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Sample records for aluminum silicates

  1. Final report on the safety assessment of aluminum silicate, calcium silicate, magnesium aluminum silicate, magnesium silicate, magnesium trisilicate, sodium magnesium silicate, zirconium silicate, attapulgite, bentonite, Fuller's earth, hectorite, kaolin, lithium magnesium silicate, lithium magnesium sodium silicate, montmorillonite, pyrophyllite, and zeolite.

    Science.gov (United States)

    Elmore, Amy R

    2003-01-01

    This report reviews the safety of Aluminum, Calcium, Lithium Magnesium, Lithium Magnesium Sodium, Magnesium Aluminum, Magnesium, Sodium Magnesium, and Zirconium Silicates, Magnesium Trisilicate, Attapulgite, Bentonite, Fuller's Earth, Hectorite, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite as used in cosmetic formulations. The common aspect of all these claylike ingredients is that they contain silicon, oxygen, and one or more metals. Many silicates occur naturally and are mined; yet others are produced synthetically. Typical cosmetic uses of silicates include abrasive, opacifying agent, viscosity-increasing agent, anticaking agent, emulsion stabilizer, binder, and suspending agent. Clay silicates (silicates containing water in their structure) primarily function as adsorbents, opacifiers, and viscosity-increasing agents. Pyrophyllite is also used as a colorant. The International Agency for Research on Cancer has ruled Attapulgite fibers >5 microm as possibly carcinogenic to humans, but fibers mining and processing of Aluminum Silicate, Calcium Silicate, Zirconium Silicate, Fuller's Earth, Kaolin, Montmorillonite, Pyrophyllite, and Zeolite. The Cosmetic Ingredient Review (CIR. The Cosmetic Ingredient Review (CIR) Expert Panel concluded that the extensive pulmonary damage in humans was the result of direct occupational inhalation of the dusts and noted that lesions seen in animals were affected by particle size, fiber length, and concentration. The Panel considers that most of the formulations are not respirable and of the preparations that are respirable, the concentration of the ingredient is very low. Even so, the Panel considered that any spray containing these solids should be formulated to minimize their inhalation. With this admonition to the cosmetics industry, the CIR Expert Panel concluded that these ingredients are safe as currently used in cosmetic formulations. The Panel did note that the cosmetic ingredient, Talc, is a hydrated magnesium silicate

  2. Total allowable concentrations of monomeric inorganic aluminum and hydrated aluminum silicates in drinking water.

    Science.gov (United States)

    Willhite, Calvin C; Ball, Gwendolyn L; McLellan, Clifton J

    2012-05-01

    Maximum contaminant levels are used to control potential health hazards posed by chemicals in drinking water, but no primary national or international limits for aluminum (Al) have been adopted. Given the differences in toxicological profiles, the present evaluation derives total allowable concentrations for certain water-soluble inorganic Al compounds (including chloride, hydroxide, oxide, phosphate and sulfate) and for the hydrated Al silicates (including attapulgite, bentonite/montmorillonite, illite, kaolinite) in drinking water. The chemistry, toxicology and clinical experience with Al materials are extensive and depend upon the particular physical and chemical form. In general, the water solubility of the monomeric Al materials depends on pH and their water solubility and gastrointestinal bioavailability are much greater than that of the hydrated Al silicates. Other than Al-containing antacids and buffered aspirin, food is the primary source of Al exposure for most healthy people. Systemic uptake of Al after ingestion of the monomeric salts is somewhat greater from drinking water (0.28%) than from food (0.1%). Once absorbed, Al accumulates in bone, brain, liver and kidney, with bone as the major site for Al deposition in humans. Oral Al hydroxide is used routinely to bind phosphate salts in the gut to control hyperphosphatemia in people with compromised renal function. Signs of chronic Al toxicity in the musculoskeletal system include a vitamin D-resistant osteomalacia (deranged membranous bone formation characterized by accumulation of the osteoid matrix and reduced mineralization, reduced numbers of osteoblasts and osteoclasts, decreased lamellar and osteoid bands with elevated Al concentrations) presenting as bone pain and proximal myopathy. Aluminum-induced bone disease can progress to stress fractures of the ribs, femur, vertebrae, humerus and metatarsals. Serum Al ≥100 µg/L has a 75-88% positive predictive value for Al bone disease. Chronic Al

  3. Nicotine-magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    DEFF Research Database (Denmark)

    Kanjanakawinkul, Watchara; Rades, Thomas; Puttipipatkhachorn, Satit

    2013-01-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle...

  4. Characterization of chitosan-magnesium aluminum silicate nanocomposite films for buccal delivery of nicotine

    DEFF Research Database (Denmark)

    Pongjanyakul, Thaned; Khunawattanakul, Wanwisa; Strachan, Clare J

    2013-01-01

    The objective of this study was to prepare and characterize chitosan-magnesium aluminum silicate (CS-MAS) nanocomposite films as a buccal delivery system for nicotine (NCT). The effects of the CS-MAS ratio on the physicochemical properties, release and permeation, as well as on the mucoadhesive...

  5. Study on Properties and Synthesize of a new Polymeric Aluminum Sulfate-silicate

    Institute of Scientific and Technical Information of China (English)

    Yu Shu-rong; Wang Qing-ning; Zhang Fei-long; Ye Qi-zhi

    2004-01-01

    The polymeric basic aluminum silicate-sulfate can be made from three substances, such as aluminum sulfate, sodium silicate and sodium aluminates. Adoption sort neote ric one synthesis,under high shear mixing condition to produce polymeric Aluminum Sulfate-silicate--inorganic macromolecule flocculants, that is liquid, PH is 3.0, molecular formula: AlA (OH) B (SO4) C (SiOx)Because inorganic macromolecule have capability of electricity neutralized, bigger molecular mass,strong capability of adsorption, and products are relative stabilize, more economical than organic macromolecule flocculants, innocuity and high effect compared with tradition flocculants.We can use the flocculants to make sewages purified .The sewages contain sulfur, oiliness, which are treated sewages of oil refining to organism treatment sump in parturition course of oil refining,and the sewages of dark and white in parturition course of paper mill. We study the properties of the flocculants, change of CODCr and effect of sewerage decolouring and so on.Thus fig. Can be seen to add the flocculants(0.1ml) to the sewages of the oil refining and the paper mill that effect is not distinctly. Yet increase of quantity to remove turbidity and floccules effect is distinctness. When the flocculants (0.5mi) be added to the dark sewage of, the penetrate light rate attain 90~98%, the sewage of the oil refining is about 90%, but when we make floccules experiment, the color of dark green and auras of the sewages of oil refining and the paper mill are all disappear, the PASS that add to the sewage will have certainly time to flocculate. When use pay attention to quantity and horary the connection.As a result in the sewages purified, those products form quickly, granule density is big, and subsided velocity is quickly, Floccules effect and capability of removing turbidity, removing CODCr are ascendancy than tradition flocculants - aluminates, and the remained aluminum of water treatment is little. It has

  6. Nicotine–magnesium aluminum silicate microparticle surface modified with chitosan for mucosal delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kanjanakawinkul, Watchara [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand); Rades, Thomas [School of Pharmacy, University of Otago, Dunedin 9054 (New Zealand); Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2100 Copenhagen (Denmark); Puttipipatkhachorn, Satit [Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400 (Thailand); Pongjanyakul, Thaned, E-mail: thaned@kku.ac.th [Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002 (Thailand)

    2013-04-01

    Magnesium aluminum silicate (MAS), a negatively charged clay, and nicotine (NCT), a basic drug, can interact electrostatically to form microparticles. Chitosan (CS) was used for the surface modification of the microparticles, and a lyophilization method was used to preserve the original particle morphology. The microparticles were characterized in terms of their physicochemical properties, NCT content, mucoadhesive properties, and release and permeation across porcine esophageal mucosa. The results showed that the microparticles formed via electrostatic interaction between MAS and protonated NCT had an irregular shape and that their NCT content increased with increasing NCT ratios in the microparticle preparation solution. High molecular weight CS (800 kDa) adsorbed to the microparticle surface and induced a positive surface charge. CS molecules intercalated into the MAS silicate layers and decreased the crystallinity of the microparticles, leading to an increase in the release rate and diffusion coefficient of NCT from the microparticles. Moreover, the microparticle surface modified with CS was found to have higher NCT permeation fluxes and mucoadhesive properties, which indicated the significant role of CS for NCT mucosal delivery. However, the enhancement of NCT permeation and of mucoadhesive properties depended on the molecular weight and concentration of CS. These findings suggest that NCT-MAS microparticle surface modified with CS represents a promising mucosal delivery system for NCT. Highlights: ► Nicotine–magnesium aluminum silicate microparticles were prepared using electrostatic interaction. ► Lyophilization was used for drying and maintaining an original morphology of the microparticles. ► Chitosan (CS) was used for surface modification of the microparticles at acidic pH. ► Surface modification using CS caused an increase in release and permeation of nicotine. ► Microparticle surface-modified with CS presented better mucoadhesive properties.

  7. Effect of aluminum silicate fiber modification on crack-resistance of a ceramic mould

    Directory of Open Access Journals (Sweden)

    Jiang Yehua

    2012-11-01

    Full Text Available To improve the crack-resistance of the mould for silica sol bonded quartz based ceramic mould casting, aluminum silicate fibers with the diameter ranging from 5 µm to 25 µm and the length about 1 mm were dispersed in the ceramic mould. The effect of the aluminum silicate fibers on the tensile strength, shrinkage rate and the cracking trend of the ceramic mould were investigated. In the ceramic slurry, quartz sand was applied as ceramic aggregate, silica sol containing 30% silicon dioxide as bonder, and the weight ratio of quartz sand to silica sol was 2.69; the dispersed fibers changed from 0 to 0.24vol.%. The mould samples were formed after the slurry was poured and gelled at room temperature, and then sintered at different temperatures ranging from 100 to 800 ℃ to measure the tensile strength and shrinkage rate. The results show that, with the aluminum silicate fiber addition increasing from 0 to 0.24vol.%, the tensile strength increases linearly from 0.175 MPa to 0.236 MPa, and the shrinkage rate decreases linearly from 1.75% to 1.68% for the ceramic mould sintered at 400 ℃, from 1.37% to 1.31% for the ceramic mould at room temperature. As the sintering temperature was raised from 100 ℃ to 800 ℃, the tensile strength increases, and the shrinkage rate decreases at all temperatures, compared with those without fiber dispersion, but their variation patterns remain the same. Furthermore, the cracking trend of the mould and its decreasing proportion were defined and analyzed quantitatively considering both effects of the fiber dispersion on the strength and shrinkage. The cracking trend appears to decrease linearly with increasing fiber content and to reach the maximum reduction of 28.8% when 0.24vol.% fiber was dispersed. Therefore, the investigation proposes a new method to improve the crack-resistance of the ceramic mould, i.e., inorganic fiber dispersion into the ceramic mould.

  8. Lysozyme-magnesium aluminum silicate microparticles: Molecular interaction, bioactivity and release studies

    DEFF Research Database (Denmark)

    Kanjanakawinkul, Watchara; Medlicott, Natalie J.; Rades, Thomas;

    2015-01-01

    The objectives of this study were to investigate the adsorption behavior of lysozyme (LSZ) onto magnesium aluminum silicate (MAS) at various pHs and to characterize the LSZ–MAS microparticles obtained from the molecular interaction between LSZ and MAS. The results showed that LSZ could be bound...... onto the MAS layers at different pHs, leading to the formation of LSZ–MAS microparticles. The higher preparation pH permitted greater adsorption affinity but a lower adsorption capacity of LSZ onto MAS. LSZ could interact with MAS via hydrogen bonds and electrostatic forces, resulting in the formation......, the LSZ extracted from microparticles prepared at pH 4 showed an obvious change in the tertiary structure, leading to a decrease in the biological activity of the LSZ released. These findings suggested that LSZ can strongly interact with MAS to form microparticles that may potentially be used as delivery...

  9. Quaternary polymethacrylate-magnesium aluminum silicate films: molecular interactions, mechanical properties and tackiness.

    Science.gov (United States)

    Rongthong, Thitiphorn; Sungthongjeen, Srisagul; Siepmann, Juergen; Pongjanyakul, Thaned

    2013-12-15

    The aim of this study was to investigate the impact of the addition of magnesium aluminum silicate (MAS), a natural clay, on the properties of polymeric films based on quaternary polymethacrylates (QPMs). Two commercially available aqueous QPM dispersions were studied: Eudragit(®) RS 30D and Eudragit(®) RL 30D (the dry copolymers containing 5 and 10% quaternary ammonium groups, respectively). The composite QPM-MAS films were prepared by casting. Importantly, QPM interacted with MAS and formed small flocculates prior to film formation. Continuous films were obtained up to MAS contents of 19% (referred to the QPM dry mass). ATR-FTIR and PXRD revealed that the positively charged quaternary ammonium groups of QPM interacted with negatively charged SiO(-) groups of MAS, creating nanocomposite materials. This interaction led to improved thermal stability of the composite films. The puncture strength and elongation at break of dry systems decreased with increasing MAS content. In contrast, the puncture strength of the wet QPM-MAS films (upon exposure to acidic or neutral media) increased with increasing MAS content. Furthermore, incorporation of MAS into QPM films significantly decreased the latter's tackiness in the dry and wet state. These findings suggest that nanocomposite formation between QPM and MAS in the systems can enhance the strength of wet films and decrease their tackiness. Thus, MAS offers an interesting potential as novel anti-tacking agent for QPM coatings.

  10. Influence of sodium silicate concentration on structural and tribological properties of microarc oxidation coatings on 2017A aluminum alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Polat, Aytekin, E-mail: apolat@nigde.edu.t [Department of Mechanical Engineering, Nigde University, Nigde 51100 (Turkey); Makaraci, Murat [Department of Mechanical Engineering, Kocaeli University, Kocaeli (Turkey); Usta, Metin [Department of Materials Science and Engineering, Gebze Institute of Technology, Kocaeli (Turkey)

    2010-08-20

    In this paper, thick and hard oxide coatings resistant to wear were produced on 2017A-T6 Al alloy by the microarc oxidation (MAO) technique in an alkali electrolyte consisting of different sodium silicate concentrations (0-8 g/l). The coatings were characterized by means of optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and surface profilometry. Microhardness, scratch adhesion and pin-on-disk sliding wear tests were also performed to evaluate the tribological properties of the coatings. The influence of sodium silicate concentration on the structural and tribological properties of the MAO coatings was discussed. Results reveal that increasing sodium silicate concentration from 0 to 8 g/l in the electrolyte caused an increase in the electrolyte conductivity (from 7.71 to 18.1 mS/cm) and a decrease in positive final voltage (from 627 to 590 V) in the MAO process. In response to the increase in sodium silicate concentration, the thickness, surface roughness (R{sub a}) and critical load (L{sub c}) corresponding to adhesive failure of the coatings were increased simultaneously from 74 to 144 {mu}m, and 4.4 to 6.58 {mu}m, and 127.76 to 198.54 N, respectively. At the same time, the phase structure and composition of the coatings also varied by the participation of silicate ions in the reactions and their incorporation into the coating structure. Moreover, it was observed that the coating formed in the low sodium silicate concentration (4 g/l) had higher surface hardness (2020 HV) and improved wear resistance than the one (1800 HV) formed in the high sodium silicate concentration (8 g/l). The coatings produced in three different electrolytic solutions provided an excellent wear resistance and a load carrying capacity compared to the uncoated aluminum alloy.

  11. Alginate-magnesium aluminum silicate composite films: effect of film thickness on physical characteristics and permeability.

    Science.gov (United States)

    Pongjanyakul, Thaned; Puttipipatkhachorn, Satit

    2008-01-04

    The different film thicknesses of the sodium alginate-magnesium aluminum silicate (SA-MAS) microcomposite films were prepared by varying volumes of the composite dispersion for casting. Effect of film thickness on thermal behavior, solid-state crystallinity, mechanical properties, water uptake and erosion, and water vapor and drug permeability of the microcomposite films were investigated. The film thickness caused a small change in thermal behavior of the films when tested using DSC and TGA. The crystallinity of the thin films seemed to increase when compared with the thick films. The thin films gave higher tensile strength than the thick films, whereas % elongation of the films was on the contrary resulted in the lower Young's modulus of the films when the film thickness was increased. This was due to the weaker of the film bulk, suggesting that the microscopic matrix structure of the thick films was looser than that of the thin films. Consequently, water uptake and erosion, water vapor permeation and drug diffusion coefficient of the thick films were higher than those of the thin films. The different types of drug on permeability of the films also showed that a positive charge and large molecule of drug, propranolol HCl, had higher lag time and lower diffusion coefficient that acetaminophen, a non-electrolyte and small molecule. This was because of a higher affinity of positive charge drug on MAS in the films. The findings suggest that the evaporation rate of solvent in different volumes of the composite dispersion used in the preparation method could affect crystallinity and strength of the film surface and film bulk of the microcomposite films. This led to a change in water vapor and drug permeability of the films.

  12. Oxide and proton conductivity in aluminum-doped tricalcium oxy-silicate

    Energy Technology Data Exchange (ETDEWEB)

    Porras-Vazquez, J.M.; De la Torre, A.G.; Losilla, E.R.; Aranda, M.A.G. [Dept. Quimica Inorganica, Cristalografia y Mineralogia, Universidad de Malaga, Campus Teatinos, 29071-Malaga (Spain)

    2007-06-15

    Aluminum doping in tricalcium silicate, Ca{sub 3}(SiO{sub 4})O, has been studied by high-resolution laboratory X-ray powder diffraction and the Rietveld method. Two nominal series have been designed and studied. Oxygen-fixed Ca{sub 3-x/2}Al{sub x/2}(Si{sub 1-x/2}Al{sub x/2}O{sub 4})O series has been prepared as single-phase up to x = 0.03. However, oxygen-variable Ca{sub 3}(Si{sub 1-x}Al{sub x}O{sub 4})O{sub 1-x/2}{open_square}{sub x/2} series has not been stabilized for any composition. The samples show oxide anion conductivity with a small p-type electronic contribution under oxidizing conditions. Typical total conductivities for these solids are 10{sup -} {sup 5}-10{sup -} {sup 4}S cm{sup -} {sup 1} at 1100 K. The oxide ion transference numbers are very high, {proportional_to} 0.98, under reducing conditions, i.e. dry 5%H{sub 2}-N{sub 2}/air gradient. The oxide ion transference numbers are slightly lower, {proportional_to} 0.91 under oxidizing conditions, i.e. dry O{sub 2}/air gradient. These compounds display a very important proton contribution to the overall conductivities under humidified atmospheres. The proton transference number ranges between 0.72 and 0.55 at 873 and 1023 K, respectively. (author)

  13. Barium boron aluminum silicate glass system for solid state optical gas sensors

    Science.gov (United States)

    Da Silva, M. J.; Karczewski, J.; Jasinski, P.; Chrzan, A.; Kalinowski, P.; Szymczewska, D.; Jasinski, G.

    2016-11-01

    Recent increasing demand for new eco-friendly materials and for low cost fabrication process for use in optical sensors field, raise concern about alternative materials for this application. We have designed two glass-ceramics compositions from the quaternary ROAl2O3- SiO2-B2O3(R=Ba) alkali-earth aluminum silicate system, labeled B72 and B69, with high refractive index (>1.6), large values of Abbe number (94.0 and 53.0, respectively), and free of lead and arsenic. We present an analysis and discussion of experimental optical properties, thermal and thermo-chemical stability along with important properties such as transition temperature (Tg), onset of crystallization (Tx) as well transport properties as ionic conductivity behavior in the quaternary glass-ceramic system containing boron for use as optical sensors. Complex Impedance Spectra (Bode Plot) and Potentiodynamic Polarization curves (Tafel plots) measurements were carried out in the temperature range of 600 to 850°C. The most probable conductivity mechanism is a thermally activated process of mobile ions overcoming a potential barrier (EA), according to the Arrhenius regime. Here we report that charge transfer is caused by the flux of electrons, in the region of elevated temperatures (>700°C), and is affected by immiscibility of crystals, nucleation and growth type, that causes phase separation. We found conductivity (σ) values from 10-9 to 10-5 S/cm at temperatures between 700 and 850°C. Our results highlight a need for research on ion mobility in the glassy network above the transition range, and the effect cause by metastable immiscibility in the alkaline-earth glasses are exposed. The two glass compositions B72 and B69 can be tailored by proper use as glassy optical sensor.

  14. Aluminum Silicate Nanotube Coating of Siloxane-Poly(lactic acid-Vaterite Composite Fibermats for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Shuji Yamazaki

    2012-01-01

    Full Text Available In our earlier work, a flexible fibermat consisting of a biodegradable composite with soluble silicate species, which has been reported to enhance bone formation, was prepared successfully using poly(L-lactic acid and siloxane-containing calcium carbonate particles by electrospinning. The fibermat showed enhanced bone formation in an in vivo test. In the present work, to improve the hydrophilicity of skeletal fibers in a fibermat, they were coated with nanotubular aluminum silicate crystals, which have a hydrophilic surface that has excellent affinity to body fluids and a high surface area advantageous for pronounced protein adsorption. The nanotubes were coated easily on the fiber surface using an electrophoretic method. In a conventional contact angle test, a drop of water rapidly penetrated into the nanotube-coated fibermat. The culture test using murine osteoblast-like cells (MC3T3-E1 showed that the cell attachment to the nanotube-coated fibermat at an early stage after seeding was enhanced in comparison with that to the noncoated one. This approach may provide a new method of improving the surface of polymer-based biomaterials.

  15. The Solubilization of Model Alzheimer Tangles: Reversing the β-Sheet Conformation Induced by Aluminum with Silicates

    Science.gov (United States)

    Fasman, Gerald D.; Moore, Cathy D.

    1994-11-01

    Neurofibrillary tangles are one of two lesions found in the brain of Alzheimer disease victims. With synthetic peptide fragments of human neurofilament NF-M17 (Glu-Glu-Lys-Gly-Lys-Ser-Pro-Val-Pro-Lys-Ser-Pro-Val-Glu-Glu-Lys-Gly, phosphorylated and unphosphorylated), CD studies were done to examine the effect of sodium orthosilicate on the conformational state produced by Al3+ on fragments of neuronal proteins. Previous studies had shown a conformational transition from α-helix and random to β-pleated sheet upon addition of Al3+ to both phosphorylated and unphosphorylated peptides. If sufficient quantities of Al3+ are added, the peptide precipitates from solution. The ability to reverse or slow the progression of aggregation was examined. Al3+ binding was reversed with 1-2 molar equivalents of sodium orthosilicate (with respect to Al3+), altering the conformation from β-sheet to random coil and resulting in a CD spectrum similar to that of the initial peptide. The tight binding of the SiO4-_4 with the Al3+ provides the mechanism for this transition. These results provide additional information toward understanding the role of aluminum in the Alzheimer diseased brain and suggest the investigation of the possible use of silicates as a therapeutic agent.

  16. MAS-NMR investigations of the crystallization behaviour of lithium aluminum silicate (LAS) glasses containing P 2O 5 and TiO 2 nucleants

    Science.gov (United States)

    Ananthanarayanan, A.; Kothiyal, G. P.; Montagne, L.; Revel, B.

    2010-06-01

    Lithium aluminum silicate (LAS) glass of composition (mol%) 20.4Li 2O-4.0Al 2O 3-68.6SiO 2-3.0K 2O-2.6B 2O 3-0.5P 2O 5-0.9TiO 2 was prepared by melt quenching. The glass was then nucleated and crystallized based on differential thermal analysis (DTA) data and was characterized by 29Si, 31P, 11B and 27Al MAS-NMR. XRD and 29Si NMR showed that lithium metasilicate (Li 2SiO 3) is the first phase to c form followed by cristobalite (SiO 2) and lithium disilicate (Li 2Si 2O 5). 29Si MAS-NMR revealed a change in the network structure already for the glasses nucleated at 550 °C. Since crystalline Li 3PO 4, as observed by 31P MAS-NMR, forms concurrently with the silicate phases, we conclude that crystalline Li 3PO 4 does not act as a nucleating agent for lithium silicate phases. Moreover, 31P NMR indicates the formation of M-PO 4 ( M=B, Al or Ti) complexes. The presence of BO 3 and BO 4 structural units in all the glass/glass-ceramic samples is revealed through 11B MAS-NMR. B remains in the residual glass and the crystallization of silicate phases causes a reduction in the number of alkali ions available for charge compensation. As a result, the number of trigonally coordinated B (BO 3) increases at the expense of tetrahedrally coordinated B (BO 4). The 27Al MAS-NMR spectra indicate the presence of tetrahedrally coordinated Al species, which are only slightly perturbed by the crystallization.

  17. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-Ae [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Abo-Mosallam, Hany A. [Glass Research Department, National Research Centre, Dokki, Cairo (Egypt); Lee, Hye-Young [Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Kim, Gyu-Ri [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Kim, Hae-Won [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Department of Nanobiomedical Science and BK21 Plus NBM Global Research Center for Regenerative Medicine, Dankook University Graduate School, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of); Lee, Hae-Hyoung, E-mail: haelee@dku.edu [Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330-714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714 (Korea, Republic of)

    2014-09-01

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO{sub 2}-P{sub 2}O{sub 5}-CaO-ZnO-MgO{sub (1-X)}-SrO{sub X}-CaF{sub 2} (X = 0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X = 0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X = 0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues. - Highlights: • We developed multicomponent glass compositions for a novel aluminum-free glass ionomer cement (GIC). • The effects of MgO replacement with SrO in the glasses on the mechanical properties and cell proliferation were evaluated. • Substitution of MgO with SrO at low levels led to improvement of mechanical properties and cell viability of the cements. • Microstructural degradations in the cement matrix of the GICs with strontium at high levels were observed after aging.

  18. Aluminum Silicate Nanotube Modification of Cotton-Like Siloxane-poly(L-lactic acid-vaterite Composites

    Directory of Open Access Journals (Sweden)

    Daiheon Lee

    2013-01-01

    Full Text Available In our earlier work, a cotton-like biodegradable composite, consisting of poly(L-lactic acid with siloxane-containing vaterite, has been prepared by electrospinning. In the present work, the fibers skeleton of the cotton-like composites was modified successfully with imogolite, which is hydrophilic and biocompatible, via a dip process using ethanol diluted solution to improve the cellular initial attachment. Almost no change in the fiber morphology after the surface modification was observed. The surface-modified composite showed the similar calcium and silicate ions releasabilities, for activating the osteoblasts, as an unmodified one. Cell culture tests showed that the initial adhesion of murine osteoblast-like cells on the surface of the fibers was enhanced by surface modification.

  19. Predictive model for Pb(II) adsorption on soil minerals (oxides and low-crystalline aluminum silicate) consistent with spectroscopic evidence

    Science.gov (United States)

    Usiyama, Tomoki; Fukushi, Keisuke

    2016-10-01

    Mobility of Pb(II) in surface condition is governed by adsorption processes on soil minerals such as iron oxides and low-crystalline aluminum silicates. The adsorption effectiveness and the surface complex structures of Pb(II) vary sensitively with solution conditions such as pH, ionic strength, Pb(II) loading, and electrolyte anion type. This study was undertaken to construct a quantitative model for Pb(II) on soil minerals. It can predict the adsorption effectiveness and surface complex structures under any solution conditions using the extended triple layer model (ETLM). The Pb(II) adsorption data for goethite, hydrous ferric oxide (HFO), quartz, and low-crystalline aluminum silicate (LCAS) were analyzed with ETLM to retrieve the surface complexation reactions and these equilibrium constants. The adsorption data on goethite, HFO and quartz were referred from reports of earlier studies. Those data for LCAS were measured under a wide range of pH, ionic strength and Pb(II) loadings in NaNO3 and NaCl solutions. All adsorption data can be reasonably regressed using ETLM with the assumptions of inner sphere bidentate complexation and inner sphere monodentate ternary complexation with electrolyte anions, which are consistent with previously reported spectroscopic evidence. Predictions of surface speciation under widely various solution conditions using ETLM revealed that the inner sphere bidentate complex is the predominant species at neutral to high pH conditions. The inner sphere monodentate ternary complex becomes important at low pH, high surface Pb(II) coverage, and high electrolyte concentrations, of which the behavior is consistent with the spectroscopic observation. Comparisons of the obtained adsorption constants on goethite, HFO and quartz exhibited good linear relations between the reciprocals of dielectric constants of solids and adsorption constants. Those linear relations support predictions of the adsorption constants of all oxides based on Born

  20. Development of a novel aluminum-free glass ionomer cement based on magnesium/strontium-silicate glasses.

    Science.gov (United States)

    Kim, Dong-Ae; Abo-Mosallam, Hany A; Lee, Hye-Young; Kim, Gyu-Ri; Kim, Hae-Won; Lee, Hae-Hyoung

    2014-09-01

    The effects of strontium substitution for magnesium in a novel aluminum-free multicomponent glass composition for glass ionomer cements (GICs) were investigated. A series of glass compositions were prepared based on SiO2-P2O5-CaO-ZnO-MgO(1-X)-SrOX-CaF2 (X=0, 0.25, 0.5 and 0.75). The mechanical properties of GICs prepared were characterized by compressive strength, flexural strength, flexural modules, and microhardness. Cell proliferation was evaluated indirectly by CCK-8 assay using various dilutions of the cement and rat mesenchyme stem cells. Incorporation of strontium instead of magnesium in the glasses has a significant influence on setting time of the cements and the properties. All mechanical properties of the GICs with SrO substitution at X=0.25 were significantly increased, then gradually decreased with further increase of the amount of strontium substitution in the glass. The GIC at X=0.25, also, showed an improved cell viability at low doses of the cement extracts in comparison with other groups or control without extracts. The results of this study demonstrate that the glass compositions with strontium substitution at low levels can be successfully used to prepare aluminum-free glass ionomer cements for repair and regeneration of hard tissues.

  1. 聚硅酸硫酸铝絮凝剂去除生活污水中磷的研究%Study on polynucleate aluminum hydroxyl silicate-sulphate flocculent removing phosphorus in sanitary sewage

    Institute of Scientific and Technical Information of China (English)

    胡文云; 杨春林

    2016-01-01

    以硅酸钠(NaSiO3·9H2O),硫酸铝(Al2(SO4)3·18H2O)和硫酸为原料合成了聚硅酸硫酸铝( PASS )絮凝剂,对PASS通过红外光谱和X射线衍射分析进行表征。考察了PASS对生活污水中磷去除的性能,具体的影响因素有:絮凝剂投加量,絮凝过程水力条件,污水的pH值和温度等。单因素实验结果表明,各因素的最佳取值分别为:投加量为10.0 g/L,污水的pH值为5,污水的加热电压为40 V,絮凝过程的混合转速为150 r/min,混合时间为2 min,絮凝过程的反应转速为100 r/min,反应时间为20 min,絮凝过程的沉降时间为50 min。在单因素影响研究的基础上,设计了四因素三水平的正交实验,结果表明PASS絮凝剂对生活污水中磷去除的性能的最佳组合条件为:投加量为15.0 g/L,pH值为5,混合时间为1min,反应转速为100 r/min;各因素的影响顺序为:pH值>投加量>混合时间>反应转速。%A new process of preparing polynucleate aluminum hydroxyl silicate-sulphate compound ( PASS ) was synthesized by sodium silicate , aluminum sulfate and sulfuric acid in this paper , and it was characterized by IR and XRD.The elimination phosphorus property of PASS for the sewage was investigated , and the concrete influencing factors were the agent amount , pH, temperature and the condition of hydraulic power etc .The results of single fac-tor experiments showed the best condition for each factor:the dose of PASS was 10.0 g/L, the pH was 5, the ad-mixture turn was 150 r/min, the mixing time was 2 minutes, the reacting rotational speed was 100 r/min, the mix-ing time was 20 minutes, the setting time was 50 minutes.On the basis of single factor research , the L9 (34 ) orthog-onal experiment was carried on .The results showed the best condition was that the optimum dose of PASS was 15 . 0 g/L,the optimum pH was 5, the best mixing time was 1minutes,and the optimum

  2. 化学增强铝硅酸盐玻璃扩散性能研究%The Diffusion Performance of Potassium and Sodium in Ion Exchanged Aluminum Silicate Glass

    Institute of Scientific and Technical Information of China (English)

    程金树; 赵薇; 肖子凡

    2012-01-01

    了解碱金属离子在玻璃表面的扩散对生产高强度铝硅酸盐系统离子交换玻璃具有重要意义.通过外加Al,讨论不同Al/Na对碱离子扩散影响.采用EPMA测得玻璃断面K+、Na+分布曲线,根据Boltzmann- Matano计算方法得到K+、Na+的扩散系数,根据Arrhenius公式计算得到K+、Na+的扩散活化能.实验证明,随着Al/Na的增加,K+、Na+扩散深度逐渐增加,互扩散系数逐渐增加,K+、Na+平均活化能逐渐增加.讨论玻璃体内Al/Na比例是研究高强度离子交换玻璃的一个重要方向.%In the production of ion exchanged aluminum silicate system glass, the alkali ion diffusion on the glass surface is an important process which must be considered. In this paper, we discussed the impact of additional Al on the diffusion of alkali ions. The penetration depth profiles of alkali ions were obtained by EPMA methods. The diffusion coefficients of alkali ions were calculated by Boltzmann-Matano equation. And the active energy of alkali ions were gotten by Arrhenius equation. The results showed that the penetration depth, the interdiffusion coefficient and the average active energy increased with the increase of Al/Na ratios. It means the Al/Na ratios have a great effect on the diffusion of alkali i-ons.

  3. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  4. Polymer-Layer Silicate Nanocomposites

    DEFF Research Database (Denmark)

    Potarniche, Catalina-Gabriela

    Nowadays, some of the material challenges arise from a performance point of view as well as from recycling and biodegradability. Concerning these aspects, the development of polymer layered silicate nanocomposites can provide possible solutions. This study investigates how to obtain polymer layered...... silicate nanocomposites and their structure-properties relationship. In the first part of the thesis, thermoplastic layered silicates were obtained by extrusion. Different modification methods were tested to observe the intercalation treatment effect on the silicate-modifier interactions. The silicate...

  5. 硅酸铝/不锈钢丝耐高温防火卷帘布的研制及性能分析%Preparation and performance analysis of high temperature resistant fireproof shutter fabric of aluminum silicate/stainless steel wire

    Institute of Scientific and Technical Information of China (English)

    李利君; 卢国建; 赵敏; 王新钢

    2013-01-01

      分析防火卷帘应用现状,介绍硅酸铝/不锈钢丝耐高温防火卷帘布的织物结构、规格设计以及织造各工序的技术关键,并对织造的硅酸铝/不锈钢丝耐高温防火卷帘布的强力和耐火性能进行测试与分析。结果表明,硅酸铝/不锈钢丝耐高温防火卷帘布的强力远远超过国家标准GB 14102—2005《防火卷帘》要求,耐火极限可达3 h。%The application status of fire resistant shutter was analyzed .Fabric configuration, specification design and key technics of weaving of fire resistant shutter fabric of aluminum silicate /stainless steel wire were also introduced.Furthermore, intensity and fire resistant performance of the fabric were tested and analyzed.It was found that the intensity of the fabric , prepared in this paper, exceeded the require-ment of GB 14102—2005 Fire Resistant Shutter.Fire resistant limitation of the fabric reached 3 h.

  6. Silicic Large Igneous Provinces

    Institute of Scientific and Technical Information of China (English)

    Scott Bryan

    2007-01-01

    @@ Large Igneous Provinces (LIPs) are the end-product of huge additions of magma to the continental crust both at the surface and at depth. Since the first categorisation of LIPs by Coffin & Eldholm (1994), it has been recognised that LIPs are more varied inform, age and character, and this includes the recognition of Silicic LIPs. Silicic LIPs are the largest accumulations of primary volcaniclastic rocks at the Earth's surface with areal extents >0.1 Mkm2 and extrusive and subvolcanic intrusive volumes >0.25 Mkm3. The Late Palaeozoic to Cenozoic Silicic LIP events are the best recognised and are similar in terms of their dimension, crustal setting, volcanic architecture and geochemistry.

  7. Silicates in Alien Asteroids

    Science.gov (United States)

    2009-01-01

    This plot of data from NASA's Spitzer Space Telescopes shows that asteroid dust around a dead 'white dwarf' star contains silicates a common mineral on Earth. The data were taken primarily by Spitzer's infrared spectrograph, an instrument that breaks light apart into its basic constituents. The yellow dots show averaged data from the spectrograph, while the orange triangles show older data from Spitzer's infrared array camera. The white dwarf is called GD 40.

  8. Thermochemistry of Silicates

    Science.gov (United States)

    Costa, Gustavo; Jacobson, Nathan

    2015-01-01

    The thermodynamic properties of vapor and condensed phases of silicates are crucial in many fields of science. These quantities address fundamental questions on the formation, stability, transformation, and physical properties of silicate minerals and silicate coating compositions. Here the thermodynamic activities of silica and other species in solid solution have been measured by the analysis of the corresponding high temperature vapors using Knudsen Effusion Mass Spectrometry (KEMS). In first set of experiments KEMS has been used to examine the volatility sequence of species (Fe, SiO, Mg, O2 and O) present in the vapor phase during heating of fosterite-rich olivine (Fo93Fa7) up to 2400 C and to measure the Fe, SiO and Mg activities in its solid solution. The data of fosterite-rich olivine are essential for thermochemical equilibrium models to predict the atmospheric and surface composition of hot, rocky exoplanets (Lava Planets). In the second set of experiments the measured thermodynamic activities of the silica in Y2O3-SiO2 and Yb2O3-SiO2 systems are used to assess their reactivity and degradation recession as environmental barrier coatings (EBCs) in combustion environments (e.g. non-moveable parts of gas turbine engine).

  9. Aluminum alloy

    Science.gov (United States)

    Blackburn, Linda B. (Inventor); Starke, Edgar A., Jr. (Inventor)

    1989-01-01

    This invention relates to aluminum alloys, particularly to aluminum-copper-lithium alloys containing at least about 0.1 percent by weight of indium as an essential component, which are suitable for applications in aircraft and aerospace vehicles. At least about 0.1 percent by weight of indium is added as an essential component to an alloy which precipitates a T1 phase (Al2CuLi). This addition enhances the nucleation of the precipitate T1 phase, producing a microstructure which provides excellent strength as indicated by Rockwell hardness values and confirmed by standard tensile tests.

  10. Environmental silicate nano-biocomposites

    CERN Document Server

    Pollet, Eric

    2012-01-01

    Environmental Silicate Nano-Biocomposites focuses on nano-biocomposites, which are obtained by the association of silicates such as bioclays with biopolymers. By highlighting recent developments and findings, green and biodegradable nano-composites from both renewable and biodegradable polymers are explored. This includes coverage of potential markets such as packaging, agricultures, leisure and the fast food industry. The knowledge and experience of more than twenty international experts in diverse fields, from chemical and biochemical engineering to applications, is brought together in four different sections covering: Biodegradable polymers and Silicates, Clay/Polyesters Nano-biocomposites, Clay/Agropolymers Nano-biocomposites, and Applications and biodegradation of Nano-biocomposites. By exploring the relationships between the biopolymer structures, the processes, and the final properties Environmental Silicate Nano-Biocomposites explains how to design nano-materials to develop new, valuable, environmenta...

  11. On the Anomalous Silicate Absorption Feature of the Prototypical Seyfert 2 Galaxy NGC 1068

    CERN Document Server

    Koehler, Melanie

    2012-01-01

    The first detection of the silicate absorption feature in AGNs was made at 9.7 micrometer for the prototypical Seyfert 2 galaxy NGC 1068 over 30 years ago, indicating the presence of a large column of silicate dust in the line-of-sight to the nucleus. It is now well recognized that type 2 AGNs exhibit prominent silicate absorption bands, while the silicate bands of type 1 AGNs appear in emission. More recently, using the Mid-Infrared Interferometric Instrument on the Very Large Telescope Interferometer, Jaffe et al. (2004) by the first time spatially resolved the parsec-sized dust torus around NGC 1068 and found that the 10 micrometer silicate absorption feature of the innermost hot component exhibits an anomalous profile differing from that of the interstellar medium and that of common olivine-type silicate dust. While they ascribed the anomalous absorption profile to gehlenite (Ca_2Al_2SiO_7, a calcium aluminum silicate species), we propose a physical dust model and argue that, although the presence of gehl...

  12. Stardust silicates from primitive meteorites.

    Science.gov (United States)

    Nagashima, Kazuhide; Krot, Alexander N; Yurimoto, Hisayoshi

    2004-04-29

    Primitive chondritic meteorites contain material (presolar grains), at the level of a few parts per million, that predates the formation of our Solar System. Astronomical observations and the chemical composition of the Sun both suggest that silicates must have been the dominant solids in the protoplanetary disk from which the planets of the Solar System formed, but no presolar silicates have been identified in chondrites. Here we report the in situ discovery of presolar silicate grains 0.1-1 microm in size in the matrices of two primitive carbonaceous chondrites. These grains are highly enriched in 17O (delta17O(SMOW) > 100-400 per thousand ), but have solar silicon isotopic compositions within analytical uncertainties, suggesting an origin in an oxygen-rich red giant or an asymptotic giant branch star. The estimated abundance of these presolar silicates (3-30 parts per million) is higher than reported for other types of presolar grains in meteorites, consistent with their ubiquity in the early Solar System, but is about two orders of magnitude lower than their abundance in anhydrous interplanetary dust particles. This result is best explained by the destruction of silicates during high-temperature processing in the solar nebula.

  13. NON-AUTOCLAVE SILICATE BRICK

    Directory of Open Access Journals (Sweden)

    V. N. Yaglov

    2015-01-01

    Full Text Available The paper proposes a technology for obtaining bricks on the basis of lime-silica mixtures where chemical interactions are practically completely realized in dispersive state at the stage of preparation of binding contact maturing and raw mixture as a whole. The role of forming operation (moulding is changed in principle because in this case conversion of dispersive system into a rock-like solid occurs and due to this the solid obtains complete water-resistance in contact with water immediately after forming operation. Theoretical basis for the developed technology is capability of silicate dispersive substances (hydrated calcium silicate to transit in non-stable state, to form a rock-like water-resistant solid in the moment of mechanical load application during forming process. Specific feature of the proposed method is an exclusion of additional operations for autoclaving of products from the process of obtaining a silicate brick.Synthetic hydrated calcium silicate in contrast to natural ones are more uniform in composition and structure, they contain less impurities and they are characterized by dispersive composition and due to the mentioned advantages they find wider practical application. Contact-condensation binders permit to manipulate product properties on their basis and ensure maximum correspondence to the requirements of the concrete application. Raw material sources for obtaining synthetic hydrated calcium silicates are practically un-limited because calcium-silicon containing substances are found as in various technogenic wastes so in natural compounds as well. So the problem for obtaining hydrated calcium silicates having contact-condensation ability for structure formation becomes more and more actual one. This transition is considered as dependent principally on arrangement rate of substance particles which determined the level of its instability.

  14. 21 CFR 872.6670 - Silicate protector.

    Science.gov (United States)

    2010-04-01

    ... DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6670 Silicate protector. (a) Identification. A silicate protector is a device made of silicone intended to be applied with an absorbent tipped applicator to...

  15. Antibacterial Activity of Silicate Bioceramics

    Institute of Scientific and Technical Information of China (English)

    HU Sheng; NING Congqin; ZHOU Yue; CHEN Lei; LIN Kaili; CHANG Jiang

    2011-01-01

    Four kinds of pure silicate ceramic particles, CaSiO3, Ca3SiO5, bredigite and akermanite were prepared and their bactericidal effects were systematically investigated. The phase compositions of these silicate ceramics were characterized by XRD. The ionic concentration meas urement revealed that the Calcium (Ca) ion concentration were relatively higher in Ca3SiO5 and bredigite, and much lower in CaSiO3 and akermanite. Accordingly, the pH values of the four silicate ceramics extracts showed a positive correlation with the particle concentrations. Meanwhile, by decreasing the particle size, higher Ca ion concentrations can be achieved, leading to the increase of aqueous pH value as well. In summary, all of the four silicate ceramics tested in our study showed antibacterial effect in a dose-dependent manner. Generally, the order of their antibacterial activity against E.coli from strong to weak is Ca3SiO5, bredigite, CaSiO3 and akermanite.

  16. Amended Silicated for Mercury Control

    Energy Technology Data Exchange (ETDEWEB)

    James Butz; Thomas Broderick; Craig Turchi

    2006-12-31

    Amended Silicates{trademark}, a powdered, noncarbon mercury-control sorbent, was tested at Duke Energy's Miami Fort Station, Unit 6 during the first quarter of 2006. Unit 6 is a 175-MW boiler with a cold-side electrostatic precipitator (ESP). The plant burns run-of-the-river eastern bituminous coal with typical ash contents ranging from 8-15% and sulfur contents from 1.6-2.6% on an as-received basis. The performance of the Amended Silicates sorbent was compared with that for powdered activated carbon (PAC). The trial began with a period of baseline monitoring during which no sorbent was injected. Sampling during this and subsequent periods indicated mercury capture by the native fly ash was less than 10%. After the baseline period, Amended Silicates sorbent was injected at several different ratios, followed by a 30-day trial at a fixed injection ratio of 5-6 lb/MMACF. After this period, PAC was injected to provide a comparison. Approximately 40% mercury control was achieved for both the Amended Silicates sorbent and PAC at injection ratios of 5-6 lbs/MMACF. Higher injection ratios did not achieve significantly increased removal. Similar removal efficiencies have been reported for PAC injection trials at other plants with cold-side ESPs, most notably for plants using medium to high sulfur coal. Sorbent injection did not detrimentally impact plant operations and testing confirmed that the use of Amended Silicates sorbent does not degrade fly ash quality (unlike PAC). The cost for mercury control using either PAC or Amended Silicates sorbent was estimated to be equivalent if fly ash sales are not a consideration. However, if the plant did sell fly ash, the effective cost for mercury control could more than double if those sales were no longer possible, due to lost by-product sales and additional cost for waste disposal. Accordingly, the use of Amended Silicates sorbent could reduce the overall cost of mercury control by 50% or more versus PAC for locations where

  17. INORGANIC PHOSPHORS IN GLASS BASED ON LEAD SILICATE GLASSES

    Directory of Open Access Journals (Sweden)

    V. A. Aseev

    2014-09-01

    Full Text Available We created and synthesized luminescent composite of the "phosphor in glass" type, based on the lead-silicate matrix and fine-dispersed powder of cerium-activated yttrium-aluminum garnet crystal. Lead-silicate system (40SiO2- 20PbO-(40-x PbF2-xAlF3, x = 0-25 was chosen as the glassy matrix. Initial glass was reduced to powder (frit for "phosphor in glass" composite with a particle size about 50 µm. Glass frit and powder of commercial YAG:Ce3+ phosphor were mixed in a ratio of 30 to 70 (wt %. Then this composite was pressed in a tablet and sintered on a quartz substrate at 823 К for 30 minutes. Thus, the plane parallel sheet for composite of the "phosphor in glass" was obtained with a diameter equal to 10 mm. For the purpose to reduce the loss of light in the presence of dispersion at a glass-phosphor boundary, optimization of glass mixture was done by adjusting the refractive index. X-ray phase and spectral-luminescent analysis of the derived composite were done. The results of these studies showed that there was no degradation of YAG: Ce powder during sintering. Dependence of luminescence intensity from temperature in the range from room temperature to 473 К was studied. It was shown, that with the phosphor in glass usage thermal quenching of luminescence was reduced in comparison with the silicone. The model of white LED was created with the "phosphor in glass" composite based on lead-silicate glasses with low temperature of vitrifying. The derived LED emits white light with a color temperature of 4370 K, and the luminous efficiency is equal to 58 lm/W. The developed luminescent composite based on the lead-silicate matrix can be used for the production of high-power white light LED.

  18. Effects of ionization on silicate glasses. [Silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Primak, W.

    1982-02-01

    This evaluation of radiation effects in silicate glasses caused by ionization is based on our own investigations, on material collected in our files (reports, articles, and notes), and on a computer literature search through recent issues of Physics Abstracts and Chemical Abstracts (and the apparently pertinent references which appeared). Some of our recent results, available heretofore only in internal correspondence, are presented in some detail. It is concluded that research into the behavior of silicate glasses generally will be required before the specific effects in the radioactive waste storage glasses can be properly understood and evaluated. Two particular neglected areas of investigation are targeted for immediate concern: a kinetic analysis of annealing data and the acquisition of data on effects of irradiation at controlled elevated temperatures.

  19. Silicate Composition of the Interstellar Medium

    CERN Document Server

    Fogerty, Shane; Watson, Dan M; Sargent, Benjamin A; Koch, Ingrid

    2016-01-01

    The composition of silicate dust in the diffuse interstellar medium and in protoplanetary disks around young stars informs our understanding of the processing and evolution of the dust grains leading up to planet formation. Analysis of the well-known 9.7{\\mu}m feature indicates that small amorphous silicate grains represent a significant fraction of interstellar dust and are also major components of protoplanetary disks. However, this feature is typically modelled assuming amorphous silicate dust of olivine and pyroxene stoichiometries. Here, we analyze interstellar dust with models of silicate dust that include non-stoichiometric amorphous silicate grains. Modelling the optical depth along lines of sight toward the extinguished objects Cyg OB2 No. 12 and {\\zeta} Ophiuchi, we find evidence for interstellar amorphous silicate dust with stoichiometry intermediate between olivine and pyroxene, which we simply refer to as "polivene." Finally, we compare these results to models of silicate emission from the Trapez...

  20. Hydrothermal Synthesis of Metal Silicates

    Institute of Scientific and Technical Information of China (English)

    Lii Kwang-Hwa

    2004-01-01

    Organically templated metal phosphates have been extensively studied because of interesting structural chemistry and potential applications in catalysis. However, in most cases the organic templates cannot be removed without collapse of the frameworks. This is in contrast to the high thermal stability and extensive applications of zeolites in refinery and petrochemical processes.Therefore, studies have been directed to the synthesis of transition metal silicates to produce more stable frameworks. Our synthetic methods are twofold, namely mild hydrothermal reactions in Teflon-lined autoclaves at 100-200 ℃ using organic amines as templates and high-temperature,high-pressure hydrothermal reactions in gold ampoules contained in a high-pressure reaction vessel at ca. 550 ℃ and 150 Mpa using alkali metal cations as templates. In this presentation I will report the high-temperature, high-pressure hydrothermal synthesis, crystal structures, and solid-state NMR spectroscopy of a number of new silicates of indium, uranium, and transition metals.

  1. Surface characterization of silicate bioceramics.

    Science.gov (United States)

    Cerruti, Marta

    2012-03-28

    The success of an implanted prosthetic material is determined by the early events occurring at the interface between the material and the body. These events depend on many surface properties, with the main ones including the surface's composition, porosity, roughness, topography, charge, functional groups and exposed area. This review will portray how our understanding of the surface reactivity of silicate bioceramics has emerged and evolved in the past four decades, owing to the adoption of many complementary surface characterization tools. The review is organized in sections dedicated to a specific surface property, each describing how the property influences the body's response to the material, and the tools that have been adopted to analyse it. The final section introduces the techniques that have yet to be applied extensively to silicate bioceramics, and the information that they could provide.

  2. Biogenic silicate accumulation in sediments, Jiaozhou Bay

    Institute of Scientific and Technical Information of China (English)

    LI Xuegang; SONG Jinming; DAI Jicui; YUAN Huamao; LI Ning; LI Fengye; SUN Song

    2006-01-01

    It has been widely recognized that low silicate content in seawater is a major limiting factor to phytoplankton primary production in Jiaozhou Bay. However the reason of Si-limitation remains poorly understood. In the present study we measured the biogenic silicate content and discussed the accumulation of silicate in Jiaozhou Bay sediment. The results show that the biogenic silica content in the sediment of the Jiaozhou Bay is obviously much higher than those in the Yellow Sea and the Bohai Sea. The BSi:TN ratios and BSi:16P ratios in the sediment are > 1 and the OC:BSi ratio in sediment is lower than these of Redfield ratio (106:16), indicating that the decomposition rate of OC is much higher than that for BSi in similar conditions. Therefore, the majority of the biogenic silicate was buried and thus did not participate in silicate recycling. Silicate accumulation in sediment may explain why Si limits the phytoplankton growth in the Jiaozhou Bay. Comparing the flux of biogenic silicate from sediments with primary production rate, it can be concluded that only 15.5% of biogenic silicate is hydrolyzed during the journey from surface to bottom in seawater, thus approximate 84.5% of biogenic silicate could reach the bottom. The silicate releasing rate from the sediment to seawater is considerably lower than that of sedimentation of biogenic silicate, indicating silicate accumulation in sediment too. In a word, the silicate accumulation in sediment is the key reason of silicate limiting to phytoplankton growth in Jiaozhou Bay.

  3. ALUMINUM BOX BUNDLING PRESS

    Directory of Open Access Journals (Sweden)

    Iosif DUMITRESCU

    2015-05-01

    Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

  4. Cumulate Fragments in Silicic Ignimbrites

    Science.gov (United States)

    Bachmann, O.; Ellis, B. S.; Wolff, J.

    2014-12-01

    Increasingly, studies are concluding that silicic ignimbrites are the result of the amalgamation of multiple discrete magma batches. Yet the existence of discrete batches presents a conundrum for magma generation and storage; if silicic magma batches are not generated nearly in situ in the upper crust, they must traverse, and reside within, a thermally hostile environment with large temperature gradients, resulting in low survivability in their shallow magmatic hearths. The Snake River Plain (Idaho, USA) is a type example of this 'multi-batch' assembly with ignimbrites containing multiple populations of pyroxene crystals, glass shards, and crystal aggregates. The ubiquitous crystal aggregates hint at a mechanism to facilitate the existence of multiple, relatively small batches of rhyolite in the upper crust. These aggregates contain the same plagioclase, pyroxene, and oxide mineral compositions as single phenocrysts of the same minerals in their host rocks, but they have significantly less silicic bulk compositions and lack quartz and sanidine, which occur as single phenocrysts in the deposits. This implies significant crystallization followed by melt extraction from mushy reservoir margins. The extracted melt then continues to evolve (crystallizing sanidine and quartz) while the melt-depleted margins provide an increasingly rigid and refractory network segregating the crystal-poor batches of magma. The hot, refractory, margins insulate the crystal-poor lenses, allowing (1) extended residence in the upper crust, and (2) preservation of chemical heterogeneities among batches. In contrast, systems that produce cumulates richer in low-temperature phases (quartz, K-feldspars, and/or biotite) favour remelting upon recharge, leading to less segregation of eruptible melt pockets and the formation of gradationally zoned ignimbrites. The occurrence of similar crystal aggregates from a variety of magmatic lineages suggests the generality of this process.

  5. Silicate condensation in Mira variables

    CERN Document Server

    Gail, Hans-Peter; Pucci, Annemarie

    2016-01-01

    We study whether the condensation of silicate dust in Mira envelopes could be caused by cluster formation by the abundant SiO molecules. For a simplified model of the pulsational motions of matter in the the outer layers of a Mira variable which is guided by a numerical model for Mira pulsations, the equations of dust nucleation and growth are solved in the co-moving frame of a fixed mass element. It is assumed that seed particles form by clustering of SiO molecules. The calculation of the nucleation rate is based on the experimental data of Nuth and Donn (1982). The quantity of dust formed is calculated by a moment method and the calculation of radiation pressure on the dusty gas is based on a dirty silicate model. Dust nucleation occurs in the model at the upper culmination of the trajectory of a gas parcel where it stays for a considerable time at low temperatures while subsequent dust growth occurs during the descending part of the motion and continues after the next shock reversed motion. It is found tha...

  6. Aspects of aluminum toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Hewitt, C.D.; Savory, J.; Wills, M.R. (Univ. of Virginia Health Sciences Center, Charlottesville (USA))

    1990-06-01

    Aluminum is the most abundant metal in the earth's crust. The widespread occurrence of aluminum, both in the environment and in foodstuffs, makes it virtually impossible for man to avoid exposure to this metal ion. Attention was first drawn to the potential role of aluminum as a toxic metal over 50 years ago, but was dismissed as a toxic agent as recently as 15 years ago. The accumulation of aluminum, in some patients with chronic renal failure, is associated with the development of toxic phenomena; dialysis encephalopathy, osteomalacic dialysis osteodystrophy, and an anemia. Aluminum accumulation also occurs in patients who are not on dialysis, predominantly infants and children with immature or impaired renal function. Aluminum has also been implicated as a toxic agent in the etiology of Alzheimer's disease, Guamiam amyotrophic lateral sclerosis, and parkinsonism-dementia. 119 references.

  7. Aluminum powder metallurgy processing

    Energy Technology Data Exchange (ETDEWEB)

    Flumerfelt, J.F.

    1999-02-12

    The objective of this dissertation is to explore the hypothesis that there is a strong linkage between gas atomization processing conditions, as-atomized aluminum powder characteristics, and the consolidation methodology required to make components from aluminum powder. The hypothesis was tested with pure aluminum powders produced by commercial air atomization, commercial inert gas atomization, and gas atomization reaction synthesis (GARS). A comparison of the GARS aluminum powders with the commercial aluminum powders showed the former to exhibit superior powder characteristics. The powders were compared in terms of size and shape, bulk chemistry, surface oxide chemistry and structure, and oxide film thickness. Minimum explosive concentration measurements assessed the dependence of explosibility hazard on surface area, oxide film thickness, and gas atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization processing conditions. The GARS aluminum powders were exposed to different relative humidity levels, demonstrating the effect of atmospheric conditions on post-atomization oxidation of aluminum powder. An Al-Ti-Y GARS alloy exposed in ambient air at different temperatures revealed the effect of reactive alloy elements on post-atomization powder oxidation. The pure aluminum powders were consolidated by two different routes, a conventional consolidation process for fabricating aerospace components with aluminum powder and a proposed alternative. The consolidation procedures were compared by evaluating the consolidated microstructures and the corresponding mechanical properties. A low temperature solid state sintering experiment demonstrated that tap densified GARS aluminum powders can form sintering necks between contacting powder particles, unlike the total resistance to sintering of commercial air atomization aluminum powder.

  8. Silicates materials of high vacuum technology

    CERN Document Server

    Espe, Werner

    2013-01-01

    Materials of High Vacuum Technology, Volume 2: Silicates covers silicate insulators of special importance to vacuum technology. The book discusses the manufacture, composition, and physical and chemical properties of technical glasses, quartz glass, quartzware, vycor glass, ceramic materials, mica, and asbestos.

  9. Mesoporous Silicate Materials in Sensing

    Directory of Open Access Journals (Sweden)

    Paul T. Charles

    2008-08-01

    Full Text Available Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through cocondensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules.

  10. Is the Aluminum Hypothesis Dead?

    OpenAIRE

    Lidsky, Theodore I.

    2014-01-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed w...

  11. High energy density aluminum battery

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Gilbert M.; Paranthaman, Mariappan Parans; Dai, Sheng; Dudney, Nancy J.; Manthiram, Arumugan; McIntyre, Timothy J.; Sun, Xiao-Guang; Liu, Hansan

    2016-10-11

    Compositions and methods of making are provided for a high energy density aluminum battery. The battery comprises an anode comprising aluminum metal. The battery further comprises a cathode comprising a material capable of intercalating aluminum or lithium ions during a discharge cycle and deintercalating the aluminum or lithium ions during a charge cycle. The battery further comprises an electrolyte capable of supporting reversible deposition and stripping of aluminum at the anode, and reversible intercalation and deintercalation of aluminum or lithium at the cathode.

  12. Is the Aluminum Hypothesis dead?

    Science.gov (United States)

    Lidsky, Theodore I

    2014-05-01

    The Aluminum Hypothesis, the idea that aluminum exposure is involved in the etiology of Alzheimer disease, dates back to a 1965 demonstration that aluminum causes neurofibrillary tangles in the brains of rabbits. Initially the focus of intensive research, the Aluminum Hypothesis has gradually been abandoned by most researchers. Yet, despite this current indifference, the Aluminum Hypothesis continues to attract the attention of a small group of scientists and aluminum continues to be viewed with concern by some of the public. This review article discusses reasons that mainstream science has largely abandoned the Aluminum Hypothesis and explores a possible reason for some in the general public continuing to view aluminum with mistrust.

  13. Anodizing Aluminum with Frills.

    Science.gov (United States)

    Doeltz, Anne E.; And Others

    1983-01-01

    "Anodizing Aluminum" (previously reported in this journal) describes a vivid/relevant laboratory experience for general chemistry students explaining the anodizing of aluminum in sulfuric acid and constrasting it to electroplating. Additions to this procedure and the experiment in which they are used are discussed. Reactions involved are…

  14. The aluminum smelting process.

    Science.gov (United States)

    Kvande, Halvor

    2014-05-01

    This introduction to the industrial primary aluminum production process presents a short description of the electrolytic reduction technology, the history of aluminum, and the importance of this metal and its production process to modern society. Aluminum's special qualities have enabled advances in technologies coupled with energy and cost savings. Aircraft capabilities have been greatly enhanced, and increases in size and capacity are made possible by advances in aluminum technology. The metal's flexibility for shaping and extruding has led to architectural advances in energy-saving building construction. The high strength-to-weight ratio has meant a substantial reduction in energy consumption for trucks and other vehicles. The aluminum industry is therefore a pivotal one for ecological sustainability and strategic for technological development.

