Sample records for vermicompost frente al

  1. ENGINEERING ASSESSMENT OF VERMICOMPOSTING MUNICIPAL WASTEWATER SLUDGES

    EPA Science Inventory

    Vermicomposting -- the biological degradation of organic matter that occurs as earthworms feed on waste materials -- has been advocated by some as a means of stabilizing and disposing of municipal wastewater sludges. Vermicomposting is being attempted on an experimental scale, th...

  2. Industrial wastes and sludges management by vermicomposting

    Microsoft Academic Search

    Anoop Yadav; V. K. Garg

    Vermicomposting has been arising as an innovative ecotechnology for the conversion of various types of wastes into vermicompost.\\u000a Vermicompost is humus like, finely granulated and stabilized material which can be used as a soil conditioner to reintegrate\\u000a the organic matter to the agricultural soils. Industrial wastes remain largely unutilized and often cause environmental problems\\u000a like ground and surface water pollution,

  3. COMPENDIUM ON SOLID WASTE MANAGEMENT BY VERMICOMPOSTING

    EPA Science Inventory

    Vermicomposting of municipal solid wastes has been attempted only in the last five years and there are presently no full-scale operations. This report assesses the technical and economic feasibility of vermicomposting and is based on several pilot-scale studies conducted by priva...

  4. Effect of pre-composting on vermicomposting of kitchen waste.

    PubMed

    Nair, Jaya; Sekiozoic, Vanja; Anda, Martin

    2006-11-01

    The aim of this work was to test combination of the thermocomposting and vermicomposting to improve the treatment efficiency and assess the optimum period required in each method to produce good quality compost. The results showed that pre-thermocomposting improved vermicomposting of kitchen waste. A 9-day thermocomposting prior to vermicomposting helped in mass reduction, moisture management and pathogen reduction. PMID:16269241

  5. Soil agro-ecological management: Fertirrigation and vermicompost treatments

    Microsoft Academic Search

    G. Masciandaro; B. Ceccanti; C. Garcia

    1997-01-01

    A particular wormcasting (vermicompost from biological sludges) and sewage water (from a municipal sewage plant) have been employed in an ecological strategy for the conservation of arable soils. A soil sampled in the south of Italy (Matera), seeded with Avena sativa was used in experiments on: (1) direct incorporation of vermicompost into the soil (VC treatment) and (2) fertirrigation with

  6. Spectroscopic analysis of vermicompost for determination of nutritional quality.

    PubMed

    Subhash Kumar, M; Rajiv, P; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2015-01-25

    Spectroscopic analysis has been carried out to examine the compost quality, maturity and nutritional levels of vermicompost and compost of Eichhornia. 50% Eichhorniacrassipes and 50% cow dung mixtures were vermicomposted using earthworms (Eudrilus eugeniae) and collected on different days' time intervals. Fourier transform infrared spectroscopy (FT-IR) spectra reveal the presence of humic substance from compost and vermicompost, which improves the soil fertility. Gas chromatography-mass spectroscopy (GC-MS) analysis shows maximum level of Benzene propanoic acid (95.98%) and by 2-Propanone, 1-Phenyl-, OXIM (10.10%) from vermicompost through earthworms activity. Atomic absorption spectroscopy (AAS) results reported high level of micronutrient from Eichhornia mediated compost and vermicompost. PMID:25068838

  7. Processing of different types of organic wastes through vermicomposting.

    PubMed

    Bharadwaj, Alok

    2011-07-01

    In the present study, an effort has been made to utilize different types of organic wastes, i.e. kitchen waste, agro residue, institutional waste and cow dung through the process of vermicomposting. These organic wastes were collected separately, air dried, grinded and mixed in 4:1 ratio with cow dung (w/w). During the period of vermicomposting (75 days), different physico-chemical parameters were analyzed separately. During this process, pH, organic carbon, organic matter and C:N ratio of different organic waste mixtures showed a declining trend, however, total nitrogen, available phosphorus and exchangeable potassium contents showed increasing trend with the advancement of vermicomposting period. Besides, physico-chemical investigations of these wastes, estimation of earthworm population, biomass and number of cocoon produced during vermicomposting were also analyzed separately. It was found that earthworm population, biomass and cocoon production increased significantly as the duration of vermicomposting process increased upto 75 days. PMID:23029940

  8. Spectroscopic analysis of vermicompost for determination of nutritional quality

    NASA Astrophysics Data System (ADS)

    Subhash Kumar, M.; Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2015-01-01

    Spectroscopic analysis has been carried out to examine the compost quality, maturity and nutritional levels of vermicompost and compost of Eichhornia. 50% Eichhorniacrassipes and 50% cow dung mixtures were vermicomposted using earthworms (Eudrilus eugeniae) and collected on different days' time intervals. Fourier transform infrared spectroscopy (FT-IR) spectra reveal the presence of humic substance from compost and vermicompost, which improves the soil fertility. Gas chromatography-mass spectroscopy (GC-MS) analysis shows maximum level of Benzene propanoic acid (95.98%) and by 2-Propanone, 1-Phenyl-, OXIM (10.10%) from vermicompost through earthworms activity. Atomic absorption spectroscopy (AAS) results reported high level of micronutrient from Eichhornia mediated compost and vermicompost.

  9. Nutrient recovery from apple pomace waste by vermicomposting technology.

    PubMed

    Hanc, Ales; Chadimova, Zuzana

    2014-09-01

    The present work was focused on vermicomposting apple pomace waste and its mixtures with straw in volume proportions of 25%, 50%, and 75%. The feasibility was evaluated on the basis of agrochemical properties and earthworm biomass. Vermicomposting was able to reduce the weight and volume of the feedstock by 65% and 85%, respectively. The resulting vermicomposts were characterized by slightly acidic to neutral pH (5.9-6.9), and optimal EC (1.6-4.4mS/cm) and C:N ratios (13-14). The total content of nutrients increased during vermicomposting for all of the treatments with the following average final values: N=2.8%, P=0.85%, K=2.3%, and Mg=0.38%. The addition of straw to apple pomace did not enhance earthworm biomass, but did increase the available content of nutrients during vermicomposting. The data reveals that vermicomposting is a suitable technology for the decomposition of apple pomace waste into a value added product. PMID:24582426

  10. Worms, Worms, and Even More Worms: A Vermicomposting Guide for Teachers.

    ERIC Educational Resources Information Center

    California Integrated Waste Management Board, Sacramento.

    This guide is designed to help teachers gain a better understanding of how to get a worm vermicomposting system started. It provides reference curricula materials for using worms in the classroom. Chapters include: (1) "Why Worm Vermicomposting;" (2) "Basics of Vermicomposting;" (3) "Worm Facts;" (4) "Classroom Activities;" (5) "Lab Activities;"…

  11. The use of vermicompost in organic farming: overview, effects on soil and economics.

    PubMed

    Lim, Su Lin; Wu, Ta Yeong; Lim, Pei Nie; Shak, Katrina Pui Yee

    2015-04-01

    Vermicomposting is a process in which earthworms are used to convert organic materials into humus-like material known as vermicompost. A number of researchers throughout the world have found that the nutrient profile in vermicompost is generally higher than traditional compost. In fact, vermicompost can enhance soil fertility physically, chemically and biologically. Physically, vermicompost-treated soil has better aeration, porosity, bulk density and water retention. Chemical properties such as pH, electrical conductivity and organic matter content are also improved for better crop yield. Nevertheless, enhanced plant growth could not be satisfactorily explained by improvements in the nutrient content of the soil, which means that other plant growth-influencing materials are available in vermicomposts. Although vermicomposts have been shown to improve plant growth significantly, the application of vermicomposts at high concentrations could impede growth due to the high concentrations of soluble salts available in vermicomposts. Therefore, vermicomposts should be applied at moderate concentrations in order to obtain maximum plant yield. This review paper discusses in detail the effects of vermicompost on soil fertility physically, chemically and biologically. Future prospects and economy on the use of organic fertilizers in the agricultural sector are also examined. © 2014 Society of Chemical Industry. PMID:25130895

  12. The potential reuse of biodegradable municipal solid wastes (MSW) as feedstocks in vermicomposting.

    PubMed

    Sim, Edwin Yih Shyang; Wu, Ta Yeong

    2010-10-01

    There is an urgent need globally to find alternative sustainable steps to treat municipal solid wastes (MSW) originated from mismanagement of urban wastes with increasing disposal cost. Furthermore, a conglomeration of ever-increasing population and consumerist lifestyle is contributing towards the generation of more MSW. In this context, vermicomposting offers excellent potential to promote safe, hygienic and sustainable management of biodegradable MSW. It has been demonstrated that, through vermicomposting, MSW such as city garbage, household and kitchen wastes, vegetable wastes, paper wastes, human faeces and others could be sustainably transformed into organic fertiliser or vermicompost that provides great benefits to agricultural soil and plants. Generally, earthworms are sensitive to their environment and require temperature, moisture content, pH and sometimes ventilation at proper levels for the optimum vermicomposting process. Apart from setting the optimum operational conditions for the vermicomposting process, other approaches such as pre-composting, inoculating micro-organisms into MSW and redesigning the conventional vermireactor could be introduced to further enhance the vermicomposting of MSW. Thus the present mini-review discusses the potential of introducing vermicomposting in MSW management, the benefits of vermicomposted MSW to plants, suggestions on how to enhance the vermicomposting of MSW as well as risk management in the vermicomposting of MSW. PMID:20718020

  13. Chemical changes during vermicomposting of sago industry solid wastes.

    PubMed

    Subramanian, Selvi; Sivarajan, M; Saravanapriya, S

    2010-07-15

    A laboratory study was undertaken to examine the temporal changes in physico-chemical properties during vermicomposting of sago industry waste. The sago industry waste was blended with cow dung, poultry manure at various proportions, kept for pre-treatment for 21 days and subsequently vermicomposted for a period of 45 days under shade. Earthworm species (Eisenia foetida) was introduced at the rate of 50 g/kg of waste. The substrate moisture content and temperature were monitored regularly. The vermicomposts were sampled at 0, 15, 30 and 45 days for the assessment of temporal changes in physico-chemical properties. The data revealed vermicomposting of sago wastes, cow dung and poultry manure mixed at equal proportion (1:1:1) produced a superior quality manure with desirable C:N ratio and higher nutritional status than composting. E. foetida is an earthworm suitable for composting organic wastes such as poultry manure with extreme pH and high temperature and sago waste with high organic carbon in a shorter period of time. This study suggests that the sago industry solid waste could be effectively converted into highly valuable manure that can be exploited to promote crop production. PMID:20359816

  14. [Effects of herb residue vermicompost on maize growth and soil fertility].

    PubMed

    Li, Jing-Juan; Zhou, Bo; Zhang, Chi; Zhang, Jing; Xu, Huan; Yang, Xiao-Xue; Chen, Xu-Fei; Dai, Jun

    2013-09-01

    A pot experiment was conducted to evaluate the effects of herb residue vermicompost on maize growth and soil fertility. With the increasing application rate of vermicompost, the plant height, stem diameter, leaf area, and chlorophyll content of maize all increased significantly. After 60 days growth of maize, the soil bulk density in most vermicompost treatments decreased significantly. The soil pH in vermicompost treatments was significantly higher than that in CK and in chemical fertilization treatments. In addition, the soil total nitrogen and organic matter contents in vermicompost treatments were obviously higher than those in chemical fertilization treatments. It was suggested that herb residue vermicompost could be used as an efficient and high-quality organic fertilizer, and its appropriate application could improve soil physical structure, alleviate soil acidification, increase soil organic matter and nitrogen contents, and promote crop growth. PMID:24417126

  15. Waste recycling: utilization of coffee grounds and kitchen waste in vermicomposting.

    PubMed

    Adi, A J; Noor, Z M

    2009-01-01

    Vermicomposting using Lumbricus rubellus for 49 days was conducted after 21 days of pre-composting. Three different combination of treatments were prepared with eight replicates for each treatment namely cow dung: kitchen waste in 30:70 ratio (T(1)), cow dung: coffee grounds in 30:70 ratio (T(2)), and cow dung: kitchen waste: coffee grounds in 30:35:35 ratio (T(3)). The multiplication of earthworms in terms of numbers and weight were measured at the end of vermicomposting. Consequently, only T(2) showed significant increase (from it initial stage) compared to other treatments. The presence of coffee grounds in T(2) and T(3) showed higher percentage of nutrient elements in vermicompost produced. The data reveal that coffee grounds can be decomposed through vermicomposting and help to enhance the quality of vermicompost produced rather than sole use of kitchen waste in vermicomposting. PMID:18752936

  16. Vermicompost as a Soil Supplement to Improve Growth and Yield of Parsley

    Microsoft Academic Search

    Gh. Peyvast; J. A. Olfati; S. Madeni; A. Forghani; H. Samizadeh

    2008-01-01

    Organically based nutrient sources may provide an alternative to synthetic fertilizers to provide nutrition for plants. Vermicomposting may be able to mitigate problems with detrimental microbes, especially thermo-tolerant pathogens in conventional compost. Information is lacking on effects of vermicomposted animal manure on leafy vegetables. Vermicomposted cattle manure, in combinations with soil [0:100, 10:100, 20:100, and 30:100 (v\\/v)], was tested to

  17. Influence of vermicomposting on solid wastes decomposition kinetics in soils*

    PubMed Central

    Nourbakhsh, Farshid

    2007-01-01

    The effect of vermicomposting on kinetic behavior of the products is not well recognized. An incubation study was conducted to investigate C mineralization kinetics of cow manure, sugarcane filter cake and their vermicomposts. Two different soils were treated with the four solid wastes at a rate of 0.5 g solid waste C per kg soil with three replications. Soils were incubated for 56 d. The CO2-C respired was monitored periodically and a first-order kinetic model was used to calculate the kinetic parameters of C mineralization. Results indicated that the percentage of C mineralized during the incubation period ranged from 31.9% to 41.8% and 55.9% to 73.4% in the calcareous and acidic soils, respectively. The potentially mineralizable C (C 0) of the treated soils was lower in the solid waste composts compared to their starting materials. Overall, it can be concluded that decomposable fraction of solid wastes has decreased due to vermicomposting. PMID:17910115

  18. Evaluation of Proportions of Vermicompost and Coir in a Medium for Container-Grown Swiss Chard

    Microsoft Academic Search

    L. Abbey; C. Young; R. Teitel-Payne; K. Howe

    2012-01-01

    A mixture of vermicompost and coir is commonly used for growing plants. However, the extent to which variation in proportions of these substrates in a mixture affects plant growth is not known. A study was carried out in a greenhouse to determine appropriate proportions of vermicompost and coir mixture to produce the most suitable medium conditions for growing Swiss chard

  19. Vermicompost Effects on the Growth and Flowering of Petunia hybrida 'Dream Neon Rose

    Microsoft Academic Search

    E. Chamani; D. C. Joyce; A. Reihanytabar

    2008-01-01

    The effects of vermicompost of an animal manure origin on the growth and flowering of Petunia hybrida 'Dream Neon Rose' grown under glasshouse conditions were determined. Petunia seeds were germinated, transplanted into media and grown-on for 150 days. The traditional base medium (control) was a mix ture of 70% farm soil and 30% sand (v\\/v). Treatments were either vermicompost incorporated

  20. Evaluation of vermicompost maturity using scanning electron microscopy and paper chromatography analysis.

    PubMed

    Senthil Kumar, D; Satheesh Kumar, P; Rajendran, N M; Uthaya Kumar, V; Anbuganapathi, G

    2014-04-01

    Vermicompost was produced from flower waste inoculated with biofertilizers using the earthworm Eisenia fetida. Principal component analysis (PCA) and cluster analysis (CA) were carried out on the basis of physicochemical parameters of vermicomposted samples. From the results of the PCA and CA, it was possible to classify two different groups of vermicompost samples in the following categories: E2 and E5; and E1, E3, E4, and control. Scanning electron microscopy and biodynamic circular paper chromatography analysis were used to investigate the changes in surface morphology and functional groups in the control and vermicompost products. SEM analysis of E1-E5 shows more fragment and pores than the control. Chromatographic analysis of vermicompost indicated the mature condition of the compost materials. PMID:24634991

  1. Microbial diversity of vermicompost bacteria that exhibit useful agricultural traits and waste management potential.

    PubMed

    Pathma, Jayakumar; Sakthivel, Natarajan

    2012-01-01

    Vermicomposting is a non-thermophilic, boioxidative process that involves earthworms and associated microbes. This biological organic waste decomposition process yields the biofertilizer namely the vermicompost. Vermicompost is a finely divided, peat like material with high porosity, good aeration, drainage, water holding capacity, microbial activity, excellent nutrient status and buffering capacity thereby resulting the required physiochemical characters congenial for soil fertility and plant growth. Vermicompost enhances soil biodiversity by promoting the beneficial microbes which inturn enhances plant growth directly by production of plant growth-regulating hormones and enzymes and indirectly by controlling plant pathogens, nematodes and other pests, thereby enhancing plant health and minimizing the yield loss. Due to its innate biological, biochemical and physiochemical properties, vermicompost may be used to promote sustainable agriculture and also for the safe management of agricultural, industrial, domestic and hospital wastes which may otherwise pose serious threat to life and environment. PMID:23961356

  2. Vermicomposting of source-separated human faeces by Eisenia fetida: effect of stocking density on feed consumption rate, growth characteristics and vermicompost production.

    PubMed

    Yadav, Kunwar D; Tare, Vinod; Ahammed, M Mansoor

    2011-06-01

    The main objective of the present study was to determine the optimum stocking density for feed consumption rate, biomass growth and reproduction of earthworm Eisenia fetida as well as determining and characterising vermicompost quantity and product, respectively, during vermicomposting of source-separated human faeces. For this, a number of experiments spanning up to 3 months were conducted using soil and vermicompost as support materials. Stocking density in the range of 0.25-5.00 kg/m(2) was employed in different tests. The results showed that 0.40-0.45 kg-feed/kg-worm/day was the maximum feed consumption rate by E. fetida in human faeces. The optimum stocking densities were 3.00 kg/m(2) for bioconversion of human faeces to vermicompost, and 0.50 kg/m(2) for earthworm biomass growth and reproduction. PMID:21377345

  3. Effects of combined composting and vermicomposting of waste sludge on arsenic fate and bioavailability.

    PubMed

    Ma?áková, Blanka; Kuta, Jan; Svobodová, Markéta; Hofman, Jakub

    2014-09-15

    Composting and vermicomposting are traditional processes for the treatment of sludge. During these processes, the humification of organic matter has a significant effect on the physicochemical form and distribution of heavy metals. In this study, industrial sludge (groundwater treatment waste) contaminated by arsenic (396 ± 1 mg kg(-1)) was used. Such sludge poses a significant challenge with respect to effective treatment. Composting, vermicomposting (with Eisenia fetida), and the combined approach of composting and vermicomposting were performed to determine the evolution of arsenic speciation, mobility and bioavailability. The composting/vermicomposting was done with sludge, horse manure, and grass in the ratios of 3:6:1. A solution of 0.1M NH4COOCH3 was used as a single extraction solvent for determination of the mobile arsenic pool and targeted arsenic species (As(III), As(V), monomethylarsenic acid - MMA(V), dimethylarsenic acid - DMA(V)). The analysis of arsenic in the extracts was carried out by means of HPLC-ICP-MS spectrometry. In addition, the earthworm species E. fetida was used for bioaccumulation tests that followed the compost and vermicompost processes. The obtained results indicate a reduction in arsenic mobility and bioavailability in all matured composts and vermicomposts. The combined process exhibited a greater effect than compost or vermicompost alone. PMID:25209831

  4. Neem leaves as a source of fertilizer-cum-pesticide vermicompost

    Microsoft Academic Search

    S. Gajalakshmi; S. A. Abbasi

    2004-01-01

    Vermicomposting of neem (Azadirachta indica A. Juss) was accomplished in ‘high-rate’ reactors operated at the earthworm (Eudrilus eugeniae) densities of 62.5 and 75 animals per litre of reactor volume. Contrary to the fears that neem––a powerful nematicide––might not be palatable to the annelids, the earthworms fed voraciously on the neem compost, converting upto 7% of the feed into vermicompost per

  5. Livestock excreta management through vermicomposting using an epigeic earthworm Eisenia foetida

    Microsoft Academic Search

    V. K. Garg; Y. K. Yadav; Aleenjeet Sheoran; Subhash Chand; Priya Kaushik

    2006-01-01

    In India, millions of tones of livestock excreta are produced. Our study explores the potential of an epigeic earthworm Eisenia foetida to compost different livestock excreta (cow, buffalo, horse, donkey, sheep, goat and camel) into value added product (vermicompost)\\u000a at the laboratory scale. Vermicomposting resulted in lowering of pH, electrical conductivity, potassium and C:N ratio and\\u000a increase in nitrogen and

  6. Vermicomposting as manure management strategy for urban small-holder animal farms - Kampala case study.

    PubMed

    Lalander, Cecilia Helena; Komakech, Allan John; Vinnerås, Björn

    2015-05-01

    Inadequate organic waste management can contribute to the spread of diseases and have negative impacts on the environment. Vermicomposting organic waste could have dual beneficial effects by generating an economically viable animal feed protein in the form of worm biomass, while alleviating the negative effects of poor organic waste management. In this study, a low-maintenance vermicomposting system was evaluated as manure and food waste management system for small-holder farmers. A vermicomposting system using the earthworm species Eudrilus eugeniae and treating cow manure and food waste was set up in Kampala, Uganda, and monitored for 172days. The material degradation and protein production rates were evaluated after 63days and at the end of the experiment. The material reduction was 45.9% and the waste-to-biomass conversion rate was 3.5% in the vermicomposting process on a total solids basis. A possible increase in the conversion rate could be achieved by increasing the frequency of worm harvesting. Vermicomposting was found to be a viable manure management method in small-scale urban animal agriculture; the return of investment was calculated to be 280% for treating the manure of a 450kg cow. The vermicompost was not sanitised, although hygiene quality could be improved by introducing a post-stabilisation step in which no fresh material is added. The value of the animal feed protein generated in the process can act as an incentive to improve current manure management strategies. PMID:25728090

  7. Impact of imidacloprid residues on the development of Eisenia fetida during vermicomposting of greenhouse plant waste.

    PubMed

    Fernández-Gómez, Manuel J; Romero, Esperanza; Nogales, Rogelio

    2011-09-15

    Pesticide application in agriculture causes residues in post-harvest plant waste at different concentrations. Knowledge concerning how pesticide concentrations in such waste affect earthworms is essential for recycling greenhouse plant debris through vermicomposting. Here, we have evaluated the effects of imidacloprid (IMD) residues on earthworms (Eisenia fetida) during the vermicomposting of plant waste from greenhouse crops in Spain. Before, the effect of different IMD concentrations on earthworms was tested using cattle manure as an optimum waste for worm development. The results after using cattle manure indicate that IMD dose ? 5 mg kg(-1) hinders worm growth and even causes death, whereas IMD dose ? 2 mg IMD kg(-1) allows worm growth similar to control but impedes reproduction. The results from the vermicomposting of plant waste reveal that IMD inhibits adequate worm growth and increases mortality. Although 89% worms became sexually mature in substrate containing 2 mg IMD kg(-1), they did not produce cocoons. IMD also affected microorganisms harboured in the substrates for vermicomposting, as indicated by the reduction in their dehydrogenase activity. This enzyme activity was restored after vermicomposting. This study provides a sound basis for the vermicomposting of pesticide-contaminated plant waste. PMID:21775059

  8. Towards understanding the stabilization process in vermicomposting using PARAFAC analysis of fluorescence spectra.

    PubMed

    Lv, Baoyi; Xing, Meiyan; Zhao, Chunhui; Yang, Jian; Xiang, Liang

    2014-12-01

    In this study, fluorescence excitation-emission matrix (EEM) combined with parallel factor analysis (PARAFAC) was employed to trace the behavior of water extractable organic matter and assess the stabilization process during vermicomposting of sewage sludge and cattle dung. Experiments using different mixing ratios of sewage sludge and cattle dung were conducted using Eisenia fetida. The results showed that vermicomposting reduced the DOC, DOC/DON ratio and ammonia, while increased the nitrate content. A three-component model containing two humic-like materials (components 1 and 2) and a protein-like material (component 3) was successfully developed using PARAFAC analysis. Moreover, the initial waste composition had a significant effect on the distribution of each component and the addition of cattle dung improved the stability of sewage sludge in vermicomposting. The PARAFAC results also indicated that protein-like materials were degraded and humic acid-like compounds were evolved during vermicomposting. Pearson correlation analysis showed that components 2 and 3 are more suitable to assess vermicompost maturity than component 1. In all, EEM-PARAFAC can be used to track organic transformation and assess biological stability during the vermicomposting process. PMID:25068534

  9. Removal of Cu, Cr, Ni, Zn, and Cd from electroplating wastes and synthetic solutions by vermicompost of cattle manure.

    PubMed

    Jordão, Cláudio Pereira; Pereira, Madson de Godoi; Einloft, Rosilene; Santana, Marlete Bastos; Bellato, Carlos Roberto; de Mello, Jaime Wilson Vargas

    2002-01-01

    This study was undertaken to evaluate the retention of Cu, Cr, Ni, Zn, and Cd under laboratory conditions from synthetic solution and electroplating wastes by vermicompost. A glass column was loaded with vermicompost, and metal solutions were passed through it. Metal concentrations were then measured in the eluate in order to evaluate the amounts retained by the vermicompost. Measurements of pH, metal concentrations, moistness, organic matter and ash contents, and infrared and XRD spectroscopy were used for vermicompost characterisation. Vermicompost residues obtained from this process were used for plant nutrition in eroded soil collected from a talus near a highway. Metal retention (in g of metal/kg of vermicompost) from effluents ranged from 2 for Cr and Zn to 4 in the case of Ni. In synthetic solutions, the values for metal retention were 4 for Cd and Zn, 6 for Cu and Ni, and 9 for Cr. The results also showed that metal concentrations in the purified effluents were below the maximum values established for waste discharges into rivers by the Brazilian Environmental Standards. The relatively high available Cd concentration of the vermicompost residue resulted in plant damage. This effect was attributed to the presence of Cd in the synthetic solution passed through the vermicompost. The data obtained do not give a complete picture of using vermicompost in cultivated lands, but such values as are determined do show that it can be suitable to remove heavy metals from industrial effluents. PMID:12049122

  10. Impact of Parthenium weeds on earthworms (Eudrilus eugeniae) during vermicomposting.

    PubMed

    Rajiv, P; Rajeshwari, Sivaraj; Rajendran, Venckatesh

    2014-11-01

    The aim of this work is to evaluate the effect of Parthenium-mediated compost on Eudrilus eugeniae during the process of vermicomposting. Nine different concentrations of Parthenium hysterophorus and cow dung mixtures were used to assess toxicity. The earthworms' growth, fecundity and antioxidant enzyme levels were analysed every 15 days. The antioxidant activities of enzymes [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)], considered as biomarkers, indicate the biochemical and oxidative stresses due to the toxin from Parthenium weeds. The earthworms' growth, biomass gain, cocoon production and antioxidant enzymes were in a low level in a high concentration of P. hysterophorus (without cow dung). The results clearly indicated that appropriate mixing of P. hysterophorus quantity is an essential factor for the survival of earthworms without causing any harm. PMID:24938809

  11. Effect of aqueous extracts from vermicomposts on attacks by cucumber beetles ( Acalymna vittatum) (Fabr.) on cucumbers and tobacco hornworm ( Manduca sexta) (L.) on tomatoes

    Microsoft Academic Search

    Clive A. Edwards; Norman Q. Arancon; Marcus Vasko-Bennett; Ahmed Askar; George Keeney

    2010-01-01

    Vermicomposts are produced through interactions between earthworms and microorganisms in the breakdown of organic wastes. Aqueous extracts were prepared in commercial brewing equipment from vermicomposts produced from super-market food wastes. The ratio of vermicompost to water was one to five v:v, to produce a 20% aqueous solution which could be diluted to 5% and 10% concentrations. The effects of soil

  12. Heavy metal behavior and dissolved organic matter (DOM) characterization of vermicomposted pig manure amended with rice straw.

    PubMed

    Zhu, Weiqin; Yao, Wu; Zhang, Zhi; Wu, Yang

    2014-11-01

    Vermicomposting is an eco-friendly method for disposing of livestock and poultry manure. In addition, dissolved organic matter (DOM) can serve as a carrier that enhances the migration and transformation of heavy metals. Here, pig manure amended with rice straw was vermicomposted with Eisenia fetida. The DOM content, molecular weight distribution, and spectroscopic properties of the amended pig manure were measured before and after vermicomposting. The Cu and Zn concentrations in the earthworms increased from 8.24 and 17.63 to 40.75 and 362.78 mg/kg separately after vermicomposting, and the earthworms also increased the heavy metal availability in the vermicompost. Relative to the DOM properties of conventional compost, the DOM molecular weight decreased and varied widely following vermicomposting, and the C/N ratio of the DOM in the vermicompost treatments decreased from 10.37 to 8.60. The Fourier transform far-infrared (FTIR) and fluorescence spectra of the DOM indicated that the amounts of oxygen-containing structures increased while the ratio of humic acid to fulvic acid decreased following vermicomposting. Accordingly, the earthworms augmented the heavy metal mitigation risk in the pig manure. This augment potentially resulted from the decreased humic acid-to-fulvic acid (HA/FA) ratio from DOM structural changes. PMID:24958537

  13. Fourier transform-infrared spectroscopy and Gas chromatography-mass spectroscopy: reliable techniques for analysis of Parthenium mediated vermicompost.

    PubMed

    Rajiv, P; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2013-12-01

    Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectroscopy have been carried out to investigate the chemical composition of Parthenium mediated vermicompost. Four different concentrations of Parthenium and cow dung mixtures were vermicomposted using the earthworms (Eudrilus eugeniae). FT-IR spectra reveal the absence of Parthenin toxin (sesquiterpene lactone) and phenols in vermicompost which was obtained from high concentration of cow dung mixed treatments. GC-MS analysis shows no phenolic compounds and predominant level of intermediate metabolites such as 4,8,12,16-Tetramethylheptadecan-4-olide (7.61%), 2-Pentadecanone, 6,10,14-trimethyl- (5.29%) and Methyl 16-methyl-heptadecanoate (4.69%) during the vermicomposting process. Spectral results indicated that Parthenin toxin and phenols can be eradicated via vermicomposting if mixed with appropriate quantity of cow dung. PMID:23998948

  14. Insight into the roles of earthworm in vermicomposting of sewage sludge by determining the water-extracts through chemical and spectroscopic methods.

    PubMed

    Yang, Jian; Lv, Baoyi; Zhang, Jie; Xing, Meiyan

    2014-02-01

    This work illustrated the effects of earthworm in vermicomposting (Eisenia fetida) by determining the water-extracts through chemical and spectroscopic methods. A field experiment with sludge as the only feed was subjected to vermicomposting and the control (without worms) for three weeks. Compared to the control, vermicomposting resulted in lower pH and water-extractable organic carbon (WEOC) along with higher electrical conductivity (EC). Moreover, vermicomposting caused nearly two times higher content of water-extractable nitrate (WEN-NO3(-)) than the control. Furthermore, fourier transform infrared spectra (FT-IR) revealed that vermicomposting promoted the hydrolysis/transformation of macromolecular organic matters and accelerated the degradation of polysaccharide-like and protein-like materials. Fluorescence spectroscopy also reflected vermicomposting led to higher humification degree than the control. In all, this study supplies a new view to assess the roles of earthworm in vermicomposting of sewage sludge by evaluating the water extracts. PMID:24384315

  15. Molecular characteristics of humic acids isolated from vermicomposts and their relationship to bioactivity.

    PubMed

    Martinez-Balmori, Dariellys; Spaccini, Riccardo; Aguiar, Natália Oliveira; Novotny, Etelvino Henrique; Olivares, Fábio Lopes; Canellas, Luciano Pasqualoto

    2014-11-26

    Vermitechnology is an effective composting method, which transforms biomass into nutrient-rich organic fertilizer. Mature vermicompost is a renewable organic product containing humic substances with high biological activity. The aim of this study was to assess the chemical characteristics and the bioactivity of humic acids isolated from different vermicomposts produced with either cattle manure, sugar cane bagasse, sunflower cake from seed oil extraction, or filter cake from a sugar cane factory. More than 200 different molecules were found, and it was possible to identify chemical markers on humic acids according to the nature of the organic source. The large hydrophobic character of humic extracts and the preservation of altered lignin derivatives confer to humic acids the ability to induce lateral root emergence in maize seedlings. Humic acid-like substances extracted from plant biomass residues represent an additional valuable product of vermicomposting that can be used as a plant growth promoter. PMID:25379603

  16. An Overview of the Environmental Applicability of Vermicompost: From Wastewater Treatment to the Development of Sensitive Analytical Methods

    PubMed Central

    Pereira, Madson de Godoi; Cardoso de Souza Neta, Lourdes; Fontes, Maurício Paulo Ferreira; Souza, Adriana Nascimento; Carvalho Matos, Thaionara; de Lima Sachdev, Raquel; dos Santos, Arnaud Victor; Oliveira da Guarda Souza, Marluce; de Andrade, Marta Valéria Almeida Santana; Marinho Maciel Paulo, Gabriela; Ribeiro, Joselito Nardy; Verónica Flores Nardy Ribeiro, Araceli

    2014-01-01

    The use of vermicompost (humified material) for treating wastewaters, remediating polluted soils, improving agricultural productivity, protecting crop production, and developing sensitive analytical methods is reviewed here, covering the past 17 years. The main advantages of vermicompost, considering all applications covered in this paper, comprise (i) easy acquisition, (ii) low costs, (iii) structural, chemical, and biological characteristics responsible for exceptional adsorptive capacities as well as pollutant degradation, and (iv) the promotion of biocontrol. Specifically, for wastewater decontamination, a considerable number of works have verified the adsorption of toxic metals, but the application of vermicompost is still scarce for the retention of organic compounds. Problems related to the final disposal of enriched vermicompost (after treatment steps) are often found, in spite of some successful destinations such as organic fertilizer. For decontaminating soils, the use of vermicompost is quite scarce, mainly for inorganic pollutants. In agricultural productivity and biocontrol, vermicompost imparts remarkable benefits regarding soil aggregation, plant nutrition, and the development of beneficial microorganisms against phytopathogens. Finally, the use of vermicompost in sensitive analytical methods for quantifying toxic metals is the newest application of this adsorbent. PMID:24578668

  17. An overview of the environmental applicability of vermicompost: from wastewater treatment to the development of sensitive analytical methods.

    PubMed

    Pereira, Madson de Godoi; Neta, Lourdes Cardoso de Souza; Fontes, Maurício Paulo Ferreira; Souza, Adriana Nascimento; Matos, Thaionara Carvalho; Sachdev, Raquel de Lima; dos Santos, Arnaud Victor; da Guarda Souza, Marluce Oliveira; de Andrade, Marta Valéria Almeida Santana; Paulo, Gabriela Marinho Maciel; Ribeiro, Joselito Nardy; Ribeiro, Araceli Verónica Flores Nardy

    2014-01-01

    The use of vermicompost (humified material) for treating wastewaters, remediating polluted soils, improving agricultural productivity, protecting crop production, and developing sensitive analytical methods is reviewed here, covering the past 17 years. The main advantages of vermicompost, considering all applications covered in this paper, comprise (i) easy acquisition, (ii) low costs, (iii) structural, chemical, and biological characteristics responsible for exceptional adsorptive capacities as well as pollutant degradation, and (iv) the promotion of biocontrol. Specifically, for wastewater decontamination, a considerable number of works have verified the adsorption of toxic metals, but the application of vermicompost is still scarce for the retention of organic compounds. Problems related to the final disposal of enriched vermicompost (after treatment steps) are often found, in spite of some successful destinations such as organic fertilizer. For decontaminating soils, the use of vermicompost is quite scarce, mainly for inorganic pollutants. In agricultural productivity and biocontrol, vermicompost imparts remarkable benefits regarding soil aggregation, plant nutrition, and the development of beneficial microorganisms against phytopathogens. Finally, the use of vermicompost in sensitive analytical methods for quantifying toxic metals is the newest application of this adsorbent. PMID:24578668

  18. Effects of vermicomposts on growth and marketable fruits of field-grown tomatoes, peppers and strawberries

    Microsoft Academic Search

    Norman Q. Arancon; Clive A. Edwards; Peter Bierman; James D. Metzger; Stephen Lee; Christie Welch

    2003-01-01

    Summary Vermicomposts, produced commercially from cattle manure, market food waste and recycled paper waste, were applied to small replicated field plots planted with tomatoes (Lycopersicon esculentum) and bell peppers (Capsicum anuum grossum) at rates of 10 t ha-1 or 20 t ha-1 in 1999 and at rates of 5 t ha-1 or 10 t ha-1 in 2000. Food waste and

  19. Production of Eisenia fetida and vermicompost from feed-lot cattle manure

    Microsoft Academic Search

    Allan Mitchell

    1997-01-01

    Significant reductions in total mass of feedlot cattle manure were obtained by the intensive activity of earthworms. The process yielded two products: residual vermicompost, and an increase in earthworm biomass. Various modes of manure application were made to a prepared bedding (or support material), the most successful being a surface (vertical) application which resulted in a reduction of 30% of

  20. Vermicomposting of industrially produced woodchips and sewage sludge utilizing Eisenia fetida

    Microsoft Academic Search

    M. S. Maboeta; L. van Rensburg

    2003-01-01

    Adult Eisenia fetida were used to vermicompost woodchips (WC) and sewage sludge (SS) that are produced as waste product by platinum mines. The aims of the study were to examine the growth and reproductive success of the worms over 84 days to determine long-term feasibility of large-scale implementation and monitor the bioconcentration of heavy metals and the effects of microorganisms

  1. Integrating composting and vermicomposting in the treatment and bioconversion of biosolids

    Microsoft Academic Search

    P. M Ndegwa; S. A Thompson

    2001-01-01

    Traditional thermophillic composting is commonly adopted for treatment of organic wastes or for production of organic\\/natural fertilizers. A related technique, called vermicomposting (using earthworms to breakdown the organic wastes) is also becoming popular. These two techniques have their inherent advantages and disadvantages. The integrated approach suggested in this study borrows pertinent attributes from each of these two processes and combines

  2. Composting with Worms Worm composting (or vermicomposting) is a natural and efficient way to recycle your

    E-print Network

    New Hampshire, University of

    Composting with Worms Worm composting (or vermicomposting) is a natural and efficient way to recycle your organic kitchen scraps. And it sure beats plowing through knee-high snowdrifts to the compost project to do with kids; it's easy to make compost using worms as long as you have the right container

  3. Food Scrap Vermicomposting and Composting Update John Biernbaum and Brooke Comer, Department of Horticulture

    E-print Network

    Food Scrap Vermicomposting and Composting Update John Biernbaum and Brooke Comer, Department survival. A concrete pad with a high tunnel cover was constructed and allowed food scrap hot composting recipes were hot composted during the summer and final products are being evaluated for effectiveness

  4. Potential utilization of bagasse as feed material for earthworm Eisenia fetida and production of vermicompost.

    PubMed

    Bhat, Sartaj Ahmad; Singh, Jaswinder; Vig, Adarsh Pal

    2015-01-01

    In the present work bagasse (B) i.e waste of the sugar industry, was fed to Eisenia fetida with cattle dung (CD) support as feed material at various ratios (waste: CD) of 0:100 (B0), 25:75 (B25), 50:50 (B50), 75:25 (B75) and 100:0 (B100) on dry weight basis. Co-composting with cattle dung helped to improve their acceptability for E. fetida and also improved physico-chemical characteristics. Best appropriate ratio for survival, maximum growth and population buildup of E. fetida was determined by observing population buildup, growth rate, biomass, mortality and cocoon formation. Minimum mortality and highest population size of worms was observed in 50:50 (B50) ratio. Increasing concentrations of wastes significantly affected the growth and reproduction of worms. Nutrients like nitrogen, phosphorus and sodium increased from pre-vermicompost to post-vermicompost, while organic carbon, and C:N ratio decreased in all the end products of post-vermicomposting. Heavy metals decreased significantly from initial except zinc, iron and manganese which increased significantly. Scanning electron microscopy (SEM) was used to recognize the changes in texture in the pre and post-vermicomposted samples. The post-vermicomposted ratios in the presence of earthworms validate more surface changes that prove to be good manure. The results observed from the present study indicated that the earthworm E. fetida was able to change bagasse waste into nutrient-rich manure and thus play a major role in industrial waste management. PMID:25625035

  5. Chemical and microbiological changes during vermicomposting of coffee pulp using exotic (Eudrilus eugeniae) and native earthworm (Perionyx ceylanesis) species.

    PubMed

    Raphael, Kurian; Velmourougane, K

    2011-06-01

    Coffee pulp is the main solid residue from the wet processing of coffee berries. Due to presence of anti-physiological and anti-nutritional factors, coffee pulp is not considered as adequate substrate for bioconversion process by coffee farmers. Recent stringent measures by Pollution Control authorities, made it mandatory to treat all the solid and liquid waste emanating from the coffee farms. A study was conducted to evaluate the efficiency of an exotic (Eudrilus eugeniae) and a native earthworm (Perionyx ceylanesis) from coffee farm for decomposition of coffee pulp into valuable vermicompost. Exotic earthworms were found to degrade the coffee pulp faster (112 days) as compared to the native worms (165 days) and the vermicomposting efficiency (77.9%) and vermicompost yield (389 kg) were found to significantly higher with native worms. The multiplication rate of earthworms (280%) and worm yield (3.78 kg) recorded significantly higher with the exotic earthworms. The percentage of nitrogen, phosphorous, potassium, calcium and magnesium in vermicompost was found to increase while C:N ratio, pH and total organic carbon declined as a function of the vermicomposting. The plant nutrients, nitrogen (80.6%), phosphorus (292%) and potassium (550%) content found to increase significantly in the vermicompost produced using native earthworms as compared to the initial values, while the calcium (85.7%) and magnesium (210%) content found to increase significantly in compost produced utilizing exotic worms. Vermicompost and vermicasts from native earthworms recorded significantly higher functional microbial group's population as compared to the exotic worms. The study reveals that coffee pulp can be very well used as substrate for vermicomposting using exotic (Eudrilus eugeniae) and native earthworm (Perionyx ceylanesis). PMID:20922463

  6. Efficacy of Vermicompost against fertilizers on Cicer and Pisum and on population diversity of N2 fixing bacteria.

    PubMed

    Sinha, Jayanta; Biswas, Chanchal Kumar; Ghosh, Arup; Saha, Amit

    2010-05-01

    Vermicompost is a very important biofertilizer produced through the artificial cultivation of worms i.e. Vermiculture. Vermicompost is enriched with all beneficial soil bacteria and also contain many of the essential plant nutrients like N, P, K and micronutrients. It increases soil aeration, texture and jilt. In this work, study is being carried out to find out the effect of different fertilizers such as DAF, FYM and Vermicompost on various morphological parameters and on the in vitro growth of bacterial colonies and its diversity in relation to two important leguminous plants such as Pisum sp. and Cicer sp. Results showed that plant grown in Vermicompost pretreated soil exhibited maximum increase in all morphological parameters such as root length, shoot length, number of root branches, number of stem branches, number of leaves, number of flowers, number of pods and number of root nodules in four months sampling in comparison to untreated, FYM treated and DAP treated soils. Further in Vermicompost pretreated soil, number of N2 fixing bacterial colony was maximum and showed highest diversity indices (1.6 and 0.99 and 2.0 and 0.99 for Cicer sp. and Pisum sp. respectively) than FYM, DAP and untreated control. Thus not only does the Vermicompost stimulate plant growth but also it increases the N2 fixing bacterial population in soil and also its diversity. PMID:21046998

  7. Changes in organic - C, N, P and K and enzyme activities in vermicompost of biodegradable organic wastes under liming and microbial inoculants.

    PubMed

    Pramanik, P; Ghosh, G K; Ghosal, P K; Banik, P

    2007-09-01

    The aim of this work was to study the effect of different organic wastes, viz. cow dung, grass, aquatic weeds and municipal solid waste with lime and microbial inoculants on chemical and biochemical properties of vermicompost. Cow dung was the best substrate for vermicomposting. Application of lime (5 g/kg) and inoculation of microorganisms increased the nutrient content in vermicompost and also phosphatases and urease activities. Bacillus polymyxa, the free-living N-fixer, increased N-content of vermicompost significantly (p < or = 0.01) as compared to other inoculants. PMID:17081750

  8. Application of a set of complementary techniques to understand how varying the proportion of two wastes affects humic acids produced by vermicomposting.

    PubMed

    Fernández-Gómez, Manuel J; Nogales, Rogelio; Plante, Alain; Plaza, César; Fernández, José M

    2015-01-01

    A better understanding of how varying the proportion of different organic wastes affects humic acid (HA) formation during vermicomposting would be useful in producing vermicomposts enriched in HAs. With the aim of improving the knowledge about this issue, a variety of analytical techniques [UV-visible spectroscopic, Fourier transform infrared, fluorescence spectra, solid-state cross-polarization magic-angle spinning (CPMAS) (13)C nuclear magnetic resonance (NMR) spectra, and thermal analysis] was used in the present study to characterize HAs isolated from two mixtures at two different ratios (2:1 and 1:1) of tomato-plant debris (TD) and paper-mill sludge (PS) before and after vermicomposting. The results suggest that vermicomposting increased the HA content in the TD/PS 2:1 and 1:1 mixtures (15.9% and 16.2%, respectively), but the vermicompost produced from the mixture with a higher amount of TD had a greater proportion (24%) of HAs. Both vermicomposting processes caused equal modifications in the humic precursors contained in the different mixtures of TD and PS, and consequently, the HAs in the vermicomposts produced from different waste mixtures exhibited analogous characteristics. Only the set of analytical techniques used in this research was able to detect differences between the HAs isolated from each type of vermicompost. In conclusion, varying the proportion of different wastes may have a stronger influence on the amount of HAs in vermicomposts than on the properties of HAs. PMID:25318702

  9. Changes in chemical and microbiological properties of rabbit manure in a continuous-feeding vermicomposting system.

    PubMed

    Gómez-Brandón, María; Lores, Marta; Domínguez, Jorge

    2013-01-01

    In the present study the potential of the earthworm Eisenia fetida to process large amounts of waste was evaluated through continuous feeding reactors in which new layers of rabbit manure were added sequentially to form an age gradient inside the reactors. An optimal moisture level, ranging from 66% to 76%, was maintained throughout the process using an automatic watering system. The pH was close to 8.3, but decreased to 7.6 after 200 d of vermicomposting. No changes in electrical conductivity through the profile of layers were detected. Based on comparisons of phospholipid fatty acid (PLFA) profiles and microbial activity measurements (basal respiration), a decrease in the levels of bacteria and fungi in layers corresponding to vermicomposting times of more than 200 d occurred. This points to a higher degree of stabilisation in the final product, which is of utmost importance for its safe use as an organic amendment. PMID:23196253

  10. Direct, rapid and sustainable vermicomposting of the leaf litter of neem (Azadirachta indica).

    PubMed

    Nayeem-Shah, M; Gajalakshmi, S; Abbasi, S A

    2015-01-01

    The recently developed concept of high rate vermicomposting was successfully used to enable direct vermicomoposting of neem leaves-without any pre-composting or cow dung supplementation as previously reported processes had necessitated. All the three epigeic species of earthworms that were explored, Eudrilus eugeniae, Eisenia fetida and Perionyx excavatus, provided efficient vermicast production with no mortality, persistent gain in body mass and good fecundity over the 16 months long period of reactor operation. In this period, all reactors were pulse-fed at the solid retention time of 20 days and were operated in the pseudo discretized continuous operation protocol developed earlier by the authors. With this, it was possible to almost completely dampen the influence of natural biodegradation of the feed or grazing by the earthworm born in the vermireactors. The findings, thus, conclusively prove that, all-through, the brisk vermicomposting was caused almost entirely by the action of the 'parent' earthworms on fresh feed. PMID:25344437

  11. Emissions of ammonia and greenhouse gases during combined pre-composting and vermicomposting of duck manure.

    PubMed

    Wang, Jinzhi; Hu, Zhengyi; Xu, Xingkai; Jiang, Xia; Zheng, Binghui; Liu, Xiaoning; Pan, Xubin; Kardol, Paul

    2014-08-01

    Combined pre-composting and vermicomposting has shown potential for reclamation of solid wastes, which is a significant source of ammonia (NH3), and greenhouse gases (GHG), including nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2). Earthworms and amendments may both affect physico-chemical characteristics that control gas-producing processes, and thus affect NH3 and GHG emissions. Here, we used two-way ANOVA to test the effects of addition of reed straw and combined addition of reed straw and zeolite on NH3 and GHG emissions during pre-composting of duck manure, either with or without a follow-up phase of vermicomposting. Results showed that cumulative N2O, CH4, and CO2 emissions during pre-composting and vermicomposting ranged from 92.8, 5.8, and 260.6 mg kg(-)(1) DM to 274.2, 30.4, and 314.0 mg kg(-1) DM, respectively. Earthworms and amendments significantly decreased N2O and CH4 emissions. Emission of CO2 was not affected by earthworms, but increased in responses to addition of reed straw. Cumulative NH3 emission ranged from 3.0 to 8.1 g kg(-1) DM, and was significantly decreased by reed straw and zeolite addition. In conclusion, combined pre-composting and vermicomposting with reed straw and zeolite addition would be strongly recommended in mitigating emissions of N2O, CH4, and NH3 from duck manure. Moreover, this method also provides nutrient-rich products that can be used as a fertilizer. PMID:24835490

  12. Sustainable reuse of rice residues as feedstocks in vermicomposting for organic fertilizer production.

    PubMed

    Shak, Katrina Pui Yee; Wu, Ta Yeong; Lim, Su Lin; Lee, Chieh Ai

    2014-01-01

    Over the past decade, rice (Oryza sativa or Oryza glaberrima) cultivation has increased in many rice-growing countries due to the increasing export demand and population growth and led to a copious amount of rice residues, consisting mainly of rice straw (RS) and rice husk (RH), being generated during and after harvesting. In this study, Eudrilus eugeniae was used to decompose rice residues alone and rice residues amended with cow dung (CD) for bio-transformation of wastes into organic fertilizer. Generally, the final vermicomposts showed increases in macronutrients, namely, calcium (11.4-34.2%), magnesium (1.3-40.8%), phosphorus (1.2-57.3%), and potassium (1.1-345.6%) and a decrease in C/N ratio (26.8-80.0%) as well as increases in heavy metal content for iron (17-108%), copper (14-120%), and manganese (6-60%) after 60 days of vermicomposting. RS as a feedstock was observed to support healthier growth and reproduction of earthworms as compared to RH, with maximum adult worm biomass of 0.66 g/worm (RS) at 60 days, 31 cocoons (1RS:2CD), and 23 hatchlings (1RS:1CD). Vermicomposting of RS yielded better results than RH among all of the treatments investigated. RS that was mixed with two parts of CD (1RS:2CD) showed the best combination of nutrient results as well as the growth of E. eugeniae. In conclusion, vermicomposting could be used as a green technology to bio-convert rice residues into nutrient-rich organic fertilizers if the residues are mixed with CD in the appropriate ratio. PMID:23900949

  13. Vermicomposting grape marc yields high quality organic biofertiliser and bioactive polyphenols.

    PubMed

    Domínguez, Jorge; Martínez-Cordeiro, Hugo; Álvarez-Casas, Marta; Lores, Marta

    2014-12-01

    Grape is the largest fruit crop in the world, and most (80%) of the harvested fruit is used to make wine. The main by-product of the wine industry is called grape marc, which consists of the stalks, skin, pulp and seeds that remain after pressing the grapes. The aim of this study was to evaluate whether grape marc could be processed by vermicomposting on an industrial scale to yield both a high-quality organic, polyphenol-free fertiliser and grape seeds (as a source of bioactive polyphenols). Vermicomposting reduced the biomass of grape marc substantially (by 58%), mainly as a result of the loss of volatile solids. After 2 weeks, the process yielded a nutrient-rich, microbiologically active and stabilised peat-like material that was easily separated from the seeds by sieving. Although the polyphenol content of the seeds was considerably reduced, this disadvantage was outweighed by the ease of separation of the seeds. Separation of the seeds also eliminated the polyphenol-associated phytotoxicity from the vermicompost. The seeds still contained useful amounts of polyphenols, which could be directly extracted for use in the pharmaceutical, cosmetic and food industries. The procedure described is effective, simple and economical, and could easily be scaled up for industrial application. PMID:25349068

  14. Critical tests for determination of microbiological quality and biological activity in commercial vermicompost samples of different origins.

    PubMed

    Grantina-Ievina, Lelde; Andersone, Una; Berkolde-P?re, Dace; Nikolajeva, Vizma; Ievinsh, Gederts

    2013-12-01

    The aim of the present paper was to show that differences in biological activity among commercially produced vermicompost samples can be found by using a relatively simple test system consisting of microorganism tests on six microbiological media and soilless seedling growth tests with four vegetable crop species. Significant differences in biological properties among analyzed samples were evident both at the level of microbial load as well as plant growth-affecting activity. These differences were mostly manufacturer- and feedstock-associated, but also resulted from storage conditions of vermicompost samples. A mature vermicompost sample that was produced from sewage sludge still contained considerable number of Escherichia coli. Samples from all producers contained several potentially pathogenic fungal species such as Aspergillus fumigatus, Pseudallescheria boidii, Pseudallescheria fimeti, Pseudallescheria minutispora, Scedosporium apiospermum, Scedosporium prolificans, Scopulariopsis brevicaulis, Stachybotrys chartarum, Geotrichum spp., Aphanoascus terreus, and Doratomyces columnaris. In addition, samples from all producers contained plant growth-promoting fungi from the genera Trichoderma and Mortierella. The described system can be useful both for functional studies aiming at understanding of factors affecting quality characteristics of vermicompost preparations and for routine testing of microbiological quality and biological activity of organic waste-derived composts and vermicomposts. PMID:23504062

  15. Impact of compost, vermicompost and biochar on soil fertility, maize yield and soil erosion in Northern Vietnam: A three year mesocosm experiment.

