggests a redistribution of PS and P2VP polymers on the Au surface, inducing the formation of amphiphilic nanoparticles at the PS/P2VP interface. In a second and synthetically more challenging approach, gold nanoparticles were covered with a thiol terminated random copolymer of styrene and 2-vinylpyridine synthesized by RAFT polymerization. Two different random copolymers were considered, where the molecular weight was fixed at 3.5 kg/mol and the relative incorporation of styrene and 2-vinylpyridine repeat units varied (FPS = 0.52 and 0.40). The areal chain density of these random copolymers on Au is unfortunately not high enough to preclude any contact between the P2VP block of the block copolymer and the Au surface. Interestingly, gold nanoparticles coated by the random copolymer with FPS = 0.4 were dispersed in the P2VP domain, while those with FPS = 0.52 were located at the interface. A simple calculation for the adsorption energy to the interface of the nanoparticles

  14. Nuclear-physical methods of investigation of an element composition in samples of soils and plants

    International Nuclear Information System (INIS)

    Hushmurodov, Sh.; Botaev, N.

    2002-01-01

    Soil (ground) and vegetative covers of the Earth are one of the most responsive and specific parts of the biosphere with respect to pollution. A proper control after them is of fundamental importance in creating and protecting optical surrounding. Analysis of soils and plants is a necessary and important stage in the process of investigation of microelements' migration in biogeochemical cycles. For this purpose we studied some reserved terrains of Uzbekistan to reveal a level of their contamination by heavy metals, as well as to find out typical and territorial singularities in accumulation of a number of elements by soils and plants. In order to decrease an influence of systematic errors, and to obtain more precise and reliable data, we carried out the element analysis of the samples by different methods, such as gamma-activation analysis, neutron-activation analysis, X-ray spectral analysis, and X-ray fluorescent analysis. As a result of our investigations we have obtained rather great information, which can be used in future to estimate the conditions of the surrounding nature. The investigations allowed us to determine the content of about 40 elements, as well as to show that the data, obtained by different nuclear-physical methods, are in rather good agreement. A reproducibility of the results of the methods, determined in control measurements, depends on the concentration of the analyzed elements, and is equal to 10-35 %. A comparison of the obtained data allowed us to reveal some singularities in element composition of the investigated samples depending on their type and territorial factor. It has been revealed that the data, obtained by different methods, are in rather good agreement. Our investigations allowed us to find out a series of regularities and singularities in accumulation of elements in plants, as well as to show the possibility of using nuclear-physical methods in such investigations

  15. Determination of elemental composition of coffee using UV-pulsed laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Gondal, M. A.; Baig, Umair; Dastageer, M. A.; Sarwar, Mohsin

    2016-01-01

    A detection system based on laser induced breakdown spectroscopy (LIBS) was built using 266 nm wavelength pulsed laser from the fourth harmonic of Nd:YAG laser, 500 mm spectrograph and gated ICCD camera with built-in delay generator. The LIBS system was used to study the elemental composition in coffee available in the local market of Saudi Arabia for the detection of elements in coffee samples. The LIBS spectrum of coffee sample revealed the presence magnesium, calcium, aluminum, copper, sodium, barium, bromine, cobalt, chromium, cerium manganese and molybdenum. Atomic transition line of sodium is used to study the parametric dependence of LIBS signal. The study of the dependence of LIBS signal on the laser pulse energy is proven to be linear and the dependence of LIBS signal on the time delay between the excitation and data acquisition showed a typical increase, a peak value and a decrease with the optimum excitation – acquisition delay at 400 ns.

  16. Elemental composition of the particulate matter present in the atmospheric aerosols of Sete Lagoas, MG

    International Nuclear Information System (INIS)

    Queiroz, Paula Guimaraes Moura; Jacomino, Vanusa Maria Feliciano; Menezes, Maria Angela de Barros Correia

    2007-01-01

    The main objective of this study was the identification of sources generating particulate matter in the atmospheric aerosols of Sete Lagoas, Minas Gerais. The measurement of the mineral composition was accomplished by X-ray diffractometry and the elemental concentration by neutron activation analysis. The results showed that Al, Cl, Cu, Fe, K, Mg and Na are the predominant chemical elements in the total suspended particles (TPS). The presence of Na, Ba, Cl, Cu, Eu, Fe and Sm in those particles with aerodynamic diameter smaller than 10 μm (PM 10 ), indicates that soil dust and ceramic and pig iron industries are the main sources of air quality degradation in the region. (author)

  17. 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.

  18. Elemental composition of airborne dust in the Shale Shaker House during an offshore drilling operation.

    Science.gov (United States)

    Hansen, A B; Larsen, E; Hansen, L V; Lyngsaae, M; Kunze, H

    1991-12-01

    During 2 days of an offshore drilling operation in the North Sea, 16 airborne dust samples from the atmosphere of the Shale Shaker House were collected onto filters. During this operation, drilling mud composed of a water slurry of barite (BaSO4) together with minor amounts of additives, among them chrome lignosulphonate and chrome lignite, was circulated between the borehole and the Shale Shaker House. The concentration of airborne dust in the atmosphere was determined and the elemental composition of the particles analysed by both PIXE (proton-induced X-ray emission) and ICP-MS (inductively coupled plasma-mass spectrometry). The total amount of dust collected varied from 0.04 to 1.41 mg m-3 with barium (Ba) as the single most abundant element. The open shale shakers turned out to be the major cause of generation of dust from the solid components of the drilling mud.

  19. Determination of elemental composition of coffee using UV-pulsed laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gondal, M. A., E-mail: magondal@kfupm.edu.sa; Baig, Umair; Dastageer, M. A.; Sarwar, Mohsin [Laser Research Group, Physics Department, King Fahd University of Petroleum and Minerals, P.O Box 5047, Dhahran 31261 (Saudi Arabia)

    2016-06-10

    A detection system based on laser induced breakdown spectroscopy (LIBS) was built using 266 nm wavelength pulsed laser from the fourth harmonic of Nd:YAG laser, 500 mm spectrograph and gated ICCD camera with built-in delay generator. The LIBS system was used to study the elemental composition in coffee available in the local market of Saudi Arabia for the detection of elements in coffee samples. The LIBS spectrum of coffee sample revealed the presence magnesium, calcium, aluminum, copper, sodium, barium, bromine, cobalt, chromium, cerium manganese and molybdenum. Atomic transition line of sodium is used to study the parametric dependence of LIBS signal. The study of the dependence of LIBS signal on the laser pulse energy is proven to be linear and the dependence of LIBS signal on the time delay between the excitation and data acquisition showed a typical increase, a peak value and a decrease with the optimum excitation – acquisition delay at 400 ns.

  20. Trace elements and essential oil composition in chemotypes of the aromatic plant Origanum vulgare

    International Nuclear Information System (INIS)

    Kanias, G.D.

    1998-01-01

    Trace elements, essential oil yield and its percentage composition were determined by neutron activation analysis, hydrodistillation and gas chromatography in two chemotypes of Origanum vulgare L. cultivated in the same field. Statistical tests such as analysis of variance, correlation coefficient, t-test, and multiple correlation were applied. The results showed that the samples contain the highest recorded oil yield for aromatic plants. Also, there is a statistically significant difference between the chemotypes of the plant not only in the predominant compound but in a number of other components. Iron, chromium and scandium showed a negative significant correlation with carvacrol and a positive one with thymol. Europium shows characteristic correlations with chromium, cobalt, iron and scandium within each chemotype of the plant. These correlations could make probable a role of this element in the biosynthesis of the predominant compounds. (author)

  1. 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.

  2. Chemical, mechanical and biological properties of contemporary composite surface sealers.

    Science.gov (United States)

    Anagnostou, Maria; Mountouris, George; Silikas, Nick; Kletsas, Dimitris; Eliades, George

    2015-12-01

    To evaluate the chemical, mechanical, and biological properties of modern composite surface sealers (CSS) having different compositions. The CSS products tested were Biscover LV (BC), Durafinish (DF), G-Coat Plus (GC), and Permaseal (PS). The tests performed were: (A): degree of conversion (DC%) by ATR-FTIR spectroscopy; (B): thickness of O2-inhibition layer by transmission optical microscopy; (C): surface hardness, 10 min after irradiation and following 1 week water storage, employing a Vickers indenter (VHN); (D): color (ΔE*) and gloss changes (ΔGU) after toothbrush abrasion, using L*a*b* colorimetry and glossimetry; (E): accelerated wear (GC,PS only) by an OHSU wear simulator plus 3D profilometric analysis, and (F): cytotoxicity testing of aqueous CSS eluents on human gingival fibroblast cultures employing the methyl-(3)H thymidine DNA labeling method. Statistical analyses included 1-way (A, B, ΔE*, ΔGU) and 2-way (C, F) ANOVAs, plus Tukey post hoc tests. Student's t-test was used to evaluate the results of the accelerated wear test (α=0.05 for all). The rankings of the statistical significant differences were: (A) PS (64.9)>DF,BC,GC (56.1-53.9) DC%; (B) DF,PS (12.3,9.8)>GC,BC (5.2,4.8) μm; (C): GC (37.6)>BC,DF (32.6,31.1)>PS (26.6) VHN (10 min/dry) and BC,DF (29.3,28.7)>GC(26.5)>PS(21.6) VHN (1w/water), with no significant material/storage condition interaction; (D): no differences were found among GC,DF,BC,PS (0.67-1.11) ΔE*, with all values within the visually acceptable range and PS,BC (32.8,29.4)>GC,DF (19.4,12.9) ΔGU; (E): no differences were found between GC and PS in volume loss (0.10,0.11 mm(3)), maximum (113.9,130.5 μm) and mean wear depths (30.3,27.5 μm); (F): at 1% v/v concentration, DF showed toxicity (23% vital cells vs 95-102% for others). However, at 5% v/v concentration DF (0%) and BC (9%) were the most toxic, whereas GC (58%) and PS (56%) showed moderate toxicity. Important chemical, mechanical, and biological properties exist among

  3. The University of Surrey database of elemental composition of human hair

    International Nuclear Information System (INIS)

    Altaf, W.J.; Akanle, O.A.; Admans, L.L.; Beasley, D.; Butler, C.; Spyrou, N.M.

    2004-01-01

    The elemental composition of human hair obtained from different studies at Surrey University over a period of 25 years has been recorded and forms part of a database, for biological and environmental samples, which is being developed. Instrumental neutron activation analysis (IAA), using reactor neutrons, was the principal method employed and from which reported data are presented. Elemental concentrations of Br, Ca, Ce, Cl, Co, Cr, Cs, F, Fe, Hf, K, Mg, Mn, Na, Rb, Sb, Sc, Se, V and Zn were obtained and recorded in the database. Chronological variations in two sets of subjects separated by a period of time of 16 years are also given. Variations in the concentration values of some elements related to the state of health and disease were reported for hair samples collected from subjects suffering from manic depression, senile dementia and breast cancer. Concentration values of some elements with relation to the nationality of subjects from Bulgaria, England, Kenya, Nigeria and Wales are presented and compared. This study is part of on-going research in the analysis of biomedical and bioenvironmental materials. The database is still in its infancy. (author)

  4. Finite element analysis of adanced composite structures containing mechanically fastened joints

    International Nuclear Information System (INIS)

    Baumann, E.

    1982-01-01

    Although the usual engineering practice is to ignore joint effects in finite element models of overall structures, there are times when the inclusion of fastener effects in a model is necessary for accurate analysis. This paper describes some simple but accurate methods for accommodating this modeling requirement. The approach involves correlation of test results from a few composite mechanically fastened joints with finite element analyses of joints. It is assumed that if the fastener actions in the test articles can be properly predicted by simple finite element techniques, then these same techniques can be applied to large overall structure models. During the course of this test-analysis effort it was determined that it is possible to obtain correct results for overall structure-joint analyses by using simple modeling concepts provided special care is employed. Also, some emphasis is given in this paper to the importance of properly reducing test data in order to obtain meaningful correlations with finite element analysis. Finally, for those interested, the appendix contains brief descriptions of the test results and failure modes explored in the test program. (orig.)

  5. 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...

  6. Blast response of curved carbon/epoxy composite panels: Experimental study and finite-element analysis

    International Nuclear Information System (INIS)

    Phadnis, V A; Roy, A; Silberschmidt, V V; Kumar, P; Shukla, A

    2013-01-01

    Experimental and numerical studies were conducted to understand the effect of plate curvature on blast response of carbon/epoxy composite panels. A shock-tube system was utilized to impart controlled shock loading to quasi-isotropic composite panels with differing range of radii of curvatures. A 3D Digital Image Correlation (DIC) technique coupled with high-speed photography was used to obtain out-of-plane deflection and velocity, as well as in-plane strain on the back face of the panels. Macroscopic post-mortem analysis was performed to compare yielding and deformation in these panels. A dynamic computational simulation that integrates fluid-structure interaction was conducted to evaluate the panel response in general purpose finite-element software ABAQUS/Explicit. The obtained numerical results were compared to the experimental data and showed a good correlation

  7. Elemental Composition of Mars Return Samples Using X-Ray Fluorescence Imaging at the National Synchrotron Light Source II

    Science.gov (United States)

    Thieme, J.; Hurowitz, J. A.; Schoonen, M. A.; Fogelqvist, E.; Gregerson, J.; Farley, K. A.; Sherman, S.; Hill, J.

    2018-04-01

    NSLS-II at BNL provides a unique and critical capability to perform assessments of the elemental composition and the chemical state of Mars returned samples using synchrotron radiation X-ray fluorescence imaging and X-ray absorption spectroscopy.

  8. 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.

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

    DEFF Research Database (Denmark)

    Mikkelsen, Lars Pilgaard

    2015-01-01

    Uni-directional glass fiber reinforced polymers play a central role in the task increasing the length of wind turbines blades and thereby lowering the cost of energy from wind turbine installations. During this, optimizing the mechanical performance regarding material stiffness, compression...... 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....

  10. Finite element modeling of surface subsidence induced by underground coal mining

    International Nuclear Information System (INIS)

    Su, D.W.H.

    1992-01-01

    The ability to predict the effects of longwall mining on topography and surface structures is important for any coal company in making permit applications and anticipating potential mining problems. The sophisticated finite element model described and evaluated in this paper is based upon five years of underground and surface observations and evolutionary development of modeling techniques and attributes. The model provides a very powerful tool to address subsidence and other ground control questions. The model can be used to calculate postmining stress and strain conditions at any horizon between the mine and the ground surface. This holds the promise of assisting in the prediction of mining-related hydrological effects

  11. Composite lay-up process with application of elements of augmented reality

    Science.gov (United States)

    Novák-Marcinčin, Jozef; Barna, Jozef; Janák, Miroslav; Fečová, Veronika; Nováková-Marcinčinová, L'udmila

    2012-03-01

    This article deals with virtual tools based on principles of open source philosophy in implementation area of composite lay-up technology. It describes virtual software and hardware elements that are necessary for work in augmented reality environment. In the beginning it focuses on general problems of applications of virtual components and in composite lay-up process. It clarifies the fundamental philosophy of new created application and the process called visual scripting that was used for program development. Further it provides closer view on particular logical sections, where necessary data are harvested and compared with values from virtual arrays. Also the new device is described with adjustment of operating desk, what enables detailed control of any realized manufacturing process. This positioning table can determine and set the position of the working plane using the commands in computer interface or manual changes. Information about exact position of individual layers are obtained in real time thanks to the built-in sensors. One of them manages the data change of the desk position (X, Y, Z), other checks the rotation around main axis situated in the center of the table. New software consists of 4 main logical areas with data packets comming from internal computer components as well as from external devices. In the end the displaying section is able to realize the movement process of virtual item (composite layer) according to its trajectory. Article presents new attitude in realization of composite lay-up process. Finally it deals with possible future improvements and other application possibilities.

  12. Evaluation of cavity size, kind, and filling technique of composite shrinkage by finite element.

    Science.gov (United States)

    Jafari, Toloo; Alaghehmad, Homayoon; Moodi, Ehsan

    2018-01-01

    Cavity preparation reduces the rigidity of tooth and its resistance to deformation. The purpose of this study was to evaluate the dimensional changes of the repaired teeth using two types of light cure composite and two methods of incremental and bulk filling by the use of finite element method. In this computerized in vitro experimental study, an intact maxillary premolar was scanned using cone beam computed tomography instrument (SCANORA, Switzerland), then each section of tooth image was transmitted to Ansys software using AUTOCAD. Then, eight sizes of cavity preparations and two methods of restoration (bulk and incremental) using two different types of composite resin materials (Heliomolar, Brilliant) were proposed on software and analysis was completed with Ansys software. Dimensional change increased by widening and deepening of the cavities. It was also increased using Brilliant composite resin and incremental filling technique. Increase in depth and type of filling technique has the greatest role of dimensional change after curing, but the type of composite resin does not have a significant role.

  13. Failure of structural elements made of polymer supported composite materials during the multiyear natural aging

    Science.gov (United States)

    Blinkov, Pavel; Ogorodov, Leonid; Grabovyy, Peter

    2018-03-01

    Modern high-rise construction introduces a number of limitations and tasks. In addition to durability, comfort and profitability, projects should take into account energy efficiency and environmental problems. Polymer building materials are used as substitutes for materials such as brick, concrete, metal, wood and glass, and in addition to traditional materials. Plastic materials are light, can be formed into complex shapes, durable and low, and also possess a wide range of properties. Plastic materials are available in various forms, colors and textures and require minimal or no color. They are resistant to heat transfer and diffusion of moisture and do not suffer from metal corrosion or microbial attack. Polymeric materials, including thermoplastics, thermoset materials and wood-polymer composites, have many structural and non-structural applications in the construction industry. They provide unique and innovative solutions at a low cost, and their use is likely to grow in the future. A number of polymer composite materials form complex material compositions, which are applied in the construction in order to analyze the processes of damage accumulation under the conditions of complex nonstationary loading modes, and to determine the life of structural elements considering the material aging. This paper present the results of tests on short-term compression loading with a deformation rate of v = 2 mm/min using composite samples of various shapes and sizes.

  14. Study of the elemental composition of saliva of smokers and nonsmokers by X-ray fluorescence

    International Nuclear Information System (INIS)

    Poles, Antônio A.; Balcão, Victor M.; Chaud, Marco V.; Vila, Marta M.D.C.; Aranha, Norberto; Yoshida, Valquíria M.H.; Oliveira, José M.