  15. Clinical biochemistry of aluminum

    Energy Technology Data Exchange (ETDEWEB)

    King, S.W.; Savory, J.; Wills, M.R.

    1981-05-01

    Aluminum toxicity has been implicated in the pathogenesis of a number of clinical disorders in patients with chronic renal failure on long-term intermittent hemodialysis treatment. The predominant disorders have been those involving either bone (osteomalacic dialysis osteodystrophy) or brain (dialysis encephalopathy). In nonuremic patients, an increased brain aluminum concentration has been implicated as a neurotoxic agent in the pathogenesis of Alzheimer's disease and was associated with experimental neurofibrillary degeneration in animals. The brain aluminum concentrations of patients dying with the syndrome of dialysis encephalopathy (dialysis dementia) are significantly higher than in dialyzed patients without the syndrome and in nondialyzed patients. Two potential sources for the increased tissue content of aluminum in patients on hemodialysis have been proposed: (1) intestinal absorption from aluminum containing phosphate-binding gels, and (2) transfer across the dialysis membrane from aluminum in the water used to prepare the dialysate. These findings, coupled with our everyday exposure to the ubiquitous occurrence of aluminum in nature, have created concerns over the potential toxicity of this metal.

  16. Advances in aluminum pretreatment

    Energy Technology Data Exchange (ETDEWEB)

    Sudour, Michel; Maintier, Philippe [PPG Industries France, 3 Z.A.E. Les Dix Muids, B.P. 89, F-59583 Marly (France); Simpson, Mark [PPG Industries Inc., 1200 Piedmont Troy, Michigan 48083 (United States); Quaglia, Paolo [PPG Industries Italia, Via Garavelli 21, I-15028 Quattordio (Italy)

    2004-07-01

    As automotive manufacturers continue to look for ways to reduce vehicle weight, aluminum is finding more utility as a body panel component. The substitution of cold-rolled steel and zinc-coated substrates with aluminum has led to new challenges in vehicle pretreatment. As a result, changes to traditional pretreatment chemistries and operating practices are necessary in order to produce an acceptable coating on aluminum body panels. These changes result in increased sludging and other undesirable characteristics. In addition to the chemistry changes, there are also process-related problems to consider. Many existing automotive pretreatment lines simply were not designed to handle aluminum and its increased demands on filtration and circulation equipment. To retrofit such a system is capital intensive and in addition to requiring a significant amount of downtime, may not be totally effective. Thus, the complexities of pre-treating aluminum body panels have actually had a negative effect on efforts to introduce more aluminum into new vehicle design programs. Recent research into ways of reducing the negative effects has led to a new understanding of the nature of zinc phosphate bath -aluminum interactions. Many of the issues associated with the pretreatment of aluminum have been identified and can be mitigated with only minor changes to the zinc phosphate bath chemistry. The use of low levels of soluble Fe ions, together with free fluoride, has been shown to dramatically improve the efficiency of a zinc phosphate system processing aluminum. Appearance of zinc phosphate coatings, coating weights and sludge are all benefited by this chemistry change. (authors)

  17. Carbon Monoxide Silicate Reduction System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbon Monoxide Silicate Reduction System (COSRS) is an innovative method that for the first time uses the strong reductant carbon monoxide to both reduce iron...

  18. Carbon Monoxide Silicate Reduction System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Carbon Monoxide Silicate Reduction System (COSRS) is a novel technology for producing large quantities of oxygen on the Moon. Oxygen yields of 15 kilograms per...

  19. Thermodynamics and Kinetics of Silicate Vaporization

    Science.gov (United States)

    Jacobson, Nathan S.; Costa, Gustavo C. C.

    2015-01-01

    Silicates are a common class of materials that are often exposed to high temperatures. The behavior of these materials needs to be understood for applications as high temperature coatings in material science as well as the constituents of lava for geological considerations. The vaporization behavior of these materials is an important aspect of their high temperature behavior and it also provides fundamental thermodynamic data. The application of Knudsen effusion mass spectrometry (KEMS) to silicates is discussed. There are several special considerations for silicates. The first is selection of an appropriate cell material, which is either nearly inert or has well-understood interactions with the silicate. The second consideration is proper measurement of the low vapor pressures. This can be circumvented by using a reducing agent to boost the vapor pressure without changing the solid composition or by working at very high temperatures. The third consideration deals with kinetic barriers to vaporization. The measurement of these barriers, as encompassed in a vaporization coefficient, is discussed. Current measured data of rare earth silicates for high temperature coating applications are discussed. In addition, data on magnesium-iron-silicates (olivine) are presented and discussed.

  20. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  1. Advances in aluminum anodizing

    Science.gov (United States)

    Dale, K. H.

    1969-01-01

    White anodize is applied to aluminum alloy surfaces by specific surface preparation, anodizing, pigmentation, and sealing techniques. The development techniques resulted in alloys, which are used in space vehicles, with good reflectance values and excellent corrosive resistance.

  2. CORROSION PROTECTION OF ALUMINUM

    Science.gov (United States)

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  3. Characterization and nutrient release from silicate rocks and influence on chemical changes in soil

    Directory of Open Access Journals (Sweden)

    Douglas Ramos Guelfi Silva

    2012-06-01

    Full Text Available The expansion of Brazilian agriculture has led to a heavy dependence on imported fertilizers to ensure the supply of the growing food demand. This fact has contributed to a growing interest in alternative nutrient sources, such as ground silicate rocks. It is necessary, however, to know the potential of nutrient release and changes these materials can cause in soils. The purpose of this study was to characterize six silicate rocks and evaluate their effects on the chemical properties of treated soil, assessed by chemical extractants after greenhouse incubation. The experimental design consisted of completely randomized plots, in a 3 x 6 factorial scheme, with four replications. The factors were potassium levels (0-control: without silicate rock application; 200; 400; 600 kg ha-1 of K2O, supplied as six silicate rock types (breccia, biotite schist, ultramafic rock, phlogopite schist and two types of mining waste. The chemical, physical and mineralogical properties of the alternative rock fertilizers were characterized. Treatments were applied to a dystrophic Red-Yellow Oxisol (Ferralsol, which was incubated for 100 days, at 70 % (w/w moisture in 3.7 kg/pots. The soil was evaluated for pH; calcium and magnesium were extracted with KCl 1 mol L-1; potassium, phosphorus and sodium by Mehlich 1; nickel, copper and zinc with DTPA; and the saturation of the cation exchange capacity was calculated for aluminum, calcium, magnesium, potassium, and sodium, and overall base saturation. The alternative fertilizers affected soil chemical properties. Ultramafic rock and Chapada mining byproduct (CMB were the silicate rocks that most influenced soil pH, while the mining byproduct (MB led to high K levels. Zinc availability was highest in the treatments with mining byproduct and Cu in soil fertilized with Chapada and mining byproduct.

  4. Comparison of Conventional and Microwave-assisted Synthesis and Characteristics of Aluminum-pillared Rectorite

    Institute of Scientific and Technical Information of China (English)

    DU Dongyun; ZHAO Xiaorong; LU Xiaohua

    2005-01-01

    The synthesis and characterization of aluminum-pillared rectorite were studied. The synthesis was conducted with both conventional heating and microwave irradiation. Microwave irradiation was found to enhance the intercalation and ion-exchange during synthesis, and to be able to produce the rectorite with a larger d001 and a better uniformity. The specific surface area is 180 m2/g and basal spacing is 3.2 nm. The texture change and thermal and hydrothermal stability of cross-linked rectorite were examined using XRD, FTIR, nitrogen-adsorption and TGA. The experimental results show that the aluminum-pillared rectorite, after calcined at 800 ℃ for 3 hours, can keep the basal aluminum-silicate texture and would not disperse in water at room or an elevated temperature. The aluminum-pillared rectorite shows a high specific surface area, good thermal and hydrothermal stability, and is promising in applications as catalyst carriers and adsorbents for waste treatment.

  5. Influence of silicate anions structure on desilication in silicate-bearing sodium aluminate solution

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 张闻; 齐天贵; 彭志宏; 周秋生; 李小斌

    2016-01-01

    The structural changes of silicate anions in the desilication process with the addition of calcium hydrate alumino-carbonate were studied by measuring Raman spectra, infrared spectra and corresponding second derivative spectra. The results show that the desilication ratio in the solution prepared by the addition of sodium silicate (solution-SS) is much greater than that in the solution by the addition of green liquor (solution-GL), and low alumina concentration in the sodium aluminate solutions facilitates the desilication process. It is also shown that alumino-silicate anions in the solution-GL, and Q3 polymeric silicate anions in solution-SS are predominant, respectively. In addition, increasing the concentration of silica favors respectively the formation of the alumino-silicate or the Q3 silicate anions in the solution-GL or the solution-SS. Therefore, it can be inferred that the low desilication ratio in the silicate-bearing aluminate solution is mainly attributed to the existence of alumino-silicate anions.

  6. Aluminum, parathyroid hormone, and osteomalacia

    Energy Technology Data Exchange (ETDEWEB)

    Burnatowska-Hledin, M.A.; Kaiser, L.; Mayor, G.H.

    1983-01-01

    Aluminum exposure in man is unavoidable. The occurrence of dialysis dementia, vitamin D-resistant osteomalacia, and hypochromic microcytic anemia in dialysis patients underscores the potential for aluminum toxicity. Although exposure via dialysate and hyperalimentation leads to significant tissue aluminum accumulation, the ubiquitous occurrence of aluminum and the severe pathology associated with large aluminum burdens suggest that smaller exposures via the gastrointestinal tract and lungs could represent an important, though largely unrecognized, public health problem. It is clear that some aluminum absorption occurs with the ingestion of small amounts of aluminum in the diet and medicines, and even greater aluminum absorption is seen in individuals consuming large amounts of aluminum present in antacids. Aluminum absorption is enhanced in the presence of elevated circulating parathyroid hormone. In addition, elevated PTH leads to the preferential deposition of aluminum in brain and bone. Consequently, PTH is likely to be involved in the pathogenesis of toxicities in those organs. PTH excess also seems to lead to the deposition of aluminum in the parathyroid gland. The in vitro demonstration that aluminum inhibits parathyroid hormone release is consistent with the findings of a euparathyroid state in dialysis patients with aluminum related vitamin D-resistant osteomalacia. Nevertheless, it seems likely that hyperparathyroidism is at least initially involved in the pathogenesis of aluminum neurotoxicity and osteomalacia; the increases in tissue aluminum stores are followed by suppression of parathyroid hormone release, which is required for the evolution of osteomalacia. Impaired renal function is not a prerequisite for increased tissue aluminum burdens, nor for aluminum-related organ toxicity. Consequently, it is likely that these diseases will be observed in populations other than those with chronic renal disease.

  7. Fabrication of aluminum foam from aluminum scrap Hamza

    Directory of Open Access Journals (Sweden)

    O. A. Osman1 ,

    2015-02-01

    Full Text Available In this study the optimum parameters affecting the preparation of aluminum foam from recycled aluminum were studied, these parameters are: temperature, CaCO3 to aluminum scrap wt. ratio as foaming agent, Al2O3 to aluminum scrap wt. ratio as thickening agent, and stirring time. The results show that, the optimum parameters are the temperature ranged from 800 to 850oC, CaCO3 to aluminum scrap wt. ratio was 5%, Al2O3 to aluminum scrap wt. ratio was 3% and stirring time was 45 second with stirring speed 1200 rpm. The produced foam apparent densities ranged from 0.40-0.60 g/cm3. The microstructure of aluminum foam was examined by using SEM, EDX and XRD, the results show that, the aluminum pores were uniformly distributed along the all matrices and the cell walls covered by thin oxide film.

  8. Core formation in silicate bodies

    Science.gov (United States)

    Nimmo, F.; O'Brien, D. P.; Kleine, T.

    2008-12-01

    Differentiation of a body into a metallic core and silicate mantle occurs most efficiently if temperatures are high enough to allow at least the metal to melt [1], and is enhanced if matrix deformation occurs [2]. Elevated temperatures may occur due to either decay of short-lived radio-isotopes, or gravitational energy release during accretion [3]. For bodies smaller than the Moon, core formation happens primarily due to radioactive decay. The Hf-W isotopic system may be used to date core formation; cores in some iron meteorites and the eucrite parent body (probably Vesta) formed within 1 My and 1-4~My of solar system formation, respectively [4]. These formation times are early enough to ensure widespread melting and differentiation by 26Al decay. Incorporation of Fe60 into the core, together with rapid early mantle solidification and cooling, may have driven early dynamo activity on some bodies [5]. Iron meteorites are typically depleted in sulphur relative to chondrites, for unknown reasons [6]. This depletion contrasts with the apparently higher sulphur contents of cores in larger planetary bodies, such as Mars [7], and also has a significant effect on the timing of core solidification. For bodies of Moon-size and larger, gravitational energy released during accretion is probably the primary cause of core formation [3]. The final stages of accretion involve large, stochastic collisions [8] between objects which are already differentiated. During each collision, the metallic cores of the colliding objects merge on timescales of a few hours [9]. Each collision will reset the Hf-W isotopic signature of both mantle and core, depending on the degree to which the impactor core re-equilibrates with the mantle of the target [10]. The re-equilibration efficiency depends mainly on the degree to which the impactor emulsifies [11], which is very uncertain. Results from N-body simulations [8,12] suggest that significant degrees of re- equilibration are required [4,10]. Re

  9. Nanostructure of Calcium Silicate Hydrates in Cements

    KAUST Repository

    Skinner, L. B.

    2010-05-11

    Calcium silicate hydrate (CSH) is the major volume phase in the matrix of Portland cement concrete. Total x-ray scattering measurements with synchrotron x rays on synthetic CSH(I) shows nanocrystalline ordering with a particle diameter of 3.5(5) nm, similar to a size-broadened 1.1 nm tobermorite crystal structure. The CSH component in hydrated tricalcium silicate is found to be similar to CSH(I). Only a slight bend and additional disorder within the CaO sheets is required to explain its nanocrystalline structure. © 2010 The American Physical Society.

  10. Electrically conductive anodized aluminum coatings

    Science.gov (United States)

    Alwitt, Robert S. (Inventor); Liu, Yanming (Inventor)

    2001-01-01

    A process for producing anodized aluminum with enhanced electrical conductivity, comprising anodic oxidation of aluminum alloy substrate, electrolytic deposition of a small amount of metal into the pores of the anodized aluminum, and electrolytic anodic deposition of an electrically conductive oxide, including manganese dioxide, into the pores containing the metal deposit; and the product produced by the process.

  11. China’s Aluminum Resources

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> The aluminum industry makes one of the keyindustries in China’s industrial and agriculturalmodernization and features a high degree ofrelevance with all industries.Of all the 124existing industries in China,113 use aluminum,representing an industrial relevance rate of91%.The consumption of aluminum is also ofhigh relevance with China’s GDP.

  12. Aluminum for Plasmonics

    Science.gov (United States)

    2014-01-01

    in plasmon-enhanced light harvesting,14 photocatalysis ,511 surface- enhanced spectroscopies,1216 optics-based sensing,1722 nonlinear optics,2326...optical response of Al nanoparticles has appeared inconsistent relative to calculated spectra, even forwell-characterized geometries. Some studies have...model- ing their optical response. These results pro- vide a method for estimating the metallic purity of aluminum nanoparticles directly from their

  13. 21 CFR 172.410 - Calcium silicate.

    Science.gov (United States)

    2010-04-01

    ... CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Anticaking... agent in food in an amount not in excess of that reasonably required to produce its intended effect. (b... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Calcium silicate. 172.410 Section 172.410 Food...

  14. Stability of calcium silicate in basic solution

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 李小斌; 彭志宏; 周秋生

    2003-01-01

    Mixture of CaO and SiO2 was sintered at 1 200 or 1 400 ℃ according to the mole ratio of CaO/SiO2 of 1 or 2, and then calcium silicate was leached in pure caustic or soda solution. The results indicated that calcium silicate exists much more stably in caustic solution than that in soda solution, and CaO*SiO2 is more stable than β-2CaO*SiO2 whether in caustic solution or in soda solution. The increase of sintering temperature favored the stability of calcium silicate in the leaching process. When β-2CaO*SiO2 was leached in soda solution, the increase of leaching temperature and time resulted in decomposing of more calcium silicate. And when β-2CaO*SiO2 was leached in caustic solution at high temperature, much 2CaO*SiO2*H2O but little CaO*SiO2*H2O appeared in slag.

  15. COMPARISON OF SOL-GEL SILICATE COATINGS ON Ti SUBSTRATE

    OpenAIRE

    2012-01-01

    The objective of the submitted work was to prepare and to characterize two types of silicate coatings prepared by the sol-gel method using the dip-coating technique on a titanium substrate. Efforts have been made to use mechanical properties of bio-inert titanium and bioactive properties of a silicate layer enriched with an admixture of compounds identified below. The first group consisted of silicate coatings containing silver, brushite and monetite. The other group of silicate coatings cont...

  16. The fatty acids and alkanes of Satureja adamovicii Silic and Satureja fukarekii Silic (NOTE

    Directory of Open Access Journals (Sweden)

    DUSANKA KITIC

    1999-05-01

    Full Text Available The content and composition of fatty acids and alkanes of Satureja adamovicii Silic and Satureja fukarekii Silic were analized by GC. It was found that unsaturated acids prevailed and that the major components were palmitic, oleic, linoleic and linolenic acids. The hydrocarbon fractions of pentane extracts were shown to consist of the alkane homologues (C17 to C34 with nonacosane and hentriacontane being prevailing compounds.

  17. 40 CFR 721.9513 - Modified magnesium silicate polymer (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Modified magnesium silicate polymer... Specific Chemical Substances § 721.9513 Modified magnesium silicate polymer (generic). (a) Chemical... as modified magnesium silicate polymer (PMN P-98-604) is subject to reporting under this section...

  18. Characterizing Amorphous Silicates in Extraterrestrial Materials

    Science.gov (United States)

    Fu, X.; Wang, A.; Krawczynski, M. J.

    2015-12-01

    Amorphous silicates are common in extraterrestrial materials. They are seen in the matrix of carbonaceous chondrites as well as in planetary materials. Tagish Lake is one of the most primitive carbonaceous meteorites in which TEM and XRD analyses found evidence for poorly crystalline phyllosilicate-like species; Raman spectra revealed amorphous silicates with variable degree of polymerization and low crystallinity. On Mars, CheMin discovered amorphous phases in all analyzed samples, and poorly crystalline smectite in mudstone samples. These discoveries pose questions on the crystallinity of phyllosilicates found by remote sensing on Mars, which is directly relevant to aqueous alteration during geologic history of Mars. Our goal is to use spectroscopy to better characterize amorphous silicates. We use three approaches: (1) using silicate glasses synthesized with controlled chemistry to study the effects of silicate polymerization and (2) using phyllosilicates synthesized with controlled hydrothermal treatment to study the effect of crystallinity on vibrational spectroscopy, finally (3) to use the developed correlations in above two steps to study amorphous phases in meteorites, and those found in future missions to Mars. In the 1st step, silicate glasses were synthesized from pure oxides in a range of NBO/T ratios (from 0 to 4). Depending on the targeted NBO/T and composition of mixed oxides, temperatures for each experiment fell in a range from 1260 to 1520 °C, run for ~ 4 hrs. The melt was quenched in liquid N2 or water. Homogeneity of glass was checked under optical microscopy. Raman spectra were taken over 100 spots on small chips free of bubbles and crystals. We have observed that accompanying an increase of NBO/T, there is a strengthening and a position shift of the Raman peak near 1000 cm-1 (Si-Onon-bridging stretching mode), and the weakening of broad Raman peaks near 500 cm-1 (ring breathing mode) and 700cm-1 (Si-Obridging-Si mode). We are building the

  19. Aluminum microstructures on anodic alumina for aluminum wiring boards.

    Science.gov (United States)

    Jha, Himendra; Kikuchi, Tatsuya; Sakairi, Masatoshi; Takahashi, Hideaki

    2010-03-01

    The paper demonstrates simple methods for the fabrication of aluminum microstructures on the anodic oxide film of aluminum. The aluminum sheets were first engraved (patterned) either by laser beam or by embossing to form deep grooves on the surface. One side of the sheet was then anodized, blocking the other side by using polymer mask to form the anodic alumina. Because of the lower thickness at the bottom part of the grooves, the part was completely anodized before the complete oxidation of the other parts. Such selectively complete anodizing resulted in the patterns of metallic aluminum on anodic alumina. Using the technique, we fabricated microstructures such as line patterns and a simple wiring circuit-board-like structure on the anodic alumina. The aluminum microstructures fabricated by the techniques were embedded in anodic alumina/aluminum sheet, and this technique is promising for applications in electronic packaging and devices.

  20. Numerical simulation and combination optimization of aluminum holding furnace linings based on simulated annealing☆

    Institute of Scientific and Technical Information of China (English)

    Jimin Wang; Shen Lan; Tao Chen; Wenke Li; Huaqiang Chu

    2015-01-01

    To reduce heat loss and save cost, a combination decision model of reverb aluminum holding furnace linings in aluminum casting industry was established based on economic thickness method, and was resolved using sim-ulated annealing. Meanwhile, a three-dimensional mathematical model of aluminum holding furnace linings was developed and integrated with user-defined heat load distribution regime model. The optimal combination was as follows:side wal with 80 mm alumino-silicate fiber felts, 232 mm diatomite brick and 116 mm chamotte brick;top wall with 50 mm clay castables, 110 mm alumino-silicate fiber felts and 200 mm refractory concrete;and bottom wal with 232 mm high-alumina brick, 60 mm clay castables and 68 mm diatomite brick. Lining tem-perature from high to low was successively bottom wal , side wal , and top wall. Lining temperature gradient in increasing order of magnitude was refractory layer and insulation layer. It was indicated that the results of com-bination optimization of aluminum holding furnace linings were valid and feasible, and its thermo-physical mechanism and cost characteristics were reasonably revealed.

  1. Tracking bubble evolution inside a silicic dike

    Science.gov (United States)

    Álvarez-Valero, Antonio M.; Okumura, Satoshi; Arzilli, Fabio; Borrajo, Javier; Recio, Clemente; Ban, Masao; Gonzalo, Juan C.; Benítez, José M.; Douglas, Madison; Sasaki, Osamu; Franco, Piedad; Gómez-Barreiro, Juan; Carnicero, Asunción

    2016-10-01

    Pressure estimates from rapidly erupted crustal xenoliths constrain the depth of intrusion of the silicic lavas hosting them. This represents an opportunity for tracking magmatic bubble's evolution and quantifying the variation in bubble volume during rapid magma ascent through a volcanic dike just prior to eruption. The petrology, stable-isotope geochemistry and X-ray micro-tomography of dacites containing crustal xenoliths, erupted from a Neogene volcano in SE Spain, showed an increase in porosity from ~ 1.7 to 6.4% from ~ 19 to 13 km depth, at nearly constant groundmass and crystal volumes. This result provides additional constraints for experimental and numerical simulations of subvolcanic magma-crust degassing processes in silicic systems, and may allow the characterization of volcanic eruptive styles based on volatile content.

  2. Recycle of silicate waste into mesoporous materials.

    Science.gov (United States)

    Kim, Jung Ho; Kim, Minwoo; Yu, Jong-Sung

    2011-04-15

    Template synthesis of porous carbon materials usually requires selective removal of template silica from the carbon/silica composites. It not only involves waste of valuable chemicals, but also poses significant environmental concerns including high waste treatment cost. Recycling of silicates released from such nanocasting methods is successfully performed for the first time to regenerate valuable mesoporous MCM and SBA type silica materials, which will not only help in saving valuable chemicals, but also in decreasing chemical waste, contributing in improvement of our environmental standards. This approach can thus improve cost effectiveness for the mass production of nanostructured carbon and others utilizing silica directed nanocasting method by recycling otherwise silicate waste into highly desirable valuable mesoporous silica.

  3. Cooling rate calculations for silicate glasses.

    Science.gov (United States)

    Birnie, D. P., III; Dyar, M. D.

    1986-03-01

    Series solution calculations of cooling rates are applied to a variety of samples with different thermal properties, including an analog of an Apollo 15 green glass and a hypothetical silicate melt. Cooling rates for the well-studied green glass and a generalized silicate melt are tabulated for different sample sizes, equilibration temperatures and quench media. Results suggest that cooling rates are heavily dependent on sample size and quench medium and are less dependent on values of physical properties. Thus cooling histories for glasses from planetary surfaces can be estimated on the basis of size distributions alone. In addition, the variation of cooling rate with sample size and quench medium can be used to control quench rate.

  4. Submarine silicic volcanism: Processes and products

    Digital Repository Service at National Institute of Oceanography (India)

    Kalangutkar, N.G.; Iyer, S.D.

    and these are supported by several experimental studies (Annen et al., 2006). A silicic calc-alkalic magma can form by differentiation from a more mafic parent magma and by crustal anatexis. Several evidences show the origin of some rhyolitic and andesitic magma... to be related due to similar tectonic settings. Fractional crystallisation: This process produces a series of residual liquids of variable compositions as compared to their parental magmas and is best explained by the Bowen’s reaction principle (Bowen, 1922...

  5. Six White Dwarfs with Circumstellar Silicates

    CERN Document Server

    Jura, M; Zuckerman, B

    2008-01-01

    Spitzer Space Telescope spectra reveal 10 micron silicate emission from circumstellar dust orbiting six externally-polluted white dwarfs. Micron-size glasses with an olivine stoichiometry can account for the distinctively broad wings that extend to 12 microns; these particles likely are produced by tidal-disruption of asteroids. The absence of infrared PAH features is consistent with a scenario where extrasolar rocky planets are assembled from carbon-poor solids.

  6. High Pressure Response of Siliceous Materials

    Science.gov (United States)

    2013-02-01

    BOROFLOAT (borosilicate) SCHOTT X Air & Tin X X Air & Tin Fe-containing soda lime silicate Dulles Glass and Mirror X Air & Tin X Air & Tin Opal...hydrated silica) Excalibur Mineral Corporation X X Glass Ceramic ROBAX SCHOTT X X X Single Crystal Ceramic α-Quartz Jim Coleman Crystal...examined in this study conducted by Oak Ridge National Laboratory and sponsored by the US Army TARDEC. Some were glasses (fused silica or fused

  7. Aluminum Carbothermic Technology

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, Marshall J.

    2005-03-31

    This report documents the non-proprietary research and development conducted on the Aluminum Carbothermic Technology (ACT) project from contract inception on July 01, 2000 to termination on December 31, 2004. The objectives of the program were to demonstrate the technical and economic feasibility of a new carbothermic process for producing commercial grade aluminum, designated as the ''Advanced Reactor Process'' (ARP). The scope of the program ranged from fundamental research through small scale laboratory experiments (65 kW power input) to larger scale test modules at up to 1600 kW power input. The tasks included work on four components of the process, Stages 1 and 2 of the reactor, vapor recovery and metal alloy decarbonization; development of computer models; and economic analyses of capital and operating costs. Justification for developing a new, carbothermic route to aluminum production is defined by the potential benefits in reduced energy, lower costs and more favorable environmental characteristics than the conventional Hall-Heroult process presently used by the industry. The estimated metrics for these advantages include energy rates at approximately 10 kWh/kg Al (versus over 13 kWh/kg Al for Hall-Heroult), capital costs as low as $1250 per MTY (versus 4,000 per MTY for Hall-Heroult), operating cost reductions of over 10%, and up to 37% reduction in CO2 emissions for fossil-fuel power plants. Realization of these benefits would be critical to sustaining the US aluminum industries position as a global leader in primary aluminum production. One very attractive incentive for ARP is its perceived ability to cost effectively produce metal over a range of smelter sizes, not feasible for Hall-Heroult plants which must be large, 240,000 TPY or more, to be economical. Lower capacity stand alone carbothermic smelters could be utilized to supply molten metal at fabrication facilities similar to the mini-mill concept employed by the steel industry

  8. Adsorption of dimeric surfactants in lamellar silicates

    Energy Technology Data Exchange (ETDEWEB)

    Balcerzak, Mateusz; Pietralik, Zuzanna [Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland); Domka, Ludwik [Department of Metalorganic Chemistry, Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań (Poland); Skrzypczak, Andrzej [Institute of Chemical Technology, Poznań University of Technology, Berdychowo 4, 60-965 Poznań (Poland); Kozak, Maciej, E-mail: mkozak@amu.edu.pl [Department of Macromolecular Physics, Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznań (Poland)

    2015-12-01

    Highlights: • The intercalation of dimeric surfactants changed the morphology of MMT samples. • XRD indicated structures formed by surfactant molecules in interlayer space. • The four-step thermal decomposition of dimeric surfactant, confirms intercalation. - Abstract: The adsorption of different types of cationic surfactants in lamellar silicates changes their surface character from hydrophilic to hydrophobic. This study was undertaken to obtain lamellar silicates modified by a series of novel dimeric (gemini) surfactants of different length alkyl chains and to characterise these organophilised materials. Synthetic sodium montmorillonite SOMASIF® ME 100 (M) and enriched bentonite of natural origin (Nanoclay – hydrophilic bentonite®) were organophilised with dimeric (gemini) surfactants (1,1′-(1,4-butanediyl)bis(alkoxymethyl)imidazolium dichlorides). As a result of surfactant molecule adsorption in interlamellar space, the d-spacing (d{sub 001}) increased from 0.97 nm (for the anhydrous structure) to 2.04 nm. A Fourier transform infrared spectroscopy (FTIR) analysis of the modified systems reveals bands assigned to the stretching vibrations of the CH{sub 2} and CH{sub 3} groups and the scissoring vibrations of the NH group from the structure of the dimeric surfactants. Thermogravimetric (TG) and derivative thermogravimetric (DTG) studies imply a four-stage process of surfactant decomposition. Scanning electron microscopy (SEM) images provide information on the influence of dimeric surfactant intercalation into the silicate structures. Particles of the modified systems show a tendency toward the formation of irregularly shaped agglomerates.

  9. Laser assisted foaming of aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Kathuria, Y.P. [Laser X Co. Ltd., Aichi (Japan)

    2001-09-01

    Recently aluminum foams have evoked considerable interest as an alternative material owing to their wide range of applications ranging from microelectronics, through automobiles to aerospace industries. The manufacturing techniques and characterization methods for aluminum foams require further development to achieve effective and economical use of this material. In this communication the authors demonstrate the feasibility of unidirectional and localized expansion of the aluminum foam using the Nd-YAG/CO{sub 2} laser and powder metallurgy. (orig.)

  10. Diseases associated with exposure to silica and nonfibrous silicate minerals. Silicosis and Silicate Disease Committee

    Energy Technology Data Exchange (ETDEWEB)

    1988-07-01

    Silicosis, a disease of historical importance, continues to occur cryptically today. Its pathogenesis is under ongoing study as new concepts of pathobiology evolve. In this article, the gross and microscopic features of the disease in the lungs and the lesions in lymph nodes and other viscera are described. These tissue changes are then discussed in the context of clinical disease and other possible or established complications of silica exposure (ie, scleroderma and rheumatoid arthritis, glomerulonephritis, and bronchogenic carcinoma). Silicates are members of a large family of common minerals, some of which have commercial importance. Silicates are less fibrogenic than silica when inhaled into the lungs, but cause characteristic lesions after heavy prolonged exposure. The features of these disease conditions are described herein. Various aspects of the mineralogy and tissue diagnosis of silicosis and lung disease due to silicates are reviewed. An overview of contemporary regulatory considerations is provided.204 references.

  11. Effect of silicate solutions on metakaolinite based cementitious material

    Institute of Scientific and Technical Information of China (English)

    XIAO Xue-jun; LI Hua-jian; SUN Heng-hu

    2006-01-01

    High performance metakaolinite based cementitious materials were prepared with metakaolinite as main component, and the different modules of Na and Na-K silicate solutions as diagenetic agent. The results show that the mechanical properties are affected by different silicate solutions, compressive strengths of pastes hydrated for 3 d and 28 d with Na-K silicate solution (The modulus is 1) are about 43.68 and 78.52 MPa respectively. By analyzing the mechanical properties of Metakaolinite based cementitious materials, the diagenetic effect of lower module is better than higher module, and Na-K silicate solution is better than Na silicate solution. The structure of the Na and Na-K silicate solutions is studied with IR and 29Si NMR, the reason of the lower module and Na-K silicate solution improving the mechanical properties is that the low module silicate solution has lower polymeric degree of silicon dioxide, and the higher polymeric degree of silicon oxide tetrahedron(Q4) in Na-K silicate solution is less than Na silicate solution.

  12. Neurofibrillary pathology and aluminum in Alzheimer's disease

    OpenAIRE

    Shin, R. W.; Lee, V.M.Y.; Trojanowski, J.Q.

    1995-01-01

    Since the first reports of aluminum-induced neurofibrillary degeneration in experimental animals, extensive studies have been performed to clarify the role played by aluminum in the pathogenesis of Alzheimer's disease (AD). Additional evidence implicating aluminum in AD includes elevated levels of aluminum in the AD brain, epidemiological data linking aluminum exposure to AD, and interactions between aluminum and protein components in the pathological lesions o...

  13. Electrokinetic characteristic and coagulation behavior of flocculant polyaluminum silicate chloride (PASiC)

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The electrokinetic characteristics and coagulation behaviors of polyaluminum silicate chloride (PASiC) and polyaluminum chloride (PAC) were studied and compared by streaming current (SC) measurement and jar test method. The experimental results showed that the interaction between polysilicic acid characterized negative charge and hydrolyzed aluminum species result in a decrease of the charge-neutralizing ability of PAiSC, compared to PAC. The decrease has a close relationship with the basicity (B) and Al/Si molar ratio in PASiC. The less the B value and the Al/Si molar ratio, the lower the charge-neutralizing ability of PASiC is. In contrast, the preparation technique for PASiC affects the charge-neutralization of PASiC to a smaller extent. In addition, compared with PAC, PASiC may enhance aggregating efficiency and give better coagulating effects.

  14. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  15. Aluminum Nanoholes for Optical Biosensing

    Directory of Open Access Journals (Sweden)

    Carlos Angulo Barrios

    2015-07-01

    Full Text Available Sub-wavelength diameter holes in thin metal layers can exhibit remarkable optical features that make them highly suitable for (biosensing applications. Either as efficient light scattering centers for surface plasmon excitation or metal-clad optical waveguides, they are able to form strongly localized optical fields that can effectively interact with biomolecules and/or nanoparticles on the nanoscale. As the metal of choice, aluminum exhibits good optical and electrical properties, is easy to manufacture and process and, unlike gold and silver, its low cost makes it very promising for commercial applications. However, aluminum has been scarcely used for biosensing purposes due to corrosion and pitting issues. In this short review, we show our recent achievements on aluminum nanohole platforms for (biosensing. These include a method to circumvent aluminum degradation—which has been successfully applied to the demonstration of aluminum nanohole array (NHA immunosensors based on both, glass and polycarbonate compact discs supports—the use of aluminum nanoholes operating as optical waveguides for synthesizing submicron-sized molecularly imprinted polymers by local photopolymerization, and a technique for fabricating transferable aluminum NHAs onto flexible pressure-sensitive adhesive tapes, which could facilitate the development of a wearable technology based on aluminum NHAs.

  16. Ballistic Evaluation of 2060 Aluminum

    Science.gov (United States)

    2016-05-24

    experiments in Experimental Facilities (EFs) 108 and 106, as well as John Hogan of ARL/AMB, Hugh Walter of Bowhead Science and Technology, and David Handshoe...new aluminum (Al)-based monocoque armored-vehicle hulls such as those of the M2 Bradley Infantry Fighting Vehicles. Also in 2012 the Aluminum

  17. Wettability of Aluminum on Alumina

    Science.gov (United States)

    Bao, Sarina; Tang, Kai; Kvithyld, Anne; Tangstad, Merete; Engh, Thorvald Abel

    2011-12-01

    The wettability of molten aluminum on solid alumina substrate has been investigated by the sessile drop technique in a 10-8 bar vacuum or under argon atmosphere in the temperature range from 1273 K to 1673 K (1000 °C to 1400 °C). It is shown that the reduction of oxide skin on molten aluminum is slow under normal pressures even with ultralow oxygen potential, but it is enhanced in high vacuum. To describe the wetting behavior of the Al-Al2O3 system at lower temperatures, a semiempirical calculation was employed. The calculated contact angle at 973 K (700 °C) is approximately 97 deg, which indicates that aluminum does not wet alumina at aluminum casting temperatures. Thus, a priming height is required for aluminum to infiltrate a filter. Wetting in the Al-Al2O3 system increases with temperature.

  18. Nitridosilicates - a significant extension of silicate chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Schnick, W.; Huppertz, H. [Bayreuth Univ. (Germany). Lab. fuer Anorganische Chemie

    1997-05-01

    A new dimension in silicate chemistry becomes accessible through substitution of oxygen by nitrogen. Multinary nitridosilicates, such as Ln{sub 3}Si{sub 6}N{sub 11} (Ln = La, Ce, Pr, Nd, Sm) shown on the right, are built up from SiN{sub 4} tetrahedra into network structures. Owing to the stability of the covalent Si-N bonds and the high degree of condensation, the nitridosilicates show remarkable chemical and thermal stabilities, similar to Si{sub 3}N{sub 4}. (orig.) 22 refs.

  19. Microbial dissolution of silicate materials. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Schwartzman, D. [Howard Univ., Washington, DC (United States). Dept. of Biology

    1996-03-26

    The objective of this research was to better understand the role of selected thermophilic bacteria in the colonization and dissolution of silicate minerals, with potential applications to the HDR Project. The demonstration of enhanced dissolution from microbial effects is critically dependent on providing a mineral bait within a media deficient in the critical nutrient found in the mineral (e.g., Fe). Reproducible experimental conditions in batch experiments require agitation to expose mineral powders, as well as nearly similar initial conditions for both inoculated cultures and controls. It is difficult, but not impossible to ensure reproducible conditions with microbes favoring filamentous growth habits.

  20. Determination of chlorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.

    1959-01-01

    In a rapid accurate method for the determination of chlorine in silicate rocks, the rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate. The sinter cake is leached with water, the resulting solution is filtered, and the filtrate is acidified with nitric acid. Chlorine is determined by titrating this solution with mercuric nitrate solution using sodium nitroprusside as the indicator. The titration is made in the dark with a beam of light shining through the solution. The end point of the titration is found by visually comparing the intensity of this beam of light with that of a similar beam of light in a reference solution.

  1. LABORATORY INVESTIGATIONS OF SILICATE MUD CONTAMINATION WITH CALCIUM

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    2004-12-01

    Full Text Available The silicate-based drilling fluid is a low solids KCl/polymer system with the addition of soluble sodium or potassium silicate to enhance inhibition and wellbore stability. Silicate-based drilling fluids exhibit remarkable shale and chalk stabilizing properties, resulting in gauge hole and the formation of firm cuttings when drilling reactive shales and soft chalks. Silicates protect shales by in-situ gellation when exposed to the neutral pore fluid and precipitation, which occurs on contact with divalent ions present at the surface of the shale. Also, silicates prevent the dispersion and washouts when drilling soft chalk by reacting with the Ca2+ ions present on chalk surfaces of cutting and wellbore to form a protective film. The silicate-based drilling fluid can be used during drilling hole section through shale interbeded anhydrite formations because of its superior shale stabilizing characteristics. However, drilling through the anhydrite can decrease the silicate concentration and change rheological and filtration fluid properties. So, the critical concentration of calcium ions should be investigated by lab tests. This paper details the mechanism of shale inhibition using silicate-based drilling fluid, and presents results of lab tests conducted to ascertain the effect of Ca2+ ions on silicate level in the fluid and the fluid properties.

  2. Calcium polyphosphate as an additive to zinc-silicate glass ionomer cements.

    Science.gov (United States)

    Valliant, Esther Mae; Gagnier, David; Dickey, Brett Thomas; Boyd, Daniel; Filiaggi, Mark Joseph

    2015-07-01

    Aluminum-free glass ionomer cements (GICs) are under development for orthopedic applications, but are limited by their insufficient handling properties. Here, the addition of calcium polyphosphate (CPP) was investigated as an additive to an experimental zinc-silicate glass ionomer cement. A 50% maximum increase in working time was observed with CPP addition, though this was not clinically significant due to the short working times of the starting zinc-silicate GIC. Surprisingly, CPP also improved the mechanical properties, especially the tensile strength which increased by ∼33% after 30 days in TRIS buffer solution upon CPP addition up to 37.5 wt%. This strengthening may have been due to the formation of ionic crosslinks between the polyphosphate chains and polyacrylic acid. Thus, CPP is a potential additive to future GIC compositions as it has been shown to improve handling and mechanical properties. In addition, CPP may stimulate new bone growth and provide the ability for drug delivery, which are desirable modifications for an orthopedic cement.

  3. Hualu Aluminum Will Construct Large Coal-Power-Aluminum Aluminum Processing Industrial Chain

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    The reporter learned from relevant departments of Baiyin City that in order to further push forward industrial upgrading,fulfill expansion and consolidation of the enterprise,Gansu Hualu Aluminum Co.,Ltd(Hualu Aluminum)will implement Out-Of-City-Into-Park project,

  4. Stability of foams in silicate melts

    Science.gov (United States)

    Proussevitch, Alexander A.; Sahagian, Dork L.; Kutolin, Vladislav A.

    1993-12-01

    Bubble coalescence and the spontaneous disruption of high-porosity foams in silicate melts are the result of physical expulsion of interpore melt (syneresis) leading to bubble coalescence, and diffusive gas exchange between bubbles. Melt expulsion can be achieved either along films between pairs of bubbles, or along Plateau borders which represent the contacts between 3 or more bubbles. Theoretical evaluation of these mechanisms is confirmed by experimental results, enabling us to quantify the relevant parameters and determine stable bubble size and critical film thickness in a foam as a function of melt viscosity, surface tension, and time. Foam stability is controlled primarily by melt viscosity and time. Melt transport leading to coalescence of bubbles proceeds along inter-bubble films for smaller bubbles, and along Plateau borders for larger bubbles. Thus the average bubble size accelerates with time. In silicate melts, the diffusive gas expulsion out of a region of foam is effective only for water (and even then, only at small length scales), as the diffusion of CO 2 is negligible. The results of our analyses are applicable to studies of vesicularity of lavas, melt degassing, and eruption mechanisms.

  5. Silicate mineralogy at the surface of Mercury

    Science.gov (United States)

    Namur, Olivier; Charlier, Bernard

    2017-01-01

    NASA's MESSENGER spacecraft has revealed geochemical diversity across Mercury's volcanic crust. Near-infrared to ultraviolet spectra and images have provided evidence for the Fe2+-poor nature of silicate minerals, magnesium sulfide minerals in hollows and a darkening component attributed to graphite, but existing spectral data is insufficient to build a mineralogical map for the planet. Here we investigate the mineralogical variability of silicates in Mercury's crust using crystallization experiments on magmas with compositions and under reducing conditions expected for Mercury. We find a common crystallization sequence consisting of olivine, plagioclase, pyroxenes and tridymite for all magmas tested. Depending on the cooling rate, we suggest that lavas on Mercury are either fully crystallized or made of a glassy matrix with phenocrysts. Combining the experimental results with geochemical mapping, we can identify several mineralogical provinces: the Northern Volcanic Plains and Smooth Plains, dominated by plagioclase, the High-Mg province, strongly dominated by forsterite, and the Intermediate Plains, comprised of forsterite, plagioclase and enstatite. This implies a temporal evolution of the mineralogy from the oldest lavas, dominated by mafic minerals, to the youngest lavas, dominated by plagioclase, consistent with progressive shallowing and decreasing degree of mantle melting over time.

  6. Stability constants for silicate adsorbed to ferrihydrite

    DEFF Research Database (Denmark)

    Hansen, Hans Christian Bruun; Wetche, T.P.; Raulund-Rasmussen, Karsten;

    1994-01-01

    Intrinsic surface acidity constants (K(a1)intr, K(a2)intr) and surface complexation constant for adsorption of orthosilicate onto synthetic ferrihydrite (K(Si) for the complex = FeOSi(OH)3) have been determined from acid/base titrations in 0.001-0.1 m NaClO4 electrolytes and silicate adsorption...... experiments in 0.01 m NaNO3 electrolyte (pH 3-6). The surface equilibrium constants were calculated according to the two-layer model by Dzombak & Morel (1990). Near equilibrium between protons/hydroxyls in solution and the ferrihydrite surface was obtained within minutes while equilibration with silicate...... required days-weeks, both reactions probably being diffusion controlled. Applying the values for specific surface area and site densities for ferrihydrite used by Dzombak & Morel (1990) (600 m2 g-1, 3.4 mumole m-2) the constants pK(al)intr 6.93 +/- 0.12, pK(a2)intr = 8.72 +/- 0.17 and log K(Si) = 3.62 were...

  7. Research drilling in young silicic volcanoes

    Energy Technology Data Exchange (ETDEWEB)

    Eichelberger, J.C.

    1989-06-30

    Magmatic activity, and particularly silicic magmatic activity, is the fundamental process by which continental crust forms and evolves. The transport of magma from deep crustal reservoirs to the surface is a neglected but important aspect of magmatic phenomena. It encompasses problems of eruptive behavior, hydrothermal circulation, and ore deposition, and must be understood in order to properly interpret deeper processes. Drilling provides a means for determining the relationship of shallow intrusive processes to eruption processes at young volcanoes where eruptions are best understood. Drilling also provides a means for directly observing the processes of heat and mass transfer by which recently emplaced intrusions approach equilibrium with their new environment. Drilling in the Inyo Chain, a 600-year-old chain of volcanic vents in California, has shown the close relationship of silicic eruption to shallow dike emplacement, the control of eruptive style by shallow porous-flow degassing, the origin of obsidian by welding, the development of igneous zonation by viscosity segregation, and the character and size of conduits in relation to well-understood magmatic and phreatic eruptions. 36 refs., 9 figs.

  8. Spray Rolling Aluminum Strip

    Energy Technology Data Exchange (ETDEWEB)

    Lavernia, E.J.; Delplanque, J-P; McHugh, K.M.

    2006-05-10

    Spray forming is a competitive low-cost alternative to ingot metallurgy for manufacturing ferrous and non-ferrous alloy shapes. It produces materials with a reduced number of processing steps, while maintaining materials properties, with the possibility of near-net-shape manufacturing. However, there are several hurdles to large-scale commercial adoption of spray forming: 1) ensuring strip is consistently flat, 2) eliminating porosity, particularly at the deposit/substrate interface, and 3) improving material yield. Through this program, a new strip/sheet casting process, termed spray rolling, has been developed, which is an innovative manufacturing technique to produce aluminum net-shape products. Spray rolling combines the benefits of twin-roll casting and conventional spray forming, showing a promising potential to overcome the above hurdles associated with spray forming. Spray rolling requires less energy and generates less scrap than conventional processes and, consequently, enables the development of materials with lower environmental impacts in both processing and final products. Spray Rolling was developed as a collaborative project between the University of California-Davis, the Colorado School of Mines, the Idaho National Engineering and Environmental Laboratory, and an industry team. The following objectives of this project were achieved: (1) Demonstration of the feasibility of the spray rolling process at the bench-scale level and evaluation of the materials properties of spray rolled aluminum strip alloys; and (2) Demonstration of 2X scalability of the process and documentation of technical hurdles to further scale up and initiate technology transfer to industry for eventual commercialization of the process.

  9. Electrophysical properties of microalloyed alumo-silicate ceramics as active dielectric

    Directory of Open Access Journals (Sweden)

    Purenović Jelena

    2013-01-01

    Full Text Available In this paper, electrophysical properties of porous alumo-silicate ceramics, modified by alloying with magnesium and microalloying with aluminum, were investigated. Complex multiphase system, as active microalloyed ceramics, has specific behavior under influence of external electrical field, which involves changes of dielectric losses and impedance, depending on frequency and temperature. Dielectric properties were measured in the frequency range 20 Hz - 1 MHz. Values for permittivity (εr ranged between 140 - 430. Order of magnitude for electrical resistivity was about 106 Ωm, for impedance 104 - 108 Ω, and loss tangent had values about and greater than 0.05. Current flow through active dielectric takes place through dielectric barrier and throughout conduction bands of thin aluminum and magnesium metal films. Permittivity has nonlinear distribution and complex functional dependences because of significant nonhomogeneity of active microalloyed ceramics. Lower values of electrical resistivity are the result of complex electron and ion transfer of charge through solid phase and pores, with decreased potential barriers height, due to the influence of additives, ingredients and defects. [Projekat Ministarstva nauke Republike Srbije, br. III 45012 i br. ON 172057

  10. The determination of calcium in phosphate, carbonate, and silicate rocks by flame photometer

    Science.gov (United States)

    Kramer, Henry

    1956-01-01

    A method has been developed for the determination of calcium in phosphate, carbonate, and silicate rocks using the Beckman flame photometer, with photomultiplier attachement. The sample is dissolved in hydrofluoric, nitric, and perchloric acids, the hydrofluoric and nitric acids are expelled, a radiation buffer consisting of aluminum, magnesium, iron, sodium, potassium, phosphoric acid, and nitric acid is added, and the solution is atomized in an oxy-hydrogen flame with an instrument setting of 554 mµ. Measurements are made by comparison against calcium standards, prepared in the same manner, in the 0 to 50 ppm range. The suppression of calcium emission by aluminum and phosphate was overcome by the addition of a large excess of magnesium. This addition almost completely restores the standard curve obtained from a solution of calcium nitrate. Interference was noted when the iron concentration in the aspirated solution (including the iron from the buffer) exceeded 100 ppm iron. Other common rock-forming elements did not interfere. The results obtained by this procedure are within ± 2 percent of the calcium oxide values obtained by other methods in the range 1 to 95 percent calcium oxide. In the 0 to 1 percent calcium oxide range the method compares favorably with standard methods.

  11. Tritium release from lithium silicate and lithium aluminate, in-reactor and out-of-reactor

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, A.B. Jr.

    1965-11-03

    Considerable technology has developed for production of tritium in metallic target systems. At normal N-Reactor temperatures ({approximately} 300{degrees}C), aluminum-lithium alloys appear to offer a satisfactory system for tritium production. However, reactor safety requirements have generated interest in a target system which will hold the lithium in place at temperatures to 1200{degrees}C. At the same time, gas retention at irradiation temperatures ({approximately}300{degrees}C) must be acceptable, and extraction of the product must be practical. To determine in-reactor gas release characteristics of the silicate and aluminate materials, targets were irradiated in quartz and aluminum capsules. Following irradiation, the gas (condensible and noncondensible fractions) released in-reactor was recovered by drilling the capsules. Subsequently, the targets were recovered and heated in a laboratory vacuum system to investigate characteristics of tritium and helium evolution as a function of temperature. The experimental procedures are discussed briefly, with details in the Appendix. The results of the study are discussed in terms of in-reactor release and later in terms of laboratory extractions.

  12. Subsurface Aluminum Nitride Formation in Iron-Aluminum Alloys

    Science.gov (United States)

    Bott, June H.

    Transformation-induced plasticity (TRIP) steels containing higher amounts of aluminum than conventional steels are ideal for structural automotive parts due to their mechanical properties. However, the aluminum tends to react with any processing environment at high temperatures and therefore presents significant challenges during manufacturing. One such challenge occurs during secondary cooling, reheating, and hot-rolling and is caused by a reaction with nitrogen-rich atmospheres wherein subsurface aluminum nitride forms in addition to internal and external oxides. The nitrides are detrimental to mechanical properties and cause surface cracks. It is important to understand how these nitrides and oxides form and their consequences for the quality of steel products. This study looks at model iron-aluminum (up to 8 wt.% aluminum) alloys and uses confocal laser scanning microscopy, x-ray diffraction, scanning electron microscopy with energy dispersive x-ray spectrometry, and transmission electron microscopy to study the effect of various conditions on the growth and development of these precipitates in a subsurface oxygen-depleted region. By using model alloys and controlling the experimental atmosphere, this study is able to understand some of the more fundamental materials science behind aluminum nitride formation in aluminum-rich iron alloys and the relationship between internal nitride and oxide precipitation and external oxide scale morphology and composition. The iron-aluminum alloys were heated in N2 atmospheres containing oxygen impurities. It was found that nitrides formed when bulk aluminum content was below 8 wt.% when oxygen was sufficiently depleted due to the internal oxidation. In the samples containing 1 wt.% aluminum, the depth of the internal oxide and nitride zones were in agreement with a diffusion-based model. Increasing aluminum content to 3 and 5 wt% had the effects of modifying the surface-oxide scale composition and increasing its continuity

  13. The shape and composition of interstellar silicate grains

    NARCIS (Netherlands)

    Min, M.; Waters, L.B.F.M.; de Koter, A.; Hovenier, J.W.; Keller, L.P.; Markwick-Kemper, F.

    2007-01-01

    We investigate the composition and shape distribution of silicate dust grains in the interstellar medium. The effects of the amount of magnesium and iron in the silicate lattice are studied in detail. We fit the spectral shape of the interstellar 10 mu m extinction feature as observed towards the ga

  14. Silicate Adsorption in Paddy Soils of Guangdong Province, China

    Institute of Scientific and Technical Information of China (English)

    HUANG Li-Yuan; LI Hua-Xing; ZHANG Xin-Ming; LU Wei-Sheng; LIU Yuan-Jin

    2006-01-01

    Silicate adsorption in eight paddy soils developed from four different parent materials in Guangdong Province, China was examined to obtain fundamental knowledge of silicate adsorption to improve the efficacy of silicate fertilizer use in these areas. A correlation analysis showed that silicate adsorption did not obey the Langmuir equation (r = -0.664-0.301) but did obey the Freundlich and Temkin equations (P ≤ 0.01, r = 0.885-0.990). When the equilibrium silicate concentration (Ci) was less than 45 mg SiO2 kg-1, the adsorption capacity was in the following decreasing order of paddy soils: basalt-derived > Pearl River Delta sediment-derived > granite-derived > sand-shale-derived. Stepwise regression and path analysis showed that for the investigated paddy soils amorphous MnO and Al2O3 were the two most important materials that affected silicate adsorption. Moreover, as Ci increased, amorphous Al2O3 tended to play a more important role in silicate adsorption, while the effects of amorphous MnO on silicate adsorption tended to decrease.

  15. Crystalline silicates in AGB and post-AGB stars

    NARCIS (Netherlands)

    Waters, LBFM; Molster, FJ; LeBertre, T; Lebre, A; Waelkens, C

    1999-01-01

    We discuss ISO spectroscopy of oxygen-rich dust shells surrounding evolved stars. The dust that condenses in the outflows of stars on the Asymptotic Giant Branch consists mainly of amorphous silicates and simple oxides. For high mass loss rates, crystalline silicates begin to appear at modest abunda

  16. Petrophysical Analysis of Siliceous Ooze Sediments, Ormen Lange Field, Norway

    DEFF Research Database (Denmark)

    Awedalkarim, Ahmed; Fabricius, Ida Lykke

    Skeletal remains of siliceous algae form biogenic fine grained highly porous pelagic siliceous ooze sediments that were found above the reservoir of the Ormen Lange gas field which is located in the southern part of the Norwegian Sea (Figure 1a). The Palaeocene sandstone of the “Egga” Formation i...

  17. Optical Properties of Astronomical Silicates in the Far-infrared

    Science.gov (United States)

    Rinehart, Stephen A,; Benford, Dominic J.; Dwek, Eli; Henry, Ross M.; Nuth, Joseph A., III; Silverberg, Robert f.; Wollack, Edward J.

    2008-01-01

    Correct interpretation of a vast array of astronomical data relies heavily on understanding the properties of silicate dust as a function of wavelength, temperature, and crystallinity. We introduce the QPASI-T (Optical Properties of Astronomical Silicates with Infrared Techniques) project to address the need for high fidelity optical characterization data on the various forms of astronomical dust. We use two spectrometers to provide extinction data for silicate samples across a wide wavelength range (from the near infrared to the millimeter). New experiments are in development that will provide complementary information on the emissivity of our samples, allowing us to complete the optical characterization of these dust materials. In this paper, we present initial results from several materials including amorphous iron silicate, magnesium silicate and silica smokes, over a wide range of temperatures, and discuss the design and operation of our new experiments.

  18. Thermal Ablation Modeling for Silicate Materials

    Science.gov (United States)

    Chen, Yih-Kanq

    2016-01-01

    A thermal ablation model for silicates is proposed. The model includes the mass losses through the balance between evaporation and condensation, and through the moving molten layer driven by surface shear force and pressure gradient. This model can be applied in ablation simulations of the meteoroid or glassy Thermal Protection Systems for spacecraft. Time-dependent axi-symmetric computations are performed by coupling the fluid dynamics code, Data-Parallel Line Relaxation program, with the material response code, Two-dimensional Implicit Thermal Ablation simulation program, to predict the mass lost rates and shape change. For model validation, the surface recession of fused amorphous quartz rod is computed, and the recession predictions reasonably agree with available data. The present parametric studies for two groups of meteoroid earth entry conditions indicate that the mass loss through moving molten layer is negligibly small for heat-flux conditions at around 1 MW/cm(exp. 2).

  19. Organic modification of layered silicates. Structural and thermal characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Prado, L.A.S. de A.; Schulte, K. [Polymer Composites, Denickstrasse 15, TU Hamburg-Harburg, D-21073 Hamburg (Germany); Karthikeyan, C.S.; Nunes, S.P. [Institute of Chemistry, GKSS Research Centre, Max-Planck Strasse 1, D-21502 Geesthacht (Germany); De Torriani, Iris L. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Cidade Universitaria Zeferino Vaz, CEP 13083-970, Campinas-SP (Brazil)

    2005-05-01

    Organic modification of natural and synthetic layered silicates namely montmorillonite and laponite is reported in this work. The modified silicates are being subsequently used in the preparation of nano-composite membranes based on ionomers for fuel cells application. Laponite, an entirely synthetic silicate, was modified using organosiloxanes containing imidazole groups. Two different strategies were adopted for modification: (a) swelling of the silicate in 2-butanone followed by functionalization using the siloxane at room temperature, (b) direct reaction between laponite and the organosiloxane in xylene at 120{sup o}C. Montmorillonite, a natural silicate, was supplied in the alkyl-ammonium form containing -OH groups. The modification of this silicate was conducted following the procedure (b). The structures of both plain and modified silicates were investigated by XRD showing that the interlayer distance (around 17A) was not affected during the functionalization of laponite. However, a noticeable increase in the interlayer distance from 18.0A to 24.5A was observed for the modified montmorillonite. This clearly shows the presence of polysiloxane chains in between the silicate layers. Further characterization showed that the modification of these silicates was in the range between 16% and 23% (molar percentage). TGA was done between 25 and 300{sup o}C in order to study the thermal degradation pattern of the silicates. The amount of adsorbed water could be determined from the results. The functionalization reduced the adsorption of water from 13.5% to 6.8% for laponite and from 8.5% to 4% for montmorillonite.

  20. Disordered Silicates in Space: a Study of Laboratory Spectra of "Amorphous" Silicates

    CERN Document Server

    Speck, Angela K; Hofmeister, Anne M

    2011-01-01

    We present a laboratory study of silicate glasses of astrophysically relevant compositions including olivines, pyroxenes and melilites. With emphasis on the classic Si-O stretching feature near 10 microns, we compare infrared spectra of our new samples with laboratory spectra on ostensibly similar compositions, and also with synthetic silicate spectral data commonly used in dust modeling. Several different factors affect spectral features including sample chemistry (e.g., polymerization, Mg/Fe ratio, oxidation state and Al-content) and different sample preparation techniques lead to variations in porosity, density and water content. The convolution of chemical and physical effects makes it difficult to attribute changes in spectral parameters to any given variable. It is important that detailed chemical and structural characterization be provided along with laboratory spectra. In addition to composition and density, we measured the glass transition temperatures for the samples which place upper limits on the ...

  1. Interstellar Silicate Dust in the z=0.89 Absorber Towards PKS 1830-211: Crystalline Silicates at High Redshift?

    CERN Document Server

    Aller, Monique C; York, Donald G; Vladilo, Giovanni; Welty, Daniel E; Som, Debopam

    2012-01-01

    We present evidence of a >10-sigma detection of the 10 micron silicate dust absorption feature in the spectrum of the gravitationally lensed quasar PKS 1830-211, produced by a foreground absorption system at redshift 0.886. We have examined more than 100 optical depth templates, derived from both observations of Galactic and extragalactic sources and laboratory measurements, in order to constrain the chemical structure of the silicate dust. We find that the best fit to the observed absorption profile is produced by laboratory crystalline olivine, with a corresponding peak optical depth of tau_10=0.27+/-0.05. The fit is slightly improved upon by including small contributions from additional materials such as silica, enstatite, or serpentine, which suggests that the dust composition may consist of a blend of crystalline silicates. Combining templates for amorphous and crystalline silicates, we find that the fraction of crystalline silicates needs to be at least 95%. Given the rarity of extragalactic sources wit...

