Note: This page contains sample records for the topic chemical composition by material content from
While these samples are representative of the content of,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of
to obtain the most current and comprehensive results.
Last update: November 12, 2013.

Chemical composition of material fractions in Danish household waste  

Microsoft Academic Search

The chemical composition of Danish household waste was determined by two approaches: a direct method where the chemical composition (61 substances) of 48 material fractions was determined after hand sorting of about 20tonnes of waste collected from 2200 households; and an indirect method where batches of 80–1200tonnes of unsorted household waste was incinerated and the content of the waste determined

Christian Riber; Claus Petersen; Thomas H. Christensen



Development of chemical vapor composites, CVC materials. Final report  

SciTech Connect

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.




Fast, Contactless Monitoring of the Chemical Composition of Raw Materials  

NASA Astrophysics Data System (ADS)

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.

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


Use of radiation effects for a controlled change in the chemical composition and properties of materials by intentional addition or substitution of atoms of a certain kind  

NASA Astrophysics Data System (ADS)

This study is a continuation of works [1-12] dealing with the field developed by the authors, namely, to widen the possibilities of radiation methods for a controlled change in the atomic composition and properties of thin-film materials. The effects under study serve as the basis for the following two methods: selective atom binding and selective atom substitution. Such changes in the atomic composition are induced by irradiation by mixed beams consisting of protons and other ions, the energy of which is sufficient for target atom displacements. The obtained experimental data demonstrate that the changes in the chemical composition of thin-film materials during irradiation by an ion beam of a complex composition take place according to mechanisms that differ radically from the well-known mechanisms controlling the corresponding chemical reactions in these materials. These radical changes are shown to be mainly caused by the accelerated ioninduced atomic displacements in an irradiated material during irradiation; that is, they have a purely radiation nature. The possibilities of the new methods for creating composite structures consisting of regions with a locally changed chemical composition and properties are demonstrated for a wide class of materials.

Gurovich, B. A.; Prikhod'ko, K. E.; Kuleshova, E. A.; Maslakov, K. I.; Komarov, D. A.



Botanical and chemical composition of rumen contents of Sika deer on Mt Goyo, northern Japan  

Microsoft Academic Search

Botanical and chemical compositions of the rumen contents of 58 Sika deer on Mt Goyo, northern Japan, collected from summer\\u000a of 1988 to spring of 1989, were analyzed.Sasa nipponica, a dwarf bamboo, was important in summer (35.0%) and winter (61.4%), but it decreased to 5.6% and was replaced by browse\\u000a leaves in fall, and to 28.0% and was replaced by

Seiki Takatsuki; Shoshichi Ikeda



Chemical Composition  

Microsoft Academic Search

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

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



[The comparative characteristics of chemically and light-hardened composite materials in vitro].  


The strength and color stability of various composites of photo- and chemical consolidation is assessed by laboratory methods. The class of a material is the most essential factor affecting the above characteristics. The macrofilled and hybrid materials showed the best adhesive and bending strength. The method of consolidation does not notably affect the studied characteristics. PMID:10067404

Dedkova, L Iu; Poiurovskaia, I Ia; Peshkina, M G; Chechina, G N



Effect of low frequency vibrations on void content in composite materials  

Microsoft Academic Search

Eliminating common defects such as voids, bubbles, and poor adhesion at interfaces will increase the quality of laminated sandwich composite structure. This work reports experimental research and analysis of the effect of mechanical vibrations applied to the curing system of composite materials production, particularly for minimizing void content. Range of frequency of vibrations covered was from 10 to 50Hz, for

J. Muric-Nesic; P. Compston; N. Noble; Z. H. Stachurski



Composite Materials: Properties as Influenced by Phase Geometry  

Microsoft Academic Search

This book deals with the mechanical and physical behavior of composites as influenced by composite geometry. The monograph provides a comprehensive introduction for researchers and students to modern composite materials research with a special emphasis on the influence of geometry to materials properties. Composite Materials enables the reader to a better understanding of the behavior of natural composites, improvement of

Lauge F. Nielsen



Effect of season on heavy metal contents and chemical compositions of chub mackerel (Scomber japonicus) muscle.  


Seasonal variations of heavy metals concentrations and overall chemical compositions were determined in chub mackerel caught in the Southern Sea of Korea. The average mercury and lead content varied between 0.04 and 0.08 mg/kg and between 0.01 and 0.02 mg/kg, respectively. Seasonal variations were not detected in lead, but mercury displayed maximal values in winter (P < 0.05). A distinct seasonal pattern was found in crude fat content with maximal values in December and minimal values in April. Fatty acid composition showed that monounsaturated fatty acids levels were the highest in August, while polyunsaturated fatty acids (PUFA) levels were the highest in April. The major contributing factors to the seasonal variation of PUFA amounted to 20:5n-3 and 22:6n-3. The total amino acids content varied from 180.6 to 187.7 mg/g. There were no significant seasonal variations in total amounts of amino acids. Practical Application:? Mackerel (Scomber japonicus) is one of the most important fishing resources in Korea. The effects of polyunsaturated fatty acids (PUFA) on the human body have been identified, and consequently, the intake of fish lipids has steadily increased among the human population. There have been few studies on safety and alterations in chemical composition of mackerel attributed to seasonal fluctuations. Therefore, the results presented in this study could be used to improve the safety and nutrition information available to consumers. PMID:22251075

Bae, J H; Lim, S Y



Chemical preparation of manganese dioxide/polypyrrole composites and their use as cathode active materials for rechargeable lithium batteries  

SciTech Connect

Chemical preparation of composite powders of polypyrrole and either {alpha}-MnO{sub 2}, {beta}-MnO{sub 2}, or spinel LiMn{sub 2}O{sub 4} has been successfully achieved by injecting liquid pyrrole into an acidic medium containing suspended manganese dioxide powder as an oxidizing agent. The content of manganese dioxide in the composites increased with increasing amount of suspended manganese dioxide in the polymerization bath. The maximum content of manganese dioxide was 85, 87, and 83.3 weight percent for {alpha}-MnO{sub 2}, {beta}-MnO{sub 2}, and LiMn{sub 2}O{sub 4}, respectively. Charge-discharge tests of {beta}-MnO{sub 2}/polypyrrole and LiMn{sub 2}O{sub 4}/polypyrrole composites conducted in a mixed solvent of propylene carbonate and 1,2-dimethoxyethane (1:1) containing 1 mol/dm{sup 3} LiClO{sub 4} have revealed that the polypyrrole worked well both as an active material and as a conducting network for manganese dioxide. The {beta}-MnO{sub 2}/polypyrrole composite gave one potential plateau in both charge and discharge curves, whereas the LiMn{sub 2}O{sub 4}/polypyrrole composite exhibited two distinct potential regions. The utilization of manganese dioxide was higher when polypyrrole was used as the conducting matrix than when carbon powder was used. Elemental analyses of the composites have revealed that both electrolyte anions and cations were involved in the charge-discharge reaction of the {beta}-MnO{sub 2}/polypyrrole composite, but electrolyte cations alone were involved in that of the LiMn{sub 2}O{sub 4}/polypyrrole composite. The mechanisms of the charge-discharge reaction of these two kinds of composites are in good conformity with the mechanism of composite formation.

Gemeay, A.H.; Nishiyama, Hiroshi; Kuwabata, Susumu; Yoneyama, Hiroshi [Osaka Univ. (Japan). Dept. of Applied Chemistry



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


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

Enrich-Prast, A; Esteves, F A



Study of the compatibility between light-cured repair materials and composite materials by holographic interferometry  

Microsoft Academic Search

Based on current trends in research on techniques for repairing composite materials, this paper focuses on the compatibility between a light-cured repair material and composite materials. The repair material used in this study is intended to find applicability in techniques for repairing damaged composite materials. Test pieces of the composite material were excited by a sinusoidal acoustic source at a

Linfeng Guo; Zhimin Zhao; Mingjuan Gao



Spatial-time variability of particulate material content and its composition: From mesoscale to interannual variability  

NASA Astrophysics Data System (ADS)

The role of the coastal zone in lateral transport and fate of terrestrial organic carbon in the East Siberian Arctic Shelf (ESAS) has not been well studied to date because most recent activities have focused on onshore geomorphologic and geochemical features, while biogeochemical and sedimentation consequences of coastal erosion and riverine runoff into the sea were not studied sufficiently. Here we present the data obtained on joint Russian-US cruises (NOAA and NSF funded) in 2003, 2004, 2005, and in the International Siberian Shelf Study-2008 (ISSS-2008, supported by the Wallenberg Foundation, FEBRAS, NOAA, and the Russian NSF), which characterized a spatial and interannual variability in distribution of particulate material (PM), and its organic carbon and stable isotopes content. Dynamics and composition of PM were studied twice along the Lena River in summer-fall of 2003. Here, the spatial-time dynamics of PM composition (particulate organic carbon (POC), isotopes and mineralogical composition) is considered in connection with changing river runoff and wind patterns. It has been found that the dominant source of POC into the ESAS is coastal erosion, rather than input from the rivers (Lena, Yana, Indigirka, Kolyma). A sharp PM concentration gradient from "freshened/high PM" to "Pacific/low PM" waters was found across the frontal zone. The position of the frontal zone varies significantly from year to year; this difference is mainly attributed to the difference in atmospheric circulation patterns driving the Arctic Ocean circulation. During storms and surges the PM concentration in a single area was increased by 10 times or more (up to 80-242 mg/l) in 2000 and 2005 compared to the 2003 and 2004 PM concentration.

Dudarev, Oleg; Charkin, Alexander; Semiletov, Igor; Gustafsson, Örjan; Vonk, Jorien; Sánchez-García, Laura



Mineral and chemical composition and some trace element contents in coals and coal ashes from Huaibei coal field, China  

Microsoft Academic Search

The mineral and chemical compositions and some trace element contents (As, Ba, Cr, Mn, Mo, Sb, Th, U and V) in coal and coal ash samples from the Huaibei coal field in China were studied. This high volatility bituminous coal has low moisture and S contents, moderate ash yield and high calorific value. The coal ash is abundant in aluminosilicates

Guijian Liu; Stanislav V. Vassilev; Lianfen Gao; Liugen Zheng; Zicheng Peng



Chemical characteristics, fatty acid composition and conjugated linoleic acid (CLA) content of traditional Greek yogurts.  


Many studies with conjugated linoleic acid (CLA) indicate that it has a protective effect against mammary cancer. Because dairy products are the most important dietary sources of CLA, we have investigated the CLA concentrations and additionally the fatty acid profiles and chemical composition of several commercial, traditional, Greek yogurts from different geographical origin. The fat content of yogurts was in the order of goatcontent on lipid basis compared to full-fat yogurts. Samples from mountain areas showed average c-9, t-11 CLA content higher than those from prairie districts. The highest amounts of saturated fatty acids (SFA) were found in low-fat yogurts, of monounsaturated fatty acids (MUFA) in sheep milk yogurts and of polyunsaturated fatty acid (PUFA) in low-fat cow milk yogurts. PMID:23442628

Serafeimidou, Amalia; Zlatanos, Spiros; Laskaridis, Kostas; Sagredos, Angelos



Chemical Composition of Wild2 Dust Collected by Stardust  

Microsoft Academic Search

The Stardust spacecraft collected dust from Comet Wild-2 in two forms: material distributed along tracks in aerogel capture cells and residue in impact craters. To analyze the chemical composition of these samples the tracks produced in the aerogel were extracted as keystones containing complete tracks. Twenty-six tracks were analyzed using an X-Ray Microprobe, providing x-ray fluorescence chemical analysis for elements

G. J. Flynn



Effects of increasing concentrations of corn distillers dried grains with solubles on chemical composition and nutrient content of egg.  


The objective of this study was to determine the effects of feeding high concentrations of corn distillers dried grains with solubles (DDGS) on chemical composition and selected nutrient content of egg yolk. Four isocaloric diets were formulated to contain 0, 17, 35, or 50% corn DDGS. A total of two hundred forty 54-wk-old Single-Comb White Leghorn laying hens were randomly allotted to 2 birds per cage with 3 consecutive cages representing an experimental unit (EU). Each EU was randomly assigned to 1 of 4 dietary treatments according to a completely randomized design. Hens were fed for a 24-wk experimental period after transition feeding to gradually increase corn DDGS inclusion over a 4-wk period. Two sets of experimental diets were formulated to meet or exceed the NRC nutrient recommendations for laying hens. Each diet formula was fed for 12 wk. Chemical composition and nutritional components in egg yolk were measured every 2 wk. The results showed that egg yolk from hens fed a DDGS-containing diet tended to have higher fat content and lower protein content. Total polyunsaturated fatty acids were significantly increased by the DDGS diet. The contents of choline and cholesterol were initially higher in the 50% DDGS treatment group, but were not different in the later period, especially during the last 4 wk. Lutein content increased linearly as DDGS level increased. The results indicated that feeding a high level of DDGS can increase the content of lutein and polyunsaturated fatty acids in egg yolk, but may not affect the content of cholesterol and choline. PMID:23243253

Sun, H; Lee, E J; Samaraweera, H; Persia, M; Ahn, Dong U



Brassica carinata protein isolates: chemical composition, protein characterization and improvement of functional properties by protein hydrolysis  

Microsoft Academic Search

Brassica carinata defatted flour has been used to prepare protein isolates by alkaline extraction and precipitation at low pH. Different extraction parameters have been tested, and the chemical composition and functional properties of the resulting isolates have been analyzed. All the isolates had a protein content above 90% and a well balanced amino acid composition according to FAO standards except

J Pedroche; M. M Yust; H Lqari; J Girón-Calle; M Alaiz; J Vioque; F Millán



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

SciTech Connect

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.

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




Microsoft Academic Search

Production of any type is related with the quality control of all materials involved in technological cycle beginning from dry mix and to final products including intermediate properties. Guaranteed provi- sion of high material properties at all production stages directly effect on their competitiveness. Therefore, in practice the role of analytical monitoring is significantly high. On the basis of modern

S. B. Savvin; N. P. Krivenkova; V. V. Minin; G. M. Kolesov; A. V. Mikhailova



Development of chemical vapor composite (CVC) ceramic materials. Status report, April 1995--June 1997  

SciTech Connect

The objective of the 94 DOE Chemical Vapor Composites (CVC) ceramics materials grant is to develop a reliable and flexible process to produce, in a single step, ceramic composites to final shape. This report is a brief summary of activities in the development of the CVC ceramics materials. Equipment has been designed and built to fabricate CVC silicon carbides with fibers such as Nextel, Nicalon, and carbon. Materials and shapes have been fabricated and characterized as to physical and mechanical properties and microstructure. Details will be given in the final report.




Chemical composition of grape canes  

Microsoft Academic Search

In this study, chemical composition of canes which were sampled from ten different grape cultivars was investigated. For the determination of total phenolics, total flavanols and total flavonol contents, canes were analyzed spectrophotometrically. The phenolic compositions of the canes, including caffeic acid, catechin, p-coumaric acid, epicatechin, gallic acid, luteolin and trans-resveratrol were detected by HPLC. The anthron method was used

Emine Sema Çetin; Duygu Altinöz; Ecehan Tarçan; Nilgün Göktürk Baydar



Chemical composition of camel skim milk concentrated by ultrafiltration  

Microsoft Academic Search

Camel skim milk was concentrated by ultrafiltration (UF) to volume concentration ratios (VCR) of 2, 3, 4 and 5. Gross composition and mineral contents of skim milk and retentates, as well as retention and recovery of components were studied. All fat, CN, WPN, 13–18% of NPN and about 1% of lactose were retained during UF of camel skim milk. Recovery

Mohamed A. Mehaia



Effects of space radiation on a chemically modified graphite-epoxy composite material. Interim report  

SciTech Connect

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.

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



Prediction of the digestibility of primary growth and regrowth grass silages from chemical composition, pepsin-cellulase solubility and indigestible cell wall content  

Microsoft Academic Search

Prediction of organic matter (OM) digestibility (OMD) of primary growth and regrowth grass silages was studied based on their chemical composition, pepsin-cellulase solubility of OM (OMS) and indigestible neutral detergent fibre (INDF) content. Twenty-five primary and 28 regrowth silages were harvested from mixed timothy (Phleum pratense) meadow fescue (Festuca pratensis) or timothy cocksfoot (Dactylis glomerata) swards by varying the dates

J Nousiainen; M Rinne; M Hellämäki; P Huhtanen



Impact of Fe Content in Laboratory-Produced Soot Aerosol on its Composition, Structure, and ThermoChemical Properties  

Microsoft Academic Search

Soot aerosol, which is a major pollutant in the atmosphere of urban areas, often contains not only carbonaceous matter, but also inorganic material. These species, e.g. iron compounds, originated from impurities in fuel or lubricating oil, additives or engine wear may change the physico-chemical characteristics of soot and hence its environmental impact. We studied the change of composition, structure, and

Henrike Bladt; Johannes Schmid; Elena D. Kireeva; Olga B. Popovicheva; Natalia M. Perseantseva; Mikhail A. Timofeev; Katja Heister; Johannes Uihlein; Natalia P. Ivleva; Reinhard Niessner



Composite material  


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.

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



Composite material  

SciTech Connect

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.

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



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

Microsoft Academic Search

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

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



The influence of chemical composition on the properties of Cepheid stars. II. The iron content  

NASA Astrophysics Data System (ADS)

Context: The Cepheid period-luminosity (PL) relation is unquestionably one of the most powerful tools at our disposal for determining the extragalactic distance scale. While significant progress has been made in the past few years towards its understanding and characterization both on the observational and theoretical sides, the debate on the influence that chemical composition may have on the PL relation is still unsettled. Aims: With the aim to assess the influence of the stellar iron content on the PL relation in the V and K bands, we have related the V-band and the K-band residuals from the standard PL relations of Freedman et al. (2001, ApJ, 553, 47) and Persson et al. (2004, AJ, 128, 2239), respectively, to [Fe/H]. Methods: We used direct measurements of the iron abundances of 68 Galactic and Magellanic Cepheids from FEROS and UVES high-resolution and high signal-to-noise spectra. Results: We find a mean iron abundance ([Fe/H]) about solar (? = 0.10) for our Galactic sample (32 stars), ~-0.33 dex (? = 0.13) for the Large Magellanic Cloud (LMC) sample (22 stars) and ~-0.75 dex (? = 0.08) for the Small Magellanic Cloud (SMC) sample (14 stars). Our abundance measurements of the Magellanic Cepheids double the number of stars studied up to now at high resolution. The metallicity affects the V-band Cepheid PL relation and metal-rich Cepheids appear to be systematically fainter than metal-poor ones. These findings depend neither on the adopted distance scale for Galactic Cepheids nor on the adopted LMC distance modulus. Current data do not allow us to reach a firm conclusion concerning the metallicity dependence of the K-band PL relation. The new Galactic distances indicate a small effect, whereas the old ones support a marginal effect. Conclusions: Recent robust estimates of the LMC distance and current results indicate that the Cepheid PL relation is not Universal. Based on observations made with ESO Telescopes at Paranal and La Silla Observatories under proposal ID 66.D-0571. Full Table [see full textsee full textsee full textsee full text] is only available in electronic form at

Romaniello, M.; Primas, F.; Mottini, M.; Pedicelli, S.; Lemasle, B.; Bono, G.; François, P.; Groenewegen, M. A. T.; Laney, C. D.



Modern composite materials manufa- ctured by pressure infiltration method  

Microsoft Academic Search

Purpose: The purpose of this paper is to present the technique of manufacturing the composite materials based on porous ceramic preforms infiltrated by liquid aluminium alloy and examination of the structure and corrosion resistance of those materials. Design\\/methodology\\/approach: The material for investigations was manufactured by pressure infiltration method of ceramic porous preforms. The eutectic aluminium alloy EN AC - AlSi12

L. A. Dobrza?ski; M. Kremzer; M. Drak


TGA-DTA and chemical composition study of raw material of Bikaner region for electrical porcelain  

NASA Astrophysics Data System (ADS)

Porcelains are vitrified and a fine grained ceramic product, used either glazed or unglazed and is often manufactured from a tri-axial body mix of clays, quartz and alkaline feldspar. Physical properties associated with porcelain include those of permeability, high strength, hardness, glassiness, durability, whiteness, translucence, resonance, brittleness, high resistance to the passage of electricity, high resistance to thermal shock and high elasticity[1,2]. Porcelain insulators are made from three raw materials; clay; feldspar and quartz. For porcelain manufacture the clay is categorized in two groups; ball clay and kaolin, each of which plays an important role, either in the preparation of the product or in the properties of the finished products. The following research highlights the importance that suits these materials for their contributions to the final properties of the product. Keeping this view a TGA-DTA and chemical composition of these raw materials were observed and these materials are found suitable for production of Electrical Porcelain.

Tak, S. K.; Shekhawat, M. S.; Mangal, R.



Grained composite materials prepared by combustion synthesis under mechanical pressure  


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.

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



Molecular materials for the transduction of chemical information by CHEMFETs  

Microsoft Academic Search

This paper describes a strategy to overcome the problems associated with the use of MEMFETs as selective chemical sensors. The problems arising from the thermodynamically ill-defined insulator-membrane interface have been eliminated by a new sensor design, viz., the introduction of an intermediate hydrogel layer. Experiments to assess the beneficial effect of such a hydrogel are described. Furthermore, new membrane materials

Jan R. Haak; Wal van der Peter D; David N. Reinhoudt



A new method to quantitatively evaluate the chemical composition of waterlogged wood by means of attenuated total reflectance Fourier transform infrared (ATR FT-IR) measurements carried out on wet material.  


Wood degradation in waterlogged conditions, although slow, is relevant in some specific contexts, such as in the case of cultural heritage preservation (e.g., ancient shipwrecks found under the water table). This decay process induces the selective depletion of the biopolymers constituting wood cell walls and mainly of their structural polysaccharides (both cellulose and hemicelluloses). Assessment of residual composition of cell walls is normally carried out using conventional chemical analyses, which, however, require elevated amounts of material. The present work reports on a new approach to quantitatively determine the residual chemical composition of wood (in terms of amount of lignin and holocellulose) and therefore its extent of degradation. This was accomplished by acquiring attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectra on material still in waterlogged conditions, which was simply placed in optical contact with the ATR crystal. Data for the calibration set were obtained by means of wet analyses, and the calibration model was based on multivariate statistical analysis through partial least square regression. Acquired spectra showed signals higher and better resolved than for dry wood. Calibration was selected after comparing two different normalization procedures and after processing signals of two different spectral ranges. Furthermore, the exclusion of some outliers led to a substantial improvement in the error parameters (R(2) and root mean square error of cross validation) associated with the calibration model, thus allowing for the selection of the best model. The stability of this best model was also established by means of the leave-more-out method. Finally, a procedure of external validation confirmed that the proposed model also could be applied to similar (for instance, belonging to Pinaceae) wood remains from other excavations. PMID:23643045

Pizzo, Benedetto; Pecoraro, Elisa; Macchioni, Nicola



Chemical Controls on Magma Viscosity: Changing Residual Liquid Composition and Volatile Content During Crystallization of Silicic Magmas  

NASA Astrophysics Data System (ADS)

The viscosity of magma exerts a fundamental control over the rates and styles of many geological processes, including melt segregation from source regions, magma ascent rates, magma chamber processes, and style of emplacement or eruption. The combination of magma viscosity and strain rate also determines whether magma will flow or fracture. The viscosity of silicate liquids depends primarily on temperature, liquid composition, and dissolved volatile content, while the viscosity of natural magmas depends also on crystal and bubble content. Here we calculate viscosity changes accompanying crystallization for two case studies: (i) leucogranite magmas of near-minimum melt composition undergo only minor changes in residual liquid composition during crystallization. The viscosity of the magma is then controlled by the physical effect of phenocrysts (increasing viscosity), and increasing volatile content in the liquid phase (decreasing viscosity), over a narrow temperature interval. Magma viscosity may decrease during the early stages of crystallization, especially for low initial volatile contents. (ii) silicic calc-alkaline magmas, crystallizing and fractionating from an initial liquid of andesitic-dacitic composition, and evolving into a crystal-bearing rhyolitic liquid. Under initially water-undersaturated conditions, liquid viscosity can decrease quite dramatically during crystallization, due to increased water content, so that bulk magma viscosity remains nearly constant for crystal contents up to about 40%. Magma viscosity always increases if the liquid is initially water saturated, or if cooling occurs during crystallization, but this increase will be small (? 1 log unit). These case studies demonstrate that it is essential to consider the residual liquid composition, and to apply the mechanical effect of crystals separately, when calculating magma viscosity for modeling many petrologic processes. Failure to do this results in calculated magma viscosities that may be in error by more than an order of magnitude. Furthermore, the role of viscosity in controlling rates of crystal settling and bubble growth, leads to complex feedback relations between magma physics and chemistry.

Whittington, A. G.; Getson, J. M.; Hellwig, B. M.



Chemical composition and energy content of chickens in response to different levels of dietary polyunsaturated fatty acids  

Microsoft Academic Search

Two experiments were performed to study the effect of dietary polyunsaturated fatty acids (PUFA) on abdominal fat pad weight and chemical composition of broilers. In Experiment 1, different fat sources were blended in different ratios keeping added fat level constant (9%). In Experiment 2, PUFA gradient was obtained by increasing the level of inclusion (2, 4, 6 and 8%) of

Cecilia Villaverde; Maria D. Baucells; Lucia Cortinas; Marta Hervera; Ana C. Barroeta



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

SciTech Connect

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.

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



SiC whisker/Si3N4 composites by a chemical mixing process  

SciTech Connect

A chemical mixing process has been developed for making SiC whisker/Si3N4 composites. The process involves in situ synthesis of SiC whiskers in Si3N4 powder by partial carbothermal reduction of silicon nitride in an argon atmosphere. The effects of reaction conditions and starting raw materials on the formation of SiC whiskers were studied. It has been demonstrated that the morphologies of the in situ synthesized whiskers can be modified by varying carbon-source materials and reaction conditions, and the amount of SiC formed in the product can be adjusted by changing the starting Si3N4-to-C ratio. The chemically mixed composite materials were densified by hot pressing with Y2O3 and Al2O3 as sintering aids. 12 refs.

Wang, Hongyu; Fischman, G.S.



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

SciTech Connect

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.

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



Optimum conditions for composites fiber coating by chemical vapor infiltration  

SciTech Connect

A combined analytical and numerical method is employed to optimize process conditions for composites fiber coating by chemical vapor infiltration (CVI). For a first-order deposition reaction, the optimum pressure yielding the maximum deposition rate at a preform center is obtained in closed form and is found to depend only on the activation energy of the deposition reaction, the characteristic pore size, and properties of the reactant and product gases. It does not depend on the preform specific surface area, effective diffusivity or preform thickness, nor on the gas-phase yield of the deposition reaction. Further, this optimum pressure is unaltered by the additional constraint of a prescribed deposition uniformity. Optimum temperatures are obtained using an analytical expression for the optimum value along with numerical solutions to the governing transport equations. These solutions account for both diffusive and advective transport, as well as both ordinary and Knudsen diffusion. Sample calculations are presented for coating preform fibers with boron nitride.

Griffiths, S.K.; Nilson, R.H.



Applicability of prompt gamma-ray analysis to the initial analysis of the extraterrestrial materials for chemical composition  

NASA Astrophysics Data System (ADS)

When extraterrestrial materials are returned to the earth by future space missions, these materials are to be subjected to the initial examination. For such purposes, measurements are desired to be done non-destructively. In this study, we investigated the applicability of non-destructive prompt gamma-ray analysis (PGA) for determining chemical composition of the returned materials, focusing on levels of induced radioactivities and the effect on isotopic composition by PGA. Under current conditions applied for the PGA facility at the Japan Atomic Energy Research Institute, essentially no residual radioactivities remain after appropriate cooling, making the same specimen analyzed by PGA usable for further research without any restriction. The effect on isotopic composition by PGA was examined both for neutron-induced reactions and for neutron-induced nuclear fission of 235U. No significant effect can be brought by neutron-induced reactions even for some noble gas nuclides such as 80Kr and 128I, which can be augmented by (n,g) reactions on neighboring halogens. Neutron-induced nuclear fission reactions of 235U yield essentially no effect on isotopic composition. In addition, PGA has several advantages over other non-destructive analytical methods such as instrumental neutron activation analysis (INAA) and synchrotron radiation x-ray fluorescence (SR-XRF); INAA leaves a significant level of induced-radioactivities and SR-XRF yields less reliable and less accurate values for elemental composition. Judging from these features and characteristics, it is concluded that PGA can be one of the most suitable analytical methods potentially applicable for initial analysis of returned samples from space.

Ebihara, M.; Oura, Y.



Determination of indigestible neutral detergent fibre contents of grasses and its prediction from chemical composition  

Microsoft Academic Search

Five grass species ( Dactylis glomerata L., Phleum pratense L., Lolium perenne L., Festuca arundinacea L. and the hybrid Felina ( Lolium multiflorum L. × Festuca arundinacea L.)), commonly used in roughages for ruminants, were harvested at different maturities of primary growth ( n = 60) and evalu - ated for contents of dry matter (DM), crude protein (CP), ash,

F. Jan?ík; P. Homolka; B. ?ermák; F. Lád



The chemical composition and the content of volatile oil: potential factors that can contribute to the oxidative stability of Nigella sativa L. crude oil.  


The crude oil of Nigella sativa L. (Black cumin) has well-known nutraceutical and pharmaceutical properties. The oil is prone to rapid oxidative deterioration because of its high content of poly-unsaturated fatty acids. In the current investigation, different cold-pressed crude oils of N. sativa were examined for their composition of fatty acids and oxidative stability. The data obtained were correlated with the chemical composition and content of volatile oils, which correspond to each crude oil. Results indicated that different crude oils have the same fatty acid composition, and linoleic acid was the major constituent (60.0-61.7%). Though, the oxidative stability index of the crude oils was different ranging from 2.5 hr to 26.9 hr, as revealed by the Rancimate test at 100°C and airflow rate of 20 ml/min. The results showed that there is a straightforward correlation between the volatile oil content and the oxidative stability of the corresponding parent crude oil. In addition, high ?-terpinene content in the constitution of volatile oil can also be another contributing factor for enhancing the oxidative stability of the crude oil. The data presented here draw attention to some important factors that may guide the nutraceutical and food supplement processors in their screening for the highest quality of Nigella crude oils with maximum health benefits. PMID:22432633

Edris, Amr E



The Strawberry ( Arbutus unedo L.) fruits: Chemical composition, physical properties and mineral contents  

Microsoft Academic Search

Nutrition and physical properties were established in developing Arbutus unedo L. Fruits from Mersin (Lapa-Gülnar) to investigate potential uses. Completely maturated fruits ash, crude oil, crude energy, crude fiber, crude protein, water soluble extract, ether-soluble extract, alcohol-soluble extract, dimethyl sulfite (DMS), essential oil content and minerals including K, P, Ca, Na and Fe. Also, physical properties such as length, mass,

Mehmet Musa Özcan; Haydar Hac?sefero?ullar?



Recycling By Solvolysis Thermosetting Composite Materials Of Sustainable Surface Transport  

NASA Astrophysics Data System (ADS)

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° 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° C lead us to make a parallel with osmosis phenomena to explain the initiation mechanism of the degradation.

Oliveux, Géraldine; Le Gal La Salle, Eric; Bailleul, Jean-Luc



Recycling By Solvolysis Thermosetting Composite Materials Of Sustainable Surface Transport  

SciTech Connect

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.

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)



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

SciTech Connect

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.

Lee, W.Y.



[Effect of processing on the chemical contents and hepatic and renal toxicity of rhubarb studied by canonical correlation analysis].  


In this article, canonical correlation analysis was used to explore the relationship between the toxicity-attenuating effect and the variation of chemical contents in rhubarb caused by processing. With quasi-acute toxicity test, the difference of hepatic and renal toxicity to mice with the processed materials of rhubarb was researched. The chemical contents of anthraquinones and tannins in rhubarb were measured by UV-vis spectrophotometry and high performance liquid chromatography. The results showed that there were toxic effects to liver and kidney in mice after repeated intragastric administration of rhubarb and its processed materials for 14 days at a dosage of 76 g x kg(-1). The toxic effect of processed materials was much lower than crude drug. With canonical correlation analysis, the sequence of the hepatic and renal toxicity of chemical contents in rhubarb were found as follows: total anthraquinone glycosides (AQGs) > tannins (Tns) > total anthraquinones (AQs); aloe-emodin (AE) > physcione (Ph) > rhein (Rn) > emodin (Ed) > chrysophanol (Ch) and AEG > PhG > ChG > EdG > RnG of glycosyl-anthraquinone. It could be concluded that processing would attenuate the toxicity of crude drug of rhubarb. The toxicity-attenuating effect might be correlated to the decline of the contents of both anthraquinone glycosides and tannins, especially the aloe-emodin glycoside and physcione glycoside. The results also suggested that the serum alanine aminotransferase (ALT) and creatine (CREA) would be useful to monitor the hepatic and renal toxicity of rhubarb. PMID:20055157

Wang, Jia-Bo; Ma, Yong-Gang; Zhang, Ping; Jin, Cheng; Sun, Yu-Qi; Xiao, Xiao-He; Zhao, Yan-Ling; Zhou, Can-Ping



Composited BCN/carbon fibers prepared by hot-filament chemical vapor deposition  

NASA Astrophysics Data System (ADS)

The combined BCN/carbon fibers with porous configuration have been successfully prepared by hot-filament chemical vapor deposition (HF-CVD). The composited materials consist of carbon fiber inside covered by the cylindrical BCN films. The differences in the surface morphology and the diameter of the composite fibers are related to the different reactant gases. It is demonstrated that the elements of B, C, and N are chemically bonded with atomic-level BCN hybrid in the composite fibers. The resistance of the composite fibers is about 300 ? which is 10 times higher than that of the isolated carbon fibers (27.5 ?). When the applying voltage increases up to 8-15 V, the BCN films have been broken down and the resistance of composite fibers decreases to the typical value of the carbon fibers. The composite fibers with porous configuration have the strongly capacity to adsorb oxygen. The findings suggest that the combined BCN/carbon fibers are favorable for achieving high performance nano-optoelectronic and sensor devices.

Lü, Jiannan; Li, Hongdong; Zhu, Pinwen; Lü, Xianyi; Li, Yingai



Self-healing structural composite materials  

Microsoft Academic Search

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

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



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

NASA Astrophysics Data System (ADS)

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 the fibers and crack-filling with adhesives that behave more rigidly when bonded inside cracks. An investigation was made into the development of smart cement composites that can self-repair internal cracks due to mechanical loading. The research focused on the cracking of hollow repair fibers dispersed in a composite and the resulting timed release of chemicals that seal matrix microcracks and rebond any damaged interfaces between fiber and matrix. Fiber pull-out tests were performed to examine rebonding of fibers. The rebonding was successful.

Dry, Carolyn M.



Chemical composition and vasodilatation induced by Cuphea carthagenensis preparations.  


The aerial parts of Cuphea carthagenensis (Jacq.) J.F. Macbride (Lythraceae) are traditionally employed in Brazil to treat cardiovascular diseases. The aim of this study was to compare preparations of C. carthagenensis aerial parts (aqueous and ethanol extracts, together with derived fractions) with regard to their total phenolic contents and in vitro vasodilating activity. The main flavonoids found in the extracts were isolated and identified as quercetin derivatives. The extracts and fractions showed similar HPLC profiles with the presence of quercetin-5-O-?-glucopyranoside, quercetin-3-O-?-arabinofuranoside and quercetin-3-sulfate in all of them, but marked differences in the contents of flavonoids, proanthocyanidins, tannis and total phenolics. Excepting the aqueous extract, all assayed preparations elicited vasodilatation on pre-contracted rat aortic rings in the range of pIC(50) 4.53±0.03 to 4.98±0.06. Polynomial regression analysis demonstrated the relationship between vasodilating activity and the contents of flavonoids (r(2)=0.5190), proanthocyanidins (r(2)=0.8016), tannins (r(2)=0.8041) and total phenolics (r(2)=0.6226), suggesting the participation of these compounds in the pharmacological effect and their potential use as chemical markers for the species. PMID:22739415

Krepsky, Patricia Baier; Isidório, Raquel Geralda; de Souza Filho, José Dias; Côrtes, Steyner França; Braga, Fernão Castro



Innovative processing of porous and cellular materials by chemical reaction  

Microsoft Academic Search

Nickel aluminide foam and porous Ti composite (TiC,TiB(2)\\/Ti) were synthesized. A reaction between Ni and Al was used to make the nickel aluminide foam. Porous Ti composite was fabricated by reactions between (1) Ti and C or (2) Ti and B4C. Gas release from the elemental powders and initial porosity in the green powder compact were the formation mechanisms of

N. Kanetake; M. Kobashi



Activated carbon fibers with a high heteroatom content by chemical activation of PBO with phosphoric acid.  


