Sample records for chemical composition by material content

  1. Minerals by Chemical Composition

    NSDL National Science Digital Library

    This interactive periodic table displays a listing of minerals by element, sorted by percent of the element. Clicking on a symbol on the table leads users to information on the element (atomic mass and number, name origin, year of discovery, and a brief description), and to a table listing each mineral known to contain the element in decreasing order by percentage. Each mineral name in the table is linked to additional information on the mineral, such as formula and composition, images, crystallography, physical properties, and many others.

  2. Standard Test Methods for Constituent Content of Composite Materials

    E-print Network

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 These test methods determine the constituent content of composite materials by one of two approaches. Method I physically removes the matrix by digestion or ignition by one of seven procedures, leaving the reinforcement essentially unaffected and thus allowing calculation of reinforcement or matrix content (by weight or volume) as well as percent void volume. Method II, applicable only to laminate materials of known fiber areal weight, calculates reinforcement or matrix content (by weight or volume), and the cured ply thickness, based on the measured thickness of the laminate. Method II is not applicable to the measurement of void volume. 1.1.1 These test methods are primarily intended for two-part composite material systems. However, special provisions can be made to extend these test methods to filled material systems with more than two constituents, though not all test results can be determined in every case. 1.1.2 The procedures contained within have been designed to be particularly effective for ce...

  3. Chemical resistance, void content and tensile properties of oil palm\\/jute fibre reinforced polymer hybrid composites

    Microsoft Academic Search

    M. Jawaid; H. P. S. Abdul Khalil; A. Abu Bakar; P. Noorunnisa Khanam

    2011-01-01

    Tri layer hybrid composites of oil palm empty fruit bunches (EFB) and jute fibres was prepared by keeping oil palm EFB as skin material and jute as the core material and vice versa. The chemical resistance, void content and tensile properties of oil palm EFB\\/Jute composites was investigated with reference to the relative weight of oil palm EFB\\/Jute, i.e. 4:1,

  4. Characterization of nanostructured PbO2–PANi composite materials synthesized by combining electrochemical and chemical methods

    NASA Astrophysics Data System (ADS)

    Binh Phan, Thi; Tot Pham, Thi; Thanh Thuy Mai, Thi

    2013-03-01

    Nanostructured PbO2–PANi composite materials were prepared by combining electrochemical and chemical methods. Firstly, PbO2 was deposited on a stainless steel substrate by pulsed current method and then obtained PbO2 electrode was immersed into acidic aniline solution to form nanostructured PbO2–PANi composites. The synthesized samples were characterized by infrared (IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction (XRD). The electrocatalytic oxidation of methanol on those composites was evaluated by potentiodynamic polarization from 1.4 to 2.2 V versus Ag/AgCl/saturated KCl electrode. The adsorption of N–H group as well as the presence of benzoid and quinoid ring vibrations on IR-spectrum asserts that PANi coexisted with ?-PbO2 which is evidenced by x-ray analysis. With increasing immersion times of the PbO2 electrode in the acidic aniline solution the electrocatalytic performance of the obtained PbO2–PANi composites for methanol oxidation was improved due to the formation of less closely knitted nano-sized PANi fibers, which was confirmed by surface morphology analysis.

  5. Development of chemical vapor composites, CVC materials. Final report

    SciTech Connect

    NONE

    1998-10-05

    Industry has a critical need for high-temperature operable ceramic composites that are strong, non-brittle, light weight, and corrosion resistant. Improvements in energy efficiency, reduced emissions and increased productivity can be achieved in many industrial processes with ceramic composites if the reaction temperature and pressure are increased. Ceramic composites offer the potential to meet these material requirements in a variety of industrial applications. However, their use is often restricted by high cost. The Chemical Vapor composite, CVC, process can reduce the high costs and multiple fabrication steps presently required for ceramic fabrication. CVC deposition has the potential to eliminate many difficult processing problems and greatly increase fabrication rates for composites. With CVC, the manufacturing process can control the composites` density, microstructure and composition during growth. The CVC process: can grow or deposit material 100 times faster than conventional techniques; does not require an expensive woven preform to infiltrate; can use high modulus fibers that cannot be woven into a preform; can deposit composites to tolerances of less than 0.025 mm on one surface without further machining.

  6. Composite Materials

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Langley Research Center researchers invented an advanced polymer, a chemical compound formed by uniting many small molecules to create a complex molecule with different chemical properties. The material is a thermoplastic polyimide that resists solvents. Other polymers of this generic type are soluble in solvents, thus cannot be used where solvents are present. High Technology Services (HTS), Inc. licensed technology and is engaged in development and manufacture of high performance plastics, resins and composite materials. Techimer Materials Division is using technology for composite matrix resins that offer heat resistance and protection from radiation, electrical and chemical degradation. Applications of new polymer include molding resins, adhesives and matrix resins for fiber reinforced composites.

  7. Fast, Contactless Monitoring of the Chemical Composition of Raw Materials

    NASA Astrophysics Data System (ADS)

    Ivanov, O.; Stoyanov, Zh.; Stoyanov, B.; Nadoliisky, M.; Vaseashta, Ashok

    A technique to monitor chemical composition of materials during manufacturing of ceramic products, in particular - of bricks, is investigated. The technique of monitoring is likely to offset environmental pollution and save energy. For this purpose, we use the Surface photo charge effect, which is generated for each solid body interacting with electromagnetic field. The measurement is express and can be performed in-situ in production conditions. The experimental work has shown that different samples of the investigated materials with different compositions produce different signals specific to each sample. For the same material, the signal varies with the change in chemical composition. More specifically, it is shown that for the material from which the bricks are fired, the signal is a function of the percentage of coal sludge. The results indicate that the characterization technique as a viable technique for control of incoming raw materials.

  8. Composite-Material Tanks with Chemically Resistant Liners

    NASA Technical Reports Server (NTRS)

    DeLay, Thomas K.

    2004-01-01

    Lightweight composite-material tanks with chemically resistant liners have been developed for storage of chemically reactive and/or unstable fluids . especially hydrogen peroxide. These tanks are similar, in some respects, to the ones described in gLightweight Composite-Material Tanks for Cryogenic Liquids h (MFS-31379), NASA Tech Briefs, Vol. 25, No. 1 (January, 2001), page 58; however, the present tanks are fabricated by a different procedure and they do not incorporate insulation that would be needed to prevent boil-off of cryogenic fluids. The manufacture of a tank of this type begins with the fabrication of a reusable multisegmented aluminum mandrel in the shape and size of the desired interior volume. One or more segments of the mandrel can be aluminum bosses that will be incorporated into the tank as end fittings. The mandrel is coated with a mold-release material. The mandrel is then heated to a temperature of about 400 F (approximately equal to 200 C) and coated with a thermoplastic liner material to the desired thickness [typically approxiamtely equal to 15 mils (approximately equal to 0.38 mm)] by thermal spraying. In the thermal-spraying process, the liner material in powder form is sprayed and heated to the melting temperature by a propane torch and the molten particles land on the mandrel. The sprayed liner and mandrel are allowed to cool, then the outer surface of the liner is chemically and/or mechanically etched to enhance bonding of a composite overwrap. The etched liner is wrapped with multiple layers of an epoxy resin reinforced with graphite fibers; the wrapping can be done either by manual application of epoxy-impregnated graphite cloth or by winding of epoxy-impregnated filaments. The entire assembly is heated in an autoclave to cure the epoxy. After the curing process, the multisegmented mandrel is disassembled and removed from inside, leaving the finished tank. If the tank is to be used for storing hydrogen peroxide, then the liner material should be fluorinated ethylene/propylene (FEP), and one or more FEP O ring(s) should be used in the aluminum end fitting(s). This choice of materials is dictated by experimental observations that pure aluminum and FEP are the only materials suitable for long-term storage of hydrogen peroxide and that other materials tend to catalyze the decomposition of hydrogen peroxide to oxygen and water. Other thermoplastic liner materials that are suitable for some applications include nylon 6 and polyethylene. The processing temperatures for nylon 6 are lower than those for FEP. Nylon 6 is compatible with propane, natural gas, and other petroleum-based fuels. Polyethylene is compatible with petroleum- based products and can be used for short-term storage of hydrogen peroxide.

  9. Boron Nitride Composites By Chemical Vapor Deposition

    Microsoft Academic Search

    Hugh O. Pierson

    1975-01-01

    Composites of boron nitride (BN) have been made by the chemical vapor deposition (CVD) of a BN matrix on a BN felt fiber substrate. Reactant gases were boron trifluoride and ammonia. The composites have a relatively high density (1.70 g\\/cm3), a crystallite size LC = 150 A and an interlayer spacing d002 = 3.35 A. Measurements of elastic modulus and

  10. Chemical Composition

    NASA Astrophysics Data System (ADS)

    May, Willie; Cavanagh, Richard; Turk, Gregory; Winchester, Michael; Travis, John; Smith, Melody; Derose, Paul; Choquette, Steven; Kramer, Gary; Sieber, John; Greenberg, Robert; Lindstrom, Richard; Lamaze, George; Zeisler, Rolf; Schantz, Michele; Sander, Lane; Phinney, Karen; Welch, Michael; Vetter, Thomas; Pratt, Kenneth; Scott, John; Small, John; Wight, Scott; Stranick, Stephan

    Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and nutrition, agriculture, environmental technologies, chemicals and materials, instrumentation, electronics, forensics, energy, and transportation.

  11. Multifunctional composite materials for catalysis and chemical mechanical planarization

    Microsoft Academic Search

    Cecil A. Coutinho

    2009-01-01

    Composite materials formed from two or more functionally different materials offer a versatile avenue to create a tailored material with well defined traits. Within this dissertation research, multi-functional composites were synthesized based on organic and inorganic materials. The functionally of these composites was experimentally tested and a semi-empirical model describing the sedimentation behavior of these particles was developed. This first

  12. Chemical Composition

    Microsoft Academic Search

    Willie May; Richard Cavanagh; Gregory Turk; Michael Winchester; John Travis; Melody Smith; Paul Derose; Steven Choquette; Gary Kramer; John Sieber; Robert Greenberg; Richard Lindstrom; George Lamaze; Rolf Zeisler; Michele Schantz; Karen Phinney; Michael Welch; Thomas Vetter; Kenneth Pratt; John Scott; John Small; Scott Wight; Stephan Stranick

    2006-01-01

    Measurements of the chemical compositions of materials and the levels of certain substances in them are vital when assessing and improving public health, safety and the environment, are necessary to ensure trade equity, and are required when monitoring and improving industrial products and services. Chemical measurements play a crucial role in most areas of the economy, including healthcare, food and

  13. Flood pulse influence and anthropic impact on the chemical composition and energy content of Oryza glumaepatula in an Amazonian lake.

    PubMed

    Enrich-Prast, A; Esteves, F A

    2005-08-01

    The aim of this research was to study the flood pulse influence and the anthropic impact caused by bauxite tailings on the chemical composition of O. glumaepatula in Batata lake (PA, Brazil). Sampling was carried out in stands of O. glumaepatula in the low-water, filling, high-water, and drawdown periods in impacted and natural areas of Batata lake. During the low-water and drawdown periods the stands of O. glumaepatula were exposed, and in the filling and high-water periods the water depth was respectively 1.4 and 3.8 m. The collected material was dried at 70 degrees C, ground, and concentrations of total phosphorus, total nitrogen, organic carbon, and energy content were determined. The results indicate that the biomass increase, caused by the rise in water level, has a dilution effect on nitrogen and phosphorus concentrations in O. glumaepatula. The energy contents did not present significant differences in any of the studied periods. The results suggest that from the low water to filling period, nitrogen becomes more limiting to O. glumaepatula in the impacted area, whereas phosphorus becomes more limiting in the natural area. The population of O. glumaepatula contributes to the recovery of the impacted area of Batata lake as the detritus from this species accumulates over the sediment. This accumulation impedes future re-suspension of the bauxite tailings and increases the organic matter and nutrient concentrations in the impacted sediment. PMID:16341423

  14. Autonomic composite hydrogels by reactive printing: materials and oscillatory response.

    PubMed

    Kramb, R C; Buskohl, P R; Slone, C; Smith, M L; Vaia, R A

    2014-03-01

    Autonomic materials are those that automatically respond to a change in environmental conditions, such as temperature or chemical composition. While such materials hold incredible potential for a wide range of uses, their implementation is limited by the small number of fully-developed material systems. To broaden the number of available systems, we have developed a post-functionalization technique where a reactive Ru catalyst ink is printed onto a non-responsive polymer substrate. Using a succinimide-amine coupling reaction, patterns are printed onto co-polymer or biomacromolecular films containing primary amine functionality, such as polyacrylamide (PAAm) or poly-N-isopropyl acrylamide (PNIPAAm) copolymerized with poly-N-(3-Aminopropyl)methacrylamide (PAPMAAm). When the films are placed in the Belousov-Zhabotinsky (BZ) solution medium, the reaction takes place only inside the printed nodes. In comparison to alternative BZ systems, where Ru-containing monomers are copolymerized with base monomers, reactive printing provides facile tuning of a range of hydrogel compositions, as well as enabling the formation of mechanically robust composite monoliths. The autonomic response of the printed nodes is similar for all matrices in the BZ solution concentrations examined, where the period of oscillation decreases in response to increasing sodium bromate or nitric acid concentration. A temperature increase reduces the period of oscillations and temperature gradients are shown to function as pace-makers, dictating the direction of the autonomic response (chemical waves). PMID:24651297

  15. Dependence of demagnetizing fields in Fe-based composite materials on magnetic particle size and the resin content

    NASA Astrophysics Data System (ADS)

    Kollár, Peter; Bir?áková, Zuzana; Vojtek, Vladimír; Füzer, Ján; Bureš, Radovan; Fáberová, Mária

    2015-08-01

    Demagnetizing fields are in general produced by the volume and surface magnetic poles. The structure of soft magnetic composite materials, where the ferromagnetic particles are insulated from each other, causes the formation of demagnetizing fields produced by the particle surfaces. These fields depend on the amount of insulation and on the shapes, clustering and distribution of ferromagnetic particles. In this work the demagnetizing fields in iron-phenolphormaldehyde resin composite samples were investigated experimentally using the method for determining the demagnetization factor from the anhysteretic magnetization curve measurement. The initial magnetization curves were calculated for an ideal composite with 100% filler content using the values of the demagnetization factor. The results on the "ideal" permeability show differences between the samples with different resin content for each granulometric class, which tells about the internal stresses introduced into ferromagnetic material during the compaction process.

  16. Thermal and Chemical Characterization of Composite Materials. MSFC Center Director's Discretionary Fund Final Report, Project No. ED36-18

    NASA Technical Reports Server (NTRS)

    Stanley, D. C.; Huff, T. L.

    2003-01-01

    The purpose of this research effort was to: (1) provide a concise and well-defined property profile of current and developing composite materials using thermal and chemical characterization techniques and (2) optimize analytical testing requirements of materials. This effort applied a diverse array of methodologies to ascertain composite material properties. Often, a single method of technique will provide useful, but nonetheless incomplete, information on material composition and/or behavior. To more completely understand and predict material properties, a broad-based analytical approach is required. By developing a database of information comprised of both thermal and chemical properties, material behavior under varying conditions may be better understood. THis is even more important in the aerospace community, where new composite materials and those in the development stage have little reference data. For example, Fourier transform infrared (FTIR) spectroscopy spectral databases available for identification of vapor phase spectra, such as those generated during experiments, generally refer to well-defined chemical compounds. Because this method renders a unique thermal decomposition spectral pattern, even larger, more diverse databases, such as those found in solid and liquid phase FTIR spectroscopy libraries, cannot be used. By combining this and other available methodologies, a database specifically for new materials and materials being developed at Marshall Space Flight Center can be generated . In addition, characterizing materials using this approach will be extremely useful in the verification of materials and identification of anomalies in NASA-wide investigations.

  17. Structural Health Monitoring of Smart Composite Material by Acoustic Emission

    E-print Network

    Paris-Sud XI, Université de

    Structural Health Monitoring of Smart Composite Material by Acoustic Emission S. Masmoudia , A. El fabricated in E-glass fibre/epoxy with a unidirectional play laminate. The composite specimens with sensors composite structures gives the opportunity to develop smart materials for health monitoring systems

  18. FY98 Final Report Initial Interfacial Chemical Control for Enhancement of Composite Material Strength

    SciTech Connect

    GE Fryxell; KL Alford; KL Simmons; RD Voise; WD Samuels

    1999-10-14

    The U.S. Army Armament Research Development and Engineering Center (ARDEC) sponsored this research project to support the development of new self-assembled monolayer fiber coatings. These coatings can greatly increase the bond strength between the fiber and the resin matrix of a composite material. Composite ammunition components molded from such materials will exhibit higher strength than current materials, and will provide a major improvement in the performance of composites in military applications. Use of composite materials in military applications is desirable because of the lighter weight of the materials and their high strengths. The FY97 project investigated initial interfacial chemical control for enhancement of composite material strength. The core of the project was to modify the covalent interface of glass fibers (or other reinforcing fibers) to induce strong, uniform, defect-free adhesion between the fibers' surfaces and the polymer matrix. Installing a self-assembled monolayer tailored to the specific matrix resin accomplished this. Simply, the self-assembled monolayer modifies the fiber to make it appear to have the same chemical composition as the resin matrix. The self-assembled monolayer creates a receptive, hydrophobic interface that the thermoset resin (or polymer precursors) would wet more effectively, leading to a higher contact surface area and more efficient adhesion. The FY97 work phase demonstrated that it is possible to increase the adhesive strength, as well as increase the heat deflection temperature through the use of self-assembled monolayer.

  19. The effects of space radiation on a chemically modified graphite-epoxy composite material

    NASA Technical Reports Server (NTRS)

    Reed, S. M.; Herakovich, C. T.; Sykes, G. F.

    1986-01-01

    The effects of the space environment on the engineering properties and chemistry of a chemically modified T300/934 graphite-epoxy composite system are characterized. The material was subjected to 1.0 x 10 to the 10th power rads of 1.0 MeV electron irradiation under vacuum to simulate 30 years in geosynchronous earth orbit. Monotonic tension tests were performed at room temperature (75 F/24 C) and elevated temperature (250 F/121 C) on 4-ply unidirectional laminates. From these tests, inplane engineering and strength properties (E sub 1, E sub 2, Nu sub 12, G sub 12, X sub T, Y sub T) were determined. Cyclic tests were also performed to characterize energy dissipation changes due to irradiation and elevated temperature. Large diameter graphite fibers were tested to determine the effects of radiation on their stiffness and strength. No significant changes were observed. Dynamic-mechanical analysis demonstrated that the glass transition temperature was reduced by 50 F(28 C) after irradiation. Thermomechanical analysis showed the occurrence of volatile products generated upon heating of the irradiated material. The chemical modification of the epoxy did not aid in producing a material which was more radiation resistant than the standard T300/934 graphite-epoxy system. Irradiation was found to cause crosslinking and chain scission in the polymer. The latter produced low molecular weight products which plasticize the material at elevated temperatures and cause apparent material stiffening at low stresses at room temperature.

  20. Preparation of functional composite materials based on chemically derived graphene using solution process

    NASA Astrophysics Data System (ADS)

    Kim, M.; Hyun, W. J.; Mun, S. C.; Park, O. O.

    2015-04-01

    Chemically derived graphenes were assembled into functional composite materials using solution process from stable solvent dispersion. We have developed foldable electronic circuits on paper substrates using vacuum filtration of graphene nanoplates dispersion and a selective transfer process without need for special equipment. The electronic circuits on paper substrates revealed only a small change in conductance under various folding angles and maintained an electronic path after repetitive folding and unfolding. We also prepared flexible. binder-free graphene paper-like materials by addition of graphene oxide as a film stabilizer. This graphene papers showed outstanding electrical conductivity up to 26,000 S/m and high charge capacity as an anode in lithium-ion battery without any post-treatments. For last case, multi-functional thin film structures of graphene nanoplates were fabricated by using layer-by-layer assembly technique, showing optical transparency, electrical conductivity and enhanced gas barrier property.

  1. Chemical Composition of Boron Carbonitride Films Grown by Plasma-Enhanced Chemical Vapor Deposition from Trimethylamineborane

    Microsoft Academic Search

    M. L. Kosinova; Yu. M. Rumyantsev; A. N. Golubenko; N. I. Fainer; B. M. Ayupov; I. P. Dolgovesova; B. A. Kolesov; V. V. Kaichev; F. A. Kuznetsov

    2003-01-01

    Boron carbonitride and boron nitride films were grown by plasma-enhanced chemical vapor deposition using trimethylamineborane and its mixtures with ammonia, hydrogen, or helium. The effects of the starting-mixture composition and substrate temperature on the chemical composition of the deposits was studied by ellipsometry, scanning microscopy, IR spectroscopy, Raman scattering, and x-ray photoelectron spectroscopy. The results indicate that the initial composition

  2. Composite chemical wastewater treatment by biofilm configured periodic discontinuous batch process operated in anaerobic metabolic function

    Microsoft Academic Search

    S. Venkata Mohan; N. Chandrasekhara Rao; P. N. Sarma

    2007-01-01

    Biofilm configured system with sequencing\\/periodic discontinuous batch mode operation was studied in anaerobic metabolic function for the treatment of composite chemical wastewater (low-biodegradable [low BOD\\/COD ratio ?0.31] and sulfate content, 1.75g\\/l). Inert stone chips were used as biofilm supporting material. Reactor was operated with a total cycle period of 24h (FILL: 15min; REACT (aeration with recirculation): 23h; SETTLE: 30min; DECANT:

  3. Refinery piping fires resulting from variations in chemical composition of piping materials

    SciTech Connect

    Setterlund, R.B. [Metallurgical Consultants, Inc., Houston, TX (United States)

    1996-07-01

    A number of refinery fires in recent years are traceable to variations in the chemical composition of piping materials. These fires are typically more destructive than those due to other causes and can take place without warning. Some, but not all, were the result of the inadvertent use of carbon steel in alloy steel piping systems. Others were the result of alloy welds in carbon steel systems while still others were due to variations in residual elements leading to anomalous corrosion behavior. Recommendations are given on areas of refinery units where the greatest need for close control of material composition exists.

  4. Molten salts\\/ceramic-foam matrix composites by melt infiltration method as energy storage material

    Microsoft Academic Search

    Jianfeng Wu; Jian Li; Xiaohong Xu; Lanfang Yang; Jufang Wu; Fang Zhao; Chuanguo Li

    2009-01-01

    A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding\\u000a SiC ceramic foam as matrix and Na2SO4 as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results\\u000a indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical

  5. Damage detection in composite materials by FBGs

    NASA Astrophysics Data System (ADS)

    Menendez, Jose M.; Munoz, Pedro; Pintado, J. M.; Guemes, Alfredo

    2004-06-01

    Embedded fiber Bragg gratings (FBGs) are sensitive to changes of near strain fields in a composite host monolithic structure, typical of aircraft airframes. FBGs have been embedded in different configurations (a typical position is the skin -- stiffener interface in a monolithic structure) for detecting events associated to damage occurrence. Thus, it is possible to think in FBGs not only as strain sensors, in a classical load monitoring configuration, but as a part of a structural health monitoring (SHM) system in composite structures dimensioned following damage tolerance criteria.

  6. Damage detection in composite materials by FBGs

    Microsoft Academic Search

    Jose M. Menendez; Pedro Munoz; J. M. Pintado; Alfredo Guemes

    2004-01-01

    Embedded fiber Bragg gratings (FBGs) are sensitive to changes of near strain fields in a composite host monolithic structure, typical of aircraft airframes. FBGs have been embedded in different configurations (a typical position is the skin -- stiffener interface in a monolithic structure) for detecting events associated to damage occurrence. Thus, it is possible to think in FBGs not only

  7. Composite material

    Microsoft Academic Search

    Stacy A. Hutchens; Jonathan Woodward; Barbara R. Evans; Hugh M. ONeill

    2012-01-01

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft

  8. Composite material

    DOEpatents

    Hutchens, Stacy A. (Knoxville, TN); Woodward, Jonathan (Solihull, GB); Evans, Barbara R. (Oak Ridge, TN); O'Neill, Hugh M. (Knoxville, TN)

    2012-02-07

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  9. CHEMICAL COMPOSITION AND DIGESTIBILITY OF FIBER FRACTIONS OF CERTAIN BY-PRODUCT FEEDSTUFFS FED TO RUIVIINANTS

    Microsoft Academic Search

    K. A. Garleb; G. C. Fahey; S. M. Lewis; M. S. Kerley; L. Montgomery

    These experiments were conducted to study chemical composition of five by-product feedstuffs and their fiber fractions to determine the components that make up their indigesti- ble residue. Corn fiber (CF), coarse corn fiber (CCF), oat hulls (OH), soybean hulls (SH) and cottonseed hulls (CSH) were chemically fractionated into eight components: original by- product, chloroform-methanol (CHC13:CHaOH)-extracted material, NDF, lignin-carbohy- drate complex

  10. Chemical composition, dietary fibre and resistant starch contents of raw and cooked pea, common bean, chickpea and lentil legumes

    Microsoft Academic Search

    Giovana Ermetice de Almeida Costa; Keila da Silva Queiroz-Monici; Soely Maria Pissini Machado Reis; Admar Costa de Oliveira

    2006-01-01

    The chemical composition and the contents of resistant starch and soluble and insoluble dietary fibre of pea (Pisum sativum L.), common bean (Phaseolus vulgaris L.), chickpea (Cicer aretinum L.) and lentil (Lens culinaris Med.) legumes, were studied. Raw and freeze-dried cooked samples were used, both in the form of flour. Protein values of the legumes ranged from 18.5 to 21.9g\\/100g

  11. Grained composite materials prepared by combustion synthesis under mechanical pressure

    DOEpatents

    Dunmead, Stephen D. (Davis, CA); Holt, Joseph B. (San Jose, CA); Kingman, Donald D. (Danville, CA); Munir, Zuhair A. (Davis, CA)

    1990-01-01

    Dense, finely grained composite materials comprising one or more ceramic phase or phase and one or more metallic and/or intermetallic phase or phases are produced by combustion synthesis. Spherical ceramic grains are homogeneously dispersed within the matrix. Methods are provided, which include the step of applying mechanical pressure during or immediately after ignition, by which the microstructures in the resulting composites can be controllably selected.

  12. Effect of irradiation on the patulin content and chemical composition of apple juice concentrate.

    PubMed

    Zegota, H; Zegota, A; Bachman, S

    1988-09-01

    The influence of ionizing radiation on the patulin content of apple juice concentrate was investigated. The results indicated that patulin, at an initial concentration of about 2 mg/kg, disappeared after irradiation of the concentrate with doses as low as 2.5 kGy. For lower doses, the extent of patulin degradation was proportional to the absorbed dose. Irradiation of the concentrate with doses sufficient for patulin disappearance did not change the titratable acidity, the content of reducing sugars and carbonyl compounds or the amino acid composition. The content of ascorbic acid slightly decreased and the colour of the concentrate brightened. The intensity of the patulin absorption spectra after irradiation of mycotoxin in aqueous solutions decreased. PMID:3195248

  13. Damage-tolerant composite materials produced by stitching carbon fibers

    NASA Technical Reports Server (NTRS)

    Dow, Marvin B.; Smith, Donald L.

    1989-01-01

    NASA-Langley has undertaken the investigation of composite damage-tolerance enhancement and fabrication economies-maximization via reinforcement-stitching, in combination with resin transfer molding. Attention is given to results obtained by an experimental evaluation of composites tailored for damage tolerance by stitching layers of dry carbon-fiber fabric with closely-spaced threads, in order to furnish through-the-thickness reinforcement. Various stitching patterns and thread materials have been evaluated, using flat-plate specimens; blade-stiffened structural elements have been fabricated and tested. The results presented indicate that stitched laminates furnish damage tolerance performance comparable to that of more expensive, toughened-matrix composites.

  14. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Composites are lighter and stronger than metals. Aramid fibers like Kevlar and Nomex were developed by DuPont Corporation and can be combined in a honeycomb structure which can give an airplane a light, tough structure. Composites can be molded into many aerodynamic shapes eliminating rivets and fasteners. Langley Research Center has tested composites for both aerospace and non-aerospace applications. They are also used in boat hulls, military shelters, etc.

  15. Drying Sage ( Salvia officinalis L.) Plants and Its Effects on Content, Chemical Composition, and Radical Scavenging Activity of the Essential Oil

    Microsoft Academic Search

    Ibtissem Hamrouni Sellami; Iness Bettaieb Rebey; Jazia Sriti; Fatma Zohra Rahali; Ferid Limam; Brahim Marzouk

    Chemical composition and antioxidant activity of Salvia officinalis essential oil (EO) were studied under different drying methods of plant material. Results obtained showed that dried plant\\u000a material yielded more essential oils than did the fresh one. The highest EO yields were obtained by infrared drying at 45 °C\\u000a (0.39%) followed by air drying (0.30%) and oven drying at 45 °C (0.26%). The

  16. Deoiled asphalt as carbon source for preparation of various carbon materials by chemical vapor deposition

    Microsoft Academic Search

    Xuguang Liu; Yongzhen Yang; Xian Lin; Bingshe Xu; Yan Zhang

    2006-01-01

    Various carbon materials, including vapor grown carbon fibers (VGCFs) and carbon trees, were synthesized by chemical vapor deposition in argon atmosphere, using deoiled asphalt as carbon source and ferrocene as catalyst. Pure carbon microbeads (CMBs) were also obtained by this method in the absence of ferrocene. The influence of different growth parameters, such as ferrocene content, reaction temperature, retention time

  17. The correlationship between the metabolizable energy content, chemical composition and color score in different sources of corn DDGS

    PubMed Central

    2013-01-01

    Background This study was conducted to evaluate the apparent metabolizable energy (AME) and true metabolizable energy (TME) contents in 30 sources of corn distillers dried grains with solubles (DDGS) in adult roosters, and establish the prediction equations to estimate the AME and TME value based on its chemical composition and color score. Methods Twenty-eight sources of corn DDGS made from several processing plants in 11 provinces of China and others imported from the United States. DDGS were analyzed for their metabolizable energy (ME) contents, measured for color score and chemical composition (crude protein, crude fat, ash, neutral detergent fiber, acid detergent fiber), to predict the equation of ME in DDGS. A precision-fed rooster assay was used, each DDGS sample was tube fed (50 g) to adult roosters. The experiment was conducted as a randomized incomplete block design with 3 periods. Ninety-five adult roosters were used in each period, with 90 being fed the DDGS samples and 5 being fasted to estimate basal endogenous energy losses. Results Results showed that the AME ranged from 5.93 to 12.19 MJ/kg, TME ranged from 7.28 to 13.54 MJ/kg. Correlations were found between ME and ash content (-0.64, P?content of DDGS based on chemical composition and color score was AME?=?6.57111?+?0.51475 GE - 0.10003 NDF?+?0.13380 ADF?+?0.07057 fat - 0.57029 ash - 0.02437 L (R2?=?0.70). The best-fit regression equation for TME content of DDGS was TME?=?7.92283?+?0.51475 GE - 0.10003 NDF?+?0.13380 ADF?+?0.07057 fat - 0.57029 ash - 0.02437 L (R2?=?0.70). Conclusions This experiment suggested that measuring the chemical composition and color score of a corn DDGS sample may provide a quality parameter for identifying corn DDGS sources energy digestibility and metabolizable energy content. PMID:24066830

  18. Computational Chemical Materials Engineering

    E-print Network

    to understand behavior and properties of materials as a function of ­ Chemical constitution ­ Composition signature, recognition, shielding · Multifunctional composites · Biomaterials #12;Home Multi Functional-particles, nano-wires, nano-rods, nano-platelets ­ Fullerenes, nano tubes; dendrimers, hyper branched polymers

  19. Impact damage detection of composite materials by fiber Bragg gratings

    Microsoft Academic Search

    Zoran Djinovic; Michael Scheerer; Milos Tomic

    2011-01-01

    Usage of fiber-optic Bragg gratings (FBG) for strain measurement is well-known technique in structural health monitoring (SHM). However, this technique based on shift of spectral peak, suffers from different spurious signals, particularly caused by thermal effect. We present here a method for impact damage detection of composite materials based on FBG without thermal disturbance. This method is based on the

  20. CHEMICALS INCORPORATED IN NEST MATERIAL BY RED IMPORTED FIRE ANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red imported fire ants are believed to incorporate ant-derived chemicals in nesting material. However, only a few chemicals have been identified. One hurdle for such investigation is the interference in chemical analysis from soil-borne chemicals. Ants were found to be able to construct their nes...

  1. Superconducting properties, microstructure and chemical composition of MgB2 sheathed materials

    NASA Astrophysics Data System (ADS)

    Eyidi, D.; Eibl, O.; Wenzel, T.; Nickel, K. G.; Schlachter, S. I.; Goldacker, W.

    2003-07-01

    The superconducting properties, the microstructure and the chemical composition of sheathed MgB2 tapes and of one wire, all synthesized by the powder-in-tube method, were investigated. At 4.2 K critical current densities up to 105 A cm-2 (0 T) and 1.5 × 104 A cm-2 (2.5 T) were obtained by transport measurements in the wire and the tapes, respectively. In the MgB2 matrix of all samples, oxygen was identified and mole fractions of 0-10 at% were determined by electron probe microanalysis. It was found by scanning electron microscopy that only the tapes showed boron-rich secondary phases about 10 µm in size. Comparing different tapes, the critical currents increase with the aspect ratio and decrease with the oxygen mole fraction in the MgB2 material. In the tapes, aspect ratios were inhomogeneous and critical current densities at low fields were limited by insufficient thermal stabilization. For understanding the internal oxidation in the MgB2 tapes, one tape was investigated by analytical transmission electron microscopy (TEM). The combination of energy-dispersive x-ray spectroscopy and electron spectroscopic imaging in the TEM yielded phase maps of this sample. It showed a heterogeneous microstructure, MgB2 grain sizes ranged between 20 nm and 1 µm. Oxygen was primarily bound in 20 nm-1 µm MgO precipitates and secondary phases, and no boron oxides could be evidenced. Randomly distributed 50 nm-1 µm boron-rich secondary phases (MgB4+delta, MgB7+gamma) embedded in the MgB2 matrix were identified. The possible reasons for the oxidation of the superconducting matrix are discussed.

  2. Submicron-sized actuators based on enhanced shape memory composite material fabricated by FIB-CVD

    Microsoft Academic Search

    Dmitry Zakharov; Gor Lebedev; Artemy Irzhak; Veronika Afonina; Alexey Mashirov; Vladimir Kalashnikov; Viktor Koledov; Alexander Shelyakov; Dmitry Podgorny; Natalia Tabachkova; Vladimir Shavrov

    2012-01-01

    An enhanced scheme for a functional bilayered composite material with shape memory effect has been successfully applied on the microscale to fabricate a thermally controlled microactuator. Fabrication of cantilever-type microactuators from melt spun ribbon of TiNiCu shape memory alloy included electro-chemical polishing followed by focused ion beam milling and ion-assisted chemical vapor deposition of Pt elastic layer. The smallest working

  3. Associating Physical and Chemical Properties to Evaluate Buffer Materials by Th and U Sorption

    SciTech Connect

    Jan, Yi-Lin; Chen, Tzu-Yun; Cheng, Hwai-Ping; Hsu, Chun-Nan; Tseng, Chia-Liang; Wei,Yuan-Yaw; Yang, Jen-Yan; Ke, Cheng-Hsiung; Chuang, Jui-Tang; Teng, Shi-Ping

    2003-02-27

    The physical and chemical properties of buffer materials to be used for a radwaste disposal repository should be evaluated prior to use. In a conventional approach, independent studies of physical and/or chemical characteristics are conducted. This study investigated the relationship between the plastic index (PI) and distribution ratio (Rd) of buffer materials composed of varying ratios of quartz sand and bentonite. Thorium (Th) and Uranium (U) were the nuclides of interest, and both synthetic groundwater and seawater were used as the liquid phases to simulate conditions representative of deep geological disposal within an island. Atterberg tests were used to determine PI values, and batch sorption experiments were employed to measure Rd values. The results show that Th reached maximum sorption behavior when the bentonite content exceeded 30 % of the mixture. Contrariwise, the sorption of U increased linearly with bentonite content, up to bentonite contents of 100%, and this correlation was present regardless of the liquid phase used. A further result is that U has a better additivity with respect to Rd than Th in both synthetic groundwater and synthetic seawater. These results will allow a determination of more effective buffer material composition, and improved estimates of the overall Rd of the buffer material mixture from the Rd of each mineral component.

  4. Composite material dosimeters

    DOEpatents

    Miller, Steven D. (Richland, WA)

    1996-01-01

    The present invention is a composite material containing a mix of dosimeter material powder and a polymer powder wherein the polymer is transparent to the photon emission of the dosimeter material powder. By mixing dosimeter material powder with polymer powder, less dosimeter material is needed compared to a monolithic dosimeter material chip. Interrogation is done with excitation by visible light.

  5. Chemical composition and some trace element contents in coals and coal ash from Tamnava-Zapadno Polje Coal Field, Serbia

    SciTech Connect

    Vukasinovic-Pesic, V.; Rajakovic, L.J. [University of Montenegro, Podgorica (Montenegro)

    2009-07-01

    The chemical compositions and trace element contents (Zn, Cu, Co, Cr, Ni, Pb, Cd, As, B, Hg, Sr, Se, Be, Ba, Mn, Th, V, U) in coal and coal ash samples from Tamnava-Zapadno Polje coal field in Serbia were studied. The coal from this field belongs to lignite. This high volatility coal has high moisture and low S contents, moderate ash yield, and high calorific value. The coal ash is abundant in alumosilicates. Many trace elements such as Ni > Cd > Cr > B > As > Cu > Co > Pb > V > Zn > Mn in the coal and Ni > Cr > As > B > Cu > Co = Pb > V > Zn > Mn in the coal ash are enriched in comparison with Clarke concentrations.

  6. Explorating coupled production of dissolved organic material and methyl mercury in a tidal wetland using the intrinsic chemical composition of the organic material

    NASA Astrophysics Data System (ADS)

    Bergamaschi, B. A.; Fleck, J. A.; Downing, B.; Stephenson, M.; Hernes, P. J.; Boss, E.

    2007-12-01

    Elevated methyl mercury (MeHg) levels found in biota of the San Francisco Estuary have been attributed to methylation processes in the peat-rich tidal wetlands of the Estuary, where the concentration of dissolved organic matter (DOM) is tightly coupled to that of MeHg (r2=0.95). We sought to understand the geochemical processes that contribute to MeHg production by examining the composition of the co-occurring DOM. We measured spectral absorbance and fluorescence properties of DOM, as well as intrinsic chemical properties such as isotopic composition, lignin content, carbohydrate content, and bulk chemical functionality (by CPMAS-NMR). Carbon quality parameters independent of concentration such as specific UV absorbance, lignin abundance, aromatic content, biodegradability, and others were closely coupled to MeHg concentrations. This coupling, combined with the hydrologic forcing within the wetland, suggest that the zones of MeHg production are biogeochemically related to the zones of DOM release, thus providing a means to examine the underlying processes. The observed relationships were robust through the winter, spring, and fall seasons, despite a three- fold variation in MeHg and DOM concentration. The pattern of variation suggests sources of DOM and MeHg within peat pore waters rather than within the litter layer or water column. The various relationships with individual parameters will be discussed.

  7. Fatigue Crack Measurement in Composite Materials by Ultrasonic Methods

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Russell, Samuel S.; Suits, Michael W.; Workman, Gary L.; Watson, Jason M.; Thom, Robert (Technical Monitor)

    2002-01-01

    The nondestructive detection of intra-ply microcracking in unlined pressure vessels fabricated from composite materials is critical to ensuring mission success. Microcracking in composite structures due to combined fatigue and cryogenic thermal loading can be very troublesome to detect in-service and when it begins to link through the thickness can cause leakage and failure of the structure. These leaks may lead to loss of pressure/propellant, increased risk of explosion and possible cryo-pumping. The work presented herein develops a method and an instrument to locate and measure intraply fatigue cracking through the thickness of laminated composite material by means of correlation with ultrasonic resonance. Resonant ultrasound spectroscopy provides measurements which are, sensitive to both the microscopic and macroscopic properties of an object. Elastic moduli, acoustic attenuation, and geometry can all be probed. The approach is based on the premise of half-wavelength resonance. The method injects a broadband ultrasonic wave into the test structure using a swept frequency technique. This method provides dramatically increased energy input into the test article, as compared to conventional spike pulsed ultrasonics. This relative energy increase improves the ability to measure finer details in the materials character, such as micro-cracking and porosity. As the micro-crack density increases, more interactions occur with the higher frequency (small wavelength) components of the signal train causing the spectrum to shift toward lower frequencies. Preliminary experiments have verified a measurable effect on the resonance spectrum of the ultrasonic data to detect microcracking. Methods involving self organizing neural networks and other clustering algorithms show that the resonance ultrasound signatures from composites vary with the degree of microcracking and can be separated and identified.

  8. Characterization of the chemical composition of polyisobutylene-based oil-soluble dispersants by fluorescence.

    PubMed

    Pirouz, Solmaz; Wang, Yulin; Chong, J Michael; Duhamel, Jean

    2014-04-10

    A novel methodology based on fluorescence quenching measurements is introduced to determine quantitatively the amine content of polyisobutylene succinimide (PIBSI) dispersants used as engine oil-additives. To this end, a series of five PIBSI dispersants were prepared by reacting 2 mol equiv of polyisobutylene succinic anhydride (PIBSA) with 1 mol equiv of hexamethylenediamine (HMDA), diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine to yield the corresponding b-PIBSI dispersants. After having demonstrated that the presence of hydrogen bonds between the polyamine linker and the succinimide carbonyls of the dispersants prevents the quantitative analysis of the (1)H NMR and FTIR spectra of the dispersants to determine their chemical composition, alternative procedures based on gel permeation chromatography (GPC) and fluorescence quenching were implemented to estimate the amine content of the b-PIBSI dispersants. Taking advantage of the doubling in size that occurs when 2 mol of PIBSA are reacted with 1 mol of HMDA, a combination of GPC and FTIR was employed to follow how the chemical composition and molecular weight distribution of the polymers produced evolved with the reaction of PIBSA and HMDA mixed at different molar ratios. These experiments provided the PIBSA-to-HMDA molar ratio yielding the largest b-PIBSI dispersants and this molar ratio was then selected to prepare the four other dispersants. Having prepared five b-PIBSI dispersants with well-defined secondary amine content, the fluorescence of the succinimide groups was found to decrease with increasing number of secondary amines present in the polyamine linker. This result suggests that fluorescence quenching provides a valid method to determine the chemical composition of b-PIBSI dispersants which is otherwise difficult to characterize by standard (1)H NMR and FTIR spectroscopies. PMID:24628080

  9. Microstructure and properties of multiphase and functionally graded materials prepared by chemical vapor deposition

    SciTech Connect

    Lee, W.Y.

    1996-05-01

    The synthesis of multiphase and functionally graded materials by chemical vapor deposition is discussed from a perspective of controlling their composition and microstructure at a nano-scale level, and ultimately, tailoring their material properties. Prior research is briefly reviewed to address the current state of this novel material concept. Recent experimental results relating to controlling the selected properties of two multiphase systems, TiN + MoS{sub 2} and NiAl + Al{sub 2}O{sub 3}, are described to illustrate this concept`s potential merits and challenges for use in realistic applications.

  10. Self-healing structural composite materials

    Microsoft Academic Search

    M. R. Kessler; N. R. Sottos; S. R. White

    2003-01-01

    A self-healing fiber-reinforced structural polymer matrix composite material is demonstrated. In the composite, a microencapsulated healing agent and a solid chemical catalyst are dispersed within the polymer matrix phase. Healing is triggered by crack propagation through the microcapsules, which then release the healing agent into the crack plane. Subsequent exposure of the healing agent to the chemical catalyst initiates polymerization

  11. Recycling By Solvolysis Thermosetting Composite Materials Of Sustainable Surface Transport

    SciTech Connect

    Oliveux, Geraldine; Le Gal La Salle, Eric [Laboratoire de Thermocinetique de Nantes (LTN), UMR CNRS 6607, Ecole Polytechnique de l'Universite de Nantes, Rue Christian Pauc, 44303 Nantes (France); Bailleul, Jean-Luc [Laboratoire Energetique, Mecanique et Materiaux(LE2M) de l'Institut Catholique des Arts et Metiers de Nantes, 35 avenue du champ de Manoeuvres, 44470 Carquefou (France)

    2011-01-17

    A solvolysis process is studied to degrade an unsaturated polyester resin based on DCPD (dicyclopentadiene) and crosslinked with styrene, as the matrix of a composite material reinforced with long glass fibers. The study presented here investigates in particular the hydrolysis in conditions below the critical point of water (T<374 deg. C and P<221bar) in a batch reactor. Process window and parameter influences were studied by a Design of Experiments (DOE) approach (1). A tar-like substance issued from thermal degradations is formed in greater or lesser quantities depending on the operating conditions, and coats the fibers. The appearance of the composite samples and the degree of conversion for the degradation at 250 deg. C lead us to make a parallel with osmosis phenomena to explain the initiation mechanism of the degradation.

  12. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1987-01-01

    The development and application of composite materials to aerospace vehicle structures which began in the mid 1960's has now progressed to the point where what can be considered entire airframes are being designed and built using composites. Issues related to the fabrication of non-resin matrix composites and the micro, mezzo and macromechanics of thermoplastic and metal matrix composites are emphasized. Several research efforts are presented. They are entitled: (1) The effects of chemical vapor deposition and thermal treatments on the properties of pitch-based carbon fiber; (2) Inelastic deformation of metal matrix laminates; (3) Analysis of fatigue damage in fibrous MMC laminates; (4) Delamination fracture toughness in thermoplastic matrix composites; (5) Numerical investigation of the microhardness of composite fracture; and (6) General beam theory for composite structures.

  13. HPTLC determination of chemical composition variability in raw materials used in botanicals.

    PubMed

    Toniolo, Chiara; Nicoletti, Marcello; Maggi, Filippo; Venditti, Alessandro

    2014-01-01

    Besides the chemotaxonomic value, nowadays determination of biodiversity and chemical variability has a commercial impact. The exact identity of raw material and constituents of botanical products, such as food supplements or herbal remedies, is a very important argument, being the real prerequisite for quality control and traceability, followed by the determination of active components. However, the analytical approach must consider the natural great variability in secondary metabolites and product form, such as in extracts. Against the reductive approach, on the basis of single chemical standards, so far dominant in Pharmacopoeias monographs, we report applications and utility of the high-performance thin-layer chromatography fingerprint in determination of species of the same genus, of populations of the same species and of different drugs of the same plant. PMID:24219430

  14. Chemical Composition and Fatty Acid Content of Some Spices and Herbs under Saudi Arabia Conditions

    PubMed Central

    Al-Jasass, Fahad Mohammed; Al-Jasser, Mohammed Saud

    2012-01-01

    Some Saudi herbs and spices were analyzed. The results indicated that mustard, black cumin, and cress seeds contain high amount of fat 38.45%, 31.95% and 23.19%, respectively, as compared to clove (16.63%), black pepper (5.34%) and fenugreek (4.51%) seeds. Cress, mustard, black cumin and black pepper contain higher protein contents ranging from 26.61 to 25.45%, as compared to fenugreek (12.91%) and clove (6.9%). Crude fiber and ash content ranged from 6.36 to 23.6% and from 3.57 to 7.1%, respectively. All seeds contain high levels of potassium (ranging from 383 to 823?mg/100g), followed by calcium (ranging from 75 to 270?mg/100g), Magnesium (ranged from 42 to 102?mg/100g) and iron (ranged from 20.5 to 65?mg/100g). However, zinc, manganese and copper were found at low levels. The major fatty acids in cress and mustard were linolenic acid (48.43%) and erucic acid (29.81%), respectively. The lenoleic acid was the major fatty acid in black cumin, fenugreek, black pepper and clove oils being 68.07%, 34.85%, 33.03% and 44.73%, respectively. Total unsaturated fatty acids were 83.24, 95.62, 86.46, 92.99, 81.34 and 87.82% for cress, mustard, black cumin, fenugreek, black pepper and clove, respectively. The differences in the results obtained are due to environmental factors, production areas, cultivars used to produce seeds and also due to the different methods used to prepare these local spices. PMID:23319888

  15. Chemical composition and fatty acid content of some spices and herbs under Saudi Arabia conditions.

    PubMed

    Al-Jasass, Fahad Mohammed; Al-Jasser, Mohammed Saud

    2012-01-01

    Some Saudi herbs and spices were analyzed. The results indicated that mustard, black cumin, and cress seeds contain high amount of fat 38.45%, 31.95% and 23.19%, respectively, as compared to clove (16.63%), black pepper (5.34%) and fenugreek (4.51%) seeds. Cress, mustard, black cumin and black pepper contain higher protein contents ranging from 26.61 to 25.45%, as compared to fenugreek (12.91%) and clove (6.9%). Crude fiber and ash content ranged from 6.36 to 23.6% and from 3.57 to 7.1%, respectively. All seeds contain high levels of potassium (ranging from 383 to 823 ?mg/100 g), followed by calcium (ranging from 75 to 270 ?mg/100 g), Magnesium (ranged from 42 to 102 ?mg/100 g) and iron (ranged from 20.5 to 65 ?mg/100 g). However, zinc, manganese and copper were found at low levels. The major fatty acids in cress and mustard were linolenic acid (48.43%) and erucic acid (29.81%), respectively. The lenoleic acid was the major fatty acid in black cumin, fenugreek, black pepper and clove oils being 68.07%, 34.85%, 33.03% and 44.73%, respectively. Total unsaturated fatty acids were 83.24, 95.62, 86.46, 92.99, 81.34 and 87.82% for cress, mustard, black cumin, fenugreek, black pepper and clove, respectively. The differences in the results obtained are due to environmental factors, production areas, cultivars used to produce seeds and also due to the different methods used to prepare these local spices. PMID:23319888

  16. Chemical composition of organic matter in extremely acid, lignite-containing lake sediments impacted by fly ash contamination.

    PubMed

    Chabbi, A; Rumpel, C

    2004-01-01

    In the Lusatian lignite mining district of eastern Germany, extremely acid lakes developed during ground water rising after exploitation of lignite in open-cast mines. The reasons of plant colonization (Juncus bulbosus L.) of some lakes exhibiting moderate pH values while others remain extremely acid and unvegetated are unknown. Alkalinity gain may be achieved by addition of alkaline materials and/or decomposition of organic matter. Our objective was to examine fly ash deposition and the resulting changes in organic matter composition in the uppermost 0 to 5 cm of the sediment sampled from vegetated and unvegetated lakes. Bulk soil and particle size fractions were analyzed for elemental composition, magnetic susceptibility, and chemical structure of the organic matter by 13C solid-state nuclear magnetic resonance (NMR) spectroscopy. The lignite content of the samples was estimated by 14C activity measurements. The pH values decreased with increasing depth and the changes in pH were found to be correlated with changes in magnetic susceptibility. Carbon and nitrogen contents were found to decrease with increasing depth. The C to N ratios are consistent with the (i) the presence of decomposing plant residues and/or microbial material such as algae in the upper 0 to 5 cm of the sediment and (ii) the dominance of lignite in the layers below this depth as confirmed by 14C activity measurements. The structural analyses of the particle size separates from the 0- to 5-cm depth were consistent with the presence of organic matter derived from plant material. This study confirms that fly ash is an important source of alkalinity in the upper 0 to 5 cm of the sediment that enhanced plant growth and led to enrichment of the sediment with organic matter derived from plant material. PMID:15074815

  17. Synthesis of steel slag ceramics: chemical composition and crystalline phases of raw materials

    NASA Astrophysics Data System (ADS)

    Zhao, Li-hua; Wei, Wei; Bai, Hao; Zhang, Xu; Cang, Da-qiang

    2015-03-01

    Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO-Al2O3-SiO2 and CaO-MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite, ?-quartz, magnetite, and pyroxene crystals (augite and diopside) in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA) results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag.

  18. Combinatorial approach for ferroelectric material libraries prepared by liquid source misted chemical deposition method

    PubMed Central

    Kim, Ki Woong; Jeon, Min Ku; Oh, Kwang Seok; Kim, Tai Suk; Kim, Yun Seok; Woo, Seong Ihl

    2007-01-01

    Combinatorial approach for discovering novel functional materials in the huge diversity of chemical composition and processing conditions has become more important for breakthrough in thin film electronic and energy-conversion devices. The efficiency of combinatorial method depends on the preparation of a reliable high-density composition thin-film library. The physico-chemical properties of each sample on the library should be similar to those of the corresponding samples prepared by one-by-one conventional methods. We successfully developed the combinatorial liquid source misted chemical deposition (LSMCD) method and demonstrated its validity in screening the chemical composition of Bi3.75LaxCe0.25-xTi3O12 (BLCT) for high remanent polarization (Pr). LSMCD is a cheap promising combinatorial screening tool. It can control the composition up to ppm level and produce homogeneous multicomponent library. LSMCD method allows us to prepare BLCT thin-film library at the variation of 0.4 mol% of La. Maximum 2Pr is 35 ?C/cm?2 at x = 0.21. The intensity of (117) XRD peak is quantitatively related to 2Pr. Newly developed scanning piezoelectric deformation measurement for nano-sized samples using scanning probe microscope (SPM) is also found out to be reliable for determining the relative ranking of Pr value rapidly. PMID:17218453

  19. Inversion of vegetation biochemical material contents by remote sensing

    NASA Astrophysics Data System (ADS)

    Ji, Haiyan; Wang, Pengxin; Yan, Tailai

    2006-01-01

    With remote sensing techniques, we could relate remote sensing measurements to the biochemical characteristics of the Earth surfaces in a reliable and operational way. It plays an important role in the estimate of the biochemical contents. The spectroscopic estimation of vegetation biochemical concentration was welcoming a new dawn with the developments of high spectral remote sensing technologies. Leafs of wheat at different grow period were used to measure reflectance spectra and biochemical components concentration. Reflectance spectra of leaf were measured by ASD field spectrometer in the spectra range of 350nm ~ 1650nm. Two kinds of statistical methods were used to inversion the biochemical concentrations: Stepwise regression analysis and partial least-squares regression, which were applied to established models of biochemical components concentrations (chlorophyll and water) with reflectance spectra of wheat's leaf at different grow period. The inversion results of two methods are: For chlorophyll, the correlation coefficient is 0.894, 0.898, and the relative standard deviation is 13.8%, 13.6% respectively; For water, the correlation coefficient is 0.983, 0.999, and the relative standard deviation is 2.3%, 0.3% respectively. Stepwise regression analysis method and partial least-squares regression method may inversion the chlorophyll and water of wheat leaf at different grow periods.

  20. Impact damage detection of composite materials by fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Djinovic, Zoran; Scheerer, Michael; Tomic, Milos

    2011-06-01

    Usage of fiber-optic Bragg gratings (FBG) for strain measurement is well-known technique in structural health monitoring (SHM). However, this technique based on shift of spectral peak, suffers from different spurious signals, particularly caused by thermal effect. We present here a method for impact damage detection of composite materials based on FBG without thermal disturbance. This method is based on the broadening of the spectral peak in dependence on the FBG separation from the impact damage. We used a sensing configuration where an Optical Spectrum Analyzer was interrogated with an array of 10 FBGs with central wavelength between 812 and 817nm that were bonded on a CFRP composite plate with 8 plies. We performed two groups of impact experiments: by impact energy of about 10J and 20J. We found there was no any significant shift of the spectral peak after the impact. Contrary, we confirmed in the last experiments the spectral peak broadening caused by impact load. The spectrum broadening primarily depends on the strain gradient generated into the FBGs, i.e. into the damaged area. We made a correlation between the peak width and FBG-impact damage separation. There are three characteristic regions; near to impact, abrupt region and almost even region.

  1. Treatment of chemical warfare agents by zero-valent iron nanoparticles and ferrate(VI)\\/(III) composite

    Microsoft Academic Search

    Radek Zboril; Marek Andrle; Frantisek Oplustil; Libor Machala; Jiri Tucek; Jan Filip; Zdenek Marusak; Virender K. Sharma

    Nanoscale zero-valent iron (nZVI) particles and a composite containing a mixture of ferrate(VI) and ferrate(III) were prepared by thermal procedures. The phase compositions, valence states of iron, and particle sizes of iron-bearing compounds were determined by combination of X-ray powder diffraction, Mössbauer spectroscopy and scanning electron microscopy. The applicability of these environmentally friendly iron based materials in treatment of chemical

  2. Regulating continent growth and composition by chemical weathering

    PubMed Central

    Lee, Cin-Ty Aeolus; Morton, Douglas M.; Little, Mark G.; Kistler, Ronald; Horodyskyj, Ulyana N.; Leeman, William P.; Agranier, Arnaud

    2008-01-01

    Continents ride high above the ocean floor because they are underlain by thick, low-density, Si-rich, and Mg-poor crust. However, the parental magmas of continents were basaltic, which means they must have lost Mg relative to Si during their maturation into continents. Igneous differentiation followed by lower crustal delamination and chemical weathering followed by subduction recycling are possible solutions, but the relative magnitudes of each process have never been quantitatively constrained because of the lack of appropriate data. Here, we show that the relative contributions of these processes can be obtained by simultaneous examination of Mg and Li (an analog for Mg) on the regional and global scales in arcs, delaminated lower crust, and river waters. At least 20% of Mg is lost from continents by weathering, which translates into >20% of continental mass lost by weathering (40% by delamination). Chemical weathering leaves behind a more Si-rich and Mg-poor crust, which is less dense and hence decreases the probability of crustal recycling by subduction. Net continental growth is thus modulated by chemical weathering and likely influenced by secular changes in weathering mechanisms. PMID:18362343

  3. Chemical Composition by the APXS along the Downhill Traverse of the Mars Exploration Rover Spirit at Gusev Crater

    NASA Astrophysics Data System (ADS)

    Brueckner, J.; Dreibus, G.; Gellert, R.; Clark, B. C.; Cohen, B.; McCoy, T.; Ming, D. W.; Mittlefehldt, D. W.; Yen, A.; Team, A. S.