    PubMed

    Doan, Thuy Thu; Henry-des-Tureaux, Thierry; Rumpel, Cornelia; Janeau, Jean-Louis; Jouquet, Pascal

    2015-05-01

    Compost, vermicompost and biochar amendments are thought to improve soil quality and plant yield. However, little is known about their long-term impact on crop yield and the environment in tropical agro-ecosystems. In this study we investigated the effect of organic amendments (buffalo manure, compost and vermicompost) and biochar (applied alone or with vermicompost) on plant yield, soil fertility, soil erosion and water dynamics in a degraded Acrisol in Vietnam. Maize growth and yield, as well as weed growth, were examined for three years in terrestrial mesocosms under natural rainfall. Maize yield and growth showed high inter-annual variability depending on the organic amendment. Vermicompost improved maize growth and yield but its effect was rather small and was only significant when water availability was limited (year 2). This suggests that vermicompost could be a promising substrate for improving the resistance of agrosystems to water stress. When the vermicompost-biochar mixture was applied, further growth and yield improvements were recorded in some cases. When applied alone, biochar had a positive influence on maize yield and growth, thus confirming its interest for improving long-term soil productivity. All organic amendments reduced water runoff, soil detachment and NH4(+) and NO3(-) transfer to water. These effects were more significant with vermicompost than with buffalo manure and compost, highlighting that the beneficial influence of vermicompost is not limited to its influence on plant yield. In addition, this study showed for the first time that the combination of vermicompost and biochar may not only improve plant productivity but also reduce the negative impact of agriculture on water quality. PMID:25659313

  16. Cloning and functional characterization of endo-?-1,4-glucanase gene from metagenomic library of vermicompost.

    PubMed

    Yasir, Muhammad; Khan, Haji; Azam, Syed Sikander; Telke, Amar; Kim, Seon Won; Chung, Young Ryun

    2013-06-01

    In the vermicomposting of paper mill sludge, the activity of earthworms is very dependent on dietetic polysaccharides including cellulose as energy sources. Most of these polymers are degraded by the host microbiota and considered potentially important source for cellulolytic enzymes. In the present study, a metagenomic library was constructed from vermicompost (VC) prepared with paper mill sludge and dairy sludge (fresh sludge, FS) and functionally screened for cellulolytic activities. Eighteen cellulase expressing clones were isolated from about 89,000 fosmid clones libraries. A short fragment library was constructed from the most active positive clone (cMGL504) and one open reading frame (ORF) of 1,092 bp encoding an endo-?-1,4-glucanase was indentified which showed 88% similarity with Cellvibrio mixtus cellulase A gene. The endo-?-1,4-glucanase cmgl504 gene was overexpressed in Escherichia coli. The purified recombinant cmgl504 cellulase displayed activities at a broad range of temperature (25-55°C) and pH (5.5-8.5). The enzyme degraded carboxymethyl cellulose (CMC) with 15.4 U, while having low activity against avicel. No detectable activity was found for xylan and laminarin. The enzyme activity was stimulated by potassium chloride. The deduced protein and three-dimensional structure of metagenome-derived cellulase cmgl504 possessed all features, including general architecture, signature motifs, and N-terminal signal peptide, followed by the catalytic domain of cellulase belonging to glycosyl hydrolase family 5 (GHF5). The cellulases cloned in this work may play important roles in the degradation of celluloses in vermicomposting process and could be exploited for industrial application in future. PMID:23812813

  17. Management of fresh water weeds (macrophytes) by vermicomposting using Eisenia fetida.

    PubMed

    Najar, Ishtiyaq Ahmed; Khan, Anisa B

    2013-09-01

    In the present study, potential of Eisenia fetida to recycle the different types of fresh water weeds (macrophytes) used as substrate in different reactors (Azolla pinnata reactor, Trapa natans reactor, Ceratophyllum demersum reactor, free-floating macrophytes mixture reactor, and submerged macrophytes mixture reactor) during 2 months experiment is investigated. E. fetida showed significant variation in number and weight among the reactors and during the different fortnights (P <0.05) with maximum in A. pinnata reactor (number 343.3?±?10.23 %; weight 98.62?±?4.23 % ) and minimum in submerged macrophytes mixture reactor (number 105?±?5.77 %; weight 41.07?±?3.97 % ). ANOVA showed significant variation in cocoon production (F4?=?15.67, P <0.05) and mean body weight (F4?=?13.49, P <0.05) among different reactors whereas growth rate (F3?=?23.62, P <0.05) and relative growth rate (F3?=?4.91, P <0.05) exhibited significant variation during different fortnights. Reactors showed significant variation (P <0.05) in pH, Electrical conductivity (EC), Organic carbon (OC), Organic nitrogen (ON), and C/N ratio during different fortnights with increase in pH, EC, N, and K whereas decrease in OC and C/N ratio. Hierarchical cluster analysis grouped five substrates (weeds) into three clusters-poor vermicompost substrates, moderate vermicompost substrate, and excellent vermicompost substrate. Two principal components (PCs) have been identified by factor analysis with a cumulative variance of 90.43 %. PC1 accounts for 47.17 % of the total variance represents "reproduction factor" and PC2 explaining 43.26 % variance representing "growth factor." Thus, the nature of macrophyte affects the growth and reproduction pattern of E. fetida among the different reactors, further the addition of A. pinnata in other macrophytes reactors can improve their recycling by E. fetida. PMID:23589265

  18. Attenuation of veterinary antibiotics in full-scale vermicomposting of swine manure via the housefly larvae (Musca domestica)

    NASA Astrophysics Data System (ADS)

    Zhang, Zhijian; Shen, Jianguo; Wang, Hang; Liu, Meng; Wu, Longhua; Ping, Fan; He, Qiang; Li, Hongyi; Zheng, Changfeng; Xu, Xinhua

    2014-10-01

    Animal waste from concentrated swine farms is widely considered to be a source of environmental pollution, and the introduction of veterinary antibiotics in animal manure to ecosystems is rapidly becoming a major public health concern. A housefly larvae (Musca domestica) vermireactor has been increasingly adopted for swine manure value-added bioconversion and pollution control, but few studies have investigated its efficiency on antibiotic attenuation during manure vermicomposting. In this study we explored the capacity and related attenuation mechanisms of antibiotic degradation and its linkage with waste reduction by field sampling during a typical cycle (6 days) of full-scale larvae manure vermicomposting. Nine antibiotics were dramatically removed during the 6-day vermicomposting process, including tetracyclines, sulfonamides, and fluoroquinolones. Of these, oxytetracycline and ciprofloxacin exhibited the greater reduction rate of 23.8 and 32.9 mg m-2, respectively. Environmental temperature, pH, and total phosphorus were negatively linked to the level of residual antibiotics, while organic matter, total Kjeldahl nitrogen, microbial respiration intensity, and moisture exhibited a positive effect. Pyrosequencing data revealed that the dominant phyla related to Firmicutes, Bacteroidetes, and Proteobacteria accelerated manure biodegradation likely through enzyme catalytic reactions, which may enhance antibiotic attenuation during vermicomposting.

  19. Vermicomposting of coffee pulp using the earthworm Eisenia fetida: Effects on C and N contents and the availability of nutrients

    Microsoft Academic Search

    F. H. Orozco; J. Cegarra; L. M. Trujillo; A. Roig

    1996-01-01

    In Colombia, more than 1 million tons of coffee pulp are produced every year. Its transformation into compost by means of turned piles has led to a final product with poor physical and chemical characteristics and vermicomposting has been suggested as an alternative method of transforming these wastes into a useful organic fertilizer. The ability of the earthworm Eisenia fetidato

  20. Vermicomposting of vegetable-market solid waste using Eisenia fetida: Impact of bulking material on earthworm growth and decomposition rate

    Microsoft Academic Search

    Surindra Suthar

    2009-01-01

    Vegetable-market solid waste is produced in millions of tones in urban areas and creates a problem of safe disposal. The aim of this study was to convert vegetable solid waste (VW) amended with wheat straw (WS), cow dung (CD), and biogas slurry (BGS) into vermicompost using earthworm Eisenia fetida. VW was mixed in bulky materials (WS, CD, and BGS) in

  1. Pig manure vermicompost as a component of a horticultural bedding plant medium: effects on physicochemical properties and plant growth

    Microsoft Academic Search

    R. M. Atiyeh; C. A. Edwards; S. Subler; J. D. Metzger

    2001-01-01

    This experiment was designed to characterize the physical, chemical and microbial properties of a standard commercial horticultural, greenhouse container, bedding plant medium (Metro-Mix 360), that had been substituted with a range of increasing concentrations (0%, 5%, 10%, 25%, 50% and 100% by volume) of pig manure vermicompost and to relate these properties to plant growth responses. The growth trials used

  2. Vermicomposting of paper mill solid waste using epigeic earthworm Eudrilus eugeniae.

    PubMed

    Ponmani, S; Udayasoorian, C; Jayabalakrishnan, R M; Kumar, K Vinoth

    2014-07-01

    A 90 day study was conducted to evaluate the efficiency of an exotic earthworm species (Eudrilus eugeniae) for decomposition of different types of organic substrates (mixed liquor suspended solids, cow dung and leaf litter) into valuable vermicompost. Mixed liquor suspended solids (MLSS) and leaf litter (LL) were mixed with cow dung (CD) in eight different ratios with three replicates for each treatment. All vermibeds expressed a significant decrease in pH, organic carbon, C:N ratio and an increase in total nitrogen, phosphorus and potash. Overall, earthworms could maximize decomposition and mineralization efficiency in bedding with lower proportions of MLSS. Maximum value for earth worm zoo mass and higher concentration of nutrient content was observed in CD + MLSS + LL in 1:1:2 ratios. Earthworm mortality tended to increase with increasing proportion of MLSS and maximum mortality in E. eugeniae was recorded for MLSS treatment alone. Results indicate that vermicomposting might be useful for managing the energy and nutrient of MLSS on a low-input basis. Products of this process can be used for sustainable land restoration practices. PMID:25004743

  3. Las igualas médicas frente al seguro social (República Dominicana)

    Microsoft Academic Search

    Isidoro Santana

    1997-01-01

    Los servicios médicos del seguro social y las igualas médicas privadas son sistemas de provisión de servicios prepagados de salud. El primero se organiza bajo la modalidad de producción estatal, con una gestión centralizada, cotizaciones obligatorias y sin posibilidad de elección del proveedor por parte del usuario. No obstante, el segundo se trata de entidades privadas, gestión descentralizada, regidas por

  4. [Organic waste treatment by earthworm vermicomposting and larvae bioconversion: review and perspective].

    PubMed

    Zhang, Zhi-jian; Liu, Meng; Zhu, Jun

    2013-05-01

    There is a growing attention on the environmental pollution and loss of potential regeneration of resources due to the poor handling of organic wastes, while earthworm vermicomposting and larvae bioconversion are well-known as two promising biotechnologies for sustainable wastes treatments, where earthworms or housefly larvae are employed to convert the organic wastes into humus like material, together with value-added worm product. Taken earthworm ( Eisenia foetida) and housefly larvae ( Musca domestica) as model species, this work illustrates fundamental definition and principle, operational process, technical mechanism, main factors, and bio-chemical features of organisms of these two technologies. Integrated with the physical and biochemical mechanisms, processes of biomass conversion, intestinal digestion, enzyme degradation and microflora decomposition are comprehensively reviewed on waste treatments with purposes of waste reduction, value-addition, and stabilization. PMID:23914515

  5. Winery vermicomposts to control the leaching of diuron, imidacloprid and their metabolites: role of dissolved organic carbon content.

    PubMed

    Fernández-Bayo, Jesús D; Nogales, Rogelio; Romero, Esperanza

    2015-01-01

    Soil organic amendment addition is an effective practice in Mediterranean areas due to its associated high agricultural benefits and its potential to reduce the pesticide impact on water resources. However, their metabolites have received scarce attention, even when they may pose more risk than their parent compounds. Two winery vermicomposts obtained from spent grape marc (V1) and the mixture vine shoot-biosolid vinasses (V2) have been investigated as low cost organic amendments to minimize the leaching of diuron, imidacloprid and their metabolites in columns packed with a sandy loam (S1) and a silty-clay loam soil (S2) under steady state flow conditions. In the unamended soil columns, leached amounts of diuron were 75% and 53% in S1 and S2, respectively. Its metabolites (3-(3,4-dichlorophenyl)-1-methylurea, DPMU; and 3,4-dichlorophenylurea, DPU) percolated less than 35% of the total applied amount. The amount of the metabolite 3,4-dichloroaniline (DCA) was 2% and 30% for S1 and S2, respectively. Leaching of imidacloprid was 79% and 96% for S1 and S2, respectively, while its metabolite 6-chloronicotinic acid (CNA) was entirely leached. In the vermicompost-amended columns, the leaching of diuron was reduced 2 to 3-fold. DPMU and DPU were also significantly reduced (more than 6-fold). DCA did not appear in any of the leachates of the amended soil columns. Imidacloprid leaching was reduced 1 to 2-folds in the amended columns. The amendments did not affect the transport of CNA. The dissolved organic carbon (DOC) from the vermicomposts did not enhance pesticide transport throughout the soil in any case. This qualitative study presents these vermicomposts as an effective potential low-cost tool in reducing pesticide and metabolite leaching. The next step would be to test them under more realistic conditions. PMID:25602152

  6. Comparative assessment of heavy metals content during the composting and vermicomposting of Municipal Solid Waste employing Eudrilus eugeniae.

    PubMed

    Soobhany, Nuhaa; Mohee, Romeela; Garg, Vinod Kumar

    2015-05-01

    This study was undertaken to have comparative assessment of heavy metals content during composting and vermicomposting processing of Municipal Solid Waste (MSW). Six scenarios were set up in which three experiments were for composting (controls) denoted as S1 for food waste, S2 for paper waste and S3 for yard waste and the corresponding replicates for vermicomposting processes were S4, S5 and S6. Vermicomposting caused significant reduction in Cd (43.3-73.5%), Cr (11.3-52.8%), Cu (18.9-62.5%), Co (21.4-47.6%), Zn (34.6%) and Ni (19.9-49.6%) compared to composting which showed a progressive increase. Addition of worms did not show any effect on Fe and Mn, most probably from the genesis of organic-bound complexes. The efficacy of utilizing Eudrilus eugeniae was indicated by the high values of bioconcentration factors (BCFs) which were in the order of Cd>Ni>Cu>Co>Cr>Zn and the increase amount of these metals in the earthworms' tissue after the vermicomposting processes. Different values of BCFs were obtained for different heavy metals and this accounted that earthworms exert different metabolic mechanisms. Regression analysis of the reduction percentages (R) in relation to BCF showed that RCdtot.S6, RCrtot.S5 and RCutot.S6 were significantly correlated with BCFCd.S6, BCFCr.S5 and BCFCu.S6 respectively. Thus, in comparison to simple composting processes, data analysis suggested the feasibility of inoculating E. eugeniae to MSW in order to mitigate the content of toxic heavy metals. PMID:25708402

  7. Doan Thu et al. published in European Journal of Soil Biology The earthworm species Metaphire posthuma modulates the effect of organic

    E-print Network

    Paris-Sud XI, Université de

    Doan Thu et al. published in European Journal of Soil Biology 1 The earthworm species Metaphire of the endogeic earthworm Metaphire posthuma. This experiment was carried out for 15 months with a maize in soils amended with compost and vermicompost. Earthworms negatively influenced soil microbial properties

  8. Short-term effect of vermicompost application on biological properties of an alkaline soil with high lime content from Mediterranean region of Turkey.

    PubMed

    Uz, Ilker; Tavali, Ismail Emrah

    2014-01-01

    This study was conducted to investigate direct short-term impact of vermicompost on some soil biological properties by monitoring changes after addition of vermicompost as compared to farmyard manure in an alkaline soil with high lime content from semiarid Mediterranean region of Turkey. For this purpose, mixtures of soil and organic fertilizers in different doses were incubated under greenhouse condition. Soil samples collected in regular intervals were analyzed for biological parameters including dehydrogenase, ?-glucosidase, urease, alkaline phosphatase activities, and total number of aerobic mesophilic bacteria. Even though soil dehydrogenase activity appeared to be dose-independent based on overall evaluation, organic amendments were found to elevate dehydrogenase activity when sampling periods are evaluated individually. ?-glucosidase, urease, alkaline phosphatase activity, and aerobic mesophilic bacterial numbers in vermicompost treatments fluctuated but remained significantly above the control. A slight but statistically significant difference was detected between organic amendments in terms of urease activity. Vermicompost appeared to more significantly increase bacterial number in soil. Clearly, vermicompost has a potential to be used as an alternative to farmyard manure to improve and maintain soil biological activity in alkaline calcareous soils from the Mediterranean region of Turkey. Further studies are needed to assess its full potential for these soils. PMID:25254238

  9. Short-Term Effect of Vermicompost Application on Biological Properties of an Alkaline Soil with High Lime Content from Mediterranean Region of Turkey

    PubMed Central

    Uz, Ilker; Tavali, Ismail Emrah

    2014-01-01

    This study was conducted to investigate direct short-term impact of vermicompost on some soil biological properties by monitoring changes after addition of vermicompost as compared to farmyard manure in an alkaline soil with high lime content from semiarid Mediterranean region of Turkey. For this purpose, mixtures of soil and organic fertilizers in different doses were incubated under greenhouse condition. Soil samples collected in regular intervals were analyzed for biological parameters including dehydrogenase, ?-glucosidase, urease, alkaline phosphatase activities, and total number of aerobic mesophilic bacteria. Even though soil dehydrogenase activity appeared to be dose-independent based on overall evaluation, organic amendments were found to elevate dehydrogenase activity when sampling periods are evaluated individually. ?-glucosidase, urease, alkaline phosphatase activity, and aerobic mesophilic bacterial numbers in vermicompost treatments fluctuated but remained significantly above the control. A slight but statistically significant difference was detected between organic amendments in terms of urease activity. Vermicompost appeared to more significantly increase bacterial number in soil. Clearly, vermicompost has a potential to be used as an alternative to farmyard manure to improve and maintain soil biological activity in alkaline calcareous soils from the Mediterranean region of Turkey. Further studies are needed to assess its full potential for these soils. PMID:25254238

  10. Solid waste management of temple floral offerings by vermicomposting using Eisenia fetida

    SciTech Connect

    Singh, Akanksha, E-mail: bhuaks29@gmail.com [Department of Botany, Banaras Hindu University, Varanasi 221 005 (India); Jain, Akansha, E-mail: akansha007@rediffmail.com [Department of Botany, Banaras Hindu University, Varanasi 221 005 (India); Sarma, Birinchi K., E-mail: birinchi_ks@yahoo.com [Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221 005 (India); Abhilash, P.C., E-mail: pca.iesd@bhu.ac.in [Institute for Environment and Sustainable Development, Banaras Hindu University, Varanasi 221 005 (India); Singh, Harikesh B., E-mail: hbs1@rediffmail.com [Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221 005 (India)

    2013-05-15

    Highlights: ? Effective management of temple floral offerings using E. fetida. ? Physico-chemical properties in TW VC were better especially EC, C/N, C/P and TK. ? TW VC as plant growth promoter at much lower application rates than KW and FYW VC. - Abstract: Recycling of temple waste (TW) mainly comprising of floral offerings was done through vermitechnology using Eisenia fetida and its impact on seed germination and plant growth parameters was studied by comparing with kitchen waste (KW) and farmyard waste (FYW) vermicompost (VC). The worm biomass was found to be maximum in TW VC compared to KW and FYW VCs at both 40 and 120 days old VCs. Physico-chemical analysis of worm-worked substrates showed better results in TW VC especially in terms of electrical conductivity, C/N, C/P and TK. 10% TW VC–water extract (VCE) showed stimulatory effect on germination percentage of chickpea seeds while KW and FYW VCE proved effective at higher concentration. Variation in growth parameters was also observed with change in the VC–soil ratio and TW VC showed enhanced shoot length, root length, number of secondary roots and total biomass at 12.5% VC compared to KW and FYW VC.

  11. Heavy metal and nutrient changes during vermicomposting animal manure spiked with mushroom residues.

    PubMed

    Song, Xiuchao; Liu, Manqiang; Wu, Di; Qi, Lin; Ye, Chenglong; Jiao, Jiaguo; Hu, Feng

    2014-11-01

    A pilot-scale trial of four months was conducted to investigate the responses of heavy metal and nutrient to composting animal manure spiked with mushroom residues with and without earthworms. Results showed that earthworm activities accelerated organic matter mineralization (e.g. reduction in C/N ratio, increase in total concentrations of N, P, K) and humification (e.g. increase in humic acid concentration, humification ratio and humification index). Despite composting increased total heavy metal (i.e. As, Pb, Cu, Zn) concentrations irrespective of earthworm, the availability of heavy metals extracted by DTPA significantly (P<0.05) decreased particularly in treatments with earthworms introduced. The shift from available to unavailable fractions of heavy metals was either due to earthworm bioaccumulation, as indicated by total heavy metal concentrations being higher in earthworm tissues, or due to the formation of stable metal-humus complexes as indicated by the promotion of humification. Our results suggest that vermicomposting process could magnify the nutrient quality but relieve the heavy metals risk of agricultural organic wastes. PMID:25128918

  12. Solid waste management of temple floral offerings by vermicomposting using Eisenia fetida.

    PubMed

    Singh, Akanksha; Jain, Akansha; Sarma, Birinchi K; Abhilash, P C; Singh, Harikesh B

    2013-05-01

    Recycling of temple waste (TW) mainly comprising of floral offerings was done through vermitechnology using Eisenia fetida and its impact on seed germination and plant growth parameters was studied by comparing with kitchen waste (KW) and farmyard waste (FYW) vermicompost (VC). The worm biomass was found to be maximum in TW VC compared to KW and FYW VCs at both 40 and 120days old VCs. Physico-chemical analysis of worm-worked substrates showed better results in TW VC especially in terms of electrical conductivity, C/N, C/P and TK. 10% TW VC-water extract (VCE) showed stimulatory effect on germination percentage of chickpea seeds while KW and FYW VCE proved effective at higher concentration. Variation in growth parameters was also observed with change in the VC-soil ratio and TW VC showed enhanced shoot length, root length, number of secondary roots and total biomass at 12.5% VC compared to KW and FYW VC. PMID:23481343

  13. Phosphate solubilizing ability of Emericella nidulans strain V1 isolated from vermicompost.

    PubMed

    Bhattacharya, Satya Sunder; Barman, Soma; Ghosh, Ranjan; Duary, Raj Kumar; Goswami, Linee; Mandal, Narayan C

    2013-10-01

    Phosphorus is one of the key factors that regulate soil fertility. Its deficiencies in soil are largely replenished by chemical fertilizers. The present study was aimed to isolate efficient phosphate solubilizing fungal strains from Eisenia fetida vermicompost. Out of total 30 fungal strains the most efficient phosphate solubilizing one was Emericella (Aspergillus) nidulans V1 (MTCC 11044), identified by custom sequencing of beta-tubulin gene and BLAST analysis. This strain solubilized 13 to 36% phosphate from four different rock phosphates. After three days of incubation of isolated culture with black Mussorie phosphate rock, the highest percentage of phosphate solubilization was 35.5 +/- 1.01 with a pH drop of 4.2 +/- 0.09. Kinetics of solubilization and acid production showed a linear relationship until day five of incubation. Interestingly, from zero to tenth day of incubation, solubility of soil phosphate increased gradually from 4.31 +/- 1.57 to 13.65 +/- 1.82 (mg kg(-1)) recording a maximum of 21.23 +/- 0.54 on day 45 in respect of the V1 isolate. Further, enhanced phosphorus uptake by Phaseolus plants with significant pod yield due to soil inoculation of Emericella nidulans V1 (MTCC 11044), demonstrated its prospect as an effective biofertilizer for plant growth. PMID:24266109

  14. Plasmid transfer between introduced and indigenous bacteria in leaf litter, soil and vermicompost as affected by soil invertebrates

    Microsoft Academic Search

    B. A. Byzov; H. Claus; E. B. Tretyakova; N. F. Ryabchenko; I. N. Mozgovaya; D. G. Zvyagintsev; Z. Filip

    1999-01-01

    Plasmid transfer between introduced strains of Pseudomonas stutzeri JM302 (pLV1013), Pseudomonas putida PAW340 (pLV1017), Pseudomonas aeruginosa PAO5 (RP4), and Enterobacter cloacae MF10 (RP4), all of them harbouring genetically modified or naturally occurring plasmids and bacteria indigenous to oak leaf\\u000a litter, soddy-podzolic soil or vermicompost was monitored using non-sterile laboratory microcosms inhabited by the millipede\\u000a Pachyiulus flavipes, the woodlouse Armadillidium vulgare,

  15. CH4 and N2O from mechanically turned windrow and vermicomposting systems following in-vessel pre-treatment.

    PubMed

    Hobson, A M; Frederickson, J; Dise, N B

    2005-01-01

    Methane (CH4) and nitrous oxide (N2O) are included in the six greenhouse gases listed in the Kyoto protocol that require emission reduction. To meet reduced emission targets, governments need to first quantify their contribution to global warming. Composting has been identified as an important source of CH4 and N2O. With increasing divergence of biodegradable waste from landfill into the composting sector, it is important to quantify emissions of CH4 and N2O from all forms of composting and from all stages. This study focuses on the final phase of a two stage composting process and compares the generation and emission of CH4 and N2O associated with two differing composting methods: mechanically turned windrow and vermicomposting. The first stage was in-vessel pre-treatment. Source-segregated household waste was first pre-composted for seven days using an in-vessel system. The second stage of composting involved forming half of the pre-composted material into a windrow and applying half to vermicomposting beds. The duration of this stage was 85 days and CH4 and N2O emissions were monitored throughout for both systems. Waste samples were regularly subjected to respirometry analysis and both processes were found to be equally effective at stabilising the organic matter content. The mechanically turned windrow system was characterised by emissions of CH4 and to a much lesser extent N2O. However, the vermicomposting system emitted significant fluxes of N2O and only trace amounts of CH4. In-vessel pre-treatment removed considerable amounts of available C and N prior to the second stage of composting. This had the effect of reducing emissions of CH4 and N2O from the second stage compared to emissions from fresh waste found in other studies. The characteristics of each of the two composting processes are discussed in detail. Very different mechanisms for emission of CH4 and N2O are proposed for each system. For the windrow system, development of anaerobic zones were thought to be responsible for CH4 release. High N2O emission rates from vermicomposting were ascribed to strongly nitrifying conditions in the processing beds combined with the presence of de-nitrifying bacteria within the worm gut. PMID:15869976

  16. Organic matter transformations in lignocellulosic waste products composted or vermicomposted ( eisenia fetida andrei): Chemical analysis and 13C CPMAS NMR spectroscopy

    Microsoft Academic Search

    M. Vinceslas-Akpa; M. Loquet

    1997-01-01

    Lignocellulosic wastes (of maple) were composted and vermicomposted for 10 months under controlled conditions. Chemical and 13C CPMAS NMR spectroscopic analyses were made to characterize the transformations of the organic matter. At first, the total organic matter and carbon mass underwent a relatively rapid decrease. There was a concomitant decomposition of polysaccharides including cellulose. The degradation of aromatic structures and

  17. Vermicomposting of toxic weed--Lantana camara biomass: chemical and microbial properties changes and assessment of toxicity of end product using seed bioassay.

    PubMed

    Suthar, Surindra; Sharma, Priyanka

    2013-09-01

    This work illustrates the results of vermicomposting trials of noxious weed - Lantana camara (LL) leaf litter spiked with cow dung (CD) in different ratios (0%, 20%, 40%, 60% and 80%) using Eisenia fetida. A total of five treatments were established and changes in chemical and microbial properties of vermibeds have been observed for 60 days. In all treatments, a decrease in pH (19.5-30.7%), total organic carbon (TOC) (12-23%) and C:N ratio (25-35%), but increase in ash content (16-40%), total N(N(tot)) (11-32%), available phosphorous (P(avail)) (445-629%), exchangeable potassium (K(exch)) (63-156%) exchangeable calcium (Ca(exch)) (67-94%),and N-NO3(-) (164-499%) was recorded. Vermibeds with 40-60% LL (T2 and T3) showed better mineralization rate. The number of fungi, bacteria and actinomycetes showed 0.33-1.67-fold, 0.72-2.33-fold and 2.03-2.99-fold increase, respectively after vermicomposting process. The germination index (GI) was between 47% and 83% in all vermicomposts as indicated by seed bioassay test. Results thus suggested that Lantana may be a potential source for vermicompost production for sustainable agriculture. PMID:23796668

  18. Organic amendment based on vermicompost and compost: differences on soil properties and maize yield.

    PubMed

    Tejada, Manuel; Benítez, Concepción

    2011-11-01

    The objective of the present study was to study the effect of two vermicomposts [animal (VCD) and vegetal origin (VGF)] and a cotton gin compost (C) at rates of 1780 and 3560?kg fresh organic matter?ha(-1) for 3 years on an Typic Xerofluvent located near Seville (Spain) on soil biological properties, nutrition (leaf N, P and K concentration, pigments and soluble carbohydrate concentrations) and yield parameters of maize (Zea mays cv. Tundra) crop. All organic waste materials had a positive effect on the soil biological properties, plant nutrition and crop yield parameters, although at the end of the experimental period and at the high organic matter rate, the soil microbial biomass and dehydrogenase, urease, ?-glucosidase, phosphatase and arylsulfatase activities increased more significantly in the VCD-amended soils (86.4, 85.8, 94.5, 99.3, 70.1 and 63.8%, respectively) respect to the control soil, followed by VGF-amended soils (84.8, 80.6, 92.7, 99.1, 68.3 and 61.6%, respectively) and CC-amended soils (80.5, 75.9, 89.7, 99, 65.7 and 59.9%, respectively). Leaf N, P and K contents and pigments and soluble carbohydrate contents were highest in VCD-amended soils, followed by VGF and CC treatments. Compared with the control soil, the application of VCD in soils at high doses increased the crop yield parameters, followed by VGF and CC treatments. This may have been due to a greater labile fraction of organic matter in the VCD than the VGF and CC, respectively. PMID:20921058

  19. Experimental co-digestion of corn stalk and vermicompost to improve biogas production

    SciTech Connect

    Chen Guangyin [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Zheng Zheng, E-mail: zzhenghj@fudan.edu.c [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Department of Environmental Science and Engineering, Fudan University, Shanghai 200433 (China); Yang Shiguan [National Engineering Laboratory of Biomass Power Generation Equipment, School of Renewable Energy, North China Electric Power University, Beijing 102206 (China); Fang Caixia; Zou Xingxing; Luo Yan [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2010-10-15

    Anaerobic co-digestion of corn stalk and vermicompost (VC) as well as mono-digestion of corn stalk were investigated. Batch mono-digestion experiments were performed at 35 {+-} 1 {sup o}C and initial total solid loading (TSL) ranged from 1.2% to 6.0%. Batch co-digestion experiments were performed at 35 {+-} 1 {sup o}C and initial TSL of 6% with VC proportions ranged from 20% to 80% of total solid (TS). For mono-digestion of corn stalk, a maximum methane yield of 217.60 {+-} 13.87 mL/g TS{sub added} was obtained at initial TSL of 4.8%, and acidification was found at initial TSL of 6.0% with the lowest pH value of 5.10 on day 4. Co-digestion improved the methane yields by 4.42-58.61% via enhancing volatile fatty acids (VFAs) concentration and pH value compared with mono-digestion of corn stalk. The maximum biogas yield of 410.30 {+-} 11.01 mL/g TS{sub added} and methane yield of 259.35 {+-} 13.85 mL/g TS{sub added} were obtained for 40% VC addition. Structure analysis by X-ray diffractometry (XRD) showed that the lowest crystallinity of 35.04 of digested corn stalk was obtained from co-digestion with 40% VC, which decreased 29.4% compared to 49.6 obtained from un-treated corn stalk. It is concluded that co-digestion with VC is beneficial for improving biodigestibility and methane yield from corn stalk.

  20. Treatment and biotransformation of highly polluted agro-industrial wastewater from a palm oil mill into vermicompost using earthworms.

    PubMed

    Lim, Su Lin; Wu, Ta Yeong; Clarke, Charles

    2014-01-22

    In this laboratory-scale study, earthworms were introduced as biodegraders of palm oil mill effluent (POME), which is a wastewater produced from the wet process of palm oil milling. POME was absorbed into amendments (soil or rice straw) in different ratios as feedstocks for the earthworm, Eudrilus eugeniae. The presence of earthworms led to significant increases in pH, electrical conductivity, and nutrient content but decreases in the C/N ratio (0.687-75.8%), soluble chemical oxygen demand (19.7-87.9%), and volatile solids (0.687-52.7%). However, earthworm growth was reduced in all treatments by the end of the treatment process. Rice straw was a better amendment/absorbent relative to soil, with a higher nutrient content and greater reduction in soluble chemical oxygen demand with a lower C/N ratio in the vermicompost. Among all treatments investigated, the treatment with 1 part rice straw and 3 parts POME (w/v) (RS1:3) produced the best quality vermicompost with high nutritional status. PMID:24372356

  1. Tracking the composition and transformation of humic and fulvic acids during vermicomposting of sewage sludge by elemental analysis and fluorescence excitation-emission matrix.

    PubMed

    Zhang, Jie; Lv, Baoyi; Xing, Meiyan; Yang, Jian

    2015-05-01

    Sewage sludge (T1) and the mixture of sewage sludge and cattle dung (T2) were vermicomposted with Eisenia fetida, respectively. The transformation of humic acid (HA) and fulvic acid (FA) extracted from these two treatments were evaluated by a series of chemical and spectroscopic methods. Results indicated that the vermicomposting decreased pH, TOC, and C/N ratio, and increased EC, total extractable C, and HA contents. The FA content in treatment T1 was increased significantly, and only slight increasing was observed in treatment T2. Moreover, vermicomposting decreased H content, C/N ratio, proteinaceous and carbohydrates components, and increased the N content, C/H ratio, aromatic compounds and polycondensation structures in HA and FA. In addition, fluorescence spectra and fluorescence regional integration indicated that protein-like groups were degraded and HA compounds were formed. Furthermore, the addition of cattle dung enhanced the humification process and improved the HA quality in spite of no significant effect on the FA. PMID:25736580

  2. CH{sub 4} and N{sub 2}O from mechanically turned windrow and vermicomposting systems following in-vessel pre-treatment

    SciTech Connect

    Hobson, A.M. [Department of Earth Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)]. E-mail: a.m.hobson@open.ac.uk; Frederickson, J. [Integrated Waste Systems, Faculty of Technology, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Dise, N.B. [Department of Earth Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Integrated Waste Systems, Faculty of Technology, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2005-07-01

    Methane (CH{sub 4}) and nitrous oxide (N{sub 2}O) are included in the six greenhouse gases listed in the Kyoto protocol that require emission reduction. To meet reduced emission targets, governments need to first quantify their contribution to global warming. Composting has been identified as an important source of CH{sub 4} and N{sub 2}O. With increasing divergence of biodegradable waste from landfill into the composting sector, it is important to quantify emissions of CH{sub 4} and N{sub 2}O from all forms of composting and from all stages. This study focuses on the final phase of a two stage composting process and compares the generation and emission of CH{sub 4} and N{sub 2}O associated with two differing composting methods: mechanically turned windrow and vermicomposting. The first stage was in-vessel pre-treatment. Source-segregated household waste was first pre-composted for seven days using an in-vessel system. The second stage of composting involved forming half of the pre-composted material into a windrow and applying half to vermicomposting beds. The duration of this stage was 85 days and CH{sub 4} and N{sub 2}O emissions were monitored throughout for both systems. Waste samples were regularly subjected to respirometry analysis and both processes were found to be equally effective at stabilising the organic matter content. The mechanically turned windrow system was characterised by emissions of CH{sub 4} and to a much lesser extent N{sub 2}O. However, the vermicomposting system emitted significant fluxes of N{sub 2}O and only trace amounts of CH{sub 4}. In-vessel pre-treatment removed considerable amounts of available C and N prior to the second stage of composting. This had the effect of reducing emissions of CH{sub 4} and N{sub 2}O from the second stage compared to emissions from fresh waste found in other studies. The characteristics of each of the two composting processes are discussed in detail. Very different mechanisms for emission of CH{sub 4} and N{sub 2}O are proposed for each system. For the windrow system, development of anaerobic zones were thought to be responsible for CH{sub 4} release. High N{sub 2}O emission rates from vermicomposting were ascribed to strongly nitrifying conditions in the processing beds combined with the presence of de-nitrifying bacteria within the worm gut.

  3. CARACTERIZACIÓN QUÍMICA Y FÍSICA DE COMPOST DE LOMBRICES ELABORADOS A PARTIR DE RESIDUOS ORGÁNICOS PUROS Y COMBINADOS1 Vermicompost chemical and physical characterization from raw and mixed organic wastes

    Microsoft Academic Search

    Alicia E. Castillo; Silvio H. Quarín; María C. Iglesias

    The purpose of this experiment was the chemical and physical characterization of some vermicomposts and their most suitable mixture in yield and quality. The experiment design used was complete randomized block with five treatment and five replications: T1 (100% cattle feedlot manure E); T2 (100% kitchen wastes DC); T3 (75% E and 25% DC); T4 (50% E and 50% DC);

  4. Evaluation of Streptomyces strains isolated from herbal vermicompost for their plant growth-promotion traits in rice.

    PubMed

    Gopalakrishnan, Subramaniam; Vadlamudi, Srinivas; Bandikinda, Prakash; Sathya, Arumugam; Vijayabharathi, Rajendran; Rupela, Om; Kudapa, Himabindu; Katta, Krishnamohan; Varshney, Rajeev Kumar

    2014-01-20

    Six actinomycetes, CAI-13, CAI-85, CAI-93, CAI-140, CAI-155 and KAI-180, isolated from six different herbal vermi-composts were characterized for in vitro plant growth-promoting (PGP) properties and further evaluated in the field for PGP activity in rice. Of the six actinomycetes, CAI-13, CAI-85, CAI-93, CAI-140 and CAI-155 produced siderophores; CAI-13, CAI-93, CAI-155 and KAI-180 produced chitinase; CAI-13, CAI-140, CAI-155 and KAI-180 produced lipase; CAI-13, CAI-93, CAI-155 and KAI-180 produced protease; and CAI-13, CAI-85, CAI-140 and CAI-155 produced ß-1-3-glucanase whereas all the six actinomycetes produced cellulase, hydrocyanic acid and indole acetic acid (IAA). The actinomycetes were able to grow in NaCl concentrations of up to 8%, at pH values between 7 and 11, temperatures between 20 and 40 °C and compatible with fungicide bavistin at field application levels. In the rice field, the actinomycetes significantly enhanced tiller numbers, panicle numbers, filled grain numbers and weight, stover yield, grain yield, total dry matter, root length, volume and dry weight over the un-inoculated control. In the rhizosphere, the actinomycetes also significantly enhanced total nitrogen, available phosphorous, % organic carbon, microbial biomass carbon and nitrogen and dehydrogenase activity over the un-inoculated control. Sequences of 16S rDNA gene of the actinomycetes matched with different Streptomyces species in BLAST analysis. Of the six actinomycetes, CAI-85 and CAI-93 were found superior over other actinomycetes in terms of PGP properties, root development and crop productivity. qRT-PCR analysis on selected plant growth promoting genes of actinomycetes revealed the up-regulation of IAA genes only in CAI-85 and CAI-93. PMID:24113511

  5. Cómo hacer frente al cáncer: cuidados médicos de apoyo y cuidados paliativos

    Cancer.gov

    Formas de controlar los efectos físicos y psicológicos del cáncer y del tratamiento en los pacientes y sus familias, así como los efectos en la calidad de vida. También se incluye información sobre servicios de salud, ayuda económica y seguro médico.

  6. A luta pela reduo da jornada de trabalho tem vrias frentes no movimento dos

    E-print Network

    Floeter, Sergio Ricardo

    A luta pela redução da jornada de trabalho tem várias frentes no movimento dos trabalhadores política e histórica, uma "bandeira de luta" de muitos trabalhadores/as em nível nacional e internacional

  7. Exploración de Actitudes Masculinas en relación al Rol Femenino a través de Metodología Proyectiva

    Microsoft Academic Search

    Elisabeth Wenk; Armando Ortiz; Andrea Urrea

    Resumen El presente artículo da a conocer el estudio exploratorio realizado en estudiantes universitarios de sexo masculino provenientes de diferentes dominios de conocimiento (Humanista, Científico y Artístico), orientado a reconocer actitudes frente al rol femenino. Para ello, se estructuraron -en base al reconocimiento efectuado a través de una amplia revisión histórica, de ideas arquetípicas y recurrentes respecto a lo femenino-

  8. Development of a flow system for the determination of cadmium in fuel alcohol using vermicompost as biosorbent and flame atomic absorption spectrometry.

    PubMed

    Bianchin, Joyce Nunes; Martendal, Edmar; Mior, Renata; Alves, Vanessa Nunes; Araújo, Cleide Sandra Tavares; Coelho, Nívia Maria Melo; Carasek, Eduardo

    2009-04-30

    In this study a method for the determination of cadmium in fuel alcohol using solid-phase extraction with a flow injection analysis system and detection by flame atomic absorption spectrometry was developed. The sorbent material used was a vermicompost commonly used as a garden fertilizer. The chemical and flow variables of the on-line preconcentration system were optimized by means of a full factorial design. The selected factors were: sorbent mass, sample pH, buffer concentration and sample flow rate. The optimum extraction conditions were obtained using sample pH in the range of 7.3-8.3 buffered with tris(hydroxymethyl)aminomethane at 50 mmol L(-1), a sample flow rate of 4.5 mL min(-1) and 160 mg of sorbent mass. With the optimized conditions, the preconcentration factor, limit of detection and sample throughput were estimated as 32 (for preconcentration of 10 mL sample), 1.7 microg L(-1) and 20 samples per hour, respectively. The analytical curve was linear from 5 up to at least 50 microg L(-1), with a correlation coefficient of 0.998 and a relative standard deviation of 2.4% (35 microg L(-1), n=7). The developed method was successfully applied to spiked fuel alcohol, and accuracy was assessed through recovery tests, with recovery ranging from 94% to 100%. PMID:19203591

  9. ALS Association

    MedlinePLUS

    ... help fight ALS. Read More » Walk to Defeat ALS® Season Starts Now is the time to put ... Therapy Month Read More » The Leader in Global ALS Research The ALS Association has committed $99 million ...

  10. Variables explicativas de la ansiedad frente a las matemáticas: un estudio de una muestra de 6º de primaria

    Microsoft Academic Search

    Begoña Tejedor; María Auxiliadora Santos; Javier García-Orza; Patricia Carratalà; Marta Navas

    2009-01-01

    En el presente artículo se aborda el estudio de la ansiedad frente a las matemáticas en un grupo de 55 alumnos de sexto de primaria. Se analiza la correlación de esta variable con el rendimiento en matemáticas, con la ansiedad estado y la ansiedad rasgo, con el género y con la representación que los niños se hacen sobre sus habilidades

  11. ALS - resources

    MedlinePLUS

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association - http://mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) ...

  12. Initial Symptoms of ALS

    MedlinePLUS

    Home About ALS About Us Our Research In Your Community Advocate Help fight ALS Donate About ALS What is ALS? Facts You Should Know Who does ALS affect? Diagnosing ALS Symptoms Forms of ALS Genetic ...

  13. Al Composites

    NASA Astrophysics Data System (ADS)

    Chandanayaka, Tharaka; Azarmi, Fardad

    2014-05-01

    In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 ?m were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

  14. Analysis of phytohormones in vermicompost using a novel combinative sample preparation strategy of ultrasound-assisted extraction and solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry.

    PubMed

    Zhang, Hong; Tan, Swee Ngin; Teo, Chee How; Yew, Yan Ru; Ge, Liya; Chen, Xin; Yong, Jean Wan Hong

    2015-07-01

    Vermicompost (VC), a widely used premium organic fertilizer, is the by-product of symbiotic interactions between earthworms and microorganisms living within them. It has been postulated that phytohormones are plausible "magic compounds" in VC that are responsible for making them such good fertilizers. Thus, a novel approach involving ultrasound-assisted extraction (UAE) and solid-phase extraction (SPE) was developed as a fast and efficient sample preparation method to screen for different classes of phytohormones in VC by liquid chromatography-tandem mass spectrometric (LC-MS/MS) analysis. Nine phytohormones from three different classes, including trans-zeatin (tZ), kinetin (K), N(6)-[2-isopentyl]adenine (iP), N(6)-benzyladenine (BA), N(6)-isopentenyladenosine (iPR), indole-3-acetic acid (IAA), 4-[3-indolyl]butyric acid (IBA), 1-naphthaleneacetic acid (NAA) and (+)-abscisic acid (ABA), were simultaneously screened. The extraction parameters influencing UAE ef?ciency were optimized to provide comparable recovery to the conventional mix-stirring (MSt) method. The optimized UAE method was subsequently applied on the analysis of phytohormones in VC, i.e. phytohormone extract was further pre-concentrated and puri?ed using C18 and MCX SPE cartridges prior to LC-MS/MS analysis. The following phytohormones, namely iP, iPR and IAA, were detected and quantified to be 0.49, 0.53, 79.78ngg(-1), respectively; tZ was found to be below the limit of quantitation. Recoveries of 10.2%, 9.1%, 18.9% and 0.3% for tZ, iP, iPR and IAA were obtained. This is one of the few reported works for the successful detection and quantitation of cytokinins and auxins in VC, that provided the key empirical evidence to explain the growth efficacy of applying VC in promoting plant growth. Additionally, this pioneering work could potentially be applicable for the analysis of other types of organic fertilizers such as composts and activated composted materials awaiting phytohormone analyzes for quality assessment and control. PMID:25882426

  15. [AL amyloidosis].

    PubMed

    Jaccard, A; Desport, E; Mohty, D; Bridoux, F

    2015-02-01

    AL amyloidosis belongs to the group of conformational diseases. It is the most common type of amyloidosis with an estimated 500 new cases per year in France. It is due to a small and usually indolent plasma cell clone which synthesizes an unstable, misfolded monoclonal immunoglobulin light chain that is prone to aggregate and form amyloid fibrils. Non-invasive biopsy such as abdominal fat aspiration or minor salivary gland biopsy should be performed to confirm the diagnosis and if negative, involved tissues have to be examined. Clinical presentation is very diverse, as AL amyloidosis can affect almost any organ or tissue in the body, other than the brain. The kidney is the most frequent organ involved, whereas heart disease characterized by restrictive cardiomyopathy is the most severe. Early diagnosis, before advanced cardiomyopathy, is essential for improving outcome. The association of alkylating agent and high-dose dexamethasone is effective in almost two-thirds of patients. Combinations of proteasome inhibitors, dexamethasone, and alkylating agents achieve high response rates. Close monitoring of clonal and organ response is mandatory to guide therapy changes and duration. New treatments designed to eliminate amyloid deposits are under development. PMID:25194219

  16. Schwartz et al., Tella et al., Foltin et al., Trippenbach et al., Regalado et al., Magnano et al., Levin et al., Hale et al., Cocaine day

    E-print Network

    Massachusetts at Amherst, University of

    ., Levin et al., Hale et al., Cocaine day 7 day dry-out period Session I: Baseline Session II: Fixed 8mg, and 32 mg\\70kg respectively with a 100kg cap. All cocaine self-administration sessions take place at the Yale Center for Clinical Investigations Hospital Research Unit. Detecting Signatures of Cocaine Using

  17. Primary AL Amyloidosis

    MedlinePLUS

    ... be administered in combination with other treatments. REVLIMID (lenalidomide) (CC-5013) is a immunomodulatory drug; a derivative ... AL amyloidosis. Findings from initial trials indicate that lenalidomide can be effective in treating AL amyloidosis. There ...

  18. About ALS: FAQ

    MedlinePLUS

    ... disease deterioration in these mice. Clinical trials are of the utmost importance to investigate if the effects seen in the mouse model are seen in humans with ALS. Another question is whether this exciting result found in a model of familial ALS is applicable to sporadic ALS that ...

  19. Al Dimer Dynamics on Al(111)

    NASA Astrophysics Data System (ADS)

    Bogicevic, Alexander; Hyldgaard, Per; Wahnström, Göran; Lundqvist, Bengt I.

    1998-07-01

    Al dimer dynamics on Al(111) at equilibrium and under compression is studied using first-principles density-functional theory calculations. A smooth potential energy surface provides a long-range attraction between the dimer atoms and leads to a substantial temperature window in which dissociation is frozen and exotic dimer dynamics is observed. Surface relaxations play a prominent role in the uncovering of an unexpected ground state and a new diffusion path. A way of affecting growth by compression is illustrated. The possibility of a metal quantum rotor is addressed and further examined using effective-medium theory calculations.

  20. Bodybuilding als Sinnsystem

    Microsoft Academic Search

    Anne Honer

    \\u000a Bodybuilder sind körperlich stigmatisierte Normabweichler. Sie werden nicht nur als unintelligent, sondern auch gern als exhibitionistisch,\\u000a narzisstisch, monströs, ekelhaft, abscheulich, widerwärtig, abstoßend – und was der emphatischen Belegungen mehr sind – betrachtet.\\u000a Sie gelten als aufgeblasene, angeberische, eitle „Popanze“, die mit ihren Muskeln „überhaupt nichts“ anzufangen wüssten, denen\\u000a bei jeder Dauerbelastung die Luft wegbleibe und die zu allem Überfluss (wegen

  1. Beamte, die sich als \\

    Microsoft Academic Search

    Walter Lippmann

    7 Sicherheitspolitik ist also keineswegs wertneutral. Dies betrifft sowohl das Ziel dieser Politik, als auch die Mittel, deren man sich zum Erreichen dieses Ziels bedient. Werden etwa territoriale Integrität und Souveränitäts- wahrung als Kernwerte nationaler Sicherheit angenommen, ent- spricht dies einer normativen politischen Ausrichtung. Im Vorder- grund steht damit die Bewahrung des bestehenden National- staats und nicht beispielsweise die Bildung

  2. Ventilatory Control in ALS

    PubMed Central

    Nichols, Nicole L.; Van Dyke, J.; Nashold, L.; Satriotomo, I.; Suzuki, M.; Mitchell, G.S.

    2015-01-01

    Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease. ALS selectively causes degeneration in upper and lower (spinal) motor neurons, leading to muscle weakness, paralysis and death by ventilatory failure. Although ventilatory failure is generally the cause of death in ALS, little is known concerning the impact of this disorder on respiratory motor neurons, the consequences of respiratory motor neuron cell death, or the ability of the respiratory control system to “fight back” via mechanisms of compensatory respiratory plasticity. Here we review known effects of ALS on breathing, including possible effects on rhythm generation, respiratory motor neurons, and their target organs: the respiratory muscles. We consider evidence for spontaneous compensatory plasticity, preserving breathing well into disease progression despite dramatic loss of spinal respiratory motor neurons. Finally, we review current and potential therapeutic approaches directed toward preserving the capacity to breathe in ALS patients. PMID:23692930

  3. ALS2 mutations

    PubMed Central

    Schneider, Susanne A.; Carr, Lucinda; Deuschl, Guenther; Hopfner, Franziska; Stamelou, Maria; Wood, Nicholas W.; Bhatia, Kailash P.

    2014-01-01

    Objective: To determine the genetic etiology in 2 consanguineous families who presented a novel phenotype of autosomal recessive juvenile amyotrophic lateral sclerosis associated with generalized dystonia. Methods: A combination of homozygosity mapping and whole-exome sequencing in the first family and Sanger sequencing of candidate genes in the second family were used. Results: Both families were found to have homozygous loss-of-function mutations in the amyotrophic lateral sclerosis 2 (juvenile) (ALS2) gene. Conclusions: We report generalized dystonia and cerebellar signs in association with ALS2-related disease. We suggest that the ALS2 gene should be screened for mutations in patients who present with a similar phenotype. PMID:24562058

  4. Amyotrophic Lateral Sclerosis (ALS)

    MedlinePLUS

    ... with ALS may eventually consider forms of mechanical ventilation (respirators). What is the prognosis? Regardless of the ... the muscles of the respiratory system weaken. Although ventilation support can ease problems with breathing and prolong ...

  5. What Is ALS?

    MedlinePLUS

    ... cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord ... throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their death. When ...

  6. Genetic Testing for ALS

    MedlinePLUS

    ... Share Print Familial Amyotrophic Lateral Sclerosis (FALS) and Genetic Testing By Deborah Hartzfeld, MS, CGC, Certified Genetic ... guarantee a person will develop symptoms of ALS. Genetic Counseling If there is more than one person ...

  7. Leakage current behaviors of Al/ZrO2/Al and Al/YSZ/Al devices

    NASA Astrophysics Data System (ADS)

    Yeh, Tsung-Her; Lin, Ruei-De; Cherng, Bo-Ruei; Cherng, Jyh-Shiarn

    2015-01-01

    The leakage current behaviors of Al/ZrO2/Al and Al/yttria stabilized zirconia (YSZ)/Al devices are investigated for resistive random access memory (RRAM) applications. A silicon oxide layer (450 nm) is first formed on a Si wafer by thermal oxidation. Onto it an Al bottom electrode (270 nm), a ZrO2 or YSZ nano-film (75 nm), and an Al top electrode (270 nm) are sequentially deposited by sputtering. These RRAM devices exhibit ohmic behaviors in the low-field region, while Schottky and Poole–Frenkel emissions take over in the high-field regions. Both the Schottky and trap barrier levels are decreased when monoclinic ZrO2 is replaced by cubic YSZ in the metal/oxide/metal structure. This is attributed not only to the higher symmetry crystal structure and lower binding energy of YSZ, but also to the formation of more oxygen vacancies and their re-distribution associated with yttria doping.

