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Sample records for chemical composition by material content

  1. Temperature response of litter and soil organic matter decomposition is determined by chemical composition of organic material

    NASA Astrophysics Data System (ADS)

    Erhagen, B.; Oquist, M. G.; Sparrman, T.; Haei, M.; Ilstedt, U.; Hedenstrm, M.; Schleucher, J.; Nilsson, M. B.

    2013-12-01

    The global soil carbon pool is approximately three times larger than the contemporary atmospheric pool, therefore even minor changes to its integrity may have major implications for atmospheric CO2 concentrations. While theory predicts that the chemical composition of organic matter should constitute a master control on the temperature response of its decomposition, this relationship has not yet been fully demonstrated. We used laboratory incubations of forest soil organic matter (SOM) and fresh litter material together with NMR spectroscopy to make this connection between organic chemical composition and temperature sensitivity of decomposition. Temperature response of decomposition in both fresh litter and SOM was directly related to the chemical composition of the constituent organic matter, explaining 90% and 70% of the variance in Q10 in litter and SOM respectively. The Q10 of litter decreased with increasing proportions of aromatic and O-aromatic compounds, and increased with increased contents of alkyl- and O-alkyl carbons. In contrast, in SOM, decomposition was affected only by carbonyl compounds. To reveal why a certain group of organic chemical compounds affected the temperature sensitivity of organic matter decomposition in litter and SOM, a more detailed characterisation of the 13C aromatic region using Heteronuclear Single Quantum Coherence (HSQC) was conducted. The results revealed considerable differences in the aromatic region between litter and SOM. This suggests that the correlation between chemical composition of organic matter and the temperature response of decomposition differed between litter and SOM. The temperature response of soil decomposition processes can thus be described by the chemical composition of its constituent organic matter, this paves the way for improved ecosystem modelling of biosphere feedbacks under a changing climate.

  2. Temperature response of litter and soil organic matter decomposition is determined by chemical composition of organic material.

    PubMed

    Erhagen, Bjrn; quist, Mats; Sparrman, Tobias; Haei, Mahsa; Ilstedt, Ulrik; Hedenstrm, Mattias; Schleucher, Jrgen; Nilsson, Mats B

    2013-12-01

    The global soil carbon pool is approximately three times larger than the contemporary atmospheric pool, therefore even minor changes to its integrity may have major implications for atmospheric CO2 concentrations. While theory predicts that the chemical composition of organic matter should constitute a master control on the temperature response of its decomposition, this relationship has not yet been fully demonstrated. We used laboratory incubations of forest soil organic matter (SOM) and fresh litter material together with NMR spectroscopy to make this connection between organic chemical composition and temperature sensitivity of decomposition. Temperature response of decomposition in both fresh litter and SOM was directly related to the chemical composition of the constituent organic matter, explaining 90% and 70% of the variance in Q10 in litter and SOM, respectively. The Q10 of litter decreased with increasing proportions of aromatic and O-aromatic compounds, and increased with increased contents of alkyl- and O-alkyl carbons. In contrast, in SOM, decomposition was affected only by carbonyl compounds. To reveal why a certain group of organic chemical compounds affected the temperature sensitivity of organic matter decomposition in litter and SOM, a more detailed characterization of the (13) C aromatic region using Heteronuclear Single Quantum Coherence (HSQC) was conducted. The results revealed considerable differences in the aromatic region between litter and SOM. This suggests that the correlation between chemical composition of organic matter and the temperature response of decomposition differed between litter and SOM. The temperature response of soil decomposition processes can thus be described by the chemical composition of its constituent organic matter, this paves the way for improved ecosystem modeling of biosphere feedbacks under a changing climate. PMID:23907960

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

    SciTech Connect

    1998-10-05

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

  4. Estimation of Macronutrient Content in Kindergartens Meals: Food Composition Tables or Chemical Analysis?

    PubMed Central

    Konstansa, Lazarevic; Dusica, Stojanovic; Dragan, Bogdanovic

    2014-01-01

    Objective: The nutrition of children in kindergartens has a great significance for proper growth and development of children. In order to save time and money, the control of macronutrients content is performed by calculations using food composition tables instead of performing a chemical analysis. Methods: We examined the macronutrients content of 240 whole day meals using food composition tables and performed chemical analysis of meals to determine adequacy and validity of food composition tables in calculation of macronutrient contents in kindergarten meals. Findings: We established no correlation (P>0.05) between the value of proteins, fats and carbohydrates. Significant difference was established between the average content of proteins (t=2.57; P<0.05), and carbohydrates (t=3.20; P<0.01), but not with the content of fats in the meals (t=1.26; P>0.05) (food composition tables vs chemical analysis). Conclusion: Until we establish new food composition tables, chemical analysis remains the only valid method for assessment of macronutrients content and energy value of a meal in kindergarten. PMID:25793075

  5. Functional composite materials based on chemically converted graphene.

    PubMed

    Bai, Hua; Li, Chun; Shi, Gaoquan

    2011-03-01

    Graphene, a one-atom layer of graphite, possesses a unique two-dimensional structure and excellent mechanical, thermal, and electrical properties. Thus, it has been regarded as an important component for making various functional composite materials. Graphene can be prepared through physical, chemical and electrochemical approaches. Among them, chemical methods were tested to be effective for producing chemically converted graphene (CCG) from various precursors (such as graphite, carbon nanotubes, and polymers) in large scale and at low costs. Therefore, CCG is more suitable for synthesizing high-performance graphene based composites. In this progress report, we review the recent advancements in the studies of the composites of CCG and small molecules, polymers, inorganic nanoparticles or other carbon nanomaterials. The methodology for preparing CCG and its composites has been summarized. The applications of CCG-based functional composite materials are also discussed. PMID:21360763

  6. Chemical composition and enzymatic digestibility of sugarcane clones selected for varied lignin content

    PubMed Central

    2011-01-01

    Background The recalcitrance of lignocellulosic materials is a major limitation for their conversion into fermentable sugars. Lignin depletion in new cultivars or transgenic plants has been identified as a way to diminish this recalcitrance. In this study, we assessed the success of a sugarcane breeding program in selecting sugarcane plants with low lignin content, and report the chemical composition and agronomic characteristics of eleven experimental hybrids and two reference samples. The enzymatic digestion of untreated and chemically delignified samples was evaluated to advance the performance of the sugarcane residue (bagasse) in cellulosic-ethanol production processes. Results The ranges for the percentages of glucan, hemicellulose, lignin, and extractive (based on oven-dry biomass) of the experimental hybrids and reference samples were 38% to 43%, 25% to 32%, 17% to 24%, and 1.6% to 7.5%, respectively. The samples with the smallest amounts of lignin did not produce the largest amounts of total polysaccharides. Instead, a variable increase in the mass of a number of components, including extractives, seemed to compensate for the reduction in lignin content. Hydroxycinnamic acids accounted for a significant part of the aromatic compounds in the samples, with p-coumaric acid predominating, whereas ferulic acid was present only in low amounts. Hydroxycinnamic acids with ester linkage to the hemicelluloses varied from 2.3% to 3.6%. The percentage of total hydroxycinnamic acids (including the fraction linked to lignin through ether linkages) varied from 5.0% to 9.2%, and correlated to some extent with the lignin content. These clones released up to 31% of glucose after 72 hours of digestion with commercial cellulases, whereas chemically delignified samples led to cellulose conversion values of more than 80%. However, plants with lower lignin content required less delignification to reach higher efficiencies of cellulose conversion during the enzymatic treatment. Conclusion Some of the experimental sugarcane hybrids did have the combined characteristics of high biomass and high sucrose production with low lignin content. Conversion of glucan to glucose by commercial cellulases was increased in the samples with low lignin content. Chemical delignification further increased the cellulose conversion to values of more than 80%. Thus, plants with lower lignin content required less delignification to reach higher efficiencies of cellulose conversion during the enzymatic treatment. PMID:22145819

  7. Composite-Material Tanks with Chemically Resistant Liners

    NASA Technical Reports Server (NTRS)

    DeLay, Thomas K.

    2004-01-01

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

  8. Physical, morphological, and chemical studies of dusts derived from the machining of composite-epoxy materials.

    PubMed

    Boatman, E S; Covert, D; Kalman, D; Luchtel, D; Omenn, G S

    1988-04-01

    This work (in three parts) inquires into whether respirable dusts derived from the machining of six composite-epoxy materials (e.g., aircraft industry) may pose a health risk to the operators. Dust samples representative of a variety of composites and structural components were aerodynamically sized and fractionated. Bulk and fractionated samples were examined by light and electron microscopy and analyzed chemically by thermogravimetry (TGA), gas chromatography (GC) and mass spectrometry (MS). Relative fractions of respirable to total mass of bulk samples were less than 3%; aerodynamic diameters of fractionated particles ranged from 0.8 to 2.0 microns. By microscopy, bulk particles ranged from 7 to 11 microns in diameter, with mean aspect ratios from 4 to 8:1. Mean diameter of fractionated particles was 2.7 microns. By TGA, weight losses were negligible below 250 degrees C and variable but elevated at temperatures up to 860 degrees C. In assays of vapors released at 250 degrees C, GC/MS indicated a variety of compounds in different amounts for each sample. We conclude that under the present machining protocols, dusts at the tool face contained few particles of respirable size with no evidence of splitting of fibers longitudinally and were of a low volatilizable chemical content. Overall, composites were judged to be well cured and thermally stable. PMID:3349976

  9. Materials analysis by ultrasonics: Metals, ceramics, composites

    NASA Technical Reports Server (NTRS)

    Vary, Alex (Editor)

    1987-01-01

    Research results in analytical ultrasonics for characterizing structural materials from metals and ceramics to composites are presented. General topics covered by the conference included: status and advances in analytical ultrasonics for characterizing material microstructures and mechanical properties; status and prospects for ultrasonic measurements of microdamage, degradation, and underlying morphological factors; status and problems in precision measurements of frequency-dependent velocity and attenuation for materials analysis; procedures and requirements for automated, digital signal acquisition, processing, analysis, and interpretation; incentives for analytical ultrasonics in materials research and materials processing, testing, and inspection; and examples of progress in ultrasonics for interrelating microstructure, mechanical properties, and dynamic response.

  10. Propolis from northern California and Oregon: chemical composition, botanical origin, and content of allergens.

    PubMed

    Aliboni, Andrea

    2014-01-01

    Propolis is a beehive product that bees manufacture by mixing their own wax with vegetable resins collected from different species of trees and bushes. The chemical composition of propolis is very variable because it depends on the flora locally available, and specimens from different geographical and climatic areas display unique properties. In this paper, the results of the chemical characterization of some propolis specimens collected in northern California and in Oregon are presented. Their chemical compositions show that all specimens contain resins from poplars of the Tacamahaca section (balsam poplars)--characteristic of the western part of the North American continent. Nevertheless, some of the specimens are of mixed origin because they also contain resins from poplars of the Aigeiros section (cottonwoods)--also present in this part of the world. Propolis causes allergies in sensitive human individuals, which are due to the presence of certain esters. The contents of known propolis allergenic esters--phenylethyl caffeate, 1,1-dimethylallyl caffeate, benzyl cinnamate, and benzyl salicylate--have been investigated in these specimens and found to depend on the botanical origin. PMID:24772818

  11. Catalytic materials prepared by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Vargas-Garcia, J. R.; Goto, T.

    2011-03-01

    In the 1980's appeared the first several scientific papers dealing with chemical vapor deposition (CVD) of nanostructured catalytic materials. Since then, the tremendous increase in the number of related publications indicates the significant importance of CVD for the preparation of catalysts. CVD has the capability to generate various types of catalytically attractive nano-scale structures by modifying the surface properties of massive or even nano-divided substrates. Relatively new CVD processes such as catalytic CVD, fluidized-bed CVD, rotary CVD, two-step CVD and large spot laser CVD allow the formation of nanoparticles, nanotubes, nanofibers, nanocomposites and porous or oriented films. Intensive research is being performed on the production of CNTs and the preparation of supported catalysts by CVD. This paper provides an overview of the relatively new CVD processes involved in the preparation of catalytic materials and some representative examples reported in the open literature.

  12. [Chemical composition, dietary fiber and mineral content of frequently consumed foods in northwest Mexico].

    PubMed

    Haro, M I; Caire, G; Snchez, A; Valencia, M E

    1995-06-01

    Nutrient composition in foods is very important specially in evaluation of nutritional status in populations. In this study the proximate composition, dietary fiber (DF) and mineral content of 15 frequently consumed foods in Northwest Mexico were determined. The procedures used were AOAC (1984) official methods, chemical-enzymatic method for DF and atomic absorption spectrophometry for minerals. Foods were grouped into cereals, legumes, meat and dairy products, fat was the most variable component in all foods (0,41 to 21,1 g/100 g). Fired beans (Phaseolus vulgaris: variedad pinto) had the highest DF content (9,21 g/100g); as is basis). Sodium among the minerales was also highly variable mainly due to the addition of salt during preparation of foods, except in corn tortillas were salt is not added. In contrast wheat flour tortillas had the highest sodium content of the foods analysed. Fresh white cheese had the highest calcium content (563 mg/100g). The meat group had the highest content of Fe and Zn (2,4-5,4 and 4,2-5,4 mg/100 g respectively). This study has provided information with current analytical techniques of important foods in northwest Mexico that will contribute to food composition tables in Latin America. PMID:8729267

  13. Predicting corn digestible and metabolizable energy content from its chemical composition in growing pigs

    PubMed Central

    2014-01-01

    Background The nutrient composition of corn is variable. To prevent unforeseen reductions in growth performance, grading and analytical methods are used to minimize nutrient variability between calculated and analyzed values. This experiment was carried out to define the sources of variation in the energy content of corn and to develop a practical method to accurately estimate the digestible energy (DE) and metabolisable energy (ME) content of individual corn samples for growing pigs. Twenty samples were taken from each of five provinces in China (Jilin, Hebei, Shandong, Liaoning, and Henan) to obtain a range of quality. Results The DE and ME contents of the 100 corn samples were measured in 35.3 ± 1.92 kg growing pigs (six pigs per corn sample). Sixty corn samples were used to build the prediction model; the remaining forty samples were used to test the suitability of these models. The chemical composition of each corn sample was determined, and the results were used to establish prediction equations for DE or ME content from chemical characteristics. The mean DE and ME content of the 100 samples were 4,053 and 3,923 kcal/kg (dry matter basis), respectively. The physical characteristics were determined, as well, and the results indicated that the bulk weight and 1,000-kernel weight were not associated with energy content. The DE and ME values could be accurately predicted from chemical characteristics. The best fit equations were as follows: DE, kcal/kg of DM = 1062.68 + (49.72 × EE) + (0.54 × GE) + (9.11 × starch), with R2 = 0.62, residual standard deviation (RSD) = 48 kcal/kg, and P < 0.01; ME, kcal/kg of dry matter basis (DM) = 671.54 + (0.89 × DE) – (5.57 × NDF) – (191.39 × ash), with R2 = 0.87, RSD = 18 kcal/kg, and P < 0.01. Conclusion This experiment confirms the large variation in the energy content of corn, describes the factors that influence this variation, and presents equations based on chemical measurements that may be used to predict the DE and ME content of individual corn samples. PMID:24521251

  14. Chemical composition, mineral content and amino acid and lipid profiles in bones from various fish species.

    PubMed

    Toppe, Jogeir; Albrektsen, Sissel; Hope, Britt; Aksnes, Anders

    2007-03-01

    The chemical composition, content of minerals and the profiles of amino acids and fatty acids were analyzed in fish bones from eight different species of fish. Fish bones varied significantly in chemical composition. The main difference was lipid content ranging from 23 g/kg in cod (Gadus morhua) to 509 g/kg in mackerel (Scomber scombrus). In general fatty fish species showed higher lipid levels in the bones compared to lean fish species. Similarly, lower levels of protein and ash were observed in bones from fatty fish species. Protein levels differed from 363 g/kg lipid free dry matter (dm) to 568 g/kg lipid free dm with a concomitant inverse difference in ash content. Ash to protein ratio differed from 0.78 to 1.71 with the lowest level in fish that naturally have highest swimming and physical activity. Saithe (Pollachius virens) and salmon (Salmo salar) were found to be significantly different in the levels of lipid, protein and ash, and ash/protein ratio in the bones. Only small differences were observed in the level of amino acids although species specific differences were observed. The levels of Ca and P in lipid free fish bones were about the same in all species analyzed. Fatty acid profile differed in relation to total lipid levels in the fish bones, but some minor differences between fish species were observed. PMID:17208480

  15. Seasonal variation in the chemical composition, antioxidant activity, and total phenolic content of Artemisia absinthium essential oils

    PubMed Central

    Mohammadi, A.; Sani, T. Ahmadzadeh; Ameri, A. A.; Imani, M.; Golmakani, E.; Kamali, H.

    2015-01-01

    Background: The genus Artemisia belonging to the Compositae (Asteraceae) family and many traditional uses from the Artemisia species were reported. Artemisia absinthium is one of the species in this genus and commonly used in the food industry in the preparation of aperitifs, bitters, and spirits. Objective: Evaluation of the effect of different harvesting stages on the composition of essential oil and antioxidant capacity of A. absinthium. Materials and Methods: Essential oils from the aerial parts of A. absinthium, collected in three stages (preflowering, flowering, and after-flowering) from plants grown in the North Khorasan province of Iran were obtained by steam distillation and the chemical composition of the oils was analyzed by gas chromatography-mass spectrometry and antioxidant activity and total phenolic content were determined by 2-diphenyl-1-picrylhydrazyl assay and Folin-Ciocalteu method. Results: Analysis of the isolated oils revealed the presence of 44 compounds, mainly alpha-pinene, sabinene, beta-pinene, alpha-phellandrene, p-cymene and chamazulene. Alpha-phellandrene, and chamazulene were major compounds in preflowering stage, but beta-pinene and alpha-phellandrene were major in flowering and past-flowering stages. Flowering stage had highest yield and after flowering stage had lowest yield. The essential oil of preflowering stage had the highest amount of antioxidant compound (chamazulene). Preflowering stage with highest amount of phenolic compounds had the strongest antioxidant activity with the lowest amount of EC50. Conclusion: This study showed that the harvesting stage had significant effects on chemical composition and antioxidant properties of essential oils, and chamazulene is main compound for antioxidant activity in A. absinthium. PMID:26692746

  16. Transient assembly of active materials fueled by a chemical reaction.

    PubMed

    Boekhoven, Job; Hendriksen, Wouter E; Koper, Ger J M; Eelkema, Rienk; van Esch, Jan H

    2015-09-01

    Fuel-driven self-assembly of actin filaments and microtubules is a key component of cellular organization. Continuous energy supply maintains these transient biomolecular assemblies far from thermodynamic equilibrium, unlike typical synthetic systems that spontaneously assemble at thermodynamic equilibrium. Here, we report the transient self-assembly of synthetic molecules into active materials, driven by the consumption of a chemical fuel. In these materials, reaction rates and fuel levels, instead of equilibrium composition, determine properties such as lifetime, stiffness, and self-regeneration capability. Fibers exhibit strongly nonlinear behavior including stochastic collapse and simultaneous growth and shrinkage, reminiscent of microtubule dynamics. PMID:26339025

  17. Transient assembly of active materials fueled by a chemical reaction

    NASA Astrophysics Data System (ADS)

    Boekhoven, Job; Hendriksen, Wouter E.; Koper, Ger J. M.; Eelkema, Rienk; van Esch, Jan H.

    2015-09-01

    Fuel-driven self-assembly of actin filaments and microtubules is a key component of cellular organization. Continuous energy supply maintains these transient biomolecular assemblies far from thermodynamic equilibrium, unlike typical synthetic systems that spontaneously assemble at thermodynamic equilibrium. Here, we report the transient self-assembly of synthetic molecules into active materials, driven by the consumption of a chemical fuel. In these materials, reaction rates and fuel levels, instead of equilibrium composition, determine properties such as lifetime, stiffness, and self-regeneration capability. Fibers exhibit strongly nonlinear behavior including stochastic collapse and simultaneous growth and shrinkage, reminiscent of microtubule dynamics.

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

    SciTech Connect

    Gemeay, A.H.; Nishiyama, Hiroshi; Kuwabata, Susumu; Yoneyama, Hiroshi

    1995-12-01

    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.

  19. The effect of Zn contents on phase composition, chemical stability and cellular bioactivity in Zn-Ca-Si system ceramics.

    PubMed

    Wu, Chengtie; Ramaswamy, Yogambha; Chang, Jiang; Woods, Joy; Chen, Yiqing; Zreiqat, Hala

    2008-11-01

    Ca-Si system ceramics, in particular CaSiO(3) ceramics, are regarded as potential bioactive bone repair/regeneration material. However, their high dissolution rate limits their biological applications. The aim of this study was to incorporate Zinc (Zn) into the Ca-Si system ceramics to produce part (at 10 and 20% Zn) or complete (at 50% Zn) new crystal phase (hardystonite: Ca(2)ZnSi(2)O(7)) with improved chemical stability and cellular activity. Zn-Ca-Si ceramics with four Zn contents (0, 10, 20, and 50%) were successfully prepared by sintering sol-gel-derived Zn-Ca-Si powder compacts. A new pure crystal phase Ca(2)ZnSi(2)O(7) was formed only when 50% Zn was added. The chemical stability of Zn-Ca-Si ceramics was evaluated by soaking in simulating body fluid (SBF), and the ion release from ceramics and the change in pH values of the SBF were measured. Their ability to form apatite in SBF was determined by analyzing the surface phase composition and morphology of the ceramics using X-ray diffraction and scanning electron microscopy (SEM). Results indicated that, with the increase of Zn contents, the chemical stability of ceramics increased while the apatite-formation ability decreased. The ability of Zn-Ca-Si ceramics to support attachment, proliferation, and differentiation of the human bone osteoblastic-like cells (HOB) was assessed using SEM, MTS, and alkaline phosphate activity assays, respectively. Zn-Ca-Si ceramics supported HOB attachment and their proliferation increased with the increase of Zn content. ALP activity of HOB on Zn-Ca-Si ceramics with 50% Zn (Ca(2)ZnSi(2)O(7)) was the highest among the levels obtained for the four ceramics tested. Taken together, Ca(2)ZnSi(2)O(7) ceramics possessed the best chemical stability and cellular bioactivity in Zn containing Ca-Si ceramics, indicating their potential application in skeletal tissue regeneration. PMID:18464251

  20. Influence of the composition of the initial mixtures on the chemical composition, physicochemical properties and humic-like substances content of composts.

    PubMed

    Silva, Maria Elisabete F; de Lemos, Luís Teixeira; Nunes, Olga C; Cunha-Queda, Ana Cristina

    2014-01-01

    The influence of the proportion of C- and N-rich raw materials (initial C/N ratio) and bulking agent on the chemical functional groups composition, humic-like substances (HS-like) content and physicochemical properties of composts was assessed. To achieve these goals, seven initial mixtures (BA1-6 and C1) of dog food (N-rich raw material) were composted with wheat flour (C-rich raw material). Composts were analyzed in terms of chemical functional groups, physicochemical, maturity and stability parameters. The C-rich raw material favored the formation of oxidized organic matter (OM) during the composting process, as suggested by the variation of the ratios of the peaks intensity of FT-IR spectra, corresponding to a decrease of the polysaccharides and an increase of aromatic and carboxyl-containing compounds. However, although with high proportion of C-rich raw material, mixtures with low initial C/N seems to have favored the accumulation of partially oxidized OM, which may have contributed to high electrical conductivity values in the final composts. Therefore, although favoring the partial transformation of OM into stabilized HS-like, initial mixtures with high proportion of C-rich raw material but with low initial C/N led to unstable composts. On the other hand, as long as a high percentage of bulking agent was used to promote the structure of biomass and consequently improve of the aeration conditions, low initial C/N was not a limiting factor of OM oxidation into extractable stabilized humic-like acids. PMID:24119374

  1. Chemical composition of cottonseed affected by cropping management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cottonseed is a valuable raw material for a range of food, animal feed, and industrial (such as adhesives) products. Chemical composition is one of the critical parameters to evaluate cottonseed's quality and potential end use. However, the information on the impacts of cropping management practices...

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

    PubMed

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

    2012-10-15

    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

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

    NASA Astrophysics Data System (ADS)

    Kollr, Peter; Bir?kov, Zuzana; Vojtek, Vladimr; Fzer, Jn; Bure, Radovan; Fberov, Mria

    2015-08-01

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

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

    PubMed

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

    2014-03-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    SciTech Connect

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

    1999-10-14

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

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    SciTech Connect

    1997-07-25

    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.

  9. Relative toxicity of pyrolysis gases from materials - Effects of chemical composition and test conditions

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Cumming, H. J.

    1978-01-01

    Relative toxicity test data on 270 materials are presented, based on test procedures developed at the University of San Francisco. The effects of chemical composition, using data on 13 types of synthetic polymers and eight types of fabrics, are discussed. Selected materials were evaluated using nine test conditions with the USF method, and using methods developed at the FAA Civil Aeromedical Institute, Douglas Aircraft Company and San Jose State University.

  10. Effects of intra- and inter-laminar resin content on the mechanical properties of toughened composite materials

    NASA Technical Reports Server (NTRS)

    Grande, Dodd H.; Ilcewicz, Larry B.; Avery, William B.; Bascom, Willard D.

    1991-01-01

    Composite materials having multiphase toughened matrix systems and laminate architectures characterized by resin-rich interlaminar layers (RIL) have been the subject of much recent attention. Such materials are likely to find applications in thick compressively loaded structures such as the keel area of commercial aircraft fuselages. The effects of resin content and its interlaminar and intralaminar distribution on mechanical properties were investigated with test and analysis of two carbon-epoxy systems. The RIL was found to reduce the in situ strengthening effect for matrix cracking in laminates. Mode 2 fracture toughness was found to increase with increasing RIL thickness over the range investigated, and Mode 1 interlaminar toughness was negligibly affected. Compressive failure strains were found to increase with increasing resin content for specimens having no damage, holes, and impact damage. Analytical tools for predicting matrix cracking of off-axis plies and damage tolerance in compression after impact (CAI) were successfully applied to materials with RIL.

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

    SciTech Connect

    Setterlund, R.B.

    1996-07-01

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

  12. Damage detection in composite materials by FBGs

    NASA Astrophysics Data System (ADS)

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

    2004-06-01

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

  13. Production of composites by using gliadin as a bonding material

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In our previous papers, a new technology that produces biopolymer composites by particle-bonding was introduced. During the manufacturing process, micrometer-scale raw material was coated with a corn protein, zein, which is then processed to form a rigid material. The coating of raw-material particl...

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

    NASA Astrophysics Data System (ADS)

    Guo, Linfeng; Zhao, Zhimin; Gao, Mingjuan

    2005-10-01

    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 frequency of 1058 Hz. Time-average holographic interferograms were photographed in original, damaged, and repaired samples. By analyzing the three interferograms according to the principles of holographic interferometry, the utility of the light-cured repair material is shown.

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

    PubMed Central

    2013-01-01

    Background This study was conducted to evaluate the apparent metabolizable energy (AME) and true metabolizable energy (TME) contents in 30 sources of corn distillers dried grains with solubles (DDGS) in adult roosters, and establish the prediction equations to estimate the AME and TME value based on its chemical composition and color score. Methods Twenty-eight sources of corn DDGS made from several processing plants in 11 provinces of China and others imported from the United States. DDGS were analyzed for their metabolizable energy (ME) contents, measured for color score and chemical composition (crude protein, crude fat, ash, neutral detergent fiber, acid detergent fiber), to predict the equation of ME in DDGS. A precision-fed rooster assay was used, each DDGS sample was tube fed (50 g) to adult roosters. The experiment was conducted as a randomized incomplete block design with 3 periods. Ninety-five adult roosters were used in each period, with 90 being fed the DDGS samples and 5 being fasted to estimate basal endogenous energy losses. Results Results showed that the AME ranged from 5.93 to 12.19 MJ/kg, TME ranged from 7.28 to 13.54 MJ/kg. Correlations were found between ME and ash content (-0.64, P < 0.01) and between ME and yellowness score (0.39, P < 0.05) of the DDGS samples. Furthermore, the best-fit regression equation for AME content of DDGS based on chemical composition and color score was AME = 6.57111 + 0.51475 GE - 0.10003 NDF + 0.13380 ADF + 0.07057 fat - 0.57029 ash - 0.02437 L (R2 = 0.70). The best-fit regression equation for TME content of DDGS was TME = 7.92283 + 0.51475 GE - 0.10003 NDF + 0.13380 ADF + 0.07057 fat - 0.57029 ash - 0.02437 L (R2 = 0.70). Conclusions This experiment suggested that measuring the chemical composition and color score of a corn DDGS sample may provide a quality parameter for identifying corn DDGS sources energy digestibility and metabolizable energy content. PMID:24066830

  16. Mechanical behaviour of composite materials made by resin film infusion

    NASA Astrophysics Data System (ADS)

    Barile, C.; Casavola, C.; Pappalettere, C.; Tursi, F.

    2010-06-01

    Innovative composite materials are frequently used in designing aerospace, naval and automotive components. In the typical structure of composites, multiple layers are stacked together with a particular sequence in order to give specific mechanical properties. Layers are organized with different angles, different sequences and different technological process to obtain a new and innovative material. From the standpoint of engineering designer it is useful to consider the single layer of composite as macroscopically homogeneous material. However, composites are non homogeneous bodies. Moreover, layers are not often perfectly bonded together and delamination often occurs. Other violations of lamination theory hypotheses, such as plane stress and thin material, are not unusual and in many cases the transverse shear flexibility and the thickness-normal stiffness should be considered. Therefore the real behaviour of composite materials is quite different from the predictions coming from the traditional lamination theory. Due to the increasing structural performance required to innovative composites, the knowledge of the mechanical properties for different loading cases is a fundamental source of concern. Experimental characterization of materials and structures in different environmental conditions is extremely important to understand the mechanical behaviour of these new materials. The purpose of the present work is to characterize a composite material developed for aerospace applications and produced by means of the resin film infusion process (RFI). Different tests have been carried out: tensile, open-hole and filled-hole tensile, compressive, openhole and filled-hole compressive. The experimental campaign has the aim to define mechanical characteristics of this RFI composite material in different conditions: environmental temperature, Hot/Wet and Cold.

  17. Composite material

    DOEpatents

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O'Neill, Hugh M.

    2012-02-07

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

  18. Structure and chemical composition of the dentin-enamel junction analyzed by Confocal Raman Microscopy

    NASA Astrophysics Data System (ADS)

    Desoutter, A.; Salehi, H.; Slimani, A.; Marquet, P.; Jacquot, B.; Tassery, H.; Cuisinier, F. J. G.

    2014-02-01

    The structure and chemical composition of the human dentin-enamel junction (DEJ) was studied using confocal Raman microscopy - a chemical imaging technique. Slices of non-fixed, sound teeth were prepared with an Isomet diamond saw and scanned with Witec Alpha300R system. The combination of different characteristics peaks of phosphate, carbonate and organic matrix (respectively 960, 1072 and 1545 cm-1), generates images representing the chemical composition of the DEJ area. Images are also calculated using peak ratios enabling precise determination of the chemical composition across the DEJ. Then, with two characterized peaks, different pictures are calculated to show the ratio of two components. The images of the spatial distribution of mineral phosphate (960cm-1) to organic matrix (1545 cm-1) ratios, mineral carbonates (1072cm-1) to mineral phosphate ratios; and mineral carbonates to organic matrix ratios were reconstructed. Cross sectional and calculated graphic profile show the variations of the different chemical component ratios through the enamel and the dentin. Phosphate to organic ratio shows an accumulation of organic material under the enamel surface. The cross sectional profile of these pictures shows a high phosphate content compared to enamel in the vicinity of the DEJ. The Confocal Raman imaging technique can be used to further provide full chemical imaging of tooth, particularly of the whole DEJ and to study enamel and dentin decay.

  19. Chemical Fractionation in Chondrites by Aerodynamic Sorting of Chondritic Materials

    NASA Astrophysics Data System (ADS)

    Scott, E. R. D.; Haack, H.

    1993-07-01

    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 of all chondritic ingredients and were therefore a major source of chemical differences between asteroids and perhaps planets [4]. For chondrites that were derived from the same batch of chondritic ingredients, e.g., ordinary chondrites, aerodynamic sorting may account for all chemical differences [5]. Matrix Material: Matrix material accretes into planetesimals largely in the form of rims on all particles rather than as individual dust grains [6,7]. Aerodynamic sorting of particles does not cause significant chemical variation in bulk matrix abundance or composition because rim composition is not correlated with particle composition [6,7], and rim thickness apparently correlates with particle radius [7]. Metal-Troilite Spherules: There are at least two metal-troilite components: poorly characterized spherules that are probably ejected during chondrule formation and fine-grained material associated with matrix rims. Skinner and Leenhouts [2] suggest that aerodynamic sorting of the spherules was a potent metal-silicate fractionation process. Our preliminary data for metal-troilite spherules in Lance (CO3) support their model. Spherules and chondrules are closer in size than in the CR chondrite they studied, but this may result from the very much higher troilite abundance in CO chondrites, which produced a smaller density difference between chondrules and spherules. But we cannot exclude the possibility that the size distribution of metallic spherules was controlled by that of the chondrules from which they were ejected and not by aerodynamic sorting of spherules. Matrix rims on spherules preclude the possibility that the spherules were released from chondrules during parent body impacts. Refractory Inclusions: The similarity in the order of chondrule and CAI sizes suggests a common size sorting process. Chondrules decrease in mean size in the order CV (1.0 mm) > CM (0.3 mm) > CO (0.15 mm) > ALH85085 (0.02 mm) [8]. Refractory inclusions decrease in size in the order CV (commonly >1 cm) > CO > CM (<1 mm) > ALH85085 (0.03 mm) [8,9]. Although many chondrules and CAIs in ALH85085 are broken, mean sizes were not much bigger originally as the grain sizes of fragments are comparable to those of complete objects [6]. Size sorting must postdate CAI formation as these size relationships hold for all kinds of CAI that formed in very different ways. Density differences cannot account for the apparently larger mean size of CAIs relative to chondrules in CV3 chondrites. Model: We suggest that a common aerodynamic sorting process may have affected all ingredients during their fall toward the proto-Sun through nebula gas. This sorting probably occurred after chondrule formation and rim acquisition in a turbulent environment [7] and ended when planetesimal accretion halted inward motion. Intermittent turbulence may have cleared the midplane of chondritic materials to allow episodic accretion of distinctly different batches of material. This model and runaway accretion of planetesimals accounts for the correlation of chondrule size with metamorphic type in CO3 chondrites [8] and provides a mechanism for understanding chemical and isotopic variations within asteroids such as the ureilite parent body. References: [1] Rubin A. E. and Keil K. (1984) Meteoritics, 19, 135-143. [2] Skinner W. R. and Leenhouts J. M. (1993) LPSC XXIV, 1315-1316. [3] Clayton R. N. et al. (1991) GCA, 55, 2317-2337. [4] Scott E. R. D. and Newsom H. E. (1989) Z. Naturforsch., 44a, 924-934. [5] Haack H. and Scott E. R. D. (1993), this volume. [6] Scott E. R. D. et al. (1984) GCA, 48, 1741-1757. [7] Metzler K. et al. (1992) GCA, 56, 2873-2987. [8] Meteorites and The Early Solar System (J. F. Kerridge and M. S. Matthews, eds.), chapters 9.1 and 10.3. [9] Grossman J. N. et al. EPSL, 91, 33-54.

  20. (210)Pb content in natural gas pipeline residues ("black-powder") and its correlation with the chemical composition.

    PubMed

    Godoy, Jos Marcus; Carvalho, Franciane; Cordilha, Aloisio; Matta, Luiz Ernesto; Godoy, Maria Luiza

    2005-01-01

    The present work was carried out to assess the (210)Pb content in "black-powder" found in pigging operations on gas pipelines in Brazil, in particular, on the Campos Basin gas pipeline. Additionally, the chemical composition of such deposits was determined and an eventual correlation with (210)Pb concentration evaluated. Typical "black-powder" generated in the natural gas pipeline from Campos Basin oilfield contains mainly iron oxide ( approximately 81%) and residual organic matter ( approximately 9%). The (210)Pb content ranges from 4.9 to 0.04k Bqkg(-1) and seems to be inversely correlated with the distance to the platforms. On the other hand, (226)Ra concentration is higher on the pipeline branch between the platform and the onshore installations. (228)Ra was only observed in few samples, in particular, in the samples with the highest (226)Ra content. PMID:15885858

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

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

  2. Mesoporous carbon/zirconia composites: a potential route to chemically functionalized electrically-conductive mesoporous materials.

    PubMed

    Oh, Jung-Min; Kumbhar, Amar S; Geiculescu, Olt; Creager, Stephen E

    2012-02-14

    Mesoporous nanocomposite materials in which nanoscale zirconia (ZrO(2)) particles are embedded in the carbon skeleton of a templated mesoporous carbon matrix were prepared, and the embedded zirconia sites were used to accomplish chemical functionalization of the interior surfaces of mesopores. These nanocomposite materials offer a unique combination of high porosity (e.g., ?84% void space), electrical conductivity, and surface tailorability. The ZrO(2)/carbon nanocomposites were characterized by thermogravimetric analysis, nitrogen-adsorption porosimetry, helium pychnometry, powder X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Comparison was made with templated mesoporous carbon samples prepared without addition of ZrO(2). Treatment of the nanocomposites with phenylphosphonic acid was undertaken and shown to result in robust binding of the phosphonic acid to the surface of ZrO(2) particles. Incorporation of nanoscale ZrO(2) surfaces in the mesoporous composite skeleton offers unique promise as a means for anchoring organophosphonates inside of pores through formation of robust covalent Zr-O-P bonds. PMID:22248432

  3. Aqueous fluid composition in CI chondritic materials: Chemical equilibrium assessments in closed systems

    NASA Astrophysics Data System (ADS)

    Zolotov, Mikhail Yu.

    2012-08-01

    Solids of nearly solar composition have interacted with aqueous fluids on carbonaceous asteroids, icy moons, and trans-neptunian objects. These processes altered mineralogy of accreted materials together with compositions of aqueous and gaseous phases. We evaluated chemistry of aqueous solutions coexisted with CI-type chondritic solids through calculations of chemical equilibria in closed water-rock-gas systems at different compositions of initial fluids, water/rock mass ratios (0.1-1000), temperatures (<350 C), and pressures (<2 kbars). The calculations show that fluid compositions are mainly affected by solubilities of solids, the speciation of chlorine in initial water-rock mixtures, and the occurrence of Na-bearing secondary minerals such as saponite. The major species in modeled alkaline solutions are Na+, Cl-, CO32-,HCO3-, K+, OH-, H2, and CO2. Aqueous species of Mg, Fe, Ca, Mn, Al, Ni, Cr, S, and P are not abundant in these fluids owing to low solubility of corresponding solids. Typical NaCl type alkaline fluids coexist with saponite-bearing mineralogy that usually present in aqueously altered chondrites. A common occurrence of these fluids is consistent with the composition of grains emitted from Enceladus. Na-rich fluids with abundant CO32-,HCO3-, and OH- anions coexist with secondary mineralogy depleted in Na. The Na2CO3 and NaHCO3 type fluids could form via accretion of cometary ices. NaOH type fluids form in reduced environments and may locally occur on parent bodies of CR carbonaceous chondrites. Supposed melting of accreted HCl-bearing ices leads to early acidic fluids enriched in Mg, Fe and other metals, consistent with signs of low-pH alteration in chondrites. Neutralization of these solutions leads to alkaline Na-rich fluids. Sulfate species have negligible concentrations in closed systems, which remain reduced, especially at elevated pressures created by forming H2 gas. Hydrogen, CO2, and H2O dominate in the gaseous phase, though the abundance of methane cannot be fairly estimated.

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

    DOEpatents

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

    1990-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Ikeda, Tsutomu; Yamaguchi, Atsushi; Matsuishi, Takashi

    2006-11-01

    Condition factor index [CFI=1000DW/(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 (500-1000 m), upper-bathypelagic (1000-2000 m), lower-bathypelagic (2000-3000 m) and abyssopelagic (3000-5000 m) zones of the western subarctic Pacific. Resultant data were grouped into these four sampling zones, four developmental stage/sex categories (C4, C5 and C6 females and males), three feeding types (carnivore, detritivore and suspension feeder), or two reaction speed groups by the presence/absence of myelinated sheath enveloping axons (fast and slow reacting species). Zone-structured data showed the overall ranges were 3.8-4.6 mm for PL, 1.6-2.6 mg for DW, 21.4-25.0 for CFI, 75.0-78.6% of wet weight (WW) for water, 51.3-53.7% of DW for C, 7.7-8.8% of DW for N, 6.2-7.0 (by weight) for C/N, 6.9-9.6% of DW for ash and 25.3-27.4 J mg -1 DW for energy. Among these components, N and ash exhibited significant between-zone differences characterized by gradual decrease downward for the former, and only the upper-bathypelagic zone>abyssopelagic zone for the latter. Stage/sex-structured data showed no significant differences among them, but energy content of C5 was higher than that of C6 females. From the analyses of feeding type-structured data, carnivores were shown to have lower water, N, ash, but higher C, C/N and energy contents than suspension feeders do. Reaction speed-structured data indicated that slow-reacting species have significantly higher water but lower CFI, C, N and energy contents than fast-reacting species. Designating these grouping criteria, PL and DW as independent variables, the attributes of these variables to the CFI, chemical composition or energy contents were evaluated by stepwise-multiple regression analysis, showing the most pronounced effect of suspension-feeder, followed by the presence of myelinated sheath, DW, C6 females and the abyssopelagic zone. Further analysis of zone-structured data, by adding epipelagic copepod data from identical thermal habitats (Arctic/Antarctic waters), revealed a more marked decline in N content from the epipelagic zone to the abyssopelagic zone, accompanied by an increase in C/N ratios downward. The decline in N (=protein or muscle) contents with depth cannot be explained by the "visual interactions" hypotheses being proposed for the metabolism of pelagic visual predators, but is consistent with the "predation-mediated selection" hypothesis for the metabolism of pelagic copepods.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  7. Optimum conditions for composites fiber coating by chemical vapor infiltration

    SciTech Connect

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

    1997-04-01

    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.

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

    SciTech Connect

    Vukasinovic-Pesic, V.; Rajakovic, L.J.