The preparation of activated carbon fibers (ACFs) by phosphoric acid activation of poly(p-phenylene benzobisoxazole) (PBO) fibers was studied, with particular attention to the effects of impregnation ratio and carbonization temperature on porous texture. Phosphoric acid has a strong effect on PBO degradation, lowering the temperature range at which the decomposition takes place and changing the number of mass loss steps. Chemical analysis results indicated that activation with phosphoric acid increases the concentration of oxygenated surface groups; the resulting materials also exhibiting high nitrogen content. ACFs are obtained with extremely high yields; they have well-developed porosity restricted to the micropore and narrow mesopore range and with a significant concentration of phosphorus incorporated homogeneously in the form of functional groups. An increase in the impregnation ratio leads to increases in both pore volume and pore size, maximum values of surface area (1250 m(2)/g) and total pore volume (0.67 cm(3)/g) being attained at the highest impregnation ratio (210 wt % H(3)PO(4)) and lowest activation temperature (650 °C) used; the corresponding yield was as large as 83 wt %. The obtained surface areas and pore volumes were higher than those achieved in previous works by physical activation with CO(2) of PBO chars. PMID:22401268

Vázquez-Santos, M B; Suárez-García, F; Martínez-Alonso, A; Tascón, J M D



The wettability of carbon/TiB2 composite materials by aluminum in cryolite melts  

NASA Astrophysics Data System (ADS)

Both pure TiB2 and carbon/TiB2 composites are potential cathode materials for aluminum reduction cells. An important requirement for this application is that the material be wetted by aluminum in cryolite melts. A sessile drop technique combined with X-ray radiography was used to measure the contact angle formed between aluminum and pure hot-pressed TiB2, carbon/TiB2 composite, graphite, and a carbonaceous cement in cryolite melts. Pure hot-pressed TiB2 was found to be completely wetted by aluminum in cryolite melts. Graphite and the carbonaceous cement were nonwetted by aluminum in cryolite melts, the contact angles being in the range of 144 to 158 deg. The contact angle formed by aluminum on the carbon/TiB2 composite in cryolite melts exhibited time dependency. It was proposed the time dependency was due to (1) removal of contamination from the composite surface and (2) removal of aluminum from the drop. The wettability of the composite material increased as the TiB2 content increased.

Watson, K. D.; Toguri, J. M.



Assimilation of trace elements by the mussel Mytilus edulis : effects of diatom chemical composition  

Microsoft Academic Search

Mussels have been widely used as bioindicators of coastal contamination, and recent reports have demonstrated that metals are accumulated from both the dissolved phase and from ingested food. In the winter and spring of 1995, we examined the influence of the chemical composition of food (protein content, trace element concentrations and ratios in the diatom Thalassiosira pseudomana) on the assimilation

Wang Wen-Xiong; N. S. Fisher



Fabrication of Composite Material Using Gettou Fiber by Injection Molding  

NASA Astrophysics Data System (ADS)

This study investigated the mechanical properties of composite using gettou (shell ginger) fiber as reinforcement fabricated from injection molding. Gettou fiber is a natural fiber made from gettou, a subtropical plant that is largely abundant in Okinawa, Japan. We used the stem part of gettou plant and made the gettou fiber by crushing the stem. The composite using gettou fiber contributed to low shrinkage ratio, high bending strength and high flexural modulus. The mechanical strength of composite using long gettou fiber showed higher value than composite using short gettou fiber. Next, because gettou is particularly known for its anti-mold characteristic, we investigated the characteristic in gettou plastic composite. The composite was tested against two molds: aspergillius niger and penicillium funiculosum. The 60% gettou fiber plastic composite was found to satisfy the JISZ2801 criterion. Finally, in order to predict the flexural modulus of composite using gettou fiber by Halpin-Tsai equation, the tensile elastic modulus of single gettou fiber was measured. The tendency of the experimental results of composite using gettou fiber was in good agreement with Halpin-Tsai equation.

Setsuda, Roy; Fukumoto, Isao; Kanda, Yasuyuki



Microsoft Academic Search

PurposeChoice of efficacious clinical management of symptomatic renal calculi can be facilitated by ascertaining the precise chemical composition of the calculus. Spiral computerized tomography (CT) is becoming a frequently used radiographic examination to establish the diagnosis and severity of calculus disease. Our objective for this study was to determine the precision of spiral CT in identifying the chemical composition of




A review of laser machining of composites and the chemical by-product formed by such processes  

NASA Astrophysics Data System (ADS)

The laser-cutting of polymers and polymer-based composites is reviewed with emphasis placed on the chemical by-products formed by such processes. It has been reported that toxic and potentially carcinogenic materials are formed; therefore, appropriate control measures need to be incorporated into the engineering design of laser-cutting facilities to maintain air quality of the workplace within the guidelines established by governmental regulatory agencies.

Doyle, Daryl J.


Regulating continent growth and composition by chemical weathering  

USGS Publications Warehouse

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. ?? 2008 by The National Academy of Sciences of the USA.

Lee, C. -T. A.; Morton, D. M.; Little, M. G.; Kistler, R.; Horodyskyj, U. N.; Leeman, W. P.; Agranier, A.



Topochemistry, Porosity and Chemical Composition Affecting Enzymatic Hydrolysis of Lignocellulosic Materials  

Microsoft Academic Search

\\u000a Lignocellulosic materials such as sugarcane bagasse represent a lowcost source of carbon for biofuel and chemical production,\\u000a including cellulosic ethanol. Despite its low cost and availability, bagasse presents several technical challenges for its\\u000a conversion to monomeric sugars suitable for fermentation processes. It is highly recalcitrant, which requires efficient pretreatment\\u000a for enzymatic hydrolysis. Both pretreatment and enzymatic hydrolysis have frequently been

Adriane M. F. Milagres; Walter Carvalho; Andre Ferraz


Regulating continent growth and composition by chemical weathering.  


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

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



Regulating continent growth and composition by chemical weathering  

Microsoft Academic Search

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

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



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

Microsoft Academic Search

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

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


Determining Pu isotopic composition and Pu content of PuBe sources by neutron coincidence technique  

Microsoft Academic Search

The paper describes a pure neutron method for determining both Pu content and Pu isotopic composition of PuBe neutron sources by neutron coincidence technique, without using gamma-spectrometry. The new procedure based on the R\\/T–T relationship is a developed version of the R\\/T-method based on R\\/T–MPu calibration curve described in [C.T. Nguyen, J. Bagi, L. Lakosi, A novel method of quantitative

Cong Tam Nguyen; Janos Bagi; Laszlo Lakosi



Material Removal By Chemical Mechanical Polishing-A Review  

NASA Astrophysics Data System (ADS)

Polishing, the most expensive machining processes, in terms time and labor costs depending on the required surface finish, optic size, and amount of surface roughness from preceding machining operations. A material could remain on the polishing system for hours to days. Thus, attempting to understand the underlying mechanisms and basic science associated with the polishing process is crucial to, in turn, develop methods and procedures to reduce cost, trim schedule, and bolster performance. With an increased need for low surface roughness optics, as in x-ray and enhanced ultra-violet applications, it is imperative to understand the impacts of changing system variables. This paper reviews mechanism of chemical-mechanical polishing (CMP),to provide some interlinking data that can be used to many fundamental aspects of the CMP mechanism ,in turn can predict process responses, e.g., material removal rate, non-uniformity across the wafer, dielectric erosion and metal dishing. This review will provide a new platform for further investigation in CMP mechanism of material removal.

Sivanandini, M.; Dhami, S. S.; Pabla, B. S.



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

SciTech Connect

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.

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



Influence of the chemical composition on the machinability of brasses  

Microsoft Academic Search

Although brasses are essentially copper and zinc alloys, they also contain other alloying elements such as lead, silicon, aluminium, iron, tin, manganese, nickel or arsenic whose presence and content are responsible for the wide variety of properties inherent to these materials.In this article, the effect of the chemical composition of brasses, considering each alloying element and the effective copper content,

C. Vilarinho; J. P. Davim; D. Soares; F. Castro; J. Barbosa



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.


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

NASA Astrophysics Data System (ADS)

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.

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



Synthesis of copper\\/chromium oxide composites by a chemical processing method  

Microsoft Academic Search

The aim of this paper is to synthesize a copper\\/chromium oxide composite material. The use of a chemical processing method\\u000a like the Pechini method is the best approach to control the chemistry and the microstructure. Nevertheless, the standard Pechini\\u000a method has to be modified to obtain this specific type of composite. In this work, we have adapted two steps. Firstly

Amélie Veillère; Jean-François Silvain; Joël Douin; Michel Lahaye; Namas Chandra; Jean-Marc Heintz



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...


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...


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

Microsoft Academic Search

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

Andrea Versari; Giuseppina Paola Parpinello; Sergio Galassi



Chemical composition and biological value of spray dried porcine blood by-products and bone protein hydrolysate for young chickens  

Microsoft Academic Search

1. The chemical composition of spray dried porcine blood by-products is characterised by wide variation in crude protein contents. In spray dried porcine blood plasma (SDBP) it varied between 670–780?g\\/kg, in spray dried blood cells (SDBC) between 830–930?g\\/kg, and in bone protein hydrolysate (BPH) in a range of 740–780?g\\/kg. Compared with fish meal, these feeds are poor in Met and

D. Jamroz; A. Wiliczkiewicz; J. Orda; J. Skorupi?ska; M. S?upczy?ska; J. Kuryszko



Composite Structural Materials.  

National Technical Information Service (NTIS)

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 perf...

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



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

Microsoft Academic Search

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

Thammarat Kaewmanee; Soottawat Benjakul; Wonnop Visessanguan



Permeation of glove materials by physiologically harmful chemicals  

Microsoft Academic Search

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




Study on the chemical composition features of Longquan celadon excavated from the Chuzhou site of Huai'an City in Jiangsu Province by EDXRF  

NASA Astrophysics Data System (ADS)

A mass of Longquan celadon shards were excavated from the Chuzhou site of Huai'an City in Jiangsu Province, China. These celadon shards were fired during the period of the Late Yuan Dynasty to the Tianshun era of the Ming Dynasty, as identified by archaeologists at Nanjing Museum. In order to research the chemical composition features of this ancient celadon porcelain, energy dispersive X-ray fluorescence (EDXRF) for non-destructive analysis was used to determine the chemical composition of the porcelain body and glaze in these shards. The results indicate that Ti and Fe in the body of Longquan celadon are characteristic elements which can distinguish porcelain produced during the Late Yuan Dynasty from those produced in the Ming Dynasties. The results of the principal component analysis (PCA) show that different body and glaze raw materials were used for the production of porcelain in different periods and the raw materials of the body and glaze are also different for various vessel shapes. The chemical compositions in the porcelain body of civilian ware are slightly different. The imperial and civilian Longquan celadon porcelains produced during the Hongwu era to the Tianshun era of the Ming Dynasty are distinguishable by the MnO, Fe2O3, Rb2O and SrO content in their porcelain glaze.

Li, Li; Feng, Song-Lin; Feng, Xiang-Qian; Xu, Qing; Yan, Ling-Tong; Ma, Bo; Huo, Hua



Histopathology of Human Coronary Atherosclerosis by Quantifying Its Chemical Composition With Raman Spectroscopy  

Microsoft Academic Search

Background—Lesion composition, rather than size or volume, determines whether an atherosclerotic plaque will progress, regress, or rupture, but current techniques cannot provide precise quantitative information about lesion composition. We have developed a technique to assess the pathological state of human coronary artery samples by quantifying their chemical composition with near-infrared Raman spectroscopy. Methods and Results—Coronary artery samples (n5165) obtained from

Tjeerd J. Romer; James F. Brennan III; Maryann Fitzmaurice; Michael L. Feldstein; Geurt Deinum; Jonathan L. Myles; John R. Kramer; Robert S. Lees; Michael S. Feld


Studies on acid oils and fatty acids for chickens III. Effect of chemical composition on metabolisable energy of by-products of vegetable oil refining.  


1. Fourteen by-products of oil refining, selected for their variability in free fatty acid and unsaponifiable contents, were analysed chemically with the objective of relating the determined ME values of the products to chemical composition by means of multiple linear regression analysis. Refined sunflower oil was included as a reference fat. 2. Twenty-one 2-week-old chicks were used to determine fat digestibilities and AMEn values of diets, using the total collection method. Fats were included in a wheat-soyabean meal diet at 100 g/kg. Multiple linear regression analysis was used to express the ME values of fats as functions of the parameters measured (moisture, gross energy, impurities, unsaponifiables, non eluted material, free fatty acid content, unsaturated: saturated ratio, peroxide value, TBA test). 3. The ME of the fat products lay in the range l2.62 to 24.35 MJ/kg, and 29.26 MJ/kg for refined sunflower oil. Free fatty acid content of the fats was shown to be a poor predictor of their ME values, whereas non eluted material (NEM) of the fat products showed a good correlation with their ME. A regression equation could be derived (R2 0.6548; SEE 2.0064) with the unsaturated: saturated ratio (U:S) and NEM. An ME prediction equation based on the U:S, NEM and unsaponifiable content is also proposed (R2= 0.7l68; SEE= 1.9058). PMID:8833534

Vila, B; Esteve-Garcia, E



Physico-chemical properties of low density polyethylene and ethylene vinyl acetate composites cross-linked by ionizing radiation  

NASA Astrophysics Data System (ADS)

Conductive polymers consisting of low density polyethylene (LDPE), ethylene vinyl acetate copolymer (EVA) and carbon black (CB) were prepared by melt mixing. LDPE/CB, EVA/CB and LDPE/EVA/CB composites were irradiated by electron beam over the range 50-200 kGy. The effect of CB content, CB type, content of the EVA and irradiation dose on the physico-chemical properties (gel content, volume resistivity, mechanical and thermal properties) was investigated. The gel content increased as a function of both increasing irradiation dose and CB content, and a significant improvement in the mechanical properties (tensile strength and elongation at break) was observed. By increasing the CB content, the volume resistivity dropped by several orders of magnitude. Thermogravimetric analysis parameters including onset temperature (Ti, °C), differential thermogravimetric peak temperature (DTG, °C) and temperatures at 50% and 95% weight losses were investigated. Thermal stability of the conductive composites was enhanced by addition of either CB or EVA and the degree of enhancement was correlated to their contents. The melt flow index decreased with incorporation of CB leading to more viscous matrix.

Basfar, A. A.; Ali, Z. I.



Chemical Composition of Polymer Surfaces Imaged by Atomic Force Microscopy and Complementary Approaches  

Microsoft Academic Search

In this article we review the recent developments in the field of high resolution lateral mapping\\u000a of the surface chemical composition of polymers by atomic force microscopy (AFM) and other complementary\\u000a imaging techniques. The different AFM approaches toward nanometer scale mapping with chemical sensitivity\\u000a based on chemical force microscopy (CFM) are discussed as a means to unravel, for instance, the\\u000a lateral

G. Julius Vancso; Henrik Hillborg; Holger Schönherr



Lipid content and composition of coffee brews prepared by different methods.  


The lipid content and composition of boiled, filtered, dripped, Turkish and espresso coffees prepared from roasted beans of Coffea arabica and Coffea robusta, and of coffees prepared from different brands of instant coffee were examined. The lipid content varied with the method of preparation. While coffee brews filtered through filter paper contained less than 7 mg lipids, those prepared by boiling without filtering and espresso coffee reached 60-160 mg lipids/150-ml cup. Coffee brew filtered through a metal screener contained 50 mg lipids/150-ml cup. Although the lipid content varied, the method of preparation of the brew and filtration had no important influence on the lipid composition. During paper filtration lipids remained mainly in spent coffee grounds, and the brew and filter paper retained only 0.4 and 9.4%, respectively, of the total lipids recovered. However, the lipids in the brew, filter paper and spent coffee grounds had the same profile, indicating that there was no preferential retention of a particular lipid component in filter paper. Triglycerides and diterpene alcohol esters were the major lipid classes in coffee brewed from ground coffee beans, and ranged from 86.6 to 92.9 and 6.5 to 12.5% of total lipids, respectively. For coffee brews made from instant coffee, the levels of these two lipid classes were 96.4-98.5 and 1.6-3.6%, respectively. The lipid contents of both regular and decaffeinated instant coffees varied slightly from one brand to the other, and ranged from 1.8 to 6.6 mg/150-ml cup. PMID:8477916

Ratnayake, W M; Hollywood, R; O'Grady, E; Stavric, B



Nondestructive evaluation of composite materials by electrical resistance measurement  

NASA Astrophysics Data System (ADS)

This dissertation investigates electrical resistance measurement for nondestructive evaluation of carbon fiber (CF) reinforced polymer matrix composites. The method involves measuring the DC electrical resistance in either the longitudinal or through thickness direction. The thermal history and thermal properties of thermoplastic/CF composites were studied by longitudinal and through-thickness resistance measurements. The resistance results were consistent with differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) results. The resistance measurements gave more information on the melting of the polymer matrix than TMA. They were more sensitive to the glass transition of the polymer matrix than DSC. The through-thickness resistance decreased as autohesion progressed. The activation energy of autohesion was 21.2 kJ/mol for both nylon-6 and polyphenylene sulfide (PPS)/CF composites. Adhesive bonding and debonding were monitored in real-time by measurement of the through-thickness resistance between the adherends in an adhesive joint during heating and subsequent cooling. Debonding occurred during cooling when the pressure or temperature during prior bonding was not sufficiently high. A long heating time below the melting temperature (T m) was found to be detrimental to subsequent PPS adhesive joint development above Tm, due to curing reactions below Tm and consequent reduced mass flow response above Tm. A high heating rate (small heating time) enhanced the bonding more than a high pressure. The longitudinal resistance measurement was used to investigate the effects of temperature and stress on the interface between a concrete substrate and its epoxy/CF composite retrofit. The resistance of the retrofit was increased by bond degradation, whether the degradation was due to heat or stress. The degradation was reversible. Irreversible disturbance in the fiber arrangement occurred slightly as thermal or load cycling occurred, as indicated by the resistance decreasing cycle by cycle. This dissertation also addresses the use of the electrical resistance method to observe thermal and mechanical damage in real time. A temperature increase caused the interlaminar contact resistance to decrease reversibly within each thermal cycle, while thermal damage caused the resistance to decrease abruptly and irreversibly, due to matrix molecular movement and the consequent increase in the chance of fibers of one lamina touching those of an adjacent lamina. The through-thickness volume resistivity irreversibly and gradually decreased upon mechanical damage, which was probably fiber-matrix debonding. Moreover, it reversibly and abruptly increased upon matrix micro-structural change, which occurred reversibly near the peak stress of a stress cycle.

Mei, Zhen


Mechanics of composite materials  

SciTech Connect

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.

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))



Synthesis and characterization of SiC-reinforced silicon composites produced by chemical vapor deposition  

SciTech Connect

The goal of this study was to prepare SiC-reinforced silicon matrix composites. Chemical vapor deposition techniques were employed to deposit Si onto the surface of SiC fibers and to infiltrate silicon carbide fibers to form a cylindrical composite. A mixture of SiCl{sub 4} and H{sub 2} was reacted at 1,000{degree}C to produce the Si coating. The morphology of Si deposition was monitored by scanning electron microscopy. The structural properties of the composite were studied by powder x-ray diffraction methods. Surface studies of the composites were investigated with x-ray photoelectron spectroscopy.

Hwan, L.; Willis, W.S.; Suib, S.L. (Univ. of Connecticut, Storrs (USA)); Galasso, F. (United Technologies Research Center, Hartford, CT (USA))



Chemical Fractionation in Chondrites by Aerodynamic Sorting of Chondritic Materials  

Microsoft Academic Search

Aerodynamic sorting in the nebula has been invoked directly or indirectly to account for the size variations of chondrules in different groups [1], associated size variations of chondrules and metal spherules in a CR chondrite [2], and variations in the oxygen isotopic compositions of H-L-LL chondrules and whole rocks [3]. We suggest that aerodynamic sorting processes affected the relative abundances

E. R. D. Scott; H. Haack



Improved pinning properties in Y123 materials by chemical substitutions.  

SciTech Connect

We have investigated how T{sub c}, J{sub c} and B{sub irr} of compounds with double CuO{sub 2} planes depend on the physical properties and structural features of the blocking layer. By comparing J{sub c} and B{sub irr} for several families of HTSC we have concluded that the intrinsic flux pinning is controlled to a large extent by the conductivity of the blocking layer. The width of the intermediate region between the blocks of the double CuO{sub 2} planes is less significant. To modify the conductivity of the CuO chains and decrease the anisotropy of the YBa{sub 2}Cu{sub 3}O{sub y} compound, substitutions of transition elements for Cu and Sr for Ba were done resulting in enhanced pinning properties and increased T{sub c} of YBaSrCu{sub 3-x}Mo{sub x}O{sub y} from 81 K for x=0 to 86 K for x=0.05-0.1. The pinning characteristics of substituted material were significantly modified most likely by a formation of dimers of corner shared MoO{sub 6} octahedra. The same structural modification was used to improve the pinning properties of the YBa{sub 2}Cu{sub 3}O{sub y} compound.

Rogacki, K.; Dabrowski, B.; Chmaissem, O.; Jorgensen, J. D.; Materials Science Division; Illinois Inst. of Tech.; Science Univ. of Tokyo; Naval Research Lab.



Determination of the fibre volume content in natural fibre-reinforced composites by ultimate analysis  

Microsoft Academic Search

Natural fibre-reinforced plastics (NFRP) with renewable polymers as matrices are expected to be an increasing market in the\\u000a future. In this context the quantification of natural fibre volume content in composites is an important parameter for manufacturers\\u000a to check the laminate quality. This paper reports a new time and cost efficient method for the determination of natural fibre\\u000a volume content

T. Mahrholz; U. Riedel



Unsupervised content discovery in composite audio  

Microsoft Academic Search

Automatically extracting semantic content from audio streams can be helpful in many multimedia applications. Motivated by the known limitations of traditional supervised approaches to content extraction, which are hard to generalize and require suitable training data, we propose in this paper an unsupervised approach to discover and categorize semantic content in a composite audio stream. In our approach, we first

Rui Cai; Lie Lu; Alan Hanjalic



Chemical Composition of Ultra-High Energy Cosmic Rays Observed by AGASA  

NASA Astrophysics Data System (ADS)

We have observed ultra-high energy cosmic rays above the Greisen-ZatsepinKuz'min cut-off energy by Akeno Giant Air Shower Array. Their chemical composition is a key discriminator of origin models. In the present work, we estimate the average composition by an analysis of muons in air showers with AIRES+QGSJET simulation. The data matches the prediction for light hadron primaries and no indication has been found for a gamma-ray dominance.

Shinozaki, K.; Chikawa, M.; Fukushima, M.; Hayashida, N.; Honda, K.; Inoue, N.; Kadota, K.; Kakimoto, F.; Kamata, K.; Kawaguchi, S.; Kawakami, S.; Kawasaki, Y.; Kawasumi, N.; Mase, K.; Mizobuchi, S.; Nagano, M.; Ohoka, H.; Osone, S.; Sakaki, N.; Sakurai, N.; Sasaki, M.; Sasano, M.; Shimizu, H. M.; Takeda, M.; Teshima, M.; Torii, R.; Tsushima, I.; Uchihori, Y.; Yamamoto, T.; Yoshida, S.; Yoshii, H.



Biotechnology and Composite Materials.  

National Technical Information Service (NTIS)

Biotechnology, in general terms, is the science and engineering of using living organisms for making useful products such as pharmaceuticals, foods, fuels, chemicals, materials or in waste treatment processes and clinical and chemical analyses. It encompa...

B. C. Woolsey R. Narayan R.C. Schiavone



Investigation of the Composition of Tuyere Coke by Analyzing the Surface Material Removed by Abrasion.  

National Technical Information Service (NTIS)

The nature of the surface of the tuyere cokes was examined by subjecting them to size reduction in a flightless drum. The ash, iron and alkali contents of the degradation products were measured to estimate the degree of deposition of these materials betwe...



Active metal-matrix composites with embedded smart materials by ultrasonic additive manufacturing  

NASA Astrophysics Data System (ADS)

This paper presents the development of active aluminum-matrix composites manufactured by Ultrasonic Additive Manufacturing (UAM), an emerging rapid prototyping process based on ultrasonic metal welding. Composites created through this process experience temperatures as low as 25 °C during fabrication, in contrast to current metal-matrix fabrication processes which require temperatures of 500 °C and above. UAM thus provides unprecedented opportunities to develop adaptive structures with seamlessly embedded smart materials and electronic components without degrading the properties that make these materials and components attractive. This research focuses on developing UAM composites with aluminum matrices and embedded shape memory NiTi, magnetostrictive Galfenol, and electroactive PVDF phases. The research on these composites will focus on: (i) electrical insulation between NiTi and Al phases for strain sensors, investigation and modeling of NiTi-Al composites as tunable stiffness materials and thermally invariant structures based on the shape memory effect; (ii) process development and composite testing for Galfenol-Al composites; and (iii) development of PVDF-Al composites for embedded sensing applications. We demonstrate a method to electrically insulate embedded materials from the UAM matrix, the ability create composites containing up to 22.3% NiTi, and their resulting dimensional stability and thermal actuation characteristics. Also demonstrated is Galfenol-Al composite magnetic actuation of up to 54 ?(see manuscript), and creation of a PVDF-Al composite sensor.

Hahnlen, Ryan; Dapino, Marcelo J.



Chemical composition of patikaraparpam.  


Patikaraparpam, a Siddha formulation in prepared by trituration of potash alum with egg albumin followed by calcinatin. The three authentic laboratories made parpams as well as six commercial samples have been examined for their chemical composition. The analytical data that emerged from the analysis of the above samples showed that seven parpams contained only aluminium sulphate and they did respond to tests for potassium. An inspection of the crude drugs patikaram' available in the market established that potash alum and ammonia alum are indiscriminateldy taken for use, according to literature, only potash alum should be used in Indian system of medicine. Patikarapparapam is indicated in urinary inflammations and obstructions and is a reputed diuretic. Potassium salts are established diuretic. These studies show that the raw drugs sellers, the pharamaceutists or manufacturers of medicine and the physician as well should make sure that only potash alum is used in Indian medicine. PMID:22556804

Saraswathy, A; Rani, M G; Susan, T; Purushothaman, K K



Seasonal Variability and Chemical Composition of Carbon Export by the Yukon River, Alaska  

NASA Astrophysics Data System (ADS)

The flow and chemical composition of Arctic rivers are highly variable and reflect the mix of sources and flow paths of surface and ground water contributing to them during any particular season. Annual Yukon River carbon (C) export is dominated by the spring flush, with more than 50% of organic C and 30% of inorganic C exports occurring during May and June. As part of the US National Science Foundation's Arctic Great Rivers Observatory Project, which is studying the six largest rivers discharging to the Arctic Ocean, we measured Yukon River flow and water chemistry at high frequency during the critical periods immediately preceding, during, and following ice melt in 2009 - 2011. Springtime flows had high dissolved organic carbon (DOC) concentrations that rose quickly with water discharge at ice out and decreased with flow into summer. Waters collected near peak flow had high specific ultraviolet absorbance (SUVA) values and high aromatic C content. The rising limb of the spring flush hydrograph also had the greatest bioavailable DOC (BDOC) content, relative to the remainder of the year. The bulk of the DOC exported in spring was of terrestrial plant origin and 14C modern, with respiration carbon dioxide collected from BDOC incubations having similar 14C content to that of the bulk DOC. Interestingly, FT-ICR MS characterization of the DOC exported during the spring flush indicated the presence of labile, atmospherically deposited DOC components having apparent fossil fuel combustion origin, similar to those identified in direct glacial runoff. The importance of the spring flush period and of DOC exports to the total C budget of the Yukon River will also be discussed in the context of seasonal patterns of water discharge, watershed C yields, and of dissolved, particulate, and gaseous inorganic and organic C concentration and flux.

Striegl, R.; Aiken, G.; Butman, D.; Dornblaser, M.; Raymond, P.; Schuster, P.; Spencer, R.; Stubbins, A.; Wickland, K.



Effect of binder content on the material properties of polymethyl methacrylate fabricated by three dimensional printing technique  

Microsoft Academic Search

This study reports the development of polymethyl methacrylate-based mixture which is suitable for direct freeform fabrication by three dimensional printing (3DP) technique. The influence of different compositions on formability, physical and mechanical properties of fabricated 3DP samples was studied. It was found that binder content in the composition should be greater than 10% for successful fabrication of polymethyl methacrylate samples

P. Patirupanusara; W. Suwanpreuk; T. Rubkumintara; J. Suwanprateeb



Predicting the chemical composition and structure of Aspergillus nidulans hyphal wall surface by atomic force microscopy  

Microsoft Academic Search

In fungi, cell wall plays an important role in growth and development. Major macromolecular constituents of the aspergilli\\u000a cell wall are glucan, chitin, and protein. We examined the chemical composition and structure of the Aspergillus nidulans hyphal wall surface by an atomic force microscope (AFM). To determine the composition of the cell wall surface, the adhesion\\u000a forces of commercially available

Hyun-uk Lee; Jong Bae Park; Haeseong Lee; Keon-Sang Chae; Dong-Min Han; Kwang-Yeop Jahng



Effect of Paint Removal by Natural Bead Blasting on the Surface Morphology of Composite Materials.  

National Technical Information Service (NTIS)

The purpose of the study was to investigate paint removal by blasting and its effects on the surface morphology of the composite materials. Plastic media blasting (PMB), used extensively by many as a paint removal method, showed potential microstructural ...

T. H. Guy H. Lankarani J. E. Talia



Cynara cardunculus L.: chemical composition and soda-anthraquinone cooking  

Microsoft Academic Search

This paper presents results about the determination of chemical composition of a new annual plant (Cynara cardunculus L. or Cardoon in English) growing in Portugal at experimental scale. Two raw materials were studied. The first one concerns over mature crops collected in 1996, whereas the second one was collected at the right time in 1997. The Klason lignin content of

A. Antunes; E. Amaral; M. N. Belgacem



Chemical composition, fatty acid content and antioxidant potential of meat from goats supplemented with Moringa (Moringa oleifera) leaves, sunflower cake and grass hay.  


The present study determined the chemical composition, fatty acid (FA) content and antioxidant capacity of meat from goats supplemented with Moringa oleifera leaves (MOL) or sunflower cake (SC) or grass hay (GH). The meat from goat supplemented with MOL had higher concentrations of total phenolic content (10.62±0.27 mg tannic acid equivalent E/g). The MOL significantly scavenged 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic-acid (ABTS) radical to 93.51±0.19% (93.51±0.19%) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical to 58.95±0.3% than other supplements. The antioxidative effect of MOL supplemented meat on catalase (CAT), reduced glutathione (GSH), superoxide dismutase (SOD) and lipid oxidation (LO) was significantly (P<0.05) higher than other meat from goat feed on grass hay or those supplemented with sunflower seed cake. The present study indicated that the anti-oxidative potential of MOL may play a role in improving meat quality (chemical composition, colour and lipid stability). PMID:23273450

Qwele, K; Hugo, A; Oyedemi, S O; Moyo, B; Masika, P J; Muchenje, V



Chemical Composition of Martian Rocks  

NASA Astrophysics Data System (ADS)

In situ analyses of martian surface rocks (and soils) provided data about the chemical composition of several landing sites. One of the used techniques is the alpha-induced x-ray emission applied by the Alpha Particle X-Ray Spectrometer (APXS) onboard the current Mars Exploration Rovers (MER) Spirit and Opportunity and onboard the preceding Mars Pathfinder Rover Sojourner (MPF Mission). These measurements encompass the determination of major, minor, and (for the MER APXS) trace elements, such as Ni, Zn, and Br, as well as Cu, Pb, Sr, Y, Ga, and Ge. The obtained data indicate a remarkable compositional difference between the rocks at the different landing sites, whereas most soils including those measured by the Viking landers are chemically similar. Initially, the only chemical data of Mars were obtained by the study of a class of meteorites that turned out to be martian, which was furthermore confirmed by the discovery of a rock (by rover Opportunity) that is chemically related to those meteorites. The rocks at the Pathfinder landing site turned out to be richer in Si and K than the martian meteorites and all rocks encountered at the MER sites. At Gusev crater (the first MER landing site), two geological regions were encountered along the rover Spirit's traverse: the plains and the hills. Rocks in the plains resemble primitive basalts, while rocks located in the Columbia Hills revealed different types. Several rock classes could be cataloged based on their chemical composition. Most of the hills rocks are significantly weathered and enriched in mobile elements, such as P, Zn, S, Cl, and Br. On the other hand, a suite of ultramafic rocks was discovered for the first time on Mars. The rocks at Meridiani Planum (the second MER landing site) are salt-rich siliciclastic sediments. All rocks showed much higher S contents than the soils. High concentrations of Cl and Br were also discovered at various samples. Huge quantities of spherules were found on top of soils and outcrops along the rover's traverse. APXS measurements revealed that these spherules contain high amounts of iron that is mainly present as the mineral hematite (determined by Mössbauer spectrometry). The formation of hematite is typically, but not exclusively, an indicator for aqueous activities under oxidizing conditions. The in situ measurements at both MER landing sites point to a variety of sedimentary processes and various types of alteration processes; hence, they show clear evidence of ancient aqueous environments that discontinued long time, ago. The combination of in situ measurements and element correlations obtained by the martian meteorites implies an ancient basaltic crust with high abundances of incompatible elements (K, Rb, Nd, U, and Th) and volatile elements (S, Cl). Compared to the Earth's mantle, the martian mantle contains about twice as much Fe, is richer in moderately volatile elements like K, and has a much higher abundance of phosphorus. In conjunction with chemical data obtained from orbit, such as gamma-ray spectrometry carried out by the Mars Odyssey spacecraft, a global estimation of the composition of the martian surface is obtained and, furthermore, crustal composition can be derived.

Brueckner, J.



Chemical Composition of Mish \\  

Microsoft Academic Search

This study was conducted to evaluate the chemical composition of mish during storage. Ninety samples of mish were collected on the day of manufacture (day one) from three different dairy plants (DP1, DP2, DP3), transported to the laboratory of the Department of Dairy Production, Faculty of Animal Production in ice box and stored at 7 C for 28 days. Samples

Mohamed Osman Mohamed Abdalla; Somaia Zonnoon; Abdel Nabi Ahmed



Quantitative Chemical Analysis Online Materials  

NSDL National Science Digital Library

This is a site with materials related to a chemistry textbook. It is not as general as some sites but the material is of high pedagogical value. Short tutorial sections are available for many topics with extensive web linkages. "Living" graphs and Excel files illustrate important material such as pH fractional composition and statistical analysis. Students can take practice quizzes on material from the text. Full Powerpoint slideshows include nearly all of the figures contained in the text. A full set of laboratory experiments are available. Users must register to view much of the site's content; registration is free.

Harris, Daniel C., 1948-



Retention of organic and inorganic chemicals by the drainage\\/supply piping material  

Microsoft Academic Search

A critical issue facing the turfgrass industry is the environmental fate and transport of organic and inorganic chemicals used on golf courses. The fate and distribution of those chemicals are strongly influenced by sorptive interactions with soil and sediment. In this study, the drainage and water supply piping material (used for construction of a prototype encapsulated golf green) was utilized

Kun Li; W. A. Torello; Baoshan Xing



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

Microsoft Academic Search

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

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



Coprecipitated, copper-based, alumina-stabilized materials for carbon dioxide capture by chemical looping combustion.  


