Composite Transport Model and Water and Solute Transport across Plant Roots: An Update.

Science.gov (United States)

Kim, Yangmin X; Ranathunge, Kosala; Lee, Seulbi; Lee, Yejin; Lee, Deogbae; Sung, Jwakyung

2018-01-01

The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM). It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots - apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs), which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic). Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle). The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

Separation of radio cesium from PUREX feed solution by sorption on composite ammonium molybdo phosphate (AMP)

International Nuclear Information System (INIS)

Singh, I.J.; Achuthan, P.V.; Jain, S.; Janardanan, C.; Gopalakrishnan, V.; Wattal, P.K.; Ramanujam, A.

2001-01-01

Composite AMP exchanger was developed and evaluated for separation of radio cesium from dissolver solutions of PUREX process using a column experiment. The composite shows excellent sorption of radio cesium from dissolver solutions without any loss of plutonium and uranium. The removal of radio cesium from dissolver solutions will help in lowering the degradation of tri-n-butyl phosphate (TBP) in the solvent extraction process and will also help in reducing the radiation related problems. (author)

Corrosion behavior of magnesium-graphene composites in sodium chloride solutions

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Muhammad Rashad

2017-09-01

Full Text Available Coating of graphene and graphene/polymer composites on metals improves the corrosion resistance of metal substrates. On other hand, graphene embedded inside metal (especially Mg matrices increases or decreases corrosion, is a crucial factor and must be explored. In present study, electrochemical behaviors of magnesium alloys (AZ31 and AZ61 and their composites reinforced with graphene nanoplatelets (GNPs were carried out in 3.5% NaCl solution by polarization method. The surface morphology of composites before and after corrosion tests were analyzed using scanning electron microscopy. Experimental results revealed that presence of graphene nanoplatelets in different matrices decrease corrosion resistance of composites. This may be attributed to presence of graphene nanoplatelets which activates the corrosion of magnesium/alloys due to the occurrence of galvanic corrosion and this effect increases with increasing graphene nanoplatelets content. Further, an appropriate model describing the corrosion mechanism was proposed.

Scale-dependent effects on wave propagation in magnetically affected single/double-layered compositionally graded nanosize beams

Science.gov (United States)

Ebrahimi, Farzad; Barati, Mohammad Reza

2018-04-01

This article deals with the wave propagation analysis of single/double layered functionally graded (FG) size-dependent nanobeams in elastic medium and subjected to a longitudinal magnetic field employing nonlocal elasticity theory. Material properties of nanobeam change gradually according to the sigmoid function. Applying an analytical solution, the acoustical and optical dispersion relations are explored for various wave number, nonlocality parameter, material composition, elastic foundation constants, and magnetic field intensity. It is found that frequency and phase velocity of waves propagating in S-FGM nanobeam are significantly affected by these parameters. Also, presence of cut-off and escape frequencies in wave propagation analysis of embedded S-FGM nanobeams is investigated.

Metastable Equilibrium Solubility Distribution of Carbonated Apatite as a Function of Solution Composition.

Science.gov (United States)

Chhettry; Wang; Hsu; Fox; Baig; Barry; Zhuang; Otsuka; Higuchi

1999-10-01

Previous studies have shown that carbonated apatites (CAPs) exhibit the phenomenon of metastable equilibrium solubility (MES) in weak acid media. The purpose of the present investigation was to examine two questions: first, whether the MES concept is applicable to a broader range of solution conditions and, second, whether a driving force function associated with a surface complex having a constant stoichiometry governs the dissolution of CAP and, if so, what is this stoichiometry. CAP preparations with carbonate contents of 1.8-5.7 wt% (synthesized by hydrolysis of dicalcium phosphate anhydrate in solutions of varying bicarbonate levels or by direct precipitation from supersaturated calcium/phosphate/carbonate solutions) were studied as follows. MES distributions for each of the CAP preparations were determined by equilibrating the CAP under stirred conditions in a series of acetate buffers (0.10 M) containing various levels of calcium and phosphate in the pH range 4.5-6.5 and a solution calcium/phosphate ratio in the range 0.1-10. The amount dissolved in each instance was regarded as the fraction of the CAP possessing an MES value greater than that corresponding to the ion activity product (IAP) of the equilibrating solution. The solution IAPs were calculated from the solution compositions using plausible calcium phosphate stoichiometries, viz., dicalcium phosphate dihydrate, octacalcium phosphate, tricalcium phosphate, hydroxyapatite, carbonated apatite (based on the bulk composition of the particular CAP involved in the experiment), and tetracalcium phosphate. The fraction of CAP dissolved was plotted against the solution IAPs for each experimental set using each of the six assumed stoichiometries for the surface complex. The results demonstrated that the MES concept was applicable to all of the CAP preparations in media of various solution compositions and different pH levels. The most important new outcome of this study was that MES profiles for each of the

Effect of a New Surface Treatment Solution on the Bond Strength of Composite to Enamel

Science.gov (United States)

2016-06-01

Bond Strength of Composite to Enamel " is appropriately acknowledged and, beyond brief excerpts, is with the permission of the copyright owner...Solution on the Bond Strength of Composite to Enamel ABSTRACT Clean & Boost (Apex Dental Materials) is a novel surface treatment solution...designed to be used in place of phosphoric acid to increase the bond strength of self-etch adhesives to enamel and more effectively remove contaminants

Importance of waste composition for Life Cycle Assessment of waste management solutions

DEFF Research Database (Denmark)

Bisinella, Valentina; Götze, Ramona; Conradsen, Knut

2017-01-01

The composition of waste materials has fundamental influence on environmental emissions associated with waste treatment, recycling and disposal, and may play an important role also for the Life Cycle Assessment (LCA) of waste management solutions. However, very few assessments include effects...... of the waste composition and waste LCAs often rely on poorly justified data from secondary sources. This study systematically quantifiesy the influence and uncertainty on LCA results associated with selection of waste composition data. Three archetypal waste management scenarios were modelled with the waste...... LCA model EASETECH based on detailed waste composition data from the literature. The influence from waste composition data on the LCA results was quantified with a step-wise Global Sensitivity Analysis (GSA) approach involving contribution, sensitivity, uncertainty and discernibility analyses...

Effect of the cationic composition of sorption solution on the quantification of sorption-desorption parameters of heavy metals in soils

International Nuclear Information System (INIS)

Sastre, J.; Rauret, G.; Vidal, M.

2006-01-01

We obtained the sorption isotherms of Cd, Cu, Pb and Zn in clay, clay saline and organic soils. The distribution coefficients (K d ) were determined in 0.02 eq l -1 CaCl 2 and in a solution that simulated the soil solution cationic composition. The K d values greatly varied with the composition of the sorption solution and the initial metal concentration. The sorption experiments were complemented with the quantification of the extractable metal, to estimate the reversibility of metal sorption. The extraction yields depended on the metal-soil combination, and the initial metal concentration, showing no correlation with previous K d values. The effect of the solution composition in mobility predictions was estimated through a Retention Factor, defined as the ratio of the K d versus the extraction yield. Results showed that risk was over- or underestimated using the CaCl 2 medium in soils with a markedly different soil solution composition. - Sorption solution composition modifies metal sorption-desorption pattern in soils

Composite Transport Model and Water and Solute Transport across Plant Roots: An Update

Directory of Open Access Journals (Sweden)

Yangmin X. Kim

2018-02-01

Full Text Available The present review examines recent experimental findings in root transport phenomena in terms of the composite transport model (CTM. It has been a well-accepted conceptual model to explain the complex water and solute flows across the root that has been related to the composite anatomical structure. There are three parallel pathways involved in the transport of water and solutes in roots – apoplast, symplast, and transcellular paths. The role of aquaporins (AQPs, which facilitate water flows through the transcellular path, and root apoplast is examined in terms of the CTM. The contribution of the plasma membrane bound AQPs for the overall water transport in the whole plant level was varying depending on the plant species, age of roots with varying developmental stages of apoplastic barriers, and driving forces (hydrostatic vs. osmotic. Many studies have demonstrated that the apoplastic barriers, such as Casparian bands in the primary anticlinal walls and suberin lamellae in the secondary cell walls, in the endo- and exodermis are not perfect barriers and unable to completely block the transport of water and some solute transport into the stele. Recent research on water and solute transport of roots with and without exodermis triggered the importance of the extension of conventional CTM adding resistances that arrange in series (epidermis, exodermis, mid-cortex, endodermis, and pericycle. The extension of the model may answer current questions about the applicability of CTM for composite water and solute transport of roots that contain complex anatomical structures with heterogeneous cell layers.

Magnesium Affects Poly(3-hydroxybutyrate-co-4-hydroxybutyrate Content and Composition by Affecting Glucose Uptake in Delftia acidovorans

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Lee, W. H.

2007-01-01

Full Text Available Precise control of polyhydroxyalkanoate (PHA composition is necessary in order to synthesize polymers with specific properties. Among the various types of PHA that have been identified, those that contain 4-hydroxybutyrate (4HB monomers are especially useful in the medical and pharmaceutical fields as absorbable biomaterial. In this study, we have investigated the effect of magnesium concentration on the biosynthesis of poly(3-hydroxybutyrate-co-4-hydroxybutyrate [P(3HB-co-4HB] by Delftia acidovorans DS-17. Our results show that, magnesium affects the copolymer content and composition by affecting glucose uptake from the culture medium. Higher concentrations of magnesium resulted in lower molar fractions of 3HB in the copolymer and reduced uptake of glucose. The results show for the first time that magnesium may be used to achieve fine control of biologically synthesized PHA copolymer composition.

Functional porous composites by blending with solution-processable molecular pores.

Science.gov (United States)

Jiang, S; Chen, L; Briggs, M E; Hasell, T; Cooper, A I

2016-05-25

We present a simple method for rendering non-porous materials porous by solution co-processing with organic cage molecules. This method can be used both for small functional molecules and for polymers, thus creating porous composites by molecular blending, rather than the more traditional approach of supporting functional molecules on pre-frabricated porous supports.

Synthesis of a magnetic composite resin and its cobalt removal characteristics in aqueous solution

International Nuclear Information System (INIS)

Kim, Young Kyun; Lee, Kun Jai

2001-01-01

A series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenolsulphonic-formaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. The ion exchange and sorption characteristics of the composite resin prepared by the above method at various conditions were experimentally disclosed. The composite resin prepared shows stably high removal efficiency to Co(II) species in aqueous solution in a wide range of solution pH. The overall isotherm is qualitatively explained by the generalized adsorption isotherm concept proposed by McKinley. The standard enthalpy change derived from van't Hoff equation conforms to the typical range for chemisorption or ion exchange. The selectivity of the PSF-F (phenolsulphonic formaldehyde-iron ferrite) composite resin to Co(II) species and other competing chemicals (i.e. Na 2 EDTA, Ca(II) and Na) was compared. It is anticipated that the composite resin can also be used for column-operation with process-control by applying external magnetic field, since the rigid bead-type composite resin shows magnetic-susceptibility due to its paramagnetic inorganic constituent (i.e. iron ferrite). (author)

The combined effect of food-simulating solutions, brushing and staining on color stability of composite resins

Science.gov (United States)

Silva, Tânia Mara Da; Sales, Ana Luísa Leme Simões; Pucci, Cesar Rogerio; Borges, Alessandra Bühler; Torres, Carlos Rocha Gomes

2017-01-01

Abstract Objective: This study evaluated the effect of food-simulating media associated with brushing and coffee staining on color stability of different composite resins. Materials and methods: Eighty specimens were prepared for each composite: Grandio SO (Voco), Amaris (Voco), Filtek Z350XT (3M/ESPE), Filtek P90 (3M/ESPE). They were divided into four groups according to food-simulating media for 7 days: artificial saliva (control), heptane, citric acid and ethanol. The composite surface was submitted to 10,950 brushing cycles (200 g load) in an automatic toothbrushing machine. The specimens were darkened with coffee solution at 37 °C for 24 h. After each treatment, color measurements were assessed by spectrophotometry, using CIE L*a*b* system. The overall color change (ΔE) was determined for each specimen at baseline (C1) and after the treatments (food-simulating media immersion/C2, brushing/C3 and dye solution/C4). Data were analyzed by two-way repeated measures ANOVA and Tukey’s tests (p composites (p = .001), time (p = .001) and chemical degradation (p = .002). The mean of ΔE for composites were: Z350XT (5.39)a, Amaris (3.89)b, Grandio (3.75)bc, P90 (3.36)c. According to food-simulating media: heptane (4.41)a, citric acid (4.24)a, ethanol (4.02)ab, artificial saliva (3.76)b. For the treatments: dye solution (4.53)a, brushing (4.26)a, after food-simulating media (3.52)b. Conclusions: The composite resin Filtek Z350XT showed significantly higher staining than all other composite resin tested. The immersion in heptane and citric acid produced the highest color alteration than other food-simulating media. The exposure of samples to brushing protocols and darkening in coffee solution resulted in significant color alteration of the composite resins. PMID:28642926

High Dielectric Performance of Solution-Processed Aluminum Oxide-Boron Nitride Composite Films

Science.gov (United States)

Yu, Byoung-Soo; Ha, Tae-Jun

2018-04-01

The material compositions of oxide films have been extensively investigated in an effort to improve the electrical characteristics of dielectrics which have been utilized in various electronic devices such as field-effect transistors, and storage capacitors. Significantly, solution-based compositions have attracted considerable attention as a highly effective and practical technique to replace vacuum-based process in large-area. Here, we demonstrate solution-processed composite films consisting of aluminum oxide (Al2O3) and boron nitride (BN), which exhibit remarkable dielectric properties through the optimization process. The leakage current of the optimized Al2O3-BN thin films was decreased by a factor of 100 at 3V, compared to pristine Al2O3 thin film without a loss of the dielectric constant or degradation of the morphological roughness. The characterization by X-ray photoelectron spectroscopy measurements revealed that the incorporation of BN with an optimized concentration into the Al2O3 dielectric film reduced the density of oxygen vacancies which act as defect states, thereby improving the dielectric characteristics.

Soil composition and nutritional status of apple as affected by long-term application of gypsum

Directory of Open Access Journals (Sweden)

Gilberto Nava

2012-02-01

Full Text Available Gypsum does not affect the soil negative charges and maintains sulfate in the soil solution, making it one of the cheapest products to increase Ca activity in soil solution, especially in the deeper soil layers. Higher Ca levels in the soil solution can increase the uptake of this nutrient by apple trees, reducing the risk of physiological disorders caused by Ca deficiency. This study assessed the effect of long-term gypsum application on some soil properties and on the chemical composition of leaves and fruits of an apple cultivar susceptible to fruit disorders associated with low Ca. The experiment was conducted in São Joaquim, in the South of Brazil, from 2001 to 2009. Gypsum rates of 0, 1.0, 2.0 and 3.0 t ha-1 were annually broadcast over the soil surface, without incorporation, in an apple orchard with cultivar ´Catarina´, planted in 1997. Gypsum application over eight consecutive years had no effect on soil exchangeable K and Al to a depth of 80 cm, but increased exchangeable Ca in the sampled layers (0-10, 10-20, 40-60 and 60-80 cm, while exchangeable Mg decreased only in the surface layer (0-20 cm. Gypsum did not affect the concentration of any nutrient in the fruits, including Ca. The same was verified in the leaves, except for Mg which decreased with increased gypsum rate. Despite increasing the availability of Ca in the soil profile to a depth of 80 cm, gypsum was not effective to increase the Ca content in leaves and fruits of an apple cultivar susceptible to Ca deficiency grown in an appropriately limed soil.

TiO2/bone composite materials for the separation of heavy metal impurities from waste water solutions

Science.gov (United States)

Dakroury, G.; Labib, Sh.; Abou El-Nour, F. H.

2012-09-01

Pure bone material obtained from cow meat, as apatite-rich material, and TiO2-bone composite materials are prepared and studied to be used for heavy metal ions separation from waste water solutions. Meat wastes are chemically and thermally treated to control their microstructure in order to prepare the composite materials that fulfill all the requirements to be used as selective membranes with high performance, stability and mechanical strength. The prepared materials are analyzed using Hg-porosimetry for surface characterization, energy dispersive X-ray spectroscopy (EDAX) for elemental analysis and Fourier transform infrared spectroscopy (FTIR) for chemical composition investigation. Structural studies are performed using X-ray diffraction (XRD). Microstructural properties are studied using scanning electron microscopy (SEM) and specific surface area studies are performed using Brunauer-Emmet-Teller (BET) method. XRD studies show that multiphase structures are obtained as a result of 1h sintering at 700-1200 °C for both pure bone and TiO2-bone composite materials. The factors affecting the transport of different heavy metal ions through the selected membranes are determined from permeation flux measurements. It is found that membrane pore size, membrane surface roughness and membrane surface charge are the key parameters that control the transport or rejection of heavy metal ions through the selected membranes.

The effect of flavoring oral rehydration solution on its composition and palatability.

Science.gov (United States)

te Loo, D Maroeska; van der Graaf, Fedde; Ten, Walther Tjon A

2004-11-01

As a number of mild to moderately dehydrated children refuse to drink oral rehydration solution (ORS) because of its strong salty taste, many parents and health workers flavor ORS with the childs favorite juice. The effects of flavoring ORS on electrolyte content and osmolality were assessed and the palatability of various solutions were compared with commercially flavored ORS. Osmolality, sodium, potassium, chloride and glucose content after flavoring with varying concentrations of apple juice, orange juice or orangeade was determined. Two of the solutions were offered to 30 children and adults to assess palatability. All additions to ORS (apple juice, orange juice or orangeade) caused a decrease of sodium (-30 to -53 mmol/L) and chloride (-27 to -47 mmol/L) content, whereas osmolality increased to greater than 311 mOsm/kg. These homemade oral rehydration solutions did not fulfill ESPGAN criteria for ORS, and rehydration will therefore be less effective. The majority of subjects also preferred the commercially flavored ORS. Only very small amounts of apple juice or orange juice can be added to the ORS without significantly altering electrolyte composition and osmolality. Palatability, however, does not improve compared with commercially flavored ORS. We therefore recommend using commercially flavored ORS, the composition of which fulfills ESPGAN criteria.

Self-assembly of poly(vinylidene fluoride–polystyrene block copolymers in solution: Effects of the length of polystyrene block and solvent compositions

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Yao Wu

2017-09-01

Full Text Available We report the first preliminary and extensive study on the solution self-assembly behaviors of poly(vinylidene fluoride–b-polystyrene (PVDF–PS block copolymers. The two PVDF–PS polymers we examined have the same length of PVDF block with number averaged repeating unit of 180, but distinctly different lengths of PS block with number averaged repeating unit of 125 and 1202. The self-assembly experiments were carried out in a series of mixture solutions containing a good solvent N,N-dimethylformamide and a selective solvent with different ratios. Our results showed that the self-assembly process was greatly affected by the two factors we examined, i.e. the length of the PS block and the solvent composition. We hope that our study could stimulate more research on the self-assembly of PVDF-containing polymers in solution.

Effect of soaking in water and rumen digeta solutions on metabolizable energy content and chemical composition of barley seeds for use in poultry diet.

Science.gov (United States)

Tabatabee, S N; Sadeghi, G H; Tabeidian, S A

2007-03-15

An experiment was carried out to evaluate the effect of soaking in water and different rumen digesta solutions on nutritional value of dry barley seeds. Treatments were included distilled water as control and rumen digesta that diluted with distilled water to obtain 20, 40 and 60% digesta solutions. Solutions have added to 10 kg of barley seed samples to achieve final 30% moisture content. After 21 days the chemical composition and energy content of barley seed were determined. Gross energy of barley seeds did not affected by different experimental treatments. Use of 20% rumen digesta solution resulted to a significant (pcontent of barley seeds. Barley seed that treated with 40% of rumen digesta solution had highest TME and TMEn content and its different from seeds that treated with 60 and 100% rumen digesta solutions was significant (prumen digesta solutions increased crud protein, ether extract, crude fiber and ash content of barley seeds numerically.

Preparation and application of attapulgite/iron oxide magnetic composites for the removal of U(VI) from aqueous solution

International Nuclear Information System (INIS)

Fan, Qiao-hui; Li, Ping; Chen, Yun-fei; Wu, Wang-suo

2011-01-01

Highlights: → We first synthesized ATP/IOM composites as an adsorbents for removal U(VI) from aqueous solution. → The sorption ability of ATP/IOM composites were obviously superior to ATP and iron oxides. → The prevalent species of U(VI) on ATP/IOM composites were =S s OUO 2 + and =S w OUO 2 (CO 3 ) 2 3- . → ATP/IOM composites could be a promising candidate for pre-concentration and immobilization of radionuclides from large volumes of aqueous solutions. - Abstract: Recently, magnetic sorbents have received considerable attention because of their excellent segregative features and sorption capacities. Herein, attapulgite/iron oxide magnetic (ATP/IOM) composites were prepared and characterized. The sorption results indicated that ATP/IOM composites were superior to ATP and iron oxides individually for the removal of U(VI) from aqueous solution. Based on X-ray photoelectron spectroscopy (XPS) analysis and surface complexation model, the main sorption species of U(VI) on ATP were =X 2 UO 2 0 below pH 4.0 and =S s OUO 2 + , =S w OUO 2 CO 3 - , and =S w OUO 2 (CO 3 ) 2 3- above pH 5.0. However the prevalent species on ATP/IOM composites were =S s OUO 2 + and =S w OUO 2 (CO 3 ) 2 3- over the observed pH range. ATP/IOM composites are a promising candidate for pre-concentration and immobilization of radionuclides from large volumes of aqueous solutions, as required for remediation purposes.

Dielectric and Piezoelectric Properties of PZT Composite Thick Films with Variable Solution to Powder Ratios.

Science.gov (United States)

Wu, Dawei; Zhou, Qifa; Shung, Koping Kirk; Bharadwaja, Srowthi N; Zhang, Dongshe; Zheng, Haixing

2009-05-08

The use of PZT films in sliver-mode high-frequency ultrasonic transducers applications requires thick, dense, and crack-free films with excellent piezoelectric and dielectric properties. In this work, PZT composite solutions were used to deposit PZT films >10 μm in thickness. It was found that the functional properties depend strongly on the mass ratio of PZT sol-gel solution to PZT powder in the composite solution. Both the remanent polarization, P(r), and transverse piezoelectric coefficient, e(31,) (f), increase with increasing proportion of the sol-gel solution in the precursor. Films prepared using a solution-to-powder mass ratio of 0.5 have a remanent polarization of 8 μC/cm(2), a dielectric constant of 450 (at 1 kHz), and e(31,) (f) = -2.8 C/m(2). Increasing the solution-to-powder mass ratio to 6, the films were found to have remanent polarizations as large as 37 μC/cm(2), a dielectric constant of 1250 (at 1 kHz) and e(31,) (f) = -5.8 C/m(2).

Agricultural matrices affect ground ant assemblage composition inside forest fragments.

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Diego Santana Assis

Full Text Available The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates; sugarcane (3; and pasture (3. At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart. Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

Agricultural matrices affect ground ant assemblage composition inside forest fragments.

Science.gov (United States)

Assis, Diego Santana; Dos Santos, Iracenir Andrade; Ramos, Flavio Nunes; Barrios-Rojas, Katty Elena; Majer, Jonathan David; Vilela, Evaldo Ferreira

2018-01-01

The establishment of agricultural matrices generally involves deforestation, which leads to fragmentation of the remaining forest. This fragmentation can affect forest dynamics both positively and negatively. Since most animal species are affected, certain groups can be used to measure the impact of such fragmentation. This study aimed to measure the impacts of agricultural crops (matrices) on ant communities of adjacent lower montane Atlantic rainforest fragments. We sampled nine forest fragments at locations surrounded by different agricultural matrices, namely: coffee (3 replicates); sugarcane (3); and pasture (3). At each site we installed pitfall traps along a 500 m transect from the interior of the matrix to the interior of the fragment (20 pitfall traps ~25 m apart). Each transect was partitioned into four categories: interior of the matrix; edge of the matrix; edge of the fragment; and interior of the fragment. For each sample site, we measured ant species richness and ant community composition within each transect category. Ant richness and composition differed between fragments and matrices. Each sample location had a specific composition of ants, probably because of the influence of the nature and management of the agricultural matrices. Species composition in the coffee matrix had the highest similarity to its corresponding fragment. The variability in species composition within forest fragments surrounded by pasture was greatest when compared with forest fragments surrounded by sugarcane or, to a lesser extent, coffee. Functional guild composition differed between locations, but the most representative guild was 'generalist' both in the agricultural matrices and forest fragments. Our results are important for understanding how agricultural matrices act on ant communities, and also, how these isolated forest fragments could act as an island of biodiversity in an 'ocean of crops'.

Nutrients affecting brain composition and behavior

Science.gov (United States)

Wurtman, R. J.

1987-01-01

This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

Biofilm formation affects surface properties of novel bioactive glass-containing composites.

Science.gov (United States)

Hyun, Hong-Keun; Salehi, Satin; Ferracane, Jack L

2015-12-01

This study investigated the effects of bacterial biofilm on the surface properties of novel bioactive glass (BAG)-containing composites of different initial surface roughness. BAG (65 mol% Si; 4% P; 31% Ca) and BAG-F (61% Si; 31% Ca; 4% P; 3% F; 1% B) were synthesized by the sol-gel method and micronized (size ∼0.1-10 μm). Composites with 72wt% total filler load were prepared by replacing 15% of the silanized Sr glass with BAG, BAG-F, or silanized silica. Specimens (n=10/group) were light-cured and divided into 4 subgroups of different surface roughness by wet polishing with 600 and then up to 1200, 2400, or 4000 grit SiC. Surface roughness (SR), gloss, and Knoop microhardness were measured before and after incubating in media with or without a Streptococcus mutans (UA 159) biofilm for 2 weeks. Results were analyzed with ANOVA/Tukey's test (α=0.05). The SR of the BAG-containing composites with the smoothest surfaces (2400/4000 grit) increased in media or bacteria; the SR of the roughest composites (600 grit) decreased. The gloss of the smoothest BAG-containing composites decreased in bacteria and media-only, but more in media-alone. The microhardness of all of the composites decreased with exposure to media or bacteria, with BAG-containing composites affected more than the control. Exposure to bacterial biofilm and its media produced enhanced roughness and reduced gloss and surface microhardness of highly polished dental composites containing a bioactive glass additive, which could affect further biofilm formation, as well as the esthetics, of restorations made from such a material. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Removal of Congo red dye from aqueous solutions using a halloysite-magnetite-based composite.

Science.gov (United States)

Ferrarini, F; Bonetto, L R; Crespo, Janaina S; Giovanela, M

2016-01-01

Adsorption has been considered as one of the most effective methods to remove dyes from aqueous solutions due to its ease of operation, high efficiency and wide adaptability. In view of all these aspects, this study aimed to evaluate the adsorption capacity of a halloysite-magnetite-based composite in the removal of Congo red dye from aqueous solutions. The effects of stirring rate, pH, initial dye concentration and contact time were investigated. The results revealed that the adsorption kinetics followed the pseudo-second-order model, and equilibrium was well represented by the Brunauer-Emmett-Teller isotherm. The thermodynamic data showed that dye adsorption onto the composite was spontaneous and endothermic and occurred by physisorption. Finally, the composite could also be regenerated at least four times by calcination and was shown to be a promising adsorbent for the removal of this dye.

Influence of material and solution composition on the extrusion/erosion behaviour of compacted bentonite

International Nuclear Information System (INIS)

Schatz, Timothy; Martikainen, Jari; Koskinen, Kari

2010-01-01

Document available in extended abstract form only. In principle, in a KBS-3 type repository, the volume of a deposition hole is fixed and the bentonite buffer mass accordingly balanced to lead to the development of a suitable swelling pressure upon saturation. However, fractures intersecting the deposition holes give rise to the possibility that volume constrained conditions do not universally exist. Such fractures may provide pathways for the continued, localised, free swelling of bentonite buffer material. Loss of mass from the deposition hole by extrusion into intersecting fractures may compromise the long-term safety and performance of the buffer component of the engineered barrier system. Furthermore, the continued hydration and expansion of extruded bentonite in these fracture environments could lead to the separation of colloid-sized (or larger) particles by diffusion or shear which may have to be accounted for in possible radionuclide migration scenarios. Geochemical conditions, with respect to both solution and material composition, are considered to play important roles regarding the fracture extrusion/erosion of bentonite buffer material. For example, calcium-montmorillonite exhibits limited free swelling relative to sodium-montmorillonite and the colloidal and rheological properties of montmorillonite dispersions are sensitive to the presence of electrolytes. Insofar as both the buffer material composition (due to ion exchange) and groundwater composition (dilution resulting from infiltration of glacial melt water) are expected to evolve with time, so too might the potential for fracture extrusion/erosion of buffer material vary over time. The hydraulic characteristics of the intersecting fracture are expected to influence the extrusion/erosion process as well. To evaluate the effect of material and solution composition on the potential for extrusion of buffer mass into intersecting fractures, a series of batch experiments were performed. In these

Investigation of Different Colloidal Porous Silicon Solutions and Their Composite Solid Matrix Rods by Optical Techniques

Science.gov (United States)

Khan, M. Naziruddin; Aldalbahi, Ali; Almohammedi, Abdullah

2018-03-01

Colloidal porous silicon (PSi) in different solvents was synthesized by simple chemical etching. Colloidal solutions were then prepared using different quantities of silicon wafer pieces (Pcs) and chloroplatinic (Pt) acid in catalyst solution. The effect on the properties of the colloidal solutions and composite rods were investigated using various optical characterization techniques. Absorption and photoluminescence (PL) intensity of the colloidal PSi solutions are observed to depend on the quantity of wafer Pcs, the Pt-solution, and the porosity formation on the wafer surface. The morphological structure of the PSi in a solvent and the solid-rod environments were studied using field-emission scanning electron microscopy (FE-SEM) and were observed to have different structures. A mono-oriented structure of PSi exists in tetrahydrofuran, which has stereo orientation in dioxane and dimethylsulfoxide (approximately 5-8 nm as confirmed using high resolution transmission electron microscopy). Subsequently, some colloidal PSi solutions were directly embedded in three types of sol-gel-based matrices, silica, ormosils (or organically modified silica) and polymer, which easily generated solid rods. Spontaneous emission (SE) of the PSi solutions and their composite rods were examined using a high power picosecond 355 nm laser source. The emitted PL and SE signals of the colloidal PSi solutions were dependent on the Pt volume, nature of the solvent, quantity of Si wafer piece, and pumping energy. The response of SE signals from the PSi composites rods is an interesting phenomenon, and such nanocomposites may be used for future research on light amplification.

An Analytical Solution for Transient Heat Conduction in a Composite Slab with Time-Dependent Heat Transfer Coefficient

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Ryoichi Chiba

2018-01-01

Full Text Available An analytical solution is derived for one-dimensional transient heat conduction in a composite slab consisting of n layers, whose heat transfer coefficient on an external boundary is an arbitrary function of time. The composite slab, which has thermal contact resistance at n-1 interfaces, as well as an arbitrary initial temperature distribution and internal heat generation, convectively exchanges heat at the external boundaries with two different time-varying surroundings. To obtain the analytical solution, the shifting function method is first used, which yields new partial differential equations under conventional types of external boundary conditions. The solution for the derived differential equations is then obtained by means of an orthogonal expansion technique. Numerical calculations are performed for two composite slabs, whose heat transfer coefficient on the heated surface is either an exponential or a trigonometric function of time. The numerical results demonstrate the effects of temporal variations in the heat transfer coefficient on the transient temperature field of composite slabs.

Corrosion behavior of aluminum-alumina composites in aerated 3.5 percent chloride solution

Science.gov (United States)

Acevedo Hurtado, Paul Omar

Aluminum based metal matrix composites are finding many applications in engineering. Of these Al-Al2O3 composites appear to have promise in a number of defense applications because of their mechanical properties. However, their corrosion behavior remains suspect, especially in marine environments. While efforts are being made to improve the corrosion resistance of Al-Al2O3 composites, the mechanism of corrosion is not well known. In this study, the corrosion behavior of powder metallurgy processed Al-Cu alloy reinforced with 10, 15, 20 and 25 vol. % Al2O3 particles (XT 1129, XT 2009, XT 2048, XT 2031) was evaluated in aerated 3.5% NaCl solution using microstructural and electrochemical measurements. AA1100-O and AA2024T4 monolithic alloys were also studied for comparison purposes. The composites and unreinforced alloys were subjected to potentiodynamic polarization and Electrochemical Impedance Spectroscopy (EIS) testing. Addition of 25 vol. % Al2O 3 to the base alloys was found to increase its corrosion resistance considerably. Microstructural studies revealed the presence of intermetallic Al2Cu particles in these composites that appeared to play an important role in the observations. Pitting potential for these composites was near corrosion potential values, and repassivation potential was below the corresponding corrosion potential, indicating that these materials begin to corrode spontaneously as soon as they come in contact with the 3.5 % NaCl solution. EIS measurements indicate the occurrence of adsorption/diffusion phenomena at the interface of the composites which ultimately initiate localized or pitting corrosion. Polarization resistance values were extracted from the EIS data for all the materials tested. Electrically equivalent circuits are proposed to describe and substantiate the corrosive processes occurring in these Al-Al2O 3 composite materials.

Analytical solution for heat conduction problem in composite slab and its implementation in constructal solution for cooling of electronics

International Nuclear Information System (INIS)

Kuddusi, Luetfullah; Denton, Jesse C.

2007-01-01

The constructal solution for cooling of electronics requires solution of a fundamental heat conduction problem in a composite slab composed of a heat generating slab and a thin strip of high conductivity material that is responsible for discharging the generated heat to a heat sink located at one end of the strip. The fundamental 2D heat conduction problem is solved analytically by applying an integral transform method. The analytical solution is then employed in a constructal solution, following Bejan, for cooling of electronics. The temperature and heat flux distributions of the elemental heat generating slabs are assumed to be the same as those of the analytical solution in all the elemental volumes and the high conductivity strips distributed in the different constructs. Although the analytical solution of the fundamental 2D heat conduction problem improves the accuracy of the distributions in the elemental slabs, the results following Bejan's strategy do not affirm the accuracy of Bejan's constructal solution itself as applied to this problem of cooling of electronics. Several different strategies are possible for developing a constructal solution to this problem as is indicated

Preparation of modified polymer- Alumino silicate composite and their application in removal of some radionuclides from aqueous solutions

International Nuclear Information System (INIS)

El- Masry, E.H.

2012-01-01

Ion exchange is one of the most common and effective treatment methods for radioactive liquid waste. This technique is well developed and has been employed for many years in both the nuclear industry and in other industries. In this thesis polyacrylamide- zeolite and polyacrylamide- bentonite composites were prepared and characterized using advanced analytical techniques. The prepared materials were used as composite ion exchangers for removal of Cesium, Cobalt and Strontium ions from simulated waste solution. Effect of ph of the medium on the removal of aforementioned ions was investigated. The sorption kinetic was studied and the data were analyzed by different kinetic models which rivaled that the mechanism of the sorption processes is mainly controlled by pseudo-second order reaction, and particle diffusion might be involved in the sorption processes. The values of diffusion coefficient of the three metal ions were calculated and suggested that chemisorption was the predominated sorption mechanism. Several isotherm models were applied for the sorption, and thermodynamic parameters were determined. The positive values of enthalpy change, δH, for the three metal ions confirmed the endothermic nature of the sorption processes. The results indicated that the prepared materials can be used as efficient ion exchange materials for the removal of cesium, cobalt and strontium ions from simulated waste solution. In the present study, immobilization of polyacrylamide- zeolite and/ or polyacrylamide- bentonite composites loaded with cesium, cobalt and/or strontium radionuclides with Ordinary Portland Cement (OPC) has been carried out. Several factors affecting the characteristics of the final solidified waste product towards safe disposal such as mechanical strength and leaching behavior of the radioisotopes have been studied. The obtained results showed that the presence of polyacrylamide- zeolite and/ or polyacrylamide- bentonite composites in the cemented wastes

Temperature and curing time affect composite sorption and solubility

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Fabrício Luscino Alves de Castro

2013-04-01

Full Text Available Objective: This study evaluated the effect of temperature and curing time on composite sorption and solubility. Material and Methods: Seventy five specimens (8×2 mm were prepared using a commercial composite resin (ICE, SDI. Three temperatures (10°C, 25°C and 60°C and five curing times (5 s, 10 s, 20 s, 40 s and 60 s were evaluated. The specimens were weighed on an analytical balance three times: A: before storage (M1; B: 7 days after storage (M2; C: 7 days after storage plus 1 day of drying (M3. The storage solution consisted of 75% alcohol/25% water. Sorption and solubility were calculated using these three weights and specimen dimensions. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U Tests (α=5%. Results: The results showed that time, temperature and their interaction influenced the sorption and solubility of the composite (p0.05. The 60°C composite temperature led to lower values of sorption for all curing times when compared with the 10°C temperature (p0.05. Solubility was similar at 40 s and 60 s for all temperatures (p>0.05, but was higher at 10°C than at 60°C for all curing times (p0.05. Conclusions: In conclusion, higher temperatures or longer curing times led to lower sorption and solubility values for the composite tested; however, this trend was only significant in specific combinations of temperature and curing times.

Effect of staining solutions and repolishing on color stability of direct composites

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Fabrício Mariano Mundim

2010-06-01

Full Text Available OBJECTIVES: The purpose of this study was to assess the color change of three types of composite resins exposed to coffee and cola drink, and the effect of repolishing on the color stability of these composites after staining. MATERIALS AND METHODS: Fifteen specimens (15 mm diameter and 2 mm thick were fabricated from microhybrid (Esthet-X; Dentsply and Filtek Z-250; 3M ESPE and high-density hybrid (Surefil; Dentsply composites, and were finished and polished with aluminum oxide discs (Sof-Lex; 3M ESPE. Color of the specimens was measured according to the CIE L*a*b* system in a refection spectrophotometer (PCB 6807; BYK Gardner. After baseline color measurements, 5 specimens of each resin were immersed in different staining solutions for 15 days: G1 - distilled water (control, G2 - coffee, G3 - cola soft drink. Afterwards, new color measurement was performed and the specimens were repolished and submitted to new color reading. Color stability was determined by the difference (ΔE between the coordinates L*, a*, and b* obtained from the specimens before and after immersion into the solutions and after repolishing. RESULTS: There was no statistically signifcant difference (ANOVA, Tukey's test; p>0.05 among the ΔE values for the different types of composites after staining or repolishing. For all composite resins, coffee promoted more color change (ΔE>3.3 than distilled water and the cola soft drink. After repolishing, the ΔE values of the specimens immersed in coffee decreased to clinically acceptable values (ΔE<3.3, but remained signifcantly higher than those of the other groups. CONCLUSIONS: No signifcant difference was found among composite resins or between color values before and after repolishing of specimens immersed in distilled water and cola. Immersing specimens in coffee caused greater color change in all types of composite resins tested in this study and repolishing contributed to decrease staining to clinically acceptable �

Effect of Solution Treatment Process on Hardness of Alumina Reinforced Al-9Zn Composite Produced by Squeeze Casting

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Dwi Rahmalina

2014-10-01

Full Text Available Characteristics of aluminium matrix composites reinforced by alumina have been developed to improve mechanical properties. One of the determining factors in the development of this material is parameter of solution treatment process. This study discusses the performance of the composite matrix of Al-9Zn-6Mg-3Si reinforced by alumina powder of 5 % volume fraction. Composite are manufactured by squeeze casting process with the pressure of 20 Ton in the metal mould. To improve mechanical properties, the precipitation hardening process is conducted through variation of temperature of solution treatment of 450, 475 and 500 °C and holding time of solution treatment of 30, 60 and 90 minutes. Materials are characterized by hardness testing and microstructure observation. The results showed that the optimum condition of hardness was produced by solution treatment temperature of 500 °C and 90 minutes holding time of 86 HRB.

In vitro behaviour of three biocompatible glasses in composite implants.

Science.gov (United States)

Varila, Leena; Lehtonen, Timo; Tuominen, Jukka; Hupa, Mikko; Hupa, Leena

2012-10-01

Poly(L,DL-lactide) composites containing filler particles of bioactive glasses 45S5 and S53P4 were compared with a composite containing a slowly dissolving glass S68. The in vitro reactivity of the composites was studied in simulated body fluid, Tris-buffered solution, and phosphate buffered saline. The high processing temperature induced thermal degradation giving cavities in the composites containing 45S5 and S53P4, while good adhesion of S68 to the polymer was observed. The cavities partly affected the in vitro reactivity of the composites. The degradation of the composites containing the bioactive glasses was faster in phosphate buffered saline than in the two other solutions. Hydroxyapatite precipitation suggesting bone tissue bonding capability was observed on these two composites in all three solutions. The slower dissolution of S68 glass particles and the limited hydroxyapatite precipitation suggested that this glass has potential as a reinforcing composition with the capability to guide bone tissue growth in biodegradable polymer composites.

A model based bayesian solution for characterization of complex damage scenarios in aerospace composite structures.

Science.gov (United States)

Reed, H; Leckey, Cara A C; Dick, A; Harvey, G; Dobson, J

2018-01-01

Ultrasonic damage detection and characterization is commonly used in nondestructive evaluation (NDE) of aerospace composite components. In recent years there has been an increased development of guided wave based methods. In real materials and structures, these dispersive waves result in complicated behavior in the presence of complex damage scenarios. Model-based characterization methods utilize accurate three dimensional finite element models (FEMs) of guided wave interaction with realistic damage scenarios to aid in defect identification and classification. This work describes an inverse solution for realistic composite damage characterization by comparing the wavenumber-frequency spectra of experimental and simulated ultrasonic inspections. The composite laminate material properties are first verified through a Bayesian solution (Markov chain Monte Carlo), enabling uncertainty quantification surrounding the characterization. A study is undertaken to assess the efficacy of the proposed damage model and comparative metrics between the experimental and simulated output. The FEM is then parameterized with a damage model capable of describing the typical complex damage created by impact events in composites. The damage is characterized through a transdimensional Markov chain Monte Carlo solution, enabling a flexible damage model capable of adapting to the complex damage geometry investigated here. The posterior probability distributions of the individual delamination petals as well as the overall envelope of the damage site are determined. Copyright © 2017 Elsevier B.V. All rights reserved.

Elemental composition changes in citrus affected by the CVC disease

International Nuclear Information System (INIS)

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

2008-01-01

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

Anisotropic perylenediimide/polycarbonate composites produced by a single batch solution based method

Energy Technology Data Exchange (ETDEWEB)

Dobruchowska, Ewa, E-mail: ewa.dobruchowska@tu.koszalin.pl [Department of Molecular Physics, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland); Institute of Technology and Education, Koszalin University of Technology, Sniadeckich 2, 75-453 Koszalin (Poland); Marszalek, Tomasz; Ulanski, Jacek [Department of Molecular Physics, Technical University of Lodz, Zeromskiego 116, 90-924 Lodz (Poland)

2014-08-01

The continuous anisotropic organic semiconductor/dielectric composites consisting of a top, unidirectionally oriented crystalline layer of perylenediimide derivative (2,9-di(pent-3-yl)-anthra[1,9-def:6,5,10-d′e′f′]diisoquinoline-1,3,8, 10-tetrone) (PTCDI-C5(3)) and a bottom layer of poly(bisphenol A carbonate) (PC) support were obtained in a one batch solution process, with the use of the so called the zone-casting method. Scanning electron microscopy images have shown that the top PTCDI-C5(3) layer is made of long, parallel crystallites in the form of ribbons that exhibit birefringence when placed between a pair of crossed polarisers in the optical microscope. Furthermore, the polarised UV–Vis absorbance and photoluminescence experiments revealed that the alignment of the PTCDI-C5(3) molecules is caused by π–π interactions between the conjugated perylene cores, and their stacks are parallel to the long axis of the crystallites and to the polymer surface. The high value of the calculated polarisation ratio, which equals 0.64, constitutes a confirmation of a high degree of molecular order within the semiconducting component of the zone-cast composites. - Highlights: • Bi-layer composites were produced by a single batch solution based method. • The top-layer was made of an n-type organic semiconductor — perylene derivative. • Polarised absorbance and photoluminescence were used to study optical anisotropy. • High polarisation ratio of 0.64 was obtained for the top-layer of the composite.

Characteristics of regenerated nanocellulosic fibers from cellulose dissolution in aqueous solutions for wood fiber/polypropylene composites

Science.gov (United States)

Sangyeob Lee; Hui Pan; Chung Y. Hse; Alfred R. Gunasekaran; Todd F. Shupe

2014-01-01

The effects of aqueous solutions were evaluated on the properties of regenerated cellulosic nanofibers prepared from pure cellulose fibers in various formulations of aqueous solutions. Thermoplastic composites were prepared with reinforcement of the regenerated cellulosic nanofibers. The regenerated cellulosic fibers from cellulosic woody biomass were obtained from...

The influence of precipitation temperature on the properties of ceria–zirconia solid solution composites

International Nuclear Information System (INIS)

Cui, Yajuan; Fang, Ruimei; Shang, Hongyan; Shi, Zhonghua; Gong, Maochu; Chen, Yaoqiang

2015-01-01

Highlights: • The crystallite size of precipitate increases as the precipitation temperature rises. • The stack of large crystallite can form nanoparticles with big pore size. • Big pore sizes are advantageous to improve the thermal stability. • Phase segregation is restricted in CZ solid solution precipitated at 70 °C. • The reducibility and OSC of the solid solution precipitated at 70 °C are improved. - Abstract: The ceria–zirconia composites (CZ) with a Ce/Zr mass ratio of 1/1 were synthesized by a back-titration method, in which the influence of precipitation temperature on the properties of ceria–zirconia precipitates was investigated. The resulting precipitation and mixed oxides at different precipitation temperatures were then characterized by a range of techniques, including textural properties, X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), H 2 -temperature programmed reduction (H 2 -TPR) as well as oxygen storage capacity (OSC) measurement. The results revealed that ceria–zirconia composites were formed as solid solution and such structure is favored of thermostability and texture properties. In particular, the composite CZ-70 synthesized at 70 °C exhibited prominent thermostability with a surface area of 32 m 2 /g as well as a pore volume of 0.15 cc/g after aging treatment at 1000 °C for 5 h. And this was found to be associated with the wider pore size distribution which maybe owed to the formation of large crystal at the primary stage of precipitation. Additionally, the composite CZ-70 showed excellent reduction property and OSC benefiting from stable texture and structure

Optimization of strontium adsorption from aqueous solution using (mn-Zr) oxide-pan composite spheres

International Nuclear Information System (INIS)

Inan, S.; Altas, Y.

2009-01-01

The processes based on adsorption and ion exchange have a great role for the pre-concentration and separation of toxic, long lived radionuclides from liquid waste. In Nuclear waste management, the removal of long lived, radiotoxic isotopes from radioactive waste such as strontium reduces the storage problems and facilitates the disposal of the waste. Depending on the waste type, a variety of adsorbents and/or ion exchangers are used. Due to the amorphous structure of hydrous oxides and their mixtures, they don't have reproducible properties. Besides, obtained powders are very fine particles and they can cause operational problems such as pressure drop and filtration. Therefore they are not suitable for column applications. These reasons have recently expedited the study on the preparation of organic-inorganic composite adsorbent beads for industrial applications. PAN, as a stable and porous support for fine particles, provides the utilization of ion exchangers in large scale column applications. The utilization of PAN as a support material with many inorganic ion exchangers was firstly achieved by Sebesta in the beginning of 1990's. Later on, PAN based composite ion exchangers were prepared and used for the removal of radionuclides and heavy metal ions from aqueous solution and waste waters. In this study, spherical (Mn-Zr)oxide-PAN composite were prepared for separation of strontium from aqueous solution in a wide pH range. Sr 2 + adsorption of composite adsorbent was optimized by using experimental design 'Central Composite Design' model.

Derivative spectrophotometry applied to solutions of complex composition

International Nuclear Information System (INIS)

Perfil'ev, V.A.

1986-01-01

The authors consider not only the basic principles of derivative spectrophotometry but also survey the data on its use in research on the properties of materials, the compositions of compounds, and the structures of complex chemical systems. Recording methods by which derivative spectra can be generated include descriptions of electronic differentiation, computer spectrum differentiation, wavelength modulation, and the two-way derivative method. A section on the advantages of derivative spectrophotometry presents a discussion on features enabling one to determine various substances from their characteristic absorption spectra without performing complicated operations to isolate or separate the components. Other topics include research on the structures of substances and metal-ion complexing in solutions, derivative spectrophotometry in gas analysis, gas determination, and determining organic and compounds

Chemical composition and Zn bioavailability of the soil solution extracted from Zn amended variable charge soils.

Science.gov (United States)

Zampella, Mariavittoria; Adamo, Paola

2010-01-01

A study on variable charge soils (volcanic Italian and podzolic Scottish soils) was performed to investigate the influence of soil properties on the chemical composition of soil solution. Zinc speciation, bioavailability and toxicity in the soil solution were examined. The soils were spiked with increasing amounts of Zn (0, 100, 200, 400 and 1000 mg/kg) and the soil solutions were extracted using rhizon soil moisture samplers. The pH, total organic carbon (TOC), base cations, anions, total Zn and free Zn2+ in soil solution were analysed. A rapid bioassay with the luminescent bacterium Escherichia coli HB101 pUCD607 was performed to assess Zn toxicity. The influence of soil type and Zn treatments on the chemical composition of soil solution and on Zn toxicity was considered and discussed. Different trends of total and free Zn concentrations, base cations desorption and luminescence of E. coli HB101 pUCD607 were observed. The soil solution extracted from the volcanic soils had very low total and free Zn concentrations and showed specific Zn2+/Ca2+ exchange. The soil solution from the podzolic soil had much higher total and free Zn concentrations and showed no evidence of specific Zn2+/Ca2+ exchange. In comparison with the subalkaline volcanic soils, the acidic podzol showed enhanced levels of toxic free Zn2+ and consequently stronger effects on E. coli viability.

Agar composition affects in vitro screening of biocontrol activity of antagonistic microorganisms

NARCIS (Netherlands)

Bosmans, Lien; De Bruijn, I.; de Mot, Rene; Readers, Hans; Lievens, Bart

2016-01-01

Agar-based screening assays are the method of choice when evaluating antagonistic potential of bacterial biocontrol-candidates against pathogens.Weshowed thatwhen using the samemedium, but different agar compositions, the activity of a bacterial antagonist against Agrobacteriumwas strongly affected.

Sandwich Structured Composites for Aeronautics: Methods of Manufacturing Affecting Some Mechanical Properties

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Aneta Krzyżak

2016-01-01

Full Text Available Sandwich panels are composites which consist of two thin laminate outer skins and lightweight (e.g., honeycomb thick core structure. Owing to the core structure, such composites are distinguished by stiffness. Despite the thickness of the core, sandwich composites are light and have a relatively high flexural strength. These composites have a spatial structure, which affects good thermal insulator properties. Sandwich panels are used in aeronautics, road vehicles, ships, and civil engineering. The mechanical properties of these composites are directly dependent on the properties of sandwich components and method of manufacturing. The paper presents some aspects of technology and its influence on mechanical properties of sandwich structure polymer composites. The sandwiches described in the paper were made by three different methods: hand lay-up, press method, and autoclave use. The samples of sandwiches were tested for failure caused by impact load. Sandwiches prepared in the same way were used for structural analysis of adhesive layer between panels and core. The results of research showed that the method of manufacturing, more precisely the pressure while forming sandwich panels, influences some mechanical properties of sandwich structured polymer composites such as flexural strength, impact strength, and compressive strength.

All-solution processed composite hole transport layer for quantum dot light emitting diode

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaoli [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300072 (China); Synergetic Innovation Center of Chemical Science and Engineering, Tianjin (China); Dai, Haitao, E-mail: htdai@tju.edu.cn [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300072 (China); Zhao, Junliang; Wang, Shuguo [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Science, Tianjin University, Tianjin 300072 (China); Sun, Xiaowei [Department of Electrical & Electronic Engineering, South University of Science and Technology of China, Tangchang Road 1088, Shenzhen, Guangdong 518055 (China)

2016-03-31

In the present work, poly-TPD and TCTA composite hole transport layer (HTL) was employed in solution processed CdSe/ZnS quantum dot light emitting diodes (QLEDs). As the doping level of TCTA can determine the carriers transport efficiency of HTL, the proper mixing ratio of TCTA and poly-TPD should be found to optimize the performance of composite HTL for QLEDs. The doping of poly-TPD by low TCTA content can make its HOMO level lower and then reduce the energy barrier height from HTL to quantum dots (QDs), whereas the doping of poly-TPD by the concentrated TCTA results in the degraded performance of QLEDs due to its decreased hole transport mobility. By using the optimized composition with poly-TPD:TCTA (3:1) as the hole transport layer, the luminescence of the device exhibits about double enhancement compared with that of poly-TPD based device. The improvement of luminescence is mainly attributed to the lower energy barrier of hole injection. The Förster resonant energy transfer (FRET) mechanism in the devices was investigated through theoretical and experimental analysis and the results indicate that the TCTA doping makes no difference on FRET. Therefore, the charge injection mechanism dominates the improved performance of the devices. - Highlights: • Quantum dot light emitting diodes (QLEDs) were fabricated by all solution method. • The performance of QLEDs was optimized by varying the composite hole transport layer. • The blend HTL could promote hole injection by optimizing HOMO levels. • The energy transfer mechanism was analyzed by studying Förster resonant energy transfer process.

Preparation of SiO2-KCoFC composite ion-exchanger for removal of Cs in the soil decontamination waste solution

International Nuclear Information System (INIS)

Lee, Jung Joon; Moon, Jei kwon; Lee, Kune Woo

2009-01-01

The soil decontamination process has been developed for remediate the soil wastes excavated from the TRIGA research reactor sites. Even though the process was proven to be very effective for decontaminate the radioactive nuclides such as cesium and cobalt, the secondary spent solution should be treated with an appropriate method to minimize the waste volume. There are mainly two components in the spent decontamination solution of Cs and Co. The Co in the waste solution can be removed easily by precipitation under a basic condition. However, since the Cs is hardly removed by precipitation, an appropriate selective removal method should be employed. In this study, an inorganic composite ion exchanger of SiO 2 -KCoFC was prepared by sol-gel method for a removal of Cs in the decontamination waste solution. An optimum condition for a preparation of the composite ion exchanger and the adsorption performances of the prepared composite ion exchangers were evaluated

Earliest Results in the Use of Activated Composite Membranes for the Transport of Silver Ions from Aqueous Solutions

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Yucundo Mendoza-Tolentino

2014-01-01

Full Text Available This paper presents the results concerning the first use of activated composite membranes (ACMs for the facilitated transport of silver ions containing di-(2-ethylhexyl-dithiophosphoric acid (DTPA as the carrier. DTPA was immobilized by interfacial polymerization in a dense layer that was deposited in a porous layer, which was prepared on a nonwoven fabric support by phase inversion. The influence of fundamental parameters affecting the transport of silver ion as the carrier concentration in the membrane phase and stripping agent variation of the stripping solution have been studied. In the optimal conditions, the amount of silver transported across the ACMs was greater than 50%, whereas if the content of the carrier is modified, more than the 90% of the initial silver is removed from the feed phase.

Economical bridge solutions based on innovative composite dowels and integrated abutments ecobridge

CERN Document Server

Băncilă, Radu

2015-01-01

This book is an outcome of the research project “ECOBRIDGE – Demonstration of ECOnomical BRIDGE solutions based on innovative composite dowels and integrated abutments – RFCS – CT 2010-00024”, which has been co-funded by the Research Fund for Coal and Steel (R.F.C.S.) of the European Community. The main topics of the book are the following: design of integral bridges, innovative composite dowels for the shear transmission, construction of bridges, structural analysis of bridges and monitoring. The book joins the technical experience and the contributions of the involved research partners. The technical content of all the papers is present-day in the field of the design, construction and monitoring of innovative composite bridges. The efficient design and construction improve and consolidate the market position of steel construction and steel producing industry. In addition, the advanced forms of construction are contributing to savings in material and energy consumption for the structure during prod...

The chemistry of salt-affected soils and waters

Science.gov (United States)

Knowledge of the chemistry of salt affected soils and waters is necessary for management of irrigation in arid and semi-arid regions. In this chapter we review the origin of salts in the landscape, the major chemical reactions necessary for prediction of the soil solution composition, and the use of...

AN EXACT ELASTO-PLASTIC SOLUTION OF METAL-MATRIX COMPOSITE CANTILEVER BEAM LOADED BY A SINGLE FORCE AT ITS FREE END

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Onur SAYMAN

2001-03-01

Full Text Available In the present study, an elastic-plastic stress analysis is carried out in a metal matrix composite cantilever beam loaded by a single force at its free end. A composite consisting of stainless-steel reinforced aluminium was produced for this work. The orientation angle of the fibers is chosen as 0°, 30°, 45°, 60° and 90°. The material is assumed to be perfectly plastic in the elasto-plastic solution. An analytical solution is performed for satisfying both the governing differential equation in the plane stress case and boundary conditions for small plastic deformations. The solution is carried out under the assumption of the Bernoulli-Navier hypotheses. The composite material is assumed as hardening linearly. The Tsai-Hill theory is used as a yield criterion.

Studies on synthesis of some composites and their uses for cesium separation

International Nuclear Information System (INIS)

Someda, H.H.; El-Zahhar, A.A.; Shehata, M.K.K.; El-Naggar, H.A.