    2009-07-01

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

  9. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

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

  10. Integration of calcium and chemical looping combustion using composite CaO/CuO-based materials.

    PubMed

    Manovic, Vasilije; Anthony, Edward J

    2011-12-15

    Calcium looping cycles (CaL) and chemical looping combustion (CLC) are two new, developing technologies for reduction of CO(2) emissions from plants using fossil fuels for energy production, which are being intensively examined. Calcium looping is a two-stage process, which includes oxy-fuel combustion for sorbent regeneration, i.e., generation of a concentrated CO(2) stream. This paper discuss the development of composite materials which can use copper(II)-oxide (CuO) as an oxygen carrier to provide oxygen for the sorbent regeneration stage of calcium looping. In other words, the work presented here involves integration of calcium looping and chemical looping into a new class of postcombustion CO(2) capture processes designated as integrated CaL and CLC (CaL-CLC or Ca-Cu looping cycles) using composite pellets containing lime (CaO) and CuO together with the addition of calcium aluminate cement as a binder. Their activity was tested in a thermogravimetric analyzer (TGA) during calcination/reduction/oxidation/carbonation cycles. The calcination/reduction typically was performed in methane (CH(4)), and the oxidation/carbonation stage was carried out using a gas mixture containing both CO(2) and O(2). It was confirmed that the material synthesized is suitable for the proposed cycles; with the very favorable finding that reduction/oxidation of the oxygen carrier is complete. Various schemes for the Ca-Cu looping process have been explored here that would be compatible with these new composite materials, along with some different possibilities for flow directions among carbonator, calciner, and air reactor. PMID:22022778

  11. Characterisation of chemical composition and energy content of green waste and municipal solid waste from Greater Brisbane, Australia.

    PubMed

    Hla, San Shwe; Roberts, Daniel

    2015-07-01

    The development and deployment of thermochemical waste-to-energy systems requires an understanding of the fundamental characteristics of waste streams. Despite Australia's growing interest in gasification of waste streams, no data are available on their thermochemical properties. This work presents, for the first time, a characterisation of green waste and municipal solid waste in terms of chemistry and energy content. The study took place in Brisbane, the capital city of Queensland. The municipal solid waste was hand-sorted and classified into ten groups, including non-combustibles. The chemical properties of the combustible portion of municipal solid waste were measured directly and compared with calculations made based on their weight ratios in the overall municipal solid waste. The results obtained from both methods were in good agreement. The moisture content of green waste ranged from 29% to 46%. This variability - and the tendency for soil material to contaminate the samples - was the main contributor to the variation of samples' energy content, which ranged between 7.8 and 10.7MJ/kg. The total moisture content of food wastes and garden wastes was as high as 70% and 60%, respectively, while the total moisture content of non-packaging plastics was as low as 2.2%. The overall energy content (lower heating value on a wet basis, LHVwb) of the municipal solid waste was 7.9MJ/kg, which is well above the World Bank-recommended value for utilisation in thermochemical conversion processes. PMID:25882791

  12. Variation in Content Coverage by Classroom Composition: An Analysis of Advanced Math Course Content

    ERIC Educational Resources Information Center

    Covay, Elizabeth

    2011-01-01

    Everyone knows that there is racial inequality in achievement returns from advanced math; however, they do not know why black students and white students taking the same level of math courses are not leaving with the same or comparable skill levels. To find out, the author examines variation in course coverage by the racial composition of the

  13. The Chemical Nature of the Fiber/resin Interface in Composite Materials

    NASA Technical Reports Server (NTRS)

    Diefendorf, R. J.

    1984-01-01

    Carbon fiber/epoxy resin composites are considered. The nature of the fiber structure and the interaction that occurs at the interface between fiber and matrix are emphasized. Composite toughness can be improved by increased axial tensile and compressive strengths in the fibers. The structure of carbon fibers indicates that the fiber itself can fail transversely, and different transverse microstructures could provide better transverse strengths. The higher surface roughness of lower modulus and surface-treated carbon fibers provides better mechanical interlocking between the fiber and matrix. The chemical nature of the fiber surface was determined, and adsorption of species on this surface can be used to promote wetting and adhesion. Finally, the magnitude of the interfacial bond strength should be controlled such that a range of composites can be made with properties varying from relatively brittle and high interlaminar shear strength to tougher but lower interlaminar shear strength.

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

    PubMed Central

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

    2012-01-01

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

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

    PubMed

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

    2012-01-01

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

  16. Studies of heterogeneous samples and material composition by fluorescence XAFS

    NASA Astrophysics Data System (ADS)

    Tannazi, Firouzeh

    X-ray Absorption Fine Structure (XAFS) Spectroscopy has proven to be an important tool for studying the composition and structure of materials. One benefit of XAFS is that it can be applied to a wide variety of systems, including complex real-world samples such as those found in biology and the environment. Determination of the chemical speciation of toxic elements in the environment currently is an active area of research. This dissertation describes my application of XAFS to chemical speciation in environmental soil samples as well as synthetic samples. In situ experimental XAFS measurements of metal speciation in soil core samples were made and the results were correlated with speciation results from chemical extraction. Several numerical approaches were implemented and tested. A novel approach to determining speciation by a Linear Programming algorithm was developed and found to be the most successful method for dilute samples of small particle size, i.e. in the linear regime. However, discrepancies between the in situ speciation results and other methods led to a fundamental investigation of x-ray transport in heterogeneous samples in which the observed fluorescence spectrum no longer is a linear combination of the spectra of the constituents. Useful theoretical models of x-ray propagation through heterogeneous media were found in older x-ray spectrometry literature, corrected, adapted for the first time to XAFS spectra. A Monte Carlo method was developed to calculate the effect on spectra of the shape, size, and orientation of particles of arbitrary convex shape, and the results are parameterized so that the loss factors can be easily calculated. Combining these models permits one to compute the fluorescence from arbitrary randomly heterogeneous particulate samples. This work demonstrates that the particle size distribution and the solid packing fraction have an important effect on the resulting spectra, which, if neglected, can introduce significant errors in speciation results and structure determination by XAFS, particularly for in situ studies. The relevance of these effects seems to have escaped the attention of most researchers in the field. The computational methods and results presented in this dissertation allow experimenters to estimate the impact of heterogeneity effects on their measurements.

  17. /Al-4Cu Composite Material Produced by Squeeze Casting Method

    NASA Astrophysics Data System (ADS)

    Ficici, Ferit

    2014-05-01

    The wear behavior of a weight fraction of particles with up to 30 wt.% in situ AlB2 flakes reinforced in Al-4Cu matrix alloy composites and fabricated by a squeeze casting method was investigated in a pin-on-disk abrasion test instrument against different SiC abrasives at room conditions. Wear tests were performed under the load of 10 N against SiC abrasive papers of 80, 100, and 120 mesh grits. The effects of sliding speed, AlB2 flake content, and abrasive grit sizes on the abrasive wear properties of the matrix alloy and composites have been evaluated. The main wear mechanisms were identified using an optical microscope. The results showed that in situ AlB2 flake reinforcement improved the abrasion resistance against all the abrasives used, and the abrasive wear resistance decreased with an increase in the sliding speed and the abrasive grit size. The wear resistances of the composites were considerably bigger than those of the matrix alloy and increased with increases in in situ AlB2 flake contents.

  18. Radon diffusion coefficients in 360 waterproof materials of different chemical composition.

    PubMed

    Jiránek, M; Kotrbatá, M

    2011-05-01

    This paper summarises the results of radon diffusion coefficient measurements in 360 common waterproof materials available throughout Europe. The materials were grouped into 26 categories according to their chemical composition. It was found that the diffusion coefficients of materials used for protecting houses against radon vary within eight orders from 10(-15) to 10(-8) m(2) s(-1). The lowest values were obtained for bitumen membranes with an Al carrier film and for ethylene vinyl acetate membranes. The highest radon diffusion coefficient values were discovered for sodium bentonite membranes, rubber membranes made of ethylene propylene diene monomer and polymer cement coatings. The radon diffusion coefficients for waterproofings widely used for protecting houses, i.e. flexible polyvinyl chloride, high-, low-density polyethylene, polypropylene and bitumen membranes, vary in the range from 3 × 10(-12) to 3 × 10(-11) m(2) s(-1). Tests were performed which confirmed that the radon diffusion coefficient is also an effective tool for verifying the air-tightness of joints. PMID:21450700

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

    PubMed

    Edris, Amr E

    2011-03-01

    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 100C 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

  20. Composite material dosimeters

    DOEpatents

    Miller, Steven D. (Richland, WA)

    1996-01-01

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

  1. Chemical composition, antioxidant capacity and content of phenolic compounds in meals collected in hospitals in Bolivia and Sweden.

    PubMed

    Tejeda, L; Dębiec, M; Nilsson, L; Peñarrieta, J M; Alvarado, J A

    2012-01-01

    The objective of this study was to evaluate the proximal composition, as well as Total Antioxidant Capacity (TAC) and Total Phenols (TPH) in meals that represent a complex food matrix, from different hospitals in Bolivia and Sweden. Protein, fat, ash, dietary fiber and carbohydrate contents were measured in 29 samples: 20 from two Bolivian hospitals and 9 from the university hospital in Lund, Sweden. The antioxidant capacity was measured by three spectrophotometric methods: the ferric reducing antioxidant power (FRAP) method, the 2, 2'- azinobis-3-ethylbenzotiazoline-6-sulfonic acid (ABTS) method and Total Phenolic Compounds (TPH) using the Folin-Ciocalteu reagent. The results show that fat, protein, carbohydrate and dietary fiber in Bolivian and Swedish hospital meals are following internationally established recommendations. Regarding the main courses, TPH contents in both countries were in the same range. However, TAC and dietary fiber content were higher in Swedish meals than in Bolivian meals and the TAC was far lower, in both cases, in comparison with the value obtained from individual food items reported from literature. The results show that antioxidant levels can be easily overestimated by considering only individual uncooked ingredients. An interesting consideration is, the fiber content in the meals, which can be an important source of antioxidants and non-extractable phenolic compounds. PMID:23165536

  2. Fatigue Crack Measurement in Composite Materials by Ultrasonic Methods

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  3. What controls the composition of weathered materials transported by large river systems (Invited)

    NASA Astrophysics Data System (ADS)

    Gaillardet, J.; Bouchez, J.; France-Lanord, C.; Maurice, L.

    2009-12-01

    The critical zone of the Earth is a complex reactor where physical, biological and chemical processes interact to transform the crustal rocks into weathered materials. The river system is selectively transporting materials according to the intensity of physical erosion and the transport capacity of the river system it self. The main advantage of rivers is that they integrate the diversity of processes playing a role in the critical zone. However, using rivers to establish the fluxes of weathered material produced at the atmosphere-hydrosphere-geosphere interface requires a better understanding of the role of parameters such as the nature of the bedrock, the chemical weathering regimes, the physical conditions of transport and their interplay. Although all materials produced by chemical weathering should be exported out of the fluvial system, we are far from understanding the timescales and processes that operate between the top soil and the sea. We will present new results on the chemical and isotopic composition of suspended sediments and bedload sediments from the Amazon river system. Suspended sediments have been sampled along cross sections of the Amazon, Madeira and Solimoes rivers, at different depth in order to cover the whole range of physical conditions of transport. A considerable variability of composition is observed that clearly shows that surface suspended sediments, usually sampled, only poorly represent the chemical composition of the weathered material transported by the river. New estimates of chemical fluxes of material delivered to the ocean by the first largest river of the world can therefore be estimated. The results show that the composition of river sediments is not only controlled by present day chemical weathering conditions in the drainage basin, but also by the chemical history of the bedrock, and thus crustal recycling processes. There is a good correlation between grain size and the chemical composition of the Amazon river suspended sediments and this correlation can be extended to other large river systems such as the Ganges and Brahmaputra system. This new approach of considering the whole spectrum of grain size transported in river systems leads to revisit the classical notions of weathering-limited and transport-limited regimes of erosion.

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

    PubMed

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

    2014-01-01

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

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

    SciTech Connect

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

    2011-01-17

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    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.

  7. Interplanetary dust particles, quantitative material properties and bulk chemical composition of meteors

    NASA Astrophysics Data System (ADS)

    Rietmeijer, F. J.

    Meteors fill the gap between interplanetary dust particles (IDPs) and meteorites that are collected for laboratory analyses. When interacting with the atmosphere meteors leave potentially extractable information on mass (size), density, internal texture (massive or aggregates), sizes of building blocks (meteor fragmentation behavior), and bulk composition of "coherent entities" (light curves). Most comet nuclei and many undifferentiated asteroids are rubble piles that could potentially produce meteors ranging from several hundreds of meter-sized pre-protoplanets, boulders (several meters to sub-meter-size), cm/mm-size pebbles and dust. The hypothesis of hierarchical dust accretion describes the mineralogical variations and chemical changes of heterogeneous, micron to mm-sized meteors and constituent grain size. The initially accreting dusts had a non-chondritic composition. Dust in "dirty-ice" or "icy-dirt" was latest-accreted nebular dust once most of the evolved dust had accreted into pre-protoplanets where it was subjected to aqueous, thermal, or both, modification. The hypothesis can no longer be traced when dust +/- ice aggregates composition but will be texturally and mineralogically heterogeneous unless parent body processes had modified or erased initial heterogeneity when forming new, secondary, minerals that would decrease bulk porosity while increasing material strength. It is generally assumed that such modifications will require a sustained thermal regime but the metastable nature of sub-millimeter grains would allow modification well below equilibrium temperatures. After modification or lithification of accretionary-evolved pre-proto-planets, the resulting rubble pile will preserve a fractal nature from the largest down to the smallest dust aggregates. Its mm-sized and larger meteors would range from Si-rich proto-CI aggregates to fully-hydrated CI, possible also CM, boulders. Mapping the properties listed at the top for individual "dust and small boulder" meteors from comet nuclei in different meteor streams might produce a picture of accretion and (pre)protoplanetary dust modification from these near-surface source sample to asses differences between and among active, dormant and extinct rubble piles from the Oort cloud, KBOs and NEAs, even on-orbit meteoroid modification. Ironically the smallest, thus faintest, meteors would be of greatest interest. Yet, larger meteoroids will remain the only option to learn the nature of the pebbles and boulders that could be CI/CM like, or much-less modified precursor materials.

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

    SciTech Connect

    Lee, W.Y.

    1996-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  10. Contents and composition of organic matter in subsurface soils affected by land use and soil mineralogy

    NASA Astrophysics Data System (ADS)

    Ellerbrock, Ruth H.; Kaiser, Michael

    2010-05-01

    Land use and mineralogy affect the ability of surface as well as subsurface soils to sequester organic carbon and their contribution to mitigate the greenhouse effect. This study aimed to investigate the long-term impact of land use (i.e., arable and forest) and soil mineralogy on contents and composition of soil organic matter (SOM) from subsurface soils. Seven soils different in mineralogy (Albic and Haplic Luvisol, Colluvic and Haplic Regosol, Haplic and Vertic Cambisol, Haplic Stagnosol) were selected within Germany. Soil samples were taken from forest and adjacent arable sites. First, particulate and water soluble organic matter were separated from the subsurface soil samples. From the remaining solid residues the OM(PY) fractions were separated, analyzed for its OC content (OCPY) and characterized by FTIR spectroscopy. For the arable subsurface soils multiple regression analyses indicate significant positive relationships between the soil organic carbon contents and the contents of i) exchangeable Ca and oxalate soluble Fe, and Alox contents. Further for the neutral arable subsurface soils the contents OCPY weighted by its C=O contents were found to be related to the contents of Ca indicating interactions between OM(PY) and Ca cations. For the forest subsurface soils (pH <5) the OCPY contents were positively related with the contents of Na-pyrophosphate soluble Fe and Al. For the acidic forest subsurface soils such findings indicate interactions between OM(PY) and Fe3+ and Al3+ cations. The effects of land use and soil mineralogy on contents and composition of SOM and OM(PY) will be discussed.

  11. HDPE-HA composites synthetized by in situ polymerization with different filler content

    NASA Astrophysics Data System (ADS)

    Hermán, V.; Karam, A.; Albano, C.; Romero, K.; González, G.

    2012-07-01

    In Situ ethylene polymerization was used to synthesize high density polyethylene - hydroxyapatite (HDPE-HA) composites, employing Cp2ZrCl2/MAO as catalytic system. A good dispersion of HA into the HDPE matrix was obtained when the following synthesis conditions were combined: high stirring velocities (2000 rpm), low quantities of solvent (100 mL), and 10 °C. Under these conditions different filler content was used to synthetized HDPE-HA composites. An interaction between HA and HDPE was obtained by FTIR. On the other hand, thermal analysis indicated that no significant differences were observed between HDPE and the composites.

  12. Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse

    USGS Publications Warehouse

    Plumlee, Geoffrey S.; Hageman, Philip L.; Lamothe, Paul J.; Ziegler, Thomas L.; Meeker, Gregory P.; Theodorakos, Peter M.; Brownfield, Isabelle; Adams, Monique G.; Swayze, Gregg A.; Hoefen, Todd M.; Taggart, Joseph E.; Clark, Roger N.; Wilson, S.; Sutley, Stephen J.

    2009-01-01

    Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions with rain water or water used in street washing and fire fighting. Chemical leach tests using deionized water as the extraction fluid show the dust samples can be quite alkaline, due primarily to reactions with calcium hydroxide in concrete particles. Calcium and sulfate are the most soluble components in the dust, but many other elements are also readily leached, including metals such as Al, Sb, Mo Cr, Cu, and Zn. Indoor dust samples produce leachates with higher pH, alkalinity, and dissolved solids than outdoor dust samples, suggesting most outdoor dust had reacted with water and atmospheric carbon dioxide prior to sample collection. Leach tests using simulated lung fluids as the extracting fluid suggest that the dust might also be quite reactive in fluids lining the respiratory tract, resulting in dissolution of some particles and possible precipitation of new phases such as phosphates, carbonates, and silicates. Results of these chemical characterization studies can be used by health scientists as they continue to track and interpret health effects resulting from the short-term exposure to the initial dust cloud and the longer-term exposure to dusts resuspended during cleanup.

  13. Regulating continent growth and composition by chemical weathering

    PubMed Central

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

    2008-01-01

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

  14. Chemical Fingerprinting of Materials Developed Due to Environmental Issues

    NASA Technical Reports Server (NTRS)

    Smith, Doris A.; McCool, A. (Technical Monitor)

    2000-01-01

    Instrumental chemical analysis methods are developed and used to chemically fingerprint new and modified External Tank materials made necessary by changing environmental requirements. Chemical fingerprinting can detect and diagnose variations in material composition. To chemically characterize each material, fingerprint methods are selected from an extensive toolbox based on the material's chemistry and the ability of the specific methods to detect the material's critical ingredients. Fingerprint methods have been developed for a variety of materials including Thermal Protection System foams, adhesives, primers, and composites.

  15. [Chemical composition, amino acid content and nutritive value of the protein of the annatto seed (Bixa orellana, L.)].

    PubMed

    Bressani, R; Porta-Espaa de Barnen, F; Braham, J E; Elas, L G; Gmez-Brenes, R

    1983-06-01

    On several occasions, many Latin American countries have shown interest in the economic potential of industrializing the exploitation of the pigment in Annatto seed (Bixa orellana, L) used as a natural coloring agent in the food industry. Production of the pigment leaves the seed as a by-product, which once characterized chemically and nutritionally, could contribute to a more profitable exploitation of Annatto seed. The main objective of the present study was to obtain information in regard to this matter. The results of chemical analyses of the seed showed a relatively high amount of protein, which fluctuated between 13 and 17%. Crude fiber levels were also high, about 16%; however, more than 50% of this fiber can be eliminated through sifting of the seed flour. This operation also increases protein content. Annatto seeds have a high phosphorus and a low calcium content. Its protein contains adequate levels of tryptophan and lysine, but is low in methionine, isoleucine, leucine, phenylalanine and threonine. The protein quality of Annatto seed flour was about 65% that of casein, which was used as reference protein. Partly responsible for this low biological value are the amino acid deficiencies, mainly that of methionine, and the low digestibility of the protein. The latter was 57% as compared to 94% for casein, a finding which can be attributed to the crude fiber content of Annatto seed flour, since partial elimination of the fiber resulted in an increase in digestibility up to a value of 65%. In order to utilize more effectively this potential feedstuff in combination with other feeds, further studies should confirm the amino acid deficiencies and digestibility of the Annatto seed protein. PMID:6673674

  16. Anisotropic compositional expansion in elastoplastic materials and corresponding chemical potential: Large-strain formulation and application to amorphous lithiated silicon

    NASA Astrophysics Data System (ADS)

    Levitas, Valery I.; Attariani, Hamed

    2014-09-01

    A general large-strain thermodynamic approach with anisotropic (tensorial) compositional expansion/contraction in elastoplastic material under stress tensor is developed. The dissipation rate due to compositional expansion/contraction is introduced. Adapting and utilizing a previously formulated postulate of realizability, we derived a simple equation for the deviatoric part of the compositional deformation rate. This leads to a nontrivial generalization of the concept and expression for the chemical potential. It receives a contribution from deviatoric stresses, which leads to an increase in the driving force for both the compositional expansion and contraction and to some new phenomena. Our model provides a remarkable description of the known experimental and atomistic simulation data on the biaxial stress evolution during lithiation-delithiation of LixSi on a rigid substrate with just one constant kinetic coefficient. In contrast to known approaches, it does not involve plasticity, because the yield strength is higher than the stresses generated during lithiation-delithiation. This allowed us to suggest a method for reduction in internal stresses by cyclic change in Li concentration with a small amplitude, and our simulations were in qualitative agreement with known experiments. The coupled diffusion and mechanical model was applied to lithiation and delithiation of thin-film, solid, and hollow spherical nanoparticles. The importance of the contribution of the deviatoric stress on the diffusion is demonstrated.

  17. Major element chemical compositions of chondrules in unequilibrated chondrites

    NASA Technical Reports Server (NTRS)

    Ikeda, Y.

    1984-01-01

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

  18. Heat induced damage detection in composite materials by terahertz radiation

    NASA Astrophysics Data System (ADS)

    Radzie?ski, Maciej; Mieloszyk, Magdalena; Rahani, Ehsan Kabiri; Kundu, Tribikram; Ostachowicz, Wies?aw

    2015-03-01

    In recent years electromagnetic Terahertz (THz) radiation or T-ray has been increasingly used for nondestructive evaluation of various materials such as polymer composites and porous foam tiles in which ultrasonic waves cannot penetrate but T-ray can. Most of these investigations have been limited to mechanical damage detection like inclusions, cracks, delaminations etc. So far only a few investigations have been reported on heat induced damage detection. Unlike mechanical damage the heat induced damage does not have a clear interface between the damaged part and the surrounding intact material from which electromagnetic waves can be reflected back. Difficulties associated with the heat induced damage detection in composite materials using T-ray are discussed in detail in this paper. T-ray measurements are compared for different levels of heat exposure of composite specimens.

  19. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1987-01-01

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

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

    PubMed

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

    2014-10-01

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

  1. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The deformation and failure behavior of graphite/epoxy tubes under biaxial (axial tension and torsion) loading is being investigated. The aim of this research is to increase basic understanding of and provide design information for the biaxial response of graphite/epoxy composites.

  2. Silica-titania composite aerogel photocatalysts by chemical liquid deposition of titania onto nanoporous silica scaffolds.

    PubMed

    Zu, Guoqing; Shen, Jun; Wang, Wenqin; Zou, Liping; Lian, Ya; Zhang, Zhihua

    2015-03-11

    Silica-titania composite aerogels were synthesized by chemical liquid deposition of titania onto nanoporous silica scaffolds. This novel deposition process was based on chemisorption of partially hydrolyzed titanium alkoxides from solution onto silica nanoparticle surfaces and subsequent hydrolysis and condensation to afford titania nanoparticles on the silica surface. The titania is homogeneously distributed in the silica-titania composite aerogels, and the titania content can be effectively controlled by regulating the deposition cycles. The resultant composite aerogel with 15 deposition cycles possessed a high specific surface area (SSA) of 425 m(2)/g, a small particle size of 5-14 nm, and a large pore volume and pore size of 2.41 cm(3)/g and 18.1 nm, respectively, after heat treatment at 600 C and showed high photocatalytic activity in the photodegradation of methylene blue under UV-light irradiation. Its photocatalytic activity highly depends on the deposition cycles and heat treatment. The combination of small particle size, high SSA, and enhanced crystallinity after heat treatment at 600 C contributes to the excellent photocatalytic property of the silica-titania composite aerogel. The higher SSAs compared to those of the reported titania aerogels (<200 m(2)/g at 600 C) at high temperatures combined with the simple method makes the silica-titania aerogels promising candidates as photocatalysts. PMID:25664480

  3. Defects, strain relaxation, and compositional grading in high indium content InGaN epilayers grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Bazioti, C.; Papadomanolaki, E.; Kehagias, Th.; Walther, T.; Smalc-Koziorowska, J.; Pavlidou, E.; Komninou, Ph.; Karakostas, Th.; Iliopoulos, E.; Dimitrakopulos, G. P.

    2015-10-01

    We investigate the structural properties of a series of high alloy content InGaN epilayers grown by plasma-assisted molecular beam epitaxy, employing the deposition temperature as variable under invariant element fluxes. Using transmission electron microscopy methods, distinct strain relaxation modes were observed, depending on the indium content attained through temperature adjustment. At lower indium contents, strain relaxation by V-pit formation dominated, with concurrent formation of an indium-rich interfacial zone. With increasing indium content, this mechanism was gradually substituted by the introduction of a self-formed strained interfacial InGaN layer of lower indium content, as well as multiple intrinsic basal stacking faults and threading dislocations in the rest of the film. We show that this interfacial layer is not chemically abrupt and that major plastic strain relaxation through defect introduction commences upon reaching a critical indium concentration as a result of compositional pulling. Upon further increase of the indium content, this relaxation mode was again gradually succeeded by the increase in the density of misfit dislocations at the InGaN/GaN interface, leading eventually to the suppression of the strained InGaN layer and basal stacking faults.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Jing; Wang, Lixi; Zhang, Qitu

    2015-09-01

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

  5. Fabrication of Composite Material Using Gettou Fiber by Injection Molding

    NASA Astrophysics Data System (ADS)

    Setsuda, Roy; Fukumoto, Isao; Kanda, Yasuyuki

    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.

  6. Compositions for enhancing hydroysis of cellulosic material by cellulolytic enzyme compositions

    SciTech Connect

    Quinlan, Jason; Xu, Feng; Sweeney, Matthew; Johansen, Katja Salomon

    2014-09-30

    The present invention relates to compositions comprising a GH61 polypeptide having cellulolytic enhancing activity and an organic compound comprising a carboxylic acid moiety, a lactone moiety, a phenolic moiety, a flavonoid moiety, or a combination thereof, wherein the combination of the GH61 polypeptide having cellulolytic enhancing activity and the organic compound enhances hydrolysis of a cellulosic material by a cellulolytic enzyme compared to the GH61 polypeptide alone or the organic compound alone. The present invention also relates to methods of using the compositions.

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

    NASA Astrophysics Data System (ADS)

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

    1991-10-01

    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.

  8. Development of ammonia sensors by using conductive polymer/hydroxyapatite composite materials.

    PubMed

    Huixia, Li; Yong, Liu; Lanlan, Luo; Yanni, Tan; Qing, Zhang; Kun, Li

    2016-02-01

    In order to improve the gas sensing properties, hydroxyapatite (HAp)-based composites were prepared by mixing with different contents of conductive polymers: polypyrrole (PPy) and polyaniline (PAni). The compositions, microstructures and phase constitutions of polymer/HAp composites were characterized, and the sensing properties were studied using a chemical gas sensing (CGS-8) system. The results showed that, compared to pure HAp, the sensitivities of the composites to ammonia were improved significantly. 5%PPy/HAp and 20%PAni/HAp composites exhibited the best sensitivities to ammonia, and the sensitivities at 500ppm were 86.72% and 86.18%, respectively. Besides, the sensitivity of 5%PPy/HAp at 1000ppm was up to 90.7%. Compared to pure PPy and PAni, the response and the recovery time of 5%PPy/HAp and 20%PAni/HAp at 200ppm were shortened several times, and they were 24s/245s and 15s/54s, respectively. In addition, the composites showed a very high selectivity to ammonia. The mechanism for the enhancement of the sensitivity to ammonia was also discussed. The polymer/HAp composites are very promising in applications of ammonia sensors. PMID:26652394

  9. Optimization model coupling both chemical compositions and high-temperature characteristics of sintering materials for sintering burden

    NASA Astrophysics Data System (ADS)

    Li, Ke-jiang; Zhang, Jian-liang; Liu, Zheng-jian; Su, Bu-xin; Kong, Ling-tan; Yang, Tian-jun

    2014-03-01

    We developed a mathematical optimization model coupling chemical compositions and high-temperature characteristics of sintering materials, targeting the best quality and lowest cost. The simplex algorithm was adopted to solve this model. Four kinds of imported iron ores, two kinds of Chinese iron ore concentrates, and two kinds of fluxes were selected to verify both the model and the algorithm. The results confirmed the possibility of considering both chemical compositions and high-temperature characteristics of iron ores in the optimization model. This model provides a technical roadmap to obtain a precise mathematical correlation between the lowest cost and the grade of iron in sinters based on the condition of given raw materials, which can provide a reference to adjust the grade of iron in the sintering process for enterprise.

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    The Alpha Particle X-ray Spectrometer (APXS) onboard the Mars Exploration Rover Spirit continues to determine the elemental composition of samples at Gusev Crater. Starting around sol 600 the rover descended Husband Hill, which is part of the Columbia Hills, visited the inner basin with a large dune field, called 'El Dorado', and parked at Low Ridge to conserve energy during the martian winter. Many unique samples were discovered by the instruments onboard Spirit during her downhill traverse. Here, we report only on the chemical data obtained by the APXS. The compositions of some of the soil samples are comparable to the mean soil determined along the earlier traverse. However, a light-toned subsurface sample (disturbed by the rover wheels), called Dead Sea Samra , showed the highest sulfur content of all soil samples, the lowest Na, Mg, Al, Cl, K, Ca, Ti, Mn, and Zn, among the lowest Si and P, and among the highest Cr, Fe and Ni. Assuming ferric sulfate as a major mineral, large amounts of a pure silica phase must be present. Color and quantity of Dead Sea Samra resemble somewhat an earlier soil called Paso Robles , though the latter is a mixture of sulfates with phosphate-rich soil. Manganese in Dead Sea Samra is so low that the Fe/Mn ratio exceeds 300, a value that has never been found previously on Mars (Fe/Mn ratio of 46 for Gusev basalts), indicating that only Fe(3+) 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.

  12. 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...

  13. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  15. Chemical composition of Mars

    NASA Technical Reports Server (NTRS)

    Morgan, J. W.; Anders, E.

    1979-01-01

    The chemical composition of Mars is estimated from the cosmochemical model of Ganapathy and Anders (1974) with additional petrological and geophysical constraints. The model assumes that planets and chondrites underwent the same fractionation processes in the solar nebula, and constraints are imposed by the abundance of the heat-producing elements, U, Th and K, the volatile-rich component and the high density of the mantle. Global abundances of 83 elements are presented, and it is noted that the mantle is an iron-rich garnet wehrlite, nearly identical to the bulk moon composition of Morgan at al. (1978) and that the core is sulfur poor (3.5% S). The comparison of model compositions for the earth, Venus, Mars, the moon and a eucrite parent body suggests that volatile depletion correlates mainly with size rather than with radial distance from the sun.

  16. Biosorption of heavy metal ions from aqueous solutions by short hemp fibers: Effect of chemical composition.

    PubMed

    Pejic, Biljana; Vukcevic, Marija; Kostic, Mirjana; Skundric, Petar

    2009-05-15

    Sorption potential of waste short hemp fibers for Pb(2+), Cd(2+) and Zn(2+) ions from aqueous media was explored. In order to assess the influence of hemp fiber chemical composition on their heavy metals sorption potential, lignin and hemicelluloses were removed selectively by chemical modification. The degree of fiber swelling and water retention value were determined in order to evaluate the change in accessibility of the cell wall components to aqueous solutions due to the fiber modification. The effects of initial ion concentration, contact time and cosorption were studied in batch sorption experiments. The obtained results show that when the content of either lignin or hemicelluloses is progressively reduced by chemical treatment, the sorption properties of hemp fibers are improved. Short hemp fibers are capable of sorbing metal ions (Pb(2+), Cd(2+) and Zn(2+)) from single as well as from ternary metal ion solutions. The maximum total uptake capacities for Pb(2+), Cd(2+) and Zn(2+) ions from single solutions are the same, i.e. 0.078mmol/g, and from ternary mixture 0.074, 0.035 and 0.035mmol/g, respectively. PMID:18778893

  17. Policosanol content and composition in perilla seeds.

    PubMed

    Adhikari, Prakash; Hwang, Keum Taek; Park, Jae Nam; Kim, Choong Ki

    2006-07-26

    Policosanols, long-chain alcohols, have many beneficial physiological activities. Contents and compositions in perilla seeds (Perilla frutescens) produced in Korea and China were determined. Waxy materials were extracted from perilla seeds using hot hexane. Yield of the waxy materials from perilla seeds was 72.1 mg/100 g of dry weight. Contents and compositions of the waxy materials and policosanols were identified and quantified by TLC, HPLC, and GC. Major components of the waxy materials from Korean and Chinese perilla seeds were policosanols (25.5 and 34.8%, respectively), hydrocarbons (18.8 and 10.5%), wax esters, steryl esters and aldehydes (53.0 and 49.8%), acids (1.7 and 2.1%), and triacylglycerols (1.0 and 2.9%), determined by HPLC. For comparison, waxy materials of sesame seeds were also analyzed. Yield of the waxy materials from sesame seeds were 8.6 mg/100 g. Less than 5% policosanols were detected in the waxy materials extracted from sesame seeds produced in Korea and China. Wax esters or steryl esters accounted for 93-95% of the sesame waxy materials. Policosanols in the perilla seeds were composed of 67-68% octacosanol, 16-17% hexacosanol, 6-9% triacontanol, and others. PMID:16848517

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

    SciTech Connect

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

    1986-05-01

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

  19. Computing Equilibrium Chemical Compositions

    NASA Technical Reports Server (NTRS)

    Mcbride, Bonnie J.; Gordon, Sanford

    1995-01-01

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

  20. NDE of composite materials by thermal method and shearography

    NASA Astrophysics Data System (ADS)

    Bison, Paolo G.; Bressan, Chiara; Cavaccini, Giovanni; Ciliberto, Antonio; Grinzato, Ermanno G.

    1997-04-01

    This paper reports a comparison among different thermal techniques and shearography applied to a sandwich panel of composite material containing simulated defects. In particular, the detectability of the defects and the evaluation of the planar extension are examined. An important feature is also the classification of different kinds of defects. The experimental and data processing procedures are described for all methods. For the thermal method, a mathematical simulation of the thermal problem allows us to better design the test. Automatic processing of data are presented giving outputs very simple to understand.

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

    PubMed

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

    2013-12-01

    Investigations were conducted to evaluate the effects of pod storage (as a means of pulp preconditioning) and fermentation on the chemical composition and physical characteristics of Ghanaian cocoa beans. A 4??2 full factorial design with factors as pod storage (0, 7, 14, 21days) and cocoa treatment (fermented and unfermented) were conducted. Samples were analyzed for their chemical composition (moisture, crude fat, crude protein, ash and carbohydrate content) and mineral content using standard analytical methods. The physical qualities of the beans were analyzed for their proportions of cocoa nibs, shells and germ. Fermentation and increasing pod storage resulted in significant (P?content of the beans while carbohydrate content increased from 15.47% to 24.93% with both treatments. As well, increasing pod storage and fermentation significantly (P?content of the beans from while reductions in Mg and K occurred. Amongst the minerals studied, potassium was the most abundant mineral followed by magnesium, phosphorus and calcium in the fermented cocoa beans. Proportion of cocoa nibs also increased from with increasing pod storage and fermentation whiles reductions in shell content and no appreciable changes in germ proportions were noted. PMID:24426021

  2. Enhanced mechanical properties of metallic glass matrix composites formed by chemical partitioning

    NASA Astrophysics Data System (ADS)

    Kim, C. P.; Hays, C. C.; Johnson, W. L.

    2000-03-01

    Results of Charph impact ,three point bending, compression , and tensile tests are presented for a composite material based on bulk metallic glass forming compositions in the Zr-Ti-Cu-Ni-Nb-Be alloy system. This newly designed material exhibits both improved toughness and large plastic strain to failure. The remarkable glass forming ability of bulk metallic glasses allows for the preparation of ductile metal reinforced composites with a bulk metallic glass matrix via in-situ processing;i.e. chemical partitioning. In-situ nucleation and growth of ductile phase inclusions in the glass(e.g. ductile phase dendrite growth) during solidification from the melt. The incorportation of a ductile metal phase into a metallic glass matrix; this stabilizes crack growth in the matrix and extends the composite strain to failure. These ductile metal particles impose intrinsic geometrical constraints on the bulk metallic glass matrix that leads to the generation of multiple shear bands under mechanical loading.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  4. Properties of a surface contaminated by gaseous products of polymer composition materials under vacuum conditions

    NASA Astrophysics Data System (ADS)

    Kalashnikov, E. V.; Kalashnikova, S. N.; Tomeev, K. A.

    2014-02-01

    Optical properties and chemical composition of a surface that is contaminated by molecular flows consisting of gaseous products of polymer composition materials (e.g., EKOM-2 enamel) are experimentally studied. The polymer materials are irradiated using a short-wavelength source with a luminous intensity of 6 10-4 W/cm2 sr in the wavelength interval 90-320 nm in a vacuum chamber that is evacuated to a pressure of 10-4-10-3 Pa. An analytical solution is obtained for the problem of radiation fluxes in scattering and absorbing medium of precipitate on a mirror surface, and a relation of model absorption and scattering coefficients for optical radiation in such medium and transport coefficients of the Gurevich theory of turbid medium is demonstrated.

  5. Effect of cooking on the chemical composition of low-salt, low-fat Wakame/olive oil added beef patties with special reference to fatty acid content.

    PubMed

    Lpez-Lpez, I; Cofrades, S; Caeque, V; Daz, M T; Lpez, O; Jimnez-Colmenero, F

    2011-09-01

    Changes in chemical composition, with special reference to fatty acids, as affected by cooking, were studied in low-salt (0.5%)/low-fat patties (10%) with added Wakame (3%) and partial or total replacement of pork backfat with olive oil-in-water emulsion. The addition of Wakame and olive oil-in-water emulsion improved (P < 0.05) the binding properties and the cooking retention values of moisture, fat, fatty acids and ash, which were close to 100%. Partial and total replacement of animal fat with olive oil-in-water emulsion reduced (P < 0.05) saturated fatty acids (SFAs), while total replacement also reduced (P < 0.05) polyunsaturated fatty acid (PUFAs) contents. The fatty acid concentration in cooked patties was affected by product formulation. Unlike the case of all animal fat patties, when olive oil was added the cooking process increased (P < 0.05) SFAs, monounsaturated fatty acids (MUFAs) and PUFA n-3 (linolenic acid) and n-6 (linoleic acid) contents. Cooked formulated patties with seaweed and partial or total replacement of pork backfat by oil-in-water emulsion and with seaweed added were less calorie-dense and had lower SFAs levels, while samples with olive oil had higher MUFAs levels. PMID:21497025

  6. Prediction of true metabolizable energy from chemical composition of wheat milling by-products for ducks.

    PubMed

    Wan, H F; Chen, W; Qi, Z L; Peng, P; Peng, J

    2009-01-01

    The present study was conducted to evaluate the effect of chemical composition of wheat by-products on the TME value to ducks and to establish the prediction models estimating TME. Seven representative samples were selected from 23 wheat by-products millings samples based on the neutral detergent fiber (NDF) content. According to the Sibbald method, male Cherry Valley ducks were chosen to assay the TME of 7 representative samples. Stepwise regression analysis was performed to establish the prediction equations of TME using CP, ether extract (EE), NDF, acid detergent fiber, crude fiber, and gross energy (GE) as independent variables. The NDF, CP, and DM of 23 samples of wheat by-product averaged to be 33.39 +/- 11.04%, 19.2 +/- 3.25%, 87.17 +/- 0.95%, respectively. The TME values of 7 representative samples averaged 12.02 MJ/kg, with much larger CV than GE (17.72 vs. 2.82%). The crude fiber, NDF, acid detergent fiber were highly but negatively correlated with TME (P < 0.01), in which the greatest correlation coefficient (r = -0.969) was observed between NDF and TME. No significant correlation of CP, EE, ash, and GE to TME was found among the 7 representative samples. The optimal equation in terms of R(2) from using a single chemical analysis was obtained in the total group: TME = -0.1564NDF + 17.4696 (R(2) = 0.94, P = 0.0003), and the TME prediction equation was improved by the addition of the EE and CP content to sequential analysis: TME = -0.17NDF + 0.98EE - 0.27CP + 19.31 (R(2) = 0.99, residual SD = 0.35, P < 0.01). The results of present study suggest that NDF could be used as an effective indicator for the prediction of the TME value of wheat by-products for ducks. PMID:19096062

  7. 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)

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

    2011-07-01

    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.

  8. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  9. Metal removal of cyanobacterial exopolysaccharides by uronic acid content and monosaccharide composition.

    PubMed

    Ozturk, Sahlan; Aslim, Belma; Suludere, Zekiye; Tan, Sema

    2014-01-30

    In the present study, chromium, cadmium and metal mixed (chromium+cadmium) removal and its association with exopolysaccharides and uronic acids production in Synechocystis sp. BASO671 were investigated. It was investigated that BASO671 showed different removal ability when exposed to each metal solely and mixed metal. EPS production by BASO671 was increased following exposure to 15 and 35 ppm Cr(VI), Cd(II) and Cr(VI)+Cd(II). Monomer composition of EPS was changed after metal treatment. Uronic acid contents of metal treated cells were higher than control cells of each isolate. Also, glucuronic acid content and galactronic acid content of EPS correlated with uronic acid contents of cells. Scanning electron microscopy and energy dispersive X-ray spectroscopy analysis confirmed that a considerable amount of metals had precipitated on the cell surface. Fourier transform infrared spectrum analysis of EPSs indicated the presence of CH and CO group, which may serve as binding sites for divalent cations. PMID:24299773

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

    PubMed

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

    1993-04-01

    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

  11. Iatrogenic Damage to the Periodontium by Chemicals and Dental Materials.

    PubMed

    Justus, Biju; Sirajuddin, Syed; Gundapaneni, Veenadharini; Biswas, Shriparna; Mn, Kumuda; Mp, Rakesh

    2015-01-01

    The toxicity and tissue reactions to dental materials are receiving more attention as a wide variety of materials are used and as federal agencies demonstrate more concern in this area. A further indication of the importance of the interaction of materials and tissues is the development of recommended standard practices and tests for the biological interaction of materials. PMID:26312092

  12. Iatrogenic Damage to the Periodontium by Chemicals and Dental Materials

    PubMed Central

    Justus, Biju; Sirajuddin, Syed; Gundapaneni, Veenadharini; Biswas, Shriparna; MN, Kumuda; MP, Rakesh

    2015-01-01

    The toxicity and tissue reactions to dental materials are receiving more attention as a wide variety of materials are used and as federal agencies demonstrate more concern in this area. A further indication of the importance of the interaction of materials and tissues is the development of recommended standard practices and tests for the biological interaction of materials. PMID:26312092

  13. Determining material properties of metal-matrix composites by NDE

    SciTech Connect

    Liaw, P.K.; Shannon, R.E.; Clark, W.G. Jr. . Science and Technology Center); Harrigan, W.C. Jr. ); Jeong, H. ); Hsu, D.K. )

    1992-10-01

    This paper reports on Nondestructive evaluation (NDE) which is a promising means of studying silicon carbide particulate (SiC[sub p])-reinforced aluminum metal-matrix composite (MMC) products at various processing stages. Eddy current techniques are effective in characterizing alloy powders and in evaluating the percentage of reinforcement in Al/SiC[sub p] powder mixtures. Ultrasonic methods can be used to identify SiC[sub p] clusters in large-scale, powder metallurgy processed MMC billets, while eddy current techniques can detect near-surface density variations. Ultrasonic techniques can also be used to determine the anisotropic stiffness constants of composite extrusions; the measured moduli are in good agreement with those determined by tensile testing. These results suggest that NDE can be used to provide on-line, closed-loop control of MMC manufacturing.

