Sample records for composition distribution life

  1. SPECIES COMPOSITION, DISTRIBUTION, LIFE FORMS AND FOLK NOMENCLATURE OF FOREST AND COMMON LAND PLANTS OF WESTERN CHITWAN, NEPAL

    PubMed Central

    Dangol, D. R.

    2012-01-01

    This paper enumerates 349 plant species belonging to 77 families of vascular plants collected in the winter seasons of 1996 and 2000 by the flora teams of the Population and Ecology Research Laboratory, Nepal. Of the total species, 249 species belong to dicotyledons, 87 species to monocotyledons and 13 species to pteridophytes. Among the families, dicotyledons contributed the highest number of families (55 in number) followed by monocotyledons and pteridophytes. In the study areas, species composition varies with the type of habitats in the study plots. Some species are unique in distribution. The highest unique species are contributed by common lands (87 spp.), followed by the Chitwan National Park forest (36 spp.) and Tikauli forest (32 spp.). Ageratum houstonianum Mill., Cynodon dactylon (L.) Pers., Imperata cylindrica (L.) Beauv., Rungia parviflora (Retz.) Nees, Saccharum spontaneum L. and Thelypteris auriculata (J. Sm.) K. Iwats are the most common species across all the research blocks. Of the listed plants, many plants have local names either in Nepalese or other tribal languages. Plants are named in different ways on the basis of habit, habitat, smell, taste, and morphological characters of the plants, which are also the basis of nomenclature in plant taxonomy. PMID:22962539

  2. Distribution-Free Life Test Sampling Plans

    Microsoft Academic Search

    Richard E. Barlow; Shanti S. Gupta

    1966-01-01

    This paper describes life test sampling plans which assume only that the life distribution has increasing or decreasing failure rate. Tables are presented showing the minimum number of items necessary to assure a specified mean life or percentile life when the experiment time is fixed in advance.

  3. Effect of Individual Component Life Distribution on Engine Life Prediction

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.; Hendricks, Robert C.; Soditus, Sherry M.

    2003-01-01

    The effect of individual engine component life distributions on engine life prediction was determined. A Weibull-based life and reliability analysis of the NASA Energy Efficient Engine was conducted. The engine s life at a 95 and 99.9 percent probability of survival was determined based upon the engine manufacturer s original life calculations and assumed values of each of the component s cumulative life distributions as represented by a Weibull slope. The lives of the high-pressure turbine (HPT) disks and blades were also evaluated individually and as a system in a similar manner. Knowing the statistical cumulative distribution of each engine component with reasonable engineering certainty is a condition precedent to predicting the life and reliability of an entire engine. The life of a system at a given reliability will be less than the lowest-lived component in the system at the same reliability (probability of survival). Where Weibull slopes of all the engine components are equal, the Weibull slope had a minimal effect on engine L(sub 0.1) life prediction. However, at a probability of survival of 95 percent (L(sub 5) life), life decreased with increasing Weibull slope.

  4. Fatigue life characterization for piezoelectric macrofiber composites

    NASA Astrophysics Data System (ADS)

    Henslee, Isaac A.; Miller, David A.; Tempero, Tyler

    2012-10-01

    In an effort to aid the investigation into lightweight and reliable materials for actuator design, a study was developed to characterize the temperature-dependent lifetime performance of a piezoelectric macrofiber composite (MFC). MFCs are thin rectangular patches of polyimide film, epoxy and a single layer of rectangular lead zirconium titanate (PZT) fibers. In this study, the useful life of the MFC is characterized to determine the effect of temperature on the performance of the composite as it is fatigued by cyclic piezoelectric excitation. The test specimen consists of the MFC laminated to a cantilevered stainless steel beam. Beam strain and tip displacement measurements are used as a basis for determining the performance of the MFC as it is cyclically actuated under various operating temperatures. The temperature of the beam laminate is held constant and then cycled to failure, or 250 million cycles, in order to determine the useful life of the MFC over a temperature range from - 15 to 145?°C. The results of the experiments show a strong temperature dependence of the operational life for the MFC. Damage inside the composite was identified through in situ visual inspection and during post-test microstructural observation; however, no degradation in operational performance was identified as it was cyclically actuated up to the point of failure, regardless of temperature or actuation cycle number.

  5. The compositional distribution of asteroids

    NASA Astrophysics Data System (ADS)

    DeMeo, F.; Carry, B.; Alexander, C.; Walsh, K.; Chapman, C.

    2014-07-01

    Each compositional class of asteroid is a relic of the temperature and composition conditions in which it formed. The current distribution reveals the history of the Solar System, and each body acts as a marker of any mixing that occurred since formation. The remnant of a primordial temperature gradient, seen as transition from the S class to C class dominating in different regions of the asteroid belt has been a paradigm for three decades [1-4]. Today, we are armed with major advancements from the past decade that have revolutionized the field of asteroids in areas such as discovery, physical characterization, and dynamical models. A new and more detailed compositional map [5,6] created with data from the Sloan Digital Sky Survey [7] allows us to re-examine compositional trends in the main asteroid belt and what the physical and dynamical implications might be. This talk is related to recent work from DeMeo & Carry 2013, 2014 [5,6] and an upcoming chapter of the "Asteroids IV" book in 2015.

  6. A distributed program composition system

    NASA Technical Reports Server (NTRS)

    Brown, Robert L.

    1989-01-01

    A graphical technique for creating distributed computer programs is investigated and a prototype implementation is described which serves as a testbed for the concepts. The type of programs under examination is restricted to those comprising relatively heavyweight parts that intercommunicate by passing messages of typed objects. Such programs are often presented visually as a directed graph with computer program parts as the nodes and communication channels as the edges. This class of programs, called parts-based programs, is not well supported by existing computer systems; much manual work is required to describe the program to the system, establish the communication paths, accommodate the heterogeneity of data types, and to locate the parts of the program on the various systems involved. The work described solves most of these problems by providing an interface for describing parts-based programs in this class in a way that closely models the way programmers think about them: using sketches of diagraphs. Program parts, the computational modes of the larger program system are categorized in libraries and are accessed with browsers. The process of programming has the programmer draw the program graph interactively. Heterogeneity is automatically accommodated by the insertion of type translators where necessary between the parts. Many decisions are necessary in the creation of a comprehensive tool for interactive creation of programs in this class. Possibilities are explored and the issues behind such decisions are presented. An approach to program composition is described, not a carefully implemented programming environment. However, a prototype implementation is described that can demonstrate the ideas presented.

  7. Composites of porous metal and solid lubricants increase bearing life

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.

    1967-01-01

    Self-lubricating composites of porous nickel and nickel-chromium alloy impregnated with a barium fluoride-calcium fluoride eutectic, and a thin film of solid lubricant increase wear life of load bearing surfaces.

  8. Fatigue Life Methodology for Bonded Composite Skin/Stringer Configurations

    NASA Technical Reports Server (NTRS)

    Krueger, Ronald; Paris, Isabelle L.; OBrien, T. Kevin; Minguet, Pierre J.

    2001-01-01

    A methodology is presented for determining the fatigue life of composite structures based on fatigue characterization data and geometric nonlinear finite element (FE) analyses. To demonstrate the approach, predicted results were compared to fatigue tests performed on specimens which represented a tapered composite flange bonded onto a composite skin. In a first step, tension tests were performed to evaluate the debonding mechanisms between the flange and the skin. In a second step, a 2D FE model was developed to analyze the tests. To predict matrix cracking onset, the relationship between the tension load and the maximum principal stresses transverse to the fiber direction was determined through FE analysis. Transverse tension fatigue life data were used to -enerate an onset fatigue life P-N curve for matrix cracking. The resulting prediction was in good agreement with data from the fatigue tests. In a third step, a fracture mechanics approach based on FE analysis was used to determine the relationship between the tension load and the critical energy release rate. Mixed mode energy release rate fatigue life data were used to create a fatigue life onset G-N curve for delamination. The resulting prediction was in good agreement with data from the fatigue tests. Further, the prediction curve for cumulative life to failure was generated from the previous onset fatigue life curves. The results showed that the methodology offers a significant potential to Predict cumulative fatigue life of composite structures.

  9. Fracture toughness and fatigue life of MWCNT\\/epoxy composites

    Microsoft Academic Search

    N. Yu; Z. H. Zhang; S. Y. He

    2008-01-01

    The present work experimentally characterizes the mode-I fracture toughness and stress–life curve of multi-walled carbon nanotube-(MWCNT-)reinforced epoxy-matrix composites. The effects of carbon nanotube weight fraction and voids on the composite fracture toughness are studied. The average fracture toughness of 1wt%- and 3wt%-MWCNT\\/epoxy composites is 1.29 and 1.62 times of that of pure epoxy, respectively. The 0.5wt%-MWCNT\\/epoxy composites’ fatigue lives are

  10. Tension fatigue analysis and life prediction for composite laminates

    NASA Technical Reports Server (NTRS)

    O'Brien, T. K.; Rigamonti, M.; Zanotti, C.

    1989-01-01

    A methodology is presented for the tension fatigue analysis and life prediction of composite laminates subjected to tension fatigue loading. The methodology incorporates both the generic fracture mechanics characterization of delamination and the assessment of the infuence of damage on laminate fatigue life. Tension fatigue tests were conducted on quasi-isotropic and orthotropic glass epoxy, graphite epoxy, and glass/graphite epoxy hybrid laminates, demonstrating good agreement between measured and predicted lives.

  11. Fatigue Life Methodology for Bonded Composite Skin/Stringer Configurations

    NASA Technical Reports Server (NTRS)

    Krueger, Ronald; Paris, Isabelle L.; OBrien, T. Kevin

    2000-01-01

    A methodology is presented for determining the fatigue life of bonded composite skin/stringer structures based on delamination fatigue characterization data and geometric nonlinear finite element analyses. Results were compared to fatigue tests on stringer flange/skin specimens to verify the approach.

  12. Proposed framework for thermomechanical life modeling of metal matrix composites

    Microsoft Academic Search

    G. R. Halford; B. A. Lerch; J. F. Saltsman

    1993-01-01

    The framework of a mechanics of materials model is proposed for thermomechanical fatigue (TMF) life prediction of unidirectional, continuous-fiber metal matrix composites (MMC's). Axially loaded MMC test samples are analyzed as structural components whose fatigue lives are governed by local stress-strain conditions resulting from combined interactions of the matrix, interfacial layer, and fiber constituents. The metallic matrix is identified as

  13. Probabilistic fatigue life prediction of metallic and composite materials

    NASA Astrophysics Data System (ADS)

    Xiang, Yibing

    Fatigue is one of the most common failure modes for engineering structures, such as aircrafts, rotorcrafts and aviation transports. Both metallic materials and composite materials are widely used and affected by fatigue damage. Huge uncertainties arise from material properties, measurement noise, imperfect models, future anticipated loads and environmental conditions. These uncertainties are critical issues for accurate remaining useful life (RUL) prediction for engineering structures in service. Probabilistic fatigue prognosis considering various uncertainties is of great importance for structural safety. The objective of this study is to develop probabilistic fatigue life prediction models for metallic materials and composite materials. A fatigue model based on crack growth analysis and equivalent initial flaw size concept is proposed for metallic materials. Following this, the developed model is extended to include structural geometry effects (notch effect), environmental effects (corroded specimens) and manufacturing effects (shot peening effects). Due to the inhomogeneity and anisotropy, the fatigue model suitable for metallic materials cannot be directly applied to composite materials. A composite fatigue model life prediction is proposed based on a mixed-mode delamination growth model and a stiffness degradation law. After the development of deterministic fatigue models of metallic and composite materials, a general probabilistic life prediction methodology is developed. The proposed methodology combines an efficient Inverse First-Order Reliability Method (IFORM) for the uncertainty propogation in fatigue life prediction. An equivalent stresstransformation has been developed to enhance the computational efficiency under realistic random amplitude loading. A systematical reliability-based maintenance optimization framework is proposed for fatigue risk management and mitigation of engineering structures.

  14. Temperature distribution of thick thermoset composites

    NASA Astrophysics Data System (ADS)

    Guo, Zhan-Sheng; Du, Shanyi; Zhang, Boming

    2004-05-01

    The development of temperature distribution of thick polymeric matrix laminates during an autoclave vacuum bag process was measured and compared with numerically calculated results. The finite element formulation of the transient heat transfer problem was carried out for polymeric matrix composite materials from the heat transfer differential equations including internal heat generation produced by exothermic chemical reactions. Software based on the general finite element software package was developed for numerical simulation of the entire composite process. From the experimental and numerical results, it was found that the measured temperature profiles were in good agreement with the numerical ones, and conventional cure cycles recommended by prepreg manufacturers for thin laminates should be modified to prevent temperature overshoot.

  15. Fatigue Life Prediction of Pultruded E-glass\\/Polyurethane Composites

    Microsoft Academic Search

    Pizhong Qiao; Mijia Yang

    2006-01-01

    In this article, the tension–tension fatigue behavior of newly developed pultruded E-glass\\/polyurethane composites is characterized, and an improved model for fatigue life prediction including the effects of stress ratio, frequency, and mean stress as the testing parameters is proposed. The proposed non-dimensional analysis is in good agreement with the predictions of existing available fatigue data and present testing data. The

  16. A life prediction model for laminated composite structural components

    NASA Technical Reports Server (NTRS)

    Allen, David H.

    1990-01-01

    A life prediction methodology for laminated continuous fiber composites subjected to fatigue loading conditions was developed. A summary is presented of research completed. A phenomenological damage evolution law was formulated for matrix cracking which is independent of stacking sequence. Mechanistic and physical support was developed for the phenomenological evolution law proposed above. The damage evolution law proposed above was implemented to a finite element computer program. And preliminary predictions were obtained for a structural component undergoing fatigue loading induced damage.

  17. Dramatic increase in fatigue life in hierarchical graphene composites.

    PubMed

    Yavari, F; Rafiee, M A; Rafiee, J; Yu, Z-Z; Koratkar, N

    2010-10-01

    We report the synthesis and fatigue characterization of fiberglass/epoxy composites with various weight fractions of graphene platelets infiltrated into the epoxy resin as well as directly spray-coated on to the glass microfibers. Remarkably only ?0.2% (with respect to the epoxy resin weight and ?0.02% with respect to the entire laminate weight) of graphene additives enhanced the fatigue life of the composite in the flexural bending mode by up to 1200-fold. By contrast, under uniaxial tensile fatigue conditions, the graphene fillers resulted in ?3-5-fold increase in fatigue life. The fatigue life increase (in the flexural bending mode) with graphene additives was ?1-2 orders of magnitude superior to those obtained using carbon nanotubes. In situ ultrasound analysis of the nanocomposite during the cyclic fatigue test suggests that the graphene network toughens the fiberglass/epoxy-matrix interface and prevents the delamination/buckling of the glass microfibers under compressive stress. Such fatigue-resistant hierarchical materials show potential to improve the safety, reliability, and cost effectiveness of fiber-reinforced composites that are increasingly the material of choice in the aerospace, automotive, marine, sports, biomedical, and wind energy industries. PMID:20863061

  18. Progressive Failure And Life Prediction of Ceramic and Textile Composites

    NASA Technical Reports Server (NTRS)

    Xue, David Y.; Shi, Yucheng; Katikala, Madhu; Johnston, William M., Jr.; Card, Michael F.

    1998-01-01

    An engineering approach to predict the fatigue life and progressive failure of multilayered composite and textile laminates is presented. Analytical models which account for matrix cracking, statistical fiber failures and nonlinear stress-strain behavior have been developed for both composites and textiles. The analysis method is based on a combined micromechanics, fracture mechanics and failure statistics analysis. Experimentally derived empirical coefficients are used to account for the interface of fiber and matrix, fiber strength, and fiber-matrix stiffness reductions. Similar approaches were applied to textiles using Repeating Unit Cells. In composite fatigue analysis, Walker's equation is applied for matrix fatigue cracking and Heywood's formulation is used for fiber strength fatigue degradation. The analysis has been compared with experiment with good agreement. Comparisons were made with Graphite-Epoxy, C/SiC and Nicalon/CAS composite materials. For textile materials, comparisons were made with triaxial braided and plain weave materials under biaxial or uniaxial tension. Fatigue predictions were compared with test data obtained from plain weave C/SiC materials tested at AS&M. Computer codes were developed to perform the analysis. Composite Progressive Failure Analysis for Laminates is contained in the code CPFail. Micromechanics Analysis for Textile Composites is contained in the code MicroTex. Both codes were adapted to run as subroutines for the finite element code ABAQUS and CPFail-ABAQUS and MicroTex-ABAQUS. Graphic user interface (GUI) was developed to connect CPFail and MicroTex with ABAQUS.

  19. Computer Prediction and Experimental Determination of Fatigue Life Probability Distributions

    Microsoft Academic Search

    Hoda Abdel-Kader Elmaraghy

    1976-01-01

    One of the central unsolved problems of engineering design is prediction of the probability distribution of fatigue life of structural members and machine components. Fatigue data scatter is a manifestation of the probabilistic nature of fatigue failure. A relationship is known to exist between the distributions of the number of cycles-to-failure and the applied stress through the probabilistic stress-life (S-N)

  20. 12 CFR 2.3 - Distribution of credit life insurance income.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 false Distribution of credit life insurance income. 2.3 Section 2.3...DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.3 Distribution of credit life insurance income. (a) Distribution of...

  1. 12 CFR 2.3 - Distribution of credit life insurance income.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 false Distribution of credit life insurance income. 2.3 Section 2.3...DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.3 Distribution of credit life insurance income. (a) Distribution of...

  2. 12 CFR 2.3 - Distribution of credit life insurance income.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 false Distribution of credit life insurance income. 2.3 Section 2.3...DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.3 Distribution of credit life insurance income. (a) Distribution of...

  3. 12 CFR 2.3 - Distribution of credit life insurance income.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 false Distribution of credit life insurance income. 2.3 Section 2.3...DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.3 Distribution of credit life insurance income. (a) Distribution of...

  4. 12 CFR 2.3 - Distribution of credit life insurance income.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Distribution of credit life insurance income. 2.3 Section 2.3...DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.3 Distribution of credit life insurance income. (a) Distribution of...

  5. Generation of Finite Life Distributional Goodman Diagrams for Reliability Prediction

    NASA Technical Reports Server (NTRS)

    Kececioglu, D.; Guerrieri, W. N.

    1971-01-01

    The methodology of developing finite life distributional Goodman diagrams and surfaces is described for presenting allowable combinations of alternating stress and mean stress to the design engineer. The combined stress condition is that of an alternating bending stress and a constant shear stress. The finite life Goodman diagrams and surfaces are created from strength distributions developed at various ratios of alternating to mean stress at particular cycle life values. The conclusions indicate that the Von Mises-Hencky ellipse, for cycle life values above 1000 cycles, is an adequate model of the finite life Goodman diagram. In addition, suggestions are made which reduce the number of experimental data points required in a fatigue data acquisition program.

  6. Isothermal life prediction of composite lamina using a damage mechanics approach

    NASA Technical Reports Server (NTRS)

    Abuelfoutouh, Nader Mohamed; Verrilli, M. J.; Halford, G. R.

    1989-01-01

    A method for predicting isothermal plastic fatigue life of a composite lamina is presented in which both fibers and matrix are isotropic materials. In general, the fatigue resistances of the matrix, fibers, and interfacial material must be known in order to predict composite fatigue life. Composite fatigue life is predicted using only the matrix fatigue resistance due to inelasticity micromechanisms. The effect of the fiber orientation on loading direction is accounted for while predicting composite life. The application is currently limited to isothermal cases where the internal thermal stresses that might arise from thermal strain mismatch between fibers and matrix are negligible. The theory is formulated to predict the fatigue life of a composite lamina under either load or strain control. It is applied currently to predict the life of tungsten-copper composite lamina at 260 C under tension-tension load control. The calculated life of the lamina is in good agreement with available composite low cycle fatigue data.

  7. Composite-flywheel durability and life. Part I. Test program

    SciTech Connect

    Kulkarni, S.V.; Reifsnider, K.L.

    1982-09-01

    It has been demonstrated that flywheels made from composite materials are capable of storing energy at a significantly greater energy density than flywheels made from conventional metals. Composite flywheels which can store up to 80 Wh/kg have been successfully tested. In addition, composite flywheels are inherently safer for applications in vehicles and other devices since the failure of such wheels does not produce large pieces of heavy material that become dangerous projectiles, but generally produces a large number of pieces varying in size from chunks of delaminated laminates to dust and string- or straw-like matter. Composite flywheels are also thought to be more durable since composite materials generally perform very well under long-term and fatigue loading, frequently better than metals. However, the relatively limited experience that has been gained in using composite materials in high performance structures for long periods of time requires that special care be taken to verify the durability of any such design by experimental programs. An experimental program designed to establish the durability and life of the composite flywheel designs available at this time is presented. The objectives of the test program are as follows: to establish the durability and lifetime of flywheel rotors under conditions which include all of the essential details of the spectrum loading that rotors are likely to sustain as an energy storage device for various applications; to identify critical performance and durability characteristics which potentially limit the long term use of the rotor designs currently under development; and to develop test techniques and philosophies which can be used for fatigue testing of flywheels and to relate specimen data to rotor performance. Part I consists of the development of the test plan methodology.

  8. A self-healing polymer composite for extended fatigue life

    SciTech Connect

    Brown, E. N. (Eric N.); Jones, A. S. (Alan S.); White, S. R. (Scott R.); Sottos, Nancy R.

    2004-01-01

    A novel approach is explored for improving the fatigue life of thermosetting polymers through the addition of self-healing functionality. Thermosetting polymers are used in a wide variety of applications, but are susceptible to the initiation and propagation of small cracks deep within the structure where detection is difficult and repair is virtually impossible. The material under investigation is an epoxy matrix composite, which utilizes embedded microcapsules to store a healing agent and an embedded catalyst. A propagating crack exposes particles of catalyst and ruptures the microcapsules, which release healing agent into the crack plane. Polymerization of the healing agent is triggered by contact with the catalyst. Fatigue crack retardation and arrest from self-healing functionality result from crack-tip shielding mechanisms, such as hydrodynamic pressure and artificial-crack closure. In situ healing is observed to significantly extended fatigue life or permanently arrested fatigue crack growth over a wide range of loading conditions.

  9. Proposed framework for thermomechanical life modeling of metal matrix composites

    NASA Technical Reports Server (NTRS)

    Halford, Gary R.; Lerch, Bradley A.; Saltsman, James F.

    1993-01-01

    The framework of a mechanics of materials model is proposed for thermomechanical fatigue (TMF) life prediction of unidirectional, continuous-fiber metal matrix composites (MMC's). Axially loaded MMC test samples are analyzed as structural components whose fatigue lives are governed by local stress-strain conditions resulting from combined interactions of the matrix, interfacial layer, and fiber constituents. The metallic matrix is identified as the vehicle for tracking fatigue crack initiation and propagation. The proposed framework has three major elements. First, TMF flow and failure characteristics of in situ matrix material are approximated from tests of unreinforced matrix material, and matrix TMF life prediction equations are numerically calibrated. The macrocrack initiation fatigue life of the matrix material is divided into microcrack initiation and microcrack propagation phases. Second, the influencing factors created by the presence of fibers and interfaces are analyzed, characterized, and documented in equation form. Some of the influences act on the microcrack initiation portion of the matrix fatigue life, others on the microcrack propagation life, while some affect both. Influencing factors include coefficient of thermal expansion mismatch strains, residual (mean) stresses, multiaxial stress states, off-axis fibers, internal stress concentrations, multiple initiation sites, nonuniform fiber spacing, fiber debonding, interfacial layers and cracking, fractured fibers, fiber deflections of crack fronts, fiber bridging of matrix cracks, and internal oxidation along internal interfaces. Equations exist for some, but not all, of the currently identified influencing factors. The third element is the inclusion of overriding influences such as maximum tensile strain limits of brittle fibers that could cause local fractures and ensuing catastrophic failure of surrounding matrix material. Some experimental data exist for assessing the plausibility of the proposed framework.

  10. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifing Philosophy

    NASA Technical Reports Server (NTRS)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, Leigh

    2007-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle's Kevlar-49 fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed non-conservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic-plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23% lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  11. Life Modeling and Design Analysis for Ceramic Matrix Composite Materials

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The primary research efforts focused on characterizing and modeling static failure, environmental durability, and creep-rupture behavior of two classes of ceramic matrix composites (CMC), silicon carbide fibers in a silicon carbide matrix (SiC/SiC) and carbon fibers in a silicon carbide matrix (C/SiC). An engineering life prediction model (Probabilistic Residual Strength model) has been developed specifically for CMCs. The model uses residual strength as the damage metric for evaluating remaining life and is posed probabilistically in order to account for the stochastic nature of the material s response. In support of the modeling effort, extensive testing of C/SiC in partial pressures of oxygen has been performed. This includes creep testing, tensile testing, half life and residual tensile strength testing. C/SiC is proposed for airframe and propulsion applications in advanced reusable launch vehicles. Figures 1 and 2 illustrate the models predictive capabilities as well as the manner in which experimental tests are being selected in such a manner as to ensure sufficient data is available to aid in model validation.

  12. Maximum likelihood estimation for life distributions with competing failure modes

    NASA Technical Reports Server (NTRS)

    Sidik, S. M.

    1979-01-01

    Systems which are placed on test at time zero, function for a period and die at some random time were studied. Failure may be due to one of several causes or modes. The parameters of the life distribution may depend upon the levels of various stress variables the item is subject to. Maximum likelihood estimation methods are discussed. Specific methods are reported for the smallest extreme-value distributions of life. Monte-Carlo results indicate the methods to be promising. Under appropriate conditions, the location parameters are nearly unbiased, the scale parameter is slight biased, and the asymptotic covariances are rapidly approached.

  13. Creep-fatigue life prediction of in situ composite solders

    SciTech Connect

    Kuo, C.G.; Sastry, S.M.L.; Jerina, K.L. [Washington Univ., St. Louis, MO (United States)

    1995-12-01

    Eutectic tin-lead solder alloys subjected to cyclic loading at room temperature experience creep-fatigue interactions due to high homologous temperature. Intermetallic reinforcements of Ni{sub 3}Sn{sub 4} and Cu{sub 6}Sn{sub 5} are incorporated into eutectic tin-lead alloy by rapid solidification processes to form in situ composite solders. In this study, the in situ composite solders were subjected to combined creep and fatigue deformation at room temperature. Under cyclic deformation, the dominant damage mechanism of in situ composite solders is proposed to be growth of cavities. A constrained cavity growth model is applied to predict creep-fatigue life by taking into account the tensile loading component as well as the compressive loading component when reversed processes can occur. An algorithm to calculate cavity growth in each fatigue cycle is used to predict the number of fatigue cycles to failure, based on a critical cavity size of failure. Calculated lives are compared to experimental data under several fatigue histories, which include fully reversed stress-controlled fatigue, zero-tension stress-controlled fatigue, stress-controlled fatigue with tension hold time, fully reversed strain-controlled fatigue, and zero-tension strain-controlled fatigue. The model predicts the creep-fatigue lives within a factor of 2 with the incorporation of an appropriate compressive healing factor in most cases. Discrepancy between calculated lives and experimental results is discussed.

  14. The composition of the gut microbiota throughout life, with an emphasis on early life

    PubMed Central

    Rodríguez, Juan Miguel; Murphy, Kiera; Stanton, Catherine; Ross, R. Paul; Kober, Olivia I.; Juge, Nathalie; Avershina, Ekaterina; Rudi, Knut; Narbad, Arjan; Jenmalm, Maria C.; Marchesi, Julian R.; Collado, Maria Carmen

    2015-01-01

    The intestinal microbiota has become a relevant aspect of human health. Microbial colonization runs in parallel with immune system maturation and plays a role in intestinal physiology and regulation. Increasing evidence on early microbial contact suggest that human intestinal microbiota is seeded before birth. Maternal microbiota forms the first microbial inoculum, and from birth, the microbial diversity increases and converges toward an adult-like microbiota by the end of the first 3–5 years of life. Perinatal factors such as mode of delivery, diet, genetics, and intestinal mucin glycosylation all contribute to influence microbial colonization. Once established, the composition of the gut microbiota is relatively stable throughout adult life, but can be altered as a result of bacterial infections, antibiotic treatment, lifestyle, surgical, and a long-term change in diet. Shifts in this complex microbial system have been reported to increase the risk of disease. Therefore, an adequate establishment of microbiota and its maintenance throughout life would reduce the risk of disease in early and late life. This review discusses recent studies on the early colonization and factors influencing this process which impact on health. PMID:25651996

  15. Composite flywheel durability and life expectancy: test program

    SciTech Connect

    Kulkarni, S.V.; Reifsnider, K.L.; Boyd, D.M.

    1981-07-14

    The goals of this project are to: determine the durability and life expectancy of flywheel rotors; identify critical performance and durability characteristics that control the long-term service and safety of rotors and rotor containments; and develop test procedures that can be used to economically evaluate the performance of flywheels under cyclic loading in the laboratory and to relate that information to long-term service behavior. Approximately half the project is complete, including the following tasks: a material property data base has been assembled for each major material to be used in the flywheels; material property data has been characterized and modeled; the initial version of a generic test program has been designed; and some NDE characterization of all prototype composite flywheels rotors has been conducted.

  16. Bayesian estimation of life parameters in the Weibull distribution.

    NASA Technical Reports Server (NTRS)

    Canavos, G. C.; Tsokos, C. P.

    1973-01-01

    Development of a Bayesian analysis of the scale and shape parameters in the Weibull distribution and the corresponding reliability function with respect to the usual life-testing procedures. For the scale parameter theta, Bayesian estimates of theta and reliability are obtained for the uniform, exponential, and inverted gamma prior probability densities. Bhattacharya's results (1967) for the one-parameter exponential life-testing distribution are reduced to a special case of these results. A fully Bayesian analysis of both the scale and shape parameters is developed by assuming independent prior distributions; since in the latter case, analytical tractability is not possible, Bayesian estimates are obtained through a conjunction of Monte Carlo simulation and numerical-integration techniques. In both cases, a computer simulation is carried out, and a comparison is made between the Bayesian and the corresponding minimum-variance unbiased, or maximum likelihood, estimates. As expected, the Bayesian estimates are superior.

  17. Stress distribution in antifriction composite materials

    Microsoft Academic Search

    L. V. Zabolotnyi

    1979-01-01

    The optimum shape of hard inclusions in a composite material, irrespective of the magnitude of load and mode of its application to the surface, is a spheroid or ellipsoid of revolution. The characteristic linear size of a hard inclusion should be greater than the calculated diameter of a single spot of contact. If a composite material is to exhibit high

  18. Distributed multimedia service composition with statistical QoS assurances

    Microsoft Academic Search

    Xiaohui Gu; Klara Nahrstedt

    2006-01-01

    Service composition allows advanced distributed multimedia services to be automatically composed from atomic multimedia service components based on the user's dynamic service requirements. However, existing service com- position solutions lack user desired scalability, flexibility and multi-constrained quality-of-service (QoS) support. In this paper, we present a distributed multimedia service composition framework, called SpiderNet, to address the challenges. SpiderNet provides both statistical

  19. Fatigue Life Methodology for Tapered Hybrid Composite Flexbeams

    NASA Technical Reports Server (NTRS)

    urri, Gretchen B.; Schaff, Jeffery R.

    2006-01-01

    Nonlinear-tapered flexbeam specimens from a full-size composite helicopter rotor hub flexbeam were tested under combined constant axial tension and cyclic bending loads. Two different graphite/glass hybrid configurations tested under cyclic loading failed by delamination in the tapered region. A 2-D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. The analysis results from two geometrically nonlinear finite element codes, ANSYS and ABAQUS, are presented and compared. Strain energy release rates (G) associated with simulated delamination growth in the flexbeams are presented from both codes. These results compare well with each other and suggest that the initial delamination growth from the tip of the ply-drop toward the thick region of the flexbeam is strongly mode II. The peak calculated G values were used with material characterization data to calculate fatigue life curves for comparison with test data. A curve relating maximum surface strain to number of loading cycles at delamination onset compared well with the test results.

  20. Tension fatigue analysis and life prediction for composite laminates

    NASA Technical Reports Server (NTRS)

    Obrien, T. K.; Rigamonti, M.; Zanotti, C.

    1988-01-01

    A tension fatigue life prediction methodology for composite laminates is presented. Tension fatigue tests were conducted on quasi-isotropic and orthotropic glass epoxy, graphite epoxy, and glass/graphite epoxy hybrid laminates. Edge delamination onset data were used to generate plots of strain energy release rate as a function of cycles to delamination onset. These plots were then used along with strain energy release rate analyses of delaminations initiating at matrix cracks to predict local delamination onset. Stiffness loss was measured experimentally to account for the accumulation of matrix cracks and for delamination growth. Fatigue failure was predicted by comparing the increase in global strain resulting from stiffness loss to the decrease in laminate failure strain resulting from delaminations forming at matrix cracks through the laminate thickness. Good agreement between measured and predicted lives indicated that the through-thickness damage accumulation model can accurately describe fatigue failure for laminates where the delamination onset behavior in fatigue is well characterized, and stiffness loss can be monitored in real time to account for damage growth.

  1. Quantum logic unites compositional functional semantics and distributional semantic models

    E-print Network

    Paris-Sud XI, Université de

    Quantum logic unites compositional functional semantics and distributional semantic models Anne but to sentences, paragraphs etc. They are ruled by laws of logic inherent to language. Natural language conveys in by the familiar logical models, the intensional aspect by distributional semantic models, DSM's. We propose

  2. Prey nutrient composition has different effects on Pardosa wolf spiders with dissimilar life histories

    Microsoft Academic Search

    Kim Jensen; David Mayntz; Søren Toft; David Raubenheimer; Stephen J. Simpson

    2011-01-01

    The nutritional composition of prey is known to influence predator life histories, but how the life history strategies of\\u000a predators affect their susceptibility to nutrient imbalance is less investigated. We used two wolf spider species with different\\u000a life histories as model predators: Pardosa amentata, which have a fixed annual life cycle, and Pardosa prativaga, which reproduce later and can extend

  3. Barium distributions in teeth reveal early life dietary transitions in primates

    PubMed Central

    Austin, Christine; Smith, Tanya M.; Bradman, Asa; Hinde, Katie; Joannes-Boyau, Renaud; Bishop, David; Hare, Dominic J.; Doble, Philip; Eskenazi, Brenda; Arora, Manish

    2013-01-01

    Early life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations1,2. Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth3. Uncovering early life dietary history in fossils is hampered by the absence of prospectively-validated biomarkers that are not modified during fossilisation4. Here we show that major dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively-recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother’s milk and through the weaning process. We also document transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, suggesting an abrupt cessation of breastfeeding at 1.2 years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history. PMID:23698370

  4. Barium distributions in teeth reveal early-life dietary transitions in primates.

    PubMed

    Austin, Christine; Smith, Tanya M; Bradman, Asa; Hinde, Katie; Joannes-Boyau, Renaud; Bishop, David; Hare, Dominic J; Doble, Philip; Eskenazi, Brenda; Arora, Manish

    2013-06-13

    Early-life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations. Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth. Uncovering early-life dietary history in fossils is hampered by the absence of prospectively validated biomarkers that are not modified during fossilization. Here we show that large dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother's milk through the weaning process. We also document dietary transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, indicating an abrupt cessation of breastfeeding at 1.2?years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history. PMID:23698370

  5. Web Services Composition for Distributed Data Mining

    Microsoft Academic Search

    Ali Shaikh Ali; Omer F. Rana; Ian J. Taylor

    2005-01-01

    A Web services-based toolkit for supporting distributed data mining is presented. A workflow engine is provided within the toolkit to enable a user to compose Web services to implement particular point solutions. Three types of Web services are provided to implement data mining functions: (1) classifiers; (2) clustering algorithms; and (3) association rules. Additional capability is made available through GNUPlot

  6. An empirical Bayes approach for the Poisson life distribution.

    NASA Technical Reports Server (NTRS)

    Canavos, G. C.

    1973-01-01

    A smooth empirical Bayes estimator is derived for the intensity parameter (hazard rate) in the Poisson distribution as used in life testing. The reliability function is also estimated either by using the empirical Bayes estimate of the parameter, or by obtaining the expectation of the reliability function. The behavior of the empirical Bayes procedure is studied through Monte Carlo simulation in which estimates of mean-squared errors of the empirical Bayes estimators are compared with those of conventional estimators such as minimum variance unbiased or maximum likelihood. Results indicate a significant reduction in mean-squared error of the empirical Bayes estimators over the conventional variety.

  7. A distributed scheme for autonomous service composition

    Microsoft Academic Search

    Stephen Herborn; Yoann Lopez; Aruna Seneviratne

    2005-01-01

    Some multimedia content may be divisible into independently routable components, e.g. audio and video flows. As a result media content adaptation services may be linked in serial, parallel and hybrid configurations to form a directed, acyclic graph of composed services. We specify a distributed service path selection scheme for the construction of composed directed service graphs, which integrates a peer-to-peer

  8. A Framework for Event Composition in Distributed Systems

    Microsoft Academic Search

    Peter R. Pietzuch; Brian Shand; Jean Bacon

    2003-01-01

    For large-scale distributed applications such as internet-wide or ubiquitous systems, event-based communication is an eectiv e messag- ing mechanism between components. In order to handle the large volume of events in such systems, composite event detection enables application components to express interest in the occurrence of complex patterns of events. In this paper, we introduce a general composite event detection

  9. Effects of cyclic stress distribution models on fatigue life predictions

    NASA Astrophysics Data System (ADS)

    Sutherland, H. J.; Veers, P. S.

    1994-10-01

    The fatigue analysis of a wind turbine component typically uses representative samples of cyclic loads to determine lifetime loads. In this paper, several techniques currently in use are compared to one another based on fatigue life analyses. The generalized Weibull fitting technique is used to remove the artificial truncation of large-amplitude cycles that is inherent in relatively short data sets. Using data from the Sandia/DOE 34-m Test Bed, the generalized Weibull file technique is shown to be excellent for matching the body of the distribution of cyclic loads and for extrapolating the tail of the distribution. However, the data also illustrate that the fitting technique is not a substitute for an adequate data base.

  10. Composition distributions in Ge(Si)/Si(001) quantum dots.

    SciTech Connect

    Liao, Xiaozhou; Zou, J. (Jin); Cockayne, D. J. (David J.)

    2002-01-01

    Knowledge on the composition of hetero-epitaxial grown semiconductor quantum dots (QDs) is very important for revealing the growth mechanisms and the structure-property relationships of the QDs. However, composition determination in QDs is not an easy task because of the small QD sizes especially in the vertical dimension. In this study, two techniques - [001] zone axis bright-field diffraction contrast imaging combined with image simulations and electron energy filtering imaging (EFI) - were used to investigate the composition distributions of Ge(Si)/Si(001) QDs.

  11. Integration of distributed strain and temperature sensors in composite coiled tubing

    NASA Astrophysics Data System (ADS)

    Inaudi, Daniele; Glisic, Branko

    2006-03-01

    Composite coiled tubing is an emerging technology in the oil and gas sector that presents important advantages compared to the steel coiled tubing and conventional drilling. The composite tube has reduced weight, allowing extended reach and improved fatigue life. An additional advantage resides in the fact that the coiled tube wall can contain and protect additional functional elements, such as electrical conductors and fiber optics for sensing and data communication. Sensing systems based on Brillouin and Raman scattering can be used to verify the pipe operational parameters, prevent failure, optimize oil production from the well, provide strain distribution along the tubing and detect hot-spots in high-power cables. The integration of such sensing elements into composite tubing presents additional advantages and challenges. On one hand the embedded sensors are protected by the composite material and can be installed during production, avoiding external installation that could interfere with the tubing operations. In the other hand, the integration of optical fiber sensors into the composite structure requires the development of appropriate packaging and installation techniques that allow easy handling during production and avoid and damage to the sensor and the composite structure itself. This contribution presents the sensing cable designs for temperature and strain sensing in a composite coiled tubing as well as testing results form initial field demonstrations.

  12. 41 CFR 101-27.209 - Utilization and distribution of shelf-life items.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Utilization and distribution of shelf-life items. 101-27.209 Section 101-27...MANAGEMENT 27.2-Management of Shelf-Life Materials § 101-27.209 Utilization and distribution of shelf-life items. Where it is determined...

  13. 41 CFR 101-27.209 - Utilization and distribution of shelf-life items.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Utilization and distribution of shelf-life items. 101-27.209 Section 101-27...MANAGEMENT 27.2-Management of Shelf-Life Materials § 101-27.209 Utilization and distribution of shelf-life items. Where it is determined...

  14. 41 CFR 101-27.209 - Utilization and distribution of shelf-life items.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Utilization and distribution of shelf-life items. 101-27.209 Section 101-27...MANAGEMENT 27.2-Management of Shelf-Life Materials § 101-27.209 Utilization and distribution of shelf-life items. Where it is determined...

  15. 41 CFR 101-27.209 - Utilization and distribution of shelf-life items.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Utilization and distribution of shelf-life items. 101-27.209 Section 101-27...MANAGEMENT 27.2-Management of Shelf-Life Materials § 101-27.209 Utilization and distribution of shelf-life items. Where it is determined...

  16. 41 CFR 101-27.209 - Utilization and distribution of shelf-life items.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Utilization and distribution of shelf-life items. 101-27.209 Section 101-27...MANAGEMENT 27.2-Management of Shelf-Life Materials § 101-27.209 Utilization and distribution of shelf-life items. Where it is determined...

  17. Litter sex composition affects life-history traits in yellow-bellied marmots

    E-print Network

    Blumstein, Daniel T.

    Litter sex composition affects life-history traits in yellow-bellied marmots Raquel Monclu´ s1-bellied marmots (Marmota flaviventris) and documented the effects of weaned litter sex composition and anogenital-bellied marmots Introduction Litter sex ratio has important consequences for parental fit- ness because male

  18. A normalization method for life-time prediction of composite materials

    E-print Network

    Paris-Sud XI, Université de

    dimensional normalization tech- nique. The first part of the article details the materials and testsA normalization method for life-time prediction of composite materials M. Darwichea , G. Bousalehb is to predict the rupture of specimens of composite materials. During a creep experiment, with traction method

  19. Viscoelastically prestressed polymeric matrix composites – Potential for useful life and impact protection

    Microsoft Academic Search

    Kevin S. Fancey

    2010-01-01

    A viscoelastically prestressed polymeric matrix composite (VPPMC) is produced by applying tension to polymeric fibres, the tensile load being released prior to moulding the fibres into a matrix. Following matrix solidification, compressive stresses imparted by the viscoelastically strained fibres improve composite tensile, flexural and impact properties. This study focuses on the potential for useful life and impact protection capability by

  20. Natural Language Processing with Distributional Compositional Models Jean Maillard

    E-print Network

    Natural Language Processing with Distributional Compositional Models Jean Maillard Supervised by: Dr Stephen Clark, Computer Laboratory, University of Cambridge Natural Language Processing know a word by the company it keeps". The principle is that the meaning of a word can be captured

  1. NOAA Technical Report NMFS 79 July 1989 Species Composition, Distribution,

    E-print Network

    NOAA Technical Report NMFS 79 July 1989 Species Composition, Distribution, and Relative Abundance.S. Department of Commerce #12;NOAA TECHNICAL REPOIU NMFS The major responsibilities of the National Marine. It collects, analyzes, and publishes statistics on various phases of the industry. The NOAA Technical Report

  2. Composition and Size Distribution of Residential Wood Smoke Particles

    Microsoft Academic Search

    John A. Rau

    1989-01-01

    Residential wood combustion emissions are an important source of organic and elemental carbon particulate matter in many urban and suburban areas. This research determined the organic and elemental carbon composition and size distribution of particulate emissions for hot- and cool-burning wood stoves and from conventional fireplaces. Sampling was done from smoke plumes which had been cooled and diluted by ambient

  3. Composition distributions of particles in a gelling mixture.

    PubMed

    Lushnikov, A A

    2014-03-01

    Gelation in a two component disperse system wherein binary coagulation governs the temporal changes of particle composition spectra is studied for the crossproduct coagulation kernel proportional to m1n2+m2n1, with m,n being the numbers of monomers of the first and the second component in the coalescing pair of particles. This model reveals the sol-gel transition, i.e., after a finite interval of time the conservation of the total particle mass concentration violates because of the formation of giant particles (the gel). This paper reports on the exact solution of this model for arbitrary initial particle composition spectra. Exact expressions for the particle composition spectrum, the gel mass, and the second moments of the composition distribution are derived. Two scenarios of gelation, where the gel is either active or passive, are considered. PMID:24730804

  4. Composition distributions of particles in a gelling mixture

    NASA Astrophysics Data System (ADS)

    Lushnikov, A. A.

    2014-03-01

    Gelation in a two component disperse system wherein binary coagulation governs the temporal changes of particle composition spectra is studied for the crossproduct coagulation kernel proportional to m1n2+m2n1, with m ,n being the numbers of monomers of the first and the second component in the coalescing pair of particles. This model reveals the sol-gel transition, i.e., after a finite interval of time the conservation of the total particle mass concentration violates because of the formation of giant particles (the gel). This paper reports on the exact solution of this model for arbitrary initial particle composition spectra. Exact expressions for the particle composition spectrum, the gel mass, and the second moments of the composition distribution are derived. Two scenarios of gelation, where the gel is either active or passive, are considered.

  5. Impact Parameter Dependent Parton Distributions for a Composite Relativistic System

    E-print Network

    D. Chakrabarti; A. Mukherjee

    2005-01-14

    We investigate the impact parameter dependent parton distributions for a relativistic composite system in light-front framework. We take an effective two-body spin-1/2 state, namely an electron dressed with a photon in QED. We express the impact parameter dependent parton distributions in terms of overlaps of light-cone wave functions. We obtain the scale dependence of both fermion and gauge boson distributions and show the distortion of the pdfs in the transverse space for transverse polarization of the state at one loop level.

  6. Creep-fatigue life prediction of in situ composite solders

    Microsoft Academic Search

    C. G. Kuo; S. M. L. Sastry; K. L. Jerina

    1995-01-01

    Eutectic tin-lead solder alloys subjected to cyclic loading at room temperature experience creep-fatigue interactions due to high homologous temperature. Intermetallic reinforcements of Ni3Sn4 and Cu6Sn5 are incorporated into eutectic tin-lead alloy by rapid solidification processes to form in situ composite solders. In this study, the in situ composite solders were subjected to combined creep and fatigue deformation at room temperature.

  7. Creep-fatigue life prediction of in situ composite solders

    Microsoft Academic Search

    C. G. Kuo; S. M. L. Sastry; K. L. Jerina

    1995-01-01

    Eutectic tin-lead solder alloys subjected to cyclic loading at room temperature experience creep-fatigue interactions due\\u000a to high homologous temperature. Intermetallic reinforcements of Ni3Sn4 and Cu6Sn5 are incorporated into eutectic tin-lead alloy by rapid solidification processes to formin situ composite solders. In this study, thein situ composite solders were subjected to combined creep and fatigue deformation at room temperature. Under cyclic

  8. Carbon nanofiber polymer composites: evaluation of life cycle energy use.

    PubMed

    Khanna, Vikas; Bakshi, Bhavik R

    2009-03-15

    Holistic evaluation of emerging nanotechnologies using systems analysis is pivotal for guiding their safe and sustainable development. While toxicity studies of engineered nanomaterials are essential, understanding of the potential large scale impacts of nanotechnology is also critical for developing sustainable nanoproducts. This work evaluates the life cycle energetic impact associated with the production and use of carbon nanofiber (CNF) reinforced polymer nanocomposites (PNC). Specifically, both simple CNF and carbon nanofiber-glass fiber (CNF-GF) hybrid PNCs are evaluated and compared with steel for equal stiffness design. Life cycle inventory is developed based on published literature and best available engineering information. A cradle-to-gate comparison suggests that for equal stiffness design, CNF reinforced PNCs are 1.6-12 times more energy intensive than steel. It is anticipated that the product use phase may strongly influence whether any net savings in life cycle energy consumption can be realized. A case study involving the use of CNF and CNF-GF reinforced PNCs in the body panels of automobiles highlights that the use of PNCs with lower CNF loading ratios has the potential for net life cycle energy savings relative to steel owing to improved fuel economy benefits. Other factors such as cost, toxicity impact of CNF, and end-of-life issues specific to CNFs need to be considered to evaluate the final economic and environmental performance of CNF reinforced PNC materials. PMID:19368217

  9. Bounds on the Strength Distribution of Unidirectional Fiber Composites

    SciTech Connect

    Mahesh, S.; Beyerlein, I.J.; Phoenix, S.L.

    1999-06-13

    Failure mechanisms under tensile loading of unidirectional fiber composites comprising of Weibull fibers embedded in a matrix are studied using Monte-Carlo simulations. Two fundamental mechanisms of failure are recognized--stress concentration driven failure and strength driven failure. It is shown that the cumulative distribution function for composite strength predicted by the stressconcentration-driven failure and strength-driven failure form apparent upper and lower bounds respectively and also that failure mechanism switches from one to the other as fiber strength variability changes.

  10. Distributed photoacoustic system for cure monitoring of composites

    NASA Astrophysics Data System (ADS)

    Fomitchov, Pavel A.; Kim, Yeong K.; Kromine, Alexei K.; Krishnaswamy, Sridhar; Achenbach, Jan D.; Daniel, Isaac M.

    2001-07-01

    In this paper we describe a laser ultrasonic system for real-time monitoring of the degree of cure of a graphite-epoxy composite part during manufacturing. The system is integrated with a Resin-Transfer Molding (RTM) machine, and contains (i) a fiberized laser ultrasonic source, and (ii) an embedded ultrasonic sensor based on an intrinsic fiber optic Sagnac interferometer. Bulk ultrasonic waves generated by the laser source are transmitted into the composite structure and are subsequently detected by the embedded ultrasonic sensor. The degree of cure can be obtained from measurements of ultrasonic velocity and attenuation in the composite part. The use of an optical switch in the fiber optic delivery system of the laser ultrasonic source allows ultrasonic generation at several locations of the composite part. In this paper we discuss the design of the laser ultrasonic source and the sensor optimized for cure monitoring applications, and their integration with the RTM mold. The results of ultrasonic measurements during manufacturing of a composite specimen are presented. Our results show that laser ultrasonics offer distinct advantages for manufacturing of modern composite structures including the ability to operate in a high temperature and high pressure environment and provide distributed sensing that can cover critical areas of a component.

  11. A self-healing polymer composite for extended fatigue life

    Microsoft Academic Search

    E. N. Brown; A. S. Jones; S. R. White; Nancy R. Sottos

    2004-01-01

    A novel approach is explored for improving the fatigue life of thermosetting polymers through the addition of self-healing functionality. Thermosetting polymers are used in a wide variety of applications, but are susceptible to the initiation and propagation of small cracks deep within the structure where detection is difficult and repair is virtually impossible. The material under investigation is an epoxy

  12. Distribution of early life history stages of fishes in selected pools of the upper Mississippi River

    USGS Publications Warehouse

    Holland, L.E.

    1986-01-01

    Effective management of the fishery resources of the Upper Mississippi River and successful mitigation of the loss of critical habitat depend in part on an understanding of the reproductive and early life history requirements of the affected fishes. However, little is known about the use of nursery areas by fishes in the river. Of the nearly 130 species identified in the adult ichthyofauna, only a few are represented proportionally in the available data on early life stages because study designs have not included consideration of the early stages, collection gears have not adequately sampled the young, and eggs and larvae of some species are difficult to sample by conventional approaches. For the species collected, information is available on seasonal variations in total densities, composition, and catch among different habitat types. However, the data are most accurate for species with buoyant early life stages, such as freshwater drum (Aplodinotus grunniens) and gizzard shad (Dorosoma cepedianum). Eggs and larvae of freshwater drum dominate collections made in the main channel, whereas other larval fishes are usually most abundant in backwater habitats. The species found there usually deposit eggs on the substrate or on vegetation. Habitat preferences (as indicated by relative abundance) often shift as development proceeds and physical and behavioral changes occur in the larvae. Only limited information is available on the distribution of larvae within habitats, but it is clear that variations within habitats are significant.

  13. Impact Parameter Dependent Parton Distributions for a Relativistic Composite System

    E-print Network

    D. Chakrabarti; A. Mukherjee

    2004-10-08

    We investigate the impact parameter dependent parton distributions for a relativistic composite system in light-front framework. We express them in terms of overlaps of light-cone wave functions for a self consistent two-body spin-1/2 state, namely an electron dressed with a photon in QED. The pdfs are distorted in the transverse space for transverse polarization of the state at one loop level.

  14. Gangliosides in Rat Kidney: Composition, Distribution, and Developmental Changes

    Microsoft Academic Search

    Megumi Saito; Kiyoshi Sugiyama

    2001-01-01

    Gangliosides in rat kidney were analyzed for their composition, regional distribution, and developmental changes. Renal tissue from 7-week-old rats showed a GM3-dominant pattern with GD3 and several minor ganglioside components including GM4, GM2, GD1a, and an unknown ganglioside (ganglioside X). The tissue also contained c-series gangliosides that included GT3 as the main component with GT2 in a lesser amount. Ganglioside

  15. Characteristics of fatigue life and damage accumulation of short fiber-reinforced polymer composites

    SciTech Connect

    Yokobori, A.T. Jr. [Tohoku Univ., Sendai (Japan). Dept. of Mechatronics and Precision Engineering; Takeda, Hidetoshi [Idemitsu Petrochemical Co., Chiba (Japan); Adachi, Takeshi; Ha, J.C. [Ishinomaki Senshu Univ., Miyagi (Japan); Yokobori, Takeo [Teikyo Univ., Utsunomiya City, Tochigi (Japan). School of Science and Engineering

    1996-12-31

    The relation between fatigue life and damage accumulation of fiber-reinforced polymer composite (FRP) is not yet clarified. For practical use of FRP, it is necessary to relate the fatigue life to the mechanism of damage accumulation. Damage formation is controlled by the mechanical behavior of the interface between the matrix and fiber. The authors used short glass fiber-reinforced polycarbonate composite in the experiments. By using an in situ (real time) observational fatigue testing machine, they investigated the relationship between fatigue life and damage accumulation. From these results, the fatigue life of this material was found to be dominated by damage accumulation which results from microfracture at the interface between the matrix and fiber. This microfracture is controlled by a cycle-dependent mechanism.

  16. Age distribution curve in psychiatric admissions inversely correlates with Life Satisfaction.

    PubMed

    Le Bon, Olivier; Le Bon, Serge-Daniel

    2014-09-30

    A strong inverse correlation was found between the age-distribution curve of psychiatric admissions and the U-bend Life Satisfaction curve. It may indicate that the peak of mental disorders at midlife reflects a less satisfactory period of life or, conversely, that the mental health load burdens of Life Satisfaction. PMID:24908542

  17. Temperature dependence of stress–fatigue life data of FRP composites

    Microsoft Academic Search

    H. Mivehchi; A. Varvani-Farahani

    2011-01-01

    Polymer-matrix composites are viscoelastic materials, and their mechanical properties are significantly influenced by temperature.\\u000a The present study develops a power-law stress–fatigue life relation which takes into account the effect of temperature on\\u000a the fatigue strength of fibre-reinforced polymer (FRP) composites. The validity of the relation is evaluated on the basis\\u000a of various sets of experimental data found in the literature,

  18. Erratum to: Temperature dependence of stress–fatigue life data of FRP composites

    Microsoft Academic Search

    H. Mivehchi; A. Varvani-Farahani

    2011-01-01

    Polymer-matrix composites are viscoelastic materials, and their mechanical properties are significantly influenced by temperature.\\u000a The present study develops a power-law stress–fatigue life relation which takes into account the effect of temperature on\\u000a the fatigue strength of fibre-reinforced polymer (FRP) composites. The validity of the relation is evaluated on the basis\\u000a of various sets of experimental data found in the literature,

  19. On Testing Statistics of Harmonic New Better Than Renewal Used in Expectation Class of Life Distributions

    Microsoft Academic Search

    Gamal R. Elkahlout

    The harmonic new better or worse than renewal used in expectation classes of life distributions are considered in this paper. Relations of these classes with other existing classes of life distributions are explored and their closure properties under some reliability operations are studied. Test statistics of exponentiality for these classes are established under random censoring. Percentiles and the power estimates

  20. Two methods for determining pressure distribution in composite reservoirs

    SciTech Connect

    Hedayati, S.

    1988-01-01

    This study investigates two simplified numerical models for evaluating the transient pressure distribution in composite reservoirs. Comparisons are made between the results obtained for these two models and the general numerical solution which describes pressure in the two-member composite model. Partial differential equations for the General Composite model are developed from the continuity equation, the equation of state, and Darcy's law. Pressure solutions are obtained using Laplace transformation and the numerical inversion known as Stehfest's algorithm. These solutions are presented for wells in finite or infinite reservoirs. Solutions are also provided for both constant flow and constant pressure inner-boundary conditions. The effective radius and skin factor concepts are used to develop the first model. In the second model the inner zone is replaced by a layer of a different size, while retraining reservoir properties of the outer zone. The size of this new zone depends on the hydraulic diffusivities of both zones. The two models are evaluated for constant flow and constant pressure inner boundary conditions. Comparisons are made between the two models and the General Composite model for varying reservoir parameters. The analysis showed that for the constant flow case, both equivalent models gave more accurate results than for the constant pressure case. Both models predicted the pressure of the General Composite model with skin factors between +3 and {minus}2 with good accuracy. The precision of each model was improved with increasing dimensionless time; it was also improved with decreasing absolute value of the skin factor. The models compared favorably with the General Composite model for smaller radii but were slightly less accurate for larger radii of investigation.

  1. A Component-based Programming Model for Composite, Distributed Applications

    NASA Technical Reports Server (NTRS)

    Eidson, Thomas M.; Bushnell, Dennis M. (Technical Monitor)

    2001-01-01

    The nature of scientific programming is evolving to larger, composite applications that are composed of smaller element applications. These composite applications are more frequently being targeted for distributed, heterogeneous networks of computers. They are most likely programmed by a group of developers. Software component technology and computational frameworks are being proposed and developed to meet the programming requirements of these new applications. Historically, programming systems have had a hard time being accepted by the scientific programming community. In this paper, a programming model is outlined that attempts to organize the software component concepts and fundamental programming entities into programming abstractions that will be better understood by the application developers. The programming model is designed to support computational frameworks that manage many of the tedious programming details, but also that allow sufficient programmer control to design an accurate, high-performance application.

  2. Influence of Material Distribution on Impact Resistance of Hybrid Composites

    NASA Technical Reports Server (NTRS)

    Abatan, Ayu; Hu, Hurang

    1998-01-01

    Impact events occur in a wide variety of circumstances. A typical example is a bullet impacting a target made of composite material. These impact events produce time-varying loads on a structure that can result in damage. As a first step to understanding the damage resistance issue in composite laminates, an accurate prediction of the transient response during an impact event is necessary. The analysis of dynamic loadings on laminated composite plates has undergone considerable development recently. Rayleigh-Ritz energy method was used to determine the impact response of laminated plates. The impact response of composite plates using shear deformation plate theory was analyzed. In recent work a closed-form solution was obtained for a rectangular plate with four edges simply supported subjected to a center impact load using classical plate theory. The problem was further investigated and the analysis results compared of both classical plate theory and shear deformation theory, and found that classical plate theory predicts very accurate results for the range of small deformations considered. In this study, the influence of cross sectional material distribution on the comparative impact responses of hybrid metal laminates subjected to low and medium velocity impacts is investigated. A simple linear model to evaluate the magnitude of the impact load is proposed first, and it establishes a relation between the impact velocity and the impact force. Then a closed-form solution for impact problem is presented. The results were compared with the finite element analysis results. For an 11 layer-hybrid laminate, the impact response as a function of material distribution in cross-section is presented. With equal areal weight, the effect of the number of laminate layers on the impact resistance is also investigated. Finally, the significance of the presented results is discussed.

  3. Effect of Severe Undernutrition in Early Life on Growth, Brain Size and Composition in Adult Rats

    Microsoft Academic Search

    HELEN A. GUTHRIE; MYRTLE L. BROWN

    2010-01-01

    A study was undertaken to determine the effect of varying periods of undernutrition in postnatal life on the size and chemical composition of the brain in rehabilitated adult animals. Four groups of male albino rats were drawn from litters of 16 pups nursed by an undernourished dam. One group was weaned at 3 weeks to a diet of 18% casein.

  4. Physical Activity, Body Composition, and Perceived Quality of Life of Adults with Visual Impairments

    ERIC Educational Resources Information Center

    Holbrook, Elizabeth A.; Caputo, Jennifer L.; Perry, Tara L.; Fuller, Dana K.; Morgan, Don W.

    2009-01-01

    Relatively little is known about the health and fitness of adults with visual impairments. This article documents the physical activity levels and body-composition profiles of young and middle-aged adults with visual impairments and addresses the concomitant effects of these factors on perceived quality of life. (Contains 2 tables.)

  5. Three-axis distributed fiber optic strain measurement in 3D woven composite structures

    NASA Astrophysics Data System (ADS)

    Castellucci, Matt; Klute, Sandra; Lally, Evan M.; Froggatt, Mark E.; Lowry, David

    2013-03-01

    Recent advancements in composite materials technologies have broken further from traditional designs and require advanced instrumentation and analysis capabilities. Success or failure is highly dependent on design analysis and manufacturing processes. By monitoring smart structures throughout manufacturing and service life, residual and operational stresses can be assessed and structural integrity maintained. Composite smart structures can be manufactured by integrating fiber optic sensors into existing composite materials processes such as ply layup, filament winding and three-dimensional weaving. In this work optical fiber was integrated into 3D woven composite parts at a commercial woven products manufacturing facility. The fiber was then used to monitor the structures during a VARTM manufacturing process, and subsequent static and dynamic testing. Low cost telecommunications-grade optical fiber acts as the sensor using a high resolution commercial Optical Frequency Domain Reflectometer (OFDR) system providing distributed strain measurement at spatial resolutions as low as 2mm. Strain measurements using the optical fiber sensors are correlated to resistive strain gage measurements during static structural loading.

  6. Testing and Life Prediction for Composite Rotor Hub Flexbeams

    NASA Technical Reports Server (NTRS)

    Murri, Gretchen B.

    2004-01-01

    A summary of several studies of delamination in tapered composite laminates with internal ply-drops is presented. Initial studies used 2D FE models to calculate interlaminar stresses at the ply-ending locations in linear tapered laminates under tension loading. Strain energy release rates for delamination in these laminates indicated that delamination would likely start at the juncture of the tapered and thin regions and grow unstably in both directions. Tests of glass/epoxy and graphite/epoxy linear tapered laminates under axial tension delaminated as predicted. Nonlinear tapered specimens were cut from a full-size helicopter rotor hub and were tested under combined constant axial tension and cyclic transverse bending loading to simulate the loading experienced by a rotorhub flexbeam in flight. For all the tested specimens, delamination began at the tip of the outermost dropped ply group and grew first toward the tapered region. A 2D FE model was created that duplicated the test flexbeam layup, geometry, and loading. Surface strains calculated by the model agreed very closely with the measured surface strains in the specimens. The delamination patterns observed in the tests were simulated in the model by releasing pairs of MPCs along those interfaces. Strain energy release rates associated with the delamination growth were calculated for several configurations and using two different FE analysis codes. Calculations from the codes agreed very closely. The strain energy release rate results were used with material characterization data to predict fatigue delamination onset lives for nonlinear tapered flexbeams with two different ply-dropping schemes. The predicted curves agreed well with the test data for each case studied.

  7. Unequal geographic distribution of life expectancy in Seoul.

    PubMed

    Kim, Sangmi; Yi, Seonju; Kim, Meekyung; Kim, Bokyung; Lee, Hwayoung; Jeon, Taekryeon; Cho, Youngtae

    2015-03-01

    This study examined life expectancies in 25 gus, administrative districts of Seoul, the capital of Korea, by gender in 1995, 2002, and 2008 to explore trends in mortality inequality among areas. The authors constructed single-decrement life tables and employed between-group variance, the Theil index, and mean log deviation to measure absolute and relative disparities in life expectancy among areas during the periods 1995-2002 and 2002-2008. It was found that life expectancy gaps between gus have widened in absolute and relative terms in both genders over the decade, and that this pattern was particularly dramatic in females after 2002. This increasing gap could be attributable to the more negative health impact on females since the late 1990s stemming from the economic crisis, eventually reflected in their places of residence. Thus, a social buffer system to narrow the health gap between geographic areas and social classes must be established. PMID:22535557

  8. Bayesian Inference and Life Testing Plan for the Weibull Distribution in Presence of

    E-print Network

    Kundu, Debasis

    Bayesian Inference and Life Testing Plan for the Weibull Distribution in Presence of Progressive of the progressively censored Weibull distribution. It is well known that for a Weibull distribution, while computing to observe the behavior of the proposed methods, and a data analysis is conducted for illustrative purposes

  9. Accelerated life-tests for intermittent destructive inspection, with logistic failure-distribution

    Microsoft Academic Search

    So Young Sohn

    1997-01-01

    Statistically-optimal accelerated life-test plans are suggested for items whose lifetime follows a logistic distribution. Both the scale and location parameters of the lifetime distribution are functions of the stress level. The test plans accommodate intermittent destructive sampling. The number of sampled items which fail to pass the test at the time of each inspection follows a hypergeometric distribution; the number

  10. Accelerated Life Testing Model for a Generalized Birnbaum-Saunders Distribution

    E-print Network

    Boyer, Edmond

    Accelerated Life Testing Model for a Generalized Birnbaum-Saunders Distribution Yao Cheng and E. A modeled by Birnbaum-Saunders (B-S) and Weibull distributions. Sometimes, materials with high cycle fatigue of this paper is to investigate a general Birnbaum-Saunders (GB-S) distribution which covers diverse hazard

  11. Trends in the diversity, distribution and life history strategy of Arctic Hydrozoa (Cnidaria).

    PubMed

    Ronowicz, Marta; Kukli?ski, Piotr; Mapstone, Gillian M

    2015-01-01

    This is the first attempt to compile a comprehensive and updated species list for Hydrozoa in the Arctic, encompassing both hydroid and medusa stages and including Siphonophorae. We address the hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic by Hydrozoa after the Last Glacial Maximum. Presence-absence data of Hydrozoa in the Arctic were prepared on the basis of historical and present-day literature. The Arctic was divided into ecoregions. Species were grouped into distributional categories according to their worldwide occurrences. Each species was classified according to life history strategy. The similarity of species composition among regions was calculated with the Bray-Curtis index. Average and variation in taxonomic distinctness were used to measure diversity at the taxonomic level. A total of 268 species were recorded. Arctic-boreal species were the most common and dominated each studied region. Nineteen percent of species were restricted to the Arctic. There was a predominance of benthic species over holo- and meroplanktonic species. Arctic, Arctic-Boreal and Boreal species were mostly benthic, while widely distributed species more frequently possessed a pelagic stage. Our results support hypothesis that the presence of a pelagic stage (holo- or meroplanktonic) was not necessary to successfully recolonize the Arctic. The predominance of benthic Hydrozoa suggests that the Arctic could have been colonised after the Last Glacial Maximum by hydroids rafting on floating substrata or recolonising from glacial refugia. PMID:25793294

  12. Life cycle strain monitoring of composite airframe structures by FBG sensors

    NASA Astrophysics Data System (ADS)

    Takahashi, I.; Sekine, K.; Kume, M.; Takeya, H.; Minakuchi, S.; Takeda, N.; Enomoto, K.