    2006-12-01

    The Alpha Particle X-ray Spectrometer (APXS) onboard the Mars Exploration Rover Spirit continues to determine the elemental composition of samples at Gusev Crater. Starting around sol 600 the rover descended Husband Hill, which is part of the Columbia Hills, visited the inner basin with a large dune field, called `El Dorado', and parked at `Low Ridge' to conserve energy during the martian winter. Many unique samples were discovered by the instruments onboard Spirit during her downhill traverse. Here, we report only on the chemical data obtained by the APXS. The compositions of some of the soil samples are comparable to the mean soil determined along the earlier traverse. However, a light-toned subsurface sample (disturbed by the rover wheels), called `Dead Sea Samra', showed the highest sulfur content of all soil samples, the lowest Na, Mg, Al, Cl, K, Ca, Ti, Mn, and Zn, among the lowest Si and P, and among the highest Cr, Fe and Ni. Assuming ferric sulfate as a major mineral, large amounts of a pure silica phase must be present. Color and quantity of Dead Sea Samra resemble somewhat an earlier soil called `Paso Robles', though the latter is a mixture of sulfates with phosphate-rich soil. Manganese in Dead Sea Samra is so low that the Fe/Mn ratio exceeds 300, a value that has never been found previously on Mars (Fe/Mn ratio of 46 for Gusev basalts), indicating that only Fe3+ occurs. The dune field El Dorado contained granulated material that exhibited the highest Mg and Ni concentrations and the lowest S and Cl compared to all other soils implying an enrichment of olivine-rich sands. Two outcrops, called `Algonquin' and `Comanche', revealed compositions that differ significantly from those of earlier outcrops as they have the highest concentrations of Mg, Fe, and Ni (except for Ni in `Independence') and the lowest of Al, K (detection limit), Ca, and Ti of all brushed and almost all abraded rocks. Normative estimates assign them the highest olivine contents ever found for martian rocks and a very mafic nature based on their high Mg/(Mg+Fe) and low Al, Ca and Na. Their significantly high Ni contents point to a different source than the Gusev plains basalts. The elemental compositions of samples encountered during the downhill traverse revealed a larger chemical diversity of the Columbia Hills than the uphill trek already published.

  4. Optical composite materials

    SciTech Connect

    Beecroft, L.L.; Ober, C.K.; Barber, D.B. [Cornell Univ., Ithaca, NY (United States)] [and others

    1995-12-31

    Optical quality composite materials can be useful for many applications. This work concerns optical quality composite films constructed from very small (<100 nm) particles of optically functional material embedded in a matrix of the same refractive index (RI). The particles impart their optical properties, while the matrix allows for processing of films. The initial optical composite studied contained Cr-forsterite (Cr-Mg{sub 2}SiO{sub 4}), a tunable solid state laser material in the attractive near-IR regime (1167-1345 nm). Small Cr-forsterite particles were synthesized by firing preceramic dispersion polymerization beads, and were embedded in unusually high RI polymeric matrix materials. Work to make optical amplification measurements is underway. This composite concept can be extended to other optically interesting materials.

  5. Use of near infrared spectroscopy for estimating meat chemical composition, quality traits and fatty acid content from cattle fed sunflower or flaxseed.

    PubMed

    Prieto, N; López-Campos, O; Aalhus, J L; Dugan, M E R; Juárez, M; Uttaro, B

    2014-10-01

    This study tested the ability of near infrared reflectance spectroscopy (NIRS) to predict meat chemical composition, quality traits and fatty acid (FA) composition from 63 steers fed sunflower or flaxseed in combination with high forage diets. NIRS calibrations, tested by cross-validation, were successful for predicting crude protein, moisture and fat content with coefficients of determination (R(2)) (RMSECV, g·100g(-1) wet matter) of 0.85 (0.48), 0.90 (0.60) and 0.86 (1.08), respectively, but were not reliable for meat quality attributes. This technology accurately predicted saturated, monounsaturated and branched FA and conjugated linoleic acid content (R(2): 0.83-0.97; RMSECV: 0.04-1.15mg·g(-1) tissue) and might be suitable for screening purposes in meat based on the content of FAs beneficial to human health such as rumenic and vaccenic acids. Further research applying NIRS to estimate meat quality attributes will require the use on-line of a fibre-optic probe on intact samples. PMID:24976561

  6. Chemical composition and mineralogy of borate from Rio Grande deposit, Uyuni (Bolivia) as raw materials for industrial applications

    NASA Astrophysics Data System (ADS)

    Guillen Vargas, Julio; Arancibia, Jony Roger Hans; Alfonso, Pura; Garcia-Valles, Maite; Parcerisa, David; Martinez, Salvador

    2014-05-01

    Bolivia has large tailings as a result of the historic and present-day Sn mining activity developed extensively in that country. Tailings produced in these mining activities have an appropriate composition to reprocess them and make silicate glass and glass-ceramics, obtaining the valorization of wastes and reducing the visual and chemical impact. Reprocessing the wastes to make glass and glass-ceramics prevents the leaching of heavy metals from those wastes because they are retained in the structure of the glass. Furthermore, an option to increase the economic value of these glasses is the introduction of boron and other additives to produce borosilicate glass. In this study a characterization of the Rio Grande borate deposit for its use in the manufacture of borosilicate glass is presented. Mineralogy was determined by X-ray diffraction (XRD), and Fourier transforms infrared spectroscopy (FTIR); textures were observed by scanning electron microscopy (SEM) and chemical composition was determined by inductively coupled plasma mass spectrometry (ICP-MS). The Rio Grande borate deposit is located in an area of about 50 km2 close to the south of the Salar of Uyuni, in the Río Grande de Lípez Delta. Borates occur in the contact between fluvio-deltaic and lacustrine sediments from water raising the surface by capillarity. The borates crop out in an extent area but towards the west they are covered by fluvio-deltaic sediments, which can be up to 2 m thick. These borates occur as lenses 50-100 m in diameter and layers up to 1 m thick. They usually form brittle nodules with a cotton-ball texture. Chemical composition of the Rio Grande borates is CaO, 11.82-13.83 wt%; Na2O, 13.50-19.35 wt%; K2O, 0.05- 1.04 wt%; MgO, 0.42-1.46 wt%; B2O3, 36.21-42.60 wt%; SiO2, up to 0.53 wt% and SO2, up to 0.60 wt%. Trace elements are low: Sr content is between 151-786 ppm, Al 12-676 ppm, Mn between 1-17 ppm, As 2-10 ppm and Fe between 9-376 ppm. The most abundant borate mineral in this deposit is ulexite (NaCaB5.5H20), halite can reach up to 17 wt% and gypsum up to 1.2 wt.%. Calcite occurs in minor contents. Ulexite exhibits a fibrous morphology with fibers oriented parallel each other. Purity of borates from the Rio Grande deposits makes them suitable for the most restrictive applications. Chemistry of these borates is in accordance with the necessary composition for obtaining borosilicate glasses. Acknowledgements: This work was partly financed by the project AECID: A3/042750/11, and the SGR 2009SGR-00444.

  7. Corrosion studies on construction materials for flue-gas-desulfurization systems. [Effects of Ph, chloride content, and alloy composition

    SciTech Connect

    Maiya, P.S.

    1982-08-01

    Several Mo- and Cr-bearing alloys of interest to flue-gas desulfurization (FGD) systems have been examined for corrosion in simulated FGD environments at 85/sup 0/C. To evaluate the importance of hydrogen and chloride ion concentrations, Type 316L stainless steel was exposed for varying times at different pH levels (0.5 to 3.0) and chloride content (0.03 to 5.0 wt% Cl/sup -/). To determine the effects of pH and composition in acid solution that contains a fixed amount of chloride (approx. 0.34 wt% Cl/sup -/), a number of alloys were used in which the composition parameter (defined as the sum of Cr and Mo) varied from 19.5 to 33.5 wt%. In all cases, the general corrosion or dissolution as determined from weight loss measurements (mg mm/sup -2/) varied linearly with time. The corrosion rate (mg mm/sup -2/ h/sup -1/) for the alloys decreased with an increase in pH in a consistent manner regardless of the alloy crystal structure. The composition effects on corrosion rate were most significant at pH = 0.5. The dependence of corrosion rate on pH, chloride ion concentration, and alloy composition is discussed in a quantitative manner. The relationships developed from the kinetic data provide useful guidance in the selection of appropriate alloys for more comprehensive studies under more realistic FGD testing environments that include environmental and stress cycling. Also, the materials evaluation approach adopted in the present study enables predictions of the life of components subjected to different environments and is relevant to alloy development work in progress elsewhere. In addition, testing and evaluation procedures have been developed for two alternative materials, namely, a fiber-reinforced plastic (Atlac 4010-A from ICI Americas, Inc.) and an epoxy coating on mild steel (Markote 300 System from Martek Engineering, Inc.); preliminary results are presented.

  8. Strength of composite materials

    Microsoft Academic Search

    F. F. Egorov; P. S. Kislyi; P. A. Verkhovodov

    1979-01-01

    1.A study was made of the strength of ZrN-Al2O3 composite materials produced by solid- and liquid-phase sintering in argon and nitrogen. It is shown that the strength of composites sintered in nitrogen is such less than that of composites sintered in argon, which is linked with the formation of new phases at boundaries between dissimilar phases and with a weakening

  9. Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods - slides

    EPA Science Inventory

    Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

  10. Comparison of Chemical Composition of Complex Disinfection Byproduct (DBP) Mixtures Produced by Different Treatment Methods

    EPA Science Inventory

    Analyses of the chemical composition of complex DBP mixtures, produced by different drinking water treatment processes, are essential to generate toxicity data required for assessing their risks to humans. For mixture risk assessments, whole mixture toxicology studies generally a...

  11. Influence of Sb content on electromagnetic properties of ATO/ferrite composites synthesized by co-precipitation method

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Wang, Lixi; Zhang, Qitu

    2015-09-01

    Composite microwave absorbers based on ATO (antimony-doped tin oxide) and W-type ferrite were prepared by a co-precipitation method, and the effects of Sb content on electromagnetic properties and reflection loss characteristics were studied in 2-18 GHz. The prepared composite particles were characterized with X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The results showed that the nano-particles ATO were coated with the surface of hexagonal flake ferrite, and with the increase of Sb content, the grain size of ATO nano-particles decreases resulting in agglomeration. The complex permittivity and permeability of the ferrite/ATO composites were analyzed by a vector network analyzer (Agilent E5071C), and the reflection loss was simulated by software YRComputer. The dielectric loss mainly comes from ATO, with the increase of Sb content, the real and imaginary parts of permittivity of the composites increase first, then decrease; The interface effects and surface effects lead to the increase of imaginary part ?? of the absorbing materials in the macro; When the mole ratio of Sb/Sn is 2:10, the reflection loss reaches the maximum value -43.07 dB at 10.64 GHz for a layer 2.8 mm, and the bandwidth over an absorptivity of 90% (-10 dB reflection loss) is 8.32 GHz (ranging from 7.12 GHz to 15.44 GHz).

  12. Chemometric Survey of Italian Bottled Mineral Waters by Means of their Labelled Physicochemical and Chemical Composition

    Microsoft Academic Search

    Andrea Versari; Giuseppina Paola Parpinello; Sergio Galassi

    2002-01-01

    Bottled mineral waters (132 samples) from 19 districts of Italy were characterized by means of the physico-chemical and chemical composition (30 parameters) reported on their label by using statistical analysis. Bottled waters showed a lack of homogeneity in the type of parameters reported in the label, the level of aluminium being reported by only five brands. The relationships among 12

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    The promise of filamentary composite materials, whose development may be considered as entering its second generation, continues to generate intense interest and applications activity. Fiber reinforced composite materials offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been achieved since the initial developments in the mid 1960's. Rather limited applications to primary aircraft structure have been made, however, mainly in a material-substitution mode on military aircraft, except for a few experiments currently underway on large passenger airplanes in commercial operation. To fulfill the promise of composite materials completely requires a strong technology base. NASA and AFOSR recognize the present state of the art to be such that to fully exploit composites in sophisticated aerospace structures, the technology base must be improved. This, in turn, calls for expanding fundamental knowledge and the means by which it can be successfully applied in design and manufacture.

  14. Changes in chemical composition, physical properties and microstructure of duck egg as influenced by salting

    Microsoft Academic Search

    Thammarat Kaewmanee; Soottawat Benjakul; Wonnop Visessanguan

    2009-01-01

    Changes in chemical composition, physical properties and microstructure of duck egg, during salting for up to 14 days, were determined. Duck egg consisted of 10.87% shell, 54.73% egg white and 33.94% yolk. Salting resulted in an increase in weight proportion of egg white, but a decrease in yolk proportion. Moisture contents of both egg white and yolk decreased gradually with

  15. New wear resistant composite material

    SciTech Connect

    Angers, R.; Champagne, B.; Fiset, M.; Chollet, P.

    1983-01-01

    A composite material consisting of WC-Co particles in a steel matrix was fabricated by sintering mixtures of WC-Co particles and a steel powder and infiltrating the sintered pieces with a copper alloy. Its wear resistance and mechanical properties were studied as a function of the content in WC-Co particles and other characteristics of the composite material microstructure. Infiltration provided a simple means to obtain a strong cohesion between WC-Co particles and the steel matrix. An effective matrix protection against wear is obtained with relatively low additions of particles especially with a silica abrasive which is soft with respect to cemented carbide. The experimental results show that this material has good mechanical properties and wear resistance. Depending upon abrasion resistance, wear losses are reduced up to 10 times by a 30 vol% addition of cemented carbide particles.

  16. Composite Materials Handbook

    NSDL National Science Digital Library

    From the US Army Research Laboratory, Materials Sciences Corporation, and University of Delaware Center for Composite Materials, the Composite Materials Handbook provides the "information and guidance necessary to design and fabricate end items from composite materials." Along with current information on the material properties of these composite materials, the handbook also includes data development and usage guidelines. The information has been divided into three areas: polymer, metal, and ceramic matrix composites. The Polymer Matrix Composites Handbook (three volumes including Guidelines for Characterization of Structural Materials; Material Properties; and Materials Usage, Design, and Analysis) and the Metal Matrix Composites Handbook (one volume, .pdf) are available here. The Ceramic Matrix Composites Handbook has yet to be completed. Users may also download Quick Composites Data in spreadsheet format.

  17. Effects of coal rank on the chemical composition and toxicological activity of coal liquefaction materials

    SciTech Connect

    Wright, C.W.; Dauble, D.D.

    1986-05-01

    This report presents data from the chemical analysis and toxicological testing of coal liquefaction materials from the EDS and H-Coal processes operated using different ranks of coal. Samples of recycle solvent from the bottoms recycle mode of the EDS direct coal liquefaction process derived from bituminous, sub-bituminous, and lignite coals were analyzed. In addition, the H-Coal heavy fuel oils derived from bituminous and sub-bituminous coals were analyzed. Chemical methods of analysis included adsoprtion column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, and low-voltage probe-inlet mass spectrometry. The toxicological activity of selected samples was evaluated using the standard microbial mutagenicity assay, an initiation/promotion assay for mouse-skin tumorigenicity, and a static bioassy with Daphnia magna for aquatic toxicity of the water-soluble fractions. 22 refs., 16 figs., 14 tabs.

  18. Computing Equilibrium Chemical Compositions

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

    Chemical Equilibrium With Transport Properties, 1993 (CET93) computer program provides data on chemical-equilibrium compositions. Aids calculation of thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93/PC is version of CET93 specifically designed to run within 640K memory limit of MS-DOS operating system. CET93/PC written in FORTRAN.

  19. [Studies on the changes in rice straw composition in relay treatment of chemical-microbial process by FTIR spectroscopy].

    PubMed

    Xu, Yong; Shen, Qi-rong; Zhong, Zeng-tao; Chen, Xiang-huai

    2004-09-01

    Direct burning of crop straw in the field has given or is giving rise to a serious pollution of atmosphere. The difficult decomposing of the crop straw by soil microorganisms is one of the reasons the crop straw is not popularly used in agriculture. Fourier transform infrared spectroscopy (FTIR) was used to study the changes in straw composition during the relay treatment of chemical-microbial process. The results showed that the method of FTIR spectra could indicate the changes in straw composition during the treatment processes. After the relay treatment of chemical-microbial process, the contents of cellulose, semi-cellulose, and silicon, and C/N ratio were decreased significantly, while the water soluble substances were increased, which was in accordance with the results of chemical analysis. The method to treat crop straw proposed in this paper could provide a practicable way in agricultural utilization of crop straw. PMID:15762520

  20. Making ceramic- metal composite material by friction stir processing

    NASA Astrophysics Data System (ADS)

    Govindaraju, M.; Balasubramanian, K.; Chakkingal, Uday; Prasad Rao, K.

    2015-02-01

    An innovative method to add ceramic particles in the metal matrix to make ceramic metal matrix composite was experimented and proved with alumina powder as particles and AE42 magnesium alloy as matrix. The alloy was subjected to friction stir processing and alumina particles were added through the processing tool. AE42 magnesium alloy has primary ?-Mg phase of 100-150 micron grain size and secondary phase of 10-50 micron size as precipitates. Al2RE, Al11RE3 and Al17Mg12 are main secondary phases in the form of precipitates. Alumina powder was selected with average particles size of 5 micron. For processing parameters of 300-400 rpm tool speed, 15-20 mm/minute traverse speed and a threaded pin geometry; composites with fine distribution of second phase precipitates and alumina particles in the matrix were observed. Mechanical and microstructural characterization revealed uniform properties in longitudinal and transverse directions. Composite material has superior mechanical properties than the magnesium alloy. Distribution of particles was up to the length of tool pin. Tool pin geometry, feed rate and volume percentage of alumina particles, processing speed and tool rpm on the effect of mechanical and micro-structural properties were analyzed in detail.

  1. Updated estimates of the selenomethionine content of NIST wheat reference materials by GC-IDMS.

    PubMed

    Wolf, Wayne R; Goldschmidt, Robert J

    2007-04-01

    Updated estimates of the selenomethionine content of four NIST wheat reference materials have been obtained by use of a revised gas chromatography-stable-isotope dilution mass spectrometric method. The revised method makes use of digestion with methanesulfonic acid, which enables more complete recovery of endogenous selenomethionine than was previously achieved by overnight denaturing treatment in 0.1 mol L(-1) HCl. The NIST wheat reference materials each contain approximately 55% of their total Se content as selenomethionine. Information about forms of Se in reference materials adds value to these materials in Se speciation studies. Estimates of selenomethionine content are also provided for other wheat samples, including several grown under conditions of exposure to high Se levels. These samples also contain approximately 55% of their total Se content as selenomethionine. The consistent level of 55% of total selenium occurring in the form of selenomethionine when the total selenium content varies by a factor of 500 is suggestive of an active mechanism of incorporation of selenium into wheat grain. Figure Selenomethionine content of wheat samples. PMID:17123069

  2. Light energy transmission through composite influenced by material shades.

    PubMed

    Guiraldo, Ricardo Danil; Consani, Simonides; Consani, Rafael Leonardo Xediek; Berger, Sandrine Bittencourt; Mendes, Wilson Batista; Sinhoreti, Mario Alexandre Coelho

    2009-01-01

    This study investigated the influence of different composite resin shades on light energy transmission through the composite, hardness and cross-link density (CLD). The composite Filtek Z250 was used in shades A1, A2, A3, A3.5 and A4. A quartz tungsten halogen light curing unit was used at an irradiance of 900 mW/cm(2). Thirty specimens were made for each shade. Light energy transmission that passed through the composite was calculated (n=10). Differences in Knoop hardness between the top and bottom (DKH) of the same specimen were calculated (n=10). The Knoop hardness value for each surface was recorded as the average of three indentations (KHN(1)). Thereafter, the specimens were soaked in absolute ethanol for 24hr at room temperature, and hardness was again determined (KHN(2)). The CLD was estimated by the softening effect produced by ethanol, i.e., by decrease in hardness. The percentage of decrease in KHN(2) compared with KHN(1) (PD) in the same specimen was then calculated for both surfaces (n=10). The data were submitted to an ANOVA in different tests (Light energy transmission, Knoop hardness and CLD). The irradiance of light that passed through composite shade A1 (408 mW/cm(2)) was statistically greater than that through shade A2 (376 mW/cm(2)), and was greater through A2 than A3 (359 mW/cm(2)) and through A3 than A3.5 (327 mW/cm(2)); A3.5 showed no statistical difference when compared to A4 (324 mW/cm(2)). The DKH of A4 (20.56%) was not statistically higher than that of A3.5 (20.14%), which was greater than that of A3 (14.08%), A2 (11.65%) and A1 (9.06%). There was no statistical difference in CLD. Darker shades had a significant influence on light energy transmission through dental resin composite and its hardness. However, CLD was not affected by darker dental composite shades. PMID:20179393

  3. CHAPTER XVII CHEMICAL COMPOSITION

    E-print Network

    CHAPTER XVII CHEMICAL COMPOSITION PfJ#e Proximate composition of oyster meat._ 381 Seasonal_________ ___ __ _ _____________ ____ ____ ___________ _______ 383 Heavy metals__ _ _ __ __ ___ __ 383 Observations on New England oysters of magnitude of the three components is common to all the speeies studied. The proteins make up 50 percent

  4. Chemical composition of the rhizomes of the Rhodiola rosea by the HPLC method

    Microsoft Academic Search

    A. G. Dubichev; V. A. Kurkin; G. G. Zapesochnaya; E. D. Vorontsov

    1991-01-01

    The component composition of extracts of the rhizomes ofRhodiola rosea has been studied by the HPLC method; the amount of rosavin has been determined and its lability on the autofermention of the raw material has been established.

  5. Chemical recycling of scrap composites

    NASA Technical Reports Server (NTRS)

    Allred, Ronald E.; Salas, Richard M.

    1994-01-01

    There are no well-developed technologies for recycling composite materials other than grinding to produce fillers. New approaches are needed to reclaim these valuable resources. Chemical or tertiary recycling, conversion of polymers into low molecular weight hydrocarbons for reuse as chemicals or fuels, is emerging as the most practical means for obtaining value from waste plastics and composites. Adherent Technologies is exploring a low-temperature catalytic process for recycling plastics and composites. Laboratory results show that all types of plastics, thermosets as well as thermoplastics, can be converted in high yields to valuable hydrocarbon products. This novel catalytic process runs at 200 C, conversion times are rapid, the process is closed and, thus, nonpolluting, and no highly toxic gas or liquid products have been observed so no negative environmental impact will result from its implementation. Tests on reclamation of composite materials show that epoxy, imide, and engineering thermoplastic matrices can be converted to low molecular weight hydrocarbons leaving behind the reinforcing fibers for reuse as composite reinforcements in secondary, lower-performance applications. Chemical recycling is also a means to dispose of sensitive or classified organic materials without incineration and provides a means to eliminate or reduce mixed hazardous wastes containing organic materials.

  6. [Chemical composition analysis of early neolithic pottery unearthed from Xiaohuangshang site, Zhejiang Province and Jiahu site, Henan Province by energy disperse X-ray fluorescence].

    PubMed

    Chen, Qian-Qian; Yang, Yu-Zhang; Zhang, Ju-Zhong; Cui, Wei

    2011-11-01

    The major elements in the early neolithic potteries unearthed from Xiaohuangshan site, Zhejiang Province and Jiahu site, Henan Province were determined by energy disperse X-ray fluorescence (EDXRF). The results show that the chemical compositions of the potteries from these two sites possess obvious regional features respectively. Compared with the specimen from Jiahu site, the potteries from Xiaohuangshan site have the common feature of ancient Chinese southern ceramics with high silicon and low aluminum contents. Simultaneously, the chemical composition of Xiaohuangshan pottery samples nearly unchanged from its early stage to the last stage. This phenomenon indicates that the source of the ceramic raw materials of Xiaohuangshan site was stable, and the continuous improvement of its pottery quality was mainly due to the progress in sintering techniques. However, the chemical composition of Jiahu potteries changed a lot in its three different periods. This change occurred because a large number of admixtures were added to the pottery bodies to improve their operating performances. These results also show that the improvements of pottery making techniques in different Chinese areas may have their own evolution directions respectively for the different geographical environments. PMID:22242535

  7. Average chemical composition of the lunar surface

    NASA Technical Reports Server (NTRS)

    Turkevich, A. L.

    1973-01-01

    The available data on the chemical composition of the lunar surface at eleven sites (3 Surveyor, 5 Apollo and 3 Luna) are used to estimate the amounts of principal chemical elements (those present in more than about 0.5% by atom) in average lunar surface material. The terrae of the moon differ from the maria in having much less iron and titanium and appreciably more aluminum and calcium.

  8. Study of dielectric relaxation spectra of composite materials by the dielectric spectroscopy method

    Microsoft Academic Search

    O. S. Gefle; S. M. Lebedev; Y. P. Pokholkov; S. N. Tkachenko; V. A. Volokhin; E. I. Cherkashina

    2005-01-01

    In this paper composite solid dielectrics were studied by using the dielectric spectroscopy method in frequency domain. Dielectric relaxation spectra of composite materials on the basis of natural and synthetic rubbers and LDPE filled with a ferroelectric ceramic powder PZT (lead zirconate titanate) were studied. The filled composites with high permittivity were used in HV insulation for the electric field

  9. Permeation of glove materials by physiologically harmful chemicals

    Microsoft Academic Search

    JOHN R. WILLIAMS

    1979-01-01

    The breakthrough times and permeation rates of 1,4-dichloro-2-butene, benzene, carbon tetrachloride, and 2-chloro-1,3-butadiene for eleven commercially available gloves were determined. Four methods of determining the breakthrough time and permeation rate were evaluated. A wide variation in the glove material thickness and protection time was found showing that the adequate protection time can only be determined by testing the proposed glove

  10. Seasonal Variation, Chemical Composition and Antioxidant activity of Brazilian Propolis Samples

    Microsoft Academic Search

    Erica Weinstein Teixeira; Dejair Message; Giuseppina Negri; Antonio Salatino; Paulo Cesar Stringheta

    2008-01-01

    Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin-Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC\\/MS. Propolis from Itapecerica and Paula Candido municipalities were found to have high

  11. Chemical Composition of Different Botanical Origin Honeys Produced by Sicilian Black Honeybees (Apis mellifera ssp. sicula).

    PubMed

    Mannina, Luisa; Sobolev, Anatoly P; Di Lorenzo, Arianna; Vista, Silvia; Tenore, Gian Carlo; Daglia, Maria

    2015-07-01

    In 2008 a Slow Food Presidium was launched in Sicily (Italy) for an early warning of the risk of extinction of the Sicilian native breed of black honeybee (Apis mellifera L. ssp sicula). Today, the honey produced by these honeybees is the only Sicilian honey produced entirely by the black honeybees. In view of few available data regarding the chemical composition of A. mellifera ssp. sicula honeys, in the present investigation the chemical compositions of sulla honey (Hedysarum coronarium L.) and dill honey (Anethum graveolens L.) were studied with a multimethodological approach, which consists of HPLC-PDA-ESI-MSn and NMR spectroscopy. Moreover, three unifloral honeys (lemon honey (obtained from Citrus limon (L.) Osbeck), orange honey (Citrus arantium L.), and medlar honey (Eriobotrya japonica (Thunb.) Lindl)), with known phenol and polyphenol compositions, were studied with NMR spectroscopy to deepen the knowledge about sugar and amino acid compositions. PMID:25730368

  12. Mechanics of composite materials

    SciTech Connect

    Dvorak, G.J. (Inst. Center for Composite Materials and Structures, Rensselaer Polytechnic Inst. (US)); Laws, N. (Dept. of Mechanical Engineering, Univ. of Pittsburgh, PA (US))

    1988-01-01

    This book contains the following papers: crack growth resistance of TiB{sub 2} particulate/SiC matrix composite; constitutive relations of flexible composites under elastic deformation; determination of two kinds of composite plasticity: inclusions plastic vs. matrix plastic; 3-D analysis of transient interlaminar thermal stress of laminated composites; effect of seawater on the fracture toughness of pultruded rods; evaluation of new failure criterion for fibrous composite materials; and bridged cracks in fiber-reinforced composites.

  13. A Potential Use of 3-D Scanning to Evaluate the Chemical Composition of Pork Meat.

    PubMed

    Adamczak, Lech; Chmiel, Marta; Florowski, Tomasz; Pietrzak, Dorota; Witkowski, Marcin; Barczak, Tomasz

    2015-07-01

    The aim of this study was to determine the possibility of 3-D scanning method in chemical composition evaluation of pork meat. The sampling material comprised neck muscles (1000 g each) obtained from 20 pork carcasses. The volumetric estimation process of the elements was conducted on the basis of point cloud collected using 3-D scanner. Knowing the weight of neck muscles, their density was calculated which was subsequently correlated with the content of basic chemical components of the pork meat (water, protein and fat content, determined by standard methods). The significant correlations (P ? 0.05) between meat density and water (r = 0.5213), protein (r = 0.5887), and fat (r = -0.6601) content were obtained. Based on the obtained results it seems likely to employ the 3-D scanning method to compute the meat chemical composition. PMID:25998468

  14. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1983-01-01

    Transverse properties of fiber constituents in composites, fatigue in composite materials, matrix dominated properties of high performance composites, numerical investigation of moisture effects, numerical investigation of the micromechanics of composite fracture, advanced analysis methods, compact lug design, and the RP-1 and RP-2 sailplanes projects are discussed.

  15. Chemical composition of Mars

    USGS Publications Warehouse

    Morgan, J.W.; Anders, E.

    1979-01-01

    The composition of Mars has been calculated from the cosmochemical model of Ganapathy and Anders (1974) which assumes that planets and chondrites underwent the same 4 fractionation processes in the solar nebula. Because elements of similar volatility stay together in these processes, only 4 index elements (U, Fe, K and Tl or Ar36) are needed to calculate the abundances of all 83 elements in the planet. The values chosen are U = 28 ppb, K = 62 ppm (based on K U = 2200 from orbital ??-spectrometry and on thermal history calculations by Tokso??z and Hsui (1978) Fe = 26.72% (from geophysical data), and Tl = 0.14 ppb (from the Ar36 and Ar40 abundances measured by Viking). The mantle of Mars is an iron-rich [Mg/(Mg + Fe) = 0.77] garnet wehrlite (?? = 3.52-3.54 g/cm3), similar to McGetchin and Smyth's (1978) estimate but containing more Ca and Al. It is nearly identical to the bulk Moon composition of Morgan et al. (1978b). The core makes up 0.19 of the planet and contains 3.5% S-much less than estimated by other models. Volatiles have nearly Moon-like abundances, being depleted relative to the Earth by factors of 0.36 (K-group, Tcond = 600-1300 K) or 0.029 (Tl group, Tcond < 600 K). The water abundance corresponds to a 9 m layer, but could be higher by as much as a factor of 11. Comparison of model compositions for 5 differentiated planets (Earth, Venus, Mars, Moon, and eucrite parent body) suggests that volatile depletion correlates mainly with size rather than with radial distance from the Sun. However, the relatively high volatile content of shergottites and some chondrites shows that the correlation is not simple; other factors must also be involved. ?? 1979.

  16. 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.

  17. Tough Composite Materials

    NASA Technical Reports Server (NTRS)

    Vosteen, L. F. (compiler); Johnson, N. J. (compiler); Teichman, L. A. (compiler)

    1984-01-01

    Papers and working group summaries are presented which address composite material behavior and performance improvement. Topic areas include composite fracture toughness and impact characterization, constituent properties and interrelationships, and matrix synthesis and characterization.

  18. Nano-composite materials

    DOEpatents

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  19. Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical vapor deposition

    E-print Network

    Dietz, Nikolaus

    Surface structure, composition, and polarity of indium nitride grown by high-pressure chemical of the surface was observed, N-polarity indium nitride is indicated. © 2006 American Institute of Physics. DOI: 10.1063/1.2187513 Research on the growth and characterization of indium nitride InN has increased

  20. Prediction of chemical contaminants and food compositions by near infrared spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Prediction of Food Adulteration by Infrared Spectroscopy H. Zhuang Quality and Safety Assessment Research Unit, ARS-USDA, 950 College Station Road, Athens, GA 30605 Food adulteration, including both chemical contamination and composition alternation, has been one of major quality and/or safety c...

  1. One-step synthesis and chemical characterization of Pt-C nanowire composites by plasma sputtering

    E-print Network

    Boyer, Edmond

    One-step synthesis and chemical characterization of Pt-C nanowire composites by plasma sputtering and strategic metals from the platinum group.[5] Here, a high surface-to-volume ratio leading to large fraction to obtain the highest catalytic surface area from a low metal weight, as for fuel cells [9] or sensors

  2. Plant response to drought stress simulated by ABA application: Changes in chemical composition of cuticular waxes

    Microsoft Academic Search

    Jana Macková; Martina Vašková; Petr Macek; Marie Hronková; Lukas Schreiber; Ji?í Šantr??ek

    2010-01-01

    Plant cuticles form the interface between epidermal plant cells and the atmosphere. The cuticle creates an effective barrier against water loss, bacterial and fungal infection and also protects plant tissue from UV radiation. It is composed of the cutin matrix and embedded soluble lipids also called waxes. Chemical composition of cuticular waxes and physiological properties of cuticles are affected by

  3. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1979-01-01

    A multifaceted program is described in which aeronautical, mechanical, and materials engineers interact to develop composite aircraft structures. Topics covered include: (1) the design of an advanced composite elevator and a proposed spar and rib assembly; (2) optimizing fiber orientation in the vicinity of heavily loaded joints; (3) failure mechanisms and delamination; (4) the construction of an ultralight sailplane; (5) computer-aided design; finite element analysis programs, preprocessor development, and array preprocessor for SPAR; (6) advanced analysis methods for composite structures; (7) ultrasonic nondestructive testing; (8) physical properties of epoxy resins and composites; (9) fatigue in composite materials, and (10) transverse thermal expansion of carbon/epoxy composites.

  4. Size-resolved chemical composition of aerosol emitted by Erebus volcano, Antarctica

    NASA Astrophysics Data System (ADS)

    Ilyinskaya, E.; Oppenheimer, C.; Mather, T. A.; Martin, R. S.; Kyle, P. R.

    2010-03-01

    Persistent, open-vent degassing of Erebus volcano, Antarctica, is a significant point source of gases and aerosol to the austral polar troposphere. We report here on the chemical composition and size distribution of the Erebus aerosol, focusing on the water-soluble fraction. The aerosol was sampled at the rim of the active crater using a cascade impactor, which collected and sized particles in 14 size bins from >10 to 0.01 ?m. The soluble fraction of the Erebus aerosol is distinct from other volcanic sources in several respects. It is dominated by chloride-bearing particles (over 30% of total mass) and has an unusually high Cl-/SO42- molar ratio of 3.5. Coarse particles contribute little to the total mass of the soluble fraction. Elevated concentrations of F-, Cl-, Br-, and SO42- are found in a narrow particle size fraction of 0.1-0.25 ?m. The detection of particulate Br- reinforces our understanding of the potential for quiescent volcanic emissions to deplete tropospheric ozone. The small aerosol size reflects the low atmospheric temperature and humidity, which inhibit particle growth. Halide-alkali metal salts (Na, K)(Cl, F) appear to be the most abundant species in the aerosol. The concentration of Pb is high compared to other volcanoes; its exsolution may be promoted by the high abundance of halogens in Erebus magma. Despite the previously reported high NOx content in the plume, we did not detect significant quantities of nitrate in the near-vent aerosol. Our findings emphasize the potential regional significance of emissions from Erebus for understanding the Antarctic atmospheric composition and glaciochemical records.

  5. Effect of Sericin on Mechanical Behavior of Composite Material Reinforced by Silk Woven Fabric

    NASA Astrophysics Data System (ADS)

    Kimura, Teruo; Ino, Haruhiro; Hanada, Koji; Katori, Sigetaka

    Recent, attention has been given to shift from glass fibers and carbon fibers to natural fibers for FRP composites for the goal of protecting the environment. This paper concerned with the application of silk fabric for composite materials. Polypropylene (PP) was used for the matrix material and the silk fabric composites were molded using a compression molding method. Especially, the effect of sericin on mechanical behaviors of composite materials was discussed. Good adhesion between silk and PP was obtained by removing the sericin existing around the fibroin. The tensile modulus of composite decreased with decreasing the sericin because of the flexibility of silk fibers without sericin. In particular, the higher Izod impact value was obtained for the composites containing the silk fibers without sericin.

  6. Composite electric contact materials

    NASA Astrophysics Data System (ADS)

    Senkara, J.; Kowalczyk, J.

    1985-12-01

    Two-phase composite materials, i.e., a high-melting component combined with a material exhibiting good electrical and thermal properties find a wide range of application for the manufacture of small- and medium-load relays and switches. Composite contacts can be used in air circuit-breakers (W-Ag, Ag-Ni), oil circuit-breakers (W-Cu, Mo-Cn), vacuum-type switches (W-CuSb, CuCr), and also switches operating in an atmosphere of SF sub 6 (W-Cu). Present-day trends aimed at increasing operating reliability and extending the service life of electrical equipment are finding their expression in efforts being made to modify the classical composites with a veiw to imparting new properties to them by suitably changing their composition and structure. These trends are also aimed at reducing the consumption of noble metals and of strategically important ones. Modern materials engineering and metallurgical technologies are being used, including isostatic sintering or explosive forming. Owing to the high activity of the constituents, all processes are conducted under high vacuum or in pure reducing atmospheres.

  7. Synthesis of alumina–silicon carbide composites by chemically activated self-propagating reactions

    Microsoft Academic Search

    Larisa S. Abovyan; Hayk H. Nersisyan; Suren L. Kharatyan; Roberto Orrù; Rita Saiu; Giacomo Cao; Davide Zedda

    2001-01-01

    The synthesis of alumina\\/silicon carbide composites by self-propagating reactions activated by Teflon is investigated. It is shown that small amounts of this material (i.e. 0.20–0.25 wt.%) guarantee the occurrence of self-propagation reactions leading to the formation of a composite. In particular, under argon atmosphere, it consists of well-formed crystals of alumina, fine grained silicon carbide and whiskers-shaped crystallites of SiC.

  8. COMPOSITE MATERIALS PRODUCED BY PARTICLE-BONDING WITH GLIADIN AS A GLUE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In our previous report, we introduced a new methodology for the production of biodegradable polymer composites that will potentially replace existing petroleum-based polymers. Unlike conventional techniques that produce polymer composites by mixing the component materials in the extruder at high te...

  9. Preparation of 3YSZ\\/Cu composite by in-situ chemical route

    Microsoft Academic Search

    Jian Ding; Naiqin Zhao; Chunsheng Shi; Xiwen Du; Chunnian He; Jiajun Li

    2007-01-01

    To improve electrical and mechanical properties of electrodes for contact welding, a 3 mol% yttria stabilized zirconia (3YSZ)\\u000a to reinforced copper matrix composite was developed by an in-situ chemical process. The microstructure and properties of the\\u000a in-situ composite were investigated. The results showed that in-situ nano-scale particles were uniformly dispersed in the\\u000a copper matrix by dispersed nano-particle and its cluster. Due

  10. 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.

  11. Chemical controls on the magnesium content of amorphous calcium carbonate

    NASA Astrophysics Data System (ADS)

    Blue, C. R.; Dove, P. M.

    2015-01-01

    Amorphous calcium carbonate (ACC) is a metastable phase that forms in diverse biogeochemical settings. This material can incorporate significant amounts of magnesium and other elements, but the conditions that regulate composition are not established. Using a mixed flow reactor method, we synthesize Mg-free ACC (control) and amorphous magnesium calcium carbonate (ACMC) under controlled chemical conditions to determine the relationship between composition and inorganic solution chemistry. Input solutions contained a constant initial Mg/Ca ratio of 5/1 with variable total carbonate concentration, pH, and supersaturation. Within the reactor, input solution chemistry evolves in proportion to the extent of precipitation whereby the initial Mg/Ca ratio increases to values as high as 14 at steady state conditions. By this approach, we produce reproducible quantities of ACMC with 24 to >70 mol% Mg to give compositions of Mg(0.24-0.72)Ca(0.76-0.28)CO3·1.42-1.63H2O. The primary control on ACMC composition is the steady state solution composition that develops in the reactor during precipitation. Analysis of the data shows the Mg content of ACMC is regulated by the interplay of three factors at steady state conditions: (1) Mg/Ca ratio; (2) total carbonate concentration; and (3) solution pH. Using the Henderson-Kracek model to estimate the partition coefficients for the Mg content of ACMC, we find KD is approximately constant at 0.047 ± 0.003 when steady state pH is less than 9.5, but values of KD triple as steady state pH increases from 9.5 to 10.3. Our KD values are lower than previous estimates that are based upon initial solution composition. In contrast, our estimates of KD are determined from the solution chemistry at steady state conditions and for pH conditions that are less extreme than previous experimental studies. We suggest the approach of using steady state composition to estimate KD gives a more accurate representation of relationships between ACMC composition and local conditions. The findings demonstrate local pH and total carbonate concentration can be regulated at the time of formation to produce Mg amorphous carbonates of a designated composition.

  12. Processing of plastic waste and scrap tires into chemical raw materials, especially by pyrolysis

    Microsoft Academic Search

    Walter Kaminsky

    1976-01-01

    An account of the occurrence of pyrolyzable material and the state of development of pyrolysis processes in the USA and Japan is followed by a description of laboratory and pilot-scale experiments designed to exploit the raw material content of pyrolyzable substances rather than the heating value. Plastic waste and scrap tires can be pyrolyzed to give up to 40 percent

  13. Investigation of the chemical composition-antibacterial activity relationship of essential oils by chemometric methods.

    PubMed

    Miladinovi?, Dragoljub L; Ili?, Budimir S; Mihajilov-Krstev, Tatjana M; Nikoli?, Nikola D; Miladinovi?, Ljiljana C; Cvetkovi?, Olga G

    2012-05-01

    The antibacterial effects of Thymus vulgaris (Lamiaceae), Lavandula angustifolia (Lamiaceae), and Calamintha nepeta (Lamiaceae) Savi subsp. nepeta var. subisodonda (Borb.) Hayek essential oils on five different bacteria were estimated. Laboratory control strain and clinical isolates from different pathogenic media were researched by broth microdilution method, with an emphasis on a chemical composition-antibacterial activity relationship. The main constituents of thyme oil were thymol (59.95%) and p-cymene (18.34%). Linalool acetate (38.23%) and ?-linalool (35.01%) were main compounds in lavender oil. C. nepeta essential oil was characterized by a high percentage of piperitone oxide (59.07%) and limonene (9.05%). Essential oils have been found to have antimicrobial activity against all tested microorganisms. Classification and comparison of essential oils on the basis of their chemical composition and antibacterial activity were made by utilization of appropriate chemometric methods. The chemical principal component analysis (PCA) and hierachical cluster analysis (HCA) separated essential oils into two groups and two sub-groups. Thyme essential oil forms separate chemical HCA group and exhibits highest antibacterial activity, similar to tetracycline. Essential oils of lavender and C. nepeta in the same chemical HCA group were classified in different groups, within antibacterial PCA and HCA analyses. Lavender oil exhibits higher antibacterial ability in comparison with C. nepeta essential oil, probably based on the concept of synergistic activity of essential oil components. PMID:22389175

  14. Chemically produced tungsten-praseodymium oxide composite sintered by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Ding, Xiao-Yu; Luo, Lai-Ma; Lu, Ze-Long; Luo, Guang-Nan; Zhu, Xiao-Yong; Cheng, Ji-Gui; Wu, Yu-Cheng

    2014-11-01

    Pr2O3 doped W composite were synthesized by a novel wet chemical method and spark plasma sintering. The grain size, relative density and the Vicker hardness HV0.2 of Pr2O3/W samples were 4 ?m, 98.3% and 377.2, respectively. The tensile strength values of Pr2O3/W were higher than those of pure W. As the temperature rises from 25 °C to 800 °C, the conductivity of pure W and W-1 wt% Pr2O3 composites decreased with the same trend, was above 150 W/m K.

  15. Smart multiphase composite materials that repair themselves by a release of liquids that become solids

    Microsoft Academic Search

    Carolyn M. Dry

    1994-01-01

    The subject of this research in fracture mechanics is the enhancement of flexural toughening beyond the original hardened material by the release of liquid `healing' chemicals such as adhesives from hollow fibers into cementitious matrices in response to loading. These chemicals solidify in the cracks to impart an increased toughness and ductility. The mechanisms appear to be adhesive rebonding of

  16. Corrosion protection of Al alloys and Al-based metal-matrix composites by chemical passivation

    SciTech Connect

    Mansfeld, F.; Lin, S.; Sim, S.; Shih, H.

    1989-08-01

    Chemical passivation by immersion of aluminium alloys and aluminium 6061/ silicon carbide and aluminium 6061/graphite metal-matrix composites in cerium chloride solution produces very corrosion-resistant surfaces. Aluminium 6061 and aluminium 7075-T6 that had been immersed in 1000 ppm cerium chloride for one week did not suffer from pitting corrosion during immersion in acerated 0.5 N NaCl for three weeks. For aluminium 7075-T7l3 some improvement of the corrosion resistance was also achieved, but to a much lesser extent. Chemical passivation in cerium chloride was also successful for aluminium/silicon carbide and Allgraphite.

  17. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R.; Wiberley, S. E.

    1986-01-01

    Overall emphasis is on basic long-term research in the following categories: constituent materials, composite materials, generic structural elements, processing science technology; and maintaining long-term structural integrity. Research in basic composition, characteristics, and processing science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to present and future problems. Detailed descriptions of the progress achieved in the various component parts of this comprehensive program are presented.

  18. Electrically conductive composite material

    DOEpatents

    Clough, Roger L. (Albuquerque, NM); Sylwester, Alan P. (Albuquerque, NM)

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  19. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1989-05-23

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  20. Electrically conductive composite material

    DOEpatents

    Clough, R.L.; Sylwester, A.P.

    1988-06-20

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistent pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like. 2 figs.

  1. Metallic layered composite materials produced by explosion welding: Structure, properties, and structure of the transition zone

    NASA Astrophysics Data System (ADS)

    Mal'tseva, L. A.; Tyushlyaeva, D. S.; Mal'tseva, T. V.; Pastukhov, M. V.; Lozhkin, N. N.; Inyakin, D. V.; Marshuk, L. A.

    2014-10-01

    The structure, morphology, and microhardness of the transition zone in multilayer metallic composite joints are studied, and the cohesion strength of the plates to be joined, the mechanical properties of the formed composite materials, and fracture surfaces are analyzed. The materials to be joined are plates (0.1-1 mm thick) made of D16 aluminum alloy, high-strength maraging ZI90-VI (03Kh12N9K4M2YuT) steel, BrB2 beryllium bronze, and OT4-1 titanium alloy. Composite materials made of different materials are shown to be produced by explosion welding. The dependence of the interface shape (smooth or wavelike) on the physicomechanical properties of the materials to be joined is found. The formation of a wavelike interface is shown to result in the formation of intense-mixing regions in transition zones. Possible mechanisms of layer adhesion are discussed.

  2. Metal-nanocluster composites made by ion implantation: A novel third-order nonlinear material

    SciTech Connect

    Haglund, R.F. Jr.; Yang, L.; Magruder, R.H. III; Becker, K.; Wittig, J.E. [Vanderbilt Univ., Nashville, TN (United States); White, C.W.; Zhur, R.A. [Oak Ridge National Lab., TN (United States); Yang, L.; Dorsinville, R.; Alfano, R.R. [City Univ. of New York, NY (United States)

    1993-03-01

    We describe our recent studies of metal-insulator nanocluster composites made by ion implantation in such substrates as glass and sapphire. The metal clusters have diameters ranging from 3 to 30 nm. The composites exhibit an electronic nonlinear optical response which is fast on the picosecond time scale. In addition to possibilities for technological application, these materials also offer a way of studying unusual properties of composite materials, such as the quantum confinement of conduction-band electrons and the transverse relaxation time T{sub 2} as a function of cluster size.

  3. Metal-nanocluster composites made by ion implantation: A novel third-order nonlinear material

    SciTech Connect

    Haglund, R.F. Jr.; Yang, L.; Magruder, R.H. III; Becker, K.; Wittig, J.E. (Vanderbilt Univ., Nashville, TN (United States)); White, C.W.; Zhur, R.A. (Oak Ridge National Lab., TN (United States)); Yang, L.; Dorsinville, R.; Alfano, R.R. (City Univ. of New York, NY (United States))

    1993-03-01

    We describe our recent studies of metal-insulator nanocluster composites made by ion implantation in such substrates as glass and sapphire. The metal clusters have diameters ranging from 3 to 30 nm. The composites exhibit an electronic nonlinear optical response which is fast on the picosecond time scale. In addition to possibilities for technological application, these materials also offer a way of studying unusual properties of composite materials, such as the quantum confinement of conduction-band electrons and the transverse relaxation time T[sub 2] as a function of cluster size.

  4. Energetic composites and method of providing chemical energy

    DOEpatents

    Danen, Wayne C. (Los Alamos, NM); Martin, Joe A. (Espanola, NM)

    1997-01-01

    A method for providing chemical energy and energetic compositions of matter consisting of thin layers of substances which will exothermically react with one another. The layers of reactive substances are separated by thin layers of a buffer material which prevents the reactions from taking place until the desired time. The reactions are triggered by an external agent, such as mechanical stress or an electric spark. The compositions are known as metastable interstitial composites (MICs). This class of compositions includes materials which have not previously been capable of use as energetic materials. The speed and products of the reactions can be varied to suit the application.

  5. In-situ DLC/TiC composite coating by plasma enhanced chemical vapor deposition

    SciTech Connect

    Wang, Hsiao Lei; Hon, Min Hsiung [National Cheng Kung Univ., Tainan (Taiwan, Province of China)

    1995-12-31

    In-situ diamond like carbon (DLC)/TiC composite film was coated on silicon wafer, steel and glass substrates with titanium chloride, methane, hydrogen and argon gas mixtures by R.F. plasma enhanced chemical vapor deposition. Raman spectra showed the coexistance of DLC and TiC in the films. The growth rate and DLC/TiC ratio of these films were investigated as a function of the inert gas flow rate.

  6. Corrosion protection of Al alloys and Al-based metal-matrix composites by chemical passivation

    Microsoft Academic Search

    F. Mansfeld; S. Lin; S. Sim; H. Shih

    1989-01-01

    Chemical passivation by immersion of aluminium alloys and aluminium 6061\\/ silicon carbide and aluminium 6061\\/graphite metal-matrix composites in cerium chloride solution produces very corrosion-resistant surfaces. Aluminium 6061 and aluminium 7075-T6 that had been immersed in 1000 ppm cerium chloride for one week did not suffer from pitting corrosion during immersion in acerated 0.5 N NaCl for three weeks. For aluminium

  7. Thermoelastic constitutive equations for chemically hardening materials

    NASA Technical Reports Server (NTRS)

    Shaffer, B. W.; Levitsky, M.

    1974-01-01

    Thermoelastic constitutive equations are derived for a material undergoing solidification or hardening as the result of a chemical reaction. The derivation is based upon a two component model whose composition is determined by the degree of hardening, and makes use of strain-energy considerations. Constitutive equations take the form of stress rate-strain rate relations, in which the coefficients are time-dependent functions of the composition. Specific results are developed for the case of a material of constant bulk modulus which undergoes a transition from an initial liquidlike state into an isotropic elastic solid. Potential applications are discussed.

  8. Chemical composition, digestibility, and voluntary feed intake of mango residues by sheep.

    PubMed

    Sanon, Hadja Oumou; Kanwe, Augustin B; Millogo, Alain; Ledin, Inger

    2013-02-01

    The chemical composition, digestibility, and voluntary feed intake by sheep of mango by-products were studied in an experiment with five dietary treatments consisting of mango peels and seed kernels, offered individually or together with urea block and a control. The mango residues were offered with rice straw and the control diet was straw only. Five groups of five male sheep of Djallonké type, 12-18 months old and weighing on average 18.6 kg were allocated randomly to the diets to assess the voluntary feed intake. Apparent digestibility of the same diets was measured using four sheep per diet. The mango residues were low in crude protein, 67 and 70 g/kg dry matter for the peels and the seed kernels, respectively. The content of neutral detergent fiber varied from 306 to 388 g/kg dry matter (DM) for the kernel and the peels, respectively. The kernel had relatively high level of fat (105 g/kg DM) and tannins (29 and 40 g/kg DM of hydrolysable and total tannins, respectively). The highest intake was observed with the diet containing both residues and urea block (741 g/day). The intake of kernels was lower in all diets when offered with the peels than when offered with rice straw alone. Apparent digestibility of the diets containing mango residues was 0.60-0.65. The peels and kernels had high digestibility coefficients (0.74 and 0.70, respectively). Based on the results above, it can be concluded that it would be interesting to test the residues in a growth experiment. PMID:23054805

  9. Production by various methods of composite materials based on a hard metal with cubic boron nitride

    Microsoft Academic Search

    V. D. Andreev; V. P. Bondarenko; A. M. Baranovskii; V. P. Pereyaslov; V. P. Kolomiets; I. V. Manzheleev; N. I. Chukhno

    1983-01-01

    During the production of the composite materials under consideration by orthodox sintering the cubic boron nitride and hard metal react with each other, with the formation of borides and appearance of porosity as a result of the evolution of gaseous reaction products, and the strength of the materials is therefore low. During hot pressing the reaction between the components of

  10. Carbon\\/silicon carbide composites prepared by chemical vapor infiltration combined with silicon melt infiltration

    Microsoft Academic Search

    Yongdong Xu; Laifei Cheng; Litong Zhang

    1999-01-01

    In order to reduce processing costs and improve the thermal stability of three-dimensional carbon fiber-reinforced silicon carbide composites, a chemical vapor infiltration combined with silicon melt infiltration method was developed for fabricating composites. According to the size of the pores in the preform, chemical vapor infiltration (CVI) and silicon melt infiltration (SMI) were mainly used to infiltrate small pores between

  11. Composite material and method of making

    DOEpatents

    Fryxell, Glen E.; Samuels, William D.; Simmons, Kevin L.

    2004-04-20

    The composite material and methods of making the present invention rely upon a fully dense monolayer of molecules attached to an oxygenated surface at one end, and an organic terminal group at the other end, which is in turn bonded to a polymer. Thus, the composite material is a second material chemically bonded to a polymer with fully dense monolayer there between.

  12. Composite Material Switches

    NASA Technical Reports Server (NTRS)

    Javadi, Hamid (Inventor)

    2001-01-01

    A device to protect electronic circuitry from high voltage transients is constructed from a relatively thin piece of conductive composite sandwiched between two conductors so that conduction is through the thickness of the composite piece. The device is based on the discovery that conduction through conductive composite materials in this configuration switches to a high resistance mode when exposed to voltages above a threshold voltage.

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1982-01-01

    Research in the basic composition, characteristics, and processng science of composite materials and their constituents is balanced against the mechanics, conceptual design, fabrication, and testing of generic structural elements typical of aerospace vehicles so as to encourage the discovery of unusual solutions to problems. Detailed descriptions of the progress achieved in the various component parts of his program are presented.

  14. Mechanics of Composite Materials

    Microsoft Academic Search

    Robert M. Jones

    1999-01-01

    The mechanical behavior of composites is traditionally evaluated on both microscopic and macroscopic scale to take into account inhomogeneity. Micromechanics attempts to quantify the interactions of fiber and matrix (reinforcement and resin) on a microscopic scale on par with the diameter of a single fiber. Macromechanics treats composites as homogeneous materials, with mechanical properties representative of the laminate as a

  15. Composite Aluminum-Copper Sheet Material by Friction Stir Welding and Cold Rolling

    NASA Astrophysics Data System (ADS)

    Kahl, S.; Osikowicz, W.

    2013-08-01

    An aluminum alloy and a pure copper material were butt-joined by friction stir welding and subsequently cold rolled. The cold-rolling operation proved to be very advantageous because small voids present after friction stir welding were closed, the interface area per material thickness was enlarged, a thin intermetallic layer was partitioned, and the joint was strengthened by strain hardening. Tensile test specimens fractured in the heat-affected zone in the aluminum material; tensile strengths of the joints exceeded the tensile strengths of the base materials and were as high as 335 MPa. During soft annealing of the composite material, a 6-8-?m-thick intermetallic layer was grown at the interface. Nevertheless, tensile fracture still occurred in the heat-affected zone of the aluminum material. Electrical resistivity of the joint was smaller than resistivity of the aluminum material. Production of such composite material would result in coiled sheet material that could be subjected to further treatments such as electroplating and forming operations in an efficient and economically viable manner. The new composite material is promising for emerging automotive and industrial electrical applications.