    2016-01-01

    Cigarette smoking is a serious public health problem. According to data from the World Health Organization, it is estimated that currently more than 1.2 billion people worldwide do tobacco use and that smoking-related diseases are responsible for about 6 million deaths each. With attention to this, it is necessary to seek preventive and prognostic of trying to reduce these numbers and alert the public in general about the danger and the harm caused by its use. Thus, the objective of the research work undertaken was to evaluate and compare the chemical composition of collected saliva samples of smokers and nonsmokers by X-ray Fluorescence analyses. 32 individuals were selected, 16 of which used cigarette on a daily basis and the other 16 had never smoked. Saliva was collected with the help of a (sterile) disposable Pasteur pipette and samples sent to the Applied Nuclear Physics Laboratory at UNISO (LAFINAU), where analyzes were carried out. Individuals who agreed to participate in the study answered a questionnaire to define their profile of inclusion and signed an informed consent form (CEP Protocol no. 831.753 of 09/10/2014). The results clearly showed that there are differences in the concentrations of chemical elements in the saliva of smokers and non-smokers. The biggest discrepancies were found at concentrations of the chemical elements Sulfur, Phosphorus, Chlorine and Potassium, and smaller differences in the concentration of the elements Calcium, Manganese, Iron, Copper, Titanium, Vanadium and Nickel. In only one saliva sample, and in quite low amounts, arsenic was detected. The results indicate that smoking produces more significant changes in the saliva of women than in men, increasing the concentration of some elements in the saliva of female smokers, much more than in the male smokers. The cigarette usage time also appears to exert a greater influence on the composition of the saliva of women than in men, indicating that the damage caused by cigarette

  15. Two approaches to form antibacterial surface: Doping with bactericidal element and drug loading

    Energy Technology Data Exchange (ETDEWEB)

    Sukhorukova, I.V.; Sheveyko, A.N.; Kiryukhantsev-Korneev, Ph.V. [National University of Science and Technology “MISIS”, Leninsky pr. 4, Moscow 119049 (Russian Federation); Anisimova, N.Y.; Gloushankova, N.A.; Zhitnyak, I.Y. [N.N Blokhin Russian Cancer Research Center of RAMS, Kashirskoe shosse 24, Moscow 115478 (Russian Federation); Benesova, J. [Institute of Experimental Medicine of the ASCR, Vídenska 1083, Prague 14220 (Czech Republic); Institute of Biophysics, 2nd Faculty of Medicine, Charles University in Prague, V Uvalu 84, Prague 15006 (Czech Republic); Amler, E. [Institute of Experimental Medicine of the ASCR, Vídenska 1083, Prague 14220 (Czech Republic); Faculty of Biomedical Engineering, Czech Technical University in Prague (Czech Republic); Shtansky, D.V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky pr. 4, Moscow 119049 (Russian Federation)

    2015-03-01

    Graphical abstract: - Highlights: • Bioactive materials with rate-controlled release of antibacterial agent. • Ag{sup +} ion release from TiCaPCON-Ag films depended on Ag content. • TiCaPCON-coated Ti network structure with blind pores loaded with co-amoxiclav. • Strong bactericidal effect of drug-loaded samples. • Antibacterial yet biocompatible and bioactive surfaces. - Abstract: Two approaches (surface doping with bactericidal element and loading of antibiotic into specially formed surface microcontainers) to the fabrication of antibacterial yet biocompatible and bioactive surfaces are described. A network structure with square-shaped blind pores of 2.6 ± 0.6 × 10{sup −3} mm{sup 3} for drug loading was obtained by selective laser sintering (SLS). The SLS-fabricated samples were loaded with 0.03, 0.3, 2.4, and 4 mg/cm{sup 2} of co-amoxiclav (amoxicillin and clavulanic acid). Ag-doped TiCaPCON films with 0.4, 1.2, and 4.0 at.% of Ag were obtained by co-sputtering of composite TiC{sub 0.5}-Ca{sub 3}(PO{sub 4}){sub 2} and metallic Ag targets. The surface structure of SLS-prepared samples and cross-sectional morphology of TiCaPCON-Ag films were studied by scanning electron microscopy. The through-thickness of Ag distribution in the TiCaPCON-Ag films was obtained by glow discharge optical emission spectroscopy. The kinetics of Ag ion release in normal saline solution was studied using inductively coupled plasma mass spectrometry. Bacterial activity of the samples was evaluated against S. epidermidis, S. aureus, and K. pneum. ozaenae using the agar diffusion test and photometric method by controlling the variation of optical density of the bacterial suspension over time. Cytocompatibility of the Ag-doped TiCaPCON films was observed in vitro using chondrocytic and MC3T3-E1 osteoblastic cells. The viability and proliferation of chondrocytic cells were determined using the MTS assay and PicoGreen assay tests, respectively. The alkaline phosphatase (ALP

  16. Origin and migration of trace elements in the surface sediments of Majuro Atoll, Marshall Islands.

    Science.gov (United States)

    Ito, Lisa; Omori, Takayuki; Yoneda, Minoru; Yamaguchi, Toru; Kobayashi, Ryuta; Takahashi, Yoshio

    2018-07-01

    The sediments of Majuro Atoll, Marshall Islands, consist of bioclastic materials, including foraminifera and coral debris. The sedimentary depth profiles of elements showed that various elements including zinc (Zn) and copper (Cu) were enriched in the upper layers of the islands of Majuro Atoll. Carbon-14 dating revealed that the sedimentation of the upper layer was completed before 1670 and 542 cal BP in Laura and Calalen, respectively. The enriched elements could be categorized by their origins: (a) terrestrial elements transported as dust (aluminum (Al) and rare earth elements (REEs)); (b) anthropogenic elements (Zn and Cu); and (c) elements supplied by seabirds (phosphorus (P)). From the results of the total amount of Al supplied to sediments for ca. 2000 years, Al in Majuro Atoll was suggested to be airborne origin. The enrichment factors of the elements normalized to Al concentration of continental crust showed that REEs were also transported as dust, while Zn and Cu were mainly of anthropogenic origin. The speciation analysis by X-ray absorption near-edge structure (XANES) showed the presence of Zn-Cu alloys originated from industrial products. It was also revealed that Zn was enriched in the surface due to anthropogenic emission after urbanization on Majuro Atoll and fixed by carbonate and phosphate at the upper layer, which inhibits migration of Zn into the deeper layer and its release to the groundwater and costal water. Hence, the fixation of heavy metals at the surface prevents their exposure to aquatic organisms and residents via fresh groundwater in the island. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Mechanical Performance of Natural / Natural Fiber Reinforced Hybrid Composite Materials Using Finite Element Method Based Micromechanics and Experiments

    OpenAIRE

    Rahman, Muhammad Ziaur

    2017-01-01

    A micromechanical analysis of the representative volume element (RVE) of a unidirectional flax/jute fiber reinforced epoxy composite is performed using finite element analysis (FEA). To do so, first effective mechanical properties of flax fiber and jute fiber are evaluated numerically and then used in evaluating the effective properties of ax/jute/epoxy hybrid composite. Mechanics of Structure Genome (MSG), a new homogenization tool developed in Purdue University, is used to calculate the hom...

  18. Calculation of Pressure Distribution at Rotary Body Surface with the Vortex Element Method

    Directory of Open Access Journals (Sweden)

    S. A. Dergachev

    2014-01-01

    Full Text Available Vortex element method allows to simulate unsteady hydrodynamic processes in incompressible environment, taking into account the evolution of the vortex sheet, including taking into account the deformation or moving of the body or part of construction.For the calculation of the hydrodynamic characteristics of the method based on vortex element software package was developed MVE3D. Vortex element (VE in program is symmetrical Vorton-cut. For satisfying the boundary conditions at the surface used closed frame of vortons.With this software system modeled incompressible flow around a cylindrical body protection elongation L / D = 13 with a front spherical blunt with the angle of attack of 10 °. We analyzed the distribution of the pressure coefficient on the body surface of the top and bottom forming.The calculate results were compared with known Results of experiment.Considered design schemes with different number of Vorton framework. Also varied radius of VE. Calculation make possible to establish the degree of sampling surface needed to produce close to experiment results. It has been shown that an adequate reproducing the pressure distribution in the transition region spherical cylindrical surface, on the windward side requires a high degree of sampling.Based on these results Can be possible need to improve on the design scheme of body's surface, allowing more accurate to describe the flow vorticity in areas with abrupt changes of geometry streamlined body.

  19. Elastic-plastic finite element analyses for reducers with constant-depth internal circumferential surface cracks

    International Nuclear Information System (INIS)

    Wu, Szu-Ying; Tsai, Bor-Jiun; Chen, Jien-Jong

    2015-01-01

    In this study, a 3-D automatic elastic-plastic finite element mesh generator is established to accurately predict the J-integral value of an arbitrary reducer with a constant-depth internal circumferential surface crack under bending and axial force. The contact pairs are used on the crack surfaces to simulate the actual contact behaviors of the crack model under loadings. In order to verify the accuracy of the proposed elastic-plastic finite element model for a reducer with a surface crack, the cracked straight pipe models are generated according to a special modeling procedure for a flawed reducer. The J-integral values along the crack front of surface crack are calculated and compared with the straight pipe models which have been verified in the previous published studies. Based on the comparison of computed results, good agreements are obtained to show the accuracy of present numerical models. More confidence on using the 3-D elastic-plastic finite element analysis for reducers with internal circumferential surface cracks can be thus established in this work

  20. Discrepancy between body surface area and body composition in cancer.

    Science.gov (United States)

    Stobäus, Nicole; Küpferling, Susanne; Lorenz, Marie-Luise; Norman, Kristina

    2013-01-01

    Calculation of cytostatic dose is typically based on body surface area (BSA) regardless of body composition. The aim of this study was to assess the discrepancy between BSA and low fat-free mass (FFM) by investigating the prevalence of low FFM with regard to BSA in 630 cancer patients. First, BSA was calculated according to DuBois and DuBois. Patients were divided into 6 categories with respect to their BSA. Each BSA category was further divided into 3 groups according to FFM: low (FFM), normal (-0.99 and 0.99 SD of mean FFM) or high (>1 SD of mean FFM), which was derived through bioelectric impedance analysis. FFM was reduced in 15.7% of patients, 69% had normal and 15.2% had high FFM. In patients with low FFM (i.e., more than-1 SD lower than the mean FFM within their BSA group), body mass index and fatigue were higher whereas functional status was reduced. Moreover, in the subcohort of patients receiving chemotherapy, absolute FFM [Hazard ratio (HR) = 0.970, P = 0.026] as well as the allocation to the low FFM group (HR = 1.644, P = 0.025) emerged as predictors of increased 1-yr mortality. In conclusion, there was a large discrepancy between FFM and BSA. Particularly women were affected by low FFM.

  1. Surface modified carbon nanoparticle papers and applications on polymer composites

    Science.gov (United States)

    Ouyang, Xilian

    Free-standing paper like materials are usually employed as protective layers, chemical filters, components of electrical batteries or supercapacitors, adhesive layers, and electronic or optoelectric components. Free-standing papers made from carbon nanoparticles have drawn increased interest because they have a variety of superior chemical and physical characteristics, such as light weight, high intrinsic mechanical properties, and extraordinary high electrical conductivity. Nanopapers fabricated from 1- D shape carbon nanofibers (CNFs) and carbon nanotubes (CNTs) are promising reinforcing materials for polymer composites, because the highly porous CNF and CNT nanopapers (porosity ˜80% and ˜70% respectively) can be impregnated with matrix polymers. In the first part of this work, polyaniline (PANI) was used to functionalize the surface of CNFs, and the resultant carbon nanopapers presented impressive mechanical strength and electrical conductivity that it could be used in the in-mold coating (IMC)/ injection molding process to achieve high electromagnetic interference (EMI) shielding effectiveness. Aniline modified (AF) CNT nanopapers were used as a 3D network in gas separation membranes. The resultant composite membranes demonstrated better and stable CO2 permeance and CO 2/H2 selectivity in a high temperature (107°C) and high pressure (15-30 atm) gas separation process, not achievable by conventional polymer membranes. In the second part, we demonstrated that 2-D graphene (GP) or graphene oxide (GO) nanosheets could be tightly packed into a film which was impermeable to most gases and liquids. GP or GO nanopapers could be coated on polymer composites. In order to achieve well-dispersed single-layer graphene in aqueous medium, we developed a facile approach to synthesize functional GP bearing benzenesulfonic acid groups which allow the preparation of nanopapers by water based assembly. With the optimized processing conditions, our best GP nanopapers could reach

  2. The association of LUR modeled PM2.5 elemental composition with personal exposure

    International Nuclear Information System (INIS)

    Montagne, Denise; Hoek, Gerard; Nieuwenhuijsen, Mark; Lanki, Timo; Pennanen, Arto; Portella, Meritxell; Meliefste, Kees; Wang, Meng; Eeftens, Marloes; Yli-Tuomi, Tarja; Cirach, Marta; Brunekreef, Bert

    2014-01-01

    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 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 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 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 2.5 did not predict measured

  3. Effect of Rare Earth Element on Microstructure and Properties of in situ Synthesized TiB2/Al Composites

    Directory of Open Access Journals (Sweden)

    QU Min

    2018-03-01

    Full Text Available The effect of rare earth element Ce, Sc and Er on TiB2 particles and matrix alloy micros-tructure of TiB2/Al composites was studied with in situ synthesis method. It shows that the addition of rare earth element improves the microstructure and properties of TiB2/Al composites notably. The particles of TiB2 are relatively homogenously distributed as adding 0.3% (mass fraction rare earth element Sc and Er, moreover, it is Er that refines the microstructure of matrix alloy most significantly, then is Sc. Similarly, it is demonstrated that the addition of Sc and Er results in better tensile strength, which is enhanced by 32% and 31%, respectively; the addition of Er also leads to the best ductility by 85% with optimal tensile property. Meanwhile, fracture morphology analysis reveals that the fracture of the composites is microporous gathered ductile fracture when adding Sc and Er. Finally, it is verified that the mechanism of rare earth element on composites lies in two aspects:one is that the addition of rare earth element improves the wettability of the composites and suppresses the agglomeration of TiB2 particles; the other is that the addition of rare earth element refines the microstructure of matrix alloy and then improves the tensile strength of the composites.

  4. Investigation of the surface composition of electrodeposited black chromium by X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Survilienė, S.; Češūnienė, A.; Jasulaitienė, V.; Jurevičiūtė, I.

    2015-01-01

    Highlights: • Black chromium electrodeposited from a Cr(III) bath is composed of oxide, hydroxide and metallic chromium. • Metallic phase is absent in black chromium electrodeposited from a Cr(III) + ZnO bath. • The near-surface layer is rich in hydroxides, whereas oxides of both metals predominate in the depth of the coatings. - Abstract: The paper reviews black chromium electrodeposited from a trivalent chromium bath containing ZnO as a second main component. The chemical compositions of the top layers of the black chromium coatings were studied by the X-ray photoelectron spectroscopy method. The surface of black chromium was found to be almost entirely covered with organic substances. To gain information on the state of each element in the deposit bulk, the layer-by-layer etching of the black chromium surface with argon gas was used. Analysis of XPS spectra has shown that the top layers of black chromium without zinc are composed of various Cr(III) components, organic substances and metallic Cr, whereas metallic Cr is almost absent in black chromium containing some amount of Zn(II) compounds. The ratios of metal/oxide phases were found to be 10/27 and 2/28 for black chromium without and with zinc, respectively. It has been determined that owing to the presence of ZnO in the Cr(III) bath, the percentage of metallic chromium is substantially reduced in black chromium which is quite important for good solar selective characteristics of the coating. The results confirm some of earlier observations and provide new information on the composition of the near-surface layers

  5. Sea spray aerosol chemical composition: elemental and molecular mimics for laboratory studies of heterogeneous and multiphase reactions.

    Science.gov (United States)

    Bertram, Timothy H; Cochran, Richard E; Grassian, Vicki H; Stone, Elizabeth A

    2018-04-03

    Sea spray aerosol particles (SSA), formed through wave breaking at the ocean surface, contribute to natural aerosol particle concentrations in remote regions of Earth's atmosphere, and alter the direct and indirect effects of aerosol particles on Earth's radiation budget. In addition, sea spray aerosol serves as suspended surface area that can catalyze trace gas reactions. It has been shown repeatedly that sea spray aerosol is heavily enriched in organic material compared to the surface ocean. The selective enrichment of organic material complicates the selection of representative molecular mimics of SSA for laboratory or computational studies. In this review, we first provide a short introduction to SSA formation processes and discuss chemical transformations of SSA that occur in polluted coastal regions and remote pristine air. We then focus on existing literature of the chemical composition of nascent SSA generated in controlled laboratory experiments and field investigations. We combine the evidence on the chemical properties of nascent SSA with literature measurements of SSA water uptake to assess SSA molecular composition and liquid water content. Efforts to speciate SSA organic material into molecular classes and specific molecules have led to the identification of saccharides, alkanes, free fatty acids, anionic surfactants, dicarboxylic acids, amino acids, proteinaceous matter, and other large macromolecules. However to date, less than 25% of the organic mass of nascent SSA has been quantified at a molecular level. As discussed here, quantitative measurements of size resolved elemental ratios, combined with determinations of water uptake properties, provides unique insight on the concentration of ions within SSA as a function of particle size, pointing to a controlling role for relative humidity and the hygroscopicity of SSA organic material at small particle diameters.

  6. Microstructural analysis of alumina chromium composites by X-ray tomography and 3-D finite element simulation of thermal stresses

    International Nuclear Information System (INIS)

    Geandier, G.; Hazotte, A.; Denis, S.; Mocellin, A.; Maire, E.

    2003-01-01

    X-ray microtomography is used to measure volume fraction and connectivity of the metallic phase in an alumina-chromium composite. Reconstructed images are used as input data for a finite element calculation of the residual thermal stresses. Results confirm the main trends shown by similar calculations previously performed on less-realistic finite element models

  7. Microstructural analysis of alumina chromium composites by X-ray tomography and 3-D finite element simulation of thermal stresses

    Energy Technology Data Exchange (ETDEWEB)

    Geandier, G.; Hazotte, A.; Denis, S.; Mocellin, A.; Maire, E

    2003-04-14

    X-ray microtomography is used to measure volume fraction and connectivity of the metallic phase in an alumina-chromium composite. Reconstructed images are used as input data for a finite element calculation of the residual thermal stresses. Results confirm the main trends shown by similar calculations previously performed on less-realistic finite element models.

  8. Parameterized Finite Element Modeling and Buckling Analysis of Six Typical Composite Grid Cylindrical Shells

    Science.gov (United States)

    Lai, Changliang; Wang, Junbiao; Liu, Chuang

    2014-10-01

    Six typical composite grid cylindrical shells are constructed by superimposing three basic types of ribs. Then buckling behavior and structural efficiency of these shells are analyzed under axial compression, pure bending, torsion and transverse bending by finite element (FE) models. The FE models are created by a parametrical FE modeling approach that defines FE models with original natural twisted geometry and orients cross-sections of beam elements exactly. And the approach is parameterized and coded by Patran Command Language (PCL). The demonstrations of FE modeling indicate the program enables efficient generation of FE models and facilitates parametric studies and design of grid shells. Using the program, the effects of helical angles on the buckling behavior of six typical grid cylindrical shells are determined. The results of these studies indicate that the triangle grid and rotated triangle grid cylindrical shell are more efficient than others under axial compression and pure bending, whereas under torsion and transverse bending, the hexagon grid cylindrical shell is most efficient. Additionally, buckling mode shapes are compared and provide an understanding of composite grid cylindrical shells that is useful in preliminary design of such structures.

  9. 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)

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

    International Nuclear Information System (INIS)

    Souza, Vitor I.; Saiki, Mitiko

    2015-01-01

    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)

  11. Base-line data on everglades soil-plant systems: elemental composition, biomass, and soil depth

    International Nuclear Information System (INIS)

    Volk, B.G.; Schemnitz, S.D.; Gamble, J.F.; Sartain, J.B.

    1975-01-01

    Plants and soils from plots in the Everglades Wildlife Management Area, Conservation Area 3, were examined. Chemical composition (N, P, K, Ca, Mg, Na, Cu, Fe, Mn, Zn, Co, Sr, Pb, Ni, Cr, Al, and Si) of most plant and soil digests was determined. Cladium jamaicense was the predominant plant species contributing to biomass in all plots except the wet prairie, where Rhynchospora sp. and Panicum hemitomon were most common. The biomass of dead C. jamaicense was greater than that of the living plants in unburned saw-grass plots. The burned saw grass, muck burn, and wet prairie were characterized by a large number of plant species per square meter but smaller average biomass production than the unburned saw-grass locations. Levels of Cu, Mn, Ca, Mg, K, and N in C. jamaicense differed significantly across locations. Highly significant differences in elemental composition existed between plant species. Concentrations of several elements (particularly Zn, Ca, Mg, P, and N) were low in live C. jamaicense compared with other plant species. Cesium-137 levels ranged from 670 to 3100 pCi/kg in sandy and in organic soils, respectively. Polygonum had a 137 Cs level of 11,600 pCi/kg. Dead C. jamaicense indicated a rapid leaching loss of 137 Cs from dead tissue

  12. Probabilistic homogenization of random composite with ellipsoidal particle reinforcement by the iterative stochastic finite element method

    Science.gov (United States)

    Sokołowski, Damian; Kamiński, Marcin

    2018-01-01

    This study proposes a framework for determination of basic probabilistic characteristics of the orthotropic homogenized elastic properties of the periodic composite reinforced with ellipsoidal particles and a high stiffness contrast between the reinforcement and the matrix. Homogenization problem, solved by the Iterative Stochastic Finite Element Method (ISFEM) is implemented according to the stochastic perturbation, Monte Carlo simulation and semi-analytical techniques with the use of cubic Representative Volume Element (RVE) of this composite containing single particle. The given input Gaussian random variable is Young modulus of the matrix, while 3D homogenization scheme is based on numerical determination of the strain energy of the RVE under uniform unit stretches carried out in the FEM system ABAQUS. The entire series of several deterministic solutions with varying Young modulus of the matrix serves for the Weighted Least Squares Method (WLSM) recovery of polynomial response functions finally used in stochastic Taylor expansions inherent for the ISFEM. A numerical example consists of the High Density Polyurethane (HDPU) reinforced with the Carbon Black particle. It is numerically investigated (1) if the resulting homogenized characteristics are also Gaussian and (2) how the uncertainty in matrix Young modulus affects the effective stiffness tensor components and their PDF (Probability Density Function).

  13. 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 ( Pacids (TAA), total essential amino acids (TEAA), total non-essential amino acids (TNEAA) and total delicious amino acids (TDAA) in farmed fish were all significantly higher than those in the wild equivalent ( Pacid 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 ( Pacid (PUFA) including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) than farmed fish ( Pacid (C18:2n6) were the predominant PUFA in wild and farmed C. mongolicus, respectively. Moreover, farmed fish displayed an overall lower toxic element 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.