    2013-04-01

    Life cycle health monitoring technology for composite airframe structures based on strain mapping is proposed. It detects damages and deformation harmful to the structures by strain mapping using fiber Bragg grating (FBG) sensors through their life cycles including the stages of molding, machining, assembling, operation, and maintenance. In this paper, we firstly carried out a strain monitoring test of CFRP mock-up structure through the life cycle including the stage of molding, machining, assembling, and operation. The experimental result confirms that the strain which arises in each life cycle stage can be measured by FBG sensors embedded in molding stage and demonstrates the feasibility of life cycle structural health monitoring by using FBG sensors. Secondly, we conducted the strain monitoring test of CFRP scarf-repaired specimen subject to fatigue load. FBG sensors were embedded in the scarf-repaired part of the specimen and their reflection spectra were measured in uni-axial cyclic load test. Strain changes were compared with the pulse thermographic inspection. As a result, strain measured by FBG sensors changed sensitively with debonded area of repair patch, which demonstrates that the debondings of repair patches in scarf-repaired composites due to fatigue load can be detected by FBG sensors.

  13. Distributional ecology and behaviour of the early life stages of the box-jellyfish Chironex fleckeri

    Microsoft Academic Search

    R. F. Hartwick

    1991-01-01

    Laboratory observations on reared life stages of Chironex fleckeri (Cubozoa: Chirodropidae) have been combined with field sampling and observations to outline the life cycle of the species and the spatial and temporal distribution of populations in Queensland, Australia. A seasonal alternation of polypoid and medusoid generations from winter to summer respectively is accompanied by a shift in preferred habitat from

  14. A Neural Network Degradation Model for Computing and Updating Residual Life Distributions

    Microsoft Academic Search

    Nagi Z. Gebraeel; Mark A. Lawley

    2008-01-01

    The ability to accurately estimate the residual life of partially degraded components is arguably the most challenging problem in prognostic condition monitoring. This paper focuses on the development of a neural network-based degradation model that utilizes condition-based sensory signals to compute and continuously update residual life distributions of partially degraded components. Initial predicted failure times are estimated through trained neural

  15. Morphology, size distribution and elemental composition of several dental debris

    NASA Astrophysics Data System (ADS)

    Abe, Shigeaki; Iwadera, Nobuki; Esaki, Mitsue; Aoyama, Ken-Ichi; Akasaka, Tsukasa; Uo, Motohiro; Morita, Manabu; Yawaka, Yasutaka; Watari, Fumio

    2012-12-01

    We investigated morphologies, size distributions and elemental compositions of dental debris formed by cutting/grinding teeth or dental alloys. The average size of debris formed by cutting/grinding dental alloy was around 100 ?m and that of teeth was 20 ?m. The debris formed by grinding with diamond or carborundum point had isotropic irregular shape, while the debris formed by cutting with carbide bar had characteristic lathe-cut shape. The elemental analysis indicated that the debris formed by grinding dental alloy with carborundum point consisted of not only the particles of the alloy but also the particles of Si compounds with the size of around 10 ?m. The particles of Si compounds would be formed by abrasion of the grinding instrument (carborundum, SiC). Similarly, the debris formed by grinding with diamond point also contained submicro-sized particles consisting of C compounds. The results indicate that the morphology and composition of dental debris are varied depending on the combination between the workpiece and the cutting/grinding materials and that the dental debris consist of both the workpiece and the cutting/grinding materials in some combination. In addition, some of the debris of tooth had the size less than 2 ?m, which has a potential to induce inflammation. Though the inflammation can be expected at low level, it is required to investigate the details in future.

  16. Influence of Weight Gain Rate on Early Life Nutritional Status and Body Composition of Children

    PubMed Central

    Magalhães, Taís Cristina Araújo; Ribeiro, Andréia Queiroz; Priore, Silvia Eloiza; Franceschini, Sylvia do Carmo Castro; Sant'Ana, Luciana Ferreira da Rocha

    2014-01-01

    Objective. To evaluate the influence of the weight gain rate at 4–6 months on nutritional status and body composition in children between 4 and 7 years of age. Methods. Retrospective cohort study, sample of 257 children. Data collection was performed in two stages, with the first relating to retrospective data of weight gain from birth to the first 4–6 months of life in the patient records. Measurements of weight, height, waist circumference, and body composition in children between ages 4 and 7 years were obtained. Nutritional status was assessed by the BMI/age. Control variables, such as pregnancy, breastfeeding, lifestyle, and sociodemographics, were studied. Descriptive analysis and multiple linear regression were performed. Results. In the nutritional status assessment, the prevalence of overweight observed was 24.9%. After adjusting for control variables, it was found that the increase of the WGR at 4–6 months of age explained the occurrence of higher BMI/age, percentage of total body fat, body fat percentage in the android region, and waist circumference in children between 4 and 7 years of age. Conclusion. The increase of the WGR in the first months of life can lead to the occurrence of higher values of parameters of nutritional status and body composition in later life. PMID:25538953

  17. Microstructural Influence on Deformation and Fatigue Life of Composites Using the Generalized Method of Cells

    NASA Technical Reports Server (NTRS)

    Arnold, S. M.; Murthy, P.; Bednarcyk, B. A.; Pineda, E. J.

    2015-01-01

    A fully coupled deformation and damage approach to modeling the response of composite materials and composite laminates is presented. It is based on the semi-­-analytical generalized method of cells (GMC) micromechanics model as well as its higher fidelity counterpart, HFGMC, both of which provide closed-form constitutive equations for composite materials as well as the micro scale stress and strain fields in the composite phases. The provided constitutive equations allow GMC and HFGMC to function within a higher scale structural analysis (e.g., finite element analysis or lamination theory) to represent a composite material point, while the availability of the micro fields allow the incorporation of lower scale sub­-models to represent local phenomena in the fiber and matrix. Further, GMC's formulation performs averaging when applying certain governing equations such that some degree of microscale field accuracy is surrendered in favor of extreme computational efficiency, rendering the method quite attractive as the centerpiece in a integrated computational material engineering (ICME) structural analysis; whereas HFGMC retains this microscale field accuracy, but at the price of significantly slower computational speed. Herein, the sensitivity of deformation and the fatigue life of graphite/epoxy PMC composites, with both ordered and disordered microstructures, has been investigated using this coupled deformation and damage micromechanics based approach. The local effects of fiber breakage and fatigue damage are included as sub-models that operate on the microscale for the individual composite phases. For analysis of laminates, classical lamination theory is employed as the global or structural scale model, while GMC/HFGMC is embedded to operate on the microscale to simulate the behavior of the composite material within each laminate layer. A key outcome of this study is the statistical influence of microstructure and micromechanics idealization (GMC or HFGMC) on the overall accuracy of unidirectional and laminated composite deformation and fatigue response.

  18. Concrete Sentence Spaces for Compositional Distributional Models of Meaning

    E-print Network

    Grefenstette, Edward; Clark, Stephen; Coecke, Bob; Pulman, Stephen

    2011-01-01

    Coecke, Sadrzadeh, and Clark (arXiv:1003.4394v1 [cs.CL]) developed a compositional model of meaning for distributional semantics, in which each word in a sentence has a meaning vector and the distributional meaning of the sentence is a function of the tensor products of the word vectors. Abstractly speaking, this function is the morphism corresponding to the grammatical structure of the sentence in the category of finite dimensional vector spaces. In this paper, we provide a concrete method for implementing this linear meaning map, by constructing a corpus-based vector space for the type of sentence. Our construction method is based on structured vector spaces whereby meaning vectors of all sentences, regardless of their grammatical structure, live in the same vector space. Our proposed sentence space is the tensor product of two noun spaces, in which the basis vectors are pairs of words each augmented with a grammatical role. This enables us to compare meanings of sentences by simply taking the inner product...

  19. Asteroid taxonomy and the distribution of the compositional types

    NASA Technical Reports Server (NTRS)

    Zellner, B.

    1979-01-01

    Physical observations of minor planets documented in the TRIAD computer file are used to classify 752 objects into the broad compositional types C, S, M, E, R, and U (unclassifiable) according to the prescriptions adopted by Bowell et al. (1978). Diameters are computed from the photometric magnitude using radiometric and/or polarimetric data where available, or else from albedos characteristic of the indicated type. An analysis of the observational selection effects leads to tabulation of the actual number of asteroids, as a function of type and diameter, in each of 15 orbital element zones. For the whole main belt the population is 75% of type C, 15% of type S, and 10% of other types, with no belt-wide dependence of the mixing ratios on diameter. In some zones the logarithmic diameter-frequency relations are decidedly nonlinear. The relative frequency of S-type objects decreases smoothly outward through the main belt, with exponential scale length 0.5 AU. The rarer types show a more chaotic, but generally flatter, distribution over distance. Characteristic type distributions, contrasting with the background population, are found for the Eos, Koronis, Nysa and Themis families.

  20. Environmental Factors Related to the Distribution, Abundance, and Life History Characteristics of Mountain Whitefish in Idaho

    Microsoft Academic Search

    Kevin A. Meyer; F. Steven Elle; James A. Lamansky Jr

    2009-01-01

    Mountain whitefish Prosopium williamsoni are a broadly distributed native salmonid in western North America, but comparatively little investigation has been made regarding their population characteristics. We surveyed 2,043 study sites to assess whether physiochemical stream conditions affected mountain whitefish distribution and abundance in southern Idaho, and at 20 of these sites life history characteristics were also estimated. A total of

  1. Effects of breed type and feeding regimen on goat composition, retail shelf-life, sensory and chemical characteristics 

    E-print Network

    Oman, Jessica Spurling

    1995-01-01

    EFFECTS OF BREED TYPE AND FEEDING REGIMEN ON GOAT COMPOSITION, RETAIL SHELF-LIFE, SENSORY AND CHEMICAL CHARACTERISTICS A Thesis by JESSICA SPURLING OMAN Submitted to the Office of Graduate Studies of Texas A&M University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1995 Major Subject: Animal Science EFFECTS OF BREED TYPE AND FEEDING REGIMEN ON GOAT COMPOSITION, RETAIL SHELF-LIFE, SENSORY AND CHEMICAL CHARACTERISTICS A Thesis by JESSICA...

  2. Bridging porous Si-C composites with conducting agents for improving battery cycle life

    NASA Astrophysics Data System (ADS)

    Li, Zhenzhen; Wang, Wei; Li, Zhihu; Qin, Zhihong; Wang, Jun; Liu, Zhaoping

    2015-07-01

    Porous silicon-carbon (Si-C) composites have been considered to be one of the most effective architectures to improve the cycle life of Si based anode because of its native ability to accommodate the large volume change during discharge/charge process. It is found that lots of reported porous Si-C electrodes employed large amount of binder materials to enhance the structural stability which significantly decreased gravimetric capacity of the whole electrode with limited active materials. In this work, without loss of active materials, various conducting agents were used to build electrical bridges between porous Si-C composites, which significantly improved the structural stability and hence the cycle life. Due to the increase of connection possibilities, cycle life of zero-dimensional MCMB bridged electrode reaches 80 cycles with a capacity retention of 80%, and it can be further promoted to 200 cycles for the VGCF bridged electrode and 220 cycles for the rGO bridged electrode. This work paves an effective route to construct stable Si electrode with porous structures as building blocks without the decrease of active materials.

  3. Litter sex composition affects life-history traits in yellow-bellied marmots.

    PubMed

    Monclús, Raquel; Blumstein, Daniel T

    2012-01-01

    1. The presence of siblings might have long-lasting fitness consequences because they influence the early environment in which an animal develops. Several studies under laboratory conditions have shown long-lasting consequences from the presence of male siblings in utero on morphology and life-history traits. However, in wild animals, such effects of litter sex composition are unexplored. 2. We capitalized on a long-term study of individually marked yellow-bellied marmots (Marmota flaviventris) and documented the effects of weaned litter sex composition and anogenital distance on several life-history and fitness traits. 3. First, we demonstrated that the number of males in a litter influenced anogenital distance. Then, we found that masculinized females, those with larger anogenital distances, were less likely to survive their first hibernation, were more likely to disperse and were less likely to become pregnant and wean young. Males from male-biased litters had lower growth rates, but we failed to detect longer-term consequences. 4. Taken together, our results show profound sex-dependent effects of litter sex composition, probably due to differential prenatal exposure to androgens, in free-living animals. We conclude that masculinization might constitute an alternative mechanism explaining variation in different demographic traits. This finding highlights the importance of studying these maternal effects, and they enhance our concern over the widespread use of endocrine disrupting compounds. PMID:21801175

  4. Agent-based semantic composition of Web services using distributed description logics

    E-print Network

    Paris-Sud XI, Université de

    Agent-based semantic composition of Web services using distributed description logics Mourad Ouziri Distributed Description Logics (DDL) to achieve the semantic composition of web services. DDL allows one to make semantic connections between ontologies and thus web services, as well as to reason to get

  5. The impact of detailed urbanscale processing on the composition, distribution, and radiative forcing of anthropogenic aerosols

    E-print Network

    The impact of detailed urbanscale processing on the composition, distribution, and radiative is considered. Citation: Cohen, J. B., R. G. Prinn, and C. Wang (2011), The impact of detailed urbanscale processing on the composition, distribution, and radiative forcing of anthropogenic aerosols, Geophys. Res

  6. Behavioural early-life exposures and body composition at age 15 years

    PubMed Central

    Leary, S D; Lawlor, D A; Davey Smith, G; Brion, M J; Ness, A R

    2015-01-01

    Background/Objectives: Previous studies have demonstrated associations between some early-life exposures and later obesity, but most have used body mass index in childhood or adulthood as the outcome. The objective of this study was to investigate whether early-life exposures were associated with directly measured fat and lean mass in adolescence. Subjects/Methods: This study used data on 4750 mother–offspring pairs, collected as a part of the Avon Longitudinal Study of Parents and Children, Bristol, UK between 1991 and 1992; associations between behavioural exposures occurring from conception up to 5 years of age (maternal and paternal smoking during pregnancy, breastfeeding, age at introduction to solids, dietary patterns and physical inactivity during early childhood) and offspring body composition measured by dual-energy X-ray absorptiometry at ~15 years were assessed. Results: After full adjustment for potential confounders, maternal smoking during pregnancy, having a junk food diet and spending more time watching television in early childhood were all associated with higher fat mass at age 15, whereas maternal smoking, having a healthy diet and playing computer games more frequently in early childhood were all associated with a higher lean mass at age 15. Associations with paternal smoking were generally weaker for both fat and lean mass, but as there was no strong statistical evidence for maternal vs paternal differences, confounding by social factors rather than a direct effect of maternal smoking cannot be ruled out. Early feeding was not associated with fat or lean mass at age 15. Conclusions: This study does not provide compelling evidence for associations between most early-life factors and body composition in adolescence. However, possible associations with dietary patterns and physical inactivity in early childhood require further investigation in other cohorts that have direct measurements of adolescent body composition. PMID:25664839

  7. Evaluation of hole quality and bit life in graphite epoxy composites using video scanning 

    E-print Network

    Lednicky, Thomas Edward

    1985-01-01

    five holes were measured by video scanning Figure 9 shows a photograph of an acceptable hole drill- ed by a dagger bit. On the same page is Figure 10 which is a thresholded computer image of the same hole. This computer image is strickly black...EVALUATION OF HOLE QUALITY AND BIT LIFE IN GRAPHITE EPOXY COMPOSITES USING VIDEO SCANNING A Thesis by THOMAS EDWARD LEDNICKY Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirements for the degree...

  8. Modeling and life prediction methodology for Titanium Matrix Composites subjected to mission profiles

    NASA Technical Reports Server (NTRS)

    Mirdamadi, M.; Johnson, W. S.

    1994-01-01

    Titanium matrix composites (TMC) are being evaluated as structural materials for elevated temperature applications in future generation hypersonic vehicles. In such applications, TMC components are subjected to complex thermomechanical loading profiles at various elevated temperatures. Therefore, thermomechanical fatigue (TMF) testing, using a simulated mission profile, is essential for evaluation and development of life prediction methodologies. The objective of the research presented in this paper was to evaluate the TMF response of the (0/90)2s SCS-6/Timetal-21S subjected to a generic hypersonic flight profile and its portions with a temperature ranging from -130 C to 816 C. It was found that the composite modulus, prior to rapid degradation, had consistent values for all the profiles tested. A micromechanics based analysis was used to predict the stress-strain response of the laminate and of the constituents in each ply during thermomechanical loading conditions by using only constituent properties as input. The fiber was modeled as elastic with transverse orthotropic and temperature dependent properties. The matrix was modeled using a thermoviscoplastic constitutive relation. In the analysis, the composite modulus degradation was assumed to result from matrix cracking and was modeled by reducing the matrix modulus. Fatigue lives of the composite subjected to the complex generic hypersonic flight profile were well correlated using the predicted stress in 0 degree fibers.

  9. Modeling and life prediction methodology for titanium matrix composites subjected to mission profiles

    SciTech Connect

    Mirdamadi, M. [Analytical Services and Materials Inc., Hampton, VA (United States); Johnson, W.S. [Georgia Inst. of Tech., Atlanta, GA (United States). School of Materials Science and Engineering

    1996-12-31

    Titanium matrix composites (TMCs) are being evaluated as structural materials for elevated temperature applications in future generation hypersonic vehicles. In such applications, TMC components are subjected to complex thermomechanical loading profiles at various elevated temperatures. Therefore, thermomechanical fatigue (TMF) testing, using a simulated mission profile, is essential for evaluation and development of life prediction methodologies. The objective of the research presented in this paper was to evaluate the TMF response of the [0/90]{sub 2s} SCS-6/TIMETAL-21S subjected to a generic hypersonic flight profile and its portions with a temperature ranging from {minus}130 to 816 C. It was found that the composite modulus, prior to rapid degradation, had consistent values for all the profiles tested. The accumulated minimum strain was also found to be the same for all the profiles tested. A micromechanics-based analysis was used to predict the stress-strain response of the laminate and of the constituents in each ply during thermomechanical loading conditions by using only constituent properties as input. The fiber was modeled as elastic with transverse orthotropic and temperature-dependent properties. The matrix was modeled using a thermoviscoplastic constitutive relationship. In the analysis, the composite modulus degradation was assumed to result from matrix cracking and was modeled by reducing the matrix modulus. Fatigue lives of the composite subjected to the complex generic hypersonic flight profiles were well correlated using the predicted stress in 0{degree} fibers.

  10. Modeling and life prediction methodology for Titanium Matrix Composites subjected to mission profiles

    SciTech Connect

    Mirdamadi, M.; Johnson, W.S.

    1994-08-01

    Titanium matrix composites (TMC) are being evaluated as structural materials for elevated temperature applications in future generation hypersonic vehicles. In such applications, TMC components are subjected to complex thermomechanical loading profiles at various elevated temperatures. Therefore, thermomechanical fatigue (TMF) testing, using a simulated mission profile, is essential for evaluation and development of life prediction methodologies. The objective of the research presented in this paper was to evaluate the TMF response of the (0/90)2s SCS-6/Timetal-21S subjected to a generic hypersonic flight profile and its portions with a temperature ranging from -130 C to 816 C. It was found that the composite modulus, prior to rapid degradation, had consistent values for all the profiles tested. A micromechanics based analysis was used to predict the stress-strain response of the laminate and of the constituents in each ply during thermomechanical loading conditions by using only constituent properties as input. The fiber was modeled as elastic with transverse orthotropic and temperature dependent properties. The matrix was modeled using a thermoviscoplastic constitutive relation. In the analysis, the composite modulus degradation was assumed to result from matrix cracking and was modeled by reducing the matrix modulus. Fatigue lives of the composite subjected to the complex generic hypersonic flight profile were well correlated using the predicted stress in 0 degree fibers.

  11. Biogenic aerosols from Amazonia: Composition, size distributions and optical properties

    NASA Astrophysics Data System (ADS)

    Rizzo, L. V.; Artaxo, P. P.; Brito, J. F.; Barbosa, H. M.; Andreae, M. O.; Martin, S. T.

    2013-12-01

    Amazonia is an excellent laboratory to study atmospheric processes that are characteristic of natural conditions, as they existed prior to the impact of industrialization on the regional and global atmosphere. Biogenic aerosols dominate the particle population in Amazonia, showing a strong link between forest biology and atmospheric composition. In the fine fraction, aerosols are mostly secondary organic particles formed from biogenic emissions of trace gases, with a contribution of primary particles. In the coarse mode, primary biogenic particles dominates the picture. Aerosols have been continuously measured at the TT34 LBA tower at the ZF2 ecological station about 55 Km North of Manaus since January 2008. Fine mode aerosol mass concentration is very low in Amazonia, with PM2.5 of about 1.3×0.7 ?g m-3 and 3.4×2.0 ?g m-3 in the wet and dry seasons, respectively. In terms of particle number concentrations a median value of 220 cm-3 in the wet season and 2,200 cm-3 in the dry season were observed. An aerosol chemical speciation monitor (ACSM) was deployed in 2013, and it shows that organic aerosol account to 81% to the non-refractory PM1 aerosol loading at TT34, while in the dry season, a high 93% content of organic particles was observed. Size distribution shows the occurrence of bursts of particles with about 20 nanometers at night time, possibly associated with biological process. Very few events of new particle formation are observed. Aerosol light scattering and absorption coefficients at the TT34 site were low during the wet season, increasing by a factor of 5, approximately, in the dry season due to long range transport of biomass burning aerosols reaching the forest site. Aerosol single scattering albedo (SSA) ranged from 0.84 in the wet season up to 0.91 in the dry, indicating a surprising high absorption in the wet season, associated with biogenic particles.

  12. Effect of carbide distribution on rolling-element fatigue life of AMS 5749

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Bamberger, E. N.

    1983-01-01

    Endurance tests with ball bearings made of corrosion resistant bearing steel which resulted in fatigue lives much lower than were predicted are discussed. Metallurgical analysis revealed an undesirable carbide distribution in the races. It was shown in accelerated fatigue tests in the RC rig that large, banded carbides can reduce rolling element fatigue life by a factor of approximately four. The early spalling failures on the bearing raceways are attributed to the large carbide size and banded distribution.

  13. Distributed optical-fiber-based damage detection in composites

    Microsoft Academic Search

    Ian P. Giles; Michael Mondanos; Rodney A. Badcock; Peter A. Lloyd

    1999-01-01

    Composite materials are vulnerable to damage, and this can result in conservatism in design and increased maintenance costs. One way of reducing these costs is by integrating a system into the composite material which can sense the damage condition and provide an assessment of its size, location and significance. This is a difficult task, and one of the main challenges

  14. Three Semantics for Distributed Systems and their Relations with Alignment Composition

    E-print Network

    Paris-Sud XI, Université de

    Three Semantics for Distributed Systems and their Relations with Alignment Composition Antoine. A system composed of ontologies and align- ments interconnecting them is here in called a distributed system. We give three different semantics of a distributed system, that do not inter- fere

  15. A composite weighted multi-objective optimal approach for emergency logistics distribution

    Microsoft Academic Search

    Ming Liu; Lindu Zhao

    2007-01-01

    Improving the efficiency of distribution in emergency logistics research, which would decrease disaster damage in the other side. A new composite weighted multi- objective optimal approach for distributing commodities was constructed in this paper, which feature in including penalty function in objective functions, as well as time and cost during the transshipment in urgent relief distribution centers were considered in

  16. The galactic habitable zone and the age distribution of complex life in the Milky Way.

    PubMed

    Lineweaver, Charles H; Fenner, Yeshe; Gibson, Brad K

    2004-01-01

    We modeled the evolution of the Milky Way Galaxy to trace the distribution in space and time of four prerequisites for complex life: the presence of a host star, enough heavy elements to form terrestrial planets, sufficient time for biological evolution, and an environment free of life-extinguishing supernovae. We identified the Galactic habitable zone (GHZ) as an annular region between 7 and 9 kiloparsecs from the Galactic center that widens with time and is composed of stars that formed between 8 and 4 billion years ago. This GHZ yields an age distribution for the complex life that may inhabit our Galaxy. We found that 75% of the stars in the GHZ are older than the Sun. PMID:14704421

  17. Corona Characteristics of Distribution Line in Contact with Conductive Material and Life Estimation of Conductor Insulation

    Microsoft Academic Search

    Takahiko Yamashita; Tomoyuki Fujishima; Hiroyuki Kuba

    2010-01-01

    In relation to the accidents due to bird nests in contact with overhead distribution lines, the authors investigated on life estimation of conductor insulation. The accident is often caused by crow or magpie. There is a region in which magpie is being specified to the protected bird in Japan. In that region, the nest in the breeding season can not

  18. Disparate distribution patterns between canopy and subcanopy life-forms in two temperate North American forests

    Microsoft Academic Search

    R. D. Rheinhardt

    1992-01-01

    Quantitative vegetational data of canopy and woody subcanopy species (two life-forms adapted to occupy different strata at maturity) were compared with data collected in two temperate forest ecosystems to determine whether they exhibit a similar pattern of distribution. Tidal freshwater swamps (21 stands) and southern Appalachian forests (19 stands) were examined from data obtained using identical sampling methods. Separate structural

  19. Using Artificial Life Techniques for Distributed Grid Job Azin Moallem and Simone A. Ludwig

    E-print Network

    Ludwig, Simone

    the state of the system at each point in time. On the other hand, having all the load balancing information is a challenge which load balanc- ing algorithms address. Current load balancing implemen- tations for the Grid distributed artificial life-inspired load balancing algo- rithms using Ant Colony Optimization and Particle

  20. Temperature Effects on Gametophyte Life-History Traits and Geographic Distribution of Two Cryptic Kelp Species

    PubMed Central

    Oppliger, L. Valeria; Correa, Juan A.; Engelen, Aschwin H.; Tellier, Florence; Vieira, Vasco; Faugeron, Sylvain; Valero, Myriam; Gomez, Gonzalo; Destombe, Christophe

    2012-01-01

    A major determinant of the geographic distribution of a species is expected to be its physiological response to changing abiotic variables over its range. The range of a species often corresponds to the geographic extent of temperature regimes the organism can physiologically tolerate. Many species have very distinct life history stages that may exhibit different responses to environmental factors. In this study we emphasized the critical role of the haploid microscopic stage (gametophyte) of the life cycle to explain the difference of edge distribution of two related kelp species. Lessonia nigrescens was recently identified as two cryptic species occurring in parapatry along the Chilean coast: one located north and the other south of a biogeographic boundary at latitude 29–30°S. Six life history traits from microscopic stages were identified and estimated under five treatments of temperature in eight locations distributed along the Chilean coast in order to (1) estimate the role of temperature in the present distribution of the two cryptic L. nigrescens species, (2) compare marginal populations to central populations of the two cryptic species. In addition, we created a periodic matrix model to estimate the population growth rate (?) at the five temperature treatments. Differential tolerance to temperature was demonstrated between the two species, with the gametophytes of the Northern species being more tolerant to higher temperatures than gametophytes from the south. Second, the two species exhibited different life history strategies with a shorter haploid phase in the Northern species contrasted with considerable vegetative growth in the Southern species haploid stage. These results provide strong ecological evidence for the differentiation process of the two cryptic species and show local adaptation of the life cycle at the range limits of the distribution. Ecological and evolutionary implications of these findings are discussed. PMID:22723987

  1. Apollo 15 green glass - Compositional distribution and petrogenesis

    NASA Technical Reports Server (NTRS)

    Steele, Alison M.; Colson, Russell O.; Korotev, Randy L.; Haskin, Larry A.

    1992-01-01

    We have characterized a comprehensive suite of individual green-glass beads from Apollo 15 soil to determine interelement behavior and to constrain petrogenetic relationships. We analyzed 365 particles for trace elements by instrumental neutron activation analysis and analyzed 52 of them, selected to cover the compositional ranges observed for trace elements, for major elements by electron microprobe analysis. We confirm the observation of Delano (1979) that the beads comprise discrete compositional groups, although two of the groups he defined are further split on the basis of trace-element compositions. Each of the resulting seven groups has distinct average rare-earth abundances. The coherence between major- and trace-element data was masked in previous studies by imprecision, correlated error, and nonrepresentative sampling of the different groups. Most of the compositional characteristics of the green glasses can be explained by a model for batch equilibrium melting of a nearly homogeneous, ultramafic source region, when the complicating effects of high pressure and low oxygen fugacity are taken into account. The previously puzzling behavior of Ni and Co as apparently incompatible elements may arise from partial reduction of those elements to the zero oxidation state, resulting in low mineral/melt partition coefficients. The model also offers explanations for why the green glasses form boomerang-shaped trends on many two-element variation diagrams and why certain compositions (Groups A and D) are more abundant than glasses with other compositions.

  2. Moment distributions around holes in symmetric composite laminates subjected to bending moments

    NASA Technical Reports Server (NTRS)

    Prasad, C. B.; Shuart, M. J.

    1989-01-01

    An analytical investigation of the effects of holes on the moment distribution of symmetric composite laminates subjected to bending moments is described. A general, closed-form solution for the moment distribution of an infinite anisotropic plate is derived, and this solution is used to determine stress distributions both on the hole boundary and throughout the plate. Results are presented for several composite laminates that have holes and are subjected to either pure bending or cylindrical bending. Laminates with a circular hole or with an elliptical hole are studied. Laminate moment distributions are discussed, and ply stresses are described.

  3. Chemical composition and size distributions of coastal aerosols observed on the US East Coast

    Microsoft Academic Search

    Lili Xia; Yuan Gao

    2010-01-01

    Characterization of coastal aerosols is important to the study of the atmospheric input of nutrients to the adjacent marine and the ocean ecosystems. Over a land–ocean transition zone, however, aerosol composition could be strongly modified by anthropogenic emissions and transport processes. This work focuses on examining aerosol properties, in particular chemical composition, particle-size distributions and iron (Fe) solubility, over the

  4. Distributed optical-fiber-based damage detection in composites

    NASA Astrophysics Data System (ADS)

    Giles, Ian P.; Mondanos, Michael; Badcock, Rodney A.; Lloyd, Peter A.

    1999-05-01

    Composite materials are vulnerable to damage, and this can result in conservatism in design and increased maintenance costs. One way of reducing these costs is by integrating a system into the composite material which can sense the damage condition and provide an assessment of its size, location and significance. This is a difficult task, and one of the main challenges is to develop sensor systems that can detect damage reliably while not compromising the material properties of the composite or significantly increasing its weight. A sensor system will be described which fulfills some of these requirements. It is based on the use of a highly birefringent optical fiber. The whole length of the fiber is used as the sensor, which minimizes additional weight. It also enables information to be obtained on the position of the damage along its length. The mechanical properties of the composite material are not degraded when the fiber is embedded, as long as some simple precautions are taken. The sensor utilizes the propagation of low coherence polarized light in highly birefringent optical fiber. Light is launched into one of the polarization states of the fiber and is coupled into the orthogonal state in the presence of damage. The sensor is interrogated interferometrically. Its operation will be described in detail and results will be presented which illustrate its perforce in detecting impact induced damage in a number of different composite material systems. Benefits of the system will be described together with areas which need further development.

  5. Primary igneous rocks on Mars: Composition and distribution

    NASA Technical Reports Server (NTRS)

    Singer, Robert B.; Mcsween, Harry Y., Jr.

    1991-01-01

    The present knowledge of the crustal composition of Mars is synthesized and implications discussed for in-situ resource utilization. Sources of information include remote sensing observations, Viking XRF chemical measurements, and characteristics of the SNC meteorites (which most researchers now believe originated on Mars). There are a number of lines of evidence that abundant ferrous-iron rich igneous crustal rocks (and derivative soils) are available at or very near the current Martian surface at many locations on the planet. Most of these exposures show spectroscopic evidence for abundant pyroxene, consistent with basaltic compositions. The SNC meteorites, which have basaltic compositions, were also studied extensively. Interpretations of Mars crustal chemistry and mineralogy (petrology) based on these various sources are reviewed, and their consistencies and differences are discussed.

  6. A counter-reductionist argument for the influence of solute composition on ostracode distribution: Implications for paleoecology

    SciTech Connect

    Taylor, L.C.; Howard, K.W.F. (Univ. of Toronto, Ontario (Canada))

    1992-01-01

    The utility of fossil ostracodes for tracking climatically-driven Holocene physicochemical changes of lakes has been a recurrent theme in paleoenvironmental research. Recent studies, aimed at improving the precision of ostracode-mediated environmental reconstructions, have attempted to decipher this robust, ostracode-climate, couplet, and strong correlational evidence concerning the influence of solute composition on ostracode distribution has emerged. By drawing on two examples, namely the response of ostracodes to (1) Holocene hydrocompositional changes in a lake from Russell, Manitoba, and (2) the anthropogenic contamination of groundwater along an urban-rural transect in south-central Ontario, a hypothesis is generated to explain this apparent association. Contrary to the reductionist opinions (i.e. that hydrochemistry operates on ostracode distribution through the direct imposition of physiological barriers), solute composition is viewed as a surrogate variable through which to evaluate cumulative, immeasurable effects of climate, geology, hydrology and the biosphere (including humans). By virtue of their short life-cycles, it is suggested that ostracodes would overcome evolutionary barriers imposed by gradual changes in solute composition if it uniquely controlled their occurrence. Solving this problem would enhance the resolving power of paleoenvironmental reconstructions and, if the proposed argument is valid, it may lend credibility to uniformitarian principles operative in Quaternary paleoecology. The replacement of one group of species by another better adapted to an environment in its totality, seems more likely to hold up in ecological time, than adaptation to a single, specific, overriding hydrochemical parameter.

  7. Elemental composition and size distribution of particulates in Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    King, R. B.; Fordyce, J. S.; Neustadter, H. E.; Leibecki, H. F.

    1975-01-01

    Measurements were made of the elemental particle size distribution at five contrasting urban environments with different source-type distributions in Cleveland, Ohio. Air quality conditions ranged from normal to air pollution alert levels. A parallel network of high-volume cascade impactors (5-state) were used for simultaneous sampling on glass fiber surfaces for mass determinations and on Whatman-41 surfaces for elemental analysis by neutron activation for 25 elements. The elemental data are assessed in terms of distribution functions and interrelationships and are compared between locations as a function of resultant wind direction in an attempt to relate the findings to sources.

  8. Scaling effects on damage development, strength, and stress-rupture life laminated composites in tension

    NASA Astrophysics Data System (ADS)

    Lavoie, J. Andre

    The damage development and strength of ply-level scaled carbon/epoxy composite laminates having stacking sequence of ({+}thetasb{n}/{-}thetasb{n}/90sb{2n} rbracksb{s} where constraint ply angle, theta, was 0sp°, 15sp°, 30sp°,\\ 45sp°,\\ 60sp°, and 75sp°, and size was scaled as n = 1, 2, 3, and 4, is reported in Part I. X-radiography was used to monitor damage developments. First-ply failure stress, and tensile strength were recorded. First-ply failure of the midplane 90sp° plies depended on the stiffness of constraint plies, and size. All 24 cases were predicted using Zhang's shear-lag model and data generated from lbrack0sb2/90sb2rbracksb{s} cross-ply tests. Laminate strength was controlled by the initiation of a triangular-shaped local delamination of the surface angle plies. This delamination was predicted using O'Brien's strain energy release rate model for delamination of surface angle plies. For each ply angle, the smallest laminate was used to predict delamination (and strength) of the other sizes. The in-situ tensile strength of the 0sp° plies within different cross-ply, and quasi-isotropic laminates of varying size and stacking sequence is reported in Part II. No size effect was observed in the strength of 0sp° plies for those lay-ups having failure confined to the gauge section. Laminates exhibiting a size-strength relationship, had grip region failures for the larger sizes. A statistically significant set of 3-point bend tests of unidirectional beams were used to provide parameters for a Weibull model, to re-examine relationship between ultimate strength of 0sp° plies and specimen volume. The maximum stress in the 0sp° plies in bending, and the tensile strength of the 0sp° plies (from valid tests only) was the same. Weibull theory predicted loss of strength which was not observed in the experiments. An effort to model the durability and life of quasi-isotropic E-glass/913 epoxy composite laminates under steady load and in an acidic environment is reported in Part III. Stress-rupture tests of unidirectional coupons immersed in a weak hydrochloric acid solution was conducted to determine their stress-life response. Creep tests were conducted on unidirectional coupons parallel and transverse to the fibers, and on {±}45sp° layups to characterize the lamina stress- and time-dependent compliances. These data were used in a composite stress-rupture life model, based on the critical element modeling philosophy of Reifsnider, to predict the life of two ply-level thickness-scaled quasi-isotropic laminates.

  9. Fatigue Life Prediction of Carbon Fiber-Reinforced Ceramic-Matrix Composites at Room and Elevated Temperatures. Part II: Experimental Comparisons

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2015-05-01

    This paper follows on from the earlier study (Part I) which investigated the fatigue behavior of unidirectional, cross-ply and 2.5D C/SiC composites at room and elevated temperatures. In this paper, a micromechanics approach to predict the fatigue life S-N curves of fiber-reinforced CMCs has been developed considering the fatigue damage mechanism of interface wear or interface oxidation. Upon first loading to fatigue peak stress, matrix multicracking and fiber/matrix interface debonding occur. The two-parameter Weibull model is used to describe fibers strength distribution. The stress carried by broken and intact fibres on the matrix crack plane under fatigue loading is determined based on the Global Load Sharing (GLS) criterion. The fibres failure probabilities under fatigue loading considering the degradation of interface shear stress and fibres strength have been obtained. When the broken fibres fraction approaches critical value, the composite would fatigue fail. The fatigue life S-N curves of unidirectional, cross-ply and 2.5D C/SiC composites at room and elevated temperatures have been predicted. The predicted results agreed with experimental data.

  10. Space Station environmental control and life support system distribution and loop closure studies

    NASA Technical Reports Server (NTRS)

    Humphries, William R.; Reuter, James L.; Schunk, Richard G.

    1986-01-01

    The NASA Space Station's environmental control and life support system (ECLSS) encompasses functional elements concerned with temperature and humidity control, atmosphere control and supply, atmosphere revitalization, fire detection and suppression, water recovery and management, waste management, and EVA support. Attention is presently given to functional and physical module distributions of the ECLSS among these elements, with a view to resource requirements and safety implications. A strategy of physical distribution coupled with functional centralization is for the air revitalization and water reclamation systems. Also discussed is the degree of loop closure desirable in the initial operational capability status Space Station's oxygen and water reclamation loops.

  11. Setting Stress Distribution in Particle Reinforced Polymer Composites

    Microsoft Academic Search

    A. M. Boriek; J. E. Akin; C. D. Armeniades

    1988-01-01

    The effect of the geometric arrangement of spherical aggregates in a highly filled polymer composite (such as polymer concrete) on the setting stresses, due to resin shrink age during cure was investigated using three-dimensional finite element analysis. Simple cubic and face-centered cubic arrangements of perfect spherical aggregate were con sidered as well as a hexagonal-close-packed arrangement of hexagonal, prism-shaped aggregate.

  12. Aerobic training during hemodialysis improves body composition, muscle function, physical performance, and quality of life in chronic kidney disease patients

    PubMed Central

    Bae, Young-Hyeon; Lee, Suk Min; Jo, Jong Il

    2015-01-01

    [Purpose] We assessed the influences of individualized aerobic training on body composition, knee joint muscle function, physical performance, and quality of life in chronic kidney disease patients. [Subjects] Ten chronic kidney disease patients undergoing dialysis. [Methods] Overall physical function and quality of life before and after 12 weeks of aerobic training were evaluated by body composition, the six-minute walk test, cardiopulmonary exercise tests, and Short Form 36-item questionnaire. [Results] The six-minute walk test distance increased significantly after 12 weeks aerobic training. Resting metabolic rate, lactate threshold, maximum oxygen uptake, and quality of life tended to increase after training. Post-training weight, muscle mass, body fat mass, fat percentage, body mass index, and peak torque of right and left knee extension and flexion did not change significantly. [Conclusion] Intra-dialytic training can a safe approach to maintain or improve physical performance and quality of life of chronic kidney disease patients undergoing hemodialysis without adverse events or negative cardiovascular responses. Aerobic training may prevent a decline in body composition and knee joint muscle function due to inactivity in chronic kidney disease patients. Clinically, aerobic training may initially be adapted to maintain overall physical function or improve quality of life in chronic kidney disease patients undergoing hemodialysis.

  13. Using gamma distribution to determine half-life of rotenone, applied in freshwater.

    PubMed

    Rohan, Maheswaran; Fairweather, Alastair; Grainger, Natasha

    2015-09-15

    Following the use of rotenone to eradicate invasive pest fish, a dynamic first-order kinetic model is usually used to determine the half-life and rate at which rotenone dissipated from the treated waterbody. In this study, we investigate the use of a stochastic gamma model for determining the half-life and rate at which rotenone dissipates from waterbodies. The first-order kinetic and gamma models produced similar values for the half-life (4.45days and 5.33days respectively) and days to complete dissipation (51.2days and 52.48days respectively). However, the gamma model fitted the data better and was more flexible than the first-order kinetic model, allowing us to use covariates and to predict a possible range for the half-life of rotenone. These benefits are particularly important when examining the influence that different environmental factors have on rotenone dissipation and when trying to predict the rate at which rotenone will dissipate during future operations. We therefore recommend that in future the gamma distribution model is used when calculating the half-life of rotenone in preference to the dynamic first-order kinetics model. PMID:25965037

  14. OSIRIS-SR: A Safety Ring for self-healing distributed composite service execution

    Microsoft Academic Search

    Nenad StojniHeiko Schuldt; Heiko Schuldt

    2012-01-01

    The advent of service-oriented architectures has strongly facilitated the development and deployment of large-scale distributed applications. The middleware for orchestrating applications that consist of several distributed services has to be inherently distributed as well, in order to provide a high degree of scalability and to avoid any single point of failure. Self-healing execution of composite services requires replicated control metadata

  15. Network considerations for distributed multimedia object composition and communication

    Microsoft Academic Search

    T. D. C. Little; A. Ghafoor

    1990-01-01

    Terminology is defined, and issues related to providing temporal data integration in a distributed environment are identified. Current technological approaches to the issues are reviewed, and the state of the art is assessed. A unified model for synchronization at three levels, based on previously reviewed approaches, is presented. Directions for future efforts are indicated

  16. Nutrient composition and respiration characteristics of silkworms in the Bioregenerative Life Support System

    NASA Astrophysics Data System (ADS)

    Tong, Ling; Yu, Xiaohui; Liu, Hong

    As the appropriate space animal candidate, silkworm(Bombyx Mori L.) can supply animal food for taikonauts and consume inedible parts of plants in Bioregenerative Life Support Sys-tem(BLSS). Due to the features of BLSS, the silkworm breeding method in the system differ-ent from the conventional one is feeding the silkworm in the first three developing stages with mulberry leaves and with lettuce leaves in the latter two developing stages. Therefore, it is nec-essary to investigate the biochemical components and respiration characteristics of silkworms raised with this method to supply data bases for the inclusion of silkworms in the system to conduct system experiments. The nutrient compositions of silkworm powder (SP) which are the grinded and freeze-dried silkworm on the 3rd day in the fifth developing stage containing protein, fat, vitamins, minerals and fatty acids were determined with international standard analyzing methods in this study. The results showed that SP was rich in protein and amino acids. There were twelve kinds of essential vitamins, nine kinds of minerals and twelve kinds of fatty acids in SP. In contrast, SP had much better nutrient components than snail, fish, chicken, beef and pork as animal food for crew members. Moreover, 359 kCal can be generated per 100g of SP (dry weight). The respirations of silkworm during its whole growing process under two main physiological statuses which were eating and non-eating leaves were studied. According to the results measured by the animal respiration measuring system, there were much difference among the respirations of silkworms under the two main physiological statuses. The amounts of O2 inhaled and CO2 exhaled by the silkworms when they were eating leaves were more than those under the non-eating status. Even under the same status, the respiration characteristics of silkworms in five different developing stages were also different from one an-other. The respiratory quotients of silkworms under two statuses are largely different (eating F=3.191, P<0.05; non-eating F=2.935, P <0.05). Moreover, the amounts of O2 inhaled and CO2 exhaled by the silkworms in the first three developing stages were much more than those of the silkworms in the latter two developing stages per unit weight of leaves. These results concerning the nutrient compositions and respiration characteristics of silkworms can provide valuable data for the establishment of complex bioregenerative life support systems including different biological units in the lunar or mars bases in the future.

  17. Corona Characteristics of Distribution Line in Contact with Conductive Material and Life Estimation of Conductor Insulation

    NASA Astrophysics Data System (ADS)

    Yamashita, Takahiko; Fujishima, Tomoyuki; Kuba, Hiroyuki

    In relation to the accidents due to bird nests in contact with overhead distribution lines, the authors investigated on life estimation of conductor insulation. The accident is often caused by crow or magpie. There is a region in which magpie is being specified to the protected bird in Japan. In that region, the nest in the breeding season can not be removed easily. Recently, metal wires are used for the nest material. When this conductive material is in contact with the distribution line and the arm, corona discharge will occur. The conductor insulation of the distribution line receives deterioration and there is a possibility of causing the accident. In this study, acceleration test was done to examine time from nest building to causing the accident in the distribution line. The acceleration factor based on the charge amount of corona and the influence of the applied voltage on corona characteristics were discussed. Moreover, the life of the conductor insulation was discussed from the V-t characteristics and the acceleration factor.

  18. Identifying the failure mechanism in accelerated life tests by two-parameter lognormal distributions

    NASA Astrophysics Data System (ADS)

    Chunsheng, Guo; Yanfeng, Zhang; Ning, Wan; Hui, Zhu; Shiwei, Feng

    2014-08-01

    The failure mechanism stimulated by accelerated stress in the degradation may be different from that under normal conditions, which would lead to invalid accelerated life tests. To solve the problem, we study the relation between the Arrhenius equation and the lognormal distribution in the degradation process. Two relationships of the lognormal distribution parameters must be satisfied in the conclusion of the unaltered failure mechanism, the first is that the logarithmic standard deviations must be equivalent at different temperature levels, and the second is that the ratio of the differences between logarithmic means must be equal to the ratio of the differences between reciprocals of temperature. The logarithm of distribution lines must simultaneously have the same slope and regular interval lines. We studied the degradation of thick-film resistors in MCM by accelerated stress at four temperature levels (390, 400, 410 and 420 K), and the result agreed well with our method.

  19. Optimizing Powder Distribution in Production of Surface Nano-Composite via Friction Stir Processing

    NASA Astrophysics Data System (ADS)

    Heydarian, Arash; Dehghani, Kamran; Slamkish, Taymor

    2014-06-01

    Notwithstanding the extensive interest in using friction stir processing (FSP) for producing metal matrix composite (MMC), more uniform powder distribution along the composite zone is still needed. In most studies, one groove is machined out of the specimen, filled with powder, and then processed by identical passes. In this investigation, an innovative technique was used that involved machining out of three gradient grooves with increasing depth from the advancing side to the retreating side instead of using a conventional sample with just a groove. Macro, optical, and scanning electron microscopy (SEM) images and microhardness test were used to evaluate the powder distribution. The images indicated that the most uniform distribution of SiC particles in the whole composite zone was related to a three-gradient grooves sample. Microohardness measurement of a three-gradient grooves sample, carried out along the cross section and perpendicular to the traverse direction of FSP, experiences less fluctuation in hardness compared with other techniques.

  20. Loading Analysis of Composite Wind Turbine Blade for Fatigue Life Prediction of Adhesively Bonded Root Joint

    NASA Astrophysics Data System (ADS)

    Salimi-Majd, Davood; Azimzadeh, Vahid; Mohammadi, Bijan

    2015-06-01

    Nowadays wind energy is widely used as a non-polluting cost-effective renewable energy resource. During the lifetime of a composite wind turbine which is about 20 years, the rotor blades are subjected to different cyclic loads such as aerodynamics, centrifugal and gravitational forces. These loading conditions, cause to fatigue failure of the blade at the adhesively bonded root joint, where the highest bending moments will occur and consequently, is the most critical zone of the blade. So it is important to estimate the fatigue life of the root joint. The cohesive zone model is one of the best methods for prediction of initiation and propagation of debonding at the root joint. The advantage of this method is the possibility of modeling the debonding without any requirement to the remeshing. However in order to use this approach, it is necessary to analyze the cyclic loading condition at the root joint. For this purpose after implementing a cohesive interface element in the Ansys finite element software, one blade of a horizontal axis wind turbine with 46 m rotor diameter was modelled in full scale. Then after applying loads on the blade under different condition of the blade in a full rotation, the critical condition of the blade is obtained based on the delamination index and also the load ratio on the root joint in fatigue cycles is calculated. These data are the inputs for fatigue damage growth analysis of the root joint by using CZM approach that will be investigated in future work.

  1. Kinetics of Formation of Molecular Weight Distribution of Epoxy Composite

    NASA Astrophysics Data System (ADS)

    Komar, Lyudmila A.; Kondyurin, Alexey; Svistkov, Alexander L.

    Curing of epoxy matrix prepreg in free space environment is a complex problem. A simulation of the chemical reaction, evaporation and radiation effects in the matrix is a way to understand and predict the curing process. We have developed a mathematical apparatus of the epoxy resin kinetics in term of molecular weight distribution (MWD), which includes the polymerization mechanism of bifunctional epoxy and sixfunctional triethylenetetraamine (TETA) molecules. The mathematical model for a number of molecules with the mass m at time t is based on the following equation $ beta(t,m)=m_{am} / m sum(6}_{i=0) alpha(am) _i (t,m)+ m_{ep} / m sum(2}_{i=0) alpha(ep) _i (t,m), where m_{am} and m_{ep} are the masses of one amine block and one epoxy block, respectively; alpha^{am}_i (t,m) is the MWD near the TETA blocks with the chemical bonds i at time t for the mass values m>0; alpha_i^{ep}(t,m) is the MWD parameters of the epoxy blocks with chemical bonds i at time t for the mass values m>0. For the distribution densities alpha^{am}_i (t,m) and alpha_i^{ep}(t,m), we propose the differential system of equations, which has been solved by applying boundary conditions which are based on the results of chromatography and infrared spectroscopy measurements of the epoxy matrix having different concentration of the hardener. For the initial MWD we accept a Gaussian distribution with parameters alpha^{am}_0 (t,m_1) =146 amu, alpha_0^{ep}(t,m_1) =340 amu and alpha_1^{ep}(t,m_1) =624 amu. Dispersion of the molecular weight for the initial distribution equals to 25 amu. A portion of TETA molecules in the fraction was 25%, and the portion of epoxy molecules with i=0 and i=1 was 67.5% and 7.5%$, respectively. Solutions were obtained at mass step equals to 5 amu and at time step equals to 0.25 min over the interval from 0 to 500 min. The model gives a full kinetic of MWD during the curing reaction. The study is supported by the RFBR (grants N 12-08-00970-a and N 14-08-96011-r-ural-a).

  2. Application of a Fiber Optic Distributed Strain Sensor System to Woven E-Glass Composite

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Lopatin, Craig

    2001-01-01

    A distributed strain sensing system utilizing a series of identically written Bragg gratings along an optical fiber is examined for potential application to Composite Armored Vehicle health monitoring. A vacuum assisted resin transfer molding process was used to fabricate a woven fabric E-glass/composite panel with an embedded fiber optic strain sensor. Test samples machined from the panel were mechanically tested in 4-point bending. Experimental results are presented that show the mechanical strain from foil strain gages comparing well to optical strain from the embedded sensors. Also, it was found that the distributed strain along the sample length was consistent with the loading configuration.

  3. Distribution patterns of different carbon nanostructures in silicon nitride composites.

    PubMed

    Tapasztó, Orsolya; Markó, Márton; Balázsi, Csaba

    2012-11-01

    The dispersion properties of single- and multi-walled carbon nanotubes as well as mechanically exfoliated few layer graphene flakes within the silicon nitride ceramic matrix have been investigated. Small angle neutron scattering experiments have been employed to gain information on the dispersion of the nano-scale carbon fillers throughout the entire volume of the samples. The neutron scattering data combined with scanning electron microscopy revealed strikingly different distribution patterns for different types of carbon nanostructures. The scattering intensities for single wall carbon nanotubes (SWCNTs) reveal a decay exponent characteristic to surface fractals, which indicate that the predominant part of nanotubes can be found in loose networks wrapping the grains of the polycrystalline matrix. By contrast, multi wall carbon nanotubes (MWCNTs) were found to be present mainly in the form of bulk aggregate structures, while few-layer graphene (FLG) flakes have been individually dispersed within the host matrix, under the very same preparation and processing conditions. PMID:23421284

  4. Perchlorate in The Great Lakes: Distribution, Isotopic Composition and Origin

    NASA Astrophysics Data System (ADS)

    Poghosyan, A.; Sturchio, N. C.; Jackson, W. A.; Guan, Y.; Eiler, J. M.; Hatzinger, P. B.

    2013-12-01

    Concentrations, stable chlorine and oxygen isotopic compositions, and 36Cl abundances of perchlorate were investigated in the five Laurentian Great Lakes. Samples were collected during monitoring cruises in 2007 and 2008 of the U.S. EPA's RV Lake Guardian and in 2010 at the water supply intake of Marquette, MI on the southern shore of Lake Superior. Concentrations of perchlorate were measured by IC/MS/MS at 24 locations, including one or two depth profiles in each lake. Mean concentrations (?g/L) are: Superior, 0.06 × 0.01; Michigan, 0.10 × 0.01; Huron, 0.11 × 0.01; Erie, 0.08 × 0.01, and Ontario, 0.09 × 0.01. Concentration vs. depth is nearly constant in each lake, indicating well-mixed conditions. Perchlorate was extracted from near-surface water by passing 15,000 to 80,000 L of water through 1-L cartridges containing Purolite A530E bifunctional anion-exchange resin. In the laboratory, perchlorate was eluted from the resin, purified, and precipitated as a >99% pure crystalline phase. Milligram amounts were recovered from each lake. Chlorine and oxygen isotopic analyses were performed at Caltech using the Cameca 7f-GEO SIMS instrument, following validation of the SIMS method with analyses of USGS-37 and USGS-38 isotopic reference materials. Results indicate a relatively narrow range in ?37Cl values (+2.9 to +3.9 ‰) and a wider range in ?18O values (-4.0 to +4.1 ‰), with a general geographic trend of increasing ?18O from west to east. Oxygen-17 was measured at UIC using dual-inlet IRMS of O2 produced by decomposition of KClO4. Great Lakes perchlorate has mass-independent oxygen isotopic variations with positive ?17O values (+1.6 ‰ to +2.7 ‰) divided into two distinct groups: Lake Superior (+2.7 ‰) and the other four lakes (~ +1.7 ‰). The isotopic data indicate that perchlorate is dominantly of natural origin, having stable isotopic compositions resembling those of perchlorate from pre-industrial groundwaters in the western USA. The 36Cl/Cl ratios decrease from Lake Superior (66,500×10-15) to Lake Ontario (7,400×10-15). The high 36Cl/Cl ratios in the lakes having longer water residence times may be explained by retention of perchlorate formed during the time of the 36Cl bomb pulse (1952-1964). Mass balance of perchlorate indicates that substantial biodegradation or uptake of perchlorate may occur in Lake Erie. 36Cl/Cl results confirm that perchlorate in the Great Lakes has dominantly natural origin. These data provide better constraints on possible perchlorate source(s), mixing proportions, and isotopic exchange or fractionation processes within the lakes, as well as better estimates of the regional atmospheric deposition flux of perchlorate and the 36Cl abundance of bomb-pulse perchlorate.

  5. Characterization of Cyanobacterial Hydrocarbon Composition and Distribution of Biosynthetic Pathways

    PubMed Central

    Coates, R. Cameron; Podell, Sheila; Korobeynikov, Anton; Lapidus, Alla; Pevzner, Pavel; Sherman, David H.; Allen, Eric E.; Gerwick, Lena; Gerwick, William H.

    2014-01-01

    Cyanobacteria possess the unique capacity to naturally produce hydrocarbons from fatty acids. Hydrocarbon compositions of thirty-two strains of cyanobacteria were characterized to reveal novel structural features and insights into hydrocarbon biosynthesis in cyanobacteria. This investigation revealed new double bond (2- and 3-heptadecene) and methyl group positions (3-, 4- and 5-methylheptadecane) for a variety of strains. Additionally, results from this study and literature reports indicate that hydrocarbon production is a universal phenomenon in cyanobacteria. All cyanobacteria possess the capacity to produce hydrocarbons from fatty acids yet not all accomplish this through the same metabolic pathway. One pathway comprises a two-step conversion of fatty acids first to fatty aldehydes and then alkanes that involves a fatty acyl ACP reductase (FAAR) and aldehyde deformylating oxygenase (ADO). The second involves a polyketide synthase (PKS) pathway that first elongates the acyl chain followed by decarboxylation to produce a terminal alkene (olefin synthase, OLS). Sixty-one strains possessing the FAAR/ADO pathway and twelve strains possessing the OLS pathway were newly identified through bioinformatic analyses. Strains possessing the OLS pathway formed a cohesive phylogenetic clade with the exception of three Moorea strains and Leptolyngbya sp. PCC 6406 which may have acquired the OLS pathway via horizontal gene transfer. Hydrocarbon pathways were identified in one-hundred-forty-two strains of cyanobacteria over a broad phylogenetic range and there were no instances where both the FAAR/ADO and the OLS pathways were found together in the same genome, suggesting an unknown selective pressure maintains one or the other pathway, but not both. PMID:24475038

  6. Size and composition distribution of fine particulate matter emitted from wood burning, meat charbroiling, and cigarettes

    SciTech Connect

    Kleeman, M.J.; Schauer, J.J.; Cass, G.R.

    1999-10-15

    A dilution source sampling system is augmented to measure the size-distributed chemical composition of fine particle emissions from air pollution sources. Measurements are made using a laser optical particle counter (OPC), a differential mobility analyzer/condensation nucleus counter (DMA/CNC) combination, and a pair of microorifice uniform deposit impactors (MOUDIs). The sources tested with this system include wood smoke (pine, oak, eucalyptus), meat charbroiling, and cigarettes. The particle mass distributions from all wood smoke sources have a single mode that peaks at approximately 0.1--0.2 {micro}m particle diameter. The smoke from meat charbroiling shows a major peak in the particle mass distribution at 0.1--0.2 {micro}m particle diameter, with some material present at larger particle sizes. Particle mass distributions from cigarettes peak between 0.3 and 0.4 {micro}m particle diameter. Chemical composition analysis reveals that particles emitted from the sources tested here are largely composed of organic compounds. Noticeable concentrations of elemental carbon are found in the particles emitted from wood burning. The size distributions of the trace species emissions from these sources also are presented, including data for Na, K, Ti, Fe, Br, Ru, Cl, Al, Zn, Ba, Sr, V, Mn, Sb, La, Ce, as well as sulfate, nitrate, and ammonium ion when present in statistically significant amounts. These data are intended for use with air quality models that seek to predict the size distribution of the chemical composition of atmospheric fine particles.

  7. Microstructural effects on the residual stress and stress distribution in WC-Ni composites

    SciTech Connect

    Seol, K.

    1990-01-01

    Effects of microstructure on the differential thermal residual stresses and their distributions for model WC-Ni cemented carbide composites were determined by neutron powder diffraction. Absolute strain and stress values were obtained from the difference in WC cell parameters in a stress-free, loose WC powder and the WC phase in the composite over the temperature range 100 to 900 K. The resultant volume averaged strains in the hexagonal WC particles were highly anisotropic, with the strains in the a-direction exceeding those in the c-direction. This was correctly predicted by Eshelby's equivalent inclusion method assuming the particle shape as an oblate spheroid. In addition, the strain distribution in the WC and Ni binder phases were determined by a modified integral peak breadth method of particle size-strain analysis using the peak breadths in the reference powder and the composite. Strain distribution cannot be converted into stress distribution directly because the stresses due to the WC particle aspect ratio are not hydrostatic and because the fraction of each effect on the total strain distribution is not known. Therefore, quantitative stress distribution values were not determined.

  8. COMPOSITION, ABUNDANCE, AND DISTRIBUTION OF ZOOPLANKTON IN THE NEW YORK BIGHT, SEPTEMBER 1974-SEPTEMBER 1975

    E-print Network

    COMPOSITION, ABUNDANCE, AND DISTRIBUTION OF ZOOPLANKTON IN THE NEW YORK BIGHT, SEPTEMBER 1974-SEPTEMBER 1975 DAVID C. JUDKINS,l CREIGHTON D. WIRICK,l AND WAYNE E. ESAIAS' ABSTRACT Zooplankton taxa were during autumn 1974 and summer 1975, an offshore (>50 m water depth) zooplankton abundance maximum

  9. DISTRIBUTION OF PROTEIN COMPOSITION IN BREAD WHEAT FLOUR MILL STREAMS AND RELATIONSHIP TO BREADMAKING QUALITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat protein quantity and composition are important parameters for wheat baking quality. The objective of this study was to use fractionation techniques to separate the proteins of flour mill streams into various protein fractions, to examine the distribution of these protein fractions, and to esta...

  10. Automated Shape Composition Based on Cell Biology and Distributed Genetic Programming

    E-print Network

    Fernandez, Thomas

    Automated Shape Composition Based on Cell Biology and Distributed Genetic Programming Linge Bai lb to developmental biology for concepts that lead to a more organic, cell-biology-inspired approach to shape of Computer Science Drexel University ABSTRACT Motivated by the ability of living cells to form specific

  11. Estimation of Distributed Parameters in Permittivity Models of Composite Dielectric Materials Using

    E-print Network

    for use in characteriz- ing damage and degradation of these materials. One such process which is popular to monitor material damage and/or degradation. Typically one would assume a particular combinationEstimation of Distributed Parameters in Permittivity Models of Composite Dielectric Materials Using

  12. Pigment composition and size distribution of phytoplankton in a confined Mediterranean salt marsh ecosystem

    Microsoft Academic Search

    Rocío López-Flores; Dani Boix; Anna Badosa; Sandra Brucet; Xavier D. Quintana

    2006-01-01

    Pigment composition and size distribution of phytoplankton were analysed in a group of Mediterranean salt marshes, where hydrology is dominated by sudden inputs during sea storms, followed by long periods of confinement. These marshes are characterized by a low inorganic–organic nutrient ratio, and inorganic nitrogen is especially scarce due to denitrification. Nutrients were the main factor affecting phytoplankton biomass, while

  13. Composition, Abundance and Distribution of Zooplankton in the Bay of Bengal

    Microsoft Academic Search

    Issarapon Jitlang; Sunan Pattarajinda; Ramananda Mishra

    A 58 days-collaborative survey (25 October-21 December, 2007) of the BIMSTEC member countries (Bangladesh, India, Myanmar, Sri Lanka, Nepal and Thailand) was carried on in the Bay of Bengal in order to elucidate the fertility of the area as a new fishery ground. The purpose of this study was to determine the composition, abundance and distribution of zooplankton in 3

  14. DAMAGE DETECTION IN COMPOSITE STRUCTURES FROM FIBRE OPTIC DISTRIBUTED STRAIN MEASUREMENTS

    E-print Network

    Boyer, Edmond

    DAMAGE DETECTION IN COMPOSITE STRUCTURES FROM FIBRE OPTIC DISTRIBUTED STRAIN MEASUREMENTS Alfredo Madrid, 28040 MADRID-SPAIN alfredo.guemes@upm.es ABSTRACT Two approaches may be followed to obtain damage of backscattered radiation), placing the plain optical fibre at the region where damage is expected. Because of its

  15. The use of fractal dimension calculation algorithm to determine the nature of autobiographical memories distribution across the life span

    NASA Astrophysics Data System (ADS)

    Mitina, Olga V.; Nourkova, Veronica V.

    In the given research we offer the technique for the calculation of the density of events which people retrieve from autobiographical memory. We wanted to prove a non-uniformity nature of memories distribution in the course of time and were interested with the law of distribution of these events during life course.

  16. Half life and changes in the composition of a perfluorochemical emulsion within the vascular system of rats.

    PubMed

    Lutz, J; Stark, M

    1987-09-01

    The decline of the concentration of perfluorochemicals (PFC) after a single injection of three different doses was studied in the circulation of rats. The doses used amounted to 4.4, 10 and 14 g/kg body weight of Fluosol-DA, an emulsion of 7 parts of perfluorodecalin (FDC) and 3 parts of perfluorotripropylamine (FTPA). This also allowed testing of the composition of the emulsion remaining in the circulation and of that found in the liver. After two days a decrease of the half life from 34.0 +/- 0.7 to 17.1 +/- 4.3 h was found within the circulation at the highest dose. At the same time a change in the composition of the emulsion in the blood stream occurred, favouring the fraction of FTPA. FTPA increased from 28.3 +/- 1.4 to 54.4 +/- 8.1% on the fourth day. Whereas in the cells of the liver PFC droplets may be broken up, freed from their surfactant layer and handled according to their individual components, for PFC in the blood stream an unchanged composition should be assumed. Both results, the decreasing half life and the change in composition of the circulating emulsion may best be explained by a shrinking and instability of the emulgator film, showing the necessity for development of a superior surfactant. PMID:3684504

  17. Reliability and life prediction of ceramic composite structures at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Duffy, Stephen F.; Gyekenyesi, John P.