  16. The “zircon effect” as recorded by the chemical and Hf isotopic compositions of Lesser Antilles forearc sediments

    NASA Astrophysics Data System (ADS)

    Carpentier, Marion; Chauvel, Catherine; Maury, René C.; Mattielli, Nadine

    2009-09-01

    Oceanic sediments contain the products of erosion of continental crust, biologic activity and chemical precipitation. These processes create a large diversity of their chemical and isotopic compositions. Here we focus on the influence of the distance from a continental platform on the trace element and isotopic compositions of sediments deposited on the ocean floor and highlight the role of zircons in decoupling high-field strength elements and Hf isotopic compositions from other trace elements and Nd isotopic compositions. We report major and trace element concentrations as well as Sr and Hf isotopic data for 80 sediments from the Lesser Antilles forearc region. The trace-element characteristics and the Sr and Hf isotopic compositions are generally dominated by detrital material from the continental crust but are also variably influenced by chemical or biogenic carbonate and pure biogenic silica. Next to the South American continent, at DSDP Site 144 and on Barbados Island, sediments, coarse quartz arenites, exhibit marked Zr and Hf excesses that we attribute to the presence of zircon. In contrast, the sediments from DSDP Site 543, which were deposited farther away from the continental platform, consist of fine clay and they show strong deficiencies in Zr and Hf. The enrichment or depletion of Zr-Hf is coupled to large changes in Hf isotopic compositions (- 30 < ?Hf < + 4) that vary independently from the Nd isotopes. We interpret this feature as a clear expression of the "zircon effect" suggested by Patchett and coauthors in 1984. Zircon-rich sediments deposited next to the South American continent have very low ?Hf values inherited from old zircons. In contrast, in detrital clay-rich sediments deposited a few hundred kilometers farther north, the mineral fraction is devoid of zircon and they have drastically higher ?Hf values inherited from finer, clay-rich continental material. In the two DSDP sites, average Hf isotopes are very unradiogenic relative to other oceanic sediments worldwide ( ?Hf = - 14.4 and - 7.4) and they define the low Hf end member of the sedimentary field in Hf-Nd space. Their compositions correspond to end members that, when mixed with mantle, are able to reproduce the pattern of volcanic rocks from the Lesser Antilles. More generally, we find a relationship between Nb/Zr ratios and the vertical deviation of Hf isotope ratios from the Nd-Hf terrestrial array and we suggest that this relationship can be used as a tool to distinguish sediment input from fractionation during melting during the formation of arc lavas.

  17. Standardized evaluation of chemical compositions of LiTaO3 single crystals for SAW devices using the LFB ultrasonic material characterization system.

    PubMed

    Kushibiki, Jun-ichi; Ohashi, Yuji; Ujiie, Takaaki

    2002-04-01

    The line-focus-beam ultrasonic material characterization (LFB-UMC) system is applied to compare and evaluate tolerances provided independently for the Curie temperature T(C) and lattice constant a to evaluate commercial LiTaO3 single crystals by measuring the Rayleigh-type leaky surface acoustic wave (LSAW) velocities V(LSAW). The relationships between V(LSAW), and T(C) and a measured by individual manufacturers were obtained experimentally using 42 degrees Y X-LiTaO3 wafers as specimens from three crystal manufacturers. In addition, the relationship between V(LSAW) and SH-type SAW velocities V(SAW) that are actually used for the SAW device wafers was obtained through calculations, using the chemical composition dependences of the acoustical physical constants for LiTaO3 crystals reported previously. The result of a comparison between the T(C) tolerance of +/-3 degrees C and the a tolerance of +/-0.00002 nm through the common scale of V(LSAW) or V(SAW) demonstrated that the a tolerance is 1.6 times larger than the T(C) tolerance. Furthermore, we performed a standardized comparison of statistical data of T(C) and a for LiTaO3 crystals grown by two manufacturers during 1999 and 2000, using V(LSAW). The results clarified the differences of the average chemical compositions and of the chemical composition distributions among the crystal ingots between the two manufacturers. A guideline for the standardized evaluation procedure has been established for the SAW-device wafer specifications by the LFB-UMC system. PMID:11989701

  18. Thermomechanical properties of egg albumen–cassava starch composite films containing sunflower-oil droplets as influenced by moisture content

    Microsoft Academic Search

    S. Wongsasulak; T. Yoovidhya; S. Bhumiratana; P. Hongsprabhas; D. J. McClements; J. Weiss

    2006-01-01

    The effect of moisture content on the thermo-mechanical and structural properties of egg albumen–cassava starch composite films containing sunflower oil droplets was studied using dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Composite films were prepared by cold gelation, dried in a moisture controlled incubator (83.5%RH) at 25°C for 8days and aged at different relative

  19. Chemical vapor deposition prepared bi-morphological carbon-coated Fe3O4 composites as anode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Wang, Junhua; Gao, Mingxia; Wang, Dingsheng; Li, Xiang; Dou, Yibo; Liu, Yongfeng; Pan, Hongge

    2015-05-01

    Carbon coated Fe3O4 composite (Fe3O4@C) with bi-morphological architecture has been prepared via a chemical vapor deposition at 450 °C from Fe2O3 nanoparticles by using acetylene as the deposition vapor and carbon source. The Fe2O3 are fully reduced to Fe3O4 in a 10 min of deposition, showing submicron-sized octahedral Fe3O4 particles coated partially with a thin carbon layer mainly, and a few nano-sized Fe3O4 particles coated with carbon also. The deposition period of 20 min results in a further growth of the octahedral Fe3O4 particles and a reduction of the number of the nano-sized ones, correlating to a thick and fully coated carbon layer. Impurities of iron carbides generate in the composite with further prolonging the deposition to 30 min. The Fe3O4@C composite from 20 min of deposition shows superior electrochemical property to others. An initial reversible capacity of 570 mAh g-1 is obtained and the capacity fading is less than 5% after 60 cycles. The fabrication method is facile and time-saving. Such submicron size-predominated Fe3O4@C composite is hopefully not only favorable in alleviating the agglomeration of the iron oxide during cycling, but also helpful in getting high packing density of the anode material.

  20. Aqueous chemical wash compositions

    SciTech Connect

    Bannister, C.E.

    1987-07-21

    This patent describes an aqueous, substantially unfoamed chemical wash composition having properties making it suitable for use as a pre-flush in well cementing operations and/or for removal of drilling mud from a borehole at a temperature of from about 150/sup 0/F to about 270/sup 0/F, the wash a. being predominantly composed of water, b. containing an active surfactant component comprising a combination of (1) from about 0.1 to about 1.5 weight percent (total weight basis) of a water soluble anionic surfactant; (2) from about 0.1 to about 1.5 weight percent (total weight basis) of a nonionic surfactant; and (3) from about 0.05 to about 0.54 weight percent (total weight basis) of at least one water soluble amphoteric surfactant, and c. having dispersed therein a heterogeneous mixture of distinct particles comprising both a first particulate oil soluble resin which is friable and a second particulate oil soluble resin which is pliable and where the size of the friable resin particles ranges from about 0.5 to about 300 microns and the size of the pliable resin particles ranges from about 0.05 to about 30 microns. The amount of the friable-pliable resin mixture is sufficient to impart effective fluid loss control to the chemical wash composition.

  1. Growth of crystals of several boron-carbon compositions by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Kevill, D. N.; Rissmann, T. J.; Brewe, D.; Wood, C.

    1986-01-01

    Boron-carbon compounds have been deposited by the flow of carbon tetrachloride and boron trichloride, in the presence of a large excess of hydrogen, over a graphite surface maintained at 1000-1300 C. Deposits were formed on either an RF-heated disc or a tube or insert heated by a resistance furnace. Crystalline materials ranging in composition from B2C to B17C have been obtained.

  2. Resin composite restorative materials.

    PubMed

    Ilie, N; Hickel, R

    2011-06-01

    This paper surveys the most important developments in resin-based dental composites and focuses on the deficits (e.g. polymerization shrinkage) and strengths of the materials and their clinical implications. Moreover, differences between composite categories, such as hybrid, nanohybrid, microfilled, packable, ormocer-based, silorane-based, polyacid-modified composites (compomers) and flowable composites are highlighted, especially in view of their mechanical behaviour. In addition to the classical dimethacrylate-based composites, special attention is given to alternative monomers, such as siloranes, ormocers or high-molecular-weight dimethacrylate monomers (e.g. dimer acid-based dimethacrylates and tricyclodecane (TCD)-urethane), analysing their advantages, behaviour and abilities. Finally, the paper attempts to establish the needs and wishes of clinicians for further development of resin-based composites. PMID:21564116

  3. Composition and cell wall content of diets selected by Roe deer, Red deer, Highland cattle and Konik ponies

    E-print Network

    Paris-Sud XI, Université de

    Composition and cell wall content of diets selected by Roe deer, Red deer, Highland cattle deer) will prefer to comsume less fibrous plant species than bulk and roughage feeders or grazers (Highland cattle) while intermediate feeders (Red deer) should take an intermediate position. As a large

  4. DIRECT DETERMINATION OF THE LIPID CONTENT IN STARCH-LIPID COMPOSITES BY TIME-DOMAIN NMR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch-lipid composites, prepared by excess steam jet-cooking aqueous mixtures of starch and lipid, are used in various applications for which their performance can depend upon accurate quantitation of lipid contained within these composites. A rapid and non-destructive method based on time-domain ...

  5. Composition Control of Barium Strontium Titanate Thin Films Prepared by Chemical Vapor Deposition

    Microsoft Academic Search

    Masahiro Kiyotoshi; Kazuhiro Eguchi; Keitaro Imai; Tsunetoshi Arikado

    1998-01-01

    Composition control of barium strontium titanate thin films prepared by chemical vapor deposition using Ba(THD)2, Sr(THD)2, and Ti(THD)2(i-OC3H7)2 (THD: 2,2,6,6-tetramethyl-3,5-heptanedionate) has been studied by investigating the effects of deposition temperature and the supply rates of metal sources. Although there were complicated correlations among the deposition rates of Ba, Sr, and Ti under kinetically limited conditions, the deposition rate ratio of

  6. Comparison of self repair in various composite matrix materials

    NASA Astrophysics Data System (ADS)

    Dry, Carolyn

    2014-04-01

    In a comparison of self repair in graphite composites (for airplane applications) versus epoxy and vinyl ester composites (for building structures or walls) 1 the type of damage that the fiber/matrix is prone to experience is a prime factor in determining which materials self repair well and 2 the flow of energy during damage determines what kinds of damage that can be self repaired well. 1) In brittle composites, repair was successful throughout the composite due to matrix cracking which allowed for optimum chemical flow, whereas in toughened composites that did not crack, the repair chemical flows into a few layers of the composite. 2) If the damage energy is stopped by the composite and goes laterally, it causes delamination which will be repaired; however if the damage energy goes through the composite as with a puncture, then there will be limited delamination, less chemical release and less self repair.

  7. Engineering of fluorescent emission of silk fibroin composite materials by material assembly.

    PubMed

    Lin, Naibo; Meng, Zhaohui; Toh, Guoyang William; Zhen, Yang; Diao, Yingying; Xu, Hongyao; Liu, Xiang Yang

    2015-03-01

    This novel materials assembly technology endows the designated materials with additional/enhanced performance by fixing "functional components" into the materials. Such functional components are molecularly recognized and accommodated by the designated materials. In this regard, two-photon fluorescence (TPF) organic molecules and CdTe quantum dots (QDs) are adopted as functional components to functionalize silk fibers and films. TPF organic molecules, such as, 2,7-bis[2-(4-nitrophenyl) ethenyl]-9,9-dibutylfluorene (NM), exhibit TPF emission quenching because of the molecular stacking that leads to aggregation in the solid form. The specific recognition between -NO2 in the annealed fluorescent molecules and the -NH groups in the silk fibroin molecules decouples the aggregated molecules. This gives rise to a significant increase in the TPF quantum yields of the silk fibers. Similarly, as another type of functional components, CdTe quantum dots (QDs) with different sizes were also adopted in the silk functionalization method. Compared to QDs in solution the fluorescence properties of functionalized silk materials display a long stability at room temperature. As the functional materials are well dispersed at high quantum yields in the biocompatible silk a TPF microscope can be used to pursue 3D high-resolution imaging in real time of the TPF-silk scaffold. PMID:25270616

  8. Predicción de la composición química del grano de sorgo mediante espectroscopía de reflectancia en el infrarrojo cercano (NIRS) Predicting the chemical composition of sorghum grain by near infrared reflectance spectroscopy (NIRS)

    Microsoft Academic Search

    Ericka Ramírez Rodríguez; Ana María Anaya Escalera; Gerardo Mariscal Landína

    In the calibration of a near infrared spectroscopy (NIRS) device to predict the chemical composition of sorghum grain, 216 sorghum grain samples were used throughout three years (1996, 1997 y 1998). Density, moisture, crude protein, neutral detergent fiber (NDF), and tannin contents were measured by determining sample NIRS spectrum using a 19-discrete-filter NIRS machine. Chemical results were subjected to a

  9. Differences between chemical element contents in hyperplastic and nonhyperplastic prostate glands investigated by neutron activation analysis.

    PubMed

    Zaichick, Vladimir; Zaichick, Sofia; Davydov, German

    2015-03-01

    In order to clarify the differences between Ag, Br, Ca, Co, Cr, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se, and Zn contents in hyperplastic (patients with benign prostate hyperplasia (BPH), n = 32) and nonhyperplastic (control group of healthy male inhabitants, n = 32) prostates, an instrumental neutron activation analysis was performed. Mean values (M ± S??) for mass fraction (mg/kg, dry mass basis) of chemical elements in glands of patients with BPH were the following: Ag, 0.0346 ± 0.0060; Br, 30.4 ± 3.6; Ca, 2030 ± 165; Co, 0.0716 ± 0.0097; Cr, 1.073 ± 0.119; Fe, 130.0 ± 7.9; Hg, 0.232 ± 0.030; K, 14,470 ± 740; Mg, 1200 ± 80; Mn, 1.19 ± 0.09; Na, 11,610 ± 870; Rb, 14.7 ± 0.8; Sb, 0.163 ± 0.025; Sc, 0.0257 ± 0.0040; Se, 1.243 ± 0.079; and Zn, 1235 ± 92. It was observed that in BPH tissue, the mass fraction of Co (p < 0.015), Cr (p < 0.0002), Hg (p < 0.000007), K (p < 0.001), Rb (p < 0.048), Sb (p < 0.0001), and Se (p < 0.000001) were significantly higher than in controls. In the sixth to eighth decades, the mass fractions of almost all chemical elements in hyperplastic prostates did not depend from age. Our finding of correlation between pairs of prostatic chemical element mass fractions indicates that there is a great disturbance of prostatic chemical element relationships with a benign hyperplastic transformation. The results apparently confirm the disturbed homeostasis of Zn and Se and some other chemical elements in the etiology of BPH. PMID:25519178

  10. Variation in corn stover composition and energy content with crop maturity

    Microsoft Academic Search

    L. O. Pordesimo; B. R. Hames; S. Sokhansanj; W. C. Edens

    2005-01-01

    How to harvest and process corn stover to maximize its quality as a fuel or industrial feedstock and minimize material losses are compelling issues in the industrial utilization of corn stover. The objectives of this investigation were to evaluate the variation in the chemical composition and energy content of aboveground components of the corn plant over time and to evaluate

  11. Micromechanics simulations of the viscoelastic properties of highly filled composites by the material point method (MPM)

    NASA Astrophysics Data System (ADS)

    Xue, Liping; Borodin, Oleg; Smith, Grant D.; Nairn, John

    2006-06-01

    Viscoelastic properties of the highly filled plastic-bonded explosive PBX-9501 were studied by two-dimensional dynamic material point method (MPM) simulations utilizing plasticized polymer binder and crystalline HMX constituent properties taken from experiment. The upper bound for the composite properties was estimated from iso-displacement boundary conditions, whereas the lower bound was estimated from iso-stress boundary conditions. A homogenized or 'dirty' binder approach was utilized to handle the multiple length scales involved in MPM simulations of highly filled composites with a broad distribution of filler particle sizes. Multiple time scale challenges were addressed by conducting a series of simulations in which the speed of sound of the composite was systematically varied by adjusting material point masses. This approach was used to predict the homogenized time dependent shear modulus of PBX-9501 from nanoseconds to milliseconds yielding good agreement with experimental data.

  12. Characterization of forages by differential scanning calorimetry and prediction of their chemical composition and nutritive value

    Microsoft Academic Search

    J Walshaw; G. W Mathison; T. F Fenton; G Sedgwick; H Hsu; G Recinos-Diaz; A Suleiman

    1998-01-01

    Differential scanning calorimetry (DSC) measurements of grass and legume hay samples were made to determine the potential of using this technique to estimate forage chemical composition and cattle intake and digestibility parameters. Ninety-three hay samples were examined, with 56 samples being used for development of calibration equations relating 17 forage chemical parameters and animal measurements to heat fluxes in response

  13. Nanostructured polyaniline rice husk composite as adsorption materials synthesized by different methods

    NASA Astrophysics Data System (ADS)

    Tot Pham, Thi; Thanh Thuy Mai, Thi; Quy Bui, Minh; Mai, Thi Xuan; Yen Tran, Hai; Binh Phan, Thi

    2014-03-01

    Composites based on polyaniline (PANi) and rice husk (RH) were prepared by two methods: the first one was chemical method by combining RH contained in acid medium and aniline using ammonium persulfate as an oxidation agent and the second one was that of soaking RH into PANi solution. The presence of PANi combined with RH to form nanocomposite was clearly demonstrated by infrared (IR) spectra as well as by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. Lead(II) and cadmium(II) ion concentrations in solution before and after adsorption process on those composites were analysed by atomic adsorption spectroscopy. Of the above preparation methods, the soaking one provided a composite onto which the maximum adsorption capacity was higher for lead(II) ion (200 mg g?1), but lower for cadmium(II) ion (106.383 mg g?1) in comparison with the chemical one. However, their adsorption process occurring on both composites also fitted well into the Langmuir isotherm model.

  14. Production of copper-based rare earth composite metal materials by coprecipitation and applications for gaseous ammonia removal.

    PubMed

    Hung, Chang-Mao

    2011-04-01

    This study addresses the oxidation of ammonia (NH3) at temperatures between 423 and 673 K by selective catalytic oxidation (SCO) over a copper-based, rare earth composite metal material that was prepared by coprecipitating copper nitrate, lanthanum nitrate, and cerium nitrate at various molar ratios. The catalysts were characterized using Brunner, Emmett, and Teller spectroscopy, Fourier-transform infrared spectroscopy, Xray diffraction, ultraviolet-visible spectroscopy, cyclic voltammetric spectroscopy, and scanning electron microscopy. At a temperature of 673 K and an oxygen content of 4%, approximately 99.5% of the NH3 was reduced by catalytic oxidation over the 6:1:3 copper-lanthanum-cerium (molar ratio) catalyst. Nitrogen (N2) was the main product of this NH3-SCO process. Results from the activity and selectivity tests revealed that the optimal catalyst for catalytic performance had the highest possible cerium content and specific surface area (43 m2/g). PMID:21516940

  15. Composite materials for thermal energy storage: enhancing performance through microstructures.

    PubMed

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-05-01

    Chemical incompatibility and low thermal conductivity issues of molten-salt-based thermal energy storage materials can be addressed by using microstructured composites. Using a eutectic mixture of lithium and sodium carbonates as molten salt, magnesium oxide as supporting material, and graphite as thermal conductivity enhancer, the microstructural development, chemical compatibility, thermal stability, thermal conductivity, and thermal energy storage performance of composite materials are investigated. The ceramic supporting material is essential for preventing salt leakage and hence provides a solution to the chemical incompatibility issue. The use of graphite gives a significant enhancement on the thermal conductivity of the composite. Analyses suggest that the experimentally observed microstructural development of the composite is associated with the wettability of the salt on the ceramic substrate and that on the thermal conduction enhancer. PMID:24591286

  16. Aerogel/polymer composite materials

    NASA Technical Reports Server (NTRS)

    Williams, Martha K. (Inventor); Smith, Trent M. (Inventor); Fesmire, James E. (Inventor); Roberson, Luke B. (Inventor); Clayton, LaNetra M. (Inventor)

    2010-01-01

    The invention provides new composite materials containing aerogels blended with thermoplastic polymer materials at a weight ratio of aerogel to thermoplastic polymer of less than 20:100. The composite materials have improved thermal insulation ability. The composite materials also have better flexibility and less brittleness at low temperatures than the parent thermoplastic polymer materials.

  17. Specialized Content Material.

    ERIC Educational Resources Information Center

    Labbe, Raul; Varas, Amanda

    A computer-based set of instructional materials, designed to teach English second-language reading skills to university-level engineering students, is described and its development is outlined. The programmed units are designed to be used individually on the computer. The stages of software development included: selection of sentence units from…

  18. Chemical composition of acid–base fractions separated from biooil derived by fast pyrolysis of chicken manure

    Microsoft Academic Search

    Dharani D. Das; Morris I. Schnitzer; Carlos M. Monreal; Paul Mayer

    2009-01-01

    Our earlier investigations on the chemical composition of biooils derived by the fast pyrolysis of chicken manure revealed the presence of more than 500 compounds. In order to simplify this heterogeneous and complex chemical system, we produced four biooil fractions namely strongly acidic fraction A, weakly acidic fraction B, basic fraction C and neutral fraction D on the basis of

  19. Compositional, structural, and optical study of nanocrystalline ZnS thin films prepared by a new chemical bath deposition route

    Microsoft Academic Search

    Reza Sahraei; Ghaffar Motedayen Aval; Alireza Goudarzi

    2008-01-01

    Zinc sulphide nanocrystalline thin films are prepared by a new chemical bath deposition route on glass and quartz substrates using a weak acidic bath, in which nitrilotriacetic acid acts as a complexing agent and thioacetamide acts as a source of sulphide ions. The thickness of films varied from a few nm to 500nm. The chemical composition of films was determined

  20. An analysis of delamination in composite material notched tensile beams

    E-print Network

    Tangirala, Prema Kumar

    1991-01-01

    AN ANALYSIS OF DELAMINATION IN COMPOSITE MATERIAL NOTCHED TENSILE BEAMS A Thesis by PREMA KUMAR TANGIRALA 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 1991 Major Subject: Mechanical Engineering AN ANALYSIS OF DELAMINATION IN COMPOSITE MATERIAL NOTCHED TENSILE BEAMS A Thesis by PREMA KUMAR TANGIRALA Approved as to style and content by: H A. Hogan (Chair of Committee...

  1. UPDATED ESTIMATES OF THE SELENOMETHIONINE CONTENTS OF NIST WHEAT REFERENCE MATERIALS BY GC-IDMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Updated estimates of the selenomethionine contents of four NIST wheat reference materials have been obtained using a revised gas chromatography-stable isotope dilution mass spectrometry method. The revised method makes use of digestion with methanesulfonic acid, providing a more complete accounting ...

  2. Effect of the anode material on the composition and dimensional characteristics of the nano-sized copper-bearing powders produced by the electrochemical method

    Microsoft Academic Search

    M. V. Tesakova; V. I. Parfenyuk

    2010-01-01

    The effect of the anode material on the dimensional characteristics and chemical composition of the ultradispersed copper-bearing\\u000a powders produced by the electrochemical method from aqueous-organic solutions of copper sulphate has been investigated. A\\u000a complex physical and chemical study of the produced powders has been carried out. The sizes of the particles of the produced\\u000a powder have been determined according to

  3. Changes in chemical composition of bone matrix in ovariectomized (OVX) rats detected by Raman spectroscopy and multivariate analysis

    NASA Astrophysics Data System (ADS)

    Oshima, Yusuke; Iimura, Tadahiro; Saitou, Takashi; Imamura, Takeshi

    2015-02-01

    Osteoporosis is a major bone disease that connotes the risk of fragility fractures resulting from alterations to bone quantity and/or quality to mechanical competence. Bone strength arises from both bone quantity and quality. Assessment of bone quality and bone quantity is important for prediction of fracture risk. In spite of the two factors contribute to maintain the bone strength, only one factor, bone mineral density is used to determine the bone strength in the current diagnosis of osteoporosis. On the other hand, there is no practical method to measure chemical composition of bone tissue including hydroxyapatite and collagen non-invasively. Raman spectroscopy is a powerful technique to analyze chemical composition and material properties of bone matrix non-invasively. Here we demonstrated Raman spectroscopic analysis of the bone matrix in osteoporosis model rat. Ovariectomized (OVX) rat was made and the decalcified sections of tibias were analyzed by a Raman microscope. In the results, Raman bands of typical collagen appeared in the obtained spectra. Although the typical mineral bands at 960 cm-1 (Phosphate) was absent due to decalcified processing, we found that Raman peak intensities of amide I and C-C stretching bands were significantly different between OVX and sham-operated specimens. These differences on the Raman spectra were statistically compared by multivariate analyses, principal component analysis (PCA) and liner discrimination analysis (LDA). Our analyses suggest that amide I and C-C stretching bands can be related to stability of bone matrix which reflects bone quality.

  4. Waveform-based selection of acoustic emission events generated by damage in composite materials

    NASA Astrophysics Data System (ADS)

    Maillet, Emmanuel; Morscher, Gregory N.

    2015-02-01

    Acoustic emission (AE) has been shown to be a promising health monitoring technique for composite materials as it allows real-time location and identification of damage. When attempting to relate the recorded acoustic emission to a material's mechanical behavior, the relevance of results relies on an accurate selection of AE originating from material damage. Indeed, during mechanical tests most of the recorded AE is generated outside of the volume of interest and without proper filtering these AE signals can significantly affect the analysis. To date, there exists no common procedure for the selection of AE signals and therefore results can hardly be compared or transposed to different composite systems. In the present paper, a new waveform-based procedure is proposed for the selection of AE events generated by damage. The procedure includes accurate localization and selection assessment based on signal energy.

  5. Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications.

    PubMed

    Chen, Jun; Hu, Lei; Deng, Jinxia; Xing, Xianran

    2015-05-26

    Negative thermal expansion (NTE) is an intriguing physical property of solids, which is a consequence of a complex interplay among the lattice, phonons, and electrons. Interestingly, a large number of NTE materials have been found in various types of functional materials. In the last two decades good progress has been achieved to discover new phenomena and mechanisms of NTE. In the present review article, NTE is reviewed in functional materials of ferroelectrics, magnetics, multiferroics, superconductors, temperature-induced electron configuration change and so on. Zero thermal expansion (ZTE) of functional materials is emphasized due to the importance for practical applications. The NTE functional materials present a general physical picture to reveal a strong coupling role between physical properties and NTE. There is a general nature of NTE for both ferroelectrics and magnetics, in which NTE is determined by either ferroelectric order or magnetic one. In NTE functional materials, a multi-way to control thermal expansion can be established through the coupling roles of ferroelectricity-NTE, magnetism-NTE, change of electron configuration-NTE, open-framework-NTE, and so on. Chemical modification has been proved to be an effective method to control thermal expansion. Finally, challenges and questions are discussed for the development of NTE materials. There remains a challenge to discover a "perfect" NTE material for each specific application for chemists. The future studies on NTE functional materials will definitely promote the development of NTE materials. PMID:25864730

  6. Matrix Composition Regulates Three-Dimensional Network Formation by Endothelial Cells and Mesenchymal Stem Cells in Collagen/Fibrin Materials

    PubMed Central

    Rao, Rameshwar R.; Peterson, Alexis W.; Ceccarelli, Jacob; Putnam, Andrew J.; Stegemann, Jan P.

    2013-01-01

    Co-cultures of endothelial cells (EC) and mesenchymal stem cells (MSC) in three-dimensional (3D) protein hydrogels can be used to recapitulate aspects of vasculogenesis in vitro. MSC provide paracrine signals that stimulate EC to form vessel-like structures, which mature as the MSC transition to the role of mural cells. In this study, vessel-like network formation was studied using 3D collagen/fibrin (COL/FIB) matrices seeded with embedded EC and MSC and cultured for 7 days. The EC:MSC ratio was varied from 5:1, 3:2, 1:1, 2:3 and 1:5. The matrix composition was varied at COL/FIB compositions of 100/0 (pure COL), 60/40, 50/50, 40/60 and 0/100 (pure FIB). Vasculogenesis was markedly decreased in the highest EC:MSC ratio, relative to the other cell ratios. Network formation increased with increasing fibrin content in composite materials, although the 40/60 COL/FIB and pure fibrin materials exhibited the same degree of vasculogenesis. EC and MSC were co-localized in vessel-like structures after 7 days and total cell number increased by approximately 70%. Mechanical property measurements showed an inverse correlation between matrix stiffness and network formation. The effect of matrix stiffness was further investigated using gels made with varying total protein content and by crosslinking the matrix using the dialdehyde glyoxal. This systematic series of studies demonstrates that matrix composition regulates vasculogenesis in 3D protein hydrogels, and further suggests that this effect may be caused by matrix mechanical properties. These findings have relevance to the study of neovessel formation and the development of strategies to promote vascularization in transplanted tissues. PMID:22382584

  7. Characterization and chemical composition of fatty acids content of watermelon and muskmelon cultivars in Saudi Arabia using gas chromatography/mass spectroscopy

    PubMed Central

    Albishri, Hassan M.; Almaghrabi, Omar A.; Moussa, Tarek A. A.

    2013-01-01

    Background: The growth in the production of biodiesel, which is principally fatty acid methyl esters (FAME), has been phenomenal in the last ten years because of the general desire to cut down on the release of greenhouse gases into the atmosphere, and also as a result of the increasing cost of fossil fuels. Objective: Establish whether there is any relationship between two different species (watermelon and muskmelon) within the same family (Cucurbitaceae) on fatty acid compositions and enumerate the different fatty acids in the two species. Materials and Methods: Extraction of fatty acids from the two species and preparation the extract to gas chromatography/mass spectroscopy analysis to determine the fatty acids compositions qualitatively and quantitatively. Results: The analyzed plants (watermelon and muskmelon) contain five saturated fatty acids; tetrdecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid and octadecanoic acid with different concentrations, while muskmelon contains an extra saturated fatty acid named eicosanoic acid. The watermelon plant contains five unsaturated fatty acids while muskmelon contains three only, the two plants share in two unsaturated fatty acids named 9-hexadecenoic acid and 9-octadecenoic acid, the muskmelon plant contains higher amounts of these two acids (2.04% and 10.12%, respectively) over watermelon plant (0.88% and 0.25%, respectively). Conclusion: The chemical analysis of watermelon and muskmelon revealed that they are similar in saturated fatty acids but differ in unsaturated fatty acids which may be a criterion of differentiation between the two plants. PMID:23661995

  8. Ski Technology And Composite Materials

    NSDL National Science Digital Library

    2010-01-01

    The following resource is from Lessonopoly, which has created student activities and lesson plans to support the video series, Science of the Olympic Winter Games, created by NBC Learn and the National Science Foundation. Featuring exclusive footage from NBC Sports and contributions from Olympic athletes and NSF scientists, the series will help teach your students valuable scientific concepts. Students will learn the basic engineering issues related to ski design. They will learn about composite materials and polymer materials. Also, students will create and test a composite material.

  9. The chemical composition of Martian soil and rocks returned by the mobile alpha proton X-ray spectrometer: preliminary results from the X-ray mode.

    PubMed

    Rieder, R; Economou, T; Wänke, H; Turkevich, A; Crisp, J; Brückner, J; Dreibus, G; McSween, H Y

    1997-12-01

    The alpha proton x-ray spectrometer (APXS) on board the rover of the Mars Pathfinder mission measured the chemical composition of six soils and five rocks at the Ares Vallis landing site. The soil analyses show similarity to those determined by the Viking missions. The analyzed rocks were partially covered by dust but otherwise compositionally similar to each other. They are unexpectedly high in silica and potassium, but low in magnesium compared to martian soils and martian meteorites. The analyzed rocks are similar in composition to terrestrial andesites and close to the mean composition of Earth's crust. Addition of a mafic component and reaction products of volcanic gases to the local rock material is necessary to explain the soil composition. PMID:9388173

  10. Effect of Yarn Sizes on the Tensile Damage Evolution of a C/SiC Composite Fabricated by Chemical Vapor Infiltration

    NASA Astrophysics Data System (ADS)

    Wang, Yiqiang; Zhang, Litong; Cheng, Laifei

    2011-04-01

    The damage evolutions of C/SiC composites fabricated by chemical vapor infiltration with two different sizes of yarns were compared by cyclic tensile load/unload tests accompanied with the acoustic emission (AE) monitoring. The results show that an inflexion was observed in both the evolution of hysteresis characteristics and the corresponding AE curve for composite with fine yarns, which is, however, absent for composite with coarse yarns, suggesting that the former is much closer to the tough material than the latter one. Felicity effect was observed for both composites, which is more pronounced for the composite with coarse yarns due to the large yarn sizes leading to more matrix debris inside the yarns.

  11. Preparation and characterization of 5-sulphosalicylic acid doped tetraethoxysilane composite ion-exchange material by sol-gel method.

    PubMed

    Rehman, Suhail-ul; Islam, Nasarul; Ahad, Sozia; Fatima, Syed Zeeshan; Pandith, Altaf Hussain

    2013-09-15

    In this manuscript, we report the preparation and characterization of sulphosalicylic doped tetraethoxysilane (SATEOS), composite material by sol-gel method as a new ion exchanger for the removal of Ni(II) from aqueous solution. The fine granular material was prepared by acid catalyzed condensation polymerization through sol-gel mechanism in the presence of cationic surfactant. The material has an ion exchange capacity of 0.64 mequiv./g(dry) for sodium ions, 0.60 mequiv./g(dry) for potassium ions, 1.84 mequiv./g(dry) for magnesium ions, 1.08 mequiv./g(dry) for calcium ions and 1.36 mequiv./g(dry) for strontium ions. Its X-ray diffraction studies suggest that it is crystalline in nature. The material has been characterized by SEM, IR, TGA and DTG so as to identify the various functional groups and ion exchange sites present in this material. Quantum chemical computations at DFT/B3LYP/6-311G (d,p) level on model systems were performed to substantiate the structural conclusions based ion instrumental techniques. Investigations into the elution behaviour, ion exchange reversibility and distribution capacities of this material towards certain environmentally hazardous metal ions are also performed. The material shows good chemical stability towards acidic conditions and exhibits fast elution of exchangeable H(+) ions under neutral conditions. This material shows remarkable selectivity for Ni(II) and on the basis of its Kd value (4×10(2) in 0.01M HClO4) some binary separations of Ni(II) from other metal ions are performed. PMID:23774782

  12. 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.

  13. Advanced composite materials and processes

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.

    1991-01-01

    Composites are generally defined as two or more individual materials, which, when combined into a single material system, results in improved physical and/or mechanical properties. The freedom of choice of the starting components for composites allows the generation of materials that can be specifically tailored to meet a variety of applications. Advanced composites are described as a combination of high strength fibers and high performance polymer matrix materials. These advanced materials are required to permit future aircraft and spacecraft to perform in extended environments. Advanced composite precursor materials, processes for conversion of these materials to structures, and selected applications for composites are reviewed.

  14. Verification of the content, isotopic composition and age of plutonium in Pu-Be neutron sources by gamma-spectrometry

    E-print Network

    Cong Tam Nguyen

    2005-08-29

    A non-destructive, gamma-spectrometric method for verifying the plutonium content of Pu-Be neutron sources has been developed. It is also shown that the isotopic composition and the age of plutonium (Pu) can be determined in the intensive neutron field of these sources by the ``Multi-Group Analysis'' method. Gamma spectra were taken in the far-field of the sample, which was assumed to be cylindrical. The isotopic composition and the age of Pu were determined using a commercial implementation of the Multi-Group Analysis algorithm. The Pu content of the sources was evaluated from the count rates of the gamma-peaks of 239Pu, relying on the assumption that the gamma-rays are coming to the detector parallel to each other. The determination of the specific neutron yields and the problem of neutron damage to the detector are also discussed.

  15. Verification of the content, isotopic composition and age of plutonium in Pu-Be neutron sources by gamma-spectrometry

    E-print Network

    Nguyen, C T

    2006-01-01

    A non-destructive, gamma-spectrometric method for verifying the plutonium content of Pu-Be neutron sources has been developed. It is also shown that the isotopic composition and the age of plutonium (Pu) can be determined in the intensive neutron field of these sources by the ``Multi-Group Analysis'' method. Gamma spectra were taken in the far-field of the sample, which was assumed to be cylindrical. The isotopic composition and the age of Pu were determined using a commercial implementation of the Multi-Group Analysis algorithm. The Pu content of the sources was evaluated from the count rates of the gamma-peaks of 239Pu, relying on the assumption that the gamma-rays are coming to the detector parallel to each other. The determination of the specific neutron yields and the problem of neutron damage to the detector are also discussed.

  16. Aligned Carbon Nanotube Reinforced Silicon Carbide Composites by Chemical Vapor Infiltration

    SciTech Connect

    Gu, Zhan Jun [University of Georgia, Athens, GA; Yang, Ying Chao [University of South Carolina, Columbia; Li, Kai Yuan [University of Georgia, Athens, GA; Tao, Xin Yong [University of South Carolina, Columbia; Eres, Gyula [ORNL; Howe, Jane Y [ORNL; Zhang, Li Tong [Northwestern Polytechnical University, Xi'an, China; Li, Xiao Dong [University of South Carolina, Columbia; Pan, Zhengwei [ORNL

    2011-01-01

    Owing to their exceptional stiffness and strength1 4, carbon nanotubes (CNTs) have long been considered to be an ideal reinforcement for light-weight, high-strength, and high-temperature-resistant ceramic matrix composites (CMCs)5 10. However, the research and development in CNT-reinforced CMCs have been greatly hindered due to the challenges related to manufacturing including poor dispersion, damages during dispersion, surface modification, densification and sintering, weak tube/matrix interfaces, and agglomeration of tubes at the matrix grain boundaries5,11. Here we report the fabrication of high-quality aligned CNT/SiC composites by chemical vapor infiltration (CVI), a technique that is being widely used to fabricate commercial continuous-filament CMCs12 15. Using the CVI technique most of the challenges previously encountered in the fabrication of CNT composites were readily overcome. Nanotube pullouts, an important toughening mechanism for CMCs, were consistently observed on all fractured CNT/SiC samples. Indeed, three-point bending tests conducted on individual CNT/SiC nanowires (diameters: 50 200 nm) using an atomic force microscope show that the CNT-reinforced SiC nanowires are about an order of magnitude tougher than the bulk SiC. The tube/matrix interface is so intimate and the SiC matrix is so dense that a ~50-nm-thick SiC coating can effectively protect the inside nanotubes from being oxidized at 1600 C in air. The CVI method may be extended to produce nanotube composites from a variety of matrix

  17. Moisture Absorption and Desorption of Composite Materials

    Microsoft Academic Search

    Chi-Hung Shen; George S. Springer

    1976-01-01

    Expressions are presented for the moisture distribution and the mois ture content as a function of time of one dimensional homogeneous and composite materials exposed either on one side or on both sides to humid air or to water. The results apply during both moisture absorption and desorption when the moisture content and the temperature of the environ ment are

  18. High-reinforcement-content metal matrix composites

    SciTech Connect

    NONE

    1995-06-01

    This article describes how aluminum-based composites with high volume percentages of nonmetallic reinforcement materials can challenge applications traditionally met by ferrous materials. Discontinuously reinforced metal matrix composites (MMC) have a wide range of potential automotive applications. These extend from structural uses, including wear-resistant components such as disc-brake rotors, through high-specific-stiffness components such as robot arms and disc-brake calipers, to high-specific-strength components such as connecting rods. In addition, composites with silicon carbide (SiC) filler have low density, high thermal conductivity, and low coefficient of thermal expansion (CTE) that makes them useful for controlling temperatures in electronic devices.

  19. Comparison of the structural and chemical composition of two unique micro/nanostructures produced by femtosecond laser interactions on nickel

    SciTech Connect

    Zuhlke, Craig A.; Anderson, Troy P.; Alexander, Dennis R. [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)] [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588 (United States)

    2013-09-16

    The structural and chemical composition of two unique microstructures formed on nickel, with nanoscale features, produced using femtosecond laser surface processing (FLSP) techniques is reported in this paper. These two surface morphologies, termed mounds and nanoparticle-covered pyramids, are part of a larger class of self-organized micro/nanostructured surfaces formed using FLSP. Cross-sections of the structures produced using focused ion beam milling techniques were analyzed with a transmission electron microscope. Both morphologies have a solid core with a layer of nanoparticles on the surface. Energy dispersive X-ray spectroscopy by scanning transmission electron microscopy studies reveal that the nanoparticles are a nickel oxide, while the core material is pure nickel.

  20. Verification of chemical composition of commercially available propolis extracts by gas chromatography-mass spectrometry analysis.

    PubMed

    Czy?ewska, Urszula; Kono?czuk, Joanna; Teul, Joanna; Dr?gowski, Pawe?; Pawlak-Morka, Renata; Sura?y?ski, Arkadiusz; Miltyk, Wojciech

    2015-05-01

    Propolis is a resin that is collected by honeybees from various plant sources. Due to its pharmacological properties, it is used in commercial production of nutritional supplements in pharmaceutical industry. In this study, gas chromatography-mass spectrometry was applied for quality control analysis of the three commercial specimens containing aqueous-alcoholic extracts of bee propolis. More than 230 constituents were detected in analyzed products, including flavonoids, chalcones, cinnamic acids and their esters, phenylpropenoid glycerides, and phenylpropenoid sesquiterpenoids. An allergenic benzyl cinnamate ester was also identified in all tested samples. This analytical method allows to evaluate biological activity and potential allergenic components of bee glue simultaneously. Studies on chemical composition of propolis samples may provide new approach to quality and safety control analysis in production of propolis supplementary specimens. PMID:25198412

  1. Associating Physical and Chemical Properties to Evaluate Buffer Materials by Th and U Sorption

    Microsoft Academic Search

    Yi-Lin Jan; Tzu-Yun Chen; Hwai-Ping Cheng; Chun-Nan Hsu; Chia-Liang Tseng; Yuan-Yaw Wei; Jen-Yan Yang; Cheng-Hsiung Ke; Jui-Tang Chuang; Shi-Ping Teng

    2003-01-01

    The physical and chemical properties of buffer materials to be used for a radwaste disposal repository should be evaluated prior to use. In a conventional approach, independent studies of physical and\\/or chemical characteristics are conducted. This study investigated the relationship between the plastic index (PI) and distribution ratio (Rd) of buffer materials composed of varying ratios of quartz sand and

  2. CARBON FIBRE COMPOSITE MATERIALS PRODUCED BY GAMMA RADIATION INDUCED CURING OF EPOXY RESINS

    SciTech Connect

    Dispenza, C.; Spadaro, G.; Alessi, S. [Dipartimento di Ingegneria Chimica dei Processi e dei Materiali (DICPM), Centro Interdipartimentale sui Materiali Compositi (CIRMAC), Universita di Palermo, Viale delle Scienze 90128, Palermo (Italy)

    2008-08-28

    It is well known that ionizing radiation can initiate polymerization of suitable monomers for many applications. In this work an epoxy difunctional monomer has been used as matrix of a carbon fibre composite in order to produce materials through gamma radiation, for aerospace and advanced automotive applications. Radiation curing has been performed at different absorbed doses and, as comparison, also thermal curing of the same monomer formulations has been done. Furthermore some irradiated samples have been also subjected to a post irradiation thermal curing in order to complete the polymerization reactions. The properties of the cured materials have been studied by moisture absorption isotherms, dynamic mechanical thermal analysis and mechanical flexural tests.

  3. CHARACTERIZATION AND PROPERTIES OF ALUMINUM COMPOSITE MATERIALS PREPARED BY POWDER METALLURGY TECHNIQUES USING CERAMIC SOLID WASTES

    Microsoft Academic Search

    L. Ma. Flores-Vélez; J. Chávez; L. Hernández; O. Domínguez

    2001-01-01

    This work provides preliminary results of aluminum metal matrix composites (MMCs) reinforced with granulated slag (GS) and electric arc furnace dust (EAFD). The present work concerns the synthesis and properties of Al\\/GS and Al\\/EAFD composites based on powder metallurgy techniques. The hardness and compressive strength of the sintering compacts were determined to compare the mechanical properties of the composite material

  4. Chemical analysis and biological testing of materials from the EDS coal liquefaction process: a status report

    SciTech Connect

    Later, D.W.; Pelroy, R.A.; Wilson, B.W.

    1984-05-01

    Representative process materials were obtained from the EDS pilot plant for chemical and biological analyses. These materials were characterized for biological activity and chemical composition using a microbial mutagenicity assay and chromatographic and mass spectrometric analytical techniques. The two highest boiling distillation cuts, as well as process solvent (PS) obtained from the bottoms recycle mode operation, were tested for initiation of mouse skin tumorigenicity. All three materials were active; the crude 800/sup 0 +/F cut was substantially more potent than the crude bottoms recycle PS or 750 to 800/sup 0/F distillate cut. Results from chemical analyses showed the EDS materials, in general, to be more highly alkylated and have higher hydroaromatic content than analogous SRC II process materials (no in-line process hydrogenation) used for comparison. In the microbial mutagenicity assays the N-PAC fractions showed greater activity than did the aliphatic hydrocarbon, hydroxy-PAH, or PAH fractions, although mutagenicity was detected in certain PAH fractions by a modified version of the standard microbial mutagenicity assay. Mutagenic activities for the EDS materials were lower, overall, than those for the corresponding materials from the SRC II process. The EDS materials produced under different operational modes had distinguishable differences in both their chemical constituency and biological activity. The primary differences between the EDS materials studied here and their SRC II counterparts used for comparison are most likely attributable to the incorporation of catalytic hydrogenation in the EDS process. 27 references, 28 figures, 27 tables.

  5. A methodology to reduce error sources in the determination of thin film chemical composition by EDAX

    Microsoft Academic Search

    J. R. Ares; A. Pascual; I. J. Ferrer; C. Sánchez

    2004-01-01

    EDAX is commonly used to determine the chemical composition of thin films. We use this technique to know the stoichiometric ratio of FeS2 films. We have identified three main error sources, which can affect the obtained results and yield mistaken conclusions: (a) EDAX signals from the substrate components; (b) carbon thin film used to protect the reference sample against environmental

  6. Fiber composite materials technology development

    SciTech Connect

    Chiao, T.T.

    1980-10-23

    The FY1980 technical accomplishments from the Lawrence Livermore National laboratory (LLNL) for the Fiber Composite Materials Technology Development Task fo the MEST project are summarized. The task is divided into three areas: Engineering data base for flywheel design (Washington University will report this part separately), new materials evaluation, and time-dependent behavior of Kevlar composite strands. An epoxy matrix was formulated which can be used in composites for 120/sup 0/C service with good processing and mechanical properties. Preliminary results on the time-dependent properties of the Kevlar 49/epoxy strands indicate: Fatigue loading, as compared to sustained loading, drastically reduces the lifetime of a Kevlar composie; the more the number of on-off load cycles, the less the lifetime; and dynamic fatigue of the Kevlar composite can not be predicted by current damage theories such as Miner's Rule.

  7. Variability of the essential oil content and composition of chamomile (Matricaria recutita L.) affected by weather conditions.

    PubMed

    Gosztola, Beáta; Sárosi, Szilvia; Németh, Eva

    2010-03-01

    In our study we examined the variability of the essential oil content and composition of chamomile (Matricaria recutita L.) during three years (2005-2007). Twenty-eight populations of wild origin and 4 registered cultivars ('Soroksári 40', 'Lutea', 'Goral' and 'Bona') were evaluated in open field experiments. It could be established that the experimental populations represented different genetic potential for essential oil accumulation and composition. The best populations of wild growing origin from the Somogy-region and four cultivars produced the highest essential oil contents (above 0.6 g/100g) in each year. Additionally, the quality of the characteristic main compound of the oil determining the "chemotype", according to Schilcher, was found to be stable during the three years period. However, the actual chemosyndroms are significantly influenced by the weather conditions. In the three years' experiment, the moderately warm and relatively wet year of 2006 produced the highest contents of essential oil and also that of its alpha-bisabolol component. Although bisabolol oxide A also showed a high variability through the years, its direct connection with weather conditions could not be proved. A moderate variability was established for the proportions of chamazulene, and the lowest one for bisabolol-oxide B. Considerable genotype-weather interaction was supposed, especially for the essential oil content and for the ratio of bisabolol-oxide A. PMID:20420329

  8. Biochemical composition, energy content and chemical antifeedant and antifoulant defenses of the colonial Antarctic ascidian Distaplia cylindrica

    Microsoft Academic Search

    J. B. McClintock; M. O. Amsler; C. D. Amsler; K. J. Southworth; C. Petrie; B. J. Baker

    2004-01-01

    The colonial ascidian Distaplia cylindrica occurs both as scattered individual colonies or in “gardens” of colonies in fine-grained soft substrata below 20 m depths off Anvers Island along the Antarctic Peninsula. Individual colonies, shaped as tall rod-like cylinders and anchored in the sediments by a bulbous base, may measure up to 7 m in height. D. cylindrica represent a considerable source of

  9. Effects of Annealing on Chemical Composition, Crystallinity, Optical Transmission and Electrical Conductivity of ZnO Thin Films Prepared on Glass Substrates by Chemical Bath Deposition

    Microsoft Academic Search

    Satoshi Kobayashi; Kohei Oshima; Takayuki Sasaki; Nozomu Tsuboi; Futao Kaneko

    2005-01-01

    The effects of annealing on the chemical composition and other properties of ZnO thin films prepared on glass substrates by chemical bath deposition are described. The atomic ratio [Zn]:[O] of the unannealed film measured by electron probe X-ray microanalysis (EPMA) is 45:55, lower than the ideal ratio 50:50. It gradually increases toward the ideal ratio with increasing annealing temperature up

  10. Germanium-on-Silicon Strain Engineered Materials for Improved Device Performance Grown by Chemical Vapor Deposition

    NASA Astrophysics Data System (ADS)

    Bharathan, Jayesh Moorkoth

    The primary goal of this research is to develop a chemical vapor deposition process for growing epitaxial films of germanium on silicon (001) substrates with two-dimensional (2-D) morphology, and a low density of threading dislocations. Growth was carried out in a reduced-pressure chemical vapor deposition (RPCVD) system by a two-step growth technique. An accurate knowledge of elastic constants of thin films is important in understanding the effect of strain on material properties. Residual thermal strain was used to measure the Poisson ratio of Ge films grown on Si(001) substrates, by the sin2Psi method and highresolution x-ray diffraction. The Poisson ratio of the Ge films was measured to be 0.25, compared to the bulk value of 0.27. The result was found to be independent of film thickness and defect density, which confirmed that the strain is associated with the elastic response of the film. The study showed that the use of Poisson ratio instead of bulk compliance values yields a more accurate description of the state of in-plane strain present in the film. The experimentally measured in-plane strain in Ge films was found to be lower than the theoretical calculations based on the differential thermal expansion coefficients of Si and Ge. The mechanism of thermal misfit strain relaxation in epitaxial Ge films grown on Si(001) substrates was investigated by x-ray diffraction, and transmission electron microscopy. Lattice misfit strain associated with Ge/(001)Si mismatched epitaxy is relieved by a network of Lomer edge misfit dislocations during the first step of the growth technique. However, thermal misfit strain energy during growth is relieved by interdiffusion mechanism at the heterointerface. Two SiGe compositions containing 0.5 and 6.0 atomic percent Si were detected that relieve the thermal mismatch strain associated with the two steps of the growth process. This study discusses the importance of interdiffusion mechanism in relieving small misfit strains present during epitaxy. The microstructural characteristics of Ge films were analyzed by x-ray diffraction, atomic force microscopy and transmission electron microscopy. The principal defects in the epitaxial films were determined to be threading dislocations and stacking faults. A unique defect appearing as a line during defect delineation was established to be a wide stacking fault arising from oxygen contamination during RPCVD epitaxy. A decrease in defect density by almost an order of magnitude was observed with increasing film thickness. Germanium films with a thickness of 3.5 mum exhibited the lowest threading dislocation densities of 5 x 106 cm-2. The mechanisms of interactions between threading dislocations has been discussed with the aid of transmission electron microscopy to explain the reduction in the observed threading dislocation density. A strong correlation was obtained between electrical performance of the devices and defect density. Thicker films with the lowest threading dislocation density of 5 x 106 cm-2 also yielded devices with the lowest dark current density of ˜ 5 mA/cm2 (1 V reverse bias) and bulk resistivity of 30 O cm2. All devices showed spectral response of up to 1.61 mum, confirming a strain-induced shrinkage of the direct band gap by approximately 30 meV, which is in good agreement with theoretical models. In summary, the structural, electrical, and optical properties of 2-D Ge films grown on Si(001) substrates by RPCVD has been investigated.

  11. Chemical composition of selected edible nut seeds.

    PubMed

    Venkatachalam, Mahesh; Sathe, Shridhar K

    2006-06-28

    Commercially important edible nut seeds were analyzed for chemical composition and moisture sorption. Moisture (1.47-9.51%), protein (7.50-21.56%), lipid (42.88-66.71%), ash (1.16-3.28%), total soluble sugars (0.55-3.96%), tannins (0.01-0.88%), and phytate (0.15-0.35%) contents varied considerably. Regardless of the seed type, lipids were mainly composed of mono- and polyunsaturated fatty acids (>75% of the total lipids). Fatty acid composition analysis indicated that oleic acid (C18:1) was the main constituent of monounsaturated lipids in all seed samples. With the exception of macadamia, linoleic acid (C18:2) was the major polyunsaturated fatty acid. In the case of walnuts, in addition to linoleic acid (59.79%) linolenic acid (C18:3) also significantly contributed toward the total polyunsaturated lipids. Amino acid composition analyses indicated lysine (Brazil nut, cashew nut, hazelnut, pine nut, and walnut), sulfur amino acids methionine and cysteine (almond), tryptophan (macadamia, pecan), and threonine (peanut) to be the first limiting amino acid as compared to human (2-5 year old) amino acid requirements. The amino acid composition of the seeds was characterized by the dominance of hydrophobic (range = 37.16-44.54%) and acidic (27.95-33.17%) amino acids followed by basic (16.16-21.17%) and hydrophilic (8.48-11.74%) amino acids. Trypsin inhibitory activity, hemagglutinating activity, and proteolytic activity were not detected in the nut seed samples analyzed. Sorption isotherms (Aw range = 0.08-0.97) indicated a narrow range for monolayer water content (11-29 mg/g of dry matter). No visible mold growth was evident on any of the samples stored at Aw < 0.53 and 25 degrees C for 6 months. PMID:16787018

  12. Chemical composition of the continental crust as revealed by studies in East China

    NASA Astrophysics Data System (ADS)

    Shan, Gao; Luo, Ting-Chuan; Zhang, Ben-Ren; Zhang, Hong-Fei; Han, Yin-Wen; Zhao, Zi-Dan; Hu, Yi-Ken

    1998-06-01

    We report abundances of sixty-three major, trace, and rare earth elements in the upper crust in five tectonic units (the interior and southern margin of the North China craton, the North and South Qinling orogenic belts, and the Yangtze craton) of central East China and the study area as a whole. The estimates are based on sampling of 11,451 individual rock samples over an area of 950,000 km 2 , from which 905 large composite samples were prepared and analyzed by thirteen methods. Some of the trace elements (i.e., Ag, As, Ge, Mo, Pd, Pt, Sb, Se, Sn, W) have never been subjected to systematic analysis in previous regional crustal composition studies. The middle, lower, and total crust compositions of the tectonic units are also estimated from studies of exposed crustal cross-sections and granulite xenoliths and by correlation of seismic data from eleven regional seismic refraction profiles with lithologies. The proposed granodioritic total crust composition has the following ratios of element pairs exhibiting similar compatibility, that are identical or close to the primitive mantle values: Zr/Hf = 37, Nb/Ta = 17.5, Ba/Th = 87, K/Pb = 0.12 × 10 4 , Rb/Cs = 25, Ba/Rb = 8.94, Sn/Sm = 0.31, Se/Cd = 1.64, La/As = 10.3, Ce/Sb = 271, Pb/Bi = 57, Rb/Tl = 177, Er/Ag = 52, Cu/Au = 3.2×10 4 , Sm/Mo = 7.5, Nd/W = 40, Cl/Li = 10.8, F/Nd = 21.9, and La/B = 1.8. The ( ) value is calculated at ~5. The upper crust composition is less evolved and higher in TiO 2 , total FeO, Co, Cr, Ni, Sc and V, and lower in Na 2 O, K 2 O and Nb, Ta, Rb, Th, U, and Zr, than previous estimates based on shield samplings. Because usually the uppermost layer of the crust, where mafic volcanics tend to concentrate, has been removed from Precambrian shields, and since our study involves Phanerozoic orogenic belts, the results are suggested to be better representative of the upper crust in a general sense. Trace elements associated with mineralization (e.g., B, Cl, Se, As, Bi, Pd, W, Th, Cs, Ta, Tl, Hg, Au, and Pb) show considerable inter-unit variations by a factor of 2-5 in the upper crust. In addition, the North Qinling paleoactive margin is characterized by anomalous enrichment in Th, U, and Pb in particular and has a marked lower value (3.3) compared to the two cratons and the South Qinling paleopassive margin ( = 4.5-6.2). Each tectonic unit has a relatively homogenous middle crust composition which is broadly similar to the composition of the total crust. The lower crust in East China can be divided into two layers both seismically and chemically. The upper lower crust is characterized by Vp = 6.7 km s -1 and an intermediate composition and the lowermost crust by Vp = 7.1 km s -1 and a mafic composition. The bulk lower crust is still intermediate in composition with 58% SiO 2 due to the dominance of the upper lower crust. P-wave velocities of both the lower and total crusts in East China are slower by 0.2-0.4 km s -1 compared to various global estimates. Correspondingly, the total crust shows an more evolved composition and is characterized by a significant negative Eu anomaly (Eu/Eu * = 0.80), low (10.4), and high (3.0) ratios. The obtained SiO 2 is 64% on a volatile-free basis. The near arc magma ratio implies that intraplate crustal growth contributes < 10% of the continental crust. The relative deficits in Eu, Sr, and transition metals (Cr, Ni, Co, V, and Ti) in the derived crustal compositions of East China, along with slower crustal velocity and thin crustal thickness for the Paleozoic to Mesozoic Qinling-Dabie-Sulu orogenic belt, strongly suggest that lower crust delamination of eclogites, as represented by those from the Dabie-Sulu belt, had played an important role in modification of the East China crust during the Phanerozoic era.