  14. A fine surface roughness electroless Ni–P–PTFE composite modified stamper for light guide plate application

    International Nuclear Information System (INIS)

    Pan, K; Fu, C

    2010-01-01

    Electroless Ni–P–PTFE composite coating technology takes advantage of the beneficial properties from both Ni–P alloy and PTFE, such as good wear resistance, good anti-adhesion, dry lubrication, low coefficient of friction and good corrosion resistance. It has been applied in many mold industries. However, the Ni–P–PTFE composite coating suffers from bad surface roughness, when the PTFE particles incorporate into a Ni–P matrix. This severely hampers the technology to be applied to optical grade applications. In this paper, we propose a trick to generate a fine surface roughness (FSR) electroless Ni–P–PTFE composite to modify a nickel stamper. Using this new method, the nickel stamper can be covered by a Ni–P–PTFE functional layer and can keep the original surface property at the same time, namely the optical properties. We have chosen 4.5 inch (97 mm × 59 mm × 0.6 mm) light guide plates (LGPs) to demonstrate the effectiveness of the procedure. For the sake of comparison, the LGPs were produced by injection molding with three kinds of stampers including an original SUS430 master, an electroless Ni–P–PTFE composite coated nickel stamper and an FSR electroless Ni–P–PTFE composite modified stamper. We measured and discussed the optical performances at both the element level and system level, namely complete back light units.

  15. Characteristic Elemental Composition of Oil Pigments using Instrumental Neutron Activation Analysis

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Kim, Sun Ha; Sun, Gwang Min; Lim, Jong Myung; Moon, Jong Hwa; Kim, Young Jin; Lim, Sung Jin; Song, Yu Na; Kim, Ken

    2009-01-01

    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 3 ) 2 , PbSO 4 , PbO, Pb(OH) 2 , ZnO, ZnS, TiO 2 , BaSO 4 , CaCO 3 , Al 2 O 3 , As 2 S 3 , etc.; black pigments were series of carbon black, borne ash, MnO+Mn 2 O 3 , etc.; red pigments were Fe 2 O 3 , Pb 3 O 4 , HgS, PbMo 4 , CdS+CdSe, etc.; brown and yellow pigments were PbCrO 4 , ZnCrO 4 , CdS-ZnS, K 3 [Co(NO 2 ) 6 ], Pb(SbO 3 ) 2 , C 19 H 16 O 11 Mg, SrCrO 4 , etc.; green pigments were Cr 2 O 3 , Cr 2 O(OH) 4 , Cu(C 2 H 3 O 2 )-2Cu(OH) 2 ), Cr 2 O 3 -Al 2 O 3 -CoO, etc.; blue pigments were Fe 4 [Fe(CN) 6 ] 3 , CoO-Al 2 O 3 , Na 8 - 10 Al 6 Si 6 O 24 S 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 non-destructive, simultaneously multi-elemental analysis with high accuracy and sensitivity. In order to characterize the elemental contents of art objects, the quantitative analysis of oil pigment series was

  16. Element composition of biota, water and sediment in the Forsmark area, Baltic Sea. Concentrations, bioconcentration factors and partitioning coefficients (Kd) of 48 elements

    International Nuclear Information System (INIS)

    Kumblad, Linda; Bradshaw, Clare

    2008-08-01

    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 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 differences

  17. 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

  18. Surface segregation of low-Z elements on plasma-facing materials

    International Nuclear Information System (INIS)

    Qian Jiapu; Liu Xiang

    1994-10-01

    Surface segregation behavior of low-Z elements, e.g., lithium and beryllium on ternary alloy Al-Li-Mg and Binary alloy Cu-Be has been observed. The experiments were performed by means of Secondary Ion Mass Spectroscopy (SIMS) and Auger Electron Spectroscopy (AEA). The experimental results of Al-Li-Mg alloy indicated that lithium concentration on the specimen surface reached approximately 100% in the temperature range of 150 to 300 degree C, which can be explained by Gibbsian segregation theory. The depth profile of Li showed that there was some broadening resulting from recoil implantation by high energy Ar ion bombardment. When the specimen temperature exceeded 360 degree C, beryllium, the impurity element in the alloy was found to segregate to the surface. For this reason, another experiment on surface segregation of Cu-Be alloy was carried out by SIMS and AES, the surface analysis utilizing in-situ AES analysis revealed that the surface was enriched by Be and O at elevated temperature, considering the chemical affinity of Be and O, the principal driving force of segregation was attributed to the oxygen partial pressure in the atmosphere. The depth profile of Be in the alloy was also investigated. (9 figs.)

  19. Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations

    International Nuclear Information System (INIS)

    Fischer, Cornelius; Karius, Volker; Luettge, Andreas

    2009-01-01

    Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th, and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F. This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements.

  20. Correlation between sub-micron surface roughness of iron oxide encrustations and trace element concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Cornelius, E-mail: cornelius@rice.edu [Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Geowissenschaftliches Zentrum der Universitaet Goettingen, Abt. Sedimentologie and Umweltgeologie, Goldschmidtstr. 3, D-37077 Goettingen (Germany); Karius, Volker [Geowissenschaftliches Zentrum der Universitaet Goettingen, Abt. Sedimentologie and Umweltgeologie, Goldschmidtstr. 3, D-37077 Goettingen (Germany); Luettge, Andreas [Department of Earth Science, MS-126, Rice University, 6100 Main Street, Houston, TX 77005 (United States); Department of Chemistry, Rice University, 6100 Main Street, Houston, TX 77005 (United States)

    2009-08-01

    Iron oxide encrustations are formed on black slate surfaces during oxidative weathering of iron sulfide and phosphate bearing, organic matter-rich slates. Synchronously, trace elements are released during ongoing weathering. Laser ablation ICP-MS analyses of a weathered and encrusted slate showed that major portions of the V, Cu, As, Mo, Pb, Th, and U reside in the encrustation. Recently a potential relationship between several micrometer to 500 nm surface topography roughness of such encrustations and its uranium concentration was shown. Based on laser scanning microscopy measurements, the present study shows that this interrelation must be expanded to small submicron-sized half-pores with diameters between 100 nm and 500 nm. We demonstrate that the relationship is not limited to topography variations of a single encrustation in the hand-specimen scale. Surface topography and geochemical analyses of iron oxide encrustations from several locations but from the same geochemical environment and with similar weathering history showed that the concentrations of U, P, Cu, and Zn correlate inversely with the surface roughness parameter F. This parameter represents the total surface area and is - in this case - a proxy for the root-mean square surface roughness Rq. This study substantiates the environmental importance that micrometer- to submicrometer topography variations of fluid-rock interfaces govern the trapping of trace elements.

  1. Effective attenuation lengths for quantitative determination of surface composition by Auger-electron spectroscopy and X-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Jablonski, A.; Powell, C.J.

    2017-01-01

    Highlights: • Effective attenuation lengths (EALs) for determination of surface composition by XPS. • Considerable difference from EALs used for overlayer thickness measurements. • New analytical algorithms for calculating the effective attenuation length. - Abstract: The effective attenuation length (EAL) is normally used in place of the inelastic mean free path (IMFP) to account for elastic-scattering effects when describing the attenuation of Auger electrons and photoelectrons from a planar substrate by an overlayer film. An EAL for quantitative determination of surface composition by Auger-electron spectroscopy (AES) or X-ray photoelectron spectroscopy (XPS) is similarly useful to account for elastic-scattering effects on the signal intensities. We calculated these EALs for four elemental solids (Si, Cu, Ag, and Au) and for energies between 160 eV and 1.4 keV. The XPS calculations were made for two instrumental configurations while the AES calculations were made from the XPS formalism after “switching off” the XPS anisotropy. The EALs for quantitative determination of surface composition by AES and XPS were weak functions of emission angle for emission angles between 0 and 50°. The ratios of the average values of these EALs to the corresponding IMFPs could be fitted to a second-order function of the single-scattering albedo, a convenient measure of the strength of elastic-scattering effects. EALs for quantitative determination of surface composition by AES and XPS for other materials can be simply found from this relationship.

  2. Adhesion enhancement of Al coatings on carbon/epoxy composite surfaces by atmospheric plasma

    International Nuclear Information System (INIS)

    Coulon, J.F.; Tournerie, N.; Maillard, H.

    2013-01-01

    Adhesion strengths between aluminium thin film coatings and manufactured carbon/epoxy composite surfaces were measured by assessing fracture tensile strengths using pull-off tests. The effect of the substrate roughness (nm to μm) of these composite surfaces on adhesion was studied by examining the surface free energies and adhesion strengths. The adhesion strengths of the coatings varied significantly. To improve the coating adhesion, each composite surface was treated with atmospheric plasma prior to deposition, which resulted in an increase in the surface free energy from approximately 40 mJ/m 2 to 70 mJ/m 2 because the plasma pretreatment led to the formation of hydrophilic C-O and C=O bonds on the composite surfaces, as demonstrated by X-ray photoelectron spectroscopy analyses. The adhesion strengths of the coatings were enhanced for all surface roughnesses studied. In our study, the effect of mechanical adhesion due to roughness was separated from the effect of modifying the chemical bonds with plasma activation. The adhesion ability of the pure resin was relatively weak. Increasing the surface roughness largely improved the adhesion of the resin surface. Plasma treatment of the pure resin also increased the surface adhesion. Our study shows that plasma activation effectively enhances the adhesion of manufactured composites, even when the surface roughness is on the order of microns. The ageing of the surface activation was also investigated, and the results demonstrate that atmospheric plasma has potential for use in the pretreatment of composite materials.

  3. SAFE-AXISYM, Stress Analysis of Axisymmetric Composite Structure by Finite Elements Method

    International Nuclear Information System (INIS)

    Cornell, D.C.

    1967-01-01

    1 - Nature of physical problem solved: SAFE-AXISYM is a program for the analysis of multi-material axisymmetric composite structures. It is designed for the analysis of heterogeneous structures such as reinforced and/or prestressed concrete vessels. The structure is assumed to be linearly elastic, and only bodies of revolution subjected to axisymmetric loading can be treated. 2 - Method of solution: SAFE-AXISYM uses a finite element method with a modified Gauss-Seidel iteration scheme. A reference grid subdivides the structure into ring-like small, finite elements, the vertices of which are called nodes. The grid may be generated by hand, by the computer or by a combination of the two methods. Each node has two degrees of freedom, translation in the and in the axial direction. Both zero and non-zero fixed displacement constraints may be assumed, and the loading condition may be mechanical and/or thermal. 3 - Restrictions on the complexity of the problem: Multi-material structures with varying rigidities converge very slowly. Not valid for incompressible materials. Maximum number of nodes = 475. Maximum number of elements = 1100

  4. Determination of elemental composition of metals using ambient organic mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Shiea, Christopher [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Huang, Yeou-Lih [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd, Kaohsiung 804, Taiwan (China); Cheng, Sy-Chyi; Chen, Yi-Lun [Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd, Kaohsiung 804, Taiwan (China); Shiea, Jentaie, E-mail: jetea@mail.nsysu.edu.tw [Department of Chemistry, National Sun Yat-Sen University, 70 Lien-Hai Rd, Kaohsiung 804, Taiwan (China); Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China)

    2017-05-22

    Conventional inorganic mass spectrometric (MS) analysis of metals can require time-consuming and tedious sample preparation. We thus report the novel and direct characterization of metals in solid samples using an organic MS technique known as electrospray laser desorption ionization mass spectrometry (ELDI/MS). No sample pretreatment was needed, and results were rapidly obtained due to the ambient and laser-based nature of ELDI/MS. Metals from samples were desorbed and ionized by laser irradiation, after which they reacted with EDTA and then post-ionized and detected as metal-EDTA complexes. Aluminum, copper, iron, lead, nickel, and zinc from plates, foils, and coins were characterized in seconds. This study demonstrates that an ESI/MS system can be easily modified to analyze metal elements in solids by involving a chelating agent, indicating a potentially promising development in MS towards the analysis of metals using organic MS. - Highlights: • “Organic MS” was utilized as “inorganic MS” to detect metal ions in solid samples. • Element ions desorbed by laser irradiation rapidly reacted with a chelating reagent before they were detected by MS. • Elemental composition of metals was determined by this “Organic MS” method.

  5. Determination of elemental composition of metals using ambient organic mass spectrometry

    International Nuclear Information System (INIS)

    Shiea, Christopher; Huang, Yeou-Lih; Cheng, Sy-Chyi; Chen, Yi-Lun; Shiea, Jentaie

    2017-01-01

    Conventional inorganic mass spectrometric (MS) analysis of metals can require time-consuming and tedious sample preparation. We thus report the novel and direct characterization of metals in solid samples using an organic MS technique known as electrospray laser desorption ionization mass spectrometry (ELDI/MS). No sample pretreatment was needed, and results were rapidly obtained due to the ambient and laser-based nature of ELDI/MS. Metals from samples were desorbed and ionized by laser irradiation, after which they reacted with EDTA and then post-ionized and detected as metal-EDTA complexes. Aluminum, copper, iron, lead, nickel, and zinc from plates, foils, and coins were characterized in seconds. This study demonstrates that an ESI/MS system can be easily modified to analyze metal elements in solids by involving a chelating agent, indicating a potentially promising development in MS towards the analysis of metals using organic MS. - Highlights: • “Organic MS” was utilized as “inorganic MS” to detect metal ions in solid samples. • Element ions desorbed by laser irradiation rapidly reacted with a chelating reagent before they were detected by MS. • Elemental composition of metals was determined by this “Organic MS” method.

  6. Effect of Impact Angle on Ceramic Deposition Behavior in Composite Cold Spray: A Finite-Element Study

    Science.gov (United States)

    Chakrabarty, Rohan; Song, Jun

    2017-10-01

    During the cold spraying of particle-reinforced metal matrix composite coatings (ceramic and metal particles mixture) on metal substrates, ceramic particles may either get embedded in the substrate/deposited coating or may rebound from the substrate surface. In this study, the dependence of the ceramic rebounding phenomenon on the spray angle and its effect on substrate erosion have been analyzed using finite-element analysis. From the numerical simulations, it was found that the ceramic particle density and substrate material strength played the major roles in determining the embedding and ceramic retention behavior. Substrate material erosion also influenced the ceramic retention, and the material loss increased as the impact angles decreased from normal. In general, the results concluded that decreasing the impact angle promoted the retention possibility of ceramics in the substrate. This study provides new theoretical insights into the effect of spray angles on the ceramic retention and suggests a new route toward optimizing the spraying process to increase the ceramic retention in composite coatings cold spray.

  7. SRXFA in the studies of the correlation between the element composition of human blood and environment objects

    Science.gov (United States)

    Koutzenogii, K. P.; Savchenko, T. I.; Chankina, O. V.; Popova, S. A.

    2009-05-01

    High correlation has been revealed both between the content of chemical elements in human blood and atmospheric aerosols and between blood elements and food components. The element compositions of blood and hair have been established to be strongly related to each other. These biosubstrates can be used to estimate the health of the population of the northern hemisphere. Variability of the multielement composition of the blood and hair of the inhabitants of Novosibirsk, the Tundra Nenetz, Yakuts, Chukchi and the Eskimos, food components and aerosols in the regions where they live was determined by the SRXFA method.

  8. 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.

  9. Remote compositional mapping of lunar titanium and surface maturity

    Science.gov (United States)

    Johnson, J. R.; Larson, S. M.; Singer, Robert B.

    1991-01-01

    Lunar ilmenite (FeTiO3) is a potential resource capable of providing oxygen for life support and spacecraft propellant for future lunar bases. Estimates of TiO2 content in mature mare soils can be made using an empirical relation between the 400/500 nm reflectance ratio and TiO2 wt percent. A TiO2 abundance map was constructed for the entire near-side lunar maria accurate to + or - 2 wt percent TiO2 using CCD images obtained at the Tumamoc Hill 0.5 m telescope in Tucson, employing bandpass filters centered at 400 and 560 nm. Highest TiO2 regions in the maria are located in western Mare Tranquillitatis. Greater contrast differences between regions on the lunar surface can be obtained using 400/730 nm ratio images. The relation might well be refined to accommodate this possibly more sensitive indicator of TiO2 content. Another potential lunar resource is solar wind-implanted He-3 which may be used as a fuel for fusion reactors. Relative soil maturity, as determined by agglutinate content, can be estimated from 950/560 nm ration images. Immature soils appear darker in this ratio since such soils contain abundant pyroxene grains which cause strong absorption centered near 950 nm due Fe(2+) crystal field transitions. A positive correlation exists between the amount of He-3 and TiO2 content in lunar soils, suggesting that regions high in TiO2 should also be high in He-3. Reflectance spectrophotometry in the region 320 to 870 nm was also obtained for several regions. Below about 340 nm, these spectra show variations in relative reflectance that are caused by as yet unassigned near-UV absorptions due to compositional differences.

  10. Galileo's Multiinstrument Spectral View of Europa's Surface Composition

    Science.gov (United States)

    Fanale, F.P.; Granahan, J.C.; McCord, T.B.; Hansen, G.; Hibbitts, C.A.; Carlson, R.; Matson, D.; Ocampo, A.; Kamp, L.; Smythe, W.; Leader, F.; Mehlman, R.; Greeley, R.; Sullivan, R.; Geissler, P.; Barth, C.; Hendrix, A.; Clark, B.; Helfenstein, P.; Veverka, J.; Belton, M.J.S.; Becker, K.; Becker, T.

    1999-01-01

    We have combined spectral reflectance data from the Solid State Imaging (SSI) experiment, the Near-Infrared Mapping Spectrometer (NIMS), and the Ultraviolet Spectrometer (UVS) in an attempt to determine the composition and implied genesis of non-H2O components in the optical surface of Europa. We have considered four terrains: (1) the "dark terrains" on the trailing hemisphere, (2) the "mottled terrain," (3) the linea on the leading hemisphere, and (4) the linea embedded in the dark terrain on the trailing hemisphere. The darker materials in these terrains exhibit remarkably similar spectra in both the visible and near infrared. In the visible, a downturn toward shorter wavelengths has been attributed to sulfur. The broad concentrations of dark material on the trailing hemisphere was originally thought to be indicative of exogenic sulfur implantation. While an exogenic cause is still probable, more recent observations by the UVS team at higher spatial resolution have led to their suggestions that the role of the bombardment may have primarily been to sputter away overlying ice and to reveal underlying endogenic non-H2O contaminants. If so, this might explain why the spectra in all these terrains are so similar despite the fact that the contaminants in the linea are clearly endogenic and those in the mottled terrain are almost certainly so. In the near infrared, all these terrains exhibit much more asymmetrical bands at 1.4 and 2.0 ??m at shorter wavelengths than spectra from elsewhere on Europa. It has been argued that this is because the water molecules are bound in hydrated salts. However, this interpretation has been challenged and it has also been argued that pure coarse ice can exhibit such asymmetric bands under certain conditions. The nature of this controversy is briefly discussed, as are theoretical and experimental studies bearing on this problem. ?? 1999 Academic Press.

  11. Weathering of the New Albany Shale, Kentucky, USA: I. Weathering zones defined by mineralogy and major-element composition

    Science.gov (United States)

    Tuttle, M.L.W.; Breit, G.N.

    2009-01-01

    Comprehensive understanding of chemical and mineralogical changes induced by weathering is valuable information when considering the supply of nutrients and toxic elements from rocks. Here minerals that release and fix major elements during progressive weathering of a bed of Devonian New Albany Shale in eastern Kentucky are documented. Samples were collected from unweathered core (parent shale) and across an outcrop excavated into a hillside 40 year prior to sampling. Quantitative X-ray diffraction mineralogical data record progressive shale alteration across the outcrop. Mineral compositional changes reflect subtle alteration processes such as incongruent dissolution and cation exchange. Altered primary minerals include K-feldspars, plagioclase, calcite, pyrite, and chlorite. Secondary minerals include jarosite, gypsum, goethite, amorphous Fe(III) oxides and Fe(II)-Al sulfate salt (efflorescence). The mineralogy in weathered shale defines four weathered intervals on the outcrop-Zones A-C and soil. Alteration of the weakly weathered shale (Zone A) is attributed to the 40-a exposure of the shale. In this zone, pyrite oxidization produces acid that dissolves calcite and attacks chlorite, forming gypsum, jarosite, and minor efflorescent salt. The pre-excavation, active weathering front (Zone B) is where complete pyrite oxidation and alteration of feldspar and organic matter result in increased permeability. Acidic weathering solutions seep through the permeable shale and evaporate on the surface forming abundant efflorescent salt, jarosite and minor goethite. Intensely weathered shale (Zone C) is depleted in feldspars, chlorite, gypsum, jarosite and efflorescent salts, but has retained much of its primary quartz, illite and illite-smectite. Goethite and amorphous FE(III) oxides increase due to hydrolysis of jarosite. Enhanced permeability in this zone is due to a 14% loss of the original mass in parent shale. Denudation rates suggest that characteristics of Zone C

  12. Finite element analysis when orthogonal cutting of hybrid composite CFRP/Ti

    International Nuclear Information System (INIS)

    Xu, Jinyang; Mansori, Mohamed El

    2015-01-01

    Hybrid composite, especially CFRP/Ti stack, is usually considered as an innovative structural configuration for manufacturing the key load-bearing components in modern aerospace industry. This paper originally proposed an FE model to simulate the total chip formation process dominated the hybrid cutting operation. The hybrid composite model was established based on three physical constituents, i.e., Ti constituent, interface and CFRP constituent. Different constitutive models and damage criteria were introduced to replicate the interrelated cutting behaviour of the stack material. The CFRP/Ti interface was modelled as a third phase through the concept of cohesive zone (CZ). Particular attention was made on the comparative studies of the influence of different cutting-sequence strategies on the machining responses induced in hybrid stack cutting. The numerical results emphasized the pivotal role of cutting-sequence strategy on the various machining induced responses including cutting-force generation, machined surface quality and induced interface damage. (paper)

  13. 3D finite element model of elastoplastic contact on the double sinus rough surface

    International Nuclear Information System (INIS)

    Hagege, H; Bouvier, S; Mazeran, P-E; Bigerelle, M

    2011-01-01

    One of the objectives in the field of tribology is to solve the mechanical stress-displacement problem involved by rough contacts. In our approach, the surface chosen is a 256-256 μm 2 3D sinusoidal shape (amplitude 4.5μm, wavelength 50μm) with an elastoplastic constitutive behaviour. The constitutive law combines isotropic and kinematic hardening and is experimentally identified from 316L steel sheets. The FEM deformable surface is crushed then uncrushed by a rigid flat surface: stresses, contact pressure and plastic cumulated strain are computed. We investigate the results sensitivity with respect to the level of in-plane refinement. At last, we conclude on some guidelines for 3D finite elements modelling of rough surfaces.