    1994-01-01

    Methods are highlighted that ascertain the structural reliability of components fabricated of composites with ceramic matrices reinforced with ceramic fibers or whiskers and subject to quasi-static load conditions at elevated temperatures. Each method focuses on a particular composite microstructure: whisker-toughened ceramics, laminated ceramic matrix composites, and fabric reinforced ceramic matrix composites. In addition, since elevated service temperatures usually involve time-dependent effects, a section dealing with reliability degradation as a function of load history has been included. A recurring theme throughout this chapter is that even though component failure is controlled by a sequence of many microfailure events, failure of ceramic composites will be modeled using macrovariables.

  18. Fail-safe sensor distributions for impact detection in composite materials

    NASA Astrophysics Data System (ADS)

    Staszewski, W. J.; Worden, K.; Wardle, R.; Tomlinson, G. R.

    2000-06-01

    This paper studies the problem of optimal sensor placement for impact detection and location in composite materials. The study involves a simple impact experiment on a composite box panel. The time-varying strain data are measured using piezoceramic sensors. An effective impact detection procedure is established using a neural network approach. The procedure determines the location and amplitude of impacts. A genetic algorithm is used to determine the optimum sensor positions for a diagnostic system. The main object of the paper is to study fail-safe distributions, i.e. those whose sub-distributions also have a low probability of detection error. The results are validated against an exhaustive search. The study shows that genetic algorithms combined with neural networks can be effectively used to find near-optimal sensor distributions for damage detection. The methods presented are generic and can be used in similar sensor position problems.

  19. A piezolaminated composite degenerated shell finite element for active control of structures with distributed piezosensors and actuators

    Microsoft Academic Search

    V. Balamurugan; S. Narayanan

    2008-01-01

    This paper deals with the formulation of a nine-noded piezolaminated degenerated shell finite element for modeling and analysis of multilayer composite general shell structures with bonded\\/embedded distributed piezoelectric sensors and actuators. The distributed PZT sensors and actuators used in the composite smart structures are relatively thin and could have arbitrary variation of curvatures and thicknesses. They cannot be modeled with

  20. Major elements composition, Li distribution and isotopic composition in peridotite xenoliths from Allegre and Mont Coupet (French Massif Central)

    NASA Astrophysics Data System (ADS)

    Xiaoyan, Gu; Etienne, Deloule; Lyderic, France; Jannick, Ingrin

    2014-05-01

    The peridotite xenoliths from two localities (the Ringue quarry in Allegre; Mont Coupet) belong to the Massif Central southern domain, which have been accredited as a circumcratonic segment and been rejuvenated during the Variscan orogeny (Lenoir et al. 2000). The Ringue quarry is opened in a lava lake and, in contrast, Mont Coupet is a strombolian eruptive volcano. Major element compositions, Li distribution and isotope compositions in minerals from these xenoliths were measured to describe the evolution of the sub-continental lithospheric mantle, and to look for Li exchange during the melt-rock interaction. As for major element compositions, the samples from two localities fall into the off-craton field (Rudnick et al., 2004) and the compositional ranges of the southern domain of the French Massif Central (Downes et al., 2003). They have also been imprinted by mantle metasomatism, which engendered much higher Mg# of cpx (up to 93.5) relative to their co-existing olivines (89.2 to 91.5). In the Allegre samples, large variations between the equilibration temperatures of mineral cores and rims indicate disequilibrium resulting from mantle metasomatism. Cpx display enriched Li contents (up to 24 ppm) and Li partitioning between cpx and olivine/opx strongly deviates from the equilibrated trend (Seitz and Woodland, 2000), suggestive of their interaction with mafic silicate melts and/or fluids with high Li contents. The highly negative ?7Li values (down to -25o ) compared to the primary mantle value of 4±2o (Rudnick and Ionov, 2007) and the large inter-mineral Li isotope fractionations attest for Li exchange with melts and/or fluids during metasomatic events. Mont Coupet samples display equilibrated Li distribution and isotopic composition at the thin section scale, but an inverse relationship between the Li contents and Li isotope compositions between the different samples, indicating a large-scale Li diffusion process, occurring before the xenoliths exhumation. In conclusion, the different types of host magmas should be a significant factor that leads to these extremely diverse characteristics of Li distribution and isotope compositions in the samples from Allegre and Mont Coupet. In the lava lake, host magmas have kept relatively long-term high temperatures and this provided time for Li to diffuse from infiltrated metasomatic melts or host magmas. On the contrary, Mont Coupet has cooled rapidly and the xenoliths could preserve the geochemical state of Li in the mantle depth. Lenoir et al, 2000, Earth Planet. Sci. Lett. 181, 359- 375. Rudnick et al., 2004, Lithos 77, 609-637. Downes et al., 2003, Chem. Geol. 200, 71-87. Seitz and Woodland, 2000, Chem. Geol. 166, 47-64. Rudnick and Ionov, 2007, Earth Planet. Sci. Lett. 256, 278-293.

  1. Frequency Distributions of Geochemical Data, Scaling Laws, and Properties of Compositions

    NASA Astrophysics Data System (ADS)

    Buccianti, Antonella

    2014-11-01

    Many random processes occur in geochemistry. Accurate predictions of the manner in which elements or chemical species interact with each other are needed to construct models able to treat the presence of random components. Although modelling of frequency distributions with some probabilistic models (for example Gaussian, log-normal, Pareto) has been well discussed in several fields of application, little attention has been devoted to the features of compositional data and, in particular, to their multivariate nature. In this contribution an approach coherent with the properties of compositional information is proposed and used to investigate the shape of the frequency distribution of geochemical indices obtained by robust multivariate analysis. The purpose is to understand data-generation processes from the perspective of compositional theory. The approach is based on use of transformations of the log-ratio family, each with peculiar theoretical and practical advantages, depending on the statistical methods adopted. Accordingly, because, in compositional data, all the relevant information about one term (x i ) of a D-part composition is contained in the ratios to each of the remaining parts x 2,…, x D , analysis of single variables is abandoned. The proposed methodology directs attention to modelling of the frequency distribution of more complex indices, linking all the terms of the composition to better represent the dynamics of geochemical processes. An example of its application is presented and discussed on the basis of consideration of the chemistry of 616 ocean floor basaltic (OFB) glasses from the abyssal volcanic glass data file (AVGDF) of the Smithsonian Institution.

  2. Frequency Distributions of Geochemical Data, Scaling Laws, and Properties of Compositions

    NASA Astrophysics Data System (ADS)

    Buccianti, Antonella

    2015-07-01

    Many random processes occur in geochemistry. Accurate predictions of the manner in which elements or chemical species interact with each other are needed to construct models able to treat the presence of random components. Although modelling of frequency distributions with some probabilistic models (for example Gaussian, log-normal, Pareto) has been well discussed in several fields of application, little attention has been devoted to the features of compositional data and, in particular, to their multivariate nature. In this contribution an approach coherent with the properties of compositional information is proposed and used to investigate the shape of the frequency distribution of geochemical indices obtained by robust multivariate analysis. The purpose is to understand data-generation processes from the perspective of compositional theory. The approach is based on use of transformations of the log-ratio family, each with peculiar theoretical and practical advantages, depending on the statistical methods adopted. Accordingly, because, in compositional data, all the relevant information about one term ( x i ) of a D-part composition is contained in the ratios to each of the remaining parts x 2,…, x D , analysis of single variables is abandoned. The proposed methodology directs attention to modelling of the frequency distribution of more complex indices, linking all the terms of the composition to better represent the dynamics of geochemical processes. An example of its application is presented and discussed on the basis of consideration of the chemistry of 616 ocean floor basaltic (OFB) glasses from the abyssal volcanic glass data file (AVGDF) of the Smithsonian Institution.

  3. Relationship between iron-meteorite composition and size: Compositional distribution of irons from North Africa

    NASA Astrophysics Data System (ADS)

    Wasson, John T.

    2011-04-01

    During the past three decades many iron meteorites have been collected from the deserts of North Africa. Almost all are now characterized, and the distribution among classes is found to be very different from those that were in museums prior to the collection of meteorites from hot and cold (Antarctica) deserts. Similar to the iron meteorites from Antarctica, the irons from Northwest Africa include a high fraction of ungrouped irons and of minor subgroups of group IAB. The different distribution is attributed to the small median size of the desert meteorites (˜1.3 kg in North African irons, ˜30 kg in non-desert irons). It appears that a sizable fraction of these small (several centimeter) masses constitute melt pockets produced by impacts in chondritic regoliths; they were never part of a large (meter-to-kilometer) magma bodies. As a result, a meter-size fragment ejected from the regolith of the asteroid may contain several of these small metallic masses. It may be that such stochastic sampling effects enhanced the fraction of IAB-sHL irons among the irons from Northwest Africa. The variety observed in small meteoroids is also enhanced because (relative to large) small fragments are more efficiently ejected from asteroids and because the orbital parameters of small meteoroids are more strongly affected by collisions and drag effects, they evolve to have Earth-crossing perihelia more rapidly than large meteoroids; as a result, the set of small meteoroids tends to sample a larger number of parent asteroids than does the set of larger meteoroids.

  4. Electrical Resistance of SiC/SiC Ceramic Matrix Composites for Damage Detection and Life-Prediction

    NASA Technical Reports Server (NTRS)

    Smith, Craig; Morscher, Gregory; Xia, Zhenhai

    2009-01-01

    Ceramic matrix composites (CMC) are suitable for high temperature structural applications such as turbine airfoils and hypersonic thermal protection systems due to their low density high thermal conductivity. The employment of these materials in such applications is limited by the ability to accurately monitor and predict damage evolution. Current nondestructive methods such as ultrasound, x-ray, and thermal imaging are limited in their ability to quantify small scale, transverse, in-plane, matrix cracks developed over long-time creep and fatigue conditions. CMC is a multifunctional material in which the damage is coupled with the material s electrical resistance, providing the possibility of real-time information about the damage state through monitoring of resistance. Here, resistance measurement of SiC/SiC composites under mechanical load at both room temperature monotonic and high temperature creep conditions, coupled with a modal acoustic emission technique, can relate the effects of temperature, strain, matrix cracks, fiber breaks, and oxidation to the change in electrical resistance. A multiscale model can in turn be developed for life prediction of in-service composites, based on electrical resistance methods. Results of tensile mechanical testing of SiC/SiC composites at room and high temperatures will be discussed. Data relating electrical resistivity to composite constituent content, fiber architecture, temperature, matrix crack formation, and oxidation will be explained, along with progress in modeling such properties.

  5. Body composition and fat distribution among older Jat females: a rural-urban comparison.

    PubMed

    Kaur, Maninder; Talwar, Indu

    2011-10-01

    The aim of the present cross-sectional study is to describe and compare age related changes in body composition and fat patterning among rural and urban Jat females of Haryana State, India. A total of 600 females (rural=300, urban=300), ranging in age from 40 to 70 years were selected by the purposive sampling method. Body weight, height, two circumferences (waist and hip) and skinfold thickness at five different sites (biceps, triceps, calf, subscapular, and supra-iliac) were taken on each participant. To study total adiposity, indices such as body mass index (BMI), grand mean thickness (GMT), total body fat and percentage fat were analyzed statistically. The fat distribution pattern was studied using waist/hip ratio, subscapular/triceps ratio and responsiveness of five skinfold sites towards accumulation of fat at different sites with advancing age. Results indicate a decline in almost every dimension including level of fatness between the mid-fourth and mid-fifth decades of life in both rural and urban females. Urban Jat females were heavier (57.36 kg vs. 56.07 kg, p>0.05) and significantly taller (1553.3mm vs. 1534.5mm, p<0.001) than their rural counterparts. Urban females also exhibited higher mean values for both the circumferences, five skinfold thicknesses as well as for lean body mass, total fat and percentage fat than the rural females. This is also evident from their higher mean values for body mass index and grand mean thickness. Waist/hip ratio values in rural and urban females showed upper body fat predominance, with urban females having relatively more abdominal fat. Results of subscapular/triceps ratio showed that rural and urban females gained proportionally similar amounts of subcutaneous fat at trunk and extremity sites until 45 years of age. Subsequently trunk skinfolds increased relatively more in thickness. The magnitude of this increase was comparatively greater in rural females up to 55 years and among urban females from 55 to 70 years. The profiles of subcutaneous fat accumulation and sensitivity of each skinfold site also revealed more fat deposition in the trunk region compared to extremities in both rural and urban females. The present study demonstrated differential rates of fat redistribution among rural and urban females. PMID:21958971

  6. Fatigue behavior and life prediction of a SiC/Ti-24Al-11Nb composite under isothermal conditions

    SciTech Connect

    Barolotta, P.A.

    1991-01-01

    Metal Matrix Composites (MMC) and Intermetallic Matrix Composites (IMC) are potential material candidates for advanced aerospace application. As part of this study, a series of strain- and load-controlled fatigue tests were conducted on unidirectional SiC/Ti-24Al-11Nb (atomic%) composite at 425 and 815[degree]C. Several damage mechanism regimes were identified by using a strain-based representation of the data. Results from these tests were then used to address issues of test control modes, definition of failure, and testing techniques. Factors such as fiber volume ratio, number of plys, and temperature dependence are implicitly incorporated into a model. The model parameters were determined by using fatigue data at temperatures of 425 and 815[degree]C. Fatigue-life data from two independent sources were used to verify the model at temperatures of 650 and 760[degree]C. Cross-ply life data from specimens with ply lay-ups of [0/90][sub 2s] and [0/[plus minus]45/90][sub 2s] at 760[degree]C were also predicted. Correlation between experimental and predicted livers was found to be vary reasonable.

  7. Effect of HIV Infection on Body Composition and Fat Distribution in Rwandan Women

    PubMed Central

    Mutimura, Eugene; Anastos, Kathryn; Lin, Zheng; Cohen, Mardge; Binagwaho, Agnes; Kotler, Donald P.

    2015-01-01

    Objective To assess the association of HIV infection with body weight and composition in Rwandan women. Design Body weight and composition, the latter determined by bioelectrical impedance analysis (BIA) and by anthropometry, were compared in 620 HIV-positive and 211 HIV-negative participants. Associations of HIV with body composition were assessed, and t tests compared the groups. Results HIV-positive women were younger (?7.0 years, P < .001) and shorter (? 2.1 cm, P < .001). Mean body weight, body mass index (BMI), total body fat, and waist-to-hip ratio (WHR) were similar. Mean fat-free mass was 2.5% greater in HIV-negative participants, and 19% of HIV-positive group had BMI <18.5 kg/m2 versus 26% of the HIV-negative group (P < .05). CD4 counts and body composition were not associated. Conclusions Malnutrition was common in this cohort of Rwandan women. However, HIV infection was not associated with nutritional status. Factors other than malnutrition may influence quality-of-life outcomes in HIV-infected Rwandan women. Initiatives to improve nutritional status should be population-wide and not restricted to the HIV-infected population. PMID:20530472

  8. Effect of geometrical nonlinearity on stress distribution in laminated composites with curved structures

    NASA Astrophysics Data System (ADS)

    Akbarov, S. D.; Dzhamalov, Z. R.; Movsumov, E. A.

    1992-12-01

    The distribution of self-equilibrated normal and tangential stresses at the matrix-filler interface in composites with alternating periodically curved layers is investigated analytically in the case of uniaxial loading at infinity by uniformly distributed normal forces in the layer direction. The analysis is based on a piecewise homogeneous body model and employs three-dimensional elasticity equations in the geometrically nonlinear formulation. It is shown that the consideration of geometrical nonlinearity leads to a reduction of the self-equilibrated stresses in the case of tension and an increase of these stresses in the case of compression.

  9. Composition and ecological distribution of forest soil animal in Confucian graveyard of Qufu

    Microsoft Academic Search

    Liu Hong

    1999-01-01

    Soil animal communities of Secondary forest,Platycladus forest andQuercus acutissima forest in Confucian graveyard of Qufu were investigated. 3583 specimens were collected, belonging separately to 5 Phylums,\\u000a 11 Classes and 23 Orders. Two dominant groups and 9 common groups account for 94.45% of the total numbers. The soil animals\\u000a in these three forest habitats differ in composition, ecological distribution and important

  10. Simple Sequence Repeats in Escherichia coli: Abundance, Distribution, Composition, and Polymorphism

    Microsoft Academic Search

    Riva Gur-Arie; Cyril J. Cohen; Yuval Eitan; Leora Shelef; Eric M. Hallerman

    Computer-based genome-wide screening of the DNA sequence of Escherichia coli strain K12 revealed tens of thousands of tandem simple sequence repeat (SSR) tracts, with motifs ranging from 1 to 6 nucleotides. SSRs were well distributed throughout the genome. Mononucleotide SSRs were over-represented in noncoding regions and under-represented in open reading frames (ORFs). Nucleotide composition of mono- and dinucleotide SSRs, both

  11. Research on space charge distribution in composite of Low Density Polyethylene and Nano Silver

    Microsoft Academic Search

    Chuan Cai; Xuguang Li; Yi Yin; Zhe Li; Pingkai Jiang

    2008-01-01

    Double-solution mixture method was employed in the preparation of the composite of low density polyethylene\\/Nano-silver. Space charge distributions in samples with different nano-silver concentrations were measured using the pulsed electro-acoustic (PEA) method. In the experiment, samples were tested under three different levels of electrical stress, respectively: 10kV\\/mm, 30kV\\/mm and 50kV\\/mm. Discharge characteristics of the samples were examined as well. Test

  12. Source contributions to the size and composition distribution of urban particulate air pollution

    Microsoft Academic Search

    Michael J Kleeman; Glen R Cass

    1998-01-01

    A mechanistic air quality model has been constructed which is capable of predicting the contribution of individual emissions source types to the size- and chemical-composition distribution of airborne particles. This model incorporates all of the major aerosol processes relevant to regional air pollution studies including emissions, transport, deposition, gas-to-particle conversion and fog chemistry. In addition, the aerosol is represented as

  13. Size and composition distribution of fine particulate matter emitted from wood burning, meat charbroiling, and cigarettes

    Microsoft Academic Search

    Michael J. Kleeman; James J. Schauer; Glen R. Cass

    1999-01-01

    A dilution source sampling system is augmented to measure the size-distributed chemical composition of fine particle emissions from air pollution sources. Measurements are made using a laser optical particle counter (OPC), a differential mobility analyzer\\/condensation nucleus counter (DMA\\/CNC) combination, and a pair of microorifice uniform deposit impactors (MOUDIs). The sources tested with this system include wood smoke (pine, oak, eucalyptus),

  14. Model-based analysis of distributed real-time embedded system composition

    Microsoft Academic Search

    Gabor Madl; Sherif Abdelwahed

    2005-01-01

    Key challenges in distributed real-time embedded (DRE) system developments include safe composition of system components and mapping the functional specifications onto the target platform. Model-based verification techniques provide a way for the design-time analysis of DRE systems enabling rapid evaluation of design alternatives with respect to given performance measures before committing to a specific platform. This paper introduces a semantic

  15. Maximum natural frequencies of polymer composite micro-beams by optimum distribution of carbon nanotubes

    Microsoft Academic Search

    Hossein Rokni; Abbas S. Milani; Rudolf J. Seethaler

    2011-01-01

    Optimum distribution of multi-walled carbon nanotubes (MWCNTs) within a polymer composite micro-beam is sought to achieve its highest natural frequencies given a weight percent (wt.%) of MWCNTs. To this end, the micro-beam is divided into ten segments which are perfectly bonded to their neighbors. Each segment is made of low-viscosity, thermosetting polyester epoxy\\/amine resin LY-5052 and is reinforced by MWCNTs.

  16. Development of a fatigue-life methodology for composite structures subjected to out-of-plane load components

    NASA Technical Reports Server (NTRS)

    Sumich, Mark; Kedward, Keith T.

    1991-01-01

    The efforts to identify and implement a fatigue life methodology applicable to demonstrate delamination failures for use in certifying composite rotor blades are presented. The RSRA/X-Wing vehicle was a proof-of-concept stopped rotor aircraft configuration which used rotor blades primarily constructed of laminated carbon fiber. Delamination of the main spar during ground testing demonstrated that significant interlaminar stresses were produced. Analysis confirmed the presence of out-of-plane load components. The wear out (residual strength) methodology and the requirements for its implementation are discussed.

  17. Magnitude and distribution of stresses in composite resin and sound dentine interface with mechanical retentions

    PubMed Central

    Borie, Eduardo; Orsi, Iara-Augusta; Del Sol, Mariano

    2015-01-01

    Background Adhesive systems are constantly subjected to mechanical and chemical stresses that negatively impact the integrity and durability of the dentine-adhesive interface. Despite the lack of evidence to support or reject the clinical indication for mechanical retention, the potential further contribution of these preparations to the behavior of the composite resin-sound dentine bond has been rarely addressed. The authors evaluated by finite element analysis the effect of mechanical retention on the magnitude and distribution of stresses in a composite resin-sound dentin bonding interface when subjected to tensile and shear forces. Material and Methods A three-dimensional model was created based on three cylindrical volumes representing the sound dentin, adhesive system, and composite resin. From this main model, two models were designed to simulate dentine bonding: 1) a model with no mechanical retention, which considered flat adhesion; and 2) a model with retention, which considered four hemispherical holes on the dentine surface. Both groups were subjected to linear static analysis under tensile and shear loading of 200N. Results At the model with retentions’ bonding interface under tensile and shear loading, a concentration of Von Mises equivalent stress was observed within the retentions, with a reduction of those stresses on the bonding boundary surface. Conclusions Additional mechanical retention increases the tensile strength of the sound dentin-composite resin bonding interface, promoting a decrease in the magnitude of the stresses and their redistribution under tensile and shear loading. Key words:Adhesion, composite resins, dentine, finite element analysis. PMID:26155338

  18. Roles of maternal effects and nuclear genetic composition change across the life cycle of crop-wild hybrids.

    PubMed

    Alexander, Helen M; Emry, D Jason; Pace, Brian A; Kost, Matthew A; Sparks, Kathryn A; Mercer, Kristin L

    2014-07-11

    • Premise of the study: The fitness of an offspring may depend on its nuclear genetic composition (via both parental genotypes) as well as on genetic maternal effects (via only the maternal parent). Understanding the relative importance of these two genetic factors is particularly important for research on crop-wild hybridization, since traits with important genetic maternal effects (e.g., seed size) often differ among crops and their relatives. We hypothesized that the effects of these genetic factors on fitness components would change across the life cycle of hybrids.• Methods: We followed seed, plant size, and reproductive traits in field experiments with wild and four crop-wild hybrids of sunflower (Helianthus annuus), which differed in nuclear genetic composition and maternal parent (wild or F1 hybrid).• Key results: We identified strong genetic maternal effects for early life cycle characteristics, with seeds produced on an F1 mother having premature germination, negligible seed dormancy, and greater seedling size. Increased percentages of crop alleles also increased premature germination and reduced dormancy in seeds produced on a wild mother. For mature plants, nuclear genetic composition dominated: greater percentages of crop alleles reduced height, branching, and fecundity.• Conclusions: Particular backcrosses between hybrids and wilds may differentially facilitate movement of crop alleles into wild populations due to their specific features. For example, backcross seeds produced on wild mothers can persist in the seed bank, illustrating the importance of genetic maternal effects, whereas backcross individuals with either wild or F1 mothers have high fecundity, resulting from their wild-like nuclear genetic composition. PMID:25016007

  19. Chemosymbiotic species from the Gulf of Cadiz (NE Atlantic): distribution, life styles and nutritional patterns

    NASA Astrophysics Data System (ADS)

    Rodrigues, C. F.; Hilário, A.; Cunha, M. R.

    2013-04-01

    Previous work in the mud volcanoes from the Gulf of Cadiz (South Iberian Margin) revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of these species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (?13C, ?15N and ?34S) and investigate the intra-specific variation of isotope signatures within and between study sites. During our studies, we identified twenty siboglinidae and nine bivalve chemosymbiotic species living in fifteen mud volcanoes. Solemyid bivalves and tubeworms of the genus Siboglinum are widespread in the study area, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus) or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata). Species distribution suggests that different species may adjust their position within the sediment according to their particular needs, and to the intensity and variability of the chemical substrata supply. Tissue stable isotope signatures for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values) and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge on distributional patterns and resource partitioning of chemosymbiotic species and highlights how trophic fuelling varies on spatial scales with direct implications to seep assemblages and potentially to the biodiversity of continental margin.

  20. Software for analysis of chemical mixtures--composition, occurrence, distribution, and possible toxicity

    USGS Publications Warehouse

    Scott, Jonathon C.; Skach, Kenneth A.; Toccalino, Patricia L.

    2013-01-01

    The composition, occurrence, distribution, and possible toxicity of chemical mixtures in the environment are research concerns of the U.S. Geological Survey and others. The presence of specific chemical mixtures may serve as indicators of natural phenomena or human-caused events. Chemical mixtures may also have ecological, industrial, geochemical, or toxicological effects. Chemical-mixture occurrences vary by analyte composition and concentration. Four related computer programs have been developed by the National Water-Quality Assessment Program of the U.S. Geological Survey for research of chemical-mixture compositions, occurrences, distributions, and possible toxicities. The compositions and occurrences are identified for the user-supplied data, and therefore the resultant counts are constrained by the user’s choices for the selection of chemicals, reporting limits for the analytical methods, spatial coverage, and time span for the data supplied. The distribution of chemical mixtures may be spatial, temporal, and (or) related to some other variable, such as chemical usage. Possible toxicities optionally are estimated from user-supplied benchmark data. The software for the analysis of chemical mixtures described in this report is designed to work with chemical-analysis data files retrieved from the U.S. Geological Survey National Water Information System but can also be used with appropriately formatted data from other sources. Installation and usage of the mixture software are documented. This mixture software was designed to function with minimal changes on a variety of computer-operating systems. To obtain the software described herein and other U.S. Geological Survey software, visit http://water.usgs.gov/software/.

  1. Distribution of taxonomic classes and the compositional structure of the asteroid belt

    NASA Technical Reports Server (NTRS)

    Gradie, Jonathan C.; Chapman, Clark R.; Tedesco, Edward F.

    1989-01-01

    This paper reviews previous studies on the distribution of the asteroid taxonomic classes and analyzes the techniques, results, and interpretations of these studies, with special attention given to the strong and weak points of these studies and the important caveat for their interpretation. It is concluded that, in spite of the differences in class definition, the rather ordered heliocentric distribution of the composition is real and must be due to either primordial, evolutionary, or dynamical processes, or to a combination of all three. In general, the distribution of asteroid taxonomic classes is characterized by moderate-albedo asteroids dominant in the inner asteroid belt, and low-albedo asteroids prevalent in the outer belt and beyond.

  2. A GROUP ACCEPTANCE SAMPLING PLANS FOR TRUNCATED LIFE TESTS BASED ON THE INVERSE RAYLEIGH AND LOG-LOGISTIC DISTRIBUTIONS

    Microsoft Academic Search

    Muhammad Aslam; Chi-Hyuck Jun

    2009-01-01

    A group acceptance sampling plan from a truncated life test is designed when the lifetime of an item follows either an inverse Rayleigh or a log-logistic distribution, in which a multiple number of items as a group can be tested simultaneously in a tester. The minimum number of groups required for a given group size and the acceptance number is

  3. Distribution, growth and life cycle of the mesopelagic amphipod Primno abyssalis (Hyperiidea: Phrosinidae) in the southern Japan sea

    Microsoft Academic Search

    T. Ikeda

    1995-01-01

    The vertical distribution, growth, maturation, brood size and life cycle of the hyperiid amphipod Primno abyssalis (formerly P. macropa) were investigated using seasonal samples collected from Toyama Bay, southern Japan Sea, during the period June 1986 to September 1992. Over four different seasons of the year, P. abyssalis was most abundant in the 200 to 350 m strata at night

  4. Optimal spectral control of multiple waves in smart composite beams with distributed sensor-actuator configuration

    NASA Astrophysics Data System (ADS)

    Gopalakrishnan, S.; Mahapatra, Debiprosad R.

    2001-04-01

    A displacement based finite element model in Fourier domain coupled with Multi-input-multi-output (MIMO) optimal feedback control algorithm, called Active Spectral Element Model (ASEM) is presented. Implementation of this model, in this paper, is focused on local control of broadband waves in composite 2D beam network. Point sensors for velocity feedback and Piezoelectric Fiber Composite (PFC) for distributed longitudinal and bending actuation are considered in this study. The proposed model can accommodate generic sensor- actuator configuration in collocated as well as non-collocated form with PID feedback scheme. The formulation takes into account both sensor and actuator dynamics and nearfield effect on the sensors. Under this proposed framework of ASEM, the main objectives are (1) design of optimal feedback control parameters for multiple sensor-actuator configuration from distributed structural performance viewpoint and (2) capture various complex features of actively controlled broadband wave transmission in a simulation based realistic approach. The admissible sensor-actuator locations and connectivities are identified based on a semi-automated strategy by computing the total change in squared amplitude spectrum. A frequency weighted variable feedback gain optimization algorithm is constructed by minimizing complex power flow. Also, an adaptive gain selection scheme with upper bound to the actuator input voltage in implemented. The proposed model is computationally much faster and smaller in size compared to conventional MIMO state space models. Case studies on a composite cantilever beam and a three member network are carried out to illustrate the efficiency of the model.

  5. On the Relationship Between Site Geology and the Distribution of Surface Regolith Compositions at the Apollo Sites

    NASA Technical Reports Server (NTRS)

    Korotev, Randy L.

    2000-01-01

    Some considerations are discussed on how information on site geology can be obtained from the distribution of data points on 2-element plots of composition of lunar regolith samples collected along a traverse.

  6. Composite Life Cycle of Maritime Tropical Mesoscale Convective Systems in Scatterometer and Microwave Satellite Observations

    E-print Network

    Mapes, Brian

    and Microwave Satellite Observations BRIAN MAPES Rosenstiel School of Marine and Atmospheric Sciences life cycle-- from precursors to initiation to maturity to decay and aftereffects--is especially hard observations. Aircraft cannot be tar- geted to initiation events because these are not well forecast

  7. Life Cycle Modeling of Concrete Bridge Design: Comparison of Engineered Cementitious Composite Link Slabs

    E-print Network

    Lepech, Michael D.

    of approximately 260 million t of concrete annually in the United States Kelly 1998 . This material flow represents of the national highway and road system. While United States consumption is significant, glo- bal construction performance: 40% less life cycle energy consumption, 50% less solid waste generation, and 38% less raw

  8. A requirement for reduced pressure and modified atmosphere composition in lunar and martian biological life support systems

    NASA Astrophysics Data System (ADS)

    Dixon, Mike; Stasiak, Michael; Wehkamp, Cara Ann; Lawson, Jamie

    The Controlled Environment Systems Research Facility at the PlaceTypeUniversity of Place- NameGuelph (country-regionplaceCanada) represents an extensive collection of variable pressure plant growth chambers devoted to the study of biological systems including plants and microbes, in life support roles for space exploration. To simplify engineering requirements for plant growth structures on the Moon or Mars, lower pressures are required in order to reduce mass and decrease atmospheric leakage. Few facilities exist that can provide low pressure plant growth capabilities coupled with complete control over temperature, vapour pressure deficit (humidity), gas composition, nutrient delivery, and pressure. The Controlled Environment Systems Research Facility maintains five canopy-scale hypobaric plant growth chambers with capabilities ideally suited for low pressure advanced life support research. System performance evaluations during low pressure experiments on radish (Raphanus sativa L. cv. Cherry Bomb II) have demonstrated temperature control of +/- 0.5 ° C, vapour pressure deficit control of +/- 0.5 mb, CO2 injection control of +/- 20 ` ?mol mol-1 , and leakage rates of less than 1% per day. Keywords: hypobaric, plant growth chamber, advanced life support, controlled environment, low pressure, atmospheric control

  9. Chemosymbiotic species from the Gulf of Cadiz (NE Atlantic): distribution, life styles and nutritional patterns

    NASA Astrophysics Data System (ADS)

    Rodrigues, C. F.; Hilário, A.; Cunha, M. R.

    2012-12-01

    Previous work in the mud volcanoes from the Gulf of Cadiz revealed a high number of chemosymbiotic species, namely bivalves and siboglinid polychaetes. In this study we give an overview of the distribution and life styles of those species in the Gulf of Cadiz, determine the role of autotrophic symbionts in the nutrition of selected species using stable isotope analyses (?13C, ?15N and ?34S) and investigate the intra-specific variation of isotope signatures within and between study sites. Twenty siboglinid and nine bivalve chemosymbiotic species have been identified and were found living in fifteen mud volcanoes during our studies. Solemyids bivalves and tubeworms of the genus Siboglinum are the most widespread, whereas other species were found in a single mud volcano (e.g. "Bathymodiolus" mauritanicus) or restricted to deeper mud volcanoes (e.g. Polybrachia sp., Lamelisabella denticulata). Species distribution suggests that different species may adjust their position within the sediment according to their particular needs and intensity and variability of the chemical substrata supply. Isotopic values found for selected species are in accordance with values found in other studies, with thiotrophy as the dominant nutritional pathway, and with methanotrophy and mixotrophy emerging as secondary strategies. The heterogeneity in terms of nutrient sources (expressed in the high variance of nitrogen and sulphur values) and the ability to exploit different resources by the different species may explain the high diversity of chemosymbiotic species found in the Gulf of Cadiz. This study increases the knowledge of the chemosymbiotic species in the Gulf of Cadiz, highlight the relevance of seep chemoautolithotrophic production in this area and provide a starting point for future trophic ecology studies.

  10. Evaluation of light transmission and distribution materials for Lunar and Martian bioregenerative life support.

    PubMed

    Cuello, J L; Sadler, P; Jack, D; Ono, E; Jordan, K A

    1998-01-01

    The materials that were selected and evaluated in this study in the context of bioregenerative advanced life support included polymer optical cables, for transmission of photosynthetic photon flux (PPF), and light pipe, woven optical pad and light-emitting fiber (LEF) for PPF distribution. All materials exhibited significant fidelity in transmitting the spectral characteristics of the artificial lluminator's Xenon-Metal Halide lamp. The PPF attenuation values for the polymer cables EL-200, EL-300, EL-400, and EL-500 were not significantly distinguishable from one another nor from that of the fused-silica cable of 0.34 dB/m. With the exception of EL-100 and EL-700, which had significantly lower PPF transmission efficiencies of 54.9%/m and 66.6%/m, respectively, all the other polymer cables had PPF transmission efficiencies of over 85%/m which, except for EL-300, were not significantly different from one another nor from that of the fused-silica cable of 93.2%/m. The highest PPF output efficiency achieved for the 7.1-cm light pipe 14.7%, for its maximum pipe length of 100 cm. At a constant pipe length of 50 cm, the PPF output efficiency of the 10-cm light pipe of 0.71% was significantly lower than that of the 7.1-cm light pipe of 10.54%. The PPF output for the woven optical pad was determined to be 36.3%. The PPF output efficiency for the LEF without the optic fastener was determined to be 27.1%, whereas that for the LEF with the optic fastener was 50.3%, that is, the maximum value of PPF output efficiency in the study. The polymer optical cables, light pipe, woven optical pad, and LEF exhibited significant regularity and symmetry in their PPF output spatial distributions. PMID:11871446

  11. Recent advances in ionic polymer conductor composite materials as distributed nanosensors, nanoactuators, and artificial muscles (Invited Paper)

    Microsoft Academic Search

    Mohsen Shahinpoor

    2005-01-01

    Recent advances in ionic polymer conductor composites (IPCC) and ionic polymer metal composites (IPMC) as biomimetic distributed nanosensors, nanoactuators, nanotransducers and artificial muscles are briefly discussed in this paper. These advances include brief reproduction of some of these advances that appeared in a new book and a recent set of 4 review articles published in the International Journal of Smart

  12. Effects of diet macronutrient composition on body composition and fat distribution during weight maintenance and weight loss

    PubMed Central

    Goss, Amy M.; Goree, Laura Lee; Ellis, Amy C.; Chandler-Laney, Paula C.; Casazza, Krista; Lockhart, Mark E.; Gower, Barbara A.

    2012-01-01

    Qualitative aspects of diet may affect body composition and propensity for weight gain or loss. We tested the hypothesis that consumption of a relatively low glycemic load (GL) diet would reduce total and visceral adipose tissue under both eucaloric and hypocaloric conditions. Participants were 69 healthy overweight men and women. Body composition was assessed by DXA and fat distribution by CT scan at baseline, after 8 weeks of a eucaloric diet intervention, and after 8 weeks of a hypocaloric (1000 kcal/d deficit) diet intervention. Participants were provided all food for both phases, and randomized to either a low GL diet (?45 points per 1000 kcal; n=40) or high GL diet (>75 points per 1000 kcal, n=29). After the eucaloric phase, participants who consumed the low GL diet had 11% less intra-abdominal fat (IAAT) than those who consumed the high GL diet (P<0.05, adjusted for total fat mass and baseline IAAT). Participants lost an average of 5.8 kg during the hypocaloric phase, with no differences in the amount of weight loss with diet assignment (P=0.39). Following weight loss, participants who consumed the low GL diet had 4.4% less total fat mass than those who consumed the high GL diet (P<0.05, adjusted for lean mass and baseline fat mass). Consumption of a relatively low GL diet may affect energy partitioning, both inducing reduction in IAAT independent of weight change, and enhancing loss of fat relative to lean mass during weight loss. PMID:23671029

  13. The Chemical Composition and Nitrogen Distribution of Chinese Yak (Maiwa) Milk

    PubMed Central

    Li, Haimei; Ma, Ying; Li, Qiming; Wang, Jiaqi; Cheng, Jinju; Xue, Jun; Shi, John

    2011-01-01

    The paper surveyed the chemical composition and nitrogen distribution of Maiwa yak milk, and compared the results with reference composition of cow milk. Compared to cow milk, yak milk was richer in protein (especially whey protein), essential amino acids, fat, lactose and minerals (except phosphorus). The contents of some nutrients (total protein, lactose, essential amino acids and casein) were higher in the warm season than in the cold season. Higher ratios of total essential amino acids/total amino acids (TEAA/TAA) and total essential amino acids/total non essential amino acids (TEAA/TNEAA) were found in the yak milk from the warm season. However its annual average ratio of EAA/TAA and that of EAA/NEAA were similar to those of cow milk. Yak milk was rich in calcium and iron (p < 0.05), and thus may serve as a nutritional ingredient with a potential application in industrial processing. PMID:21954332

  14. A study of the charged ice grains in the Enceladus plume with a composite size distribution

    NASA Astrophysics Data System (ADS)

    Dong, Y.; Hill, T. W.

    2013-12-01

    We study the negatively charged ice grains in the Enceladus plume ranging from nanometer to micrometer in size based on Cassini's multiple instrument observations. We have constructed a composite size distribution by combining the CAPS nanograin size distributions (Hill et al., 2012 JGR) and the CDA dust power-law size distribution (Kempf et al., 2008 Icarus). We also study the charging of the ice grains using RPWS-LP data (Morooka et al., 2011 JGR). E3 and E5 CDA data are not available, but RPWS detected impacts of micron sized dust grains with the same power law size distribution (Ye et al., 2012 AGU meeting). Our size distribution formula is fitted with E3 and E5 CAPS and RPWS data, and constrained with the total dust charge density inferred from the RPWS-LP cold plasma data. The fitting with E17 and E18 CAPS nanograin data (Tokar et al., 2012 AGU meeting) and RPWS dust data (Ye et al., 2013 MAPS workshop) will also be discussed. Based on the charge per grain and the size distribution, the densities, source rate, motion, and currents of the ice grains can be calculated. Our size distribution implies that the grains ~2-20 nm dominate in both charge density and number density. But the mass density is very sensitive to the larger grains. We discuss the mass densities and source rates with different size distribution parameters, and compare with the water vapor plume. We study the trajectories of the charged ice grains in both Enceladus and Saturn frames, and calculate the dust currents from their motion. We find that the total dust pickup current at Enceladus is ?10^5 A. We will also discuss the ion and dust current systems and resulting magnetic perturbations near the moon.

  15. A Fatigue Damage Parameter for Life Assessment of Off-axis Unidirectional GRP Composites

    Microsoft Academic Search

    A. Varvani-Farahani; H. Haftchenari; M. Panbechi

    2006-01-01

    The present study develops a fatigue damage parameter to assess the fatigue damage of unidirectional glass fiber reinforced plastic (GRP) composites. The proposed parameter is based on the physics and the mechanism of fatigue cracking within three damage regions of matrix (I), fiber-matrix interface (II), and fiber (III) in these materials as the number of cycles progresses. In region I,

  16. Somatic Maintenance Resources in the Honeybee Worker Fat Body Are Distributed to Withstand the Most Life-Threatening Challenges at Each Life Stage

    PubMed Central

    Seehuus, Siri-Christine; Taylor, Simon; Petersen, Kjell; Aamodt, Randi M.

    2013-01-01

    In a global transcriptome analysis of three natural and three manipulated honeybee worker phenotypes at different ages, we have investigated the distribution of investment in somatic maintenance of the fat body. Gene expression is modulated so that the bees are able to resist the most life-threatening challenges at the actual life stage. Different modes of maintenance and repair are regulated, apparently to meet the environmental challenges most detrimental to survival and reproductive potential for the hive. We observed a broad down-regulation of genomic and cellular maintenance in the short-lived foragers and nurse bees compared to the long-lived winter bees. Our results show that survival and reproduction of the entire hive is given priority over the individual bees, hence supporting the idea of the honeybee society as a superorganism. Our results also fit the disposable soma theory of aging. PMID:23940531

  17. The small volume particle microsampler (SVPM): a new approach to particle size distribution and composition

    NASA Astrophysics Data System (ADS)

    Archambault, Marie-Claude; Grant, Jon; Hatcher, Annamarie

    2001-10-01

    The characterization of trophically and geochemically important suspended particulate matter (SPM) has traditionally relied on bottle sampling and subsequent analysis with Coulter Multisizers and other instruments, which are not sufficient in preserving the in situ size, shape and composition of aggregated particles. The small volume particle microsampler (SVPM) is a sampling device that captures individual particles on filters with minimal disturbance for microscope image analysis of size distribution and composition. Sand grains, microalga ( Dunaliella tertiolecta) and laboratory cultivated flocs were used to test the SVPM's ability to determine particle size. For statistical analysis of the SVPM's capabilities, sand grain and algal size distribution, calculated as equivalent spherical diameter (ESD), were compared to Multisizer data while video images provided a comparison for the flocs. Non-aggregated sand particles sampled by the SVPM showed a size distribution that was similar to that of the Multisizer. Aggregated D. tertiolecta flocs were broken up by the Multisizer, and SVPM data indicated a significantly greater mean ESD. The SVPM showed significantly smaller mean ESDs than the video images because of the higher resolution of the sampler for small particles. In terms of particle concentration, the microsampler measured values similar to those of the Multisizer and video camera. The most important feature of the SVPM is its ability to capture aggregates for the analysis of composition, by histological stains or other means. The SVPM is an alternative method of sampling that is more effective in preserving aggregates for laboratory analyses and is less complicated and expensive than in situ optical sampling techniques, especially in documenting the lower end of the particle size spectrum.

  18. Distributed sensing of Composite Over-wrapped Pressure Vessels using Fiber-Bragg Gratings

    NASA Technical Reports Server (NTRS)

    Grant, Joseph

    2005-01-01

    The increasing use of advanced composite materials in the wide range of applications including Space Structures is a great impetus to the development of smart materials. These materials offer a wide range of possibilities within the space program. But before they can be reliably incorporated into space flight applications, additional understanding is required in the area of damage tolerance of these materials. Efforts to enhance our understanding of failure modes, mechanical properties, long and short term environmental effects, cyclic damage accumulation and residual strength are needed. Thus we have employed the use of fiber optical sensors which offers an excellent opportunity exploit these materials through monitoring and characterizing their mechanical properties and thus the integrity of structures made from such materials during their life cycle. Use of these optical innovations provides an insight into structures that have not been available in the past, as well as the technology available to provide real time health monitoring throughout its life cycle. The embedded fiber optical sensor shows a clearly detectable sensitivity to changes in the near strain and stress fields of the host structure promoted by mechanical or thermal loading or, in certain conditions, structural damage. The last ten years have seen a large increase in the use of FBG based monitoring systems in a broad range of applications. Fiber Bragg gratings are use to monitor the structural properties of composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in composite structures. The fiber Bragg sensors are both embedded within the composite laminates and bonded to the surface of the vessel with varying orientations with respect to the carbon fiber in the epoxy matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 4400 psi. This is done at both ambient and cryogenic temperatures using water and liquid nitrogen. The recorded response is compared with the response from conventional strain gauge also present on the vessel. Additionally, several vessels were tested that had been damaged to simulate different type of events, such as cut tow, delimitation and impact damage.

  19. Fatigue, fracture, and life prediction criteria for composite materials in magnets

    SciTech Connect

    Wong, F.M.G.

    1990-06-01

    An explosively-bonded copper/Inconel 718/copper laminate conductor was proposed to withstand the severe face compression stresses in the central core of the Alcator C-MOD tokamak toroidal field (TF) magnet. Due to the severe duty of the TF magnet, it is critical that an accurate estimate of useful life be determined. As part of the effort to formulate an appropriate life prediction, fatigue crack growth experiments were performed on the laminate as well as its components. Metallographic evaluation of the laminate interface revealed many shear bands in the Inconel 718. Shear bands and shear band cracks were produced in the Inconel 718 as a result of the explosion bonding process. These shear bands were shown to have a detrimental effect on the crack growth behavior of the laminate, by significantly reducing the load carrying capability of the reinforcement layer and providing for easy crack propagation paths. Fatigue crack growth rate was found not only to be dependent on temperature but also on orientation. Fatigue cracks grew faster in directions which contained shear bands in the plane of the propagating crack. Fractography showed crack advancement by fatigue cracking in the Inconel 718 and ductile tearing of the copper at the interface. However, further away from the interfaces, the copper exhibited fatigue striations indicating that cracks were now propagating by fatigue. Laminate life prediction results showed a strong dependence on shear band orientation, and exhibited little variation between room temperature and 77{degree}K. Predicted life of this laminate was lower when the crack propagation was along a shear band than when crack propagation was across the shear bands. Shear bands appear to have a dominating effect on crack growth behavior.

  20. Exobiology, the study of the origin, evolution and distribution of life within the context of cosmic evolution: a review.

    PubMed

    Horneck, G

    1995-01-01

    The primary goal of exobiological research is to reach a better understanding of the processes leading to the origin, evolution and distribution of life on Earth or elsewhere in the universe. In this endeavour, scientists from a wide variety of disciplines are involved, such as astronomy, planetary research, organic chemistry, palaeontology and the various subdisciplines of biology including microbial ecology and molecular biology. Space technology plays an important part by offering the opportunity for exploring our solar system, for collecting extraterrestrial samples, and for utilizing the peculiar environment of space as a tool. Exobiological activities include comparison of the overall pattern of chemical evolution of potential precursors of life, in the interstellar medium, and on the planets and small bodies of our solar system; tracing the history of life on Earth back to its roots; deciphering the environments of the planets in our solar system and of their satellites, throughout their history, with regard to their habitability; searching for other planetary systems in our Galaxy and for signals of extraterrestrial civilizations; testing the impact of space environment on survivability of resistant life forms. This evolutionary approach towards understanding the phenomenon of life in the context of cosmic evolution may eventually contribute to a better understanding of the processes regulating the interactions of life with its environment on Earth. PMID:11538433

  1. Modified oleic cottonseeds show altered content, composition and tissue-specific distribution of triacylglycerol molecular species.

    PubMed

    Horn, Patrick J; Sturtevant, Drew; Chapman, Kent D

    2014-01-01

    Targeted increases in monounsaturated (oleic acid) fatty acid content of refined cottonseed oil could support improved human nutrition and cardiovascular health. Genetic modifications of cottonseed fatty acid composition have been accomplished using several different molecular strategies. Modification of oleic acid content in cottonseed embryos using a dominant-negative protein approach, while successful in effecting change in the desired fatty acid composition, resulted in reduced oil content and seed viability. Here these changes in fatty acid composition were associated with changes in dominant molecular species of triacylglycerols (TAGs) and their spatial distributions within embryo tissues. A combination of mass spectrometry (MS)-based lipidomics approaches, including MS imaging of seed cryo-sections, revealed that cotton embryos expressing a non-functional allele of a Brassica napus delta-12 desaturase showed altered accumulation of TAG species, especially within cotyledonary tissues. While lipid analysis of seed extracts could demonstrate detailed quantitative changes in TAG species in transgenics, the spatial contribution of metabolite compartmentation could only be visualized by MS imaging. Our results suggest tissue-specific differences in TAG biosynthetic pathways within cotton embryos, and indicate the importance of considering the location of metabolites in tissues in addition to their identification and quantification when developing a detailed view of cellular metabolism. PMID:23973433

  2. Central Appalachian basin natural gas database: distribution, composition, and origin of natural gases

    USGS Publications Warehouse

    Román Colón, Yomayra A.; Ruppert, Leslie F.

    2015-01-01

    The U.S. Geological Survey (USGS) has compiled a database consisting of three worksheets of central Appalachian basin natural gas analyses and isotopic compositions from published and unpublished sources of 1,282 gas samples from Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The database includes field and reservoir names, well and State identification number, selected geologic reservoir properties, and the composition of natural gases (methane; ethane; propane; butane, iso-butane [i-butane]; normal butane [n-butane]; iso-pentane [i-pentane]; normal pentane [n-pentane]; cyclohexane, and hexanes). In the first worksheet, location and American Petroleum Institute (API) numbers from public or published sources are provided for 1,231 of the 1,282 gas samples. A second worksheet of 186 gas samples was compiled from published sources and augmented with public location information and contains carbon, hydrogen, and nitrogen isotopic measurements of natural gas. The third worksheet is a key for all abbreviations in the database. The database can be used to better constrain the stratigraphic distribution, composition, and origin of natural gas in the central Appalachian basin.

  3. Composition, diversity and distribution of microbenthos across the intertidal zones of Ryazhkov Island (the White Sea).

    PubMed

    Azovsky, Andrey; Saburova, Maria; Tikhonenkov, Denis; Khazanova, Ksenya; Esaulov, Anton; Mazei, Yuri

    2013-11-01

    The composition and distribution of the main unicellular eukaryotic groups (diatom algae, ciliates, dinoflagellates (DF), other phototrophic (PF) and heterotrophic flagellates (HF)) were investigated in sandy sediments at five stations allocated across the tidal sheltered beach of the White Sea. Overall, 75 diatoms, 98 ciliates, 16 DF, 3 PF and 34 HF species were identified; some are new records for the White Sea. Common species for each group are illustrated. Diatoms and ciliates showed high alpha-diversity (species richness per sample), whereas flagellates were characterized by high beta-diversity (species turnover across the intertidal flat). Each group demonstrated its own spatial pattern that was best matched with its own subset of abiotic variables, reflecting group-specific responses to environmental gradients. Species richness increased from the upper intertidal zone seaward for ciliates but decreased for HF, whereas autotrophs showed a relatively uniform pattern with a slight peak at the mid-intertidal zone. Across the littoral zone, all groups showed distinct compositional changes; however, the position of the boundary between "upper" and "lower" intertidal communities varied among groups. Most of the species found at Ryazhkov Island are known from many other regions worldwide, indicating a wide geographic distribution of microbial eukaryotic species. PMID:23871644

  4. Temporal Variations in the Abundance and Composition of Biofilm Communities Colonizing Drinking Water Distribution Pipes

    PubMed Central

    Kelly, John J.; Minalt, Nicole; Culotti, Alessandro; Pryor, Marsha; Packman, Aaron

    2014-01-01

    Pipes that transport drinking water through municipal drinking water distribution systems (DWDS) are challenging habitats for microorganisms. Distribution networks are dark, oligotrophic and contain disinfectants; yet microbes frequently form biofilms attached to interior surfaces of DWDS pipes. Relatively little is known about the species composition and ecology of these biofilms due to challenges associated with sample acquisition from actual DWDS. We report the analysis of biofilms from five pipe samples collected from the same region of a DWDS in Florida, USA, over an 18 month period between February 2011 and August 2012. The bacterial abundance and composition of biofilm communities within the pipes were analyzed by heterotrophic plate counts and tag pyrosequencing of 16S rRNA genes, respectively. Bacterial numbers varied significantly based on sampling date and were positively correlated with water temperature and the concentration of nitrate. However, there was no significant relationship between the concentration of disinfectant in the drinking water (monochloramine) and the abundance of bacteria within the biofilms. Pyrosequencing analysis identified a total of 677 operational taxonomic units (OTUs) (3% distance) within the biofilms but indicated that community diversity was low and varied between sampling dates. Biofilms were dominated by a few taxa, specifically Methylomonas, Acinetobacter, Mycobacterium, and Xanthomonadaceae, and the dominant taxa within the biofilms varied dramatically between sampling times. The drinking water characteristics most strongly correlated with bacterial community composition were concentrations of nitrate, ammonium, total chlorine and monochloramine, as well as alkalinity and hardness. Biofilms from the sampling date with the highest nitrate concentration were the most abundant and diverse and were dominated by Acinetobacter. PMID:24858562

  5. A meta-analysis of the genomic and transcriptomic composition of complex life

    PubMed Central

    Liu, Ganqiang; Mattick, John S.; Taft, Ryan J.

    2013-01-01

    It is now clear that animal genomes are predominantly non-protein-coding, and that these sequences encode a wide array of RNA transcripts and other regulatory elements that are fundamental to the development of complex life. We have previously argued that the proportion of an animal genome that is non-protein-coding DNA (ncDNA) correlates well with its apparent biological complexity. Here we extend on that work and, using data from a total of 1,627 prokaryotic and 153 eukaryotic complete and annotated genomes, show that the proportion of ncDNA per haploid genome is significantly positively correlated with a previously published proxy of biological complexity, the number of distinct cell types. This is in contrast to the amount of the genome that encodes proteins, which we show is essentially unchanged across Metazoa. Furthermore, using a total of 179 RNA-seq data sets from nematode (47), fruit fly (72), zebrafish (20) and human (42), we show, consistent with other recent reports, that the vast majority of ncDNA in animals is transcribed. This includes more than 60 human loci previously considered “gene deserts,” many of which are expressed tissue-specifically and associated with previously reported GWAS SNPs. These results suggest that ncDNA, and the ncRNAs encoded within it, may be intimately involved in the evolution, maintenance and development of complex life. PMID:23759593

  6. Species composition and bathymetric distribution of gorgonians (Anthozoa: Octocorallia) on the Southern Mexican Pacific coast.

    PubMed

    Abeytia, Rosalinda; Guzmán, Hector M; Breedy, Odalisca

    2013-09-01

    Gorgonians are important components of coastal ecosystems, as they provide niches, natural compounds with medical applications and are used as bioindicators. Species composition and assemblage structure of gorgonians (Anthozoa: Octocorallia) were studied along a bathymetric profile in the Southern Mexican Pacific coast. Species composition was based on specimens collected within a depth range of 0-70 m in 15 sites. The relative abundance of species was determined in six sites at four depths (5, 10, 20 and 25 m) using three 10 m2 transects at each depth level. Twenty-seven species of gorgonians belonging to six genera and three families were registered. The species composition varied with depth: 11 species were distributed between 0-25m depth, while 17 species were found between 40-70 m depth interval. The shallow zone is characterized by a relatively large abundance of gorgonians, dominated by colonies of Leptogorgia cuspidata and L. ena. In contrast, the deepest zone was characterized by relatively low abundance of gorgonians, dominated by L. alba, the only species observed in both depth intervals. The similarity analysis showed differences in the composition and abundance of species by depth and site, suggesting that the main factor in determining the assemblage structure is depth. Results of this study suggest that the highest richness of gorgonian species in the study area may be located at depths of 40-70 m, whereas the highest abundances are found between 5 and 10 m depth. This study represents a contribution to the poorly known eastern Pacific gorgonian biota. PMID:24027914

  7. Aerobic versus resistance training effects on health-related quality of life, body composition, and function of older adults.

    PubMed

    Canuto Wanderley, Flávia Accioly; Oliveira, Nórton Luis; Marques, Elisa; Moreira, Pedro; Oliveira, José; Carvalho, Joana

    2015-04-01

    This study aimed to investigate the effects of training on health-related quality of life (HRQoL), body composition, and function in older adults. Fifty participants were randomized into aerobic training (AT--70%-80% HR reserve), resistance training (RT--80% 1RM), or controls. They had HRQoL, body composition, and function assessed before and after 8 months. Training groups reduced body fat, increased performance in the stair ascent, 8-ft up-and-go and sit-to-stand five-times tests, and improved their physical component score (PCS; p ? .03). AT increased performance in the 6MWT test, and improved general and mental health (MH) domains when compared to controls (p < .01). Finally, changes in stair ascent were associated with changes in bodily pain, MH, and mental component score (p ? .04), while changes in handgrip strength were associated with changes in physical role and MH (p = .03). AT and RT were effective interventions for decreasing body fat and improving functionality and the PCS in older adults. PMID:24652860

  8. Effects of Life History Strategy on Fish Distribution and Use of Estuarine Salt Marsh and Shallow-Water Flat Habitats

    Microsoft Academic Search

    David L. Meyer; Martin H. Posey

    2009-01-01

    To assess the potential for habitat isolation effects on estuarine nekton, we used two species with different dispersal abilities\\u000a and life history strategies, mummichog (Fundulus heteroclitus) and pinfish (Lagodon rhomboides) to examine: (1) distribution trends among estuarine shallow-water flat and various intertidal salt marsh habitats and (2)\\u000a the influence of salt marsh habitat size and isolation. Collections were conducted using

  9. Failure models for textile composites

    NASA Technical Reports Server (NTRS)

    Cox, Brian

    1995-01-01

    The goals of this investigation were to: (1) identify mechanisms of failure and determine how the architecture of reinforcing fibers in 3D woven composites controlled stiffness, strength, strain to failure, work of fracture, notch sensitivity, and fatigue life; and (2) to model composite stiffness, strength, and fatigue life. A total of 11 different angle and orthogonal interlock woven composites were examined. Composite properties depended on the weave architecture, the tow size, and the spatial distributions and strength of geometrical flaws. Simple models were developed for elastic properties, strength, and fatigue life. A more complicated stochastic model, called the 'Binary Model,' was developed for damage tolerance and ultimate failure. These 3D woven composites possessed an extraordinary combination of strength, damage tolerance, and notch insensitivity.

  10. [Floristic composition and distribution of the Andean subtropical riparian forests of Lules River, Tucuman, Argentina].

    PubMed

    Sirombra, Martín G; Mesa, Leticia M

    2010-03-01

    We studied the floristic composition and distribution of the riparian forest of two hydrographical systems in a subtropical Andean region. Using uni and multivariate techniques, we tested the hypotheses that a differentiable riparian forest exists, composed by native vegetation typical of the Yungas phytogeographical province, and that the distribution of vegetation varied significantly with geomorphologic characteristics. Parallel transects along the water courses were used to collect presence-absence data of vegetation in eleven sites. Detrended Correspondence Analysis defined a group of common riparian species for the studied area (Solanum riparium, Phenax laevigatus, Tipuana tipu, Cestrum parqui, Carica quercifolia, Acacia macracantha, Celtis iguanaea, Juglans australis, Pisoniella arborescens, Baccharis salicifolia, Cinnamomum porphyrium and Eugenia uniflora) and identified two reference sites. The distribution of the riparian vegetation varied significantly with the geomorphic characteristics along the studied sites. Riparian habitats were composed by native and exotic species. A distinct riparian flora, different in structure and function from adjacent terrestrial vegetation, could not be identified. Riparian species were similar to the adjacent terrestrial strata. These species would not be limited by the proximity to the river. Anthropogenic impacts were important factors regulating the introduction and increase of exotic vegetation. The lack of regulation of some activities in the zone could cause serious problems in the integrity of this ecosystem. PMID:20411737

  11. Composition.

    ERIC Educational Resources Information Center

    Nemanich, Donald, Ed.

    1974-01-01

    The articles in this special issue of the "Illinois English Bulletin" concern the state of composition instruction at the secondary and college levels. The titles and authors are "Monologues or Dialogues? A Plea for Literacy" by Dr. Alfred J. Lindsey, "Teaching Composition: Curiouser and Curiouser" by Denny Brandon, and "Teaching Writing to High…

  12. Pelagic cephalopods from eastern Australia: species composition, horizontal and vertical distribution determined from the diets of pelagic fishes

    Microsoft Academic Search

    Matt Lansdell; Jock Young

    2007-01-01

    The distribution and relative biomass of cephalopods from pelagic waters off eastern Australia was examined between 1997 and\\u000a 2004 from stomach contents of swordfish, yellowfin tuna and dolphinfish taken in the domestic longline fishery. A total of\\u000a 38 taxa from 19 families were identified. Comparison of the species composition of the three predators indicated pronounced\\u000a differences in cephalopod species composition.

  13. Friction Stir Processing of Al-TiB2 In Situ Composite: Effect on Particle Distribution, Microstructure and Properties

    NASA Astrophysics Data System (ADS)

    Yadav, Devinder; Bauri, Ranjit

    2015-03-01

    Aluminum-based in situ composites suffer from the age-old issue of particle segregation along the grain boundaries after casting. In the present study, friction stir processing (FSP) was employed as a secondary process to improve the distribution of in situ formed TiB2 particles in Al-based composite. All the agglomerates of TiB2 were broken, and uniform distribution of particles was achieved after double-pass FSP. Also, FSP removed the casting defects and caused significant grain refinement of the Al matrix. The microstructure was characterized by equiaxed fine grains with average size of 3 µm and narrow grain size distribution. The microstructural refinements and homogenization after FSP not only enhanced the strength but also improved the ductility of the as-cast composite.

  14. Recent advances in ionic polymer conductor composite materials as distributed nanosensors, nanoactuators, and artificial muscles (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Shahinpoor, Mohsen

    2005-05-01

    Recent advances in ionic polymer conductor composites (IPCC) and ionic polymer metal composites (IPMC) as biomimetic distributed nanosensors, nanoactuators, nanotransducers and artificial muscles are briefly discussed in this paper. These advances include brief reproduction of some of these advances that appeared in a new book and a recent set of 4 review articles published in the International Journal of Smart Materials and Structures, advances in manufacturing, force optimization, modeling and simulation and new products developed by Environmental Robots Incorporated, as well as numerous potential applications using Ionic Polymer-Metal Composites (IPMC's) as distributed nanosensors, nanotransducers, nanoactuators and artificial muscles. It is certainly clear that the extent of applications of IPCC's and IPMC's go beyond the scope of this paper or the space allocated to this paper. However, this paper will present the breadth and the depth of all such applications of IPCC's and IPMC's as biomimetic robotic distributed nanosensors, nanoactuators, nanotransducers and artificial/synthetic muscles.

  15. Application of Distribution Transformer Thermal Life Models to Electrified Vehicle Charging Loads Using Monte-Carlo Method: Preprint

    SciTech Connect

    Kuss, M.; Markel, T.; Kramer, W.

    2011-01-01

    Concentrated purchasing patterns of plug-in vehicles may result in localized distribution transformer overload scenarios. Prolonged periods of transformer overloading causes service life decrements, and in worst-case scenarios, results in tripped thermal relays and residential service outages. This analysis will review distribution transformer load models developed in the IEC 60076 standard, and apply the model to a neighborhood with plug-in hybrids. Residential distribution transformers are sized such that night-time cooling provides thermal recovery from heavy load conditions during the daytime utility peak. It is expected that PHEVs will primarily be charged at night in a residential setting. If not managed properly, some distribution transformers could become overloaded, leading to a reduction in transformer life expectancy, thus increasing costs to utilities and consumers. A Monte-Carlo scheme simulated each day of the year, evaluating 100 load scenarios as it swept through the following variables: number of vehicle per transformer, transformer size, and charging rate. A general method for determining expected transformer aging rate will be developed, based on the energy needs of plug-in vehicles loading a residential transformer.

  16. Interfacial shear stress distribution in model composites. I - A Kevlar 49 fibre in an epoxy matrix

    SciTech Connect

    Jahankhani, H.; Galiotis, C. (Queen Mary and Westfield College, London (England))

    1991-05-01

    The technique of Laser Raman Spectroscopy has been applied in the study of aramid fibers, such as Kevlar 49, and aramid/epoxy interfaces. A linear relationship has been found between Raman frequencies and strain upon loading a single Kevlar 49 filament in air. Model composites of single Kevlar 49 fibers embedded in epoxy resins have been fabricated and subjected to various degrees of mechanical deformation. The transfer lengths for reinforcement have been measured at various levels of applied tensile load and the dependence of transfer length upon applied matrix strain has been established. Finally, by balancing the tensile and the shear forces acting along the interface, the interfacial shear stress (ISS) distribution along the embedded fiber was obtained. 52 refs.

  17. Spatial distribution and species composition of small pelagic fishes in the Gulf of California.

    PubMed

    Lanz, Edgar; Nevárez-Martínez, Manuel O; López-Martínez, Juana; Dworak, Juan A

    2008-06-01

    Traditional regionalization methods in fisheries based on provinces or major fishing areas, includes large and arbitrary grids in which basic statistics or inferences on distribution or abundance are made. We describe a method for regionalization and analysis of fishing activities for small pelagic fisheries in the Gulf of California based on spatial patterns of landing and catch data in a Geographic Information System (GIS) environment. A fisheries database from logbooks with spatial attributes from October 2002 to June 2007 was analyzed. Landings and catching data were transformed to a Weighted Region Index (WRI) by using fuzzy logic operators. The WRI revealed fishing action centers characterized by areas with the highest WRI values, and a hierarchy for the relative importance of the regions was established. Guaymas, Desemboque de Caborca, Isla Patos, and Bahia San Rafael they were the most prominent ones. An analysis of the relative frequency of species composition showed that the Pacific sardine had an over 80 % abundance in the midriff islands, and remained as the most important in the upper gulf regions, while in the central part of the gulf, relative abundances of Pacific sardine and Northern anchovy were more balanced. Relative abundance of mackerel was significantly larger around Isla Patos than in any other place. Guaymas had the largest relative composition of Northern anchovy and the lowest values for Pacific sardine. Desemboque de Caborca showed the largest homogeneity in species relative composition. It is important to highlight that this results come from in situ data, while the results previously reported come from landing statistics by port. Therefore, the present method acknowledges the spatial differences of species by regions, additional to the traditional time series analysis. PMID:19256429

  18. Fatigue Life Prediction of Carbon Fiber-Reinforced Ceramic-Matrix Composites at Room and Elevated Temperatures. Part I: Experimental Analysis

    NASA Astrophysics Data System (ADS)

    Longbiao, Li

    2015-05-01

    This paper presents an experimental analysis on the fatigue behavior in C/SiC ceramic-matrix composites (CMCs) with different fiber preforms, i.e., unidirectional, cross-ply and 2.5D woven, at room and elevated temperatures in air atmosphere. The experimental fatigue life S - N curves of C/SiC composites corresponding to different stress levels and test conditions have been obtained. The damage evolution processes under fatigue loading have been analyzed using fatigue hysteresis modulus and fatigue hysteresis loss energy. By comparing the experimental fatigue hysteresis loss energy with theoretical computational values, the interface shear stress corresponding to different peak stress, fiber preforms and test conditions have been estimated. It was found that the degradation of interface shear stress and fibres strength caused by oxidation markedly decreases the fatigue life of C/SiC composites at elevated temperature.