Chemical looping combustion (CLC) has emerged as a carbon dioxide capture and storage (CCS) process to produce a pure stream of CO(2) at very low costs when compared with alternative CCS technologies, such as scrubbing with amines. From a thermodynamic point of view, copper oxide is arguably the most promising candidate for the oxygen carrier owing to its exothermic reduction and oxidation reactions and high oxygen-carrying capacity. However, the low melting point of pure copper of only 1085 °C has so far prohibited the synthesis of copper-rich oxygen carriers. This paper is concerned with the development of copper-based and Al(2)O(3)-stabilized oxygen carriers that contain a high mass fraction of CuO, namely, 82.4 wt %. The oxygen carriers were synthesized by using a coprecipitation technique. The synthesized oxygen carriers were characterized in detail with regards to their morphological properties, chemical composition, and surface topography. It was found that both the precipitating agent and the pH at which the precipitation was performed strongly influenced the structure and chemical composition of the oxygen carriers. In addition, XRD analysis confirmed that, for the majority of the precipitation conditions investigated, CuO reacted with Al(2)O(3) to form fully reducible CuAl(2)O(4). The redox characteristics of the synthesized materials were evaluated at 800 °C by using methane as the fuel and air for reoxidation. It was found that the oxygen-carrying capacity of the synthesized oxygen carriers was strongly influenced by both the precipitating agent and the pH at which the precipitation was performed; however, all oxygen carriers tested showed a stable cyclic oxygen-carrying capacity. The oxygen carriers synthesized at pH 5.5 using NaOH or Na(2)CO(3) as the precipitating agents were the best oxygen carriers synthesized owing to their high and stable oxygen transfer and uncoupling capacities. The excellent redox characteristics of the best oxygen carrier were interpreted in light of the detailed morphological characterization of the synthesized material and a synthesis-structure-performance relationship was developed. PMID:22744876

Imtiaz, Qasim; Kierzkowska, Agnieszka Marta; Müller, Christoph Rüdiger



Contact acoustic nonlinearity phenomenon caused by the acoustic wave propagating in the composite material  

Microsoft Academic Search

Due to the massive applications of multilayered composite materials (for example carbon fiber material, glass fiber material etc.) in material industry, aviation industry, medical enterprise and other consumer industries, it becomes an important work to carry on the non-destructive evaluation to the long-term characteristic and the security of the composite materials in use. The reliability of a composite material is

Jian-jun Chen; De Zhang; Yi-wei Mao



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

Microsoft Academic Search

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

Walter Kaminsky



Influence of Bulk Chemical Composition on Relative Sensitivity Factors for 55Mn/52Cr by SIMS: Implications for the 53Mn-53Cr Chronometer  

NASA Astrophysics Data System (ADS)

The 53Mn-53Cr systematics of meteorite samples provide an important high resolution chronometer for early solar system events. Accurate determination of the initial abundance of 53Mn (? 1/2=3.7 Ma) by secondary ion mass spectrometry (SIMS) is dependent on properly correcting for differing ion yields between Mn and Cr by use of a relative sensitivity factor (RSF). Ideal standards for SIMS analysis should be compositionally and structurally similar to the sample of interest. However, previously published Mn-Cr studies rely on few standards (e.g., San Carlos olivine, NIST 610 glass) despite significant variations in chemical composition. We investigate a potential correlation between RSF and bulk chemical composition by determining RSFs for 55Mn/52Cr in 11 silicate glass and mineral standards (San Carlos olivine, Mainz glasses KL2-G, ML3B-G, StHs6/80-G, GOR128-G, BM90/21-G, and T1-G, NIST 610 glass, and three LLNL pyroxene-composition glasses). All standards were measured on the Cameca ims-3f ion microprobe at LLNL, and a subset were also measured on the Cameca ims-1270 ion microprobe at the Geological Survey of Japan. The standards cover a range of bulk chemical compositions with SiO2 contents of 40-71 wt.%, FeO contents of 0.05-20 wt.% and Mn/Cr ratios between 0.4 and 58. We obtained RSF values ranging from 0.83 to 1.15. The data obtained on the ims-1270 ion microprobe are within ~10% of the RSF values obtained on the ims-3f ion microprobe, and the RSF determined for San Carlos olivine (0.86) is in good agreement with previously published data. The typical approach to calculating an RSF from multiple standard measurements involves making a linear fit to measured 55Mn/52Cr versus true 55Mn/52Cr. This approach may be satisfactory for materials of similar composition, but fails when compositions vary significantly. This is best illustrated by the ~30% change in RSF we see between glasses with similar Mn/Cr ratios but variable Fe and Na content. We are developing an approach that uses multivariate analysis to evaluate the importance of different chemical components in controlling the RSF and predict the RSF of unknowns when standards of appropriate composition are not available. Our analysis suggests that Fe, Si, and Na are key compositional factors in these silicate standards. The RSF is positively correlated with Fe and Si and negatively correlated with Na. Work is currently underway to extend this analysis to a wider range of chemical compositions and to evaluate the variability of RSF on measurements obtained by NanoSIMS.

Matzel, J.; Jacobsen, B.; Hutcheon, I. D.; Kita, N.; Ryerson, F. J.



Determination of the mechanical indices of composite materials by testing multilayered samples  

Microsoft Academic Search

The mechanical indices of materials such as composites reinforced by braids and ribbons are difficult to determine by standard methods. Moreover, the indices of such materials may be greatly altered when they are converted into various structures. It has been suggested that these indices be determined by analyzing the structure testing data. The determination of linear and nonlinear elastic, plastic,

I. G. Teregulov; R. A. Kayumov; Yu. I. Butenko; D. Kh. Safiullin



Electrically conductive composite material  


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.

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



Composite Material Switches  

NASA Astrophysics Data System (ADS)

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.

Javadi, Hamid



Chemical composition and energy content of deep-sea calanoid copepods in the Western North Pacific Ocean  

Microsoft Academic Search

Condition factor index [CFI=1000×DW\\/(PL)3; DW: dry weight, PL: prosome length], water content, carbon (C), nitrogen (N), ash and energy content were determined on a total of 69 copepod species caught from the mesopelagic (500–1000m), upper-bathypelagic (1000–2000m), lower-bathypelagic (2000–3000m) and abyssopelagic (3000–5000m) zones of the western subarctic Pacific. Resultant data were grouped into these four sampling zones, four developmental stage\\/sex categories

Tsutomu Ikeda; Atsushi Yamaguchi; Takashi Matsuishi



40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection...Subpart Z of Part 98âDefault Chemical Composition of Phosphate Rock by Origin Origin Total carbon(percent by weight)...



Synthesis of nanostructured carbon materials by open-air laser-induced chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Elemental carbon in the sp2 hybridization state can form a great variety of graphitic and amorphous structures. Carbon nanotube is a well-known form of graphitic carbon that has remarkable mechanical, electronic and electrochemical properties with applications ranging from reinforced composite materials to micro-scale electronic devices. Pyrolytic carbon film with turbostratic structure is a form of amorphous carbon that possesses excellent barrier properties against diffusion of moisture and hydrogen, and is used as hermetic coating for optical fibers operating under harsh environments. Current deposition techniques for these novel carbon materials are limited in production rate, quality and reproducibility, thereby restricting their usage for advanced applications. In this dissertation, an open-air laser-induced chemical vapor deposition technique is proposed and investigated for the rapid growth of high quality carbon nanotubes and nanometer thick pyrolytic carbon films. The first part of the thesis focuses on the open-air synthesis of carbon nanotubes on stationary and moving fused quartz substrates. The second part will study the deposition of pyrolytic carbon film on various optical components including optical fibers. Optical microscopy, high-resolution transmission and scanning electron microscopy, Raman and Auger electron spectroscopy, as well as x-ray energy-dispersive spectrometry, scanning white-light interferometry and thermal pyrometry are used to investigate the deposition rate, morphology, microstructure and chemical composition of the deposited carbon materials.

Kwok, Kinghong


Chemical composition and structural phase changes of Pd sample and properties of novel synthesized structure at dense deuterium gas under irradiation by ?-quanta  

NASA Astrophysics Data System (ADS)

Studies have been carried out into the element composition of Pd and brass with associated materials and synthesized novel structure, placed in dense deuterium gas in a deuterium high-pressure chamber (DHPC) under the pressure 3 kbar and irradiated with ?-quanta of energy up to 8.8 MeV. Using the methods of scanning electron microscopy, microelement chemical analysis and X-ray diffraction, it was determined that in the absence in the chamber volume and walls of all HPC-forming materials the synthesized structure is largely composed of alumosilicates and Al and Si oxides with high content of Ti compounds as rutile TiO2. Pd1.5D2. Considerable anomalies in the chemical composition were found both in the surface and at large depth in a Pd specimen. The entire Pd surface turned into a structure comprised of Pd clusters, Cu and Zn compounds, with a notable content of Mg, Al, S, Si, K, Ca, Ti and Fe compounds. Results of evaluative calculations, including computation of the Q-value, are presented for nuclear reactions produced in a saturated with deuterium Pd specimen and dense deuterium gas under the action of ?-quanta, neutrons and protons of energies up to E n + E p ? E ? - E D MeV generated by deuteron fission. The obtained results can be explained by "collective effects" as chain reactions caused by deuteron fission induced by protons ( E p > 3.39 MeV) and neutrons ( E n > 2.25 MeV), as well as by thermonuclear synthesis of deuterium atoms elastically scattered by protons of energies up to E P < E ? - E D MeV.

Didyk, A. Yu.; Wi?niewski, R.



Terahertz scattering by granular composite materials: An effective medium theory  

NASA Astrophysics Data System (ADS)

Terahertz (THz) spectroscopy and imaging have emerged as important tools for identification and classification of various substances, which exhibit absorption characteristics at distinct frequencies in the THz range. The spectral fingerprints can potentially be distorted or obscured by electromagnetic scattering caused by the granular nature of some substances. In this paper, we present THz time domain transmission measurements of granular polyethylene powders in order to investigate an effective medium theory that yields a parameterized model, which can be used to estimate the empirical measurements to good accuracy.

Kaushik, Mayank; Ng, Brian W.-H.; Fischer, Bernd M.; Abbott, Derek



Chemical Composition of the Essential Oils of Achillea millefolium L. Isolated by Different Distillation Methods  

Microsoft Academic Search

The chemical composition of the essential oil from flowering tops of Achillea millefolium L. isolated by different distillation methods was studied. Samples were hydrodistilled with Clevenger-type (HD), simultaneous micro-distillation-extraction (SMDE), and microwave (MAHD) apparatus. The yields were 0.46% ± 0.03 for the HD and 0.48% ± 0.03 for the MAHD (v\\/w, volume\\/dry weight). The oils were analyzed by GC and

Carlo I. G. Tuberoso; Adam Kowalczyk



Effect of fruit ripening on content and chemical composition of oil from three oil palm cultivars (Elaeis guineensis Jacq.) grown in Colombia.  


A series of physical and chemical changes occur as oil palm fruits ripen in the bunch. We evaluated changes in lipid content in the mesocarp and fruits, and the chemical composition of fatty acids (FA), triacylglycerol (TAG), tocols, and carotenes of the lipids extracted from fruits of three commercial tenera cultivars, namely, Deli×La Me?, Deli×Ekona, and Deli×Avros, planted in two different geographical regions in Colombia, during the ripening process 12, 14, 16, 18, 20, 22, and 24 weeks after anthesis (WAA). It was found that 12 WAA the mesocarp contained less than 6% of total lipids. Oil content increased rapidly after 16 WAA, reaching the maximum oil content of 55% in fresh mesocarp and 47% in fresh fruits at 22 WAA, which was found the optimal time for harvesting. Changes in FA and TAG showed that total polyunsaturated fatty acids (PUFA) and triunsaturated triacylglycerols (TUTAG) decreased, while total saturated fatty acids (SFA) and disaturated triacylglycerols (DSTAG) increased, over the ripening period. Changes in FA were mainly observed in palmitic, oleic, linoleic, and linolenic acids, and in POP, POO, POL, and OLL for the TAGs evaluated. Levels of tocols changed depending on whether they were tocopherols or tocotrienols. In the earliest stages tocopherols were predominant but decreased rapidly from 6600 mg kg(-1) of oil at 14 WAA to 93 mg kg(-1) of oil at 22 WAA. Tocotrienols appeared at the same time as oil synthesis started, and became the main source of total tocols, equivalent to 87% in total lipids extracted. PMID:21894914

Prada, Fausto; Ayala-Diaz, Iván M; Delgado, Wilman; Ruiz-Romero, Rodrigo; Romero, Hernán M



Proximate composition and caloric content of eight Lake Michigan fishes  

USGS Publications Warehouse

We measured the proximate composition (percentage lipid, water, fat-free dry material, ash) and caloric content of eight species of Lake Michigan fish: lake trout (Salvelinus namaycush), coho salmon (Oncorhynchus kisutch), lake whitefish (Coregonus clupeaformis), bloater (Coregonus hoyi), alewife (Alosa pseudoharengus), rainbow smelt (Osmerus mordax), deepwater sculpin (Myoxocephalus quadricornis), and slimy sculpin (Cottus cognatus). Except for alewives, proximate composition and caloric content did not differ significantly between males and females. And, for coho salmon, there was no significant difference in composition between fish collected in different years. Lipid and caloric content of lake trout increased directly with age. In all species examined, lipids and caloric contents were significantly lower in small, presumably immature, fish than in larger, older fish. Lipid content of lake trout, lake whitefish, and bloaters (range of means, 16-22%) was nearly 3 times higher than that of coho salmon, sculpins, rainbow smelt, and alewives (range of means, 5.2-7.0%). The mean caloric content ranged from 6.9 to 7.1 kcal/g for species high in lipids and from 5.8 to 6.3 kcal/g for species low in lipids. Although the caloric content of all species varied directly with lipid content and inversely with water content, an increase in lipid content did not always coincide with a proportional increase in caloric content when other components of fish composition were essentially unchanged. This observation suggests that the energy content of fish estimated from the proximate composition by using universal conversion factors may not necessarily be accurate.

Rottiers, Donald V.; Tucker, Robert M.



Resin composite restorative materials.  


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

Ilie, N; Hickel, R



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

SciTech Connect

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.

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



The Chemical Composition of Honey  

ERIC Educational Resources Information Center

|Honey is a supersaturated sugar solution, created by bees, and used by human beings as a sweetener. However, honey is more than just a supersaturated sugar solution; it also contains acids, minerals, vitamins, and amino acids in varying quantities. In this article, we will briefly explore the chemical composition of honey. (Contains 2 figures and…

Ball, David W.



Numerical simulations of crack propagation driven by stress-assisted corrosion in brittle solids and composite materials  

NASA Astrophysics Data System (ADS)

When many glasses and ceramic materials are subject to static loading as well as a chemically reactive environment, they often experience delayed failure due most likely to stress-assisted chemical reactions at the cracks: pre-existing surface flaws grow to a critical length, at which point unstable rapid crack propagation ensues, leading to catastrophic failure. For a given material and ambient environment, the lesser the applied stress, the longer the time to fracture. When the applied stress decreases to a threshold level, known as a fatigue limit or a stress corrosion limit, failure of the solid can be avoided. The mechanisms could be very different under different mechanical and chemical conditions in different solids. We adopt one possible mechanism, which was first proposed by Charles and Hillig in 1961, and develop a numerical approach to predict the fatigue threshold of brittle solid and investigate the nature of crack propagation. Numerical simulations in this dissertation have confirmed many features of stress-assisted corrosion problem and some surprising new insights emerge from calculations. In particular, we find that the behavior of fatigue limit of material is dependent not only on the driving force for material removal, but also on the kinetics of this process. Finally, further calculations have been conducted to investigate the evolution of crack propagation in composite materials. Systematic parametric studies are used to illustrate the influence of material properties and loading on crack path and growth rate along a bi-material interface.

Tang, Zhibo


Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging  

Microsoft Academic Search

Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to\\u000a its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as\\u000a well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by

Notburga Gierlinger; Lanny Sapei; Oskar Paris



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


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

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



Identification of surface composition and chemical states in composites comprised of phases with fluorite and perovskite structures by X-ray photoelectron spectroscopy  

NASA Astrophysics Data System (ADS)

X-ray photoelectron spectroscopy (XPS) has been used to explore the cation rearrangement between the surface and bulk of grains and the surface chemical states of Ce, Mn, Co, Sr, and O ions in the single phase CeO2-based solid solutions and in the two phase (100 - x)La0.6Sr0.4CoO3-xCeO2 (LSCCx) and (100 - x)La0.8Sr0.2MnO3-xCeO2 (LSMCx) composites. The well-resolved Ce 3d5/2 and Ce 3d3/2 spin-orbit components were determined to study the Ce4+ to Ce3+ electronic transition at the surface. The surface of the LSCCx and LSMCx (x = 8-40 mol%) composites is depleted in cerium. Both Ce4+ and Ce3+ cations were revealed. The surface fraction of Ce4+ cations increases with the rise in CeO2 content in both systems, but it is higher by about a factor of two in the LSCC composites. A strong enrichment of the surface by Co cations was observed for the composites LSCCx (x = 8-40 mol%), implying that the presence of cerium could facilitate the Co surface segregation. A slight Sr surface enrichment compared to the nominal stoichiometry was found for La0.6Sr0.4CoO3, CeO2-based solid solutions, LSCC57, and LSMCx (x = 10-57) composites. In contrast, the surface of the LSCCx (x = 10-37) composites is slightly depleted in strontium cations. The O 1s spectra of the LSCC and LSMC composites contain several contributions associated with the lattice oxygen related to the phases with the perovskite and fluorite structures as well as with different surface states. Their contributions vary with CeO2 content and a chemical origin of the transition metal cations on the B-site in the perovskite structure. The Ce2(CO3)3-based phase seems to exist at the surface of grains and crystallites in the LSCC57 and LSCM composites.

Konysheva, Elena Yu; Francis, Stephen M.



Nanostructured composite reinforced material  


A family of materials wherein nanostructures and/or nanotubes are incorporated into a multi-component material arrangement, such as a metallic or ceramic alloy or composite/aggregate, producing a new material or metallic/ceramic alloy. The new material has significantly increased strength, up to several thousands of times normal and perhaps substantially more, as well as significantly decreased weight. The new materials may be manufactured into a component where the nanostructure or nanostructure reinforcement is incorporated into the bulk and/or matrix material, or as a coating where the nanostructure or nanostructure reinforcement is incorporated into the coating or surface of a "normal" substrate material. The nanostructures are incorporated into the material structure either randomly or aligned, within grains, or along or across grain boundaries.

Seals, Roland D. (Oak Ridge, TN); Ripley, Edward B. (Knoxville, TN); Ludtka, Gerard M. (Oak Ridge, TN)



Reversibly assembled cellular composite materials.  


We introduce composite materials made by reversibly assembling a three-dimensional lattice of mass-produced carbon fiber-reinforced polymer composite parts with integrated mechanical interlocking connections. The resulting cellular composite materials can respond as an elastic solid with an extremely large measured modulus for an ultralight material (12.3 megapascals at a density of 7.2 milligrams per cubic centimeter). These materials offer a hierarchical decomposition in modeling, with bulk properties that can be predicted from component measurements and deformation modes that can be determined by the placement of part types. Because site locations are locally constrained, structures can be produced in a relative assembly process that merges desirable features of fiber composites, cellular materials, and additive manufacturing. PMID:23950496

Cheung, Kenneth C; Gershenfeld, Neil



Composite materials and their use in structures  

Microsoft Academic Search

This book attempts to provide a basic fundamental understanding of the physical and mathematical aspects of the materials system and structures comprised of composite materials. The introduction discusses the nature and scope of composite materials, the strengthening processes used in the manufacture of alloys, and the needs for composite materials. Then various types of fiber-reinforced materials are examined, first by

J. R. Vinson; T. W. Chou



Chemical degradation of composite restoratives.  


The chemical environment is one aspect of the oral environment, which could have an appreciable influence on the in vivo degradation of composite restoratives. The effects of chemical media on surface hardness of four composite restoratives (Silux [SX], Z100 [ZO], Ariston [AR] and Surefil [SF]) were investigated. The relationship between hardness and the thickness of the degradation layer was also studied. Thirty six specimens (3 x 4 x 2 mm) were made for each material. Following polymerization, the specimens were stored in artificial saliva at 37 degrees C for 24 h. The specimens were then randomly divided into six groups of six, subjected to microhardness testing (load = 500 gf, dwell time = 15 s) and stored in the following chemicals for 1 week at 37 degrees C: artificial saliva (S), distilled water (W), 0.02 N citric acid (C), 0.02 N lactic acid (L), heptane (H) and 75-25% ethanol-water solution (E). After conditioning, the specimens were again subjected to hardness testing and sectioned. Change in hardness (DH) was computed and the thickness of the degradation layer (DL) was measured using a computerized image analysis system at 600x magnification. Results of statistical analysis (ANOVA/Scheffe's [P < 0.05]) of DH based on materials were as follows: SX - E > all other mediums; ZO - W > C; and AR - S, W, E > H (> indicates significantly greater hardness change). No significant difference in DH was observed between the different chemicals for SF. The effects of chemical media on DH were found to be material dependent. A significant but weak positive correlation (Pearson's correlation [P < 0.05]) exists between change in hardness and thickness of the degradation layer. PMID:11722717

Yap, A U; Tan, S H; Wee, S S; Lee, C W; Lim, E L; Zeng, K Y



Etching of long fiber polymeric composite materials by nanosecond laser induced water breakdown plasma  

NASA Astrophysics Data System (ADS)

Composite materials are widely used in industry due to their superior material properties and light weight. However, shear failure can occur at the interface between the fibers and polymer matrix when a tensile force stretches the matrix more than the fibers. Repairing the damaged composite material appears to be cost effective but still remains a challenge despite extensive research. Laser induced water breakdown plasma, which is generated by the strong interaction between nanosecond laser and water, is proposed in this work to etch the surface layer of a carbon fiber reinforced composite sample. It is found that the polymer layer can be effectively removed by the plasma while the carbon fiber remains almost intact. The dependence of the etching depth on the laser power density, laser focus position, and the number of shots are also investigated in this work. The maximum possible etching depth is around 350 ?m with 50 laser shots at laser power density of 70 GW/cm2.

Cao, Yunfeng; Shin, Yung C.; Pipes, R. Byron



Essential fatty acid contents of various fats: Interpretations of values by physico-chemical tests  

Microsoft Academic Search

Biological assays of oil and fat products, free from isomers of the naturally-occurringcis-9,cis-12 linoleic acid, have been shown to provide estimates of essential fatty acid content which agree well with values obtained\\u000a by spectrophoto-metric analysis. However, when partially hydrogenated fats, such as those used in margarines, are bio-assayed\\u000a the estimates obtained are only about 60% of those derived by spectro-photometric

Roslyn B. Alfin-Slater; Daniel Melnick



Study on influence of vibration behavior of composite material damage by holography  

Microsoft Academic Search

Composite material has been applied widely in aeronautics, astronautics and some other fields due to their high strength, light weight and antifatigue and etc. But in the application, composite material may be destroyed or damaged, which may have impact on its further applications. Therefore, study on the influence of behavior of composite material damage becomes a hot research. In this

Linfeng Guo; Zhimin Zhao; Mingjuan Gao; Xianzhong Zhuang



Energetic composites and method of providing chemical energy  


A method is described 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. 3 figs.

Danen, W.C.; Martin, J.A.



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

NASA Astrophysics Data System (ADS)

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.

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



Orthopedic Composite Materials.  

National Technical Information Service (NTIS)

The program was designed as a pilot project to establish new techniques for making orthopedic prosthetic materials. The basic idea was to make metal supported ceramic composites, so that the metal provided strength (and an element of ductility) and the re...

B. J. Shaw



One-dimensional simulation of hydrogen isotopes diffusion in composite materials by FVM  

Microsoft Academic Search

Tritium diffusion and permeation in construct materials is one of the most important problems in fusion material research. For the tritium concentration evaluation within each sub-system of the fuel cycle of ITER, a finite volume computer program was developed for diffusion analysis of hydrogen isotopes in composite materials. The program calculates hydrogen isotope concentration distributions through composite materials such as

Song Jiangfeng; Huang Zhiyong; Li Lianxia; Chen Chang'an; Luo Deli



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

PubMed Central

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.

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



Bullets fragments identification by comparison of their chemical composition obtained using instrumental neutron activation analysis.  


Bullets found in crime scenes are usually compared by examination of the rifling impressions produced in the barrel of the questioned firearm. When, however, a bullet is fragmented or highly deformed, the comparison of rifling micro striations cannot be performed, and the only way two compare two or more bullets is by a match of their chemical analysis. In spite of the limits of the chemical analysis methods, due to the frequent compositional lead variability of ammunition boxes, the technique still keeps its full value, both as trial element, and as an aid in the investigations. A case is reported in the present paper, in which some crushed and deformed bullets, recovered from a murder victim body, have been analyzed by Instrumental Neutron Activation Analysis. The analysis allowed the assignation of the bullets to one of the ammunitions lots owned by one of the murder suspect. PMID:20591591

Sedda, Antioco Franco; Rossi, Gabriele



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

NASA Astrophysics Data System (ADS)

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.

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



Evaluation of moisture content in porous material by dynamic energy balance  

Microsoft Academic Search

The aim of this paper is to describe a procedure to evaluate the moisture content in porous medium by a non-destructive test. The method is based on the determination of the target thermal inertia by means of the measure of the energy input and the corresponding temperature increase, both obtained by 2-D optical sensors. Since the thermal inertia is strongly

Ermanno G. Grinzato; Chiara Bressan; Paolo G. Bison; Andrea Mazzoldi; Paolo Baggio; Cesare Bonacina



Influence of the polymerization process on composite resistance to chemical degradation by food-simulating liquids.  


This study determined the influence of curing lights and modes on composite resistance to chemical degradation by various food-simulating liquids. Two different types of curing light (Halogen [H]-Elipar Trilight, 3M-ESPE; LED [L]-Freelight, 3M-ESPE) and two curing modes (standard [S]; exponential [E) were evaluated in the study. Forty-five composite (Z100 [3M-ESPE]) specimens were made for each light-curing mode combination (HS, HE, LS and LE). The specimens were randomly divided into five groups of nine and exposed to the following food-simulating liquids (FSL) for one week at 37 degrees C: distilled water, 50% aqueous ethanol solution, heptane and citric acid. Specimens stored in air were used as control. After the one week conditioning period, hardness testing was conducted with a digital microhardness tester (load = 500 gf; dwell time = 15 seconds). Mean hardness (HK)/hardness deterioration (deltaHK) were subsequently computed and data was subjected to analysis using ANOVA/Scheffe's test (p < 0.05). The resistance of composite to chemical degradation by FSL was light/curing mode dependent. Significant differences in HK and deltaHK were observed among the four curing techniques after conditioning in some FSL and air. After conditioning in water and citric acid, specimens polymerized with HE underwent significantly more softening compared to specimens polymerized with HS, LS and LE. PMID:14653286

Yap, Adrian U J; Wattanapayungkul, P; Chung, S M


Chemical compositions of large cluster IDPs  

SciTech Connect

We performed X-ray fluorescence spectroscopy on two large cluster IDPs, which sample the IDP parent body at a mass scale two orders-of-magnitude larger than {approx}10 {micro}m IDPs, allowing proper incorporation of larger mineral grains into the bulk composition of the parent body. We previously determined that {approx}10 {micro}m interplanetary dust particles (IDPs) collected from the Earth's stratosphere are enriched in many moderately volatile elements by a factor of {approx}3 over the CI meteorites. However, these IDP measurements provide no direct constraint on the bulk chemical composition of the parent body (or parent bodies) of the IDPs. Collisions are believed to be the major mechanism for dust production by the asteroids, producing dust by surface erosion, cratering and catastrophic disruption. Hypervelocity impact experiments at {approx}5 km/sec, which is the mean collision velocity in the main belt, performed by Flynn and Durda on ordinary chondrite meteorites and the carbonaceous chondrite meteorite Allende show that the 10 {micro}m debris is dominated by matrix material while the debris larger than {approx}25 {micro}m is dominated by chondrule fragments. Thus, if the IDP parent body is similar in structure to the chondritic meteorites, it is likely that the {approx}10 {micro}m IDPs oversample the fine-grained component of the parent body. We have examined the matrix material from the few meteorites that are sufficiently fine-grained to be samples of potential IDP parent bodies. This search has, thus far, not produced a compositional and mineralogical match to either the hydrous or anhydrous IDPs. This result, coupled with our recent mapping of the element distributions, which indicates the enrichment of moderately volatile elements is not due to contamination on their surfaces, suggests the IDPs represent a new type of extraterrestrial material. Nonetheless, the meteorite fragmentation results suggest that compositional measurements on 10 {micro}m IDPs only provide a direct constraint on the bulk chemical composition of the IDP parent body if the size-scale of the grains in the parent body is <<10 {micro}m. The stratospheric collections include many nonchondritic, mono-mineralic grains, collected along with the fine-grained chondritic IDPs. Some of these grains, which include volatile-poor olivine and pyroxene as well as calcophile-rich sulfides, have fine-grained, chondritic material (i.e., small bits of typical IDPs) adhering to their surfaces. This indicates that at least some of the non-chondritic grains found on the stratospheric collectors are fragments from the same parent as the fine-grained IDPs. Thus, the bulk composition of the IDP parent body can only be reconstructed by adding to the fine-grained, chondritic IDPs the correct amount of this non-chondritic material. Qualitatively, the addition of olivines and pyroxenes will reduce the mean content of many moderately volatile elements while the addition of sulfides will increase the content of some of these elements. However, the quantitative task of adding these monomineralic grains to the fine-grained IDPs cannot be accomplished by simply adding the non-chondritic material in proportion to its occurrence on the stratospheric collectors because: (1) it is not clear that all of the olivines, pyroxenes, sulfides or other mineral grains found on the stratospheric collectors are extraterrestrial; (2) the settling rate of a particle depends on its density and shape, thus the concentration factor for these high-density, mono-mineralic grains is lower at the collection altitude than it is for the lower-density, fine-grained aggregate IDPs; and (3) the atmospheric entry survival of a particle is a function of density, so higher density grains (e.g., sulfides) are more likely to vaporize on entry, even if they enter with the same velocity as fine-grained, lower-density aggregates. The collection of 'cluster IDPs,' which enter the atmosphere as large particles, some larger than 50 {micro}m in diameter, containing both fine-grained aggregate material

Flynn, G.J.; Lanzirotti, A.; Sutton, S.R. (SUNYP); (UC)



Characterization of Al 2O 3–Al nano-composite powder prepared by a wet chemical method  

Microsoft Academic Search

A wet chemical method was used to prepare Al2O3-coated Al nano-size-composite powders using Al, aluminum nitrate and ammonia as the starting materials. TEM, SEM, TG\\/DSC, zeta potential, XPS, X-ray were used to characterize the composite powders. Results showed that a uniform thin Al(OH)3 layer can formed on the surface of Al particles. After calcined at 1000°C for 2h, the thin

Hong-xia Lu; Jie Hu; Chang-ping Chen; Hong-wei Sun; Xing Hu; De-lin Yang



Photochromic organic-inorganic composite materials prepared by sol-gel processing: properties and potentials  

NASA Astrophysics Data System (ADS)

The sol-gel method which features a low-temperature wet-chemical process opens vast possibilities to incorporating organic dyes into solid matrices for various optical applications. In this paper we present our experimental results on the sol-gel derived photochromic organic- inorganic composite (Ormocer) materials following an introductory description of the sol-gel process and a brief review on the state of the art of the photochromic solids prepared using this method. Our photochromic spirooxazine-Ormocer gels and coatings possess better photochromic response and color-change speed than the corresponding photochromic polymer coatings and similar photochemical stability to the latter. Further developments are proposed as to tackle the temperature dependence problem and further tap the potentialities of the photochromic dye-Ormocer material for practical applications.

Hou, Lisong; Mennig, Martin; Schmidt, Helmut



Water-Based Layer-by-Layer Surface Chemical Modification of Biomimetic Materials: Oil Repellency.  


Biomimetic materials possessing hierarchical surface roughness thrive when complementary terminal chemical functionality is introduced. However, incorporating terminal functionality on the biomimetic material is the challenge, especially, when its roughness needs to be preserved. Hence, we report surface chemical modification of biomimetic materials through water-based layer-by-layer deposition. The amine terminated biomimetic replica PDMS-replica(Silica/NH2) was prepared by treating silica-modified replica (i.e., PDMS-replica(Silica)) with the aqueous solution of branched ethoxylated polyethylenimine (EPEI). Next, -CF3 terminal PDMS-replica(Silica/NH2/CF3) was obtained by treating PDMS-replica(Silica/NH2) with the aqueous solution of phosphate ester fluorosurfactant. PDMS-replica(Silica/NH2/CF3) showed superhydrophobicity (advancing ?water ? 140°) and high oil repellency (advancing ?oil ? 110°). X-ray photoelectron spectroscopy (XPS) revealed well-organized terminal -CF3 groups present on the PDMS-replica(Silica/NH2/CF3) surface. During the process of layer-by-layer deposition, the surface topography was monitored using scanning electron microscopy (SEM). This method could be extended to get desired terminal chemical functionality on the biomimetic materials which would furnish interesting surface properties in air or under water. PMID:23942547

Ghosh, Nilmoni; Singh, Amit Vikram; Vaidya, Ashish Anant



Chemical composition and some anti-nutrient content of raw and processed bitter vetch (Vicia ervilia) seed for use as feeding stuff in poultry diet.  


An experiment was conducted to determine chemical composition of raw and treated bitter vetch seed for use in poultry diets. Processing methods were: soaked in water for 12 h, then autoclaved and dried (SA); coarsely ground, soaked in water for 24 h, autoclaved and dried (GSA); coarsely ground, soaked in water for 47 h with exchange of water every 12 h, cooked and dried (GSC); coarsely ground, soaked in solution of 1% acetic acid for 24 h at 60 degrees C and dried (GAA). Raw bitter vetch seed was contained 94.52, 26.56, 0.4, 58.86, 3.38, 5.32, 12.28 and 14.20 percent DM, CP, EE, NFE, Ash, CF, ADF and NDF, respectively. Its GE, AME, AMEn, TME and TMEn values were 18.10, 13.15, 14.38, 14.10 and 14.69 MJ/kg, respectively. Results indicated that bitter vetch is a good source of Fe (340 ppm) and Cu (46.7 ppm). It s amino acid profile was suitable and methionine was the first limiting amino acid when compared with broiler and layer chicks requirements. Its canavanine and tannin content were 0.78 and 6.7 mg/kgDM, respectively. Processing methods improved CP and in some cases AMEn. All processing methods especially GSC resulted in a significant (P < 0.05) reduction in canavanine and tannin. PMID:19052906

Sadeghi, Gh; Pourreza, J; Samei, A; Rahmani, H



Oxygen isotopic compositions of asteroidal materials returned from Itokawa by the Hayabusa mission.  


Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions of rock particles from asteroid 25143 Itokawa returned by the Hayabusa spacecraft. Compositions of the particles are depleted in (16)O relative to terrestrial materials and indicate that Itokawa, an S-type asteroid, is one of the sources of the LL or L group of equilibrated ordinary chondrites. This is a direct oxygen-isotope link between chondrites and their parent asteroid. PMID:21868668

Yurimoto, Hisayoshi; Abe, Ken-ichi; Abe, Masanao; Ebihara, Mitsuru; Fujimura, Akio; Hashiguchi, Minako; Hashizume, Ko; Ireland, Trevor R; Itoh, Shoichi; Katayama, Juri; Kato, Chizu; Kawaguchi, Junichiro; Kawasaki, Noriyuki; Kitajima, Fumio; Kobayashi, Sachio; Meike, Tatsuji; Mukai, Toshifumi; Nagao, Keisuke; Nakamura, Tomoki; Naraoka, Hiroshi; Noguchi, Takaaki; Okazaki, Ryuji; Park, Changkun; Sakamoto, Naoya; Seto, Yusuke; Takei, Masashi; Tsuchiyama, Akira; Uesugi, Masayuki; Wakaki, Shigeyuki; Yada, Toru; Yamamoto, Kosuke; Yoshikawa, Makoto; Zolensky, Michael E



Chemical studies of H chondrites-10 : contents of thermally labile trace elements are unaffected by late heating.  

SciTech Connect

We have used radiochemical neutron activation analysis (RNAA) to determine 15 trace elements, including 10 moderately and highly volatile ones - Rb, Ag, Se, Cs, Te, Zn, Cd, Bi, Tl, In (in increasing volatility order) - in 6 H chondrite falls with low 3He contents. These plus prior RNAA data provide a compositional database of 92 H4-6 chondrite falls. Three suites of samples can be identified from their noble gas contents: 44 with 'normal' contents, and, therefore, 'normal' orbits and cosmic ray exposure histories; 8 that lost radiogenic gases, presumably by shock late in their histories; and 17 that lost cosmogenic gases by heating during close solar approach. We used the standard multivariate statistical techniques of linear discriminant analysis and logistic regression to compare contents of the 10 moderately and highly volatile trace elements, listed above, in these 3 suites. We found no significant differences. This contrasts sharply with similar comparisons involving random falls and H4-6 chondrites that landed on Earth at specific time intervals. Apparently, contents of volatile trace elements in H4-6 chondrites were established early in their histories and they are so retentively sited that loss during later heating episodes did not occur.