  14. Effect of glow discharge sintering in the properties of a composite material fabricated by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Cardenas, A.; Pineda, Y.; Sarmiento Santos, A.; Vera, E.

    2016-02-01

    Composite samples of 316 stainless steel and SiC were produced by powder metallurgy. Starting materials were mixed in different proportions and compacted to 700MPa. Sintering stage was performed by abnormal glow discharge plasma with direct current in an inert atmosphere of argon. The process was conducted at a temperature of 1200°C±5°C with a heating rate of 100°C/min. This work shows, the effectiveness of plasma sintering process to generate the first contacts between particles and to reduce vacancies. This fact is confirmed by comparing green and sintered density of the material. The results of porosity show a decrease after plasma sintering. Wear tests showed the wear mechanisms, noting that at higher SiC contents, the wear resistance decreases due to poor matrix-reinforcement interaction and by the porosity presence which causes matrix-reinforcement sliding.

  15. Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment

    NASA Astrophysics Data System (ADS)

    Jin Bae, Eun; Hun Kang, Young; Jang, Kwang-Suk; Yun Cho, Song

    2016-01-01

    The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and tellurium-PEDOT:PSS (Te-PEDOT:PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of PEDOT:PSS and Te-PEDOT:PSS hybrid composites from 787.99 and 11.01 to 4839.92 and 334.68 S cm‑1, respectively was achieved by simple chemical treatment with H2SO4. The power factor of the developed materials could be effectively tuned over a very wide range depending on the concentration of the H2SO4 solution used in the chemical treatment. The power factors of the developed thermoelectric materials were optimized to 51.85 and 284 μW m‑1 K‑2, respectively, which represent an increase of four orders of magnitude relative to the corresponding parameters of the untreated thermoelectric materials. Using the Te-PEDOT:PSS hybrid composites, a flexible thermoelectric generator that could be embedded in textiles was fabricated by a printing process. This thermoelectric array generates a thermoelectric voltage of 2 mV using human body heat.

  16. Enhancement of Thermoelectric Properties of PEDOT:PSS and Tellurium-PEDOT:PSS Hybrid Composites by Simple Chemical Treatment

    PubMed Central

    Jin Bae, Eun; Hun Kang, Young; Jang, Kwang-Suk; Yun Cho, Song

    2016-01-01

    The thermoelectric properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and tellurium-PEDOT:PSS (Te-PEDOT:PSS) hybrid composites were enhanced via simple chemical treatment. The performance of thermoelectric materials is determined by their electrical conductivity, thermal conductivity, and Seebeck coefficient. Significant enhancement of the electrical conductivity of PEDOT:PSS and Te-PEDOT:PSS hybrid composites from 787.99 and 11.01 to 4839.92 and 334.68 S cm−1, respectively was achieved by simple chemical treatment with H2SO4. The power factor of the developed materials could be effectively tuned over a very wide range depending on the concentration of the H2SO4 solution used in the chemical treatment. The power factors of the developed thermoelectric materials were optimized to 51.85 and 284 μW m−1 K−2, respectively, which represent an increase of four orders of magnitude relative to the corresponding parameters of the untreated thermoelectric materials. Using the Te-PEDOT:PSS hybrid composites, a flexible thermoelectric generator that could be embedded in textiles was fabricated by a printing process. This thermoelectric array generates a thermoelectric voltage of 2 mV using human body heat. PMID:26728992

  17. Chemical recycling of scrap composites

    NASA Technical Reports Server (NTRS)

    Allred, Ronald E.; Salas, Richard M.

    1994-01-01

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

  18. Nondestructive evaluation of composite materials by electrical resistance measurement

    NASA Astrophysics Data System (ADS)

    Mei, Zhen

    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.

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

    PubMed

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

    2015-07-01

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

  20. Chemical composition of Mars

    USGS Publications Warehouse

    Morgan, J.W.; Anders, E.

    1979-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    An enhanced scheme for a functional bilayered composite material with shape memory effect has been successfully applied on the microscale to fabricate a thermally controlled microactuator. Fabrication of cantilever-type microactuators from melt spun ribbon of TiNiCu shape memory alloy included electro-chemical polishing followed by focused ion beam milling and ion-assisted chemical vapor deposition of Pt elastic layer. The smallest working microactuator had a volume of 0.9 m3. The structure and thermal stability of the Pt layer have been investigated. The fabricated actuator has been proposed for use as micromechanical nanotweezers for manipulation of submicron- and nano-sized objects. Manipulation of a carbon nanotube bunch has been demonstrated.

  2. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    Various topics relating to composite structural materials for use in aircraft structures are discussed. The mechanical properties of high performance carbon fibers, carbon fiber-epoxy interface bonds, composite fractures, residual stress in high modulus and high strength carbon fibers, fatigue in composite materials, and the mechanical properties of polymeric matrix composite laminates are among the topics discussed.

  3. Sulfur content of carbon steel plate material for dished end manufacture by cold spinning

    SciTech Connect

    Dutta, T.; Chandawale, R.G.; Vanchinath, S.A.

    1999-07-01

    Over many years SA 516 Gr.70 plate material is being used for the construction of boilers and pressure vessels and has become a standard of the industry. However a typical failure of this material during dished end manufacture has troubled the manufacturer on and off. Many times lamellar separation takes place along the central line of the thickness visible at the edges of the dished ends after cold spinning. In this present study the authors have carried out a customized shear test to ascertain the effect of sulfur content on the susceptibility of the SA 516 Gr. 70 plate material to fail by shear along the plane of segregation. This study indicated that the presence of central segregation is a critical factor to induce reduction in the shear strength. As the sulfur content goes down the segregation line disappears and the shear strength also increases. At 0.01% maximum sulfur best results are obtained. It was supported by the field observation of failed dished ends, where failures are observed with plates with typical sulfur content of 0.02% and above.

  4. Chemical Composition of Martian Rocks

    NASA Astrophysics Data System (ADS)

    Brueckner, J.

    2007-05-01

    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 Mssbauer 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  6. Average chemical composition of the lunar surface

    NASA Technical Reports Server (NTRS)

    Turkevich, A. L.

    1973-01-01

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

  7. Effect of packaging materials on the chemical composition and microbiological quality of edible mushroom (Pleurotus ostreatus) grown on cassava peels

    PubMed Central

    Ajayi, Oluwakemi; Obadina, Adewale; Idowu, Micheal; Adegunwa, Mojisola; Kajihausa, Olatundun; Sanni, Lateef; Asagbra, Yemisi; Ashiru, Bolanle; Tomlins, Keith

    2015-01-01

    Edible fungi such as mushrooms are highly perishable and deteriorate few days after harvest due to its high moisture content and inability to maintain their physiological status. In this study, the effect of packaging materials on the nutritional composition of mushroom cultivated from cassava peels was investigated. Mushroom samples were dried at 50°C in a cabinet dryer for 8 h. The dried mushroom samples packaged in four different packaging materials; high density polyethylene (HDPE), polypropylene (PP), laminated aluminum foil (LAF), high density polyethylene under vacuum (HDPEV) were stored at freezing (0°C) temperatures for 12 weeks. Samples were collected at 2-week intervals and analyzed for proximate composition (carbohydrate, protein, fat, fiber, ash, moisture), mineral content (calcium, potassium), vitamin C content, and microbiological qualities (total aerobic count, Pseudomonal count, Coliform count, Staphylococcal count, Salmonella count) using the standard laboratory procedures. Carbohydrate, protein, fat content of dried mushrooms packaged in HDPE at freezing temperature ranged from 45.2% to 53.5%, 18.0% to 20.3%, and 3.2% to 4.3%, while mushrooms in polypropylene ranged from 45.2% to 53.5%, 18.5% to 20.3%, 2.6% to 4.3%. Carbohydrate, protein, fat of mushroom in LAF ranged from 47.8% to 53.5%, 17.3% to 20.3%, and 3.3% to 4.3%, respectively, while carbohydrate, protein, fat of mushroom in HDPEV ranged from 51.1% to 53.5%, 19.5% to 20.3%, and 3.5% to 4.3%. Microbiological analysis showed that total aerobic count, Pseudomonal count, and Staphyloccocal count of dried mushroom ranged from 2.3 to 3.8 log cfu/g, 0.6 to 1.1 log cfu/g, and 0.4 to 0.5 log cfu/g, respectively. In conclusion, dried mushroom in HDPE packaged under vacuum at freezing temperature retained the nutritional constituents than those packaged with other packaging materials. PMID:26288720

  8. Effect of packaging materials on the chemical composition and microbiological quality of edible mushroom (Pleurotus ostreatus) grown on cassava peels.

    PubMed

    Ajayi, Oluwakemi; Obadina, Adewale; Idowu, Micheal; Adegunwa, Mojisola; Kajihausa, Olatundun; Sanni, Lateef; Asagbra, Yemisi; Ashiru, Bolanle; Tomlins, Keith

    2015-07-01

    Edible fungi such as mushrooms are highly perishable and deteriorate few days after harvest due to its high moisture content and inability to maintain their physiological status. In this study, the effect of packaging materials on the nutritional composition of mushroom cultivated from cassava peels was investigated. Mushroom samples were dried at 50°C in a cabinet dryer for 8 h. The dried mushroom samples packaged in four different packaging materials; high density polyethylene (HDPE), polypropylene (PP), laminated aluminum foil (LAF), high density polyethylene under vacuum (HDPEV) were stored at freezing (0°C) temperatures for 12 weeks. Samples were collected at 2-week intervals and analyzed for proximate composition (carbohydrate, protein, fat, fiber, ash, moisture), mineral content (calcium, potassium), vitamin C content, and microbiological qualities (total aerobic count, Pseudomonal count, Coliform count, Staphylococcal count, Salmonella count) using the standard laboratory procedures. Carbohydrate, protein, fat content of dried mushrooms packaged in HDPE at freezing temperature ranged from 45.2% to 53.5%, 18.0% to 20.3%, and 3.2% to 4.3%, while mushrooms in polypropylene ranged from 45.2% to 53.5%, 18.5% to 20.3%, 2.6% to 4.3%. Carbohydrate, protein, fat of mushroom in LAF ranged from 47.8% to 53.5%, 17.3% to 20.3%, and 3.3% to 4.3%, respectively, while carbohydrate, protein, fat of mushroom in HDPEV ranged from 51.1% to 53.5%, 19.5% to 20.3%, and 3.5% to 4.3%. Microbiological analysis showed that total aerobic count, Pseudomonal count, and Staphyloccocal count of dried mushroom ranged from 2.3 to 3.8 log cfu/g, 0.6 to 1.1 log cfu/g, and 0.4 to 0.5 log cfu/g, respectively. In conclusion, dried mushroom in HDPE packaged under vacuum at freezing temperature retained the nutritional constituents than those packaged with other packaging materials. PMID:26288720

  9. Mechanical properties of a metallic composite material based on an aluminum alloy reinforced by dispersed silicon carbide particles

    NASA Astrophysics Data System (ADS)

    Berezovskii, V. V.; Solyaev, Yu. O.; Lur'e, S. A.; Babaitsev, A. V.; Shavnev, A. A.; Kurganova, Yu. A.

    2015-10-01

    The mechanical properties of a composite material with a matrix of aluminum alloy D16 reinforced with dispersed silicon carbide particles have been studied. The physicomechanical properties (density, elastic modulus, ultimate tensile strength, and limiting strains) of the composite material with various filler contents are determined experimentally. The experimental results are compared to the results of a theoretical simulation obtained using elastic and elastoplastic models of the composite material. The experimental and the calculated mechanical properties of the composite material with the volume content of the filler up to 30% agree well with each other.

  10. Development of chemical vapor composite, CVC materials. Status report, October, 1994--March, 1995

    SciTech Connect

    1995-11-01

    A powder/fiber sensor and controller for CVC reactors was successfully designed, fabricated, tested, and modified. A carbon fiber feeder and controller for a CVC SiC reactor was designed and fabricated but has not yet been tested. SiC material was fabricated using SiC powder ranging in size from 30 to 40 microns. SiC was also fabricated using multiple SiC powders off 10, 30, or 90 microns. Still other SiC materials were fabricated using platelets of 30 or 40 microns. The strength of this SiC material was low due to impurities in the material; ways to eliminate material impurities are currently being thoroughly investigated. Data was assembled on the operation and performance of a typical furnace using a metal fan.

  11. Development of composite materials by mechanochemical treatment of post-consumer plastic waste.

    PubMed

    Cavalieri, F; Padella, F

    2002-01-01

    Improvement of mechanical properties of recycled mixed plastic waste is one of the fundamental goals in any recycling process. However, polymer immiscibility makes the development of any effective reprocessing method difficult. In this work, a polymer milling process with liquid CO2 was applied to polymeric mixed waste, obtaining a powder material which was successfully utilized as a matrix for a new composite material. Developed materials have interesting mechanical properties and material performance can easily be improved. Investigations on selected mixtures of PP and PE clearly showed evidence of chemical compatibilization. PMID:12423054

  12. [EDXRF study on the chemical composition and raw material recipe of Jindezhen porcelains in the five dynasties].

    PubMed

    zhang, Mao-lin; Zhou, Jian; Li, Qi-jiang; Wu, Jun-ming; Gan, Ke

    2012-05-01

    Early crafts of porcelain making in Jindezhen were an important issue in ceramic history of China. The chemical composition of white porcelain and celadon samples excavated from Xianghu Kiln in the five dynasties was analyzed using energy dispersive X-ray fluorescence (EDXRF). Raw material recipes of the samples were discussed. The results showed that white porcelain bodies of Xianghu Kiln in the Five Dynasties were made from porcelain stone, while celadon bodies were made from porcelain stone and Zijin clay. Glaze ash and glaze stone were both used in the formula of white porcelain and celadon glaze, and the amount of glaze ash in the celadon was higher than that in the white porcelain samples. PMID:22827103

  13. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

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

    SciTech Connect

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

    2009-09-09

    The {sup 53}Mn-{sup 53}Cr systematics of meteorite samples provide an important high resolution chronometer for early solar system events. Accurate determination of the initial abundance of {sup 53}Mn ({tau}{sub 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 {sup 55}Mn/{sup 52}Cr 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 SiO{sub 2} 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 {approx}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 {sup 55}Mn/{sup 52}Cr versus true {sup 55}Mn/{sup 52}Cr. This approach may be satisfactory for materials of similar composition, but fails when compositions vary significantly. This is best illustrated by the {approx}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.

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

    PubMed

    Zaichick, Vladimir; Zaichick, Sofia; Davydov, German

    2015-03-01

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

  16. Tough Composite Materials

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

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

  17. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

    Technology utilization of fiber reinforced composite materials is discussed in the areas of physical properties, and life prediction. Programs related to the Composite Aircraft Program are described in detail.

  18. Nano-composite materials

    DOEpatents

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

    2010-05-25

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

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

    PubMed

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

    2012-05-01

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

  20. Characterization and versatile applications of low hydrogen content SiOCN grown by plasma-enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Hamm, Steven C.; Waidmann, Jacob; Mathai, Joseph C.; Gangopadhyay, Keshab; Currano, Luke; Gangopadhyay, Shubhra

    2014-09-01

    Low hydrogen content silicon oxycarbonitride (SiOCN) thin films were grown by plasma-enhanced chemical vapor deposition exploiting hydrogen dilution with silane/methane/nitrous oxide or tetramethylsilane/nitrous oxide precursors. The effects of deposition temperature were compared by investigating the compositional, optical, mechanical, and electrical properties of films grown at 100 C, 250 C, and 400 C at thicknesses ranging from 50 nm to 10 ?m. The dielectric constant and high breakdown strength of the films remain relatively constant at between 4-5 and 6.8 0.2 MV cm-1 to 9.1 0.3 MV cm-1, respectively, despite the differences in deposition temperature. Other properties of the films include excellent transparency in the visible regime, high nanoindentation hardness (4 to 12 GPa), and relatively low measured stress on Si (-20 to -300 MPa). Overall, the results of this work show that these SiOCN films can be used in a wide variety of applications, including as a dielectric within high voltage capacitors, transparent abrasion-resistant coatings for plastic windows, coatings on flexible substrates, a metal diffusion barrier for low-k dielectrics and polymer films, or within various microelectronic fabrication steps or systems.

  1. Computational scheme for ab-initio predictions of chemical compositions interfaces realized by deposition growth

    NASA Astrophysics Data System (ADS)

    Rohrer, Jochen; Hyldgaard, Per

    2011-09-01

    We present a novel computational scheme to predict chemical compositions at interfaces as they emerge in a growth process. The scheme uses the Gibbs free energy of reaction associated with the formation of interfaces with a specific composition as predictor for their prevalence. It explicitly accounts for the growth conditions by rate-equation modeling of the deposition environment. The Bell-Evans-Polanyi principle motivates our emphasis on an effective nonequilibrium thermodynamic description inspired by chemical reaction theory. We illustrate the scheme by characterizing the interface between TiC and alumina. Equilibrium thermodynamics favors a nonbinding interface, being in conflict with the wear-resistant nature of TiC/alumina multilayer coatings. Our novel scheme predicts that deposition of a strongly adhering interface is favored under realistic conditions.

  2. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  3. Process for the preparation of fiber-reinforced ceramic composites by chemical vapor deposition

    DOEpatents

    Lackey, Jr., Walter J. (Oak Ridge, TN); Caputo, Anthony J. (Knoxville, TN)

    1986-01-01

    A chemical vapor deposition (CVD) process for preparing fiber-reinforced ceramic composites. A specially designed apparatus provides a steep thermal gradient across the thickness of a 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.

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

    NASA Astrophysics Data System (ADS)

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

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

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

    PubMed

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

    2012-08-01

    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

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

    NASA Astrophysics Data System (ADS)

    Schumacher, Shane Christian

    2002-01-01

    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 based composites along with their ultimate failure is a significant barrier to their introduction to new applications. Polymer based composite materials also tend to exhibit rate and time dependent failure characteristics. Lack of knowledge about the rate dependent response and progressive failure of composite structures has led to the current practice of designing these structures with static properties. However, high strain rate mechanical properties can vary greatly from the static properties. The objective of this research is to develop a finite element based failure analysis tool for composite materials that incorporates strain rate hardening effects in the material failure model. The analysis method, referred to as multicontinuum theory (MCT) retains the identity of individual constituents by treating them as separate but linked continua. Retaining the constituent identities allows one to extract continuum phase averaged stress/strain fields for the constituents in a routine structural analysis. Time dependent failure is incorporated in MCT by introducing a continuum damage model into MCT. In addition to modeling time and rate dependent failure, the damage model is capable of capturing the nonlinear stress-strain response observed in composite materials.

  7. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    Progress is reported in studies of constituent materials composite materials, generic structural elements, processing science technology, and maintaining long-term structural integrity. Topics discussed include: mechanical properties of high performance carbon fibers; fatigue in composite materials; experimental and theoretical studies of moisture and temperature effects on the mechanical properties of graphite-epoxy laminates and neat resins; numerical investigations of the micromechanics of composite fracture; delamination failures of composite laminates; effect of notch size on composite laminates; improved beam theory for anisotropic materials; variation of resin properties through the thickness of cured samples; numerical analysis composite processing; heat treatment of metal matrix composites, and the RP-1 and RP2 gliders of the sailplane project.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  9. Chemical Compositions of Stars

    NASA Astrophysics Data System (ADS)

    Leckrone, D.; Murdin, P.

    2000-11-01

    In 1835, in a famously inaccurate forecast, the French philosopher Auguste Comte wrote of stars that, `We understand the possibility of determining their shapes, their distances, their sizes and their movements; whereas we would never know how to study by any means their chemical composition…'. At the close of the 20th century the accurate measurement of the abundances of the chemical elements in...

  10. Dispersion of crystalline powder materials in gaseous media of different chemical compositions

    NASA Astrophysics Data System (ADS)

    Klyavin, O. V.; Drinberg, A. S.; Chernov, Yu. M.; Shpeizman, V. V.

    2012-05-01

    The process of grinding of rutile and barite crystalline powders in a laboratory ball mill in different types of gaseous media (air, nitrogen, helium) has been investigated. Comparative evaluations of the intensity of the dispersion of these minerals have been performed and the particle sizes of powders obtained in different modes of their dispersion have been measured. A sharp increase in the intensity of this process in the helium medium as compared to the air and nitrogen media has been revealed and ultrafine-grained particles of barite powders have been obtained. The results of the performed investigations have demonstrated that the helium medium can be recommended for producing nanoparticles of powder materials in modern types of ball and bead mills with a drastic decrease in the time and energy consumptions required for their preparation.

  11. Rapid determination of methanol content in paper materials by alkaline extraction, coupled with headspace analysis.

    PubMed

    Zhang, Chun-Yun; Li, Ling-Ling; Chai, Xin-Sheng; Barnes, Donald G

    2014-07-11

    This study reports on a rapid method for the determination of methanol in paper-based materials by alkaline extraction, coupled with headspace analysis. Methanol partition equilibria between solid-liquid phases and vapor-liquid phases were conducted in two separate containers, from which an equation for calculating the total methanol content in the original paper sample was derived. It was found that the extraction equilibrium of methanol from solid sample could be achieved within 5min at room temperature using a high-speed disintegrator, and a subsequent neutralization step is an effective way to prevent methanol from being regenerated at high temperature during headspace equilibration. The results showed that the relative standard deviations for reproducibility tests were in the range of 1.86-6.03%, and the recoveries were in the range of 92.3-107%. The present method is simple and practical; it can be an efficient tool for quantifying the methanol content in paper-based materials and thus play an important role in the investigation of methanol migration behavior in food and beverage packaging. PMID:24861784

  12. 3-D Braided, continuous fiber ceramic composites produced by chemical vapor infiltration. Final report, 18 January 1991-2 January 1992

    SciTech Connect

    Mello, M.D.; Florentine, R.A.

    1993-12-01

    Continuous fiber reinforced ceramic composites have been successfully fabricated by chemical vapor infiltration of silicon carbide and silicon nitride matrix materials. Fiber preforms were three dimensionally braided with Nicalon(TM) and Nextel(TM) fiber materials forming a network of through thickness fiber architectures. Three unique material compositions were produced with the objective of demonstrating the capability of braiding brittle ceramic fibers and producing quality composites structurally capable of performing in a ballistic environment. It is anticipated that the continuous fiber architecture will be a significant technical advantage towards improvements in ceramic armor applications where non-catastrophic failure and increased toughness are a concern.

  13. Erosion of composite materials

    NASA Technical Reports Server (NTRS)

    Springer, G. S.

    1980-01-01

    A model for describing the response of uncoated and coated fiber reinforced composites subjected to repeated impingements of liquid (rain) droplets is presented. The model is based on the concept that fatigue is the dominant factor in the erosion process. Algebraic expressions are provided which give the incubation period, the rate of mass loss past the incubation period, and the total mass loss of the material during rain impact. The influence of material properties on erosion damage and the protection offered by different coatings are discussed and the use of the model in the design in the design of structures and components is illustrated.

  14. The Chemical Composition of Honey

    ERIC Educational Resources Information Center

    Ball, David W.

    2007-01-01

    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

  15. The Chemical Composition of Honey

    ERIC Educational Resources Information Center

    Ball, David W.

    2007-01-01

    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…

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  17. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    The purpose of the RPI composites program is to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, reliability and life prediction. Concommitant goals are to educate engineers to design and use composite materials as normal or conventional materials. A multifaceted program was instituted to achieve these objectives.

  18. Composite material radomes

    NASA Astrophysics Data System (ADS)

    Carbone, R.; Simon, J.-Y.

    1987-06-01

    The fabrication of radomes from composite materials, for naval and aeronautical applications including the Mirage II, F1, and Mirage 2000, is discussed. The diverse radioelectric and mechanical requirements of radomes are best met in the average-temperature regime by reinforced plastics, and in the elevated supersonic regime by ceramic materials. The structural criteria of radomes concerning aerodynamic, inertial, and vibrational loading, and the environmental criteria concerning temperature, sand and rain erosion, and lightning effects, are reviewed. Materials considered for radome fabrication include modified polyesters, epoxies, and thermostable resins, using glass, silica, and aramide tissues or threads as the reinforcements. The advantages and disadvantages of the various fabrication methods, and the fabrication of monolithic radomes by winding and by using preformed weaves, are also discussed.

  19. Aqueous chemical wash compositions

    SciTech Connect

    Bannister, C.E.

    1987-07-21

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

  20. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, Robert G.; Wiberley, Stephen E.

    1988-01-01

    A decade long program to develop critical advanced composite technology in the areas of physical properties, structural concept and analysis, manufacturing, reliability, and life predictions is reviewed. Specific goals are discussed. The status of the chemical vapor deposition effects on carbon fiber properties; inelastic deformation of metal matrix laminates; fatigue damage in fibrous MMC laminates; delamination fracture toughness in thermoplastic matrix composites; and numerical analysis of composite micromechanical behavior are presented.

  1. Composite material and method for production of improved composite material

    NASA Technical Reports Server (NTRS)

    Farley, Gary L. (Inventor)

    1996-01-01

    A laminated composite material with improved interlaminar strength and damage tolerance having short rods distributed evenly throughout the composite material perpendicular to the laminae. Each rod is shorter than the thickness of the finished laminate, but several times as long as the thickness of each lamina. The laminate is made by inserting short rods in layers of prepreg material, and then stacking and curing prepreg material with rods inserted therethrough.

  2. Production and application of chemical fibers with special properties for manufacturing composite materials and goods of different usage

    NASA Technical Reports Server (NTRS)

    Levit, R.

    1993-01-01

    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 heat-resistant fibers, fire-resistant fibers, thermotropic fibers, fibers for medical application, and textile structures. The second group contains refractory fibers, chemoresistant and antifriction fibers, fibers on the basis of polyvinyl alcohol, microfiltering films, and paperlike and nonwoven materials. In cooperation with NPO 'Chimvolokno' MYTITSHI, we developed and started producing heat-resistant high-strength fibers on the base of polyhetarearilin and aromatic polyimides (SVM and terlon); heat-resistant fibers on the base of polyemede (aramid); fire-retardant fibers (togilen); chemoresistant and antifriction fibers on the basis of homo and copolymers of polytetrafluoroethylene (polyfen and ftorin); and water soluble, acetylated, and high-modulus fibers from polyvinyl alcohol (vylen). Separate reports will deal with textile structures and thermotropic fibers, as well as with medical fibers. One of the groups of refractory fibers carbon fibers (CF) and the corresponding paperlike nonwoven materials are discussed in detail. Also, composite materials (CM) and their base, which is the subject of the author's research since 1968, is discussed.

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

    NASA Astrophysics Data System (ADS)

    Kwok, Kinghong

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  6. Physical and chemical ageing/degradation of polymers and composites as detected by positron annihilation lifetime spectroscopy

    NASA Astrophysics Data System (ADS)

    Hill, A. J.

    1999-12-01

    Use of positrons (positively charged electrons) to probe the physical and chemical "state" of polymers and composites offers a molecular level method of detecting the onset of degradation before the associated physical or mechanical property changes become catastrophic. Such measurements can be used to provide an early warning of ageing/degradation and to monitor the level of degradation over the service lifetime of the part. The method discussed in the present work relies on the positron detection of the local electron density in the material via positron annihilation lifetime spectroscopy (PALS). The local electron density at the annihilation sites within the material can change due to physical ageing (no bond breaking) and/or chemical degradation (hydrolysis, oxidation, etc.). Measurements of the ageing-induced changes in the positron lifetime can be correlated with the molecular-level rearrangements responsible for deterioration of properties. By using PALS in combination with chemically site-specific techniques, such as nuclear magnetic resonance (NMR) and infrared (IR), an understanding of the degradation process can be achieved and procedures for mitigating the damage can be developed (e.g. stabilizers). Examples of PALS-detected ageing/degradation in structural plastics poly(carbonate), poly(ethylene terephthalate), and poly(propylene), and poly(imide)/carbon fibre composites are given.

  7. Composite Materials: An Educational Need.

    ERIC Educational Resources Information Center

    Saliba, Tony E.; Snide, James A.

    1990-01-01

    Described is the need to incorporate the concepts and applications of advanced composite materials into existing chemical engineering programs. Discussed are the justification for, and implementation of topics including transport phenomena, kinetics and reactor design, unit operations, and product and process design. (CW)

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  9. Composite structural materials

    NASA Technical Reports Server (NTRS)

    Loewy, R.; Wiberley, S. E.

    1986-01-01

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

  10. Electrically conductive composite material

    DOEpatents

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

    1989-01-01

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

  11. Electrically conductive composite material

    DOEpatents

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

    1988-06-20

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

  12. Composite Structural Materials

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    The development and application of filamentary composite materials, is considered. Such interest is based on the possibility of using relatively brittle materials with high modulus, high strength, but low density in composites with good durability and high tolerance to damage. Fiber reinforced composite materials of this kind offer substantially improved performance and potentially lower costs for aerospace hardware. Much progress has been made since the initial developments in the mid 1960's. There were only limited applied to the primary structure of operational vehicles, mainly as aircrafts.

  13. Electrically conductive composite material

    DOEpatents

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

    1989-05-23

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

  14. Thermoelastic constitutive equations for chemically hardening materials

    NASA Technical Reports Server (NTRS)

    Shaffer, B. W.; Levitsky, M.

    1974-01-01

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

  15. Thermo-chemical fuel removal from porous materials by oxygen and nitrogen dioxide

    NASA Astrophysics Data System (ADS)

    Möller, S.; Alegre, D.; Kreter, A.; Petersson, P.; Esser, H. G.; Samm, U.

    2014-04-01

    Thermo-chemical removal (TCR), or baking in reactive gases, is a candidate method to control the co-deposit related tritium inventory in fusion devices. TCR can be understood as reaction-diffusion processes in a porous material. O2-TCR was applied to 150-550 nm thick a-C:D layers with similar textures. A linear relation between the integral TCR rate and the layer thickness, as predicted by the understanding, was observed in the experiment, i.e. the time to remove the hydrogen inventory is independent of its initial amount. TCR with nitrogen dioxide (NO2) at temperatures of 200-350 °C was conducted with a set of a-C:D and W-C-H layers. At 350 °C NO2 removed ˜ 15% porosity a-C:D within 3 min. The O retention in remaining a-C:D was ≈ 1017 O cm-2. An activation energy of ≈ 0.78 eV for reactions of NO2 with D and C was determined. The results were applied for predictions of the TCR effectivity in ITER. The treatment of W-C-H led to O uptake (O/W ≈ 2-3), while W and C contents remained unchanged.

  16. Composite Material Switches

    NASA Technical Reports Server (NTRS)

    Javadi, Hamid (Inventor)

    2002-01-01

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

  17. Composite Material Switches

    NASA Technical Reports Server (NTRS)

    Javadi, Hamid (Inventor)

    2001-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Kahl, S.; Osikowicz, W.

    2013-08-01

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

  19. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

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

  20. Combinatorial synthesis of inorganic or composite materials

    DOEpatents

    Goldwasser, Isy (Palo Alto, CA); Ross, Debra A. (Mountain Ranch, CA); Schultz, Peter G. (La Jolla, CA); Xiang, Xiao-Dong (Danville, CA); Briceno, Gabriel (Baldwin Park, CA); Sun, Xian-Dong (Fremont, CA); Wang, Kai-An (Cupertino, CA)

    2010-08-03

    Methods and apparatus for the preparation and use of a substrate having an array of diverse materials in predefined regions thereon. A substrate having an array of diverse materials thereon is generally prepared by delivering components of materials to predefined regions on a substrate, and simultaneously reacting the components to form at least two materials or, alternatively, allowing the components to interact to form at least two different materials. Materials which can be prepared using the methods and apparatus of the present invention include, for example, covalent network solids, ionic solids and molecular solids. More particularly, materials which can be prepared using the methods and apparatus of the present invention include, for example, inorganic materials, intermetallic materials, metal alloys, ceramic materials, organic materials, organometallic materials, nonbiological organic polymers, composite materials (e.g., inorganic composites, organic composites, or combinations thereof), etc. Once prepared, these materials can be screened for useful properties including, for example, electrical, thermal, mechanical, morphological, optical, magnetic, chemical, or other properties. Thus, the present invention provides methods for the parallel synthesis and analysis of novel materials having useful properties.

  1. Origin and Bulk Chemical Composition of Mercury

    NASA Astrophysics Data System (ADS)

    Prentice, Andrew J. R.; Jontof-Hutter, Daniel

    2005-01-01

    The planet Mercury is remarkable because its mean uncompressed density ˜5.3 g/cc implies a Fe-Ni mass content of ˜67%. This is more than twice the ˜32% metal fractions of Venus and Earth. This factor coupled with other marked chemical and isotopic differences between the four terrestrial planets points to the conclusion that each planet ?received the overwhelming majority of its mass from a narrow compositionally-distinct annulus of material around the Sun? (Drake & Righter 2002 Nature 416 39; Taylor & Scott 2001 in URL below). This situation finds an explanation within the Modern Laplacian theory of Solar system origin (Prentice 2001 Earth Moon & Planets 87 11; URL: www.lpi.usra.edu/meetings/mercury01). Here the planets condensed from a concentric family of circular gas rings shed by the proto-Solar cloud. The temperatures and mean orbit pressures of the gas rings scale with heliocentric distance r as T ~ 1/r0.9 and p ˜1/r4.0 respectively. At Mercury?s orbit T = 1640 K p= 0.16 bar and the three primary equilibrium condensates are Fe-Ni (67 %) gehlenite (26.1%) and spinel (4.1%). A simple 2-zone structural model of Mercury based on this mix has mean density 5.43 g/cc and axial moment-of-inertia coefficent C/MR2 = 0.325.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    PubMed

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

    2015-03-01

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

  4. Energetic composites and method of providing chemical energy

    DOEpatents

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

    1997-01-01

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

  5. Energetic composites and method of providing chemical energy

    DOEpatents

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

    1997-02-25

    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.

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

    PubMed Central

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

    2013-01-01

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

  7. Chemical compositions of large cluster IDPs

    SciTech Connect

    Flynn, G.J.; Lanzirotti, A.; Sutton, S.R.

    2006-12-06

    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

  8. Spatial-Time Variability of Particulate Material Content and its Composition on the East Siberian Shelf: from Mesoscale to Interannual Variability

    NASA Astrophysics Data System (ADS)

    Dudarev, O.; Charkin, A.; Shakhova, N. E.; Semiletov, I. P.; Gustafsson, O. M.; Vonk, J.; Sanchez-Garcia, L.

    2013-12-01

    Here we present the data obtained in the Russia-US cruises (FEBRAS, NOAA, NSF, and Russian Foundation for Basic Research, RFBR, funded) in 2000, 2003-2005, and in the International Siberian Shelf Study-2008 (ISSS-2008, supported by the Wallenberg Foundation, FEBRAS, NOAA, and RFBR) which characterized a spatial and inter-annual variability in distribution of particulate material (PM), and its organic carbon and stable isotopes content. The role of the coastal zone in lateral transport and fate of terrestrial organic carbon in the East Siberian Arctic Shelf (ESAS) is still not studied well because most recent activities were focused on onshore geomorphologic and geochemical features, while biogeochemical and sedimentation consequences of coastal erosion and riverine runoff in the sea were not studied sufficiently. Dynamics of PM and its composition was studied twice along the Lena river in summer-fall of 2003. Spatial-time dynamics of PM composition (POC and isotopes) along with its mineralogical composition is considered in connection with changing river runoff and wind patterns. It has been found that not the rivers (Lena, Yana, Indigirka, Kolyma), but the coastal erosion is a dominant source of terrestrial particulate organic carbon (POC) into the ESAS. That supports the hypothesis about the dominant role of coastal erosion in the offshore transport of terrestrial organic carbon and sedimentation in the ESAS proposed by Semiletov (DAN, 1999). The PM concentration sharp gradient was found across the frontal zone between 'freshened/high PM' and 'Pacific/low PM' waters. Position of the frontal zone varies significantly from year to year. It is mainly attributed to the difference in atmospheric circulation patterns driven the Arctic Ocean circulation. During storms and surges the PM concentration in the same area increased up to 10-times and higher (up to 80-242 mg/l) in 2000 and 2005 comparing the 2003 and 2004. Values of total PM and other environmental parameters were integrated vertically and spatially for the 'comparison' area using approach proposed by Shakhova et al. (GRL, 2005) to make the first quantitative PM burden estimation (2003 vs 2004).

  9. Chemical composition of Angelica pancicii essential oil determined by liquid and headspace GC-MS techniques.

    PubMed

    Simonovi?, Strahinja R; Stankov-Jovanovi?, Vesna P; Miti?, Violeta D; Ili?, Marija D; Petrovi?, Goran M; Stojanovi?, Gordana S

    2014-02-01

    The essential oil of the Balkan endemic species, Angelica pancicii, obtained by hydrodistillation, was analyzed by GC and GC-MS, applying the liquid injection mode. These results were compared with the chemical composition of volatiles achieved by the "headspace" injection mode, followed by GC and GC-MS (HS-GC-MS). A total of 40 compounds were identified in the essential oil (98.8% of the total oil) and 44 by HS-GC-MS (99.8% of the total oil). The most abundant class of compounds in both cases was monoterpenoids, which formed 92.7% of the essential oil (97.7% by HS-GC-MS) of total identified compounds. The major components in both cases were beta-phellandrene (54.9% and 60.1%, respectively), alpha-pinene (14.5% and 20.1%, respectively) and alpha-phellandrene (4.5% and 4.3%, respectively). PMID:24689308

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

    PubMed

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

    2009-01-01

    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

  11. Sorption of four hydrophobic organic compounds by three chemically distinct polymers: role of chemical and physical composition.

    PubMed

    Guo, Xiaoying; Wang, Xilong; Zhou, Xinzhe; Kong, Xiangzhen; Tao, Shu; Xing, Baoshan

    2012-07-01

    The sorption behavior of four hydrophobic organic contaminants (HOCs) (i.e., phenanthrene, naphthalene, lindane, and 1-naphthol) by three types of polymers namely polyethylene (PE), polystyrene (PS), and polyphenyleneoxide (PPO) was examined in this work. The organic carbon content-normalized sorption coefficients (K(oc)) of phenanthrene, lindane, and naphthalene by PEs of same composition but distinct physical makeup of domains increased with their crystallinity reduction (from 58.7 to 25.5%), suggesting that mobility and abundance of rubbery domains in polymers regulated HOC sorption. Cross-linking in styrene-divinylbenzene copolymer (PS2) created substantial surface area and porosity, thus, K(oc) values of phenanthrene, lindane, naphthalene, and 1-naphthol by PS2 were as high as 274.8, 212.3, 27.4, and 1.5 times of those by the linear polystyrene (PS1). The K(oc) values of lindane, naphthalene, and 1-naphthol by polar PPO were approximately 1-3 orders of magnitude higher than those by PS1, and PPO had comparable sorption for phenanthrene but higher sorption for naphthalene and 1-naphthol than PS2. This can be a result that a portion of O-containing moieties in PPO were masked in the interior part, while leaving the hydrophobic domains exposed outside, therefore demonstrating the great influence of the spatial arrangement of domains in polymers on HOC sorption. PMID:22676433

  12. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy.

    PubMed

    González-Martín, M Inmaculada; Escuredo, Olga; Revilla, Isabel; Vivar-Quintana, Ana M; Coello, M Carmen; Riocerezo, Carlos Palacios; Moncada, Guillermo Wells

    2015-01-01

    The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption. PMID:26540058

  13. Determination of the Mineral Composition and Toxic Element Contents of Propolis by Near Infrared Spectroscopy

    PubMed Central

    González-Martín, M. Inmaculada; Escuredo, Olga; Revilla, Isabel; Vivar-Quintana, Ana M.; Coello, M. Carmen; Palacios Riocerezo, Carlos; Wells Moncada, Guillermo

    2015-01-01

    The potential of near infrared spectroscopy (NIR) with remote reflectance fiber-optic probes for determining the mineral composition of propolis was evaluated. This technology allows direct measurements without prior sample treatment. Ninety one samples of propolis were collected in Chile (Bio-Bio region) and Spain (Castilla-León and Galicia regions). The minerals measured were aluminum, calcium, iron, potassium, magnesium, phosphorus, and some potentially toxic trace elements such as zinc, chromium, nickel, copper and lead. The modified partial least squares (MPLS) regression method was used to develop the NIR calibration model. The determination coefficient (R2) and root mean square error of prediction (RMSEP) obtained for aluminum (0.79, 53), calcium (0.83, 94), iron (0.69, 134) potassium (0.95, 117), magnesium (0.70, 99), phosphorus (0.94, 24) zinc (0.87, 10) chromium (0.48, 0.6) nickel (0.52, 0.7) copper (0.64, 0.9) and lead (0.70, 2) in ppm. The results demonstrated that the capacity for prediction can be considered good for wide ranges of potassium, phosphorus and zinc concentrations, and acceptable for aluminum, calcium, magnesium, iron and lead. This indicated that the NIR method is comparable to chemical methods. The method is of interest in the rapid prediction of potentially toxic elements in propolis before consumption. PMID:26540058

  14. Composite material and method of making

    SciTech Connect

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

    2004-04-20

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

  15. Nanostructured composite reinforced material

    DOEpatents

    Seals, Roland D.; Ripley, Edward B.; Ludtka, Gerard M.

    2012-07-31

    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.

  16. Modified Composite Materials Workshop

    NASA Technical Reports Server (NTRS)

    Dicus, D. L. (Compiler)

    1978-01-01

    The reduction or elimination of the hazard which results from accidental release of graphite fibers from composite materials was studied at a workshop. At the workshop, groups were organized to consider six topics: epoxy modifications, epoxy replacement, fiber modifications, fiber coatings and new fibers, hybrids, and fiber release testing. Because of the time required to develop a new material and acquire a design data base, most of the workers concluded that a modified composite material would require about four to five years of development and testing before it could be applied to aircraft structures. The hybrid working group considered that some hybrid composites which reduce the risk of accidental fiber release might be put into service over the near term. The fiber release testing working group recommended a coordinated effort to define a suitable laboratory test.