2002-01-01

In this study some composite sorbents were prepared by supporting hexacyanoferrate complexes of some transition metals like Co, Ni, Fe and Zn on some different solid supports e.g. cellulose and other natural materials as wood powder. These composites were used for cesium sorption and showed that the highest sorption capacity is for zinc composite and the lowest is for cobalt composite. Also the factors affecting the sorption capacity like acid concentration, competing ions and cesium ion concentration were studied. The release of the sorbed cesium from the composite materials was also studied under different concentrations of different solutions like sodium nitrate, silver nitrate, ammonium nitrate and a mixture of ammonium nitrate and silver nitrate solutions

One-parameter families of supersymmetric isospectral potentials from Riccati solutions in function composition form

Energy Technology Data Exchange (ETDEWEB)

Rosu, Haret C., E-mail: hcr@ipicyt.edu.mx [IPICYT, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la presa San José 2055, Col. Lomas 4a Sección, 78216 San Luis Potosí, S.L.P. (Mexico); Mancas, Stefan C., E-mail: mancass@erau.edu [Department of Mathematics, Embry–Riddle Aeronautical University, Daytona Beach, FL 32114-3900 (United States); Chen, Pisin, E-mail: pisinchen@phys.ntu.edu.tw [Leung Center for Cosmology and Particle Astrophysics (LeCosPA) and Department of Physics, National Taiwan University, Taipei 10617, Taiwan (China)

2014-04-15

In the context of supersymmetric quantum mechanics, we define a potential through a particular Riccati solution of the composition form (F∘f)(x)=F(f(x)) and obtain a generalized Mielnik construction of one-parameter isospectral potentials when we use the general Riccati solution. Some examples for special cases of F and f are given to illustrate the method. An interesting result is obtained in the case of a parametric double well potential generated by this method, for which it is shown that the parameter of the potential controls the heights of the localization probability in the two wells, and for certain values of the parameter the height of the localization probability can be higher in the smaller well. -- Highlights: •Function-composition generalization of parametric isospectral potentials is presented. •Mielnik one-parameter family of harmonic potentials is obtained as a particular case. •Graphical discussion of regular and singular regions in the parameter space is given.

The composite water and solute transport of barley (Hordeum vulgare) roots: effect of suberized barriers.

Science.gov (United States)

Ranathunge, Kosala; Kim, Yangmin X; Wassmann, Friedrich; Kreszies, Tino; Zeisler, Viktoria; Schreiber, Lukas

2017-03-01

Roots have complex anatomical structures, and certain localized cell layers develop suberized apoplastic barriers. The size and tightness of these barriers depend on the growth conditions and on the age of the root. Such complex anatomical structures result in a composite water and solute transport in roots. Development of apoplastic barriers along barley seminal roots was detected using various staining methods, and the suberin amounts in the apical and basal zones were analysed using gas chromatography-mass spectometry (GC-MS). The hydraulic conductivity of roots ( Lp r ) and of cortical cells ( Lp c ) was measured using root and cell pressure probes. When grown in hydroponics, barley roots did not form an exodermis, even at their basal zones. However, they developed an endodermis. Endodermal Casparian bands first appeared as 'dots' as early as at 20 mm from the apex, whereas a patchy suberin lamellae appeared at 60 mm. The endodermal suberin accounted for the total suberin of the roots. The absolute amount in the basal zone was significantly higher than in the apical zone, which was inversely proportional to the Lp r . Comparison of Lp r and Lp c suggested that cell to cell pathways dominate for water transport in roots. However, the calculation of Lp r from Lp c showed that at least 26 % of water transport occurs through the apoplast. Roots had different solute permeabilities ( P sr ) and reflection coefficients ( σ sr ) for the solutes used. The σ sr was below unity for the solutes, which have virtually zero permeability for semi-permeable membranes. Suberized endodermis significantly reduces Lp r of seminal roots. The water and solute transport across barley roots is composite in nature and they do not behave like ideal osmometers. The composite transport model should be extended by adding components arranged in series (cortex, endodermis) in addition to the currently included components arranged in parallel (apoplastic, cell to cell pathways). © The

Manufacture of nano graphite oxides derived from aqueous glucose solutions and in-situ synthesis of magnetite–graphite oxide composites

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiang, E-mail: liuxiang@ahut.edu.cn; Zhao, Tiantian; Liu, Pengpeng; Cui, Ping, E-mail: cokecp@sohu.com; Hu, Peng

2015-03-01

A “bottom up” approach of manufacturing graphite oxides (GOs) derived from aqueous glucose solutions by virtue of an environmentally-friendly process and the way of in-situ synthesizing magnetite–GOs composites are described in this work in detail. The dehydrations among glucose molecules under hydrothermal condition result in the initial carbon quantum dots and ultimate GOs. The structural information of the GOs is obtained by the infrared, ultraviolet–visible and X-ray photoelectron spectra. The magnetite–GOs composites were obtained by a one-pot method under the same hydrothermal conditions as the one of preparing GOs. The composites perform high activities in catalytic degradation of Rhodamine B in the presence of hydrogen peroxides without extra heating or pH adjusting. Both the GOs and the magnetite–GOs composites are also assured by measurements of transmission electron microscope and X-ray powder diffraction. - Highlights: • Graphite oxides are made from aqueous glucose solutions by hydrothermal reaction. • A way of in-situ synthesizing composites of magnetite–graphite oxides is depicted. • The composites perform high activities in catalytic degradation of Rhodamine B.

Progress of research on the influence of alkaline cation and alkaline solution on bentonite properties

International Nuclear Information System (INIS)

Ye Weimin; Zheng Zhenji; Chen Bao; Chen Yonggui

2011-01-01

Based on the previous laboratory studies and numerical simulation on bentonite in alkaline environments, the effects of alkaline cation and alkaline solution on mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite are emphasized in this paper, temperature, pH values and concentration are discussed as main affecting factors. When bentonite is exposed to alkaline cation or alkaline solution, microstructure of bentonite will be changed due to the dissolution of montmorillonite and the formation of secondary minerals, which results in the decrease of swelling pressure. The amount of the reduction of swelling pressure depends on the concentration of alkaline solution. Temperature, polyvalent cation, salinity and concentration are the main factors affecting hydraulic properties of bentonite under alkaline conditions. Therefore, future research should focus on the mechanism of coupling effects of weak alkaline solutions on the mineral composition, microstructure, swelling capacity and hydraulic properties of bentonite under different temperatures and different pH values. (authors)

40 CFR 63.5795 - How do I know if my reinforced plastic composites production facility is a new affected source or...

Science.gov (United States)

2010-07-01

... for Hazardous Air Pollutants: Reinforced Plastic Composites Production What This Subpart Covers § 63.5795 How do I know if my reinforced plastic composites production facility is a new affected source or an existing affected source? (a) A reinforced plastic composites production facility is a new...

Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

KAUST Repository

Hellstrom, Sondra L.; Jin, Run Zhi; Stoltenberg, Randall M.; Bao, Zhenan

2010-01-01

We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors

Formation of protective composite coatings with the use of solution of TFE telomers

Science.gov (United States)

Mashtalyar, D. V.; Gnedenkov, S. V.; Sinebryukhov, S. L.; Nadaraia, K. V.; Kiryukhin, D. P.; Kushch, P. P.; Kichigina, G. A.; Buznik, V. M.

2017-09-01

This paper presents the method of fabricate and the results of investigation of electrochemical properties and wettability of the composite coatings obtained on the magnesium alloy by plasma electrolytic oxidation (PEO) and the use of the solution of tetrafluoroethylene (TFE) telomers. The fluoropolymer-containing coatings decrease corrosion current density, increase contact angle in comparison with the base PEO-coating and the bare alloy.

Solid-solution-like ZnO/C composites as excellent anode materials for lithium ion batteries

International Nuclear Information System (INIS)

Zhang, Guanhua; Zhang, Hang; Zhang, Xiang; Zeng, Wei; Su, Qingmei; Du, Gaohui; Duan, Huigao

2015-01-01

Exploring advanced anode materials to maximize the capacity of lithium ion batteries has been an active research area for decades. Constructing composites materials has been proved to be one of the most effective methods to achieve higher capacity due to the synergistic effect. In this work, we proposed and demonstrated a concept of solid-solution-like ZnO/C composites to approach the largest possible synergistic effect by introducing the most interfaces and minimizing the pulverization. The solid-solution-like ZnO/C electrode could achieve a high reversible capacity of 813.3 mAh g −1 at a current density of 100 mA g −1 after 100 cycles with a decrease rate of only 0.4% per cycle. Moreover, the discharge capacity still maintained 53.5% of the original value even when the current density increased to 40 times as much as the original, showing a distinguished rate performance. In addition, such solid-solution-like nanofibers can be easily prepared because of their compatibility with the existing industrial PAN-based spinning process. This may pave the way to mass produce lithium ion batteries with significantly enhanced performance using existing low-cost commercial facilities and recipes.

Analytical solution of the thermo-mechanical stresses in a multilayered composite pressure vessel considering the influence of the closed ends

International Nuclear Information System (INIS)

Zhang, Q.; Wang, Z.W.; Tang, C.Y.; Hu, D.P.; Liu, P.Q.; Xia, L.Z.

2012-01-01

Limited work has been reported on determining the thermo-mechanical stresses in a multilayered composite pressure vessel when the influence of its closed ends is considered. In this study, an analytical solution was derived for determining the stress distribution of a multilayered composite pressure vessel subjected to an internal fluid pressure and a thermal load, based on thermo-elasticity theory. In the solution, a pseudo extrusion pressure was proposed to emulate the effect of the closed ends of the pressure vessel. To validate the analytical solution, the stress distribution of the pressure vessel was also computed using finite element (FE) method. It was found that the analytical results were in good agreement with the computational ones, and the effect of thermal load on the stress distribution was discussed in detail. The proposed analytical solution provides an exact means to design multilayered composite pressure vessels. Highlights: ► The thermal-mechanical stress was derived for a multilayered pressure vessel. ► A new pseudo extrusion pressure was proposed to emulate the effect of closed ends. ► The analytical results are in good agreement with the computational ones using FEM. ► The solution provides an exact way to design the multilayered pressure vessel.

Thermogravimetric analysis of phase transitions in cement compositions mixed by sodium silicate solution

Directory of Open Access Journals (Sweden)

Fedosov Sergey Viktorovich

2014-01-01

Full Text Available This paper presents a study of the capability to modify cement by mechanical activation of sodium silicate water solution. Admixtures or blends of binding agents were employed for modifying concrete properties. The liquid glass is applied to protect from chemically or physically unfavorable environmental impacts, such as acidic medium and high temperature. The sodium silicate is a high-capacity setting accelerator. The increasing of the liquid glass proportion in the mix leads to the degradation of the cement paste plasticity and for this reason it is necessary to reduce the amount of liquid glass in the cement paste. The activation of dilute water solution of sodium silicate into rotary pulsating apparatus directly before tempering of the cement paste is an effective way to decrease mass fraction of liquid glass in the cement paste. The results of the combined influence of liquid glass and mechanical activation on physicochemical processes taking place in cement stone are represented in this research. Thermogravimetric analysis was used in order to study cement blends. Thermogravimetric analysis of modified cement stone assays was performed by thermo analyzer SETARAM TGA 92-24. The results of the analysis of phase transition taking place under high-temperature heating of cement stone modified by the mechanical activation of the water solution of the sodium silicate were introduced. Thermograms of cement stone assays were obtained at different hardening age. The comparison of these thermograms allows us to come to a conclusion on the formation and the retention during long time of a more dense structure of the composite matrix mixed by the mechanical activation of sodium silicate water solution. The relation between the concrete composition and its strength properties was stated. Perhaps, the capability of modified concrete to keep calcium ions in sparingly soluble hydrosilicates leads to the increase in its durability and corrosion resistance.

Enhanced adsorptive degradation of Congo red in aqueous solutions using polyaniline/Fe0 composite nanofibers

CSIR Research Space (South Africa)

Bhaumik, M

2015-01-01

Full Text Available In this study, a simple approach was described for the fabrication of composite nanofibers (CNFs) of polyaniline/Fe0 (PANI/Fe0) using a template-free method for the reductive degradation and removal of Congo red (CR) from aqueous solutions. The PANI...

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions.

Science.gov (United States)

Arregui, Maria; Giner, Luis; Ferrari, Marco; Vallés, Marta; Mercadé, Montserrat

2016-11-28

Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility). Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW), coffee (CF), Coca-Cola (CC), red wine (RW), tea (TE) and orange juice (OJ). The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE) were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher's post-hoc test and Pearson's correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17-1.759)); Vertise Flow in CF (∆E = 14.75 (7.91-27.41)), in TE (∆E = 7.27 (2.81-24.81)) and OJ (∆E = 3.17 (0.87-9.92)); Tetric EvoFlow® in CC (∆E = 1.27 (0.45-4.02)); and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23-19.59)). RW caused the most discoloration (∆E = 23.62 (4.93-51.36)). Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19). The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem.

Does mechanical disturbance affect the performance and species composition of submerged macrophyte communities?

Science.gov (United States)

Zhang, Qian; Xu, Ying-Shou; Huang, Lin; Xue, Wei; Sun, Gong-Qi; Zhang, Ming-Xiang; Yu, Fei-Hai

2014-05-01

Submerged macrophyte communities are frequently subjected to disturbance of various frequency and strength. However, there is still little experimental evidence on how mechanical disturbance affects the performance and species composition of such plant communities. In a greenhouse experiment, we constructed wetland communities consisting of five co-occurring clonal submerged macrophyte species (Hydrilla verticillata, Elodea canadensis, Ceratophyllum demersum, Chara fragilis, and Myriophyllum spicatum) and subjected these communities to three mechanical disturbance regimes (no, moderate and strong disturbance). Strong mechanical disturbance greatly decreased overall biomass, number of shoot nodes and total shoot length, and increased species diversity (evenness) of the total community. It also substantially decreased the growth of the most abundant species (H. verticillata), but did not affect growth of the other four species. Our data reveal that strong disturbance can have different effects on different submerged macrophyte species and thus alters the performance and species composition of submerged macrophyte communities.

Adsorption of methyl orange from aqueous solution using chitosan/diatomite composite.

Science.gov (United States)

Zhao, Peng; Zhang, Runhu; Wang, Jianglin

2017-04-01

A novel chitosan/diatomite composite was prepared by a simple mixture in the mass ratio to remove methyl orange (MO) from aqueous media in this study. The composite adsorbent was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy analysis. The parameters to influence the adsorption of MO were studied under such conditions as kinetics, adsorption isotherm, pH effect, and thermodynamics. The results revealed that adsorption of MO was initially rapid and the equilibrium time was reached after 40 min. The optimal value of the pH was 5.0 for better adsorption. The equilibrium data were well fitted to the Langmuir isotherm compared to the Freundlich isotherm, and exhibited the highest capacity and a removal rate of 88.37% under an initial dye concentration of 50 mg/L. The kinetic data were well described by the pseudo-second order model. The thermodynamic calculations revealed that the sorption was viable, spontaneous, and exothermic under the conditions studied. In addition, the chitosan/diatomite composite had good adsorption and desorption performance with respect to reusability after six cycles. These results showed that the chitosan/diatomite could be considered as a potential adsorbent for the removal of MO in aqueous solution.

Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

International Nuclear Information System (INIS)

Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua

2016-01-01

Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

Adsorption of Amido Black 10B from aqueous solutions onto Zr (IV) surface-immobilized cross-linked chitosan/bentonite composite

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lujie; Hu, Pan; Wang, Jing; Huang, Ruihua, E-mail: hrh20022002@163.com

2016-04-30

Graphical abstract: - Highlights: • Zr-CCB was prepared and characterized. • The adsorption of AB10B followed the Langmuir isotherm model. • The pseudo-second-order model described the kinetic behavior. - Abstract: Zr(IV) surface-immobilized cross-linked chitosan/bentonite composite was synthesized by immersing cross-linked chitosan/bentonite composite in zirconium oxychloride solution, and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Scanning electron microscopy techniques. The adsorption of an anionic dye, Amido Black 10B, from aqueous solution by Zr(IV) loaded cross-linked chitosan/bentonite composite was investigated as a function of loading amount of Zr(IV), adsorbent dosage, pH value of initial dye solution, and ionic strength. The removal of Amido Black 10B increased with an increase in loading amount of Zr(IV) and adsorbent dosage, but decreased with an increase in pH or ionic strength. The adsorption of AB10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite was favored at lower pH values and higher temperatures. The Langmuir isotherm model fitted well with the equilibrium adsorption isotherm data and the maximum monolayer adsorption capacity was 418.4 mg/g at natural pH value and 298 K. The pseudo-second-order kinetic model well described the adsorption process of Amido Black 10B onto Zr(IV) loaded cross-linked chitosan/bentonite composite. The possible mechanisms controlling Amido Black 10B adsorption included hydrogen bonding and electrostatic interactions.

Searching for the Optimal Sampling Solution: Variation in Invertebrate Communities, Sample Condition and DNA Quality.

Directory of Open Access Journals (Sweden)

Martin M Gossner

Full Text Available There is a great demand for standardising biodiversity assessments in order to allow optimal comparison across research groups. For invertebrates, pitfall or flight-interception traps are commonly used, but sampling solution differs widely between studies, which could influence the communities collected and affect sample processing (morphological or genetic. We assessed arthropod communities with flight-interception traps using three commonly used sampling solutions across two forest types and two vertical strata. We first considered the effect of sampling solution and its interaction with forest type, vertical stratum, and position of sampling jar at the trap on sample condition and community composition. We found that samples collected in copper sulphate were more mouldy and fragmented relative to other solutions which might impair morphological identification, but condition depended on forest type, trap type and the position of the jar. Community composition, based on order-level identification, did not differ across sampling solutions and only varied with forest type and vertical stratum. Species richness and species-level community composition, however, differed greatly among sampling solutions. Renner solution was highly attractant for beetles and repellent for true bugs. Secondly, we tested whether sampling solution affects subsequent molecular analyses and found that DNA barcoding success was species-specific. Samples from copper sulphate produced the fewest successful DNA sequences for genetic identification, and since DNA yield or quality was not particularly reduced in these samples additional interactions between the solution and DNA must also be occurring. Our results show that the choice of sampling solution should be an important consideration in biodiversity studies. Due to the potential bias towards or against certain species by Ethanol-containing sampling solution we suggest ethylene glycol as a suitable sampling solution when

Acetylene Black/Sulfur Composites Synthesized by a Solution Evaporation Concentration Crystallization Method and Their Electrochemical Properties for Li/S Batteries

Directory of Open Access Journals (Sweden)

Zhigao Yang

2013-07-01

Full Text Available A novel technique to prepare carbon/sulfur composites as cathode materials for Li/S batteries is proposed, which we call the ‘solution evaporation concentration crystallization’ method. Three composites with different S loadings were prepared, subject to two different solvent evaporation rates from acetylene black (AB/sulfur in carbon disulfide solutions. X-ray diffraction, environmental scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller measurements all show that the porous AB structure is well-filled with S. Composites prepared at a lower solvent evaporation rate with 50 wt % S content, had good electrochemical properties, with 1609.67 mAh g−1 after 100 cycles. Composites with better dispersibility at a low solvent evaporation rate can effectively prevent polysulfide from dissolving in the electrolyte, and serve to stabilize the structure of the S cathode during the charge-discharge process.

Investigation into isomolar series of Al(NO3)3, Na3VO4 solution mixture and composition of solid phases

International Nuclear Information System (INIS)

Chernysh, L.F.; Nakhodnova, A.P.; Makarova, R.A.

1979-01-01

Conducted is investigation of properties of isomolar series of aluminium nitrate and sodiUm vanadate solutions at pH of the latter 12.5; 10.0; 7.0 and the temperature of 25 deg C using the methods of pH-metry, conductometry, ''seeming'' volume of precipitations, residual concentration of aluminium and vanadium. It is shown, that the composition property diagram of the system investigated does not reflect the true composition of solid-phase products of the reaction, which depends on the component ratio in solution. Bottom phases of isomolar series are mainly heterogeneous. At the excess of sodium vanadate solution and its high pH values conditions for the basic salt formation are created. At pH of the Na 3 VO 4 solution of 12.5 and 10.0 and Al(NO 3 ) 3 : Na 3 VO 4 ratios 4:6 and 3:7 respectively obtained are the basic aluminium vanadates of the (AlOH) 3 (VO 4 ) 2 x 7.5H 2 O and (AlOH) 2 V 2 O 7 x5H 2 O composition, some of their physicochemical properties being investigated

Possibilities of application of perfect solution model to calculation of equilibrium composition of complex carbonitrides and their solubility in steels

International Nuclear Information System (INIS)

Gol'dshtejn, M.I.; Popov, V.V.; Cheremnykh, V.G.

1980-01-01

Using the Fe-Nb-V-C-N and Fe-Ti-V-C-N systems' low carbon steels, the earlier suggested model of perfect solid solutions has been experimentally researched. Also studied has been the feasibility to calculate the composition of carbonitrides in steels by the derived equations, that comprise, as parameters, products of respective compounds' solubility and coefficients of components interaction in iron-based solid solutions. A conclusion is drawn that perfect solutions models may be used adequately for complex carbonitrides like Nbsub(p)Vsub(1-p)Csub(q)Nsub(1-q) and Tisub(p)Vsub(1-p)Csub(q)Nsub(1-q) during the calculations of their equilibrium composition and solubility in steels

Rapid removal of uranium from aqueous solutions using magnetic Fe3O4@SiO2 composite particles.

Science.gov (United States)

Fan, Fang-Li; Qin, Zhi; Bai, Jing; Rong, Wei-Dong; Fan, Fu-You; Tian, Wei; Wu, Xiao-Lei; Wang, Yang; Zhao, Liang

2012-04-01

Rapid removal of U(VI) from aqueous solutions was investigated using magnetic Fe(3)O(4)@SiO(2) composite particles as the novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, shaking time and initial U(VI) concentrations on uranium sorption efficiency as well as the desorbing of U(VI). The sorption of uranium on Fe(3)O(4)@SiO(2) composite particles was pH-dependent, and the optimal pH was 6.0. In kinetics studies, the sorption equilibrium can be reached within 180 min, and the experimental data were well fitted by the pseudo-second-order model, and the equilibrium sorption capacities calculated by the model were almost the same as those determined by experiments. The Langmuir sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 20-200 mg/L. The maximum uranium sorption capacity onto magnetic Fe(3)O(4)@SiO(2) composite particles was estimated to be about 52 mg/g at 25 °C. The highest values of uranium desorption (98%) was achieved using 0.01 M HCl as the desorbing agent. Fe(3)O(4)@SiO(2) composite particles showed a good selectivity for uranium from aqueous solution with other interfering cation ions. Present study suggested that magnetic Fe(3)O(4)@SiO(2) composite particles can be used as a potential adsorbent for sorption uranium and also provided a simple, fast separation method for removal of heavy metal ion from aqueous solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

Pore solution in alkali-activated slag cement pastes. Relation to the composition and structure of calcium silicate hydrate

International Nuclear Information System (INIS)

Puertas, F.; Fernandez-Jimenez, A.; Blanco-Varela, M.T.

2004-01-01

In this work, the relationship between the composition of pore solution in alkali-activated slag cement (AAS) pastes activated with different alkaline activator, and the composition and structure of the main reaction products, has been studied. Pore solution was extracted from hardened AAS pastes. The analysis of the liquids was performed through different techniques: Na, Mg and Al by atomic absorption (AA), Ca ions by ionic chromatography (IC) and Si by colorimetry; pH was also determined. The solid phases were analysed by XRD, FTIR, solid-state 29 Si and 27 Al NMR and BSE/EDX. The most significant changes in the ionic composition of the pore solution of the AAS pastes activated with waterglass take place between 3 and 24 h of reaction. These changes are due to the decrease of the Na content and mainly to the Si content. Results of 29 Si MAS NMR and FTIR confirm that the activation process takes place with more intensity after 3 h (although at this age, Q 2 units already exist). The pore solution of the AAS pastes activated with NaOH shows a different evolution to this of pastes activated with waterglass. The decrease of Na and Si contents progresses with time. The nature of the alkaline activator influences the structure and composition of the calcium silicate hydrate formed as a consequence of the alkaline activation of the slag. The characteristic of calcium silicate hydrate in AAS pastes activated with waterglass is characterised by a low structural order with a low Ca/Si ratio. Besides, in this paste, Q 3 units are detected. The calcium silicate hydrate formed in the pastes activated with NaOH has a higher structural order (higher crystallinity) and contains more Al in its structure and a higher Ca/Si ratio than those obtained with waterglass

Synthesis and highly visible-induced photocatalytic activity of CNT-CdSe composite for methylene blue solution

Directory of Open Access Journals (Sweden)

Chen Ming-Liang

2011-01-01

Full Text Available Abstract Carbon nanotube-cadmium selenide (CNT-CdSe composite was synthesized by a facile hydrothermal method derived from multi-walled carbon nanotubes as a stating material. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy (TEM, and UV-vis diffuse reflectance spectrophotometer. The as-synthesized CNT-CdSe composite efficiently catalyzed the photodegradation of methylene blue in aqueous solutions under visible-light irradiation, exhibiting higher photocatalytic activity.

Herbivory of an invasive slug is affected by earthworms and the composition of plant communities.

Science.gov (United States)

Zaller, Johann G; Parth, Myriam; Szunyogh, Ilona; Semmelrock, Ines; Sochurek, Susanne; Pinheiro, Marcia; Frank, Thomas; Drapela, Thomas

2013-05-13

Biodiversity loss and species invasions are among the most important human-induced global changes. Moreover, these two processes are interlinked as ecosystem invasibility is considered to increase with decreasing biodiversity. In temperate grasslands, earthworms serve as important ecosystem engineers making up the majority of soil faunal biomass. Herbivore behaviour has been shown to be affected by earthworms, however it is unclear whether these effects differ with the composition of plant communities. To test this we conducted a mesocosm experiment where we added earthworms (Annelida: Lumbricidae) to planted grassland communities with different plant species composition (3 vs. 12 plant spp.). Plant communities had equal plant densities and ratios of the functional groups grasses, non-leguminous forbs and legumes. Later, Arion vulgaris slugs (formerly known as A. lusitanicus; Gastropoda: Arionidae) were added and allowed to freely choose among the available plant species. This slug species is listed among the 100 worst alien species in Europe. We hypothesized that (i) the food choice of slugs would be altered by earthworms' specific effects on the growth and nutrient content of plant species, (ii) slug herbivory will be less affected by earthworms in plant communities containing more plant species than in those with fewer plant species because of a more readily utilization of plant resources making the impacts of earthworms less pronounced. Slug herbivory was significantly affected by both earthworms and plant species composition. Slugs damaged 60% less leaves when earthworms were present, regardless of the species composition of the plant communities. Percent leaf area consumed by slugs was 40% lower in communities containing 12 plant species; in communities containing only three species earthworms increased slug leaf area consumption. Grasses were generally avoided by slugs. Leaf length and number of tillers was increased in mesocosms containing more plant

Measurement of isotopic composition of lanthanides in reprocessing process solutions by high-performance liquid chromatography with inductively coupled plasma mass spectrometry (HPLC/ICP-MS)

International Nuclear Information System (INIS)

Okano, Masanori; Jitsukata, Shu; Kuno, Takehiko; Yamada, Keiji

2011-01-01

Isotopic compositions of fission products in process solutions and wastes in a reprocessing plant are valuable to proceed safety study of the solutions and research/development concerning treatment/disposal of the wastes. The amount of neodymium-148 is a reliable indication to evaluate irradiation history. The isotopic compositions of samarium and gadolinium in high radioactive wastes are referred to as essential data to evaluate environmental impact in geological repositories. However, pretreatment of analysis must be done with complicated chemical separation such as solvent extraction and ion exchange. The actual measurement data of isotopic compositions of lanthanides comparable to the one of actinides in spent fuel reprocessing process has not been obtained enough. Rapid and high sensitive analytical technique based on high-performance liquid chromatography (HPLC) with an inductively coupled plasma mass spectrometry (ICP-MS) has been developed for the measurement of isotopic compositions of lanthanides in spent fuel reprocessing solutions. HPLC/ICP-MS measurement system was customized for a glove-box to be applied to the radioactive solutions. The cation exchange chromatographic columns (Shim-pack IC-C1) and injection valve (20μL) were located inside of the glove-box except the chromatographic pump. The elements of lanthanide group were separated by a gradient program of HPLC with α-hydroxyisobutyric acid. Isotopic compositions of lanthanides in eluate was sequentially analyzed by a quadruple ICP-MS. Optimization of parameter of HPLC and ICP-MS measurement system was examined with standard solutions containing 14 lanthanide elements. The elements of lanthanides were separated by HPLC and detected by ICP-MS within 25 minutes. The detection limits of Nd-146, Sm-147 and Gd-157 were 0.37 μg L -1 , 0.69 μg L -1 and 0.47 μg L -1 , respectively. The analytical precision of the above three isotopes was better than 10% for standard solutions of 100 μg L -1 with

Effect of liquid oil additive on lithium-ion battery ceramic composite separator prepared with an aqueous coating solution

Energy Technology Data Exchange (ETDEWEB)

Kim, Sang Woo [Division of Advanced Materials Engineering, Kongju National University, 1223–24, Cheonan-daero, Cheonan, Chungnam, 31080 (Korea, Republic of); Ryou, Myung-Hyun [Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 (Korea, Republic of); Lee, Yong Min, E-mail: yongmin.lee@hanbat.ac.kr [Department of Chemical & Biological Engineering, Hanbat National University, 125, Dongseodaero, Yuseong-gu, Daejeon, 34158 (Korea, Republic of); Cho, Kuk Young, E-mail: kycho@hanyang.ac.kr [Department of Materials Science and Chemical Engineering, Hanyang University, 55, Hanyangdaehak-ro, Sangrok-gu, Ansan, Gyeonggi-do, 15588 (Korea, Republic of)

2016-08-05

Ceramic composite separators (CCSs) play a critical role in ensuring safety for lithium-ion batteries (LIBs), especially for mid- and large-sized devices. However, production of CCSs using organic solvents has some cost and environmental concerns. An aqueous process for fabricating CCSs is attractive because of its cost-effectiveness and environmental-friendliness because organic solvents are not used. The success of an aqueous coating system for LIBs is dependent upon minimizing moisture content, as moisture has a negatively impact on LIB performance. In this study, CCSs were fabricated using an aqueous coating solution containing Al{sub 2}O{sub 3} and an acrylic binder. Compared with polyethylene (PE) separators, CCSs coated with an aqueous coating solution showed improved thermal stability, electrolyte uptake, puncture strength, ionic conductivity, and rate capability. In addition, our new approach of introducing a small amount of an oily liquid to the aqueous coating solution reduced the water adsorption by 11.7% compared with coatings that do not contain the oily liquid additive. - Highlights: • Ceramic composite separator is fabricated using aqueous coating process. • Coated separator showed enhanced mechanical and thermal stability. • Liquid oil additive in coating solution reduce moisture reabsorption of separator. • Oil additive in aqueous coating solution does not deteriorate LIB performance.

Preparation of Organic/Inorganic Siloxane Composite Membranes and Concentration of n-butanol from ABE Solution by Pervaporation

Energy Technology Data Exchange (ETDEWEB)

Jee, Ki Yong; Lee, Yong Taek [Kyung Hee University, Yongin (Korea, Republic of)

2013-10-15

In this paper, polymer composite membranes and ceramic composite membranes were prepared in order to compare differences in pervaporation performances relative to the support layers. PVDF was used for the polymer support layers, and a-Al{sub 2}O{sub 3} was used for the ceramic support layers. For active layer was coated for PDMS, which is a rubbery polymer. The characterization of membranes were analysed by SEM, contact angle, and XPS. We studied performances relative to the composite membrane support layers in the ABE mixture solutions. The results of the pervaporation, the flux of the ceramic composite membrane was shown to be 250.87 g/m{sup 2}h, which was higher than that of polymer composite membranes, at 195.64 g/m{sup 2}h. However, it was determined that the separation factor of the polymer composite membranes was 31.98 which were higher than that of the ceramic composite membranes, at 20.66.

Analytical Analysis and Field Test Investigation of Consolidation for CCSG Pile Composite Foundation in Soft Clay

Directory of Open Access Journals (Sweden)

Jin Yu

2013-01-01

Full Text Available Low-grade concrete-cored sand-gravel (CCSG pile composite foundation is a new kind of composite foundation for thick and soft clay ground treatment. An analytical solution was derived for calculating the consolidation process of this composite foundation by considering coefficients of horizontal permeability in smear zone, the radial flow within the sand-gravel shell, and the impervious property of concrete-cored pile. The results show that Terzaghi’s one-dimensional consolidation solution and the consolidation analytical solution of ordinary composite foundation were special cases of this solution. Curves of the average consolidation degree of the composite foundation under various nondimensional parameters were observed using the program based on the theoretical formula. Meanwhile, a series of in situ measurements including the settlement of pile and soil, the pore water pressure, and the total stress under embankment load were obtained on the CCSG pile composite foundation on a section of Zhenjiang-Liyang highway. The analyzed results show that the new style composite foundation patent technology has many advantages such as small differential postconstruction settlement (differential is not good, small is, reliable quality, high bearing capacity, and stability. And the consolidation of composite foundation is largely affected by the nondimensional parameters. The analytical solution is finally verified with the actual measurement data.

Factors affecting marginal integrity of class II bulk-fill composite resin restorations

Science.gov (United States)

Savadi Oskoee, Siavash; Bahari, Mahmoud; Jafari Navimipour, Elmira; Ajami, Amir Ahmad; Ghiasvand, Negar; Savadi Oskoee, Ayda

2017-01-01

Background. Bulk-fill composite resins are a new type of resin-based composite resins, claimed to have the capacity to be placed in thick layers, up to 4 mm. This study was carried out to evaluate factors affecting gap formation in Cl II cavities restored using the bulk-fill technique. Methods. A total of 60 third molars were used in this study. Two Cl II cavities were prepared in each tooth, one on the mesial aspect 1 mm coronal to the CEJ and one on the distal aspect 1 mm apical to the CEJ. The teeth were divided into 4 groups: A: The cavities were restored using the bulk-fill technique with Filtek P90 composite resin and its adhesive system and light-cured with quartz tungsten halogen (QTH) light-curing unit. B: The cavities were restored similar to that in group A but light-cured with an LED light-curing unit. C: The cavities were restored using the bulk-fill technique with X-tra Fil composite resin and Clearfil SE Bond adhesive system and light-cured with a QTH curing unit. D: The cavities were restored similar to that in group C but light-cured with an LED light-curing unit. The gaps were examined under a stereomicroscope at ×60. Data were analyzed with General Linear Model test. In cases of statistical significance (Pcomposite resin type and margin location (Pcomposite resin type were not significant; however, the cumulative effect of composite rein type*gingival margin was significant (P=0.04) Conclusion. X-tra Fil composite exhibited smaller gaps compared with Filtek P90 composite with both light-curing units. Both composite resins exhibited smaller gaps at enamel margins. PMID:28748051

Optimum culture medium composition for lipopeptide production by ...

Indian Academy of Sciences (India)

the media compositions so as to enhance the productivity of lipopeptide. The optimized media by ... provides greater insight in studying the impact of potential variables affecting the ... ing more flexible solutions than the classical optimization techniques. To the ... Hence, in this work, it is proposed to optimize the lipopeptide ...

Dependence of osmotic pressure on solution properties

International Nuclear Information System (INIS)

Fritz, S.J.

1978-01-01

Hydrostatic pressure, temperature, salt concentration, and the chemical composition of the salt are parameters affecting solution properties. Pressure and temperature have little effect on osmosis, but osmotic pressure variations due to type of dissolved salt may be significant, especially at high concentrations. For a given salt solution, concentration variations cause large differences in osmotic pressure. A representative difference in concentration across a clay layer in a relatively shallow groundwater system might be 100 to 1,000 ppm. When expressed as ppm NaCl, this difference could cause a head difference of 0.8 to 8 meters of water if one of the rock bodies were closed to fluid escape

Magnetoimpedance of cobalt-based amorphous ribbons/polymer composites

Energy Technology Data Exchange (ETDEWEB)

Semirov, A.V., E-mail: semirov@mail.ru [Irkutsk State University, Irkutsk (Russian Federation); Derevyanko, M.S.; Bukreev, D.A.; Moiseev, A.A.; Kudryavtsev, V.O. [Irkutsk State University, Irkutsk (Russian Federation); Safronov, A.P. [Ural Federal University, Yekaterinburg (Russian Federation)

2016-10-01

The combined influence of the temperature, the elastic tensile stress and the external magnetic field on the total impedance and impedance components were studied for rapidly quenched amorphous Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16} ribbons. Both as-cast amorphous ribbons and Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16}/polymer amorphous ribbon based composites were considered. Following polymer coverings were studied: modified rubber solution in o-xylene, solution of butyl methacrylate and methacrylic acid copolymer in isopropanol and solution of polymethylphenylsiloxane resin in toluene. All selected composites showed very good adhesion of the coverings and allowed to provide temperature measurements from 163 K up to 383 K under the applied deforming tensile force up to 30 N. The dependence of the modulus of the impedance and its components on the external magnetic field was influenced by the elastic tensile stresses and was affected by the temperature of the samples. It was shown that maximal sensitivity of the impedance and its components to the external magnetic field was observed at minimal temperature and maximal deforming force depended on the frequency of an alternating current. - Highlights: • Impedance and its components of amorphous Co{sub 75}Fe{sub 5}Si{sub 4}B{sub 16} ribbons were studied. • MI sensitivity to the magnetic field depends on a temperature and a deforming force. • Polymer covering can affect the functional properties of the composite.

Room-temperature solution-processed and metal oxide-free nano-composite for the flexible transparent bottom electrode of perovskite solar cells

Science.gov (United States)

Lu, Haifei; Sun, Jingsong; Zhang, Hong; Lu, Shunmian; Choy, Wallace C. H.

2016-03-01

The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self-assembly approach under ambient atmosphere, which can effectively prevent the penetration of liquid or gaseous halides and their corrosion against the silver nano-network underneath. Importantly, we simultaneously achieve good work function alignment and surface wetting properties for a practical bottom electrode by controlling the degree of reduction of GO flakes. Finally, flexible PVSC adopting the room-temperature and solution-processed nano-composite as the flexible transparent bottom electrode has been demonstrated on a polyethylene terephthalate (PET) substrate. As a consequence, the demonstration of our room-temperature solution-processed and metal oxide-free flexible transparent bottom electrode will contribute to the emerging large-area flexible PVSC technologies.The exploration of low-temperature and solution-processed charge transporting and collecting layers can promote the development of low-cost and large-scale perovskite solar cells (PVSCs) through an all solution process. Here, we propose a room-temperature solution-processed and metal oxide-free nano-composite composed of a silver nano-network and graphene oxide (GO) flawless film for the transparent bottom electrode of a PVSC. Our experimental results show that the amount of GO flakes play a critical role in forming the flawless anti-corrosive barrier in the silver nano-network through a self

The influence of solution composition and grain boundaries on the replacement of calcite by dolomite

Science.gov (United States)

Moraila Martinez, Teresita de Jesus; Putnis, Christine V.; Putnis, Andrew

2016-04-01

Dolomite formation is a mineral replacement reaction that affects extensive rock volumes and comprises a large fraction of oil and gas reservoirs [1,2]. The most accepted hypothesis is the 'dolomitization' of limestone by Mg-rich fluids [3]. The objective of this research is to study the replacement mechanism of calcite by dolomite, the role of grain boundaries, highlighted by Etschmann et al. (2014), and the possible influence of solutions in dolomite formation under the presence of ions that are normally in crustal aqueous fluids. To accomplish this purpose, we performed hydrothermal experiments using Carrara marble cubes of ~1.5 mm size and 7-9 mg weight as starting material, reacted with 1M (Mg,Ca)Cl2 aqueous solutions, with Mg/Ca ratios of 3 and 5 at 200°C, for different reaction times. Additional experiments were performed adding 1mM of Na2SO4, NaCl or NaF to the previous solutions. After the reaction, the product phases were identified using Raman spectroscopy, X-Ray powder diffraction (XRD), electron microprobe analysis (EMPA), and the textural evolution was studied by scanning electron microscopy (SEM). Samples reacted with aqueous solutions resulted in the replacements of the calcite rock into magnesite and dolomite. The amount and type of reaction strongly depends on the Mg/Ca ratio. Samples reacted with a Mg/Ca ratio of 5 resulted in an almost complete replacement reaction and more favorable for magnesite formation than for dolomite. When the Mg/Ca ratio was 3 dolomite formed but the replacement was located in the core of the sample. We show that grain boundaries are very important for the infiltration of solution and the progress of a replacement reaction, acting as fluid pathways. Solution composition controls the nature of the replacement product. Acknowledgment: This work is funded within a Marie Curie EU Initial Training Network- CO2-React. 1. Etschmann B., Brugger J., Pearce M.A., Ta C., Brautigan D., Jung M., Pring A. (2014). Grain boundaries as

Variability in the contents of pork meat nutrients and how it may affect food composition databases.

Science.gov (United States)

Reig, Milagro; Aristoy, M-Concepción; Toldrá, Fidel

2013-10-01

Pork meat is generally recognised as a food with relevant nutritional properties because of its content in high biological value proteins, group B vitamins, minerals especially heme iron, trace elements and other bioactive compounds. But pork meat also contributes to the intake of fat, saturated fatty acids, cholesterol, and other substances that, in inappropriate amounts, may result in negative physiologically effects. However, there are relevant factors affecting the content of many of these substances and somehow such variability should be taken into consideration. So, genetics, age and even type of muscle have a relevant influence on the amount of fat and the contents in heme iron. Also the composition in fatty acids of triacylglycerols is very sensitive to the contents of cereals in the feed; for instance, polyunsaturated fatty acids may range from 10% to 22% in pork meat. The content of other nutrients, like vitamins E and A, are also depending on the type of feed. Some bioactive substances like coenzyme Q10, taurine, glutamine, creatine, creatinine, carnosine and anserine show a large dependence on the type of muscle. This manuscript describes the main factors affecting the composition of pork meat nutrients and how these changes may affect the general food composition databases. Copyright © 2012 Elsevier Ltd. All rights reserved.

Six-month color change and water sorption of 9 new-generation flowable composites in 6 staining solutions

Directory of Open Access Journals (Sweden)

Maria ARREGUI

Full Text Available Abstract Color match and water sorption are two factors that affect restorative materials. Discoloration is essential in the lifespan of restorations. The aim of this study was to evaluate color change and water sorption of nine flowable composites at multiple time points over 6 months. 60 samples of each composite were divided into two groups (Color Change and Water Sorption/Solubility. Each Color Change group was divided into six subgroups, which were immersed in distilled water (DW, coffee (CF, Coca-Cola (CC, red wine (RW, tea (TE and orange juice (OJ. The color was measured at the baseline, 1, 2, 3 and 4 weeks, and 3 and 6 months and color change values (ΔE were calculated. Each Water Sorption [WS]/Solubility [WL] group was tested according to ISO 4049:2009. The data were evaluated using two-way ANOVA, Fisher’s post-hoc test and Pearson’s correlation test. The composite with the lowest ΔE differed for each solution: Filtek™ Bulk Fill in DW (∆E = 0.73 (0.17–1.759; Vertise Flow in CF (∆E = 14.75 (7.91–27.41, in TE (∆E = 7.27 (2.81–24.81 and OJ (∆E = 3.17 (0.87–9.92; Tetric EvoFlow® in CC (∆E = 1.27 (0.45–4.02; and Filtek™ Supreme XTE in RW (∆E = 8.88 (5.23–19.59. RW caused the most discoloration (∆E = 23.62 (4.93–51.36. Vertise Flow showed the highest water sorption (WS = 69.10 ± 7.19. The Pearson test showed statistically significant positive correlations between water sorption and solubility and between water sorption and ∆E; the positive solubility-∆E correlation was not statistically significant. The findings suggest that water sorption is one factor associated with the ability of composites to discolor; however, discoloration is a multifactorial problem.

Polymer solution phase separation: Microgravity simulation

Science.gov (United States)

Cerny, Lawrence C.; Sutter, James K.

1989-01-01

In many multicomponent systems, a transition from a single phase of uniform composition to a multiphase state with separated regions of different composition can be induced by changes in temperature and shear. The density difference between the phase and thermal and/or shear gradients within the system results in buoyancy driven convection. These differences affect kinetics of the phase separation if the system has a sufficiently low viscosity. This investigation presents more preliminary developments of a theoretical model in order to describe effects of the buoyancy driven convection in phase separation kinetics. Polymer solutions were employed as model systems because of the ease with which density differences can be systematically varied and because of the importance of phase separation in the processing and properties of polymeric materials. The results indicate that the kinetics of the phase separation can be performed viscometrically using laser light scattering as a principle means of following the process quantitatively. Isopycnic polymer solutions were used to determine the viscosity and density difference limits for polymer phase separation.

Theoretical prediction of morphotropic compositions in Na1/2Bi1/2TiO3-based solid solutions from transition pressures

Science.gov (United States)

Gröting, Melanie; Albe, Karsten

2014-02-01

In this article we present a method based on ab initio calculations to predict compositions at morphotropic phase boundaries in lead-free perovskite solid solutions. This method utilizes the concept of flat free energy surfaces and involves the monitoring of pressure-induced phase transitions as a function of composition. As model systems, solid solutions of Na1/2Bi1/2TiO3 with the alkali substituted Li1/2Bi1/2TiO3 and K1/2Bi1/2TiO3 and the alkaline earth substituted CaTiO3 and BaTiO3 are chosen. The morphotropic compositions are identified by determining the composition at which the phase transition pressure equals zero. In addition, we discuss the different effects of hydrostatic pressure (compression and tension) and chemical substitution on the antiphase tilts about the [111] axis (a-a-a-) present in pure Na1/2Bi1/2TiO3 and how they develop in the two solid solutions Na1/2Bi1/2TiO3-CaTiO3 and Na1/2Bi1/2TiO3-BaTiO3. Finally, we discuss the advantages and shortcomings of this simple computational approach.

Inhaled corticosteroid metered-dose inhalers: how do variations in technique for solutions versus suspensions affect drug distribution?

Science.gov (United States)

Robinson, Christie A; Tsourounis, Candy

2013-03-01

To assess the literature that evaluates how variations in metered-dose inhaler (MDI) technique affect lung distribution for inhaled corticosteroids (ICSs) formulated as MDI suspensions and solutions. PubMed (up to November 2012) and Cochrane Library (up to November 2012) were searched using the terms metered-dose inhalers, HFA 134a, Asthma/*drug therapy, and inhaled corticosteroids. In addition, reference citations from publications identified were reviewed. All articles in English from the data sources that assessed MDI technique comparing total lung distribution (TLD) of MDI solutions or suspensions formulated with ICSs were included in the review. Five relevant studies were identified. Five controlled studies compared how variations in MDI technique affect TLD for ICS MDI solutions with suspensions. MDI solutions resulted in greater TLD compared with larger particle MDI suspensions. Delayed or early inspiration upon device actuation of MDI solutions resulted in less TLD than coordinated actuation, but with a 3- to 4-times greater TLD than MDI suspensions inhaled using a standard technique. A sixth study evaluated inspiratory flow rates (IFR) for small, medium, and large particles. Rapid and slow IFRs resulted in similar TLD for small particles, while far fewer particles reached the airways with medium and large particles at rapid, rather than slow, IFRs. Based on the literature evaluated, standard MDI technique should be used for ICS suspensions. ICS MDI solutions can provide a higher average TLD than larger-particle ICS suspensions using standard technique, discoordinated inspiration and medication actuation timing, or rapid and slow IFRs. ICS MDI solutions allow for a more forgiving technique, which makes them uniquely suitable options for patients with asthma who have difficultly with MDI technique.

Antibiotic treatment affects intestinal permeability and gut microbial composition in Wistar rats dependent on antibiotic class

DEFF Research Database (Denmark)

Tulstrup, Monica Vera-Lise; Christensen, Ellen Gerd; Carvalho, Vera

2015-01-01

Antibiotics are frequently administered orally to treat bacterial infections not necessarily related to the gastrointestinal system. This has adverse effects on the commensal gut microbial community, by disrupting the intricate balance between specific bacterial groups within this ecosystem...... potentially leading to dysbiosis. We hypothesized that modulation of community composition and function induced by antibiotics affects intestinal integrity depending on the antibiotic administered. To address this a total of 60 Wistar rats (n=12 per group) were dosed by oral gavage with either amoxicillin...... (AMX), cefataxime (CTX), vancomycin (VAN), metronidazole (MTZ), or water (CON) daily for 10-11 days. Bacterial composition, alpha diversity and cecum short chain fatty acid levels were significantly affected by AMX, CTX and VAN, and varied among antibiotic treatments. A general decrease in diversity...

Solution processable RGO-CdZnS composite for solar light responsive photocatalytic degradation of 4-Nitrophenol

Science.gov (United States)

Ibrahim, Sk; Chakraborty, Koushik; Pal, Tanusri; Ghosh, Surajit

2017-05-01

We report the one pot single step synthesis and characterization of solution processable reduced graphene oxide (RGO) - cadmium zinc sulfide (CdZnS) nanocomposite materials. The composite was characterized structurally and morphologically by XRD and TEM studies. The reduction of GO in RGO-CdZnS composite, was confirmed by XPS and Raman spectroscopy. The photocatalytic activity of the RGO-CdZnS composite was investigated towards the degradation of 4-Nitrophenol. A notable increase of photocatalytic efficiency of RGO-CdZnS compare to controlled CdZnS was observed. Here RGO plays a crucial role to efficient photo induced charge separation from the CdZnS, and decreases the electron-hole recombination probability and subsequently enhanced the photocatalytic activity of the RGO-CdZnS composite material under simulated solar light irradiation. This work highlights the potential application of RGO-based materials in the field of photocatalytic degradation of organic water pollutant.

The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein-Lecithin Composite Colloidal Nanoparticles.

Science.gov (United States)

Dai, Lei; Sun, Cuixia; Wang, Di; Gao, Yanxiang

2016-01-01

Lecithin, a naturally small molecular surfactant, which is widely used in the food industry, can delay aging, enhance memory, prevent and treat diabetes. The interaction between zein and soy lecithin with different mass ratios (20:1, 10:1, 5:1, 3:1, 2:1, 1:1 and 1:2) in ethanol-water solution and characterisation of zein and lecithin composite colloidal nanoparticles prepared by antisolvent co-precipitation method were investigated. The mean size of zein-lecithin composite colloidal nanoparticles was firstly increased with the rise of lecithin concentration and then siginificantly decreased. The nanoparticles at the zein to lecithin mass ratio of 5:1 had the largest particle size (263 nm), indicating that zein and lecithin formed composite colloidal nanoparticles, which might aggregate due to the enhanced interaction at a higher proportion of lecithin. Continuing to increase lecithin concentration, the zein-lecithin nanoparticles possibly formed a reverse micelle-like or a vesicle-like structure with zein in the core, which prevented the formation of nanoparticle aggregates and decreased the size of composite nanoparticles. The presence of lecithin significantly reduced the ζ-potential of zein-lecithin composite colloidal nanoparticles. The interaction between zein and lecithin enhanced the intensity of the fluorescence emission of zein in ethanol-water solution. The secondary structure of zein was also changed by the addition of lecithin. Differential scanning calorimetry thermograms revealed that the thermal stability of zein-lecithin nanoparticles was enhanced with the rise of lecithin level. The composite nanoparticles were relatively stable to elevated ionic strengths. Possible interaction mechanism between zein and lecithin was proposed. These findings would help further understand the theory of the interaction between the alcohol soluble protein and the natural small molecular surfactant. The composite colloidal nanoparticles formed in this study can

Synthesis of titanium oxide nanoparticles using DNA-complex as template for solution-processable hybrid dielectric composites

Energy Technology Data Exchange (ETDEWEB)

Ramos, J.C. [Center for Sustainable Materials Chemistry, 153 Gilbert Hall, Oregon State University, Corvallis, OR (United States); Mejia, I.; Murphy, J.; Quevedo, M. [Department of Materials Science and Engineering, University of Texas at Dallas, Dallas, TX (United States); Garcia, P.; Martinez, C.A. [Engineering and Technology Institute, Autonomous University of Ciudad Juarez, Ciudad Juarez, Chihuahua (Mexico)

2015-09-15

Highlights: • We developed a synthesis method to produce TiO{sub 2} nanoparticles using a DNA complex. • The nanoparticles were anatase phase (~6 nm diameter), and stable in alcohols. • Composites showed a k of 13.4, 4.6 times larger than the k of polycarbonate. • Maximum processing temperature was 90 °C. • Low temperature enables their use in low-voltage, low-cost, flexible electronics. - Abstract: We report the synthesis of TiO{sub 2} nanoparticles prepared by the hydrolysis of titanium isopropoxide (TTIP) in the presence of a DNA complex for solution processable dielectric composites. The nanoparticles were incorporated as fillers in polycarbonate at low concentrations (1.5, 5 and 7 wt%) to produce hybrid dielectric films with dielectric constant higher than thermally grown silicon oxide. It was found that the DNA complex plays an important role as capping agent in the formation and suspension stability of nanocrystalline anatase phase TiO{sub 2} at room temperature with uniform size (∼6 nm) and narrow distribution. The effective dielectric constant of spin-cast polycarbonate thin-films increased from 2.84 to 13.43 with the incorporation of TiO{sub 2} nanoparticles into the polymer host. These composites can be solution processed with a maximum temperature of 90 °C and could be potential candidates for its application in low-cost macro-electronics.

Differences in Cellulosic Supramolecular Structure of Compositionally Similar Rice Straw Affect Biomass Metabolism by Paddy Soil Microbiota.

Directory of Open Access Journals (Sweden)

Tatsuki Ogura

Full Text Available Because they are strong and stable, lignocellulosic supramolecular structures in plant cell walls are resistant to decomposition. However, they can be degraded and recycled by soil microbiota. Little is known about the biomass degradation profiles of complex microbiota based on differences in cellulosic supramolecular structures without compositional variations. Here, we characterized and evaluated the cellulosic supramolecular structures and composition of rice straw biomass processed under different milling conditions. We used a range of techniques including solid- and solution-state nuclear magnetic resonance (NMR and Fourier transform infrared spectroscopy followed by thermodynamic and microbial degradability characterization using thermogravimetric analysis, solution-state NMR, and denaturing gradient gel electrophoresis. These measured data were further analyzed using an "ECOMICS" web-based toolkit. From the results, we found that physical pretreatment of rice straw alters the lignocellulosic supramolecular structure by cleaving significant molecular lignocellulose bonds. The transformation from crystalline to amorphous cellulose shifted the thermal degradation profiles to lower temperatures. In addition, pretreated rice straw samples developed different microbiota profiles with different metabolic dynamics during the biomass degradation process. This is the first report to comprehensively characterize the structure, composition, and thermal degradation and microbiota profiles using the ECOMICS toolkit. By revealing differences between lignocellulosic supramolecular structures of biomass processed under different milling conditions, our analysis revealed how the characteristic compositions of microbiota profiles develop in addition to their metabolic profiles and dynamics during biomass degradation.

The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein?Lecithin Composite Colloidal Nanoparticles

OpenAIRE

Dai, Lei; Sun, Cuixia; Wang, Di; Gao, Yanxiang

2016-01-01

Lecithin, a naturally small molecular surfactant, which is widely used in the food industry, can delay aging, enhance memory, prevent and treat diabetes. The interaction between zein and soy lecithin with different mass ratios (20:1, 10:1, 5:1, 3:1, 2:1, 1:1 and 1:2) in ethanol-water solution and characterisation of zein and lecithin composite colloidal nanoparticles prepared by antisolvent co-precipitation method were investigated. The mean size of zein-lecithin composite colloidal nanoparti...

Corrosion Behaviour of Heat - Treated Al-6063/ SiCp Composites Immersed in 5 wt% NaCl Solution

Directory of Open Access Journals (Sweden)

Kenneth ALANEME

2011-06-01

Full Text Available The influence of SiC volume percent and temper conditions (namely, as-cast, solutionized, and artificial age hardening at 180°C and 195°C on the corrosion behaviour of Al (6063 composites and its monolithic alloy immersed in 5wt% NaCl solution has been investigated. Al (6063 - SiC particulate composites containing 6, 12 and 15 volume percent SiC were produced by premixing the SiC particles with borax additive and then adopting two step stir casting. Mass loss and corrosion rate measurements were utilized as criteria for evaluating the corrosion behaviour of the composites. The results show that the corrosion susceptibility of the Al (6063 - SiCp composites was higher than that of the monolithic alloy, and for most cases the corrosion rate of the composites increased with increase in volume percent of SiC. However, it was discovered that the nature of the passive films formed on the composites was sufficiently stable to reduce significantly the corrosion rate of the composites after 13days of immersion. This trend was observed to be consistent for all heat-treatment conditions utilized.

Preparation of polyester /Calcium sulfate/ composites using radiation

International Nuclear Information System (INIS)

Ajji, Z.

2004-01-01

Different composites have been prepared using various doses of gamma radiation. Two polyesters, Super Mastics and General, and calcium sulfate or natural gypsum have been used for preparing the composites. Some physical properties of the composites and the influence of Gamma rays on it has been studied as: compression, hardness, thermal decomposition temperature in nitrogen or oxygen, and change in weight in aqua solutions with different pH. Our results show that the glass transition temperature increases by increasing the absorbed dose up to a plateau. Further, the composites show a good thermal stability, and the absorbed dose does not affect the thermal decomposition temperature or the oxidation induction time for the prepared composites. Compression strength of the prepared composites decreases by increasing the filler ratios, and the absorbed does not seem to influence this property significantly. (author)

Preparation of polyester /Calcium sulfate/ composites using radiation

International Nuclear Information System (INIS)

Ajji, Z.

2003-04-01

Different composites have been prepared using various doses of gamma radiation. Two polyesters, Super Mastics and General, and calcium sulfate or natural gypsum have been used for preparing the composites. Some physical properties of the composites and the influence of Gamma rays on it has been studied as: compression, hardness, thermal decomposition temperature in nitrogen or oxygen, and change in weight in aqua solutions with different pH. Our results show that the glass transition temperature increases by increasing the absorbed dose up to a plateau. Further, the composites show a good thermal stability, and the absorbed dose does not affect the thermal decomposition temperature or the oxidation induction time for the prepared composites. Compression strength of the prepared composites decreases by increasing the filler ratios, and the absorbed does not seem to influence this property significantly. (author)

Adsorption of Pb(II) from aqueous solution using a magnetic chitosan/graphene oxide composite and its toxicity studies.

Science.gov (United States)

Melvin Samuel, S; Shah, Sk Sheriff; Bhattacharya, Jayanta; Subramaniam, Kalidass; Pradeep Singh, N D

2018-05-02

This study involves the adsorption of lead using magnetic chitosan/graphene oxide (MCGO) composite material in batch mode. The MCGO composite material was synthesized via modified Hummers method. The MCGO composite material was characterized by powder x-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Tunnelling electron microscopy (TEM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET) and UV-vis diffusive reflectance spectra. The adsorption mechanism of MCGO composite material was well described by Langmuir isotherm and pseudo second order kinetic model, with a high regression coefficient (composite material was applied for the removal of lead metal from aqueous solution. We have also evaluated toxicity of synthesized MCGO composite material by examining on A549 cells. The results have shown that MCGO material showed viable cell percentage of 53.7% at 50 μg and 44.8% at 100 μg. Copyright © 2017. Published by Elsevier B.V.