  2. INTERSTELLAR SILICATE DUST IN THE z = 0.89 ABSORBER TOWARD PKS 1830-211: CRYSTALLINE SILICATES AT HIGH REDSHIFT?

    Energy Technology Data Exchange (ETDEWEB)

    Aller, Monique C.; Kulkarni, Varsha P.; Som, Debopam [Department of Physics and Astronomy, University of South Carolina, 712 Main Street, Columbia, SC 29208 (United States); York, Donald G.; Welty, Daniel E. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Vladilo, Giovanni, E-mail: ALLERM@mailbox.sc.edu [Osservatorio Astonomico di Trieste, Via Tiepolo 11, 34143 Trieste (Italy)

    2012-03-20

    We present evidence of a >10{sigma} detection of the 10 {mu}m silicate dust absorption feature in the spectrum of the gravitationally lensed quasar PKS 1830-211, produced by a foreground absorption system at redshift 0.886. We have examined more than 100 optical depth templates, derived from both observations of Galactic and extragalactic sources and laboratory measurements, in order to constrain the chemical structure of the silicate dust. We find that the best fit to the observed absorption profile is produced by laboratory crystalline olivine, with a corresponding peak optical depth of {tau}{sub 10} = 0.27 {+-} 0.05. The fit is slightly improved upon by including small contributions from additional materials, such as silica, enstatite, or serpentine, which suggests that the dust composition may consist of a blend of crystalline silicates. Combining templates for amorphous and crystalline silicates, we find that the fraction of crystalline silicates needs to be at least 95%. Given the rarity of extragalactic sources with such a high degree of silicate crystallinity, we also explore the possibility that the observed spectral features are produced by amorphous silicates in combination with other molecular or atomic transitions, or by foreground source contamination. While we cannot rule out these latter possibilities, they lead to much poorer profile fits than for the crystalline olivine templates. If the presence of crystalline interstellar silicates in this distant galaxy is real, it would be highly unusual, given that the Milky Way interstellar matter contains essentially only amorphous silicates. It is possible that the z = 0.886 absorber toward PKS 1830-211, well known for its high molecular content, has a unique star-forming environment that enables crystalline silicates to form and prevail.

  3. Invisible Display in Aluminum

    DEFF Research Database (Denmark)

    Prichystal, Jan Phuklin; Hansen, Hans Nørgaard; Bladt, Henrik Henriksen

    2005-01-01

    Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish for an integ...... be obtained by shining light from the backside of the workpiece. When there is no light from the backside, the front surface seems totally untouched. This was achieved by laser ablation with ultra-short pulses.......Bang & Olufsen a/s has been working with ideas for invisible integration of displays in metal surfaces. Invisible integration of information displays traditionally has been possible by placing displays behind transparent or semitransparent materials such as plastic or glass. The wish...... for an integrated display in a metal surface is often ruled by design and functionality of a product. The integration of displays in metal surfaces requires metal removal in order to clear the area of the display to some extent. The idea behind an invisible display in Aluminum concerns the processing of a metal...

  4. Anodized aluminum on LDEF

    Science.gov (United States)

    Golden, Johnny L.

    1993-01-01

    A compilation of reported analyses and results obtained for anodized aluminum flown on the Long Duration Exposure Facility (LDEF) was prepared. Chromic acid, sulfuric acid, and dyed sulfuric acid anodized surfaces were exposed to the space environment. The vast majority of the anodized surface on LDEF was chromic acid anodize because of its selection as a thermal control coating for use on the spacecraft primary structure, trays, tray clamps, and space end thermal covers. Reports indicate that the chromic acid anodize was stable in solar absorptance and thermal emittance, but that contamination effects caused increases in absorptance on surfaces exposed to low atomic oxygen fluences. There were some discrepancies, however, in that some chromic acid anodized specimens exhibited significant increases in absorptance. Sulfuric acid anodized surfaces also appeared stable, although very little surface area was available for evaluation. One type of dyed sulfuric acid anodize was assessed as an optical baffle coating and was observed to have improved infrared absorptance characteristics with exposure on LDEF.

  5. The shape and composition of interstellar silicate grains

    CERN Document Server

    Min, M; De Koter, A; Hovenier, J W; Keller, L P; Markwick-Kemper, F

    2006-01-01

    We investigate the composition and shape distribution of silicate dust grains in the interstellar medium. The effect of the amount of magnesium in the silicate lattice is studied. We fit the spectral shape of the interstellar 10 mu extinction feature as observed towards the galactic center. We use very irregularly shaped coated and non-coated porous Gaussian Random Field particles as well as a statistical approach to model shape effects. For the dust materials we use amorphous and crystalline silicates with various composition and SiC. The results of our analysis of the 10 mu feature are used to compute the shape of the 20 mu silicate feature and to compare this with observations. By using realistic particle shapes we are, for the first time, able to derive the magnesium fraction in interstellar silicates. We find that the interstellar silicates are highly magnesium rich (Mg/(Fe+Mg)>0.9) and that the stoichiometry lies between pyroxene and olivine type silicates. This composition is not consistent with that o...

  6. Behavior of calcium silicate hydrate in aluminate solution

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-bin; ZHAO Zhuo; LIU Gui-hua; ZHOU Qiu-sheng; PENG Zhi-hong

    2005-01-01

    Using calcium hydroxide and sodium silicate as starting materials, two kinds of calcium silicate hydrates, CaO · SiO2 · H2O and 2CaO · SiO2 · 1.17H2O, were hydro-thermally synthesized at 120 ℃. The reaction rule of calcium silicate hydrate in aluminate solution was investigated. The result shows that CaO · SiO2 · H2O is more stable than 2CaO · SiO2 · 1.17H2 O in aluminate solution and its stability increases with the increase of reaction temperature but decreases with the increase of caustic concentration. The reaction between calcium silicate hydrate and aluminate solution is mainly through two routes. In the first case, Al replaces partial Si in calcium silicate hydrate, meanwhile 3CaO · Al2 O3 · xSiO2 · (6-2x) H2 O (hydro-garnet) is formed and some SiO2 enters the solution. In the second case, calcium silicate hydrate can react directly with aluminate solution, forming hydro-garnet and Na2O · Al2O3 · 2SiO2 · nH2O (DSP). The desilication reaction of aluminate solution containing silicate could contribute partially to forming DSP.

  7. Deep ocean biogeochemistry of silicic acid and nitrate

    Science.gov (United States)

    Sarmiento, J. L.; Simeon, J.; Gnanadesikan, A.; Gruber, N.; Key, R. M.; Schlitzer, R.

    2007-03-01

    Observations of silicic acid and nitrate along the lower branch of the global conveyor belt circulation show that silicic acid accumulation by diatom opal dissolution occurs at 6.4 times the rate of nitrate addition by organic matter remineralization. The export of opal and organic matter from the surface ocean occurs at a Si:N mole ratio that is much smaller than this almost everywhere (cf. Sarmiento et al., 2004). The preferential increase of silicic acid over nitrate as the deep circulation progresses from the North Atlantic to the North Pacific is generally interpreted as requiring deep dissolution of opal together with shallow remineralization of organic matter (Broecker, 1991). However, Sarmiento et al. (2004) showed that the primary reason for the low silicic acid concentration of the upper ocean is that the waters feeding the main thermocline from the surface Southern Ocean are depleted in silicic acid relative to nitrate. By implication, the same Southern Ocean processes that deplete the silicic acid in the surface Southern Ocean must also be responsible for the enhanced silicic acid concentration of the deep ocean. We use observations and results from an updated version of the adjoint model of Schlitzer (2000) to confirm that this indeed the case.

  8. Gas evolution behavior of aluminum in mortar

    Energy Technology Data Exchange (ETDEWEB)

    Hashizume, Shuji; Matsumoto, Junko; Banba, Tsunetaka [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-10-01

    As a part of study of leaching behavior for solidified dry low level radioactive waste, gas evolution behavior of aluminum in mortar was investigated, and a plan of our research was proposed. The effect of pH on corrosion rate of aluminum, corrosion product, time dependency of corrosion rate of aluminum in mortar, change of corrosion mechanism, the effects of Na, Ca and Cl ions on corrosion rate of aluminum in mortar and corrosion behavior of aluminum when aluminum was used as sacrificed anode in reinforced concrete were previously clarified. Study of the effects of environmental factors such as pH, kind of ions and temperature on gas evolution behavior of aluminum and the effect of aluminum/carbon steel surface ratio no gas evolution behavior of aluminum were planed. (author). 75 refs.

  9. Low-aluminum content iron-aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J. [and others

    1995-06-01

    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10 and iron = 83.71. The ignots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot-worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  10. Preparation and Characterization of Amorphous Layer on Aluminum Alloy Formed by Plasma Electrolytic Deposition (PED)

    Institute of Scientific and Technical Information of China (English)

    GUAN Yong-jun; XIA Yuan

    2004-01-01

    In this investigation, protective layers were formed on aluminum substrate by Plasma Electrolytic Deposition (PED) using sodium silicate solution. The relation between the thickness of the layer and process time were studied. XRD,SEM, EDS were used to study the layer's structure, composition and micrograph. The results show that the deposited layers are amorphous and contain mainly oxygen, silicon, and aluminum. The possible formation mechanism of amorphous [Al-Si-O] layer was proposed: During discharge periods, Al2O3 phase of the passive film and SiO32-near the substrate surface are sintered into xSiO2(1-x)Al2O3 and then transformed into amorphous [Al-Si-O] phase.

  11. Functional substitution of coordination polyhedron in crystal structure of silicates

    Institute of Scientific and Technical Information of China (English)

    叶大年; 马哲生; 赫伟; 李哲; 施倪承; D.Pushcharovsky

    2002-01-01

    On the bases of the study of comparative crystal chemistry of silicates it has been concluded that the octahedra and square pyramids of Ti-0 and Zr-O play functional role of tetrahedra of Si-O in the construction of crystal structures. Therefore, those silicates may be named titano-and zircono-silicates. Because of the functional similarity of coordination polyhedra, the structures of cristobalite and feldspar have been compared with those of perovskite and garnet, respectively. As a new concept, the functional replacement of tetrahedra by octahedra and/or pyramids is defined by the authors of this paper for favorable comparison of relative crystal structures.

  12. Fire Resistance of Wood Impregnated with Soluble Alkaline Silicates

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Giudice

    2007-01-01

    Full Text Available The aim of this paper is to determine the fire performance of wood panels (Araucaria angustifolia impregnated with soluble alkaline silicates. Commercial silicates based on sodium and potassium with 2.5/1.0 and 3.0/1.0 silica/alkali molar ratios were selected; solutions and glasses were previously characterized. Experimental panels were tested in a limiting oxygen chamber and in a two-foot tunnel. Results displayed a high fire-retardant efficiency using some soluble silicates.

  13. Journal of the Chinese Silicate Society (Selected Articles).

    Science.gov (United States)

    2014-09-26

    A-A157 497 JOURNAL OF THE CHINESE SILICATE SOCIETY (SELECTED i/i ARTICLES)(U) FOREIGN TECHNOLOGY DIV IWRIGHT-PRT RSON U CLSS..AFE OH 11 JUN 85...7 V- V 17 -, 7Z I T7. k. V.-.’.~. W ~ . FTD-ID(RS)T-0160-85 FOREIGN TECHNOLOGY DIVISION JOURNAL OF THE CHINESE SILICATE SOCIETY... JOURNAL OF THE CHINESE SILICATE SOCIETY D- At"Ibutilonf (Selected Articles) Availability Cadm English pages: 28 Dist ’Avail ald/zr Source: Guisuanyan

  14. Scaleable Clean Aluminum Melting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Han, Q.; Das, S.K. (Secat, Inc.)

    2008-02-15

    The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the program would couple heater improvements with furnace modeling that would enable cost-effective retrofits to a range of existing furnace sizes, reducing the economic barrier to application.

  15. Nanostructure of Er3+ doped silicates.

    Science.gov (United States)

    Yao, Nan; Hou, Kirk; Haines, Christopher D; Etessami, Nathan; Ranganathan, Varadh; Halpern, Susan B; Kear, Bernard H; Klein, Lisa C; Sigel, George H

    2005-06-01

    We demonstrate nanostructural evolution resulting in highly increased photoluminescence in silicates doped with Er3+ ions. High-resolution transmission electron microscopy (HRTEM) imaging, nano-energy dispersed X-ray (NEDX) spectroscopy, X-ray diffraction (XRD) and photoluminescence analysis confirm the local composition and structure changes of the Er3+ ions upon thermal annealing. We studied two types of amorphous nanopowder: the first is of the composition SiO2/18Al2O3/2Er2O3 (SAE), synthesized by combustion flame-chemical vapor condensation, and the second is with a composition of SiO2/8Y2O3/2Er2O3 (SYE), synthesized by sol-gel synthesis (composition in mol%). Electron diffraction and HRTEM imaging clearly show the formation of nanocrystallites with an average diameter of approximately 8 nm in SAE samples annealed at 1000 degrees C and SYE samples annealed at 1200 degrees C. The volume fraction of the nanocrystalline phase increased with each heat treatment, eventually leading to complete devitrification at 1400 degrees C. Further XRD and NEDX analysis indicates that the nanocrystalline phase has the pyrochlore structure with the formula Er(x)Al(2-x)Si2O7 or Er(x)Y(2-x)Si2O7 and a surrounding silica matrix.

  16. The crystalline fraction of interstellar silicates in starburst galaxies

    CERN Document Server

    Kemper, F; Woods, Paul M

    2010-01-01

    We present a model using the evolution of the stellar population in a starburst galaxy to predict the crystallinity of the silicates in the interstellar medium of this galaxy. We take into account dust production in stellar ejecta, and amorphisation and destruction in the interstellar medium and find that a detectable amount of crystalline silicates may be formed, particularly at high star formation rates, and in case supernovae are efficient dust producers. We discuss the effect of dust destruction and amorphisation by supernovae, and the effect of a low dust-production efficiency by supernovae, and find that when taking this into account, crystallinity in the interstellar medium becomes hard to detect. Levels of 6.5-13% crystallinity in the interstellar medium of starburst galaxies have been observed and thus we conclude that not all these crystalline silicates can be of stellar origin, and an additional source of crystalline silicates associated with the Active Galactic Nucleus must be present.

  17. Silicate Urolithiasis during Long-Term Treatment with Zonisamide

    Directory of Open Access Journals (Sweden)

    Satoru Taguchi

    2013-01-01

    Full Text Available Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for peptic ulcers over a long period of time; however, there also existed unrelated cases, whose mechanism of development remains unclear. On the other hand, zonisamide, a newer antiepileptic drug, is one of the important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and then promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells. Here, we report a case of silicate urolithiasis during long-term treatment with zonisamide without magnesium trisilicate intake and discuss the etiology of the disease by examining the silicate concentration in his urine.

  18. Spinning dust emission from ultrasmall silicates: emissivity and polarization spectrum

    CERN Document Server

    Hoang, Thiem; Lan, Nguyen Quynh

    2016-01-01

    Anomalous microwave emission (AME) is an important Galactic foreground of Cosmic Microwave Background (CMB) radiation. It is believed that the AME arises from rotational emission by spinning polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM). In this paper, we assume that a population of ultrasmall silicate grains may exist in the ISM, and quantify rotational emissivity from these tiny particles and its polarization spectrum. We found that spinning silicate nanoparticles can produce strong rotational emission when those small grains follow a log-normal size distribution. The polarization fraction of spinning dust emission from tiny silicates increases with decreasing the dipole moment per atom ($\\beta$) and can reach $P\\sim 20\\%$ for $\\beta\\sim 0.1$D at grain temperature of 60 K. We identify a parameter space $(\\beta,Y_{Si})$ for silicate nanoparticles in which its rotational emission can adequately reproduce both the observed AME and the polarization of the AME, without violating the ob...

  19. Characterization of iron-phosphate-silicate chemical garden structures.

    Science.gov (United States)

    Barge, Laura M; Doloboff, Ivria J; White, Lauren M; Stucky, Galen D; Russell, Michael J; Kanik, Isik

    2012-02-28

    Chemical gardens form when ferrous chloride hydrate seed crystals are added or concentrated solutions are injected into solutions of sodium silicate and potassium phosphate. Various precipitation morphologies are observed depending on silicate and phosphate concentrations, including hollow plumes, bulbs, and tubes. The growth of precipitates is controlled by the internal osmotic pressure, fluid buoyancy, and membrane strength. Additionally, rapid bubble-led growth is observed when silicate concentrations are high. ESEM/EDX analysis confirms compositional gradients within the membranes, and voltage measurements across the membranes during growth show a final potential of around 150-200 mV, indicating that electrochemical gradients are maintained across the membranes as growth proceeds. The characterization of chemical gardens formed with iron, silicate, and phosphate, three important components of an early earth prebiotic hydrothermal system, can help us understand the properties of analogous structures that likely formed at submarine alkaline hydrothermal vents in the Hadean-structures offering themselves as the hatchery of life.

  20. Properties of sodium silicate bonded sand hardened by microwave heating

    Institute of Scientific and Technical Information of China (English)

    Wang Jina; Fan Zitian; Zan Xiaolei; Pan Di

    2009-01-01

    The sodium silicate bonded sand hardened by microwave heating has many advantages,such as low sodium silicate adding quantity,fast hardening speed,high room temperature strength,good collapsibility and certain surface stability. However,it has big moisture absorbability in the air,which would lead to the compression strength and the surface stability of the sand molds being sharply reduced. In this study,the moisture absorbability of the sodium silicate bonded sand hardened by microwave heating in different humidity conditions and the effect factors were investigated. Meanwhile,the reasons for the big moisture absorbability of the sand were analyzed.Some measures to overcome the problems of high moisture absorbability,bad surface stability and sharply reducing strength in the air were discussed. The results of this study establish the foundation of green and clean foundry technology based on the microwave heating hardening sodium silicate sand process.

  1. Determination of reactivity rates of silicate particle-size fractions

    OpenAIRE

    Angélica Cristina Fernandes Deus; Leonardo Theodoro Büll; Juliano Corulli Corrêa; Roberto Lyra Villas Boas

    2014-01-01

    The efficiency of sources used for soil acidity correction depends on reactivity rate (RR) and neutralization power (NP), indicated by effective calcium carbonate (ECC). Few studies establish relative efficiency of reactivity (RER) for silicate particle-size fractions, therefore, the RER applied for lime are used. This study aimed to evaluate the reactivity of silicate materials affected by particle size throughout incubation periods in comparison to lime, and to calculate the RER for silicat...

  2. Decreasing residual aluminum level in drinking water

    Institute of Scientific and Technical Information of China (English)

    王志红; 崔福义

    2004-01-01

    The relativity of coagulant dosage, residual turbidity, temperature, pH etc. with residual aluminum concentration were investigated, and several important conclusions were achieved. Firstly, dosage of alum-coagulant or PAC1 influences residual aluminum concentration greatly. There is an optimal-dosage-to-aluminum, a bit less than the optimal-dosage-to-turbidity. Secondly, it proposes that decreasing residual aluminum concentration can be theoretically divided into two methods, either decreasing (even removing) the concentration of particulate aluminum component, or decreasing dissolved aluminum. In these tests there is an optimal value of residual turbidity of postprecipitation at 7.0 NTU. Thirdly, residual aluminum level will increase while water temperature goes higher. At the last, optimal pH value corresponds a minimum dissolved aluminum at a given turbidity. Data shows the optimal pH value decreases with water temperature's increasing.

  3. 21 CFR 172.310 - Aluminum nicotinate.

    Science.gov (United States)

    2010-04-01

    ... Special Dietary and Nutritional Additives § 172.310 Aluminum nicotinate. Aluminum nicotinate may be safely... additive, expressed as niacin, shall appear on the label of the food additive container or on that of...

  4. Environmental Control over the Primary Aluminum Industry

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> To strengthen environmental control over theprimary aluminum industry,the State Environ-mental Protection Administration of China hasrecently issued a notice addressing the follow-ing points:Strengthening environmental control over theexisting primary aluminum companies

  5. OPTIMIZING AN ALUMINUM EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Mohammed Ali Hajeeh

    2013-01-01

    Full Text Available Minimizing the amount of scrap generated in an aluminum extrusion process. An optimizing model is constructed in order to select the best cutting patterns of aluminum logs and billets of various sizes and shapes. The model applied to real data obtained from an existing extrusion factory in Kuwait. Results from using the suggested model provided substantial reductions in the amount of scrap generated. Using sound mathematical approaches contribute significantly in reducing waste and savings when compared to the existing non scientific techniques.

  6. High Pressure/Temperature Metal Silicate Partitioning of Tungsten

    Science.gov (United States)

    Shofner, G. A.; Danielson, L.; Righter, K.; Campbell, A. J.

    2010-01-01

    The behavior of chemical elements during metal/silicate segregation and their resulting distribution in Earth's mantle and core provide insight into core formation processes. Experimental determination of partition coefficients allows calculations of element distributions that can be compared to accepted values of element abundances in the silicate (mantle) and metallic (core) portions of the Earth. Tungsten (W) is a moderately siderophile element and thus preferentially partitions into metal versus silicate under many planetary conditions. The partitioning behavior has been shown to vary with temperature, silicate composition, oxygen fugacity, and pressure. Most of the previous work on W partitioning has been conducted at 1-bar conditions or at relatively low pressures, i.e. <10 GPa, and in two cases at or near 20 GPa. According to those data, the stronger influences on the distribution coefficient of W are temperature, composition, and oxygen fugacity with a relatively slight influence in pressure. Predictions based on extrapolation of existing data and parameterizations suggest an increased pressured dependence on metal/ silicate partitioning of W at higher pressures 5. However, the dependence on pressure is not as well constrained as T, fO2, and silicate composition. This poses a problem because proposed equilibration pressures for core formation range from 27 to 50 GPa, falling well outside the experimental range, therefore requiring exptrapolation of a parametereized model. Higher pressure data are needed to improve our understanding of W partitioning at these more extreme conditions.

  7. Friction and Wear Behaviors of Nano-Silicates in Water

    Institute of Scientific and Technical Information of China (English)

    Chen Boshui; Lou Fang; Fang Jianhua; Wang Jiu; Li Jia

    2009-01-01

    Nano-metric magnesium silicate and zinc silicate with particle size of about 50--70nm were prepared in water by the method of chemical deposition. The antiwear and friction reducing abilities of the nano-silicates, as well as their compos-ites with oleie acid tri-ethanolamine (OATEA), were evaluated on a four-ball friction tester. The topographies and tribochemical features of the worn surfaces were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). Results show that nano-silicates alone provide poor antiwear and friction reducing abilities in water, but exhibits excellent synergism with OATEA in reducing friction and wear. The synergism in reducing friction and wear between naao-silicates and OATEA does exist almost regardless of particle sizes and species, and may be attributed, on one hand, to the formation of an adsorption film of OATEA, and, on the other hand, to the formation oftdbochemical species of silicon dioxide and iron oxides on the friction surfaces. Tribo-reactions and tribo-adsorptions of nano-silicates and OATEA would produce hereby an effective composite boondary lubrication film, which could efficiently enhance the anti-wear and friction-reducing abilities of water.

  8. The effect of zinc on the aluminum anode of the aluminum-air battery

    Science.gov (United States)

    Tang, Yougen; Lu, Lingbin; Roesky, Herbert W.; Wang, Laiwen; Huang, Baiyun

    Aluminum is an ideal material for batteries, due to its excellent electrochemical performance. Herein, the effect of zinc on the aluminum anode of the aluminum-air battery, as an additive for aluminum alloy and electrolytes, has been studied. The results show that zinc can decrease the anodic polarization, restrain the hydrogen evolution and increase the anodic utilization rate.

  9. Electrochemical Behavior of Aluminum in Nitric Acid

    Institute of Scientific and Technical Information of China (English)

    CHEN; Hui; ZHU; Li-yang; LIN; Ru-shan; TAN; Hong-bin; HE; Hui

    2013-01-01

    Aluminum is one of cladding materials for nuclear fuel,it is important to investigate the electrolytic dissolution of aluminum in nitric acid.The electrochemical impedance spectroscopy,polarization curve and cyclic voltammetry cure of anodic aluminum electrode in nitric acid under various conditions were collected(Fig.1).It turns out,under steady state,the thickness of the passivated film of aluminum

  10. Metal and silicate particles including nanoparticles are present in electronic cigarette cartomizer fluid and aerosol.

    Directory of Open Access Journals (Sweden)

    Monique Williams

    Full Text Available Electronic cigarettes (EC deliver aerosol by heating fluid containing nicotine. Cartomizer EC combine the fluid chamber and heating element in a single unit. Because EC do not burn tobacco, they may be safer than conventional cigarettes. Their use is rapidly increasing worldwide with little prior testing of their aerosol.We tested the hypothesis that EC aerosol contains metals derived from various components in EC.Cartomizer contents and aerosols were analyzed using light and electron microscopy, cytotoxicity testing, x-ray microanalysis, particle counting, and inductively coupled plasma optical emission spectrometry.The filament, a nickel-chromium wire, was coupled to a thicker copper wire coated with silver. The silver coating was sometimes missing. Four tin solder joints attached the wires to each other and coupled the copper/silver wire to the air tube and mouthpiece. All cartomizers had evidence of use before packaging (burn spots on the fibers and electrophoretic movement of fluid in the fibers. Fibers in two cartomizers had green deposits that contained copper. Centrifugation of the fibers produced large pellets containing tin. Tin particles and tin whiskers were identified in cartridge fluid and outer fibers. Cartomizer fluid with tin particles was cytotoxic in assays using human pulmonary fibroblasts. The aerosol contained particles >1 µm comprised of tin, silver, iron, nickel, aluminum, and silicate and nanoparticles (<100 nm of tin, chromium and nickel. The concentrations of nine of eleven elements in EC aerosol were higher than or equal to the corresponding concentrations in conventional cigarette smoke. Many of the elements identified in EC aerosol are known to cause respiratory distress and disease.The presence of metal and silicate particles in cartomizer aerosol demonstrates the need for improved quality control in EC design and manufacture and studies on how EC aerosol impacts the health of users and bystanders.

  11. Potassium silicate and calcium silicate on the resistance of soybean to Phakopsora pachyrhizi infection

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Cruz

    2013-01-01

    Full Text Available The control of Asian Soybean Rust (ASR, caused by Phakopsora pachyrhizi, has been difficult due to the aggressiveness of the pathogen and the lack of resistant cultivars. The objective of this study was to evaluate the effects of spray of potassium silicate (PS and soil amendment with calcium silicate (CS on soybean resistance to ASR. The PS solution was sprayed to leaves 24 hours prior to fungal inoculation while CS was amended to the soil at thirty-five days before sowing. The infection process of P. pachyrhizi was investigated by scanning electron microscopy. The uredia on leaves of plants sprayed with PS were smaller and more compact than those observed on the leaves of plants grown in soil amended with CS or in soil non-amended with CS (control treatment. On leaves of plants from the control treatment, uredia produced many urediniospores at 9 days after inoculation, and the ASR severity was 15, 8 and 9%, respectively, for plants from control, PS and CS treatments. In conclusion, the spray of PS contributed to reduce the number of uredia per cm² of leaf area and both PS spray and CS resulted in lower ASR symptoms.

  12. 76 FR 23490 - Aluminum tris (O

    Science.gov (United States)

    2011-04-27

    ... AGENCY 40 CFR Part 180 Aluminum tris (O-ethylphosphonate), Butylate, Chlorethoxyfos, Clethodim, et al..., fosthiazate, propetamphos, and tebufenozide; the fungicide aluminum tris (O-ethylphosphonate); the herbicides.... Also, EPA is revoking the tolerances for aluminum tris (O-ethylphosphonate) on pineapple fodder...

  13. Guangxi Aluminum Giant Made Investment in Changfeng

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>A aluminum processing and supporting project (450,000 tons) of Hefei Guangyin Aluminum Company kicked off in Xiatang Town of Changfeng County recently. It is a project jointly invested by Guangxi Investment Group and Guangxi Baise Guangyin Aluminum in Xiatang Town of Changfeng County.

  14. Luminescent properties of aluminum hydride

    Energy Technology Data Exchange (ETDEWEB)

    Baraban, A.P.; Gabis, I.E.; Dmitriev, V.A. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Dobrotvorskii, M.A., E-mail: mstislavd@gmail.com [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Kuznetsov, V.G. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation); Matveeva, O.P. [National Mineral Resources University, Saint Petersburg 199106 (Russian Federation); Titov, S.A. [Petersburg State University of Railway Transport, Saint-Petersburg 190031 (Russian Federation); Voyt, A.P.; Elets, D.I. [Saint-Petersburg State University, Department of Physics, Saint-Petersburg 198504 (Russian Federation)

    2015-10-15

    We studied cathodoluminescence and photoluminescence of α-AlH{sub 3}– a likely candidate for use as possible hydrogen carrier in hydrogen-fueled vehicles. Luminescence properties of original α-AlH{sub 3} and α-AlH{sub 3} irradiated with ultraviolet were compared. The latter procedure leads to activation of thermal decomposition of α-AlH{sub 3} and thus has a practical implementation. We showed that the original and UV-modified aluminum hydride contain luminescence centers ‐ structural defects of the same type, presumably hydrogen vacancies, characterized by a single set of characteristic bands of radiation. The observed luminescence is the result of radiative intracenter relaxation of the luminescence center (hydrogen vacancy) excited by electrons or photons, and its intensity is defined by the concentration of vacancies, and the area of their possible excitation. UV-activation of the dehydrogenation process of aluminum hydride leads to changes in the spatial distribution of the luminescence centers. For short times of exposure their concentration increases mainly in the surface regions of the crystals. At high exposures, this process extends to the bulk of the aluminum hydride and ends with a decrease in concentration of luminescence centers in the surface region. - Highlights: • Aluminum hydride contains hydrogen vacancies which serve as luminescence centers. • The luminescence is the result of radiative relaxation of excited centers. • Hydride UV-irradiation alters distribution and concentration of luminescence centers.

  15. Aluminum break-point contacts

    NARCIS (Netherlands)

    Heinemann, Martina; Groot, R.A. de

    1997-01-01

    Ab initio molecular dynamics is used to study the contribution of a single Al atom to an aluminum breakpoint contact during the final stages of breaking and the initial stages of the formation of such a contact. A hysteresis effect is found in excellent agreement with experiment and the form of the

  16. COMPARISON OF SOL-GEL SILICATE COATINGS ON Ti SUBSTRATE

    Directory of Open Access Journals (Sweden)

    DIANA HORKAVCOVÁ

    2012-12-01

    Full Text Available The objective of the submitted work was to prepare and to characterize two types of silicate coatings prepared by the sol-gel method using the dip-coating technique on a titanium substrate. Efforts have been made to use mechanical properties of bio-inert titanium and bioactive properties of a silicate layer enriched with an admixture of compounds identified below. The first group consisted of silicate coatings containing silver, brushite and monetite. The other group of silicate coatings contained calcium nitrate and triethyl phosphate. Mechanically and chemically treated titanium substrates were dipped into sols and dried and fired. Silicate coatings from the first group were also chemically treated in 10 mol.l-1 solution of sodium hydroxide. All coatings were measured to determine their adhesive and bioactive properties and furthermore the antibacterial properties were tested in the case of first group. Surfaces of the coated substrates were investigated after the firing and after the individual tests with optical and electron microscopy and X-ray microdiffraction. A tape test demonstrated excellent adhesive property of all coatings to the substrate, classified with degree 5. A static in vitro test demonstrated bioactivity of nearly all the coatings. The basic silicate coating from the first group and one type of coating from the second group were identified as inert. Antibacterial properties of silicate coatings containing silver showed to be different when tested against Escherichia coli bacteria. A complete inhibition of the growth of bacteria under our experimental conditions was observed for the coating containing silver and monetite and a partial inhibition of the growth of bacteria for coatings containing silver and silver in combination with brushite.

  17. Silicic Arc Magmas And Silicic Slab Melts: The Melt-Rock Reaction Link

    Science.gov (United States)

    Straub, S. M.; Gomez-Tuena, A.; Bolge, L. L.; Espinasa-Perena, R.; Bindeman, I. N.; Stuart, F. M.; Zellmer, G. F.

    2013-12-01

    While a genetic link between silicic arc magmas and silicic melts from the subducted slab has long been proposed, this hypothesis is commonly refuted because most arc magmas lack a 'garnet-signature' which such slab melts must have. A comprehensive geochemical study of high-Mg# arc magmas from the Quaternary central Mexican Volcanic Belt (MVB), however, shows that this conflict can be reconciled if melt-rock reaction processes in the mantle wedge were essential to arc magma formation. In the central MVB, monogenetic and composite volcanoes erupt high-Mg# basalts to andesites with highly variable trace element patterns. These magmas contain high-Ni olivines (olivine Ni higher than permissible for olivines in partial peridotite melts) with high 3He/4He = 7-8 Ra that provide strong evidence for silicic slab components that infiltrate the subarc mantle to produce olivine-free segregations of 'reaction pyroxenite' in the sources of individual volcanoes. Melting of silica-excess and silica-deficient reaction pyroxenites can then produce high-Mg# basaltic and dacitic primary melts that mix during ascent through mantle and crust to form high-Mg# andesites. Mass balance requires that reaction pyroxenites contain at least >15-18 wt%, and likely more, of slab component. However, because the HREE of the slab component are efficiently retained in the eclogitic slab, elements Ho to Lu in partial melts from reaction pyroxenites remain controlled by the mantle and maintain MORB-normalized Ho/Lun ˜1.15 close to unity. In contrast, the MREE to LREE and fluid mobile LILE of the arc magmas are either controlled, or strongly influenced, by slab-contributions. The origin from hybrid sources also shows in the major elements that are blends of mantle-derived elements (Mg, Ca, Mn, Fe, Ti) and elements augmented by slab contributions (Si, Na, K, P, and possibly Al). Moreover, strong correlations between bulk rock SiO2, 87Sr/86Sr and δ18O (olivines) can be interpreted as mixtures of subarc

  18. Multilayer Clad Plate of Stainless Steel/Aluminum/Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    YUAN Jiawei; PANG Yuhua; LI Ting

    2011-01-01

    The 3, 5, 20 layer clad plate from austenitic stainless steel, pure aluminum and aluminum alloy sheets were fabricated in different ways. The stretch and interface properties were measured. The result shows that 20 layer clad plate is better than the others. Well-bonded clad plate was successfully obtained in the following procedure: Basic clad sheet from 18 layer A11060/A13003sheets was firstly obtained with an initial rolling reduction of 44% at 450 ℃, followed by annealing at 300 ℃, and then with reduction of 50% at 550 ℃ from STS304 on each side. The best 20 layer clad plate was of 129 MPa bonding strength and 225 MPa stretch strength.

  19. Electrodeposition of aluminum on aluminum surface from molten salt

    Institute of Scientific and Technical Information of China (English)

    Wenmao HUANG; Xiangyu XIA; Bin LIU; Yu LIU; Haowei WANG; Naiheng MA

    2011-01-01

    The surface morphology,microstructure and composition of the aluminum coating of the electrodeposition plates in AlC13-NaC1-KC1 molten salt with a mass ratio of 8:1:1 were investigated by SEM and EDS.The binding force was measured by splat-cooling method and bending method.The results indicate that the coatings with average thicknesses of 12 and 9 μm for both plates treated by simple grinding and phosphating are compacted,continuous and well adhered respectively. Tetramethylammonium chloride (TMAC) can effectively prevent the growth of dendritic crystal,and the anode activation may improve the adhesion of the coating. Binding force analysis shows that both aluminum coatings are strongly adhered to the substrates.

  20. Silicate Dust in Evolved Protoplanetary Disks: Growth, Sedimentation, and Accretion

    CERN Document Server

    Sicilia-Aguilar, Aurora; Watson, Dan; Bohac, Chris; Henning, Thomas; Bouwman, Jeroen; 10.1086/512121

    2009-01-01

    We present the Spitzer IRS spectra for 33 young stars in Tr 37 and NGC 7160. The sample includes the high- and intermediate-mass stars with MIPS 24 microns excess, the only known active accretor in the 12 Myr-old cluster NGC 7160, and 19 low-mass stars with disks in the 4 Myr-old cluster Tr 37. We examine the 10 microns silicate feature, present in the whole sample of low-mass star and in 3 of the high- and intermediate-mass targets, and we find that PAH emission is detectable only in the Herbig Be star. We analyze the composition and size of the warm photospheric silicate grains by fitting the 10 microns silicate feature, and study the possible correlations between the silicate characteristics and the stellar and disk properties (age, SED slope, accretion rate, spectral type). We find indications of dust settling with age and of the effect of turbulent enrichment of the disk atmosphere with large grains. Crystalline grains are only small contributors to the total silicate mass in all disks, and do not seem t...

  1. Heterogeneous nucleation of protein crystals on fluorinated layered silicate.

    Directory of Open Access Journals (Sweden)

    Keita Ino

    Full Text Available Here, we describe an improved system for protein crystallization based on heterogeneous nucleation using fluorinated layered silicate. In addition, we also investigated the mechanism of nucleation on the silicate surface. Crystallization of lysozyme using silicates with different chemical compositions indicated that fluorosilicates promoted nucleation whereas the silicates without fluorine did not. The use of synthesized saponites for lysozyme crystallization confirmed that the substitution of hydroxyl groups contained in the lamellae structure for fluorine atoms is responsible for the nucleation-inducing property of the nucleant. Crystallization of twelve proteins with a wide range of pI values revealed that the nucleation promoting effect of the saponites tended to increase with increased substitution rate. Furthermore, the saponite with the highest fluorine content promoted nucleation in all the test proteins regardless of their overall net charge. Adsorption experiments of proteins on the saponites confirmed that the density of adsorbed molecules increased according to the substitution rate, thereby explaining the heterogeneous nucleation on the silicate surface.

  2. Modeling dissolution in aluminum alloys

    Science.gov (United States)

    Durbin, Tracie Lee

    2005-07-01

    Aluminum and its alloys are used in many aspects of modern life, from soda cans and household foil to the automobiles and aircraft in which we travel. Aluminum alloy systems are characterized by good workability that enables these alloys to be economically rolled, extruded, or forged into useful shapes. Mechanical properties such as strength are altered significantly with cold working, annealing, precipitation-hardening, and/or heat-treatments. Heat-treatable aluminum alloys contain one or more soluble constituents such as copper, lithium, magnesium, silicon and zinc that individually, or with other elements, can form phases that strengthen the alloy. Microstructure development is highly dependent on all of the processing steps the alloy experiences. Ultimately, the macroscopic properties of the alloy depend strongly on the microstructure. Therefore, a quantitative understanding of the microstructural changes that occur during thermal and mechanical processing is fundamental to predicting alloy properties. In particular, the microstructure becomes more homogeneous and secondary phases are dissolved during thermal treatments. Robust physical models for the kinetics of particle dissolution are necessary to predict the most efficient thermal treatment. A general dissolution model for multi-component alloys has been developed using the front-tracking method to study the dissolution of precipitates in an aluminum alloy matrix. This technique is applicable to any alloy system, provided thermodynamic and diffusion data are available. Treatment of the precipitate interface is explored using two techniques: the immersed-boundary method and a new technique, termed here the "sharp-interface" method. The sharp-interface technique is based on a variation of the ghost fluid method and eliminates the need for corrective source terms in the characteristic equations. In addition, the sharp-interface method is shown to predict the dissolution behavior of precipitates in aluminum

  3. Functional substitution of coordination polyhedron in crystal structure of silicates

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    On the bases of the study of comparative crystal chemistry of silicates it has been concluded that the octahedra and square pyramids of Ti-O and Zr-O play functional role of tetrahedra of Si-O in the construction of crystal structures.Therefore,those silicates may be named titano- and zircono-silicates.Because of the functional similarity of coordination polyhedra,the structures of cristobalite and feldspar have been compared with those of perovskite and garnet,respectively.As a new concept,the functional replacement of tetrahedra by octahedra and/or pyramids is defined by the authors of this paper for favorable comparison of relative crystal structures.

  4. Calcined sodium silicate as solid base catalyst for biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Feng; Peng, Zhen-Gang; Dai, Jian-Ying; Xiu, Zhi-Long [Department of Bioscience and Biotechnology, School of Environmental and Biological Science and Technology, Dalian University of Technology, Dalian 116024 (China)

    2010-03-15

    This paper examined the use of calcined sodium silicate as a novel solid base catalyst in the transesterification of soybean oil with methanol. The calcined sodium silicate was characterized by DTA-TG, Hammett indicator method, XRD, SEM, BET, IR and FT-IR. It catalyzed the transesterification of soybean oil to biodiesel with a yield of almost 100% under the following conditions: sodium silicate of 3.0 wt.%, a molar ratio of methanol/oil of 7.5:1, reaction time of 60 min, reaction temperature of 60 C, and stirring rate of 250 rpm. The oil containing 4.0 wt.% water or 2.5 wt.% FFA could also be transesterified by using this catalyst. The catalyst can be reused for at least 5 cycles without loss of activity. (author)

  5. Electric field-induced softening of alkali silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    McLaren, C.; Heffner, W.; Jain, H. [Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015 (United States); Tessarollo, R.; Raj, R. [Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, Colorado 80309 (United States)

    2015-11-02

    Motivated by the advantages of two-electrode flash sintering over normal sintering, we have investigated the effect of an external electric field on the viscosity of glass. The results show remarkable electric field-induced softening (EFIS), as application of DC field significantly lowers the softening temperature of glass. To establish the origin of EFIS, the effect is compared for single vs. mixed-alkali silicate glasses with fixed mole percentage of the alkali ions such that the mobility of alkali ions is greatly reduced while the basic network structure does not change much. The sodium silicate and lithium-sodium mixed alkali silicate glasses were tested mechanically in situ under compression in external electric field ranging from 0 to 250 V/cm in specially designed equipment. A comparison of data for different compositions indicates a complex mechanical response, which is observed as field-induced viscous flow due to a combination of Joule heating, electrolysis and dielectric breakdown.

  6. Effect of Minor Elements on Silicate Cement Clinker

    Institute of Scientific and Technical Information of China (English)

    HUANG Congyun; ZHANG Mingfei; ZHANG Meixiang; LONG Shizong; CHEN Yuankui; MA Baoguo

    2005-01-01

    The effect of rare-earth and HX addition agent on the burn-ability of silicate cement clinker was investigated by orthogonal experiment. The result shows, compared with blank sample, f- CaO of the samples added with rare-earth and HX agent drops by 84.95% , its 3d and 28d compressive strength enhances by 24.40%and 16.90%, respectively. It was discovered by means of X-ray diffraction and high temperature microscope analysis that sintering temperature of the sample added with rare-earth and HX addition agent is about 1320℃. At the same time, the burning temperature of tricalcium silicate desends and its crystal growth forming-rate increases.Tricalcium silicate content in burning clinker is higher and its crystal is larger.

  7. Rubber curing chemistry governing the orientation of layered silicate

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available The effect of curing systems on the orientation and the dispersion of the layered silicates in acrylonitrile butadiene rubber nanocomposite is reported. Significant differences in X-ray diffraction pattern between peroxide curing and sulfur curing was observed. Intense X-ray scattering values in the XRD experiments from peroxide cured vulcanizates indicate an orientation of the layers in a preferred direction as evinced by transmission electron micrographs. However, sulfur cured vulcanizates show no preferential orientation of the silicate particles. Nevertheless, a closer inspection of transmission electron microscopy (TEM images of peroxide and sulfur cured samples shows exfoliated silicate layers in the acrylonitrile butadiene rubber (NBR matrix. It was revealed in the prevailing study that the use of an excess amount of stearic acid in the formulation of the sulfur curing package leads to almost exfoliated type X-ray scattering pattern.

  8. Structural chemistry of anhydrous sodium silicates - a review.

    Science.gov (United States)

    Kahlenberg, Volker

    2010-01-01

    Sodium silicates are of considerable importance for many fields of inorganic chemistry and applied mineralogy, being either raw materials for synthesis or already finished products. In addition to their industrial relevance they have also been studied intensively because of their interesting physico-chemical properties including high ion-exchange capacity and selectivity or two-dimensional sodium diffusion and conductivity. Furthermore, the structural chemistry of crystalline sodium silicates offers the crystallographer challenging tasks such as polytypism, polymorphism, temperature and/or pressure-dependent phase transitions, pseudo-symmetry, complex twinning phenomena as well as incommensurately modulated structures. Many of these structural problems have been solved only recently, although in some cases they have been known for several decades. This article will provide an overview on the structurally characterized sodium silicates and their fascinating crystallochemical characteristics.

  9. Behaviour of Silicate Melts in Respect of Volume

    Institute of Scientific and Technical Information of China (English)

    张金民; 叶大年

    1989-01-01

    The volumes per oxygen of some silicate melts have been calculated and then compared with those of silicate glasses.It is suggested that the volume of a silicate melt can be divided into two parts.One is contri buted by the silicon-oxygen network and the other by the “oxides”.Variation patterns of VPOs suggest that the volume of the Si-O network generally remains unchanged and the expansion of the melt is caused mainly by the locat expansion of the “oxides”.It is further proposed that the radius of O2- shows little variation,in striking contrast to the radius of cations.The mechanism governing the expansion is discussed in detail.

  10. Energetic Processing of Interstellar Silicate Grains by Cosmic Rays

    Energy Technology Data Exchange (ETDEWEB)

    Bringa, E M; Kucheyev, S O; Loeffler, M J; Baragiola, R A; Tielens, A G Q M; Dai, Z R; Graham, G; Bajt, S; Bradley, J; Dukes, C A; Felter, T E; Torres, D F; van Breugel, W

    2007-03-28

    While a significant fraction of silicate dust in stellar winds has a crystalline structure, in the interstellar medium nearly all of it is amorphous. One possible explanation for this observation is the amorphization of crystalline silicates by relatively 'low' energy, heavy ion cosmic rays. Here we present the results of multiple laboratory experiments showing that single-crystal synthetic forsterite (Mg{sub 2}SiO{sub 4}) amorphizes when irradiated by 10 MeV Xe{sup ++} ions at large enough fluences. Using modeling, we extrapolate these results to show that 0.1-5.0 GeV heavy ion cosmic rays can rapidly ({approx}70 Million yrs) amorphize crystalline silicate grains ejected by stars into the interstellar medium.

  11. Diffusion-bonded beryllium aluminum optical structures

    Science.gov (United States)

    Grapes, Thomas F.

    2003-12-01

    Beryllium aluminum material can present significant advantages for optical support structures. A likely advantage of beryllium aluminum compared to aluminum or titanium for such structures is its higher specific stiffness. However, beryllium aluminum material is significantly more expensive than most competing materials. The cost problem with beryllium aluminum is exacerbated if fabrication methods that result in near net shape parts are not used. Near net shape methods result in the least amount of material "thrown away" in the fabrication process. Casting is a primary example of near net shape manufacturing that is appropriate for some optical support structures. Casting aluminum, and other materials as well, is common. Casting of beryllium aluminum is very difficult, however, and has not had significant success. Diffusion bonding - a different approach for achieving near net shape beryllium aluminum optical support structures, was pursued and accomplished. Diffusion bonding is a term used to describe the joining of solid metal pieces under high temperature and pressure, but without melting. Three different optical support structures were designed and built of beryllium aluminum using diffusion bonding. Relatively small solid beryllium aluminum pieces were arranged together and then joined under hot isostatic pressure conditions. The resulting relatively large pressure bonded part was then machined to achieve the final product. Significant cost savings as compared to machining the part from a solid block were realized. Difficulties achieving diffusion bonds in complex joints were experienced and addressed.

  12. Potassium Silicate Foliar Fertilizer Grade from Geothermal Sludge and Pyrophyllite

    Directory of Open Access Journals (Sweden)

    Muljani Srie

    2016-01-01

    Full Text Available Potassium silicate fertilizer grade were successfully produced by direct fusion of silica (SiO2 and potasium (KOH and K2CO3 in furnaces at temperatures up to melting point of mixture. The geothermal sludge (98% SiO2 and the pyrophyllite (95% SiO2 were used as silica sources. The purposes of the study was to synthesise potassium silicate fertilizer grade having solids concentrations in the range of 31-37% K2O, and silica in the range of 48-54% SiO2. The weight ratio of silicon dioxide/potasium solid being 1:1 to 5:1. Silica from geothermal sludge is amorphous, whereas pyrophylite is crystalline phase. The results showed that the amount of raw materials needed to get the appropriate molar ratio of potassium silicate fertilizer grade are different, as well as the fusion temperature of the furnace. Potassium silicate prepared from potassium hydroxide and geothermal sludge produced a low molar ratio (2.5: 1 to 3: 1. The potassium required quite small (4:1 in weight ratio, and on a fusion temperature of about 900 °C. Meanwhile, the potassium silicate prepared from pyrophyllite produced a high molar ratio (1.4 - 9.4 and on a fusion temperature of about 1350 °C, so that potassium needed large enough to meet the required molar ratio for the fertilizer grade. The product potassium silicate solid is amorphous with a little trace of crystalline.

  13. Nitrogen distribution between aqueous fluids and silicate melts

    Science.gov (United States)

    Li, Yuan; Huang, Ruifang; Wiedenbeck, Michael; Keppler, Hans

    2015-02-01

    The partitioning of nitrogen between hydrous fluids and haplogranitic, basaltic, or albitic melts was studied at 1-15 kbar, 800-1200 °C, and oxygen fugacities (fO2) ranging from the Fe-FeO buffer to 3log units above the Ni-NiO buffer. The nitrogen contents in quenched glasses were analyzed either by electron microprobe or by secondary ion mass spectrometry (SIMS), whereas the nitrogen contents in fluids were determined by mass balance. The results show that the nitrogen content in silicate melt increases with increasing nitrogen content in the coexisting fluid at given temperature, pressure, and fO2. Raman spectra of the silicate glasses suggest that nitrogen species change from molecular N2 in oxidized silicate melt to molecular ammonia (NH3) or the ammonium ion (NH4+) in reduced silicate melt, and the normalized Raman band intensities of the nitrogen species linearly correlate with the measured nitrogen content in silicate melt. Elevated nitrogen contents in silicate melts are observed at reduced conditions and are attributed to the dissolution of NH3/NH4+. Measured fluid/melt partition coefficients for nitrogen (DNfluid/ melt) range from 60 for reduced haplogranitic melts to about 10 000 for oxidized basaltic melts, with fO2 and to a lesser extent melt composition being the most important parameters controlling the partitioning of nitrogen. Pressure appears to have only a minor effect on DNfluid/ melt in the range of conditions studied. Our data imply that degassing of nitrogen from both mid-ocean ridge basalts and arc magmas is very efficient, and predicted nitrogen abundances in volcanic gases match well with observations. Our data also confirm that nitrogen degassing at present magma production rates is insufficient to accumulate the atmosphere. Most of the nitrogen in the atmosphere must have degassed very early in Earth's history and degassing was probably enhanced by the oxidation of the mantle.

  14. Aluminum/air electrochemical cells

    OpenAIRE

    Wang, Lei; 王雷

    2014-01-01

    Aluminum (Al) is a very promising energy carrier given its high capacity and energy density, low cost, earth abundance and environmental benignity. The Al/air battery as a kind of metal/air electrochemical cell attracts tremendous attention. Traditional Al/air batteries suffer from the self-corrosion and related safety problems. In this work, three new approaches were investigated to tackle these challenges and to develop high-performance Al/air cells: (1) incorporate an additional hydrogen/a...

  15. Electrically Conductive Anodized Aluminum Surfaces

    Science.gov (United States)

    Nguyen, Trung Hung

    2006-01-01

    Anodized aluminum components can be treated to make them sufficiently electrically conductive to suppress discharges of static electricity. The treatment was conceived as a means of preventing static electric discharges on exterior satin-anodized aluminum (SAA) surfaces of spacecraft without adversely affecting the thermal-control/optical properties of the SAA and without need to apply electrically conductive paints, which eventually peel off in the harsh environment of outer space. The treatment can also be used to impart electrical conductivity to anodized housings of computers, medical electronic instruments, telephoneexchange equipment, and other terrestrial electronic equipment vulnerable to electrostatic discharge. The electrical resistivity of a typical anodized aluminum surface layer lies between 10(exp 11) and 10(exp 13) Omega-cm. To suppress electrostatic discharge, it is necessary to reduce the electrical resistivity significantly - preferably to anodized surface becomes covered and the pores in the surface filled with a transparent, electrically conductive metal oxide nanocomposite. Filling the pores with the nanocomposite reduces the transverse electrical resistivity and, in the original intended outer-space application, the exterior covering portion of the nanocomposite would afford the requisite electrical contact with the outer-space plasma. The electrical resistivity of the nanocomposite can be tailored to a value between 10(exp 7) and 10(exp 12) Omega-cm. Unlike electrically conductive paint, the nanocomposite becomes an integral part of the anodized aluminum substrate, without need for adhesive bonding material and without risk of subsequent peeling. The electrodeposition process is compatible with commercial anodizing production lines. At present, the electronics industry uses expensive, exotic, electrostaticdischarge- suppressing finishes: examples include silver impregnated anodized, black electroless nickel, black chrome, and black copper. In

  16. Purification technology of molten aluminum

    Institute of Scientific and Technical Information of China (English)

    孙宝德; 丁文江; 疏达; 周尧和

    2004-01-01

    Various purification methods were explored to eliminate the dissolved hydrogen and nonmetallic inclusions from molten aluminum alloys. A novel rotating impeller head with self-oscillation nozzles or an electromagnetic valve in the gas circuit was used to produce pulse gas currents for the rotary impeller degassing method. Water simulation results show that the size of gas bubbles can be decreased by 10%-20% as compared with the constant gas current mode. By coating ceramic filters or particles with active flux or enamels, composite filters were used to filter the scrap A356 alloy and pure aluminum. Experimental results demonstrate that better filtration efficiency and operation performance can be obtained. Based on numerical calculations, the separation efficiency of inclusions by high frequency magnetic field can be significantly improved by using a hollow cylinder-like separator or utilizing the effects of secondary flow of the melt in a square separator. A multi-stage and multi-media purification platform based on these methods was designed and applied in on-line processing of molten aluminum alloys. Mechanical properties of the processed scrap A356 alloy are greatly improved by the composite purification.

  17. Electrical conductivity measurements on silicate melts using the loop technique

    Science.gov (United States)

    Waff, H. S.

    1976-01-01

    A new method is described for measurement of the electrical conductivity of silicate melts under controlled oxygen partial pressure at temperatures to 1550 C. The melt samples are suspended as droplets on platinum-rhodium loops, minimizing iron loss from the melt due to alloying with platinum, and providing maximum surface exposure of the melt to the oxygen-buffering gas atmosphere. The latter provides extremely rapid equilibration of the melt with the imposed oxygen partial pressure. The loop technique involves a minimum of setup time and cost, provides reproducible results to within + or - 5% and is well suited to electrical conductivity studies on silicate melts containing redox cations.

  18. Mathematical Viscosity Models for Ternary Metallic and Silicate Melts

    Institute of Scientific and Technical Information of China (English)

    FU Yuan-kun; MENG Xian-min; GUO Han-jie

    2004-01-01

    The mathematical viscosity models for metallic melts were discussed. The experimental data of Ag-Au-Cu systems were used to verify the models based on Chou's general geometric thermodynamic model and the calculated results are consistent with the reported experimental data. A new model predicting the viscosity of multi-component silicate melts was established. The CaO-MnO-SiO2, CaO-FeO-SiO2 and FeO-MnO-SiO2 silicate slag systems were used to verify the model.

  19. Leaf application of silicic acid to upland rice and corn

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Costa Crusciol

    2013-12-01

    Full Text Available This study aimed to evaluate the effect of Si (stabilized silicic acid, Silamol® leaf application on mineral nutrition and yield in upland rice and corn crops. The treatments were the control (without Si and Si foliar split spraying using 2 L ha-1 of the Silamol® commercial product, with 0.8% soluble Si as concentrated stabilized silicic acid. Silicon leaf application increased the concentrations of K, Ca and Si in rice and corn leaves, the number of panicles per m2 of rice and the number of grains per ear of corn; accordingly, the Si leaf application provided a higher grain yield in both crops.

  20. Discovery of ancient silicate stardust in a meteorite.

    Science.gov (United States)

    Nguyen, Ann N; Zinner, Ernst

    2004-03-05

    We have discovered nine presolar silicate grains from the carbonaceous chondrite Acfer 094. Their anomalous oxygen isotopic compositions indicate formation in the atmospheres of evolved stars. Two grains are identified as pyroxene, two as olivine, one as a glass with embedded metal and sulfides (GEMS), and one as an Al-rich silicate. One grain is enriched in 26Mg, which is attributed to the radioactive decay of 26Al and provides information about mixing processes in the parent star. This discovery opens new means for studying stellar processes and conditions in various solar system environments.

  1. Mbosi: An anomalous iron with unique silicate inclusions

    Science.gov (United States)

    Olsen, Edward J.; Clayton, Robert N.; Mayeda, Toshiko K.; Davis, Andrew M.; Clarke, Roy S., Jr.; Wasson, John T.

    1996-09-01

    The Mbosi iron meteorite contains millimeter size silicate inclusions. Mbosi is an ungrouped iron meteorite with a Ge/Ga ratio >10, which is an anomalous property shared with the five-member IIF iron group, the Eagle Station pallasites and four other ungrouped irons. Neither the IIF group nor the four other ungrouped irons are known to have silicate inclusions. Chips from three Mbosi inclusions were studied, but most of the work concentrated on a whole 3.1 mm circular inclusion. This inclusion consists of a mantle and a central core of different mineralogies. The mantle is partially devitrified quartz-normative glass, consisting of microscopic crystallites of two pyroxenes and plagioclase, which are crystalline enough to give an x-ray powder diffraction pattern but not coarse enough to permit analyses of individual minerals. The core consists of silica. The bulk composition does not match any known meteorite type, although there is a similarity in mode of occurrence to quartz-normative silicate inclusions in some HE irons. Mbosi silicate appears to be unique. The bulk rare earth element (REE) pattern of the mantle is flat at ≅ 7×C1; the core is depleted in REE but shows a small positive Eu anomaly. The O-isotope composition of bulk silicate lies on a unit slope mixing line (parallel and close to the C3 mixing line) that includes the Eagle Station pallasites and the iron Bocaiuva (related to the IIF irons); all of these share the property of having Ge/Ga ratios >10. It is concluded that Mbosi silicate represents a silica-bearing source rock that was melted and injected into metal. Melting occurred early in the history of the parent body because the metal now shows a normal Widmanstätten structure with only minor distortion that was caused when the parent body broke up and released meteorites into interplanetary space. The cause of Ge/Ga ratios being >10 in these irons is unknown. The fact that silicates in Mbosi, Bocaiuva (related to IIF irons) and the Eagle

  2. Thermal Expansion and Thermal Conductivity of Rare Earth Silicates

    Science.gov (United States)

    Zhu, Dongming; Lee, Kang N.; Bansal, Narottam P.

    2006-01-01

    Rare earth silicates are considered promising candidate materials for environmental barrier coatings applications at elevated temperature for ceramic matrix composites. High temperature thermophysical properties are of great importance for coating system design and development. In this study, the thermal expansion and thermal conductivity of hot-pressed rare earth silicate materials were characterized at temperatures up to 1400 C. The effects of specimen porosity, composition and microstructure on the properties were also investigated. The materials processing and testing issues affecting the measurements will also be discussed.

  3. Core Formation Timescale, Silicate-Metal Equilibration, and W Diffusivity

    Science.gov (United States)

    Yin, Q.; Jacobsen, B.; Tinker, D.; Lesher, C.

    2004-12-01

    The extent to which material accreted to the proto-Earth and segregated to form the core was chemically and isotopically equilibrated with the silicate mantle is an outstanding problem in planetary science. This is particularly important when attempting to assign a meaningful age for planetary accretion and core formation based on Hf-W isotope systematics. The Earth and other terrestrial planets likely formed by accretion of previously differentiated planetesimals. For the planetesimals themselves the most important energy source for metal-silicate differentiation is the combined radioactive heating due to decay of 26Al (half-life 0.7 Ma) and 60Fe (half-life 1.5 Ma). It is expected that the fractionation of Hf and W during planetesimal core formation will lead to a divergence in the W isotopic compositions of the core and silicate portions of these bodies. This expectation is supported by the enormously radiogenic 182W signatures reported for basaltic eucrites. The observation that the W isotopic compositions of the silicate portions of Earth, Moon and Mars are similar and markedly less radiogenic than eucrites suggests that during planet accretion the pre-differentiated metallic core material containing low 182W must have equilibrated extensively with the more radiogenic (high 182W) silicate material to subdue the ingrowth of 182W in the silicate mantle of the planets. The standard theory of planet formation predicts that after runaway and oligarchic growth, the late stage of planet formation is characterized by impact and merging of Mars-sized objects. This is a tremendously energetic process estimated to raise the temperature of the proto-Earth to about 7000K (a temperature equivalent to a mass spectrometer's plasma source, which indiscriminately ionizes all incoming elements). After the giant impacts, the proto-Earth had a luminosity and surface temperature close to a low mass star for a brief period of time. Stevenson (1990) argued that emulsification caused

  4. COMPARATIVE ANALYSIS OF STEEL AND ALUMINUM STRUCTURES

    Directory of Open Access Journals (Sweden)

    Josip Peko

    2016-12-01

    Full Text Available This study examined steel and aluminum variants of modern exhibition structures in which the main design requirements include low weight (increased span/depth ratio, transportation, and construction and durability (resistance to corrosion. This included a design situation in which the structural application of aluminum alloys provided an extremely convenient and practical solution. Viability of an aluminum structure depends on several factors and requires a detailed analysis. The overall conclusion of the study indicated that aluminum can be used as a structural material and as a viable alternative to steel for Croatian snow and wind load values and evidently in cases in which positive properties of aluminum are required for structural design. Furthermore, a structural fire analysis was conducted for an aluminum variant structure by using a zone model for realistic fire analysis. The results suggested that passive fire protection for the main structural members was not required in the event of areal fire with duration of 60 min.