  13. Chemical composition of the continental crust as revealed by studies in East China

    NASA Astrophysics Data System (ADS)

    Gao, Shan; Luo, Ting-Chuan; Zhang, Ben-Ren; Zhang, Hong-Fei; Han, Yin-wen; Zhao, Zi-Dan; Hu, Yi-Ken

    1998-06-01

    We report abundances of sixty-three major, trace, and rare earth elements in the upper crust in five tectonic units (the interior and southern margin of the North China craton, the North and South Qinling orogenic belts, and the Yangtze craton) of central East China and the study area as a whole. The estimates are based on sampling of 11,451 individual rock samples over an area of 950,000 km 2, from which 905 large composite samples were prepared and analyzed by thirteen methods. Some of the trace elements (i.e., Ag, As, Ge, Mo, Pd, Pt, Sb, Se, Sn, W) have never been subjected to systematic analysis in previous regional crustal composition studies. The middle, lower, and total crust compositions of the tectonic units are also estimated from studies of exposed crustal cross-sections and granulite xenoliths and by correlation of seismic data from eleven regional seismic refraction profiles with lithologies. The proposed granodioritic total crust composition has the following ratios of element pairs exhibiting similar compatibility, that are identical or close to the primitive mantle values: Zr/Hf = 37, Nb/Ta = 17.5, Ba/Th = 87, K/Pb = 0.12 × 10 4, Rb/Cs = 25, Ba/Rb = 8.94, Sn/Sm = 0.31, Se/Cd = 1.64, La/As = 10.3, Ce/Sb = 271, Pb/Bi = 57, Rb/Tl = 177, Er/Ag = 52, Cu/Au = 3.2×10 4, Sm/Mo = 7.5, Nd/W = 40, Cl/Li = 10.8, F/Nd = 21.9, and La/B = 1.8. The ? ( 238U/ 204Pb) value is calculated at ˜5. The upper crust composition is less evolved and higher in TiO 2, total FeO, Co, Cr, Ni, Sc and V, and lower in Na 2O, K 2O and Nb, Ta, Rb, Th, U, and Zr, than previous estimates based on shield samplings. Because usually the uppermost layer of the crust, where mafic volcanics tend to concentrate, has been removed from Precambrian shields, and since our study involves Phanerozoic orogenic belts, the results are suggested to be better representative of the upper crust in a general sense. Trace elements associated with mineralization (e.g., B, Cl, Se, As, Bi, Pd, W, Th, Cs, Ta, Tl, Hg, Au, and Pb) show considerable inter-unit variations by a factor of 2-5 in the upper crust. In addition, the North Qinling paleoactive margin is characterized by anomalous enrichment in Th, U, and Pb in particular and has a marked lower ? value (3.3) compared to the two cratons and the South Qinling paleopassive margin (? = 4.5-6.2). Each tectonic unit has a relatively homogenous middle crust composition which is broadly similar to the composition of the total crust. The lower crust in East China can be divided into two layers both seismically and chemically. The upper lower crust is characterized by Vp = 6.7 km s -1 and an intermediate composition and the lowermost crust by Vp = 7.1 km s -1 and a mafic composition. The bulk lower crust is still intermediate in composition with 58% SiO 2 due to the dominance of the upper lower crust. P-wave velocities of both the lower and total crusts in East China are slower by 0.2-0.4 km s -1 compared to various global estimates. Correspondingly, the total crust shows an more evolved composition and is characterized by a significant negative Eu anomaly (Eu/Eu? = 0.80), low Sr/Nd (10.4), and high La/Nb (3.0) ratios. The obtained SiO 2 is 64% on a volatile-free basis. The near arc magma La/Nb ratio implies that intraplate crustal growth contributes <10% of the continental crust. The relative deficits in Eu, Sr, and transition metals (Cr, Ni, Co, V, and Ti) in the derived crustal compositions of East China, along with slower crustal velocity and thin crustal thickness for the Paleozoic to Mesozoic Qinling-Dabie-Sulu orogenic belt, strongly suggest that lower crust delamination of eclogites, as represented by those from the Dabie-Sulu belt, had played an important role in modification of the East China crust during the Phanerozoic era.

  14. Nondestructive determination of oil content and fatty acid composition in perilla seeds by near-infrared spectroscopy.

    PubMed

    Kim, Kwan Su; Park, Si Hyung; Choung, Myoung Gun

    2007-03-01

    Near-infrared reflectance spectroscopy (NIRS) was used as a rapid and nondestructive method to determine the oil content and fatty acid composition in intact seeds of perilla [Perilla frutescens var. japonica (Hassk.) Hara] germplasms in Korea. A total of 397 samples (about 2 g of intact seeds) were scanned in the reflectance mode of a scanning monochromator, and the reference values for the oil content and fatty acid composition were measured by gravimetric method and gas-liquid chromatography, respectively. Calibration equations for oil and individual fatty acids were developed using modified partial least-squares regression with internal cross validation (n = 297). The equations for oil and oleic and linolenic acid had lower standard errors of cross-validation (SECV), higher R2 (coefficient of determination in calibration), and higher ratio of unexplained variance divided by variance (1-VR) values than those for palmitic, stearic, and linoleic acid. Prediction of an external validation set (n = 100) showed significant correlation between reference values and NIRS estimated values based on the standard error of prediction (SEP), r2 (coefficient of determination in prediction), and the ratio of standard deviation (SD) of reference data to SEP. The models for oil content and major fatty acids, oleic and linolenic acid, had relatively higher values of SD/SEP(C) and r2 (more than 3.0 and 0.9, respectively), thereby characterizing those equations as having good quantitative information, whereas those of palmitic, stearic, and linoleic acid had lower values (below 2.0 and 0.7, respectively), unsuitable for screening purposes. The results indicated that NIRS could be used to rapidly determine oil content and fatty acid composition (oleic and linolenic acid) in perilla seeds in the breeding programs for development of high-quality perilla oil. PMID:17288449

  15. Synthesis and characteristics of form-stable n-octadecane/expanded graphite composite phase change materials

    NASA Astrophysics Data System (ADS)

    Li, Hui; Liu, Xu; Fang, Gui-Yin

    2010-09-01

    N-octadecane/expanded graphite composite phase-change materials were prepared by absorbing liquid n-octadecane into the expanded graphite. The n-octadecane was used as the phase-change material for thermal energy storage, and the expanded graphite acted as the supporting material. Fourier transformation infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal diffusivity measurement were used to determine the chemical structure, crystalline phase, microstructure and thermal diffusivity of the composite phase-change materials, respectively. The thermal properties and thermal stability were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The DSC results indicated that the composite phase-change materials exhibited the same phase-transition characteristics as the n-octadecane and their latent heat increased with the n-octadecane content in composite phase-change materials. The SEM results showed that the n-octadecane was well absorbed in the porous network of the expanded graphite, and there was no leakage of the n-octadecane from the composites even when it was in the molten state.

  16. Precise Determination of Thicknesses of Multilayer Polyethylene Composite Materials by Terahertz Time-Domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Palka, Norbert; Krimi, Soufiene; Ospald, Frank; Miedzinska, Danuta; Gieleta, Roman; Malek, Marcin; Beigang, Rene

    2015-06-01

    The multilayer structure of an ultra-high molecular weight polyethylene (UHMWPE) composite material was investigated in the terahertz (THz) spectral range by means of time-domain spectroscopy (TDS) technique. Such structures consist of many alternating layers of fibers, each being perpendicular to the other and each having a thickness of about 50 ?m. Refractive indices of two composite samples and of a sample composed of four single layers (plies) having the same fiber orientation were determined for two orthogonal orientations of the electric field in a transmission TDS system. The birefringence of a single layer was measured, and the origin of this phenomenon is discussed. Using the TDS system in reflection, the formation of many pulses shifted in time was observed originating from reflections from interfaces of successive layers caused by the periodic modulation of the refractive index along the propagation of the THz radiation. This phenomenon is theoretically described and simulated by means of a transfer matrix method (TMM). A time-domain fitting procedure was used to determine thicknesses of all layers of the composite material. The reconstructed waveform based on the optimized thicknesses shows very good agreement with the measured waveform, with typical differences between measurements and simulations between 3 and 7 ?m (depending on the sample). As a result, we were able to determine the thicknesses of all layers of two multilayer (~200 plies) structures by means of the reflection TDS technology with high accuracy.

  17. Determination of natural radionuclides content in some building materials in Nigeria by gamma-ray spectrometry.

    PubMed

    Ademola, J A

    2008-01-01

    This paper presents the findings of a study undertaken to determine the natural radioactivity present in some building materials in Nigeria using a gamma-ray spectrometer with a hyper pure germanium detector. A total of 118 samples of commonly used building materials were collected from manufacturers and suppliers of these materials. The mean radioactivity concentrations measured in the different building materials varied from 9.4 to 62.9, 1.3 to 88.4, and 21.5 to 762.4 Bq kg(-1), respectively, for 226Ra, 232Th, and 40K. The average contents of 226Ra, 232Th, and 40K for all the samples were 36.3, 46.5, and 320.9 Bq kg(-1), respectively, lower than the world average for building materials (50, 50, and 500 Bq kg(-1)). The calculated mean radium equivalent activity and external and internal hazard indices for the entire sample were lower than United Nation Scientific Committee on the Effects of Atomic Radiation recommended limits and comparable with results of similar studies undertaken in other countries. The mean annual gonadal equivalent doses of some of the samples were higher than the world average value for soil. PMID:18091150

  18. Shock-Induced Chemical Reactions in Structural Energetic Materials

    NASA Astrophysics Data System (ADS)

    Narayanan, V.; Lu, X.; Hanagud, S.

    2006-07-01

    Various powder mixtures like intermetallic mixtures and mixtures of metals and metal oxides have potential applications as structural energetic materials (SEMs). Technologies of varying the compositions and the powder sizes and their synthesis are being investigated to provide multiple desirable characteristics, like high strength and high energy content. In this paper, we formulate a model for SEMs for their application in shock conditions, in the framework of nonequilibrium thermodynamics and continuum mechanics. A mixture of Al and KClO4 is selected as the example for SEMs. A mixture, pore collapse and chemical reaction model are included. By adapting energy barriers for reaction as a function of temperature, particle size and pressure and introducing a relaxation mechanism in the reaction model, a shock-induced chemical reaction model is developed. The variation of the relaxation mechanism is also modeled. The initiation and propagation of chemical reactions are studied. The time and spatial dependency of chemical reaction on the shock wave conditions are investigated.

  19. Non-destructive testing of composite materials by means of active thermography-based tools

    NASA Astrophysics Data System (ADS)

    Lizaranzu, Miguel; Lario, Alberto; Chiminelli, Agustín; Amenabar, Ibán

    2015-07-01

    Infrared analysis tools are nowadays widely used for the non-destructive testing of components made up in composite materials, belonging to many different industrial sectors. Being a non-contact method, its capability for the inspection of large areas in short periods of time justifies the great number of works and technical studies that can be found in this field. The growing interest in the technique is also supported by the development, during recent years, of increasingly powerful equipment and data analysis tools. In order to establish a base of knowledge to assist defect identification in real components inspections, the design and manufacturing of inspection samples including controlled defects, is a frequently used strategy. This paper deals with the analysis, by means of transient active thermography, of a set of inspection patterns made out of different composite materials and configurations that can be found in the wind turbine blade manufacturing industry. The design and manufacturing of these patterns are described, including different types of representative defects, stack configurations and composite manufacturing techniques. Reference samples are then inspected by means of active thermography analysis tools and the results obtained are discussed.

  20. Hugoniot Analysis of Composite Materials

    Microsoft Academic Search

    S. K. Garg; J. W. Kirsch

    1971-01-01

    A generalized set of conservation equations (i.e., the Hugoniot relations) across a disturbance propagating through a composite material with a steady velocity are derived within the framework of the Theory of Inter acting Continua. By providing a rational basis for comparison, the analysis clarifies the differences between the earlier studies in this field. In addition, the present development of the

  1. Method to fabricate layered material compositions

    DOEpatents

    Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM)

    2002-01-01

    A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

  2. Elastomer actuators: systematic improvement in properties by use of composite materials

    NASA Astrophysics Data System (ADS)

    Molberg, Martin; Leterrier, Yves; Plummer, Christopher J. G.; Löwe, Christiane; Opris, Dorina M.; Clemens, Frank; Månson, Jan-Anders E.

    2010-04-01

    Dielectric elastomer actuators (DEAs) have attracted increasing attention over the last few years owing to their outstanding properties, e.g. their large actuation strains, high energy density, and pliability, which have opened up a wide spectrum of potential applications in fields ranging from microengineering to medical prosthetics. There is consequently a huge demand for new elastomer materials with improved properties to enhance the performance of DEAs and to overcome the limitations associated with currently available materials, such as the need for high activation voltages and the poor long-term stability. The electrostatic pressure that activates dielectric elastomers can be increased by higher permittivity of the elastomer and thus may lead to lower activation voltages. This has led us to consider composite elastomeric dielectrics based on thermoplastic elastomers or PDMS, and conductive polyaniline or ceramic (soft doped PZT) powder fillers. The potential of such materials and strategies to counter the adverse effects of increased conductivity and elastic modulus are discussed.

  3. Vector diagram of the chemical compositions of tektites and earth lavas

    NASA Technical Reports Server (NTRS)

    Kvasha, L. G.; Gorshkov, G. S.

    1978-01-01

    The chemical compositions of tektites and various volcanic glasses, similar in composition to tektites are compared by a petrochemical method. The advantage of the method is that a large number of chemical analyses of igneous rocks can be graphically compared with the help of vectors, plotted in relation to six parameters. These parameters, calculated from ratios of the main oxides given by silicate analysis, reflect the chief characteristics of igneous rock. Material for the study was suppled by data from chemical analysis characterizing tektites of all known locations and data from chemical analyses of obsidians similar in chemical composition to tektites of various petrographical provinces.

  4. [Influence of particle sizes and content of effective compositions of Panax notoginseng powders crashing by superfine somminution technique].

    PubMed

    Wang, Yan-Ping; Liu, Yu-Ling; Yang, Li-Xin; Xu, Ya; Zhao, Li; Zhang, Xiao-Li; Li, Hui

    2014-04-01

    In this study, superfine comminution technique was applied to destroy the cell wall of the Panax notoginseng, and then the influence of the particle sizes and the content of effective composition of the P. notoginseng powders were learned, comparing with the common powders. Superfine comminution technique was used for 0.5, 1, 1.5, 2 h, respectively and the particle sizes, unifirmity were regarded as the evaluation index. Then, the sizes of the powders was measured that were crashed with different time by Malvern Mastersizer 2000 + Scricco 2000 and the total content of ginsenoside Rg1, ginsenoside Rb1, notoginsenoside R1 in the superfine powder of P. notoginseng were determined by HPLC-ELSD. Finally, the powder that crashed for two hours possess the more uniform in sizes that is at cell level, D50 is about 9.599 microm, the size distribution was presented as one peak, the other three samples were two peaks. The total content of the three saponins in the four samples that crashed for 0.5, 1, 1.5, 2 h by superfine comminution technique were 7.7%, 7.5%, 7.5%, 8.3%. However, the total content of the three ingredients in the common powder was 5.0%. This investigation indicated that superfine comminution technique has remarkable effect on particle size and uniformity of the common powder of P. notoginseng. By comparing the superfine powder and common powder, it was found that the method obviously improved the total content of the saponins and provided a basis for reducing dosage of notoginseng in clinical application, but the content and the crashed time were not the linear relationship. The crashed time can be chosen by combining with the demand partical sizes in the production. PMID:25039177

  5. Chemical composition of leaf extracts of Stevia rebaudiana Bertoni grown experimentally in Vojvodina

    Microsoft Academic Search

    BILJANA F. ABRAMOVI?; Trg D. Obradovi?a

    2008-01-01

    The chemical composition of leaf extracts of Stevia rebaudiana Ber- toni, grown for the first time on an experimental field near Zrenjanin, was examined by GC-MS. The tested plant material was harvested in September of 2002. To analyze the chemical composition of the lipophilic components of the plant leaves, essential oils and ethyl acetate extract were isolated. Qualitative analysis of

  6. Hydrogen storage in different carbon materials: Influence of the porosity development by chemical activation

    NASA Astrophysics Data System (ADS)

    Jiménez, Vicente; Ramírez-Lucas, Ana; Sánchez, Paula; Valverde, José Luís; Romero, Amaya

    2012-01-01

    The hydrogen adsorption capacity of different types of carbon nanofibers (platelet, fishbone and ribbon) and amorphous carbon have been measured as a function of pressure and temperature. The results showed that the more graphitic carbon materials adsorbed less hydrogen than more amorphous materials. After a chemical activation process, the hydrogen storage capacities of the carbon materials increased markedly in comparison with the non-activated ones. BET surface area of amorphous carbon increased by a factor of 3.5 and the ultramicropore volume doubled, thus increasing the hydrogen adsorption by a factor of 2. However, BET surface area in platelet CNFs increased by a factor of 3 and the ultramicropore volume by a factor of 6, thus increasing the hydrogen storage by a factor of 4.5. The dependency of hydrogen storage capacity of carbon materials on the BET surface area was evaluated using both a condensation model and experimental results. Comparison of data suggests that the hydrogen adsorption capacity clearly depends on the pore structure and so, on the accessibility to the internal surface.

  7. Statistical evaluation of the influence of several sample pretreatment methods on the mercury content detectable by chemical analysis of contaminated soil samples under practical conditions

    Microsoft Academic Search

    W. Rasemann; U. Seltmann; M. Hempel

    1995-01-01

    The estimation of the environmental risk of contaminated sites caused by hazardous components may be obtained, for instance, by means of a soil survey. There unavoidable errors by sampling, sample preparation and chemical analysis occur. Furthermore, in case of mercury contaminations, the mercury content detectable by chemical analysis can be falsified, if between sampling, on the one hand, and sample

  8. Joining of polymer composite materials

    SciTech Connect

    Magness, F.H.

    1990-11-01

    Under ideal conditions load bearing structures would be designed without joints, thus eliminating a source of added weight, complexity and weakness. In reality the need for accessibility, repair, and inspectability, added to the size limitations imposed by the manufacturing process and transportation/assembly requirements mean that some minimum number of joints will be required in most structures. The designer generally has two methods for joining fiber composite materials, adhesive bonding and mechanical fastening. As the use of thermoplastic materials increases, a third joining technique -- welding -- will become more common. It is the purpose of this document to provide a review of the available sources pertinent to the design of joints in fiber composites. The primary emphasis is given to adhesive bonding and mechanical fastening with information coming from documentary sources as old as 1961 and as recent as 1989. A third, shorter section on composite welding is included in order to provide a relatively comprehensive treatment of the subject.

  9. Nonlinear Dynamic Properties of Layered Composite Materials

    SciTech Connect

    Andrianov, Igor V.; Topol, Heiko; Weichert, Dieter [Institute of General Mechanics, RWTH Aachen University, Termplergraben 64, Aachen, D-52062 (Germany); Danishevs'kyy, Vladyslav V. [Prydniprovs'ka State Academy of Civil Engineering and Architecture, Dnipropetrovs'k, Chernishevs'kogo 24a, UA-49600 (Ukraine)

    2010-09-30

    We present an application of the asymptotic homogenization method to study wave propagation in a one-dimensional composite material consisting of a matrix material and coated inclusions. Physical nonlinearity is taken into account by considering the composite's components as a Murnaghan material, structural nonlinearity is caused by the bonding condition between the components.

  10. Chemical characterization of torbanites by transmission micro-FTIR spectroscopy: Origin and extent of compositional heterogeneities

    NASA Astrophysics Data System (ADS)

    Landais, Patrick; Rochdi, Aïcha; Largeau, Claude; Derenne, Sylvie

    1993-06-01

    Four Permian to Carboniferous torbanites of various geographical origins were examined by transmission micro-FTIR spectroscopy on doubly polished thin sections (10-25 ?m). Several types of heterogeneities (different types of organic matrix; yellow and orange Botryococcus braunii colonies) were identified and chemically characterized. Important differences were noted between the organic constituents of the matrix and the algal bodies, regarding the intensity of OH, C?O, and aromatic C?C absorptions. The previous IR studies of torbanites on bulk samples therefore afforded substantially biased information on the composition of B. braunii fossil colonies, on their oil potential, and on the maturity of such kerogens. Micro-FTIR spectra indicate that the organic matrix corresponds neither to an extensive breaking up of colonies nor to humic substances. This matrix is highly heterogeneous; two types were identified in the Autun sample (chiefly corresponding to degraded algal and bacterial constituents, respectively). A precise characterization of the organic matrix was made difficult, however, in Pumpherston torbanite, due to intimate mixing with minerals. The co-occurrence of yellow and orange colonies, with contrasted micro-FTIR features, in Autun torbanite neither reflects radiolysis processes nor differences in maturation and/or source algae. A specific spatial relation was observed between these two types of algal bodies and the organo-mineral matrix, thus revealing differences in colony microenvironment after deposition. The orange colonies are likely derived, in agreement with their micro-FTIR spectra and their spatial correlation with the matrix, from sedimentological and/or matrix-catalysed diagenetic transformations of some yellow colonies. This first application of micro-FTIR to kerogens confirmed the utility of this nondestructive, in situ pin-point method. Although torbanites have been extensively studied, all the analytical methods so far used only provided bulk information. Further insight into torbanite composition, origin and evolution can be obtained via micro-FTIR spectroscopy.

  11. Comment on 'Content and isotopic composition of sulphur in ultramafic xenoliths from central Asia' by D. A. Ionov, J. Hoefs, K. H. Wedepohl and U. Wiechert

    Microsoft Academic Search

    J. P. Lorand

    1993-01-01

    In a recent paper, Ionov et al. reported sulfur concentrations ranging between 6 and 26 ppm (average 18 ppm) for a suite of 90 basalt-borne spinel and garnet peridotite xenoliths from central Asia. They conclude that the sulfur content of the xenolith source region in the upper mantle is typically 20-50 ppm. Previous determinations on compositionally similar Iherzolitic material from

  12. Utilization of composite materials by the US Army: A look ahead

    NASA Technical Reports Server (NTRS)

    Chait, Richard

    1992-01-01

    An overview of the use of composite materials in the Army is given. Important efforts to document design information, supporting research, and some national applications for composite materials are given. The use of Kevlar fiber in both vests and helmets for the soldier is outlined. The advantages of using fiberglass in the hull of the Bradley fighting ground vehicle is given. The full potential of composite materials is realized in the recently awarded LH Comanche RAH-66 program. The use of composites for application to rocket motor uses, wings, fins, and casings is under development. Because of the uncertain funding profile, it is more important than ever that technology planning provide the basis for effective prioritization and leveraging of the tech base efforts involving advanced materials.

  13. A TGA technique for determining graphite fiber content in epoxy composites

    Microsoft Academic Search

    R. Y. Yee; T. S. Stephens

    1996-01-01

    A new technique has been developed to measure the fiber content of graphite fiber-reinforced polymer matrix composites. This new method requires less material and less time than the standard matrix digestion method. With data for the densities of the matrix, fiber, and composite, the method can be used to calculate fiber and void volumes. The new method was verified by

  14. Chemical comparisons of liquid fuel produced by thermochemical liquefaction of various biomass materials

    SciTech Connect

    Russell, J.A.; Molton, P.M.; Landsman, S.D.

    1980-12-01

    Liquefaction of biomass in aqueous alkali at temperatures up to 350/sup 0/C is an effective way to convert solid wastes into liquid fuels. The liqefaction oils of several forms of biomass differing in proportions of cellulose, hemi-cellulose, lignin, protein, and minerals were studied and their chemical composition compared. It was that the proportions of chemical components varied considerably depending on the type of biomass liquefied. However, all the oils, even those produced from cellulose, had similar chemical characteristics due to the presence of significant quantities of phenols. These phenols are at least partially responsible for the corrosivity and viscosity commonly associated with biomass oils. The differences in chemical component distribution in the various biomass oils might successfully be exploited if the oil is to be used as a chemical feedstock. If the oil is to be used as a fuel, however, then reaction conditions will be a more important consideration than the source of biomass.

  15. Development of rice husks-plastics composites for building materials.

    PubMed

    Choi, Nak-Woon; Mori, Ippei; Ohama, Yoshihiko

    2006-01-01

    In this paper, a new effective recycling method for rice husks and waste expanded polystyrene is developed by using a combination of both wastes. A styrene solution of waste expanded polystyrene is used as a binder for rice husks-plastics composites. The composites are prepared with various mix proportions by a hot press molding method, and tested for apparent density, water absorption, expansion in thickness, and dry and wet flexural strengths. From the test results, the apparent density of the composites is increased with increasing binder content and filler-binder ratio. Their flexural strength and wet flexural strengths reach maximums at a binder content of 30.0% and a filler-binder ratio of 1.0. Their water absorption and expansion in thickness are decreased with increasing binder content and filler-binder ratio. Since the composites have a high flexural strength and water resistance, their uses as building materials are expected. PMID:16256327

  16. APPLICATION OF TIME-DOMAIN NUCLEAR MAGNETIC RESONANCE TO QUANTIFY OIL CONTENT IN STARCH-OIL COMPOSITES PREPARED BY EXCESS STEAM JET-COOKING

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stable dispersions of starch-oil composites can be obtained by excess steam jet-cooking aqueous slurries of starch and hydrophobic materials such as vegetable oils. These composites consist of uniformly suspended starch-coated oil droplets (1-10 micrometers in diameter). These composites can conta...

  17. Damping behavior of continuous fiber\\/metal composite materials by the free vibration method

    Microsoft Academic Search

    E. C. Botelho; A. N. Campos; E. de Barros; L. C. Pardini; M. C. Rezende

    2005-01-01

    Fiber metal laminates (FML) offer significant improvements over current available materials for aircraft structures due to their excellent mechanical characteristics and relatively low density. Non-destructive testing techniques are being used in the characterization of composite materials. Among these, vibration testing is one of the most used tools because it allows the determination of the mechanical properties. In this work, the

  18. Chemical processing of lunar materials

    NASA Technical Reports Server (NTRS)

    Criswell, D. R.; Waldron, R. D.

    1979-01-01

    The paper highlights recent work on the general problem of processing lunar materials. The discussion covers lunar source materials, refined products, motivations for using lunar materials, and general considerations for a lunar or space processing plant. Attention is given to chemical processing through various techniques, including electrolysis of molten silicates, carbothermic/silicothermic reduction, carbo-chlorination process, NaOH basic-leach process, and HF acid-leach process. Several options for chemical processing of lunar materials are well within the state of the art of applied chemistry and chemical engineering to begin development based on the extensive knowledge of lunar materials.

  19. Extinction characterization of soot produced by laser ablating carbon fiber composite materials in air flow

    NASA Astrophysics Data System (ADS)

    Liu, Weiping; Ma, Zhiliang; Zhang, Zhenrong; Zhou, Menglian; Wei, Chenghua

    2015-05-01

    In order to research the dynamic process of energy coupling between an incident laser and a carbon fiber/epoxy resin composite material, an extinction characterization analysis of soot, which is produced by laser ablating and located in an air flow that is tangential to the surface of the composite material, is carried out. By the theory analyses, a relationship of mass extinction coefficient and extinction cross section of the soot is derived. It is obtained that the mass extinction coefficients of soot aggregates are the same as those of the primary particles when they contain only a few primary particles. This conclusion is significant when the soot is located in an air flow field, where the generations of the big soot aggregates are suppressed. A verification experiment is designed. The experiment employs Laser Induced Incandescence technology and laser extinction method for the soot synchronization diagnosis. It can derive a temporal curve of the mass extinction coefficient from the soot concentration and laser transmittance. The experiment results show that the mass extinction coefficient becomes smaller when the air flow velocity is higher. The reason is due to the decrease of the scatter effects of the soot particles. The experiment results agree with the theory analysis conclusion.

  20. Fatigue Crack and Porosity Measurement in Composite Materials by Thermographic and Ultrasonic Methods

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Russell, Samuel S.; Suits, Michael W.; Workman, Gary L.

    2003-01-01

    Contents include the following: 1. Purpose. Detect thermo-mechanically induced intra-ply fatigue microcracking and manufactured porosity in unlined composite pressure vessels. 2. Defect descriptions. Porosity, microcracking. 3. Thermography. Overview of technique. Strengths and Weaknesses. Examples of its use for porosity detection. 4. Resonant ultrasound spectroscopy. Overview of technique. Strengths and Weaknesses. Examples of its use for microcracking detection. Conclusions.

  1. Chemical vapor deposition and infiltration processes of carbon materials

    Microsoft Academic Search

    P Delhaes

    2002-01-01

    The chemical vapor deposition (CVD) and the chemical vapor infiltration (CVI) processes of carbon materials are reviewed starting from the historical aspects and including the latest developments in the preparation of C\\/C composites. Our presentation is based on an analysis of the different types of reactors, of the composite materials with different types of pyrocarbon as matrices and a comparison

  2. Collagen immobilized PVA hydrogel-hydroxyapatite composites prepared by kneading methods as a material for peripheral cuff of artificial cornea

    Microsoft Academic Search

    Hisatoshi Kobayashi; Masabumi Kato; Tetsushi Taguchi; Toshiyuki Ikoma; Hideyuki Miyashita; Shigeto Shimmura; Kazuo Tsubota; Junzo Tanaka

    2004-01-01

    In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp

  3. Health, safety and environmental requirements for composite materials

    NASA Technical Reports Server (NTRS)

    Hazer, Kathleen A.

    1994-01-01

    The health, safety and environmental requirements for the production of composite materials are discussed. The areas covered include: (1) chemical identification for each chemical; (2) toxicology; (3) industrial hygiene; (4) fire and safety; (5) environmental aspects; and (6) medical concerns.

  4. New chemically selective optical materials for waveguide sensors

    NASA Astrophysics Data System (ADS)

    Gao, Letian; Shi, Yining; Slaterbeck, Andrew F.; Seliskar, Carl J.; Heineman, William R.

    1998-03-01

    Two new series of chemically-selective optical materials have been made and tested on chemical sensor. One new series of materials was based on polymer blending in a host of glutaraldehyde cross-linked poly(vinyl alcohol). Chemically- selective dopants in this host demonstrate property- selective separations of chemicals from mixtures. We have optimized the composition, optical properties and the coating procedures for several specific blends for optical sensing. These blends have clear UV and visible spectral regions for direct spectroscopic sensing and they are excellent absorber of many inorganic and organic charged species from aqueous environments. A second new series consists of polyelectrolyte containing silica composites prepared by sol-gel processing. The thickness of spin-coated films of these materials on glass can be varied from 0.1 micrometers to 4 micrometers . These materials are ion exchangeable and less brittle than the parent silica substrate due to the incorporation of the organic polyelectrolyte. These new composites retain the nano-scale porosity and optical transparency into the UV of the parent silica sol-gel processed glasses making them attractive host matrices for the immobilization of a variety of chemical reagents. Results obtained with film-clad sensors from both new series of materials are presented.

  5. Variation in Miscanthus chemical composition and implications for conversion by pyrolysis and thermo-chemical bio-refining for fuels and chemicals

    Microsoft Academic Search

    E. M. Hodgson; D. J. Nowakowski; I. Shield; A. Riche; A. V. Bridgwater; J. C. Clifton-Brown; I. S. Donnison

    2011-01-01

    Different species and genotypes of Miscanthus were analysed to determine the influence of genotypic variation and harvest time on cell wall composition and the products which may be refined via pyrolysis. Wet chemical, thermo-gravimetric (TGA) and pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS) methods were used to identify the main pyrolysis products and determine the extent to which genotypic differences in cell wall

  6. Chemical and isotopic compositions of bottled waters sold in Korea: chemical enrichment and isotopic fractionation by desalination.

    PubMed

    Kim, Go-Eun; Ryu, Jong-Sik; Shin, Woo-Jin; Bong, Yeon-Sik; Lee, Kwang-Sik; Choi, Man-Sik

    2012-01-15

    A total of 54 Korean bottled waters were investigated to characterize their origins and types using elemental and isotopic composition, as well as to identify elemental and isotopic changes in desalinated marine water that arise due to desalination. The different types of bottled water displayed a wide pH range (3.42 to 7.21). The elemental compositions of still and sparkling waters were quite similar, whereas desalinated marine water was clearly distinguished by its high concentrations of Ca, Mg, B, and Cl. In addition, desalinated marine water had much higher isotope ratios of oxygen and hydrogen (-0.5 and -2‰, respectively) than still and sparkling waters (-8.4 and -57‰). The elemental composition of desalinated marine water was adjusted through post-treatment procedures; in particular, boron was greatly enriched during desalination processes. The carbon isotope compositions of dissolved inorganic carbon (?(13)C(DIC) values) varied widely according to the origins of the bottled waters (-25.6 to -13.6‰ for still water, -31.2 to -26.7‰ for sparkling water, and -24.1 to -6.3‰ for desalinated marine water). This indicates that carbon isotopes in dissolved inorganic carbon are significantly fractionated by desalination processes and re-modified through post-treatment procedures. The results suggest that combined elemental and stable isotopic tracers are useful for identifying the origin of bottled water, verifying elemental and isotopic modifications during desalination processes, and characterizing various water types of bottled waters. PMID:22215574

  7. Mechanics of composite materials

    Microsoft Academic Search

    G. J. Dvorak; N. Laws

    1988-01-01

    This book contains the following papers: crack growth resistance of TiBâ particulate\\/SiC matrix composite; constitutive relations of flexible composites under elastic deformation; determination of two kinds of composite plasticity: inclusions plastic vs. matrix plastic; 3-D analysis of transient interlaminar thermal stress of laminated composites; effect of seawater on the fracture toughness of pultruded rods; evaluation of new failure criterion for

  8. Chemical Composition, Modulatory Bacterial Resistance and Antimicrobial Activity of Essential Oil the Hyptis martiusii Benth by Direct and Gaseous Contact

    PubMed Central

    de Oliveira, Allan Demetrius Leite; Galvao Rodrigue, Fabiola Fernandes; Douglas Melo Coutinho, Henrique; da Costa, Jose Galberto Martins; de Menezes, Irwin Rose Alencar

    2014-01-01

    Background: Several studies have shown that species of the genus Hyptis, have promising antimicrobial and antifungal effects. Objectives: Identify of chemical constituents of essential oil from leaves of Hyptis martiusii and evaluate its effect against bacterial strains by direct and gaseous contact. Materials and Methods: Essential oil was extracted from leaves of Hyptis martiusii Benth using hydro-distillation, and its composition was determined using gas chromatography–mass spectrometry (GC-MS). Chemical analysis showed that there was a predominance of sesquiterpenes. The leaf essential oil was screened for its minimal inhibitory concentration and modulatory effect of aminoglycoside by the direct (MIC) and gaseous (MID) micro-dilution assays for various pathogenic microorganisms. The essential oil remarkably inhibited the growth of all of the tested bacteria (MIC < 512 ?g/mL) except S. aureus (SA358) multidrug resistant (MRSA) by direct contact. Results: Twenty-four compounds representing 92.13% of the essential oil of leaves were characterized; ? -3-carene (6.88%), 1, 8-cineole (7.01%), trans-caryophyllene (9.21%), Cariophyllene oxide (7.47%) and bicyclogermacrene (10.61%) were found as the major components. Modulatory aminoglycoside effect, by direct contact, was showed antagonistic relationship with antimicrobial activity. The gaseous component of the oil inhibited the bacterial growth of all of the tested bacteria in 50% and 25% of oil concentration and demonstrated synergistic interactions can be attributed to the constituting the oil compounds. Conclusions: These results show that this oil influences the activity of the antibiotic and may be used as an adjuvant in the antibiotic therapy of respiratory tract bacterial pathogens. PMID:25237640

  9. Composite materials: science and engineering

    SciTech Connect

    Chawla, K.K.

    1987-01-01

    The properties and applications of composite materials are examined in an introductory textbook for senior and graduate engineering students. Chapters are devoted to glass, B, C, organic, ceramic, and metallic fibers; polymer, ceramic, and metallic matrix materials; polymer-matrix composites; MMCs; ceramic-matrix composites; CFRPs; and multifilament superconducting composites. Consideration is given to the micromechanics of composites, macromechanical characteristics, strength, fracture, fatigue, and design problems. Diagrams, graphs, photographs, and tables of numerical data are included, and a set of problems is given for each chapter.

  10. Cometary coma chemical composition (C4) mission. [Abstract only

    NASA Technical Reports Server (NTRS)

    Carle, G. C.; Clark, B. C.; Niemann, H. B.; Alexander, M.; Knocke, P. C.; O'Hara, B. J.

    1994-01-01

    Cometary missions are of enormous fundamental importance for many different space science disciplines, including exobiology. Comets are presumed relics of the earliest, most primitive material in the solar nebula and are related to the planetesimals. They undoubtedly provided a general enrichment of volatiles to the inner solar system (contributing to atmospheres and oceans) and may have been key to the origin of life. A Discovery class, comet rendezvous mission, the Cometary Coma Chemical Composition (C4) Mission, was selected for further study by NASA earlier this year. The C4 Mission is a highly focused and usefully-limited subset of the Cometary Rendezvous Asteroid Flyby (CRAF) Mission, concentrating exclusively on measurements which will lead to an understanding of the chemical composition and make-up of the cometary nucleus. The scientific goals of the Cometary Coma Chemical Composition (C4) Mission are to rendezvous with a short-period comet and (1) to determine the elemental, chemical, and isotopic composition of the nucleus and (2) to characterize the chemical and isotopic nature of its atmosphere. Further, it is a goal to obtain preliminary data on the development of the coma (dust and gas composition) as a function of time and orbital position.

  11. Wear of hard materials by hard particles

    SciTech Connect

    Hawk, Jeffrey A.

    2003-10-01

    Hard materials, such as WC-Co, boron carbide, titanium diboride and composite carbide made up of Mo2C and WC, have been tested in abrasion and erosion conditions. These hard materials showed negligible wear in abrasion against SiC particles and erosion using Al2O3 particles. The WC-Co materials have the highest wear rate of these hard materials and a very different material removal mechanism. Wear mechanisms for these materials were different for each material with the overall wear rate controlled by binder composition and content and material grain size.

  12. Composite material heat pipe radiator

    Microsoft Academic Search

    Nelson J. Gernert; David B. Sarraf; Richard J. Guenther

    1996-01-01

    Organic matrix composite material is recognized for its significant strength to weight ratio when compared to metal and consequently was investigated for reducing the mass of heat pipes for future space missions. The particular heat pipe that was constructed and tested was made from an organic matrix composite material applied to a linear of titanium tubing spun to foil thickness

  13. Sitall-base composite materials

    Microsoft Academic Search

    I. I. Beloborodov; A. I. Yuga; N. D. Nazarenko; L. F. Kolesnichenko; N. I. Vlasko

    1976-01-01

    1.The feasibility is demonstrated of producing Sitall-base porous skeletons.2.Impregnation of a porous skeleton with a suspension of PTFE and graphite enables a composite material to be obtained possessing excellent antifriction properties.3.The presence of a metallic filler in such a composite material increases its load-carrying capacity.

  14. Static properties and moisture content properties of polyester fabrics modified by plasma treatment and chemical finishing

    NASA Astrophysics Data System (ADS)

    Kan, C. W.; Yuen, C. W. M.

    2008-01-01

    Low temperature plasma treatment has been conducted in textile industry and has some success in the dyeing and finishing processes. In this paper, an attempt was made to apply low temperature plasma treatment to improve the anti-static property of polyester fabric. The polyester fabrics were treated under different conditions using low temperature plasma. An Orthogonal Array Testing Strategy was employed to determine the optimum treatment condition. After low temperature plasma treatment, the polyester fabrics were evaluated with different characterisation methods. Under the observation of scanning electron microscope, the surface structure of low temperature plasma-treated polyester fabric was seriously altered. This provided more capacity for polyester to capture moisture and hence increase the dissipation of static charges. The relationship between moisture content and half-life decay time for static charges was studied and the results showed that the increment of moisture content would result in shortening the time for the dissipation of static charges. Moreover, there was a great improvement in the anti-static property of the low temperature plasma-treated polyester fabric after comparing with that of the polyester fabric treated with commercial anti-static finishing agent.

  15. Prediction of local ultimate strain and toughness of trabecular bone tissue by Raman material composition analysis.

    PubMed

    Carretta, Roberto; Stüssi, Edgar; Müller, Ralph; Lorenzetti, Silvio

    2015-01-01

    Clinical studies indicate that bone mineral density correlates with fracture risk at the population level but does not correlate with individual fracture risk well. Current research aims to better understand the failure mechanism of bone and to identify key determinants of bone quality, thus improving fracture risk prediction. To get a better understanding of bone strength, it is important to analyze tissue-level properties not influenced by macro- or microarchitectural factors. The aim of this pilot study was to identify whether and to what extent material properties are correlated with mechanical properties at the tissue level. The influence of macro- or microarchitectural factors was excluded by testing individual trabeculae. Previously reported data of mechanical parameters measured in single trabeculae under tension and bending and its compositional properties measured by Raman spectroscopy was evaluated. Linear and multivariate regressions show that bone matrix quality but not quantity was significantly and independently correlated with the tissue-level ultimate strain and postyield work (r = 0.65-0.94). Principal component analysis extracted three independent components explaining 86% of the total variance, representing elastic, yield, and ultimate components according to the included mechanical parameters. Some matrix parameters were both included in the ultimate component, indicating that the variation in ultimate strain and postyield work could be largely explained by Raman-derived compositional parameters. PMID:25695083

  16. Process for preparing a chemical compound enriched in isotope content

    SciTech Connect

    Michaels, E.D.

    1982-08-10

    A process to prepare a chemical enriched in isotope content which includes: (A) a chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; (B) the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; (C) the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; (D) the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products.

  17. Process for preparing a chemical compound enriched in isotope content

    DOEpatents

    Michaels, Edward D. (Spring Valley, OH)

    1982-01-01

    A process to prepare a chemical enriched in isotope content which includes: (a) A chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; (b) the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; (c) the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; (d) the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products.

  18. Vibrational Damping of Composite Materials

    E-print Network

    Biggerstaff, Janet M.

    2006-01-01

    polymeric composites composed of fibers (graphite, Kevlar,by Cape Composites, had intermediate modulus graphite fibersFiber and Resin on the Vibration Damping of Composites Reinforced wit Fiberglass, Graphite, and

  19. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The composite aircraft program component (CAPCOMP) is a graduate level project conducted in parallel with a composite structures program. The composite aircraft program glider (CAPGLIDE) is an undergraduate demonstration project which has as its objectives the design, fabrication, and testing of a foot launched ultralight glider using composite structures. The objective of the computer aided design (COMPAD) portion of the composites project is to provide computer tools for the analysis and design of composite structures. The major thrust of COMPAD is in the finite element area with effort directed at implementing finite element analysis capabilities and developing interactive graphics preprocessing and postprocessing capabilities. The criteria for selecting research projects to be conducted under the innovative and supporting research (INSURE) program are described.

  20. Composite Materials: Sticks and Glue

    NSDL National Science Digital Library

    Stoebe, Thomas G.

    This learning activity will provide a good example of "the effect on strength and stiffness of a material when it is manufactured as a composite." Popsicle sticks will be used to demonstrate the difference between singular materials and composite materials. Students will be able to see the added benefits of using composite materials. This activity would be suitable for elementary school through college level students, with each grade level gaining different educational benefits. The lesson should take from 5 to 20 minutes, depending on grade level. This document will serve as a framework for instructors and may be downloaded in PDF format.

  1. Composite materials: A compilation

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Design, analysis and fabrication techniques for boron-aluminum composite-structure technology is presented and a new method of joining different laminated composites without mechanical fasteners is proposed. Also discussed is a low-cost procedure for rigidifying expanded honeycomb tubing and piping simulations. A brief note on patent information is added.

  2. Hot-wire detector for chemically active materials used in gas chromatography

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Hot-filament detector analyzes chemically active materials used in gas chromatography. The detector reacts chemically with the effluent vapors in the gas chromatographic apparatus to change the electrical resistance of the filament as a function of the affluent composition. Due to the changes produced by chemical action on the filament, the system is often calibrated.

  3. Physicomechanical properties of nickel-base composite materials with dispersed crystallizing glass particles. Part II

    Microsoft Academic Search

    B. L. Rudoi; M. Kh. Shorshorov; G. M. Matveev; B. Ao Borok; R. Po Shchegoleva

    1974-01-01

    1.With rise in the amount of dispersed phase, the hardness of a composite material increases and its ductility decreases, the actual extent of these changes depending upon the chemical composition of the silicate phase.2.Tests have shown that, at 20°C, the short-time strength is a maximum for pure nickel, and falls with increase in dispersed-phase content.3.In the test temperature range 20–400°C,

  4. Composite structural materials. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1980-01-01

    The use of filamentary composite materials in the design and construction of primary aircraft structures is considered with emphasis on efforts to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, and reliability and life prediction. The redesign of a main spar/rib region on the Boeing 727 elevator near its actuator attachment point is discussed. A composite fabrication and test facility is described as well as the use of minicomputers for computer aided design. Other topics covered include (1) advanced structural analysis methids for composites; (2) ultrasonic nondestructive testing of composite structures; (3) optimum combination of hardeners in the cure of epoxy; (4) fatigue in composite materials; (5) resin matrix characterization and properties; (6) postbuckling analysis of curved laminate composite panels; and (7) acoustic emission testing of composite tensile specimens.

  5. Composite materials and method of making

    DOEpatents

    Simmons, Kevin L [Kennewick, WA; Wood, Geoffrey M [North Saanich, CA

    2011-05-17

    A method for forming improved composite materials using a thermosetting polyester urethane hybrid resin, a closed cavity mold having an internal heat transfer mechanism used in this method, and the composite materials formed by this method having a hybrid of a carbon fiber layer and a fiberglass layer.

  6. Clues for biomimetics from natural composite materials

    PubMed Central

    Lapidot, Shaul; Meirovitch, Sigal; Sharon, Sigal; Heyman, Arnon; Kaplan, David L; Shoseyov, Oded

    2013-01-01

    Bio-inspired material systems are derived from different living organisms such as plants, arthropods, mammals and marine organisms. These biomaterial systems from nature are always present in the form of composites, with molecular-scale interactions optimized to direct functional features. With interest in replacing synthetic materials with natural materials due to biocompatibility, sustainability and green chemistry issues, it is important to understand the molecular structure and chemistry of the raw component materials to also learn from their natural engineering, interfaces and interactions leading to durable and highly functional material architectures. This review will focus on applications of biomaterials in single material forms, as well as biomimetic composites inspired by natural organizational features. Examples of different natural composite systems will be described, followed by implementation of the principles underlying their composite organization into artificial bio-inspired systems for materials with new functional features for future medicine. PMID:22994958

  7. Spectral Analysis by XANES Reveals that GPNMB Influences the Chemical Composition of Intact Melanosomes

    SciTech Connect

    T Haraszti; C Trantow; A Hedberg-Buenz; M Grunze; M Anderson

    2011-12-31

    GPNMB is a unique melanosomal protein. Unlike many melanosomal proteins, GPNMB has not been associated with any forms of albinism, and it is unclear whether GPNMB has any direct influence on melanosomes. Here, melanosomes from congenic strains of C57BL/6J mice mutant for Gpnmb are compared to strain-matched controls using standard transmission electron microscopy and synchrotron-based X-ray absorption near-edge structure analysis (XANES). Whereas electron microscopy did not detect any ultrastructural changes in melanosomes lacking functional GPNMB, XANES uncovered multiple spectral phenotypes. These results directly demonstrate that GPNMB influences the chemical composition of melanosomes and more broadly illustrate the potential for using genetic approaches in combination with nano-imaging technologies to study organelle biology.

  8. Novel composite materials synthesized by the high-temperature interaction of pyrrole with layered oxide matrices

    NASA Astrophysics Data System (ADS)

    Pavel, Alexandru Cezar

    The initial goal of the research presented herein was to develop the very first synthetic metal---high-temperature superconductor ceramic composite material, in the specific form of a polypyrrole---Bi2Sr2CaCu 2O8+delta nanocomposite. In the course of scientific investigation, this scope was broadened to encompass structurally and compositionally similar layered bismuthates and simpler layered oxides. The latter substrates were prepared through novel experimental procedures that enhanced the chance of yielding nanostructured morphologies. The designed novel synthesis approaches yielded a harvest of interesting results that may be further developed upon their dissemination in the scientific community. High-temperature interaction of pyrrole with molybdenum trioxide substrates with different crystalline phases and morphologies led to the formation of the first members of a new class of heterogeneous microcomposites characterized by incomplete occupancy by the metal oxide core of the volume encapsulated by the rigid, amorphous permeable polymeric membrane that reproduces the volume of the initial grain of precursor substrate. The method may be applied for various heterogeneous catalyst substrates for the precise determination of the catalytically active crystallographic planes. In a different project, room-temperature, templateless impregnation of molybdenum trioxide substrates with different crystalline phases and morphologies by a large excess of silver (I) cations led to the formation of 1-D nanostructured novel Ag-Mo-O ternary phase in what may be the simplest experimental procedure available to date that has yielded a 1-D nanostructure, regardless the nature of the constituent material. Interaction of this novel ternary phase with pyrrole vapors at high reaction temperatures led to heterogeneous nanostructured composites that exhibited a silver nanorod core. Nanoscrolls of vanadium pentoxide xerogel were synthesized through a novel, facile reflux-based method that employed very acidic pH levels and long reaction times. The nanoscrolls proved to be an excellent precursor for the synthesis of reduced vanadium oxide nanosheets by the redox intercalation of long chain monoamine molecules. In a related development, the very first synthetic metal---mixed-valence polyoxovanadate salt hybrid material was synthesized in the form of a polypyrrole---tetrammonium hexavanadate microcomposite by a redox simultaneous co-precipitation in an aqueous solution. The novel material displayed good mechanical properties towards solid lubricant applications and tunable electronic conductivity. Nanocomposites of polypyrrole---layered bismuthates were produced by the topotactic intercalation of pyrrole and its subsequent in situ polymerization. Insulating and superconducting layered bismuthates were used in a similar experimental procedure that used pre-intercalated iodine species as sacrificial topotactic oxidizing agents. A novel method of iodine intercalation by a solution-based transport procedure was used in the process. Interaction of pyrrole with layered bismuthates at high reaction temperatures led to the formation of polymer-covered metal nanorods as a result of intrinsic lattice templating effect. The successful synthesis of the 1-D heterogeneous nanostructures represents the first example in which nanocomposites were used as precursors. Appropriate doping of the initial layered ceramic substrates led to polymer-covered metal alloy nanorods.

  9. Improved Silica Aerogel Composite Materials

    NASA Technical Reports Server (NTRS)

    Paik, Jong-Ah; Sakamoto, Jeffrey; Jones, Steven

    2008-01-01

    A family of aerogel-matrix composite materials having thermal-stability and mechanical- integrity properties better than those of neat aerogels has been developed. Aerogels are known to be excellent thermal- and acoustic-insulation materials because of their molecular-scale porosity, but heretofore, the use of aerogels has been inhibited by two factors: (1) Their brittleness makes processing and handling difficult. (2) They shrink during production and shrink more when heated to high temperatures during use. The shrinkage and the consequent cracking make it difficult to use them to encapsulate objects in thermal-insulation materials. The underlying concept of aerogel-matrix composites is not new; the novelty of the present family of materials lies in formulations and processes that result in superior properties, which include (1) much less shrinkage during a supercritical-drying process employed in producing a typical aerogel, (2) much less shrinkage during exposure to high temperatures, and (3) as a result of the reduction in shrinkage, much less or even no cracking.

  10. Environmental effects of oilfield chemicals on composite

    SciTech Connect

    Sorem, R.M. [Univ. of Kansas, Lawrence, KS (United States). Dept. of Mechanical Engineering

    1998-12-31

    This paper presents a feasibility study of the effects of oilfield chemicals on composite materials. In this initial study only hydrochloric acid is considered. Initial attempts were made to test stressed specimens, but results were very poor. Subsequent testing was performed to determine how the composite material constituents reacted to the hydrochloric acid. The initial testing was performed on tubular specimens with axial and essentially hoop wound fibers of different materials with different resins. The specimens were loaded in bending to induce representative strains in the tubing. All specimens failed. The second tests consisted of only an environmental soak to determine the amount of mass uptake as well as the reduction in strength. The strength reduction results will be presented at a later time. Testing was performed on S-2 glass, carbon and Kevlar 49 as well as three different resins.

  11. Characterization of nanoporous carbon fibrous materials obtained by chemical activation of plane tree seed under ultrasonic irradiation.

    PubMed

    Kaludjerovi?, Branka V; Jovanovi?, Vladislava M; Stevanovi?, Sanja I; Bogdanov, Žarko D

    2014-03-01

    An ultrasonic irradiation was applied for the impregnation by chemical agents in the chemical activation process of new type of active carbon precursor. Plane tree seed, due to the unique fibrous structure and low cost is a promising eco-friendly raw material for the preparation of activated carbon materials. Ultrasonic irradiation was used for the impregnation step allowing the chemical activation by different agents: potassium or sodium hydroxide, hydrogen peroxide and pyrogallol. The porous structures were examined by nitrogen adsorption/desorption isotherms at 77 K and electrochemically by cyclic voltammetry. The textures of these materials were observed by scanning electron microscopy. The application of ultrasonic irradiation in the impregnation step increased surface area of the final material more than two times in comparison to the material which impregnation in the activation process was by conventional stirring. Ultrasonic irradiation enhances the chemical activation process and the activated carbon fibrous materials with nanoporous structure were obtained by impregnation of seeds with alkaline hydroxides. Total surface areas of these samples were 976 m(2) g(-1) and 1130 m(2) g(-1). These fibers have total specific capacitance as high as 125 F g(-1) and 53 F g(-1) which major fraction in both cases originate from internal micropores structure. PMID:24094648

  12. Composite Materials for Hazard Mitigation of Reactive Metal Hydrides.

    SciTech Connect

    Pratt, Joseph William; Cordaro, Joseph Gabriel; Sartor, George B.; Dedrick, Daniel E.; Reeder, Craig L.

    2012-02-01

    In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested under simulated usage and accident conditions. Mitigating the hazards associated with reactive metal hydrides during an accident while finding a way to keep the original capability of the active material intact during normal use has been the focus of this work. These composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride, in this case a prepared sodium alanate (chosen as a representative reactive metal hydride). It was found that the polymerization of styrene and divinyl benzene could be initiated using AIBN in toluene at 70 degC. The resulting composite materials can be either hard or brittle solids depending on the cross-linking density. Thermal decomposition of these styrene-based composite materials is lower than neat polystyrene indicating that the chemical nature of the polymer is affected by the formation of the composite. The char-forming nature of cross-linked polystyrene is low and therefore, not an ideal polymer for hazard mitigation. To obtain composite materials containing a polymer with higher char-forming potential, siloxane-based monomers were investigated. Four vinyl-containing siloxane oligomers were polymerized with and without added styrene and divinyl benzene. Like the styrene materials, these composite materials exhibited thermal decomposition behavior significantly different than the neat polymers. Specifically, the thermal decomposition temperature was shifted approximately 100 degC lower than the neat polymer signifying a major chemical change to the polymer network. Thermal analysis of the cycled samples was performed on the siloxane-based composite materials. It was found that after 30 cycles the siloxane-containing polymer composite material has similar TGA/DSC-MS traces as the virgin composite material indicating that the polymer is physically intact upon cycling. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride in the form of a composite material reduced the inherent hydrogen storage capacity of the material. This

  13. Chemical composition of Hanford Tank SY-102

    SciTech Connect

    Birnbaum, E.; Agnew, S.; Jarvinen, G.; Yarbro, S.

    1993-12-01

    The US Department of Energy established the Tank Waste Remediation System (TWRS) to safely manage and dispose of the radioactive waste, both current and future, stored in double-shell and single-shell tanks at the Hanford sites. One major program element in TWRS is pretreatment which was established to process the waste prior to disposal using the Hanford Waste Vitrification Plant. In support of this program, Los Alamos National Laboratory has developed a conceptual process flow sheet which will remediate the entire contents of a selected double-shelled underground waste tank, including supernatant and sludge, into forms that allow storage and final disposal in a safe, cost-effective and environmentally sound manner. The specific tank selected for remediation is 241-SY-102 located in the 200 West Area. As part of the flow sheet development effort, the composition of the tank was defined and documented. This database was built by examining the history of liquid waste transfers to the tank and by performing careful analysis of all of the analytical data that have been gathered during the tank`s lifetime. In order to more completely understand the variances in analytical results, material and charge balances were done to help define the chemistry of the various components in the tank. This methodology of defining the tank composition and the final results are documented in this report.