  8. Rapidly solidified NiAl and FeAl

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Crimp, M. A.

    1985-01-01

    Melt spinning was used to produce rapidly solidified ribbons of the B2 intermetallics NiAl and FeAl. Both Fe-40Al and Fe-45Al possessed some bend ductility in the as spun condition. The bend ductility of Fe-40Al, Fe-45Al, and equiatomic NiAl increased with subsequent heat treatment. Heat treatment at approximately 0.85 T (sub m) resulted in significant grain growth in equiatomic FeAl and in all the NiAl compositions. Low bend ductility in both FeAl and NiAl generally coincided with intergranular failure, while increased bend ductility was characterized by increasing amounts of transgranular clevage fracture.

  9. Rapidly solidified NiAl and FeAl

    NASA Technical Reports Server (NTRS)

    Gaydosh, D. J.; Crimp, M. A.

    1984-01-01

    Melt spinning was used to produce rapidly solidified ribbons of the B2 intermetallics NiAl and FeAl. Both Fe-40Al and Fe-45Al possessed some bend ductility in the as spun condition. The bend ductility of Fe-40Al, Fe-45Al, and equiatomic NiAl increased with subsequent heat treatment. Heat treatment at approximately 0.85 T (sub m) resulted in significant grain growth in equiatomic FeAl and in all the NiAl compositions. Low bend ductility in both FeAl and NiAl generally coincided with intergranular failure, while increased bend ductility was characterized by increasing amounts of transgranular cleavage fracture.

  10. Negative ion photodetachment spectroscopy of the Al3O2 , Al3O3 , Al4Ox , Al5Ox (x = 35), Al6O5 , and Al7O5 clusters

    E-print Network

    Neumark, Daniel M.

    Negative ion photodetachment spectroscopy of the Al3O2 , Al3O3 , Al4Ox , Al5Ox (x = 3­5), Al6O5 , and Al7O5 clusters Giovanni Meloni, Michael J. Ferguson and Daniel M. Neumark Department of Chemistry as an Advance Article on the web 9th September 2003 The Al3O2 , Al3O3 , Al4Ox , Al5Ox (x ¼ 3­5), Al6O5 , and Al7

  11. Al Qaeda Training Manual

    NSDL National Science Digital Library

    2001-01-01

    The first resource is a US Department of Justice release of portions of an English translation of the Al Qaeda training manual located by police in Manchester, England during a search of an Al Qaeda member's home. The manual was found in a computer file described as "the military series" related to the "Declaration of Jihad." The cover and excerpts from the 12 chapters can be viewed as a .pdf file. Content of the text includes religious commentary, organizational tactics, guidelines for member selection, techniques for spying, and security measures. The DOJ does not provide the entire document because it does not want to encourage terrorism.

  12. MDA ALS Caregiver's Guide

    MedlinePLUS

    ... cure.” And it’s really hard work. It involves learning about new tasks and equipment, while going through the emotions that arise when a loved one has a progressive, debilitating illness. These pages contain practical and emotional strategies for being an effective caregiver. The MDA ALS ...

  13. Ausbildung als zentrale Aufgabe

    NASA Astrophysics Data System (ADS)

    Krämer, Walter; Schmerbach, Sibylle

    Anders als Lesen und Schreiben zählen Grundkenntnisse in Statistik heute noch nicht zu den Voraussetzungen einer sinnvollen Teilhabe am Sozialgeschehen. Und auch in der akademischen Statistik-Ausbildung gibt es noch einiges zu tun. Das vorliegende Kapitel zeichnet die Geschichte dieser akademischen Ausbildung an deutschen Universitäten nach dem zweiten Weltkrieg nach, stellt aktuelle Defizite vor und weist auf mögliche Verbesserungen hin.

  14. Smith et al Supporting Information

    E-print Network

    Jarvis, Erich D.

    Smith et al 1 Supporting Information for Smith et al. 2006, PLoS Computational Biology 2:e161-hyperpallium apicale; HF-hippocampal formation, and M-mesopallium. #12;Smith et al 2 FigureS2,nolinkswerefoundbetweenelectrodesindifferentbirds,andnolinkswerefoundintothesoundstimulusvariable. CombinedAnalysisofAllBirds'ElectrodesPlusSound #12;Smith et al 3 Analysis of Data from Subsections

  15. El científico frente a la \\

    Microsoft Academic Search

    Andrés H. Reggiani

    The article examines the career and legacy of the French-born Nobel laureate Alexis Carrel (1873-1944) as a paradigmatic case of interwar reactionary modernism and cultural despair. Concerned about the \\

  16. /Al-Si Composite

    NASA Astrophysics Data System (ADS)

    Li, Wei; Chen, Jian; Hu, Yongle; Cong, Li; Sun, YouPing; Yang, JiMing

    2014-08-01

    The cyclic fatigue characteristics of spray-deposited SiCp/Al-Si composite were investigated in comparison with the unreinforced Al-Si alloy. The as-extruded specimens were cyclically deformed with fully reversed loading under a range of total strain amplitudes. The results show that the cyclic response characteristics for the reinforced and unreinforced materials are similar to each other. Both the composite and matrix alloys display cyclic hardening under total strain amplitude of 0.35-0.5%. Otherwise, the composite exhibits higher degree of strain hardening than that of the matrix alloy. Dislocation substructure developed during cyclic deformation was analyzed using transmission electron microscopy. The discrepancy between dislocation substructures obtained from processing compared to its development during cyclic strain loading is thought to give rise to the observed cyclic stress response behavior. Fractographic analysis shows that particle/matrix debonding and particle cracking are the main mechanisms of failure in the SiC particle-reinforced composite.

  17. Al Parker: American Illustrator

    NSDL National Science Digital Library

    This tribute to Al Parker, the noted magazine illustrator and artist, was fashioned from extensive holdings at the Washington University Library in St. Louis. Known as "The Dean of Illustrators," Al Parker attended school at the St. Louis School of Fine Arts at Washington University and went on to become of the most prolific and important American illustrators of the twentieth century. Parker was best-known for his modernist deployment of line, patterning, and bold, flat colors, which helped shape the general "look" of the period from the 1930s to the 1960s. Using short clips of Parker's original illustrations and drawings, this exhibit offers a glimpse into his work and contributions to the medium. Of particular interest is the section devoted to Parker's famous "Mother-Daughter" covers for the Ladies Home Journal, which began in 1939 and ran for 17 years.

  18. ALS insertion devices

    SciTech Connect

    Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

    1990-11-01

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs.

  19. Nine Tips To Help Faith Leaders and Their Communities Address Teen Pregnancy = Nueve consejos para ayudar a lideres espirituales y sus comunidades a hacerle frente al problema del embarazo en la adolescencia.

    ERIC Educational Resources Information Center

    National Campaign To Prevent Teen Pregnancy, Washington, DC.

    To support faith communities in protecting teenage boys and girls from too-early sexual activity and teen pregnancy, the National Campaign To Prevent Teen Pregnancy's Task Force on Religion and Public Values has compiled these nine tips which summarize a wealth of experience and advice from faith leaders around the country. The members of the Task…

  20. Modelling the Volatility of the Spanish Wholesale Electricity Spot Market. Asymmetric GARCH Models vs. Threshold ARSV model\\/Modelización de la volatilidad en el mercado eléctrico español. Modelos GARCH frente al modelo T-ARSV

    Microsoft Academic Search

    JOSÉ M. MONTERO; MARIA C. GARCÍA-CENTENO; GEMA FERNÁNDEZ-AVILÉS

    2011-01-01

    The liberalization and deregulation of the Spanish electricity market has provoked an increase in the complexity of pricing behaviour. In particular, the volatility of electricity spot prices is the feature that best characterises the current Spanish market. Since an understanding of the volatility process in the electricity market is critically important to distributors, generators and market regulators, this article focuses

  1. EMTP IMPLEMENTATION OF A MONTE CARLO METHOD FOR LIGHTNING PERFORMANCE ANALYSIS OF TRANSMISSION LINES IMPLANTACIÓN EN EMTP DE UN PROCEDIMIENTO BASADO EN EL MÉTODO DE MONTE CARLO PARA ANALIZAR EL COMPORTAMIENTO DE LÍNEAS DE TRANSMISIÓN FRENTE AL RAYO

    Microsoft Academic Search

    Juan A. Martínez-Velasco; Ferley Castro-Aranda

    An accurate calculation of lightning overvoltages is an important issue for the analysis and design of overhead transmission lines. The different parts of a transmission line that are involved in lightning calculations must be represented taking into account the frequency ranges of transients associated to lightning. In addition, the procedures to be used in these calculations must be developed considering

  2. Partnerwahl als konsensuelle Entscheidung

    Microsoft Academic Search

    Florian Schulz; Jan Skopek; Hans-Peter Blossfeld

    2010-01-01

    Zusammenfassung  Die vorliegende Studie setzt unsere Analysen der Kontaktierungsprozesse im Online-Dating (KZfSS 2\\/2009) fort. Da Paarbeziehungen\\u000a auf einer konsensuellen Entscheidung für eine gemeinsame Beziehung beruhen, widmet sich der vorliegende Beitrag der Frage,\\u000a wie Männer und Frauen auf Erstkontaktversuche reagieren. Die Datenstruktur von Online-Dating-Börsen bietet eine einzigartige\\u000a Chance, soziologisch im Detail zu rekonstruieren, wie Paarbeziehungen als konsensuelle Wahlhandlung nach und nach entstehen.

  3. 26Al measurements with VERA

    NASA Astrophysics Data System (ADS)

    Wallner, A.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.; Vonach, H.; Wild, E.

    1998-04-01

    The Vienna Environmental Research Accelerator (VERA) is a 3-MV Pelletron tandem mass spectrometer system. Since July 1996, extensive tests with 26Al detection were performed. Systematic investigations of reproducibility, transmission, overall efficiency etc. are necessary for a new facility such as VERA in order to come up with reliable results. To this end several different 26Al standards with an 26Al/ 27Al isotopic ratio between 5 × 10 -10 and 1 × 10 -12 were used. The results of these investigations revealed no systematic deviation beyond counting statistics. In order to determine the cross section for the 27Al(n,2n) 26Al reaction Al-metal samples with 26Al produced from neutron irradiation were measured and compared with 26Al standards.

  4. Frequently Asked Questions about ALS and the ALS Registry

    MedlinePLUS

    ... Can a researcher access National ALS Registry data? How will you be sure that you have as many persons ... National ALS Registry web site. Back to Top How will you be sure that you have as many persons ...

  5. Amyotrophic Lateral Sclerosis (ALS)

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program explains amyotrophic lateral sclerosis (ALS or Lou Gehrig's Disease) including the causes, symptoms, diagnosis and treatment options. This resource is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: This tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

  6. Al Jazirah, Sudan

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

    The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  7. Al(+)-ligand binding energies

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.

    1991-01-01

    Ab initio calculations are used to optimize the structure and determine the binding energies of Al(+) to a series of ligands. For Al(+)-CN, the bonding was found to have a large covalent component. For the remaining ligands, the bonding is shown to be electrostatic in origin. The results obtained for Al(+) are compared with those previously reported for Mg(+).

  8. Studies of 27Al NMR in EuAl4

    NASA Astrophysics Data System (ADS)

    Niki, H.; Nakamura, S.; Higa, N.; Kuroshima, H.; Toji, T.; Yogi, M.; Nakamura, A.; Hedo, M.; Nakama, T.; ?nuki, Y.; Harima, H.

    2015-03-01

    EuAl4 orders antiferromagnetically at TN ? 16 K with an effective magnetic moment of 8.02 ?B. In the paramagnetic phase, the magnetic susceptibility of EuAl4 follows the Curie-Weiss law with a positive Curie-Weiss temperature ?P = +14 K. The antiferromagnetic state is changed into the field induced ferromagnetic state at a critical field Hc of approximately 2 T. In order to microscopically investigate the magnetic and electronic properties in EuAl4, the NMR measurements of EuAl4 have been carried out at temperatures between 2 and 300 K, applying an external magnetic field of approximately 6.5 T. The 27Al NMR spectra corresponding to Al(I) and Al(II) sites are obtained. From the 27Al NMR spectra, the isotropic part Kiso and anisotropic part Kaniso of Knight shift, and nuclear quadrupole frequncy ?Q are obtained. The Kiso and Kaniso shift to negative side with decreasing temperature due to the RKKY interaction. These temperature dependences follow the Curie-Weiss law with ?P = +14 K, which is consistent with that of the magnetic susceptibility. From the K – ? plot, the values of the hyperfine fields Hhf_iso and Hhf_aniso are -3.231 and -0.162 kOe/?B for Al(I) site, and -1.823 and -0.264 kOe/?B for Al(II) site, respectively. The values of ?Q of 27Al nucleus for Al(I) and Al(II) sites are approximately 0.865 and 0.409 MHz, respectively. The nuclear relaxation time T1 of 27Al NMR for both sites is almost constant in the paramagnetic phase, while the value of 1/T1 is abruptly decreased in the ordered ferromagnetic state.

  9. Al Mashriq: Lebanon

    NSDL National Science Digital Library

    Part of the Al-Mashriq online Web resource for countries located in the Levant, this site is devoted to providing a host of materials, thematically organized, about the country of Lebanon. Persons seeking to read a bit about Lebanon's early history will want to read the first chapter of Kamal Salibi's "A House of Many Mansions-The History of Lebanon," which is provided here. For those looking for a geographic orientation to the landscape of Lebanon, an interactive map provides a number of photographs and brief remarks on various important cities and cultural sites, such as Beirut and the Roman temples at Baalbak. Along with these sections, the site also offers thematic sections devoted to education, food, maps, money, politics, and religion that will be useful to those students looking for background information on Lebanon.

  10. Descenso al Infierno de VenusDescenso al Infierno de VenusDescenso al Infierno de VenusDescenso al Infierno de Venus Manuel Alfonseca

    E-print Network

    Alfonseca, Manuel

    Descenso al Infierno de VenusDescenso al Infierno de VenusDescenso al Infierno de VenusDescenso al Infierno de Venus Manuel Alfonseca #12;Manuel Alfonseca 2 #12;Descenso al infierno de Venus 3 Descenso al infierno de Venus Manuel Alfonseca RESERVADOS TODOS LOS DERECHOS. Salvo usos razonables destinados al

  11. AL Amyloidosis with Renal Involvement

    Microsoft Academic Search

    Romana Ryšavá

    2007-01-01

    Primary (AL amyloidosis) is a systemic disease characterized by an amyloid deposition process in many organs, with unsatisfactory survival of patients. The monoclonal light chains form the fibrils that deposit and accumulate in tissues. Renal involvement is very frequent in AL amyloidosis and could lead to development of nephrotic syndrome followed by the renal failure in many cases. Classic therapeutic

  12. Characteristics of CeCoIn5/Al/AlOx/Nb and CeCoIn5/Al/AlOx/Al Tunnel Junctions

    SciTech Connect

    Petrovic, C.; Nevirkovets, I.P.; Chernyashevskyy, O.; Hu, R.; Ketterson, J.B.; Sarma, B.K.

    2009-03-03

    We report characteristics of CeCoIn{sub 5}/Al/AlO{sub x}/Nb and CeCoIn{sub 5}/Al/AlO{sub x}/Al tunnel junctions fabricated on the (0 0 1) surface of CeCoIn{sub 5} crystal platelets. The main result of this work is the observation of a low Josephson current (as compared with that expected from the Ambegaokar-Baratoff formula), which is consistent with idea that the order parameter in the heavy-fermion superconductor CeCoIn{sub 5} has unconventional pairing symmetry.

  13. Allegato "B" DOMANDA DI PARTECIPAZIONE AL CONCORSO DI AMMISSIONE AL

    E-print Network

    Sandini, Giulio

    IN ROBOTICA, NEUROSCIENZE, NANOTECNOLOGIE E SCOPERTA FARMACI IN COLLABORAZIONE CON LA FONDAZIONE IIT Si prega'ammissione al Corso di Dottorato di Ricerca in Robotica, Neuroscienze, Nanotecnologie e Scoperta Farmaci

  14. (12) United States Patent Harvey et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Harvey et al. (54) ANALYZING RETURN ON INVESTMENT OF ADVERTISING US 2009/0259518 Al Oct. 15,2009 Int. Cl. G06F 17/30 (2006.01) G07G 1/00 (2006.01) U.S. Cl et al. 911980 Block et al. 511982 Eskin et al. 1111982 Barber et al. 711985 Block et al. 111996

  15. ALS ACT (Accelerated Therapeutics), The ALS Association, Northeast ALS Consortium, and the ALS Finding A Cure Foundation

    E-print Network

    MacMillan, Andrew

    pharmaceutical, biotherapeutic/biotechnology companies, academic members of the NEALS Consortium, and ALS through NEALS: Project Management Grants & Contracts Management Data Management Study Monitoring Document Review, and Ongoing Site Management Site Trainings: Good Clinical Practice, Regulatory Compliance

  16. In Memory of Al Cameron

    E-print Network

    John J. Cowan; James W. Truran

    2006-11-27

    Al Cameron, who died recently (October 3, 2005) at 80, was one of the giants in astrophysics. His insights were profound and his interests were wide-ranging. Originally trained as a nuclear physicist, he made major contributions in a number of fields, including nuclear reactions in stars, nucleosynthesis, the abundances of the elements in the Solar System, and the origin of the Solar System and the Moon. In 1957, Cameron and, independently, Burbidge, Burbidge, Fowler and Hoyle, wrote seminal papers on nuclear astrophysics. Most of our current ideas concerning element formation in stars have followed from those two pioneering and historical works. Al also made many contributions in the field of Solar System physics. Particularly noteworthy in this regard was Cameron's work on the formation of the Moon. Al was also a good friend and mentor of young people. Al Cameron will be missed by many in the community both for his scientific contributions and for his friendship.

  17. Developmental Cell Abbott et al.

    E-print Network

    Bartel, David

    seam cell nuclei. #12;#12;Developmental Cell September Abbott et al. Supplemental Experimental Procedures Detection expression is observed at the L1 stage in multiple cell types, including seam cells and neurons (n). (B, D

  18. Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2004-01-01

    In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

  19. Corrosion Behavior of Al-Al3Ni and Al-Al2Cu Functionally Graded Materials Fabricated by a Centrifugal Method

    NASA Astrophysics Data System (ADS)

    Noda, Kazuhiko; Miyahara, Keita; Watanabe, Yoshimi

    2008-02-01

    Intermetallic compounds, such as Al3Ni and Al2Cu, are effective for enhancing the mechanical properties of an alloy. Al-Al3Ni and Al-Al2Cu functionally graded materials (FGMs) might be attractive materials for advanced materials. Al-Al3Ni and Al-Al2Cu FGMs were fabricated by a centrifugal method; the centrifugal method is an extremely effective method for fabricating FGMs. Al-Al3Ni and Al-Al2Cu FGMs that had a graded distribution of intermetallic compounds could be produced by this in-situ centrifugal method. Particle size, particle shape and the distribution of intermetallic compounds were controlled by varying the content of the alloy element (Ni, Cu) in the master alloy, the cooling rate in casting and the gravity number. The casting mechanism is explained in terms of the microstructures of the Al-Al3Ni and Al-Al2Cu FGMs fabricated by this method. The corrosion behavior of the FGMs was investigated by electrochemical analysis. Polarization curves of the FGMs in a borate solution were measured by a potentiodynamic method. The presence of Al2Cu exerted a larger effect on the corrosion behavior of the FGMs than Al3Ni. Analysis of the polarization curve parameters was effective for evaluating the corrosion resistance of the FGMs.

  20. 77 FR 73732 - In the Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ...Front, Jabhat al- Nusrah, Jabhet al-Nusra, The Victory Front, Al Nusrah Front...aka Jabhat al-Nusrah, aka Jabhet al-Nusra, aka The Victory Front, aka Al...Front, Jabhat al-Nusrah, Jabhet al-Nusra, The Victory Front, Al Nusrah...

  1. ALS Association's Patient Bill of Rights for People Living with ALS

    MedlinePLUS

    ... Caregivers Newly Diagnosed ALS Registry Military Veterans Augmentative Communication Caregivers Resources ALS Insight Newsletter Living with ALS Manuals ALS Association Brochures Webinars Our Videos Factsheets Library Order Form Products to Aid in ...

  2. Uranium cobalt tetraaluminide, UCoAl4.

    PubMed

    Stêpien-Damm, J; Tougait, O; Zaremba, V I; Noël, H; Troc, R

    2004-01-01

    The structure of UCoAl(4) can be viewed as a succession of atomic layers, with the compositions UCoAl and Al(3), that alternate along the c axis. The packing within the pure Al layer at z = 1/2 results from edge-sharing of triangles, squares and pentagons of Al atoms. Two successive Al(3) layers thus define pentagonal, square-based and trigonal prisms which are centred at z = 0 by the U, Co and remaining Al atoms. UCoAl(4) is a high-temperature phase that is only observed in as-cast samples. PMID:14712016

  3. AlN/Fe/AlN nanostructures for magnetooptic magnetometry

    SciTech Connect

    Lišková-Jakubisová, E., E-mail: liskova@karlov.mff.cuni.cz; Viš?ovský, Š. [Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 12116 Prague 2 (Czech Republic); Široký, P.; Hrabovský, D.; Pištora, J. [Nanotechnology Center, Technical University of Ostrava, 17. listopadu 15/2172, 70833 Ostrava Poruba (Czech Republic); Harward, I.; Celinski, Z. [Center for Magnetism and Magnetic Nanostructures, University of Colorado at Colorado Springs, 1420 Austin Bluffs Pkwy., Colorado Springs, Colorado 80918 (United States)

    2014-05-07

    AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of ??=?410?nm (3.02?eV) and operate at oblique light incidence angles, ?{sup (0)}, to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at ?{sup (0)}???5° and longitudinal Kerr effect spectra (?{sup (0)}?=?45°) at photon energies between 1 and 5?eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

  4. Dopant-Free GaN/AlN/AlGaN Radial Nanowire Heterostructures as High

    E-print Network

    Li, Yat

    Dopant-Free GaN/AlN/AlGaN Radial Nanowire Heterostructures as High Electron Mobility Transistors, 2006 ABSTRACT We report the rational synthesis of dopant-free GaN/AlN/AlGaN radial nanowire-organic chemical vapor deposition (MOCVD). Transmission electron microscopy (TEM) studies reveal that the GaN/ AlN/AlGaN

  5. Modulation-doped (Al,Ga)As/AlAs superlattice: Electron transfer into AlAs

    SciTech Connect

    Drummond, T.J.; Fritz, I.J.

    1985-08-01

    A modulation-doped superlattice of n-(Al,Ga)As and undoped AlAs has been grown by molecular beam epitaxy. At cryogenic temperatures, electrons transfer into the undoped AlAs layers and enhanced mobilities as high as 1000 cm/sup 2//Vs are observed for the first time. It is shown that by properly accounting for the depth of the donor level in modulation-doped heterostructures reasonably good limits can be set on the gamma point conduction-band discontinuity at the heterojunction. It is found that this discontinuity is approximately 60--65% of the band-gap difference between the two alloys, in good agreement with other recent determinations.

  6. Microstructure Evolution and Mechanical Properties of Al/Al-Mg/Al composite sheet metals

    NASA Astrophysics Data System (ADS)

    Cho, Jaehyung; Kim, Su-Hyeon; Kim, Hyoung-Wook; Lim, Cha-Yong; Kim, Eun-Young; Choi, Shi-Hoon

    2011-08-01

    Two different types of aluminum alloys of AA1050 and AA5182 were used to manufacture Al/Al-Mg/Al composite sheet metals by roll bonding technology at room temperature. The composite sheet metals were annealed at 400 °C and carried out uniaxial tension tests to investigate mechanical properties. Macroscopic mechanical properties are strongly dependent on the volume (or thickness) fraction of two component layers. Microstructure and texture evolution were also investigated during roll bonding process. The AA1050 sheets located in the outer layer mainly consist of shear texture components and the AA5182 sheet located in the center layer consists of plane strain texture components. With differential speeds of the top and bottom rolls, roll bonding was also carried out. Elongation along the RD and TD was improved at a speed difference of approximately 10%-20%.

  7. Lynch et al. Proceedings 109

    E-print Network

    Moorcroft, Paul R.

    Lynch et al. Proceedings 109 Insect­Fire Interactions in Yellowstone National Park: The Influence@fas.harvard.edu) Roy A. Renkin Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190 (307 of mountain pine beetle (Dendroctonus ponderosae Hopkins) activity within Yellowstone National Park, Wyoming

  8. AnnuAl report JAhresbericht

    E-print Network

    van der Torre, Leon

    AnnuAl report JAhresbericht rApport d'Activités 2010 #12;#12;1LE MOT DU RECTEUR LE MOT DU RECTEUR of laboratory space. This will change in the year 2011 with the inauguration of the LCSB building in Belval GOUVERNANCE RAPPORT ANNUEL 2010 LE CONSEIL DE GOUVERNANCE P. 05 L'�QUIPE RECTORALE P. 11 LES ORGANES

  9. Transformer Abdullah Al-Otaibi

    E-print Network

    Masoudi, Husain M.

    Transformer Abdullah Al-Otaibi ID#242374 Section#2 Abstract- this is a brief description for transformer and how it works. I. DEFINITION A transformer is a device that transfers electrical energy from of the transformer in 1831. The transformer is used by Faraday only to demonstrate the principle of electromagnetic

  10. Dynamic Modeling of ALS Systems

    NASA Technical Reports Server (NTRS)

    Jones, Harry

    2002-01-01

    The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

  11. Sobrevivir al cáncer: comer bien

    Cancer.gov

    Sobrevivir al cáncer: comer bien Por el Instituto Nacional del Cáncer Bethesda, MD. - Más de 13 millones de personas que viven en Estados Unidos han recibido un diagnóstico de cáncer. Muchas de las personas que han tenido cáncer quieren seguir una

  12. (12) United States Patent Reardan et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Reardan et al. (54) SENSITIVE DRUG DISTRIBUTION SYSTEM AND METHOD (75 2004/0117205 Al Jun. 17,2004 (51) Int. Cl. G06Q 10/00 (2006.01) (52) U.S. Cl/231 4,976,351 A 1211990 Mangini et al. 5,737,539 A * 411998 Edelson et al. ................. 705/3 5

  13. (12) United States Patent Likourezos et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Likourezos et al. (54) SYSTEM AND METHOD FOR AUTOMATICALLY EFFECTING Publication Data US 2002/0095376 Al Jul. 18, 2002 Related U.S. Application Data Continuation Altman et al. ................ 705/36 5,715,314 A 211998 Payne et al. 5,794,219 A 811998 Brown 5

  14. Identification of Candida albicans ALS2 and ALS4 and Localization of Als Proteins to the Fungal Cell Surface

    PubMed Central

    Hoyer, L. L.; Payne, T. L.; Hecht, J. E.

    1998-01-01

    Additional genes in the growing ALS family of Candida albicans were isolated by PCR screening of a genomic fosmid library with primers designed from the consensus tandem-repeat sequence of ALS1. This procedure yielded fosmids encoding ALS2 and ALS4. ALS2 and ALS4 conformed to the three-domain structure of ALS genes, which consists of a central domain of tandemly repeated copies of a 108-bp motif, an upstream domain of highly conserved sequences, and a domain of divergent sequences 3? of the tandem repeats. Alignment of five predicted Als protein sequences indicated conservation of N- and C-terminal hydrophobic regions which have the hallmarks of secretory signal sequences and glycosylphosphatidylinositol addition sites, respectively. Heterologous expression of an N-terminal fragment of Als1p in Saccharomyces cerevisiae demonstrated function of the putative signal sequence with cleavage following Ala17. This signal sequence cleavage site was conserved in the four other Als proteins analyzed, suggesting identical processing of each protein. Primary-structure features of the five Als proteins suggested a cell-surface localization, which was confirmed by indirect immunofluorescence with an anti-Als antiserum. Staining was observed on mother yeasts and germ tubes, although the intensity of staining on the mother yeast decreased with elongation of the germ tube. Similar to other ALS genes, ALS2 and ALS4 were differentially regulated. ALS4 expression was correlated with the growth phase of the culture; ALS2 expression was not observed under many different in vitro growth conditions. The data presented here demonstrate that ALS genes encode cell-surface proteins and support the conclusion that the size and number of Als proteins on the C. albicans cell surface vary with strain and growth conditions. PMID:9765564

  15. AnnuAl report JAhresbericht

    E-print Network

    van der Torre, Leon

    AnnuAl report JAhresbericht rApport d'Activités 2011 #12;1LE MOT DU RECTEUR Le mot du RecteuR Le'Université puisqu'il y existe une diversité de perspectives par rapport aux personnes ou aux structures devant for Systems Biomedicine moved into its new building in Belval. Belval is slowly becoming the fourth campus

  16. Nucleants of Eutectic Silicon in Al-Si Hypoeutectic Alloys: ?-(Al, Fe, Si) or AlP Phase

    NASA Astrophysics Data System (ADS)

    Liang, Song-Mao; Schmid-Fetzer, Rainer

    2014-11-01

    A thermodynamic description of the Al-Si-P-Fe quaternary system focused on Al-(Si)-rich alloys is developed. The solidification sequence in typical Al-7Si cast alloys is derived using thermodynamic calculations of the phase diagrams and solidification simulation under Scheil and constrained Scheil conditions. The previously claimed nucleation of eutectic silicon by ?-(Al,Fe,Si) particles is not possible because under all conditions, ?-(Al,Fe,Si) precipitates after (Si) in pertinent alloys. Variation of P in the ppm range is crucial because it changes the solidification sequence of AlP and (Si).

  17. The Collections - Dar al-Athar al-Islamiyyah

    NSDL National Science Digital Library

    Regarded by experts as one of a handful of the most comprehensive collections of Islamic art in the world, the al-Sabah holdings in Kuwait feature 20,000 objects from geographically and chronologically diverse locations. Nine categories - Metals, Ceramics, Glass, Ivory & Wood, Jewelry & Hardstone, Numismatics, Rugs & Textiles, Manuscripts & Calligraphy, and Stone & Stucco - can be accessed from the collections page with the click of a mouse. Within each category, short essays contextualize the beautiful photographs of ancient, medieval, and modern Islamic art in a wide variety of mediums and styles.

  18. Thermal expansion of gehlenite, Ca 2 Al[AlSiO 7 ], and the related aluminates Ln CaAl[Al 2 O 7 ] with Ln =Tb, Sm

    Microsoft Academic Search

    L. Peters; K. Knorr; M. Knapp; W. Depmeier

    2005-01-01

    The thermal expansion of gehlenite, Ca2Al[AlSiO7], (up to T=830 K), TbCaAl[Al2O7] (up to T=1,100 K) and SmCaAl[Al2O7] (up to T=1,024 K) has been determined. All compounds are of the melilite structure type with space group\\u000a $$P\\\\bar {4}2_1\\\\,m.$$ Thermal expansion data was obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches Elektronen Synchrotron (DESY) in Hamburg (Germany). The

  19. Thermal expansion of gehlenite, Ca2Al[AlSiO7], and the related aluminates LnCaAl[Al2O7] with Ln = Tb, Sm

    Microsoft Academic Search

    L. Peters; K. Knorr; M. Knapp; W. Depmeier

    2005-01-01

    The thermal expansion of gehlenite, Ca2Al[AlSiO7], (up to T=830 K), TbCaAl[Al2O7] (up to T=1100 K) and SmCaAl[Al2O7] (up to T=1024 K) has been determined. All compounds are of the melilite structure type with space group P{bar{4}}21m. Thermal expansion data were obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches Elektronen Synchrotron (DESY) in Hamburg

  20. Thermal expansion of gehlenite, Ca 2 Al[AlSiO 7 ], and the related aluminates Ln CaAl[Al 2 O 7 ] with Ln = Tb, Sm

    Microsoft Academic Search

    L. Peters; K. Knorr; M. Knapp; W. Depmeier

    2005-01-01

    The thermal expansion of gehlenite, Ca2Al[AlSiO7], (up to T=830 K), TbCaAl[Al2O7] (up to T=1100 K) and SmCaAl[Al2O7] (up to T=1024 K) has been determined. All compounds are of the melilite structure type with space group\\u000a $$P{\\\\bar{4}}2_{1}m.$$ Thermal expansion data were obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches\\u000a Elektronen Synchrotron (DESY) in Hamburg (Germany). The thermal

  1. NiAl-base composite containing high volume fraction of AlN for advanced engines

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan (inventor); Whittenbeger, John D. (inventor); Lowell, Carl F. (inventor)

    1994-01-01

    A particulate reinforced NiAl-AlN composite alloy has a NiAl matrix and greater than about 13 volume percent fine particles of AlN within the matrix. The particles preferably have a diameter from about 15 nanometers to about 50 nanometers. The particulate reinforced NiAl-AlN composite alloy may be prepared by cryomilling prealloyed NiAl in liquid nitrogen using grinding media having a diameter of from about 2 to 6 mm at an impeller speed of from about 450 RPM to about 800 RPM. The cryomilling may be done for a duration of from about 4 hours to about 20 hours to obtain a cryomilled powder. The cryomilled powder may be consolidated to form the particulate reinforced NiAl-AlN composite alloy. The particulate reinforced alloy can further include a toughening alloy. The toughening alloy may include NiCrAlY, FeCrAlY, and FeAl.

  2. Contribution of interface capacitance to the electric-field breakdown in thin-film AlAlOx Al capacitors

    E-print Network

    Hebard, Arthur F.

    ) of the true breakdown electric field Eb across the dielectric. By modeling this interface contribution the dielectric, this cor- responds to a surface charge density on the aluminum elec- trodes at breakdown givenContribution of interface capacitance to the electric-field breakdown in thin-film Al­AlOx ­Al

  3. Isolde Lasoen ALS ontsnapt aan uitsluiting

    E-print Network

    gezet kooitje kan gepord worden tot vermaak van het volk. Een Guantanamo Bay voor huisdieren, zeg maar, al hoef je voor een verblijf in Guantanamo geen 6 of 8 euro te beta- len, gewoon hoesten als een

  4. (12) United States Patent Vertes et al.

    E-print Network

    Vertes, Akos

    (12) United States Patent Vertes et al. (54) LASER DESORPTION IONIZATION AND PEPTIDE SEQUENCING. (21) Appl. No.: 11/674,671 (22) Filed: Feb. 14,2007 (65) Prior Publication Data US 2009/0321626 Al Dec Suizdak et al. 6,589,485 B2 7/2003 Koster 6,794,196 B2 912004 Fonash et al. 6,846,681 B2 112005 Buriak et

  5. (12) United States Patent Vertes et al.

    E-print Network

    Vertes, Akos

    (12) United States Patent Vertes et al. (54) THREE-DIMENSIONAL MOLECULAR IMAGING BY INFRARED LASER/0012831 Al Jan. 21, 2010 Related U.S. Application Data (63) Continuation-in-part of application No. 121176,656,690 B2 6,744,046 B2 6,991,903 B2 7,084,396 B2 12/2003 Crooke et al. 612004 Valaskovic et al. 112006 Fu

  6. (12) United States Patent Fallon et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Fallon et al. (54) SYSTEM AND METHOD FOR DATA FEED ACCELERATION/131,631 (22) Filed: Jun. 2,2008 (65) Prior Publication Data US 200910287839 Al Nov. 19,2009 Related U References Cited U.S. PATENT DOCUMENTS 3,394,352 A 7/1968 Wernikoff et al. 3,490,690 A 111970 Apple et al. 4

  7. (12) United States Patent Reardan et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Reardan et al. (54) SENSITIVE DRUG DISTRIBUTION SYSTEM AND METHOD (75 US 2005/0090425 Al Apr. 28, 2005 Related U.S. Application Data Division of application No.1 0,847,764 A 711989 Halvorson 4,976,351 A 1211990 Mangini et al. 5,737,539 A 411998 Edelson et al. 5,845,255 A 1211998

  8. Aluminium distribution in ZSM-5 revisited: The role of Al-Al interactions

    SciTech Connect

    Ruiz-Salvador, A. Rabdel, E-mail: rabdel@imre.oc.uh.cu [Group of Materials Developed by Design, Division of Chemistry and Technology of Materials, Institute of Materials Science and Engineering (IMRE), University of Havana, Havana 10400 (Cuba); Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W. [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom)] [Department of Chemistry, University College London, 20 Gordon Street, London, WC1H OAJ (United Kingdom)

    2013-02-15

    We present a theoretical study of the distribution of Al atoms in zeolite ZSM-5 with Si/Al=47, where we focus on the role of Al-Al interactions rather than on the energetics of Al/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of Al siting in a Si{sub 94}Al{sub 2}O{sub 192} cell. The equilibrium Al distribution is determined by the interplay of two factors: the energetics of the Al/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the Al-Al interaction, which at this Si/Al maximises Al-Al distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two Al atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on Al-Al distances. - Graphical abstract: Role of Al-Al interactions in high silica ZSM-5 is shown to be anisotropic in nature and not dependent solely on Coulombic interactions. Highlights: Black-Right-Pointing-Pointer Si-Al distribution in ZSM-5 is revisited, stressing the role of the Al-Al interaction. Black-Right-Pointing-Pointer Coulomb interactions are not the key factors controlling the Al siting. Black-Right-Pointing-Pointer Anisotropy of the framework is identified as a source of departure from Dempsey's rule.

  9. Effect of Al-Si-Al and Al-Si-Si-Al Pairs in the ZSM-5 Zeolite Framework on the 27 NMR Spectra. A Combined High-Resolution 27

    E-print Network

    Sklenak, Stepan

    Effect of Al-Si-Al and Al-Si-Si-Al Pairs in the ZSM-5 Zeolite Framework on the 27 Al NMR Spectra. A Combined High-Resolution 27 Al NMR and DFT/MM Study Jiri´ Dedecek, Stepan Sklenak,*, Chengbin Li, Blanka of the presence of Al-O-Si-O-Al and Al-O-Si-O-Si-O-Al sequences in the ZSM-5 zeolite framework on the local

  10. United States Patent [19] Church et al.

    E-print Network

    Church, George M.

    United States Patent [19] Church et al. [54] CHARACTERIZATION OF INDIVIDUAL POLYMER MOLECULES BASED al.. "ANeutral Amino Acid Change in Segment TIS4 Dramatically Alters the Gating Properties of the Volt- age-Dependent Sodium Channel". 1990, Proc. Natl. Acad. Sci. USA, 87:323-27. Bensirnon. A.. et al

  11. (12) United States Patent Likourezos et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Likourezos et al. (54) SYSTEM AND METHOD FOR EFFECTING A REAL: Nov. 14, 2001 (65) Prior Publication Data US 2002/0095377 Al Jul. 18, 2002 Related U.S. Application Cited U.S. PATENT DOCUMENTS 4,799,156 A 4,876,648 A 111989 Shavit et al. 1011989 Lloyd 102 102 111111

  12. Klimes et al. 1997 Dioscorea japonica

    E-print Network

    Tomimatsu,, Hiroshi

    and Silvertown 2004 Charpentier et al. 2000 Eckert 2000 Maynard Smith 1980 Utricularia australis f. tenuicaulis U. macrorhiza U. australis F1 Kameyama et al. 2005 Kameyama and Ohara 2006 3 genet #12;262 Barrett et al. 1993, Ohara M (2005) Hybrid origins and F1 dominance in the free-floating, sterile bladderwort, Utricularia

  13. Wear behavior of Al-Al{sub 3}Ti composite manufactured by a centrifugal method

    SciTech Connect

    Watanabe, Yoshimi; Yamanaka, Noboru; Fukui, Yasuyoshi

    1999-12-01

    The purpose of the present study was to develop a wear-resistant, light Al-Al{sub 3}Ti composite material. An Al-Al{sub 3}Ti composite specimen was machined from a thick-walled tube of Al-Al{sub 3}Ti functionally graded material (FGM) manufactured by the centrifugal method from a commercial ingot of Al-5 mass% Ti master alloy. The alloy was heated to a temperature where solid Al{sub 3}Ti particles resided in a liquid Al matrix, and then the centrifugal method was carried out. Al{sub 3}Ti particles in a commercial alloy ingot exist as platelets, and this shape was maintained through the casting. Three kinds of wear specimens were prepared, taking into account the morphology of the Al{sub 3}Ti particles in the thick-walled FGM tube; the Al{sub 3}Ti particles were arranged with their platelet planes nearly normal to the radial direction as a result of the applied centrifugal force. The wear resistance of the Al-Al{sub 3}Ti composite was significantly higher than that of pure Al. Wear-resistance anisotropy and dissolution of the Al{sub 3}Ti into the Al matrix at the near-surface region, around 100 {micro}m in depth, were also observed. The mechanism of the supersaturated-layer formation and the origin of the anisotropic wear resistance are discussed.

  14. Systems Engineering Techniques for ALS Decision Making

    NASA Technical Reports Server (NTRS)

    Rodriquez, Luis F.; Drysdale, Alan E.; Jones, Harry; Levri, Julie A.

    2004-01-01

    The Advanced Life Support (ALS) Metric is the predominant tool for predicting the cost of ALS systems. Metric goals for the ALS Program are daunting, requiring a threefold increase in the ALS Metric by 2010. Confounding the problem, the rate new ALS technologies reach the maturity required for consideration in the ALS Metric and the rate at which new configurations are developed is slow, limiting the search space and potentially giving the perspective of a ALS technology, the ALS Metric may remain elusive. This paper is a sequel to a paper published in the proceedings of the 2003 ICES conference entitled, "Managing to the metric: an approach to optimizing life support costs." The conclusions of that paper state that the largest contributors to the ALS Metric should be targeted by ALS researchers and management for maximum metric reductions. Certainly, these areas potentially offer large potential benefits to future ALS missions; however, the ALS Metric is not the only decision-making tool available to the community. To facilitate decision-making within the ALS community a combination of metrics should be utilized, such as the Equivalent System Mass (ESM)-based ALS metric, but also those available through techniques such as life cycle costing and faithful consideration of the sensitivity of the assumed models and data. Often a lack of data is cited as the reason why these techniques are not considered for utilization. An existing database development effort within the ALS community, known as OPIS, may provide the opportunity to collect the necessary information to enable the proposed systems analyses. A review of these additional analysis techniques is provided, focusing on the data necessary to enable these. The discussion is concluded by proposing how the data may be utilized by analysts in the future.

  15. Opportunity's 'Rub al Khali' Panorama

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub al Khali' Panorama (QTVR)

    This panoramic image, dubbed 'Rub al Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.'

    The rover was stuck in the dune's deep fine sand for more than a month. 'Rub al Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth.

    The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers.

    Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars.

    Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can be seen in this color image to be dustier than the undisturbed or 'normal' plains soils in Meridiani. Since the time these ruts were made, some of the dust there has been blown away by the wind, reaffirming the dynamic nature of the martian environment, even in this barren, ocean-like desert of sand.

  16. Colombia frente a la coyuntura financiera internacional

    Microsoft Academic Search

    Fernando E. Suescún

    2002-01-01

    Las perspectivas de la economía colombiana y en particular su situación fiscal y cambiaria se analizan a la luz de las políticas sugeridas por el Consenso de Washington (ajuste fiscal, privatización y apertura) y las críticas a este enfoque realizadas por el premio Nobel, Joseph Stiglitz. A partir de la experiencia de los países del sudeste asiático y su respuesta

  17. A nuclear magnetic resonance probe of Fe-Al and Al20V2Eu intermetallics

    E-print Network

    Chi, Ji

    2009-05-15

    . To study the variety of magnetic properties, we use NMR, magnetic susceptibility, specific heat and other methods in this work. The microscopic electronic and magnetic properties of the Al-rich Fe-Al system and Al20V2Eu have been studied via 27Al NMR...

  18. Reactive Plasma Spraying of Fine Al2O3/AlN Feedstock Powder

    NASA Astrophysics Data System (ADS)

    Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

    2013-12-01

    Reactive plasma spraying (RPS) is a promising technology for in situ formation of aluminum nitride (AlN) coatings. Recently, AlN-based coatings were fabricated by RPS of alumina (Al2O3) powder in N2/H2 thermal plasma. This study investigated the feasibility of RPS of a fine Al2O3/AlN mixture and the influence of the plasma gases (N2, H2) on the nitriding conversion, and coating microstructure and properties. Thick AlN/Al2O3 coatings with high nitride content were successfully fabricated. The coatings consist of h-AlN, c-AlN, Al5O6N, ?-Al2O3, and a small amount of ?-Al2O3. Use of fine particles enhanced the nitriding conversion and the melting tendency by increasing the surface area. Furthermore, the AlN additive improved the AlN content in the coatings. Increasing the N2 gas flow rate improved the nitride content and complete crystal growth to the h-AlN phase, and enhanced the coating thickness. On the other hand, though the H2 gas is required for plasma nitriding of the Al2O3 particles, increasing its flow rate decreased the nitride content and the coating thickness. Remarkable influence of the plasma gases on the coating composition, microstructure, and properties was observed during RPS of the fine particles.

  19. Comparative Genomic Discovery of miRNAs Grad et al.

    E-print Network

    Church, George M.

    Comparative Genomic Discovery of miRNAs Grad et al. Computational and Experimental Identification throughout the adult life cycle (Feinbaum and Ambros, 1999; Lee et al., 1993; Reinhart et al., 2000 al., 1993; Wightman et al., 1993; Reinhart et al., 2000; Slack et al., 2000). Both lin-4 and let-7

  20. Single crystal growth and characterization of binary stoichiometric and Al-rich Ni 3Al

    Microsoft Academic Search

    D. Golberg; M Demura; T Hirano

    1998-01-01

    Binary stoichiometric Ni3Al (Ni–25at% Al) single crystals and Al-rich single-crystal-like (Ni–26at% Al, Ni–27at% Al) alloys that do not contain any ternary additions have been successfully grown for the first time, by using the floating zone method. The quality of the crystals was examined by the Laue X-ray back-reflection method and optical microscopy. The stoichiometric single crystals had good crystallinity. The

  1. Oxidation resistance of intermetallic compounds Al 3 Ti and TiAl

    Microsoft Academic Search

    Y. Umakoshi; M. Yamaguchi; T. Sakagami; T. Yamane

    1989-01-01

    The oxidation kinetics and morphological features of Al3Ti and TiAl were investigated. The oxidation resistance of Al3Ti is much better than that of TiAl, for example, by a factor of about 30 at 1000° C for 48 h. The big difference in the oxidation resistance is related to the characteristics of the external oxide scales of a protective Al2O3 or

  2. Cohesive, electronic and magnetic properties of the transition metal aluminides FeAl CoAl and NiAl

    Microsoft Academic Search

    V. Sundararajan; B. R. Sahu; D. G. Kanhere; P. V. Panat; G. P. Das

    1995-01-01

    Electronic structure calculations using the tight-binding linear muffin tin orbital (TB-LMTO) method have been performed for three transition metal aluminides, viz. FeAl, CoAl and NiAl. The band structures and density of states (DOS), valence electron charge density contours and Fermi surfaces have been obtained and compared with the available experimental results as well as with existing theoretical calculations. The lattice

  3. First-principles studies of typical long-period superstructures Al 5Ti 3, hAl 2Ti and r-Al 2Ti in Al-rich TiAl alloys

    Microsoft Academic Search

    Ping-Ying Tang; Bi-Yu Tang; Xu-Ping Su

    2011-01-01

    First-principles calculations are performed to study the structural stabilities, electronic and elastic properties of typical long-period superstructures Al5Ti3, h-Al2Ti and r-Al2Ti in Al-rich TiAl alloys together with ?-TiAl. The obtained lattice parameters by relaxation of crystalline cells are in good agreement with the experimental data. The calculated formation enthalpies show that r-Al2Ti has the highest structure stability from energetic point

  4. Reply to Vance et al.

    SciTech Connect

    Woon-Chee Yee; Elliott, J.L; Kwon, J.M.; Goodfellow, P. [Washington Univ. School of Medicine, St. Louis, MO (United States)

    1996-07-01

    In our report of a family with a motor and sensory polyneuropathy that was linked to chromosome 3q, we classified this neuropathy as a form of hereditary motor and sensory neuropathy II (HMSN II, also known as {open_quotes}CMT2{close_quotes}). Doubts have been raised by Vance et al. as to whether this neuropathy should be classified as hereditary sensory autonomic neuropathy I (HSAN I) instead of HMSN II. While it is reasonable to raise such doubts, we believe that the neuropathy is best designated as HMSN II for the reasons described below. The group of disorders described as HSAN are characterized by primary or predominant involvement of sensory and autonomic neurons that fail to develop or that undergo atrophy and degeneration. These disorders were extensively reviewed by Dyck and Ohta, who initially described them as the hereditary sensory neuropathies (HSN). It was Dyck who subsequently suggested that these disorders be designated HSAN rather than HSN, because of the presence of autonomic involvement. 8 refs.

  5. Crack-Free AlN/GaN Distributed Bragg Reflectors on AlN Templates

    NASA Astrophysics Data System (ADS)

    Yagi, Kouta; Kaga, Mitsuru; Yamashita, Kouji; Takeda, Kenichirou; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Amano, Hiroshi; Akasaki, Isamu

    2012-05-01

    We have demonstrated crack-free 30-pair-AlN/GaN distributed Bragg reflectors (DBRs) grown on AlN templates for the first time. A reasonably high reflectivity of 97.5% was obtained. X-ray diffraction measurements revealed that the AlN templates cause compressive stress in DBRs. At the same time, the AlN/GaN DBRs were found to relax to average AlGaN alloys with AlN mole fractions determined by the thickness ratio of the AlN layer to one pair of AlN and GaN in DBRs regardless of the underlying template, AlN or GaN.

  6. Charging effect of Al{sub 2}O{sub 3} thin films containing Al nanocrystals

    SciTech Connect

    Liu, Y. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Chen, T. P.; Zhu, W.; Yang, M.; Cen, Z. H.; Wong, J. I. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Li, Y. B. [Center for Composite Materials, School of Astronautics, Harbin Institute of Technology, P.O. Box 3010, Harbin 150080 (China); Zhang, S. [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Chen, X. B. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Fung, S. [Department of Physics, University of Hong Kong (Hong Kong)

    2008-10-06

    In this work, Al{sub 2}O{sub 3} thin film containing Al nanocrystals (nc-Al) is deposited on Si substrate by radio frequency sputtering to form a metal-insulator-semiconductor structure. Both electron and hole trapping in nc-Al are observed. The charge storage ability of the nc-Al/Al{sub 2}O{sub 3} thin films provides the possibility of memory applications. Charging in the nc-Al also leads to a change in the dc resistance of the thin films, namely, the electron trapping in the nc-Al leads to an increase in the resistance, whereas the resistance is reduced if there is hole trapping in the nc-Al.

  7. Tensile Behavior of Al2o3/feal + B and Al2o3/fecraly Composites

    NASA Technical Reports Server (NTRS)

    Draper, S. L.; Eldridge, J. I.; Aiken, B. J. M.

    1995-01-01

    The feasibility of Al2O3/FeAl + B and Al2O3/FeCrAlY composites for high-temperature applications was assessed. The major emphasis was on tensile behavior of both the monolithics and composites from 298 to 1100 K. However, the study also included determining the chemical compatibility of the composites, measuring the interfacial shear strengths, and investigating the effect of processing on the strength of the single-crystal Al2O3 fibers. The interfacial shear strengths were low for Al203/FeAl + B and moderate to high for Al203/FeCrAlY. The difference in interfacial bond strengths between the two systems affected the tensile behavior of the composites. The strength of the Al203 fiber was significantly degraded after composite processing for both composite systems and resulted in poor composite tensile properties. The ultimate tensile strength (UTS) values of the composites could generally be predicted with either rule of mixtures (ROM) calculations or existing models when using the strength of the etched-out fiber. The Al2O3/FeAl + B composite system was determined to be unfeasible due to poor interfacial shear strengths and a large mismatch in coefficient of thermal expansion (CTE). Development of the Al2O3/FeCrAlY system would require an effective diffusion barrier to minimize the fiber strength degradation during processing and elevated temperature service.

  8. Teatro al Sur y la escena Argentina

    E-print Network

    2000-04-01

    140 LATIN AMERICAN THEATRE REVIEW Teatro al Sur y la escena Argentina Acaba de aparecer un nuevo número de Teatro al Sur, Revista Latinoamericana. Su título de tapa - Teatro Argentino a varias voces - resume la intención de esta nueva entrega... publicación: nos pareció oportuno apelar al testimonio directo de algunos de nuestros creadores y a través de sus voces - con particulares texturas y coloraturas - ir configurando un fragmento significativo del presente de nuestra escena. Hemos preferido...

  9. Mangan-Nickel-und Cobaltverbindungen als Konversionselektrodenmaterialien

    E-print Network

    Hoffmann, Rolf

    Mangan- Nickel- und Cobaltverbindungen als Konversionselektrodenmaterialien für Lithium ____________________________________________________63 5.1 SYNTHESE UND CHARAKTERISIERUNG VON NANOSKALIGEM LIF ______________________________63 5

  10. Superbend era begins swiftly at the ALS

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2001-11-29

    The successful installation and commissioning of high-field superconducting bend magnets (superbends) in three curved sectors of ALS storage ring was the first time the magnet lattice of an operating synchrotron light source has been retrofitted in this fundamental way. As a result, the ALS now offers an expanded spectral range well into the hard x-ray region without compromising either the number of undulators or their high brightness in the soft x-ray region for which the ALS design was originally optimized. In sum, when the superbend-enhanced ALS started up for user operations in October 2001, it marked the beginning of a new era in its history.