  5. [Link between aluminum neurotoxicity and neurodegenerative disorders].

    Science.gov (United States)

    Kawahara, Masahiro

    2016-07-01

    Aluminum is an old element that has been known for a long time, but some of its properties are only now being discovered. Although environmentally abundant, aluminum is not essential for life; in fact, because of its specific chemical properties, aluminum inhibits more than 200 biologically important functions and exerts various adverse effects in plants, animals, and humans. Aluminum is a widely recognized neurotoxin. It has been suggested that there is a relationship between exposure to aluminum and neurodegenerative diseases, including dialysis encephalopathy, amyotrophic lateral sclerosis and parkinsonism dementia in the Kii Peninsula and Guam, as well as Alzheimer' s disease: however, this claim remains to be verified. In this chapter, we review the detailed characteristics of aluminum neurotoxicity and the link between Alzheimer' s disease and other neurodegenerative diseases, based on recent findings on metal-metal interactions and the functions of metalloproteins in synapses.

  6. Optical Transmittance of Anodically Oxidized Aluminum Alloy

    Science.gov (United States)

    Saito, Mitsunori; Shiga, Yasunori; Miyagi, Mitsunobu; Wada, Kenji; Ono, Sachiko

    1995-06-01

    Optical transmittance and anisotropy of anodic oxide films that were made from pure aluminum and an aluminum alloy (A5052) were studied. The alloy oxide film exhibits an enhanced polarization function, particularly when anodization is carried out at a large current density. It was revealed by chemical analysis that the alloy oxide film contains a larger amount of unoxidized aluminum than the pure-aluminum oxide film. The polarization function can be elucidated by considering unoxidized aluminum particles that are arranged in the columnar structure of the alumina film. Electron microscope observation showed that many holes exist in the alloy oxide film, around which columnar cells are arranged irregularly. Such holes and irregular cell arrangement cause the increase in the amount of unoxidized aluminum, and consequently induces scattering loss.

  7. Craters in aluminum 1100 targets using glass projectiles at 1-7 km/s

    Science.gov (United States)

    Bernhard, R. P.; See, T. H.; Hoerz, F.; Cintala, M. J.

    1994-01-01

    We report on impact experiments using soda-lime glass spheres of 3.2 mm diameter and aluminum targets (1100 series). The purpose is to assist in the interpretation of LDEF instruments and in the development of future cosmic-dust collectors in low-Earth orbit. Because such instruments demand understanding of both the cratering and penetration process, we typically employ targets with thicknesses that range from massive, infinite half-space targets, to ultrathin films. This report addresses a subset of cratering experiments that were conducted to fine-tune our understanding of crater morphology as a function of impact velocity. Also, little empirical insight exists about the physical distribution and shock-metamorphism of the impactor residues as a function of encounter speed, despite their recognized significance in the analysis of space-exposed surfaces. Soda-lime glass spheres were chosen as a reasonable analog to extraterrestrial silicates, and aluminum 1100 was chosen for targets, which among the common Al-alloys, best represents the physical properties of high-purity aluminum. These materials complement existing impact studies that typically employed metallic impactors and less ductile Al-alloys. We have completed dimensional analyses of the resulting craters and are in the process of investigating the detailed distribution of the unmelted and melted impactor residues via SEM methods, as well as potential compositional modifications of the projectile melts via electron microprobe.

  8. Structure of Liquid Aluminum and Hydrogen Absorption

    Institute of Scientific and Technical Information of China (English)

    LIU Yang; DAI Yongbing; WANG Jun; SHU Da; SUN Baode

    2011-01-01

    The hydrogen content in aluminum melts at different temperature was detected. The structure in aluminum melts was investigated by molecular dynamics simulation. The first peak position of pair correlation function, atomic coordination number and viscosity of aluminum melts were calculated and they changed abnormally in the same temperature range. The mechanism of hydrogen absorption has been discussed. From molecular dynamics calculations, the interdependence between melt structural properties and hydrogen absorption were obtained.

  9. Non-conservative controls on distribution of dissolved silicate in Cochin Backwaters

    Digital Repository Service at National Institute of Oceanography (India)

    Balachandran, K.K.; Sankaranarayanan, V.N.; Joseph, T.; Nair, M.

    Cochin backwater system was studied with regard to dissolved silicate (DSi) to understand its seasonal distribution and behaviour during estuarine mixing. Silicate had a linear relationship with salinity during the high river discharge period...

  10. Aluminum-stabilized NB3SN superconductor

    Science.gov (United States)

    Scanlan, Ronald M.

    1988-01-01

    An aluminum-stabilized Nb.sub.3 Sn superconductor and process for producing same, utilizing ultrapure aluminum. Ductile components are co-drawn with aluminum to produce a conductor suitable for winding magnets. After winding, the conductor is heated to convert it to the brittle Nb.sub.3 Sn superconductor phase, using a temperature high enough to perform the transformation but still below the melting point of the aluminum. This results in reaction of substantially all of the niobium, while providing stabilization and react-in-place features which are beneficial in the fabrication of magnets utilizing superconducting materials.

  11. Preparation and Characterization of Amorphous Layer on Aluminum Alloy Formed by Plasma Electrolytic Deposition (PED)

    Institute of Scientific and Technical Information of China (English)

    GUANYong-jun; XIAYuan

    2004-01-01

    In this investigation, protective layers were formed on aluminum substrate by Plasma Electrolytic Deposition (PED) using sodium silicate solution. The relation between the thickness of the layer and process time were studied. XRD, SEM, EDS were used to study the layer's structure, composition and micrograph. The results show that the deposited layers are amorphous and contain mainly oxygen, silicon, and aluminum. The possible formation mechanism of amorphous[Al-Si-O] layer was proposed: During discharge periods, Al2O3 phase of the passive film and SiO32- near the substrate surface are sintered into xSiO2(1-x)Al2O3 and then transformed into amorphous [Al-Si-O] phase.

  12. Energetics of silicate melts from thermal diffusion studies

    Energy Technology Data Exchange (ETDEWEB)

    Walker, D.

    1992-07-01

    Efforts are reported in the following areas: laboratory equipment (multianvils for high P/T work, pressure media, SERC/DL sychrotron), liquid-state thermal diffusion (silicate liquids, O isotopic fractionation, volatiles, tektites, polymetallic sulfide liquids, carbonate liquids, aqueous sulfate solutions), and liquid-state isothermal diffusion (self-diffusion, basalt-rhyolite interdiffusion, selective contamination, chemical diffusion).

  13. Estimation of high temperature metal-silicate partition coefficients

    Science.gov (United States)

    Jones, John H.; Capobianco, Christopher J.; Drake, Michael J.

    1992-01-01

    It has been known for some time that abundances of siderophile elements in the upper mantle of the Earth are far in excess of those expected from equilibrium between metal and silicate at low pressures and temperatures. Murthy (1991) has re-examined this excess of siderophile element problem by estimating liquid metal/liquid silicate partition coefficients reduces from their measured values at a lower temperature, implying that siderophile elements become much less siderophilic at high temperatures. Murthy then draws the important conclusion that metal/silicate equilibrium at high temperatures can account for the abundances of siderophile elements in the Earth's mantle. Of course, his conclusion is critically dependent on the small values of the partition coefficients he calculates. Because the numerical values of most experimentally-determined partition coefficients increase with increasing temperature at both constant oxygen fugacity and at constant redox buffer, we think it is important to try an alternative extrapolation for comparison. We have computed high temperature metal/silicate partition coefficients under a different set of assumptions and show that such long temperature extrapolations yield values which are critically dependent upon the presumed chemical behavior of the siderophile elements in the system.

  14. Ubiquitous high-FeO silicates in enstatite chondrites

    Science.gov (United States)

    Lusby, David; Scott, Edward R. D.; Keil, Klaus

    1987-01-01

    SEM and EMPA were used to determine the mineral contents of four EH3 chondrites. All four showed the dominant enstatite peak, Fs 0-5, with 4-8 percent of FeO-rich pyroxene with Fs 5-20. Among the 542 objects found to contain high-FeO silicates, 18 were chondrules, 381 were rimmed or unrimmed grains, and 143 were aggregates. The high-FeO silicates in these objects are very largely pyroxene with Fs 5-23. Large grains of both FeO-rich and FeO-poor silicates were found to be present in the FeO-rich chondrules. This fact, together with the absence of clasts of FeO-rich chondritic material in the EH3 chondrites, suggests that FeO-rich grains were introduced before or during chondrule formation. It is concluded that FeO-rich and FeO-poor silicates were both present in the nebular region where E chondrites originated.

  15. On the Dissolution Behavior of Sulfur in Ternary Silicate Slags

    Science.gov (United States)

    Kang, Youn-Bae; Park, Joo Hyun

    2011-12-01

    Sulfur dissolution behavior, in terms of sulfide capacity ( C S), in ternary silicate slags (molten oxide slags composed of MO - NO - SiO2, where M and N are Ca, Mn, Fe, and Mg), is discussed based on available experimental data. Composition dependence of the sulfur dissolution, at least in the dilute region of sulfur, may be explained by taking into account the cation-anion first-nearest-neighbor (FNN) interaction (stability of sulfide) and the cation-cation second-nearest-neighbor (SNN) interaction over O anion (oxygen proportions in silicate slags). When the Gibbs energy of a reciprocal reaction MO + NS = MS + NO is positive, the sulfide capacity of slags with virtually no SiO2 or low SiO2 concentration decreases as the concentration of MO increases. However, in some slags, as SiO2 concentration increases, replacing NO by MO at a constant SiO2 concentration may increase sulfide capacity when the basicity of NO is less than that of MO. This phenomenon is observed as rotation of iso- C S lines in ternary silicate slags, and it is explained by simultaneous consideration of the stability of sulfide and oxygen proportions in the silicate slags. It is suggested that a solution model for the prediction of sulfide capacity should be based on the actual dissolution mechanism of sulfur rather than on the simple empirical correlation.

  16. Experiments on metal-silicate plumes and core formation.

    Science.gov (United States)

    Olson, Peter; Weeraratne, Dayanthie

    2008-11-28

    Short-lived isotope systematics, mantle siderophile abundances and the power requirements of the geodynamo favour an early and high-temperature core-formation process, in which metals concentrate and partially equilibrate with silicates in a deep magma ocean before descending to the core. We report results of laboratory experiments on liquid metal dynamics in a two-layer stratified viscous fluid, using sucrose solutions to represent the magma ocean and the crystalline, more primitive mantle and liquid gallium to represent the core-forming metals. Single gallium drop experiments and experiments on Rayleigh-Taylor instabilities with gallium layers and gallium mixtures produce metal diapirs that entrain the less viscous upper layer fluid and produce trailing plume conduits in the high-viscosity lower layer. Calculations indicate that viscous dissipation in metal-silicate plumes in the early Earth would result in a large initial core superheat. Our experiments suggest that metal-silicate mantle plumes facilitate high-pressure metal-silicate interaction and may later evolve into buoyant thermal plumes, connecting core formation to ancient hotspot activity on the Earth and possibly on other terrestrial planets.

  17. Nd3+ Doped Silicate Glass Photonic Crystal Fibres

    Institute of Scientific and Technical Information of China (English)

    YANG Lu-Yun; CHEN Dan-Ping; XIA Jin-An; WANG Chen; JIANG Xiong-Wei; ZHU Cong-Shan; QIU Jian-Rong

    2005-01-01

    @@ We report on the fabrication of two kinds of large core area Nd3+ doped silicate glass photonic crystal fibres, and demonstration of the fibre waveguiding properties. The measured minimum loss of one kind ofibres is 2.5 db/m at 660nm. The fibres sustain only a single mode at least over the wavelength range from 660nm to 980nm.

  18. Calorimetric signature of structural heterogeneity in a ternary silicate glass

    DEFF Research Database (Denmark)

    Zhang, Yanfei; Yang, G.; Yue, Yuanzheng

    2013-01-01

    We investigate the structural heterogeneity in a silicate glass by hyperquenching–annealing–calorimetry approach. The results show a striking phenomenon: two separated sub-Tg relaxation peaks appear on the calorimetric curve of the hyperquenched CaO–MgO–SiO2 glass, implying the existence of two d...

  19. Phase Diagrams of Silicate Systems: Handbook; Third Issue; Ternary Systems

    Science.gov (United States)

    In the third issue of the handbook Phase Diagrams of Silicate Systems, information is included on the phase relationships in systems containing...radioelectronics, nuclear engineering, etc. Not only are equilibrium phase diagrams presented in the handbook, but the phases existing in the

  20. Electron stimulated hydroxylation of a metal supported silicate film.

    Science.gov (United States)

    Yu, Xin; Emmez, Emre; Pan, Qiushi; Yang, Bing; Pomp, Sascha; Kaden, William E; Sterrer, Martin; Shaikhutdinov, Shamil; Freund, Hans-Joachim; Goikoetxea, Itziar; Wlodarczyk, Radoslaw; Sauer, Joachim

    2016-02-01

    Water adsorption on a double-layer silicate film was studied by using infrared reflection-absorption spectroscopy, thermal desorption spectroscopy and scanning tunneling microscopy. Under vacuum conditions, small amounts of silanols (Si-OH) could only be formed upon deposition of an ice-like (amorphous solid water, ASW) film and subsequent heating to room temperature. Silanol coverage is considerably enhanced by low-energy electron irradiation of an ASW pre-covered silicate film. The degree of hydroxylation can be tuned by the irradiation parameters (beam energy, exposure) and the ASW film thickness. The results are consistent with a generally accepted picture that hydroxylation occurs through hydrolysis of siloxane (Si-O-Si) bonds in the silica network. Calculations using density functional theory show that this may happen on Si-O-Si bonds, which are either parallel (i.e., in the topmost silicate layer) or vertical to the film surface (i.e., connecting two silicate layers). In the latter case, the mechanism may additionally involve the reaction with a metal support underneath. The observed vibrational spectra are dominated by terminal silanol groups (ν(OD) band at 2763 cm(-1)) formed by hydrolysis of vertical Si-O-Si linkages. Film dehydroxylation fully occurs only upon heating to very high temperatures (∼ 1200 K) and is accompanied by substantial film restructuring, and even film dewetting upon cycling hydroxylation/dehydroxylation treatment.

  1. Silicate Dispersion and Mechanical Reinforcement in Polysiloxane/Layered Silicate Nanocomposites

    KAUST Repository

    Schmidt, Daniel F.

    2010-01-12

    We report the first in-depth comparison of the mechanical properties and equilibrium solvent uptake of a range of polysiloxane nanocomposites based on treated and untreated montmorillonite and fumed silica nanofillers. We demonstrate the ability of equilibrium solvent uptake data (and, thus, overall physical and chemical cross-link density) to serve as a proxy for modulus (combining rubber elasticity and Flory-Rehner theory), hardness (via the theory of Boussinesq), and elongation at break, despite the nonideal nature of these networks. In contrast, we find that tensile and tear strength are not well-correlated with solvent uptake. Interfacial strength seems to dominate equilibrium solvent uptake and the mechanical properties it predicts. In the montmorillonite systems in particular, this results in the surprising consequence that equilibrium solvent uptake and mechanical properties are independent of dispersion state. We conclude that edge interactions play a more significant role than degree of exfoliation, a result unique in the field of polymer nanocomposites. This demonstrates that even a combination of polymer/nanofiller compatibility and thermodynamically stable nanofiller dispersion levels may not give rise to reinforcement. These findings provide an important caveat when attempting to connect structure and properties in polymer nanocomposites, and useful guidance in the design of optimized polymer/layered silicate nanocomposites in particular. © 2009 American Chemical Society.

  2. Silicon reduces aluminum accumulation in rats: relevance to the aluminum hypothesis of Alzheimer disease.

    Science.gov (United States)

    Bellés, M; Sánchez, D J; Gómez, M; Corbella, J; Domingo, J L

    1998-06-01

    In recent years, a possible relation between the aluminum and silicon levels in drinking water and the risk of Alzheimer disease (AD) has been established. It has been suggested that silicon may have a protective effect in limiting oral aluminum absorption. The present study was undertaken to examine the influence of supplementing silicon in the diet to prevent tissue aluminum retention in rats exposed to oral aluminum. Three groups of adult male rats were given by gavage 450 mg/kg/day of aluminum nitrate nonahydrate 5 days a week for 5 weeks. Concurrently, animals received silicon in the drinking water at 0 (positive control), 59, and 118 mg Si/L. A fourth group (-Al, - Si) was designated as a negative control group. At the end of the period of aluminum and silicon administration, urines were collected for 4 consecutive days, and the urinary aluminum levels were determined. The aluminum concentrations in the brain (various regions), liver, bone, spleen, and kidney were also measured. For all tissues, aluminum levels were significantly lower in the groups exposed to 59 and 118 mg Si/L than in the positive control group; significant reductions in the urinary aluminum levels of the same groups were also found. The current results corroborate that silicon effectively prevents gastrointestinal aluminum absorption, which may be of concern in protecting against the neurotoxic effects of aluminum.

  3. The Aluminum Deep Processing Project of North United Aluminum Landed in Qijiang

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On April 10,North United Aluminum Company respectively signed investment cooperation agreements with Qijiang Industrial Park and Qineng Electricity&Aluminum Co.,Ltd,signifying the landing of North United Aluminum’s aluminum deep processing project in Qijiang.

  4. Petrophysical Analysis of Siliceous-Ooze Sediments, More Basin, Norwegian Sea

    DEFF Research Database (Denmark)

    Awedalkarim, Ahmed; Sørensen, Morten Kanne; Fabricius, Ida Lykke

    2014-01-01

    Pelagic siliceous-ooze sediments occur above the hydrocarbon reservoir of the Ormen Lange gas field in More Basin, Norwegian Sea. A possible hydrocarbon prospect of siliceous ooze was proposed, but siliceous ooze is significantly different in texture from most commonly known reservoir rocks...

  5. On the silicate crystallinities of oxygen-rich evolved stars and their mass-loss rates

    Science.gov (United States)

    Liu, Jiaming; Jiang, B. W.; Li, Aigen; Gao, Jian

    2017-04-01

    For decades ever since the early detection in the 1990s of the emission spectral features of crystalline silicates in oxygen-rich evolved stars, there is a long-standing debate on whether the crystallinity of the silicate dust correlates with the stellar mass-loss rate. To investigate the relation between the silicate crystallinities and the mass-loss rates of evolved stars, we carry out a detailed analysis of 28 nearby oxygen-rich stars. We derive the mass-loss rates of these sources by modelling their spectral energy distributions from the optical to the far-infrared. Unlike previous studies in which the silicate crystallinity was often measured in terms of the crystalline-to-amorphous silicate mass ratio, we characterize the silicate crystallinities of these sources with the flux ratios of the emission features of crystalline silicates to that of amorphous silicates. This does not require the knowledge of the silicate dust temperatures, which are the major source of uncertainties in estimating the crystalline-to-amorphous silicate mass ratio. With a Pearson correlation coefficient of ∼-0.24, we find that the silicate crystallinities and the mass-loss rates of these sources are not correlated. This supports the earlier findings that the dust shells of low mass-loss rate stars can contain a significant fraction of crystalline silicates without showing the characteristic features in their emission spectra.

  6. 聚合硅酸硫酸铁铝混凝剂的制备表征与混凝性能%Preparation and characterization of poly-aluminiumferric silicate sulfate coagulant and its coagulation property

    Institute of Scientific and Technical Information of China (English)

    张开仕; 曾凤春; 谭超; 朱登磊

    2013-01-01

    A new type of inorganic polymer coagulant,poly-aluminum ferric silicate sulfate (PAFSS),was prepared by alkali leaching,acidic leaching,oxidation,and polymerization.Fly ash,crap iron and waste sulfuric acid were utilized as raw materials.The structure,morphology and coagulation property of the sample were characterized by XRD,TEM,microelectrophoresis,ultrafiltration and coagulation experiments.The results showed that the multi-core PAFSS sample,which possessed larger amounts of Al-O-Si and Fe-O Si,was synthesized from the interaction between Fe3+,Al3+,their hydrating polymers,SO24-and poly-silicic acid.The polymer displayed branch-like structure with higher polymerization degree,and larger molecular weight.The coagulation property of samples was excellent when the Si/(Fe+Al) ratio was equal to 0.06-0.10.pH adaptability was much better than that of commercial polymerized ferric sulfate (PFS),polymerized aluminum chloride (PAC) and poly-aluminum ferric sulfate (PAFS).

  7. Immiscible silicate liquids and phosphoran olivine in Netschaëvo IIE silicate: Analogue for planetesimal core-mantle boundaries

    Science.gov (United States)

    Van Roosbroek, Nadia; Hamann, Christopher; McKibbin, Seann; Greshake, Ansgar; Wirth, Richard; Pittarello, Lidia; Hecht, Lutz; Claeys, Philippe; Debaille, Vinciane

    2017-01-01

    We have investigated a piece of the Netschaëvo IIE iron meteorite containing a silicate inclusion by means of electron microprobe analysis (EMPA) and transmission electron microscopy (TEM). Netschaëvo contains chondrule-bearing clasts and impact melt rock clasts were also recently found. The examined inclusion belongs to the latter and is characterized by a porphyritic texture dominated by clusters of coarse-grained olivine and pyroxene, set in a fine-grained groundmass that consists of new crystals of olivine and a hyaline matrix. This matrix material has a quasi-basaltic composition in the inner part of the inclusion, whereas the edge of the inclusion has a lower SiO2 concentration and is enriched in MgO, P2O5, CaO, and FeO. Close to the metal host, the inclusion also contains euhedral Mg-chromite crystals and small (olivine crystallites containing up to 14 wt% P2O5, amorphous material, and interstitial Cl-apatite crystals. The Si-rich silicate glass globules show a second population of Fe-rich silicate glass droplets, indicating they formed by silicate liquid immiscibility. Together with the presence of phosphoran olivine and quenched Cl-apatite, these textures suggest rapid cooling and quenching as a consequence of an impact event. Moreover, the enrichment of phosphorus in the silicate inclusion close to the metal host (phosphoran olivine and Cl-apatite) indicates that phosphorus re-partitioned from the metal into the silicate phase upon cooling. This probably also took place in pallasite meteorites that contain late-crystallizing phases rich in phosphorus. Accordingly, our findings suggest that oxidation of phosphorus might be a general process in core-mantle environments, bearing on our understanding of planetesimal evolution. Thus, the Netschaëvo sample serves as a natural planetesimal core-mantle boundary experiment and based on our temperature estimates, the following sequence of events takes place: (i) precipitation of olivine (1400-1360 °C), (ii) re

  8. Biological and therapeutic effects of ortho-silicic acid and some ortho-silicic acid-releasing compounds: New perspectives for therapy

    Directory of Open Access Journals (Sweden)

    Jurkić Lela Munjas

    2013-01-01

    Full Text Available Abstract Silicon (Si is the most abundant element present in the Earth's crust besides oxygen. However, the exact biological roles of silicon remain unknown. Moreover, the ortho-silicic acid (H4SiO4, as a major form of bioavailable silicon for both humans and animals, has not been given adequate attention so far. Silicon has already been associated with bone mineralization, collagen synthesis, skin, hair and nails health atherosclerosis, Alzheimer disease, immune system enhancement, and with some other disorders or pharmacological effects. Beside the ortho-silicic acid and its stabilized formulations such as choline chloride-stabilized ortho-silicic acid and sodium or potassium silicates (e.g. M2SiO3; M= Na,K, the most important sources that release ortho-silicic acid as a bioavailable form of silicon are: colloidal silicic acid (hydrated silica gel, silica gel (amorphous silicon dioxide, and zeolites. Although all these compounds are characterized by substantial water insolubility, they release small, but significant, equilibrium concentration of ortho-silicic acid (H4SiO4 in contact with water and physiological fluids. Even though certain pharmacological effects of these compounds might be attributed to specific structural characteristics that result in profound adsorption and absorption properties, they all exhibit similar pharmacological profiles readily comparable to ortho-silicic acid effects. The most unusual ortho-silicic acid-releasing agents are certain types of zeolites, a class of aluminosilicates with well described ion(cation-exchange properties. Numerous biological activities of some types of zeolites documented so far might probably be attributable to the ortho-silicic acid-releasing property. In this review, we therefore discuss biological and potential therapeutic effects of ortho-silicic acid and ortho-silicic acid -releasing silicon compounds as its major natural sources.

  9. Mid-IR water and silicate relation in protoplanetary disks

    Science.gov (United States)

    Antonellini, S.; Bremer, J.; Kamp, I.; Riviere-Marichalar, P.; Lahuis, F.; Thi, W.-F.; Woitke, P.; Meijerink, R.; Aresu, G.; Spaans, M.

    2017-01-01

    Context. Mid-IR water lines from protoplanetary disks around T Tauri stars have a detection rate of 50%. Models have identified multiple physical properties of disks such as dust-to-gas mass ratio, dust size power law distribution, disk gas mass, disk inner radius, and disk scale height as potential explanations for the current detection rate. Aims: In this study, we aim to break degeneracies through constraints obtained from observations. We search for a connection between mid-IR water line fluxes and the strength of the 10 μm silicate feature. Methods: We analyze observed water line fluxes from three blends at 15.17, 17.22 and 29.85 μm published earlier and compute the 10 μm silicate feature strength from Spitzer spectra to search for possible trends. We use a series of published ProDiMo thermo-chemical models, to explore disk dust and gas properties, and also the effects of different central stars. In addition, we produced two standard models with different dust opacity functions, and one with a parametric prescription for the dust settling. Results: Our series of models that vary properties of the grain size distribution suggest that mid-IR water emission anticorrelates with the strength of the 10 μm silicate feature. The models also show that the increasing stellar bolometric luminosity simultaneously enhance the strength of this dust feature and the water lines fluxes. No correlation is found between the observed mid-IR water lines and the 10 μm silicate strength. Two-thirds of the targets in our sample show crystalline dust features, and the disks are mainly flaring. Our sample shows the same difference in the peak strength between amorphous and crystalline silicates that was noted in earlier studies, but our models do not support this intrinsic difference in silicate peak strength. Individual properties of our models are not able to reproduce the most extreme observations, suggesting that more complex dust properties (e.g., vertically changing) are

  10. Laboratory Powder Metallurgy Makes Tough Aluminum Sheet

    Science.gov (United States)

    Royster, D. M.; Thomas, J. R.; Singleton, O. R.

    1993-01-01

    Aluminum alloy sheet exhibits high tensile and Kahn tear strengths. Rapid solidification of aluminum alloys in powder form and subsequent consolidation and fabrication processes used to tailor parts made of these alloys to satisfy such specific aerospace design requirements as high strength and toughness.

  11. Sanmenxia strives to create aluminum industrial base

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>Contradiction between rich alumina resource and relatively weak electrolytic aluminum production capacity is the "bottleneck" inhibiting development of aluminum industry in San-menxia. During the period of "11th Five-Year Development", Sanmenxia will relay on its

  12. Wilson's disease; increased aluminum in liver.

    Science.gov (United States)

    Yasui, M; Yoshimasu, F; Yase, Y; Uebayashi, Y

    1979-01-01

    Interaction of trace metal metabolism was studied in a patient with Wilson's dease. Atomic absorption analysis showed markedly increased urinary excretion of copper and aluminum and an increased aluminum content was found in the biopsied liver by neutron activation analysis. These findings suggest a complicated pathogenetic mechanism involving other metals besides copper in the Wilson's disease.

  13. Recrystallization in Commercially Pure Aluminum

    DEFF Research Database (Denmark)

    Bay, Bent; Hansen, Niels

    1984-01-01

    Recrystallization behavior in commercial aluminum with a purity of 99.4 pct was studied by techniques such as high voltage electron microscopy, 100 kV transmission electron microscopy, and light microscopy. Sample parameters were the initial grain size (290 and 24 microns) and the degree of defor......Recrystallization behavior in commercial aluminum with a purity of 99.4 pct was studied by techniques such as high voltage electron microscopy, 100 kV transmission electron microscopy, and light microscopy. Sample parameters were the initial grain size (290 and 24 microns) and the degree...... (FeAl3), which start to become operative when the degree of deformation is raised from 15 to 30 pct. The temperature of nucleation and of recrystallization decreases when the degree of deformation is increased and the initial grain size is decreased. The recrystallized grain size follows the same...... trend and it is observed that the refinement of the recrystallized grain size caused by an increasing degree of deformation and decreasing initial grain size is enhanced by the FeAl3 particles (when the degree of deformation is raised from 15 to 30 pct). Finally, the structural and kinetic observations...

  14. Aluminum honeycomb impact limiter study

    Energy Technology Data Exchange (ETDEWEB)

    Yaksh, M.C.; Thompson, T.C. (Nuclear Assurance Corp., Norcross, GA (United States)); Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (United States))

    1991-07-01

    Design requirements for a cask transporting radioactive materials must include the condition of the 30-foot free fall of the cask onto an unyielding surface. To reduce the deceleration loads to a tolerable level for all the components of the cask, a component (impact limiter) is designed to absorb the kinetic energy. The material, shape, and method of attachment of the impact limiter to the cask body comprises the design of the impact limiter. The impact limiter material of interest is honeycomb aluminum, and the particular design examined was for the NAC Legal Weight Truck cask (NAC-LWT) for spent fuel from light water reactors. The NAC-LWT has a design weight of 52,000 pounds, and it has a nominal length of 200 inches. The report describes the numerical calculations embodied in the FADE program to determine the accelerations and crush strain resulting from an arbitrary height and angle of orientation. Since the program serves as a design tool, static tests are performed to assess the effect of the shell containing the honeycomb aluminum. The static tests and their results are contained in the study. The static tests are used to demonstrate for licensing purposes the level of accelerations imposed on the cask during a 30-foot drop. 3 refs., 41 figs., 15 tabs.

  15. Aluminum corrosion product release kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Matt, E-mail: Matthew.Edwards@cnl.ca; Semmler, Jaleh; Guzonas, Dave; Chen, Hui Qun; Toor, Arshad; Hoendermis, Seanna

    2015-07-15

    Highlights: • Release of Al corrosion product was measured in simulated post-LOCA sump solutions. • Increased boron was found to enhance Al release kinetics at similar pH. • Models of Al release as functions of time, temperature, and pH were developed. - Abstract: The kinetics of aluminum corrosion product release was examined in solutions representative of post-LOCA sump water for both pressurized water and pressurized heavy-water reactors. Coupons of AA 6061 T6 were exposed to solutions in the pH 7–11 range at 40, 60, 90 and 130 °C. Solution samples were analyzed by inductively coupled plasma atomic emission spectroscopy, and coupon samples were analyzed by secondary ion mass spectrometry. The results show a distinct “boron effect” on the release kinetics, expected to be caused by an increase in the solubility of the aluminum corrosion products. New models were developed to describe both sets of data as functions of temperature, time, and pH (where applicable)

  16. Dye removal from aqueous solution by cobalt-nano particles decorated aluminum silicate: kinetic, thermodynamic and mechanism studies.

    Science.gov (United States)

    Arshadi, M; Faraji, A R; Mehravar, M

    2015-02-15

    This article describes the preparation of a nanoadsorbent containing Co-nanoparticles decorated functionalized SiO2-Al2O3 mixed-oxides as a scavenger toward removal of methyl orange. SiO2-Al2O3 mixed-oxides were functionalized with pyridine-2-carbaldehyde and thereafter, in the next step, Co-nanoparticle was prepared over the modified mixed-oxides. The as-prepared nanoadsorbent was characterized by Fourier transform infrared (FTIR), UV-visible diffuse reflectance spectra (UV-vis DRS), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), electron paramagnetic resonance (EPR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results showed that Co-nanoparticle with average size of about 5-25 nm was immobilized successfully on the surface of modified mixed-oxides and was widely dispersed. EPR and CV of Si/Al-PAEA=PyCA@CoNP confirmed that most of the covalently bond active sites of the nano-adsorbent are in the form of Co(II) ions. The supported cobalt is a suitable and efficient adsorbent for the removal of methyl orange from aqueous solution. The heterogeneous Co-NPs were found to be effective adsorbent for the removal of methyl orange ions from solution. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. The CV and EIS of the Co-NPs-MO indicates an easily oxidizable environment, this being in agreement with the FTIR data, where the electron density at Co-NPs is higher due to the presence of a donor-electron ligand (methyl orange), that is, reduction of Co-NPs from +3 to +2 oxidation state is more favored.

  17. High-pressure optical spectroscopy and X-ray diffraction studies on synthetic cobalt aluminum silicate garnet

    DEFF Research Database (Denmark)

    N. Taran, Michail; Nestola, Fabrizio; Ohashi, Haruo

    2007-01-01

    The pressure-induced behavior of spin-allowed dd-bands of VIIICo2+ in the absorption spectra of synthetic Co3Al2Si3O12 garnet was studied from 10-4 to 13 GPa. The plots of the peak energy vs. pressure for the three sharpest well resolved bands at ca. 5160, 17 680, and 18 740 cm-1 display small bu...

  18. Gating of Permanent Molds for ALuminum Casting

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  19. Gelling nature of aluminum soaps in oils.

    Science.gov (United States)

    Wang, Xiaorong; Rackaitis, Mindaugas

    2009-03-15

    Aluminum soaps are notable for their ability to form soap-hydrocarbon gels of high viscosity. For more than half a century, it has been believed that the gelling mechanism is due to a formation of polymeric chains of aluminum molecules with the aluminum atoms linking along the axis and with the fatty acid chain extended sideways. Here we report results from an investigation using high-resolution electron microscopy and rheology measurements that clearly resolve the ambiguity. Our results reveal that the gelling mechanism stems from the formation of spherical nano-sized micelles from aluminum soap molecules, and those colloidal micelle particles then aggregate into networks of highly fractal and jammed structures. The earlier proposed polymer chain-like structure is definitely incorrect. The discovery of aluminum soap particles could expand application of these materials to new technologies.

  20. Aluminum-based metal-air batteries

    Energy Technology Data Exchange (ETDEWEB)

    Friesen, Cody A.; Martinez, Jose Antonio Bautista

    2016-01-12

    Provided in one embodiment is an electrochemical cell, comprising: (i) a plurality of electrodes, comprising a fuel electrode that comprises aluminum and an air electrode that absorbs gaseous oxygen, the electrodes being operable in a discharge mode wherein the aluminum is oxidized at the fuel electrode and oxygen is reduced at the air electrode, and (ii) an ionically conductive medium, comprising an organic solvent; wherein during non-use of the cell, the organic solvent promotes formation of a protective interface between the aluminum of the fuel electrode and the ionically conductive medium, and wherein at an onset of the discharge mode, at least some of the protective interface is removed from the aluminum to thereafter permit oxidation of the aluminum during the discharge mode.

  1. Proposal of recycling system for waste aluminum

    Directory of Open Access Journals (Sweden)

    Š. Valenčík

    2008-04-01

    Full Text Available Introduced work is focused on waste aluminum recycling process with objective to propose complex production system for recovering of aluminum and some aluminum alloys. Solution is supported by extended analysis concerning purpose, basis and system sequences for recyclation. Based on that, sources, possibilities and conditions for recycling are formed. This has been used in proposal of manufacturing system. The principle is the structural proposal of manufacturing system, which does not only differentiate the stage of aluminum melting process, but also related stages as gross separation, sizing, containerisation and batching, palletisation, stacking and some related operations. Production system respects technological specifications, requirements for rationalisation of manufacturing systems, technical and economical feasibility conditions and is considered in lower automation level. However production system solves complex problem of recycling of some types of aluminum, it improves flexibility, production, quality (melting by high enforcements and in protective atmosphere and extention of production (final products production.

  2. Trends in the global aluminum fabrication industry

    Science.gov (United States)

    Das, Subodh; Yin, Weimin

    2007-02-01

    The aluminum fabrication industry has become more vital to the global economy as international aluminum consumption has grown steadily in the past decades. Using innovation, value, and sustainability, the aluminum industry is strengthening its position not only in traditional packaging and construction applications but also in the automotive and aerospace markets to become more competitive and to face challenges from other industries and higher industrial standards. The aluminum fabrication industry has experienced a significant geographical shift caused by rapid growth in emerging markets in countries such as Brazil, Russia, India, and China. Market growth and distribution will vary with different patterns of geography and social development; the aluminum industry must be part of the transformation and keep pace with market developments to benefit.

  3. Aluminum phosphate shows more adjuvanticity than Aluminum hydroxide in recombinant hepatitis –B vaccine formulation

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Background: Although a number of investigation have been carried out to find alternative adjuvants to aluminum salts in vaccine formulations, they are still extensively used due to their good track record of safety, low cost and proper adjuvanticity with a variety of antigens. Adsorption of antigens onto aluminum compounds depends heavily on electrostatic forces between adjuvant and antigen. Commercial recombinant protein hepatitis B vaccines containing aluminum hydroxide as adjuvant is facing low induction of immunity in some sections of the vaccinated population. To follow the current global efforts in finding more potent hepatitis B vaccine formulation, adjuvanticity of aluminum phosphate has been compared to aluminum hydroxide. Materials and methods: The adjuvant properties of aluminum hydroxide and aluminum phosphate in a vaccine formulation containing a locally manufactured hepatitis B (HBs surface antigen was evaluated in Balb/C mice. The formulations were administered intra peritoneally (i.p. and the titers of antibody which was induced after 28 days were determined using ELISA technique. The geometric mean of antibody titer (GMT, seroconversion and seroprotection rates, ED50 and relative potency of different formulations were determined. Results: All the adjuvanicity markers obtained in aluminum phosphate formulation were significantly higher than aluminum hydroxide. The geometric mean of antibody titer of aluminum phosphate was approximately three folds more than aluminum hydroxide. Conclusion: Aluminum phosphate showed more adjuvanticity than aluminum hydroxide in hepatitis B vaccine. Therefore the use of aluminum phosphate as adjuvant in this vaccine may lead to higher immunity with longer duration of effects in vaccinated groups.

  4. Penetration experiments in aluminum 1100 targets using soda-lime glass projectiles

    Science.gov (United States)

    Horz, Friedrich; Cintala, Mark J.; Bernhard, Ronald P.; Cardenas, Frank; Davidson, William E.; Haynes, Gerald; See, Thomas H.; Winkler, Jerry L.

    1995-01-01

    The cratering and penetration behavior of annealed aluminum 1100 targets, with thickness varied from several centimeters to ultra-thin foils less than 1 micrometer thick, were experimentally investigated using 3.2 mm diameter spherical soda-lime glass projectiles at velocities from 1 to 7 km/s. The objective was to establish quantitative, dimensional relationships between initial impact conditions (impact velocity, projectile diameter, and target thickness) and the diameter of the resulting crater or penetration hole. Such dimensional relationships and calibration experiments are needed to extract the diameters and fluxes of hypervelocity particles from space-exposed surfaces and to predict the performance of certain collisional shields. The cratering behavior of aluminum 1100 is fairly well predicted. However, crater depth is modestly deeper for our silicate impactors than the canonical value based on aluminum projectiles and aluminum 6061-T6 targets. The ballistic-limit thickness was also different. These differences attest to the great sensitivity of detailed crater geometry and penetration behavior on the physical properties of both the target and impactor. Each penetration experiment was equipped with a witness plate to monitor the nature of the debris plume emanating from the rear of the target. This plume consists of both projectile fragments and target debris. Both penetration hole and witness-plate spray patterns systematically evolve in response to projectile diameter/target thickness. The relative dimensions of the projectile and target totally dominate the experimental products documented in this report; impact velocity is an important contributor as well to the evolution of penetration holes, but is of subordinate significance for the witness-plate spray patterns.

  5. Characterization of aluminum surfaces: Sorption and etching

    Science.gov (United States)

    Polkinghorne, Jeannette Clera

    Aluminum, due to its low density and low cost, is a key material for future lightweight applications. However, like other structural materials, aluminum is subject to various forms of corrosion damage that annually costs the United States approximately 5% of its GNP [1]. The main goal is to investigate the effects of various solution anions on aluminum surfaces, and specifically probe pit initiation and inhibition. Using surface analysis techniques including X-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron microscopy, results have been correlated with those obtained from electrochemical methods and a radiolabeling technique developed in the Wieckowski laboratory. Analysis of data has indicated that important variables include type of anion, solution pH, and applied electrode potential. While aggressive anions such as chloride are usually studied to elucidate corrosion processes to work ultimately toward inhibition, its corrosive properties can be successfully utilized in the drive for higher energy and smaller-scale storage devices. Fundamental information gained regarding anion interaction with the aluminum surface can be applied to tailor etch processes. Standard electrochemical techniques and SEM are respectively used to etch and analyze the aluminum substrate. Aluminum electrolytic capacitors are comprised of aluminum anode foil covered by an anodically grown aluminum oxide dielectric film, electrolytic paper impregnated with electrolyte, and aluminum cathode foil. Two main processes are involved in the fabrication of aluminum electrolytic capacitors, namely etching and anodic oxide formation. Etching of the anode foil results in a higher surface area (up to 20 times area enlargement compared to unetched foil) that translates into a higher capacitance gain, permitting more compact and lighter capacitor manufacture. Anodic oxide formation on the anode, creates the required dielectric to withstand high voltage operation. A

  6. Removal of Cadmium Ions from Aqueous Solution by Silicate-incorporated Hydroxyapatite

    Institute of Scientific and Technical Information of China (English)

    SHI Hebin; ZHONG Hong; LIU Yu; DENG Jinyang

    2007-01-01

    This article reports a preliminary research on silicate-incorporated hydroxyapatite as a new environmental mineral used to remove cadmium ions from aqueous solutions. The silicate-incorporated hydroxyapatite was prepared by coprecipitation and calcining, and silicate was incorporated into the crystal lattice of hydroxyapatite by partial substitution of phosphate. The amount of cadmium ions removed by silicate-incorporated hydroxyapatite was significantly elevated, which was 76% higher than that of pure hydroxyapatite. But the sorption behavior of cadmium ions on silicate-incorporated hydroxyapatite was similar to that of pure hydroxyapatite. Morphological study revealed that silicate incorporation confined the crystal growth and increased the specific surface area of hydroxyapatite,which were in favor of enhancing the cadmium ion sorpfion capacity of the samples. Incorporation of silicate into hydroxyapatite seems to be an effective approach to improve the environmental property of hydroxyapatite on removal of aqueous cadmium ions.

  7. IN SITU INFRARED MEASUREMENTS OF FREE-FLYING SILICATE DURING CONDENSATION IN THE LABORATORY

    Energy Technology Data Exchange (ETDEWEB)

    Ishizuka, Shinnosuke; Kimura, Yuki [Institute of Low Temperature Science, Hokkaido University, Hokkaido Sapporo 060-0819 (Japan); Sakon, Itsuki [Department of Astronomy, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2015-04-20

    We developed a new experimental system for infrared (IR) measurements on free-flying nucleating nanoparticles in situ and applied it to studies on silicate particles. We monitored the condensation of magnesium-bearing silicate nanoparticles from thermally evaporated magnesium and silicon monoxide vapor under an atmosphere of oxygen and argon. The IR spectrum of newly condensed particles showed a spectral feature for non-crystalline magnesium-bearing silicate that is remarkably consistent with the IR spectrum of astronomically observed non-crystalline silicate around oxygen-rich evolved stars. The silicate crystallized at <500 K and eventually developed a high crystallinity. Because of the size effects of nanoparticles, the silicate would be expected to be like a liquid at least during the initial stages of nucleation and growth. Our experimental results therefore suggest decreasing the possible formation temperature of crystalline silicates in dust formation environments with relatively higher pressure.

  8. Modeling the viscosity of silicate melts containing manganese oxide

    Directory of Open Access Journals (Sweden)

    Kim Wan-Yi

    2013-01-01

    Full Text Available Our recently developed model for the viscosity of silicate melts is applied to describe and predict the viscosities of oxide melts containing manganese oxide. The model requires three pairs of adjustable parameters that describe the viscosities in three systems: pure MnO, MnO-SiO2 and MnO-Al2O3-SiO2. The viscosity of other ternary and multicomponent silicate melts containing MnO is then predicted by the model without any additional adjustable model parameters. Experimental viscosity data are reviewed for melts formed by MnO with SiO2, Al2O3, CaO, MgO, PbO, Na2O and K2O. The deviation of the available experimental data from the viscosities predicted by the model is shown to be within experimental error limits.

  9. Inorganic phosphors in lead-silicate glass for white LEDs

    Science.gov (United States)

    Nikonorov, N. V.; Kolobkova, E. V.; Aseev, V. A.; Bibik, A. Yu.; Nekrasova, Ya. A.; Tuzova, Yu. V.; Novogran, A. I.

    2016-09-01

    Luminescent composites of the "phosphor-in-glass" type, based on a highly reflective lead-silicate matrix and fine-grained powders of YAG:Ce3+ and SiAlON:Eu2+ crystals, are developed and synthesized. Phosphor and glass powders are sintered at a temperature of 550°C to obtain phosphor samples for white LEDs. The composites are analyzed by X-ray diffraction and luminescence spectroscopy. The dependence of the light quantum yield on the SiAlON:Eu2+ content in the samples is investigated. A breadboard of a white LED is designed using a phosphor-in-glass composite based on lead-silicate glass with a low glasstransition temperature. The total emission spectra of a blue LED and glass-based composites are measured. The possibility of generating warm white light by choosing an appropriate composition is demonstrated.

  10. Effective elastic moduli of polymer-layered silicate nanocomposites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Polymer-layered silicate (PLS) nanocomposites exhibit some mechanical properties that are much better than conventional polymer filled composites. A relatively low content of layered silicate yields a significant enhancement of material performance. After the volume fraction of clay reaches a relatively low "critical value"; however, further increasing does not show a greater stiffening effect. This phenomenon is contrary to previous micromechanical pre-dictions and is not understood well. Based on the analysis on the microstructures of PLS nanocomposites, the present note provides an insight into the physical micromechanisms of the above unexpected phenomenon. The Mori-Tanaka scheme and a numerical method are employed to estimate the effec-tive elastic moduli of such a composite.

  11. The viscosity window of the silicate glass foam production

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    2017-01-01

    The production of silicate glass foam allows diverse resources and waste materials to be used in the production. Testing of such large palette of materials complicates and prolongs the optimisation process. Therefore, it is crucial to find a universal criterion for foaming silicate glass melts...... which can offer a practical starting point for the optimisation procedure. The melt viscosity might be the most important parameter for controlling the foaming process and the glass foam density. In this work, we attempt to define a viscosity range in which foaming of different glasses results...... in a maximum of foam expansion. The expansion maximum is obtained for different glasses (labware, E-glass, CRT panel, soda-lime-silica) by foaming with CaCO3 at isokom temperature and from literature data. In general, the viscosity window was found to be within 104–106 Pa s when foaming with MnO2 or metal...

  12. Dry reusing and wet reclaiming of used sodium silicate sand

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the characteristics of used sodium silicate sand and the different use requirements for recycled sand, "dry reusing and wet reclaiming of used sodium silicate sand" is considered as the most suitable technique for the used sand. When the recycled sand is used as support sand, the used sand is only reused by dry process including breaking, screening, dust-removal, etc., and it is not necessary that the used sand is reclaimed with strongly rubbing and scraping method, but when the recycled sand is used as facing sand (or single sand), the used sand must be reclaimed by wet method for higher removal rate of the residual binders. The characteristics and the properties of the dry reused sand are compared with the wet reclaimed sand after combining the different use requirements of support sand and facing sand (or single sand), and above the most adaptive scheme has also been validated.

  13. Xe and Kr analyses of silicate inclusions from iron meteorites.

    Science.gov (United States)

    Bogard, D. D.; Huneke, J. C.; Burnett, D. S.; Wasserburg, G. J.

    1971-01-01

    Measurements have been conducted of the amounts and isotopic composition of Xe and Kr in silicate inclusions of several iron meteorites. It is shown that the Xe and Kr contents are comparable to chondritic values. The isotopic compositions show trapped gas of both chondritic and atmospheric composition. Large spallation effects occur in some of the meteorites; the spallation spectra in some instances differ from those reported for stone meteorites. In several meteorites, very large neutron capture effects on Br and I occur. All samples have pronounced Xe129 excesses which apparently indicate differences in the formation times from chondrites of less than about 100 million years; however, the presence of trapped Xe132 in silicates which were enclosed in molten Fe-Ni and cooled slowly proves that they were not entirely outgassed, so that some of the Xe129 excess may also be trapped.

  14. Thermochemistry of Rare Earth Silicates for Environmental Barrier Coatings

    Science.gov (United States)

    Costa, Gustavo; Jacobson, Nathan

    2015-01-01

    Rare earth silicates are promising candidates as environmental protective coatings (EBCs) for silica-forming ceramics and composites in combustion environments since they are predicted to have lower reactivity with the water vapor combustion products. The reactivity of rare earth silicates is assessed by the thermodynamic activity of the silica component which is best measured by Knudsen effusion mass spectrometry (KEMS). Here, we discuss a novel method based on a reducing agent to increase the partial pressure of SiO(g) which is then used to calculate thermodynamic activity of silica in Y2O3-SiO2 and Yb2O3-SiO2 systems. After the KEMS measurements, samples were probed by X-ray diffraction and their phase content was calculated from Rietveld refinement.

  15. Calc-silicate mineralization in active geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Bird, D.K.; Schiffman, P.; Elders, W.A.; Williams, A.E.; McDowell, S.D.

    1983-01-01

    The detailed study of calc-silicate mineral zones and coexisting phase relations in the Cerro Prieto geothermal system were used as examples for thermodynamic evaluation of phase relations among minerals of variable composition and to calculate the chemical characteristics of hydrothermal solutions compatible with the observed calc-silicate assemblages. In general there is a close correlation between calculated and observed fluid compositions. Calculated fugacities of O{sub 2} at about 320{degrees}C in the Cerro Prieto geothermal system are about five orders of magnitude less than that at the nearby Salton Sea geothermal system. This observation is consistent with the occurrence of Fe{sup 3+} rich epidotes in the latter system and the presence of prehnite at Cerro Prieto.

  16. Chemical Fractionation in the Silicate Vapor Atmosphere of the Earth

    CERN Document Server

    Pahlevan, Kaveh; Eiler, John; 10.1016/j.epsl.2010.10.03

    2010-01-01

    Despite its importance to questions of lunar origin, the chemical composition of the Moon is not precisely known. In recent years, however, the isotopic composition of lunar samples has been determined to high precision and found to be indistinguishable from the terrestrial mantle despite widespread isotopic heterogeneity in the Solar System. In the context of the giant-impact hypothesis, this level of isotopic homogeneity can evolve if the proto-lunar disk and post-impact Earth undergo turbulent mixing into a single uniform reservoir while the system is extensively molten and partially vaporized. In the absence of liquid-vapor separation, such a model leads to the lunar inheritance of the chemical composition of the terrestrial magma ocean. Hence, the turbulent mixing model raises the question of how chemical differences arose between the silicate Earth and Moon. Here we explore the consequences of liquid-vapor separation in one of the settings relevant to the lunar composition: the silicate vapor atmosphere...

  17. Nanoindentation investigation of creep properties of calcium silicate hydrates

    OpenAIRE

    Vandamme, Matthieu; ULM, Franz Josef

    2013-01-01

    The creep properties of calcium silicate hydrates (C-S-H) are assessed by means of nanoindentation creep experiments on a wide range of substoichiometric cement pastes. We observe that, after a few seconds, the measured creep compliance of C-S-H is very well captured by a logarithmic time function. The rate of the logarithmic creep is found to scale in a unique manner with indentation modulus, indentation hardness, and packing density, independent of processing, mix proportions, indenter geom...

  18. Dentin-cement Interfacial Interaction: Calcium Silicates and Polyalkenoates

    OpenAIRE

    Atmeh, A.R.; Chong, E.Z.; Richard, G; Festy, F.; Watson, T.F.

    2012-01-01

    The interfacial properties of a new calcium-silicate-based coronal restorative material (Biodentine™) and a glass-ionomer cement (GIC) with dentin have been studied by confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), micro-Raman spectroscopy, and two-photon auto-fluorescence and second-harmonic-generation (SHG) imaging. Results indicate the formation of tag-like structures alongside an interfacial layer called the “mineral infiltration zone”, where the alkaline c...

  19. Diapiric ascent of silicic magma beneath the Bolivian Altiplano

    OpenAIRE

    Del Potro, R.; M. Díez; Blundy, J.; Camacho, Antonio G.; Gottsmann, Joachim

    2013-01-01

    The vertical transport of large volumes of silicic magma, which drives volcanic eruptions and the long-term compositional evolution of the continental crust, is a highly debated problem. In recent years, dyking has been favored as the main ascent mechanism, but the structural connection between a distributed configuration of melt-filled pores in the source region and shallow magma reservoirs remains unsolved. In the Central Andes, inversion of a new high-resolution Bouguer anomaly data over t...

  20. Scenario of Growing Crops on Silicates in Lunar Gargens

    Science.gov (United States)

    Kozyrovska, N.; Kovalchuk, M.; Negutska, V.; Lar, O.; Korniichuk, O.; Alpatov, A.; Rogutskiy, I.; Kordyum, V.; Foing, B.

    Self-perpetuating gardens will be a practical necessity for humans, living in permanently manned lunar bases. A lunar garden has to supplement less appetizing packaged food brought from the Earth, and the ornamental plants have to serve as valuable means for emotional relaxation of crews in a hostile lunar environment. The plants are less prone to the inevitable pests and diseases when they are in optimum condition, however, in lunar greenhouses there is a threat for plants to be hosts for pests and predators. Although the lunar rocks are microorganism free, there will be a problem with the acquired infection (pathogens brought from the Earth) in the substrate used for the plant growing. On the Moon pests can be removed by total fumigation, including seed fumigation. However, such a treatment is not required when probiotics (biocontrol bacteria) for seed inoculation are used. A consortium of bacteria, controlling plant diseases, provides the production of an acceptable harvest under growth limiting factors and a threatening infection. To model lunar conditions we have used terrestrial alumino-silicate mineral anorthosite (Malyn, Ukraine) which served us as a lunar mineral analog for a substrate composition. With the idea to provide a plant with some essential growth elements siliceous bacterium Paenibacillus sp. has been isolated from alumino-silicate mineral, and a mineral leaching has been simulated in laboratory condition. The combination of mineral anorthosite and siliceous bacteria, on one hand, and a consortium of beneficial bacteria for biocontrol of plant diseases, on the other hand, are currently used in model experiments to examine the wheat and potato growth and production in cultivating chambers under controlled conditions.

  1. Sulfur Solubility In Silicate Melts: A Thermochemical Model

    Science.gov (United States)

    Moretti, R.; Ottonello, G.

    A termochemical model for calculating sulfur solubility of simple and complex silicate melts has been developed in the framework of the Toop-Samis polymeric approach combined with a Flood - Grjotheim theoretical treatment of silicate slags [1,2]. The model allows one to compute sulfide and sulfate content of silicate melts whenever fugacity of gaseous sulphur is provided. "Electrically equivalent ion fractions" are needed to weigh the contribution of the various disproportion reactions of the type: MOmelt + 1/2S2 ,gas MSmelt+1/2O2 ,gas (1) MOmelt + 1/2S2 ,gas + 3/2O2 ,gas MSO4 ,melt (2) Eqs. 1 and 2 account for the oxide-sulfide and the oxide-sulfate disproportiona- tion in silicate melt. Electrically equivalent ion fractions are computed, in a fused salt Temkin notation, over the appropriate matrixes (anionic and cationic). The extension of such matrixes is calculated in the framework of a polymeric model previously developed [1,2,3] and based on a parameterization of acid-base properties of melts. No adjustable parameters are used and model activities follow the raoultian behavior implicit in the ion matrix solution of the Temkin notation. The model is based on a huge amount of data available in literature and displays a high heuristic capability with virtually no compositional limits, as long as the structural role assigned to each oxide holds. REFERENCES: [1] Ottonello G., Moretti R., Marini L. and Vetuschi Zuccolini M. (2001), Chem. Geol., 174, 157-179. [2] Moretti R. (2002) PhD Thesis, University of Pisa. [3] Ottonello G. (2001) J. Non-Cryst. Solids, 282, 72-85.

  2. In vitro studies of calcium phosphate silicate bone cements.

    Science.gov (United States)

    Zhou, Shuxin; Ma, Jingzhi; Shen, Ya; Haapasalo, Markus; Ruse, N Dorin; Yang, Quanzu; Troczynski, Tom

    2013-02-01

    A novel calcium phosphate silicate bone cement (CPSC) was synthesized in a process, in which nanocomposite forms in situ between calcium silicate hydrate (C-S-H) gel and hydroxyapatite (HAP). The cement powder consists of tricalcium silicate (C(3)S) and calcium phosphate monobasic (CPM). During cement setting, C(3)S hydrates to produce C-S-H and calcium hydroxide (CH); CPM reacts with the CH to precipitate HAP in situ within C-S-H. This process, largely removing CH from the set cement, enhances its biocompatibility and bioactivity. The testing results of cell culture confirmed that the biocompatibility of CPSC was improved as compared to pure C(3)S. The results of XRD and SEM characterizations showed that CPSC paste induced formation of HAP layer after immersion in simulated body fluid for 7 days, suggesting that CPSC was bioactive in vitro. CPSC cement, which has good biocompatibility and low/no cytotoxicity, could be a promising candidate as biomedical cement.

  3. Structure and dynamics of iron doped and undoped silicate glasses

    Science.gov (United States)

    Santos, Cristiane N.; Meneses, Domingos D. S.; Echegut, Patrick; Lecomte, Emmanuel

    2010-03-01

    The optical properties of common silicate glass compositions are well known at room temperature. However, their radiative properties and structural evolution of these glasses with temperature are still largely unexplored. In this work we have measured the emissivity of a set of iron doped and undoped silicate and borosilicate glasses over an unprecedented temperature (up to 1700 K) and spectral range (40 -- 20000 cm-1). This was achieved by means of a home-made apparatus composed of a CO2 laser as the heat source, a black-body reference and two spectrometers. The optical functions were assessed using a dielectric function model [1], and the structure and dynamics of the glassy network, as well the absorption of iron species in different redox states were evidenced. We believe that these new data will help to understand the heat transfer in molten silicates. [4pt] [1] D. D. S. Meneses, G. Gruener, M. Malki, and P. Echegut, J. Non-Cryst. Solids 351, 124 (2005)

  4. The Partitioning of Tungsten bwtween Aqueous Fluids and Silicate Melts

    Institute of Scientific and Technical Information of China (English)

    许永胜; 张本仁; 等

    1993-01-01

    An experimental study has been carried out to determine the partition coefficients of tungsten between aqueous fluids and granitic melts at 800℃ and 1.5kb with natural granite as the starting material,The effects of the solution on the partition coefficients of tungsten show a wequence of P>co32->B>H2O.The effects are limited(generally KD<0.3)and the tungsten shows a preferential trend toward the melt over the aqueous fiuid.The value of KD increases with increasing concentration of phosphorus;the KD increases first and then reduces with the concentration of CO32-;when temperature decreases,the KD between the solution of CO32- and the silicate melt increases,and that between the solution of B4O72- and the silicate melt decreases.The partition coefficients of phosphorus and sodium between fluids and silicate melts have been calculated from the concentrations of the elements in the melts.The KD value for phosphorus is 0.38 and that for sodium is 0.56.Evidence shows that the elements tend to become richer and richer in the melts.

  5. Electrical properties of iron doped apatite-type lanthanum silicates

    Institute of Scientific and Technical Information of China (English)

    SHI Qingle; ZHANG Hua

    2012-01-01

    The effect of Fe doping on the electrical properties of lanthanum silicates was investigated.The apatite-type lanthanum silicates La10Si6-xFexO27-x/2 (x=0.2,0.4,0.6,0.8,1.0) were synthesized via sol-gel process.The unit cell volume increased with Fe doping because the ionic radius of Fe3+ ion is larger than that of Si4+ ion.The conductivities of La10Si6-xFexO27 x/2 first increased and then decreased with the increasing of Fe content.The increase of the conductivity might be attributed to the distortion of the cell lattice,which assisted the migration of the interstitial oxygen ions.The decrease of the conductivity might be caused by the lower concentration of interstitial oxygen ions.The optimum Fe doping content in lanthanum silicates was 0.6.La10Si5.4Fe0.6O26.7 exhibited the highest ionic conductivity of 2.712× 10-2 S/cm at 800 ℃.The dependence of conductivity on oxygen partial pressure p(O2) suggested that the conductivity of La10Si6-xFexO27-x/2 was mainly contributed by ionic conductivity.

  6. DEVELOPMENT AND DEPLOYMENT OF SHOTCRETE REFRACTORIES FOR ALUMINUM ROTARY FURNACE APPLICATION

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla

    2013-01-01

    Work was performed by Oak Ridge National Laboratory (ORNL) in the United States, in collaboration with the industrial refractory manufacturer Minteq International, Inc. (MINTEQ), academic research partner Missouri University of Science and Technology (MS&T) and end users to employ novel refractory systems and techniques to reduce energy consumption of refractory lined vessels found in the aluminum industry. The project aim was to address factors that limit the applicability of currently available refractory materials such as chemical attack, mechanical degradation, use temperature, and installation or repair issues. To this end, as part of the overall project, shotcretable refractory compositions were developed based on alumino-silicate based structures utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques for use in rotary dross furnaces. Additionally a shotcretable high strength insulating back-up lining material was also developed for use in this and other applications. Development efforts, materials validation, and results from industrial validation trials are discussed.