  14. A mechanical model for surface layer formation on self-lubricating ceramic composites

    NARCIS (Netherlands)

    Song, Jiupeng; Valefi, Mahdiar; de Rooij, Matthias B.; Schipper, Dirk J.

    2010-01-01

    To predict the thickness of a self-lubricating layer on the contact surface of ceramic composite material containing a soft phase during dry sliding test, a mechanical model was built to calculate the material transfer of the soft second phase in the composite to the surface. The tribological test,

  15. Influence of surface roughness on streptococcal adhesion forces to composite resins

    NARCIS (Netherlands)

    Mei, Li; Busscher, Henk J; van der Mei, Henny C; Ren, Yijin

    OBJECTIVE: To determine streptococcal adhesion forces with composite resins with different surface roughness. METHODS: Polishing and grinding were applied to obtain smooth (roughness 20 nm), moderately rough (150 nm) and rough (350 nm) surfaces of two orthodontic, light-cured composites. Adhesion

  16. Analysis of asphalt mix surface-tread rubber interaction by using finite element method

    Directory of Open Access Journals (Sweden)

    Santosh Kumar Srirangam

    2017-08-01

    Full Text Available The surface texture of the pavement plays a very important role in driving the frictional properties at the tire rubber-pavement interface. Particularly, the hysteretic friction due to viscoelastic deformations of rubber depends mainly on the pavement surface texture. In the present paper, the effect of micromechanical pavement surface morphology on rubber block friction was brought in by comparing the friction results for three different asphalt mix morphological surfaces, named stone mastic asphalt (SMA, ultra-thin surfacing (UTS and porous asphalt (PA. The asphalt surface morphologies of these mixes were captured by using an X-ray tomographer, from which the resulting images micromechanical finite element (FE meshes for SMA, UTS and PA pavements were developed by means of the SimpleWare software. In the FE model, the rubber and asphalt binder were modeled as viscoelastic (VE materials and the formulation was given in the large deformation framework. FE simulations were then carried out by using contact algorithm between rubber and the road surface. It was observed that the rubber friction inversely varies with the sliding speed and positively varies with the pressure for all the pavement morphological and stiffness conditions. Furthermore, it was observed that the highly porous pavement surface results in large dissipation of energy, hence, large rubber friction which shows that the mix characteristics of pavements have a significant effect on rubber friction.

  17. Robust and efficient handling of yield surface discontinuities in elasto-plastic finite element calculations

    DEFF Research Database (Denmark)

    Clausen, Johan Christian; Damkilde, Lars; Andersen, Lars Vabbersgaard

    2015-01-01

    Purpose – The purpose of this paper is to present several methods on how to deal with yield surface discontinuities. The explicit formulations, first presented by Koiter (1953), result in multisingular constitutive matrices which can cause numerical problems in elasto-plastic finite element...... documented in the literature all present “easy” calculation examples, e.g. low friction angles and few elements. The amendments presented in this paper result in robust elasto-plastic computations, making the solution of “hard” problems possible without introducing approximations in the yield surfaces...... calculations. These problems, however, are not documented in previous literature. In this paper an amendment to the Koiter formulation of the constitutive matrices for stress points located on discontinuities is proposed. Design/methodology/approach – First, a review of existing methods of handling yield...

  18. Elemental composition of air masses under different altitudes in Azores, central north Atlantic

    International Nuclear Information System (INIS)

    Vieira, B.J.; Wolterbeek, H.Th.

    2012-01-01

    Between 8th July 2002 and 18th June 2004, aerosol samples were collected in Azores. Their inorganic composition was obtained by neutron activation analysis in order to study the differences of aerosols in two atmospheric altitudes of the central north Atlantic: (1) PICO-NARE observatory (Lower Free Troposphere-LFT) at Pico mountain summit (38,470 deg N, 28,404 deg W, 2,225 m a.s.l.) in Pico Island, Azores, where air masses from the surrounding continents (Africa, Europe, Central and North America) pass through, carrying aerosols with anthropogenic (Sb, Br, Mo, U, Se and Tb) and/or natural emissions (Fe, Co, La, Na, Sm, Cr, Zn, Hf, K and Th); (2) TERCEIRA-NARE station (Marine Boundary Layer) at Serreta (38,69 deg N, 27,36 deg W, 50 m a.s.l.), in Terceira Island, Azores, where natural aerosols (I, Cl, Na, Br and other soil related elements) are predominant. However, a combined interpretation of the data points out to a co-existence of the anthropogenic elements Sb and Mo, eventually with similar origins as the ones passing Pico Mountain summit. Very high concentrations and enrichment factors for Sb, Mo and Br in LFT, higher than the ones found in other areas, confirm atmospheric long-range transport mainly from the west boundary of north Atlantic; this may indicate eventual accumulation and persistence of those elements in the area due to the presence of Azores high pressures or the Hadley cells effect. A significant correlation between Fe and Yb and the enrichment of rare earth elements (La, Sm, Tb and Yb) and Th in LFT aerosols, both reflect a mineral dust intrusions from north Africa (Sahara and Sahel region). (author)

  19. 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

  20. Elemental composition of airborne particles in a Montevideo zone of Uruguay

    International Nuclear Information System (INIS)

    Odino, R.; Gabrielli, A.; Piuma, L.; Reina, E.; Suarez, R.

    2010-01-01

    Due to the impact on the population with air quality, it is important to identify and quantify the chemical elements present in the fractions of air particulate matter P M 10 and Pm 2.5. In the present study considers the effect of interference caused by ash from the volcano Puyehue in monitoring air particulate matter started in Nairobi in February 2011. We used a dichotomous Andersen sampler and polycarbonate filters exposed for 24 hours. We analyzed the elemental composition of the fractions P M 2.5 and P M 10 in approximately 100 nucleo pore membranes using fluorescence X-ray energy dispersive (EDXRF). Membranes were measured fraction P M 2.5 by reflectometry to estimate the concentration of Carbon Black. We analyzed the following elements: Al, Si, S, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, As, Sr, Ba, Pb. On the results obtained are applied principal component analysis (Pca) using SPSS statistical tool. It was observed that the V and S are associated mainly to the P M 2.5 and the average values ??of Pb and particulate matter P M 2.5 and P M 10 are below the levels recommended by EPA prior to the event associated with the eruption of volcano. Emission sources were identified that correspond to land, traffic, power plant and oil refinery. An increase of Si, Ca, Al, Fe and Sr in the P M 10 in the days when it was reported in Montevideo presence of ash caused by the volcano. Also sedimented dust collected was analyzed by EDXRF. The results of elemental chemical analysis carried out in the dust settled show a good correlation with the results of analysis performed on the filters in the days when we observed the incident. Sedimented dust was analyzed by High Resolution Gamma Spectrometry. They detected the presence of 7Be caused by the interaction of dust with cosmic ray protons. [es

  1. Free surface simulation of a two-layer fluid by boundary element method

    Directory of Open Access Journals (Sweden)

    Weoncheol Koo

    2010-09-01

    Full Text Available A two-layer fluid with free surface is simulated in the time domain by a two-dimensional potential-based Numerical Wave Tank (NWT. The developed NWT is based on the boundary element method and a leap-frog time integration scheme. A whole domain scheme including interaction terms between two layers is applied to solve the boundary integral equation. The time histories of surface elevations on both fluid layers in the respective wave modes are verified with analytic results. The amplitude ratios of upper to lower elevation for various density ratios and water depths are also compared.

  2. Study on the state of a surface of compounds of vanadium with light elements

    International Nuclear Information System (INIS)

    Povstugar, V.I.; Mikhajlova, S.S.; Trapeznikov, V.A.

    1976-01-01

    Roentgenoelectron study of powderlike compounds of vanadium with light elements (C, N, O, S) was carried out. The study was made in the temperature range of 70-500 deg C. The results were obtained in an electron magnetic spectrometer. Spectra of inner levels O 1S and V 2p and valance bands are presented. The experimental results can be employed for the study of synthesis problems of the given class of compounds. Due to high surface activity the study of catalytic properties of finely dispersed vanadium compounds by roentgenoelectron spectroscopy method gives much information about surface processes

  3. Finite element method for starved hydrodynamic lubrication with film separation and free surface effects

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Vølund, Anders; Klit, Peder

    2018-01-01

    This paper proposes a numerical method for determining the evolution of lubricant film thickness and pressure in partially and fully flooded regions of a hydrodynamic contact between two non-conformal rigid surfaces. The proposed method accounts for the classical Reynolds equation within the fully...... thickness is zero. Both pressure and film thickness fields are considered as unknowns to solve for in each time step and they are approximated through quadratic B-spline finite elements. The geometry of the gap between the rigid surfaces delimiting the lubricant is accounted for in the form of a unilateral...

  4. Evaluation of crack interaction effect for in-plane surface cracks using elastic finite element analyses

    International Nuclear Information System (INIS)

    Huh, Nam Su; Choi, Suhn; Park, Keun Bae; Kim, Jong Min; Choi, Jae Boong; Kim, Young Jin

    2008-01-01

    The crack-tip stress fields and fracture mechanics assessment parameters, such as the elastic stress intensity factor and the elastic-plastic J-integral, for a surface crack can be significantly affected by adjacent cracks. Such a crack interaction effect due to multiple cracks can magnify the fracture mechanics assessment parameters. There are many factors to be considered, for instance the relative distance between adjacent cracks, crack shape and loading condition, to quantify a crack interaction effect on the fracture mechanics assessment parameters. Thus, the current guidance on a crack interaction effect (crack combination rule), including ASME Sec. XI, BS7910, British Energy R6 and API RP579, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates a crack interaction effect by evaluating the elastic stress intensity factor of adjacent surface cracks in a plate along the crack front through detailed 3-dimensional elastic finite element analyses. The effects of the geometric parameters, the relative distance between cracks and the crack shape, on the stress intensity factor are systematically investigated. As for the loading condition, only axial tension is considered. Based on the elastic finite element results, the acceptability of the crack combination rules provided in the existing guidance was investigated, and the relevant recommendations on a crack interaction for in-plane surface cracks in a plate were discussed

  5. Transport and dispersion of pollutants in surface impoundments: a finite element model

    International Nuclear Information System (INIS)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied

  6. Transport and dispersion of pollutants in surface impoundments: a finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, G.T.

    1980-07-01

    A surface impoundment model in finite element (SIMFE) is presented to enable the simulation of flow circulations and pollutant transport and dispersion in natural or artificial lakes, reservoirs or ponds with any number of islands. This surface impoundment model consists of two sub-models: hydrodynamic and pollutant transport models. Both submodels are simulated by the finite element method. While the hydrodynamic model is solved by the standard Galerkin finite element scheme, the pollutant transport model can be solved by any of the twelve optional finite element schemes built in the program. Theoretical approximations and the numerical algorithm of SIMFE are described. Detail instruction of the application are given and listing of FORTRAN IV source program are provided. Two sample problems are given. One is for an idealized system with a known solution to show the accuracy and partial validation of the models. The other is applied to Prairie Island for a set of hypothetical input data, typifying a class of problems to which SIMFE may be applied.

  7. Influence of polishing on surface roughness following toothbrushing wear of composite resins.

    Science.gov (United States)

    Dalla-Vecchia, Karine Battestin; Taborda, Talita Damas; Stona, Deborah; Pressi, Heloísa; Burnett Júnior, Luiz Henrique; Rodrigues-Junior, Sinval Adalberto

    2017-01-01

    This study aimed to evaluate the influence of different polishing systems on the surface roughness of composite resins following procedures to simulate the effects of toothbrushing over time. Four currently available commercial composites were used to make 128 cylindrical specimens. The specimens were randomly allocated to polishing with a 1-step polisher or 1 of 3 multistep polishers (n = 8 per group). The baseline surface roughness was measured, and the specimens were submitted to 5000, 10,000, and 20,000 brushing cycles to represent toothbrushing throughout 6, 12, and 24 months, respectively. Results showed that surface roughness was influenced by the type of composite and polishing system and was not influenced by the simulated toothbrushing time. However, the surface roughness, as challenged by toothbrushing wear, was affected by the interaction among the composite, the polisher, and the toothbrushing time. The 1-step polisher produced the highest surface roughness and influenced toothbrushing wear resistance of some composites.

  8. Photoelectron binding energy shifts observed during oxidation of group IIA, IIIA and IVA elemental surfaces

    International Nuclear Information System (INIS)

    Heide, P.A.W. van der

    2006-01-01

    An extensive re-evaluation of XPS binding energies (BE's) and binding energy shifts (ΔBE's) from metals, oxides and the carbonates of the group II, III and IVA elements (exceptions are Be, Mg and Hf) has been carried out using a substrate specific BE referencing approach. From this, O-1s BE's are found to fall into surface oxide, bulk oxide and carbonate groupings, with bulk oxides showing the lowest BE's followed by surface oxides (+∼1.5 eV) and then carbonates (+∼3.0 eV). The O-1s BE's from the bulk oxides also appear to scale with 1/d, where d is inter-atomic distance. The same is noted in the ΔBE's observed from the metallic counterparts during oxidation of the elemental surfaces. This, and the decreasing BE exhibited by Ca, Sr and Ba on oxidation is explained within the charge potential model as resulting from competing inter- and intra-atomic effects, and is shown to be consistent with partial covalency arguments utilizing Madulung potentials. The ΔBE's also fall into groups according to the elements location in the periodic table, i.e. s, p or d block. These trends open up the possibility of approximating ΔBE's arising from initial and final state effects, and bond distances

  9. The three-dimensional elemental distribution based on the surface topography by confocal 3D-XRF analysis

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Longtao; Qin, Min; Wang, Kai; Peng, Shiqi; Sun, Tianxi; Liu, Zhiguo [Beijing Normal University, College of Nuclear Science and Technology, Beijing (China); Lin, Xue [Northwest University, School of Cultural Heritage, Xi' an (China)

    2016-09-15

    Confocal three-dimensional micro-X-ray fluorescence (3D-XRF) is a good surface analysis technology widely used to analyse elements and elemental distributions. However, it has rarely been applied to analyse surface topography and 3D elemental mapping in surface morphology. In this study, a surface adaptive algorithm using the progressive approximation method was designed to obtain surface topography. A series of 3D elemental mapping analyses in surface morphology were performed in laboratories to analyse painted pottery fragments from the Majiayao Culture (3300-2900 BC). To the best of our knowledge, for the first time, sample surface topography and 3D elemental mapping were simultaneously obtained. Besides, component and depth analyses were also performed using synchrotron radiation confocal 3D-XRF and tabletop confocal 3D-XRF, respectively. The depth profiles showed that the sample has a layered structure. The 3D elemental mapping showed that the red pigment, black pigment, and pottery coat contain a large amount of Fe, Mn, and Ca, respectively. From the 3D elemental mapping analyses at different depths, a 3D rendering was obtained, clearly showing the 3D distributions of the red pigment, black pigment, and pottery coat. Compared with conventional 3D scanning, this method is time-efficient for analysing 3D elemental distributions and hence especially suitable for samples with non-flat surfaces. (orig.)

  10. The three-dimensional elemental distribution based on the surface topography by confocal 3D-XRF analysis

    International Nuclear Information System (INIS)

    Yi, Longtao; Qin, Min; Wang, Kai; Peng, Shiqi; Sun, Tianxi; Liu, Zhiguo; Lin, Xue

    2016-01-01

    Confocal three-dimensional micro-X-ray fluorescence (3D-XRF) is a good surface analysis technology widely used to analyse elements and elemental distributions. However, it has rarely been applied to analyse surface topography and 3D elemental mapping in surface morphology. In this study, a surface adaptive algorithm using the progressive approximation method was designed to obtain surface topography. A series of 3D elemental mapping analyses in surface morphology were performed in laboratories to analyse painted pottery fragments from the Majiayao Culture (3300-2900 BC). To the best of our knowledge, for the first time, sample surface topography and 3D elemental mapping were simultaneously obtained. Besides, component and depth analyses were also performed using synchrotron radiation confocal 3D-XRF and tabletop confocal 3D-XRF, respectively. The depth profiles showed that the sample has a layered structure. The 3D elemental mapping showed that the red pigment, black pigment, and pottery coat contain a large amount of Fe, Mn, and Ca, respectively. From the 3D elemental mapping analyses at different depths, a 3D rendering was obtained, clearly showing the 3D distributions of the red pigment, black pigment, and pottery coat. Compared with conventional 3D scanning, this method is time-efficient for analysing 3D elemental distributions and hence especially suitable for samples with non-flat surfaces. (orig.)

  11. Modeling and computation of two phase geometric biomembranes using surface finite elements

    OpenAIRE

    Elliott, Charles M.; Stinner, Björn

    2010-01-01

    Biomembranes consisting of multiple lipids may involve phase separation phenomena leading to coexisting domains of different lipid compositions. The modeling of such biomembranes involves an elastic or bending energy together with a line energy associated with the phase interfaces. This leads to a free boundary problem for the phase interface on the unknown equilibrium surface which minimizes an energy functional subject to volume and area constraints. In this paper we propose a new computati...

  12. Examination of the surface coatings removed from K-East Basin fuel elements

    International Nuclear Information System (INIS)

    Abrefah, J.; Marschman, S.C.; Jenson, E.D.

    1998-05-01

    This report provides the results of studies conducted on coatings discovered on the surfaces of some N-Reactor spent nuclear fuel (SNF) elements stored at the Hanford K-East Basin. These elements had been removed from the canisters and visually examined in-basin during FY 1996 as part of a series of characterization tests. The characterization tests are being performed to support the Integrated Process Strategy developed to package, dry, transport, and store the SNF in an interim storage facility on the Hanford site. Samples of coating materials were removed from K-East canister elements 2350E and 2540E, which had been sent, along with nine other elements, to the Postirradiation Testing Laboratory (327 Building) for further characterization following the in-basin examinations. These coating samples were evaluated by Pacific Northwest National Laboratory using various analytical methods. This report is part of the overall studies to determine the drying behavior of corrosion products associated with the K-Basin fuel elements. Altogether, five samples of coating materials were analyzed. These analyses suggest that hydration of the coating materials could be an additional source of moisture in the Multi-Canister Overpacks being used to contain the fuel for storage

  13. Examination of the surface coating removed from K-East Basin fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Abrefah, J.; Marschman, S.C.; Jenson, E.D.

    1998-05-01

    This report provides the results of studies conducted on coatings discovered on the surfaces of some N-Reactor spent nuclear fuel (SNF) elements stored at the Hanford K-East Basin. These elements had been removed from the canisters and visually examined in-basin during FY 1996 as part of a series of characterization tests. The characterization tests are being performed to support the Integrated Process Strategy developed to package, dry, transport, and store the SNF in an interim storage facility on the Hanford site. Samples of coating materials were removed from K-East canister elements 2350E and 2540E, which had been sent, along with nine other elements, to the Postirradiation Testing Laboratory (327 Building) for further characterization following the in-basin examinations. These coating samples were evaluated by Pacific Northwest National Laboratory using various analytical methods. This report is part of the overall studies to determine the drying behavior of corrosion products associated with the K-Basin fuel elements. Altogether, five samples of coating materials were analyzed. These analyses suggest that hydration of the coating materials could be an additional source of moisture in the Multi-Canister Overpacks being used to contain the fuel for storage.