  19. Decompression vs. Decomposition: Distribution, Amount, and Gas Composition of Bubbles in Stranded Marine Mammals.

    PubMed

    de Quirós, Yara Bernaldo; González-Diaz, Oscar; Arbelo, Manuel; Sierra, Eva; Sacchini, Simona; Fernández, Antonio

    2012-01-01

    Gas embolic lesions linked to military sonar have been described in stranded cetaceans including beaked whales. These descriptions suggest that gas bubbles in marine mammal tissues may be more common than previously thought. In this study we have analyzed gas amount (by gas score) and gas composition within different decomposition codes using a standardized methodology. This broad study has allowed us to explore species-specific variability in bubble prevalence, amount, distribution, and composition, as well as masking of bubble content by putrefaction gases. Bubbles detected within the cardiovascular system and other tissues related to both pre- and port-mortem processes are a common finding on necropsy of stranded cetaceans. To minimize masking by putrefaction gases, necropsy, and gas sampling must be performed as soon as possible. Before 24?h post mortem is recommended but preferably within 12?h post mortem. At necropsy, amount of bubbles (gas score) in decomposition code 2 in stranded cetaceans was found to be more important than merely presence vs. absence of bubbles from a pathological point of view. Deep divers presented higher abundance of gas bubbles, mainly composed of 70% nitrogen and 30% CO(2), suggesting a higher predisposition of these species to suffer from decompression-related gas embolism. PMID:22675306

  20. Defect effects on the physical and electrochemical properties of nanoscale LiFe0.92PO4 and LiFe0.92PO4/C/graphene composites.

    PubMed

    Wang, Yan; Feng, Zhe-sheng; Zhang, Chuan; Yu, Le; Chen, Jin-ju; Hu, Jing; Liu, Xing-zhao

    2013-05-01

    Nanoscale LiFe0.92PO4 and LiFe0.92PO4/C/graphene composites including defects as performance-improved cathode materials for lithium-ion batteries were prepared by a carbothermal reduction method. The physical and electrochemical properties of samples were characterized by means of X-ray diffraction, inductively coupled plasma optical emission spectrometry, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and electrochemical testing techniques. The results confirmed that defects existed within the nanoscale LiFe0.92PO4 lattice and had significant effects on improving the electrochemical properties of samples. The excellent graphene sheets covered on nanoparticles and formed a three-dimensional conductive network in nanoscale LiFe0.92PO4/C/graphene composites. The composites exhibited a discharge capacity of 90 mA h g(-1) at 10 C and capacity retention ratios of 98% after 100 cycles at various rates, implying outstanding high-rate capability and cycling stability. PMID:23493954

  1. Glass Composition Constraint Recommendations for Use in Life-Cycle Mission Modeling

    SciTech Connect

    McCloy, John S.; Vienna, John D.

    2010-05-03

    The component concentration limits that most influence the predicted Hanford life-cycle HLW glass volume by HTWOS were re-evaluated. It was assumed that additional research and development work in glass formulation and melter testing would be performed to improve the understanding of component effects on the processability and product quality of these HLW glasses. Recommendations were made to better estimate the potential component concentration limits that could be applied today while technology development is underway to best estimate the volume of HLW glass that will eventually be produced at Hanford. The limits for concentrations of P2O5, Bi2O3, and SO3 were evaluated along with the constraint used to avoid nepheline formation in glass. Recommended concentration limits were made based on the current HLW glass property models being used by HTWOS (Vienna et al. 2009). These revised limits are: 1) The current ND should be augmented by the OB limit of OB ? 0.575 so that either the normalized silica (NSi) is less that the 62% limit or the OB is below the 0.575 limit. 2) The mass fraction of P2O5 limit should be revised to allow for up to 4.5 wt%, depending on CaO concentrations. 3) A Bi2O3 concentration limit of 7 wt% should be used. 4) The salt accumulation limit of 0.5 wt% SO3 may be increased to 0.6 wt%. Again, these revised limits do not obviate the need for further testing, but make it possible to more accurately predict the impact of that testing on ultimate HLW glass volumes.

  2. Europa's Crust and Ocean: Origin, Composition, and the Prospects for Life

    NASA Astrophysics Data System (ADS)

    Kargel, Jeffrey S.; Kaye, Jonathan Z.; Head, James W.; Marion, Giles M.; Sassen, Roger; Crowley, James K.; Ballesteros, Olga Prieto; Grant, Steven A.; Hogenboom, David L.

    2000-11-01

    We have considered a wide array of scenarios for Europa's chemical evolution in an attempt to explain the presence of ice and hydrated materials on its surface and to understand the physical and chemical nature of any ocean that may lie below. We postulate that, following formation of the jovian system, the europan evolutionary sequence has as its major links: (a) initial carbonaceous chondrite rock, (b) global primordial aqueous differentiation and formation of an impure primordial hydrous crust, (c) brine evolution and intracrustal differentiation, (d) degassing of Europa's mantle and gas venting, (e) hydrothermal processes, and (f) chemical surface alteration. Our models were developed in the context of constraints provided by Galileo imaging, near infrared reflectance spectroscopy, and gravity and magnetometer data. Low-temperature aqueous differentiation from a carbonaceous CI or CM chondrite precursor, without further chemical processing, would result in a crust/ocean enriched in magnesium sulfate and sodium sulfate, consistent with Galileo spectroscopy. Within the bounds of this simple model, a wide range of possible layered structures may result; the final state depends on the details of intracrustal differentiation. Devolatilization of the rocky mantle and hydrothermal brine reactions could have produced very different ocean/crust compositions, e.g., an ocean/crust of sodium carbonate or sulfuric acid, or a crust containing abundant clathrate hydrates. Realistic chemical-physical evolution scenarios differ greatly in detailed predictions, but they generally call for a highly impure and chemically layered crust. Some of these models could lead also to lateral chemical heterogeneities by diapiric upwellings and/or cryovolcanism. We describe some plausible geological consequences of the physical-chemical structures predicted from these scenarios. These predicted consequences and observed aspects of Europa's geology may serve as a basis for further analys is and discrimination among several alternative scenarios. Most chemical pathways could support viable ecosystems based on analogy with the metabolic and physiological versatility of terrestrial microorganisms.

  3. Influence of Ply Waviness on Fatigue Life of Tapered Composite Flexbeam Laminates

    NASA Technical Reports Server (NTRS)

    Murri, Gretchen B.

    1999-01-01

    Nonlinear tapered flexbeam laminates, with significant ply waviness, were cut from a full-size composite rotor hub flexbeam. The specimens were tested under combined axial tension and cyclic bending loads. All of the specimens had wavy plies through the center and near the surfaces (termed marcelled areas), although for some of the specimens the surface marcels were very obvious, and for others they were much smaller. The specimens failed by first developing cracks through the marcels at the surfaces, and then delaminations grew from those cracks, in both directions. Delamination failure occurred in these specimens at significantly shorter fatigue lives than similar specimens without waviness, tested in ref. 2. A 2D finite element model was developed which closely approximated the flexbeam geometry, boundary conditions, and loading. In addition, the FE model duplicated the waviness observed in one of the test specimens. The model was analyzed using a geometrically nonlinear FE code. Modifications were made to the original model to reduce the amplitude of the marcels near the surfaces. The analysis was repeated for each modification. Comparisons of the interlaminar normal stresses, sigma(sub n), in the various models showed that under combined axial-tension and cyclic-bending loading, for marcels of the same aspect ratio, sigma(sub n) stresses increased as the distance along the taper, from thick to thin end, increased. For marcels of the same aspect ratio and at the same X-location along the taper, sigma(sub n) stresses decreased as the distance from the surface into the flexbeam interior increased. A technique was presented for determining the smallest acceptable marcel aspect ratio at various locations in the flexbeam.

  4. Europa's Crust and Ocean: Origin, Composition, and the Prospects for Life

    USGS Publications Warehouse

    Kargel, J.S.; Kaye, J.Z.; Head, J. W., III; Marion, G.M.; Sassen, R.; Crowley, J.K.; Ballesteros, O.P.; Grant, S.A.; Hogenboom, D.L.

    2000-01-01

    We have considered a wide array of scenarios for Europa's chemical evolution in an attempt to explain the presence of ice and hydrated materials on its surface and to understand the physical and chemical nature of any ocean that may lie below. We postulate that, following formation of the jovian system, the europan evolutionary sequence has as its major links: (a) initial carbonaceous chondrite rock, (b) global primordial aqueous differentiation and formation of an impure primordial hydrous crust, (c) brine evolution and intracrustal differentiation, (d) degassing of Europa's mantle and gas venting, (e) hydrothermal processes, and (f) chemical surface alteration. Our models were developed in the context of constraints provided by Galileo imaging, near infrared reflectance spectroscopy, and gravity and magnetometer data. Low-temperature aqueous differentiation from a carbonaceous CI or CM chondrite precursor, without further chemical processing, would result in a crust/ocean enriched in magnesium sulfate and sodium sulfate, consistent with Galileo spectroscopy. Within the bounds of this simple model, a wide range of possible layered structures may result; the final state depends on the details of intracrustal differentiation. Devolatilization of the rocky mantle and hydrothermal brine reactions could have produced very different ocean/crust compositions, e.g., an ocean/crust of sodium carbonate or sulfuric acid, or a crust containing abundant clathrate hydrates. Realistic chemical-physical evolution scenarios differ greatly in detailed predictions, but they generally call for a highly impure and chemically layered crust. Some of these models could lead also to lateral chemical heterogeneities by diapiric upwellings and/or cryovolcanism. We describe some plausible geological consequences of the physical-chemical structures predicted from these scenarios. These predicted consequences and observed aspects of Europa's geology may serve as a basis for further analys is and discrimination among several alternative scenarios. Most chemical pathways could support viable ecosystems based on analogy with the metabolic and physiological versatility of terrestrial microorganisms. ?? 2000 Academic Press.

  5. Bumble Bees (Hymenoptera: Apidae: Bombus spp.) of Interior Alaska: Species Composition, Distribution, Seasonal Biology, and Parasites

    PubMed Central

    Pampell, Rehanon; Pantoja, Alberto; Holloway, Patricia; Knight, Charles; Ranft, Richard

    2015-01-01

    Abstract Background Despite the ecological and agricultural significance of bumble bees in Alaska, very little is known and published about this important group at the regional level. The objectives of this study were to provide baseline data on species composition, distribution, seasonal biology, and parasites of the genus Bombus at three major agricultural locations within Alaska: Fairbanks, Delta Junction, and Palmer, to lay the groundwork for future research on bumble bee pollination in Alaska. New information A total of 8,250 bumble bees representing 18 species was collected from agricultural settings near Delta Junction, Fairbanks, and Palmer, Alaska in 2009 and 2010. Of the 8,250 specimens, 51% were queens, 32.7% were workers, and 16.2% were males. The species composition and relative abundances varied among sites and years. Delta Junction had the highest relative abundance of bumble bees, representing 51.6% of the specimens collected; the other two locations, Fairbanks and Palmer represented 26.5% and 21.8% of the overall catch respectively. The species collected were: Bombus bohemicus Seidl 1837 (= B. ashtoni (Cresson 1864)), B. balteatus Dahlbom 1832, B. bifarius Cresson 1878, B. centralis Cresson 1864, B. cryptarum (Fabricius 1775) (=B. moderatus Cresson 1863), B. distinguendus Morawitz 1869, B. flavidus Eversmann 1852 (=B. fernaldae Franklin 1911), B. flavifrons Cresson 1863, B. frigidus Smith 1854, B. insularis (Smith 1861), B. jonellus (Kirby 1802), B. melanopygus Nylander 1848, B. mixtus Cresson 1878, B. neoboreus Sladen 1919, B. occidentalis Greene 1858, B. perplexus Cresson 1863, B. rufocinctus Cresson 1863, and B. sylvicola Kirby 1837. Overall, the most common bumble bees near agricultural lands were B. centralis, B. frigidus, B. jonellus, B. melanopygus, B. mixtus, and B. occidentalis. Species' relative population densities and local diversity were highly variable from year to year. Bombus occidentalis, believed to be in decline in the Pacific Northwest states, represented 10.4% of the overall specimens collected from the three sites studied. Bumble bees were found to be infected by Nosema and nematodes with infection rates up to 2.1% and 16.7% respectively. Of the eight species infected by parasites, B. occidentalis displayed the highest Nosema infection, while B. centralis was the species with the highest infection of nematodes. To our knowledge this represents the first multi-year study on bumble bees from the main agricultural areas of Alaska to provide baseline data on species composition, distribution, seasonal biology, and parasites of the genus Bombus. PMID:25977613

  6. A Comparative Size-Composition-Distribution Analysis Of Xenoliths In Plutons

    NASA Astrophysics Data System (ADS)

    Gates, K.; Marko, W. T.; Yoshinobu, A. S.

    2012-12-01

    Field geologists and petrologists have long recognized the significance of xenoliths both in terms of their presence, as well as their conspicuous absence within plutonic rocks. However, few quantitative studies exist on the size and distribution of xenoliths in plutons. We report an exploratory set of size, composition, and distribution studies of xenoliths from a variety of different plutons of granodiorite to diorite composition that bear on processes of xenolith a) incorporation into magmas, b) deformation and displacement in magma chambers, c) preservation in magmas, and d) dissolution and melting in magmas. Four plutons, assembled at depths ranging from subvolcanic to 25 km, have been studied in detail (Jackass Lakes granodiorite, CA; Andalshatten granodiorite and Vega granodiorite, Norway; and Wooley Creek qtz-diorite, CA); two additional plutons (Krakfjellet, Norway, Main Donegal, Ireland) have been evaluated based on published observations. The following observations are summarized: 1) xenoliths in the studied intrusions range in size from sub-mm2 to > km2 and from << 1 to > 8% of total intrusion area, exclusive of screens that may be attached to the host rocks in 3D; 2) in plutons that intrude metasedimentary host rocks, xenoliths of carbonate/quartzite/bte-schist are common whereas pelite and pelitic migmatite are uncommon; 3) statistical size-frequency analysis of a variety of xenolith lithologies display fractal dimensions with D ~ 1 to 3 in log space over a range of sizes. However, in most cases, the density of small xenolith sizes diminishes; 4) plutons with compositions corresponding to higher solidi (e.g., tonalites, qtz diorites, gabbros, etc.) tend to contain migmatitic xenoliths (where bulk composition is appropriate), some of which underwent partial melting in situ; 5) virtually all xenoliths from mm to km in scale have been displaced relative to a fixed host-rock reference frame; none can be shown to be in situ; 6) in all plutons examined, some xenoliths have undergone post-incorporation rotation; 7) "raft trains" of xenoliths sometimes preserve ghost stratigraphy of the adjacent host rocks. However, in no case can the pre-intrusion host rock stratigraphy be restored by removing intrusive units; 8) host plutonic rocks that envelope larger xenoliths and screens often display variable textural and lithologic changes within a few meters of the xenolith including reaction halos possibly due to melt-rock reaction, and mutually intrusive felsic (sometimes pegmatitic and often hydrous) dikes; 9) metasedimentary and metavolcanic xenoliths may show evidence for ductile deformation after incorporation into the host magma, whereas meta-plutonic xenoliths generally do not; 10) hypersolidus fabric trends and magnitudes in the host plutons generally do not show any systematic variability approaching xenolith contacts. Together, these observations indicate that when preserved, xenoliths in plutons may provide a range of useful metrics to evaluate magma compositional evolution (e.g., in situ assimilation), rheology (e.g., near-solidus magma viscosity and crystallinity), and mechanisms of host rock deformation and xenolith incorporation (e.g., fragmentation processes).

  7. Using and Distributing Spaceflight Data: The Johnson Space Center Life Sciences Data Archive

    NASA Technical Reports Server (NTRS)

    Cardenas, J. A.; Buckey, J. C.; Turner, J. N.; White, T. S.; Havelka,J. A.

    1995-01-01

    Life sciences data collected before, during and after spaceflight are valuable and often irreplaceable. The Johnson Space Center Life is hard to find, and much of the data (e.g. Sciences Data Archive has been designed to provide researchers, engineers, managers and educators interactive access to information about and data from human spaceflight experiments. The archive system consists of a Data Acquisition System, Database Management System, CD-ROM Mastering System and Catalog Information System (CIS). The catalog information system is the heart of the archive. The CIS provides detailed experiment descriptions (both written and as QuickTime movies), hardware descriptions, hardware images, documents, and data. An initial evaluation of the archive at a scientific meeting showed that 88% of those who evaluated the catalog want to use the system when completed. The majority of the evaluators found the archive flexible, satisfying and easy to use. We conclude that the data archive effectively provides key life sciences data to interested users.

  8. Vegetation in Bangalore's Slums: Composition, Species Distribution, Density, Diversity, and History

    NASA Astrophysics Data System (ADS)

    Gopal, Divya; Nagendra, Harini; Manthey, Michael

    2015-06-01

    There is widespread acknowledgement of the need for biodiversity and greening to be part of urban sustainability efforts. Yet we know little about greenery in the context of urban poverty, particularly in slums, which constitute a significant challenge for inclusive development in many rapidly growing cities. We assessed the composition, density, diversity, and species distribution of vegetation in 44 slums of Bangalore, India, comparing these to published studies on vegetation diversity in other land-use categories. Most trees were native to the region, as compared to other land-use categories such as parks and streets which are dominated by introduced species. Of the most frequently encountered tree species, Moringa oleifera and Cocos nucifera are important for food, while Ficus religiosa plays a critical cultural and religious role. Tree density and diversity were much lower in slums compared to richer residential neighborhoods. There are also differences in species preferences, with most plant (herb, shrub and vines) species in slums having economic, food, medicinal, or cultural use, while the species planted in richer residential areas are largely ornamental. Historic development has had an impact on species distribution, with older slums having larger sized tree species, while recent slums were dominated by smaller sized tree species with greater economic and food use. Extensive focus on planting trees and plant species with utility value is required in these congested neighborhoods, to provide livelihood support.

  9. Monitoring of atmospheric composition with IASI and MOPITT: CO distributions and trends

    NASA Astrophysics Data System (ADS)

    George, M.; Clerbaux, C.; Hadji-Lazaro, J.; Bouarar, I.; Hurtmans, D.; Coheur, P.; Edwards, D. P.; Deeter, M. N.; Worden, H. M.

    2011-12-01

    Carbon monoxide (CO) is an important trace gas for understanding air quality and atmospheric composition. It is a good tracer of pollution plumes and atmospheric dynamics. In this talk we describe the analysis of global and regional CO distributions as seen by both the MOPITT/Terra and IASI/MetOp missions, from mid-2007 up to now. Long term trends for IASI and MOPITT (version 3, 4 and 5) CO total columns over specific areas are presented, and show excellent agreement. CO distributions over polluted and clean regions are compared. Preliminary results of a study comparing the surface CO level for the two sounders over different cities will be presented, using MOPITT version 5 products that include the NIR and show a better sensitivity near the ground. Finally, this talk will also illustrate how the data processed at ULB-LATMOS are currently assimilated in the MACC project in near-real time in order to generate the CO pollution forecasts over Europe. Surface CO obtained after assimilation show better agreement with ground-based station measurements.

  10. Vegetation in Bangalore's Slums: Composition, Species Distribution, Density, Diversity, and History.

    PubMed

    Gopal, Divya; Nagendra, Harini; Manthey, Michael

    2015-06-01

    There is widespread acknowledgement of the need for biodiversity and greening to be part of urban sustainability efforts. Yet we know little about greenery in the context of urban poverty, particularly in slums, which constitute a significant challenge for inclusive development in many rapidly growing cities. We assessed the composition, density, diversity, and species distribution of vegetation in 44 slums of Bangalore, India, comparing these to published studies on vegetation diversity in other land-use categories. Most trees were native to the region, as compared to other land-use categories such as parks and streets which are dominated by introduced species. Of the most frequently encountered tree species, Moringa oleifera and Cocos nucifera are important for food, while Ficus religiosa plays a critical cultural and religious role. Tree density and diversity were much lower in slums compared to richer residential neighborhoods. There are also differences in species preferences, with most plant (herb, shrub and vines) species in slums having economic, food, medicinal, or cultural use, while the species planted in richer residential areas are largely ornamental. Historic development has had an impact on species distribution, with older slums having larger sized tree species, while recent slums were dominated by smaller sized tree species with greater economic and food use. Extensive focus on planting trees and plant species with utility value is required in these congested neighborhoods, to provide livelihood support. PMID:25840697

  11. Compositional bias is a major determinant of the distribution pattern and abundance of palindromes in Drosophila melanogaster.

    PubMed

    Liu, Guoqing; Liu, Jia; Zhang, Bingjie

    2012-10-01

    Palindromic sequences are important DNA motifs related to gene regulation, DNA replication and recombination, and thus, investigating the evolutionary forces shaping the distribution pattern and abundance of palindromes in the genome is substantially important. In this article, we analyzed the abundance of palindromes in the genome, and then explored the possible effects of several genomic factors on the palindrome distribution and abundance in Drosophila melanogaster. Our results show that the palindrome abundance in D. melanogaster deviates from random expectation and the uneven distribution of palindromes across the genome is associated with local GC content, recombination rate, and coding exon density. Our data suggest that base composition is the major determinant of the distribution pattern and abundance of palindromes and the correlation between palindrome density and recombination is a side-product of the effect of compositional bias on the palindrome abundance. PMID:23138634

  12. USE OF MULTI-PHOTON LASER-SCANNING MICROSCOPY TO DESCRIBE THE DISTRIBUTION OF XENOBIOTIC CHEMICALS IN FISH EARLY LIFE STAGES

    EPA Science Inventory

    To better understand the mechanisms by which persistent bioaccumulative toxicants (PBTs) produce toxicity during fish early life stages (ELS), dose response relationships need to be determined in relation to the dynamic distribution of chemicals in sensitive tissues. In this stud...

  13. Comparison of Botanical Composition, Soil Carbon Content, and Root Distribution of Subirrigated Meadows in The Nebraska Sandhills

    Microsoft Academic Search

    Eric M. Mousel; Walter H. Schacht; c. William Zanner; David A. Wedin

    2007-01-01

    Characterizing vegetation composition, carbon\\/nitrogen (C\\/N) content of soils, and root-mass distribution is critical to understanding carbon sequestration potential of subirrigated meadows in the Nebraska Sandhills. Five subirrigated meadows dominated by cool-season (C3) graminoids and five meadows dominated by warm-season (C4) grasses were selected throughout the Nebraska Sandhills. Vegetation, soil carbon and nitrogen, and root-mass density distribution were sampled in each

  14. In situ formation by laser cladding of a TiC composite coating with a gradient distribution

    Microsoft Academic Search

    Xiaolei Wu

    1999-01-01

    An in situ method was developed to produce an Ni alloy composite coating reinforced by in situ reacted TiC particles with a gradient distribution, using one-step laser cladding with a pre-placed powder mixture on a 5CrMnMo steel substrate. Dispersed and ultra-fine TiC particles were formed in situ in the coating. Most of the TiC particles, with a marked gradient distribution,

  15. Vertical distribution and composition of phytoplankton under the influence of an upper mixed layer.

    PubMed

    Ryabov, Alexei B; Rudolf, Lars; Blasius, Bernd

    2010-03-01

    The vertical distribution of phytoplankton is of fundamental importance for the dynamics and structure of aquatic communities. Here, using an advection-reaction-diffusion model, we investigate the distribution and competition of phytoplankton species in a water column, in which inverse resource gradients of light and a nutrient can limit growth of the biomass. This problem poses a challenge for ecologists, as the location of a production layer is not fixed, but rather depends on many internal parameters and environmental factors. In particular, we study the influence of an upper mixed layer (UML) in this system and show that it leads to a variety of dynamic effects: (i) Our model predicts alternative density profiles with a maximum of biomass either within or below the UML, thereby the system may be bistable or the relaxation from an unstable state may require a long-lasting transition. (ii) Reduced mixing in the deep layer can induce oscillations of the biomass; we show that a UML can sustain these oscillations even if the diffusivity is less than the critical mixing for a sinking phytoplankton population. (iii) A UML can strongly modify the outcome of competition between different phytoplankton species, yielding bistability both in the spatial distribution and in the species composition. (iv) A light limited species can obtain a competitive advantage if the diffusivity in the deep layers is reduced below a critical value. This yields a subtle competitive exclusion effect, where the oscillatory states in the deep layers are displaced by steady solutions in the UML. Finally, we present a novel graphical approach for deducing the competition outcome and for the analysis of the role of a UML in aquatic systems. PMID:19896955

  16. Distribution of early life history stages of fishes in selected pools of the Upper Mississippi River

    Microsoft Academic Search

    Leslie E. Holland

    1986-01-01

    Effective management of the fishery resources of the Upper Mississippi River and successful mitigation of the loss of critical habitat depend in part on an understanding of the reproductive and early life history requirements of the affected fishes. However, little is known about the use of nursery areas by fishes in the river. Of the nearly 130 species identified in

  17. The influence of birthweight and intrauterine environment on adiposity and fat distribution in later life

    Microsoft Academic Search

    I Rogers

    2003-01-01

    OBJECTIVE: To review the literature on the association between birthweight and body mass index (BMI) and obesity in later life.METHODS: Included in the review were papers appearing in Medline since 1966 and identified using the search terms obesity, body fat, waist, body constitution, birthweight and birth weight. Further papers were identified by examining bibliographies.RESULTS: There is good evidence that there

  18. Effect of the loading spectrum and history length on fatigue life distribution under random loading

    Microsoft Academic Search

    J. Dominguez; J. Zapatero

    1992-01-01

    One major source of error commonly encountered in determining the fatigue life of a given element arises from the loads involved, which are usually of random nature. As a rule, resistance analyses, carried out by simulation or tests, are done by using a loading history accounting for the real loads involved that is repeated indefinitely until failure is encountered. The

  19. Does diet breadth control herbivorous insect distribution size? Life history and resource outlets for specialist butterflies

    Microsoft Academic Search

    Roger L. H. Dennis; Tim G. Shreeve; Henry R. Arnold; David B. Roy

    2005-01-01

    Although butterfly distributions are known to be positively correlated with the number of larval hostplants used it is not known to what extent larval hostplant number uniquely influences butterfly distributions and to what extent effects are indirect through other variables. This issue is central to understanding the part generalism and specialism in host use play in organism persistence and conservation.

  20. Life Testing and Reliability Estimation for the Two Parameter Exponential Distribution

    Microsoft Academic Search

    S. D. Varde

    1969-01-01

    A Bayesian approach to the estimation of the parameters of a two-parameter exponential distribution and the reliability function associated with it is developed using censored samples. Bayesian point estimates are obtained for these three quantities and it is shown that under a suitable choice of the prior distribution and of the loss function they are approximately equivalent to the corresponding

  1. Measurement Issues Related to Studies of Childhood Obesity: Assessment of Body Composition, Body Fat Distribution, Physical Activity, and Food Intake

    Microsoft Academic Search

    Michael I. Goran

    This article reviews the current status of various methodologies used in obesity and nutrition re- search in children, with particular emphasis on identify- ing priorities for research needs. The focus of the article is 1) to review methodologic aspects involved with mea- surement of body composition, body-fat distribution, en- ergy expenditure and substrate use, physical activity, and food intake in

  2. Source apportionment of ambient particles: Comparison of positive matrix factorization analysis applied to particle size distribution and chemical composition data

    Microsoft Academic Search

    Jianwei Gu; Mike Pitz; Jürgen Schnelle-Kreis; Jürgen Diemer; Armin Reller; Ralf Zimmermann; Jens Soentgen; Matthias Stoelzel; H.-Erich Wichmann; Annette Peters; Josef Cyrys

    2011-01-01

    Positive matrix factorization (PMF) method was used to identify the sources of ambient particles (PM10) in Augsburg in winter 2006\\/07. The analyses were carried out separately with particulate chemical composition (PCC) data at an urban traffic site and with particle size distribution (PSD) data at an urban background site on daily and hourly base, respectively. For PCC data, six factors

  3. Eddy-induced oscillations of the pycnocline affect the floristic composition and depth distribution of phytoplankton in the subtropical Pacific

    Microsoft Academic Search

    M. Olaizola; D. A. Ziemann; P. K. Bienfang; W. A. Walsh; L. D. Conquest

    1993-01-01

    Changes in the phytoplankton population caused by a wind-induced mesoscale eddy, first located off the Hawaiian chain on 29 August 1989, were examined from 6 to 12 September 1989. These cyclonic eddies produce upwelling of nutrient-rich water into the photic zone which may induce changes in the distribution of phytoplankton. The eddy affected the depth, magnitude and composition of the

  4. Distribution, abundance and carbon isotopic composition of gaseous hydrocarbons in Big Soda Lake, Nevada - An alkaline, meromictic lake

    Microsoft Academic Search

    R. S. Oremland; D. J. Des Marais

    1983-01-01

    The study of the distribution and isotopic composition of low molecular weight hydrocarbon gases at the Big Soda Lake, Nevada, has shown that while neither ethylene nor propylene were found in the lake, ethane, propane, isobutane and n-butane concentrations all increased with water column depth. It is concluded that methane has a biogenic origin in both the sediments and the

  5. Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes

    EPA Science Inventory

    The stability of iron corrosion products and the bacterial composition of biofilm in drinking water distribution systems (DWDS) could have great impact on the water safety at the consumer ends. In this work, pipe loops were setup to investigate the transformation characteristics ...

  6. Nutrient composition of banked human milk in brazil and influence of processing on zinc distribution in milk fractions

    Microsoft Academic Search

    Helo??sa C. A Góes; Alexandre G Torres; Carmen M Donangelo; Nadia M. F Trugo

    2002-01-01

    OBJECTIVE AND METHODS: We measured the contents of fat, protein, lactose, calcium, phosphorus, zinc, iron, copper, and vitamin A in processed mature milk samples (individual, n = 60, and pooled, n = 10) from a reference human milk bank in Brazil and assessed the effect of pasteurization followed by freezing on the nutrient composition and the pattern of zinc distribution

  7. Distribution free procedures for make-to-order (MTO), make-in-advance (MIA), and composite policies

    Microsoft Academic Search

    Ilkyeong Moon; Sangjin Choi

    1997-01-01

    The purpose of this paper is to study the make-to-order (MTO), make-in-advance (MIA), and composite policies in a single period two echelon stochastic model with more realistic assumptions. We relax the assumption that the cumulative distribution function of demand is completely known and merely assume that its first two moments are known.

  8. [Composition, abundance and distribution of populations of commercially important gastropods in La Guajira, Colombian Caribbean].

    PubMed

    Nieto-Bernal, Ramón; Luis, Chasqui; Rodriguez, Angélica María; Castro, Erick; Gil-Agudelo, Diego L

    2013-06-01

    In the continental Colombian Caribbean the conch resource exploitation and the status of snails populations has been poorly studied, which are reflected in the lack of fisheries management. This study assesses composition, population density and distribution of the gastropods species that make conch resource in La Guajira region. Underwater visual censuses for snails were performed between September-November 2009 in 145100x4m (400m2) transects, spanning a total area of 56920m2 between Riohacha and Cabo de la Vela. The study was complemented with the evaluation of composition, abundance and size of gastropods conch found in the discarded-by-fishermen shell mounds in 13 beaches. In October 2010 another 40 transects were evaluated (16 000 m2) from the Southern of Riohacha to the Camarones village (La Guajira). We found a total of 9911 snails belonging to 12 species, the most abundant being Strombus pugilis with 8 912 individuals and an average density of 1 538.4 +/- 3 662.6 ind./ha, followed by Vasum muricatum with 374 individuals and an average density of 51.8 +/- 91.2 ind./ha. Calculating the importance value index (IVI) for both living organisms as the empty shells on beaches, shows that Turbinella angulata is the most used species by artisanal fishermen in the region. Cassis madagascariensis and Cassis tuberosa are also important snail resources in the region (as suggested by the number of empty shells found in beaches), but its densities were low. Strombus gigas, with only three living organisms found in the area, presented the lowest abundance ever found in the Colombian Caribbean (0.52 +/- 3.6 ind./ha), showing that queen conch population in La Guajira cannot support commercial exploitation. The abundance of discarded S. gigas shells on beaches suggests resource exploitation in the recent past. Results remarks the urgency of implementing management plans for snail fisheries in the region. PMID:23885583

  9. Application of composite flow laws to grain size distributions derived from polar ice cores

    NASA Astrophysics Data System (ADS)

    Binder, Tobias; de Bresser, Hans; Jansen, Daniela; Weikusat, Ilka; Garbe, Christoph; Kipfstuhl, Sepp

    2014-05-01

    Apart from evaluating the crystallographic orientation, focus of microstructural analysis of natural ice during the last decades has been to create depth-profiles of mean grain size. Several ice flow models incorporated mean grain size as a variable. Although such a mean value may coincide well with the size of a large proportion of the grains, smaller/larger grains are effectively ignored. These smaller/larger grains, however, may affect the ice flow modeling. Variability in grain size is observed on centimeter, meter and kilometer scale along deep polar ice cores. Composite flow laws allow considering the effect of this variability on rheology, by weighing the contribution of grain-size-sensitive (GSS, diffusion/grain boundary sliding) and grain-size-insensitive (GSI, dislocation) creep mechanisms taking the full grain size distribution into account [1]. Extraction of hundreds of grain size distributions for different depths along an ice core has become relatively easy by automatic image processing techniques [2]. The shallow ice approximation is widely adopted in ice sheet modeling and approaches the full-Stokes solution for small ratios of vertical to horizontal characteristic dimensions. In this approximation shear stress in the vertical plain dominates the strain. This assumption is not applicable at ice divides or dome structures, where most deep ice core drilling sites are located. Within the upper two thirds of the ice column longitudinal stresses are not negligible and ice deformation is dominated by vertical strain. The Dansgaard-Johnsen model [3] predicts a dominating, constant vertical strain rate for the upper two thirds of the ice sheet, whereas in the lower ice column vertical shear becomes the main driver for ice deformation. We derived vertical strain rates from the upper NEEM ice core (North-West Greenland) and compared them to classical estimates of strain rates at the NEEM site. Assuming intervals of constant accumulation rates, we found a variation of vertical strain rates by a factor 2-3 in the upper ice column. We discuss the current applicability of composite flow laws to grain size distributions extracted from ice cores drilled at sites where the flow direction rotates by 90 degrees with depth (i.e. ice divide). An interesting finding is that a transition to a glacial period in future would be associated with a decrease in vertical strain rate (due to a reduced accumulation rate) and an increase of the frequency of small grains (due to an enhanced impurity content). Composite flow laws assign an enhanced contribution of GSS creep to this transition. It is currently unclear which factor would have a greater influence. [1] Herwegh et al., 2005, J. Struct. Geol., 27, 503-521 [2] T. Binder et al., 2013, J. Microsc., 250, 130-141 [3] W. Dansgaard & S.J. Johnsen, 1969, J. Glaciol., 8, 215-223

  10. Life cycle and geographic distribution of the gymnophallid Bartolius pierrei (Digenea) on the Patagonian coast, Argentina

    Microsoft Academic Search

    Florencia Cremonte

    2004-01-01

    The life cycle of the gymnophallid Bartolius pierrei Cremonte, 2001 (Digenea) at Fracasso Beach (the type locality) (42°25?S, 64°07?W), Península Valdés, Argentina, was elucidated. This digenean uses the clam Darina solenoides (Mactridae) as both first and second intermediate host. The Kelp Gull, Larus dominicanus, and the Red Knot, Calidris canutus rufa, a Neotropical migratory bird, act as definitive hosts. A

  11. The composition and size distribution of the dust in the coma of comet Hale-Bopp

    E-print Network

    M. Min; J. W. Hovenier; A. de Koter; L. B. F. M. Waters; C. Dominik

    2005-05-30

    We discuss the composition and size distribution of the dust in the coma of comet Hale-Bopp. We do this by fitting simultaneously the infrared emission spectrum measured by the infrared space observatory (ISO) and the measured degree of linear polarization of scattered light at various phase angles and 12 different wavelengths. The effects of particle shape on the modeled optical properties of the dust grains are taken into account. We constrain our fit by forcing the abundances of the major rock forming chemical elements to be solar. The infrared spectrum at long wavelengths reveals that large grains are needed in order to fit the spectral slope. The size and shape distribution we employ allows us to estimate the sizes of the crystalline silicates. The ratios of the strength of various forsterite features show that the crystalline silicate grains in Hale-Bopp must be submicron sized. We exclude the presence of large crystalline silicate grains in the coma. Because of this lack of large crystalline grains combined with the fact that we do need large amorphous grains to fit the emission spectrum at long wavelengths, we need only approximately 4% of crystalline silicates by mass. After correcting for possible hidden crystalline material included in large amorphous grains, our best estimate of the total mass fraction of crystalline material is approximately 7.5%, significantly lower than deduced in previous studies in which the typical derived crystallinity is 20-30%. The implications of this on the possible origin and evolution of the comet are discussed. The crystallinity we observe in Hale-Bopp is consistent with the production of crystalline silicates in the inner solar system by thermal annealing and subsequent radial mixing to the comet forming region.

  12. The effect of mesostructure heterogeneity on cracks initiation and the displacement distribution in NCF composites

    Microsoft Academic Search

    H Zrida; K Giannadis; J Varna

    2012-01-01

    Non Crimp Fabrics (NCF) are promising new generation composite materials. They are now being used in some sections of composite industry, for example in wind turbine blades and boat hulls. The aerospace industry also shows an increasing interest in this material, thanks to the low cost of its manufacturing process. NCFs are special types of textile composites, made of layers

  13. Structural Health Monitoring of Composite Materials Using Distributed Fiber Bragg Sensors

    NASA Technical Reports Server (NTRS)

    Grant, Joseph; Kual, Raj; Taylor, Scott; Jackson, Kurt V.; Myers, George; Wang, Y.; Sharma, A.; Burdine, Robert (Technical Monitor)

    2002-01-01

    Health monitoring of polymer matrix composite materials using fiber optic Bragg grating (FBG) sensors is accomplished using a tunable IR (infrared) laser via transmission mode. Results are presented from experiments of composite structures with FBG's embedded at various orientations, and surface measurements of various cryogenic composite vessels.

  14. Spatial variation in life-history trade-offs results in an ideal free distribution in Black Brant Geese.

    PubMed

    Nicolai, Christopher A; Sedinger, James S; Ward, David H; Boyd, W Sean

    2014-05-01

    Ideal free distribution theory predicts that individuals distribute themselves so fitness is equal among patches. In this paper we evaluate all components of adult fitness to assess the hypothesis that individuals distribute themselves among seven brood-rearing areas so that trade-offs among different life history traits result in equal mean fitness among individuals using different areas. We used estimates of vital rates (clutch size, nest survival, pre-fledging survival, post-fledging survival, juvenile survival, and breeding probability) to estimate brood-rearing-area-specific per capita recruitment rates and survival for adult females. We summed brood-rearing-area-specific per capita recruitment and adult survival to calculate brood-rearing-area-specific estimates of lambda. We found little variation in lambda among brood-rearing areas and lifetime fitness implications of changing brood-rearing area were negligible (< 1% brood-rearing area mean fitness). We conclude that adult female Black Brant distribute themselves in an ideal free manner, resulting in equal fitness among females using these areas. PMID:25000763

  15. Bacterial composition in a metropolitan drinking water distribution system utilizing different source waters.

    PubMed

    Gomez-Alvarez, Vicente; Humrighouse, Ben W; Revetta, Randy P; Santo Domingo, Jorge W

    2015-03-01

    We investigated the bacterial composition of water samples from two service areas within a drinking water distribution system (DWDS), each associated with a different primary source of water (groundwater, GW; surface water, SW) and different treatment process. Community analysis based on 16S rRNA gene clone libraries indicated that Actinobacteria (Mycobacterium spp.) and ?-Proteobacteria represented nearly 43 and 38% of the total sequences, respectively. Sequences closely related to Legionella, Pseudomonas, and Vibrio spp. were also identified. In spite of the high number of sequences (71%) shared in both areas, multivariable analysis revealed significant differences between the GW and SW areas. While the dominant phylotypes where not significantly contributing in the ordination of samples, the populations associated with the core of phylotypes (1-10% in each sample) significantly contributed to the differences between both service areas. Diversity indices indicate that the microbial community inhabiting the SW area is more diverse and contains more distantly related species coexisting with local assemblages as compared with the GW area. The bacterial community structure of SW and GW service areas were dissimilar, suggesting that their respective source water and/or water quality parameters shaped by the treatment processes may contribute to the differences in community structure observed. PMID:25719474

  16. Distribution and size composition of the arctic lamprey Lethenteron camtschaticum in the North Pacific

    NASA Astrophysics Data System (ADS)

    Orlov, A. M.; Baitalyuk, A. A.; Pelenev, D. V.

    2014-03-01

    Results of the long-term study of the spatial and vertical distribution of the parasitic anadromous Arctic lamprey Lethenteron camtschaticum (Tilesius, 1811) (Petromyzontidae) in the North Pacific and data on its size composition are given. This species is most frequent in the northwestern Sea of Japan and the western Bering Sea. The maximum concentrations are noted in waters of southern Primorye, southwestern Sakhalin, the northwestern part of the Sea of Okhotsk, and the northern part of the Bering Sea, which is probably explained by the increased number of its victims, Pacific salmon. Near the bottom, Pacific lampreys are extremely few and are primarily encountered at depths less that 400 m, and in the Pelagic zone, in the 100-m layer. The catches have contained Arctic lampreys having a total length of 15-79 cm. The lampreys of several size groups in the catches may indicate that L. camtschaticum spends not less than four years in the sea. No relationship has been found between the body length and the capture depth. Analyzed are the relationships between the body length and weight and the body length and the condition factor. The seasonal dynamics of these indices are considered.

  17. Spatiotemporal distribution and composition of phytoplankton assemblages in a coastal tropical lagoon: Chilika, India.

    PubMed

    Srichandan, Suchismita; Kim, Ji Yoon; Bhadury, Punyasloke; Barik, Saroja K; Muduli, Pradipta R; Samal, Rabindro N; Pattnaik, Ajit K; Rastogi, Gurdeep

    2015-02-01

    The Asia's largest lagoon, Chilika, is a shallow water estuary and a designated "Ramsar" site located in the east coast of India. The spatiotemporal diversity of phytoplankton based on the monthly sampling between July 2011 and June 2012 was investigated in relation to physicochemical variables of the surface water column from 13 stations. The salinity was minimum (average 9) during the monsoon which was primarily due to riverine discharge. As the season progressed towards post-monsoon, average salinity of the whole lagoon reached to 10 which further increased to 20 during pre-monsoon season. A total of 259 species of phytoplankton, mostly dominated by the Bacillariophyta (138 species) followed by Dinophyta (38 species), Chlorophyta (32 species), Cyanophyta (29 species), Euglenophyta (18 species), and Chrysophyta (4 species), were recorded in this study. Different ecological sectors of the lagoon (except the northern sector) were dominated by diatoms, while the northern sector due to its freshwater regime supported large population of euglenoids. Based on the multivariate ordination analysis, salinity regime and light availability played important role in determining the distribution, diversity, and composition of phytoplankton communities. Overall, this study documented a very high diversity of phytoplankton and highlighted the importance of taking extensive sampling in getting a clearer understanding of phytoplankton community structure in less-studied environments such as Chilika lagoon. PMID:25638055

  18. Composition and Distribution of Streambed Sediments in the Penobscot River, Maine, May 1999

    USGS Publications Warehouse

    Dudley, Robert W.; Giffen, Sarah E.

    2001-01-01

    Sediment samples were collected and geophysical surveys were run along 50 miles of the Penobscot River, Maine, in the spring of 1999 to produce maps that describe the composition and distribution of streambed sediments for selected areas in the river channel. The objective of the sediment survey was to locate areas along the river where fine-grained, easily transportable sediment types were deposited between Old Town and Medway, Maine. These data can be used to design future sediment-sampling programs to assess the quality of streambed sediments and evaluate the health of the Penobscot River. This report describes the results of the sediment survey and the methods used to collect, analyze, and interpret the data used to create maps of streambed-sediment types in the study area. Deposits of fine-grained sediments (mud and sand) are scattered along the shorelines of the mainland and the islands and at the downstream ends of islands and at the mouths of brooks and streams. The most extensive depositional areas were found in the Mattaseunk Dam impoundment near Medway. The main areas of the river channel consist primarily of gravel, sand, and rock.

  19. Affixation in semantic space: Modeling morpheme meanings with compositional distributional semantics.

    PubMed

    Marelli, Marco; Baroni, Marco

    2015-07-01

    The present work proposes a computational model of morpheme combination at the meaning level. The model moves from the tenets of distributional semantics, and assumes that word meanings can be effectively represented by vectors recording their co-occurrence with other words in a large text corpus. Given this assumption, affixes are modeled as functions (matrices) mapping stems onto derived forms. Derived-form meanings can be thought of as the result of a combinatorial procedure that transforms the stem vector on the basis of the affix matrix (e.g., the meaning of nameless is obtained by multiplying the vector of name with the matrix of -less). We show that this architecture accounts for the remarkable human capacity of generating new words that denote novel meanings, correctly predicting semantic intuitions about novel derived forms. Moreover, the proposed compositional approach, once paired with a whole-word route, provides a new interpretative framework for semantic transparency, which is here partially explained in terms of ease of the combinatorial procedure and strength of the transformation brought about by the affix. Model-based predictions are in line with the modulation of semantic transparency on explicit intuitions about existing words, response times in lexical decision, and morphological priming. In conclusion, we introduce a computational model to account for morpheme combination at the meaning level. The model is data-driven, theoretically sound, and empirically supported, and it makes predictions that open new research avenues in the domain of semantic processing. (PsycINFO Database Record PMID:26120909

  20. Fatigue behavior and life prediction of a SiC/Ti-24Al-11Nb composite under isothermal conditions. Ph. D. Thesis

    SciTech Connect

    Bartolotta, P.A.

    1991-08-01

    Metal Matrix Composites (MMC) and Intermetallic Matrix Composites (IMC) were identified as potential material candidates for advanced aerospace applications. They are especially attractive for high temperature applications which require a low density material that maintains its structural integrity at elevated temperatures. High temperature fatigue resistance plays an important role in determining the structural integrity of the material. This study attempts to examine the relevance of test techniques, failure criterion, and life prediction as they pertain to an IMC material, specifically, unidirectional SiC fiber reinforced titanium aluminide. A series of strain and load controlled fatigue tests were conducted on unidirectional SiC/Ti-24Al-11Nb composite at 425 and 815 C. Several damage mechanism regimes were identified by using a strain-based representation of the data, Talreja's fatigue life diagram concept. Results of these tests were then used to address issues of test control modes, definition of failure, and testing techniques. Finally, a strain-based life prediction method was proposed for an IMC under tensile cyclic loadings at elevated temperatures.

  1. Distributed feedback lasing from a composite poly(phenylene vinylene)-nanoparticle one-dimensional photonic crystal.

    PubMed

    Puzzo, Daniel P; Scotognella, Francesco; Zavelani-Rossi, Margherita; Sebastian, Maria; Lough, Alan J; Manners, Ian; Lanzani, Guglielmo; Tubino, Riccardo; Ozin, Geoffrey A

    2009-12-01

    Nanoparticle one-dimensional photonic crystals exhibit intense, broadband reflectivity coupled with a unique mesoporosity. The latter property allows for infiltration of the one-dimensional photonic crystal with functional materials, such as emitting polymers, which in turn can lead to the fabrication of composites whereby the emitter's emission can be modulated by the photon density of states of the photonic crystal. We exploit this interaction in order to produce efficient distributed feedback lasing from a composite poly(phenylene vinylene)-infiltrated nanoparticle one-dimensional photonic crystal. PMID:19842702

  2. Optimal preventive-replacement intervals for the Weibull life distribution: solutions and applications

    Microsoft Academic Search

    J. Huang; C. R. Miller; O. G. Okogbaa

    1995-01-01

    Using a well-known single-unit replacement model with Weibull failure distribution assumption, normalization is used to reduce the model input parameters such that standard optimal preventive replacement solutions can be generated. Characteristics of the model solutions are discussed. The standard solutions are organized in charts and tables for ease of use. Procedures are developed and examples are given for applying the

  3. Probabilistic fatigue life prediction using an equivalent initial flaw size distribution

    Microsoft Academic Search

    Yongming Liu; Sankaran Mahadevan

    2009-01-01

    A new methodology is proposed in this paper to calculate the equivalent initial flaw size (EIFS) distribution. The proposed methodology is based on the Kitagawa–Takahashi diagram. Unlike the commonly used back-extrapolation method for EIFS calculation, the proposed methodology is independent of applied load level and only uses fatigue limit and fatigue crack threshold stress intensity factor. The advantage of the

  4. Rate of Return to Education: A Distributional Analysis Using the LifePaths Model

    ERIC Educational Resources Information Center

    Boothby, Daniel; Rowe, Geoff

    2002-01-01

    This paper reports estimates of the distribution of individual private rates of return to undergraduate and community college education by field of study for Canada. It is important to know the dispersion of the private rate of return to post-secondary education, as well as its average level. There are very different implications for…

  5. The LifeWatch approach to the exploration of distributed species information

    PubMed Central

    Fuentes, Daniel; Fiore, Nicola

    2014-01-01

    Abstract This paper introduces a new method of automatically extracting, integrating and presenting information regarding species from the most relevant online taxonomic resources. First, the information is extracted and joined using data wrappers and integration solutions. Then, an analytical tool is used to provide a visual representation of the data. The information is then integrated into a user friendly content management system. The proposal has been implemented using data from the Global Biodiversity Information Facility (GBIF), the Catalogue of Life (CoL), the World Register of Marine Species (WoRMS), the Integrated Taxonomic Information System (ITIS) and the Global Names Index (GNI). The approach improves data quality, avoiding taxonomic and nomenclature errors whilst increasing the availability and accessibility of the information. PMID:25589865

  6. Lithium Isotopic Composition of Mantle Plumes and the Distribution of Lithium Isotopes Among Earth's Reservoirs

    NASA Astrophysics Data System (ADS)

    Chan, L.; Hart, S. R.; Blusztajn, J. S.; Lassiter, J. C.; Frey, F. A.; Hauri, E. H.

    2006-12-01

    We have determined lithium isotopic compositions of seventy nearly unaltered basaltic lavas from the Samoan and Cook-Austral volcanic chains, and Pitcairn Island. In addition, the Li isotope record of Mauna Kea has been extended from 3.1 km to 3.3 km using the newly recovered deep drill core of Hawaii Scientific Drilling Project (HSDP-2). From the results of the Hawaii and South Pacific hotspots, we examine the source components of mantle plumes and consider the distribution of Li isotopes among Earth's major reservoirs. The total ?^{7}Li range observed in South Pacific and Hawaiian islands is 2.5 to 7.5‰, suggesting considerable heterogeneity in the deep mantle. The Hawaiian plume occupies the lower range, 2.5 to 5.7‰. Cook-Austral samples depict mixing between HIMU and depleted mantle (DM) components. The DM endmember has ?^{7}Li values of 3.2 to 4.2‰, identical to MORB. HIMU type lavas are isotopically heavier than MORB, reflecting the influence of recycled oceanic crust. The most extreme HIMU signature was observed at Mangaia (7.4‰; Nishio et al., 2005). The EM1 composition shown by Pitcairn is relatively light (3.3 to 4.1‰) and resembles the global average of subducting sediments (~3‰). Malumalu seamount of the Samoan chain defines the most extreme composition of the EM2 mantle; ?^{7}Li range from 4.5 to 5.6‰. High 3He/4He samples of Ofu Island (R/Ra = 24 to 33.7) suggest that the least degassed mantle has ?^{7}Li of about 3‰. In addition to these classic mantle endmembers, we observe an additional component that elevates Samoan lavas above the typical mantle baseline (~3‰) up to 7.5‰. The source of this enrichment is likely mantle wedge material that has been metasomatized by 7Li-rich slab fluids (Elliott et al., 2004). On the other hand, recent studies suggest that a large portion of subducted Li can be retained in high-pressure metamorphosed slab (Marschall et al., in press). This implies that deeply subducted slab need not be isotopically light but can be the origin of elevated ?^{7}Li of HIMU lavas. The global ocean island basalts yield an average ?^{7}Li value of 4.7 ± 0.9‰ (1?). Thus the deep mantle is isotopically heavier than the upper mantle (3 to 4‰), volcanic arcs (3.5 ± 1.5‰), and the upper continental crust (0 ± 2‰). The implication is that heavy Li that enters the subduction zone is not significantly recycled to the crust but largely returned to the deep mantle via the slab-modified mantle wedge and possibly the residual slab. Unusually light Li does not appear to to be common in the deep mantle although it has been implicated by orogenic eclogites and subcontinental mantle xenoliths. References: Elliott T., A. Jeffcoate, and C. Bouman (2004) Earth Planet. Sci. Lett. 220, 231-245. Marschall H.R., R. Altherr, T. Ludwig et al. (in press) Geochim. Cosmochim. Acta. Nishio N., S. Nakai, T. Kogiso, and H.G. Barsczus (2005)Geochem. J. 39, 91-103.

  7. Life cycle, seasonal vertical distribution and feeding of Calanus finmarchicus in Skagerrak coastal water

    Microsoft Academic Search

    U. Båmstedt

    2000-01-01

    Day\\/night zooplankton sampling in Kosterfjorden, Sweden, gave information on population succession, vertical distribution\\u000a and feeding of Calanus finmarchicus over 17 months. Copepodid Stage 1 and 2 (C-I, C-II) were present from December to August, indicating reproduction during\\u000a most of the year. Mating and breeding for the overwintering generation mainly took place in February\\/March, resulting in peak\\u000a abundance of C-I in

  8. Chemical composition and size distribution of airborne particulate matters in Beijing during the 2008 Olympics

    NASA Astrophysics Data System (ADS)

    Li, Xingru; Wang, Lili; Wang, Yuesi; Wen, Tianxue; Yang, Yongjie; Zhao, Yanan; Wang, Yingfeng

    2012-04-01

    Size-segregated aerosol samples were collected daily in Beijing from 1 Jun. to 20 Sep. during the Beijing Olympic Games in 2008 to investigate aerosol concentrations, particle size distributions, and sources as well as the effects of pollution control measures on the chemical compositions (including Water-soluble ions, trace elements, elemental carbon (EC), and organic carbon (OC)) in aerosols of different sizes. Water-soluble ions, EC, OC, and trace elements accounted for 45.0%, 1.6%, 14.7%, and 11.4% of the total particle mass (PM), respectively. Approximately 56%, 56%, 30%, 71% and 55% of the PM, water-soluble ions, trace elements, EC and OC, respectively, were associated with particles smaller than 2.1 ?m. Sulfate, nitrate, and ammonium were the dominant ions, which together accounted for approximately 77% of total water-soluble ions. The crustal elements accounted for the majority of the trace elements present. Different sources showed different mass size distributions. Anthropogenic source compounds, such as sulfate, nitrate, ammonium, OC, EC, and toxic elements, were mainly present in fine mode aerosols, whereas crustal elements, such as Al, Fe, Ca, Mg and Ba, primarily occurred in the coarse mode. SO42- and NH4+ concentrations were strongly correlated (r2 = 0.90, slope = 1.63) in the fine mode, thereby indicating that SO42- was mainly present as (NH4)2SO4; in contrast, a weak correlation between SO42- and NH4+ (r2 = 0.18, slope = 0.54) was observed in the coarse mode, indicating that SO42- was associated with other ions. Similarly, SO42- and NO3- exhibited a stronger correlation in the fine mode than in the coarse mode, indicating that SO42- and NO3- were formed via the same in-cloud processes in fine particles. The OC/EC ratio and the correlations between EC and OC concentrations showed that the sources of carbonaceous species were secondary organic carbon from fine particles and the long-range transport of coarse carbonaceous particles from biomass burning. The concentrations of atmospheric pollutants declined during the 2008 Olympic Games, indicating that the pollution control measures were effective in decreasing particulate air pollution in Beijing.

  9. Computed-tomography scan-based finite element analysis of stress distribution in premolars restored with composite resin

    NASA Astrophysics Data System (ADS)

    Kantardži?, I.; Vasiljevi?, D.; Blaži?, L.; Puškar, T.; Tasi?, M.

    2012-05-01

    Mechanical properties of restorative material have an effect on stress distribution in the tooth structure and the restorative material during mastication. The aim of this study was to investigate the influence of restorative materials with different moduli of elasticity on stress distribution in the three-dimensional (3D) solid tooth model. Computed tomography scan data of human maxillary second premolars were used for 3D solid model generation. Four composite resins with a modulus of elasticity of 6700, 9500, 14?100 and 21?000?MPa were considered to simulate four different clinical direct restoration types. Each model was subjected to a resulting force of 200?N directed to the occlusal surface, and stress distribution and maximal von Mises stresses were calculated using finite-element analysis. We found that the von Mises stress values and stress distribution in tooth structures did not vary considerably with changing the modulus of elasticity of restorative material.

  10. Composites

    NASA Astrophysics Data System (ADS)

    Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-N?dza, A.; Mackiewicz, S.; Dutkiewicz, J.

    2014-11-01

    It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

  11. Monolithic silica with bimodal pore size distribution fabricated by self-separated sol–gel composite materials

    Microsoft Academic Search

    S. Grund; A. Seifert; G. Baumann; W. Baumann; G. Marx; M. Kehr; S. Spange

    2006-01-01

    The sol–gel process of tetraethoxysilane involving the simultaneously occurring cationic polymerization of furfuryl alcohol has been used to fabricate large amounts of monolithic silica having hierarchical bimodal pore size distribution with regular arrayed mesopores. In the key step of the sol–gel polymerization a phase separation on micrometer scale takes place and two different poly(furfuryl alcohol)\\/silica composite material portions are formed.

  12. The effect of a spew fillet on adhesive stress distributions in laminated composite single-lap joints

    Microsoft Academic Search

    J. Morton

    1995-01-01

    A laminated composite single-lap joint without a spew fillet, subjected to tensile loading, is investigated experimentally and numerically. By directly comparing the experimentally- and numerically-determined deformations of the single-lap joints with and without a fillet, the effect of a spew fillet on adhesive stress distributions is discussed. Moiré interferometry is used to measure the in-plane surface deformation of the overlap

  13. Effect of melt-solid interface shape on lateral compositional distribution of unidirectionally solidified 2-6 semiconducting alloys

    NASA Technical Reports Server (NTRS)

    Wang, Jai-Ching

    1996-01-01

    A computer code developed previously has been used to simulate lateral compositional distributions for several 2-6 semiconducting systems. The code is based on analytical results obtained previously. The system under study is an azimuthal symmetric cylindrical system with a curved melt-solid interface shape during an unidirectional solidification process. It is assumed that the system is under a steady state diffusion limited growth condition.

  14. Barely visible impact damage detection for composite sandwich structures by optical-fiber-based distributed strain measurement

    Microsoft Academic Search

    S. Minakuchi; Y. Okabe; T. Mizutani; N. Takeda

    2009-01-01

    The authors developed an impact damage-detection system for large-scale composite sandwich structures using an optical fiber network running throughout the structure. A Brillouin-based sensing system with high spatial resolution (pre-pump pulse Brillouin optical time-domain analysis (PPP-BOTDA)) was utilized for distributed strain measurement. The PPP-BOTDA sensing system can measure axial strain along the optical fiber by employing stimulated Brillouin scattering. The

  15. Source apportionment of ambient fine particle from combined size distribution and chemical composition data during summertime in Beijing

    NASA Astrophysics Data System (ADS)

    Liu, Z. R.; Wang, Y. S.; Liu, Q.; Hu, B.; Sun, Y.

    2013-01-01

    Continuous particle number concentration and chemical composition data were collected over one month during summertime in Beijing to investigate the source apportionment of ambient fine particles. Particle size distributions from 15 nm to 2.5 ?m in diameter and composition data, such as organic matter, sulfate, nitrate, ammonium, chlorine, and gaseous pollutants, were analyzed using positive matrix factorisation (PMF) which indentified eight factors: cooking, solid mode exhaust, nucleation mode exhaust, accumulation mode, secondary nitrate, secondary sulfate, coal-fired power plant and road dust. Nearly two-thirds of particle number concentrations were attributed to cooking (22.8%) and motor vehicle (37.5%), whereas road dust, coal-fired power plant and regional sources contributed 69.0% to particle volume concentrations. Local and remote sources were distinguished using size distributions associated with each factor. Local sources were generally characterised by unimodal or bimodal number distributions, consisting mostly of particles less 0.1 ?m in diameter, and regional sources were defined by mostly accumulation mode particles. Nearly one third of secondary nitrate and secondary sulfate was transported from the surrounding areas of Beijing during study period. Overall the introduction of combination of particle number concentration and chemical composition in PMF model is successful at separating the components and quantifying relative contributions to the particle number and volume population in a complex urban atmosphere.

  16. Life cycle analysis of distributed concentrating solar combined heat and power: economics, global warming potential and water

    NASA Astrophysics Data System (ADS)

    Norwood, Zack; Kammen, Daniel

    2012-12-01

    We report on life cycle assessment (LCA) of the economics, global warming potential and water (both for desalination and water use in operation) for a distributed concentrating solar combined heat and power (DCS-CHP) system. Detailed simulation of system performance across 1020 sites in the US combined with a sensible cost allocation scheme informs this LCA. We forecast a levelized cost of 0.25 kWh-1 electricity and 0.03 kWh-1 thermal, for a system with a life cycle global warming potential of ˜80 gCO2eq kWh-1 of electricity and ˜10 gCO2eq kWh-1 thermal, sited in Oakland, California. On the basis of the economics shown for air cooling, and the fact that any combined heat and power system reduces the need for cooling while at the same time boosting the overall solar efficiency of the system, DCS-CHP compares favorably to other electric power generation systems in terms of minimization of water use in the maintenance and operation of the plant. The outlook for water desalination coupled with distributed concentrating solar combined heat and power is less favorable. At a projected cost of 1.40 m-3, water desalination with DCS-CHP would be economical and practical only in areas where water is very scarce or moderately expensive, primarily available through the informal sector, and where contaminated or salt water is easily available as feed-water. It is also interesting to note that 0.40-1.90 m-3 is the range of water prices in the developed world, so DCS-CHP desalination systems could also be an economical solution there under some conditions.

  17. Spectroscopic study of the Moses Lake dune field, Washington: Determination of compositional distributions and source lithologies

    E-print Network

    Bandfield, Joshua L.

    spectra are composed of three components that represent basalt, granodiorite, and clay compositions. The basalt and granodiorite components are similar to spectra of clast and bedrock samples from the Grand interdune compositional variation, indicating that the basalt and granodiorite components were likely

  18. Thermoelectric figure of merit for bulk nanostructured composites with distributed parameters

    SciTech Connect

    Snarskii, A. A. [National Technical University 'Kyiv Polytechnic Institute' (Ukraine); Sarychev, A. K. [Russian Academy of Sciences, Institute for Theoretical and Applied Electromagnetics (Russian Federation); Bezsudnov, I. V., E-mail: biv@akuan.ru ['Nauka-Service' Scientific and Production Company (Russian Federation); Lagarkov, A. N. [Russian Academy of Sciences, Institute for Theoretical and Applied Electromagnetics (Russian Federation)

    2012-05-15

    The effective properties of composites whose structure includes nanocontacts between bulk-phase macrocrystallites are considered. A model for such a nanostructured composite is constructed. Effective values of the thermoelectric power, thermal and electrical conductivities, and thermoelectric figure of merit are calculated in the mean-field approximation.

  19. Development of Atmospheric Neutral Analyzer for Neutral Mass Composition and Velocity Distribution Measurements in the Upper Atmosphere

    NASA Astrophysics Data System (ADS)

    Shimoyama, M.; Hayashi, A.; Ishiguro, K.; Hirahara, M.; Yau, A. W.

    2012-12-01

    In order to understand the temporal and spatial variability of the ionosphere-thermosphere system, simultaneous measurements of the composition and density of the neutral atmosphere and the velocity distribution of individual species are essential. However, most conventional types of instruments for neutral atmosphere lack the simultaneous capability of measuring neutral atmospheric velocity and resolving neutral mass. We are designing the Atmospheric Neutral Analyzer (ANA) instrument to measure neutral composition and velocity distribution simultaneously in the thermosphere. It is designed to measure the detailed, mass-resolved 2-dimensional velocity distribution of neutral species, and to derive the corresponding density, mass composition, bulk velocity and temperature from the measured distribution. The ANA is comprised of 4 sections; Entrance Aperture (EA), Ion Accelerator (IA), Radio-Frequency Ion Mass Analyzer (MA) and Imaging Particle Detector (PD). The EA consists of a planar aperture slit and deflection electrode, and functions as an incident-particle selector and collimator. A small fraction of the neutral particles is ionized by electron beam. The IA acts as a particle energy selector by accelerating the ionized neutral particles. The MA acts as an ion velocity selector. The radio-frequency voltage is applied to grids and selectively accelerates ions of matching speed. As a result, ions with a particular mass-per-charge are selected. The PD, which is comprised of a retarding grid, micro-channel plate and charge coupled device, detects the mass-selected ions, and a 2-dimensional image of velocity distribution is obtained. We present the detailed design of the ANA in this paper.