  11. Microstructures and wear resistances of hybrid Al–(Al 3Ti+Al 3Ni) FGMs fabricated by a centrifugal method

    Microsoft Academic Search

    Yoshimi Watanabe; Tatsuru Nakamura

    2001-01-01

    The Al based functionally graded materials (FGMs), reinforced by a hybrid of Al3Ti platelets and Al3Ni granular particles, were fabricated by the centrifugal method with both ingots of commercial Al–5mass%Ti and Al–20mass%Ni master alloys. The ratios of Al–Ti and Al–Ni alloys were 3:1, 1:1 and 1:3 (in mass), and the applied G numbers are 30, 50 and 80. The microstructures

  12. Toxicity of Al to Desulfovibrio desulfuricans

    PubMed Central

    Amonette, J. E.; Russell, C. K.; Carosino, K. A.; Robinson, N. L.; Ho, J. T.

    2003-01-01

    The toxicity of Al to Desulfovibrio desulfuricans G20 was assessed over a period of 8 weeks in a modified lactate C medium buffered at four initial pHs (5.0, 6.5, 7.2, and 8.3) and treated with five levels of added Al (0, 0.01, 0.1, 1.0, and 10 mM). At pH 5, cell population densities decreased significantly and any effect of Al was negligible compared to that of the pH. At pHs 6.5 and 7.2, the cell population densities increased by 30-fold during the first few days and then remained stable for soluble-Al concentrations of <5 × 10?5 M. In treatments having total-Al concentrations of ?1 mM, soluble-Al concentrations exceeded 5 × 10?5 M and limited cell population growth substantially and proportionally. At pH 8.3, soluble-Al concentrations were below the 5 × 10?5 M toxicity threshold and cell population density increases of 20- to 40-fold were observed. An apparent cell population response to added Al at pH 8.3 was attributed to the presence of large, spirilloidal bacteria (accounting for as much as 80% of the cells at the 10 mM added Al level). Calculations of soluble-Al speciation for the pH 6.5 and 7.2 treatments that showed Al toxicity suggested the possible presence of the Al13O4(OH)24(H2O)127+ “tridecamer” cation and an inverse correlation of the tridecamer concentration and the cell population density. Analysis by 27Al nuclear magnetic resonance spectroscopy, however, yielded no evidence of this species in freshly prepared samples or those taken 800 days after inoculation. Exclusion of the tridecamer species from the aqueous speciation calculations at pHs 6.5 and 7.2 yielded inverse correlations of the neutral Al(OH)3 and anionic Al(OH)4? monomeric species with cell population density, suggesting that one or both of these ions bear primary responsibility for the toxicity observed. PMID:12839782

  13. Thermal expansion of gehlenite, Ca2Al[AlSiO7], and the related aluminates LnCaAl[Al2O7] with Ln = Tb, Sm

    NASA Astrophysics Data System (ADS)

    Peters, L.; Knorr, K.; Knapp, M.; Depmeier, W.

    2005-12-01

    The thermal expansion of gehlenite, Ca2Al[AlSiO7], (up to T=830 K), TbCaAl[Al2O7] (up to T=1100 K) and SmCaAl[Al2O7] (up to T=1024 K) has been determined. All compounds are of the melilite structure type with space group P{bar{4}}21m. Thermal expansion data were obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches Elektronen Synchrotron (DESY) in Hamburg (Germany). The thermal expansion coefficients for gehlenite were found to be: ?1=7.2(4)×10-6×K-1+3.6(7)×10-9? T×K-2 and ?3=15.0(1)×10-6×K-1. For TbCaAl[Al2O7] the respective values are: ?1=7.0(2)×10-6×K-1+2.0(2)×10-9? T×K-2 and ?3=8.5(2)×10-6×K-1+2.0(3)×10-9? T×K-2, and the thermal expansion coefficients for SmCaAl[Al2O7] are: ?1=6.9(2)×10-6×K-1+1.7(2)×10-9? T×K-2 and ?3=9.344(5)×10-6×K-1. The expansion mechanisms of the three compounds are explained in terms of structural trends obtained from Rietveld refinements of the crystal structures of the compounds against the powder diffraction patterns. No structural phase transitions have been observed. While gehlenite behaves like a ‘proper’ layer structure, the aluminates show increased framework structure behavior. This is most probably explained by stronger coulombic interactions between the tetrahedral conformation and the layer-bridging cations due to the coupled substitution (Ca2++Si4+) ( Ln 3++Al3+) in the melilite-type structure.

  14. Preparation and Thermoelectric Properties of YbAl3 Thermoelectric Materials with Excessive Al

    NASA Astrophysics Data System (ADS)

    He, Dan-qi; Zhao, Wen-Yu; Mu, Xin; Zhou, Hong-yu; Zhang, Qing-jie

    2015-01-01

    A method to prepare YbAl3 sample with an accurate stoichiometric ratio has been developed by a melting, quenching, annealing and spark plasma sintering (SPS) method. A series of YbAl3 thermoelectric materials with nominal compositions YbAl3+x (x = 0-0.3, ?x = 0.1) have been prepared using the method. We have explored the effects of the excessive Al on phase compositions, microstructure and transport properties. The quenched samples are composed of YbAl3, YbAl2, Yb, and Al. All the annealed samples are composed of main phase YbAl3 and a trace of Al; some annealed samples with x = 0 and x = 0.1 still contain a trace of YbAl2. The SPSed samples with x ? 0.1 are composed of single-phase YbAl3, though a trace of YbAl2 still occured in the SPSed sample with x = 0. The electrical conductivity, Seebeck coefficient, power factor, thermal conductivity and ZT values are first increased with increasing x in the range of 0-0.2 and then decreased when x > 0.2. These thermoelectric properties evolutions originate from the change of densities and chemical composition induced by the excessive Al. The highest ZT value reaches 0.28 at 300 K for the SPSed sample with x = 0.2.

  15. SCIENCE CAREER Al nanoclusters in coagulants and granulates: application

    E-print Network

    Wehrli, Bernhard

    aluminum hydroxide complexes with 1 nm diameter and 1­2 nm length. Al13 is a cluster of four Al trimers suitable for arsenic removal. The aluminum nanocl- usters Al13 (AlO4Al12(OH)24H2O12 7? ) and Al30 (Al2O8Al properties of aluminum nanoclusters and their efficiency for water treatment, particularly for arsenic

  16. Al Shabaab's Foreign Threat to Somalia

    Microsoft Academic Search

    David Shinn

    2011-01-01

    This article focuses on the threat to Somalia by al Shabaab (The Youth), an extremist organization that controls most of southern and central Somalia. It learned its strategy and tactics from al Qaeda and the Taliban and relies heavily on a relatively small number of foreign fighters, most of whom are Somalis with foreign passports from the large Somali diaspora.

  17. Freund et al. Mechanisms underlying differential expression

    E-print Network

    Boyer, Edmond

    Freund et al. - 1 - Mechanisms underlying differential expression of interleukin-8 in breast cancer cells Ariane Freund, Valérie Jolivel, Sébastien Durand, Nathalie Kersual, Dany Chalbos, Carine Chavey #12;Freund et al. - 2 - ABSTRACT We have recently reported that Interleukin-8 (IL-8) expression

  18. Quantitatively Probing the Al Distribution in Zeolites

    SciTech Connect

    Vjunov, Aleksei; Fulton, John L.; Huthwelker, Thomas; Pin, Sonia; Mei, Donghai; Schenter, Gregory K.; Govind, Niranjan; Camaioni, Donald M.; Hu, Jian Z.; Lercher, Johannes A.

    2014-06-11

    The degree of substitution of Si4+ by Al3+ in the oxygen-terminated tetrahedra (Al T-sites) of zeolites determines the concentration of ion-exchange and Brønsted acid sites. As the location of the tetrahedra and the associated subtle variations in bond angles influence the acid strength, quantitative information about Al T-sites in the framework is critical to rationalize catalytic properties and to design new catalysts. A quantitative analysis is reported that uses a combination of extended X-ray absorption fine structure (EXAFS) analysis and 27Al MAS NMR spectroscopy supported by DFT-based molecular dynamics simulations. To discriminate individual Al atoms, sets of ab initio EXAFS spectra for various T-sites are generated from DFT-based molecular dynamics simulations allowing quantitative treatment of the EXAFS single- and multiple-photoelectron scattering processes out to 3-4 atom shells surrounding the Al absorption center. It is observed that identical zeolite types show dramatically different Al-distributions. A preference of Al for T-sites that are part of one or more 4-member rings in the framework over those T-sites that are part of only 5- and 6-member rings in the HBEA150 sample has been determined from a combination of these methods. This work was supported by the U. S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  19. 76 FR 35938 - The Designation of Othman al-Ghamdi Also Known as Al Umairah al-Ghamdi, Also Known as Uthman al...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-20

    ...Known as Uthman Ahmad Uthman al-Ghamdi, Also Known as Othman Ahmed Othman al-Omirah as a Specially Designated Global Terrorist Pursuant to Section 1(b) of Executive Order 13224, as Amended Acting under the authority of and in accordance with...

  20. Diana Al-Hadid: Identity and Heritage

    ERIC Educational Resources Information Center

    Jungerberg, Tom; Smith, Anna; Borsh, Colleen

    2012-01-01

    Diana Al-Hadid's sculptures reflect the many locations, cultures, histories, and mythologies that have shaped her as an artist. In large-scale works which have the appearance of architectural ruins, Al-Hadid employs imagery drawn from many diverse interests including science and technology, history, and literature. She also incorporates images and…

  1. PROVE DI IMPATTO SU PANNELLI AL - NOMEX

    Microsoft Academic Search

    M. Giglio; A. Manes

    Sommario Il presente lavoro descrive prove preliminari di impatto a bassa velocità effettuate su un pannello sandwich (Al-Nomex) utilizzato estesamente su fusoliere di elicottero. Non essendoci una normativa vigente sull'intero processo di prova, è stato eseguito un ampio studio preliminare al fine di valutare le possibili soluzioni utilizzabili. E' stata quindi realizzata una struttura di prova dedicata composta da una

  2. Durability Assessment of TiAl Alloys

    NASA Technical Reports Server (NTRS)

    Draper, Susan L.; Lerch, Bradley A.

    2008-01-01

    The durability of TiAl is a prime concern for the implementation of TiAl into aerospace engines. Two durability issues, the effect of high temperature exposure on mechanical properties and impact resistance, have been investigated and the results are summarized in this paper. Exposure to elevated temperatures has been shown to be detrimental to the room temperature ductility of gamma alloys with the most likely mechanisms being the ingress of interstitials from the surface. Fluorine ion implantation has been shown to improve the oxidation resistance of gamma alloys, and ideally it could also improve the environmental embrittlement of high Nb content TiAl alloys. The effect of F ion implantation on the surface oxidation and embrittlement of a third generation, high Nb content TiAl alloy (Ti-45Al-5Nb-B-C) were investigated. Additionally, the ballistic impact resistance of a variety of gamma alloys, including Ti-48Al-2Cr- 2Nb, Ti-47Al-2Cr-2Nb, ABB-2, ABB-23, NCG359E, 95A and Ti-45Al-5Nb-B-C was accessed. Differences in the ballistic impact properties of the various alloys will be discussed, particularly with respect to their manufacturing process, microstructure, and tensile properties.

  3. Energetics of Al13 Keggin cluster compounds

    PubMed Central

    Armstrong, Christopher R.; Casey, William H.; Navrotsky, Alexandra

    2011-01-01

    The ?-Al13 Keggin aluminum hydroxide clusters are essential models in establishing molecular pathways for geochemical reactions. Enthalpies of formation are reported for two salts of aluminum centered ?-Keggin clusters, Al13 selenate, (Na(AlO4)Al12(OH)24(SeO4)4•12H2O) and Al13 sulfate, (NaAlO4Al12(OH)24(SO4)4•12H2O). The measured enthalpies of solution, ?Hsol, at 28?°C in 5 N HCl for the ?-Al13 selenate and sulfate are ?924.57 (± 3.83) and ?944.30 ( ± 5.66) kJ·mol-1, respectively. The enthalpies of formation from the elements, ?Hf,el, for Al13 selenate and sulfate are ?19,656.35 ( ± 67.30) kJ·mol-1, and ?20,892.39 ( ± 70.01) kJ·mol-1, respectively. In addition, ?Hf,el for sodium selenate decahydrate was calculated using data from high temperature oxide melt solution calorimetry measurements: ?4,006.39 ( ± 11.91) kJ·mol-1. The formation of both ?-Al13 Keggin cluster compounds is exothermic from oxide-based components but energetically unfavorable with respect to a gibbsite-based assemblage. To understand the relative affinity of the ?-Keggin clusters for selenate and sulfate, the enthalpy associated with two S-Se exchange reactions was calculated. In the solid state, selenium is favored in the Al13 compound relative to the binary chalcogenate, while in 5 N HCl, sulfur is energetically favored in the cluster compound compared to the aqueous solution. This contribution represents the first thermodynamic study of ?-Al13 cluster compounds and establishes a method for other such molecules, including the substituted versions that have been created for kinetic studies. Underscoring the importance of ?-Al13 clusters in natural and anthropogenic systems, these data provide conclusive thermodynamic evidence that the Al13 Keggin cluster is a crucial intermediate species in the formation pathway from aqueous aluminum monomers to aluminum hydroxide precipitates. PMID:21852572

  4. NiAl alloys for structural uses

    NASA Technical Reports Server (NTRS)

    Koss, D. A.

    1991-01-01

    Alloys based on the intermetallic compound NiAl are of technological interest as high temperature structural alloys. These alloys possess a relatively low density, high melting temperature, good thermal conductivity, and (usually) good oxidation resistance. However, NiAl and NiAl-base alloys suffer from poor fracture resistance at low temperatures as well as inadequate creep strength at elevated temperatures. This research program explored macroalloying additions to NiAl-base alloys in order to identify possible alloying and processing routes which promote both low temperature fracture toughness and high temperature strength. Initial results from the study examined the additions of Fe, Co, and Hf on the microstructure, deformation, and fracture resistance of NiAl-based alloys. Of significance were the observations that the presence of the gamma-prime phase, based on Ni3Al, could enhance the fracture resistance if the gamma-prime were present as a continuous grain boundary film or 'necklace'; and the Ni-35Al-20Fe alloy was ductile in ribbon form despite a microstructure consisting solely of the B2 beta phase based on NiAl. The ductility inherent in the Ni-35Al-20Fe alloy was explored further in subsequent studies. Those results confirm the presence of ductility in the Ni-35Al-20Fe alloy after rapid cooling from 750 - 1000 C. However exposure at 550 C caused embrittlement; this was associated with an age-hardening reaction caused by the formation of Fe-rich precipitates. In contrast, to the Ni-35Al-20Fe alloy, exploratory research indicated that compositions in the range of Ni-35Al-12Fe retain the ordered B2 structure of NiAl, are ductile, and do not age-harden or embrittle after thermal exposure. Thus, our recent efforts have focused on the behavior of the Ni-35Al-12Fe alloy. A second parallel effort initiated in this program was to use an alternate processing technique, mechanical alloying, to improve the properties of NiAl-alloys. Mechanical alloying in the conventional sense requires ductile powder particles which, through a cold welding and fracture process, can be dispersion strengthened by submicron-sized oxide particles. Using both the Ni-35Al-Fe alloys to contain approx. 1 v/o Y2O3. Preliminary results indicate that mechanically alloyed and extruded NiAl-Fe + Y2O3 alloys when heat treated to a grain-coarsened condition, exhibit improved creep resistance at 1000 C when compared to NiAl; oxidation resistance comparable to NiAl; and fracture toughness values a factor of three better than NiAl. As a result of the research initiated on this NASA program, a subsequent project with support from Inco Alloys International is underway.

  5. Corrosion Studies of 2195 Al-Li Alloy and 2219 Al Alloy with Differing Surface Treatments

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1998-01-01

    Corrosion studies of 2195 Al-Li and 2219 Al alloys have been conducted using the scanning reference electrode technique (SRET) and the polarization resistance (PR) technique. The SRET was used to study corrosion mechanisms, while corrosion rate measurements were studied with the PR technique. Plates of Al203 blasted, soda blasted and conversion coated 2219 Al were coated with Deft primer and the corrosion rates studied with the EIS technique. Results from all of these studies are presented.

  6. High temperature creep behaviour of Al-rich Ti-Al alloys

    NASA Astrophysics Data System (ADS)

    Sturm, D.; Heilmaier, M.; Saage, H.; Aguilar, J.; Schmitz, G. J.; Drevermann, A.; Palm, M.; Stein, F.; Engberding, N.; Kelm, K.; Irsen, S.

    2010-07-01

    Compared to Ti-rich ?-TiAl-based alloys Al-rich Ti-Al alloys offer an additional reduction of in density and a better oxidation resistance which are both due to the increased Al content. Polycrystalline material was manufactured by centrifugal casting. Microstructural characterization was carried out employing light-optical, scanning and transmission electron microscopy and XRD analyses. The high temperature creep of two binary alloys, namely Al60Ti40 and Al62Ti38 was comparatively assessed with compression tests at constant true stress in a temperature range between 1173 and 1323 K in air. The alloys were tested in the cast condition (containing various amounts of the metastable phases Al5Ti3 and h-Al2Ti) and after annealing at 1223 K for 200 h which produced (thermodynamically stable) lamellar ?-TiAl + r-Al2Ti microstructures. In general, already the as-cast alloys exhibit a reasonable creep resistance at 1173 K. Compared with Al60Ti40, both, the as-cast and the annealed Al62Ti38 alloy exhibit better creep resistance up to 1323 K which can be rationalized by the reduced lamella spacing. The assessment of creep tests conducted at identical stress levels and varying temperatures yielded apparent activation energies for creep of Q = 430 kJ/mol for the annealed Al60Ti40 alloy and of Q = 383 kJ/mol for the annealed Al62Ti38 material. The latter coincides well with that of Al diffusion in ?-TiAl, whereas the former can be rationalized by the instability of the microstructure containing metastable phases.

  7. Dry sliding wear of Al alloy 2024Al 20 3 particle metal matrix composites

    Microsoft Academic Search

    Manish Narayan; M. K. Surappa; B. N. Pramila Bai

    1995-01-01

    In the present investigation, Al 2024-15vol.%Al203 particulate (average size, 18 ?m) composites were fabricated using the liquid metallurgy route. The wear and friction characteristics of AI alloy 2024 and Al 2024-15vol.%Al203p composite in the as-extruded and peak-aged conditions were studied using a pin-on-disc machine (with a steel disc as the counterface material). The worn surfaces, subsurfaces and the debris were

  8. Site preferences of indium impurity atoms in intermetallics having Al3Ti and Al3Zr crystal structures

    E-print Network

    Collins, Gary S.

    Site preferences of indium impurity atoms in intermetallics having Al3Ti and Al3Zr crystal · Indium was doped in samples of Al3V and Al3Ti (Al3Ti structure) and Al3Zr (Al3Zr structure) by arc-melting; doping at 10 ppb level. · Inequivalent Al-sites occupied by indium solutes were identified by measuring

  9. Reassessment of Al-Ce and Al-Nd Binary Systems Supported by Critical Experiments and First-Principles

    E-print Network

    Widom, Michael

    Reassessment of Al-Ce and Al-Nd Binary Systems Supported by Critical Experiments and First The present study reinvestigates the Al-Ce and Al-Nd phase diagrams and reoptimizes their thermody- namics results and theoretical calculations show that Al2Nd (or Al2Ce) should be treated as a stoichiometric

  10. APRENDER A VIVIR EN UN MUNDO COMPLEJO. ESCUCHANDO AL GRAN MAESTRO EDGAR MORIN

    Microsoft Academic Search

    Sheina Lee Leoni Handel

    2010-01-01

    En este artículo se explicará cómo hacer frente en época actual a una sociedad muy compleja, donde los fenómenos sociales, políticos, económicos, y culturales se dan indefectiblemente unidos, de tal forma que para poder comprenderlos racional y científicamente habrá que tener en cuenta el contexto particular y planetario en donde estos surgen .

  11. Atomistic Modeling of RuAl and (RuNi) Al Alloys

    NASA Technical Reports Server (NTRS)

    Gargano, Pablo; Mosca, Hugo; Bozzolo, Guillermo; Noebe, Ronald D.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Atomistic modeling of RuAl and RuAlNi alloys, using the BFS (Bozzolo-Ferrante-Smith) method for alloys is performed. The lattice parameter and energy of formation of B2 RuAl as a function of stoichiometry and the lattice parameter of (Ru(sub 50-x)Ni(sub x)Al(sub 50)) alloys as a function of Ni concentration are computed. BFS based Monte Carlo simulations indicate that compositions close to Ru25Ni25Al50 are single phase with no obvious evidence of a miscibility gap and separation of the individual B2 phases.

  12. High Al-content AlGaN\\/GaN MODFETs for ultrahigh performance

    Microsoft Academic Search

    Y.-F. Wu; B. P. Keller; P. Fini; S. Keller; T. J. Jenkins; L. T. Kehias; S. P. Denbaars; U. K. Mishra

    1998-01-01

    The use of an AlGaN layer with high Al mole-fraction is proposed to increase the equivalent figures of merit of the AlGaN\\/GaN MODFET structure. It is shown that the room temperature mobility has little degradation with increasing Al mole-fraction up to 50%. 0.7-?m gate-length Al0.5Ga0.5N\\/GaN MODFETs by optical lithography exhibit a current density of 1 A\\/mm and three-terminal breakdown voltages

  13. AlGaN/GaN/AlN quantum-well field-effect transistors with highly resistive AlN epilayers

    E-print Network

    Jiang, Hongxing

    of the AlGaN/GaN/AlN QW-FET structure used in this study. A Si -doping level of 4.5 10AlGaN/GaN/AlN quantum-well field-effect transistors with highly resistive AlN epilayers Z. Y. Fana 66506-2601 Received 23 November 2005; accepted 5 January 2006; published online 16 February 2006 AlGaN/GaN

  14. Single-phase interdiffusion in the B2 type intermetallic compounds NiAl, CoAl and FeAl

    Microsoft Academic Search

    Ryusuke Nakamura; Koichi Takasawa; Yoshihiro Yamazaki; Yoshiaki Iijima

    2002-01-01

    Interdiffusion coefficients, D, in the B2 type NiAl, CoAl and FeAl phases have been determined by single phase diffusion couples over a wide temperature range from 1073 to 1773 K. The value of D in the NiAl and CoAl phases shows a minimum at about 47 at.% Al deviating slightly from the stoichiometric composition, while the value of D in

  15. Solar-blind ultraviolet AlInN/AlGaN distributed Bragg reflectors

    NASA Astrophysics Data System (ADS)

    Zhang, Lili; Dong, Kexiu; Chen, Dunjun; Liu, Yanli; Xue, Junjun; Lu, Hai; Zhang, Rong; Zheng, Youdou

    2013-06-01

    A 13.5-pair Al0.98In0.02N/Al0.77Ga0.23N distributed Bragg reflector (DBR) was grown by molecular beam epitaxy on an AlN template substrate. The DBR exhibited a peak reflectivity of 83.9% at 246 nm within the deep solar-blind ultraviolet region and a stopband width of 18 nm. The average refractive index contrast for the DBR was 9.25% at 246 nm, which is relatively high compared with that of a traditional Al(Ga)N/(Al)GaN DBR. Simulated results indicated that a 25.5-pair Al0.98In0.02N/Al0.77Ga0.23N DBR will provide a reflectivity higher than 99% and a 19 nm wide stopband with a center wavelength of 246 nm.

  16. Optical characterization of Al- and N-polar AlN waveguides for integrated optics

    NASA Astrophysics Data System (ADS)

    Rigler, Martin; Buh, Jože; Hoffmann, Marc P.; Kirste, Ronny; Bobea, Milena; Mita, Seiji; Gerhold, Michael D.; Collazo, Ramon; Sitar, Zlatko; Zgonik, Marko

    2015-04-01

    Dispersion of the extraordinary and ordinary refractive indices of Al- and N-polar AlN waveguides is measured by multiple angle-of-incidence and spectroscopic ellipsometry techniques. The polarity-controlled AlN layers are grown by metal–organic chemical vapor deposition on (0001)-sapphire substrates. Taking into consideration the different surface morphologies of the Al- and N-polar AlN waveguides, we propose two optical models to describe the measured ellipsometry data. The results indicate that there is no difference between the refractive indices of the AlN grown in opposite directions, which confirms the potential of the AlN lateral polar structures for use in nonlinear optical applications based on quasi phase matching.

  17. High quality AlGaN grown on ELO AlN/sapphire templates

    NASA Astrophysics Data System (ADS)

    Zeimer, U.; Kueller, V.; Knauer, A.; Mogilatenko, A.; Weyers, M.; Kneissl, M.

    2013-08-01

    The defect structure and the homogeneity of 1-3 µm thick AlxGa1-xN layers grown on epitaxially laterally overgrown (ELO) AlN on patterned AlN/sapphire templates have been investigated in dependence on the miscut direction of the c-plane sapphire substrates, the etching depth into the sapphire and the Al concentration. It was found that shallowly etched AlN/sapphire templates with a 0.25° miscut toward the a-plane provide a smooth surface of ELO AlN and therefore a good Al homogeneity in the overgrown Al0.8Ga0.2N layer. The threading dislocation density in these layers is as low as 5×108 cm-2.

  18. Spin reorientation in Al/Metglas 2605S2/Al trilayers induced by magnetoelastic effect

    NASA Astrophysics Data System (ADS)

    Moscon, P. S.; Passamani, E. C.; Larica, C.; Takeuchi, A. Y.; Sánchez, F. H.; Zélis, P. Mendoza; Baggio-Saitovitch, Elisa

    2008-09-01

    Mössbauer spectroscopy, in a broad temperature interval of 12-425 K, has been applied to investigate the spin reorientation dynamics caused by the temperature induced magnetoelastic effect on Al(x ?m)/Metglas 2605S2 (20 ?m)/Al(x ?m) trilayers (x =0; 2.5; 5 and 20). It was found that the angle between the average sample magnetization and gamma ray direction (perpendicular to the sample plane) depends on the Al layer thickness. For temperatures smaller than 260 K, saturation of spin reorientation, which can be controlled by adjusting the Al thickness, was reached for Al thicknesses larger than and equal to 5 ?m. For a 20 ?m Al thickness, changes in the F57e atom spin and charge densities have also been observed. A simple spin model has been proposed to describe qualitatively the spin reorientation effect as well as the influence of the Al thickness on the spin reorientation sensitivity.

  19. Ni{sub 3}Al aluminide alloys

    SciTech Connect

    Liu, C.T.

    1993-10-01

    This paper provides a brief review of the recent progress in research and development of Ni{sub 3}Al and its alloys. Emphasis has been placed on understanding low ductility and brittle fracture of Ni{sub 3}Al alloys at ambient and elevated temperatures. Recent studies have resulted in identifying both intrinsic and extrinsic factors governing the fracture behavior of Ni{sub 3}Al alloys. Parallel efforts on alloy design using physical metallurgy principles have led to properties for structural use. Industrial interest in these alloys is high, and examples of industrial involvement in processing and utilization of these alloys are briefly mentioned.

  20. Crack-free thick AlGaN grown on sapphire using AlN/AlGaN superlattices for strain management

    NASA Astrophysics Data System (ADS)

    Zhang, J. P.; Wang, H. M.; Gaevski, M. E.; Chen, C. Q.; Fareed, Q.; Yang, J. W.; Simin, G.; Khan, M. Asif

    2002-05-01

    We report on an AlN/AlGaN superlattice approach to grow high-Al-content thick n+-AlGaN layers over c-plane sapphire substrates. Insertion of a set of AlN/AlGaN superlattices is shown to significantly reduce the biaxial tensile strain, thereby resulting in 3-?m-thick, crack-free Al0.2Ga0.8N layers. These high-quality, low-sheet-resistive layers are of key importance to avoid current crowding in quaternary AlInGaN multiple-quantum-well deep-ultraviolet light-emitting diodes over sapphire substrates.

  1. Glial cells in ALS: the missing link?

    PubMed

    Raibon, Elsa; Todd, Lisa Marie; Möller, Thomas

    2008-08-01

    Amyotrophic lateral sclerosis (ALS) was initially known as Charcot's sclerosis, named after the French neurobiologist and physician Jean-Martin Charcot who first described this type of muscular atrophy in the early nineteenth century. In the United States, ALS became widely known as Lou Gehrig's disease after the famous baseball player who succumbed to the disease in the late 1930s. Currently, ALS is the most common motor neuron disease, with a worldwide incidence of 8 cases per 100,000 population per year. Familial forms constitute approximately 5% to 10% of all cases. Onset increases with age, with a peak in the seventh decade and a slight preponderance (relative risk, 1.3-1.5) among men compared with women. Rapid progression of motor neuron loss leads to death an average of 3 to 5 years after symptom onset. The cause of ALS remains unknown and there is still no curative therapy. PMID:18625409

  2. US 20080226134Al (19) United States

    E-print Network

    Stetten, George

    Classi?cation CONTROLLER (51) Int- Cl (76) Inventors: George DeWitt STETTEN,Pittsburgh, PA (US); Roberta/0226134 A1 STETTEN et al. (43) Pub. Date: Sep. 18, 2008 (54) FINGERTIP VISUAL HAPTIC SENSOR Publication

  3. Everyday Life with ALS: A Practical Guide

    MedlinePLUS

    ... years ago. ALS: Maintaining Mobility, A Guide to Physical Therapy and Occupational Therapy proved to be an invaluable ... several approaches to communication in ways other than traditional speech. Weakness can limit your ability to accomplish ...

  4. Western Baldwin County, AL Grid Interconnection Project

    SciTech Connect

    Thomas DeBell

    2011-09-30

    The Objective of this Project was to provide an additional supply of electricity to the affected portions of Baldwin County, AL through the purchase, installation, and operation of certain substation equipment.

  5. Half life of /sup 26/Al

    SciTech Connect

    Norris, T.L.; Gancarz, A.J.; Rokop, D.J.; Thomas, K.W.

    1983-01-01

    The half-life of /sup 26/Al has been redetermined because of suggestions of an error in the accepted value based on its use in calculating /sup 21/Ne production rates from cosmic rays in meteorites. Two solutions of /sup 26/Al were analyzed for the specific radioactivity and mass spectrometric determination of the /sup 26/Al concentration. The half-life obtained for /sup 26/Al was 7.05 x 10/sup 5/ years +- 3.7% at the two sigma level. This is identical to the accepted value of 7.16 x 10/sup 5/ years and indicates that problems with the /sup 21/Ne production rate is not due to an erroneous half-life.

  6. Innovative Al Damascene Process for Nanoscale Interconnects

    Microsoft Academic Search

    Kyung-In Choi; Sung-Ho Han; Sera Yun; Dae-Yong Kim; Jong Won Hong; Sang Woo Lee; Byung Hee Kim; Sung-Tae Kim; U-In Chung; Joo-Tae Moon; Byung-Il Ryu

    2006-01-01

    A novel chemical vapor deposition (CVD)-Al technique of ``bottom-up growth'' was developed using methylpyrrolidine alane as a precursor and a (PVD)-TiN\\/CVD-TiN stacked barrier in a damascene structure. Poor step coverage of PVD-TiN caused an absence of PVD-TiN at the bottom of trenches, resulting in selective Al growth. The new method filled a 40-nm-wide trench (aspect ratio = 7.5) completely and

  7. Magnetism of Al-Mn quasicrystals

    SciTech Connect

    Liu, F.; Khanna, S.N.; Magaud, L.; Jena, P. (Physics Department, Virginia Commonwealth University, Richmond, Virginia 23284-2000 (United States)); de Coulon, V.; Reuse, F. (Institut de Physique Experimentale, Ecole Polytechnique Federale de Lausanne, PHB-Ecublens, Lausanne (Switzerland)); Jaswal, S.S.; He, X. (Department of Physics and Astronomy, The University of Nebraska-Lincoln, 260 Behlen Laboratory, Lincoln, Nebraska 68588-0111 (United States)); Cyrot-Lackman, F. (Laboratoire d'Etudes des Proprietes Electroniques des Solides, Centre National de la Recherche Scientifique, Boite Postale 166X, 38042 Grenoble, CEDEX France ( ))

    1993-07-01

    The effect of symmetry and concentration of Mn on the magnetism of Al-Mn quasicrystals has been investigated through self-consistent density-functional calculations using molecular clusters and supercell band-structure schemes. A single Mn atom surrounded by 54 Al atoms in an icosahedral or a cuboctahedral structure is found to be nonmagnetic. However, as the Mn concentration is increased, moments develop on Mn sites whose magnitude and coupling depend on their location.

  8. 17th Annual ALS Users' Association Meeting

    SciTech Connect

    Robinson, Art; Tamura, Lori

    2004-11-29

    It's not exactly Russian roulette, but scheduling October events outdoors is not risk-free, even in usually sunny California. An overflow crowd of more than 400 registered users, ALS staff, and vendors enjoyed a full indoor program featuring science highlights and workshops spread over two and a half days from October 18 to October 20. However, a major storm, heralding the onset of the San Francisco Bay Area rainy season, posed a few weather challenges for the events on the ALS patio.

  9. Continuous germanene layer on al(111).

    PubMed

    Derivaz, Mickael; Dentel, Didier; Stephan, Régis; Hanf, Marie-Christine; Mehdaoui, Ahmed; Sonnet, Philippe; Pirri, Carmelo

    2015-04-01

    Germanene, a 2D honeycomb structure similar to silicene, has been fabricated on Al(111). The 2D germanene layer covers uniformly the substrate with a large coherence over the Al(111) surface atomic plane. It is characterized by a (3 × 3) superstructure with respect to the substrate lattice, shown by low energy electron diffraction and scanning tunnelling microscopy. First-principles calculations indicate that the Ge atoms accommodate in a very regular atomic configuration with a buckled conformation. PMID:25802988

  10. Structure of decagonal Al-Ni-Rh.

    PubMed

    Logvinovich, Dmitry; Simonov, Arkadiy; Steurer, Walter

    2014-08-01

    The crystal structure of the decagonal phase in the system Al-Ni-Rh (d-Al-Ni-Rh) was analyzed in the five-dimensional embedding approach based on single-crystal synchrotron X-ray diffraction data. The structure can be described as a quasiperiodic packing of partially overlapping decagonal and pentagonal columnar clusters with ??21?Å diameter and ??4?Å period along the tenfold axis. PMID:25080252

  11. Effects of Al on nitrogen (NH

    Microsoft Academic Search

    W. G. Keltjens; P. S. R. van Ulden

    1987-01-01

    After growth for 17 to 36 days on nutrient solutions with NH4NO3 as nitrogen source (pH 4.2) dry matter of sorghum genotype SC0283 was much less affected by Al (1.5 and 3.0 ppm) than that\\u000a of genotype NB9040.\\u000a \\u000a In the absence of Al both cultivars released protons into the nutrient solution as a result of an excess of cationic nutrients

  12. Interband optical properties of Ni3Al

    Microsoft Academic Search

    M. A. Khan; Arti Kashyap; A. K. Solanki; T. Nautiyal; S. Auluck

    1993-01-01

    We present calculations of interband optical conductivity of the compound Ni3Al using the linear-muffin-tin-orbital method. Calculations are performed using constant matrix elements and calculated matrix elements. We find that matrix elements play a significant role in influencing the magnitude of optical conductivity sigma(omega) and the position of peaks. Since Ni3Al is weakly ferromagnetic (magnetic moment equal to 0.31muB per unit

  13. Magnetic Properties of Disordered Fe3Al

    NASA Astrophysics Data System (ADS)

    Nehra, J.; Kabra, K.; Jani, S.; Ranjith, P. M.; Lakshmi, N.; Venugopalan, K.

    2011-07-01

    The magnetic properties of Fe3Al powders prepared by filing the ingot in both as-filed and annealed form are studied. Results of Mössbauer, X-ray diffraction and DC magnetization studies show that the magnetic properties are modified due to formation of non-magnetic Fe3AlC0.5 phase due to C intercalated on filing. The hyperfine fields obtained are explained in terms of nearest and next nearest neighbor configurations of 57Fe.

  14. Interdiffusion in the Mg-Al System and Intrinsic Diffusion in ?-Mg2Al3

    NASA Astrophysics Data System (ADS)

    Brennan, Sarah; Bermudez, Katrina; Kulkarni, Nagraj S.; Sohn, Yongho

    2012-11-01

    Solid-to-solid diffusion couples were assembled and annealed to examine the diffusion between pure Mg (99.96 pct) and Al (99.999 pct). Diffusion anneals were carried out at 573 K, 623 K and 673 K (300 °C, 350 °C and 400 °C) for 720, 360, and 240 hours, respectively. Optical and scanning electron microscopes were used to identify the formation of the intermetallic phases, ?-Mg17Al12, and ?-Mg2Al3, as well as the absence of the ?-Mg23Al30 in the diffusion couples. The thicknesses of the ?-Mg17Al12 and ?-Mg2Al3 phases were measured and the parabolic growth constants were calculated to determine the activation energies for growth. Concentration profiles were determined with electron microprobe analysis using pure elemental standards. Composition-dependent interdiffusion coefficients in Mg-solid solution, ?-Mg17Al12, ?-Mg2Al3, and Al-solid solutions were calculated based on the Boltzmann-Matano analysis. Integrated and average effective interdiffusion coefficients for each phase were also calculated, and the magnitude was the highest for the ?-Mg2Al3 phase, followed by ?-Mg17Al12, Al-solid solution, and Mg-solid solution. Intrinsic diffusion coefficients based on Huemann's analysis ( e.g., marker plane) were determined for the ~ Mg-62 at. pct Al in the ?-Mg2Al3 phase. Activation energies and the pre-exponential factors for the interdiffusion and intrinsic diffusion coefficients were calculated for the temperature range examined. The ?-Mg2Al3 phase was found to have the lowest activation energies for growth and interdiffusion among all four phases studied. At the marker location in the ?-Mg2Al3 phase, the intrinsic diffusion of Al was found to be faster than that of Mg. Extrapolations of the impurity diffusion coefficients in the terminal solid solutions were made and compared with the available self-diffusion and impurity diffusion data from the literature. Thermodynamic factor, tracer diffusion coefficients, and atomic mobilities at the marker plane composition were approximated using the available literature values of Mg activity in the ?-Mg2Al3 phase.

  15. Modeling of precipitation in Al alloys

    SciTech Connect

    Asta, M.; Foiles, S.M.; Wolfer, W.G. [Sandia National Labs., Livermore, CA (United States)] [and others

    1996-10-01

    Objective was the development of a computational model of precipitation from a supersaturated alloy solid solution. The model is based on the formalism of chemical-reaction-rate theory combined with classical descriptions of precipitate thermodynamic properties and a mean-field treatment of diffusion-limited growht and coarsening. For the case of precipitation of Al{sub 3}Sc in supersaturated Al-Sc alloys, it is demonstrated how the model can be used to calculate number densities and size distributions of precipitates as a function of aging time and temperature, including effects of continuous cooling and thermally generated point defects. Application of the model to a specific alloy system requires knowledge of diffusion data, point defect energetics, and thermodynamic properties for bulk phases and interphase interfaces. For interfaces and point defects, thermodynamic data can be difficult to measure and reliable values of defect free energies are often unavailable. For this reason, part of the efforts were devoted to applying semiempirical and first-principles atomistic techniques to the calculation of interfacial and point-defect thermodynamic properties. This report discusses applications for interphase interfaces in the Al-Ag, Al-Sc, and Al-Li alloy systems. We also describe atomistic work aimed at understanding the energetics of vacancy clusters in Al. These clusters serve as sinks for isolated vacancies during aging and their growth can lead to more complex defects, such as dislocation loops, that act as heterogeneous nucleation sites.

  16. Differential corticospinal tract degeneration in homozygous ‘D90A’ SOD-1 ALS and sporadic ALS

    PubMed Central

    Blain, C R V; Brunton, S; Williams, V C; Leemans, A; Turner, M R; Andersen, P M; Catani, M; Stanton, B R; Ganesalingham, J; Jones, D K; Williams, S C R; Leigh, P N

    2011-01-01

    Background The homogeneous genotype and stereotyped phenotype of a unique familial form of amyotrophic lateral sclerosis (ALS) (patients homozygous for aspartate-to-alanine mutations in codon 90 (homD90A) superoxide dismutase 1) provides an ideal model for studying genotype/phenotype interactions and pathological features compared with heterogeneous apparently sporadic ALS. The authors aimed to use diffusion tensor tractography to quantify and compare changes in the intracerebral corticospinal tracts of patients with both forms of ALS, building on previous work using whole-brain voxelwise group analysis. Method 21 sporadic ALS patients, seven homD90A patients and 20 healthy controls underwent 1.5?T diffusion tensor MRI. Patients were assessed using ‘upper motor neuron burden,’ El Escorial and ALSFR-R scales. The intracranial corticospinal tract was assessed using diffusion tensor tractography measures of fractional anisotropy (FA), mean diffusivity, and radial and axial diffusivity obtained from its entire length. Results Corticospinal tract FA was reduced in sporadic ALS patients compared with both homD90A ALS patients and controls. The diffusion measures in sporadic ALS patients were consistent with anterograde (Wallerian) degeneration of the corticospinal tracts. In sporadic ALS, corticospinal tract FA was related to clinical measures. Despite a similar degree of clinical upper motor neuron dysfunction and disability in homD90A ALS patients compared with sporadic ALS, there were no abnormalities in corticospinal tract diffusion measures compared with controls. Conclusions Diffusion tensor tractography has shown axonal degeneration within the intracerebral portion of the corticospinal tract in sporadic ALS patients, but not those with a homogeneous form of familial ALS. This suggests significant genotypic influences on the phenotype of ALS and may provide clues to slower progression of disease in homD90A patients. PMID:21515558

  17. OVERVIEW NO. 136 DIFFUSION IN THE TiAl SYSTEM

    E-print Network

    Mishin, Yuri

    . Keywords: Intermetallic compounds; Diusion; Radio-tracer method; Theory and modeling 1. INTRODUCTION Intermetallic compounds of the Ti±Al system and alloys based on such compounds are materials of rapidly growing in a-Ti(Al), b-Ti(Al), and intermetallic phases a2-Ti3Al and g-TiAl, are summarized. The results

  18. Optical microcavities and enhanced electroluminescence from electroformed Al-Al2O3-Ag diodes

    NASA Astrophysics Data System (ADS)

    Hickmott, T. W.

    2013-12-01

    Electroluminescence (EL) and electron emission into vacuum (EM) occur when a non-destructive dielectric breakdown of Al-Al2O3-Ag diodes, electroforming, results in the development of a filamentary region in which current-voltage (I-V) characteristics exhibit voltage-controlled negative resistance. The temperature dependence of I-V curves, EM, and, particularly, EL of Al-Al2O3-Ag diodes with anodic Al2O3 thicknesses between 12 nm and 30 nm, has been studied. Two filters, a long-pass (LP) filter with transmission of photons with energies less than 3.0 eV and a short-pass (SP) filter with photon transmission between 3.0 and 4.0 eV, have been used to characterize EL. The voltage threshold for EL with the LP filter, VLP, is ˜1.5 V. VLP is nearly independent of Al2O3 thickness and of temperature and is 0.3-0.6 V less than the threshold voltage for EL for the SP filter, VSP. EL intensity is primarily between 1.8 and 3.0 eV when the bias voltage, VS ? 7 V. EL in the thinnest diodes is enhanced compared to EL in thicker diodes. For increasing VS, for diodes with the smallest Al2O3 thicknesses, there is a maximum EL intensity, LMX, at a voltage, VLMX, followed by a decrease to a plateau. LMX and EL intensity at 4.0 V in the plateau region depend exponentially on Al2O3 thickness. The ratio of LMX at 295 K for a diode with 12 nm of Al2O3 to LMX for a diode with 25 nm of Al2O3 is ˜140. The ratio of EL intensity with the LP filter to EL intensity with the SP filter, LP/SP, varies between ˜3 and ˜35; it depends on Al2O3 thickness and VS. Enhanced EL is attributed to the increase of the spontaneous emission rate of a dipole in a non-resonant optical microcavity. EL photons interact with the Ag and Al films to create surface plasmon polaritons (SPPs) at the metal-Al2O3 interfaces. SPPs generate large electromagnetic fields in the filamentary region of the electroformed Al-Al2O3-Ag diode, which then acts as an optical microcavity. A model is proposed for electronic processes in electroformed Al-Al2O3-Ag diodes.

  19. 77 FR 73732 - In the Matter of the Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ...Front, Jabhat al-Nusrah, Jabhet al-Nusra, The Victory Front, Al Nusrah Front...aka Jabhat al-Nusrah, aka Jabhet al-Nusra, aka The Victory Front, aka Al...Front, Jabhat al-Nusrah, Jabhet al-Nusra, The Victory Front, Al Nusrah...

  20. Comment on ``A new interpretation of Weimer et al.'s solar wind propagation delay technique'' by Bargatze et al.

    NASA Astrophysics Data System (ADS)

    Haaland, S.; Paschmann, G.; Sonnerup, B. U. Ã.-.

    2006-06-01

    In a recent article, Bargatze et al. (2005) have identified why the implementation of the minimum variance analysis (MVAB) by Weimer et al. (2003), even though based on an erroneous variance matrix, has been successful in estimating the orientation of the "phase fronts" and the resulting propagation delays of the interplanetary magnetic field (IMF). They recommend further testing of the Weimer analysis as a space weather forecasting tool. In this comment we stress that the Weimer et al. implementation of MVAB closely mimics the results of a well-known version of MVAB that is constrained by the condition that the average field along the phase front normals is zero. This version of MVAB starts from the correct variance matrix, whereas the Weimer analysis is based on an unphysical matrix resulting from a programming error. We recommend that the constrained MVAB, originally developed by Sonnerup and Cahill (1968) and later recast into a more convenient form by A.V. Khrabrov be used instead. The Khrabrov method, which we refer to as MVAB-0, has been tested at the Earth's magnetopause by Sonnerup and Scheible (1998) and more recently by Haaland et al. (2004) and Sonnerup et al. (2004).

  1. Theoretical studies of Ni/sub 3/Al and NiAl with impurities

    SciTech Connect

    Chen, S.P.; Voter, A.F.; Boring, A.M.; Albers, R.C.; Hay, P.J.

    1988-01-01

    Intermetallic compound has been extensively studied because of their superior properties in strength, low creep rate, and high melting point. But most of the systems have room temperature ductility problems, like Ll/sub 2/ and B2 compounds. Both Ll/sub 2/ Ni/sub 3/Al and B2 NiAl exhibit intergranular fracture mode. Understanding grain boundaries in these materials is of particular importance since intergranular fracture limits the applicability of these otherwise promising material. In an effort trying to understand the fracture mechanism, we have used embedded atom potentials to study the properties of Ni/sub 3/Al and NiAl. We also consider the effect of boron, sulfur, and nickel segregation on the strength of grain boundaries in Ni/sub 3/Al and NiAl. 22 refs., 2 figs.

  2. Analog resistive switching behavior of Al/Nb2O5/Al device

    NASA Astrophysics Data System (ADS)

    Mähne, H.; Wylezich, H.; Hanzig, F.; Slesazeck, S.; Rafaja, D.; Mikolajick, T.

    2014-10-01

    Resistive switching effects in metal–insulator–metal (MIM) structures are strongly influenced by the electrode materials. In this work a platinum-free symmetric Al/Nb2O5/Al device is compared to a device with platinum bottom electrode. For the device with the platinum bottom electrode, filamentary based resistive switching with good data retention was observed up to 125 °C. For the Al/Nb2O5/Al device, an area dependent pure electronic based resistive switching was observed. Electron trapping at the bottom electrode interface is responsible for the observed analog switching behavior which makes an Al/Nb2O5/Al device suitable for neuromorphic applications.

  3. Effects of Al(III) and Nano-Al13 Species on Malate Dehydrogenase Activity

    PubMed Central

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al13 concentration increase. Our study also found that the effects of Al(III) and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules. PMID:22163924

  4. Short-period superlattices of AlN/Al0.08Ga0.92N grown on AlN substrates S. A. Nikishin,a)

    E-print Network

    Holtz, Mark

    energy electron diffraction (RHEED). The Al-face AlN substrates11 were nominally (0001) ori- ented and Nano Tech Center, Texas Tech University, Lubbock, Texas 79409-3102 M. Holtz Nano Tech Center-source molecular-beam epitaxy with ammonia on Al face of AlN (0001) substrates. A significant reduction

  5. Two-Phase (TiAl+TiCrAl) Coating Alloys for Titanium Aluminides

    NASA Technical Reports Server (NTRS)

    Brady, Michael P. (Inventor); Smialek, James L. (Inventor); Brindley, William J. (Inventor)

    1998-01-01

    A coating for protecting titanium aluminide alloys, including the TiAl gamma + Ti3Al (alpha(sub 2)) class, from oxidative attack and interstitial embrittlement at temperatures up to at least 1000 C. is disclosed. This protective coating consists essentially of titanium, aluminum. and chromium in the following approximate atomic ratio: Ti(41.5-34.5)Al(49-53)Cr(9.5-12.5)

  6. Surface Superstructures of Ordered Layers of Al2O3 on Ni3Al(001)

    Microsoft Academic Search

    Oleg Kurnosikov; Cees F. J. Flipse; Henk J. M. Swagten; Bert Koopmans; Wim J. M. de Jonge

    2006-01-01

    Atomically ordered Al2O3 obtained by thermal oxidation of the Ni3Al(001) surface was studied using scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). LEED analysis has shown that oxidation at 800 and 1100 K forms two different structural phases of Al2O3. Detailed STM studies of both phases also reveal remarkable differences in surface pattern structure and arrangement of the domains.

  7. Comparing characteristics of serrations in Al–Li and Al–Mg alloys

    Microsoft Academic Search

    Baohui Tian

    2003-01-01

    Characteristics of serrations in the flow stress–strain curves of Al–1Mg and Al–2Li alloys, obtained from tensile tests, are analyzed and compared. The analysis includes stress drop, drop time and reload time at various ageing durations of the alloys. Changes in distributions of the stress drops and the drop time with changing the ageing duration differ markedly in Al–2Li from those

  8. Molecular beam epitaxial regrowth on insitu plasma-etched AlAs\\/AlGaAs heterostructures

    Microsoft Academic Search

    Kent D. Choquette; M. Hong; R. S. Freund; S. N. G. Chu; J. P. Mannaerts; R. C. Wetzel; R. E. Leibenguth

    1992-01-01

    Epitaxial regrowth by solid-source molecular beam epitaxy (MBE) on dry etched heterostructures possessing exposed AlAs surfaces is accomplished for the first time using a vacuum integrated processing. Samples composed of multilayers of AlAs and AlGaAs are patterned with a SiO2 mask and are anisotropically etched using a low damage electron cyclotron resonance (ECR) SiCl4 plasma process. Etched samples are transferred

  9. NMR measurements and hybridization behavior in Al_3Zr, Al_3Hf, and related intermetallics

    Microsoft Academic Search

    Chin Shan Lue Ross Jr.

    2001-01-01

    We report ^27Al NMR measurements on aluminum-rich intermetallics, including the DO_23-structured alloys Al_3Zr and Al_3Hf, and related close-packed structures. We determined the quadrupole splittings and Knight shifts, giving site-dependent structural information. The Knight shift tensors indicate strong directional bonding in the DO_23 alloys, despite the modified close-pack structures. This is especially true for sites I and III. The non-zero asymmetry

  10. Structure of 26Al studied by one - nucleon transfer reaction 27Al(d,t)

    NASA Astrophysics Data System (ADS)

    Srivastava, Vishal; Bhattacharya, C.; Rana, T. K.; Manna, S.; Kundu, S.; Bhattacharya, S.; Banerjee, K.; Roy, P.; Pandey, R.; Mukherjee, G.; Ghosh, T. K.; Meena, J. K.; Roy, T.; Chaudhuri, A.; Sinha, M.; Saha, A.; Dey, A.; Asgar, Md. A.; Roy, Subinit; Shaikh, Md. M.

    2015-01-01

    The excited states of 26Al have been produced and studied using 27Al(d,t) reaction with 25 MeV deuteron as projectile. Optical model potential parameters were extracted from the measured elastic scattering angular distribution. Zero range distorted wave Born approximation analysis for the ground and 0.223 MeV states of 26Al have been done. The spectroscopic factors calculated for these states are found to be in good agreement with the previously reported values.

  11. Remarks on Peinado et al.'s Analysis of J3Gen.

    PubMed

    Garcia-Alfaro, Joaquin; Herrera-Joancomartí, Jordi; Melià-Seguí, Joan

    2015-01-01

    Peinado et al. analyzed the security of the J3Gen pseudorandom number generator proposed by Melià-Seguí et al., and claimed weaknesses regarding its security properties. They also presented a deterministic attack based on the decimation of the J3Gen output sequences. We show that the assumptions made by Peinado et al. are not correct and that the proposed deterministic attack against J3Gen does not hold in practice. PMID:25781510

  12. Thermodynamic properties of alloys of the Al-Co and Al-Co-Sc systems

    NASA Astrophysics Data System (ADS)

    Shevchenko, M. A.; Berezutskii, V. V.; Ivanov, M. I.; Kudin, V. G.; Sudavtsova, V. S.