  14. A comparative effect of various surface chemical treatments on the resin composite-composite repair bond strength

    Directory of Open Access Journals (Sweden)

    Shaloo Gupta

    2015-01-01

    Full Text Available Aim: The aim of this in vitro study was an attempt to investigate the effect of different surface treatments on the bond strength between pre-existing composite and repair composite resin. Materials and Methods: Forty acrylic blocks were prepared in a cuboidal mould. In each block, a well of 5 mm diameter and 5 mm depth was prepared to retain the composite resin (Filtek™ Z350, 3M/ESPE. Aging of the composite discs was achieved by storing them in water at 37°C for 1 week, and after that were divided into 5 groups (n = 8 according to surface treatment: Group I- 37% phosphoric acid, Group II-10% hydrofluoric acid, Group III-30% citric acid, Group IV-7% maleic acid and Group V- Adhesive (no etchant. The etched surfaces were rinsed and dried followed by application of bonding agent (Adper™ Single Bond 2. 3M/ESPE. The repair composite was placed on aged composite, light-cured for 40 seconds and stored in water at 37°C for 1 week. Shear bond strength between the aged and the new composite resin was determined with a universal testing machine (crosshead speed of 0.5 mm/min. Statistical Analysis: The compressive shear strengths were compared for differences using ANOVA test followed by Tamhane′s T2 post hoc analysis. Results: The surface treatment with 10% hydrofluoric acid showed the maximum bond strength followed by 30% citric acid, 7% maleic acid and 37% phosphoric acid in decreasing order. Conclusion: The use of 10% hydrofluoric acid can be a good alternative for surface treatment in repair of composite resin restoration as compared to commonly used 37% orthophosphoric acid.

  15. Elemental Composition of 433 Eros: New Calibration of the NEAR-Shoemaker XRS Data

    Science.gov (United States)

    Lim, L. F.; Nittler, L. R.; Starr, R. D.; McClanahan, T. P.

    2005-01-01

    We present relative elemental abundances for six elements (Mg, Al, Si, S, Ca, Fe) in the surface layer of 433 Eros, derived from a new analysis of the solar induced fluorescence measured by the NEARShoemaker X ray Spectrometer (XRS).XRS derived elemental abundances have been presented before. However, calibration of XRS data depends critically on knowledge of the incident solar spectrum, which varies greatly on time scales of seconds to minutes. Unfortunately, the gas solar monitor carried by NEAR was inadequately calibrated prior to launch. The previously published XRS results were based partly on broadband measurements by the Earthorbiting GOES8 (Geostationary Operational Environmental Satellites) Xray detectors and partly on a preliminary solar monitor calibration carried out by the present authors. The new solar monitor calibration is based on a more recent set of physical models of the solar spectrum at various temperatures, an improved fitting procedure, analysis of a large number of flight spectra, and comparison with concurrent data from the GOES Xray detectors. In addition, the new analysis includes data from three solar flares not considered in earlier papers.

  16. 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.

  17. 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.

  18. Simplified welding distortion analysis for fillet welding using composite shell elements

    Directory of Open Access Journals (Sweden)

    Mingyu Kim

    2015-05-01

    Full Text Available This paper presents the simplified welding distortion analysis method to predict the welding deformation of both plate and stiffener in fillet welds. Currently, the methods based on equivalent thermal strain like Strain as Direct Boundary (SDB has been widely used due to effective prediction of welding deformation. Regarding the fillet welding, however, those methods cannot represent deformation of both members at once since the temperature degree of freedom is shared at the intersection nodes in both members. In this paper, we propose new approach to simulate deformation of both members. The method can simulate fillet weld deformations by employing composite shell element and using different thermal expansion coefficients according to thickness direction with fixed temperature at intersection nodes. For verification purpose, we compare of result from experiments, 3D thermo elastic plastic analysis, SDB method and proposed method. Compared of experiments results, the proposed method can effectively predict welding deformation for fillet welds.

  19. Crack path and fracture surface modifications in cement composites

    Directory of Open Access Journals (Sweden)

    Sajjad Ahmad

    2015-10-01

    Full Text Available There is a tremendous increase in the use of high strength and high performance self-consolidating cementitious composites due to their superior workability and mechanical strengths. Cement composites are quasi-brittle in nature and possess extremely low tensile strength as compared to their compressive strength. Due to the low tensile strength capacity, cracks develop in cementitious composites due to the drying shrinkage, plastic settlements and/or stress concentrations (due to external restrains and/or applied stresses etc. These cracks developed at the nanoscale may grow rapidly due to the applied stresses and join together to form micro and macro cracks. The growth of cracks from nanoscale to micro and macro scale is very rapid and may lead to sudden failure of the cement composites. The present paper reports the modifications in the crack growth pattern of the high performance cement composites to achieve enhanced ductility and toughness. The objective was accomplished by the incorporation of the micro sized inert particulates in the cement composite matrix. The results indicate that the incorporation of micro sized inert particles acted as the obstacles in the growth of the cracks thus improving the ductility and the energy absorption capacity of the self-consolidating cementitious composites.

  20. 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

  1. Changes of electrical conductivity of the metal surface layer by the laser alloying with foreign elements

    Science.gov (United States)

    Kostrubiec, Franciszek; Pawlak, Ryszard; Raczynski, Tomasz; Walczak, Maria

    1994-09-01

    Laser treatment of the surface of materials is of major importance for many fields technology. One of the latest and most significant methods of this treatment is laser alloying consisting of introducing foreign atoms into the metal surface layer during the reaction of laser radiation with the surface. This opens up vast possibilities for the modification of properties of such a layer (obtaining layers of increased microhardness, increased resistance to electroerosion in an electric arc, etc.). Conductivity of the material is a very important parameter in case of conductive materials used for electrical contacts. The paper presents the results of studies on change in electrical conductivity of the surface layer of metals alloyed with a laser. A comparative analysis of conductivity of base metal surface layers prior to and following laser treatment has been performed. Depending on the base metal and the alloying element, optical treatment parameters allowing a required change in the surface layer conductivity have been selected. A very important property of the contact material is its resistance to plastic strain. It affects the real value of contact surface coming into contact and, along with the material conductivity, determines contact resistance and the amount of heat generated in place of contact. These quantities are directly related to the initiation and the course of an arc discharge, hence they also affect resistance to electroerosion. The parameter that reflects plastic properties with loads concentrated on a small surface, as is the case with a reciprocal contact force of two real surfaces with their irregularities being in contact, is microhardness. In the paper, the results of investigations into microhardness of modified surface layers compared with base metal microhardness have been presented.

  2. Levels of particulate air pollution, its elemental composition, determinants and health effects in metro systems

    Science.gov (United States)

    Nieuwenhuijsen, M. J.; Gómez-Perales, J. E.; Colvile, R. N.

    The aim of this study was to review and summarise the levels of particulate air pollution, its elemental composition, its determinants, and its potential health effects in metro systems. A number of studies have been conducted to assess the levels of particulate matter and its chemical composition in metro systems. The monitoring equipment used varied and may have led to different reporting and makes it more difficult to compare results between metro systems. Some of the highest average levels of particulate matter were measured in the London metro system. Whereas some studies have reported higher levels of particulate matter in the metro system (e.g. London, Helsinki, Stockholm) compared to other modes of transport (London) and street canyons (Stockholm and Helsinki), other studies reported lower levels in the metro system (e.g. Hong Kong, Guangzhou, and Mexico City). The differences may be due to different material of the wheel, ventilation levels and breaking systems but there is no good evidence to what extent the differences may be explained by this, except perhaps for some elements (e.g. Fe, Mn). The dust in the metro system was shown to be more toxic than ambient airborne particulates, and its toxicity was compared with welding dust. The higher toxicity may be due to the higher iron content. Although the current levels of particulate matter and toxic matter are unlikely to lead to any significant excess health effects in commuters, they should be reduced where possible. It will be difficult to introduce measures to reduce the levels in older metro systems, e.g. by introducing air conditioning in London, but certainly they should be part of any new designs of metro systems.

  3. Enhanced corrosion resistance of A3xx.x/SiCp composites in chloride media by La surface treatments

    International Nuclear Information System (INIS)

    Pardo, A.; Merino, M.C.; Arrabal, R.; Feliu, S.; Viejo, F.; Carboneras, M.

    2006-01-01

    The influence of silicon carbide particles (SiCp) proportion and matrix composition of aluminium metal matrix composites (A3xx.x/SiCp) modified by lanthanum-based conversion or electrolysis coating was evaluated in 3.5 wt% NaCl aerated solution. The intermetallic compounds were preferentially covered by lanthanum-based conversion coatings obtained by immersion in 50 deg. C solution of La(III) salt, and the intermetallic compounds, SiCp and aluminium matrix were covered by lanthanum electrolysis treatment. The corrosion process was studied on the basis of gravimetric tests and electrochemical impedance spectroscopy (EIS) during immersion in 3.5 wt% NaCl aerated solution. The composition of both La coating and corrosion products was analyzed before and after accelerated testing, by scanning electron microscopy (SEM), atomic force microscopy (AFM), low-angle X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to determine the influence of surface microstructural changes on corrosion behaviour during exposure to the corrosive environment. The corrosion process was more influenced by the concentration of alloy elements in the matrix than by the proportion of SiCp reinforcement. Both lanthanum treated surfaces presented better behaviour to chloride solution corrosion than original composite surfaces without treatment; however, electrolysis afforded a higher degree of protection than the conversion treatment because the coating was more extensive

  4. A Finite Element Model of a MEMS-based Surface Acoustic Wave Hydrogen Sensor

    Directory of Open Access Journals (Sweden)

    Walied A. Moussa

    2010-02-01

    Full Text Available Hydrogen plays a significant role in various industrial applications, but careful handling and continuous monitoring are crucial since it is explosive when mixed with air. Surface Acoustic Wave (SAW sensors provide desirable characteristics for hydrogen detection due to their small size, low fabrication cost, ease of integration and high sensitivity. In this paper a finite element model of a Surface Acoustic Wave sensor is developed using ANSYS12© and tested for hydrogen detection. The sensor consists of a YZ-lithium niobate substrate with interdigital electrodes (IDT patterned on the surface. A thin palladium (Pd film is added on the surface of the sensor due to its high affinity for hydrogen. With increased hydrogen absorption the palladium hydride structure undergoes a phase change due to the formation of the β-phase, which deteriorates the crystal structure. Therefore with increasing hydrogen concentration the stiffness and the density are significantly reduced. The values of the modulus of elasticity and the density at different hydrogen concentrations in palladium are utilized in the finite element model to determine the corresponding SAW sensor response. Results indicate that with increasing the hydrogen concentration the wave velocity decreases and the attenuation of the wave is reduced.

  5. Shear-bond-strength of orthodontic brackets to aged nano-hybrid composite-resin surfaces using different surface preparation.

    Science.gov (United States)

    Demirtas, Hatice Kubra; Akin, Mehmet; Ileri, Zehra; Basciftci, Faruk Ayhan

    2015-01-01

    The aim of this study was to evaluate the effects of different surface preparation methods on the shear bond strength (SBS) of orthodontic metal brackets to aged nano-hybrid resin composite surfaces in vitro. A total of 100 restorative composite resin discs, 6 mm in diameter and 3 mm thick, were obtained and treated with an ageing procedure. After ageing, the samples were randomly divided as follows according to surface preparation methods: (1)Control, (2)37% phosphoric acid gel, (3)Sandblasting, (4)Diamond bur, (5)Air-flow and 20 central incisor teeth were used for the control etched group. SBS test were applied on bonded metal brackets to all samples. SBS values and residual adhesives were evaluated. Analysis of variance showed a significant difference (porthodontic metal brackets to nano-hybrid composite resin surfaces.

  6. Tetrathionate and Elemental Sulfur Shape the Isotope Composition of Sulfate in Acid Mine Drainage

    Directory of Open Access Journals (Sweden)

    Nurgul Balci

    2017-08-01

    Full Text Available Sulfur compounds in intermediate valence states, for example elemental sulfur, thiosulfate, and tetrathionate, are important players in the biogeochemical sulfur cycle. However, key understanding about the pathways of oxidation involving mixed-valance state sulfur species is still missing. Here we report the sulfur and oxygen isotope fractionation effects during the oxidation of tetrathionate (S4O62− and elemental sulfur (S° to sulfate in bacterial cultures in acidic conditions. Oxidation of tetrathionate by Acidithiobacillus thiooxidans produced thiosulfate, elemental sulfur and sulfate. Up to 34% of the tetrathionate consumed by the bacteria could not be accounted for in sulfate or other intermediate-valence state sulfur species over the experiments. The oxidation of tetrathionate yielded sulfate that was initially enriched in 34S (ε34SSO4−S4O6 by +7.9‰, followed by a decrease to +1.4‰ over the experiment duration, with an average ε34SSO4−S4O6 of +3.5 ± 0.2‰ after a month of incubation. We attribute this significant sulfur isotope fractionation to enzymatic disproportionation reactions occurring during tetrathionate decomposition, and to the incomplete transformation of tetrathionate into sulfate. The oxygen isotope composition of sulfate (δ18OSO4 from the tetrathionate oxidation experiments indicate that 62% of the oxygen in the formed sulfate was derived from water. The remaining 38% of the oxygen was either inherited from the supplied tetrathionate, or supplied from dissolved atmospheric oxygen (O2. During the oxidation of elemental sulfur, the product sulfate became depleted in 34S between −1.8 and 0‰ relative to the elemental sulfur with an average for ε34SSO4−S0 of −0.9 ± 0.2‰ and all the oxygen atoms in the sulfate derived from water with an average normal oxygen isotope fractionation (ε18OSO4−H2O of −4.4‰. The differences observed in δ18OSO4 and the sulfur isotope composition of sulfate (δ34SSO4

  7. 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.

  8. Elemental composition of PM 10 and PM 2.5 in urban environment in South Brazil

    Science.gov (United States)

    Braga, C. F.; Teixeira, E. C.; Meira, L.; Wiegand, F.; Yoneama, M. L.; Dias, J. F.

    The purpose of the present study is to analyze the elemental composition and the concentrations of PM 10 and PM 2.5 in the Guaíba Hydrographic Basin with HV PM 10 and dichotomous samplers. Three sampling sites were selected: 8° Distrito, CEASA and Charqueadas. The sampling was conducted from October 2001 to December 2002. The mass concentrations of the samplers were evaluated, while the elemental concentrations of Si, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu and Zn were determined using the Particle-Induced X-ray Emission (PIXE) technique. Factor Analysis and Canonical Correlation Analysis were applied to the chemical and meteorological variables in order to identify the sources of particulate matter. Industrial activities such as steel plants, coal-fired power plants, hospital waste burning, vehicular emissions and soil were identified as the sources of the particulate matter. Concentration levels higher than the daily and the annual average air quality standards (150 and 50 μg m -3, respectively) set by the Brazilian legislation were not observed.

  9. Structural Phenomenon of Cement-Based Composite Elements in Ultimate Limit State

    Directory of Open Access Journals (Sweden)

    I. Iskhakov

    2016-01-01

    Full Text Available Cement-based composite materials have minimum of two components, one of which has higher strength compared to the other. Such materials include concrete, reinforced concrete (RC, and ferrocement, applied in single- or two-layer RC elements. This paper discusses experimental and theoretical results, obtained by the authors in the recent three decades. The authors have payed attention to a structural phenomenon that many design features (parameters, properties, etc. at ultimate limit state (ULS of a structure are twice higher (or lower than at initial loading state. This phenomenon is evident at material properties, structures (or their elements, and static and/or dynamic structural response. The phenomenon is based on two ideas that were developed by first author: quasi-isotropic state of a structure at ULS and minimax principle. This phenomenon is supported by experimental and theoretical results, obtained for various structures, like beams, frames, spatial structures, and structural joints under static or/and dynamic loadings. This study provides valuable indicators for experiments’ planning and estimation of structural state. The phenomenon provides additional equation(s for calculating parameters that are usually obtained experimentally and can lead to developing design concepts and RC theory, in which the number of empirical design coefficients will be minimal.

  10. Revisiting the elemental composition and the calorific value of the organic fraction of municipal solid wastes.

    Science.gov (United States)

    Komilis, Dimitrios; Evangelou, Alexandros; Giannakis, Georgios; Lymperis, Constantinos

    2012-03-01

    In this work, the elemental content (C, N, H, S, O), the organic matter content and the calorific value of various organic components that are commonly found in the municipal solid waste stream were measured. The objective of this work was to develop an empirical equation to describe the calorific value of the organic fraction of municipal solid waste as a function of its elemental composition. The MSW components were grouped into paper wastes, food wastes, yard wastes and plastics. Sample sizes ranged from 0.2 to 0.5 kg. In addition to the above individual components, commingled municipal solid wastes were sampled from a bio-drying facility located in Crete (sample sizes ranged from 8 to 15 kg) and were analyzed for the same parameters. Based on the results of this work, an improved empirical model was developed that revealed that carbon, hydrogen and oxygen were the only statistically significant predictors of calorific value. Total organic carbon was statistically similar to total carbon for most materials in this work. The carbon to organic matter ratio of 26 municipal solid waste substrates and of 18 organic composts varied from 0.40 to 0.99. An approximate chemical empirical formula calculated for the organic fraction of commingled municipal solid wastes was C(32)NH(55)O(16). Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Humidity Sensing Properties of Surface Modified Polyaniline Metal Oxide Composites

    Directory of Open Access Journals (Sweden)

    S. C. Nagaraju

    2014-01-01

    Full Text Available Polyaniline- (PANI praseodymium Oxide (Pr2O3 composites have been synthesized by in situ polymerization method with different weight percentages. The synthesized composites have been characterized by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The temperature dependent conductivity shows that the conductivity is due to the hopping of polarons and bipolarons. These composites show negative thermal coefficient (α behavior as a function of temperature, which is characteristic behavior of semiconducting materials. Sensor studies have been carried out by two-probe method and found that the sensitivity increases with increase in % RH. It is noticed that stability increase is due to the presence of Pr2O3 in polyaniline up to 30 wt%. A fast recovery and response time along with high sensitivity make these composites suitable for humidity sensors.

  12. Сomposition and ratio of the chemical elements on the surfaces different by height of reindeer lichen podetia Cladonia rangiferina

    Directory of Open Access Journals (Sweden)

    Byazrov Lev

    2016-06-01

    Full Text Available In the paper the composition of 21 elements – Mg, Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Ba, Pb – was compared in the upper, central, and lower parts of podetia surfaces of the reindeer lichen Cladonia rangiferina, sampled on the slope of Barguzinsky chain. For the measurement of the elements content (%, a sample-nondestructive μ-XRF spectrometer was used. It was stated that the share (% of the most elements, except for Cu and Zn, was highly variable. The content of the elements on the surfaces differs significantly between the studied parts of C. rangiferina podetia: mean values of the content of P, S, Cl, and K were statistically higher on the surface of the upper part of podetia, while those of Al, Si, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Co, and the total content – on the surface of the lower part of podetia. On all the parts of podetia very high value of the enrichment factor for As and Pb was established, and It was increased for P, Co, Ni, Cu, Zn.

  13. A parametric finite element method for solid-state dewetting problems with anisotropic surface energies

    Science.gov (United States)

    Bao, Weizhu; Jiang, Wei; Wang, Yan; Zhao, Quan

    2017-02-01

    We propose an efficient and accurate parametric finite element method (PFEM) for solving sharp-interface continuum models for solid-state dewetting of thin films with anisotropic surface energies. The governing equations of the sharp-interface models belong to a new type of high-order (4th- or 6th-order) geometric evolution partial differential equations about open curve/surface interface tracking problems which include anisotropic surface diffusion flow and contact line migration. Compared to the traditional methods (e.g., marker-particle methods), the proposed PFEM not only has very good accuracy, but also poses very mild restrictions on the numerical stability, and thus it has significant advantages for solving this type of open curve evolution problems with applications in the simulation of solid-state dewetting. Extensive numerical results are reported to demonstrate the accuracy and high efficiency of the proposed PFEM.

  14. Stress analysis of composite wind turbine blade by finite element method

    Science.gov (United States)

    Yeh, Meng-Kao; Wang, Chen-Hsu

    2017-10-01

    In this study, the finite element analysis software ANSYS was used to analyze the composite wind turbine blade. The wind turbine blade model used is adopted from the 5 MW model of US National Renewable Energy Laboratory (NREL). The wind turbine blade is a sandwich structure, comprising outermost carbon fiber cloth/epoxy composites, the inner glass fiber/vinylester layers, and PVC foam core, together with stiffeners. The wind pressure is converted into the load on the blade structure. The stress distribution and deformation of wind turbine blade were obtained by considering different pitch angles and at different angular positions. The Tsai-Hill criterion was used to determine the failure of wind turbine blade. The results show that at the 0° pitch angle, the wind turbine blade is subjected to the largest combined load and therefore the stress is the largest; with the increasing pitch angle, the load gradually decreases and the stress is also smaller. The stress and displacement are the greatest when the wind blade is located at 120° angular position from its highest vertex.