Wang, M.-S.; Wolf, S. F.; Lipschutz, M. E.; Chemical Engineering; Purdue Univ.



Production and Application of Chemical Fibers with Special Properties for Manufacturing Composite Materials and Goods of Different Usage.  

National Technical Information Service (NTIS)

The development of modern technologies demands the creation of new nonmetallic, fibrous materials with specific properties. The fibers and materials developed by NII 'Chimvolokno', St. Petersburg, can be divided into two groups. The first group includes h...

R. Levit



A multicontinuum progressive damage model for composite materials motivated by the kinetic theory of fracture  

Microsoft Academic Search

A conventional composite material for structural applications is composed of stiff reinforcing fibers embedded in a relatively soft polymer matrix, e.g. glass fibers in an epoxy matrix. Although composites have numerous advantages over traditional materials, the presence of two vastly different constituent materials has confounded analysts trying to predict failure. The inability to accurately predict the inelastic response of polymer

Shane Christian Schumacher



Preparation of composite materials of polypyrrole and electroactive polymer gel using for actuating system  

Microsoft Academic Search

In the present work we report on preparation of composite materials of polypyrrole and electroactive polymer gel using for the actuating system. Composite materials of conducting polymer and polymer gel prepared by chemical oxidative polymerization. The gels were stimulated by the application of various electric fields. The elasticity of composite materials was significantly increased with ratio of polypyrrole in the

T. Yamauchi; S. Tansuriyavong; K. Doi; K. Oshima; M. Shimomura; N. Tsubokawa; S. Miyauchi; J. F. V. Vincent



Ski Technology And Composite Materials  

NSDL National Science Digital Library

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.



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


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

Gosztola, Beáta; Sárosi, Szilvia; Németh, Eva



Dense, finely, grained composite materials  


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.

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



Dense, finely grained composite materials  


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. 10 figs.

Dunmead, S.D.; Holt, J.B.; Kingman, D.D.; Munir, Z.A.



New coating materials and their preparation by radiation polymerization. III. Antifogging coating composition  

Microsoft Academic Search

Compositions for good antifogging and mar-resistant coatings were investigated. A mixture of hydrolyzed aminoalkylakoxysilane and hydrophilic vinyl monomer was the best combination. Control of suitable viscosity for coating was carried out conveniently by irradiation. The prepolymer was coated and cured by heating to form an antifogging membrane on various base materials such as inorganic glass, CR-39 resin, and poly(methyl methacrylate).

I. Kaetsu; M. Yoshida



Liquid Helium Composite Regenerator Material.  

National Technical Information Service (NTIS)

A cryogenic composite material designed for application to gap regenerators in cyclic cryocoolers operating below 10 K is investigated. The material is a composite of helium self-loaded into a metallic extended surface structure whose dispersion form is s...

T. R. Knowles



Multifunctional Autonomically Healing Composite Material.  

National Technical Information Service (NTIS)

A composite material, contains a polymer, a polymerizer, a corresponding catalyst for the polymerizer, and a plurality of capsules. The polymerizer is in the capsules. The composite material is self-healing.

J. S. Moore N. R. Sottos P. H. Geubelle S. R. Sriram S. R. White



Enhanced Removal of Lead by Chemically and Biologically Treated Carbonaceous Materials  

PubMed Central

Hybrid sorbents and biosorbents were synthesized via chemical and biological treatment of active carbon by simple and direct redox reaction followed by surface loading of baker's yeast. Surface functionality and morphology of chemically and biologically modified sorbents and biosorbents were studied by Fourier Transform Infrared analysis and scanning electron microscope imaging. Hybrid carbonaceous sorbents and biosorbents were characterized by excellent efficiency and superiority toward lead(II) sorption compared to blank active carbon providing a maximum sorption capacity of lead(II) ion as 500??mol?g?1. Sorption processes of lead(II) by these hybrid materials were investigated under the influence of several controlling parameters such as pH, contact time, mass of sorbent and biosorbent, lead(II) concentration, and foreign ions. Lead(II) sorption mechanisms were found to obey the Langmuir and BET isotherm models. The potential applications of chemically and biologically modified-active carbonaceous materials for removal and extraction of lead from real water matrices were also studied via a double-stage microcolumn technique. The results of this study were found to denote to superior recovery values of lead (95.0–99.0 ± 3.0–5.0%) by various carbonaceous-modified-bakers yeast biosorbents.

Mahmoud, Mohamed E.; Osman, Maher M.; Ahmed, Somia B.; Abdel-Fattah, Tarek M.



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

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

M. V. Tesakova; V. I. Parfenyuk



Latent heat nano composite building materials  

Microsoft Academic Search

Heat storage for heating and cooling of buildings reduces the conventional energy consumption with a direct impact on CO2 emissions. The goal of this study was to find the physico-chemical fundamentals for tailoring phase change material (PCM)-epoxy composites as building materials depending on phase change temperature and latent heat using the optimal geometry for each application. Thus, some nano-composite materials

M. Constantinescu; L. Dumitrache; D. Constantinescu; E. M. Anghel; V. T. Popa; A. Stoica; M. Olteanu



Mineral composition and ash content of six major energy crops  

Microsoft Academic Search

The chemical composition of biofuels has not received adequate attention given that it is an important aspect in the introduction of energy crops. In this study, the ash content and mineral composition (C, N, Al, Ca, Cl, Fe, K, Mg, Na, P, S, Si) of stems, leaves and reproductive organs of some promising energy crops were determined and compared with

Andrea Monti; Nicola Di Virgilio; Gianpietro Venturi



Nuclear science and optical studies of InAlGaP materials grown on GaAs by metalorganic chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Quaternary III-V compound InAlGaP, especially In0.5(AlxGa1-x)0.5P which is lattice matched with GaAs, are important materials for visible red-green light emitting diode (LED) and laser diode (LD), solar cell and other optoelectronic and electronic device applications. A set of In0.5(AlxGa1-x)0.5P thin films on GaAs substrates with a wide range of x up to ~80%, were grown by low pressure metalorganic chemical vapor deposition (MOCVD) and studied by a variety of nuclear science and optical analytical techniques, including Rutherford Backscattering Spectrometry (RBS), Raman scattering, photoluminescence (PL), Photoreflectance (PR) and FTIR. Temperature dependent PL-PR measurements over 10-300 K presented the band gap of these InAlGaP materials and variations with composition x and temperature (T). RBS was used to measure the microstructure of AlInGaP films, and through simulation, determine the film thickness and composition precisely. RBS measurement and simulation results indicate a quite fuzzy in the two interfaces, i.e. that there exists diffusion in the majority samples, especially between the AlInGaP layer and substrate. For a certain number of incoming He+ ions,we have proposed a way to determine the error bar by RBS successful. For this series of samples, the error bar of content is around ±1.5%. The error bar of thickness is around ±5.0nm. Different InAlGaP films with different composition and thickness may present different error bars. The results illuminate that RBS is a precise tool to analysis the microstructure of quaternary semiconductor AlInGaP/GaAs samples.

Li, Lin; Hong-Liao, Chi-Jing; Huang, Yi Zhe; Chen, Cheng; Yao, Shude; Qiu, Zi R.; Lin, H. H.; Ferguson, Ian T.; Feng, Zhe Chuan



Chemical compatibility and oxidation resistance of potential matrix and reinforcement materials in ceramic composites for ultra-high temperature applications. Final report, 30 Sep 87-31 Jan 90  

Microsoft Academic Search

The mutual chemical composition and compatibilities of some of the potential matrix and reinforcement phases of ceramic composite materials have been investigated in the temperature range 1600-2200 C. The oxidative stabilities of hot pressed, particulate composites containing 50:50 volume percent of each compound in a material combination have been studied in the temperature range 1000-16000 C. The material combinations investigated




Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging.  


Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by using high resolution (<1 microm) Confocal Raman microscopy. Two-dimensional spectral maps were acquired on cross sections of Equisetum hyemale and Raman images calculated by integrating over the intensity of characteristic spectral regions. This enabled direct visualization of differences in chemical composition and extraction of average spectra from defined regions for detailed analyses, including principal component analysis (PCA) and basis analysis (partial least square fit based on model spectra). Accumulation of silica was imaged in the knobs and in a thin layer below the cuticula. In the spectrum extracted from the knob region as main contributions, a broad band below 500 cm(-1) attributed to amorphous silica, and a band at 976 cm(-1) assigned to silanol groups, were found. From this, we concluded that these protrusions were almost pure amorphous, hydrated silica. No silanol group vibration was detected in the silicified epidermal layer below and association with pectin and hemicelluloses indicated. Pectin and hemicelluloses (glucomannan) were found in high levels in the epidermal layer and in a clearly distinguished outer part of the hypodermal sterome fibers. The inner part of the two-layered cells revealed as almost pure cellulose, oriented parallel along the fiber. PMID:18057960

Gierlinger, Notburga; Sapei, Lanny; Paris, Oskar



Modern Carbon Composite Brake Materials  

Microsoft Academic Search

Carbon-carbon composites used in friction systems are becoming increasingly popular in aircrafts owing to their combination of low weight and high performance. Their current acceptance as brake materials is somewhat restrained due to two factors: cost and performance variations. Many manufacturers are taking steps toward improving their cost efficiency by utilizing lower cost precursor fibers and processing methodologies. At the

Christopher Byrne



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

NASA Astrophysics Data System (ADS)

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.

Zuhlke, Craig A.; Anderson, Troy P.; Alexander, Dennis R.



Method of forming a chemical composition  


A method of forming a chemical composition such as a chemical hydride is described and which includes the steps of selecting a composition having chemical bonds and which is capable of forming a chemical hydride; providing a source of hydrogen; and exposing the selected composition to an amount of ionizing radiation to encourage the changing of the chemical bonds of the selected composition, and chemically reacting the selected composition with the source of hydrogen to facilitate the formation of a chemical hydride.

Bingham, Dennis N. (Idaho Falls, ID); Wilding, Bruce M. (Idaho Falls, ID); Klingler, Kerry M. (Idaho Falls, ID); Zollinger, William T. (Idaho Falls, ID); Wendt, Kraig M. (Idaho Falls, ID)



Composite containing coated fibrous material  

SciTech Connect

This patent describes a process for producing a composite containing at least about 10% by volume of boron nitride coated fibrous material and having a porosity of less than about 20% by volume. It comprises: forming a slurry of infiltration-promoting material and organic binding material in a liquid medium; depositing a coating of boron nitride on fibrous material leaving no significant portion thereof exposed; depositing a silicon-wettable coating on the boron nitride-coated fibrous material leaving no significant portion of the boron nitride exposed; providing the resulting coated fibrous material substantially as a layer; casting the slurry onto the coated fibrous material in an amount sufficient to form a tape therewith; evaporating the liquid medium forming a tape; firing the tape to remove the organic binding material producing a porous body; providing an infiltrant comprised of boron and silicon containing elemental boron in solution in silicon in an amount of at least about 0.1% by weight of elemental silicon; contacting the porous body with infiltrant associated infiltrating means whereby the infiltrant is infiltrated into the porous body; heating the resulting assembly in a partial vacuum to a temperature at which the infiltrant is molten and infiltrating the molten infiltrant into the porous body to produce an infiltrated product; and cooling the product producing the composite.

Singh, R.N.; Gaddipati, A.R.



Effects of chemical compositions and ensiling on the biogas productivity and degradation rates of agricultural and food processing by-products.  


The objective of this study was to investigate the effects of chemical compositions and ensiling on the biogas productivity and degradation rates of agricultural and food processing by-products (AFPBPs) using the biogas potential test. The AFPBPs were classified based on their chemical compositions (i.e., carbohydrate, protein and fat contents). The biogas and methane potentials of AFPBPs were calculated to range from 450 to 777 mL/g volatile solids (VS) and 260-543 mL/g VS, respectively. AFPBPs with high fat and protein contents produced significantly higher amounts of biogas than AFPBPs with high carbohydrate and low fat contents. The degradation rate was faster for AFPBPs with high carbohydrate contents compared to AFPBPs with high protein and fat contents. The lag phase and biogas production duration were lower when using ensiled AFPBPs than when using nonsilage AFPBPs. Among the four different silages tested, two silages significantly improved biogas production compared to the nonsilage AFPBPs. PMID:23770534

Kafle, Gopi Krishna; Kim, Sang Hun



Studies on the chemical composition of kohl stone by X-ray diffractometer.  


Use of Kohl (Surma) creates toxicity or protects eye, is one of the most controversial topic of modern medicines. However, modern researches show that kohl forms a thin film on the eye lens thus avoiding the direct contract of harmful UV radiation and glare of sun with lens. Black and shining particles of galena in kohl shield the eyes from glare and reflection of sun and thus protect them from harmful effect of UV radiation emerging from the sun. Based on these findings and other properties of kohl, it was decided to undertake this study to ascertain it's chemical composition and to correlate these properties scientifically. In the present study, kohl stone obtained from Madina (Saudi Arabia) was analyzed to ascertain it's chemical composition. The chemical analysis and X-ray diffractometer results obtained, showed that the main component of kohl stone is galena (PbS). PMID:20067866

Ullah, Pervaiz Habib; Mahmood, Zafar Alam; Sualeh, Mohammad; Zoha, S M S



Hierarchical zinc oxide materials with multiple porosity prepared by ultrafast temperature gradient chemical gas-phase synthesis.  


The preparation of materials characterized by three types of porosity could be prepared by a continuous chemical gas-phase method. The multistep formation mechanism involves a critical temperature gradient and occurs within seconds. The resulting hollow aerogel materials show superior properties as gas sensors in comparison to materials constructed from compact nanoparticles. PMID:22213088

Dilger, Stefan; Lizandara-Pueyo, Carlos; Krumm, Michael; Polarz, Sebastian



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

NASA Astrophysics Data System (ADS)

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.

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



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

SciTech Connect

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.

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



Microstructure and Tribological Properties of CrTiAlN Composite Coatings With Different Chemical Compositions Deposited by Multi-Arc-Ion Plating Technology  

Microsoft Academic Search

The CrTiAlN composite coatings with different chemical composition are deposited on the surface of 65 Mn steels by multi-ion plating technology in a gas mixture of Ar + N2. The metallic ratio of Cr, Ti, and Al was varied by adjusting the currents of different TiAl targets. The coatings were character- ized by means of energy dispersive X-ray analysis, X-ray

Cai Zhihai; Di Yuelan; Zhang Ping



Joining of polymer composite materials  

SciTech Connect

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.

Magness, F.H.



Method to fabricate layered material compositions  

SciTech Connect

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 spectral range.

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



Comparative study of the antioxidant capacity and polyphenol content of Douro wines by chemical and electrochemical methods.  


A comparative study of the antioxidant capacity and polyphenols content of Douro wines by chemical (ABTS and Folin-Ciocalteau) and electrochemical methods (cyclic voltammetry and differential pulse voltammetry) was performed. A non-linear correlation between cyclic voltammetric results and ABTS or Folin-Ciocalteau data was obtained if all types of wines (white, muscatel, ruby, tawny and red wines) are grouped together in the same correlation plot. In contrast, a very good linear correlation was observed between the electrochemical antioxidant capacity determined by differential pulse voltammetry and the radical scavenging activity of ABTS. It was also found that the antioxidant capacity of wines evaluated by the electrochemical methods (expressed as gallic acid equivalents) depend on background electrolyte of the gallic acid standards, type of electrochemical signal (current or charge) and electrochemical technique. PMID:23768395

Rebelo, M J; Rego, R; Ferreira, M; Oliveira, M C



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

NASA Astrophysics Data System (ADS)

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.

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



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

NASA Astrophysics Data System (ADS)

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.

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



Fracture Mode Research of Boron Aluminum Composite Materials by Acoustic Emission (AE),  

National Technical Information Service (NTIS)

Acoustic Emission (AE) characteristics were investigated for various failure modes (such as fiber breakage, matrix crazing, and delamination) of boron reinforced aluminum composite materials. Tensile tests were conducted on four types of specimens (unidir...

Y. Sofue A. Ogawa



Energy Absorption of Composite Materials.  

National Technical Information Service (NTIS)

This paper results of a study on the energy absorption characteristics of selected composite material systems and compares the results with aluminum. Composite compression tube specimens were fabricated with both tape and woven fabric prepreg using graphi...

G. L. Farley



Inspection of objects made of composite materials by the method of computerized X-ray tomography  

Microsoft Academic Search

The application of computerized X-ray tomography (CXT) to inspection of the structural characteristics of composite materials is briefly discussed. A formula is derived for selecting the optimum X-ray energy for various types of composite structure, including powdered metal rods; porous rubber with a powdered filler; a three layered block of synthetic foam plastic; and briquettes of pressed organic chips and




Analysis of internal structures of composite materials by second-order property of mosaic patterns  

Microsoft Academic Search

Properties of composite materials depend on their internal structures which in most cases are highly random. Therefore, high-order information is often required for quantitative characterization of morphological features in spatial distributions of the constituent phases. The present study develops a general expression for a second-order moment, that is, autocorrelation function Rx?, of multiphase heterogeneous composites. The obtained Rx? depends on

Yunping Xi



Drilling Risers for Great Water Depths: Advantage for Mass Reduction by Means of Composite Materials.  

National Technical Information Service (NTIS)

Composite material lines processed from carbon and glass fiber composites were manufactured in pieces of 15 m length and then fitted to an operational drilling riser, in parallel with the working lines. A reduction of dynamic stress was expected. The line...

P. Odru J. C. Guichard



Multi-scaled polymer-based composite materials synthesized by mechanical alloying  

Microsoft Academic Search

Multi-scaled composite materials are of great importance, because they exhibit higher mechanical properties than those attained using conventional fillers or polymer blends. In this work, multi-scaled composite materials based on ultra-high-molecular weight polyethylene (UHMWPE), quasicrystals, polyimide and bronze are investigated for use in the moving parts of machines, gears, bearings, and sliding elements. The main object is to investigate the

S. D. Kaloshkin; L.-J. Vandi; V. V. Tcherdyntsev; E. V. Shelekhov; V. D. Danilov



Barium content of benthic foraminifera controlled by bottom-water composition  

Microsoft Academic Search

THE carbon isotope ratio (delta13C) and cadmium content (Cd\\/Ca) of benthic foraminifera shells have been used to reconstruct deep-water circulation patterns of the glacial oceans1-7. These tracers co-vary with phosphorus in the modern ocean because they are nearly quantitatively regenerated from sinking biological debris in the upper water column. Hence they can be used to reconstruct the distribution of labile

D. Lea; E. Boyle



Chemical composition of selected edible nut seeds.  


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

Venkatachalam, Mahesh; Sathe, Shridhar K



Titan's Interior Chemical Composition: A Thermochemical Assessment*  

NASA Astrophysics Data System (ADS)

We study the interior composition of Titan using thermal chemical equilibrium calculations that are valid to high pressures and temperatures. The equations of state are based on exponential-6 fluid theory and have been validated against experimental data up to a few Mbars in pressure and approximately 20000K in temperature. In addition to CHNO molecules, we account for multi-phases of carbon, water and a variety of metals such as Al and Fe, and their oxides. With these fluid equations of state, chemical equilibrium is calculated for a set of product species. As the temperature and pressure evolves for increasing depth in the interior, the chemical equilibrium shifts. We assume that Titan is initially composed of comet material, which we assume to be solar, except for hydrogen, which we take to be depleted by a factor 1/690. We find that a significant amount of nitrogen is in the form of n2, rather than nh3. Moreover, above 12 kbars, as is the interior pressure of Titan, a significant amount of the carbon is in the form of graphite, rather than co2 and ch4. We discuss the implications of these results for understanding the atmospheric and surface composition of Titan. • This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.

Howard, Michael; Zaug, J. M.; Khare, B. N.; McKay, C. P.



Chemical composition, microstructure and magnetic characteristics of yttrium iron garnet (YIG, Ce:YIG) thin films grown by rf magnetron sputter techniques  

Microsoft Academic Search

YIG thin films were grown by rf magnetron sputter techniques. We investigated the effect of post-deposition heat-treatment as well as various deposition parameters such as substrate materials, substrate temperature, sputter power, and sputter gas types on the crystallinity, chemical composition, microstructure and magnetic characteristics of the films. Post-deposition heat-treatment over 750°C was applied to crystallize as-prepared amorphous films, and a

Myung-Beom Park; Byung Jin Kim; Nam-Hee Cho



Composition control of Hf1-xSixO2 films deposited on Si by chemical-vapor deposition using amide precursors  

NASA Astrophysics Data System (ADS)

Hafnium silicate (Hf1-xSixO2) films were deposited by metalorganic chemical-vapor deposition with composition x ranging from 0 to 1 using amide precursors in an organic solvent. The liquid precursors, tetrakis(diethylamido)hafnium, Hf[N(C2H5)2]4, and tetrakis(dimethylamido)silicon, Si[N(CH3)2]4, are compatible when mixed in solution, have high elemental purity, and exhibit a low halogen content. Thin oxide films were deposited with these precursors over a range of wafer temperatures from 400 to 600 °C with very low carbon and nitrogen incorporation. Control of the film composition is attained by changing the ratio of silicon concentration to hafnium concentration in the precursor solution for specific deposition conditions. Composition and growth rate are reported as a function of process condition. Interfacial layers of less than 10 Å were observed by high-resolution transmission electron microscopy.

Hendrix, B. C.; Borovik, A. S.; Xu, C.; Roeder, J. F.; Baum, T. H.; Bevan, M. J.; Visokay, M. R.; Chambers, J. J.; Rotondaro, A. L. P.; Bu, H.; Colombo, L.




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...


Abruptness of Ge composition at the Si\\/SiGe interface grown by ultrahigh vacuum chemical vapor deposition  

Microsoft Academic Search

A model is proposed to estimate the interfacial abruptness of the Si\\/SiGe heterojunction. In this model, a transition region with linearly graded Ge composition is assumed at the Si\\/SiGe interface. The Ge composition x of Si\\/SiGe quantum well grown by ultrahigh vacuum chemical vapor deposition at 550 °C is found to increase with the deposition time as deposition at the

W. C. Tsai; C. Y. Chang; T. G. Jung; T. S. Liou; G. W. Huang; T. C. Chang; L. P. Chen; H. C. Lin



Improvement of mechanical properties of graphene oxide\\/poly(allylamine) composites by chemical crosslinking  

Microsoft Academic Search

Graphite oxide was prepared by oxidation of graphite using the Hummers method, and its ultrasonication in water yielded dispersed graphene oxide (GO) sheets. These sheets were then crosslinked with a water soluble polymer, namely poly (allylamine) hydrochloride (PAH), by carbodiimide coupling. Free standing composite films were obtained by filtration. These crosslinked composites showed better mechanical properties than unmodified GO films

Amro Satti; Patrick Larpent; Yurii Gun’ko



Chemical vapor infiltration of non-oxide ceramic matrix composites  

SciTech Connect

Continuous fiber ceramic composites are enabling new, high temperature structural applications. Chemical vapor infiltration methods for producing these composites are being investigated, with the complexity of filament weaves and deposition chemistry merged with standard heat and mass transport relationships. Silicon carbide- based materials are, by far, the most mature, and are already being used in aerospace applications. This paper addresses the state-of-the-art of the technology and outlines current issues.

Besmann, T.M.; Stinton, D.P.; Lowden, R.A.



Global Chemical Compositions Of Spiral Galaxies  

NASA Astrophysics Data System (ADS)

Understanding the chemical composition of a galaxy is vital to tracing its global evolution. However, characterizing overall abundances for spirals poses a challenge since these galaxies tend to possess gradients in their chemical compositions. Here, a recent proposal for determining global oxygen abundances for spirals is explored and extended. By separately integrating the absolute amounts of hydrogen and oxygen within circles of increasing radii, it is shown that the overall oxygen abundance generally approaches an asymptote. The asymptote is a viable measure of the overall chemical state of a spiral, and allows for comparisons of the chemical evolution with respect to other galaxies, such as dwarf irregulars, whose chemistry is better understood.

Dack, Stuart; McCall, M.



Analysis of neutron diffraction peak broadening caused by internal stresses in composite materials  

SciTech Connect

Neutron diffraction is an essential tool in the study of internal stresses in composite materials. In most work only the peak shifts caused by the related elastic strains are considered, but other valuable information exists in the form of peak shape changes. The conditions under which the pure diffraction profile of the composite (i.e. the profile when all sources of broadening not caused by the residual stresses are removed) represents the probability distribution of the peak shifts corresponding to the strains are examined. It is shown that in these conditions, the pure diffraction profile has no attributes of particle size broadening (and vice versa), thereby providing a test for the validity of results interpreted in this way. The experimental derivation of measured strain distributions in Al{sub 2}O{sub 3}/SiCp composites using neutron diffraction is described. No apparent particle size broadening was detected, demonstrating the validity of the results, which also satisfied other tests for consistency.

Todd, R.I.; Borsa, C.; Derby, B. [Univ. of Oxford (United Kingdom). Dept. of Materials; Bourke, M.A.M. [Los Alamos National Lab., NM (United States)



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

NASA Astrophysics Data System (ADS)

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.

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



Properties and Chemical Composition of Typical Coker Gas Oil  

Microsoft Academic Search

The coker gas oil from Daqing, Shengli, and Liaohe, which are three famous oil fields in China, are studied. The properties, chemical composition, and structural composition of coker gas oil from Daqing, Shengli, and Liaohe saturated hydrocarbon are analyzed. The results show that nitrogen and sulfur content in Daqing coker gas oil is the lowest, and saturated hydrocarbon content is

B. Hou; Z. Cao; W. Chen; J. Han



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  

NASA Astrophysics Data System (ADS)

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 large tectonically emplaced mantle slices (orogenic massifs) led to a completely different view, with S contents clustering around 200 +/- 50 ppm in undepleted to slightly depleted Iherzolites. This later value fits rather well the model S content for mid ocean ridge basalt (MORB) source mantle as well as primitive mantle estimates. Ivnov et al. conclude that basalt-borne xenoliths and massive peridotites may have sampled different mantle reservoirs in regard to S, the former being representative of the rigid continental mantle and the later of the convecting MORB source asthenosphere. Meanwhile, however, they cast some doubt on the representativity of the massive peidotites as regards mantle sulfur. Sulfur is of prime concern in mantle geochemistry because sulfides concentrate 60-80% of the total Pd and Au content present in the upper mantle. The existence of two mantle reservoirs with contrasting ranges of sulfur concentrations should result in significant differences in the contents of these elements. The author attempts to re-emphasize some results from previous publications that have been misquoted by Ionov et al. and reassesses some of the literature data relevant to mantle xenoliths and used by Ionov et al. to support their view of the sulfur content of the subcontinental upper mantle. Finally the author envisages the implication of two contrasting mantle sulfur reservoirs for the distriburtion of siderophile elements.

Lorand, J. P.



Micromanufacturing Of Hard To Machine Materials By Physical And Chemical Ablation Processes  

SciTech Connect

Miniaturization leads to high requirements to the applied manufacturing processes especially in respect to the used hard to machine materials and the aims of structure size and geometrical accuracy. Traditional manufacturing processes reach their limits here. One alternative for these provide thermal and chemical ablation processes. These processes are applied for the production of different microstructures in different materials like hardened steel, carbides and ceramics especially for medical engineering and tribological applications.

Schubert, A. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz, 09126 (Germany); Chair Micromanufacturing Technology, Chemnitz University of Technology, Chemnitz, 09107 (Germany); Edelmann, J.; Gross, S.; Meichsner, G.; Wolf, N.; Schneider, J. [Fraunhofer Institute for Machine Tools and Forming Technology IWU, Chemnitz, 09126 (Germany); Zeidler, H.; Hackert, M. [Chair Micromanufacturing Technology, Chemnitz University of Technology, Chemnitz, 09107 (Germany)



Optical sensor using functionalized composite materials  

US Patent & Trademark Office Database

The invention relates to a method for sensing the presence of at least one analyte in a medium, comprising disposing in the medium a functionalized composite material such that the at least one analyte is absorbed by the functionalized composite material, the functionalized composite material having at least one optical property that is modulated by absorption of the at least one analyte; and measuring modulation of the at least one optical property of the functionalized composite material; wherein modulation of the at least one optical property of the functionalized composite material is indicative of the presence of the analyte in the medium. The invention also relates to an optical sensor for sensing the presence of at least one analyte in a medium, and a functionalized composite material having at least one optical property that is modulated upon absorption of one or more analyte.



The physicochemical properties and chemical composition of trehalose lipids produced by Rhodococcus erythropolis 51T7.  


This study analyzed the chemical and physical properties of a biosurfactant synthesized by Rhodococcus sp. 51T7. The biosurfactant was a trehalose tetraester (THL) consisting of six components: one major and five minor. The hydrophobic moieties ranged in size from 9 to 11 carbons. The critical micelle concentration (CMC) was 0.037g L(-1) and the interfacial tension against hexadecane was 5mN m(-1). At pH 7.4 the glycolipid CMC/critical aggregation concentration (CAC) was 0.05g L(-1) and at pH 4 it was 0.034g L(-1). A phase diagram revealed effective emulsification with water and paraffin or isopropyl myristate. A composition of 11.3-7.5-81.8 (isopropyl myristate-THL-W) was stable for at least 3 months. The HLB was 11 and the phase behaviour of the glycolipid revealed the formation of lamellar and hexagonal liquid-crystalline textures. PMID:19428355

Marqués, A M; Pinazo, A; Farfan, M; Aranda, F J; Teruel, J A; Ortiz, A; Manresa, A; Espuny, M J



Advertising Content in Physical Activity Print Materials.  

ERIC Educational Resources Information Center

|Evaluated the advertising content contained in physical activity print materials. Analysis of print materials obtained from 80 sources (e.g., physicians' offices and fitness events) indicated that most materials contained some form of advertising. Materials coming from commercial product vendors generally contained more advertising than materials

Cardinal, Bradley J.



Composite material heat pipe radiator  

Microsoft Academic Search

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

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



Determination of chemical composition of insoluble residue of spent fuel by total reflection X-ray fluorescence spectrometry.  

National Technical Information Service (NTIS)

The analysis method of chemical composition of insoluble residue of spent PWR fuel has been developed by using a self-made prototype of total reflection X-ray fluorescence spectrometer. The simulated sample of insoluble residue of spent PWR fuel was analy...

Jin Liyun Huang Qingliang Yuan Hui Li Yun Zhu Liang



Oxygen Isotopic Compositions of Asteroidal Materials Returned from Itokawa by the Hayabusa Mission  

Microsoft Academic Search

Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but oxygen isotopic compositions of asteroids themselves have not been established. We measured, using secondary ion mass spectrometry, oxygen isotopic compositions of rock particles from asteroid 25143 Itokawa returned by the Hayabusa

Hisayoshi Yurimoto; Ken-ichi Abe; Masanao Abe; Mitsuru Ebihara; Akio Fujimura; Minako Hashiguchi; Ko Hashizume; Trevor R. Ireland; Shoichi Itoh; Juri Katayama; Chizu Kato; Junichiro Kawaguchi; Noriyuki Kawasaki; Fumio Kitajima; Sachio Kobayashi; Tatsuji Meike; Toshifumi Mukai; Keisuke Nagao; Tomoki Nakamura; Hiroshi Naraoka; Takaaki Noguchi; Ryuji Okazaki; Naoya Sakamoto; Yusuke Seto; Masashi Takei; Akira Tsuchiyama; Masayuki Uesugi; Shigeyuki Wakaki; Toru Yada; Kosuke Yamamoto; Makoto Yoshikawa; Michael E. Zolensky



Joining of composite materials  

SciTech Connect

This Conference Proceedings contains 9 papers, of which one is abstracted separately, describing the latest achievement in effective methods of joining of composite structures. Most composite systems do not deform plastically and thus cannot alleviate stress concentration. The papers cover the design, analysis, testing and inspection of joined interfaces. Data are given for both mechanically fastened and adhesively bonded joints.

Kedward, K.T.



Variations in T2* and Fat Content of Murine Brown and White Adipose Tissues by Chemical-Shift MRI  

PubMed Central

Purpose To compare T2* relaxation times and proton density fat-fraction (PDFF) values between brown (BAT) and white (WAT) adipose tissue in lean and ob/ob mice. Materials and Methods A group of lean male mice (n=6), and two groups of ob/ob male mice placed on similar four-week (n=6) and eight-week (n=8) ad libitum diets, were utilized. The animals were imaged at 3 Tesla using a T2*-corrected chemical-shift based water-fat MRI method that provides simultaneous estimation of T2* and PDFF on a voxel-wise basis. Regions of interest were drawn within the interscapular BAT and gonadal WAT depots on co-registered T2* and PDFF maps. Measurements were assessed using analysis of variance, Bonferroni-adjusted t-test for multi-group comparisons, and the Tukey post-hoc test. Results Significant differences (p<0.01) in BAT T2* and PDFF were observed between the lean and ob/ob groups. The ob/ob animals exhibited longer BAT T2* and greater PDFF than lean animals. However, only BAT PDFF was significantly different (p<0.01) between the two ob/ob groups. When comparing BAT to WAT within each group, T2* and PDFF values were consistently lower in BAT than WAT (p<0.01). The difference was most prominent in the lean animals. In both ob/ob groups, BAT exhibited very WAT-like appearances and properties on the MRI images. Conclusion T2* and PDFF are lower in BAT than WAT. This is likely due to variations in tissue composition. The values were consistently lower in lean mice than in ob/ob mice, suggestive of the former’s greater demand for BAT thermogenesis and reflective of leptin hormone deficiencies and diminished BAT metabolic activity in the latter.

Hu, Houchun H.; Hines, Catherine D.G.; Smith, Daniel L.; Reeder, Scott B.



Controlling charge transport in blue organic light-emitting devices by chemical functionalization of host materials  

SciTech Connect

Generation of white light from OLEDs for general lighting applications requires a highly efficient blue component. However, a stable and power efficient blue OLED component with simple device architecture remains a significant challenge partly due to lack of appropriate host materials. Here we report the photophysical and device properties of ambipolar host phosphine oxide based materials. In this work, we studied the effect of the structural modification made to phosphine oxide-based hosts on the charge balance. We observed significant changes in charge transport within the host occurred upon small modifications to their chemical structure. As a result, an alteration of the chemical design of these materials allows for the control of charge balance of the OLED.

Polikarpov, Evgueni; Koech, Phillip K.; Wang, Liang; Swensen, James S.; Cosimbescu, Lelia; Rainbolt, James E.; Von Ruden, Amber L.; Gaspar, Daniel J.; Padmaperuma, Asanga B.



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


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

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



Review of Recent Developments. Advanced Composite Materials.  

National Technical Information Service (NTIS)

Contents: Hybrid composites, Beryllium-wire reinforced alloys by roll bonding, Transverse strength of ductile-fiber-reinforced metals, Transverse strength of brittle-fiber-reinforced alloys, Transverse strength of Al2O3-filament reinforced nickel-chromium...

K. R. Hanby



Chemical Compatibility of Polymeric Materials.  

ERIC Educational Resources Information Center

|Presents some principles for specifying general classes of polymers for predicting relative chemical attack from acids, bases, oxidants, and certain common antagonists. Also discusses predicting relative solvent effects. Suggests uses of this information in two or three lectures in a chemical engineering materials course. (YP)|

Solen, Kenneth A.; Kuchar, Marvin C.



Leaf Xanthophyll content and composition in sun and shade determined by HPLC  

Microsoft Academic Search

As a part of our investigations to test the hypothesis that zeaxanthin formed by reversible de-epoxidation of violaxanthin serves to dissipate any excessive and potentially harmful excitation energy we determined the influence of light climate on the size of the xanthophyll cycle pool (violaxanthin + antheraxanthin + zeaxanthin) in leaves of a number of species of higher plants. The maximum

Susan S. Thayer; Olle Björkman



Nanocellulose reinforced chitosan composite films as affected by nanofiller loading and plasticizer content  

Technology Transfer Automated Retrieval System (TEKTRAN)

Chitosan is a biopolymer obtained by N-deacetylation of chitin, produced from shellfish waste, which may be employed to elaborate edible films or coatings to enhance shelf life of food products. This study was conducted to evaluate the effect of different concentrations of nanofiller (cellulose nan...


27 CFR 19.308 - Spirits content of chemicals produced.  

Code of Federal Regulations, 2013 CFR

...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...