  17. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

    Progress and plans are reported for investigations of: (1) the mechanical properties of high performance carbon fibers; (2) fatigue in composite materials; (3) moisture and temperature effects on the mechanical properties of graphite-epoxy laminates; (4) the theory of inhomogeneous swelling in epoxy resin; (5) numerical studies of the micromechanics of composite fracture; (6) free edge failures of composite laminates; (7) analysis of unbalanced laminates; (8) compact lug design; (9) quantification of Saint-Venant's principles for a general prismatic member; (10) variation of resin properties through the thickness of cured samples; and (11) the wing fuselage ensemble of the RP-1 and RP-2 sailplanes.

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

    PubMed

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

    2015-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  20. Improving dry carbon nanotube actuators by chemical modifications, material hybridization, and proper engineering

    NASA Astrophysics Data System (ADS)

    Biso, Maurizio; Ansaldo, Alberto; Ricci, Davide

    2013-04-01

    Low voltage, dry electrochemical actuators can be prepared by using a gel made of carbon nanotubes and ionic liquid.1 Their performance can be significantly improved by combining physical and chemical modifications with a proper engineering. We demonstrated that multi walled carbon nanotubes can be effectively used for actuators preparation;2 we achieved interesting performance improvements by chemically cross linking carbon nanotubes using both aromatic and aliphatic diamines;3 we introduced a novel hybrid material, made by in-situ chemical polymerization of pyrrole on carbon nanotubes, that further boosts actuation by taking advantage of the peculiar properties of both materials in terms of maximum strain and conductivity;4 we investigated the influence of actuator thickness showing that the generated strain at high frequency is strongly enhanced when thickness is reduced. To overcome limitations set by bimorphs, we designed a novel actuator in which a metal spring, embedded in the solid electrolyte of a bimorph device, is used as a non-actuating counter plate resulting in a three electrode device capable of both linear and bending motion. Finally, we propose a way to model actuators performance in terms of purely material-dependent parameters instead of geometry-dependent ones.5

  1. A comparison of composition and emulsifying properties of MFGM materials prepared from different dairy sources by microfiltration.

    PubMed

    Miocinovic, Jelena; Le Trung, Thien; Fredrick, Eveline; Van der Meeren, Paul; Pudja, Predrag; Dewettinck, Koen

    2014-09-01

    Milk fat globule membrane (MFGM), due to its specific nature and composition, is known as material possessing advantageous nutritional as well as technological properties. In this study MFGM materials were produced from several dairy sources such as buttermilk (BM), butter serum (BS) and buttermilk whey (BMW) by microfiltration (MF). The obtained materials, depending on the sources, were called BM-MFGM, BS-MFGM and BMW-MFGM, respectively. The compositions of starting materials and the isolated MFGM materials as well as their emulsifying properties were analyzed and compared. As expected, the MF resulted in enrichment of polar lipids (PLs), major components of MFGM. On dry matter basis, BM-MFGM and BS-MFGM were about 2.5 times higher in PLs compared to their beginning materials while BMW-MFGM was about 8.3 times compared to buttermilk powder (BMP). Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that the microfiltered products still contained a high amount of non-MFGM proteins such as caseins, ?-lactoglobulin, and ?-lactalbumin. Emulsions of 35% soya oil in water were prepared with the mentioned materials using a homogenizer at various pressures. Generally, emulsions prepared with BMP and butter serum powder had significantly higher particle sizes than those prepared with the MFGM materials. This result along with microscopy observation and viscosity measurement indicated the presence of aggregated particles in the former emulsions, probably as a result of lack of surface-active components. The differences in composition, especially in content of PLs and proteins of the materials were the main reasons for the differences in their emulsifying behaviors. PMID:23751553

  2. Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass.

    PubMed

    Calnan, Sonya; Gabriel, Onno; Rothert, Inga; Werth, Matteo; Ring, Sven; Stannowski, Bernd; Schlatmann, Rutger

    2015-09-01

    In this study, various silicon dielectric films, namely, a-SiOx:H, a-SiNx:H, and a-SiOxNy:H, grown by plasma enhanced chemical vapor deposition (PECVD) were evaluated for use as interlayers (ILs) between crystalline silicon and glass. Chemical bonding analysis using Fourier transform infrared spectroscopy showed that high values of oxidant gases (CO2 and/or N2), added to SiH4 during PECVD, reduced the Si-H and N-H bond density in the silicon dielectrics. Various three layer stacks combining the silicon dielectric materials were designed to minimize optical losses between silicon and glass in rear side contacted heterojunction pn test cells. The PECVD grown silicon dielectrics retained their functionality despite being subjected to harsh subsequent processing such as crystallization of the silicon at 1414 C or above. High values of short circuit current density (Jsc; without additional hydrogen passivation) required a high density of Si-H bonds and for the nitrogen containing films, additionally, a high N-H bond density. Concurrently high values of both Jsc and open circuit voltage Voc were only observed when [Si-H] was equal to or exceeded [N-H]. Generally, Voc correlated with a high density of [Si-H] bonds in the silicon dielectric; otherwise, additional hydrogen passivation using an active plasma process was required. The highest Voc ? 560 mV, for a silicon acceptor concentration of about 10(16) cm(-3), was observed for stacks where an a-SiOxNy:H film was adjacent to the silicon. Regardless of the cell absorber thickness, field effect passivation of the buried silicon surface by the silicon dielectric was mandatory for efficient collection of carriers generated from short wavelength light (in the vicinity of the glass-Si interface). However, additional hydrogen passivation was obligatory for an increased diffusion length of the photogenerated carriers and thus Jsc in solar cells with thicker absorbers. PMID:26281016

  3. Photochromic organic-inorganic composite materials prepared by sol-gel processing: Properties and potentials

    SciTech Connect

    Hou, L.; Mennig, M.; Schmidt, H.

    1994-12-31

    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 the authors present their 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. Their 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

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

    PubMed

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

    2007-03-01

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

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

    PubMed

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

    2015-05-01

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

  7. 27 CFR 19.326 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... chemicals produced. 19.326 Section 19.326 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Production Chemical By-Products § 19.326 Spirits content of chemicals produced. All chemicals produced, including chemical...

  8. The foliar endophytic fungal community composition in Cirsium arvense is affected by mycorrhizal colonization and soil nutrient content.

    PubMed

    Eschen, René; Hunt, Stephanie; Mykura, Charlotte; Gange, Alan C; Sutton, Brian C

    2010-01-01

    Foliar fungal endophytes are ubiquitous, but understudied symbionts of most plant species; relatively little is known about the factors affecting their occurrence, diversity and abundance. We tested the effects of soil nutrient content and arbuscular mycorrhizal (AM) colonization on the occurrence of foliar endophytic fungi in Cirsium arvense in two field studies. In the first study, we assessed relationships between soil moisture, organic matter, carbon and nitrogen content and plant water, nitrogen and carbon content and AM colonization and the occurrence of foliar endophytic fungal species. In the second study, we manipulated soil nutrient content and AM colonization of potted seedlings and identified differences in endophytic fungal species composition of the leaves and stems. The results reveal that endophytes can occur either more or less frequently, depending on soil nutrient and plant water content and AM colonization. We propose that these patterns were the result of differences in fungal growth responses to nutrient availability in the leaves, which can be affected by resources obtained from the soil or symbiotic fungi in the roots. PMID:21036343

  9. Evaluation of prediction equations to estimate gross, digestible, and metabolizable energy content of maize dried distillers grains with solubles (DDGS) for swine based on chemical composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to cross-validate prediction equations to estimate the concentration of gross energy (GE), digestible energy (DE), and metabolizable energy (ME) among sources of corn distillers dried grains with solubles (DDGS) with variable chemical composition in growing pigs. Publ...

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

    NASA Astrophysics Data System (ADS)

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

    2008-01-01

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

  11. Aerosols near by a coal fired thermal power plant: chemical composition and toxic evaluation.

    PubMed

    Jayasekher, T

    2009-06-01

    Industrial processes discharge fine particulates containing organic as well as inorganic compounds into the atmosphere which are known to induce damage to cell and DNA, both in vitro and in vivo. Source and area specific studies with respect to the chemical composition, size and shape of the particles, and toxicity evaluations are very much limited. This study aims to investigate the trace elements associated with the aerosol particles distributed near to a coal burning thermal power plant and to evaluate their toxicity through Comet assay. PM(10) (particles determined by mass passing an inlet with a 50% cut-off efficiency having a 10-microm aerodynamic diameter) samples were collected using respirable dust samplers. Twelve elements (Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, Se, Hg, and As) were analyzed using ICP-AES. Comet assay was done with the extracts of aerosols in phosphate buffered saline (PBS). Results show that Fe and Zn were found to be the predominant elements along with traces of other analyzed elements. Spherical shaped ultrafine particles of <1 microm aerodynamic diameter were detected through scanning electron microscope. PM(10) particles near to the coal burning power plant produced comets indicating their potential to induce DNA damage. DNA damage property is found to be depending upon the chemical characteristics of the components associated with the particles besides the physical properties such as size and shape. PMID:19264341

  12. Enhanced Removal of Lead by Chemically and Biologically Treated Carbonaceous Materials

    PubMed Central

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

    2012-01-01

    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 μmol 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. PMID:22629157

  13. Determination of divalent iron content in igneous rocks of ultrabasic, basic and intermediate compositions by a wavelength-dispersive X-ray fluorescence spectrometric method

    NASA Astrophysics Data System (ADS)

    Chubarov, Victor M.; Finkelshtein, Alexandr L.

    2015-05-01

    This paper proposes the quantitative wavelength-dispersive X-ray fluorescence (XRF) technique of divalent iron content determination in igneous rocks and reports specifics of this technique in terms of classifying rocks into ultrabasic, basic, intermediate and acid ones. Unlike the widely used technique of titration, the proposed XRF technique does not require a labor-consuming procedure for sample preparation. In the fields of FeKβ5 line, and FeKβ‧ and FeKβ″ satellites relative intensities of XRF emission spectrum lines are dependent on the valence state of iron in minerals. The ratio FeKβ5/FeKβ1,3 is preferred as the analytical parameter. The XRF method allows divalent iron content (expressed as FeO oxide) over 1.5% to be measured in igneous rocks of ultrabasic and basic compositions by the common calibration equation with the error below 10 rel. %, that is comparable with the error of titrimetric analysis. The samples of igneous rocks of intermediate composition and granodiorites should be analyzed using calibration equations obtained with certified reference materials corresponding in composition to the study samples. For the samples of alkaline rocks the errors of FeO content determination might be in excess of 50 rel. %.

  14. Determination of the composition of counterfeit Heptodin tablets by near infrared chemical imaging and classical least squares estimation.

    PubMed

    Lopes, Marta B; Wolff, Jean-Claude; Bioucas-Dias, Jos M; Figueiredo, Mrio A T

    2009-05-01

    According to the WHO definition for counterfeit medicines, several categories can be established, e.g., medicines containing the correct active pharmaceutical ingredient (API) but different excipients, medicines containing low levels of API, no API or even a substitute API. Obviously, these different scenarios will have different detrimental effects on a patient's health. Establishing the degree of risk to the patient through determination of the composition of counterfeit medicines found in the market place is thus of paramount importance. In this work, classical least squares was used for predicting the composition of counterfeit Heptodin tablets found in a market survey. Near infrared chemical imaging (NIR-CI) was used as a non-destructive measurement technique. No prior knowledge about the origin and composition of the tablets was available. Good API (i.e., lamivudine) predictions were obtained, especially for tablets containing a high API (close to the authentic) dose. Concentration maps of each pure material, i.e., the API (lamivudine) and the excipients microcrystalline cellulose, sodium starch glycollate, rice starch and talc, were estimated. Below 1% of the energy was not explained by the model (residuals percentage) for every pixel in all 12 counterfeit tablets. The similarities among tablets with respect to the total API percentage determined, as well as the corresponding concentration maps, support the classification of the tablets into the different groups obtained in previous work. PMID:19393365

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

    NASA Astrophysics Data System (ADS)

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

    1998-06-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1998-06-01

    We report abundances of sixty-three major, trace, and rare earth elements in the upper crust in five tectonic units (the interior and southern margin of the North China craton, the North and South Qinling orogenic belts, and the Yangtze craton) of central East China and the study area as a whole. The estimates are based on sampling of 11,451 individual rock samples over an area of 950,000 km 2, from which 905 large composite samples were prepared and analyzed by thirteen methods. Some of the trace elements (i.e., Ag, As, Ge, Mo, Pd, Pt, Sb, Se, Sn, W) have never been subjected to systematic analysis in previous regional crustal composition studies. The middle, lower, and total crust compositions of the tectonic units are also estimated from studies of exposed crustal cross-sections and granulite xenoliths and by correlation of seismic data from eleven regional seismic refraction profiles with lithologies. The proposed granodioritic total crust composition has the following ratios of element pairs exhibiting similar compatibility, that are identical or close to the primitive mantle values: Zr/Hf = 37, Nb/Ta = 17.5, Ba/Th = 87, K/Pb = 0.12 10 4, Rb/Cs = 25, Ba/Rb = 8.94, Sn/Sm = 0.31, Se/Cd = 1.64, La/As = 10.3, Ce/Sb = 271, Pb/Bi = 57, Rb/Tl = 177, Er/Ag = 52, Cu/Au = 3.210 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.

  17. Aerogel/polymer composite materials

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  18. Polyaniline-carbon nanofiber composite by a chemical grafting approach and its supercapacitor application.

    PubMed

    Kotal, Moumita; Thakur, Awalendra K; Bhowmick, Anil K

    2013-09-11

    Unlike conventional routes by van der Waals forces, a facile and novel approach using covalent bonding is established in the present work to synthesize polyaniline (PANI)-grafted carbon nanofiber (CNF) composites as promising supercapacitors. For this purpose, toluenediisocyanate was initially functionalized to carboxylated CNF via amidation followed by reaction with excess aniline to form a urea derivative and residual aniline, which was subsequently polymerized and grafted with a urea derivative. Amidation of CNF (TCNF) and, consequently, the grafting of PANI on TCNF were verified by IR, Raman, 1H NMR, X-ray photoelectron, and UV-visible spectroscopic methods, X-ray diffraction, and thermogravimetric analysis. Morphological analysis revealed uniform distribution of PANI on the surface of TCNF, indicating strong interaction between them. Electrochemical tests of the composite containing 6 wt % TCNF demonstrated efficient capacitance of ∼557 F g(-1) with a capacity retention of 86% of its initial capacitance even after 2000 charge-discharge cycles at a current density of 0.3 A g(-1), suggesting its superiority compared to the materials formed by van der Waals forces. The remarkably enhanced electrochemical performance showed the importance of the phenyl-substituted amide linkage in the development of a π-conjugated structure, which facilitated charge transfer and, consequently, made it attractive for efficient supercapacitors. PMID:23911041

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

    SciTech Connect

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

    2013-09-16

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

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

    NASA Astrophysics Data System (ADS)

    Bharathan, Jayesh Moorkoth

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

  1. Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

    NASA Astrophysics Data System (ADS)

    Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

    2016-01-01

    In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

  2. Multilayer Electroactive Polymer Composite Material

    NASA Technical Reports Server (NTRS)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

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

    PubMed

    Rieder, R; Economou, T; Wnke, H; Turkevich, A; Crisp, J; Brckner, J; Dreibus, G; McSween, H Y

    1997-12-01

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

  4. Method of forming a chemical composition

    DOEpatents

    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)

    2007-10-09

    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.

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

    PubMed

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

    2013-09-15

    In this manuscript, we report the preparation and characterization of sulphosalicylic doped tetraethoxysilane (SATEOS), composite material by sol-gel method as a new ion exchanger for the removal of Ni(II) from aqueous solution. The fine granular material was prepared by acid catalyzed condensation polymerization through sol-gel mechanism in the presence of cationic surfactant. The material has an ion exchange capacity of 0.64 mequiv./g(dry) for sodium ions, 0.60 mequiv./g(dry) for potassium ions, 1.84 mequiv./g(dry) for magnesium ions, 1.08 mequiv./g(dry) for calcium ions and 1.36 mequiv./g(dry) for strontium ions. Its X-ray diffraction studies suggest that it is crystalline in nature. The material has been characterized by SEM, IR, TGA and DTG so as to identify the various functional groups and ion exchange sites present in this material. Quantum chemical computations at DFT/B3LYP/6-311G (d,p) level on model systems were performed to substantiate the structural conclusions based ion instrumental techniques. Investigations into the elution behaviour, ion exchange reversibility and distribution capacities of this material towards certain environmentally hazardous metal ions are also performed. The material shows good chemical stability towards acidic conditions and exhibits fast elution of exchangeable H(+) ions under neutral conditions. This material shows remarkable selectivity for Ni(II) and on the basis of its Kd value (410(2) in 0.01M HClO4) some binary separations of Ni(II) from other metal ions are performed. PMID:23774782

  6. Analysis of moisture content, total oil and fatty acid composition by NIR reflectance spectroscopy: a review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near Infrared (NIR) Reflectance spectroscopy has established itself as an important analytical technique in the field of food and agriculture. It is quicker and easier to use and does not require processing the samples with corrosive chemicals such as acids or hydroxides. However, for a long time t...

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

    SciTech Connect

    Dispenza, C.; Spadaro, G.; Alessi, S.

    2008-08-28

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

  8. Carbon Fibre Composite Materials Produced by Gamma Radiation Induced Curing of Epoxy Resins

    NASA Astrophysics Data System (ADS)

    Dispenza, C.; Alessi, S.; Spadaro, G.

    2008-08-01

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

  9. Evolution of groundwater chemical composition by plagioclase hydrolysis in Norwegian anorthosites

    NASA Astrophysics Data System (ADS)

    Banks, David; Frengstad, Bjørn

    2006-03-01

    The Precambrian Egersund anorthosites exhibit a wide range of groundwater chemical composition (pH 5.40-9.93, Ca 2+ 1.5-41 mg/L, Na + 12.3-103 mg/L). They also exhibit an evolutionary trend, culminating in high pH, Na-rich, low-Ca groundwaters, that is broadly representative of Norwegian crystalline bedrock aquifers in general. Simple PHREEQC modelling of monomineralic plagioclase-CO 2-H 2O systems demonstrates that the evolution of such waters can be explained solely by plagioclase weathering, coupled with calcite precipitation, without invoking cation exchange. Some degree of reaction in open CO 2 systems seems necessary to generate the observed maximum solute concentrations, while subsequent system closure can be invoked to explain high observed pH values. Empirical data provide observations required or predicted by such a model: (i) the presence of secondary calcite in silicate aquifer systems, (ii) the buffering of pH at around 8.0-8.3 by calcite precipitation, (iii) significant soil gas CO 2 concentrations ( PCO 2 > 10 -2 atm) even in poorly vegetated sub-arctic catchments, and (iv) the eventual re-accumulation of calcium in highly evolved, high pH waters.

  10. 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

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection of Environment ENVIRONMENTAL... Phosphate Rock by Origin Origin Total carbon(percent by weight) Central Florida 1.6 North Florida 1.76...

  11. 40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection of Environment ENVIRONMENTAL... Phosphate Rock by Origin Origin Total carbon(percent by weight) Central Florida 1.6 North Florida 1.76...

  12. 40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection of Environment ENVIRONMENTAL... Phosphate Rock by Origin Origin Total carbon(percent by weight) Central Florida 1.6 North Florida 1.76...

  13. 40 CFR Table Z-1 to Subpart Z of... - Default Chemical Composition of Phosphate Rock by Origin

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Default Chemical Composition of Phosphate Rock by Origin Z Table Z-1 to Subpart Z of Part 98 Protection of Environment ENVIRONMENTAL... Phosphate Rock by Origin Origin Total carbon(percent by weight) Central Florida 1.6 North Florida 1.76...

  14. Surface Chemical Compositions and Dispersity of Starch Nanocrystals Formed by Sulfuric and Hydrochloric Acid Hydrolysis

    PubMed Central

    Wei, Benxi; Xu, Xueming; Jin, Zhengyu; Tian, Yaoqi

    2014-01-01

    Surface chemical compositions of starch nanocrystals (SNC) prepared using sulfuric acid (H2SO4) and hydrochloric acid (HCl) hydrolysis were analyzed by X-ray photoelectron spectroscopy (XPS) and FT-IR. The results showed that carboxyl groups and sulfate esters were presented in SNC after hydrolysis with H2SO4, while no sulfate esters were detected in SNC during HCl-hydrolysis. TEM results showed that, compared to H2SO4-hydrolyzed sample, a wider size distribution of SNC prepared by HCl-hydrolysis were observed. Zeta-potentials were ?23.1 and ?5.02 mV for H2SO4- and HCl-hydrolyzed SNC suspensions at pH 6.5, respectively. Nevertheless, the zeta-potential values decreased to ?32.3 and ?10.2 mV as the dispersion pH was adjusted to 10.6. After placed 48 h at pH 10.6, zeta-potential increased to ?24.1 mV for H2SO4-hydrolyzed SNC, while no change was detected for HCl-hydrolyzed one. The higher zeta-potential and relative small particle distribution of SNC caused more stable suspensions compared to HCl-hydrolyzed sample. PMID:24586246

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

    NASA Astrophysics Data System (ADS)

    Jimnez, Vicente; Ramrez-Lucas, Ana; Snchez, Paula; Valverde, Jos Lus; Romero, Amaya

    2012-01-01

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

  16. Particle Morphology and Elemental Composition of Smoke Generated by Overheating Common Spacecraft Materials

    NASA Technical Reports Server (NTRS)

    Meyer, Marit E.

    2015-01-01

    Fire safety in the indoor spacecraft environment is concerned with a unique set of fuels which are designed to not combust. Unlike terrestrial flaming fires, which often can consume an abundance of wood, paper and cloth, spacecraft fires are expected to be generated from overheating electronics consisting of flame resistant materials. Therefore, NASA prioritizes fire characterization research for these fuels undergoing oxidative pyrolysis in order to improve spacecraft fire detector design. A thermal precipitator designed and built for spacecraft fire safety test campaigns at the NASA White Sands Test Facility (WSTF) successfully collected an abundance of smoke particles from oxidative pyrolysis. A thorough microscopic characterization has been performed for ten types of smoke from common spacecraft materials or mixed materials heated at multiple temperatures using the following techniques: SEM, TEM, high resolution TEM, high resolution STEM and EDS. Resulting smoke particle morphologies and elemental compositions have been observed which are consistent with known thermal decomposition mechanisms in the literature and chemical make-up of the spacecraft fuels. Some conclusions about particle formation mechanisms are explored based on images of the microstructure of Teflon smoke particles and tar ball-like particles from Nomex fabric smoke.

  17. Dense, finely, grained composite materials

    DOEpatents

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

    1990-01-01

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

  18. Advanced composite materials and processes

    NASA Technical Reports Server (NTRS)

    Baucom, Robert M.

    1991-01-01

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

  19. Composite Materials for Thermal Energy Storage: Enhancing Performance through Microstructures

    PubMed Central

    Ge, Zhiwei; Ye, Feng; Ding, Yulong

    2014-01-01

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

  20. Chemical composition of selected edible nut seeds.

    PubMed

    Venkatachalam, Mahesh; Sathe, Shridhar K

    2006-06-28

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

  1. The chemical composition of ancient atmospheres: A model study constrained by ice core data

    NASA Astrophysics Data System (ADS)

    Martinerie, Patricia; Brasseur, Guy P.; Granier, Claire

    1995-07-01

    A coupled chemistry radiation transport two-dimensional model of the lower and middle atmosphere was adapted to study the chemical composition of the atmosphere at preindustrial time and last glacial maximum (LGM). The model was constrained by trace gas concentrations (CO2, CH4, and N2O) inferred from polar ice core records. The formulation of tropospheric dynamics and chemistry was improved in order to more accurately simulate the transport and the oxidation processes below the tropopause. Our objectives are to infer the changes in middle-atmosphere temperature, ozone layer, and oxidation capacity of the atmosphere (e.g., methane lifetime) over the last 18,000 years. A middle-atmosphere cooling was obtained between LGM and preindustrial Holocene (PIH) as well as between PIH and present time. This is mainly due to changes in the CO2 and chlorofluorocarbon (CFC) concentrations, respectively. CFCs are also the main contributors to the middle-atmosphere ozone decrease since PIH. Between LGM and PIH the compensating effects of CO2 and N2O lead to little variation in stratospheric ozone. A 17% decrease in tropospheric OH was obtained between LGM and PIH, whereas the model provides a 6% OH increase since PIH. The corresponding changes in the methane sink are too small to have played a dominant role in the past methane concentration changes. Our model derived methane emissions for LGM, PIH, and present time are in good agreement with methane sources evaluated during these three periods.

  2. Chemical compositions by using LC-MS/MS and GC-MS and biological activities of Sedum sediforme (Jacq.) Pau.

    PubMed

    Erta?, Abdulselam; Bo?a, Mehmet; Y?lmaz, Mustafa Abdullah; Ye?il, Yeter; Ha?imi, Nesrin; Kaya, Meryem ?eyda; Temel, Hamdi; Kolak, Ufuk

    2014-05-21

    In this research, the chemical composition and biological activities of various extracts obtained from whole parts of Sedum sediforme (Jacq.) Pau were compared. The amounts of total phenolic and flavonoid components in crude extracts were determined by expression as pyrocatechol and quercetin equivalents, respectively. All of the extracts (petroleum ether, acetone, methanol, and water) obtained from S. sediforme showed strong antioxidant activity in four tested methods. Particularly, the IC50 values of the methanol extract, which was the richest in terms of total phenolic and flavonoid contents, were found to be lower than those of ?-tocopherol and BHT in ?-carotene bleaching (9.78 0.06 ?g/mL), DPPH free radical scavenging (9.07 0.07 ?g/mL), and ABTS cation radical scavenging (5.87 0.03 ?g/mL) methods. Furthermore, the methanol extract of S. sediforme showed higher inhibition activity than galanthamine against acetyl- and butyryl-cholinesterase enzymes. Also, acetone and methanol extracts exhibited moderate antimicrobial activity against Candida albicans. The main constituents of fatty acid and essential oil were identified as palmitic acid (C16:0) (28.8%) and ?-selinene (20.4%), respectively, by GC-MS. In the methanol extract of S. sediforme, quercetin, rutin, naringenin, and protocatechuic, p-coumaric, caffeic, and chlorogenic acids were detected and quantified by LC-MS/MS. Results of the current study showed that the methanol extract of S. sediforme may also be used as a food supplement. PMID:24773044

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    SciTech Connect

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

    1980-12-01

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

  5. Aerosol chemical composition in cloud events by high resolution time-of-flight aerosol mass spectrometry.

    PubMed

    Hao, Liqing; Romakkaniemi, Sami; Kortelainen, Aki; Jaatinen, Antti; Portin, Harri; Miettinen, Pasi; Komppula, Mika; Leskinen, Ari; Virtanen, Annele; Smith, James N; Sueper, Donna; Worsnop, Douglas R; Lehtinen, Kari E J; Laaksonen, Ari

    2013-03-19

    This study presents results of direct observations of aerosol chemical composition in clouds. A high-resolution time-of-flight aerosol mass spectrometer was used to make measurements of cloud interstitial particles (INT) and mixed cloud interstitial and droplet residual particles (TOT). The differences between these two are the cloud droplet residuals (RES). Positive matrix factorization analysis of high-resolution mass spectral data sets and theoretical calculations were performed to yield distributions of chemical composition of the INT and RES particles. We observed that less oxidized hydrocarbon-like organic aerosols (HOA) were mainly distributed into the INT particles, whereas more oxidized low-volatile oxygenated OA (LVOOA) mainly in the RES particles. Nitrates existed as organic nitrate and in chemical form of NH(4)NO(3). Organic nitrates accounted for 45% of total nitrates in the INT particles, in clear contrast to 26% in the RES particles. Meanwhile, sulfates coexist in forms of acidic NH(4)HSO(4) and neutralized (NH(4))(2)SO(4). Acidic sulfate made up 64.8% of total sulfates in the INT particles, much higher than 10.7% in the RES particles. The results indicate a possible joint effect of activation ability of aerosol particles, cloud processing, and particle size effects on cloud formation. PMID:23419193

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  7. Investigation of the chemical vapor deposition of silicon carbide from tetramethylsilane by in situ temperature and gas composition measurements

    SciTech Connect

    Herlin, N.; Lefebvre, M.; Pealat, M.; Perrin, J.

    1992-08-20

    The chemical vapor deposition (CVD) of silicon carbide (SiC) from tetramethylsilane Si(CH{sub 3}){sub 4} (TMS) on a graphite susceptor at 1200-1500 K is studied in a low pressure ({approx}100 Pa) cold-wall reactor under laminar flow conditions. In addition to material characterization (electron microscopy and chemical analysis), the gas-phase temperature distribution and composition are investigated by combining several in situ and ex situ diagnostics. Coherent anti-Stokes Raman spectroscopy (CARS) on TMS and H{sub 2} (produced from TMS decomposition) in the hot zone of the reactor gives the rotational temperature distribution of the molecules and their concentrations. Within a few mean free paths from the surface, the H{sub 2} gas temperature is lower than the surface temperature. This is due to nonunity accommodation coefficient {alpha} of H{sub 2} on SiC. A simple analytical model yields {alpha} = 0.05 for H{sub 2} on SiC. Using gas transport coefficients and the experimental value of {alpha} for H{sub 2}, a two-dimensional numerical code is used to compute the gas flow and temperature profiles in the reactor. The increase of the H{sub 2} concentration and the decrease of TMS concentration close to the surface reveals that gas-phase pyrolysis of TMS occurs within a few millimeters from the hot surface. The gas composition at the outlet of the reactor is analyzed by mass spectrometry and IR absorption spectroscopy. The global gas conversion and material balance between deposited SiC, powders, and exhaust gases is obtained Si atoms of TMS molecules are mostly converted into solid SiC and powders. In the gaseous products a small fraction of trimethylsilane SiH(CH{sub 3}){sub 3} is detected. Other gases in decreasing order of importance are H{sub 2}, CH{sub 4}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 2}. These results are compared with predictions of some thermodynamic models and chemical mechanisms reported in the literature. 42 refs., 15 figs., 5 tabs.

  8. Fiber composite materials technology development

    SciTech Connect

    Chiao, T.T.

    1980-10-23

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

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

    PubMed

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

    2012-01-15

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

  10. NASA technology utilization survey on composite materials

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  11. On-line prediction of chemical composition of semi-frozen ground beef by non-invasive NIR spectroscopy.

    PubMed

    Tgersen, G; Arnesen, J F; Nilsen, B N; Hildrum, K I

    2003-04-01

    The chemical composition of industrial scale batches of frozen beef was measured on-line during grinding by near infrared (NIR) reflectance spectroscopy. The MM55E filter based non-contact NIR instrument was mounted at the outlet of a meat grinder, and the fat, moisture and protein contents determined from the average of each filter reading throughout the grinding of the batch. The filters were selected from full spectra measurements to be as insensitive to water crystallization as possible. For on-line calibration and prediction, 55 beef batches of 400-800 kg in the range of 7.66-22.91% fat, 59.36-71.48% moisture, and 17.04-20.76% protein, were ground through 4 or 13 mm hole plates. The regression results, presented as root mean square error of cross validation (RMSECV) were between 0.48 and 1.11% for fat, 0.43 and 0.97% for moisture and 0.41 and 0.47% for protein. PMID:22062522

  12. Failure Study of Composite Materials by the Yeh-Stratton Criterion

    NASA Technical Reports Server (NTRS)

    Yeh, Hsien-Yang; Richards, W. Lance

    1997-01-01

    The newly developed Yeh-Stratton (Y-S) Strength Criterion was used to study the failure of composite materials with central holes and normal cracks. To evaluate the interaction parameters for the Y-S failure theory, it is necessary to perform several biaxial loading tests. However, it is indisputable that the inhomogeneous and anisotropic nature of composite materials have made their own contribution to the complication of the biaxial testing problem. To avoid the difficulties of performing many biaxial tests and still consider the effects of the interaction term in the Y-S Criterion, a simple modification of the Y-S Criterion was developed. The preliminary predictions by the modified Y-S Criterion were relatively conservative compared to the testing data. Thus, the modified Y-S Criterion could be used as a design tool. To further understand the composite failure problem, an investigation of the damage zone in front of the crack tip coupled with the Y-S Criterion is imperative.

  13. Carbon fiber content measurement in composite

    NASA Astrophysics Data System (ADS)

    Wang, Qiushi

    Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40C min--1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and Malek methods. The activation energy (Ea) of the solid-state process is determined to be 202 kJ mol--1 in an oxidative atmosphere using Kissinger's method, which is 10-15 kJ mol--1 more than the results calculated in a nitrogen atmosphere. The value of the activation energy obtained using Ozawa-Flynn methods is in agreement with that using the Kissinger method. Different degradation mechanisms are used to compare with this value. Based on the analytical result, the actual thermal degradation mechanism of the CPPS is a Dn deceleration type. The carbonization temperature range of the CPPS is the same as pure PPS resin.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  15. Determination of chemical composition of siderite in concretions by wavelength-dispersive X-ray spectrometry following selective dissolution.

    PubMed

    Sitko, Rafa?; Zawisza, Beata; Krzykawski, Tomasz; Malicka, Ewa

    2009-01-15

    Determination of chemical composition of siderite (Fe, Me)CO(3) (where Me=Mg, Ca, Mn) present in siderite concretion is developed. An accurate and precise determination of Mg, Ca, Mn and Fe in siderite required complete separation of this mineral from other materials, e.g. calcite, quartz. For this purpose, selective dissolution in acetic acid (HAc) was applied. HAc concentration from 0.1 to 1 mol L(-1) and extraction time from 0.5 to 8h were investigated. In each step of investigation of selective dissolution, the X-ray diffraction measurements (XRD) of the residues was performed and also calcium (complexometric titration) and iron (XRF) in solution were determined. HAc of concentration 0.25 mol L(-1) and extraction time of 2h was adopted for siderite separation because in these conditions the siderite was not dissolved and, simultaneously, calcite was completely dissolved. In the next step, the nondissolved sample was digested in hydrochloric acid. The solution of the separated siderite was pipetted onto membrane filter and Mg, Ca, Mn and Fe were determined by wavelength-dispersive X-ray fluorescence (WDXRF) spectrometry. The calibration was performed using 11 certified reference materials of iron ores. Matrix effects were corrected using empirical coefficient model for intermediate-thickness samples. PMID:19064098

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

    SciTech Connect

    Landais, P.; Rochdi, A. ); Largeau, C.; Derenne, S. )

    1993-06-01

    Four Permian to Carboniferous torbanites of various geographical origins were examined by transmission micro-FTIR spectroscopy on doubly polished thin sections (10--25 [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.

  17. Nondestructive evaluation of composite materials by pulsed time domain methods in imbedded optical fibers

    NASA Technical Reports Server (NTRS)

    Claus, R. O.; Bennett, K. D.; Jackson, B. S.

    1986-01-01

    The application of fiber-optical time domain reflectometry (OTDR) to nondestructive quantitative measurements of distributed internal strain in graphite-epoxy composites, using optical fiber waveguides imbedded between plies, is discussed. The basic OTDR measurement system is described, together with the methods used to imbed optical fibers within composites. Measurement results, system limitations, and the effect of the imbedded fiber on the integrity of the host composite material are considered.

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

    NASA Technical Reports Server (NTRS)

    Chait, Richard

    1992-01-01

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

  19. Fabrication and evaluation of low fiber content alumina fiber/aluminum composites

    NASA Technical Reports Server (NTRS)

    Hack, J. E.; Strempek, G. C.

    1980-01-01

    The mechanical fabrication of low volume percent fiber, polycrystalline alumina fiber reinforced aluminum composites was accomplished. Wire preform material was prepared by liquid-metal infiltration of alumina fiber bundles. The wires were subsequently encapsulated with aluminum foil and fabricated into bulk composite material by hot-drawing. Extensive mechanical, thermal and chemical testing was conducted on preform and bulk material to develop a process and material data base. In addition, a preliminary investigation of mechanical forming of bulk alumina fiber reinforced aluminum composite material was conducted.

  20. Chemical vapor infiltration of non-oxide ceramic matrix composites

    SciTech Connect

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

    1993-12-31

    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.

  1. Characterization of the failure process in composite materials by the Fiber Bundle Model

    NASA Astrophysics Data System (ADS)

    Hader, A.; Achik, I.; Lahyani, A.; Sbiaai, K.; Boughaleb, Y.

    2014-07-01

    Our aim in this paper is to investigate the time distribution of the monomer intact fiber of a bundle model of fibers subject to a constant external load. Breaking process is created by thermally induced stress fluctuations followed by load redistribution with the local load-sharing rule (LLS) which subsequently leads to an avalanche of breakings. The results showed that the maximum number of the intact fiber monomer (MNIFM) was observed at time t1 proportional to the materials failure time tf independently of the temperature value (t1≈ 1/3 tf). So, this parameter can characterize clearly the avalanche phenomenon observed in the failure process of the composite materials. Moreover, we have found that MNIFM presents a Gaussian variation with the applied load and exhibits a power law with the size of the system. The MNIFM temperature dependence was also investigated in this study.

  2. Predicting Properties Of Composite Materials

    NASA Technical Reports Server (NTRS)

    Naik, Rajiv A.

    1994-01-01

    Micromechanical Combined Stress Analysis (MICSTRAN) computer code provides materials engineers with easy-to-use personal-computer-based software tool to calculate overall properties of composite, given properties of fibers and matrix. Computes overall thermoelastic parameters and stresses by micromechanical analysis. Written in FORTRAN 77.

  3. Chemical processing of lunar materials

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  4. Composite containing coated fibrous material

    SciTech Connect

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

    1989-12-26

    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.

  5. Standardization of allergen extracts by inhibition of RAST, skin test, and chemical composition.

    PubMed

    Turner, K J; Stewart, G A; Sharp, A H; Czarny, D

    1980-07-01

    Five allergen extracts of Dermatophagoides pteronyssinus, Lolium perenne, Alternaria tenuis, Aspergillus fumigatus and Cladosporium herbarum, obtained from four different manufacturers, were examined by inhibition of RAST, content of protein and carbohydrate, contents of phosphorylcholine (Pc) and tridacnin reactive components, and by skin test. Inhibition of RAST was used as a primary method for establishing allergenic potency and demonstrated wide variations for each preparation supplied by the different manufacturers. The extracts also varied widely in protein and carbohydrate content and in the ratio of these parameters, indicating internal heterogeneity. Pc content was significantly related to RAST potency for extracts of A. fumigatus and A. tenuis, suggesting that Pc content may be used as a primary standarization procedure for these extracts. Skin test reactions undertaken at a single concentration did not show any significant variation in weal size between preparations of a given allergen extract. However, of particular importance to practising clinicians is the finding that varying numbers of patients showed negative skin reactions to one preparation of a particular allergen yet were positive to the corresponding preparations supplied by the other companies. PMID:7004662

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

    SciTech Connect

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

    1984-05-01

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

  7. 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...

  8. Molar mass, chemical-composition, and functionality-type distributions of poly(2-oxazoline)s revealed by a variety of separation techniques.

    PubMed

    Chojnacka, Aleksandra; Kempe, Kristian; van de Ven, Henrik C; Englert, Christoph; Hoogenboom, Richard; Schubert, Ulrich S; Janssen, Hans-Gerd; Schoenmakers, Peter

    2012-11-23

    Detailed characterization of synthetic polymers often required multiple advanced separation technologies since the various molecular distributions present, e.g. polymer molar mass, chemical composition, functionality distributions, etc. are generally mutually dependent. The complexity of polymeric materials necessitates the use of a variety of analytical methods, either in conjunction or in integrated ("hyphenated") systems. Poly(2-oxazoline) homo- and copolymers with two different side groups rendering the systems hydrophobic, i.e. phenyl and dec-9-enyl substituents, synthesized by living cationic ring-opening polymerization, were investigated. The average chemical composition obtained by pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) corresponded well with the theoretical composition. The chemical-composition distribution was studied with gradient elution liquid chromatography (GELC) using water and tetrahydrofuran as mobile-phase components. Statistical copolymer samples - in contrast to their block copolymer analogues - revealed two well-separated peaks in GELC. By combining GELC with size-exclusion chromatography (SEC) it was confirmed that the GELC separation was not based on differences in the molar mass. A more likely explanation of the GELC results is the presence of an ionic fraction in the samples of statistical copolymers resulting from either chain-transfer reactions or termination by addition of water. This hypothesis was confirmed with capillary electrophoresis. PMID:23068763

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

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

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

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

    SciTech Connect

    Todd, R.I.; Borsa, C.; Derby, B.; Bourke, M.A.M.

    1994-07-01

    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.

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

    PubMed Central

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

    2014-01-01

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

  12. Composition and microstructure of zirconium and hafnium germanates obtained by different chemical routes

    SciTech Connect

    Utkin, A.V. Prokip, V.E.; Baklanova, N.I.

    2014-01-15

    The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. The products were characterized using high-temperature X-ray diffraction analysis (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and thermal (TG/DTA) analysis. To investigate the phase composition and stoichiometry of compounds the unit cell parameters were refined by full-profile Rietveld XRD analysis. The morphology of products and its evolution during high-temperature treatment was examined by SEM analysis. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. The ceramic route requires a multi-stage high-temperature treatment to obtain zirconium and hafnium germanates of 95% purity or more. Also, there are strong diffusion limitations to obtain hafnium germanate Hf{sub 3}GeO{sub 8} by ceramic route. On the contrary, the co-precipitation route leads to the formation of nanocrystalline single phase germanates of stoichiometric composition at a relatively low temperatures (less than 1000 C). The results of quantitative XRD analysis showed the hafnium germanates are stoichiometric compounds in contrast to zirconium germanates that form a set of solid solutions. This distinction may be related to the difference in the ion radii of Zr and Hf. - Graphical abstract: The phase composition and morphology of zirconium and hafnium germanates synthesized by ceramic and co-precipitation routes were studied. It was stated that there is the strong dependence of the phase composition and morphology of products on the preparation route. Display Omitted - Highlights: Zr and Hf germanates were synthesized by ceramic and co-precipitation routes. The morphology of products depends on the synthesis parameters. Zirconium germanates forms a set of solid solutions. Hafnium germanates are stoichiometric compounds.

  13. Joining of polymer composite materials

    SciTech Connect

    Magness, F.H.

    1990-11-01

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

  14. Durability of aircraft composite materials

    NASA Technical Reports Server (NTRS)

    Dextern, H. B.

    1982-01-01

    Confidence in the long term durability of advanced composites is developed through a series of flight service programs. Service experience is obtained by installing secondary and primary composite components on commercial and military transport aircraft and helicopters. Included are spoilers, rudders, elevators, ailerons, fairings and wing boxes on transport aircraft and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on helicopters. Materials included in the evaluation are boron/epoxy, Kevlar/epoxy, graphite/epoxy and boron/aluminum. Inspection, maintenance, and repair results for the components in service are reported. The effects of long term exposure to laboratory, flight, and outdoor environmental conditions are reported for various composite materials. Included are effects of moisture absorption, ultraviolet radiation, and aircraft fuels and fluids.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    DOEpatents

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

    1984-09-07

    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.