  14. Dual Bioactivities of Essential Oil Extracted from the Leaves of Artemisia argyi as an Antimelanogenic versus Antioxidant Agent and Chemical Composition Analysis by GC/MS

    PubMed Central

    Huang, Huey-Chun; Wang, Hsiao-Fen; Yih, Kuang-Hway; Chang, Long-Zen; Chang, Tsong-Min

    2012-01-01

    The study was aimed at investigating the antimelanogenic and antioxidant properties of essential oil when extracted from the leaves of Artemisia argyi, then analyzing the chemical composition of the essential oil. The inhibitory effect of the essential oil on melanogenesis was evaluated by a mushroom tyrosinase activity assay and B16F10 melanoma cell model. The antioxidant capacity of the essential oil was assayed by spectrophotometric analysis, and the volatile chemical composition of the essential oil was analyzed with gas chromatography-mass spectrometry (GC/MS). The results revealed that the essential oil significantly inhibits mushroom tyrosinase activity (IC50 = 19.16 mg/mL), down-regulates B16F10 intracellular tyrosinase activity and decreases the amount of melanin content in a dose-dependent pattern. Furthermore, the essential oil significantly scavenged 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2?-azino-bis (3-ethylbenzthiazoline- 6-sulphonic acid) ABTS radicals, showed an apparent reduction power as compared with metal-ion chelating activities. The chemicals constituents in the essential oil are ether (23.66%), alcohols (16.72%), sesquiterpenes (15.21%), esters (11.78%), monoterpenes (11.63%), ketones (6.09%), aromatic compounds (5.01%), and account for a 90.10% analysis of its chemical composition. It is predicted that eucalyptol and the other constituents, except for alcohols, in the essential oil may contribute to its antioxidant activities. The results indicated that essential oil extracted from A. argyi leaves decreased melanin production in B16F10 cells and showed potent antioxidant activity. The essential oil can thereby be applied as an inhibitor of melanogenesis and could also act as a natural antioxidant in skin care products. PMID:23203088

  15. Chemical Composition of Mycelium of the Thermotolerant Fungus Penicillium atrovenetum

    Microsoft Academic Search

    Zh. Tashpulatov; B. G. Baibaev; T. S. Shul'man

    2000-01-01

    The chemical composition of mycelium ofPenicillium atrovenetum,a highly active producer of cellulase and protein, is studied. The protein content in the mycelium is 37.6%. The highest amino-acid content occurs in the albumin fraction (18.28%)

  16. Degradation of simazine from aqueous solutions by diatomite-supported nanosized zero-valent iron composite materials.

    PubMed

    Sun, Zhiming; Zheng, Shuilin; Ayoko, Godwin A; Frost, Ray L; Xi, Yunfei

    2013-12-15

    A novel composite material based on deposition of nanosized zero-valent iron (nZVI) particles on acid-leached diatomite was synthesised for the removal of a chlorinated contaminant in water. The nZVI/diatomite composites were characterised by X-ray diffraction, scanning electron microscopy, elemental analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. Compared with the pure nZVI particles, better dispersion of nZVI particles on the surface or inside the pores of diatom shells was observed. The herbicide simazine was selected as the model chlorinated contaminant and the removal efficiency by nZVI/diatomite composite was compared with that of the pristine nZVI and commercial iron powder. It was found that the diatomite supported nZVI composite material prepared by centrifugation exhibits relatively better efficient activity in decomposition of simazine than commercial Fe, lab synthesised nZVI and composite material prepared via rotary evaporation, and the optimum experimental conditions were obtained based on a series of batch experiments. This study on immobilising nZVI particles onto diatomite opens a new avenue for the practical application of nZVI and the diatomite-supported nanosized zero-valent iron composite materials have potential applications in environmental remediation. PMID:24231330

  17. The Effect of Liquid Smoking of Anchovy (Engraulis encrasicolus, L. 1758) Fillets on Sensory, Meat Yield, Polycyclic Aromatic Hydrocarbon (PAH) Content, and Chemical Changes

    Microsoft Academic Search

    Zayde Alçiçek; Özge Zencir; Gül Çelik Çakiro?ullari; Hasan Hüseyin Atar

    2010-01-01

    In this study, the effects of a commercial liquid smoke flavoring agent and two different brining solutions applied on fillets of anchovy were investigated by performing sensory analyses, meat yield, polycyclic aromatic hydrocarbon (PAH) content, and chemical composition analyses. Fillets were brined at 40 and 65% for 4 h at 4°C. Meat yield, sensorial acceptability, and chemical compositions were affected

  18. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 false Spirits content of chemicals produced. 19.308 Section 19.308...Production of Distilled Spirits Rules for Chemical Byproducts § 19.308 Spirits content of chemicals produced. All chemicals and...

  19. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 false Spirits content of chemicals produced. 19.308 Section 19.308...Production of Distilled Spirits Rules for Chemical Byproducts § 19.308 Spirits content of chemicals produced. All chemicals and...

  20. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 false Spirits content of chemicals produced. 19.308 Section 19.308...Production of Distilled Spirits Rules for Chemical Byproducts § 19.308 Spirits content of chemicals produced. All chemicals and...

  1. Cadmium Chemical Form in Mine Waste Materials by X-ray Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Diacomanolis, V.; Ng, J. C.; Sadler, R.; Harris, H. H.; Nomura, M.; Noller, B. N.

    2010-06-01

    This study examines the molecular form of cadmium (Cd) present in mine wastes by X-ray Absorption Spectroscopy (XAS; Cd>20 mg/kg) using the K-edge of Cd at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Mine waste materials and zinc concentrate were analyzed for Cd by ICPMS prior to undertaking XAS (range 21-452 mg/kg). Model compounds (CdO, Cd(OH)2, CdCO3, Cdacetate, CdS, Cdstearate, CdDEDTC) and samples were examined in solid form at 20 K. The XANES spectra showed similar E max values for both model compounds and samples. The EXAFS showed that Cd-S in CdS, gives a flatter spectrum in the extended region compared to Cd-O found with CdCO3, CdO and Cd Stearate. Linear combination fitting with model Cd compounds did not give clear assignments of composition, indicating that more detailed EXAFS spectra is required as mineral forms containing Cd were present rather than simple Cd compounds such as CdCO3. The Cd bond for a single shell model in mine waste sample matrices appears to be either Cd-O or Cd-S, or a combination of both. Comparison of molecular data from the XAS studies with bioaccessibility data giving a prediction of bioavailability for mine waste materials provides useful information about the significance of the cadmium form as a contaminant for health risk assessment purposes.

  2. Cadmium Chemical Form in Mine Waste Materials by X-ray Absorption Spectroscopy

    SciTech Connect

    Diacomanolis, V.; Ng, J. C. [University of Queensland, National Research Centre for Environmental Toxicology, Coopers Plains, QLD, 4008 (Australia); Sadler, R. [School of Public Health, Griffith University, Brisbane, QLD (Australia); Harris, H. H. [School of Chemistry and Physics, University of Adelaide, Adelaide, SA (Australia); Nomura, M. [Photon Factory, Institute of Material Structure Science, Tsukuba (Japan); Noller, B. N. [University of Queensland, Centre For Mined Land Rehabilitation, St Lucia 4072 QLD (Australia)

    2010-06-23

    This study examines the molecular form of cadmium (Cd) present in mine wastes by X-ray Absorption Spectroscopy (XAS; Cd>20 mg/kg) using the K-edge of Cd at the Photon Factory Advanced Ring (PF-AR), NW10A beam line at KEK-Tsukuba-Japan. Mine waste materials and zinc concentrate were analyzed for Cd by ICPMS prior to undertaking XAS (range 21-452 mg/kg). Model compounds (CdO, Cd(OH){sub 2}, CdCO{sub 3}, Cdacetate, CdS, Cdstearate, CdDEDTC) and samples were examined in solid form at 20 K. The XANES spectra showed similar E max values for both model compounds and samples. The EXAFS showed that Cd-S in CdS, gives a flatter spectrum in the extended region compared to Cd-O found with CdCO{sub 3}, CdO and Cd Stearate. Linear combination fitting with model Cd compounds did not give clear assignments of composition, indicating that more detailed EXAFS spectra is required as mineral forms containing Cd were present rather than simple Cd compounds such as CdCO{sub 3}. The Cd bond for a single shell model in mine waste sample matrices appears to be either Cd-O or Cd-S, or a combination of both. Comparison of molecular data from the XAS studies with bioaccessibility data giving a prediction of bioavailability for mine waste materials provides useful information about the significance of the cadmium form as a contaminant for health risk assessment purposes.

  3. The influence of the chemical composition of cell culture material on the growth and antibody production of hybridoma cells.

    PubMed

    Heilmann, K; Groth, Th; Behrsing, O; Albrecht, W; Schossig, M; Lendlein, A; Micheel, B

    2005-02-01

    The multiplication and antibody production of murine hybridoma cells cultured on five different polymer membranes were tested and compared with conventional tissue culture polystyrene (TCPS). Membranes were prepared from polyacrylonitrile (PAN) and acrylonitrile copolymerized with N-vinylpyrrolidone (NVP20, NVP30), Na-methallylsulfonate (NaMAS) and N-(3-amino-propyl-methacrylamide-hydrochloride) (APMA). Cell number and antibody concentration were quantified as criteria for viability and productivity. Adhesion of hybridoma cells was characterized by vital and scanning electron microscopy. The results suggest that a strong adhesion of cells, observed on APMA and TCPS, increased cell growth but reduced monoclonal antibody production. In contrast membranes with lowered adhesivity such as NVP20 provided favourable conditions for monoclonal antibody production. In addition it was shown that this membrane also possessed a minor fouling as indicated by the low decrease of water flux across the membrane after protein adsorption. It was concluded that NVP20 could be a suitable material for the development of hollow fibre membranes for bioreactors. PMID:15639091

  4. Piezoelectric Nanoparticle-Polymer Composite Materials

    NASA Astrophysics Data System (ADS)

    McCall, William Ray

    Herein we demonstrate that efficient piezoelectric nanoparticle-polymer composite materials can be synthesized and fabricated into complex microstructures using sugar-templating methods or optical printing techniques. Stretchable foams with excellent tunable piezoelectric properties are created by incorporating sugar grains directly into polydimethylsiloxane (PDMS) mixtures containing barium titanate (BaTiO3 -- BTO) nanoparticles and carbon nanotubes (CNTs), followed by removal of the sugar after polymer curing. Porosities and elasticity are tuned by simply adjusting the sugar/polymer mass ratio and the electrical performance of the foams showed a direct relationship between porosity and the piezoelectric outputs. User defined 2D and 3D optically printed piezoelectric microstructures are also fabricated by incorporating BTO nanoparticles into photoliable polymer solutions such as polyethylene glycol diacrylate (PEGDA) and exposing to digital optical masks that can be dynamically altered. Mechanical-to-electrical conversion efficiency of the optically printed composite is enhanced by chemically altering the surface of the BTO nanoparticles with acrylate groups which form direct covalent linkages with the polymer matrix under light exposure. Both of these novel materials should find exciting uses in a variety of applications including energy scavenging platforms, nano- and microelectromechanical systems (NEMS/MEMS), sensors, and acoustic actuators.

  5. Young upper crustal chemical composition of the orogenic Japan Arc

    NASA Astrophysics Data System (ADS)

    Togashi, Shigeko; Imai, Noboru; Okuyama-Kusunose, Yasuko; Tanaka, Tsuyoshi; Okai, Takashi; Koma, Takeshi; Murata, Yasuaki

    2000-11-01

    A new geochemical estimate of the young (mainly Paleozoic age to present) upper crust of the Japan Arc shows a dacitic composition in contrast to the idea that andesite is predominant in active orogenic arcs. Temporal changes in composition are not significant from the Paleozoic age to the present for the Japan Arc. The major element composition is similar to previous models of old cratonic upper crusts. The coincidence in the major elements between young and old crusts indicates that essential mechanisms during crust formation have not changed from the Archean era to the present. In trace element compositions the average young upper crust of the Japan Arc has higher Sb and As concentrations and lower concentrations of alkaline, light rare earth, and high field strength elements with respect to previous models of continental upper crusts. The large degree of constancy of trace element composition in marine sedimentary rocks is in contrast to the large variety in igneous rocks. However, the averages for both accretionary and nonaccretionary sedimentary rocks are almost identical to the average for the igneous rocks of the Japan Arc, with the exceptions of high Sb and As concentrations in unmetamorphosed sedimentary rocks. The compositional homogeneity among different types of rocks on an arc scale implies that recycling processes mechanically mix the arc-derived igneous materials to homogenize the chemical composition during erosion, transportation, sedimentation, accretion, and uplifting. Since the contribution of oceanic crust to the composition of arc crust is small, the recycling processes have not changed the bulk upper crustal composition of the active continental margin except increase the Sb and As from sediments. Instead, the influx of differentiated acidic rocks from depth is essential to characterize the orogenic crust formation of the young Japan Arc. The characteristically low incompatible element content of the Japanese upper arc crust appears inherited from parental magmas derived from a mantle source depleted during a long-term evolution.

  6. Composite structural materials. [aircraft applications

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The development of composite materials for aircraft applications is addressed with specific consideration of physical properties, structural concepts and analysis, manufacturing, reliability, and life prediction. The design and flight testing of composite ultralight gliders is documented. Advances in computer aided design and methods for nondestructive testing are also discussed.

  7. Extraction of the volatile oil from Carum carvi of Tunisia and Lithuania by supercritical carbon dioxide: chemical composition and antiulcerogenic activity.

    PubMed

    Baananou, Sameh; Bagdonaite, Edita; Marongiu, Bruno; Piras, Alessandra; Porcedda, Silvia; Falconieri, Danilo; Boughattas, Naceur

    2013-01-01

    This study investigates whether the essential oil prepared from Carum carvi seeds exhibits antiulcerogenic activity. Its volatile oil was obtained by supercritical fluid extraction (SFE) and by hydrodistillation. The essential oils were analysed by GC-MS to monitor their composition. The chemical analysis revealed that the essential oils extracted under SFE conditions had high carvone and limonene contents. The antiulcerogenic activity was evaluated by the HCl/ethanol method, which causes injury to the gastric mucosa. Three treated groups received the essential oil (100-300 mg/kg). The reference group received omeprazole (30 mg/kg) and the control group received NaCl. After 30 min, all groups were treated with HCl/EtOH for gastric ulcer induction. The results show C. carvi essential oil enhanced a significant inhibition of 47%, 81% and 88%, respectively, for three doses of essential oil used, which was similar to that induced by omeprazole (95%) (p < 0.005). PMID:23495832

  8. Chemical and Physical Modification of Graphitic Materials by Oxidative Processes and Solvent Intercalation 

    E-print Network

    Werke, Carrie Beth

    2014-08-27

    is by chemical functionalization, such as oxidation. This work looks at two different oxidation techniques for graphite; UV/O3 exposure and biased AFM lithography for broad and local oxidation, respectively. For the supported graphitic samples including graphene...

  9. Carbon Materials for Chemical Capacitive Energy Storage

    SciTech Connect

    Zhai, Yunpu [Fudan Univ., Shanghai (China). Lab. of Advanced Materials; Dou, Yuqian [Northeastern Univ., Shenyang (China); Zhao, Dongyuan [Fudan Univ., Shanghai (China). Lab. of Advanced Materials; Fulvio, Pasquale F. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Mayes, Richard T. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Dai, Sheng [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

    2011-11-09

    Carbon materials have attracted intense interests as electrode materials for electrochemical capacitors, because of their high surface area, electrical conductivity, chemical stability and low cost. Activated carbons produced by different activation processes from various precursors are the most widely used electrodes. Recently, with the rapid growth of nanotechnology, nanostructured electrode materials, such as carbon nanotubes and template-synthesized porous carbons have been developed. Their unique electrical properties and well controlled pore sizes and structures facilitate fast ion and electron transportation. In order to further improve the power and energy densities of the capacitors, carbon-based composites combining electrical double layer capacitors (EDLC)-capacitance and pseudo-capacitance have been explored. They show not only enhanced capacitance, but as well good cyclability. In this review, recent progresses on carbon-based electrode materials are summarized, including activated carbons, carbon nanotubes, and template-synthesized porous carbons, in particular mesoporous carbons. Their advantages and disadvantages as electrochemical capacitors are discussed. At the end of this review, the future trends of electrochemical capacitors with high energy and power are proposed.

  10. Carbon materials for chemical capacitive energy storage.

    PubMed

    Zhai, Yunpu; Dou, Yuqian; Zhao, Dongyuan; Fulvio, Pasquale F; Mayes, Richard T; Dai, Sheng

    2011-11-01

    Carbon materials have attracted intense interests as electrode materials for electrochemical capacitors, because of their high surface area, electrical conductivity, chemical stability and low cost. Activated carbons produced by different activation processes from various precursors are the most widely used electrodes. Recently, with the rapid growth of nanotechnology, nanostructured electrode materials, such as carbon nanotubes and template-synthesized porous carbons have been developed. Their unique electrical properties and well controlled pore sizes and structures facilitate fast ion and electron transportation. In order to further improve the power and energy densities of the capacitors, carbon-based composites combining electrical double layer capacitors (EDLC)-capacitance and pseudo-capacitance have been explored. They show not only enhanced capacitance, but as well good cyclability. In this review, recent progresses on carbon-based electrode materials are summarized, including activated carbons, carbon nanotubes, and template-synthesized porous carbons, in particular mesoporous carbons. Their advantages and disadvantages as electrochemical capacitors are discussed. At the end of this review, the future trends of electrochemical capacitors with high energy and power are proposed. PMID:21953940

  11. Recycling of composite materials

    Microsoft Academic Search

    M. Buggy; L. Farragher; W. Madden

    1995-01-01

    An economic survey of composite manufacturing was carried out to help to identify suitable fibre\\/resin systems for recycling trials. Three separate recycling strategies were also adopted. The first of these was the re-use of in-process polyester\\/glass prepreg offcuts, which were quantified and then reprocessed using a simple pressing technique. Three different panel types were pressed and subjected to comparative physical

  12. Biosorption of copper by marine algae Gelidium and algal composite material in a packed bed column.

    PubMed

    Vilar, Vítor J P; Botelho, Cidália M S; Loureiro, José M; Boaventura, Rui A R

    2008-09-01

    Marine algae Gelidium and algal composite material were investigated for the continuous removal of Cu(II) from aqueous solution in a packed bed column. The biosorption behaviour was studied during one sorption-desorption cycle of Cu(II) in the flow through column fed with 50 and 25 mg l(-1) of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of approximately 13 and 3 mg g(-1), respectively, for algae Gelidium and composite material. The breakthrough time decreases as the inlet copper concentration increases, for the same flow rate. The pH of the effluent decreases over the breakthrough time of copper ions, which indicates that ion exchange is one of the mechanisms involved in the biosorption process. Temperature has little influence on the metal uptake capacity and the increase of the ionic strength reduces the sorption capacity, decreasing the breakthrough time. Desorption using 0.1M HNO(3) solution was 100% effective. After two consecutive sorption-desorption cycles no changes in the uptake capacity of the composite material were observed. A mass transfer model including film and intraparticle resistances, and the equilibrium relationship, for adsorption and desorption, was successfully applied for the simulation of the biosorption column performance. PMID:18053711

  13. The chemical composition of Polaris

    NASA Astrophysics Data System (ADS)

    Luck, R. E.; Bond, H. E.

    1986-04-01

    From high signal-to-noise coude Reticon spectral obtained at Lick Observatory, the chemical composition of the bright Population I Cepheid Polaris (Alpha UMi) has been determined. The chemical abundances in Polaris are found to be completely typical of normal F-G supergiants. The iron abundance is solar (Fe/H = 0.0), and other metals are present in essentially solar ratios. Carbon is deficient (C/H = -0.4) and nitrogen overabundant (N/H = +0.4) relative to solar abundances, indicating the presence of CN-cycle products at the surface. Oxygen shows an underabundance (O/H = -0.2) that is also typical of F-G supergiants, but is not as easily understood.

  14. Impact of seed layer on material quality of epitaxial germanium on silicon deposited by low pressure chemical vapor deposition

    Microsoft Academic Search

    Oluwamuyiwa O. Olubuyide; David T. Danielson; Lionel C. Kimerling; Judy L. Hoyt

    2006-01-01

    The impact of the growth conditions of the germanium seed layer on the material quality of epitaxial germanium grown on (100) silicon by Low Pressure Chemical Vapor Deposition is studied. In order to obtain a smooth surface morphology, a thin Ge seed layer is grown at low temperature, followed by a thick Ge cap layer at high temperature. An optimal

  15. In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

    DOEpatents

    Kim, Choong Paul; Hays, Charles C.; Johnson, William L.

    2004-03-23

    A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.

  16. In-situ ductile metal/bulk metallic glass matrix composites formed by chemical partitioning

    DOEpatents

    Kim, Choong Paul (Northridge, CA); Hays, Charles C. (Pasadena, CA); Johnson, William L. (Pasadena, CA)

    2007-07-17

    A composite metal object comprises ductile crystalline metal particles in an amorphous metal matrix. An alloy is heated above its liquidus temperature. Upon cooling from the high temperature melt, the alloy chemically partitions, forming dendrites in the melt. Upon cooling the remaining liquid below the glass transition temperature it freezes to the amorphous state, producing a two-phase microstructure containing crystalline particles in an amorphous metal matrix. The ductile metal particles have a size in the range of from 0.1 to 15 micrometers and spacing in the range of from 0.1 to 20 micrometers. Preferably, the particle size is in the range of from 0.5 to 8 micrometers and spacing is in the range of from 1 to 10 micrometers. The volume proportion of particles is in the range of from 5 to 50% and preferably 15 to 35%. Differential cooling can produce oriented dendrites of ductile metal phase in an amorphous matrix. Examples are given in the Zr--Ti--Cu--Ni--Be alloy bulk glass forming system with added niobium.

  17. Investigation of lamp chemical composition by laser-induced breakdown spectroscopy

    SciTech Connect

    Chen, N.H.; Adler, H.G.; Lapatovich, W.P. [Osram Sylvania, Beverly, MA (United States)

    1998-12-31

    The utilization of laser-induced breakdown spectroscopy (LIBS) as a non-destructive experimental diagnostic for studying lighting devices is discussed. LIBS involves the creation of a small plasma localized at the focus of a pulsed laser beam, and corresponding analysis of the spectrally dispersed radiation from the plasma. LIBS has been used as a method for determining the minority elemental composition of various types of samples. This work is aimed at applying LIBS to the species of interest found in metal halide discharge lamps. A 532 nm, 3 ns FWHM pulse from a Nd:YAG laser was used to produce a localized plasma in the interior of a vitreous silica tube containing mercury and sodium-scandium iodides, while the tube was maintained at operating temperatures in an oven. Spectral features corresponding to Hg, Na, and Sc atomic emission were observed, originating from the evaporated fill chemicals. Time-resolved spectroscopy was used to record emission spectra at delay times on the order of a few microseconds following the laser pulse. At appropriate delay times, the atomic emission lines could be separated from the continuum background. Effective (spatially averaged) plasma temperatures vs. delay time were determined from Boltzmann plots of atomic Sc emission lines. The use of integrated line intensities as an indication of species concentration will be discussed.

  18. Evaluation of body composition and nitrogen content of renal patients on chronic dialysis as determined by total body neutron activation

    SciTech Connect

    Cohn, S.H.; Brennan, B.L.; Yasumura, S.; Vartsky, D.; Vaswani, A.N.; Ellis, K.J.

    1983-07-01

    Total body protein (nitrogen), body cell mass (potassium), fat, and water were measured in 15 renal patients on maintenance hemodialysis (MHD). Total body nitrogen was measured by means of prompt ..gamma.. neutron activation analysis; total body water was determined with tritium labeled water; total body potassium was measured by whole body counting. The extracellular water was determined by a technique utilizing the measurement of total body chloride and plasma chloride. When compared with corresponding values of a control group of the same age, sex, and height, the protein content, body cell mass, and total body fat of the MHD patients were within the normal range. The only significant change was an increase in the extracellular water/body cell mass ratio in the male MHD patients compared to the control. The lack of significant difference of the nitrogen values of the MHD patients compared to matched controls suggests that dialysis minimizes any residual effects of uremic toxicity or protein-calorie malnutrition. These findings further suggest that there is a need to reevaluate the traditional anthropometric and biochemical standards of nutritional status for MHD patients. It was concluded that it is particularly important to measure protein stores of MHD patients with low protein intake to ascertain nutritional status. Finally, in vivo measurement of total body nitrogen and potassium for determination of body composition provides a simple, direct, and accurate assessment of the nutritional status of MHD patients.

  19. Structural health monitoring of smart composite materials by using EFPI and FBG sensors

    Microsoft Academic Search

    Jinsong Leng; Anand Asundi

    2003-01-01

    Structural health monitoring (SHM) including the real-time cure monitoring and non-destructive evaluation (NDE) in-service is very important and definitely demanded for safely working of high performance composite structures in situ. It is very difficult to carry out by using conventional methods. A unique opportunity was provided to real-time monitor the health status of composite structures by using embedded fiber optic

  20. Machining of Sitall-base composite materials

    Microsoft Academic Search

    L. F. Kolesnichenko; N. D. Nazarenko; A. I. Yuga; N. I. Vlasko; F. D. Ivashov; L. L. Sukhikh; G. A. Sedlyar

    1976-01-01

    Investigations have shown that in the grinding of Sitall with an abrasive tool removal of material is slow owing to poor heat transfer from the cutting zone and the high hardness of Sitall. By contrast, use of diamond disks in the grinding of Sitall-base composite materials enables high rates of material removal to be attained with a good surface finish.

  1. Nanophase and Composite Optical Materials

    NASA Technical Reports Server (NTRS)

    2003-01-01

    This talk will focus on accomplishments, current developments, and future directions of our work on composite optical materials for microgravity science and space exploration. This research spans the order parameter from quasi-fractal structures such as sol-gels and other aggregated or porous media, to statistically random cluster media such as metal colloids, to highly ordered materials such as layered media and photonic bandgap materials. The common focus is on flexible materials that can be used to produce composite or artificial materials with superior optical properties that could not be achieved with homogeneous materials. Applications of this work to NASA exploration goals such as terraforming, biosensors, solar sails, solar cells, and vehicle health monitoring, will be discussed.

  2. [Comparison of the chemical composition between fresh and dried venenum bufonis by UPLC-Orbitrap MS].

    PubMed

    He, Jing; Li, Yan; Si, Nan; Zhao, Hai-Yu; Bian, Bao-Lin; Wang, Hong-Jie

    2014-10-01

    To identify the active components in Bufo melanostictus Schneider and clarify the difference between fresh and dried Venenum Bufonis, a UPLC-Orbitrap MS method has been established. The separation was performed with gradient elution of acetonitrile and water (with 0.1% formic acid) as mobile phase. By comparing their retention time and high resolution mass data of Venenum Bufonis extracts, 39 effective components were primarily identified by MS/MS analysis in positive ion mode. Twenty-six of them were bufadienolides. There were significant differences in the main composition between fresh and dried Venenum Bufonis. There are fewer bufadienolides in fresh toad venom. PMID:25577877

  3. High-temperature composite materials

    Microsoft Academic Search

    Yu. L. Pilipovskii; L. G. Vishnevskii; T. V. Grudina; L. N. Pereselentseva

    1996-01-01

    In the second half of the 60's the development of composite materials extremely necessary in service under conditions of intense short-term action of high-temperature gas flows which bear a significant quantity of condensed phase was started in the Institute of Material Science under the leadership of I. N. Frantsevich and then D. M. Karpinos. These materials must possess high erosion-

  4. Oxygen and Magnesium Isotopic Compositions of Asteroidal Materials Returned from Itokawa by the Hayabusa Mission

    NASA Technical Reports Server (NTRS)

    Yurimoto, H; Abe, M.; Ebihara, M.; Fujimura, A.; Hashizume, K.; Ireland, T. R.; Itoh, S.; Kawaguchi, K.; Kitajima, F.; Mukai, T.; Nagao, K.; Nakamura, T.; Naraoka, H.; Noguchi, T.; Okazaki, R.; Sakamoto, N.; Seto, Y.; Tsuchiyama, A.; Uesugi, M.; Yada, T.; Yoshikawa, M.; Zolensky, M.

    2011-01-01

    The Hayabusa spacecraft made two touchdowns on the surface of Asteroid 25143 Itokawa on November 20th and 26th, 2005. The Asteroid 25143 Itokawa is classified as an S-type asteroid and inferred to consist of materials similar to ordinary chondrites or primitive achondrites [1]. Near-infrared spectroscopy by the Hayabusa spacecraft proposed that the surface of this body has an olivine-rich mineral assemblage potentially similar to that of LL5 or LL6 chondrites with different degrees of space weathering [2]. The spacecraft made the reentry into the Earth s atmosphere on June 12th, 2010 and the sample capsule was successfully recovered in Australia on June 13th, 2010. Although the sample collection processes on the Itokawa surface had not been made by the designed operations, more than 1,500 grains were identified as rocky particles in the sample curation facility of JAXA, and most of them were judged to be of extraterrestrial origin, and definitely from Asteroid Itokawa on November 17th, 2010 [3]. Although their sizes are mostly less than 10 microns, some larger grains of about 100 microns or larger were also included. The mineral assembly is olivine, pyroxene, plagioclase, iron sulfide and iron metal. The mean mineral compositions are consistent with the results of near-infrared spectroscopy from Hayabusa spacecraft [2], but the variations suggest that the petrologic type may be smaller than the spectroscopic results. Several tens of grains of relatively large sizes among the 1,500 grains will be selected by the Hayabusa sample curation team for preliminary examination [4]. Each grain will be subjected to one set of preliminary examinations, i.e., micro-tomography, XRD, XRF, TEM, SEM, EPMA and SIMS in this sequence. The preliminary examination will start from the last week of January 2011. Therefore, samples for isotope analyses in this study will start from the last week of February 2011. By the time of the LPSC meeting we will have measured the oxygen and magnesium isotopic composition of several grains. We will present the first results from the isotope analyses that will have been performed.

  5. Fatigue Crack and Porosity Measurement in Composite Materials by Thermographic and Ultrasonic Methods

    NASA Technical Reports Server (NTRS)

    Walker, James L.; Russell, Samuel S.; Suits, Michael W.; Workman, Gary L.; Watson, Jason M.; Thom, Robert (Technical Monitor)

    2002-01-01

    Many nondestructive methods exist for the detection of localized material anomalies in an otherwise good composite structure. The problem arises when the material system as a whole has degraded during service or was improperly manufactured. Porosity and intra-ply microcracking are two such conditions that in unlined composite pressure vessels can be very troublesome to detect and when linked through the thickness can be critical to mission success. These leak paths may lead to loss of pressure/propellant, increased risk of explosion and possible cryo-pumping. Research sought nondestructive methods for quantifying porosity and microcracking in composite tankage. Both thermographic and resonance ultrasound methods have been utilized with artificial neural network and statistical approaches to analyze the data. Resonant ultrasound spectroscopy provides measurements, which are sensitive to fine details in the materials character, such as micro-cracking and porosity. Here, the higher frequency (shorter wavelength) components of the signal train provide more significant interaction with the defects causing the spectral characteristics to shift toward lower amplitudes at the higher frequencies. As the density of the defects increases more interactions occur and more drastic amplitude changes are observed. From a thermal perspective, the higher the defect density the lower the through thickness thermal diffusivity will be. Utilizing a point heat source, and thermographically recording the heat profile with time, diffusivity calculations can be made which in turn can be related to the relative quality of the material. Preliminary experiments to verify the measurable effect on the resonance spectrum of the ultrasonic data to detect microcracking and for porosity detection thermographically are presented. Methods involving supervised and unsupervised artificial neural networks as well as other clustering algorithms are developed for signal identification.

  6. Commercial riboflavin production by recombinant Bacillus subtilis : down-stream processing and comparison of the composition of riboflavin produced by fermentation or chemical synthesis

    Microsoft Academic Search

    W Bretzel; W Schurter; B Ludwig; E Kupfer; S Doswald; M Pfister; A P G M van Loon

    1999-01-01

      A novel process for riboflavin production using a recombinant Bacillus subtilis strain has been developed. Here we describe a down-stream processing procedure to obtain riboflavin qualities having a minimal\\u000a content of 96% (‘feed-grade’) and 98% (‘food\\/pharma-grade’) riboflavin, respectively. Compared to riboflavin produced by chemical\\u000a synthesis, products with improved chemical purity were obtained. All compounds representing more than 0.1% of the

  7. Chemical composition and physical quality characteristics of Ghanaian cocoa beans as affected by pulp pre-conditioning and fermentation

    Microsoft Academic Search

    Emmanuel Ohene Afoakwa; Jennifer Quao; Jemmy Takrama; Agnes Simpson Budu; Firibu Kwesi Saalia

    Investigations were conducted to evaluate the effects of pod storage (as a means of pulp preconditioning) and fermentation\\u000a on the chemical composition and physical characteristics of Ghanaian cocoa beans. A 4?×?2 full factorial design with factors\\u000a as pod storage (0, 7, 14, 21 days) and cocoa treatment (fermented and unfermented) were conducted. Samples were analyzed for\\u000a their chemical composition (moisture, crude

  8. Composite materials for space applications

    NASA Technical Reports Server (NTRS)

    Rawal, Suraj P.; Misra, Mohan S.; Wendt, Robert G.

    1990-01-01

    The objectives of the program were to: generate mechanical, thermal, and physical property test data for as-fabricated advanced materials; design and fabricate an accelerated thermal cycling chamber; and determine the effect of thermal cycling on thermomechanical properties and dimensional stability of composites. In the current program, extensive mechanical and thermophysical property tests of various organic matrix, metal matrix, glass matrix, and carbon-carbon composites were conducted, and a reliable database was constructed for spacecraft material selection. Material property results for the majority of the as-fabricated composites were consistent with the predicted values, providing a measure of consolidation integrity attained during fabrication. To determine the effect of thermal cycling on mechanical properties, microcracking, and thermal expansion behavior, approximately 500 composite specimens were exposed to 10,000 cycles between -150 and +150 F. These specimens were placed in a large (18 cu ft work space) thermal cycling chamber that was specially designed and fabricated to simulate one year low earth orbital (LEO) thermal cycling in 20 days. With this rate of thermal cycling, this is the largest thermal cycling unit in the country. Material property measurements of the thermal cycled organic matrix composite laminate specimens exhibited less than 24 percent decrease in strength, whereas, the remaining materials exhibited less than 8 percent decrease in strength. The thermal expansion response of each of the thermal cycled specimens revealed significant reduction in hysteresis and residual strain, and the average CTE values were close to the predicted values.

  9. [Estimation of leaf area index by normalized composite vegetation index fusing the spectral feature of canopy water content].

    PubMed

    Cao, Shi; Liu, Xiang-Nan; Liu, Mei-Ling; Cao, Shan; Yao, Shuai

    2011-02-01

    The accurate inversion of leaf area index (LADI) in canopy is very important for guiding crop management and assessing crop yield. Sixty samples belonging to corn in four different areas of Jilin City were scanned by ASD field pro3 and LAI-2000 for optical data and LAI. A new vegetation index, the normalized composite Vegetation index (NCVI), containing the factor of canopy water content, is proposed in the present paper for a better quantitative estimation of LAI than with the remotely sensed normalized difference vegetation index (NDVI), especially in the arid and semi-arid areas. A model was built for inversion of LAI with NCVI, and experience validation. The results showed that there was a good linear correlation between the simulation LAI inversed from NCVI model and the real LAI values. The model breaking the limitations of the traditional empirical models for LAI inversion has a good result for estimating LAI of the dense canopy whose LAI value was greater than 3. In addition, NCVI model was very sensitive to the water environment of soil, and the inversion result in the arid and semi-arid areas was superior to the general area. PMID:21510408

  10. Manufacture of nickel base composite materials with dispersed glass particles by the powder metallurgy method. Part I

    Microsoft Academic Search

    B. L. Rudoi; M. Kh. Shorshorov; G. M. Matveev; B. A. Borok; R. P. Shchegoleva

    1974-01-01

    1.A technique has been developed for the manufacture of rods of nickel base composite materials containing crystallizing glass particles. Such rods are characterized by a uniform distribution of dispersed phase particles throughout the metal and have densities close to theoretical.2.A study was made of the specific load in the extrustion of sintered compacts as a function of the amount and

  11. Incoherent imaging of materials structure and composition by Z-contrast stem

    SciTech Connect

    Pennycook, S.J.; Jesson, D.E.; Chisholm, M.F.

    1990-05-01

    It is shown how the use of a high angle annular detector in a STEM provides images which show strong compositional sensitivity and almost perfect incoherent characteristics. No contrast reversals occur with defocus or sample thickness and the contribution of an atomic string is insensitive to the distribution and strength of neighboring strings. The image is best described in real space as a simple convolution of the incident probe intensity profile with an object function sharply peaked at the atomic strings having a strength dependent on composition. How the incoherent characteristics arise is described using a Bloch wave approach and examples are shown on interfaces in semiconductor and superconductor materials. 34 refs., 13 figs.

  12. Research Progress on Intercalation Composite Materials based on Kaolin

    Microsoft Academic Search

    Pan Xiaobing; Li Yanfeng; Liu Gang; Men Xuehu

    2004-01-01

    Kaolin is a nonmetal resource with abundant storage, and it would be changed into one of organic\\/inorganic composite materials by means of intercalating modification. Comparing with general composite materials, intercalation composite material is formed by intercalating one or more layers either organic molecules or polymers into inorganic materials with stratum shape, its mechanical properties could be modified markedly. The characteristics

  13. Chemical composition of lake sediments along a pollution gradient in a Subarctic watercourse

    Microsoft Academic Search

    Vladimir Dauvalter; Nikolay Kashulin; Sergey Sandimirov; Petr Terentjev; Dmitry Denisov; Per-Arne Amundsen

    2011-01-01

    Sediment cores were collected from seven lakes in the Subarctic Pasvik watercourse, polluted by sewage waters and air emissions from the Pechenganickel Metallurgical Company, in order to study chemical composition and estimate the intensity of pollution by taking into account background concentration of elements and the vertical and spatial distribution of their contents in cores and surficial layers of sediments.

  14. The Development of Low-Cost Integrated Composite Seal for SOFC: Materials and Design Methodologies

    SciTech Connect

    Xinyu Huang; Kristoffer Ridgeway; Srivatsan Narasimhan; Serg Timin; Wei Huang; Didem Ozevin; Ken Reifsnider

    2006-07-31

    This report summarizes the work conducted by UConn SOFC seal development team during the Phase I program and no cost extension. The work included composite seal sample fabrication, materials characterizations, leak testing, mechanical strength testing, chemical stability study and acoustic-based diagnostic methods. Materials characterization work revealed a set of attractive material properties including low bulk permeability, high electrical resistivity, good mechanical robustness. Composite seal samples made of a number of glasses and metallic fillers were tested for sealing performance under steady state and thermal cycling conditions. Mechanical testing included static strength (pull out) and interfacial fracture toughness measurements. Chemically stability study evaluated composite seal material stability after aging at 800 C for 168 hrs. Acoustic based diagnostic test was conducted to help detect and understand the micro-cracking processes during thermal cycling test. The composite seal concept was successfully demonstrated and a set of material (coating composition & fillers) were identified to have excellent thermal cycling performance.

  15. IR spectroscopic study of the chemical composition of epiphytic lichens

    NASA Astrophysics Data System (ADS)

    Meysurova, A. F.; Khizhnyak, S. D.; Pakhomov, P. M.

    2011-11-01

    Changes in the chemical composition of lichens exposed to pollutants are investigated by means of FTIR spectroscopy. According to model experiments, alkyl nitrates, ammonium salts, amines, and sulfones develop in the lichen thallus through the action of ammonia and nitric and sulfuric acids. Spectroscopic data of modeling experiments enabled nitrogen- and sulfur-containing substances to be identified as the main air pollutants in the vicinity of a pig-breeding complex and information to be obtained on the content of the pollutants and their impact on the lichens.

  16. Fracture problems in composite materials

    NASA Technical Reports Server (NTRS)

    Erdogan, F.

    1972-01-01

    A series of fracture problems in composite materials are identified, their methods of solution are briefly discussed, and some sample results are presented. The main problem of interest is the determination of the stress state in the neighborhood of localized imperfections such as cracks and inclusions which may exist in the composite. Particular emphasis is placed on the evaluation of quantities such as the stress intensity factors, the power of the stress singularity, and the strain energy release rate, which may be used directly or indirectly in connection with an appropriate fracture criterion for the prediction of fracture initiation and propagation load levels. The topics discussed include a crack in layered composites, a crack terminating at and going through a bi-material interface, a penny-shaped crack in a filament-reinforced elastic matrix, and inclusion problems in bonded materials.

  17. Impact of modifying tea–biscuit composition on phytate levels and iron content and availability

    Microsoft Academic Search

    D. Vitali; I. Vedrina Dragojevi?; B. Šebe?i?; L. Vuji?

    2007-01-01

    The effect of modifying the standard recipe of wheat flour based tea–biscuit on phytate levels, iron content and in vitro availability was investigated. Standard recipe was enriched by addition of dietary fibers and integral raw materials. The average phytic acid content of investigated biscuits ranged from 0.138 to 1.084g\\/100g dry matter of biscuit, depending on biscuit composition. Phytic acid levels

  18. Composite Materials for Wind Power Turbine Blades

    Microsoft Academic Search

    Povl Brøndsted; Hans Lilholt; Aage Lystrup

    2005-01-01

    Renewable energy resources, of which wind energy is prominent, are part of the solution to the global energy problem. Wind turbine and the rotorblade concepts are reviewed, and loadings by wind and gravity as important factors for the fatigue performance of the materials are considered. Wood and composites are discussed as candidates for rotorblades. The fibers and matrices for composites

  19. Composite material impregnation unit

    NASA Technical Reports Server (NTRS)

    Wilkinson, S. P.; Marchello, J. M.; Johnston, N. J.

    1993-01-01

    This memorandum presents an introduction to the NASA multi-purpose prepregging unit which is now installed and fully operational at the Langley Research Center in the Polymeric Materials Branch. A description of the various impregnation methods that are available to the prepregger are presented. Machine operating details and protocol are provided for its various modes of operation. These include, where appropriate, the related equations for predicting the desired prepreg specifications. Also, as the prepregger is modular in its construction, each individual section is described and discussed. Safety concerns are an important factor and a chapter has been included that highlights the major safety features. Initial experiences and observations for fiber impregnation are described. These first observations have given great insight into the areas of future work that need to be addressed. Future memorandums will focus on these individual processes and their related problems.

  20. Carbon-Carbon Composite Materials for Friction Purposes

    Microsoft Academic Search

    Igor V. Gurin; I. M. Neklyudov; S. G. Fursov

    2001-01-01

    Results of studies presented are aimed at developing brake disks for aeroplanes, automobiles, and other spheres of application using thermal-gradient gas-phase methods for compaction. An equation is suggested making it possible to calculate the maximum final density of carbon-carbon composite materials prepared by thermal-gradient gas-phase methods, in relation to the specific content and density of the filler. Results are given

  1. Graphite immobilisation in iron phosphate glass composite materials produced by microwave and conventional sintering routes

    NASA Astrophysics Data System (ADS)

    Mayzan, M. Z. H.; Stennett, M. C.; Hyatt, N. C.; Hand, R. J.

    2014-11-01

    An investigation of microwave and conventional processing of iron phosphate based graphite glass composite materials as potential wasteforms for the immobilisation of irradiated graphite is reported. For the base iron phosphate glass, full reaction of the raw materials and formation of a glass melt occurs with consequent removal of porosity at 8 min microwave processing. When graphite is present, iron phosphate crystalline phases are formed with higher levels of residual porosity than in the sample prepared using conventional sintering under argon. It is found that graphite reacts with the microwave field when in powder form but this reaction is minimised when the graphite is incorporated into a pellet, and that the graphite also impedes sintering of the glass. Mössbauer spectroscopy indicates that reduction of iron also occurs with concomitant graphite oxidation. Conventionally sintered samples had lower porosities than the equivalent microwaved ones.

  2. The effect of metal content on the erosion resistance of metal/ceramic co-sprayed composite coatings produced by VPS

    SciTech Connect

    Ramm, D.A.J.; Clyne, T.W. [Univ. of Cambridge (United Kingdom); Sturgeon, A.J.; Dunkerton, S. [TWI, Cambridge (United Kingdom)

    1994-12-31

    Coatings with a range of metal/ceramic contents have been produced by co-spraying of alumina and aluminum, using the Vacuum Plasma Spraying Technique. Attention has been concentrated on ceramic-rich composites containing up to 40% of metal. The resistance of these coatings to erosive wear has been studied, using large silica particles as the erodent, at high and low impingement angles. It is shown that there is scope for the development of composite formulations with good erosion performance over a range of erodent incident angles. These results have been correlated with microstructural characterization and Young modulus measurements, made before and after Hot isostatic Pressing. The composites have higher porosity contents, but also higher stiffness, when compared with the monolithic coatings. This is tentatively explained in terms of an improvement in intersplat bonding being effected by the presence of the metal.

  3. Effect of different growth stages of Ziziphora clinopodioides Lam. on its chemical composition

    PubMed Central

    Ding, Wenhuan; Yang, Tao; Liu, Feng; Tian, Shuge

    2014-01-01

    Aims: The aim of this study is to monitor the changes in the chemical composition of Ziziphora clinopodioides Lam. throughout nine different growth stages. Materials and Methods: Volatile components such as essential oils were analyzed using the gas chromatography (GC) and GC-mass spectrometry, and the contents of non-volatile components were determined by a visible spectrophotometer. Results: Hydro-distilled essential oil content ranged from a minimum of 1.1% (in the post-flowering stage) to a maximum of 1.8% (in the flowering stage). The essential oils included pulegone, which was the most abundant component (77.48-87.3%), p-menthanone (2.79-12.39%), trans-isopulegone (1.04-2.06%), d-limonene (0.51-3.03%) and eucarvone (1.5-4.48%). The contents of non-volatile components, such as that of total phenolics (TPC), total flavonoids (TFC), total triterpenoids content (TTC) and total free amino acids content (TFAAC) were measured using visible spectrophotometry. In the growing stage, TPC, TFC, TTC and TFAAC were 9.91-12.80 mg/g, 29.84-50.63 mg/g, 0.57-1.41 mg/g and 13.33-28.56 mg/g, respectively. Conclusion: These data can be used as a basis to determine the optimal harvest time of Z. clinopodioide Lam. PMID:24914287

  4. Fabrication of a nanostructured gold-polymer composite material

    NASA Astrophysics Data System (ADS)

    Mallick, K.; Witcomb, M.; Scurrell, M.

    2006-07-01

    A facile synthesis route is described for the preparation of a poly-(o-aminophenol)-gold nanoparticle composite material by polymerization of o-aminophenol (AP) monomer using HAuCl4 as the oxidant. The synthesis was carried out in a methanol medium so that it could serve a dual solvent role, a solvent for both the AP and the water solution of HAuCl4. It was found that oxidative polymerization of AP leads to the formation of poly-AP with a diameter of 50±10nm, while the reduction of AuCl4- results in the formation of gold nanoparticles (˜ 2nm). The gold nanoparticles were uniformly dispersed and highly stabilized throughout the macromolecular chain that formed a uniform metal-polymer composite material. The resultant composite material was characterized by means of different techniques, such as UV-vis, IR and Raman spectroscopy, which offered the information about the chemical structure of polymer, whereas electron microscopy images provided information regarding the morphology of the composite material and the distribution of the metal particles in the composite material.

  5. Impact response of composite materials

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Srinivasan, K.

    1991-01-01

    Composite materials composed of carbon fibers and resin matrices offer great promise in reducing the weight of aerospace structures. However they remain extremely vulnerable to out of plane impact loads, which lead to severe losses in strength and stiffness. The results of an experimental program, undertaken to investigate the low velocity impact damage tolerance of composite materials is presented. The objectives were to identify key neat resin/composite properties that lead to enhancement of composite impact damage tolerance and to find a small scale test that predicts compression after impact properties of panels. Five materials were selected for evaluation. These systems represented different classes of material behavior such as brittle epoxy, modified epoxies, and amorphous and semicrystalling thermoplastics. The influence of fiber properties on the impact performance was also studied in one material, i.e., in polyether ether ketone (PEEK). Several 24 and 48 ply quasi-isotropic and 24 ply orthotropic laminates were examined using an instrumented drop weight impactor. Correlations with post impact compression behavior were made.

  6. Acoustic emission monitoring of polymer composite materials

    NASA Technical Reports Server (NTRS)

    Bardenheier, R.

    1981-01-01

    The techniques of acoustic emission monitoring of polymer composite materials is described. It is highly sensitive, quasi-nondestructive testing method that indicates the origin and behavior of flaws in such materials when submitted to different load exposures. With the use of sophisticated signal analysis methods it is possible the distinguish between different types of failure mechanisms, such as fiber fracture delamination or fiber pull-out. Imperfections can be detected while monitoring complex composite structures by acoustic emission measurements.

  7. Composite materials with improved phyllosilicate dispersion

    DOEpatents

    Chaiko, David J.

    2004-09-14

    The present invention provides phyllosilicates edge modified with anionic surfactants, composite materials made from the edge modified phyllosilicates, and methods for making the same. In various embodiments the phyllosilicates are also surface-modified with hydrophilic lipophilic balance (HLB) modifying agents, polymeric hydrotropes, and antioxidants. The invention also provides blends of edge modified phyllosilicates and semicrystalline waxes. The composite materials are made by dispersing the edge modified phyllosilicates with polymers, particularly polyolefins and elastomers.

  8. Chemical compatibility of cartridge materials

    NASA Technical Reports Server (NTRS)

    Ambrose, Bryan; Wilcox, R. C.; Zee, R. H.

    1992-01-01

    The objectives were to determine the chemical compatibility of titanium-zirconium-molybdenum (TZM) with GaAs and CdZnTe, and Inconel with HgCdTe and HgZnTe. At the present time, no other studies regarding the compatibility of these crystal components and their respective cartridge materials have been performed. This study was to identify any possible problems between these materials to insure proper containment of possibly hazardous fumes during crystal growth experiments. In this study, the reaction zone between the materials was studied and the amount of degradation to the system was measured. Detailed results are presented.

  9. Reduction study of oxidized two-dimensional graphene-based materials by chemical and thermal reduction methods

    NASA Astrophysics Data System (ADS)

    Douglas, Amber M.

    Graphene is a two-dimensional (2D) sp2-hybridized carbon-based material possessing properties which include high electrical conductivity, ballistic thermal conductivity, tensile strength exceeding that of steel, high flexural strength, optical transparency, and the ability to adsorb and desorb atoms and molecules. Due to the characteristics of said material, graphene is a candidate for applications in integrated circuits, electrochromic devices, transparent conducting electrodes, desalination, solar cells, thermal management materials, polymer nanocomposites, and biosensors. Despite the above mentioned properties and possible applications, very few technologies have been commercialized utilizing graphene due to the high cost associated with the production of graphene. Therefore, a great deal of effort and research has been performed to produce a material that provides similar properties, reduced graphene oxide due (RGO) to the ease of commercial scaling of the production processes. This material is typically prepared through the oxidation of graphite in an aqueous media to graphene oxide (GO) followed by reduction to yield RGO. Although this material has been extensively studied, there is a lack of consistency in the scientific community regarding the analysis of the resulting RGO material. In this dissertation, a study of the reduction methods for GO and an alternate 2D carbon-based material, humic acid (HA), followed by analysis of the materials using Raman spectroscopy and Energy Dispersive X-ray Spectroscopy (EDS). Means of reduction will include chemical and thermal methods. Characterization of the material has been carried out on both before and after reduction.

  10. 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

  11. Composite materials: composition, properties and clinical applications. A literature review.

    PubMed

    Zimmerli, Brigitte; Strub, Matthias; Jeger, Franziska; Stadler, Oliver; Lussi, Adrian

    2010-01-01

    Various composite materials are available today for direct restorative techniques. The most well-known materials are the hybrid composites. This technology, based on methacrylates and different types of filler coupled with silanes, has been continuously improved. Disadvantages such as polymerisation shrinkage, bacterial adhesion and side effects due to monomer release still remain. The aim of material development is to eliminate or at least reduce these negative factors by adapting the individual components of the material. With ormocers, the methacrylate has been partially replaced by an inorganic network. According to recent studies, the biocompatibility was not improved in all cases. The development of compomer was an attempt to combine the positive properties of glassionomers with composite technology. This has only partially succeeded, because the fluoride release is low. In an in-situ study, a caries protective effect could be shown at least in the first days following filling placement with concurrent extra-oral demineralisation. By replacing the chain-monomers in the composite matrix by ring-shaped molecules, a new approach to reduce polymerisation shrinkage was investigated. A new group of materials, the siloranes, has been developed. Siloranes are hydrophobic and need to be bonded to the dental hard tissue using a special adhesive system. Long-term clinical studies are still needed to prove the superiority of this new group of materials over modern hybrid composites. PMID:21243545

  12. Kevlar fiber-epoxy adhesion and its effect on composite mechanical and fracture properties by plasma and chemical treatment

    SciTech Connect

    Shyu, S.S.; Wu, S.R.; Sheu, G.S. [National Central Univ., Chung-Li (Taiwan, Province of China)

    1996-12-31

    Kevlar 49 fibers were surface modified by gas (ammonia, oxygen, and water vapor) plasmas etching and chlorosulfonation and subsequent reaction with some reagents (glycine, deionized water, ethylenediamine, and 1-butanol) to improve the adhesion to epoxy resin. After these treatments, the changes in fiber topography, chemical compositions of the fiber surfaces and the surface functional groups introduced to the surface of fibers were identified by SEM XPS and static SIMS. Interlaminar shear strength (ILSS) and T-peel strength between the fiber and epoxy resin were markedly improved by gas plasma and chlorosulfonation (0.1% and 0.25% ClSO{sub 3}H at 30 s). However, it is clear from the similar G{sub IC} values of the treated and untreated fiber composites that the fiber/matrix interfacial bond strength is only a minor contributor to G{sub IC}. SEM was also used to study the surface topography of the fracture surfaces of composites in T-peel test.

  13. Templated Chemically Deposited Semiconductor Optical Fiber Materials

    NASA Astrophysics Data System (ADS)

    Sparks, Justin R.; Sazio, Pier J. A.; Gopalan, Venkatraman; Badding, John V.

    2013-07-01

    Chemical deposition is a powerful technology for fabrication of planar microelectronics. Optical fibers are the dominant platform for telecommunications, and devices such as fiber lasers are forming the basis for new industries. High-pressure chemical vapor deposition (HPCVD) allows for conformal layers and void-free wires of precisely doped crystalline unary and compound semiconductors inside the micro-to-nanoscale-diameter pores of microstructured optical fibers (MOFs). Drawing the fibers to serve as templates into which these semiconductor structures can be fabricated allows for geometric design flexibility that is difficult to achieve with planar fabrication. Seamless coupling of semiconductor optoelectronic and photonic devices with existing fiber infrastructure thus becomes possible, facilitating all-fiber technological approaches. The deposition techniques also allow for a wider range of semiconductor materials compositions to be exploited than is possible by means of preform drawing. Gigahertz bandwidth junction-based fiber devices can be fabricated from doped crystalline semiconductors, for example. Deposition of amorphous hydrogenated silicon, which cannot be drawn, allows for the exploitation of strong nonlinear optical function in fibers. Finally, crystalline compound semiconductor fiber cores hold promise for high-power infrared light-guiding fiber devices and subwavelength-resolution, large-area infrared imaging.

  14. Chemical Composition of Laboratory Generated Seafoam Particles

    NASA Astrophysics Data System (ADS)

    Tyree, C. A.; Alexandrova, O. A.; Allen, J. O.

    2005-12-01

    Remote marine aerosols include a significant number of sea-salt particles that may be effective cloud condensation nuclei. For example, O`Dowd and Smith (1993) found that remote marine aerosols in the particle size range 0.1-3.0 ?m were dominated by sea-salt particles in the case of moderate-to-high wind speeds. Measurements of the flux of sub-micron sea-salt particles for the same wind speed vary by orders of magnitude, which indicate that other parameters, for example, may have a role in their production (Reid et al., 2001). Previous laboratory experiments using artificial seawater have shown that organic content (Garrett, 1968) and salinity (Mortensson et al., 2003) affect sea-salt particle production. We present laboratory measurements of sea-salt particles generated from seawater foams and compare them to measurements of remote marine particles. Foam droplets were generated by bubbling air through a fine pore diffuser into aqueous media in a precleaned glass column. The effect of salinity was studied by varying the salinity of artificial seawater over the range 0-3.5%. The effect of organic content was also studied by diluting filtered seawater with artificial seawater. Size distributions of dried seafoam droplets were measured using a scanning mobility particle sizer. Seafoam particles were also size segregated and collected using a Micro-Orifice Uniform Deposit Impactor. Collected material was analyzed for sodium, chloride, sulfate, and dissolved organic carbon (DOC). Sub-micron particle size distributions were unimodal with a mean diameter of ~100 nm in agreement with recent seafoam laboratory experiments (Martensson et al., 2003). This mode is comparable to the "accumulation" mode particles typical of the remote marine environment and known to contain significant amounts of sea-salt (Bates et al., 1998). The size and number of seafoam particles were dependent on salinity; mean droplet size and total number concentration increased with salinity. Surprisingly, the size and number of seafoam particles was independent of organic content; this is in contrast to previous laboratory experiments that showed seafoam particle numbers were enhanced when surface-active organics were added to artificial seawater (Garrett, 1968). We present recent measurements of the composition and enrichment of laboratory seafoam particles, which we propose approximate remote marine boundary layer particles.