  7. Method 366.0 Determination of Dissolved Silicate in Estuarine and Coastal Watersby Gas Segmented Continuous Flow Colorimetric Analysis

    Science.gov (United States)

    This method provides a procedure for the determination of dissolved silicate concentration in estuarine and coastal waters. The dissolved silicate is mainly in the form of silicic acid, H SiO , in estuarine and 4 4 coastal waters. All soluble silicate, including colloidal silici...

  8. Development of Alcoa aluminum foam products

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, J.D.; Crowley, M.D.; Wang, W.; Wilhelmy, D.M.; Hunter, D.E. [Alcoa Technical Center, Alcoa Center, PA (United States)

    2007-07-01

    A new lightweight aluminum foam product was described. The foam was made through the controlled decomposition of carbonate powders within molten aluminum and was able to resist both coalescence and drainage. The fine-celled aluminum foam derived its physical and mechanical properties from the properties of the aluminum alloy matrix from which they were produced. The rheology of the molten aluminum was modified to provide a superior mesostructure. Stabilization was achieved by creating a solid-gas-liquid suspension initiated by the addition of carbonates into an aluminum alloy melt. A cascade of chemical reactions then occurred within the melt to create a foamable suspension. Carbon monoxide (CO) was generated to initiate an additional sequence of chemical reactions which resulted in the formation of solid particles within the liquid metal. CO reacted with liquid Al to form graphite. The graphite then reacted with Al to form aluminum carbide (Al{sub 4}C{sub 3}). The microstructural, mesostructural, and mechanical character of the foams produced under different processing conditions were examined. Details of experimental test procedures were also described. It was concluded that the specific crush energy absorption was as high as 20 kJ/kg. The foam exhibited a bending stiffness that was approximately 20 to 30 times higher than balsa and polymer foams. 14 refs., 2 tabs., 7 figs.

  9. Lead exposure from aluminum cookware in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Weidenhamer, Jeffrey D.; Kobunski, Peter A. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Kuepouo, Gilbert [Research and Education Centre for Development (CREPD), Yaounde (Cameroon); Corbin, Rebecca W. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Gottesfeld, Perry, E-mail: pgottesfeld@okinternational.org [Occupational Knowledge International, San Francisco, CA (United States)

    2014-10-15

    Blood lead levels have decreased following the removal of lead from gasoline in most of the world. However, numerous recent studies provide evidence that elevated blood lead levels persist in many low and middle-income countries around the world at much higher prevalence than in the more developed countries. One potential source of lead exposure that has not been widely investigated is the leaching of lead from artisanal aluminum cookware, which is commonly used in the developing world. Twenty-nine samples of aluminum cookware and utensils manufactured by local artisans in Cameroon were collected and analyzed for their potential to release lead during cooking. Source materials for this cookware included scrap metal such as engine parts, radiators, cans, and construction materials. The lead content of this cookware is relatively low (< 1000 ppm by X-ray fluorescence), however significant amounts of lead, as well as aluminum and cadmium were released from many of the samples using dilute acetic acid extractions at boiling and ambient temperatures. Potential exposures to lead per serving were estimated to be as high as 260 μg, indicating that such cookware can pose a serious health hazard. We conclude that lead, aluminum and cadmium can migrate from this aluminum cookware during cooking and enter food at levels exceeding recommended public health guidelines. Our results support the need to regulate lead content of materials used to manufacture these pots. Artisanal aluminum cookware may be a major contributor to lead poisoning throughout the developing world. Testing of aluminum cookware in other developing countries is warranted. - Highlights: • Cookware is manufactured in Cameroon from scrap aluminum including car parts. • Twenty-nine cookware samples were evaluated for their potential to leach lead. • Boiling extractions to simulate the effects of cooking released significant lead. • Potential lead exposures per serving are estimated as high as 260 μg.

  10. Replacement of glass in the Nakhla meteorite by berthierine: Implications for understanding the origins of aluminum-rich phyllosilicates on Mars

    Science.gov (United States)

    Lee, Martin R.; Chatzitheodoridis, Elias

    2016-09-01

    A scanning and transmission electron microscope study of aluminosilicate glasses within melt inclusions from the Martian meteorite Nakhla shows that they have been replaced by berthierine, an aluminum-iron serpentine mineral. This alteration reaction was mediated by liquid water that gained access to the glasses along fractures within enclosing augite and olivine grains. Water/rock ratios were low, and the aqueous solutions were circumneutral and reducing. They introduced magnesium and iron that were sourced from the dissolution of olivine, and exported alkalis. Berthierine was identified using X-ray microanalysis and electron diffraction. It is restricted in its occurrence to parts of the melt inclusions that were formerly glass, thus showing that under the ambient physico-chemical conditions, the mobility of aluminum and silicon were low. This discovery of serpentine adds to the suite of postmagmatic hydrous silicates in Nakhla that include saponite and opal-A. Such a variety of secondary silicates indicates that during aqueous alteration compositionally distinct microenvironments developed on sub-millimeter length scales. The scarcity of berthierine in Nakhla is consistent with results from orbital remote sensing of the Martian crust showing very low abundances of aluminum-rich phyllosilicates.

  11. Investigation of synthesized Be-bearing silicate glass as laboratory reference sample at X-ray electron probe microanalysis of silicates

    Science.gov (United States)

    Belozerova, Olga Yu.; Mikhailov, Mikhail A.; Demina, Tamara V.

    2017-01-01

    The article discusses estimates of the stability and homogeneity in Be-Mg-Al-silicate glass produced by the authors and its applicability as a laboratory reference sample for X-ray electron probe microanalysis (EPMA) of Be-bearing silicate matters: crystals and quenching melt (glasses), silicates and oxides. The results were obtained using Superprobe-733 and Superprobe JXA-8200 (JEOL Ltd, Japan) devices. The sample homogeneity was studied on macro (10-100 μm) and micro (1-10 μm) levels and was evaluated by the scheme of dispersion analysis. The applicability of Be-bearing silicate glass as a reference sample for Mg, Al, Si determinations was tested on the international certified reference glasses and laboratory reference samples of minerals with a known composition. The obtained experimental metrological characteristics correspond to the "applied geochemistry" type of analysis (second category) and suggest that Be-bearing silicate glass is appropriate as a laboratory reference sample for EPMA of Be-bearing silicate matters, silicates and oxides. Using Be-Mg-Al-silicate glass as a reference sample we obtained satisfactory data on the composition of both some minerals including cordierite and beryllium cordierite, beryllium indialite, beryl and metastable phases (chrysoberyl, compounds with structure of β-quartz and petalite).

  12. Mg-perovskite/silicate melt and magnesiowuestite/silicate melt partition coefficients for KLB-1 at 250 Kbars

    Science.gov (United States)

    Drake, Michael J.; Rubie, David C.; Mcfarlane, Elisabeth A.

    1992-01-01

    The partitioning of elements amongst lower mantle phases and silicate melts is of interest in unraveling the early thermal history of the Earth. Because of the technical difficulty in carrying out such measurements, only one direct set of measurements was reported previously, and these results as well as interpretations based on them have generated controversy. Here we report what are to our knowledge only the second set of directly measured trace element partition coefficients for a natural system (KLB-1).

  13. Fatigue analysis of aluminum drill pipes

    Directory of Open Access Journals (Sweden)

    João Carlos Ribeiro Plácido

    2005-12-01

    Full Text Available An experimental program was performed to investigate the fundamental fatigue mechanisms of aluminum drill pipes. Initially, the fatigue properties were determined through small-scale tests performed in an optic-mechanical fatigue apparatus. Additionally, full-scale fatigue tests were carried out with three aluminum drill pipe specimens under combined loading of cyclic bending and constant axial tension. Finally, a finite element model was developed to simulate the stress field along the aluminum drill pipe during the fatigue tests and to estimate the stress concentration factors inside the tool joints. By this way, it was possible to estimate the stress values in regions not monitored during the fatigue tests.

  14. Nanshan Aluminum Reached Strategic Cooperation with CSR Corporation Limited

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    As a key supplier of aluminum profiles and aluminum plate,sheet and trip products for CSR Corporation Limited,Nanshan Aluminum will join hands with CSR Corporation Limited to reach strategic cooperation.On January 5,Nanshan Aluminum signed strategic cooperation agreement with CSR Sifang Locomotive&Rolling; Stock Co.,Ltd,both

  15. Changes in porosity of foamed aluminum during solidification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to control the porosity of foamed aluminum, the changes in the porosity of foamed aluminum melt in the processes of foaming and solidification, the distribution of the porosity of foamed aluminum, and the relationship between them were studied. The results indicated that the porosity of foamed aluminum coincides well with the foaming time.

  16. Confined Water in Layered Silicates: The Origin of Anomalous Thermal Expansion Behavior in Calcium-Silicate-Hydrates.

    Science.gov (United States)

    Krishnan, N M Anoop; Wang, Bu; Falzone, Gabriel; Le Pape, Yann; Neithalath, Narayanan; Pilon, Laurent; Bauchy, Mathieu; Sant, Gaurav

    2016-12-28

    Water, under conditions of nanoscale confinement, exhibits anomalous dynamics, and enhanced thermal deformations, which may be further enhanced when such water is in contact with hydrophilic surfaces. Such heightened thermal deformations of water could control the volume stability of hydrated materials containing nanoconfined structural water. Understanding and predicting the thermal deformation coefficient (TDC, often referred to as the CTE, coefficient of thermal expansion), which represents volume changes induced in materials under conditions of changing temperature, is of critical importance for hydrated solids including: hydrogels, biological tissues, and calcium silicate hydrates, as changes in their volume can result in stress development, and cracking. By pioneering atomistic simulations, we examine the physical origin of thermal expansion in calcium-silicate-hydrates (C-S-H), the binding agent in concrete that is formed by the reaction of cement with water. We report that the TDC of C-S-H shows a sudden increase when the CaO/SiO2 (molar ratio; abbreviated as Ca/Si) exceeds 1.5. This anomalous behavior arises from a notable increase in the confinement of water contained in the C-S-H's nanostructure. We identify that confinement is dictated by the topology of the C-S-H's atomic network. Taken together, the results suggest that thermal deformations of hydrated silicates can be altered by inducing compositional changes, which in turn alter the atomic topology and the resultant volume stability of the solids.

  17. Efficient Desilication by Adsorption with Aluminum Salt-modified Bentonite from Green Liquor

    Directory of Open Access Journals (Sweden)

    Tao Lin

    2014-06-01

    Full Text Available The objective of this work was to investigate the possibility of using Na-bentonite as a raw material to produce aluminum salt-modified bentonite (AlMB for desilication of green liquor. Batch experiments were carried out by varying the experimental parameters to find the optimum conditions. The optimum adsorbent dose was 20 g/L. The maximum adsorptions of 96.37% and 87.22% took place at pH 7.4 when the initial concentrations of silicate in green liquor were 4 and 6 g/L, respectively. The kinetic models showed that the process included physical adsorption and chemical adsorption. Finally, this study showed that the extent of desorption was 56.78% for silicate after desorption of AlMB in 2 M NaOH solution. The AlMB is an efficient and novel adsorbent for desilicating that can provide a good reference for the “silicon influence” in a papermaking mill.

  18. Coordination Structure of Aluminum in Magnesium Aluminum Hydroxide Studied by 27Al NMR

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The coordination structure of aluminum in magnesium aluminum hydroxide was studiedby 27Al NMR. The result showed that tetrahedral aluminum (AlⅣ) existed in magnesiumaluminum hydroxide, and the contents of AlⅣ increased with the increase of the ratio of Al/Mg andwith the peptizing temperature. AlⅣ originated from the so-called Al13 polymer with the structureof one Al tetrahedron surrounded by twelve Al octahedrons.

  19. South West Aluminum: Next year The Capacity of Auto-use Aluminum Sheet will Reach 5000 Tonnes

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Following supplying supporting aluminum products for"Shenzhou"spacecraft,"Long March"rocket,Boeing and Airbus,South West Aluminum again tapped new economic growth points,i.e.automobile-use aluminum products.According to what the reporter has learned from South West Aluminum Group recently,this group has finished early stage

  20. Drug: D03236 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D03236 Drug Synthetic aluminum silicate (JP16); Aluminum silicate, synthetic (JAN);...ning agents D03236 Synthetic aluminum silicate (JP16); Aluminum silicate, synthetic (JAN) CAS: 12141-46-7 PubChem: 17397389 ...

  1. Drug: D03237 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D03237 Drug Natural aluminum silicate (JP16); Aluminum silicate, natural (JAN); Ads...agents D03237 Natural aluminum silicate (JP16); Aluminum silicate, natural (JAN) CAS: 12141-46-7 PubChem: 17397390 ...

  2. Aluminum recovery as a product with high added value using aluminum hazardous waste.

    Science.gov (United States)

    David, E; Kopac, J

    2013-10-15

    The samples of hazardous aluminum solid waste such as dross were physically and chemically characterized. A relationship between density, porosity and metal content of dross was established. The paper also examines the chemical reactions involving aluminum dross in landfill and the negative consequences. To avoid environmental problems and to recovery the aluminum, a processing method was developed and aluminum was recovered as an added value product such as alumina. This method refers to a process at low temperature, in more stages: acid leaching, purification, precipitation and calcination. At the end of this process aluminum was extracted, first as Al(3+) soluble ions and final as alumina product. The composition of the aluminum dross and alumina powder obtained were measured by applying the leaching tests, using atomic absorption spectrometry (AAS) and chemical analysis. The mineralogical composition of aluminum dross samples and alumina product were determined by X-ray diffraction (XRD) and the morphological characterization was performed by scanning electron microscopy (SEM). The method presented in this work allows the use of hazardous aluminum solid waste as raw material to recover an important fraction from soluble aluminum content as an added value product, alumina, with high grade purity (99.28%).

  3. Preliminary Study on Aluminum Content of Foods and Aluminum Intake of Residents in Tianjin

    Institute of Scientific and Technical Information of China (English)

    XUGe-Sheng; JINRng-Pei; 等

    1993-01-01

    Aluminum contents of 64 kinds of foods in Tianjin were detrmined.The results showed that the aluminum levels in diffeent kinds of foods varied greatly,and most foodstuffs from natural sources(including contamination from food processing)contained less than 10mg/kg,Aluminum contents were higher in foodstuffs of plant origin,especiallydry beans containing large amounts of aluminum naturally.Lower concentration of aluminum seemed to be present in foodstuffs of animal origin.It was estimated that the potential daily intake of aluminum per person from natural dietary sources in Tianjin was about 3.79 mg.This estimated figure of dietary aluminum intake was very close to the measured data from 24 daily diets of college students.which was 4.86±1.72mg.Considering all the potential sources of natural aluminum in foods.water and the individual habitual food,it would apear that most residents in Tianjin would consume 3-10mg aluminum daily from natural dietary sources.

  4. Southwest Aluminum Increase Two Production Lines and May Become the Largest Aluminum Fabricator In the World

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Recently,Wu Bing,Director of Chongqing Economic Committee,announced at the"Industrial Economy Meeting"that the city will"facilitate the technical upgrade and capacity expansion of the existing production lines at Southwest Aluminum with great efforts on the construction of one additional hot continuous rolling line and one cold continuous rolling line so as to have a comprehensive production ca- pacity of 1.2 million tons on aluminum processing profiles for the achievement of building Southwest Aluminum into the world largest aluminum processing enterprise".

  5. Over-heated Investment in Aluminum Hub Industry

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>Aluminum hub is one of typical products with the comparative advantages.China’s aluminum hub industry is very competitive.In recent years,the value of export for the aluminum hub soared,increasing from USD130 millions in 1999 up to nearly USD1 billion in 2004.The main exporter are Wanfeng Auto Holding Group,Shanghai Fervent Alloy Wheel MFG Co.,Ltd.,Nanhai Zhongnan Aluminum Co., Ltd.,Taian Huatai Aluminum Hub Co.,Ltd.

  6. Aluminum speeds up the hydrothermal alteration of olivine

    Science.gov (United States)

    Andreani, Muriel; Daniel, Isabelle; Pollet-Villard, Marion

    2014-05-01

    The reactivity of ultramafic rocks toward hydrothermal fluids controls chemical fluxes at the interface between the internal and external reservoirs of silicate planets. On Earth, hydration of ultramafic rocks is ubiquitous and operates from deep subduction zones to shallow lithospheric environments where it considerably affects the physical and chemical properties of rocks and can interact with the biosphere. This process also has key emerging societal implications, such as the production of hydrogen as a source of carbon-free energy. To date, the chemical model systems used to reproduce olivine hydrothermal alteration lead to the formation of serpentine with sluggish reaction rates. Although aluminum is common in geological environments and in hydrothermal systems in particular, its role in serpentinization or olivine dissolution has not been investigated under hydrothermal conditions. Nevertheless, abundant Al supply is expected in fluids released from dehydration of metapelites in subduction zones as well as during the hydrothermal alteration of gabbros at mid-ocean ridges. Aluminum was also abundant in primitive environments of both the Earth and Mars, stored in either Al-rich minerals like plagioclase or Al-enriched ultramafic lavas. We have investigated the role of Al on the hydrothermal alteration of olivine in a series of experiments performed in a low-pressure diamond anvil cell while following the reaction progress in situ by optical imaging and Raman spectroscopy. Experiments were run for 4.5 to 7.5 days with two olivine grains reacted in saline water (0.5 molal NaCl) at 200°C and 300°C, and P=200 MPa. After two days, olivine crystals were fully transformed to an aluminous serpentine, also enriched in iron. The presence of Al in the hydrothermal fluid increases the rate of olivine serpentinization by more than one order of magnitude by enhancing olivine solubility and serpentine precipitation. The mechanism responsible for this increased solubility

  7. Aluminum-CNF Lightweight Radiator Components Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal relates to a new materials concept for an aluminum-carbon nanofiber composite, high thermal conductivity ultra lightweight material that will form the...

  8. Profit of Aluminum Industry Dropped Sharply

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>On August 2nd,the Ministry of Industry and Information Technology published the performance of nonferrous metal industry in the first half of 2011.Relevant data showed that due to cost increase,aluminum smelting enter

  9. Inhibition of aluminum corrosion using Opuntia extract

    Energy Technology Data Exchange (ETDEWEB)

    El-Etre, A.Y

    2003-11-01

    The inhibitive action of the mucilage extracted from the modified stems of prickly pears, toward acid corrosion of aluminum, is tested using weight loss, thermometry, hydrogen evolution and polarization techniques. It was found that the extract acts as a good corrosion inhibitor for aluminum corrosion in 2.0 M HCl solution. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm. It was found that the adsorption of the extract on aluminum surface is a spontaneous process. The inhibition efficiency (IE) increases as the extract concentration is increased. The effect of temperature on the IE was studied. It was found that the presence of extract increases the activation energy of the corrosion reaction. Moreover, the thermodynamic parameters of the adsorption process were calculated. It was found also that the Opuntia extract provides a good protection to aluminum against pitting corrosion in chloride ion containing solutions.

  10. Aluminum plasmonic multicolor meta-hologram.

    Science.gov (United States)

    Huang, Yao-Wei; Chen, Wei Ting; Tsai, Wei-Yi; Wu, Pin Chieh; Wang, Chih-Ming; Sun, Greg; Tsai, Din Ping

    2015-05-13

    We report a phase-modulated multicolor meta-hologram (MCMH) that is polarization-dependent and capable of producing images in three primary colors. The MCMH structure is made of aluminum nanorods that are arranged in a two-dimensional array of pixels with surface plasmon resonances in red, green, and blue. The aluminum nanorod array is patterned on a 30 nm thick SiO2 spacer layer sputtered on top of a 130 nm thick aluminum mirror. With proper design of the structure, we obtain resonances of narrow bandwidths to allow for implementation of the multicolor scheme. Taking into account of the wavelength dependence of the diffraction angle, we can project images to specific locations with predetermined size and order. With tuning of aluminum nanorod size, we demonstrate that the image color can be continuously varied across the visible spectrum.

  11. Masking of aluminum surface against anodizing

    Science.gov (United States)

    Crawford, G. B.; Thompson, R. E.

    1969-01-01

    Masking material and a thickening agent preserve limited unanodized areas when aluminum surfaces are anodized with chromic acid. For protection of large areas it combines well with a certain self-adhesive plastic tape.

  12. Shock wave compression behavior of aluminum foam

    Institute of Scientific and Technical Information of China (English)

    程和法; 黄笑梅; 薛国宪; 韩福生

    2003-01-01

    The shock wave compression behavior of the open cell aluminum foam with relative density of 0. 396 was studied through planar impact experiments. Using polyvinylidene fluoride(PVDF) piezoelectric gauge technique, the stress histories and propagation velocities of shock wave in the aluminum foam were measured and analyzed. The results show that the amplitude of shock wave attenuates rapidly with increasing the propagation distance in the aluminum foam, and an exponential equation of the normalized peak stress vs propagation distance of shock wave is established, the attenuation factor in the equation is 0. 286. Furthermore, the Hugoniot relation, νs = 516.85+ 1.27νp,for the aluminum foam is determined by empirical fit to the experimental Hugoniot data.

  13. China Aluminum Processing Industry Development Report 2011

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>In 2011,China’s aluminum processing industry maintained a high growth rate,with the aluminum output reaching 23,456,000tons,up 20.6% y-o-y.Overshadowed by complicated situation both at home and abroad,China’seconomy slowed down and declined by2.2% y-o-y.In 2011,China’s aluminum processing industry showed a downward tendency,that is,it grew at a high speed before the3rd quarter,but suffered from a shortage of orders in the remaining time of the year and the growth rate fell increasingly.Between January and August,China’s aluminum output rose by 26% y-o-y;

  14. Stability and Elasticity of High Iron and Aluminum Post-Perovskite Phases and Their Implications for the D" Layer

    Science.gov (United States)

    Shieh, S. R.; Duffy, T. S.; Kubo, A.; Prakapenka, V. B.

    2008-12-01

    To evaluate the iron and aluminum effects on the post-perovskite phase at deep mantle conditions, it is important to study the potential mantle silicates containing both iron and aluminum. In this study, three different compositions of natural garnet along pyrope-almandine join, Pyr21Alm73Gr5, Pyr43Alm54Gr2, Pyr58Alm38Gr3, were used as starting materials to investigate the stability and elasticity of high iron- and aluminum-bearing post-perovskite phase at deep mantle conditions. In situ high-pressure and high- temperature experiments were conducted at beamline 13-ID-D of GSECARS, Advanced Photon Source. A monochromatic beam with a wavelength of 0.3044 Å and a MAR CCD detector were used for X-ray diffraction data collections. Samples were loaded in the symmetrical diamond-anvil cells and heated by the double-sided laser heating system. Our results showed that the post-perovskite phase can be successfully synthesized from three different compositions at pressure greater than 160 GPa and temperature higher than 1600 K. This indicates that the post-perovskite phase can simultaneously accommodate high aluminum and high iron contents. However, Al2O3-post-perovskite phase can also be observed from some runs for Pyr43Alm54Gr2 and Pyr58Alm38Gr3, showing that there is actually a limit for incorporating the aluminum into the post-perovskite phase but not for iron. In addition, we also found that the volume of post- perovskite phases can also be affected by the incorporated amount of iron. Our pressure-volume results showed that high-iron post-perovskite phases have larger volumes and the iron effect is greater at pressure above 120 GPa.

  15. Advanced powder metallurgy aluminum alloys and composites

    Science.gov (United States)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  16. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T(e and N(e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T(e and N(e for the aluminum in aluminum alloys using an optical fiber probe.

  17. Fast LIBS Identification of Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Tawfik W.

    2007-04-01

    Full Text Available Laser-induced breakdown spectroscopy (LIBS has been applied to analysis aluminum alloy targets. The plasma is generated by focusing a 300 mJ pulsed Nd: YAG laser on the target in air at atmospheric pressure. Such plasma emission spectrum was collected using a one-meter length wide band fused-silica optical fiber connected to a portable Echelle spectrometer with intensified CCD camera. Spectroscopic analysis of plasma evolution of laser produced plasmas has been characterized in terms of their spectra, electron density and electron temperature assuming the LTE and optically thin plasma conditions. The LIBS spectrum was optimized for high S/N ratio especially for trace elements. The electron temperature and density were determined using the emission intensity and stark broadening, respectively, of selected aluminum spectral lines. The values of these parameters were found to change with the aluminum alloy matrix, i.e. they could be used as a fingerprint character to distinguish between different aluminum alloy matrices using only one major element (aluminum without needing to analysis the rest of elements in the matrix. Moreover, It was found that the values of T e and N e decrease with increasing the trace elements concentrations in the aluminum alloy samples. The obtained results indicate that it is possible to improve the exploitation of LIBS in the remote on-line industrial monitoring application, by following up only the values of T e and N e for aluminum in aluminum alloys as a marker for the correct alloying using an optical fiber probe.

  18. Transfer and transport of aluminum in filtration unit

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Aluminum salt coagulants were used prevalently in various water works. In this article, the effects of filtration on residual aluminum concentration and species distribution were researched by determining the concentration of different Aluminum species before and after single layer filter, double layer filter, and membrane filtration units. In the research, size exclusion chromatography (SEC) was used to separate colloidal and soluble aluminum, ion exchange chromatography (IEC) was used to separate organic and inorganic aluminum, and inductivity coupled plasma-atomic emission spectrometry (ICP-AES) was used to determine the aluminum concentration. The results showed that the rapid filtration process had the ability of removing residual aluminum from coagulant effluent water, and that double layer filtration was more effective in residual aluminum removal than single layer filtration, while Nano filtration was more effective than micro filtration. It was found that when the residual aluminum concentration was below 1mg/L in sediment effluent, the residual aluminum concentration in treated water was above 0.2 mg/L. The direct rapid filtration process mainly removed the suspended aluminum. The removal of soluble and colloidal aluminum was always less than 10% and the natural small particles that adsorbed the amount of soluble or small particles aluminum on their surface were difficult to be removed in this process. Micro filtration and nano filtration were good technologies for removing aluminum; the residual aluminum concentration in the effluent was less than 0.05 mg/L.

  19. Studies of aluminum in rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Lipman, J.J.; Brill, A.B.; Som, P.; Jones, K.W.; Colowick, S.; Cholewa, M.

    1985-01-01

    The effects of high aluminum concentrations in rat brains were studied using /sup 14/C autoradiography to measure the uptake of /sup 14/C 2-deoxy-D-glucose (/sup 14/C-2DG) and microbeam proton-induced x-ray emission (microPIXE) with a 20-..mu..m resolution to measure concentrations of magnesium, aluminum, potassium, and calcium. The aluminum was introduced intracisternally in the form of aluminum tartrate (Al-T) while control animals were given sodium tartrate (Na-T). The /sup 14/C was administered intravenously. The animals receiving Al-T developed seizure disorders and had pathological changes that included cerebral cortical atrophy. The results showed that there was a decreased uptake of /sup 14/C-2DG in cortical regions in which increased aluminum levels were measured, i.e., there is a correlation between the aluminum in the rat brain and decreased brain glucose metabolism. A minimum detection limit of about 16 ppM (mass fraction) or 3 x 10/sup 9/ Al atoms was obtained for Al under the conditions employed. 14 refs., 4 figs., 1 tab.

  20. The silicate absorption profile in the ISM towards the heavily obscured nucleus of NGC 4418

    CERN Document Server

    Roche, P F; Gonzalez-Martin, O

    2015-01-01

    The 9.7-micron silicate absorption profile in the interstellar medium provides important information on the physical and chemical composition of interstellar dust grains. Measurements in the Milky Way have shown that the profile in the diffuse interstellar medium is very similar to the amorphous silicate profiles found in circumstellar dust shells around late M stars, and narrower than the silicate profile in denser star-forming regions. Here, we investigate the silicate absorption profile towards the very heavily obscured nucleus of NGC 4418, the galaxy with the deepest known silicate absorption feature, and compare it to the profiles seen in the Milky Way. Comparison between the 8-13 micron spectrum obtained with TReCS on Gemini and the larger aperture spectrum obtained from the Spitzer archive indicates that the former isolates the nuclear emission, while Spitzer detects low surface brightness circumnuclear diffuse emission in addition. The silicate absorption profile towards the nucleus is very similar to...

  1. Analyses of Cometary Silicate Crystals: DDA Spectral Modeling of Forsterite

    Science.gov (United States)

    Wooden, Diane

    2012-01-01

    Comets are the Solar System's deep freezers of gases, ices, and particulates that were present in the outer protoplanetary disk. Where comet nuclei accreted was so cold that CO ice (approximately 50K) and other supervolatile ices like ethane (C2H2) were preserved. However, comets also accreted high temperature minerals: silicate crystals that either condensed (greater than or equal to 1400 K) or that were annealed from amorphous (glassy) silicates (greater than 850-1000 K). By their rarity in the interstellar medium, cometary crystalline silicates are thought to be grains that formed in the inner disk and were then radially transported out to the cold and ice-rich regimes near Neptune. The questions that comets can potentially address are: How fast, how far, and over what duration were crystals that formed in the inner disk transported out to the comet-forming region(s)? In comets, the mass fractions of silicates that are crystalline, f_cryst, translate to benchmarks for protoplanetary disk radial transport models. The infamous comet Hale-Bopp has crystalline fractions of over 55%. The values for cometary crystalline mass fractions, however, are derived assuming that the mineralogy assessed for the submicron to micron-sized portion of the size distribution represents the compositional makeup of all larger grains in the coma. Models for fitting cometary SEDs make this assumption because models can only fit the observed features with submicron to micron-sized discrete crystals. On the other hand, larger (0.1-100 micrometer radii) porous grains composed of amorphous silicates and amorphous carbon can be easily computed with mixed medium theory wherein vacuum mixed into a spherical particle mimics a porous aggregate. If crystalline silicates are mixed in, the models completely fail to match the observations. Moreover, models for a size distribution of discrete crystalline forsterite grains commonly employs the CDE computational method for ellipsoidal platelets (c:a:b=8

  2. Sealing of cracks in cement using microencapsulated sodium silicate

    Science.gov (United States)

    Giannaros, P.; Kanellopoulos, A.; Al-Tabbaa, A.

    2016-08-01

    Cement-based materials possess an inherent autogenous self-healing capability allowing them to seal, and potentially heal, microcracks. This can be improved through the addition of microencapsulated healing agents for autonomic self-healing. The fundamental principle of this self-healing mechanism is that when cracks propagate in the cementitious matrix, they rupture the dispersed capsules and their content (cargo material) is released into the crack volume. Various healing agents have been explored in the literature for their efficacy to recover mechanical and durability properties in cementitious materials. In these materials, the healing agents are most commonly encapsulated in macrocontainers (e.g. glass tubes or capsules) and placed into the material. In this work, microencapsulated sodium silicate in both liquid and solid form was added to cement specimens. Sodium silicate reacts with the calcium hydroxide in hydrated cement paste to form calcium-silicate-hydrate gel that fills cracks. The effect of microcapsule addition on rheological and mechanical properties of cement is reported. It is observed that the microcapsule addition inhibits compressive strength development in cement and this is observed through a plateau in strength between 28 and 56 days. The improvement in crack-sealing for microcapsule-containing specimens is quantified through sorptivity measurements over a 28 day healing period. After just seven days, the addition of 4% microcapsules resulted in a reduction in sorptivity of up to 45% when compared to specimens without any microcapsule addition. A qualitative description of the reaction between the cargo material and the cementitious matrix is also provided using x-ray diffraction analysis.

  3. SILICATES ON IAPETUS FROM CASSINI’S COMPOSITE INFRARED SPECTROMETER

    Energy Technology Data Exchange (ETDEWEB)

    Young, Cindy L.; Wray, James J. [School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA (United States); Clark, Roger N. [Planetary Science Institute, Tucson, AZ (United States); Spencer, John R. [Southwest Research Institute, Boulder, CO (United States); Jennings, Donald E. [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Hand, Kevin P.; Carlson, Robert W. [Jet Propulsion Laboratory, Pasadena, CA (United States); Poston, Michael J. [Caltech, Pasadena, CA (United States)

    2015-10-01

    We present the first spectral features obtained from Cassini’s Composite Infrared Spectrometer (CIRS) for any icy moon. The spectral region covered by CIRS focal planes (FP) 3 and 4 is rich in emissivity features, but previous studies at these wavelengths have been limited by low signal-to-noise ratios (S/Ns) for individual spectra. Our approach is to average CIRS FP3 spectra to increase the S/N and use emissivity spectra to constrain the composition of the dark material on Iapetus. We find an emissivity feature at ∼855 cm{sup −1} and a possible doublet at 660 and 690 cm{sup −1} that do not correspond to any known instrument artifacts. We attribute the 855 cm{sup −1} feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths. Silicates on the dark terrains of Saturn’s icy moons have been suspected for decades, but there have been no definitive detections until now. Serpentines reported in the literature at ambient temperature and pressure have features near 855 and 660 cm{sup −1}. However, peaks can shift depending on temperature and pressure, so measurements at Iapetus-like conditions are necessary for more positive feature identifications. As a first investigation, we measured muscovite at 125 K in a vacuum and found that this spectrum does match the emissivity feature near 855 cm{sup −1} and the location of the doublet. Further measurements are needed to robustly identify a specific silicate, which would provide clues regarding the origin and implications of the dark material.

  4. Geoengineering potential of artificially enhanced silicate weathering of olivine.

    Science.gov (United States)

    Köhler, Peter; Hartmann, Jens; Wolf-Gladrow, Dieter A

    2010-11-23

    Geoengineering is a proposed action to manipulate Earth's climate in order to counteract global warming from anthropogenic greenhouse gas emissions. We investigate the potential of a specific geoengineering technique, carbon sequestration by artificially enhanced silicate weathering via the dissolution of olivine. This approach would not only operate against rising temperatures but would also oppose ocean acidification, because it influences the global climate via the carbon cycle. If important details of the marine chemistry are taken into consideration, a new mass ratio of CO(2) sequestration per olivine dissolution of about 1 is achieved, 20% smaller than previously assumed. We calculate that this approach has the potential to sequestrate up to 1 Pg of C per year directly, if olivine is distributed as fine powder over land areas of the humid tropics, but this rate is limited by the saturation concentration of silicic acid. In our calculations for the Amazon and Congo river catchments, a maximum annual dissolution of 1.8 and 0.4 Pg of olivine seems possible, corresponding to the sequestration of 0.5 and 0.1 Pg of C per year, but these upper limit sequestration rates come at the environmental cost of pH values in the rivers rising to 8.2. Open water dissolution of fine-grained olivine and an enhancement of the biological pump by the rising riverine input of silicic acid might increase our estimate of the carbon sequestration, but additional research is needed here. We finally calculate with a carbon cycle model the consequences of sequestration rates of 1-5 Pg of C per year for the 21st century by this technique.

  5. Low-(18)O Silicic Magmas: Why Are They So Rare?

    Energy Technology Data Exchange (ETDEWEB)

    Balsley, S.D.; Gregory, R.T.

    1998-10-15

    LOW-180 silicic magmas are reported from only a small number of localities (e.g., Yellowstone and Iceland), yet petrologic evidence points to upper crustal assimilation coupled with fractional crystallization (AFC) during magma genesis for nearly all silicic magmas. The rarity of 10W-l `O magmas in intracontinental caldera settings is remarkable given the evidence of intense 10W-l*O meteoric hydrothermal alteration in the subvolcanic remnants of larger caldera systems. In the Platoro caldera complex, regional ignimbrites (150-1000 km3) have plagioclase 6180 values of 6.8 + 0.1%., whereas the Middle Tuff, a small-volume (est. 50-100 km3) post-caldera collapse pyroclastic sequence, has plagioclase 8]80 values between 5.5 and 6.8%o. On average, the plagioclase phenocrysts from the Middle Tuff are depleted by only 0.3%0 relative to those in the regional tuffs. At Yellowstone, small-volume post-caldera collapse intracaldera rhyolites are up to 5.5%o depleted relative to the regional ignimbrites. Two important differences between the Middle Tuff and the Yellowstone 10W-180 rhyolites elucidate the problem. Middle Tuff magmas reached water saturation and erupted explosively, whereas most of the 10W-l 80 Yellowstone rhyolites erupted effusively as domes or flows, and are nearly devoid of hydrous phenocrysts. Comparing the two eruptive types indicates that assimilation of 10W-180 material, combined with fractional crystallization, drives silicic melts to water oversaturation. Water saturated magmas either erupt explosively or quench as subsurface porphyrins bejiire the magmatic 180 can be dramatically lowered. Partial melting of low- 180 subvolcanic rocks by near-anhydrous magmas at Yellowstone produced small- volume, 10W-180 magmas directly, thereby circumventing the water saturation barrier encountered through normal AFC processes.

  6. Conduction mechanism in bismuth silicate glasses containing titanium

    Science.gov (United States)

    Dult, Meenakshi; Kundu, R. S.; Murugavel, S.; Punia, R.; Kishore, N.

    2014-11-01

    Bismuth silicate glasses mixed with different concentrations of titanium dioxide having compositions xTiO2-(60-x)Bi2O3-40SiO2 with x=0, 5, 10, 15 and 20 were prepared by the normal melt quench technique. The frequency dependence of the ac electrical conductivity of different compositions of titanium bismuth silicate glasses has been studied in the frequency range 10-1 Hz to 10 MHz and in the temperature range 623-703 K. The temperature and frequency dependent conductivity is found to obey Jonscher's universal power law for all the compositions of titanium bismuth silicate glass system. The dc conductivity (σdc), so called crossover frequency (ωH), and frequency exponent (s) have been estimated from the fitting of experimental data of ac conductivity with Jonscher's universal power law. Enthalpy to dissociate the cation from its original site next to a charge compensating center (Hf) and enthalpy of migration (Hm) have also been estimated. The conductivity data have been analyzed in terms of different theoretical models to determine the possible conduction mechanism. Analysis of the conductivity data and the frequency exponent shows that the correlated barrier hopping of electrons between Ti3+ and Ti4+ ions in the glasses is the most favorable mechanism for ac conduction. The temperature dependent dc conductivity has been analyzed in the framework of theoretical variable range hopping model (VRH) proposed by Mott which describe the hopping conduction in disordered semiconducting systems. The various polaron hopping parameters have also been deduced. Mott's VRH model is found to be in good agreement with experimental data and the values of inverse localization length of s-like wave function (α) obtained by this model with modifications suggested by Punia et al. are close to the ones reported for a number of oxide glasses.

  7. Nanostructures Using Anodic Aluminum Oxide

    Science.gov (United States)

    Valmianski, Ilya; Monton, Carlos M.; Pereiro, Juan; Basaran, Ali C.; Schuller, Ivan K.

    2013-03-01

    We present two fabrication methods for asymmetric mesoscopic dot arrays over macroscopic areas using anodic aluminum oxide templates. In the first approach, metal is deposited at 45o to the template axis to partially close the pores and produce an elliptical shadow-mask. In the second approach, now underway, nanoimprint lithography on a polymer intermediary layer is followed by reactive ion etching to generate asymmetric pore seeds. Both these techniques are quantified by an analysis of the lateral morphology and lattice of the pores or dots using scanning electron microscopy and a newly developed MATLAB based code (available for free download at http://ischuller.ucsd.edu). The code automatically provides a segmentation of the measured area and the statistics of morphological properties such as area, diameter, and eccentricity, as well as the lattice properties such as number of nearest neighbors, and unbiased angular and radial two point correlation functions. Furthermore, novel user defined statistics can be easily obtained. We will additionally present several applications of these methods to superconducting, ferromagnetic, and organic nanostructures. This work is supported by AFOSR FA9550-10-1-0409

  8. Effect of Process Parameters on Porosity in Aluminum Lost Foam Process

    Institute of Scientific and Technical Information of China (English)

    Kiyoung KIM; Kyongwhoan LEE

    2005-01-01

    Porosity is a main defect in aluminum alloy castings, which is also thought to be severe in aluminum alloy castings produced by lost foam process due to the pyrolysis of the polystyrene foam pattern during pouring. Fundamental experiments were carried out to evaluate the effect of process parameters such as the melt treatment, the cooling rate and the density of expanded polystyrene (EPS) foam on porosity in A356.2 bar casting. The effect of melt treatment including degassing and refining was investigated. The effect of cooling rate was also evaluated by changing the mold packing material such as the silica sand, the zircon sand and the steel shots. Gas entrapment due to the turbulent metal flow during mold filling in conventional molding process results in porosity. Mold filling sequence in lost foam process is different from that in conventional molding process. The effect of molten metal flow was estimated by comparing the density of the casting by conventional sodium silicate molding with that by lost foam process. Density measurement was conducted to analyze the extent of porosity in the casting. Source of the porosity in lost foam process can be divided into two factors, i.e. turbulence in molten metal flow and entraining residue or gas from the pattern during pouring.

  9. In vitro bioactivity and cytocompatibility of tricalcium silicate

    Indian Academy of Sciences (India)

    Xiaoming Liao; Hongyang Zhu; Guangfu Yin; Zhongbing Huang; Yadong Yao; Xianchun Chen

    2011-08-01

    The in vitro bioactivity of tricalcium silicate (Ca3SiO5) ceramics was investigated by the bone-like apatite-formation ability in simulated body fluid (SBF), and the cytocompatibility was evaluated through osteoblast adhesion and proliferation assay. The results show that the Ca3SiO5 ceramics possess bone-like apatite formation ability in SBF. In vitro cytocompatible evaluation reveals that osteoblasts adhere and spread well on the Ca3SiO5 ceramics, indicating good bioactivity and cytocompatibility.

  10. Cracking phenomena in lithium-di-silicate glass ceramics

    Indian Academy of Sciences (India)

    Rajat Banerjee

    2001-04-01

    Lithium-di-silicate glass ceramic (Li2O, SiO2) with uniformly oriented crystals was placed on a Vickers indentation with extrusion axis horizontally parallel to the base axis. The material was rotated through 0°– 90° and at each angle a 20 N load was applied to ascertain the crack path. It was observed that the crack length decreases and the crack deviates from its original path with increasing angle. The deviation of the crack was correlated with the component of the crack driving force and the theoretical strength of the aligned crystals at different angles.

  11. Concentration Quenching in Erbium Doped Bismuth Silicate Glasses

    Institute of Scientific and Technical Information of China (English)

    DAI Shi-Xun; XU Tie-Feng; NIE Qiu-Hua; SHEN Xiang; WANG Xun-Si

    2006-01-01

    @@ Er2 O3-doped bismuth silicate glasses are prepared by the conventional melt-quenching method, and the Er3+ : 4 I13/2 → 4I15/2 fluorescence properties are studied for different Er3+ concentrations. Infrared spectra are measured to estimate the exact content of OH- groups in the samples. Based on the electric dipole-dipole interaction theory,the interaction parameter CEr,Er for the migration rate of Er3+ :4 I13/2 → 4 I13/2 in proposed glasses is calculated.

  12. Kinetics of Cyclohexanone Ammoximation over Titanium Silicate Molecular Sieves

    Institute of Scientific and Technical Information of China (English)

    李永祥; 吴巍; 闵恩泽

    2005-01-01

    An intrinsic kinetics of cyclohexanone ammoximation in the liquid phase over titanium silicate molecular sieves is investigated in an isothermal slurry reactor at different initial reactant concentrations, catalyst loading,and reaction temperature. The rate equations are developed by analyzing data of kinetic measurements. More than 10 side reactions were found. H202 decomposition reaction Inust be considered and other side reactions can be neglected in the kinetic modeling. The predicted values of reaction rates based on the kinetic models are almost consistent with experimental ones. The models have guidance to the selection of reactor types and they are useful to the design and operation of reactor used.

  13. Transparent silicate glass-ceramics embedding Ni-doped nanocrystals

    OpenAIRE

    2010-01-01

    Recent progress in the development of transparent silicate glass-ceramics embedding Ni-doped nanocrystals as broadband gain media is reviewed. At first, optical properties such as the peak positions, wavelengths lifetimes and quantum efficiencies of the near-infrared emission of nickel-doped oxide crystals are overviewed. The quantum efficiencies of the near-infrared emission of nickel-doped LiGa5O8 and MgGa2O4 were as high as ~1 even at room temperature. Thus these materials are promising ca...

  14. U.S. Geological Survey silicate rock standards

    Science.gov (United States)

    Flanagan, F.J.

    1967-01-01

    The U.S. Geological Survey has processed six silicate rocks to provide new reference samples to supplement G-1 and W-1. Complete conventional, rapid rock, and spectrochemical analyses by the U.S. Geological Survey are reported for a granite (replacement for G-1), a granodiorite, an andesite, a peridotite, a dunite, and a basalt. Analyses of variance for nickel, chromium, copper, and zirconium in each rock sample showed that for these elements, the rocks can be considered homogeneous. Spectrochemical estimates are given for the nickel, chromium, copper, and zirconium contents of the samples. The petrography of five of the six rocks is described and CIPW norms are presented. ?? 1967.

  15. Infrared Spectroscopy and Stable Isotope Geochemistry of Hydrous Silicate Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Stolper, Edward

    2007-03-05

    The focus of this DOE-funded project has been the study of volatile components in magmas and the atmosphere. Over the twenty-one year period of this project, we have used experimental petrology and stable isotope geochemistry to study the behavior and properties of volatile components dissolved in silicate minerals and melts and glasses. More recently, we have also studied the concentration and isotopic composition of CO2 in the atmosphere, especially in relation to air quality issues in the Los Angeles basin.

  16. Ultra flat supercontinuum generation in silicate dual core microstructured fiber

    Science.gov (United States)

    Buczynski, R.; Pysz, D.; Martynkien, T.; Lorenc, D.; Kujawa, I.; Nasilowski, T.; Berghmans, F.; Thienpont, H.; Stepien, R.

    2009-08-01

    In this paper we report on ultra flat supercontinuum generation in dual core photonic crystal fiber pumped in the normal dispersion regime. The fiber cladding is fabricated from custom NC21 borosilicate glass while the fiber cores is made of commercially available F2 high index lead-silicate glass from Schott Corp. We investigated the supercontinuum characteristics for single and double core excitation by a Ti:Sapphire oscillator delivering 100 fs pulses centered at 800 nm with an energy of 4.2 nJ. Dual core pumping resulted in appreciable flattening of the supercontinuum spectra in the range 875 - 950 nm.

  17. High-temperature silicate volcanism on Jupiter's moon Io.

    Science.gov (United States)

    McEwen, A S; Keszthelyi, L; Spencer, J R; Schubert, G; Matson, D L; Lopes-Gautier, R; Klaasen, K P; Johnson, T V; Head, J W; Geissler, P; Fagents, S; Davies, A G; Carr, M H; Breneman, H H; Belton, M J

    1998-07-03

    Infrared wavelength observations of Io by the Galileo spacecraft show that at least 12 different vents are erupting lavas that are probably hotter than the highest temperature basaltic eruptions on Earth today. In at least one case, the eruption near Pillan Patera, two independent instruments on Galileo show that the lava temperature must have exceeded 1700 kelvin and may have reached 2000 kelvin. The most likely explanation is that these lavas are ultramafic (magnesium-rich) silicates, and this idea is supported by the tentative identification of magnesium-rich orthopyroxene in lava flows associated with these high-temperature hot spots.

  18. Ladinian radiolarian fauna, siliceous rock from the Xianshuihe Belt, West Sichuan and their tectonic significance

    Institute of Scientific and Technical Information of China (English)

    LIANG Bin; FENG Qinglai; WANG Quanwei; GUO Jianqiu; ZHONG Changhong; LI Zhenjiang

    2005-01-01

    Ladinian radiolarian fauna, including Muelleritortis, Baumgartneria, Oertlispongus,Paroertlispongus, Pseudoertlispongus, etc., was discovered from the siliceous rock of the Runiange Formation in the Xianshuihe belt, West Sichuan Province. Geochemical test on five samples from the siliceous rock indicates that SiO2 content varies in 71.16%-90.06% and Si/Al ratio, in 49-71, which shows that the siliceous rock contains more terrigenous mud sediments.The siliceous rock is characterized by the large ratios of Al203/(Al203+Fe203) (0.63-0.81) and TiN (>26), the low ratio of V/Y (<2.8), and low vanadium content (<23 μg/g), which are similar to the geochemical characteristics of continental margin siliceous rock. The Ce/Ce* ratios of the four samples vary in 1.02-1.47 and the LaN/CeN ratio, in 0.75-1.07, which imply that the siliceous rock was deposited in the continental margin basin. But only one sample is similar to the oceanic siliceous rock in REE. Turbidite-siliceous rock bearing radiolarian-basalt assemblage and the geochemical characteristics of the siliceous rock indicate that the Xianshuihe belt is in the strong rift stage in the Ladinian age.

  19. Studying regimes of convective heat transfer in the production of high-temperature silicate melts

    Science.gov (United States)

    Volokitin, O. G.; Sheremet, M. A.; Shekhovtsov, V. V.; Bondareva, N. S.; Kuzmin, V. I.

    2016-09-01

    The article presents the results of theoretical and experimental studies of the production of high-temperature silicate melts using the energy of low-temperature plasma in a conceptually new setup. A mathematical model of unsteady regimes of convective heat and mass transfer is developed and numerically implemented under the assumption of non-Newtonian nature of flow in the melting furnace with plasma-chemical synthesis of high-temperature silicate melts. Experiments on melting silicate containing materials were carried out using the energy of low-temperature plasma. The dependence of dynamic viscosity of various silicate materials (basalt, ash, waste of oil shale) was found experimentally.

  20. Lack of marked cyto- and genotoxicity of cristobalite in devitrified (heated) alkaline earth silicate wools in short-term assays with cultured primary rat alveolar macrophages.

    Science.gov (United States)

    Ziemann, Christina; Harrison, Paul T C; Bellmann, Bernd; Brown, Robert C; Zoitos, Bruce K; Class, Philippe

    2014-02-01

    Alkaline earth silicate (AES) wools are low-biopersistence high-temperature insulation wools. Following prolonged periods at high temperatures they may devitrify, producing crystalline silica (CS) polymorphs, including cristobalite, classified as carcinogenic to humans. Here we investigated the cytotoxic and genotoxic significance of cristobalite present in heated AES wools. Primary rat alveolar macrophages were incubated in vitro for 2 h with 200 µg/cm² unheated/heated calcium magnesium silicate wools (CMS1, CMS2, CMS3; heat-treated for 1 week at, or 4 weeks 150 °C below, their respective classification temperatures) or magnesium silicate wool (MS; heated for 24 h at 1260 °C). Types and quantities of CS formed, and fiber size distribution and shape were determined by X-ray diffraction and electron microscopy. Lactate dehydrogenase release and alkaline and hOGG1-modified comet assays were used, ± aluminum lactate (known to quench CS effects), for cytotoxicity/genotoxicity screening. Cristobalite content of wools increased with heating temperature and duration, paralleled by decreases in fiber length and changes in fiber shape. No marked cytotoxicity, and nearly no (CMS) or only slight (MS) DNA-strand break induction was observed, compared to the CS-negative control Al₂O₃, whereas DQ12 as CS-positive control was highly active. Some samples induced slight oxidative DNA damage, but no biological endpoint significantly correlated with free CS, quartz, or cristobalite. In conclusion, heating of AES wools mediates changes in CS content and fiber length/shape. While changes in fiber morphology can impact biological activity, cristobalite content appears minor or of no relevance to the intrinsic toxicity of heated AES wools in short-term assays with rat alveolar macrophages.

  1. Anodized aluminum on LDEF: A current status of measurements on chromic acid anodized aluminum

    Science.gov (United States)

    Golden, Johnny L.

    1992-01-01

    Chromic acid anodize was used as the exterior coating for aluminum surfaces on LDEF to provide passive thermal control. Chromic acid anodized aluminum was also used as test specimens in thermal control coatings experiments. The following is a compilation and analysis of the data obtained thus far.

  2. Deposition of aluminum-magnesium alloys from electrolytes containing organo-aluminum complexes

    Energy Technology Data Exchange (ETDEWEB)

    Lehmkuhl, H.; Mehler, K.; Bongard, H.; Tesche, B. [Max-Planck-Inst. fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Reinhold, B. [Audi AG Technische Entwicklung, Ingolstadt (Germany)

    2001-06-01

    Organo-aluminum compounds have been used for many years as electrolytes in the coating industry. In this communication the development of a galvanic process for generating aluminum-magnesium coatings from organometallic electrolyte systems is reported as well as results on physical properties like adhesion, ductility and corrosion resistance. (orig.)

  3. Structure and aqueous reactivity of silicate glasses high-resolution nuclear magnetic resonance contribution; Structure et reactivite aqueuse des verres silicates apport de la resonance magnetique nucleaire haute-resolution

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, F

    2000-10-25

    This research aims at getting a better understanding of the relations which may exist between the chemical composition of the oxide silicate glasses, the structure and the aqueous reactivity. We study the cations present in most glasses, more particularly the radioactive waste glasses, and those which are more liable to bring information both about structure and reactivity. Among the experimental methods used, the nuclear magnetic resonance of multi-quantum magic-angle spinning (NMR MQ-MAS) has been carried out for the structural characterization of the pristine and altered glasses. In the first part, we discuss the possibility of deducting a type of information from a quantitative approach of the {sup 23}Na, {sup 27}Al and {sup 17}O NMR MQ-MAS. In the second part, we apply this method to glasses containing between two and six oxides. The vitreous compositions studied permit to focus our attention on the influence of sodium, aluminum and calcium on their local structural environment. We point out an evolution of the distributions of bond distances and angles in relation to the glass chemical composition. We show the strong potentiality of the {sup 17}O used to probe the pristine and altered glasses. The influence of the different cations studied on the rate of glass dissolution is debated from the alterations made on short periods. On the basis of all these data, we discuss the importance of the structural effect which may influence the kinetic phenomena of alteration. (author)

  4. Aluminum electrocoagulation as pretreatment during microfiltration of surface water containing NOM: A review of fouling, NOM, DBP, and virus control.

    Science.gov (United States)

    Chellam, Shankararaman; Sari, Mutiara Ayu

    2016-03-01

    Electrocoagulation (EC) is the intentional corrosion of sacrificial anodes (typically aluminum or iron) by passing electricity to release metal-ion coagulant species and destabilize a wide range of suspended, dissolved, and macromolecular contaminants. It can be integrated ahead of microfiltration (MF) to effectively control turbidity, microorganisms, and disinfection by-products (DBPs) and simultaneously maintain a high MF specific flux. This manuscript summarizes the current knowledge on MF pretreatment by aluminum EC particularly focusing on mechanisms of (i) electrocoagulant dosing, (ii) (bio)colloid destabilization, (iii) fouling reductions, and (iv) enhanced removal of viruses, natural organic matter (NOM), and DBP precursors. Electrolysis efficiently removes hydrophobic NOM, viruses, and siliceous foulants. Aluminum effectively electrocoagulates viruses by physically encapsulating them in flocs, neutralizing their surface charge and reducing electrostatic repulsion, and increasing hydrophobic interactions between any sorbed NOM and free viruses. New results included herein demonstrate that EC achieves DBP control by removing NOM, reducing chlorine-reactivity of remaining NOM, and inducing a slight shift toward more brominated trihalomethanes and haloacetic acids. EC reduces MF fouling by forming large flocs that tend to deposit on the membrane surface, i.e. decrease pore penetration and forming more permeable cakes and by reducing foulant mass in case of significant floc-flotation.

  5. Polarization properties of real aluminum mirrors; I. Influence of the aluminum oxide layer

    CERN Document Server

    van Harten, G; Keller, C U

    2009-01-01

    In polarimetry it is important to characterize the polarization properties of the instrument itself to disentangle real astrophysical signals from instrumental effects. This article deals with the accurate measurement and modeling of the polarization properties of real aluminum mirrors, as used in astronomical telescopes. Main goals are the characterization of the aluminum oxide layer thickness at different times after evaporation and its influence on the polarization properties of the mirror. The full polarization properties of an aluminum mirror are measured with Mueller matrix ellipsometry at different incidence angles and wavelengths. The best fit of theoretical Mueller matrices to all measurements simultaneously is obtained by taking into account a model of bulk aluminum with a thin aluminum oxide film on top of it. Full Mueller matrix measurements of a mirror are obtained with an absolute accuracy of ~1% after calibration. The determined layer thicknesses indicate logarithmic growth in the first few hou...

  6. Progress in Aluminum Electrolysis Control and Future Direction for Smart Aluminum Electrolysis Plant

    Science.gov (United States)

    Zhang, Hongliang; Li, Tianshuang; Li, Jie; Yang, Shuai; Zou, Zhong

    2016-10-01

    The industrial aluminum reduction cell is an electrochemistry reactor that operates under high temperatures and highly corrosive conditions. However, these conditions have restricted the measurement of key control parameters, making the control of aluminum reduction cells a difficult problem in the industry. Because aluminum electrolysis control systems have a significant economic influence, substantial research has been conducted on control algorithms, control systems and information systems for aluminum reduction cells. This article first summarizes the development of control systems and then focuses on the progress made since 2000, including alumina concentration control, temperature control and electrolyte molecular ratio control, fault diagnosis, cell condition prediction and control system expansion. Based on these studies, the concept of a smart aluminum electrolysis plant is proposed. The frame construction, key problems and current progress are introduced. Finally, several future directions are discussed.

  7. Methods for both coating a substrate with aluminum oxide and infusing the substrate with elemental aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jung-Pyung; Weil, Kenneth Scott

    2016-11-01

    Methods of aluminizing the surface of a metal substrate. The methods of the present invention do not require establishment of a vacuum or a reducing atmosphere, as is typically necessary. Accordingly, aluminization can occur in the presence of oxygen, which greatly simplifies and reduces processing costs by allowing deposition of the aluminum coating to be performed, for example, in air. Embodiments of the present invention can be characterized by applying a slurry that includes a binder and powder granules containing aluminum to the metal substrate surface. Then, in a combined step, a portion of the aluminum is diffused into the substrate and a portion of the aluminum is oxidized by heating the slurry to a temperature greater than the melting point of the aluminum in an oxygen-containing atmosphere.

  8. Enhanced bioactivity of glass ionomer cement by incorporating calcium silicates.

    Science.gov (United States)

    Chen, Song; Cai, Yixiao; Engqvist, Håkan; Xia, Wei

    2016-01-01

    Glass ionomer cements (GIC) are known as a non-bioactive dental cement. During setting the GIC have an acidic pH, driven by the acrylic acid component. It is a challenge to make GIC alkaline without disturbing its mechanical properties. One strategy was to add slowly reacting systems with an alkaline pH. The aim of the present study is to investigate the possibility of forming a bioactive dental material based on the combination of glass ionomer cement and calcium silicates. Two types of GIC were used as control. Wollastonite (CS also denoted β-CaSiO3) or Mineral Trioxide Aggregate (MTA) was incorporated into the 2 types of GIC. The material formulations' setting time, compressive strength, pH and bioactivity were compared between modified GIC and GIC control. Apatite crystals were found on the surfaces of the modified cements but not on the control GIC. The compressive strength of the cement remained with the addition of 20% calcium silicate or 20% MTA after one day immersion. In addition, the compressive strength of GIC modified with 20% MTA had been increased during the 14 d immersion (p < 0 .05).

  9. Identification and Practical Application of Silicate-dissolving Bacteria

    Institute of Scientific and Technical Information of China (English)

    LIN Qi-mei; RAO Zheng-hua; SUN Yan-xing; YAO Jun; XING Li-jun

    2002-01-01

    Slime-forming bacteria were isolated from soils, rock surface and earthworm intestine, and their effects on dissolving silicate minerals and tomato growth were examined. One of the bacteria, Bacillus mucilaginosus RGBc13, had particularly strong ability to form slime and dissolve silicates. RGBc13 could also colonize and develop in both non-rhizosphere and rhizosphere soil. Total number of slime-forming bacteria increased from 2.9 × 103 cfu·g- 1and 8.4 × 103 cfu·g-1 to 9.6 × 106 cfu·g-1 and 6.0 × 107 cfu·g-1 in the non-rhizosphere and rhizosphere soils respectively. Potassium and phosphorus nutritional conditions in the rhizosphere were markedly improved through inoculation of this bacterium. Available K and P respectively increased from 25.86 and 3.63mg· kg-1 in the non-rhizosphere soil to 91.23 and 5.74mg· kg-1 in the rhizosphere soil. Tomato biomass increased by 125%, K and P uptakes were more than 150%, greater than the non- inoculation. Thus, there is a potential in applying RGBc13 for improving plant K and P nutrition.

  10. Ion-specific effects influencing the dissolution of tricalcium silicate

    Energy Technology Data Exchange (ETDEWEB)

    Nicoleau, L. [BASF Research Construction Materials and Systems, BASF Construction Chemicals GmbH, 83308 Trostberg (Germany); Schreiner, E., E-mail: eduard.schreiner@basf.com [BASF Materials and Systems, BASF SE, 67056 Ludwigshafen (Germany); Nonat, A., E-mail: andre.nonat@u-bourgogne.fr [Institut Carnot de Bourgogne, UMR6303 CNRS, 9 avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)

    2014-05-01

    It has been recently demonstrated that the dissolution kinetics of tricalcium silicate (C{sub 3}S) is driven by the deviation from its solubility equilibrium. In this article, special attention is paid to ions relevant in cement chemistry likely to interact with C{sub 3}S. In order to determine whether specific effects occur at the interface C{sub 3}S–water, particular efforts have been made to model ion activities using Pitzer's model. It has been found that monovalent cations and monovalent anions interact very little with the surface of C{sub 3}S. On the other side, divalent anions like sulfate slow down the dissolution more strongly by modifying the surface charging of C{sub 3}S. Third, aluminate ions covalently bind to surface silicate monomers and inhibit the dissolution in mildly alkaline conditions. The formation and the breaking of these bonds depend on pH and on [Ca{sup 2+}]. Thermodynamic calculations performed using DFT combined with the COSMO-RS solvation method support the experimental findings.