  17. Mechanical properties of composite materials

    NASA Technical Reports Server (NTRS)

    Thornton, H. Richard; Cornwell, L. R.

    1993-01-01

    A composite material incorporates high strength, high modulus fibers in a matrix (polymer, metal, or ceramic). The fibers may be oriented in a manner to give varying in-plane properties (longitudinal, transverse-stress, strain, and modulus of elasticity). The lay-up of the composite laminates is such that a center line of symmetry and no bending moment exist through the thickness. The laminates are tabbed, with either aluminum or fiberglass, and are ready for tensile testing. The determination of the tensile properties of resin matrix composites, reinforced by continuous fibers, is outlined in ASTM standard D 3039, Tensile Properties of Oriented Fiber Composites. The tabbed flat tensile coupons are placed into the grips of a tensile machine and load-deformation curves plotted. The load-deformation data are translated into stress-strain curves for determination of mechanical properties (ultimate tensile strength and modulus of elasticity).

  18. Information Content of Turbulent Chemical Plumes

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Roberts, P. J. W.; Rahman, S.; Dasi, L. P.

    1999-11-01

    The rapid decrease in concentration contaminants released into the natural environment due to turbulent diffusion has traditionally been modeled based on time-averaged quantities. In contrast to the time-averaged concentration characteristics, the instantaneous characteristics and information content are poorly understood. Instantaneous peak levels are important in many contexts, including the impact of contaminants on organisms and the local ecosystem. The current work is motivated by the need to understand how aquatic organisms, such as blue crabs, search for and locate turbulent chemical odor plume sources. A fundamental question is what information is available to an animal or observer indicating its relative position to the plume source. In this study, the chemical plume is released iso-kinetically into a fully-developed, uniform open channel flow at 50 mm/s. Instantaneous concentration and velocity fields are simultaneously measured using planar laser induced fluorescence (PLIF) and digital particle tracking velocimetry (DPTV), respectively. In addition to the mean and variance, quantities of interest include intermittency, the temporal rise slope of chemical concentration and spatial correlations.

  19. Chemical compositions, methods of making the chemical compositions, and structures made from the chemical compositions

    DOEpatents

    Yang, Lei; Cheng, Zhe; Liu, Ze; Liu, Meilin

    2015-01-13

    Embodiments of the present disclosure include chemical compositions, structures, anodes, cathodes, electrolytes for solid oxide fuel cells, solid oxide fuel cells, fuel cells, fuel cell membranes, separation membranes, catalytic membranes, sensors, coatings for electrolytes, electrodes, membranes, and catalysts, and the like, are disclosed.

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

    SciTech Connect

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

    2011-12-31

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

  1. Method to fabricate layered material compositions

    DOEpatents

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

    2002-01-01

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

  2. Method to fabricate layered material compositions

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu

    2004-11-02

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

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

    SciTech Connect

    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.

    2011-01-18

    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.

  4. Chemical erosion of first-wall materials by atomic hydrogen at high temperatures

    NASA Astrophysics Data System (ADS)

    Ashby, C. I. H.

    The chemical erosion of C, TiB2, and TiC by reaction with H was studied from 420 to 1540 K using H pressures characteristic of fusion devices. For graphite, erosion yields range from 2.0 to 7.4 C/H over this temperature range. A change in the gas phase product distribution is observed as a function of temperature and reaction time. Methane is most abundant at low temperatures and short reaction times, while C2 and C3 species increase in abundance at higher temperatures and after extended reaction times. For C-rich TiC, initial behavior is similar to graphite, but the time evolution of gas phase products differs. TiB2 shows no evidence of reaction below 1300 K and lower erosion yields than graphite at higher temperatures. The superior erosion resistance of TiB2 suggests that it may be a better candidate material than graphite for fusion applications requiring refractory low-Z materials.

  5. Chemical composition and temperature influence on honey texture properties.

    PubMed

    Oroian, Mircea; Paduret, Sergiu; Amariei, Sonia; Gutt, Gheorghe

    2016-01-01

    The aim of this study is to evaluate the chemical composition and temperatures (20, 30, 40, 50 and 60 °C) influence on the honey texture parameters (hardness, viscosity, adhesion, cohesiveness, springiness, gumminess and chewiness). The honeys analyzed respect the European regulation in terms of moisture content and inverted sugar concentration. The texture parameters are influenced negatively by the moisture content, and positively by the °Brix concentration. The texture parameters modelling have been made using the artificial neural network and the polynomial model. The polynomial model predicted better the texture parameters than the artificial neural network. PMID:26787962

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

    PubMed

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

    2011-10-01

    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 Lys. Moreover, in BPH deep deficits of Met, Cys, Thr and other amino acids were found. The experiment comprised 7 dietary treatments: SDBP, SDBC, and BPH, each at an inclusion rate of 20 or 40?g/kg diet, plus a control. The addition of 20 or 40?g/kg of the analysed meals into feeds for very young chickens (1-28?d post hatch) significantly decreased the body weight (BW) of birds. Only the treatments with 40?g/kg of SDBP and SDBC showed no significant difference in BW as compared with the control. There were no significant differences between treatments and type of meal for feed intake, haematocrit and haemoglobin concentrations in blood. Addition of bone protein and blood cell meals to feed decreased the IgG concentration in blood and caused shortening of the femur and tibia bones. However, changes in the mineral composition of bones were not significantly affected by the type of meal used. The blood by-products, which are rich in microelements, improved retention of Ca and Cu only. In comparison to control chickens, significantly better accretion of these minerals was found in treatments containing 20?g/kg of SDBP or 40?g/kg of SDBC. Great variability in apparent ileal amino acid digestibility in chickens was determined. In this respect, some significant differences related to the type of meal fed were confirmed for Asp, Pro, Val, Tyr and His. In general, the apparent ileal digestibility of amino acids was about 2-3 percentage units better in chickens fed on diets containing the animal by products than in control birds. PMID:22029787

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

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  8. Nonlinear Dynamic Properties of Layered Composite Materials

    SciTech Connect

    Andrianov, Igor V.; Topol, Heiko; Weichert, Dieter; Danishevs'kyy, Vladyslav V.

    2010-09-30

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

  9. Prediction of Local Ultimate Strain and Toughness of Trabecular Bone Tissue by Raman Material Composition Analysis

    PubMed Central

    Stüssi, Edgar; Müller, Ralph

    2015-01-01

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

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

    SciTech Connect

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

    1983-07-01

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

  11. Chemical modifiers in arsenic determination in biological materials by tungsten coil electrothermal atomic absorption spectrometry.

    PubMed

    Bruhn, C G; Huerta, V N; Neira, J Y

    2004-01-01

    Palladium, iridium, and rhodium are evaluated as possible chemical modifiers in the determination of As in digest solutions of biological materials (human hair and clam) by tungsten coil electrothermal atomic absorption spectrophotometry (TCA-AAS). The modifier in solution was applied onto the coil and thermally pre-reduced; the pre-reduction conditions, the amount of modifier, and the thermal program were optimized. Palladium was not satisfactory, whereas Ir and Rh were effective modifiers and rendered better relative sensitivity for As by a factor of 1.4 and 1.9, respectively compared to the case without modifier. Upon optimization of thermal conditions for As in pre-reduced Ir (2.0 microg) and Rh (2.0 microg) modifiers and in the digest solutions of the study matrices, Rh (2.0 microg) was more effective modifier and was selected as such. The mean within-day repeatability was 2.8% in consecutive measurements (25-100 microg L(-1)) (3 cycles, each of n=6) and confirmed good short-term stability of the absorbance measurements. The mean reproducibility was 4.4% (n=20 in a 3-day period) and the detection limit (3 sigmablank/slope) was 29 pg (n=15). The useful coil lifetime in Rh modifier was extended to 300-400 firings. Validation was by determination of As in the certified reference material (CRM) of "Oyster tissue" solution with a percentage relative error (Erel%) of 2% and percentage relative standard deviation (RSD%) of 3% (n=4), and by analytical recovery of As spiked in CRM of human hair [94 +/- 8% (n=4)]. The methodology is simple, fast (sample readout frequency 21 h(-1)), reliable, of low cost, and was applied to the determination of As in hair samples of exposed and unexposed workers. PMID:14598009

  12. Asymmetric Dielectric Elastomer Composite Material

    NASA Technical Reports Server (NTRS)

    Stewart, Brian K. (Inventor)

    2014-01-01

    Embodiments of the invention provide a dielectric elastomer composite material comprising a plurality of elastomer-coated electrodes arranged in an assembly. Embodiments of the invention provide improved force output over prior DEs by producing thinner spacing between electrode surfaces. This is accomplished by coating electrodes directly with uncured elastomer in liquid form and then assembling a finished component (which may be termed an actuator) from coated electrode components.

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

    SciTech Connect

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

    2010-06-23

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

  14. Chemical composition and tissue energy density of the cuttlefish (Sepia apama) and its assimilation efficiency by Diomedea albatrosses.

    PubMed

    Battam, H; Richardson, M; Watson, A W T; Buttemer, W A

    2010-11-01

    The cuttlefish Sepia apama Gray (Mollusca: Cephalopoda) is a seasonally abundant food resource exploited annually by moulting albatrosses throughout winter and early spring in the coastal waters of New South Wales, Australia. To assess its nutritional value as albatross forage, we analysed S. apama for water, lipid protein, ash contents, energy density and amino acid composition. Because albatrosses consistently consume S. apama parts preferentially in the order of head, viscera and mantle, we analysed these sections separately, but did not identify any nutritional basis for this selective feeding behaviour. The gross energy value of S. apama bodies was 20.9 kJ/g dry mass, but their high water content (>83%; cf <70% for fish) results in a relatively low energy density of 3.53 kJ/g. This may contribute to a need to take large meals, which subsequently degrade flight performance. Protein content was typically >75% dry mass, whereas fat content was only about 1%. Albatrosses feed on many species of cephalopods and teleost fish, and we found the amino acid composition of S. apama to be comparable to a range of species within these taxa. We used S. apama exclusively in feeding trials to estimate the energy assimilation efficiency for Diomedea albatrosses. We estimated their nitrogen-corrected apparent energy assimilation efficiency for consuming this prey to be 81.82 0.72% and nitrogen retention as 2.90 0.11 g N kg(-1) d(-1). Although S. apama has a high water content and relatively low energy density, its protein composition is otherwise comparable to other albatross prey species. Consequently, the large size and seasonal abundance of this prey should ensure that albatrosses remain replete and adequately nourished on this forage while undergoing moult. PMID:20640855

  15. Composite structural materials

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-08-01

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

  17. [Nitrogen and chemical oxygen demand burden of waste water caused by trout raising influenced by the protein content of the feed].

    PubMed

    Schuster, C; Stelz, H; Schmitz-Schlang, O

    1992-12-01

    A possibility was shown, how to quantify the water content of nitrogen and COD (Chemical Oxygen Demand) from intensive fish production, independent of flow rate and feeding time. The nitrogen excretion could be reduced 50% by feeding a protein reduced fish feed (A: 38.4% XP) compared with an fish feed B contending 47.9% protein (XP). The excretion-compartments were evaluated with the waste water parameter COD. Doing this, it could be shown that the COD input by feed A is reduced 20% in opposite to feed B. Further more the separation of fish faeces would achieve an COD reduction from about 50% to 70%. PMID:1289047

  18. Flame-Resistant Composite Materials For Structural Members

    NASA Technical Reports Server (NTRS)

    Spears, Richard K.

    1995-01-01

    Matrix-fiber composite materials developed for structural members occasionally exposed to hot, corrosive gases. Integral ceramic fabric surface layer essential for resistance to flames and chemicals. Endures high temperature, impedes flame from penetrating to interior, inhibits diffusion of oxygen to interior where it degrades matrix resin, resists attack by chemicals, helps resist erosion, and provides additional strength. In original intended application, composite members replace steel structural members of rocket-launching structures that deteriorate under combined influences of atmosphere, spilled propellants, and rocket exhaust. Composites also attractive for other applications in which corrosion- and fire-resistant structural members needed.

  19. Zirconia/alumina functionally gradiented composites by electrophoretic deposition techniques

    SciTech Connect

    Sarkar, P.; Huang, Xuening; Nicholson, P.S. . Dept. of Materials Science and Engineering)

    1993-04-01

    Continuous variation of composition, and thus of physical property, is characteristic of a functionally gradiented material (FGM). Such composite find applications in extreme thermal shielding, the joining of ceramics to metals, optical/electronic functions, and biomaterial implant development. FGMs have been synthesized by chemical vapor deposition (CVD), plasma spraying, self-propagating high-temperature synthesis, and green forming followed by sintering. An electrophoretic deposition and sintering route was used to prepare YSZ/Al[sub 2]O[sub 3] composites with a compositional gradient. The YSZ content was continuously decreased from the YSZ-rich surface to the Al[sub 2]O[sub 3]-rich surface. Microstructural and Vickers hardness (16--24 GPa) evidence tracked the compositional development, and the indentation fracture toughness was found to vary across the section (10--3 MPa[center dot]m[sup 1/2]).

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

    PubMed

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

    2011-02-01

    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 12mg/100g where as in pink aril powder 62 and 16mg/100g, respectively. The anthocyanin content in pink powder decreased from 50.5 to 11.2 and 14.1mg/100g 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

  1. Effects of activated carbon characteristics on the electrosorption capacity of titanium dioxide/activated carbon composite electrode materials prepared by a microwave-assisted ionothermal synthesis method.

    PubMed

    Liu, Po-I; Chung, Li-Ching; Ho, Chia-Hua; Shao, Hsin; Liang, Teh-Ming; Horng, Ren-Yang; Chang, Min-Chao; Ma, Chen-Chi M

    2015-05-15

    Titanium dioxide (TiO2)/ activated carbon (AC) composite materials, as capacitive deionization electrodes, were prepared by a two-step microwave-assisted ionothermal synthesis method. The electrosorption capacity of the composite electrodes was studied and the effects of AC characteristics were explored. These effects were investigated by multiple analytical techniques, including X-ray photoelectron spectroscopy, thermogravimetry analysis and electrochemical impedance spectroscopy, etc. The experimental results indicated that the electrosorption capacity of the TiO2/AC composite electrode is dependent on the characteristics of AC including the pore structure and the surface property. An enhancement in electrosorption capacity was observed for the TiO2/AC composite electrode prepared from the AC with higher mesopore content and less hydrophilic surface. This enhancement is due to the deposition of anatase TiO2 with suitable amount of Ti-OH. On the other hand, a decline in electrosorption capacity was observed for the TiO2/AC composite electrode prepared from the AC with higher micropore content and highly hydrophilic surface. High content of hydrogen bond complex formed between the functional group on hydrophilic surface with H2O, which will slow down the TiO2 precursor-H2O reaction. In such situation, the effect of TiO2 becomes unfavorable as the loading amount of TiO2 is less and the micropore can also be blocked. PMID:25576198

  2. Composite materials: A compilation

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

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

    DOEpatents

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

    2007-07-17

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

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

    DOEpatents

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

    2004-03-23

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

  5. Chemical Compatibility of Polymeric Materials.

    ERIC Educational Resources Information Center

    Solen, Kenneth A.; Kuchar, Marvin C.

    1990-01-01

    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)

  6. Risk assessment for chemical pickling of metals contaminated by radioactive materials.

    PubMed

    Donzella, A; Formisano, P; Giroletti, E; Zenoni, A

    2007-01-01

    In recent years, many cases of contamination of metal scraps by unwanted radioactive materials have occurred. Moreover, international organisations are evaluating the possibility to re-use or to recycle metals coming from nuclear power plants. The metal recycling industry has started to worry about radiation exposure of workers that could be in contact with contaminated metals during each manufacturing phase. Risks are strongly dependent on the radiation source features. The aim of this study is to perform risk assessment for workers involved in chemical pickling of steel coils. Monte Carlo simulations have been performed, using the MCNP package and considering coils contaminated with (60)Co, (137)Cs, (241)Am and (226)Ra. Under the most conservative conditions (coil contaminated with 1.0 kBq g(-1) of (60)Co), the dose assessment results lower than the European dose limit for the population (1 mSv y(-1)), considering a maximum number of 10 contaminated coils handled per year. The only exception concerns the case of (241)Am, for which internal contamination could be non- negligible and should be verified in the specific cases. In every case, radiation exposure risk for people standing at 50 m from the coil is widely <1 mSv y(-1). PMID:16849378

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

    PubMed

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

    2006-01-01

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

  8. Preparation for CeO2/Nanographite Composite Materials and Electrochemical Degradation of Phenol by CeO2/Nanographite Cathodes.

    PubMed

    Yu, Li; Yu, Xiujuan; Sun, Tianyi; Wang, Na

    2015-07-01

    CeO2/nanographite (CeO2/nano-G) composite materials were got by chemical precipitation method with nanographite (nano-G) and cerous nitrate hexahydrate as raw materials. The microstructures of CeO2/nano-G composite materials were characterized by means of SEM, XRD, XPS and Raman. The cathodes were made by nano-G and CeO2/nano-G composite materials, respectively. The electrolysis phenol was conducted by the diaphragm cell prepared cathode and the Ti/RuO2 anode. The results indicated that the Cerium oxide is mainly in nanoscale spherical state, uniformly dispersed in the nanographite sheet surface, and there are two different oxidation states for elemental Ce, namely, Ce(III) and Ce(IV). In the diaphragm electrolysis system with the aeration conditions, the degradation rate of phenol reached 93.9% under 120 min's electrolysis. Ceria in the cathode materials might lead to an increase in the local oxygen concentration, which accelerated the two-electron reduction of O2 to hydrogen peroxide (H2O2). The removal efficiency of phenol by using the CeO2/nano-G composite cathode was better than that of the nano-G cathode. PMID:26373057

  9. Advertising Content in Physical Activity Print Materials.

    ERIC Educational Resources Information Center

    Cardinal, Bradley J.

    2002-01-01

    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

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  11. Chemical composition of Hanford Tank SY-102

    SciTech Connect

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

    1993-12-01

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

  12. Magnetic and electromagnetic properties of composites of iron oxide and Co-B alloy prepared by chemical reduction

    NASA Astrophysics Data System (ADS)

    Li, XueAi; Han, XiJiang; Du, YunChen; Xu, Ping

    2011-01-01

    Magnetic and electromagnetic properties were investigated on the composites of iron oxide and Co-B alloy, which were prepared by a modified chemical reduction method. The composites are characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM). The complex electromagnetic parameters (permittivity ?r= ?r'+j ?r? and permeability ?r= ?r'+j ?r?) of paraffin mixed composite samples (paraffin:composites=1:1 in mass ratio) were measured in the frequency range 2-18 GHz by vector network analyzer. The measured real part ( ?r') and imaginary part ( ?r?) of the relative permittivity show two resonant peaks in the range of 2-18 GHz. The imaginary parts of relative permeability ( ?r?) of all samples exhibited one broad resonant peak over the 2-8 GHz range. The ?r? of samples with higher molar ratio of Co to Fe (C and D) shows negative values within 13-18 GHz, which exhibit resonant and antiresonant permeabilities simultaneously. Calculation results indicated that the reflection loss values of the composites and paraffin wax mixtures are less than -10 dB with frequency width of about 6 GHz at the matching thickness.

  13. Environmental effects of oilfield chemicals on composite

    SciTech Connect

    Sorem, R.M.

    1998-12-31

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

  14. Three-dimensional microstructural design of woven fabric composite material by homogenization method

    SciTech Connect

    Takano, Naoki; Zako, Masaru

    1995-11-01

    The strength of woven fabric composite materials depends on the microstructural geometry. However, the conventional methods for mechanical analysis, which have been widely used so far, are insufficient because they cannot take into account for the three-dimensional microstructure. In this study, three-dimensional homogenization method is shown to be effective for the evaluations of the material constants, microscopic stresses and the strength. It has been found that the transverse stresses in the direction of lamination play an important role for the fracture of both fiber bundle and resin. Also, the effect of the mismatched lay-up on the strength has been investigated. It has well been predicted that the mismatched lay-up causes the reduction of the strength and the difference of crack initiation in the resin. These simulations give a new concept of the microstructural design of the composite materials.

  15. Silicon carbon nitride films as new materials obtained by plasma chemical vapor deposition from novel precursor

    NASA Astrophysics Data System (ADS)

    Smirnova, Tamara P.; Shmakov, Aleksander N.; Badalian, Aram M.; Kaichev, Vasiliy V.; Bukhtiyarov, Valery I.; Rachlin, Vladimer I.; Fomina, Anna N.

    2001-07-01

    Silicon carbonitride films were synthesized by RP CVD process using the novel single-source precursor that is derivative of 1,1-dimethylhydrazine, (CH3)2HSiNHN(CH3)2. The films were characterized by X- ray photoelectron (XPS), infrared (FTIR) and ultraviolet (UV) spectroscopy. The microstructure of the films was examined by scanning electron microscopy (SEM) and diffraction of synchrotron radiation (DSR) methods. XPS and FT-IR spectroscopy studies showed that the Si-C and Si-N are the main bonds in the deposited films. Concerning the C-N bonds, the results are less obvious: they are either negligible or not present at all. The films were found to be predominately amorphous with a number of crystallites within the unstructured matrix. The crystals appearance, their dimensions and crystal form did not depend on substrate temperature. We hypothesized that crystallization could happen in the gas phase during deposition or nanocrystals were formed by the strain induced after a certain thickness of the amorphous film. The crystals were assigned to the structure closed to (alpha) -Si3N4 phase. According to FTIR and XPS data it is clear that the chemical bonding and the atomic local order in the amorphous matrix are much more complicated than those of Si3N4-SiC mixtures. We concluded that tetrahedral configurations of silicon carbide and silicon nitride units with mixed C/N environment are hypothetically formed. The films are highly resistant to thermal degradation. It was also demonstrated that this new material has a band gap that was variable from 2.0 eV to 4.7 eV.

  16. Dual bioactivities of essential oil extracted from the leaves of Artemisia argyi as an antimelanogenic versus antioxidant agent and chemical composition analysis by GC/MS.

    PubMed

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

    2012-01-01

    The study was aimed at investigating the antimelanogenic and antioxidant properties of essential oil when extracted from the leaves of Artemisia argyi, then analyzing the chemical composition of the essential oil. The inhibitory effect of the essential oil on melanogenesis was evaluated by a mushroom tyrosinase activity assay and B16F10 melanoma cell model. The antioxidant capacity of the essential oil was assayed by spectrophotometric analysis, and the volatile chemical composition of the essential oil was analyzed with gas chromatography-mass spectrometry (GC/MS). The results revealed that the essential oil significantly inhibits mushroom tyrosinase activity (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

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

    PubMed Central

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

    2012-01-01

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

  18. Correlation of rocket propulsion fuel properties with chemical composition using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry followed by partial least squares regression analysis

    SciTech Connect

    Kehimkar, Benjamin; Hoggard, Jamin C.; Marney, Luke C.; Billingsley, Matthew; Fraga, Carlos G.; Bruno, Thomas J.; Synovec, Robert E.

    2014-01-31

    There is an increased need to more fully assess and control the composition of kerosene based rocket propulsion fuels, namely RP-1 and RP-2. In particular, it is crucial to be able to make better quantitative connections between the following three attributes: (a) fuel performance, (b) fuel properties (flash point, density, kinematic viscosity, net heat of combustion, hydrogen content, etc) and (c) the chemical composition of a given fuel (i.e., specific chemical compounds and compound classes present as a result of feedstock blending and processing). Indeed, recent efforts in predicting fuel performance through modeling put greater emphasis on detailed and accurate fuel properties and fuel compositional information. In this regard, advanced distillation curve (ADC) metrology provides improved data relative to classical boiling point and volatility curve techniques. Using ADC metrology, data obtained from RP-1 and RP-2 fuels provides compositional variation information that is directly relevant to predictive modeling of fuel performance. Often, in such studies, one-dimensional gas chromatography (GC) combined with mass spectrometry (MS) is typically employed to provide chemical composition information. Building on approaches using GC-MS, but to glean substantially more chemical composition information from these complex fuels, we have recently studied the use of comprehensive two dimensional gas chromatography combined with time-of-flight mass spectrometry (GC × GC - TOFMS) to provide chemical composition data that is significantly richer than that provided by GC-MS methods. In this report, by applying multivariate data analysis techniques, referred to as chemometrics, we are able to readily model (correlate) the chemical compositional information from RP-1 and RP-2 fuels provided using GC × GC - TOFMS, to the fuel property information such as that provided by the ADC method and other specification properties. We anticipate that this new chemical analysis strategy will have broad implications for the development of high fidelity composition-property models, leading to an optimized approach to fuel formulation and specification for advanced engine cycles.

  19. Enhanced toughness and stable crack propagation in a novel tungsten fibre-reinforced tungsten composite produced by chemical vapour infiltration

    NASA Astrophysics Data System (ADS)

    Riesch, J.; Höschen, T.; Linsmeier, Ch; Wurster, S.; You, J.-H.

    2014-04-01

    Tungsten is a promising candidate for the plasma-facing components of a future fusion reactor, but its use is strongly restricted by its inherent brittleness. An innovative concept to overcome this problem is tungsten fibre-reinforced tungsten composite. In this paper we present the first mechanical test of such a composite material using a sample containing multiple fibres. The in situ fracture experiment was performed in a scanning electron microscope for close observation of the propagating crack. Stable crack propagation accompanied with rising load bearing capacity is observed. The fracture toughness is estimated using the test results and the surface observation.

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

    PubMed

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

    2008-12-15

    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

  1. Binary stars: Mass transfer and chemical composition

    NASA Technical Reports Server (NTRS)

    Lambert, D. L.

    1982-01-01

    It is noted that mass exchange (and mass loss) within a binary system should produce observable changes in the surface chemical composition of both the mass losing and mass gaining stars as a stellar interior exposed to nucleosyntheses is uncovered. Three topics relating mass exchange and/or mass loss to nucleosynthesis are sketched: the chemical composition of Algol systems; the accretion disk of a cataclysmic variable fed by mass from a dwarf secondary star; and the hypothesis that classical Ba II giants result from mass transfer from a more evolved companion now present as a white dwarf.

  2. The devolatilization of stellar material that produces rocky planets is more accurately described by non-equilibrium partial sublimation rather than equilibrium partial condensation: implications for water content

    NASA Astrophysics Data System (ADS)

    Lineweaver, Charles H.

    2015-08-01

    Elemental "50% condensation temperatures" have been used for decades in planetary science to represent the relative volatility of elements. These temperatures are based on taking a hot gas of solar composition and cooling it, with all elements and compounds in chemical equilibrium with each other. Although condensation temperatures are useful as a first approximation, they do not reflect the dominant physical mechanisms responsible for the devolatilization that leads to the formation of rocky planets. Stars begin to form with protoplanetary accretion disks in the densest and coldest (~ 5-30 K) cores of molecular clouds. As the star and midplane of the accretion disk heat up, the cold condensed and clumped material begins to sublimate and fractionate. Because of the clumping and the heating of previously cold material, the devolatilization that leads to rocky planet formation is produced by non-equilibrium partial sublimation, not equilibrium partial condensation. The difference between the temperatures when an element is 50% ("partially") sublimated from a non-equilibrium clump, and 50% condensed at equilibrium is particularly large for the dominant elements carbon and oxygen. Using the elementatl abundance differences between the Sun and the Earth and plotting them as a function of how refractory or volatile an element is, we make new higher estimates of the temperatures that should be used for carbon and oxygen to parametrize the devolatilization of stellar material in protoplanetary disks to produce rocky planets. These modifications have important implications for the C/O ratio that controls redox state and the main chemical composition of a planet, and the amount of H2O on a planet.

  3. Composite structural materials. [aircraft structures

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

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

  4. An Overview of Recent Development in Composite Catalysts from Porous Materials for Various Reactions and Processes

    PubMed Central

    Xie, Zaiku; Liu, Zhicheng; Wang, Yangdong; Yang, Qihua; Xu, Longya; Ding, Weiping

    2010-01-01

    Catalysts are important to the chemical industry and environmental remediation due to their effective conversion of one chemical into another. Among them, composite catalysts have attracted continuous attention during the past decades. Nowadays, composite catalysts are being used more and more to meet the practical catalytic performance requirements in the chemical industry of high activity, high selectivity and good stability. In this paper, we reviewed our recent work on development of composite catalysts, mainly focusing on the composite catalysts obtained from porous materials such as zeolites, mesoporous materials, carbon nanotubes (CNT), etc. Six types of porous composite catalysts are discussed, including amorphous oxide modified zeolite composite catalysts, zeolite composites prepared by co-crystallization or overgrowth, hierarchical porous catalysts, host-guest porous composites, inorganic and organic mesoporous composite catalysts, and polymer/CNT composite catalysts. PMID:20559508

  5. Chemical composition of volatile oils from the pericarps of Indian sandalwood (Santalum album) by different extraction methods.

    PubMed

    Zhang, Xin Hua; da Silva, Jaime A Teixeira; Jia, Yong Xia; Zhao, Jie Tang; Ma, Guo Hua

    2012-01-01

    The chemical composition of volatile compounds from pericarp oils of Indian sandalwood, Santalum album L., isolated by hydrodistillation and solvent extraction, were analyzed by GC and GC-MS. The pericarps yielded 2.6 and 5.0% volatile oil by hydrodistillation and n-hexane extraction, and they were colorless and yellow in color, respectively. A total of 66 volatile components were detected. The most prominent compounds were palmitic and oleic acids, representing about 40-70% of the total oil. Many fragrant constituents and biologically active components, such as alpha- and beta-santalol, cedrol, esters, aldehydes, phytosterols, and squalene were present in the pericarp oils. This is the first report of the volatile composition of the pericarps of any Santalum species. PMID:22428257

  6. Health, safety and environmental requirements for composite materials

    NASA Technical Reports Server (NTRS)

    Hazer, Kathleen A.

    1994-01-01

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

  7. Improved Silica Aerogel Composite Materials

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

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

    PubMed

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

    2013-12-15

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

  9. Cell wall fermentation kinetics impacted more by lignin content and cross-linking than by diverse shifts in lignin composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We used a biomimetic model system to ascertain how lignification and diverse shifts in lignin cross-linking and composition influence cell wall fermentation. Primary cell walls from nonlignified maize cell suspensions were artificially lignified with varying ratios of normal monolignols (coniferyl a...

  10. 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...

  11. Cell attachment to hydrogel-electrospun fiber mat composite materials.

    PubMed

    Han, Ning; Johnson, Jed K; Bradley, Patrick A; Parikh, Kunal S; Lannutti, John J; Winter, Jessica O

    2012-01-01

    Hydrogels, electrospun fiber mats (EFMs), and their composites have been extensively studied for tissue engineering because of their physical and chemical similarity to native biological systems. However, while chemically similar, hydrogels and electrospun fiber mats display very different topographical features. Here, we examine the influence of surface topography and composition of hydrogels, EFMs, and hydrogel-EFM composites on cell behavior. Materials studied were composed of synthetic poly(ethylene glycol) (PEG) and poly(ethylene glycol)-poly(?-caprolactone) (PEGPCL) hydrogels and electrospun poly(caprolactone) (PCL) and core/shell PCL/PEGPCL constituent materials. The number of adherent cells and cell circularity were most strongly influenced by the fibrous nature of materials (e.g., topography), whereas cell spreading was more strongly influenced by material composition (e.g., chemistry). These results suggest that cell attachment and proliferation to hydrogel-EFM composites can be tuned by varying these properties to provide important insights for the future design of such composite materials. PMID:24955629

  12. Piezoelectric composite materials

    NASA Technical Reports Server (NTRS)

    Kiraly, L. J. (inventor)

    1983-01-01

    A laminated structural devices has the ability to change shape, position and resonant frequency without using discrete motive components. The laminate may be a combination of layers of a piezoelectrically active, nonconductive matrix material. A power source selectively places various levels of charge in electrically conductive filaments imbedded in the respective layers to produce various configurations in a predetermined manner. The layers may be electrically conductive having imbedded piezoelectrically active filaments. A combination of layers of electrically conductive material may be laminated to layers of piezoelectrically active material.

  13. Effects of ionizing radiation on the chemical structure, crystalline content and molecular weight distribution of various teflon resins

    SciTech Connect

    Fisher, W.K.

    1981-01-01

    The radiation used in this work was 0.8 MeV electrons. The effects of post-irradiation annealing on the chemical composition and crystalline content are also analyzed. Radiation-induced changes in the chemical composition and the role of oxygen and water vapor in these changes was determined by infrared spectroscopy of PTFE (polytetrafluoroethylene) irradiated in ambient air, wet and dry oxygen atmosphere and under vacuum.

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

    SciTech Connect

    Ramm, D.A.J.; Clyne, T.W.; Sturgeon, A.J.; Dunkerton, S.

    1994-12-31

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

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

    PubMed

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

    2013-08-28

    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

  16. Composite materials and method of making

    DOEpatents

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

    2011-05-17

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

  17. Ultrasonic Inspection Of Composite-Material Paraboloid

    NASA Technical Reports Server (NTRS)

    Chern, E. James

    1994-01-01

    Ultrasonic imaging system scanning three-dimensional curved surfaces developed. In original application, system used to determine integrity of composite-material paraboloidal reflector and its supporting structure. System also used to inspect composite-material structures with curved surfaces other than paraboloids, provided surfaces describable by mathematical functions. Position and orientation of transducer adjusted continuously to maintain normal incidence.

  18. Carbon Materials for Chemical Capacitive Energy Storage

    SciTech Connect

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

    2011-09-26

    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.

  19. Carbon materials for chemical capacitive energy storage.

    PubMed

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

    2011-11-01

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

  20. Composite structural materials. [aircraft applications

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  1. Nondestructive Characterization of Composite Materials

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Y.

    1993-01-01

    Increasingly, composite materials are applied to fracture-critical structures of aircraft and spacecraft...Ultrasonics offer the most capable inspection technology and recently developed techniques appear to improve this technology significantly... Recent progress in ultrasonic NDE of composites will be reviewed.

  2. The Catalytic Behaviour of NanoAg@montmorillonite Composite Materials

    NASA Astrophysics Data System (ADS)

    Karlíková, Martina; Kvítek, Libor; Prucek, Robert; Panáček, Aleš; Filip, Jan; Pechoušek, Jiří; Adegboyega, Nathaniel F.

    The preparation of nanoAg@montmorillonite composite materials and their catalytic activity is reported in this article. The nanoAg@montmorillonite composite materials were prepared by the adsorption of silver NPs, with an average size about 30 nm, from their aqueous dispersion onto two types of montmorillonite with different chemical composition. Silver NPs were prepared via modified Tollens process, which involves the reduction of [Ag(NH3)2]+ complex cation by maltose. The amount of silver NPs anchored onto the MMT surfaces was determined by UV-VIS spectroscopy; the decrease in absorbance of the dispersion after the adsorption was monitored. Prepared nanocomposite materials were subsequently characterized by means of transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). The reduction of 4-nitrophenol by sodium borohydride was chosen to examine the catalytic properties of the synthesized silver nanocomposite materials.

  3. Clues for biomimetics from natural composite materials

    PubMed Central

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

    2013-01-01

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

  4. Clues for biomimetics from natural composite materials.

    PubMed

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

    2012-09-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  6. Chemical compositions of primitive solar system particles

    NASA Technical Reports Server (NTRS)

    Sutton, Steve R.; Bajt, S.

    1994-01-01

    Chemical studies of micrometeorites are of fundamental importance primarily because atmospheric entry selection effects (such as destruction of friable objects) are less significant than those for conventional meteorites. As a result, particles that have experienced very little postaccretional processing have a significant chance of surviving the Earth encounter and subsequent collection. Thus, chemical analyses of these relatively unaltered micrometeorites may lead to a better understanding of the compositions of the most primitive materials in the solar system and thereby constrain the conditions (physical and chemical) that existed in the early solar nebula. Micrometeorites have been collected from the stratosphere, polar ices, and ocean sediments, but the stratospheric collection is the best source for the most unaltered material because they are small and are not heated to their melting points. Despite the fact that the stratospheric micrometeorites have masses in the nanogram range, a variety of microanalytical techniques have been applied to bulk chemical analyses with part-per-million sensitivity. In some cases, multi-disciplinary studies (e.g., chemistry and mineralogy) have been performed on individual particles. The first-order conclusion is that the chondrite-like particles are chemically similar to carbonaceous chondrites but in detail are distinct from members of the conventional meteorite collection. The purpose of this paper is to provide an overview of the results to date and identify important areas for further study.

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

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  8. Carbon nanotube composite materials

    DOEpatents

    O'Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  9. Combined studies of chemical composition of urine sediments and kidney stones by means of infrared microspectroscopy.

    PubMed

    Tamoaityt?, Sandra; Hendrixson, Vaiva; elvys, Ar?nas; Tyla, Ram?nas; Ku?inskien?, Zita A; Jankevi?ius, Feliksas; Pu?etait?, Milda; Jablonskien?, Valerija; ablinskas, Valdas

    2013-02-01

    Results of the structural analysis of urinary sediments by means of infrared spectral microscopy are presented. The results are in good agreement with the results of standard optical microscopy in the case of single-component and crystalline urinary sediments. It is found that for noncrystalline or multicomponent sediments, the suggested spectroscopic method is superior to optical microscopy. The chemical structure of sediments of any molecular origin can be elucidated by this spectroscopic method. The method is sensitive enough to identify solid particles of drugs present in urine. Sulfamethoxazole and traces of other medicines are revealed in this study among the other sediments. We also show that a rather good correlation exists between the type of urinary sediments and the renal stones removed from the same patient. Spectroscopic studies of urinary stones and corresponding sediments from 76 patients suffering from renal stone disease reveal that in 73% of cases such correlation exists. This finding is a strong argument for the use of infrared spectral microscopy to prevent kidney stone disease because stones can be found in an early stage of formation by using the nonintrusive spectroscopic investigation of urinary sediments. Some medical recommendations concerning the overdosing of certain pharmaceuticals can also be derived from the spectroscopic studies of urinary sediments. PMID:23429795

  10. Assessment of The Compatibility of Composite Materials With High-Test Hydrogen Peroxide

    NASA Technical Reports Server (NTRS)

    Gostowski, Rudy; Griffin, Dennis E. (Technical Monitor)

    2000-01-01

    The compatibility of composite materials with high-test hydrogen peroxide (HTP) was assessed using various chemical and mechanical techniques. Methods included classical schemes combining concentration assay with accelerated aging by means of a heated water bath. Exothermic reactivity was observed using Isothermal Microcalorimetry. Mechanical Properties testing determined degradation of the composite material. Photoacoustic Infrared Spectroscopy was used to monitor chemical alteration of the resin matrix. Other materials were examined including some polymers and metals.

  11. Chemical modification of lignocellulosic materials by irradiation with Nd-YAG pulsed laser

    NASA Astrophysics Data System (ADS)

    Botaro, V. R.; dos Santos, C. G.; Arantes Jnior, G.; da Costa, A. R.

    2001-11-01

    Most reports about modification of lignocellulosics are mainly based on chemical modifications such as specific reactions on hydroxyl groups of cellulose. In this work, we describe the irradiation of Whatman 5 filter paper, microcrystalline cellulose and organosolv lignin with Nd-YAG laser pulses at 1064 nm. The chemical and structural properties of the degraded products were investigated by using FTIR and UV spectroscopies, conductimetrical and SEC analyses. While irradiation affects molar mass and polydispersity of lignin, no detrimental effects caused by Nd-YAG laser treatments were observed for cellulose samples. These results demonstrate that Nd-YAG laser can be used as a practical and selective degradation tool, opening a new field for obtaining surface modified natural fibers.

  12. Chemical Composition of Aerosol Particles Emitted by a Passenger Car Engine Fueled by Ethanol/Gasoline Mixtures

    NASA Astrophysics Data System (ADS)

    Medrano, J. M.; Gross, D. S.; Dutcher, D. D.; Drayton, M.; Kittelson, D.; McMurry, P.

    2007-12-01

    With concerns of national security, climate change, and human health, many people have called for oil independence for the United States and for the creation of alternative fuels. Ethanol has been widely praised as a viable alternative to petroleum-based fuels, due to the fact that it can be produced locally. A great deal of work has been done to characterize the energy balance of ethanol production versus consumption, but there have been fewer studies of the environmental and health impacts of emissions from combustion of ethanol/gasoline mixtures such as those burned in the modern vehicle fleet. To study the particulate emissions from such fuels, different ethanol/gasoline fuel mixtures with 0, 20, 40, and 85% ethanol were burned in a dynamometer-mounted automobile engine. The engine exhaust was diluted and sampled with two aerosol Time-of-Flight Mass Spectrometers (TSI 3800 ATOFMS), sampling different particle size ranges (50-500 nm and 150-3000 nm, respectively), to measure size and composition of the emitted aerosol particles. A variety of other aerosol characterization techniques were also employed to determine the size distribution of the aerosol particles, the mass emission rate from the engine, and the concentration of polycyclic aromatic hydrocarbons (PAHs) and elemental carbon (EC) in the particle emissions. Here we will focus on results from the ATOFMS, which provides us with a particle size and mass spectra - for both negative and positive ions - for each particle that is sampled. Particles being emitted were found to contain primarily PAHs, elemental carbon (EC), nitrates, and sulfates. Particles were analyzed to investigate trends in particle composition as a function of fuel ethanol content, particle size, and for the types of particles emitted. A trend in particle type as a function of fuel ethanol content was evident in smaller particles, and trends in composition as a function of particle size were visible across the entire size range sampled.

  13. Chemical Composition and Biological Activity of Extracts Obtained by Supercritical Extraction and Ethanolic Extraction of Brown, Green and Red Propolis Derived from Different Geographic Regions in Brazil

    PubMed Central

    Machado, Bruna Aparecida Souza; Silva, Rejane Pina Dantas; Barreto, Gabriele de Abreu; Costa, Samantha Serra; da Silva, Danielle Figuerêdo; Brandão, Hugo Neves; da Rocha, José Luiz Carneiro; Dellagostin, Odir Antônio; Henriques, João Antônio Pegas; Umsza-Guez, Marcelo Andres; Padilha, Francine Ferreira

    2016-01-01

    The variations in the chemical composition, and consequently, on the biological activity of the propolis, are associated with its type and geographic origin. Considering this fact, this study evaluated propolis extracts obtained by supercritical extraction (SCO2) and ethanolic extraction (EtOH), in eight samples of different types of propolis (red, green and brown), collected from different regions in Brazil. The content of phenolic compounds, flavonoids, in vitro antioxidant activity (DPPH and ABTS), Artepillin C, p-coumaric acid and antimicrobial activity against two bacteria were determined for all extracts. For the EtOH extracts, the anti-proliferative activity regarding the cell lines of B16F10, were also evaluated. Amongst the samples evaluated, the red propolis from the Brazilian Northeast (states of Sergipe and Alagoas) showed the higher biological potential, as well as the larger content of antioxidant compounds. The best results were shown for the extracts obtained through the conventional extraction method (EtOH). However, the highest concentrations of Artepillin C and p-coumaric acid were identified in the extracts from SCO2, indicating a higher selectivity for the extraction of these compounds. It was verified that the composition and biological activity of the Brazilian propolis vary significantly, depending on the type of sample and geographical area of collection. PMID:26745799

  14. Chemical Composition and Biological Activity of Extracts Obtained by Supercritical Extraction and Ethanolic Extraction of Brown, Green and Red Propolis Derived from Different Geographic Regions in Brazil.