    2014-05-01

    Enthalpies of mixing for melts of the binary Al-Co system at 1870 K in the range 0 < x Co < 0.25, and at 1620 K, 0 < x Co < 0.12, are investigated by means of isoperibolic calorimetry. Enthalpies of mixing for melts of the ternary Al-Co-Sc system are investigated at 1870 K for sections Al0.75(1 - x)Co0.25(1 - x)Sc x , 0 < x < 0.024, and Al0.88(1 - x)Co0.12(1 - x)Sc x , 0 < x < 0.044. Using the literature data on the enthalpies of mixing for liquid and solid alloys, the activities of melt components, and the phase diagram of the Al-Co system, the thermodynamic properties of liquid and solid alloys of the Al-Co system over a wide range of temperatures and compositions are calculated using a software package of our own design, based on the model of ideal associated solutions (IAS). The enthalpies of mixing and the liquidus surface of the phase diagram of the ternary Al-Co-Sc system over the interval of concentrations are estimated by modeling with data on binary boundary subsystems. All of the components of both the binary Al-Co and ternary Al-Co-Sc systems tend to interact with one another quite strongly: ? H min(Al-Co) = -32.5 kJ/mol at x Co = 0.44; ? H min(Al-Co-Sc) = -46 kJ/mol for Al0.4Co0.3Sc0.3 (estimated).

  13. The lowest ionization potentials of Al2

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.

    1988-01-01

    Potential curves for the lowest two electronic states (X 2 sigma g + and A 2 pi u) of Al2(+) were computed using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2(+) X 2 sigma g +) of the Al2 X 3 pi u ground state is calculated to occur around 6.1 eV, in excellent agreement with the experimental range of 6.0 to 6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2(+) A 2 pi u) occurs near 6.4 eV, also within the experimental range. The adiabatic IP of 5.90 eV is in good agreement with the value of 5.8 to 6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision induced dissociation processes of Al3(+). The computed IP values are somewhat larger than those deduced from branching ratios in cluster fragmentation experiments by Jarrold and co-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3 sigma g -, but the separation between the two lowest states of Al2 is so small that it is likely that both are populated in the experiments, so that this does not provide unambiguous support for the recent theoretical assignment of the ground state as 3 pi u.

  14. 77 FR 40492 - Revocation of Class D Airspace; Andalusia, AL; and Amendment of Class E Airspace; Fort Rucker, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-10

    ...also updates the geographic coordinates of the above airport; Cairns AAF, Ft. Rucker, AL; and Florala Municipal, AL, to be...ASO AL E5 Fort Rucker, AL [Amended] Fort Rucker, Cairns AAF, AL (Lat. 31[deg]16'33'' N., long....

  15. Long range order and vacancy properties in Al-rich Fe{sub 3}Al and Fe{sub 3}Al(Cr) alloys

    SciTech Connect

    Kim, S.M. [AECL, Chalk River, Ontario (Canada). Chalk River Labs.] [AECL, Chalk River, Ontario (Canada). Chalk River Labs.; Morris, D.G. [Univ. of Neuchatel (Switzerland). Inst. of Structural Metallurgy] [Univ. of Neuchatel (Switzerland). Inst. of Structural Metallurgy

    1998-05-01

    Neutron powder diffraction measurements have been carried out in situ from room temperature to about 100 C in Fe28Al (28 at.% Al), Fe32.5Al (32.5 at.% Al) and Fe28Al15Cr (28 at.% Al, 5 at.% Cr) alloys. X-ray diffraction and TEM studies provided supporting information. The data were analyzed to obtain information about the temperature dependence of the DO{sub 3} and B2 long range order parameters, the location of the Cr atoms and their effect on the ordering energies, and on the vacancy formation and migration properties in Fe28Al and Fe32.5Al alloys. The location of the ternary alloying addition in DO{sub 3} and B2 ordered Al-rich Fe{sub 3}Al is shown to be consistent with considerations of interatomic bond energies.

  16. Possible Involvement of Al-Induced Electrical Signals in Al Tolerance in Wheat.

    PubMed Central

    Papernik, L. A.; Kochian, L. V.

    1997-01-01

    The relationship between Al-induced depolarization of root-cell transmembrane electrical potentials (Em) and Al tolerance in wheat (Triticum aestivum L.) was investigated. Al exposure induced depolarizations of Em in the Al-tolerant wheat cultivars Atlas and ET3, but not in the Al-sensitive wheat cultivars Scout and ES3. The depolarizations of Em occured in root cap cells and as far back as 10 mm from the root tip. The depolarization was specific to Al3+; no depolarization was observed when roots were exposed to the rhizotoxic trivalent cation La3+. The Al-induced depolarization occurred in the presence of anion-channel antagonists that blocked the release of malate, indicating that the depolarization is not due to the electrogenic efflux of malate2-. K+-induced depolarizations in the root cap were of the same magnitude as Al-induced depolarizations, but did not trigger malate release, indicating that Al-induced depolarization of root cap cell membrane potentials is probably linked to, but is not sufficient to trigger, malate release. PMID:12223834

  17. High temperature deformation of NiAl and CoAl

    NASA Technical Reports Server (NTRS)

    Nix, W. D.

    1982-01-01

    The high temperature mechanical properties of the aluminides are reviewed with respect to their potential as high temperature structural materials. It is shown that NiAl and CoAl are substantially stronger than the pure metals Ni and Co at high temperatures and approach the strength of some superalloys, particularly when those superalloys are tested in "weak" directions. The factors that limit and control the high temperature strengths of NiAl and CoAl are examined to provide a basis for the development of intermetallic alloys of this type.

  18. Achieving conductive high Al-content AlGaN alloys for deep UV photonics

    NASA Astrophysics Data System (ADS)

    Fan, Z. Y.; Lin, J. Y.; Jiang, H. X.

    2007-02-01

    Recent progresses in epitaxial growth and fundamental studies on electrical and optical properties of high Al-content AlGaN alloys with Si, Mg, and Zn doping are presented. For Si doped Al xGa1- xN, the Si activation energy was determined for x = 0 up to 1, and the resistivity of n-Al xGa1- xN was found to increases by one order of magnitude when Al content is increased by ~ 8%. From photoluminescence (PL) studies, three groups of deep impurity transitions were observed, related with deep level acceptors involving cation vacancy and its complexes: (VIII) 3-, (VIII-complex)2, and (VIII-complex) 1-, which are electron traps and compensating centers. By optimizing the growth processes to reduce the densities of cation vacancy and its complexes, the n-type conductivity of Al xGa1- xN was significantly improved. A record low room temperature n-type resistivity of 0.0075 ?•cm has been obtained for Al 0.7Ga 0.3N, and n-type conduction in pure AlN has also been achieved. We also review the electrical and optical measurement results of Mgdoped AlGaN and AlN. It was found that the overall material quality and conductivity of Mg-doped AlN are strongly correlated with the PL emission intensity of the nitrogen vacancy (V N 3+) related transition. Improved conductivity was obtained by suppressing the V N 3+ related emission line, which was attributed to the reduced hole compensation by V N 3+. With the identification of the emission peaks associated with V N 3+ hole compensating centers, the p-type conductivity of high Al-content AlGaN alloys was improved by monitoring and suppressing the intensity of the V N 3+ related emission lines. P-type conduction in Al xGa1- xN (x > 0.7) was confirmed at elevated temperatures (> 700 K). The possibility of using Zn as an alternative p-type dopant was also studied. It was found that contrary to the calculation, the energy level of Zn acceptor in AlN was about 0.74 eV, which is 0.23 eV deeper than Mg level in AlN.

  19. Photoemission from Al Alloys during Tensile Deformation

    NASA Astrophysics Data System (ADS)

    Cai, Mingdong; Langford, Stephen; Levine, Lyle; Dickinson, Thomas

    2004-03-01

    We report simultaneous measurements of strain and photoelectron emission intensity from high purity Al (1350), Al-Mg (5052), Al-Mn (3003), Al-Cu (2024) and Al-Mg-Si (6061) alloys under uniaxial tension due to pulsed excimer laser radiation (248-nm). The photoemission signals are sensitive to deformation-induced changes in surface morphology, including the formation of slip lines and slip bands. In the early stages of deformation (strain Â¡Ü 0.03), the photoemission intensity increases gradually in a nonlinear fashion. Depending on sample composition and heat treatment, the photoemission intensity subsequently grows linearly until the accumulated strain reaches about 0.20. Finally, the photoemission intensity increases parabolically until failure. The onset of strain localization corresponds to the transition from linear to parabolic growth. A constitutional model incorporating microstructure evolution and work-hardening during tensile deformation is proposed to qualitatively interpret the growth of the photoemission signals as a function of strain. The photoemission signals from the tested alloys are interpreted in terms of the effect of surface treatment, work function, microstructure, and composition on the development of dislocation structures during deformation.

  20. Indigenous Students' Attitudes towards Learning English through a Virtual Program: A Study in a Colombian Public University (Actitudes de estudiantes indígenas frente al aprendizaje de inglés a través de un programa virtual: un estudio en una universidad pública colombiana)

    ERIC Educational Resources Information Center

    Cuasialpud Canchala, Ruth Elena

    2010-01-01

    This article reports an exploratory study carried out at a public university in Bogotá, Colombia, with two indigenous students who took a level I virtual English-course during the second term of 2008 and the first term of 2009. The aim was to analyse their attitudes towards the learning of English through the virtual modality. Interviews,…

  1. Mg-doped Al-rich AlGaN alloys for deep UV emitters

    NASA Astrophysics Data System (ADS)

    Nakarmi, Mim L.; Kim, Kyoung Hoon; Zhu, Kai; Lin, Jing Yu; Jiang, Hong Xing

    2004-10-01

    Mg doped Al-rich AlGaN epilayers with Al content as high as 0.7 is needed for obtaining deep UV LEDs with wavelengths shorter than 300 nm. This is one of the most crucial layers in deep UV LEDs and plays an important role for electron blocking and affects the hole injection into the active layer. Not only is this layer critical for the efficiency of deep UV LEDs, it could also introduce long wavelength emission components in UV LEDs. However, it is difficult to obtain high quality Mg doped Al-rich AlGaN epilayers and the resistivity of the grown films is usually extremely high. We report here on the growth, optical and electrical properties of Mg doped Al0.7Ga0.3N epilayers. Mg doped Al0.7Ga0.3N epilayers of high crystalline and optical qualities have been achieved after optimizing MOCVD growth conditions. Moreover, we have obtained a resistivity around 12,000 ? cm (near the theoretical limit with Mg doping) at room temperature and confirmed p-type conduction at elevated temperatures for optimized Mg-doped Al0.7Ga0.3N epilayers. The growth conditions of the optimized epilayer have been incorporated into deep UV LEDs with wavelength shorter than 300 nm. A significant enhancement in power output with a reduction in forward voltage, Vf, was obtained by employing this optimized Mg doped Al0.7Ga0.3N epilayer as an electron blocking layer. The long wavelength emission components in deep UV LEDs were also significantly suppressed. The fundamental limit for achieving p-type Al-rich AlGaN alloys is also discussed.

  2. ALS and Frontotemporal Dysfunction: A Review

    PubMed Central

    Achi, Eugene Y.; Rudnicki, Stacy A.

    2012-01-01

    Though once believed to be a disease that was limited to the motor system, it is now apparent that amyotrophic lateral sclerosis (ALS) may be associated with cognitive changes in some patients. Changes are consistent with frontotemporal dysfunction, and may range from mild abnormalities only recognized with formal neuropsychological testing, to profound frontotemporal dementia (FTD). Executive function, behavior, and language are the most likely areas to be involved. Screening helpful in detecting abnormalities includes verbal or categorical fluency, behavioral inventories filled out by the caregiver, and evaluation for the presence of depression and pseudobulbar affect. Patients with cognitive dysfunction have shortened survival and may be less compliant with recommendations regarding use of feeding tubes and noninvasive ventilation. Evolving knowledge of genetic and pathological links between ALS and FTD has allowed us to better understand the overlapping spectrum of ALS and FTD. PMID:22919484

  3. The mechanical properties of FeAl

    SciTech Connect

    Baker, I. [Dartmouth Coll., Hanover, NH (United States); George, E.P. [Oak Ridge National Lab., TN (United States)

    1996-12-31

    Only in the last few years has progress been made in obtaining reproducible mechanical properties data for FeAl. Two sets of observations are the foundation of this progress. The first is that the large vacancy concentrations that exist in FeAl at high temperature are easily retained at low temperature and that these strongly affect the low-temperature mechanical properties. The second is that RT ductility is adversely affected by water vapor. Purpose of this paper is not to present a comprehensive overview of the mechanical properties of FeAl but rather to highlight our understanding of key phenomena and to show how an understanding of the factors which control the yield strength and fracture behavior has followed the discovery of the above two effects. 87 refs, 9 figs.

  4. [Al-Biruni--a universal scientist].

    PubMed

    Kujundzi?, E; Masi?, I

    1999-01-01

    Al-Biruni's was of Persian descent. He was born in Horesmiya and had studied mathematics, history and medicine. Acquiring knowledge from these sciences, he wrote an outstanding work on chronology of several nations and devoted it to Ziyarit ruler Kabus. He made a chronological overview of calendars from many nations, including Persians, Greeks, Egyptians, Jews, Melkitian and Nestorian Christians, Sabeyaans as well as the old Arabs. Data presented in the work, according to the later authors, were taken from very reliable sources. He was contemporary of Ibn-Sina, and thanks to their friendship, they have discussed very much miscellaneous topics. He belonged to the group of scholars, taken by Gaznevian Soultan Mahmud to a long journey to India. Afterwards Al-Biruni wrote and published detailed work "Description of India"--a work on cultural history of India. Due to excellent abilities of Al-Biruni as a philosopher and scholar, there are still significant and reliable notes about buddhistic philosophy, structure of castes and Brahmans' life style. In this Al-Biruni's masterpiece, there are many comparative analysis of Suffism and certain Indian philosophical methods. Al-Biruni's most important work is "Pharmacopoeia"--"Kitab al-saydala", which brilliantly describes all medicaments. This work has been published in many languages. He also wrote few works on astronomy and astrology. In those works he has explained some astrological events through scientific approach in a such peculiar way that nobody has ever explained before. He was also interested in sciences like geology, mineralology, geography, mathematics, psychology and many others. PMID:10386051

  5. Nb3Al Development for HEP Applications

    SciTech Connect

    Sumption, M.D.; Buta, F.; Collings, E.W. [Laboratories for Applied Superconductivity and Magnetism (LASM), MSE Dept, The Ohio State University, Columbus, OH 43210 (United States); Tomsic, M.; Phillips, J.; McFadden, K. [Hyper Tech Research Inc., Troy, OH 45373 (United States); Wu, X

    2004-06-28

    Recent developments in Nb3Al strand for HEP applications are presented and discussed. The present state of available precursor is detailed. Two routes have been shown to lead to successful construction of MF NbAl composite wires. An extrusion method has so far produced the highest filament counts and smallest filament diameters, but requires more processing steps. A direct restack and draw approach has also been demonstrated which minimizes the number of processing steps while still leading to a high performance conductor. This latter route also allows for a lower cost per billet, potentially allowing the exploration of more process parameters.

  6. An Alternative Perspective on von Winterfeldt et al.'s (1997) Test of Consequence Monotonicity

    ERIC Educational Resources Information Center

    Ho, Moon-Ho R.; Regenwetter, Michel; Niederee, Reinhard; Heyer, Dieter

    2005-01-01

    D. von Winterfeldt, N.-K. Chung, R. D. Luce, and Y. Cho (see record 1997-03378-008) provided several tests for consequence monotonicity of choice or judgment, using certainty equivalents of gambles. The authors reaxiomatized consequence monotonicity in a probabilistic framework and reanalyzed von Winterfeldt et al.'s main experiment via a…

  7. A unique description of steady state deformation of Al and Al-Mg alloys

    Microsoft Academic Search

    G. Bermig; A. Bartels; H. Mecking; Y. Estrin

    1997-01-01

    In this work, simple mathematical relations between the plastic strain rate, the flow stress and the temperature for steady state deformation of aluminium alloys are proposed. The expressions are based on the corresponding formula for pure Al considered as a reference material. A ‘master curve’ representing this relation for Al was obtained through a compilation of a large array of

  8. Thermal behavior of Al and Al3 at. % Ge thin films on Si wafers

    Microsoft Academic Search

    B. S. Lim; W. C. Pritchet; K. P. Rodbell; K. N. Tu

    1993-01-01

    The mechanical stresses of a pure Al film and a low-thermal-expansion Al-3 at. % Ge thin film on (100) Si wafers are measured and compared in the temperature range of room temperature to 400 °C by the vibrating membrane method. The results are discussed including the comparison with those obtained by the popular wafer bending method. It was found that

  9. ^27Al-NMR Study of the Spinel Compound CoAl2O4

    NASA Astrophysics Data System (ADS)

    Roy, Beas; Pandey, Abhishek; Johnston, David C.; Furukawa, Yuji

    2013-03-01

    CoAl2O4, a geometrically frustrated magnet, is believed to be located in the vicinity of a quantum melting point of the AFM ordered state. In CoAl2O4, magnetic frustration originates from Co^2+(S = 3/2) spins on the tetrahedral A-site via non-magnetic Al ions occupying the octahedral B-site. To study the magnetic properties of CoAl2O4 from a microscopic point of view, we have carried out ^27Al-NMR measurements using a well-characterized powder sample of CoAl2O4. The temperature dependence of the magnetic susceptibility ? shows a broad peak around 15 K and does not show any difference in zero-field-cooled and field-cooled measurements. ^27Al-NMR spectra at 9.3 MHz (H = 0.84 T) show seven peaks characterized by quadrupolar splitting with ?Q= 0.55 MHz at temperatures above 10 K. Below 10 K, the spectrum broadens suddenly. We also observe a peak of 1/T1 of ^27Al at 10 K. These NMR results clearly indicate magnetic ordering at 10 K, although ? does not exhibit any signature of long-range magnetic ordering.

  10. Electronic circuits having NiAl and Ni.sub.3 Al substrates

    DOEpatents

    Deevi, Seetharama C. (Midlothian, VA); Sikka, Vinod K. (Oak Ridge, TN)

    1999-01-01

    An electronic circuit component having improved mechanical properties and thermal conductivity comprises NiAl and/or Ni.sub.3 Al, upon which an alumina layer is formed prior to applying the conductive elements. Additional layers of copper-aluminum alloy or copper further improve mechanical strength and thermal conductivity.

  11. Structures of AlN/VN superlattices with different AlN layer thicknesses

    E-print Network

    Marks, Laurence D.

    , is characterized by high ionicity, short bond length, low compressibility, high thermal conductivity, and a wide B1-AlN, suggests that the phase transition is martensitic. II. EXPERIMENTAL PROCEDURES AlN/VN superlattices were grown on MgO(001) sub- strates in an ultrahigh vacuum dc-magnetron sputtering system that has

  12. Replication and Extension of Little et al.'s (2003) Forms and Functions of Aggression Measure

    ERIC Educational Resources Information Center

    Fite, Paula J.; Stauffacher, Kirstin; Ostrov, Jamie M.; Colder, Craig R.

    2008-01-01

    The goal of the current study was to replicate the confirmatory factor analysis of Little et al.'s (2003) aggression measure in an American sample of 69 children (mean age = 12.93 years; SD = 1.27). Although an exact replication of the original model could not be estimated given the small sample, a modified model representing a conceptual…

  13. Melting, Processing, and Properties of Disordered Fe-Al and Fe-Al-C Based Alloys

    NASA Astrophysics Data System (ADS)

    Satya Prasad, V. V.; Khaple, Shivkumar; Baligidad, R. G.

    2014-09-01

    This article presents a part of the research work conducted in our laboratory to develop lightweight steels based on Fe-Al alloys containing 7 wt.% and 9 wt.% aluminum for construction of advanced lightweight ground transportation systems, such as automotive vehicles and heavy-haul truck, and for civil engineering construction, such as bridges, tunnels, and buildings. The melting and casting of sound, porosity-free ingots of Fe-Al-based alloys was accomplished by a newly developed cost-effective technique. The technique consists of using a special flux cover and proprietary charging schedule during air induction melting. These alloys were also produced using a vacuum induction melting (VIM) process for comparison purposes. The effect of aluminum (7 wt.% and 9 wt.%) on melting, processing, and properties of disordered solid solution Fe-Al alloys has been studied in detail. Fe-7 wt.% Al alloy could be produced using air induction melting with a flux cover with the properties comparable to the alloy produced through the VIM route. This material could be further processed through hot and cold working to produce sheets and thin foils. The cold-rolled and annealed sheet exhibited excellent room-temperature ductility. The role of carbon in Fe-7 wt.% Al alloys has also been examined. The results indicate that Fe-Al and Fe-Al-C alloys containing about 7 wt.% Al are potential lightweight steels.

  14. University of AlAskA AnchorAge AlAskA Justice Forum

    E-print Network

    Pantaleone, Jim

    University of AlAskA AnchorAge AlAskA Justice Forum A PUblicAtion of the JUstice center Fall 2013 in Alaska and nationally (page 2). · An update on the work of the Alaska Prisoner Reentry Task Force (page 5 Collateral Consequences and Reentry in Alaska: An Update Deborah Periman "Our legal system has created

  15. University of AlAskA AnchorAge AlAskA Justice Forum

    E-print Network

    Pantaleone, Jim

    University of AlAskA AnchorAge AlAskA Justice Forum A PUblicAtion of the JUstice center Summer 2013 Vol. 30, No. 2 Please see Alcohol, page 13 Reducing Sales of Alcohol to Underage Persons in Alaska within a few hours) in the past month, more than one quarter of youth in public high schools in Alaska

  16. AlAskA Justice Forum University of AlAskA AnchorAge

    E-print Network

    Pantaleone, Jim

    AlAskA Justice Forum University of AlAskA AnchorAge A PUblicAtion of the JUstice center Fall 2008 to Alaska State Troopers Marny Rivera, André B. Rosay, Darryl S. Wood, Greg Postle, and Katherine Te violence is an undeniable urban and rural problem in Alaska and the nation. Detailed data on domestic

  17. Directional Solidification and Mechanical Properties of NiAl-NiAlTa Alloys

    NASA Technical Reports Server (NTRS)

    Johnson, D. R.; Chen, X. F.; Oliver, B. F.; Noebe, R. D.; Whittenberger, J. D.

    1995-01-01

    Directional solidification of eutectic alloys is a promising technique for producing in-situ composite materials exhibiting a balance of properties. Consequently, the microstructure, creep strength and fracture toughness of directionally solidified NiAl-NiAlTa alloys were investigated. Directional solidification was performed by containerless processing techniques to minimize alloy contamination. The eutectic composition was found to be NiAl-15.5 at% Ta and well-aligned microstructures were produced at this composition. A near-eutectic alloy of NiAl-14.5Ta was also investigated. Directional solidification of the near-eutectic composition resulted in microstructures consisting of NiAl dendrites surrounded by aligned eutectic regions. The off-eutectic alloy exhibited promising compressive creep strengths compared to other NiAl-based intermetallics, while preliminary testing indicated that the eutectic alloy was competitive with Ni-base single crystal superalloys. The room temperature toughness of these two-phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa.

  18. Nucleosynthesis of Al26 in massive stars: New Al27 states above ? and neutron emission thresholds

    NASA Astrophysics Data System (ADS)

    Benamara, S.; de Séréville, N.; Laird, A. M.; Hammache, F.; Stefan, I.; Roussel, P.; Ancelin, S.; Assié, M.; Coc, A.; Deloncle, I.; Fox, S. P.; Kiener, J.; Lefebvre, L.; Lefebvre-Schuhl, A.; Mavilla, G.; Morfouace, P.; Sánchez-Benítez, Á. M.; Perrot, L.; Sinha, M.; Tatischeff, V.; Vandebrouck, M.

    2014-06-01

    The 26Al radioisotope is of great importance for understanding the chemical and dynamical evolution of our galaxy. Among the possible stellar sources, massive stars are believed to be the main producer of this radioisotope. Understanding 26Al nucleosynthesis in massive stars requires estimates of the thermonuclear reaction rates of the Al26(n,p)26Mg, Al26(n,?)23Na, and Na23(?,p)26Mg reactions. These reaction rates depend on the spectroscopic properties of 27Al states above the neutron and alpha thresholds. In this context, the Al27(p,p')27Al* reaction was studied at 18 MeV using a high-resolution Enge Split-Pole spectrometer. States from the ground state up to excitation energies of ?14 MeV were populated. While up to the 23Na + ? threshold no additional states are observed, we report for the first time 30 new levels above the 23Na + ? threshold and more than 30 new states above the 26Al + n threshold for which excitation energies are determined with an uncertainty of 4-5 keV.

  19. Electronic structure and bonding at the Alterminated Al(111)/Al2O3(0001) interface: A first principles study

    E-print Network

    Adams, James B

    the mechanical properties of an interface, is the ideal work of adhesion, Ï ,[1] which is defined as the bondElectronic structure and bonding at the Al­terminated Al(111)/«­Al2O3(0001) interface: A first to determine the bonding character of the Al­terminated Al(111)/«­Al2O3(0001) interface. By using an optimized

  20. An impedance study of complex Al/Cu-Al2O3 electrode

    NASA Astrophysics Data System (ADS)

    Denisova, J.; Katkevics, J.; Erts, D.; Viksna, A.

    2011-06-01

    Electrochemical impedance spectroscopy (EIS) was used to investigate different Cu deposition regimes on Al surface obtained by internal electrolysis and to characterize properties of fabricated electrodes. EIS experimental data confirmed that Cu deposition by internal electrolysis is realized and the complex electrode system is obtained. The main difficulty in preparation of Al/Cu electrodes is to prevent aluminium oxidation before and during electrochemical deposition of Cu particles. In this work NaCl, CH3COONa, K2SO4, mono- and diammonium citrate electrolytes were examined to determine their suitability for impedance measurements. Al/Cu-Al2O3 electrode composition was approved by equivalent circuit analysis, optical and scanning electron microscope methods. The most optimal Cu deposition mode using internal electrolysis was determined. The obtained results are promising for future electrochemical fabrication of nanostructures directly on Al surfaces by internal electrolysis.

  1. Analysis of interface trap states in InAlN/AlN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Zhou, Yang; Lin, Zhaojun; Luan, Chongbiao; Zhao, Jingtao; Yang, Qihao; Yang, Ming; Wang, Yutang; Feng, Zhihong; Lv, Yuanjie

    2014-09-01

    Gate-source frequency-dependent capacitance and conductance measurements were performed on the In0.17Al0.83N/AlN/GaN heterostructure field-effect transistor with side-Ohmic contacts to study the characteristics of trap states at the interface between InAlN and GaN. The values of interface trap state density and time constant were determined to be (0.96-3.36) × 1013 cm-2 eV-1 and (0.29-1.61) ?s, respectively. We calculated the strain in the InAlN barrier layer under the gate and found that the InAlN barrier layer was compressively strained with the in-plane strain of 1.31%. This is a possible reason for such a high interface trap state density which is not as low as supposed in the lattice-matched heterostructures.

  2. Properties and structure of oxidized coatings deposited onto Al-Cu and Al-Mg alloys

    NASA Astrophysics Data System (ADS)

    Pogrebnyak, A. D.; Kylyshkanov, M. K.; Tyurin, Yu. N.; Kaverina, A. Sh.; Yakushchenko, I. V.; Borisenko, A. A.; Postol'ny, B. A.; Kulik, I. A.

    2012-06-01

    The results of new studies of creating protective oxide coatings based on Al2O3 (Si, Mn) and deposited onto aluminum alloys using electrolyte-plasma oxidation are presented. An analysis is performed by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), X-ray diffraction, Rutherford backscattering of 4He+ and protons, nanoindentation, scratching, friction coefficient measurements, and acoustic emission measurements. The results demonstrate that the deposited coatings have a high quality, hardness, and wear resistance and a low thermal diffusivity. Apart from Al2O3, the coatings are found to have Si, Mn, C, and Ca. The stoichiometry of the coatings is determined. The density and hardness of the coatings are close to those of ?-Al2O3 in the coating on an Al-Cu (D-16) substrate, and these values of the coating on an Al-Mg (S006) are lower by a factor of 1.5.

  3. 1300 K compressive properties of a reaction milled NiAl-AlN composites

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. Daniel; Arzt, Eduard; Luton, Michael J.

    1990-01-01

    When B2 crystal-structure nickel aluminide is subjected to high-intensity mechanical ball milling in a liquid nitrogen bath, or 'cryomilling', an NiAl composite is obtained which contains about 10 vol pct AlN particles. This composition arises from the incorporation of N during cryomilling; during subsequent thermomechanical processing, the N reacts with Al. While compressive testing of extruded or isostatically pressed specimens at 1300 K indicated that strength at relatively fast strain rates is slightly dependent on consolidation method, slower strain rates indicate no clear dependency on densification technique: four different consolidation methods were found to yield similar creep strengths. The creep properties of NiAl-AlN are similar to those of the single-crystal Ni-base superalloy NASAIR 100.

  4. Formation of gamma(sup prime)-Ni3Al via the Peritectoid Reaction: gamma + beta (+ Al2O3)=gamma(sup prime)(+ Al2O3)

    NASA Technical Reports Server (NTRS)

    Copeland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8-32 at.%Al and temperature range T=1400-1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma(sup prime)-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3)=gamma + Beta(+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%al (at an unknown oxygen content). The {gamma + Beta (+Al2O3} phase field is stable over the temperature range 1633-1640 K, and gamma(sup prime)-Ni3Al forms via the peritectoid, gamma + Beta (+ Al2O3)=gamma(sup prime) (+ Al2O3), at 1633 +/- 1 K. This behavior is consistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(sup prime)-Ni2Al phase field.

  5. Formation of gamma'-Ni3Al via the Peritectoid Reaction: gamma plus beta (+Al2O3) equals gamma'(+Al2O3)

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2008-01-01

    The activities of Al and Ni were measured using multi-cell Knudsen effusion-cell mass spectrometry (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K in the Ni-Al-O system. These measurements establish that equilibrium solidification of gamma'-Ni3Al-containing alloys occurs by the eutectic reaction, L (+ Al2O3) = gamma + beta (+ Al2O3), at 1640 plus or minus 1 K and a liquid composition of 24.8 plus or minus 0.2 at.%Al (at an unknown oxygen content). The {gamma + beta + Al2O3} phase field is stable over the temperature range 1633 - 1640 K, and gamma'-Ni3Al forms via the peritectiod, gamma + beta (+ Al2O3) = gamma'(+ Al2O3), at 1633 plus or minus 1 K. This behavior is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma'-Ni3Al phase field.

  6. Influence of reaction with XeF2 on surface adhesion of Al and Al2O3 surfaces

    Microsoft Academic Search

    Tianfu Zhang; Jeong Y. Park; Wenyu Huang; Gabor A. Somorjai

    2008-01-01

    The change in surface adhesion after fluorination of Al and Al2O3 surfaces using XeF2 was investigated with atomic force microscopy. The chemical interaction between XeF2 and Al and Al2O3 surfaces was studied by in situ x-ray photoelectron spectroscopy. Fresh Al and Al2O3 surfaces were obtained by etching top silicon layers of Si?Al and Si?Al2O3 with XeF2. The surface adhesion and

  7. Influence of reaction with XeF2 on surface adhesion of Al and Al2O3 surfaces

    Microsoft Academic Search

    Tianfu Zhang; Jeong Y. Park; Wenyu Huang; Gabor A. Somorjai

    2008-01-01

    The change in surface adhesion after fluorination of Al and Al2O3 surfaces using XeF2 was investigated with atomic force microscopy. The chemical interaction between XeF2 and Al and Al2O3 surfaces was studied by in situ x-ray photoelectron spectroscopy. Fresh Al and Al2O3 surfaces were obtained by etching top silicon layers of Si\\/Al and Si\\/Al2O3 with XeF2. The surface adhesion and

  8. Wear characteristics of Al-AlN composites produced in-situ by nitrogenation

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Jena, S. K.; Patnaik, S. C.; Swain, P. K.; Majhi, J.

    2015-02-01

    In the present scenario most of the parts used in automobile and aerospace industries are made of composites. Aluminium metal has a very high strength to weight ratio. Al-AlN metal matrix composites have excellent mechanical properties like good wear resistance, high hardness and high strength to weight ratio which are obtained from low density of aluminium and high hardness and wear resistance of AlN. Therefore, use of Al-AlN MMC leads to advantages in automobile industries as it reduces fuel consumption and gives better structural strength. The composites can be produced ex-situ by introducing AlN as reinforcement into the metal matrix and in- situ by nitrogenation process. In the present process Al-AlN composites were fabricated by treating molten aluminium with a mixture of CaO and NH4Cl and held at temperature range at 750-930°C and then cast into a metal mould. Addition of CaO to NH4Cl is found to have a more pronounced effect as a nitrogenation agent in comparison with NH4Cl in the molten aluminium in the temperature range of 700- 1000°C. Castings of aluminium and Al-AlN composites were prepared by mixing different ratios of aluminium and NH4Cl, at different casting temperatures and holding time. Wear resistance and hardness of the samples were determined, and microstructure studies were carried out. The composite formed using higher amount of NH4Cl had higher hardness and wear resistance.

  9. AL ASK A SALMON alaska Salmon

    E-print Network

    189 AL ASK A SALMON UNIT 13 alaska Salmon INTRODUCTION Pacific salmon have played an important and pivotal role in the history of Alaska. Salmon, along with mining, timber, and furs, were the keystone now, the abundant salmon resources of this region continue to shape much of the con- temporary lives

  10. U-ALS: A Ubiquitous Learning Environment

    ERIC Educational Resources Information Center

    Piovesan, Sandra Dutra; Passerino, Liliana Maria; Medina, Roseclea Duarte

    2012-01-01

    The diffusion of the use of the learning virtual environments presents a great potential for the development of an application which meet the necessities in the education area. In view of the importance of a more dynamic application and that can adapt itself continuously to the students' necessities, the "U-ALS" (Ubiquitous Adapted Learning…

  11. Microbial Bioreactor Development in the ALS NSCORT

    Microsoft Academic Search

    Cary Mitchell; Dawn Whitaker; M. Katherine Banks; Albert J. Heber; Ronald F. Turco; Loring F. Nies; James E. Alleman; Sybil E. Sharvelle; Congna Li; Megan Heller

    2008-01-01

    The NASA Specialized Center of Research and Training in Advanced Life Support (the ALS NSCORT), a partnership of Alabama A & M, Howard, and Purdue Universities, was established by NASA in 2002 to develop technologies that will reduce the Equivalent System Mass (ESM) of regenerative processes within future space life-support systems. A key focus area of NSCORT research has been

  12. Bierman {ital et al.}Reply:

    SciTech Connect

    Bierman, J.D.; Chan, P.; Liang, J.F.; Kelly, M.P.; Sonzogni, A.A.; Vandenbosch, R. [Nuclear Physics Laboratory University of Washington Seattle, Washington 98195 (United States)] [Nuclear Physics Laboratory University of Washington Seattle, Washington 98195 (United States)

    1997-05-01

    reply to the Comment by C.H.Dasso et al., Phys. Rev. Lett. 78,XXX(1997). A Reply to the Comment by C.H. Dasso and J. Fern{acute a}ndez-Niello. {copyright} {ital 1997} {ital The American Physical Society}

  13. (12) United States Patent Grier et al.

    E-print Network

    Grier, David

    (12) United States Patent Grier et al. US008502132B2 US 8,502,132 B2 Aug. 6, 2013 (10) Patent N0.: (45) Date of Patent: (54) (75) (73) (*) (21) (22) (65) (62) (60) (51) (52) MANIPULATION OF OBJECTS) Assignee: New York University, NeW York, NY (Us) Notice: Subject to any disclaimer, the term ofthis patent

  14. (12) United States Patent Vertes et al.

    E-print Network

    Vertes, Akos

    (12) United States Patent Vertes et al. (54) LASERABLATION ELECTROSPRAY IONIZATION (LAESI) ( *) Notice: Subject to any disclaimer, the term ofthis patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days. lbis patent is subject to a terminal dis- claimer. (21) Appl. No.: 131271,435 Oct. 12, 2011

  15. (12) United States Patent Geohegan et al.

    E-print Network

    Geohegan, David B.

    (12) United States Patent Geohegan et al. US008540542B2 US 8,540,542 B2 Sep. 24, 2013 (10) Patent N0.: (45) Date of Patent: (54) TRANSPARENT CONDUCTIVE NANO-COMPOSITES (75) Inventors: David Bruce Research Foundation, Knoxville, TN (US) Notice: Subject to any disclaimer, the term ofthis patent

  16. COMUNICATO STAMPA Tiroide, visite gratuite al Ruggi

    E-print Network

    Costagliola, Gennaro

    effettuando visite gratuite con ecografia della tiroide presso il Day Service di Patologia Tiroidea, diretto:00 presso il Day Service di Patologia Tiroidea al 4° piano del corpo C-D dell'AOU S. Giovanni di Dio e Ruggi

  17. Luminescence in Li? Al ? (PO?)? :Eu(2+).

    PubMed

    Shinde, K N; Park, K

    2013-01-01

    A series of efficient Li? Al ? (PO?)? :Eu(2+) novel phosphors were synthesized by the facile combustion method. The effects of dopant on the luminescence behavior of Li? Al ? (PO?)? phosphor were also investigated. The phosphors were characterized by X-ray diffraction, field emission scanning electron microscope and photoluminescence techniques. The result shows that all samples can be excited efficiently by near-ultraviolet excitation under 310?nm. The emission was observed for Li? Al ? (PO?)? :Eu(2+) phosphor at 425?nm, which corresponded to the d ? f transition. The concentration quenching of Eu(2+) was observed in Li? Al ? (PO?)? :Eu(2+) when the Eu concentration was at 0.5?mol%. The prepared powders exhibited intense blue emission at the 425?nm owing to the Eu(2+) ion by Hg-free excitation at 310?nm (i.e., solid-state lighting excitation). Consequently, the availability of such a phosphor will significantly help in the development of blue-emitting solid-state lighting applications. PMID:23019178

  18. AgriculturAl 2013 Annual Report

    E-print Network

    Goodman, Robert M.

    Dean of Agriculture and Natural Resources Rutgers, The State University of New Jersey ExecutiveNew Jersey AgriculturAl experimeNt stAtioN 2013 Annual Report #12;To enhance the vitality, health, sustainability, and overall quality of life in New Jersey by developing and delivering practical, effective

  19. Correction to Rothermund et al. (2005)

    ERIC Educational Resources Information Center

    Rothermund, Klaus; Wentura, Dirk; De Houwer, Jan

    2005-01-01

    This article reports an error in the article "Retrieval of Incidental Stimulus-Response Associations as a Source of Negative Priming" by Rothermund et al. ("Journal of Experimental Psychology: Learning, Memory, and Cognition," Vol 31(3) May 2005, 482-495). Table 1 (p. 484) was incorrectly typeset. The correct layout is provided. (The following…

  20. (12) United States Patent Colace et al.

    E-print Network

    Shamos, Michael I.

    (12) United States Patent Colace et al. (54) (75) (73) SYSTEM AND METHOD ALLOWING ADVERTISERS, Toluca Lake, CA (US); Scott W. Snell, Hollywood, CA (US); Jeremy Daw, Alta Lorna, CA (US); Dominic Dough-Ming Cheung, South Pasadena, CA (US); Benjamin James Watkins, Torrance, CA (US); Thomas A. Soulanille

  1. 4, 309333, 2008 T. Arsouze et al.

    E-print Network

    Paris-Sud XI, Université de

    CPD 4, 309­333, 2008 Neodymium modelling T. Arsouze et al. Title Page Abstract Introduction of the Atlantic thermohaline circulation on neodymium isotopic composition at the Last Glacial Maximum Publications on behalf of the European Geosciences Union. 309 #12;CPD 4, 309­333, 2008 Neodymium modelling T

  2. Das Faktorisierungsrepr asentationsproblem als Basis kryptographischer Protokolle

    E-print Network

    Wolfgang Goethe-Universit at in Frankfurt am Main | von Roger Fischlin aus O#11;enbach am Main | Frankfurt am Main 2002 D F 1 #12; ii Vom Fachbereich Mathematik der Johann Wolfgang Goethe-Universit at als Mitarbeit von 1998 bis 2001 in der Gruppe von Prof. Dr.Schnorr am Fachbereich Ma- thematik der J.W.Goethe

  3. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, Jr., Karl A. (Ames, IA); Takeya, Hiroyuki (Ibaraki, JP)

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy.sub.1-x Er.sub.x)Al.sub.2 for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant.

  4. (12) United States Patent Vertes et al.

    E-print Network

    Vertes, Akos

    ) PCTFiled: Jan. 26, 2006 (86) PCTNo.: PCT/US2006/002483 § 371 (c)(1), (2), (4) Date: Jul. 20, 2007 (87) PCT Pub. No.: W02006/081240 PCT Pub. Date: Aug. 3, 2006 (65) Prior Publication Data US 2008/0149822 Al lun

  5. The Rail Gun Muad Al Khaldi

    E-print Network

    Masoudi, Husain M.

    The Rail Gun Muad Al Khaldi Department of Electrical Engineering King Fahd University of Petroleum and Minerals Abstract- The rail gun is one of promising ways of launching projectiles. Recently, many. In this project, I am going to investigate the construction of electromagnetic rail guns, the way the function

  6. (12) United States Patent Bauer et al.

    E-print Network

    Shamos, Michael I.

    Intuit's Quicken InsureMarket Offering Online Auto Policies in 6 States, Dec. 1998, Business Wire(12) United States Patent Bauer et al. (54) APPARATUS FOR INTERNET ON-LINE INSURANCE POLICY SERVICE * 912000 OTHER PUBLICATIONS Pasher, Auto Web site takes off, Mar. 1998, National Underwriter (Propert

  7. (12) United States Patent Black et al.

    E-print Network

    Shamos, Michael I.

    Alamos, New Mexico. After one test explos:ion, two atomic .bombs: were dropped on the Japanese cities of Hiroshima (6 Aug 1945) and Nagasaki (9 _:Aug 1945); the bomb dropped on - .Hiroshima was as. powerful as metric tons of TNT, that on equivalent to 22.000 metrie tOI"ll The USSR first detbnated al'l atomic 1949

  8. Eigennutz als Triebfeder des Wohlstands: Die \\

    Microsoft Academic Search

    Roland Kirstein; Dieter Schmidtchen

    2002-01-01

    Die empirische Prüfung theoretischer Forschungsergebnisse wirft in der Ökonomie - wie bei jeder Sozialwissenschaft - Probleme auf. Anders als in den Naturwissenschaften können volkswirtschaftliche Problemstellungen kaum in Labors nachgestellt werden. Seit einigen Jahren nutzen Ökonomen allerdings die Erfahrungen der Psychologie mit stilisierten Experimenten, um zumindest ihre grundlegenden Verhaltenshypothesen testen zu können. Dieser Beitrag stellt ein einfaches Hörsaal-Experiment vor, das Adam

  9. Clinical trials in ALS: an overview.

    PubMed

    Turner, M R; Parton, M J; Leigh, P N

    2001-06-01

    Clinical trials in amyotrophic lateral sclerosis (ALS) have been conducted for over half a century now and have incorporated a wide variety of drugs. Most of these trials have had negative results and a cure remains elusive. The explosion in our understanding of molecular biology and parallel developments in clinical epidemiology have opened up a vast number of novel therapeutic strategies. However, advances in statistical analysis, computing, and global communications have also put greater pressure on scientific investigators to improve the design and implementation of clinical trials so that they permit rigorous testing of hypotheses within a solid ethical framework. This article documents the first published trial for all drugs tried clinically in the treatment of ALS, focusing in more detail on the large, multicenter trials of recent years, namely those involving riluzole, ciliary neurotrophic factor, insulin-like growth factor-I, brain-derived neurotrophic factor, and SR57746A. The problems in the design of trials in ALS are discussed, including the selection of end points and surrogate markers of disease progression, and the major parameters in ALS assessment are reviewed. PMID:11442325

  10. (12) United States Patent Vertes et al.

    E-print Network

    Vertes, Akos

    (12) United States Patent Vertes et al. (54) NANOPHOTONIC PRODUCTION, MODULATION AND SWITCHING a quasi-periodic antenna array with ion yields that show pro- found dependence on the plane oflaser light polarization and the angle of incidence. By providing photonic ion sources, this enables enhanced control

  11. Schler et al 2001 Mycol Arbuscular mycorrhiza

    E-print Network

    California at Berkeley, University of

    vulgaris colonized by arbuscular mycorrhizal fungi vesicle arbuscules (c) D. Redecker 10µm #12;Auxilary. Redecker, K. Wex10µm #12;SEM of arbuscles From Mycorrhizal Symbiosis #12;Devonian Fossil Modern Glomales Remy, Taylor et al. 1994 #12;From Gallaud 1905Arum type Paris type #12;AM Hyphae From Mycorrhizal

  12. Joint SSRTNet/ALS-MES Workshop report

    SciTech Connect

    Shuh, David; Van Hove, Michel

    2001-11-30

    This joint workshop brought together experimentalists and theorists interested in synchrotron radiation and highlighted subjects relevant to molecular environmental science (MES). The strong mutual interest between the participants resulted in joint sessions on the first day, followed by more specialized parallel sessions on the second day. Held in conjunction with the Advanced Light Source (ALS) Users' Association Annual Meeting at the Lawrence Berkeley National Laboratory (Berkeley Lab), the Synchrotron Radiation Research Theory Network (SRRTNet) workshop was co-organized by Michel Van Hove (Berkeley Lab and University of California, Davis) and Andrew Canning (Berkeley Lab), while David Shuh (Berkeley Lab) organized the ALS-MES workshop. SRRTNet is a global network that promotes the interaction of theory and experiment (http://www.cse.clrc.ac.uk/Activity/SRRTnet). The ALS-MES project is constructing Beamline 11.0.2.1-2, a new soft x-ray beamline for MES investigations at photon energies from 75 eV to 2 keV, to provide photons for wet spectroscopy end stations and an upgraded scanning transmission x-ray microscope (STXM). The ALS-MES beamline and end stations will be available for users in the late fall of 2002.

  13. Ternary Dy-Er-Al magnetic refrigerants

    DOEpatents

    Gschneidner, K.A. Jr.; Takeya, Hiroyuki

    1995-07-25

    A ternary magnetic refrigerant material comprising (Dy{sub 1{minus}x}Er{sub x})Al{sub 2} for a magnetic refrigerator using the Joule-Brayton thermodynamic cycle spanning a temperature range from about 60K to about 10K, which can be adjusted by changing the Dy to Er ratio of the refrigerant. 29 figs.

  14. Kinematics of Disease Progression in Bulbar ALS

    ERIC Educational Resources Information Center

    Yunusova, Yana; Green, Jordan R.; Lindstrom, Mary J.; Ball, Laura J.; Pattee, Gary L.; Zinman, Lorne

    2010-01-01

    The goal of this study was to investigate the deterioration of lip and jaw movements during speech longitudinally in three individuals diagnosed with bulbar amyotrophic lateral sclerosis (ALS). The study was motivated by the need to understand the relationship between physiologic changes in speech movements and clinical measures of speech…

  15. Qiu & al. Basal angiosperm phylogeny55 (4) November 2006: 837856 INTRODUCTION

    E-print Network

    , 1999; P. Soltis & al., 1999; Barkman & al., 2000; Graham & Olmstead, 2000; Savolainen & al., 2000., 1999; Barkman & al., 2000; Graham & Olmstead, 2000; D. Soltis & al., 2000; Zanis & al., 2002; Borsch

  16. Electrochemical formation of Al-Tm intermetallics in eutectic LiCl-KCl melt containing Tm and Al ions

    NASA Astrophysics Data System (ADS)

    Li, Xing; Yan, Yong-De; Zhang, Mi-Lin; Tang, Hao; Ji, De-Bin; Han, Wei; Xue, Yun; Zhang, Zhi-Jian

    2014-09-01

    This work focuses on investigating the electrochemical formation of Al-Tm and Al-Li-Tm alloys in LiCl-KCl-AlCl3-Tm2O3 melt on both W and Al electrodes. Thermodynamic calculation and electrochemical behavior of LiCl-KCl melt containing both AlCl3 and Tm2O3 showed that AlCl3 can chlorinate Tm2O3 to release Tm(III) ions. Three kinds of Al-Tm intermetallics at about -1.26, -1.32 and -1.43 V were detected by means of various electrochemical measurement techniques, i.e. cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Potentiostatic and galvanostatic electrolysis were carried out on Al and W electrodes to prepare Al-Tm and Al-Li-Tm alloys, respectively. The composition of Al-Li-Tm alloys was analyzed by inductive coupled plasma atomic emission spectrometer (ICP-AES).

  17. Hydrogen Solubility in Al-bearing Perovskite

    NASA Astrophysics Data System (ADS)

    Watson, H. C.; Krawczynski, M. J.; Fei, Y.

    2005-12-01

    It is generally accepted that silicate perovskite is the dominant mineral in the Earth's lower mantle. Previous studies have been completed to determine the physical and chemical characteristics of the pure end-member MgSiO3. Recent studies have shown that the addition of Al to MgSiO3 can have a significant effect on the material properties of the mineral, such as compressibility, and defect structure, as well as a great potential to dissolve water. We have synthesized Al-bearing perovskite samples under hydrous conditions in a multi-anvil apparatus at pressures ranging from 23-26 GPa and 1800oC. The starting materials consisted of brucite and silica powders mixed together and finely ground in a 1:1 molar ratio, with subsequent addition of Al2O3 powder at 2wt% intervals from 0%-6%. The mixed powders were tightly packed in Au capsules, housed in BN sleeves, and loaded into standard 8/3 multi-anvil assemblies. The experiments were brought to the appropriate pressure conditions for solubility of the different Al2O3 contents. The resulting perovskite crystals range in size from <20 microns to >100 microns in size. Their major element chemistry has been characterized by EPMA, and the H content of some samples has been measured by secondary ion mass spectrometry using a 6f Cameca ion microprobe and is substantial (>1200ppm in some samples). In this study, we correlate H content in the perovskites with Al concentration, and discussion follows on what effects this may have on potential substitution mechanisms, and correlated formation of oxygen vacancies, as well as water storage in the mantle, oxygen diffusion, and the potential of an oxygen ionic diffusion contribution to electrical conductivity in the mantle.

  18. NMR measurements and hybridization behavior in Al_3Zr, Al_3Hf, and related intermetallics

    NASA Astrophysics Data System (ADS)

    Lue Ross, Chin Shan, Jr.

    2001-03-01

    We report ^27Al NMR measurements on aluminum-rich intermetallics, including the DO_23-structured alloys Al_3Zr and Al_3Hf, and related close-packed structures. We determined the quadrupole splittings and Knight shifts, giving site-dependent structural information. The Knight shift tensors indicate strong directional bonding in the DO_23 alloys, despite the modified close-pack structures. This is especially true for sites I and III. The non-zero asymmetry factor ? at aluminum site III is related to the shifting of atoms from positions on the (001) lattice planes, which has been proposed to enhance stability in Al_3Zr and Al_3Hf. From site-dependent spin-lattice relaxation times (T_1's) and the Korringa relation we have obtained site-dependent information about the conduction electrons in these materials. T_1's for site III are particularly long, indicating a possible stability mechanism due to hybridization-bap formation. However, the hybridization-gap behavior is not as strong as in the corresponding DO_22 materials such as Al_3V. We compare to measurements for several related Al-rich V and Fe aluminides, and describe NMR results for these materials.

  19. Some TEM observations of Al2O3 scales formed on NiCrAl alloys

    NASA Technical Reports Server (NTRS)

    Smialek, J.; Gibala, R.

    1979-01-01

    The microstructural development of Al2O3 scales on NiCrAl alloys has been examined by transmission electron microscopy. Voids were observed within grains in scales formed on a pure NiCrAl alloy. Both voids and oxide grains grew measurably with oxidation time at 1100 C. The size and amount of porosity decreased towards the oxide-metal growth interface. The voids resulted from an excess number of oxygen vacancies near the oxidemetal interface. Short-circuit diffusion paths were discussed in reference to current growth stress models for oxide scales. Transient oxidation of pure, Y-doped, and Zr-doped NiCrAl was also examined. Oriented alpha-(Al, Cr)2O3 and Ni(Al, Cr)2O4 scales often coexisted in layered structures on all three alloys. Close-packed oxygen planes and directions in the corundum and spinel layers were parallel. The close relationship between oxide layers provided a gradual transition from initial transient scales to steady state Al2O3 growth.

  20. Photoemission Characterization of Al/Alq3 and Al/LiF/Alq3 Interfaces

    NASA Astrophysics Data System (ADS)

    Yan, Li; Le, Q. T.; Gao, Yongli; Mason, M. G.; Tang, C. W.

    2000-03-01

    The interfaces formation of Al on tris-(8-hydroxyquinoline) aluminium Alq3 and Al on LiF/Alq3 is investigated by using X-ray and ultraviolet photoemission spectrascopy (XPS and UPS). We observed significant modification of O1s, N1s and Al2p core level spectra as Al was directly deposited on the Alq3 surface. The Alq3 molecular orbital features in the UPS spectra were also quikly destroyed. In contract, a dramatically different behavior was observed for Al on the LiF/Alq3 interface. With only about 5Åor less of LiF deposited on the Alq3 as a buffer layer, the reaction between Al and Alq3 is significantly suppressed. A well-defined gap state is formed in UPS spectra. The Alq3 molecular orbital features in UPS shift to higher binding energies but remain easily recognizable. Both the core level spectra and the gap state suggest that the Alq3 anion is formed in the presence of Al and LiF.

  1. Ion irradiation induced Al-Ti interaction in nano-scaled Al/Ti multilayers

    NASA Astrophysics Data System (ADS)

    Milosavljevi?, M.; Stojanovi?, N.; Peruško, D.; Timotijevi?, B.; Toprek, D.; Kova?, J.; Draži?, G.; Jeynes, C.