  11. Authigenic Mineralization of Silicates at the Organic-water Interface

    Science.gov (United States)

    McEvoy, B.; Wallace, A. F.

    2015-12-01

    It is relatively common for some fraction of organic material to be preserved in the sedimentary rock record as disseminated molecular fragments. The survival of wholly coherent tissues from primarily soft-bodied organisms is far more unusual. However, the literature is now well- populated with spectacular examples of soft-tissue preservation ranging from a 2,600 year old human brain to the tissues of the Ediacaran biota that have survived ~600 million years. Some of the most exceptional examples of soft tissue preservation are from the Proterozoic-Cambrian transition, however, nearly all modes of fossil preservation during this time are debated. Clay mineral templates have been implicated as playing a role in several types of soft tissue preservation, including Burgess Shale and Beecher's Trilobite-type preservation, and more recently, Bitter Springs-type silicification. Yet, there is still much debate over whether these clay mineral coatings form during early stage burial and diagenesis, or later stage metamorphism. This research addresses this question by using in situ fluid cell Atomic Force Microscopy (AFM) to investigate the nucleation and growth of silicate minerals on model biological surfaces. Herein we present preliminary results on the deposition of hydrous magnesium silicates on self-assembled monolayers (-OH, -COOH, -CH3, and -H2PO3 terminated surfaces) at ambient conditions.

  12. Silicates on Iapetus from Cassini's Composite Infrared Spectrometer

    CERN Document Server

    Young, Cindy L; Clark, Roger N; Spencer, John R; Jennings, Donald E; Hand, Kevin P; Poston, Michael J; Carlson, Robert W

    2015-01-01

    We present the first spectral features obtained from Cassini's Composite Infrared Spectrometer (CIRS) for any icy moon. The spectral region covered by CIRS focal planes (FP) 3 and 4 is rich in emissivity features, but previous studies at these wavelengths have been limited by low signal to noise ratios (S/Rs) for individual spectra. Our approach is to average CIRS FP3 spectra to increase the S/R and use emissivity spectra to constrain the composition of the dark material on Iapetus. We find an emissivity feature at ~855 cm-1 and a possible doublet at 660 and 690 cm-1 that do not correspond to any known instrument artifacts. We attribute the 855 cm-1 feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths. Silicates on the dark terrains of Saturn's icy moons have been suspected for decades, but there have been no definitive detections until now. Serpentines reported in the literature at ambient temperature and pressure hav...

  13. Cobalt silicate hierarchical hollow spheres for lithium-ion batteries

    Science.gov (United States)

    Yang, Jun; Guo, Yuanyuan; Zhang, Yufei; Sun, Chencheng; Yan, Qingyu; Dong, Xiaochen

    2016-09-01

    In this paper, the synthesis of cobalt silicate novel hierarchical hollow spheres via a facile hydrothermal method is presented. With a unique hollow structure, the Co2SiO4 provides a large surface area, which can shorten the lithium ions diffusion length and effectively accommodate the volumetic variation during the lithiation/de-lithiation process. Serving as an anode material in lithium-ion battery application, the Co2SiO4 electrode demonstrates a high reversible specific capacity (first-cycle charge capacity of 948.6 mAh g-1 at 100 mA g-1), a cycling durability (specific capacity of 791.4 mAh g-1 after 100 cycles at 100 mA g-1), and a good rate capability (specific capacity of 349.4 mAh g-1 at 10 A g-1). The results indicate that the cobalt silicate hierarchical hollow sphere holds the potential applications in energy storage electrodes.

  14. Polymer-Layered Silicate Nanocomposites for Cryotank Applications

    Science.gov (United States)

    Miller, Sandi G.; Meador, Michael A.

    2007-01-01

    Previous composite cryotank designs have relied on the use of conventional composite materials to reduce microcracking and permeability. However, revolutionary advances in nanotechnology derived materials may enable the production of ultra-lightweight cryotanks with significantly enhanced durability and damage tolerance, as well as reduced propellant permeability. Layered silicate nanocomposites are especially attractive in cryogenic storage tanks based on results that have been reported for epoxy nanocomposite systems. These materials often exhibit an order of magnitude reduction in gas permeability when compared to the base resin. In addition, polymer-silicate nanocomposites have been shown to yield improved dimensional stability, strength, and toughness. The enhancement in material performance of these systems occurs without property trade-offs which are often observed in conventionally filled polymer composites. Research efforts at NASA Glenn Research Center have led to the development of epoxy-clay nanocomposites with 70% lower hydrogen permeability than the base epoxy resin. Filament wound carbon fiber reinforced tanks made with this nanocomposite had a five-fold lower helium leak rate than the corresponding tanks made without clay. The pronounced reduction observed with the tank may be due to flow induced alignment of the clay layers during processing. Additionally, the nanocomposites showed CTE reductions of up to 30%, as well as a 100% increase in toughness.

  15. Evidence of yttrium silicate inclusions in YSZ-porcelain veneers.

    Science.gov (United States)

    Stoner, Brian R; Griggs, Jason A; Neidigh, John; Piascik, Jeffrey R

    2014-04-01

    This report introduces the discovery of crystalline defects that can form in the porcelain veneering layer when in contact with yttria-stabilized zirconia (YSZ). The focus was on dental prostheses and understanding the defects that form in the YSZ/porcelain system; however the data reported herein may have broader implications toward the use and stability of YSZ-based ceramics in general. Specimens were cut from fully sintered YSZ plates and veneering porcelain was applied (porcelain veneer. Local EDAX (SEM) was performed in the regions of visible inclusions and showed significant increases in yttrium concentration. TEM specimens also showed apparent inclusions in the porcelain and selected area electron diffraction was performed on these regions and found the inclusions to be crystalline and identified as either yttrium-silicate (Y2 SiO5 ) or yttrium-disilicate (Y2 Si2 O7 ). Micro-CT data showed that yttrium-silicate precipitates were distributed throughout the thickness of the porcelain veneer. Future studies are needed to determine whether many of the premature failures associated with this materials system may be the result of crystalline flaws that form as a result of high temperature yttrium diffusion near the surfaces of YSZ.

  16. A silicate disk in the heart of the Ant

    CERN Document Server

    Chesneau, Olivier; Balick, Bruce; Lagadec, Eric; Matsuura, Mikako; Smith, Nathan; Spang, Alain; Wolf, Sebastian; Zijlstra, Albert A

    2007-01-01

    We aim at getting high spatial resolution information on the dusty core of bipolar planetary nebulae to directly constrain the shaping process. Methods: We present observations of the dusty core of the extreme bipolar planetary nebula Menzel 3 (Mz 3, Hen 2-154, the Ant) taken with the mid-infrared interferometer MIDI/VLTI and the adaptive optics NACO/VLT. The core of Mz 3 is clearly resolved with MIDI in the interferometric mode, whereas it is unresolved from the Ks to the N bands with single dish 8.2 m observations on a scale ranging from 60 to 250 mas. A striking dependence of the dust core size with the PA angle of the baselines is observed, that is highly suggestive of an edge-on disk whose major axis is perpendicular to the axis of the bipolar lobes. The MIDI spectrum and the visibilities of Mz 3 exhibit a clear signature of amorphous silicate, in contrast to the signatures of crystalline silicates detected in binary post-AGB systems, suggesting that the disk might be relatively young. We used radiative-...

  17. The structure of alkali silicate gel by total scattering methods

    KAUST Repository

    Benmore, C.J.

    2010-06-01

    The structure of the alkali silicate gel (ASR) collected from the galleries of Furnas Dam in Brazil was determined by a pair distribution function (PDF) analysis of high energy X-ray diffraction data. Since this method is relatively new to concrete structure analysis a detailed introduction on the PDF method is given for glassy SiO2. The bulk amorphous structure of the dam material is confirmed as no Bragg peaks are observed in the scattered intensity. The real space results show that the local structure of the amorphous material is similar to kanemite (KHSi2O5:3H2O) however the long range layer structure of the crystal is broken up in the amorphous state, so that ordering only persists of the length scale of a few polyhedra. The silicate layer structure is a much more disordered than predicted by molecular dynamics models. The X-ray results are consistent with the molecular dynamics model of Kirkpatrick et al. (2005) [1] which predicts that most of the water resides in pores within the amorphous network rather than in layers. The total scattering data provide a rigorous basis against which other models may also be tested. © 2010.

  18. Santaclaraite, a new calcium-manganese silicate hydrate from California.

    Science.gov (United States)

    Erd, Richard C.; Ohashi, Y.

    1984-01-01

    Santaclaraite, ideally CaMn4(Si5O14(OH))(OH).H2O, occurs as pink and tan veins and masses in Franciscan chert in the Diablo Range, Santa Clara and Stanislaus counties, California. It is associated with four unidentified Mn silicates, Mn-howieite, quartz, braunite, calcite, rhodochrosite, kutnahorite, baryte, harmotome, chalcopyrite and native copper. Santaclaraite is triclinic, space group B1, a 15.633(1), b 7.603(1) , c 12.003(1) A, alpha 109.71(1)o, beta 88.61(1)o, gamma 99.95(1) o, V 1322.0(3) A3; Z = 4. The strongest lines of the X-ray pattern are 7.04(100), 3.003(84), 3.152(80), 7.69(63), 3.847(57) A. Crystals are lamellar to prismatic (flattened on (100)), with good cleavage on (100) and (010); H. 61/2 Dcalc. 3.398 g/cm3, Dmeas. 3.31 (+ or -0.01); optically biaxial negative, alpha 1.681, beta 1.696, gamma 1.708 (all + or - 0.002), 2Valpha 83 (+ or -1)o. Although chemically a hydrated rhodonite, santaclaraite dehydrates to Mn-bustamite at approx 550oC (in air) . Santaclaraite is a five-tetrahedral-repeat single-chain silicate and has structural affinities with rhodonite, nambulite, marsturite, babingtonite and inesite.-J.A.Z.

  19. Relaxation phenomena in rubber/layered silicate nanocomposites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available Broadband Dielectric Spectroscopy (BDS is employed in order to investigate relaxation phenomena occurring in natural rubber (NR, polyurethane rubber (PUR and PUR/NR blend based nanocomposites, reinforced by 10 parts per hundred (phr Layered Silicates (LS. Nanocomposites and matrices were examined under identical conditions in a wide frequency (10–1 to 106 Hz and temperature (–100 to 50°C range. Experimental data are analyzed in terms of electric modulus formalism. The recorded relaxation phenomena include contributions from both the polymer matrices and the nanofiller. Natural rubber is a non-polar material and its performance is only slightly affected by the presence of layered silicates. Polyurethane rubber exhibits four distinct relaxation processes attributed, with ascending relaxation rate, to Interfacial Polarization (IP, glass/rubber transition (α-mode, local motions of polar side groups and small segments of the polymer chain (β, γ-mode. The same processes have been detected in all systems containing PUR. IP is present in all nanocomposites being the slowest recorded process. Finally, pronounced interfacial relaxation phenomena, occurring in the PUR+10 phr LS spectra, are attributed to nanoscale effects of intercalation and exfoliation.

  20. Flared Disks and Silicate Emission in Young Brown Dwarfs

    CERN Document Server

    Mohanty, S; Natta, A; Fujiyoshi, T; Tamura, M; Barrado y Navascués, D; Mohanty, Subhanjoy; Jayawardhana, Ray; Natta, Antonella; Fujiyoshi, Takuya; Tamura, Motohide; Navascues, David Barrado y

    2004-01-01

    We present mid-infrared photometry of three very young brown dwarfs located in the $\\rho$ Ophiuchi star-forming region -- GY5, GY11 and GY310 --obtained with the Subaru 8-meter telescope. All three sources were detected at 8.6 and 11.7$\\mu$m, confirming the presence of significant mid-infrared excess arising from optically thick dusty disks. The spectral energy distributions of both GY310 and GY11 exhibit strong evidence of flared disks; flat disks can be ruled out for these two brown dwarfs. The data for GY5 show large scatter, and are marginally consistent with both flared and flat configurations. Inner holes a few substellar radii in size are indicated in all three cases (and especially in GY11), in agreement with magnetospheric accretion models. Finally, our 9.7$\\mu$m flux for GY310 implies silicate emission from small grains on the disk surface (though the data do not completely preclude larger grains with no silicate feature). Our results demonstrate that disks around young substellar objects are analog...

  1. Oxidation kinetics of aluminum diboride

    Energy Technology Data Exchange (ETDEWEB)

    Whittaker, Michael L., E-mail: michaelwhittaker2016@u.northwestern.edu [Department of Materials Science and Engineering, University of Utah, 122S. Central Campus Drive, Salt Lake City, UT 84112 (United States); Sohn, H.Y. [Department of Metallurgical Engineering, University of Utah, 135S 1460 E, Rm 00412, Salt Lake City, UT 84112 (United States); Cutler, Raymond A. [Ceramatec, Inc., 2425S. 900W., Salt Lake City, UT 84119 (United States)

    2013-11-15

    The oxidation characteristics of aluminum diboride (AlB{sub 2}) and a physical mixture of its constituent elements (Al+2B) were studied in dry air and pure oxygen using thermal gravimetric analysis to obtain non-mechanistic kinetic parameters. Heating in air at a constant linear heating rate of 10 °C/min showed a marked difference between Al+2B and AlB{sub 2} in the onset of oxidation and final conversion fraction, with AlB{sub 2} beginning to oxidize at higher temperatures but reaching nearly complete conversion by 1500 °C. Kinetic parameters were obtained in both air and oxygen using a model-free isothermal method at temperatures between 500 and 1000 °C. Activation energies were found to decrease, in general, with increasing conversion for AlB{sub 2} and Al+2B in both air and oxygen. AlB{sub 2} exhibited O{sub 2}-pressure-independent oxidation behavior at low conversions, while the activation energies of Al+2B were higher in O{sub 2} than in air. Differences in the composition and morphology between oxidized Al+2B and AlB{sub 2} suggested that Al{sub 2}O{sub 3}–B{sub 2}O{sub 3} interactions slowed Al+2B oxidation by converting Al{sub 2}O{sub 3} on aluminum particles into a Al{sub 4}B{sub 2}O{sub 9} shell, while the same Al{sub 4}B{sub 2}O{sub 9} developed a needle-like morphology in AlB{sub 2} that reduced oxygen diffusion distances and increased conversion. The model-free kinetic analysis was critical for interpreting the complex, multistep oxidation behavior for which a single mechanism could not be assigned. At low temperatures, moisture increased the oxidation rate of Al+2B and AlB{sub 2}, but both appear to be resistant to oxidation in cool, dry environments. - Graphical abstract: Isothermal kinetic data for AlB{sub 2} in air, showing a constantly decreasing activation energy with increasing conversion. Model-free analysis allowed for the calculation of global kinetic parameters despite many simultaneous mechanisms occurring concurrently. (a) Time

  2. Wastewater sludge dewaterability enhancement using hydroxyl aluminum conditioning: Role of aluminum speciation.

    Science.gov (United States)

    Cao, Bingdi; Zhang, Weijun; Wang, Qiandi; Huang, Yangrui; Meng, Chenrui; Wang, Dongsheng

    2016-11-15

    Chemical conditioning is one of the most important processes for improve the performance of sludge dewatering device. Aluminum salt coagulant has been widely used in wastewater and sludge treatment. It is generally accepted that pre-formed speciation of aluminum salt coagulants (ASC) has an important influence on coagulation/flocculation performance. In this study, the interaction mechanisms between sludge particles and aluminum salt coagulants with different speciation of hydroxy aluminum were investigated by characterizing the changes in morphological and EPS properties. It was found that middle polymer state aluminum (Alb) and high polymer state aluminum (Alc) performed better than monomer aluminum and oligomeric state aluminum (Ala) in reduction of specific resistance to filtration (SRF) and compressibility of wastewater sludge due to their higher charge neutralization and formed more compact flocs. Sludge was significantly acidified after addition Ala, while pH was much more stable under Alb and Alc conditioning due to their hydrolysis stability. The size of sludge flocs conditioned with Alb and Alc was small but flocs structure was denser and more compact, and floc strength is higher, while that formed from Ala is relatively large, but floc structure was loose, floc strength is relatively lower. Scanning environmental microscope analysis revealed that sludge flocs conditioned by Alb and Alc (especially PAC2.5 and Al13) exhibited obvious botryoidal structure, this is because sludge flocs formed by Alb and Alc were more compact and floc strength is high, it was easy generated plentiful tiny channels for water release. In addition, polymeric aluminum salt coagulant (Alb, Alc) had better performance in compressing extracellular polymeric substances (EPS) structure and removing sticky protein-like substances from soluble EPS fraction, contributing to improvement of sludge filtration performance. Therefore, this study provides a novel solution for improving sludge

  3. Kinetics of aluminum lithium alloys

    Science.gov (United States)

    Pletcher, Ben A.

    2009-12-01

    Aluminum lithium alloys are increasingly used in aerospace for their high strength-to-weight ratio. Additions of lithium, up to 4.2 wt% decrease the alloy density while increasing the modulus and yield strength. The metastable, second phase Al3Li or delta' is intriguing, as it remains spherical and coherent with the matrix phase, alpha, well into the overaged condition. Small interfacial strain energy allows these precipitates to remain spherical for volume fractions (VV ) of delta' less than 0.3, making this alloy system ideal for investigation of late-stage coarsening phenomena. Experimental characterization of three binary Al-Li alloys are presented as a critical test of diffusion screening theory and multi-particle diffusion simulations. Quantitative transmission electron microscopy is used to image the precipitates directly using the centered dark-field technique. Images are analyzed autonomously within a novel Matlab function that determines the center and size of each precipitate. Particle size distribution, particle growth kinetics, and maximum particle size are used to track the precipitate growth and correlate with the predictions of screening theory and multi-particle diffusion simulations. This project is the first extensive study of Al-Li alloys, in over 25 years, applying modern transmission electron microscopy and image analysis techniques. Previous studies sampled but a single alloy composition, and measured far fewer precipitates. This study investigates 3 alloys with volume fractions of the delta precipitates, VV =0.1-0.27, aged at 225C for 1 to 10 days. More than 1000 precipitates were sampled per aging time, creating more statistically significant data. Experimental results are used to test the predictions based on diffusion screening theory and multi-particle aging simulations. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

  4. Interaction of dispersed polyvynil acetate with silicate in finishing materials

    Directory of Open Access Journals (Sweden)

    Runova, R. F.

    1996-12-01

    Full Text Available This article focuses on the processes of interaction between calcium silicate hydrates and dispersed polyvinyl acetate in tight films with the aim of developing compounds meant for restoration and finishing works. The basis of this development relies on the concept concerning the determining role of the crystal-chemical factor of the silicate phase in the formation of organic-mineral compounds of increased durability. The characteristics of dispersed calcium silicate hydrates are portrayed. The preparation conditions, accounting for the synthesis of the product of submicrocrystalline structure, conforming with the stoichiometry CaO∙SiO2 =0.8-2.0 have been determined. The interaction has been studied for compounds achieved by mixing ingredients in a rapid whirling mixer, and subjected to hardening at T=20+2 T. With the aid of XRD, DTA and Infra-Red Spectrometry methods the formation process of the sophisticated polymer silicate phase in the material was observed for a period of 90 days. The properties of the film were investigated and its high resistance against the influence of external factors was established. On this basis a conclusion concerning the quite high effectiveness of substituting portland cement with dispersed calcium silicate hydrate in polymer cement compounds has been made. White colour and other various special properties determine the suitability for repair and finishing works on facades of buildings.

    Este artículo está orientado a estudiar los procesos de interacción entre los silicatos cálcicos hidratados y el acetato de polivinilo disperso en capas impermeables, con el objeto de desarrollar compuestos destinados para la restauración. El fundamento de estos estudios es determinar el papel que los factores cristaloquímicos de las fases silicato tienen en la formación de compuestos órganominerales de elevada durabilidad. Se han descrito las características de los silicatos cálcicos hidratados

  5. Formation and properties of stabilized aluminum nanoparticles.

    Science.gov (United States)

    Meziani, Mohammed J; Bunker, Christopher E; Lu, Fushen; Li, Heting; Wang, Wei; Guliants, Elena A; Quinn, Robert A; Sun, Ya-Ping

    2009-03-01

    The wet-chemical synthesis of aluminum nanoparticles was investigated systematically by using dimethylethylamine alane and 1-methylpyrrolidine alane as precursors and molecules with one or a pair of carboxylic acid groups as surface passivation agents. Dimethylethylamine alane was more reactive, capable of yielding well-defined and dispersed aluminum nanoparticles. 1-Methylpyrrolidine alane was less reactive and more complex in the catalytic decomposition reaction, for which various experimental parameters and conditions were used and evaluated. The results suggested that the passivation agent played dual roles of trapping aluminum particles to keep them nanoscale during the alane decomposition and protecting the aluminum nanoparticles postproduction from surface oxidation and that an appropriate balance between the rate of alane decomposition (depending more sensitively on the reaction temperature) and the timing in the introduction of the passivation agent into the reaction mixture was critical to the desired product mixes and/or morphologies. Some fundamental and technical issues on the alane decomposition and the protection of the resulting aluminum nanoparticles are discussed.

  6. Evaluation of Aluminum in Iranian Consumed Tea

    Directory of Open Access Journals (Sweden)

    Alireza Asgari

    2008-01-01

    Full Text Available Introduction: Black tea leaf is one of the most important sources of Aluminum in dietary. Therefore this research was conducted to assess the amount of Aluminum in Iranian tea infusion. Methods: To assess Aluminum in Iranian consumed tea, 27 tea samples were analyzed for Al concentration for 10 and 60 min infusion, aluminum concentration was measured with atomic absorption and the results were analyzed by SPSS.13 version. Results: The results showed that minimum and maximum concentration of Al in tea infusion for 10 min infusion was 1.59 and 18.60 mg.L-1 respectively in this regard Baroti and Bamdad tea show the highest and lowest concentration respectively in term of Al, Also Statistical analysis with pair T-test showed that infusion time doesn,t significantly effects on aluminum leaching into infusion (P>0.05. Calculation of percentage "available" Al to the human system showed that 1 L of tea can provide 17.68 % of the daily dietary intake of Al, the percentage "available" for absorption in the intestine is only 8.49 % for overall mean Al concentration. Conclusion: Therefore based on our results, tea consumption in medium values cannot cause toxic effects on human. Although it is necessary to note that tea consumption might be toxic because of effects on people with absorption or secretion problems

  7. A study of redox kinetic in silicate melt; Etude cinetique des reactions d'oxydoreduction dans les silicates

    Energy Technology Data Exchange (ETDEWEB)

    Magnien, V

    2005-12-15

    The aim of this thesis is to understand better iron redox reactions and mechanisms in silicate glasses and melts. Particular interest has been paid to the influence of temperature and chemical composition. For this purpose, the influence of alkali element content, iron content and network formers on the kinetics of redox reactions has been determined through XANES and Raman spectroscopy experiments performed either near the glass transition or above the liquidus temperature. As a complement, electrical conductivity and RBS spectroscopy experiments have been made to characterize the diffusivity of the species that transport electrical charges and the reaction morphology, respectively. Temperature and composition variations can induce changes in the dominating redox mechanism. At a given temperature, the parameters that exert the strongest influence on redox mechanisms are the presence or lack of divalent cations and the existing decoupling between the mobility of network former and modifier elements. Near Tg, the diffusion of divalent cations, when present in the melt, controls the kinetics of iron redox reactions along with a flux of electron holes. Composition, through the degree of polymerization and the silicate network structure, influences the kinetics and the nature of the involved cations, but not the mechanisms of the reaction. Without alkaline earth elements, the kinetics of redox reactions are controlled by the diffusion of oxygen species. With increasing temperatures, the diffusivities of all ionic species tend to become similar. The decoupling between ionic fluxes then is reduced so that several mechanisms become kinetically equivalent and can thus coexist. (author)

  8. Influence of silicate on the transport of bacteria in quartz sand and iron mineral-coated sand.

    Science.gov (United States)

    Dong, Zhe; Yang, Haiyan; Wu, Dan; Ni, Jinren; Kim, Hyunjung; Tong, Meiping

    2014-11-01

    The influence of silicate on the transport and deposition of bacteria (Escherichia coli) in packed porous media were examined at a constant 20 mM ionic strength with different silicate concentrations (from 0 to 1 mM) at pH 7. Transport experiments were performed in two types of representative porous media, both bare quartz sand and iron mineral-coated quartz sand. In bare quartz sand, the breakthrough plateaus in the presence of silicate in suspensions were lower and the corresponding retained profiles were higher than those without silicate ions, indicating that the presence of silicate in suspensions decreased cell transport in bare quartz sand. Moreover, the decrease of bacteria transport in quartz sand induced by silicate was more pronounced with increasing silicate concentrations from 0 to 1 mM. However, when EPS was removed from cell surfaces, the presence of silicate in cell suspensions (with different concentrations) did not affect the transport behavior of bacteria in quartz sand. The interaction of silicate with EPS on cell surfaces negatively decreased the zeta potentials of bacteria, resulting in the decreased cell transport in bare quartz sand when silicate was copresent in bacteria suspensions. In contrast, the presence of silicate in suspensions increased cell transport in iron mineral-coated sand. Silicate ions competed with bacteria for the adsorption sites on mineral-coated sand, contributing to the increased cell transport in mineral-coated sand with silicate present in cell suspensions.

  9. EXAMINATION OF SILICATE LIMITATION OF PRIMARY PRODUCTION IN JIAOZHOU BAY, CHINA Ⅰ. SILICATE BEING A LIMITING FACTOR OF PHYTOPLANKTON PRIMARY PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    杨东方; 张经; 吕吉斌; 高振会; 陈豫

    2002-01-01

    Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou B ay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO-3-N, NO-2-N, NH+4-N, SiO2-3-Si, PO3-4-P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq.(1) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temp erature; that the main factor controlling the primary production is Si; that water temper ature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecologica l niches for C, the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D, the coefficient of water temperature's effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay , the biogeochemical sediment process of the silicon, the phytoplankton predominan t species and the phytoplankton structure. The authors considered silicate a limit ing factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and up take by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrins ic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant

  10. EXAMINATION OF SILICATE LIMITATION OF PRIMARY PRODUCTION IN JIAOZHOU BAY, CHINA——I. SILICATE BEING A LIMITING FACTOR OF PHYTOPLANKTON PRIMARY PRODUCTION

    Institute of Scientific and Technical Information of China (English)

    杨东方; 张经; 吕吉斌; 高振会; 陈豫

    2002-01-01

    Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO3--N, NO2--N, NH4+-N, SIO32--Si, PO43--P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq. ( 1 ) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C, the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D, the coefficient of water temperature's effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant

  11. Mechanical and thermal properties of sodium silicate treated moso bamboo particles reinforced PVC composites

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The main objective of this research was to study the potential of sodium silicate modification on moso bamboo particles as reinforcements for thermoplastic. Moso bamboo particles were modified with sodium silicate aqueous solutions (of 0.5%, 1%, 2%, 5% and 10% concentrations). The mechanical properties of sodium silicate treated moso bamboo particles reinforced PVC composites (BPPC) were calculated and compared with raw bamboo particles filled samples. The thermal characteristics of the BPPC were studied to investigate the feasibility of sodium silicate treatment on moso bamboo particles. The particle morphology and BPPC microstructure were investigated by scanning electron microscopy. Results showed that the tensile strength and modulus of elasticity of the BPPC increased before the concentration of sodium silicate solution reached 5% and got their maximum values of 15.72 MPa and 2956.80 MPa, respectively at 5% concentration. The modulus of rupture obtained the maximum value of 27.73 MPa at 2% concentration. The mechanical curve decreased as the concentration of solution went higher. Differential scanning calorimetric analysis illustrated that the sodium silicate solution treated BPPC possesses a better compatibility. More uniform dispersion of moso bamboo particles in PVC matrix was obtained after the sodium silicate treatment. Hence, the sodium silicate was a feasible and competitive agent of creating moso bamboo particles reinforced PVC composites.

  12. Nanoparticles Containing High Loads of Paclitaxel-Silicate Prodrugs: Formulation, Drug Release, and Anticancer Efficacy.

    Science.gov (United States)

    Han, Jing; Michel, Andrew R; Lee, Han Seung; Kalscheuer, Stephen; Wohl, Adam; Hoye, Thomas R; McCormick, Alon V; Panyam, Jayanth; Macosko, Christopher W

    2015-12-07

    We have investigated particle size, interior structure, drug release kinetics, and anticancer efficacy of PEG-b-PLGA-based nanoparticles loaded with a series of paclitaxel (PTX)-silicate prodrugs [PTX-Si(OR)3]. Silicate derivatization enabled us to adjust the hydrophobicity and hydrolytic lability of the prodrugs by the choice of the alkyl group (R) in the silicate derivatives. The greater hydrophobicity of these prodrugs allows for the preparation of nanoparticles that are stable in aqueous dispersion even when loaded with up to ca. 75 wt % of the prodrug. The hydrolytic lability of silicates allows for facile conversion of prodrugs back to the parent drug, PTX. A suite of eight PTX-silicate prodrugs was investigated; nanoparticles were made by flash nanoprecipitation (FNP) using a confined impingement jet mixer with a dilution step (CIJ-D). The resulting nanoparticles were 80-150 nm in size with a loading level of 47-74 wt % (wt %) of a PTX-silicate, which corresponds to 36-59 effective wt % of free PTX. Cryogenic transmission electron microscopy images show that particles are typically spherical with a core-shell structure. Prodrug/drug release profiles were measured. Release tended to be slower for prodrugs having greater hydrophobicity and slower hydrolysis rate. Nanoparticles loaded with PTX-silicate prodrugs that hydrolyze most rapidly showed in vitro cytotoxicity similar to that of the parent PTX. Nanoparticles loaded with more labile silicates also tended to show greater in vivo efficacy.

  13. Synthesis of magnesium silicate from wheat husk ash: Effects of parameters on structural and surface properties

    Directory of Open Access Journals (Sweden)

    Pinar Terzioglu

    2012-11-01

    Full Text Available In the present study, magnesium silicate was produced by using wheat husk ash. Wheat husk was burned at 600 °C to obtain an amorphous ash structure, and the ash was processed with sodium hydroxide solution with heat to extract silica. Sodium silicate solution and magnesium salts were used to synthesize magnesium silicate. The present study investigates effects of the feeding rate on magnesium silicate production (0.6 mL/min, 35 mL/min, 70 mL/min, the type of magnesium salt (MgSO4 • 7H2O or MgCl2 • 6H2O, temperature (25 °C or 50 °C, and the washing agent (water and acetone on the chemical composition and surface characteristics of magnesium silicate. The results demonstrated that all of the variables affected the surface characteristics of magnesium silicate, such as surface area, particle size, and pore volume. However, it was also observed that the studied parameters did not affect the chemical composition of magnesium silicate. The wheat husk ash-based magnesium silicates obtained in the experimental study had a BET surface area ranging from 79 to 91 m2/g and a particle size varying from 42 to 63 µm.

  14. Optical Properties of Astronomical Silicates with Infrared Techniques (OPASI-T)

    Science.gov (United States)

    Rinehart, Stephen

    2010-01-01

    Astronomical dust is observed in a variety of astrophysical environments and plays an important role in radiative processes and chemical evolution in the galaxy. Depending upon the environment, dust can be either carbon-rich or oxygen-rich (silicate grains). Both astronomical observations and ground-based data show that the optical properties of silicates can change dramatically with the crystallinity of the material, and recent laboratory research provides evidence that the optical properties of silicate dust vary as a function of temperature as well. Therefore, correct interpretation of a vast array of astronomical data relies on the understanding of the properties of silicate dust as functions of wavelength, temperature, and crystallinity. The OPASI-T (Optical Properties of Astronomical Silicates with Infrared Techniques) project addresses the need for high quality optical characterization of metal-enriched silicate condensates using a variety of techniques. A combination of both new and established experiments are used to measure the extinction, reflection, and emission properties of amorphous silicates across the infrared (near infrared to millimeter wavelengths), providing a comprehensive data set characterizing the optical parameters of dust samples. We present room temperature measurements and the experimental apparatus to be used to investigate and characterize additional metal-silicate materials.

  15. Synthesis and reaction behavior of calcium silicate hydrate in basic system

    Institute of Scientific and Technical Information of China (English)

    刘桂华; 贺强; 李小斌; 彭志宏; 周秋生

    2004-01-01

    At the molar ratio of CaO to SiO2 of 1, with calcium hydroxide and sodium silicate, calcium silicate hydrate was synthesized at 50, 100, 170 ℃, respectively. The results show that temperature favors the formation of calcium silicate hydrate with perfect structure. When calcium silicate hydrate reacts with caustic solution, the decomposition rate of calcium silicate hydrate increases with the increasing caustic concentration and decreases with the raising synthesis temperature and the prolongation of reaction time. The decomposition rate is all less than 1.2 % in caustic solution, and XRD pattern of the residue after reaction with caustic solution is found as the same as that of original calcium silicate hydrate, which indicates the stable existence of calcium silicate hydrate in caustic solution.When reacted with soda solution, the decomposition rate increases with the increasing soda concentration and reaction time, while decreases with the synthesis temperature. The decomposition rate is more than 2% because CaO · SiO2 · H2O(CSH( Ⅰ )), except Ca5 (OH)2Si6O16 · 4H2O and Ca6Si6O17 (OH)2, is decomposed. So the synthesis temperature and soda concentration should be controlled in the process of transformation of sodium aluminosilicate hydrate into calcium silicate hydrate.

  16. Effect of silicate pretreatment, post-sealing and additives on corrosion resistance of phosphated galvanized steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Sodium silicate (water glass) pretreatment before phosphating, silicate post-sealing after phosphating and adding silicate to a traditional phosphating solution were respectively carried out to obtain the improved phosphate coatings with high corrosion resistance and coverage on hot-dip galvanized(HDG) steel. The corrosion resistance, morphology and chemical composition of the coatings were investigated using neutral salt spray(NSS) tests, scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). The results show that pretreatment HDG steel with silicate solutions, phosphate coatings with finer crystals and higher coverage are formed and the corrosion resistance is enhanced. Adding silicate to a traditional phosphating solution, the surface morphology of the coatings is nearly unchanged. The corrosion resistance of the coatings is mainly dependent on phosphating time.Phosphating for a longer time (such as 5 min), the corrosion resistance, increasing with concentration of silicate, is improved significantly. Post-sealing the phosphated HDG steel with silicate solutions, the pores among the zinc phosphate crystals are sealed with the films containing Si, P, O and Zn and the continuous composite coatings are formed. The corrosion resistance of the composite coatings, related to the pH value, contents of hydrated gel of silica and Si2O52- and post-sealing time, is increased markedly. The improved coatings with optimal corrosion resistance are obtained for phosphating 5 min and post-sealing with 5 g/L silicate solution for 10 min.

  17. A hidden reservoir of Fe/FeS in interstellar silicates?

    CERN Document Server

    Köhler, M; Ysard, N

    2014-01-01

    The depletion of iron and sulphur into dust in the interstellar medium and the exact nature of interstellar amorphous silicate grains is still an open question. We study the incorporation of iron and sulphur into amorphous silicates of olivine- and pyroxene-type and their effects on the dust spectroscopy and thermal emission. We used the Maxwell-Garnett effective-medium theory to construct the optical constants for a mixture of silicates, metallic iron, and iron sulphide. We also studied the effects of iron and iron sulphide in aggregate grains. Iron sulphide inclusions within amorphous silicates that contain iron metal inclusions shows no strong differences in the optical properties of the grains. A mix of amorphous olivine- and pyroxene-type silicate broadens the silicate features. An amorphous carbon mantle with a thickness of 10 nm on the silicate grains leads to an increase in absorption on the short-wavelength side of the 10 $\\mu$m silicate band. The assumption of amorphous olivine-type and pyroxene-typ...

  18. Microstructure engineering of Portland cement pastes and mortars through addition of ultrafine layer silicates

    DEFF Research Database (Denmark)

    Lindgreen, Holger; Geiker, Mette; Krøyer, Hanne;

    2008-01-01

    Pozzolanic submicron-sized silica fume and the non-pozzolanic micron- and nano-sized layer silicates (clay minerals) kaolinite, smectite and palygorskite have been used as additives in Portland cement pastes and mortars. These layer silicates have different particle shape (needles and plates), su...

  19. Molecular Dynamics Modeling of Hydrated Calcium-Silicate-Hydrate (CSH) Cement Molecular Structure

    Science.gov (United States)

    2014-08-30

    properties of key hydrated cement constituent calcium-silicate-hydrate (CSH) at the molecular, nanometer scale level. Due to complexity, still unknown...public release; distribution is unlimited. Molecular Dynamics Modeling of Hydrated Calcium-Silicate- Hydrate (CSH) Cement Molecular Structure The views... Cement Molecular Structure Report Title Multi-scale modeling of complex material systems requires starting from fundamental building blocks to

  20. Facile synthesis of magnetic hierarchical copper silicate hollow nanotubes for efficient adsorption and removal of hemoglobin.

    Science.gov (United States)

    Zhang, Min; Wang, Baoyu; Zhang, Yanwei; Li, Weizhen; Gan, Wenjun; Xu, Jingli

    2016-01-21

    This study reports the fabrication of magnetic copper silicate hierarchical hollow nanotubes, which are featured by a tailored complex wall structure and high surface area. Moreover, they exhibit excellent performance as an easily recycled adsorbent for protein separation. Particularly, this strategy can be extended as a general method to prepare other magnetic metal silicate hollow nanotubes.

  1. Crystal Structure and Chemical Composition of a Presolar Silicate from the Queen Elizabeth Range 99177 Meteorite

    Science.gov (United States)

    Nguyen, A. N.; Keller, L. P.; Rahman, Z.; Messenger, S.

    2013-01-01

    Mineral characterization of presolar silicate grains, the most abundant stardust phase, has provided valuable information about the formation conditions in circumstellar environments and in super-nova (SN) outflows. Spectroscopic observations of dust around evolved stars suggest a majority of amor-phous, Mg-rich olivine grains, but crystalline silicates, most of which are pyroxene, have also been observed [1]. The chemical compositions of hundreds of presolar silicates have been determined by Auger spectroscopy and reveal high Fe contents and nonstoichiometric compositions intermediate to olivine and pyroxene [2-6]. The unexpectedly high Fe contents can partly be attributed to secondary alteration on the meteorite parent bodies, as some grains have Fe isotopic anomalies from their parent stellar source [7]. Only about 35 presolar silicates have been studied for their mineral structures and chemical compositions by transmission electron microscopy (TEM). These grains display a wide range of compositions and structures, including crystalline forsterite, crystalline pyroxene, nanocrystalline grains, and a majority of amorphous nonstoichiometric grains. Most of these grains were identified in the primitive Acfer 094 meteorite. Presolar silicates from this meteorite show a wide range of Fe-contents, suggestive of secondary processing on the meteorite parent body. The CR chondrite QUE 99177 has not suffered as much alteration [8] and displays the highest presolar silicate abundance to date among carbonaceous chondrites [3, 6]. However, no mineralogical studies of presolar silicates from this meteorite have been performed. Here we examine the mineralogy of a presolar silicate from QUE 99177.

  2. FT-IR and 29 Si-NMR for evaluating aluminium silicate precursors for geopolymers

    NARCIS (Netherlands)

    Valcke, S.L.A.; Pipilikaki, P.; Fischer, H.R.; Verkuijlen, M.H.W.; Eck, E.R.H.

    2014-01-01

    Geopolymers are systems of inorganic binders that can be used for sustainable, cementless concrete and are formed by alkali activation of an aluminium–silicate precursor (often secondary resources like fly ash or slag). The type of aluminium– silicate precursor and its potential variations within on

  3. Sodium Silicate Behavior in Porous Media Applied for In-Depth Profile Modifications

    Directory of Open Access Journals (Sweden)

    Hossein A. Akhlaghi Amiri

    2014-03-01

    Full Text Available This paper addresses alkaline sodium silicate (Na-silicate behavior in porous media. One of the advantages of the Na-silicate system is its water-like injectivity during the placement stage. Mixing Na-silicate with saline water results in metal silicate precipitation as well as immediate gelation. This work demonstrated that low salinity water (LSW, sea water diluted 25 times could be used as a pre-flush in flooding operations. A water override phenomenon was observed during gel formation which is caused by gravity segregation. Dynamic adsorption tests in the sand-packed tubes showed inconsiderable adsorbed silicon density (about 8.5 × 10−10 kg/cm3 for a solution with 33 mg/L silicon content, which is less than the estimated mono-layer adsorption density of 1.4 × 10−8 kg/cm3. Na-silicate enhanced water sweep efficiency after application in a dual-permeability sand-pack system, without leak off into the oil-bearing low permeability (LP zone. Field-scale numerical sensitivity studies in a layered reservoir demonstrated that higher permeability and viscosity contrasts and lower vertical/horizontal permeability ratio result in lower Na-silicate leakoff into the matrix. The length of the mixing zone between reservoir water and the injected Na-silicate solution, which is formed by low salinity pre-flush, acts as a buffer zone.

  4. ALUMINUM AND CHROMIUM LEACHING WORKSHOP WHITEPAPER

    Energy Technology Data Exchange (ETDEWEB)

    McCabe, D; Jeff Pike, J; Bill Wilmarth, B

    2007-04-25

    A workshop was held on January 23-24, 2007 to discuss the status of processes to leach constituents from High Level Waste (HLW) sludges at the Hanford and Savannah River Sites. The objective of the workshop was to examine the needs and requirements for the HLW flowsheet for each site, discuss the status of knowledge of the leaching processes, communicate the research plans, and identify opportunities for synergy to address knowledge gaps. The purpose of leaching of non-radioactive constituents from the sludge waste is to reduce the burden of material that must be vitrified in the HLW melter systems, resulting in reduced HLW glass waste volume, reduced disposal costs, shorter process schedules, and higher facility throughput rates. The leaching process is estimated to reduce the operating life cycle of SRS by seven years and decrease the number of HLW canisters to be disposed in the Repository by 1000 [Gillam et al., 2006]. Comparably at Hanford, the aluminum and chromium leaching processes are estimated to reduce the operating life cycle of the Waste Treatment Plant by 20 years and decrease the number of canisters to the Repository by 15,000-30,000 [Gilbert, 2007]. These leaching processes will save the Department of Energy (DOE) billions of dollars in clean up and disposal costs. The primary constituents targeted for removal by leaching are aluminum and chromium. It is desirable to have some aluminum in glass to improve its durability; however, too much aluminum can increase the sludge viscosity, glass viscosity, and reduce overall process throughput. Chromium leaching is necessary to prevent formation of crystalline compounds in the glass, but is only needed at Hanford because of differences in the sludge waste chemistry at the two sites. Improving glass formulations to increase tolerance of aluminum and chromium is another approach to decrease HLW glass volume. It is likely that an optimum condition can be found by both performing leaching and improving

  5. Aluminum phosphate ceramics for waste storage

    Science.gov (United States)

    Wagh, Arun; Maloney, Martin D

    2014-06-03

    The present disclosure describes solid waste forms and methods of processing waste. In one particular implementation, the invention provides a method of processing waste that may be particularly suitable for processing hazardous waste. In this method, a waste component is combined with an aluminum oxide and an acidic phosphate component in a slurry. A molar ratio of aluminum to phosphorus in the slurry is greater than one. Water in the slurry may be evaporated while mixing the slurry at a temperature of about 140-200.degree. C. The mixed slurry may be allowed to cure into a solid waste form. This solid waste form includes an anhydrous aluminum phosphate with at least a residual portion of the waste component bound therein.

  6. NASA-427: A New Aluminum Alloy

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center researchers have developed a new, stronger aluminum alloy, ideal for cast aluminum products that have powder or paint-baked thermal coatings. With advanced mechanical properties, the NASA-427 alloy shows greater tensile strength and increased ductility, providing substantial improvement in impact toughness. In addition, this alloy improves the thermal coating process by decreasing the time required for heat treatment. With improvements in both strength and processing time, use of the alloy provides reduced materials and production costs, lower product weight, and better product performance. The superior properties of NASA-427 can benefit many industries, including automotive, where it is particularly well-suited for use in aluminum wheels.

  7. Dynamic recrystallization behavior of commercial pure aluminum

    Institute of Scientific and Technical Information of China (English)

    LI Hui-zhong; ZHANG Xin-ming; CHEN Ming-an; LIU Zi-juan

    2006-01-01

    The flow stress feature and microstructure evolvement of a commercial pure aluminum were investigated by compression on Gleeble-1500 dynamic materials test machine. Optical microscopy (OM) and transmission electron microscopy (TEM) were applied to analyze the deformation microstructure of the commercial pure aluminum.The results show that the flow stress tends to be constant after a peak value and the dynamic recovery occurs when the deformation temperatures is 220 ℃ with the strain rate of 0.01 s-1; while the dynamic recrystallization occurs when the deformation temperature is higher than 380 ℃, and the flow stress exhibits a single peak at 460 ℃ with different strain rates from 0.001 s-1 to 1 s-1, and continuous dynamic recrystallization and geometric dynamic recrystallization occur during the hot compression of the commercial pure aluminum.

  8. Lithium-aluminum-magnesium electrode composition

    Science.gov (United States)

    Melendres, Carlos A.; Siegel, Stanley

    1978-01-01

    A negative electrode composition is presented for use in a secondary, high-temperature electrochemical cell. The cell also includes a molten salt electrolyte of alkali metal halides or alkaline earth metal halides and a positive electrode including a chalcogen or a metal chalcogenide as the active electrode material. The negative electrode composition includes up to 50 atom percent lithium as the active electrode constituent and a magnesium-aluminum alloy as a structural matrix. Various binary and ternary intermetallic phases of lithium, magnesium, and aluminum are formed but the electrode composition in both its charged and discharged state remains substantially free of the alpha lithium-aluminum phase and exhibits good structural integrity.

  9. Air-Impregnated Nanoporous Anodic Aluminum Oxide Layers for Enhancing the Corrosion Resistance of Aluminum.

    Science.gov (United States)

    Jeong, Chanyoung; Lee, Junghoon; Sheppard, Keith; Choi, Chang-Hwan

    2015-10-13

    Nanoporous anodic aluminum oxide layers were fabricated on aluminum substrates with systematically varied pore diameters (20-80 nm) and oxide thicknesses (150-500 nm) by controlling the anodizing voltage and time and subsequent pore-widening process conditions. The porous nanostructures were then coated with a thin (only a couple of nanometers thick) Teflon film to make the surface hydrophobic and trap air in the pores. The corrosion resistance of the aluminum substrate was evaluated by a potentiodynamic polarization measurement in 3.5 wt % NaCl solution (saltwater). Results showed that the hydrophobic nanoporous anodic aluminum oxide layer significantly enhanced the corrosion resistance of the aluminum substrate compared to a hydrophilic oxide layer of the same nanostructures, to bare (nonanodized) aluminum with only a natural oxide layer on top, and to the latter coated with a thin Teflon film. The hydrophobic nanoporous anodic aluminum oxide layer with the largest pore diameter and the thickest oxide layer (i.e., the maximized air fraction) resulted in the best corrosion resistance with a corrosion inhibition efficiency of up to 99% for up to 7 days. The results demonstrate that the air impregnating the hydrophobic nanopores can effectively inhibit the penetration of corrosive media into the pores, leading to a significant improvement in corrosion resistance.

  10. The Effect of Anodic Oxide Films on the Nickel-Aluminum Reaction in Aluminum Braze Sheet

    Science.gov (United States)

    Tadgell, Colin A.; Wells, Mary A.; Corbin, Stephen F.; Colley, Leo; Cheadle, Brian; Winkler, Sooky

    2017-03-01

    The influence of an anodic oxide surface film on the nickel-aluminum reaction at the surface of aluminum brazing sheet has been investigated. Samples were anodized in a barrier-type solution and subsequently sputtered with nickel. Differential scanning calorimetry (DSC) and metallography were used as the main investigative techniques. The thickness of the anodic film was found to control the reaction between the aluminum substrate and nickel coating. Solid-state formation of nickel-aluminum intermetallic phases occurred readily when a relatively thin oxide film (13 to 25 nm) was present, whereas intermetallic formation was suppressed in the presence of thicker oxides ( 60 nm). At an intermediate oxide film thickness of 35 nm, the Al3Ni phase formed shortly after the initiation of melting in the aluminum substrate. Analysis of DSC traces showed that formation of nickel-aluminum intermetallic phases changed the melting characteristics of the aluminum substrate, and that the extent of this change can be used as an indirect measure of the amount of nickel incorporated into the intermetallic phases.

  11. Reducing aluminum dust explosion hazards: case study of dust inerting in an aluminum buffing operation.

    Science.gov (United States)

    Myers, Timothy J

    2008-11-15

    Metal powders or dusts can represent significant dust explosion hazards in industry, due to their relatively low ignition energy and high explosivity. The hazard is well known in industries that produce or use aluminum powders, but is sometimes not recognized by facilities that produce aluminum dust as a byproduct of bulk aluminum processing. As demonstrated by the 2003 dust explosion at aluminum wheel manufacturer Hayes Lemmerz, facilities that process bulk metals are at risk due to dust generated during machining and finishing operations [U.S. Chemical Safety and Hazard Investigation Board, Investigation Report, Aluminum Dust Explosion Hayes Lemmerz International, Inc., Huntington, Indiana, Report No. 2004-01-I-IN, September 2005]. Previous studies have shown that aluminum dust explosions are more difficult to suppress with flame retardants or inerting agents than dust explosions fueled by other materials such as coal [A.G. Dastidar, P.R. Amyotte, J. Going, K. Chatrathi, Flammability limits of dust-minimum inerting concentrations, Proc. Saf. Progr., 18-1 (1999) 56-63]. In this paper, an inerting method is discussed to reduce the dust explosion hazard of residue created in an aluminum buffing operation as the residue is generated. This technique reduces the dust explosion hazard throughout the buffing process and within the dust collector systems making the process inherently safer. Dust explosion testing results are presented for process dusts produced during trials with varying amounts of flame retardant additives.

  12. Dynamic Strengthening During High Velocity Shear Experiments with Siliceous Rocks

    Science.gov (United States)

    Liao, Z.; Chang, J. C.; Boneh, Y.; Chen, X.; Reches, Z.

    2011-12-01

    It is generally accepted that dynamic-weakening is essential for earthquake instability, and many experimental works have documented this weakening. Recent observations revealed also opposite trends of dynamic-strengthening in experiments (Reches & Lockner, 2010). We present here our experimental results of this dynamic-strengthening and discuss possible implications to earthquake behavior. We ran hundreds of experiments on experimental faults made of siliceous rock including granite, syenite, diorite, and quartzite. The experimental fault is comprised of two solid cylindrical blocks with a raised-ring contact of 7 cm diameter and 1 cm width. We recognized general, three regimes of strength-velocity relations: (I) Dynamic weakening (drop of 20-60% of static strength) as slip velocity increased from ~0.0003 m/s (lowest experimental velocity) to a critical velocity, Vc=0.008-0.16 m/s; (II) Abrupt transition to dynamic strengthening regime during which the fault strength almost regains its static strength; and (III) Quasi-constant strength with further possible drops as velocity approaches ~1 m/s. The critical velocity depends on the sample lithology: Vc is ~0.06 m/s for granite, ~0.008 m/s for syenite, ~0.01 m/s for diorite, and ~0.16 m/s for quartzite. The strengthening stage is associated with temperature increase, wear-rate increase, and the occurrence of intense, high frequency stick-slip events (Reches & Lockner, 2010). Sammis et al., (this meeting) attributed this strengthening to dehydration of the thin water layer that covers the gouge particles as the temperature increases. On the other hand, we note that tens of experiments with dolomite samples (non-siliceous), which were deformed under similar conditions, did not exhibit the velocity strengthening (unpublished). Based on the analyses by Andrews (2004, 2005), we speculate that velocity strengthening may bound the slip velocity. The numerical models of Andrews show that the slip velocity along a slip

  13. LUMINESCENT PROPERTIES OF SILICATE GLASSES WITH CERIUM IONS AND ANTIMONY

    Directory of Open Access Journals (Sweden)

    A. M. Klykova

    2014-05-01

    Full Text Available The paper deals with the results of an experimental study of luminescence excitation spectra and luminescence of silicate glasses containing cerium ions and antimony. The aim of this work was to study the features of the luminescence and the effect of UV irradiation and heat treatment on luminescence and the state of cerium ions and antimony in glass. We investigated glass system Na2O-ZnO-Al2O3-SiO2-NaF-NaBr with additives CeO2 and Sb2O3. Synthesis was carried out in platinum crucibles in the air at 14500C. The samples were polished glass plates with a thickness of 0.5-1 mm. UV irradiation was carried out with a mercury lamp having a wide range of radiation in the spectral range 240-390 nm. It was conducted in a Nabertherm muffle furnaces. Luminescence spectra and excitation spectra were measured using a spectrofluorimeter MPF-44A (PerkinElmer at the room temperature. Measured luminescence spectra were corrected in view of the spectral sensitivity of the photodetector for spectrofluorimeter. Adjustment of the excitation spectra for the spectral dependence of the intensity of the excitation source was not carried out. During the experiments it was found that in silicate glasses Sb3+ ions can exist in two energy states, which corresponds to a different environment with oxygen ions. Heat treatment of these glasses in an oxidizing atmosphere leads to an increase in ion concentration of Sb3+ ions with a greater amount of oxygen in the environment. In glasses containing antimony and cerium ions, ultraviolet irradiation causes a change in the valence of cerium ions and antimony, which is accompanied by luminescence quenching. Subsequent heat treatment of glass leads to the inverse processes and restore luminescence excitation spectra. The study of fluorescent properties of silicate glasses with cerium and antimony ions led to the conclusion of the practical significance of this work. Promising multifunctional materials can be created on the basis of

  14. Interaction of catechins with aluminum in vitro

    Institute of Scientific and Technical Information of China (English)

    唐德松; 沈生荣; 陈勋; 张玉艳; 许重阳

    2004-01-01

    Tea is one of the most popular beverages, consumed by over two thirds of the world's population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum's known adverse effect on human health. Investigation of the interactions of catechins with A13+ showed that during the interaction of catechins with A13+, the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C's at 278 nm changed little. The ratio of A13+ to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the A1-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of A1-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with A13+ was the same as that of EGCG, with a little difference for EC. When the ratio of A13+ to EC was1. It was found that the ratio of A13+ to EC in the polymer was 1:1. Polymerization of A1-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer,indicating that these compounds may reduce aluminum absorption during tea intake.

  15. Interaction of catechins with aluminum in vitro

    Institute of Scientific and Technical Information of China (English)

    唐德松; 沈生荣; 陈勋; 张玉艳; 许重阳

    2004-01-01

    Tea is one of the most popular beverages, consumed by over two thirds of the world's population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum's known adverse effect on human health. Investigation of the interactions of catechins with Al3+ showed that during the interaction of catechins with Al3+, the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C's at 278 nm changed little. The ratio of Al3+ to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al3+ was the same as that of EGCG, with a little difference for EC. When the ratio of Al3+ to EC was 1. It was found that the ratio of Al3+ to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake.

  16. Effect of Electrolyte on the Dissolution of Aluminum from Acid Sois and the Distribution of Aluminum Forms in Soil Solution

    Institute of Scientific and Technical Information of China (English)

    XURENKOU; JIGUOLIANG

    1997-01-01

    KCl,CaCl2,NH4Cl,NaCl,K2SO4 and KF solutions were used for studying the effects of cations and anions on the dissolution of aluminum and the distribution of aluminum forms respectively.Power of exchanging and releasing aluminum of four kinds of cations was in the decreasing order Ca2+>K+>NH4+>Na+,The dissolution of aluminum increased with the cation concentration.The adsorption affinity of various soils fro aluminum was different.The aluminum in the soil with a stronger adsorption affinity was diffcult to be exchanged and released by cations.The Al-F complexes were main species of inorganic aluminum at a low concentration of cations,while Al3+ became major species of inorganic aluminum at a hiht concentration of cations .The results on the effct of anions indicated that the concentrations of total aluminum,three kinds of inorganc aluminum(Al3+,Al-F and Al-OH complexes) and organic aluminum complexes(Al-OM) when SO42- was added into soil suspension were lower than those when Cl- was added.The dissolution of aluminum from soils and the distribution of aluminum forms in solution were affected by the adsorption of F- on the soil.For soils with strong affinity for F-,the concentrations of the three inorganic aluminum species in soil solution after addition of F- were lower than those after addition of Cl-;but for soils with weak affinity for F-,the concentrations of Al3+ and Al-OM were lower and the concentrations of Al-F complexes and total inorganic aluminum after addition of F- were higher than those after addition of Cl- .The increase of F- concentration in soil solution accelerated the dissolution of aluminum from soils.

  17. Composite purification technology and mechanism of recycled aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    房文斌; 耿耀宏; 安阁英; 叶荣茂

    2002-01-01

    Iron-rich inclusions in aluminum alloys can be effectively removed by composite purification of sedimentation and filtration technology.The results show that the purposed method has no negative effects on aluminum alloys and obviously improve their mechanical properties.

  18. Understanding Aspects of Aluminum Exposure in Alzheimer's Disease Development.

    Science.gov (United States)

    Kandimalla, Ramesh; Vallamkondu, Jayalakshmi; Corgiat, Edwin B; Gill, Kiran Dip

    2016-03-01

    Aluminum is a ubiquitously abundant nonessential element. Aluminum has been associated with neurodegenerative diseases such as Alzheimer's disease (AD), amyotrophic lateral sclerosis, and dialysis encephalopathy. Many continue to regard aluminum as controversial although increasing evidence supports the implications of aluminum in the pathogenesis of AD. Aluminum causes the accumulation of tau protein and Aβ protein in the brain of experimental animals. Aluminum induces neuronal apoptosis in vivo and in vitro, either by endoplasmic stress from the unfolded protein response, by mitochondrial dysfunction, or a combination of them. Some, people who are exposed chronically to aluminum, either from through water and/or food, have not shown any AD pathology, apparently because their gastrointestinal barrier is more effective. This article is written keeping in mind mechanisms of action of aluminum neurotoxicity with respect to AD.

  19. [Aluminum induces chromosome aberrations in wheat root meristem cells].

    Science.gov (United States)

    Bulanova, N V; Synzynys, B I; Koz'min, G V

    2001-12-01

    The yield and pattern of chromosome structure aberrations in wheat seedlings treated with aluminum nitrate and aluminum sulfate at various concentrations have been determined by the anaphase method. Aluminum has a genotoxic effect causing genome, chromatid, and chromosome aberrations in apical root meristem cells. The relationship between the total yield of structural mutations and the aluminum concentration follows a bell-shaped curve. The mutagenic activity of aluminum nitrate peaks at 10(-3) mg/ml, which is twice as high as the permissible concentration limit (PCL) of aluminum in potable water. The maximum of the mutagenic activity of aluminum sulfate is observed at 5 x 10(-4) mg/ml, i.e., one PCL. Tap water boiled for 2 h in an aluminum vessel has virtually no genotoxic effect on wheat cells.

  20. Method of winning aluminum metal from aluminous ore

    Science.gov (United States)

    Loutfy, Raouf O.; Keller, Rudolf; Yao, Neng-Ping

    1981-01-01

    Aluminous ore such as bauxite containing alumina is blended with coke or other suitable form of carbon and reacted with sulfur gas at an elevated temperature. For handling, the ore and coke can be extruded into conveniently sized pellets. The reaction with sulfur gas produces molten aluminum sulfide which is separated from residual solid reactants and impurities. The aluminum sulfide is further increased in temperature to cause its decomposition or sublimation, yielding aluminum subsulfide liquid (AlS) and sulfur gas that is recycled. The aluminum monosulfide is then cooled to below its disproportionation temperature to again form molten aluminum sulfide and aluminum metal. A liquid-liquid or liquid-solid separation, depending on the separation temperature, provides product aluminum and aluminum sulfide for recycle to the disproportionation step.

  1. Anodization process produces opaque, reflective coatings on aluminum

    Science.gov (United States)

    1965-01-01

    Opaque, reflective coatings are produced on aluminum articles by an anodizing process wherein the anodizing bath contains an aqueous dispersion of finely divided insoluble inorganic compounds. These particles appear as uniformly distributed occlusions in the anodic deposit on the aluminum.

  2. Low Mass, Aluminum NOFBX Combustion Chamber Development Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Our team proposes to define a diffusion bonding process for aluminum as an enabling step to ultimately develop an innovative, lightweight, long life, aluminum...