  15. Major, minor and trace element composition of cloudwater and rainwater at Plynlimon

    Directory of Open Access Journals (Sweden)

    J. Wilkinson

    1997-01-01

    Full Text Available The composition of cloudwater samples collected at Plynlimon, Mid Wales by the Institute of Hydrology is described based on one of the most comprehensive chemical records for deposition in the UK. Comparison with bulk rainwater samples for the same area demonstrates a tenfold enrichment of most elements in cloudwater. Large variations in cloudwater composition occur due to variations in marine and terrestrial/anthropogenic sources, general weather patterns, atmospheric circulation and seasonal effects. All trace metal concentrations are associated with anthropogenic contamination. The lanthanides La, Cc and Pr, and Y are highly correlated in ratios associated with lithogenic sources and fossil fuel combustion. Outliers suggest the influence of catalysts used in the petrochemical cracking process. Plantation forestry significantly enhances the annual deposition of solutes from cloudwater; between 15 and 40% of most constituents to upland forested catchments and around 50% for NO3, B and Cd come from cloud deposition. In upland moorland areas, only 10% of the annual deposited load of inorganic constituents comes from cloudwater.

  16. 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.

  17. [Effect of thermal cycling on surface microstructure of different light-curing composite resins].

    Science.gov (United States)

    Lv, Da; Liu, Kai-Lei; Yao, Yao; Zhang, Wei-Sheng; Liao, Chu-Hong; Jiang, Hong

    2015-04-01

    To evaluate the effect of thermal cycling on surface microstructure of different light-curing composite resins. A nanofilled composite (Z350) and 4 microhybrid composites (P60, Z250, Spectrum, and AP-X) were fabricated from lateral to center to form cubic specimens. The lateral surfaces were abrased and polished before water storage and 40 000 thermal cycles (5/55 degrees celsius;). The mean surface roughness (Ra) were measured and compared before and after thermal cycling, and the changes of microstructure were observed under scanning electron microscope (SEM). Significant decreases of Ra were observed in the composites, especially in Spectrum (from 0.164±0.024 µm to 0.140±0.017 µm, Presins, and fissures occurred on Z350 following the thermal cycling. Water storage and thermal cycling may produce polishing effect on composite resins and cause fissures on nanofilled composite resins.

  18. Surface roughness comparison of methacrylate and silorane-based composite resins after 40% hydrogen peroxide application

    Directory of Open Access Journals (Sweden)

    Rori Sasmita

    2018-01-01

    Full Text Available The change of the tooth colour could be restored with bleaching. The tooth bleaching will affects the surface roughness of the composite resins. Recently, the material basis for composite resins has developed, among others are methacrylate-based and silorane based composite resins. The objective of this study was to distinguish the surface roughness value of methacrylate-based composite resin and silorane based composite resins. This research was quasi-experimental. The sample used in this study were methacrylate and silorane based composite resins in discs form, with the size of 6 mm and the thickness of 3 mm, manufactured into 20 specimens and divided into 2 groups. The control group was immersed in the artificial saliva, and the treatment group was applied with 40% hydrogen peroxide. The result of the experiment analyzed using unpaired sample t-test showed significant differences in the average value of the surface roughness after the application of 40% hydrogen peroxide. The average value of methacrylate and silorane based composite resins were 2.744 μm and 3.417 μm, respectively. There was a difference in the surface roughness of methacrylate and silorane based composite resin compounds after the application of 40% hydrogen peroxide. The surface roughness value of the silorane-based composite resin was higher than the methacrylate-based.

  19. Finite element modeling to determine thermal residual strain distribution of bonded composite repairs for structural health monitoring design

    Science.gov (United States)

    Baker, Wayne; Jones, Rhys; Davis, Claire; Galea, Stephen C.

    2002-11-01

    The economic implication of fleet upgrades, particularly in Australia with military aircraft such as the F-111 and F/A-18, has led to an increasing reliance on composite repair technology to address fatigue and corrosion-affected aircraft components. The increasing use of such repairs has led to a research effort to develop various in-situ health monitoring systems that may be incorporated with a repair. This paper reports on the development of a theoretical methodology that uses finite element analysis (FEA) to model the strain profiles which optical sensors, on or within the patch, will be exposed to under various operational scenarios, including load and disbond. Numerical techniques are then used to predict the fibre Bragg grating (FBG) reflections which occur with these strain profiles. The quality of these reflection are a key consideration when designing FBG based structural health monitoring (SHM) systems. This information can be used to optimise the location of both surface mounted, and embedded sensors, and determine feasibility of SHM system design. Research was conducted into the thermal residual strain (TRS) within the patch. A finite element study revealed the presence of significant thermal residual strain gradients along the surface of the tapered region of the patch. As Bragg gratings are particularly sensitive to strain gradients, (producing a result similar to a chirped grating) the strain gradient on the composite at potential sensor locations both under load, and in the event of disbond was considered. A sufficiently high gradient leads to an altered Bragg reflection. These spurious reflections need to be considered, and theoretically obtained reflections can provide information to allow for load scenarios where the Bragg shift is not a smooth, well defined peak. It can also be shown that embedded fibres offer a higher average thermal residual strain reading, while being subject to a much lower strain gradient. This particularly favors the

  20. Impact of snow deposition on major and trace element concentrations and elementary fluxes in surface waters of the Western Siberian Lowland across a 1700 km latitudinal gradient

    Science.gov (United States)

    Shevchenko, Vladimir P.; Pokrovsky, Oleg S.; Vorobyev, Sergey N.; Krickov, Ivan V.; Manasypov, Rinat M.; Politova, Nadezhda V.; Kopysov, Sergey G.; Dara, Olga M.; Auda, Yves; Shirokova, Liudmila S.; Kolesnichenko, Larisa G.; Zemtsov, Valery A.; Kirpotin, Sergey N.

    2017-11-01

    In order to better understand the chemical composition of snow and its impact on surface water hydrochemistry in the poorly studied Western Siberia Lowland (WSL), the surface layer of snow was sampled in February 2014 across a 1700 km latitudinal gradient (ca. 56.5 to 68° N). We aimed at assessing the latitudinal effect on both dissolved and particulate forms of elements in snow and quantifying the impact of atmospheric input to element storage and export fluxes in inland waters of the WSL. The concentration of dissolved+colloidal (metalloids (As, Sb), Mo and U in the discontinuous to continuous permafrost zone (64-68° N) can be explained solely by melting of accumulated snow. The impact of snow deposition on riverine fluxes of elements strongly increased northward, in discontinuous and continuous permafrost zones of frozen peat bogs. This was consistent with the decrease in the impact of rock lithology on river chemical composition in the permafrost zone of the WSL, relative to the permafrost-free regions. Therefore, the present study demonstrates significant and previously underestimated atmospheric input of many major and trace elements to their riverine fluxes during spring floods. A broader impact of this result is that current estimations of river water fluxes response to climate warming in high latitudes may be unwarranted without detailed analysis of winter precipitation.

  1. The transient response for different types of erodable surface thermocouples using finite element analysis

    Directory of Open Access Journals (Sweden)

    Mohammed Hussein

    2007-01-01

    Full Text Available The transient response of erodable surface thermocouples has been numerically assessed by using a two dimensional finite element analysis. Four types of base metal erodable surface thermocouples have been examined in this study, included type-K (alumel-chromel, type-E (chromel-constantan, type-T (copper-constantan, and type-J (iron-constantan with 50 mm thick- ness for each. The practical importance of these types of thermocouples is to be used in internal combustion engine studies and aerodynamics experiments. The step heat flux was applied at the surface of the thermocouple model. The heat flux from the measurements of the surface temperature can be commonly identified by assuming that the heat transfer within these devices is one-dimensional. The surface temperature histories at different positions along the thermocouple are presented. The normalized surface temperature histories at the center of the thermocouple for different types at different response time are also depicted. The thermocouple response to different heat flux variations were considered by using a square heat flux with 2 ms width, a sinusoidal surface heat flux variation width 10 ms period and repeated heat flux variation with 2 ms width. The present results demonstrate that the two dimensional transient heat conduction effects have a significant influence on the surface temperature history measurements made with these devices. It was observed that the surface temperature history and the transient response for thermocouple type-E are higher than that for other types due to the thermal properties of this thermocouple. It was concluded that the thermal properties of the surrounding material do have an impact, but the properties of the thermocouple and the insulation materials also make an important contribution to the net response.

  2. Finite element simulation of photoacoustic fiber optic sensors for surface corrosion detection on a steel rod

    Science.gov (United States)

    Tang, Qixiang; Owusu Twumasi, Jones; Hu, Jie; Wang, Xingwei; Yu, Tzuyang

    2018-03-01

    Structural steel members have become integral components in the construction of civil engineering infrastructures such as bridges, stadiums, and shopping centers due to versatility of steel. Owing to the uniqueness in the design and construction of steel structures, rigorous non-destructive evaluation techniques are needed during construction and operation processes to prevent the loss of human lives and properties. This research aims at investigating the application of photoacoustic fiber optic transducers (FOT) for detecting surface rust of a steel rod. Surface ultrasonic waves propagation in intact and corroded steel rods was simulated using finite element method (FEM). Radial displacements were collected and short-time Fourier transform (STFT) was applied to obtain the spectrogram. It was found that the presence of surface rust between the FOT and the receiver can be detected in both time and frequency domain. In addition, spectrogram can be used to locate and quantify surface rust. Furthermore, a surface rust detection algorithm utilizing the FOT has been proposed for detection, location and quantification of the surface rust.

  3. The comparison of element composition of Venus, Earth, Mars, and chondrites in the light of the Mendeleev Periodic Law

    International Nuclear Information System (INIS)

    Chuburkov, Yu.T.

    1998-01-01

    The share of free neutral atoms, N 0 , for all elements in Protoplanet nebula has been determined with the account of their abundance and physico-chemical properties. The linear dependence for the ratio of nonvolatile and volatile elements in chondrites and igneous rocks of the Earth on N 0 was obtained. The Mendeleev Periodic Law was used to obtain the proof of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. To this end the concentration ratios of element-analogous with different N 0 in the matters of Venus, Earth, Mars, and chondrites were compared. The data obtained are sufficient demonstration of the existence of the hypothetical process of element magnetic separation in Protoplanet nebula. With the account of the above said, it was shown that Shergotty and Tunguska meteorites by their relative elemental composition are close to Mars and asteroids, respectively. (author)

  4. Measurement and modification of first-wall surface composition in the Oak Ridge Tokamak (ORMAK)

    International Nuclear Information System (INIS)

    Clausing, R.E.; Emerson, L.C.; Heatherly, L.; Colchin, R.J.; Twichell, J.C.

    1975-01-01

    Impurities coming into the plasma from the walls of present-day toroidal plasma confinement devices modify plasma behavior substantially. Small fractions of high-Z ions in the plasma greatly decrease plasma temperatures and increase plasma energy losses. Impurities from the ''first-wall'' in ORMAK were studied. Auger electron spectroscopy, soft x-ray appearance potential spectroscopy, and other surface sensitive techniques were used to characterize the surface composition of the first wall and to develop methods to remove carbon and oxygen. Oxygen glow discharge cleaning has been shown, in the laboratory, to be an effective way of removing carbon from gold films (simulated ORMAK linear material) and the use of oxygen discharge cleaning in ORMAK has resulted in a decrease in plasma contamination, a 50 percent increase in plasma current and an accompanying increase in plasma temperature. In spite of these improvements the walls of ORMAK are far from clean. Substantial amounts of carbon, oxygen, iron and other elements remain. (auth)

  5. Hybrid of Natural Element Method (NEM with Genetic Algorithm (GA to find critical slip surface

    Directory of Open Access Journals (Sweden)

    Shahriar Shahrokhabadi

    2014-06-01

    Full Text Available One of the most important issues in geotechnical engineering is the slope stability analysis for determination of the factor of safety and the probable slip surface. Finite Element Method (FEM is well suited for numerical study of advanced geotechnical problems. However, mesh requirements of FEM creates some difficulties for solution processing in certain problems. Recently, motivated by these limitations, several new Meshfree methods such as Natural Element Method (NEM have been used to analyze engineering problems. This paper presents advantages of using NEM in 2D slope stability analysis and Genetic Algorithm (GA optimization to determine the probable slip surface and the related factor of safety. The stress field is produced under plane strain condition using natural element formulation to simulate material behavior analysis utilized in conjunction with a conventional limit equilibrium method. In order to justify the preciseness and convergence of the proposed method, two kinds of examples, homogenous and non-homogenous, are conducted and results are compared with FEM and conventional limit equilibrium methods. The results show the robustness of the NEM in slope stability analysis.

  6. 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

  7. Thermal performance enhancement of erythritol/carbon foam composites via surface modification of carbon foam

    Science.gov (United States)

    Li, Junfeng; Lu, Wu; Luo, Zhengping; Zeng, Yibing

    2017-03-01

    The thermal performance of the erythritol/carbon foam composites, including thermal diffusivity, thermal capacity, thermal conductivity and latent heat, were investigated via surface modification of carbon foam using hydrogen peroxide as oxider. It was found that the surface modification enhanced the wetting ability of carbon foam surface to the liquid erythritol of the carbon foam surface and promoted the increase of erythritol content in the erythritol/carbon foam composites. The dense interfaces were formed between erythritol and carbon foam, which is due to that the formation of oxygen functional groups C=O and C-OH on the carbon surface increased the surface polarity and reduced the interface resistance of carbon foam surface to the liquid erythritol. The latent heat of the erythritol/carbon foam composites increased from 202.0 to 217.2 J/g through surface modification of carbon foam. The thermal conductivity of the erythritol/carbon foam composite before and after surface modification further increased from 40.35 to 51.05 W/(m·K). The supercooling degree of erythritol also had a large decrease from 97 to 54 °C. Additionally, the simple and effective surface modification method of carbon foam provided an extendable way to enhance the thermal performances of the composites composed of carbon foams and PCMs.

  8. Neutron activation analysis for environmental trace element research determination of elemental composition of sediments in the Sea of Galillee, Israel

    Energy Technology Data Exchange (ETDEWEB)

    Lavi, N; Ne` eman, E; Brenner, S; Butenko, V [Tel Aviv Univ. (Israel). Medical School

    1996-12-01

    The aims of this work were to: a) demonstrate the effectiveness of instrumental neutron activation analysis for determining the background concentrations of trace elements in the sediments collected from the Sea of Gallile. b) determine the advantage factors for epithermal neutron irradiation. c) determine the contribution of silicon to the total {sup 28}Al activity by the {sup 28}Si(n,p){sup 28}Al reaction. c) check the validity of the method by determining the elemental content of U.S. NBS Standard Reference Material SRM-1633a (fly ash). d) calculate the average enrichment factors for the elements in sediments . e) determine the concentrations of the artificial radionuclides {sup 134}Cs, {sup 137}Cs and the naturally occurring radionuclides {sup 40}K, {sup 226}Ra and {sup 232}Th (authors).

  9. Radioactive elements on Mercury's surface from MESSENGER: implications for the planet's formation and evolution.

    Science.gov (United States)

    Peplowski, Patrick N; Evans, Larry G; Hauck, Steven A; McCoy, Timothy J; Boynton, William V; Gillis-Davis, Jeffery J; Ebel, Denton S; Goldsten, John O; Hamara, David K; Lawrence, David J; McNutt, Ralph L; Nittler, Larry R; Solomon, Sean C; Rhodes, Edgar A; Sprague, Ann L; Starr, Richard D; Stockstill-Cahill, Karen R

    2011-09-30

    The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances of the radioactive elements potassium (K, 1150 ± 220 parts per million), thorium (Th, 220 ± 60 parts per billion), and uranium (U, 90 ± 20 parts per billion) in Mercury's northern hemisphere. The abundance of the moderately volatile element K, relative to Th and U, is inconsistent with physical models for the formation of Mercury requiring extreme heating of the planet or its precursor materials, and supports formation from volatile-containing material comparable to chondritic meteorites. Abundances of K, Th, and U indicate that internal heat production has declined substantially since Mercury's formation, consistent with widespread volcanism shortly after the end of late heavy bombardment 3.8 billion years ago and limited, isolated volcanic activity since.

  10. Obsidians from the Kerkennah Islands (eastern Tunisia) and the PIXE elemental compositions of the Mediterranean peralkaline obsidians

    International Nuclear Information System (INIS)

    Le Bourdonnec, François-Xavier; Poupeau, Gérard; Boussofara, Ridha

    2015-01-01

    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

  11. 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.

  12. Mineral association composition and trace elements in urinary calculi in Ostrava region patients from 1978 to 2010

    Czech Academy of Sciences Publication Activity Database

    Martinec, Petr; Plasgura, P.; Machat, J.; Staněk, F.

    2011-01-01

    Roč. 10, č. 7 (2011), s. 462-462 ISSN 1569-9056. [EULIS 2011. London, 07.09.2011-10.09.2011] R&D Projects: GA ČR(CZ) GA203/09/1394 Institutional research plan: CEZ:AV0Z30860518 Keywords : urinary calculi * mineral association * chemical composition and trace elements Subject RIV: DD - Geochemistry Impact factor: 1.827, year: 2011 http://www.europeanurology.com/article/S1569-9056%2811%2961151-2/pdf/E03+Mineral+association,+composition+and+trace+elements+in+urinary+calculi+in+Ostrava+region+patients+from+1978+to+2010

  13. 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.

  14. Maxwell's equations in axisymmetrical geometry: coupling H(curl) finite element in volume and H(div) finite element in surface. The numerical code FuMel

    International Nuclear Information System (INIS)

    Cambon, S.; Lacoste, P.

    2011-01-01

    We propose a finite element method to solve the axisymmetric scattering problem posed on a regular bounded domain. Here we shall show how to reduce the initial 3D problem into a truncated sum of 2D independent problems posed into a meridian plane of the object. Each of these problem results in the coupling of a partial differential equation into the interior domain and an integral equation on the surface simulating the free space. Then variational volume and boundary integral formulations of Maxwell's equation on regular surfaces are derived. We introduce some general finite element adapted to cylindrical coordinates and constructed from nodal and mixed finite element both for the interior (volume) and for the integral equation (surface). (authors)

  15. Failure phenomena in fibre-reinforced composites. Part 6: a finite element study of stress concentrations in unidirectional carbon fibre-reinforced epoxy composites

    NARCIS (Netherlands)

    van den Heuvel, P.W.J.; Goutianos, S.; Young, R.J.; Peijs, A.A.J.M.

    2004-01-01

    A three-dimensional (3-D) finite element (FE) analysis of the stress situation around a fibre break in a unidirectional carbon fibre-reinforced epoxy composite has been performed. Two cases were considered: (i) good fibre/matrix adhesion and (ii) fibre/matrix debonding. In the case of good adhesion,

  16. Effects of 35% Carbamide Peroxide Gel on Surface Roughness and Hardness of Composite Resins

    Directory of Open Access Journals (Sweden)

    F. Sharafeddin

    2010-03-01

    Full Text Available Objective: Bleaching agents may not be safe for dental materials. The purpose of this invitro study was to evaluate the effects of Opalescent Quick "in-office bleaching gel" containing 35% carbamide peroxide on the surface roughness and hardness of microfilled(Heliomolar and hybride (Spectrum TPH composite resins.Materials and Methods: Twenty specimens of Spectrum TPH composite resins and twenty Heliomolar composite resins were fabricated using a metallic ring (6.5 mm diameter and 2.5 mm thickness and light cured, then their surfaces were polished. Specimens of each composite resin were divided into two equal groups. Ten specimens of each type of composite were stored in water at 37°C as the control groups and 35% carbamide peroxide gel (Opalescence Quick as the other group for 30 minutes a week for 3 weeks. Then the specimens were subject to roughness and hardness tests.Results: This study revealed that using 35% carbamide peroxide bleaching gels had no significant effect on the surface roughness of Spectrum TPH "hybrid" and Heliomolar "microfilled" composite resins. The surface hardness of Spectrum TPH composite treated with the subject gel significantly increased compared to heliomolar, which had no significant change after treatment with this bleaching gel.Conclusion: If tooth color matching of the composite had been satisfactory after office bleaching with 35% carbamide peroxide gel, this material would have been acceptable because it has no adverse effect on Heliomolar and Spectrum TPH composite resins.