Corrosion performance of SiCsubp/6061 Al metal matrix composites in sodium chloride solution

International Nuclear Information System (INIS)

Mohmad Soib bin Selamat

1995-01-01

The corrosion performance of silicon carbide particle/aluminium metal matrix composites (SiCsubp/Al) were studied in sodium chloride solution by means of electrochemical, microscopic, gravimetric and analytical techniques. The materials under investigation were compocasting processed 6061 Al reinforced with increasing amounts of SiC particles. Potentiostatic polarization tests were done in 0.1M NaCl solutions that were aerated or deaerated to observe overall corrosion behaviour. It was seen that the corrosion potentials did not vary greatly in relation to the amounts of SiCsubp reinforcement. Corrosion tests showed that the degree of corrosion increased with increasing SiCsubp content. SEM analysis technique was used to study the corroded samples and the pitting morphology. By TEM, no intermetallic layer was found at SiC/Al interface. A model for pitting process was proposed

Influence of staining solutions and whitening procedures on discoloration of hybrid composite resins.

Science.gov (United States)

Garoushi, Sufyan; Lassila, Lippo; Hatem, Marwa; Shembesh, Muneim; Baady, Lugane; Salim, Ziad; Vallittu, Pekka

2013-01-01

The aim was to evaluate the color stability and water uptake of two hybrid composite resins polymerized in two different conditions after exposure to commonly consumed beverages. In addition, the effect of repolishing and bleaching on the stained composite was evaluated. Eighty specimens (12 mm × 12 mm × 3 mm) were made from two hybrid composite resins of shade A2. Forty specimens of each composite were divided into two groups (n = 20 per each) according to the curing method used (hand light cure HLC or oven light cure OLC). Then each group (HLC or OLC) was sub-divided randomly into four sub-groups (n = 5), which were immersed for 60 days in different beverages (distal water, coffee, tea and pepsi) and incubated at 37°C. Water uptake was measured during this time and followed by measurement of color difference (ΔE) by using a spectrophotometer. After complete staining, repolishing (grit 4000 FEPA at 300 rpm under water) and bleaching (40% hydrogen peroxide bleaching gel) were conducted. The repolished and bleached specimens were submitted to new color measurements. Color value of the specimens immersed in tea displayed the highest statistically significant (p pepsi was significantly lower than the others. After staining of the composite resins, both the bleaching and repolishing were able to reduce the ΔE value. All beverages used affected the color stability of tested composite resins. The effect of beverages on color change of composites depends on type of beverage and water uptake value of resins used. A superior whitening effect was obtained with repolishing technique compared to bleaching.

Effect of Ammonium Chloride on the Efficiency with Which Copper Sulfate Activates Marmatite: Change in Solution Composition and Regulation of Surface Composition

Directory of Open Access Journals (Sweden)

Shengdong Zhang

2018-06-01

Full Text Available Zinc sulfide minerals are the primary choice for zinc extraction and marmatite is one of the two most common zinc sulphide minerals (sphalerite and marmatite, therefore it is of great significance to study and optimize the flotation of marmatite. To improve the activation of copper sulfate on marmatite, a method involving the addition of ammonium chloride is devised. The method has been proven to be an effective way of improving the activation efficiency of copper sulfate towards marmatite under alkaline conditions. The strengthening mechanism was studied using micro-flotation, adsorption test, X-ray photoelectron spectroscopy, and by analyzing changes in solution composition. Flotation test results show that the activation effect of the copper sulfate towards marmatite is enhanced with the addition of ammonium chloride. According to the results of the adsorption measurements and X-ray photoelectron spectroscopy analysis, when the marmatite surface is activated using copper sulfate with added ammonia chloride, it adsorbs more copper sulfide and less copper hydroxide and zinc hydroxide. These changes in surface composition are believed to occur via the following process: NH3(aq promotes the dissolution of zinc hydroxide and then facilitates the conversion of surface copper hydroxide to copper sulfide. In addition, the occurrence of Cu(NH3n2+ can promote the adsorption of copper ions (Cu2+ can be stored as Cu(NH3n2+ via complexation, and then, when the concentration of copper ions decreases, Cu2+ can be released through the decompositionof Cu(NH3n2+. Hence, the copper ion concentration can be maintained and this can facilitate the adsorption of Cu2+ on marmatite. Based on a comprehensive analysis of all our results, we propose that adding ammonium chloride to the copper sulfate changes the solution components (i.e., the presence of NH3(aq and Cu(NH3n2+ and then regulates the surface composition of marmatite. The change in surface composition

Visualization of Problem Solving Related to the Quantitative Composition of Solutions in the Dynamic "GeoGebra" Environment

Science.gov (United States)

Kostic, V. Dj.; Jovanovic, V. P. Stankov; Sekulic, T. M.; Takaci, Dj. B.

2016-01-01

Problem solving in the field of quantitative composition of solutions (QCS), expressed as mass share and molar concentration, is essential for chemistry students. Since successful chemistry education is based on different mathematical contents, it is important to be proficient in both mathematical and chemistry concepts as well as interconnections…

One-step solution combustion synthesis of Fe{sub 2}O{sub 3}/C nano-composites as anode materials for lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Li, Peiyang; Deng, Jiachun; Li, Ying [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Liang, Wei, E-mail: liangwei@tyut.edu.cn [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Kun [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Kang, Litao, E-mail: kangltxy@gmail.com [Nano-Energy Inorganic Materials Laboratory, College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zeng, Shaozhong; Yin, Shanhui; Zhao, Zhigang [Chery Automobile Co. Ltd., Wuhu 241006 (China); Liu, Xuguang; Yang, Yongzhen [College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Gao, Feng [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

2014-03-25

Highlights: • Fe{sub 2}O{sub 3}/C composite anode materials were prepared by a solution combustion process. • The carbon content could be adjusted by regulating the ratio of oxidizer/fuel. • The Fe{sub 2}O{sub 3}/C composite showed capacity 470 mA h g{sup −1} at the 80th cycle at 125 mA g{sup −1}. -- Abstract: This article describes a one-step solution combustion route (within 30 min at 350 °C in air) to prepare Fe{sub 2}O{sub 3} anode materials for lithium ion batteries (LIBs) from Fe(NO{sub 3}){sub 3}⋅9H{sub 2}O solution with citric acid. XRD, SEM-EDX and TEM showed that the product consisted a mixture of nano-sized α-Fe{sub 2}O{sub 3} and γ-Fe{sub 2}O{sub 3} crystals that agglomerated into porous particles. Significantly, in situ formed carbon could be introduced into the product (i.e., Fe{sub 2}O{sub 3}/C nano-composites) by simply increasing the dosage of citric acid in the precursor solution. The as-prepared Fe{sub 2}O{sub 3}/C nano-composite exhibited high reversible capacities of 470 and 419 mA h g{sup −1} at the 80th and 200th cycles with a current density of 125 mA g{sup −1}, which are much higher than those of counterparts without carbon (i.e., Fe{sub 2}O{sub 3} nano-particles). Comparison experiments correlated with the performance improvement of Fe{sub 2}O{sub 3}/C nano-composites with in situ formed carbon, well-developed mesopores and relatively high specific surface areas.

High strength Ni based composite reinforced by solid solution W(Al) obtained by powder metallurgy

International Nuclear Information System (INIS)

Zhao Bo; Zhu Changjun; Ma Xianfeng; Zhao Wei; Tang Huaguo; Cai Shuguang; Qiao Zhuhui

2007-01-01

The solid-solution-particle reinforced W(Al)-Ni composites were successfully fabricated by using mechanical alloying (MA) and hot-pressing (HP) technique when the content of Ni is between 45 wt% and 55 wt%. Besides, samples of various original component ratio of Al 50 W 50 to Ni have been fabricated, and the corresponding microcomponents and mechanical properties such as microhardness, ultimate tensile strength and elongation were characterized and discussed. The optimum ultimate tensile strength under the experiment conditions is 1868 MPa with elongation of 10.21% and hardness of 6.62 GPa. X-ray diffraction (XRD), FE-SEM and energy dispersive analysis of X-rays (EDS) were given to analysis the components and morphology of the composite bulk specimens

One-step preparation of silver–polyaniline nanotube composite for non-enzymatic hydrogen peroxide detection

Energy Technology Data Exchange (ETDEWEB)

Lorestani, Farnaz, E-mail: Farnaz.lorestani@siswa.um.edu.my; Shahnavaz, Zohreh; Nia, Pooria Moozarm; Alias, Y.; Manan, Ninie S.A., E-mail: niniemanan@um.edu.my

2015-08-30

Graphical abstract: - Highlights: • Silver nanoparticle-decorated polyaniline nanotube composites (AgNPs–PANINTs) have been fabricated through a one step modified method without adding any extra acids, template and surface modifier. • The sensor showed excellent selectivity, reproducibility, and stability properties. • The AgNPs–PANINTs composite that prepared with silver ammonia solution (Ag(NH{sub 3}){sub 2}OH) exhibits better electrochemical performance than the AgNPs–PANINTs composite that was prepared with silver nitrite (AgNO{sub 3}) due to smaller size and higher surface area of silver nanoparticle (AgNPs) in the composite. • The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of PANI to Ag(NH{sub 3}){sub 2}OH (0.04 M). - Abstract: A modified glassy carbon electrode with silver nanoparticles–polyaniline nanotubes (AgNPs–PANINTs) composite is used as a non-enzymatic nanobiosensor for detecting hydrogen peroxide (H{sub 2}O{sub 2}). The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of PANI to Ag(NH{sub 3}){sub 2}OH (0.04 M). Field emission scanning electron microscope images and their size distribution diagrams indicated that using the silver ammonia complex instead of silver nitrate caused uniform distribution of nanometer-sized silver nanoparticles with a narrow size distribution in the composite. The corresponding calibration curve for the current response showed a linear detection range of 0.1–90 mM (R{sup 2} = 0.9986), while the limit of detection was estimated to be 0.2 μM at the signal to noise ratio of 3.

Using Central Composite Experimental Design to Optimize the Degradation of Tylosin from Aqueous Solution by Photo-Fenton Reaction

Directory of Open Access Journals (Sweden)

Abd Elaziz Sarrai

2016-05-01

Full Text Available The feasibility of the application of the Photo-Fenton process in the treatment of aqueous solution contaminated by Tylosin antibiotic was evaluated. The Response Surface Methodology (RSM based on Central Composite Design (CCD was used to evaluate and optimize the effect of hydrogen peroxide, ferrous ion concentration and initial pH as independent variables on the total organic carbon (TOC removal as the response function. The interaction effects and optimal parameters were obtained by using MODDE software. The significance of the independent variables and their interactions was tested by means of analysis of variance (ANOVA with a 95% confidence level. Results show that the concentration of the ferrous ion and pH were the main parameters affecting TOC removal, while peroxide concentration had a slight effect on the reaction. The optimum operating conditions to achieve maximum TOC removal were determined. The model prediction for maximum TOC removal was compared to the experimental result at optimal operating conditions. A good agreement between the model prediction and experimental results confirms the soundness of the developed model.

Evaluation of CNTs/MnO{sub 2} composite for adsorption of {sup 60}Co(II), {sup 65}Zn(II) and Cd(II) ions from aqueous solutions

Energy Technology Data Exchange (ETDEWEB)

Sharaf El-Deen, Sahar E.A.; Moussa, Saber I.; Mekawy, Zakaria A.; Shehata, Mohamed K.K.; Someda, Hanan H. [Atomic Energy Authority, Inshas (Egypt). Dept. of Nuclear Chemistry; Sadeek, Sadeek A. [Zagazig Univ. (Egypt). Dept. of Chemistry

2017-03-01

CNTs/MnO{sub 2} composite was synthesized by a co-precipitation method after preparation of carbon nanotubes (CNTs) using a chemical oxidation method and was characterized using Fourier transformer infrared (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The synthesized CNTs/MnO{sub 2} composite was used as a sorbent for the removal of some radionuclides ({sup 60}Co and {sup 65}Zn-radioisotopes) and Cd (II) ions from aqueous solutions. Different parameters affecting the removal process including pH, contact time and metal ion concentration were investigated. Isotherm and kinetic models were studied. Adsorption data was interpreted in terms of both Freundlich and Langmuir isotherms and indicated that the CNTs/MnO{sub 2} composite complied well with both Langmuir and Freundlich models for {sup 60}Co and Cd(II) ions and with the Freundlich model only for the {sup 65}Zn radioisotope. A pseudo-second-order model was effectively employed to describe the adsorption behavior of {sup 60}Co, {sup 65}Zn and Cd(II) ions. Desorption of {sup 60}Co and {sup 65}Zn and Cd(II) ions from loaded samples was studied using different eluents.

Self-healing composites: in-situ repair solutions

NARCIS (Netherlands)

Coope, T.S.; Luterbacher, R.; Turkenburg, D.H.; Fischer, H.R.; Bond, I.P.

2015-01-01

Realising self-healing composites in a commercial environment remains a challenge for the transport sector. Herein, this research considers the design envelope and the implications of embedding self-healing agents into commercially relevant fibre reinforced polymer (FRP) composite applications. A

Modelling of high temperature interfacial reactions in continuously reinforced Ti/SiC metal matrix composites (MMCs)

International Nuclear Information System (INIS)

Fox, K.M.

1993-01-01

Previous experimental work by Gundel and Wawner showed that the matrix alloy has a strong effect on reaction layer growth in Ti alloy/SCS-6 composite systems. A finite difference technique was used to model the reaction layer growth, which predicts the same trends as those exhibited by the experimental data. Matrix alloying elements such as Mo and Cr in metastable β alloys will affect the equilibrium compositions and diffusivities in the matrix, but matrix diffusion is not found to be rate controlling. Regular solution thermodynamic models indicate that the main affect of matrix composition is in controlling carbon-flux through the reaction layer by altering equilibrium C-TiC-Ti interfacial compositions. (orig.)

Properties of PP/MWCNT-COOH /PP composites made by melt mixing versus solution cast /melt mixing methods

International Nuclear Information System (INIS)

Reinholds, I; Roja, Z; Zicans, J; Meri, R Merijs; Bitenieks, J

2015-01-01

An approach on improvement of the properties of polypropylene / carbon nanotube (PP/CNT) composites is reported. PP blend compositions with carboxylic acid functionalized multi-walled carbon nanotubes (MWCNT-COOH) at filler content 1.0 wt.% were researched. One part of the composites was manufactured by direct thermoplastic mixing PP with the filler, but the other one was made from solution casted masterbatch with the following thermoplastic mixing. An increase of mechanical properties (Young's modulus, storage modulus and tensile strength), compared to an increase of glass transition temperature indicated a reinforcement effect of CNTs on PP matrix, determined from the tensile tests and differential mechanical analysis (DMA), while the elongation was reduced, compared to PP matrix. By differential scanning calorimetry (DSC) analysis, the effect of nanofiller on the reorganization of PP crystallites was observed. A noticeable enhanced effect on increase of the crystallization temperature was indicated for masterbatch manufactured composite. An increase of thermal stability was also observed, compared to pristine PP and the composite made by direct thermoplastic mixing PP with the filler

A boring solution

Energy Technology Data Exchange (ETDEWEB)

Radiuk, M I; Iushkova, N E; Kozubovskii, A I

1979-10-25

A boring solution is being patented for boring for oil and gas, which can be used in wells, where the temperature of the circulating liquid reaches 100/sup 0/. Polyvinyl acetate emulsion (PVE) is added for the purpose of decreasing viscosity of the solution at a temperature of agression into the boring solution containing clay, water, carboxymethylcellulose (CBC), a chloride from the number of sodium, potassium, or magnesium chlorides. The solution has the following composition in %: clay, 10 to 20; CBC, 1.5 to 2.0; chloride, 5 to 20; PVE, 0.5 to 2; water, up to 100. In accordance to GOST 1000-62 for the accepted PVE, the compound has the following composition, in %: monomer, 0.8; dry residue, greater than or equal to 50; plasticizer (tributyl phthalate), 5 to 15. The boring solution is processed according to the following method. The original solution, containing clay, water, salts, receives 1.5 to 2% CBC and afterwards it is processed with 0.5 to 2% PVE.

Effect of solvent composition on the limiting current of anodic dissolution of tungsten in aqueous-ethanol solutions of alkali

International Nuclear Information System (INIS)

Konoplyantseva, N.A.; L'vova, L.A.; Davydov, A.D.; AN SSSR, Moscow. Inst. Ehlektrokhimii)

1987-01-01

The effect of quantitative composition of solvent on tungsten anodic dissolution in aqueous-ethanol solutions of KOH is studied. It is shown that with an increase in ethanol content in aqueous-ethanol solutions of alkali the limiting current of tungsten anodic dissolution decreases. An increase in KOH concentration in certain limits (in ethanol solutions it is the range between 0.75 and 1.0 M KOH) results in the increase of the limiting current; with further increase in solution concentration the limiting current decreases, which can be related to the change of the limiting stage. An assumption is made that total reaction of tungsten anodic dissolution and the main reasons for the limiting current appearance do not change from aqueous to aqueous-ethanol and ethanol solutions of alkali

Finite element based composite solution for neutron transport problems

International Nuclear Information System (INIS)

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

1995-01-01

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

Effects of adhesive used as modeling liquid on the stability of the color and opacity of composites.

Science.gov (United States)

Araujo, Fernanda Santos; Barros, Mellany Cristie Ramos; Santana, Márcia Luciana Carregosa; de Jesus Oliveira, Ludmila Smith; Silva, Paula Fernanda Damasceno; Lima, Giana da Silveira; Faria-E-Silva, André Luis

2018-04-01

This study evaluated the effects of adhesive type used as modeling liquid on the stability of the color and opacity of composites submitted to thermal cycling in staining solutions followed by a bleaching procedure. Thirty cylinder-shaped composite specimens (10 mm diameter × 1.5 mm thickness) were built using or not using (control) an adhesive (Adper Universal or Scotchbond Multipurpose) as the modeling liquid. After polishing procedures, the color and opacity were measured, and the specimens were submitted to 200 thermal cycles with 10 s of dwell time in baths of grape juice at 5°C, water at 37°C, and coffee at 55°C. Changes in opacity and color caused by the staining solutions were measured. Then, the specimens were bleached with 35% hydrogen peroxide for 45 minutes followed by color/opacity measurements. Data were analyzed by ANOVA and Tukey's test (α = 0.05). The use of modeling liquids did not affect the initial color and opacity of composite. Reduced changes to color (E 00  = 3.44) and opacity (+2.67%) were observed for specimens modeled using Adper Universal. Bleaching procedures reduced the color (E 00  = 1.9-3.8) and opacity (-2.3 to 3.1%) alterations caused by staining solutions but were unable to restore the values observed at baseline. The use of universal adhesive as modeling liquid significantly reduced the color and opacity changes caused by staining solutions, and the bleaching procedure partially re-established the opacity and color of the composites. This study evaluates whether using adhesive systems for modeling a composite affects the color and opacity changes caused by staining solutions followed by a bleaching procedure. The findings suggest that the use of a universal adhesive as modeling liquid can reduce the alterations in optical properties caused by staining solutions, and the application of high-concentrated hydrogen peroxide over the composite reduce the color changes without fully recover the initial color. © 2018

The Interaction between Zein and Lecithin in Ethanol-Water Solution and Characterization of Zein–Lecithin Composite Colloidal Nanoparticles

Science.gov (United States)

Dai, Lei; Sun, Cuixia; Wang, Di; Gao, Yanxiang

2016-01-01

Lecithin, a naturally small molecular surfactant, which is widely used in the food industry, can delay aging, enhance memory, prevent and treat diabetes. The interaction between zein and soy lecithin with different mass ratios (20:1, 10:1, 5:1, 3:1, 2:1, 1:1 and 1:2) in ethanol-water solution and characterisation of zein and lecithin composite colloidal nanoparticles prepared by antisolvent co-precipitation method were investigated. The mean size of zein-lecithin composite colloidal nanoparticles was firstly increased with the rise of lecithin concentration and then siginificantly decreased. The nanoparticles at the zein to lecithin mass ratio of 5:1 had the largest particle size (263 nm), indicating that zein and lecithin formed composite colloidal nanoparticles, which might aggregate due to the enhanced interaction at a higher proportion of lecithin. Continuing to increase lecithin concentration, the zein-lecithin nanoparticles possibly formed a reverse micelle-like or a vesicle-like structure with zein in the core, which prevented the formation of nanoparticle aggregates and decreased the size of composite nanoparticles. The presence of lecithin significantly reduced the ζ-potential of zein-lecithin composite colloidal nanoparticles. The interaction between zein and lecithin enhanced the intensity of the fluorescence emission of zein in ethanol-water solution. The secondary structure of zein was also changed by the addition of lecithin. Differential scanning calorimetry thermograms revealed that the thermal stability of zein-lecithin nanoparticles was enhanced with the rise of lecithin level. The composite nanoparticles were relatively stable to elevated ionic strengths. Possible interaction mechanism between zein and lecithin was proposed. These findings would help further understand the theory of the interaction between the alcohol soluble protein and the natural small molecular surfactant. The composite colloidal nanoparticles formed in this study can

Chemically and compositionally modified solid solution disordered multiphase nickel hydroxide positive electrode for alkaline rechargeable electrochemical cells

Science.gov (United States)

Ovshinsky, Stanford R.; Corrigan, Dennis; Venkatesan, Srini; Young, Rosa; Fierro, Christian; Fetcenko, Michael A.

1994-01-01

A high capacity, long cycle life positive electrode for use in an alkaline rechargeable electrochemical cell comprising: a solid solution nickel hydroxide material having a multiphase structure that comprises at least one polycrystalline .gamma.-phase including a polycrystalline .gamma.-phase unit cell comprising spacedly disposed plates with at least one chemical modifier incorporated around the plates, the plates having a range of stable intersheet distances corresponding to a 2.sup.+ oxidation state and a 3.5.sup.+, or greater, oxidation state; and at least one compositional modifier incorporated into the solid solution nickel hydroxide material to promote the multiphase structure.

End-Member Formulation of Solid Solutions and Reactive Transport

Energy Technology Data Exchange (ETDEWEB)

Lichtner, Peter C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-09-01

A model for incorporating solid solutions into reactive transport equations is presented based on an end-member representation. Reactive transport equations are solved directly for the composition and bulk concentration of the solid solution. Reactions of a solid solution with an aqueous solution are formulated in terms of an overall stoichiometric reaction corresponding to a time-varying composition and exchange reactions, equivalent to reaction end-members. Reaction rates are treated kinetically using a transition state rate law for the overall reaction and a pseudo-kinetic rate law for exchange reactions. The composition of the solid solution at the onset of precipitation is assumed to correspond to the least soluble composition, equivalent to the composition at equilibrium. The stoichiometric saturation determines if the solid solution is super-saturated with respect to the aqueous solution. The method is implemented for a simple prototype batch reactor using Mathematica for a binary solid solution. Finally, the sensitivity of the results on the kinetic rate constant for a binary solid solution is investigated for reaction of an initially stoichiometric solid phase with an undersaturated aqueous solution.

Mixing of water masses caused by a drifting iceberg affects bacterial activity, community composition and substrate utilization capability in the Southern Ocean.

Science.gov (United States)

Dinasquet, Julie; Richert, Inga; Logares, Ramiro; Yager, Patricia; Bertilsson, Stefan; Riemann, Lasse

2017-06-01

The number of icebergs produced from ice-shelf disintegration has increased over the past decade in Antarctica. These drifting icebergs mix the water column, influence stratification and nutrient condition, and can affect local productivity and food web composition. Data on whether icebergs affect bacterioplankton function and composition are scarce, however. We assessed the influence of iceberg drift on bacterial community composition and on their ability to exploit carbon substrates during summer in the coastal Southern Ocean. An elevated bacterial production and a different community composition were observed in iceberg-influenced waters relative to the undisturbed water column nearby. These major differences were confirmed in short-term incubations with bromodeoxyuridine followed by CARD-FISH. Furthermore, one-week bottle incubations amended with inorganic nutrients and carbon substrates (a mix of substrates, glutamine, N-acetylglucosamine, or pyruvate) revealed contrasting capacity of bacterioplankton to utilize specific carbon substrates in the iceberg-influenced waters compared with the undisturbed site. Our study demonstrates that the hydrographical perturbations introduced by a drifting iceberg can affect activity, composition, and substrate utilization capability of marine bacterioplankton. Consequently, in a context of global warming, increased frequency of drifting icebergs in polar regions holds the potential to affect carbon and nutrient biogeochemistry at local and possibly regional scales. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Kinetic Rate Law Parameter Measurements on a Borosilicate Waste Glass: Effect of Temperature, pH, and Solution Composition on Alkali Ion Exchange

International Nuclear Information System (INIS)

Pierce, Eric M.; McGrail, B PETER.; Icenhower, J P.; Rodriguez, Elsa A.; Steele, Jackie L.; Baum, Steven R.

2004-01-01

The reaction kinetics of glass is controlled by matrix dissolution and ion exchange (IEX). Dissolution of an alkali-rich simulated borosilicate waste glass was investigated using single-pass flow-through (SPFT) experiments. Experiments were conducted as a function of temperature, pH, and solution composition by varying the SiO 2 (aq) activity in the influent solution. Results showed that under dilute conditions matrix dissolution increased with increasing pH and temperature, and decreased with increasing SiO 2 (aq) activity. IEX rates decreased with increasing pH and temperature, and increased with increasing SiO 2 (aq) activity. Over the solution composition range interrogated in this study the dominant dissolution mechanism changed from matrix dissolution to IEX. These results suggest that ''secondary'' reactions may become dominant under certain environmental conditions and emphasize the need to incorporate these reactions into dissolution rate models

Displacement potential solution of a guided deep beam of composite materials under symmetric three-point bending

Science.gov (United States)

Rahman, M. Muzibur; Ahmad, S. Reaz

2017-12-01

An analytical investigation of elastic fields for a guided deep beam of orthotropic composite material having three point symmetric bending is carried out using displacement potential boundary modeling approach. Here, the formulation is developed as a single function of space variables defined in terms of displacement components, which has to satisfy the mixed type of boundary conditions. The relevant displacement and stress components are derived into infinite series using Fourier integral along with suitable polynomials coincided with boundary conditions. The results are presented mainly in the form of graphs and verified with finite element solutions using ANSYS. This study shows that the analytical and numerical solutions are in good agreement and thus enhances reliability of the displacement potential approach.

Corrosion behaviour of groundnut shell ash and silicon carbide hybrid reinforced Al-Mg-Si alloy matrix composites in 3.5% NaCl and 0.3M H2SO4 solutions

Directory of Open Access Journals (Sweden)

Kenneth Kanayo ALANEME

2015-05-01

Full Text Available The corrosion behaviour of Al-Mg-Si alloy based composites reinforced with groundnut shell ash (GSA and silicon carbide (SiC was investigated. The aim is to assess the corrosion properties of Al-Mg-Si alloy based hybrid reinforced composites developed using different mix ratios of GSA (a cheaply processed agro waste derivative which served as partial replacement for SiC and SiC as reinforcing materials. GSA and SiC mixed in weight ratios 0:1, 1:3, 1:1, 3:1, and 1:0 were utilized to prepare 6 and 10 wt% of the reinforcing phase with Al‐Mg‐Si alloy as matrix using two‐step stir casting method. Mass loss and corrosion rate measurement was used to study the corrosion behaviour of the produced composites in 3.5% NaCl and 0.3M H2SO4 solutions. The results show that the Al-Mg-Si alloy based composites containing 6 and 10 wt% GSA and SiC in varied weight ratios were resistant to corrosion in 3.5% NaCl solution. The composites were however more susceptible to corrosion in 0.3M H2SO4 solution (in comparison with the 3.5% NaCl solution. It was noted that the Al-Mg-Si/6 wt% GSA-SiC hybrid composite grades containing GSA and SiC in weight ratio 1:3 and 3:1 respectively exhibited superior corrosion resistance in the 0.3M H2SO4 solution compared to other composites produced for this series. In the case of the Al-Mg-Si/10 wt% GSA-SiC hybrid composite grades, the corrosion resistance was relatively superior for the composites containing a greater weight ratio of GSA (75% and 100% in 0.3M H2SO4 solution.

Temperature and metal exposure affect membrane fatty acid composition and transcription of desaturases and elongases in fathead minnow muscle and brain.

Science.gov (United States)

Fadhlaoui, Mariem; Pierron, Fabien; Couture, Patrice

2018-02-01

In this study, we tested the hypothesis that metal exposure affected the normal thermal response of cell membrane FA composition and of elongase and desaturase gene transcription levels. To this end, muscle and brain membrane FA composition and FA desaturase (fads2, degs2 and scd2) and elongase (elovl2, elovl5 and elovl6) gene transcription levels were analyzed in fathead minnows (Pimephales promelas) acclimated for eight weeks to 15, 25 or 30°C exposed or not to cadmium (Cd, 6μg/l) or nickel (Ni, 450 6μg/l). The response of membrane FA composition to temperature variations or metal exposure differed between muscle and brain. In muscle, an increase of temperature induced a decrease of polyunsaturated FA (PUFA) and an increase of saturated FA (SFA) in agreement with the current paradigm. Although a similar response was observed in brain between 15 and 25°C, at 30°C, brain membrane unsaturation was higher than predicted. In both tissues, metal exposure affected the normal thermal response of membrane FA composition. The transcription of desaturases and elongases was higher in the brain and varied with acclimation temperature and metal exposure but these variations did not generally reflect changes in membrane FA composition. The mismatch between gene transcription and membrane composition highlights that several levels of control other than gene transcription are involved in adjusting membrane FA composition, including post-transcriptional regulation of elongases and desaturases and de novo phospholipid biosynthesis. Our study also reveals that metal exposure affects the mechanisms involved in adjusting cell membrane FA composition in ectotherms. Copyright © 2017 Elsevier Inc. All rights reserved.

Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

Science.gov (United States)

Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

2015-03-15

Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland. Copyright © 2015 Elsevier Ltd. All rights reserved.

Germination conditions affect selected quality of composite wheat-germinated brown rice flour and bread formulations.

Science.gov (United States)

Charoenthaikij, Phantipha; Jangchud, Kamolwan; Jangchud, Anuvat; Prinyawiwatkul, Witoon; Tungtrakul, Patcharee

2010-08-01

Brown rice has been reported to be more nutritious after germination. Germinated brown rice flours (GBRFs) from different steeping conditions (in distilled water [DI, pH 6.8] or in a buffer solution [pH 3] for either 24 or 48 h at 35 degrees C) were evaluated in this study. GBRF obtained from brown rice steeped at pH 3 for 48 h contained the highest amount of free gamma aminobutyric acid (GABA; 67 mg/100 g flour). The composite flour (wheat-GBRF) at a ratio of 70 : 30 exhibited significantly lower peak viscosity (PV) (56.99 - 132.45 RVU) with higher alpha-amylase activity (SN = 696 - 1826) compared with those of wheat flour (control) (PV = 136.46 RVU and SN = 1976). Bread formulations, containing 30% GBRF, had lower loaf volume and greater hardness (P rice flour (BRF). Acceptability scores for aroma, taste, and flavor of breads prepared with or without GBRFs (30% substitution) were not significantly different, with the mean score ranging from 6.1 (like slightly) to 7 (like moderately). Among the bread formulations containing GBRF, the one with GBRF prepared after 24 h steeping at pH 3 had a slightly higher (though not significant) overall liking score (6.8). This study demonstrated that it is feasible to substitute wheat flour with up to 30% GBRF in bread formulation without negatively affecting sensory acceptance. Practical Application: Our previous study revealed that flours from germinated brown rice have better nutritional properties, particularly gamma-aminobutyric acid (GABA), than the nongerminated one. This study demonstrated feasibility of incorporating up to 30% germinated brown rice flour in a wheat bread formulation without negatively affecting sensory acceptance. In the current United States market, this type of bread may be sold as frozen bread which would have a longer shelf life. Further study is thus needed.

Remnant trees affect species composition but not structure of tropical second-growth forest.

Science.gov (United States)

Sandor, Manette E; Chazdon, Robin L

2014-01-01

Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

Synthesis of (U,Zr)C solid solutions under exothermic conditions

International Nuclear Information System (INIS)

Wang, L.L.; Moore, H.G.; Gladson, J.W.

1993-01-01

The reactions of forming (U,Zr)C solid solutions from their elemental components or similarly less stable reactants such as UC 2 are strongly exothermic due to the high stability of these solid solutions. A simple approach of utilizing this heat of formation energy to assist the solid solution reaction process is to intimately mix the less stable reactant powders and then pressed them into a compact. The compact is then heated to the ignition temperature of the reaction. The feasibility of this reaction method to synthesize (U,Zr)C solid solutions has been demonstrated in this study. The preliminary results also show that both the initial composition and the heating rate have a significant effect on the nature of the reaction process. As expected the degree of powder mixing was also found to affect the completeness of the reaction

Microbial community composition affects soil fungistasis.

Science.gov (United States)

de Boer, Wietse; Verheggen, Patrick; Klein Gunnewiek, Paulien J A; Kowalchuk, George A; van Veen, Johannes A

2003-02-01

Most soils inhibit fungal germination and growth to a certain extent, a phenomenon known as soil fungistasis. Previous observations have implicated microorganisms as the causal agents of fungistasis, with their action mediated either by available carbon limitation (nutrient deprivation hypothesis) or production of antifungal compounds (antibiosis hypothesis). To obtain evidence for either of these hypotheses, we measured soil respiration and microbial numbers (as indicators of nutrient stress) and bacterial community composition (as an indicator of potential differences in the composition of antifungal components) during the development of fungistasis. This was done for two fungistatic dune soils in which fungistasis was initially fully or partly relieved by partial sterilization treatment or nutrient addition. Fungistasis development was measured as restriction of the ability of the fungi Chaetomium globosum, Fusarium culmorum, Fusarium oxysporum, and Trichoderma harzianum to colonize soils. Fungistasis did not always reappear after soil treatments despite intense competition for carbon, suggesting that microbial community composition is important in the development of fungistasis. Both microbial community analysis and in vitro antagonism tests indicated that the presence of pseudomonads might be essential for the development of fungistasis. Overall, the results lend support to the antibiosis hypothesis.

Effects of atmospheric deposition nitrogen flux and its composition on soil solution chemistry from a red soil farmland, southeast China.

Science.gov (United States)

Cui, Jian; Zhou, Jing; Peng, Ying; Chan, Andrew; Mao, Jingdong

2015-12-01

A detailed study on the solution chemistry of red soil in South China is presented. Data are collected from two simulated column-leaching experiments with an improved setup to evaluate the effects of atmospheric N deposition (ADN) composition and ADN flux on agricultural soil acidification using a (15)N tracer technique and an in situ soil solution sampler. The results show that solution pH values decline regardless of the increase of the NH4(+)/NO3(-) ratio in the ADN composition or ADN flux, while exchangeable Al(3+), Ca(2+), Mg(2+), and K(+) concentrations increase at different soil depths (20, 40, and 60 cm). Compared with the control, ADN (60 kg per ha per year N, NH4(+)/NO3(-) ratio of 2 : 1) decreases solution pH values, increases solution concentrations of NO3(-)-N, Al(3+), Ca(2+) and Mg(2+) at the middle and lower soil depths, and promotes their removal. NH4(+)-N was not detected in red soil solutions of all the three soil layers, which might be attributed to effects of nitrification, absorption and fixation in farmland red soil. Some of the NO3(-)-N concentrations at 40-60 cm soil depth exceed the safe drinking level of 10 mg L(-1), especially when the ADN flux is beyond 60 kg ha(-1) N. These features are critical for understanding the ADN agro-ecological effects, and for future assessment of ecological critical loads of ADN in red soil farmlands.

Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes.

Science.gov (United States)

Gugliuzza, Annarosa; Perrotta, Maria Luisa; Drioli, Enrico

2016-05-16

This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

Controlled Bulk Properties of Composite Polymeric Solutions for Extensive Structural Order of Honeycomb Polysulfone Membranes

Directory of Open Access Journals (Sweden)

Annarosa Gugliuzza

2016-05-01

Full Text Available This work provides additional insights into the identification of operating conditions necessary to overcome a current limitation to the scale-up of the breath figure method, which is regarded as an outstanding manufacturing approach for structurally ordered porous films. The major restriction concerns, indeed, uncontrolled touching droplets at the boundary. Herein, the bulk of polymeric solutions are properly managed to generate honeycomb membranes with a long-range structurally ordered texture. Water uptake and dynamics are explored as chemical environments are changed with the intent to modify the hydrophilic/hydrophobic balance and local water floatation. In this context, a model surfactant such as the polyoxyethylene sorbitan monolaurate is used in combination with alcohols at different chain length extents and a traditional polymer such as the polyethersufone. Changes in the interfacial tension and kinematic viscosity taking place in the bulk of composite solutions are explored and examined in relation to competitive droplet nucleation and growth rate. As a result, extensive structurally ordered honeycomb textures are obtained with the rising content of the surfactant while a broad range of well-sized pores is targeted as a function of the hydrophilic-hydrophobic balance and viscosity of the composite polymeric mixture. The experimental findings confirm the consistency of the approach and are expected to give propulsion to the commercially production of breath figures films shortly.

Stress corrosion cracking of duplex stainless steels in caustic solutions

Science.gov (United States)

Bhattacharya, Ananya

susceptibility. Annealed and water quenched specimens were found to be immune to SCC in caustic environment. Aging treatment at 800°C gave rise to sigma and chi precipitates in the DSS. However, these sigma and chi precipitates, known to initiate cracking in DSS in chloride environment did not cause any cracking of DSS in caustic solutions. Aging of DSS at 475°C had resulted in '475°C embrittlement' and caused cracks to initiate in the ferrite phase. This was in contrast to the cracks initiating in the austenite phase in the as-received DSS. Alloy composition and microstructure of DSS as well as solution composition (dissolved ionic species) was also found to affect the electrochemical behavior and passivation of DSS which in turn plays a major role in stress corrosion crack initiation and propagation. Corrosion rates and SCC susceptibility of DSS was found to increase with addition of sulfide to caustic solutions. Corrosion films on DSS, characterized using XRD and X-ray photoelectron spectroscopy, indicated that the metal sulfide compounds were formed along with oxides at the metal surface in the presence of sulfide containing caustic environments. These metal sulfide containing passive films are unstable and hence breaks down under mechanical straining, leading to SCC initiations. The overall results from this study helped in understanding the mechanism of SCC in caustic solutions. Favorable slip systems in the austenite phase of DSS favors slip-induced local film damage thereby initiating a stress corrosion crack. Repeated film repassivation and breaking, followed by crack tip dissolution results in crack propagation in the austenite phase of DSS alloys. Result from this study will have a significant impact in terms of identifying the alloy compositions, fabrication processes, microstructures, and environmental conditions that may be avoided to mitigate corrosion and stress corrosion cracking of DSS in caustic solutions.

Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

KAUST Repository

Hellstrom, Sondra L.

2010-07-12

We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors of pentacene and C60, with bottom-contact mobilities of ?0.5 and ?1 cm2 V-1 s-1, respectively. This represents a clear step towards development of inexpensive, high-performance all-organic circuits. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Composition, structure and electrical properties of alumina barrier layers grown in fluoride-containing oxalic acid solutions

Energy Technology Data Exchange (ETDEWEB)

Jagminas, A. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)], E-mail: jagmin@ktl.mii.lt; Vrublevsky, I. [Department of Microelectricals, Belarusian State University of Informatics and Radioelectricals, 6 Brovka Street, Minsk 220013 (Belarus); Kuzmarskyte, J.; Jasulaitiene, V. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)

2008-04-15

The composition, structure and electrical properties of alumina barrier layers grown by anodic oxidation in F{sup -}-containing (FC) and F{sup -}-free (FF) oxalic acid solutions were studied using the re-anodizing/dissolution technique, Fourier-transformed infrared and X-ray photoelectron spectroscopy. These results confirmed formation in FC anodizing solutions of films structurally different from ones grown in FF oxalic acid baths. It was found that the barrier layer of FC alumina films is composed of two layers differing in the dissolution rate. These differences are related to the formation in the FC electrolyte of a barrier layer composed of a more microporous outer part and a thin, non-porous and non-scalloped inner part consisting of aluminum oxide and aluminum fluoride.

Composite templates synthesis of mesoporous titania from industrial titanyl sulfate solution under external outfields

International Nuclear Information System (INIS)

Tian Congxue

2008-01-01

The precursors of mesoporous titania were synthesized via supra-molecular self-assembly route induced by composite templates (CTAB/P-123) from industrial titanyl sulfate solution under ultrasonic irradiation, microwave and hydrothermal condition. The hydrolysis and polycondensation rates of TiOSO 4 solution were controlled by adjusting the pH value at about 1.0. Mesoporous titania with anatase phase was obtained after templates removal by calcinations. The as-prepared powder was characterized by X-ray diffraction (XRD), N 2 isothermal adsorption-desorption, HRTEM and SAD. External outfields with enhancing polar action and soft hydrothermal condition were beneficial to prepare better mesoporous TiO 2 . Ultrasonic vibration promoted the formation of mesoporous structure. Under microwave irradiation, mesoporous TiO 2 was synthesized with BET specific surface area of 190.6 m 2 g -1 , average pore diameter of 2.57 nm and crystal size of 13.65 nm. And ultrasonic irradiation, microwave and hydrothermal conditions were making for forming and stabilizing the mesoporous structure

Investigation into isomolar series of Al(NO/sub 3/)/sub 3/, Na/sub 3/VO/sub 4/ solution mixture and composition of solid phases

Energy Technology Data Exchange (ETDEWEB)

Chernysh, L F; Nakhodnova, A P; Makarova, R A [Donetskij Gosudarstvennyj Univ. (Ukrainian SSR)

1979-11-01

Conducted is investigation of properties of isomolar series of aluminium nitrate and sodium vanadate solutions at pH of the latter 12.5; 10.0; 7.0 and the temperature of 25 deg C using the methods of pH-metry, conductometry, ''seeming'' volume of precipitations, residual concentration of aluminium and vanadium. It is shown, that the composition property diagram of the system investigated does not reflect the true composition of solid-phase products of the reaction, which depends on the component ratio in solution. Bottom phases of isomolar series are mainly heterogeneous. At the excess of sodium vanadate solution and its high pH values conditions for the basic salt formation are created. At pH of the Na/sub 3/VO/sub 4/ solution of 12.5 and 10.0 and Al(NO/sub 3/)/sub 3/: Na/sub 3/VO/sub 4/ ratios 4:6 and 3:7 respectively obtained are the basic aluminium vanadates of the (AlOH)/sub 3/(VO/sub 4/)/sub 2/x 7.5H/sub 2/O and (AlOH)/sub 2/V/sub 2/O/sub 7/x5H/sub 2/O composition, some of their physicochemical properties being investigated.

Large-scale fluctuations in the diffusive decomposition of solid solutions

International Nuclear Information System (INIS)

Karpov, V.G.; Grimsditch, M.

1995-01-01

The concept of an instability in the classic Ostwald ripening theory with respect to compositional fluctuations is suggested. We show that small statistical fluctuations in the precipitate phase lead to gigantic Coulomb-like fluctuations in the solute concentration which in turn affect the ripening. As a result large-scale fluctuations in both the precipitate and solute concentrations appear. These fluctuations are characterized by amplitudes of the order of the average values of the corresponding quantities and by a space scale L∼(na) -1/2 which is considerably greater than both the average nuclear radius and internuclear distance. The Lifshitz-Slyozov theory of ripening is shown to remain locally applicable, over length scales much less than L. The implications of these findings for elastic light scattering in solid solutions that have undergone Ostwald ripening are considered

Large-scale fluctuations in the diffusive decomposition of solid solutions

Science.gov (United States)

Karpov, V. G.; Grimsditch, M.

1995-04-01

The concept of an instability in the classic Ostwald ripening theory with respect to compositional fluctuations is suggested. We show that small statistical fluctuations in the precipitate phase lead to gigantic Coulomb-like fluctuations in the solute concentration which in turn affect the ripening. As a result large-scale fluctuations in both the precipitate and solute concentrations appear. These fluctuations are characterized by amplitudes of the order of the average values of the corresponding quantities and by a space scale L~(na)-1/2 which is considerably greater than both the average nuclear radius and internuclear distance. The Lifshitz-Slyozov theory of ripening is shown to remain locally applicable, over length scales much less than L. The implications of these findings for elastic light scattering in solid solutions that have undergone Ostwald ripening are considered.

Method of Making an Electroactive Sensing/Actuating Material for Carbon Nanotube Polymer Composite

Science.gov (United States)

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

2009-01-01

An electroactive sensing or actuating material comprises a composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation of the composite when such composite is affected by an external stimulus. In another embodiment, the composite comprises a, third component of micro -sized to nano-sized particles of an electroactive ceramic that is also incorporated in the polymer matrix. The method for making the three-phase composite comprises either incorporating the carbon nanotubes in the polymer matrix before incorporation of the particles of ceramic or mixing the carbon nanotubes and particles of ceramic together in a solution before incorporation in the polymer matrix.

Survey of SSC12 regions affecting fatty acid composition of intramuscular fat using high density SNP data

Directory of Open Access Journals (Sweden)

María eMuñoz

2012-01-01

Full Text Available Fatty acid composition is a critical aspect of pork because it affects sensorial and technological aspects of meat quality and it is relevant for human health. Previous studies identified significant QTLs in porcine chromosome 12 for fatty acid profile of backfat and intramuscular fat. In the present study, 374 SNPs mapped in SSC12 from the 60K Porcine SNP Beadchip were used. We have combined linkage and association analyses with expression data analysis in order to identify regions of SSC12 that could affect fatty acid composition of intramuscular fat in longissimus muscle. The QTL scan showed a region around the 60 cM position that significantly affects palmitic fatty acid and two related fatty acid indexes. The Iberian QTL allele increased the palmitic content (+2.6% of mean trait. This QTL does not match any of those reported in the previous study on fatty acid composition of backfat, suggesting different genetic control acting at both tissues. The SNP association analyses showed significant associations with linolenic and palmitic acids besides several indexes. Among the polymorphisms that affect palmitic fatty acid and match the QTL region at 60 cM, there were three that mapped in the Phosphatidylcholine Transfer Protein (PCTP gene and one in the Acetyl-CoA Carboxylase  gene (ACACA. Interestingly one of the PCTP SNPs also affected significantly unsaturated and double bound indexes and the ratio between polyunsaturated/monounsaturated fatty acids. Differential expression was assessed on longissimus muscle conditional on the genotype of the QTL and on the most significant SNPs, according to the results obtained in the former analyses. Results from the microarray expression analyses, validated by RT-qPCR, showed that PCTP expression levels significantly vary depending on the QTL as well as on the own PCTP genotype. The results obtained with the different approaches point out the PCTP gene as a powerful candidate underlying the QTL for

EXACT SOLUTION OF HEAT CONDUCTION IN A TWO-DOMAIN COMPOSITE CYLINDER WITH AN ORTHOTROPIC OUTER LAYER

International Nuclear Information System (INIS)

AVILES-RAMOS, C.; RUDY, C.

2000-01-01

The transient exact solution of heat conduction in a two-domain composite cylinder is developed using the separation of variables technique. The inner cylinder is isotropic and the outer cylindrical layer is orthotropic. Temperature solutions are obtained for boundary conditions of the first and second kinds at the outer surface of the orthotropic layer. These solutions are applied to heat flow calorimeters modeling assuming that there is heat generation due to nuclear reactions in the inner cylinder. Heat flow calorimeter simulations are carried out assuming that the inner cylinder is filled with plutonium oxide powder. The first objective in these simulations is to predict the onset of thermal equilibrium of the calorimeter with its environment. Two types of boundary conditions at the outer surface of the orthotropic layer are used to predict thermal equilibrium. The procedure developed to carry out these simulations can be used as a guideline for the design of calorimeters. Another important application of these solutions is on the estimation of thermophysical properties of orthotropic cylinders. The thermal conductivities in the vertical, radial and circumferential directions of the orthotropic outer layer can be estimated using this exact solution and experimental data. Simultaneous estimation of the volumetric heat capacity and thermal conductivities is also possible. Furthermore, this solution has potential applications to the solution of the inverse heat conduction problem in this cylindrical geometry. An interesting feature of the construction of this solution is that two different sets of eigenfunctions need to be considered in the eigenfunction expansion. These eigenfunctions sets depend on the relative values of the thermal diffusivity of the inner cylinder and the thermal diffusivity in the vertical direction of the outer cylindrical layer

The Systematics of Activity-Composition Relations in Mg-Fe2+ Oxide and Silicate Solid Solutions

Science.gov (United States)

O'Neill, H. S.

2006-12-01

The need to quantify activity-composition relations of mineral solid solutions for petrologic modelling has prompted many experimental studies, but different studies on the same system often appear to show a startling lack of consistency. A good example is Mg-Fe2+ mixing in garnet (the pyrope-almandine join). This is understandable because the energies of mixing in solid solutions are often obtained experimentally as small difference between large numbers. In particular, the fallacy of using a sequential approach to data fitting to a thermodynamic model leads to the accumulated errors being artificially concentrated onto the last step of the fitting process, which is usually that part of the model dealing with the excess energies of mixing. This gives rise to erroneous activity-composition relations, often apparently showing complex deviations from ideality. Systemizing the results of many studies can reveal underlying patterns of behaviour while also identifying outliers and anomalies that may be worth reinvestigating. Davies and Navrotsky [1] showed that the energies of mixing of many different pairs of ions with the same charge correlated well with the difference in molar volumes of the end-members, within a particular crystal structure. This empirical work is now supported by theoretical calculations. It underlies the modern approach to melt/crystal trace-element partitioning. Provided an internally consistent dataset is used, an analogous correlation may be demonstrated across different crystal structures for the mixing of one pair of ions, such as Mg and Fe2+. Activity-composition relations in MgO-"FeO" magnesiowuestite solutions in equilibrium with iron metal were used to obtain the properties of Mg-Fe olivine solutions from magnesiowuestite/olivine partitioning [2]. New results at 1400 K, 1 bar and 1473 K, 25 kb (O'Neill and Pownceby, in prep.) confirm previous work that mixing in Mg-Fe olivine is regular (symmetrical) with W Mg-Fe = 2.5 kJ/mol, with an

Diffusion of aqueous solutions of ionic, zwitterionic, and polar solutes

Science.gov (United States)

Teng, Xiaojing; Huang, Qi; Dharmawardhana, Chamila Chathuranga; Ichiye, Toshiko

2018-06-01

The properties of aqueous solutions of ionic, zwitterionic, and polar solutes are of interest to many fields. For instance, one of the many anomalous properties of aqueous solutions is the behavior of water diffusion in different monovalent salt solutions. In addition, solutes can affect the stabilities of macromolecules such as proteins in aqueous solution. Here, the diffusivities of aqueous solutions of sodium chloride, potassium chloride, tri-methylamine oxide (TMAO), urea, and TMAO-urea are examined in molecular dynamics simulations. The decrease in the diffusivity of water with the concentration of simple ions and urea can be described by a simple model in which the water molecules hydrogen bonded to the solutes are considered to diffuse at the same rate as the solutes, while the remainder of the water molecules are considered to be bulk and diffuse at almost the same rate as pure water. On the other hand, the decrease in the diffusivity of water with the concentration of TMAO is apparently affected by a decrease in the diffusion rate of the bulk water molecules in addition to the decrease due to the water molecules hydrogen bonded to TMAO. In other words, TMAO enhances the viscosity of water, while urea barely affects it. Overall, this separation of water molecules into those that are hydrogen bonded to solute and those that are bulk can provide a useful means of understanding the short- and long-range effects of solutes on water.

Corrosion of Dental Au-Ag-Cu-Pd Alloys in 0.9 % Sodium Chloride Solution

International Nuclear Information System (INIS)

Chiba, Atsushi; Kusayanagi, Yukiharu

2005-01-01

Two Au-Ag-Cu-Pd dental casting alloys (Au:12% and 20%) used. The test solutions used 0.9 % NaCl solution (isotonic sodium chloride solution), 0.9 % NaCl solution containing 1 % lactic acid, and 0.9 % NaCl solution containing 1 % lactic acid and 0.1 mol dm -3 Na 2 S. The surface of two samples in three sample solutions was not natural discoloration during one year. The alloy containing 12 % gold was easily alloyed and the composition was uniform comparing with the alloy containing 20 % gold. The rest potentials have not a little effect after three months. The kinds of metals could not definitely from the oxidation and reduction waves of metal on the cyclic voltammograms. The dissolutions of gold and palladium were 12 % Au sample in the 0.9 % NaCl solution containing 1 % lactic acid and 0.1 mol dm -3 Na 2 S. The pH of solution had an affect on dissolution of copper, and sulfur ion had an affect on dissolution of silver. The copper dissolved amount from 20 % gold sample was about 26 times comparing with that of 12 % gold sample in the 0.9 % solution containing 1 % lactic acid. Corrosion products were silver chloride and copper chloride in NaCl solution, and silver sulfide and copper sulfide in NaCl solution containing Na 2 S

Chemical bonding and the equilibrium composition of Grignard reagents in ethereal solutions.

Science.gov (United States)

Henriques, André M; Barbosa, André G H

2011-11-10

A thorough analysis of the electronic structure and thermodynamic aspects of Grignard reagents and its associated equilibrium composition in ethereal solutions is performed. Considering methylmagnesium halides containing fluorine, chlorine, and bromine, we studied the neutral, charged, and radical species associated with their chemical equilibrium in solution. The ethereal solvents considered, tetrahydrofuran (THF) and ethyl ether (Et(2)O), were modeled using the polarizable continuum model (PCM) and also by explicit coordination to the Mg atoms in a cluster. The chemical bonding of the species that constitute the Grignard reagent is analyzed in detail with generalized valence bond (GVB) wave functions. Equilibrium constants were calculated with the DFT/M06 functional and GVB wave functions, yielding similar results. According to our calculations and existing kinetic and electrochemical evidence, the species R(•), R(-), (•)MgX, and RMgX(2)(-) must be present in low concentration in the equilibrium. We conclude that depending on the halogen, a different route must be followed to produce the relevant equilibrium species in each case. Chloride and bromide must preferably follow a "radical-based" pathway, and fluoride must follow a "carbanionic-based" pathway. These different mechanisms are contrasted against the available experimental results and are proven to be consistent with the existing thermodynamic data on the Grignard reagent equilibria.

Effects of Proteoliposome Composition and Draw Solution Types on Separation Performance of Aquaporin-Based Proteoliposomes

DEFF Research Database (Denmark)

Zhao, Yang; Vararattanavech, Ardcharaporn; Li, Xuesong

2013-01-01

Escherichia coli cells, and their separation properties were characterized by stopped-flow measurements. The current study systematically investigated the effect of proteoliposome composition (lipid type, protein-to-lipid ratio (PLR), and the addition of cholesterol) on water permeability and NaCl retention......Aquaporins are a large family of water transport proteins in cell membranes. Their high water permeability and solute rejection make them potential building blocks for high-performance biomimetic membranes for desalination. In the current study, proteoliposomes were prepared using AquaporinZ from...

Americium Separations from High-Salt Solutions Using Anion Exchange

International Nuclear Information System (INIS)

Barr, Mary E.; Jarvinen, Gordon D.; Stark, Peter C.; Chamberlin, Rebecca M.; Bartsch, Richard A.; Zhang, Z.Y.; Zhao, W.

2001-01-01

The aging of the US nuclear stockpile presents a number of challenges, including the increasing radioactivity of plutonium residues due to the ingrowth of 241 Am from the β-decay of 241 Pu. We investigated parameters that affect the sorption of Am onto anion-exchange resins from concentrated effluents derived from nitric acid processing of plutonium residues. These postevaporator wastes are nearly saturated solutions of acidic nitrate salts, and americium removal is complicated by physical factors, such as solution viscosity and particulates, as well as by the presence of large quantities of competing metals and acid. Single- and double-contact batch distribution coefficients for americium and neodymium from simple and complex surrogate solutions are presented. Varied parameters include the nitrate salt concentration and composition and the nitric acid concentration. We find that under these extremely concentrated conditions, Am(III) removal efficiencies can surpass 50% per contact. Distribution coefficients for both neodymium and americium are insensitive to solution acidity and appear to be driven primarily by low water activities of the solutions

Catalytic wet oxidation of ammonia solution: Activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst

International Nuclear Information System (INIS)

Hung, C.-M.

2009-01-01

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H 2 PtCl 6 , Pd(NO 3 ) 3 and Rh(NO 3 ) 3 . Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h -1 in the wet catalytic processes

Catalytic wet oxidation of ammonia solution: Activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst

Energy Technology Data Exchange (ETDEWEB)

Hung, C.-M. [Department of Industry Engineering and Management, Yung-Ta Institute of Technology and Commerce, 316 Chung-shan Road, Linlo, Pingtung 909, Taiwan (China)], E-mail: hungcm1031@gmail.com

2009-04-15

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H{sub 2}PtCl{sub 6}, Pd(NO{sub 3}){sub 3} and Rh(NO{sub 3}){sub 3}. Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h{sup -1} in the wet catalytic processes.

Catalytic wet oxidation of ammonia solution: activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst.

Science.gov (United States)

Hung, Chang-Mao

2009-04-15

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H(2)PtCl(6), Pd(NO(3))(3) and Rh(NO(3))(3). Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes.

Structural and compositional characterization of synthetic (Ca,Sr)-tremolite and (Ca,Sr)-diopside solid solutions

Science.gov (United States)

Gottschalk, M.; Najorka, J.; Andrut, M.