  3. Refined Aluminum Industry Suffers From Deficit and Western Investment Accelerates

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>Under the backdrop of loss of the entire refined aluminum industry,the investment in electrolytic aluminum accelerates.The reporter learnt from a recent survey that,many companies including Shandong Xinfa Group,East Hope

  4. Newly Identified Silicate Carbon Stars from IRAS Low-Resolution Spectra

    Institute of Scientific and Technical Information of China (English)

    Pei-Sheng Chen; Pin Zhang

    2006-01-01

    The discovery of silicate carbon star poses a challenge to the theory of stellar evolution in the late stage, hence it is important to look for more silicate carbon stars. To this end we have carried out cross-identifications between the new IRAS Low-Resolution Spectrum (LRS) database and the new carbon star catalog, CGCS3. We have found nine new silicate carbon stars with silicate features around 10μm and/or 18 μm. These newly identified stars are located in the Regions Ⅲa and Ⅶ in the IRAS two-color diagram, which means they indeed have typical far infrared colors of silicate carbon stars. The infrared properties of each of these sources are discussed.

  5. Bioactivity studies of calcium magnesium silicate prepared from eggshell waste by sol–gel combustion synthesis

    Directory of Open Access Journals (Sweden)

    Rajan Choudhary

    2015-06-01

    Full Text Available The present study focused on the synthesis of calcium magnesium silicate (akermanite, Ca2MgSi2O7 using eggshell biowaste (as calcium source, magnesium nitrate and tetraethyl orthosilicate (TEOS as starting materials. Sol–gel combustion method was adopted to obtain calcium magnesium silicate. Citric acid was used as a fuel (reducing agent and nitrate ions present in the metal nitrates acts as an oxidizing agent during combustion process. The characterization of synthesized calcium magnesium silicate was carried out by powder X-ray diffraction (XRD, Fourier transform infrared (FTIR and scanning electron microscopy (SEM techniques. Calcium magnesium silicate crystallite size was observed in nano regime which can effectively mimic natural bone apatite composition. In-vitro bioactivity was investigated by immersing calcium magnesium silicate pellet in simulated body fluid (SBF for three weeks. Results show effective deposition of crystallized hydroxyapatite (HAP layer on its surface and predicting its possibilities for applications in hard tissue regeneration.

  6. Soft X-ray Irradiation of Silicates: Implications on Dust Evolution in Protoplanetary Disks

    CERN Document Server

    Ciaravella, A; Chen, Y -J; Caro, G M Muñoz; Huang, C -H; Jiménez-Escobar, A; Venezia, A M

    2016-01-01

    The processing of energetic photons on bare silicate grains was simulated experimentally on silicate ?lms submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted solgel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may have relevant implications in the evolution of silicate materials in X-ray irradiated protoplanetary disks.

  7. Identification of an Extremely 180-Rich Presolar Silicate Grain in Acfer 094

    Science.gov (United States)

    Nguyen, A. N.; Messenger, S.

    2009-01-01

    Presolar silicate grains have been abundantly identified since their first discovery less than a decade ago [1,2,3]. The O isotopic compositions of both silicate and oxide stardust indicate the vast majority (>90%) condensed around Orich asymptotic giant branch (AGB) stars. Though both presolar phases have average sizes of 300 nm, grains larger than 1 m are extremely uncommon for presolar silicates. Thus, while numerous isotopic systems have been measured in presolar oxide grains [4], very few isotopic analyses for presolar silicates exist outside of O and Si [2,5]. And still, these measurements suffer from isotopic dilution with surrounding matrix material [6]. We conduct a search for presolar silicates in the primitive carbonaceous chondrite Acfer 094 and in some cases obtain high spatial resolution, high precision isotopic ratios.

  8. Soft X-Ray Irradiation of Silicates: Implications for Dust Evolution in Protoplanetary Disks

    Science.gov (United States)

    Ciaravella, A.; Cecchi-Pestellini, C.; Chen, Y.-J.; Muñoz Caro, G. M.; Huang, C.-H.; Jiménez-Escobar, A.; Venezia, A. M.

    2016-09-01

    The processing of energetic photons on bare silicate grains was simulated experimentally on silicate films submitted to soft X-rays of energies up to 1.25 keV. The silicate material was prepared by means of a microwave assisted sol-gel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry with residual impurities due to the synthesis method. The experiments were performed using the spherical grating monochromator beamline at the National Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray irradiation induces structural changes that can be interpreted as an amorphization of the processed silicate material. The present results may have relevant implications in the evolution of silicate materials in X-ray-irradiated protoplanetary disks.

  9. Iron and aluminum in Alzheimer's disease.

    Science.gov (United States)

    Di Lorenzo, Francesco; Di Lorenzo, Berardino

    2013-01-01

    In this case presentation, a woman with high serum levels of aluminum was treated with chelation therapy with deferoxamine and ascorbic acid. This patient was initially bedridden and the clinical situation was complicated by epileptic seizures. After the chelation therapy, the clinical condition was ameliorated and the therapy continued without the correlation to aluminum serum levels. The role of metals in neurodegenerative disorders and the correlation between iron metabolism and amyloid beta peptide are described. This case suggests chelation therapy could represent a promising therapeutic option for this dramatic disease.

  10. Sound absorption property of openpore aluminum foams

    Directory of Open Access Journals (Sweden)

    WANG Fang

    2007-02-01

    Full Text Available This paper presents a study on sound absorption property of aluminum foam by evaluating its sound absorption coefficients using standing wave tube method. Experimental results showed that the average values of sound absorption coefficients (over the test frequency range are all above 0.4, which indicate very good sound absorption property of the aluminum foams. The sound absorption coefficient is affected by frequency and pore structure, and reaches its maximum value at around 1 000 Hz. With the increase of porosity and decrease of cell diameter, the sound absorption coefficient values increase.

  11. Aluminum plasmonic metamaterials for structural color printing.

    Science.gov (United States)

    Cheng, Fei; Gao, Jie; Stan, Liliana; Rosenmann, Daniel; Czaplewski, David; Yang, Xiaodong

    2015-06-01

    We report a structural color printing platform based on aluminum plasmonic metamaterials supporting near perfect light absorption and narrow-band spectral response tunable across the visible spectrum to realize high-resolution, angle-insensitive color printing with high color purity and saturation. Additionally, the fabricated metamaterials can be protected by a transparent polymer thin layer for ambient use with further improved color performance. The demonstrated structural color printing with aluminum plasmonic metamaterials offers great potential for relevant applications such as security marking and information storage.

  12. Development of deep drawn aluminum piston tanks

    Energy Technology Data Exchange (ETDEWEB)

    Whitehead, J.C.; Bronder, R.L.; Kilgard, L.W.; Evans, M.C.; Ormsby, A.E.; Spears, H.R.; Wilson, J.D.

    1990-06-08

    An aluminum piston tank has been developed for applications requiring lightweight, low cost, low pressure, positive-expulsion liquid storage. The 3 liter (183 in{sup 3}) vessel is made primarily from aluminum sheet, using production forming and joining operations. The development process relied mainly on pressurizing prototype parts and assemblies to failure, as the primary source of decision making information for driving the tank design toward its optimum minimum-mass configuration. Critical issues addressed by development testing included piston operation, strength of thin-walled formed shells, alloy choice, and joining the end cap to the seamless deep drawn can. 9 refs., 8 figs.

  13. The Reaction of Carbonates in Contact with Superheated Silicate Melts: New Insights from MEMIN Laser Melting Experiments

    Science.gov (United States)

    Hamann, C.; Hecht, L.; Schäffer, S.; Deutsch, A.; Lexow, B.

    2016-08-01

    The reaction of carbonates in contact with silicate impact melts is discussed quite controversially in the impact community. Here, we discuss four MEMIN laser melting experiments involving carbonates in contact with superheated silicate melts.

  14. Modern trends and challenges of development of global aluminum industry

    Directory of Open Access Journals (Sweden)

    M. N. Dudin

    2017-12-01

    Full Text Available This article overviews complex study into modern trends and challenges of development of global aluminum industry. Dynamics, structure, and segmentation of global aluminum market are discussed in terms of systematic analysis. On this basis strategic map of the industry has been plotted and five forces of competition on global aluminum market have been determined which will influence directly on functioning and development of aluminum producing companies.

  15. Sunshine Group Builds High-End Aluminum Product Industrial Base

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    In order to propel development of the aluminum industry to move toward featured,specialized,and ecological directions,Sunlight Sanyuan Aluminum Company plans to expropriate 300 mu of land in Hanjiang District of Putian City,Fujian province,where it plans to construct high-end aluminum product industrial park,introduce the world’s most advanced fully automatic production equipment and technologies for aluminum profile and

  16. Shrinking core models applied to the sodium silicate production process

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2007-01-01

    Full Text Available The sodium silicate production process, with the molar ratio SiO2/Na2O = 2, for detergent zeolite 4A production, is based on quartz sand dissolving in NaOH aqueous solution, with a specific molality. It is a complex process performed at high temperature and pressure. It is of vital importance to develop adequate mathematical models, which are able to predict the dynamical response of the process parameters. A few kinetic models were developed within this study, which were adjusted and later compared to experimental results. It was assumed that SiO2 particles are smooth spheres, with uniform diameter. This diameter decreases during dissolving. The influence of particle diameter, working temperature and hydroxide ion molality on the dissolution kinetics was investigated. It was concluded that the developed models are sufficiently correct, in the engineering sense, and can be used for the dynamical prediction of process parameters.

  17. Photoluminescence in amorphous MgSiO_3 silicate

    CERN Document Server

    Thompson, S P; Day, S J; Connor, L D; Evans, A

    2013-01-01

    Samples of amorphous MgSiO_3 annealed at temperature steps leading up to their crystallisation temperature show a rise in photoluminescence activity, peaking at ~450C. The photoluminescence band has a main peak at 595nm and a weaker peak at 624nm. We present laboratory data to show that the maximum in photoluminescence activity is related to substantial structural reordering that occurs within a relatively narrow temperature range. We attribute the origin of the photoluminescence to non-bridging oxygen hole centre defects, which form around ordered nano-sized domain structures as a result of the breakup of tetrahedral connectivity in the disordered inter-domain network, aided by the loss of bonded OH. These defects are removed as crystallisation progresses, resulting in the decrease and eventual loss of photoluminescence. Thermally processed hydrogenated amorphous silicate grains could therefore represent a potential carrier of extended red emission.

  18. Reactivity, swelling and aggregation of mixed-size silicate nanoplatelets

    Science.gov (United States)

    Segad, M.; Cabane, B.; Jönsson, Bo

    2015-10-01

    Montmorillonite is a key ingredient in a number of technical applications. However, little is known regarding the microstructure and the forces between silicate platelets. The size of montmorillonite platelets from different natural sources can vary significantly. This has an influence on their swelling behavior in water as well as in salt solutions, particularly when tactoid formation occurs, that is when divalent counterions are present in the system. A tactoid consists of a limited number of platelets aggregated in a parallel arrangement with a constant separation. The tactoid size increases with platelet size and with very small nanoplatelets, ~30 nm, no tactoids are observed irrespectively of the platelet origin and concentration of divalent ions. The formation and dissociation of tactoids seem to be reversible processes. A large proportion of small nanoplatelets in a mixed-size system affects the tactoid formation, reduces the aggregation number and increases the extra-lamellar swelling in the system.

  19. S-Isotope Fractionation between Fluid and Silicate Melts

    Science.gov (United States)

    Fiege, A.; Holtz, F.; Shimizu, N.; Behrens, H.; Mandeville, C. W.; Simon, A. C.

    2013-12-01

    Large amounts of sulfur (S) can be released from silicate melts during volcanic eruption. Degassing of magma can lead to S-isotope fractionation between fluid and melt. However, experimental data on fluid-melt S-isotope fractionation are scarce and no data exist for silicate melts at temperatures (T) > 1000°C. Recent advances in in situ S-isotope analyses using secondary ion mass spectroscopy (SIMS) enable determinations of the isotopic composition in silicate glasses with low S content [1] and allow us to investigate experimentally fluid-melt S-isotope fractionation effects in magmatic systems. Isothermal decompression experiments were conducted in internally heated pressure vessels (IHPV). Volatile-bearing (~3 to ~8 wt% H2O, 140 to 2700 ppm S, 0 to 1000 ppm Cl) andesitic and basaltic glasses were synthesized at ~1040°C, ~500 MPa and log(fO2) = QFM to QFM+4 (QFM: quartz-magnetite-fayalite buffer). The decompression experiments were carried out at T = 1030 to 1200°C and similar fO2. Pressure (P) was released continuously from ~400 MPa to 150, 100 or 70 MPa with rates (r) ranging from 0.001 to 0.2 MPa/s. The samples were either rapidly quenched after decompression or annealed for various times (tA) at final conditions (1 to 72 h) before quenching. The volatile-bearing starting glasses and the partially degassed experimental glasses were analyzed by electron microprobe (e.g. Cl-, S-content), IR-spectroscopy (H2O content) and SIMS (δ34S). The gas-melt isotope fractionation factors (αg-m) were estimated following Holloway and Blank [2] and utilizing mass balance calculations. The results show that αg-m remains constant within error over the investigated range of r and tA, reflecting fluid-melt equilibrium fractionation of S isotopes for given T and fO2. Data obtained for oxidizing conditions (~QFM+4) are in agreement with observations in arc magmas [3] and close to what is predicted by previous theoretical and experimental data [4; 5; 6]; e.g. a α(SO2 gas - SO42

  20. Photostable Solid Dispersion of Nifedipine by Porous Calcium Silicate.

    Science.gov (United States)

    Fujimoto, Yumi; Hirai, Nobuaki; Takatani-Nakase, Tomoka; Takahashi, Koichi

    2016-01-01

    Nifedipine (NIF) is a typical light-sensitive drug requiring protection from light during manufacture, storage, and handling of its dosage forms. The purpose of this study was to evaluate the utility of porous calcium silicate (PCS) for maintaining the photostability of NIF in a solid dispersion formulation. Adsorption solid dispersion (ASD) prepared using NIF and PCS as an amorphous formulation was more stable to light irradiation than a physical mixture of NIF and microcrystalline cellulose (a control physical mixture) as a crystalline formulation. In addition, PCS in physical mixtures with NIF adequately protected NIF from photodegradation, suggesting that this protective effect could be because of some screening effect by the porous structure of PCS blocking the passage of light reaching NIF in pores of PCS. These findings suggest that PCS is useful for improving the solubility and photostability of NIF in solid dispersion formulation.

  1. High-dose dosimetry using natural silicate minerals

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Lucas S. do; Mendes, Leticia, E-mail: isatiro@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Watanabe, Shigueo; Rao, Gundu; Lucas, Natasha; Sato, Karina, E-mail: lacifid@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica. Departamento de Fisica Nuclear; Barbosa, Renata F., E-mail: profcelta@hotmail.com [Universidade Federal de Sao Paulo (UNIFESP), Santos, SP (Brazil). Departamento de Ciencias do Mar

    2015-07-01

    In the present study, certain natural silicate minerals such as aquamarine (AB), morganite (PB), goshenite (WB), white jadeite (JW), green jadeite (JG), pink tourmaline (PT) and two varieties of jadeite-like quartz, denoted here by JQ1 and JQ2, were investigated using the thermoluminescence technique to evaluate their potential for use as very-high- and high-dose dosimeters. These minerals respond to high doses of γ-rays of up to 1000 kGy and often to very high doses of up to 3000 kGy. The TL response of these minerals may be considered to be satisfactory for applications in high-dose dosimetry. Investigations of electron paramagnetic resonance and optically stimulated luminescence dosimetry are in progress. (author)

  2. Effects of Silicate, Phosphate, and Calcium on the Stability of Aldopentoses.

    Science.gov (United States)

    Nitta, Sakiko; Furukawa, Yoshihiro; Kakegawa, Takeshi

    2016-06-01

    Ribose is an important constituent of RNA: ribose connects RNA bases and forms a strand of sugar phosphates. Accumulation of ribose on prebiotic Earth was difficult because of its low stability. Improvement in the yield of ribose by the introduction of borate or silicate in a formose-like reaction has been proposed. The effects of borates have been further analyzed and confirmed in subsequent studies. Nonetheless, the effects of silicates and phosphates remain unclear. In the present study, we incubated aldopentoses in a highly alkaline aqueous solution at a moderate temperature to determine the effects of silicate or phosphate on the degradation rates of ribose and its isomeric aldopentoses. The formation of a complex of silicate (or phosphate) with ribose was also analyzed in experiments with (29)Si and (31)P nuclear magnetic resonance (NMR). We found that silicate or phosphate complexes of ribose were not detectable under our experimental conditions. The stability of ribose and lyxose improved after addition of 40-fold molar excess (relative to a pentose) of sodium silicate or sodium phosphate to the alkaline solution. The stability was not improved further when an 80-fold molar excess of sodium silicate or sodium phosphate was added. Calcium was removed from these solutions by precipitation of calcium salts. The drop in Ca(2+) concentration might have improved the stability of ribose and lyxose, which are susceptible to aldol addition. The improvement of ribose stability by the removal of Ca(2+) and by addition of silicate or phosphate was far smaller than the improvement by borate. Furthermore, all aldopentoses showed similar stability in silicate- and phosphate-containing solutions. These results clearly show that selective stabilization of ribose by borate cannot be replaced by the effects of silicate or phosphate; this finding points to the importance of borate in prebiotic RNA formation.

  3. A-thermal elastic behavior of silicate glasses.

    Science.gov (United States)

    Rabia, Mohammed Kamel; Degioanni, Simon; Martinet, Christine; Le Brusq, Jacques; Champagnon, Bernard; Vouagner, Dominique

    2016-02-24

    Depending on the composition of silicate glasses, their elastic moduli can increase or decrease as function of the temperature. Studying the Brillouin frequency shift of these glasses versus temperature allows the a-thermal composition corresponding to an intermediate glass to be determined. In an intermediate glass, the elastic moduli are independent of the temperature over a large temperature range. For sodium alumino-silicate glasses, the a-thermal composition is close to the albite glass (NaAlSi3O8). The structural origin of this property is studied by in situ high temperature Raman scattering. The structure of the intermediate albite glass and of silica are compared at different temperatures between room temperature and 600 °C. When the temperature increases, it is shown that the high frequency shift of the main band at 440 cm(-1) in silica is a consequence of the cristobalite-like alpha-beta transformation of 6-membered rings. This effect is stronger in silica than bond elongation (anharmonic effects). As a consequence, the elastic moduli of silica increase as the temperature increases. In the albite glass, the substitution of 25% of Si(4+) ions by Al(3+) and Na(+) ions decreases the proportion of SiO2 6-membered rings responsible for the silica anomaly. The effects of the silica anomaly balance the anharmonicity in albite glass and give rise to an intermediate a-thermal glass. Different networks, formers or modifiers, can be added to produce different a-thermal glasses with useful mechanical or chemical properties.

  4. Low Velocity Sphere Impact of a Soda Lime Silicate Glass

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Fox, Ethan E [ORNL; Morrissey, Timothy G [ORNL; Vuono, Daniel J [ORNL

    2011-10-01

    This report summarizes TARDEC-sponsored work at Oak Ridge National Laboratory (ORNL) during the FY11 involving low velocity (< 30 m/s or < 65 mph) ball impact testing of Starphire soda lime silicate glass. The intent was to better understand low velocity impact response in the Starphire for sphere densities that bracketed that of rock. Five sphere materials were used: borosilicate glass, soda-lime silicate glass, steel, silicon nitride, and alumina. A gas gun was fabricated to produce controlled velocity delivery of the spheres against Starphire tile targets. Minimum impact velocities to initiate fracture in the Starphire were measured and interpreted in context to the kinetic energy of impact and the elastic property mismatch between the any of the five sphere-Starphire-target combinations. The primary observations from this low velocity (< 30 m/s or < 65 mph) testing were: (1) Frictional effects contribute to fracture initiation. (2) Spheres with a lower elastic modulus require less force to initiate fracture in the Starphire than spheres with a higher elastic modulus. (3) Contact-induced fracture did not initiate in the Starphire SLS for impact kinetic energies < 150 mJ. Fracture sometimes initiated or kinetic energies between {approx} 150-1100 mJ; however, it tended to occur when lower elastic modulus spheres were impacting it. Contact-induced fracture would always occur for impact energies > 1100 mJ. (4) The force necessary to initiate contact-induced fracture is higher under dynamic or impact conditions than it is under quasi-static indentation conditions. (5) Among the five used sphere materials, silicon nitride was the closest match to 'rock' in terms of both density and (probably) elastic modulus.

  5. Evaluation of apatite silicates as solid oxide fuel cell electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Marrero-Lopez, D. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain); Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Martin-Sedeno, M.C.; Aranda, M.A.G. [Dpto. de Quimica Inorganica, Universidad Malaga, 29071 Malaga (Spain); Pena-Martinez, J. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Instituto de Energias Renovables, Parque Tecnologico, Universidad de Castilla La Mancha, 02006 Albacete (Spain); Ruiz-Morales, J.C.; Nunez, P. [Dpto. de Quimica Inorganica, Universidad de La Laguna, 38200 La Laguna, Tenerife (Spain); Ramos-Barrado, J.R. [Dpto. de Fisica Aplicada I, Laboratorio de Materiales y Superficies (Unidad Asociada al C.S.I.C.), Universidad de Malaga, 29071 Malaga (Spain)

    2010-05-01

    Apatite-type silicates have been considered as promising electrolytes for Solid Oxide Fuel Cells (SOFC); however studies on the potential use of these materials in SOFC devices have received relatively little attention. The lanthanum silicate with composition La{sub 10}Si{sub 5.5}Al{sub 0.5}O{sub 26.75} has been evaluated as electrolyte with the electrode materials commonly used in SOFC, i.e. manganite, ferrite and cobaltite as cathode materials and NiO-CGO composite, chromium-manganite and Sr{sub 2}MgMoO{sub 6} as anode materials. Chemical compatibility, area-specific resistance and fuel cell studies have been performed. X-ray powder diffraction (XRPD) analysis did not reveal any trace of reaction products between the apatite electrolyte and most of the aforementioned electrode materials. However, the area-specific polarisation resistance (ASR) of these electrodes in contact with apatite electrolyte increased significantly with the sintering temperature, indicating reactivity at the electrolyte/electrode interface. On the other hand, the ASR values are significantly improved using a ceria buffer layer between the electrolyte and electrode materials to prevent reactivity. Maximum power densities of 195 and 65 mWcm{sup -2} were obtained at 850 and 700 C, respectively in H{sub 2} fuel, using an 1 mm-thick electrolyte, a NiO-Ce{sub 0.8}Gd{sub 0.2}O{sub 1.9} composite as anode and La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} as cathode materials. This fuel cell was tested for 100 h in 5%H{sub 2}-Ar atmosphere showing stable performance. (author)

  6. Shanxi Zhaofeng Aluminum Industry is Planning Oversea Listing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>Shanxi Yangquan Coal Industry(Group)Co., Ltd.intends to promote its subsidiary company Shanxi Zhaofeng Aluminum Metallurgy Co Ltd (hereinafter referred to as Zhaofeng Aluminum Metallurgy)to seek oversea listing.If its effort succeeds,Zhaofeng Aluminum Metallurgy will become the third public listed company under Yangquan Group.

  7. 21 CFR 582.1781 - Sodium aluminum phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sodium aluminum phosphate. 582.1781 Section 582.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Additives § 582.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate. (b) Conditions...

  8. 21 CFR 182.1781 - Sodium aluminum phosphate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium aluminum phosphate. 182.1781 Section 182.1781 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Substances § 182.1781 Sodium aluminum phosphate. (a) Product. Sodium aluminum phosphate....

  9. [Science and Technology and Recycling: Instructional Materials on Aluminum.

    Science.gov (United States)

    Aluminum Association, New York, NY.

    Educational materials on the manufacture and use of aluminum are assembled in this multi-media unit for use by junior high and secondary school students. Student booklets and brochures include: "The Story of Aluminum,""Uses of Aluminum,""Independent Study Guide for School Research Projects,""Questions and Answers About Litter, Solid Waste, and…

  10. 2009 China’s Aluminum Fabrication Industrial Development Report

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>1 Overview of Aluminum Fabrication Industry Despite the impact of 2008’s financial crisis on China’s aluminum fabrication industry, China’s output of aluminum products remained the world’s largest in 2009, against overall steady

  11. New Tax Rebate Policy Favorable to Aluminum Processing Industry

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>China has made the decision to increase export tax rebate rate for part of the non-ferrous products from April 1, 2009, among which the export tax rebate for aluminum alloy hollow profiles and other aluminum alloy profiles goes up to 13%. The new policy is a piece of good news for aluminum processing

  12. 21 CFR 73.1015 - Chromium-cobalt-aluminum oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Chromium-cobalt-aluminum oxide. 73.1015 Section 73... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1015 Chromium-cobalt-aluminum oxide. (a) Identity. The color additive chromium-cobalt-aluminum oxide is a blue-green pigment obtained by calcining...

  13. Shanxi Will Build Aluminum Deep Processing Industrial Park

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    As a province with high coal output,Shanx boasts rich electrolytic aluminum resources.On January 7,the reporter learned from the Provincial Commission of Economy and Information Technology that in order to continually expand the size of aluminum industry,extend aluminum industrial chain,so

  14. Status Quo of China’s Aluminum Sheet & Strip Industry

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>Aluminum sheet & strip products are one of the major product varieties in the aluminum processing industry, they also provide indis-pensable basic materials for the development of national economy. In recent years, driven by rapid economic growth, China’s investment in aluminum sheet & strip industry continued to

  15. A Study of Siliceous Pneumoconiosis in a Desert Area of Sunan County,Gansu Province,China

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    Three hundred and ninety five residents in a desert area were examined with chest radiographs and 28 cases with siliceous pneumoconiosis were found.The prevalence of siliceous pneumoconiosis was 7.09%,and that over 40 years of age was 21%.The histological findings of lungs from a camel living in that area for 20 years also confirmed to have siliceous pneumoconiosis.

  16. 40 CFR 721.3100 - Oligomeric silicic acid ester compound with a hy-droxyl-al-kyla-mine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oligomeric silicic acid ester compound... Significant New Uses for Specific Chemical Substances § 721.3100 Oligomeric silicic acid ester compound with a... chemical substance identified generically as oligomeric silicic acid ester compound with...

  17. Loften Aluminum Aluminum Foil Output to Reach 120,000 Tons in 2012

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>Loften Aluminum Co., Ltd. was founded in 2000 Boxing County, Shandong Province. On 31 March 2010, Loften became an A-share listed company, creating favorable conditions for raising funds to expand its operations.

  18. CPI Challenges CHINALCO in Aluminum Business

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>China Power Investment Corporation (hereinafter referred to as CPI),one of the top 5 power generation groups,grows rapidly in aluminum business,making CHINALCO (hereinafter re-ferred to as CHINALCO),the traditional No.1

  19. Inelastic Deformation Analysis of Aluminum Bending Members

    Institute of Scientific and Technical Information of China (English)

    CHENG Ming; SHI Yongjiu; WANG Yuanqing

    2006-01-01

    Aluminum alloys are typical nonlinear materials, and consequently bending members made of this material exhibit a nonlinear behavior. Most design codes do not pay much attention to such deformations and adopt a simple linear analysis for the calculation of deflections. This paper presents an investigation of the nonlinear deformation of aluminum bending members using the finite-element analysis (FEA). The plastic adaptation coefficient, which can be used to limit the residual deflection, is introduced, and the influence of residual deflection is investigated. A method for evaluating the plastic adoption coefficient is proposed. This paper also shows the load-deflection curve of aluminum bending members and the influence of several parameters. A semi-empirical formula is derived, and some numerical examples are given by FEA. The coefficients of the semi-empirical formula are modified by the FEA results using the nonlinear fitting method. Based on these results, two improved design methods for strength and deformation of aluminum bending members are proposed. Through the comparison with test data, these methods are proved to be suitable for structural design.

  20. 75 FR 80527 - Aluminum Extrusions From China

    Science.gov (United States)

    2010-12-22

    ... Republic of China: Postponement of Final Determination of Sales at Less Than Fair Value, 75 FR 73041... Sales at Less Than Fair Value, and Preliminary Determination of Targeted Dumping, 75 FR 69403, November... Affirmative Countervailing Duty Determination, 75 FR 54302, September 7, 2010, and Aluminum Extrusions...

  1. Absorptive coating for aluminum solar panels

    Science.gov (United States)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  2. Molybdate Coatings for Protecting Aluminum Against Corrosion

    Science.gov (United States)

    Calle, Luz Marina; MacDowell, Louis G.

    2005-01-01

    Conversion coatings that comprise mixtures of molybdates and several additives have been subjected to a variety of tests to evaluate their effectiveness in protecting aluminum and alloys of aluminum against corrosion. Molybdate conversion coatings are under consideration as replacements for chromate conversion coatings, which have been used for more than 70 years. The chromate coatings are highly effective in protecting aluminum and its alloys against corrosion but are also toxic and carcinogenic. Hexavalent molybdenum and, hence, molybdates containing hexavalent molybdenum, have received attention recently as replacements for chromates because molybdates mimic chromates in a variety of applications but exhibit significantly lower toxicity. The tests were performed on six proprietary formulations of molybdate conversion coatings, denoted formulations A through F, on panels of aluminum alloy 2024-T3. A bare alloy panel was also included in the tests. The tests included electrochemical impedance spectroscopy (EIS), measurements of corrosion potentials, scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS), and x-ray photoelectron spectroscopy (XPS).

  3. High Energy Density aluminum/oxygen cell

    Science.gov (United States)

    Rudd, E. J.; Gibbons, D. W.

    An alternative to a secondary battery as the power source for vehicle propulsion is a fuel cell, an example of which is the metal/air cell using metals such as aluminum, zinc, or iron. Aluminum is a particularly attractive candidate, with high energy and power densities, environmentally acceptable and having a large, established industrial base for production and distribution. An aluminum/oxygen system is currently under development for a prototype unmanned, undersea vehicle (UUV) for the US navy and recent work has focussed upon low corrosion aluminum alloys, and an electrolyte management system for processing the by-products of the energy-producing reactions. This paper summarizes the progress made in both areas. Anode materials capable of providing high utilization factors over current densities ranging from 5 to 150 mA/cm 2 have been identified, such materials being essential to realize mission life for the UUV. With respect to the electrolyte management system, a filter/precipitator unit has been successfully operated for over 250 h in a large scale, half-cell system.

  4. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  5. Laser micro welding of copper and aluminum

    Science.gov (United States)

    Mys, Ihor; Schmidt, Michael

    2006-02-01

    Aluminum combines comparably good thermal and electrical properties with a low price and a low material weight. These properties make aluminum a promising alternative to copper for a large number of electronic applications, especially when manufacturing high volume components. However, a main obstacle for a wide use of this material is the lack of a reliable joining process for the interconnection of copper and aluminum. The reasons for this are a large misalignment in the physical properties and even more a poor metallurgical affinity of both materials that cause high crack sensitivity and the formation of brittle intermetallic phases during fusion welding. This paper presents investigations on laser micro welding of copper and aluminum with the objective to eliminate brittle intermetallic phases in the welding structure. For these purposes a combination of spot welding, a proper beam offset and special filler material are applied. The effect of silver, nickel and tin filler materials in the form of thin foils and coatings in a thickness range 3-100 μm has been investigated. Use of silver and tin filler materials yields to a considerable improvement of the static and dynamic mechanical stability of welded joints. The analysis of the weld microstructure shows that an application even of small amounts of suitable filler materials helps to avoid critical, very brittle intermetallic phases on the interface between copper and solidified melt in the welded joints.

  6. UV fluorescence enhancement from nanostructured aluminum materials

    Science.gov (United States)

    Montanari, Danielle E.; Dean, Nathan; Poston, Pete E.; Blair, Steve; Harris, Joel M.

    2016-09-01

    Interest in label-free detection of biomolecules has given rise to the need for UV plasmonic materials. DNA bases and amino acid residues have electronic resonances in the UV which allow for sensitive detection of these species by surface-enhanced UV fluorescence spectroscopy. Electrochemical roughening has been used extensively to generate plasmonically-active metal surfaces that produce localized enhancement of excitation and emission of electromagnetic radiation from surface-bound molecules. Electrochemically roughened gold and silver surfaces produce enhancement in the visible and near-IR regions, but to the best of our knowledge, application of this technique for producing UV-enhancing substrates has not been reported. Using electropolishing of aluminum, we are able to generate nanostructured surfaces that produce enhanced spectroscopic detection of molecules in the UV. Aluminum is a natural choice for substrate composition as it exhibits a relatively large quality factor in the UV. We have fabricated electropolished aluminum films with nanometer scale roughness and have studied UV-excited fluorescence enhancement from submonolayer coverage of tryptophan on these substrates using a UV-laser based spectrometer. Quantitative dosing by dip-coating was used to deposit known surface concentrations of the aromatic amino acid tryptophan, so that fluorescence enhancement could be evaluated. Compared to a dielectric substrate (surface-oxidized silicon), we observe a 180-fold enhancement in the total fluorescence emitted by tryptophan on electropolished aluminum under photobleaching conditions, allowing detection of sub-monolayer coverages of molecules essential for development of biosensor technologies.

  7. Low absorptance porcelain-on-aluminum coating

    Science.gov (United States)

    Leggett, H.

    1979-01-01

    Porcelain thermal-control coating for aluminum sheet and foil has solar absorptance of 0.22. Specially formulated coating absorptance is highly stable, changing only 0.03 after 1,000 hours of exposure to simulated sunlight and can be applied by standard commercial methods.

  8. Optical properties of ALON (aluminum oxynitride)

    Science.gov (United States)

    Hartnett, T. M.; Bernstein, S. D.; Maguire, E. A.; Tustison, R. W.

    1998-06-01

    The optical properties of ALON (aluminum oxynitride) are presented. Optical scatter and index of refraction, and absorption of several different compositions of ALON are compared. The temperature dependence of emissivity of ALON was measured in the temperature range 46°C to 1200°C.

  9. Aluminum Foil and Aluminum Sheet Project with the Total Investment of RMB 1 billion Officially Launched in Wanshan

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>According the news report on February 25,Wanshan district and Galaxy Aluminum Co.,Ltd. in Shengzhou,Zhejiang province signed an agreement on aluminum foil and aluminum sheet production on February 19 in Sanya,Hainan province,a sign that the project is offi- cially established in Wanshan.

  10. Hangzhou Jinjiang Group Shanxi Fusheng Aluminum Phase I 800,000 t/a Aluminum Oxide Project Started Operation

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>On October 19,the Shanxi Province Pinglu County Phase I 800,000t/a Aluminum Oxide Project of Shanxi Fusheng Aluminum Co.,Ltd,a subordinate of Hangzhou Jinjiang Group,started operation.This is the fourth Aluminum oxide project constructed and operated by Jinjiang Group.

  11. Investigation of Methods for Selectively Reinforcing Aluminum and Aluminum-Lithium Materials

    Science.gov (United States)

    Bird, R. Keith; Alexa, Joel A.; Messick, Peter L.; Domack, Marcia S.; Wagner, John A.

    2013-01-01

    Several studies have indicated that selective reinforcement offers the potential to significantly improve the performance of metallic structures for aerospace applications. Applying high-strength, high-stiffness fibers to the high-stress regions of aluminum-based structures can increase the structural load-carrying capability and inhibit fatigue crack initiation and growth. This paper discusses an investigation into potential methods for applying reinforcing fibers onto the surface of aluminum and aluminum-lithium plate. Commercially-available alumina-fiber reinforced aluminum alloy tapes were used as the reinforcing material. Vacuum hot pressing was used to bond the reinforcing tape to aluminum alloy 2219 and aluminum-lithium alloy 2195 base plates. Static and cyclic three-point bend testing and metallurgical analysis were used to evaluate the enhancement of mechanical performance and the integrity of the bond between the tape and the base plate. The tests demonstrated an increase in specific bending stiffness. In addition, no issues with debonding of the reinforcing tape from the base plate during bend testing were observed. The increase in specific stiffness indicates that selectively-reinforced structures could be designed with the same performance capabilities as a conventional unreinforced structure but with lower mass.

  12. Removal of Aluminum from Water and Industrial Waste Water

    Directory of Open Access Journals (Sweden)

    Parisa Ghashghaiee pour

    2014-09-01

    Full Text Available This study attempts to introduce a procedure to remove Aluminum ions from drinking water and industrial effluents by using active carbon with different grading as absorbent. Absorption of Aluminum ions were discussed in different conditions of Aluminum concentration, contact time, impact of electrolytes and pH on Aluminum ions absorbency. Both Freundlich and Langmuir isotherms used to investigate the adsorption. Thermodynamics relations governing process, such as specification of ( , ( and the enthalpy of adsorption, were calculated, which showed that Aluminum absorption on active carbon is an endothermic and spontaneous process.

  13. Preparation of Ultra-fine Aluminum Nitride in Thermal Plasma

    Institute of Scientific and Technical Information of China (English)

    漆继红; 罗义文; 印永祥; 代晓雁

    2002-01-01

    Ultra-fine aluminum nitride has been synthesized by the evaporation of aluminum powder at atmospheric-pressure nitrogen plasma in a hot-wall reactor. The average size of aluminum nitride particle is 0.11μm measured by scanning electric mirror (SEM), and the purity is at least over 90% evaluated by X-Ray diffraction (XRD). The conversion of Al powder to aluminum nitride is strongly depended on the injection of NH3. Typical experimental parameters such as the feed rate of raw material, the flow rate of ammonia and the position of injecting aluminum powder into the reactor are given.

  14. Predicting the residual aluminum level in water treatment process

    OpenAIRE

    J. Tomperi; M. Pelo; K. Leiviskä

    2012-01-01

    In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP) was analyzed and the residual aluminum in drinking water was predicted usin...

  15. Predicting the residual aluminum level in water treatment process

    OpenAIRE

    J. Tomperi; M. Pelo; K. Leiviskä

    2013-01-01

    In water treatment processes, aluminum salts are widely used as coagulation chemical. High dose of aluminum has been proved to be at least a minor health risk and some evidence points out that aluminum could increase the risk of Alzheimer's disease. Thus it is important to minimize the amount of residual aluminum in drinking water and water used at food industry. In this study, the data of a water treatment plant (WTP) was analyzed and the residual aluminum in drinking water was predicted usi...

  16. Rheology of suspensions with aluminum nano-particles

    Directory of Open Access Journals (Sweden)

    Ulrich Teipel

    2009-01-01

    Full Text Available Nano-scale aluminum particles are innovative materials increasingly used in energetic formulations. In this contribution, the rheological behavior of suspensions with either paraffin oil or HTPB as the matrix fluid and nano-scale aluminum (ALEX as the dispersed phase is described and discussed. The paraffin oil/aluminum suspensions exhibit non-Newtonian flow behavior over a wide range of concentrations, whereas the HTPB/aluminum suspensions exhibitNewtonian behavior (i.e. the viscosity is independent of shear stress up to a concentration of 50 vol.% aluminum. Both systems have unusual viscoelastic properties in that their elastic moduli are independent of the solids concentration.

  17. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill L Part 1

    Institute of Scientific and Technical Information of China (English)

    M. Kermani; F.P. Hassani; E. Aflaki; M. Benzaazoua; M. Nokken

    2015-01-01

    In this paper, the mechanical properties of sodium silicate-fortified backfill, called Gelfill, were investi-gated by conducting a series of laboratory experiments. Two configurations were tested, i.e. Gelfill and cemented hydraulic fill (CHF). The Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of mine backfill which are tailings, water and binders. Large numbers of samples of Gelfill and CHF with various mixture designs were cast and cured for over 28 d. The me-chanical properties of samples were investigated using uniaxial compression test, and the results were compared with those of reference samples made without sodium silicate. The test results indicated that the addition of an appropriate amount of an alkali activator such as sodium silicate can enhance the mechanical (uniaxial compressive strength) and physical (water retention) properties of backfill. The microstructure analysis conducted by mercury intrusion porosimetry (MIP) revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill, which can contribute to the better mechanical properties of Gelfill. It was also shown that the time and rate of drainage in the Gelfill specimens are less than those in CHF specimens made without sodium silicate. Finally, the study showed that the addition of sodium silicate can reduce the required setting time of mine backfill, which can contribute to increase mine production in accordance with the mine safety.

  18. Nonmare volcanism on the Moon: Photometric evidence for the presence of evolved silicic materials

    Science.gov (United States)

    Clegg-Watkins, R. N.; Jolliff, B. L.; Watkins, M. J.; Coman, E.; Giguere, T. A.; Stopar, J. D.; Lawrence, S. J.

    2017-03-01

    Images and photometric data from the Lunar Reconnaissance Orbiter Camera (LROC) Narrow Angle Cameras (NACs) are used to investigate regions of the Moon inferred from previous remote sensing compositional studies to be associated with nonmare, silicic volcanics. Specifically, LROC NAC imagery, with photometry normalized to account for local slopes using NAC Digital Terrain Models (DTMs), was used to investigate the exposed areas associated with the Compton-Belkovich Volcanic Complex (CBVC), Hansteen Alpha Volcanic Complex (HAVC), Lassell Massif (LM), Gruithuisen Domes (GD), and ejecta of Aristarchus Crater (AC). Photometric studies of spacecraft landing sites, for which ground-truth compositional data exist, allow us to study the relationship between photometric properties of soils and their mineralogical and chemical compositions. The silicic regions have high reflectance and single scattering albedos that are consistent with different proportions of highly reflective minerals including alkali feldspar and quartz, and low concentrations of mafic minerals. Of the silicic sites studied, the CBVC has the highest reflectance values and single scattering albedos. Silicic pyroclastic deposits may also occur at the CBVC, and we present evidence from laboratory spectra that an addition of up to ∼20 wt% glassy silicic materials to a highlands-type regolith simulant can account for the increased reflectance of these volcanic regions. Reflectance variations across and within the sites can be explained by mixing of felsic mineral components, evolved-to-intermediate silicic compositions, and/or silicic pyroclastic deposits.

  19. Effect of silicate incorporation on in vivo responses of α-tricalcium phosphate ceramics.

    Science.gov (United States)

    Kamitakahara, Masanobu; Tatsukawa, Eri; Shibata, Yasuaki; Umemoto, Shota; Yokoi, Taishi; Ioku, Koji; Ikeda, Tohru

    2016-05-01

    In addition to calcium phosphate-based ceramics, glass-based materials have been utilized as bone substitutes, and silicate in these materials has been suggested to contribute to their ability to stimulate bone repair. In this study, a silicate-containing α-tricalcium phosphate (α-TCP) ceramic was prepared using a wet chemical process. Porous granules composed of silicate-containing α-TCP, for which the starting composition had a molar ratio of 0.05 for Si/(P + Si), and silicate-free α-TCP were prepared and evaluated in vivo. When implanted into bone defects that were created in rat femurs, α-TCP ceramics either with or without silicate were biodegraded, generating a hybrid tissue composed of residual ceramic granules and newly formed bone, which had a tissue architecture similar to physiological trabecular structures, and aided regeneration of the bone defects. Supplementation with silicate significantly promoted osteogenesis and delayed biodegradation of α-TCP. These results suggest that silicate-containing α-TCP is advantageous for initial skeletal fixation and wound regeneration in bone repair.

  20. Probing Interstellar Silicate Dust Grain Properties in Quasar Absorption Systems at Redshifts z<1.4

    CERN Document Server

    Aller, Monique C; York, Donald G; Welty, Daniel E; Vladilo, Giovanni; Som, Debopam

    2014-01-01

    Absorption lines in the spectra of distant quasars whose sightlines pass through foreground galaxies provide a valuable tool to probe the dust and gas compositions of the interstellar medium (ISM) in galaxies. The first evidence of silicate dust in a quasar absorption system (QAS) was provided through our detection of the 10 micron silicate feature in the z=0.52 absorber toward the quasar AO 0235+164. We present results from 2 follow-up programs using archival Spitzer Space Telescope infrared spectra to study the interstellar silicate dust grain properties in a total of 13 QASs at 0.1silicate feature in the QASs studied. We also detect the 18 micron silicate feature in the sources with adequate spectral coverage. We find variations in the breadth, peak wavelength, and substructure of the 10 micron interstellar silicate absorption features among the absorbers. This suggests that the silicate dust grain properties in these distant galaxies may differ relat...

  1. Valence determination of rare earth elements in lanthanide silicates by L 3-XANES spectroscopy

    Science.gov (United States)

    Kravtsova, Antonina N.; Guda, Alexander A.; Goettlicher, Joerg; Soldatov, Alexander V.; Taroev, Vladimir K.; Kashaev, Anvar A.; Suvorova, Lyudmila F.; Tauson, Vladimir L.

    2016-05-01

    Lanthanide silicates have been hydrothermally synthesized using Cu and Ni containers. Chemical formulae of the synthesized compounds correspond to K3Eu[Si6O15] 2H2O, HK6Eu[Si10O25], K7Sm3[Si12O32], K2Sm[AlSi4O12] 0.375H2O, K4Yb2[Si8O21], K4Ce2[Al2Si8O24]. The oxidation state of lanthanides (Eu, Ce, Tb, Sm, Yb) in these silicates has been determined using XANES spectroscopy at the Eu, Ce, Tb, Sm, Yb, L 3- edges. The experimental XANES spectra were recorded using the synchrotron radiation source ANKA (Karlsruhe Institute of Technology) and the X-ray laboratory spectrometer Rigaku R- XAS. By comparing the absorption edge energies and white line intensities of the silicates with the ones of reference spectra the oxidation state of lanthanides Eu, Ce, Tb, Sm, Yb has been found to be equal to +3 in all investigated silicates except of the Ce-containing silicate from the run in Cu container where the cerium oxidation state ranges from +3 (Ce in silicate apatite and in a KCe silicate with Si12O32 layers) to +4 (starting CeO2 or oxidized Ce2O3).

  2. Evaluation of the effect of sodium silicate addition to mine backfill, Gelfill − Part 1

    Directory of Open Access Journals (Sweden)

    M. Kermani

    2015-06-01

    Full Text Available In this paper, the mechanical properties of sodium silicate-fortified backfill, called Gelfill, were investigated by conducting a series of laboratory experiments. Two configurations were tested, i.e. Gelfill and cemented hydraulic fill (CHF. The Gelfill has an alkali activator such as sodium silicate in its materials in addition to primary materials of mine backfill which are tailings, water and binders. Large numbers of samples of Gelfill and CHF with various mixture designs were cast and cured for over 28 d. The mechanical properties of samples were investigated using uniaxial compression test, and the results were compared with those of reference samples made without sodium silicate. The test results indicated that the addition of an appropriate amount of an alkali activator such as sodium silicate can enhance the mechanical (uniaxial compressive strength and physical (water retention properties of backfill. The microstructure analysis conducted by mercury intrusion porosimetry (MIP revealed that the addition of sodium silicate can modify the pore size distribution and total porosity of Gelfill, which can contribute to the better mechanical properties of Gelfill. It was also shown that the time and rate of drainage in the Gelfill specimens are less than those in CHF specimens made without sodium silicate. Finally, the study showed that the addition of sodium silicate can reduce the required setting time of mine backfill, which can contribute to increase mine production in accordance with the mine safety.

  3. Preparation and Characterization of Lithium Zirconium Silicate for CO2 Capture

    Directory of Open Access Journals (Sweden)

    T.S. Bhosale

    2014-10-01

    Full Text Available The samples of lithium zirconium silicate were prepared by precipitation, template and sol-gel meth-ods. The samples were prepared with several mol ratios of Li:Zr:Si. The preparation of lithium zirco-nium silicate samples by precipitation method were carried out by using the lithium nitrate, zirconyl nitrate, zirconium(IV oxypropoxide and tetramethylorthosilicate (TEOS as precursors. The samples of lithium zirconium silicate were prepared by using cetyltrimethyl-ammonium bromide (C-TAB and tetramethyl ammonium hydroxide (TMAOH by template method. The samples of lithium zirconium silicate were characterized by XRD, TEM, SEM, 29Si-MAS NMR and FTIR. The surface area, alkalinity / acidity of the samples of lithium zirconium silicate were measured. The TGA analysis of lithium zirco-nium silicate samples was done. The CO2 captured by the samples of lithium zirconium silicate was es-timated. The captured CO2 by the samples of lithium zirconium silicate was found to be in the range 3.3 to 8.6 wt%. © 2014 BCREC UNDIP. All rights reservedReceived: 27th March 2014; Revised: 31st July 2014; Accepted: 2nd August 2014How to Cite: Bhosale, T.S. , Gaikwad, A.G. (2014. Preparation and Characterization of Lithium Zirconium Silicate for CO2 Capture. Bulletin of Chemical Reaction Engineering & Catalysis, 9(3: 249-262. (doi:10.9767/bcrec.9.3.6646.249-262Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.6646.249-262

  4. Aluminum Target Dissolution in Support of the Pu-238 Program

    Energy Technology Data Exchange (ETDEWEB)

    McFarlane, Joanna [ORNL; Benker, Dennis [ORNL; DePaoli, David W [ORNL; Felker, Leslie Kevin [ORNL; Mattus, Catherine H [ORNL

    2014-09-01

    Selection of an aluminum alloy for target cladding affects post-irradiation target dissolution and separations. Recent tests with aluminum alloy 6061 yielded greater than expected precipitation in the caustic dissolution step, forming up to 10 wt.% solids of aluminum hydroxides and aluminosilicates. We present a study to maximize dissolution of aluminum metal alloy, along with silicon, magnesium, and copper impurities, through control of temperature, the rate of reagent addition, and incubation time. Aluminum phase transformations have been identified as a function of time and temperature, using X-ray diffraction. Solutions have been analyzed using wet chemical methods and X-ray fluorescence. These data have been compared with published calculations of aluminum phase diagrams. Temperature logging during the transients has been investigated as a means to generate kinetic and mass transport data on the dissolution process. Approaches are given to enhance the dissolution of aluminum and aluminosilicate phases in caustic solution.

  5. CATALOG INFORMATION ON THE PERFORMANCE OF ALUMINUM IN SEA WATER

    Energy Technology Data Exchange (ETDEWEB)

    RH. Wagner and RA. Bonewitz

    1978-04-01

    To help evaluate aluminum alloys for OTEC heat exchanger tubes data on the performance of aluminum in surface and deep sea water has been assembled and computer cataloged. Pitting and crevice corrosion proved to be the types of attack that predominated. The cataloged data are the results of many static tests conducted under natural conditions of marine fouling, hence, they must be used carefully in qualifying aluminum for OTEC purposes. These data can serve the OTEC program best as a basis for selecting aluminum alloys that appear promising as candidates for further evaluation. The aluminum alloys 5052 and Alclad {7072) 3003 fall into this category. Available service histories also proved inadequate for qualifying aluminum alloys for the OTEC application, but they do support the selection of Alclad (7072) 3003 as a tubing alloy worthy of further consideration. Performance data covering areas of investigation peculiar to OTEC power plants is needed to permit a firm decision for or against aluminum alloy tubes.

  6. The distribution of chromium among orthopyroxene, spinel and silicate liquid at atmospheric pressure

    Science.gov (United States)

    Barnes, S. J.

    1986-01-01

    The Cr distributions for a synthetic silicate melt equilibrated with bronzitic orthopyroxene and chromite spinel between 1334 and 1151 C over a range of oxygen fugacities between the nickel-nickel oxide and iron-wuestite buffers are studied. The occurrence, chemical composition, and structure of the orthopyroxene-silicate melt and the spinel-silicate melt are described. It is observed that the Cr content between bronzite and the melt increases with falling temperature along a given oxygen buffer and decreases with falling oxygen fugacity at a given temperature; however, the Cr content of the melt in equilibrium with spinel decreases with falling temperature and increases with lower oxygen fugacity.

  7. Oligo-lysine Induced Formation of Silica Particles in Neutral Silicate Solution

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Oligo-(lysine)n (n = 1-4) containing different numbers of lysine residues was used to induce the condensation of silicic acid to form silica particles in neutral silicate solution. It was found that the condensation rate and the formation of silica particles are dependent on the number of lysine residues in an oligo-lysine. Oligo-lysine with more lysine residues can link more silicic acid together to form a matrix that promotes the effective aggregation of the condensed silica pieces to form large silica particles.

  8. Carbonate Formation in Non-Aqueous Environments by Solid-Gas Carbonation of Silicates

    CERN Document Server

    Day, S J; Evans, A; Parker, J E

    2012-01-01

    We have produced synthetic analogues of cosmic silicates using the Sol Gel method, producing amorphous silicates of composition Mg(x)Ca(1-x)SiO3. Using synchrotron X-ray powder diffraction on Beamline I11 at the Diamond Light Source, together with a newly-commissioned gas cell, real-time powder diffraction scans have been taken of a range of silicates exposed to CO2 under non-ambient conditions. The SXPD is complemented by other techniques including Raman and Infrared Spectroscopy and SEM imaging.

  9. Carbonate formation in non-aqueous environments by solid-gas carbonation of silicates

    Science.gov (United States)

    Day, S. J.; Thompson, S. P.; Evans, A.; Parker, J. E.

    2012-02-01

    We have produced synthetic analogues of cosmic silicates using the Sol Gel method, producing amorphous silicates of composition Mg(x)Ca(1-x)SiO3. Using synchrotron X-ray powder diffraction on Beamline I11 at the Diamond Light Source, together with a newly-commissioned gas cell, real-time powder diffraction scans have been taken of a range of silicates exposed to CO2 under non-ambient conditions. The SXPD is complemented by other techniques including Raman and Infrared Spectroscopy and SEM imaging.

  10. Sorption properties of finely dispersed metal-containing polymer-silicate materials

    Directory of Open Access Journals (Sweden)

    Андрій Сергійович Масюк

    2015-11-01

    Full Text Available Sorption properties of metal-containing polymer-silicate materials on regarding to different acid-base indicators have been investigated. The effect of the nature of metal and polymer modifier (polyvinyl alcohol and polyvinylpyrrolidone on the amount of active centers and specific active surface area of such material was determined. Moisture absorption of modified and not modified silicate fillers was founded. The effect of Ni-containing polymer-silicate fillers on the speed of curing of polyester compositions was determined

  11. Crystallisation mechanism of a multicomponent lithium alumino-silicate glass

    Energy Technology Data Exchange (ETDEWEB)

    Wurth, R. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany); Pascual, M.J., E-mail: mpascual@icv.csic.es [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Mather, G.C.; Pablos-Martin, A.; Munoz, F.; Duran, A. [Instituto de Ceramica y Vidrio, CSIC, Kelsen 5, 28049 Madrid (Spain); Cuello, G.J. [Institut Laue-Langevin, Boite Postale 156, 38042 Grenoble Cedex 9 (France); Ruessel, C. [Otto-Schott-Institut, Jena University, Fraunhoferstr. 6, 07743 Jena (Germany)

    2012-06-15

    A base glass of composition 3.5 Li{sub 2}O Bullet-Operator 0.15 Na{sub 2}O Bullet-Operator 0.2 K{sub 2}O Bullet-Operator 1.15 MgO Bullet-Operator 0.8 BaO Bullet-Operator 1.5 ZnO Bullet-Operator 20 Al{sub 2}O{sub 3} Bullet-Operator 67.2 SiO{sub 2} Bullet-Operator 2.6 TiO{sub 2} Bullet-Operator 1.7 ZrO{sub 2} Bullet-Operator 1.2 As{sub 2}O{sub 3} (in wt.%), melted and provided by SCHOTT AG (Mainz), was used to study the crystallisation mechanism of lithium alumino-silicate glass employing X-ray diffraction combined with neutron diffraction and non-isothermal differential scanning calorimetry (DSC). A high-quartz solid solution of LiAlSi{sub 2}O{sub 6} with nanoscaled crystals forms at 750 Degree-Sign C. Quantitative Rietveld refinement of samples annealed at 750 Degree-Sign C for 8 h determined a crystallised fraction of around 59 wt.%. The room temperature crystallised phase adopts an ordered, {beta}-eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. The Avrami parameter (n {approx} 4), calculated from DSC data using different theoretical approaches, indicates that bulk crystallisation occurs and that the number of nuclei increases during annealing. The activation energy of the crystallisation is 531 {+-} 20 kJ mol{sup -1}. - Highlights: Black-Right-Pointing-Pointer Nanoscaled high-quartz crystals from a multicomponent lithium alumino-silicate glass. Black-Right-Pointing-Pointer Combined X-ray and neutron diffraction structural refinement. Black-Right-Pointing-Pointer {beta}-Eucryptite-like structure (2 Multiplication-Sign 2 Multiplication-Sign 2 cell) with Li ordered in the structural channels. Black-Right-Pointing-Pointer 3-Dimensional bulk crystallisation mechanism with an increasing number of nuclei. Black-Right-Pointing-Pointer Usage and validation of an alternative approach to calculate the Avrami parameter.

  12. Influence of aluminum on the hydrothermal alteration rate of olivine

    Science.gov (United States)

    Andreani, M.; Daniel, I.; Pollet-Villard, M.

    2013-12-01

    The reactivity of ultramafic rocks under hydrothermal conditions controls chemical fluxes at the interface between the internal and external reservoirs of silicate planets. On Earth, hydration of ultramafic rocks is ubiquitous and operates from deep subduction zones to shallow lithospheric environments where it considerably affects the physical and chemical properties of rocks and can interact with the biosphere. This process also has key emerging societal implications, such as the production of hydrogen as a source of carbon-free energy. To date, the chemical model systems used to reproduce olivine hydrothermal alteration lead to the formation of serpentine with sluggish reaction rates. Although aluminum is common in geological environments and in hydrothermal systems in particular, its role in serpentinization or olivine dissolution has not been investigated under hydrothermal conditions. Nevertheless, abundant Al supply is expected in fluids released from dehydration of metapelites in subduction zones as well as during the hydrothermal alteration of gabbros at mid-ocean ridges. Aluminum was also abundant in primitive environments of both the Earth and Mars, stored in either Al-rich minerals like plagioclase or Al-enriched ultramafic lavas. We have investigated the role of Al on the hydrothermal alteration of olivine in a series of experiments performed in a low-pressure diamond anvil cell while following the reaction progress in situ by optical imaging and by confocal Raman spectroscopy. Experiments were run for 4.5 to 7.5 days with two olivine grains reacted in saline water (0.5 molal NaCl) at 200°C and 300°C, and P=200 MPa. After two days, olivine crystals were fully transformed to an aluminous serpentine, also enriched in iron. The very fast precipitation of serpentine may inhibit magnetite nucleation here. However, this does not rule out an H2 production since serpentines classically incorporate non negligible amount of ferric iron in their structure. The

  13. ALUMINUM CONTENT OF TEA LEAVES AND FACTORS AFFECTING THE UPTAKE OF ALUMINUM FROM SOIL INTO TEA LEAVES

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Numerous studies indicated that aluminum, the most abundant metallic element within the lithosphere, was considered to be related to some human diseases especially the Alzheimer's disease. Tea, economically an important beverage in the world, has been found to contain higher concentration of aluminum than many other drinks and foods. Therefore, tea would be a potentially important source of dietary aluminum. In order to understand the sources of aluminum in tea leaves and factors related with aluminum content of tea leaves, an experiment was designed to investigate the relationships of aluminum in tea leaves with leaf age, soil properties and forms of aluminum in soils. The results showed that there were great distinctions in the concentration of aluminum in tea leaves with different leaf age (Alold leaf> Almature leaf> Alyoung leaf). Moreover, soil pH was the major factor controlling the uptake of aluminum from soil into tea leaves. Furthermore, the content of aluminum in tea leaves was better predicated by the soluble aluminum extracted by 0. 02mol/L CaCl2.

  14. MODIFICATION OF SURFACE LAYERS FOR SILICATE GLASSES BY ELECTRON IRRADIATION

    Directory of Open Access Journals (Sweden)

    V. S. Brunov

    2014-05-01

    Full Text Available Experimental research results of silicate glass surface layers modification by the influence of electron beams with 5-50 keV energies and 20-50 mC/cm2 doses are presented. It is shown that during the glasses exposure to an electron beam with 20-50 keV electron energies, a gradient optical waveguide with increased refractive index on waveguide axis Δn = 0.01-0.04 is formed in the surface layer. Сhemical etching rate is increased in the exposed area by up to two times which is related to glass grid destruction. Depending on irradiation dose thin film or silver nanoparticles with the size less than 20nm are formed on the surface of the silver containing glasses for electron energies less than 10 keV. Silver films drawn on the surface of the glass are dissolved into the glass bulk for electron energies 20-50 keV and 20-50 mC/cm2 dose. Basic mechanisms causing these effects are: chemical bonds breaking of spatial glass grid by high energy electrons, formation of negative volume charge inside the glass and field migration of positive metal ions into the volume charge region. Achieved results can be used in photonics, integral optics and nanoplasmonics device fabrication.

  15. O-17 NMR studies of some silicate crystals and glasses

    CERN Document Server

    Yildirim, E K

    2000-01-01

    structure. Therefore some of the Sn has to be in three coordinated to oxygen for charge balancing. The sup 1 sup 7 O MAS NMR spectra of a partially crystallised sample showed three distinct sites which are assigned as Sn-O-Sn, Si-O-Sn, and Si-O-Si on the basis of their chemical shift. The C sub Q values obtained from the simulations of these peaks supports this assignment. The sup 2 sup 9 Si MAS NMR of the same sample showed two crystalline and a glassy peaks which are fitted to two crystalline and two glassy sites. The possible composition of this sample was calculated and found to be SiSn sub 8 O sub 1 sub 0. Crystalline and glassy silicates were investigated by means of sup 1 sup 7 O NMR. The dependence of the measured efg on the Si-O-AI bond angle was investigated in some crystalline aluminosilicate sodalites and kalsilite. The results show that C sub Q increases with increasing bond angle while eta decreases with increasing bond angle and they both follow a similar function to that found for the Si-O-Si ...