  17. Three-dimensional modeling of chloroprene rubber surface topography upon composition

    Energy Technology Data Exchange (ETDEWEB)

    Žukienė, Kristina, E-mail: kristina.zukiene@ktu.lt [Department of Clothing and Polymer Products Technology, Kaunas University of Technology, Studentu St. 56, LT-51424 Kaunas (Lithuania); Jankauskaitė, Virginija [Department of Clothing and Polymer Products Technology, Kaunas University of Technology, Studentu St. 56, LT-51424 Kaunas (Lithuania); Petraitienė, Stase [Department of Applied Mathematics, Kaunas University of Technology, Studentu 50, LT-51368 Kaunas (Lithuania)

    2014-02-15

    In this study the effect of polymer blend composition on the surface roughness has been investigated and simulated. Three-dimensional modeling of chloroprene rubber film surface upon piperylene-styrene copolymer content was conducted. The efficiency of various surface roughness modeling methods, including Monte Carlo, surface growth and proposed method, named as parabolas, were compared. The required parameters for modeling were obtained from atomic force microscopy topographical images of polymer films surface. It was shown that experimental and modeled surfaces have the same correlation function. The quantitative comparison of function parameters was made. It was determined that novel parabolas method is suitable for three-dimensional polymer blends surface roughness description.

  18. Modified titanium surface with gelatin nano gold composite increases osteoblast cell biocompatibility

    International Nuclear Information System (INIS)

    Lee, Young-Hee; Bhattarai, Govinda; Aryal, Santosh; Lee, Nan-Hee; Lee, Min-Ho; Kim, Tae-Gun; Jhee, Eun-Chung; Kim, Hak-Yong; Yi, Ho-Keun

    2010-01-01

    This study examined the gelatin nano gold (GnG) composite for surface modification of titanium in addition to insure biocompatibility on dental implants or biomaterials. The GnG composite was constructed by gelatin and hydrogen tetrachloroaurate in presence of reducing agent, sodium borohydrate (NabH 4 ). The GnG composite was confirmed by UV-VIS spectroscopy and transmission electron microscopy (TEM). A dipping method was used to modify the titanium surface by GnG composite. Surface was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). The MC-3T3 E1 cell viability was assessed by trypan blue and the expression of proteins to biocompatibility were analyzed by Western blotting. The GnG composite showed well dispersed character, the strong absorption at 530 nm, roughness, regular crystal and clear C, Na, Cl, P, and Au signals onto titanium. Further, this composite allowed MC-3T3 E1 growth and viability compared to gelatin and pure titanium. It induced ERK activation and the expression of cell adherent molecules, FAK and SPARC, and growth factor, VEGF. However, GnG decreased the level of SAPK/JNK. This shows that GnG composite coated titanium surfaces have a good biocompatibility for osteoblast growth and attachment than in intact by simple and versatile dipping method. Furthermore, it offers good communication between cell and implant surfaces by regulating cell signaling and adherent molecules, which are useful to enhance the biocompatibility of titanium surfaces.

  19. Effect of the surface roughness on interfacial properties of carbon fibers reinforced epoxy resin composites

    International Nuclear Information System (INIS)

    Song Wei; Gu Aijuan; Liang Guozheng; Yuan Li

    2011-01-01

    The effect of the surface roughness on interfacial properties of carbon fibers (CFs) reinforced epoxy (EP) resin composite is studied. Aqueous ammonia was applied to modify the surfaces of CFs. The morphologies and chemical compositions of original CFs and treated CFs (a-CFs) were characterized by Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS). Compared with the smooth surface of original CF, the surface of a-CF has bigger roughness; moreover, the roughness increases with the increase of the treating time. On the other hand, no obvious change in chemical composition takes place, indicating that the treating mechanism of CFs by aqueous ammonia is to physically change the morphologies rather than chemical compositions. In order to investigate the effect of surface roughness on the interfacial properties of CF/EP composites, the wettability and Interfacial Shear Strength (IFSS) were measured. Results show that with the increase of the roughness, the wettabilities of CFs against both water and ethylene glycol improves; in addition, the IFSS value of composites also increases. These attractive phenomena prove that the surface roughness of CFs can effectively overcome the poor interfacial adhesions between CFs and organic matrix, and thus make it possible to fabricate advanced composites based on CFs.

  20. Semiquantitative and quantitative measurements for EDXRF in elemental chemical composition of pigments

    International Nuclear Information System (INIS)

    Costa, Elizabeth Cristina Soares da

    2005-02-01

    X-Ray fluorescence technique is largely used in the characterization of art and archaeological objects for restoration and conservation, allowing a multi-elemental, simultaneous and non destructive analysis. In this work it was used a portable XRF equipment of XRF that consists of a 238 Pu source ( 13,6 and 17,2 keV; 95 mCi) and a SI-PIN detector coupled to a 8 k multichannel analyser. The results were collected by a palmtop computer and later analysed in a PC, through the program AXIL-QXAS. The acquisition time for each measurement was 500 s. The measurements were accomplished in a wood sculpture (Santa Luzia image, number 164) from the collection of the Museu de Etnologia da Universidade de Sao Paulo (MAE-USP), in the following regions: (STL1) inferior side of the wood base exposed without finishing, (STL2) frontal inferior base of the pedestal (dark blue) (STL3), inferior part of the frontal dress (gold), (STL4) medium part of the dress (clear blue) (STL5) mantle (red), (STL6) back central lock of the hair in the backs (black), (STL7) right cheek (flesh-coloured) and (STL8) mantle (gold). The elements found in the STL1 region were: Al, Ca, Fe and a high concentration of Zn. In the region STL2 were found Al, C, Fe, Zn and the key element Cu. In the region STL3 - Ca, Zn and the key element Au. In the region STL4 it was found Zn and the key element Cu. In the region STL5 the key element S and Hg. In the region STL6 were found Fe, Ca, S and Hg. In the region STL 7 were found Al, Cu, Hg and Zn. In the region STL8 were found Ca, Al and Au, with high concentration. It was concluded that the possible pigments would be: STL2 and STL4 - CuCO 3 . Cu(OH) 2 + ZnO; STL3 and STL8 - Au; STL5 - HgS, STL6 - HgS mixed with other oxides, possibly of Fe and Mn, and STL 7 - HgS + ZnO. Standard samples of wood painted with pigments of the colors white, blue, red, rose, flesh color and green were also made. Through the XRF method it was verified that the white pigment is TiO 2 , the

  1. Testing external surface of fuel element tubes for power nuclear reactors

    International Nuclear Information System (INIS)

    Naugol'nykh, O.G.; Nelyubin, Yu.V.

    1987-01-01

    Optical methods are regarded perspective for discovery and detection of flaws of external surfaces of fuel element tubes. The TV method has highest information content among them. Two mock-ups of facilities based on the TV method using a ''dissector'' type TV device and a TV tube with charge accumulation (vidikon) have been developed. It is concluded that complex testing - combination of ultrasonic, photoelectric and TV methods in a facility is necessary for discovery and analysis of the whole variety of flaws, though sensitivity of the TV method is enough for disclosure of all the main defects

  2. Digital detection system of surface defects for large aperture optical elements

    International Nuclear Information System (INIS)

    Fan Yong; Chen Niannian; Gao Lingling; Jia Yuan; Wang Junbo; Cheng Xiaofeng

    2009-01-01

    Based on the light defect images against the dark background in a scattering imaging system, a digital detection system of surface defects for large aperture optical elements has been presented. In the system, the image is segmented by a multi-area self-adaptive threshold segmentation method, then a pixel labeling method based on replacing arrays is adopted to extract defect features quickly, and at last the defects are classified through back-propagation neural networks. Experiment results show that the system can achieve real-time detection and classification. (authors)

  3. Spatial Distribution and Fuzzy Health Risk Assessment of Trace Elements in Surface Water from Honghu Lake.

    Science.gov (United States)

    Li, Fei; Qiu, Zhenzhen; Zhang, Jingdong; Liu, Chaoyang; Cai, Ying; Xiao, Minsi

    2017-09-04

    Previous studies revealed that Honghu Lake was polluted by trace elements due to anthropogenic activities. This study investigated the spatial distribution of trace elements in Honghu Lake, and identified the major pollutants and control areas based on the fuzzy health risk assessment at screening level. The mean total content of trace elements in surface water decreased in the order of Zn (18.04 μg/L) > Pb (3.42 μg/L) > Cu (3.09 μg/L) > Cr (1.63 μg/L) > As (0.99 μg/L) > Cd (0.14 μg/L), within limits of Drinking Water Guidelines. The results of fuzzy health risk assessment indicated that there was no obvious non-carcinogenic risk to human health, while carcinogenic risk was observed in descending order of As > Cr > Cd > Pb. As was regarded to have the highest carcinogenic risk among selected trace elements because it generally accounted for 64% of integrated carcinogenic risk. Potential carcinogenic risk of trace elements in each sampling site was approximately at medium risk level (10 -5 to 10 -4 ). The areas in the south (S4, S13, and S16) and northeast (S8, S18, and S19) of Honghu Lake were regarded as the risk priority control areas. However, the corresponding maximum memberships of integrated carcinogenic risk in S1, S3, S10-S13, S15, and S18 were of relatively low credibility (50-60%), and may mislead the decision-makers in identifying the risk priority areas. Results of fuzzy assessment presented the subordinate grade and corresponding reliability of risk, and provided more full-scale results for decision-makers, which made up for the deficiency of certainty assessment to a certain extent.

  4. Comparison of time-dependent changes in the surface hardness of different composite resins

    Science.gov (United States)

    Ozcan, Suat; Yikilgan, Ihsan; Uctasli, Mine Betul; Bala, Oya; Kurklu, Zeliha Gonca Bek

    2013-01-01

    Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vicker's hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukey's test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P composite resin Filtek Silorane showed adequate hardness ratio, the use of incremental technic during application is more important than methacrylate based composites. PMID:24966724

  5. A Multiscale Finite Element Model Validation Method of Composite Cable-Stayed Bridge Based on Structural Health Monitoring System

    Directory of Open Access Journals (Sweden)

    Rumian Zhong

    2015-01-01

    Full Text Available A two-step response surface method for multiscale finite element model (FEM updating and validation is presented with respect to Guanhe Bridge, a composite cable-stayed bridge in the National Highway number G15, in China. Firstly, the state equations of both multiscale and single-scale FEM are established based on the basic equation in structural dynamic mechanics to update the multiscale coupling parameters and structural parameters. Secondly, based on the measured data from the structural health monitoring (SHM system, a Monte Carlo simulation is employed to analyze the uncertainty quantification and transmission, where the uncertainties of the multiscale FEM and measured data were considered. The results indicate that the relative errors between the calculated and measured frequencies are less than 2%, and the overlap ratio indexes of each modal frequency are larger than 80% without the average absolute value of relative errors. These demonstrate that the proposed method can be applied to validate the multiscale FEM, and the validated FEM can reflect the current conditions of the real bridge; thus it can be used as the basis for bridge health monitoring, damage prognosis (DP, and safety prognosis (SP.

  6. 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.

  7. Experimental verification of active IR stealth technology by controlling the surface temperature using a thermoelectric element

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Geon; Han, Kuk Il; Choi, Jun Hyuk; Kim, Tae Kuk [Dept. of Mechanical Engineering, Chung Ang University, Seoul (Korea, Republic of)

    2016-10-15

    In this paper, we propose a technique for IR low-observability that uses an active IR signal tuning through the real time control of the object surface temperature according to the varying background environment. This is achieved by applying the proper object surface temperature obtained to result in the minimum radiance difference between the object and the background. Experimental verification by using the thermoelectric temperature control element shows that the IR radiance contrast between the object and the background can be reduced up to 99% during the night and up to 95% during the day time as compared to the un-tuned original radiance contrast values. The stealth technology demonstrated in this paper may be applied for many military systems needed for the IR stealth performance when a suitable temperature control unit is developed.

  8. Experimental verification of active IR stealth technology by controlling the surface temperature using a thermoelectric element

    International Nuclear Information System (INIS)

    Kim, Dong Geon; Han, Kuk Il; Choi, Jun Hyuk; Kim, Tae Kuk

    2016-01-01

    In this paper, we propose a technique for IR low-observability that uses an active IR signal tuning through the real time control of the object surface temperature according to the varying background environment. This is achieved by applying the proper object surface temperature obtained to result in the minimum radiance difference between the object and the background. Experimental verification by using the thermoelectric temperature control element shows that the IR radiance contrast between the object and the background can be reduced up to 99% during the night and up to 95% during the day time as compared to the un-tuned original radiance contrast values. The stealth technology demonstrated in this paper may be applied for many military systems needed for the IR stealth performance when a suitable temperature control unit is developed

  9. Intelligent detection of cracks in metallic surfaces using a waveguide sensor loaded with metamaterial elements.

    Science.gov (United States)

    Ali, Abdulbaset; Hu, Bing; Ramahi, Omar

    2015-05-15

    This work presents a real life experiment of implementing an artificial intelligence model for detecting sub-millimeter cracks in metallic surfaces on a dataset obtained from a waveguide sensor loaded with metamaterial elements. Crack detection using microwave sensors is typically based on human observation of change in the sensor's signal (pattern) depicted on a high-resolution screen of the test equipment. However, as demonstrated in this work, implementing artificial intelligence to classify cracked from non-cracked surfaces has appreciable impact in terms of sensing sensitivity, cost, and automation. Furthermore, applying artificial intelligence for post-processing data collected from microwave sensors is a cornerstone for handheld test equipment that can outperform rack equipment with large screens and sophisticated plotting features. The proposed method was tested on a metallic plate with different cracks and the obtained experimental results showed good crack classification accuracy rates.

  10. Hydrodynamics of free surface flows modelling with the finite element method

    CERN Document Server

    Hervouet, Jean-Michel

    2007-01-01

    A definitive guide for accurate state-of-the-art modelling of free surface flows Understanding the dynamics of free surface flows is the starting point of many environmental studies, impact studies, and waterworks design. Typical applications, once the flows are known, are water quality, dam impact and safety, pollutant control, and sediment transport. These studies used to be done in the past with scale models, but these are now being replaced by numerical simulation performed by software suites called "hydro-informatic systems". The Telemac system is the leading software package worldwide, and has been developed by Electricité de France and Jean-Michel Hervouet, who is the head and main developer of the Telemac project. Written by a leading authority on Computational Fluid Dynamics, the book aims to provide environmentalists, hydrologists, and engineers using hydro-informatic systems such as Telemac and the finite element method, with the knowledge of the basic principles, capabilities, different hypothese...

  11. Pluto and Charon: Surface Colors and Compositions - A Hypothesis

    Science.gov (United States)

    Cruikshank, D. P.

    2016-01-01

    The surface of Pluto displays an array of colors ranging from yellow to red to brown, while the surface of Charon is largely gray with a north polar zone of red color similar to regions on Pluto. Pluto's surface shows layers of intensely colored material in tilted and transported blocks, and fractured geo-graphical units. This arrangement suggests episodes of formation or deposition of that material interspersed with episodes of emplacement of ices having little or no color. The ices identified on the surfaces of these two bodies (N2, CH4, CO, C2H6, H2O on Pluto, and H2O and NH3 on Charon) are colorless, as are nearly all ices in a powdery state. The colors on Pluto probably arise from the in situ formation of a macro-molecular carbonaceous material generated by energetic processing of the ices on the surface. Laboratory experiments producing refractory tholins particularly relevant to Pluto explored the chemistry of both UV and low-energy electron bombardment of a mix of Pluto ices (N2:CH4:CO = 100:1:1). We can term this Pluto ice tholin PIT. Water ice in the crystalline state characterizes Charon's surface, and while most of Charon's surface is neutral in color, with geometric albedo approximately 0.38, the polar zone and a light cover of fainter but similar reddish color over some surface regions suggest a common origin with the colored material on Pluto. NH3 or NH3 x nH2O was identified from disk-integrated Earth-based spectra, and a few concentrated NH3 exposures have been found in the New Horizons spectral images.

  12. Graphitic carbon nitride nanosheet for photocatalytic hydrogen production: The impact of morphology and element composition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhao; Zhang, Yijie [Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and Chemistry, China University of Geosciences Wuhan, 388 Lumo Road, Wuhan 430074 (China); Lu, Luhua, E-mail: lhlu@cug.edu.cn [Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and Chemistry, China University of Geosciences Wuhan, 388 Lumo Road, Wuhan 430074 (China); Zhejiang institute, China University of Geosciences Wuhan, Hangzhou 311305 (China); Si, Yanjie; Zhang, Si [Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and Chemistry, China University of Geosciences Wuhan, 388 Lumo Road, Wuhan 430074 (China); Chen, Ying [Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and Chemistry, China University of Geosciences Wuhan, 388 Lumo Road, Wuhan 430074 (China); Zhejiang institute, China University of Geosciences Wuhan, Hangzhou 311305 (China); Dai, Kai, E-mail: daikai94@ustc.edu.cn [College of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000 (China); Duan, Ping [Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and Chemistry, China University of Geosciences Wuhan, 388 Lumo Road, Wuhan 430074 (China); Zhejiang institute, China University of Geosciences Wuhan, Hangzhou 311305 (China); Duan, Limei [Inner Mongolia Key Lab of Chemistry of Natural Products and Synthesis of Functional Molecules, College of Chemistry and Chemical Engineering, Inner Mongolia University for the Nationalities, Tongliao 028000 (China); Liu, Jinghai, E-mail: jhliu2008@sinano.ac.cn [Inner Mongolia Key Lab of Chemistry of Natural Products and Synthesis of Functional Molecules, College of Chemistry and Chemical Engineering, Inner Mongolia University for the Nationalities, Tongliao 028000 (China)

    2017-01-01

    Highlights: • g-C{sub 3}N{sub 4} with tunable morphology was prepared by varying pyrolysis time. • g-C{sub 3}N{sub 4} showed reduced recombination of photogenerated electrons and holes. • g-C{sub 3}N{sub 4} showed enhanced photocatalytic hydrogen evolution activity. - Abstract: The intrinsic morphology and basal plane defects on g-C{sub 3}N{sub 4} nanosheet have important influences on its electronic structures and photocatalytic activity. In this work, we report extending thermal treatment time of g-C{sub 3}N{sub 4} at 550 °C not only change the morphology of g-C{sub 3}N{sub 4} but also element composition of g-C{sub 3}N{sub 4}. The morphology variation results in largely increased SSA from 40.22 to 117.27 m{sup 2} g{sup −1}, obviously reduced pore size from 3.99 to 2.77 nm for g-C{sub 3}N{sub 4} and formation of in-plane holes. Moreover, composition variation of g-C{sub 3}N{sub 4} has also been found to have changed as the pyrolysis time extended. These changes have significant impact on the optical properties and photoelectrical characters of g-C{sub 3}N{sub 4}, which were investigated by UV-DSR, PL and Photocurrent measurement. The photocatalytic activity of g-C{sub 3}N{sub 4} obtained via 9 h thermal treatment at 550 °C has shown highest photocatalytic activity, which is 1.77 times than that of g-C{sub 3}N{sub 4} obtained via 3 h thermal treatment under visible irradiation and 1.99 times under UV irradiation respectively.

  13. Graphitic carbon nitride nanosheet for photocatalytic hydrogen production: The impact of morphology and element composition

    International Nuclear Information System (INIS)

    Zhang, Zhao; Zhang, Yijie; Lu, Luhua; Si, Yanjie; Zhang, Si; Chen, Ying; Dai, Kai; Duan, Ping; Duan, Limei; Liu, Jinghai

    2017-01-01

    Highlights: • g-C_3N_4 with tunable morphology was prepared by varying pyrolysis time. • g-C_3N_4 showed reduced recombination of photogenerated electrons and holes. • g-C_3N_4 showed enhanced photocatalytic hydrogen evolution activity. - Abstract: The intrinsic morphology and basal plane defects on g-C_3N_4 nanosheet have important influences on its electronic structures and photocatalytic activity. In this work, we report extending thermal treatment time of g-C_3N_4 at 550 °C not only change the morphology of g-C_3N_4 but also element composition of g-C_3N_4. The morphology variation results in largely increased SSA from 40.22 to 117.27 m"2 g"−"1, obviously reduced pore size from 3.99 to 2.77 nm for g-C_3N_4 and formation of in-plane holes. Moreover, composition variation of g-C_3N_4 has also been found to have changed as the pyrolysis time extended. These changes have significant impact on the optical properties and photoelectrical characters of g-C_3N_4, which were investigated by UV-DSR, PL and Photocurrent measurement. The photocatalytic activity of g-C_3N_4 obtained via 9 h thermal treatment at 550 °C has shown highest photocatalytic activity, which is 1.77 times than that of g-C_3N_4 obtained via 3 h thermal treatment under visible irradiation and 1.99 times under UV irradiation respectively.

  14. 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

  15. Elemental composition of platelets. Part I. Sampling and sample preparation of platelets for trace-element analysis

    International Nuclear Information System (INIS)

    Iyengar, G.V.; Borberg, H.; Kasperek, K.; Kiem, J.; Siegers, M.; Feinendegen, L.E.; Gross, R.