    2012-01-01

    Interactions induced in Al/Ti multilayers by implantation of Ar ions at room temperature were investgated. Initial structures consisted of (Al/Ti) × 5 multilayers deposited by d.c. ion sputtering on Si(1 0 0) wafers, to a total thickness of ?250 nm. They were irradiated with 200 keV Ar+ ions, to the fluences from 5 × 1015 to 4 × 1016 ions/cm2. It was found that ion irradiation induced a progressed intermixing of the multilayer constituents and Al-Ti nanoalloying for the highest applied fluence. The resulting nanocrystalline structure had a graded composition with non-reacted or interdiffused Al and Ti, and ?-AlTi and AlTi3 intermetallic phases. Most intense reactivity was observed around mid depth of the multilayers, where most energy was deposited by the impact ions. It is presumed that Al-Ti chemical reaction is triggered by thermal spikes and further enhanced by chemical driving forces. The applied processing can be interesting for fabrication of tightly bond multilayered structures with gradual changes of their composition and properties.

  2. An Al-inducible MATE gene is involved in external detoxification of Al in rice.

    PubMed

    Yokosho, Kengo; Yamaji, Naoki; Ma, Jian Feng

    2011-12-01

    A number of plant species, including rice, secretes citrate from roots in response to Al stress. Here we characterized the functions of a gene, OsFRDL4 (Os01g0919100) that belongs to the multidrug and toxic compound extrusion (MATE) family in rice (Oryza sativa). Heterologous expression in Xenopus oocyte showed that the OsFRDL4 protein was able to transport citrate and was activated by Al. The expression level of the OsFRDL4 gene in roots was very low in the absence of Al, but was greatly enhanced by Al after short exposure. Furthermore, the OsFRDL4 expression was regulated by ART1, a C2H2-type zinc finger transcription factor for Al tolerance. Transient expression of OsFRDL4 in onion epidermal cells showed that it localized to the plasma membrane. Immunostaining showed that OsFRDL4 was localized in all cells in the root tip. These expression patterns and cell specificity of localization of OsFRDL4 are different from other MATE members identified previously. Knockout of OsFRDL4 resulted in decreased Al tolerance and decreased citrate secretion compared with the wild-type rice, but did not affect citrate concentration in the xylem sap. Furthermore, there is a positive correlation between OsFRDL4 expression level and the amount of citrate secretion in rice cultivars that are differing in Al tolerance. Taken together, our results show that OsFRDL4 is an Al-induced citrate transporter localized at the plasma membrane of rice root cells and is one of the components of high Al tolerance in rice. PMID:21880027

  3. Solidification processing of intermetallic Nb-Al alloys

    NASA Technical Reports Server (NTRS)

    Smith, Preston P.; Oliver, Ben F.; Noebe, Ronald D.

    1992-01-01

    Several Nb-Al alloys, including single-phase NbAl3 and the eutectic of Nb2Al and NbAl3, were prepared either by nonconsumable arc melting in Ar or by zone processing in He following initial induction melting and rod casting, and the effect of the solidification route on the microstructure and room-temperature mechanical properties of these alloys was investigated. Automated control procedures and melt conditions for directional solidification of NbAl3 and the Nb2Al/Nb3Al eutectic were developed; high purity and stoichiometry were obtained. The effects of ternary additions of Ti and Ni are described.

  4. Valence subband coupling effect on polarization of spontaneous emissions from Al-rich AlGaN/AlN quantum wells.

    PubMed

    Lu, Huimin; Yu, Tongjun; Yuan, Gangcheng; Jia, Chuanyu; Chen, Genxiang; Zhang, Guoyi

    2012-12-01

    The optical polarization properties of Al-rich AlGaN/AlN quantum wells (QWs) were investigated using the theoretical model based on the k·p method. Numerical results show that there is valence subband coupling which can influence the peak emission wavelength and emission intensity for TE and TM polarization components from Al-rich AlGaN/AlN QWs. Especially the valence subband coupling could be strong enough when CH1 is close to HH1 and LH1 subbands to modulate the critical Al content switching dominant emissions from TE to TM polarization. It is believed that the valence subband coupling may give important influence on polarization properties of spontaneous emissions and should be considered in designing high efficiency AlGaN-based ultraviolet (UV) LEDs. PMID:23262689

  5. Density of Low-Temperature KF-AlF3 Aluminum Baths with Al2O3 and AlPO4 Additives

    NASA Astrophysics Data System (ADS)

    Vasková, Zuzana; Kontrík, Martin; Mlynáriková, Jarmila; Bo?a, Miroslav

    2015-02-01

    The density of the KF-AlF3 melts of various KF and AlF3 ratio with Al2O3 and AlPO4 addition has been measured using the Archimedean method. On the basis of the obtained density data the molar volumes of the melts were calculated. These molar volumes decrease with concentration of Al2O3 or AlPO4. In the system containing AlPO4, the relation between cryolite ratios (CRs) vs slopes of molar volume trend lines was identified with excellent correlation factor of R 2 = 0.9844, while in the system containing Al2O3 a discontinuity at CR = 2.5 can be observed.

  6. Aplicando Metodos de Aprendizaje Sensible al Coste para Mejorar Problemas de Big Data

    E-print Network

    Granada, Universidad de

    ´ecnicas de miner´ia de datos no est´an bien preparadas para afrontar los requerim- ientos de tiempo y espacio datos y las tecnolog´ias de miner´ia de datos han quedado desbordados por no poder hacer frente a dichas,vlopez,j.m.benitez,herrera}@decsai.ugr.es Abstract. Debido a la explosi´on y proliferaci´on de datos en los ´ultimos a~nos, surge la necesidad de

  7. MATH 22AL Fall 2012 Dr. Dad-del

    E-print Network

    Goldwyn, Eli

    MATH 22AL Fall 2012 Dr. Dad-del Important Information about MAT22A and MAT22AL MATH 22AL is an on line computer lab for MATH 22AL. This course uses MATLAB to reinforce the concepts learned in MATH22A. All MAT 22A students are required to take 22AL, unless they have taken Eng 6 or have a good knowledge

  8. Characterization of Ultrathin Films of -Al2O3 and the Chemistry of 1,3-Butadiene on NiAl(001) and -Al2O3

    E-print Network

    Characterization of Ultrathin Films of -Al2O3 and the Chemistry of 1,3-Butadiene on NiAl(001) and -Al2O3 Michelle M. Ivey, Kathryn A. Layman, Armen Avoyan, Heather C. Allen, and John C. HemmingerVine, California 92697 ReceiVed: October 3, 2002; In Final Form: March 27, 2003 Ultrathin films of -Al2O3 grown

  9. TRANSCRIPTIONAL ANALYSIS BETWEEN TWO WHEAT NEAR-ISOGENIC LINES CONTRASTING IN ALUMINUM (AL) TOLERANCE UNDER AL STRESS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To understand the mechanisms of aluminum (Al) tolerance and identify genes responsible for Al tolerance in wheat (Triticum aestivum L.), suppression subtractive hybridization (SSH) libraries were constructed from Al-stressed roots for two wheat near- isogenic lines (NILs), Chisholm-T (Al-tolerant) a...

  10. (5.5) BRAZING OF METALLIC-INTERMETALLIC LAMINATE (MIL) Ti-6Al-4V/Al3Ti COMPOSITES

    E-print Network

    Meyers, Marc A.

    (5.5) BRAZING OF METALLIC-INTERMETALLIC LAMINATE (MIL) Ti-6Al-4V/Al3Ti COMPOSITES L. Krüger*, F to their excellent specific mechanical properties, metallic-intermetallic laminate (MIL) composites composed of Ti-6Al-4V and Al3Ti intermetallic layers are very attractive candidates in lightweight, high performance

  11. FTIR and 27 Al MAS NMR analysis of the effect of framework Al-and Si-defects

    E-print Network

    Sklenak, Stepan

    Torino, Via P. Giuria 7, 10125 Torino, Italy a r t i c l e i n f o Article history: Received 3 January for analysis of the population of framework Al- and Si-related defective sites. Beside framework Al atoms in regular Td coordination, perturbed Td coordinated Al atoms and partly extra-framework Al species

  12. Gaussian density-functional study for small neutral (Al n ), positive (Al{\\/n +}) and negative (Al{\\/n -}) aluminium clusters ( n=2 5)

    Microsoft Academic Search

    Patrizia Calaminici; Nino Russo; Marirosa Toscano

    1995-01-01

    The structures and properties of Al n , Al{\\/n +}, Al{\\/n -} ( n=1,5) clusters have been investigated by using the Linear Combination of Gaussian Type Orbitals (LCGTO) method, considering Local (LSD) and Non Local (NLSD) Spin Density Approximations and employing a Model Core Potential (MCP) that allows the explicit treatment of 3 s 2 3 p 1 valence electrons.

  13. The evolution of Al-Azhar Street, Al-Qahira, Egypt

    E-print Network

    Elkatsha, Markus Fawzy Fahmy

    2000-01-01

    The historic quarter of Cairo, al-Qahira, is going through a period intense transformation that is threatening the physical environment as well as the social and economic fabric of the city. The transformations taking place ...

  14. Fabrication and properties of functionally graded NiAl/Al2O3 composites

    NASA Technical Reports Server (NTRS)

    Miller, D. P.; Lannutti, J. J.; Noebe, R. D.

    1993-01-01

    A modified sedimentation process was used in the production of a functionally gradient material (FGM), NiAl/Al2O3. A simple finite element model was used to guide our design and fabrication efforts by estimating residual stress states as a function of composite structure. This approach could lead to tailored designs that enhance or avoid specific residual stress states. Thermal cycling tests were factored into the model to predict time dependent or steady-state internal temperature and stress profiles. Four-point bend tests were conducted to establish the mechanical load-displacement behavior of a single interlayer FGM at room temperature, 800 and 1000 K. Room temperature bend strength of the FGM was 3-4 times that of the base NiAl. At elevated temperatures, composite fracture occurred in a gradual, noncatastrophic mode involving NiAl retardation of a succession of cracks originating in the alumina face.

  15. Rechargeable Al/Cl2 battery with molten AlCl4/-/ electrolyte.

    NASA Technical Reports Server (NTRS)

    Holleck, G. L.; Giner, J.; Burrows, B.

    1972-01-01

    A molten salt system based on Al- and Cl2 carbon electrodes, with an AlCl3 alkali chloride eutectic as electrolyte, offers promise as a rechargeable, high energy density battery which can operate at a relatively low temperature. Electrode kinetic studies showed that the electrode reactions at the Al anode were rapid and that the observed passivation phenomena were due to the formation at the electrode surface of a solid salt layer resulting from concentration changes on anodic or cathodic current flow. It was established that carbon electrodes were intrinsically active for chlorine reduction in AlCl3-alkali chloride melts. By means of a rotating vitreous carbon disk electrode, the kinetic parameters were determined.

  16. Communication Support for People with ALS

    PubMed Central

    Beukelman, David; Fager, Susan; Nordness, Amy

    2011-01-01

    Almost all people with amyotrophic lateral sclerosis (ALS) experience a motor speech disorder, such as dysarthria, as the disease progresses. At some point, 80 to 95% of people with ALS are unable to meet their daily communication needs using natural speech. Unfortunately, once intelligibility begins to decrease, speech performance often deteriorates so rapidly that there is little time to implement an appropriate augmentative and alternative communication (AAC) intervention; therefore, appropriate timing of referral for AAC assessment and intervention continues to be a most important clinical decision-making issue. AAC acceptance and use have increased considerably during the past decade. Many people use AAC until within a few weeks of their deaths. PMID:21603029

  17. Stress evolution during ultrasonic Al ribbon bonding

    NASA Astrophysics Data System (ADS)

    Ando, Masaya; Takashima, Kazumasa; Maeda, Masakatsu; Takahashi, Yasuo

    2014-08-01

    The present study reveals the stress distribution in the substrate during ultrasonic bonding. The deformations of the Si substrate, Al ribbon, and Al pad were numerically analyzed using a finite element method. Experimental observation of the interface using a highspeed video camera was also conducted to determine the actual interfacial slip amplitude. This amplitude becomes smaller than that of tool-tip with bonding time. It was suggested from the numerical simulations that frictional adhesion enhanced the friction force, resulting in an increase in the equivalent stress in the ribbon and pad. As a result, very large stresses occur in the substrate during ultrasonic bonding. These stresses evolve with the progress of ultrasonic bonding, i.e., frictional adhesion.

  18. Quasielastic scattering in PrAl3

    NASA Astrophysics Data System (ADS)

    Goossens, D. J.; Kennedy, S. J.; Hicks, T. J.

    1998-04-01

    Using the long-wavelength polarisation analysis neutron spectrometer (LONGPOL) fitted with time-of-flight energy analysis, the crystal field excitation spectrum of the rare earth trialuminide PrAl3 was measured, and transitions of 4.5 and 3.7 meV were observed to take place between states of the Pr3+ ion. In addition, the neutron polarisation analysis of the elastic scattering resulted in a clearer separation into nuclear elastic and magnetic quasielastic components, the latter resulting from the neutrons' interaction with excited Pr3+ ions. Calculations of transition probabilities were performed, and this led to the conclusion that the quasielastic scattering and crystal field transitions had been successfully observed and distinguished from other scattering events in PrAl3.

  19. Status of the AlCap experiment

    E-print Network

    Litchfield, R Phillip

    2015-01-01

    The AlCap experiment is a joint project between the COMET and Mu2e collaborations. Both experiments intend to look for the lepton-flavour violating conversion $\\mu + A \\rightarrow e + A$, using tertiary muons from high-power pulsed proton beams. In these experiments the products of ordinary muon capture in the muon stopping target are an important concern, both in terms of hit rates in tracking detectors and radiation damage to equipment. The goal of the AlCap experiment is to provide precision measurements of the products of nuclear capture on Aluminium, which is the favoured target material for both COMET and Mu2e. The results will be used for optimising the design of both conversion experiments, and as input to their simulations. Data was taken in December 2013 and is currently being analysed.

  20. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1979-01-01

    Cold pressing and sintering techniques were used to produce ceramic test specimens in which the major phase was either Si3N4 or a solid solution having the beta Si3N4 structure. Additional components were incorporated to promote liquid phase sintering. Glass and/or crystalline phase were consequently retained in boundaries between Si3N4 grains which largely determined the physical properties of the bodies. Systems investigated most extensively included R-Si-Al-O-N (R = rare earth element) Zr-Si-Al-O-N, Y-Si-Be-O-N, and R1-R2-Si-O-N. Room temperature and 1370 C modulus of ruptured, 1370 C creep, and oxidation behavior are discussed in terms of phase relationships in a parent quinery, and relavent oxide systems.

  1. Observable Proxies For 26 Al Enhancement

    SciTech Connect

    Fryer, Christopher L [Los Alamos National Laboratory; Young, Patrick A [Los Alamos National Laboratory; Ellinger, Carola I [ASU; Arnett, William D [UNIV ARIZONA

    2008-01-01

    We consider the cospatial production of elements in supernova explosions to find observationally detectable proxies for enhancement of {sup 26}Al in supernova ejecta and stellar systems. Using four progenitors we explore a range of 1D explosions at different energies and an asymmetric 3D explosion. We find that the most reliable indicator of the presence of {sup 26}Al in unmixed ejecta is a very low S/Si ratio ({approx} 0.05). Production of N in O/S/Si-rich regions is also indicative. The biologically important element P is produced at its highest abundance in the same regions. Proxies should be detectable in supernova ejecta with high spatial resolution multi wavelength observations, but the small absolute abundance of material injected into a proto-planetary disk makes detection unlikely in existing or forming stellar/planetary systems.

  2. Diffusion in single crystal of melilite: interdiffusion of Al + Al vs. Mg + Si

    Microsoft Academic Search

    H. Nagasawa; T. Suzuki; M. Ito; M. Morioka

    2001-01-01

    Interdiffusion coefficients of Al + Al vs. Mg + Si in the gehlenite–åkermanite system of melilite were determined by coupled\\u000a annealing of synthesized end-member single crystals. The observed diffusion coefficients for a couple-annealed sample vary\\u000a for about 2 orders of magnitude, showing strong dependence on the gehlenite–åkermanite composition: diffusion coefficient\\u000a observed at 1350 °C, for example, is 3 × 10?13

  3. Defect Band Characteristics in Mg-Al and Al-Si High-Pressure Die Castings

    Microsoft Academic Search

    C. M. Gourlay; H. I. Laukli; A. K. Dahle

    2007-01-01

    Bands of positive macrosegregation and porosity commonly follow the surface contour of components produced by high-pressure\\u000a die casting (HPDC). In this article, Al alloy AlSi7Mg and Mg alloys AZ91 and AM60 were cast into tensile test bars using cold-chamber\\u000a (cc) HPDC. Microstructural characterization revealed that externally solidified crystals (ESCs) are not necessary for defect\\u000a band formation, and that defect bands

  4. Defect Band Characteristics in Mg-Al and Al-Si High-Pressure Die Castings

    Microsoft Academic Search

    C. M. Gourlay; H. I. Laukli; A. K. Dahle

    2007-01-01

    Bands of positive macrosegregation and porosity commonly follow the surface contour of components produced by high-pressure die casting (HPDC). In this article, Al alloy AlSi7Mg and Mg alloys AZ91 and AM60 were cast into tensile test bars using cold-chamber (cc) HPDC. Microstructural characterization revealed that externally solidified crystals (ESCs) are not necessary for defect band formation, and that defect bands

  5. GaN on Si Substrate with AlGaN\\/AlN Intermediate Layer

    Microsoft Academic Search

    Hiroyasu Ishikawa; Guang-Yuan Zhao; Naoyuki Nakada; Takashi Egawa; Takashi Jimbo; Masayoshi Umeno

    1999-01-01

    A single crystal GaN thin film was successfully grown on a Si (111) substrate by means of atmospheric pressure metalorganic chemical vapor deposition. Though there is a large difference in thermal expansion coefficients between GaN and Si, an intermediate layer consisting of AlN and AlGaN improved the quality of GaN on Si and reduced meltback etching during growth. Pits and

  6. Electronic and magnetic properties of AlFe 3 and AlFe 3N nitride

    Microsoft Academic Search

    C. A. Kuhnen; A. V. dos Santos

    2004-01-01

    Self-consistent band structure calculations were performed for the metal aluminide AlFe3 (in the fcc structure) and the nitride AlFe3N (perovskite-like nitride) at several lattice parameters in order to obtain the electronic structure and magnetic properties of these compounds. In this study we have employed the full potential linear augmented plane wave (FPLAPW) and the linear muffin-tin orbital (LMTO-ASA) methods. Our

  7. Drilling of Al—Mg—Cu alloys and Al—Mg—Cu\\/SiC composites

    Microsoft Academic Search

    Abdalla Alrashdan; Ahmad T. Mayyas; Adel Mahamood Hassan; Mohammed T. Hayajneh

    2011-01-01

    Metal matrix composites are widely used in engineering applications including automotive, aircraft, and military industries. In this study, different Al—4 wt%Mg—Cu alloys, and Al—4 wt%Mg—Cu\\/SiC composites were drilled on a vertical drilling machine using moderate speed and general purpose high-speed steel tools. The machinability parameters studied in this research were drilling forces (torque and thrust force) and surface roughness of

  8. Differential corticospinal tract degeneration in homozygous ‘D90A’ SOD1 ALS and sporadic ALS

    Microsoft Academic Search

    C R V Blain; S Brunton; V C Williams; A Leemans; M R Turner; P M Andersen; M Catani; B R Stanton; J Ganesalingham; D K Jones; S C R Williams; P N Leigh; A Simmons

    2011-01-01

    BackgroundThe homogeneous genotype and stereotyped phenotype of a unique familial form of amyotrophic lateral sclerosis (ALS) (patients homozygous for aspartate-to-alanine mutations in codon 90 (homD90A) superoxide dismutase 1) provides an ideal model for studying genotype\\/phenotype interactions and pathological features compared with heterogeneous apparently sporadic ALS. The authors aimed to use diffusion tensor tractography to quantify and compare changes in the

  9. DX centers in AlAs and GaAs-AlAs selectively doped superlattices

    NASA Astrophysics Data System (ADS)

    Ababou, S.; Marchand, J. J.; Mayet, L.; Guillot, G.; Mollot, F.

    1991-07-01

    DX centers have been investigated using deep level transient spectroscopy (DLTS) in Si doped AlAs and in selectively doped GaAs-AlAs superlattices (SLs) grown by molecular beam epitaxy. The activation energy for thermal emission is E_a = 0.42 eV in both the SLs and AlAs layers. For the first time a study of the capture in a SL reveals a capture activation energy E_cap = 0.36 cV, which locates the DX at E_t? 60 meV below the conduction miniband. Taking into account the measured energies and trap concentrations, we show that the DX observed in the SLs lies in the AlAs layers. Des mesures de spectroscopie capacitives effectuées sur AlAs et sur des super-réseaux (SR) GaAs-AlAs dopés sélectivement et épitaxiés par jets moléculaires montrent que le centre DX a une énergie apparente E_a = 0.42 eV aussi bien dans AlAs que dans les SR. Pour la première fois, une étude de la capture menée sur un SR nous permet de remonter à l'énergie d'activation de la section efficace de capture qui est dans notre cas de 0.36 eV, ce qui positionne le DX à E_t? 60 meV de la minibande de conduction. La nature et la position de DX sont discutées en tenant compte de l'énergie et de la concentration du DX pour chaque structure, et nous montrons que le DX observé est lié au silicium dans les couches AlAs.

  10. Structure and ductility of TiAl

    SciTech Connect

    Imayev, R.; Salishchev, G.; Imayev, V.; Shagiev, M.; Kuznetzov, A. [Inst. for Metals Superplasticity Problems, Ufa (Russian Federation)

    1995-12-31

    The effect of structural factors (grain size and grain boundary structure) and strain rate on the deformation mechanism and ductility of TiAl in the temperature range of brittle-to-ductile transition and at room temperature was systematically investigated. It has been established that it is possible to substantially affect the deformation mechanism and ductility of this intermetallic by controlling structural factors, particularly the grain size, and varying the strain rate.

  11. Euklid als Physiker: Die Realgeltung der Geometrie

    NASA Astrophysics Data System (ADS)

    Genz, Henning

    Es lässt sich beweisen, dass die Winkelsumme in einem ebenen, euklidischen Dreieck 180 Grad beträgt. Ebenso ergibt sich, dass die Winkelsumme in einem Dreieck auf einer Kugeloberfläche größer als 180 Grad ist. Auch der Satz des Pythagoras ist beweisbar. In allen Fällen beruhen die Beweise auf Euklids Parallelenaxiom. Das aber lässt sich nicht beweisen. Beweisbar aber ist, dass es in nicht-euklidischen Geomerien nicht gilt.

  12. INTRODUCCION AL LENGUAJE PROLOG 1. Introduccion 2

    E-print Network

    Camacho, David

    . Prolog y el paradigma de la Programaci´on L´ogica 6 3.1. Sintaxis´on En este documento se realiza una breve introducci´on al lenguaje de programaci´on Prolog, con el objetivo fundamental de mostrar c´omo se da el paso desde el concepto de programaci´on l´ogica "pura

  13. United States Patent [19] Carlson et al.

    E-print Network

    Adelson, Edward

    United States Patent [19] Carlson et al. [11] Patent Number: 4,523,230 [45] Date of Patent: Jun. 11 ............. 358/160, 163; 166; 167, 358/905, 21 R, 36; 382/49, 54 [56] References Cited U.S. PATENT DOCUMENTS 4 signals. 24 Claims, 8 Drawing Figures #12;U.S. Patent Jun. 11, 1985 Sheet 1 of 4 4,523,230 #12;U.S. Patent

  14. United States Patent [19] Burt et al.

    E-print Network

    Adelson, Edward

    United States Patent [19] Burt et al. [11] Patent Number: 4 , 6 98, 84 3 [45] Date of Patent: Oct, 43, 49, 50, 54, 55 [56] References Cited U.S. PATENT DOCUMENTS 3,737,855 6/1973 Cutaia.S. Patent Oct. 6, 1987 Sheet 1 of 3 4,698,843 #12;U.S. Patent Oct. 6, 1987 Sheet 2 of 3 4,698,843 #12;U

  15. Al Backlighter Characterization at the Omega Laser

    Microsoft Academic Search

    Jim Cobble

    2005-01-01

    We have characterized He- and H-like Al emission for various laser illuminations at the Omega laser with the goal of optimizing the ability to backlight low-atomic-number (low-Z) materials such as beryllium for fusion ignition studies. The conversion efficiency to Lyman alpha at 1.73 keV has been determined for 1, 2, 4, and 7 laser beams, i.e., as a function of

  16. ACCURATE BUILDING OUTLINES FROM ALS DATA

    Microsoft Academic Search

    Building detection from airborne laser scanner (ALS) data is a well-studied problem. Most existing building detection techniques rely on the generation of a digital terrain model (DTM) and a digital surface model (DSM) from last-pulse laser scanner data. The two are compared to form a normalised DSM (nDSM), from which the buildings are detected by use of a simple height

  17. Semiconducting Al transition-metal quasicrystals

    Microsoft Academic Search

    M. Krajcí; J. Hafner

    2003-01-01

    We report on a class of icosahedral aluminum transition-metal (Al-TM) alloys with true semiconducting behavior. Our description of the structure of these icosahedral quasicrystals is based on the six-dimensional Katz-Gratias-Boudard (KGB) model of the face-centered-icosahedral (fci) quasicrystal and its rational approximants. The shell structure of the atomic surfaces in perpendicular space defines the chemical order of aluminum and transition-metal (TM)

  18. Roll Casting of Al25%Si

    Microsoft Academic Search

    Toshio Haga; Hideto Harada; Hisaki Watari

    2011-01-01

    Strip casting of Al-25%Si strip was tried using an unequal diameter twin roll caster. The diameter of the lower roll (large roll) was 1000 mm and the diameter of the upper roll (small roll) was 250 mm. Roll material was mild steel. The sound strip could be cast at the speeds ranging from 8 m\\/min to 12 m\\/min. The strip

  19. Redistribution of Ti and Al in deuterium charged TiAl

    SciTech Connect

    Legzdina, D.; Robertson, I.M.; Birnbaum, H.K. (Illinois, University, Urbana (United States))

    1992-06-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration. 10 refs.

  20. Softening Kinetics in High Al and High Al-Nb-Microalloyed Steels

    NASA Astrophysics Data System (ADS)

    Pereda, B.; Aretxabaleta, Z.; López, B.

    2015-03-01

    Double-hit torsion tests were performed in order to study the effect of high Al levels (up to 2 wt.%) and Nb microalloying (up to 0.07 wt.%) on the static softening kinetics of 0.2%C-2%Mn steels. The addition of 1%Al leads to a delay in the softening kinetics due to solute-drag effect, equivalent to that exerted by 0.027%Nb. For the 2%Al steels, at temperatures below 1000 °C, ? ? ? phase transformation occurs after deformation, resulting in a larger retardation of the softening kinetics. At temperatures higher than 1000 °C, Nb in solid solution also contributes to the retardation of the static softening kinetics, and at lower temperatures NbC strain-induced precipitation leads to incomplete softening for the 1%Al steel, and to a complex interaction between softening, phase transformation, and NbC strain-induced precipitation for the 2%Al-Nb steels. The effect of Al on the static softening kinetics was quantified and introduced in a model developed in previous works for the prediction of the austenite microstructural evolution. In order to validate the results of the model, multipass torsion tests were carried out at conditions representative of hot strip and plate rolling mills. Model predictions show reasonable agreement with the results obtained at different deformation conditions.

  1. Influence of Al fraction on photoemission performance of AlGaN photocathode.

    PubMed

    Hao, Guanghui; Chang, Benkang; Shi, Feng; Zhang, Junju; Zhang, Yijun; Chen, Xinlong; Jin, Muchun

    2014-06-10

    To research the photoemission performance of a transmission-mode Al(1-x)Ga(x)N photocathode, Al0.24Ga0.76N and GaN photocathodes with the same structure were activated, their spectral responses were measured using a multi-information measurement system at room temperature, and the photocathode parameters were obtained by fitting quantum efficiency curves. The results showed that both the reflective-mode and transmission-mode spectral responses of the AlGaN photocathode were lower than those of the GaN photocathode. Compared with the GaN photocathode, the short-wavelength spectral response of the Al0.24Ga0.76N photocathode was less seriously affected by lattice defects between the buffer and emission layers. The Al atom at the AlGaN photocathode surface could affect the optimal Cs adsorption position, which mainly affects the surface electron escape probability of the photocathode. PMID:24921126

  2. A comparative wear study on Al-Li and Al-Li/SiC composite

    SciTech Connect

    Okumus, S. Cem, E-mail: cokumus@sakarya.edu.tr; Karslioglu, Ramazan, E-mail: cokumus@sakarya.edu.tr; Akbulut, Hatem, E-mail: cokumus@sakarya.edu.tr [Sakarya University Engineering Faculty, Department of Metallurgical and Materials Engineering, Esentepe Campus, 54187, Sakarya (Turkey)

    2013-12-16

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al{sub 2}O{sub 3} ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms{sup ?1} and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  3. A comparative wear study on Al-Li and Al-Li/SiC composite

    NASA Astrophysics Data System (ADS)

    Okumus, S. Cem; Karslioglu, Ramazan; Akbulut, Hatem

    2013-12-01

    Aluminum-lithium based unreinforced (Al-8090) alloy and Al-8090/SiCp/17 vol.% metal matrix composite produced by extrusion after spray co-deposition. A dry ball-on disk wear test was carried out for both alloy and composite. The tests were performed against an Al2O3 ball, 10 mm in diameter, at room temperature and in laboratory air conditions with a relative humidity of 40-60%. Sliding speed was chosen as 1.0 ms-1 and normal loads of 1.0, 3.0 and 5.0 N were employed at a constant sliding distance of 1000 m. The wear damage on the specimens was evaluated via measurement of wear depth and diameter. Microstructural and wear characterization was carried out via scanning electron microscopy (SEM). The results showed that wear loss of the Al-8090/SiC composite was less than that of the Al-8090 matrix alloy. Plastic deformation observed on the wear surface of the composite and the matrix alloy, and the higher the applied load the greater the plastic deformation. Scanning electron microscopy examinations of wear tracks also reveal that delamination fracture was the dominant wear mechanism during the wear progression. Friction coefficient was maximum at the low applied load in the case of the Al-8090/SiC composite while a gradual increase was observed with applied load for the matrix alloy.

  4. Room Temperature Radiolytic Synthesized Cu@CuAlO2-Al2O3 Nanoparticles

    PubMed Central

    Abedini, Alam; Saion, Elias; Larki, Farhad; Zakaria, Azmi; Noroozi, Monir; Soltani, Nayereh

    2012-01-01

    Colloidal Cu@CuAlO2-Al2O3 bimetallic nanoparticles were prepared by a gamma irradiation method in an aqueous system in the presence of polyvinyl pyrrolidone (PVP) and isopropanol respectively as a colloidal stabilizer and scavenger of hydrogen and hydroxyl radicals. The gamma irradiation was carried out in a 60Co gamma source chamber with different doses up to 120 kGy. The formation of Cu@CuAlO2-Al2O3 nanoparticles was observed initially by the change in color of the colloidal samples from colorless to brown. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of bonds between polymer chains and the metal surface at all radiation doses. Results of transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX), and X-ray diffraction (XRD) showed that Cu@CuAlO2-Al2O3 nanoparticles are in a core-shell structure. By controlling the absorbed dose and precursor concentration, nanoclusters with different particle sizes were obtained. The average particle diameter increased with increased precursor concentration and decreased with increased dose. This is due to the competition between nucleation, growth, and aggregation processes in the formation of nanoclusters during irradiation. PMID:23109893

  5. Redistribution of Ti and Al in deuterium charged TiAl

    NASA Technical Reports Server (NTRS)

    Legzdina, D.; Robertson, I. M.; Birnbaum, H. K.

    1992-01-01

    The redistribution of titanium and aluminum in a single-phase TiAl alloy that has been exposed to a high pressure of deuterium gas at high temperature is studied. The microstructure in the as-received, uncharged condition consisted of single-phase gamma TiAl grains and a random distribution of precipitates. Precipitates were distributed throughout the matrix and along the grain boundaries. The chemistry of the precipitates varied considerably; some were rich in Al, while other were mostly Ti with some Si and Al. The dislocation density in most grains was low, although in a few grains a high dislocation density was observed. FCC deuterides with a lattice parameter of 0.45 nm form in a Ti-52.1Al-2.1Ta (at. pct) alloy after exposure to 1.38 MPa of deuterium gas at 650 C for 213 hr. The structure and lattice parameter are consistent with the formation of Ti(l)D2. The deuterides that form in this alloy are enriched in Ti and deficient in Al and Ta compared to the deuteride-free matrix. Regions of the matrix contiguous with the deuterides have a correspondingly enhanced aluminum and tantalum concentration.

  6. Reactive HIPIMS with auxiliary Al electrode for ZnO:Al thin film deposition

    NASA Astrophysics Data System (ADS)

    Tiron, Vasile; Costin, Claudiu; Sirghi, Lucel; Popa, Gheorghe

    2012-09-01

    In this paper a new technique is proposed for precise doping control of ZnO:Al thin films deposited in reactive High Power Impulse Magnetron Sputtering (HIPIMS). An auxiliary aluminum electrode was added to a reactive Ar/O2 pulsed magnetron with planar Zn target in order to obtain a controlled doping of ZnO films. Al neutral density in gas phase has been controlled by the discharge current and the biasing voltage on the auxiliary electrode (which influence the ion bombardment of the electrode) and measured by laser resonant absorption spectroscopy. The fraction of Al dopant in the deposited films was estimated by X-ray Photoelectron Spectroscopy (XPS) measurements. The goal of this work was to correlate Al density measured in the gas phase with Al concentration in the deposited films. It was also investigated the effect of the aluminum concentration on the structural, electrical and optical properties of ZnO:Al thin films deposited by HIPIMS. The internal microstructure and chemical composition of the deposited films was examined by X-ray difractometry (XRD) and X-ray Photoelectron Spectroscopy (XPS). The optical properties of the deposited films were studied by UV/VIS and photoluminescence spectroscopy.

  7. TEM and HRTEM Characterization of TiAl Diffusion Bonds Using Ni/Al Nanolayers.

    PubMed

    Simões, Sónia; Viana, Filomena; Ramos, Ana S; Vieira, Maria T; Vieira, Manuel F

    2015-02-01

    Diffusion bonding of TiAl alloys can be enhanced by the use of reactive nanolayer thin films as interlayers. Using these interlayers, it is possible to reduce the conventional bonding conditions (temperature, time, and pressure) and obtain sound and reliable joints. The microstructural characterization of the diffusion bond interfaces is a fundamental step toward understanding and identifying the bonding mechanisms and relating them to the strength of the joints. The interface of TiAl samples joined using Ni/Al nanolayers was characterized by transmission electron microscopy and scanning transmission electron microscopy. Microstructural characterization of the bond revealed that the interfaces consist of several thin layers of different composition and grain size (nanometric and micrometric). The bonding temperature (800, 900, or 1,000°C) determines the grain size and thickness of the layers present at the interface. Phase identification by high-resolution transmission electron microscopy combined with fast Fourier transform and electron energy-loss spectroscopy analyses reveals the presence of several intermetallic compounds: AlTiNi, NiAl, and Al2TiNi. For bonds produced at 800 and 900°C, nanometric grains of Ti were detected at the center of the interface. PMID:25170561

  8. Fabrication of NiAl Microreactors

    SciTech Connect

    Alman, D.E.; Wilson, R.D.; Dewey, T. (Oregon State Univ., Corvallis, OR); Paul, B.K. (Oregon State Univ., Corvallis, OR)

    2000-07-01

    Chemical microreactors offer opportunities for portable powder generation, on-site waste remediation, point-of-use chemical synthesis, and heat-transfer. The material requirements for this application include chemical inertness and the ability to be fabricated into structures that contain internal features of complex geometries and small (<250 ?m) dimensions. It has been recognized that materials with limited formability, like ceramics and intermetallics, will be required for high temperature applications. Reactors from these materials have been produced from powder tapes. However, problems associated with binder removal and sintering result in dimensional instability of the internal geometry which degrades the performance of the reactor. In this paper, a method for forming an array of internal microchannels in a NiAl device that avoids the dimensional instability of powder processing is demonstrated. Microchannels are precision machined (via laser ablation) into elemental Ni and Al foils. During bonding, the foils are converted into NiAl. Results show that this is a viable method for producing aluminide-based structures containing complex, internal features.

  9. KCAT, Xradia, ALS and APS Performance Summary

    SciTech Connect

    Waters, A; Martz, H; Brown, W

    2004-09-30

    At Lawrence Livermore National Laboratory (LLNL) particular emphasis is being placed on the nondestructive characterization (NDC) of components, subassemblies and assemblies of millimeter-size extent with micrometer-size features (mesoscale). These mesoscale objects include materials that vary widely in composition, density, geometry and embedded features. Characterizing these mesoscale objects is critical for corroborating the physics codes that underlie LLNL's Stockpile Stewardship mission. In this report we present results from our efforts to quantitatively characterize the performance of several x-ray systems in an effort to benchmark existing systems and to determine which systems may have the best potential for our mesoscale imaging needs. Several different x-ray digital radiography (DR) and computed tomography (CT) systems exist that may be applicable to our mesoscale object characterization requirements, including microfocus and synchrotron systems. The systems we have benchmarked include KCAT (LLNL developed) and Xradia {mu}XCT (Xradia, Inc., Concord, CA), both microfocus systems, and Beamline 1-ID at the Advance Photon Source (APS) and the Tomography Beamline at the Advanced Light Source (ALS), both synchrotron based systems. The ALS Tomography Beamline is a new installation, and the data presented and analyzed here is some of the first to be acquired at the facility. It is important to note that the ALS system had not yet been optimized at the time we acquired data. Results for each of these systems has been independently documented elsewhere. In this report we summarize and compare the characterization results for these systems.

  10. Solidification Behavior of gamma'-Ni3Al Containing Alloys in the Ni-Al-O System

    NASA Technical Reports Server (NTRS)

    Copland, Evan

    2007-01-01

    The chemical activities of Al and Ni in gamma(prime)-Ni3Al-containing systems were measured using the multi-cell Knudsen effusion-cell mass spectrometry technique (multi-cell KEMS), over the composition range 8 - 32 at.%Al and temperature range T = 1400 - 1750 K. From these measurements a better understanding of the equilibrium solidification behaviour of gamma(prime)-Ni3Al-containing alloys in the Ni-Al-O system was established. Specifically, these measurements revealed that (1) gamma(prime)-Ni3Al forms via the peritectiod reaction, gamma + Beta (+ A12O3) = gamma (prime) (+ Al2O3), at 1633 +/- 1 K, (2) the {gamma + Beta + Al2O3} phase field is stable over the temperature range 1633 through 1640 K, and (3) equilibrium solidification occurs by the eutectic reaction, L (+ Al2O3) = gamma + Beta (+ Al2O3), at 1640 +/- 1 K and a liquid composition of 24.8 +/- 0.2 at.%Al (at an unknown oxygen content). When projected onto the Ni-Al binary, this behaviour is inconsistent with the current Ni-Al phase diagram and a new diagram is proposed. This new Ni-Al phase diagram explains a number of unusual steady-state solidification structures reported previously and provides a much simpler reaction scheme in the vicinity of the gamma(prime)-Ni3Al phase field.

  11. Homoepitaxial growth of AlN layers using by metalorganic vapor phase epitaxy on freestanding AlN substrate

    NASA Astrophysics Data System (ADS)

    Morishita, Tomohiro; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu

    2014-03-01

    We fabricated the homoepitaxial AlN layers and AlGaN/AlN multi-quantum wells (MQWs) grown on freestanding AlN (0001) substrates by metalorganic vapor phase epitaxy. Crystallographic and optical characteristics of these AlN layers and AlGaN/AlN MQWs were investigated by X-ray diffraction (XRD), SEM, AFM, PL, and so on. These characteristics of MQWs are strongly dependent on growth condition of homoepitaxial AlN layer. In case that AlN layers are grown with high temperature and low V/III ratio, there are many hillocks on the surface and no PL signal from MQW. In contrast, strong PL emission cannot be obtained from AlGaN/AlN MQW on AlN layer grown with lower temperature and higher V/III ratio, because this MQW has large surface roughness from results of XRD and AFM measurement. We optimized the growth condition of AlN layers and obtained the high quality AlGaN/AlN MQW with smooth surface, strong PL emission.

  12. Potentiodynamic Polarization Aspects of the As-cast and Sprayed Al-Si, Al-Sn and Al-Sn-Si Alloys in a Sodium Chloride Solution

    NASA Astrophysics Data System (ADS)

    Anil, M.; Balaji, S.; Upadhyaya, A.; Ghosh, M. K.; Ojha, S. N.

    2010-12-01

    The present study compares the corrosion behavior of Al-Sn, Al-Si and Al-Sn-Si alloys processed by spray forming with that of the conventional chill cast ones in aqueous 0.1 N NaCl solution. Spray forming resulted in finer microstructural features with uniform distribution of second-phase particles. The spray formed Al-Si samples showed improved corrosion resistance as compared to the chill cast ones. The Sn containing alloys showed inferior corrosion resistance in the neutral electrolyte. The addition of 12.5 wt.% Si to Al-Sn alloys improves the corrosion resistance.

  13. On the structural development during ultrathin amorphous Al2O3 film growth on Al(111) and Al(100) surfaces by thermal oxidation

    NASA Astrophysics Data System (ADS)

    Flötotto, D.; Wang, Z. M.; Mittemeijer, E. J.

    2015-03-01

    The structural developments during growth of ultrathin amorphous Al2O3 film on bare Al(100) and Al(111) surfaces, by dry thermal oxidation in the oxygen partial pressure range of 1 × 10- 5-1.0 Pa at 300 K, were investigated as function of the oxide-film thickness by (local) chemical state analysis using angle-resolved X-ray photoelectron spectroscopy in combination with low electron energy diffraction and cross-sectional high resolution transmission electron microscopy. The effect of the dielectric discontinuity, at the interfaces of the surficial Al2O3 film has been determined quantitatively and has been subtracted from the observed chemical shifts of the core level photoelectron binding energies as well as from the observed Auger transition kinetic energies. It is revealed that ultrathin amorphous Al2O3 films on the Al(111) and Al(100) surfaces experience remarkably different structural developments upon growth.

  14. Thermal expansion of gehlenite, Ca2Al[AlSiO7], and the related aluminates LnCaAl[Al2O7] with Ln=Tb, Sm

    Microsoft Academic Search

    L. Peters; K. Knorr; M. Knapp; W. Depmeier

    2005-01-01

    The thermal expansion of gehlenite, Ca2Al[AlSiO7], (up to T=830 K), TbCaAl[Al2O7] (up to T=1,100 K) and SmCaAl[Al2O7] (up to T=1,024 K) has been determined. All compounds are of the melilite structure type with space group Pbar {4}2_1 m. Thermal expansion data was obtained from in situ X-ray powder diffraction experiments in-house and at HASYLAB at the Deutsches Elektronen Synchrotron (DESY)

  15. Intermediate temperature thermomechanical processing of Al 2090 for superplasticity

    NASA Technical Reports Server (NTRS)

    Hales, S. J.; Mcnelley, T. R.; Groh, G. E.

    1989-01-01

    The Al-Cu-Li phase diagram indicates that during thermomechanical processing of Al 2090 at 300 C both T(1) and T(2) phases will precipitate. Following work on Al-Mg-X alloys, it is possible that TMP at such temperatures might promote intragranular formation of these phases and promote microstructural refinement during recrystallization. Microstructural analyses reveal that the T(2) phase in Al 2090 may play a similar role to the beta-phase in Al-Mg-X alloys during microstructural evolution. Mechanical property data indicate that Al 2090 can be moderately (215-245 percent) superplastic at 370 C following processing at 300 C.

  16. Al-Ca and Al-Fe metal-metal composite strength, conductivity, and microstructure relationships

    SciTech Connect

    Kim, Hyong June

    2011-12-01

    Deformation processed metal-metal composites (DMMC’s) are composites formed by mechanical working (i.e., rolling, swaging, or wire drawing) of two-phase, ductile metal mixtures. Since both the matrix and reinforcing phase are ductile metals, the composites can be heavily deformed to reduce the thickness and spacing of the two phases. Recent studies have shown that heavily drawn DMMCs can achieve anomalously high strength and outstanding combinations of strength and conductivity. In this study, Al-Fe wire composite with 0.07, 0.1, and 0.2 volume fractions of Fe filaments and Al-Ca wire composite with 0.03, 0.06, and 0.09 volume fractions of Ca filaments were produced in situ, and their mechanical properties were measured as a function of deformation true strain. The Al-Fe composites displayed limited deformation of the Fe phase even at high true strains, resulting in little strengthening effect in those composites. Al-9vol%Ca wire was deformed to a deformation true strain of 13.76. The resulting Ca second-phase filaments were deformed to thicknesses on the order of one micrometer. The ultimate tensile strength increased exponentially with increasing deformation true strain, reaching a value of 197 MPa at a true strain of 13.76. This value is 2.5 times higher than the value predicted by the rule of mixtures. A quantitative relationship between UTS and deformation true strain was determined. X-ray diffraction data on transformation of Al + Ca microstructures to Al + various Al-Ca intermetallic compounds were obtained at the Advanced Photon Source at Argonne National Laboratory. Electrical conductivity was measured over a range of true strains and post-deformation heat treatment schedules.

  17. Study in the interfacial stability of Ti/Al2O3, Ti3Al/Al2O3 and TiAl/Al2O3 composite materials. Final report

    SciTech Connect

    DeKock, J.A.

    1995-12-31

    This thesis is a study of the interfacial stability of the Ti-Base metal matrix composites Ti/Al2O3, Ti3Al/Al2O3 and TiAl/Al2O3. Interfacial stability is discussed in view of the importance of thermodynamics and kinetics as the primary considerations which govern the type of stability observed. From a thermodynamics approach, the application of phase equilibrium diagrams is essential in the design of composite systems. A classification system, with reference to phase equilibrium, is used to describe the type of interfacial stability observed for the composites studied. In addition, electron-probe microanalysis, atom-probe field ion microscopy and X-ray diffraction results are used to establish Ti-Al-O phase relations for the temperature range 900-to-1250 deg C. The kinetics of interfacial stability is discussed with particular attention given to the kinetic considerations; diffusion path, phase formation sequence, steady-state layer growth and interface morphology. Kinetic results in the form of parabolic growth constants and calculated interdiffusion coefficients are presented.

  18. Chemical changes during vermicomposting ( Eisenia fetida ) of sheep manure mixed with cotton industrial wastes

    Microsoft Academic Search

    E. Albanell; J. Plaixats; T. Cabrero

    1988-01-01

    Castings of Eisenia fetida from sheep manure alone and mixed with cotton wastes analysed for their properties and chemical composition every 2 weeks for 3 months and compared with the same manures in the absence of earthworms. The results showed that earthworms accelerated the mineralization rate and converted the manures into castings with a higher nutritional value and degrees of

  19. The influence of feeding patterns on growth and reproduction of the vermicomposting earthworm Eisenia fetida (Oligochaeta)

    Microsoft Academic Search

    A. J. Reinecke; S. A. Viljoen

    1990-01-01

    Observations in outdoor culture beds indicated that food availability and frequency of feeding influenced worm density. In order to study the role of feeding status on the growth and reproduction of Eisenia fetida, pre-clitellate specimens were kept for 180 days under controlled conditions. A control group was regularly provided with freshly produced cattle manure while the experimental groups were fed

  20. Pathogen reduction in septic tank sludge through vermicomposting using Eisenia fetida.

    PubMed

    Rodríguez-Canché, L G; Cardoso Vigueros, L; Maldonado-Montiel, T; Martínez-Sanmiguel, M

    2010-05-01

    This study evaluated the potential of earthworms (Eisenia fetida) to remove pathogens from the sludge from septic tanks. Three earthworm population densities, equivalent to 1, 2, and 2.5kgm(-2), were tested for pathogen removal from sludge. The experimental phase lasted 60days, starting from the initial earthworm inoculation. After 60days, it was found that earthworms reduced concentrations of fecal coliforms, Salmonella spp., and helminth ova to permissible levels (<1000MPN/g, <3MPN/g, and <1viable ova/g on a dry weight basis, respectively) in accordance with Official Mexican Standard of environmental protection (NOM-004-SEMARNAT-2002) (SEMARNAT, 2002). Thus, sludge treatment with earthworms generated Class A biosolids, useful for forest, agricultural, and soil improvement. PMID:20093021

  1. Eisenia fetida (Oligochaeta, Lumbricidae) Activates Fungal Growth, Triggering Cellulose Decomposition During Vermicomposting

    Microsoft Academic Search

    Manuel Aira; Fernando Monroy; Jorge Domínguez

    2006-01-01

    Cellulose is the most abundant polymer in nature and constitutes a large pool of carbon for microorganisms, the main agents responsible for soil organic matter decomposition. Cellulolysis occurs as the result of the combined action of fungi and bacteria with different requirements. Earthworms influence decomposition indirectly by affecting microbial population structure and dynamics and also directly because the guts of

  2. Influence of Reaction with XeF2 on Surface Adhesion of Al and Al2O3 Surfaces

    SciTech Connect

    Zhang, Tianfu; Park, Jeong Y.; Huang, Wenyu; Somorjai, Gabor A.

    2008-07-28

    The change of surface adhesion after fluorination of Al and Al{sub 2}O{sub 3} surfaces using XeF{sub 2} was investigated with atomic force microscopy. The chemical interaction between XeF{sub 2} and Al and Al{sub 2}O{sub 3} surfaces was studied by in situ x-ray photoelectron spectroscopy. Fresh Al and Al{sub 2}O{sub 3} surfaces were obtained by etching top silicon layers of Si/Al and Si/Al{sub 2}O{sub 3} with XeF{sub 2}. The surface adhesion and chemical composition were measured as a function of time after the exposure to air or annealing (at 200 C under vauum). The correlation between the adhesion force increase and presence of AlF{sub 3} on the surface was revealed.

  3. Influence of reaction with XeF2 on surface adhesion of Al and Al2O3 surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Tianfu; Park, Jeong Y.; Huang, Wenyu; Somorjai, Gabor A.

    2008-10-01

    The change in surface adhesion after fluorination of Al and Al2O3 surfaces using XeF2 was investigated with atomic force microscopy. The chemical interaction between XeF2 and Al and Al2O3 surfaces was studied by in situ x-ray photoelectron spectroscopy. Fresh Al and Al2O3 surfaces were obtained by etching top silicon layers of Si /Al and Si /Al2O3 with XeF2. The surface adhesion and chemical composition were measured after the exposure to air or annealing (at 200°C under vacuum). The correlation between the adhesion force increase and presence of AlF3 on the surface was revealed.

  4. Interfacial microstructure and growth mechanism of Al4C3 in Grf/Al composites fabricated by liquid pressure method.

    PubMed

    Xu, Wang; Chenchong, Wang; Zhichao, Zhang; Ping, Liang; Yanhua, Shi; Guofu, Zhang

    2014-10-01

    In this study, Grf/Al composite was fabricated by liquid pressure method. The diffusion layer and the nucleation and growth of Al4C3 were observed at the interface of Grf/Al composites by TEM and HRTEM. The growth mechanism of Al4C3 was analyzed in detail by crystallography theory. It was found that Al4C3 had no phase relations with the carbon fiber. (0001) layer of Al4C3 was parallel with main growth direction. Both the diffusion layer at the interface and crystal structure of Al4C3 affected the shape of Al4C3. At a certain position, Al4C3 could connect two fibers when the fibers were close to each other. PMID:25041826

  5. Characterization of Al2O3 coatings oxidized from Al with different proportion of seed crystals at a lower temperature

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Lin, Yuebin; He, Fei; Luo, Xinyi; Tao, Jie

    2013-10-01

    Al layer with ?-Al2O3 seed crystals was prepared on the surface of 316L stainless steel (SS) by a double cathodes discharge technique, in which the mixed targets of pure Al doped with different proportions of ?-Al2O3 were used. Then, Al2O3 coatings were obtained after plasma oxidization at 580 °C. The phase composition, microstructure and morphology of the coatings were studied respectively by means of glancing-angle (1°) X-ray diffractometry (GAXRD) and scanning electron microscopy (SEM). Furthermore, the bonding force and corrosion resistance of the coatings were measured. The results indicated that ?-Al2O3 nucleated and grew surrounding the seed crystals as the Volmer-Weber Mode. The Al2O3 coating was compact, performing a good corrosion resistance and metallurgical bonding. The inducing effects of ?-Al2O3 with different fractions were discussed. ?-Al2O3 (5.5 wt.%) was distributed in the Al layer when the target possessing 10% ?-Al2O3 was used. After plasma oxidation, 65.54 wt.% ?-Al2O3 was obtained which was 10.34% more than that obtained by the oxidation of pure Al at the same condition. However, the inducing effects became weak with the further increment of content of ?-Al2O3 seed crystals.

  6. Fabrication of Al/Al3Ti Functionally Graded Materials by Reaction Centrifugal Mixed-Powder Method

    NASA Astrophysics Data System (ADS)

    El-Hadad, Shimaa; Sato, Hisashi; Miura-Fujiwara, Eri; Watanabe, Yoshimi

    2011-01-01

    Formation of compositional gradient in Al/Al3Ti Functionally graded materials (FGMs) fabricated by the centrifugal method (CM) depends mainly on the centrifugal force and the processing temperature. In this study, a novel centrifugal method, reaction centrifugal mixed-powder method (RCMPM), was proposed to fabricate Al/Al3Ti FGMs under fixed centrifugal force (G=80). The effects of RCMPM processing temperature on the formation of Al3Ti intermetallics, its morphology and its distribution in the fabricated Al/Al3Ti FGMs have been investigated. Fine granular Al3Ti were observed at relatively lower processing temperature while the known coarse platelet-like particles of Al3Ti could be achieved at higher casting temperatures. Moreover, Ti3Al intermetallics compound and unreacted Ti phases are also observed along with Al3Ti particles. In addition, distribution of Al3Ti intermetallics size and their volume fraction showed a significant change when the Al/Al3Ti FGMs processed at different temperatures relative to the liquidus temperature of the master alloy.