  16. Quaternary ammonium borohydride adsorption in mesoporous silicate MCM-48

    Energy Technology Data Exchange (ETDEWEB)

    Wolverton, Michael J [Los Alamos National Laboratory; Daemen, Luke L [Los Alamos National Laboratory; Hartl, Monika A [Los Alamos National Laboratory

    2010-01-01

    Inorganic borohydrides have a high gravimetric hydrogen density but release H2 only under energetically unfavorable conditions. Surface chemistry may help in lowering thermodynamic barriers, but inclusion of inorganic borohydrides in porous silica materials has proved hitherto difficult or impossible. We show that borohydrides with a large organic cation are readily adsorbed inside mesoporous silicates, particularly after surface treatment. Thermal analysis reveals that the decomposition thermodynamics of tetraalkylammonium borohydrides are substantially affected by inclusion in MCM-48. Inelastic neutron scattering (INS) data show that the compounds adsorb on the silica surface. Evidence of pore loading is supplemented by DSC/TGA, XRD, FTIR, and BET isotherm measurements. Mass spectrometry shows significant hydrogen release at lower temperature from adsorbed borohydrides in comparison with the bulk borohydrides. INS data measured for partially decomposed samples indicates that the decomposition of the cation and anion is likely simultaneous. Additionally, these data confirm the formation of Si-H bonds on the silica surface upon decomposition of adsorbed tetramethylammonium borohydride.

  17. Chemical interactions and configurational disorder in silicate melts

    Directory of Open Access Journals (Sweden)

    G. Ottonello

    2005-06-01

    Full Text Available The Thermodynamics of quasi-chemical and polymeric models are briefly reviewed. It is shown that the two classes are mutually consistent, and that opportune conversion of the existing quasi-chemical parameterization of binary interactions in MO-SiO2 joins to polymeric models may be afforded without substantial loss of precision. It is then shown that polymeric models are extremely useful in deciphering the structural and reactive properties of silicate melts and glasses. They not only allow the Lux-Flood character of the dissolved oxides to be established, but also discriminate subordinate strain energy contributions to the Gibbs free energy of mixing from the dominant chemical interaction terms. This discrimination means that important information on the short-, medium- and long-range periodicity of this class of substances can be retrieved from thermodynamic analysis. Lastly, it is suggested that an important step forward in deciphering the complex topology of the inhomogeneity ranges observed at high SiO2 content can be performed by applying SCMF theory and, particularly, Matsen-Schick spectral analysis, hitherto applied only to rubberlike materials.

  18. Apatite bone cement reinforced with calcium silicate fibers.

    Science.gov (United States)

    Motisuke, Mariana; Santos, Verônica R; Bazanini, Naiana C; Bertran, Celso A

    2014-10-01

    Several research efforts have been made in the attempt to reinforce calcium phosphate cements (CPCs) with polymeric and carbon fibers. Due to their low compatibility with the cement matrix, results were not satisfactory. In this context, calcium silicate fibers (CaSiO3) may be an alternative material to overcome the main drawback of reinforced CPCs since, despite of their good mechanical properties, they may interact chemically with the CPC matrix. In this work CaSiO3 fibers, with aspect ratio of 9.6, were synthesized by a reactive molten salt synthesis and used as reinforcement in apatite cement. 5 wt.% of reinforcement addition has increased the compressive strength of the CPC by 250% (from 14.5 to 50.4 MPa) without preventing the cement to set. Ca and Si release in samples containing fibers could be explained by CaSiO3 partial hydrolysis which leads to a quick increase in Ca concentration and in silica gel precipitation. The latter may be responsible for apatite precipitation in needle like form during cement setting reaction. The material developed presents potential properties to be employed in bone repair treatment.

  19. Silicate features in Galactic and extragalactic post-AGB discs

    CERN Document Server

    Gielen, C; Van Winckel, H; Evans, T Lloyd; Woods, P M; Kemper, F; Marengo, M; Meixner, M; Sloan, G C; Tielens, A G G M

    2011-01-01

    Aims. In this paper we study the Spitzer and TIMMI2 infrared spectra of post-AGB disc sources, both in the Galaxy and the LMC. Using the observed infrared spectra we determine the mineralogy and dust parameters of the discs, and look for possible differences between the Galactic and extragalactic sources. Methods. Modelling the full spectral range observed allows us to determine the dust species present in the disc and different physical parameters such as grain sizes, dust abundance ratios, and the dust and continuum temperatures. Results. We find that all the discs are dominated by emission features of crystalline and amorphous silicate dust. Only a few sample sources show features due to CO2 gas or carbonaceous molecules such as PAHs and C60 fullerenes. Our analysis shows that dust grain processing in these discs is strong, resulting in large average grain sizes and a very high crystallinity fraction. However, we do not find any correlations between the derived dust parameters and properties of the central...

  20. Leaf application of silicic acid to white oat and wheat

    Directory of Open Access Journals (Sweden)

    Rogério Peres Soratto

    2012-11-01

    Full Text Available Silicon (Si is beneficial to plants in several aspects, but there are doubts about the effectiveness of leaf application. The purpose of this work was to evaluate the effects of Si, applied in a newly developed stabilized silicic acid form to the leaf, on nutrition and yield of irrigated white oat and wheat. Two experiments were performed (one per crop in winter 2008, in Botucatu-SP, Brazil. A completely randomized block design with 14 replications was used. Treatments consisted of a control (without Si application and Si leaf spraying, at a rate of 2.0 L ha-1 of the commercial product containing 0.8 % soluble Si. Silicon rate was divided in three parts, i.e. applications at tillering, floral differentiation and booting stages. Silicon leaf application increased N, P, K, and Si concentrations in white oat flag leaf, resulting in higher shoot dry matter, number of panicles per m², number of grains per panicle and grain yield increase of 34 %. In wheat, Si leaf application increased K and Si concentrations, shoot dry matter and number of spikes per m², resulting in a grain yield increase of 26.9 %.

  1. The role of silicate surfaces on calcite precipitation kinetics

    DEFF Research Database (Denmark)

    Stockmann, Gabrielle J.; Wolff-Boenisch, Domenik; Bovet, Nicolas Emile

    2014-01-01

    The aim of this study is to illuminate how calcite precipitation depends on the identity and structure of the growth substrate. Calcite was precipitated at 25°C from supersaturated aqueous solutions in the presence of seeds of either calcite or one of six silicate materials: augite, enstatite......, labradorite, olivine, basaltic glass and peridotite rock. Calcite saturation was achieved by mixing a CaCl2-rich aqueous solution with a NaHCO3-Na2CO3 aqueous buffer in mixed-flow reactors containing 0.5-2g of mineral, rock, or glass seeds. This led to an inlet fluid calcite saturation index of 0.6 and a p......H equal to 9.1. Although the inlet fluid composition, flow rate, and temperature were identical for all experiments, the onset of calcite precipitation depended on the identity of the seeds present in the reactor. Calcite precipitated instantaneously and at a constant rate in the presence of calcite...

  2. Characterization of a silicate glass as a high dose dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Farah, K., E-mail: k.farah@cnstn.rnrt.t [Laboratoire de Radiotraitement. Centre National des Sciences et Technologie Nucleaires, 2020 Sidi-Thabet (Tunisia); Mejri, A.; Hosni, F. [Laboratoire de Radiotraitement. Centre National des Sciences et Technologie Nucleaires, 2020 Sidi-Thabet (Tunisia); Ben Ouada, H. [Laboratoire de Physique et Chimie des Interfaces, Faculte des Sciences de Monastir, 5000 Monastir (Tunisia); Fuochi, P.G.; Lavalle, M. [ISOF-CNR, Via P. Gobetti 101, 40129 Bologna (Italy); Kovacs, A. [Institute of Isotopes, HAS, P.O. Box 77, H-1525 Budapest (Hungary)

    2010-02-21

    Commercial silicate glass has been investigated as a possible high dose dosimeter using an UV-vis spectrophotometer. Glass samples were irradiated by {sup 60}Co gamma rays and the results compared with those obtained with 3.4 and 8.4 MeV electron beams. The irradiated samples showed rapid fading at room temperature immediately after irradiation. In order to improve the stability of absorbance, glass samples were submitted to post-irradiation thermal treatments (150 deg. C for 20 min). The influences of the dose, type and energy of the ionizing radiation on the fading characteristics and on the response of the irradiated and thermally treated glasses were studied. Dependence of the glass response on the temperature during gamma irradiation in the range -3 to 80 deg. C is reported. The reproducibility to reuse glass dosimeter by thermal bleaching the radiation induced colour centres at 300 deg. C for 30 min was also investigated. Calibration curves in the range 0.1-17 kGy were obtained by using in-plant calibration techniques against transfer standard alanine dosimeters in the Tunisian semi-industrial gamma irradiation facility.

  3. Optical analysis of samarium doped sodium bismuth silicate glass

    Science.gov (United States)

    Thomas, V.; Sofin, R. G. S.; Allen, M.; Thomas, H.; Biju, P. R.; Jose, G.; Unnikrishnan, N. V.

    2017-01-01

    Samarium doped sodium bismuth silicate glass was synthesized using the melt quenching method. Detailed optical spectroscopic studies of the glassy material were carried out in the UV-Vis-NIR spectral range. Using the optical absorption spectra Judd-Ofelt (JO) parameters are derived. The calculated values of the JO parameters are utilized in evaluating the various radiative parameters such as electric dipole line strengths (Sed), radiative transition probabilities (Arad), radiative lifetimes (τrad), fluorescence branching ratios (β) and the integrated absorption cross- sections (σa) for stimulated emission from various excited states of Sm3 +‡ ion. The principal fluorescence transitions are identified by recording the fluorescence spectrum. Our analysis revealed that the novel glassy system has the optimum values for the key parameters viz. spectroscopic quality factor, optical gain, stimulated emission cross section and quantum efficiency, which are required for a high performance optical amplifier. Calculated chromaticity co-ordinates (0.61, 0.38) also confirm its application potential in display devices.

  4. Preparation of calcium silicate absorbent from iron blast furnace slag.

    Science.gov (United States)

    Brodnax, L F; Rochelle, G T

    2000-09-01

    Calcium silicate hydrate (CSH) solids were prepared from hydrated lime and iron blast furnace slag in an aqueous agitated slurry at 92 degrees C. While it was hoped a minimal lime/slag ratio could be used to create near-amorphous CSH, the surface area of the product improved by increasing the lime/slag weight ratio to 2. The addition of gypsum to the lime/slag system dramatically improved the formation of surface area, creating solids with 139 m2/g after 30 hr of reaction when only a minimal amount of lime was present. The SO2 reactivity of solids prepared with gypsum greatly exceeded that of hydrated lime, achieving greater than 70-80% conversion of the alkalinity after 1 hr of reaction with SO2. The use of CaCl2 as an additive to the lime/slag system, in lieu of gypsum, also produced high-surface-area solids, 115 m2/g after 21 hr of reaction. However, the SO2 reactivity of these sorbents was relatively low given the high surface area. This emphasized that the correlation between surface area and SO2 reactivity was highly dependent on the solid phase, which was subsequently dependent on slurry composition.

  5. Combustion synthesis and photoluminescence study of silicate biomaterials

    Indian Academy of Sciences (India)

    V B Bhatkar; N V Bhatkar

    2011-10-01

    Silicate based bioceramics are promising candidates as biomaterials for tissue engineering. The combustion synthesis method provides control on the morphology and particle size of the synthesized material. This paper discusses the combustion synthesis of akermanite (Ca2MgSi2O7 and Sr2MgSi2O7), which has been shown to have good in vitro and in vivo bioactivities by earlier studies. Both Ca2MgSi2O7 and Sr2MgSi2O7 have akermanite structure. Ca2MgSi2O7 and Sr2MgSi2O7 were prepared using urea and ammonium nitrate. The combustion synthesis using urea and ammonium nitrate was found to be cost effective and efficient method of synthesis. The photoluminescence study of Ca2MgSi2O7 : Eu2+ and Sr2MgSi2O7 :Eu2+ shows host specific intense emission of Eu2+.

  6. Sintering and foaming of barium silicate glass powder compacts

    Science.gov (United States)

    Mueller, Ralf; Reinsch, Stefan; Agea-Blanco, Boris

    2016-10-01

    The manufacture of sintered glasses and glass-ceramics, glass matrix composites and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling procedures. Sintering was measured by means of heating microscopy backed up by XPD, DTA, Vacuum Hot Extraction (VHE) and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling atmosphere sig¬ni¬ficantly affected foaming. The strength of this effect increased in the order Ar ? N2 encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl.

  7. Structure characterization for the geopolymer of sodium silicate and metakaolin

    Institute of Scientific and Technical Information of China (English)

    CAO De-guang; SU Da-gen

    2005-01-01

    Geopolymers of metakaolin and sodium silicate were synthesized respectively with the ratios of the amount of SiO2 in the sodium silica solution to that of Al2O3 in metakaolinite equal to 1.0, and 0.66. The geopolymeric structures of the products were investigated by 27Al and 29Si solid-state nuclear magnetic resonances with magic-angle spinning (MAS NMR), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), differential scanning colorimetry (DSC) and scanning electron microscopy (SEM). The reaction of the Al-O sheet in meakaolinite with low-order polymerized Si-O tetrahedral units such as monomer of SiO4 yields three-dimensional structures with the Q3 Si-O tetrahedral structure and the coordination of Al(IV) in the Al-O tetrahedral structure. The geopolymers are essentially X-ray amorphous. The assays by 27Al and 29Si NMR, FTIR confirm that the active structure in the metakaolinite is the sheet of Al-O with three coordination states.

  8. Sintering and foaming of barium silicate glass powder compacts

    Directory of Open Access Journals (Sweden)

    Ralf Mueller

    2016-10-01

    Full Text Available The manufacture of sintered glasses and glass-ceramics, glass matrix composites and glass-bounded ceramics or pastes is often affected by gas bubble formation. Against this background, we studied sintering and foaming of barium silicate glass powders used as SOFC sealants using different powder milling procedures. Sintering was measured by means of heating microscopy backed up by XPD, DTA, Vacuum Hot Extraction (VHE and optical and electron microscopy. Foaming increased significantly as milling progressed. For moderately milled glass powders, subsequent storage in air could also promote foaming. Although the powder compacts were uniaxially pressed and sintered in air, the milling atmosphere sig¬ni¬ficantly affected foaming. The strength of this effect increased in the order Ar  N2 < air < CO2. Conformingly, VHE studies revealed that the pores of foamed samples predominantly encapsulated CO2, even for powders milled in Ar and N2. Results of this study thus indicate that foaming is caused by carbonaceous species trapped on the glass powder surface. Foaming could be substantially reduced by milling in water and 10 wt% HCl.

  9. Zeta potentials in the flotation of oxide and silicate minerals.

    Science.gov (United States)

    Fuerstenau, D W; Pradip

    2005-06-30

    Adsorption of collectors and modifying reagents in the flotation of oxide and silicate minerals is controlled by the electrical double layer at the mineral-water interface. In systems where the collector is physically adsorbed, flotation with anionic or cationic collectors depends on the mineral surface being charged oppositely. Adjusting the pH of the system can enhance or prevent the flotation of a mineral. Thus, the point of zero charge (PZC) of the mineral is the most important property of a mineral in such systems. The length of the hydrocarbon chain of the collector is important because of chain-chain association enhances the adsorption once the surfactant ions aggregate to form hemimicelles at the surface. Strongly chemisorbing collectors are able to induce flotation even when collector and the mineral surface are charged similarly, but raising the pH sufficiently above the PZC can repel chemisorbing collectors from the mineral surface. Zeta potentials can be used to delineate interfacial phenomena in these various systems.

  10. Changes in Global Silicate Weathering Feedbacks over Phanerozoic Time

    Science.gov (United States)

    West, A. J.

    2015-12-01

    The release of carbon from the solid Earth exerts a first-order control on the evolution of the planetary environment. This basic climate forcing is modulated by a host of chemical reactions at the Earth's surface, the pace of which are in turn regulated by tectonic forces. Together, these various pieces in the puzzle of the global carbon cycle have been identified for decades, but understanding of how they fit together has remained elusive and continues to be much debated. In particular, we now know the climate-dependence of silicate mineral weathering may vary as a function of denudation rate, which is related to tectonic drivers. This variation suggests that the strength of the weathering feedback may have varied in the past, with consequent implications for the past state of global climate. This work will survey and synthesize approaches to representing changes in the weathering feedback, showing that relatively simple parameterizations yield similar results as recently developed reactive transport approaches. This similarity gives confidence in applying the simple parameterizations to reconstructing changes in feedback strength in the geologic past, at least over Phanerozoic timescales, and allows inclusion of this effect explicitly in carbon cycle models.

  11. Silicate grout curtains behaviour for the protection of coastal aquifers

    Energy Technology Data Exchange (ETDEWEB)

    Elektorowicz, M.; Chifrina, R.; Hesnawi, R. [Concordia Univ., Montreal, Quebec (Canada)

    1997-12-31

    Tests were performed to evaluate the behaviour of silicate grout with different reagents (ethylacetate - formamide SA and calcium chloride SC) in pure silica sand and natural soils from coastal areas containing organic matter, clayey soil and silica sand. The grouted specimens were tested with simulated fresh and salt water. The setting process during chemical grouting in the soil and sand was studied. The grouting of soil and sand with SA caused a transfer to the environment of some compounds: sodium formate, sodium acetate, ammonia and part of the initial ethylacetate and formamide. This process had a tendency to decrease for approximately 4 months. The stability of specimens was low. The grouting of soil and sand with SC caused no significant contamination of the environment. The increase of pH of environmental water was even less than with SA grouting. Also, the stability of specimens is higher in comparison with SA grouting. Salt water protected the specimens grouted with SA and SC from destruction and prevented contamination.

  12. Variations in Silicate Stardust: The Perils of Averages

    Science.gov (United States)

    Williams, Kyle

    2010-01-01

    Dust plays in important role in many astrophysical environments. Here we present a study of dust emanating from Asymptotic Giant Branch (AGB) stars, which are important because they are the principle contributors of dust to interstellar space. Dust around oxygen-rich AGB stars exhibit various infrared spectral features which have been classified according to their shape and peak position and are designated as SE1 through SE8. Here we concentrate on the SE8 class which is expected to exhibit the strongest 10 micron spectral feature, attributed to silicate dust, in order to determine how much the feature varies from star to star. For each individual spectrum the dust features were isolated by dividing by a blackbody continuum. The main characteristics of the 10 and 18 micron emission features were determined, including the peak height, peak wavelength, the full width half maximum, the baricenter, and the asymmetry of the feature. The peak position of the 10 micron feature varies enormously ( 9.4.-10.4 microns). We then sought any correlations between the spectral parameters in order to determine the causes of the variations. Very few correlations were found, indicating that the causes of variations of not simply explained. Using a simple radiative transfer modeling program (DUSTY) we produced synthetic spectra in order to determine how the physical parameters of the circumstellar shell produced such varied spectra.

  13. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Palkovic, Steven D.; Moeini, Sina; Büyüköztürk, Oral, E-mail: obuyuk@mit.edu [Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Yip, Sidney [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-07-21

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.

  14. Arginine Silicate Inositol Complex Accelerates Cutaneous Wound Healing.

    Science.gov (United States)

    Durmus, Ali Said; Tuzcu, Mehmet; Ozdemir, Oguzhan; Orhan, Cemal; Sahin, Nurhan; Ozercan, Ibrahim Hanifi; Komorowski, James Richard; Ali, Shakir; Sahin, Kazim

    2016-10-14

    Arginine silicate inositol (ASI) complex is a composition of arginine, silicon, and inositol that has been shown to have beneficial effects on vascular health. This study reports the effects of an ASI ointment on wound healing in rats. A full-thickness excision wound was created by using a disposable 5 mm diameter skin punch biopsy tool. In this placebo-controlled study, the treatment group's wound areas were covered by 4 or 10 % ASI ointments twice a day for 5, 10, or 15 days. The rats were sacrificed either 5, 10, or 15 days after the wounds were created, and biopsy samples were taken for biochemical and histopathological analysis. Granulation tissue appeared significantly faster in the ASI-treated groups than in the control groups (P B cells (NF-κB), and various cytokines (TNF-α and IL-1β) measured in this study showed a significant fall in expression level in ASI-treated wounds. The results suggest that topical application of ASI ointment (especially 4 % concentration) has beneficial effects on the healing response of an excisional wound.

  15. Efficacy of dispersion of magnesium silicate (talc in papermaking

    Directory of Open Access Journals (Sweden)

    Vipul Singh Chauhan

    2017-02-01

    Full Text Available The understanding of the dispersion chemistry of papermaking grade fillers is as important as their effect on paper. Magnesium silicate (talc is one of the major fillers used for papermaking. It is hydrophobic and chemically inert. The dispersion chemistry of talc of different particle sizes was studied with wetting agent (non-ionic triblock copolymer and anionic dispersant (sodium salt of polyacrylic acid. Both wetting agent and dispersant were added in talc slurry separately and in combination. The dispersion behavior was studied through measuring the Brookfield viscosity. The wetted and dispersed talc was also added to paper to understand its effect on papermaking process and paper properties. Wetting and dispersion changed the colloidal charge chemistry of talc making it more anionic which reduced the talc retention in paper. Lowering the particle size of talc significantly improved the light scattering coefficient (LSC of paper and decreased its retention. Controlling colloidal charge of papermaking suspension with cationic polyacrylamide polymer helped in protecting the retention of talc without affecting the LSC of both filler and paper.

  16. Relationships between Basic and Silicic Magmatism in Continental Rift Settings: A Petrogeochemical Study of Carboniferous Post-collisional Rift Silicic Volcanics in Tianshan, NW China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Petrogeochemical data are reported for silicic volcanic rocks from the Tianshan Carboniferous rift, with the aim of discussing the petrogenesis of silicic magmas. Incompatible element vs. incompatible element diagrams display smooth positive trends for the Tianshan Carboniferous rift-related volcanic rocks; the isotope ratios of the silicic lavas [87Sr/86Sr(t)=0.69988-0.70532; εNd(t)=4.76-8.00; 206Pb/204Pb(t)=17.435-18.017; 207Pb/204Pb(t)=15.438-15.509; 208Pb/204Pb(t) = 37.075-37.723] encompass those of the basic lavas. These data suggest a genetic link between rhyolites and basalts, but are not definitive in establishing whether silicic rocks are related to basalts through fractional crystallization or partial melting. Geochemical modeling of incompatible vs. compatible elements excludes the possibility that silicic melts are generated by the melting of basaltic rocks, and indicates a derivation by fractional crystallization plus moderate assimilation of wall rocks (AFC) starting from intermediate rocks to silicic rocks. Continuous AFC from basalt to rhyolite,with small rates of crustal assimilation, best explains the geochemical data. The presence or absence of bimodal volcanism (the "Daly Gap") might be related to cooling rates of magma chambers. In central and eastern Tianshan, the crust was thinner and the cooling rates of the magma chamber within the crust were greater. These conditions resulted in a rapid fall in temperature within the magma reservoir and caused a narrow temperature interval over which intermediate melts formed, effectively reducing the volume of the intermediate melts.

  17. Cementing properties of steel slag activated by sodium silicates and sodium hydroxide

    Institute of Scientific and Technical Information of China (English)

    Wen Ni; En Wang; Jianping Li; Han Sun

    2005-01-01

    Steel slag which is mainly composed of γ-CasSiO4 and other silicates or alumino-silicates is activated by sodium silicates and sodium hydroxide. The powders of such steel slag are usually inert to hydrate and subsequently have very low ability of cementing. But when sodium silicates and sodium hydroxide are used as activators the steel slag shows very good properties of cementing. When activated with NaOH solution the hardened slurry of the steel slag has a compressive strength of 11.13 MPa after being cured for 28 days. When activated with Na2SiO3 solution the samples after being cured for 28 days have an average compressive strength of 40.23 MPa. While the steel slag slurry which is only mixed with water has a compressive of 0.88 MPa after being cured for 28 days.

  18. Turbulent metal-silicate mixing, fragmentation, and equilibration in magma oceans

    CERN Document Server

    Deguen, Renaud; Olson, Peter

    2014-01-01

    Much of the Earth was built by high-energy impacts of planetesimals and embryos, many of these impactors already differentiated, with metallic cores of their own. Geochemical data provide critical information on the timing of accretion and the prevailing physical conditions, but their interpretation depends critically on the degree of metal-silicate chemical equilibration during core-mantle differentiation, which is poorly constrained. Efficient equilibration requires that the large volumes of iron derived from impactor cores mix with molten silicates down to scales small enough to allow fast metal-silicate mass transfer. Here we use fluid dynamics experiments to show that large metal blobs falling in a magma ocean mix with the molten silicate through turbulent entrainment, with fragmentation into droplets eventually resulting from the entrainment process. In our experiments, fragmentation of the dense fluid occurs after falling a distance equal to 3-4 times its initial diameter, at which point a sizable volu...

  19. Geotechnical properties of two siliceous cores from the central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    Physical properties of the siliceous sediments from the Central Indian Basin are measured on two short cores. The properties such as water content, Atterberg limits, porosity specific gravity, wet density show the medium to high plastic sediment...

  20. Some observations on use of siliceous mineral waters in reduction of corrosion in RCC structures

    Digital Repository Service at National Institute of Oceanography (India)

    Venugopal, C.

    The corrosion-resisting characteristics of reinforcement in cement blended with siliceous mineral wastes viz. gold tailing and flyash have been evaluated by using an accelerated corrosion technique. The additions of these mineral admixtures...

  1. Observations on the morphological diversity and distribution of two siliceous nannoplankton genera, Hyalolithus and Petasaria

    DEFF Research Database (Denmark)

    Jordan, Richard W.; Abe, Kent; Cruz, Jarret

    2016-01-01

    Scale-bearing siliceous nannoplankton are occasionally encountered in surface seawater samples, but are rarely identified or illustrated. In this study, the morphological diversity of the haptophyte Hyalolithus neolepis and the enigmatic Petasaria heterolepis are investigated in scanning and tran...

  2. Himalayan sedimentary pulses recorded by silicate detritus within a ferromanganese crust from the Central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Banakar, V.K.; Galy, A.; Sukumaran, N.P.; Parthiban, G.; Volvaiker, A.Y.

    A Central Indian Ocean deep-water seamount hydrogenous ferromanganese crust (SS663-Crust) contains variable (7-23%) amounts of detrital material (silicate-detritus). Taking into account the growth rate of the authigenic component, the accumulation...

  3. Elastic and anelastic anomalies in (Ca,Sr)TiO perovskites: Analogue behaviour for silicate perovskites

    OpenAIRE

    Walsh, J.W.; Taylor, P.A.; Buckley, A.; Darling, T.W.; Schreuer, J.; Carpenter, M.A.

    2008-01-01

    Elastic and anelastic anomalies in (Ca,Sr)TiO3 perovskites: Analogue behaviour for silicate perovskites UNITED KINGDOM (Walsh, J.W.) UNITED KINGDOM Received: 2007-10-30 Revised: 2008-02-18 Accepted: 2008-02-27

  4. Characterization of Electrochemical and Morphological Properties of Iron-Phosphate-Silicate Chemical Garden Structures

    Science.gov (United States)

    Doloboff, I. J.; Barge, L. M.; Russell, M. J.; Kanik, I.

    2012-03-01

    Examination of the growth of Fe^2^+, phosphate, and silicate chemical garden structures to understand properties of similar structures that may have formed at Hadean alkaline hydrothermal vents which may play an important role in the emergence of life.

  5. Polymer Derived Yttrium Silicate Ablative TPS Materials for Next-Generation Exploration Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Through the proposed NASA SBIR program, NanoSonic will optimize its HybridSil® derived yttrium silicates to serve as next-generation reinforcement for carbon...

  6. Polymer Derived Rare Earth Silicate Nanocomposite Protective Coatings for Nuclear Thermal Propulsion Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I SBIR program is to develop polymer derived rare earth silicate nanocomposite environmental barrier coatings (EBC) for providing...

  7. Polymer Derived Rare Earth Silicate Nanocomposite Protective Coatings for Nuclear Thermal Propulsion Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Leveraging a rapidly evolving state-of-the-art technical base empowered by Phase I NASA SBIR funding, NanoSonic's polymer derived rare earth silicate EBCs will...

  8. [Analysis of tartrazine aluminum lake and sunset yellow aluminum lake in foods by capillary zone electrophoresis].

    Science.gov (United States)

    Zhang, Yiding; Chang, Cuilan; Guo, Qilei; Cao, Hong; Bai, Yu; Liu, Huwei

    2014-04-01

    A novel analytical method for tartrazine aluminum lake and sunset yellow aluminum lake using capillary zone electrophoresis (CZE) was studied. The pigments contained in the color lakes were successfully separated from the aluminum matrix in the pre-treatment process, which included the following steps: dissolve the color lakes in 0.1 mol/L H2SO4, adjust the pH of the solution to 5.0, then mix it with the solution of EDTA x 2Na and heat it in a water bath, then use polyamide powder as the stationary phase of solid phase extraction to separate the pigments from the solution, and finally elute the pigments with 0.1 mol/L NaOH. The CZE conditions systematically optimized for tartrazine aluminum lake were: 48.50 cm of a fused silica capillary with 40.00 cm effective length and 50 microm i. d., the temperature controlled at 20.0 degrees C, 29.0 kV applied, HPO4(2-)-PO4(3-) (0.015 mol/L, pH 11.45) solution as running buffer, detection at 263 nm. The conditions for sunset yellow aluminum lake were: the same capillary and temperature, 25.0 kV applied, HPO4(2-)-PO4(3-) (0.025 mol/L, pH 11.45) solution as running buffer, detection at 240 nm. The limits of detection were 0.26 mg/L and 0.27 mg/L, and the linear ranges were 0.53-1.3 x 10(2) mg/L and 0.54-1.4 x 10(2) mg/L for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. The RSDs were 4.3% and 5.7% (run to run, n = 6), 5.6% and 6.0% (day to day, n = 6) for tartrazine aluminum lake and sunset yellow aluminum lake, respectively. Further developments for this method could make it a routinely used method analyzing color lakes in foods.

  9. Aluminum nanocomposites for elevated temperature applications

    Science.gov (United States)

    Borgonovo, C.; Apelian, D.; Makhlouf, M. M.

    2011-02-01

    Aluminum casting alloys conventionally used in the automotive and aerospace industries (i.e., Al-Zn-Mg, and Al-Cu-Mg systems) are able to achieve excellent tensile strength at room temperature. At high temperatures, such alloys lose dimensional stability and their mechanical properties rapidly degrade. Aluminum-based nanocomposites show the potential for enhanced performance at high temperatures. The manufacturing process, however, is difficult; a viable and effective method for large-scale applications has not been developed. In the current study, an innovative and cost-effective approach has been adopted to manufacture Al/AlN composites. A nitrogen-bearing gas is injected into the melt and AlN particles synthesize in-situ via chemical reaction. In a preliminary stage, a model able to predict the amount of reinforcement formed has been developed. AlN dispersoids have been succesfully synthesized in the matrix and the model has been experimentally validated.

  10. Generation and structural characterization of aluminum cyanoacetylide

    Energy Technology Data Exchange (ETDEWEB)

    Cabezas, Carlos; Peña, Isabel; Alonso, José L., E-mail: alargo@qf.uva.es, E-mail: jlalonso@qf.uva.es [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopia y Bioespectroscopia, Unidad Asociada CSIC, Parque Científico Uva, Universidad de Valladolid, Paseo de Belén 5, 47011 Valladolid (Spain); Barrientos, Carmen; Largo, Antonio, E-mail: alargo@qf.uva.es, E-mail: jlalonso@qf.uva.es [Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, Campus Miguel Delibes, Paseo de Belén 7, 47011 Valladolid (Spain); Guillemin, Jean-Claude [Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7 (France); Cernicharo, José [Group of Molecular Astrophysics, ICMM C/Sor Juana Ines de la Cruz N3 Cantoblanco, 28049 Madrid (Spain)

    2014-09-14

    Combined spectroscopy measurements and theoretical calculations bring to light a first investigation of a metallic cyanoacetylide, AlC{sub 3}N, using laser ablation molecular beam Fourier transform microwave spectroscopy. This molecule was synthesized in a supersonic expansion by the reaction of aluminum vapour with C{sub 3}N, produced from solid aluminum rods and BrCCCN in a newly constructed ablation-heating nozzle device. A set of accurate rotational and {sup 27}Al and {sup 14}N nuclear quadrupole coupling constants have been determined from the analysis of the rotational spectrum and compared with those predicted in a high-level ab initio study, conducting to the assignment of the observed species to linear AlCCCN. We have searched for this species towards the carbon-rich evolved star IRC + 10216 but only an upper limit to its abundance has been obtained.

  11. Generation and structural characterization of aluminum cyanoacetylide

    Science.gov (United States)

    Cabezas, Carlos; Barrientos, Carmen; Largo, Antonio; Guillemin, Jean-Claude; Cernicharo, José; Peña, Isabel; Alonso, José L.

    2015-01-01

    Combined spectroscopy measurements and theoretical calculations bring to light a first investigation of a metallic cyanoacetylide, AlC3N, using laser ablation molecular beam Fourier transform microwave spectroscopy. This molecule was synthesized in a supersonic expansion by the reaction of aluminum vapour with C3N, produced from solid aluminum rods and BrCCCN in a newly constructed ablation-heating nozzle device. A set of accurate rotational and 27Al and 14N nuclear quadrupole coupling constants have been determined from the analysis of the rotational spectrum and compared with those predicted in a high-level ab initio study, conducting to the assignment of the observed species to linear AlCCCN. We have searched for this species towards the carbon-rich evolved star IRC + 10216 but only an upper limit to its abundance has been obtained. PMID:25217914

  12. Fluorescence energy transfer enhancement in aluminum nanoapertures

    CERN Document Server

    de Torres, Juan; Moparthi, Satish Babu; Grigoriev, Victor; Wenger, Jérome

    2015-01-01

    Zero-mode waveguides (ZMWs) are confining light into attoliter volumes, enabling single molecule fluorescence experiments at physiological micromolar concentrations. Among the fluorescence spectroscopy techniques that can be enhanced by ZMWs, F\\"{o}rster resonance energy transfer (FRET) is one of the most widely used in life sciences. Combining zero-mode waveguides with FRET provides new opportunities to investigate biochemical structures or follow interaction dynamics at micromolar concentration with single molecule resolution. However, prior to any quantitative FRET analysis on biological samples, it is crucial to establish first the influence of the ZMW on the FRET process. Here, we quantify the FRET rates and efficiencies between individual donor-acceptor fluorophore pairs diffusing in aluminum zero-mode waveguides. Aluminum ZMWs are important structures thanks to their commercial availability and the large literature describing their use for single molecule fluorescence spectroscopy. We also compare the ...

  13. Etching Behavior of Aluminum Alloy Extrusions

    Science.gov (United States)

    Zhu, Hanliang

    2014-11-01

    The etching treatment is an important process step in influencing the surface quality of anodized aluminum alloy extrusions. The aim of etching is to produce a homogeneously matte surface. However, in the etching process, further surface imperfections can be generated on the extrusion surface due to uneven materials loss from different microstructural components. These surface imperfections formed prior to anodizing can significantly influence the surface quality of the final anodized extrusion products. In this article, various factors that influence the materials loss during alkaline etching of aluminum alloy extrusions are investigated. The influencing variables considered include etching process parameters, Fe-rich particles, Mg-Si precipitates, and extrusion profiles. This study provides a basis for improving the surface quality in industrial extrusion products by optimizing various process parameters.

  14. Generation and structural characterization of aluminum cyanoacetylide

    Science.gov (United States)

    Cabezas, Carlos; Barrientos, Carmen; Largo, Antonio; Guillemin, Jean-Claude; Cernicharo, José; Peña, Isabel; Alonso, José L.

    2014-09-01

    Combined spectroscopy measurements and theoretical calculations bring to light a first investigation of a metallic cyanoacetylide, AlC3N, using laser ablation molecular beam Fourier transform microwave spectroscopy. This molecule was synthesized in a supersonic expansion by the reaction of aluminum vapour with C3N, produced from solid aluminum rods and BrCCCN in a newly constructed ablation-heating nozzle device. A set of accurate rotational and 27Al and 14N nuclear quadrupole coupling constants have been determined from the analysis of the rotational spectrum and compared with those predicted in a high-level ab initio study, conducting to the assignment of the observed species to linear AlCCCN. We have searched for this species towards the carbon-rich evolved star IRC + 10216 but only an upper limit to its abundance has been obtained.

  15. Aluminum matrix composites reinforced with alumina nanoparticles

    CERN Document Server

    Casati, Riccardo

    2016-01-01

    This book describes the latest efforts to develop aluminum nanocomposites with enhanced damping and mechanical properties and good workability. The nanocomposites exhibited high strength, improved damping behavior and good ductility, making them suitable for use as wires. Since the production of metal matrix nanocomposites by conventional melting processes is considered extremely problematic (because of the poor wettability of the nanoparticles), different powder metallurgy routes were investigated, including high-energy ball milling and unconventional compaction methods. Special attention was paid to the structural characterization at the micro- and nanoscale, as uniform nanoparticle dispersion in metal matrix is of prime importance. The aluminum nanocomposites displayed an ultrafine microstructure reinforced with alumina nanoparticles produced in situ or added ex situ. The physical, mechanical and functional characteristics of the materials produced were evaluated using different mechanical tests and micros...

  16. The formation of nuggets of highly siderophile elements in quenched silicate melts at high temperatures: Before or during the silicate quench?

    Science.gov (United States)

    Malavergne, V.; Charon, E.; Jones, J.; Cordier, P.; Righter, K.; Deldicque, D.; Hennet, L.

    2016-01-01

    The Highly Siderophile Elements (HSE) are powerful tracers of planetary differentiation. Despite the importance of their partitioning between silicate and metal for the understanding of planetary core formation, especially for the Earth and Mars, there is still a huge discrepancy between conclusions based on different high temperature (HT) experimental studies. These disagreements may be due to the presence of HSE micro and nanonuggets in HT experiments. The formation of these nuggets is still interpreted in different ways. One hypothesis is that these HSE nuggets formed during the quench of the silicate melt, while another hypothesis supposes that these nuggets formed before the quench and represented artefacts of HT experiments. The goal of this work is to clarify whether the presence of HSE nuggets in silicate melts is linked to a quench effect or not. Understanding the formation of these HSE nuggets represents thus a necessary step towards the resolution of the Earth's core formation scenarios. We performed new HT experiments (1275-2000 °C) at different oxygen fugacities (fO2), between ambient air up to ∼5 log units below the Iron-Wüstite buffer [IW-5], for two different silicate compositions (synthetic martian and terrestrial basalts) mixed with a metallic mixture of Pt-Au-Pd-Ru. Our 1275-1600 °C experiments were contained in either olivine, diopside or graphite crucible; experiments at 2000 °C were performed using a levitation method, so no capsule was necessary. Our samples contained quenched silicate melts, minerals (olivine, pyroxene, spinel depending on the run), a two-phase metallic bead and nano and micro-nuggets of HSE. Our samples underwent fine textural, structural and analytical characterizations. The distribution of the nuggets was not homogeneous throughout the quenched silicate melt. HSE nuggets were present within crystals. Dendritic textures from the quenched silicate melt formed around HSE nuggets, which could be crystallized, showing

  17. Novel routes to metalloorganics containing aluminum from minerals

    Science.gov (United States)

    Narayanan, Ramasubramanian

    Novel pathways for synthesizing Al metalloorganics directly from widely available oxides and oxo-hydroxides of aluminum are developed. The Al metalloorganics are then used to produce low-cost precursors for ceramics and polymers containing Al. Alumatrane, an unique, air-stable, aluminum alkoxide is prepared in one step from aluminum hydroxide in quantitative yields. Subsequently, alumatrane was used to prepare and characterize all group II dialuminate ceramics (MAlsb2Osb4, M = Mg, Ca, Sr, Ba). Similarly, an air-stable alkoxide of silicon was synthesized directly from SiOsb2, and is used in conjunction with alumatrane to produce precursors for aluminosilicate ceramics (MAlSiOsb4, M = K, Li, Na). Aluminum formate is synthesized, in differing efficiencies, from different crystalline minerals of Al, by direct dissolution in formic acid. A few other aluminum carboxylates are also synthesized, either directly from minerals or from aluminum formates, thus expanding the scope of the acid dissolution of aluminum hydroxides. Aluminum allyloxypropanoate (AAP) (Al(Osb2CCHsb2CHsb2OCH{=}CHsb2)sb2(OH)), an aluminum carboxylate with a polymerizable group has been synthesized from aluminum formate. This, has been incorporated into methyl methacrylate (MMA) polymers to impart fire retardancy. The increase in char yields as a result of AAP incorporation, indicate improved fire retardancy. Fire retardant characteristics of alumatrane has also been investigated, in MMA polymers and in a polyurethane polymer, taking char yields as a measure of fire retardance efficiency.

  18. A Positron Annihilation Study of Corrosion of Aluminum and Aluminum Alloy by NaOH

    Science.gov (United States)

    Wu, Y. C.; Zhai, T.; Coleman, P. G.

    2012-08-01

    Corrosion of fully-annealed pure aluminum and a continuous-cast AA2037 aluminum alloy (solutionized and water quenched) in a 1M NaOH solution for various periods of time were analyzed with positron beam-based Doppler broadening spectroscopy. By varying the energy of the incident positron beam, corrosion-induced defects at different depths from the surface were detected. It was found that the Doppler-broadened annihilation line-width parameter was significantly increased near the surface of pure aluminum after corrosion, probably due to the interaction between positrons and nanometer-sized voids formed near the aluminum surface during corrosion. Examination by atomic force microscopy indicated that many pits were formed on the aluminum surface after corrosion. In contrast, a significant decrease in the line-width parameter was observed in AA2037 alloy after corrosion and interpreted as being caused by copper enrichment at the metal-oxide interface during corrosion; such enrichment at large cavity sites was confirmed by energy dispersion spectrometry.

  19. Corrosion inhibition mechanisms of aluminum alloy 2024-T3 by selected non-chromate inhibitors

    Science.gov (United States)

    Lopez-Garrity, Omar A.

    The pursuit to find a chromate-alternative has led to the development of several chromate-free aerospace primers and coating systems that offer good protection. However, fundamental understanding of the functionality of the chromate-free pigments that are embedded within these coating systems is lacking. The objective of this study was to understand the fundamental mechanism of corrosion inhibition of aluminum alloy 2024-T3 by molybdate (MoO 42-), silicate (SiO32-), and praseodymium (Pr3+) with the goal of developing the kind of understanding that was accomplished for chromate. Furthermore, since most inhibiting conversion coatings and pigments act by releasing soluble species into the local environment, it was of interest to understand the mechanism of inhibition in aqueous 0.1 M NaCl solution. The mechanism of inhibition of AA2024-T3 by the select non-chromate inhibitors was investigated using various electrochemical, microscopic and spectroscopic techniques. Naturally aerated polarization curves showed that molybdate provided mixed inhibition in near-neutral pH and at a threshold concentration of 0.1 M. The largest effect was a 250 mV increase in the breakdown potential associated with pitting and a 350 mV decrease in the open-circuit potential (OCP). In addition, electrochemical impedance indicated that the corrosion inhibition mechanism is oxygen-dependent owing to the protection afforded by Mo(VI) species. It was proposed that the corrosion inhibition of AA2024-T3 by molybdate may occur following a two-step process whereby molybdate is rapidly reduced to MoO.(OH)2 over the intermetallic particles and is subsequently oxidized to intermediate molybdenum oxides (e.g. Mo4O11) in the presence of oxygen which is reduced. This in turn may lead to a local acidification, promoting the condensation and polymerization of molybdate species in solution to form polymolybdate species (Mo7O24 6- and Mo8O264-). Furthermore, S-phase particle dissolution is decreased

  20. Aluminum alloy nanosecond vs femtosecond laser marking

    Indian Academy of Sciences (India)

    S Rusu; A Buzaianu; D G Galusca; L Ionel; D Ursescu

    2013-11-01

    Based on the lack of consistent literature publications that analyse the effects of laser marking for traceability on various materials, the present paper proposes a study of the influence of such radiation processing on an aluminum alloy, a vastly used material base within several industry fields. For the novelty impact, femtolaser marking has been carried out, besides the standard commercial nanosecond engraving. All the marks have been analysed using profilometry, overhead and cross-section SEM microscopy, respectively and EDAX measurements.

  1. Testing conformal mapping with kitchen aluminum foil

    CERN Document Server

    Haas, S; Crivelli, P

    2016-01-01

    We report an experimental verification of conformal mapping with kitchen aluminum foil. This experiment can be reproduced in any laboratory by undergraduate students and it is therefore an ideal experiment to introduce the concept of conformal mapping. The original problem was the distribution of the electric potential in a very long plate. The correct theoretical prediction was recently derived by A. Czarnecki (Can. J. Phys. 92, 1297 (2014)).

  2. Spin Forming of Aluminum Metal Matrix Composites

    Science.gov (United States)

    Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    An exploratory effort between NASA-Marshall Space Flight Center (MSFC) and SpinCraft, Inc., to experimentally spin form cylinders and concentric parts from small and thin sheets of aluminum Metal Matrix Composites (MMC), successfully yielded good microstructure data and forming parameters. MSFC and SpinCraft will collaborate on the recent technical findings and develop strategy to implement this technology for NASA's advanced propulsion and airframe applications such as pressure bulkheads, combustion liner assemblies, propellant tank domes, and nose cone assemblies.

  3. Why Electrolytic Aluminum Overcapacity Lingering for Years

    Institute of Scientific and Technical Information of China (English)

    Yan Manman

    2009-01-01

    @@ According to the Opinions on Restraining Overcapacity and Redundant Construction in Parts of Industries and Leading the Healthy Development of Industries" (Hereafter short for OPINIONS) promulgated by ten ministries and emphasized by the State Council,the electrolytic aluminum capacity in China is 18 million tons,accounting for 42.9% of the global capacity,and the capacity utility rate is only 73.2%.

  4. Composite hydrophilic coating for conditioner aluminum fins

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    To solve the so-called "white rust" and 'water bridge" problems of the aluminum fins for heat exchanger of automobile air conditioner, aimed at nationalizing the art of hydrophilic coating technology, the choice of coating forming and curing materials was investigated. By measuring the water contact angle, SEM surface scanning and ingredients analysis of the coating, optimal parameters and composition are acquired. The coating forming mechanisms of the composition was also expatiated. The coating obtained has good hydrophilic and other properties.

  5. Anodizing And Sealing Aluminum In Nonchromated Solutions

    Science.gov (United States)

    Emmons, John R.; Kallenborn, Kelli J.

    1995-01-01

    Improved process for anodizing and sealing aluminum involves use of 5 volume percent sulfuric acid in water as anodizing solution, and 1.5 to 2.0 volume percent nickel acetate in water as sealing solution. Replaces process in which sulfuric acid used at concentrations of 10 to 20 percent. Improved process yields thinner coats offering resistance to corrosion, fatigue life, and alloy-to-alloy consistency equal to or superior to those of anodized coats produced with chromated solutions.

  6. Electrochemical Studies in Aluminum Chloride Melts

    Science.gov (United States)

    1976-07-31

    Molten Salt Systems", Symposium on Molten Salts, Symposium Volume, The Electrochemical Society , in press (1976). Manuscripts in Preparation--Related to...Fused Salt Technology, Electrochemical Society Meeting, Chicaao, May 8-13, 1973. R. A. Osteryoung, R. H. Abel, L. G. Boxall and B. H. Vassos, "An...aluminate Melts", Electrochemical Society , San Francisco, CA, May, 1974. R. A. Osteryoung, "Chemistry in Aluminum Chloride Melts", Fifth International

  7. Preparation and characterization of aluminum stearate

    Directory of Open Access Journals (Sweden)

    Lončar Eva S.

    2003-01-01

    Full Text Available Preparation of aluminum stearate by the precipitation method was examined under various conditions of stearic acid saponification with sodium hydroxide. It was proved that the most favorable ratio of acid/alkali was 1:1.5 and that the obtained soap was very similar to the commercial product. Endothermic effects determined by differential scanning calorimetry and also the other parameters showed that the soaps consisted mono-, di-, tristearates and non-reacted substances, where distearate was the dominant form.

  8. Magnesium Aluminum Borides as Explosive Materials

    Science.gov (United States)

    2011-12-20

    Figure 1). Hsia argued that compounds that do not undergo decomposition reactions are better choices for rocket propellants since the endothermic ...decomposition reaction is undesired. The endotherm for AlB2 decomposition, however, is small[13], especially when compared to the heat of combustion... exotherms for the boron carbide materials are comparable to those of Al + 2B and AlB2. 40 Figure 23. TGA of silicon borides vs . aluminum borides

  9. Synthesis and Characterization of High Aluminum Zeolite X from Technical Grade Materials

    Directory of Open Access Journals (Sweden)

    Seyed Kamal Masoudian

    2013-06-01

    Full Text Available Zeolites are widely used as ion exchangers, adsorbents, separation materials and catalyst due to their well-tailored and highly-reproducible structures; therefore, the synthesis of zeolite from low grade resources can be interested. In the present work, high aluminum zeolite X was prepared from mixing technical grade sodium aluminate and sodium silicate solutions at temperatures between 70°C and 100°C. The synthesized zeolite X was characterized by SEM and X-ray methods according to ASTM standard procedures. The results showed that aging of the synthesis medium at the room temperature considerably increased the selectivity of zeolite X formation. On the other hand, high temperature of reaction mixture during crystallization formed zeolite A in the product; therefore, it decreased the purity of zeolite X. In addition, it was found that increasing H2O/Na2O and decreasing Na2O/SiO2 molar ratios in the reaction mixture resulted product with higher purity. © 2013 BCREC UNDIP. All rights reservedReceived: 7th January 2013; Revised: 7th April 2013; Accepted: 19th April 2013[How to Cite: Masoudian, S. K., Sadighi, S., Abbasi, A. (2013. Synthesis and Characterization of High Alu-minum Zeolite X from Technical Grade Materials. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 54-60. (doi:10.9767/bcrec.8.1.4321.54-60][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4321.54-60] | View in  |

  10. STUDY ON CORROSION RESISTANCE OF REBAR IN HYBRID GRINDING FLY ASH-LIME SILICATE CONCRETE

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The corrosion resistance of rebar in fly ash-lime sili cate concrete as well as its marco properties and pore distribution is investiga ted.The results show that the fly ash is activated, the compressive strength of the silicate concrete is strengthened and its pore structure is modified after f ly ash and lime being hybrid ground.Also the corrosion resistance of rebar in the silicate concrete is improved.

  11. A MODEL FOR THE DUST ENVELOPE OF THE SILICATE CARBON STAR IRAS 09425-6040

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kyung-Won, E-mail: kwsuh@chungbuk.ac.kr [Department of Astronomy and Space Science, Chungbuk National University, Cheongju-City, 28644 (Korea, Republic of)

    2016-03-01

    IRAS 09425-6040 (I09425) is a silicate carbon star with conspicuous crystalline silicate and water-ice features and emission excesses in the far-infrared and millimeter (mm) wavelength ranges. To understand properties of the dust envelope of I09425, we propose a physical model based on the observations and known properties of asymptotic giant branch stars and dust. We perform radiative transfer model calculations using multiple dust shells and disks with various dust species. We compare the model results with the observed spectral energy distribution (SED) acquired with different telescopes. We find that the physical model for I09425 using multiple shells of carbon and silicate dust and multiple disks of amorphous and crystalline silicates reproduces the observed SED fairly well. This object looks to have detached cold O-rich (silicate and water-ice) dust shells, which could be remnants of the recent chemical transition from O to C and an inner C-rich dust shell. A long-lived thin disk of very large silicate grains can reproduce the emission excess in the mm wavelength band and a recently formed thick disk of crystalline silicates can reproduce the prominent emission features in the spectral range 8–45 μm. The highly crystallized silicates could be recently formed by high temperature annealing due to the last O-rich superwind just before the chemical transition of the central star. I09425 could be a rare object that has the remnants of past O-rich stellar winds in the outer shells as well as in the circumbinary disks.

  12. Pilot scale direct flotation of a phosphate ore with silicate-carbonate gangue.

    OpenAIRE

    2012-01-01

    The present pilot scale study addresses the direct flotation route for the concentration of a phosphate ore bearing a silicate-carbonate gangue. The target was to selectively separate apatite from a phosphate ore bearing silicate/carbonate gangue using flotation columns. Based on the results of a previous laboratory scale investigation, a reagents scheme was selected and tested, using, under alkaline conditions, corn starch and a natural collector extracted from the distillation of coconut oi...

  13. Radiation Shielding Properties Comparison of Pb-Based Silicate, Borate, and Phosphate Glass Matrices

    OpenAIRE

    Suwimon Ruengsri

    2014-01-01

    Theoretical calculations of mass attenuation coefficients, partial interactions, atomic cross-section, and effective atomic numbers of PbO-based silicate, borate, and phosphate glass systems have been investigated at 662 keV. PbO-based silicate glass has been found with the highest total mass attenuation coefficient and then phosphate and borate glasses, respectively. Compton scattering has been the dominate interaction contributed to the different total attenuation coefficients in each of th...

  14. Synthesis and optical features of an europium organic-inorganic silicate hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Franville, A.C.; Zambon, D.; Mahiou, R.; Chou, S.; Cousseins, J.C. [Universite Blaise Pascal, Aubiere (France). Lab. des Materiaux Inorganiques; Troin, Y. [Laboratoire de Chimie des Heterocycles et des Glucides, EA 987, Universite Blaise-Pascal and ENSCCF, F-63177 Aubiere Cedex (France)

    1998-07-24

    A europium organic-inorganic silicate hybrid was synthesized by grafting a coordinative group (dipicolinic acid) to a silicate network precursor (3-aminopropyltriethoxysilane) via a covalent bonding. Sol-gel process and complexation were performed using different experimental conditions. The hybrid materials, in particular the Eu{sup 3+} coordination mode, were characterized by infrared and luminescence spectroscopies. Morphology of the materials and TG analysis showed that grafted silica enhanced thermal and mechanical resistances of the organic part. (orig.) 7 refs.

  15. Fatigue performance of welded aluminum deck structures

    Energy Technology Data Exchange (ETDEWEB)

    Haagensen, P.J.; Ranes, M.; Kluken, A.O.; Kvale, I.

    1996-12-01

    Aluminum alloys are used increasingly in load carrying structures where low weight and low maintenance costs are at a premium. Helicopter decks, structures for living quarters and personnel transfer bridges between platforms are examples of offshore applications. While these structures are not usually subjected to high fatigue loads, the increasing use of aluminum in high speed ships, and more recently in highway bridge structures, makes the question of fatigue performance more important. In this paper the fatigue properties of small scale weldments in an AA6005 alloy are compared with the results of fatigue tests on full scale sections of welded extrusions in the same material, which were used in an aluminum bridge deck structure. The fatigue performance is also compared with the fatigue clauses in the new British design code BS8118 for aluminium structures and the proposed Eurocode 9. The prospects of using a new joining technique, friction stir welding (FSW), in the production of large scale panels for deck and ship hull structures is discussed. The FSW process is described briefly, and some fatigue test data are presented.

  16. Chromic acid anodizing of aluminum foil

    Science.gov (United States)

    Dursch, H.

    1988-01-01

    The success of the Space Station graphite/epoxy truss structure depends on its ability to endure long-term exposure to the LEO environment, primarily the effects of atomic oxygen and the temperture cycling resulting from the 94 minute orbit. This report describes the development and evaluation of chromic acid anodized (CAA) aluminum foil as protective coatings for these composite tubes. Included are: development of solar absorptance and thermal emittance properties required of Al foil and development of CAA parameters to achieve these optical properties; developing techniques to CAA 25 ft lengths of Al foil; developing bonding processes for wrapping the Al foil to graphite/epoxy tubes; and atomic oxygen testing of the CAA Al foil. Two specifications were developed and are included in the report: Chromic Acid Anodizing of Aluminum Foil Process Specification and Bonding of Anodized Aluminum Foil to Graphite/Epoxy Tubes. Results show that CAA Al foil provides and excellent protective and thermal control coating for the Space Station truss structure.

  17. Trends in the adsorption and reactivity of hydrogen on magnesium silicate nanoclusters.

    Science.gov (United States)

    Oueslati, Ichraf; Kerkeni, Boutheïna; Bromley, Stefan T

    2015-04-14

    We study nanoclusters of Mg-rich olivine and pyroxene (having (MgO)6(SiO2)3 and (MgO)4(SiO2)4 compositions) with respect to their reactivity towards hydrogen atoms, using density functional calculations. Ultrasmall silicate particles are fundamental intermediates in cosmic dust grain formation and processing, and are thought to make up a significant mass fraction of the grain population. Due to their nanoscale dimensions and high surface area to bulk ratios, they are likely to also have a disproportionately large influence on surface chemistry in the interstellar medium. This work investigates the potential role of silicate nanoclusters in vital interstellar hydrogen-based chemistry by studying atomic H adsorption and H2 formation. Our extensive set of calculations confirm the generality of a Brønsted-Evans-Polanyi (BEP) relation between the H2 reaction barrier and the 2Hchem binding energy, suggesting it to be independent of silicate dust grain shape, size, crystallinity and composition. Our results also suggest that amorphous/porous grains with forsteritic composition would tend to dissociate H2, but relatively Mg-poor silicate grains (e.g. enstatite composition) and/or more crystalline/compact silicate grains would tend to catalyse H2 formation. The high structural thermostability of silicate nanoclusters with respect to the heat released during exothermic H2 formation reactions is also verified.

  18. Determining the Metal/Silicate Partition Coefficient of Germanium: Implications for Core and Mantle Differentiation.

    Science.gov (United States)

    King, C.; Righter, K.; Danielson, L.; Pando, K.; Lee, C.

    2010-01-01

    Currently there are several hypotheses for the thermal state of the early Earth. Some hypothesize a shallow magma ocean, or deep magma ocean, or heterogeneous accretion which requires no magma ocean at all. Previous models are unable to account for Ge depletion in Earth's mantle relative to CI chondrites. In this study, the element Ge is used to observe the way siderophile elements partition into the metallic core. The purpose of this research is to provide new data for Ge and to further test these models for Earth's early stages. The partition coefficients (D(sub Ge) = c(sub metal)/c(sub silicate), where D = partition coefficient of Ge and c = concentration of Ge in the metal and silicate, respectively) of siderophile elements were studied by performing series of high pressure, high temperature experiments. They are also dependent on oxygen fugacity, and metal and silicate composition. Ge is a moderately siderophile element found in both the mantle and core, and has yet to be studied systematically at high temperatures. Moreover, previous work has been limited by the low solubility of Ge in silicate melts (less than 100 ppm and close to detection limits for electron microprobe analysis). Reported here are results from 14 experiments studying the partitioning of Ge between silicate and metallic liquids. The Ge concentrations were then analyzed using Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) which is sensitive enough to detect ppm levels of Ge in the silicate melt.

  19. Hydration characteristics and environmental friendly performance of a cementitious material composed of calcium silicate slag.

    Science.gov (United States)

    Zhang, Na; Li, Hongxu; Zhao, Yazhao; Liu, Xiaoming

    2016-04-05

    Calcium silicate slag is an alkali leaching waste generated during the process of extracting Al2O3 from high-alumina fly ash. In this research, a cementitious material composed of calcium silicate slag was developed, and its mechanical and physical properties, hydration characteristics and environmental friendly performance were investigated. The results show that an optimal design for the cementitious material composed of calcium silicate slag was determined by the specimen CFSC7 containing 30% calcium silicate slag, 5% high-alumina fly ash, 24% blast furnace slag, 35% clinker and 6% FGD gypsum. This blended system yields excellent physical and mechanical properties, confirming the usefulness of CFSC7. The hydration products of CFSC7 are mostly amorphous C-A-S-H gel, rod-like ettringite and hexagonal-sheet Ca(OH)2 with small amount of zeolite-like minerals such as CaAl2Si2O8·4H2O and Na2Al2Si2O8·H2O. As the predominant hydration products, rod-like ettringite and amorphous C-A-S-H gel play a positive role in promoting densification of the paste structure, resulting in strength development of CFSC7 in the early hydration process. The leaching toxicity and radioactivity tests results indicate that the developed cementitious material composed of calcium silicate slag is environmentally acceptable. This study points out a promising direction for the proper utilization of calcium silicate slag in large quantities.

  20. Carbonate verse silicate Sr isotope in lake sediments and its response to Little Ice Age

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The 87Sr/86Sr ratios of silicate (acid-insoluble, AI) and carbonate (acid-soluble, AS) of the lake sediments from the Daihai Lake, Inner Mongolia, since the last 500 years are measured respectively, indicating that chemical weathering of silicate minerals was in an early stage since the Little Ice Age within the Daihai watershed by combination with mineral constitute, Rb/Sr ratio and CaCO3 content in the sediments. During the Little Ice Age maximum, an evident peak in the 87Sr/86Sr ratios of both silicate and carbonate in sediments suggests that a cold climate condition is unfavorable to dissolving radiogenic strontium from silicate minerals. Meanwhile, the variation of 87Sr/86Sr ratios of silicate and carbonate also reflects a projected warming climate favorable to intensifying chemical weathering after the Little Ice Age. Consequently, the 87Sr/86Sr ratio of both silicate and carbonate in inland lake sediments can be used as an effective proxy of the past climate in single watershed.