    PubMed

    Machado, Bruna Aparecida Souza; Silva, Rejane Pina Dantas; Barreto, Gabriele de Abreu; Costa, Samantha Serra; Silva, Danielle Figuerdo da; Brando, Hugo Neves; Rocha, Jos Luiz Carneiro da; Dellagostin, Odir Antnio; Henriques, Joo Antnio Pegas; Umsza-Guez, Marcelo Andres; Padilha, Francine Ferreira

    2016-01-01

    The variations in the chemical composition, and consequently, on the biological activity of the propolis, are associated with its type and geographic origin. Considering this fact, this study evaluated propolis extracts obtained by supercritical extraction (SCO2) and ethanolic extraction (EtOH), in eight samples of different types of propolis (red, green and brown), collected from different regions in Brazil. The content of phenolic compounds, flavonoids, in vitro antioxidant activity (DPPH and ABTS), Artepillin C, p-coumaric acid and antimicrobial activity against two bacteria were determined for all extracts. For the EtOH extracts, the anti-proliferative activity regarding the cell lines of B16F10, were also evaluated. Amongst the samples evaluated, the red propolis from the Brazilian Northeast (states of Sergipe and Alagoas) showed the higher biological potential, as well as the larger content of antioxidant compounds. The best results were shown for the extracts obtained through the conventional extraction method (EtOH). However, the highest concentrations of Artepillin C and p-coumaric acid were identified in the extracts from SCO2, indicating a higher selectivity for the extraction of these compounds. It was verified that the composition and biological activity of the Brazilian propolis vary significantly, depending on the type of sample and geographical area of collection. PMID:26745799

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

    PubMed

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

    2012-07-01

    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

  16. Chemical compatibility of cartridge materials

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  17. Determination of the composition of the organic matter chemically stabilized by agricultural soil clay minerals: Spectroscopy and Density Fractionation

    NASA Astrophysics Data System (ADS)

    Oufqir, Sofia; Bloom, Paul; Toner, Brandy; Hatcher, Patrick

    2014-05-01

    The interactions between soil organic matter and clay minerals are considered important processes because of their ability to sequester C in soil for long periods of time, and hence control C in the global C cycle when present. However, differing results have been reported regarding the composition of the soil organic matter - aromatic fractions versus aliphatic fractions - associated with clay minerals. To clarify this critical issue and better understand the C sequestration process in soils, we aimed to determine the nature of the chemically bound natural organic matter on clay surfaces, and to probe the speciation and spatial distribution of C in the soil clay nanoparticles using direct spectroscopic measurements namely solid-state CP-MAS and DP-MAS 13C NMR spectroscopy, x-ray diffraction spectroscopy (XRD), and scanning transmission x-ray microscopy (STXM). We tested the hypotheses that peptides and polysaccharides are stabilized by the smectite-illite clay while the lipids and black carbon are a separate phase; and that they are evenly distributed on clay surfaces. A soil clay fraction (5.5% organic C) was isolated from the surface of a prairie soil (Mollisol) in southwestern Minnesota, characterized by a pH 6.0, 32.5% clay content, and 3.7% organic carbon, using a sonication-sedimentation-siphoning process in distilled water. Then was subjected to density separation combined with low energy ultrasonic dispersion to separate the free organic and black C (light fraction) from the chemically bound C (heavy fraction). The XRD results indicated a dominance of interstratified smectite-illite clays in soil. The 13C-NMR spectra of the soil clay fraction suggested that polysaccharides and polypeptides are the prevailing components of the organic matter associated with the mineral clay, with only a minor component of aromatic C. The light fraction has strong alkyl C-H bands characteristic of fatty acids plus strong C-O bands characteristic of polysaccharides, including the anomeric C band centered at 105 ppm. The aromatic band at 130 ppm and the phenolic C-O band at 150 pm are strong as well indicating the presence of black carbon and lignin-derived components, contrary to the heavy fraction where they are almost absent. STXM results indicated that the proteins are abundant in the soil clay fraction, separate from lipids, and partially associated with saccharides. The black carbon constitutes a separate phase, but is amply present with lipids and lignin-derived compounds in the light fraction. We conclude that (1) the smectite-illite sheets in our soils preferentially retain peptides, and polysaccharides favoring the protection of these normally readily biodegradable fractions relative to the lignin-derived phenolic components; (2) the black carbon constitutes a major component of the light fraction, and is partially attached to the organic matter bonded with the smectitic clays; and (3) the lipids are associated with soil clay fraction as a separate phase, but are not bound to clay minerals.

  18. Piezoelectric Nanoparticle-Polymer Composite Materials

    NASA Astrophysics Data System (ADS)

    McCall, William Ray

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

  19. Chemical Composition and Heterogeneity of Wild 2 Cometary Particles Determined by Synchrotron X-ray Fluorescence

    SciTech Connect

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

    2008-01-01

    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 fragments in each track and scaling by the ratio of total Fe in the map and total Fe in the fragments. In general, whole-track and terminal-particle abundances are dissimilar. The total Fe masses ranged from 4 to 2200 pg, corresponding to impactors in the size range of 2.7 to 22 {mu}m if Fe abundances are equal to the chondritic value. Systematic variations in element abundance with fragment distance from the aerogel entry point were generally subtle but were pronounced in one track (C2115,19). In this track, Zn/Fe was about three orders of magnitude higher at the top, Cr/Fe was two orders of magnitude higher at the bottom, and S was relatively uniform. Compositional convergence data showed that typically analysis of {approx}10 fragments was needed to reach convergent whole-track abundance. Zinc was an exception, showing nonconvergent profiles and steps due to the presence of rare, high-Zn fragments. The resulting wholetrack elemental abundances show diverse patterns that are generally chondritic (i.e., within a factor of three of CI abundances) with some exceptions, notably depletions in S and enrichments in the moderately volatile elements Cu, Zn, and Ga. Enrichments in large ion lithophile elements relative to Fe were observed in one track. Correlation matrices showed several strong elemental correlations, notably selenium associated with sulfur (sulfides), a ubiquitous correlation of the first-row transition metals Cr, Mn, and Fe attributed to the presence of pyroxene, and enrichments of gallium associated with calcium, likely affiliated with Mg-Al glass.

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

    SciTech Connect

    Shyu, S.S.; Wu, S.R.; Sheu, G.S.

    1996-12-31

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

  1. Changes in the chemical composition of basil caused by different drying procedures.

    PubMed

    Di Cesare, Luigi Francesco; Forni, Elisabetta; Viscardi, Daniela; Nani, Renato Carlo

    2003-06-01

    Basil (Ocimum basilicum L.) leaves were dried using a microwave oven at atmospheric pressure or two traditional methods: air-drying at 50 degrees C and freeze-drying. The microwave-drying was carried out at different powers and times on raw basil leaves, while for air and freeze-drying techniques, both raw and blanched leaves were used. The raw and dried basil was analyzed for selected aroma compounds by gas chromatography/mass spectrometry-selected-ion-monitoring, the chlorophyll a and b by HPLC and the color by a reflected-light colorimeter. For dried samples microwaved for 1 min at 270, 2 min at 440, 1 min at 650, and 1 min at 1100 W, the percentage retentions of the characteristic volatile compounds (eucalyptol, linalool, eugenol, and methyl eugenol) were higher than in the samples dried by traditional methods, with the exception of freeze-dried unblenched basil. Microwave drying allowed a larger retention of chlorophyll pigments than air-drying and freeze-drying (with or without blanching) and preserved the color of the raw basil. Microwave drying requires a much shorter treatment and implied the simultaneous blanching of the material. PMID:12769527

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

    NASA Astrophysics Data System (ADS)

    Lemoine, Fabrice; Castanet, Guillaume

    2013-07-01

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

  3. Lunar Skylights and Their Chemical Compositions

    NASA Astrophysics Data System (ADS)

    Wong, J.; Torres, J.; FitzHoward, S.; Luu, E.; Hua, J.; Irby, R.

    2013-12-01

    In 2009, the Japanese orbiter, SELenological and Engineering Explorer (SELENE) discovered a skylight on the near side of the moon. Skylights are collapsed ceilings of rilles, thought to be caused by moonquakes, meteoroids, or incomplete formation of these lava tube ceilings. Since then, NASA's Lunar Reconnaissance Orbiter has discovered two more skylights, also located on the near side of the moon. Previous research has shown that the physical characteristics of known rilles, can be used as indicators of the presence of yet undiscovered rille and lava dome locations across the lunar surface. We hypothesize that skylights have a signature chemical composition that is unique, and can be used to predict the location of additional skylights on the surface of the moon. For this study, we compared chemical composition data of the three mare sites containing skylights with the 21 mare sites without skylights. Using the software JMARS for the Moon, we compiled multiple datasets to measure the concentrations of 13 different chemical compounds including calcium, iron oxide, titanium dioxide, and thorium. We then conducted a two-tailed T-test of the data, which generated probability values for the mean differences across all 13 chemical compounds of the maria sites with skylights and the maria sites without skylights. Our results show that there is no statistical difference in chemical composition across all of the maria sites examined. Therefore, we conclude that chemical composition does not predict or indicate potential skylight locations on the moon. Further research on other skylight characteristics, for example depth and surrounding underground lava channels, may shed light on the relationships between mare and skylights locations. Three Skylight Locations Found on Lunar Surface 100m View of Mare Tranquilitatis Skylight

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

    NASA Astrophysics Data System (ADS)

    Douglas, Amber M.

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

  5. Nanophase and Composite Optical Materials

    NASA Technical Reports Server (NTRS)

    2003-01-01

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

  6. Composite material impregnation unit

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  7. Compositional and functional dynamics of dried papaya as affected by storage time and packaging material.

    PubMed

    Udomkun, Patchimaporn; Nagle, Marcus; Argyropoulos, Dimitrios; Mahayothee, Busarakorn; Latif, Sajid; Müller, Joachim

    2016-04-01

    Papaya has been identified as a valuable source of nutrients and antioxidants, which are beneficial for human health. To preserve the nutritional properties after drying, appropriate storage specifications should be considered. This study aimed to investigate the quality and stability of air-dried papaya in terms of quality dynamics and behavior of bio-active compounds during storage for up to 9 months in two packaging materials: aluminum laminated polyethylene and polyamide/polyethylene. Samples with moisture content (MC) of 0.1328 g g(-1) and water activity (aw) of 0.5 were stored at 30 °C and relative humidity (RH) of 40-50%. The MC, aw, degree of browning (DB) and 5-hydroxymethylfurfural (HMF) content were found to notably increase as storage progressed. On the contrary, there was a significant decrease in antioxidant capacity (DPPH, FRAP and ABTS), total phenolic (TP) and ascorbic acid (AA) contents. Packaging in aluminum laminated polyethylene under ambient conditions was found to better preserve bio-active compounds and retard increases in MC, aw and DB, when compared to polyamide/polyethylene. PMID:26593545

  8. Changes in chemical composition in male turkeys during growth.

    PubMed

    Rivera-Torres, V; Noblet, J; van Milgen, J

    2011-01-01

    In growing animals, requirements for many nutrients (and energy) are determined by the retention of these nutrients. During growth, this retention changes in an absolute way and also between nutrients and energy, resulting in changing nutrient requirements. The objective of this study was to describe the changes in chemical composition in male growing turkeys. The serial slaughter technique was used to determine the composition of amino acids, lipid, ash, and water in feather-free body (FFB) and feathers in male turkeys offered feed ad libitum from 1 to 15 wk of age. Allometric relations were used to describe changes in body composition. The feather content in the body decreased from 6% at 1 wk of age to less than 3% at 15 wk of age. The water and protein content in FFB decreased with increasing FFB mass, with allometric scalars (b) of, respectively, 0.967 and 0.970, whereas the lipid content increased with increasing FFB mass (b = 1.388). The water, protein, and ash content in fat-free FFB was constant and represented, respectively, 71.6, 24.2, and 4.2% of the fat-free FFB mass. The amino acid content of FFB protein was relatively constant and only the Cys content decreased between 1 and 15 wk of age, whereas the Ile content increased. Feathers were mostly composed of protein, and the protein content did not change during growth. During growth, the Lys, Met, Trp, His, Tyr, Asp, and Glu contents in feather protein decreased, whereas the Cys, Val, and Ser contents increased. The contribution of feathers to whole-body amino acid retention ranged from 5% for His to 33% for Cys. On average, the weight gain of FFB contained 21.3% protein and 12.7% lipid, corresponding to an energy content of 10.1 kJ/g. The weight gain of feathers contained 87.4% protein, corresponding to an energy content of 20.4 kJ/g. The results of the present study can be used in a factorial approach to determine nutrient requirements in growing turkeys. PMID:21177445

  9. Chemical composition of Martian fines

    NASA Astrophysics Data System (ADS)

    Clark, B. C.; Baird, A. K.; Weldon, R. J.; Tsusaki, D. M.; Schnabel, L.; Candelaria, M. P.

    1982-11-01

    Of the 21 samples acquired for the Viking X-ray fluorescence spectrometer, 17 were analyzed to high precision. Compared to typical terrestrial continental soils and lunar mare fines, the Martian fines are lower in Al, higher in Fe, and much higher in S and Cl concentrations. Protected fines at the two lander sites are almost indistinguishable, but concentration of the element S is somewhat higher at Utopia. Duricrust fragments, successfully acquired only at the Chryse site, invariably contained about 50% higher S than fines. No elements correlate positively with S, except Cl and possibly Mg. A sympathetic variation is found among the triad Si, Al, Ca; positive correlation occurs between Ti and Fe. Sample variabilities are as great within a few meters as between lander locations (4500 km apart), implying the existence of a universal Martian regolith component of constant average composition. The nature of the source materials for the regolith fines must be mafic to ultramafic.

  10. Risks and reliability of manufacturing processes as related to composite materials for spacecraft structures

    NASA Technical Reports Server (NTRS)

    Bao, Han P.

    1995-01-01

    Fabricating primary aircraft and spacecraft structures using advanced composite materials entail both benefits and risks. The benefits come from much improved strength-to-weight ratios and stiffness-to-weight ratios, potential for less part count, ability to tailor properties, chemical and solvent resistance, and superior thermal properties. On the other hand, the risks involved include high material costs, lack of processing experience, expensive labor, poor reproducibility, high toxicity for some composites, and a variety of space induced risks. The purpose of this project is to generate a manufacturing database for a selected number of materials with potential for space applications, and to rely on this database to develop quantitative approaches to screen candidate materials and processes for space applications on the basis of their manufacturing risks including costs. So far, the following materials have been included in the database: epoxies, polycyanates, bismalemides, PMR-15, polyphenylene sulfides, polyetherimides, polyetheretherketone, and aluminum lithium. The first four materials are thermoset composites; the next three are thermoplastic composites, and the last one is is a metal. The emphasis of this database is on factors affecting manufacturing such as cost of raw material, handling aspects which include working life and shelf life of resins, process temperature, chemical/solvent resistance, moisture resistance, damage tolerance, toxicity, outgassing, thermal cycling, and void content, nature or type of process, associate tooling, and in-process quality assurance. Based on industry experience and published literature, a relative ranking was established for each of the factors affecting manufacturing as listed above. Potential applications of this database include the determination of a delta cost factor for specific structures with a given process plan and a general methodology to screen materials and processes for incorporation into the current conceptual design optimization of future spacecrafts as being coordinated by the Vehicle Analysis Branch where this research is being conducted.

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

    SciTech Connect

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

    2006-04-10

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

  12. Material properties and laser cutting of composites

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Chieh; Cheng, Wing

    Laser (Light Amplification by Stimulated Emission of Radiation) has been used successfully for many material cutting, drilling, metal welding and heat treating applications. However, laser cutting of polymer composites were attempted with varying degrees of success. Because composites are heterogeneous, the energy applied by laser could result in severe resin degradation before fibers were cut. In this study, cutting of glass, Kevlar, and graphite composites were evaluated based on their material properties and laser cutting parameters. A transient heat transfer analysis was used to determine the relative heat affected zones of these composites. Kevlar composites can be cut very well while graphite composites are difficult to cut. Though the cutting process is much more complicated in reality, the analysis provides a semi-quantitative perspective on the characteristics and limitations of laser cutting of different composites.

  13. Composite materials for space applications

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  14. Compositions and chemical bonding in ceramics by quantitative electron energy-loss spectrometry

    SciTech Connect

    Bentley, J.; Horton, L.L.; McHargue, C.J.; McKernan, S.; Carter, C.B.; Revcolevschi, A.; Tanaka, S.; Davis, R.F.

    1993-12-31

    Quantitative electron energy-loss spectrometry was applied to a range of ceramic materials at a spatial resolution of <5 nm. Analysis of Fe L{sub 23} white lines indicated a low-spin state with a charge transfer of {approximately}1.5 electrons/atom onto the Fe atoms implanted into (amorphized) silicon carbide. Gradients of 2 to 5% in the Co:O stoichiometry were measured across 100-nm-thick Co{sub 3}O{sub 4} layers in an oxidized directionally solidified CoO-ZrO{sub 2} eutectic, with the highest O levels near the ZrO{sub 2}. The energy-loss near-edge structures were dramatically different for the two cobalt oxides; those for CO{sub 3}O{sub 4} have been incorrectly ascribed to CoO in the published literature. Kinetically stabilized solid solubility occurred in an AlN-SiC film grown by low-temperature molecular beam epitaxy (MBE) on {alpha}(6H)-SiC, and no detectable interdiffusion occurred in couples of MBE-grown AlN on SiC following annealing at up to 1750C. In diffusion couples of polycrystalline AlN on SiC, interfacial 8H sialon (aluminum oxy-nitride) and pockets of Si{sub 3}N{sub 4}-rich {beta}{prime} sialon in the SiC were detected.

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

    PubMed

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

    2012-10-15

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

  16. Space processing of composite materials

    NASA Technical Reports Server (NTRS)

    Steurer, W. H.; Kaye, S.

    1975-01-01

    Materials and processes for the testing of aluminum-base fiber and particle composites, and of metal foams under extended-time low-g conditions were investigated. A wetting and dispersion technique was developed, based on the theory that under the absence of a gas phase all solids are wetted by liquids. The process is characterized by a high vacuum environment and a high temperature cycle. Successful wetting and dispersion experiments were carried out with sapphire fibers, whiskers and particles, and with fibers of silicon carbide, pyrolytic graphite and tungsten. The developed process and facilities permit the preparation of a precomposite which serves as sample material for flight experiments. Low-g processing consists then merely in the uniform redistribution of the reinforcements during a melting cycle. For the preparation of metal foams, gas generation by means of a thermally decomposing compound was found most adaptable to flight experiments. For flight experiments, the use of compacted mixture of the component materials limits low-g processing to a simple melt cycle.

  17. Compositional Analysis of Ternary and Binary Chemical Mixtures by Surface-Enhanced Raman Scattering at Trace Levels

    NASA Astrophysics Data System (ADS)

    Hou, Mengjing; Huang, Yu; Ma, Lingwei; Zhang, Zhengjun

    2015-11-01

    Surface-enhanced Raman scattering has been proven a powerful means in the fast detection and recognition of chemicals at trace levels, while quantitative analysis especially the compositional analysis of trace chemical mixtures remains a challenge. We report here a "triangle-rule" based on the principal component analysis (PCA) of surface-enhanced Raman scattering spectra, to calculate the composition of individual component of ternary chemical mixtures at trace levels, which can be simplified into the "balance-rule" for binary mixtures. We demonstrated the validity of the triangle-rule and balance-rule in estimating the composition of ternary and binary mixtures of methyl orange, methylene blue, and crystal violet with different molecular structures, and the validity for ternary and binary mixtures of three isomers of monochlorobiphenyl with very similar molecular structures. This idea might be also applicable to mixtures of more components at the trace levels.

  18. Reaching Europa's Surface: Erosion of the Viscous Lid by Compositional Plumes with Implications for Ocean-Surface Material Exchange

    NASA Astrophysics Data System (ADS)

    Allu Peddinti, D.; McNamara, A. K.

    2014-12-01

    The source of the intriguing surface chemistry of the icy moon, Europa has been widely debated. Of primary interest is the process of surface-ice-shell-ocean exchange of trace chemistry. Of particular astrobiological interest is the possible endogenic origin of the surface chemistry. The viscous lid atop the ice-shell poses a physical barrier for such a material exchange to occur. We have performed a computational study of thermochemical convection models to test the weakening of this viscous lid by warmer plumes of lower compositional density rising in the ice-shell. We modeled a two-phase convecting ice-ocean system with a low viscosity proxy fluid approximation for the liquid ocean. On achieving a stable convecting system, the newly frozen ice at the base of the warm ice plumes at the shell-ocean boundary is tracked and mapped as it is advected upwards by the rising plumes. The newly formed ice is prescribed a lower intrinsic density than the ambient ice to mimic the scenario where compositional contrasts in the ice-shell could exist. We then study how the rising compositional plumes incorporated with the low intrinsic density new ice can erode the stagnant lid at the top of the ice-shell. Several values of density contrast have been modeled to study any variability in their extent of erosion of the lid. The models show that in a convecting ice-ocean system, it is possible for less dense newly formed ice to incorporate into the convecting ice plumes and erode the lid over time. The results suggest that if oceanic trace chemistry were to be incorporated into the newly frozen ice at the ice-ocean interface, it could be possible for it to reach the surface by continual erosion of the viscous ice lid at the top of the shell. This presents a plausible scenario for surface detection of an endogenic chemical signature that could be a potential biosignature of subsurface life in Europa.

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

    PubMed Central

    Gao, Fei; Li, Fenghui; Tan, Jie; Yan, Jingping; Sun, Huiling

    2014-01-01

    The composition of the bacterial communities in the contents of the foregut and hindgut of the sea cucumber Apostichopus japonicus and in the ambient surface sediment was surveyed by 16S rRNA gene 454-pyrosequencing. A total of 188,623 optimized reads and 15,527 operational taxonomic units (OTUs) were obtained from the ten gut contents samples and four surface sediment samples. The sequences in the sediments, foregut contents, and hindgut contents were assigned to 38.0±4.7, 31.2±6.2 and 27.8±6.5 phyla, respectively. The bacterial richness and Shannon diversity index were both higher in the ambient sediments than in the gut contents. Proteobacteria was the predominant phylum in both the gut contents and sediment samples. The predominant classes in the foregut, hindgut, and ambient sediment were Holophagae and Gammaproteobacteria, Deltaproteobacteria and Gammaproteobacteria, and Gammaproteobacteria and Deltaproteobacteria, respectively. The potential probiotics, including sequences related to Bacillus, lactic acid bacteria (Lactobacillus, Lactococcus, and Streptococcus) and Pseudomonas were detected in the gut of A. japonicus. Principle component analysis and heatmap figure showed that the foregut, hindgut, and ambient sediment respectively harbored different characteristic bacterial communities. Selective feeding of A. japonicus may be the primary source of the different bacterial communities between the foregut contents and ambient sediments. PMID:24967593

  20. Bacterial community composition in the gut content and ambient sediment of sea cucumber Apostichopus japonicus revealed by 16S rRNA gene pyrosequencing.

    PubMed

    Gao, Fei; Li, Fenghui; Tan, Jie; Yan, Jingping; Sun, Huiling

    2014-01-01

    The composition of the bacterial communities in the contents of the foregut and hindgut of the sea cucumber Apostichopus japonicus and in the ambient surface sediment was surveyed by 16S rRNA gene 454-pyrosequencing. A total of 188,623 optimized reads and 15,527 operational taxonomic units (OTUs) were obtained from the ten gut contents samples and four surface sediment samples. The sequences in the sediments, foregut contents, and hindgut contents were assigned to 38.0±4.7, 31.2±6.2 and 27.8±6.5 phyla, respectively. The bacterial richness and Shannon diversity index were both higher in the ambient sediments than in the gut contents. Proteobacteria was the predominant phylum in both the gut contents and sediment samples. The predominant classes in the foregut, hindgut, and ambient sediment were Holophagae and Gammaproteobacteria, Deltaproteobacteria and Gammaproteobacteria, and Gammaproteobacteria and Deltaproteobacteria, respectively. The potential probiotics, including sequences related to Bacillus, lactic acid bacteria (Lactobacillus, Lactococcus, and Streptococcus) and Pseudomonas were detected in the gut of A. japonicus. Principle component analysis and heatmap figure showed that the foregut, hindgut, and ambient sediment respectively harbored different characteristic bacterial communities. Selective feeding of A. japonicus may be the primary source of the different bacterial communities between the foregut contents and ambient sediments. PMID:24967593

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

    NASA Astrophysics Data System (ADS)

    Williams, Richard L.; Yore, Larry D.

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

  2. Material nonlinear analysis of composites

    NASA Astrophysics Data System (ADS)

    Kwon, Y. W.

    1991-05-01

    A three dimensional analysis model was developed for the material nonlinear analysis of continuous fiber reinforced composite plates. The respective yield criterion and flow rule or each constituent, namely fiber or matrix, can be used in the model instead of those for the globally smeared anisotropic material. The respective stresses occurring on each constitutent can also be obtained directly from the present model. The model was degenerated into a plate bending analysis model and a two dimensional analysis model. A finite element formulation was derived from the analysis model. Application of the present analysis model along with the finite element formulation to the material nonlinear analyses of composites provided good solutions. Some examples of composite plate bending were solved using the present formulation.

  3. Lightweight, Thermally Conductive Composite Material

    NASA Technical Reports Server (NTRS)

    Sharp, G. Richard; Loftin, Timothy A.

    1990-01-01

    Aluminum reinforced with carbon fibers superior to copper in some respects. Lightweight composite material has high thermal conductivity. Consists of aluminum matrix containing graphite fibers, all oriented in same direction. Available as sheets, tubes, and bars. Thermal conductivity of composite along fibers rises above that of pure copper over substantial range of temperatures. Graphite/aluminum composite useful in variety of heat-transfer applications in which reduction of weight critical. Used to conduct heat in high-density, high-speed integrated-circuit packages for computers and in base plates for electronic equipment. Also used to carry heat away from leading edges of wings in high-speed airplanes.

  4. Chemical composition and vasorelaxant effect induced by the essential oil of Lippia alba (Mill.) N.E. Brown. (Verbenaceae) in rat mesenteric artery

    PubMed Central

    Maynard, Luana G.; Santos, Ktia C.; Cunha, Patrcia S.; Barreto, Andr S.; Peixoto, Magna G.; Arrigoni-Blank, Ftima; Blank, Arie F.; Alves, Pricles B.; Bonjardin, Leonardo R.; Santos, Mrcio R.V.

    2011-01-01

    Objectives: To investigate the chemical composition and vasorelaxant effect of the essential oil of Lippia alba (EOLA) in rat mesenteric artery. Material and Methods: Chemical composition of EOLA was investigated by gas chromatography-mass spectrometry (GC/MS). Vasorelaxant effect was evaluated in vitro in rat superior mesenteric artery rings. Results: GC/MS analysis revealed the presence of 19 compounds, with geranial (48.58%) and neral (35.42%) being the major constituents. In intact rings precontracted with phenylephrine (Phe: 1 ?M), EOLA (100-1000 ?g/mL) induced relaxation, where the maximal effect (Emax) was 110.8 10.8%. This effect was not modified after endothelium removal (Emax = 134.8 16.5%), after tetraethylammonium (TEA) (Emax = 117.2 4.96%), or in rings precontracted with KCl (80 mM) (Emax = 112.6 6.70%). In addition, EOLA was able to inhibit the contraction caused by CaCl2 and produced a small but significant (P<0.05) additional effect (from 70.5 3.4 to 105.3 13.5%, n = 5) on the maximal relaxation of nifedipine (NIF: 10 ?M). Conclusions: The results demonstrated that EOLA induces endothelium-independent vasorelaxation, which appears to be caused, at least in part, by blocking Ca2+ influx through voltage-operated Ca2+ channels. PMID:22144776

  5. Chemical Composition of Fresh and Aged Biochars

    NASA Astrophysics Data System (ADS)

    Cooper, W. T.; Hamdan, R.; Mukherjee, A.; Zimmerman, A. R.

    2014-12-01

    It is possible to manipulate the chemical and physical properties of pyrogenic organic matter ('black carbon' or 'biochar') during its production and tailor its composition for intended environmental management applications. In this study biochars made from grass (Tripsacum floridanum), oak (Quercus lobata), and pine (Pinus taeda) at 250 ºC in air and 400 and 650 ºC under N2 were characterized by solid state 13C-NMR spectroscopy and desorption atmospheric pressure photoionization mass spectrometry. Among the biochars produced, those originating from pine showed distinct characteristics, with greater amounts of oxygenated aromatic clusters after low temperature combustion and more condensed aromatic clusters after higher temperature pyrolysis. Although a mixture of small and large aromatic clusters occurred across the temperature profile, cluster size increased and functionality decreased with increasing combustion temperature (Figure 1). At medium and high temperatures, aromatic clusters of up to 60- carbon aromatic rings inter-connected with small chains dominated the biochars examined. These structures are intermediate in size between the linearly condensed structures and the predominantly condensed aromatic clusters proposed in earlier studies. Field aging of the pure biochars for 15 months decreased the total acid functional group content as determined by Boehm titration, but solid-state 13C-NMR analyses suggested the creation and transformation of a range of functional groups via leaching, oxidation, and addition of microbially-produced organic matter. Similar trends were observed when the biochars were mixed with soils, suggesting that the same biochar aging processes occurred in the soil environment. These findings demonstrate that biochar transformations occur over time through a multitude of processes that are both biochar and soil type-dependent.

  6. Correlation of rocket propulsion fuel properties with chemical composition using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry followed by partial least squares regression analysis.

    PubMed

    Kehimkar, Benjamin; Hoggard, Jamin C; Marney, Luke C; Billingsley, Matthew C; Fraga, Carlos G; Bruno, Thomas J; Synovec, Robert E

    2014-01-31

    There is an increased need to more fully assess and control the composition of kerosene-based rocket propulsion fuels such as RP-1. In particular, it is critical to make better quantitative connections among the following three attributes: fuel performance (thermal stability, sooting propensity, engine specific impulse, etc.), fuel properties (such as flash point, density, kinematic viscosity, net heat of combustion, and hydrogen content), and the chemical composition of a given fuel, i.e., amounts of specific chemical compounds and compound classes present in a fuel as a result of feedstock blending and/or processing. Recent efforts in predicting fuel chemical and physical behavior through modeling put greater emphasis on attaining detailed and accurate fuel properties and fuel composition information. Often, one-dimensional gas chromatography (GC) combined with mass spectrometry (MS) is employed to provide chemical composition information. Building on approaches that used GC-MS, but to glean substantially more chemical information from these complex fuels, we recently studied the use of comprehensive two dimensional (2D) gas chromatography combined with time-of-flight mass spectrometry (GCGC-TOFMS) using a "reversed column" format: RTX-wax column for the first dimension, and a RTX-1 column for the second dimension. In this report, by applying chemometric data analysis, specifically partial least-squares (PLS) regression analysis, we are able to readily model (and correlate) the chemical compositional information provided by use of GCGC-TOFMS to RP-1 fuel property information such as density, kinematic viscosity, net heat of combustion, and so on. Furthermore, we readily identified compounds that contribute significantly to measured differences in fuel properties based on results from the PLS models. We anticipate this new chemical analysis strategy will have broad implications for the development of high fidelity composition-property models, leading to an improved approach to fuel formulation and specification for advanced engine cycles. PMID:24411093

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  8. Material properties of PDLC composites

    NASA Astrophysics Data System (ADS)

    Klosowicz, Stanislaw J.

    1996-04-01

    Liquid crystal composites, i.e., two phase polymer-liquid crystal systems, are very interesting from a scientific and application point of view. Amongst them the best known is PDLC (polymer dispersed liquid crystal) structure. In this material liquid crystal (LC) droplets, diameter of 0.1 - 10 micrometer are embedded in a polymer matrix. PDLC composites are used for construction of new information displays, image projectors and optical devices. In the presented work essential material requirements for PDLC are given from an application point of view. They concern mainly well-known electro-optical effect of electrically induced transmittance. The examples of experimental results are also presented.

  9. Impact response of composite materials

    NASA Technical Reports Server (NTRS)

    Tiwari, S. N.; Srinivasan, K.

    1991-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    PubMed Central

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

    2014-01-01

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

  12. Delamination growth in composite materials

    NASA Technical Reports Server (NTRS)

    Gillespie, J. W., Jr.; Carlson, L. A.; Pipes, R. B.; Rothschilds, R.; Trethewey, B.; Smiley, A.

    1985-01-01

    Research related to growth of an imbedded through-width delamination (ITWD) in a compression loaded composite structural element is presented. Composites with widely different interlaminar fracture resistance were examined, viz., graphite/epoxy (CYCOM 982) and graphite/PEEK (APC-2). The initial part of the program consisted of characterizing the material in tension, compression and shear mainly to obtain consistent material properties for analysis, but also as a check of the processing method developed for the thermoplastic APC-2 material. The characterization of the delamination growth in the ITWD specimen, which for the unidirectional case is essentially a mixed Mode 1 and 2 geometry, requires verified mixed-mode growth criteria for the two materials involved. For this purpose the main emphasis during this part of the investigation was on Mode 1 and 2 fracture specimens, namely the Double Cantilever Beam (DCB) and End Notched Flexure (ENF) specimens.

  13. Robotic systems for the determination of the composition of solar system materials by means of fireball spectroscopy

    NASA Astrophysics Data System (ADS)

    Madiedo, José M.

    2014-12-01

    The operation of the automated CCD spectrographs deployed by the University of Huelva at different observatories along Spain is described. These devices are providing information about the chemical nature of meteoroids ablating in the atmosphere. In this way, relevant physico-chemical data are being obtained from the ground for materials coming from different bodies in the Solar System (mainly asteroids and comets). The spectrographs, which work in a fully autonomous way by means of software developed for this purpose, are being employed to perform a systematic fireball spectroscopic campaign since 2006. Some examples of meteor spectra obtained by these devices are also presented and discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  15. Insight into acid-base nucleation experiments by comparison of the chemical composition of positive, negative, and neutral clusters.

    PubMed

    Bianchi, Federico; Praplan, Arnaud P; Sarnela, Nina; Dommen, Josef; Krten, Andreas; Ortega, Ismael K; Schobesberger, Siegfried; Junninen, Heikki; Simon, Mario; Trstl, Jasmin; Jokinen, Tuija; Sipil, Mikko; Adamov, Alexey; Amorim, Antonio; Almeida, Joao; Breitenlechner, Martin; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Kangasluoma, Juha; Keskinen, Helmi; Kim, Jaeseok; Kirkby, Jasper; Laaksonen, Ari; Lawler, Michael J; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petj, Tuukka; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Tom, Antnio; Virtanen, Annele; Viisanen, Yrj; Williamson, Christina; Wimmer, Daniela; Winkler, Paul M; Ye, Penglin; Curtius, Joachim; Kulmala, Markku; Worsnop, Douglas R; Donahue, Neil M; Baltensperger, Urs

    2014-12-01

    We investigated the nucleation of sulfuric acid together with two bases (ammonia and dimethylamine), at the CLOUD chamber at CERN. The chemical composition of positive, negative, and neutral clusters was studied using three Atmospheric Pressure interface-Time Of Flight (APi-TOF) mass spectrometers: two were operated in positive and negative mode to detect the chamber ions, while the third was equipped with a nitrate ion chemical ionization source allowing detection of neutral clusters. Taking into account the possible fragmentation that can happen during the charging of the ions or within the first stage of the mass spectrometer, the cluster formation proceeded via essentially one-to-one acid-base addition for all of the clusters, independent of the type of the base. For the positive clusters, the charge is carried by one excess protonated base, while for the negative clusters it is carried by a deprotonated acid; the same is true for the neutral clusters after these have been ionized. During the experiments involving sulfuric acid and dimethylamine, it was possible to study the appearance time for all the clusters (positive, negative, and neutral). It appeared that, after the formation of the clusters containing three molecules of sulfuric acid, the clusters grow at a similar speed, independent of their charge. The growth rate is then probably limited by the arrival rate of sulfuric acid or cluster-cluster collision. PMID:25406110

  16. Chemical composition, vitamin E content, lipid oxidation, colour and cooking losses in meat from Tudanca bulls finished on semi-extensive or intensive systems and slaughtered at 12 or 14 months.

    PubMed

    Humada, M J; Sañudo, C; Serrano, E

    2014-02-01

    The effects of production system (SE: pasture based vs. IN: concentrate based) and slaughter age (12 vs. 14 months) on chemical composition, vitamin E and myoglobin contents, lipid oxidation at 0, 3 and 6 days of display, colour and cooking losses at 2 and 7 days postmortem from thirty-three Tudanca calves were studied. SE animals showed lower IMF and greater vitamin E contents (1.2 vs. 2.9% and 4.1 vs. 1.8 μg/g, respectively). Thiobarbituric acid reactive substances (TBARS) increased (p ≤ 0.001) with display time and was greater in the IN system. After 6 days display, IN animals presented twofold TBARS values (1.4 vs. 0.8 mg malonaldehyde/kg meat). At 7 days postmortem, SE groups presented greater (p ≤ 0.05) L* and lower (p ≤ 0.05) b* and H° than IN groups. Myoglobin increased with age (3.4 to 3.9 mg/g meat), but differences (p ≤ 0.05) on a* and C* values were observed only between 12 and 14 months at 2 days postmortem. PMID:24211548

  17. Shifting material source of Chinese Loess since ~2.7 Ma reflected by Sr isotopic composition.

    PubMed

    Zhang, Wenfang; Chen, Jun; Li, Gaojun

    2015-01-01

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

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

    PubMed Central

    Zhang, Wenfang; Chen, Jun; Li, Gaojun

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Zhang, Wenfang; Chen, Jun; Li, Gaojun

    2015-05-01

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

  20. Chemical Composition of Micrometer-Sized Filaments in an Aragonite Host by a Miniature Laser Ablation/Ionization Mass Spectrometer.

    PubMed

    Tulej, Marek; Neubeck, Anna; Ivarsson, Magnus; Riedo, Andreas; Neuland, Maike B; Meyer, Stefan; Wurz, Peter

    2015-08-01

    Detection of extraterrestrial life is an ongoing goal in space exploration, and there is a need for advanced instruments and methods for the detection of signatures of life based on chemical and isotopic composition. Here, we present the first investigation of chemical composition of putative microfossils in natural samples using a miniature laser ablation/ionization time-of-flight mass spectrometer (LMS). The studies were conducted with high lateral (?15??m) and vertical (?20-200?nm) resolution. The primary aim of the study was to investigate the instrument performance on micrometer-sized samples both in terms of isotope abundance and element composition. The following objectives had to be achieved: (1) Consider the detection and calculation of single stable isotope ratios in natural rock samples with techniques compatible with their employment of space instrumentation for biomarker detection in future planetary missions. (2) Achieve a highly accurate chemical compositional map of rock samples with embedded structures at the micrometer scale in which the rock matrix is easily distinguished from the micrometer structures. Our results indicate that chemical mapping of strongly heterogeneous rock samples can be obtained with a high accuracy, whereas the requirements for isotope ratios need to be improved to reach sufficiently large signal-to-noise ratio (SNR). PMID:26247475

  1. Chemical compatibility of cartridge materials

    NASA Technical Reports Server (NTRS)

    Wilcox, Roy C.; Zee, R. H.

    1991-01-01

    This twelve month progress report deals with the chemical compatibility of semiconductor crystals grown in zero gravity. Specifically, it studies the chemical compatibility between TZM, a molybdenum alloy containing titanium and zirconium, and WC 103, a titanium alloy containing Niobium and Hafnium, and Gallium arsenide (GaAs) and Cadmium Zinc Tellurite (CdZnTe). Due to the health hazards involved, three approaches were used to study the chemical compatibility between the semiconductor and cartridge materials: reaction retort, thermogravimetric analysis, and bulk cylindrical cartridge containers. A scanning electron microscope with an energy dispersive X-ray analyzer was used to examine all samples after testing. The first conclusion drawn is that reaction rates with TZM were not nearly as great as they were with WC 103. Second, the total reaction between GaAs and WC 103 was almost twice that with TZM. Therefore, even though WC 103 is easier to fabricate, at least half of the cartridge thickness will be degraded if contact is made with one of the semiconductor materials leading to a loss of strength properties.

  2. The Effect of Chemical Functionalization on Mechanical Properties of Nanotube/Polymer Composites

    NASA Technical Reports Server (NTRS)

    Odegard, G. M.; Frankland, S. J. V.; Gates, T. S.

    2003-01-01

    The effects of the chemical functionalization of a carbon nanotube embedded in a nanotube/polyethylene composite on the bulk elastic properties are presented. Constitutive equations are established for both functionalized and non-functionalized nanotube composites systems by using an equivalent-continuum modeling technique. The elastic properties of both composites systems are predicted for various nanotube lengths, volume fractions, and orientations. The results indicate that for the specific composite material considered in this study, most of the elastic stiffness constants of the functionalized composite are either less than or equal to those of the non-functionalized composite.

  3. Welds in thermoplastic composite materials

    NASA Astrophysics Data System (ADS)

    Taylor, N. S.

    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.

  4. Composite materials inspection. [ultrasonic vibration holographic NDT

    NASA Technical Reports Server (NTRS)

    Erf, R. K.

    1974-01-01

    Investigation of the application requirements, advantages, and limitations of nondestructive testing by a technique of ultrasonic-vibration holographic-interferometry readout used in a production control facility for the inspection of a single product such as composite compressor blades. It is shown that, for the detection and characterization of disbonds in composite material structures, this technique may represent the most inclusive test method.