Structure and properties of hybrid composite materials  

NASA Astrophysics Data System (ADS)

The structure and interfacial interaction are studied in the hybrid aluminum-matrix composite materials fabricated by reactive casting combined with mechanical mixing of fillers with a metallic melt. The following types of hardening are considered: hardening by ceramic particles and by the phases formed as isolated inclusions or coatings on ceramic particles during in situ reactions. The hardness and tribological properties of the composite materials as functions of their compositions are discussed.

Chernyshova, T. A.; Kobeleva, L. I.; Bolotova, L. K.; Katin, I. V.



Synthesis of nanostructured carbon materials by open-air laser-induced chemical vapor deposition  

Microsoft Academic Search

Elemental carbon in the sp2 hybridization state can form a great variety of graphitic and amorphous structures. Carbon nanotube is a well-known form of graphitic carbon that has remarkable mechanical, electronic and electrochemical properties with applications ranging from reinforced composite materials to micro-scale electronic devices. Pyrolytic carbon film with turbostratic structure is a form of amorphous carbon that possesses excellent

Kinghong Kwok



Chemical machining of Zerodur material with atmospheric pressure plasma jet  

Microsoft Academic Search

The material of Zerodur is widely used in high performance optics because of its excellent thermal stability characteristics. This paper deals with the development of an APPJ (Atmospheric Pressure Plasma Jet) chemical machining process for defect free and high efficiency machining of Zerodur. The APPJ chemical machining mechanism for multi-phase multi-composite materials is presented. The chemical property of the plasma

Y. X. Yao; B. Wang; J. H. Wang; H. L. Jin; Y. F. Zhang; S. Dong



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

SciTech Connect

Four Permian to Carboniferous torbanites of various geographical origins were examined by transmission micro-FTIR spectroscopy on doubly polished thin sections (10--25 [mu]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[double bond]O, and aromatic C[double bond]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-catalyzed 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. 69 refs., 9 figs., 4 tabs.

Landais, P.; Rochdi, A. (GDR CNRS-CREGU, Vandoeuvre (France)); Largeau, C.; Derenne, S. (UA CNRS 1381, Paris (France))



Effect of material configuration on strengthening of concrete slabs by CFRP composites  

Microsoft Academic Search

While there have been a large number of studies related to strengthening of concrete beams, girders and slabs through the use of externally bonded fiber reinforced polymer (FRP) composites, there has been very little emphasis on investigating the effect of material configuration (primarily related to the process used to fabricate the strips). This paper reports on the strength, failure mechanisms

Hedong Niu; Alvaro Vasquez; Vistasp M. Karbhari



Lead uptake by algae Gelidium and composite material particles in a packed bed column  

Microsoft Academic Search

Biosorption of lead ions was studied in a flow-through column packed with red algae Gelidium and a composite material (industrial algal waste from the agar extraction process immobilized with polyacrylonitrile). Experiments were performed in order to study the effect of important design parameters such as flow rate and influent pH. The breakthrough curves for lead and proton concentrations were obtained

Vítor J. P. Vilar; Cidália M. S. Botelho; Rui A. R. Boaventura



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

NASA Astrophysics Data System (ADS)

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.

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



The compensatory response of pigs previously fed a diet with an increased fibre content. 2. Chemical body components and composition of daily gain  

Microsoft Academic Search

The composition of the daily gain of pigs previously fed a high-fibre diet (HF) was investigated in 60 pigs growing from 25 to 105 kg body weight (BW) using a comparative slaughter technique. From 25 kg body weight (BW), the pigs were fed the HF diet up to 50 (group HF50) or 80 (group HF80) kg BW, followed by feeding

G. Skiba; D. Weremko; H. Fandrejewski


Thermal expansion and mechanical properties of high reinforcement content SiC p\\/Cu composites fabricated by squeeze casting technology  

Microsoft Academic Search

High reinforcement content SiCp\\/Cu composites (?p=50%, 55% and 60%) for electronic packaging applications were fabricated by patent cost-effective squeeze-casting technology. The composites appear to be free of pores, and the SiC particles are distribute uniformly in the composites. The mean linear coefficients of thermal expansion (CTEs, 20–100 °C) of as-cast SiCp\\/Cu composites range from 8.8×10?6 °C?1 to 9.9×10?6 °C?1 and

Guo-qin CHEN; Zi-yang XIU; Song-he MENG; Gao-hui WU; De-zhi ZHU



Nondestructive evaluation of advanced ceramic composite materials  

SciTech Connect

Nondestructive evaluation techniques were developed to characterize performance degrading conditions in continuous fiber-reinforced silicon carbide/silicon carbide composites. Porosity, fiber-matrix interface bond strength, and physical damage were among the conditions studied. The material studied is formed by chemical vapor infiltration (CVI) of the matrix material into a preform of woven reinforcing fibers. Acoustic, ultrasonic, and vibration response techniques were studied. Porosity was investigated because of its inherent presence in the CVI process and of the resultant degradation of material strength. Correlations between porosity and ultrasonic attenuation and velocity were clearly demonstrated. The ability of ultrasonic transmission scanning techniques to map variations in porosity in a single sample was also demonstrated. The fiber-matrix interface bond was studied because of its importance in determining the fracture toughness of the material. Correlations between interface bonding and acoustic and ultrasonic properties were observed. These results are presented along with those obtained form acoustic and vibration response measurements on material samples subjected to mechanical impact damage. This is the final report on research sponsored by the US Department of Energy, Fossil Energy Advanced Research and Technology Development Materials Program. 10 refs., 24 figs., 2 tabs.

Lott, L.A.; Kunerth, D.C.; Walter, J.B.



Mechanics of composite materials  

Microsoft Academic Search

The book presents a comprehensive account of the basic theory of the mechanical behavior of heterogeneous materials. Basic results of continuum mechanics concerning elasticity theory, viscoelasticity theory, plasticity theory and Eshelby's formula are summarized, and the stiffness or effective moduli of materials containing spherical inclusions and cylindrical and lamellar systems are examined in detail. Laminates are discussed, and the analysis,

R. M. Christensen



Fast Formation of Conductive Material by Simultaneous Chemical Process for Infilling Through-Silicon Via  

NASA Astrophysics Data System (ADS)

It is necessary to develop a fast and inexpensive fabrication process of vertical electric wiring by through-silicon via (TSV) technology for advanced three-dimensional semiconductor devices. In this research, a fast-forming conductive composite was successfully developed by simultaneous deposition of conductive organic polymer (polypyrrole) and metal (silver) from the liquid phase, accelerated by photoirradiation. The growth rate of the composite was 38 nm\\cdots-1, which is more than 10 times higher than that of copper by conventional plating. The electric conductivity of the composite was 2.1× 104 ?-1\\cdotcm-1, which is on the same level as general metal conductors. In addition, the effects of reaction conditions on the growth rate and the conductivity of the composites were revealed. From these results, the infilling time of the TSV was expected to shorten from the present 2--10 h to 5--10 m.

Kawakita, Jin; Chikyow, Toyohiro



Al-matrix composite materials reinforced by Al-Cu-Fe particles  

NASA Astrophysics Data System (ADS)

Al-matrix material composites were produced using hot isostatic pressing technique, starting with pure Al and icosahedral (i) Al-Cu-Fe powders. Depending on the processing temperature, the final reinforcement particles are either still of the initial i-phase or transformed into the tetragonal ?-Al00.70Cu0.20Fe0.10 crystalline phase. Compression tests performed in the temperature range 293K - 823K on the two types of composite, i.e. Al/i and Al/?, indicate that the flow stress of both composites is strongly temperature dependent and exhibit distinct regimes with increasing temperature. Differences exist between the two composites, in particul ar in yield stress values. In the low temperatureregime (T <= 570K), the yield stress of the Al/? composite is nearly 75% higher than that of the Al/i composite, while for T > 570K both composites exhibit similar yield stress values. The results are interpreted in terms of load transfer contribution between the matrix and the reinforcement particles and elementary dislocation mechanisms in the Al matrix.

Bonneville, J.; Laplanche, G.; Joulain, A.; Gauthier-Brunet, V.; Dubois, S.



Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder.  


Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively. The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril powder samples were 60 and 12 mg/100 g where as in pink aril powder 62 and 16 mg/100 g, respectively. The anthocyanin content in pink powder decreased from 50.5 to 11.2 and 14.1 mg/100 g in samples packed in polyethylene (PE) and metalised polyester polyethylene laminated pouches respectively. Total polyphenol amount increased in both the powders irrespective of packaging material. Sorption isotherms indicated that both white and pink aril powders were hygroscopic and equilibrated at low relative humidity of 28 and 32%, respectively. PMID:23572721

Rao, Galla Narsing; Nagender, Allani; Satyanarayana, Akula; Rao, Dubasi Govardhana



Electromagnetic shielding effectiveness of composite material  

Microsoft Academic Search

The purpose of this paper is to present an engineering study of the electromagnetic shielding effectiveness of composite materials used in space applications. The objective of the study is to identify and quantify the important electrical characteristics of composite materials proposed as substitutes for conventional metal-based structural elements of spacecraft. Current design practices utilized by various developers of spacecraft, particularly

Patrick J. Serna; Gary H. Liechty



Exposure Assessment of Chemicals from Packaging Materials  

Microsoft Academic Search

A variety of chemicals may enter our food supply, by means of intentional or unintentional addition, at different stages of\\u000a the food chain. These chemicals include food additives, pesticide residues, environmental contaminants, mycotox-ins, flavoring\\u000a substances, and micronutrients. Packaging systems and other food-contact materials are also a source of chemicals contaminating\\u000a food products and beverages. Monitoring exposure to these chemicals has

Maria de Fátima Poças; Timothy Hogg



Fracture mechanics of composite materials  

Microsoft Academic Search

The above circumstances lead to models based on a discussion of the structure of a composite being used most frequently in the fracture mechanics of composite materials. In view of the stochastic properties of the elements in the structure, especially the dispersion in the strength of the fibers, stochastic fracture models are widely used [4-7]. Nevertheless, there has been no

V. V. Bolotin



Comparative chemical composition of the essential oils obtained by microwave-assisted hydrodistillation and hydrodistillation from Agrimonia pilosa LEDEB. Collected in three different regions of China.  


Conventional hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) were performed to obtain the volatile oils of Agrimonia pilosa Ledeb. harvested in three different regions of China, which were subsequently characterized by GC-FID and GC/MS analyses. Compared with HD, MAHD was advantageous in terms of energy savings and extraction time (60 vs. 240?min for MAHD and HD, resp.). The chemical composition varied among the different oils obtained, and the variations in the contents of the main constituents of the oils were irregular. Hence, these variations affected both the quantity and composition of the oils. The oil yields (0.15-0.21%) were affected by the method of extraction and the region of harvest, with the maximum amount of oil obtained by MAHD for the plants collected in Hubei (HB) and the minimum yield obtained by HD for the plants from Zhejing (ZJ). Hexadecanoic acid constituted the major compound of the essential oils, with the highest content found in the oil obtained by HD for plants from HB (41.18%) and the lowest one found in the oil obtained by MAHD from plants from ZJ (11.83%). Microwave irradiation did not adversely affect the composition of the essential oils. The findings show that MAHD is a modern, green, and fast technology. PMID:22422533

Wang, Hongwu; Liu, Yanqing; Wei, Shoulian; Yan, Zijun; Jin, Xing



Sorption of Metal Oxoanions by Composite Biosorbents of Waste Material of Brown Seaweeds Ascophyllum nodosum and PAN  

Microsoft Academic Search

Two different composite sorbents of chemically modified dealginaded seaweed Ascophyllum nodosum (DS-2 and DS-3) were used for the selective removal of metal (W, Mo, and V) oxoanions. All experiments were carried out by dynamic column sorption. The effects of the pH, flow rate and the concentration of the accompanying anions in the feed solution were studied. Sorption of tungstate, molybdate

Eva Mištová; Helena Parschová; Lud?k Jelínek; Zd?n?k Mat?jka; Ferdinand Šebesta



Improved process for the preparation of fiber-reinforced ceramic composites by chemical vapor deposition  


A specially designed apparatus provides a steep thermal gradient across the thickness of fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively from the hot surface of the fibrous preform toward the cold surface. Such deposition prevents the surface of the fibrous preform from becoming plugged. As a result thereof, the flow of reactant matrix gases into the uninfiltrated (undeposited) portion of the fibrous preform occurs throughout the deposition process. The progressive and continuous deposition of ceramic matrix within the fibrous preform provides for a significant reduction in process time over known chemical vapor deposition processes.

Lackey, W.J. Jr.; Caputo, A.J.



Preparation of ZrC nano-particles reinforced amorphous carbon composite coating by atmospheric pressure chemical vapor deposition  

Microsoft Academic Search

To eliminate cracks caused by thermal expansion mismatch between ZrC coating and carbon–carbon composites, a kind of ZrC\\/C composite coating was designed as an interlayer. The atmospheric pressure chemical vapor deposition was used as a method to achieve co-deposition of ZrC and C from ZrCl4–C3H6–H2–Ar source. Zirconium tetrachloride (ZrCl4) powder carrier was especially made to control accurately the flow rate.

W. Sun; X. Xiong; B. Y. Huang; G. D. Li; H. B. Zhang; P. Xiao; Z. K. Chen; X. L. Zheng



Active metal-matrix composites with embedded smart materials by ultrasonic additive manufacturing  

Microsoft Academic Search

This paper presents the development of active aluminum-matrix composites manufactured by Ultrasonic Additive Manufacturing (UAM), an emerging rapid prototyping process based on ultrasonic metal welding. Composites created through this process experience temperatures as low as 25 °C during fabrication, in contrast to current metal-matrix fabrication processes which require temperatures of 500 °C and above. UAM thus provides unprecedented opportunities to

Ryan Hahnlen; Marcelo J. Dapino



Dynamic mechanical properties of composite materials on the base polyethylene and thermal expanded graphite  

NASA Astrophysics Data System (ADS)

The dynamic mechanical and relaxation properties of composite materials are studied. The thermal expanded graphite content is varied from 0 to 1 volume fraction over temperature range from - 180 to 80 C. The graphite is shown to improve the elastic characteristics of composite materials. It is found out that the spatial structures, created by graphite particles, render a significant influence on processes of mechanical relaxation, occurring in polyethylene and composite materials.

Semko, I. S.; Chernysh, I. G.; Svintsitskij, N. I.



Phospholipid content and composition of human meningiomas  

Microsoft Academic Search

The content and distribution of phospholipids, as well as their fatty acid composition, were studied in 16 human meningiomas\\u000a in comparison with normal leptomeninges.\\u000a \\u000a The total phospholipid content of tumors (expressed as organic phosphorus\\/mg DNA) was similar to that of the tissue from which\\u000a they originated. The same phospholipid classes were present in both tissues, but with a different pattern:

L. Riboni; R. Ghidoni; S. Sonnino; F. Omodeo-Salè; S. M. Gaini; B. Berra



Fabrication of tin-carbon composite anode material by electrospinning and electrostatic spray deposition for lithium rechargeable battery  

NASA Astrophysics Data System (ADS)

Metallic Sn-C composites were prepared by using electrospinning and electrostatic spray deposition (ESD). Morphology of the material prepared by these methods can be controlled by changing the experimental conditions such as the flow rate, voltage, composition of precursor solutions. Influence of the morphology on the electrochemical performance for the same composite was studied. Composite fibers prepared by electrospinning and porous films by ESD were characterized using X ray Diffraction, Transmission Electron Microscopy and Electrochemical characterization. Both the fibers and the porous composite films showed good performance compared to the tin nanopowder based anodes. Capacities of 760mAh/g and 686 mAh/g were obtained for Sn@C-hollow carbon nanofibers and Sn-C porous films, respectively.

Dhanabalan, Abirami; Yu, Yan; Li, Xifei; Bechtold, Kevin; Maier, Joachim; Wang, Chunlei



Left Handed Materials Using Magnetic Composites.  

National Technical Information Service (NTIS)

A left-handed composite material which includes a mixture of a ferromagnetic material and a dielectric material. The direction of magnetization of the ferromagnetic material, and its volume fraction are controlled such that the composite material exhibits...

J. Q. Xiao S. T. Chui



Carbon materials for chemical capacitive energy storage.  


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

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



Thermal Shock Properties of a 2D-C/SiC Composite Prepared by Chemical Vapor Infiltration  

NASA Astrophysics Data System (ADS)

The thermal shock properties of a two-dimensional carbon fiber-reinforced silicon carbide composite with a multilayered self-healing coating (2D-C/SiC) were investigated in air. The composite was prepared by low-pressure chemical vapor infiltration. 2D-C/SiC specimens were thermally shocked for different cycles between 900 and 300 °C. The thermal shock resistance was characterized by residual tensile properties and mass variation. The change of the surface morphology and microstructural evolution of the composite were examined by a scanning electron microscope. In addition, the phase evolution on the surfaces was identified using an X-ray diffractometer. It is found that the composite retains its tensile strength within 20 thermal shock cycles. However, the modulus of 2D-C/SiC decreases gradually with increasing thermal shock cycles. Extensive pullout of fibers on the fractured surface and peeling off of the coating suggest that the damage caused by the thermal shock involves weakening of the bonding strength of coating/composite and fiber/matrix. In addition, the carbon fibers in the near-surface zone were oxidized through the matrix cracks, and the fiber/matrix interfaces delaminated when the composite was subjected to a larger number of thermal shock cycles.

Zhang, Chengyu; Wang, Xuanwei; Wang, Bo; Liu, Yongsheng; Han, Dong; Qiao, Shengru; Guo, Yong



Bullets fragments identification by comparison of their chemical composition obtained using instrumental neutron activation analysis  

Microsoft Academic Search

Bullets found in crime scenes are usually compared by examination of the rifling impressions produced in the barrel of the questioned firearm. When, however, a bullet is fragmented or highly deformed, the comparison of rifling micro striations cannot be performed, and the only way two compare two or more bullets is by a match of their chemical analysis. In spite

Antioco Franco Sedda; Gabriele Rossi



Compositional, optoelectronic and structural properties of amorphous silicon-nitrogen alloys deposited by plasma enhanced chemical vapor deposition  

Microsoft Academic Search

High quality amorphous silicon nitrogen films with energy gap in the range of 1.9–3.2 eV have been deposited by plasma enhanced chemical vapor deposition in silane and ammonia gas mixtures. Compositional, structural, electrical and optical properties have been investigated revealing good semiconducting features comparable to those of amorphous silicon-carbon films. Advantages such as high deposition rate have been observed making

F. Giorgis; P. Rava; R. Galloni; R. Rizzoli; C. Summonte; G. Crovini; F. Demichelis; C. F. Pirri; E. Tresso; V. Rigato



Studies on potato nutrition III. Chemical composition and uptake of nutrients by kern county potatoes  

Microsoft Academic Search

Summary Comparisons were made on growth and on dry matter, nitrogen,  phosphoric acid, and potash content of the potatoes grown at four different fertilizer levels during 1945 and 1946.\\u000a \\u000a Nitrogen content of plants and tubers was increased by nitrogen fertilization during the early stages of growth but this was\\u000a not true at maturity.\\u000a \\u000a \\u000a \\u000a Nitrogen, phosphoric acid, and potash greatly decreased per

O. A. Lorenz; O. A. LOREZ



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

Microsoft Academic Search

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 25mgl?1 of Cu(II) in aqueous solution, at pH 5.3, leading to a maximum uptake capacity of ?13

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



Effect of chemical composition of intergranular glass on superplastic compressive deformation of ?-silicon nitride  

Microsoft Academic Search

The effect of chemical composition of Y2O3–Al2O3–SiO2-based intergranular glass on superplastic deformation of ?-Si3N4 was studied by compression tests at 1873K. All hot isostatically pressed Si3N4 materials had essentially the same microstructure and the same amount of glass phase, which was different in composition only. The relation between flow stress and glass composition qualitatively corresponded to the effect of chemical

E. Narimatsu; Y. Shinoda; T. Akatsu; F. Wakai



TECHNICAL NOTE: Fabrication of multiferroic composite actuator material by combining superelastic TiNi filler and a magnetostrictive Ni matrix  

NASA Astrophysics Data System (ADS)

This research aims to design and verify a new magnetically driven multiferroic composite actuator material which is characterized by large strain and a rapid response speed. The composite actuator material is designed to consist of a magnetostrictive Ni matrix and superelastic TiNi alloy fiber fillers whose volume fraction was changed. The spark plasma sintering (SPS) method which is characterized by short time and low temperature processing was used to join these two different material elements. Cross-sectional observation by optical micrograph, mechanical compression tests, and magnetostriction measurements were carried out to verify the perfection of the adhesion state of the TiNi filler and nickel matrix as well as the amplification effect of magnetostriction. As the experimental result, the amplification effect of about a maximum of 1.5 times magnetostriction was verified in the fabricated composite actuator.

Hasegawa, Masanobu; Asano, Takahiro; Hashimoto, Kenji; Lee, Gyu Chang; Park, Young Chul; Okazaki, Teiko; Furuya, Yasubumi



Abrasive rolling effects on material removal and surface finish in chemical mechanical polishing analyzed by molecular dynamics simulation  

Microsoft Academic Search

In an abrasive chemical mechanical polishing (CMP) process, materials were considered to be removed by abrasive sliding and rolling. Abrasive sliding has been investigated by many molecular dynamics (MD) studies; while abrasive rolling was usually considered to be negligible and therefore was rarely investigated. In this paper, an MD simulation was used to study the effects of abrasive rolling on

Lina Si; Dan Guo; Jianbin Luo; Xinchun Lu; Guoxin Xie



Aerosol chemical composition over Istanbul.  


This study examines the chemical composition of aerosols over the Greater Istanbul Area. To achieve this 325 (PM(10)) aerosol samples were collected over Bosphorus from November 2007 to June 2009 and were analysed for the main ions, trace metals, water-soluble organic carbon (WSOC), organic (OC) and elemental carbon (EC). PM(10) levels were found to be in good agreement with those measured by the Istanbul Municipality air quality network, indicating that the sampling site is representative of the Greater Istanbul Area. The main ions measured in the PM(10) samples were Na(+), Ca(2+) and non-sea-salt sulphates (nss-SO(4)(2-)). On average, 31% of Ca(2+) was found to be associated with carbonates. Trace elements related to human activities (as Pb, V, Cd and Ni) obtained peak values during winter due to domestic heating, whereas natural origin elements like Al, Fe and Mn peaked during the spring period due to dust transport from Northern Africa. Organic carbon was found to be mostly primary and elemental carbon was strongly linked to fuel oil combustion and traffic. Both OC and EC concentrations increased during winter due to domestic heating, while the higher WSOC to OC ratio during summer can be mostly attributed to the presence of secondary, oxidised and more soluble organics. Factor analysis identified six components/sources for aerosol species in PM(10), namely traffic/industrial, crustal, sea-salt, fuel-oil combustion, secondary and ammonium sulfate. PMID:20304466

Theodosi, C; Im, U; Bougiatioti, A; Zarmpas, P; Yenigun, O; Mihalopoulos, N



Chemical composition of Hanford Tank SY-102  

SciTech Connect

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.

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



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

Microsoft Academic Search

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

Patrick Landais; Aïcha Rochdi; Claude Largeau; Sylvie Derenne



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

Microsoft Academic Search

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

Jinsong Leng; Anand Asundi



Chemical composition of heavy coker gasoil and products from its adsorptive treatment  

SciTech Connect

The expansion of electrode coke production by delayed coking has led to an increase in the amounts of light and heavy gasoils in the refinery balance. Uses chromatographic separation and mass spectrometry to investigate the hydrocarbon composition of the heavy gasoil from delayed coking of a thermally cracked distillate feed, produced from a mixture of medium-sulfur crudes. Examines the products obtained from this coker gasoil by adsorptive treatment to upgrade the material. Shows that delayed coker gasoils, with respect to chemical composition, are unique products from petroleum processing. Finds that by treatment in a moving bed by aluminosilica adsorbent, with proper adjustment of the ratio of adsorbent to feedstock, practically resin-free, highly aromatic oils can be obtained, differing in the contents of individual types of polycyclic aromatic hydrocarbons, with about 55% of such hydrocarbons in the desorbed oil and about 30% in the oil that is the principal product.

Alekhina, N.I.; Levinson, S.Z.; Mikhailov, I.A.



Highly bioactive silver and silver\\/titania composite films grown by chemical vapour deposition  

Microsoft Academic Search

This paper describes how photocatalytically active films of TiO2, grown by thermal CVD, may be functionally and structurally modified by deposition of nano-structured silver via a novel flame assisted CVD process. The resulting composite films are shown to be highly durable, highly photocatalytically active and are also shown to possess strong antibacterial behaviour.The deposition control, arising from the described approach,

L. A. Brook; P. Evans; H. A. Foster; M. E. Pemble; A. Steele; D. W. Sheel; H. M. Yates



Determination of the chemical composition distribution of copolymers of styrene and butadiene by gradient polymer elution chromatography  

Microsoft Academic Search

In order to determine the chemical composition distribution (CCD) of styrene-butadiene copolymers, gradient polymer elution chromatography has been performed. The separation is mainly based on differences in solubility among the copolymer molecules with different chemical composition. The solubility of a copolymer is dependent on the following parameters: temperature, type of solvent\\/non-solvent mixture, molecular mass of the polymer and the chemical

P. J. C. H. Cools; F. Maesen; B. Klumperman; A. M. van Herk; A. L. German



Analysis of Fatty Acid content and composition in microalgae.  


A method to determine the content and composition of total fatty acids present in microalgae is described. Fatty acids are a major constituent of microalgal biomass. These fatty acids can be present in different acyl-lipid classes. Especially the fatty acids present in triacylglycerol (TAG) are of commercial interest, because they can be used for production of transportation fuels, bulk chemicals, nutraceuticals (?-3 fatty acids), and food commodities. To develop commercial applications, reliable analytical methods for quantification of fatty acid content and composition are needed. Microalgae are single cells surrounded by a rigid cell wall. A fatty acid analysis method should provide sufficient cell disruption to liberate all acyl lipids and the extraction procedure used should be able to extract all acyl lipid classes. With the method presented here all fatty acids present in microalgae can be accurately and reproducibly identified and quantified using small amounts of sample (5 mg) independent of their chain length, degree of unsaturation, or the lipid class they are part of. This method does not provide information about the relative abundance of different lipid classes, but can be extended to separate lipid classes from each other. The method is based on a sequence of mechanical cell disruption, solvent based lipid extraction, transesterification of fatty acids to fatty acid methyl esters (FAMEs), and quantification and identification of FAMEs using gas chromatography (GC-FID). A TAG internal standard (tripentadecanoin) is added prior to the analytical procedure to correct for losses during extraction and incomplete transesterification. PMID:24121679

Breuer, Guido; Evers, Wendy A C; de Vree, Jeroen H; Kleinegris, Dorinde M M; Martens, Dirk E; Wijffels, René H; Lamers, Packo P



Using simultaneous deposition and rapid growth to produce nanostructured composite films of AlN/TiN by chemical vapor deposition  

SciTech Connect

Brittleness has been the major obstacle in using ceramics. Previous research has shown, however, that ceramic materials that have small grain size show plasticity. The authors therefore propose two methods to produce nanostructured ceramic films by chemical vapor deposition (CVD): (1) high-speed deposition and (2) simultaneous deposition of insoluble materials (contained in a mixture of insoluble solids). These methods were successfully applied to aluminum nitride/titanium nitride (AlN/TiN) films produced by CVD. The AlN/TiN nanostructured composite films were synthesized by atmospheric-pressure CVD (APCVD), using aluminum chloride (AlCl{sub 3}), titanium chloride (TiCl{sub 4}), and ammonia (NH{sub 3}) as reactant gases at temperatures ranging from 923 to 1123 K in a horizontal tubular reactor. For the high-speed deposition strategy, the authors obtained growth rates as high as 1.2 mm/h. Using either method, they were able to attain AlN/TiN composite films that had a grain size of 8 nm (AlN crystals) and 6 nm (TiN crystals), showing that these methods are effective in producing nanostructured composite films by CVD. Measurements of the fracture toughness of the prepared materials indicated that these strategies can be used to improve the ductility of ceramics.

Liu, Y.J.; Egashira, Yasuyuki; Komiyama, Hiroshi [Univ. of Tokyo (Japan). Dept. of Chemical System Engineering; Kim, H.J. [Toyohashi Univ. of Technology (Japan). Dept. of Ecological Engineering; Kimura, Hisamichi [Tohoku Univ., Sendai (Japan). Inst. of Materials Research



Physical chemical properties of polyimide palladium nano - composite membranes  

Microsoft Academic Search

Polyimide polymer membranes posses' exceptional physical - chemical properties including excellent stability at relatively high temperatures (? 400°C), superior mechanical properties, and are highly resistant to various chemicals. Palladium is well known for its unique physical - chemical interactions with hydrogen. Interest in metal polymer composites can be attributed to the drive to produce a material with the savings in

Patrick Ndungu; Olushola Adeniyi; Leslie Petrik; Alexander Nechaev



The Chemical Composition of iota Herculis, .  

National Technical Information Service (NTIS)

The chemical composition of the sharp-lined B3 V star iota Her has been determined by a model-atmosphere technique. All elements considered in this analysis seem to have solar-type abundances. The effective temperature determined for this star by the crit...

G. J. Peters L. H. Aller



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.  


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 (IC(50) = 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

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



The relationship of argon retentivity and chemical composition of hornblende  

SciTech Connect

K-Ar ages of 26 hornblende separates from Connemara, western Ireland do not show any correlation with the chemical composition of the hornblendes, including their iron contents. It is suggested that this is the usual pattern as there are only rare reports of compositional control of K-Ar ages.

Leake, B.E.; Farrow, C.M. (Univ. of Glasgow (Scotland)); Elias, E.M. (Univ. of Mosul (Iraq))



In vitro release kinetics and physical, chemical and mechanical characterization of a POVIAC®/CaCO3/HAP-200 composite.  


Coralline calcium-hydroxyapatite and calcium carbonate from Porites Porites coral were added to a polymeric matrix based on polyvinyl acetate (POVIAC(®)), to obtain a novel bone substitute composite as well as a system for the controlled drug (cephalexin) release. Composite samples with different compositions were characterized by physical-chemical and mechanical methods. Furthermore, the in vitro release profile of cephalexin and the kinetic behavior of its release from these composites were analyzed by appropriate mathematical models. It was shown that there is no chemical interaction between the inorganic filler and the polymer matrix, each conserving the original properties of the raw materials. The compressive mechanical strength and Young modulus of the composite with 17.5% of POVIAC(®), has better mechanical properties than those of cancellous bone. The variation of POVIAC(®) content can affect the cephalexin release kinetic in the composite. The cephalexin release mechanism from the composites can be considered as the result of the joint contribution of a prevailing Fickian diffusion and of polymer chain relaxation. It was also demonstrated that cephalexin is occluded inside the composites and not on their surface. PMID:22201028

Aragón, Javier; González, Ramón; Fuentes, Gastón; Palin, Luca; Croce, Gianluca; Viterbo, Davide



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


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.

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



Chemical composition of burnt smell caused by accidental fires: environmental contaminants.  


The chemical composition of the odors typical of fires has recently been deciphered. Basically the constituents are mixtures of acetophenone, benzyl alcohol, hydroxylated derivatives of benzaldehyde, methoxylated and/or alkylated phenols and naphthalene. This finding makes it possible to develop objective, practical analytic measurement methods for the burnt smell as a contribution to improving fire damage assessment and remediation monitoring. With the aid of an artificially produced burnt smell and a panel of testers the odor detection threshold of a test mixture was determined olfactometrically to 2 ?g m?³. Using a defined burnt-smell atmosphere in a test chamber, analytical methods with active sampling, the adsorbents XAD 7 and TENAX TA, and GC/MS measurement were then optimized and tested with a view to being able to carry out sensitive quantitative measurement of burnt smells. A further practical method with particular application to the qualitative characterization of this odor is based on the use of a new SPME (solid-phase microextraction) field sampler with DVB/CAR/PDMS (divinylbenzene/Carboxen™/polydimethylsiloxane) fibers. PMID:20947130

Heitmann, K; Wichmann, H; Bahadir, M; Gunschera, J; Schulz, N; Salthammer, T



New strong cement materials: chemically bonded ceramics  

Microsoft Academic Search

New cements developed in recent years have strengths that are greater by an order of magnitude than those of conventional hydraulic cements. These low-temperature materials, whose strengths approach those of many traditional high-temperature ceramics, are termed chemically bonded ceramics. The different routes to generating strong cementitious materials, including warm pressing, chemical modification, high-shear mixing with polymer additions, and the making




Nanoparticulate cerium dioxide and cerium dioxide-titanium dioxide composite thin films on glass by aerosol assisted chemical vapour deposition  

NASA Astrophysics Data System (ADS)

Two series of composite thin films were deposited on glass by aerosol assisted chemical vapour deposition (AACVD)—nanoparticulate cerium dioxide and nanoparticulate cerium dioxide embedded in a titanium dioxide matrix. The films were analysed by a range of techniques including UV-visible absorption spectroscopy, X-ray diffraction, scanning electron microscopy and energy dispersive analysis by X-rays. The AACVD prepared films showed the functional properties of photocatalysis and super-hydrophilicity. The CeO 2 nanoparticle thin films displaying photocatalysis and photo-induced hydrophilicity almost comparable to that of anatase titania.

Qureshi, Uzma; Dunnill, Charles W.; Parkin, Ivan P.



Effect of film composition on the performance of interdigitated electrode methods used for chemically amplified photoresist characterization: methods for analyzing photoresist materials containing base quencher  

NASA Astrophysics Data System (ADS)

Previously, a method which utilizes interdigitated electrode (IDE) sensors to collect capacitance versus exposure dose data for thin films containing a photoacid generator (PAG) and polymer and subsequently calculate the Dill C photoreaction rate constant for the photoacid generator has been presented. This paper discusses a method for extending such IDE methods to calculate the Dill C rate constant for a photoacid generator in a film containing a polymer, photoacid generator, and base quencher. This three component formulation more closely resembles the composition of commercial chemically amplified photoresists. It is shown that by using a data normalization approach, the IDE data can be successfully analyzed to compute accurate Dill C values for a PAG in the presence of base quencher and to estimate the concentration of base quencher in the film. The technique also thus allows for measurement of the impact of the presence of base quencher on the photoreaction rate constant of the photoacid generator.

Berger, Cody; Henderson, Clifford L.



Cell wall fermentation kinetics are impacted more by lignin content and ferulate cross-linking than by lignin composition  

Technology Transfer Automated Retrieval System (TEKTRAN)

BACKGROUND: We used a biomimetic model system to ascertain how reductions in ferulate-lignin cross-linking and shifts in lignin composition influence ruminal cell wall fermentation. Primary walls from maize cell suspensions with normal or reduced feruloylation were artificially lignified with variou...


Manufacturing technology of the composite materials: nanocrystalline material - polymer type  

Microsoft Academic Search

Purpose: This paper presents the material and technological solution which makes it possible to obtain the nanocrystalline, ferromagnetic powder material of Fe73.5Cu1Nb3Si13.5B9 alloy after its thermal nanocrystallization with the succeeding high-energy milling. Another aspect was to develop the technology to obtain the nanocrystalline composite materials made by binding the obtained powder material with the high density low- pressures polyethylene (PEHD)

B. Zi?bowicz; D. Szewieczek; L. A. Dobrza?ski


Radiopacity of experimental composite resins containing radiopaque materials.  


This study aimed to investigate the relationship between the radiopacity of an experimental light-cured composite resin and the amount and type of its radiopaque material: Ti, SrCO3, ZrO2, BaSO4, or Bi2O3. Radiopacity of each material was evaluated in terms of aluminum equivalent thickness using an aluminum step wedge. Then, the half-value layer thickness of the experimental composite resin, which had an aluminium equivalent thickness of 1 mm, was evaluated. It was found that the effects of elemental composition were not identical when evaluated in terms of aluminum equivalent thickness and by half-value layer. Nevertheless, both measurement methods indicated that radiopacity increased with increase in radiopaque material content as well as increase in atomic number of the element. PMID:16279720

Aoyagi, Yujin; Takahashi, Hidekazu; Iwasaki, Naohiko; Honda, Ei-ichi; Kurabayashi, Toru



Analysis of Marine Biota for Chemical Warfare Materials by Means of a Gas Chromatography/Mass Spectrometer System.  

National Technical Information Service (NTIS)

The U.S. Army Edgewood Chemical Biological Center's (ECBC) Directorate of Program Integration Environmental Monitoring Branch developed a procedure and conducted a Method Detection Limit (MDL) study for the analysis of Chemical Warfare Materials (CWM) in ...