    1979-01-01

    Sampling of platelets for trace-element analysis poses special problems: obtaining adequate sample materials, achieving a sufficient cell purity, preserving viability (integrity), correcting for trapped plasma, and controlling contamination. We used a blood-cell separator for the primary isolation of platelets from blood, and differential centrifugation in natural plasma to further isolate them. The pyrimidopyrimidine RA233 was used as a stabilizer to maintain viability. 131 I-labeled human serum albumin was used to estimate trapped plasma. Contamination was controlled by using five-times-distilled water to simulate donor's blood in the system and by comparing three fractions: the serum, the first portion of the platelet-rich plasma, and the supernatant plasma after the final centrifugation. Neutron activation analysis was used for the elemental analysis. A single differential centrifugation of the platelet-rich plasma from the blood-cell separator at 400 x g for 8 min was optimum (mean mass fractions: erythrocytes/platelets < 5 mg/g and leukocytes/platelets < 20 mg/g). The trapped plasma in the wet platelet samples amounted to about 0.40 g/g. No appreciable contamination from the sampling system was found for the elements Ag, Cd, Co, Cr, Cs, Cu, Fe, Mo, Rb, Sb, Se, and Zn. 2 figures, 3 tables

  16. Polishing and toothbrushing alters the surface roughness and gloss of composite resins.

    Science.gov (United States)

    Kamonkhantikul, Krid; Arksornnukit, Mansuang; Takahashi, Hidekazu; Kanehira, Masafumi; Finger, Werner J

    2014-01-01

    This study aimed to investigate the surface roughness and gloss of composite resins after using two polishing systems and toothbrushing. Six composite resins (Durafill VS, Filtek Z250, Filtek Z350 XT, Kalore, Venus Diamond, and Venus Pearl) were evaluated after polishing with two polishing systems (Sof-Lex, Venus Supra) and after toothbrushing up to 40,000 cycles. Surface roughness (Ra) and gloss were determined for each composite resin group (n=6) after silicon carbide paper grinding, polishing, and toothbrushing. Two-way ANOVA indicated significant differences in both Ra and gloss between measuring stages for the composite resins tested, except Venus Pearl, which showed significant differences only in gloss. After polishing, the Filtek Z350 XT, Kalore, and Venus Diamond showed significant increases in Ra, while all composite resin groups except the Filtek Z350 XT and Durafill VS with Sof-Lex showed increases in gloss. After toothbrushing, all composite resin demonstrated increases in Ra and decreases in gloss.

  17. Finite element analysis of Al 2024/Cu-Al-Ni shape memory alloy composites with defects/cracks

    Science.gov (United States)

    Kotresh, M.; Benal, M. M., Dr; Siddalinga Swamy, N. H., Dr

    2018-02-01

    In this work, a numerical approach to predict the stress field behaviour of defect/crack in shape memory alloy (SMA) particles reinforced composite known as the adaptive composite is presented. Simulation is based on the finite element method. The critical stress field approach was used to determine the stresses around defect/crack. Thereby stress amplification issue is being resolved. In this paper, the effect volume % of shape memory alloy and shape memory effect of reinforcement for as-cast and SME trained composites are examined and discussed. Shape memory effect known as training is achieved by pre-straining of reinforcement particles by equivalent changes in their expansion coefficients.

  18. Multilayered nanoclusters of platinum and gold: insights on electrodeposition pathways, electrocatalysis, surface and bulk compositional properties

    CSIR Research Space (South Africa)

    Mkwizu, TS

    2013-06-01

    Full Text Available Electrochemical, surface and bulk compositional properties of multilayered nanoclusters of Pt and Au, electrochemically deposited on glassy carbon under conditions involving sequential surface–limited redox–replacement reactions (performed at open...

  19. Surface water connectivity drives richness and composition of Arctic lake fish assemblages

    Science.gov (United States)

    Laske, Sarah M.; Haynes, Trevor B.; Rosenberger, Amanda E.; Koch, Joshua C.; Wipfli, Mark S.; Whitman, Matthew; Zimmerman, Christian E.

    2016-01-01

    Surface water connectivity can influence the richness and composition of fish assemblages, particularly in harsh environments where colonisation factors and access to seasonal refugia are required for species persistence.

  20. Efficacy of polishing kits on the surface roughness and color stability of different composite resins.

    Science.gov (United States)

    Kocaagaoglu, H; Aslan, T; Gürbulak, A; Albayrak, H; Taşdemir, Z; Gumus, H

    2017-05-01

    Different polishing kits may have different effects on the composite resin surfaces. The aim of this study was to evaluate the surface roughness and color stability of four different composites which was applied different polishing technique. Thirty specimens were made for each composite resin group (nanohybrid, GrandioSo-GS; nanohybrid, Clearfil Majesty Esthetic-CME; hybrid, Valux Plus-VP; micro-hybrid, Ruby Comp-RC; [15 mm in diameter and 2 mm height]), with the different monomer composition and particle size from a total of 120 specimens. Each composite group was divided into three subgroups (n = 10). The first subgroup of the each composite subgroups served as control (C) and had no surface treatment. The second subgroup of the each composite resin groups was polished with finishing discs (Bisco Finishing Discs; Bisco Inc., Schaumburg, IL, USA). The third subgroup of the each composite resin was polished with polishing wheel (Enhance and PoGo, Dentsply, Konstanz, Germany). The surface roughness and the color differences measurement of the specimens were made and recorded. The data were compared using Kruskal-Wallis test, and regression analysis was used in order to examine the correlation between surface roughness and color differences of the specimens (α = 0.05). The Kruskal-Wallis test indicated significant difference among the composite resins in terms of ΔE (P composite resins in terms of surface roughness (P > 0.05). Result of the regression analysis indicated statistically significant correlation between Ra and ΔE values (P < 0.05, r2 = 0.74). The findings of the present study have clinical relevance in the choice of polishing kits used.

  1. A new discrete-element approach for the assessment of the seismic resistance of composite reinforced concrete-masonry buildings

    International Nuclear Information System (INIS)

    Calio, I.; Cannizzaro, F.; Marletta, M.; Panto, B.; D'Amore, E.

    2008-01-01

    In the present study a new discrete-element approach for the evaluation of the seismic resistance of composite reinforced concrete-masonry structures is presented. In the proposed model, unreinforced masonry panels are modelled by means of two-dimensional discrete-elements, conceived by the authors for modelling masonry structures, whereas the reinforced concrete elements are modelled by lumped plasticity elements interacting with the masonry panels through nonlinear interface elements. The proposed procedure was adopted for the assessment of the seismic response of a case study confined-masonry building which was conceived to be a typical representative of a wide class of residential buildings designed to the requirements of the 1909 issue of the Italian seismic code and widely adopted in the aftermath of the 1908 earthquake for the reconstruction of the cities of Messina and Reggio Calabria

  2. Surface Roughness and Gloss of Actual Composites as Polished With Different Polishing Systems.

    Science.gov (United States)

    Rodrigues-Junior, S A; Chemin, P; Piaia, P P; Ferracane, J L

    2015-01-01

    This in vitro study evaluated the effect of polishing with different polishing systems on the surface roughness and gloss of commercial composites. One hundred disk-shaped specimens (10 mm in diameter × 2 mm thick) were made with Filtek P-90, Filtek Z350 XT, Opallis, and Grandio. The specimens were manually finished with #400 sandpaper and polished by a single operator using three multistep systems (Superfix, Diamond Pro, and Sof-lex), one two-step system (Polidores DFL), and one one-step system (Enhance), following the manufacturer's instructions. The average surface roughness (μm) was measured with a surface profilometer (TR 200 Surface Roughness Tester), and gloss was measured using a small-area glossmeter (Novo-Curve, Rhopoint Instrumentation, East Sussex, UK). Data were analyzed by two-way analysis of variance and Tukey's test (α=0.05). Statistically significant differences in surface roughness were identified by varying the polishing systems (pGloss was influenced by the composites (pone-step system, Enhance, produced the lowest gloss for all composites. Surface roughness and gloss were affected by composites and polishing systems. The interaction between both also influenced these surface characteristics, meaning that a single polishing system will not behave similarly for all composites. The multistep systems produced higher gloss, while the one-step system produced the highest surface roughness and the lowest gloss of all.

  3. Effects of 35% Carbamide Peroxide Gel on Surface Roughness and Hardness of Composite Resins

    OpenAIRE

    Sharafeddin, F.; Jamalipour, GR.

    2010-01-01

    Objective: Bleaching agents may not be safe for dental materials. The purpose of this in-vitro study was to evaluate the effects of Opalescent Quick ?in-office bleaching gel? containing 35% carbamide peroxide on the surface roughness and hardness of microfilled (Heliomolar) and hybride (Spectrum TPH) composite resins. Materials and Methods: Twenty specimens of Spectrum TPH composite resins and twenty Heliomolar composite resins were fabricated using a metallic ring (6.5 mm diameter and 2.5 mm...

  4. Simultaneous tuning of chemical composition and topography of copolymer surfaces: micelles as building blocks.

    Science.gov (United States)

    Zhao, Ning; Zhang, Xiaoyan; Zhang, Xiaoli; Xu, Jian

    2007-05-14

    A simple method is described for controlling the surface chemical composition and topography of the diblock copolymer poly(styrene)-b-poly(dimethylsiloxane)(PS-b-PDMS) by casting the copolymer solutions from solvents with different selectivities. The surface morphology and chemical composition were characterized by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively, and the wetting behavior was studied by water contact angle (CA) and sliding angle (SA) and by CA hysteresis. Chemical composition and morphology of the surface depend on solvent properties, humidity of the air, solution concentration, and block lengths. If the copolymer is cast from a common solvent, the resultant surface is hydrophobic, with a flat morphology, and dominated by PDMS on the air side. From a PDMS-selective solvent, the surface topography depends on the morphology of the micelles. Starlike micelles give rise to a featureless surface nearly completely covered by PDMS, while crew-cut-like micelles lead to a rough surface with a hierarchical structure that consists partly of PDMS. From a PS-selective solvent, however, surface segregation of PDMS was restricted, and the surface morphology can be controlled by vapor-induced phase separation. On the basis of the tunable surface roughness and PDMS concentration on the air side, water repellency of the copolymer surface could be tailored from hydrophobic to superhydrophobic. In addition, reversible switching behavior between hydrophobic and superhydrophobic can be achieved by exposing the surface to solvents with different selectivities.

  5. Elemental composition of current automotive braking materials and derived air emission factors

    Science.gov (United States)

    Hulskotte, J. H. J.; Roskam, G. D.; Denier van der Gon, H. A. C.

    2014-12-01

    Wear-related PM emissions are an important constituent of total PM emissions from road transport. Due to ongoing (further) exhaust emission reduction wear emissions may become the dominant PM source from road transport in the near future. The chemical composition of the wear emissions is crucial information to assess the potential health relevance of these PM emissions. Here we provide an elemental composition profile of brake wear emissions as used in the Netherlands in 2012. In total, 65 spent brake pads and 15 brake discs were collected in car maintenance shops from in-use personal cars vehicles and analyzed with XRF for their metal composition (Fe, Cu, Zn, Sn, Al, Si, Zr, Ti, Sb, Cr, Mo, Mn, V, Ni, Bi, W, P, Pb and Co). Since car, engine and safety regulations are not nationally determined but controlled by European legislation the resulting profiles will be representative for the European personal car fleet. The brake pads contained Fe and Cu as the dominant metals but their ratio varied considerably, other relatively important metals were Sn, Zn and Sb. Overall a rather robust picture emerged with Fe, Cu, Zn and Sn together making up about 80-90% of the metals present in brake pads. Because the XRF did not give information on the contents of other material such as carbon, oxygen and sulphur, a representative selection of 9 brake pads was further analyzed by ICP-MS and a carbon and sulphur analyzer. The brake pads contained about 50% of non-metal material (26% C, 3% S and the remainder mostly oxygen and some magnesium). Based on our measurements, the average brake pad profile contained 20% Fe, 10% Cu, 4% Zn and 3% Sn as the dominant metals. The brake discs consisted almost entirely of metal with iron being the dominant metal (>95%) and only traces of other metals (<1% for individual metals). Non-metal components in the discs were 2-3% Silicon and, according to literature, ∼3% carbon. The robust ratio between Fe and Cu as found on kerbsides has been used to

  6. 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

  7. All-cellulose composites of regenerated cellulose fibres by surface selective dissolution

    NARCIS (Netherlands)

    Soykeabkaew, N.; Nishino, T.; Peijs, Ton

    2009-01-01

    All-cellulose composites of Lyocell and high modulus/strength cellulose fibres were successfully prepared using a surface selective dissolution method. The effect of immersion time of the fibres in the solvent during composite's preparation and the effect of the starting fibre's structure on their

  8. Effect of processing method on surface and weathering characteristics of wood-flour/HDPE composites

    Science.gov (United States)

    Nicole M. Stark; Laurent M. Matuana; Craig M. Clemons

    2004-01-01

    Wood-plastic lumber is promoted as a low maintenance high-durability product. When exposed to accelerated weathering, however, wood-plastic composites may experience a color change and/or loss in mechanical properties. Different methods of manufacturing wood-plastic composites lead to different surface characteristics, which can influence weathering, In this study, 50...

  9. Rare earth, major and trace element composition of Leg 127 sediments

    Science.gov (United States)

    Murray, R.W.; Buchholtz ten Brink, Marilyn R.; Brumsack, Hans-Juergen; Gerlach, David C.; Russ III, G. Price

    1992-01-01

    The relative effects of paleoceanographic and paleogeographic variations, sediment lithology, and diagenetic processes on the final preserved chemistry of Japan Sea sediments are evaluated by investigating the rare earth element (REE), major element, and trace element concentrations in 59 squeeze-cake whole-round and 27 physical-property sample residues from Sites 794, 795, and 797, cored during ODP Leg 127. The most important variation in sedimentary chemical composition is the increase in SiO2 concentration through the Pliocene diatomaceous sequences, which dilutes most other major and trace element components by various degrees. This biogenic input is largest at Site 794 (Yamato Basin), moderately developed at Site 797 (Yamato Basin), and of only minor importance at Site 795 (Japan Basin), potentially reflecting basinal contrasts in productivity with the Yamato Basin recording greater biogenic input than the Japan Basin and with the easternmost sequence of Site 794 lying beneath the most productive waters. There are few systematic changes in solid-phase chemistry resulting from the opal-A/opal-CT or opal-CT/quartz silica phase transformations. Most major and trace element concentrations are controlled by the aluminosilicate fraction of the sediment, although the effects of diagenetic silica phases and manganese carbonates are of localized importance. REE total abundances (IREE) in the Japan Sea are strongly dependent upon the paleoceanographic position of a given site with respect to terrigenous and biogenic sources. REE concentrations at Site 794 overall correspond well to aluminosilicate chemical indices and are strongly diluted by SiO2 within the upper Miocene-Pliocene diatomaceous sequence. Eu/Eu* values at Site 794 reach a maximum through the diatomaceous interval as well, most likely suggesting an association of Eu/Eu* with the siliceous component, or reflecting slight incorporation of a detrital feldspar phase. XREE at Site 795 also is affiliated strongly

  10. The effect of different polishing systems on surface roughness and gloss of various resin composites.

    Science.gov (United States)

    Da Costa, Juliana; Ferracane, Jack; Paravina, Rade D; Mazur, Rui Fernando; Roeder, Leslie

    2007-01-01

    The purpose of this in vitro study was to evaluate the surface finish and gloss of five direct resin composites polished with six polishing systems. One hundred and fifty disk-shaped composite specimens (D=10.0 mm, 2-mm-thick, N=30 per material) were made. One side of each specimen was finished with a 16-fluted carbide finishing bur and then polished. Five specimens of each resin composite were randomly assigned to one of the six polishing systems. The surface roughness and gloss were measured with a surface profilometer and a glossmeter. The results were analyzed by two-way analysis of variance and Tukey's t-test (pgloss values between the composites and the polishing systems (p gloss value was recorded for Supreme + Pogo; the lowest was recorded for Z100 + Jiffy. Pogo showed the highest gloss values for all composites. The nanofill (Supreme) and minifill (Esthet-X) composites presented a surface roughness comparable to a microfill (Durafill), independent of the polishing system used, and a gloss comparable to a microfill, when polished with a one-step system (Pogo). As compared with the multiple-step systems, the smoothest surfaces and the highest gloss values were achieved using the one-step system (Pogo) for all the evaluated composites.

  11. An extended validation of the last generation of particle finite element method for free surface flows

    Science.gov (United States)

    Gimenez, Juan M.; González, Leo M.

    2015-03-01

    In this paper, a new generation of the particle method known as Particle Finite Element Method (PFEM), which combines convective particle movement and a fixed mesh resolution, is applied to free surface flows. This interesting variant, previously described in the literature as PFEM-2, is able to use larger time steps when compared to other similar numerical tools which implies shorter computational times while maintaining the accuracy of the computation. PFEM-2 has already been extended to free surface problems, being the main topic of this paper a deep validation of this methodology for a wider range of flows. To accomplish this task, different improved versions of discontinuous and continuous enriched basis functions for the pressure field have been developed to capture the free surface dynamics without artificial diffusion or undesired numerical effects when different density ratios are involved. A collection of problems has been carefully selected such that a wide variety of Froude numbers, density ratios and dominant dissipative cases are reported with the intention of presenting a general methodology, not restricted to a particular range of parameters, and capable of using large time-steps. The results of the different free-surface problems solved, which include: Rayleigh-Taylor instability, sloshing problems, viscous standing waves and the dam break problem, are compared to well validated numerical alternatives or experimental measurements obtaining accurate approximations for such complex flows.

  12. Finite Element Method Analysis of An Out Flow With Free Surface In Transition Zones

    Science.gov (United States)

    Saoula, R. Iddir S.; Mokhtar, K. Ait

    The object of this work is to present this part of the fluid mechanics that relates to out-flows of the fluid to big speeds in transitions. Results usually gotten by the classic processes can only have a qualitative aspect. The method fluently used for the count of these out-flows to big speeds is the one of characteristics, this approach remains interesting so much that doesn't appear within the out-flow of intersections of shock waves, as well as of reflections of these. In the simple geometry case, the method of finite differences satisfying result, But when the complexity of this geometry imposes itself, it is the method of finite elements that is proposed to solve this type of prob- lem, in particular for problems Trans critic. The goal of our work is to analyse free surface flows in channels no prismatic has oblong transverse section in zone of tran- sition. (Convergent, divergent). The basic mathematical model of this study is Saint Venant derivatives partial equations. To solve these equations we use the finite ele- ment method, the element of reference is the triangular element with 6 nodes which are quadratic in speed and linear in height (pressure). Our results and their obtains by others are very close to experimental results.

  13. Surface roughness of orthodontic band cements with different compositions

    Directory of Open Access Journals (Sweden)

    Françoise Hélène van de Sande

    2011-06-01

    Full Text Available OBJECTIVES: The present study evaluated comparatively the surface roughness of four orthodontic band cements after storage in various solutions. MATERIAL AND METHODS: Eight standardized cylinders were made from 4 materials: zinc phosphate cement (ZP, compomer (C, resin-modified glass ionomer cement (RMGIC and resin cement (RC. Specimens were stored for 24 h in deionized water and immersed in saline (pH 7.0 or 0.1 M lactic acid solution (pH 4.0 for 15 days. Surface roughness readings were taken with a profilometer (Surfcorder SE1200 before and after the storage period. Data were analyzed by two-way ANOVA and Tukey's test (comparison among cements and storage solutions or paired t-test (comparison before and after the storage period at 5% significance level. RESULTS: The values for average surface roughness were statistically different (pRMGIC>C>R (p0.05. Compared to the current threshold (0.2 µm related to biofilm accumulation, both RC and C remained below the threshold, even after acidic challenge by immersion in lactic acid solution. CONCLUSIONS: Storage time and immersion in lactic acid solution increased the surface roughness of the majority of the tested cements. RC presented the smoothest surface and it was not influenced by storage conditions.

  14. Finite element modelling of Plantar Fascia response during running on different surface types

    Science.gov (United States)

    Razak, A. H. A.; Basaruddin, K. S.; Salleh, A. F.; Rusli, W. M. R.; Hashim, M. S. M.; Daud, R.

    2017-10-01

    Plantar fascia is a ligament found in human foot structure located beneath the skin of human foot that functioning to stabilize longitudinal arch of human foot during standing and normal gait. To perform direct experiment on plantar fascia seems very difficult since the structure located underneath the soft tissue. The aim of this study is to develop a finite element (FE) model of foot with plantar fascia and investigate the effect of the surface hardness on biomechanical response of plantar fascia during running. The plantar fascia model was developed using Solidworks 2015 according to the bone structure of foot model that was obtained from Turbosquid database. Boundary conditions were set out based on the data obtained from experiment of ground reaction force response during running on different surface hardness. The finite element analysis was performed using Ansys 14. The results found that the peak of stress and strain distribution were occur on the insertion of plantar fascia to bone especially on calcaneal area. Plantar fascia became stiffer with increment of Young’s modulus value and was able to resist more loads. Strain of plantar