  15. Understanding chemical trends in rock surface compositions as measured by ChemCam at Gale crater, Mars: The signatures of rock coatings and rinds in LIBS laboratory data

    NASA Astrophysics Data System (ADS)

    Lanza, N.; Clegg, S. M.; Wiens, R. C.; Leveille, R. J.; Melikechi, N.; Ollila, A.; Tokar, R. L.; Newsom, H. E.; Blank, J. G.; Bridges, N. T.; Clark, B.; Deans, M. C.; Delapp, D.; Ehlmann, B. L.; Hardgrove, C. J.; Jackson, R.; Lasue, J.; McInroy, R.; Meslin, P.; Mezzacappa, A.; Team, M.

    2013-12-01

    On Earth, the physical and chemical breakdown of rocky materials occurs through interactions with the atmosphere, soil, biological processes, and aqueous solutions. These interactions produce alteration features on the surfaces of rocks, which record information about the amount and types of fluids with which the rock has interacted. Alteration features can also be indicators of and habitats for microbial life in terrestrial environments. Thus, detecting rock surface alteration is an important part of the NASA Curiosity rover mission to Gale crater, Mars. The ChemCam LIBS instrument onboard Curiosity is uniquely suited to detecting and analyzing rock surface alteration. The LIBS technique uses a pulsed laser microbeam (350-550 ?m) to ablate small amounts of material from a target to form a plasma. Because some material is removed during each laser pulse, it is possible to obtain a depth profile of chemical composition by performing multiple laser pulses on one location. Each pulse returns a spectrum that represents the composition at a specific depth, with each subsequent shot sampling the composition at a slightly greater depth. Laboratory measurements of basalts have shown that each LIBS shot removes at least ~0.3-0.82 ?m/shot, suggesting a removal of ~9-25 ?m of the surface for a standard analysis of 30 shots in rocks of similar hardness. Here we present laboratory LIBS experiments on well-characterized terrestrial rock samples with coatings and rinds with the goal of understanding the signatures of such features in LIBS data from Mars. The terrestrial sample set includes a basalt with a ~0-50 ?m thick Mn-rich rock varnish and a thin (<1 mm) weathering rind and a sandy dolomite with a ~500 ?m thick Ca-rich rind. Both samples were interrogated with hundreds of LIBS shots per location three times on the unweathered interior and three times on the exterior. Results from the basalt show that compositions similar to the bulk rock composition was reached by ~50-70 shots, with the observed chemical changes suggesting both the varnish and at least some rind were penetrated. Results from the sandy dolomite do not show as clear a change from rock exterior to interior as the basalt, but a general chemical trend from exterior to interior was observed in all three depth profiles. Laboratory results suggest that depth profiles of at least 100 shots are useful for clearly identifying coatings and rinds of similar thickness to those found on Earth. However, alteration trends may still be discernible with fewer shots. On Mars, the rock Bathurst Inlet (sol 55), which was shot only 30 times per location, shows what appears to be a near-surface gradient of several elements, most notably Li. Trends similar in nature (if not composition) to the terrestrial sandy dolomite sample were also observed on raised ridge materials such as McGrath_5 (sol 234). Additional martian samples also show trends similar to coatings and rinds measured in the laboratory, suggesting that there may be surface alteration of some rocks in Gale crater.

  16. Influence of coal briquetting conditions on the chemical composition of the products of thermal degradation

    SciTech Connect

    Turenko, F.P.

    1984-01-01

    A spectro-statistical method was used to examine the chemical composition of liquid non-volatile constituents from a mixture of Donbass coals (gas, fat, lean, caking). The thermal destruction products obtained by thermal filtration in a centrifugal field from both briquetted and non-briquetted charges differ in terms of their structural group content.

  17. Chemical composition of sediments from White Sea, Russian Arctic

    NASA Astrophysics Data System (ADS)

    Gamza, Olga; Shevchenko, Vladimir; Novigatsky, Aleksandr

    2010-05-01

    The White Sea, the only Russian inland sea, is located on the north of outlying districts of the European part of Russia, belongs to Arctic Ocean. Area of water of sea occupies about 90 tousend square kilometers. The sea can be divided into some general parts: neck, funnel, basin and 4 Bays: Dvina Bay, Kandalaksha Bay, Mezen Bay and Onega Bay. The purpose of this work was geochemical mapping of the surface sediments of this area. The main tasks were: compilation data base of element composition of the surface sediments, geochemical mapping of each element, research of the anormal concentration of elements on the surface. To detect the content of chemical elements several methods were used: atomic absorption spectrometry (P.P. Shirshov Institute of Oceanology); neutron activation analysis (Vernadsky Institute of Geochemistry and Analytical Chemistry), total and organic carbon analysis, photometric method to detection Si, Al, P (P.P. Shirshov Institute of Oceanology). Bulk composition is one of the fundamental characteristics of sediments and bottom deposites of modern basins. Coarse-grained sediments with portion of pelitic component <50% is spread on the shallow area (Kandalaksha Bay), in areas with high hydrodynamic activity of near-bottom water. Under the conditions of their low activity, fine-grained facies are common(>80%). Character of elements distribution correlates with facial distribution of sediments from White Sea. According to litologic description, bottom surface of Dvina Bay is practically everywhere covered by layer of fine-grained sand. In the border area between Dvina Bay and White Sea basin on terraced subwater slope aleurite politic silts are abundant. They tend to exhange down the slope to clay silts. In Onega Bay fractions of non-deposition are observed. They are characterized by wide spread of thin blanket poorgraded sediments, which are likely to be relic. Relief of Kandalakscha Bay bottom is presented as alternation of abyssal fosses (near 300 m) with silles and elevations (<20 m), and also numerous islands. Thus variety of sediment composition is observed here - from rules and gravels to fine-grained clay silts [1]. The map of distribution of chemical elements was created by using bulk composition data with the help of program ArcView. Mn distribution in sedimentation mass is largely determed by influence of redox diagenesis. Reactive form of Mn dominates over less moving, litogenic form in sedimation mass of White Sea. Litogenic form remains in sediment, reactive form moves into silt near-bottom water, resulting Mn migration both in sediment and near-bottom layer of marine water. Mn oxidizes on the contact with oxygen of marine water and alters into insoluble form MnO2, causing Mn enrichment of surface layer of sediments. Highly movable silt deposit MnO2 and enriched by Mn suspension are moved by underflow and accumulate in bottom depressions and in central part of the sea, which is quite wide from both places of original sedimentation and run off sources [2]. Thus, the interrelation between granulometric composition of sediment and materials concentration can be shown by the example of Mn. Local conditions, leading to accumulation of clastic components, are: 1. Rise of content in sand owning to separation of heavy minerals 2. Rise of content in surface, mainly sandy clay sediments owning to presence of concretions 3. Rise of content in lower bunches roof owning to diagenetic contraction. Authors thank academic Lisitsyn for encourage, Andrey Apletalin for valuable help, and everybody, who helped in field and laboratory research of the White sea sediments. Work was being done under the auspices of Russian foundation of basic research (grants 09-05-10081, 09-05-00658 and 08-05-00860), RSA presidiums program of 17 fundamental researches (project 17.1). References: 1.Kuzmina T., Lein A., Lutchsheva L., Murdmaa I., Novigatsky A., Shevchenko V. Chemical composition of White Sea's sediments // Litology and mineral deposits . 2009. - ? 2. - P 115-132. 2.Nevessky E., Medvedev V. , Kalin

  18. ADVANCED COMPOSITE MATERIALS HEAT BRIDGES

    Microsoft Academic Search

    A. B. Shopen; V. A. Golovanevskiy; O. A. Kivirenko

    Understanding heat transfer properties of advanced composite materials (CM) structures is gaining increasing importance in industries such as medicine and cryogenics, aerospace and electronics where structures made from advanced CM are being used as heat bridges. The main goal in such applications of advanced CM structures is achieving maximum load bearing capacity while maintaining heat transfer rate at a predetermined

  19. Durability of polymer composite materials

    Microsoft Academic Search

    Liu Liu

    2006-01-01

    The purpose of this research is to examine structural durability of advanced composite materials under critical loading conditions, e.g., combined thermal and mechanical loading and shear fatigue loading. A thermal buckling model of a burnt column, either axially restrained or under an axial applied force was developed. It was predicted that for a column exposed to the high heat flux

  20. Temperature and chemical composition of droplets by optical measurement techniques: a state-of-the-art review

    NASA Astrophysics Data System (ADS)

    Lemoine, Fabrice; Castanet, Guillaume

    2013-07-01

    The measurement of the sizes and the velocities of droplets relies upon widespread and well-established techniques, but characterizing their temperature and their composition remains challenging. The lack of standard methods is particularly detrimental, given the importance of these parameters for validating models and numerical simulations of many spray processes. Heat and mass transfers are dominant aspects in applications such as spray combustion in IC engines, spray cooling, spray drying, wet scrubbers in which liquid sprays capture gas pollutants and also the preparation of nanoparticles via spray route. This paper provides a review of the main techniques available to optically measure the temperature and chemical compositions of single droplets and sprays. Most of these techniques are based on phenomena related to light interaction with matter. Photoluminescence processes like fluorescence and phosphorescence have temperature and composition dependences which can be exploited, while other methods rely on light scattering by the droplets. In particular, the angular position of the rainbow is very sensitive to the refractive index and then to both the temperature and composition. Less widely used diagnostic methods include Raman scattering, thermochromic liquid crystals, thermographic phosphors, infrared thermography, morphology-dependent resonances and their subsequent effects on the stimulated emission of dye molecules. In this review, the emphasis is mainly placed on two groups of techniques—methods based on laser-induced fluorescence and those based on light scattering—but details about alternative methods will be also provided. The potential of combining fluorescence-based techniques or rainbow refractometry with a droplet sizing measurement technique to derive temperature and composition per size class will be also discussed.

  1. Chemical composition studies of flint with different origins

    NASA Astrophysics Data System (ADS)

    Zarina, Liga; Seglins, Valdis; Kostjukovs, Juris; Burlakovs, Juris

    2015-04-01

    Flint is a widely used material in the Stone Age because of its physical characteristics, which makes the material suitable for obtaining tools with sharp working edges. Chert, flint, chalcedony, agate and jasper in composition and several other physical characteristics are very similar. Therefore in archaeology most often they are determined simplified and are not distinguished, but described as flint or chert, denoting only the material in a general sense. However, in-depth studies it is necessary accurately identify the rock type and, in addition, to determine the origin of the flint and the conditions of the formation for the various archaeological research needs. As a typical example can be noted the localization problems in determining whether flint is local, or have emerged in the region through the exchange or by transportation. Flint consists mainly from quartz and mostly it has cryptocrystalline or amorphous structure. In nature it occurs as nodules and interbedded inclusions in sedimentary deposits as a result of digenesis processes when calcium carbonate is replaced with silicia. Bedded chert primarily is accumulations originated from excess alkalinity in the sediments. Flint can also be formed in the crystallization processes of the chemically unstable amorphous silicia. In this context, it should be noted that flint is naturally heterogeneous and very varied material by the physical properties and therefore problematic in many contemporary studies. In the study different origin flint samples from England, Denmark and Latvia were compared after their chemical composition. Flint nodules from Northern Europe chalk cliffs formed as inclusions in interbedded deposits or results of the digenesis and samples of chalcedony saturated dolomite from Latvia formed in hydrothermal processes were analysed using XRD and XRF methods. The obtained data were statistically analysed, identifying major, minor and trace elements and subsequently assessing the chemical composition characteristics of the various origins flint. The obtained data indicates that in the flint nodules the amount of silicia is large and relatively stable, as well the presence of other chemical elements are uniform and relatively homogeneous. In turn, in the chalcedony saturated dolomite can be observed the highly variable quantity of silicia, the unstable proportion of Ca-Mg and other key chemical elements and the constantly present rare earth elements, whose concentration can be significant. The performed analysis confirmed that with the chemical composition analysis it is possible to distinguish flint formed in the different geological conditions, as well as to evaluate the indicative characteristics.

  2. acACS: Improving the Prediction Accuracy of Protein Subcellular Locations and Protein Classification by Incorporating the Average Chemical Shifts Composition

    PubMed Central

    Liu, Yan-Ling; Mei, Han-Xue; Rang, Yi; Hou, Bao-Yan; Zhao, Yan

    2014-01-01

    The chemical shift is sensitive to changes in the local environments and can report the structural changes. The structure information of a protein can be represented by the average chemical shifts (ACS) composition, which has been broadly applied for enhancing the prediction accuracy in protein subcellular locations and protein classification. However, different kinds of ACS composition can solve different problems. We established an online web server named acACS, which can convert secondary structure into average chemical shift and then compose the vector for representing a protein by using the algorithm of auto covariance. Our solution is easy to use and can meet the needs of users. PMID:25110749

  3. Detection of exposure damage in composite materials using Fourier transform infrared technology

    Microsoft Academic Search

    Dennis Patrick Roach; Randy L. Duvall

    2010-01-01

    Goal: to detect the subtle changes in laminate composite structures brought about by thermal, chemical, ultraviolet, and moisture exposure. Compare sensitivity of an array of NDI methods, including Fourier Transform Infrared Spectroscopy (FTIR), to detect subtle differences in composite materials due to deterioration. Inspection methods applied: ultrasonic pulse echo, through transmission ultrasonics, thermography, resonance testing, mechanical impedance analysis, eddy current,

  4. Carbon Nano Tube Composites with Chemically Functionalized Plant Oils

    NASA Astrophysics Data System (ADS)

    Thielemans, Wim; Wool, Richard P.; Blau, Werner; Barron, Valerie

    2003-03-01

    Carbon Nano Tube Composites with Chemically Functionalized Plant Oil Wim Thielemans, R., P. Wool, V. Barron and W. Blau Multi-Wall Carbon Nano Tubes (MWCNT) made by the Kratchmer-Huffman CCVD process were found to interact and solubilize by slow mechanical stirring, with chemically functionalized plant oils, such as acrylated, epoxidized and maleinated triglycerides (TG) derived from plant oils. The chemical functionality on the TG imparted amphiphilic properties to the oils which allows them to self-assemble on the nanotubes, promoting both dissolution and the ability to make nanocomposites with unusual properties. Once in solution, the MWCT can be processed in a variety of methods, in particular to make composites with enhanced mechanical, fracture and thermal properties. Since the tensile modulus of MWs is about 1 TPa and a vector percolation analysis indicated tensile strengths of 50-100 GPa, we obtain significantly improved properties with even small amounts (1-3the glass transition temperature of the composite by about 20 oC, and the tensile modulus by about 11significant effects on the fracture stress can be obtained due to the both the influence of the strength and length of the MWNT at the crack tip. The ability of the oils to self-assemble on the carbon nanotube surfaces also makes them ideal candidates for self-healing materials. The properties with different functionalized oils will be reported. Supported by EPA, DoE and ISF

  5. Interfacial interaction and adhesion in composite materials

    Microsoft Academic Search

    R. Y. Yee; E. C. Martin

    1984-01-01

    The interfacial interaction of composites plays an important role in the properties of material such as structural materials, solid propellants, and explosives. To study the interfacial interaction, surface and interfacial free energies were investigated. The wettability of solids was determined by the Wilhelmy plate method using a series of reference liquids. The surface free energies of these solids were calculated

  6. Effect of Sintering Temperature on Thermoelectric Properties of PbTe/Ag Composites Fabricated by Chemical Plating and Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Sie, F. R.; Hwang, C. S.; Tang, Y. H.; Kuo, C. H.; Chou, Y. W.; Yeh, C. H.; Ho, H. Y.; Lin, Y. L.; Lan, C. H.

    2015-06-01

    PbTe/Ag composite powders were synthesized by a chemical plating method and then compacted by spark plasma sintering (SPS) at 573 K to 673 K and 50 MPa. The effects of the sintering temperature on the thermoelectric properties of PbTe and the PbTe/Ag composites were investigated. The thermoelectric properties of PbTe and PbTe/Ag bulk samples were measured in the temperature range from 300 K to 700 K. PbTe/Ag bulk samples changed electrical transport behavior from p-type to n-type at room temperature. The SPS temperature not only changed the lattice parameter but also affected the conduction behavior of PbTe/Ag composites. The variation in the carrier concentration was determined by the role of the Ag dopant for different SPS temperatures. Moreover, the conduction of the PbTe/Ag samples changed from metallic to semiconducting in the measured temperature range from 300 K to 700 K as the sintering temperature increased. For the PbTe/Ag bulk materials subjected to SPS at 573 K and 673 K, the values of the power factor were 0.38 mW/m K2 and 1.31 mW/m K2 at 700 K, respectively.

  7. Production of Copper-Based Rare Earth Composite Metal Materials by Coprecipitation and Applications for Gaseous Ammonia Removal

    Microsoft Academic Search

    Chang-Mao Hung

    2011-01-01

    This study addresses the oxidation of ammonia (NH3) at temperatures between 423 and 673 K by selective catalytic oxidation (SCO) over a copper-based, rare earth composite metal material that was prepared by coprecipitating copper nitrate, lanthanum nitrate, and cerium nitrate at various molar ratios. The catalysts were characterized using Brunner, Emmett, and Teller spectroscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, ultraviolet–visible

  8. Fungal degradation of fiber-reinforced composite materials

    NASA Technical Reports Server (NTRS)

    Gu, J. D.; Lu, C.; Mitchell, R.; Thorp, K.; Crasto, A.

    1997-01-01

    As described in a previous report, a fungal consortium isolated from degraded polymeric materials was capable of growth on presterilized coupons of five composites, resulting in deep penetration into the interior of all materials within five weeks. Data describing the utilization of composite constituents as nutrients for the microflora are described in this article. Increased microbial growth was observed when composite extract was incubated with the fungal inoculum at ambient temperatures. Scanning electron microscopic observation of carbon fibers incubated with a naturally developed population of microorganisms showed the formation of bacterial biofilms on the fiber surfaces, suggesting possible utilization of the fiber chemical sizing as carbon and energy sources. Electrochemical impedance spectroscopy was used to monitor the phenomena occurring at the fiber-matrix interfaces. Significant differences were observed between inoculated and sterile panels of the composite materials. A progressive decline in impedance was detected in the inoculated panels. Several reaction steps may be involved in the degradation process. Initial ingress of water into the resin matrix appeared to be followed by degradation of fiber surfaces, and separation of fibers from the resin matrix. This investigation suggested that composite materials are susceptible to microbial attack by providing nutrients for growth.

  9. Computational modeling of composite material fires

    Microsoft Academic Search

    Alexander L. Brown; Kenneth L. Erickson; Joshua Allen Hubbard; Amanda B. Dodd

    2010-01-01

    Composite materials behave differently from conventional fuel sources and have the potential to smolder and burn for extended time periods. As the amount of composite materials on modern aircraft continues to increase, understanding the response of composites in fire environments becomes increasingly important. An effort is ongoing to enhance the capability to simulate composite material response in fires including the

  10. Structural predictions based on the compositions of cathodic materials by first-principles calculations

    NASA Astrophysics Data System (ADS)

    Li, Yang; Lian, Fang; Chen, Ning; Hao, Zhen-jia; Chou, Kuo-chih

    2015-05-01

    A first-principles method is applied to comparatively study the stability of lithium metal oxides with layered or spinel structures to predict the most energetically favorable structure for different compositions. The binding and reaction energies of the real or virtual layered LiMO2 and spinel LiM2O4 (M = Sc-Cu, Y-Ag, Mg-Sr, and Al-In) are calculated. The effect of element M on the structural stability, especially in the case of multiple-cation compounds, is discussed herein. The calculation results indicate that the phase stability depends on both the binding and reaction energies. The oxidation state of element M also plays a role in determining the dominant structure, i.e., layered or spinel phase. Moreover, calculation-based theoretical predictions of the phase stability of the doped materials agree with the previously reported experimental data.

  11. Preparation and properties of multifunctional nylon 6 composite material

    Microsoft Academic Search

    Lai Chiu-Chun; Jen Chyi-Wen; Chang Yuh-Shyang; Huang Kuo-Shien

    2011-01-01

    We considered polyamide 6 as a base material for a composite and added improved tourmaline and carbon fiber to manufacture a material that could release negative ions and resist electromagnetic waves. Through Fourier transform infrared spectroscopy and thermogravimetric analyses, we verified that the improved tourmaline could disperse homogeneously in the base material, whose thermal properties improved as the content of

  12. Fracture problems in composite materials.

    NASA Technical Reports Server (NTRS)

    Erdogan, F.

    1972-01-01

    In this paper a series of fracture problems in composite materials are identified, their methods of solution are briefly discussed, and some sample results are presented. The main problem of interest is the determination of the stress state in the neighborhood of localized imperfections such as cracks and inclusions which may exist in the composite. Particular emphasis is placed on the evaluation of quantities such as the stress intensity factors, the power of the stress singularity, and the strain energy release rate, which may be used directly or indirectly in connection with an appropriate fracture criterion for the prediction of fracture initiation and propagation load levels.

  13. Self-forming polymer ceramic composite made by an in-situ process to yield superior microstructrue while using materials and energy efficiently

    Microsoft Academic Search

    Carolyn M. Dry

    2001-01-01

    This polymer ceramic composite is biomimetic in that it follows the rules of bone growth for superior properties of strength and toughness. There is an intimate mechanical and chemical bond which is due to the careful growth sequences, i.e., the fibers are made first and the two matrix materials grown around them in sequence. Moreover, it can be grown in-

  14. Layer by Layer Ex-Situ Deposited Cobalt-Manganese Oxide as Composite Electrode Material for Electrochemical Capacitor

    PubMed Central

    Rusi; Chan, P. Y.; Majid, S. R.

    2015-01-01

    The composite metal oxide electrode films were fabricated using ex situ electrodeposition method with further heating treatment at 300°C. The obtained composite metal oxide film had a spherical structure with mass loading from 0.13 to 0.21 mg cm-2. The structure and elements of the composite was investigated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The electrochemical performance of different composite metal oxides was studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (CD). As an active electrode material for a supercapacitor, the Co-Mn composite electrode exhibits a specific capacitance of 285 Fg-1 at current density of 1.85 Ag-1 in 0.5M Na2SO4 electrolyte. The best composite electrode, Co-Mn electrode was then further studied in various electrolytes (i.e., 0.5M KOH and 0.5M KOH/0.04M K3Fe(CN) 6 electrolytes). The pseudocapacitive nature of the material of Co-Mn lead to a high specific capacitance of 2.2 x 103 Fg-1 and an energy density of 309 Whkg-1 in a 0.5MKOH/0.04MK3Fe(CN) 6 electrolyte at a current density of 10 Ag-1. The specific capacitance retention obtained 67% of its initial value after 750 cycles. The results indicate that the ex situ deposited composite metal oxide nanoparticles have promising potential in future practical applications. PMID:26158447

  15. Original article Chemical composition and coagulation properties

    E-print Network

    Paris-Sud XI, Université de

    Original article Chemical composition and coagulation properties of Modicana and Holstein cows composition was the same in both breeds. The pH of the Mo milk was lower (­0.07), coagulation time and curd coagulation du lait des races bovines Modicana et Holstein. La production, la composition chimique et l

  16. Effect of Rhizobium inoculation, organic and chemical fertilizers on proximate composition, in vitro protein digestibility, tannin and sulphur content of faba beans

    Microsoft Academic Search

    Elsiddig A. E. Elsheikh; Abdulhafiz A. Elzidany

    1997-01-01

    A field experiment was carried out to investigate the effect of Rhizobium inoculation, sulphur, nitrogen and chicken manure on proximate analysis, in vitro protein digestibility (IVPD) tannin and sulphur content of faba beans. The results showed that Rhizobium inoculation, sulphur, nitrogen and chicken manure treatments significantly (P ? 0.05) increased protein, IVPD and tannin content. Ash, moisture, fat and crude

  17. The Chemical Composition of Martian Soil and Rocks Returned by the Mobile Alpha Proton X-ray Spectrometer: Preliminary Results from the X-ray Mode

    NSDL National Science Digital Library

    R. Rieder

    This article presents the chemical composition of six soils and five rocks at the Ares Vallis landing site obtained by the alpha proton x-ray spectrometer on board the rover of the Mars Pathfinder mission. The analyzed rocks were compositionally similar to each other, but were unexpectedly high in silica and potassium and low in magnesium compared to previously studied Martian soils and meteorites. The analyzed rocks are similar in composition to terrestrial andesites and close to the mean composition of Earth's crust. Soil analyses appear similar to those determined by the Viking missions.

  18. Shifting material source of Chinese loess since ~2.7 Ma reflected by Sr isotopic composition.

    PubMed

    Zhang, Wenfang; Chen, Jun; Li, Gaojun

    2015-01-01

    Deciphering the sources of eolian dust on the Chinese Loess Plateau (CLP) is fundamental to reconstruct paleo-wind patterns and paleo-environmental changes. Existing datasets show contradictory source evolutions of eolian dust on the CLP, both on orbital and tectonic timescales. Here, the silicate Sr and Nd isotopic compositions of a restricted grain size fraction (28-45??m) were measured to trace the source evolution of the CLP since ~2.7?Ma. Our results revealed an unchanged source on orbital timescales but a gradual source shift from the Qilian Mountains to the Gobi Altay Mountains during the past 2.7?Ma. Both tectonic uplift and climate change may have played important roles for this shift. The later uplift of the Gobi Altay Mountains relative to the Qilian Mountains since 5?±?3?Ma might be responsible for the increasing contribution of Gobi materials to the source deserts in Alxa arid lands. Enhanced winter monsoon may also facilitate transportation of Gobi materials from the Alxa arid lands to the CLP. The shifting source of Asian dust was also reflected in north Pacific sediments. The finding of this shifting source calls for caution when interpreting the long-term climate changes based on the source-sensitive proxies of the eolian deposits. PMID:25996645

  19. Nonmetallic materials and composites at low temperatures

    SciTech Connect

    Hartwig, G.; Evans, D.

    1982-01-01

    This book presents articles by leading scientists who explore the cryogenic behavior of such materials as epoxies, polyethylenes, polymers, various composites, and glasses. Examines the thermal and dielectric properties of these materials, as well as their elasticity, cohesive strength, resistance to strain and fracturing, and applications. Topics include thermal properties of crystalline polymers; thermal conductivity in semicrystalline polymers; ultrasonic absorption in polymethylmethacrylate; radiation damage in thin sheet fiberglass; epoxide resins; dynamic mechanical properties of poly (methacrylates); dielectric loss due to antioxidants in polyolefins; fracture measurements on polyethylene in comparison with epoxy resins; fatigue testing of epoxide resins; lap testing of epoxide resins; thermal conductivity and thermal expansion of non-metallic composite materials; nonlinear stresses and displacements of the fibers and matrix in a radially loaded circular composite ring; the strain energy release rate of glass fiber-reinforced polyester composites; charpy impact testing of cloth reinforced epoxide resin; nonmetallic and composite materials as solid superleaks; carbon fiber reinforced expoxide resins; standardizing nonmetallic composite materials.

  20. DOE/MSU composite material fatigue database: Test methods, materials, and analysis

    SciTech Connect

    Mandell, J.F.; Samborsky, D.D. [Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering

    1997-12-01

    This report presents a detailed analysis of the results from fatigue studies of wind turbine blade composite materials carried out at Montana State University (MSU) over the last seven years. It is intended to be used in conjunction with the DOE/MSU composite Materials Fatigue Database. The fatigue testing of composite materials requires the adaptation of standard test methods to the particular composite structure of concern. The stranded fabric E-glass reinforcement used by many blade manufacturers has required the development of several test modifications to obtain valid test data for materials with particular reinforcement details, over the required range of tensile and compressive loadings. Additionally, a novel testing approach to high frequency (100 Hz) testing for high cycle fatigue using minicoupons has been developed and validated. The database for standard coupon tests now includes over 4,100 data points for over 110 materials systems. The report analyzes the database for trends and transitions in static and fatigue behavior with various materials parameters. Parameters explored are reinforcement fabric architecture, fiber content, content of fibers oriented in the load direction, matrix material, and loading parameters (tension, compression, and reversed loading). Significant transitions from good fatigue resistance to poor fatigue resistance are evident in the range of materials currently used in many blades. A preliminary evaluation of knockdowns for selected structural details is also presented. The high frequency database provides a significant set of data for various loading conditions in the longitudinal and transverse directions of unidirectional composites out to 10{sup 8} cycles. The results are expressed in stress and strain based Goodman Diagrams suitable for design. A discussion is provided to guide the user of the database in its application to blade design.

  1. Content, format, gender and grade level differences in elementary students' ability to read science materials as measured by the cloze procedure

    NASA Astrophysics Data System (ADS)

    Williams, Richard L.; Yore, Larry D.

    Present instructional trends in science indicate a need to reexamine a traditional concern in science education: the readability of science textbooks. An area of reading research not well documented is the effect of color, visuals, and page layout on readability of science materials. Using the cloze readability method, the present study explored the relationships between page format, grade level, sex, content, and elementary school students ability to read science material. Significant relationships were found between cloze scores and both grade level and content, and there was a significant interaction effect between grade and sex in favor of older males. No significant relationships could be attributed to page format and sex. In the area of science content, biological materials were most difficult in terms of readability followed by earth science and physical science. Grade level data indicated that grade five materials were more difficult for that level than either grade four or grade six materials were for students at each respective level. In eight of nine cases, the science text materials would be classified at or near the frustration level of readability. The implications for textbook writers and publishers are that science reading materials need to be produced with greater attention to readability and known design principles regarding visual supplements. The implication for teachers is that students need direct instruction in using visual materials to increase their learning from text material. Present visual materials appear to neither help nor hinder the student to gain information from text material.

  2. Chemical microsensors based on polymer fiber composites

    NASA Astrophysics Data System (ADS)

    Kessick, Royal F.; Levit, Natalia; Tepper, Gary C.

    2005-05-01

    There is an urgent need for new chemical sensors for defense and security applications. In particular, sensors are required that can provide higher sensitivity and faster response in the field than existing baseline technologies. We have been developing a new solid-state chemical sensor technology based on microscale polymer composite fiber arrays. The fibers consist of an insulating polymer doped with conducting particles and are electrospun directly onto the surface of an interdigitated microelectrode. The concentration of the conducting particles within the fiber is controlled and is near the percolation threshold. Thus, the electrical resistance of the polymer fiber composite is very sensitive to volumetric changes produced in the polymer by vapor absorption. Preliminary results are presented on the fabrication and testing of the new microsensor. The objective is to take advantage of the very high surface to volume ratio, low thermal mass and linear geometry of the composite fibers to produce sensors exhibiting an extremely high vapor sensitivity and rapid response. The simplicity and low cost of a resistance-based chemical microsensor makes this sensing approach an attractive alternative to devices requiring RF electronics or time-of-flight analysis. Potential applications of this technology include battlespace awareness, homeland security, environmental surveillance, medical diagnostics and food process monitoring.

  3. Non-destructive prediction of chemical composition in sunflower seeds by near infrared spectroscopy

    Microsoft Academic Search

    A. Fassio; D. Cozzolino

    2004-01-01

    Near infrared reflectance spectroscopy (NIRS) was explored as a technique to predict moisture (M), oil and crude protein (CP) content on intact sunflower seeds (Helianthus annuus L.). Three hundred samples were scanned intact in a monochromator instrument NIRS 6500 (NIRSystems, Silver Spring, MD, USA). Calibration equations were developed using modified partial least square regression (MPLS) with internal cross validation. Samples

  4. Chemical imaging of biological materials by NanoSIMS using isotopic and elemental labels

    SciTech Connect

    Weber, P K; Fallon, S J; Pett-Ridge, J; Ghosal, S; Hutcheon, I D

    2006-04-10

    The NanoSIMS 50 combines unprecedented spatial resolution (as good as 50 nm) with ultra-high sensitivity (minimum detection limit of {approx}200 atoms). The NanoSIMS 50 incorporates an array of detectors, enabling simultaneous collection of 5 species originating from the same sputtered volume of a sample. The primary ion beam (Cs{sup +} or O{sup -}) can be scanned across the sample to produce quantitative secondary ion images. This capability for multiple isotope imaging with high spatial resolution provides a novel new approach to the study of biological materials. Studies can be made of sub-regions of tissues, mammalian cells, and bacteria. Major, minor and trace element distributions can be mapped on a submicron scale, growth and metabolism can be tracked using stable isotope labels, and biogenic origin can be determined based on composition. We have applied this technique extensively to mammalian and prokaryotic cells and bacterial spores. The NanoSIMS technology enables the researcher to interrogate the fate of molecules of interest within cells and organs through elemental and isotopic labeling. Biological applications at LLNL will be discussed.

  5. Measurement of nonlinear optical refraction of composite material based on sapphire with silver by Kerr-lens autocorrelation method.

    PubMed

    Yu, Xiang-xiang; Wang, Yu-hua

    2014-01-13

    Silver nanoparticles synthesized in a synthetic sapphire matrix were fabricated by ion implantation using the metal vapor vacuum arc ion source. The optical absorption spectrum of the Ag: Al2O3 composite material has been measured. The analysis of the supercontinuum spectrum displayed the nonlinear refractive property of this kind of sample. Nonlinear optical refraction index was identified at 800 nm excitation using the Kerr-lens autocorrelation (KLAC) technique. The spectrum showed that the material possessed self-defocusing property (n(2) = -1.1 × 10(-15) cm(2)W). The mechanism of nonlinear refraction has been discussed. PMID:24514979

  6. Certification of the reference material of water content in water saturated 1-octanol by Karl Fischer coulometry, Karl Fischer volumetry and quantitative nuclear magnetic resonance.

    PubMed

    Wang, Haifeng; Ma, Kang; Zhang, Wei; Li, Jia; Sun, Guohua; Li, Hongmei

    2012-10-15

    Certified reference materials (CRMs) of water content are widely used in the calibration and validation of Karl Fischer coulometry and volumetry. In this study, the water content of the water saturated 1-octanol (WSO) CRM was certified by Karl Fischer coulometry, volumetry and quantitative nuclear magnetic resonance (Q NMR). The water content recovery by coulometry was 99.76% with a diaphragm-less electrode and Coulomat AG anolyte. The relative bias between the coulometry and volumetry results was 0.06%. In Q NMR, the water content of WSO is traceable to the International System (SI) of units through the purity of internal standard. The relative bias of water content in WSO between Q NMR and volumetry was 0.50%. The consistency of results for these three independent methods improves the accuracy of the certification of the RM. The certified water content of the WSO CRM was 4.76% with an expanded uncertainty of 0.09%. PMID:23442697

  7. Designing high hard block Content TPU resins for composite application

    NASA Astrophysics Data System (ADS)

    Saiani, Alberto; Nedolisa, Chinemelum; Lindsay, Christopher; Polymer and Pepties Research Group Team; Huntsman Polyurethanes Team

    2013-03-01

    Thermoplastic Polyurethanes (TPU) are linear block copolymers typically constructed of statistically alternating soft (SS) and hard (HS) segments. Due to their numerous industrial applications these materials have received considerable attention. We have recently investigated the phase behavior and morphology of a set of high hard block content polyurethanes. Using mainly calorimetry, scattering and microscopy techniques we were able to elucidate the origins of all the thermal events observed through differential scanning calorimetry and propose a new morphological model of the structure and the phase behavior of these high hard block content polyurethanes [A. Saiani et al. Macromolecules, 34, 9059-9068 (2001); 37, 1411-1421 (2004); 40, 7252-7262 (2007)]. We have now shown that these new materials can potentially be used as resins for designing fiber based composites and investigated the effect of processing on conditions the final properties of the composites

  8. Carbon Nano Tube Composites with Chemically Functionalized Plant Oils

    Microsoft Academic Search

    Wim Thielemans; Richard P. Wool; Werner Blau; Valerie Barron

    2003-01-01

    Carbon Nano Tube Composites with Chemically Functionalized Plant Oil Wim Thielemans, R., P. Wool, V. Barron and W. Blau Multi-Wall Carbon Nano Tubes (MWCNT) made by the Kratchmer-Huffman CCVD process were found to interact and solubilize by slow mechanical stirring, with chemically functionalized plant oils, such as acrylated, epoxidized and maleinated triglycerides (TG) derived from plant oils. The chemical functionality

  9. Colorimetric evaluation of composite materials with different thickness by reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Portero, Priscila Paiva; Florez, Fernando; Bagnato, Vanderlei; de Oliveira, Osmir Batista, Jr.; de Castro Monteiro Loffredo, Leonor

    2007-02-01

    Selection of the proper shade and color matching of restorations to natural dentition continues to be one of the most frustrating problems in dentistry and currently available shade guide presents a limited selection of colors compared to those found in natural dentition. This investigation evaluation if the composites resins shade B2 are equivalent to the Vita shade guide B2. Twelve composite resins (Renamel Microfill Super Brite- Cosmedent USA, Renamel Universal Brite- Cosmedent USA, Renamel Microfill Body- Cosmedent USA, Renamel Universal Body- Cosmedent USA, Opallis EB2-FGM, Opallis DB2-FGM, Filtek Supreme XT-3M/ESPE, Filtek Z250-3M/ESPE, Filtek Z350-3M/ESPE, Z100-3M/ESPE, 4 Seasons Dentin-Ivoclar/Vivadent, Tetric Ceram-Ivoclar/Vivadent) shade B2 were used. From each composite, two specimens were made in a steel matrix with 8.0 mm diameter and 10.0 mm different predetermined thickness (0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0 mm). The specimens were 40 seconds light polymerized by LED Ultrablue (DMC). The specimens were measured 10 times each to determine the shade using a reflectance spectrophotometer (Pocket Spec). According to results was verified that not any of composites resins shade B2 evaluated in this study presented values of color difference (?E) equivalent to the Vita shade guide B2 and the 2 mm thickness showed the closer match to the Vita shade guide B2.

  10. Aeroelastic tailoring of composite materials 

    E-print Network

    Rogers, Jesse Byron

    1979-01-01

    LIST OF FIGURES IiiTRODUCTI ON ST!!UCTURAL RESPONSE Deformation of Uniformly Stressed Isotropic and Anisotropic Plates Characterization of Composite Laminates . Effect of Material Parameters APPLICATIONS Aircraft Propellers Ship Propell rs... com- pliances with laminate rotation 39 15 Variation of (A) extensional ard (8) bending compliances with 0' ply rotation . . . . . . . . . . . . . . . . 40 16 Incremental aerodynamic forces on a typical blade element 43 17 Propeller velocity...

  11. Organizing Behaviors that Facilitate Comprehension in Content Materials.

    ERIC Educational Resources Information Center

    Carney, John J.

    Teachers can help students develop effective content reading/study skills by manipulating the presentation of reading materials in such a way that students can see and internalize model behaviors associated with those skills. For example, teachers can augment paragraphs of content materials with short exercises in using context clues to infer the…

  12. Modification of seed oil content and acyl composition in the brassicaceae by expression of a yeast sn-2 acyltransferase gene.

    PubMed Central

    Zou, J; Katavic, V; Giblin, E M; Barton, D L; MacKenzie, S L; Keller, W A; Hu, X; Taylor, D C

    1997-01-01

    A putative yeast sn-2 acyltransferase gene (SLC1-1), reportedly a variant acyltransferase that suppresses a genetic defect in sphingolipid long-chain base biosynthesis, has been expressed in a yeast SLC deletion strain. The SLC1-1 gene product was shown in vitro to encode an sn-2 acyltransferase capable of acylating sn-1 oleoyl-lysophosphatidic acid, using a range of acyl-CoA thioesters, including 18:1-, 22:1-, and 24:0-CoAs. The SLC1-1 gene was introduced into Arabidopsis and a high erucic acid-containing Brassica napus cv Hero under the control of a constitutive (tandem cauliflower mosaic virus 35S) promoter. The resulting transgenic plants showed substantial increases of 8 to 48% in seed oil content (expressed on the basis of seed dry weight) and increases in both overall proportions and amounts of very-long-chain fatty acids in seed triacylglycerols (TAGs). Furthermore, the proportion of very-long-chain fatty acids found at the sn-2 position of TAGs was increased, and homogenates prepared from developing seeds of transformed plants exhibited elevated lysophosphatidic acid acyltransferase (EC 2.3.1.51) activity. Thus, the yeast sn-2 acyltransferase has been shown to encode a protein that can exhibit lysophosphatidic acid acyltransferase activity and that can be used to change total fatty acid content and composition as well as to alter the stereospecific acyl distribution of fatty acids in seed TAGs. PMID:9212466

  13. Modification of seed oil content and acyl composition in the brassicaceae by expression of a yeast sn-2 acyltransferase gene.

    PubMed

    Zou, J; Katavic, V; Giblin, E M; Barton, D L; MacKenzie, S L; Keller, W A; Hu, X; Taylor, D C

    1997-06-01

    A putative yeast sn-2 acyltransferase gene (SLC1-1), reportedly a variant acyltransferase that suppresses a genetic defect in sphingolipid long-chain base biosynthesis, has been expressed in a yeast SLC deletion strain. The SLC1-1 gene product was shown in vitro to encode an sn-2 acyltransferase capable of acylating sn-1 oleoyl-lysophosphatidic acid, using a range of acyl-CoA thioesters, including 18:1-, 22:1-, and 24:0-CoAs. The SLC1-1 gene was introduced into Arabidopsis and a high erucic acid-containing Brassica napus cv Hero under the control of a constitutive (tandem cauliflower mosaic virus 35S) promoter. The resulting transgenic plants showed substantial increases of 8 to 48% in seed oil content (expressed on the basis of seed dry weight) and increases in both overall proportions and amounts of very-long-chain fatty acids in seed triacylglycerols (TAGs). Furthermore, the proportion of very-long-chain fatty acids found at the sn-2 position of TAGs was increased, and homogenates prepared from developing seeds of transformed plants exhibited elevated lysophosphatidic acid acyltransferase (EC 2.3.1.51) activity. Thus, the yeast sn-2 acyltransferase has been shown to encode a protein that can exhibit lysophosphatidic acid acyltransferase activity and that can be used to change total fatty acid content and composition as well as to alter the stereospecific acyl distribution of fatty acids in seed TAGs. PMID:9212466

  14. Bacterial Community Composition in the Gut Content and Ambient Sediment of Sea Cucumber Apostichopus japonicus Revealed by 16S rRNA Gene Pyrosequencing

    PubMed Central

    Gao, Fei; Li, Fenghui; Tan, Jie; Yan, Jingping; Sun, Huiling

    2014-01-01

    The composition of the bacterial communities in the contents of the foregut and hindgut of the sea cucumber Apostichopus japonicus and in the ambient surface sediment was surveyed by 16S rRNA gene 454-pyrosequencing. A total of 188,623 optimized reads and 15,527 operational taxonomic units (OTUs) were obtained from the ten gut contents samples and four surface sediment samples. The sequences in the sediments, foregut contents, and hindgut contents were assigned to 38.0±4.7, 31.2±6.2 and 27.8±6.5 phyla, respectively. The bacterial richness and Shannon diversity index were both higher in the ambient sediments than in the gut contents. Proteobacteria was the predominant phylum in both the gut contents and sediment samples. The predominant classes in the foregut, hindgut, and ambient sediment were Holophagae and Gammaproteobacteria, Deltaproteobacteria and Gammaproteobacteria, and Gammaproteobacteria and Deltaproteobacteria, respectively. The potential probiotics, including sequences related to Bacillus, lactic acid bacteria (Lactobacillus, Lactococcus, and Streptococcus) and Pseudomonas were detected in the gut of A. japonicus. Principle component analysis and heatmap figure showed that the foregut, hindgut, and ambient sediment respectively harbored different characteristic bacterial communities. Selective feeding of A. japonicus may be the primary source of the different bacterial communities between the foregut contents and ambient sediments. PMID:24967593

  15. Determination of seed oil content and fatty acid composition in sunflower through the analysis of intact seeds, husked seeds, meal and oil by near-infrared reflectance spectroscopy

    Microsoft Academic Search

    B. Pérez-Vich; L. Velasco; J. M. Fernández-Martínez

    1998-01-01

    A methodological study was conducted to test the potential of near-infrared reflectance spectroscopy (NIRS) to estimate the\\u000a oil content and fatty acid composition of sunflower seeds. A set of 387 intact-seed samples, each from a single plant, were\\u000a scanned by NIRS, and 120 of them were selected and further scanned as husked seed, meal, and oil. All samples were analyzed

  16. Estimation of seed weight, oil content and fatty acid composition in intact single seeds of rapeseed ( Brassica napus} L.) by near-infrared reflectance spectroscopy

    Microsoft Academic Search

    Leonardo Velasco; Christian Möllers; Heiko C. Becker

    1999-01-01

    The potential of near-infrared reflectance spectroscopy (NIRS) for the simultaneous analysis of seed weight, total oil content\\u000a and its fatty acid composition in intact single seeds of rapeseed was studied. A calibration set of 530 single seeds was analysed\\u000a by both NIRS and gas-liquid chromatography (GLC) and calibration equations for the major fatty acids were developed. External\\u000a validation with a

  17. Property changes induced by the space environment in composite materials on LDEF: Solar array materials passive LDEF experiment A0171 (SAMPLE)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Surface modifications to composite materials induced by long term exposure in low earth orbit (LEO) were dominated by atomic oxygen erosion and micrometeoroid and space debris impacts. As expected, calculated erosion rates were peculiar to material type and within the predicted order of magnitude. Generally, about one ply of the carbon fiber composites was eroded during the 70 month LDEF experiment. Matrix erosion was greater than fiber erosion and was more evident for a polysulfone matrix than for epoxy matrices. Micrometeoroid and space debris impacts resulted in small (less than 1mm) craters and splattered contaminants on all samples. Surfaces became more diffuse and darker with small increases in emissivity and absorption. Tensile strength decreased roughly with thickness loss, and epoxy matrices apparently became slightly embrittled, probably as a result of continued curing under UV and/or electron bombardment. However, changes in the ultimate yield stress of the carbon reinforced epoxy composites correlate neither with weave direction nor fiber type. Unexpected developments were the discovery of new synergistic effects of the space environment in the interaction of atomic oxygen and copious amounts of contamination and in the induced luminescence of many materials.

  18. Turbostratic boron carbonitride films produced by bias-assisted hot filament chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Yu, J.; Wang, E. G.; Ahn, J.; Yoon, S. F.; Zhang, Q.; Cui, J.; Yu, M. B.

    2000-04-01

    Boron carbonitride (BCN) films with various compositions have been prepared by bias-assisted hot filament chemical vapor deposition. The three elements of B, C, and N are chemically bonded with each other and an atomic-level BCN hybrid has been formed in the films. The deposited films are composed of turbostratic structural regions ranging from a few to a few tens of nanometers. Besides, there exist some amorphous domains in the films. Boron atoms have been confirmed to be incorporated into the films with a concentration up to 70 at. %. The interplanar spacing of 3.49 Å is found to be independent of the film composition in this range. These films show a blueshift in photoluminescence peak with increasing B content. These findings show that the electronic structure of BCN compounds can be controlled by changing compositions and the BCN compounds are blue-light emitting materials.

  19. Influence of anionic monomer content on the biodegradation and toxicity of polyvinyl-urethane carbonate-ceramic interpenetrating phase composites.

    PubMed

    Yang, Liu; Hong, Jason; Wang, Jian; Pilliar, Robert M; Santerre, J Paul

    2005-10-01

    The objective of this study was to characterize a series of anionic biodegradable polymer resins for their compatibility in a biological environment, comparing them with respect to the influence of ionic function on enzyme catalyzed biodegradation when the polymers were incorporated into a porous calcium polyphosphate (CPP) 3-D structure to form an interpenetrating phase composite (IPC). The swelling behavior of the polymers was investigated by immersing the cured polymer resins in growth media at 37 degrees C. In vitro cytotoxicity of the polymer resins was assessed using a HeLa cell line. Cell viability increased when the amount of low molecular weight monomer was minimized. Despite observing that the addition of carboxylic acid groups into the polymer resin chains contributed to an improvement of the chemical bonding between the polymer and the CPP, the addition of high ionic content into the resin led to the greatest loss of bending strength for the samples incubated in phosphate buffer and cholesterol esterase enzyme solutions, when compared to their as made state. The increased degradation for the higher ionic component materials and their loss of physical strength was attributed to enhanced hydrolysis within the materials and by water transport deep within the composites, via the anionic components of the resin. The findings indicated that the introduction of anionic content must be optimized to promote increased mechanical performance for the CPP, balancing the features of polymer CPP bonding versus polymer swelling and cytotoxicity. PMID:15958241

  20. Contraction Measurements of Dental Composite Material during Photopolymerization by a Fiber Optic Interferometric Method.

    NASA Astrophysics Data System (ADS)

    Arenas, Gustavo; Noriega, Sergio; Mucci, Veronica; Vallo, Claudia; Duchowicz, Ricardo

    2008-04-01

    In order to monitor the shrinkage generated by new composites during photopolymerization, we have implemented a fiber optic sensing method based on a Fizeau-type interferometric scheme. This simple, compact, non-invasive and self-calibrating system competes with both conventional and other high-resolution bulk interferometric techniques. Several stages of the curing process were characterized from sample interferograms, including photopolymerization inhibition, the onset and degree of sample shrinkage, as well as typical kinetic behaviour of photopolymerization of dimethacrylates monomers. Some complementary studies (temperature and transmission measurements) were performed to complete the kinetic scheme. A simple polymerization model was generated in order to discuss the main results.

  1. INTERNATIONAL CONFERENCE ON COMPOSITE MATERIALS 1 Introduction

    E-print Network

    Boyer, Edmond

    are injected by a low viscosity resin. During this process, we have to pay particular attention to the void materials can be elaborated by Liquid Composite Molding (LCM), a family of processes where fibrous preforms flow rates. Liquid is injected in the T- shaped junction by two syringe compressors in setting two

  2. Novel Microstructures for Polymer-Liquid Crystal Composite Materials

    NASA Technical Reports Server (NTRS)

    Magda, Jules J.

    2004-01-01

    There are a number of interface-dominated composite materials that contain a liquid crystalline (LC) phase in intimate contact with an isotropic phase. For example, polymer- dispersed liquid crystals, used in the fabrication of windows with switchable transparency, consist of micron size LC droplets dispersed in an isotropic polymer matrix. Many other types of liquid crystal composite materials can be envisioned that might have outstanding optical properties that could be exploited in novel chemical sensors, optical switches, and computer displays. This research project was based on the premise that many of these potentially useful LC composite materials can only be fabricated under microgravity conditions where gravity driven flows are absent. In the ground-based research described below, we have focused on a new class of LC composites that we call thermotropic- lyotropic liquid crystal systems (TLLCs). TLLCs consist of nanosize droplets of water dispersed in an LC matrix, with surfactants at the interface that stabilize the structure. By varying the type of surfactant one can access almost an infinite variety of unusual LC composite microstructures. Due to the importance of the interface in these types of systems, we have also developed molecular simulation models for liquid crystals at interfaces, and made some of the first measurements of the interfacial tension between liquid crystals and water.

  3. Pyrolysis of municipal plastic wastes II: Influence of raw material composition under catalytic conditions

    SciTech Connect

    Lopez, A., E-mail: alex.lopez@ehu.es [Chemical and Environmental Engineering Department, School of Engineering of Bilbao, Alda. Urquijo s/n, 48013 Bilbao (Spain); Marco, I. de; Caballero, B.M.; Laresgoiti, M.F.; Adrados, A.; Torres, A. [Chemical and Environmental Engineering Department, School of Engineering of Bilbao, Alda. Urquijo s/n, 48013 Bilbao (Spain)

    2011-09-15

    Highlights: > ZSM-5 zeolite catalytic pyrolysis transforms municipal plastic waste into liquids and gases useful as fuels or source of chemicals. > The composition of the waste sample plays an important role on the catalyst activity and the products obtained. > ZSM-5 zeolite is somehow deactivated when high proportions of fine inorganic materials are present in the sample. > When the sample contains cellulose-based materials, the formation of a two-phase liquid fraction can be avoided by a low temperature step. - Abstract: In this work, the results obtained in catalytic pyrolysis of three plastic waste streams which are the rejects of an industrial packing wastes sorting plant are presented. The samples have been pyrolysed in a 3.5 dm{sup 3} reactor under semi-batch conditions at 440 {sup o}C for 30 min in nitrogen atmosphere. Commercial ZSM-5 zeolite has been used as catalyst in liquid phase contact. In every case, high HHV gases and liquids which can be useful as fuels or source of chemicals are obtained. A solid fraction composed of the inorganic material contained in the raw materials and some char formed in the pyrolysis process is also obtained. The zeolite has shown to be very effective to produce liquids with great aromatics content and C3-C4 fraction rich gases, even though the raw material was mainly composed of polyolefins. The characteristics of the pyrolysis products as well as the effect of the catalyst vary depending on the composition of the raw material. When paper rich samples are pyrolysed, ZSM-5 zeolite increases water production and reduces CO and CO{sub 2} generation. If stepwise pyrolysis is applied to such sample, the aqueous liquid phase can be separated from the organic liquid fraction in a first low temperature step.

  4. Properties of composite materials for cryogenic applications

    Microsoft Academic Search

    J. B Schutz

    1998-01-01

    Composite materials are used in a wide variety of cryogenic applications because of their unique and highly tailorable properties. These cryogenic applications of composites may be, for the sake of discussion, classified as support structures, vessels, or electrical insulation. Examples of these applications are presented, with a brief discussion of the critical material properties associated with each application. Composite material

  5. ULTRASONIC CHARACTERIZATION OF ADVANCED COMPOSITE MATERIALS

    Microsoft Academic Search

    B. Boro Djordjevic

    With increased use of composite materials in critical structural applications it is more important than ever to independently assure structural integrity. Complexity of the advanced composite materials including layered and bonded structures represents challenges in developing optimized ultrasonic tests. Traditional ultrasonic NDT methods are inappropriate and often misleading when applied to anisotropic and nonhomogeneous composite materials. In advanced technology applications

  6. Nonintrusive interfacial characterization of advanced composite materials

    Microsoft Academic Search

    Renee M. Kent

    1995-01-01

    It is well known that the fiber matrix interface plays the dominant role in the mechanical behavior of advanced composite materials. Engineering and control of the interface is paramount to producing the properties for desired mechanical performance of the ultimate composite structure. This is particularly critical for advanced composites (metal matrix composites, ceramic matrix composites) which are currently being investigated

  7. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Ogawa, Fumio; Masuda, Chitoshi

    2015-01-01

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites.

  8. Branch Content in Hybrid Materials using Small-Angle Scattering

    NASA Astrophysics Data System (ADS)

    Beaucage, Greg

    2005-03-01

    Inorganic/organic hybrid materials often display ramified mass- fractal structures characterized by primary particle size, aggregate size, and mass-fractal dimension. Physical properties, such as mechanical and dynamic mechanical properties and electrical conductivity (in carbon composites for instance), can not be predicted using only these structural features since such properties are intimately tied to the degree and type of branching as shown by Witten [1]. Witten suggested the use of the minimum dimension, or the related connectivity dimension, to calculate mechanical response in these hybrid systems. A viable technique to quantify the minimum dimension and connectivity dimension in hybrid materials has, until recently, been absent from the literature. This presentation will discuss the use of small-angle x-ray and neutron scattering to describe branch content in hybrid materials [2] and will outline an approach to use the minimum dimension and connectivity dimension to predict static and dynamic mechanical properties for hybrid materials based on structure [1, 3]. 1. Witten TA, Rubinstein M, Colby RH Reinforcement of Rubber by Fractal Aggregates J Phys II 3 (3): 367-383 (1993). 2. Beaucage G Determination of branch fraction and minimum dimension of mass-fractal aggregates Phys Rev E 70 (3): art. no. 031401 Part 1 (2004). 3. Kohls DJ, Beaucage G Rational design of reinforced rubber Curr Opin Solid St M 6 (3): 183-194 (2002).

  9. Profiling the Triacylglyceride Contents in Bat Integumentary Lipids by Preparative Thin Layer Chromatography and MALDI-TOF Mass Spectrometry

    PubMed Central

    Pannkuk, Evan L.; Risch, Thomas S.; Savary, Brett J.

    2013-01-01

    The mammalian integument includes sebaceous glands that secrete an oily material onto the skin surface. Sebum production is part of the innate immune system that is protective against pathogenic microbes. Abnormal sebum production and chemical composition are also a clinical symptom of specific skin diseases. Sebum contains a complex mixture of lipids, including triacylglycerides, which is species-specific. The broad chemical properties exhibited by diverse lipid classes hinder the specific determination of sebum composition. Analytical techniques for lipids typically require chemical derivatizations that are labor-intensive and increase sample preparation costs. This paper describes how to extract lipids from mammalian integument, separate broad lipid classes by thin-layer chromatography, and profile the triacylglyceride contents using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This robust method enables a direct determination of the triacylglyceride profiles among species and individuals, and it can be readily applied to any taxonomic group of mammals. PMID:24056580

  10. Chemical provinces reveal Elysium Volcano's compositional evolution

    NASA Astrophysics Data System (ADS)

    Susko, D. A.; Karunatillake, S.; Wray, J. J.; Skok, J. R.; Hurowitz, J.; Ojha, L.; Judice, T.; Bently, R. O. J.