  20. Distribution of protein poly(ADP-ribosyl)ation systems across all domains of life

    PubMed Central

    Perina, Dragutin; Miko?, Andreja; Ahel, Josip; ?etkovi?, Helena; Žaja, Roko; Ahel, Ivan

    2014-01-01

    Poly(ADP-ribosyl)ation is a post-translational modification of proteins involved in regulation of many cellular pathways. Poly(ADP-ribose) (PAR) consists of chains of repeating ADP-ribose nucleotide units and is synthesized by the family of enzymes called poly(ADP-ribose) polymerases (PARPs). This modification can be removed by the hydrolytic action of poly(ADP-ribose) glycohydrolase (PARG) and ADP-ribosylhydrolase 3 (ARH3). Hydrolytic activity of macrodomain proteins (MacroD1, MacroD2 and TARG1) is responsible for the removal of terminal ADP-ribose unit and for complete reversion of protein ADP-ribosylation. Poly(ADP-ribosyl)ation is widely utilized in eukaryotes and PARPs are present in representatives from all six major eukaryotic supergroups, with only a small number of eukaryotic species that do not possess PARP genes. The last common ancestor of all eukaryotes possessed at least five types of PARP proteins that include both mono and poly(ADP-ribosyl) transferases. Distribution of PARGs strictly follows the distribution of PARP proteins in eukaryotic species. At least one of the macrodomain proteins that hydrolyse terminal ADP-ribose is also always present. Therefore, we can presume that the last common ancestor of all eukaryotes possessed a fully functional and reversible PAR metabolism and that PAR signalling provided the conditions essential for survival of the ancestral eukaryote in its ancient environment. PARP proteins are far less prevalent in bacteria and were probably gained through horizontal gene transfer. Only eleven bacterial species possess all proteins essential for a functional PAR metabolism, although it is not known whether PAR metabolism is truly functional in bacteria. Several dsDNA viruses also possess PARP homologues, while no PARP proteins have been identified in any archaeal genome. Our analysis of the distribution of enzymes involved in PAR metabolism provides insight into the evolution of these important signalling systems, as well as providing the basis for selection of the appropriate genetic model organisms to study the physiology of the specific human PARP proteins. PMID:24865146

  1. Life span and tissue distribution of 111indium-labeled blood platelets in hypomagnesemic lambs

    SciTech Connect

    Schneider, M.D.; Miller, J.K.; White, P.K.; Ramsey, N.

    1983-05-01

    Circulating platelets may be activated by exposed triple-helical collagen in atherosclerotic lesions in Mg-deficient ruminants. Autologous platelets, labeled in vitro with 111In and determined to be active, were injected into 5 hypomagnesemic and 3 control lambs fed semipurified diets with 100 or 2,000 mg of Mg/kg of feed for 3 months. During the first 68 hours, 111In concentrations were 11 times higher in packed cells than in plasma. Packed-cell 111In increased 60% during the first 2 hours, probably due to initial tissue sequestration and later release of labeled platelets. Thereafter, platelet half-life span averaged 60 and 63 hours for hypomagnesemic and control lambs. After 68 hours, lambs were injected with native vascular collagen fibrils at 500 micrograms/kg of body weight to initiate reversible platelet aggregation. Within 1 minute, 83% of packed-cell 111In disappeared from circulation. Thirty minutes later, the lambs were euthanatized and necropsied and in the lungs, liver, and spleen, 111In averaged 24%, 19%, and 9%, respectively, of 111In injected 68 hours earlier. Organ deposits were not affected by Mg intake, but 111In in the lungs was somewhat lower in 2 lambs injected with inactivated collagen. Pathologic changes induced by reversible platelet aggregation were compatible with right ventricular failure complicated by pulmonary edema, similar to changes in hypomagnesemic lambs that died spontaneously. Platelets in blood exposed to vascular lesions in hypomagnesemic ruminants could be a major mortality risk factor in grass tetany disease.

  2. S3QL: A distributed domain specific language for controlled semantic integration of life sciences data

    PubMed Central

    2011-01-01

    Background The value and usefulness of data increases when it is explicitly interlinked with related data. This is the core principle of Linked Data. For life sciences researchers, harnessing the power of Linked Data to improve biological discovery is still challenged by a need to keep pace with rapidly evolving domains and requirements for collaboration and control as well as with the reference semantic web ontologies and standards. Knowledge organization systems (KOSs) can provide an abstraction for publishing biological discoveries as Linked Data without complicating transactions with contextual minutia such as provenance and access control. We have previously described the Simple Sloppy Semantic Database (S3DB) as an efficient model for creating knowledge organization systems using Linked Data best practices with explicit distinction between domain and instantiation and support for a permission control mechanism that automatically migrates between the two. In this report we present a domain specific language, the S3DB query language (S3QL), to operate on its underlying core model and facilitate management of Linked Data. Results Reflecting the data driven nature of our approach, S3QL has been implemented as an application programming interface for S3DB systems hosting biomedical data, and its syntax was subsequently generalized beyond the S3DB core model. This achievement is illustrated with the assembly of an S3QL query to manage entities from the Simple Knowledge Organization System. The illustrative use cases include gastrointestinal clinical trials, genomic characterization of cancer by The Cancer Genome Atlas (TCGA) and molecular epidemiology of infectious diseases. Conclusions S3QL was found to provide a convenient mechanism to represent context for interoperation between public and private datasets hosted at biomedical research institutions and linked data formalisms. PMID:21756325

  3. Design for cyclic loading endurance of composites

    NASA Astrophysics Data System (ADS)

    Shiao, Michael C.; Murthy, Pappu L. N.

    The present paper describes the application of the computer code IPACS (Integrated Probabilistic Assessment of Composite Structures) to air craft wing type structures. The code performs a complete probabilistic structural analysis for composites taking into account the uncertainties in geometry, boundary conditions, material properties, laminate lay-ups and loads. Results of the analysis are presented in terms of cumulative distribution functions (CDF) and probability density function (PDF) of life of a wing type composite structure under different hygrothermal environments subjected to random pressure. The sensitivity of fatigue life to a number of critical structural/material variables is also computed from the analysis.

  4. Design for cyclic loading endurance of composites

    NASA Astrophysics Data System (ADS)

    Shiao, Michael C.; Murthy, Pappu L. N.; Chamis, Christos C.; Liaw, Leslie D. G.

    1993-12-01

    The application of the computer code IPACS (Integrated Probabilistic Assessment of Composite Structures) to aircraft wing type structures is described. The code performs a complete probabilistic analysis for composites taking into account the uncertainties in geometry, boundary conditions, material properties, laminate lay-ups, and loads. Results of the analysis are presented in terms of cumulative distribution functions (CDF) and probability density function (PDF) of the fatigue life of a wing type composite structure under different hygrothermal environments subjected to the random pressure. The sensitivity of the fatigue life to a number of critical structural/material variables is also computed from the analysis.

  5. Exclusive Breastfeeding and Other Foods in the First Six Months of Life: Effects on Nutritional Status and Body Composition of Brazilian Children

    PubMed Central

    Magalhães, Taís C. A.; Vieira, Sarah A.; Priore, Silvia E.; Ribeiro, Andréia Q.; Lamounier, Joel A.; Franceschini, Sylvia C. C.; Sant'Ana, Luciana F. R.

    2012-01-01

    Objective. To evaluate the effect of exclusive breastfeeding and consumption of other foods in the first six months of life in the nutritional status and body composition of children. Methods. A retrospective cohort study with 185 children aged from 4 to 7 years was monitored during the first months of life in a program of support to breastfeeding. We evaluated weight, height, waist circumference, and body composition by using DEXA. The nutritional status was assessed by the BMI/age index. The parameters of adiposity were classified by using as the cutoff point, the 85th percentile of the sample itself, according to gender and age. Confounding factors considered were variables related to maternal, pregnancy, birth, sociodemographic, health, lifestyle, and diet. Bivariate and multivariate analyses were performed, the latter by means of multiple logistic regression. Results. The median exclusive breastfeeding was 3 months. Of the children, 42.7% received cow's milk and 35.7% received infant formula. Regarding nutritional status, 21.1% of the children showed changes. The variables of infant feeding were not independently associated with nutritional status and body composition of the children and there were no differences between the groups studied. Conclusion. Breastfeeding was not a protective factor to overweight and body fat in children. PMID:23193378

  6. Decapod crustacean larval communities in the Balearic Sea (western Mediterranean): Seasonal composition, horizontal and vertical distribution patterns

    NASA Astrophysics Data System (ADS)

    Torres, Asvin P.; Dos Santos, Antonina; Balbín, Rosa; Alemany, Francisco; Massutí, Enric; Reglero, Patricia

    2014-10-01

    Decapod crustaceans are the main target species of deep water bottom trawl fisheries in the Balearic Sea but little is known about their larval stages. This work focuses on the species composition of the decapod larval community, describing the main spatio-temporal assemblages and assessing their vertical distribution. Mesozooplankton sampling was carried out using depth-stratified sampling devices at two stations located over the shelf break and the mid slope, in the north-western and southern Mallorca in late autumn 2009 and summer 2010. Differences among decapod larvae communities, in terms of composition, adult's habitat such as pelagic or benthic, and distribution patterns were observed between seasons, areas and station. Results showed that for both seasons most species and developmental stages aggregated within the upper water column (above 75 m depth) and showed higher biodiversity in summer compared to late autumn. Most abundant species were pelagic prawns (e.g., Sergestidae) occurring in both seasons and areas. The larval assemblages' distributions were different between seasonal hydrographic scenarios and during situations of stratified and non-stratified water column. The vertical distribution patterns of different larval developmental stages in respect to the adult's habitat were analyzed in relation to environmental variables. Fluorescence had the highest explanatory power. Four clearly different vertical patterns were identified: two corresponding to late autumn, which were common for all the main larval groups and other two in summer, one corresponding to larvae of coastal benthic and the second to pelagic species larvae.

  7. Turning the Analysis of Obesity-Mortality Associations Upside Down: Modeling Years of Life Lost Through Conditional Distributions

    PubMed Central

    Robertson, Henry T.; de los Campos, Gustavo; Allison, David B.

    2012-01-01

    The analysis of longevity as a function of risk factors such as body mass index (BMI; kg/m2), activity levels, and dietary factors is a mainstay of obesity research. Modeling survival through hazard functions, relative risks, or odds of dying with methods such as Cox proportional hazards or logistic regression are the most common approaches and have many advantages. However, they also have disadvantages in terms of the ease of interpretability, especially for non-statisticians; the need for additional data to convert parameter estimates to estimates of years of life lost (YLL); and debates about the appropriate time scale in the model. Parametric survival models are able to provide more direct answers, and in our analysis of an obesity-related data set, gave consistent YLL estimates regardless of the distribution used. Additionally, we offer alternative approaches to the analyses of censored survival data including a modified or ‘compressed’ Gaussian distribution. We therefore recommend increased consideration of parametric survival models in chronic disease and risk factor epidemiology. PMID:23404823

  8. Mesoscale distribution and community composition of zooplankton in the Mozambique Channel

    NASA Astrophysics Data System (ADS)

    Huggett, Jenny A.

    2014-02-01

    Recent studies have shown the Mozambique Channel to exhibit high mesoscale variability, but how mesoscale features influence the zooplankton community in this region is not known. The biovolume, biomass, vertical distribution and community composition of mesozooplankton (>200 µm) associated with mesoscale eddies in the Mozambique Channel was investigated during four cruises in September 2007, December 2008, November 2009 and April/May 2010. Stations were categorized according to their location in cyclonic (cold-core) or anticyclonic (warm-core) eddies, frontal, divergence or shelf regions. Mean mesozooplankton biovolume in the upper 200 m was 0.33 ml m-3, with zooplankton largely concentrated in the upper 100 m during all four cruises (weighted mean depth=66.6 m). Sampling depth was the most important predictor of biovolume, which was greatest for net samples with a mid-depth of 0-40 m, but declined deeper in the water column. Biovolume at the shelf (0.37 ml m-3), divergence and cyclonic eddy stations (0.31 ml m-3) was significantly greater than at frontal and anticyclonic eddy stations (0.20 ml m-3). Mean biovolume was significantly higher during 2008 and 2010 compared to 2007 and 2009, and was also significantly higher for samples collected at night (and twilight) than during the day. The mesozooplankton community in 2007 was strongly dominated by small copepods (~70-80% abundance) followed by appendicularians (10%), ostracods (8%) and chaetognaths (7%). The most abundant copepods were the Paracalanids, Oncaea spp., Oithona spp. and Corycaeus spp. Multivariate analysis showed that the communities in 2007 and 2008 were most strongly structured by depth, but classification (cyclonic/anticyclonic) was also important in 2007 when mesoscale features were more strongly developed. Zooplankton assemblages showed a high degree of homogeneity, with differences between mesoscale features largely due to differing abundances of similar taxa. These observations suggest that mesoscale eddy and shelf interactions play a fundamental role in shaping the Mozambique Channel pelagic ecosystem through the concentration, enhanced growth and redistribution of zooplankton communities. Although frontal areas between eddies were poor in zooplankton biomass, the extensive inter-eddy divergence areas were as rich in biomass as the small cyclonic eddy core regions. These patterns are important for understanding the favorability of observed foraging areas for higher trophic levels.

  9. Simultaneous deconvolution of the bivariate distribution of molecular weight and chemical composition of polyolefins made with ziegler-natta catalysts.

    PubMed

    Alghyamah, Abdulaziz A; Soares, João B P

    2009-02-18

    Polyolefins made with Ziegler-Natta catalysts have non-uniform distributions of molecular weight (MWD) and chemical composition (CCD). The MWD is usually measured by high-temperature gel permeation chromatography (GPC) and the CCD by either temperature rising elution fractionation (TREF) or crystallization analysis fractionation (CRYSTAF). A mathematical model is needed to quantify the information provided by these analytical techniques and to relate it to the presence of multiple site types on Ziegler-Natta catalysts. We developed a robust computer algorithm to deconvolute the MWD and CCD of polyolefins simultaneously using Flory's most probable distribution and the cumulative CCD component of Stockmayer's distribution, which includes the soluble fraction commonly present in linear low-density polyethylene (LLDPE) resins and have applied this procedure for the first time to several industrial LLDPE resins. The deconvolution results are reproducible and consistent with theoretical expectations. PMID:21706614

  10. Adaptive component composition and load balancing for distributed stream processing applications

    Microsoft Academic Search

    Thomas Repantis; Yannis Drougas; Vana Kalogeraki

    2009-01-01

    Providing real-time and QoS support to stream processing applications running on top of large-scale overlays is challenging\\u000a due to the inherent heterogeneity and resource limitations of the nodes and the multiple QoS demands of the applications that\\u000a must concurrently be met. In this paper we propose an integrated adaptive component composition and load balancing mechanism\\u000a that (1) allows the composition

  11. Seasonal distribution and fatty acid composition of littoral microalgae in the Yenisei River

    Microsoft Academic Search

    Nadezhda N. Sushchik; Michail I. Gladyshev; Elena A. Ivanova; Elena S. Kravchuk

    2010-01-01

    We studied fatty acid (FA) composition of littoral microalgae in the fast-flowing oligotrophic river, the Yenisei, Siberia,\\u000a monthly for 3 years. Seasonal dynamics of species composition had similar patterns in all the studied years. In springs, a\\u000a pronounced dominance of filamentous green algae occurred, in summer and autumn diatoms were abundant, and in late autumn and\\u000a winter epilithic biofilms consisted primarily

  12. Investigation of the Composition and Electromagnetic Properties of Lithium Ferrite LiFe5O8 Ceramics Synthesized from Ultradisperse Iron Oxide

    NASA Astrophysics Data System (ADS)

    Surzhikov, A. P.; Lysenko, E. N.; Malyshev, A. V.; Nikolaev, E. V.; Zhuravkov, S. P.; Vlasov, V. A.

    2015-02-01

    Structural, magnetic, and electric characteristics of LiFe5O8 synthesized from ultradisperse iron oxide powder are investigated. The basic Fe2O3 reagent is prepared by oxidation of iron nanopowder with particle sizes of 100 nm synthesized by the electroexplosive method. It is demonstrated that LiFe5O8 is characterized by fine-grained ceramic structure with average grain size of 1.4 ?m, high values of the Curie temperature (~630°C), specific electrical resistance (107 ??cm), and saturation magnetization (>3300 G). Thus, lithium ferrite so obtained without additives has the parameters suitable for its application as a microwave ferrite material. It is also demonstrated that addition of bismuth ferrite to the lithium ferrite composition during its sintering yields lower values of the specific electrical resistance and relatively high values of the density and saturation magnetization.

  13. Effects of martial arts exercise on body composition, serum biomarkers and quality of life in overweight/obese premenopausal women: a pilot study.

    PubMed

    Chyu, Ming-Chien; Zhang, Yan; Brismée, Jean-Michel; Dagda, Raul Y; Chaung, Eugene; Von Bergen, Vera; Doctolero, Susan; Shen, Chwan-Li

    2013-01-01

    Various exercise interventions have been shown to benefit weight control and general health in different populations. However, very few studies have been conducted on martial arts exercise (MAE). The objective of this pilot study is to evaluate the efficacy of 12 weeks of MAE intervention on body composition, serum biomarkers and quality of life (QOL) in overweight/obese premenopausal women. We found that subjects in the MAE group did not lose body weight, while they significantly decreased fat-free mass and muscle mass as compared to those in the control group, who demonstrated an increase in these parameters. The MAE group demonstrated an increase in serum IGF-I concentration, but no change in others. MAE may be a feasible and effective approach to improve body composition and QOL in overweight/obese premenopausal women. Our study underscores the need for further studies using larger samples to establish possible benefits of MAE in various populations. PMID:24665215

  14. Effect of re-melting on particle distribution and interface formation in SiC reinforced 2124Al matrix composite

    SciTech Connect

    Mandal, Durbadal, E-mail: durbadal73@yahoo.co.in [MEF Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007 (India); Viswanathan, Srinath [Dept of Metallurgical and Materials Engineering, University of Alabama, Tuscaloosa, AL (United States)

    2013-12-15

    The interface between metal matrix and ceramic reinforcement particles plays an important role in improving properties of the metal matrix composites. Hence, it is important to find out the interface structure of composite after re-melting. In the present investigation, the 2124Al matrix with 10 wt.% SiC particle reinforced composite was re-melted at 800 °C and 900 °C for 10 min followed by pouring into a permanent mould. The microstructures reveal that the SiC particles are distributed throughout the Al-matrix. The volume fraction of SiC particles varies from top to bottom of the composite plate and the difference increases with the decrease of re-melting temperature. The interfacial structure of re-melted 2124Al–10 wt.%SiC composite was investigated using scanning electron microscopy, an electron probe micro-analyzer, a scanning transmission electron detector fitted with scanning electron microscopy and an X-ray energy dispersive spectrometer. It is found that a thick layer of reaction product is formed at the interface of composite after re-melting. The experimental results show that the reaction products at the interface are associated with high concentration of Cu, Mg, Si and C. At re-melting temperature, liquid Al reacts with SiC to form Al{sub 4}C{sub 3} and Al–Si eutectic phase or elemental Si at the interface. High concentration of Si at the interface indicates that SiC is dissociated during re-melting. The X-ray energy dispersive spectrometer analyses confirm that Mg- and Cu-enrich phases are formed at the interface region. The Mg is segregated at the interface region and formed MgAl{sub 2}O{sub 4} in the presence of oxygen. The several elements identified at the interface region indicate that different types of interfaces are formed in between Al matrix and SiC particles. The Al–Si eutectic phase is formed around SiC particles during re-melting which restricts the SiC dissolution. - Highlights: • Re-melted composite shows homogeneous particle distribution • Thick reaction products are observed at the interface • Carbide is identified at interface due to SiC dissolution at high temperature • Reaction products are also Si enrich phase • Mg and Cu segregated and formed MgAl{sub 2}O{sub 4}, CuMgAl{sub 2} phase at grain boundary.

  15. Stress-rupture life and strength retention of an aramid fiber\\/epoxy composite under accelerating conditions

    Microsoft Academic Search

    L. Penn; R. J. Sherry

    1977-01-01

    The long-term tensile strength retention of Kevlar 49 (aramid fiber)\\/epoxy composite under sustained loading at 56.4 percent of the ultimate fiber tensile strength (3400 MPa) was studied to evaluate the lifetime to failure of the composite under the same load level. To obtain data in a conveniently short time, elevated temperature was used according to an acceleration relation (Arrhenius type)

  16. Abundance, composition, and distribution of crustacean zooplankton in relation to hypolimnetic oxygen depletion in west-central Lake Erie

    USGS Publications Warehouse

    Heberger, Roy F.; Reynolds, James B.

    1977-01-01

    Samples of crustacean zooplankton were collected monthly in west-central Lake Erie in April and June to October 1968, and in July and August 1970, before and during periods of hypolimnetic dissolved oxygen (DO) depletion. The water column at offshore stations was thermally stratified from June through September 1968, and the hypolimnion contained no DO in mid-August of 1968 or 1970. Composition, abundance, and vertical distribution of crustacean zooplankton changed coincidentally with oxygen depletion. From July to early August, zooplankton abundance dropped 79% in 1968 and 50% in 1970. The declines were attributed largely to a sharp decrease in abundance of planktonic Cyclops bicuspidatus thomasi. Zooplankton composition shifted from mainly cyclopoid copepods in July to mainly cladocerans and copepod nauplii in middle to late August. We believe that mortality of adults and dormancy of copepodites in response to anoxia was the probable reason for the late summer decline in planktonic C. b. thomasi.

  17. Controlling the length scale and distribution of the ductile phase in metallic glass composites through friction stir processing

    NASA Astrophysics Data System (ADS)

    Singh Arora, Harpreet; Mridha, Sanghita; Singh Grewal, Harpreet; Singh, Harpreet; Hofmann, Douglas C.; Mukherjee, Sundeep

    2014-06-01

    We demonstrate the refinement and uniform distribution of the crystalline dendritic phase by friction stir processing (FSP) of titanium based in situ ductile-phase reinforced metallic glass composite. The average size of the dendrites was reduced by almost a factor of five (from 24 ?m to 5 ?m) for the highest tool rotational speed of 900 rpm. The large inter-connected dendrites become more fragmented with increased circularity after processing. The changes in thermal characteristics were measured by differential scanning calorimetry. The reduction in crystallization enthalpy after processing suggests partial devitrification due to the high strain plastic deformation. FSP resulted in increased hardness and modulus for both the amorphous matrix and the crystalline phase. This is explained by interaction of shear bands in amorphous matrix with the strain-hardened dendritic phase. Our approach offers a new strategy for microstructural design in metallic glass composites.

  18. How Rocky Are They? The Composition Distribution of Kepler's Sub-Neptune Planet Candidates within 0.15 AU

    E-print Network

    Wolfgang, Angie

    2014-01-01

    The Kepler Mission has found thousands of planetary candidates with radii between 1 and 4 R$_\\oplus$. These planets have no analogues in our own Solar System, providing an unprecedented opportunity to understand the range and distribution of planetary compositions allowed by planet formation and evolution. A precise mass measurement is usually required to constrain the possible composition of an individual super-Earth-sized planet, but these measurements are difficult and expensive to make for the majority of Kepler planet candidates. Fortunately, adopting a statistical approach helps us to address this question without them. In particular, we apply hierarchical Bayesian modeling to a subsample of Kepler planet candidates that is complete for $P1.2$ R$_\\oplus$ and draw upon interior structure models which yield radii largely independent of mass by accounting for the thermal evolution of a gaseous envelope around a rocky core. Assuming the envelope is dominated by hydrogen and helium, we present the current-da...

  19. Long-Lasting Effects of Early-Life Antibiotic Treatment and Routine Animal Handling on Gut Microbiota Composition and Immune System in Pigs

    PubMed Central

    Schokker, Dirkjan; Zhang, Jing; Vastenhouw, Stéphanie A.; Heilig, Hans G. H. J.; Smidt, Hauke; Rebel, Johanna M. J.; Smits, Mari A.

    2015-01-01

    Background In intensive pig husbandry systems, antibiotics are frequently administrated during early life stages to prevent respiratory and gastro-intestinal tract infections, often in combination with stressful handlings. The immediate effects of these treatments on microbial colonization and immune development have been described recently. Here we studied whether the early life administration of antibiotics has long-lasting effects on the pig’s intestinal microbial community and on gut functionality. Methodology/Principal Findings To investigate the long-lasting effect of early-life treatment, piglets were divided into three different groups receiving the following treatments: 1) no antibiotics and no stress, 2) antibiotics and no stress, and 3) antibiotics and stress. All treatments were applied at day four after birth. Sampling of jejunal content for community scale microbiota analysis, and jejunal and ileal tissue for genome-wide transcription profiling, was performed at day 55 (~8 weeks) and day 176 (~25 weeks) after birth. Antibiotic treatment in combination with or without exposure to stress was found to have long-lasting effects on host intestinal gene expression involved in a multitude of processes, including immune related processes. Conclusions/Significance The results obtained in this study indicate that early life (day 4 after birth) perturbations have long-lasting effects on the gut system, both in gene expression (day 55) as well as on microbiota composition (day 176). At day 55 high variance was observed in the microbiota data, but no significant differences between treatment groups, which is most probably due to the newly acquired microbiota during and right after weaning (day 28). Based on the observed difference in gene expression at day 55, it is hypothesized that due to the difference in immune programming during early life, the systems respond differently to the post-weaning newly acquired microbiota. As a consequence, the gut systems of the treatment groups develop into different homeostasis. PMID:25658611

  20. Study on Distribution and Composition of Carboxylic Acids of Bohai Crude Oil in China

    Microsoft Academic Search

    Bangfeng Qi; Xu Fei; Shaojun Wang; Liren Chen

    2004-01-01

    This study concerns the distribution, type, and structure of carboxylic acids in the 200–550°C distillates of Bohai crude oil. The acids, isolated by aqueous alcoholic sodium hydroxide, were converted into corresponding methyl esters with BF3 as a catalyst. The chemical structure of these carboxylic acids and distribution of their various components in different distillates were studied in detail by IR,

  1. Composition and Distribution of Cell Wall Phenolic Compounds in Flax ( Linum usitatissimum L.) Stem Tissues

    Microsoft Academic Search

    T. A. Gorshkova; V. V. Salnikov; N. M. Pogodina; S. B. Chemikosova; E. V. Yablokova; A. V. Ulanov; M. V. Ageeva; J. E. G. van Dam; V. V. Lozovaya

    2000-01-01

    Cell wall phenolic compounds were analysed in xylem and bast fibre-rich peels of flax stems by biochemical, histochemical and ultrastructural approaches. Localization of cell wall phenolics by the enzyme-gold method using laccase revealed several gold particle distribution patterns. One of the major types (an even distribution of single gold particles) was present mainly in xylem, while the other (compact branched

  2. Measurement of dijet angular distributions and search for quark compositeness in pp collisions at ?s = 7 TeV.

    PubMed

    Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Erö, J; Fabjan, C; Friedl, M; Frühwirth, R; Ghete, V M; Hammer, J; Hänsel, S; Hartl, C; Hoch, M; Hörmann, N; Hrubec, J; Jeitler, M; Kasieczka, G; Kiesenhofer, W; Krammer, M; Liko, D; Mikulec, I; Pernicka, M; Rohringer, H; Schöfbeck, R; Strauss, J; Taurok, A; Teischinger, F; Wagner, P; Waltenberger, W; Walzel, G; Widl, E; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Benucci, L; Cerny, K; De Wolf, E A; Janssen, X; Maes, T; Mucibello, L; Ochesanu, S; Roland, B; Rougny, R; Selvaggi, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Beauceron, S; Blekman, F; Blyweert, S; D'Hondt, J; Devroede, O; Gonzalez Suarez, R; Kalogeropoulos, A; Maes, J; Maes, M; Tavernier, S; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Villella, I; Charaf, O; Clerbaux, B; De Lentdecker, G; Dero, V; Gay, A P R; Hammad, G H; Hreus, T; Marage, P E; Thomas, L; Vander Velde, C; Vanlaer, P; Wickens, J; Adler, V; Costantini, S; Grunewald, M; Klein, B; Marinov, A; McCartin, J; Ryckbosch, D; Thyssen, F; Tytgat, M; Vanelderen, L; Verwilligen, P; Walsh, S; Zaganidis, N; Basegmez, S; Bruno, G; Caudron, J; Ceard, L; De Favereau De Jeneret, J; Delaere, C; Demin, P; Favart, D; Giammanco, A; Grégoire, G; Hollar, J; Lemaitre, V; Liao, J; Militaru, O; Ovyn, S; Pagano, D; Pin, A; Piotrzkowski, K; Schul, N; Beliy, N; Caebergs, T; Daubie, E; Alves, G A; De Jesus Damiao, D; Pol, M E; Souza, M H G; Carvalho, W; Da Costa, E M; De Oliveira Martins, C; Fonseca De Souza, S; Mundim, L; Nogima, H; Oguri, V; Prado Da Silva, W L; Santoro, A; Silva Do Amaral, S M; Sznajder, A; Torres Da Silva De Araujo, F; Dias, F A; Dias, M A F; Fernandez Perez Tomei, T R; Gregores, E M; Marinho, F; Novaes, S F; Padula, Sandra S; Darmenov, N; Dimitrov, L; Genchev, V; Iaydjiev, P; Piperov, S; Rodozov, M; Stoykova, S; Sultanov, G; Tcholakov, V; Trayanov, R; Vankov, I; Dyulendarova, M; Hadjiiska, R; Kozhuharov, V; Litov, L; Marinova, E; Mateev, M; Pavlov, B; Petkov, P; Bian, J G; Chen, G M; Chen, H S; Jiang, C H; Liang, D; Liang, S; Wang, J; Wang, J; Wang, X; Wang, Z; Xu, M; Yang, M; Zang, J; Zhang, Z; Ban, Y; Guo, S; Guo, Y; Li, W; Mao, Y; Qian, S J; Teng, H; Zhang, L; Zhu, B; Zou, W; Cabrera, A; Gomez Moreno, B; Ocampo Rios, A A; Osorio Oliveros, A F; Sanabria, J C; Godinovic, N; Lelas, D; Lelas, K; Plestina, R; Polic, D; Puljak, I; Antunovic, Z; Dzelalija, M; Brigljevic, V; Duric, S; Kadija, K; Morovic, S; Attikis, A; Galanti, M; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Rykaczewski, H; Finger, M; Finger, M; Assran, Y; Mahmoud, M A; Hektor, A; Kadastik, M; Kannike, K; Müntel, M; Raidal, M; Rebane, L; Azzolini, V; Eerola, P; Czellar, S; Härkönen, J; Heikkinen, A; Karimäki, V; Kinnunen, R; Klem, J; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Ungaro, D; Wendland, L; Banzuzi, K; Korpela, A; Tuuva, T; Sillou, D; Besancon, M; Choudhury, S; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Ferri, F; Ganjour, S; Gentit, F X; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Malcles, J; Marionneau, M; Millischer, L; Rander, J; Rosowsky, A; Shreyber, I; Titov, M; Verrecchia, P; Baffioni, S; Beaudette, F; Bianchini, L; Bluj, M; Broutin, C; Busson, P; Charlot, C; Dahms, T; Dobrzynski, L; Granier de Cassagnac, R; Haguenauer, M; Miné, P; Mironov, C; Ochando, C; Paganini, P; Sabes, D; Salerno, R; Sirois, Y; Thiebaux, C; Wyslouch, B; Zabi, A; Agram, J-L; Andrea, J; Besson, A; Bloch, D; Bodin, D; Brom, J-M; Cardaci, M; Chabert, E C; Collard, C; Conte, E; Drouhin, F; Ferro, C; Fontaine, J-C; Gelé, D; Goerlach, U; Greder, S; Juillot, P; Karim, M; Le Bihan, A-C; Mikami, Y; Van Hove, P; Fassi, F; Mercier, D; Baty, C; Beaupere, N; Bedjidian, M; Bondu, O; Boudoul, G; Boumediene, D; Brun, H; Chanon, N; Chierici, R; Contardo, D; Depasse, P; El Mamouni, H; Falkiewicz, A; Fay, J; Gascon, S; Ille, B; Kurca, T; Le Grand, T; Lethuillier, M; Mirabito, L; Perries, S; Sordini, V; Tosi, S; Tschudi, Y; Verdier, P; Xiao, H; Megrelidze, L; Roinishvili, V; Lomidze, D; Anagnostou, G; Edelhoff, M; Feld, L; Heracleous, N; Hindrichs, O; Jussen, R; Klein, K; Merz, J; Mohr, N; Ostapchuk, A; Perieanu, A; Raupach, F; Sammet, J; Schael, S; Sprenger, D; Weber, H; Weber, M; Wittmer, B; Ata, M; Bender, W; Erdmann, M; Frangenheim, J; Hebbeker, T; Hinzmann, A; Hoepfner, K; Hof, C; Klimkovich, T; Klingebiel, D; Kreuzer, P; Lanske, D; Magass, C; Masetti, G; Merschmeyer, M; Meyer, A; Papacz, P; Pieta, H; Reithler, H; Schmitz, S A; Sonnenschein, L; Steggemann, J; Teyssier, D; Bontenackels, M; Davids, M; Duda, M; Flügge, G; Geenen, H; Giffels, M; Haj Ahmad, W; Heydhausen, D; Kress, T; Kuessel, Y; Linn, A; Nowack, A; Perchalla, L; Pooth, O; Rennefeld, J; Sauerland, P; Stahl, A; Thomas, M

    2011-05-20

    Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at ?s = 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 pb?¹. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of ?? = 5.6 TeV (?? = 6.7 TeV) for destructive (constructive) interference is obtained at the 95% confidence level. PMID:21668222

  3. Measurement of Dijet Angular Distributions and Search for Quark Compositeness in pp Collisions at s=7TeV

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Fabjan, C.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hammer, J.; Hänsel, S.; Hartl, C.; Hoch, M.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kasieczka, G.; Kiesenhofer, W.; Krammer, M.; Liko, D.; Mikulec, I.; Pernicka, M.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Teischinger, F.; Wagner, P.; Waltenberger, W.; Walzel, G.; Widl, E.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Benucci, L.; Cerny, K.; de Wolf, E. A.; Janssen, X.; Maes, T.; Mucibello, L.; Ochesanu, S.; Roland, B.; Rougny, R.; Selvaggi, M.; van Haevermaet, H.; van Mechelen, P.; van Remortel, N.; Beauceron, S.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Devroede, O.; Gonzalez Suarez, R.; Kalogeropoulos, A.; Maes, J.; Maes, M.; Tavernier, S.; van Doninck, W.; van Mulders, P.; van Onsem, G. P.; Villella, I.; Charaf, O.; Clerbaux, B.; de Lentdecker, G.; Dero, V.; Gay, A. P. R.; Hammad, G. H.; Hreus, T.; Marage, P. E.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wickens, J.; Adler, V.; Costantini, S.; Grunewald, M.; Klein, B.; Marinov, A.; McCartin, J.; Ryckbosch, D.; Thyssen, F.; Tytgat, M.; Vanelderen, L.; Verwilligen, P.; Walsh, S.; Zaganidis, N.; Basegmez, S.; Bruno, G.; Caudron, J.; Ceard, L.; de Favereau de Jeneret, J.; Delaere, C.; Demin, P.; Favart, D.; Giammanco, A.; Grégoire, G.; Hollar, J.; Lemaitre, V.; Liao, J.; Militaru, O.; Ovyn, S.; Pagano, D.; Pin, A.; Piotrzkowski, K.; Schul, N.; Beliy, N.; Caebergs, T.; Daubie, E.; Alves, G. A.; de Jesus Damiao, D.; Pol, M. E.; Souza, M. H. G.; Carvalho, W.; da Costa, E. M.; de Oliveira Martins, C.; Fonseca de Souza, S.; Mundim, L.; Nogima, H.; Oguri, V.; Prado da Silva, W. L.; Santoro, A.; Silva Do Amaral, S. M.; Sznajder, A.; Torres da Silva de Araujo, F.; Dias, F. A.; Dias, M. A. F.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Marinho, F.; Novaes, S. F.; Padula, Sandra S.; Darmenov, N.; Dimitrov, L.; Genchev, V.; Iaydjiev, P.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Tcholakov, V.; Trayanov, R.; Vankov, I.; Dyulendarova, M.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Marinova, E.; Mateev, M.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Jiang, C. H.; Liang, D.; Liang, S.; Wang, J.; Wang, J.; Wang, X.; Wang, Z.; Xu, M.; Yang, M.; Zang, J.; Zhang, Z.; Ban, Y.; Guo, S.; Guo, Y.; Li, W.; Mao, Y.; Qian, S. J.; Teng, H.; Zhang, L.; Zhu, B.; Zou, W.; Cabrera, A.; Gomez Moreno, B.; Ocampo Rios, A. A.; Osorio Oliveros, A. F.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Lelas, K.; Plestina, R.; Polic, D.; Puljak, I.; Antunovic, Z.; Dzelalija, M.; Brigljevic, V.; Duric, S.; Kadija, K.; Morovic, S.; Attikis, A.; Galanti, M.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Rykaczewski, H.; Finger, M.; Finger, M., Jr.; Assran, Y.; Mahmoud, M. A.; Hektor, A.; Kadastik, M.; Kannike, K.; Müntel, M.; Raidal, M.; Rebane, L.; Azzolini, V.; Eerola, P.; Czellar, S.; Härkönen, J.; Heikkinen, A.; Karimäki, V.; Kinnunen, R.; Klem, J.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Ungaro, D.; Wendland, L.; Banzuzi, K.; Korpela, A.; Tuuva, T.; Sillou, D.; Besancon, M.; Choudhury, S.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Ferri, F.; Ganjour, S.; Gentit, F. X.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Marionneau, M.; Millischer, L.; Rander, J.; Rosowsky, A.; Shreyber, I.; Titov, M.; Verrecchia, P.; Baffioni, S.; Beaudette, F.; Bianchini, L.; Bluj, M.; Broutin, C.; Busson, P.; Charlot, C.; Dahms, T.; Dobrzynski, L.; Granier de Cassagnac, R.; Haguenauer, M.; Miné, P.; Mironov, C.; Ochando, C.; Paganini, P.; Sabes, D.; Salerno, R.; Sirois, Y.; Thiebaux, C.; Wyslouch, B.; Zabi, A.; Agram, J.-L.; Andrea, J.; Besson, A.; Bloch, D.; Bodin, D.; Brom, J.-M.; Cardaci, M.; Chabert, E. C.; Collard, C.; Conte, E.; Drouhin, F.; Ferro, C.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Greder, S.; Juillot, P.; Karim, M.; Le Bihan, A.-C.; Mikami, Y.; van Hove, P.; Fassi, F.; Mercier, D.; Baty, C.; Beaupere, N.; Bedjidian, M.; Bondu, O.; Boudoul, G.; Boumediene, D.; Brun, H.; Chanon, N.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Falkiewicz, A.; Fay, J.; Gascon, S.; Ille, B.; Kurca, T.; Le Grand, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Sordini, V.; Tosi, S.; Tschudi, Y.; Verdier, P.; Xiao, H.; Megrelidze, L.; Roinishvili, V.; Lomidze, D.; Anagnostou, G.; Edelhoff, M.; Feld, L.; Heracleous, N.; Hindrichs, O.; Jussen, R.; Klein, K.; Merz, J.; Mohr, N.; Ostapchuk, A.; Perieanu, A.; Raupach, F.; Sammet, J.; Schael, S.; Sprenger, D.; Weber, H.; Weber, M.; Wittmer, B.; Ata, M.; Bender, W.; Erdmann, M.

    2011-05-01

    Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at s=7TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36pb-1. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of ?+=5.6TeV (?-=6.7TeV) for destructive (constructive) interference is obtained at the 95% confidence level.

  4. Monte Carlo Simulation of Thermal Conductivity in Randomly Distributed Nanowire Composites

    NASA Astrophysics Data System (ADS)

    Tian, W.; Yang, R.

    2007-03-01

    In this paper, we investigated the thermal conductivity of composites made of two types of randomly stacked nanowires with high contrast ratio of bulk thermal conductivity. Thermal conductivity predictions based on solving the phonon Boltzmann transport equation by using the Monte Carlo method are presented for different contrast ratios of thermal conductivity, sizes of nanowires and the volumetric fractions in the composites. For composites made of nanowires with high contrast ratio thermal conductivity, the thermal conductivity of the nanocomposites increase dramatically when the volumetric fraction of high thermal conductivity nanowire is higher than the geometry percolation threshold, although existing correlations in percolation theory do not fit the results due to the phonon interface scattering. On the other hand, when the the size of nanowires is small and the volumetric fraction of high thermal conductivity nanowire is less than percolation threshold, the thermal conductivity of the nanocomposites decreases with increasing the volumetric fraction of the high thermal conductivity nanowires. The results of this study may help the development of nanoscale thermoelectric materials in which the figure of merit is optimized by choosing appropriate nanowire size, property contrast and composition. RY acknowledges the funding support for this work by DoD/AFOSR MURI grant FA9550-06-1-0326. The simulation was conducted on a 24-node cluster supported by Intel Corporation and managed by Prof. Gang Chen and Mr. Lu Hu at MIT.

  5. The small volume particle microsampler (SVPM): a new approach to particle size distribution and composition

    Microsoft Academic Search

    Marie-Claude Archambault; Jon Grant; Annamarie Hatcher

    2001-01-01

    The characterization of trophically and geochemically important suspended particulate matter (SPM) has traditionally relied on bottle sampling and subsequent analysis with Coulter Multisizers and other instruments, which are not sufficient in preserving the in situ size, shape and composition of aggregated particles. The small volume particle microsampler (SVPM) is a sampling device that captures individual particles on filters with minimal

  6. The effect of spatial distribution on the effective behavior of composite materials and cracked media

    Microsoft Academic Search

    P. Ponte Castañeda; J. R. Willis

    1995-01-01

    Estimates of the Hashin-Shtrikman type are developed for the overall moduli of composites consisting of a matrix containing one or more populations of inclusions, when the spatial correlations of inclusion locations take particular “ellipsoidal” forms. Inclusion shapes can be selected independently of the shapes adopted for the spatial correlations. The formulae that result are completely explicit and easy to use.

  7. Sources, distribution and composition of the suspended sediments, Kuwait Bay, Northern Arabian Gulf

    Microsoft Academic Search

    A. N. Al-Ghadban; A. El-Sammak

    2005-01-01

    Qualitative and quantitative assessment of suspended sediment levels and transport pathways in Kuwait's northern territorial waters are described, with special reference to Kuwait Bay. Near-surface water samples were collected from 12 stations, covering the whole of the embayment. Suspended sediment concentrations (SSCs) were derived. Heavy metal concentrations, mineralogical composition and grain size constituents were derived for the suspended sediments retained

  8. Glass ceramic composite materials with uniform continuous reinforcing fiber distribution and a unit for their production

    Microsoft Academic Search

    A. E. Rutkovskii; A. A. Chekhovskii; V. V. Furman; I. P. Aleksenko

    1993-01-01

    The production conditions and structure for composite materials based on glass ceramic reinforced with electrically conducting fibers have been examined. A unit is described for applying coatings on continuously moving fiber using electrophoresis. It is shown that it is practical to vary the volume relationship between the matrix and the fiber over wide ranges.

  9. Damage Detection for Composite Laminate Plates with A Distributed Hybrid PZT\\/FBG Sensor Network

    Microsoft Academic Search

    Zhanjun Wu; Xinlin P. Qing; Fu-Kuo Chang

    2009-01-01

    Debond detection is a critical technique to ensure composite structural safety. Although there are many novel sensors being developed in recent years, piezoelectric transducers (PZT) and fiber Bragg grating (FBG) sensors have been shown as ideal sensors for monitoring structural health. To utilize their merits and overcome their drawbacks a hybrid PZT\\/FBG system has been developed to detect damage in

  10. Effect of densification mechanism on the S2 grain boundary plane distribution in WCCo composites

    E-print Network

    Rohrer, Gregory S.

    Keywords: Grain boundary Cemented carbide Sintering Electron microscopy Five parameter analysis a b s t r in the measured mechanical properties of the WC­Co composites. 2. Experimental The two cemented carbide samples are important engineering materials widely used for their hardness and abrasion resistance. Among carbide/carbide

  11. Search for quark compositeness in dijet angular distributions from pp collisions at sqrt(s) = 7 TeV

    SciTech Connect

    Chatrchyan, Serguei [Yerevan Physics Inst. (Armenia); et al.

    2012-05-01

    A search for quark compositeness using dijet angular distributions from pp collisions at sqrt(s) = 7 TeV is presented. The search has been carried out using a data sample corresponding to an integrated luminosity of 2.2 inverse femtobarns, recorded by the CMS experiment at the LHC. Normalized dijet angular distributions have been measured for dijet invariant masses from 0.4 TeV to above 3 TeV and compared with a variety of contact interaction models, including those which take into account the effects of next-to-leading-order QCD corrections. The data are found to be in agreement with the predictions of perturbative QCD, and lower limits are obtained on the contact interaction scale, ranging from 7.5 up to 14.5 TeV at 95% confidence level.

  12. Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures.

    PubMed

    Yokoyama, Daiichiro; Shinya, Akikazu; Gomi, Harunori; Vallittu, Pekka K; Shinya, Akiyoshi

    2012-01-01

    Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine. FRC framework was made of isotropic, continuous, unidirectional E-glass fibers. Maximum principal stresses were calculated using finite element method (FEM). Test results revealed that differences in the mechanical properties of adhesive resin cements led to different stress distributions at the cement interfaces between AFPD and abutment teeth. Clinical implication of these findings suggested that the safety and longevity of an AFPD depended on choosing an adhesive resin cement with the appropriate mechanical properties. PMID:22447051

  13. A feasibility study of altered spatial distribution of losses induced by eddy currents in body composition analysis

    PubMed Central

    2010-01-01

    Background Tomographic imaging has revealed that the body mass index does not give a reliable state of overall fitness. However, high measurement costs make the tomographic imaging unsuitable for large scale studies or repeated individual use. This paper reports an experimental investigation of a new electromagnetic method and its feasibility for assessing body composition. The method is called body electrical loss analysis (BELA). Methods The BELA method uses a high-Q parallel resonant circuit to produce a time-varying magnetic field. The Q of the resonator changes when the sample is placed in its coil. This is caused by induced eddy currents in the sample. The new idea in the BELA method is the altered spatial distribution of the electrical losses generated by these currents. The distribution of losses is varied using different excitation frequencies. The feasibility of the method was tested using simplified phantoms. Two of these phantoms were rough estimations of human torso. One had fat in the middle of its volume and saline solution in the outer shell volume. The other had reversed conductivity distributions. The phantoms were placed in the resonator and the change in the losses was measured. Five different excitation frequencies from 100 kHz to 200 kHz were used. Results The rate of loss as a function of frequency was observed to be approximately three times larger for a phantom with fat in the middle of its volume than for one with fat in its outer shell volume. Conclusions At higher frequencies the major signal contribution can be shifted toward outer shell volume. This enables probing the conductivity distribution of the subject by weighting outer structural components. The authors expect that the loss changing rate over frequency can be a potential index for body composition analysis. PMID:21047441

  14. The Stability of Rankings Derived from Composite Indicators: Analysis of the "IL Sole 24 Ore" Quality of Life Report

    ERIC Educational Resources Information Center

    Lun, G.; Holzer, D.; Tappeiner, G.; Tappeiner, U.

    2006-01-01

    The calculation of composite indicators and the derivation of respective rankings is a common method used to benchmark countries or regions. However, although the statistical robustness of these rankings is often criticised, they often still spark off heated political debate. Here, we assess the sensitivity of the province ranking published by the…

  15. Fatigue properties of jointed wood composites Part I Statistical analysis, fatigue master curves and constant life diagrams

    Microsoft Academic Search

    I. P. Bond; M. P. Ansell

    1998-01-01

    The primary aim of this work was to assess the fatigue performance of scarf-jointed laminated wood composites used to manufacture wind turbine blades and establish simple fatigue design procedures. Laminates made from poplar (Populus canadensis\\/serotina), Khaya (Khaya ivorensis) and beech (Fagus sylvatica), incorporating typical scarf joints, were assessed under reversed loading (R =-1). Scarf joints were found to be great

  16. Extending the shelf-life and proximate composition stability of ready to eat foods in vacuum or modified atmosphere packaging

    Microsoft Academic Search

    M. Antonia Murcia; Magdalena Mart??nez-Tomé; M. Carmen Nicolás; Ana M Vera

    2003-01-01

    The stability of the proximate composition (moisture, proteins, lipids and ash) and the microbiological state of cooked ‘ready to eat’ foods in vacuum or modified atmosphere packaging were examined and compared with conventionally packaged (in air) foods. The study was carried out for 7 and 29 days, during which time the food products were stored at 3°C. Vacuum or modified

  17. Distribution and enantiomeric composition of amino acids in the Murchison meteorite

    NASA Technical Reports Server (NTRS)

    Engel, M. H.; Nagy, B.

    1982-01-01

    Studies of the amino acid contents and enantiomeric compositions of a single stone from the Murchison meteorite are reported. Water-extracted and 6M HCl-extracted samples from the meteorite interior of meteorite fragments were analyzed by gas chromatography and combined gas chromatography-chemical ionization mass spectrometry. Examination of the D/L ratios of glutamic acid, aspartic acid, proline, leucine and alanine reveals those amino acids extractable by water to be partially racemized, whereas the acid-extracted amino acids were less racemized. The amino acid composition of the stone is similar to those previously reported, including the absence of serine, threonine, tyrosine phenylalanine and methionine and the presence of unusual amino acids including such as isovaline, alpha-aminoisobutyric acid and pseudoleucine. It is concluded that the most likely mechanism accounting for the occurrence of nonracemic amino acid mixtures in the Murchison meteorite is by extraterrestrial stereoselective synthesis or decomposition reactions.

  18. Measurement of internal die pressure distributions during pultrusion of thermoplastic composites

    NASA Astrophysics Data System (ADS)

    Fanucci, Jerome P.; Nolet, Stephen C.; Koppernaes, Christian; Kim, Young R.

    This paper describes the development and use of a thin, disposable pressure sensor designed specifically for monitoring pointwise through-the-thickness consolidation forces developed during composite processing. The unique postage stamp-sized sensor (11.1 mm diameter active gage area and 0.31 mm thickness) can be placed directly at points in or on a laminate where pressure data is desired. The sonsor's small dimensions and low cost permit it to be treated as a disposable item in aerospace and other composite fabrication applications. This paper will illustrate the use of the sensor as a means of measuring the pressures developed inside a die during the pultrusion of a graphite/ULTEM thermoplastic structure, as well as with other pultrusion processing examples.

  19. The distribution and composition of deep-sea microbenthos in a bathyal region of the western Coral Sea

    NASA Astrophysics Data System (ADS)

    Alongi, Daniel M.

    1987-07-01

    The distribution and composition of bathyal (298-1610 m) microbenthos were examined on the Queensland continental slope, the Coral Sea Plateau and the adjacent Queensland and Townsville troughs in the western Coral Sea. Two conspicuous changes in community composition were recorded: (1) ciliates were undetected below 700 m and (2) yeasts and yeast-like cells were undetected above 1150 m. Densities of flagellates decreased, whereas amoebae densities increased significantly with water depth. Densities of living Foraminifera ( overlinex = 56 cm-2) increased significantly from the continental slope to the adjacent troughs. Bacterial numbers ranged from 0.1 to 71.0 × 10 8 cells g -1 dry wt of sediment and decreased significantly with water depth. Chlorophyll a (0.0-19.0 ?g g -1 dry wt) and phaeopigment (0.0-4.9 ?g g -1 dry wt) concentrations suggest that phytodetritus is a major source of organic matter in this tropical region. Concentrations of organic carbon (0.22-0.52%) and nitrogen (<0.01-0.02%) were low compared to most other deep-sea sediments, with a shallow sediment depth distribution indicating little burial of organic matter. These findings, coupled with the presence of abundant protozoan populations (˜10 6 m -2), suggest the potential for rapid microbial activity and dentrital utilization in bathyal surface sediments of the western Coral Sea.

  20. The distribution and composition of vascular plant communities on Heard Island

    Microsoft Academic Search

    Jocelyne M. R. Hughes

    1987-01-01

    Six major higher plant communities are defined for sub-Antarctic Heard Island: tussock grassland, meadow, herbfield, pool complex, cushion-carpet, fellfield. The communities were mapped at a scale of 1:50000, using colour aerial photographs and field observations. The floristic composition of twelve vegetation transects and of thirty sample quadrats along these is used to describe the communities and identify dominant or indicator

  1. Characterization of Self-Healing Fiber-Reinforced Polymer-Matrix Composite with Distributed Damage

    Microsoft Academic Search

    Ever J. Barbero; Kevin J. Ford

    Th.e objective ofthis manuscript is to describe experimental work that quantifies the damage and self-healing behav­ ior of fiber-reinforced, polymer-matrix, laminated composites. The effects of damage and healing on stiffness and strength are described. While previous research looks at healing of macro-cracks, this work studies the healing of micro-cracks. Therefore, this work quantifies the effect of damage and self-healing within

  2. Composition, distribution and supposed origin of mineral inclusions in sessile oak wood — consequences for microdensitometrical analysis

    Microsoft Academic Search

    Dries Vansteenkiste; Joris Van Acker; Marc Stevens; Didier Le Thiec; Gérard Nepveu

    2007-01-01

    SEM and light-microscopical observations, supported by chemical microanalysis with an EDXA system, revealed that light-saturated\\u000a pixels observed in X-ray negatives of sessile oak (Quercus petraea Liebl.) wood were caused by inorganic deposits present inside multiseriate ray and axial parenchyma cells. Calcium oxalate\\u000a crystals, silica grains and amorphous granules with varied mineral compositions have been identified. The wood strips of three

  3. The In Situ Ply Shear Strength Distributions in Graphite\\/Epoxy Laminated Composites

    Microsoft Academic Search

    Fu-Kuo Chang; Ming-Huei Chen

    1987-01-01

    An experimental and analytical investigation was performed to study the in situ ply shear strength in fiber-reinforced laminated composites. The effects of ply orientation and laminate thickness on the ply shear strength in laminates were the major concerns of the study. T300\\/1034-C Graphite\\/Epoxy cross-ply laminates were selected for the tests, and a rail shear fixture was used for measuring ply

  4. Composite bridge behavior and load distribution influenced by shakedown and diaphragms 

    E-print Network

    Gilstrap, Christopher Max

    1991-01-01

    50 51 54 57 58 61 Figure 20. Figure 21. Differential moment modification for 2-span continuous structure Permanent deflections for composite structure before Overload tests 64 66 Figure 22. Location for concentrated load at LC-1 . Figure... 23. Location for concentrated load at LC-4 . Figure 24. Location for concentrated load at LC-2 Figure 25. Location for concentrated load at LC-5 70 70 71 71 Figure 26. Typical DL variations applied to FE model in opposite direction. Figure 27...

  5. The mineral composition and spatial distribution of the dust ejecta of NGC 6302

    E-print Network

    F. Kemper; F. J. Molster; C. Jaeger; L. B. F. M. Waters

    2002-08-06

    We have analysed the full ISO spectrum of the planetary nebula NGC 6302 in order to derive the mineralogical composition of the dust in the nebula. We use an optically thin dust model in combination with laboratory measurements of cosmic dust analogues. We find two main temperature components at about 100 and 50 K respectively, with distinctly different dust compositions. The warm component contains an important contribution from dust without strong infrared resonances. In particular the presence of small warm amorphous silicate grains can be excluded. The detection of weak PAH bands also points to a peculiar chemical composition of the dust in this oxygen-rich nebula. The cool dust component contains the bulk of the mass and shows strong emission from crystalline silicates, which contain about 10 percent of the mass. In addition, we identify the 92 micron band with the mineral calcite, and argue that the 60 micron band contains a contribution from the carbonate dolomite. We present the mass absorption coefficients of six different carbonate minerals. The geometry of the dust shell around NGC 6302 is studied with mid-infrared images obtained with TIMMI2. We argue that the cool dust component is present in a circumstellar dust torus, while the diffuse emission from the warm component originates from the lobes.

  6. The mineral composition and spatial distribution of the dust ejecta of NGC 6302

    E-print Network

    Kemper, F; Jäger, C; Waters, L B F M

    2002-01-01

    We have analysed the full ISO spectrum of the planetary nebula NGC 6302 in order to derive the mineralogical composition of the dust in the nebula. We use an optically thin dust model in combination with laboratory measurements of cosmic dust analogues. We find two main temperature components at about 100 and 50 K respectively, with distinctly different dust compositions. The warm component contains an important contribution from dust without strong infrared resonances. In particular the presence of small warm amorphous silicate grains can be excluded. The detection of weak PAH bands also points to a peculiar chemical composition of the dust in this oxygen-rich nebula. The cool dust component contains the bulk of the mass and shows strong emission from crystalline silicates, which contain about 10 percent of the mass. In addition, we identify the 92 micron band with the mineral calcite, and argue that the 60 micron band contains a contribution from the carbonate dolomite. We present the mass absorption coeffi...

  7. Alkane distribution and carbon isotope composition in fossil leaves: An interpretation of plant physiology in the geologic past

    NASA Astrophysics Data System (ADS)

    Graham, H. V.; Freeman, K. H.

    2014-12-01

    The relative chain-length distribution and carbon-isotope composition of n-alkanes extracted from sedimentary rocks are important geochemical tools for investigating past terrestrial ecosystems. Alkanes preserved in ancient sediments are assumed to be contemporaneous, derived from the same ecosystem, and integrated from the biomass present on the landscape at the time of deposition. Further, there is an underlying assumption that ancient plants exhibited the same metabolic and physiological responses to climate conditions that are observed for modern plants. Interpretations of alkane abundances and isotopic signatures are complicated by the strong influence of phylogenetic affiliation and ecological factors, such as canopy structure. A better understanding of how ecosystem and taxa influence alkane properties, including homologue abundance patterns and leaf-lipid carbon isotope fractionation would help strengthen paleoecological interpretations based on these widely employed plant biomarkers. In this study, we analyze the alkane chain-length distribution and carbon-isotope composition of phytoleim and alkanes (d13Cleaf and d13Clipid) extracted from a selection of Cretaceous and Paleocene fossil leaves from the Guaduas and Cerrejon Formations of Colombia. These data were compared with data for the same families in a modern analogue biome. Photosynthetic and biosynthetic fractionation (?leaf and elipid) values determined from the fossil material indicate carbon metabolism patterns were similar to modern plants. Fossil data were incorporated in a biomass-weighted mixing model to represent the expected lipid complement of sediment arising from this ecosystem and compared with alkane measurements from the rock matrix. Modeled and observed isotopic and abundance patterns match well for alkane homologs most abundant in plants (i.e., n-C27 to n-C33). The model illustrates the importance of understanding biases in litter flux and taphonomic pressures inherent in the fossil lipid record, and it highlights the influence of community composition and forest structure on sedimentary lipids.

  8. How Rocky Are They? The Composition Distribution of Kepler's Sub-Neptune Planet Candidates within 0.15 AU

    NASA Astrophysics Data System (ADS)

    Wolfgang, Angie; Lopez, Eric

    2015-06-01

    The Kepler Mission has found thousands of planetary candidates with radii between 1 and 4 {{R}\\oplus }. These planets have no analogues in our own solar system, providing an unprecedented opportunity to understand the range and distribution of planetary compositions allowed by planet formation and evolution. A precise mass measurement is usually required to constrain the possible composition of an individual super-Earth-sized planet, but these measurements are difficult and expensive to make for the majority of Kepler planet candidates (PCs). Fortunately, adopting a statistical approach helps us to address this question without them. In particular, we apply hierarchical Bayesian modeling to a subsample of Kepler PCs that is complete for P\\lt 25 days and {{R}pl}\\gt 1.2 {{R}\\oplus } and draw upon interior structure models that yield radii largely independent of mass by accounting for the thermal evolution of a gaseous envelope around a rocky core. Assuming the envelope is dominated by hydrogen and helium, we present the current-day composition distribution of the sub-Neptune-sized planet population and find that H+He envelopes are most likely to be ?1% of these planets’ total masses with an intrinsic scatter of ±0.5 dex. We address the gaseous/rocky transition and illustrate how our results do not result in a one-to-one relationship between mass and radius for this sub-Neptune population; accordingly, dynamical studies that wish to use Kepler data must adopt a probabilistic approach to accurately represent the range of possible masses at a given radius.

  9. Mass-spectrometric method for signs of life search via analysis of the element composition of the supposed biomass extracted from regolith of Mars

    NASA Astrophysics Data System (ADS)

    Luchnikov, Konstantin; Managadze, George; Chumikov, Alexander; Managadze, Nina; Vorobyova, Elena; Safronova, Anastasia

    A mass-spectrometric method for identifying signs of life in a sample extracted from regolith of extraterrestrial objects is presented. The structure and composition of a laboratory prototype of an onboard measurement facility addressing the assigned astrobiological task is analyzed. The instrument proposed can be used to analyze the element composition of the supposed extraterrestrial biomass and compare it to the element composition of terrestrial microorganisms. Biomass is to be identified by a number of criteria: the presence and abundance ratio of matrix biogenic elements - H, C, N, O; abundance ratios of biogenic markers like P/S, K/Ca, the presence of other biologically important elements (e.g., Cl) and microelements, such as Mg, Fe, Cu, Zn, and F. The results of measurements performed on microorganisms and soil samples confirm the applicability of this solution. Various methods of extracting the biomass from different space bodies are discussed. The element composition of the sample studied is to be performed using the onboard LASMA time-of-flight laser mass-reflectron similar to the instrument developed for the «Phobos-Grunt» mission however after significant improvement. The system of sample preparation is based on the separation of the microorganisms from regolith. After extraction of microorganisms with water the solution obtained must be desalted. Sample for investigation is produced by drying the solution on the holder being the target for laser ablation. The method can be used to search for and identify biomass in different samples including ice retrieved from the subsurface layer of Solar-System planets or satellites, e.g., Europa or Enceladus.

  10. Characterization of the zooplankton community, size composition, and distribution in relation to hydrography in the Japan/East Sea

    NASA Astrophysics Data System (ADS)

    Ashjian, Carin J.; Davis, Cabell S.; Gallager, Scott M.; Alatalo, Philip

    2005-06-01

    The Japan/East Sea (JES) may be thought of as a model or microcosm of larger oceanic systems where biogeographic boundaries juxtapose at highly dynamic boundaries. The northern and southern portions of the JES are hydrographically and biologically distinct, with the southern portion being more tropical/oligotrophic and the northern portion being more boreal/eutrophic. Regional zooplankton taxonomic and size compositions and abundance and the high-resolution vertical distribution of plankton, fluorescence, and coincident hydrography were described using the Video Plankton Recorder (VPR), equipped with high- and low-magnification cameras and environmental sensors and mounted on a vertically profiling towed vehicle, in the upper 80 m of the JES during the summer of 1999. A survey was conducted over both the northern and southern regions, including the Subpolar Front (SPF), that spanned 10-12° of latitude and longitude and covered an along track distance of 7000 km. Plankton also were collected at 15 selected stations using a ring net for silhouette analysis of taxa and size. Distributional patterns in abundance (#/liter) of plankton taxa from the VPR were quantified at sea in real time, identifying plankton automatically using a neural network classifier. The most abundant taxa identified were copepods, Oithona spp., Calanus spp., copepod nauplii, protozoa, and diatoms, with copepods the dominant taxon. The northern JES, southern JES, and North Korean Cold Current were distinct based on based on temperature-salinity properties. The hydrography was complex and characterized by multiple mesoscale features including currents and the meandering of the SPF. Different taxonomic and size compositions were observed in the three hydrographic regions. The vertical distributions of copepods and fluorescence were associated with hydrographic structure, especially at fronts. Plankton abundances varied with regional hydrographic region and environmental conditions, although strong associations were not always observed. The extremely dynamic nature of the JES may effectively mix the plankton and obscure strong gradients or differences between regions.

  11. NASA technology utilization survey on composite materials

    NASA Technical Reports Server (NTRS)

    Leeds, M. A.; Schwartz, S.; Holm, G. J.; Krainess, A. M.; Wykes, D. M.; Delzell, M. T.; Veazie, W. H., Jr.

    1972-01-01

    NASA and NASA-funded contractor contributions to the field of composite materials are surveyed. Existing and potential non-aerospace applications of the newer composite materials are emphasized. Economic factors for selection of a composite for a particular application are weight savings, performance (high strength, high elastic modulus, low coefficient of expansion, heat resistance, corrosion resistance,), longer service life, and reduced maintenance. Applications for composites in agriculture, chemical and petrochemical industries, construction, consumer goods, machinery, power generation and distribution, transportation, biomedicine, and safety are presented. With the continuing trend toward further cost reductions, composites warrant consideration in a wide range of non-aerospace applications. Composite materials discussed include filamentary reinforced materials, laminates, multiphase alloys, solid multiphase lubricants, and multiphase ceramics. New processes developed to aid in fabrication of composites are given.

  12. Composition and On Demand Deployment of Distributed Brain Activity Analysis Application on Global Grids

    Microsoft Academic Search

    R. Buyya; S. Date; Y. Mizuno-Matsumoto; S. Venugopal; D. Abramson

    The distribution of knowledge (by scientists) and data sources (advanced scientific instruments), and the need of large-scale computational resources for analyzing massive scientific data are two major problems commonly observed in scientific disciplines. The two popular scientific disciplines of this nature are brain science and high-energy physics. The analysis of brain activity data gathered from the MEG (Magnetoencephalography) instrument is

  13. Effect of Aerosol Composition on Cloud Droplet Size Distribution: A Numerical Study

    Microsoft Academic Search

    James W. Fitzgerald

    1974-01-01

    Numerical computations have been performed to study the effect on the characteristics of a condensationally produced droplet size distribution of a variability in the kind and fraction of soluble material among atmospheric aerosol particles. The model aerosol used in the study is assumed to be comprised only of nuclei containing 1, 10, 50 and 90% soluble material and to have

  14. Bacterial Composition of Biofilms Collected From Two Service Areas in a Metropolitan Drinking Water Distribution System

    EPA Science Inventory

    The development and succession of bacteria were examined by 16S rRNA gene clone libraries generated from various biofilms within a metropolitan water distribution system. Biofilms were obtained from off-line devices using polycarbonate coupons from annular reactors incubated for ...

  15. Two-point probability distribution function analysis of Co-polymer nano-composites

    E-print Network

    Garmestani, Hamid

    starting in phase i and ending in phase j Po ij Pijðr ¼ ro ijÞ ~r general vector r; ~rj j magnitude correlation functions related to microstructures of the heterogeneous material is required in the form spatial cor- relation functions can be described by a set of corresponding probability distribution

  16. ALUMINUM-CONTAINING SCALES IN WATER DISTRIBUTION SYSTEMS: PREVALENCE AND COMPOSITION

    EPA Science Inventory

    Aluminum (Al) deposits in distribution systems can have important detrimental effects on tap water quality because they can increase turbidity and interfere with disinfection, and they can increase energy loss during water transport. There is also the possibility that they have ...