B. E. Dusick J. L. Schwarz M. L. Avila



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.  


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

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



Chemical compositions of subway particles in Seoul, Korea determined by a quantitative single particle analysis.  


A novel single particle analytical technique, low-Z particle electron probe X-ray microanalysis, was applied to characterize seasonal subway samples collected at a subway station in Seoul, Korea. For all 8 samples collected twice in each season, 4 major types of subway particles, based on their chemical compositions, are significantly encountered: Fe-containing; soil-derived; carbonaceous; and secondary nitrate and/or sulfate particles. Fe-containing particles are generated indoors from wear processes at rail-wheel-brake interfaces while the others may be introduced mostly from the outdoor urban atmosphere. Fe-containing particles are the most frequently encountered with relative abundances in the range of 61-79%. In this study, it is shown that Fe-containing subway particles almost always exist either as partially or fully oxidized forms in underground subway microenvironments. Their relative abundances of Fe-containing particles increase as particle sizes decrease. Relative abundances of Fe-containing particles are higher in morning samples than in afternoon samples because of heavier train traffic in the morning. In the summertime samples, Fe-containing particles are the most abundantly encountered, whereas soil-derived and nitrate/sulfate particles are the least encountered, indicating the air-exchange between indoor and outdoor environments is limited in the summer, owing to the air-conditioning in the subway system. In our work, it was observed that the relative abundances of the particles of outdoor origin vary somewhat among seasonal samples to a lesser degree, reflecting that indoor emission sources predominate. PMID:19174870

Kang, Sunni; Hwang, HeeJin; Park, YooMyung; Kim, HyeKyoung; Ro, Chul-Un



Durability of polymer composite materials  

Microsoft Academic Search

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

Liu Liu



Welds in thermoplastic composite materials  

NASA Astrophysics Data System (ADS)

Welding methods are reviewed that can be effectively used for joining of thermoplastic composites and continuous-fiber thermoplastics. Attention is given to the use of ultrasonic, vibration, hot-plate, resistance, and induction welding techniques. The welding techniques are shown to provide complementary weld qualities for the range of thermoplastic materials that are of interest to industrial and technological applications.

Taylor, N. S.


Chemical constraints on fly ash glass compositions  

SciTech Connect

The major oxide content and mineralogy of 75 European fly ashes were examined, and the major element composition of the glass phase was obtained for each. Correlation of compositional trends with the glass content of the ash was explored. Alkali content was deduced to have a major influence on glass formation, and this in turn could be related to the probable chemistry of clay minerals in the source coals. Maximal glass content corresponded to high aluminum content in the glass, and this is in accordance with the theoretical mechanism of formation of aluminosilicate glasses, in which network-modifying oxides are required to promote tetrahedral coordination of aluminum in glass chain structures. Iron oxide was found to substitute for alkali oxides where the latter were deficient, and some indications of preferred eutectic compositions were found. The work suggests that the proportion of the glass phase in the ash can be predicted from the coal mineralogy and that the utility of a given ash for processing into geopolymers or zeolites is determined by its source. 23 refs., 7 figs., 1 tab.

John H. Brindle; Michael J. McCarthy [University of Dundee, Dundee (United Kingdom). Division of Civil Engineering



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

Microsoft Academic Search

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

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


Variations in the chemical composition of cassava ( Manihot esculenta Crantz) leaves and roots as affected by genotypic and environmental variation.  


The purpose of this study was to assess the quality of cassava cultivars, in terms of cyanogenic potential and composition of macro- and micronutrients, sampled from different locations in rural Mozambique. Total cyanide concentrations in fresh cassava tissues were measured using portable cyanide testing kits, and elemental nutrients were later analyzed from dried plant tissue. Variation in cyanogenic potential and nutrient composition occurred both among cultivars and across locations. The majority of cultivars contained >100 ppm total cyanide, fresh weight, and are therefore considered to be dangerously poisonous unless adequately processed before consumption. Leaf cyanogenic and nutrient content varied with plant water status, estimated using carbon isotope discrimination (?(13)C). The colonization of roots of all cultivars by arbuscular mycorrhizal fungi was also quantified and found to be high, indicating that mycorrhizas could play a key role in plant nutrient acquisition in these low-input farming systems. PMID:22515684

Burns, Anna Elizabeth; Gleadow, Roslyn Margaret; Zacarias, Anabela M; Cuambe, Constantino Estevão; Miller, Rebecca Elizabeth; Cavagnaro, Timothy Richard



Delicate refinement of surface nanotopography by adjusting TiO2 coating chemical composition for enhanced interfacial biocompatibility.  


Surface topography and chemistry have significant influences on the biological performance of biomedical implants. Our aim is to produce an implant surface with favorable biological properties by dual modification of surface chemistry and topography in one single simple process. In this study, because of its chemical stability, excellent corrosion resistance, and biocompatibility, titanium oxide (TiO2) was chosen to coat the biomedical Ti alloy implants. Biocompatible elements (niobium (Nb) and silicon (Si)) were introduced into TiO2 matrix to change the surface chemical composition and tailor the thermophysical properties, which in turn leads to the generation of topographical features under specific thermal history of plasma spraying. Results demonstrated that introduction of Nb2O5 resulted in the formation of Ti0.95Nb0.95O4 solid solution and led to the generation of nanoplate network structures on the composite coating surface. By contrast, the addition of SiO2 resulted in a hairy nanostructure and coexistence of rutile and quartz phases in the coating. Additionally, the introduction of Nb2O5 enhanced the corrosion resistance of TiO2 coating, whereas SiO2 did not exert much effect on the corrosion behaviors. Compared to the TiO2 coating, TiO2 coating doped with Nb2O5 enhanced primary human osteoblast adhesion and promoted cell proliferation, whereas TiO2 coatings with SiO2 were inferior in their bioactivity, compared to TiO2 coatings. Our results suggest that the incorporation of Nb2O5 can enhance the biological performance of TiO2 coatings by changing the surface chemical composition and nanotopgraphy, suggesting its potential use in modification of biomedical TiO2 coatings in orthopedic applications. PMID:23957368

Zhao, Xiaobing; Wang, Guocheng; Zheng, Hai; Lu, Zufu; Zhong, Xia; Cheng, Xingbao; Zreiqat, Hala



High indium content InGaN films grown by pulsed laser deposition using a dual-compositing target.  


High indium compositions InGaN films were grown on sapphires using low temperature pulse laser deposition (PLD) with a dual-compositing target. This target was used to overcome the obstacle in the InGaN growth by PLD due to the difficulty of target preparation, and provided a co-deposition reaction, where InGaN grains generated from the indium and GaN vapors deposit on sapphire surface and then act as nucleation seeds to promote further InGaN growth. The effects of co-deposition on growth mechanisms, surface morphology, and electrical properties of films were thoroughly investigated and the results clearly show promise for the development of high indium InGaN films using PLD technique with dual-compositing targets. PMID:22772213

Shen, Kun-Ching; Wang, Tzu-Yu; Wuu, Dong-Sing; Horng, Ray-Hua



[Changes in chemical composition of tomatoes during processing].  


The influences of processing conditions and composition on chemical changes during thermal processing of tomatoes were investigated. During the Cold and Hot Break process pectin is degraded to different extents. Due to the thermal impact at first cyclization of glutamine to pyroglutamic acid takes place. At higher dry weight contents and during drying processes Amadori compounds and browning can be detected. The reaction products formed during thermal processing can be analysed by amino acid analysis and-after proper derivatization-by capillary gas chromatography. PMID:8711954

Schräder, I; Eichner, K



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


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

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



Fabrication of a nanostructured gold-polymer composite material  

NASA Astrophysics Data System (ADS)

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.

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



Materials Aspects of Fiber-Reinforced Polymer Composites in Infrastructure.  

National Technical Information Service (NTIS)

This paper provides a review of the technical literature pertaining to materials aspects of fiber-reinforced polymer (FRP) composites in infrastructural and other civil engineering applications. The main focus is placed upon the durability, chemical and m...

J. W. Chin



A Grammatical Approach for Customization of Laminated Composite Materials  

Microsoft Academic Search

The wide range of properties covered by the manufacturable fiber—matrix combinations of composite materials, along with their directional property characteristics, provides designers with material selection flexibility during designing composite material products. Meeting multiple property goals, however, complicates the design process as both the composite material selection and the component shape formation becomes intricate with the multiple loading conditions, which may

Soumitra Nandi; Zahed Siddique; M. Cengiz Altan



Carbon nanotube\\/polyaniline composite as anode material for microbial fuel cells  

Microsoft Academic Search

A carbon nanotube (CNT)\\/polyaniline (PANI) composite is evaluated as an anode material for high-power microbial fuel cells (MFCs). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) are employed to characterize the chemical composition and morphology of plain PANI and the CNT\\/PANI composite. The electrocatalytic behaviour of the composite anode is investigated by means of electrochemical impedance spectroscopy (EIS)

Yan Qiao; Chang Ming Li; Shu-Juan Bao; Qiao-Liang Bao



Effect of Spherical Silica on the Molding and Properties of Cellulose\\/Plastic Composite with High Cellulose Content  

Microsoft Academic Search

It is important to utilize reinforcement by fibers in wood plastic composites (WPC). However, when a thermoplastic polymer is mixed with fibrous wood material, the melt fluidity of the mixture usually decreases and its fabrication becomes difficult. This tendency is pronounced for the composite with a high cellulose content. In this study, the effects of added fly ash, which is

Hirokazu Ito; Hidehiro Hattori; Shota Hirai; Tadashi Okamoto; Masahiro Takatani



Nonmetallic materials and composites at low temperatures  

Microsoft Academic Search

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

G. Hartwig; D. Evans



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

SciTech Connect

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.

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



Isolation, purification and chemical composition of maize root cap slime  

Microsoft Academic Search

Summary The total root exudate isolated axenically from roots is shown to constitute an extremely heterogenous population of particulate and soluble material. Differences in protein and total sugars contents, and neutral sugar composition throughout stages of total root exudate purification are reported. The importance of controlled collection and purification conditions to ensure valid analysis and composition of purified maize root

Annie Chaboud



Sequential processing for content-based retrieval of composite objects  

NASA Astrophysics Data System (ADS)

It is becoming increasingly important for multimedia databases to provide capabilities for content-based retrieval of composite objects. Composite objects consist of several simple objects which have feature, spatial, temporal, semantic attributes, and spatial and temporal relationships between them. A content-based composite object query is satisfied by evaluating a program of content-based rules (i.e., color, texture), spatial and temporal rules (i.e., east, west), fuzzy conjunctions (i.e., appears similar AND is spatially near) and database lookups (i.e., semantics). We propose a new sequential processing method for efficiently computing content-based queries of composite objects. The proposed method evaluates the composite object queries by (1) defining an efficient ordering of the sub-goals of the query, which involve spatial, temporal, content-based and fuzzy rules, (2) developing a query block management strategy for generating, evaluating, and caching intermediate sub-goal results, and (3) conducting a best-first dynamic programming-based search with intelligent back-tracking. The method is guaranteed to find the optimal answer to the query and reduces the query time by avoiding the exploration of unlikely candidates.

Li, Chung-Sheng; Smith, John R.; Bergman, Lawrence D.; Castelli, Vittorio



Compositional and structural properties of deuterated plasma enhanced chemical vapour deposited silicon-carbon alloys  

Microsoft Academic Search

Hydrogenated and deuterated amorphous silicon carbon films were prepared by plasma enhanced chemical vapour deposition (PECVD) starting from silane and deuterated methane gas mixtures. The gas percentages was varied in order to produce films with different carbon and silicon content. The elemental composition was determined by Rutherford backscattering and elastic recoil detection analysis and the bonding structure by infrared spectroscopy.

L. Calcagno; F. Giorgis; A. Makthari; P. Musumeci; F. Pirri



Deposition of microcrystalline silicon prepared by hot-wire chemical-vapor deposition: The influence of the deposition parameters on the material properties and solar cell performance  

NASA Astrophysics Data System (ADS)

Microcrystalline silicon (?c-Si:H) of superior quality can be prepared using the hot-wire chemical-vapor deposition method (HWCVD). At a low substrate temperature (TS) of 185 °C excellent material properties and solar cell performance were obtained with spin densities of 6×1015 cm-3 and solar cell efficiencies up to 9.4%, respectively. In this study we have systematically investigated the influence of various deposition parameters on the deposition rate and the material properties. For this purpose, thin films and solar cells were prepared at specific substrate and filament temperatures and deposition pressures (pD), covering the complete range from amorphous to highly crystalline material by adjusting the silane concentration. The influence of these deposition parameters on the chemical reactions at the filament and in the gas phase qualitatively explains the behavior of the structural composition and the formation of defects. In particular, we propose that the deposition rate is determined by the production of reactive species at the filament and a particular atomic-hydrogen-to-silicon ratio is found at the microcrystalline/amorphous transition. The structural, optical, and electronic properties were studied using Raman and infrared spectroscopies, optical-absorption measurements, electron-spin resonance, and dark and photoconductivities. These experiments show that higher TS and pD lead to a deterioration of the material quality, i.e., much higher defect densities, oxygen contaminations, and SiH absorption at 2100 cm-1. Similar to plasma enhanced chemical-vapor deposition material, ?c-Si:H solar cells prepared with HW i layers show increasing open circuit voltages (Voc) with increasing silane concentration and best performance is achieved near the transition to amorphous growth. Such solar cells prepared at low TS exhibit very high Voc up to 600 mV and fill factors above 70% with i layers prepared by HWCVD.

Klein, Stefan; Finger, Friedhelm; Carius, Reinhard; Stutzmann, Martin



Long-term sorption of halogenated organic chemicals by aquifer material. 2. Intraparticle diffusion  

Microsoft Academic Search

The rate of sorptive uptake of tetrachloroethene (PCE) and 1,2,4,5-tetrachlorobenzene (TeCB) was studied on sandy aquifer material from Borden, ON, by use of a batch methodology designed to accurately measure sorption over long equilibration periods. Measured rates of uptake were interpreted with an intraparticle diffusion model and diffusive rate constants were determined for different size fractions of the Borden solids

William P. Ball; Paul V. Roberts



Chemical composition of essential oil from Calligonum polygonoides Linn.  


The essential oil from air dried buds and roots of Calligonum polygonoides Linn., has been extracted from dry steam distillation and analysed for chemical composition by gas chromatography-mass spectrometry. In total, 27 and 10 compounds were analysed qualitatively and quantitatively, accounting for 68.42% and 82.12% total contents of the essential oils of buds and roots, respectively. It contains a complex mixture of terpenoids, hydrocarbons, phenolic compounds, acid derivatives and ketones. The main component of essential oil was ethyl homovanillate (11.79%) in buds and drimenol (29.42%) in roots. PMID:22574752

Samejo, Muhammad Qasim; Memon, Shahabuddin; Bhanger, Muhammad Iqbal; Khan, Khalid Mohammed



IR spectroscopic study of the chemical composition of epiphytic lichens  

NASA Astrophysics Data System (ADS)

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.

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



The study of chemical composition and elemental mappings of colored overglaze porcelain fired in Qing Dynasty by micro-X-ray fluorescence  

Microsoft Academic Search

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

Cheng Lin; Li Meitian; Kim Youshi; Fan Changsheng; Wang Shanghai; Pan Qiuli; Liu Zhiguo; Li Rongwu



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

Microsoft Academic Search

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

Cong Tam Nguyen



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

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

Leonardo Velasco; Christian Möllers; Heiko C. Becker



Conformational composition of cyclopentadienylphosphine investigated by microwave spectroscopy and quantum chemical calculations.  


The properties of cyclopentadienylphosphine have been investigated by means of Stark-modulation microwave spectroscopy and quantum chemical calculations at the MP2/aug-cc-pVTZ, B3LYP/6-311++G(d,p), and G3 levels of theory. Spectra attributable to two rotamers denoted conformers I and II have been assigned. Conformer I has a symmetry plane (Cs symmetry) consisting of the bisectors of the cyclopentadiene ring and of the phosphino group with the lone electron pair of phosphorus pointing toward the carbon ring. In conformer II, the phosphino group is rotated approximately 120 degrees out of this plane. Relative intensity measurements have been made, and it was found that conformer II is more stable than I by 1.3(4) kJ/mol. The preferred conformer represents a borderline case of intramolecular hydrogen bond stabilization. The experimental and MP2/ aug-cc-pVTZ rotational constants differ by several percent, which indicates that the aug-cc-pVTZ basis set is not large enough to be able to predict an accurate structure for the two conformers that are close to the equilibrium geometries. 5-Substituted 1,3-cyclopentadienyl derivatives may undergo circumambulatory rearrangements. However, there is no manifestation of this effect in the microwave spectrum of cyclopentadienylphosphine. PMID:16419990

Møllendal, Harald; Cole, George C; Guillemin, Jean-Claude



Colorimetric evaluation of composite materials with different thickness by reflectance spectroscopy  

NASA Astrophysics Data System (ADS)

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.

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



Development of Functional Inorganic Materials by Soft Chemical Process Using Ion-Exchange Reactions  

NASA Astrophysics Data System (ADS)

Our study on soft chemical process using the metal oxide and metal hydroxide nanosheets obtained by exfoliation their layered compounds were reviewed. Ni(OH)2?MnO2 sandwich layered nanostructure can be prepared by layer by-layer stacking of exfoliated manganese oxide nanosheets and nickel hydroxide layers. Manganese oxide nanotubes can be obtained by curling the manganese oxide nanosheets using the cationic surfactants as the template. The layered titanate oriented thin film can be prepared by restacking the titanate nanosheets on a polycrystalline substrate, and transformed to the oriented BaTiO3 and TiO2 thin films by the topotactic structural transformation reactions, respectively. The titanate nanosheets can be transformed anatase-type TiO2 nanocrystals under hydrothermal conditions. The TiO2 nanocrystals are formed by a topotactic structural transformation reaction. The TiO2 nanocrystals prepared by this method expose specific crystal plane on their surfaces, and show high photocatalytic activity and high dye adsorption capacity for high performance dye-sensitized solar cell. A series of layered basic metal salt (LBMS) compounds were prepared by hydrothermal reactions of transition metal hydroxides and organic acids. We succeeded in the exfoliation of these LBMS compounds in alcohol solvents, and obtained the transition metal hydroxide nanosheets for the first time.

Feng, Qi


Polymer composites and porous materials prepared by thermally induced phase separation and polymer-metal hybrid methods  

NASA Astrophysics Data System (ADS)

The primary objective of this research is to investigate the morphological and mechanical properties of composite materials and porous materials prepared by thermally induced phase separation. High melting crystallizable diluents were mixed with polymers so that the phase separation would be induced by the solidification of the diluents upon cooling. Theoretical phase diagrams were calculated using Flory-Huggins solution thermodynamics which show good agreement with the experimental results. Porous materials were prepared by the extraction of the crystallized diluents after cooling the mixtures (hexamethylbenzene/polyethylene and pyrene/polyethylene). Anisotropic structures show strong dependence on the identity of the diluents and the composition of the mixtures. Anisotropic crystal growth of the diluents was studied in terms of thermodynamics and kinetics using DSC, optical microscopy and SEM. Microstructures of the porous materials were explained in terms of supercooling and dendritic solidification. Dual functionality of the crystallizable diluents for composite materials was evaluated using isotactic polypropylene (iPP) and compatible diluents that crystallize upon cooling. The selected diluents form homogeneous mixtures with iPP at high temperature and lower the viscosity (improved processability), which undergo phase separation upon cooling to form solid particles that function as a toughening agent at room temperature. Tensile properties and morphology of the composites showed that organic crystalline particles have the similar effect as rigid particles to increase toughness; de-wetting between the particle and iPP matrix occurs at the early stage of deformation, followed by unhindered plastic flow that consumes significant amount of fracture energy. The effect of the diluents, however, strongly depends on the identity of the diluents that interact with the iPP during solidification step, which was demonstrated by comparing tetrabromobisphenol-A and phthalic anhydride. A simple method to prepare composite surfaces that can change the wettability in response to the temperature change was proposed and evaluated. Composite surfaces prepared by nanoporous alumina templates filled with polymers showed surface morphology and wettability that depend on temperature. This effect is attributed to the significant difference in thermal conductivity and the thermal expansion coefficient between the alumina and the polymers. The reversibility in thermal response depends on the properties of the polymers.

Yoon, Joonsung


Determination of Structure and Composition in Ceramics and Aerospace Materials by Neutron Radiography  

Microsoft Academic Search

Two new species of materials were studied by neutron radiography: lithium-bearing ceramics and glasses, and titanium aluminide alloys. Various types of discontinuities, including voids and bulk density reduction, were detected. Hydrogen absorption by a titanium aluminide alloy was measured as a function of exposure lime, with ‘as received’ and polished samples. The interaction of hydrogen with the metal lattice is

Y. Nir-El; V. Katz; J. Haddad; D. Eliezer



3-D textile reinforcements in composite materials  

SciTech Connect

Laminated composite materials have been used in structural applications since the 1960s. However, their high cost and inability to accommodate fibers in the laminate`s thickness direction greatly reduce their damage tolerance and impact resistance. The second generation of materials--3-D textile reinforced composites--offers significant cost reduction, and by incorporating reinforcement in the thickness direction, dramatically increases damage tolerance and impact resistance. However, methods for predicting mechanical properties of 3-D textile reinforced composite materials tend to be more complex. These materials also have disadvantages--particularly in regard to crimps in the yarns--that require more research. Textile preforms, micro- and macromechanical modeling, manufacturing processes, and characterization all need further development. As researchers overcome these problems, this new generation of composites will emerge as a highly competitive family of materials. This book provides a state-of-the-art account of this promising technology. In it, top experts describe the manufacturing processes, highlight the advantages, identify the main applications, analyze methods for predicting mechanical properties, and detail various reinforcement strategies, including grid structure, knitted fabric composites, and the braiding technique. Armed with the information in this book, readers will be prepared to better exploit the advantages of 3-D textile reinforced composites, overcome its disadvantages, and contribute to the further development of the technology.

Miravete, A. [Univ. of Zaragoza (Spain)



New Initiatives on RR Lyrae Chemical Compositions  

NASA Astrophysics Data System (ADS)

The serendipitous discovery by Preston and colleagues of the neutron-capture-enhanced RR Lyrae variable star TY Gru (a.k.a. CS 22881-071 in the ``HK'' survey of very metal-poor halo stars) has resulted in a growing set of initiatives on the chemical compositions of RR Lyrae stars and their application to broader topics in Galactic halo structure. Here we summarize the main aspects of our work on TY Gru, including a new discussion of our search for possible orbital motion of this star around a putative unseen companion. Then we describe a few of the results of a newly-completed intensive spectroscopic investigation of 10 additional field RR Lyr stars. We finish by outlining current projects that seek to contrast the atmospheres and chemical compositions of RRc stars with those of the RRab stars, and that employ a much larger RRab sample in a chemo-dynamical study of Galactic halo RR Lyr.

Sneden, Christopher; For, Bi-Qing; Preston, George W.



Synthesis and characterization of Co\\/ZnO nanocomposites: towards new perspectives offered by metal\\/piezoelectric composite materials  

Microsoft Academic Search

A new type of composite material, consisting of metallic cobalt nanoparticles dispersed within a piezoelectric ZnO matrix has been elaborated by a sol–gel process. Cobalt and zinc salt solutions with a cobalt to zinc atomic ratio equal to 0.1 have been spin-coated onto fused quartz substrates and films of 400 nm thickness have been obtained. An annealing of the as-deposited

N. Viart; M Richard-Plouet; D Muller; G Pourroy



Visualizing excipient composition and homogeneity of Compound Liquorice Tablets by near-infrared chemical imaging.  


This study demonstrated that near-infrared chemical imaging (NIR-CI) was a promising technology for visualizing the spatial distribution and homogeneity of Compound Liquorice Tablets. The starch distribution (indirectly, plant extraction) could be spatially determined using basic analysis of correlation between analytes (BACRA) method. The correlation coefficients between starch spectrum and spectrum of each sample were greater than 0.95. Depending on the accurate determination of starch distribution, a method to determine homogeneous distribution was proposed by histogram graph. The result demonstrated that starch distribution in sample 3 was relatively heterogeneous according to four statistical parameters. Furthermore, the agglomerates domain in each tablet was detected using score image layers of principal component analysis (PCA) method. Finally, a novel method named Standard Deviation of Macropixel Texture (SDMT) was introduced to detect agglomerates and heterogeneity based on binary image. Every binary image was divided into different sizes length of macropixel and the number of zero values in each macropixel was counted to calculate standard deviation. Additionally, a curve fitting graph was plotted on the relationship between standard deviation and the size length of macropixel. The result demonstrated the inter-tablet heterogeneity of both starch and total compounds distribution, simultaneously, the similarity of starch distribution and the inconsistency of total compounds distribution among intra-tablet were signified according to the value of slope and intercept parameters in the curve. PMID:22079891

Wu, Zhisheng; Tao, Ou; Cheng, Wei; Yu, Lu; Shi, Xinyuan; Qiao, Yanjiang



Single-component chemically amplified resist materials for electron-beam and x-ray lithography  

Microsoft Academic Search

Copolymers of 4-tert-butoxycarbonyloxystyrene (TBS) and sulfur dioxide (SO2) have been found to act as sensitive x-ray ((lambda) equals 14 angstrom) and moderately sensitive electron-beam, single component, chemically amplified, aqueous base soluble positive acting resists. The x-ray and electron-beam response of these materials was a function of copolymer composition, where an increase in the sulfur dioxide content enhanced the resist sensitivity.

Anthony E. Novembre; Woon W. Tai; Janet M. Kometani; James E. Hanson; Omkaram Nalamasu; Gary N. Taylor; Elsa Reichmanis; Larry F. Thompson



Compositional and physico-optical characterization of 0-5% Al-doped zinc oxide films prepared by chemical spray pyrolysis  

Microsoft Academic Search

Highly transparent polycrystalline Al-doped ZnO thin films were deposited in open atmosphere by chemical spray pyrolysis on fused silica and glass substrates at 623 K. The influence of Al doping, 0 to 5%, was studied. XPS results revealed a linear relationship between Al content in the precursor solutions and Al content in the films. XPS depth profiling showed that any

R. Romero; R. López-Ibáñez; E. A. Dalchiele; J. R. Ramos-Barrado; F. Martín; D. Leinen



Chemical Softening and Wear of Dental Composites  

Microsoft Academic Search

The purpose of this work was to determine the influence of chemical food-simulating liquids on the wear of various commercial dental composite restoratives. In many cases, pre-conditioning the restoratives in these liquids for one week produced swelling of the polymer matrix and considerable surface damage. The resulting degradation reduced the hardness and enhanced the wear as measured by a pin-and-disc

J. E. McKinney; W. Wu



Polyaniline–silver composites prepared by the oxidation of aniline with mixed oxidants, silver nitrate and ammonium peroxydisulfate: The control of silver content  

Microsoft Academic Search

Aniline was oxidized with mixtures of two oxidants, ammonium peroxydisulfate and silver nitrate, to give polyaniline–silver composites with variable content of silver in the composites. The presence of peroxydisulfate has a marked accelerating effect on the oxidation of aniline with silver nitrate. Oxidations in 1 M methanesulfonic acid produced composites in high yield. The molecular structure of the polyaniline was confirmed

Patrycja Bober; Jaroslav Stejskal; Miroslava Trchová; Jan Prokeš


Polarity controlled by the composition of inorganic recording materials in Al-Si binary system  

Microsoft Academic Search

A technique was introduced to control the polarity of discs. Inorganic materials of binary Al-Si were used as recording layers in our study. By adjusting the layer thickness of Al and Si individually, we found that over a certain thickness ratio of Al-Si double layers, the reflectivity shift measured by a static tester altered from high-to-low into low-to-high. By using

Ru-Lin Yeh; Hsun-Hao Chang; Bing-Mau Chen; Teng-Chien Yu



Laser-induced fluorescence: quantitative analysis of atherosclerotic plaque chemical content in human aorta  

NASA Astrophysics Data System (ADS)

We have been studying laser-induced fluorescence as a technique for identification of selected changes in the chemical composition of atherosclerotic plaque. Formulae for quantification of chemical changes have been developed based upon analysis of fluorescence emission spectra using multiple regression analysis and the principal of least squares. The intima of human aortic necropsy specimens was injected with chemical compounds present in atherosclerotic plaque. Spectra recorded after injection of selected chemical components found in plaque (collagen I, III, IV, elastin and cholesterol) at varying concentrations (0.01 - 1.0 mg) were compared with saline injection. A single fiber system was used for both fluorescence excitation (XeCl excimer laser, 308 nm, 1.5 - 2.0 mJ/ pulse, 5 Hz) and fluorescence emission detection. Average spectra for each chemical have been developed and the wavelengths of peak emission intensity identified. Curve fitting analysis as well as multiple regression analysis were used to develop formulae for assessment of chemical content. Distinctive identifying average curves were established for each chemical. Excellent correlations were identified for collagen I, III, and IV, elastin, and cholesterol (R2 equals 0.92 6- 0.997). Conclusions: (1) Fluorescence spectra of human aortas were significantly altered by collagen I, collagen III, elastin and cholesterol. (2) Fluorescence spectroscopic analysis may allow quantitative assessment of atherosclerotic plaque chemical content in situ.

Dai, Erbin; Wishart, David; Khoury, Samir; Kay, Cyril M.; Jugdutt, Bodh I.; Tulip, John; Lucas, Alexandra




Microsoft Academic Search

This paper presents the transformations which take place during the obtaining process of bimetallic materials. As a plating process was used the welding. The added material was a bronze with aluminum complex alloyed with iron, nickel. The based material was the steel. EDAX analyses and microstructures analyses were done in order to explain the metallurgical processes which take place during

Felicia Bratu


Chemical composition and nutritional evaluation of various foliages consumed by mithun ( Bos frontalis)  

Microsoft Academic Search

Mithun (Bos frontalis) is primarily reared in free-grazing systems and several tropical foliages are important feed resources for it throughout the year. Inadequate information is available on the nutritive value of most of these foliages. This study aimed to determine the nutrient composition and in situ degradability of dry matter (DM) and crude protein (CP) of the major foliages consumed

B. Prakash; A. Dhali; S. S. Rathore; K. C. Das; I. Walling; K. Vupru; A. Mech; K. K. Baruah; C. Rajkhowa



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

SciTech Connect

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.

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



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

Microsoft Academic Search

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,

Dennis Patrick Roach; Randy L. Duvall



Hierarchically porous nickel hydroxide\\/mesoporous carbon composite materials for electrochemical capacitors  

Microsoft Academic Search

Hierarchically porous composite materials consisting of nanoflake-like nickel hydroxide and mesoporous carbon are synthesized by a facile chemical precipitation method. The effects of microstructure and morphology of the carbon support on the electrochemical properties of the composite are also investigated. Structural characterizations have revealed that nanometer-sized nickel hydroxide nanoflakes can grow on the surface of mesoporous carbon supports. The mesoporous

Jing Zhang; Ling-Bin Kong; Jian-Jun Cai; Heng Li; Yong-Chun Luo; Long Kang



Abrasive rolling effects on material removal and surface finish in chemical mechanical polishing analyzed by molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

In an abrasive chemical mechanical polishing (CMP) process, materials were considered to be removed by abrasive sliding and rolling. Abrasive sliding has been investigated by many molecular dynamics (MD) studies; while abrasive rolling was usually considered to be negligible and therefore was rarely investigated. In this paper, an MD simulation was used to study the effects of abrasive rolling on material removal and surface finish in the CMP process. As the silica particle rolled across the silicon substrate, some atoms of the substrate were dragged out from their original positions and adhered to the silica particle, leaving some atomic vacancies on the substrate surface. Meanwhile, a high quality surface could be obtained. During the abrasive rolling process, the influencing factors of material removal, e.g., external down force and driving force, were also discussed. Finally, MD simulations were carried out to examine the effects of abrasive sliding on material removal under the same external down force as abrasive rolling. The results showed that the ability of abrasive rolling to remove material on the atomic scale was not notably inferior to that of abrasive sliding. Therefore, it can be proposed that both abrasive sliding and rolling play important roles in material removal in the abrasive CMP of the silicon substrate.

Si, Lina; Guo, Dan; Luo, Jianbin; Lu, Xinchun; Xie, Guoxin



Surface morphology and ferroelectric properties of compositional gradient PZT thin films prepared by chemical solution deposition process  

NASA Astrophysics Data System (ADS)

A series of PbTiO3/PbZrxTil-xO3 (PT/PZT) and PbZrO3/PbZrxTil-xO3 (PZ/PZT) compositional gradient thin films are obtained by chemical solution decomposition (CSD) method. The influences of buffer layers on surface morphology are investigated. Thin films with buffer layer are able to maintain the perovskite structure with (1 1 1)-preferred orientation. The surface microstructure and ferroelectric properties of the PZT thin films differs significantly depending on the use of PT or PZ buffer layers. When the PT buffer layer has five layers, the root mean square roughness (RMS) [17.7 nm] and remnant polarization (Pr) [35.83 ?C/cm2] are maximized. On the other hand, when PZ buffer layer has one layer, the RMS [3.67 nm] and Pr [26.08 ?C/cm2] are also maximized. The down-graded (Zr composition varying from 0.6 at the bottom surface to 0.4 at top surface) thin films exhibit larger surface roughness and better ferroelectric property than up-graded (Zr composition varying from 0.4 at the bottom surface to 0.6 at top surface) thin films. Therefore, different buffer layer determines different surface morphology. It is concluded that the ferroelectric property of the gradient thin films not only depends on its composition structure, but can also be controlled by the surface morphology. The results indicate that the PZT films with better ferroelectric property should have larger surface roughness.

He, Gang; Zhang, Yao; Peng, Chao; Li, Xiaomeng



Identification of lead chemical form in mine waste materials by X-ray absorption spectroscopy  

SciTech Connect

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.

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)



Recovery of rare metals from scrap of rare earth intermetallic material by chemical vapour transport  

Microsoft Academic Search

A dry process for recovery of rare metals from sludges of Sm2Co17, Nd2Fe14B and LaNi5 intermetallic compounds was investigated using chemical vapour transport along a given temperature gradient. Chlorine and aluminium chloride were used as a chlorinating agent and a transporting agent respectively, and the rare metal chlorides were chemically transported as vapour complexes, e.g. RAlnCl3+3n (R = rare earth),

Kuniaki Murase; Ken-ichi Machida; Gin-ya Adachi



Properties of Five Toughened Matrix Composite Materials.  

National Technical Information Service (NTIS)

The use of toughened matrix composite materials offers an attractive solution to the problem of poor damage tolerance associated with advanced composite materials. In this study, the unidirectional laminate strengths and moduli, notched (open-hole) and un...

R. J. Cano M. B. Dow



Composite, Ordered Material Having Sharp Surface Features.  

National Technical Information Service (NTIS)

A composite material having sharp surface features includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite material having an etched surface wh...

B. R. D'Urso J. T. Simpson



Exposure Assessment of Chemicals from Packaging Materials  

NASA Astrophysics Data System (ADS)

A variety of chemicals may enter our food supply, by means of intentional or unintentional addition, at different stages of the food chain. These chemicals include food additives, pesticide residues, environmental contaminants, mycotox-ins, flavoring substances, and micronutrients. Packaging systems and other food-contact materials are also a source of chemicals contaminating food products and beverages. Monitoring exposure to these chemicals has become an integral part of ensuring the safety of the food supply. Within the context of the risk analysis approach and more specifically as an integral part of risk assessment procedures, the exercise known as exposure assessment is crucial in providing data to allow sound judgments concerning risks to human health. The exercise of obtaining this data is part of the process of revealing sources of contamination and assessing the effectiveness of strategies for minimizing the risk from chemical contamination in the food supply (Lambe, 2002).

Poças, Maria De Fátima; Hogg, Timothy


Improved Process for the Preparation of Fiber-Reinforced Ceramic Composites by Chemical Vapor Deposition.  

National Technical Information Service (NTIS)

A specially designed apparatus provides a steep thermal gradient across the thickness of fibrous preform. A flow of gaseous ceramic matrix material is directed into the fibrous preform at the cold surface. The deposition of the matrix occurs progressively...