    2014-12-01

    Chemical provinces of Mars became definable[1-3] with the maps of elemental mass fractions generated with Mars Odyssey Gamma Ray Spectrometer (GRS) data[4,5]. Previous work highlighted the Elysium lava flow province as anomalous, with a depletion in K and Th relative to the average crust in the rest of Mars (ROM).[3] We characterize the elemental composition, geology, and geomorphology of the region to constrain the processes that have contributed to its evolution. We compare SE Elysium with its North West lava fields, advancing prior work on thermal evolution of the martian mantle.[6] Lava fields at both sites probably source from Elysium eruptions. Both show similar Si content, as well as a Ca-enrichment compared to ROM, consistent with prior models.[6,7] Nevertheless, the two fields are compositionally distinct from each other, with NW Elysium decisively depleted in Ca and Fe, but enriched in K and Th. Such distinctness, in elements that reflect magmatic fractionation, reveals the possibility that a single volcanic complex on Mars may evolve rapidly during the Amazonian era, causing variable flow compositions. Interestingly, a chemical province containing volcanics that is contemporaneous with Elysium, overlaps the Tharsis region.[3] Unlike Elysium, the K and Th distributions within Tharsis are indistinguishable from ROM. Meanwhile, the mass fraction signature in Tharsis is enriched in Cl and depleted in Si. Such contrast, in chemical anomalies between volcanic constructs of similar age, may indicate that the depletion of K and Th in SE Elysium did not arise from temporal evolution of the mantle. [1] Taylor, G. et al. Geology 38, 183-186, 2010 [2] Gasnault, O. et al. 207, 226-247, 2010 [3] Karunatillake, S. et al. J. Geophys. Res. 114, E12001, 2009 [4] Boynton, W. V. et al. J. Geophys. Res. 112, E12S99, 2007 [5] Feldman, W. C. et al. J. Geophys. Res. 109, E09006, 2004 [6] Baratoux, D. et al. Nature 472, 338-41, 2011 [7] Balta, J. et al. Geology 41, 1115-1118, 2013

  11. Surface Chemical Composition of Size-fractionated Urban Walkway Aerosols Determined by XPS and ToF-SIMS

    NASA Astrophysics Data System (ADS)

    Wenjuan, Cheng; Lu-Tao, Weng; Yongjie, Li; Arthur, Lau; Chak, Chan; Chi-Ming, Chan

    2013-04-01

    In this study, aerosol particles with sizes ranging from 0.056 to 10 ?m were collected using a ten-stage impactor sampler (MOUDI) from a busy walkway of Hong Kong. The aerosol samples of each stage were examined with X-ray photoelectron spectroscopy (XPS). Size dependent distributions of the detected six key elements (N, S, Ca, Si, O, and C) were revealed together with the chemical states of N, S and C. The results indicated that aliphatic hydrocarbons were the dominant species on the surface of all particles while a small portion of graphitic carbon (due to elemental and aromatic hydrocarbons) was also detected on the surface of the particles with sizes ranging from 0.056 to 0.32 ?m. Organic oxygen- and nitrogen-containing surface groups as well as sulfates were more abundant on the surface of the particles with sizes ranging from 0.32 to 1 ?m. Organic oxygen- and nitrogen-containing surface groups as well as sulfates were more abundant on the surface of the particles with sizes ranging from 0.32 to 1 ?m. Inorganic salts and nitrates were found in coarse-mode particles. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used for detailed surface and near surface composition analysis. Principal component analysis (PCA) of the ToF-SIMS spectra confirmed the XPS results that aromatic hydrocarbons were associated with the nucleation-mode particles. Aliphatic hydrocarbons with O- and N-containing functional groups were associated with accumulation-mode particles and inorganic salts were related to the coarse-mode particles. Depth-profiling experiments were performed on three specific sets of samples (nucleation-, accumulation- and coarse-mode particles) to study their near-surface structures. It showed that organic compounds were concentrated on the very top surface of the coarse-mode particles with inorganics in the core. The accumulation-mode particles had thick coatings of diverse organic compositions. The nucleation-mode particles, which contained graphitic carbon in the core, were partially coated with aliphatic/aromatic hydrocarbons on the surface. This study confirms that the surface chemical compositions of aerosols were size dependent and quite different among the particles of the three modes. Key words: size-segregated, aerosol particles, surface properties, XPS, ToF-SIMS Acknowledgement This work was fully supported by a UGC-Infrastructure Grant # SBI11IPO01

  12. Plastic working of laminated composite materials

    Microsoft Academic Search

    S. V. Voronov; D. G. Devoino

    1982-01-01

    Plastic working can be successfully employed for increasing the strength of the joint in a laminated composite material whose components react with each other during high-speed cladding, with the formation of brittle intermetallic compouds. At the same time, by suitable choice of reduction and mismatch, it is possible to produce straight bimetallic strips by rolling them with mismatched peripheral roll

  13. Comparison of sodium content of workplace and homemade meals through chemical analysis and salinity measurements

    PubMed Central

    Shin, Eun-Kyung

    2014-01-01

    BACKGROUND/OBJECTIVES Most Koreans consume nearly 70-80% of the total sodium through their dishes. The use of a salinometer to measure salinity is recommended to help individuals control their sodium intake. The purpose of this study was to compare sodium content through chemical analysis and salinity measurement in foods served by industry foodservice operations and homemade meals. MATERIALS/METHODS Workplace and homemade meals consumed by employees in 15 cafeterias located in 8 districts in Daegu were collected and the sodium content was measured through chemical analysis and salinity measurements and then compared. The foods were categorized into 9 types of menus with 103 workplace meals and 337 homemade meals. RESULTS Workplace meals did not differ significantly in terms of sodium content per 100 g of food but had higher sodium content via chemical analysis in roasted foods per portion. Homemade meals had higher broth salt content and higher salt content by chemical analysis per 100 g of roasted foods and hard-boiled foods. One-dish workplace meals had higher salinity (P < 0.05), while homemade broths and stews had higher sodium content (P < 0.05 and P < 0.01, respectively). The sodium content per 100 g of foods was higher in one-dish workplace meals (P < 0.05) and in homemade broths and stews (P < 0.01 and P < 0.05, respectively). CONCLUSIONS The use of a salinometer may be recommended to estimate the sodium content in foods and control one's sodium intake within the daily intake target as a way to promote cooking bland foods at home. However, estimated and actual measured values may differ. PMID:25324937

  14. Hyphenation of Thermal Analysis to Ultrahigh-Resolution Mass Spectrometry (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry) Using Atmospheric Pressure Chemical Ionization For Studying Composition and Thermal Degradation of Complex Materials.

    PubMed

    Rüger, Christopher P; Miersch, Toni; Schwemer, Theo; Sklorz, Martin; Zimmermann, Ralf

    2015-07-01

    In this study, the hyphenation of a thermobalance to an ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometer (UHR FTICR MS) is presented. Atmospheric pressure chemical ionization (APCI) is used for efficient ionization. The evolved gas analysis (EGA), using high-resolution mass spectrometry allows the time-resolved molecular characterization of thermally induced processes in complex materials or mixtures, such as biomass or crude oil. The most crucial part of the setup is the hyphenation between the thermobalance and the APCI source. Evolved gases are forced to enter the atmospheric pressure ionization interface of the MS by applying a slight overpressure at the thermobalance side of the hyphenation. Using the FTICR exact mass data, detailed chemical information is gained by calculation of elemental compositions from the organic species, enabling a time and temperature resolved, highly selective detection of the evolved species. An additional selectivity is gained by the APCI ionization, which is particularly sensitive toward polar compounds. This selectivity on the one hand misses bulk components of petroleum samples such as alkanes and does not deliver a comprehensive view but on the other hand focuses particularly on typical evolved components from biomass samples. As proof of principle, the thermal behavior of different fossil fuels: heavy fuel oil, light fuel oil, and a crude oil, and different lignocellulosic biomass, namely, beech, birch, spruce, ash, oak, and pine as well as commercial available softwood and birch-bark pellets were investigated. The results clearly show the capability to distinguish between certain wood types through their molecular patterns and compound classes. Additionally, typical literature known pyrolysis biomass marker were confirmed by their elemental composition, such as coniferyl aldehyde (C10H10O3), sinapyl aldehyde (C11H12O4), retene (C18H18), and abietic acid (C20H30O2). PMID:26024433

  15. Chemical versus electrochemical synthesis of carbon nano-onion/polypyrrole composites for supercapacitor electrodes.

    PubMed

    Mykhailiv, Olena; Imierska, Monika; Petelczyc, Martyna; Echegoyen, Luis; Plonska-Brzezinska, Marta E

    2015-04-01

    The development of high-surface-area carbon electrodes with a defined pore size distribution and the incorporation of pseudo-active materials to optimize the overall capacitance and conductivity without destroying the stability are at present important research areas. Composite electrodes of carbon nano-onions (CNOs) and polypyrrole (Ppy) were fabricated to improve the specific capacitance of a supercapacitor. The carbon nanostructures were uniformly coated with Ppy by chemical polymerization or by electrochemical potentiostatic deposition to form homogenous composites or bilayers. The materials were characterized by transmission- and scanning electron microscopy, differential thermogravimetric analyses, FTIR spectroscopy, piezoelectric microgravimetry, and cyclic voltammetry. The composites show higher mechanical and electrochemical stabilities, with high specific capacitances of up to about 800?F?g(-1) for the CNOs/SDS/Ppy composites (chemical synthesis) and about 1300?F?g(-1) for the CNOs/Ppy bilayer (electrochemical deposition). PMID:25736714

  16. Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites

    SciTech Connect

    Anderl, Robert Andrew; Pawelko, Robert James; Smolik, Galen Richard

    2001-05-01

    This report documents experiments and analyses that have been done at the Idaho National Engineering and Environmental Laboratory (INEEL) to measure the steam chemical reactivity of two types of carbon fiber composites, NS31 and NB31, proposed for use at the divertor strike points in an ITER-like tokamak. These materials are 3D CFCs constituted by a NOVOLTEX preform and densified by pyrocarbon infiltration and heat treatment. NS31 differs from NB31 in that the final infiltration was done with liquid silicon to reduce the porosity and enhance the thermal conductivity of the CFC. Our approach in this work was twofold: (1) physical characterization measurements of the specimens and (2) measurements of the chemical reactivity of specimens exposed to steam.

  17. Bioinspired porous octacalcium phosphate/silk fibroin composite coating materials prepared by electrochemical deposition.

    PubMed

    Yang, Ya; Wang, Hui; Yan, Feng-Yi; Qi, Yu; Lai, Yue-Kun; Zeng, Dong-Mei; Chen, Guoqiang; Zhang, Ke-Qin

    2015-03-18

    The biomimetic structure and composition of biomaterials are recognized as critical factors that determine their biological performance. A bioinspired nano-micro structured octacalcium phosphate (OCP)/silk fibroin (SF) composite coating on titanium was achieved through a mild electrochemically induced deposition method. Findings indicate that SF plays a critical role in constructing the unique biomimetic hierarchical structure of OCP/SF composite coating layers. In vitro cell culture tests demonstrate that the presence of OCP/SF composite coatings, with highly ordered and hierarchically porous structure, greatly enhance cellular responses. The coatings developed in this study have considerable potential for various hard tissue engineering and applications. PMID:25734421

  18. A non-invasive XRF study supported by multivariate statistical analysis and reflectance FTIR to assess the composition of modern painting materials

    NASA Astrophysics Data System (ADS)

    Rosi, Francesca; Burnstock, Aviva; Van den Berg, Klaas Jan; Miliani, Costanza; Brunetti, Brunetto Giovanni; Sgamellotti, Antonio

    2009-01-01

    The palette used in two paintings by Paul Cézanne, L'étang des sœurs dated c. 1875 and La route tournante, made in the last year of his life (1902), were analyzed using non-invasive spectroscopic methods. X-ray fluorescence combined with principal components analysis (PCA) and supported by reflectance near- and mid-FTIR was shown to be a powerful analytical tool to draw conclusions about the chemical identification of inorganic materials in paintings. Pigments and fillers such us Thénard's blue, Prussian blue, red ochre, kaolin, vermilion, lead white, zinc white and barium sulphate, were identified. Evidence for three different pigments, namely a copper arsenite pigment, chrome green (a mixture of chrome yellow and Prussian blue) and viridian has been obtained by the PCA analysis of elemental compositions of green hues.

  19. Glasses, ceramics, and composites from lunar materials

    NASA Astrophysics Data System (ADS)

    Beall, George H.

    1992-02-01

    A variety of useful silicate materials can be synthesized from lunar rocks and soils. The simplest to manufacture are glasses and glass-ceramics. Glass fibers can be drawn from a variety of basaltic glasses. Glass articles formed from titania-rich basalts are capable of fine-grained internal crystallization, with resulting strength and abrasion resistance allowing their wide application in construction. Specialty glass-ceramics and fiber-reinforced composites would rely on chemical separation of magnesium silicates and aluminosilicates as well as oxides titania and alumina. Polycrystalline enstatite with induced lamellar twinning has high fracture toughness, while cordierite glass-ceramics combine excellent thermal shock resistance with high flexural strengths. If sapphire or rutile whiskers can be made, composites of even better mechanical properties are envisioned.

  20. Identification of lead chemical form in mine waste materials by X-ray absorption spectroscopy

    SciTech Connect

    Taga, Raijeli L.; Ng, Jack [University of Queensland, National Research Centre for Environmental Toxicology (EnTox), Brisbane, 4108 (Australia); Zheng Jiajia; Huynh, Trang; Noller, Barry [University of Queensland, Centre for Mined Land Rehabilitation, Brisbane, 4072 (Australia); Harris, Hugh H. [School of Chemistry and Physics, University of Adelaide, Adelaide, 5005 (Australia)

    2010-06-23

    X-ray absorption spectroscopy (XAS) provides a direct means for measuring lead chemical forms in complex samples. In this study, XAS was used to identify the presence of plumbojarosite (PbFe{sub 6}(SO{sub 4}){sub 4}(OH){sub 12}) by lead L{sub 3}-edge XANES spectra in mine waste from a small gold mining operation in Fiji. The presence of plumbojarosite in tailings was confirmed by XRD but XANES gave better resolution. The potential for human uptake of Pb from tailings was measured using a physiologically based extract test (PBET), an in-vitro bioaccessibility (BAc) method. The BAc of Pb was 55%. Particle size distribution of tailings indicated that 40% of PM{sub 10} particulates exist which could be a potential risk for respiratory effects via the inhalation route. Food items collected in the proximity of the mine site had lead concentrations which exceed food standard guidelines. Lead within the mining lease exceeded sediment guidelines. The results from this study are used to investigate exposure pathways via ingestion and inhalation for potential risk exposure pathways of Pb in that locality. The highest Pb concentration in soil and tailings was 25,839 mg/kg, exceeding the Australian National Environment Protection Measure (NEPM) soil health investigation levels.

  1. Some strength properties of graphite-zirconium carbide composite materials

    Microsoft Academic Search

    V. S. Dergunova; A. N. Shurshakov; G. D. Posos'eva; L. N. Lutsenko

    1972-01-01

    1.Some factors influencing the strength of composite materials were examined.2.A study was made of the strength properties of graphite-zirconium carbide and graphite-zirconium carbide-zirconium composite materials having varying structures and compositions. It was found that, at 2500‡C, the tensile strength of TsG-25 type composite material is 30% higher than that of dense VPP constructional graphite.3.It was established that, by varying the

  2. Early Fatigue Damage Detection in Composite Materials

    Microsoft Academic Search

    J. J. Nevadunsky; J. J. Lucas; M. J. Salkind

    1975-01-01

    Detection of early fatigue damage in composite materials by nondestructive inspection (NDI) techniques has been demonstrated for ±45° Glass\\/Epoxy, and ±45°\\/0° Graphite\\/Glass\\/Epoxy. Dynamic axial modulus and temperature were monitored continuously with a correlation between temperature rise and modulus decrease observed. The modulus decrease and temperature rise are indicative of irreversible damage in these materials.Torsional modulus measurements and coin tap tests

  3. Chemical composition of the lunar surface in mare tranquillitatis.

    PubMed

    Turkevich, A L; Franzgrote, E J; Patterson, J H

    1969-07-18

    More precise and comprehensive analytical results have been derived for lunar material at the Surveyor V landing site from alpha-scattering data. The composition is, in general, basaltic; the low sodium and high titanium contents, however, are distinctly different from the abundances in meteorites or common terrestrial rocks. PMID:17814825

  4. Reduced graphene oxide/tin oxide composite as an enhanced anode material for lithium ion batteries prepared by homogenous coprecipitation

    NASA Astrophysics Data System (ADS)

    Zhu, Xianjun; Zhu, Yanwu; Murali, Shanthi; Stoller, Meryl D.; Ruoff, Rodney S.

    2011-08-01

    Reduced graphene oxide/tin oxide composite is prepared by homogenous coprecipitation. Characterizations show that tin oxide particles are anchored uniformly on the surface of reduced graphene oxide platelets. As an anode material for Li ion batteries, it has 2140 mAh g-1 and 1080 mAh g-1 capacities for the first discharge and charge, respectively, which is more than the theoretical capacity of tin oxide, and has good capacity retention with a capacity of 649 mAh g-1 after 30 cycles. The simple synthesis method can be readily adapted to prepare other composites containing reduced graphene oxide as a conducting additive that, in addition to supporting metal oxide nanoparticles, can also provide additional Li binding sites to, perhaps, further enhance capacity.

  5. Gaseous composition measured by a chemical ionization mass spectrometer in fresh and aged ship plumes

    NASA Astrophysics Data System (ADS)

    Faxon, Cameron; Psichoudaki, Magda; Kuuluvainen, Heino; Hallquist, Åsa; Thomson, Erik; Pettersson, Jan; Hallquist, Mattias

    2015-04-01

    The port of Gothenburg is the largest port of the Nordic countries with numerous ships calling the port daily. The ship exhausts contain numerous pollutants including gases such as SO2 and NOx as well as particulate matter and soot. The exhaust also contains numerous organic compounds, a large fraction of which are unidentified. These organics are oxidized in the atmosphere producing more oxygenated and potentially less volatile compounds that may contribute to the secondary organic aerosol (SOA). This work focuses on the characterization of fresh gaseous species present in the exhaust plumes of the passing ships and also on their photochemical aging. Between 26 September and 12 November 2014 measurements were conducted at a sampling site located on a small peninsula at the entrance of Gothenburg's port. The campaign was divided in two periods. During the first period, the fresh plumes of the passing ships were measured through a main inlet. During the second period, the sample passed through the same inlet and was then introduced into a Potential Aerosol Mass (PAM) reactor. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the plumes. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in the current camping corresponded to 3.4 days in the atmosphere. A Time-of-Flight Chemical Ionization Mass Spectrometer (ToF-CIMS) was employed to monitor the concentration of different organic species present in the fresh and aged plumes. Water (positive) and iodide (negative) ionization methods were employed were water was primarily used for fresh plumes (large fraction of non-polar compounds) while iodide was used for the aged plumes (primarily oxidised products). The H2O, O3 and SO2 concentrations inside the PAM chamber were monitored, and an organic tracer for OH exposure determination was also continuously measured. The dominant species concentrations of both fresh and aged ship plumes are presented and their emission factors are estimated from concurrent CO2 measurements.

  6. Computer aided design of multifunctional composite materials

    Microsoft Academic Search

    V. V. Kafarov; I. N. Dorokhov; A. Ramirez; N. I. Kafarova

    1996-01-01

    This paper deal with a multicriterion compromise problem of production of a multifunctional material on the basis of a stochastic composite with several mutually distributed phases. A formal technique for solving this problem is proposed based on the methods of topological feedback, mathematical morphology, percolation theory, and the theory of discrete phase mappings. By way of illustration, this formal technique

  7. Chemical warfare agent and high explosive identification by spectroscopy of neutron-induced gamma rays

    Microsoft Academic Search

    A. J. Caffrey; J. D. Cole; R. J. Gehrke; R. C. Greenwood

    1992-01-01

    A nondestructive assay method to identify chemical warfare (CW) agents and high explosive (HE) munitions was tested with actual chemical agents and explosives. The assay method exploits the gamma radiation produced by neutron interactions inside a container or munition to identify the elemental composition of its contents. The characteristic gamma-ray signature of the chemical elements chlorine, phosphorus, and sulfur were

  8. Nondestructive estimation of wood chemical composition of sections of radial wood strips by diffuse reflectance near infrared spectroscopy

    Microsoft Academic Search

    P. David Jones; Laurence R. Schimleck; Gary F. Peter; Richard F. Daniels; Alexander Clark

    2006-01-01

    The use of calibrated near infrared (NIR) spectroscopy for predicting the chemical composition of Pinus taeda L. (loblolly pine) wood samples is investigated. Seventeen P. taeda radial strips, representing seven different sites were selected and NIR spectra were obtained from the radial longitudinal face of each strip. The spectra were obtained in 12.5 mm sections from pre-determined positions that represented juvenile

  9. New composite thermoelectric materials for energy harvesting applications

    Microsoft Academic Search

    M. S. Dresselhaus; G. Chen; Z. F. Ren; G. Dresselhaus; A. Henry; J.-P. Fleurial

    2009-01-01

    The concept of using nanostructured composite materials to enhance the dimensionless thermoelectric figure of merit ZT relative\\u000a to that for their counterpart homogeneous alloyed bulk crystalline materials of similar chemical composition is presented\\u000a in general terms. Specific applications are made to the Si-Ge and Bi2-?xSbxTe3 systems for use in high-temperature power generation and cooling applications. The scientific advantages of the

  10. Composite material heat pipe radiator

    NASA Astrophysics Data System (ADS)

    Gernert, Nelson J.; Sarraf, David B.; Guenther, Richard J.; Hurlbert/, Kathryn Miller

    1996-03-01

    Organic matrix composite material is recognized for its significant strength to weight ratio when compared to metal and consequently was investigated for reducing the mass of heat pipes for future space missions. The particular heat pipe that was constructed and tested was made from an organic matrix composite material applied to a linear of titanium tubing spun to foil thickness (0.076 mm). The thin liner transitioned to heavier-walled ends which allowed the tubing to be sealed using conventional welding. More specifically, the heat pipe was 1.14 m long, 24 mm in diameter and had a mass of 0.165 kg. Water was the working fluid. The heat pipe was tested in a Thermacore thermal vacuum chamber under hot and cold wall operating conditions. The heat load dissipated ranged from 10 to 60 watts. Heat pipe operating temperatures varied from 278 K to 403 K. After testing, the heat pipe was delivered to NASA JSC where future thermal vacuum chamber tests are planned.

  11. Predicting Jatropha curcas seed-oil content, oil composition and protein content using near-infrared spectroscopy—A quick and non-destructive method

    Microsoft Academic Search

    Yiftach Vaknin; Miriam Ghanim; Shahar Samra; Levana Dvash; Efrat Hendelsman; Dan Eisikowitch; Yael Samocha

    2011-01-01

    The potential of near-infrared reflectance spectroscopy (NIRS) to estimate the oil content, fatty acid composition, and protein content of Jatropha curcas seeds was studied. Seventy-four intact kernels from various sources were scanned by NIRS. All samples were analyzed for oil content (hexane extractions), fatty acid composition (gas chromatography), and protein content (Kjeldahl). Calibration equations were developed for oil content, individual

  12. Influence of silanated filler content on the biodegradation of bisGMA/TEGDMA dental composite resins.

    PubMed

    Finer, Y; Santerre, J P

    2007-04-01

    It has been shown that an increase in the content of nonsilanated submicron colloidal silica filler particles within dental composites resulted in the release of more bis-phenol-A diglycidyl dimethacrylate (bisGMA)-derived product, bis-hydroxy-propoxyphenyl propane, following incubation with cholesterol esterase (CE). This work further investigates the enzyme-catalyzed biodegradation of fine composite resin systems, containing silanated micron-size irregular glass fillers, commonly used in clinical restorations. Model composite resin samples (10 or 60% weight fraction silanated barium glass filler, 1 mum average particle size) based on bisGMA/triethylene glycol dimethacrylate (TEGDMA) were incubated in buffer or buffer with CE (pH = 7.0, 37 degrees C) solutions for 32 days. The incubation solutions were analyzed using high-performance liquid chromatography, UV spectroscopy, and mass spectrometry. Both groups were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. In contrast with previous findings for nonsilanated submicron filler systems, the higher filler containing composite showed an increase in its stability with time, following exposure to esterase and when compared to the lower filler content material. As well, the 60% filler composite leached less unreacted monomer TEGDMA. Since the model composite resins studied here were identical and only the filler content varied, the differences in biostability could be specifically associated with the relative amount of resin/filler distribution. The clinical use of different materials in varied dental applications (ranging from fissure sealant to tooth-colored highly filled materials) must consider the potential for different degradation profiles to occur as a function of filler content. PMID:17109416

  13. Subscriber access provided by DUKE UNIV Chemistry of Materials is published by the American Chemical Society. 1155 Sixteenth

    E-print Network

    Liu, Jie

    nanoparticles but also serves as a carrier to uniformly distribute iron-complexed polymer chains by spin of attention. CNTs have been exploited as novel building blocks for various applications including composite- ously formed by soaking a thermal silicon oxide surface in an iron salt solution12 and recently iron

  14. Yield and chemical composition of fractions from fermented shrimp biowaste.

    PubMed

    Narayan, Bhaskar; Velappan, Suresh Puthanveetil; Zituji, Sakhare Patiram; Manjabhatta, Sachindra Nakkerike; Gowda, Lalitha Ramakrishna

    2010-01-01

    Chemical composition of chitinous residue and fermentation liquor fractions, obtained from fermented shrimp biowaste, was evaluated in order to explore their potential for further utilization. Lyophilization of the liquor fraction obtained after fermentation resulted in a powder rich in both protein (30%) and carotenoids (217.18 +/- 2.89 microg/g). The yield of chitinous residue was 44% (w/w) whereas the yield of lyophilized powder was >25% (w/v). About 69% of total carotenoids were recovered by fermentation. Fermentation resulted in the removal of both protein as well as ash content from the shrimp biowaste, as indicated by approximately 92% deproteination and >76% demineralization, respectively. Post fermentation, the residue had a chitin content of >90%. The lyophilized liquor fraction had all the essential amino acids (except threonine) in quantities comparable to Food & Agriculture Organization/World Health Organization reference protein. The composition of fermentation liquor is indicative of its potential for application as an amino acid supplement in aquaculture feed formulations. PMID:19723823

  15. Effect of Chemical Treatments on Flax Fibre Reinforced Polypropylene Composites on Tensile and Dome Forming Behaviour

    PubMed Central

    Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

    2015-01-01

    Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

  16. Effect of chemical treatments on flax fibre reinforced polypropylene composites on tensile and dome forming behaviour.

    PubMed

    Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

    2015-01-01

    Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

  17. Chemical composition and pulping of banana pseudo-stems

    Microsoft Academic Search

    N Cordeiro; M. N Belgacem; I. C Torres; J. C. V. P Moura

    2004-01-01

    This paper deals with the determination of chemical composition and the study of the pulping potentialities of banana pseudo-stems growing in Madeira Island (Portugal). First, the raw material was both studied as a whole (type I) and as the outer bark part (type II), which is richer in cellulose fibres. Before starting the cooking of banana wastes, the main components

  18. POLYDIMETHYLSILOXANE-BASED SELF-HEALING COMPOSITE AND COATING MATERIALS

    E-print Network

    Braun, Paul

    POLYDIMETHYLSILOXANE-BASED SELF-HEALING COMPOSITE AND COATING MATERIALS BY SOO HYOUN CHO B-healing polymers by introducing tin catalyzed polycondensation of hydroxyl end- functionalized polydimethylsiloxane

  19. Ceramic composites: Enabling aerospace materials

    NASA Technical Reports Server (NTRS)

    Levine, S. R.

    1992-01-01

    Ceramics and ceramic matrix composites (CMC) have the potential for significant impact on the performance of aerospace propulsion and power systems. In this paper, the potential benefits are discussed in broad qualitative terms and are illustrated by some specific application case studies. The key issues in need of resolution for the potential of ceramics to be realized are discussed.

  20. The ideal ceramic-fibre\\/oxide-matrix composite: how to reconcile antagonist physical and chemical requirements?

    Microsoft Academic Search

    Philippe Colomban; Gwénael Gouadec

    2005-01-01

    Starting with a short historical introduction, this paper deals with the search for the best materials to be used in ceramic composites. The reinforcement and oxide matrix must satisfy multiple - and often antagonist - requirements in terms of physical (failure resistance, damage tolerance) and chemical (thermal stability, corrosion resistance) properties. The best compromise is obtained by \\

  1. Review on advanced composite materials boring mechanism and tools

    Microsoft Academic Search

    Runping Shi; Chengyong Wang

    2010-01-01

    With the rapid development of aviation and aerospace manufacturing technology, advanced composite materials represented by carbon fibre reinforced plastics (CFRP) and super hybrid composites (fibre\\/metal plates) are more and more widely applied. The fibres are mainly carbon fibre, boron fibre, Aramid fiber and Sic fibre. The matrixes are resin matrix, metal matrix and ceramic matrix. Advanced composite materials have higher

  2. Potential nutritional assessment of dwarf elephant grass ( Pennisetum purpureum Schum. cv. Mott) by chemical composition, digestion and net portal flux of oxygen in cattle

    Microsoft Academic Search

    G. V Kozloski; J Perottoni; M. L. S Ciocca; J. B. T Rocha; A. G Raiser; L. M. B Sanchez

    2003-01-01

    This study was conducted to evaluate changes in chemical composition of dwarf elephant grass hay cut at 30, 40, 50 and 60 days of growth, and its effect on apparent digestibility and particle-phase passage through the gastrointestinal tract (Experiment 1) and on oxygen utilization by the portal-drained viscera of cattle (Experiment 2). The experiments were carried out using four Holstein

  3. Graphene-based Composite Materials

    NASA Astrophysics Data System (ADS)

    Rafiee, Mohammad Ali

    We investigated the mechanical properties, such as fracture toughness (KIc), fracture energy (GIc), ultimate tensile strength (UTS), Young¡¦s modulus (E), and fatigue crack propagation rate (FCPR) of epoxy-matrix composites with different weight fractions of carbon-based fillers, including graphene platelets (GPL), graphene nanoribbons (GNR), single-walled carbon nanotubes (SWNT), multi-walled carbon nanotubes (MWNT), and fullerenes (C60). Only ˜0.125 wt.% GPL was found to increase the KIc of the pure epoxy by ˜65% and the GIc by ˜115%. To get similar improvement, CNT and nanoparticle epoxy composites required one to two orders of magnitude greater weight fraction of nanofillers. Moreover, ˜0.125% wt.% GPL also decreased the fatigue crack propagation rate in the epoxy by ˜30-fold. The E value of 0.1 wt.% GPL/epoxy nanocomposite was ˜31% larger than the pure epoxy while there was only an increase of ˜3% for the SWNT composites. The UTS of the pristine epoxy was improved by ˜40% with GPLs in comparison with ˜14% enhancement for the MWNTs. The KIc of the GPL nanocomposite enhanced by ˜53% over the pristine epoxy compared to a ˜20% increase for the MWNT-reinforced composites. The results of the FCPR tests for the GPL nanocomposites showed a different trend. While the CNT nanocomposites were not effective enough to suppress the crack growth at high values of the stress intensity factor (DeltaK), the reverse behavior is observed for the GPL nanocomposites. The advantage of the GPLs over CNTs in terms of mechanical properties enhancement is due to their enormous specific surface area, enhanced adhesion at filler/epoxy interface (because of the wrinkled surfaces of GPLs), as well as the planar structure of the GPLs. We also show that unzipping of MWNTs into graphene nanoribbons (GNRs) enhances the load transfer effectiveness in epoxy nanocomposites. For instance, at ˜0.3 wt.% of fillers, the Young's modulus (E) of the epoxy nanocomposite with GNRs increased by ˜30% compared to their MWNTs counterpart. The ultimate tensile strength (UTS) for ˜0.3 wt.% GNR composites showed ˜22% enhancement compared to the MWNT composites at the same loading fraction of fillers (at ˜0.3 wt.%). Our results show that unzipping effect can be used to transform carbon nanotubes into graphene nanoribbons, which are far more effective than the baseline nanotube as a nanofiller in nanocomposites. The mechanical properties of fullerence (C60) epoxy nanocomposites at different loading fractions (wt.%) of fullerene fillers in the pristine epoxy was also studied. Fullerene (C60) fillers demonstrated good potential to improve the mechanical properties of epoxy composites. However the required C60 loading fractions were ˜1% which are still an order of magnitude higher than that for graphene platelets (˜0.1%). This again illustrates the superiority of graphene as a structural reinforcement additive for epoxy polymers at low nanofiller loadings. While the main focus of this work has been on epoxy polymers, initial results with ceramic matrix and metal (aluminum) matrix composites were also generated. These results demonstrate that GPL are highly effective in enahncing the fracture properties of silicon nitride ceramics. The fracture toughness of the baseline silicon nitride matrix increased by ˜235% (from ˜2.8 to ˜6.6 MPa.m1/2) at ˜1.5% GPL volume fraction. However the results were disappointing for aluminim matrix composites. Compared to the pure aluminum, the graphene-aluminum composites showed decreased strength and hardness. This is explained in the context of enhanced aluminum carbide formation with the graphene filler. These results indicate that Graphene Platelets (GPL) show strong potential as a nanofiller for epoxy nanocomposites and can provide a performance comparable to other forms of nanofillers at a significantly lower nanofiller loading fraction.

  4. Nano composite phase change materials microcapsules

    NASA Astrophysics Data System (ADS)

    Song, Qingwen

    MicroPCMs with nano composite structures (NC-MicroPCMs) have been systematically studied. NC-MicroPCMs were fabricated by the in situ polymerization and addition of silver NPs into core-shell structures. A full factorial experiment was designed, including three factors of core/shell, molar ratio of formaldehyde/melamine and NPs addition. 12 MicroPCMs samples were prepared. The encapsulated efficiency is approximately 80% to 90%. The structural/morphological features of the NC-MicroPCMs were evaluated. The size was in a range of 3.4 mu m to 4.0 mu m. The coarse appearance is attributed to NPs and NPs are distributed on the surface, within the shell and core. The NC-MicroPCMs contain new chemical components and molecular groups, due to the formation of chemical bonds after the pretreatment of NPs. Extra X-ray diffraction peaks of silver were found indicating silver nano-particles were formed into an integral structure with the core/shell structure by means of chemical bonds and physical linkages. Extra functionalities were found, including: (1) enhancement of IR radiation properties; (2) depression of super-cooling, and (3) increase of thermal stabilities. The effects of SERS (Surface Enhanced Raman Spectroscopy) arising from the silver nano-particles were observed. The Raman scattering intensity was magnified more than 100 times. These effects were also exhibited in macroscopic level in the fabric coatings as enhanced IR radiation properties were detected by the "Fabric Infrared Radiation Management Tester" (FRMT). "Degree of Crystallinity" (DOC) was measured and found the three factors have a strong influence on it. DOC is closely related to thermal stability and MicroPCMs with a higher DOC show better temperature resistance. The thermal regulating effects of the MicroPCMs coatings were studied. A "plateau regions" was detected around the temperature of phase change, showing the function of PCMs. Addition of silver nano-particles to the MicroPCMs has a positive influence on it. NC-MicroPCMs with introducing silver nano particles into the MicroPCMs structure, have shown excellent multifunctional thermal properties and thermal stabilities that are far beyond those of the conventional MicroPCMs. The novel NC-MicroPCMs can be used to develop advanced smart materials and products with prosperous and promising applications in a number of industries.

  5. Determination of MWD and chemical composition of polymers by chromatographic techniques

    Microsoft Academic Search

    Bernd Trathnigg

    1995-01-01

    A review is given on the current developments in polymer characterization by chromatographic techniques, such as precipitation chromatography, (gradient) liquid adsorption chromatography, size exclusion chromatography, and liquid chromatography at the critical point of adsorption, as well as combination thereof. Special emphasis is devoted to hyphenated techniques, such as multiple detection and two-dimensional chromatography, and their potential in characterization of complex

  6. High-porosity powder-fiber composite materials

    Microsoft Academic Search

    A. G. Kostornov; N. E. Fedorova; L. I. Chernyshev

    1983-01-01

    The feasibility is demonstrated of substantially reducing volume changes during the sintering of high-porosity materials by the addition of fibers to a powder mixture. The mechanism of sintering of powder-fiber composites containing more than 25% of fibers is similar to the mechanism of sintering of pure fiber materials. The mechanical properties of permeable composite materials are determined by the fiber

  7. Measurement of chemical composition in wet whole maize silage by visible and near infrared reflectance spectroscopy

    Microsoft Academic Search

    D. Cozzolino; A. Fassio; E. Fernández; E. Restaino; A. La Manna

    2006-01-01

    Visible (Vis) and near infrared reflectance (NIR) spectroscopy were used to predict dry matter (DM), acid and neutral detergent fibre (ADFom and aNDFom), ash, crude protein (CP) and pH in wet whole maize (WWM) silage samples. Samples were analysed by reference methods and spectra collected using a NIR spectrophotometer in reflectance (400–2500nm). Predictive equations were developed using modified partial least

  8. Polyolefin composites containing a phase change material

    DOEpatents

    Salyer, Ival O. (Dayton, OH)

    1991-01-01

    A composite useful in thermal energy storage, said composite being formed of a polyolefin matrix having a phase change material such as a crystalline alkyl hydrocarbon incorporated therein, said polyolefin being thermally form stable; the composite is useful in forming pellets, sheets or fibers having thermal energy storage characteristics; methods for forming the composite are also disclosed.

  9. Pedagogical Content Knowledge in Teaching Material

    ERIC Educational Resources Information Center

    Saeli, Mara; Perrenet, Jacob; Jochems, Wim M. G.; Zwaneveld, Bert

    2012-01-01

    The scope of this article is to understand to what extent Computer Science teachers can find support for their Pedagogical Content Knowledge (PCK) in teaching material. We report the results of a study in which PCK is used as framework to develop a research instrument to examine three high school computer science textbooks, with special focus on…

  10. Chemical Composition of Tobacco Leaves Altered by Near-Ultraviolet and Intensity of Visible Light 1

    PubMed Central

    Andersen, Roger; Kasperbauer, M. J.

    1973-01-01

    Low energies of near-ultraviolet radiation (300-400 nanometers), applied simultaneously with visible radiation to Nicotiana tabacum L. during daily illumination periods, increased levels of chlorogenic acid isomers, total soluble phenolics, alkaloids, and soluble sugars in expanding leaf lamina compared with controls that had near-ultraviolet filtered out. However, total nitrogen concentrations decreased. The responses to near-ultraviolet were interrelated with intensity of visible light. The presence of near-ultraviolet (which accounted for less than 4% of the total light energy) along with visible light resulted in component concentration differences similar to those caused by much greater increases of visible light without near-ultraviolet. PMID:16658399

  11. Chemical composition, antimicrobial property and microencapsulation of Mustard (Sinapis alba) seed essential oil by complex coacervation.

    PubMed

    Peng, Chao; Zhao, Su-Qing; Zhang, Jun; Huang, Gui-Ying; Chen, Lan-Ying; Zhao, Feng-Yi

    2014-12-15

    In this study, the essential oil from mustard seed was isolated by simultaneous steam distillation and extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS). Fourteen components were identified in the mustard seed essential oil with allyl isothiocyanate being the main component (71.06%). The essential oil has a broad-spectrum antimicrobial activity with inhibition zones and MIC values in the range of 9.68-15.57 mm and 128-512 ?g/mL respectively. The essential oil was subsequently encapsulated in complex coacervation microcapsules with genipin, a natural water-soluble cross-linker. The optimum parameters for the hardening effectiveness of the genipin-hardened essential oil microcapsules were 8h at 40°C and pH 10.0 with a genipin concentration of 0.075 g/g gelatin. The genipin-hardened microcapsules had a particle size of mainly 5-10 ?m and strong chemistry stability which is potential for its application in food preservation. PMID:25038712

  12. Chemical composition and selected mechanical properties of Al-Zn alloy modified in plasma conditions by RF CVD

    NASA Astrophysics Data System (ADS)

    Kyzio?, Karol; Kluska, Stanis?awa; Janu?, Marta; ?roda, Marcin; Jastrz?bski, Witold; Kaczmarek, ?ukasz

    2014-08-01

    The paper reports results of the study of surface composition and selected functional properties of 7075 (Al-Zn) alloys modified in Ar, N2, SiH4 and CH4 atmosphere at reduced pressure. RF CVD (Radio Frequency Chemical Vapour Deposition) technique was used in the study. The type or weight percentage of carbon in each modification varied in the resultant SiN:H and SiCN:H coatings. Alloy samples were treated with Ar+ plasma etching and N+ ion implantation at reduced pressure. The tests proved the values of selected mechanical properties (hardness ca. 10.5 GPa, Young modulus ca. 95 GPa) and adhesion (delamination force ca. 11.5 mN) to be higher in the case of SiCN:H anti-wear coating (deposited in SiH4:CH4:N2 = 1:1:2 gas mixture) than the values of the respective parameters obtained in the remaining modifications. Further, carbon doped coatings (SiCN:H) exhibited significantly improved hardness (by about 50 to 70%) and nearly threefold increase in delamination force in comparison with SiCN:H coatings.

  13. Investigation of the chemical compositions in tobacco of different origins and maturities at harvest by GC-MS and HPLC-PDA-QTOF-MS.

    PubMed

    Xia, Bing; Feng, Mengmeng; Xu, Gang; Xu, Jindi; Li, Songlin; Chen, Xiaozhen; Ding, Lisheng; Zhou, Yan

    2014-06-01

    Tobacco samples of a same cultivar grown in different plantations in China were evaluated for their chemical compositions at different maturities for the first time. This was accomplished by a comprehensive and reliable method using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry (HPLC-PDA-QTOF-MS) to analyze the fat-soluble and polar components in 12 batches of tobacco samples of three origins and four maturities. The GC-MS analyses showed that tobacco samples harvested at 40 days after transplantation exhibited more fat-soluble components, while those harvested at 100 days after transplantation exhibited the least fat-soluble components. Tentatively, identification of the main components as well as quantitative analyses of eight reference compounds, including five alkaloids, two polyphenols, and a coumarin, was performed by the developed HPLC-QTOF-PDA method. Results showed significant differences among origins and maturities in the contents of these compounds. The nicotine contents showed great variety among the 12 tobacco samples. The highest nicotine content were found in a sample from Zhengzhou harvested at 40 days after transplantation (ZZ-T with 25399.39 ± 308.95 ?g/g), and the lowest nicotine level was detected in a sample from Zunyi harvested at 60 days after transplantation (ZY-X with 1654.49 ± 34.52 ?g/g). The highest level of rutin was found in a Jiangchuan sample harvested at 60 days after transplantation (JC-X with 725.93 ± 40.70 ?g/g), and the lowest rutin content was detected in a Zunyi tobacco sample harvested at 60 days after transplantation (ZY-X with 87.42 ± 2.78 ?g/g). The developed method provided a convenient approach which might be applied for rapid maturity evaluation and tobacco flavor identification and also holds the potential for analysis of compounds present in other plants. PMID:24833170

  14. Preparation of Aluminum Metal Matrix Composite with Novel In situ Ceramic Composite Particulates, Developed from Waste Colliery Shale Material

    NASA Astrophysics Data System (ADS)

    Venkata Siva, S. B.; Sahoo, K. L.; Ganguly, R. I.; Dash, R. R.; Singh, S. K.; Satpathy, B. K.; Srinivasarao, G.

    2013-08-01

    A novel method is adapted to prepare an in situ ceramic composite from waste colliery shale (CS) material. Heat treatment of the shale material, in a plasma reactor and/or in a high temperature furnace at 1673 K (1400 °C) under high vacuum (10-6 Torr), has enabled in situ conversion of SiO2 to SiC in the vicinity of carbon and Al2O3 present in the shale material. The composite has the chemical constituents, SiC-Al2O3-C, as established by XRD/EDX analysis. Particle sizes of the composite range between 50 nm and 200 ?m. The shape of the particles vary, presumably rod to spherical shape, distributed preferably in the region of grain boundaries. The CS composite so produced is added to aluminum melt to produce Al-CS composite (12 vol. pct). For comparison of properties, the aluminum metal matrix composite (AMCs) is made with Al2O3 particulates (15 vol. pct) with size <200 ?m. The heat-treated Al-CS composite has shown better mechanical properties compared to the Al-Al2O3 composite. The ductility and toughness of the Al-CS composite are greater than that of the Al-Al2O3 composite. Fractographs revealed fine sheared dimples in the Al-CS composite, whereas the same of the Al-Al2O3 composite showed an appearance of cleavage-type facets. Abrasion and frictional behavior of both the composites have been compared. The findings lead to the conclusion that the in situ composite developed from the colliery shale waste material has a good future for its use in AMCs.

  15. Carbon Materials Metal/Metal Oxide Nanoparticle Composite and Battery Anode Composed of the Same

    NASA Technical Reports Server (NTRS)

    Hung, Ching-Cheh (Inventor)

    2006-01-01

    A method of forming a composite material for use as an anode for a lithium-ion battery is disclosed. The steps include selecting a carbon material as a constituent part of the composite, chemically treating the selected carbon material to receive nanoparticles, incorporating nanoparticles into the chemically treated carbon material and removing surface nanoparticles from an outside surface of the carbon material with incorporated nanoparticles. A material making up the nanoparticles alloys with lithium.

  16. Subscriber access provided by UNIV OF SOUTHERN CALIFORNIA Chemistry of Materials is published by the American Chemical Society. 1155

    E-print Network

    Zhou, Chongwu

    by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Article Bicrystalline Zn 3 P 2, novel bicrystalline Zn3P2 and Cd3P2 nanobelts were synthesized in a vertical induction furnace14 via

  17. Monojoy Goswami Computational Chemical and Materials Sciences

    E-print Network

    Pennycook, Steve

    Monojoy Goswami Computational Chemical and Materials Sciences Center for Nanophase Materials: Computational Chemical and Materials Sciences: Large-scale molecular dynamics (MD) simulations to understand Sciences Oak Ridge National Laboratory (865) 576-3265 goswamim@ornl.gov Publications Education: Institute

  18. Shape memory materials and hybrid composites for smart systems: Part II Shape-memory hybrid composites

    Microsoft Academic Search

    Z. G. Wei; R. Sandstrom; S. Miyazaki

    1998-01-01

    By hybridizing or incorporating shape-memory materials with other functional materials or structural materials, smart composites can be fabricated which may utilize the unique functions or properties of the individual bulk materials to achieve multiple responses and optimal properties, or, to tune their properties to adapt to environmental changes. A variety of shape-memory hybrid composites have been designed and manufactured, with

  19. CHEMICAL COMPOSITION OF SOYBEAN GENOTYPES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At the National Center for Soybean Research at EMBRAPA (Brazilian Agricultural Research Corporation), efforts are being done to increase soybean consumption in Brazil. Through the breeding of specialty soybean cultivars, BRS 155, which has reduced content of trypsin inhibitor; BRS 213, which is nul...

  20. Detection of adulteration of pumpkin seed oil by analysis of content and composition of specific ?7-phytosterols

    Microsoft Academic Search

    Alexandra Mandl; Gregor Reich; W. Lindner

    1999-01-01

    A simple and accurate method for the determination of phytosterols by capillary gas chromatography was developed for the\\u000a analysis of the seeds and oil of the pumpkin Cucurbita pepo L., the naked seed variety growing in the southern Styrian parts of Austria. After extraction of the oil and saponification,\\u000a the remaining unsaponifiable material was isolated and purified using silica gel

  1. Conductor-polymer composite electrode materials

    DOEpatents

    Ginley, D.S.; Kurtz, S.R.; Smyrl, W.H.; Zeigler, J.M.

    1984-06-13

    A conductive composite material useful as an electrode, comprises a conductor and an organic polymer which is reversibly electrochemically dopable to change its electrical conductivity. Said polymer continuously surrounds the conductor in intimate electrical contact therewith and is prepared by electrochemical growth on said conductor or by reaction of its corresponding monomer(s) on said conductor which has been pre-impregnated or pre-coated with an activator for said polymerization. Amount of the conductor is sufficient to render the resultant composite electrically conductive even when the polymer is in an undoped insulating state.

  2. Chemical composition and antibacterial activity of Gongronema latifolium

    Microsoft Academic Search

    Afolabi F. Eleyinmi

    2007-01-01

    Chemical composition of Gongronema latifolium leaves was determined using standard methods. Aqueous and methanol G. latifolium extracts were tested against thirteen pathogenic bacterial isolates. Crude protein, lipid extract, ash, crude fibre and nitrogen\\u000a free extractives obtained are: 27.2%, 6.07%, 11.6%, 10.8% and 44.3% dry matter respectively. Potassium, sodium, calcium, phosphorus\\u000a and cobalt contents are 332, 110, 115, 125 and 116

  3. Differences in Chemical Composition of Soil Organic Carbon Resulting From Long-Term Fertilization Strategies

    PubMed Central

    Li, Zengqiang; Zhao, Bingzi; Wang, Qingyun; Cao, Xiaoyan; Zhang, Jiabao

    2015-01-01

    Chemical composition of soil organic carbon (SOC) is central to soil fertility. We hypothesize that change in SOC content resulting from various long-term fertilization strategies accompanies the shift in SOC chemical structure. This study examined the effect of fertilization strategies along with the time of fertilizer application on the SOC composition by 13C nuclear magnetic resonance (NMR) spectroscopy. The soils (Aquic Inceptisol) subjected to seven fertilizer treatments were collected in 1989, 1999 and 2009, representing 0, 10 and 20 years of fertilization, respectively. The seven fertilizer treatments were (1–3) balanced fertilization with application of nitrogen (N), phosphorus (P) and potassium (K) including organic compost (OM), half organic compost plus half chemical fertilizer (1/2OM), and pure chemical NPK fertilizer (NPK); (4–6) unbalanced chemical fertilization without application of one of the major elements including NP fertilizer (NP), PK fertilizer (PK), and NK fertilizer (NK); and (7) an unamended control (CK). The SOC content in the balanced fertilization treatments were 2.3–52.6% and 9.4–64.6% higher than in the unbalanced fertilization/CK treatments in 1999 and 2009, respectively, indicating significant differences in SOC content with time of fertilizer application between the two treatment groups. There was a significantly greater proportion of O-alkyl C and a lower proportion of aromatic C in the balanced fertilization than in unbalanced fertilization/CK treatments in 1999, but not in 2009, because their proportions in the former treatments approached the latter in 2009. Principal component analysis further showed that the C functional groups from various fertilization strategies tended to become compositionally similar with time. The results suggest that a shift in SOC chemical composition may be firstly dominated by fertilization strategies, followed by fertilization duration. PMID:25884713

  4. Possibility of obtaining monolithic composite materials based on niobium carbide

    Microsoft Academic Search

    V. V. Ploshkin; I. Yu. Ul'yanina; V. P. Filonenko

    1984-01-01

    1.Specimens of composite material based on niobium carbide obtained by hydrostatic pressing had minimum porosity compared with specimens obtained by the normal powder metallurgy method.2.Basic phases of the composite material consisting of copper and niobium carbide are uniformly distributed throughout the specimen cross section and they do not react with each other under any conditions.3.The composite material obtained exhibits sufficient

  5. Comparison of composite polysaccharide-based materials for tissue engineering by means of texture analysis

    Microsoft Academic Search

    F. Brun; A. Accardo; G. Turco; S. Paoletti

    \\u000a Scaffold materials play a significant role in tissue regeneration, therefore it is crucial to investigate their morphological\\u000a characteristics and properties. Recently a particular interest has been raised for materials based on two oppositely charged\\u000a polysaccharides: alginate and chitosan. In the present paper the morphological characteristics of a pure alginate gel and\\u000a a binary (gel) mixture composed of alginate and chitosan

  6. Dielectric breakdown model for composite materials.

    PubMed

    Peruani, F; Solovey, G; Irurzun, I M; Mola, E E; Marzocca, A; Vicente, J L

    2003-06-01

    This paper addresses the problem of dielectric breakdown in composite materials. The dielectric breakdown model was generalized to describe dielectric breakdown patterns in conductor-loaded composites. Conducting particles are distributed at random in the insulating matrix, and the dielectric breakdown propagates according to new rules to take into account electrical properties and particle size. Dielectric breakdown patterns are characterized by their fractal dimension D and the parameters of the Weibull distribution. Studies are carried out as a function of the fraction of conducting inhomogeneities, p. The fractal dimension D of electrical trees approaches the fractal dimension of a percolation cluster when the fraction of conducting particles approximates the percolation limit. PMID:16241318

  7. Chemical composition of aerosols in the near-water surface atmospheric layer of the central Caspian Sea in the winter and autumn of 2005

    NASA Astrophysics Data System (ADS)

    Lukashin, V. N.; Novigatsky, A. N.

    2013-11-01

    The chemical composition (43 elements) of aerosols is reviewed for the Caspian Sea based on nine samples taken in the winter and autumn of 2005. The aerosols are considered as geological material incoming to the sea from the atmosphere. The major aerosol components are distinguished and the degree of the concentration is calculated for a series of trace elements relative to their contents in the lithosphere. Se, Cd, Sb, Au, and Pb are concentrated by one-two orders of magnitude, which is related to the pollution. A correlation matrix is given for the studied elements, and their relations with the major components of the aerosols are revealed.

  8. Single-walled carbon nanotube networks in conductive composite materials.

    PubMed

    Bârsan, Oana A; Hoffmann, Günter G; van der Ven, Leo G J; de With, G Bert

    2014-01-01

    Electrically conductive composite materials can be used for a wide range of applications because they combine the advantages of a specific polymeric material (e.g., thermal and mechanical properties) with the electrical properties of conductive filler particles. However, the overall electrical behaviour of these composite materials is usually much below the potential of the conductive fillers, mainly because by mixing two different components, new interfaces and interphases are created, changing the properties and behaviours of both. Our goal is to characterize and understand the nature and influence of these interfaces on the electrical properties of composite materials. We have improved a technique based on the use of sodium carboxymethyl cellulose (CMC) to disperse single-walled carbon nanotubes (SWCNTs) in water, followed by coating glass substrates, and drying and removing the CMC with a nitric acid treatment. We used electron microscopy and atomic force microscopy techniques to characterize the SWCNT films, and developed an in situ resistance measurement technique to analyse the influence of both the individual components and the mixture of an epoxy/amine system on the electrical behaviour of the SWCNTs. The results showed that impregnating a SWCNT network with a polymer is not the only factor that affects the film resistance; air exposure, temperature, physical and chemical properties of the individual polymer components, and also the formation of a polymeric network, can all have an influence on the macroscopic electrical properties of the initial SWCNT network. These results emphasize the importance of understanding the effects that each of the components can have on each other before trying to prepare an efficient polymer composite material. PMID:25430670

  9. Morphology and microstructure of composite materials

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Srinivansan, K.

    1991-01-01

    Lightweight continuous carbon fiber based polymeric composites are currently enjoying increasing acceptance as structural materials capable of replacing metals and alloys in load bearing applications. As with most new materials, these composites are undergoing trials with several competing processing techniques aimed at cost effectively producing void free consolidations with good mechanical properties. As metallic materials have been in use for several centuries, a considerable database exists on their morphology - microstructure; and the interrelationships between structure and properties have been well documented. Numerous studies on composites have established the crucial relationship between microstructure - morphology and properties. The various microstructural and morphological features of composite materials, particularly those accompanying different processing routes, are documented.

  10. Alkali metal protective garment and composite material

    SciTech Connect

    Ballif, J.L.; Yuan, W.W.

    1980-09-16

    A protective garment and composite material providing satisfactory heat resistance and physical protection for articles and personnel exposed to hot molten alkali metals, such as sodium are described. Physical protection is provided by a continuous layer of nickel foil. Heat resistance is provided by an underlying backing layer of thermal insulation. Overlying outer layers of fireproof woven ceramic fibers are used to protect the foil during storage and handling.

  11. Elementary damping properties in braided composite materials

    NASA Astrophysics Data System (ADS)

    Dion, Bernard L.; Sadler, Robert; Silverberg, Larry

    1994-05-01

    This paper investigates the damping level trends of three-dimensionally braided composites as a function of matrix material, fiber-matrix interface, fiber braid angle, fiber volume, and axial fiber tow size. With knowledge of such trends, designers may increase the structural damping in a 3-D braided composite component, thereby reducing component vibration, shock response, and fatigue. The logarithmic decrements of the fundamental mode response of cantilevered, 3-D braided composite beam specimens were calculated for comparison. Although the logarithmic decrements of two specimens, differing only in their matrix materials (Tactix 123 and Epon 828), were essentially identical, both were considerably larger than that for steel. The value for the decrement of these two composite specimens' response was taken as a reference. Altering the nature of the fiber-matrix interface by lubricating the fibers before specimen consolidation greatly increased the damping relative to the baseline. Trends of increasing damping were measured with both increasing fiber braid angle and fiber volume. Finally, increasing levels of damping are reported for decreases in axial fiber tow size. Explanations for these trends, based on the possible microscopic and macroscopic nature of the braided composites, are offered.

  12. Chemical composition of indigenous wild herbs, spices, fruits, nuts and leafy vegetables used as food

    Microsoft Academic Search

    S. C. Achinewhu; C. C. Ogbonna; A. D. Hart

    1995-01-01

    Thirty wild fruits, nuts, herbs, spices and leafy vegetables were characterized and their chemical composition determined. Some of them were not only used for food, but for medicine in minor aliments by the natives. Results of the proximate analysis showed that on dry weight basis, the crude protein content ranged from 4.6 to 22.1 percent for spices and herbs, 3.2

  13. Composite structural materials. [fiber reinforced composites for aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1981-01-01

    Physical properties of fiber reinforced composites; structural concepts and analysis; manufacturing; reliability; and life prediction are subjects of research conducted to determine the long term integrity of composite aircraft structures under conditions pertinent to service use. Progress is reported in (1) characterizing homogeneity in composite materials; (2) developing methods for analyzing composite materials; (3) studying fatigue in composite materials; (4) determining the temperature and moisture effects on the mechanical properties of laminates; (5) numerically analyzing moisture effects; (6) numerically analyzing the micromechanics of composite fracture; (7) constructing the 727 elevator attachment rib; (8) developing the L-1011 engine drag strut (CAPCOMP 2 program); (9) analyzing mechanical joints in composites; (10) developing computer software; and (11) processing science and technology, with emphasis on the sailplane project.