  17. Noise and modulation of distributed feedback semiconductor and composite cavity lasers

    NASA Astrophysics Data System (ADS)

    Duan, Guang-Hua

    1991-08-01

    A theoretical and experimental study of noise and modulation of high performance lasers is presented. The Green's function method is generalized for complex structure lasers. In particular, two important parameters were studied: the rate of the spontaneous emission coupled to the lasing mode and the effective phase amplitude coupling factor. The enhancement of the spontaneous emission rate is calculated for different laser structures. The sensitivity of these lasers to external reflections is defined. For multielectrode lasers, it is shown that the spontaneous emission rate and the effective phase amplitude coupling factor depend simultaneously on the current injection conditions. A chirp reduction was experimentally obtained and a substantial change of the oscillation relaxation was observed for a distributed feedback laser submitted to an external optical feedback. These results are consistent with the generalized rate equations model. The locking of a distributed Bragg reflector laser to a frequency modulation sideband of another such laser was demonstrated. An extended cavity laser with 40 nm tunability and 100 kHz linewidth was realized. A heterodyne detection system was demonstrated using this tunable laser and a distributed feedback laser. The experimental results of the modulation and noise properties for a two electrode distributed Bragg reflector laser are also presented. It is shown, that the drive current noise of the Bragg section introduces an important supplementary linewidth. The influence of the nonlinear effects on the spectal linewidth of the monosection distributed feedback laser is investigated. It is shown that the material intraband gain saturation leads to an increase of the phase amplitude coupling factor. The spatial hole burning has no significant consequence in the dynamic and noise properties of semiconductor lasers.

  18. Chemical composition of essential oils of Litsea cubeba harvested from its distribution areas in China.

    PubMed

    Si, Linlin; Chen, Yicun; Han, Xiaojiao; Zhan, Zhiyong; Tian, Shengping; Cui, Qinqin; Wang, Yangdong

    2012-01-01

    Litsea cubeba (Lour.) Pers. is a promising industrial crop with fruits rich in essential oils. The chemical composition of essential oils of L. cubeba (EOLC) were determined for fruits harvested from eight regions in China. The overall essential oil content, obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS), ranged from 3.04% to 4.56%. In total, 59 compounds were identified, the dominant components being monoterpenes (94.4-98.4%), represented mainly by neral and geranial (78.7-87.4%). D-Limonene was unexpectedly a lesser constituent (0.7-5.3%) in fruits, which differed from previous reports (6.0-14.6%). Several components were only detected in certain regions and compounds such as o-cymene and eremophilene have never before been reported in EOLC. These results demonstrate significant regional variation in the chemical composition of EOLC. This investigation provides important information with regard to the bioactivity, breeding work and industrial applications of L. cubeba. PMID:22683894

  19. Analysis of the distribution of critical current of bent Bi2223 composite tape based on a unifying parameter approach

    NASA Astrophysics Data System (ADS)

    Ochiai, S.; Shin, J. K.; Okuda, H.; Sugano, M.; Hojo, M.; Osamura, K.; Kuroda, T.; Itoh, K.; Wada, H.

    2008-05-01

    A modeling study was carried out to provide a description of the critical current distribution of bent multifilamentary Bi2223/Ag/Ag alloy superconducting composite tape samples. In the modeling, the difference between the tensile fracture strain of the Bi2223 filaments along the sample length under no residual strain and residual strain was used as a unifying parameter for the description of the damage evolution. The unifying parameter was treated to be different from sample to sample and also from position to position in each sample. The statistics of the unifying parameter were combined with the shape of the core and exerted tensile strain of the Bi2223 filaments, from which the relation of the heterogeneous damage evolution to the distribution of the critical current was formulated. The proposed model was applied to the reported data of 33 samples of the round robin test of VAMAS (Versailles project on advanced materials and standard)/TWA16 (Technical working area 16, superconducting materials) in 2000-2001. The reported distributions of the critical current of the bent-damaged samples were described well by the present model.

  20. Distribution and Composition of Terrigenous Organic Matter in Surface Sediments from the Fly River Delta and Clinoform (Papua New Guinea)

    NASA Astrophysics Data System (ADS)

    Monacci, N.; Goni, M.; Gisewhite, R.; Clinton, R.; Crockett, J.; Nittrouer, C.; Ogston, A.

    2004-12-01

    The distribution of terrigenous organic matter in surface sediments from the delta and inner clinoform region off the Fly River was investigated by measuring organic carbon:nitrogen (C/N) and stable carbon (d13C) isotopic ratios, as well as the concentrations and stable isotopic compositions of lignin-derived CuO oxidation products. The average C/N and d13C ratios of the sediments from this region ranged from 11 to 70 and from -23 to -27 per mil, respectively. Lignin phenol yields ranged from 0.2 to over 9 mg/100 mg OC, with an average of 3.4 mg/100 mg OC. Most of the differences in C/N ratios and lignin yields occur within a narrow range of d13C compositions (-27 to -25 per mil), which suggest that most of the variability encountered within the surfaces sediments is due to variations in the relative abundance of vascular plant detritus (high C/N ratios and high lignin yields) and soil organic matter (lower C/N ratios and lower lignin yields). Our results suggest negligible contributions from marine organic carbon in surface sediments of the northeast region of the delta. In contrast, the most enriched d13C values and lowest lignin yields, both indicative of marine inputs, were measured in coarse sands collected in the southwest region of the Fly River delta and inner clinoform. The relative abundances of different lignin phenol classes are consistent contributions from woody and non-woody angiosperm sources. The stable carbon isotopic compositions of individual lignin phenols indicate a predominant C3 source, with no evidence for contributions from C4 vascular plant sources. Overall, these results point to C3 angiosperm vegetation from the tropical forest in the drainage basin and delta region of the Fly River as the predominant sources of terrigenous organic matter in this part of the Gulf of Papua. The spatial distribution of these two pools of organic matter will be interpreted in the context of sediment texture, mineral surface area and particle distribution processes in this region of the gulf.

  1. Vertical distribution, life cycle, and developmental characteristics of the mesopelagic calanoid copepod Gaidius variabilis (Aetideidae) in the Oyashio region, western North Pacific Ocean

    Microsoft Academic Search

    A. Yamaguchi; T. Ikeda

    2000-01-01

    Vertical distribution, life cycle, and developmental characteristics of the mesopelagic copepod Gaidius variabilis Brodsky in the Oyashio region were investigated by combining analyses of field copepodite populations with laboratory-rearing\\u000a data of egg hatching and naupliar development. Field samplings from five discrete depths between the surface and ?2000?m were\\u000a made approximately every month for 1 year. Most populations of G. variabilis

  2. Carbon, nitrogen and sulfur in lunar fines 15012 and 15013 - Abundances, distributions and isotopic compositions

    NASA Technical Reports Server (NTRS)

    Chang, S.; Lawless, J.; Romiez, M.; Kaplan, I. R.; Petrowski, C.; Sakai, H.; Smith, J. W.

    1974-01-01

    Lunar fines 15012,16 and 15013,3 were analyzed by stepwise pyrolysis and acid hydrolysis as well as complete combustion in oxygen to determine carbon, nitrogen and sulfur. In addition, hydrogen was analysed during pyrolysis as well as during hydrolysis. By comparison of the distribution frequencies of C, N, S, H2 and Fe with He-4, considered to have arisen from solar wind contribution, it is concluded that nitrogen and hydrogen have largely a solar origin. Carbon has a significant solar contribution, and metallic iron may have resulted from solar wind interaction with ferrous minerals on the lunar surface. Sulfur probably has a predominantly lunar origin. There is no direct evidence for meteorotic contribution to these samples. Solar wind interaction also has a marked effect on the stable isotope distribution of C-13/C-12, N-15/N-14, and S-34/S-32. In all cases, the heavy isotope was most enriched in the smallest grain-size fraction.

  3. Species Composition, Distribution and Management of Trees in Rice Paddy Fields in Central Lao, PDR

    Microsoft Academic Search

    Y. Kosaka; S. Takeda; S. Prixar; S. Sithirajvongsa; K. Xaydala

    2006-01-01

    Presence of different types of trees dispersed singly or in small groups throughout the fields is a very common feature in\\u000a the extensive rice paddies of Laos and Thailand. Factors such as land-settlement history, proximity to forest, and role of\\u000a species in the local culture are known to influence the nature and distribution of tree species so retained. The extent

  4. A preliminary analysis of lunar extra-mare basalts - Distribution, compositions, ages, volumes, and eruption styles

    NASA Technical Reports Server (NTRS)

    Whitford-Stark, J. L.

    1982-01-01

    Extra-mare basalts occupy 8.5% of the lunar basalt area and comprise 1% of the total mare basalt volume. They are preferentially located where the crust is thin and topographically low. In terms of age, eruption style, and composition they are as variable as the mare basalts. In some instances extrusion in extra-mare craters was preceded by floor-fracturing whereas in other cases it apparently was not. The volume of lava erupted may have been controlled more by the volume of magma produced than by hydrostatic effects. A minimum of nearly 1300 separate basalt eruptions is indicated; the true value could be nearer 30,000 separate eruptions.

  5. Diatom valve distribution and sedimentary fatty acid composition in Larsen Bay, Eastern Antarctica Peninsula

    NASA Astrophysics Data System (ADS)

    Sañé, E.; Isla, E.; Pruski, A. M.; Bárcena, M. A.; Vétion, G.; DeMaster, D.

    2011-08-01

    During austral summer 2006-2007, five sediment cores were recovered from the Eastern Antarctic Peninsula (EAP) continental shelf. Microscopic observations and sediment fatty acid (FA) composition analyses were carried out to investigate whether the drastic changes at the sea surface in EAP may be reflected in the sedimentary record. A sharp decrease in the number of diatom valves was observed below 2 cm depth. This difference between the upper 2 cm of sediment and the deeper part of the sediment column was attributed to the drastic change in the upper water column conditions after the collapse of the ice shelves, which allowed the arrival of phytoplankton debris and fresh organic matter to the sea floor in EAP. The presence of bacterial-, zooplankton- and detrital-related FA throughout EAP cores suggests that there has been an input of older and more refractory organic matter into the region, presumably by lateral transport before the Larsen ice shelves disintegration.

  6. Ecological composition and distribution of the diatoms from the Laguna Superior, Oaxaca, Mexico.

    PubMed

    Moreno-Ruiz, José Luis; Tapia-Garcia, Margarito; Licea, Sergio; Figueroa-Torres, María Guadalupe; Esquivel, Alfonso; Herrera-Galindo, Jorge Eduardo; González-Fernández, José Manuel; González-Macias, Maria Del Carmen

    2011-07-01

    A taxonomic study of diatoms was carried out in a tropical coastal lagoon. Material for this study consists of water samples obtained from February-March 1992 to November-December 2000. Qualitative and quantitative analyses showed the presence of 373 taxa of which the families Bacillariaceae (67 species) and Chaetocerotaceae (37 species) were the most abundant groups. The species Skeletonema costatum, Chaetoceros curvisetus, Coscinodiscus radiatus var. radiatus, Ditylum brightwellii, Thalassiosira eccentrica and Entomoneis alata were found associated with moderate water quality and forming blooms. In addition, a regional comparison between Mexico and South America of the identified species is given. For practical handling, indicative values obtained from their ecological composition are incorporated as well as a code of the floristic list. Achecklist of the species and their occurrence are given. PMID:22315822

  7. Composition and fatty acid distribution of bovine milk phospholipids from processed milk products

    PubMed Central

    Gallier, Sophie; Gragson, Derek; Cabral, Charles; Jiménez-Flores, Rafael; Everett, David W.

    2014-01-01

    The aim of this work was to assess the accuracy of different extraction methods of phospholipids and to measure the effect that processing has on phospholipid composition. Four methods of extracting phospholipids from buttermilk powder were compared to optimize recovery of sphingomyelin. Using the optimal method, the phospholipid profile of four dairy products (raw milk, raw cream, homogenized and pasteurized milk, and buttermilk powder) was determined. A total lipid extraction by the Folch method followed by a solid-phase extraction using the Bitman method was the most efficient technique to recover milk sphingomyelin. Milk processing (churning, centrifuging, homogenization, spray-drying) affected the profile of milk phospholipids, leading to a loss of sphingomyelin and phosphatidylcholine after centrifugation for cream separation. We also observed a corresponding decrease in the saturation content of the raw cream phospholipids, and a loss of phosphatidylethanolamine after spray-drying to produce buttermilk powder. PMID:20828196

  8. Impact of prebiotic synthesis and diagenesis on the distribution, stereochemistry, and stable isotope composition of amino acids in carbonaceous meteorites

    NASA Astrophysics Data System (ADS)

    Engel, Michael H.

    2013-09-01

    Simulation experiments for prebiotic synthesis result in racemic mixtures (D/L = 1.0) for protein and non-protein amino acids, irrespective of the composition of the precursor gas mixtures or the energy sources employed. It is therefore not surprising that it was commonly assumed that if amino acids in carbonaceous meteorites were formed by similar reactions they would also be racemic. Engel and Nagy1 and more recently Glavin et al.2 have shown that protein amino acids in carbonaceous meteorites often exhibit a moderate to strong L-amino acid excess (D/L ? 1.0). Engel3 hypothesized that this extraterrestrial L-excess might be the precursor material from which life as we know it originated. Stable isotope analysese.g 4 confirmed that the L-amino acid excess in meteorites was indigenous rather than the result of contamination subsequent to impact on Earth. A key question that arises is that since there are no known mechanisms for the direct prebiotic synthesis of amino acids with an L-enantiomer excess, how did these compounds come to exist in carbonaceous meteorites? It has been proposed5 and references therein that a series of diagenetic reactions subsequent to synthesis are responsible for the L-enantiomer excess. In this paper, this hypothesis is further explored with respect to explaining the range of D/L values for amino acids in the various types of carbonaceous meteorites as well as in different stones of the same meteorite. Possible effects of diagenesis on the stable isotope compositions of these compounds are also addressed.

  9. A geochemical modelling study of the evolution of the chemical composition of seawater linked to a global glaciation: implications for life sustainability

    NASA Astrophysics Data System (ADS)

    Le Hir, G.; Goddéris, Y.; Donnadieu, Y.; Ramstein, G.

    2007-06-01

    The Snowball Earth theory initially proposed by Kirschvink (Kirschvink, 1992) to explain the Neoproterozoic glacial episodes, suggested that the Earth was fully ice-covered at 720 My (Sturtian episode) and 640 My (Marinoan episode). This succession of extreme climatic crises induced a stress which is considered as a strong selective pressure on the evolution of life (Hoffman et al., 1998). However recent biological records (Corsetti, 2006) do not support this theory as little change is observed in the diversity of microfossils outcrops before and after the Marinoan glacial interval. In this contribution we address this apparent paradox. Using a numerical model of carbon-alkalinity global cycles, we quantify several environmental stresses caused by a global glaciation. We suggest that during global glaciations, the ocean becomes acidic (pH~6), and unsaturated with respect to carbonate minerals. Moreover the quick transition from ice-house to greenhouse conditions implies an abrupt and large shift of the oceanic surface temperature which causes an extended hypoxia. The intense continental weathering, in the aftermath of the glaciation, deeply affects the seawater composition inducing rapid changes in terms of pH and alkalinity. We also propose a new timing for post glacial perturbations and for the cap carbonates deposition, ~2 Myr instead of 200 kyr as suggested in a previous modelling study. In terms of Precambrian life sustainability, seawater pH modifications appear drastic all along the glaciation, but we show that the buffering action of the oceanic crust dissolution processes avoids a total collapse of biological productivity. In opposite short-lived and large post-glacial perturbations are more critical and may have played a role of environmental filter suggested in the classic snowball Earth theory. Only a permissive life (prokaryotes or simple eukaryotes) may explain the relative continuity in microfossils diversity observed before, during and after Neoproterozoic glaciation events.

  10. Distribution, abundance and carbon isotopic composition of gaseous hydrocarbons in Big Soda Lake, Nevada - An alkaline, meromictic lake

    NASA Technical Reports Server (NTRS)

    Oremland, R. S.; Des Marais, D. J.

    1983-01-01

    The study of the distribution and isotopic composition of low molecular weight hydrocarbon gases at the Big Soda Lake, Nevada, has shown that while neither ethylene nor propylene were found in the lake, ethane, propane, isobutane and n-butane concentrations all increased with water column depth. It is concluded that methane has a biogenic origin in both the sediments and the anoxic water column, and that C2-C4 alkanes have biogenic origins in the monimolimnion water and shallow sediments. The changes observed in delta C-13/CH4/ and CH4/(C2H6 + C3H8) with depth in the water column and sedimeents are probably due to bacterial processes, which may include anaerobic methane oxidation and different rates of methanogenesis, and C2-to-C4 alkane production by microorganisms.

  11. Characteristic features of first and second moments of fission-fragment energy distribution as functions of nucleon composition

    SciTech Connect

    Gruzintsev, E.N.; Itkis, M.G.; Mul'gin, S.I.; Okolovich, V.N.; Rusanov, A.Y.; Serdyuk, O.I.; Smirenkin, G.N.; Subbotin, M.I.

    1988-08-01

    We discuss the totality of experimental data obtained at the Alma-Ata isochronous cyclotron for the mean kinetic energy /similar to/(E/sub k/) and energy dispersion sigma/sub E//sup 2/ for nuclei with Z = 68--85, A = 165--213. The dependences of these first two moments of the E/sub k/ distribution as functions of the nucleon composition of the fissioning nucleus are found to have a new feature: a ''break'' in the curve in the vicinity of (Z/sup 2//A/sup 1//sup ///sup 3/)/sub 0/approx. =1000. This effect is due to the fact that the descent-to-scission stage is absent for fissioning nuclei with Z/sup 2//A/sup 1//sup ///sup 3/<(Z/sup 2//A/sup 1//sup ///sup 3/)/sub 0/.

  12. Mortality of the oldest old Chinese: the role of early-life nutritional status, socio-economic conditions, and sibling sex-composition.

    PubMed

    Huang, Cheng; Elo, Irma T

    2009-03-01

    Based on a nationally representative sample of 8,099 Chinese drawn from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), this study investigated the long-term health consequences of early-life nutritional status, sibling sex-composition, childhood socio-economic conditions, and place of birth on mortality at ages 80 and above between 1998 and 2005. Better nutritional status in childhood predicted lower mortality at ages 80 and above, net of childhood circumstances, adult socio-economic status, and health behaviours. In addition, sibling sex-composition had long-term health consequences, net of childhood and adult characteristics, such that women benefited from having grown up in families with only daughters, while men benefited from having grown up in families with both sons and daughters. Childhood socio-economic status was only marginally related to old-age mortality and this association was attenuated further by the inclusion of adult characteristics. Place of birth was not a significant predictor of old-age mortality. PMID:19184718

  13. Effects of different ceramic and composite materials on stress distribution in inlay and onlay cavities: 3-D finite element analysis.

    PubMed

    Yamanel, Kivanç; Caglar, Alper; Gülsahi, Kamran; Ozden, Utku Ahmet

    2009-11-01

    To reduce loss of tooth tissue and to improve esthetic results, inlay and onlay restorations are good treatment choices for extensive cavities in posterior teeth. The aim of this paper was to evaluate, by means of three-dimensional finite element analysis, the effects of restorative material and cavity design on stress distribution in the tooth structures and restorative materials. Two different nanofilled composites and two different all-ceramic materials were used in this study. A permanent molar tooth was modeled with enamel and dentin structures. 3-D inlay and onlay cavity designs were created. Von Mises, compressive, and tensile stresses on the restorative materials, core materials, enamel, and dentin were evaluated separately. On the effect of restorative material, results showed that in the case of materials with low elastic moduli, more stress was transferred to the tooth structures. Therefore, compared to the nanofilled composites, the all-ceramic inlay and onlay materials tested transferred less stress to the tooth structures. On the effect of cavity design, the onlay design was more efficacious in protecting the tooth structures than the inlay design. PMID:20019416

  14. Amino Acid Composition, Molecular Weight Distribution and Gel Electrophoresis of Walnut (Juglans regia L.) Proteins and Protein Fractionations

    PubMed Central

    Mao, Xiaoying; Hua, Yufei; Chen, Guogang

    2014-01-01

    As a by-product of oil production, walnut proteins are considered as an additional source of plant protein for human food. To make full use of the protein resource, a comprehensive understanding of composition and characteristics of walnut proteins are required. Walnut proteins have been fractionated and characterized in this study. Amino acid composition, molecular weight distribution and gel electrophoresis of walnut proteins and protein fractionations were analyzed. The proteins were sequentially separated into four fractions according to their solubility. Glutelin was the main component of the protein extract. The content of glutelin, albumin, globulin and prolamin was about 72.06%, 7.54%, 15.67% and 4.73% respectively. Glutelin, albumin and globulin have a balanced content of essential amino acids, except for methionine, with respect to the FAO pattern recommended for adults. SDS-PAGE patterns of albumin, globulin and glutelin showed several polypeptides with molecular weights 14.4 to 66.2 kDa. The pattern of walnut proteins in two-dimension electrophoresis (2-DE) showed that the isoelectric point was mainly in the range of 4.8–6.8. The results of size exclusion chromatogram indicated molecular weight of the major components of walnut proteins were between 3.54 and 81.76 kDa. PMID:24473146

  15. Composition pulling effect and strain relief mechanism in AlGaN/AlN distributed Bragg reflectors

    SciTech Connect

    Liu, B.; Zhang, R.; Ji, X. L.; Fu, D. Y.; Xie, Z. L.; Chen, D. J.; Chen, P.; Jiang, R. L.; Zheng, Y. D. [Jiangsu Provincial Key Laboratory of Advanced Photonic and Electronic Materials, School of Electronic Science and Engineering, Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing 210093 (China); Zheng, J. G. [California Institute for Telecommunications and Information Technology, University of California, Irvine, California 92697-2800 (United States)

    2011-06-27

    We report on the composition pulling effect and strain relief mechanism in AlGaN/AlN distributed Bragg reflectors (DBRs) grown on GaN template/{alpha}-Al{sub 2}O{sub 3}(0001) by metal organic chemical vapor deposition. The reciprocal space mapping contours reveal that these DBRs are coherently grown. Cross-section transmission electron microscopy image of the AlGaN/AlN DBRs and the energy-dispersive x-ray analysis indicate that an AlGaN layer with gradient Al composition is located between the Al{sub 0.4}Ga{sub 0.6}N and AlN layers along the [0001] direction. It is attributed to the fact that Ga atoms in AlGaN are pulled and segregated to the upper layer by the strain. The density of strain energy is estimated to reduce more than one order by forming this quasi-three-sublayer structure comparing to the designed bi-sublayer structure.

  16. Body size, body composition and fat distribution: comparative analysis of European, Maori, Pacific Island and Asian Indian adults.

    PubMed

    Rush, Elaine C; Freitas, Ismael; Plank, Lindsay D

    2009-08-01

    Although there is evidence that Asian Indians, Polynesians and Europeans differ in their body fat (BF)-BMI relationships, detailed comparative analysis of their underlying body composition and build characteristics is lacking. We investigated differences in the relationships between body fatness and BMI, fat distribution, muscularity, bone mineral mass, leg length and age-related changes in body composition between these ethnic groups. Cross-sectional analysis of 933 European, Maori, Pacific Island and Asian Indian adult volunteers was performed for total and percentage of BF, abdominal fat, thigh fat, appendicular muscle mass, bone mineral content and leg length measured by dual-energy X-ray absorptiometry. Asian Indian men and women (BMI of 24 and 26 kg/m2, respectively) had the same percentage of BF as Europeans with a BMI of 30 kg/m2 or Pacific men and women with BMI of 34 and 35 kg/m2, respectively. Asian Indians had more fat, both total and in the abdominal region, with less lean mass, skeletal muscle and bone mineral than all other ethnic groups. Leg length was relatively longer in Pacific men and Asian and Pacific women than in other ethnic groups. In Asian Indians, abdominal fat increased with increasing age, while the percentage of BF showed little change. In the other ethnic groups, both abdominal and total BF increased with age. In conclusion, ethnic differences in fat distribution, muscularity, bone mass and leg length may contribute to ethnic-specific relationships between body fatness and BMI. The use of universal BMI cut-off points may not be appropriate for the comparison of obesity prevalence between ethnic groups. PMID:19203416

  17. Composition, distribution, and characterization of polycyclic aromatic hydrocarbons in soil in Linfen, China

    SciTech Connect

    Fu, S.; Cheng, H.X.; Liu, Y.H.; Xia, X.J.; Xu, X.B. [Chinese Academy of Sciences, Beijing (China)

    2009-02-15

    A total of 10 surface soil samples representing the entire area of Linfen City were collected and analyzed for the presence of 16 polycyclic aromatic hydrocarbons. The total polycyclic aromatic hydrocarbon concentration ranged from 1.1 to 63.7 {mu} g g{sup -1}. Analysis of the sources of contamination revealed that polycyclic aromatic hydrocarbons in the soil were derived from combustion sources. Specifically, the primary source of polycyclic aromatic hydrocarbons was coal combustion, but the samples were also effected to varying degrees by traffic emissions. Furthermore, increased levels of contamination were observed in northeast Linfen due to the distribution of industrial plants.

  18. Toward absolute chemical composition distribution measurement of polyolefins by high-temperature liquid chromatography hyphenated with infrared absorbance and light scattering detectors.

    PubMed

    Lee, Dean; Shan, Colin Li Pi; Meunier, David M; Lyons, John W; Cong, Rongjuan; deGroot, A Willem

    2014-09-01

    Chemical composition distribution (CCD) is a fundamental metric for representing molecular structures of copolymers in addition to molecular weight distribution (MWD). Solvent gradient interaction chromatography (SGIC) is commonly used to separate copolymers by chemical composition in order to obtain CCD. The separation of polymer in SGIC is, however, not only affected by chemical composition but also by molecular weight and architecture. The ability to measure composition and MW simultaneously after separation would be beneficial for understanding the impact of different factors and deriving true CCD. In this study, comprehensive two-dimensional chromatography (2D) was coupled with infrared absorbance (IR5) and light scattering (LS) detectors for characterization of ethylene-propylene copolymers. Polymers were first separated by SGIC as the first dimension chromatography (D1). The separated fractions were then characterized by the second dimension (D2) size exclusion chromatography (SEC) with IR5 and LS detectors. The concentrations and compositions of the separated fractions were measured online using the IR5 detector. The MWs of the fractions were measured by the ratio of LS to IR5 signals. A metric was derived from online concentration and composition data to represent CCD breadth. The metric was shown to be independent of separation gradients for an "absolute" measurement of CCD breadth. By combining online composition and MW data, the relationship of MW as a function of chemical composition was obtained. This relationship was qualitatively consistent with the results by SEC coupled to IR5, which measures chemical composition as a function of logMW. The simultaneous measurements of composition and MW give the opportunity to study the SGIC separation mechanism and derive chain architectural characteristics of polymer chains. PMID:25117509

  19. Airborne brake wear debris: size distributions, composition, and a comparison of dynamometer and vehicle tests.

    PubMed

    Sanders, Paul G; Xu, Ning; Dalka, Tom M; Maricq, M Matti

    2003-09-15

    Particle size distributions of light-duty vehicle brake wear debris are reported with careful attention paid to avoid sampling biases. Electrical low-pressure impactor and micro-orifice uniform deposit impactor measurements yield consistent size distributions, and the net particulate matter mass from each method is in good agreement with gravimetric filter measurements. The mass mean diameter of wear debris from braking events representative of urban driving is 6 microm, and the number-weighted mean is 1-2 microm for three currently used classes of lining materials: low metallic, semimetallic, and non-asbestos organic (NAO). In contrast, the wear rates are very material dependent, both in number and mass of particles, with 3-4 times higher emissions observed from the low metallic linings as compared to the semimetallic and NAO linings. Wind tunnel and test track measurements demonstrate the appearance of micron size particles that correlate with braking events, with approximately 50% of the wear debris being airborne for the test vehicle in this study. Elemental analysis of the wear debris reveals a consistent presence of the elements Fe, Cu, and Ba in both dynamometer and test track samples. PMID:14524436

  20. Electrical properties of polypropylene-based composites controlled by multilayered distribution of conductive particles.

    PubMed

    Gao, Wanli; Zheng, Yu; Shen, Jiabin; Guo, Shaoyun

    2015-01-28

    Materials consisting of alternating layers of pure polypropylene (PP) and carbon black filled polypropylene (PPCB) were fabricated in this work. The electrical behaviors of the multilayered composites were investigated from two directions: (1) Parallel to interfaces. The confined layer space allowed for a more compact connection between CB particles, while the conductive pathways tended to be broken up with increasing number of layers leading to a distinct enhancement of the electrical resistivity due to the separation of insulated PP layers. (2) Vertical to interfaces. The alternating assemblies of insulated and conductive layers like a parallel-plate capacitor made the electrical conductivity become frequency dependent. Following the layer multiplication process, the dielectric permittivity was significantly enhanced due to the accumulation of electrical charges at interfaces. Thus, as a microwave was incident on the dielectric medium, the interfacial polarization made the main contribution to inherent dissipation of microwave energy, so that the absorbing peak became strengthened when the material had more layers. Furthermore, the layer interfaces in the multilayered system were also effective to inhibit the propagation of cracks in the stretching process, leading to a larger elongation at the break than that of the PP/CB conventional system, which provided a potential route to fabricate electrical materials with optimal mechanical properties. PMID:25549245

  1. Sterol composition of yeast organelle membranes and subcellular distribution of enzymes involved in sterol metabolism.

    PubMed Central

    Zinser, E; Paltauf, F; Daum, G

    1993-01-01

    Organelles of the yeast Saccharomyces cerevisiae were isolated and analyzed for sterol composition and the activity of three enzymes involved in sterol metabolism. The plasma membrane and secretory vesicles, the fractions with the highest sterol contents, contain ergosterol as the major sterol. In other subcellular membranes, which exhibit lower sterol contents, intermediates of the sterol biosynthetic pathway were found at higher percentages. Lipid particles contain, in addition to ergosterol, large amounts of zymosterol, fecosterol, and episterol. These sterols are present esterified with long-chain fatty acids in this subcellular compartment, which also harbors practically all of the triacylglycerols present in the cell but very little phospholipids and proteins. Sterol delta 24-methyltransferase, an enzyme that catalyzes one of the late steps in sterol biosynthesis, was localized almost exclusively in lipid particles. Steryl ester formation is a microsomal process, whereas steryl ester hydrolysis occurs in the plasma membrane and in secretory vesicles. The fact that synthesis, storage, and hydrolysis of steryl esters occur in different subcellular compartments gives rise to the view that ergosteryl esters of lipid particles might serve as intermediates for the supply of ergosterol from internal membranes to the plasma membrane. PMID:8491706

  2. Does smoking have any effect on urinary stone composition and the distribution of trace elements in urine and stones?

    PubMed

    S?ojewski, Marcin; Czerny, Bogus?aw; Safranow, Krzysztof; Dro?dzik, Marek; Pawlik, Andrzej; Jakubowska, Katarzyna; Olszewska, Maria; Go?ab, Adam; Byra, Elzbieta; Chlubek, Dariusz; Sikorski, Andrzej

    2009-12-01

    The role of particular elements in lithogenesis is still unclear and debated. Probably some of them may promote or conversely inhibit crystal nucleation of organic or mineral species. A few epidemiological data link smoking with the risk of calcium stones. The aim of this hospital-based study was to evaluate the distribution of trace elements in urine and urinary stones, and possible correlation with stone constituents in smoking and non-smoking individuals. 209 stones and urine samples collected from idiopathic stone-formers were analyzed to evaluate the mineral composition and the distribution of elements, 29 in stones and 21 in urine. Values were statistically compared considering smoking, arterial hypertension and coronary heart disease as grouping variables. No differences were noted either for comparison of mineral components or the elements concentrations in stones in both groups. The concentration of mercury in urine was higher in smokers than in non-smokers, but the statistical significance was at the moderate level. Our findings do not support the concept of possible association between smoking and urinary lithogenesis, but we believe that further investigations are needed in this area. PMID:19826801

  3. A formalism for scattering of complex composite structures. II. Distributed reference points

    NASA Astrophysics Data System (ADS)

    Svaneborg, Carsten; Pedersen, Jan Skov

    2012-04-01

    Recently, we developed a formalism for the scattering from linear and acyclic branched structures build of mutually non-interacting sub-units. [C. Svaneborg and J. S. Pedersen, J. Chem. Phys. 136, 104105 (2012)], 10.1063/1.3682778 We assumed each sub-unit has reference points associated with it. These are well-defined positions where sub-units can be linked together. In the present paper, we generalize the formalism to the case where each reference point can represent a distribution of potential link positions. We also present a generalized diagrammatic representation of the formalism. Scattering expressions required to model rods, polymers, loops, flat circular disks, rigid spheres, and cylinders are derived, and we use them to illustrate the formalism by deriving the generic scattering expression for micelles and bottle-brush structures and show how the scattering is affected by different choices of potential link positions and sub-unit choices.

  4. Abundance, distribution, and isotopic composition of particulate black carbon in the northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Yang, Weifeng; Guo, Laodong

    2014-11-01

    There exists increasing evidence supporting the important role of black carbon in global carbon cycles. Particulate black carbon (PBC) is allochthonous and has distinct reactivities compared to the bulk particulate organic carbon (tot-POC) in marine environments. However, the abundance, geochemical behavior of PBC and its importance in oceanic carbon budget remain poorly understood. Here we report the abundance, distribution, and stable isotopic signatures of BC derived from the chemo-thermal oxidation (CTO-375) method (BCCTO) in the Gulf of Mexico. Our results show that BCCTO abundance decreased from shelf to basin, and more than a half of riverine BCCTO could be removed over the shelf. Moreover, BCCTO is much more refractory compared to the tot-POC and has ?13C values lower than those of BC-excluded POC. These results highlight the significance of PBC in marine carbon cycles and potentially suggest the need for a new end-member term in quantifying POC sources in the ocean.

  5. Distribution and Compositional Constraints on Subsurface Ice in Arcadia Planitia, Mars

    NASA Astrophysics Data System (ADS)

    Bramson, Ali M.; Byrne, Shane; Putzig, Nathaniel E.; Mattson, Sarah; Plaut, Jeffrey J.; Holt, John W.

    2014-11-01

    Knowledge of the present-day quantity and distribution of water ice on Mars can help to understand past Martian climates, and also has implications for future human exploration. Within the northern mid-latitudes, there are many geomorphological features such as ice-exposing impacts (Dundas et al., 2014) and expanded secondary craters (Viola et al., 2014) that are indicative of widespread ice.Impact crater morphology can reveal subsurface structure, such as when terraces form in layered target material (Ormö et al., 2013). We create Digital Terrain Models (DTMs) using the Mars Reconnaissance Orbiter’s HiRISE (High Resolution Imaging Science Experiment) stereo image pairs to measure terrace depths within craters (and thus the depths to the boundary of the subsurface layer). Radar sounding from the SHARAD instrument, also on the Mars Reconnaissance Orbiter, provides an independent mechanism for probing the subsurface and shows an extensive subsurface reflector in Arcadia Planitia (180-225E, 38-50N). Assuming the change in material strengths responsible for the terraces is the same dielectric interface that causes the radar reflectors, combining the terrace depths with radar delay times allows us to determine the radar wave velocity (and thus dielectric constant) of the layer of material between the surface and subsurface reflector.We present results from combining these observational datasets to map the distribution and constrain the dielectric constant of this widespread layer. Preliminary results suggest this decameters-thick layer is relatively pure excess (higher water ice abundances than can fit into the pore spaces of the regolith) ice. We compare our dielectric constant calculations with a 3-component dielectric mixing model to put limits on the porosity and purity of the ice. Understanding the conditions that emplaced and preserved this ice layer is important to improving our understanding of the Martian climate system.

  6. Diversity, composition, and geographical distribution of microbial communities in California salt marsh sediments

    USGS Publications Warehouse

    Cordova-Kreylos, A. L.; Cao, Y.; Green, P.G.; Hwang, H.-M.; Kuivila, K.M.; LaMontagne, M.G.; Van De Werfhorst, L. C.; Holden, P.A.; Scow, K.M.

    2006-01-01

    The Pacific Estuarine Ecosystem Indicators Research Consortium seeks to develop bioindicators of toxicant-induced stress and bioavailability for wetland biota. Within this framework, the effects of environmental and pollutant variables on microbial communities were studied at different spatial scales over a 2-year period. Six salt marshes along the California coastline were characterized using phospholipid fatty acid (PLFA) analysis and terminal restriction fragment length polymorphism (TRFLP) analysis. Additionally, 27 metals, six currently used pesticides, total polychlorinated biphenyls and polycyclic aromatic hydrocarbons, chlordanes, nonachlors, dichlorodiphenyldichloroethane, and dichlorodiphenyldichloroethylene were analyzed. Sampling was performed over large (between salt marshes), medium (stations within a marsh), and small (different channel depths) spatial scales. Regression and ordination analysis suggested that the spatial variation in microbial communities exceeded the variation attributable to pollutants. PLFA analysis and TRFLP canonical correspondence analysis (CCA) explained 74 and 43% of the variation, respectively, and both methods attributed 34% of the variation to tidal cycles, marsh, year, and latitude. After accounting for spatial variation using partial CCA, we found that metals had a greater effect on microbial community composition than organic pollutants had. Organic carbon and nitrogen contents were positively correlated with PLFA biomass, whereas total metal concentrations were positively correlated with biomass and diversity. Higher concentrations of heavy metals were negatively correlated with branched PLFAs and positively correlated with methyl- and cyclo-substituted PLFAs. The strong relationships observed between pollutant concentrations and some of the microbial indicators indicated the potential for using microbial community analyses in assessments of the ecosystem health of salt marshes. Copyright ?? 2006, American Society for Microbiology. All Rights Reserved.

  7. [Description, distribution, anatomy, chemical composition and uses of Mimosa tenuiflora(Fabaceae-Mimosoideae) in Mexico].

    PubMed

    Camargo-Ricalde, S L

    2000-12-01

    Because of some catastrophic events which occurred in Mexico during the 1980 decade, the utilization of "tepescohuite" bark against skin wounds and burns was popularized. The media manipulated the lack of available information about its medical properties and gave erroneous information to the society propagating a lot of myths. Therefore, the aim of this paper is to determine its taxonomic identity and to study the distribution, bark and wood anatomy of this species, and to determine its actual and historic uses, and the compilation of the information about bark pharmacology and toxicity. Its taxonomic identity is established as Mimosa tenuiflora (Willd.) Poir. (Fabaceae-Mimosoideae). It blooms and fructifies from November to June, occurring in Mexico (the states of Oaxaca and Chiapas), Guatemala, Honduras, El Salvador, Nicaragua, Panama, Colombia, Venezuela and Brazil, at altitudes of 0-1110 (-1520) m. In Mexico, it is found in dry forests, thorny thickets, Pinus and Pinus-Quercus forests, and in M. tenuiflora pure thickets, along roads and in resting or abandoned culture lands. This species has an aggregate distribution in the forests and a uniform one in the thickets. It presents a mean density of 9 individuals per m2, with 0.45 of frequency per quadrat and 1.69 m2 of mean coverture, and it has a wide range of tolerance to climatic and edaphic factors, confirming their invasive character. Regionally, the wood is used as fuel and fence construction, and against skin wounds and burns (bark tea, powder and/or ointment), and diverse products, such as shampoos, creams, capsules, soaps, etc., are commercialized. The bark is wrinkled, reddish-brown to grey, fibrous texture, 0.5-1.5 mm thick, resinous and with an astringent odor and flavor, and with a great quantity of tannins. The wood presents extremely short vessel elements, with alternate areolate punctuations, and simple perforated plates, vasicentric axial parenchima, confluent stripes, uniseriated rays, extremely short, fine and very short libriform fibres. The bark contains tannins, saponins, an alkaloide fraction, lipids, phytosterols, glucosides, xylose, rhamnose, arabinose, lupeol, methoxychalcones, and kukulkanins. PMID:11487939

  8. Effect of a Nonplanar Melt-Solid Interface on Lateral Compositional Distribution during Unidirectional Solidification of a Binary Alloy with a Constant Growth Velocity V. Part 1; Theory

    NASA Technical Reports Server (NTRS)

    Wang, Jai-Ching; Watring, Dale A.; Lehoczky, Sandor L.; Su, Ching-Hua; Gillies, Don; Szofran, Frank

    1999-01-01

    Infrared detector materials, such as Hg(1-x)Cd(x)Te, Hg(1-x)Zn(x)Te have energy gaps almost linearly proportional to its composition. Due to the wide separation of liquidus and solidus curves of their phase diagram, there are compositional segregations in both of axial and radial directions of these crystals grown in the Bridgman system unidirectionally with constant growth rate. It is important to understand the mechanisms which affect lateral segregation such that large uniform radial composition crystal is possible. Following Coriell, etc's treatment, we have developed a theory to study the effect of a curved melt-solid interface shape on the lateral composition distribution. The system is considered to be cylindrical system with azimuthal symmetric with a curved melt-solid interface shape which can be expressed as a linear combination of a series of Bessell's functions. The results show that melt-solid interface shape has a dominate effect on lateral composition distribution of these systems. For small values of b, the solute concentration at the melt-solid interface scales linearly with interface shape with a proportional constant of the product of b and (1 - k), where b = VR/D, with V as growth velocity, R as sample radius, D as diffusion constant and k as distribution constant. A detailed theory will be presented. A computer code has been developed and simulations have been performed and compared with experimental results. These will be published in another paper.

  9. Effect of a Nonplanar Melt-Solid Interface On Lateral Compositional Distribution During Unidirectional Solidification of a Binary Alloy with a Constant Growth Velocity V. Pt. 1; Theory

    NASA Technical Reports Server (NTRS)

    Wang, Jai-Ching; Watring, D.; Lehoczky. S. L.; Su, C. H.; Gillies, D.; Szofran, F.; Sha, Y. G.; Sha, Y. G.

    1999-01-01

    Infrared detected materials, such as Hg(1-x)Cd(x)Te, Hg(1-x)Zn(x)Te have energy gaps almost linearly proportional to their composition. Due to the wide separation of liquidus and solidus curves of their phase diagram, there are compositional segregation in both of the axial and radial directions of these crystals grown in the Bridgman system unidirectionally with constant growth rate. It is important to understand the mechanisms, which affect lateral segregation such that large radially uniform composition crystal can be produced. Following Coriel, etc's treatment, we have developed a theory to study the effect of a curved melt-solid interface shape on lateral composition distribution. The model is considered to be a cylindrical system with azimuthal symmetry and a curved melt-solid interface shape which can be expressed as a linear combination of a series of Bessell's functions. The results show that melt-solid interface shape has a dominant effect on the lateral composition distribution of these systems. For small values of beta, the solute concentration at the melt-solid interface scales linearly with interface shape with a proportional constant of the produce of beta and (1 -k), where beta = VR/D, with V as growth velocity, R as the sample radius, D as the diffusion constant and k as the distribution constant. A detailed theory will be presented. A computer code has been developed and simulations have been performed and compared with experimental results. These will be published in another paper.

  10. Macrobenthos composition, distribution and abundance within Sungai Pulai estuary, Johor, Malaysia

    NASA Astrophysics Data System (ADS)

    Shi, Guan Wan; Min, Lee Di; Ghaffar, Mazlan Abd; Ali, Masni Md; Cob, Zaidi Che

    2014-09-01

    Macrobenthos are very useful organisms for monitoring marine environmental and widely use in marine ecology research. They are able to monitor the difference phase in the recovery stage of disturbed sites by appear different species macrobenthos after the cessation of the impact. Univariate and multivariate methods were use to study the macrobenthos community within Sungai Pulai estuary, Johor, Malaysia. Five sub-samples were taken at each sampling sites by using 10 cm diameter corer. Crustaceans were the most abundant at Tanjung Adang (St. 1) and the station of non-seagrass area (St. 2) while polychaetes were the most abundant at Merambong Shoal (St. 3). Higher density of macrobenthos was found at St.3 followed by St. 1 and St. 2. The commonly used population indices such as diversity, richness, evenness and dominance were employed to determine the differences in diversity and abundance of macrobenthos. The diversity, richness and evenness index values showed slight increment from Station 1 to Station 3, while the dominance index decreasing trend from Station 1 to Station 3. A total 21 polychaete families were collected in Sungai Pulai estuary, which was dominated by the Spionidae, Capitellidae and Glyceridae. Cluster (Bray-Curtis similarities) analyses revealed that the Tanjung Adang and Merambong Shoal population were clearly separated from the station non-seagrass. For the time being factors that influence the pattern of distribution of the macrobenthos cannot be determined and subjected to further studies.

  11. Lipid composition and vertical distribution of bacteria in aerobic sediments of the Venezuela Basin

    NASA Astrophysics Data System (ADS)

    Harvey, H. Rodger; Richardson, Michael D.; Patton, John S.

    1984-04-01

    Box cores of surface (0 to 30-cm) sediments from carbonate, hemipelagic, and turbidite sediment types of the deep (3493 to 5039-m) Venezuelan Basin were analyzed to investigate the relationship between the vertical distribution of bacteria, lipids, lipid phosphate, and grain size. The polar lipid fraction was isolated chromatographically and quantified by flame-ionization detection using the Iatroscan TH-10 analyzer. Total bacterial abundance was measured by epifluorescence microscopy in sediments (0 to 20-cm) from the carbonate and turbidite sediments. In all three sediment types investigated, both total and polar lipid concentrations decreased with increasing depth in the sediment. The highest total and polar lipid concentrations were at the sediment-water interface (0 to 2-cm) of hemipelagic sediments (62.0 and 25.7 ?g g -1 dry sediment, respectively) followed by the carbonate and turbidite sediments. A similar decline in lipid phosphate was also observed. Bacterial abundance was > 5 × 10 8 bacteria (per gram dry sediment) at the sediment surface in both sediments examined and over 1 × 10 7 bacteria 20 cm below the sediment-water interface. Polar lipid and lipid phosphate concentrations did not appear to correlate with estimates of bacterial biomass, even in regions where bacteria were apparently the only organisms present.

  12. Species composition, relative abundance and distribution of bird fauna of riverine and wetland habitats of Infranz and Yiganda at southern tip of Lake Tana, Ethiopia

    Microsoft Academic Search

    SHIMELIS AYNALEM; AFEWORK BEKELE

    This study was carried out in the southern tip of Lake Tana, Bahir Dar, covering both wet and dry seasons, from August 2006 to March 2007, with the objective to evaluate species composition, relative abundance and distribution of the bird fauna of wetlands and riverine habitat at Infranz, Lake Tana, Ethiopia. Sampling sites were stratified based on the vegetation type

  13. COMPOSITION, DENSITY AND DISTRIBUTION OF ZOOPLANKTON IN SOUTH WEST AND EAST LAKES OF BEIRA LAKE SOON AFTER THE RESTORATION OF SOUTH WEST LAKE

    Microsoft Academic Search

    A. I. Kamaladasa; Y. N. A. Jayatunga

    A study was carried out in restored South West Lake and non-restored East Lake, of Beira lake with the objective of determining the species composition, density and distribution of zooplankton. Water was sampled from the surface and at a depth of 1 m, from February to March, 2005 between 0900-1130 h. Three rotifers species; Brachinonus calyciflorus, Keratella tropica, Filinia sp.,

  14. Paradata for 'Distribution, Habitat Use and Life History of Stream-dwelling Crayfish in the Spring River Drainage of Arkansas and Missouri with a Focus on the Imperiled Mammoth Spring Crayfish (Orconectes marchandi)'

    NSDL National Science Digital Library

    This record contains paradata for the resource 'Distribution, Habitat Use and Life History of Stream-dwelling Crayfish in the Spring River Drainage of Arkansas and Missouri with a Focus on the Imperiled Mammoth Spring Crayfish (Orconectes marchandi)'

  15. Composition, Acquisition, and Distribution of the Vi Exopolysaccharide-Encoding Salmonella enterica Pathogenicity Island SPI-7

    PubMed Central

    Pickard, Derek; Wain, John; Baker, Stephen; Line, Alexandra; Chohan, Sonia; Fookes, Maria; Barron, Andrew; Ó Gaora, Peadar; Chabalgoity, José A.; Thanky, Niren; Scholes, Christoph; Thomson, Nicholas; Quail, Michael; Parkhill, Julian; Dougan, Gordon

    2003-01-01

    Vi capsular polysaccharide production is encoded by the viaB locus, which has a limited distribution in Salmonella enterica serovars. In S. enterica serovar Typhi, viaB is encoded on a 134-kb pathogenicity island known as SPI-7 that is located between partially duplicated tRNApheU sites. Functional and bioinformatic analysis suggests that SPI-7 has a mosaic structure and may have evolved as a consequence of several independent insertion events. Analysis of viaB-associated DNA in Vi-positive S. enterica serovar Paratyphi C and S. enterica serovar Dublin isolates revealed the presence of similar SPI-7 islands. In S. enterica serovars Paratyphi C and Dublin, the SopE bacteriophage and a 15-kb fragment adjacent to the intact tRNApheU site were absent. In S. enterica serovar Paratyphi C only, a region encoding a type IV pilus involved in the adherence of S. enterica serovar Typhi to host cells was missing. The remainder of the SPI-7 islands investigated exhibited over 99% DNA sequence identity in the three serovars. Of 30 other Salmonella serovars examined, 24 contained no insertions at the equivalent tRNApheU site, 2 had a 3.7-kb insertion, and 4 showed sequence variation at the tRNApheU-phoN junction, which was not analyzed further. Sequence analysis of the SPI-7 region from S. enterica serovar Typhi strain CT18 revealed significant synteny with clusters of genes from a variety of saprophytic bacteria and phytobacteria, including Pseudomonas aeruginosa and Xanthomonas axonopodis pv. citri. This analysis suggested that SPI-7 may be a mobile element, such as a conjugative transposon or an integrated plasmid remnant. PMID:12923078

  16. Association of Coronary Wall Shear Stress With Atherosclerotic Plaque Burden, Composition, and Distribution in Patients With Coronary Artery Disease

    PubMed Central

    Eshtehardi, Parham; McDaniel, Michael C.; Suo, Jin; Dhawan, Saurabh S.; Timmins, Lucas H.; Binongo, José Nilo G.; Golub, Lucas J.; Corban, Michel T.; Finn, Aloke V.; Oshinski, John N.; Quyyumi, Arshed A.; Giddens, Don P.; Samady, Habib

    2012-01-01

    Background Extremes of wall shear stress (WSS) have been associated with plaque progression and transformation, which has raised interest in the clinical assessment of WSS. We hypothesized that calculated coronary WSS is predicted only partially by luminal geometry and that WSS is related to plaque composition. Methods and Results Twenty?seven patients with coronary artery disease underwent virtual histology intravascular ultrasound and Doppler velocity measurement for computational fluid dynamics modeling for WSS calculation in each virtual histology intravascular ultrasound segment (N=3581 segments). We assessed the association of WSS with plaque burden and distribution and with plaque composition. WSS remained relatively constant across the lower 3 quartiles of plaque burden (P=0.08) but increased in the highest quartile of plaque burden (P<0.001). Segments distal to lesions or within bifurcations were more likely to have low WSS (P<0.001). However, the majority of segments distal to lesions (80%) and within bifurcations (89%) did not exhibit low WSS. After adjustment for plaque burden, there was a negative association between WSS and percent necrotic core and calcium. For every 10 dynes/cm2 increase in WSS, percent necrotic core decreased by 17% (P=0.01), and percent dense calcium decreased by 17% (P<0.001). There was no significant association between WSS and percent of fibrous or fibrofatty plaque components (P=NS). Conclusions In patients with coronary artery disease: (1) Luminal geometry predicts calculated WSS only partially, which suggests that detailed computational techniques must be used to calculate WSS. (2) Low WSS is associated with plaque necrotic core and calcium, independent of plaque burden, which suggests a link between WSS and coronary plaque phenotype. (J Am Heart Assoc. 2012;1:e002543 doi: 10.1161/JAHA.112.002543.) PMID:23130168

  17. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    Technology utilization of fiber reinforced composite materials is discussed in the areas of physical properties, and life prediction. Programs related to the Composite Aircraft Program are described in detail.

  18. Environmental drivers of megafaunal assemblage composition and biomass distribution over mainland and insular slopes of the Balearic Basin (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Fanelli, E.; Cartes, J. E.; Papiol, V.; López-Pérez, C.

    2013-08-01

    The influence of mesoscale physical and trophic variables on deep-sea megafauna, a scale of variation often neglected in deep-sea studies, is crucial for understanding their role in the ecosystem. Drivers of megafaunal assemblage composition and biomass distribution have been investigated in two contrasting areas of the Balearic basin in the NW Mediterranean: on the mainland slope (Catalonian coasts) and on the insular slope (North of Mallorca, Balearic Islands). An experimental bottom trawl survey was carried out during summer 2010, at stations in both sub-areas located between 450 and 2200 m water depth. Environmental data were collected simultaneously: near-bottom physical parameters, and the elemental and isotopic composition of sediments. Initially, data were analysed along the whole depth gradient, and then assemblages from the two areas were compared. Analysis of the trawls showed the existence of one group associated with the upper slope (US=450-690 m), another with the middle slope (MS=1000-1300 m) and a third with the lower slope (LS=1400-2200 m). Also, significant differences in the assemblage composition were found between mainland and insular slopes at MS. Dominance by different species was evident when the two areas were compared by SIMPER analysis. The greatest fish biomass was recorded in both areas at 1000-1300 m, a zone linked to minimum temperature and maximum O2 concentration on the bottom. Near the mainland, fish assemblages were best explained (43% of total variance, DISTLM analysis) by prey availability (gelatinous zooplankton biomass). On the insular slope, trophic webs seemed less complex and were based on vertical input of surface primary production. Decapods, which reached their highest biomass values on the upper slope, were correlated with salinity and temperature in both the areas. However, while hydrographic conditions (temperature and salinity) seemed to be the most important variables over the insular slope, resource availability (gelatinous zooplankton and Calocaris macandreae) predominated and explained 59% of decapod assemblage variation over the mainland slope. Both fish and decapods were linked to net primary production recorded over the mainland 3 months before sampling, while the delay between the input of food from the surface and fish abundance was only 1 month on the insular slope. Our results suggest that trophic relationships over insular slopes probably involve a shorter food chain than over mainland slopes and one that is likely more efficient in terms of energy transfer.

  19. Design of Bivariate Accelerated Life Tests with One Main Effect and One Interaction Effect for Log-Location-Scale Distributions

    Microsoft Academic Search

    Haiyan Xu; Heliang Fei; Zhenmin Chen

    2011-01-01

    One may think that the design of bivariate accelerated life tests (ALTs) with one main effect and one interaction effect can be extended directly from the design proposed by Escobar and Meeker (1995) for bivariate ALTs with no interaction between the two variables. However, it can be shown that the “split” method, which is used in pursuing bivariate ALTs designs

  20. District energy or distributed heating/cooling? A case study in life-cycle O & M cost decision making

    SciTech Connect

    Madigan, D.W. [van Zelm Heywood & Shadford, Inc., West Hartford, CT (United States); Evans, E.A. [Boulder Energy Associates, Boulder, CO (United States)

    1996-08-01

    Cornell University is building a new home for its Johnson Graduate School of Management. Facilities planners wanted to know if they should connect the new building to the campus district energy system or install local on-site primary heating and cooling equipment. The basis for making this decision was total life-cycle cost to install, operate, and maintain the HVAC equipment. To ensure that the lowest possible life-cycle cost would prevail, numerous combinations of water-side and air-side systems were considered. Rigorous analysis was conducted on each option using computer simulation to characterize hourly heating, cooling and electrical load shapes. This information enabled quantification of utility costs and identification of peak loads for on-site equipment sizing and costing purposes. Peak heating and cooling load information allowed assessment of district energy system capacity impacts and quantification of required district system capital expenditures. After thorough engineering analysis of a broad range of options, including on-site gas-fired cooling and thermal energy storage, life-cycle economic analysis pointed to district energy as the most cost-effective source of heating and cooling for the new building. This paper presents details on the engineering analysis and the life-cycle economic analysis and articulates the benefits of conducting a comprehensive simulation-based engineering study.

  1. Revisiting spatial distribution and biochemical composition of calcium-containing crystals in human osteoarthritic articular cartilage

    PubMed Central

    2013-01-01

    Introduction Calcium-containing (CaC) crystals, including basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP), are associated with destructive forms of osteoarthritis (OA). We assessed their distribution and biochemical and morphologic features in human knee OA cartilage. Methods We prospectively included 20 patients who underwent total knee replacement (TKR) for primary OA. CaC crystal characterization and identification involved Fourier-transform infra-red spectrometry and scanning electron microscopy of 8 to 10 cartilage zones of each knee, including medial and lateral femoral condyles and tibial plateaux and the intercondyle zone. Differential expression of genes involved in the mineralization process between cartilage with and without calcification was assessed in samples from 8 different patients by RT-PCR. Immunohistochemistry and histology studies were performed in 6 different patients. Results Mean (SEM) age and body mass index of patients at the time of TKR was 74.6 (1.7) years and 28.1 (1.6) kg/m², respectively. Preoperative X-rays showed joint calcifications (chondrocalcinosis) in 4 cases only. The medial femoro-tibial compartment was the most severely affected in all cases, and mean (SEM) Kellgren-Lawrence score was 3.8 (0.1). All 20 OA cartilages showed CaC crystals. The mineral content represented 7.7% (8.1%) of the cartilage weight. All patients showed BCP crystals, which were associated with CPP crystals for 8 joints. CaC crystals were present in all knee joint compartments and in a mean of 4.6 (1.7) of the 8 studied areas. Crystal content was similar between superficial and deep layers and between medial and femoral compartments. BCP samples showed spherical structures, typical of biological apatite, and CPP samples showed rod-shaped or cubic structures. The expression of several genes involved in mineralization, including human homolog of progressive ankylosis, plasma-cell-membrane glycoprotein 1 and tissue-nonspecific alkaline phosphatase, was upregulated in OA chondrocytes isolated from CaC crystal-containing cartilages. Conclusions CaC crystal deposition is a widespread phenomenon in human OA articular cartilage involving the entire knee cartilage including macroscopically normal and less weight-bearing zones. Cartilage calcification is associated with altered expression of genes involved in the mineralisation process. PMID:24004678

  2. Distribution and composition of suspended biogenic particles in surface waters across Subarctic and Arctic Seas

    NASA Astrophysics Data System (ADS)

    Wyatt, Shea N.; Crawford, David W.; Wrohan, Ian A.; Varela, Diana E.

    2013-12-01

    Suspended biogenic particles were examined across Subarctic and Arctic Seas during the Canada-Three-Oceans (C3O) program in the summers of 2007 and 2008. Particulate organic carbon (POC) and nitrogen (PON), biogenic silica (bSiO2), and size-fractionated chlorophyll a (chl a) concentrations were measured within the euphotic zone throughout five domains: Eastern Subarctic North Pacific (ESNP), Bering and Chukchi Seas (BE-CH), Southern Beaufort Sea and Canada Basin (BS-CB), Canadian Arctic Archipelago (CAA), and Baffin Bay and Labrador Sea (BB-LS). Despite large variability along the sampling transect and vertically throughout the euphotic zone, domain averages of depth-integrated POC and PON were relatively invariant across the ESNP, BE-CH, CAA, and BB-LS, ranging from 546 to 670 mmol m-2 (POC) and 101 to 154 mmol m-2 (PON), but were much lower in BS-CB (199 and 78 mmol m-2, respectively). In contrast, depth-integrated bSiO2 averages were highest in BE-CH and CAA (>100 mmol m-2), intermediate in ESNP and BB-LS (34-48 mmol m-2), and low in BS-CB (6 mmol m-2). Similarly to the bSiO2 distribution, the biomass of the >5 ?m chl a size-fraction averaged 68-69% of total chl a in BE-CH and CAA, 56% in BB-LS, and 22-23% in ESNP and BS-CB. Ratios of bSiO2:PON averaged 1.10-1.30 in BE-CH and CAA, 0.30-0.34 in ESNP and BB-LS, and 0.08 in BS-CB. This study highlights the relative importance of siliceous phytoplankton such as diatoms in BE-CH and CAA, smaller nonsiliceous cells in BS-CB and ESNP, and a mixed assemblage of variably sized phytoplankton with a less siliceous component in BB-LS.

  3. Effects of Gas Composition in the Modified Atmosphere Packaging on the Shelf-life of Longissimus dorsi of Korean Native Black Pigs-Duroc Crossbred during Refrigerated Storage

    PubMed Central

    Muhlisin; Panjono; Kim, Dong Soo; Song, Yeong Rae; Lee, Sung-Jin; Lee, Jeong Koo; Lee, Sung Ki

    2014-01-01

    This study was conducted to observe the effects of gas composition in modified atmosphere packaging (MAP) on the shelf-life of Longissimus dorsi of Korean Native Black Pigs-Duroc Crossbred (KNP×D) during refrigerated storage. Muscle sample was obtained from the left side of carcass of seven months old of KNP×D barrow. The sample was sliced into 1 cm in thickness, placed on trays (two slices/tray) and filled with different gas composition, i.e. 0:20:80/O2:CO2:N2 (MAP1), 30:20:50/O2:CO2:N2 (MAP2) and 70:20:10/O2:CO2:N2 (MAP3). Other slices of sample were vacuum packed (VP) as a control. All packs were stored at 5±1°C. At 12 d of storage, pH value of MAP2 and MAP3 were higher (p<0.05) than that of MAP1 and pH value of MAP1 was higher (p<0.05) than that of VP. At 6 d of storage, redness (a*) value of MAP2 and MAP3 were higher (p<0.05) than that of VP and MAP1 and, at 9 and 12 d of storage, redness value of MAP3 was higher (p<0.05) than that of VP, MAP1, and MAP2. At 3, 6, 9, and 12 d of storage, the 2-thiobarbituric acid reactive substances (TBARS) value of MAP3 was higher than that of MAP2 and TBARS value of MAP2 was higher than that of VP and MAP1. At 3, 6, 9, and 12 d of storage, volatile basic nitrogen values of MAP2 and MAP3 were higher (p<0.05) than those of VP and MAP1. At 3 d of storage, total aerobic plate counts of MAP2 and MAP3 were higher (p<0.05) than those of VP and MAP1 and, at 6 d of storage, total aerobic plate counts of MAP3 was higher (p<0.05) than that of MAP1 and MAP2. However, there was no significant different total aerobic plate count among MAP1, MAP2, and MAP3 at 9 and 12 d of storage. There was no significant different total anaerobic plate count among MAP1, MAP2, and MAP3 during storage. It is concluded that the MAP containing 30:20:50/O2:CO2:N2 gas composition (MAP2) might be ideal for better meat quality for KNP×D meat. PMID:25083110

  4. Airborne particulate endocrine disrupting compounds in China: Compositions, size distributions and seasonal variations of phthalate esters and bisphenol A

    NASA Astrophysics Data System (ADS)

    Li, Jianjun; Wang, Gehui

    2015-03-01

    Phthalate esters and bisphenol A (BPA) are endocrine disrupting compounds (EDCs) and ubiquitously occur in the environment. In the past decade we have characterized atmospheric organic aerosols from various environments (e.g., urban, rural, mountain and marine) of East Asia on a molecular level, but not investigated EDCs in the samples. In the current study we re-analyzed our database for concentrations, compositions and size distributions of phthalates and BPA and compared with those in the literature to improve the understanding on air pollution status in China. Our results showed that airborne particulate phthalates and BPA are 63-1162 ng m- 3 and 1.0-20 ng m- 3 in the urban regions in China, respectively, being one to two orders of magnitude higher than those in the developed countries. Among the detected phthalates in Chinese urban areas, bis(2-ethylhexyl) phthalate (BEHP) is the predominant congener, contributing to 23-79% (ave. 53 ± 15%) of the total phthalates. Concentrations of phthalates and bisphenol A in Shanghai and Xi'an (two mega-cities in China) in 2009 were 3-84% lower than those in 2003, probably indicating a positive effect of the government's air pollution control in the recent years. Phthalates are higher in summer than in winter, because they are not chemically bonded to the polymeric matrix and more easily evaporate into the air under higher temperature conditions. Based on the size distribution observation, we found that diisobutyl and dibutyl phthalates mainly exist in coarse particles because of high volatilities, in contrast to BEHP and BPA, which are dominant in fine particles due to less volatility. Our results also indicate that BPA is mostly derived from the open burning of solid waste while phthalates are derived from both direct evaporation from the matrix and solid waste combustion.

  5. Assessing Community-Level and Single-Species Models Predictions of Species Distributions and Assemblage Composition after 25 Years of Land Cover Change

    PubMed Central

    Bonthoux, Sébastien; Baselga, Andrés; Balent, Gérard

    2013-01-01

    To predict the impact of environmental change on species distributions, it has been hypothesized that community-level models could give some benefits compared to species-level models. In this study we have assessed the performance of these two approaches. We surveyed 256 bird communities in an agricultural landscape in southwest France at the same locations in 1982 and 2007. We compared the ability of CQO (canonical quadratic ordination; a method of community-level GLM) and GLMs (generalized linear models) to i) explain species distributions in 1982 and ii) predict species distributions, community composition and species richness in 2007, after land cover change. Our results show that models accounting for shared patterns between species (CQO) slightly better explain the distribution of rare species than models that ignore them (GLMs). Conversely, the predictive performances were better for GLMs than for CQO. At the assemblage level, both CQO and GLMs overestimated species richness, compared with that actually observed in 2007, and projected community composition was only moderately similar to that observed in 2007. Species richness projections tended to be more accurate in sites where land cover change was more marked. In contrast, the composition projections tended to be less accurate in those sites. Both modelling approaches showed a similar but limited ability to predict species distribution and assemblage composition under conditions of land cover change. Our study supports the idea that our community-level model can improve understanding of rare species patterns but that species-level models can provide slightly more accurate predictions of species distributions. At the community level, the similar performance of both approaches for predicting patterns of assemblage variation suggests that species tend to respond individualistically or, alternatively, that our community model was unable to effectively account for the emergent community patterns. PMID:23349818

  6. Habitat stress initiates changes in composition, CO2 gas exchange and C-allocation as life traits in biological soil crusts.