  7. First-principles studies of Al-Ni intermetallic compounds

    SciTech Connect

    Shi Dongmin [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Wen Bin, E-mail: wenbin@dlut.edu.c [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China); Melnik, Roderick [M2NeT Lab, Wilfrid Laurier University, Waterloo, 75 University Ave. West, Ontario, N2L 3C5 (Canada); Yao Shan; Li Tingju [School of Materials Science and Engineering, Dalian University of Technology, Dalian 116023 (China)

    2009-10-15

    The structural properties, heats of formation, elastic properties, and electronic structures of Al-Ni intermetallic compounds are analyzed here in detail by using density functional theory. Higher calculated absolute values of heats of formation indicate a very strong chemical interaction between Al and Ni for all Al-Ni intermetallic compounds. According to the computational single crystal elastic constants, all the Al-Ni intermetallic compounds considered here are mechanically stable. The polycrystalline elastic modulus and Poisson's ratio have been deduced by using Voigt, Reuss, and Hill (VRH) approximations, and the calculated ratio of shear modulus to bulk modulus indicated that AlNi, Al{sub 3}Ni, AlNi{sub 3} and Al{sub 3}Ni{sub 5} compounds are ductile materials, but Al{sub 4}Ni{sub 3} and Al{sub 3}Ni{sub 2} are brittle materials. With increasing Ni concentration, the bulk modulus of Al-Ni intermetallic compounds increases in a linear manner. The electronic energy band structures confirm that all Al-Ni intermetallic compounds are conductors. - Graphical abstract: Calculated bulk modulus compared to experimental and other theoretical values for the Al-Ni intermetallic compounds.

  8. Revisiting the Al/Al2O3 Interface: Coherent Interfaces and Misfit Accommodation

    PubMed Central

    Pilania, Ghanshyam; Thijsse, Barend J.; Hoagland, Richard G.; Lazi?, Ivan; Valone, Steven M.; Liu, Xiang-Yang

    2014-01-01

    We study the coherent and semi-coherent Al/?-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions at the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. Our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/?-Al2O3 composite heterostructures. PMID:24670940

  9. Zirconium adsorption and incorporation on a reconstructed Al-T4 AlN(0001) surface

    NASA Astrophysics Data System (ADS)

    López-Pérez, William; González-Hernández, Rafael; Rodríguez M, Jairo Arbey

    2013-10-01

    We discuss the energetic stability and electronic structure of zirconium adsorption and incorporation on a 2×2 reconstructed AlN(0001) surface. We employ density-functional theory within the generalized-gradient approximation to study such effects. First-principles total energy calculations reveal that the most stable positions of a Zr adatom on the reconstructed 2×2-T4 AlN(0001) surface are at the S1 and Sp substitutional sites. In addition, calculating the relative surface energy of several configurations, we constructed a phase diagram showing the energetically most stable surfaces as a function of the aluminium chemical potential. Based on these results, we find that incorporation at Al-substitutional sites is energetically favorable compared to adsorption on the top layers. In particular, we find that Zr-S1 and Zr-Sp structures are stable over the entire chemical potential range. This effect can lead to the formation of a non-reactive interfacial ZrN(111) layer on the AlN(0001) surface, which can offer a good interfacial combination between AlN substrate and other metal contacts, i.e. zirconium.

  10. ALS 2883: Analysis of spectroscopic features

    NASA Astrophysics Data System (ADS)

    Silva, A. R.; Levenhagen, R. S.; Künzel, R.; Leister, N. V.

    2014-10-01

    ALS 2883 (RA 13^{h} 02^{m} 47^{s}, DEC -63^{o} 50' 08'', M_{v} 10.1) is the first known radio pulsar with an emission B-type companion system, discovered in 1992. The Be companion of ALS 2883 has all line profiles in the visible range in emission. This emission is a common hallmark among many Be stars, and this effect is thought to be due to the presence of a circumstellar environment. Also, the star is orbiting a X-ray source as has been detected by the XMM-Newton Science Operation Center. In this study, we present the observations of ALS 2883 made at the OPD/LNA 1.60 m telescope with the Coudé spectrograph in the range 4000 to 5000 Å and S/N simeq 200, performed in April 2011. First-order estimations of T_{eff} and log g parameters have been performed through Johnson's UBV and JHK photometric calibrations. Projected rotation velocity V sin i has been estimated through the mean of the first zeroes of the Fourier transforms of neutral helium rotation profiles adopting linear, quadratic and square-root limb-darkening laws. The physical conditions of the circumstellar envelope were estimated through the solution of the radiative transport equation assuming local thermodynamic equilibrium within a disk-shaped circumstellar environment with a Keplerian velocity field. The radiative transport equation is solved assuming the Roche model as a boundary condition in the circumstellar environment. Iterating the computations with a downhill-simplex algorithm, this analysis leads to a best solution for an envelope with T simeq 9500 K, gas density ? simeq 2 × 10^{-15} g.cm^{-3}, internal radius r_{i} simeq 8 R_{odot} and external radius r_e simeq 30 R_{odot}, rotating with V_{rot} simeq 140 km.s^{-1} and expanding with V_{exp} simeq 90 km.s^{-1}.

  11. ?-Synuclein Modification in an ALS Animal Model

    PubMed Central

    Yang, Eun Jin; Choi, Sun-Mi

    2013-01-01

    Amyotrophic lateral sclerosis (ALS) is a progressively paralytic neurodegenerative disease that can be caused by mutations in Cu/Zn-superoxide dismutase 1 (SOD1). Transgenic mice that overexpress mutant SOD1 develop paralysis and accumulate aggregates of mutant protein in the brainstem and spinal cord. Bee venom (BV), which is also known as apitoxin, is extracted from honeybees and is commonly used in oriental medicine for the treatment of chronic rheumatoid arthritis and osteoarthritis. The purpose of the present study was to determine whether BV affects misfolded protein aggregates such as alpha-synuclein, which is a known pathological marker in Parkinson disease, and ubiquitin-proteasomal activity in hSOD1G93A mutant mice. BV was bilaterally administered into a 98-day-old hSOD1G93A animal model. We found that BV-treated hSOD1G93A transgenic mice showed reduced detergent-insoluble polymerization and phosphorylation of ?-synuclein. Furthermore, phosphorylated or nitrated ?-synuclein was significantly reduced in the spinal cords and brainstems of BV-treated hSOD1G93A mice and reduced proteasomal activity was revealed in the brainstems of BV-treated symptomatic hSOD1G93A. From these findings, we suggest that BV treatment attenuates the dysfunction of the ubiquitin-proteasomal system in a symptomatic hSOD1G93A ALS model and may help to slow motor neuron loss caused by misfolded protein aggregates in ALS models. PMID:23762114

  12. Transformation to Ni5Al3 in a 63.0 at. pct Ni-Al alloy

    NASA Technical Reports Server (NTRS)

    Khadkikar, P. S.; Locci, I. E.; Vedula, K.; Michal, G. M.

    1993-01-01

    Microstructures of 63 at. pct P/M Ni-Al alloys with a composition close to the stoichiometry of the Ni5Al3 phase were investigated using homogenized and quenched specimens aged at low temperatures for various times. Results of analyses of XRD data and electron microscopy observations were used for quantitative phase analysis, performed to calculate the (NiAl + Ni5Al3)/Ni5Al3 phase boundary locations. The measured lattice parameters of Ni5Al3 phase formed at 823, 873, and 923 K indicated an increase in tetragonality of the phase with increasing nickel content.

  13. Electron mobility enhancement in AlN/GaN/AlN heterostructures with InGaN nanogrooves

    E-print Network

    in AlN/GaN/AlN heterostructures with the shallow InxGa1-xN channel--nanogroove--in the middle consider a narrow groove made of InxGa1-xN with small In content x inside a wurtzite AlN/GaN/AlN heteroN 3 nm /GaN 8 nm /AlN 3 nm QW and in QW with 2 nm wide nanogroove, i.e., AlN 3 nm /GaN 3 nm /InxGa1-xN

  14. Phase equilibria in Al-rich Al-Mg-Sc-Zn alloys at 430 and 300°C

    NASA Astrophysics Data System (ADS)

    Rokhlin, L. L.; Dobatkina, T. V.; Korol'Kova, I. G.

    2008-02-01

    Optical microscopy and X-ray diffraction and electron microprobe analyses are used to study Al-Mg-Sc-Zn alloys annealed at 430 and 300°C. The Al-based solid solution is found to be in equilibrium only with binary and ternary phases of the corresponding systems; these are Al3Sc, ?(Al3Mg2), ?(MgZn2), and ?(Al2Mg3Zn3). Sections are constructed for the isothermal tetrahedra of the Al-Mg-Sc-Zn phase diagram that correspond to a scandium content of 0.5% and magnesium and zinc contents of up to 20%.

  15. Development of SiAlON materials

    NASA Technical Reports Server (NTRS)

    Layden, G. K.

    1977-01-01

    Cold pressing and sintering techniques were used to produce ceramic bodies in which the major phase was beta prime Si3-Al-O-N4 solid solution. A variety of foreign oxides were used to promote liquid phase sintering, and this resulted in the incorporation of additional solid phases in the ceramic bodies which controlled elevated temperature properties. None of the bodies studied to date exhibited both adequate high temperature mechanical properties and oxidation resistance. Criteria are suggested to guide the formulation of bodies with improved high temperature properties.

  16. The structure of extruded NiAl

    NASA Technical Reports Server (NTRS)

    Baker, I.; Schulson, E. M.

    1984-01-01

    The deformation structure of Ni-rich NiAl extruded at 550 C has been characterized by transmission electron microscopy and by optical microscopy. Dislocations having a(100) Burgers vectors were found as complex networks, tangles, and prismatic loops. a(110) dislocations, which were rare, were concluded to arise from reactions of a(100) dislocations. Evidence of recovery and recrystallization was obtained. Extrusion was deemed to have been possible by the operation of (hko)(001) slip systems (often in plane strain flow) plus diffusion-assisted processes.

  17. ALS insertion device block measurement and inspection

    SciTech Connect

    Marks, S.; Carrieri, J.; Cook, C.; Hassenzahl, W.V.; Hoyer, E.; Plate, D.

    1991-05-01

    The performance specifications for ALS insertion devices require detailed knowledge and strict control of the Nd-Fe-B permanent magnet blocks incorporated in these devices. This paper describes the measurement and inspection apparatus and the procedures designed to qualify and characterize these blocks. A detailed description of a new, automated Helmholtz coil facility for measurement of the three components of magnetic moment is included. Physical block inspection and magnetic moment measurement procedures are described. Together they provide a basis for qualifying blocks and for specifying placement of blocks within an insertion devices' magnetic structures. 1 ref., 4 figs.

  18. 75 FR 20773 - Establishment of Class E Airspace; Jackson, AL

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-21

    ...09-ASO-27] Establishment of Class E Airspace; Jackson, AL AGENCY: Federal Aviation Administration (FAA...December 7, 2009 that establishes Class E airspace at Jackson Muni, Jackson, AL. DATES: Effective Date: 0901 UTC, April...

  19. 77 FR 67689 - Fidelity Aberdeen Street Trust, et al.;

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-13

    ...certain repurchase agreements. See Daily Money Fund, et al., Investment...23, 1993) (order), amending, Daily Money Fund, et al., Investment...the Funds in connection with their routine daily cash management activities and...

  20. Epitaxial Zintl aluminide SrAl4 grown on a LaAlO3 substrate

    NASA Astrophysics Data System (ADS)

    Schlipf, Lukas; Slepko, Alexander; Posadas, Agham B.; Seinige, Heidi; Dhamdhere, Ajit; Tsoi, Maxim; Smith, David J.; Demkov, Alexander A.

    2013-07-01

    Zintl phases are a class of intermetallic materials that have simultaneously ionic and covalent bonding resulting from charge transfer between two different atomic species. We present a combined first principles and experimental study of Zintl-phase SrAl4, which is grown in thin film form on the perovskite oxide LaAlO3 using molecular beam epitaxy. The structural properties are investigated using reflection-high-energy electron diffraction, x-ray diffraction, and cross-section transmission electron microscopy, which reveal relaxed epitaxial island growth. Photoelectron spectroscopy measurements verify the Zintl-Klemm nature of the bonding in the material and are utilized to determine the band offset and the work function of SrAl4, while transport measurements confirm its metallic behavior. The experimentally observed properties are confirmed using density functional calculations.

  1. Energy localization on the Al sublattice of Pt3Al with L12 order

    SciTech Connect

    Medvedev, Nikolay N [Altay State Technical University, Russia] [Altay State Technical University, Russia; Starostenkov, Mikhail D [Altay State Technical University, Russia] [Altay State Technical University, Russia; Manley, Michael E [ORNL] [ORNL

    2013-01-01

    A three-dimensional molecular-dynamics model of with order was developed and found to support the excitation of discrete breathers (DBs) and energy localization on the Al sublattice. For an initial lattice temperature of 0 K, large-amplitude DBs polarized along [100] are found to be very weakly damped, retaining most of their initial energy for more than 2000 cycles, while DBs polarized along [111] damped out over ~30 cycles. Because the DBs and their dissipation channels are confined to the Al sublattice, long-lived nonequilibrium states with large energy differences between the Al and Pt sublattices occur. Since collisions during irradiation more efficiently generate lattice vibrations in light atoms than heavy atoms, such nonequilibrium states may occur and alter the relaxation processes occurring during radiation damage.

  2. Reaction diffusion in the NiCrAl and CoCrAl systems

    NASA Technical Reports Server (NTRS)

    Levine, S. R.

    1978-01-01

    The paper assesses the effect of overlay coating and substrate composition on the kinetics of coating depletion by interdiffusion. This is accomplished by examining the constitution, kinetics and activation energies for a series of diffusion couples primarily of the NiCrAl/Ni-10Cr or CoCrAl/Ni-10Cr type annealed at temperatures in the range 1000-1205 C for times up to 500 hr. A general procedure is developed for analyzing diffusion in multicomponent multiphase systems. It is shown that by introducing the concept of beta-source strength, which can be determined from appropriate phase diagrams, the Wagner solution for consumption of a second phase in a semiinfinite couple is successfully applied to the analysis of MCrAl couples. Thus, correlation of beta-recession rate constants with couple composition, total and diffusional activation energies, and interdiffusion coefficients are determined.

  3. Mechanisms of elevated-temperature deformation in the B2 aluminides NiAl and CoAl

    NASA Technical Reports Server (NTRS)

    Yaney, D. L.; Nix, W. D.

    1988-01-01

    A strain rate change technique, developed previously for distinguishing between pure-metal and alloy-type creep behavior, was used to study the elevated-temperature deformation behavior of the intermetallic compounds NiAl and CoAl. Tests on NiAl were conducted at temperatures between 1100 and 1300 K while tests on CoAl were performed at temperatures ranging from 1200 to 1400 K. NiAl exhibits pure-metal type behavior over the entire temperature range studied. CoAl, however, undergoes a transition from pure-metal to alloy-type deformation behavior as the temperature is decreased from 1400 to 1200 K. Slip appears to be inherently more difficult in CoAl than in NiAl, with lattice friction effects limiting the mobility of dislocations at a much higher tmeperature in CoAl than in NiAl. The superior strength of CoAl at elevated temperatures may, therefore, be related to a greater lattice friction strengthening effect in CoAl than in NiAl.

  4. Transformation to Ni5Al3 in a 63.0 At. Pct Ni-Al alloy

    NASA Astrophysics Data System (ADS)

    Khadkikar, P. S.; Locci, I. E.; Vedula, K.; Michal, G. M.

    1993-01-01

    Microstructures in a 63 at. pct Ni-Al alloy, produced by a powder metallurgy process, have been investigated in detail in as-quenched and aged (823 to 923 K) conditions. The parent L10 martensite plus B2 NiAl microstructure in the as-quenched state transformed nearly completely to the orthorhombic Ni5Al3 phase upon aging at 823 K for 720 hours. The volume fraction of Ni5Al3 formed as a function of aging time at 823 K was observed to obey cellular reaction kinetic behavior. The specimens aged at 823 K for short times indicated that nucleation of the Ni5Al3 phase occurred preferentially at grain boundaries. Transmission electron microscopy (TEM) observations of short-time aged specimens revealed a complex microstructure consisting of shortrange ordered domains of Ni2Al in a matrix of 7R martensite, in addition to new variants of 3R martensite and Ni5Al3. Aging at 873 and 923 K for 720 hours produced a stable two-phase microstructure consisting of NiAl and Ni5Al3. A quantitative phase analysis was carried out to calculate the (NiAl + Ni5Al3)/Ni5Al3 phase boundary locations. The measured lattice parameters of Ni5Al3 formed at 823, 873, and 923 K indicated an increase in tetragonality of the phase with increasing nickel content.

  5. A Compliant and Creep Resistant SAC-Al(Ni) Alloy

    Microsoft Academic Search

    Benlih Huang; Hong-Sik Hwang; Ning-Cheng Lee

    2007-01-01

    Addition of Al into SAC alloys reduces the number of hard Ag3Sn and Cu6Sn5 IMC particles, and forms larger, softer non-stoichiometric AlAg and AlCu particles. This results in a significant reduction in yield strength, and also causes some moderate increase in creep rate. For high Ag SAC alloys, adding Al 0.1-0.6% to SAC alloys is most effective in softening, and

  6. Al-Nayrizi's Influence in the West Jan P. Hogendijk

    E-print Network

    Hogendijk, Jan P.

    Al-Nayr¯iz¯i's Influence in the West Jan P. Hogendijk February 14, 2010 1 Introduction Ab¯u'l-c Abb¯as al-Fad.l ibn H. ¯atim al-Nayr¯iz¯i was a mathematician and as- tronomer who originated from the city of Nayr¯iz in Iran and who worked in Baghd¯ad.1 Since he wrote a treatise for Caliph al-Muc tad.id, who

  7. The embrittlement of Al-Zn-Mg and Al-Mg alloys by water vapor

    NASA Astrophysics Data System (ADS)

    Tuck, C. D. S.

    1985-08-01

    Al4.5Zn1.5Mg and Al5Mg were reacted in water-vapor saturated air (WVSA) at 120°C and tensile tested. After an initial loss of ductility with exposure time, probably caused by hydrogen embrittlement of the grain boundaries, between 15 hours and 25 hours exposure the mechanical properties of Al4.5Zn1.5Mg improved, this effect being due both to a reduced corrosion activity of the grain boundaries in producing embrittling hydrogen at the external surface and to grain boundary MgZn2 precipitates acting as hydrogen traps. After 25 hours exposure water was shown to penetrate the grain boundaries, and a layered corrosion product identified as the aluminum hydroxides boehmite and diaspore was formed. This resulted in a marked fall of ductility. Re-solution heat treatment and reaging partially recovered the mechanical properties of Al4.5Zn1.5Mg if the exposure time was less than 50 hours, and would not recover properties for longer exposure times. Small additions (0.1 pct) of iron and nickel to Al4.5Zn1.5Mg lessened the grain boundaries’ sensitivity to corrosive attack whereas the addition of 0.1 pct copper did not. Also, the former two additions did not cause the relative ductility increase during 15 to 25 hours exposure in WVSA at 120°C shown by Al4.5Zn1.5Mg. It is proposed that these elements alter the magnesium segregation levels at the grain boundaries which in turn affects their electrochemical attack.

  8. Antiferromagnetism and magnetoleasticity of UNiAl

    NASA Astrophysics Data System (ADS)

    Sechovský, V.; Honda, F.; Svoboda, P.; Prokeš, K.; Chernyavsky, O.; Doerr, M.; Rotter, M.; Loewenhaupt, M.

    2003-05-01

    We report on a thermal-expansion (TE) and magnetostriction (MS) study of the antiferromagnet UNiAl at temperatures 2- 90 K and in magnetic fields up to 16.5 T applied along the c-axis. The TE along the c-axis (in 0 T) exhibits a broad valley centered around 35 K. This anomaly is nearly removed in 16.5 T. For T?7 K a sharp metamagnetic transition (MT) observed in UNiAl at 11.4 T and it is accompanied by abrupt MS effects of +1.3×10 -4 and -1.8×10 -4 along the a- and c-axis, respectively. In fields above the MT a negligible additional negative MS is induced along c-axis whereas the a-axis and consequently the volume expand considerably, which indicates a field-induced enhancement of the U magnetic moment. T>7 K, the MT becomes gradually smeared out but a non-negligible MS is observed even for T> TN. In the light of these results the TE anomaly measured in zero field may be attributed to AF that survives at temperatures far above TN.

  9. Design and performance of InAlGaAs\\/InAlAs superlattice avalanche photodiodes

    Microsoft Academic Search

    Isao Watanabe; Masayoshi Tsuji; Masako Hayashi; Kikuo Makita; Kenko Taguchi

    1997-01-01

    InAlGaAs-InAlAs superlattice avalanche photodiodes (SL-APD's) have been designed and experimentally analyzed. The layer structures and the electric field profiles were designed for 10 Gb\\/s applications. The mesa-structure SL-APD's exhibited a gain-bandwidth product of 120-150 GHz, a top bandwidth of 15 GHz, and a multiplied dark current of 15-20 nA for a mesa-diameter of 30 ?m. Other characteristics, such as temperature

  10. Inhomogeneous elastic deformation of nanofilms and nanowires of NiAl and FeAl alloys

    NASA Astrophysics Data System (ADS)

    Bukreeva, K. A.; Babicheva, R. I.; Dmitriev, S. V.; Zhou, K.; Mulyukov, R. R.

    2013-09-01

    The molecular dynamics study of the uniaxial tension of nanofilms and nanowires of NiAl and FeAl intermetallide alloys has been performed. It has been shown that such samples are elastically deformed until failure at a strain of ? xx ? 0.35. There is an ? xx interval where the homogeneous deformation is thermodynamically unstable, leading to the formation of domains with different strains. The strain-stress dependence in the thermodynamically unstable region is almost linear, but has different slopes for a nanofilm and a nanowire because of the difference in the dynamics of domain walls.

  11. Time-resolved photoluminescence studies of Al-rich AlGaN alloys

    NASA Astrophysics Data System (ADS)

    Li, Jing; Nam, Ki-Bum; Oder, Tom N.; Kim, KyoungHoon; Nakarmi, M. L.; Lin, Jing Y.; Jiang, Hongxing

    2002-06-01

    Si-doped n-type AlxGa1MINxN alloys with x up to 0.5 and Mg-doped p-type AlxGa1-xN alloys with x up to 0.27 were grown by metal-organic chemical vapor deposition (MOCVD) on sapphire substrates. For the n-type AlxGa1-xN, we achieved highly conductive alloys for x up to 0.5. An electron concentration as high as 1x1018cm-3 was obtained in Si-doped Al0.5Ga0.5N alloys with an electron mobility of 16 cm_2)Vs at room temperature, as confirmed by Hall-effect measurements. Our results also revealed that the conductivity of AlxGa1-xN alloys continuously increases with an increase of Si doping level for a fixed value of Al content (X<0.5), the conductivities of AlxGa1-xN alloys decrease with increasing Al content for a given doping level; the critical Si-doping concentration needed to convert insulating AlxGa1-x)N with high Al contents (X>=0.4) to n- type conductivity is about 1 x 1018cm-3. Time- resolved photoluminescence studies carried out on these materials have shown that Si-doping reduces the effect of carrier localization in AlxGa1-xN alloys and a sharp drop in carrier localization energy occurs when the Si doping concentration increases above 1x1018cm-3, which directly correlates with the observed electrical properties. For the Mg-doped AlxGa1-xN alloys, p-type conduction was achieved for x up to 0.27, as confirmed by variable temperature Hall measurements. Emission lines of band-to-impurity transitions of free electrons with neutral Mg acceptors as well as localized excitons have been observed in the p-type AlxGa1-xN alloys. The Mg acceptor activation energies EA were deduces from photoluminescence spectra and were found to increase with Al content and agreed very well with those obtained by Hall measurements. From the measured activation energy as a function of Al content, EA versus x, the resistivity of Mg-doped AlxGa1-x with high Al contents can be deduced. Our results have also shown that PL measurements provide direct means of obtaining EA especially where this cannot be obtained accurately by electrical methods due to high resistance of p-type AlxGa1-xN with high Al content.

  12. Characterization of Interface Charge in NbAlO/AlGaN/GaN MOSHEMT with Different NbAlO Thicknesses

    NASA Astrophysics Data System (ADS)

    Feng, Qian; Du, Kai; Dai, Bo; Dong, Liang; Feng, Qing

    2015-01-01

    We investigate the influence of interface charge on electrical performance of NbAlO/AlGaN/GaN metal-oxide-semiconductor high electron mobility transistors (MOSHEMTs). Through C—V measurements and simulations, we find that the donor-type interface fixed charge density Qit of 2.2 × 1013 cm?2 exists at the NbAlO/AlGaN interface, which induces the shift of the threshold voltage much more negative. Furthermore, a trap density of approximately 0.43 × 1013–1.14 × 1013 cm?2eV?1 is obtained at the NaAlO/AlGaN interface, which is consistent with the frequency-dependent capacitance and conductance measurement results.

  13. To Ponder Ponderal's Length: A Question to Lester et. al.

    ERIC Educational Resources Information Center

    Scanlon, John W.

    1984-01-01

    Criticizes Lester, Als, and Brazelton's 1982 reanalysis of data presented by Scanlon, Nelson, Grylack, and Smith in 1979. Discusses (1) clinical interpretation of the ponderal index (a weight-for-length ratio); and (2) inaccurate measurement of crown-heel length; (3) Lester et al.'s suggested relationship between the ponderal index, maternal drug,…

  14. Hybrid Silicon Integration R. Jones et al. Hybrid Silicon Integration

    E-print Network

    Bowers, John

    Hybrid Silicon Integration R. Jones et al. 1 / 23 Hybrid Silicon Integration R. Jones1 , H. D. Park.jones@intel.com #12;Hybrid Silicon Integration R. Jones et al. 2 / 23 Hybrid Silicon Integration R. Jones1 , H. D.jones@intel.com Abstract: An overview is presented of the hybrid AlGaInAs-silicon platform that enables wafer level

  15. The Practical Enactment of Adventure Learning: Where Will You AL@?

    ERIC Educational Resources Information Center

    Miller, Brant G.; Hougham, R. Justin; Eitel, Karla Bradley

    2013-01-01

    The Adventure Learning (AL) approach to designing and implementing learning experiences has great potential for practitioners. This manuscript delineates the practical enactment of AL to support the K-12 community, teacher educators, and residential environmental science program providers in the conceptualization and delivery of their own AL…

  16. Constraining oceanic dust deposition using surface ocean dissolved Al

    E-print Network

    Zender, Charles

    Constraining oceanic dust deposition using surface ocean dissolved Al Qin Han,1 J. Keith Moore,1; accepted 7 December 2007; published 12 April 2008. [1] We use measurements of ocean surface dissolved Al (DEAD) model to constrain dust deposition to the oceans. Our Al database contains all available

  17. Modelling Al and Mn in the open ocean

    E-print Network

    Haak, Hein

    Modelling Al and Mn in the open ocean Marco van Hulten*, Alessandro Tagliabue, Jean-Claude Dutay van Hulten: Modelling Al and Mn in the open ocean 1 #12;Outline Introduction Model of aluminium Constraining dust flux Model of manganese Conclusions Marco van Hulten: Modelling Al and Mn in the open ocean 2

  18. 782 A. Y. KAPLAN ET AL. SOFIA U. TARASOVA

    E-print Network

    Kaplan, Alexander

    brain wave activities in real time and allow humans to use them for controlling any electronically addressable device or software through a local processor. In the late 1980s and early 1990s, the field of BCI deficit hyperactivity disorder in children (Linden et al., 1996; Lubar et al., 1997; Egner et al., 2001

  19. [Gerber et al (1989), Cancer 64, 2347-2353

    E-print Network

    Paris-Sud XI, Université de

    ;nisms of this effect remain to be elucidated. [Moon et al (1992) Cancer Detect Prev 16, 73-79; Fontana et al ( I 992) Cancer Res 50, 1977-1982]. In the present study, we exam- ine the effect of all[Gerber et al (1989), Cancer 64, 2347-2353

  20. Igor Kuznecov MOVPE von AlGaN-Schichten mit

    E-print Network

    Nabben, Reinhard

    moglich, die Emissionswellenlange einer LED von der Wellenlange des GaN (365nm) bis zur Wellenlange des Al Diplomarbeit ist das Wachstum von LED-Schichten mittels MOVPE. Dabei muss die Komposition des AlGaN und dieIgor Kuznecov MOVPE von AlGaN-Schichten mit hohem Aluminiumgehalt Es gibt zahlreiche

  1. Al2C monolayer: the planar tetracoordinate carbon global minimum

    NASA Astrophysics Data System (ADS)

    Li, Yafei; Liao, Yunlong; Schleyer, Paul Von Ragué; Chen, Zhongfang

    2014-08-01

    Inspired by our theoretical finding that C2Al62- has a planar D2h minimum with two planar tetracoordinate carbons (ptCs), we computationally designed a new two-dimensional (2D) inorganic material, an Al2C monolayer. All carbons in this monolayer are ptC's, stabilized inductively by binding to four electropositive Al atoms in the same plane. The Al2C monolayer is semiconducting with an indirect minimum band gap and a slightly larger direct band gap. Good persistence of the Al2C monolayer is indicated by its moderate cohesive energy, the absence of imaginary modes in its phonon spectrum, and the high melting point predicted by molecular dynamics (MD) simulations. Moreover, a particle-swarm optimization (PSO) global minimum search found the Al2C monolayer to be the lowest-energy 2D structure compared to other Al2C alternatives. Dividing the Al2C monolayer results in one-dimensional (1D) Al2C nanoribbons, which are computed to have quite rich characteristics such as direct or indirect band gaps with various values, depending on the direction of the division and the resulting edge configuration.Inspired by our theoretical finding that C2Al62- has a planar D2h minimum with two planar tetracoordinate carbons (ptCs), we computationally designed a new two-dimensional (2D) inorganic material, an Al2C monolayer. All carbons in this monolayer are ptC's, stabilized inductively by binding to four electropositive Al atoms in the same plane. The Al2C monolayer is semiconducting with an indirect minimum band gap and a slightly larger direct band gap. Good persistence of the Al2C monolayer is indicated by its moderate cohesive energy, the absence of imaginary modes in its phonon spectrum, and the high melting point predicted by molecular dynamics (MD) simulations. Moreover, a particle-swarm optimization (PSO) global minimum search found the Al2C monolayer to be the lowest-energy 2D structure compared to other Al2C alternatives. Dividing the Al2C monolayer results in one-dimensional (1D) Al2C nanoribbons, which are computed to have quite rich characteristics such as direct or indirect band gaps with various values, depending on the direction of the division and the resulting edge configuration. Electronic supplementary information (ESI) available: Complete citation of ref. 50, the band structure of an Al2C monolayer computed using the HSE06 functional, snapshots of MD simulations, and bulk structures of Al2C-II and Al2C-III. See DOI: 10.1039/c4nr01972e

  2. Effect of high intensity ultrasound on Al?Ni?, Al?Ni crystallite size in binary AlNi (50 wt% of Ni) alloy.

    PubMed

    Cherepanov, Pavel V; Melnyk, Inga; Andreeva, Daria V

    2015-03-01

    Crystallite size of the intermetallics is one of the most important parameters that can influence kinetics of catalytic reactions. Analysis of the crystallite sizes of Al?Ni and Al?Ni? intermetallic phases using Scherrer and Williamson-Hall methods reveals that the sonomechanical impact of ultrasound on suspensions of AlNi particles in ethanol results in crystallites growth and microstrain reduction. PMID:25171834

  3. Interdiffusion and intrinsic diffusion in the NiAl /delta/ phase of the Al-Ni system

    NASA Technical Reports Server (NTRS)

    Shankar, S.; Seigle, L. L.

    1978-01-01

    Interdiffusion coefficients at 950 to 1150 C and the ratio of intrinsic diffusion coefficients at 1100 C were measured as functions of composition in the NiAl (delta) phase of the Al-Ni system, using a vapor-solid technique. Diffusivity values were also obtained for the Ni3Al (epsilon) and Ni (Al) solid solution (zeta) phases from 950 to 1150 C. The interdiffusion coefficient in NiAl (delta) varies several orders of magnitude over the delta phase field with a deep minimum in the diffusivity-composition curve at 48 to 49 at% Al. The ratio of intrinsic diffusion coefficients DNi/DAl, in the delta phase also varies with composition from a value of 3 to 3.5 below 50 at% Al to 0.1 or less above 50 at% Al.

  4. Ab initio molecular dynamics of Al irradiation-induced processes during Al{sub 2}O{sub 3} growth

    SciTech Connect

    Music, Denis; Nahif, Farwah; Friederichsen, Niklas; Schneider, Jochen M. [Materials Chemistry, RWTH Aachen University, D-52056 Aachen (Germany); Sarakinos, Kostas [Plasma and Coatings Physics Division, Linkoeping University, SE-58183 Linkoeping (Sweden)

    2011-03-14

    Al bombardment induced structural changes in {alpha}-Al{sub 2}O{sub 3} (R-3c) and {gamma}-Al{sub 2}O{sub 3} (Fd-3m) were studied using ab initio molecular dynamics. Diffusion and irradiation damage occur for both polymorphs in the kinetic energy range from 3.5 to 40 eV. However, for {gamma}-Al{sub 2}O{sub 3}(001) subplantation of impinging Al causes significantly larger irradiation damage and hence larger mobility as compared to {alpha}-Al{sub 2}O{sub 3}. Consequently, fast diffusion along {gamma}-Al{sub 2}O{sub 3}(001) gives rise to preferential {alpha}-Al{sub 2}O{sub 3}(0001) growth, which is consistent with published structure evolution experiments.

  5. Investigation of the low-temperature AlGaN interlayer in AlGaN/GaN/AlGaN double heterostructure on Si substrate

    NASA Astrophysics Data System (ADS)

    Hsiao, Yu-Lin; Wang, Yi-Jie; Chang, Chia-Ao; Weng, You-Chen; Chen, Yen-Yu; Chen, Kai-Wei; Maa, Jer-Shen; Chang, Edward Yi

    2014-11-01

    A low-temperature (LT) AlGaN interlayer is inserted in the Al0.1Ga0.9N back barrier layer of an Al0.2Ga0.8N/GaN/Al0.1Ga0.9N double heterostructure grown on a 150 mm Si substrate. It is found that the 21-nm-thick LT-AlGaN interlayer plays an important role in stress relaxation and dislocation reduction of the Al0.1Ga0.9N back barrier layer, especially for screw dislocation reduction. In addition, a buffer breakdown voltage higher than 600 V is achieved, which is much higher than those of conventional heterostructures. These results demonstrate the effectiveness of combining the LT-AlGaN interlayer and the Al0.2Ga0.8N/GaN/Al0.1Ga0.9N double heterostructure on a Si substrate to increase the breakdown voltage for high-power applications.

  6. Properties of NiAl and Ni-Al-N thin films deposited by closed field unbalanced magnetron sputter ion plating using elemental Ni and Al targets.

    PubMed

    Baig, M N; Ahmed, W; Khalid, F A; Said, R M; McLaughlin, J

    2009-07-01

    Approximately 1 microm thick NiAl and Ni-Al-N thin films have been deposited from individual elemental Ni (99.5% pure) and Al (99.5% pure) targets onto glass and stainless steel 316 substrates using closed field unbalanced magnetron sputter ion platting (CFUBMSIP) process. The films have been characterized using stylus profilometry, energy dispersive spectroscopy (EDAX), X-ray diffractometry (XRD) and atomic force microscopy (AFM). The X-ray diffraction patterns of both types of thin films produced confirmed the formation of beta-NiAl phase. The EDAX results revealed that all of the NiAl thin films produced exhibited the near equiatomic NiAl phase with the best results given by the one deposited using 300 Watts DC power for Ni and 400 Watts DC power for Al targets respectively. However, the Ni-Al-N thin films showed a Ni-rich NiAl phase. AFM results of both types of films produced carried out on glass samples exhibited that the coatings have quite a smooth surface with surface roughness in nanometres range. PMID:19916405

  7. AlGaN/GaN MIS-HEMT Gate Structure Improvement Using Al2O3 Deposited by PEALD

    E-print Network

    Boyer, Edmond

    AlGaN/GaN MIS-HEMT Gate Structure Improvement Using Al2O3 Deposited by PEALD R. Meunier1 , A, 38054 Grenoble Cedex 9, France 2 LAAS-CNRS, 7 Avenue du Colonel Roche, 31400 Toulouse, France AlGaN /GaN behavior. Those trapped charges can be associated to the carbon contamination of the AlGaN surface

  8. Formation of nanocrystalline B2 NiAl through cryomilling of Ni50 at.%Al at 87 K

    Microsoft Academic Search

    B.-L. Huang; J. Vallone; M. J. Luton

    1995-01-01

    A wear-like mechanism occurs between balls and the entrapped nanocrystalline mixture of elemental Ni and Al powders resulting in the formation of B2 NiAl at the process temperature at 87 K during cryomilling. Nanocrystalline structure of B2 NiAl with average size of 6 nm was synthesized after 45 hours of milling. This B2 NiAl was found to be at nonstoichiometric

  9. Adhesion, Atomic Structure, and Bonding at the Al2O3(0001)/Al(111) Interface: A First Principles Study

    E-print Network

    Adams, James B

    Adhesion, Atomic Structure, and Bonding at the «­Al2O3(0001)/Al(111) Interface: A First Principles ), and bond character of the «­Al2O3(0001)/Al(111) interface. A total of six candidate interface structures, and have determined that a major contribution to bonding across the interface is simi- lar to what is found

  10. Isolation and characterization of a rice mutant hypersensitive to Al.

    PubMed

    Ma, Jian Feng; Nagao, Sakiko; Huang, Chao Feng; Nishimura, Minoru

    2005-07-01

    Rice (Oryza sativa L.) is a highly Al-resistant species among small grain crops, but the mechanism responsible for the high Al resistance has not been elucidated. In this study, rice mutants sensitive to Al were isolated from M(3) lines derived from an Al-resistant cultivar, Koshihikari, irradiated with gamma-rays. Relative root elongation was used as a parameter for evaluating Al resistance. After initial screening plus two rounds of confirmatory testing, a mutant (als1) was isolated from a total of 560 lines. This mutant showed a phenotype similar to the wild-type plant in the absence of Al. However, in the presence of 10 microM Al, root elongation was inhibited 70% in the mutant, but only 8% in the wild-type plant. The mutant also showed poorer root growth in acid soil. The Al content of root apices (0-1 cm) was much lower in the wild-type plant. The sensitivity to other metals including Cd and La did not differ between the mutant and the wild-type plants. A small amount of citrate was secreted from the roots of the mutant in response to Al stress, but there was no difference from that secreted by the wild-type plant. Genetic analysis of F(2) populations between als1 and wild-type plants showed that the Al-resistant seedlings and Al-sensitive seedlings segregated at a 3 : 1 ratio, indicating that the high sensitivity to Al in als1 is controlled by a single recessive gene. The gene was mapped to the long arm of chromosome 6, flanked by InDel markers MaOs0619 and MaOs0615. PMID:15857838

  11. Metallurgical Characteristics of TiAlN/AlCrN Coating Synthesized by the PVD Process on a Cutting Insert

    NASA Astrophysics Data System (ADS)

    Sampath Kumar, T.; Balasivanandha Prabu, S.; Manivasagam, Geetha

    2014-08-01

    TiAlN/AlCrN coating was deposited on a tungsten carbide insert, using the plasma-enhanced physical vapor deposition (PEPVD) process. The microstructure of the coating was examined and it was found that the TiAlN/AlCrN coating was uniform, highly dense, and less porous. The different phases formed in the coating were analyzed using the x-ray diffraction. The hardness and scratch resistance were measured using the nanoindentation tester and scratch tester, respectively. TiAlN/AlCrN exhibited higher hardness, higher Young's modulus, and superior scratch resistance when compared to the conventional coatings, such as TiAlN, AlCrN, and TiN. The surface morphology of the coating was characterized using the atomic force microscope (AFM). The surface roughness was found to be lesser in the TiAlN/AlCrN coating. The TiAlN/AlCrN coating has proved to have better corrosion resistance, compared to the uncoated carbide substrate.

  12. Growth of crack-free AlGaN film on thin AlN interlayer by MOCVD

    NASA Astrophysics Data System (ADS)

    Jin, R. Q.; Liu, J. P.; Zhang, J. C.; Yang, H.

    2004-07-01

    We have studied the effect of low-temperature-deposited (LT) and high-temperature-deposited (HT) AlN interlayer with various thickness on AlGaN film grown on GaN using c-plane sapphire as substrate. All the Al 0.25Ga 0.75N films thicker than 1 ?m with LT-AlN interlayer or with HT-AlN interlayer were free of cracks, however, their surfaces were different: the Al 0.25Ga 0.75N films with LT-AlN interlayer showed smooth surface, while those with HT-AlN interlayer exhibit rough surface morphology. The results of X-ray double crystal diffraction and Rutherford backscattering showed that all of the AlGaN films were under compressive strain in the parallel direction. The compressive strain resulted from the effect of interlayer-induced stress relieving and the thermal mismatch for the samples with LT-AlN interlayer, and it was due to the thermal mismatch between AlGaN and the underlying layers for those with HT-AlN interlayer.

  13. Oficina de Cooperacin al Desarrollo y Solidaridad (OCDS) La Oficina de Cooperacin al Desarrollo y Solidaridad (OCDS) se consolida, despus

    E-print Network

    Oro, Daniel

    Oficina de Cooperación al Desarrollo y Solidaridad (OCDS) La Oficina de Cooperación al Desarrollo y Solidaridad (OCDS) se consolida, después de su creación en mayo de 2005 por acuerdo ejecutivo del Consejo de hacia la cooperación universitaria al desarrollo (CUD), la tarea hecha por el equipo de la OCDS y la

  14. Cryptanalysis of Cho et al.'s Protocol, A Hash-Based Mutual Authentication Protocol for RFID Systems

    E-print Network

    Cryptanalysis of Cho et al.'s Protocol, A Hash-Based Mutual Authentication Protocol for RFID cryptanalysis a hash based RFID mutual authentication protocol which has been recently proposed by Cho et al impersonation attack: the success probability of attack is "1 4 " for two runs of protocol. Keywords: RFID

  15. MnAl and MnAlC permanent magnets produced by mechanical alloying

    SciTech Connect

    Crew, D.C.; McCormick, P.G.; Street, R. [Univ. of Western Australia, Nedlands (Australia). Research Centre for Advanced Mineral and Materials Processing] [Univ. of Western Australia, Nedlands (Australia). Research Centre for Advanced Mineral and Materials Processing

    1995-02-01

    The ferromagnetic {tau} phase in the MnAl system, first reported by Kono and Koch et al., has the potential to replace anisotropic ferrites as a permanent magnet material. The {tau} phase is metastable and is usually produced by a rapid quench of the high temperature {var_epsilon} phase followed by isothermal annealing at temperatures between 400 and 700 C. Prolonged annealing results in decomposition of the {tau} phase to the equilibrium {gamma} and {beta}-Mn phases. The addition of carbon to the alloy stabilizes the {tau} phase against decomposition and improves both the magnetic properties and ductility. Mechanical alloying has been used successfully to synthesize a number of rare earth permanent magnet alloys, including Nd{sub 2}Fe{sub 14}B and SmCo{sub 5}. This processing technique can be used to produce a nanocrystalline microstructure, with a grain size below 10 nm, similar to some rapidly quenched structures. This small grain size can have beneficial effects upon the magnetic properties. The mechanical alloying of manganese and aluminum with compositions near 34 wt% Mn has been previously reported, however, no work appears to have been carried out in the region of the {tau} phase near 70 wt% Mn. In this paper the authors report the results of a study of the structure and magnetic properties of MnAl and MnAlC prepared by mechanical alloying and heat treatment.

  16. Aesthetic Leadership (AL): Development and Implementation of Aesthetic Leadership Scale (ALS) of the School Directors

    ERIC Educational Resources Information Center

    Polat, Soner; Oztoprak-Kavak, Zehra

    2011-01-01

    This study aims to develop a scale for measuring the aesthetic leadership (AL) characteristics of the school directors and to show that it can be applicable. The population of the study is composed of the teachers who are on duty in the elementary, secondary and high schools located in Izmit, Kocaeli. Sample of this descriptive study comprises 400…

  17. Wetting of Cu and Al by Sn-Zn and Zn-Al Eutectic Alloys

    NASA Astrophysics Data System (ADS)

    Pstru?, Janusz; Fima, Przemys?aw; Gancarz, Tomasz

    2012-05-01

    Wetting properties of Sn-Zn and Zn-Al alloys on Cu and Al substrates were studied. Spreading tests were carried out for 3 min, in air and under protective atmosphere of nitrogen, with the use of fluxes. In the case of Zn-Al eutectic, spreading tests were carried out at 460, 480, 500, and 520 °C, and in the case of Sn-Zn eutectic at 250, 300, 350, 400, 450, and 500 °C, respectively. Solidified solder/substrate couples were cross-sectioned and subjected to microstructure examination. The spreading tests indicated that the wetting properties of eutectic Sn-Zn alloys, on copper pads do not depend on temperature (up to 400 °C), but in the lack of protective atmosphere, the solder does not wet the pads. Wettability studies of Zn-Al eutectic on aluminum and copper substrates have shown a negative effect of the protective nitrogen atmosphere on the wetting properties, especially for the copper pads. Furthermore, it was noted that with increasing temperature the solder wettability is improved. In addition, densities of liquid solders were studied by means of dilatometric technique.

  18. High Temperature Mechanical Characterization and Analysis of Al2O3 /Al2O3 Composition

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Jaskowiak, Martha H.

    1999-01-01

    Sixteen ply unidirectional zirconia coated single crystal Al2O3 fiber reinforced polycrystalline Al2O3 was tested in uniaxial tension at temperatures to 1400 C in air. Fiber volume fractions ranged from 26 to 31%. The matrix has primarily open porosity of approximately 40%. Theories for predicting the Young's modulus, first matrix cracking stress, and ultimate strength were applied and evaluated for suitability in predicting the mechanical behavior of Al2O3/Al2O3 composites. The composite exhibited pseudo tough behavior (increased area under the stress/strain curve relative to monolithic alumina) from 22 to 1400 C. The rule-of-mixtures provides a good estimate of the Young's modulus of the composite using the constituent properties from room temperature to approximately 1200 C for short term static tensile tests in air. The ACK theory provides the best approximation of the first matrix cracking stress while accounting for residual stresses at room temperature. Difficulties in determining the fiber/matrix interfacial shear stress at high temperatures prevented the accurate prediction of the first matrix cracking stress above room temperature. The theory of Cao and Thouless, based on Weibull statistics, gave the best prediction for the composite ultimate tensile strength.

  19. Magnetic domain structure and anisotropy distribution in Al/Metglas 2605S2/Al trilayers

    NASA Astrophysics Data System (ADS)

    Moscon, P. S.; Sánchez, F. H.; Passamani, E. C.; Larica, C.; Mendoza Zélis, P.

    2008-11-01

    Al coatings, with thickness (x) up to 20 µm, were deposited by dc sputtering on both sides of the Metglas 2605S2 precursor melt-spun ribbons. Spin reorientation, induced by the magnetoelastic effect, was clearly observed in the Al/Metglas 2605S2/Al trilayers by monitoring the 2 and 5 line intensities of the Mössbauer spectra obtained at different temperatures. The average spin orientation angles can be controlled by adjusting the Al thickness. A magneto-mechanical coefficient, which measures the rate of spin reorientation with respect to the temperature variation, was obtained and is found to be equal to -0.15° K-1 and -0.28° K-1 for x = 5 µm and 20 µm, respectively. Using a spin structure phenomenological model, in-plane native magnetic anisotropies ranging up to 3 kJ m-3 were estimated for the Metglas 2605S2 ribbons. Energy anisotropy values higher than 20 kJ m-3 are associated with inhomogeneities and defects from the sample preparation method and may correspond to about 10% of the ribbon volume.

  20. High reflectivity ultraviolet distributed Bragg reflector based on AlGaN/AlGaN multilayer

    NASA Astrophysics Data System (ADS)

    Shimada, Ryoko; Xie, Jinqiao; Morkoç, Hadis

    2007-02-01

    AlGaN/AlGaN distributed Bragg reflectors (DBRs) designed for the ultraviolet spectral region have been attained. The crack-free structures were grown on c-plane sapphire by plasma assisted molecular beam epitaxy (MBE). To minimize the built-in strain in DBRs, a thin buffer layer was used directly on c-plane sapphire. A peak reflectivity of 95% at 381 nm with a 21 nm stop band width was obtained at room temperature (RT) using a 32.5 pairs Al 0.7Ga 0.3N/Al 0.15Ga 0.85N DBR. With a driving force for DBRs and emitting regions in wide band gap semiconductor microcavities, such as those based on GaN and ZnO, is the quest for cavity polariton which is the coupled mode between the exciton and photon modes. Moreover, the exploitation of cavity polaritons could be expected in the course of the development of extremely low-threshold optoelectronics devices.

  1. ESTUDIO DE LA RESISTENCIA AL DESGASTE DE RECUBRIMIENTOS DEPOSITADOS MEDIANTE PROYECCIÓN TÉRMICA SOBRE ACERO AL CARBONO

    Microsoft Academic Search

    SERGIO ECHEVERRI; Estudiante Ingeniería; JULIANA BEDOYA; Estudiante Ingeniería de Materiales; FABIO VARGAS; Ingeniero Metalúrgico

    2007-01-01

    Coatings of Ni - Al, Ni - SiC, Ni -WC y Ni - W- Co, were deposited and its capacity to protect of the abrasive wear effects on the steel substrate where they were deposited was studied. Coatings were obtained by thermal spraying using oxygen - acetylene combustion gotten by an Eutalloy torch of the Eutectic Castolin trade mark. Materials

  2. Structural, Optical, and Electrical Characterization of Al/ n-ZnO/ p-Si/Al Heterostructures

    NASA Astrophysics Data System (ADS)

    Kumar, Rajender; Chand, Subhash

    2015-01-01

    For heterojunction fabrication, zinc oxide thin films were grown on p-Si by pulsed laser deposition. X-ray diffraction patterns were used to study the grain size and morphology of the films. The optical properties of the films were studied by UV-visible and photoluminescence spectroscopy. Experimental observations confirmed that the deposited films have potential for sharp emission in the visible region. High-purity (99.999%) vacuum evaporated aluminium metal was used to make contacts to the n-ZnO and p-Si. The current-voltage characteristics of the Al/ n-ZnO/ p-Si(100)/Al heterostructure measured over the temperature range 60-300 K were studied on the basis of the thermionic emission diffusion mechanism. The equivalent Schottky barrier height and the diode ideality factor were determined by fitting measured current-voltage data to the thermionic emission diffusion equation. It was observed that the barrier height decreased and the ideality factor increased with decreasing temperature, and that the activation energy plot was non-linear at low temperature. These characteristics are attributed to the Gaussian distribution of barrier heights. The capacitance-voltage characteristics of the Al/ n-ZnO/ p-Si(100)/Al heterostructure diode were studied over a wide temperature range. The impurity concentration in deposited n-type ZnO films was estimated from measured capacitance-voltage data.

  3. X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu

    NASA Astrophysics Data System (ADS)

    Mathiesen, R. H.; Arnberg, L.; Li, Y.; Meier, V.; Schaffer, P. L.; Snigireva, I.; Snigirev, A.; Dahle, A. K.

    2011-01-01

    Al-Si eutectic growth has been studied in-situ for the first time using X-ray video microscopy during directional solidification (DS) in unmodified and Sr-modified Al-Si-Cu alloys. In the unmodified alloys, Si is found to grow predominantly with needle-like tip morphologies, leading a highly irregular progressing eutectic interface with subsequent nucleation and growth of Al from the Si surfaces. In the Sr-modified alloys, the eutectic reaction is strongly suppressed, occurring with low nucleation frequency at undercoolings in the range 10 K to 18 K. In order to transport Cu rejected at the eutectic front back into the melt, the modified eutectic colonies attain meso-scale interface perturbations that eventually evolve into equiaxed composite-structure cells. The eutectic front also attains short-range microscale interface perturbations consistent with the characteristics of a fibrous Si growth. Evidence was found in support of Si nucleation occurring on potent particles suspended in the melt. Yet, both with Sr-modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form at the Si-particle interfaces.

  4. First-principles calculations of Al dimer dynamics on Al(111)

    NASA Astrophysics Data System (ADS)

    Bogicevic, Alexander; Hyldgaard, Per; Lundqvist, Bengt I.