Tremolite (CaxSr1-x)2Mg5[Si8O22/(OH)2] and diopside (CaxSr1-x)Mg[Si2O6] solid solutions have been synthesized hydrothermally in equilibrium with a 1 molar (Ca,Sr)Cl2 aqueous solution at 750°C and 200 MPa. The solid run products have been investigated by optical, electron scanning and high resolution transmission electron microscopy, electron microprobe, X-ray-powder diffraction and Fourier-transform infrared spectroscopy. The synthesized (Ca,Sr)-tremolites are up to 2000 µm long and 30 µm wide, the (Ca,Sr)-diopsides are up to 150 µm long and 20 µm wide. In most runs the tremolites and diopsides are well ordered and chain multiplicity faults are rare. Nearly pure Sr-tremolite (tr0.02Sr-tr0.98) and Sr-diopside (di0.01Sr-di0.99) have been synthesized. A continuous solid solution series, i.e. complete substitution of Sr2+ for Ca2+ on M4-sites exists for (Ca,Sr)-tremolite. Total substitution of Sr2+ for Ca2+ on M2-sites can be assumed for (Ca,Sr)-diopsides. For (Ca,Sr)-tremolites the lattice parameters a, b and β are linear functions of composition and increase with Sr-content whereas c is constant. For the diopside series all 4 lattice parameters are a linear function of composition; a, b, c increase and β decreases with rising Sr-content. The unit cell volume for tremolite increases 3.47% from 906.68 Å3 for tremolite to 938.21 Å3 for Sr-tremolite. For diopside the unit cell volume increases 4.87 % from 439.91 Å3 for diopside to 461.30 Å3 for Sr-diopside. The observed splitting of the OH stretching band in tremolite is caused by different configurations of the next nearest neighbors (multi mode behavior). Resolved single bands can be attributed to the following configurations on the M4-sites: SrSr, SrCa, CaCa and CaMg. The peak positions of these 4 absorption bands are a linear function of composition. They are shifted to lower wavenumbers with increasing Sr-content. No absorption band due to the SrMg configuration on the M4-site is observed. This indicates

A compositional multiphase model for groundwater contamination by petroleum products: 2. Numerical solution

Science.gov (United States)

Baehr, Arthur L.; Corapcioglu, M. Yavuz

1987-01-01

In this paper we develop a numerical solution to equations developed in part 1 (M. Y. Corapcioglu and A. L. Baehr, this issue) to predict the fate of an immiscible organic contaminant such as gasoline in the unsaturated zone subsequent to plume establishment. This solution, obtained by using a finite difference scheme and a method of forward projection to evaluate nonlinear coefficients, provides estimates of the flux of solubilized hydrocarbon constituents to groundwater from the portion of a spill which remains trapped in a soil after routine remedial efforts to recover the product have ceased. The procedure was used to solve the one-dimensional (vertical) form of the system of nonlinear partial differential equations defining the transport for each constituent of the product. Additionally, a homogeneous, isothermal soil with constant water content was assumed. An equilibrium assumption partitions the constituents between air, water, adsorbed, and immiscible phases. Free oxygen transport in the soil was also simulated to provide an upper bound estimate of aerobic biodgradation rates. Results are presented for a hypothetical gasoline consisting of eight groups of hydrocarbon constituents. Rates at which hydrocarbon mass is removed from the soil, entering either the atmosphere or groundwater, or is biodegraded are presented. A significant sensitivity to model parameters, particularly the parameters characterizing diffusive vapor transport, was discovered. We conclude that hydrocarbon solute composition in groundwater beneath a gasoline contaminated soil would be heavily weighted toward aromatic constituents like benzene, toluene, and xylene.

Factors affecting Archaeal Lipid Compositions of the Sulfolobus Species

Science.gov (United States)

He, L.; Han, J.; Wei, Y.; Lin, L.; Wei, Y.; Zhang, C.

2010-12-01

Temperature is the best known variable affecting the distribution of the archaeal glycerol dibiphytanyl glycerol tetraethers (GDGTs) in marine and freshwater systems. Other variables such as pH, ionic strength, or bicarbonate concentration may also affect archaeal GDGTs in terrestrial systems. Studies of pure cultures can help us pinpoint the specific effects these variables may have on archaeal lipid distribution in natural environments. In this study, three Sulfolobus species (HG4, HB5-2, HB9-6) isolated from Tengchong hot springs (pH 2-3, temperature 73-90°C) in China were used to investigate the effects of temperature, pH, substrate, and type of strain on the composition of GDGTs. Results showed that increase in temperature had negative effects on the relative contents of GDGT-0 (no cyclopentyl rings), GDGT-1 (one cyclopentyl ring), GDGT-2 and GDGT-3 but positive effects on GDGT-4, GDGT-4', GDGT-5 and GDGT-5'. Increase in pH, on the other hand, had negative effects on GDGT-0, GDGT-1, GDGT-4', GDGT-5 and GDGT-5', and positive effects on GDGT-3 and GDGT-4. GDGT-2 remained relatively constant with changing pH. When the HG4 was grown on different substrates, GDGT-5 was five time more abundant in sucrose-grown cultures than in yeast extract- or sulfur- grown cultures, suggesting that carbohydrates may stimulate the production of GDGT-5. For all three species, the ring index (average number of rings) of GDGTs correlated positively with incubation temperature. In HG4, ring index was much lower at optimal pH (3.5) than at other pH values. Ring index of HB5-2 or HB9-6 is higher than that of HG4, suggesting that speciation may affect the degree of cyclization of GDGT of the Sulfolobus. These results indicate that individual archaeal lipids respond differently to changes in environmental variables, which may be also species specific.

Effect of solution concentration on MEH-PPV thin films

Science.gov (United States)

Affendi, I. H. H.; Sarah, M. S. P.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

2018-05-01

MEH-PPV thin films were prepared with a mixture of THF (tetrahydrofuran) solution deposited by spin coating method. The surface topology of MEH-PPV thin film were characterize by atomic force microscopy (AFM) and optical properties of absorption spectra were characterized by using Ultraviolet-visible-near-infrared (UV-Vis-NIR). The MEH-PPV concentration variation affects the surface and optical properties of the thin film where 0.5 mg/ml MEH-PPV concentration have a good surface topology provided the same film also gives the highest absorption coefficient were then deposited to a TiO2 thin film forming composite layer. The composite layer then shows low current flow of short circuit current of Isc = -5.313E-7 A.

Preparation and properties of electrodeposited Ni-TiO2 composite coating

Directory of Open Access Journals (Sweden)

Sukhdev Singh Bhogal

2015-03-01

Full Text Available Mechanical properties of cutting tool like microhardness, coating adhesiveness & corrosion resistance are some important parameters, which affects the tool life and further indirectly affects the component cost. In this paper Ni-TiO2 composite coating was prepared through electrocodeposition in order to improve the mechanical properties of tungsten carbide cutting tools. Microhardness of Ni-TiO2 composite layer have been studied by varying input current density (mA, pH vale of electrolyte & particle concentration of TiO2 in electrolyte bath. Microstructure and phase structure of composite layer were investigated using atomic force microscope (AFM, scanning electronic microscope (SEM and X-ray diffraction (XRD. Surface morphology of Ni-TiO2 coated layer shows fine grained structures is obtained at low currents with higher microhardness of composite coating. Maximum microhardness 1483 HV of coated layer is found at 15mA of current and at 4.5 pH of watt’s solution. It has also been seen that with the increase of Ti, microhardness of the layer is also increases.  

Performance assessment of MCM-48 ceramic composite membrane by separation of AlCl3 from aqueous solution.

Science.gov (United States)

Kumar Basumatary, Ashim; Kumar Ghoshal, Aloke; Pugazhenthi, G

2016-12-01

Three dimensional ordered mesoporous MCM-48 membrane was fabricated on a circular shaped ceramic support by in-situ hydrothermal method. The synthesized MCM-48 powder and MCM-48 ceramic composite membrane were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA) and field emission scanning electron microscopy (FESEM). The porosity and pore size of the composite membrane are reduced considerably by the deposition of MCM-48 on the support. The formation of MCM-48 is verified by the XRD analysis. Three stepwise mechanisms for surfactant removal are observed by TGA analysis. FESEM images clearly signify the deposition of MCM-48 on the ceramic support. The pure water flux of the support and MCM-48 composite membrane is found to be 3.63×10 -6 and 4.18×10 -8 m 3 /m 2 skPa, respectively. The above prepared MCM-48 ceramic composite membrane is employed for the removal of AlCl 3 from aqueous solution and the highest rejection of 81% is obtained at an applied pressure of 276kPa with salt concentration of 250ppm. Copyright © 2015 Elsevier Inc. All rights reserved.

Composite media for fluid stream processing, a method of forming the composite media, and a related method of processing a fluid stream

Science.gov (United States)

Garn, Troy G; Law, Jack D; Greenhalgh, Mitchell R; Tranter, Rhonda

2014-04-01

A composite media including at least one crystalline aluminosilicate material in polyacrylonitrile. A method of forming a composite media is also disclosed. The method comprises dissolving polyacrylonitrile in an organic solvent to form a matrix solution. At least one crystalline aluminosilicate material is combined with the matrix solution to form a composite media solution. The organic solvent present in the composite media solution is diluted. The composite media solution is solidified. In addition, a method of processing a fluid stream is disclosed. The method comprises providing a beads of a composite media comprising at least one crystalline aluminosilicate material dispersed in a polyacrylonitrile matrix. The beads of the composite media are contacted with a fluid stream comprising at least one constituent. The at least one constituent is substantially removed from the fluid stream.

Effect of solution composition on the adsorption and desorption of 137Cs on forest soils

International Nuclear Information System (INIS)

Staunton, S.; Wells, C.; Shaw, G.

2004-01-01

There is ongoing debate as to the pertinence of measurements of soil-liquid distribution coefficients in dilute suspension to the understanding and the prediction of the mobility of radionuclides in soil. This debate is particularly active in the case of radiocaesium. Several factors could cause significant discrepancies between measured and effective in situ distributions of radiocaesium. 1. Differences in solution composition, notably ionic strength and concentration in cations such as potassium and ammonium; 2. Differences in soil:solution ratio; 3. Time dependent reactions; 4. Reversibility of the adsorption reaction; 5. Concentration dependence of adsorption. We have attempted to assess the importance of some of these factors by studying 137 Cs adsorption on soils sampled from different horizons of a forest soil. Kd was measured in suspension. Soil:solution ratio and initial 137 Cs concentration and concentration of potassium and stable Cs in solution were varied. Adsorption and desorption Kd values were measured under similar conditions and compared. Kd values were in the lower range of values reported in the literature (5-30 1/kg). Samples from surface layers showed no concentration dependence at trace additions of 137 Cs, whereas some decrease in Kd was observed with increasing 137 Cs concentration on the Ea horizon. Data obtained at different soil:solution ratios all fell on the same adsorption isotherms as those obtained by varying initial 137 Cs concentration. Stable caesium and, to a lesser extent, potassium inhibited 137 Cs adsorption. This effect was greater in the Ea horizon than the surface soils, probably due to the mineral content. For all samples the desorption Kd was greater than the adsorption Kd in the same solution, indicating a small but significant degree of irreversibility. (author)

Removal of Cr(VI and Toxic Ions from Aqueous Solutions and Tannery Wastewater Using Polymer-Clay Composites

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Abd El-Azeem Sallam

2017-10-01

Full Text Available Polymer-clay composites were prepared by natural zeolite (clinoptilolite or naturally local clay deposits in an N,N-methylene-bis-acrylamide as cross-linked. The resultant composites were used for the removal of Cr(VI from an aqueous solution. Additionally, their effects on soluble ions of tannery wastewater were investigated. The produced composites were characterized using X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, and scanning electron microscopy (SEM. The results showed that Cr(VI removal is dependent upon initial concentrations and pH. The adsorption quantity of Cr(VI onto the polymerized clay deposit followed by polymerized zeolite exhibited higher values than their original samples. The polymer-clay composite of clay deposit showed the highest removal of 76.3–100% overall initial concentrations of 10–50 mg L−1 and at initial pH of 2. Kinetics of Cr(VI removal by various sorbents was predicted using a pseudo–second order model. Our findings showed that the levels of salinity and various soluble ions (Cr2+, Na+, Cl− and SO42− in tannery wastewater are very high, and their levels were reduced after treatment, especially by polymerized sorbents. It could be concluded that the polymer-clay composites may be employed as a highly efficient sorbent for the removal of Cr(VI and toxic ions from the wastewater.

Floral resources and habitat affect the composition of hummingbirds at the local scale in tropical mountaintops

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LC Rodrigues

Full Text Available Hummingbird communities tend to respond to variation in resources, having a positive relationship between abundance and diversity of food resources and the abundance and/or diversity of hummingbirds. Here we examined the influence of floral resource availability, as well as seasonality and type of habitat on the composition of hummingbird species. The study was carried out in two habitats of eastern Brazilian mountaintops. A gradient representative of the structure of hummingbird community, based on species composition, was obtained by the ordination of samples using the method of non-metric multidimensional scaling. The composition of hummingbird species was influenced by the type of habitat and floral resource availability, but not by seasonality. Hummingbird communities differ between habitats mainly due to the relative abundance of hummingbird species. The variation in composition of hummingbird species with the variation in floral resource availability may be related to differences in feeding habits of hummingbirds. Hummingbird species with the longest bills visited higher proportions of ornithophilous species, while hummingbirds with shorter bills visited higher proportions of non-ornithophilous species. The results demonstrate that at local-scale the composition of hummingbird species is affected by the type of habitat and floral resources availability, but not by seasonality.

Floral resources and habitat affect the composition of hummingbirds at the local scale in tropical mountaintops.

Science.gov (United States)

Rodrigues, L C; Rodrigues, M

2015-01-01

Hummingbird communities tend to respond to variation in resources, having a positive relationship between abundance and diversity of food resources and the abundance and/or diversity of hummingbirds. Here we examined the influence of floral resource availability, as well as seasonality and type of habitat on the composition of hummingbird species. The study was carried out in two habitats of eastern Brazilian mountaintops. A gradient representative of the structure of hummingbird community, based on species composition, was obtained by the ordination of samples using the method of non-metric multidimensional scaling. The composition of hummingbird species was influenced by the type of habitat and floral resource availability, but not by seasonality. Hummingbird communities differ between habitats mainly due to the relative abundance of hummingbird species. The variation in composition of hummingbird species with the variation in floral resource availability may be related to differences in feeding habits of hummingbirds. Hummingbird species with the longest bills visited higher proportions of ornithophilous species, while hummingbirds with shorter bills visited higher proportions of non-ornithophilous species. The results demonstrate that at local-scale the composition of hummingbird species is affected by the type of habitat and floral resources availability, but not by seasonality.

Formation of soft magnetic high entropy amorphous alloys composites containing in situ solid solution phase

Science.gov (United States)

Wei, Ran; Sun, Huan; Chen, Chen; Tao, Juan; Li, Fushan

2018-03-01

Fe-Co-Ni-Si-B high entropy amorphous alloys composites (HEAACs), which containing high entropy solid solution phase in amorphous matrix, show good soft magnetic properties and bending ductility even in optimal annealed state, were successfully developed by melt spinning method. The crystallization phase of the HEAACs is solid solution phase with body centered cubic (BCC) structure instead of brittle intermetallic phase. In addition, the BCC phase can transformed into face centered cubic (FCC) phase with temperature rise. Accordingly, Fe-Co-Ni-Si-B high entropy alloys (HEAs) with FCC structure and a small amount of BCC phase was prepared by copper mold casting method. The HEAs exhibit high yield strength (about 1200 MPa) and good plastic strain (about 18%). Meanwhile, soft magnetic characteristics of the HEAs are largely reserved from HEAACs. This work provides a new strategy to overcome the annealing induced brittleness of amorphous alloys and design new advanced materials with excellent comprehensive properties.

Raman scattering quantitative analysis of the anion chemical composition in kesterite Cu2ZnSn(SxSe1−x)4 solid solutions

International Nuclear Information System (INIS)

Dimitrievska, Mirjana; Gurieva, Galina; Xie, Haibing; Carrete, Alex; Cabot, Andreu; Saucedo, Edgardo; 2UB, Departament d’Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona (Spain))" data-affiliation=" (Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1 2pl., 08930 Sant Adrià del Besòs, Barcelona (Spain); IN2UB, Departament d’Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona (Spain))" >Pérez-Rodríguez, Alejandro

2015-01-01

Highlights: • An optical method for the quantitative measurement of [S]/([S] + [Se]) in CZTSSe is presented. • It is based on Raman spectroscopy and covers whole S–Se range of compositions. • The proposed method is independent of crystal quality, experimental conditions and type of material. • The validity of the technique is proven by comparison with independent composition measurements (XRD and EQE). • Test of the method on the data published in the literature has given satisfactory results. - Abstract: A simple and non destructive optical methodology for the quantitative measurement of [S]/([S] + [Se]) anion composition in kesterite Cu 2 ZnSn(S x Se 1−x ) 4 (CZTSSe) solid solutions by means of Raman spectroscopy in the whole S–Se range of compositions has been developed. This methodology is based on the dependence of the integral intensity ratio of Raman bands sensitive to anion vibrations with the [S]/([S] + [Se]) composition of the kesterite solid solutions. The calibration of the parameters used in this analysis involved the synthesis of a set of CZTSSe powders by solid state reaction method, spanning the range from pure Cu 2 ZnSnS 4 to pure Cu 2 ZnSnSe 4 . The validity of the methodology has been tested on different sets of independent samples, including also non-stoichiometric device grade CZTSSe layers with different compositions and films that were synthesized by solution based processes with different crystalline quality. In all cases, the comparison of the results obtained from the analysis of the intensity of the Raman bands with independent composition measurements performed by different techniques as X-ray diffraction and external quantum efficiency has confirmed the satisfactory performance of the developed methodology for the quantitative analysis of these compounds, independently on the crystal quality or the method of synthesis. Further strong support on the methodology performance has been obtained from the analysis of a wider

Management type affects composition and facilitative processes in altoandine dry grassland

Science.gov (United States)

Catorci, Andrea; Cesaretti, Sabrina; Velasquez, Jose Luis; Burrascano, Sabina; Zeballos, Horacio

2013-10-01

We performed our study in the Dry Puna of the southern Peruvian Andes. Through a comparative approach we aimed to assess the effects of the two management systems, low grazing pressure by wild camelids vs. high grazing pressure by domestic livestock and periodic burning. Our general hypothesis was that the traditional high disturbance regime affects the dry Puna species diversity and composition through modifications of the magnitude of plant-plant-interactions and changes of the community structure due to shifts in species dominance. In 40 plots of 10 × 10 m, the cover value of each species was recorded and the species richness, floristic diversity, and community similarity of each treatment were compared. For each disturbance regime, differences of soil features (organic matter, carbon/nitrogen ratio, and potassium content) were tested. To evaluate plant-plant interactions, 4 linear transect divided into 500 plots of 10 × 10 cm were laid out and co-occurrence analysis was performed. We found that different disturbance regimes were associated with differences in the floristic composition, and that the high disturbance condition had lower species diversity and evenness. A decrease of tall species such as Festuca orthophylla and increase of dwarf and spiny Tetraglochin cristatum shrubs was observed as well. In addition, different disturbance intensities caused differences in the functional composition of the plant communities, since species with avoidance strategies are selected by high grazing pressure. High disturbance intensity was also associated to differences of soil features and to different clumped spatial structure of the dry Puna. Our results indicate also that: positive interactions are often species-specific mainly depending on the features of nurse and beneficiary species; the importance of positive interaction is higher at low grazing pressure than at high disturbance intensity; the magnitude and direction of the herbivory-mediated facilitation

The effect of biomolecules on the behaviour of CoCrMo alloy in various simulated physiological solutions

International Nuclear Information System (INIS)

Milošev, Ingrid

2012-01-01

Highlights: ► The behaviour of CoCrMo alloy is investigated in four simulated physiological solutions. ► The effect of synovial fluid significantly differs from the effect of organic components hitherto studied. ► In the presence of organic components carbon and nitrogen containing species are formed. ► Composition, structure and thickness of surface layers were determined by XPS. - Abstract: CoCrMo orthopaedic alloy was oxidized potentiostatically in various simulated physiological solutions in order to reveal differences in the composition, thickness and structure of the surface layers formed as a function of solution composition. X-ray photoelectron spectroscopy, combined with angle-resolved measurements and depth profiling, was used for the purpose. The following simulated physiological solutions were used: (1) 0.9% NaCl, (2) simulated Hanks physiological solution containing various inorganic salts, (3) simulated Hanks physiological solution containing an aliquot of synovial fluid retrieved at a primary operation, and (4) minimum essential medium containing various inorganic salts, amino acids and vitamins. No significant differences between alloy treated in these solutions were observed after oxidation in the passive region; the oxide films are a few nanometres thick and, except in NaCl solution, contain a small amount of calcium phosphate. After oxidation at a potential in the transpassive range, however, the oxide thickness increases considerably due to incorporation of cobalt and molybdenum oxides. Further, the concentration of calcium phosphate increases. The layers formed in minimum essential medium and Hanks solution containing synovial fluid comprise nitrogen and carbon containing species. The addition of synovial fluid significantly affects the behaviour in Hanks solution.

Polyvinyl alcohol/starch composite nanofibers by bubble electrospinning

Directory of Open Access Journals (Sweden)

Liu Zhi

2014-01-01

Full Text Available Bubble electrospinning exhibits profound prospect of industrialization of macro/ nano materials. Starch is the most abundant and inexpensive biopolymer. With the drawbacks of poor strength, water resistibility, thermal stability and processability of pure starch, some biodegradable synthetic polymers such as poly (lactic acid, polyvinyl alcohol were composited to electrospinning. To the best of our knowledge, composite nanofibers of polyvinyl alcohol/starch from bubble electrospinning have never been investigated. In the present study, nanofibers of polyvinyl alcohol/starch were prepared from bubble electrospinning. The processability and the morphology were affected by the weight ratio of polyvinyl alcohol and starchy. The rheological studies were in agreement with the spinnability of the electrospinning solutions.

Silver-zinc electrodeposition from a thiourea solution with added EDTA or HEDTA

International Nuclear Information System (INIS)

Oliveira, G.M. de; Carlos, I.A.

2009-01-01

This paper shows the study of silver-zinc electrodeposition from a thiourea solution with added (ethylenedinitrilo)tetraacetic acid (EDTA), disodium salt and N-(2-hydroxyethyl)ethylenediaminetriacetic acid (HEDTA), trisodium salt. Voltammetric results indicated that silver-zinc alloy can be obtained applying overpotential higher than 0.495 V, in Tu solution containing 1.0 x 10 -1 mol L -1 Zn(NO 3 ) 2 + 2.5 x 10 -2 mol L -1 AgNO 3 . This was due to silver(I) ion complexation with thiourea, which shifted the silver deposition potential to more negative value and due to silver-zinc alloy deposition, which occurred at potentials more positive than the potential to zinc deposition alone. EDTA or HEDTA did not significantly affect the silver and zinc deposition potentials, but decreased the current density for silver-zinc deposition. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses of the silver-zinc deposits showed that the morphology and composition changed as a function of the conditions of deposition, viz, deposition potential (E d ), deposition charge density (q d ) and solution composition (silver, EDTA and HEDTA concentrations). EDS analysis of the deposits showed sulphur (S) incorporated into the silver-zinc deposit, while SEM images showed that this sulphur content seemed to improve the silver-zinc morphology, as did the presence of EDTA and HEDTA in the solution, which enhanced the sulphur incorporation into the silver-zinc deposit. X-ray diffraction (XRD) analysis of the silver-zinc deposit showed that it was amorphous, irrespective of its composition and morphology

Conducting compositions of matter

Science.gov (United States)

Viswanathan, Tito (Inventor)

2000-01-01

The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

Application of Some Synthesized Polymeric Composite Resins for Removal of Some Metal Ions

International Nuclear Information System (INIS)

El-Zahhhar, A.A.; Abdel-Aziz, H.M.; Siyam, T.

2005-01-01

The ion-exchange and sorption characteristic of new polymeric composite resins, prepared by gamma radiation were experimentally studied. The composite resins shows high uptake for Co(II) and Eu(III) ions in aqueous solutions in wide range of ph. The selectivity of the resins to Co (II) or Eu (III) species in the presence of some competing ions and complexing agents (as Na + , Fe 3+ , EDTA Na 2 , etc.) was compared. Various factors that could affect the sorption behaviors of metal ions (Co (II) and Eu (III)) on the prepared polymeric composite resins were studied such as ionic strength, Contact time, volume mass ratio

Compositions comprising free-standing two-dimensional nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Barsoum, Michel W.; Gogotsi, Yury; Abdelmalak, Michael Naguib; Mashtalir, Olha

2017-12-05

The present invention is directed to methods of transferring urea from an aqueous solution comprising urea to a MXene composition, the method comprising contacting the aqueous solution comprising urea with the MXene composition for a time sufficient to form an intercalated MXene composition comprising urea.

DESIGN AND TECHNOLOGICAL SOLUTIONS FOR THE RESTORATION OF SEWERS USING ELEMENTS OF RECYCLED POLYMER COMPOSITE MATERIALS

Directory of Open Access Journals (Sweden)

GONCHARENKO D. F.

2017-01-01

Full Text Available Problem statement. Currently sanitary drainage systems of large cities in Ukraine are significantly worn down with prolonged use and due to inefficient solutions for protection of the structures from aggressive effects of the environment, poor quality of materials and construction and installation works during building. Restoration of performance characteristics, reliability and durability of sewer tunnels is the costly and technically complex task, which is urgently needed to be fulfilled to prevent accidents including those with serious environmental impact. Modern work technique and the materials used for restoration allow us to solve these problems with different levels of efficiency, while reducing the cost of restoration due to use of recycled polymeric raw material, as well as to improvement of technological solutions is a currently important direction of research. Purpose of the article. To develop solutions for restoring serviceability, reliability and durability of sewer tunnels taking into account the accumulated experience in renovation of water disposal networks. Conclusion. Use of components made of recycled polymer composite materials during restoring sewer tunnels has significant economic and environmental effects and allows to undertake repair work in hard-to-reach areas.

Box-Behnken experimental design for chromium(VI) ions removal by bacterial cellulose-magnetite composites.

Science.gov (United States)

Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Mihalache, Nicoleta; Botez, Adriana; Matei, Cristian; Berger, Daniela; Damian, Celina Maria; Ionita, Valentin

2016-10-01

In this study bacterial cellulose-magnetite composites were synthesised for the removal of chromium(VI) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the bacterial cellulose-magnetite composites and to reveal the uniform dispersion of nanomagnetite in the BC matrix. Magnetic properties were also measured to confirm the magnetite immobilization on bacterial cellulose membrane. The effects of initial Cr(VI) concentration, solution pH and solid/liquid ratio upon chromium removal were examined using the statistical Box-Behnken Design. Because of the possibility of magnetite dissolution during chromium(VI) adsorption, the degree of iron leaching was also analysed in the same conditions as Cr(VI) adsorption. From the factors affecting chromium(VI) adsorption the most important was solution pH. The highest Cr(VI) removal efficiency was observed at pH 4, accompanied by the lowest iron leaching in the solution. The adsorption experiments also indicated that the adsorption process of chromium(VI) is well described by Freundlich adsorption model. Our results proved that the BC-magnetite composites could be used for an efficient removal of chromium(VI) from diluted solutions with a minimum magnetite dissolution during operation. Copyright © 2016 Elsevier B.V. All rights reserved.

Bargaining for Equality. A Guide to Legal and Collective Bargaining Solutions for Workplace Problems that Particularly Affect Women.

Science.gov (United States)

Popkin, Mary; Ross, Diane

This is a guide to legal and collective bargaining solutions for workplace problems that particularly affect women. The first section of the guide presents a survey of legal remedies for discrimination including information on: (1) Title VII; (2) Equal Pay Act; (3) Executive Order 11246; (4) Age Discrimination in Employment Act; and (5) State Fair…

Confocal Raman microspectroscopy reveals a convergence of the chemical composition in methanogenic archaea from a Siberian permafrost-affected soil.

Science.gov (United States)

Serrano, Paloma; Hermelink, Antje; Lasch, Peter; de Vera, Jean-Pierre; König, Nicole; Burckhardt, Oliver; Wagner, Dirk

2015-12-01

Methanogenic archaea are widespread anaerobic microorganisms responsible for the production of biogenic methane. Several new species of psychrotolerant methanogenic archaea were recently isolated from a permafrost-affected soil in the Lena Delta (Siberia, Russia), showing an exceptional resistance against desiccation, osmotic stress, low temperatures, starvation, UV and ionizing radiation when compared to methanogens from non-permafrost environments. To gain a deeper insight into the differences observed in their resistance, we described the chemical composition of methanogenic strains from permafrost and non-permafrost environments using confocal Raman microspectroscopy (CRM). CRM is a powerful tool for microbial identification and provides fingerprint-like information about the chemical composition of the cells. Our results show that the chemical composition of methanogens from permafrost-affected soils presents a high homology and is remarkably different from strains inhabiting non-permafrost environments. In addition, we performed a phylogenetic reconstruction of the studied strains based on the functional gene mcrA to prove the different evolutionary relationship of the permafrost strains. We conclude that the permafrost methanogenic strains show a convergent chemical composition regardless of their genotype. This fact is likely to be the consequence of a complex adaptive process to the Siberian permafrost environment and might be the reason underlying their resistant nature. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chemical composition of the humus layer, mineral soil and soil solution of 150 forest stands in the Netherlands in 1990

NARCIS (Netherlands)

Vries, de W.; Leeters, E.E.J.M.

2001-01-01

A nationwide assessment of the chemical composition of the humus layer, mineral topsoil (0-30 cm) and soil solution in both topsoil and subsoil (60-100 cm) was made for 150 forest stands in the year 1990. The stands, which were part of the national forest inventory on vitality, included seven tree

Manipulating cinnamyl alcohol dehydrogenase (CAD) expression in flax affects fibre composition and properties

Science.gov (United States)

2014-01-01

Background In recent decades cultivation of flax and its application have dramatically decreased. One of the reasons for this is unpredictable quality and properties of flax fibre, because they depend on environmental factors, retting duration and growing conditions. These factors have contribution to the fibre composition, which consists of cellulose, hemicelluloses, lignin and pectin. By far, it is largely established that in flax, lignin reduces an accessibility of enzymes either to pectin, hemicelluloses or cellulose (during retting or in biofuel synthesis and paper production). Therefore, in this study we evaluated composition and properties of flax fibre from plants with silenced CAD (cinnamyl alcohol dehydrogenase) gene, which is key in the lignin biosynthesis. There is evidence that CAD is a useful tool to improve lignin digestibility and/or to lower the lignin levels in plants. Results Two studied lines responded differentially to the introduced modification due to the efficiency of the CAD silencing. Phylogenetic analysis revealed that flax CAD belongs to the “bona-fide” CAD family. CAD down-regulation had an effect in the reduced lignin amount in the flax fibre cell wall and as FT-IR results suggests, disturbed lignin composition and structure. Moreover introduced modification activated a compensatory mechanism which was manifested in the accumulation of cellulose and/or pectin. These changes had putative correlation with observed improved fiber’s tensile strength. Moreover, CAD down-regulation did not disturb at all or has only slight effect on flax plants’ development in vivo, however, the resistance against flax major pathogen Fusarium oxysporum decreased slightly. The modification positively affected fibre possessing; it resulted in more uniform retting. Conclusion The major finding of our paper is that the modification targeted directly to block lignin synthesis caused not only reduced lignin level in fibre, but also affected amount and

Dietary Resveratrol Does Not Affect Life Span, Body Composition, Stress Response, and Longevity-Related Gene Expression in Drosophila melanogaster.

Science.gov (United States)

Staats, Stefanie; Wagner, Anika E; Kowalewski, Bianca; Rieck, Florian T; Soukup, Sebastian T; Kulling, Sabine E; Rimbach, Gerald

2018-01-11

In this study, we tested the effect of the stilbene resveratrol on life span, body composition, locomotor activity, stress response, and the expression of genes encoding proteins centrally involved in ageing pathways in the model organism Drosophila melanogaster . Male and female w 1118 D. melanogaster were fed diets based on sucrose, corn meal, and yeast. Flies either received a control diet or a diet supplemented with 500 µmol/L resveratrol. Dietary resveratrol did not affect mean, median, and maximal life span of male and female flies. Furthermore, body composition remained largely unchanged following the resveratrol supplementation. Locomotor activity, as determined by the climbing index, was not significantly different between control and resveratrol-supplemented flies. Resveratrol-fed flies did not exhibit an improved stress response towards hydrogen peroxide as compared to controls. Resveratrol did not change mRNA steady levels of antioxidant ( catalase , glutathione-S-transferase , NADH dehydrogenase , glutathione peroxidase , superoxide dismutase 2 ) and longevity-related genes, including sirtuin 2 , spargel , and I'm Not Dead Yet . Collectively, present data suggest that resveratrol does not affect life span, body composition, locomotor activity, stress response, and longevity-associated gene expression in w 1118 D. melanogaster .

Dietary Resveratrol Does Not Affect Life Span, Body Composition, Stress Response, and Longevity-Related Gene Expression in Drosophila melanogaster

Directory of Open Access Journals (Sweden)

Stefanie Staats

2018-01-01

Full Text Available In this study, we tested the effect of the stilbene resveratrol on life span, body composition, locomotor activity, stress response, and the expression of genes encoding proteins centrally involved in ageing pathways in the model organism Drosophila melanogaster. Male and female w1118 D. melanogaster were fed diets based on sucrose, corn meal, and yeast. Flies either received a control diet or a diet supplemented with 500 µmol/L resveratrol. Dietary resveratrol did not affect mean, median, and maximal life span of male and female flies. Furthermore, body composition remained largely unchanged following the resveratrol supplementation. Locomotor activity, as determined by the climbing index, was not significantly different between control and resveratrol-supplemented flies. Resveratrol-fed flies did not exhibit an improved stress response towards hydrogen peroxide as compared to controls. Resveratrol did not change mRNA steady levels of antioxidant (catalase, glutathione-S-transferase, NADH dehydrogenase, glutathione peroxidase, superoxide dismutase 2 and longevity-related genes, including sirtuin 2, spargel, and I’m Not Dead Yet. Collectively, present data suggest that resveratrol does not affect life span, body composition, locomotor activity, stress response, and longevity-associated gene expression in w1118 D. melanogaster.

Composition and method for solution mining of uranium ores

International Nuclear Information System (INIS)

Lawes, B.C.; Watts, J.C.

1981-01-01

It has been found that, in the solution mining of uranium ores using ammonium carbonate solutions containing hydrogen peroxide or ozone as an oxidant, the tendency of the formation being treated to become less permeable during the leaching process can be overcome by including in the leaching solution a very small concentration of sodium silicate

A new method of accurate determination of isotopic composition and concentration of strontium in a spike solution used for geochronological works

International Nuclear Information System (INIS)

Yanagi, Takeru

1990-01-01

A new method of accurate determination of isotopic composition and concentration of a strontium-84 spike solution was devised for simultaneous determination of strontium contents and isotopic compositions in rocks and minerals by measuring strontium isotopic ratios in spiked samples. In this method, the isotopic composition of strontium in the spike were determined so as to minimize the sum of squares of deviations of spike strontium-84 concentrations which were calculated from measured isotopic ratios of strontium in five different mixtures of the spike and the standard solution. The method can eliminate all mass discriminations occurred during the measurements on a surface ionization mass spectrometer. The results were tested by measuring 87 Sr/ 86 Sr ratios of Eimer and Amend SrCO 3 and JB-1 geochemical reference material, and by determining the strontium content in JB-1. The measurements of strontium isotope ratios in spiked samples give average values of 0.708007±0.000052 and 0.70417±0.00004 for 87 Sr/ 86 Sr ratios of E and A SrCO 3 and JB-1, respectively. The strontium content in JB-1 was estimated at 457.1±1.3 ppm. These values are very close to reported respective values. (author)

Chemical composition of the humus layer, mineral soil and soil solution of 200 forest stands in the Netherlands in 1995

NARCIS (Netherlands)

Leeters, E.E.J.M.; Vries, de W.

2001-01-01

A nationwide assessment of the chemical composition of the soil solid phase and the soil solution in the humus layer and two mineral layers (0-10 cm and 10-30 cm) was made for 200 forest stands in the year 1995. The stands were part of the national forest inventory on vitality, included seven tree

Functional chitosan-based grapefruit seed extract composite films for applications in food packaging technology

International Nuclear Information System (INIS)

Tan, Y.M.; Lim, S.H.; Tay, B.Y.; Lee, M.W.; Thian, E.S.

2015-01-01

Highlights: • Chitosan-based grapefruit seed extract (GFSE) films were solution casted. • GFSE was uniformly dispersed within all chitosan film matrices. • All chitosan-based composite films showed remarkable transparency. • Increasing amounts of GFSE incorporated increased the elongation at break of films. • Chitosan-based GFSE composite films inhibited the proliferation of fungal growth. - Abstract: Chitosan-based composite films with different amounts of grapefruit seed extract (GFSE) (0.5, 1.0 and 1.5% v/v) were fabricated via solution casting technique. Experimental results showed that GFSE was uniformly dispersed within all chitosan film matrices. The presence of GFSE made the films more amorphous and tensile strength decreased, while elongation at break values increased as GFSE content increased. Results from the measurement of light transmission revealed that increasing amounts of GFSE (from 0.5 to 1.5% v/v) did not affect transparency of the films. Furthermore, packaging of bread samples with chitosan-based GFSE composite films inhibited the proliferation of fungal growth as compared to control samples. Hence, chitosan-based GFSE composite films have the potential to be a useful material in the area of food technology

Functional chitosan-based grapefruit seed extract composite films for applications in food packaging technology

Energy Technology Data Exchange (ETDEWEB)

Tan, Y.M. [Department of Mechanical Engineering, National University of Singapore (Singapore); Lim, S.H.; Tay, B.Y. [Forming Technology Group, Singapore Institute of Manufacturing Technology (Singapore); Lee, M.W. [Food Innovation and Resource Centre, Singapore Polytechnic (Singapore); Thian, E.S., E-mail: mpetes@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore (Singapore)

2015-09-15

Highlights: • Chitosan-based grapefruit seed extract (GFSE) films were solution casted. • GFSE was uniformly dispersed within all chitosan film matrices. • All chitosan-based composite films showed remarkable transparency. • Increasing amounts of GFSE incorporated increased the elongation at break of films. • Chitosan-based GFSE composite films inhibited the proliferation of fungal growth. - Abstract: Chitosan-based composite films with different amounts of grapefruit seed extract (GFSE) (0.5, 1.0 and 1.5% v/v) were fabricated via solution casting technique. Experimental results showed that GFSE was uniformly dispersed within all chitosan film matrices. The presence of GFSE made the films more amorphous and tensile strength decreased, while elongation at break values increased as GFSE content increased. Results from the measurement of light transmission revealed that increasing amounts of GFSE (from 0.5 to 1.5% v/v) did not affect transparency of the films. Furthermore, packaging of bread samples with chitosan-based GFSE composite films inhibited the proliferation of fungal growth as compared to control samples. Hence, chitosan-based GFSE composite films have the potential to be a useful material in the area of food technology.

Local composition shift of mixed working fluid in gas–liquid flow with phase transition

International Nuclear Information System (INIS)

Xu Xiongwen; Liu Jinping; Cao Le; Li Zeyu

2012-01-01

Local composition shift is an important characteristic of gas-liquid mixture flow with phase transition. It affects the heat transfer process, stream sonic velocity and the mixture distribution in the thermodynamic cycle. Presently, it is mainly calculated through the empirical models of the void fraction from pure fluid experiments. In this paper, we made efforts to obtain it and its rules basing on conservation equations derivation. The result calculated with propane/i-butane binary mixture was verified by the experiment in the evaporator of a refrigerator. As an extending, it was applied to a ternary mixture with components of methane, propane and butane and more information was presented and analyzed. The calculation approach presented in this paper can be applied any multicomponent mixture, and the rules will be helpful to improve the composition shift theory. - Highlights: ► Local composition shift of mixed working fluid in gas–liquid flow was modelled. ► A solution method for local composition of gas–liquid flow was proposed. ► The solution method was verified by the experimental result. ► Local composition shift mechanism of gas–liquid flow was studied

Investigation on synergism of composite additives for zinc corrosion inhibition in alkaline solution

Energy Technology Data Exchange (ETDEWEB)

Zhou Hebing [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), South China Normal University, Guangzhou 510006 (China); Huang Qiming; Liang Man; Lv Dongsheng; Xu Mengqing; Li Hong [Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), South China Normal University, Guangzhou 510006 (China); Li Weishan, E-mail: liwsh@scnu.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Engineering Research Center of Materials and Technology for Electrochemical Energy Storage (Ministry of Education), South China Normal University, Guangzhou 510006 (China)

2011-07-15

Highlights: {yields} An kind of environmentally benign organic composite additives is used firstly. {yields} The corrosion of zinc is inhibited used the organic compound as additive. {yields} The rate performance of the battery used the organic compound as additive is improved. {yields} The synergism of composite additives for zinc corrosion inhibition is investigated. - Abstract: The synergism of imidazole (IMZ) and poly(ethylene glycol) 600 (PEG) for zinc corrosion inhibition in 3 mol L{sup -1} KOH solution was investigated using a combination of electrochemical and gravimetric methods, and the surface morphology of the zinc was observed by scanning electron microscopy. It is found that there is a synergistic effect between IMZ and PEG for the zinc corrosion inhibition. The difference in molecular structure, ring for IMZ and chain for PEG, and in binding atoms with zinc, nitrogen in IMZ and oxygen in PEG, contributes to this synergistic effect. IMZ inhibits zinc corrosion by mainly depressing the anodic reaction, whereas PEG by depressing the cathodic reaction. The storage performance of the zinc-manganese dioxide batteries using IMZ and/or PEG as inhibitors was determined by discharge test, with a comparison of the battery using mercury as the inhibitor. The battery containing 0.05% IMZ + 0.05% PEG exhibits better performance than the mercury-containing battery, especially when discharged at high rate.

Efficient removal of uranium from aqueous solution by zero-valent iron nanoparticle and its graphene composite

International Nuclear Information System (INIS)

Li, Zi-Jie; Wang, Lin; Yuan, Li-Yong; Xiao, Cheng-Liang; Mei, Lei; Zheng, Li-Rong; Zhang, Jing; Yang, Ju-Hua; Zhao, Yu-Liang; Zhu, Zhen-Tai; Chai, Zhi-Fang; Shi, Wei-Qun

2015-01-01

Highlights: • Uranium removal by ZVI-nps: independent of pH, the presence of CO 3 2− , humic acid, or mimic groundwater constituents. • Rapid removal kinetics and sorption capacity of ZVI-nps is 8173 mg U/g. • Two reaction mechanisms: sufficient Fe 0 → reductive precipitation as U 3 O 7 ; insufficient Fe 0 → hydrolysis precipitation of U(VI). • Fe/graphene composites: improved kinetics and higher U(VI) reduction ratio. - Abstract: Zero-valent iron nanoparticle (ZVI-np) and its graphene composites were prepared and applied in the removal of uranium under anoxic conditions. It was found that solutions containing 24 ppm U(VI) could be completely cleaned up by ZVI-nps, regardless of the presence of NaHCO 3 , humic acid, mimic groundwater constituents or the change of solution pH from 5 to 9, manifesting the promising potential of this reactive material in permeable reactive barrier (PRB) to remediate uranium-contaminated groundwater. In the measurement of maximum sorption capacity, removal efficiency of uranium kept at 100% until C 0 (U) = 643 ppm, and the saturation sorption of 8173 mg U/g ZVI-nps was achieved at C 0 (U) = 714 ppm. In addition, reaction mechanisms were clarified based on the results of SEM, XRD, XANES, and chemical leaching in (NH 4 ) 2 CO 3 solution. Partially reductive precipitation of U(VI) as U 3 O 7 was prevalent when sufficient iron was available; nevertheless, hydrolysis precipitation of U(VI) on surface would be predominant as iron got insufficient, characterized by releases of Fe 2+ ions. The dissolution of Fe 0 cores was assigned to be the driving force of continuous formation of U(VI) (hydr)oxide. The incorporation of graphene supporting matrix was found to facilitate faster removal rate and higher U(VI) reduction ratio, thus benefitting the long-term immobilization of uranium in geochemical environment

A Local Composition Model for Paraffinic Solid Solutions

DEFF Research Database (Denmark)

Coutinho, A.P. João; Knudsen, Kim; Andersen, Simon Ivar

1996-01-01

The description of the solid-phase non-ideality remains the main obstacle in modelling the solid-liquid equilibrium of hydrocarbons. A theoretical model, based on the local composition concept, is developed for the orthorhombic phase of n-alkanes and tested against experimental data for binary sy...... systems. It is shown that it can adequately predict the experimental phase behaviour of paraffinic mixtures. This work extends the applicability of local composition models to the solid phase. Copyright (C) 1996 Elsevier Science Ltd....

Development and Characterization of Sr-Containing Glass-Ceramic Composites Based on Biogenic Hydroxyapatite

Science.gov (United States)

Kuda, Oleksii; Pinchuk, Nataliia; Bykov, Oleksandr; Tomila, Tamara; Olifan, Olena; Golovkova, Maryna

2018-05-01

Composite materials based on hydroxyapatite are widely used for bone tissue engineering. There is evidence of a positive effect of the presence of strontium in osteoplastic materials in the case of a Ca/Sr certain ratio. To examine the effect of the addition of Sr2+, a study was made by introducing it into the material composition based on biogenic hydroxyapatite and sodium borosilicate glass (50/50% wt.). The strontium was introduced into the composition in an amount of 1% wt. Composite materials were obtained at final sintering temperatures of 780 °C and a sintering time of 1 h. The effect of additions of glass phase and strontium affect changes in the crystal lattice of biogenic hydroxyapatite was investigated with the help of X-ray phase analysis, IR spectroscopy. Also the behavior of composites in vitro in physiological solution was studied.

Ant-mediated effects on spruce litter decomposition, solution chemistry, and microbial activity

DEFF Research Database (Denmark)

Stadler, B.; Schramm, Andreas; Kalbitz, K.

2006-01-01

the effects of ants and aphid honeydew on litter solution of Norway spruce, microbial enzyme activities, and needle decomposition in a field and greenhouse experiment during summer 2003. In the field, low ant densities had relatively little effects on litter solution 30 cm away from a tree trunk...... and %N were not affected by ants or honeydew. Our results suggest that ants have a distinct and immediate effect on solution composition and microbial activity in the litter layer indicating accelerated litter decay whereas the effect of honeydew was insignificant. Keywords: Ants; Decomposition; Formica......Forest management practices often generate clear-cut patches, which may be colonized by ants not present in the same densities in mature forests. In addition to the associated changes in abiotic conditions ants can initiate processes, which do not occur in old-growth stands. Here, we analyse...

Literature survey on phase composition of hardened cement paste containing fly ash

International Nuclear Information System (INIS)

Otsuka, Taku; Yamamoto, Takeshi

2015-01-01

The purpose of this literature survey is to collect the knowledge on the effect of fly ash in hardened cement paste and the information about evaluation of physicochemical performance based on phase composition of hardened cement paste. The performance of hardened cement paste containing fly ash is affected by the property of fly ash, hydration of cement and pozzolanic reaction of fly ash. Some properties of fly ash such as density and chemical composition are reflected in phase composition, showing the progress of cement hydration and pozzolanic reaction. Therefore clarification of the relationship of phase composition and performance will lead to appropriate evaluation of the property of fly ash. The amount of pore, chemical shrinkage, pore solution, compressive strength, Young modulus and alkali silica reaction have relations to the phase composition of hardened cement paste. It is considered as future subject to clarify the relationship of phase composition and performance for various properties of fly ash. (author)

Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

Directory of Open Access Journals (Sweden)

Carlos Gumiel

2018-01-01

Full Text Available Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600 °C.

Thin film composites in the BiFeO3–Bi4Ti3O12 system obtained by an aqueous solution-gel deposition methodology

International Nuclear Information System (INIS)

Gumiel, C.; Vranken, T.; Bernardo, M.S.; Jardiel, T.; Hardy, A.; Van Bael, M.K.; Peiteado, M.

2018-01-01

Thin film multiferroic composites, with a high quantity of interfaces between the different materials, represent a more feasible alternative to single phase systems in which the multifunctional response is usually hampered due to intrinsic physical constraints. Nowadays some of these composites can be produced by applying deposition techniques such as PLD, CVD, MBE or the like, which allow a high degree of crystallographic control. However, despite their effectiveness, all these techniques also involve a high consumption of energy in terms of temperature and/or vacuum. Within this frame, the present contribution proposes a sustainable chemical solution deposition process to prepare thin films of the multiferroic BiFeO3–Bi4Ti3O12 composite system. More specifically an aqueous solution-gel plus spin-coating methodology is employed which also avoids the organic solvents typically used in a conventional sol–gel method, so further keeping an eye on the environmentally friendly conditions. Attempts are conducted that demonstrate how by systematically controlling the processing parameters it is possible to obtain thin film composites with a promising 3-3 type connectivity at temperatures as low as 600°C. [es

The Development, Implementation, and Evaluation of a Model for Teaching Composition Which Utilizes Gestalt Therapy Techniques.

Science.gov (United States)

Tixier, Linda

As a solution to the problems presented by approaches to teaching English composition that are almost purely cognitive in nature, an experimental course was offered for freshmen at the Miami-Dade Community College. The course was designed to be holistic and confluent, synthesizing both the cognitive and affective domains by incorporating Gestalt…

Metals other than uranium affected microbial community composition in a historical uranium-mining site.

Science.gov (United States)

Sitte, Jana; Löffler, Sylvia; Burkhardt, Eva-Maria; Goldfarb, Katherine C; Büchel, Georg; Hazen, Terry C; Küsel, Kirsten

2015-12-01

To understand the links between the long-term impact of uranium and other metals on microbial community composition, ground- and surface water-influenced soils varying greatly in uranium and metal concentrations were investigated at the former uranium-mining district in Ronneburg, Germany. A soil-based 16S PhyloChip approach revealed 2358 bacterial and 35 archaeal operational taxonomic units (OTU) within diverse phylogenetic groups with higher OTU numbers than at other uranium-contaminated sites, e.g., at Oak Ridge. Iron- and sulfate-reducing bacteria (FeRB and SRB), which have the potential to attenuate uranium and other metals by the enzymatic and/or abiotic reduction of metal ions, were found at all sites. Although soil concentrations of solid-phase uranium were high, ranging from 5 to 1569 μg·g (dry weight) soil(-1), redundancy analysis (RDA) and forward selection indicated that neither total nor bio-available uranium concentrations contributed significantly to the observed OTU distribution. Instead, microbial community composition appeared to be influenced more by redox potential. Bacterial communities were also influenced by bio-available manganese and total cobalt and cadmium concentrations. Bio-available cadmium impacted FeRB distribution while bio-available manganese and copper as well as solid-phase zinc concentrations in the soil affected SRB composition. Archaeal communities were influenced by the bio-available lead as well as total zinc and cobalt concentrations. These results suggest that (i) microbial richness was not impacted by heavy metals and radionuclides and that (ii) redox potential and secondary metal contaminants had the strongest effect on microbial community composition, as opposed to uranium, the primary source of contamination.

Sorption of technetium on composite chitosan-hydroxyapatite from aqueous solutions

International Nuclear Information System (INIS)

Pivarciova, L.; Rosskopfova, O.; Galambos, M.; Rajec, P.

2013-01-01

Biomaterials such as natural polymers (chitosan) and hydroxyapatite have an important application in material for bone replacement. Most of chitosan/hydroxyapatite composites are prepared by mixing hydroxyapatite particles with chitosan matrices. Another method of preparation of chitosan/hydroxyapatite composite is in-situ generation of nano-hydroxyapatite in chitosan matrix. The most common biomaterial used in the past years in hard tissue regeneration was hydroxyapatite, owing to its properties as biocompatibility, bioactivity, non-toxicity, non-immunogenicity etc. Chitosan is a polyaminosacharide, partially deacetylated product of chitin. Chitosan can be used in combination with other materials to enhance bone growth such as bone filling paste. The aims of this work were: the influence of the contact time on sorption of pertechnate anions on chitosan/hydroxyapatite composites; the effect of pH on sorption of pertechnate anions on chitosan/hydroxyapatite composites; the effect of foreign ions on sorption of pertechnate anions on chitosan/hydroxyapatite composites. The author concluded: the percentage of technetium sorption after 1 hour of contact time was > 97 %. In the initial pH range of 2.9-10.2, the percentage of technetium sorption on chitosan/hydroxyapatite composites CH/HA(A), CH/HA(B), CH/HA 30:70, ZCH was > 98 % and on CH/HA 50:50 was > 94%. The competition effect of Fe 2+ towards TcO 4 :- sorption is stronger than competition effect of other observed cations for all examined composites with the same weight ratio. The percentage of the technetium sorption was the same for all composites with the weight ratio of 30:70. (authors)

Zn availability in nutrient solutions for cucumber (Cucumis sativus L) in hydroponics as affected by Fe-chelates and pH

NARCIS (Netherlands)

Voogt, W.; Sonneveld, C.

2017-01-01

In soil-less culture systems Fe is usually supplied as chelate to ensure an adequate availability of this element. As chelates have affinity for many metal ions these chelates will interact with other cation nutrients in nutrient solutions. This affects the availability of Fe and other nutrients.

Electrochemical lithiation performance and characterization of silicon-graphite composites with lithium, sodium, potassium, and ammonium polyacrylate binders.

Science.gov (United States)

Han, Zhen-Ji; Yamagiwa, Kiyofumi; Yabuuchi, Naoaki; Son, Jin-Young; Cui, Yi-Tao; Oji, Hiroshi; Kogure, Akinori; Harada, Takahiro; Ishikawa, Sumihisa; Aoki, Yasuhito; Komaba, Shinichi

2015-02-07

Poly(acrylic acid) (PAH), which is a water soluble polycarboxylic acid, is neutralized by adding different amounts of LiOH, NaOH, KOH, and ammonia (NH4OH) aqueous solutions to fix neutralization degrees. The differently neutralized polyacid, alkali and ammonium polyacrylates are examined as polymeric binders for the preparation of Si-graphite composite electrodes as negative electrodes for Li-ion batteries. The electrode performance of the Si-graphite composite depends on the alkali chemicals and neutralization degree. It is found that 80% NaOH-neutralized polyacrylate binder (a pH value of the resultant aqueous solution is ca. 6.7) is the most efficient binder to enhance the electrochemical lithiation and de-lithiation performance of the Si-graphite composite electrode compared to that of conventional PVdF and the other binders used in this study. The optimum polyacrylate binder highly improves the dispersion of active material in the composite electrode. The binder also provides the strong adhesion, suitable porosity, and hardness for the composite electrode with 10% (m/m) binder content, resulting in better electrochemical reversibility. From these results, the factors of alkali-neutralized polyacrylate binders affecting the electrode performance of Si-graphite composite electrodes are discussed.

Amino acid composition of soybean seeds as affected by climatic variables

Directory of Open Access Journals (Sweden)

Constanza Soledad Carrera

2011-12-01

Full Text Available The objective of this work was to perform a quantitative analysis of the amino acid composition of soybean seeds as affected by climatic variables during seed filling. Amino acids were determined from seed samples taken at harvest in 31 multi-environment field trials carried out in Argentina. Total amino acids ranged from 31.69 to 49.14%, and total essential and nonessential amino acids varied from 12.83 to 19.02% and from 18.86 to 31.15%, respectively. Variance components expressed as the percentage of total variation showed that the environment was the most important source of variation for all traits, followed by the genotype x environment interaction. Significant explanatory linear regressions were detected for amino acid content regarding: average daily mean air temperature and cumulative solar radiation, during seed filling; precipitation minus potential evapotranspiration, during the whole reproductive period; and the combinations of these climatic variables. Each amino acid behaves differently according to environmental conditions, indicating compensatory effects among them.

Evaluating the effect of administrating hypertonic and isotonic saline solutions on clinical improvement, serum electrolyte concentrations and renal function of calves affected by diarrhea

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A Hasanpour

2009-11-01

This study was conducted on 40 calves under the age of one mouth with 30 calves affected by diarrhea allocated to 3 treatment groups of 10 calves each and the control group consisting of 10 calves. The control group received neither treatment nor any injections. In the first treatment group, only antibiotics were administered without any fluid therapy. In the second treatment group, apart from antibiotic therapy of diarrhea, hypertonic saline solution (7.5% was administered at a dose of 5 ml/kg as slow intravenous infusion alongside oral ORS solution whereas in the third treatment group isotonic saline solution (0.9% was given intravenously according to the formula (Body weight × %Dehydration alongside oral ORS solution. In all groups, clinical examination and blood sampling was undertaken at times 0, 1, 2, 8 and 24 hours following treatment. At time 0, the diarrhea had resulted in clinical and laboratory signs such as a fever, the dehydration, tachycardia, oligopnea, increased packed sell volume, hypernatremia, hyperchloremia, hyperkalemia, hyperphosphatemia, hypercalcemia, increased serum creatinine and BUN values. Following treatment, fever subsided and the dehydration was corrected and this correction occurred faster in calves which had received hypertonic saline solution. Correction of sodium, potassium, chloride, phosphorus and calsium imbalance occurred faster in patients which were treated by hypertonic solution. Fluid therapy with saline solutions prevented the increase in serum creatinine and BUN values. In conclusion, the administration of hypertonic saline solutions leads to much faster and more reliable clinical improvement and electrolyte imbalance correction in calves affected by diarrhea.

Potentiometric titration for determining the composition and stability of metal(II) alginates and pectinates in aqueous solutions

Science.gov (United States)

Kaisheva, N. Sh.; Kaishev, A. Sh.

2015-07-01

The compositions and stabilities of Cu2+, Mn2+, Pb2+, Ca2+, Zn2+, Cd2+, Co2+, and Ni2+ alginates and pectinates are determined in aqueous solutions via titrimetry and potentiometry with calculations performed using Bjerrum's method, the curve intersection technique, and the equilibrium shift method. It is found that the interaction between Cu2+ and polyuronides is a stepwise process and, depending on the ligand concentration and the method of determination, Cu2+ alginate can be characterized by its ML, ML2, and ML3 compositions (where M is the metal ion and L is the structural unit of polyuronide) and stability constants logβ = 2.65, 5.00-5.70, and 7.18-7.80, respectively. The compositions of Cu2+ pectinates are ML and ML2 with logβ = 3.00 and 7.64-7.94, respectively. It is concluded that Pb2+, Ca2+, Mn2+, Zn2+, Cd2+, Co2+, and Ni2+ ions form only alginates and pectinates of ML2 composition with logβ values of 3.45 (Pb2+ alginate), 2.20 (Ca2+ alginate), 1.06 (Mn2+ alginate), 3.51 (Pb2+ pectinate), 2.35 (Ca2+ pectinate), and 1.24 (Mn2+ pectinate). The pectinates are shown to be more stable than the alginates, the most stable compounds being those formed by polyuronides and Cu2+. The least stable are those with Mn2+.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

Statics and rotational dynamics of composite beams

CERN Document Server

Ghorashi, Mehrdaad

2016-01-01

This book presents a comprehensive study of the nonlinear statics and dynamics of composite beams and consists of solutions with and without active elements embedded in the beams. The static solution provides the initial conditions for the dynamic analysis. The dynamic problems considered include the analyses of clamped (hingeless) and articulated (hinged) accelerating rotating beams. Two independent numerical solutions for the steady state and the transient responses are presented. The author illustrates that the transient solution of the nonlinear formulation of accelerating rotating beam converges to the steady state solution obtained by the shooting method. Other key areas considered include calculation of the effect of perturbing the steady state solution, coupled nonlinear flap-lag dynamics of a rotating articulated beam with hinge offset and aerodynamic damping, and static and dynamic responses of nonlinear composite beams with embedded anisotropic piezo-composite actuators. The book is intended as a t...