W. J. Lackey A. J. Caputo



Adiabatic shear failure of high reinforcement content aluminum matrix composites  

Microsoft Academic Search

Dynamic failure behaviors of high reinforcement content TiB2\\/Al composites were experimentally investigated using split Hopkinson pressure bar (SHPB). The TiB2\\/Al composites showed high flow stresses and good plastic deformation ability at high strain rates. Adiabatic temperature\\u000a rise decreased the flow stresses of TiB2\\/Al composites, which was verified by the prediction of Johnson–Cook model. While the predictions by Cowper–Symonds model\\u000a exhibited

G. H. Wu; D. Z. Zhu; G. Q. Chen; L. T. Jiang; Q. Zhang



Chemical composition of lipids present in cat and dog oocyte by matrix-assisted desorption ionization mass spectrometry (MALDI- MS).  


The aim of the present study was to investigate the level of information on the chemical structures and relative abundances of lipids present in cat and dog oocytes by matrix-assisted laser desorption mass spectrometry (MALDI-MS). The MALDI-MS approach requires a simple analysis workflow (no lipid extraction) and few samples (two or three oocytes per analysis in this work) providing concomitant profiles of both intact phospholipids such as sphingomyelins (SM) and phosphatidylcholines (PC) as well as triacylglycerols (TAG). The lipids were detected in oocytes by MALDI using dihydroxybenzoic acid (DHB) as the matrix. The most abundant lipid present in the MS profiles of bitch and queen oocytes was a PC containing 34 carbons and one unsaturation [PC (34:1)]. Oocytes of these two species are characterized by differences in PC and TAG profiles detected qualitatively as well as by means of principal component analysis (PCA). Cat oocytes were mainly discriminated by more intense C52 and C54 TAG species and a higher number of unsaturations, indicating predominantly linoleic and oleic fatty acyl residues. Comparison of the lipid profile of bitch and queen oocytes with that of bovine oocytes revealed some similarities and also some species specificity: TAG species present in bovine oocytes were also present in bitches and queens; however, a more pronounced contribution of palmitic, stearic and oleic fatty acid residues was noticed in the lipid profile of bovine oocytes. MALDI-MS provides novel information on chemical lipid composition in canine and feline oocytes, offering a suitable tool to concomitantly monitor, in a nearly direct and simple fashion the composition of phospholipids and TAG. This detailed information is highly needed to the development of improved protocols for in vitro culture and cryopreservation of cat and dog oocytes. PMID:23279478

Apparicio, M; Ferreira, C R; Tata, A; Santos, V G; Alves, A E; Mostachio, G Q; Pires-Butler, E A; Motheo, T F; Padilha, L C; Pilau, E J; Gozzo, F C; Eberlin, M N; Lo Turco, E G; Luvoni, G C; Vicente, W R R



Numerical simulations of crack propagation driven by stress-assisted corrosion in brittle solids and composite materials  

Microsoft Academic Search

When many glasses and ceramic materials are subject to static loading as well as a chemically reactive environment, they often experience delayed failure due most likely to stress-assisted chemical reactions at the cracks: pre-existing surface flaws grow to a critical length, at which point unstable rapid crack propagation ensues, leading to catastrophic failure. For a given material and ambient environment,

Zhibo Tang



Growth and chemical composition of dry beans as affected by soil salinity and N fertilization  

Microsoft Academic Search

Summary The effects of three levels of N (0, 50 and 100 ppm) and four salinity regimes (0.5, 1.5, 2.5 and 3.5 mmhos\\/cm) on the growth and mineral composition of dry beans (Phaseolus vulgaris L.) were investigated in a greenhouse experiment. Bean plants treated with N produced more dry weight and contained higher N than the untreated check. Growth and

A. M. Sameni; M. Maftoun; A. Bassiri; A. R. Sepaskhah



Seasonal variation in botanical and chemical composition of plants selected by one-humped camel (Camelus dromedarius).  


The present study has been conducted in order to investigate the seasonal variation in the botanical and chemical composition of plant parts consumed by camels (Camelus dromedarius). The study has been conducted on 210 indigenous Arabian camel of different age (1-18 years) and sex and kept under natural range in southern Darfur, Sudan. The findings of the present study indicate that camels are selective browser rather than grazer. Furthermore, they are selective feeder to the parts of pasture plants they consume. The percentages of Crude Protein (CP), Crude Fibre (CF) and Nitrogen Free Extract (NFE) of pasture plants selected by camels were significantly higher, while ash percentage was significantly lower during the dry season. PMID:19069892

Amin, Alia S A; Abdoun, Khalid A; Abdelatif, Abdalla M



Influence of sundrying on the chemical composition, aflatoxin content and fungal counts of two pepper varieties--Capsicum annum and Capsicum frutescens.  


Samples of sundried, matured red pepper, Capsicum annum with a moisture content (MC) of 12.7-26.8 percent had on dry weight basis, vitamin C, 5.0-6.4 mg/100 g; crude protein, 0.8-1.2 percent; total soluble solids, 3.3-4.1 percent, and fungal counts of log 4.4-4.5/g. Ordinary matured red C. annum had MC, 75.7-78.2 percent vitamin C, 36.1-38.5 mg/100 g; crude protein, 2.4-2.8 percent; total soluble solids, 9.3-9.9 percent and fungal count of log 3.32-3.39/g. Sundried matured red C. frutescens had corresponding values of 9.4-18.7 percent; 5.8-6.3 mg/100 g; 0.8-1.1 percent; 0.9-2.6 percent and log 3.2-3.4/g. No aflatoxins were detected in sundried, matured red C. frutescens, but aflatoxin B1 values obtained from C. annum varied from non-detectable to 2.2 micrograms/kg. Dominant fungi isolated from C. annum and C. frutescens were Rhizopus oryzaze, Aspergillus niger, A. flavus, Geotrichum candidum and Saccharomyces spp. PMID:8811723

Adegoke, G O; Allamu, A E; Akingbala, J O; Akanni, A O



A Dynamic Method Determining Equilibrium Moisture Content of Porous Materials  

Microsoft Academic Search

Equilibrium moisture content is an important moisture characteristics of porous materials, but its determination has required considerable time and care and the judgement of equilibrium may eventually be arbitrary. Dynamic method that can predict the equilibrium moisture content by curve-fitting to sorption kinetics experiments was proposed in the absence of accuracy consideration. We have examined the kinetic equations and measurement

Shinsaku Tada; Kazumasa Watanabe


Effect of soil sodicity on the growth, yield and chemical composition of groundnut ( Arachis hypogaea Linn.)  

Microsoft Academic Search

Summary A replicated field experiment was conducted to study the effect of exchangeable sodium percentage (ESP) on the yield, chemical composition, protein and oil content and uptake of nutrients by groundnut (Arachis hypogaea Linn.) variety M-13. ESP over 15 delayed germination and emergence of flowers. There was continuous decrease in dry matter yield at 30 and 60 days of growth,

S. B. Singh; I. P. Abrol



Chemical microsensors based on polymer fiber composites  

NASA Astrophysics Data System (ADS)

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.

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



Interlaminar fracture and damage of composite materials  

Microsoft Academic Search

Interlaminar fracture behavior of composite materials under static and cyclic loadings was studied. The fracture energy is evaluated by compliance, beam and area methods. The comparison results show that the initial fracture energy could be evaluated either by beam or area method while the crack growth resistance could be calculated by compliance method. Increases in the critical load and fracture



Visualizing excipient composition and homogeneity of Compound Liquorice Tablets by near-infrared chemical imaging  

Microsoft Academic Search

This study demonstrated that near-infrared spectroscopy chemical imaging (NIR-CI) was a promising technology for visualizing the spatial distribution and homogeneity of Compound Liquorice Tablets. The starch distribution (indirectly, plant extraction) could be spatially determined using basic analysis of correlation between analytes (BACRA) method. The correlation coefficients between starch spectrum and spectrum of each sample were greater than 0.95. Depending on

Zhisheng Wu; Ou Tao; Wei Cheng; Lu Yu; Xinyuan Shi; Yanjiang Qiao



PubMed Central

The search of aesthetic dental material is on. Composites are a material of choice in this category. Composite have developed over past few years and increased use of material is in demand. This article gives us a brief knowledge of existing and newer composites.




Polarity controlled by the composition of inorganic recording materials in Al-Si binary system  

NASA Astrophysics Data System (ADS)

A technique was introduced to control the polarity of discs. Inorganic materials of binary Al-Si were used as recording layers in our study. By adjusting the layer thickness of Al and Si individually, we found that over a certain thickness ratio of Al-Si double layers, the reflectivity shift measured by a static tester altered from high-to-low into low-to-high. By using this technique, the feasibility for making both types of discs has been proved according to good testing results from dynamic tester.

Yeh, Ru-Lin; Chang, Hsun-Hao; Chen, Bing-Mau; Yu, Teng-Chien



Chlorhexidine-releasing methacrylate dental composite materials.  


Light curable antibacterial, dental composite restoration materials, consisting of 80 wt% of a strontium fluoroaluminosilicate glass dispersed in methacrylate monomers have been produced. The monomers contained 40-100 wt% of a 10 wt% chlorhexidine diacetate (CHXA) in hydroxyethylmethacrylate (HEMA) solution and 60-0 wt% of a 50/50 mix of urethane dimethacrylate (UDMA) and triethyleneglycol dimethacrylate (TEGDMA). On raising HEMA content, light cure polymerisation rates decreased. Conversely, water sorption induced swelling and rates of diffusion controlled CHXA release from the set materials increased. Experimental composites with 50 and 90 wt% of the CHXA in HEMA solution in the monomer were shown, within a constant depth film fermentor (CDFF), to have slower rates of biofilm growth on their surfaces between 1 and 7 days than the commercial dental composite Z250 or fluoride-releasing dental cements, Fuji II LC and Fuji IX. When an excavated bovine dentine cylinder re-filled with Z250 was placed for 10 weeks in the CDFF, both bacteria and polymers from the artificial saliva penetrated between the material and dentine. With the 50 wt% experimental HEMA/CHXA formulation, this bacterial microleakage was substantially reduced. Polymer leakage, however, still occurred. Both polymer and bacterial microleakage were prevented with a 90 wt% HEMA/CHXA restoration in the bovine dentine due to swelling compensation for polymerisation shrinkage in combination with antibacterial release. PMID:15955557

Leung, Danny; Spratt, David A; Pratten, Jonathan; Gulabivala, Kishor; Mordan, Nicola J; Young, Anne M



Manufacturing of hard magnetic composite materials Nd-Fe-B  

Microsoft Academic Search

Purpose: This paper presents the material and technological solution which makes it possible obtaining of hard magnetic composite materials: nanocrystalline material - polymer. Design\\/methodology\\/approach: For fabrication of composite materials the Nd-Fe-B powder obtained by melt quenching technique was used and for matrix: epoxy resin (EP) or high density polyethylene (HDPE) (2.5 % wt.). Composite materials were compacted by the one-sided

M. Drak; B. Zi?bowicz; L. A. Dobrza?ski


Modification of cast aluminum-matrix composite materials by refractory nanoparticles  

NASA Astrophysics Data System (ADS)

The effect of SiO2 and Al2O3 oxide ceramic nanoparticles on the solidification of model samples based on a commercial D16 alloy is studied. The composite samples are fabricated by reaction casting when titanium, nickel, and ceramic powders are mixed with an aluminum melt. The grain size in a matrix, the size and shape of Al3Ti intermetallic inclusions, and the interphase distances in eutectics are determined with optical and scanning electron microscopes. A certain modifying effect of oxide ceramic nanoparticles on the structure of model CMs during their in situ formation is detected, and the inoculation effect of SiO2 added to a melt on the reaction products is most pronounced.

Chernyshova, T. A.; Kobeleva, L. I.; Kalashnikov, I. E.; Bolotova, L. K.



Chemical Corrosion Effect on Wood and Wood–Plastic Composites  

Microsoft Academic Search

Effect of chemical corrosion on the tensile strengths of five types of Bangladeshi timbers (kadom, simul, koroi, mango, and debdaro) and their composites has been evaluated. Wood–plastic composites (WPC) formed by the gamma-radiation induction polymerization of butylmethacrylate (BMA) with those timbers show better resistance to chemical corrosion attack than the parent timbers. Enhanced mechanical properties such as tensile strength of

M. A. Khan; K. M. Idriss Ali; M. U. Ahmed



Chemical composition of teff (Eragrostis tef) compared with that of wheat, barley and grain sorghum  

Microsoft Academic Search

The chemical composition of teff, analyzed from uncontaminated seeds, revealed the superiority of the species in mineral nutritive\\u000a value. Teff’s exceedingly high iron and calcium content was confirmed. The high iron content of teff reported by the Ethiopia\\u000a Nutrition Survey must have been due to certain inherent factors of the species, not only a result of contamination. The magnitude\\u000a of

Melak H. Mengesha



Preparation, chemical composition and storage studies of quamachil ( Pithecellobium dulce L.) aril powder  

Microsoft Academic Search

Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging\\u000a systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively.\\u000a The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril

Galla Narsing Rao; Allani Nagender; Akula Satyanarayana; Dubasi Govardhana Rao



Chemical composition and antioxidant activity of yerba-mate (Ilex paraguariensis A.St.-Hil., Aquifoliaceae) extract as obtained by spray drying.  


Yerba-mate or mate? (Ilex paraguariensis A.St.-Hil., Aquifoliaceae) leaves are typically used for their stimulant, antioxidant, antimicrobial, and diuretic activity, presenting as principal components polyphenolic compounds. In this study, the objective was to develop a yerba-mate dry extract by using spray drying technology and to evaluate the dry extract antioxidant activity and chemical composition. The results obtained by means of the DPPH assay show that the extract presents an IC(50) of 2.52 mg/mL. The yerba-mate spray-dried extract presents high catalase-like activity, suggesting that it is a strong free-radical scavenger. The antioxidant activity as expressed as catalase-like activity was related to total polyphenol content. In addition, the results show that the spray-dried extract presents high polyphenol content, namely, high concentrations of caffeic acid (1.54 mg/g), 5-caffeoylquinic acid (91.40 mg/g), rutin (5.38 mg/g), and total phenolics (178.32 mg/g), which justifies its high antioxidant activity. PMID:21510640

Berté, Kleber A S; Beux, Marcia R; Spada, Patricia K W D S; Salvador, Mirian; Hoffmann-Ribani, Rosemary



Study of chemical activation process of a lignocellulosic material with KOH by XPS and XRD  

Microsoft Academic Search

Chemical activation of carbons is currently a very common method for obtaining activated carbons with very high surface areas. KOH is one of the most effective agents employed for this purpose. However, the reaction mechanism of this kind of activation it is not yet completely elucidated, although some models have been proposed. In this paper, an activated charcoal was obtained

J. D??az-Terán; D. M. Nevskaia; J. L. G. Fierro; A. J. López-Peinado; A. Jerez



Improving student achievement in the topic of chemical energy by implementing new learning materials and strategies  

Microsoft Academic Search

In order to reduce difficulties and misconceptions in the topic of chemical energy, a new learning package was developed and implemented in Israeli high?school classes. The implementation was based on a variety of learning activities which optimized students’ involvement in the learning process. Two experimental groups, which differed in the sequence of these learning activities, and a control group participated

Ita Cohen; Ruth Ben-Zvi



Molybdate\\/Al(III) composite films on steel and zinc-plated steel by chemical conversion  

Microsoft Academic Search

A molybdate(VI)–Al(III) chemical conversion process was developed as an alternative to the chromate processes. Steel and zinc-plated steel specimens were treated in the solutions of 0.16 moll?1 ammonium alum (AlNH4(SO4)2·12H2O) with small amounts of ammonium molybdate(VI) (0.002–0.016 moll?1 (NH4)6Mo7O24·4H2O) at 60 °C for 10–30 min in an ultrasonic rinsing apparatus. The formed films were composed of oxyhydroxides containing Mo(V,VI), Al(III),

H. Konno; K. Narumi; H. Habazaki



Agronomic Characteristics and Chemical Composition of Newly Developed Day-Neutral Strawberry Lines by Agriculture and Agri-Food Canada  

Microsoft Academic Search

The agronomic characteristics and chemical composition of seven advanced day-neutral strawberry lines and a commercial cultivar ‘Seascape’ were evaluated for their horticulture and quality attributes. The results showed that the advanced strawberry lines had the best horticultural characteristics, such as more resistance to diseases, less weight and juice losses and better fruit glossiness during storage, compared to ‘Seascape’. Among the

Qinglian Wang; Emmanuel Tury; Djamila Rekika; Marie Thérèse Charles; Rong Tsao; Yu-Jin Hao; Claudine Dubé; Shahrokh Khanizadeh



The tooth attachment mechanism defined by structure, chemical composition and mechanical properties of collagen fibers in the periodontium  

Microsoft Academic Search

In this study, a comparison between structure, chemical composition and mechanical properties of collagen fibers at three regions within a human periodontium, has enabled us to define a novel tooth attachment mechanism. The three regions include, (1) the enthesis region: insertion site of periodontal ligament (PDL) fibers (collagen fibers) into cementum at the root surface, (2) bulk cementum, and (3)

Sunita P. Ho; Sally J. Marshall; Mark I. Ryder; Grayson W. Marshall



Chemical Compositions and Functional Properties of Protein Isolated from By-Product of Triangle Shell Pearl Mussel Hyriopsis cumingii  

Microsoft Academic Search

Hyriopsis cumingii is a freshwater mussel widely cultured in China to produce cultured pearls. However, after the pearls are harvested, the mussel is discarded. To make effective utilization of pearl production wastes, proteins were recovered from the pearl mussel meat using pH shift technology. The protein recovery conditions, chemical compositions, and functional properties of the recovered protein were investigated. Results

Chengchu Liu; Haiyan Zhou; Yi-Cheng Su; Yingsen Li; Jiale Li



Composition and content of glucosinolates in developing Arabidopsis thaliana  

Microsoft Academic Search

The glucosinolate composition and content in various tissues of Arabidopsis thaliana (L.) Heynh. ecotype Columbia during development from seeds to bolting plants were determined in detail by high-performance liquid chromatography. Comparison of the glucosinolate profiles of leaves, roots and stems from mature plants with those of green siliques and mature seeds indicated that a majority of the seed glucosinolates were

Bent Larsen Petersen; Sixue Chen; Carsten Hørslev Hansen; Carl Erik Olsen; Barbara Ann Halkier



Composite material heat pipe radiator  

SciTech Connect

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. {copyright} {ital 1996 American Institute of Physics.}

Gernert, N.J.; Sarraf, D.B. [Thermacore, Inc., 780 Eden Road, Lancaster, Pennsylvania 17601 (United States); Guenther, R.J. [Battelle, Pacific Northwest Laboratories, Richland, Washington 99352 (United States); Hurlbert/, K.M. [NASA Johnson Space Center, 2101 NASA Road, 1 Houston, Texas 77058-3696 (United States); EC3



Chemical composition and 13C NMR spectroscopic characterisation of ulvans from Ulva (Ulvales, Chlorophyta)  

Microsoft Academic Search

The chemical composition and structures of several ulvan extracts isolated from various Ulva species were studied. They were\\u000a all composed mainly of rhamnose, glucuronic acid, xylose, glucose and sulphate with smaller amounts of iduronic acid and traces\\u000a of galactose. Proteins were also present, most likely as contaminants. Precise quantification of the uronic acid content by\\u000a chemical-enzymatic hydrolysis coupled to HPAEC-PAD

Marc Lahaye; Enrique Alvarez-Cabal Cimadevilla; Ralph Kuhlenkamp; Bernard Quemener; Vincent Lognoné; Patrick Dion



Detection of adulteration of pumpkin seed oil by analysis of content and composition of specific ?7-phytosterols  

Microsoft Academic Search

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

Alexandra Mandl; Gregor Reich; W. Lindner



Optimizing Material Use in Blade Design by Improving Failure Prediction Methodology and Introducing Damage Tolerant Concepts in FRP Composites  

Microsoft Academic Search

Preliminary results are presented in this work, concerning the validation of a reliable FEM tool under development, featuring damage tolerant concepts, to enhance design capabilities and optimize material use in large composite structures. User defined material constitutive equations concerning anisotropic non- linearity and material stiffness degradation as a result of damage accumulation, are implemented to model inherent damage tolerance of

A. E. Antoniou; T. P. Philippidis


Carbon Nano Tube Composites with Chemically Functionalized Plant Oils  

Microsoft Academic Search

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

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



Sweet Basil ( Ocimum basilicum ) Extracts Obtained by Supercritical Fluid Extraction (SFE): Global Yields, Chemical Composition, Antioxidant Activity, and Estimation of the Cost of Manufacturing  

Microsoft Academic Search

In this work, supercritical technology was used to obtain extracts from Ocimum basilicum (sweet basil) with CO2 and the cosolvent H2O at 1, 10, and 20% (w\\/w). The raw material was obtained from hydroponic cultivation. The extract’s global yield isotherms, chemical compositions,\\u000a antioxidant activity, and cost of manufacturing were determined. The extraction assays were done for pressures of 10 to

Patrícia F. Leal; Nilson B. Maia; Quirino A. C. Carmello; Rodrigo R. Catharino; Marcos N. Eberlin; M. Angela A. Meireles



Silica\\/poly( N, N?-methylenebisacrylamide) composite materials by encapsulation based on a hydrogen-bonding interaction  

Microsoft Academic Search

Monodisperse silica\\/poly(N,N?-methylenebisacrylamide) core–shell composite materials with silica as core and poly(N,N?-methylenebisacrylamide) (PMBAAm) as shell were prepared by a two-stage reaction, in which the silica core with diameter of 500nm was synthesized in the first stage according to Stöber method. The PMBAAm shell was then encapsulated over the silica core by distillation–precipitation polymerization of N,N?-methylenebisacrylamide (MBAAm) in neat acetonitrile with 2,2?-azobisisobutyronitrile (AIBN)

Guangyu Liu; Xinlin Yang; Yongmei Wang



Chemical surface composition of the polyethylene implanted by Ag + ions studied by phase imaging atomic force microscopy  

Microsoft Academic Search

High density polyethylene (HDPE) has been modified by Ag+ ion implantation with the energy of 60keV. The total amount of implanted silver ions was 1, 5 and 12×1015 ions\\/cm2. The surface topography was observed by atomic force microscopy (AFM), while the surface composition changes were detected using phase imaging AFM. Surface topography changes were studied in detail using 3D surface

S. Strbac; M. Nenadovic; Lj. Rajakovic; Z. Rakocevic



Process for Fixing Arsenic Bearing Materials and Arsenic Containing Composites Formed by Said Process.  

National Technical Information Service (NTIS)

A process is described for fixing arsenic bearing material which comprises the steps of: adding the arsenic bearing material to a molten slag; mixing the arsenic bearing material into the molten slag to form a slag mixture; and permitting the slag mixture...

A. Mehta L. Twidwell



Thermal Expansion of High Filler Content Cellulose-Plastic Composites  

Microsoft Academic Search

The effects of resin content (10–30%), cellulose fiber length (120 and 300 micrometer), and molding conditions (press, injection, and extrusion molding) on the thermal expansion of high filler content cellulose\\/polypropylene composites were evaluated. Other physical properties such as densities, bending strengths, and water absorption of composites were also determined. The results indicated that thermal expansion of composites is dependent on

Hirokazu Ito; Hidehiro Hattori; Tadashi Okamoto; Masahiro Takatani



Urban stormwater runoff drives denitrifying community composition through changes in sediment texture and carbon content.  


The export of nitrogen from urban catchments is a global problem, and denitrifying bacteria in stream ecosystems are critical for reducing in-stream N. However, the environmental factors that control the composition of denitrifying communities in streams are not well understood. We determined whether denitrifying community composition in sediments of nine streams on the eastern fringe of Melbourne, Australia was correlated with two measures of catchment urban impact: effective imperviousness (EI, the proportion of a catchment covered by impervious surfaces with direct connection to streams) or septic tank density (which affects stream water chemistry, particularly stream N concentrations). Denitrifying community structure was examined by comparing terminal restriction fragment length polymorphisms of nosZ genes in the sediments, as the nosZ gene codes for nitrous oxide reductase, the last step in the denitrification pathway. We also determined the chemical and physical characteristics of the streams that were best correlated with denitrifying community composition. EI was strongly correlated with community composition and sediment physical and chemical properties, while septic tank density was not. Sites with high EI were sandier, with less fine sediment and lower organic carbon content, higher sediment cations (calcium, sodium and magnesium) and water filterable reactive phosphorus concentrations. These were also the best small-scale environmental variables that explained denitrifying community composition. Among our study streams, which differed in the degree of urban stormwater impact, sediment grain size and carbon content are the most likely drivers of change in community composition. Denitrifying community composition is another in a long list of ecological indicators that suggest the profound degradation of streams is caused by urban stormwater runoff. While the relationships between denitrifying community composition and denitrification rates are yet to be unequivocally established, landscape-scale indices of environmental impact such as EI may prove to be useful indicators of change in microbial communities. PMID:21384215

Perryman, Shane E; Rees, Gavin N; Walsh, Christopher J; Grace, Michael R



Natural frequency behavior of damaged composite materials  

NASA Astrophysics Data System (ADS)

Attention is given to characterizing the effect of material system, geometry, and stacking sequence on the vibration response of damaged plates of fiber-reinforced composite. Plate layups are fashioned from various composite materials and subjected to four damage cycles, and a signal analyzer is employed to study the frequency response function (FRF) of the materials. The materials employed include the AS4/3501-6, IM7/E7T1-2, and IM7/977-2 families, and numerical analyses are used for comparison. Frequencies are obtained from the experimentally established FRFs, and natural frequencies tend to decrease in the presence of extensive localized damage. The fiber is argued to dominate the response of the plate, and the experimental data are confirmed in some cases by the results of finite-element calculations.

Duggan, M. B.; Ochoa, O. O.



Candida albicans adhesion to composite resin materials.  


The adhesion of Candida albicans to dental restorative materials in the human oral cavity may promote the occurrence of oral candidosis. This study aimed to compare the susceptibility of 14 commonly used composite resin materials (two compomers, one ormocer, one novel silorane, and ten conventional hybrid composites) to adhere Candida albicans. Differences in the amount of adhering fungi should be related to surface roughness, hydrophobicity, and the type of matrix. Cylindrical specimens of each material were made according to the manufacturers' instructions. Surface roughness R (a) was assessed by perthometer measurements and the degree of hydrophobicity by computerized contact angle analysis. Specimens were incubated with a reference strain of C. albicans (DMSZ 1386), and adhering fungi were quantified by using a bioluminometric assay in combination with an automated plate reader. Statistical differences were analyzed by the Kruskal-Wallis test and Mann-Whitney U test. Spearman's rank correlation coefficients were calculated to assess correlations. Median R (a) of the tested composite resin materials ranged between 0.04 and 0.23 microm, median contact angles between 69.2 degrees and 86.9 degrees . The two compomers and the ormocer showed lower luminescence intensities indicating less adhesion of fungi than all tested conventional hybrid composites. No conclusive correlation was found between surface roughness, hydrophobicity, and the amount of adhering C. albicans. PMID:18810508

Bürgers, Ralf; Schneider-Brachert, Wulf; Rosentritt, Martin; Handel, Gerhard; Hahnel, Sebastian



Surface Chemical Composition of Size-fractionated Urban Walkway Aerosols Determined by XPS and ToF-SIMS  

NASA Astrophysics Data System (ADS)

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

Wenjuan, Cheng; Lu-Tao, Weng; Yongjie, Li; Arthur, Lau; Chak, Chan; Chi-Ming, Chan



The Chemical Composition of Maple Syrup  

ERIC Educational Resources Information Center

Maple syrup is one of several high-sugar liquids that humans consume. However, maple syrup is more than just a concentrated sugar solution. Here, we review the chemical composition of maple syrup. (Contains 4 tables and 1 figure.)

Ball, David W.



The Chemical Composition of Maple Syrup  

ERIC Educational Resources Information Center

|Maple syrup is one of several high-sugar liquids that humans consume. However, maple syrup is more than just a concentrated sugar solution. Here, we review the chemical composition of maple syrup. (Contains 4 tables and 1 figure.)|

Ball, David W.



Pyrolysis of municipal plastic wastes II: Influence of raw material composition under catalytic conditions  

SciTech Connect

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.

Lopez, A., E-mail: [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)



Variation of chemical composition in Australasian tektites from different localities in Vietnam  

NASA Astrophysics Data System (ADS)

One hundred and thirteen Australasian tektites from Vietnam (Hanoi, Vinh, Dalat, and Saigon areas) were analyzed for their major and trace element contents. The tektites are either of splash form or Muong Nong-type. The splash-form tektites have SiO2 contents ranging from 69.7 to 76.8 wt%, whereas Muong Nong-type tektites, which are considerably larger than splash-form tektites and have a blocky and chunky appearance, have slightly higher silica contents in the range of 74-81 wt%. Major-element relationships, such as FeO versus major oxides, Na2O versus K2O, and oxide ratio plots, were used to distinguish the different groups of the tektites. In addition, correlation coefficients have been calculated for each tektite group of this study. Many chemical similarities are noted between Hanoi and Vinh tektites from the north of Vietnam, except that the Hanoi tektites contain higher contents of CaO than Vinh; the higher content of CaO might be due to some carbonate parent material. Both Dalat and Saigon tektites have nearly similar composition, whereas the bulk chemistries of the tektites from Hanoi and Vinh appear different from those of Saigon and Dalat. There are differences, especially in the lower CaO and Na2O and higher MgO, FeO, for the tektites of Dalat and Saigon in comparison to that of Hanoi tektites. Furthermore, the Dalat and Saigon tektites show enrichments by factors of 3 and 2 for the Ni and Cr contents, respectively, compared to those of Hanoi and Vinh. The difference in chemistry between the North Vietnam tektites (Hanoi, Vinh) to that of South Vietnam tektites (Saigon, Dalat) of this study indicate that the parent material was heterogeneous and possibly mixing between different source rocks took place. Muong Nong-type tektites are enriched in the volatile elements such as Br, Zn, As, and Sb compared to the average splash-form tektites of this study. The chemical compositions of the average splash-form and Muong Nong-type tektites of this study closely resemble published data for average splash-form and Muong Nong-type indochinites, indicating that they have the same source. The trace element ratios Ba/Rb (2.7), Th/U (5.2), Th/Sc (1.3), Th/Sm (2.2), and the rare earth element (REE) abundances of this study show close similarities to those of average upper continental crust.

Amare, Kassa; Koeberl, Christian



Slow crack propagation in composite restorative materials.  


The double-torsion test technique was used to study slow crack propagation in a set of dental composite resins including two glass-filled and two microfilled materials. The microstructure within each pair was the same but one of the resins was selfcured and the other photocured. The fracture behavior was dependent on the filler concentration and the presence of absorbed water. Wet materials fractured by slow crack growth in the range of crack velocity studied (10(-7) to 10(-3) m/s), and the microfilled composites, which contain a lower concentration of inorganic filler, had lower stress intensity factors (K1c) than the glass-filled composites tested. Dry specimens of the microfilled materials and the selfcured, glass-filled composite also showed unstable, stick-slip fracture behavior indicative of a crack blunting mechanism which leads to an elevation of the stress intensity factor for crack initiation over K1c for stable crack growth. The plasticizing effect of water increased the viscoelastic response of the materials measured by the slope of curves of slow crack growth. Analysis of fracture surfaces showed that cracks propagated at low velocities (10(-7) to 10(-5) m/s) by the apparent failure of the filler/matrix interfacial bond, and absorbed water affected the strength or fracture resistance of the interface. At high crack velocities the properties of the composite depend on the properties of the polymeric matrix, the filler, and the filler volume fraction, but at low velocities the interface is the controlling factor in the durability of these composites exposed to an aqueous environment. PMID:3584167

Montes-G, G M; Draughn, R A



Colorimetric evaluation of composite materials with different thickness by reflectance spectroscopy  

Microsoft Academic Search

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

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



Nano composite phase change materials microcapsules  

NASA Astrophysics Data System (ADS)

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.

Song, Qingwen


Polyolefin composites containing a phase change material  


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.

Salyer, Ival O. (Dayton, OH)



Mechanical Spectroscopy of Nanostructured Composite Materials  

NASA Astrophysics Data System (ADS)

The thermo-mechanical behavior of different nano-structured composite materials, which were processed within the SAPHIR European Integrated Project, has been characterized by mechanical spectroscopy. The obtained results show clearly that creep resistance of fine grain ceramics such as zirconia can be improved by carbon nano-tube (CNT) reinforcements. On the other hand the elastic modulus and the damping capacity of aluminum matrix composites were increased by SiC nano-particle additions. It has also been observed that CNT additions are responsible for a better thermal stability of polymer such as ABS (Acrylonitrile-Butadiene-Styrene) used in automotive industry.

Mari, Daniele; Schaller, Robert; Mazaheri, Mehdi



Quantitative measurement of nanomechanical properties in composite materials  

NASA Astrophysics Data System (ADS)

In this work, quantitative Atomic force acoustic microscopy (AFAM) was used to measure nanomechanical properties and to determine microstructural morphology in fiber reinforced composites and hard calcified tissue. In carbon fiber reinforced composites, the fiber-matrix interphase is of interest as it affects the primary load-transfer process and thereby bulk mechanical properties of reinforced composites. The study of properties in the interphase region is important for an understanding of the bulk mechanical properties, which have been shown affected by moisture-based environmental degradation. Single point AFAM testing has been used to quantitatively determine elastic properties at the fiber-matrix interphase by taking advantage of the high spatial scanning resolution capable of measuring interphase dimensions. Carbon-fiber epoxy composite samples were degraded in laboratory conditions by exposure to a accelerated hydrothermal degradation environment in deionized water and salt water. Composite degradation has been characterized by the change in the epoxy matrix contact stiffness and the interphase properties. A decrease in matrix stiffness was found to coincide with the environmental exposure and moisture absorption of the samples. Interphase stiffness measurements indicate a constant interphase thickness as a function of environmental exposure. Chemical analysis of the epoxy using FTIR and Raman spectroscopy indicate hydrolysis of the C-O-C and Epoxide bonds which contribute to the decrease in epoxy mechanical properties. Accelerated degradation by salt water and deionized water both resulted in degradation of the epoxy, though the presence of sodium chloride showed less degradation. From SEM, debonding of the fiber-matrix interface was observed to be more severe when exposed to a salt water environment. In performing quantitative AFAM measurements, the effects of tip shape on the contact mechanics at the epoxy interface were found to influence the reported results significantly, and new, power-law body of revolution models of the probe tip geometry have been applied. Due to the low yield strength of polymers compared with other engineering materials, elastic-plastic contact is considered to better represent the epoxy surface response and was used to acquire more accurate quantitative measurements. Visco-elastic contact response was introduced in the boundary condition of the AFAM cantilever vibration model, due to the creep nature of epoxy, to determine time-dependent effects. These methods have direct impact on the quantitative measurement capabilities of near-filler interphase regions in polymers and composites and the long-term influence of environmental conditions on composites. In addition, quantitative AFAM scans were made on distal surfaces of human bicuspids and molars, to determine the microstructural and spatial variation in nanomechanical properties of the enamel biocomposite. Single point AFAM measurements were performed on individual enamel prism and sheath locations to determine spatial elastic modulus. Mechanical property variation of enamel is associated to the differences in the mineral to organic content and the apatite crystal orientations within the enamel microstructure. Also, variation in the elastic modulus of the enamel ultrastructure was observed in measurements at the outer enamel versus near the dentine enamel junction (DEJ).

Zhao, Wei


Four-photon spectroscopy of rotational transitions in liquid: recording of changes in the chemical composition of water caused by cavitation  

SciTech Connect

It is shown for the first time by the method of four-photon coherent scattering by rotational molecular resonances that the cavitation action on water changes its chemical composition, resulting in the formation of hydrogen peroxide. It is found that the concentration of hydrogen peroxide during cavitation grows by several times and depends on the cavitation process technology.

Bunkin, Aleksei F; Pershin, S M [Wave Research Center, A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)



Thin film dielectric composite materials  


A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

Jia, Quanxi (Los Alamos, NM); Gibbons, Brady J. (Los Alamos, NM); Findikoglu, Alp T. (Los Alamos, NM); Park, Bae Ho (Los Alamos, NM)



The filler content of the dental composite resins and their influence on different properties.  