    PubMed

    Colesie, Claudia; Green, T G Allan; Haferkamp, Ilka; Büdel, Burkhard

    2014-10-01

    Biological soil crusts (BSC) are the dominant functional vegetation unit in some of the harshest habitats in the world. We assessed BSC response to stress through changes in biotic composition, CO2 gas exchange and carbon allocation in three lichen-dominated BSC from habitats with different stress levels, two more extreme sites in Antarctica and one moderate site in Germany. Maximal net photosynthesis (NP) was identical, whereas the water content to achieve maximal NP was substantially lower in the Antarctic sites, this apparently being achieved by changes in biomass allocation. Optimal NP temperatures reflected local climate. The Antarctic BSC allocated fixed carbon (tracked using (14)CO2) mostly to the alcohol soluble pool (low-molecular weight sugars, sugar alcohols), which has an important role in desiccation and freezing resistance and antioxidant protection. In contrast, BSC at the moderate site showed greater carbon allocation into the polysaccharide pool, indicating a tendency towards growth. The results indicate that the BSC of the more stressed Antarctic sites emphasise survival rather than growth. Changes in BSC are adaptive and at multiple levels and we identify benefits and risks attached to changing life traits, as well as describing the ecophysiological mechanisms that underlie them. PMID:24694713

  7. Spatial Distribution of Biochemical Parameters Indicating Biomass and Community Composition of Microbial Assemblies In Estuarine Mud Flat Sediments

    PubMed Central

    Federle, Thomas W.; Hullar, Meredith A.; Livingston, Robert J.; Meeter, Duane A.; White, David C.

    1983-01-01

    The spatial distribution of communities was examined in estuarine mud flat sediments by the biochemical analysis of the lipids and lipid components extracted from the sediments. Total phospholipid was used as a measure of total biomass, and fatty acids were used as indicators of community composition. Comparisons were made among 2- by 2-m (location) and 0.2- by 0.2-m (cluster) sampling plots by using a nested analysis of variance to design an optimal sampling strategy to define the microbial content of a large, relatively homogenous area. At two of the three stations, a 2- by 2-m plot was representative of the station, but 0.2- by 0.2-m areas were in no case representative of the station. The biomass measured by the extractable phospholipid and the total lipid palmitic acid showed excellent correlation with the fatty acid “signatures” characteristic of bacteria, but showed a lower correlation with the long-chain polyenoic fatty acids characteristic of the microfauna. PMID:16346181

  8. Fast changes in chemical composition and size distribution of fine particles during the near-field transport of industrial plumes.

    PubMed

    Marris, Hélène; Deboudt, Karine; Augustin, Patrick; Flament, Pascal; Blond, François; Fiani, Emmanuel; Fourmentin, Marc; Delbarre, Hervé

    2012-06-15

    Aerosol sampling was performed inside the chimneys and in the close environment of a FeMn alloys manufacturing plant. The number size distributions show a higher abundance of ultrafine aerosols (10-100 nm) inside the plume than upwind of the plant, indicating the emissions of nanoparticles by the industrial process. Individual analysis of particles collected inside the plume shows a high proportion of metal bearing particles (Mn-/Fe-) consisting essentially of internally mixed aluminosilicate and metallic compounds. These particles evolve rapidly (in a few minutes) after emission by adsorption of VOC gas and sulfuric acid emitted by the plant but also by agglomeration with pre-existing particles. At the moment, municipalities require a monitoring of industrial emissions inside the chimneys from manufacturers. However those measures are insufficient to report such rapid changes in chemical composition and thus to evaluate the real impact of industrial plumes in the close environment of plants (when those particles leave the industrial site). Consequently, environmental authorities will have to consider such fast evolutions and then to adapt future regulations on air pollution sources. PMID:22542297

  9. Ion acceleration in Ar-Xe and Ar-He plasmas. I. Electron energy distribution functions and ion composition

    SciTech Connect

    Biloiu, Ioana A.; Scime, Earl E. [Department of Physics, West Virginia University, Morganton, West Virginia 26506 (United States)

    2010-11-15

    Electron energy distribution functions (eedf), ion production, and ion composition are studied in Ar-Xe and Ar-He expanding helicon plasmas. It was found that under the conditions of constant total flow rate, Xe, in addition to Ar, changes the eedf from Maxwellian-like to Druyvesteyn-like with a shortening of the high energy tail at {approx}15 eV. The electron temperature exponentially decreases from {approx}7 eV in pure Ar plasma to {approx}4 eV in pure Xe plasma. Xenon ions dominate the ion population for Xe filling fractions greater than 10%. The plasma density increases by {approx}15% with increasing Xe fraction. For an Ar-He plasma, increasing the helium fraction increases the electron temperature from {approx}7 eV in pure Ar plasma to {approx}14 eV for a He filling fraction of 80%. The plasma density drops by more than three orders of magnitude from 1.14x10{sup 11} cm{sup -3} to 6.5x10{sup 7} cm{sup -3}. However, the inferred ion densities indicate that even at a helium fraction of 80%, argon ions significantly outnumber helium ions.

  10. Seasonal trends in the social composition and inside-trunk distribution of Kalotermes flavicollis (Isoptera: Kalotermitidae) colonizing grapevines.

    PubMed

    Maistrello, Lara; Ocete, Rafael; López, M Angeles

    2010-04-01

    The polyphagous drywood termite Kalotermes flavicollis (Fabricius) can establish its colonies inside living trees, causing a progressive debilitation that ends with the death of the plant. For this reason, it is considered one of the major pests of Sherry vineyards in Andalusia, SW Spain. To analyze the trends of colonization of this termite, a detailed investigation was performed during 16 mo in seven districts of the Sherry area, cutting randomly selected grapevine trunks into six sections, from which all individuals were collected and counted according to their developmental instar or caste. The results detected variations in the social composition of the groups colonizing grapevines according to the spatial distribution inside the vine trunk and in the numerical trends over the seasons. A pattern of seasonal migrations of the termites inside the trunk was inferred, with upward movements from spring to autumn and downward movements from autumn to winter. During winter, when termites were mainly located in the medium-basal sections of the trunk, a higher proportion of eggs and larvae was detected. Going from spring to summer, when the majority of the termites was located in the medium-upper sections of the trunk, there was an increase of nymphal instars followed, during autumn, by the appearance of alates, mostly located in the upper sections of the grapevine. Pseudergates and reproductives maintained their proportions and locations almost unchanged during the year. PMID:20388256

  11. Evaluation of the Fiber Stress Distribution in Aramid/Epoxy Model Composite Using Micro-Raman Spectroscopy and FEM Analysis

    NASA Astrophysics Data System (ADS)

    Tanaka, Kazuto; Minoshima, Kohji; Yamada, Hideo

    A single-fiber pull-out model composite for an aramid/epoxy system was specially designed to measure the stress distribution of the aramid fiber embedded in the matrix using micro-Raman spectroscopy. The stress transfer length of the fiber obtained was about 400-500 ?m, which was equal to the result of FEM analysis. Just after the initiation and propagation of the fiber/matrix interfacial debonding, the fiber was broken, and the fiber in the matrix had the axial tensile residual stress. The tensile residual axial stress showed the maximum at around the tip of the interfacial debonding. The stress was reduced after the specimen was kept in air at 80°C for 44h, and it became almost equal to zero after being immersed in deionized water at 80°C for 44h. This behavior agreed with the result of FEM analysis, in which the friction coefficient was introduced in the fiber/matrix interface. The axial residual stress was caused by the friction between the fiber and matrix, due to the compressive stress acting between the resin and the fiber, which was caused by the difference of the coefficient of thermal expansion.

  12. Life cycle of Pseudocalanus acuspes Giesbrecht (Copepoda, Calanoida) in the Central Baltic Sea: I. Seasonal and spatial distribution

    Microsoft Academic Search

    Jasmin Renz; Hans-Jürgen Hirche

    2006-01-01

    The seasonal and spatial distribution of Pseudocalanus acuspes in the Bornholm Basin (Central Baltic Sea) was studied on 16 cruises between March 2002 and May 2003 from stratified (10 m)\\u000a multinet samples. The highest abundances were reached in May 2002 and April 2003 (618×103 and 869×103 ind. m?2, respectively). Ontogenetic vertical distribution was stage specific with differences of mean annual weighted mean depth

  13. Integration of Cu-coated single-mode optical fiber into carbon/PEEK composite for distributed structural health monitoring based on Rayleigh backscatter reflectometry

    NASA Astrophysics Data System (ADS)

    Steffen, Milan; Schukar, Marcus

    2013-05-01

    In this paper a technique for integrating copper coated silica optical fibers into AS-4/PEEK composite for Structural Health Monitoring (SHM) is presented. The integration steps are described in detail. X-ray and microscopic images indicate a successfully integrated optical fiber which does not seem to affect the fiber/matrix distribution around it. Optical backscatter reflectometry shows losses of approximately 2dBm-1 along the integrated parts of the optical fiber due to temperature induced shrinkage of the composite.

  14. Recent advancement in optical fiber sensing for aerospace composite structures

    NASA Astrophysics Data System (ADS)

    Minakuchi, Shu; Takeda, Nobuo

    2013-12-01

    Optical fiber sensors have attracted considerable attention in health monitoring of aerospace composite structures. This paper briefly reviews our recent advancement mainly in Brillouin-based distributed sensing. Damage detection, life cycle monitoring and shape reconstruction systems applicable to large-scale composite structures are presented, and new technical concepts, "smart crack arrester" and "hierarchical sensing system", are described as well, highlighting the great potential of optical fiber sensors for the structural health monitoring (SHM) field.

  15. Life Cycle Assessment of the District Heat Distribution System. Part 3: Use Phase and Overall Discussion (10 pp)

    Microsoft Academic Search

    Camilla Persson; Morgan Fröling; Magdalena Svanström

    2006-01-01

    -  Part 1: Pipe Production [Int J LCA 9 (2) 130-136 (2004)]\\u000a Part 2: Network Construction [Int J LCA 10 (6) 425-435 (2005)]\\u000a Part 3: Use Phase and Overall Discussion [DOI: http:\\/\\/dx.doi.org\\/10.1065\\/lca2005.08.225]\\u000a \\u000a \\u000a \\u000a -  Preamble. This series of three papers is based on research performed for the Swedish District Heating Association with the\\u000a purpose of mapping the environmental life cycle impacts from the

  16. DataONE: A Distributed Environmental and Earth Science Data Network Supporting the Full Data Life Cycle

    NASA Astrophysics Data System (ADS)

    Cook, R.; Michener, W.; Vieglais, D.; Budden, A.; Koskela, R.

    2012-04-01

    Addressing grand environmental science challenges requires unprecedented access to easily understood data that cross the breadth of temporal, spatial, and thematic scales. Tools are needed to plan management of the data, discover the relevant data, integrate heterogeneous and diverse data, and convert the data to information and knowledge. Addressing these challenges requires new approaches for the full data life cycle of managing, preserving, sharing, and analyzing data. DataONE (Observation Network for Earth) represents a virtual organization that enables new science and knowledge creation through preservation and access to data about life on Earth and the environment that sustains it. The DataONE approach is to improve data collection and management techniques; facilitate easy, secure, and persistent storage of data; continue to increase access to data and tools that improve data interoperability; disseminate integrated and user-friendly tools for data discovery and novel analyses; work with researchers to build intuitive data exploration and visualization tools; and support communities of practice via education, outreach, and stakeholder engagement.

  17. The Composition of Bovine Peritubular Dentin: Matching TOF-SIMS, Scanning Electron Microscopy and Biochemical Component Distributions

    PubMed Central

    Gotliv, Bat Ami; Veis, Arthur

    2008-01-01

    Peritubular dentin (PTD) is a hypermineralized phase within the dentinal tubules in some vertebrate teeth as an interface between the intertubular dentin (ITD) and the cell processes. Our aim has been to understand the composition, structure and role of PTD as a mineralized tissue. We have utilized the technique of time of flight secondary ion mass spectrometry (TOF-SIMS) to map the distribution of positive and negative inorganic ions as well as organic components in the fully mineralized, intact PTD structure in bovine tooth cross-sections, and correlated these with scanning electron microscopy (SEM) in standard and backscatter modes. In recent work, we developed a procedure to freeze fracture the teeth and separate PTD from the less dense ITD by the use of aqueous sodium phosphotungstate step density gradients, after degrading the ITD collagen with NaOCl. Here, PTD-containing fragments were characterized by SEM and TOF-SIMS surface structure analysis. The TOF-SIMS data show that the isolated PTD does not contain collagen, but its surface is rich in glutamic acid-containing protein(s). The TOF-SIMS spectra also indicated that the intact PTD fragments contain phospholipids, and chemical analyses showed phosphatidylserine, phosphatidylinositol and phosphatidylcholine as the principal lipid components. In SEM sections, untreated PTD shows as a smooth collar around the tubule, but after digestion with ethylenediamine to remove all organic components, the porous nature of the mineral phase of small, thin platy apatite crystals becomes evident. Thus, the organic matrix of PTD appears to be a proteolipid-phospholipid complex. PMID:18728348

  18. Individual Aerosol Particles from Biomass Burning in Southern Africa. 1; Compositions and Size Distributions of Carbonaceous Particles

    NASA Technical Reports Server (NTRS)

    Posfai, Mihaly; Simonics, Renata; Li, Jia; Hobbs, Peter V.; Buseck, Peter R.

    2003-01-01

    Individual aerosol particles in smoke plumes from biomass fires and in regional hazes in southern Africa were studied using analytical transmission electron microscopy (TEM), which allowed detailed characterization of carbonaceous particle types in smoke and determination of changes in particle properties and concentrations during smoke aging. Based on composition, morphology, and microstructure, three distinct types of carbonaceous particles were present in the smoke: organic particles with inorganic (K-salt) inclusions, tar ball particles, and soot. The relative number concentrations of organic particles were largest in young smoke, whereas tar balls were dominant in a slightly aged (1 hour) smoke from a smoldering fire. Flaming fires emitted relatively more soot particles than smoldering fires, but soot was a minor constituent of all studied plumes. Further aging caused the accumulation of sulfate on organic and soot particles, as indicated by the large number of internally mixed organic/sulfate and soot/sulfate particles in the regional haze. Externally mixed ammonium sulfate particles dominated in the boundary layer hazes, whereas organic/sulfate particles were the most abundant type in the upper hazes. Apparently, elevated haze layers were more strongly affected by biomass smoke than those within the boundary layer. Based on size distributions and the observed patterns of internal mixing, we hypothesize that organic and soot particles are the cloud-nucleating constituents of biomass smoke aerosols. Sea-salt particles dominated in the samples taken in stratus clouds over the Atlantic Ocean, off the coast of Namibia, whereas a distinct haze layer above the clouds consisted of aged biomass smoke particles.

  19. The measurement of compositions and the isotopic distribution of released fission gas in the fuel rods of pressurized water reactors (PWR) of Korea

    Microsoft Academic Search

    S. D. Park; D. K. Min; Y. K. Ha; K. Song

    2010-01-01

    In this work the analysis procedures of fission gas compositions and their isotopic distributions using a gas chromatography\\u000a (GC) system and\\/or a quadrupole mass spectrometer (QMS) system were established, and their analysis results were reviewed\\u000a in order to evaluate their analytical performance. Also, the accumulated data, up to now, regarding fission gas measurement\\u000a were reviewed to discern any irradiation histories

  20. A comparison of phytoplankton size-fractions in Mondsee, an alpine lake in Austria: distribution, pigment composition and primary production rates

    Microsoft Academic Search

    Sonja Greisberger; Martin T. Dokulil; Katrin Teubner

    2008-01-01

    Production rates, abundance, chlorophyll a (Chl a) concentrations and pigment composition were measured for three size classes (11 ?m) of phytoplankton\\u000a from May to December 2000 in deep, mesotrophic, alpine lake Mondsee in Austria. The study focuses on differences among phytoplankton\\u000a size fractions characterised by their surface area to volume ratio ([mm2 l?1: mm3l?1]), pigment distribution patterns and photosynthetic rates. Particular attention

  1. Spatial distribution, diversity and composition of bacterial communities in sub-seafloor fluids at a deep-sea hydrothermal field of the Suiyo Seamount

    Microsoft Academic Search

    Shingo Kato; Kurt Hara; Hiroko Kasai; Takashi Teramura; Michinari Sunamura; Jun-Ichiro Ishibashi; Takeshi Kakegawa; Toshiro Yamanaka; Hiroyuki Kimura; Katsumi Marumo; Tetsuro Urabe; Akihiko Yamagishi

    2009-01-01

    Spatial distribution, diversity, and composition of bacterial communities within the shallow sub-seafloor at the deep-sea hydrothermal field of the Suiyo Seamount, Izu-Bonin Arc, Western Pacific Ocean, were investigated. Fluids were sampled from four boreholes in this area. Each borehole was located near or away from active vents, the distance ranging 2–40m from active vents. In addition, fluids discharging from a

  2. Vertical distribution, population structure and life cycles of four oncaeid copepods in the Oyashio region, western subarctic Pacific

    Microsoft Academic Search

    Yuichiro Nishibe; Tsutomu Ikeda

    2007-01-01

    Vertical distribution and population structure of four dominant oncaeid copepods (Triconia borealis, Triconia canadensis, Oncaea grossa and Oncaea parila) were investigated in the Oyashio region, western subarctic Pacific. Seasonal samples were collected with 0.06 mm mesh nets\\u000a from five discrete layers between the surface and 2,000 m depth at seven occasions (March, May, June, August and October 2002,\\u000a December 2003 and February

  3. Vertical distribution, population structure and life cycles of four oncaeid copepods in the Oyashio region, western subarctic PaciWc

    Microsoft Academic Search

    Yuichiro Nishibe; Tsutomu Ikeda

    2007-01-01

    Vertical distribution and population struc- ture of four dominant oncaeid copepods (Triconia borealis, Triconia canadensis, Oncaea grossa and Oncaea parila) were investigated in the Oyashio region, western subarctic PaciWc. Seasonal samples were collected with 0.06 mm mesh nets from Wve dis- crete layers between the surface and 2,000 m depth at seven occasions (March, May, June, August and Octo- ber

  4. 27Student Life Student Life

    E-print Network

    Dresden, Gregory

    26 III Student LIfe #12;27Student Life Student Life The and recreational phases of their college experience. Thesamecodeofhonorthatgovernsacademic life also governs's superior academic preparation com- bined with the character-building responsibilities of student life mark

  5. Kinetics and product distribution of end of life tyres (ELTs) pyrolysis: a novel approach in polyisoprene and SBR thermal cracking.

    PubMed

    Al-Salem, S M; Lettieri, P; Baeyens, J

    2009-12-30

    Thermo-chemical treatments (mainly pyrolysis) directed towards energy and products recovery provide a very promising alternative to open space disposal or landfilling, reducing in the process hazardous waste and potential contamination to soil and water resources. In this communication, we present results of end of life tyres (ELTs) pyrolysis via isothermal and dynamic thermogravimetry of two ELT grades. The aim of this study is to demonstrate the possibility of utilizing a pre-set temperature (T(c)=500 degrees C) pyrolysis process (conversion time, t(c), of 120 s), to the benefit of intensifying the global product yields recovered. A novel engineering kinetics approach was undertaken to propose a thermal cracking scheme of four primary and two secondary side reactions. Thermal degradation of ELTs was taken from a depolymerization approach of the present polyisoprene polymer in the tyres, resulting in a high regression of 0.959. The products of ELTs pyrolysis were lumped into four categories, namely aromatics, liquids, char and gases. The thermal cracking model evaluation of kinetic rate constants and lumped products showed a regression ranging between 0.90 and 0.94. Dynamic runs were performed to extend the model derived, taking into account heating rate (beta) influence and products prediction and interaction. The results obtained can be used in designing industrial ELTs pyrolysis units. PMID:19713038

  6. Chemical composition, mass size distribution and source analysis of long-range transported wildfire smokes in Helsinki.

    PubMed

    Sillanpää, Markus; Saarikoski, Sanna; Hillamo, Risto; Pennanen, Arto; Makkonen, Ulla; Spolnik, Zoya; Van Grieken, René; Koskentalo, Tarja; Salonen, Raimo O

    2005-11-01

    Special episodes of long-range transported particulate (PM) air pollution were investigated in a one-month field campaign at an urban background site in Helsinki, Finland. A total of nine size-segregated PM samplings of 3- or 4-day duration were made between August 23 and September 23, 2002. During this warm and unusually dry period there were two (labelled P2 and P5) sampling periods when the PM2.5 mass concentration increased remarkably. According to the hourly-measured PM data and backward air mass trajectories, P2 (Aug 23-26) represented a single, 64-h episode of long-range transported aerosol, whereas P5 (Sept 5-9) was a mixture of two 16- and 14-h episodes and usual seasonal air quality. The large chemical data set, based on analyses made by ion chromatography, inductively coupled plasma mass spectrometry, X-ray fluorescence analysis and smoke stain reflectometry, demonstrated that the PM2.5 mass concentrations of biomass signatures (i.e. levoglucosan, oxalate and potassium) and of some other compounds associated with biomass combustion (succinate and malonate) increased remarkably in P2. Crustal elements (Fe, Al, Ca and Si) and unidentified matter, presumably consisting to a large extent of organic material, were also increased in P2. The PM2.5 composition in P5 was different from that in P2, as the inorganic secondary aerosols (NO3-, SO4(2-), NH4+) and many metals reached their highest concentration in this period. The water-soluble fraction of potassium, lead and manganese increased in both P2 and P5. Mass size distributions (0.035-10 microm) showed that a large accumulation mode mainly caused the episodically increased PM2.5 concentrations. An interesting observation was that the episodes had no obvious impact on the Aitken mode. Finally, the strongly increased concentrations of biomass signatures in accumulation mode proved that the episode in P2 was due to long-range transported biomass combustion aerosol. PMID:16227078

  7. Soybean Root Suberin: Anatomical Distribution, Chemical Composition, and Relationship to Partial Resistance to Phytophthora sojae 1[W][OA

    PubMed Central

    Thomas, Raymond; Fang, Xingxiao; Ranathunge, Kosala; Anderson, Terry R.; Peterson, Carol A.; Bernards, Mark A.

    2007-01-01

    Soybean (Glycine max L. Merr.) is a versatile and important agronomic crop grown worldwide. Each year millions of dollars of potential yield revenues are lost due to a root rot disease caused by the oomycete Phytophthora sojae (Kaufmann & Gerdemann). Since the root is the primary site of infection by this organism, we undertook an examination of the physicochemical barriers in soybean root, namely, the suberized walls of the epidermis and endodermis, to establish whether or not preformed suberin (i.e. naturally present in noninfected plants) could have a role in partial resistance to P. sojae. Herein we describe the anatomical distribution and chemical composition of soybean root suberin as well as its relationship to partial resistance to P. sojae. Soybean roots contain a state I endodermis (Casparian bands only) within the first 80 mm of the root tip, and a state II endodermis (Casparian bands and some cells with suberin lamellae) in more proximal regions. A state III endodermis (with thick, cellulosic, tertiary walls) was not present within the 200-mm-long roots examined. An exodermis was also absent, but some walls of the epidermal and neighboring cortical cells were suberized. Chemically, soybean root suberin resembles a typical suberin, and consists of waxes, fatty acids, ?-hydroxy acids, ?,?-diacids, primary alcohols, and guaiacyl- and syringyl-substituted phenolics. Total suberin analysis of isolated soybean epidermis/outer cortex and endodermis tissues demonstrated (1) significantly higher amounts in the endodermis compared to the epidermis/outer cortex, (2) increased amounts in the endodermis as the root matured from state I to state II, (3) increased amounts in the epidermis/outer cortex along the axis of the root, and (4) significantly higher amounts in tissues isolated from a cultivar (‘Conrad’) with a high degree of partial resistance to P. sojae compared with a susceptible line (OX760-6). This latter correlation was extended by an analysis of nine independent and 32 recombinant inbred lines (derived from a ‘Conrad’ × OX760-6 cross) ranging in partial resistance to P. sojae: Strong negative correlations (?0.89 and ?0.72, respectively) were observed between the amount of the aliphatic component of root suberin and plant mortality in P. sojae-infested fields. PMID:17494920

  8. Chemical composition and mass size distribution of PM1.0 at an elevated site in central east China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. M.; Zhang, X. Y.; Sun, J. Y.; Hu, G. Y.; Shen, X. J.; Wang, Y. Q.; Wang, T. T.; Wang, D. Z.; Zhao, Y.

    2014-06-01

    Size-resolved aerosol chemical compositions were measured continuously for one and half years with an aerosol mass spectrometer (AMS) to characterize the mass and size distributions (MSDs) of each component in bulk, fresh and aged submicron particles (approximately PM1.0) at Mountain Tai, an elevated site in Central East China (CEC) from June 2010 to January 2012. The majority of the regionally-dispersed aerosols were found to be contributed from short distance mixed aerosol, mostly from its south with organics and sulfate as the major components. The annual mean mass concentrations of organics, sulfate, nitrate, ammonium and chloride were 11.2, 9.2, 7.2, 5.8 and 0.95 ?g m-3, respectively, which are much lower for organics and sulfate, and slightly lower for nitrate, ammonium and chloride than those at the nearby surface rural sites. High organics were observed for all four seasons, and the relatively fresh organic aerosol (OA) containing high proportion of less-photo chemically OA, were found from long-range transported aerosol from northwest. Semi-volatile and low-volatile oxidized OAs together contributed approximately 49%, 55% in spring and 72% and 51% in winter of total OA, showing at least 50% of OA can be attributable to SOA. Seasonally, the chemical components at the elevated site showed a "winter high and autumn low" pattern, with organics, sulfate and ammonium peaking in summer. Though no obvious differences of MSDs were seen for various chemical components in the planetary boundary layer (PBL) and free troposphere (FT), the concentrations were a factor of 5-7 higher in PBL than in FT. The averaged MSDs of particles between 30-1000 nm for organics, sulfate, nitrate, and ammonium are approximately log-normal with similar mass median diameters (MMDs) of 539, 585, 542, and 545 nm, respectively, which were slightly larger than those in ground sites within North China Plain (NCP). Obvious differences in MMDs were found between fresh and aged aerosols for sulfate and ammonium, with smaller increased size-factors for the Mt. Tai aerosols than those in less polluted areas. All these exhibit the relative aged and well-mixed aerosol observed.

  9. Solid-shell element model of assumed through-thickness electric distribution for laminate composite piezoelectric structures

    E-print Network

    Yi, Sung

    The eight-node solid-shell finite element models have been developed for the analysis of laminated composite pate/shell structures with piezoelectric actuators and sensors. To resolve the locking problems of the solid-shell ...

  10. Distribution patterns of small-molecule ligands in the protein universe and implications for origin of life and drug discovery

    PubMed Central

    Ji, Hong-Fang; Kong, De-Xin; Shen, Liang; Chen, Ling-Ling; Ma, Bin-Guang; Zhang, Hong-Yu

    2007-01-01

    Background Extant life depends greatly on the binding of small molecules (such as ligands) with macromolecules (such as proteins), and one ligand can bind multiple proteins. However, little is known about the global patterns of ligand-protein mapping. Results By examining 2,186 well-defined small-molecule ligands and thousands of protein domains derived from a database of druggable binding sites, we show that a few ligands bind tens of protein domains or folds, whereas most ligands bind only one, which indicates that ligand-protein mapping follows a power law. Through assigning the protein-binding orders (early or late) for bio-ligands, we demonstrate that the preferential attachment principle still holds for the power-law relation between ligands and proteins. We also found that polar molecular surface area, H-bond acceptor counts, H-bond donor counts and partition coefficient are potential factors to discriminate ligands from ordinary molecules and to differentiate super ligands (shared by three or more folds) from others. Conclusion These findings have significant implications for evolution and drug discovery. First, the chronology of ligand-protein binding can be inferred by the power-law feature of ligand-protein mapping. Some nucleotide-containing ligands, such as ATP, ADP, GDP, NAD, FAD, dihydro-nicotinamide-adenine-dinucleotide phosphate (NDP), nicotinamide-adenine-dinucleotide phosphate (NAP), flavin mononucleotide (FMN) and AMP, are found to be the earliest cofactors bound to proteins, agreeing with the current understanding of evolutionary history. Second, the finding that about 30% of ligands are shared by two or more domains will help with drug discovery, such as in finding new functions from old drugs, developing promiscuous drugs and depending more on natural products. PMID:17727706

  11. Simultaneous Elemental Composition and Size Distributions of Submicron Particles in Real Time Using Laser Atomization Ionization Mass Spectrometry

    Microsoft Academic Search

    William D. Reents; Zhaozhu Ge

    2000-01-01

    Composition and size of individual submicron particles have been measured using a laser atomization ionization mass spectrometry technique, the Particle Blaster. Individual particles are quantitatively converted to atomic cations, providing information on both their complete elemental composition and particle size. Measured average atomic ratios for 100 nm particles of sodium chloride is 1.12 +- 0.36 (Cl:Na), for 50 nm particles

  12. Species composition and distributions of mesopelagic fishes over the slope of the north-central Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Ross, Steve W.; Quattrini, Andrea M.; Roa-Varón, Adela Y.; McClain, Jennifer P.

    2010-11-01

    Midwater fish faunas over three cold seep habitats >1000 m (AC601, GC852, AT340) and over a cold-water coral bank (VK826, <1000 m) in the north-central Gulf of Mexico (GOM) are described and compared. Day and night discrete-depth sampling was accomplished at each study site, 9-29 August 2007, using an opening-closing Tucker trawl towed at depth for 30 min. The 159 Tucker trawl stations yielded 9802 individuals and at least 126 species (30 families) of juvenile and adult midwater fishes. Myctophidae (38 species, 28% of the total catch), Stomiidae (17 species, 1.4%), Gonostomatidae (12 species, 56%), Sternoptychidae (10 species, 6%), and Phosichthyidae (5 species, 6%) dominated catches at all sites. Thirty-one species (8 families) comprised about 90% of the overall abundance of fishes across the four sites. Despite the wide separation of study sites and some differences in physical oceanography, geographic and temporal patterns in mesopelagic fish assemblages were not evident (ANOSIM, Global R=0.20, p=0.1%, pairwise R values <0.3). However, station groupings were related mostly to similarities in sampled depths (SIMPROF, p<1.5%). Upper water-column station groups (<400 m) were typified by Lepidophanes guentheri, Diaphus dumerilii, Vinciguerria nimbaria, Vinciguerria poweriae, Valenciennellus tripunctulatus, Argyropelecus aculeatus, Notolychnus valdiviae, Benthosema suborbitale, Gonostoma elongatum, and Hygophum taaningi. Deeper station groups (mean depth=609 m) were typified by Cyclothone alba, Cyclothone acclinidens, Cyclothone braueri, Cyclothone obscura, Cyclothone pallida, Cyclothone pseudopallida, V. tripunctulatus, and Hygophum benoiti. Depth, diel, and size distributions were also analyzed for abundant species. For example, Cyclothone spp., abundant at all sites except VK826, usually occurred in deeper waters (>130 m), especially during daylight hours (>335 m). Most Cyclothone individuals were captured at night at GC852, whereas catches were more evenly distributed across times at AT340 and VK826. Cyclothone spp. individuals occurred in the deeper parts of the sampled depth range at AT340 and VK826 at all times compared with GC852, where they appeared to undergo a diel migration. The two most abundant Cyclothone spp., C. pallida and C. pseudopallida, had the broadest depth ranges (150-1377 m) and exhibited a trend for larger specimens to occur deeper at GC852. Most V. tripunctulatus were captured at night and tended to have larger mean sizes in deeper waters. This species did not exhibit strong diel patterns of vertical distribution. Shallower depths were occupied at night by some individuals at all sites, but most individuals remained somewhat deeper at night at VK826 (350-450 m at night and 200-350 m by day) and AT340 (200-600 m at night and 300-500 m by day) compared with GC852 (150-450 m at night and 750 and 1000 m by day). Nearly all Vinciguerria poweriae were caught at night, and no clear trend of size with depth was apparent. This species occupied a wider depth range at night, with most in the upper 200 m. Most myctophids, the strongest diel migrators, were captured at night at the offshore stations. The dominant myctophid, N. valdiviae, was most abundant at GC852 (550-1050 m by day and 50-750 m at night), but diel movement was more distinct at AT340 (<200 m at night and 350-500 m by day). No size-related trends with depth were apparent at any site for N. valdiviae, and size distributions were similar among sites. This study and others support the hypothesis that there is a geographically similar mesopelagic fish fauna throughout the GOM. However, the fauna does vary by depth, with some species remaining in deep waters at all times (e.g., Cyclothone spp.) and others occurring at mid-depths and exhibiting varying degrees of diel migration (e.g., many myctophids). Even though faunal composition is similar across the GOM, some species exhibit different movement behaviors at different locations. Such variances could be related to differences in physical or chemical factors, food re

  13. Aircraft wheel life assessment

    Microsoft Academic Search

    B. F. Spencer Jr.; D. J. Kirkner; E. E. Schudt; S. Kandarpa

    1993-01-01

    The important part of wheel life assessment problems is the accurate determination of the tire\\/wheel interface pressure distribution under various loading conditions. A combined analytical\\/experimental methodology for obtaining this pressure distribution was developed. The principal analytical tool in this methodology is the finite element program ANTWILL (Analysis of Tire Wheel Interface Loads) which recovers the pressure distribution given a number

  14. A novel approach to predict the pin load distribution of multiple bolt-jointed composite laminate based on the circuit model

    NASA Astrophysics Data System (ADS)

    Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao

    2011-11-01

    The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.

  15. A novel approach to predict the pin load distribution of multiple bolt-jointed composite laminate based on the circuit model

    NASA Astrophysics Data System (ADS)

    Yang, Xiankun; Chen, Haoyuan; Cheng, Linan; Zheng, Xitao

    2012-04-01

    The circuit model was applied to predict the pin load distribution of composite multiple bolt-joint structure. The load, flexibility and deformation of the mechanics model were equivalent to the current, resistance and voltage of the circuit model, respectively. Based on the above assumption, it could be found that the Hooke's law and the deformation compatibility equation in the origin mechanics model transformed into the Ohm's law and the voltage balance equation in the new circuit model. This approach translated the complex model of composite multiple bolt-jointed into a simple circuit model which consisted of some series circuits and parallel circuits. The analysis of the new circuit model had formed n-1 independence voltage balance equations and a current balance equation, thus, the current and load of each bolt could be calculated. In the new model, power sources which were added as required in some branch circuits could also simulate the clearance or interference in the origin model. Compared with the result of the multiple bolt-joints composite laminate test, the new approach could make an excellent performance to estimate the load distribution.

  16. Aspects of the study of the life cycles of Antarctic copepods

    Microsoft Academic Search

    Sigrid B. Schnack-Schiel

    2001-01-01

    Different approaches to the study of life cycle strategies of Antarctic copepods are described in an attempt to shed new light on our present knowledge. To date, most studies were carried out on abundance, horizontal and vertical distribution and stage composition during different seasons and in various regions. Hence, the seasonal pictures had to be compiled from different years and

  17. Nano-sized Li-Fe composite oxide prepared by a self-catalytic reverse atom transfer radical polymerization approach as an anode material for lithium-ion batteries

    SciTech Connect

    Yue, G.Q.; Liu, C.; Wang, D.Z. [CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China)] [CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Wang, Y.; Yuan, Q.F.; Xu, R.; Zhao, F.G. [Amperex Technology Ltd, Guanggong Dongguan 523080 (China)] [Amperex Technology Ltd, Guanggong Dongguan 523080 (China); Chen, C.H., E-mail: cchchen@ustc.edu.cn [CAS Key Laboratory of Materials for Energy Conversions, Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China)

    2010-09-15

    A novel Self-catalytic Reverse Atom Transfer Radical Polymerization (RATRP) approach that can provide the radical initiator and the catalyst by the system itself is used to synthesize a nano-sized Li-Fe composite oxide powder in large scale. Its crystalline structure and morphology have been characterized by X-ray diffraction and scanning electron microscopy. The results reveal that the composite is composed of nano-sized LiFeO{sub 2} and Fe{sub 3}O{sub 4}. Its electrochemical properties are evaluated by charge/discharge measurements. The results show that the Li-Fe composite oxide is an excellent anode material for lithium-ion batteries with good cycling performance (1249 mAh g{sup -1} at 100th cycle) and outstanding rate capability (967 mAh g{sup -1} at 5 C). Such a self-catalytic RATRP approach provides a way to synthesize nano-sized iron oxide-based anode materials industrially with preferable electrochemical performance and can also be applied in other polymer-related area.

  18. Tunable diode laser IR spectrometer for in situ measurements of the gas phase composition and particle size distribution of Titan's atmosphere

    NASA Technical Reports Server (NTRS)

    Webster, Christopher R.; Sander, Stanley P.; Beer, Reinhard; May, Randy D.; Knollenberg, Robert G.

    1990-01-01

    A new instrument, the Probe Infrared Laser Spectrometer (PIRLS), is described for in situ sensing of the gas composition and particle size distribution of Titan's atmosphere on the NASA/ESA Cassini mission. For gas composition measurements, several narrow-band (0.0001/cm) tunable lead-salt diode lasers operating near 80 K at selected mid-IR wavelengths are directed over a path length defined by a small reflector extending over the edge of the probe spacecraft platform; volume mixing ratios of 10 to the -9th should be measurable for several species of interest. A cloud-particle-size spectrometer using a diode laser source at 780 nm shares the optical path and deployed reflector; a combination of imaging and light scattering techniques is used to determine sizes of haze and cloud particles and their number density as a function of altitude.

  19. [Species composition and distribution characteristics of pelagic copepods in the Northern Sea of Fujian during withdraw of Zhe-Min coastal current].

    PubMed

    Wang, Yan-Guo; Lin, Jing-Hong; Wang, Chun-Guang; Lin, Mao

    2012-06-01

    Based on oceanographic survey data in April 2009 in the north central Taiwan Strait, ecological characteristics such as species composition, individual density, dominant species and distribution were analyzed. The results were compared with the same area survey in spring 2007 for discuss the annual variety. The result shows that 48 pelagic copepods species have been recognized, and most of them belongs to Calanodia. The higher species number occurs in southern and eastern area. The average density of pelagic copepoda was 231.96 ind x m(-3). As to the horizontal distribution, the coast and northern areas are higher than those of eastern and southern areas of the density of pelagic copepods which are dependent on the dominant species Calanus sinicus and Euchaeta plana. The community structure of pelagic copepoda was same to the other survey result, which shows low biodiversity index with remarkable dominant species. Owing to the Zhe-Min coastal current effect, the higher density distribution is different in 2007 and 2009. As to the ecological character, all the copepoda in this paper belong to warm-water, warm-temperature and tropic oceanic groups. Warm-water and tropic oceanic groups are the dominant groups of the pelagic copepods composition. When it comes to density, warm-temperature group is the dominant. The relationship of species number, diversity index and abundance with the environment were also discussed in this paper. The result showed that the pelagic copepoda species number and diversity would increase with the temperature and salty increase. PMID:22946163

  20. Fatigue crack initiation and multiplication of unnotched titanium matrix composites

    SciTech Connect

    Her, Y.C.; Wang, P.C.; Yang, J.M. [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering] [Univ. of California, Los Angeles, CA (United States). Dept. of Materials Science and Engineering

    1998-11-20

    Fatigue crack initiation and multiplication of the unnotched SCS-6 silicon carbide fiber-reinforced titanium matrix composites with different matrix and interfacial properties have been investigated experimentally and analytically. Ti-15V-3Al, Ti-6Al-4V, and Ti-22Al-23Nb were chosen as matrix materials. The initiation and propagation of each individual matrix crack as a function of fatigue cycles and applied stress levels were carefully monitored. The statistical distribution of crack growth rates in each composite has been constructed and analyzed. The evolution of normalized matrix crack density and stiffness reduction of these composites under fatigue loading also has been characterized. A modified shear-lag model, coupled with the strain-life equation and a fiber bridging model were used to predict the fatigue crack initiation life, matrix crack growth rate, normalized matrix crack density, and residual stiffness of the composites. The predicted fatigue properties correlated well with experimental results.

  1. Distribution of fish in seagrass, mangroves and coral reefs: life-stage dependent habitat use in Honduras.

    PubMed

    Jaxion-Harm, Jessica; Saunders, James; Speight, Martin R

    2012-06-01

    Many coral reef fish exhibit habitat partitioning throughout their lifetimes. Such patterns are evident in the Caribbean where research has been predominantly conducted in the Eastern region. This work addressed the paucity of data regarding Honduran reef fish distribution in three habitat types (seagrass, mangroves, and coral reefs), by surveying fish on the islands of Utila and Cayos Cochinos off the coast of Honduras (part of the Mesoamerican barrier reef). During July 2nd - Aug 27th 2007 and June 22nd - Aug 17th, 2008, visual surveys (SCUBA and snorkel) were performed in belt transects in different areas: eleven coral reef, six seagrass beds, and six mangroves sites. Juvenile densities and total habitat surface area were used to calculate nursery value of seagrass and mangroves. A total of 113 fish species from 32 families were found during underwater surveys. Multi-dimensional analyses revealed distinct clusters of fish communities in each habitat type by separating fish associated with seagrass beds, mangroves, and coral reefs. Coral reefs showed the highest mean fish species richness and were dominated by adult fish, while juvenile fish characterized seagrass beds and mangrove sites. Habitat use differed widely at the fish species level. Scarus iseri (Striped Parrotfish), the most abundant fish in this study, were found in all three habitat types, while Lutjanus apodus (Schoolmaster Snapper) juveniles were located primarily in mangroves before migrating to coral reefs. Many species used seagrass beds and mangroves as nurseries; however, the nursery value could not be generalized at the family level. Furthermore, for some fish species, nursery value varied between islands and sites. Our results suggest that connectivity of seagrass, mangrove, and coral reef sites at a species and site levels, should be taken into consideration when implementing policy and conservation practices. PMID:23894938

  2. Spin-Lattice Distribution MRI Maps Nigral Pathology in Progressive Supranuclear Palsy (PSP) during Life: A Pilot Study

    PubMed Central

    Hutchinson, Michael; Raff, Ulrich; Chaná, Pedro; Huete, Isidro

    2014-01-01

    An MRI biomarker for Parkinsonism has long been sought, but almost all attempts at conventional field strengths have proved unsatisfactory, since patients and controls are not separated. The exception is Spin-Lattice Distribution MRI (SLD-MRI), a technique which detects changes in the substantia nigra (SN) due to changes in the spin-lattice relaxation time, T1. This easily separates patients with Parkinson's disease (PD) from control subjects at 1.5 Tesla, suggesting that it may be sensitive to presymptomatic disease. SLD-MRI demonstrates a topography of signal change within the SN which is the same as the known topography of pathological change, where the lateral portions of the nucleus are more affected than the medial. In a further step towards its validation, we apply SLD-MRI to a disease control, Progressive Supranuclear Palsy (PSP), the most common of the atypical forms of Parkinsonism. In PSP the topography of pathological change in the SN is reversed. We therefore hypothesized that PSP would show a topography of SLD-MRI signal change in the SN that is the reverse of PD (i.e. the medial portion is more affected than the lateral). All 7 patients showed such a topography of MR signal, and all patients were separated from control subjects. Although this is a step toward validation of SLD-MRI with respect to sensitivity and disease specificity, nevertheless we stress that this is a pilot project only. Validation will only be possible when comparing larger cohorts of PSP, PD and control subjects. PMID:24489655

  3. Spin-lattice distribution MRI maps nigral pathology in progressive supranuclear palsy (PSP) during life: a pilot study.

    PubMed

    Hutchinson, Michael; Raff, Ulrich; Chaná, Pedro; Huete, Isidro

    2014-01-01

    An MRI biomarker for Parkinsonism has long been sought, but almost all attempts at conventional field strengths have proved unsatisfactory, since patients and controls are not separated. The exception is Spin-Lattice Distribution MRI (SLD-MRI), a technique which detects changes in the substantia nigra (SN) due to changes in the spin-lattice relaxation time, T1. This easily separates patients with Parkinson's disease (PD) from control subjects at 1.5 Tesla, suggesting that it may be sensitive to presymptomatic disease. SLD-MRI demonstrates a topography of signal change within the SN which is the same as the known topography of pathological change, where the lateral portions of the nucleus are more affected than the medial. In a further step towards its validation, we apply SLD-MRI to a disease control, Progressive Supranuclear Palsy (PSP), the most common of the atypical forms of Parkinsonism. In PSP the topography of pathological change in the SN is reversed. We therefore hypothesized that PSP would show a topography of SLD-MRI signal change in the SN that is the reverse of PD (i.e. the medial portion is more affected than the lateral). All 7 patients showed such a topography of MR signal, and all patients were separated from control subjects. Although this is a step toward validation of SLD-MRI with respect to sensitivity and disease specificity, nevertheless we stress that this is a pilot project only. Validation will only be possible when comparing larger cohorts of PSP, PD and control subjects. PMID:24489655

  4. The composition and distribution of the rejuvenated component across the Hawaiian plume: Hf-Nd-Sr-Pb isotope systematics of Kaula lavas and pyroxenite xenoliths

    NASA Astrophysics Data System (ADS)

    Bizimis, Michael; Salters, Vincent J. M.; Garcia, Michael O.; Norman, Marc D.

    2013-10-01

    Rejuvenated volcanism refers to the reemergence of volcanism after a hiatus of 0.5-2 Ma following the voluminous shield building stage of Hawaiian volcanoes. The composition of the rejuvenated source and its distribution relative to the center of the plume provide important constraints on the origin of rejuvenated volcanism. Near-contemporaneous lavas from the Kaula-Niihau-Kauai ridge and the North Arch volcanic field that are aligned approximately orthogonally to the plume track can constrain the lateral geochemical heterogeneity and distribution of the rejuvenated source across the volcanic chain. Nephelinites, phonolites and pyroxenite xenoliths from Kaula Island have radiogenic Hf, Nd and unradiogenic Sr isotope compositions consistent with a time-integrated depleted mantle source. The pyroxenites and nephelinites extend to the lowest 208Pb/204Pb reported in Hawaiian rocks. These data, along with new Pb isotope data from pyroxenites from the Salt Lake Crater (Oahu) redefine the composition of the depleted end-member of the Hawaiian rejuvenated source at 208Pb/204Pb=37.35±0.05, 206Pb/204Pb = 17.75±0.03, ?Nd = 9-10, ?Hf ˜16-17 and 87Sr/88Sr <0.70305. The revised isotope composition also suggests that this depleted component may contribute to LOA and KEA trend shield stage Hawaiian lavas, consistent with the rejuvenated source being part of the Hawaiian plume and not entrained upper mantle. The isotope systematics of rejuvenated magmas along the Kaula-Niihau-Kauai-North Arch transect are consistent with a larger proportion of the rejuvenated depleted component in the periphery of the plume track rather than along its axis.

  5. Application of Image And X-Ray Microtomography Technique To Quantify Filler Distribution In Thermoplastic-Natural Rubber Blend Composites

    SciTech Connect

    Ahmad, Sahrim; Rasid, Rozaidi; Mouad, A. T. [Faculty of Applied Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bandar Baru Bangi, 43000 Kajang (Malaysia); Aziz Mohamed, A.; Abdullah, Jaafar; Dahlan, M.; Mohamad, Mahathir; Jamro, Rafhayudi; Hamzah Harun, M. [Malaysian Nuclear Agency, Bangi, 43000 Kajang (Malaysia); Yazid, Hafizal [Faculty of Applied Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bandar Baru Bangi, 43000 Kajang (Malaysia); Hafizal Yazid, Faculty of Applied Science and Technology, Universiti Kebangsaan Malaysia (UKM), Bandar Baru Bangi, 43000 Kajang (Malaysia); Abdullah, W. Saffiey W.

    2010-01-05

    X-ray microtomography and ImageJ 1.39 u is used as a tool to quantify volume percentage of B{sub 4}C as fillers in thermoplastic-natural rubber blend composites. The use of percentage of area occupied by fillers as obtain from ImageJ from the microtomography sliced images enables the proposed technique to easily obtain the amount volume percentage of B{sub 4}C in the composite non-destructively. Comparison with other technique such as density measurement and chemical analysis proves the proposed technique as one of the promising approach.

  6. Three years in the coronal life of AB Dor. I. Plasma emission measure distributions and abundances at different activity levels

    E-print Network

    J. Sanz-Forcada; A. Maggio; G. Micela

    2003-07-04

    The young active star AB Dor (K1 IV-V) has been observed 16 times in the last three years with the XMM-Newton and Chandra observatories, totalling 650 ks of high-resolution X-ray spectra. The XMM/RGS observations with the highest and lowest average emission levels have been selected to study the coronal properties of AB Dor in two different activity levels. We compare the results based on the XMM data with those obtained from a higher resolution Chandra/HETG spectrum, using the same line-based analysis technique. We have reconstructed the plasma Emission Measure Distribution vs. temperature (EMD) in the range log T(K) ~ 6.1-7.6, and we have determined the coronal abundances of AB Dor, obtaining consistent results between the two instruments.The overall shape of the EMD is also consistent with the one previously inferred from EUVE data. The EMD shows a steep increase up to the peak at log T (K) ~ 6.9 and a substantial amount of plasma in the range log T (K) ~ 6.9-7.3. The coronal abundances show a clear trend of increasing depletion with respect to solar photospheric values, for elements with increasing First Ionization Potential (FIP), down to the Fe value ([Fe/H]=-0.57), followed by a more gradual recovery of the photospheric values for elements with higher FIP. He-like triplets and Fe XXI and Fe XXII lines ratios indicate electron densities log ne~10.8 cm^-3 at log T(K) ~ 6.3 and log ne ~ 12.5 at log T(K) ~ 7, implying plasma pressures steeply increasing with temperature. These results are interpreted in the framework of a corona composed of different families of magnetic loop structures, shorter than the stellar radius and in isobaric conditions, having pressures increasing with the maximum plasma temperature, and which occupy a small fraction (f ~ 10^-4 - 10^-6) of the stellar surface.

  7. Advanced composites for windmills

    NASA Astrophysics Data System (ADS)

    Bourquardez, G.

    A development status assessment is conducted for advanced composite construction techniques for windmill blade structures which, as in the case of composite helicopter rotors, promise greater reliability, longer service life, superior performance, and lower costs. Composites in wind turbine applications must bear aerodynamic, inertial and gravitational loads in complex interaction cycles. Attention is given to large Darrieus-type vertical axis windmills, to which composite construction methods may offer highly effective pitch-control mechanisms, especially in the 'umbrella' configuration.

  8. Distribution center and retail conditions affect the sensory and compositional quality of bulk and packaged slicing cucumbers

    Microsoft Academic Search

    M. Cecilia N. Nunes; Jean-Pierre Emond; Sharon Dea; Yavuz Yagiz

    2011-01-01

    During distribution and retail display, fruits and vegetables are often exposed to undesirable temperature and humidity conditions which often result in increased waste due to weight loss and objectionable appearance. Unwaxed fresh-market slicing cucumbers (cv. Calypso) were harvested from a commercial operation and shipped to a distribution center (DC) in Florida. At the DC, 2 d after harvest, cucumbers were

  9. Ventilation distribution in rats: Part I - The effect of gas composition as measured with electrical impedance tomography

    PubMed Central

    2012-01-01

    Abstract The measurement of ventilation distribution is currently performed using inhaled tracer gases for multiple breath inhalation studies or imaging techniques to quantify spatial gas distribution. Most tracer gases used for these studies have properties different from that of air. The effect of gas density on regional ventilation distribution has not been studied. This study aimed to measure the effect of gas density on regional ventilation distribution. Methods Ventilation distribution was measured in seven rats using electrical impedance tomography (EIT) in supine, prone, left and right lateral positions while being mechanically ventilated with either air, heliox (30% oxygen, 70% helium) or sulfur hexafluoride (20% SF6, 20% oxygen, 60% air). The effect of gas density on regional ventilation distribution was assessed. Results Gas density did not impact on regional ventilation distribution. The non-dependent lung was better ventilated in all four body positions. Gas density had no further impact on regional filling characteristics. The filling characteristics followed an anatomical pattern with the anterior and left lung showing a greater impedance change during the initial phase of the inspiration. Conclusion It was shown that gas density did not impact on convection dependent ventilation distribution in rats measured with EIT. PMID:22947026

  10. An Investigation of Aerosol Measurements from the Halogen Occultation Experiment: Validation, Size Distributions, Composition, and Relation to Other Chemical Species

    NASA Technical Reports Server (NTRS)

    Deshler, Terry; Hervig, Mark E.

    1998-01-01

    The efforts envisioned within the original proposal (accepted February 1994) and the extension of this proposal (accepted February 1997) included measurement validations, the retrieval of aerosol size distributions and distribution moments, aerosol correction studies, and investigations of polar stratospheric clouds. A majority of the results from this grant have been published. The principal results from this grant are discussed.

  11. Species composition, distribution and abundance of macrozooplankton in the intake and discharge areas after construction and operation of the Cedar Bayou electric power station

    E-print Network

    Jones, Timothy Lee

    1975-01-01

    SPECIES COMPOSITION% DISTRIBUTION AND ABUNDANCE OF MACROZOOPLANKTON IN THE INTAKE AND DISCHARGE AREAS AFTER CONSTRUCTION AND OPERATION OF THE CEDAR BAYOU ELECTRIC POWER STATION A Thesis by TIMOTHY LEE JONES Submitted to the Graduate College... AND DISCHARGE AREAS AFTER CONSTRUCTION AND OPERATION OF THE CEDAR BAYOU ELECTRIC POWER STATION A Thesis by TI'MOTHY LEE JONES Approved as to syt1e and content by: Q L~ /I airman o Co mitte Head of Department Mem er Mem er May 1975 ABSTRACT Species...

  12. Measurement of Dijet Angular Distributions and Search for Quark Compositeness in pp Collisions at $sqrt{s} = 7$ TeV

    SciTech Connect

    Khachatryan, Vardan [Yerevan Physics Inst. (Armenia); et al.

    2011-05-01

    Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at s? = 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 inverse picobarns. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of Lambda = 5.6 TeV is obtained at the 95% confidence level.

  13. Application of FORC distributions to the study of magnetic interactions in ferrites of composition Ba1-xLaFe12-xCoxO19

    NASA Astrophysics Data System (ADS)

    Oliva, M. I.; Bercoff, P. G.; Bertorello, H. R.

    Magnetic interactions in hexaferrite samples of Ba1-xLaFe12-xCoxO19 composition were studied. The precursor powders—barium carbonate (BaCO3), lanthanum oxide (La 2O 3), hematite (Fe 2O 3) and cobalt acetate—were milled for 100 h in air atmosphere and heat-treated for 1 h at 1000C. The structural characterization was performed by X-ray diffraction. The FORC distributions show a single peak at high switching fields, indicating that the substituted systems are formed by weakly interacting particles. La excess induces the decoupling of the particles.

  14. The effects of solid rocket motor effluents on selected surfaces and solid particle size, distribution, and composition for simulated shuttle booster separation motors

    NASA Technical Reports Server (NTRS)

    Jex, D. W.; Linton, R. C.; Russell, W. M.; Trenkle, J. J.; Wilkes, D. R.

    1976-01-01

    A series of three tests was conducted using solid rocket propellants to determine the effects a solid rocket plume would have on thermal protective surfaces (TPS). The surfaces tested were those which are baselined for the shuttle vehicle. The propellants used were to simulate the separation solid rocket motors (SSRM) that separate the solid rocket boosters (SRB) from the shuttle launch vehicle. Data cover: (1) the optical effects of the plume environment on spacecraft related surfaces, and (2) the solid particle size, distribution, and composition at TPS sample locations.

  15. Comparison of lipid content and fatty acid composition and their distribution within seeds of 5 small grain species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Barley, oats, rice, sorghum, and wheat, each with two genotypes, were sequentially abraded by an electric seed scarifier. The pearling fines (PF) and pearled kernels (PK) at each cycle were analyzed for lipid (mostly nonpolar) content and fatty acid (FA)composition. The oil content in whole or deh...

  16. Concentration distribution of elements and variation in phase composition during solid-solution decomposition in Fe-Cr-Co alloy

    Microsoft Academic Search

    A. S. Perminov; S. O. Maslennikov; A. S. Lileev; E. A. Shuvaeva; V. L. Stolyarov; D. G. Zhukov

    2010-01-01

    In the present work, we analyze the changes in chemical and phase composition in the decomposition of metastable supercooled hightemperature ? solid solution in the alloy Fe + 31 wt % Cr + 23 wt % Co. Permanent magnets based on Fe-Cr-Co alloys are still widely used in industry, although they cannot match the properties of the latest alloys of

  17. EVALUATION OF A UAV COMPOSITE WING SPAR REPAIR USING AN EMBEDDED OPTICAL FIBER RAYLEIGH BACK-SCATTERING DISTRIBUTED STRAIN SENSING

    E-print Network

    Paris-Sud XI, Université de

    EVALUATION OF A UAV COMPOSITE WING SPAR REPAIR USING AN EMBEDDED OPTICAL FIBER RAYLEIGH BACK Branch, Tel-Aviv Israel ikressel@iai.co.il ABSTRACT A representing damaged UAV wing spar cap was repaired requirements for UAVs, where the substantiation of structural bonded joint can be based on: "repeatable

  18. Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

    Microsoft Academic Search

    Marcela C. Moscol Olivera; Antoine M. Cleef

    2009-01-01

    Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 in were examined along two altitudinal transects crossing the Upper Forest Line (UFL). The phytosociological subdivision using TWINSPAN revealed two communities for Guandera

  19. Production and distribution of melt in domainal migmatite deciphered by micro-mapping the local effective bulk compositions

    NASA Astrophysics Data System (ADS)

    Lanari, Pierre; Riel, Nicolas; Engi, Martin

    2015-04-01

    Migmatites are fantastic targets to study the evolution of melt compositions, because they represent levels in the crust where partial melting has occurred. However, migmatites commonly have a complex history because they are the products of different transformation processes, such as (i) melt producing reactions, (ii) melt migration, and (iii) retrograde reactions. Evidence of such processes is preserved in the minerals and microstructures of rocks that outcrop in deeply exhumed orogens. The complexity of migmatites is due to their chemical and textural heterogeneity visible in different domains with various mineral assemblages. Partial melting of pelites involves reactions that are predictable using thermodynamic models. However, a forward modeling approach based on rock-specific equilibrium phase diagrams (P-T sections) requires the knowledge of local bulk composition for each equilibrium assemblage. This study demonstrates that suitable local effective bulk (LEB) compositions can be derived by means of standardized microprobe X-ray images, using the program XMAPTOOLS. For chemically heterogeneous samples, such as domanial migmatites, these LEB compositions allow the stable mineral assemblages to be modeled for each domain and to obtain reliable P-T estimates. A metapelite sample studied in detail derived from a metasedimentary xenolith in the Marcabeli pluton, El Oro Complex, Ecuador. This sample shows complex mineral patterns due to local melt redistribution (at mm to cm-scale), involving major changes that affected the local chemical composition observed today. Four domains are identified: A residuum domain made of cordierite + biotite + plagioclase + spinel, which is a metamorphic assemblage stable at P-Tmax conditions of 750 ± 50°C and 2 ± 1 kbar. In the leucosome (plagioclase + Kspar + quartz + biotite + orthopyroxene) three sub-domains show different mineral assemblages. Domain-specific equilibrium assemblages in the P-T sections demonstrate that these three assemblages reflect three interconnected melt-rich domains, each with different melt fractions (from 29 to 93 vol-%), yet all coexisted at equilibrium near P-Tmax conditions.

  20. Measurement of dijet angular distributions at sqrt{s}=1.96TeV and searches for quark compositeness and extra spatial dimensions

    SciTech Connect

    Collaboration, D0

    2009-06-01

    We present the first measurement of dijet angular distributions in p{bar p} collisions at {radical}s = 1.96 TeV at the Fermilab Tevatron Collider. The measurement is based on a dataset corresponding to an integrated luminosity of 0.7 fb{sup -1} collected with the D0 detector. Dijet angular distributions have been measured over a range of dijet masses, from 0.25 TeV to above 1.1 TeV. The data are in good agreement with the predictions of perturbative QCD and are used to constrain new physics models including quark compositeness, large extra dimensions, and TeV{sup -1} scale extra dimensions. For all models considered, we set the most stringent direct limits to date.

  1. DISTRIBUTION AND COMPOSITION OF DISSOLVED AND PARTICULATE ORGANIC CARBON IN NORTHERN SAN FRANCISCO BAY DURING LOW FRESHWATER FLOW CONDITIONS

    EPA Science Inventory

    The distribution of organic matter was studied in northern San Francisco Bay monthly through spring and summer 1996 along the salinity gradient from the Sacramento River to Central Bay. Dissolved constituents included monosaccharides (MONO), total carbohydrates (TCHO), dissolved ...

  2. Distribution and life history of the planktonic copepod, Eucalanus californicus, in the northwestern Pacific: Mechanisms for population maintenance within a high primary production area

    NASA Astrophysics Data System (ADS)

    Shimode, Shinji; Takahashi, Kazutaka; Shimizu, Yugo; Nonomura, Takumi; Tsuda, Atsushi

    2012-04-01

    We investigated the geographical and vertical distribution of the copepodid stages of Eucalanus californicus in the northwestern (NW) Pacific Ocean, and compared life history characteristics against the northeastern (NE) population of the species and the neighboring subarctic sister species, Eucalanus bungii. In the NW Pacific, multi-layered zooplankton samples were collected between 15°N and 49°N. High abundances (>1000 inds. m-2) of E. californicus were restricted to an area around 33°N, whereas E. bungii was highly abundant between 36°N and 49°N. The occurrence of E. californicus in the surface layer was associated with seasonal spring ontogenetic vertical migration (OVM), as suggested by previous studies in the NE Pacific. Gonadal analysis of adult females showed that surface reproduction occurs during the spring in the slope water area, which is a region on the continental slope north of the Kuroshio axis, and within the Kuroshio-Oyashio Transition Area (TA). The seasonal OVM strategy of E. californicus in the NW Pacific is characterized by (1) shorter periods of surface reproduction and growth and (2) deep C5 stage dormancy (500-2000 m). The former is an adaptive response to relatively high water temperatures and short bloom periods in the TA and slope water area. The latter strategy of deep dormancy is considered to be an adaptation to avoid drift caused by a local oceanic feature of deeper westward (>1000 m) recirculation currents, thus retaining the population within the high primary production zones of the TA and slope water area.

  3. Boundary Layer Aerosol Composition over Sierra Nevada Mountains using 9.11- and 10.59-micron CW Lidars and Modeled Backscatter from Size Distribution Data

    NASA Technical Reports Server (NTRS)

    Cutten, D. R.; Jarzembski, M. A.; Srivastava, V.; Pueschel, R. F.; Howard, S. D.; McCaul, E. W., Jr.

    2003-01-01

    An inversion technique has been developed to determine volume fractions of an atmospheric aerosol composed primarily of ammonium sulfate and ammonium nitrate and water combined with fixed concentration of elemental and organic carbon. It is based on measured aerosol backscatter obtained with 9.11 - and 10.59-micron wavelength continuous wave CO2 lidars and modeled backscatter from aerosol size distribution data. The technique is demonstrated during a flight of the NASA DC-8 aircraft over the Sierra Nevada Mountain Range, California on 19 September, 1995. Volume fraction of each component and effective complex refractive index of the composite particle were determined assuming an internally mixed composite aerosol model. The volume fractions were also used to re-compute aerosol backscatter, providing good agreement with the lidar-measured data. The robustness of the technique for determining volume fractions was extended with a comparison of calculated 2.1,-micron backscatter from size distribution data with the measured lidar data converted to 2.1,-micron backscatter using an earlier derived algorithm, verifying the algorithm as well as the backscatter calculations.

  4. A new technique to measure cosmic ray energy and composition via (2+1)d lateral distribution function fits to surface detector array data

    SciTech Connect

    Chou, Aaron S.; /Fermilab; Pernas, Maximo David Ave; Yamamoto, Tokonatsu; /KICP, Chicago

    2005-08-01

    The concept of a one-dimensional lateral distribution function is extended to a set of (2+1)d functions which describe the spatial and temporal distributions of the muonic and electromagnetic components of extended air showers. By design, these functions incorporate the curvature and time structure of the shower front as well as the asymmetries in particle density and in time structure expected in inclined showers. These observables are sensitive to the mass of the primary cosmic ray and to the details of the hadronic interactions inducing the air shower. The (2+1)d functions smoothly interpolate between the values of X{sub max} and muon flux predicted by various simulations performed with different assumptions of primary composition and interaction model. A maximum likelihood fit to surface detector array data can then give simultaneous event-by-event measurements of the shower energy, X{sub max}, and the muon content, from which the primary composition may subsequently be inferred. The methods outlined are applicable to a large number of existing and future shower detector arrays covering a range of energies.