Dietary conjugated linoleic acids affect tissue lipid composition but not de novo lipogenesis in finishing pigs

OpenAIRE

Bee , Giuseppe

2001-01-01

International audience; Dietary conjugated linoleic acids (CLA) have been reported to profoundly affect lipid metabolism and to act as repartitioning agents. Currently, little is known about their effect on the fatty acid profile of tissue lipids in pigs. In the present study we determined the lipid composition of the backfat inner (BFI) and outer layer (BFO), omental fat (OF) and intramuscular fat (IMF) of the longissimus dorsi muscle in 24 Swiss Large White pigs fed diets supplemented eithe...

Investigation of antimony extraction from nitric acid solutions by tributyl phosphate

International Nuclear Information System (INIS)

Lakaev, V.S.; Smelov, V.S.

1988-01-01

The effect of iodide, hydrogen and pertechnetate ions on antimony extraction by tri-n-butyl phosphate (TBP) from aqueous nitric acid solutions under irradiated nuclear fuel processing is investigated at room temperature. The coefficients of antimony distribution are shown to increase at the presence of technetium ions 2-3 times and iodine ions - 100 and more times. Variation of hydrogen ion concentration does not affect antimony extraction. The schemes of the mechanism of antimony extraction at the pressence of iodide and pertechnetate ions are presented. Compositions of the formed compounds are given

Extremophiles in Mineral Sulphide Heaps: Some Bacterial Responses to Variable Temperature, Acidity and Solution Composition

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Helen R. Watling

2015-07-01

Full Text Available In heap bioleaching, acidophilic extremophiles contribute to enhanced metal extraction from mineral sulphides through the oxidation of Fe(II and/or reduced inorganic sulphur compounds (RISC, such as elemental sulphur or mineral sulphides, or the degradation of organic compounds derived from the ore, biota or reagents used during mineral processing. The impacts of variable solution acidity and composition, as well as temperature on the three microbiological functions have been examined for up to four bacterial species found in mineral sulphide heaps. The results indicate that bacteria adapt to sufficiently high metal concentrations (Cu, Ni, Co, Zn, As to allow them to function in mineral sulphide heaps and, by engaging alternative metabolic pathways, to extend the solution pH range over which growth is sustained. Fluctuating temperatures during start up in sulphide heaps pose the greatest threat to efficient bacterial colonisation. The large masses of ores in bioleaching heaps mean that high temperatures arising from sulphide oxidation are hard to control initially, when the sulphide content of the ore is greatest. During that period, mesophilic and moderately thermophilic bacteria are markedly reduced in both numbers and activity.

Kevlar reinforced neoprene composites

Science.gov (United States)

Penn, B. G.; Daniels, J. G.; White, W. T.; Thompson, L. M.; Clemons, L. M.

1985-01-01

Kevlar/neoprene composites were prepared by two techniques. One method involved the fabrication of a composite from a rubber prepreg prepared by coating Kevlar with viscous neoprene solution and then allowing the solvent to evaporate (solution impregnation technique). The second method involved heating a stack of Kevlar/neoprene sheets at a temperature sufficient to cause polymer flow (melt flow technique). There was no significant difference in the breaking strength and percent elongation for samples obtained by the two methods; however the shear strength obtained for samples fabricated by the solution impregnation technique (275 psi) was significantly higher than that found for the melt flow fabricated samples (110 psi).

Antibiotic Treatment Affects Intestinal Permeability and Gut Microbial Composition in Wistar Rats Dependent on Antibiotic Class.

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Monica Vera-Lise Tulstrup

Full Text Available Antibiotics are frequently administered orally to treat bacterial infections not necessarily related to the gastrointestinal system. This has adverse effects on the commensal gut microbial community, as it disrupts the intricate balance between specific bacterial groups within this ecosystem, potentially leading to dysbiosis. We hypothesized that modulation of community composition and function induced by antibiotics affects intestinal integrity depending on the antibiotic administered. To address this a total of 60 Wistar rats (housed in pairs with 6 cages per group were dosed by oral gavage with either amoxicillin (AMX, cefotaxime (CTX, vancomycin (VAN, metronidazole (MTZ, or water (CON daily for 10-11 days. Bacterial composition, alpha diversity and caecum short chain fatty acid levels were significantly affected by AMX, CTX and VAN, and varied among antibiotic treatments. A general decrease in diversity and an increase in the relative abundance of Proteobacteria was observed for all three antibiotics. Additionally, the relative abundance of Bifidobacteriaceae was increased in the CTX group and both Lactobacillaceae and Verrucomicrobiaceae were increased in the VAN group compared to the CON group. No changes in microbiota composition or function were observed following MTZ treatment. Intestinal permeability to 4 kDa FITC-dextran decreased after CTX and VAN treatment and increased following MTZ treatment. Plasma haptoglobin levels were increased by both AMX and CTX but no changes in expression of host tight junction genes were found in any treatment group. A strong correlation between the level of caecal succinate, the relative abundance of Clostridiaceae 1 family in the caecum, and the level of acute phase protein haptoglobin in blood plasma was observed. In conclusion, antibiotic-induced changes in microbiota may be linked to alterations in intestinal permeability, although the specific interactions remain to be elucidated as changes in

Electrodialysis potential for fractionation of multicomponent aqueous solutions

Science.gov (United States)

Grzegorzek, Martyna; Majewska-Nowak, Katarzyna

2017-11-01

The paper aimed at the evaluation of the batch electrodialysis (ED) run in the course of treatment and desalination of various aqueous mixtures containing both mineral (sodium fluoride, sodium chloride) and organic substances (dyes or humic acids). The commercial ED stack (PCCell Bed) equipped with standard anion-exchange and cation-exchange membranes or monovalent selective anion-exchange membranes was used. The ED experiments were performed at a constant current density (1.56 or 1.72 mA/cm2). The mechanism of ion migration as well as membrane deposition for variable solution composition and various membrane types was analyzed The calculated mass balance and electrical energy demand for each ED run were helpful in evaluating the membrane fouling intensity. It was found that the presence of organic substances in the treated solution had a minor impact on energy consumption, but rather strongly affected chloride flux. The extent of organics deposition was significantly lower for monovalent selective anion-exchange membranes than for classic anion-exchange membranes.

Evaluating interfacial shear stresses in composite hollo

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Aiham Adawi

2016-09-01

Full Text Available Analytical evaluation of the interfacial shear stresses for composite hollowcore slabs with concrete topping is rare in the literature. Adawi et al. (2014 estimated the interfacial shear stiffness coefficient (ks that governs the behavior of the interface between hollowcore slabs and the concrete topping using push-off tests. This parameter is utilized in this paper to provide closed form solutions for the differential equations governing the behavior of simply supported composite hollowcore slabs. An analytical solution based on the deformation compatibility of the composite section and elastic beam theory, is developed to evaluate the shear stresses along the interface. Linear finite element modeling of the full-scale tests presented in Adawi et al. (2015 is also conducted to validate the developed analytical solution. The proposed analytical solution was found to be adequate in estimating the magnitude of horizontal shear stress in the studied composite hollowcore slabs.

VARIATIONS IN MATERNAL DIETARY FATTY ACID COMPOSITION AFFECTS THE NEURODEVELOPMENT OF RAT PUPS.

Directory of Open Access Journals (Sweden)

2017-01-01

Full Text Available Fatty acids are part of the structural matrix of cellular and subcellular membranes. Alterations in tissue fatty acid composition can affect nerve tissue function by altering membrane thickness or by changing properties of the lipid phase. In this study, the appearance of specific neurodevelopment responses was observed on rap pups whose dams were fed on varied dietary fatty acid composition. Three dietary treatments of corn oil, fish oil and reference meals were administered on these groups of pregnant dams. From postnatal day 5 to 30, littered pups were assessed daily for the appearance of neurodevelopmental reflexes based on the Smart- Dobbing method. The neurodevelopmental attributes of Righting reflex, Cliff avoidance, Negative geotaxis, Auditory startle, Vibrissa placing, Free-fall righting and Visual placing was observed in experimental pups between day 5 and 30. Tests were conducted between 1200 and 1400h. A 30 seconds time limit was employed in testing of the cliff-avoidance and negative-geotaxis appearance. The time appearance of auditory-startle and vibrissa-placing responses were significantly delayed (P and lt;0.05 in pups of dietary fish oil and ndash; fed dams than those of corn oil fed dams. The delay in auditory-startle response may be due to negative myelination of the auditory brainstem pathway.

Y2O3-MgO Nano-Composite Synthesized by Plasma Spraying and Thermal Decomposition of Solution Precursors

Science.gov (United States)

Muoto, Chigozie Kenechukwu

This research aims to identify the key feedstock characteristics and processing conditions to produce Y2O3-MgO composite coatings with high density and hardness using solution precursor plasma spray (SPPS) and suspension plasma spray (SPS) processes, and also, to explore the phenomena involved in the production of homogenized nano-composite powders of this material system by thermal decomposition of solution precursor mixtures. The material system would find potential application in the fabrication of components for optical applications such as transparent windows. It was shown that a lack of major endothermic events during precursor decomposition and the resultant formation of highly dense particles upon pyrolysis are critical precursor characteristics for the deposition of dense and hard Y2O3-MgO coatings by SPPS. Using these principles, a new Y2O3-MgO precursor solution was developed, which yielded a coating with Vickers hardness of 560 Hv. This was a considerable improvement over the hardness of the coatings obtained using conventional solution precursors, which was as low as 110 Hv. In the thermal decomposition synthesis process, binary solution precursor mixtures of: yttrium nitrate (Y[n]) or yttrium acetate (Y[a]), with magnesium nitrate (Mg[n]) or magnesium acetate (Mg[a]) were used in order to study the effects of precursor chemistry on the structural characteristics of the resultant Y2O3-MgO powders. The phase domains were coarse and distributed rather inhomogeneously in the materials obtained from the Y[n]Mg[n] and Y[a]Mg[a] mixtures; finer and more homogeneously-distributed phase domains were obtained for ceramics produced from the Y[a]Mg[n] and Y[n]Mg[a] mixtures. It was established that these phenomena were related to the thermal characteristics for the decomposition of the precursors and their effect on phase separation during oxide crystallization. Addition of ammonium acetate to the Y[n[Mg[n] mixture changed the endothermic process to exothermic

Composition of human skin microbiota affects attractiveness to malaria mosquitoes.

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Niels O Verhulst

Full Text Available The African malaria mosquito Anopheles gambiae sensu stricto continues to play an important role in malaria transmission, which is aggravated by its high degree of anthropophily, making it among the foremost vectors of this disease. In the current study we set out to unravel the strong association between this mosquito species and human beings, as it is determined by odorant cues derived from the human skin. Microbial communities on the skin play key roles in the production of human body odour. We demonstrate that the composition of the skin microbiota affects the degree of attractiveness of human beings to this mosquito species. Bacterial plate counts and 16S rRNA sequencing revealed that individuals that are highly attractive to An. gambiae s.s. have a significantly higher abundance, but lower diversity of bacteria on their skin than individuals that are poorly attractive. Bacterial genera that are correlated with the relative degree of attractiveness to mosquitoes were identified. The discovery of the connection between skin microbial populations and attractiveness to mosquitoes may lead to the development of new mosquito attractants and personalized methods for protection against vectors of malaria and other infectious diseases.

Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

International Nuclear Information System (INIS)

Riese, A.C.; Propp, C.J.

1980-01-01

Modern methods of uranium solution mining are typically accompanied by gains and losses of mass through reagent consumption by rock-forming minerals, with subsequent formation of clay minerals, gypsum, carbonates, and iron oxyhydroxides. A systematic approach to alleviate such problems involves the application of leach solutions that are in equilibrium with the host-rock minerals but in disequilibrium with the ore-forming minerals. This partial equilibrium can be approximated by solution-composition adjustments within the systems K 2 O-Al 2 O 3 SiO 2 -H 2 O and Na 2 O 3 -Al 2 O 3 SiO 2 -H 2 O. Uranium ore containing 0.15 percent U 3 O 8 from the Gulf Mineral Resources Corporation's Mariano Lake mine, the Smith Lake district of the Grants mineral belt, was collected for investigation. Presented are a theoretical evaluation of leachate data and an experimental treatment of the ore, which contained mainly K-feldspar, plagioclase feldspar, and quartz (with lesser amounts of micas, clay minerals, and organic carbonaceous material). Small-scale (less than or equal to 1 kg) column-leaching experiments were conducted to model the results of conventional leaching operations and to provide leachate solutions that could be compared with solutions calculated to be in equilibrium with the matrix minerals. Leach solutions employed include: 1) sulfuric acid, 2) sodium bicarbonate, and 3) sulfuric acid with 1.0 molal potassium chloride. The uranium concentrations in the sodium-bicarbonate leach solution and the acid-leach solution were about a gram per liter at the termination of the tests. However, the permeability of the ore in the acid leach was greatly reduced, owing to the formation of clay minerals. Uranium solubility in the leach column stabilized with the potassium-chloride solution was calculated from leachate compositions to be limited by the solubility of carnotite

Application of composite materials based on various extractants for isolation of lanthanides(III) nitrates from multicomponent aqueous solutions

International Nuclear Information System (INIS)

Kopyrin, A.A.; Pyartman, A.K.; Kesnikov, V.A.; Pleshkov, M.A.; Exekov, M.H.

1999-01-01

In present work we obtained samples of composite materials mentioned containing tributylphosphate (TBP) and trialkylmethylammonium nitrate (TAMAN). Extraction of lanthanides(III) nitrates of cerium group from multicomponent aqueous solutions by means of these materials was studied. Some systems with different concentration of sodium nitrate up to 5 mol/l and the same systems containing additions of sodium chloride or sulfate along with sodium nitrate was investigated, isotherm of extraction being obtained for all cases. Also we compared in identical conditions extraction process when liquid extractants were used and process with composite materials. It was found that traditional extraction systems and systems based on composite extractants demonstrated almost the same extraction properties in respect to lanthanides(III) nitrates. Extraction isotherms observed in identical conditions and being shown in the same coordinates had no difference with taking into account errors of experiment. This fact allow to use the same mathematical model for those systems. For systems studied it was generated mathematical model that is able to describe extraction process when component concentration vary in wide range, with assumption being used that ratio activity coefficients in organic phase stay constant. (authors)

Solution behavior of metoclopramide in aqueous-alcoholic solutions at 30°C

Science.gov (United States)

Deosarkar, S. D.; Sawale, R. T.; Tawde, P. D.; Kalyankar, T. M.

2016-07-01

Densities (ρ) and refractive indices ( n D) of solutions of antiemetic drug metoclopramide (4-amino-5-chloro- N-(2-(diethylamino)ethyl)-2-methoxybenzamide hydrochloride hydrate) in methanolwater and ethanol-water mixtures of different compositions were measured at 30°C. Apparent molar volume (φv) of the drug was calculated from density data and partial molar volumes (φ v 0 ) were determined from Massons relation. Concentration dependence of nD has been studied to determine refractive indices of solution at infinite dilution ( n D 0 ). Results have been interpreted in terms of solute-solvent interactions.

Response surface methodology for the optimization of lanthanum removal from an aqueous solution using a Fe{sub 3}O{sub 4}/chitosan nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Haldorai, Yuvaraj [Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul (Korea, Republic of); Rengaraj, Arunkumar [Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon 402-751 (Korea, Republic of); Ryu, Taegong; Shin, Junho [Mineral Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Huh, Yun Suk, E-mail: yunsuk.huh0311@gmail.com [Department of Biological Engineering, Biohybrid Systems Research Center (BSRC), Inha University, Incheon 402-751 (Korea, Republic of); Han, Young-Kyu, E-mail: ykenergy@dongguk.edu [Department of Energy and Materials Engineering, Dongguk University-Seoul, Seoul (Korea, Republic of)

2015-05-15

Highlights: • Magnetite/chitosan composite for lanthanum removal. • Response surface methodology was used for optimization. • A 99.88% removal of La{sup 3+} was observed at 40 °C, pH 11, and 50 min. • Adsorption process was significantly affected by pH and adsorbent dosage. • Biocompatible, eco-friendly and a low-cost adsorbent. - Abstract: In the present work, magnetite nanoparticles/chitosan composites (Fe{sub 3}O{sub 4}/CS) were prepared by a chemical precipitation method. We demonstrated the efficient removal of a rare earth metal, lanthanum (La{sup 3+}), from an aqueous solution using the composite. The removal of La{sup 3+} was optimized by using response surface methodology. Analysis of variance and Fisher's F-test were used to determine the reaction parameters which affect the removal of La{sup 3+}. Optimal conditions, including adsorbent dosage, pH, temperature, and contact time for the removal of La{sup 3+}, were found to be 6.5 mg, pH 11, 40 °C, and 50 min, respectively. The adsorption capacity was 99.88%. The rate of La{sup 3+} adsorption was significantly affected by the solution pH and adsorbent amount. An adsorption isotherm was fitted well by the Freundlich model with a linear regression correlation value of 0.9975. The adsorption of La{sup 3+} using the composite followed pseudo second-order kinetics. Thermodynamic studies have revealed that the negative values of Gibbs free energy confirmed the spontaneous and feasible nature of adsorption.

The effect of pH on phosphorus availability and speciation in an aquaponics nutrient solution.

Science.gov (United States)

Cerozi, Brunno da Silva; Fitzsimmons, Kevin

2016-11-01

The interaction between the main ions in aquaponics nutrient solutions affects chemical composition and availability of nutrients, and nutrient uptake by plant roots. This study determined the effect of pH on phosphorus (P) speciation and availability in an aquaponics nutrient solution and used Visual MINTEQ to simulate P species and P activity. In both experimental and simulated results, P availability decreased with increase in pH of aquaponics nutrient solutions. According to simulations, P binds to several cations leaving less free phosphate ions available in solution. High pH values resulted in the formation of insoluble calcium phosphate species. The study also demonstrated the importance of organic matter and alkalinity in keeping free phosphate ions in solution at high pH ranges. It is recommended though that pH in aquaponics systems is maintained at a 5.5-7.2 range for optimal availability and uptake by plants. Copyright © 2016 Elsevier Ltd. All rights reserved.

Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

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Shams Ali Baig

Full Text Available The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C and environment (air and nitrogen were investigated for the adsorptive removal of As(V and As(III from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4 via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2>Fe3O4-HBC (uncalcined>Fe3O4-HBC-400°C(N2>Fe3O4-HBC-400°C(air>Fe3O4-HBC-1000°C(air and the maximum As(V and As(III adsorption capacities were found to be about 3.35 mg g(-1 and 3.07 mg g(-1, respectively. The adsorption of As(V and As(III remained stable in a wider pH range (4-10 using Fe3O4-HBC-1000°C(N2. Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99 rather than pseudo-first-order kinetics model. The adsorption of As(V and As(III onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher strongly inhibited As(V and As(III removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

Science.gov (United States)

Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

2014-01-01

The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g(-1) and 3.07 mg g(-1), respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4-10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

Growth curve and diet density affect eating motivation, behavior, and body composition of broiler breeders during rearing.

Science.gov (United States)

de Los Mozos, J; García-Ruiz, A I; den Hartog, L A; Villamide, M J

2017-08-01

The aim of this work has been to assess the effect of diet density [control (CON) or 15% diluted (DIL)] and growth curve [recommended by the genetic line (RBW) or 15% heavier (HBW)] and their interaction on BW uniformity, feeding motivation, behavior, and body composition of broiler breeder pullets. A total of 3,000 one-day-old female breeders Ross 308, distributed in 20 pens, was randomly assigned to each treatment. Feed allowance was weekly adjusted to reach the desired BW. Feed was provided as pelleted (zero to 3 wk) and crumble (4 to 19 wk). Time eating was measured at 7, 11, and 19 weeks. A feeding rate test was performed after 11 weeks. Behavior was observed at 9 and 15 wk, by visual scan. At 6, 13, and 19 wk of age, one bird/pen was slaughtered for weighing different organs and analyzing the composition of empty whole bodies. Treatments did not affect BW uniformity; relative weights of the ovary, oviduct, or gizzard; or protein content of empty BW. Time eating varied with the growth curve at 19 wk (P motivation. Behavior was affected by the age and by the time of the d measured, but it did not change with the treatments. Birds spent most time pecking objects (50%), feeding (28%), and drinking (17%). Pullets fed DIL had 8% lower breast yield at different ages and higher empty digestive tracts at 6 weeks. Body composition varied with age; fat content increased from 12.7 to 15.9 to 19.8% for 6, 13, and 19 wk, respectively. The lowest body fat was observed for RBW pullets fed DIL (P = 0.003) at 19 weeks. Feeding DIL diets to HBW pullets could be done to increase the time spent eating and reduce their feeling of hunger without negative effects on body composition. However, its influence on behavior and BW uniformity was not proved. © The Author 2017. Published by Oxford University Press on behalf of Poultry Science Association.

Fuel effect on solution combustion synthesis of Co(Cr,Al)2O4 pigments

International Nuclear Information System (INIS)

Gilabert, J.; Palacios, M.D.; Sanz, V.; Mestre, S.

2017-01-01

The fuel effect on the synthesis of a ceramic pigment with a composition CoCr2−2ΨAl2ΨO4 (0≤Ψ≤1) by means of solution combustion synthesis process (SCS) has been studied. Three different fuels were selected to carry out the synthesis (urea, glycine and hexamethylentetramine (HMT)). Highly foamy pigments with very low density were obtained. Fd-3m spinel-type structure was obtained in all the experiments. Nevertheless, crystallinity and crystallite size of the spinels show significant differences with composition and fuel. The use of glycine along with the chromium-richest composition favours ion rearrangement to obtain the most ordered structure. Lattice parameter does not seem to be affected by fuel, although it evolves with Ψ according to Vegard's law. Colouring power in a transparent glaze shows important variations with composition. On the other hand, fuel effect presents a rather low influence since practically the same shades are obtained. However, it exerts certain effect on luminosity (L*). [es

Effects of different combinations of Hoagland's solution and Azolla ...

African Journals Online (AJOL)

ALAN

2013-04-17

Apr 17, 2013 ... hydroponic cultures containing different compositions of hydroponic solutions were evaluated in ... (Hoagland's solution minus N solution excluding Azolla; ..... nutrient deficiencies on photosynthesis and respiration in spinach.

Morphology and transport in biodegradable polymer compositions based on poly(3-hydroxybutyrate) and polyamide 54C

Energy Technology Data Exchange (ETDEWEB)

Zhul' kina, A. L.; Ivantsova, E. L.; Filatova, A. G.; Kosenko, R. Yu.; Gumargalieva, K. Z.; Iordanskii, A. L., E-mail: iordan@chph.ras.ru [Russian Academy of Sciences, Semenov Institute of Chemical Physics (Russian Federation)

2009-05-15

Complex investigation of the equilibrium sorption of water, diffusive transport of antiseptic, and morphology of mixed compositions based on polyoxybutirate and polyamide resin 54C has been performed to develop and analyze new biodegradable polymer compositions for controlled release of medicinal substances. Samples of mixtures were prepared by two methods: pressing under pressure and solvent evaporation from a polymer solution. The samples were compared and their morphology was analyzed by scanning electron microscopy. It is shown that the component ratio in the obtained mixtures affects their morphological, transport, and sorption characteristics.

Morphology and transport in biodegradable polymer compositions based on poly(3-hydroxybutyrate) and polyamide 54C

International Nuclear Information System (INIS)

Zhul'kina, A. L.; Ivantsova, E. L.; Filatova, A. G.; Kosenko, R. Yu.; Gumargalieva, K. Z.; Iordanskii, A. L.

2009-01-01

Complex investigation of the equilibrium sorption of water, diffusive transport of antiseptic, and morphology of mixed compositions based on polyoxybutirate and polyamide resin 54C has been performed to develop and analyze new biodegradable polymer compositions for controlled release of medicinal substances. Samples of mixtures were prepared by two methods: pressing under pressure and solvent evaporation from a polymer solution. The samples were compared and their morphology was analyzed by scanning electron microscopy. It is shown that the component ratio in the obtained mixtures affects their morphological, transport, and sorption characteristics.

Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations

Energy Technology Data Exchange (ETDEWEB)

Ma, Jincai [Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021 (China); USDA-ARS U. S. Salinity Laboratory, Riverside, CA 92507 (United States); Ibekwe, A. Mark, E-mail: Mark.Ibekwe@ars.usda.gov [USDA-ARS U. S. Salinity Laboratory, Riverside, CA 92507 (United States); Yang, Ching-Hong [Department of Biological Sciences, University of Wisconsin, Milwaukee, WI 53211 (United States); Crowley, David E. [Department of Environmental Sciences, University of California, Riverside, CA 92521 (United States)

2016-09-01

Microbial diversity of agricultural soils has been well documented, but information on leafy green producing soils is limited. In this study, we investigated microbial diversity and community structures in 32 (16 organic, 16 conventionally managed soils) from California (CA) and Arizona (AZ) using pyrosequencing, and identified factors affecting bacterial composition. Results of detrended correspondence analysis (DCA) and dissimilarity analysis showed that bacterial community structures of conventionally managed soils were similar to that of organically managed soils; while the bacterial community structures in soils from Salinas, California were different (P < 0.05) from those in soils from Yuma, Arizona and Imperial Valley, California. Canonical correspondence analysis (CCA) and artificial neural network (ANN) analysis of bacterial community structures and soil variables showed that electrical conductivity (EC), clay content, water-holding capacity (WHC), pH, total nitrogen (TN), and organic carbon (OC) significantly (P < 0.05) correlated with microbial communities. CCA based variation partitioning analysis (VPA) showed that soil physical properties (clay, EC, and WHC), soil chemical variables (pH, TN, and OC) and sampling location explained 16.3%, 12.5%, and 50.9%, respectively, of total variations in bacterial community structure, leaving 13% of the total variation unexplained. Our current study showed that bacterial community composition and diversity in major fresh produce growing soils from California and Arizona is a function of soil physiochemical characteristics and geographic distances of sampling sites. - Highlights: • Geographic distance was the most significant factor affecting microbial composition. • Physical and chemical properties significantly impacted microbial communities. • Higher numbers of OTUs were observed in organic soils than in convention soils.

Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations

International Nuclear Information System (INIS)

Ma, Jincai; Ibekwe, A. Mark; Yang, Ching-Hong; Crowley, David E.

2016-01-01

Microbial diversity of agricultural soils has been well documented, but information on leafy green producing soils is limited. In this study, we investigated microbial diversity and community structures in 32 (16 organic, 16 conventionally managed soils) from California (CA) and Arizona (AZ) using pyrosequencing, and identified factors affecting bacterial composition. Results of detrended correspondence analysis (DCA) and dissimilarity analysis showed that bacterial community structures of conventionally managed soils were similar to that of organically managed soils; while the bacterial community structures in soils from Salinas, California were different (P < 0.05) from those in soils from Yuma, Arizona and Imperial Valley, California. Canonical correspondence analysis (CCA) and artificial neural network (ANN) analysis of bacterial community structures and soil variables showed that electrical conductivity (EC), clay content, water-holding capacity (WHC), pH, total nitrogen (TN), and organic carbon (OC) significantly (P < 0.05) correlated with microbial communities. CCA based variation partitioning analysis (VPA) showed that soil physical properties (clay, EC, and WHC), soil chemical variables (pH, TN, and OC) and sampling location explained 16.3%, 12.5%, and 50.9%, respectively, of total variations in bacterial community structure, leaving 13% of the total variation unexplained. Our current study showed that bacterial community composition and diversity in major fresh produce growing soils from California and Arizona is a function of soil physiochemical characteristics and geographic distances of sampling sites. - Highlights: • Geographic distance was the most significant factor affecting microbial composition. • Physical and chemical properties significantly impacted microbial communities. • Higher numbers of OTUs were observed in organic soils than in convention soils

Recovery of iron/iron oxide nanoparticles from solution: comparison of methods and their effects

International Nuclear Information System (INIS)

Nurmi, James T.; Sarathy, Vaishnavi; Tratnyek, Paul G.; Baer, Donald R.; Amonette, James E.; Karkamkar, Abhi

2011-01-01

Most methods currently being used to recover Fe 0 -core/oxide-shell nanoparticles from solutions (including the solvents they are synthesized or stored in) are potentially problematic because they may alter the particle composition (e.g., depositing salts formed from solutes) or leave the particles prone to transformations during subsequent storage and handling (e.g., due to residual moisture). In this study, several methods for recovery of nanoparticles from aqueous solution were studied to determine how they affect the structure and reactivity of the recovered materials. Simple washing of the nanoparticles during vacuum filtration (i.e., “flash drying”) can leave up to ∼17 wt% residual moisture. Modeling calculations suggest this moisture is mostly capillary or matric water held between particles and particle aggregates, which can be removed by drying for short periods at relative vapor pressures below 0.9. Flash drying followed by vacuum drying, all under N 2 , leaves no detectable residue from precipitation of solutes (detectable by X-ray photoelectron spectroscopy, XPS), no significant changes in overall particle composition or structure (determined by transmission electron microscopy, TEM), and negligible residual moisture (by thermogravimetric analysis, TGA). While this improved flash-drying protocol may be the preferred method for recovering nanoparticles for many purposes, we found that Fe 0 -core/oxide-shell nanoparticles still exhibit gradual aging during storage when characterized electrochemically with voltammetry.

Retraction of 'Composition design and mechanical properties of BCC Ti solid solution alloys with low Young's modulus'

International Nuclear Information System (INIS)

Tulugan, Keli Mu; Park, Cheol Hong; Park, Won Jo; Qing, Wang

2012-01-01

The article 'Composition design and mechanical properties of BCC Ti solid solution alloys with low Young's modulus' has been retracted upon the request of the third author (Prof. Wang Qing, the first author's former advisor during his internship at DaLian University of Technology). The article was published without the third author's knowledge and consent. The corresponding author (Prof. Wonjo Park) apologizes to the third author, to the readers, and to the editorial staff of the JMST. The JMST editorial board does not tolerate such actions from authors and we will take appropriate action to prevent this from happening in the future

Kevlar reinforced neoprene composites

International Nuclear Information System (INIS)

Penn, B.G.; Daniels, J.G.; White, W.T.; Thompson, L.M.; Clemons, L.M.

1985-01-01

Kevlar/neoprene composites were prepared by two techniques. One method involved the fabrication of a composite from a rubber prepreg prepared by coating kevlar with viscous neoprene solution and then allowing the solvent to evaporate (solution impregnation technique). The second method involved heating a stack of kevlar/neoprene sheets at a temperature sufficient to cause polymer flow (melt flow technique). There was no significant difference in the breaking strength and percent elongation for samples obtained by the two methods; however the shear strength obtained for samples fabricated by the solution impregnation technique (275 psi) was significantly higher than that found for the melt flow fabricated samples (110 psi). 1 reference, 2 tables

Free vibration response of a multilayer smart hybrid composite plate with embedded SMA wires

Directory of Open Access Journals (Sweden)

K. Malekzadeh

Full Text Available In this paper, free vibration response of a hybrid composite plate was studied. Effects of some geometrical, physical and material parameters on response of the composite plates embedded with shape memory alloy (SMA wires were investigated, which have not been reported in the literature thus far. Some of these parameters included important factors affecting free vibration response of the smart hybrid composite plates. The SMA wires were embedded within the layers of the composite laminate. First-order shear deformation theory (FSDT was utilized to obtain the governing equations of hybrid composite plates. Transverse shear and rotary inertia effects of the plate were taken into consideration. For simply-supported boundary conditions, systematic closed form solutions were obtained by Navier's technique. It was established that dynamic behavior of the smart hybrid composite plate depended on various parameters such as volume fraction, temperature dependent recovery stress and tensile pre-strain of SMA wires and aspect ratio of the laminated hybrid plate.

Influence of gold species (AuCl4(-) and AuCl2(-)) on self-assembly of PS-b-P2VP in solutions and morphology of composite thin films fabricated at the air/liquid interfaces.

Science.gov (United States)

Zhao, Xingjuan; Wang, Qian; Zhang, Xiaokai; Lee, Yong-Ill; Liu, Hong-Guo

2016-01-21

Composite thin films doped with Au species were fabricated at an air/liquid interface via a series of steps, including the mass transfer of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) across the liquid/liquid interface between a DMF/CHCl3 solution and an aqueous solution containing either AuCl4(-) or AuCl2(-), self-assembly of PS-b-P2VP in a mixed DMF-water solution, and adsorption and further self-organization of the formed aggregates at the air/liquid interface. This is a new approach for fabricating composite polymer films and can be completed within a very short time. AuCl4(-) and AuCl2(-) ions were found to significantly influence the self-assembly behavior of the block copolymer and the morphologies of the composite films, leading to the formation of nanowire arrays and a foam structure at the air/liquid interface, respectively, which originated from rod-like micelles and microcapsules that had formed in the respective solutions. The effect of the metal complex was analyzed based on the packing parameters of the amphiphilic polymer molecules in different microenvironments and the interactions between the pyridine groups and the metal chloride anions. In addition, these composite thin films exhibited stable and durable performance as heterogeneous catalysts for the hydrogenation of nitroaromatics in aqueous solutions.

Chemical composition and electronic structure of the passive layer formed on stainless steels in a glucose-oxidase solution

Energy Technology Data Exchange (ETDEWEB)

Marconnet, C. [Laboratoire de Genie des Procedes et des Materiaux, Ecole Centrale Paris, Grande Voie des Vignes, 92290 CHATENAY-MALABRY (France)], E-mail: cyril.marconnet@yahoo.fr; Wouters, Y. [Science et Ingenierie des Materiaux et Procedes, Institut National Polytechnique de Grenoble, F-38402 Saint-Martin d' Heres Cedex (France); Miserque, F. [Laboratoire de Reactivite des Surfaces et des Interfaces, CEA Saclay, Bat. 391, 91191 GIF-SUR-YVETTE (France); Dagbert, C. [Laboratoire de Genie des Procedes et des Materiaux, Ecole Centrale Paris, Grande Voie des Vignes, 92290 CHATENAY-MALABRY (France)], E-mail: catherine.dagbert@ecp.fr; Petit, J.-P. [Laboratoire d' Electrochimie et de Physico-chimie des Materiaux et des Interfaces, INPG, F-38402 Saint-Martin d' Heres Cedex (France); Galerie, A. [Science et Ingenierie des Materiaux et Procedes, Institut National Polytechnique de Grenoble, F-38402 Saint-Martin d' Heres Cedex (France); Feron, D. [Service de Corrosion et du Comportement des Materiaux dans leur Environnement, CEA Saclay, Bat. 458, 91191 GIF-SUR-YVETTE (France)

2008-12-01

This article deals with the interaction between the passive layer formed on UNS S30403 and S31254 stainless steels and an enzymatic solution containing glucose oxidase (GOx) and its substrate D-glucose. This enzymatic solution is often used to reproduce in laboratory the ennoblement occuring in non-sterile aerated aqueous environments because of the biofilm settlement on the surface of the metallic material. GOx catalyses the oxidation of D-glucose to gluconic acid by reducing oxygen to hydrogen peroxide and produces an organic acid. Thanks to photocurrent measurements, XPS analysis and Mott-Schottky diagrams, it is here shown that such an environment generates modifications in the chemical composition and electronic structure of the passive layer: it induces a relative enrichment of the n-type semi-conducting phase containing chromium (chromine Cr{sub 2}O{sub 3}) and an increase of the donors density in the space charge region.

Chemical composition and electronic structure of the passive layer formed on stainless steels in a glucose-oxidase solution

International Nuclear Information System (INIS)

Marconnet, C.; Wouters, Y.; Miserque, F.; Dagbert, C.; Petit, J.-P.; Galerie, A.; Feron, D.

2008-01-01

This article deals with the interaction between the passive layer formed on UNS S30403 and S31254 stainless steels and an enzymatic solution containing glucose oxidase (GOx) and its substrate D-glucose. This enzymatic solution is often used to reproduce in laboratory the ennoblement occuring in non-sterile aerated aqueous environments because of the biofilm settlement on the surface of the metallic material. GOx catalyses the oxidation of D-glucose to gluconic acid by reducing oxygen to hydrogen peroxide and produces an organic acid. Thanks to photocurrent measurements, XPS analysis and Mott-Schottky diagrams, it is here shown that such an environment generates modifications in the chemical composition and electronic structure of the passive layer: it induces a relative enrichment of the n-type semi-conducting phase containing chromium (chromine Cr 2 O 3 ) and an increase of the donors density in the space charge region

Dietary boron does not affect tooth strength, micro-hardness, and density, but affects tooth mineral composition and alveolar bone mineral density in rabbits fed a high-energy diet.

Science.gov (United States)

Hakki, Sema S; SiddikMalkoc; Dundar, Niyazi; Kayis, Seyit Ali; Hakki, Erdogan E; Hamurcu, Mehmet; Baspinar, Nuri; Basoglu, Abdullah; Nielsen, Forrest H; Götz, Werner

2015-01-01

The objective of this study was to determine whether dietary boron (B) affects the strength, density and mineral composition of teeth and mineral density of alveolar bone in rabbits with apparent obesity induced by a high-energy diet. Sixty female, 8-month-old, New Zealand rabbits were randomly assigned for 7 months into five groups as follows: (1) control 1, fed alfalfa hay only (5.91 MJ/kg and 57.5 mg B/kg); (2) control 2, high energy diet (11.76 MJ and 3.88 mg B/kg); (3) B10, high energy diet + 10 mg B gavage/kg body weight/96 h; (4) B30, high energy diet + 30 mg B gavage/kg body weight/96 h; (5) B50, high energy diet + 50 mg B gavage/kg body weight/96 h. Maxillary incisor teeth of the rabbits were evaluated for compression strength, mineral composition, and micro-hardness. Enamel, dentin, cementum and pulp tissue were examined histologically. Mineral densities of the incisor teeth and surrounding alveolar bone were determined by using micro-CT. When compared to controls, the different boron treatments did not significantly affect compression strength, and micro-hardness of the teeth, although the B content of teeth increased in a dose-dependent manner. Compared to control 1, B50 teeth had decreased phosphorus (P) concentrations. Histological examination revealed that teeth structure (shape and thickness of the enamel, dentin, cementum and pulp) was similar in the B-treated and control rabbits. Micro CT evaluation revealed greater alveolar bone mineral density in B10 and B30 groups than in controls. Alveolar bone density of the B50 group was not different than the controls. Although the B treatments did not affect teeth structure, strength, mineral density and micro-hardness, increasing B intake altered the mineral composition of teeth, and, in moderate amounts, had beneficial effects on surrounding alveolar bone.

Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites.

Science.gov (United States)

Kierys, Agnieszka; Krasucka, Patrycja; Grochowicz, Marta

2017-11-01

The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS). The polymers selected for this study were poly(TRIM) and poly(HEMA- co -TRIM) produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM)-IBS and/or poly(HEMA- co -TRIM)-IBS) with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

Vapour-phase method in the synthesis of polymer-ibuprofen sodium-silica gel composites

Directory of Open Access Journals (Sweden)

Agnieszka Kierys

2017-11-01

Full Text Available The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS. The polymers selected for this study were poly(TRIM and poly(HEMA-co-TRIM produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM-IBS and/or poly(HEMA-co-TRIM-IBS with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

Use of azeotropic distillation for isotopic analysis of deuterium in soil water and saturate saline solution

International Nuclear Information System (INIS)

Santos, Antonio Vieira dos.

1995-05-01

The azeotropic distillation technique was adapted to extract soil water and saturate saline solution, which is similar to the sea water for the Isotopic Determination of Deuterium (D). A soil test was used to determine the precision and the nature of the methodology to extract soil water for stable isotopic analysis, using the azeotropic distillation and comparing with traditional methodology of heating under vacuum. This methodology has been very useful for several kinds of soil or saturate saline solution. The apparatus does not have a memory effect, and the chemical reagents do not affect the isotopic composition of soil water. (author). 43 refs., 10 figs., 12 tabs

Effect of chemical treatment of Kevlar fibers on mechanical interfacial properties of composites.

Science.gov (United States)

Park, Soo-Jin; Seo, Min-Kang; Ma, Tae-Jun; Lee, Douk-Rae

2002-08-01

In this work, the effects of chemical treatment on Kevlar 29 fibers have been studied in a composite system. The surface characteristics of Kevlar 29 fibers were characterized by pH, acid-base value, X-ray photoelectron spectroscopy (XPS), and FT-IR. The mechanical interfacial properties of the final composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and specific fracture energy (G(IC)). Also, impact properties of the composites were investigated in the context of differentiating between initiation and propagation energies and ductile index (DI) along with maximum force and total energy. As a result, it was found that chemical treatment with phosphoric acid solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improved mechanical interfacial strength in the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force between fibers and matrix in a composite system.

High temperature resistant cermet and ceramic compositions

Science.gov (United States)

Phillips, W. M. (Inventor)

1978-01-01

Cermet compositions having high temperature oxidation resistance, high hardness and high abrasion and wear resistance, and particularly adapted for production of high temperature resistant cermet insulator bodies are presented. The compositions are comprised of a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Also disclosed are novel ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride.

Characterisation of solution cast cellulose nanofibre – reinforced poly(lactic acid

Directory of Open Access Journals (Sweden)

2010-01-01

Full Text Available Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Composite films containing 2.5 and 5.0 wt% flax cellulose (FC fibres were prepared by solution casting of mixtures of poly(lactic acid (PLA solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solution cast pure PLA film, with thickness of around 160 m, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.

Wind sorting affects differently the organo-mineral composition of saltating and particulate materials in contrasting texture agricultural soils

Science.gov (United States)

Iturri, Laura Antonela; Funk, Roger; Leue, Martin; Sommer, Michael; Buschiazzo, Daniel Eduardo

2017-10-01

There is little information about the mineral and organic composition of sediments eroded by wind at different heights. Because of that, wind tunnel simulations were performed on four agricultural loess soils of different granulometry and their saltating materials collected at different heights. The particulate matter with an aerodynamic diameter mainly smaller than 10 μm (PM10) of these soils was obtained separately by a laboratory method. Results indicated that the granulometric composition of sediments collected at different heights was more homogeneous in fine- than in sandy-textured soils, which were more affected by sorting effects during wind erosion. This agrees with the preferential transport of quartz at low heights and of clay minerals at greater heights. SOC contents increased with height, but the composition of the organic materials was different: stable carboxylic acids, aldehydes, amides and aromatics were preferentially transported close to the ground because their were found in larger aggregates, while plant debris and polysaccharides, carbohydrates and derivatives of microbial origin from organic matter dominated at greater heights for all soil types. The amount of SOC in the PM10 fraction was higher when it was emitted from sandy than from fine textured soils. Because of the sorting process produced by wind erosion, the stable organic matter compounds will be transported at low heights and local scales, modifying soil fertility due to nutrient exportation, while less stable organic compounds will be part of the suspension losses, which are known to affect some processes at regional- or global scale.

Facile synthesis of silver immobilized-poly(methyl methacrylate)/polyethyleneimine core-shell particle composites

Energy Technology Data Exchange (ETDEWEB)

Jenjob, Somkieath [Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand); Center of Excellence for Innovation in Chemistry (PERCH-CIC), Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Ratchathewi, Bangkok 10400 (Thailand); Tharawut, Teeralak [Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand); Sunintaboon, Panya, E-mail: panya.sun@mahidol.ac.th [Department of Chemistry, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand); Center of Excellence for Innovation in Chemistry (PERCH-CIC), Department of Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Ratchathewi, Bangkok 10400 (Thailand); Center for Alternative Energy, Faculty of Science, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Nakhon Pathom 73170 (Thailand)

2012-10-01

A facile route to synthesize silver-embedded-poly(methyl methacrylate)/polyethyleneimine (PMMA/PEI-Ag) core-shell particle composites was illustrated in this present work. PMMA/PEI core-shell particle templates were first prepared by a surfactant-free emulsion polymerization. PEI on the templates' surface was further used to complex and reduce Ag{sup +} ions (from silver nitrate solution) to silver nanoparticles (AgNPs) at ambient temperature, resulting in the PMMA/PEI-Ag particle composites. The formation of AgNPs was affected by the pHs of the reaction medium. The pH of reaction medium at 6.5 was optimal for the formation of PMMA/PEI-Ag with good colloidal stability, which was confirmed by size and size distribution, FTIR spectroscopy, UV-vis spectroscopy and X-ray diffraction. Moreover, the amount of AgNO{sub 3} solution (4.17-12.50 g) was found to affect the formation of AgNPs. Transmission electron microscopy (TEM) indicated that the AgNPs were incorporated in the PMMA/PEI core-shell matrix, and had 6-10 nm in diameter. AgNPs immobilized on PMMA/PEI core-shell particles were also investigated by energy dispersive X-ray spectroscopy analysis mode extended from scanning electron microscopy (SEM/EDS). Furthermore, the presence of AgNPs was found to influence the thermal degradation behavior of PMMA/PEI particle composites as observed through thermogravimetric analysis (TGA). Highlights: Black-Right-Pointing-Pointer A 2-step synthesis of Ag immobilized-PMMA/PEI particle composites was shown. Black-Right-Pointing-Pointer PMMA/PEI core-shell templates were first formed and PEI assisted AgNP formation. Black-Right-Pointing-Pointer Formation of PMMA/PEI-Ag was affected by pH of medium and amount of AgNO{sub 3}. Black-Right-Pointing-Pointer PMMA/PEI-Ag can be confirmed by color change, UV-vis, TEM, SEM with EDS, and X-ray. Black-Right-Pointing-Pointer Effect of AgNPs on thermal degradation of PMMA/PEI-Ag can be observed through TGA.

Lipid Bilayer Composition Affects Transmembrane Protein Orientation and Function

Directory of Open Access Journals (Sweden)

Katie D. Hickey

2011-01-01

Full Text Available Sperm membranes change in structure and composition upon ejaculation to undergo capacitation, a molecular transformation which enables spermatozoa to undergo the acrosome reaction and be capable of fertilization. Changes to the membrane environment including lipid composition, specifically lipid microdomains, may be responsible for enabling capacitation. To study the effect of lipid environment on proteins, liposomes were created using lipids extracted from bull sperm membranes, with or without a protein (Na+ K+-ATPase or -amylase. Protein incorporation, function, and orientation were determined. Fluorescence resonance energy transfer (FRET confirmed protein inclusion in the lipid bilayer, and protein function was confirmed using a colourometric assay of phosphate production from ATP cleavage. In the native lipid liposomes, ATPase was oriented with the subunit facing the outer leaflet, while changing the lipid composition to 50% native lipids and 50% exogenous lipids significantly altered this orientation of Na+ K+-ATPase within the membranes.

Structure of the heat-affected zone in the 24 Kh2NMFA steel welded joints

International Nuclear Information System (INIS)

German, S.I.; Levenberg, N.E.; Netesa, E.M.; Fomina, O.P.

1977-01-01

It is shown that in the heat-affected zone of the joints welded with preheating there appears a bainite having a complex composition and the following structure: asub(m)+(M+Asub(ret)). The matrix of the bainite is represented by an a-solid solution formed by martensite kinetics (asub(m)). Small regions of granular or elongated shape, uniformly distributed over the bainite matrix, are either a retained austenite (Asub(ret)) or a martensite with a retained austenite (M+Asub(ret)). The non-equilibrium character of the bainite phases is, to a large extent, responsible for the inadmissably high hardness of the heat-affected zone immediately after welding

Measurement and modeling of diameter distributions of particulate matter in terrestrial solutions

Science.gov (United States)

Levia, Delphis F.; Michalzik, Beate; Bischoff, Sebastian; NäThe, Kerstin; Legates, David R.; Gruselle, Marie-Cecile; Richter, Susanne

2013-04-01

Particulate matter (PM) plays an important role in biogeosciences, affecting biosphere-atmosphere interactions and ecosystem health. This is the first known study to quantify and model PM diameter distributions of bulk precipitation, throughfall, stemflow, and organic layer (Oa) solution. Solutions were collected from a European beech (Fagus sylvatica L.) forest during leafed and leafless periods. Following scanning electron microscopy and image analysis, PM distributions were quantified and then modeled with the Box-Cox transformation. Based on an analysis of 43,278 individual particulates, median PM diameter of all solutions was around 3.0 µm. All PM diameter frequency distributions were skewed significantly to the right. Optimal power transformations of PM diameter distributions were between -1.00 and -1.56. The utility of this model reconstruction would be that large samples having a similar probability density function can be developed for similar forests. Further work on the shape and chemical composition of particulates is warranted.

Effects of sorption and temperature on solute transport in unsaturated steady flow

International Nuclear Information System (INIS)

Fuentes, H.R.; Polzer, W.L.; Essington, E.H.

1986-01-01

It is known that temperature affects physical and chemical processes and that these processes may alter the transport of solutes in the environment. Laboratory column studies were performed in unsaturated flow conditions with a composite pulse containing iodide, cobalt, cesium and strontium each at 10 -3 M. The experiments were performed with Bandelier Tuff and produced breakthrough curves that indicate significant changes in transport due to a temperature change from 25 0 C to 5 0 C for nonconservative solutes. Also, the interpretation of the temperature and sorption data suggest that the differences in transport between 5 0 C and 25 0 C for nonconservative solutes may be predicted in a qualitative manner from batch equilibrium and nonequilibrium sorption data and the theory of sorption used in deriving the modified Freundlich isotherm equation. These effects should be of concern in modeling and management of spills and waste disposal within this range of environmental temperatures

Lead Sorption from Aqueous Solutions by Pseudomonas putida (p168 and its Composites with Palygorskite and Sepiolite Clays

Directory of Open Access Journals (Sweden)

Marzieh tavanaei

2017-02-01

Full Text Available Introduction: Heavy metals contamination due to natural and anthropogenic sources is a global environmental concern. Lead (Pb is one of the very toxic heavy metals. Industrial production processes and their emissions, mining operation, smelting, combustion sources and solid waste incinerators are the primary sources of lead. This heavy metal has aberrant effects on the environment and living organisms. Hence, proper treatment of lead from soil and industrial wastewaters is very important. In order to remove toxic heavy metals from contaminated water systems, conventional methods such as chemical precipitation, coagulation, ion exchange, solvent extraction and filtration, evaporation and membrane methods are being used. These conventional methods generally have high costs and technical problems. Therefore, biosorption processes, in which microorganisms are used as sorbents, have been considered as economical and environmentally friendly options for removal of heavy metals from aqueous solution. Clay minerals are another group of sorbents used in removal of heavy metals from polluted environments. Furthermore, bacterial cells can be attached on clay mineral surfaces and form bacteria-mineral composites. These composites adsorb heavy metals and convert them into forms with low mobility and bioavailability. Pseudomonas putida is a unique microorganism with a high tendency to sorb and/or degrade certain environmental pollutants. Palygorskite and sepiolite are the fibrous clay minerals of arid and semiarid regions; their structures consist of ribbons and channels. These fibrous minerals have various applications in industry and the environment because of its large surface area and high adsorption capacity. The present study was conducted in order to determine the ability of Pseudomonas putida (P168, and its composites with palygorskite and sepiolite in lead sorption. Materials and Methods: The bacterial strain used in the present study was Pseudomonas

Gamma radiation and osmotic potential of the nutrient solution differentially affect macronutrient concentrations, pH and EC in chilhuacle pepper fruits

International Nuclear Information System (INIS)

Victor Garcia-Gaytan, Libia Iris Trejo-Tellez; Olga Tejeda-Sartorius; Maribel Ramirez-Martinez; Julian Delgadillo-Martinez; Fernando Carlos Gomez-Merino; Soledad Garcia-Morales

2018-01-01

Chilhuacle pepper (Capsicum annuum L.) seeds were exposed to gamma radiation (GR) doses (0, 10, 80 and 120 Gy), and plants were grown in hydroponics with different osmotic potentials (OP) (- 0.036, - 0.072, - 0.092, and - 0.108 MPa) in the nutrient solution. We measured the nutrient concentrations, pH and electrical conductivity (EC) in fruits at different time points after transplanting (70, 90 and 130 dat), and found the GR, nutrient solution OP and their interactions differentially affected N, P, K, Ca, and Mg concentrations, as well as pH and EC in chilhuacle peppers. (author)

Alterations in welding process voltage affect the generation of ultrafine particles, fume composition, and pulmonary toxicity.

Science.gov (United States)

Antonini, James M; Keane, Michael; Chen, Bean T; Stone, Samuel; Roberts, Jenny R; Schwegler-Berry, Diane; Andrews, Ronnee N; Frazer, David G; Sriram, Krishnan

2011-12-01

The goal was to determine if increasing welding voltage changes the physico-chemical properties of the fume and influences lung responses. Rats inhaled 40 mg/m³ (3 h/day × 3 days) of stainless steel (SS) welding fume generated at a standard voltage setting of 25 V (regular SS) or at a higher voltage (high voltage SS) of 30 V. Particle morphology, size and composition were characterized. Bronchoalveolar lavage was performed at different times after exposures to assess lung injury. Fumes collected from either of the welding conditions appeared as chain-like agglomerates of nanometer-sized primary particles. High voltage SS welding produced a greater number of ultrafine-sized particles. Fume generated by high voltage SS welding was higher in manganese. Pulmonary toxicity was more substantial and persisted longer after exposure to the regular SS fume. In summary, a modest raise in welding voltage affected fume size and elemental composition and altered the temporal lung toxicity profile.

Factors affecting the species composition of arable field boundary vegetation

NARCIS (Netherlands)

Kleijn, D.; Verbeek, M.

2000-01-01

1. In recent decades the botanical diversity of arable field boundaries has declined drastically. To determine the most important factors related to the species composition of arable field boundaries, the vegetation composition of 105 herbaceous boundaries, 1-m wide, in the central and eastern

Does the light source affect the repairability of composite resins?

Science.gov (United States)

Karaman, Emel; Gönülol, Nihan

2014-01-01

The aim of this study was to examine the effect of the light source on the microshear bond strength of different composite resins repaired with the same substrate. Thirty cylindrical specimens of each composite resin--Filtek Silorane, Filtek Z550 (3M ESPE), Gradia Direct Anterior (GC), and Aelite Posterior (BISCO)--were prepared and light-cured with a QTH light curing unit (LCU). The specimens were aged by thermal cycling and divided into three subgroups according to the light source used--QTH, LED, or PAC (n = 10). They were repaired with the same substrate and a Clearfil Repair Kit (Kuraray). The specimens were light-cured and aged for 1 week in distilled water at 37 °C. The microshear bond strength and failure modes were assessed. There was no significant difference in the microshear bond strength values among the composite resins, except for the Filtek Silorane group that showed significantly lower bond strength values when polymerized with the PAC unit compared to the QTH or LED unit. In conclusion, previously placed dimethacrylate-based composites can be repaired with different light sources; however, if the composite to be repaired is silorane-based, then using a QTH or LED device may be the best option.

Radiolabelled sucralfate compositions

International Nuclear Information System (INIS)

Vasquez, T.E.; Bridges, R.L.; Braunstein, P.; Jansholt, A.

1984-01-01

A novel radiopharmaceutical composition comprising an aqueous solution or suspension containing a radiolabelled sucralfate or sucralfate derivative or precursor is claimed. The composition is effective for in vivo scintigraphic imaging of the gastrointestinal muscosal areas in humans. The sucralfate is combined with a radiolabelled albumin or other protein or protein derivative under acidic conditions

Stress-tuned conductor-polymer composite for use in sensors

Science.gov (United States)

Martin, James E; Read, Douglas H

2013-10-22

A method for making a composite polymeric material with electrical conductivity determined by stress-tuning of the conductor-polymer composite, and sensors made with the stress-tuned conductor-polymer composite made by this method. Stress tuning is achieved by mixing a miscible liquid into the polymer precursor solution or by absorbing into the precursor solution a soluble compound from vapor in contact with the polymer precursor solution. The conductor may or may not be ordered by application of a magnetic field. The composite is formed by polymerization with the stress-tuning agent in the polymer matrix. The stress-tuning agent is removed following polymerization to produce a conductor-polymer composite with a stress field that depends on the amount of stress-tuning agent employed.

Equilibrium Adsorption of heavy Metals from Aqueous Solutions onto Poly aniline Stannic(IV) Phosphate Composite

International Nuclear Information System (INIS)

El-Zahhar, A.A.; EI-Shourbagy, M.M.; Shady, S.A.

2012-01-01

An adsorbent material has been prepared by immobilization of stannic(IV) phosphate within poly aniline composite. The produced adsorbent exhibit a high adsorption potential for Pb(II), Cd(Il) and Zn(lI) from aqueous solutions. The influence of initial metal ion concentration, adsorbent dose, ph and temperature on metal ion removal has been studied. The process was found to follow a first order rate kinetics. Thc intra-particle diffusion of metal ions through pores in the adsorbent was to be the main rate limiting step. The equilibrium data fit well with Langmuir adsorption isotherm model. The selectivity order of the adsorbent towards the metal ions was Pb(Il) > Cd(Il) >Zn(II). The adsorption rate constant and thermodynamic parameters were also given to predict the nature of adsorption

Improved mechanical and corrosion properties of nickel composite coatings by incorporation of layered silicates

Energy Technology Data Exchange (ETDEWEB)

Tientong, J. [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States); Ahmad, Y.H. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Nar, M.; D' Souza, N. [University of North Texas, Department of Mechanical and Energy Engineering, Denton, TX 76207 (United States); Mohamed, A.M.A. [Center for Advanced Materials, P.O. Box 2713, Qatar University, Doha (Qatar); Golden, T.D., E-mail: tgolden@unt.edu [University of North Texas, Department of Chemistry, 1155 Union Circle #305070, Denton, TX 76203 (United States)

2014-05-01

Layered silicates as exfoliated montmorillonite are incorporated into nickel films by electrodeposition, enhancing both corrosion resistance and hardness. Films were deposited onto stainless steel from a plating solution adjusted to pH 9 containing nickel sulfate, sodium citrate, and various concentrations of exfoliated montmorillonite. The presence of the incorporated layered silicate was confirmed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The composite films were also compact and smooth like the pure nickel films deposited under the same conditions as shown by scanning electron microscopy. X-ray diffraction results showed that incorporation of layered silicates into the film do not affect the nickel crystalline fcc structure. The nanocomposite films exhibited improved stability and adhesion. Pure nickel films cracked and peeled from the substrate when immersed in 3.5% NaCl solution within 5 days, while the nanocomposite films remained attached even after 25 days. The corrosion resistance of the nickel nanocomposites was also improved compared to nickel films. Nickel-layered silicate composites showed a 25% increase in Young's modulus and a 20% increase in hardness over pure nickel films. - Highlights: • 0.05–2% of layered silicates are incorporated into crystalline nickel films. • Resulting composite films had improved stability and adhesion. • Corrosion resistance improved for the composite films. • Hardness improved 20% and young's modulus improved 25% for the composite films.