The purpose of this study was to compare the inorganic content and morphology of one nanofilled and one nanohybrid composite with one universal microhybrid composite. The Vickers hardness, degree of conversion and scanning electron microscope of the materials light-cured using LED unit were also investigated. One nanofilled (Filtek™ Supreme XT), one nanohybrid (TPH®(3)) and one universal microhybrid (Filtek™ Z-250) composite resins at color A(2) were used in this study. The samples were made in a metallic mould (4 mm in diameter and 2 mm in thickness). Their filler weight content was measured by thermogravimetric analysis (TG). The morphology of the filler particles was determined using scanning electron microscope equipped with a field emission gun (SEM-FEG). Vickers hardness and degree of conversion using FT-IR spectroscopy were measured. Filtek™ Z-250 (microhybrid) composite resin shows higher degree of conversion and hardness than those of Filtek™ Supreme XT (nanofilled) and TPH®(3) (nanohybrid) composites, respectively. The TPH(3)® (nanohybrid) composite exhibits by far the lowest mechanical property. Nanofilled composite resins show mechanical properties at least as good as those of universal hybrids and could thus be used for the same clinical indications as well as for anterior restorations due to their high aesthetic properties. PMID:22213178

Rastelli, Alessandra N S; Jacomassi, Denis P; Faloni, Ana Paula S; Queiroz, Thallita P; Rojas, Seila S; Bernardi, Maria Inês B; Bagnato, Vanderlei S; Hernandes, Antônio C



Light-Weight Rigid Composite Materials Cured by Space Environment Factors  

NASA Astrophysics Data System (ADS)

This paper describes densely-packed materials that change their stiffness under exposure to ionizing radiation. The prepreg materials additionally curable under radiation exposure can be used for fabrication of large-size articles (e.g., supporting structures of large space antennas on space vehicles and aircraft, protective screens of spacecraft and protective structures on the Moon surface) transformed in a space environment (UV radiation, vacuum) and acquiring stiffness (shape stability) due to space factors. The materials additionally cured under radiation exposure can be obtained using specially developed complex binders with components of different sensitivity to ionizing radiation and curable via different mechanisms.

Laricheva, V. P.; Kalgashkina, G. V.; Korotkiy, A. F.; Shavarin, Yu. Ya.



GaN 1? x P x ternary alloys with high P composition grown by metal-organic chemical vapor deposition  

Microsoft Academic Search

GaN1?xPx ternary alloys with high P compositions were deposited on sapphire substrates by means of metal-organic chemical vapor deposition. Depth profiles of the elements indicate that the maximum P\\/N composition ratio is about 17% and a uniform distribution of the P atoms in the alloys is achieved. 2?\\/? XRD spectra demonstrate that the (0002) peak of the GaN1?xPx alloys shifts

D. J Chen; B Shen; Z. X Bi; K. X Zhang; S. L Gu; R Zhang; Y Shi; Y. D Zheng; X. H Sun; S. K Wan; Z. G Wang



Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites  

SciTech Connect

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.

Anderl, Robert Andrew; Pawelko, Robert James; Smolik, Galen Richard



The chemical composition of plant galls: are levels of nutrients and secondary compounds controlled by the gall-former?  

Microsoft Academic Search

The chemical composition of galled and ungalled plant tissue was compared in a series of experiments. Gall and adjacent plant\\u000a tissue was analysed for 20 species of gall-former on 11 different plant species. There were clear differences between galled\\u000a and ungalled tissue in levels of nutrients and secondary compounds. Gall tissue generally contained lower levels of nitrogen\\u000a and higher levels

S. E. Hartley



Composition and chemical reactions of titanium oxide films deposited by laser evaporation  

Microsoft Academic Search

Thin films were deposited on Pyrex glass substrates from Ti and TiO2 targets at room temperature by laser evaporation technique. These films were characterized by scanning electron microscopy, Auger electron spectroscopy, and depth profile analysis. The films deposited from Ti target are TiCx and TiOy matrix, while films from TiO2 target are almost stoichiometric in oxygen. The films have a

C. M. Dai; C. S. Su; D. S. Chuu



Flexure Tests of Three Fibrous Composite Materials.  

National Technical Information Service (NTIS)

Carbon and glass/ester composites were tested for flexural stiffness and strength. The test specimens were prepared from three types of composite materials: carbon fiber cloth/vinylester, glassfiber cloth/vinylester, and glassfiber/polyester in prepreg fo...

L. Knutsson H. Bjermert



Composite, Nanostructured, Super-Hydrophobic Material.  

National Technical Information Service (NTIS)

A hydrophobic disordered composite material having a protrusive surface feature includes a recessive phase and a protrusive phase, the recessive phase having a higher susceptibility to a preselected etchant than the protrusive phase, the composite materia...

B. R. D'Urso J. T. Simpson



Composite backfill materials for radioactive waste isolation by deep burial in salt  

SciTech Connect

Bentonite and hectorite were found to sorb Pu(IV) and Am(III) from concentrated brines with distribution coefficients K/sub d/ > 3000 ml/g. The permeability of bentonite to brine was less than 1 microdarcy at a confining pressure of 18 MPa, the expected lithostatic pressure at the 800 m level in a salt repository. Getters for sorption of TcO/sub 4//sup -/ (K/sub d/ approx. 300 ml/g), I/sup -/ (K/sub d/ greater than or equal to 30 ml/g), Cs (K/sub d/ greater than or equal to 30 ml/g) and Sr (K/sub d/ greater than or equal to approx. 100 ml/g) from brines were identified. Their sorption properties are presented. Thermal conductivity results (>0.5 W/mK) and evidence for bentonite stability in brines at hydrothermal conditions are also given. It is shown by calculated estimates that a 3-ft-thick mixture of bentonite with other getter materials could retain Pu, Am, and TcO/sub 4//sup -/ for >10/sup 4/ years and I/sup -/ for > 10/sup 3/ years. Another tailored mixture could retain Cs for approx. 600 years, Sr for approx. 700 years, TcO/sub 4/ for approx. 4000 years and I/sup -/ for approx. 400 years. The backfill can offer a significant contribution to the isolation capability of a waste package system.

Nowak, E.J.



Review on advanced composite materials boring mechanism and tools  

Microsoft Academic Search

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

Runping Shi; Chengyong Wang



The effect of age on 12 chemical element contents in the intact prostate of adult men investigated by inductively coupled plasma atomic emission spectrometry.  


The effect of age on 12 chemical element contents in intact prostate of 64 apparently healthy, 13-60-year-old men (mean age 36.5 years) was investigated by inductively coupled plasma atomic emission spectrometry. Mean values (M ± S??) for mass fraction (milligrams/kilogram, on dry weight basis) of Ba, Ca, Cu, Fe, K, Mg, Na, P, S, Sr, and Zn were: Ba 1.18 ± 0.12, Ca 2,178 ± 160, Cu 10.7 ± 0.9, Fe 122 ± 5, K 12,530 ± 360, Mg 1,100 ± 70, Na 10,470 ± 320, P 7,580 ± 300, S 8,720 ± 180, Sr 1.85 ± 0.28, and Zn 782 ± 97, respectively. The upper limit of mean content of V was ?0.22 mg/kg. A tendency of age-related increase in Ca, Fe, Na, and Zn mass fraction as well an increase in Zn/Ba, Zn/Ca, Zn/Cu, Zn/Fe, Zn/K, Zn/Mg, Zn/Na, Zn/P, Zn/S, and Zn/Sr ratios in prostate was observed. A significant positive correlation was seen between the prostatic zinc and Ca, Cu, Fe, Mg, Na, and P contents. PMID:22231436

Zaichick, Vladimir; Nosenko, Sergey; Moskvina, Irina



Conductor-polymer composite electrode materials  


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.

Ginley, D.S.; Kurtz, S.R.; Smyrl, W.H.; Zeigler, J.M.



Visualising chemical composition and reaction kinetics by the near infrared multispectral imaging technique  

Microsoft Academic Search

A new multispectral imaging spectrometer which is capable of simultaneously recording spectral images in the visible and near infrared has been developed. In this instrument, an acousto-optic tunable filter (AOTF) is used to diffract an unpolarised incident light into two diffracted beams with orthogonal polarisation. One of the beams is detected by a sil- icon camera for the visible region

Chieu D. Tran



Dielectric Properties of Sweet Potato Purees at 915 MHz as Affected by Temperature and Chemical Composition  

Microsoft Academic Search

A process for rapid sterilization and aseptic packaging of sweet potato puree using a continuous flow microwave system operating at 915 MHz has been successfully developed. In microwave processing, dielectric properties have a major role in determining the interaction between purees and the electromagnetic energy. The objective of this research was to determine how dielectric properties are affected by temperature

T. A. Brinley; V. D. Truong; P. Coronel; J. Simunovic; K. P. Sandeep



Chemical composition and heterogeneity of Wild 2 cometary particles determined by synchrotron X-ray fluorescence  

Microsoft Academic Search

Seven cometary dust particle tracks in Stardust aerogel were studied using synchrotron X-ray fluorescence methods at the National Synchrotron Light Source (NY) and Advanced Photon Source (IL). Elemental maps were produced for each of the tracks and elemental abundances for 156 individual fragments within these tracks were determined. Whole-track elemental abundances were inferred by summing the elemental masses for the

A. Lanzirotti; S. R. Sutton; G. J. Flynn; M. Newville; W. Rao



Chemical composition of ZrC thin films grown by pulsed laser deposition  

Microsoft Academic Search

ZrC films were grown on (100) Si substrates by the pulsed laser deposition (PLD) technique using a KrF excimer laser working at 40Hz. The nominal substrate temperature during depositions was set at 300°C and the cooling rate was 5°C\\/min. X-ray diffraction investigations showed that films deposited under residual vacuum or under 2×10?3Pa of CH4 atmosphere were crystalline, exhibiting a (200)-axis

D. Craciun; G. Socol; N. Stefan; G. Bourne; V. Craciun



Dynamic compaction of particulate composite materials  

NASA Astrophysics Data System (ADS)

This paper describes the mechanical alloying + dynamic compaction flowchart for producing composites with particulate reinforcements. The combinations of components tested included aluminum silicon carbide, aluminum boron carbide, copper silicon carbide, and copper silica. Mechanical alloying produced granules of composite with reinforcements uniformly distributed in the matrix material. Dynamic compaction of mechanically alloyed granules was shown to produce high quality composite materials with crack-free structure. As the standard methods for explosive treatment lead to crack formation in bulk composites, this work included the development of a tool for treating composite materials.

Popov, V. A.; Staudhammer, K. P.; Goulbin, V. N.



Conifer seeds: Oil content and fatty acid composition  

Microsoft Academic Search

The seed oils from twenty-five Conifer species (from four families—Pinaceae, Cupressaceae, Taxodiaceae, and Taxaceae) have\\u000a been analyzed, and their fatty acid compositions were established by capillary gas-liquid chromatography on two columns with\\u000a different polarities. The oil content of the seeds varied from less than 1% up to 50%. Conifer seed oils were characterized\\u000a by the presence of several ?5-unsaturated polymethylene-interrupted

Robert L. Wolff; Laurent G. Deluc; Anne M. Marpeau



Chemical composition and starch digestibility in flours from Polish processed legume seeds.  


The study was undertaken to determine the effect of various treatments, i.e. cooking after soaking, freezing after cooking and storage at a low temperature (-18°C, 21days), and autoclaving, of Polish cultivars of bean, pea and lentil seeds on the chemical composition and starch digestibility of the resultant flours. The cooking of seeds caused a significant decrease in contents of ash (by 11-48%), polyphenols (by 10-70%) and protein (to 19%) in flours made of bean. In addition, analyses demonstrated significantly decreased contents of resistant starch, RS (by 61-71%) and slowly digestible starch, SDS (by 56-84%). Storage of frozen seeds resulted in insignificant changes in the chemical composition, and in increased contents of both RS and SDS. The flours produced upon the autoclaving process were characterized by similar changes in the contents of ash and protein as in cooked seeds, yet losses of polyphenols were lower and, simultaneously, contents of RS and SDS were higher. All the analyzed flours were shown to be characterized by a reduced content of amylose in starch, which might have affected its digestibility. This was indicated by a strict negative correlation reported between the value of the starch digestion index (SDRI) and amylose content of starch (r=0.84, p>0.05). PMID:22953824

Piecyk, Ma?gorzata; Wo?osiak, Rafa?; Dru?ynska, Beata; Worobiej, Elwira



Physical Morphology and Quantitative Characterization of Chemical Changes of Weathered PVC/Pine Composites.  

National Technical Information Service (NTIS)

This study investigated weathering effects on polyvinyl chloride (PVC) based wood plastic composites (WPC), with a focus on the color and structure that is attributed to the material composition. It is directed towards quantifying the main chemical modifi...

A. G. McDonald J. S. Fabiyi



Chemical vapor composite silicon carbide for space telescopes  

Microsoft Academic Search

Components for space telescopes using high quality silicon carbide (SiC) produced via the chemical vapor composite (CVC) process are currently under development. This CVC process is a modification of chemical vapor deposition (CVD) and results in a dramatic reduction in residual stress of the SiC deposit. The resultant CVC SiC material has high modulus, high thermal conductivity and can be

C. T. Tanaka; K. Webb



Electroless recovery of silver by inherently conducting polymer powders, membranes and composite materials  

Microsoft Academic Search

A wide variety of inherently conducting polymers, including polypyrroles and polyanilines, were shown to reduce silver ion in aqueous solution, demonstrating that these materials may form the basis of a novel approach to silver recovery. The effect of varying the polymer, dopant, and underlying substrate (reticulated vitreous carbon or fabric) was investigated, as was the effect of changing the pH

Roza Dimeska; Paul S. Murray; Stephen F. Ralph; Gordon G. Wallace



Development of composite materials by mechanochemical treatment of post-consumer plastic waste  

Microsoft Academic Search

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

F Cavalieri; F Padella



[Study of the feasibility and conditions for disinfecting materials made of chemical fibers by immersion in solutions of several disinfectants].  


The authors studied the disinfection regimens of materials made of lavsan, capron, acetate, triacetate, viscose by the method of immersion into the disinfecting solutions of dichlor-I, chloramine calcium hypochlorite salt, potassium and sodium salt of dichlorisocianuric acid, sulfochloranthin, dichlordimethylhydantoin, catapin, amphocept, sodium metasilicate, hydrogen, peroxide, formalin, phenol, benzylphenol. As revealed, solutions of the following preparations could be recommended for the disinfection of linen made of chemical fibers at the foci of intestinal and droplet infection, except tuberculosis: sulfochloranthin (0.2%), amphocept and chloramine B (1%), sodium metasilicate, formalin, catapin, hydrogen peroxide with a 0.5% of washing solution (2%); these solutions gave a reliable effect in 60 minutes at room temperature, and in 20 to 30 minutes at a temperature of 40--45 degrees C. PMID:919913

Alen'kin, B F; Rumiantseva, T A; Shiriaeva, M G



The effect of age and gender on 38 chemical element contents in human femoral neck investigated by instrumental neutron activation analysis.  


The effect of age and gender on 38 chemical element contents in femoral neck of 85 apparently healthy 15-55-year-old women (n = 38) and men (n = 47) was investigated by instrumental neutron activation analysis. Mean values (M +/- SEpsilonMu) for mass fraction (on dry weight basis) of Ca, Cl, Co, Fe, K, Mg, Mn, Na, P, Sr, and Zn for both female and male taken together were: Ca 153 +/- 3 g/kg, Cl 1,188 +/- 48 mg/kg, Co 0.0039 +/- 0.0004 mg/kg, Fe 55.5 +/- 8.8 mg/kg, K 490 +/- 22 mg/kg, Mg 1,940 +/- 48 mg/kg, Mn 0.385 +/- 0.015 mg/kg, Na 3,850 +/- 70 mg/kg, P 73.0 +/- 1.5 g/kg, Sr 288 +/- 18 mg/kg, and Zn 55.5 +/- 1.6 mg/kg, respectively. The upper limit of mean contents of Cr, Cs, Eu, Hg, Rb, Sb, Sc, and Se were: Cr < or = 0.2, Cs < or = 0.02, Eu < or = 0.007, Hg < or = 0.006, Rb < or = 0.8, Sb < or = 0.02, Sc < or = 0.0004, and Se < or = 0.06 mg/kg, respectively. In all bone samples, the contents of Ag, As, Au, Ba, Br, Cd, Ce, Gd, Hf, La, Lu, Nd, Sm, Ta, Tb, Th, U, Yb, and Zr were under detection limits. The Ca, Mg, and P contents decrease with age. Higher Ca, Cl, K, Mg, Mn, Na, and Sr mass fractions are typical of female femoral neck as compared to those in male bone. PMID:19898755

Zaichick, Sofia; Zaichick, Vladimir



Hydrogel Composite Materials for Tissue Engineering Scaffolds  

NASA Astrophysics Data System (ADS)

Hydrogels are appealing for biomaterials applications due to their compositional similarity with highly hydrated natural biological tissues. However, for structurally demanding tissue engineering applications, hydrogel use is limited by poor mechanical properties. Here, composite materials approaches are considered for improving hydrogel properties while attempting to more closely mimic natural biological tissue structures. A variety of composite material microstructures is explored, based on multiple hydrogel constituents, particle reinforcement, electrospun nanometer to micrometer diameter polymer fibers with single and multiple fiber networks, and combinations of these approaches to form fully three-dimensional fiber-reinforced hydrogels. Natural and synthetic polymers are examined for formation of a range of scaffolds and across a range of engineered tissue applications. Following a discussion of the design and fabrication of composite scaffolds, interactions between living biological cells and composite scaffolds are considered across the full life cycle of tissue engineering from scaffold fabrication to in vivo use. We conclude with a summary of progress in this area to date and make recommendations for continuing research and for advanced hydrogel scaffold development.

Shapiro, Jenna M.; Oyen, Michelle L.



Chemical compositions responsible for inflammation and tissue damage in the mouse lung by coarse and fine particulate samples from contrasting air pollution in Europe  

SciTech Connect

Inflammation is regarded as an important mechanism in mortality and morbidity associated with exposures of cardiorespiratory patients to urban air particulate matter. We investigated the association of the chemical composition and sources of urban air fine (PM2.5-0.2) and coarse (PM10-2.5) particulate samples with the inflammatory activity in the mouse lung. The particulate samples were collected during selected seasons in six European cities using a high-volume cascade impactor. Healthy C57BL/6J mice were intratracheally instilled with a single dose (10 mg/kg) of the particulate samples. At 4, 12, and 24 h after the exposure, the lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: cell number, total protein, and cytokines (tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and KC). Dicarboxylic acids and transition metals, especially Ni and V, in PM2.5-0.2 correlated positively and some secondary inorganic ions (NO{sub 3}{sup -}, NH{sub 4}{sup +}) negatively with the inflammatory activity. Total organic matter and SO{sub 4}{sup 2-} had no consistent correlations. In addition, the soil-derived constituents (Ca{sup 2+}, Al, Fe, Si) showed positive correlations with the PM2.5-0.2-induced inflammatory activity, but their role in PM10 (2.5) remained obscure, possibly due to largely undefined biogenic material. Markers of poor biomass and coal combustion, i.e., monosaccharide anhydrides and As, were associated with elevated PAH contents in PM2.5 (0.2) and a consistent immunosuppressive effect. Overall, our results support epidemiological findings that the local sources of incomplete combustion and resuspended road dust are important in urban air particulate pollution-related health effects.

Happo, M.S.; Hirvonen, M.R.; Halinen, A.I.; Jalava, P.I.; Pennanen, A.S.; Sillanpaa, M.; Hillamo, R.; Salonen, R.O. [National Public Health Institute, Kuopio (Finland). Dept. of Environmental Health



The determination of the chemical composition profile of the GaAs/AlGaAs heterostructures designed for quantum cascade lasers by means of synchrotron radiation  

NASA Astrophysics Data System (ADS)

The chemical composition profile of the GaAs/AlGaAs quantum cascade structures grown on (0 0 1) GaAs substrate by molecular beam epitaxy is studied by a synchrotron radiation high-resolution X-ray diffraction. The analysis is carried out for the whole structure as well for its parts. In order to determine some structural parameters, such as: the thickness and chemical composition of each layer making up the investigated structure, the profile of the interface between succeeding layers, and the preservation of the structure periodicity, the experimental X-ray diffraction profiles are compared with simulated ones calculated by means of Darwin dynamical theory of X-ray diffraction. It is shown that this method gives correct chemical composition profiles and allows for the evaluation of the deviations from the designed values of the structural parameters in most investigated cases. Limits of the method are discussed, especially by the determination of the chemical composition profile for thin heterostructures, such as those making active or injector regions.

Gaca, Jaros?aw; Wójcik, Marek; Bugajski, Maciej; Kosiel, Kamil



Reactive amine surfaces for biosensor applications, prepared by plasma-enhanced chemical vapour modification of polyolefin materials.  


Here we have demonstrated a solventless plasma-based process that integrates low-cost, high throughput, high reproducibility and ecofriendly process for the functionalization of the next-generation point-of-care device platforms. Amine functionalities were deposited by plasma-enhanced chemical vapour deposition (PECVD) using a new precursor. The influence of the plasma RF power and the deposition time on surfacial properties, as well as their effect on the reactivity and content of amino groups was investigated. The key process determinants were to have a sufficient power in the plasma to activate and partially fragment the monomer but not too much as to lose the reactive amine functionality, and sufficient deposition time to develop a reactive layer but not to consume or erode the amine reactivity. An immunoassay performed using human immunoglobulin (IgG) as a model analyte showed an improvement of the detection limit by two orders of magnitude beyond that obtained using devices activated by liquid-phase reaction. PMID:20117925

Volcke, C; Gandhiraman, R P; Gubala, V; Raj, J; Cummins, Th; Fonder, G; Nooney, R I; Mekhalif, Z; Herzog, G; Daniels, S; Arrigan, D W M; Cafolla, A A; Williams, D E



Reinforced polypropylene composites: effects of chemical compositions and particle size.  


In this work, the effects of wood species, particle sizes and hot-water treatment on some physical and mechanical properties of wood-plastic composites were studied. Composites of thermoplastic reinforced with oak (Quercus castaneifolia) and pine (Pinus eldarica) wood were prepared. Polypropylene (PP) and maleic anhydride grafted polypropylene (MAPP) were used as the polymer matrix and coupling agent, respectively. The results showed that pine fiber had significant effect on the mechanical properties considered in this study. This effect is explained by the higher fiber length and aspect ratio of pine compared to the oak fiber. The hot-water treated (extractive-free) samples, in both wood species, improved the tensile, flexural and impact properties, but increased the water absorption for 24h. This work clearly showed that lignocellulosic materials in both forms of fiber and flour could be effectively used as reinforcing elements in PP matrix. Furthermore, extractives have marked effects on the mechanical and physical properties. PMID:19948401

Ashori, Alireza; Nourbakhsh, Amir



Nickel composite magnetostrictive material research for ultrasonic transducer  

Microsoft Academic Search

The immediate objective was to manufacture and test a composite transducer material of the compound SmFe2 in a nickel matrix fabricated by a powder metallurgy technique. The long term objective was the effective utilization of a 'giant' magnetostrictive REFe2 material in a ductile and corrosion resistant composite for use as a transducer core material.

D. T. Peters; E. L. Huston



Composite Materials with Improved Properties in Compression.  

National Technical Information Service (NTIS)

Preparation of composite materials which have high strength in compression. Scientific approach is to prepare novel polymeric coupling agents. These will permit formation of multiple flexible covalent bonds between fibers as well as to matrix materials. I...

W. P. Weber



Comparative Analysis of the Chemical Composition of Mixed and Pure Cultures of Green Algae and Their Decomposed Residues by 13C Nuclear Magnetic Resonance Spectroscopy  

PubMed Central

It is known that macromolecular organic matter in aquatic environments, i.e., humic substances, is highly aliphatic. These aliphatic macromolecules, predominantly paraffinic in structure, are prevalent in marine and lacustrine sediments and are believed to originate from algae or bacteria. A comparative study of mixed and pure cultures of green algae and their decomposed residues was performed by using solid-state 13C nuclear magnetic resonance spectroscopy as the primary analytical method. Results obtained in this study confirm the presence of components that are chemically refractory and that are defined as alghumin and hydrolyzed alghumin. These were detected in heterogeneous, homogeneous, and axenic biomasses composed of several genera of Chlorophyta. Although the chemical composition of algal biomass varied with culture conditions, the chemical structure of the alghumin and hydrolyzed alghumin, demonstrated by 13C nuclear magnetic resonance spectroscopy appeared to be constant for members of the Chlorophyta examined in this study. The alghumin was dominated by carbohydrate-carbon, with minor amounts of amide or carboxyl carbon and paraffinic carbon, the latter surviving strong hydrolysis by 6 N HCI (hydrolyzed alghumin). Bacterial decomposition of heterogeneous algal biomass labeled with 13C was conducted under both aerobic and anaerobic conditions to determine chemical structure and stability of the refractory material. The refractory fraction ranged from 33% in aerobic to 44% in anaerobic cultures. The refractory fraction recovered from either aerobic or anaerobic degradation comprised 40% alghumin, which represented an enrichment by 10% relative to the proportion of alghumin derived from whole cells of algae. The paraffinic component in the hydrolyzed alghumin of whole algal cells was found to be 1.8% and increased to 5.1 and 6.9% after aerobic and anaerobic bacterial degradation, respectively. It is concluded that members of the Chlorophyta contain a common insoluble structure composed of paraffinic carbon that is resistant to chemical and bacterial degradation under conditions used in this study. The paraffinic structure is identical to those constituting humin of aquatic origin. Thus, alga-derived macromolecular compounds deposited in aquatic environments (alghumin) probably contribute to sedimentary humic substances.

Zelibor, J. L.; Romankiw, L.; Hatcher, P. G.; Colwell, R. R.



Ferromanganese nodules from MANOP Sites H, S, and R-Control of mineralogical and chemical composition by multiple accretionary processes  

USGS Publications Warehouse

The chemical composition of ferromanganese nodules from the three nodule-bearing MANOP sites in the Pacific can be accounted for in a qualitative way by variable contributions of distinct accretionary processes. These accretionary modes are: 1. (1) hydrogenous, i.e., direct precipitation or accumulation of colloidal metal oxides in seawater, 2. (2) oxic diagenesis which refers to a variety of ferromanganese accretion processes occurring in oxic sediments; and 3. (3) suboxic diagenesis which results from reduction of Mn+4 by oxidation of organic matter in the sediments. Geochemical evidence suggests processes (1) and (2) occur at all three MANOP nodule-bearing sites, and process (3) occurs only at the hemipelagic site, H, which underlies the relatively productive waters of the eastern tropical Pacific. A normative model quantitatively accounts for the variability observed in nearly all elements. Zn and Na, however, are not well explained by the three end-member model, and we suggest that an additional accretionary process results in greater variability in the abundances of these elements. Variable contributions from the three accretionary processes result in distinct top-bottom compositional differences at the three sites. Nodule tops from H are enriched in Ni, Cu, and Zn, instead of the more typical enrichments of these elements in nodule bottoms. In addition, elemental correlations typical of most pelagic nodules are reversed at site H. The three accretionary processes result in distinct mineralogies. Hydrogenous precipitation produces ??MnO2. Oxic diagenesis, however, produces Cu-Ni-rich todorokite, and suboxic diagenesis results in an unstable todorokite which transforms to a 7 A?? phase ("birnessite") upon dehydration. The presence of Cu and Ni as charge-balancing cations influence the stability of the todorokite structure. In the bottoms of H nodules, which accrete dominantly by suboxic diagenesis, Na+ and possibly Mn+2 provide much of the charge balance for the todorokite structure. Limited growth rate data for H nodules suggest suboxic accretion is the fastest of the three processes, with rates at least 200 mm/106 yr. Oxic accretion is probably 10 times slower and hydrogenous 100 times slower. Since these rates predict more suboxic component in bulk nodules than is calculated by the normative analysis, we propose that suboxic accretion is a non-steady-state process. Variations in surface water productivity cause pulses of particulate flux to the sea floor which result in transient Mn reduction in the surface sediments and reprecipitation on nodule surfaces. ?? 1984.

Dymond, J.; Lyle, M.; Finney, B.; Piper, D. Z.; Murphy, K.; Conard, R.; Pisias, N.



The chemical and hydrological evolution of an ancient potash-forming evaporite basin as constrained by mineral sequence, fluid inclusion composition, and numerical simulation  

Microsoft Academic Search

The chemical evolution of the brine in a potash evaporite basin has been investigated by X-ray microanalysis of frozen primary inclusions trapped in halite. A Computer program based on thermodynamic equilibrium and mass balance principles has been used to simulate evaporation paths. The comparison between the results of calculations, the observed mineralogy and mineral sequence, and the solute content in

Carlos Ayora; Javier Garcia-Veigas; Juan-Jose Pueyo



Chemical evolution of Macondo crude oil during laboratory degradation as characterized by fluorescence EEMs and hydrocarbon composition.  


The fluorescence EEM technique, PARAFAC modeling, and hydrocarbon composition were used to characterize oil components and to examine the chemical evolution and degradation pathways of Macondo crude oil under controlled laboratory conditions. Three major fluorescent oil components were identified, with Ex/Em maxima at 226/328, 262/315, and 244/366 nm, respectively. An average degradation half-life of ?20 d was determined for the oil components based on fluorescence EEM and hydrocarbon composition measurements, showing a dynamic chemical evolution and transformation of the oil during degradation. Dispersants appeared to change the chemical characteristics of oil, to shift the fluorescence EEM spectra, and to enhance the degradation of low-molecular-weight hydrocarbons. Photochemical degradation played a dominant role in the transformation of oil components, likely an effective degradation pathway of oil in the water column. Results from laboratory experiments should facilitate the interpretation of field-data and provide insights for understanding the fate and transport of oil components in the Gulf of Mexico. PMID:23174304

Zhou, Zhengzhen; Liu, Zhanfei; Guo, Laodong



Oxidation level-dependent zwitterionic liposome adsorption and rupture by graphene-based materials and light-induced content release.  


Liposomes may be stably adsorbed or ruptured on graphene-based materials, depending on the oxidation state of graphene. IR-induced liposome leakage is achieved, since graphene oxide does not induce liposome leakage spontaneously. PMID:23239613

Ip, Alexander C-F; Liu, Biwu; Huang, Po-Jung Jimmy; Liu, Juewen



NDE of polymeric composite material bridge components  

NASA Astrophysics Data System (ADS)

Rapid advancements with respect to utilization of polymeric composite materials for bridge components is occurring. This situation is driven primarily by the potential improvements offered by these materials with respect to long term durability. However, because of the developmental nature of these materials much of the materials characterization has involved short term testing without the synergistic effects of environmental exposure. Efforts to develop nondestructive evaluation procedures, essential for any wide spread use in critical structural applications, have been consequently limited. This paper discuses the effort to develop NDE methods for field inspection of hybrid glass and carbon fiber reinforced vinyl ester pultruded 'double box' I beams that are installed in a small bridge over Tom's Creek, in Blacksburg, Virginia. Integrated structural element sensors, dormant infrared devices, as well as acousto-ultrasonic methods are under development for detecting and monitoring the occurrence and progression of life limiting deterioration mechanisms.

Duke, John C.; Horne, Michael R.



Chemical and mineralogical characterization of archaeologicam building materials from Seyitomer Hoyuk Kutahya, Turkey.  

NASA Astrophysics Data System (ADS)

This paper focuses on the spectroscopic and thermal analysis of the archaeological samples of mortar and plaster from middle Bronze Age and Achaemenid period in Seyitömer Höyük. The composition of the samples was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric thermal analysis (TG-DTA). The results showed that human used different types of raw materials in the preperation of the mortar and plaster in the Middle Bronze Age and Achaemenid period. The material used in middle Bronze Age contains muscovite whereas the material in Achaemenid period contains albite. Although, the chemical composition of the mortar and plaster used in the period were similar, the calcium content of the plaster is relatively higher than the one of the mortar indicating people's awareness of the binding properties of calcite.

Bilgen, Nejat; Olgun, Asim


Optical band gaps and composition dependence of hafnium-aluminate thin films grown by atomic layer chemical vapor deposition  

SciTech Connect

We report the optical properties of unannealed hafnium-aluminate (HfAlO) films grown by atomic layer chemical vapor deposition (ALCVD) and correlate them with the aluminum contents in the films. Vacuum ultraviolet spectroscopic ellipsometry (VUV-SE), high-resolution transmission electron microscopy (HRTEM), channeling Rutherford backscattering spectrometry (RBS), and resonant nuclear reaction analysis (NRA) were employed to characterize these films. In the analyses of ellipsometry data, a double Tauc-Lorentz dispersion produces a best fit to the experimental VUV-SE data. As a result, the determined complex pseudodielectric <{epsilon}> functions of the films clearly exhibit a dependency on the aluminum densities measured by RBS and NRA. We show that the optical fundamental band gap E{sub g} shifts from 5.56{+-}0.05 eV for HfO{sub 2} to 5.92{+-}0.05 eV for HfAlO. The latter was grown by using an equal number of pulses of H{sub 2}O/HfCl{sub 4} and H{sub 2}O/TMA (trimethylaluminum) precursors in each deposition cycle for HfO{sub 2} and Al{sub 2}O{sub 3}, respectively. The shift of E{sub g} to higher photon energies with increasing aluminum content indicates that intermixing of HfO{sub 2} and Al{sub 2}O{sub 3} occurred during the ALCVD growth process. We found that E{sub g} varies linearly with the mole fraction x of Al{sub 2}O{sub 3} in the alloy (HfO{sub 2}){sub x}(Al{sub 2}O{sub 3}){sub 1-x}, but has a parabolic dependency with the aluminum density. We also observed a consistent decrease in the magnitudes of the real <{epsilon}{sub 1}> and imaginary <{epsilon}{sub 2}> part of <{epsilon}> of HfAlO films with respect to those of HfO{sub 2} as the Al density increased. The absence of the {approx_equal}5.7 eV peak in the <{epsilon}> spectrum, which was previously reported for polycrystalline HfO{sub 2} films, indicates that these films are amorphous as confirmed by their HRTEM images.

Nguyen, N.V.; Sayan, S.; Levin, I.; Ehrstein, J.R.; Baumvol, I.J.R.; Driemeier, C.; Krug, C.; Wielunski, L.; Hung, P.Y.; Diebold, Alain [Semiconductor Electronics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Department of Chemistry, Rutgers University, Piscataway, New Jersey 08854 (United States); Ceramics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Semiconductor Electronics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Instituto de Fisica, UFRGS, 91509-900 Porto Alegre, RS (Brazil); Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States); International Sematech, Austin, Texas 78741 (United States)



Chemical Compositions of Diffuse Nebulae.  

National Technical Information Service (NTIS)

Our solar system is presumed to have been formed from the interstellar medium, presumably material very similar to what is now found in diffuse nebulae such as that of Orion. The methods of abundance determination differ considerably from those employed f...

L. H. Aller



Chemical composition of suspended sediments in World Rivers: New insights from a new database  

Microsoft Academic Search

The aim of this paper is to present a new database on the chemical composition of suspended matter in World Rivers, together with the associated elemental fluxes. There is a lack of any recent attempt in the literature to update the pioneering work of Martin and Meybeck [Martin, J.-M., Meybeck, M., 1979. Elemental mass balance of material carried by major

Jérôme Viers; Bernard Dupré; Jérôme Gaillardet



The ideal ceramic-fibre\\/oxide-matrix composite: how to reconcile antagonist physical and chemical requirements?  

Microsoft Academic Search

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 \\

Philippe Colomban; Gwénael Gouadec



Synthesis and physico-chemical characterization of a polysialate-hydroxyapatite composite for potential biomedical application  

NASA Astrophysics Data System (ADS)

New composite materials based on aluminosilicate materials were developed to be used in orthopaedic or maxillo-facial surgery. They are called geopolymers or polysialate-siloxo (PSS) and were studied alone or mixed with hydroxyapatite (HAP). The properties of these materials were investigated for potential use in biological or surgery applications. In this work, the chemistry involved in materials preparation was described. Samples were characterized by some physico-chemical methods like X-ray diffraction (XRD), infrared spectrometry (IR) and electron dispersion X-ray spectrometry (EDX). Results indicate that the mixing hydroxyapatite-geopolymer (PSS) leads to a neutral porous composite material with interesting physico-chemical properties. A preliminary evaluation of its cytotoxicity reveals an harmlessness towards fibroblasts. These properties allow to envisage this association as a potential biomaterial.

Zoulgami, M.; Lucas-Girot, A.; Michaud, V.; Briard, P.; Gaudé, J.; Oudadesse, H.



Novel materials and device design by metal-organic chemical vapor deposition for use in infrared emitters  

SciTech Connect

The authors have grown AlSb and AlAs{sub x}Sb{sub 1{minus}x} epitaxial layers by metal-organic chemical vapor deposition(MOCVD) using trimethylamine or ethyldimethylamine alane, triethylantimony an