  5. Spatial distribution and floristic composition of trees and lianas in different forest types of an Amazonian rainforest

    Microsoft Academic Search

    Manuel J. Macía

    2011-01-01

    A quantitative inventory of trees and lianas was conducted (1) to compare floristic composition, diversity and stem density\\u000a variation between three different forest types (tierra firme, floodplain and swamp), and (2) to analyse the relationships\\u000a between floristic similarity and forest structure in two regions ~60 km apart in Yasuní National Park, Amazonian Ecuador.\\u000a A total of 1,087 species with a diameter

  6. ICAF Symposium Montral, 13 June 2011 FATIGUE LIFE ASSESSMENT

    E-print Network

    Texas at Arlington, University of

    assessment of useful life for composite aircraft fatigue-critical, flight-critical components and structure advances in the technologies which could enable accurate assessment of useful life for composite aircraft26th ICAF Symposium ­ Montréal, 1­3 June 2011 FATIGUE LIFE ASSESSMENT FOR COMPOSITE STRUCTURE

  7. Impact of the LDL subfraction phenotype on Lp-PLA2 distribution, LDL modification and HDL composition in type 2 diabetes

    PubMed Central

    2013-01-01

    Background Qualitative alterations of lipoproteins underlie the high incidence of atherosclerosis in diabetes. The objective of this study was to assess the impact of low-density lipoprotein (LDL) subfraction phenotype on the qualitative characteristics of LDL and high-density lipoprotein (HDL) in patients with type 2 diabetes. Methods One hundred twenty two patients with type 2 diabetes in poor glycemic control and 54 healthy subjects were included in the study. Patients were classified according to their LDL subfraction phenotype. Seventy-seven patients presented phenotype A whereas 45 had phenotype B. All control subjects showed phenotype A. Several forms of modified LDL, HDL composition and the activity and distribution of lipoprotein-associated phospholipase A2 (Lp-PLA2) were analyzed. Results Oxidized LDL, glycated LDL and electronegative LDL were increased in both groups of patients compared with the control group. Patients with phenotype B had increased oxidized LDL and glycated LDL concentration than patients with phenotype A. HDL composition was abnormal in patients with diabetes, being these abnormalities more marked in patients with phenotype B. Total Lp-PLA2 activity was higher in phenotype B than in phenotype A or in control subjects. The distribution of Lp-PLA2 between HDL and apoB-containing lipoproteins differed in patients with phenotype A and phenotype B, with higher activity associated to apoB-containing lipoproteins in the latter. Conclusions The presence of LDL subfraction phenotype B is associated with increased oxidized LDL, glycated LDL and Lp-PLA2 activity associated to apoB-containing lipoproteins, as well as with abnormal HDL composition. PMID:23915379

  8. The Use of Soft X-ray Spectromicroscopy to Investigate the Distribution and Composition of Organic Matter in a Diatom Frustule and a Biomimetic Analog

    SciTech Connect

    Abramson, L.; Wirick, S; Lee, C; Jacobsen, C; Brandes, J

    2009-01-01

    Diatoms play a significant role in the global carbon cycle through their role in biogenic silica production and the transport of organic matter to the seafloor. Recent work has shown that silicified diatom frustules contain a significant amount of organic matter, and that the proportion of diatom-bound organic matter increases with depth in the water column and sediments. Here, we investigate the association between organic matter and the mineral phase. We used a combination of scanning transmission X-ray microscopy (STXM) and carbon X-ray absorption near-edge structure (XANES) spectroscopy to characterize the distribution and composition of organic matter in frustules of the diatom Cylindrotheca closterium and a biomimetic silica gel. To our knowledge, this study represents the first successful attempt to simultaneously image and obtain chemical information about the organic matter within a diatom frustule using X-ray spectromicroscopy near the carbon edge. Organic carbon, most likely protein, was distributed throughout the frustules and was not removed by harsh chemical treatment. The physical structure of the frustules appeared to be related to the chemical composition of this organic matter, with aromatic or unsaturated carbon being concentrated in the most intricately patterned regions of the frustule. A similar physical and chemical structure was observed in a biomimetic silica gel precipitated spontaneously with polylysine. These results are consistent with the theory that organic constituents of diatom frustules direct silica precipitation and become incorporated within the silica matrix as it forms. The relationship between organic matter composition and silica morphology, the failure of harsh chemical treatments to remove this organic matter, and the spontaneous nature of the co-precipitation of silica and organic matter indicate some chemical interaction between the siliceous and organic components of diatom frustules. Frustule-bound organic matter should therefore be protected from decomposition in the water column or diagenetic alteration in sediments unless the frustule dissolves.

  9. Influence of processing route on electrical and thermal conductivity of Al\\/SiC composites with bimodal particle distribution

    Microsoft Academic Search

    L. Weber; G. Sinicco; J. M. Molina

    2010-01-01

    Al\\/SiC composites with volume fractions of SiC between 0.55 and 0.71 were made from identical tapped and vibrated powder preforms\\u000a by squeeze casting (SC) and by two different setups for gas pressure infiltration (GPI), one that allows short (1–2 min) liquid\\u000a metal\\/ceramic contact time (fast GPI) and the other that operates with rather long contact time, i.e., 10–15 min, (slow GPI).\\u000a Increased

  10. Production Mechanism, Number Concentration, Size Distribution, Chemical Composition, and Optical Properties of Sea Spray Aerosols Workshop, Summer 2012

    SciTech Connect

    Meskhidze, Nicholas [NCSU] [NCSU

    2013-10-21

    The objective of this workshop was to address the most urgent open science questions for improved quantification of sea spray aerosol-radiation-climate interactions. Sea spray emission and its influence on global climate remains one of the most uncertain components of the aerosol-radiation-climate problem, but has received less attention than other aerosol processes (e.g. production of terrestrial secondary organic aerosols). Thus, the special emphasis was placed on the production flux of sea spray aerosol particles, their number concentration and chemical composition and properties.

  11. DISTRIBUTION AND COMPOSITION OF DISSOLVED AND PARTICULATE ORGANIC CARBON IN NORTHERN SAN FRANCISCO BAY DURING LOW FRESHWATER FLOW CONDITIONS

    EPA Science Inventory

    The distribution of dissolved and particulate organic matter was studied in northern San Francisco Bay on seven dates during declining flow conditions from April to October 1996. Measurements were made at 3 to 11 stations (usually 8) along the salinity gradient from the Sacrament...

  12. Viscosity and radial distribution function in PbxSe(1-x) melts for stoechiometric and peritectic compositions

    E-print Network

    Paris-Sud XI, Université de

    L-529 Viscosity and radial distribution function in PbxSe(1-x) melts for stoechiometric by lead atoms sur- rounded by Se atoms are considered. Kinematic viscosity data are compared a molecular structure in the liquid state rather than a chain-structure [1]. Viscosity is very sensitive

  13. Distribution center and retail conditions affect the sensory and compositional quality of bulk and packaged slicing cucumbers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During distribution and retail display, fruits and vegetables are often exposed to undesirable temperature and humidity conditions which often result in increased waste due to weight loss and objectionable appearance. Unwaxed fresh-market slicing cucumbers (cv. Calypso) were harvested from a commerc...

  14. In-Situ X-Ray Microscopy of Phase and Composition Distributions in Metal Alloys During Solidification

    NASA Technical Reports Server (NTRS)

    Kaukler, William F.; Curreri, Peter A.

    1999-01-01

    This research applies a state of the art X-ray Transmission Microscope, to image the solidification of metallic or semiconductor alloys in real-time. By employing a hard x-ray source with sub-micron dimensions, resolutions of up to 3 gm can be obtained with magnifications of over 800 X. Specimen growth conditions were optimized and the best imaging technologies applied to maintain x-ray image resolution, contrast and sensitivity. In addition, a special furnace design is required to permit controlled growth conditions and still offer maximum resolution and image contrast. We have successfully imaged in real-time: interfacial morphologies, phase growth, coalescence, incorporation of phases into the growing interface, and the solute boundary layer in the liquid at the solid-liquid inter-face. We have also measured true local growth rates and can evaluate segregation structures in the solid; a form of in-situ metallography. Composition gradients within the specimen cause vafiations in absorption of the flux such that the final image represents a spatial integral of composition (or thickness). During this study, the growth of secondary phase fibers and lameilae from eutectic and monotectic alloys have been imaged during solidification, in real-time, for the first time in bulk metal alloys. Keywords: x-ray, microscope, solidification, microfocus, real-time, microstructure

  15. Beam attenuation, scattering and backscattering of marine particles in relation to particle size distribution and composition in Hudson Bay (Canada)

    NASA Astrophysics Data System (ADS)

    Xi, Hongyan; Larouche, Pierre; Michel, Christine; Tang, Shilin

    2015-05-01

    This study investigated the relationships between the concentration of biogeochemical parameters and particulate beam attenuation (cp), scattering (bp), and backscattering (bbp) in Hudson Bay. Results showed that most of the variability resulted from the presence of a deep chlorophyll maximum. cp, bp, and bbp were all adequate proxies to estimate total suspended matter (TSM) but were mostly sensitive to particulate inorganic matter (PIM) in the surface layer, and particulate organic matter (POM) at the chlorophyll maximum depth. The backscattering ratio b˜bp varied in the range of 0.005-0.05 and was inversely related to the POM : TSM ratio. According to the Twardowski et al. (2001) model, the PSD slope ? well represented b˜bp and bulk refractive index n¯p in relation to particulate composition. For inorganic particulate dominated waters, both b˜bp and n¯p had a larger range and a higher mean value than at organic particulate dominated waters. This knowledge on the optical properties related to the PSD and particulate composition provides valuable information for further investigation and broadens our understanding of ocean optics in high latitude waters leading to potential improvements of regional scale remote sensing algorithms.

  16. Isotopic composition and concentration of Pb in suspended particulate matter of the Irish Sea reveals distribution and sources.

    PubMed

    Charlesworth, M E; Chenery, S; Mellor, A; Service, M

    2006-01-01

    The isotopic composition and concentration of Pb was measured in suspended particulate matter of the Irish Sea. Aerosol, surficial and pre-industrial sediment was also analysed to provide information on sources terms. Concentrations of Pb in suspended sediments were lower than previously reported which presumably reflects the international effort to reduce Pb inputs to the environment. Lead concentrations were highest in Liverpool Bay and lowest in the western Irish Sea. A significant negative relationship between Pb and salinity suggests that present inputs and the resuspension of relict lead associated with particles in areas significantly affected by freshwater discharges are the predominant sources of Pb to the Irish Sea. The isotopic composition of Pb in the stratified region of the western Irish Sea demonstrates that atmospheric sources are also significant to this region, which is consistent with current knowledge on the hydrography. Pb isotopic ratios show that water entering the Irish Sea through St George's Channel is significantly influenced by anthropogenic inputs prior to additional contamination by direct inputs to the Irish Sea. PMID:16194553

  17. Local geological dust in the area of Rome (Italy): linking mineral composition, size distribution and optical properties to radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Pietrodangelo, Adriana; Salzano, Roberto; Bassani, Cristiana; Pareti, Salvatore; Perrino, Cinzia

    2015-04-01

    Airborne mineral dust plays a key role in the energy balance of the Earth - atmosphere coupled system. The microphysical and optical properties of dust drive the direct radiative effects and are in turn influenced by the dust mineralogical composition. The latter varies largely, depending on the geology of the source region. Knowledge gaps still exist about relationships between the scattering and absorption of solar and terrestrial radiation by mineral dust and its mineralogical, size distribution and particle morphology features; this also affects the reliability of radiative transfer (RT) modelling estimates (Hansell et al., 2011). In this study, these relationships were investigated focusing on the crustal suspended PM10 dust, sourced from outcropping rocks of the local geological domains around Rome (Latium, Italy). The mineral composition variability of the Latium rocks ranges from the silicate-dominated (volcanics domain) to the calcite-dominated (travertine), through lithological materials composed in different proportions by silicates, silica and calcite, mainly (limestone series, siliciclastic series) (Cosentino et al., 2009). This peculiarity of the Latium region was thus exploited to investigate the behavior of the size distribution, optical properties and radiative transfer at BOA (Bottom Of Atmosphere) of the suspended dust PM10 fraction with the variability of mineral composition. Elemental source profiles of the same dust samples were previously determined (Pietrodangelo et al., 2013). A multi-faceted analysis was performed, and outcomes from the following approaches were merged: individual-particle scanning electron microscopy combined with X-ray energy-dispersive microanalysis (SEM XEDS), bulk mineralogical analysis by X-ray diffraction (XRD), size distribution fit of the individual-particle data set and modelling of the dust optical and radiative properties. To this aim, the 6SV atmospheric radiative transfer code (Kotchenova et al., 2008; Vermote et al., 1997) was employed, which computes aerosol optical properties (single-scattering albedo, asymmetry parameter, extinction coefficient, scattering coefficient, phase function) by the Mie Theory, and simulates the downward flux at BOA (FdBOA) by solving the radiative transfer equation. Conditions of dryness and of spherical particle shape were applied to all parts of this work. The size distribution fitting to the log-normal function appears unimodal, both for the volcanics and travertine domains, the first showing coarser mode than the latter. Volume distributions of quartz, feldspar, kaolinite and calcite fall in the coarse fraction, showing maximum around 5µm (aerodynamic diameter); differences in the curve height suggest particle density variety among mineral species. The single-scattering albedo highlights the weak absorption of travertine, with respect to volcanics, along the visible and Near-InfraRed (NIR) spectral domain. The asymmetry parameter indicates that the volcanics dust appears composed by particles with highly forward scattering, mainly in the Near-InfraRed (NIR) spectral domain, while the travertine shows more isotropic particles. Finally, both volcanics and travertine dusts leave the direct component of FdBOA unchanged, while the diffuse component depends strongly on the mineral composition. Hansell, R.A., et al. (2011), Atmos. Chem. Phys. Cosentino, D., et al. (2009), Quaternary Research Pietrodangelo, A., et al. (2013), Atmos. Env. Kotchenova, S.Y., et al. (2008), Appl. Optics Vermote, E.F., et al. (1997), IEEE Trans. Geosci. Remote Sens.

  18. Interplay between carotenoids, hemoproteins and the "life band" origin studied in live Rhodotorula mucilaginosa cells by means of Raman microimaging.

    PubMed

    Pacia, Marta Z; Turnau, Katarzyna; Baranska, Malgorzata; Kaczor, Agnieszka

    2015-03-21

    Raman microimaging of live Rhodotorula mucilaginosa cells, cultured under aerobic and anaerobic conditions, showed striking differences in the composition and distribution of cell components. The analysis of these differences and recovery of oxidative phosphorylation upon environmental changes enabled the interrelation of carotenoids, hemoproteins and the unknown species considered as the "Raman signature of life". PMID:25654139

  19. A unique hollow Li3VO4/carbon nanotube composite anode for high rate long-life lithium-ion batteries.

    PubMed

    Li, Qidong; Sheng, Jinzhi; Wei, Qiulong; An, Qinyou; Wei, Xiujuan; Zhang, Pengfei; Mai, Liqiang

    2014-10-01

    A unique hollow Li3VO4/CNT composite is synthesized via a facile method as an anode material in lithium batteries. Our work opens up the way for a promising material with high rate capability and good cycling stability due to its efficient Li(+) diffusion and relatively high structure stability. PMID:25155363

  20. Faunal breaks and species composition of Indo-Pacific corals: the role of plate tectonics, environment and habitat distribution

    PubMed Central

    Keith, S. A.; Baird, A. H.; Hughes, T. P.; Madin, J. S.; Connolly, S. R.

    2013-01-01

    Species richness gradients are ubiquitous in nature, but the mechanisms that generate and maintain these patterns at macroecological scales remain unresolved. We use a new approach that focuses on overlapping geographical ranges of species to reveal that Indo-Pacific corals are assembled within 11 distinct faunal provinces. Province limits are characterized by co-occurrence of multiple species range boundaries. Unexpectedly, these faunal breaks are poorly predicted by contemporary environmental conditions and the present-day distribution of habitat. Instead, faunal breaks show striking concordance with geological features (tectonic plates and mantle plume tracks). The depth range over which a species occurs, its larval development rate and genus age are important determinants of the likelihood that species will straddle faunal breaks. Our findings indicate that historical processes, habitat heterogeneity and species colonization ability account for more of the present-day biogeographical patterns of corals than explanations based on the contemporary distribution of reefs or environmental conditions. PMID:23698011

  1. Faunal breaks and species composition of Indo-Pacific corals: the role of plate tectonics, environment and habitat distribution.

    PubMed

    Keith, S A; Baird, A H; Hughes, T P; Madin, J S; Connolly, S R

    2013-07-22

    Species richness gradients are ubiquitous in nature, but the mechanisms that generate and maintain these patterns at macroecological scales remain unresolved. We use a new approach that focuses on overlapping geographical ranges of species to reveal that Indo-Pacific corals are assembled within 11 distinct faunal provinces. Province limits are characterized by co-occurrence of multiple species range boundaries. Unexpectedly, these faunal breaks are poorly predicted by contemporary environmental conditions and the present-day distribution of habitat. Instead, faunal breaks show striking concordance with geological features (tectonic plates and mantle plume tracks). The depth range over which a species occurs, its larval development rate and genus age are important determinants of the likelihood that species will straddle faunal breaks. Our findings indicate that historical processes, habitat heterogeneity and species colonization ability account for more of the present-day biogeographical patterns of corals than explanations based on the contemporary distribution of reefs or environmental conditions. PMID:23698011

  2. Does smoking have any effect on urinary stone composition and the distribution of trace elements in urine and stones?

    Microsoft Academic Search

    Marcin S?ojewski; Bogus?aw Czerny; Krzysztof Safranow; Marek Dro?dzik; Andrzej Pawlik; Katarzyna Jakubowska; Maria Olszewska; Adam Go??b; El?bieta Byra; Dariusz Chlubek; Andrzej Sikorski

    2009-01-01

    The role of particular elements in lithogenesis is still unclear and debated. Probably some of them may promote or conversely\\u000a inhibit crystal nucleation of organic or mineral species. A few epidemiological data link smoking with the risk of calcium\\u000a stones. The aim of this hospital-based study was to evaluate the distribution of trace elements in urine and urinary stones,\\u000a and

  3. Geographic distribution and genotypic composition of invasive hybrid watermilfoil ( Myriophyllum spicatum  ×  M. sibiricum ) populations in North America

    Microsoft Academic Search

    M. L. Moody; D. H. Les

    2007-01-01

    The recent recognition of invasive hybrid watermilfoil (Myriophyllum\\u000a spicatum × M. sibiricum) in North America has necessitated a more thorough evaluation of its overall distribution and occurrence in natural populations.\\u000a A comprehensive survey of watermilfoil populations was conducted in five Minnesota lakes, three of which were suspected a\\u000a priori to contain hybrid watermilfoil. DNA sequence data verified that hybrid plants between the

  4. Hematite in Valles Marineris: Context, Composition, Distribution, Morphology, Physical Properties, and Comparison to Other Mars Hematite Deposits

    NASA Astrophysics Data System (ADS)

    Knudson, A. T.; Christensen, P. R.

    2004-12-01

    Gray, crystalline hematite deposits have been identified by data from MGS TES at three areas on Mars: Meridiani Planum, Aram Chaos, and Valles Marineris. Remote sensing studies of the deposits at Meridiani Planum and Aram Chaos indicate that hematite occurs in relatively large, coherent, in-place stratigraphic units. In situ studies at the Meridiani Planum site by the MER Opportunity have revealed that the hematite is likely carried in spheroidal concretions that form lag deposits as they weather out of in-situ sedimentary layered deposits. The hematite occurrences in Valles Marineris are small, 5 - 35 km in diameter, and are discontinuous throughout the canyon system. In this study THEMIS, MOC, MOLA and TES data are used to investigate the geomorphology, composition, and thermophysical characteristics of hematite bearing deposits throughout the canyon system and compare them to the other hematite deposits on Mars. Hematite bearing deposits in Valles Marineris span an total elevation range of 5600m. Preliminary evaluation indicates no clear correlation of with latitude or longitude. In Ophir and Candor Chasmata, hematite is associated with relatively dark materials near or within interior layered deposits and may represent in-place units or erosional remnants. Deconvolution of TES spectra from Candor Chasma show hematite abundances from 5 to 12%. Associated materials exhibit compositions similar to TES Surface Type II, which has been described as a basaltic andesite or weathered basalt. In Capri Chasma hematite signatures generally correlate with layered units, which lie at similar elevations, and are within 1km of the mean. Dunes overlying and obscuring layered deposits do not contain hematite. Benches and breaks in slope near the boundaries of many layered deposits provide further evidence that the layers may represent in-place, stratigraphic units. Hematite in Capri Chasma may have formed in a single event, which involved deposition or reworking in standing water.

  5. Feeding into old age: long-term effects of dietary fatty acid supplementation on tissue composition and life span in mice

    Microsoft Academic Search

    Teresa G. Valencak; Thomas Ruf

    2011-01-01

    Smaller mammals, such as mice, possess tissues containing more polyunsaturated fatty acids (PUFAs) than larger mammals, while\\u000a at the same time live shorter lives. These relationships have been combined in the ‘membrane pacemaker hypothesis of aging’.\\u000a It suggests that membrane PUFA content might determine an animal’s life span. PUFAs in general and certain long-chain PUFAs\\u000a in particular, are highly prone

  6. Correlations between multiple sclerosis functional composite, expanded disability status scale and health-related quality of life during and after treatment of relapses in patients with multiple sclerosis

    Microsoft Academic Search

    Serkan Ozakbas; Inanc Cagiran; Burcu Ormeci; Egemen Idiman

    2004-01-01

    The measurement of the clinical manifestations of multiple sclerosis (MS) is difficult. In the present study, we examined the changes in measurement of functions during and after pulse methylprednisolon (MP) treatment of MS exacerbations using the MSFC and EDSS. Correlation between multiple sclerosis quality of life (MSQoL)-54, EDSS and MSFC were studied. Thirty-six clinically definite MS patients were included in

  7. Uptake, transfer and distribution of silver and cobalt in tissues of the common cuttlefish Sepia officinalis at different stages of its life cycle

    E-print Network

    Paris-Sud XI, Université de

    officinalis at different stages of its life cycle P. Bustamante1, *, J.-L. Teyssié2 , B. Danis3 , S. W. Fowler experiments were conducted on adult cuttlefish and their eggs/embryos in order to assess bioaccumulation patterns at different stages of the organism's life cycle. Eggs, juveniles and adults readily accumulated

  8. PSN\\/PFL Curve Approach Using Three-Parameter Weibull Distribution for Life and Fatigue Analysis of Structural and Rolling Contact Components

    Microsoft Academic Search

    SHIGEO SHIMIZU

    2005-01-01

    In almost all cases of the estimation of fatigue limit for structural materials and bearing steels, the practice of using S-N curves obtained by plotting the applied stress against the number of stress cycles has been continuing to date. It usually takes into account the probabilistic approach of dealing with the stress or force life for only median life. Therefore,

  9. Controls of oil family distribution and composition in nonmarine petroleum systems: A case study from Inner Mongolia Erlian basin, Northern China

    NASA Astrophysics Data System (ADS)

    Chen, Zhelong; Liu, Guangdi; Huang, Zhilong; Lu, Xuejun; Luo, Qiang; Ding, Xiujian

    2014-10-01

    The Erlian basin is a continental rift basin located in Inner Mongolia, Northern China. It is a typical representative of Cretaceous Northeast Asian Rift System, which includes many small petroliferous basins in Mongolia Republic and Northern China. Although Lower Cretaceous source rocks are understood to be most important in the Erlian petroleum systems, the precise identification of these source rock intervals and their determination on oil families distribution and composition are poorly understood in this tectonically complicated, nonmarine basin. New bulk data have been gathered from source rock intervals, oil sands and crude oil samples in eight main oil-producing subbasins. Geochemical analyses indicate that Lower Cretaceous Aershan formation (K1ba) and Tengger 1 formation (K1bt1) are two main source intervals in the Erlian basin and their source rock facies vary from profundal lacustrine to marginal lacustrine according to biomarker and trace elements calibration, the profundal lacustrine facies is characterised by brackish water and anoxic environment, which is similar to their correlative oils (Family 1 oils). The marginal lacustrine facies is characterised by freshwater and suboxic environment, which sourced the most common Family 2 oils. Meanwhile, different maturation processes exercise the second control on oil groups and their compositions, the profundal lacustrine source rocks characterised by their sulphur-rich kerogens lead to two oil groups (group 1 and group 2 oils), whose maturity range from low to normal; while, the marginal lacustrine source rock only lead to normal-maturity oils. At last, biodegradation affected the composition of a certain oils and formed group 4 heavy oils. In addition, short migration distance in small subbasins made the contamination or fractionation less notable in the Erlian basin.

  10. Bacterial and eukaryotic intact polar lipids in the eastern subtropical South Pacific: Water-column distribution, planktonic sources, and fatty acid composition

    NASA Astrophysics Data System (ADS)

    Van Mooy, Benjamin A. S.; Fredricks, Helen F.

    2010-11-01

    Fatty acids are generally the most abundant lipid molecules in plankton, and thus play a central role in the cycling of organic matter in the upper ocean. These fatty acids are primarily derived from intact polar diacylglycerolipids (IP-DAGs), which compose cell membranes in plankton. The molecular diversity of IP-DAGs in the upper ocean remains to be fully characterized, and the advent of high performance liquid chromatography/electrospray ionization-mass spectrometry (HPLC/ESI-MS) approaches have now provided the opportunity to readily analyze IP-DAGs from marine planktonic communities. We used HPLC/ESI-MS to determine the concentrations of three classes of phospholipids (phosphatidlyglycerol (PG), phosphatidylethanolamine (PE), and phosphatidylcholine (PC)), three classes of betaine lipids (diacylglyceryl trimethylhomoserine (DGTS), diacylglyceryl hydroxymethyl-trimethyl-?-alanine (DGTA), and diacylglyceryl carboxyhydroxymethylcholine (DGCC)), and three classes of glycolipids (monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), and sulfoquinovosyldiacylglycerol (SQDG)) in plankton filtered (>0.2 ?m) from seawater collected within the euphotic zone of the eastern South Pacific. The distributions of these IP-DAGs along the cruise transect provided important new insights on their tentative planktonic sources. Complementary data from our cruise, a principle components analysis of our IP-DAG concentrations, observed fatty acid compositions of IP-DAG classes and published IP-DAG distributions in pure cultures of plankton suggest that heterotrophic bacteria were the dominant sources of PG and PE, while MGDG and SQDG originated primarily from Prochlorophytes. The origins of the other classes of IP-DAGs were less clear, although it is likely that PC, DGTS, DGTA, and DGCC were derived primarily from eukaryotic phytoplankton. The molecular distributions of fatty acids attached to the different classes of IP-DAGs were generally distinct from one another, and suggest that reported distributions of total fatty acids (as analyzed by gas chromatography) in the literature should be regarded as homogenized mixtures of distinct molecular pools of fatty acids.

  11. Molecular composition and size distribution of sugars, sugar-alcohols and carboxylic acids in airborne particles during a severe urban haze event caused by wheat straw burning

    NASA Astrophysics Data System (ADS)

    Wang, Gehui; Chen, Chunlei; Li, Jianjun; Zhou, Bianhong; Xie, Mingjie; Hu, Shuyuan; Kawamura, Kimitaka; Chen, Yan

    2011-05-01

    Molecular compositions and size distributions of water-soluble organic compounds (WSOC, i.e., sugars, sugar-alcohols and carboxylic acids) in particles from urban air of Nanjing, China during a severe haze event caused by field burning of wheat straw were characterized and compared with those in the summer and autumn non-haze periods. During the haze event levoglucosan (4030 ng m -3) was the most abundant compound among the measured WSOC, followed by succinic acid, malic acid, glycerol, arabitol and glucose, being different from those in the non-haze samples, in which sucrose or azelaic acid showed a second highest concentration, although levoglucosan was the highest. The measured WSOC in the haze event were 2-20 times more than those in the non-hazy days. Size distribution results showed that there was no significant change in the compound peaks in coarse mode (>2.1 ?m) with respect to the haze and non-haze samples, but a large difference in the fine fraction (<2.1 ?m) was found with a sharp increase during the hazy days mostly due to the increased emissions of wheat straw burning. Molecular compositions of organic compounds in the fresh smoke particles from wheat straw burning demonstrate that sharply increased concentrations of glycerol and succinic and malic acids in the fine particles during the haze event were mainly derived from the field burning of wheat straw, although the sources of glucose and related sugar-alcohols whose concentrations significantly increased in the fine haze samples are unclear. Compared to that in the fresh smoke particles of wheat straw burning an increase in relative abundance of succinic acid to levoglucosan during the haze event suggests a significant production of secondary organic aerosols during transport of the smoke plumes.

  12. Characterisation of the physical composition and microbial community structure of biofilms within a model full-scale drinking water distribution system.

    PubMed

    Fish, Katherine E; Collins, Richard; Green, Nicola H; Sharpe, Rebecca L; Douterelo, Isabel; Osborn, A Mark; Boxall, Joby B

    2015-01-01

    Within drinking water distribution systems (DWDS), microorganisms form multi-species biofilms on internal pipe surfaces. A matrix of extracellular polymeric substances (EPS) is produced by the attached community and provides structure and stability for the biofilm. If the EPS adhesive strength deteriorates or is overcome by external shear forces, biofilm is mobilised into the water potentially leading to degradation of water quality. However, little is known about the EPS within DWDS biofilms or how this is influenced by community composition or environmental parameters, because of the complications in obtaining biofilm samples and the difficulties in analysing EPS. Additionally, although biofilms may contain various microbial groups, research commonly focuses solely upon bacteria. This research applies an EPS analysis method based upon fluorescent confocal laser scanning microscopy (CLSM) in combination with digital image analysis (DIA), to concurrently characterize cells and EPS (carbohydrates and proteins) within drinking water biofilms from a full-scale DWDS experimental pipe loop facility with representative hydraulic conditions. Application of the EPS analysis method, alongside DNA fingerprinting of bacterial, archaeal and fungal communities, was demonstrated for biofilms sampled from different positions around the pipeline, after 28 days growth within the DWDS experimental facility. The volume of EPS was 4.9 times greater than that of the cells within biofilms, with carbohydrates present as the dominant component. Additionally, the greatest proportion of EPS was located above that of the cells. Fungi and archaea were established as important components of the biofilm community, although bacteria were more diverse. Moreover, biofilms from different positions were similar with respect to community structure and the quantity, composition and three-dimensional distribution of cells and EPS, indicating that active colonisation of the pipe wall is an important driver in material accumulation within the DWDS. PMID:25706303

  13. Determination of Creep Life of Glass Fiber/Phenol Composite Filled with Carbon Nanotubes by Four-Point Flexural Creep Test

    NASA Astrophysics Data System (ADS)

    Xu, Anchang; Nozaki, Hiroshi; Bao, Limin; Kemmochi, Kiyoshi

    2012-01-01

    From the result of our existing research, there is a continuing problem that fiber-reinforced plastic (FRP) composites always break down because of cracks between the laminae for their particular laminated structure. To decrease the probability of cracking between laminae, carbon nanotubes (CNTs), which exhibit a high potential as reinforcement for polymers, were used to enhance the interlaminar strength and to obtain an FRP product with a higher longevity. Different mass fractions of CNTs were dispersed in phenol resin and made into FRP composites, with glass cloth serving as a reinforcement material. Subsequently, bending and creep tests revealed that, in certain percentage of cases, the bending strength and lifetime of FRP products were improved by increasing the CNTs mass fraction.

  14. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1988-01-01

    A decade long program to develop critical advanced composite technology in the areas of physical properties, structural concept and analysis, manufacturing, reliability, and life predictions is reviewed. Specific goals are discussed. The status of the chemical vapor deposition effects on carbon fiber properties; inelastic deformation of metal matrix laminates; fatigue damage in fibrous MMC laminates; delamination fracture toughness in thermoplastic matrix composites; and numerical analysis of composite micromechanical behavior are presented.

  15. Tool life modeling for evaluating the effects of cutting speed and reinforcements on the machining of particle reinforced metal matrix composites

    Microsoft Academic Search

    Metin Kök

    2010-01-01

    The wear of cutting tools in the machining of 2024Al alloy composites reinforced with Al2O3 particles using varying sizes and volume fractions of particles up to 23.3vol% was investigated by a turning process using\\u000a coated carbide tools K10 and TP30 at different cutting speeds. Machining tests were performed with a plan of experiments based\\u000a on the Taguchi method. The tool

  16. A unique hollow Li3VO4/carbon nanotube composite anode for high rate long-life lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Li, Qidong; Sheng, Jinzhi; Wei, Qiulong; An, Qinyou; Wei, Xiujuan; Zhang, Pengfei; Mai, Liqiang

    2014-09-01

    A unique hollow Li3VO4/CNT composite is synthesized via a facile method as an anode material in lithium batteries. Our work opens up the way for a promising material with high rate capability and good cycling stability due to its efficient Li+ diffusion and relatively high structure stability.A unique hollow Li3VO4/CNT composite is synthesized via a facile method as an anode material in lithium batteries. Our work opens up the way for a promising material with high rate capability and good cycling stability due to its efficient Li+ diffusion and relatively high structure stability. Electronic supplementary information (ESI) available: The crystal structure of Li3VO4; SEM image of hydroxylated CNT; Li3VO4 was etched using different dosages of water; TGA curves of Li3VO4 and the hollow Li3VO4/CNT composite; the production in one pot (360 mL) was weighed to be 3.5237 g; XRD pattern and rate performance of CNT; the capacity contribution ratio of CNTs and the hollow Li3VO4; EIS and phase diagram of Li3VO4 and Li3VO4/CNT after 30 cycles; ECs performance of Li3VO4 anode material compared with other previous works. See DOI: 10.1039/c4nr03119a

  17. Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes.

    PubMed

    Yang, Fan; Shi, Baoyou; Bai, Yaohui; Sun, Huifang; Lytle, Darren A; Wang, Dongsheng

    2014-08-01

    The chemical stability of iron corrosion scales and the microbial community of biofilm in drinking water distribution system (DWDS) can have great impact on the iron corrosion and corrosion product release, which may result in "red water" issues, particularly under the situation of source water switch. In this work, experimental pipe loops were set up to investigate the effect of sulfate on the dynamical transformation characteristics of iron corrosion products and bacterial community in old cast iron distribution pipes. All the test pipes were excavated from existing DWDS with different source water supply histories, and the test water sulfate concentration was in the range of 50-350 mg/L. Pyrosequencing of 16S rRNA was used for bacterial community analysis. The results showed that iron release increased markedly and even "red water" occurred for pipes with groundwater supply history when feed water sulfate elevated abruptly. However, the iron release of pipes with only surface water supply history changed slightly without noticeable color even the feed water sulfate increased multiply. The thick-layered corrosion scales (or densely distributed tubercles) on pipes with surface water supply history possessed much higher stability due to the larger proportion of stable constituents (mainly Fe3O4) in their top shell layer; instead, the rather thin and uniform non-layered corrosion scales on pipes with groundwater supply history contained relatively higher proportion of less stable iron oxides (e.g. ?-FeOOH, FeCO3 and green rust). The less stable corrosion scales tended to be more stable with sulfate increase, which was evidenced by the gradually decreased iron release and the increased stable iron oxides. Bacterial community analysis indicated that when switching to high sulfate water, iron reducing bacteria (IRB) maintained dominant for pipes with stable corrosion scales, while significant increase of sulfur oxidizing bacteria (SOB), sulfate reducing bacteria (SRB) and iron oxidizing bacteria (IOB) was observed for pipes with less stable corrosion scales. PMID:24784453

  18. Thermal strain along optical fiber in lightweight composite FOG : Brillouin-based distributed measurement and finite element analysis

    NASA Astrophysics Data System (ADS)

    Minakuchi, Shu; Sanada, Teruhisa; Takeda, Nobuo; Mitani, Shinji; Mizutani, Tadahito; Sasaki, Yoshinobu; Shinozaki, Keisuke

    2014-05-01

    Thermal strain significantly affects stability of fiber optic gyroscope (FOG) performance. This study investigates thermal strain development in a lightweight carbon fiber reinforced plastic (CFRP) FOG under thermal vacuum condition simulating space environment. First, we measure thermal strain distribution along an optical fiber in a CFRP FOG using a Brillouin-based high-spatial resolution system. The key strain profile is clarified and the strain development is simulated using finite element analysis. Finally, several constituent materials for FOG are quantitatively compared from the aspect of the maximum thermal strain and the density, confirming the clear advantage of CFRP.

  19. Age, geochemical composition, and distribution of Oligocene ignimbrites in the northern Sierra Nevada, California: Implications for landscape morphology, elevation, and drainage divide geography of the Nevadaplano

    USGS Publications Warehouse

    Cassel, E.J.; Calvert, A.T.; Graham, S.A.

    2009-01-01

    To gain a better understanding of the topographic and landscape evolution of the Cenozoic Sierra Nevada and Basin and Range, we combine geochemical and isotopic age correlations with palaeoaltimetry data from widely distributed ignimbrites in the northern Sierra Nevada, California. A sequence of Oligocene rhyolitic ignimbrites is preserved across the modern crest of the range and into the western foothills. Using trace and rare earth element geochemical analyses of volcanic glass, these deposits have been correlated to ignimbrites described and isotopically dated in the Walker Lane fault zone and in central Nevada (Henry et al., 2004, Geologic map of the Dogskin mountain quadrangle; Washoe County, Nevada; Faulds et al., 2005, Geology, v. 33, p. 505-508). Ignimbrite deposits were sampled within the northern Sierra Nevada and western Nevada, and four distinct geochemical compositions were identified. The majority of samples from within the northern Sierra Nevada have compositions similar to the tuffs of Axehandle Canyon or Rattlesnake Canyon, both likely sourced from the same caldera complex in either the Clan Alpine Mountains or the Stillwater Range, or to the tuff of Campbell Creek, sourced from the Desatoya Mountains caldera. New 40Ar/39Ar age determinations from these samples of 31.2, 30.9, and 28.7Ma, respectively, support these correlations. Based on an Oligocene palinspastic reconstruction of the region, our results show that ignimbrites travelled over 200km from their source calderas across what is now the crest of the Sierra Nevada, and that during that time, no drainage divide existed between the ignimbrite source calderas in central Nevada and sample locations 200km to the west. Palaeoaltimetry data from Sierra Nevada ignimbrites, based on the hydrogen isotopic composition of hydration water in glass, reflect the effect of a steep western slope on precipitation and indicate that the area had elevations similar to the present-day range. These combined results suggest that source calderas were likely located in a region of high elevation to the east of the Oligocene Sierra Nevada, which had a steep western slope that allowed for the large extent and broad distribution of the ignimbrites.

  20. Life stage-related differences in fatty acid composition of an obligate ectoparasite, the deer ked (Lipoptena cervi)-influence of blood meals and gender.

    PubMed

    Mustonen, Anne-Mari; Käkelä, Reijo; Paakkonen, Tommi; Nieminen, Petteri

    2015-01-01

    Metamorphosis and diet often influence fatty acid (FA) signatures (FAS) of insects. We investigated FAS in a hematophagous ectoparasite, the deer ked (Lipoptena cervi). Deer keds shed their wings upon attachment on the host and, thus, the FAS of an individual blood-fed imago/pupa in the fur of its host can be traced back to the blood FA profile of a single moose (Alces alces). Host blood and different life stages of deer keds were investigated for FA by gas chromatography. The FAS of life stages resembled each other more closely than the diet. Blood meals modified the FAS of both sexes but the FAS of the blood-fed females were closer to those of the prepupae/pupae. The parasitizing males had higher proportions of major saturated FA (SFA) and polyunsaturated FA (PUFA) than the females, which contained more monounsaturated FA (MUFA) with higher ratios of n-3/n-6 PUFA and unsaturated FA (UFA)/SFA. The proportions of 16:1n-7 were <1% in the blood but 18% (males) and 29% (females) in the blood-fed keds. Allocation of lipids to offspring by the females and possible accumulation of PUFA in male reproductive organs may have induced these sex-related differences. MUFA percentages and UFA/SFA ratios increased while SFA and many PUFA decreased from the reproducing females to the pupae. The diapausing pupae displayed lowered n-3/n-6 PUFA ratios and could have mobilized 16:0 and 18:3n-3 for the most fundamental metabolic processes. In conclusion, FAS are modified through the life stages of the deer ked possibly due to their different FA requirements. PMID:25223709

  1. Distribution and stable isotope composition of leaf wax n-alkanes as tracers for organic matter transport along hydrological transects in the NW Argentine Andes

    NASA Astrophysics Data System (ADS)

    Tofelde, Stefanie; Sachse, Dirk; Schildgen, Taylor; Strecker, Manfred R.

    2015-04-01

    The burial of organic matter in marine sediments represents the main long-term sink for reduced carbon in the global carbon cycle, with the fluvial system being the predominant transport mechanism. Organic matter deposited in marine and continental sediments contains valuable information on ecological and climatic conditions, and organic proxy data is thus often used in paleoclimate research. To use sedimentary records to investigate past environmental conditions in the terrestrial realm, processes dictating the transport of organic matter, including spatial and temporal resolution as well as the influence of climatic and tectonic processes, have to be understood. In this study, we test if a lipid biomarker based approach can be used to trace present-day organic matter sources in a fluvial watershed draining two intermontane basins in the southern-central Andes of NW Argentina, a tectonically active region with pronounced topographic, rainfall, and vegetation gradients. We investigated the distribution of long-chain leaf-wax n-alkanes, a terrestrial plant biomarker (and as such representative of terrestrially sourced carbon), in river sediments and coarse particulate organic matter (CPOM) along two altitudinal and hydrological gradients. We used n-alkane abundances and their stable carbon and hydrogen isotopic values as three independent parameters for source discrimination. Additionally, we analyzed the control of environmental parameters on the isotopic signatures in leaf-wax n-alkanes. The general pattern of n-alkane distribution in river sediments and CPOM samples in our study area suggest that vascular plants are the major source of riverine organic matter. The stable carbon isotopic composition of nC29 alkanes suggests a nearly exclusive input of C3 vegetation. Although C4 plants are present in the lower catchment areas, the total percentage is too low to have a detectable influence on the carbon isotopic composition in river sediment and CPOM samples. Considering environmental parameters, nC29 alkane ?13C values are significantly correlated with mean annual rainfall in the respective catchment area, with less negative ?13C values in drier areas (r = - 0.63, p < 0.01). The variability in stable hydrogen isotopic composition (?D) of nC29 alkanes is determined mostly by the ?D value of the source water and aridity. We find that the apparent fractionation (?app), defined as the difference in hydrogen isotopic composition of plant source waters and synthesized leaf-wax n-alkanes, is significantly correlated with aridity (r = -0.65, p < 0.005), with a smaller apparent fractionation in drier areas, as well as with mean annual rainfall (r = -0.59, p < 0.01), relative humidity (r = -0.56, p < 0.02), and actual evapotranspiration (r = -0.53, p < 0.05). Our data indicate that vascular plants are the major source of riverine organic matter, with their stable carbon and hydrogen isotopic compositions influenced by climatic parameters. Thus, on spatial scales covering large gradients in environmental parameters, the analysis of leaf-wax n-alkanes can be used for organic matter source assessment in orogenic settings.

  2. Preliminary data on the composition and distribution of polychaetes in the deep-water areas of the north-western part of the Sea of Japan

    NASA Astrophysics Data System (ADS)

    Alalykina, Inna

    2013-02-01

    During the SoJaBio expedition, the deep sea fauna of the north-western Sea of Japan was sampled in August-September 2010. From this study, 11 epibenthic sledge stations are analyzed, with a focus on species composition, diversity and distribution patterns of polychaetes. A total of 92 polychaete taxa belonging to 70 genera and 28 families and 3 indeterminate species were found. Twelve species and eight genera have not been reported from the Sea of Japan before, but were registered from other deep-sea basins. Calculation of diversity (Shannon-Wiener Index, Pielou's Evenness) showed that the upper bathyal of the Sea of Japan is an area of higher polychaete diversity than the abyssal plain. The increased richness and diversity here could possibly be explained by a zoogeographic overlapping with the shallower species' assemblages of the shelf. At a higher taxonomic level the polychaete fauna of the deep Sea of Japan does not seem to differ from that of other deep-sea regions world-wide. In depths below 2000 m about 30% polychaete species have wide distributional ranges.

  3. Equilibrium Compositional Distribution in Freestanding Ternary Semiconductor Quantum Dots: The Case of Inx)Ga1-xAs

    SciTech Connect

    Pandey, Sumeet C.; Maroudas, Dimitrios

    2011-01-01

    We report the findings of a systematic computational study that addresses the effects of surface segregation on the atomic distribution at equilibrium of constituent group-III atoms in freestanding ternary semiconductor InxGa1-xAs nanocrystals. Our analysis is based on density functional theory calculations in conjunction with Monte Carlo simulations of the freestanding nanocrystals using a DFT-re-parameterized valence force field description of interatomic interactions. We have determined the equilibrium concentration profiles as a function of nanocrystal size (d), composition (x), and temperature (T). The ranges of d, x, and T are explored and demonstrate surface segregation and phase separation that leads to different extents of alloying in the nanocrystal core and in the near-surface regions. We find that formation of core/shell-like quantum dots characterized by an In-deficient core and an In-rich shell with a diffuse interface is favored at equilibrium. The analysis elucidates the relationship between the constituent species distribution in the nanocrystal and the parameters that can be tuned experimentally to design synthesis routes for tailoring the properties of ternary quantum dots.

  4. Influences of Species Composition, Distribution, and Structure on Leaf to Footprint H2O and CO2 Fluxes at Two Boreal Regeneration Sites

    NASA Astrophysics Data System (ADS)

    Chasmer, L. E.; Giroux, K.; Petrone, R. M.; Kljun, N.; Devito, K. J.

    2012-12-01

    The composition, distribution, and structure of regenerating forest species within recently disturbed forest stands likely influence site net carbon and water balances, especially where vegetation canopy structure affects the penetration of light through canopies. Regenerating stands are structurally complex as species compete for light and resources. The ability to quantify the influence of vegetation structure and species type on energy and mass exchanges within these stands is an important challenge to land surface models. To address these problems, this study examines the relative contributions of regenerating boreal forest species: Populus tremuloides, Populus balsamifera, Betula papyrifera, Salix spp., Viburnum edule, and Rosa acicularis to energy and mass exchanges within north facing and south facing sloped sites located within the often arid Western Boreal Plain, Alberta Canada. A remote sensing fusion-based classification method using airborne scanning Light Detection And Ranging (LiDAR) and high resolution (spectral, spatial) WorldView-2 imagery are used to quantify the spatial distribution of vegetation species, structural characteristics, and micro-topography surrounding eddy covariance and meteorological instrumentation. Leaf porometry measurements of stomatal conductance for a range of structural characteristics and topographic positions per species type are linked to remote sensing data and scaled to eddy covariance estimates of water and CO2 fluxes using a directional 2D footprint model after accounting for meteorological drivers.

  5. South Pacific dissolved Nd isotope compositions and rare earth element distributions: Water mass mixing versus biogeochemical cycling

    NASA Astrophysics Data System (ADS)

    Molina-Kescher, Mario; Frank, Martin; Hathorne, Ed

    2014-02-01

    Despite its enormous extent and importance for global climate, the South Pacific has been poorly investigated in comparison to other regions with respect to chemical oceanography. Here we present the first detailed analysis of dissolved radiogenic Nd isotopes (?Nd) and rare earth elements (REEs) in intermediate and deep waters of the mid-latitude (˜40°S) South Pacific along a meridional transect between South America and New Zealand. The goal of our study is to gain better insight into the distribution and mixing of water masses in the South Pacific and to evaluate the validity of Nd isotopes as a water mass tracer in this remote region of the ocean. The results demonstrate that biogeochemical cycling (scavenging processes in the Eastern Equatorial Pacific) and release of LREEs from the sediment clearly influence the distribution of the dissolved REE concentrations at certain locations. Nevertheless, the Nd isotope signatures clearly trace water masses including AAIW (Antarctic Intermediate Water) (average ?Nd = -8.2 ± 0.3), LCDW (Lower Circumpolar Deep Water) (average ?Nd = -8.3 ± 0.3), NPDW (North Pacific Deep Water) (average ?Nd = -5.9 ± 0.3), and the remnants of NADW (North Atlantic Deep Water) (average ?Nd = -9.7 ± 0.3). Filtered water samples taken from the sediment-water interface under the deep western boundary current off New Zealand suggest that boundary exchange processes are limited at this location and highlight the spatial and temporal variability of this process. These data will serve as a basis for the paleoceanographic application of Nd isotopes in the South Pacific.

  6. Composition, size distribution, optical properties and radiative effects of re-suspended local mineral dust of Rome area by individual-particle microanalysis and radiative transfer modelling

    NASA Astrophysics Data System (ADS)

    Pietrodangelo, A.; Salzano, R.; Bassani, C.; Pareti, S.; Perrino, C.

    2015-05-01

    New information on the PM10 mineral dust from site-specific (Rome area, Latium) outcropped rocks, and on the microphysics, optical properties and radiative effects of mineral dust at local level were gained in this work. A multi-disciplinary approach was used, based on individual-particle scanning electron microscopy with X-ray energy-dispersive microanalysis (SEM XEDS), X-ray diffraction (XRD) analysis of dust, size distribution of mineral particles, and radiative transfer modelling (RTM).The mineral composition of Rome lithogenic PM10 varies between an end-member dominated by silicate minerals and one exclusively composed of calcite. The first is obtained from volcanic lithotypes, the second from travertine or limestones; lithogenic PM10 with intermediate composition derives mainly from siliciclastic rocks or marlstones of Rome area. Size and mineral species of PM10 particles of silicate-dominated dust types are tuned mainly by weathering and, to lesser extent, by debris formation or crystallization; chemical precipitation of CaCO3 plays a major role in calcite-dominated types. These differences are evidenced by the diversity of volume distributions, within either dust types, or mineral species. Further differences are observed between volume distributions of calcite from travertine (natural source) and from road dust (anthropic source), specifically on the width, shape and enrichment of the fine fraction (unimodal at 5 ?m a.d. for travertine, bimodal at 3.8 and 1.8 ?m a.d. for road dust). Log-normal probability density functions of volcanics and travertine dusts affect differently the single scattering albedo (SSA) and the asymmetry parameter (g) in the VISible and Near Infrared (NIR) regions, depending also on the absorbing/non-absorbing character of volcanics and travertine, respectively. The downward component of the BOA solar irradiance simulated by RTM for a volcanics-rich or travertine-rich atmosphere shows that volcanics contribution to the solar irradiance differs significantly from that of travertine in the NIR region, while similar contributions are modelled in the VIS.

  7. A model for predicting the damage and oxidation dependent life of SCS-6/Ti-B21S [0]4 metal matrix composite 

    E-print Network

    Foulk, James Wesley

    1997-01-01

    -t)21S is superior to all titanium alloys in terms of oxidation weight gain and oxide layer formation, minimal oxygen dissolution can form an embrittled layer which leads to premature composite failure. The author will develop a methodology to predict... in high temperature applications. Barring turbine engine components, only two aircraft to date have employed nickel alloys. The X-2 and the X-15 employed K-Monei and X-Inconel, respectively. The most famous of the X aircraft, the X-15 (1959), had a top...

  8. Proof test methodology for composites

    NASA Technical Reports Server (NTRS)

    Wu, Edward M.; Bell, David K.

    1992-01-01

    The special requirements for proof test of composites are identified based on the underlying failure process of composites. Two proof test methods are developed to eliminate the inevitable weak fiber sites without also causing flaw clustering which weakens the post-proof-test composite. Significant reliability enhancement by these proof test methods has been experimentally demonstrated for composite strength and composite life in tension. This basic proof test methodology is relevant to the certification and acceptance of critical composite structures. It can also be applied to the manufacturing process development to achieve zero-reject for very large composite structures.

  9. A Structural Framework for a Near-Minimal Form of Life: Mass and Compositional Analysis of the Helical Mollicute Spiroplasma melliferum BC3

    PubMed Central

    Trachtenberg, Shlomo; Schuck, Peter; Phillips, Terry M.; Andrews, S. Brian; Leapman, Richard D.

    2014-01-01

    Spiroplasma melliferum is a wall-less bacterium with dynamic helical geometry. This organism is geometrically well defined and internally well ordered, and has an exceedingly small genome. Individual cells are chemotactic, polar, and swim actively. Their dynamic helicity can be traced at the molecular level to a highly ordered linear motor (composed essentially of the proteins fib and MreB) that is positioned on a defined helical line along the internal face of the cell’s membrane. Using an array of complementary, informationally overlapping approaches, we have taken advantage of this uniquely simple, near-minimal life-form and its helical geometry to analyze the copy numbers of Spiroplasma’s essential parts, as well as to elucidate how these components are spatially organized to subserve the whole living cell. Scanning transmission electron microscopy (STEM) was used to measure the mass-per-length and mass-per-area of whole cells, membrane fractions, intact cytoskeletons and cytoskeletal components. These local data were fit into whole-cell geometric parameters determined by a variety of light microscopy modalities. Hydrodynamic data obtained by analytical ultracentrifugation allowed computation of the hydration state of whole living cells, for which the relative amounts of protein, lipid, carbohydrate, DNA, and RNA were also estimated analytically. Finally, ribosome and RNA content, genome size and gene expression were also estimated (using stereology, spectroscopy and 2D-gel analysis, respectively). Taken together, the results provide a general framework for a minimal inventory and arrangement of the major cellular components needed to support life. PMID:24586297

  10. Life Stress

    MedlinePLUS

    ... Traumatic Brain Injury Life Stress Health & Wellness Anger Stigma Suicide Prevention Families with Kids Alcohol and Drugs ... Resilience Satisfaction with Life Sexual Truama Sleep Spirituality Stigma Stress Work Adjustment Worry Videos Post-Traumatic Stress ...

  11. Suite versus composite statistics

    USGS Publications Warehouse

    Balsillie, J.H.; Tanner, W.F.

    1999-01-01

    Suite and composite methodologies, two statistically valid approaches for producing statistical descriptive measures, are investigated for sample groups representing a probability distribution where, in addition, each sample is probability distribution. Suite and composite means (first moment measures) are always equivalent. Composite standard deviations (second moment measures) are always larger than suite standard deviations. Suite and composite values for higher moment measures have more complex relationships. Very seldom, however, are they equivalent, and they normally yield statistically significant but different results. Multiple samples are preferable to single samples (including composites) because they permit the investigator to examine sample-to-sample variability. These and other relationships for suite and composite probability distribution analyses are investigated and reported using granulometric data.

  12. Recycling and Life Cycle Issues

    SciTech Connect

    Das, Sujit [ORNL

    2010-01-01

    This chapter addresses recycling and life cycle considerations related to the growing use of lightweight materials in vehicles. The chapter first addresses the benefit of a life cycle perspective in materials choice, and the role that recycling plays in reducing energy inputs and environmental impacts in a vehicle s life cycle. Some limitations of life cycle analysis and results of several vehicle- and fleet-level assessments are drawn from published studies. With emphasis on lightweight materials such as aluminum, magnesium, and polymer composites, the status of the existing recycling infrastructure and technological challenges being faced by the industry also are discussed.

  13. Molecular distribution and stable carbon isotopic composition of dicarboxylic acids, ketocarboxylic acids, and ?-dicarbonyls in size-resolved atmospheric particles from Xi'an City, China.

    PubMed

    Wang, Gehui; Kawamura, Kimitaka; Cheng, Chunlei; Li, Jianjun; Cao, Junji; Zhang, Renjian; Zhang, Ting; Liu, Suixin; Zhao, Zhuzi

    2012-05-01

    Size-resolved airborne particles (9-stages) in urban Xi'an, China, during summer and winter were measured for molecular distributions and stable carbon isotopic compositions of dicarboxylic acids, ketocarboxylic acids, and ?-dicarbonyls. To our best knowledge, we report for the first time the size-resolved differences in stable carbon isotopic compositions of diacids and related compounds in continental organic aerosols. High ambient concentrations of terephthalic (tPh, 379 ± 200 ng m(-3)) and glyoxylic acids (?C(2), 235 ± 134 ng m(-3)) in Xi'an aerosols during winter compared to those in other Chinese cities suggest significant emissions from plastic waste burning and coal combustions. Most of the target compounds are enriched in the fine mode (<2.1 ?m) in both seasons peaking at 0.7-2.1 ?m. However, summertime concentrations of malonic (C(3)), succinic (C(4)), azelaic (C(9)), phthalic (Ph), pyruvic (Pyr), 4-oxobutanoic (?C(4)), and 9-oxononanoic (?C(9)) acids, and glyoxal (Gly) in the coarse mode (>2.1 ?m) are comparable to and even higher than those in the fine mode (<2.1 ?m). Stable carbon isotopic compositions of the major organics are higher in winter than in summer, except oxalic acid (C(2)), ?C(4), and Ph. ?(13)C of C(2) showed a clear difference in sizes during summer, with higher values in fine mode (ranging from -22.8‰ to -21.9‰) and lower values in coarse mode (-27.1‰ to -23.6‰). The lower ?(13)C of C(2) in coarse particles indicate that coarse mode of the compound originates from evaporation from fine mode and subsequent condensation/adsorption onto pre-existing coarse particles. Positive linear correlations of C(2), sulfate and ?C(2) and their ?(13)C values suggest that ?C(2) is a key intermediate, which is formed in aqueous-phase via photooxidation of precursors (e.g., Gly and Pyr), followed by a further oxidation to produce C(2). PMID:22475345

  14. Design strategies for robust oxide fiber composites

    NASA Astrophysics Data System (ADS)

    Weaver, Jared H.

    The present study addresses two deficiencies with all-oxide, porous matrix continuous fiber ceramic matrix composites (CFCCs). First, composites with 2D fiber architectures exhibit poor delamination resistance because of the inherent weakness of the matrix. Second, even when designed to be nondensifying, the matrix can strengthen via surface diffusion and/or vapor transport at service temperatures, resulting in increased interfacial strength and decreased toughness. Three design strategies for overcoming these problems are probed: (i) woven 3D fiber architectures to improve delamination resistance, (ii) fugitive coatings to produce weak interfaces and extend the useful life of the composite, and (iii) in-situ fiber coating produced by infiltration of a monazite precursor solution into composites with interfacial gaps, in order to improve control of interface properties. With appropriate fiber preform design, addition of through-thickness reinforcement significantly enhances the delamination resistance without affecting the in-plane fiber bundle strength. It also leads, however, to the formation of large inplane drying cracks that may be detrimental to through-thickness conductivity. These cracks can be mitigated through the addition of large particles (>10mum) to the fine particulates (?1mum) normally used for the matrix. The use of vibration in conjunction with vacuum assisted slurry infiltration is key to improving the spatial distribution of the large particles and mitigating the drying cracks. Controlled, uniform fugitive carbon coatings on both 2D and 3D fiber preforms can be formed by a solution precursor route. When the coatings are oxidized, gaps are formed at the fiber-matrix interface. The gaps reduce the sliding resistance of the interface and enhance the fracture resistance of the composite. They also significantly extend the service life upon long-term high temperature exposure relative to comparable composites with uncoated fibers. As an alternative strategy to interface control, composites with interfacial gaps were infiltrated with a monazite precursor solution. After pyrolysis, a uniform monazite coating is formed around the fibers. This coating may prove beneficial in further extending the composite service life. These design strategies mitigate the problems inherent in porous-matrix CFCCs and, whether used individually or in conjunction with one another, should allow improved tailoring of composite properties for specific engineering applications.

  15. Life satisfaction in the new country: a multilevel longitudinal analysis of effects of culture and 5-HTT allele frequency distribution in country of origin.

    PubMed

    Kashima, Emiko S; Kent, Stephen; Kashima, Yoshihisa

    2015-01-01

    Life satisfaction of migrants to Australia from 17 countries, assessed at 4-5 months, 16-17 months and 3½ years after arrival, was analyzed with a longitudinal, multilevel analysis. The results indicated that migrants were more satisfied, if the national average life satisfaction was higher in their country of origin, after adjustment for individual-level income, age, and sex and a linear temporal trend. Simultaneously, the migrants were also happier if people in their country of origin had a higher frequency of 5-HTT long allele, a genotype known to be associated with resilience under life stresses. These two relationships were independent, suggesting that both culture and gene matter in international transitions. PMID:24532702

  16. Size distribution and source analysis of ionic compositions of aerosols in polluted periods at Xinken in Pearl River Delta (PRD) of China

    NASA Astrophysics Data System (ADS)

    Liu, Shang; Hu, Min; Slanina, Sjaak; He, Ling-Yan; Niu, Yu-Wen; Bruegemann, Erika; Gnauk, Thomas; Herrmann, Hartmut

    Size-resolved chemical composition of aerosol was investigated during the PRIDE intensive field campaign in October 2004 at Xinken, at Pearl River Delta (PRD), China. Xinken is a rural/coastal site located south of Guangzhou. Size-segregated particles were sampled using Micro-Orifice Uniform Deposit Impactors (MOUDI) in order to characterize regional aerosol pollution. The meteorological conditions during the measurements were stable with low wind speed, high temperature and high RH, leading to high concentrations of fine particles, especially due to secondary components. The average concentrations of PM 1.8 and PM 10 were 51±19 and 84±27 ?g m -3, respectively, with a ratio of PM 1.8/PM 10 0.64±0.09, which indicates that fine particles dominated in PM 10. Sulfate, nitrate and ammonium were major ionic components. Aerosol mass size distributions showed either two or three modes. Land-sea circulation brought back aged aerosols to the sampling site leading to an increase of the concentrations of sodium and chloride in aerosols. The "condensation mode" of sulfate, which was formed by gas-to-particle conversion, was in the size range of 0.32-0.56 ?m, and the "droplet mode" of sulfate was observed in the size range of 0.56-1.0 or 1.0-1.8 ?m. Nitrate was distributed evenly over fine and coarse particles. The analysis of measured and calculated equilibrium constant of NH 4NO 3 indicates that dissociation of NH 4NO 3 in daytime is favored, but that at night ammonium nitrate is stable and constitutes the fine mode nitrate, while the coarse mode nitrate may be formed by the reaction of HNO 3 and sea-salt or soil components. Chemical mass closures showed reasonable agreement.

  17. Distribution and composition pattern of polycyclic aromatic hydrocarbons in different tissues of sturgeons collected from Iranian coastline of the Caspian Sea.

    PubMed

    Mashroofeh, Abdulreza; Bakhtiari, Alireza Riyahi; Pourkazemi, Mohammad

    2015-02-01

    The levels of 16 polycyclic aromatic hydrocarbons (PAHs) were determined in the liver, kidney, gills and muscle tissues of Persian sturgeon (Acipenser persicus; n=16), and Stellate sturgeon (Acipenser stellatus; n=7) collected from coastal waters of the South Caspian Sea from March and April 2011. The distribution and composition pattern of PAHs in the different tissues of sturgeons, and the effects of lipid content in sturgeon tissues and the octanol-water partition coefficient (Kow) of PAHs congeners on them were analyzed. The levels of total PAHs in the various tissues of Persian sturgeon and Stellate sturgeon ranged from 2.095 to 6.587 and 1.942 to 6.206 ?g g(-1)dw, respectively. Stellate sturgeon showed significantly higher levels of heavy PAHs (? 4-rings) than Persian sturgeon. The analysis has revealed a high degree of differential accumulation of the studied PAHs in the tissues of the both species. Low molecular weight PAHs predominated in the sturgeons, accounting for 81.89% of the total PAHs. Among the sixteen tested PAHs, naphthalene was the most dominant congener, followed by phenanthrene and fluorene. The PAHs levels and distribution in the tissues of sturgeons are dependent on both the Kow of PAH congeners and the lipid content in these tissues. There was a significant positive relationship (r=0.868, p<0.005) between lipid content and PAHs levels. The statistically significant negative relationships (p<0.01) were found between log Kow and log-transformed PAHs levels for muscle tissues of both sturgeon species. PMID:25462300

  18. Particle sources over the Danube River delta, Black Sea based on distribution, composition and size using optics, imaging and bulk analyses

    NASA Astrophysics Data System (ADS)

    Karageorgis, A. P.; Gardner, W. D.; Mikkelsen, O. A.; Georgopoulos, D.; Ogston, A. S.; Assimakopoulou, G.; Krasakopoulou, E.; Oaie, Gh.; Secrieru, D.; Kanellopoulos, Th. D.; Pagou, K.; Anagnostou, Ch.; Papathanassiou, E.

    2014-03-01

    Optical measurements provide substantial information on the dynamics and composition of particulate matter in the open ocean and coastal waters. When calibrated with the analysis of simultaneously collected discrete bottle samples, (particulate matter concentration: PMC, particulate organic carbon concentration: POC, chlorophyll ? concentration: chl ?, particle volume concentration and particle size distribution measured in situ), optical proxies increase the vertical resolution of changes in particle properties in the water column. We report relationships of inherent optical properties (beam attenuation at 2 wavelengths, fluorescence) and bulk particle properties obtained in the NW Black Sea during October 2007. The Danube River delta area was heavily stratified at that time, mainly due to a sharp thermocline at 17-27 m. Beam cp and fluorescence were significantly correlated and showed highest values near the coast, with a decreasing trend offshore. In situ measured particle size distributions were characterized by modes at ~ 40 ?m, 20 ?m and 5 ?m. PMC, POC, and chl ? exhibited wide ranges of spatial variation, a common feature being the gradual decrease in concentrations from the coast to offshore. The POC:PMC and POC:chl ? ratios suggested a general predominance of biogenic material over terrigenous particles throughout the study area. The commonly accepted sequence of large phytoplanktonic species transitioning to smaller ones during summer-autumn was confirmed by light microscopy and SEM observations. Detritus of Chaetoceros sp. and other diatoms was the dominant component of particulate matter. The small percentage of terrigenous particles was surprising given the high riverine sediment loads suggesting that most of the sediment load flocculated and was deposited before reaching the delta. Given the lack of previous data in this area, our study may serve as a baseline or background to look for changes in future bio-optical and/or biogeochemical measurements.

  19. Chemical composition, molecular weight distribution, secondary structure and effect of NaCl on functional properties of walnut (Juglans regia L) protein isolates and concentrates.

    PubMed

    Mao, Xiao-Ying; Hua, Yu-Fei

    2014-08-01

    Chemical composition, molecular weight distribution, secondary structure and effect of sodium chloride concentration on functional properties of walnut protein isolates, concentrates and defatted walnut flour were study. Compared with walnut protein concentrates (75.6%) and defatted walnut flour (52.5%), walnut protein isolates contain a relatively high amount of protein (90.5%). The yield of walnut protein isolates and concentrates was 43.2% and 76.6%, respectively. In molecular weight distribution study, Walnut protein isolates showed one peak with molecular weight of 106.33 KDa (100%) and walnut protein concentrates showed four peaks with molecular weight of 16,725 KDa (0.8%),104.943 KDa(63.9%), 7.3 KDa (11.4%), 2.6 KDa (23.9%). The secondary structure of walnut protein isolates was similar to that of walnut protein concentrates, but was differ from that of defatted walnut flour. The addition of sodium chloride (0?~?1 M) could improve the functionality of walnut protein concentrates, isolates and defatted walnut flour. The maximum solubility, water absorption capacity, emulsifying properties and foaming properties of walnut protein isolates, concentrates and defatted walnut flour were at sodium chloride solutions of 1.0 M, 0.6 M, 0.4 M, 0.6 M, respectively. The solubility of walnut protein concentrates (32.5%) in distilled water with 0 M sodium chloride was lower than that of walnut protein isolates (35.2%). The maximum solubility of walnut protein isolates, concentrates and defatted walnut flour in solution were 36.8%, 33.7% and 9.6% at 1.0 M sodium chloride solutions, respectively. As compared with other vegetable proteins, walnut protein isolates and concentrates exhibited better emulsifying properties and foam stability. PMID:25114337

  20. Integrating Distributed Algorithms into Distributed Systems

    E-print Network

    Freytag, Johann-Christoph

    ; Compositionality; Temporal Logic. 1 Introduction Distributed algorithms solve abstract versions of significantIntegrating Distributed Algorithms into Distributed Systems Ekkart Kindler and Sibylle Peuker algorithms are often part of a larger distributed system. Usually, the properties of the algorithm are proven