Explicit solutions of the Camassa-Holm equation

International Nuclear Information System (INIS)

Parkes, E.J.; Vakhnenko, V.O.

2005-01-01

Explicit travelling-wave solutions of the Camassa-Holm equation are sought. The solutions are characterized by two parameters. For propagation in the positive x-direction, both periodic and solitary smooth-hump, peakon, cuspon and inverted-cuspon waves are found. For propagation in the negative x-direction, there are solutions which are just the mirror image in the x-axis of the aforementioned solutions. Some composite wave solutions of the Degasperis-Procesi equation are given in an appendix

Brucella abortus choloylglycine hydrolase affects cell envelope composition and host cell internalization.

Directory of Open Access Journals (Sweden)

María Inés Marchesini

Full Text Available Choloylglycine hydrolase (CGH, E.C. 3.5.1.24 is a conjugated bile salt hydrolase that catalyses the hydrolysis of the amide bond in conjugated bile acids. Bile salt hydrolases are expressed by gastrointestinal bacteria, and they presumably decrease the toxicity of host's conjugated bile salts. Brucella species are the causative agents of brucellosis, a disease affecting livestock and humans. CGH confers Brucella the ability to deconjugate and resist the antimicrobial action of bile salts, contributing to the establishment of a successful infection through the oral route in mice. Additionally, cgh-deletion mutant was also attenuated in intraperitoneally inoculated mice, which suggests that CGH may play a role during systemic infection other than hydrolyzing conjugated bile acids. To understand the role CGH plays in B. abortus virulence, we infected phagocytic and epithelial cells with a cgh-deletion mutant (Δcgh and found that it is defective in the internalization process. This defect along with the increased resistance of Δcgh to the antimicrobial action of polymyxin B, prompted an analysis of the cell envelope of this mutant. Two-dimensional electrophoretic profiles of Δcgh cell envelope-associated proteins showed an altered expression of Omp2b and different members of the Omp25/31 family. These results were confirmed by Western blot analysis with monoclonal antibodies. Altogether, the results indicate that Brucella CGH not only participates in deconjugation of bile salts but also affects overall membrane composition and host cell internalization.

Factors affecting the bacterial community composition and heterotrophic production of Columbia River estuarine turbidity maxima.

Science.gov (United States)

Herfort, Lydie; Crump, Byron C; Fortunato, Caroline S; McCue, Lee Ann; Campbell, Victoria; Simon, Holly M; Baptista, António M; Zuber, Peter

2017-12-01

Estuarine turbidity maxima (ETM) function as hotspots of microbial activity and diversity in estuaries, yet, little is known about the temporal and spatial variability in ETM bacterial community composition. To determine which environmental factors affect ETM bacterial populations in the Columbia River estuary, we analyzed ETM bacterial community composition (Sanger sequencing and amplicon pyrosequencing of 16S rRNA gene) and bulk heterotrophic production ( 3 H-leucine incorporation rates). We collected water 20 times to cover five ETM events and obtained 42 samples characterized by different salinities, turbidities, seasons, coastal regimes (upwelling vs. downwelling), locations, and particle size. Spring and summer populations were distinct. All May samples had similar bacterial community composition despite having different salinities (1-24 PSU), but summer non-ETM bacteria separated into marine, freshwater, and brackish assemblages. Summer ETM bacterial communities varied depending on coastal upwelling or downwelling conditions and on the sampling site location with respect to tidal intrusion during the previous neap tide. In contrast to ETM, whole (>0.2 μm) and free-living (0.2-3 μm) assemblages of non-ETM waters were similar to each other, indicating that particle-attached (>3 μm) non-ETM bacteria do not develop a distinct community. Brackish water type (ETM or non-ETM) is thus a major factor affecting particle-attached bacterial communities. Heterotrophic production was higher in particle-attached than free-living fractions in all brackish waters collected throughout the water column during the rise to decline of turbidity through an ETM event (i.e., ETM-impacted waters). However, free-living communities showed higher productivity prior to or after an ETM event (i.e., non-ETM-impacted waters). This study has thus found that Columbia River ETM bacterial communities vary based on seasons, salinity, sampling location, and particle size, with the

A New Class of Ternary Compound for Lithium-Ion Battery: from Composite to Solid Solution.

Science.gov (United States)

Wang, Jiali; Wu, Hailong; Cui, Yanhua; Liu, Shengzhou; Tian, Xiaoqing; Cui, Yixiu; Liu, Xiaojiang; Yang, Yin

2018-02-14

Searching for high-performance cathode materials is a crucial task to develop advanced lithium-ion batteries (LIBs) with high-energy densities for electrical vehicles (EVs). As a promising lithium-rich material, Li 2 MnO 3 delivers high capacity over 200 mAh g -1 but suffers from poor structural stability and electronic conductivity. Replacing Mn 4+ ions by relatively larger Sn 4+ ions is regarded as a possible strategy to improve structural stability and thus cycling performance of Li 2 MnO 3 material. However, large difference in ionic radii of Mn 4+ and Sn 4+ ions leads to phase separation of Li 2 MnO 3 and Li 2 SnO 3 during high-temperature synthesis. To prepare solid-solution phase of Li 2 MnO 3 -Li 2 SnO 3 , a buffer agent of Ru 4+ , whose ionic radius is in between that of Mn 4+ and Sn 4+ ions, is introduced to assist the formation of a single solid-solution phase. The results show that the Li 2 RuO 3 -Li 2 MnO 3 -Li 2 SnO 3 ternary system evolves from mixed composite phases into a single solid-solution phase with increasing Ru content. Meanwhile, discharge capacity of this ternary system shows significantly increase at the transformation point which is ascribed to the improvement of Li + /e - transportation kinetics and anionic redox chemistry for solid-solution phase. The role of Mn/Sn molar ratio of Li 2 RuO 3 -Li 2 MnO 3 -Li 2 SnO 3 ternary system has also been studied. It is revealed that higher Sn content benefits cycling stability of the system because Sn 4+ ions with larger sizes could partially block the migration of Mn 4+ and Ru 4+ from transition metal layer to Li layer, thus suppressing structural transformation of the system from layered-to-spinel phase. These findings may enable a new route for exploring ternary or even quaternary lithium-rich cathode materials for LIBs.

Selective adsorption of cationic dyes from aqueous solution by polyoxometalate-based metal–organic framework composite

Energy Technology Data Exchange (ETDEWEB)

Liu, Xiaoxia; Gong, Wenpeng; Luo, Jing; Zou, Chentao; Yang, Yun; Yang, Shuijin, E-mail: yangshuijin@163.com

2016-01-30

Graphical abstract: Selective adsorption ability of H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 toward MO (a), Rhb (b) and the removal rate of Rhb, MO and MB (c). - Highlights: • Using metal–organic framework (MOF) composite as an adsorbent was investigated. • Selective adsorption ability of the composite towards cationic dyes was proposed. • The removal rate of MOF was raised greatly by the modification of polyoxometalate. • The adsorption kinetic and isotherm were used to describe the adsorption process. • The thermodynamic parameters of the composite were investigated in detail. - Abstract: A novel environmental friendly adsorbent H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 was synthesized by a simple one-step reaction under solvothermal conditions and characterized by XRD, FTIR, thermogravimetric analyses (TGA) and N{sub 2} adsorption–desorption isotherms. The removal rate of H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 was quite greater (85%) than that of MOF-5 (almost zero), showing that the adsorption performance of porous MOF-5 can be improved through the modification of H{sub 6}P{sub 2}W{sub 18}O{sub 62}. Further study revealed that H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 exhibited a fast adsorption rate and selective adsorption ability towards the cationic dyes in aqueous solution. The removal rate was up to 97% for cationic dyes methylene blue (MB) and 68% for rhodamine B(Rhb) within 10 min. However, anionicdye methyl orange(MO) can only reach to 10%. The influences including initial concentration, contact time, initial solution pH and temperature of MB adsorption onto H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 were investigated in detail. The kinetic study indicated that the adsorption of MB onto H{sub 6}P{sub 2}W{sub 18}O{sub 62}/MOF-5 followed the pseudo second-order model well. The isotherm obtained from experimental data fitted the Langmuir model, yielding maximum adsorption capacity of 51.81 mg/g. The thermodynamic parameters analysis

Dry matter and nitrogen accumulation are not affected by superoptimal concentration of ammonium in flowing solution culture with pH control

Science.gov (United States)

Rideout, J. W.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

1994-01-01

While it is known that superoptimal concentrations of the nitrate (NO3-) ion in solution culture do not increase NO3- uptake or dry matter accumulation, the same is not known for the ammonium (NH4+) ion. An experiment was conducted utilizing flowing solution culture with pH control to investigate the influence of superoptimal NH4+ concentrations on dry matter, nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) accumulation by nonnodulated soybean plants. Increasing the NH4+ concentration in solution from 1 to 10 mM did not affect dry matter or N accumulation. Accumulations of K, Ca, and Mg were slightly decreased with increased NH4+ concentration. The NH4+ uptake system, which is saturated at less than 1mM NH4+, is able to regulate uptake of NH4+ at concentrations as high as 10 mM.

Quantitative relationship between adsorbed amount of solute and solvent composition

International Nuclear Information System (INIS)

Wang Yan; Geng Xindu; Zebolsky, Don M.

2003-01-01

A new adsorption isotherm that relates the amount of solute adsorbed to the solvent concentration is proposed. The new equation is derived from Geng and Shi's stoichiometric displacement model for adsorption (SDM-A). The obtained equation may be simplified to an expression containing two parameters. The equation with two parameters, valid for low concentrations of solute, is a logarithmically linear relationship. The intercept contains a thermodynamic equilibrium constant of the solute displacing solvent from the adsorbent. The slope is the negative value of the stoichiometric displacement parameter (Z), the average total number of solvent molecules displaced from an active site on the adsorbent and from the solute. Tests with a homologous series of aromatic alcohols by frontal analysis in reversed phase liquid chromatography demonstrate that experimental results fit the equation well

Performance and mechanisms for the removal of phthalates and pharmaceuticals from aqueous solution by graphene-containing ceramic composite tubular membrane coupled with the simultaneous electrocoagulation and electrofiltration process.

Science.gov (United States)

Yang, Gordon C C; Chen, Ying-Chun; Yang, Hao-Xuan; Yen, Chia-Heng

2016-07-01

In this study, commonly detected emerging contaminants (ECs) in water, including di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), cephalexin (CLX), sulfamethoxazole (SMX) and caffeine (CAF), were selected as the target contaminants. A lab-prepared graphene-containing ceramic composite tubular membrane (TGCCM) coupled with the simultaneous electrocoagulation and electrofiltration process (EC/EF) in crossflow filtration mode was used to remove target contaminants in model solution. Meanwhile, a comparison of the removal efficiency was made among various tubular composite membranes reported, including carbon fibers/carbon/alumina composite tubular membrane (TCCACM), titania/alumina composite tubular membrane (TTACM) and alumina tubular membrane (TAM). The results of this study showed that the removal efficiencies for DnBP and DEHP were 99%, whereas 32-97% for cephalexin (CLX), sulfamethoxazole (SMX) and caffeine (CAF). In this work the mechanisms involved in removing target ECs were proposed and their roles in removing various ECs were also discussed. Further, two actual municipal wastewaters were treated to evaluate the applicability of the aforementioned treatment technology (i.e., TGCCM coupled with EC/EF) to various aqueous solutions in the real world. Copyright © 2016 Elsevier Ltd. All rights reserved.

Kenaf Fibre Reinforced Polypropylene Composites: Effect of Cyclic Immersion on Tensile Properties

Directory of Open Access Journals (Sweden)

W. H. Haniffah

2015-01-01

Full Text Available This research studied the degradation of tensile properties of kenaf fibre reinforced polypropylene composites due to cyclic immersion into two different solutions, as well as comparison of the developed composites’ tensile properties under continuous and cyclic immersion. Composites with 40% and 60% fibre loadings were immersed in tap water and bleach for 4 cycles. Each cycle consisted of 3 days of immersion and 4 days of conditioning in room temperature (28°C and 55% humidity. The tensile strength and modulus of composites were affected by fibre composition, type of liquid of immersion, and number of cycles. The number of immersion cycles and conditioning caused degradation to tensile strength and modulus of kenaf fibre reinforced polypropylene composites. Continuous and cyclic immersion in bleach caused tensile strength of the composites to differ significantly whereas, for tensile modulus, the difference was insignificant in any immersion and fibre loadings. However, continuous immersion in the bleach reduced the tensile strength of composites more compared to cyclic immersion. These preliminary results suggest further evaluation of the suitability of kenaf fibre reinforced polypropylene composites for potential bathroom application where the composites will be exposed to water/liquid in cyclic manner due to discontinuous usage of bathroom.

Solute diffusivity in undisturbed soil

DEFF Research Database (Denmark)

Lægdsmand, Mette; Møldrup, Per; Schjønning, Per

2012-01-01

Solute diffusivity in soil plays a major role in many important processes with relation to plant growth and environmental issues. Soil solute diffusivity is affected by the volumetric water content as well as the morphological characteristics of water-filled pores. The solute diffusivity in intact...

Raman scattering quantitative analysis of the anion chemical composition in kesterite Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} solid solutions

Energy Technology Data Exchange (ETDEWEB)

Dimitrievska, Mirjana, E-mail: mdimitrievska@irec.cat [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1 2pl., 08930 Sant Adrià del Besòs, Barcelona (Spain); Gurieva, Galina [Helmholtz Centre Berlin for Materials and Energy, Department Crystallography, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Xie, Haibing; Carrete, Alex [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1 2pl., 08930 Sant Adrià del Besòs, Barcelona (Spain); Cabot, Andreu [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1 2pl., 08930 Sant Adrià del Besòs, Barcelona (Spain); Institució Catalana de Recerca i Estudis Avançats – ICREA, Passeig Lluís Companys 23, 08010 Barcelona (Spain); Saucedo, Edgardo [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1 2pl., 08930 Sant Adrià del Besòs, Barcelona (Spain); Pérez-Rodríguez, Alejandro [Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1 2pl., 08930 Sant Adrià del Besòs, Barcelona (Spain); IN" 2UB, Departament d’Electrònica, Universitat de Barcelona, C. Martí i Franquès 1, 08028 Barcelona (Spain); and others

2015-04-15

Highlights: • An optical method for the quantitative measurement of [S]/([S] + [Se]) in CZTSSe is presented. • It is based on Raman spectroscopy and covers whole S–Se range of compositions. • The proposed method is independent of crystal quality, experimental conditions and type of material. • The validity of the technique is proven by comparison with independent composition measurements (XRD and EQE). • Test of the method on the data published in the literature has given satisfactory results. - Abstract: A simple and non destructive optical methodology for the quantitative measurement of [S]/([S] + [Se]) anion composition in kesterite Cu{sub 2}ZnSn(S{sub x}Se{sub 1−x}){sub 4} (CZTSSe) solid solutions by means of Raman spectroscopy in the whole S–Se range of compositions has been developed. This methodology is based on the dependence of the integral intensity ratio of Raman bands sensitive to anion vibrations with the [S]/([S] + [Se]) composition of the kesterite solid solutions. The calibration of the parameters used in this analysis involved the synthesis of a set of CZTSSe powders by solid state reaction method, spanning the range from pure Cu{sub 2}ZnSnS{sub 4} to pure Cu{sub 2}ZnSnSe{sub 4}. The validity of the methodology has been tested on different sets of independent samples, including also non-stoichiometric device grade CZTSSe layers with different compositions and films that were synthesized by solution based processes with different crystalline quality. In all cases, the comparison of the results obtained from the analysis of the intensity of the Raman bands with independent composition measurements performed by different techniques as X-ray diffraction and external quantum efficiency has confirmed the satisfactory performance of the developed methodology for the quantitative analysis of these compounds, independently on the crystal quality or the method of synthesis. Further strong support on the methodology performance has been

Permeability After Impact Testing of Composite Laminates

Science.gov (United States)

Nettles, Alan T.

2003-01-01

Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a non-linear fashion for almost all of the specimens tested.

Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

Directory of Open Access Journals (Sweden)

Richard C. Petersen

2014-12-01

Full Text Available The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo

Initial polishing time affects gloss retention in resin composites.

Science.gov (United States)

Waheeb, Nehal; Silikas, Nick; Watts, David

2012-10-01

To determine the effect of finishing and polishing time on the surface gloss of various resin-composites before and after simulated toothbrushing. Eight representative resin-composites (Ceram X mono, Ceram X duo, Tetric EvoCeram, Venus Diamond, EsteliteSigma Quick, Esthet.X HD, Filtek Supreme XT and Spectrum TPH) were used to prepare 80 disc-shaped (12 mm x 2 mm) specimens. The two step system Venus Supra was used for polishing the specimens for 3 minutes (Group A) and 10 minutes (Group B). All specimens were subjected to 16,000 cycles of simulated toothbrushing. The surface gloss was measured after polishing and after brushing using the gloss meter. Results were evaluated using one way ANOVA, two ways ANOVA and Dennett's post hoc test (P = 0.05). Group B (10-minute polishing) resulted in higher gloss values (GV) for all specimens compared to Group A (3 minutes). Also Group B showed better gloss retention compared to Group A after simulated toothbrushing. In each group, there was a significant difference between the polished composite resins (P gloss after the simulated toothbrushing.

The composition of readily available carbon sources produced by fermentation of fish faeces is affected by dietary protein:energy ratios

DEFF Research Database (Denmark)

Letelier-Gordo, Carlos Octavio; Larsen, Bodil Katrine; Dalsgaard, Johanne

2017-01-01

, 17, 19, 21 and 23 g/MJ) to rainbow trout (Oncorhynchus mykiss) on the production of volatile fatty acids (VFAs) and ethanol during 7 days fermentation of the produced fish faeces. The total yields of VFAs and ethanol obtained (expressed as chemical oxygen demand (COD)) ranged between 0.21–0.24 g...... of acetic and valeric acid. Changing the diet composition thus affects the composition of readily available carbon that can be derived from the faeces. This can be applied to enhance on-farm single sludge denitrification and reduce the need for adding external carbon sources such as e.g. methanol....

Does vagal nerve stimulation affect body composition and metabolism? Experimental study of a new potential technique in bariatric surgery.

Science.gov (United States)

Sobocki, Jacek; Fourtanier, Gilles; Estany, Joan; Otal, Phillipe

2006-02-01

It has been shown that vagal nerve stimulation (VNS) can affect body mass. The aim of this study was to evaluate effect of VNS on body mass, body composition, metabolic rate, and plasma leptin and IGF-I levels. Eight female pigs were included in the study. Under general anesthesia, a bipolar electrode was implanted on the anterior vagal nerve by laparoscopy. Group A was treated by VNS, and group B was the control. After 4 weeks, stimulation was discontinued in group A and started in group B. The following parameters were evaluated: body mass, body composition, metabolic rate, plasma leptin and IGF-1 levels and intramuscular fat content (IMF). VNS attenuated body weight gain (2.28 +/- 3.47 kg vs 14.04 +/- 6.75 kg; P = .0112, for stimulation and nonstimulation periods, respectively), backfat gain (0.04 +/- 0.26 mm vs 2.31 +/- 1.12 mm) and IMF gain (-3.76 +/- 6.06 mg/g MS vs 7.24 +/- 12.90 mg/g MS; P = .0281). VNS resulted in lower backfat depth/loin muscle area ratio (0.33 +/- 0.017 vs 0.38 +/- 0.35; P = .0476). Lower plasma IGF-I concentration was found after VNS (-3.67 +/- -11.55 ng/mL vs 9.86 +/- 10.74 ng/mL; P = .0312). No significant changes in other parameters were observed. VNS affects body weight mainly at the expense of body fat resources; however, metabolic rate is not affected.

Electrodialysis potential for fractionation of multicomponent aqueous solutions

Directory of Open Access Journals (Sweden)

Grzegorzek Martyna

2017-01-01

Full Text Available The paper aimed at the evaluation of the batch electrodialysis (ED run in the course of treatment and desalination of various aqueous mixtures containing both mineral (sodium fluoride, sodium chloride and organic substances (dyes or humic acids. The commercial ED stack (PCCell Bed equipped with standard anion-exchange and cation-exchange membranes or monovalent selective anion-exchange membranes was used. The ED experiments were performed at a constant current density (1.56 or 1.72 mA/cm2. The mechanism of ion migration as well as membrane deposition for variable solution composition and various membrane types was analyzed The calculated mass balance and electrical energy demand for each ED run were helpful in evaluating the membrane fouling intensity. It was found that the presence of organic substances in the treated solution had a minor impact on energy consumption, but rather strongly affected chloride flux. The extent of organics deposition was significantly lower for monovalent selective anion-exchange membranes than for classic anion-exchange membranes.

A numerical model for the solution of the Shallow Water equations in composite channels with movable bed

Science.gov (United States)

minatti, L.

2013-12-01

A finite volume model solving the shallow water equations coupled with the sediments continuity equation in composite channels with irregular geometry is presented. The model is essentially 1D but can handle composite cross-sections in which bedload transport is considered to occur inside the main channel only. This assumption is coherent with the observed behavior of rivers on short time scales where main channel areas exhibit more relevant morphological variations than overbanks. Furthermore, such a model allows a more precise prediction of thalweg elevation and cross section shape variations than fully 1D models where bedload transport is considered to occur uniformly over the entire cross section. The coupling of the equations describing water and sediments dynamics results in a hyperbolic non-conservative system that cannot be solved numerically with the use of a conservative scheme. Therefore, a path-conservative scheme, based on the approach proposed by Pares and Castro (2004) has been devised in order to account for the coupling with the sediments continuity equation and for the concurrent presence of bottom elevation and breadth variations of the cross section. In order to correctly compute numerical fluxes related to bedload transport in main channel areas, a special treatment of the equations is employed in the model. The resulting scheme is well balanced and fully coupled and can accurately model abrupt time variations of flow and bedload transport conditions in wide rivers, characterized by the presence of overbank areas that are less active than the main channel. The accuracy of the model has been first tested in fixed bed conditions by solving problems with a known analytical solution: in these tests the model proved to be able to handle shocks and supercritical flow conditions properly(see Fig. 01). A practical application of the model to the Ombrone river, southern Tuscany (Italy) is shown. The river has shown relevant morphological changes during

A nonlinear model for surface segregation and solute trapping during planar film growth

International Nuclear Information System (INIS)

Han, Xiaoying; Spencer, Brian J.

2007-01-01

Surface segregation and solute trapping during planar film growth is one of the important issues in molecular beam epitaxy, yet the study on surface composition has been largely restricted to experimental work. This paper introduces some mathematical models of surface composition during planar film growth. Analytical solutions are obtained for the surface composition during growth

Color stability of sealed composite resin restorative materials after ultraviolet artificial aging and immersion in staining solutions.

Science.gov (United States)

Catelan, Anderson; Briso, André Luiz Fraga; Sundfeld, Renato Hermann; Goiato, Marcelo Coelho; dos Santos, Paulo Henrique

2011-04-01

The color alteration of resin-based materials is one of the most common reasons to replace esthetic dental restorations. This study assessed the influence of surface sealant (Biscover) on the color stability of nanofilled (Supreme XT) and microhybrid (Vit-l-escence and Opallis) composite resins after artificial aging. One hundred disc-shaped (6 × 1.5 mm) specimens were made for each composite resin. After 24 hours, all specimens were polished and sealant was applied to 50 specimens of each material. Baseline color was measured according to the CIE L*a*b* system using a reflection spectrophotometer. Ten specimens of each group were aged for 252 h in an ultraviolet (UV)-accelerated aging chamber or immersed for 4 weeks in cola soft drink, orange juice, red wine staining solutions or distilled water as control. Color difference (ΔE) after aging was calculated based on the color coordinates before (baseline) and after aging/staining treatment. Data were analyzed with 2-way ANOVA and Fisher's test (α=.05). The results showed significant changes in color after artificial aging in all the groups (Paging, and the cola soft drink. The lowest values of ΔE were found for specimens stored in distilled water. All composite resins showed some color alteration after the aging methods. The surface sealant did not alter the color stability of the tested materials. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Effect of electron beam irradiation on the enzymatic degradation of composites based on biodegradable polymers and coconut fiber

Energy Technology Data Exchange (ETDEWEB)

Kodama, Yasko; Bardi, Marcelo Augusto Goncalves; Machado, Luci Diva Brocardo, E-mail: ykodama@ipen.b, E-mail: marcelo.bardi@usp.b, E-mail: lmachado@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rosa, Derval dos Santos, E-mail: derval.rosa@ufabc.edu.b [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil)

2011-07-01

The development of polymeric materials that are susceptible to microbiological degradation and that have properties similar to the conventional polymers would reduce waste deposit. Degradable plastics suffer significant change on chemical structure when submitted to specific environmental condition. PCL and PLLA have been extensively investigated due to their bio-assimilation and because they are considered as eco-friendly. So the degradation of PCL and PLLA homopolymers, PCL:PLLA 20:80 (w:w) blend and coconut fiber-modified composites were studied by means of their degradation under lipase enzyme from Pseudomonas cepacia. Non-irradiated and EB-irradiated samples at 50 kGy and 100 kGy were exposed during 24, 72, 120 and 168 hours to the enzyme-buffer solution and the retained mass of dried samples was accompanied over time. The results were compared to the not submitted to the enzyme solution samples. Degradation rate of PCL was higher than PLLA in the presence of Pseudomonas lipase. PLLA presence reduced PCL's enzymatic degradation in the PCL:PLLA 20:80 w:w blend. After 120 h exposure, blend mass loss variation approached pure PLLA behavior. Composites degradation behavior through time was similar to the blend. Values of retained mass for composites were superior to the blends suggesting that coconut fiber did not significantly degrade in the period of test. Degradation rate of 50 kGy-irradiated PCL slightly reduced, and it was observed increase of degradation rate of samples irradiated with 100 kGy, probably attributed to its crystallinity decrease. Degradation rate of irradiated composite was similar to the blend, suggesting that fiber presence did not affect significantly this parameter. Samples tested during 168 h were affected by the water absorption by PLLA or coconut fibers through time testing. Studied samples degraded accentuatedly in the enzyme presence and were not negatively affected by the radiation processing. (author)

Effect of electron beam irradiation on the enzymatic degradation of composites based on biodegradable polymers and coconut fiber

International Nuclear Information System (INIS)

Kodama, Yasko; Bardi, Marcelo Augusto Goncalves; Machado, Luci Diva Brocardo; Rosa, Derval dos Santos

2011-01-01

The development of polymeric materials that are susceptible to microbiological degradation and that have properties similar to the conventional polymers would reduce waste deposit. Degradable plastics suffer significant change on chemical structure when submitted to specific environmental condition. PCL and PLLA have been extensively investigated due to their bio-assimilation and because they are considered as eco-friendly. So the degradation of PCL and PLLA homopolymers, PCL:PLLA 20:80 (w:w) blend and coconut fiber-modified composites were studied by means of their degradation under lipase enzyme from Pseudomonas cepacia. Non-irradiated and EB-irradiated samples at 50 kGy and 100 kGy were exposed during 24, 72, 120 and 168 hours to the enzyme-buffer solution and the retained mass of dried samples was accompanied over time. The results were compared to the not submitted to the enzyme solution samples. Degradation rate of PCL was higher than PLLA in the presence of Pseudomonas lipase. PLLA presence reduced PCL's enzymatic degradation in the PCL:PLLA 20:80 w:w blend. After 120 h exposure, blend mass loss variation approached pure PLLA behavior. Composites degradation behavior through time was similar to the blend. Values of retained mass for composites were superior to the blends suggesting that coconut fiber did not significantly degrade in the period of test. Degradation rate of 50 kGy-irradiated PCL slightly reduced, and it was observed increase of degradation rate of samples irradiated with 100 kGy, probably attributed to its crystallinity decrease. Degradation rate of irradiated composite was similar to the blend, suggesting that fiber presence did not affect significantly this parameter. Samples tested during 168 h were affected by the water absorption by PLLA or coconut fibers through time testing. Studied samples degraded accentuatedly in the enzyme presence and were not negatively affected by the radiation processing. (author)

Electrodeposition and characterization of Ni-Mo-ZrO2 composite coatings

Science.gov (United States)

Laszczyńska, A.; Winiarski, J.; Szczygieł, B.; Szczygieł, I.

2016-04-01

Ni-Mo-ZrO2 composite coatings were produced by electrodeposition technique from citrate electrolytes containing dispersed ZrO2 nanopowder. The influence of deposition parameters i.e. concentration of molybdate and ZrO2 nanoparticles in the electrolyte, bath pH and deposition current density on the composition and surface morphology of the coating has been investigated. The structure, microhardness and corrosion properties of Ni-Mo-ZrO2 composites with different molybdenum and ZrO2 content have been also examined. It was found that ZrO2 content in the deposit is increased by rising the nanoparticles concentration in the plating solution up to 20 g dm-3. An increase in molybdate concentration in the electrolyte affects negatively the amount of codeposited ZrO2 nanoparticles. The correlation between the deposition current efficiency and ZrO2 content in the composite coating has been also observed. A decrease in deposition current efficiency leads to deposition of Ni-Mo-ZrO2 composite with low nanoparticles content. This may be explained by formation of higher amounts of gas bubbles on the cathode surface, which prevent the adsorption of ZrO2 nanoparticles on the growing deposit. The XRD analysis revealed that all the studied Ni-Mo-ZrO2 coatings were composed of a single, nanocrystalline phase with FCC structure. It was found that the incorporation of ZrO2 nanoparticles into Ni-Mo alloy matrix affects positively the microhardness and also slightly improves the corrosion properties of Ni-Mo alloy coating.

The Influence of the Addition of Polyacrylic Hydrogel on the Content of Proteins, Minerals and Trace Elements in Milk Protein Solutions

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Aleksandar Ž. Kostić

2014-01-01

Full Text Available Solutions of milk protein concentrate, whey protein concentrate and bovine serum albumin (BSA were treated with polyacrylic hydrogel to establish whether the hydrogel could be used for decontamination of heavy metal ions from milk protein-based products. The obtained results indicated that swelling of hydrogel in these solutions had different effects on their mineral, trace element and total protein content. Total protein and phosphorus content increased in milk protein concentrate and whey protein concentrate solutions after swelling of hydrogel without changes in their protein compositions. On the other hand, the protein content in BSA solution decreased after swelling. The content of Na did not change in milk protein concentrate solution, whereas it significantly increased in whey protein concentrate solution after hydrogel swelling. The content of Ca and Mg was reduced after the swelling in milk protein concentrate and whey protein concentrate solutions for 20.3–63.4 %, depending on the analysed sample and the mineral. The content of Zn did not change during swelling, whereas the content of Fe, Cu, Mn, Ni and Pb significantly decreased after hydrogel swelling in all analysed samples. According to the obtained results, the addition of polyacrylic hydrogel to milk and whey protein concentrate solutions can significantly decrease the content of heavy metal ions without affecting their protein composition. Therefore, this work could be useful in developing a new technological process for heavy metal purification of milk protein-based products.

Biochemical composition of fluids for amnioinfusion during fetoscopy.

Science.gov (United States)

Adama van Scheltema, P N; In't Anker, P S; Vereecken, A; Vandenbussche, F P H A; Deprest, J A; Devlieger, R

2008-01-01

To evaluate which of the commercially available solutions is best suited for amnioinfusion during fetoscopy, based on resemblance with the biochemical properties of amniotic fluid. Amniotic fluid samples from 10 pregnancies were studied. Specimens were obtained from 5 pathologic pregnancies (of which 3 were complicated by polyhydramnios) and 5 uncomplicated pregnancies. The concentrations of sodium, potassium, chloride, bicarbonate, calcium, glucose, osmolality, pH, total protein content and albumin were determined in each sample. A literature search (PubMed, Embase) was performed to identify commercially available fluids used for amnioinfusion in clinical practice. The composition of these infusion solutions was compared to the amniotic fluid samples mentioned above. We identified two different electrolyte solutions used in clinical practice for amnioinfusion. We identified four additional commercially available solutions that could potentially be used for amnioinfusion. Most of these infusion solutions differ considerably from midtrimester amniotic fluid samples both in electrolyte composition and pH, with the most striking difference in the latter. Lactated Ringer's solution approximates amniotic fluid the closest for both electrolyte composition and pH. This infusion solution seems to be the most suitable choice for amnioinfusion during fetoscopy. (c) 2008 S. Karger AG, Basel.

Analysis on the factors affecting the preparation of TIO2-ADUN composite sol by sol-gel method

International Nuclear Information System (INIS)

Wang Hui; Yin Rongcai; Liu Jinhong

2010-01-01

With C 2 H 2 O 5 and water as solvent and TBT as precursor and HNO 3 as the activator and valorize, the process for preparing TiO 2 -ADUN composite Sol method was studied. The influence of different reaction conditions on Sol-Gel time was analyzed in this study. The optimal reaction condition are: reaction temperature 20-25 degree C; pH value of reaction mixture 2-5; HNO 3 value of reaction mixture 0.3-0.5 ml; molar rations of alcohol to TBT 10, of water to TBT 2-3, respectively. A concentrated ADUN solution with Ti Sol , urea, water as additive is dispersed into uniform which are prepared by external mlii. (authors)

Ti2Al(C, N) Solid Solution Reinforcing TiAl-Based Composites: Evolution of a Core-Shell Structure, Interfaces, and Mechanical Properties.

Science.gov (United States)

Song, Xiaojie; Cui, Hongzhi; Han, Ye; Ding, Lei; Song, Qiang

2018-05-16

In this work, Ti 2 Al(C, N) solid solution with lamellar structure-enhanced TiAl matrix composites was synthesized by vacuum arc melting, using bulk g-C 3 N 4 , Ti, and Al powders as raw materials. The phases, microstructures, interfaces, and mechanical properties were investigated. MAX phase of Ti 2 Al(C, N) solid solution with lamellar structure was formed. During the melting process, first, C 3 N 4 reacted with Ti to form Ti(C, N) by Ti + C 3 N 4 → Ti(C, N). Then Ti 2 Al(C, N) was formed by a peritectic reaction of TiAl(l) + Ti(C, N)(s) → Ti 2 Al(C, N). C 3 N 4 is the single reactant that provides C and N simultaneously to final product of Ti 2 Al(C, N). The interfaces of TiAl//Ti 2 Al(C, N) and Ti 2 Al(C, N)//Ti(C, N) display perfect orientation relationships with low misfit values. The microhardness, compressive strength, and strain of best-performing TiAl-10 mol % Ti 2 Al(C, N) composite were improved by 45%, 55.7%, and 50% compared with the TiAl alloy, respectively. Uniformly distributed Ti 2 Al(C, N) and unreacted Ti(C, N) particles contributed to the grain refinement and reinforcement of the TiAl matrix. Laminated tearing, particle pull-out, and the crack-arresting of Ti 2 Al(C, N) are crucial for the improvement in compressive strength and plasticity of the composites.

Automatically varying the composition of a mixed refrigerant solution for single mixed refrigerant LNG (liquefied natural gas) process at changing working conditions

International Nuclear Information System (INIS)

Xu, Xiongwen; Liu, Jinping; Cao, Le; Pang, Weiqiang

2014-01-01

The SMR (single mixed refrigerant) process is widely used in the small- and medium-scale liquefaction of NG (natural gas). Operating the MR (mixed-refrigerant) process outside of the design specifications is difficult but essential to save energy. Nevertheless, it is difficult to realize because the process needs to alter the working refrigerant composition. To address this challenge, this study investigated the performance diagnosis mechanism for SMR process. A control strategy was then proposed to control the changes in working refrigerant composition under different working conditions. This strategy separates the working refrigerant flow in the SMR process into three flows through two phase separators before it flows into the cold box. The first liquid flow is rich in the high-temperature component (isopentane). The second liquid flow is rich in the middle-temperature components (ethylene and propane), and the gas flow is rich in the low-temperature components (nitrogen and methane). By adjusting the flow rates, it is easy to decouple the control variables and automate the system. Finally, this approach was validated by process simulation and shown to be highly adaptive and exergy efficient in response to changing working conditions. - Highlights: • The performance diagnosis mechanism of SMR LNG process is studied. • A measure to automatically change the operation composition as per the working conditions is proposed for SMR process. • SMR process simulation is performed to verify the validity of the control solution. • The control solution notably improves the energy efficiency of SMR process at changing working condition

Chitosan composite hydrogels reinforced with natural clay nanotubes.

Science.gov (United States)

Huang, Biao; Liu, Mingxian; Zhou, Changren

2017-11-01

Here, chitosan composites hydrogels were prepared by addition of halloysite nanotubes (HNTs) in the chitosan KOH/LiOH/urea solution. The raw chitosan and chitosan/HNTs composite hydrogels were obtained by heat treatment at 60°C for 8h and then regeneration in ethanol solution. The viscosity of the composite solution is increased with HNTs content. The Fourier transform infrared spectroscopy (FT-IR) shows that the hydrogen bonds interactions exist between the HNTs and the chitosan. X-ray diffraction (XRD) results show that the crystal structure of HNT is not changed in the composite hydrogels. The compressive property test and storage modulus determination show that the mechanical properties and anti-deformation ability of the composite hydrogel significantly increase owing to the reinforcing effect of HNTs. The composites hydrogel with 66.7% HNTs can undergo 7 times compression cycles without breaking with compressive strength of 0.71MPa at 70% deformation, while pure chitosan hydrogel is broken after bearing 5 compression cycles with compressive strength of 0.14MPa and a maximum deformation of 59%. A porous structure with pore size of 100-500μm is found in the composite hydrogels by scanning electron microscopy (SEM), and the pore size and the swelling ratio in NaCl solution decrease by the addition of HNTs and the immersing of ethanol. Chitosan/HNTs composite hydrogels show low cytotoxicity towards MC3T3-E1 cells. Also, the composite hydrogels show a maximum drug entrapment efficiency of 45.7% for doxorubicin (DOX) which is much higher than that of pure chitosan hydrogel (27.5%). All the results illustrate that the chitosan/HNTs composite hydrogels show promising applications as biomaterials. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of finishing and polishing on the color stability of a composite resin immersed in staining solutions

Directory of Open Access Journals (Sweden)

Maiara Justo Polli

2015-01-01

Full Text Available Objective: To evaluate the influence of finishing/polishing methods and staining solutions using different immersion periods on the color stability of a microhybrid composite resin. Materials and Methods: Ninety specimens were fabricated using a stainless steel mold and polyester strips. The samples were randomly divided into five groups according to the finishing and polishing performed: Control group (no surface treatment was performed, Diamond Pro group, Diamond burs group, Enhance group, and SiC paper group. After finishing and polishing, six samples from each group were immersed in coffee, red wine, or water for 30 days. The color measurements were obtained using digital photography before immersion and after 7, 15, and 30 days of immersion. The red, green, and blue values provided by the Adobe Photoshop software were converted into CIELab values. A three-way analysis of variance and Tukey's test were used for statistical analysis (P ≤ 0.05. Results: The finishing and polishing methods, staining solutions, immersion times, and their interaction had statistically significant effects on the color change (P = 0.00. Coffee and red wine caused intense staining. Among the polishing methods, the highest color change value was observed in the control group (P < 0.05 and the Diamond Pro disks provided the most stain-resistant surfaces (P ≤ 0.05. Conclusion: The finishing and polishing method, staining solution, and immersion time influences the color stability. Finishing and polishing should be applied to obtain a more stain-resistant surface.

Strong work-hardening behavior induced by the solid solution strengthening of dendrites in TiZr-based bulk metallic glass matrix composites

Energy Technology Data Exchange (ETDEWEB)

Ma, D.Q. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Jiao, W.T. [College of Education, Hebei Normal University of Science and Technology, Qinhuangdao 066004 (China); Zhang, Y.F. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Hebei Vocational and Technical College of Building Materials, Qinhuangdao 066004 (China); Wang, B.A.; Li, J.; Zhang, X.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Ma, M.Z., E-mail: mz550509@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, R.P. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

2015-03-05

Highlights: • Hardness of dendrite of TiZr-based BMGMCs increases. • Strong work-hardening behavior is obtained after solid solution strengthening. • Lattice distortions of dendrite suffering from rapid cooling are detected. - Abstract: A series of TiZr-based bulk metallic glass matrix composites (BMGMCs) with distinguished mechanical properties are successfully fabricated by adding different volume fractions of Ta (Ti{sub 38.8}Zr{sub 28.8}Cu{sub 6.2}Be{sub 16.2}Nb{sub 10} as the basic composition, denoted as Ta{sub 0.0}–Ta{sub 8.0}). Along with the growth of precipitated phase, typical dendritic morphology is fully developed in the TiZr-based BMGMCs of Ta{sub 8.0}. Energy-dispersive spectrometry analysis of the dendrites and glass matrix indicates that the metallic elements of Nb and Ta should preferentially form solid solution into dendrites. The chaotic structure of high-temperature precipitate phase is trapped down by the rapid cooling of the copper-mould. The detected lattice distortions in the dendrites are attributed to the strong solid solution strengthening of the metallic elements of Ti, Zr, Nb, and Ta. These lattice distortions increase the resistance of the dislocation motion and pin the dislocations, thus the strength and hardness of dendrite increase. Dendrites create a strong barrier for the shear band propagation and generate multiple shear bands after solid solution strengthening, thereby providing the TiZr-based BMGMCs with greatly improved capacity to sustain plastic deformation and resistance to brittle fracture. Thus, the TiZr-based BMGMCs possess distinguished work-hardening capability. Among these TiZr-based BMGMCs, the sample Ta{sub 0.5} possesses the largest plastic strain (ε{sub p}) at 20.3% and ultimate strength (σ{sub max}) of 2613 MPa during compressive loading. In addition, the sample of Ta{sub 0.5} exhibits work-hardening up to an ultrahigh tensile strength of 1680 MPa during the tensile process, and then progressively

Kinetic Studies For the Removal of UO22+ and Pb2+ Ions From Aqueous Solution Using Zirconia Composite Material

International Nuclear Information System (INIS)

Sharaf El-Deen, G.E.

2008-01-01

Zirconia composite material was chemically synthesized previously and prepared by applying the sol-gel polymeric route using MgO as a stabilizer. The prepared composite material was characterized using various techniques: x-ray fluorescence (XRF), scanning electron microscope (SEM), differential thermal analysis and thermogravimetric analysis (DTA-TG), x-ray diffraction (XRD) and surface area using the BET-method. The sorption removal of UO 2 2+ and Pb 2+ ions from aqueous waste solution by zirconia composite material using batch technique was investigated. The sorption was carried out as a function of ph, particle size, shaking time and temperature. In this work, a comparison of kinetic models applied to the sorption process of each ion was evaluated for the pseudo first-order, the pseudo second-order, intra particle diffusion and homogeneous particle diffusion kinetic models, respectively. The results showed that the homogeneous particle diffusion model (HPDM) best correlate the experimental rate data and the numerical values of the rate constants and particle diffusion coefficients were determined from the graphical representation of the proposed models. Activation energy (Ε a ) and thermodynamic parameters of free energy (δ G * ), enthalpy (δ H * ) and entropy (δ S * ) of activation were also computed from the linearized form of Arrhenius equation

Self-Assembled Carbon-Polyoxometalate Composites for Electrochemical Capacitors

Science.gov (United States)

Genovese, Matthew

The development of high performance yet cost effective energy storage devices is critical for enabling the growth of important emerging sectors from the internet of things to grid integration of renewable energy. Material costs are by far the largest contributor to the overall cost of energy storage devices and thus research into cost effective energy storage materials will play an important role in developing technology to meet real world storage demands. In this thesis, low cost high performance composite electrode materials for supercapacitors (SCs) have been developed through the surface modification of electrochemically double layer capacitive (EDLC) carbon substrates with pseudocapacitive Polyoxometalates (POMs). Significant fundamental contributions have been made to the understanding of all components of the composite electrode including the POM active layer, cation linker, and carbon substrate. The interaction of different POM chemistries in solution has been studied to elucidate the novel ways in which these molecules combine and the mechanism underlying this combination. A more thorough understanding regarding the cation linker's role in electrode fabrication has been developed through examining the linker properties which most strongly affect electrode performance. The development of porosity in biomass derived carbon materials has also been examined leading to important insights regarding the effect of substrate porosity on POM modification and electrochemical properties. These fundamental contributions enabled the design and performance optimization of POM-carbon composite SC electrodes. Understanding how POMs combine in solution, allowed for the development of mixed POM molecular coatings with tunable electrochemical properties. These molecular coatings were used to modify low cost biomass derived carbon substrates that had been structurally optimized to accommodate POM molecules. The resulting electrode composites utilizing low cost materials

Factors Affecting Dissolution Resistance of AC Anodizing Al in Sodium Carbonate Solution

International Nuclear Information System (INIS)

Abou-Krisha, M.

2001-01-01

Studies were performed to determine the effect of different factors on the properties and so the dissolution resistance of the anodic film of Al. Conductance and thermometric measurements were applied to evaluate the dissolution rate. The effect of applied AC voltage concentration of sodium carbonate solution, the anodization time and the temperature of sodium carbonate solutions show a parallel increase in the dissolution resistance of studied Al in hydrochloride acid. The results show that films formed by sodium carbonate solution were of porous type and have pronounced high resistance. Scanning electron microscope and x-ray diffraction further examined the films. The anodic and cathodic behavior and the effect of the scanning rate on the polarization of Al in sodium carbonate solution were studied. The regression analysis was applied to all results. (Author)

Green preparation of a novel red mud@carbon composite and its application for adsorption of 2,4-dichlorophenoxyacetic acid from aqueous solution.

Science.gov (United States)

Kazak, Omer; Eker, Yasin Ramazan; Akin, Ilker; Bingol, Haluk; Tor, Ali

2017-10-01

This study reports the eco-friendly preparation of a novel composite material consisting of red mud and carbon spheres, denoted as red mud@C composite, and its application for the removal of 2,4-dichlorophenoxyacetic acid herbicide (2,4-D) from aqueous solution. The preparation route has a green approach because it follows the low-energy consuming one-step hydrothermal process by using starch as a renewable carbon precursor and red mud as a waste from aluminum production industry. Characterization of the red mud@C composite was performed by FT-IR, TGA, SEM, TEM, BET, XRD, and Raman microscopy analyses. The batch adsorption studies revealed that the red mud@C composite has higher 2,4-D adsorption efficiency than those of the red mud and the naked carbon spheres. The maximum removal at initial pH of 3.0 is explained by considering the pKa of 2,4-D and pH of point of zero charge (pH pzc ) of the composite material. The adsorption equilibrium time was 60 min, which followed the pseudo-second-order kinetic model together with intra-particle diffusion model. The isotherm analysis indicated that Freundlich isotherm model better represented the adsorption data, with isotherm parameters of k [15.849 (mg/g) (mg/L) -1/n ] and n (2.985). The prepared composite is reusable at least 5 cycles of adsorption-desorption with no significant decrease in the adsorption capacity.

Non-Catalytic Self Healing Composite Material Solution, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Fiber reinforce polymer (FRP) composite materials are seeing increasing use in the construction of a wide variety of aerospace structures. However, uncertainties...

Textile Dye Removal from Aqueous Solution using Modified Graphite Waste/Lanthanum/Chitosan Composite

Science.gov (United States)

Kusrini, E.; Wicaksono, B.; Yulizar, Y.; Prasetyanto, EA; Gunawan, C.

2018-03-01

We investigated various pre-treatment processes of graphite waste using thermal, mechanical and chemical methods. The aim of this work is to study the performance of modified graphite waste/lanthanum/chitosan composite (MG) as adsorbent for textile dye removal from aqueous solution. Effect of graphite waste resources, adsorbent size and lanthanum concentration on the dye removal were studied in batch experiments. Selectivity of MG was also investigated. Pre-heated graphite waste (NMG) was conducted at 80°C for 1 h, followed by mechanical crushing of the resultant graphite to 75 μm particle size, giving adsorption performance of ˜58%, ˜67%, ˜93% and ˜98% of the model dye rhodamine B (concentration determined by UV-vis spectroscopy at 554 nm), methyl orange (464 nm), methylene blue (664 nm) and methyl violet (580 nm), respectively from aqueous solution. For this process, the system required less than ˜5 min for adsorbent material to be completely saturated with the adsorbate. Further chemical modification of the pre-treated graphite waste (MG) with lanthanum (0.01 – V 0.03 M) and chitosan (0.5% w/w) did not improve the performance of dye adsorption. Under comparable experimental conditions, as those of the ‘thermal-mechanical-pre-treated-only’ (NMG), modification of graphite waste (MG) with 0.03 M lanthanum and 0.5% w/w chitosan resulted in ˜14%, ˜47%, ˜72% and ˜85% adsorption of rhodamine B, methyl orange, methylene blue and methyl violet, respectively. Selective adsorption of methylene blue at most to ˜79%, followed by methyl orange, methyl violet and rhodamine B with adsorption efficiency ˜67, ˜38, and ˜9% sequentially using MG with 0.03 M lanthanum and 0.5% w/w chitosan.

Osmolality, temperature, and membrane lipid composition modulate the activity of betaine transporter BetP in Corynebacterium glutamicum

DEFF Research Database (Denmark)

Ozcan, Nuran; Ejsing, Christer S.; Shevchenko, Andrej

2007-01-01

The gram-positive soil bacterium Corynebacterium glutamicum, a major amino acid-producing microorganism in biotechnology, is equipped with several osmoregulated uptake systems for compatible solutes, which is relevant for the physiological response to osmotic stress. The most significant carrier......P activity. We further correlated the change in BetP regulation properties in cells grown at different temperatures to changes in the lipid composition of the plasma membrane. For this purpose, the glycerophospholipidome of C. glutamicum grown at different temperatures was analyzed by mass spectrometry using...... quantitative multiple precursor ion scanning. The molecular composition of glycerophospholipids was strongly affected by the growth temperature. The modulating influence of membrane lipid composition on BetP function was further corroborated by studying the influence of artificial modulation of membrane...

Probabilistic Compositional Models: solution of an equivalence problem

Czech Academy of Sciences Publication Activity Database

Kratochvíl, Václav

2013-01-01

Roč. 54, č. 5 (2013), s. 590-601 ISSN 0888-613X R&D Projects: GA ČR GA13-20012S Institutional support: RVO:67985556 Keywords : Probabilistic model * Compositional model * Independence * Equivalence Subject RIV: BA - General Mathematics Impact factor: 1.977, year: 2013 http://library.utia.cas.cz/separaty/2013/MTR/kratochvil-0391079.pdf

Frequent Prescribed Burning as a Long-term Practice in Longleaf Pine Forests Does Not Affect Detrital Chemical Composition.

Science.gov (United States)

Coates, T Adam; Chow, Alex T; Hagan, Donald L; Wang, G Geoff; Bridges, William C; Dozier, James H

2017-09-01

The O horizon, or detrital layer, of forest soils is linked to long-term forest productivity and health. Fuel reduction techniques, such as prescribed fire, can alter the thickness and composition of this essential ecosystem component. Developing an understanding of the changes in the chemical composition of forest detritus due to prescribed fire is essential for forest managers and stakeholders seeking sustainable, resilient, and productive ecosystems. In this study, we evaluated fuel quantity, fuel structure, and detrital chemical composition in longleaf pine ( Miller) forests that have been frequently burned for the last 40 yr at the Tom Yawkey Wildlife Center in Georgetown, SC. Our results suggest that frequent prescribed fire reduces forest fuel quantity ( burned detritus. Our burning activities varied in the short term, consisting of annual dormant, annual growing, and biennial dormant season burns. Seasonal distinctions were present for fuel quantity and vertical fuel structure, but these differences were not noted for the benzene/phenol ratio. These results are significant as more managers consider burning existing longleaf stands while determining effective management practices for longleaf stands yet to be established. Managers of such stands can be confident that frequent, low-intensity, low-severity prescribed burns in longleaf pine forests do little to affect the long-term chemical composition of forest detritus. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Generalized solution of design optimization and failure analysis of composite drive shaft

Energy Technology Data Exchange (ETDEWEB)

Kollipalli, K.; Shivaramakrishna, K.V.S.; Prabhakaran, R.T.D. [Birla Institute of Technology and Science, Goa (India)

2012-07-01

Composites have an edge over conventional metals like steel and aluminum due to higher stiffness-to-weight ratio and strength-to-weight ratio. Due to these advantages, composites can bring out a revolutionary change in materials used in automotive engineering, as weight savings has positive impacts on other attributes like fuel economy and possible noise, vibration and harshness (NVH). In this paper, the drive line system of an automotive system is targeted for use of composites by keeping constraints in view such as such as torque transmission, torsional buckling load and fundamental natural frequency. Composite drive shafts made of three different composites ('HM Carbon/HS Carbon/E-glass'-epoxy) was modeled using Catia V5R16 CPD workbench and a finite element analysis with boundary conditions, fiber orientation and stacking sequence was performed using ANSYS Composite module. Results obtained were compared to theoretical results and were found to be accurate and in the limits. This paper also speaks on drive shaft modeling and analysis generalization i.e., changes in stacking sequence in the future can be incorporated directly into ANSYS model without modeling it again in Catia. Hence the base model and analysis method made up in this analysis generalization facilitated by CAD/CAE can be used to carry out any composite shaft design optimization process. (Author)

Formation of Silica-Lysozyme Composites Through Co-Precipitation and Adsorption

Directory of Open Access Journals (Sweden)

Daniela B. van den Heuvel

2018-04-01

Full Text Available Interactions between silica and proteins are crucial for the formation of biosilica and the production of novel functional hybrid materials for a range of industrial applications. The proteins control both precipitation pathway and the properties of the resulting silica–organic composites. Here, we present data on the formation of silica–lysozyme composites through two different synthesis approaches (co-precipitation vs. adsorption and show that the chemical and structural properties of these composites, when analyzed using a combination of synchrotron-based scattering (total scattering and small-angle X-ray scattering, spectroscopic, electron microscopy, and potentiometric methods vary dramatically. We document that while lysozyme was not incorporated into nor did its presence alter the molecular structure of silica, it strongly enhanced the aggregation of silica particles due to electrostatic and potentially hydrophobic interactions, leading to the formation of composites with characteristics differing from pure silica. The differences increased with increasing lysozyme content for both synthesis approaches. Yet, the absolute changes differ substantially between the two sets of composites, as lysozyme did not just affect aggregation during co-precipitation but also particle growth and likely polymerization during co-precipitation. Our results improve the fundamental understanding of how organic macromolecules interact with dissolved and nanoparticulate silica and how these interactions control the formation pathway of silica–organic composites from sodium silicate solutions, a widely available and cheap starting material.

Formation of Silica-Lysozyme Composites Through Co-Precipitation and Adsorption

Science.gov (United States)

van den Heuvel, Daniela B.; Stawski, Tomasz M.; Tobler, Dominique J.; Wirth, Richard; Peacock, Caroline L.; Benning, Liane G.

2018-04-01

Interactions between silica and proteins are crucial for the formation of biosilica and the production of novel functional hybrid materials for a range of industrial applications. The proteins control both precipitation pathway and the properties of the resulting silica-organic composites. Here we present data on the formation of silica-lysozyme composites through two different synthesis approaches (co-precipitation vs. adsorption) and show that the chemical and structural properties of these composites, when analyzed using a combination of synchrotron-based scattering (total scattering and SAXS), spectroscopic, electron microscopy and potentiometric methods vary dramatically. We document that while lysozyme was not incorporated into nor did its presence alter the molecular structure of silica, it strongly enhanced the aggregation of silica particles due to electrostatic and potentially hydrophobic interactions, leading to the formation of composites with characteristics differing from pure silica. The differences increased with increasing lysozyme content for both synthesis approaches. Yet, the absolute changes differ substantially between the two sets of composites, as lysozyme did not just affect aggregation during co-precipitation but also particle growth and likely polymerization during co-precipitation. Our results improve the fundamental understanding of how organic macromolecules interact with dissolved and nanoparticulate silica and how these interactions control the formation pathway of silica-organic composites from sodium silicate solutions, a widely available and cheap starting material.

Synthesis and characterization of polyaniline/activated carbon composites and preparation of conductive films

International Nuclear Information System (INIS)

Zengin, Huseyin; Kalayci, Guellue

2010-01-01

Polyaniline was synthesized via polyaniline/activated carbon (PANI/AC) composites by in situ polymerization and ex situ solution mixing. PANI and PANI/AC composite films were prepared by drop-by-drop and spin coating methods. The electrical conductivities of HCl doped PANI film and PANI/AC composite films were measured according to the standard four-point-probe technique. The composite films exhibited an increase in electrical conductivity over neat PANI. PANI and PANI/AC composites were investigated by spectroscopic methods including UV-vis, FTIR and photoluminescence. UV-vis and FTIR studies showed that AC particles affect the quinoid units along the polymer backbone and indicate strong interactions between AC particles and quinoidal sites of PANI. The photoluminescence properties of PANI and PANI/AC composites were studied and the photoluminescence intensity of PANI/AC composites was higher than that of neat PANI. The increase of conductivity of PANI/AC composites may be partially due to the doping or impurity effect of AC, where the AC competes with chloride ions. The amount of weight loss and the thermostability of PANI and PANI/AC composites were determined from thermogravimetric analysis. The morphology of particles and films were examined by a scanning electron microscope (SEM). SEM measurements indicated that the AC particles were well dispersed and isolated in composite films.