  5. Chemical microsensors based on polymer fiber composites

    NASA Astrophysics Data System (ADS)

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

    2005-05-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

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

    PubMed Central

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

    2014-01-01

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

  8. Evaluation of Microleakage of Silorane and Methacrylate Based Composite Materials in Class I Restorations by Using Two Different Bonding Techniques

    PubMed Central

    Alshetili, Mohsen S; Aldeyab, Sultan S

    2015-01-01

    Background: To evaluate the microleakage of silorane-based composite material (Filtek P90) with that of two homologous methacrylate-based composites materials (Filtek Z250 and Filtek Z250 XT), by using two different bonding techniques. Materials and Methods: Sixty extracted human maxillary first premolars prepared for standardized Class I cavities (4 mm × 2 mm × 2 mm) were randomly divided into three groups. Group A (n = 20) was filled with Filtek Z250 (Methacrylate) using single bond universal total etching technique, Group B (n = 20) was filled with Filtek Z250 XT (Methacrylate) using single bond universal self-etching technique and Group C (n = 20) restored with Filtek P90 (Silorane) with dedicated two-step self-etching prime and bond adhesive system (P90 system adhesive). Teeth were subjected to thermocycling regime (500×, 5-55°C), and dye penetration by immersing in 2% methylene blue for 24 h. Tooth sectioning was performed, and extent of the dye penetration was scored based on dye penetration scale to evaluate the microleakage. Statistical analysis included descriptive statistics and inferential statistics of Kruskal–Wallis test to compare the mean ranks between groups. Results: There was no significant difference observed for microleakage among the three composite materials tested in the present study. However, the cavities restored with silorane (Filtek P90) based composite displayed higher microleakage than the Filtek Z250, Z250 XT. Conclusion: All the restorative systems tested in this study exhibited microleakage, but the silorane technology showed more microleakage when compared to the methacrylate-based composite systems. PMID:26668473

  9. Si-C composites synthesized by using Si nanoparticles and carboxymethyl cellulose as anode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Koo, Jeong-Boon; Jang, Bo-Yun; Han, Kyoo-Seung

    2015-11-01

    Silicon-carbon (Si-C) composites with various weight ratios were prepared through heat treatment of water-soluble carboxymethyl cellulose (CMC) with Si nanoparticles synthesized by using an inductively-coupled plasma. Microstructures of the Si-C composites were thoroughly investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. The results indicate that we obtained a micro-sized Si-C composite with homogeneously-distributed crystalline Si nanoparticles in an amorphous C-matrix. Pores, which were due to the volatilization of CO2 from CMC during heat treatment, was detected when the concentration of carbon was increased. The electrochemical properties of those Si-C composites for use as anode materials in lithium-ion batteries (LIBs) were also investigated. The C-matrix enhanced the capacity retention, as well as the rate capability of Si nanoparticles, due to the dense and homogeneous microstructures of the composite. The Si-C composites (7:3 weight ratio) retained a reversible capacity of > 1,000 mAh/g with a capacity retention of 88.9% even after 100 cycles. The reversible capacity ratio at a 1.5 C-rate was about 80% as compared with that at a 0.1 C-rate.

  10. Date fruit: chemical composition, nutritional and medicinal values, products.

    PubMed

    Tang, Zhen-Xing; Shi, Lu-E; Aleid, Salah M

    2013-08-15

    Date fruit has served as a staple food in the Arab world for centuries. Worldwide production of date fruit has increased almost threefold over the last 40 years, reaching 7.68 million tons in 2010. Date fruit can provide many essential nutrients and potential health benefits to the consumer. Date fruit goes through four ripening stages named kimri, khalal, rutab and tamer. The main chemical components of date fruit include carbohydrates, dietary fibre, enzymes, protein, fat, minerals, vitamins, phenolic acids and carotenoids. The chemical composition of date fruit varies according to ripening stage, cultivar, growing environment, postharvest conditions, etc. The nutritional and medicinal activities of date fruit are related to its chemical composition. Many studies have shown that date fruit has antioxidant, antimutagenic, anti-inflammatory, gastroprotective, hepatoprotective, nephroprotective, anticancer and immunostimulant activities. Various date fruit-based products such as date syrup, date paste, date juice and their derived products are available. Date by-products can be used as raw materials for the production of value-added products such as organic acids, exopolysaccharides, antibiotics, date-flavoured probiotic-fermented dairy produce, bakery yeasts, etc. In this paper the chemical composition and nutritional and medicinal values of date fruit as well as date fruit-based products are reviewed. PMID:23553505

  11. Composition and Chemical Variability of Ivoirian Xylopia staudtii Leaf Oil.

    PubMed

    Yapi, Thierry Acafou; Boti, Jean Brice; Ahibo, Antoine Coffy; Sutour, Sylvain; Bighelli, Ange; Casanova, Joseph; Tomi, Félix

    2015-06-01

    The chemical composition of a leaf oil sample from Ivoirian Xylopia staudtii Engler & Diels (Annonaceae) has been investigated by a combination of chromatographic [GC(RI)] and spectroscopic (GC-MS, 13C NMR) techniques. Thirty-five components that accounted for 91.8% of the whole composition have been identified. The oil composition was dominated by the furanoguaiadienes furanoguaia-1,4-diene (39.0%) and furanoguaia-1,3-diene(7.5%), and by germacrene D (17.5%). The composition of twelve other leaf oil samples demonstrated qualitative homogeneity, but quantitative variability. Indeed, the contents of the major components varied substantially: furanoguaia-1,4-diene (24.7-51.7%) and germacrene D (5.9-24.8%). The composition of X. staudtii leaf oil is close to that of X. rubescens leaf oil but varied drastically from those of the essential oils isolated from other Xylopia species. 13C NMR spectroscopy appeared as a powerful and complementary tool for analysis of sesquiterpene-rich essential oils. PMID:26197551

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

    SciTech Connect

    Taga, Raijeli L.; Ng, Jack; Zheng Jiajia; Huynh, Trang; Noller, Barry; Harris, Hugh H.

    2010-06-23

    X-ray absorption spectroscopy (XAS) provides a direct means for measuring lead chemical forms in complex samples. In this study, XAS was used to identify the presence of plumbojarosite (PbFe{sub 6}(SO{sub 4}){sub 4}(OH){sub 12}) by lead L{sub 3}-edge XANES spectra in mine waste from a small gold mining operation in Fiji. The presence of plumbojarosite in tailings was confirmed by XRD but XANES gave better resolution. The potential for human uptake of Pb from tailings was measured using a physiologically based extract test (PBET), an in-vitro bioaccessibility (BAc) method. The BAc of Pb was 55%. Particle size distribution of tailings indicated that 40% of PM{sub 10} particulates exist which could be a potential risk for respiratory effects via the inhalation route. Food items collected in the proximity of the mine site had lead concentrations which exceed food standard guidelines. Lead within the mining lease exceeded sediment guidelines. The results from this study are used to investigate exposure pathways via ingestion and inhalation for potential risk exposure pathways of Pb in that locality. The highest Pb concentration in soil and tailings was 25,839 mg/kg, exceeding the Australian National Environment Protection Measure (NEPM) soil health investigation levels.

  13. Method of making a composite refractory material

    DOEpatents

    Morrow, M.S.; Holcombe, C.E.

    1995-09-26

    A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000 C to form a composite refractory material.

  14. Acoustic emission monitoring of polymer composite materials

    NASA Technical Reports Server (NTRS)

    Bardenheier, R.

    1981-01-01

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

  15. Composite materials with improved phyllosilicate dispersion

    DOEpatents

    Chaiko, David J.

    2004-09-14

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

  16. Method of making a composite refractory material

    DOEpatents

    Morrow, Marvin S. (Kingston, TN); Holcombe, Cressie E. (Knoxville, TN)

    1995-01-01

    A composite refractory material is prepared by combining boron carbide with furan resin to form a mixture containing about 8 wt. % furan resin. The mixture is formed into a pellet which is placed into a grit pack comprising an oxide of an element such as yttrium to form a sinterable body. The sinterable body is sintered under vacuum with microwave energy at a temperature no greater than 2000.degree. C. to form a composite refractory material.

  17. Investigation of composition and chemical state of elements in iron boride by the method of X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Alyoshin, V. G.; Kharlamov, A. I.; Prokopenko, V. M.

    1981-06-01

    The composition and chemical state of iron and boron in the surface layer of iron boride under different kinds of pretreatment of samples have been investigated by the method of X-ray photo-electron spectroscopy. It has been found that in the initial sample there is oxygen chemically combined with iron and boron atoms. Upon heating (450C) in hydrogen, in argon, and in vacuo there occurs removal of oxygen only from iron atoms (no pure iron was found to be formed). Boron oxidizes and there probably appears a new surface combination of boron with oxygen in which the bonding energy of 1 s electrons is higher than that in B 2O 3. Treatment of the iron boride surface with argon ions and with protons ensures uniform removal of oxygen from iron and boron atoms. It has been found that thermal treatment of iron boride leads to depletion of iron atoms from the sample surface layer, and pickling with argon ions and with protons leads to strong enrichment. Iron boride samples subjected to Ar + and H + bombardment tend to undergo significant oxidation when subsequently exposed to air at room temperature.

  18. Gaseous composition measured by a chemical ionization mass spectrometer in fresh and aged ship plumes

    NASA Astrophysics Data System (ADS)

    Faxon, Cameron; Psichoudaki, Magda; Kuuluvainen, Heino; Hallquist, sa; Thomson, Erik; Pettersson, Jan; Hallquist, Mattias

    2015-04-01

    The port of Gothenburg is the largest port of the Nordic countries with numerous ships calling the port daily. The ship exhausts contain numerous pollutants including gases such as SO2 and NOx as well as particulate matter and soot. The exhaust also contains numerous organic compounds, a large fraction of which are unidentified. These organics are oxidized in the atmosphere producing more oxygenated and potentially less volatile compounds that may contribute to the secondary organic aerosol (SOA). This work focuses on the characterization of fresh gaseous species present in the exhaust plumes of the passing ships and also on their photochemical aging. Between 26 September and 12 November 2014 measurements were conducted at a sampling site located on a small peninsula at the entrance of Gothenburg's port. The campaign was divided in two periods. During the first period, the fresh plumes of the passing ships were measured through a main inlet. During the second period, the sample passed through the same inlet and was then introduced into a Potential Aerosol Mass (PAM) reactor. The PAM reactor uses UV lamps and high concentrations of oxidants (OH radicals and O3) to oxidize the organic species present in the plumes. The oxidation that takes place within the reactor can be equivalent to up to one week of atmospheric oxidation. Preliminary tests showed that the oxidation employed in the current camping corresponded to 3.4 days in the atmosphere. A Time-of-Flight Chemical Ionization Mass Spectrometer (ToF-CIMS) was employed to monitor the concentration of different organic species present in the fresh and aged plumes. Water (positive) and iodide (negative) ionization methods were employed were water was primarily used for fresh plumes (large fraction of non-polar compounds) while iodide was used for the aged plumes (primarily oxidised products). The H2O, O3 and SO2 concentrations inside the PAM chamber were monitored, and an organic tracer for OH exposure determination was also continuously measured. The dominant species concentrations of both fresh and aged ship plumes are presented and their emission factors are estimated from concurrent CO2 measurements.

  19. Chemical composition studies of flint with different origins

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  20. Schima superba outperforms other tree species by changing foliar chemical composition and shortening construction payback time when facilitated by shrubs

    PubMed Central

    Liu, Nan; Guo, Qinfeng; Ren, Hai; Sun, Zhongyu

    2016-01-01

    A 3.5-year field experiment was conducted in a subtropical degraded shrubland to assess how a nurse plant, the native shrub Rhodomyrtus tomentosa, affects the growth of the target trees Pinus elliottii, Schima superba, Castanopsis fissa, and Michelia macclurei, and to probe the intrinsic mechanisms from leaf chemical composition, construction cost (CC), and payback time aspects. We compared tree seedlings grown nearby shrub canopy (canopy subplots, CS) and in open space (open subplots, OS). S. superba in CS showed greater growth, while P. elliottii and M. macclurei were lower when compared to the plants grown in the OS. The reduced levels of high-cost compounds (proteins) and increased levels of low-cost compounds (organic acids) caused reduced CC values for P. elliottii growing in CS. While, the levels of both low-cost minerals and high-cost proteins increased in CS such that CC values of S. superba were similar in OS and CS. Based on maximum photosynthetic rates, P. elliottii required a longer payback time to construct required carbon in canopy than in OS, but the opposite was true for S. superba. The information from this study can be used to evaluate the potential of different tree species in the reforestation of subtropical degraded shrublands. PMID:26814426

  1. Schima superba outperforms other tree species by changing foliar chemical composition and shortening construction payback time when facilitated by shrubs.

    PubMed

    Liu, Nan; Guo, Qinfeng; Ren, Hai; Sun, Zhongyu

    2016-01-01

    A 3.5-year field experiment was conducted in a subtropical degraded shrubland to assess how a nurse plant, the native shrub Rhodomyrtus tomentosa, affects the growth of the target trees Pinus elliottii, Schima superba, Castanopsis fissa, and Michelia macclurei, and to probe the intrinsic mechanisms from leaf chemical composition, construction cost (CC), and payback time aspects. We compared tree seedlings grown nearby shrub canopy (canopy subplots, CS) and in open space (open subplots, OS). S. superba in CS showed greater growth, while P. elliottii and M. macclurei were lower when compared to the plants grown in the OS. The reduced levels of high-cost compounds (proteins) and increased levels of low-cost compounds (organic acids) caused reduced CC values for P. elliottii growing in CS. While, the levels of both low-cost minerals and high-cost proteins increased in CS such that CC values of S. superba were similar in OS and CS. Based on maximum photosynthetic rates, P. elliottii required a longer payback time to construct required carbon in canopy than in OS, but the opposite was true for S. superba. The information from this study can be used to evaluate the potential of different tree species in the reforestation of subtropical degraded shrublands. PMID:26814426

  2. Delamination growth in composite materials

    NASA Technical Reports Server (NTRS)

    Gillespie, J. W., Jr.; Carlsson, L. A.; Pipes, R. B.; Rothschilds, R.; Trethewey, B.; Smiley, A.

    1986-01-01

    The Double Cantilever Beam (DCB) and the End Notched Flexure (ENF) specimens are employed to characterize MODE I and MODE II interlaminar fracture resistance of graphite/epoxy (CYCOM 982) and graphite/PEEK (APC2) composites. Sizing of test specimen geometries to achieve crack growth in the linear elastic regime is presented. Data reduction schemes based upon beam theory are derived for the ENF specimen and include the effects of shear deformation and friction between crack surfaces on compliance, C, and strain energy release rate, G sub II. Finite element (FE) analyses of the ENF geometry including the contact problem with friction are presented to assess the accuracy of beam theory expressions for C and G sub II. Virtual crack closure techniques verify that the ENF specimen is a pure Mode II test. Beam theory expressions are shown to be conservative by 20 to 40 percent for typical unidirectional test specimen geometries. A FE parametric study investigating the influence of delamination length and depth, span, thickness and material properties on G sub II is presented. Mode I and II interlaminar fracture test results are presented. Important experimental parameters are isolated, such as precracking techniques, rate effects, and nonlinear load-deflection response. It is found that subcritical crack growth and inelastic materials behavior, responsible for the observed nonlinearities, are highly rate-dependent phenomena with high rates generally leading to linear elastic response.

  3. Finite Element Modeling of the Thermographic Inspection for Composite Materials

    NASA Technical Reports Server (NTRS)

    Bucinell, Ronald B.

    1996-01-01

    The performance of composite materials is dependent on the constituent materials selected, material structural geometry, and the fabrication process. Flaws can form in composite materials as a result of the fabrication process, handling in the manufacturing environment, and exposure in the service environment to anomalous activity. Often these flaws show no indication on the surface of the material while having the potential of substantially degrading the integrity of the composite structure. For this reason it is important to have available inspection techniques that can reliably detect sub-surface defects such as inter-ply disbonds, inter-ply cracks, porosity, and density changes caused by variations in fiber volume content. Many non-destructive evaluation techniques (NDE) are capable of detecting sub-surface flaws in composite materials. These include shearography, video image correlation, ultrasonic, acoustic emissions, and X-ray. The difficulty with most of these techniques is that they are time consuming and often difficult to apply to full scale structures. An NDE technique that appears to have the capability to quickly and easily detect flaws in composite structure is thermography. This technique uses heat to detect flaws. Heat is applied to the surface of a structure with the use of a heat lamp or heat gun. A thermographic camera is then pointed at the surface and records the surface temperature as the composite structure cools. Flaws in the material will cause the thermal-mechanical material response to change. Thus, the surface over an area where a flaw is present will cool differently than regions where flaws do not exist. This paper discusses the effort made to thermo-mechanically model the thermography process. First the material properties and physical parameters used in the model will be explained. This will be followed by a detailed discussion of the finite element model used. Finally, the result of the model will be summarized along with recommendations for future work.

  4. [Chemical composition of 11 varieties of sorghum (Sorghum vulgare) before and after popping the kernels].

    PubMed

    Tuna, E; Bressani, R

    1992-09-01

    The effect of the popping process on the chemical composition, on lysine and tryptophan and on the in vitro protein digestibility of eleven sorghum varieties was evaluated. The popping of the grain was conducted in a popcorn popper previous adjustment of conditions. There were statistically significant differences in chemical composition both, in the raw grain and in the processed grain. The chemical composition was affected by the process and with the exception of protein content, it reduced the content of ether extract (3.43 to 2.75%) and increased significantly the level of crude fiber (2.47 to 4.45%). The concentration of available lysine and of tryptophan in the raw grain was reduced significantly by the process, with lysine losses of 9 to 57% and for tryptophan of 26 to 64%. A decrease was also observed in amylose as percentage of starch. In a number of samples the popping process significantly reduced in vitro protein digestibility. PMID:1342163

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

    PubMed Central

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

    2015-01-01

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

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

    PubMed

    Rusi; Chan, P Y; Majid, S R

    2015-01-01

    The composite metal oxide electrode films were fabricated using ex situ electrodeposition method with further heating treatment at 300C. The obtained composite metal oxide film had a spherical structure with mass loading from 0.13 to 0.21 mg cm(-2). The structure and elements of the composite was investigated using X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The electrochemical performance of different composite metal oxides was studied by cyclic voltammetry (CV) and galvanostatic charge-discharge (CD). As an active electrode material for a supercapacitor, the Co-Mn composite electrode exhibits a specific capacitance of 285 Fg(-1) at current density of 1.85 Ag(-1) in 0.5 M Na2SO4 electrolyte. The best composite electrode, Co-Mn electrode was then further studied in various electrolytes (i.e., 0.5 M KOH and 0.5 M KOH/0.04 M K3Fe(CN) 6 electrolytes). The pseudocapacitive nature of the material of Co-Mn lead to a high specific capacitance of 2.2 x 10(3) Fg(-1) and an energy density of 309 Whkg(-1) in a 0.5 M KOH/0.04 M K3Fe(CN) 6 electrolyte at a current density of 10 Ag(-1). The specific capacitance retention obtained 67% of its initial value after 750 cycles. The results indicate that the ex situ deposited composite metal oxide nanoparticles have promising potential in future practical applications. PMID:26158447

  7. Energy absorption of composite materials

    NASA Technical Reports Server (NTRS)

    Farley, G. L.

    1983-01-01

    Results of a study on the energy absorption characteristics of selected composite material systems are presented and the results compared with aluminum. Composite compression tube specimens were fabricated with both tape and woven fabric prepreg using graphite/epoxy (Gr/E), Kevlar (TM)/epoxy (K/E) and glass/epoxy (Gl/E). Chamfering and notching one end of the composite tube specimen reduced the peak load at initial failure without altering the sustained crushing load, and prevented catastrophic failure. Static compression and vertical impact tests were performed on 128 tubes. The results varied significantly as a function of material type and ply orientation. In general, the Gr/E tubes absorbed more energy than the Gl/E or K/E tubes for the same ply orientation. The 0/ + or - 15 Gr/E tubes absorbed more energy than the aluminum tubes. Gr/E and Gl/E tubes failed in a brittle mode and had negligible post crushing integrity, whereas the K/E tubes failed in an accordian buckling mode similar to the aluminum tubes. The energy absorption and post crushing integrity of hybrid composite tubes were not significantly better than that of the single material tubes.

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

    NASA Astrophysics Data System (ADS)

    Yoon, Joonsung

    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.

  9. Chemical effects correlated to nitrogen content of iron nitride films observed in the Fe L-shell X-rays induced by 5-keV electrons

    NASA Astrophysics Data System (ADS)

    Hinrichs, R.; Bertol, A. P. L.; Jacobsen, S. D.; Castellano, G.; Vasconcellos, M. A. Z.

    2014-01-01

    Iron nitride thin films, produced by reactive magnetron sputtering, were characterized with grazing incidence X-ray diffraction, X-ray reflectometry, Rutherford backscattering spectrometry (RBS) and conversion electron Mssbauer spectroscopy. Their characteristic L-X-rays spectra, obtained with an electron microprobe analyzer equipped with a wavelength dispersive spectrometer, were compared to the spectrum of an iron standard. The spectra from the nitrides presented several chemical effects: change in the relative peak areas and shifts of the positions of the L?1,2 and the L?1 peaks (chemical shift). The change in relative peak areas, namely the ratio between the L?1 and the L?1,2 peaks, correlated well with the nitrogen content measured with RBS.

  10. Contraction Measurements of Dental Composite Material during Photopolymerization by a Fiber Optic Interferometric Method.

    NASA Astrophysics Data System (ADS)

    Arenas, Gustavo; Noriega, Sergio; Mucci, Veronica; Vallo, Claudia; Duchowicz, Ricardo

    2008-04-01

    In order to monitor the shrinkage generated by new composites during photopolymerization, we have implemented a fiber optic sensing method based on a Fizeau-type interferometric scheme. This simple, compact, non-invasive and self-calibrating system competes with both conventional and other high-resolution bulk interferometric techniques. Several stages of the curing process were characterized from sample interferograms, including photopolymerization inhibition, the onset and degree of sample shrinkage, as well as typical kinetic behaviour of photopolymerization of dimethacrylates monomers. Some complementary studies (temperature and transmission measurements) were performed to complete the kinetic scheme. A simple polymerization model was generated in order to discuss the main results.

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

    SciTech Connect

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

    2012-02-01

    In an attempt to mitigate the hazards associated with storing large quantities of reactive metal hydrides, polymer composite materials were synthesized and tested under simulated usage and accident conditions. The composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride. Composites with vinyl-containing siloxane oligomers were also polymerized with and without added styrene and divinyl benzene. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride reduced the inherent hydrogen storage capacity of the material. The composites were found to be initially effective at reducing the amount of heat released during oxidation. However, upon cycling the composites, the mitigating behavior was lost. While the polymer composites we investigated have mitigating potential and are physically robust, they undergo a chemical change upon cycling that makes them subsequently ineffective at mitigating heat release upon oxidation of the metal hydride. Acknowledgements The authors would like to thank the following people who participated in this project: Ned Stetson (U.S. Department of Energy) for sponsorship and support of the project. Ken Stewart (Sandia) for building the flow-through calorimeter and cycling test stations. Isidro Ruvalcaba, Jr. (Sandia) for qualitative experiments on the interaction of sodium alanate with water. Terry Johnson (Sandia) for sharing his expertise and knowledge of metal hydrides, and sodium alanate in particular. Marcina Moreno (Sandia) for programmatic assistance. John Khalil (United Technologies Research Corp) for insight into the hazards of reactive metal hydrides and real-world accident scenario experiments. Summary In an attempt to mitigate and/or manage hazards associated with storing bulk quantities of reactive metal hydrides, polymer composite materials (a mixture of a mitigating polymer and a metal hydride) were synthesized and tested under simulated usage and accident conditions. Mitigating the hazards associated with reactive metal hydrides during an accident while finding a way to keep the original capability of the active material intact during normal use has been the focus of this work. These composites were made by polymerizing vinyl monomers using free-radical polymerization chemistry, in the presence of the metal hydride, in this case a prepared sodium alanate (chosen as a representative reactive metal hydride). It was found that the polymerization of styrene and divinyl benzene could be initiated using AIBN in toluene at 70 degC. The resulting composite materials can be either hard or brittle solids depending on the cross-linking density. Thermal decomposition of these styrene-based composite materials is lower than neat polystyrene indicating that the chemical nature of the polymer is affected by the formation of the composite. The char-forming nature of cross-linked polystyrene is low and therefore, not an ideal polymer for hazard mitigation. To obtain composite materials containing a polymer with higher char-forming potential, siloxane-based monomers were investigated. Four vinyl-containing siloxane oligomers were polymerized with and without added styrene and divinyl benzene. Like the styrene materials, these composite materials exhibited thermal decomposition behavior significantly different than the neat polymers. Specifically, the thermal decomposition temperature was shifted approximately 100 degC lower than the neat polymer signifying a major chemical change to the polymer network. Thermal analysis of the cycled samples was performed on the siloxane-based composite materials. It was found that after 30 cycles the siloxane-containing polymer composite material has similar TGA/DSC-MS traces as the virgin composite material indicating that the polymer is physically intact upon cycling. Hydrogen capacity measurements revealed that addition of the polymer to the metal hydride in the form of a composite material reduced the inherent hydrogen storage capacity of the material. This reduction in capacity was observed to be independent of the amount of charge/discharge cycles except for the composites containing siloxane, which showed less of an impact on hydrogen storage capacity as it was cycled further. While the reason for this is not clear, it may be due to a chemically stabilizing effect of the siloxane on the metal hydride. Flow-through calorimetry was used to characterize the mitigating effectiveness of the different composites relative to the neat (no polymer) material. The composites were found to be initially effective at reducing the amount of heat released during oxidation, and the best performing material was the siloxane-containing composite which reduced the heat release to less than 50% of the value of the neat material. However, upon cycling the composites, all mitigating behavior was lost. The combined results of the flow-through calorimetry, hydrogen capacity, and thermogravimetric analysis tests lead to the proposed conclusion that while the polymer composites have mitigating potential and are physically robust under cycling, they undergo a chemical change upon cycling that makes them ineffective at mitigating heat release upon oxidation of the metal hydride.

  12. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... chemicals produced. 19.308 Section 19.308 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... Spirits Rules for Chemical Byproducts § 19.308 Spirits content of chemicals produced. All chemicals and chemical byproducts produced must be substantially free of spirits before being removed from...

  13. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... chemicals produced. 19.308 Section 19.308 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... Spirits Rules for Chemical Byproducts § 19.308 Spirits content of chemicals produced. All chemicals and chemical byproducts produced must be substantially free of spirits before being removed from...

  14. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... chemicals produced. 19.308 Section 19.308 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... Spirits Rules for Chemical Byproducts § 19.308 Spirits content of chemicals produced. All chemicals and chemical byproducts produced must be substantially free of spirits before being removed from...

  15. 27 CFR 19.308 - Spirits content of chemicals produced.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... chemicals produced. 19.308 Section 19.308 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND... Spirits Rules for Chemical Byproducts 19.308 Spirits content of chemicals produced. All chemicals and chemical byproducts produced must be substantially free of spirits before being removed from...

  16. Comparison of chemical composition and antibacterial activity of Nigella sativa seed essential oils obtained by different extraction methods.

    PubMed

    Kokoska, L; Havlik, J; Valterova, I; Sovova, H; Sajfrtova, M; Jankovska, I

    2008-12-01

    Nigella sativa L. seed essential oils obtained by hydrodistillation (HD), dry steam distillation (SD), steam distillation of crude oils obtained by solvent extraction (SE-SD), and supercritical fluid extraction (SFE-SD) were tested for their antibacterial activities, using the broth microdilution method and subsequently analyzed by gas chromatography and gas chromatography-mass spectrometry. The results showed that the essential oils tested differed markedly in their chemical compositions and antimicrobial activities. The oils obtained by HD and SD were dominated by p-cymene, whereas the major constituent identified in both volatile fractions obtained by SD of extracted oils was thymoquinone (ranging between 0.36 and 0.38 g/ml, whereas in oils obtained by HD and SD, it constituted only 0.03 and 0.05 g/ml, respectively). Both oils distilled directly from seeds showed lower antimicrobial activity (MICs > or = 256 and 32 microg/ml for HD and SD, respectively) than those obtained by SE-SD and SFE-SD (MICs > or = 4 microg/ml). All oil samples were significantly more active against gram-positive than against gram-negative bacteria. Thymoquinone exhibited potent growth-inhibiting activity against gram-positive bacteria, with MICs ranging from 8 to 64 microg/ml. PMID:19244901

  17. Chemical characterization of selected LDEF polymeric materials

    NASA Technical Reports Server (NTRS)

    Young, Philip R.; Slemp, Wayne S.

    1991-01-01

    Chemical characterization of selected polymeric materials which received exposure on the Long Duration Exposure Facility (LDEF) is reported. The specimens examined include silvered fluorinated ethylene propylene Teflon thermal blanket material, polysulfone, epoxy, polyimide matrix resin/graphite fiber reinforced composites, and several high performance polymer films. These specimens came from numerous LDEF locations, and thus received different environmental exposures. The results to date show no significant change at the molecular level in the polymer that survived exposure. Scanning electron and scanning tunneling microscopes show resin loss and a texturing of some specimens which resulted in a change in optical properties. The potential effect of a silicon-containing molecular contamination on these materials is addressed. The possibility of continued post-exposure degradation of some polymeric films is also proposed.

  18. Comparison of chemical composition of Aerva javanica seed essential oils obtained by different extraction methods.

    PubMed

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

    2013-07-01

    Aerva javanica (Burm.f.) Juss. ex Schult. seed essential oils were obtained by hydrodistillation (HD) and dry steam distillation (SD) extracting methods and analyzed by using gas chromatography-mass spectrometry(GC-MS). Twenty and eighteen components representing 90.5% and 95.6% of the seed essential oil were identified, using hydrodistillation and dry steam distillation, respectively. The major constituent identified from seed essential oil obtained by HD were heptacosane (25.4%), 3-allyl-6-methoxyphenol (14.1%), pentacosane (12.1%), 6,10,14-trimethyl-2-pentade-canone (7.9%), nonacosane (7.1%), tricosane (3.6%), ?-farnesene (3.5%), dodecanal (2.7%) and octacosane (2.1%). Whereas the major constituent identified from seed essential oil obtained by SD were heptacosane (41.4%), pentacosane (21.2%), nonacosane (14.8%), tricosane (6.3%), octacosane (4.2%) and tetracosane (3.0%). PMID:23811454

  19. Ultrastructure of dragonfly wing veins: composite structure of fibrous material supplemented by resilin.

    PubMed

    Appel, Esther; Heepe, Lars; Lin, Chung-Ping; Gorb, Stanislav N

    2015-10-01

    Dragonflies count among the most skilful of the flying insects. Their exceptional aerodynamic performance has been the subject of various studies. Morphological and kinematic investigations have showed that dragonfly wings, though being rather stiff, are able to undergo passive deformation during flight, thereby improving the aerodynamic performance. Resilin, a rubber-like protein, has been suggested to be a key component in insect wing flexibility and deformation in response to aerodynamic loads, and has been reported in various arthropod locomotor systems. It has already been found in wing vein joints, connecting longitudinal veins to cross veins, and was shown to endow the dragonfly wing with chordwise flexibility, thereby most likely influencing the dragonfly's flight performance. The present study revealed that resilin is not only present in wing vein joints, but also in the internal cuticle layers of veins in wings of Sympetrum vulgatum (SV) and Matrona basilaris basilaris (MBB). Combined with other structural features of wing veins, such as number and thickness of cuticle layers, material composition, and cross-sectional shape, resilin most probably has an effect on the vein's material properties and the degree of elastic deformations. In order to elucidate the wing vein ultrastructure and the exact localisation of resilin in the internal layers of the vein cuticle, the approaches of bright-field light microscopy, wide-field fluorescence microscopy, confocal laser-scanning microscopy, scanning electron microscopy and transmission electron microscopy were combined. Wing veins were shown to consist of up to six different cuticle layers and a single row of underlying epidermal cells. In wing veins of MBB, the latter are densely packed with light-scattering spheres, previously shown to produce structural colours in the form of quasiordered arrays. Longitudinal and cross veins differ significantly in relative thickness of exo- and endocuticle, with cross veins showing a much thicker exocuticle. The presence of resilin in the unsclerotised endocuticle suggests its contribution to an increased energy storage and material flexibility, thus to the prevention of vein damage. This is especially important in the highly stressed longitudinal veins, which have much lower possibility to yield to applied loads with the aid of vein joints, as the cross veins do. These results may be relevant not only for biologists, but may also contribute to optimise the design of micro-air vehicles. PMID:26352411

  20. Branch Content in Hybrid Materials using Small-Angle Scattering

    NASA Astrophysics Data System (ADS)

    Beaucage, Greg

    2005-03-01

    Inorganic/organic hybrid materials often display ramified mass- fractal structures characterized by primary particle size, aggregate size, and mass-fractal dimension. Physical properties, such as mechanical and dynamic mechanical properties and electrical conductivity (in carbon composites for instance), can not be predicted using only these structural features since such properties are intimately tied to the degree and type of branching as shown by Witten [1]. Witten suggested the use of the minimum dimension, or the related connectivity dimension, to calculate mechanical response in these hybrid systems. A viable technique to quantify the minimum dimension and connectivity dimension in hybrid materials has, until recently, been absent from the literature. This presentation will discuss the use of small-angle x-ray and neutron scattering to describe branch content in hybrid materials [2] and will outline an approach to use the minimum dimension and connectivity dimension to predict static and dynamic mechanical properties for hybrid materials based on structure [1, 3]. 1. Witten TA, Rubinstein M, Colby RH Reinforcement of Rubber by Fractal Aggregates J Phys II 3 (3): 367-383 (1993). 2. Beaucage G Determination of branch fraction and minimum dimension of mass-fractal aggregates Phys Rev E 70 (3): art. no. 031401 Part 1 (2004). 3. Kohls DJ, Beaucage G Rational design of reinforced rubber Curr Opin Solid St M 6 (3): 183-194 (2002).

  1. Pedagogical Content Knowledge in Teaching Material

    ERIC Educational Resources Information Center

    Saeli, Mara; Perrenet, Jacob; Jochems, Wim M. G.; Zwaneveld, Bert

    2012-01-01

    The scope of this article is to understand to what extent Computer Science teachers can find support for their Pedagogical Content Knowledge (PCK) in teaching material. We report the results of a study in which PCK is used as framework to develop a research instrument to examine three high school computer science textbooks, with special focus on

  2. Comparison of sodium content of workplace and homemade meals through chemical analysis and salinity measurements

    PubMed Central

    Shin, Eun-Kyung

    2014-01-01

    BACKGROUND/OBJECTIVES Most Koreans consume nearly 70-80% of the total sodium through their dishes. The use of a salinometer to measure salinity is recommended to help individuals control their sodium intake. The purpose of this study was to compare sodium content through chemical analysis and salinity measurement in foods served by industry foodservice operations and homemade meals. MATERIALS/METHODS Workplace and homemade meals consumed by employees in 15 cafeterias located in 8 districts in Daegu were collected and the sodium content was measured through chemical analysis and salinity measurements and then compared. The foods were categorized into 9 types of menus with 103 workplace meals and 337 homemade meals. RESULTS Workplace meals did not differ significantly in terms of sodium content per 100 g of food but had higher sodium content via chemical analysis in roasted foods per portion. Homemade meals had higher broth salt content and higher salt content by chemical analysis per 100 g of roasted foods and hard-boiled foods. One-dish workplace meals had higher salinity (P < 0.05), while homemade broths and stews had higher sodium content (P < 0.05 and P < 0.01, respectively). The sodium content per 100 g of foods was higher in one-dish workplace meals (P < 0.05) and in homemade broths and stews (P < 0.01 and P < 0.05, respectively). CONCLUSIONS The use of a salinometer may be recommended to estimate the sodium content in foods and control one's sodium intake within the daily intake target as a way to promote cooking bland foods at home. However, estimated and actual measured values may differ. PMID:25324937

  3. Fabrication of carbon nanofiber-reinforced aluminum matrix composites assisted by aluminum coating formed on nanofiber surface by in situ chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Ogawa, Fumio; Masuda, Chitoshi

    2015-01-01

    The van der Waals agglomeration of carbon nanofibers (CNFs) and the weight difference and poor wettability between CNFs and aluminum hinder the fabrication of dense CNF-reinforced aluminum matrix composites with superior properties. In this study, to improve this situation, CNFs were coated with aluminum by a simple and low-cost in situ chemical vapor deposition (in situ CVD). Iodine was used to accelerate the transport of aluminum atoms. The coating layer formed by the in situ CVD was characterized using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, Fourier transform-infrared spectroscopy, and x-ray photoelectron spectroscopy. The results confirmed that the CNFs were successfully coated with aluminum. The composites were fabricated to investigate the effect of the aluminum coating formed on the CNFs. The dispersion of CNFs, density, Vickers micro-hardness and thermal conductivity of the composites fabricated by powder metallurgy were improved. Pressure-less infiltration experiments were conducted to fabricate composites by casting. The results demonstrated that the wettability and infiltration were dramatically improved by the aluminum coating layer on CNFs. The aluminum coating formed by the in situ CVD technique was proved to be effective for the fabrication of CNF-reinforced aluminum matrix composites.

  4. Chemical composition, antimicrobial property and microencapsulation of Mustard (Sinapis alba) seed essential oil by complex coacervation.

    PubMed

    Peng, Chao; Zhao, Su-Qing; Zhang, Jun; Huang, Gui-Ying; Chen, Lan-Ying; Zhao, Feng-Yi

    2014-12-15

    In this study, the essential oil from mustard seed was isolated by simultaneous steam distillation and extraction (SDE) and analyzed by gas chromatography-mass spectrometry (GC-MS). Fourteen components were identified in the mustard seed essential oil with allyl isothiocyanate being the main component (71.06%). The essential oil has a broad-spectrum antimicrobial activity with inhibition zones and MIC values in the range of 9.68-15.57 mm and 128-512 μg/mL respectively. The essential oil was subsequently encapsulated in complex coacervation microcapsules with genipin, a natural water-soluble cross-linker. The optimum parameters for the hardening effectiveness of the genipin-hardened essential oil microcapsules were 8h at 40°C and pH 10.0 with a genipin concentration of 0.075 g/g gelatin. The genipin-hardened microcapsules had a particle size of mainly 5-10 μm and strong chemistry stability which is potential for its application in food preservation. PMID:25038712

  5. Microcrack Quantification in Composite Materials by a Neural Network Analysis of Ultrasound Spectral Data

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    Intra-ply microcracking in unlined composite pressure vessels can be very troublesome to detect and when linked through the thickness can provide leak paths that may hinder mission success. The leaks may lead to loss of pressure/propellant, increased risk of explosion and possible cryo-pumping into air pockets within the laminate. Ultrasonic techniques have been shown capable of detecting the presence of microcracking and in this work they are used to quantify the level of microcracking. Resonance ultrasound methods are utilized with artificial neural networks to build a microcrack prediction/measurement tool. Two networks are presented, one unsupervised to provide a qualitative measure of microcracking and one supervised which provides a quantitative assessment of the level of microcracking. The resonant ultrasound spectroscopic method is made sensitive to microcracking by tuning the input spectrum to the higher frequency (shorter wavelength) components allowing more significant interaction with the defects. This interaction causes the spectral characteristics to shift toward lower amplitudes at the higher frequencies. As the density of the defects increases more interactions occur and more drastic amplitude changes are observed. Preliminary experiments to quantify the level of microcracking induced in graphite/epoxy composite samples through a combination of tensile loading and cryogenic temperatures are presented. Both unsupervised (Kohonen) and supervised (radial basis function) artificial neural networks are presented to determine the measurable effect on the resonance spectrum of the ultrasonic data taken from the samples.

  6. Tough composite materials: Recent developments

    NASA Technical Reports Server (NTRS)

    Vosteen, L. F. (editor); Johnston, N. J. (editor); Teichman, L. A. (editor); Blankenship, C. P. (editor)

    1985-01-01

    The present volume broadly considers topics in composite fracture toughness and impact behavior characterization, composite system constituent properties and their interrelationships, and matrix systems' synthesis and characterization. Attention is given to the characterization of interlaminar crack growth in composites by means of the double cantilever beam specimen, the characterization of delamination resistance in toughened resin composites, the effect of impact damage and open holes on the compressive strength of tough resin/high strain fiber laminates, the effect of matrix and fiber properties on compression failure mechanisms and impact resistance, the relation of toughened neat resin properties to advanced composite mechanical properties, and constituent and composite properties' relationships in thermosetting matrices. Also treated are the effect of cross-link density on the toughening mechanism of elastomer-modified epoxies, the chemistry of fiber/resin interfaces, novel carbon fibers and their properties, the development of a heterogeneous laminating resin, solvent-resistant thermoplastics, NASA Lewis research in advanced composites, and opportunities for the application of composites in commercial aircraft transport structures.

  7. Optimization of chemical compositions in low-carbon Al-killed enamel steel produced by ultra-fast continuous annealing

    SciTech Connect

    Dong, Futao; Du, Linxiu; Liu, Xianghua; Xue, Fei

    2013-10-15

    The influence of Mn,S and B contents on microstructural characteristics, mechanical properties and hydrogen trapping ability of low-carbon Al-killed enamel steel was investigated. The materials were produced and processed in a laboratory and the ultra-fast continuous annealing processing was performed using a continuous annealing simulator. It was found that increasing Mn,S contents in steel can improve its hydrogen trapping ability which is attributed by refined ferrite grains, more dispersed cementite and added MnS inclusions. Nevertheless, it deteriorates mechanical properties of steel sheet. Addition of trace boron results in both good mechanical properties and significantly improved hydrogen trapping ability. The boron combined with nitrogen segregating at grain boundaries, cementite and MnS inclusions, provides higher amount of attractive hydrogen trapping sites and raises the activation energy for hydrogen desorption from them. - Highlights: We study microstructures and properties in low-carbon Al-killed enamel steel. Hydrogen diffusion coefficients are measured to reflect fish-scale resistance. Manganese improves hydrogen trapping ability but decrease deep-drawing ability. Boron improves both hydrogen trapping ability and deep-drawing ability. Both excellent mechanical properties and fish-scale resistance can be matched.

  8. Chemical provinces reveal Elysium Volcano's compositional evolution

    NASA Astrophysics Data System (ADS)

    Susko, D. A.; Karunatillake, S.; Wray, J. J.; Skok, J. R.; Hurowitz, J.; Ojha, L.; Judice, T.; Bently, R. O. J.