  14. Research on the Interaction of Hydrogen-Bond Acidic Polymer Sensitive Sensor Materials with Chemical Warfare Agents Simulants by Inverse Gas Chromatography

    PubMed Central

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  15. Research on the interaction of hydrogen-bond acidic polymer sensitive sensor materials with chemical warfare agents simulants by inverse gas chromatography.

    PubMed

    Yang, Liu; Han, Qiang; Cao, Shuya; Huang, Feng; Qin, Molin; Guo, Chenghai; Ding, Mingyu

    2015-01-01

    Hydrogen-bond acidic polymers are important high affinity materials sensitive to organophosphates in the chemical warfare agent sensor detection process. Interactions between the sensor sensitive materials and chemical warfare agent simulants were studied by inverse gas chromatography. Hydrogen bonded acidic polymers, i.e., BSP3, were prepared for micro-packed columns to examine the interaction. DMMP (a nerve gas simulant) and 2-CEES (a blister agent simulant) were used as probes. Chemical and physical parameters such as heats of absorption and Henry constants of the polymers to DMMP and 2-CEES were determined by inverse gas chromatography. Details concerning absorption performance are also discussed in this paper. PMID:26043177

  16. Using Composite Materials in a Cryogenic Pump

    NASA Technical Reports Server (NTRS)

    Batton, William D.; Dillard, James E.; Rottmund, Matthew E.; Tupper, Michael L.; Mallick, Kaushik; Francis, William H.

    2008-01-01

    Several modifications have been made to the design and operation of an extended-shaft cryogenic pump to increase the efficiency of pumping. In general, the efficiency of pumping a cryogenic fluid is limited by thermal losses which is itself caused by pump inefficiency and leakage of heat through the pump structure. A typical cryogenic pump includes a drive shaft and two main concentric static components (an outer pressure containment tube and an intermediate static support tube) made from stainless steel. The modifications made include replacement of the stainless-steel drive shaft and the concentric static stainless-steel components with components made of a glass/epoxy composite. The leakage of heat is thus reduced because the thermal conductivity of the composite is an order of magnitude below that of stainless steel. Taking advantage of the margin afforded by the decrease in thermal conductivity, the drive shaft could be shortened to increase its effective stiffness, thereby increasing the rotordynamic critical speeds, thereby further making it possible to operate the pump at a higher speed to increase pumping efficiency. During the modification effort, an analysis revealed that substitution of the shorter glass/epoxy shaft for the longer stainless-steel shaft was not, by itself, sufficient to satisfy the rotordynamic requirements at the desired increased speed. Hence, it became necessary to increase the stiffness of the composite shaft. This stiffening was accomplished by means of a carbon-fiber-composite overwrap along most of the length of the shaft. Concomitantly with the modifications described thus far, it was necessary to provide for joining the composite-material components with metallic components required by different aspects of the pump design. An adhesive material formulated specially to bond the composite and metal components was chosen as a means to satisfy these requirements.

  17. CRC materials science and engineering handbook. Third edition

    SciTech Connect

    Shackelford, J.F.; Alexander, W. (eds.)

    1999-01-01

    This definitive reference is organized in an easy-to-follow format based on materials properties. It features new and existing data verified through major professional societies in the materials fields, such as ASM International and the American Ceramic Society. The third edition has been significantly expanded, most notably by the addition of new tabular material for a wide range of nonferrous alloys and various materials. The contents include: Structure of materials; Composition of materials; Phase diagram sources; Thermodynamic and kinetic data; Thermal properties of materials; Mechanical properties of materials; Electrical properties of materials; Optical properties of materials; Chemical properties of materials.

  18. Tensile Strength of Glass Fiber-Reinforced Plastic by Fiber Orientation and Fiber Content Variations

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Woo; Kim, Hyoung-Seok; Lee, Dong-Gi

    For unidirectional composite material, there is a theoretical mixture rule equation to calculate the strength of composite from properties of matrix and fiber content. However, the equation for tensile strength with the fiber content and the fiber orientation is not available. Therefore, this study was investigated what affect fiber content and fiber orientation have on the strength of composites. Glass fiber-reinforced plastic by changing fiber orientation and fiber content was made. Tensile strength of 0° direction of composites increased being proportional fiber content and fiber orientation function as change from isotropy (J=0) to anisotropy (J=1). But, tensile strength of 90° direction by separation of fiber filament decreased when tensile load is imposed for width direction of reinforcement fiber length direction. In this study, empirical equation to estimate tensile strength out of fiber orientation and fiber content was proposed.

  19. (Proceedings of the 5th Technical Conference on Composite Materials, American Society of Composites,

    E-print Network

    Nairn, John A.

    ]s. The first material system was supplied by DuPont and consisted of AvimidR K Polymer/IM6 graphite fiber(Proceedings of the 5th Technical Conference on Composite Materials, American Society of Composites, East Lansing, Michigan, June 11-14, 1990). Fracture Mechanics Analysis of Composite Microcracking

  20. EFFECTS OF TOUGHENED MATRIX RESINS ON COMPOSITE MATERIALS FOR WIND TURBINE BLADES

    E-print Network

    EFFECTS OF TOUGHENED MATRIX RESINS ON COMPOSITE MATERIALS FOR WIND TURBINE BLADES by Ricardo Orozco. Finally, I would like to thank Sandia National Laboratories for supporting this research and the wind turbine energy project. #12;v TABLE OF CONTENTS LIST OF TABLES

  1. Characterization of enzymatic saccharification for acid-pretreated lignocellulosic materials with different lignin composition

    Microsoft Academic Search

    Gia-Luen Guo; Deng-Chieh Hsu; Wen-Hua Chen; Wei-Hsi Chen; Wen-Song Hwang

    2009-01-01

    The enzymatic saccharification of three different feedstocks, rice straw, bagasse and silvergrass, which had been pretreated with different dilute acid concentrations, was studied to verify how enzymatic saccharification was affected by the lignin composition of the raw materials. There was a quantitatively inverse correlation between lignin content and enzymatic digestibility after pretreatment with 1%, 2% and 4% sulfuric acid. The

  2. Wave propagation and impact in composite materials

    NASA Technical Reports Server (NTRS)

    Moon, F. C.

    1975-01-01

    Anisotropic waves in composites are considered, taking into account wave speeds, wave surfaces, flexural waves in orthotropic plates, surface waves, edge waves in plates, and waves in coupled composite plates. Aspects of dispersion in composites are discussed, giving attention to pulse propagation and dispersion, dispersion in rods and plates, dispersion in a layered composite, combined material and structural dispersion, continuum theories for composites, and variational methods for periodic composites. The characteristics of attenuation and scattering processes are examined and a description is given of shock waves and impact problems in composites. A number of experiments are also reported.

  3. Degradation of experimental composite materials and in vitro wear simulation

    NASA Astrophysics Data System (ADS)

    Givan, Daniel Allen

    2001-12-01

    The material, mechanical, and clinical aspects of surface degradation of resin composite dental restorative materials by in vitro wear simulation continues to be an area of active research. To investigate wear mechanisms, a series of experimental resin composites with variable and controlled filler particle shape and loading were studied by in vitro wear simulation. The current investigation utilized a simulation that isolated the wear environment, entrapped high and low modulus debris, and evaluated the process including machine and fluid flow dynamics. The degradation was significantly affected by filler particle shape and less by particle loading. The spherical particle composites demonstrated wear loss profiles suggesting an optimized filler loading may exist. This was also demonstrated by the trends in the mechanical properties. Very little difference in magnitude was noted for the wear of irregular particle composites as a function of particulate size; and as a group they were more wear resistant than spherical particle composites. This was the result of different mechanisms of wear that were correlated with the three-dimensional particle shape. The abrasive effects of the aggregate particles and the polymeric stabilization of the irregular shape versus the destabilization and "plucking" of the spherical particles resulted in an unprotected matrix that accounted for significantly greater wear of spherical composite. A model and analysis was developed to explain the events associated with the progressive material wear loss. The initial phase was explained by fatigue-assisted microcracking and loss of material segments in a zone of high stress immediately beneath a point of high stress contact. The early phase was characterized by the development of a small facet primarily by fatigue-assisted microcracking. Although the translation effects were minimal, some three-body and initial two-body wear events were also present. In the late phases, the abrasive effects of the debris aggregate predominated the wear process. The non-linear rate of wear loss was accelerated as the facet deepened. Physical effects, such as thermal fatigue, and chemical effects were less important but contributed to the degradation process. This study provides new insight into the role(s) of high modulus third body debris in the wear of dental composites.

  4. Development of composite materials by mechanochemical treatment of post-consumer plastic waste

    Microsoft Academic Search

    F Cavalieri; F Padella

    2002-01-01

    Improvement of mechanical properties of recycled mixed plastic waste is one of the fundamental goals in any recycling process. However, polymer immiscibility makes the development of any effective reprocessing method difficult. In this work, a polymer milling process with liquid CO2 was applied to polymeric mixed waste, obtaining a powder material which was successfully utilized as a matrix for a

  5. Compression Testing of Textile Composite Materials

    NASA Technical Reports Server (NTRS)

    Masters, John E.

    1996-01-01

    The applicability of existing test methods, which were developed primarily for laminates made of unidirectional prepreg tape, to textile composites is an area of concern. The issue is whether the values measured for the 2-D and 3-D braided, woven, stitched, and knit materials are accurate representations of the true material response. This report provides a review of efforts to establish a compression test method for textile reinforced composite materials. Experimental data have been gathered from several sources and evaluated to assess the effectiveness of a variety of test methods. The effectiveness of the individual test methods to measure the material's modulus and strength is determined. Data are presented for 2-D triaxial braided, 3-D woven, and stitched graphite/epoxy material. However, the determination of a recommended test method and specimen dimensions is based, primarily, on experimental results obtained by the Boeing Defense and Space Group for 2-D triaxially braided materials. They evaluated seven test methods: NASA Short Block, Modified IITRI, Boeing Open Hole Compression, Zabora Compression, Boeing Compression after Impact, NASA ST-4, and a Sandwich Column Test.

  6. New Micro Structural Design Concept for Polycrystalline Composite Materials

    Microsoft Academic Search

    A. N. RYBJANETS; A. V. NASEDKIN; A. V. TURIK

    2004-01-01

    A new concept of microstructural designing of polymer-free polycrystalline composite materials is offered. The concept based on controllable substitution during composite formation of separate crystallites making a polycrystal by pores, crystallites with other composition and\\/or structure or amorphous substances with preliminary FEM modeling of polycrystalline composite properties. A line of precursor small-scale production technologies and polycrystalline composites with unique and

  7. Changes in chemical composition and digestibility of three maize stover components digested by white-rot fungi.

    PubMed

    Lynch, J P; O'Kiely, P; Murphy, R; Doyle, E M

    2014-08-01

    Maize stover (total stem and leaves) is not considered a ruminant feed of high nutritive value. Therefore, an improvement in its digestibility may increase the viability of total forage maize production systems in marginal growth regions. The objective of this study was to describe the changes in chemical composition during the storage of contrasting components of maize stover (leaf, upper stem and lower stem) treated with either of two lignin degrading white-rot fungi (WRF; Pleurotus ostreatus, Trametes versicolor). Three components of maize stover (leaf, upper stem and lower stem), harvested at a conventional maturity for silage production, were digested with either of two WRF for one of four digestion durations (1-4 months). Samples taken prior to fungal inoculation were used to benchmark the changes that occurred. The degradation of acid detergent lignin was observed in all sample types digested with P. ostreatus; however, the loss of digestible substrate in all samples inoculated with P. ostreatus was high, and therefore, P. ostreatus-digested samples had a lower dry matter digestibility than samples prior to inoculation. Similarly, T. veriscolor-digested leaf underwent a non-selective degradation of the rumen-digestible components of fibre. The changes in chemical composition of leaf, upper stem and lower stem digested with either P. ostreatus or T. veriscolor were not beneficial to the feed value of the forage, and incurred high DM losses. PMID:24112093

  8. Research on Microstructure and Property of Fe-VC Composite Material Made by Laser Cladding

    NASA Astrophysics Data System (ADS)

    Zhang, Wei

    The experiment of laser cladding on the surface of H13 steel was made. Vanadium carbide (VC) powder and Fe-base alloy powder were used as cladding material. The microstructure and property of laser cladding layer were studied. The research showed that laser cladding layer had better properties such as minute crystals, deeper layer, higher hardness and good metallurgical bonding with base metal. The average hardness of cladding zone was 900HV0.2. The average hardness of cladding layer increased five times than that of base material. H13 steel was widely used in the field of hot dies. Using laser cladding, the good wear layer would greatly increase the mold useful life.

  9. Mechanics Methodology for Textile Preform Composite Materials

    NASA Technical Reports Server (NTRS)

    Poe, Clarence C., Jr.

    1996-01-01

    NASA and its contractors have completed a program to develop a basic mechanics underpinning for textile composites. Three major deliverables were produced by the program: 1. A set of test methods for measuring material properties and design allowables; 2. Mechanics models to predict the effects of the fiber preform architecture and constituent properties on engineering moduli, strength, damage resistance, and fatigue life; and 3. An electronic data base of coupon type test data. This report describes these three deliverables.

  10. DEPARTMENT OF CHEMICAL AND MATERIALS ENGINEERING

    E-print Network

    Beaucage, Gregory

    -disciplines, such as teaching, curriculum, alumni affairs, undergraduate professional activities, undergraduate scholarships1 BYLAWS OF THE DEPARTMENT OF CHEMICAL AND MATERIALS ENGINEERING JULY 18, 2007 #12;2 BYLAWS OF THE DEPARTMENT OF CHEMICAL AND MATERIALS ENGINEERING UNIVERSITY OF CINCINNATI, CINCINNATI, OHIO, USA 1. BYLAWS

  11. ZnxCd1-xSe alloy nanowires covering the entire compositional range grown by metalorganic chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Shan, C. X.; Liu, Z.; Ng, C. M.; Hark, S. K.

    2005-07-01

    We show that preferentially oriented, single-crystalline ZnxCd1-xSe alloy nanowires can be grown on GaAs (100) surface using Au as a catalyst over the entire compositional range in a metalorganic chemical vapor deposition system. The composition of the alloy nanowires can be simply adjusted through the ratio of the flow rates of group-II precursors. Electron microscopy shows that the nanowires are smooth and uniform in shape; their diameters range from 20 to 80 nm and lengths exceed a few micrometers. Nanowires containing more than 13% Zn are zinc blende structured and grow along the ?110? direction. Those containing less Zn are wurtzite structured and grow along the ?210? direction. Compared with the bulk alloy, the change from zinc blende to wurtzite structure in nanowires occurs at far smaller x. The preferred orientation and the persistence of the zinc blende structure both reflect the influence of the substrate on the growth of the nanowires. Photoluminescence measurements identify a strong near-band-edge emission for all samples and show that its peak energy tracks the band gap of ZnxCd1-xSe epilayer for x>0.13. The growth of alloy nanowires at many compositions opens up the possibility of realizing quasi-one-dimensional heterojunctions.

  12. Control of carbon content in amorphous GeTe films deposited by plasma enhanced chemical vapor deposition (PE-MOCVD) for phase-change random access memory applications

    NASA Astrophysics Data System (ADS)

    Aoukar, M.; Szkutnik, P. D.; Jourde, D.; Pelissier, B.; Michallon, P.; Noé, P.; Vallée, C.

    2015-07-01

    Amorphous and smooth GeTe thin films are deposited on 200?mm silicon substrates by plasma enhanced—metal organic chemical vapor deposition (PE–MOCVD) using the commercial organometallic precursors TDMAGe and DIPTe as Ge and Te precursors, respectively. X-ray photoelectron spectroscopy (XPS) measurements show a stoichiometric composition of the deposited GeTe films but with high carbon contamination. Using information collected by Optical Emission Spectroscopy (OES) and XPS, the origin of carbon contamination is determined and the dissociation mechanisms of Ge and Te precursors in H2 + Ar plasma are proposed. As a result, carbon level is properly controlled by varying operating parameters such as plasma radio frequency power, pressure and H2 rate. Finally, GeTe films with carbon level as low as 5?at. % are obtained.

  13. Improvement of the chemical content prediction of a model powder system by reducing multiple scattering using polarized light spectroscopy.

    PubMed

    Bendoula, Ryad; Gobrecht, Alexia; Moulin, Benoit; Roger, Jean-Michel; Bellon-Maurel, Veronique

    2015-01-01

    Near-infrared spectroscopy (NIRS) is a powerful non-destructive analytical method used to analyze major compounds in bulk materials and products and requiring no sample preparation. It is widely used in routine analysis and also in line in industries, in vivo with biomedical applications, or in field for agricultural and environmental applications. However, highly scattering samples subvert Beer-Lambert law's linear relationship between spectral absorbance and the concentration. Instead of spectral pre-processing, which is commonly used by NIR spectroscopists to mitigate the scattering effect, we put forward an optical method, i.e., coupling polarized light with NIR spectrometry, to free spectra from scattering effect. This should allow us to retrieve linear and steady conditions for spectral analysis. When tested in visible-NIR (Vis-NIR) range (400-800 nm) on model media, mixtures of scattering and absorbing particles, the setup provided significant improvements in absorber concentration estimation precision as well as in the quality and robustness of the calibration model. PMID:25498765

  14. Chemical Composition of South Polar Snow

    Microsoft Academic Search

    A. T. Wilson; D. A. House

    1965-01-01

    The chemical composition of south polar snow is of interest because of the remoteness of the snow from the earth's oceans, being at an altitude of 2700 m and a distance of 1600 km from the ocean in summer and twice that distance in winter. Unlike measurements made at the centers of other large continents, measurements made at the South

  15. Development of Si-Ti-C-O fiber reinforced SiC composites by chemical vapor infiltration and polymer impregnation & pyrolysis

    SciTech Connect

    Masaki, S.; Moriya, K.; Yamamura, T. [Research Institute of Advanced Material Gas-Generator, Tokyo (Japan)

    1995-12-01

    Continuous Si-Ti-C-O fiber reinforced SiC matrix composites were developed and evaluated. Three dimensional woven fabrics with carbon interface prepared by chemical vapor deposition (CVD) were densified by the combined process of chemical vapor infiltration (CVI) and polymer impregnation and Pyrolysis (PIP). The composite exhibited anisotropy depending on the amount of fibers. The maximum tensile strength was more am 500 MPa at room temperature. Two kinds of in situ carbon rich surface layers were formed by fiber-processing. One is ultra-thin 10 nm graphite layer on graded carbon and the other one is graded carbon layer covered with thin silicon oxide. Both of them worked as effective interfaces.

  16. Making use of guava seed (Psidium guajava L): the effects of pre-treatments on its chemical composition.

    PubMed

    Chang, Ying Ping; Tan, May Ping; Lok, Wai Li; Pakianathan, Suganthi; Supramaniam, Yasoga

    2014-03-01

    The guava processing industry in Malaysia produces by-products in the form of seed core and peel. These by-products can be regarded as underused resources but there are concerns about their composition that prevent their use in the food and feed industries. This study aims to analyze the respective effects of heat treatments (boiling or autoclaving) and germination periods on the nutritional composition and phytochemical content of guava seeds. The guava seeds were found to contain 618, 78, 72, and 5 mg/g dry weight total dietary fiber, fat, protein, and ash, respectively. The tannin and saponin contents, but not the phytic acid content, were below the respective anti-nutritional thresholds. The heat treatments did not affect the total dietary fiber and ash contents but reduced all other chemical components to different extents (15-91%). Boiling did not reduce the phytic acid content substantially but autoclaving caused a reduction of 91% to a level below the anti-nutritional threshold. Germination for 14 days caused a significant reduction in nutrient contents in the range of 16-79%. Germination also reduced the phytic acid content by 90% in the seed but did not significantly affect the saponin content. Thus, guava seed can be treated thermally or germinated to manipulate its chemical composition to enable its use in the food and feed industries. PMID:24292972

  17. Permeation of chemical protective clothing by three binary solvent mixtures

    SciTech Connect

    Mickelsen, R.L.; Roder, M.M.; Berardinelli, S.P.

    1986-04-01

    An evaluation of glove materials against three different binary chemical mixtures selected from common industrial solvents was conducted. Changes in breakthrough time and permeation rate of the mixture components were evaluated as a function of the mixture composition. An increase in employee risk resulting from early mixture breakthrough time and enhanced mixture permeation rate over that of the pure chemicals was demonstrated. The permeation of a binary mixture through chemical protective clothing could not be predicted by the permeation results of the pure components. It is recommended that chemical protective clothing be tested for its permeation characteristics with the use of the chemical mixtures and conditions that reflect the work site exposure.

  18. Stressed environmental degradation of automotive composite materials

    SciTech Connect

    Henshaw, J.M.; Meyer, L.J. [Univ. of Tulsa, OK (United States); Houston, D.Q.; Hagerman, E.M.

    1997-12-31

    The degradation of mechanical properties due to exposure to various automotive environments during constant stress or constant strain loading is investigated. Two composites are studied. Each is a polyurethane reinforced with continuous strand E-glass mat, manufactured by the SRIM process. Novel fixtures apply tensile loads to dogbone-specimens while exposed to automotive fluids. After 300 hours, the specimens are tensile tested to failure in air. The effects of five fluids: distilled water, windshield washer fluid, brake fluid, gasoline, and sulfuric acid are examined on the first material. Extensive testing of both materials in distilled water gives a good comparison of the two materials and the effects of loading. Degradation in mechanical properties typically increases with stress level but is independent of the type of loading. This result is discussed in terms of damage and deformation mechanisms in the material.

  19. 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

  20. Advanced composite materials: a strong growth industry

    Microsoft Academic Search

    Lees

    1987-01-01

    Advanced composites represent a material form that will see significant growth in structural applications. The authors notes that Du Pont sees a broad opportunity for these materials and proceeds to review reasons for the company's optimism as well as their approach to this technology. Substitution of composites for metals is shown graphically since 1960 and projected to 2025. Price reductions

  1. Seasonal variation, chemical composition and antioxidant activity of Brazilian propolis samples.

    PubMed

    Teixeira, Erica Weinstein; Message, Dejair; Negri, Giuseppina; Salatino, Antonio; Stringheta, Paulo César

    2010-09-01

    Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin-Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being ?- and ?-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis. PMID:18955317

  2. Seasonal Variation, Chemical Composition and Antioxidant activity of Brazilian Propolis Samples

    PubMed Central

    Teixeira, Érica Weinstein; Message, Dejair; Negri, Giuseppina; Stringheta, Paulo César

    2010-01-01

    Total phenolic contents, antioxidant activity and chemical composition of propolis samples from three localities of Minas Gerais state (southeast Brazil) were determined. Total phenolic contents were determined by the Folin–Ciocalteau method, antioxidant activity was evaluated by DPPH, using BHT as reference, and chemical composition was analyzed by GC/MS. Propolis from Itapecerica and Paula Cândido municipalities were found to have high phenolic contents and pronounced antioxidant activity. From these extracts, 40 substances were identified, among them were simple phenylpropanoids, prenylated phenylpropanoids, sesqui- and diterpenoids. Quantitatively, the main constituent of both samples was allyl-3-prenylcinnamic acid. A sample from Virginópolis municipality had no detectable phenolic substances and contained mainly triterpenoids, the main constituents being ?- and ?-amyrins. Methanolic extracts from Itapecerica and Paula Cândido exhibited pronounced scavenging activity towards DPPH, indistinguishable from BHT activity. However, extracts from Virginópolis sample exhibited no antioxidant activity. Total phenolic substances, GC/MS analyses and antioxidant activity of samples from Itapecerica collected monthly over a period of 1 year revealed considerable variation. No correlation was observed between antioxidant activity and either total phenolic contents or contents of artepillin C and other phenolic substances, as assayed by CG/MS analysis. PMID:18955317

  3. Crystal Structure and Chemical Composition of a Presolar Silicate from the Queen Elizabeth Range 99177 Meteorite

    NASA Technical Reports Server (NTRS)

    Nguyen, A. N.; Keller, L. P.; Rahman, Z.; Messenger, S.

    2013-01-01

    Mineral characterization of presolar silicate grains, the most abundant stardust phase, has provided valuable information about the formation conditions in circumstellar environments and in super-nova (SN) outflows. Spectroscopic observations of dust around evolved stars suggest a majority of amor-phous, Mg-rich olivine grains, but crystalline silicates, most of which are pyroxene, have also been observed [1]. The chemical compositions of hundreds of presolar silicates have been determined by Auger spectroscopy and reveal high Fe contents and nonstoichiometric compositions intermediate to olivine and pyroxene [2-6]. The unexpectedly high Fe contents can partly be attributed to secondary alteration on the meteorite parent bodies, as some grains have Fe isotopic anomalies from their parent stellar source [7]. Only about 35 presolar silicates have been studied for their mineral structures and chemical compositions by transmission electron microscopy (TEM). These grains display a wide range of compositions and structures, including crystalline forsterite, crystalline pyroxene, nanocrystalline grains, and a majority of amorphous nonstoichiometric grains. Most of these grains were identified in the primitive Acfer 094 meteorite. Presolar silicates from this meteorite show a wide range of Fe-contents, suggestive of secondary processing on the meteorite parent body. The CR chondrite QUE 99177 has not suffered as much alteration [8] and displays the highest presolar silicate abundance to date among carbonaceous chondrites [3, 6]. However, no mineralogical studies of presolar silicates from this meteorite have been performed. Here we examine the mineralogy of a presolar silicate from QUE 99177.

  4. A computational study into the (tetrahedral) distortion of TX {sub 2} {alpha}-quartz materials: The effect of changing the chemical composition away from SiO{sub 2}

    SciTech Connect

    Zwijnenburg, Martijn A. [Davy Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS (United Kingdom)]. E-mail: martijn@ri.ac.uk; Huenerbein, Robert [Davy Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS (United Kingdom); Bell, Robert G. [University College London, Department of Chemistry, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Davy Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS (United Kingdom); Cora, Furio [University College London, Department of Chemistry, Christopher Ingold Laboratories, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Davy Faraday Research Laboratory, The Royal Institution of Great Britain, 21 Albemarle Street, London W1S 4BS (United Kingdom)

    2006-11-15

    We report a periodic density functional study into the tetrahedral distortion of a range of quartz-like TX {sub 2} materials. The total tetrahedral distortion and its most sizable contribution, the angular part (angular tetrahedral distortion), are found to be strongly dependent on the chemical composition and to increase in the order of BeF{sub 2}chemical composition. The sulphide materials in the study were found to have tetrahedral distortion values commonly associated in silica with experimentally unrealizable hypothetical frameworks, suggesting that such frameworks might become realizable when stepping away from silica. None of the tetrahedra were found to be strictly regular, in line with the analysis of Smith [Acta. Cryst. 16 (1963) 542-545], demonstrating that regular tetrahedra are in principle possible in quartz but that distortions from ideality are energetically advantageous. The energetic reason for this distortion is still an open question; we propose a simple electrostatic model that explains the ease with which tetrahedra can be distorted in terms of charge transfer and the relative charge on the X (O,S,F) atom. - Graphical Abstract: View on a quartz unit-cell with TX {sub 4} tetrahedra. Display Omitted.

  5. Composite Dielectric Materials for Electrical Switching

    SciTech Connect

    Modine, F.A.

    1999-04-25

    Composites that consist of a dielectric host containing a particulate conductor as a second phase are of interest for electrical switching applications. Such composites are "smart" materials that can function as either voltage or current limiters, and the difference in fimction depends largely upon whether the dielectric is filled to below or above the percolation threshold. It also is possible to combine current and voltage limiting in a single composite to make a "super-smart" material.

  6. Chemical Composition, and Antioxidant and Antimicrobial Activities of Essential Oil of Spearmint (Mentha spicata L.) From Pakistan

    Microsoft Academic Search

    Abdullah I. Hussain; Farooq Anwar; Muhammad Shahid; Muhammad Ashraf; Roman Przybylski

    2010-01-01

    Chemical composition, and antioxidant and antimicrobial activities of the essential oil isolated from aerial parts of Mentha spicata L. (spearmint) were investigated. The oil content was found to be 1.2%. A total of 19 chemical constituents were identified in the spearmint oil using GC and GC\\/MS. The main components were carvone (51.7%) and cis-carveol (24.3%), followed by limonene (5.3%), 1,8

  7. CFRP\\/titanium hybrid material for improving composite bolted joints

    Microsoft Academic Search

    B. Kolesnikov; L. Herbeck; A. Fink

    2008-01-01

    The structural joining remains an essential challenge for the development of composite aerospace structures: every structural interconnection means a disturbance of an optimized structure resulting in an increase in overall structural weight. The lightweight potential of advanced, high-performance fiber composite materials is affected more strongly by mechanical fastening techniques than by conventional metallic materials due to the low shear and

  8. The study of chemical composition and elemental mappings of colored over-glaze porcelain fired in Qing Dynasty by micro-X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Lin, Cheng; Meitian, Li; Youshi, Kim; Changsheng, Fan; Shanghai, Wang; Qiuli, Pan; Zhiguo, Liu; Rongwu, Li

    2011-02-01

    It is very difficult to measure the chemical composition of colored pigments of over-glaze porcelain by X-ray fluorescence because it contains high concentration of Pb. One of the disadvantages of our polycapillary optics is that it has low transmission efficiency to the high energy X-ray. However, it is beneficial to measure the chemical compositions of rich Pb sample. In this paper, we reported the performances of a tabletop setup of micro-X-ray fluorescence system base on slightly focusing polycapillary and its applications for analysis of rich Pb sample. A piece of Chinese ancient over-glaze porcelain was analyzed by micro-X-ray fluorescence. The experimental results showed that the Cu, Fe and Mn are the major color elements. The possibilities of the process of decorative technology were discussed in this paper, also.

  9. Research on Microstructure and Property of TiC-Co Composite Material Made by Laser Cladding

    NASA Astrophysics Data System (ADS)

    Zhang, Wei

    The experiment of laser cladding on the surface of 2Cr13 steel was made. Titanium carbide (TiC) powder and Co-base alloy powder were used as cladding material. The microstructure and property of laser cladding layer were tested. The research showed that laser cladding layer had better properties such as minute crystals, deeper layer, higher hardness and good metallurgical bonding with base metal. The structure of cladding was supersaturated solid solution with dispersed titanium carbide. The average hardness of cladding zone was 660HV0.2. 2Cr13 steel was widely used in the field of turbine blades. Using laser cladding, the good wear layer would greatly increase the useful life of turbine blades.

  10. [Determination of the content of sulfur of coal by the infrared absorption method with high acccuracy].

    PubMed

    Wang, Hai-Feng; Lu, Hai; Li, Jia; Sun, Guo-Hua; Wang, Jun; Dai, Xin-Hua

    2014-02-01

    The present paper reported the differential scanning calorimetry-thermogravimetry curves and the infrared (IR) absorption spectrometry under the temperature program analyzed by the combined simultaneous thermal analysis-IR spectrometer. The gas products of coal were identified by the IR spectrometry. This paper emphasized on the combustion at high temperature-IR absorption method, a convenient and accurate method, which measures the content of sulfur in coal indirectly through the determination of the content of sulfur dioxide in the mixed gas products by IR absorption. It was demonstrated, when the instrument was calibrated by varied pure compounds containing sulfur and certified reference materials (CRMs) for coal, that there was a large deviation in the measured sulfur contents. It indicates that the difference in chemical speciations of sulfur between CRMs and the analyte results in a systematic error. The time-IR absorption curve was utilized to analyze the composition of sulfur at low temperatures and high temperatures and then the sulfur content of coal sample was determined by using a CRM for coal with a close composition of sulfur. Therefore, the systematic error due to the difference in chemical speciations of sulfur between the CRM and analyte was eliminated. On the other hand, in this combustion at high temperature-IR absorption method, the mass of CRM and analyte were adjusted to assure the sulfur mass equal and then the CRM and the analyte were measured alternately. This single-point calibration method reduced the effect of the drift of the IR detector and improved the repeatability of results, compared with the conventional multi-point calibration method using the calibration curves of signal intensity vs sulfur mass. The sulfur content results and their standard deviations of an anthracite coal and a bituminous coal with a low sulfur content determined by this modified method were 0.345% (0.004%) and 0.372% (0.008%), respectively. The uncertainty (U, k =2) of sulfur contents of two coal samples was evaluated to be 0.019% and 0.021%, respectively. Two main modifications, namely the calibration using the coal CRM with a similar composition of low-temperature sulfur and high temperature sulfur, and the single-point calibration alternating CRM and analyte, endow the combustion at high temperature-IR absorption method with an accuracy obviously better than that of the ASTM method. Therefore, this modified method has a well potential in the analysis of sulfur content. PMID:24822403

  11. Composition/bandgap selective dry photochemical etching of semiconductor materials

    DOEpatents

    Ashby, C.I.H.; Dishman, J.L.

    1985-10-11

    Disclosed is a method of selectively photochemically dry etching a first semiconductor material of a given composition and direct bandgap Eg/sub 1/ in the presence of a second semiconductor material of a different composition and direct bandgap Eg/sub 2/, wherein Eg/sub 2/ > Eg/sub 1/, said second semiconductor material substantially not being etched during said method. The method comprises subjecting both materials to the same photon flux and to the same gaseous etchant under conditions where said etchant would be ineffective for chemical etching of either material were the photons not present, said photons being of an energy greater than Eg/sub 1/ but less than Eg/sub 2/, whereby said first semiconductor material is photochemically etched and said second material is substantially not etched.

  12. Chemical Composition of Interstellar Dust: A Monte Carlo Study

    NASA Astrophysics Data System (ADS)

    Das, Ankan; Chakrabarti, Sandip Kumar

    2012-07-01

    Interstellar dust plays a crucial role towards the chemical enrichment of the Interstellar medium. Except the dust chemistry it is impossible to explain the huge abundances of the most abundant species namely molecular hydrogen. Dense cloud is enriched by several molecules which could readily accreted to the dust surface for further chemical enrichment. We performed a Monte Carlo simulation to explore the chemical composition of the dusty grain mantle. It is evident from our simulation that the grain mantle is mainly consists of Water, Methanol Carbon-dioxide and Carbon monoxide. Depending upon the stimulants present around the surrounding atmosphere of the ISM, chemical composition of the grain mantle will change. Around the lower visual extinction region, interstellar photons are seen to play a crucial role (via photo-reactions) for the composition of the dusty grain mantle.

  13. Microbially mediated CH 4 consumption and N 2 O emission is affected by elevated CO 2 , soil water content, and composition of semi-arid grassland species

    Microsoft Academic Search

    Feike A. Dijkstra; Jack A. Morgan; Daniel R. LeCain; Ronald F. Follett

    2010-01-01

    Elevated CO2 affects plant productivity, but also water availability and plant species composition in semi-arid grasslands, thereby potentially\\u000a causing complex effects on CH4 consumption and N2O emission. We studied the effects of atmospheric CO2 concentration (400 vs 780 ?L L?1), water content (15 vs 20% gravimetric soil moisture), and composition of semi-arid grassland species (perennial grasses\\u000a Bouteloua gracilis, Hesperostipa comata, and

  14. Impact of solids on composite materials

    NASA Technical Reports Server (NTRS)

    Bronson, Arturo; Maldonado, Jerry; Chern, Tzong; Martinez, Francisco; Mccord-Medrano, Johnnie; Roschke, Paul N.

    1987-01-01

    The failure modes of composite materials as a result of low velocity impact were investigated by simulating the impact with a finite element analysis. An important facet of the project is the modeling of the impact of a solid onto cylindrical shells composed of composite materials. The model under development will simulate the delamination sustained when a composite material encounters impact from another rigid body. The computer equipment was installed, the computer network tested, and a finite element method model was developed to compare results with known experimental data. The model simulated the impact of a steel rod onto a rotating shaft. Pre-processing programs (GMESH and TANVEL) were developed to generate node and element data for the input into the three dimensional, dynamic finite element analysis code (DYNA3D). The finite element mesh was configured with a fine mesh near the impact zone and a coarser mesh for the impacting rod and the regions surrounding the impacting zone. For the computer simulation, five impacting loads were used to determine the time history of the stresses, the scribed surface areas, and the amount of ridging. The processing time of the computer codes amounted from 1 to 4 days. The calculated surface area were within 6-12 percent, relative error when compated to the actual scratch area.

  15. DISLOCATION MECHANICS ASPECTS OF ENERGETIC MATERIAL COMPOSITES

    Microsoft Academic Search

    R. W. Armstrong

    The dislocation mechanics based properties of solid energetic materials, particularly, of high explosives, are of particular interest in connection with issues of intrinsic chemical stability and with their fast chemical decomposition when employed as propellants or in explosive formulations. The ballistic impact and shock-associated plasticity responses of such materials present great experimental and model challenges for establishment of predictable performances.

  16. Analyzing seed weight, fatty acid composition, oil, and protein contents in Vernonia galamensis germplasm by near-infrared reflectance spectroscopy

    Microsoft Academic Search

    Tesfaye Baye; Heiko C. Becker

    2004-01-01

    Vernonia galamensis is a potential new industrial oilseed crop from the Asteraceae family. The interest in this species is due to the presence\\u000a of a high vernolic acid content of its seed oil, which is useful in the oleochemical industry for paints and coatings. The\\u000a development of a rapid, precise, robust, nondestructive, and economical method to evaluate quality components is

  17. New textile composite materials development, production, application

    NASA Technical Reports Server (NTRS)

    Mikhailov, Petr Y.

    1993-01-01

    New textile composite materials development, production, and application are discussed. Topics covered include: super-high-strength, super-high-modulus fibers, filaments, and materials manufactured on their basis; heat-resistant and nonflammable fibers, filaments, and textile fabrics; fibers and textile fabrics based on fluorocarbon poylmers; antifriction textile fabrics based on polyfen filaments; development of new types of textile combines and composite materials; and carbon filament-based fabrics.

  18. Chemical Composition of Defatted Cottonseed and Soy Meal Products.

    PubMed

    He, Zhongqi; Zhang, Hailin; Olk, Dan C

    2015-01-01

    Chemical composition is critical information for product quality and exploration of new use. Hence defatted cottonseed meals from both glanded (with gossypol) and glandless (without gossypol) cotton seeds were separated into water soluble and insoluble fractions, or water soluble, alkali soluble as well as total protein isolates. The contents of gossypol, total protein and amino acids, fiber and carbohydrates, and selected macro and trace elements in these products were determined and compared with each other and with those of soy meal products. Data reported in this work improved our understanding on the chemical composition of different cottonseed meal products that is helpful for more economical utilization of these products. These data would also provide a basic reference for product standards and quality control when the production of the cottonseed meal products comes to pilot and industrial scales. PMID:26079931

  19. Chemical Composition of Defatted Cottonseed and Soy Meal Products

    PubMed Central

    He, Zhongqi; Zhang, Hailin; Olk, Dan C.

    2015-01-01

    Chemical composition is critical information for product quality and exploration of new use. Hence defatted cottonseed meals from both glanded (with gossypol) and glandless (without gossypol) cotton seeds were separated into water soluble and insoluble fractions, or water soluble, alkali soluble as well as total protein isolates. The contents of gossypol, total protein and amino acids, fiber and carbohydrates, and selected macro and trace elements in these products were determined and compared with each other and with those of soy meal products. Data reported in this work improved our understanding on the chemical composition of different cottonseed meal products that is helpful for more economical utilization of these products. These data would also provide a basic reference for product standards and quality control when the production of the cottonseed meal products comes to pilot and industrial scales. PMID:26079931

  20. Relation of sensory perception with chemical composition of bioprocessed lingonberry.

    PubMed

    Viljanen, Kaarina; Heiniö, Raija-Liisa; Juvonen, Riikka; Kössö, Tuija; Puupponen-Pimiä, Riitta

    2014-08-15

    The impact of bioprocessing on lingonberry flavour was studied by sensory evaluation and chemical analysis (organic acids, mannitol, phenolic compounds, sugars and volatile compounds). Bioprocessing of lingonberries with enzymes, lactic acid bacteria (LAB) or yeast, or their combination (excluding pure LAB fermentation) affected their perceived flavour and chemical composition. Sweetness was associated especially with enzyme treatment but also with enzyme+LAB treatment. Yeast fermentation caused significant changes in volatile aroma compounds and perceived flavour, whereas minor changes were detected in LAB or enzyme-treated berries. Increased concentration of organic acids, ethanol and some phenolic acids correlated with perceived fermented odour/flavour in yeast fermentations, in which increase in benzoic acid level was significant. In enzymatic treatment decreasing anthocyanins correlated well with decreased perceived colour intensity. Enzyme treatment is a potential tool to decrease naturally acidic flavour of lingonberry. Fermentation, especially with yeast, could be an interesting new approach to increase the content of natural preservatives, such as antimicrobial benzoic acid. PMID:24679764

  1. Chemical modifications of renewable cellulosic materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In agriculture, there is a fair amount of byproducts and waste materials. These materials typically contain significant portions of cellulose and hemicellulose. A good opportunity is to take advantage of these relatively cheap renewable materials, carry out chemical reactions, and increase their v...

  2. Composite materials based on wastes of flat glass processing.

    PubMed

    Gorokhovsky, A V; Escalante-Garcia, J I; Gashnikova, G Yu; Nikulina, L P; Artemenko, S E

    2005-01-01

    Glass mirrors scrap and poly (vinyl) butiral waste (PVB) obtained from flat glass processing plants were investigated as raw materials to produce composites. The emphasis was on studying the influence of milled glass mirror waste contents on properties of composites produced with PVB. The characterization involved: elongation under rupture, water absorption, tensile strength and elastic modulus tests. The results showed that the composite containing 10 wt% of filler powder had the best properties among the compositions studied. The influence of the time of exposure in humid atmosphere on the composite properties was investigated. It was found that the admixture of PVB iso-propanol solution to the scrap of glass mirrors during milling provided stabilization of the properties of the composites produced. PMID:16009308

  3. Genetic verification and chemical contents identification of Allamanda species (Apocynaceae).

    PubMed

    Chaveerach, Arunrat; Aungkapattamagul, Sarocha; Tanee, Tawatchai; Noikotr, Kowit; Sudmoon, Runglawan

    2014-05-01

    Allamanda species (Apocynaceae) are popular ornamentals. Additionally, A. cathartica possesses medicinal properties whereas all other species have not been reported. This research aims to analyze genetics and chemical contents of Allamanda species existing in Thailand. The explored species are A. blanchetii, A. cathartica, A. neriifolia, A. schottii, and A. violacea. The dendrogram constructed from 16 inter-simple sequence repeat markers clearly distinguished species with genetic similarity values of 0.92-0.93 for species level and 0.50-0.76 for genus level. Diverse chemicals content in hexane extracts from A. blanchetii, A. neriifolia, A. schottii, and A. violacea were detected by gas chromatography-mass spectrometry. A high amount of squalene was found in A. blanchetii (55.81%) and A. violacea (51.09%). This content may function as a chemo preventative substance to protect people from cancer. ?-Tocopherol, a form of vitamin E, was one of the predominant components found in A. violacea (26.325%), A. schottii (15.41%), and A. neriifolia (9.16%). One more substance, 9,12,15-octadecatrien-1-ol, was found to be relatively high in A. schottii (17.31%) and A. neriifolia (15.51%). Other minor and unknown compounds were also detected. The discovery of these chemicals provides an alternative and supplement for improving human well-being and pharmaceutical industries with natural resources, especially in light of the population increase. PMID:24811796

  4. Characterization and prediction of abrasive wear of powder composite materials

    Microsoft Academic Search

    R. Veinthal; P. Kulu; J. Pirso; H. Käerdi

    2009-01-01

    Composite materials produced by powder metallurgy provide a solution in many engineering applications where materials with high abrasion and erosion resistance are required. The actual wear behaviour of the material is associated with many external factors (particle size, velocity, angularity, etc.) and intrinsic material properties (hardness, toughness, Young modulus, etc.). Hardness and toughness properties of such tribomaterials are highly dependent

  5. Research on damage detection of composite materials based on RBFNN

    Microsoft Academic Search

    Dong Xiaoma; Sun Qingzhen

    2010-01-01

    A dynamic method based on hybrid algorithm RBFNN for damage identification of composite materials was proposed. By using wavelet series, the features of signals were extracted and input to hybrid algorithm RBFNN for training the network and identifying the damages. Finally, the experiment results show that this method can exactly identify the faults of composite materials.

  6. Improved Damage Resistant Composite Materials Incorporating Shape Memory Alloys

    NASA Technical Reports Server (NTRS)

    Paine, Jeffrey S. N.; Rogers, Craig A.

    1996-01-01

    Metallic shape memory alloys (SMA) such as nitinol have unique shape recovery behavior and mechanical properties associated with a material phase change that have been used in a variety of sensing and actuation applications. Recent studies have shown that integrating nitinol-SMA actuators into composite materials increases the composite material's functionality. Hybrid composites of conventional graphite/epoxy or glass/epoxy and nitinol-SMA elements can perform functions in applications where monolithic composites perform inadequately. One such application is the use of hybrid composites to function both in load bearing and armor capacities. While monolithic composites with high strength-to-weight ratios function efficiently as loadbearing structures, because of their brittle nature, impact loading can cause significant catastrophic damage. Initial composite failure modes such as delamination and matrix cracking dissipate some impact energy, but when stress exceeds the composite's ultimate strength, fiber fracture and material perforation become dominant. One of the few methods that has been developed to reduce material perforation is hybridizing polymer matrix composites with tough kevlar or high modulus polyethynylene plies. The tough fibers increase the impact resistance and the stiffer and stronger graphite fibers carry the majority of the load. Similarly, by adding nitinol-SMA elements that absorb impact energy through the stress-induced martensitic phase transformation, the composites' impact perforation resistance can be greatly enhanced. The results of drop-weight and high velocity gas-gun impact testing of various composite materials will be presented. The results demonstrate that hybridizing composites with nitinol-SMA elements significantly increases perforation resistance compared to other traditional toughening elements. Inspection of the composite specimens at various stages of perforation by optical microscope illustrates the mechanisms by which perforation is initiated. Results suggest that the out-of-plane transverse shear properties of the composite and nitinol elements have a significant effect on the perforation resistance. Applications that can utilize the hybrid composites effectively will also be presented with the experimental studies.

  7. Chemical vapor infiltration of TiB[sub 2] composites

    SciTech Connect

    Besmann, T.M.; Miller, J.H.; Cooley, K.C.; Lowden, R.A. (Oak Ridge National Lab., TN (United States)); Starr, T.L. (Georgia Tech Research Inst., Atlanta, GA (United States))

    1993-01-01

    Efficiency of the Hall-Heroult electrolytic reduction of aluminum can be substantially improved by the use of a TiB[sub 2] cathode surface. The use of TiB[sub 2], however, has been hampered by the brittle nature of the material and the grain-boundary attack of sintering-aid phases by molten aluminum. In the current work, TiB[sub 2] is toughened through the use of reinforcing fibers, with chemical vapor infiltration (CVI) used to produce pure TiB[sub 2]. It has been observed, however, that the formation of TiB[sub 2] from chloride precursors at fabrication temperatures below 900 to 1000[degrees]C alloys the retention of destructive levels of chlorine in the material. At higher fabrication temperatures and under appropriate infiltration conditions, as determined from the use of a process model, a TIB[sub 2]THORNEL P-25 fiber composite, 45 mm in diam and 6 mm thick, has been fabricated in 20 h. The material has been demonstrated to be stable in molten aluminum in short-duration tests.

  8. Chemical vapor infiltration of TiB{sub 2} composites

    SciTech Connect

    Besmann, T.M.; Miller, J.H.; Cooley, K.C.; Lowden, R.A. [Oak Ridge National Lab., TN (United States); Starr, T.L. [Georgia Tech Research Inst., Atlanta, GA (United States)

    1993-01-01

    Efficiency of the Hall-Heroult electrolytic reduction of aluminum can be substantially improved by the use of a TiB{sub 2} cathode surface. The use of TiB{sub 2}, however, has been hampered by the brittle nature of the material and the grain-boundary attack of sintering-aid phases by molten aluminum. In the current work, TiB{sub 2} is toughened through the use of reinforcing fibers, with chemical vapor infiltration (CVI) used to produce pure TiB{sub 2}. It has been observed, however, that the formation of TiB{sub 2} from chloride precursors at fabrication temperatures below 900 to 1000{degrees}C alloys the retention of destructive levels of chlorine in the material. At higher fabrication temperatures and under appropriate infiltration conditions, as determined from the use of a process model, a TIB{sub 2}THORNEL P-25 fiber composite, 45 mm in diam and 6 mm thick, has been fabricated in 20 h. The material has been demonstrated to be stable in molten aluminum in short-duration tests.

  9. Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology

    PubMed Central

    Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos

    2015-01-01

    In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level. PMID:25880223

  10. Chemical composition and nutritional value in vitro of mechanically?deboned poultry meat

    Microsoft Academic Search

    M. Duranti; P. Cerletti

    1980-01-01

    1. The composition by proximate analysis, amino acid content and digestibility by mammalian proteolytic enzymes of pastes from mechanically?deboned chicken breasts wings, necks and backs, and hand?deboned breast were measured. Values obtained were used to calculate indices of nutritional value.2. All pastes compared favourably with similar protein materials used for human food. Mechanical deboning did not alter the nutritional indices.3.

  11. Flame-retardant composite materials

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius A.

    1991-01-01

    The properties of eight different graphite composite panels fabricated using four different resin matrices and two types of graphite reinforcement are described. The resin matrices included: VPSP/BMI, a blend of vinylpolystyryl pyridine and bismaleimide; BMI, a bismaleimide; and phenolic and PSP, a polystyryl pyridine. The graphite fiber used was AS-4 in the form of either tape or fabric. The properties of these composites were compared with epoxy composites. It was determined that VPSP/BMI with the graphite tape was the optimum design giving the lowest heat release rate.

  12. Composite material pedestrian bridge for the Port of Bilbao

    NASA Astrophysics Data System (ADS)

    Gorrochategui, I.; Manteca, C.; Yedra, A.; Miguel, R.; del Valle, F. J.

    2012-09-01

    Composite materials in comparison to traditional ones, steel and concrete, present advantages in civil works construction: lower weight, higher corrosion resistance (especially in the marine environment), and ease of installation. On the other hand, fabrication costs are generally higher. This is the reason why this technology is not widely used. This work illustrates the process followed for the design, fabrication and installation of a composite material pedestrian bridge in the Port of Bilbao (Northern Spain). In order to reduce the price of the bridge, the use of low cost materials was considered, therefore polyester resin was selected as the polymeric matrix, and glass fibres as reinforcement. Two material choices were studied. Currently in the market there is high availability of carbon nanoparticles: carbon nanotubes (CNT) and carbon nanofibres (CNF), so it was decided to add this kind of nanoparticles to the reference material with the objective of improving its mechanical properties. The main challenge was to transfer the CNT and CNF excellent properties to the polymeric matrix. This requires dispersing the nanoreinforcements as individual particles in the polymeric matrix to avoid agglomerates. For this reason, an advanced high shear forces dispersion technique (called "three roll mills") was studied and implemented. Also surface functionalization of the nanoreinforcements by chemical treatment was carried out. Herein, a comparison is performed between both materials studied, the explanation of the employment of the reference material (without nanoreinforcement) as the one used in the fabrication of the pedestrian bridge is justified and, finally, the main characteristics of the final design of the structural element are described.

  13. Some functional properties of composite material based on scrap tires

    NASA Astrophysics Data System (ADS)

    Plesuma, Renate; Malers, Laimonis

    2013-09-01

    The utilization of scrap tires still obtains a remarkable importance from the aspect of unloading the environment from non-degradable waste [1]. One of the most prospective ways for scrap tires reuse is a production of composite materials [2] This research must be considered as a continuation of previous investigations [3, 4]. It is devoted to the clarification of some functional properties, which are considered important for the view of practical applications, of the composite material. Some functional properties of the material were investigated, for instance, the compressive stress at different extent of deformation of sample (till 67% of initial thickness) (LVS EN 826) [5] and the resistance to UV radiation (modified method based on LVS EN 14836) [6]. Experiments were realized on the purposefully selected samples. The results were evaluated in the correlation with potential changes of Shore C hardness (Shore scale, ISO 7619-1, ISO 868) [7, 8]. The results showed noticeable resistance of the composite material against the mechanical influence and ultraviolet (UV) radiation. The correlation with the composition of the material, activity of binder, definite technological parameters, and the conditions supported during the production, were determined. It was estimated that selected properties and characteristics of the material are strongly dependent from the composition and technological parameters used in production of the composite material, and from the size of rubber crumb. Obtained results show possibility to attain desirable changes in the composite material properties by changing both the composition and technological parameters of examined material.

  14. Composite materials with uncured epoxy matrix exposed in stratosphere during NASA stratospheric balloon flight

    E-print Network

    Kondyurin, Alexey; Bilek, Marcela

    2010-01-01

    A cassette of uncured composite materials with an epoxy resin matrix was exposed in the stratosphere (40 km altitude) over 3 days. Temperature variations of -76...+32.50C and pressure up to 2.1 Torr were recorded during flight. An analysis of the chemical structure of the composites showed, that the polymer matrix exposed in the stratosphere becomes crosslinked, while the ground control materials react by way of polycondensation reaction of epoxy groups. The space irradiations are considered to be responsible for crosslinking of the uncured polymers exposed in the stratosphere. The composites were cured on Earth after landing. Analysis of the cured composites showed, that the polymer matrix remains active under stratospheric conditions. The results can be used for predicting curing processes of polymer composite in a free space environment during an orbital space flight.

  15. Chemical composition and structural features of the macromolecular components of Hibiscus cannabinus grown in Portugal

    Microsoft Academic Search

    C. Pascoal Neto; A. Seca; D. Fradinho; M. A. Coimbra; F. Domingues; D. Evtuguin; A. Silvestre; J. A. S. Cavaleiro

    1996-01-01

    Different morphological regions of Hibiscus cannabinus plants grown in Portugal were submitted to chemical composition studies. General chemical composition was determined by established methods. The polysaccharides were fractionated by successive extractions of holocellulose with aqueous KOH solutions. The sugar composition was determined by hydrolysis of polysaccharides followed by gas chromatography (GC) analysis of neutral sugars and spectrophotometric determination of uronic

  16. Biodegradable self-reinforced composite materials; manufacturing structure and mechanical properties.

    PubMed

    Törmälä, P

    1992-01-01

    Biodegradable (or absorbable), self-reinforced polymeric composites fulfill the demands of secure orthopaedic fixation materials because of their high strength, appropriate stiffness and strength retention which can be tailored according to the healing rate of damaged tissues. Ultra-high strength, self-reinforced, macroscopical biodegradable polymeric composites can be manufactured by creating the polymeric microstructure, where oriented reinforcing elements and matrix material, which have the same chemical element composition, are bound together. Biodegradable, self-reinforced composites have attractive application possibilities in surgery. The materials can be processed into the form of rods, screws, tacks, cerclages, clamps, plates, spirals, etc., which have versatile applications in traumatology and in orthopaedic surgery. PMID:10149977

  17. Simultaneous synthesis and densification of TiB\\/ ?-Ti(N) composite material by self-propagating combustion under nitrogen pressure

    Microsoft Academic Search

    S. Nakane; O. Yamada; Y. Miyamoto; M. Yoshinaka; K. Hirota; O. Yamaguchi

    1999-01-01

    Simultaneous synthesis and densification of TiB\\/?-Ti(N) composites from Ti (70mol%)\\/ B (30mol%) powder compacts are achieved by self-propagating combustion under a nitrogen pressure of 5MPa. Dense composite materials (97.5% of theoretical) exhibit excellent mechanical properties, in which their fracture toughness and bending strength are 7.8MPam1\\/2 and 640MPa, respectively. Rodlike TiB grains greatly enhance the mechanical properties.

  18. Materials research at Stanford University. [composite materials, crystal structure, acoustics

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Research activity related to the science of materials is described. The following areas are included: elastic and thermal properties of composite materials, acoustic waves and devices, amorphous materials, crystal structure, synthesis of metal-metal bonds, interactions of solids with solutions, electrochemistry, fatigue damage, superconductivity and molecular physics and phase transition kinetics.

  19. Improvement of impact property of natural fiber–polypropylene composite by using natural rubber and EPDM rubber

    Microsoft Academic Search

    Yupaporn Ruksakulpiwat; Jatuporn Sridee; Nitinat Suppakarn; Wimonlak Sutapun

    2009-01-01

    In this research, vetiver grass was used as a filler in polypropylene (PP) composite. Chemical treatment was done to modify fiber surface. Natural rubber (NR) and Ethylene Propylene Diene Monomer (EPDM) rubber at various contents were used as an impact modifier for the composites. The composites were prepared by using an injection molding. Rheological, morphological and mechanical properties of PP

  20. Corrosion inhibiting composition for treating asbestos containing materials

    DOEpatents

    Hartman, Judithann Ruth (Columbia, MD)

    1998-04-21

    A composition for transforming a chrysotile asbestos-containing material into a non-asbestos material is disclosed, wherein the composition comprises water, at least about 30% by weight of an acid component, optionally a source of fluoride ions, and a corrosion inhibiting amount of thiourea, a lower alkylthiourea, a C.sub.8 -C.sub.15 alkylpyridinium halide or mixtures thereof. A method of transforming an asbestos-containing building material, while part of a building structure, into a non-asbestos material by using the present composition also is disclosed.