Preparation of fullerene/glass composites

Science.gov (United States)

Mattes, Benjamin R.; McBranch, Duncan W.; Robinson, Jeanne M.; Koskelo, Aaron C.; Love, Steven P.

1995-01-01

Synthesis of fullerene/glass composites. A direct method for preparing solid solutions of C.sub.60 in silicon dioxide (SiO.sub.2) glass matrices by means of sol-gel chemistry is described. In order to produce highly concentrated fullerene-sol-gel-composites it is necessary to increase the solubility of these "guests" in a delivery solvent which is compatible with the starter sol (receiving solvent). Sonication results in aggregate disruption by treatment with high frequency sound waves, thereby accelerating the rate of hydrolysis of the alkoxide precursor, and the solution process for the C.sub.60. Depending upon the preparative procedure, C.sub.60 dispersed within the glass matrix as microcrystalline domains, or dispersed as true molecular solutions of C.sub.60 in a solid glass matrix, is generated by the present method.

Fabrication of compact and stable perovskite films with optimized precursor composition in the fast-growing procedure

Energy Technology Data Exchange (ETDEWEB)

Liu, Tanghao; Zhou, Yuanyuan; Hu, Qin; Chen, Ke; Zhang, Yifei; Yang, Wenqiang; Wu, Jiang; Ye, Fengjun; Luo, Deying; Zhu, Kai; Padture, Nitin P.; Liu, Feng; Russell, Thomas; Zhu, Rui; Gong, Qihuang

2017-06-02

The fast-growing procedure (FGP) provides a simple, high-yield and lead (Pb)-release free method to prepare perovskite films. In the FGP, the ultra-dilute perovskite precursor solution is drop-cast onto a hot (~240 degrees C) substrate, where a perovskite film grows immediately accompanied by the rapid evaporation of the host solvent. In this process, all the raw materials in the precursor solution are deposited into the final perovskite film. The potential pollution caused by Pb can be significantly reduced. Properties of the FGP-processed perovskite films can be modulated by the precursor composition. While CH3NH3Cl (MACl) affects the crystallization process and leads to full surface coverage, CH(NH2)2I (FAI) enhances the thermal stability of the film. Based on the optimized precursor composition of PbI2(1-x)FAI xMACl, x=0.75, FGP-processed planar heterojunction perovskite solar cells exhibit power conversion efficiencies (PCEs) exceeding 15% with suppressed hysteresis and excellent reproducibility.

Effect of Mineral Composition on Thermoluminescence Analysis of Irradiated Garlics

International Nuclear Information System (INIS)

Sookkasem, Atitaya; Wanwisa, Sudprasert; Vitittheeranon, Arag

2009-07-01

Full text: Thermoluminescence (TL) is one of the most popular techniques used for identification of irradiated foods such as spices, herbs and dried fruits in accordance with the Codex Standards. TL analysis is based on the determination of TL of adhering or contaminating minerals in foods. This research aimed to study the effect of mineral composition on the TL intensity. The composited minerals were extracted from 3 types of non-irradiated and irradiated garlic powders by sodium polytungstate solution. X-ray diffraction (XRD) spectroscopy was employed to investigate the type and amount of minerals present in garlic powders. TL of separated minerals were analysed using a Harshaw 4500 TL reader. The results showed that the mineral composition of garlic powders was mainly quartz of varying amounts depending on types of garlics. The TL intensity linearly increased with the amount of quartz present in the samples. It can be concluded that the amount of minerals affect the TL intensity which might influence the identification of irradiated tretment of garlics by thermoluminescence

Effect of fiber content on the thermal conductivity and dielectric constant of hair fiber reinforced epoxy composite

Science.gov (United States)

Prasad Nanda, Bishnu; Satapathy, Alok

2018-03-01

This paper reports on the dielectric and thermal properties of hair fibers reinforced epoxy composites. Hair is an important part of human body which also offers protection to the human body. It is also viewed as a biological waste which is responsible for creating environmental pollution due to its low decomposition rate. But at the same time it has unique microstructural, mechanical and thermal properties. In the present work, epoxy composites are made by solution casting method with different proportions of short hair fiber (SHF). Effects of fiber content on the thermal conductivity and dielectric constant of epoxy resin are studied. Thermal conductivities of the composites are obtained using a UnithermTM Model 2022 tester. An HIOKI-3532-50 Hi Tester Elsier Analyzer is used for measuring the capacitance of the epoxy-SHF composite, from which dielectric constant (Dk) of the composite are calculated. A reduction in thermal conductivity of the composite is noticed with the increase in wt. % of fiber. The dielectric constant value of the composites also found to be significantly affected by the fiber content.

Consolidation Theory for a Stone Column Composite Foundation under Multistage Loading

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Shenggen Huang

2016-01-01

Full Text Available The consolidation theories considering instant load cannot fully reveal the consolidation mechanism of a stone column composite foundation used in the expressway embankments due to the time effect of loading; that is, the expressway embankments are often constructed in several stages for a long time. Meanwhile, owing to the special property that the pile-soil stress ratio is larger than 1, the consolidation theory for sand drain well foundation cannot be used directly in the consolidation analysis of stone column composite foundation. Based on the principle that the vertical load applied on the composite foundation is shared by the stone column and the surrounding soil, the governing solutions for the stone column composite foundation under a multistage load are established. By virtue of the separation of variables, the corresponding solutions of degree of consolidation for loading stage and maintaining load stage are derived separately. According to the Carrillo theorem, the solution for the average total degree of consolidation of entire composite foundation is also obtained. Finally, the reasonableness of the present solution has been verified by comparing the consolidation curve calculated by the present solution with that measured by site test.

Corrosion behavior and pitting susceptibility of in-situ Ti-based metallic glass matrix composites in 3.5 wt.% NaCl solutions

Science.gov (United States)

Xu, K. K.; Lan, A. D.; Yang, H. J.; Han, P. D.; Qiao, J. W.

2017-11-01

The Ti62Zr12V13Cu4Be9, Ti58Zr16V10Cu4Be12, Ti46Zr20V12Cu5Be17, and Ti40Zr24V12Cu5Be19 metallic glass matrix composites (MGMCs) were prepared by copper mould casting. The corrosion resistance and the pitting susceptibility of Ti-based MGMCs were tested on their cross-sectional areas in 3.5 wt.% NaCl solutions by potentiodynamic polarization measurements. The composites with lower Ti contents (Ti40Zr24V12Cu5Be19 and Ti46Zr20V12Cu5Be17) exhibit a low resistance to the chloride induced pitting and local corrosion. The preferential dissolution of amorphous matrix is explained by the high chemical reactivity of beryllium element compared to that of stable dendrites and by the detected lower Ti and V contents. However, fairly good passivity was found in the composite with higher Ti contents (Ti62Zr12V13Cu4Be9). XPS measurements revealed that protective Ti-enriched oxide film was formed on the composite surface, additionally, lower content of beryllium element in amorphous matrix hinder the selective corrosion of amorphous matrix. The assessment of experimental observation leads to a proposed corrosion mechanism involving selective dissolution of amorphous matrix and chloride induced pitting process.

Solution chemistry and separation of metal ions in leached solution

International Nuclear Information System (INIS)

Shibata, J.

1991-01-01

The method to presume a dissolved state of metal ions in an aqueous solution and the technology to separate and concentrate metal ions in a leached solution are described in this paper. It is very important for the separation of metal ions to know the dissolved state of metal ions. If we know the composition of an aqueous solution and the stability constants of metal-ligand complexes, we can calculate and estimate the concentration of each species in the solution. Then, we can decide the policy to separate and concentrate metal ions. There are several methods for separation and purification; hydroxide precipitation method, sulfide precipitation method, solvent extraction method and ion exchange resin method. Solvent extraction has been used in purification processes of copper refinery, uranium refinery, platinum metal refinery and rare earth metal refinery. Fundamental process of solvent extraction, a kind of commercial extractants, a way of determining a suitable extractant and an equipment are discussed. Finally, it will be emphasized how the separation of rare earths is improved in solvent extraction. (author) 21 figs., 8 tabs., 8 refs

Effects of prey macronutrient content on body composition and nutrient intake in a web-building spider.

Directory of Open Access Journals (Sweden)

Jesse Hawley

Full Text Available The nutritional composition of diets can vary widely in nature and have large effects on the growth, reproduction and survival of animals. Many animals, especially herbivores, will tightly regulate the nutritional composition of their body, which has been referred to as nutritional homeostasis. We tested how experimental manipulation of the lipid and protein content of live prey affected the nutrient reserves and subsequent diet regulation of web-building spiders, Argiope keyserlingi. Live locusts were injected with experimental solutions containing specific amounts of lipid and protein and then fed to spiders. The nutrient composition of the spiders' bodies was directly related to the nutrient composition of the prey on which they fed. We then conducted an experiment where spiders were fed either high lipid or high protein prey and subsequently provided with two large unmanipulated locusts. Prior diet did not affect the amount or ratio of lipid and protein ingested by spiders when feeding on unmanipulated prey. Argiope keyserlingi were flexible in the storage of lipid and protein in their bodies and did not bias their extraction of nutrients from prey to compensate for previously biased diets. Some carnivores, especially those that experience frequent food limitation, may be less likely to strictly regulate their body composition than herbivores because food limitation may encourage opportunistic ingestion and assimilation of nutrients.

Drilling solutions developed on organo-silicon compounds

Energy Technology Data Exchange (ETDEWEB)

Belov, V P

1981-01-01

Confirms the positive effect of polymers on various clay solutions, including heavy barite, over a wide range of temperatures. Depending on the mineralogical composition of the solid phase of the solution and its level of mineralization, these substances may be used as reagent-stabilizers or viscosity reducers and, in certain instances, as combined-action reagents.

Influence of clay particles on microfluidic-based preparation of hydrogel composite microsphere

Science.gov (United States)

Hong, Joung Sook

2016-05-01

For the successful fabrication of a hydrogel composite microsphere, this study aimed to investigate the influence of clay particles on microsphere formation in a microfluidic device which has flow focusing and a 4.5:1 contraction channel. A poly alginic acid solution (2.0 wt.%) with clay particles was used as the dispersed phase to generate drops in an oil medium, which then merged with drops of a CaCl2 solution for gelation. Drop generations were observed with different flow rates and particles types. When the flow rate increased, drop generation was enhanced and drop size decreased by the build-up of more favorable hydrodynamic flow conditions to detach the droplets. The addition of a small amount of particles insignificantly changed the drop generation behavior even though it reduced interfacial tension and increased the viscosity of the solution. Instead, clays particles significantly affected hydro-gelation depending on the hydrophobicity of particles, which produced further heterogeneity in the shape and size of microsphere.

Puncture-Healing Thermoplastic Resin Carbon-Fiber-Reinforced Composites

Science.gov (United States)

Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

2015-01-01

A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

Joint analysis of quantitative trait loci and major-effect causative mutations affecting meat quality and carcass composition traits in pigs.

Science.gov (United States)

Cherel, Pierre; Pires, José; Glénisson, Jérôme; Milan, Denis; Iannuccelli, Nathalie; Hérault, Frédéric; Damon, Marie; Le Roy, Pascale

2011-08-29

Detection of quantitative trait loci (QTLs) affecting meat quality traits in pigs is crucial for the design of efficient marker-assisted selection programs and to initiate efforts toward the identification of underlying polymorphisms. The RYR1 and PRKAG3 causative mutations, originally identified from major effects on meat characteristics, can be used both as controls for an overall QTL detection strategy for diversely affected traits and as a scale for detected QTL effects. We report on a microsatellite-based QTL detection scan including all autosomes for pig meat quality and carcass composition traits in an F2 population of 1,000 females and barrows resulting from an intercross between a Pietrain and a Large White-Hampshire-Duroc synthetic sire line. Our QTL detection design allowed side-by-side comparison of the RYR1 and PRKAG3 mutation effects seen as QTLs when segregating at low frequencies (0.03-0.08), with independent QTL effects detected from most of the same population, excluding any carrier of these mutations. Large QTL effects were detected in the absence of the RYR1 and PRKGA3 mutations, accounting for 12.7% of phenotypic variation in loin colour redness CIE-a* on SSC6 and 15% of phenotypic variation in glycolytic potential on SSC1. We detected 8 significant QTLs with effects on meat quality traits and 20 significant QTLs for carcass composition and growth traits under these conditions. In control analyses including mutation carriers, RYR1 and PRKAG3 mutations were detected as QTLs, from highly significant to suggestive, and explained 53% to 5% of the phenotypic variance according to the trait. Our results suggest that part of muscle development and backfat thickness effects commonly attributed to the RYR1 mutation may be a consequence of linkage with independent QTLs affecting those traits. The proportion of variation explained by the most significant QTLs detected in this work is close to the influence of major-effect mutations on the least affected

Joint analysis of quantitative trait loci and major-effect causative mutations affecting meat quality and carcass composition traits in pigs

Directory of Open Access Journals (Sweden)

Iannuccelli Nathalie

2011-08-01

Full Text Available Abstract Background Detection of quantitative trait loci (QTLs affecting meat quality traits in pigs is crucial for the design of efficient marker-assisted selection programs and to initiate efforts toward the identification of underlying polymorphisms. The RYR1 and PRKAG3 causative mutations, originally identified from major effects on meat characteristics, can be used both as controls for an overall QTL detection strategy for diversely affected traits and as a scale for detected QTL effects. We report on a microsatellite-based QTL detection scan including all autosomes for pig meat quality and carcass composition traits in an F2 population of 1,000 females and barrows resulting from an intercross between a Pietrain and a Large White-Hampshire-Duroc synthetic sire line. Our QTL detection design allowed side-by-side comparison of the RYR1 and PRKAG3 mutation effects seen as QTLs when segregating at low frequencies (0.03-0.08, with independent QTL effects detected from most of the same population, excluding any carrier of these mutations. Results Large QTL effects were detected in the absence of the RYR1 and PRKGA3 mutations, accounting for 12.7% of phenotypic variation in loin colour redness CIE-a* on SSC6 and 15% of phenotypic variation in glycolytic potential on SSC1. We detected 8 significant QTLs with effects on meat quality traits and 20 significant QTLs for carcass composition and growth traits under these conditions. In control analyses including mutation carriers, RYR1 and PRKAG3 mutations were detected as QTLs, from highly significant to suggestive, and explained 53% to 5% of the phenotypic variance according to the trait. Conclusions Our results suggest that part of muscle development and backfat thickness effects commonly attributed to the RYR1 mutation may be a consequence of linkage with independent QTLs affecting those traits. The proportion of variation explained by the most significant QTLs detected in this work is close to the

Functional and compositional responses in soil microbial communities along two metal pollution gradients: does the level of historical pollution affect resistance against secondary stress?

NARCIS (Netherlands)

Azarbad, H.; Niklinska, M.; Nikiel, K.; van Straalen, N.M.; Röling, W.F.M.

2015-01-01

We examined how the exposure to secondary stressors affected the functional and compositional responses of microbial communities along two metal pollution gradients in Polish forests and whether responses were influenced by the level of metal pollution. Basal respiration rate and community

Effect of layering sequence and chemical treatment on the mechanical properties of woven kenaf–aramid hybrid laminated composites

International Nuclear Information System (INIS)

Yahaya, R.; Sapuan, S.M.; Jawaid, M.; Leman, Z.; Zainudin, E.S.

2015-01-01

Highlights: • The mechanical properties of woven kenaf/Kevlar hybrid composites were analysed. • The layering sequences affect the mechanical properties of hybrid composites. • Treated kenaf improves the mechanical properties of hybrid composites. - Abstract: This work aims to evaluate the effect of layering sequence and chemical treatment on mechanical properties of woven kenaf–Kevlar composites. Woven kenaf–aramid hybrid laminated composites fabricated through hand lay-up techniques by arranging woven kenaf and Kevlar fabrics in different layering sequences and by using treated kenaf mat. To evaluate the effect of chemical treatment on hybrid composites, the woven kenaf mat was treated with 6% sodium hydroxide (NaOH) diluted solution and compared mechanical properties with untreated kenaf hybrid composites. Results shows that the tensile properties of hybrid composites improved in 3-layer composites compared to 4-layer composites. Hybrid composite with Kevlar as outer layers display a better mechanical properties as compared to other hybrid composites. Tensile and flexural properties of treated hybrid composites are better than non-treated hybrid composites. The fractured surface of hybrid composites was investigated by scanning electron microscopy. This study is a part of exploration of potential application of the hybrid composite in high velocity impact application

Development of standardized radioactive 46Sc solution

International Nuclear Information System (INIS)

Du Hongshan; Jia Zhang; Yu Yiguang; Sun Naiyao

1988-01-01

A method of preparation of standardized radioactive 46 Sc solution is developed. The separation of 46 Sc, the composition of 46 Sc solution and its stability, and radioactivity measurement of 46 Sc are systematically studied. The results obtained in the study and in the applications in many laboratories have shown that our method is effective and reliable

The growth and tensile deformation behavior of the silver solid solution phase with zinc

International Nuclear Information System (INIS)

Wu, Jiaqi; Lee, Chin C.

2016-01-01

The growth of homogeneous silver solid solution phase with zinc are conducted at two different compositions. X-ray diffraction (XRD) and Scanning electron microscope/Energy dispersive X-ray spectroscopy (SEM/EDX) are carried out for phase identification and chemical composition verification. The mechanical properties of silver solid solution phase with zinc are evaluated by tensile test. The engineering and true stress vs. strain curves are presented and analyzed, with those of pure silver in comparison. According to the experimental results, silver solid solution phase with zinc at both compositions show tempered yield strength, high tensile strength and large uniform strain compared to those of pure silver. Fractography further confirmed the superior ductility of silver solid solution phase with zinc at both compositions. Our preliminary but encouraging results may pave the way for the silver based alloys to be applied in industries such as electronic packaging and structure engineering.

Interaction of Brilliant Blue dye solution with soil and its effect on mobility of compounds around the zones of preferenial flows at spruce stand

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Bebej Juraj

2017-06-01

Full Text Available We performed field experiment with 10 g l−1 concentration of Brilliant Blue solutes in 100 l of water sprinkling on 1 × 1 m surface of the Dystric Cambisol. Consequently, four vertical profiles were exposed at experimental plot after 2 hours (CUT 2, 24 hours (CUT 24, 27 hours (CUT 27 and after 504 hours (CUT 504 in order to analyse spatiotemporal interactions among the BB solution (Na-salts, soil exchangeable complex and fine earth soil (% samples extracted from both the high and low coloured zones located around the optically visualised macropore preferred flow (PF zones. The concentration changes were quantifying via soil profiles not affected by BB (termed as REF located in the close vicinity of experimental plot. Observed changes in pH (H2O, chemical composition of fineearth soil, as well as in concentration of Na+ in soil exchangeable complex to suggest, the BB dye solution didn’t represent an inert tracer, but compounds strongly involved in reaction with surrounding soils. Recorded chemical trends seems to be the result both the competitive processes between the Na+ of BB dye solution and composition of surrounding soil exchangeable complex, as well and the spatial-temporal controlled mechanism of dye solution transfer in soil.

Characterization and Antimicrobial Properties of Gamma Irradiated Starch/ Chitosan/ Ag Nano composites

International Nuclear Information System (INIS)

Khalil, S.A.; Hassan, M.S.; Ali, N.M.

2016-01-01

Composites based on different ratios of starch and chitosan, in the presence of a constant amount of silver nanoparticles (AgNPs), were prepared in the form of thin films by casting solutions. The gamma irradiated composites were characterized in terms of solution viscosity, FTIR, XRD, TGA and SEM. In addition, the antimicrobial activity of the prepared composites against different microorganisms was investigated. The results showed that the increase of irradiation dose more than 5 kGy leads to a decrease in the composite solution viscosity, the overall crystallinity, thermal stability and antimicrobial activity of the prepared films. The prepared starch based composites were applied to cotton samples to demonstrate the antimicrobial finishing. Acceptable antimicrobial results against both the tested pathogenic bacteria and in burial test were obtained.

Parameters affecting level measurement interpretation of nuclear fuel solutions

International Nuclear Information System (INIS)

Hunt, B.A.; Landat, D.A.

1999-01-01

This paper describes a level measurement technique commonly used in the measurement of radioactive liquids and equipment utilised by the inspectors for safeguards purposes. Some of the influencing parameters affecting the measurement results by this technique are characterised. An essential requisite for successful process operations in chemical facilities involving liquids generally require some physical measurements to be made in-line for both process and quality control in order to achieve the necessary final product specifications . In nuclear fuel reprocessing facilities, the same objectives apply coupled however with an additional requirement of achieving nuclear material accountancy and control. In view of the strategic importance of some of the process vessels in nuclear facilities, accountancy has to be supported by volume and density measurements of low uncertainty. Inspectors therefore require instruments which are at the very least as good as or better than operator's equipment. The classical measurement technique and most widely applied for process liquids in nuclear installations is the bubbler probe or dip-tube technique. Here a regulated flow of air passes through tubes inserted to various depths into the vessel and pressure readings are measured which are a function of the presence of liquid height and density of solution in the tank. These readings, taken together with a pre-determined calibration curve are sufficient for the volume and amount of liquor in a tank to be quantified. All measurement equipment and instrumentation are long distances from the tank environment. The key physical parameter to measure at this location is therefore pressure. Equipment designed developed, commissioned and tested in the tank measurement facilities at Ispra and in nuclear installations in Europe, Japan and the USA, house digital pressure transducer modules with manufacture's declared features of better than 0.01% accuracy and long term stability of 0.01% full

Non-monotonic compositional dependence of isothermal bulk modulus of the (Mg1–xMnxCr2O4 spinel solid solutions, and its origin and implication

Directory of Open Access Journals (Sweden)

Xi Liu

2016-12-01

Full Text Available The compressibility of the spinel solid solutions, (Mg1−xMnxCr2O4 with x = 0.00 (0, 0.20 (0, 0.44 (2, 0.61 (2, 0.77 (2 and 1.00 (0, has been investigated by using a diamond-anvil cell coupled with synchrotron X-ray radiation up to ∼10 GPa (ambient T. The second-order Birch–Murnaghan equation of state was used to fit the PV data, yielding the following values for the isothermal bulk moduli (KT, 198.2 (36, 187.8 (87, 176.1 (32, 168.7 (52, 192.9 (61 and 199.2 (61 GPa, for the spinel solid solutions with x = 0.00 (0, 0.20 (0, 0.44 (2, 0.61 (2, 0.77 (2 and 1.00 (0, respectively (KT′ fixed as 4. The KT value of the MgCr2O4 spinel is in good agreement with existing experimental determinations and theoretical calculations. The correlation between the KT and x is not monotonic, with the KT values similar at both ends of the binary MgCr2O4MnCr2O4, but decreasing towards the middle. This non-monotonic correlation can be described by two equations, KT = −49.2 (11x + 198.0 (4 (x ≤ ∼0.6 and KT = 92 (41x + 115 (30 (x ≥ ∼0.6, and can be explained by the evolution of the average bond lengths of the tetrahedra and octahedra of the spinel solid solutions. Additionally, the relationship between the thermal expansion coefficient and composition is correspondingly reinterpreted, the continuous deformation of the oxygen array is demonstrated, and the evolution of the component polyhedra is discussed for this series of spinel solid solutions. Our results suggest that the correlation between the KT and composition of a solid solution series may be complicated, and great care should be paid while estimating the KT of some intermediate compositions from the KT of the end-members.

PREPARATION AND CHARACTERIZATION OF COMPOSITES COMPRISING MODIFIED HARDWOOD AND WOOD POLYMERS/POLY(VINYL CHLORIDE

Directory of Open Access Journals (Sweden)

Ruxanda Bodîrlău

Full Text Available Chemical modification of hardwood sawdust from ash-tree species was carried out with a solution of maleic anhydride in acetone. Wood polymers, lignin, and cellulose were isolated from the wood sawdust and modified by the same method. Samples were characterized by Fourier transform infrared spectroscopy (FTIR, providing evidence that maleic anhydride esterifies the free hydroxyl groups of the wood polymer components. Composites comprising chemically modified wood sawdust and wood polymers (cellulose, lignin-as variable weight percentages-, and poly (vinyl chloride were obtained and further characterized by using FTIR spectroscopy and scanning electron microscopy (SEM. The thermal behavior of composites was investigated by using the thermogravimetric analysis (TGA. In all cases, thermal properties were affected by fillers addition.

Nectar sugar composition of European Caryophylloideae (Caryophyllaceae) in relation to flower length, pollination biology and phylogeny.

Science.gov (United States)

Witt, T; Jürgens, A; Gottsberger, G

2013-10-01

Floral nectar composition has been explained as an adaptation to factors that are either directly or indirectly related to pollinator attraction. However, it is often unclear whether the sugar composition is a direct adaptation to pollinator preferences. Firstly, the lower osmolality of sucrose solutions means that they evaporate more rapidly than hexose solutions, which might be one reason why sucrose-rich nectar is typically found in flowers with long tubes (adapted to long-tongued pollinators), where it is better protected from evaporation than in open or short-tubed flowers. Secondly, it can be assumed that temperature-dependent evaporation is generally lower during the night than during the day so that selection pressure to secrete nectar with high osmolality (i.e. hexose-rich solutions) is relaxed for night-active flowers pollinated at night. Thirdly, the breeding system may affect selection pressure on nectar traits; that is, for pollinator-independent, self-pollinated plants, a lower selective pressure on nectar traits can be assumed, leading to a higher variability of nectar sugar composition independent of pollinator preferences, nectar accessibility and nectar protection. To analyse the relations between flower tube length, day vs. night pollination and self-pollination, the nectar sugar composition was investigated in 78 European Caryophylloideae (Caryophyllaceae) with different pollination modes (diurnal, nocturnal, self-pollination) using high-performance liquid chromatography (HPLC). All Caryophylleae species (Dianthus and relatives) were found to have nectar with more than 50% sucrose, whereas the sugar composition of Sileneae species (Silene and relatives) ranged from 0% to 98.2%. In the genus Silene, a clear dichotomous distribution of sucrose- and hexose-dominant nectars is evident. We found a positive correlation between the flower tube length and sucrose content in Caryophylloideae, particularly in day-flowering species, using both conventional

Study of interaction of bismuth, strontium, calcium copper, lead nitrates solutions with sodium oxalate solution with the aim of HTSC synthesis

International Nuclear Information System (INIS)

Danilov, V.P.; Krasnobaeva, O.N.; Nosova, T.A.

1993-01-01

With the aim of developing a new technique for HTSC oxides synthesis on the base of combined sedimentation of hydroxy salts and their heat treatment is studied interaction of bismuth, strontium, calcium, copper and lead nitrates with alkali solution of sodium oxalate. Conditions for total sedimentation of all five metals from the solution are found. The phase composition of interaction products is determined. It is established that they are high-dispersed homogeneous mixture of three phases of variable composition: twin hydroxalate of copper-bismuth, lead hydroxalate and twin oxalate of strontium-calcium. After heat treatment of the phases are obtained the HTSC oxides

Preparation and characterization of PVC /ENR/CNTs Nano composites

International Nuclear Information System (INIS)

Ratnam, C.T.; Nur Azrini Ramlee; Keong, C.C.

2011-01-01

Poly (vinyl chloride), PVC/ epoxidized natural rubber blend, ENR/ carbon nano tubes, CNTs were prepared by using melt and solution blending methods. Addition of 2 phr of CNTs found to cause a drop in the tensile strength, Ts of the 50/ 50 PVC/ ENR blend. The nano composites prepared by the melt blending method exhibited higher values of Ts compared to the nano composites prepared by solution blending. Melt blending found to be an efficient method to prepare PVC/ ENR/ CNTs nano composites. (author)

SOILSOLN: A Program for Teaching Equilibria Modeling of Soil Solution Composition.

Science.gov (United States)

Wolt, Jeffrey D.

1989-01-01

Presents a computer program for use in teaching ion speciation in soil solutions. Provides information on the structure of the program, execution, and software specifications. The program estimates concentrations of ion pairs, hydrolytic species, metal-organic complexes, and free ions in solutions. (Author/RT)

Analysis on porous aluminum anodic oxide film formed in Re-OA-H{sub 3}PO{sub 4} solution

Energy Technology Data Exchange (ETDEWEB)

Wang, H. [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China); Wang, H.W. [State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)]. E-mail: hwwang@sjtu.edu.cn

2006-06-10

An anodic porous film on aluminum was prepared in a mixed electrolyte of phosphoric acid and organic acid and cerium salt. The growth, morphology and chemical composition of the film were investigated. The results indicate that the growth of porous layers in this solution undergo three stages during anodizing, as in other conventional solution, while the whole growth rate is nonlinear. This electrolyte is sensitive to anodizing temperature, which affects current density in great degree. SEM indicates the surface morphology of film is strongly dependent on temperature and current density and its cross-section has two distinct oxide layers. Al, O and P are found in the film with different distribution in the two layers with EPMA. However, Ce has been detected on the outer surface with EDAX. XPS analysis on the electron binding energy of the component elements show the chemical composition of oxide film surface are Al{sub 2}O{sub 3}, Ce(OH) and some phosphates. The formation mechanics of Ce compound is also deduced.

Environmental Factors Affecting the Strength Characteristics of Modified Resin Mortars

Science.gov (United States)

Debska, Bernardeta; Licholai, Lech

2017-12-01

Resin concretes are composites in which a cement binder has been completely replaced by a synthetic resin. These materials are a good choice for the construction industry, especially in solutions requiring high strength, fast curing and durability. Polymer mortars are mainly used for the manufacture of industrial floors and prefabricated products such as tanks for aggressive chemicals, sewage pipes, or road and bridge drainage systems, as well as for the repair of damaged concrete structures. In all these applications, the strength and high chemical resistance of the applied material solutions are of key importance. It is particularly crucial to obtain information on how resin composites behave when exposed to aggressive agents over extended periods of time. It is also very important to use waste materials in order to obtain resin composites, as these activities are very well inscribed in the idea of environmental protection and meet the criteria of sustainable construction. The mortars described in this article meet the above principles. The article presents how the compressive strength of glycolyzate-modified epoxy mortars, obtained with the use of poly(ethylene terephthalate), changes after they are immersed in 10% sodium chloride solution. Sodium chloride solution was chosen due to the prospective applicability of the tested composites as repair materials used for e.g. bridges or overpasses that are exposed to this salt solution in wintertime. Changes in the properties of the composite samples were monitored over the period of one year. Statistical analysis of the test results was carried out with the use of Statistica programme. The module available in the mentioned program called Nonparametric Statistics - Comparing multiple independent samples made it possible to check the monitoring times during which the compressive strength values differed significantly. The obtained results allowed for determining the equation of the function approximating the course of

Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

Science.gov (United States)

Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

2015-01-01

“Clumped-isotope” thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope “clumps”). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals.We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect.Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3− and CO32−. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many

Beyond temperature: Clumped isotope signatures in dissolved inorganic carbon species and the influence of solution chemistry on carbonate mineral composition

Science.gov (United States)

Tripati, Aradhna K.; Hill, Pamela S.; Eagle, Robert A.; Mosenfelder, Jed L.; Tang, Jianwu; Schauble, Edwin A.; Eiler, John M.; Zeebe, Richard E.; Uchikawa, Joji; Coplen, Tyler B.; Ries, Justin B.; Henry, Drew

2015-10-01

;Clumped-isotope; thermometry is an emerging tool to probe the temperature history of surface and subsurface environments based on measurements of the proportion of 13C and 18O isotopes bound to each other within carbonate minerals in 13C18O16O22- groups (heavy isotope ;clumps;). Although most clumped isotope geothermometry implicitly presumes carbonate crystals have attained lattice equilibrium (i.e., thermodynamic equilibrium for a mineral, which is independent of solution chemistry), several factors other than temperature, including dissolved inorganic carbon (DIC) speciation may influence mineral isotopic signatures. Therefore we used a combination of approaches to understand the potential influence of different variables on the clumped isotope (and oxygen isotope) composition of minerals. We conducted witherite precipitation experiments at a single temperature and at varied pH to empirically determine 13C-18O bond ordering (Δ47) and δ18O of CO32- and HCO3- molecules at a 25 °C equilibrium. Ab initio cluster models based on density functional theory were used to predict equilibrium 13C-18O bond abundances and δ18O of different DIC species and minerals as a function of temperature. Experiments and theory indicate Δ47 and δ18O compositions of CO32- and HCO3- ions are significantly different from each other. Experiments constrain the Δ47-δ18O slope for a pH effect (0.011 ± 0.001; 12 ⩾ pH ⩾ 7). Rapidly-growing temperate corals exhibit disequilibrium mineral isotopic signatures with a Δ47-δ18O slope of 0.011 ± 0.003, consistent with a pH effect. Our theoretical calculations for carbonate minerals indicate equilibrium lattice calcite values for Δ47 and δ18O are intermediate between HCO3- and CO32-. We analyzed synthetic calcites grown at temperatures ranging from 0.5 to 50 °C with and without the enzyme carbonic anhydrase present. This enzyme catalyzes oxygen isotopic exchange between DIC species and is present in many natural systems. The two

Multi-material Preforming of Structural Composites

Energy Technology Data Exchange (ETDEWEB)

Norris, Robert E. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eberle, Cliff C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pastore, Christopher M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sudbury, Thomas Z. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Xiong, Fue [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hartman, David [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-05-01

Fiber-reinforced composites offer significant weight reduction potential, with glass fiber composites already widely adopted. Carbon fiber composites deliver the greatest performance benefits, but their high cost has inhibited widespread adoption. This project demonstrates that hybrid carbon-glass solutions can realize most of the benefits of carbon fiber composites at much lower cost. ORNL and Owens Corning Reinforcements along with program participants at the ORISE collaborated to demonstrate methods for produce hybrid composites along with techniques to predict performance and economic tradeoffs. These predictions were then verified in testing coupons and more complex demonstration articles.

Studies on the effect of Pu and fission products on extraction selectivity of polymeric composite of ammonium phosphomolybdate towards 137Cs from nitric acid solutions

International Nuclear Information System (INIS)

Tripathi, S.C.; Pathak, S.K.; Jambunathan, U.; Dakshinamoorthy, A.; Kumar, Manmohan; Bajaj, P.N.

2007-01-01

Ultrafine particle size of ammonium phosphomolybdate (AMP) though selective sorbent for Cs form acidic solution, has limitation due to its incompatibility with column operation under practical conditions. A polymeric composite containing ammonium Phospho molybdate(AMP) developed indigenously in granular form, has shown encouraging results for Cs uptake from acidic solutions. Present investigation describes experimental observations carried out to find out the effect of presence of Pu and fission products on the 137 Cs uptake. The polymeric material shown some tendency for sorption of Pu which is found to decrease with increasing acidity. It has great selectivity with respect to other fission products like cerium, zirconium, and ruthenium. (author)

Robust and efficient solution procedures for association models

DEFF Research Database (Denmark)

Michelsen, Michael Locht

2006-01-01

Equations of state that incorporate the Wertheim association expression are more difficult to apply than conventional pressure explicit equations, because the association term is implicit and requires solution for an internal set of composition variables. In this work, we analyze the convergence...... behavior of different solution methods and demonstrate how a simple and efficient, yet globally convergent, procedure for the solution of the equation of state can be formulated....

Training affects muscle phospholipid fatty acid composition in humans

DEFF Research Database (Denmark)

Helge, Jørn Wulff; Wu, B J; Willer, Mette

2001-01-01

on the muscle membrane phospholipid fatty acid composition in humans. Seven male subjects performed endurance training of the knee extensors of one leg for 4 wk. The other leg served as a control. Before, after 4 days, and after 4 wk, muscle biopsies were obtained from the vastus lateralis. After 4 wk......, the phospholipid fatty acid contents of oleic acid 18:1(n-9) and docosahexaenoic acid 22:6(n-3) were significantly higher in the trained (10.9 +/- 0.5% and 3.2 +/- 0.4% of total fatty acids, respectively) than the untrained leg (8.8 +/- 0.5% and 2.6 +/- 0.4%, P fatty acids...... was significantly lower in the trained (11.1 +/- 0.9) than the untrained leg (13.1 +/- 1.2, P fatty acid composition. Citrate synthase activity was increased by 17% in the trained compared with the untrained leg (P

Doped-carbon composites, synthesizing methods and applications of the same

Science.gov (United States)

Viswanathan, Tito

2017-05-09

A method of synthesizing a doped carbon composite includes preparing a solution having a carbon source material and a heteroatom containing additive, evaporating the solution to yield a plurality of powders, and subjecting the plurality of powders to a heat treatment for a duration of time effective to produce the doped carbon composite.

Molecular interactions in gelatin/chitosan composite films.

Science.gov (United States)

Qiao, Congde; Ma, Xianguang; Zhang, Jianlong; Yao, Jinshui

2017-11-15

Gelatin and chitosan were mixed at different mass ratios in solution forms, and the rheological properties of these film-forming solutions, upon cooling, were studied. The results indicate that the significant interactions between gelatin and chitosan promote the formation of multiple complexes, reflected by an increase in the storage modulus of gelatin solution. Furthermore, these molecular interactions hinder the formation of gelatin networks, consequently decreasing the storage modulus of polymer gels. Both hydrogen bonds and electrostatic interactions are formed between gelatin and chitosan, as evidenced by the shift of the amide-II bands of polymers. X-ray patterns of composite films indicate that the contents of triple helices decrease with increasing chitosan content. Only one glass transition temperature (T g ) was observed in composite films with different composition ratios, and it decreases gradually with an increase in chitosan proportion, indicating that gelatin and chitosan have good miscibility and form a wide range of blends. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anodic behavior of stainless-steel substrate in organic electrolyte solutions containing different lithium salts

International Nuclear Information System (INIS)

Furukawa, Kazuki; Yoshimoto, Nobuko; Egashira, Minato; Morita, Masayuki

2014-01-01

Highlights: • We investigated anodic behavior of stainless-steel in organic electrolytes for advanced capacitor. • Anion of the electrolyte affected the anodic stability of the alloy. • Anodic passivation occurs in LiPF 6 solution but pitting or active dissolution proceeds in other electrolyte solutions. • Fluoride source in the solution contributes to forming a stable surface layer on the stainless steel. - Abstract: The anodic behavior of austenitic stainless-steel, SUS304, as a current collector of positive electrode in lithium-ion battery/capacitor has been investigated in organic electrolyte solutions based on a mixed alkyl carbonate solvent with different lithium salts. Stable passivation characteristics were observed for the stainless-steel in the LiPF 6 solution, but pitting corrosion or active dissolution proceeded in the solutions containing other anions, BF 4 - , (CF 3 SO 2 ) 2 N - (TFSA - ) and ClO 4 - . The mass ratios of the dissolved metal species in the solutions of LiTFSA and LiClO 4 were equivalent to that of the alloy composition, which suggests that no preferential dissolution occurs during the anodic polarization in these electrolyte solutions. An HF component formed by decomposition of PF 6 - with the contaminate water will act as an F - source for the formation of a surface fluoride layer, that will contribute to the anodic stability of SUS304 in the LiPF 6 solution. The anodic corrosion in the LiTFSA solution was suppressed in part by mixing the PF 6 salt or adding HF in the electrolyte

Thermodynamic characteristics of systems with solid solutions composed of crystal hydrates of lanthanide and yttrium chlorides, at 250C. III. Systems of Roozeboom's type IV, with restricted solid solutions

International Nuclear Information System (INIS)

Sokolova, N.P.

1983-01-01

The values of the activity, the activity coefficients, the free energy of mixing and the excess free energy of mixing have been calculated for CeCl 3 -LnCl 3 -H 2 O systems (where Ln identical with Sm, Gd, Dy, Ho, Er, Y) containing solid solutions of types IV and IVa. It is shown that the stability of the solid solutions decreases with increasing difference between the radii of the cations of cerium and the second lanthanide, which enter into the composition of the components of the solid solutions. The factors determining the composition of a liquid solution corresponding to the eutonic point are specified

Effects of sterilizing radiation dose on the amino acid composition of normal human Ig(G)

International Nuclear Information System (INIS)

Kaupert, N.L.; Mariano, E.E.

1981-01-01

In order to verify gamma radiation effect of 60 Co, samples of Normal human Ig(G) in a) pH 7 solutions with different concentrations, and b) in liophilized state, were irradiated. In both, the quali and quantitative amino acid compositions have been studied. No changes in amino acid composition were observed, for doses up to 10 Mrad delivered to the liophilized samples. Nevertheless, when 5 mg/ml and 10 mg/ml solutions of Ig(G) were irradiated with a 2 Mrad gamma dose, both were affected. The damage appeared in greater proportion in the samples with lower concentration. Cistine was the amino acid most damaged and the loss of methionine, proline histidine, arginine, tirosine and phenilalanine, decreased in this order. The analysis of the experimental data shows that liophilized human Ig(G) can be treated with doses higher than those required to achieve sterilization, without modifying its immunologic and primary proteic structure properties. Therefore, gamma sterilization feasibility has been proved for normal human Ig(G) only in the liophilized state. (author) [es

Study on the improvement of toughness of Nb-based super high temperature materials by forming solid solution and composites; Niobuki chokoon zairyo no koyoka to fukugoka ni yoru kyojinsei kaizen ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-03-01

If materials superior to Ni-based and Co-based super alloys could be developed, great progress is expected in the energy source saving, enhancement of aircraft speed, and simplification of member structure. Metals having high fusing point are prospective as well as C/C composites and ceramics among possible materials. Especially, Nb has a similar density to Ni, and its fusing point is 1,000 centigrade higher than Ni. It has also ductility. Furthermore, it is characterized by the formation of solid solution with other various metals having high fusing point. Accordingly, Nb-based composite alloys having excellent high temperature strength as well as excellent ductility and toughness can be developed by enhancing the solid solution formation and the dispersion with composites of compound phases using Nb as a base material. The purpose of this study is to provide fundamental data for the development of Nb-based composite alloys. The optimum matrix materials and their fabrication processes have been investigated, to evaluate their high temperature properties. Consequently, it was found that the enhancement by the deposition of intermetallic compounds or by the dispersion of oxides was an effective method for the formation of composites of Nb-based alloys. 4 refs., 88 figs., 24 tabs.

Composite materials design and applications

CERN Document Server

Gay, Daniel; Tsai, Stephen W

2002-01-01

PART ONE. PRINCIPLES OF CONSTRUCTIONCOMPOSITE MATERIALS, INTEREST AND PROPERTIESWhat is Composite Material Fibers and MatrixWhat can be Made Using Composite Materials?Typical Examples of Interest on the Use of Composite MaterialsExamples on Replacing Conventional Solutions with CompositesPrincipal Physical PropertiesFABRICATION PROCESSESMolding ProcessesOther Forming ProcessesPractical Hints in the Manufacturing ProcessesPLY PROPERTIESIsotropy and AnisotropyCharacteristics of the Reinforcement-Matrix MixtureUnidirectional PlyWoven FabricsMats and Reinforced MatricesMultidimensional FabricsMetal Matrix CompositesTestsSANDWICH STRUCTURES:What is a Sandwich Structure?Simplified FlexureA Few Special AspectsFabrication and Design ProblemsNondestructive Quality ControlCONCEPTION AND DESIGNDesign of a Composite PieceThe LaminateFailure of LaminatesSizing of LaminatesJOINING AND ASSEMBLYRiveting and BoltingBondingInsertsCOMPOSITE MATERIALS AND AEROSPACE CONSTRUCTIONAircraftHelicoptersPropeller Blades for AirplanesTur...

Production and characterization of composites based on ramie cellulose micro fibers filler

International Nuclear Information System (INIS)

Edi Syafri; Anwar Kasim and Alfi Asben; Hairul Abral; Sudirman

2018-01-01

This research studied production and characterization of bioplastic composites by using cellulose fibers (Cellulose Micro Fibers/CMF) as reinforcement in tapioca starch. CMF ramie was produced by using milling method (CMFM) and ultrasonication (CMFU) with particle size 3,51 μm and 0,388 μm, respectively. The fabrication of the bioplastic composites was performed by solution casting with addition glycerol as a plasticizer. SEM, UTM, XRD, and DSC characterization were carried out. The results show that the size and concentration of CMF significantly affect the physical bioplastic composites. The SEM displays the good interaction CMF filler with the tapioca starch matrix, where the small sized hemophytic CMF bioplastic exhibits are more homogeneous compact and surface structure. The optimum value of tensile strength is found in the addition of 8 % (w/w)CMF ramie from ultrasonication and milling results increased from 1.64 MPa to 3.31 MPa and 2.71 MPa, respectively. The thermal properties have low significant effect with addition ramie CMF.X-ray Diffraction Analysis (XRD) showed that the crystallinity of bioplastic composites increased with the addition of ramie CMF from 8.65 % to 20.21 % for CMFM and 15.12 % for CMFU. (author)

Tensile behavior of humid aged advanced composites for helicopter external fuel tank development

Directory of Open Access Journals (Sweden)

Condruz Mihaela

2018-01-01

Full Text Available Influence of humid aging on tensile properties of two polymeric composites was studied. The purpose of the study was to evaluate the suitability of the materials for a naval helicopter external fuel tank. Due to the application, the humid environment was kerosene and saline solution to evaluate the sea water effect on the composite tensile strength. The composite samples were immersed in kerosene for 168 hours, respective 1752 hours and in saline solution for 168 hours. Tensile tests were performed after the immersion. The composite sample tensile tests showed that kerosene and saline solution had no influence on the elastic modulus of the materials, but it was observed a slight improvement of the tensile strength of the two polymeric composites.

Sorption of radiocesium by composites of variable composition

International Nuclear Information System (INIS)

Someda, H.H.; El-zahhar, A.A.; Shehata, M.K.K.; El-Naggar, H.A.

2000-01-01

Cellulose and different natural materials - supported hexacyanoferrate composites were prepared and characterized by IR and x-ray diffraction studies. The stability of the prepared composites towards concentrated mineral acids was studied. The capacity of such prepared composites towards the uptake of cesium was calculated and found to be 1.5-1.7 meq/g. The capacity of the natural materials - supported composites was found to be slightly higher than that of the cellulose supported one. Different parameters affecting the sorption process of the radioelement such as acid concentration, Ph variation, competing ions and carrier concentration were studied. The release of the cesium traces from the composite materials was studied under different HCl concentrations and it was found that there is no release of the absorbed cesium up to 2.5 M even for long contact time up to two weeks. The work is under developing and extension

In vitro degradation behavior of Fe–20Mn–1.2C alloy in three different pseudo-physiological solutions

International Nuclear Information System (INIS)

Mouzou, Essowè; Paternoster, Carlo; Tolouei, Ranna; Purnama, Agung; Chevallier, Pascale; Dubé, Dominique; Prima, Frédéric

2016-01-01

High manganese austenitic steels such as Fe–20Mn–1.2C alloys are among the most promising candidates for biodegradable stents applications due to their high strength, high ductility and their chemical composition. In the current work, 14 day static in-vitro tests were performed in controlled atmosphere to assess the degradation behavior in three common pseudo-physiological solutions, i.e. commercial Hanks' (CH), modified Hanks' (MH) and albumin-enriched Dulbecco's modified phosphate buffered saline (DPBS) solutions. The degraded samples surfaces as well as the degradation products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Degradation of material and degradation products are shown to be strongly dependent on the test medium due to the presence of different ionic species such as HCO_3"−, CO_3"2"−, Cl"−, Ca"2"+ or phosphate groups. In both MH and CH solutions, the increased content of HCO_3"− ions seems to promote MnCO_3 crystal growth on sample surfaces whereas the presence of albumin and high content of phosphate ions promotes the formation of an amorphous layer rich in phosphates, iron and manganese. - Highlights: • Fe–20Mn–1.2C degradation is strongly affected by the solution chemical composition. • Adherent MnCO_3 formation is promoted by the presence of carbonates/bicarbonates. • Phosphates promote the formation of an amorphous layer on the surface substrate.

Stability of the Stevia-Derived Sweetener Rebaudioside A in Solution as Affected by Ultraviolet Light Exposure.

Science.gov (United States)

Zhang, Jiewen; Bell, Leonard N

2017-04-01

Rebaudioside A is a natural noncaloric high-potency sweetener extracted from the leaves of Stevia rebaudiana. With rebaudioside A use increasing in foods, understanding the factors affecting its stability is necessary. This project evaluated the degradation rate constants of rebaudioside A in water, 0.1 M phosphate buffer, and 0.1 M citrate buffer at pH 3 and 7 as a function of ultraviolet (UV) light intensity (365 nm, 0 μW/cm 2 for dark conditions, 27 μW/cm 2 for low intensity, and 190 μW/cm 2 for high intensity) at 32.5 °C. Rebaudioside A stability was adversely affected by light exposure. The pseudo-1st-order degradation rate constants increased significantly (P < 0.05) with increasing light intensity in all solutions. Under dark conditions, rebaudioside A in phosphate buffers was more susceptible to breakdown than in water and citrate buffers at both pH levels. However, exposure to UV light resulted in rebaudioside A degradation occurring approximately 10 times faster in citrate than in phosphate buffers at both pH levels. The sensitivity of rebaudioside A to UV light was greater in citrate buffers than in water or phosphate buffers. The use of light-protective packaging for beverages containing rebaudioside A will improve its stability. © 2017 Institute of Food Technologists®.

Solute concentration affects bradykinin-mediated increases in renal prostaglandin E2

International Nuclear Information System (INIS)

Zenser, T.V.; Davis, E.S.; Rapp, N.S.; Davis, B.B.

1981-01-01

The effects of solute concentration on the bradykinin-mediated increase in inner medullary slice prostaglandin E2 (PGE2) synthesis were investigated. PG content was determined by specific RIA. Bradykinin stimulation was prevented by the addition of the following solutes to Krebs buffer: 1.0 M urea, 0.5 or 1.0 M NaCl, 0.5 or 1.0 M mannitol, 1.0 M urea plus 0.5 M NaCl, or 1.0 M mannitol plus 0.5 M NaCl. By contrast, basal PGE2 synthesis was increased by 1.0 M mannitol or by 1.0 M mannitol plus 0.5 M NaCl, but decreased by 1.0 M urea. Urea elicited a concentration-dependent, reversible inhibition of bradykinin stimulation, with 0.01 M urea being the lowest effective concentration. By contrast, basal PGE2 synthesis was only reduced at a urea concentration greater than 0.6 M. Arachidonic acid-mediated increases in both PGE2 and PGF2 alpha synthesis were not prevented by 1.0 M urea. The latter suggests that neither PG endoperoxide synthetase nor PG endoperoxide E isomerase are inhibited by urea. The data indicate that different hypertonic solutions have different effects on basal PG production, but all inhibit bradykinin stimulation

Amorphous V-O-C composite nanofibers electrospun from solution precursors as binder- and conductive additive-free electrodes for supercapacitors with outstanding performance

Science.gov (United States)

Chen, Xia; Zhao, Bote; Cai, Yong; Tadé, Moses O.; Shao, Zongping

2013-11-01

Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well-dispersed in the carbon nanofibers, free from the formation of an aggregated crystalline phase, even in the case of V20. A specific surface area of 587.9 m2 g-1 was reached for V10 after calcination, which is approximately twice that of the vanadium-free carbon nanofibers (V0, 300.9 m2 g-1). To perform as an electrode for supercapacitors in an aqueous electrolyte, the V10 film delivered a specific capacitance of 463 F g-1 at 1 A g-1. V10 was also able to retain a specific capacitance of 380 F g-1, even at a current density of 10 A g-1. Additionally, very stable cycling stability was achieved, maintaining an outstanding specific capacitance of 400 F g-1 at 5 A g-1 after charge-discharge cycling 5000 times. Thus, V-O-C composite nanofibers are highly attractive electrode materials for flexible, high-power, thin film energy storage devices and applications.Flexible V-O-C composite nanofibers were fabricated from solution precursors via electrospinning and were investigated as free-standing and additive-free film electrodes for supercapacitors. Specifically, composite nanofibers (V0, V5, V10 and V20) with different vanadyl acetylacetonate (VO(acac)2) contents of 0, 5, 10 and 20 wt% with respect to polyacrylonitrile (PAN) were prepared. The composite nanofibers were comparatively studied using XRD, Raman spectroscopy, XPS, N2 adsorption-desorption, FE-SEM, TEM and S-TEM. The vanadium element was found to be well

Reinforced PEI/PVdF Multicore-Shell Structure Composite Membranes by Phase Prediction on a Ternary Solution

Directory of Open Access Journals (Sweden)

Jihye Chae

2018-04-01

Full Text Available To construct a polyetherimide (PEI-reinforced polyvinylidene fluoride (PVdF composite membrane with multicore-shell structure, a ternary solution was prepared and electrospun by single-nozzle electrospinning. A theoretical prediction was made for the feasibility of complete distinction of two phases. The diameters of the membrane fibers and the PEI multi-core fibrils varied with the PEI ratio and the spinning time, respectively. The tensile strength and modulus were improved to 48 MPa and 1.5 GPa, respectively. The shrinkage of the membrane was only 6.6% at 180 °C, at which temperature the commercial PE separator melted down. The reinforcement in mechanical and thermal properties is associated with multiple PEI nanofibrils oriented along the fiber axis. Indeed, the unique morphology of self-assembled multicore-shell fibers plays an important role in their properties. All in all, PEI/PVdF membranes are appropriate for a lithium-ion battery application due to their high mechanical strength, excellent thermal stability, and controllable textural properties.

Induced liquid-crystalline ordering in solutions of stiff and flexible amphiphilic macromolecules: Effect of mixture composition

International Nuclear Information System (INIS)

Glagolev, Mikhail K.; Vasilevskaya, Valentina V.; Khokhlov, Alexei R.

2016-01-01

Impact of mixture composition on self-organization in concentrated solutions of stiff helical and flexible macromolecules was studied by means of molecular dynamics simulation. The macromolecules were composed of identical amphiphilic monomer units but a fraction f of macromolecules had stiff helical backbones and the remaining chains were flexible. In poor solvents the compacted flexible macromolecules coexist with bundles or filament clusters from few intertwined stiff helical macromolecules. The increase of relative content f of helical macromolecules leads to increase of the length of helical clusters, to alignment of clusters with each other, and then to liquid-crystalline-like ordering along a single direction. The formation of filament clusters causes segregation of helical and flexible macromolecules and the alignment of the filaments induces effective liquid-like ordering of flexible macromolecules. A visual analysis and calculation of order parameter relaying the anisotropy of diffraction allow concluding that transition from disordered to liquid-crystalline state proceeds sharply at relatively low content of stiff components.

How do glycerol and dimethyl sulphoxide affect local tetrahedral structure of water around a nonpolar solute at low temperature? Importance of preferential interaction

Science.gov (United States)

Daschakraborty, Snehasis

2018-04-01

Glycerol and dimethyl sulphoxide (DMSO) have vital roles in cryoprotection of living cells, tissues, etc. The above action has been directly linked with disruption of hydrogen (H-) bond structure and dynamics of water by these cosolvents at bulk region and around various complex units, such as peptide, amino acid, protein, and lipid membrane. However, the disruption of the local structure of the water solvent around a purely hydrophobic solute is still not studied extensively. The latter is also important in the context of stabilization of protein from cold denaturation. Through all-atom molecular dynamics simulation, we have investigated the comparative effect of glycerol and DMSO on the orientational order of water around a nonpolar solute at -5 °C. A steady reduction of the tetrahedral order of water is observed at bulk (>10 Å distance from the solute) and solute interface (structure of the interfacial water more than that of the bulk water, glycerol affects the water structure almost uniformly at all regions around the solute. Furthermore, while glycerol helps to retain water molecules at the interface, DMSO significantly reduces the water content in that region. We have put forward a plausible mechanism for these contrasting roles of these cosolvents. The solute-cosolvent hydrophobic-interaction-induced orientational alignment of an interfacial cosolvent molecule determines whether the involvement of the cosolvent molecules in H-bonding with solvent water in the interface is akin to the bulk region or not.

Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide

Energy Technology Data Exchange (ETDEWEB)

Buckholtz, Gavin A.; Reger, Nina A. [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); Anderton, William D.; Schimoler, Patrick J. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Roudebush, Shana L.; Meng, Wilson S. [Division of Pharmaceutical Sciences, Duquesne University, Pittsburgh, PA 15282 (United States); Miller, Mark C. [Orthopaedic Biomechanics Research Laboratory, Allegheny General Hospital, Pittsburgh, PA 15212 (United States); Gawalt, Ellen S., E-mail: gawalte@duq.edu [Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA 15282 (United States); McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219 (United States)

2016-08-01

A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0–5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (> 180%) and proliferation (> 140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (> 99.6% after 24 h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

Reducing Escherichia coli growth on a composite biomaterial by a surface immobilized antimicrobial peptide

International Nuclear Information System (INIS)

Buckholtz, Gavin A.; Reger, Nina A.; Anderton, William D.; Schimoler, Patrick J.; Roudebush, Shana L.; Meng, Wilson S.; Miller, Mark C.; Gawalt, Ellen S.

2016-01-01

A new composite bioceramic consisting of calcium aluminum oxide (CaAlO) and hydroxyapatite (HA) was functionalized with the synthetic antimicrobial peptide Inverso-CysHHC10. CaAlO is a bioceramic that can be mold cast easily and quickly at room temperature. Improved functionality was previously achieved through surface reactions. Here, composites containing 0–5% HA (by mass) were prepared and the elastic modulus and modulus of rupture were mechanically similar to non-load bearing bone. The addition of hydroxyapatite resulted in increased osteoblast attachment (> 180%) and proliferation (> 140%) on all composites compared to 100% CaAlO. Antimicrobial peptide (AMP) immobilization was achieved using an interfacial alkene-thiol click reaction. The linked AMP persisted on the composite (> 99.6% after 24 h) and retained its activity against Escherichia coli based on N-phenylnaphthylamine uptake and bacterial turbidity tests. Overall, this simple scaffold system improves osteoblast activity and reduces bacterial activity. - Highlights: • Calcium aluminum oxide and hydroxyapatite were cast into a composite material. • Osteoblast attachment and proliferation were significantly increased on composites. • An active antimicrobial peptide was linked to and remained stable on the composite. • Bacterial turbidity and NPN uptake tests showed modified composites had an effect equal to a 10 μM Inverso-CysHHC10 solution. • Antimicrobial peptide linkage did not affect the increased osteoblast performance.

Effect of wood ash application on soil solution chemistry of tropical acid soils: incubation study.