    2014-12-01

    Chemical provinces of Mars became definable[1-3] with the maps of elemental mass fractions generated with Mars Odyssey Gamma Ray Spectrometer (GRS) data[4,5]. Previous work highlighted the Elysium lava flow province as anomalous, with a depletion in K and Th relative to the average crust in the rest of Mars (ROM).[3] We characterize the elemental composition, geology, and geomorphology of the region to constrain the processes that have contributed to its evolution. We compare SE Elysium with its North West lava fields, advancing prior work on thermal evolution of the martian mantle.[6] Lava fields at both sites probably source from Elysium eruptions. Both show similar Si content, as well as a Ca-enrichment compared to ROM, consistent with prior models.[6,7] Nevertheless, the two fields are compositionally distinct from each other, with NW Elysium decisively depleted in Ca and Fe, but enriched in K and Th. Such distinctness, in elements that reflect magmatic fractionation, reveals the possibility that a single volcanic complex on Mars may evolve rapidly during the Amazonian era, causing variable flow compositions. Interestingly, a chemical province containing volcanics that is contemporaneous with Elysium, overlaps the Tharsis region.[3] Unlike Elysium, the K and Th distributions within Tharsis are indistinguishable from ROM. Meanwhile, the mass fraction signature in Tharsis is enriched in Cl and depleted in Si. Such contrast, in chemical anomalies between volcanic constructs of similar age, may indicate that the depletion of K and Th in SE Elysium did not arise from temporal evolution of the mantle. [1] Taylor, G. et al. Geology 38, 183-186, 2010 [2] Gasnault, O. et al. 207, 226-247, 2010 [3] Karunatillake, S. et al. J. Geophys. Res. 114, E12001, 2009 [4] Boynton, W. V. et al. J. Geophys. Res. 112, E12S99, 2007 [5] Feldman, W. C. et al. J. Geophys. Res. 109, E09006, 2004 [6] Baratoux, D. et al. Nature 472, 338-41, 2011 [7] Balta, J. et al. Geology 41, 1115-1118, 2013

  9. Grafting in cellulose - polystyrene composite materials

    SciTech Connect

    Trejo O`Reilly, J.A.; Cavaille, J.Y.; Dufresne, A.

    1995-12-01

    In order to evaluate the effect of the grafting of polystyrene on model cellulosic fibers, several composite materials were processed, (1) by simply dispersing microfibrils into a polystyrene matrix, (2) by dispersing the same fibers but modified by phenyl groups, (3) by grafting a functionalized polystyrene on the fibers surface and mixing with the matrix. The characterization of the coupling agent used has been performed by several techniques: FTIR, NMR, DSC and elemental analysis. Evidence of grafting onto the fibers surface was displayed by FTIR measurements and elemental analysis. All the composite materials were characterized by DSC, tensile tests and mechanical spectroscopy.

  10. Bioinspired porous octacalcium phosphate/silk fibroin composite coating materials prepared by electrochemical deposition.

    PubMed

    Yang, Ya; Wang, Hui; Yan, Feng-Yi; Qi, Yu; Lai, Yue-Kun; Zeng, Dong-Mei; Chen, Guoqiang; Zhang, Ke-Qin

    2015-03-18

    The biomimetic structure and composition of biomaterials are recognized as critical factors that determine their biological performance. A bioinspired nano-micro structured octacalcium phosphate (OCP)/silk fibroin (SF) composite coating on titanium was achieved through a mild electrochemically induced deposition method. Findings indicate that SF plays a critical role in constructing the unique biomimetic hierarchical structure of OCP/SF composite coating layers. In vitro cell culture tests demonstrate that the presence of OCP/SF composite coatings, with highly ordered and hierarchically porous structure, greatly enhance cellular responses. The coatings developed in this study have considerable potential for various hard tissue engineering and applications. PMID:25734421

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

    SciTech Connect

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

    2006-07-31

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

  12. Modification of cast aluminum-matrix composite materials by refractory nanoparticles

    NASA Astrophysics Data System (ADS)

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

    2009-02-01

    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.

  13. Property changes induced by the space environment in composite materials on LDEF: Solar array materials passive LDEF experiment A0171 (SAMPLE)

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Surface modifications to composite materials induced by long term exposure in low earth orbit (LEO) were dominated by atomic oxygen erosion and micrometeoroid and space debris impacts. As expected, calculated erosion rates were peculiar to material type and within the predicted order of magnitude. Generally, about one ply of the carbon fiber composites was eroded during the 70 month LDEF experiment. Matrix erosion was greater than fiber erosion and was more evident for a polysulfone matrix than for epoxy matrices. Micrometeoroid and space debris impacts resulted in small (less than 1mm) craters and splattered contaminants on all samples. Surfaces became more diffuse and darker with small increases in emissivity and absorption. Tensile strength decreased roughly with thickness loss, and epoxy matrices apparently became slightly embrittled, probably as a result of continued curing under UV and/or electron bombardment. However, changes in the ultimate yield stress of the carbon reinforced epoxy composites correlate neither with weave direction nor fiber type. Unexpected developments were the discovery of new synergistic effects of the space environment in the interaction of atomic oxygen and copious amounts of contamination and in the induced luminescence of many materials.

  14. The Chemical Composition of Maple Syrup

    ERIC Educational Resources Information Center

    Ball, David W.

    2007-01-01

    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.)

  15. Flaxseed hull: Chemical composition and antioxidant activity during development.

    PubMed

    Herchi, Wahid; Al Hujaili, Abdullah D; Sakouhi, Faouzi; Sebei, Khaled; Trabelsi, Hajer; Kallel, Habib; Boukhchina, Sadok

    2014-01-01

    Changes in the chemical composition and antioxidant activity of flaxseed hull during maturation were investigated. P129 hull variety was studied at four maturation stages (St1, St2, St3, and St4). Significant variation in proximate composition and flaxseed hull oil characteristics were observed. A significant increase in the carbohydrates content of the hull was observed during development. The main methyl esters were linolenic acid (48.95 - 51.52 %), oleic acid (20.27-23.41%) and linoleic acid (15.62-17.70%). The highest polyunsaturated fatty acids (PUFA) were found to be 67.14 % at the first stage of maturity (St1). Flaxseed hull oil was of good quality, containing an abundance of omega-3 essential fatty acids. The iodine value increased, while the saponification value of oil decreased during seed development. The decrease in ascorbic acid content was steady. The maximum level of total phenolic acid content (128.3 mg/100 g oil) was reached at 7 DAF. The antioxidant activity of oilseed was assessed by means of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay. Radical scavenging activity for green hull was 52.74% and mature hull was 69.32%. PMID:24919478

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

    SciTech Connect

    Bunkin, Aleksei F; Pershin, S M

    2010-05-26

    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.

  17. Chemical composition of Earth-like planets

    NASA Astrophysics Data System (ADS)

    Ronco, M. P.; Thiabaud, A.; Marboeuf, U.; Alibert, Y.; de Ela, G. C.; Guilera, O. M.

    2015-08-01

    Models of planet formation are mainly focused on the accretion and dynamical processes of the planets, neglecting their chemical composition. In this work, we calculate the condensation sequence of the different chemical elements for a low-mass protoplanetary disk around a solar-type star. We incorporate this sequence of chemical elements (refractory and volatile elements) in our semi-analytical model of planet formation which calculates the formation of a planetary system during its gaseous phase. The results of the semi-analytical model (final distributions of embryos and planetesimals) are used as initial conditions to develope N-body simulations that compute the post-oligarchic formation of terrestrial-type planets. The results of our simulations show that the chemical composition of the planets that remain in the habitable zone has similar characteristics to the chemical composition of the Earth. However, differences exist that can be associated to the dynamical environment in which they were formed.

  18. Energy absorption of composite material and structure

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1987-01-01

    Results are presented from a joint research program on helicopter crashworthiness conducted by the U.S. Army Aerostructures Directorate and NASA Langley. Through the ongoing research program an in-depth understanding has been developed on the cause/effect relationships between material and architectural variables and the energy-absorption capability of composite material and structure. Composite materials were found to be efficient energy absorbers. Graphite/epoxy subfloor structures were more efficient energy absorbers than comparable structures fabricated from Kevlar or aluminum. An accurate method of predicting the energy-absorption capability of beams was developed.

  19. Exposure Assessment of Chemicals from Packaging Materials

    NASA Astrophysics Data System (ADS)

    Poças, Maria De Fátima; Hogg, Timothy

    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).

  20. 3-D textile reinforcements in composite materials

    SciTech Connect

    Miravete, A.

    1999-11-01

    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.

  1. Nonmetallic materials and composites at low temperatures

    SciTech Connect

    Hartwig, G.; Evans, D.

    1982-01-01

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

  2. Chemical modeling of boron adsorption by humic materials using the constant capacitance model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The constant capacitance surface complexation model was used to describe B adsorption behavior on reference Aldrich humic acid, humic acids from various soil environments, and dissolved organic matter extracted from sewage effluents. The reactive surface functional groups on the humic materials wer...

  3. Correlation between biogas yield and chemical composition of energy crops.

    PubMed

    Dandikas, V; Heuwinkel, H; Lichti, F; Drewes, J E; Koch, K

    2014-12-01

    The scope of this study was to investigate the influence of the chemical composition of energy crops on biogas and methane yield. In total, 41 different plants were analyzed in batch test and their chemical composition was determined. For acid detergent lignin (ADL) content below 10% of total solids, a significant negative correlation for biogas and methane yields (r?-0.90) was observed. Based on a simple regression analysis, more than 80% of the sample variation can be explained through ADL. Based on a principal component analysis and multiple regression analysis, ADL and hemicellulose are suggested as suitable model variables for biogas yield potential predictions across plant species. PMID:25443623

  4. Selenium-assisted controlled growth of graphene-Bi2Se3 nanoplates hybrid Dirac materials by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Sun, Zhencui; Man, Baoyuan; Yang, Cheng; Liu, Mei; Jiang, Shouzhen; Zhang, Chao; Zhang, Jiaxin; Liu, Fuyan; Xu, Yuanyuan

    2016-03-01

    Se seed layers were used to synthesize the high-quality graphene-Bi2Se3 nanoplates hybrid Dirac materials via chemical vapor deposition (CVD) method. The morphology, crystallization and structural properties of the hybrid Dirac materials were characterized by SEM, EDS, Raman, XRD, AFM and HRTEM. The measurement results verify that the Se seed layer on the graphene surface can effectively saturate the surface dangling bonds of the graphene, which not only impel the uniform Bi2Se3 nanoplates growing along the horizontal direction but also can supply enough Se atoms to fill the Se vacancies. We also demonstrate the Se seed layer can effectively avoid the interaction of Bi2Se3 and the graphene. Further experiments testify the different Se seed layer on the graphene surface can be used to control the density of the Bi2Se3 nanoplates.

  5. Ecotoxicity and fungal deterioration of recycled polypropylene/wood composites: effect of wood content and coupling.

    PubMed

    Sudár, András; López, María J; Keledi, Gergely; Vargas-García, M Carmen; Suárez-Estrella, Francisca; Moreno, Joaquín; Burgstaller, Christoph; Pukánszky, Béla

    2013-09-01

    Recycled polypropylene (rPP) was recovered from an industrial shredder and composites were prepared with a relatively wide range of wood content and with two coupling agents, a maleated PP (MAPP) and a maleated ethylene-propylene-diene elastomer (MAEPDM). The mechanical properties of the composites showed that the coupling agents change structure only slightly, but interfacial adhesion quite drastically. The durability of the materials was determined by exposing them to a range of fungi and, ecotoxicity was studied on the aquatic organism Vibrio fischeri. The composites generally exhibit low acute toxicity, with values below the levels considered to have direct ecotoxic effect on aquatic ecosystems (<2 toxic units). Their toxicity to V. fischeri depended on the presence of the coupling agents with larger E50 values in 24-h aqueous extracts from composites containing MAPP or MAEPDM in comparison to composites without any coupling agent. Evaluation of resistance against fungal colonization and deterioration proved that wood facilitates fungal colonization. Fungi caused slight mass loss (below 3%) but it was not correlated with substantial deterioration in material properties. MAPP seems to be beneficial in the retention of mechanical properties during fungal attack. rPP/wood composites can be considered non-ecotoxic and quite durable, but the influence of wood content on resistance to fungal attack must be taken into account for materials intended for applications requiring long-term outdoor exposure. PMID:23769467

  6. Effect of incinerator bottom-ash composition on the mechanical behavior of backfill material.

    PubMed

    Lin, Chiou-Liang; Weng, Meng-Chia; Chang, Chih-Hung

    2012-12-30

    This study explores the influence of the chemical composition (SiO(2), CaO, Fe(2)O(3), and Al(2)O(3)) of incinerator bottom ash on its friction angle. Direct shear tests were performed to measure the strength of bottom ash with two distinctly different compositions. Then, an empirical equation was regressed to determine the correlation between each composition and the friction angle. The experimental results showed that the main constituent material of the incinerator bottom ash from general municipal wastes is SiO(2), and the friction angle is 48.04-52.66. The bottom ash from incineration plants treating both municipal wastes and general industrial wastes has a high content of iron-aluminum oxides, and its friction angle is 44.60-52.52. According to the multivariate regression analysis result, the friction angle of bottom ash of any composition is influenced mainly by the Fe(2)O(3) and Al(2)O(3) contents. This study used the friction angle of the bottom ash from four different incineration plants to validate the empirical equation, and found that the error between actual friction angles and the predicted values was-1.36% to 5.34%. Therefore, the regressed empirical equation in this study can be employed in engineering applications to preliminarily identify the backfill quality of incinerator bottom ash. PMID:23084273

  7. Assessment of space environment induced microdamage in toughened composite materials

    NASA Technical Reports Server (NTRS)

    Sykes, George F.; Funk, Joan G.; Slemp, Wayne S.

    1986-01-01

    The effects of simulated space environments on the microdamage in a series of commercially available toughened matrix composite systems was determined. Low-earth orbit (LEO) exposures were simulated by thermal cycling; geosynchronous orbit (GEO) exposures were simulated by electron irradiation plus thermal cycling. Material response was characterized by assessing the induced microcracking and its influence on chemical and mechanical property changes. All materials, including several advanced, tough thermoplastics microcracked when exposed to the simulated LEO environment except a 177 C cured single phase toughened epoxy composite. The GEO simulated environment produced microdamage in all materials. The results suggest that increased matrix toughness may not be the overriding factor leading to improved durability in the space environment.

  8. Chemical composition of fat and oil products

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fats and oils are an important dietary component, and contribute to the nutritional and sensory quality of foods. This chapter focuses on the chemical composition of fats and oils, and how these compositions affect the functional properties of fats and oils in foods. The focus will remain on the mos...

  9. CHEMICAL COMPOSITION OF SOYBEAN GENOTYPES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At the National Center for Soybean Research at EMBRAPA (Brazilian Agricultural Research Corporation), efforts are being done to increase soybean consumption in Brazil. Through the breeding of specialty soybean cultivars, BRS 155, which has reduced content of trypsin inhibitor; BRS 213, which is nul...

  10. Fungal degradation of fiber-reinforced composite materials

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  11. Gradient composite materials for artificial intervertebral discs.

    PubMed

    Migacz, Katarzyna; Chłopek, Jan; Morawska-Chochół, Anna; Ambroziak, Maciej

    2014-01-01

    Composites with the gradient of Young's modulus constitute a new group of biomimetic materials which affect the proper distribution of stresses between the implant and the bone. The aim of this article was to examine the mechanical properties of gradient materials based on carbon fibre-polysulfone composite, and to compare them to the properties of a natural intervertebral disc. Gradient properties were provided by different orientation or volume fraction of carbon fibres in particular layers of composites. The results obtained during in vitro tests displayed a good durability of the gradient materials put under long-term static load. However, the configuration based on a change in the volume fraction of the fibres seems more advantageous than the one based on a change of the fibres' orientation. The materials under study were designed to replace the intervertebral disc. The effect of Young's modulus of the material layers on the stress distribution between the tissue and the implant was analyzed and the biomimetic character of the gradient composites was stated. Unlike gradient materials, the pure polysulfone and the non-gradient composite resulted in the stress concentration in the region of nucleus pulposus, which is highly disadvantageous and does not occur in the stress distribution of natural intervertebral discs. PMID:25306938

  12. Characterization of SiC f/SiC and CNT/SiC composite materials produced by liquid phase sintering

    NASA Astrophysics Data System (ADS)

    Lee, J. K.; Lee, S. P.; Cho, K. S.; Byun, J. H.; Bae, D. S.

    2011-10-01

    This paper dealt with the microstructure and mechanical properties of SiC based composites reinforced with different reinforcing materials. The composites were fabricated using reinforcing materials of carbon nanotubes (CNT) and Tyranno Lox-M SiC chopped fibers. The volume fraction of carbon nanotubes was also varied in this composite system. An Al 2O 3-Y 2O 3 powder mixture was used as a sintering additive in the consolidation of the SiC matrix. The characterization of the composites was investigated by means of SEM and three point bending tests. These composites showed a dense morphology of the matrix region, by the creation of a secondary phase. The composites reinforced with SiC chopped fibers possessed a flexural strength of about 400 MPa at room temperature. The flexural strength of the carbon nanotubes composites had a tendency to decrease with increased volume fraction of the reinforcing material.

  13. Chemical composition and selected mechanical properties of Al-Zn alloy modified in plasma conditions by RF CVD

    NASA Astrophysics Data System (ADS)

    Kyzio?, Karol; Kluska, Stanis?awa; Janu?, Marta; ?roda, Marcin; Jastrz?bski, Witold; Kaczmarek, ?ukasz

    2014-08-01

    The paper reports results of the study of surface composition and selected functional properties of 7075 (Al-Zn) alloys modified in Ar, N2, SiH4 and CH4 atmosphere at reduced pressure. RF CVD (Radio Frequency Chemical Vapour Deposition) technique was used in the study. The type or weight percentage of carbon in each modification varied in the resultant SiN:H and SiCN:H coatings. Alloy samples were treated with Ar+ plasma etching and N+ ion implantation at reduced pressure. The tests proved the values of selected mechanical properties (hardness ca. 10.5 GPa, Young modulus ca. 95 GPa) and adhesion (delamination force ca. 11.5 mN) to be higher in the case of SiCN:H anti-wear coating (deposited in SiH4:CH4:N2 = 1:1:2 gas mixture) than the values of the respective parameters obtained in the remaining modifications. Further, carbon doped coatings (SiCN:H) exhibited significantly improved hardness (by about 50 to 70%) and nearly threefold increase in delamination force in comparison with SiCN:H coatings.

  14. Control of carbon content in amorphous GeTe films deposited by plasma enhanced chemical vapor deposition (PE-MOCVD) for phase-change random access memory applications

    NASA Astrophysics Data System (ADS)

    Aoukar, M.; Szkutnik, P. D.; Jourde, D.; Pelissier, B.; Michallon, P.; No, P.; Valle, C.

    2015-07-01

    Amorphous and smooth GeTe thin films are deposited on 200?mm silicon substrates by plasma enhancedmetal organic chemical vapor deposition (PE-MOCVD) using the commercial organometallic precursors TDMAGe and DIPTe as Ge and Te precursors, respectively. X-ray photoelectron spectroscopy (XPS) measurements show a stoichiometric composition of the deposited GeTe films but with high carbon contamination. Using information collected by Optical Emission Spectroscopy (OES) and XPS, the origin of carbon contamination is determined and the dissociation mechanisms of Ge and Te precursors in H2 + Ar plasma are proposed. As a result, carbon level is properly controlled by varying operating parameters such as plasma radio frequency power, pressure and H2 rate. Finally, GeTe films with carbon level as low as 5?at. % are obtained.

  15. Ferromanganese nodules from MANOP Sites H, S, and R-Control of mineralogical and chemical composition by multiple accretionary processes

    USGS Publications Warehouse

    Dymond, J.; Lyle, M.; Finney, B.; Piper, D.Z.; Murphy, K.; Conard, R.; Pisias, N.

    1984-01-01

    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.

  16. Microstructure and Mechanical Properties of Ti-TiB Based Short-Fiber Composite Materials Manufactured by Casting and Subjected to Deformation Processing

    NASA Astrophysics Data System (ADS)

    Gaisin, R. A.; Imayev, V. M.; Imayev, R. M.; Gaisina, É. R.

    2015-10-01

    The microstructure and mechanical properties of Ti-TiB based short-fiber composite materials manufactured by casting and subjected to deformation processing are investigated. Commercially pure VT1-0 titanium and two-phase VT8 alloys are used for matrix alloys. It is established that the short-fiber composite materials comprising about 10 vol.% of titanium monoboride can be successfully prepared by conventional casting. Regimes of deformation processing of the composite materials providing reorientation of titanium monoboride fibers with retention of a high length-to-diameter ratio are developed. The composite materials after deformation processing demonstrate higher strength characteristics and, as demonstrated for the VT8 based composite, high-temperature strength compared to the matrix material without a radical reduction of ductility.

  17. Studies on the morphological traits and chemical composition of the fruit of six tomato cultivars recommended as raw material for freezing.

    PubMed

    Kmiecik, W; Lisiewska, Z

    2000-10-01

    Evaluation was made of six tomato cultivars (Micra RS, Dual Plus F1, Pasadena F1, RS 356743 F1, RS 933409 F1, and Sanga F1) produced by Seminis Vegetable Seeds breeders and recommended for freezing in slices or cubes. Of the investigated cultivars only RS 356743 F1 showed morphological traits that did not recommend it for this processing technology. The ratio sugars/acids, the content of protopectins and pectins, and the activity of enzymes does not recommend RS 356743 F1 and Pasadena F1. No significant differences in the content of soluble solids, alkalinity of ash, carotenoids, lycopene, chlorophylls, and peroxidase activity between the cultivars were determined. Differences in the value of the remaining indices were small, not exceeding 10% in the content of dry matter and in active acidity, 20% in the content of sugars, ash, vitamin C, and in the activity of lipase, and 30% in the content of dietary fibre, total nitrogen, total acids, and beta-carotene. The only differences higher than 30% concerned the content of protopectins, pectins, nitrates, and catalase activity. PMID:11075378

  18. Chemical evolution of Macondo crude oil during laboratory degradation as characterized by fluorescence EEMs and hydrocarbon composition.

    PubMed

    Zhou, Zhengzhen; Liu, Zhanfei; Guo, Laodong

    2013-01-15

    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

  19. Chemical composition and temperature dependent performance of ZnO-thin film transistors deposited by pulsed and continuous spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Ortel, Marlis; Balster, Torsten; Wagner, Veit

    2013-12-01

    Zinc oxide thin film transistors (TFTs) deposited by continuous and pulsed spray pyrolysis were investigated to analyze process kinetics which make reduction of process temperature possible. Thus, fluid mechanics, chemical composition, electrical performance, and deposition and annealing temperature were systematically analyzed. It was found that ZnO layers continuously deposited at 360 °C contained zinc oxynitrides, CO3, and hydro carbonate groups from pyrolysis of basic zinc acetate. Statistically, every second wurtzite ZnO unit cell contained an impurity atom. The purity and performance of the ZnO-TFTs increased systematically with increasing deposition temperature due to an improved oxidation processes. At 500 °C the zinc to oxygen ratio exceeded a high value of 0.96. Additionally, the ZnO film was not found to be in a stabilized state after deposition even at high temperatures. Introducing additional subsequent annealing steps stabilizes the film and allows the reduction of the overall thermal stress to the substrate. Further improvement of device characteristics was obtained by pulsed deposition which allowed a more effective transport of the by-products and oxygen. A significant reduction of the deposition temperature by 140 °C was achieved compared to the same performance as in continuous deposition mode. The trap density close to the Fermi energy could be reduced by a factor of two to 4 × 1017 eV-1 cm-3 due to the optimized combustion process on the surface. The optimization of the deposition processes made the fabrication of TFTs with excellent performance possible. The mobility was high and exceeded 12 cm2/V s, the subthreshold slope was 0.3 V dec-1, and an on-set close to the ideal value of 0 V was achieved.

  20. Chemical composition and temperature dependent performance of ZnO-thin film transistors deposited by pulsed and continuous spray pyrolysis

    SciTech Connect

    Ortel, Marlis; Balster, Torsten; Wagner, Veit

    2013-12-21

    Zinc oxide thin film transistors (TFTs) deposited by continuous and pulsed spray pyrolysis were investigated to analyze process kinetics which make reduction of process temperature possible. Thus, fluid mechanics, chemical composition, electrical performance, and deposition and annealing temperature were systematically analyzed. It was found that ZnO layers continuously deposited at 360?C contained zinc oxynitrides, CO{sub 3}, and hydro carbonate groups from pyrolysis of basic zinc acetate. Statistically, every second wurtzite ZnO unit cell contained an impurity atom. The purity and performance of the ZnO-TFTs increased systematically with increasing deposition temperature due to an improved oxidation processes. At 500?C the zinc to oxygen ratio exceeded a high value of 0.96. Additionally, the ZnO film was not found to be in a stabilized state after deposition even at high temperatures. Introducing additional subsequent annealing steps stabilizes the film and allows the reduction of the overall thermal stress to the substrate. Further improvement of device characteristics was obtained by pulsed deposition which allowed a more effective transport of the by-products and oxygen. A significant reduction of the deposition temperature by 140?C was achieved compared to the same performance as in continuous deposition mode. The trap density close to the Fermi energy could be reduced by a factor of two to 4??10{sup 17}?eV{sup ?1}?cm{sup ?3} due to the optimized combustion process on the surface. The optimization of the deposition processes made the fabrication of TFTs with excellent performance possible. The mobility was high and exceeded 12 cm{sup 2}/V s, the subthreshold slope was 0.3 V dec{sup ?1}, and an on-set close to the ideal value of 0?V was achieved.

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

    SciTech Connect

    Mandell, J.F.; Samborsky, D.D.

    1997-12-01

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

  2. Hyphenation of Thermal Analysis to Ultrahigh-Resolution Mass Spectrometry (Fourier Transform Ion Cyclotron Resonance Mass Spectrometry) Using Atmospheric Pressure Chemical Ionization For Studying Composition and Thermal Degradation of Complex Materials.

    PubMed

    Rüger, Christopher P; Miersch, Toni; Schwemer, Theo; Sklorz, Martin; Zimmermann, Ralf

    2015-07-01

    In this study, the hyphenation of a thermobalance to an ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometer (UHR FTICR MS) is presented. Atmospheric pressure chemical ionization (APCI) is used for efficient ionization. The evolved gas analysis (EGA), using high-resolution mass spectrometry allows the time-resolved molecular characterization of thermally induced processes in complex materials or mixtures, such as biomass or crude oil. The most crucial part of the setup is the hyphenation between the thermobalance and the APCI source. Evolved gases are forced to enter the atmospheric pressure ionization interface of the MS by applying a slight overpressure at the thermobalance side of the hyphenation. Using the FTICR exact mass data, detailed chemical information is gained by calculation of elemental compositions from the organic species, enabling a time and temperature resolved, highly selective detection of the evolved species. An additional selectivity is gained by the APCI ionization, which is particularly sensitive toward polar compounds. This selectivity on the one hand misses bulk components of petroleum samples such as alkanes and does not deliver a comprehensive view but on the other hand focuses particularly on typical evolved components from biomass samples. As proof of principle, the thermal behavior of different fossil fuels: heavy fuel oil, light fuel oil, and a crude oil, and different lignocellulosic biomass, namely, beech, birch, spruce, ash, oak, and pine as well as commercial available softwood and birch-bark pellets were investigated. The results clearly show the capability to distinguish between certain wood types through their molecular patterns and compound classes. Additionally, typical literature known pyrolysis biomass marker were confirmed by their elemental composition, such as coniferyl aldehyde (C10H10O3), sinapyl aldehyde (C11H12O4), retene (C18H18), and abietic acid (C20H30O2). PMID:26024433

  3. 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

    Happo, M.S.; Hirvonen, M.R.; Halinen, A.I.; Jalava, P.I.; Pennanen, A.S.; Sillanpaa, M.; Hillamo, R.; Salonen, R.O.

    2008-07-01

    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.

  4. Chemical compositions responsible for inflammation and tissue damage in the mouse lung by coarse and fine particulate samples from contrasting air pollution in Europe.

    PubMed

    Happo, Mikko S; Hirvonen, Maija-Riitta; Halinen, Arja I; Jalava, Pasi I; Pennanen, Arto S; Sillanpaa, Markus; Hillamo, Risto; Salonen, Raimo O

    2008-11-01

    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 (PM(2.5-0.2)) and coarse (PM(10-2.5)) 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 PM(2.5-0.2) correlated positively and some secondary inorganic ions (NO3(-), NH4(+)) negatively with the inflammatory activity. Total organic matter and SO4(2-) had no consistent correlations. In addition, the soil-derived constituents (Ca2+, Al, Fe, Si) showed positive correlations with the PM(2.5-0.2)-induced inflammatory activity, but their role in PM(10-2.5) 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 PM(2.5-0.2) 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. PMID:18855153

  5. Physical Characterization and Steam Chemical Reactivity of Carbon Fiber Composites

    SciTech Connect

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

    2001-05-01

    This report documents experiments and analyses that have been done at the Idaho National Engineering and Environmental Laboratory (INEEL) to measure the steam chemical reactivity of two types of carbon fiber composites, NS31 and NB31, proposed for use at the divertor strike points in an ITER-like tokamak. These materials are 3D CFCs constituted by a NOVOLTEX preform and densified by pyrocarbon infiltration and heat treatment. NS31 differs from NB31 in that the final infiltration was done with liquid silicon to reduce the porosity and enhance the thermal conductivity of the CFC. Our approach in this work was twofold: (1) physical characterization measurements of the specimens and (2) measurements of the chemical reactivity of specimens exposed to steam.

  6. Composite Materials for Wind Power Turbine Blades

    NASA Astrophysics Data System (ADS)

    Brndsted, Povl; Lilholt, Hans; Lystrup, Aage

    2005-08-01

    Renewable energy resources, of which wind energy is prominent, are part of the solution to the global energy problem. Wind turbine and the rotorblade concepts are reviewed, and loadings by wind and gravity as important factors for the fatigue performance of the materials are considered. Wood and composites are discussed as candidates for rotorblades. The fibers and matrices for composites are described, and their high stiffness, low density, and good fatigue performance are emphasized. Manufacturing technologies for composites are presented and evaluated with respect to advantages, problems, and industrial potential. The important technologies of today are prepreg (pre-impregnated) technology and resin infusion technology. The mechanical properties of fiber composite materials are discussed, with a focus on fatigue performance. Damage and materials degradation during fatigue are described. Testing procedures for documentation of properties are reviewed, and fatigue loading histories are discussed, together with methods for data handling and statistical analysis of (large) amounts of test data. Future challenges for materials in the field of wind turbines are presented, with a focus on thermoplastic composites, new structural materials concepts, new structural design aspects, structural health monitoring, and the coming trends and markets for wind energy.

  7. Investigation of the chemical compositions in tobacco of different origins and maturities at harvest by GC-MS and HPLC-PDA-QTOF-MS.

    PubMed

    Xia, Bing; Feng, Mengmeng; Xu, Gang; Xu, Jindi; Li, Songlin; Chen, Xiaozhen; Ding, Lisheng; Zhou, Yan

    2014-06-01

    Tobacco samples of a same cultivar grown in different plantations in China were evaluated for their chemical compositions at different maturities for the first time. This was accomplished by a comprehensive and reliable method using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-photodiode array-quadrupole time-of-flight mass spectrometry (HPLC-PDA-QTOF-MS) to analyze the fat-soluble and polar components in 12 batches of tobacco samples of three origins and four maturities. The GC-MS analyses showed that tobacco samples harvested at 40 days after transplantation exhibited more fat-soluble components, while those harvested at 100 days after transplantation exhibited the least fat-soluble components. Tentatively, identification of the main components as well as quantitative analyses of eight reference compounds, including five alkaloids, two polyphenols, and a coumarin, was performed by the developed HPLC-QTOF-PDA method. Results showed significant differences among origins and maturities in the contents of these compounds. The nicotine contents showed great variety among the 12 tobacco samples. The highest nicotine content were found in a sample from Zhengzhou harvested at 40 days after transplantation (ZZ-T with 25399.39 308.95 ?g/g), and the lowest nicotine level was detected in a sample from Zunyi harvested at 60 days after transplantation (ZY-X with 1654.49 34.52 ?g/g). The highest level of rutin was found in a Jiangchuan sample harvested at 60 days after transplantation (JC-X with 725.93 40.70 ?g/g), and the lowest rutin content was detected in a Zunyi tobacco sample harvested at 60 days after transplantation (ZY-X with 87.42 2.78 ?g/g). The developed method provided a convenient approach which might be applied for rapid maturity evaluation and tobacco flavor identification and also holds the potential for analysis of compounds present in other plants. PMID:24833170

  8. Ceramic Aerogel Composite Materials and Characterization

    NASA Technical Reports Server (NTRS)

    White, Susan; Hrubesh, Lawrence W.; Rasky, Daniel J. (Technical Monitor)

    1997-01-01

    Aerogels a.k.a "Solid Smoke" are gels with the liquid phase replaced by gas, leaving behind a highly porous material with a nanoscale framework. Due to the porous, nanoscale structure, aerogels have the lowest known density and conductivity of solids. Aerogels have the potential for being a breakthrough material because of their extremely light weight and unique properties. In this paper, we address overcoming their most profound weaknesses: mechanical fragility and very high surface activity, which leads to a lowered sintering temperature. A matrix of ceramic aerogel composite materials was produced to investigate their properties and functionality. Mechanical property measurements and Scanning Electron Micrographs are used to identify trends and structure of these ceramic composite materials. Thermal cycling was used to identify the sintering points of the materials.

  9. Composite materials for fusion applications

    SciTech Connect

    Jones, R.H.; Henager, C.H. Jr.; Hollenberg, G.W.

    1991-10-01

    Ceramic matrix composites, CMCs, are being considered for advanced first-wall and blanket structural applications because of their high-temperature properties, low neutron activation, low density and low coefficient of expansion coupled with good thermal conductivity and corrosion behavior. This paper presents a review and analysis of the hermetic, thermal conductivity, corrosion, crack growth and radiation damage properties of CMCs. It was concluded that the leak rates of a gaseous coolant into the plasma chamber or tritium out of the blanket could exceed design criteria if matrix microcracking causes existing porosity to become interconnected. Thermal conductivities of unirradiated SiC/SiC and C/SiC materials are about 1/2 to 2/3 that of Type 316 SS whereas the thermal conductivity for C/C composites is seven times larger. The thermal stress figure-of-merit value for CMCs exceeds that of Type 316 SS for a single thermal cycle. SiC/SiC composites are very resistant to corrosion and are expected to be compatible with He or Li coolants if the O{sub 2} concentrations are maintained at the appropriate levels. CMCs exhibit subcritical crack growth at elevated temperatures and the crack velocity is a function of the corrosion conditions. The radiation stability of CMCs will depend on the stability of the fiber, microcracking of the matrix, and the effects of gaseous transmutation products on properties. 23 refs., 14 figs., 1 tab.

  10. 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

    Zelibor, J. L.; Romankiw, L.; Hatcher, P. G.; Colwell, R. R.

    1988-01-01

    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. PMID:16347601

  11. Chemical composition of distillers grains, a review.

    PubMed

    Liu, KeShun

    2011-03-01

    In recent years, increasing demand for ethanol as a fuel additive and decreasing dependency on fossil fuels have resulted in a dramatic increase in the amount of grains used for ethanol production. Dry-grind is the major process, resulting in distillers dried grains with solubles (DDGS) as a major coproduct. Like fuel ethanol, DDGS has quickly become a global commodity. However, high compositional variation has been the main problem hindering its use as a feed ingredient. This review provides updated information on the chemical composition of distillers grains in terms of nutrient levels, changes during dry-grind processing, and causes for large variation. The occurrence in grain feedstock and the fate of mycotoxins during processing are also covered. During processing, starch is converted to glucose and then to ethanol and carbon dioxide. Most other components are relatively unchanged but concentrated in DDGS about 3-fold over the original feedstock. Mycotoxins, if present in the original feedstock, are also concentrated. Higher fold of increases in S, Na, and Ca are mostly due to exogenous addition during processing, whereas unusual changes in inorganic phosphorus (P) and phytate P indicate phytate hydrolysis by yeast phytase. Fermentation causes major changes, but other processing steps are also responsible. The causes for varying DDGS composition are multiple, including differences in feedstock species and composition, process methods and parameters, the amount of condensed solubles added to distiller wet grains, the effect of fermentation yeast, and analytical methodology. Most of them can be attributed to the complexity of the dry-grind process itself. It is hoped that information provided in this review will improve the understanding of the dry-grind process and aid in the development of strategies to control the compositional variation in DDGS. PMID:21299215

  12. Changes in chemical and isotopic signatures of plant materials during degradation: Implication for assessing various organic inputs in estuarine systems

    NASA Astrophysics Data System (ADS)

    Dai, Jihong; Sun, Ming-Yi; Culp, Randolph A.; Noakes, John E.

    2005-07-01

    To evaluate applicability of the end-member mixing model in assessment of input and transport of organic carbon in estuarine systems, we incubated marine diatom, land grass, and salt marsh plant in Altamaha estuarine water for two months. Chemical and isotopic parameters (bulk organic carbon/nitrogen contents, lipid compositions, stable C/N isotopes, and lipid stable carbon isotopic ratios) were analyzed for fresh and degraded materials. The results showed that although the C/N and δ15N ratios of three materials varied similarly during degradation, the bulk δ13C, lipid compositions, and lipid stable carbon isotopic compositions varied differently from material to material and from compound to compound, implying that applications of the end-member model should consider the diagenetic status of organic materials and the potential changes in chemical and isotopic signatures.

  13. Chemical composition and morphology of welding fume particles and grinding dusts

    SciTech Connect

    Karlsen, J.T.; Farrants, G.; Torgrimsen, T.; Reith, A. )

    1992-05-01

    Elemental composition and morphology of pure manual metal arc (MMA) welding fumes, pure grinding dust, and combined fume/dust air samples were collected and determined separately under semilaboratory conditions. The base material was stainless steel. The purpose of the present study was to create a synthetic' work situation under semilaboratory conditions by combining one grinding period and two MMA welding periods and comparing these results with results during welding in a workshop. The duty cycles of pure welding and of pure grinding were also observed. A comparison was also made between metal inert gas (MIG) and MMA welding on stainless steel as well as a nickel-rich alloy under regular conditions. The amount of collected material was determined by weighing the membrane filters before and after exposure, and the element contents were determined by atomic spectroscopy. Other transmission electron microscopy (TEM) filters were used for TEM and computer-image analysis, in which the amount of collected material and its morphological characteristics were observed. The arcing time and the consumption of filler material were estimated for different kinds of electrodes. Chemical analysis showed that the contents of manganese and total chromium were lower in grinding dust than in welding fumes. The contents of hexavalent chromium, Cr(VI), in grinding dust were undetectable. Samples collected in welding shops where concomitant grinding was performed contained about 30% less Cr(VI) than those collected under laboratory conditions during welding only. The sizes and shapes of the particles depend on the welding process and distance of collection from the plume of the fume. To compare laboratory experiments with regular welding situations, the experiment must resemble industrial welding.

  14. Chemical composition and morphology of welding fume particles and grinding dusts.

    PubMed

    Karlsen, J T; Farrants, G; Torgrimsen, T; Reith, A

    1992-05-01

    Elemental composition and morphology of pure manual metal arc (MMA) welding fumes, pure grinding dust, and combined fume/dust air samples were collected and determined separately under semilaboratory conditions. The base material was stainless steel. The purpose of the present study was to create a "synthetic" work situation under semilaboratory conditions by combining one grinding period and two MMA welding periods and comparing these results with results during welding in a workshop. The duty cycles of pure welding and of pure grinding were also observed. A comparison was also made between metal inert gas (MIG) and MMA welding on stainless steel as well as a nickel-rich alloy under regular conditions. The amount of collected material was determined by weighing the membrane filters before and after exposure, and the element contents were determined by atomic spectroscopy. Other transmission electron microscopy (TEM) filters were used for TEM and computer-image analysis, in which the amount of collected material and its morphological characteristics were observed. The arcing time and the consumption of filler material were estimated for different kinds of electrodes. Chemical analysis showed that the contents of manganese and total chromium were lower in grinding dust than in welding fumes. The contents of hexavalent chromium, Cr(VI), in grinding dust were undetectable. Samples collected in welding shops where concomitant grinding was performed contained about 30% less Cr(VI) than those collected under laboratory conditions during welding only. The sizes and shapes of the particles depend on the welding process and distance of collection from the plume of the fume. To compare laboratory experiments with regular welding situations, the experiment must resemble industrial welding.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1609739

  15. Profiling the Triacylglyceride Contents in Bat Integumentary Lipids by Preparative Thin Layer Chromatography and MALDI-TOF Mass Spectrometry

    PubMed Central

    Pannkuk, Evan L.; Risch, Thomas S.; Savary, Brett J.

    2013-01-01

    The mammalian integument includes sebaceous glands that secrete an oily material onto the skin surface. Sebum production is part of the innate immune system that is protective against pathogenic microbes. Abnormal sebum production and chemical composition are also a clinical symptom of specific skin diseases. Sebum contains a complex mixture of lipids, including triacylglycerides, which is species-specific. The broad chemical properties exhibited by diverse lipid classes hinder the specific determination of sebum composition. Analytical techniques for lipids typically require chemical derivatizations that are labor-intensive and increase sample preparation costs. This paper describes how to extract lipids from mammalian integument, separate broad lipid classes by thin-layer chromatography, and profile the triacylglyceride contents using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This robust method enables a direct determination of the triacylglyceride profiles among species and individuals, and it can be readily applied to any taxonomic group of mammals. PMID:24056580

  16. Global Materials Structure Search with Chemically Motivated Coordinates.

    PubMed

    Panosetti, Chiara; Krautgasser, Konstantin; Palagin, Dennis; Reuter, Karsten; Maurer, Reinhard J

    2015-12-01

    Identification of relevant reaction pathways in ever more complex composite materials and nanostructures poses a central challenge to computational materials discovery. Efficient global structure search, tailored to identify chemically relevant intermediates, could provide the necessary first-principles atomistic insight to enable a rational process design. In this work we modify a common feature of global geometry optimization schemes by employing automatically generated collective curvilinear coordinates. The similarity of these coordinates to molecular vibrations enhances the generation of chemically meaningful trial structures for covalently bound systems. In the application to hydrogenated Si clusters, we concomitantly observe a significantly increased efficiency in identifying low-energy structures and exploit it for an extensive sampling of potential products of silicon-cluster soft landing on Si(001) surfaces. PMID:26444084

  17. Yield and chemical composition of fractions from fermented shrimp biowaste.

    PubMed

    Narayan, Bhaskar; Velappan, Suresh Puthanveetil; Zituji, Sakhare Patiram; Manjabhatta, Sachindra Nakkerike; Gowda, Lalitha Ramakrishna

    2010-01-01

    Chemical composition of chitinous residue and fermentation liquor fractions, obtained from fermented shrimp biowaste, was evaluated in order to explore their potential for further utilization. Lyophilization of the liquor fraction obtained after fermentation resulted in a powder rich in both protein (30%) and carotenoids (217.18 +/- 2.89 microg/g). The yield of chitinous residue was 44% (w/w) whereas the yield of lyophilized powder was >25% (w/v). About 69% of total carotenoids were recovered by fermentation. Fermentation resulted in the removal of both protein as well as ash content from the shrimp biowaste, as indicated by approximately 92% deproteination and >76% demineralization, respectively. Post fermentation, the residue had a chitin content of >90%. The lyophilized liquor fraction had all the essential amino acids (except threonine) in quantities comparable to Food & Agriculture Organization/World Health Organization reference protein. The composition of fermentation liquor is indicative of its potential for application as an amino acid supplement in aquaculture feed formulations. PMID:19723823