Science.gov (United States)

Nkana, J C Voundi; Demeyer, A; Verloo, M G

2002-12-01

The objective of this study was to determine the effect of wood ash application on soil solution composition of three tropical acid soils. Calcium carbonate was used as a reference amendment. Amended soils and control were incubated for 60 days. To assess soluble nutrients, saturation extracts were analysed at 15 days intervals. Wood ash application affects the soil solution chemistry in two ways, as a liming agent and as a supplier of nutrients. As a liming agent, wood ash application induced increases in soil solution pH, Ca, Mg, inorganic C, SO4 and DOC. As a supplier of elements, the increase in the soil solution pH was partly due to ligand exchange between wood ash SO4 and OH- ions. Large increases in concentrations of inorganic C, SO4, Ca and Mg with wood ash relative to lime and especially increases in K reflected the supply of these elements by wood ash. Wood ash application could represent increased availability of nutrients for the plant. However, large concentrations of basic cations, SO4 and NO3 obtained with higher application rates could be a concern because of potential solute transport to surface waters and groundwater. Wood ash must be applied at reasonable rates to avoid any risk for the environment.

Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

Directory of Open Access Journals (Sweden)

Ugur Erdemir

2013-04-01

Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

Natural cork agglomerate employed as an environmentally friendly solution for quiet sandwich composites.

Science.gov (United States)

Sargianis, James; Kim, Hyung-ick; Suhr, Jonghwan

2012-01-01

Carbon fiber-synthetic foam core sandwich composites are widely used for many structural applications due to their superior mechanical performance and low weight. Unfortunately these structures typically have very poor acoustic performance. There is increasingly growing demand in mitigating this noise issue in sandwich composite structures. This study shows that marrying carbon fiber composites with natural cork in a sandwich structure provides a synergistic effect yielding a noise-free sandwich composite structure without the sacrifice of mechanical performance or weight. Moreover the cork-core sandwich composites boast a 250% improvement in damping performance, providing increased durability and lifetime operation. Additionally as the world seeks environmentally friendly materials, the harvesting of cork is a natural, renewable process which reduces subsequent carbon footprints. Such a transition from synthetic foam cores to natural cork cores could provide unprecedented improvements in acoustic and vibrational performance in applications such as aircraft cabins or wind turbine blades.

Prediction of the effects of soil-based countermeasures on soil solution chemistry of soils contaminated with radiocesium using the hydrogeochemical code PHREEQC.

Science.gov (United States)

Hormann, Volker; Kirchner, Gerald

2002-04-22

For agriculturally used areas, which are contaminated by the debris from a nuclear accident, the use of chemical amendmends (e.g. potassium chloride and lime) is among the most common soil-based countermeasures. These countermeasures are intended to reduce the plant uptake of radionuclides (mainly 137Cs and 90Sr) by competitive inhibition by chemically similar ions. So far, the impacts of countermeasures on soil solution composition - and thus, their effectiveness - have almost exclusively been established experimentally, since they depend on mineral composition and chemical characteristics of the soil affected. In this study, which focuses on caesium contamination, the well-established code PHREEQC was used as a geochemical model to calculate the changes in the ionic compositions of soil solutions, which result from the application of potassium or ammonium in batch equilibrium experiments. The simple ion exchange model used by PHREEQC was improved by taking into account selective sorption of Cs+, NH4+ and K+ by clay minerals. Calculations were performed with three different initial soil solution compositions, corresponding to particular soil types (loam, sand, peat). For loamy and sandy soils, our calculational results agree well with experimental data reported by Nisbet (Effectiveness of soil-based countermeasures six months and one year after contamination of five diverse soil types with caesium-134 and strontium-90. Contract Report NRPB-M546, National Radiation Protection Board, Chilton, 1995.). For peat, discrepancies were found indicating that for organic soils a reliable set of exchange constants of the relevant cations still has to be determined experimentally. For cesium, however, these discrepancies almost disappeared if selective sites were assumed to be inaccessible. Additionally, results of sensitivity analyses are presented by which the influence of the main soil parameters on Cs+ concentrations in solution after soil treatment has been systematically

Variation in essential oil composition within individual leaves of sweet basil (Ocimum basilicum L.) is more affected by leaf position than by leaf age.

Science.gov (United States)

Fischer, Ravit; Nitzan, Nadav; Chaimovitsh, David; Rubin, Baruch; Dudai, Nativ

2011-05-11

The aroma in sweet basil is a factor affecting the commercial value of the crop. In previous studies leaf age was considered to be a factor that influences the composition of essential oil (EO). In this study it was hypothesized that a single observation of the EO content in leaves from different positions on the main stem (young vs old) could predict the developmental changes in the plant during its life cycle. Plants harvested at week 16 demonstrated an exponential increase (R(2) = 0.92) in EO concentration in leaves on the main stem and lateral shoots, indicating higher EO concentrations in younger than in older leaves. Eugenol and methyleugenol predominated (28-77%) in the extract. Eugenol levels were higher in younger leaves (∼53%), and methyl-eugenol levels predominated in older leaves (∼68%). Linalool was lower in mature leaves than in younger leaves. This suggested that eugenol converted into methyleugenol and linalool decreased as leaf mature. However, in weekly monitored plants, the levels of these compounds in the EO had limited variation in the maturing leaf regardless of its position on the stem. This proposed that the EO composition in an individual leaf is mostly affected by the leaf position on the stem and not by its maturation process. Because leaf position is related to plant development, it is probable that the plant's physiological age at the time of leaf formation from the primordial tissue is the factor affecting the EO composition. It was concluded that interpretation of scientific observations should be carried out with caution and that hypotheses should be tested utilizing multifaceted approaches.

Method for Cs-137 separation from the decontamination solutions

International Nuclear Information System (INIS)

Toropov, I.G.; Efremenkov, V.M.; Toropova, V.V.; Satsukevich, V.M.; Davidov, Yu.P.

1995-01-01

In this work results of investigations are presented on separation of radiocaesium from the decontamination solutions containing reducing agents (thiocarbamide). The scientific basis for radiocaesium removal from the solution focuses on the state of the radionuclide and its sorption behavior in the solution with a complicated composition. Then using a combination of sorption and ultrafiltration methods it would be possible to concentrate the radionuclide in a small volume and to purify the main part of the solution. As a sorbent for radiocaesium removal from the solution, a ferrocyanide based sorbent is proposed. Use of this sorbent is justified since its high selectivity and effectiveness for radiocaesium sorption from the solutions of different composition is well known. When synthesis of the sorbent is performed directly in the treating solution, two components as a minimum should be added to it, namely K 4 Fe(CN) 6 and metal ions of Ni-II, Co-II, Cu-II, etc. The results are presented which show the possibility of radiocaesium separation from the decontamination solutions (containing 60--100 g/l of salts) using sorption and membrane separation methods without the use of metal salts. At the same time by using FE-2 in solution in the presence of cyanide ions and thiocarbamide, it is possible to avoid the addition of metal salts (Ni, Cu, etc.). Utilization of the proposed method for spent decontamination solution treatment allows a relatively easy way to reduce the concentration of radiocaesium in solution on 2--4 orders of magnitudes, and to exclude the utilization of relatively expensive metal salts

Synthesis, processing and characterization of shear thickening fluid (STF) impregnated fabric composites

International Nuclear Information System (INIS)

Hassan, Tarig A.; Rangari, Vijay K.; Jeelani, Shaik

2010-01-01

Shear thickening is a non-Newtonian fluid behavior defined as the increase of viscosity with the increase in the applied shear rate. The shear thickening fluid (STF) is a combination of hard metal oxide particles suspended in a liquid polymer. This mixture of flowable and hard components at a particular composition, results in a material with remarkable properties. In this manuscript the shear thickening fluid (STF) was prepared by ultrasound irradiation of silica nanoparticles dispersed in liquid polyethylene glycol polymer. The as-prepared STFs have been tested for their rheological and thermal properties. Kevlar and Nylon fabrics were soaked in STF/ethanol solution to make STF/fabric composite. Knife threats and quasistatic penetration tests were performed on the neat fabrics and STF/fabric composite targets for both engineered spike and knife on areal density basis. The results showed that STF impregnated fabrics have better penetration resistance as compared to neat fabrics without affecting the fabric flexibility. This indicates that the addition of STF to the fabric have enhanced the fabric performance and can be used in liquid body armor applications.

Influence of high loading of cellulose nanocrystals in polyacrylonitrile composite films

Science.gov (United States)

Jeffrey Luo; Huibin Chang; Amir A. Bakhtiary Davijani; H. Clive Liu; Po-Hsiang Wang; Robert J. Moon; Satish Kumar

2017-01-01

Polyacrylonitrile-co-methacrylic acid (PAN-co-MAA) and cellulose nanocrystal (CNC) composite films were produced with up to 40 wt% CNC loading through the solution casting method. The rheological properties of the solution/suspensions and the structural, optical, thermal, and mechanical properties of the resulting films were investigated. The viscosity of the composite...

Radiolysis of spray solutions

International Nuclear Information System (INIS)

Habersbergerova, A.; Janovsky, I.

1985-01-01

The factors were studied affecting thiosulfate radiolysis in the so-called spray solution for nuclear power plant containments. The reaction mechanism of primary radiolytic reactions leading to thiosulfate decomposition was studied using pulse radiolysis. Also measured was hydrazine loss in the irradiation of the bubbling solution intended for the capture of volatile chemical forms of radioiodine. Pulse radiolysis was used to study the kinetics of hydrazine reaction with elemental iodine. (author)

Balancing Modularity and Solution Space Freedom

DEFF Research Database (Denmark)

Vos, Maren A.; Raassens, Néomie; Van der Borgh, Michel

2018-01-01

that modularity reflects knowledge specialisation and solution space freedom reflects knowledge variety. Both of these dimensions affect organisational learning and, in turn, sustainable innovation. Second, we argue that the relationship between customisation and organisational learning is affected by supplier...... theory to provide insights into how TI firms can achieve ‘win-win’ situations where sustainable innovation is increased through customisation. First, we argue that customisation should be viewed two-dimensionally and identify both modularity and solution space freedom as important dimensions. We argue...... characteristics, specifically supplier sophistication. Survey data from 166 managers were used to empirically test the conceptual model and hypotheses. Polynomial response surface analysis confirms that customising by balancing high degrees of both modularity and solution space freedom results in superior...

Effect of monomer composition on the properties of high temperature polymer concretes

Energy Technology Data Exchange (ETDEWEB)

Zeldin, A.; Kukacka, L.E.; Carciello, N.

1980-01-01

The effects of organic monomer composition on the thermomechanical properties of polymer concrete (PC) containing sand-cement mixtures as an agregate filler were investigated. The effects of various monomer mixtures on compressive strength and hydrolytic stability are discussed. Composites were fabricated in the same way as ordinary concrete, with monomer solutions of various compositions and concentrations used to bind the sand-cement mixture. The compressive strengths of th composites before and after exposure to air and to brine solutions at 240/sup 0/C are discussed.

In situ polymerization of monomers for polyphenylquinoxaline/graphite fiber composites

Science.gov (United States)

Serafini, T. T.; Delvigs, P.; Vannucci, R. D.

1974-01-01

Methods currently used to prepare fiber reinforced, high temperature resistant polyphenylquinoxaline (PPQ) composites employ extremely viscous, low solids content solutions of high molecular weight PPQ polymers. An improved approach, described in this report, consists of impregnating the fiber with a solution of the appropriate monomers instead of a solution of previously synthesized high molecular weight polymer. Polymerization of the monomers occurs in situ on the fiber during the solvent removal and curing stages. The in situ polymerization approach greatly simplifies the fabrication of PPQ graphite fiber composites. The use of low viscosity monomeric type solutions facilitates fiber wetting, permits a high solids content, and eliminates the need for prior polymer synthesis.

Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions. Chemical composition range and flux crystal growth

Energy Technology Data Exchange (ETDEWEB)

Ivanov, V.A. [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation); Marychev, M.O., E-mail: marychev@yandex.ru [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation); Andreev, P.V.; Lykov, V.A.; Faddeev, M.A. [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation); Koseva, I. [Bulgarian Academy of Science, Institute of General and Inorganic Chemistry, BU-1113 Sofia (Bulgaria); Nikolov, V. [N.I. Lobachevsky State University of Nizhni Novgorod, Nizhni Novgorod, 603950 (Russian Federation)

2015-11-01

A series of Ca{sub 2−x}Li{sub 2x}GeO{sub 4} specimens with 0 < 2x < 2, were synthesized by the classical solid state method. X-ray analysis revealed that for 0 < 2x < 0.6 only Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions of Ca{sub 2}GeO{sub 4} structure crystallized. The cell parameters of these solid solutions linearly decreased upon increasing the lithium concentration, which means that the solutions are in accordance with the Vegard's law. For 2x > 0.6 the specimens contained two phases: (i) Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions with maximum lithium concentration approximately equal to that for 2x = 0.6 and minimum values of the cell parameters and (ii) Li{sub 2}CaGeO{sub 4} phase. Li{sub 2}O·MoO{sub 3}–Ca{sub 2}GeO{sub 4} high-temperature solutions were used to grow Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions and Li{sub 2}CaGeO{sub 4} single crystals by the high temperature solution (flux) method. Li{sub 2}CaGeO{sub 4} crystals were grown in the concentration range 8–26 wt. % Ca{sub 2}GeO{sub 4} in the temperature range 830–980 °C. Crystals with chemical compositions of the Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions with different Li concentrations were grown in the concentration range 26–40 wt. % Ca{sub 2}GeO{sub 4} in the temperature range 980–1090 °C. - Highlights: • Ca{sub 2−x}Li{sub 2x}GeO{sub 4} solid solutions are established for the first time. • The Li concentration range into the solutions is between 0 and 0.6. • The solid solutions are in accordance to Vegard's law. • Suitable solutions are found out for Ca{sub 2−x}Li{sub 2x}GeO{sub 4} and Li{sub 2}CaGeO{sub 4} crystal growth.

Investigation of the removal of chromium (VI by Nanocomposites Chitosan-tragacanth solution from aqueous solution

Directory of Open Access Journals (Sweden)

Adel Almasi Nahnaji

2016-03-01

Full Text Available Background: The aim of this study was to investigate the removal of chromium (VI by Nanocomposites Chitosan-tragacanth solution from aqueous solution. Methods: In this study, chitosan-tragacanth nanocomposites were synthesized and analyzed by electron microscopy (SEM, (TEM and Fourier transform spectroscopy (FT-IR for the size and shape of the surface. The nano-composite of chitosan-tragacanth, for the adsorption of chromium (VI in aqueous solution was used as adsorbent. Results: The optimum conditions with multiple experiments to enhance the absorption were evaluated. The highest absorption of Cr (VI was occurred in the adsorbent dosage of 0.2 g, 8 ppm concentration of chromium ions, the pH=6 and also retention time of 50 min; in 298 ˚K temperature. After determining optimal conditions of adsorption, isotherms equations and study and thermodynamic parameters were applied. Adsorption process of chromium (VI on nano-composite chitosan - Tragacanth was conformed with Temkin isotherm. Conclusion: The thermodynamic parameters such as standard Gibbs free energy changes, changes in enthalpy and entropy changes in the standard showed that the adsorption process of Cr (VI is spontaneous and heating, and kinetics studies of models Lagergren, Ho , Alovich and intraparticle is used, the results show that the adsorption kinetics follows the pseudo-second order.

Factors and mechanisms affecting corrosion of steel in concrete

International Nuclear Information System (INIS)

Dehqanian, Ch.

1986-01-01

Atomic power plants possess reinforced concrete structures which are exposed to sea water or sea atmosphere. Sea water or its surrounding environment contain very corrosive species which cause corrosion of metal in concrete. It should be mentioned that corrosion of steel in concrete is a complex problem that is not completely understood. Some of the factors which influence the corrosion mechanism and can be related to the pore solution composition is discussed. Chloride ion caused problems are the main source of the corrosion damage seen on the reinforced concrete structures. Corrosion rate in concrete varies and depends on the way chloride ion diffuses into concrete. In addition, the associated cations can influence diffusion of chloride into concrete. The type of portland cement and also the concrete mix design all affect the corrosion behaviour of steel in concrete

Study of the chemical composition of waters in Morro do Ferro (MG), Brazil: transport of thorium and several tracer alements in solution

International Nuclear Information System (INIS)

Pivetta, F.R.

1983-01-01

The chemical composition of surface and well waters in the Morro do Ferro (Pocos de Caldas-MG.) Brazil, because the transport in solution may represent one important way of environmental contamination is studied. Samples of one stream in the base of the hill, of perfuration wells and of one galery were analysed in the period from 1980 (October) to 1982 (May). The contents of Mn, Fe, SiO 2 , SO 2- 4 , PO 3- 4 , NO - 3 and CO 2 is analysed in situ. (M.J.C.) [pt

Composite Materials in Overhead Lines

DEFF Research Database (Denmark)

Sørensen, Thomas Kjærsgaard; Holbøll, Joachim

2009-01-01

towers and recently conductors based on composite materials are available at transmission levels. In this paper it is investigated which composite based solutions are available in connection with complete overhead line systems including insulators, towers and conductors. The components are reviewed......The use of composite materials, e.g. fibreglass materials, in overhead transmission line systems is nothing new. Composite based insulators have been applied to transmission lines for over 30 years, mainly as suspension and post insulators and often as an option for special applications. Also...... with respect to solved and persisting known failures/problems of both mechanical and electrical nature. Major challenges related to extensive use of composite materials in an overhead line system are identified, as are possible benefits - both when using standard as well as customised composite components, e...

A probabilistic approach towards understanding how planet composition affects plate tectonics - through time and space.

Science.gov (United States)

Stamenkovic, V.

2017-12-01

We focus on the connections between plate tectonics and planet composition — by studying how plate yielding is affected by surface and mantle water, and by variable amounts of Fe, SiC, or radiogenic heat sources within the planet interior. We especially explore whether we can make any robust conclusions if we account for variable initial conditions, current uncertainties in model parameters and the pressure dependence of the viscosity, as well as uncertainties on how a variable composition affects mantle rheology, melting temperatures, and thermal conductivities. We use a 1D thermal evolution model to explore with more than 200,000 simulations the robustness of our results and use our previous results from 3D calculations to help determine the most likely scenario within the uncertainties we still face today. The results that are robust in spite of all uncertainties are that iron-rich mantle rock seems to reduce the efficiency of plate yielding occurring on silicate planets like the Earth if those planets formed along or above mantle solidus and that carbon planets do not seem to be ideal candidates for plate tectonics because of slower creep rates and generally higher thermal conductivities for SiC. All other conclusions depend on not yet sufficiently constrained parameters. For the most likely case based on our current understanding, we find that, within our range of varied planet conditions (1-10 Earth masses), planets with the greatest efficiency of plate yielding are silicate rocky planets of 1 Earth mass with large metallic cores (average density 5500-7000 kg m-3) with minimal mantle concentrations of iron (as little as 0% is preferred) and radiogenic isotopes at formation (up to 10 times less than Earth's initial abundance; less heat sources do not mean no heat sources). Based on current planet formation scenarios and observations of stellar abundances across the Galaxy as well as models of the evolution of the interstellar medium, such planets are

What Affects the Isotopic Composition of Precipitation - A New Interpretation?

Energy Technology Data Exchange (ETDEWEB)

Dody, A. [Nuclear Research Center, Negev, Beer Sheva (Israel)

2013-07-15

Rainfall events were sampled in high resolution for stable isotope analyses during four rainy seasons in the central negev of Israel. Each sample is equivalent to 1-2 mm of rain. High variability in the isotopic composition was found in fractions of rain during storms. Two modes of isotopic distribution were found. The first is a wave shaped distribution, where isotopic compositions showed enriched to depleted graded changes and vice versa. The second mode is a step function where each rain cell displayed a constant {delta}{sup 18}O value, but varied greatly from the other rain cells. New interpretation suggests that during the transport of the air parcel system three processes can occur. The first process is a complete blending among the rain cells. The second is a partial isotopic mixing between the rain cells. Finally the third case is when each rain cell maintains its own isotopic values separate from the other rain cells. The third case of no mixing showed unexpected results due to the high air turbulence, vertically and horizontally. There was no evidence of complete mixing among the rain cells of identical air parcel systems. The processes in the air parcel trajectory itself suggested here is put forward as a new way to explain the changes in the isotopic composition during the rain. (author)

Composite films of poly-(ester-sulphonated) and poly-(3-methylthiophene) for ion-exchange voltammetry in acetonitrile solutions

International Nuclear Information System (INIS)

Scopece, Paolo; Moretto, Ligia M.; Polizzi, Stefano; Ugo, Paolo

2006-01-01

This paper describes the preparation and characterisation of a polymeric electrode coating based on a composite of the poly-(ester-sulphonated) Eastman AQ55[reg] (AQ55) and poly-(3-methylthiophene) (PMeT), which is used for the controlled uptake and partial release of electroactive cations in acetonitrile solutions. The film is prepared by electrochemical oxidation in acetonitrile of 3-methylthiophene on glassy carbon disks or Pt-quartz crystal electrodes pre-coated with a thin film of AQ55. The electropolymerisation process is controlled so that the overall number of positive charges of oxidised PMeT is equal to the number of negative charges of the sulphonate groups of AQ55. Cyclic voltammetry and quartz crystal microbalance measurements indicate that the AQ55/PMeT mixed film is stable in acetonitrile and that its cation-exchange properties depend on the applied potential. When the PMeT moieties are reduced, the film incorporate cations; following electrochemical oxidation of the coating causes a release of the incorporated cations which, however, is only partial. Scanning electron microscopy (SEM) examination of cross sections of the composite polymer layer indicate that it is really a bi-layer, made by an inner compact layer of AQ55 on which a thicker and porous PMeT layer is grown. The outer PMeT layer acts as a barrier whose ionic charges can be changed electrochemically from positive (oxidation) to neutral (reduction). These ionic charges hinder or allow, respectively, the permeation of redox cations which tend to interact with the negatively charged sulphonic sites of the AQ55 layer. Direct self-neutralization of part of the positive charges of oxidized PMeT by the AQ55 sulphonic groups allows the release of part of the redox cations incorporated previously in the mixed film when PMeT is in the reduced state. By operating in acetonitrile solutions without added electrolyte it is possible to increase the fraction of redox cations which are released in

[Effect of bleaching agents on the color of indirect and direct composite resins].

Science.gov (United States)

Xing, Wenzhong; Jiang, Tao; Chen, Xiaodong; Wang, Yining

2014-09-01

To evaluate the effect of bleaching agents on the color of indirect and direct composite resins. Five resin composite materials were tested in this in vitro study. The five composites were as follow: two indirect composite resins (Adoro SR, Ceramage) and three direct composite resins (Filtek Z350, Clearfil Majesty Esthetic, and Gradia Direct Anterior). For each material, twenty disk-shaped specimens were prepared and randomly divided into five groups according to the color parameters of specimens before bleaching treatment. The composite resin specimens were treated by one of five sample solutions which were at-home bleaching agents (10% and 15% carbarmide peroxide), in- office bleaching agents (38% H(2)O(2) and 35%H(2)O(2)) and deionized water (control group). The color parameters of specimens were measured by spectrophotometer at baseline and after bleaching treatments. The color differences (ΔE values) between baseline and post-treatments were calculated. The data of color differences were evaluated statistically using two-way analysis with a significance level of 0.05. The color changes of the resin composites were less than 2.0 after bleaching agent treatment, therefore were not perceptible. Slight increase of L(*) values and decrease of C(*)ab values in color parameters of specimens were observed. There were statistically significant differences in ΔE values for different bleaching treatments and resin materials (P = 0.001). The bleaching agents did not affect the color of indirect and direct composite resins tested.

Preparation and characterization of polyaniline-copper composites by electrical explosion of wire.

Science.gov (United States)

Liu, Aijie; Bac, Luong Huu; Kim, Jin-Chun; Liu, Lizhu

2012-07-01

Polyaniline-copper composites with a polyacrylic acid (PAA) were synthesized by electrical explosion of wire. Polyaniline (PANI) and PAA were put into the explosion medium, deionized water (DIW) and ethanol, stirred for 24 hrs and sonicated for 2 hrs. These solutions were used as base liquids for explosion process to fabricate Cu nanoparticle. Optical absorption in the UV-visible region of PANI and PANI/PAA-Cu composites was measured in a range of 200-900 nm. X-ray diffraction was used to analyze the phase of the composites. XRD pattern showed the PANI was amorphous and copper was polycrystalline. Two phases of Cu and Cu2O were formed in aqueous solution while single Cu phase was obtained in ethanol solution. Field emission scanning electron microscope was used to observe the microstructure of the composites. The synthesized composites were extensively characterized by Fourier Transform Infrared (FTIR) spectroscopy and electrical measurements.

Survival and growth of Enterobacter sakazakii in infant cereal as affected by composition, reconstitution liquid, and storage temperature.

Science.gov (United States)

Lin, Li-Chun; Beuchat, Larry R

2007-06-01

Invasive infections caused by Enterobacter sakazakii have occurred predominantly in low-birth-weight neonates and infants younger than 2 months of age. However, infections have also occurred in healthy infants up to 8 months of age and in immunocompromised children up to 4 years of age. The ability of E. sakazakii to survive and grow in infant cereals as affected by composition of the cereal, composition of the reconstitution liquid, and temperature is unknown. A study was done to determine the survival and growth characteristics of E. sakazakii initially at populations of 0.005 and 0.52 CFU/ml of infant rice cereal, oatmeal cereal, or rice with mixed fruit cereal reconstituted with water, milk, or apple juice. Reconstituted cereals were stored at 4, 12, 21, and 30 degrees C, and populations were monitored for up to 72 h. Growth did not occur in reconstituted cereals stored at 4 degrees C or in cereals reconstituted with apple juice and stored at 12 degrees C. Populations (> or =1 CFU/ml) were detected in cereals reconstituted with water or milk and stored at 12, 21, and 30 degres C for 24, 8, and 4 h, respectively. The composition of infant cereals did not markedly affect the survival or growth of E. sakazakii in reconstituted cereals. Populations of E. sakazakii in reconstituted cereal decreased with increases in populations of mesophilic aerobic microflora up to 8 to 9 log CFU/ml, which was concurrent with decreases in pH. E. sakazakii, initially at 2.62 log CFU/ml of rice cereal reconstituted with apple juice (pH 4.32), survived at 40C for at least 14 days. The pathogen grew at 21 and 30 degrees C within 2 days and then decreased to undetectable levels (<1 CFU/10 ml) in cereal stored at 21 degrees C for 5 days or 30'C for 4 days. Initially, at 7.32 log CFU/ml, E. sakazakii was detected in rice cereal stored at 4 degrees C for 50 days. It is recommended that reconstituted infant cereals stored at 21 or 30 degrees C be discarded within 4 h after preparation or

Adsorptive molecularly imprinted composite membranes for chiral separation of phenylalanine

Directory of Open Access Journals (Sweden)

Shah Nasrullah

2016-09-01

Full Text Available Two types of composite imprinted membranes, i.e., composite membrane comprised of D-Phe imprinted beads and D-Phe imprinted membrane or DCM and composite membrane comprised of L-Phe imprinted beads and L-Phe imprinted membranes or LCM, were synthesized by phase inversion technique after a uniform dispersion of beads within the polymeric solutions using simple physico-mechanical process. The assemblies of the prepared DCM, LCM and control membranes were employed in ultrafiltration for chiral separation of D, L-Phenylalanine racemate solution. DCM and LCM showed an improved adsorption capacity (0.334 mg g-1 and 0.365 mg g-1 respectively, and adsorption selectivity (2.72 and 2.98 respectively. However, the percent rejection of the template and counter enantiomer were lower than that of control membranes. Compared to control membrane, the DCM and LCM showed inverse permselectivity. These composite membranes having better adsorption and separation ability for Phenylalanine racemate solution will be suitable in the future for various other applications.

Composition for use in scintillator systems

International Nuclear Information System (INIS)

Tarkkanen, V.

1976-01-01

A liquid scintillation counting composition of the type comprising an aromatic hydrocarbon solvent, an ethoxylated alkyl phenol surfactant, and a scintillation solute, containing a small amount of a substituted ethoxylated carboxylate acid and/or a tertiary amine salt or a quaternary ammonium salt of such acid is described. The free acid reduces chemiluminescence upon the addition of an alkaline sample to the composition, while the tertiary amine or quaternary ammonium salt enhances the water miscibility of the composition

Synthesis of high-performance Li2FeSiO4/C composite powder by spray-freezing/freeze-drying a solution with two carbon sources

Science.gov (United States)

Fujita, Yukiko; Iwase, Hiroaki; Shida, Kenji; Liao, Jinsun; Fukui, Takehisa; Matsuda, Motohide

2017-09-01

Li2FeSiO4 is a promising cathode active material for lithium-ion batteries due to its high theoretical capacity. Spray-freezing/freeze-drying, a practical process reported for the synthesis of various ceramic powders, is applied to the synthesis of Li2FeSiO4/C composite powders and high-performance Li2FeSiO4/C composite powders are successfully synthesized by using starting solutions containing both Indian ink and glucose as carbon sources followed by heating. The synthesized composite powders have a unique structure, composed of Li2FeSiO4 nanoparticles coated with a thin carbon layer formed by the carbonization of glucose and carbon nanoparticles from Indian ink. The carbon layer enhances the electrochemical reactivity of the Li2FeSiO4, and the carbon nanoparticles play a role in the formation of electron-conducting paths in the cathode. The composite powders deliver an initial discharge capacity of 195 and 137 mAh g-1 at 0.1 C and 1 C, respectively, without further addition of conductive additive. The discharge capacity at 1 C is 72 mAh g-1 after the 100th cycle, corresponding to approximately 75% of the capacity at the 2nd cycle.

Variations in the chemical composition of the solution extracted from a Latosol under fertigation with vinasse

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João Paulo Francisco

2016-06-01

Full Text Available ABSTRACT The aim of this work was to evaluate the change in electrical conductivity and pH of a soil solution and its composition, with regard to the levels of nitrate and potassium, in a Latosol cultivated with pineapple and subjected to applications of different levels of vinasse. The experiment was conducted in a greenhouse at the Department of Biosystems Engineering of ESALQ/USP. The treatments comprised the application of five levels of vinasse: T1 - 0 m3 ha-1, T2 - 231 m3 ha-1, T3 - 347 m3 ha-1, T4 - 462 m3 ha-1, and T5 - 578 m3 ha-1. Application was every 20 days, using a localised irrigation system with emitters having a nominal flow rate of 4 L h-1 and spaced 0.40 m apart. The applied doses of vinasse were calculated by following the recommendations of CETESB standard P4.231, so that treatment T4 would supply the demand of the pineapple plant for potassium. The solution was collected by means of porous capsule extractors at 30, 120 and 210 days from the start of vinasse application. It was found that increases in the volume of the applied levels resulted in greater values for the electrical conductivity of the soil (ECs and in the concentration of potassium (K and nitrate (NO3, with higher values being obtained in the 0.20 m layer. The results demonstrated that pH decreased with increases in the vinasse being applied.

Effect of Ingested Liquids on Color Change of Composite Resins.

Science.gov (United States)

Malek Afzali, Beheshteh; Ghasemi, Amir; Mirani, Asrin; Abdolazimi, Zahra; Akbarzade Baghban, Alireza; Kharazifard, Mohammad Javad

2015-08-01

Color change of composite restorations is well known to dentists. However, the effect of commonly consumed drinks on discoloration of composite resins has yet to be determined. This study sought to assess the color change of a nanofilled (Premise) and a flowable composite resin (Premise flowable) following simulated consumption of tea, cola, iron drops and multivitamin syrup. Forty disk-shaped specimens (7 mm in diameter and 2 mm thick) were fabricated from each composite resin. The baseline color values were measured according to the CIE L*a*b* system using digital imaging. The specimens of each restorative material were randomly divided into five groups (eight each) according to the storage media namely tea, cola, iron drops, multivitamin syrup or distilled water (control). The specimens were immersed in staining solutions for three hours daily over a 40-day test period. Following this, the color change values (ΔE*) were calculated. For statistical analyses, the color differences were analyzed using two-way ANOVA and Tukey's test (Pcomposite resins (P>0.05). In both composite materials, the difference among the solutions was not significant (P>0.05). Under the tested experimental conditions, both restorative materials were susceptible to discoloration by all four staining solutions. The color change values were not related to the solution or the type of material used.

Geological constraints on the thermodynamic properties of the stilbite - stellerite solid solution in low-grade metabasalts

Science.gov (United States)

Fridriksson, Thráinn; Neuhoff, Philip S.; Arnórsson, Stefán; Bird, Dennis K.

2001-11-01

Standard state thermodynamic data for stilbite (Ca2NaAl5Si13O36∗16H2O) and stellerite (Ca2Al4Si14O36∗14H2O), together with mixing properties of the stilbite -stellerite solid solution (stilbite SS) are derived through assessment of geological observations of stilbite SS compositions in metabasalts, experimental phase equilibria, and calorimetric observations. Measured compositions of stilbite SS in Tertiary metabasalts in Iceland and Icelandic geothermal systems change systematically towards the stellerite endmember with increasing stratigraphic depth and temperature. Standard molal volumes, heat capacities, and entropies for the endmembers of the solid solution are derived through critical review of published crystallographic and calorimetric data for natural stilbite SS. Standard molal Gibbs energies of formation at 298.15 K and 1 bar for stilbite (-4,946,475cal mol-1) and stellerite (-4,762,036 cal mol-1) and the mixing properties of the solid solution are retrieved from observed phase- and compositional-relations in metabasalts at Berufjördur, Iceland, measured temperatures of zeolite mineral distribution in active geothermal systems, and published observations of reversed phase equilibria. Mixing in stilbite SS can be described with an athermal solid solution model. Thermodynamic data resulting from our analysis provide close correlation between compositions of stilbite SS in Icelandic geothermal systems predicted from compositions of geothermal solutions and observed compositions of these minerals in low-grade metabasalts of Iceland, as well as the observed temperature of the stilbite SS to laumontite (leonhardite) transition in Icelandic geothermal systems. Stilbite SS composition in metabasalts is a sensitive function of temperature, fluid composition, coexisting minerals (especially silica polymorphs) and geothermal gradient.

Intercomparison of Cement Solid-Solution Models. Issues Affecting the Geochemical Evolution of Repositories for Radioactive Waste

International Nuclear Information System (INIS)

Benbow, Steven; Savage, David; Walker, Colin

2007-05-01

Many concepts for the geological storage of radioactive waste incorporate cement based materials, which act to provide a chemical barrier, impede groundwater flow or provide structural integrity of the underground structures. Thus, it is important to understand the long-term behaviour of these materials when modelling scenarios for the potential release and migration of radionuclides. In the presence of invasive groundwater, the chemical and physical properties of cement, such as its pH buffering capacity, resistance to flow, and its mechanical properties, are expected to evolve with time. Modelling the degradation of cement is complicated by the fact that the long term pH buffer is controlled by the incongruent dissolution behaviour of calcium-silicate-hydrate (C-S-H) gel. It has been previously shown (SKI Report 2005:64) that it is possible to simulate the long term evolution of both the physical and chemical properties of cement based materials in an invasive groundwater using a fully coupled geochemical transport model. The description of the incongruent dissolution of C-S-H gel was based on a binary solid solution aqueous solution (SSAS) between end-member components portlandite (Ca(OH) 2 ) and a C-S-H gel composition expressed by its component oxides (CaH 2 SiO 4 ). The models considered a range of uncertainties including different groundwater compositions, parameterised couplings between the evolution of porosity with permeability and diffusivity and alternative secondary mineral assemblages. The results of the modelling suggested that alternative evolutions were possible under these different conditions. The focus of this report is to address the uncertainty regarding the choice of model for the C-S-H gel dissolution. We compare two alternative C-S-H SSAS models with the one that was used in the previous report, with an emphasis on a direct comparison of the model predictions. Thus we have chosen one simple simulated experimental model based on those in the

Photocatalytic degradation of organic dyes using composite nanofibers under UV irradiation

Science.gov (United States)

Salama, Ahmed; Mohamed, Alaa; Aboamera, Nada M.; Osman, T. A.; Khattab, A.

2018-02-01

In this work, photocatalytic degradation of organic dyes such as methylene blue (MB) and indigo carmine (IC) have been studied by composite nanofibers systems containing cellulose acetate (CA), multiwall carbon nanotubes (CNT) and TiO2 nanoparticles under UV light. The amino factionalized TiO2-NH2 NPs cross-linked to the CA/CNT composite nanofibers works as a semiconductor catalyst. The morphology and crystallinity were characterized by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction, and Fourier transform infrared spectroscopy. It was also seen that many factors affected the photodegradation rate, mainly the pH of the solution and the dye concentration, temperature, etc. The study demonstrated that IC degrades at a higher rate than MB. The maximum photodegradation rate of both organic dyes was achieved at a pH 2. In comparison to other studies, this work achieved high photodegradation rate in lower time and using less power intensity.

Effects of Composition and Calcination Temperature on Photocatalytic Evolution over from Glycerol and Water Mixture

Directory of Open Access Journals (Sweden)

Cancan Fan

2012-01-01

Full Text Available A series of sulfide coupled semiconductors supported on SiO2, (, was prepared by incipient wet impregnation method. The photocatalysts were characterized by XRD, XPS, TPR, and UV/Vis DRS. Characterization results show that the chemical actions between ZnS and CdS resulted in the formation of solid solutions on the surface of the support and the formation of them is affected by the molar ratio of ZnS/CdS and calcination temperature. Performance of photocatalysts was tested in the home made reactor under both UV light and solar-simulated light irradiation by detecting the rate of the photocatalytic H2 evolution from glycerol solution. The hydrogen production rates are related to the catalyst composition, surface structure, photoabsorption property, as well as the amount of solid solution. The maximum rate of hydrogen production, 550 μmol·h−1 under UV light irradiation and 210 μmol·h−1 under solar-simulated light irradiation, was obtained over Cd0.8Zn0.2S/SiO2 solid solution calcined at 723 K.

Fabrication and Characterization of Cellulose Acetate/Montmorillonite Composite Nanofibers by Electrospinning

Directory of Open Access Journals (Sweden)

Se Wook Kim

2015-01-01

Full Text Available Nanofibers composed of cellulose acetate (CA and montmorillonite (MMT were prepared by electrospinning method. MMT was first dispersed in water and mixed with an acetic acid solution of CA. The viscosity and conductivity of the CA/MMT solutions with different MMT contents were measured to compare with those of the CA solution. The CA/MMT solutions were electrospun to fabricate the CA/MMT composite nanofibers. The morphology, thermal stability, and crystalline and mechanical properties of the composite nanofibers were characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive X-ray spectroscopy (EDX, thermogravimetric analysis (TGA, X-ray diffraction (XRD, and tensile test. The average diameters of the CA/MMT composite nanofibers obtained by electrospinning 18 wt% CA/MMT solutions in a mixed acetic acid/water (75/25, w/w solvent ranged from 150~350 nm. The nanofiber diameter decreased with increasing MMT content. TEM indicated the coexistence of CA nanofibers. The CA/MMT composite nanofibers showed improved tensile strength compared to the CA nanofiber due to the physical protective barriers of the silicate clay layers. MMT could be incorporated into the CA nanofibers resulting in about 400% improvement in tensile strength for the CA sample containing 5 wt% MMT.

Application of thermodynamics to silicate crystalline solutions

Science.gov (United States)

Saxena, S. K.

1972-01-01

A review of thermodynamic relations is presented, describing Guggenheim's regular solution models, the simple mixture, the zeroth approximation, and the quasi-chemical model. The possibilities of retrieving useful thermodynamic quantities from phase equilibrium studies are discussed. Such quantities include the activity-composition relations and the free energy of mixing in crystalline solutions. Theory and results of the study of partitioning of elements in coexisting minerals are briefly reviewed. A thermodynamic study of the intercrystalline and intracrystalline ion exchange relations gives useful information on the thermodynamic behavior of the crystalline solutions involved. Such information is necessary for the solution of most petrogenic problems and for geothermometry. Thermodynamic quantities for tungstates (CaWO4-SrWO4) are calculated.

Synthesis, microstructure and mechanical properties of (Ti1−x,Nbx)2AlC/Al2O3 solid solution composites

International Nuclear Information System (INIS)

Zhu, Jianfeng; Han, Na; Wang, Anning

2012-01-01

(Ti,Nb) 2 AlC/Al 2 O 3 in-situ solid solution composites were successfully synthesized from the elemental powder mixtures of Nb 2 O 5 , Ti, Al and carbon black using hot-press-aided reaction synthesis. The reaction path was investigated by differential scanning calorimetry (DSC) and X-ray diffractometry (XRD), and a possible reaction mechanism was proposed to explain the formation of (Ti,Nb) 2 AlC/Al 2 O 3 composites in which the thermite reaction between Al and Nb 2 O 5 formed Al 2 O 3 and Nb, and the latter together with TiAl and TiC reacted to form (Ti,Nb) 2 AlC. The synthesized composites show plate-like grains packed in a laminated structure typical of Ti 2 AlC, and the fine Al 2 O 3 particles formed in-situ tend to disperse on the matrix grain boundaries. Compared with the monolithic Ti 2 AlC synthesized using an identical process, the Vickers hardness, maximum compressive stress, flexural strength and fracture toughness of (Ti 0.96 ,Nb 0.04 ) 2 AlC/5 wt% Al 2 O 3 were enhanced by 33.8%, 12.1%, 118.4% and 111.8%, respectively. The mechanisms by which Al 2 O 3 increases the strength and toughness of the material were also discussed.

Biosensors Based on Ultrathin Film Composite Membranes

Science.gov (United States)

1994-01-25

composite membranes should have a number C •’ of potential advantages including fast response time, simplicity of construction, and applicability to a number...The support membrane for the ultrathin film composite was an Anopore ( Alltech Associates) microporous alumina filter, these membranes are 55 Pm thick...constant 02 concentration in this solution. Finally, one of the most important potential advantage of a sensor based on an ultrathin film composite

Effect of cyclic loading on microleakage of silorane based composite compared with low shrinkage methacrylate-based composites

Directory of Open Access Journals (Sweden)

Hamid Kermanshah

2016-01-01

Conclusion: Silorane did not provide better marginal seal than the low shrinkage methacrylate-based composites (except Aelite. In addition, cyclic loading did not affect the marginal microleakage of evaluated composite restorations .

Quantifying solute transport processes: are chemically "conservative" tracers electrically conservative?

Science.gov (United States)

Singha, Kamini; Li, Li; Day-Lewis, Frederick D.; Regberg, Aaron B.

2012-01-01

The concept of a nonreactive or conservative tracer, commonly invoked in investigations of solute transport, requires additional study in the context of electrical geophysical monitoring. Tracers that are commonly considered conservative may undergo reactive processes, such as ion exchange, thus changing the aqueous composition of the system. As a result, the measured electrical conductivity may reflect not only solute transport but also reactive processes. We have evaluated the impacts of ion exchange reactions, rate-limited mass transfer, and surface conduction on quantifying tracer mass, mean arrival time, and temporal variance in laboratory-scale column experiments. Numerical examples showed that (1) ion exchange can lead to resistivity-estimated tracer mass, velocity, and dispersivity that may be inaccurate; (2) mass transfer leads to an overestimate in the mobile tracer mass and an underestimate in velocity when using electrical methods; and (3) surface conductance does not notably affect estimated moments when high-concentration tracers are used, although this phenomenon may be important at low concentrations or in sediments with high and/or spatially variable cation-exchange capacity. In all cases, colocated groundwater concentration measurements are of high importance for interpreting geophysical data with respect to the controlling transport processes of interest.

Microporous uranyl chromates successively formed by evaporation from acidic solution

Energy Technology Data Exchange (ETDEWEB)

Siidra, Oleg I.; Nazarchuk, Evgeny V.; Bocharov, Sergey N.; Kayukov, Roman A. [St. Petersburg State Univ. (Russian Federation). Dept. of Crystallography; Depmeier, Wulf [Kiel Univ. (Germany). Inst. fuer Geowissenschaften

2018-04-01

The first microporous framework structures containing uranium and chromium have been synthesized and characterized. Rb{sub 2}[(UO{sub 2}){sub 2}(CrO{sub 4}){sub 3}(H{sub 2}O){sub 2}](H{sub 2}O){sub 3} (1) was crystallized from uranyl chromate solution by evaporation. Further evaporation led to increased viscosity of the solution and overgrowing of Rb{sub 2}[(UO{sub 2}){sub 2}(CrO{sub 4}){sub 3}(H{sub 2}O)](H{sub 2}O) (2) on the crystals of 1. With respect to 1, the framework of 2 is partially dehydrated. Both frameworks differ compositionally by only one water molecule, but this seemingly small difference affects significantly the pore size and overall structural topology of the frameworks, which present very different flexibility of the U-O-Cr links. These are rigid in the pillared framework of 1, in contrast to 2 where the U-O-Cr angles range from 126.3 to 168.2 , reflecting the substantial flexibility of Cr-O-U connections which make them comparable to the corresponding Mo-O-U links in uranyl molybdates.

Repeated application of organic waste affects soil organic matter composition

DEFF Research Database (Denmark)

Peltre, Clément; Gregorich, Edward G.; Bruun, Sander

2017-01-01

Land application of organic waste is an important alternative to landfilling and incineration because it helps restore soil fertility and has environmental and agronomic benefits. These benefits may be related to the biochemical composition of the waste, which can result in the accumulation...... of different types of carbon compounds in soil. The objective of this study was to identify and characterise changes in soil organic matter (SOM) composition after repeated applications of organic waste. Soil from the CRUCIAL field experiment in Denmark was sampled after 12 years of annual application...... that there was accumulation in soil of different C compounds for the different types of applied organic waste, which appeared to be related to the degree to which microbial activity was stimulated and the type of microbial communities applied with the wastes or associated with the decomposition of applied wastes...

Morphological Effects of HA on the Cell Compatibility of Electrospun HA/PLGA Composite Nanofiber Scaffolds

Directory of Open Access Journals (Sweden)

Adnan Haider

2014-01-01

Full Text Available Tissue engineering is faced with an uphill challenge to design a platform with appropriate topography and suitable surface chemistry, which could encourage desired cellular activities and guide bone tissue regeneration. To develop such scaffolds, composite nanofiber scaffolds of nHA and sHA with PLGA were fabricated using electrospinning technique. nHA was synthesized using precipitation method, whereas sHA was purchased. The nHA and sHA were suspended in PLGA solution separately and electrospun at optimized electrospinning parameters. The composite nanofiber scaffolds were characterized by FE-SEM, EDX analysis, TEM, XRD analysis, FTIR, and X-ray photoelectron. The potential of the HA/PLGA composite nanofiber as bone scaffolds in terms of their bioactivity and biocompatibility was assessed by culturing the osteoblastic cells onto the composite nanofiber scaffolds. The results from in vitro studies revealed that the nHA/PLGA composite nanofiber scaffolds showed higher cellular adhesion, proliferation, and enhanced osteogenesis performance, along with increased Ca+2 ions release compared to the sHA/PLGA composite nanofiber scaffolds and pristine PLGA nanofiber scaffold. The results show that the structural dependent property of HA might affect its potential as bone scaffold and implantable materials in regenerative medicine and clinical tissue engineering.

FLEXURAL PROPERTIES OF ALKALINE TREATED SUGAR PALM FIBRE REINFORCED EPOXY COMPOSITES

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D. Bachtiar

2010-06-01

Full Text Available A study of the effect of alkaline treatment on the flexural properties of sugar palm fibre reinforced epoxy composites is presented in this paper. The composites were reinforced with 10% weight fraction of the fibres. The fibres were treated using sodium hydroxide (NaOH with 0.25 M and 0.5 M concentration solution for 1 hour, 4 hours and 8 hours soaking time. The purpose of treating fibres with alkali was to enhance the interfacial bonding between matrix and fibre surfaces. The maximum flexural strength occurred at 0.25 M NaOH solution with 1 hour of soaking time, i.e 96.71 MPa, improving by 24.41% from untreated fibre composite. But, the maximum flexural modulus took place at 0.5 M NaOH solution with 4 hours soaking time, i.e. 6948 MPa, improving by 148% from untreated composite.

Influence of plant root morphology and tissue composition on phenanthrene uptake: Stepwise multiple linear regression analysis

International Nuclear Information System (INIS)

Zhan, Xinhua; Liang, Xiao; Xu, Guohua; Zhou, Lixiang

2013-01-01

Polycyclic aromatic hydrocarbons (PAHs) are contaminants that reside mainly in surface soils. Dietary intake of plant-based foods can make a major contribution to total PAH exposure. Little information is available on the relationship between root morphology and plant uptake of PAHs. An understanding of plant root morphologic and compositional factors that affect root uptake of contaminants is important and can inform both agricultural (chemical contamination of crops) and engineering (phytoremediation) applications. Five crop plant species are grown hydroponically in solutions containing the PAH phenanthrene. Measurements are taken for 1) phenanthrene uptake, 2) root morphology – specific surface area, volume, surface area, tip number and total root length and 3) root tissue composition – water, lipid, protein and carbohydrate content. These factors are compared through Pearson's correlation and multiple linear regression analysis. The major factors which promote phenanthrene uptake are specific surface area and lipid content. -- Highlights: •There is no correlation between phenanthrene uptake and total root length, and water. •Specific surface area and lipid are the most crucial factors for phenanthrene uptake. •The contribution of specific surface area is greater than that of lipid. -- The contribution of specific surface area is greater than that of lipid in the two most important root morphological and compositional factors affecting phenanthrene uptake

Characterization behavior of some polymeric composite ion exchangers

International Nuclear Information System (INIS)

El-Zahhar, A.A; Ahdel-Aziz, H.M.; Siyam, T.

2005-01-01

Polymeric composite resins were prepared by template polymerization process in aqueous solution. Thermogravimetric analysis (TGA), differential thermal analysis (DTA) and The X-ray diffraction patterns (XRD) were performed to evaluate the physico chemical properties of the different polymeric composite resins. The TGA and DTA clarify high thermal stability of prepared polymeric composite resins. XRD of prepared polymeric composite shows that there is crystalline structure of some resins while other are amorphous one

Electrodeposition of white copper-tin alloys from alkaline cyanide solutions

International Nuclear Information System (INIS)

Purwadaria, H.S.; Zainal Arifin Ahmad

2007-01-01

Electrodeposition of white copper-tin alloys (including with mir alloys) has been done onto planar mild steel substrates from alkaline cyanide solutions at 65 degree C. The chemical composition of the coating is influenced by plating bath composition and current density. White mir alloy can be produced from the test solution containing 10 g/l CuCN 2 ,45 g/l Na 2 SnO 3 , 25 g/l NaCN, and 12 g/l NaOH at current density about 5 mA/cm?2. The local compositions of the coating cross section were analyzed using EDX installed in a FESEM operated at an accelerating voltage of 20 kV. The phases formed during co-deposition process were identified using XRD at 25 mA current and 35 kV voltage. (Author)

Reinforcement Learning Based Web Service Compositions for Mobile Business

Science.gov (United States)

Zhou, Juan; Chen, Shouming

In this paper, we propose a new solution to Reactive Web Service Composition, via molding with Reinforcement Learning, and introducing modified (alterable) QoS variables into the model as elements in the Markov Decision Process tuple. Moreover, we give an example of Reactive-WSC-based mobile banking, to demonstrate the intrinsic capability of the solution in question of obtaining the optimized service composition, characterized by (alterable) target QoS variable sets with optimized values. Consequently, we come to the conclusion that the solution has decent potentials in boosting customer experiences and qualities of services in Web Services, and those in applications in the whole electronic commerce and business sector.

Solute redistribution studies in oxidised zirconium alloys

Energy Technology Data Exchange (ETDEWEB)

Khera, S K; Kale, G B; Gadiyar, H S [Bhabha Atomic Research Centre, Bombay (India). Metallurgy Div.

1977-01-01

Electron microprobe studies on solute distribution in oxide layers and in the regions near oxide metal interface have been carried out in the case of zircaloy-2 and zirconium binary alloys containing niobium, tin, iron, copper, chromium and nickel and oxidised in steam at 550 deg C. In the case of alloys having higher oxidation rates, the oxide of solute element was found to dissolve in ZrO/sub 2/ without any composition variation. However, for solute addition with limited solubility like Cr, Cu and Fe, solute enrichment at metal/oxide interface and depletion of the same matrix has been observed. The intensity profiles for nickel distribution were also found to be identical to Fe or Cr distribution. The mode of solute distribution has been discussed in relation to oxidation behaviour of these alloys.

Activity coefficients of solutes in binary solvents

International Nuclear Information System (INIS)

Gokcen, N.A.

1982-01-01

The activity coefficients in dilute ternary systems are discussed in detail by using the Margules equations. Analyses of some relevant data at high temperatures show that the sparingly dissolved solutes in binary solvents follow complex behavior even when the binary solvents are very nearly ideal. It is shown that the activity data on the solute or the binary system cannot permit computation of the remaining activities except for the regular solutions. It is also shown that a fourth-order equation is usually adequate in expressing the activity coefficient of a solute in binary solvents at high temperatures. When the activity data for a binary solvent are difficult to obtain in a certain range of composition, the activity data for a sparingly dissolved solute can be used to supplement determination of the binary activities

A new Class of Extremal Composites

DEFF Research Database (Denmark)

Sigmund, Ole

2000-01-01

microstructure belonging to the new class of composites has maximum bulk modulus and lower shear modulus than any previously known composite. Inspiration for the new composite class comes from a numerical topology design procedure which solves the inverse homogenization problem of distributing two isotropic......The paper presents a new class of two-phase isotropic composites with extremal bulk modulus. The new class consists of micro geometrics for which exact solutions can be proven and their bulk moduli are shown to coincide with the Hashin-Shtrikman bounds. The results hold for two and three dimensions...... and for both well- and non-well-ordered isotropic constituent phases. The new class of composites constitutes an alternative to the three previously known extremal composite classes: finite rank laminates, composite sphere assemblages and Vigdergauz microstructures. An isotropic honeycomb-like hexagonal...

Neighboring trees affect ectomycorrhizal fungal community composition in a woodland-forest ecotone.

Science.gov (United States)

Hubert, Nathaniel A; Gehring, Catherine A

2008-09-01

Ectomycorrhizal fungi (EMF) are frequently species rich and functionally diverse; yet, our knowledge of the environmental factors that influence local EMF diversity and species composition remains poor. In particular, little is known about the influence of neighboring plants on EMF community structure. We tested the hypothesis that the EMF of plants with heterospecific neighbors would differ in species richness and community composition from the EMF of plants with conspecific neighbors. We conducted our study at the ecotone between pinyon (Pinus edulis)-juniper (Juniperus monosperma) woodland and ponderosa pine (Pinus ponderosa) forest in northern Arizona, USA where the dominant trees formed associations with either EMF (P. edulis and P. ponderosa) or arbuscular mycorrhizal fungi (AMF; J. monosperma). We also compared the EMF communities of pinyon and ponderosa pines where their rhizospheres overlapped. The EMF community composition, but not species richness of pinyon pines was significantly influenced by neighboring AM juniper, but not by neighboring EM ponderosa pine. Ponderosa pine EMF communities were different in species composition when growing in association with pinyon pine than when growing in association with a conspecific. The EMF communities of pinyon and ponderosa pines were similar where their rhizospheres overlapped consisting of primarily the same species in similar relative abundance. Our findings suggest that neighboring tree species identity shaped EMF community structure, but that these effects were specific to host-neighbor combinations. The overlap in community composition between pinyon pine and ponderosa pine suggests that these tree species may serve as reservoirs of EMF inoculum for one another.

External nitrogen input affects pre- and post-harvest cell wall composition but not the enzymatic saccharification of wheat straw

DEFF Research Database (Denmark)

Baldwin, Laetitia Andrée; Glazowska, Sylwia Emilia; Mravec, Jozef

2017-01-01

Wheat is one of the most important crops for food and feed and its straw is a potential feedstock for biorefinery purposes. Nitrogen (N) is an essential input factor in wheat agriculture but no information is available on how it affects straw composition during maturation and at harvest....... To investigate this, we conducted a large scale field experiment in which wheat plants were cultivated at three levels of externally applied N. The plants were harvested at different stages of maturation, spanning green straw at heading (ear emergence) to fully yellow straw at final maturity. Defined parts...

Optical Properties and Surface Morphology of Nano-composite PMMA: TiO2 Thin Films

International Nuclear Information System (INIS)

Lyly Nyl Ismail; Ahmad Fairoz Aziz; Habibah Zulkefle

2011-01-01

There are two nano-composite PMMA: TiO 2 solutions were prepared in this research. First solution is nano-composite PMMA commercially available TiO 2 nanopowder and the second solution is nano-composite PMMA with self-prepared TiO 2 powder. The self-prepared TiO 2 powder is obtained by preparing the TiO 2 sol-gel. Solvo thermal method were used to dry the TiO 2 sol-gel and obtained TiO 2 crystal. Ball millers were used to grind the TiO 2 crystal in order to obtained nano sized powder. Triton-X was used as surfactant to stabilizer the composite between PMMA: TiO 2 . Besides comparing the nano-composite solution, we also studied the effect of the thin films thickness on the optical properties and surface morphology of the thin films. The thin films were deposited by sol-gel spin coating method on glass substrates. The optical properties and surface characterization were measured with UV-VIS spectrometer equipment and atomic force microscopy (AFM). The result showed that nano-composite PMMA with self prepared TiO 2 give high optical transparency than nano-composite PMMA with commercially available TiO 2 nano powder. The results also indicate as the thickness is increased the optical transparency are decreased. Both AFM images showed that the agglomerations of TiO 2 particles are occurred on the thin films and the surface roughness is increased when the thickness is increased. High agglomeration particles exist in the AFM images for nano-composite PMMA: TiO 2 with TiO 2 nano powder compare to the other nano-composite solution. (author)

The Effects of Changing Membrane Compositions and Internal Electrolytes on the Respon of Potassium Ion Sensor

OpenAIRE

Ulianas, Alizar; Heng, Lee Yook

2015-01-01

A study on the changing of membrane compositions and internal solution towards the response potassium ion sensor was carried out. Potassium ion sensor based on photocured cross linking poly(n-butyl acrylate) membranes with varying composition of valinomycin (val), sodium tetrakis [3.5-bis(trifluoro-methyl) phenyl] borat (NaTFPB), types ion of internal solution were investigated. Effects of varying composition of val, NaTFPB, types and concentration of internal solution were observed on potass...

Chemistry of fog: Factors regulating its composition

Energy Technology Data Exchange (ETDEWEB)