    1998-03-01

    We study the dynamics of Al dimers on Al(111) using first-principles density-functional (DFT) calculations. The smooth potential energy surface ensures very low activation barriers for dimer rotation (<0.03 eV). This non-diffusive motion is confined by larger activation barriers for migration by concerted sliding (0.13 eV) and so-called inter-cell rotation (0.50 eV). The ground state is unexpectedly mixed, with the dimer atoms in neighboring fcc and hcp sites, and is enabled by a significant surface relaxation. A compressive strain (<= 5 %) effectively eliminates the already low rotation barriers, and establishes a new ground state consisting of a double bridge occupancy. The fcc-fcc and hcp-hcp configurations are rendered unstable, which has implications on the diffusive sliding motion. These effects lead us to discuss the possibility of a metal quantum rotor. The Al_2/Al(111) quantum rotor is in the end ruled out due to a strong coupling to the substrate, dominated by rather large elastic energies associated with the oscillations of certain underlying surface atoms. The many-body dissipation effects at various degrees of compression are studied with the effective-medium theory. Finally, dissociation of the dimer is shown to require as much as a 100% bond stretch.

  5. Dynamic recrystallization in Al–Mg–Sc alloys

    Microsoft Academic Search

    Kentaro Ihara; Yasuhiro Miura

    2004-01-01

    The main research interest was to investigate the mechanisms in the restoration process of Al–3mass% Mg and Al–3mass% Mg–0.2mass% Sc alloy containing second-phase Al3Sc precipitates. The alloy specimen, Al–3% Mg–0.2% Sc, was peak-aged, where it contained stable coherent, spherical Al3Sc precipitates with an average diameter of 0.2?m and a volume fraction of 0.005. The main techniques utilized are compression tests,

  6. A novel hydride phase in hydrogen charged Ti3Al

    NASA Technical Reports Server (NTRS)

    Schwartz, D. S.; Lederich, R. J.; Sastry, S. M. L.; Yelon, W. B.; Berliner, R. R.

    1991-01-01

    The effect of internal hydrogen on the microstructural modification of Ti3Al (alpha-2) compound was studied by large-angle neutron scattering and TEM. Ti-25 at. pct Al (Ti3Al) specimens were exposed to gaseous hydrogen atmosphere at 600 C that resulted in internal hydrogen concentration of 2000 ppm. The hydrogen-charged alloy consisted of a mixture of alpha-2 phase and a novel Ti3AlH phase with the E2(1), (Pm3m) crystal structure. The lattice parameters and atomic arrangement of the Ti3AlH phase were determined.

  7. Ultraviolet laser diodes on sapphire and AlN substrates

    NASA Astrophysics Data System (ADS)

    Kneissl, Michael; Yang, Zhihong; Teepe, Mark; Johnson, Noble M.

    2009-02-01

    The performance characteristics of InAlGaN multiple quantum well (MQW) lasers grown on sapphire and low defect density bulk AlN substrates has been compared. The group III-nitride laser heterostructures were grown on (0001) AlN and c-plane sapphire substrates by metalorganic vapor phase epitaxy (MOVPE). Lasing was observed for optically pumped AlGaInN heterostructures in the wavelength range between 333 nm and 310 nm. A comparison of laser thresholds shows reduced threshold power densities for lasers grown on bulk AlN with threshold densities as low as 175 kW/cm2 for lasers emitting near 330 nm.

  8. Crystal structure of novel compounds in the systems Zr-Cu-Al, Mo-Pd-Al and partial phase equilibria in the Mo-Pd-Al system.

    PubMed

    Khan, Atta U; Rogl, P; Giester, G

    2012-02-28

    The crystal structures of three Al-rich compounds have been solved from X-ray single crystal diffractometry: ?(1)-MoPd(2-x)Al(8+x) (x = 0.067); ?(7)-Zr(Cu(1-x)Al(x))(12) (x = 0.514) and ?(9)-ZrCu(1-x)Al(4) (x = 0.144). ?(1)-MoPd(2-x)Al(8+x) adopts a unique structure type (space group Pbcm; lattice parameters a = 0.78153(2), b = 1.02643(3) and c = 0.86098(2) nm), which can be conceived as a superstructure of the Mo(Cu(x)Al(1-x))(6)Al(4) type. Whereas Mo-atoms occupy the 4d site, Pd(2) occupies the 4c site, Al and Pd(1) atoms randomly share the 4d position and the rest of the positions are fully occupied by Al. A Bärnighausen tree documents the crystallographic group-subgroup relation between the structure types of Mo(Cu(x)Al(1-x))(6)Al(4) and ?(1). ?(7)-Zr(Cu(1-x)Al(x))(12) (x = 0.514) has been confirmed to crystallize with the ThMn(12) type (space group I4/mmm; lattice parameters a = 0.85243(2) and c = 0.50862(3) nm). In total, 4 crystallographic sites were defined, out of which, Zr occupies site 2a, the 8f site is fully occupied by Cu, the 8i site is entirely occupied by Al, but the 8j site turned out to comprise a random mixture of Cu and Al atoms. The compound ?(9)-ZrCu(1-x)Al(4) (x = 0.144) crystallizes in a unique structure type (space group P4/nmm; lattice parameters a = 0.40275(3) and c = 1.17688(4) nm) which exhibits full atom order but a vacancy (14.4%) on the 2c site, shared with Cu atoms. ?(9)-ZrCu(1-x)Al(4) is a superstructure of Cu with an arrangement of three unit cells of Cu in the direction of the c-axis. A Bärnighausen tree documents this relationship. The ZrCu(1-x)Al(4) type (n = 3) is part of a series of structures which follow this building principle: Cu (n = 1), TiAl(3) (n = 2), ?(5)-TiNi(2-x)Al(5) (n = 4), HfGa(2) (n = 6) and Cu(3)Pd (n = 7). A partial isothermal section for the Al-rich part of the Mo-Pd-Al system at 860 °C has been established with two ternary compounds ?(1)-MoPd(2-x)Al(8+x) and ?(2) (unknown structure). The Vickers hardness (H(v)) for ?(1) was found to be 842 ± 40 MPa. PMID:22183686

  9. Electron-ion recombination rate coefficients and photoionization cross-sections for Al XI, Al XII, Si XII, Si XIII for UV and X-ray modeling

    E-print Network

    Nahar, Sultana Nurun

    Electron-ion recombination rate coefficients and photoionization cross-sections for Al XI, Al XII-ion recombination UV and X-rays Al XI, Al XII, Si XII, Si XIII a b s t r a c t Results are presented from detailed study of inverse processes of photoionization and electron-ion recombination of (hm + Al XI Al XII + e

  10. Is the Frontal Assessment Battery reliable in ALS patients?

    PubMed

    Raaphorst, Joost; Beeldman, Emma; Jaeger, Bregje; Schmand, Ben; van den Berg, Leonard H; Weikamp, Janneke G; Schelhaas, H Jurgen; de Visser, Marianne; de Haan, Rob J

    2013-01-01

    The assessment of frontal functions in ALS patients is important because of the overlap with the behavioural variant of frontotemporal dementia (bvFTD). We investigated the applicability and reliability of the Frontal Assessment Battery (FAB) within a cohort of predominantly prevalent ALS patients. The FAB was administered to 85 ALS patients and eight ALS-bvFTD patients. Original scores and the percentage of items that could be performed were recorded. Item-adjusted scores of the FAB were calculated. The ALS Functional Rating Scale-Revised version (ALSFRS-R) was used to assess disease severity. Eighty-seven patients (94%) had ALS symptoms of more than one year. Twenty patients (21.5%) were not able to perform one or more FAB items. The original FAB score correlated with the ALSFRS-R score (r = 0.30; p < 0.01), while the item-adjusted FAB score did not. In contrast to the original FAB scores, the item-adjusted FAB score was lower in ALS-bvFTD patients (66.7, range 33.3-100) compared to ALS patients without bvFTD (94.4, range 38.9-100; p < 0.01). In summary, 20% of prevalent ALS patients could not complete the FAB, which limits its use in ALS and emphasizes the importance of disease specific instruments and adjusting for motor impairment in cognitive and behavioural examinations of ALS patients. PMID:22889176

  11. Low alpha experiments at the ALS

    SciTech Connect

    Robin, D.; Alvis, R.; Jackson, A. [Lawrence Berkeley Lab., CA (United States); Holtzapple, R.; Podobedov, B. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1995-08-01

    The authors present a modified, low alpha lattice for the Advanced Light Source where the quadrupole field strengths have been detuned to allow the momentum compaction factor to be varied smoothly from positive to negative values. With this low alpha lattice the authors decrease the momentum compaction factor by a factor of 5 to 0.0003 over normal operation resulting in a measured bunch length reduction of 2. They also measure the size the second order momentum compaction factor as well as store beam in a negative momentum compaction lattice. Streak camera measurements at positive and negative momentum compaction operation show longitudinal beam profile distributions that are in agreement with simulations by Fang et al.

  12. Tribological properties of thermally sprayed TiAl-Al2O3 composite coating

    NASA Astrophysics Data System (ADS)

    Salman, A.; Gabbitas, B.; Li, J.; Zhang, D.

    2009-08-01

    The use of thermal spray coatings provides protection to the surfaces operating in severe environments. The main goal of the current work is to investigate the possibility of using a high velocity oxy fuel (HVOF) thermally sprayed wear resistant TiAl/Al2O3 coating on tool steel (H13) which is used for making dies for aluminium high pressure die casting. A feedstock of TiAl/Al2O3 composite powder was produced from a mixture of Al and TiO2 powders by high energy mechanical milling, followed by a thermal reaction process. The feedstock was then thermally sprayed using a high velocity oxy-fuel (HVOF) technique onto H13 steel substrates to produce a composite coating. The present study describes and compares the tribological properties such as friction and sliding wear rate of the coating both at room and high temperature (700°C). The results showed that the composite coating has lower wear rate at high temperature (700°C) than the uncoated H13 sample. At Room temperature without using lubricant there is no much significant difference between the wear rate of the coated and uncoated samples. The experimental results showed that the composite coating has great potential for high temperature application due to its lower wear rate at high temperature in comparison with the uncoated sample at the same temperature. The composite coating was characterized using scanning electron microscopy (SEM), optical microscopy and X-ray diffractometry (XRD). This paper reports the experimental observations and discusses the wear resistance performance of the coatings at room and high temperatures.

  13. 26Al uptake and accumulation in the rat brain

    NASA Astrophysics Data System (ADS)

    Yumoto, S.; Nagai, H.; Imamura, M.; Matsuzaki, H.; Hayashi, K.; Masuda, A.; Kumazawa, H.; Ohashi, H.; Kobayashi, K.

    1997-03-01

    To investigate the cause of Alzheimer's disease (senile dementia), 26Al incorporation in the rat brain was studied by accelerator mass spectrometry (AMS). When 26Al was injected into healthy rats, a considerable amount of 26Al entered the brain (cerebrum) through the blood-brain barrier 5 days after a single injection, and the brain 26Al level remained almost constant from 5 to 270 days. On the other hand, the level of 26Al in the blood decreased remarkably 75 days after injection. Approximately 89% of the 26Al taken in by the brain cell nuclei bound to chromatin. This study supports the theory that Alzheimer's disease is caused by irreversible accumulation of aluminium (Al) in the brain, and brain cell nuclei.

  14. Overview of the development of FeAl intermetallic alloys

    SciTech Connect

    Maziasz, P.J.; Liu, C.T.; Goodwin, G.M.

    1995-09-01

    B2-phase FeAl ordered intermetallic alloys based on an Fe-36 at.% Al composition are being developed to optimize a combination of properties that includes high-temperature strength, room-temperature ductility, and weldability. Microalloying with boron and proper processing are very important for FeAl properties optimization. These alloys also have the good to outstanding resistance to oxidation, sulfidation, and corrosion in molten salts or chlorides at elevated temperatures, characteristic of FeAl with 30--40 at.% Al. Ingot- and powder-metallurgy (IM and PM, respectively) processing both produce good properties, including strength above 400 MPa up to about 750 C. Technology development to produce FeAl components for industry testing is in progress. In parallel, weld-overlay cladding and powder coating technologies are also being developed to take immediate advantage of the high-temperature corrosion/oxidation and erosion/wear resistance of FeAl.

  15. Targeting autophagy in ALS: a complex mission.

    PubMed

    Nassif, Melissa; Hetz, Claudio

    2011-04-01

    Several neurodegenerative diseases share a common neuropathology, primarily featuring the presence of abnormal protein inclusions in the brain containing specific misfolded proteins. Strategies to decrease the load of protein aggregates and oligomers are considered relevant targets for therapeutic intervention. Many studies indicate that macroautophagy is a selective and efficient mechanism for the degradation of misfolded mutant proteins related to neurodegeneration, without affecting the levels of the corresponding wild-type form. In fact, activation of autophagy by rapamycin treatment decreases the accumulation of protein aggregates and alleviates disease features in animal models of Huntington disease and other disorders affecting the nervous system. Recent evidence, however, indicates that the expression of several disease-related genes may actually impair autophagy activity at different levels, including omegasome formation, substrate recognition, lysosomal acidity and autophagosome membrane nucleation. A recent report from Zhang and co-workers indicates that treatment of an amyotrophic lateral sclerosis (ALS) mouse model with rapamycin actually exacerbates neuronal loss and disease progression, associated with enhanced apoptosis. This study reflects the need for a better understanding of the contribution of autophagy to ALS and other neurodegenerative diseases since this pathway may not only operate as a cleaning-up mechanism. Then, autophagy impairment may be part of the pathological mechanisms underlying the disease, whereas augmenting autophagy levels above a certain threshold could lead to detrimental effects in neuronal function and survival. Combinatorial strategies to repair the autophagy deficit and also enhance the activation of the pathway may result in a beneficial impact to decrease the content of protein aggregates and damaged organelles, improving neuronal function and survival. PMID:21252621

  16. Comparison of the transport properties of high quality AlGaN/AlN/GaN and AlInN/AlN/GaN two-dimensional electron gas heterostructures

    NASA Astrophysics Data System (ADS)

    Tülek, Remziye; Ilgaz, Aykut; Gökden, Sibel; Teke, Ali; Öztürk, Mustafa K.; Kasap, Mehmet; Özçelik, Süleyman; Arslan, Engin; Özbay, Ekmel

    2009-01-01

    The transport properties of high mobility AlGaN/AlN/GaN and high sheet electron density AlInN/AlN/GaN two-dimensional electron gas (2DEG) heterostructures were studied. The samples were grown by metal-organic chemical vapor deposition on c-plane sapphire substrates. The room temperature electron mobility was measured as 1700 cm2/V s along with 8.44×1012 cm-2 electron density, which resulted in a two-dimensional sheet resistance of 435 ?/? for the Al0.2Ga0.8N/AlN/GaN heterostructure. The sample designed with an Al0.88In0.12N barrier exhibited very high sheet electron density of 4.23×1013 cm-2 with a corresponding electron mobility of 812 cm2/V s at room temperature. A record two-dimensional sheet resistance of 182 ?/? was obtained in the respective sample. In order to understand the observed transport properties, various scattering mechanisms such as acoustic and optical phonons, interface roughness, and alloy disordering were included in the theoretical model that was applied to the temperature dependent mobility data. It was found that the interface roughness scattering in turn reduces the room temperature mobility of the Al0.88In0.12N/AlN/GaN heterostructure. The observed high 2DEG density was attributed to the larger polarization fields that exist in the sample with an Al0.88In0.12N barrier layer. From these analyses, it can be argued that the AlInN/AlN/GaN high electron mobility transistors (HEMTs), after further optimization of the growth and design parameters, could show better transistor performance compared to AlGaN/AlN/GaN based HEMTs.

  17. Tropical soils cultivated with tomato: fractionation and speciation of Al.

    PubMed

    Nogueirol, Roberta Corrêa; Monteiro, Francisco Antonio; Azevedo, Ricardo Antunes

    2015-04-01

    Soil acidity and the associated problems of aluminum (Al) toxicity and scarce exchangeable bases are typically the most important limiting factors of agricultural yield in wet tropical regions. The goals of this study were to test how soil lime rates affect the forms and distribution of Al in the soil fractions and how different levels of bioavailable Al affect two tomato genotypes grown in wet tropical soils. The tomato genotypes CNPH 0082 and Calabash Rouge were grown in two wet tropical soils in a greenhouse. Soil lime rates of 0, 560, and 2240 mg kg(-1) soil (clay soil) and 0, 280, and 1120 mg kg(-1) soil (sandy soil) were applied to modify Al concentrations. Dry mass production and Al concentrations were determined in shoots and roots. Al was fractionated in the soil, and the soil solution was speciated after cultivation. The Calabash Rouge genotype possesses mechanisms to tolerate Al(3+), absorbed less Al, exhibited smaller reduction in growth, and lower Al concentrations in plant parts than the CNPH 0082. Increased soil pH reduced the exchangeable Al fraction and increased the fraction mainly linked to organic matter. Al in the soil in the form of complexes with organic compounds and Al(SO4)(+) (at the highest lime rate) did not affect plant development. Soil acidity can be easily neutralized by liming the soil, which transforms toxic Al(3+) in the soil into forms that do not harm tomato plants, thereby avoiding oxidative stress in the plants. Al-induced stress in tomatoes varies with genotypes and soil type. PMID:25740686

  18. Electronic Structures of CeNi 2Al 5 and CeNiAl 4 Studied by Photoelectron Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kashiwakura, Takayuki; Okane, Tetsuo; Suzuki, Shoji; Sato, Shigeru; Watanabe, Masamitsu; Harasawa, Ayumi; Kinoshita, Toyohiko; Kakizaki, Akito; Ishii, Takehiko; Nakai, Shun-ichi; Isikawa, Yosikazu

    2000-09-01

    We have studied the electronic structures of ternary intermetallic compounds CeNi2Al5 and CeNiAl4 on the basis of Ce 3d core level spectra by X-ray photoelectron spectroscopy and high resolution Ce 4d?4f resonant photoemission spectra. In the 4f photoemission spectra, fine structures near the Fermi edge manifest that hybridization strength is considerably larger in CeNiAl4 than in CeNi2Al5. The electronic structures of these compounds are discussed in connection with those of Ce Ni and Ce Al intermetallic compounds.

  19. Structure, Energetics, Electronic, and Hydration Properties of Neutral and Anionic Al3O6, Al3O7, and Al3O8 Clusters

    E-print Network

    Pandey, Ravi

    on their structural and electronic properties. Our results, based on density functional calculations, reveal-coordinated Al sites. I. Introduction Aluminum oxide, Al2O3, traditionally referred to as alumina, is a very+ and O2- ions whose electrostatic interactions are primarily responsible for alumina's cohesive energy

  20. Interface/border trap characterization of Al2O3/AlN/GaN metal-oxide-semiconductor structures with an AlN interfacial layer

    NASA Astrophysics Data System (ADS)

    Liu, Shenghou; Yang, Shu; Tang, Zhikai; Jiang, Qimeng; Liu, Cheng; Wang, Maojun; Shen, Bo; Chen, Kevin J.

    2015-02-01

    We report the interface characterization of Al2O3/AlN/GaN MOS (metal-oxide-semiconductor) structures with an AlN interfacial layer. A thin monocrystal-like interfacial layer (AlN) is formed at the Al2O3/GaN to effectively block oxygen from the GaN surface and prevent the formation of detrimental Ga-O bonds. The suppression of Ga-O bonds is validated by X-ray photoelectron spectroscopy of the critical interface. Frequency-dispersion in C-V characteristics has been significantly reduced, owing to improved interface quality. Furthermore, using the conventional conductance method suitable for extracting the interface trap density Dit in MOS structures, Dit in the device with AlN was determined to be in the range of 1011-1012 eV-1 cm-2, showing one order of magnitude lower than that without AlN. Border traps near the gate-dielectric/GaN interface were identified and shown to be suppressed by the AlN interfacial layer as well.

  1. Enhanced spectral response of an AlGaN-based solar-blind ultraviolet photodetector with Al nanoparticles.

    PubMed

    Bao, Guanghong; Li, Dabing; Sun, Xiaojuan; Jiang, Mingming; Li, Zhiming; Song, Hang; Jiang, Hong; Chen, Yiren; Miao, Guoqing; Zhang, Zhiwei

    2014-10-01

    An enhanced spectral response was realized in an AlGaN-based solar-blind ultraviolet (SB-UV) detector using aluminum (Al) nanoparticles (NPs) of 20-60 nm. The peak responsivity of the detector (about 288 nm) with 60 nm Al NPs is more than two times greater than that of a detector without Al NPs under a 5-V bias, reaching 0.288 A/W. To confirm the enhancement mechanism of the Al NPs, extinction spectra were simulated using time-domain and frequency-domain finite-element methods. The calculation results show that the dipole surface plasmon resonance wavelength of the Al NPs is localized near the peak responsivity position of AlGaN-based SB-UV detectors. Thus, the improvement in the detectors can be ascribed to the localized surface plasmon resonance effect of the Al NPs. The localized electric field enhancement and related scattering effect result in the generation of more electron-hole pairs and thus a higher responsivity. In addition, the dark current of AlGaN-based SB-UV detectors does not increase after the deposition of Al nanoparticles. The results presented here is promising for applications of AlGaN-based SB-UV detectors. PMID:25322003

  2. Molecular and phenotypic characterization of Als1 and Als2 mutations conferring tolerance to acetolactate synthase herbicides in soybean

    PubMed Central

    Walter, Kay L; Strachan, Stephen D; Ferry, Nancy M; Albert, Henrik H; Castle, Linda A; Sebastian, Scott A

    2014-01-01

    BACKGROUND Sulfonylurea (SU) herbicides are effective because they inhibit acetolactate synthase (ALS), a key enzyme in branched-chain amino acid synthesis required for plant growth. A soybean line known as W4-4 was developed through rounds of seed mutagenesis and was demonstrated to have a high degree of ALS-based resistance to both post-emergence and pre-emergence applications of a variety of SU herbicides. This report describes the molecular and phenotypic characterization of the Als1 and Als2 mutations that confer herbicide resistance to SUs and other ALS inhibitors. RESULTS The mutations are shown to occur in two different ALS genes that reside on different chromosomes: Als1 (P178S) on chromosome 4 and Als2 (W560L) on chromosome 6 (P197S and W574L in Arabidopsis thaliana). CONCLUSION Although the Als1 and Als2 genes are unlinked, the combination of these two mutations is synergistic for improved tolerance of soybeans to ALS-inhibiting herbicides. © 2014 DuPont Pioneer. Pest Management Science published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:24425499

  3. Ion-beam mixing and thermal annealing of Al--Nb and Al--Ta thin films

    SciTech Connect

    Rai, A.K.; Bhattacharya, R.S.; Mendiratta, M.G.; Subramanian, P.R.; Dimiduk, D.M.

    1988-11-01

    Ion-beam mixing and thermal annealing of thin, alternating layers of Al and Nb, as well as Al and Ta, were investigated by selected area diffraction and Rutherford backscattering. The individual layer thicknesses were adjusted to obtain the overall compositions as Al/sub 3/Nb and Al/sub 3/Ta. The films were ion mixed with 1 MeV Au/sup +/ ions at a dose of 1 x 10/sup 16/ ions cm/sup -2/ . Uniform mixing and amorphization were achieved for both Al--Nb and Al--Ta systems. Equilibrium crystalline Al/sub 3/Nb and Al/sub 3/Ta phases were formed after annealing of ion mixed amorphous films at 400 /sup 0/C for 6 h. Unmixed films, however, remained unreacted at 400 /sup 0/C for 1 h. Partial reaction was observed in the unmixed film of Al--Nb at 400 /sup 0/C for 6 h. After annealing at 500 /sup 0/C for 1 h, a complete reaction and formation of Al/sub 3/Nb and Al/sub 3/Ta phases in the respective films were observed. The influence of thermodynamics on the phase formation by ion mixing and thermal annealing is discussed.

  4. Al-26 and O-16 in the early solar system - Clues from meteoritic Al2O3

    SciTech Connect

    Anders, E.; Lewis, R.S.; Virag, A.; Zinner, E. (Chicago, Univ., IL (USA) Washington Univ., Saint Louis, MO (USA))

    1991-06-01

    The study focuses on 26 Al2O3 grains up to 20 micron in size recovered from the Murchison C2 chrondite. It is observed that Mg-26/Mg-24 ranges up to 56 times the solar system ratio, but the initial Al-26/Al-27 ratios do not exceed the canonical maximum of 0.00005 in other meteoritic samples. It is concluded that this ratio represents the abundance of live Al-26 in the early solar system, not fossil radiogenic Mg-26 surviving from presolar times. The grains are shown to divide into three groups on the basis of Al-26, O-16, Ti, and V content, and distinctive correlations are found for Al-26 and O-16. An origin from at least three discrete components is suggested, two of which contained live Al-26. 24 refs.

  5. Al-26 and O-16 in the early solar system - Clues from meteoritic Al2O3

    NASA Technical Reports Server (NTRS)

    Anders, Edward; Lewis, Roy S.; Virag, Alois; Zinner, Ernst

    1991-01-01

    The study focuses on 26 Al2O3 grains up to 20 micron in size recovered from the Murchison C2 chrondite. It is observed that Mg-26/Mg-24 ranges up to 56 times the solar system ratio, but the initial Al-26/Al-27 ratios do not exceed the canonical maximum of 0.00005 in other meteoritic samples. It is concluded that this ratio represents the abundance of live Al-26 in the early solar system, not fossil radiogenic Mg-26 surviving from presolar times. The grains are shown to divide into three groups on the basis of Al-26, O-16, Ti, and V content, and distinctive correlations are found for Al-26 and O-16. An origin from at least three discrete components is suggested, two of which contained live Al-26.

  6. High quality semipolar (11{sup ¯}02) AlGaN/AlN quantum wells with remarkably enhanced optical transition probabilities

    SciTech Connect

    Ichikawa, S., E-mail: shuhei.ichikawa@optomater.kuee.kyoto-u.ac.jp; Iwata, Y.; Funato, M.; Kawakami, Y., E-mail: kawakami@kuee.kyoto-u.ac.jp [Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan); Nagata, S. [JFE Mineral Co. Ltd., Chiba 260-0826 (Japan)

    2014-06-23

    Adjusting the growth conditions from those for c-plane growth realizes high-quality semipolar (11{sup ¯}02) AlGaN/AlN quantum wells (QWs) with atomically smooth surfaces and abrupt interfaces on AlN substrates. Upon comparing the optical properties to those of c-plane QWs using time-integrated and time-resolved photoluminescence spectroscopy, the estimated internal electric field is much smaller in (11{sup ¯}02) AlGaN/AlN QWs than in c-plane QWs. Thus, (11{sup ¯}02) AlGaN/AlN QWs have narrower emission line widths and remarkably faster radiative recombination lifetimes, realizing highly efficient deep ultraviolet emissions.

  7. Effect of dislocations on electron mobility in AlGaN/GaN and AlGaN/AlN/GaN heterostructures

    SciTech Connect

    Kaun, Stephen W.; Burke, Peter G.; Kyle, Erin C. H.; Speck, James S. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Wong, Man Hoi; Mishra, Umesh K. [Electrical and Computer Engineering Department, University of California, Santa Barbara, California 93106 (United States)

    2012-12-24

    Al{sub x}Ga{sub 1-x}N/GaN (x = 0.06, 0.12, 0.24) and AlGaN/AlN/GaN heterostructures were grown on 6 H-SiC, GaN-on-sapphire, and free-standing GaN, resulting in heterostructures with threading dislocation densities of {approx}2 Multiplication-Sign 10{sup 10}, {approx}5 Multiplication-Sign 10{sup 8}, and {approx}5 Multiplication-Sign 10{sup 7} cm{sup -2}, respectively. All growths were performed under Ga-rich conditions by plasma-assisted molecular beam epitaxy. Dominant scattering mechanisms with variations in threading dislocation density and sheet concentration were indicated through temperature-dependent Hall measurements. The inclusion of an AlN interlayer was also considered. Dislocation scattering contributed to reduced mobility in these heterostructures, especially when sheet concentration was low or when an AlN interlayer was present.

  8. Improvement of the Electrochemical Behavior of Steel Surfaces Using a [Ti-Al/Ti-Al-N] n Multilayer System

    NASA Astrophysics Data System (ADS)

    Ipaz, L.; Aperador, W.; Caicedo, J. C.; Esteve, J.; Zambrano, G.

    2013-05-01

    The aim of this work is to improve the corrosion resistance of AISI D3 steel surfaces using a [Ti-Al/Ti-Al-N] n multilayer system deposited with different periods (?) and bilayer numbers ( n), via magnetron co-sputtering pulsed d.c. procedure, from a metallic (Ti-Al) binary target. The multilayer coatings were characterized by cross-sectional scanning electron microscopy that showed the modulation and microstructure of the [Ti-Al/Ti-Al-N] n multilayer system. The composition of the single Ti-Al and Ti-Al-N layer films was studied via x-ray photoelectron spectroscopy, where typical signals for Ti2p1/2, Ti2p, N1s, and Al2p3/2 were detected. The electrochemical properties were evaluated by electrochemical impedance spectroscopy and Tafel polarization curves. The optimal electrochemical behavior was obtained for the [Ti-Al/Ti-Al-N] n multilayered period of ? = 25 nm (100 bilayers). At these conditions, the maximum polarization resistance (1719.32 k? cm2) and corrosion rate (0.7 ?my) were 300 and 35 times higher than that of uncoated AISI D3 steel substrate (5.61 k? cm2 and 25 ?my, respectively). Finally, scanning electron microscopy was used to analyze the [Ti-Al/Ti-Al-N] n multilayered surface after the corrosive attack. The improvement effects in the electrochemical behavior of the AISI D3 coated with the [Ti-Al/Ti-Al-N] n multilayered coatings could be attributed to the number of interfaces that act as obstacles for the inward and outward diffusions of Cl- ions, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface.

  9. Shock induced reaction of Ni/Al nanopowder mixture.

    PubMed

    Meng, C M; Wei, J J; Chen, Q Y

    2012-11-01

    Nanopowder Ni/Al mixture (mixed in Al:Ni = 2:1 stoichiometry) was shock compressed by employing single and two-stage light gas gun. The particle size of Al and Ni are 100-200 nm and 50-70 nm respectively, morphologies of Al and Ni are sphere like either. Recovered product was characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis. According to the XRD spectrum, the mixed powder undergo complete reaction under shock compression, reaction product consist of Ni2Al3, NiAl and corundum structure Al2O3 compound. Grain size of Ni-Al compound is less than 100 nm. With the shock pressure increasing, the ratio of Ni2Al3 decreased obviously. The corundum crystal size is 400-500 nm according to the SEM observation. The results of shock recovery experiments and analysis show that the threshold pressure for reaction of nano size powder Ni/Al mixture is much less than that of micro size powder. PMID:23421276

  10. Inverse Thermal Analysis of Heat-Affected Zone in Al2129 and Al2198 Laser Welds

    NASA Astrophysics Data System (ADS)

    Zervaki, A. D.; Haidemenopoulos, G. N.; Lambrakos, S. G.

    2013-06-01

    Case study analyses of A12139 and Al2198 laser welds are presented. These analyses demonstrate the concept of constructing parameter spaces for prediction of properties within the heat-affected zone (HAZ) of welds using inverse modeling, which are in turn for process control. The construction of these parameter spaces consists of two procedures. One procedure entails calculation of a parameterized set of temperature histories by inverse analysis of the heat deposition occurring during welding. The other procedure entails correlating these temperature histories with a specific physical property of the weld that is measurable. The analyses presented here examines some characteristics of inverse modeling with respect to the prediction of hardness within the HAZ for deep penetration laser welding of the Aluminum alloys A12139 and Al2198. This study further demonstrates the feasibility of constructing a parameter space for the prediction of weld properties using weld cross section measurements that are independent of weld process conditions.

  11. High Performance Polarized Electron Photocathodes Based on InGaAlAs/AlGaAs Superlattices

    NASA Astrophysics Data System (ADS)

    Mamaev, Y. A.; Subashiev, A. V.; Yashin, Y. P.; Gerchikov, L. G.; Luh, D.; Maruyama, T.; Clendenin, J. E.; Ustinov, V. M.; Zhukov, A. E.

    2005-08-01

    Highly efficient emitters of polarized electrons based on the InAlGaAs/AlGaAs superlattice give an optimistic prognosis to explorations of such structures as the sources for accelerators. A new set of these SL structures with minimized conduction band offset was designed and recently tested. A new technology of surface protection in MBE growth leads to a significantly reduced heat-cleaning temperature. At these lowered cleaning temperatures, the thermal degradation of the working structure parameters is avoided. As a result a polarization P of up to 91% at corresponding quantum efficiency (QE) of 0.3% was achieved at room temperature. A 50% increase in the photocathode lifetime has been achieved with Sb coverage.

  12. Chemical shielding properties for BN, BP, AlN, and AlP nanocones: DFT studies

    NASA Astrophysics Data System (ADS)

    Mirzaei, Mahmoud; Yousefi, Mohammad; Meskinfam, Masoumeh

    2012-06-01

    The properties of boron nitride (BN), boron phosphide (BP), aluminum nitride (AlN), and aluminum phosphide (AlP) nanocones were investigated by density functional theory (DFT) calculations. The investigated structures were optimized and chemical shielding (CS) properties including isotropic and anisotropic CS parameters were calculated for the atoms of the optimized structures. The magnitudes of CS parameters were observed to be mainly dependent on the bond lengths of considered atoms. The results indicated that the atoms could be divided into atomic layers due to the similarities of their CS properties for the atoms of each layer. The trend means that the atoms of each layer detect almost similar electronic environments. Moreover, the atoms at the apex and mouth of nanocones exhibit different properties with respect to the other atomic layers.

  13. Kinetic energy distributions of sputtered neutral aluminum clusters: Al--Al[sub 6

    SciTech Connect

    Coon, S.R.; Calaway, W.F.; Pellin, M.J. (Argonne National Lab., IL (United States)); Curlee, G.A. (Trinity Univ., San Antonio, TX (United States). Dept. of Physics); White, J.M. (Texas Univ., Austin, TX (United States). Dept. of Chemistry and Biochemistry)

    1992-01-01

    Neutral aluminum clusters sputtered from polycrystalline aluminum were analyzed by laser postionization time-of-flight (TOF) mass spectrometry. The kinetic energy distributions of Al through Al[sub 6] were measured by a neutrals time-of-flight technique. The interpretation of laser postionization TOF data to extract velocity and energy distributions is presented. The aluminum cluster distributions are qualitatively similar to previous copper cluster distribution measurements from our laboratory. In contrast to the steep high energy tails predicted by the single- or multiple- collision models, the measured cluster distributions have high energy power law dependences in the range of E[sup [minus]3] to E[sup [minus]4.5]. Correlated collision models may explain the substantial abundance of energetic clusters that are observed in these experiments. Possible influences of cluster fragmentation on the distributions are discussed.

  14. Kinetic energy distributions of sputtered neutral aluminum clusters: Al--Al{sub 6}

    SciTech Connect

    Coon, S.R.; Calaway, W.F.; Pellin, M.J. [Argonne National Lab., IL (United States); Curlee, G.A. [Trinity Univ., San Antonio, TX (United States). Dept. of Physics; White, J.M. [Texas Univ., Austin, TX (United States). Dept. of Chemistry and Biochemistry

    1992-12-01

    Neutral aluminum clusters sputtered from polycrystalline aluminum were analyzed by laser postionization time-of-flight (TOF) mass spectrometry. The kinetic energy distributions of Al through Al{sub 6} were measured by a neutrals time-of-flight technique. The interpretation of laser postionization TOF data to extract velocity and energy distributions is presented. The aluminum cluster distributions are qualitatively similar to previous copper cluster distribution measurements from our laboratory. In contrast to the steep high energy tails predicted by the single- or multiple- collision models, the measured cluster distributions have high energy power law dependences in the range of E{sup {minus}3} to E{sup {minus}4.5}. Correlated collision models may explain the substantial abundance of energetic clusters that are observed in these experiments. Possible influences of cluster fragmentation on the distributions are discussed.

  15. Josephson effect in Al/Bi2Se3/Al coplanar hybrid devices

    NASA Astrophysics Data System (ADS)

    Galletti, L.; Charpentier, S.; Lucignano, P.; Massarotti, D.; Arpaia, R.; Tafuri, F.; Bauch, T.; Suzuki, Y.; Tagliacozzo, A.; Kadowaki, K.; Lombardi, F.

    2014-08-01

    The edge states of Topological Insulators (TI) are protected against backscattering, thanks to the topological properties arising from their band structure. Coupling a TI to a superconductor (S) can induce unconventional effects, including the creation of Majorana bound states (MBS). The fabrication of coplanar hybrid devices is a fundamental step to pave the way to the understanding of proximity effects in topologically non-trivial systems, and to a large variety of experiments aimed at the possible detection of MBS. We discuss the feasibility and some relevant properties of Al-Bi2Se3-Al coplanar proximity devices. Special attention is devoted to the design of the junction, aimed at enhancing the coupling between the electrodes and the TI.

  16. Near-infrared OPO in an AlGaAs/AlOx waveguide

    NASA Astrophysics Data System (ADS)

    Ozanam, C.; Savanier, M.; Lanco, L.; Lafosse, X.; Andronico, A.; Favero, I.; Ducci, S.; Leo, G.

    2013-12-01

    Within the ambitious quest for an electrically pumped version of the optical parametric oscillator (OPO), we demonstrate the first near-infrared integrated OPO in a direct gap semiconductor. This nonlinear device is based on a selectively oxidized GaAs/AlAs heterostructure, the same "AlOx" technology that is at the heart of VCSEL fabrication. The heterostructure and waveguide design allows for type-I form-birefringent phase matching, with a TM00 pump around 1 ?m and TE00 signal and idler around 2 ?m. Relying on the high non-resonant ?(2) of GaAs, relatively weak guided-wave optical losses, and monolithic SiO2/TiO2 dichroic Bragg mirrors, we observe a threshold of 210 mW at degeneracy in the continuous-wave regime, with a single-pass-pump doubly resonant scheme. Further improvement can be achieved by adopting a double-pump-pass scheme and, in a more fundamental way, by further optimizing the waveguide optical losses. The latter are induced by a not entirely mastered AlAs oxidation process and are of two distinct types: Rayleighlike scattering at signal and idler wavelength (? <= 1cm-1), due to the interface roughness between GaAs and AlOx layers; and absorption at pump wavelengths (? ? 3cm-1), due to volume defects in the GaAs layers adjacent to the aluminum oxide. This result marks a milestone for integrated nonlinear photonics and represents a significant step toward the goal of a broadly tunable coherent light source on chip.

  17. AlGaN/AlN-GaN-SL HEMTs with Multiple 2DEG Channels

    NASA Astrophysics Data System (ADS)

    Wille, Ada; Yacoub, Hady; Debald, Arne; Kalisch, Holger; Vescan, Andrei

    2014-11-01

    We report on a multichannel approach for AlGaN/GaN high-electron-mobility transistors (HEMTs) to increase the carrier mobility in the low and high sheet carrier concentration regimes. Between the AlGaN barrier and GaN buffer, alternating thin layers of AlN and GaN were inserted to create multiple two-dimensional electron gas (2DEG) channels. All samples were grown by metalorganic vapor-phase epitaxy (MOVPE) on sapphire substrates and compared with conventional single-channel HEMT with the same sheet carrier concentration. For low total 2DEG carrier concentrations (<8 × 1012 cm-2), the mobility for the multichannel HEMT was enhanced due to a reduction of ionized impurity and dislocation scattering, which originates from a backbarrier effect of the underlying AlN layers. In the high total carrier concentration regime (>8 × 1012 cm-2), a mobility improvement is attributed to distribution of the sheet charge into multiple 2DEG channels. This has been found to reduce the carrier concentration per individual channel, which leads to larger distance between 2DEG and heterointerfaces and therefore less impact of interface roughness and alloy scattering. With increasing number of channels, phonon scattering is also reduced due to lowering of the three-dimensional (3D) electron density, which results from the added volume of the multiple 2DEGs. With this approach, the HEMT mobility was increased from 1620 cm2 V-1 s-1 to 1960 cm2 V-1 s-1 for a triple-channel device at sheet carrier concentration of 7.5 × 1012 cm-2.

  18. Effects of Al ion implantation on the strength of Al 2O 3 particles

    Microsoft Academic Search

    Hisato Ogiso; Mikiko Yoshida; Shizuka Nakano; Jun Akedo

    2007-01-01

    Ion implantation into ceramic materials changes their mechanical properties. These changes are also affected by the substrate, however. To examine the effect of ion implantation without the effect of the substrate, in this study ?-Alumina particles (average diameter of 2 ?m) were implanted with 2.6 MeV Al ions at an ion dose of 1×1017 cm?2. The implantation introduced the defect, such as vacancies

  19. Angels in Islam: a commentary with selected translations of Jal?l al-D?n al-Suy???’s Al-?ab?’ik f? akhb?r almal?’ik (The Arrangement of the Traditions about Angels) 

    E-print Network

    Burge, Stephen Russell

    2010-01-01

    This thesis presents a commentary with selected translations of Jal?l al-D?n cAbd al- Ra?m?n al-Suy???’s Al-?ab?’ik f? akhb?r al-mal?’ik (The Arrangement of the Traditions about Angels). The work is a collection of around ...

  20. Diffusion in single crystal of melilite: interdiffusion of Al + Al vs. Mg + Si

    NASA Astrophysics Data System (ADS)

    Nagasawa, H.; Suzuki, T.; Ito, M.; Morioka, M.

    Interdiffusion coefficients of Al + Al vs. Mg + Si in the gehlenite-åkermanite system of melilite were determined by coupled annealing of synthesized end-member single crystals. The observed diffusion coefficients for a couple-annealed sample vary for about 2 orders of magnitude, showing strong dependence on the gehlenite-åkermanite composition: diffusion coefficient observed at 1350 °C, for example, is 3 × 10-13 cm2 s-1 at 5 mol% åkermanite composition (Ak5), increases to 2 × 10-11 cm2 s-1 at Ak80, and then decreases to 1 × 10-12 cm2 s-1 at Ak95. The diffusion coefficient-temperature relation indicates high activation energy of diffusion of about 420 kJ mol-1 for gehlenite-rich melilite. The observed diffusion coefficient-composition relation may be explained by a combination of (1) the diffusion coefficient-melting temperature relation (Flynn's rule) and (2) the feasibility of local charge compensation, which can possibly be maintained more easily in the intermediate chemical composition. The high activation energy value for gehlenitic melilite appears to correspond to the complex diffusion mechanism. The observed highly variable diffusion coefficients suggest that gehlenite-åkermanite zoning in the melilite crystals in Ca, Al-rich inclusions in the carbonaceous meteorites may provide a sensitive indicator for the thermal history of the inclusions.

  1. A study on the subgrain superplasticity of extruded Al-Al{sub 3}Ni eutectic alloy

    SciTech Connect

    Uan, J.Y.; Chen, L.H.; Lui, T.S.

    1997-02-01

    A directionally solidified Al-Al{sub 3}Ni eutectic alloy was extruded to obtain micron-size subgrains with [111] fiber texture. The extrusion temperature was varied to have different distributions of the Al{sub 3}Ni eutectic particles. Choosing the fiber axis as the loading axis, the tensile test results at 500 C indicate that the elongation is concave downward and strain-rate dependent. Reducing the number of intragranular particles increases the maximum elongation as well as the strain rate of maximum elongation. With the particles residing only intergranularly in the as-extruded state, the maximum elongation, which occurs under the initial strain rate of 6.3 {times} 10{sup {minus}3} s{sup {minus}1}, is about 300 pct. This subgrain superplasticity is associated with low strain-rate sensitivity but high resistance against strain softening. The fiber texture is always retained, and the microstructure reveals slip of long parallel dislocations. If intragranular particles are also present in the as-extruded state, the occurrence of dislocation tangling and dynamic recovery will give rise to early onset of strain softening and inferior ductility.

  2. Impact of SiO2 on Al–Al thermocompression wafer bonding

    NASA Astrophysics Data System (ADS)

    Malik, Nishant; Schjølberg-Henriksen, Kari; Poppe, Erik U.; Taklo, Maaike M. V.; Finstad, Terje G.

    2015-03-01

    Al–Al thermocompression bonding suitable for wafer level sealing of MEMS devices has been investigated. This paper presents a comparison of thermocompression bonding of Al films deposited on Si with and without a thermal oxide (SiO2 film). Laminates of diameter 150?mm containing device sealing frames of width 200?µm were realized. The wafers were bonded by applying a bond force of 36 or 60?kN at bonding temperatures ranging from 300–550?°C for bonding times of 15, 30 or 60?min. The effects of these process variations on the quality of the bonded laminates have been studied. The bond quality was estimated by measurements of dicing yield, tensile strength, amount of cohesive fracture in Si and interfacial characterization. The mean bond strength of the tested structures ranged from 18–61?MPa. The laminates with an SiO2 film had higher dicing yield and bond strength than the laminates without SiO2 for a 400?°C bonding temperature. The bond strength increased with increasing bonding temperature and bond force. The laminates bonded for 30 and 60?min at 400?°C and 60?kN had similar bond strength and amount of cohesive fracture in the bulk silicon, while the laminates bonded for 15?min had significantly lower bond strength and amount of cohesive fracture in the bulk silicon.

  3. Ferromagnetism in UCo1-xMnxAl and UCo1-xVxAl

    NASA Astrophysics Data System (ADS)

    Izmaylov, M.; Rafaja, D.; Sechovský, V.; Andreev, A. V.

    2002-01-01

    UCoAl is an itinerant 5 f-electron metamagnet with a tiny critical field of transition B c?0.4 T (at 1.3 K). Critical magnetic parameters of this material are strongly sensitive to chemical environment of U atoms. We present results of a pilot study of formation, crystal structure and magnetism of UCo1-xTxAl compounds for T=Mn and V, x?0.1. All these compounds have been found to be isostructural with the parent compound. Already for x=0.01 in both systems a spontaneous magnetization M s has been observed at low temperatures. Anomalies in the AC susceptibility as a function of temperature point to T c?28 and 25 K respectively for Mn and V doping. The ferromagnetism induced in UCo1-xTxAl compounds due to a substitution of light transition metal for Co is discussed within a model considering effects of varying 5 f-ligand hybridization on the stability of U 5 f-moment and on exchange interactions.

  4. 3DGRAPE/AL User's Manual

    NASA Technical Reports Server (NTRS)

    Sorenson, Reese L.; Alter, Stephen J.

    1995-01-01

    This document is a users' manual for a new three-dimensional structured multiple-block volume g generator called 3DGRAPE/AL. It is a significantly improved version of the previously-released a widely-distributed programs 3DGRAPE and 3DMAGGS. It generates volume grids by iteratively solving the Poisson Equations in three-dimensions. The right-hand-side terms are designed so that user-specific; grid cell heights and user-specified grid cell skewness near boundary surfaces result automatically, with little user intervention. The code is written in Fortran-77, and can be installed with or without a simple graphical user interface which allows the user to watch as the grid is generated. An introduction describing the improvements over the antecedent 3DGRAPE code is presented first. Then follows a chapter on the basic grid generator program itself, and comments on installing it. The input is then described in detail. After that is a description of the Graphical User Interface. Five example cases are shown next, with plots of the results. Following that is a chapter on two input filters which allow use of input data generated elsewhere. Last is a treatment of the theory embodied in the code.

  5. [Visiting nurse for a terminal ALS patient].

    PubMed

    Kitamikado, H; Sugihara, S; Enomoto, K; Sueda, M; Tanaka, T; Mori, H; Fukuyama, Y

    1999-12-01

    The authors' hospital is a 585-bed hospital under the direct management of the National Health Insurance System. The hospital has been providing visiting nurses for the past 8 years, who work from local medical centers and the Visiting Nurses Department. Thirty-seven patients have received such home care, among whom 8 had intractable disease. Patient S was a 46-year-old woman who suffered from amyotrophic lateral sclerosis (ALS). The onset of the disease was in April, 1993, when the patient experienced muscular atrophy in both legs and deteriorating muscular strength. The diagnosis was definitive in 1995. On March 1, 1998, the patient received emergency hospitalization for breathing difficulties and aspiration pneumonia, and on March 5 underwent tracheotomy. A cannula had to be inserted for tubal feeding, and the physician in charge explained to her family that her prognosis was 3 months. Both the patient and her family desired home care, and the patient returned home on April 11. Respecting the wishes of the patient, the visiting nurse provided support so that home treatment could be continued. In the end, the patient lived at home while receiving home treatment for 7 months. Through the support provided by the visiting nurse, efforts were made to keep the patient's condition stable, and she was able to continue home treatment and living at home for a higher quality of life. PMID:10630215

  6. ALS liquid hydrogen turbopump: Advanced Development Program

    NASA Technical Reports Server (NTRS)

    Shimp, Nancy R.; Claffy, George J.

    1989-01-01

    The point of departure (POD) turbopump concept was reviewed and finalized. The basis for the POD was the configuration presented in the Aerojet proposal. After reviewing this proposal concept, several modifications were made. These modifications include the following: (1) the dual pump discharge arrangement was changed to a single discharge; (2) commonality of the turbine inlet manifold with the advanced launch system (ALS) liquid oxygen (LOX) TPA was dropped for this program; (3) the turbine housing flange arrangement was improved by relocating it away from the first stage nozzles; (4) a ten percent margin (five percent diameter increase) was built into the impeller design to ensure meeting the required discharge pressure without the need for increasing speed; (5) a ten percent turbine power margin was imposed which is to be obtained by increasing turbine inlet pressure if required; and (6) the backup concept, as an alternative to the use of cast impellers, now incorporates forged/machined shrouded impellers, rather than the unshrouded type originally planned.

  7. A deep atmospheric eclipse of AL Velorum

    NASA Technical Reports Server (NTRS)

    Eaton, Joel A.

    1994-01-01

    I have obtained new International Ultraviolet Explorer (IUE) observations in 1992 to search for an accretion column in and to analyze an atmospheric eclipse of AL Vel, a low luminosity zeta Aurigae binary. Rich shell spectra recorded at three phases of atmospheric eclipse give column densities and excitation temperatures for the chromospheric gas. The chromospheric density falls off exponentially with a scale height of 3 solar radius, an order of magnitude greater than expected for support by thermal motions. Excitation temperatures at 2 - 5 scale heights into the chromosphere are approximately 7000 K, with Doppler widths near 17 km/s. Absorption features that could be formed in an accretion column were detected at phases 0.70 and 0.75 in a series of spectra spanning the range 0.63-0.80 in orbital phase. They imply a very slow acceleration of the wind, consistent with results for other zeta Aur binaries, but the wind speed implied is inconsistent with profiles of wind lines. The terminal velocity of this wind, greater than or approximately = 360 km/s, is higher than that in any of the other zeta Aur binaries. Wind and chromospheric features in 1992 were much more prominent than in 1988, which implies that both the wind and chromosphere were much more massive: we seem to have witnessed in 1992 a burst of activity with a mass-loss rate greater than 10(exp -8) solar mass/yr.

  8. Roll Casting of Al-25%Si

    SciTech Connect

    Haga, Toshio [Osaka Institute of Technology, Omiya Asahiku Osaka city 535-8585 (Japan); Harada, Hideto [Graduate School of Osaka Institute of Technology, Omiya Asahiku Osaka city 535-8585 (Japan); Watari, Hisaki [Gunma University, Kiryu city, 376-8515 (Japan)

    2011-05-04

    Strip casting of Al-25%Si strip was tried using an unequal diameter twin roll caster. The diameter of the lower roll (large roll) was 1000 mm and the diameter of the upper roll (small roll) was 250 mm. Roll material was mild steel. The sound strip could be cast at the speeds ranging from 8 m/min to 12 m/min. The strip did not stick to the roll without the parting material. The primary Si, which existed at centre area of the thickness direction, was larger than that which existed at other area. The size of the primary Si was smaller than 0.2 mm. Eutectic Si was smaller 5 {mu}m. The as-cast strip was ranging from 2 mm to 3 mm thick and its width was 100 mm. The as-cast strip could be hot rolled down to 1 mm. The hot rolled strip was cold rolled. The primary Si became smaller and the pore occurred around the primary Si after the rolling.

  9. Roll Casting of Al-25%Si

    NASA Astrophysics Data System (ADS)

    Haga, Toshio; Harada, Hideto; Watari, Hisaki

    2011-05-01

    Strip casting of Al-25%Si strip was tried using an unequal diameter twin roll caster. The diameter of the lower roll (large roll) was 1000 mm and the diameter of the upper roll (small roll) was 250 mm. Roll material was mild steel. The sound strip could be cast at the speeds ranging from 8 m/min to 12 m/min. The strip did not stick to the roll without the parting material. The primary Si, which existed at centre area of the thickness direction, was larger than that which existed at other area. The size of the primary Si was smaller than 0.2 mm. Eutectic Si was smaller 5 ?m. The as-cast strip was ranging from 2 mm to 3 mm thick and its width was 100 mm. The as-cast strip could be hot rolled down to 1 mm. The hot rolled strip was cold rolled. The primary Si became smaller and the pore occurred around the primary Si after the rolling.

  10. Reactive codoping of GaAlInP compound semiconductors

    DOEpatents

    Hanna, Mark Cooper (Boulder, CO); Reedy, Robert (Golden, CO)

    2008-02-12

    A GaAlInP compound semiconductor and a method of producing a GaAlInP compound semiconductor are provided. The apparatus and method comprises a GaAs crystal substrate in a metal organic vapor deposition reactor. Al, Ga, In vapors are prepared by thermally decomposing organometallic compounds. P vapors are prepared by thermally decomposing phospine gas, group II vapors are prepared by thermally decomposing an organometallic group IIA or IIB compound. Group VIB vapors are prepared by thermally decomposing a gaseous compound of group VIB. The Al, Ga, In, P, group II, and group VIB vapors grow a GaAlInP crystal doped with group IIA or IIB and group VIB elements on the substrate wherein the group IIA or IIB and a group VIB vapors produced a codoped GaAlInP compound semiconductor with a group IIA or IIB element serving as a p-type dopant having low group II atomic diffusion.

  11. Cost-Effective TiAl based Materials

    NASA Technical Reports Server (NTRS)

    Moxson, V. S.; Sun, Fusheng; Draper, Susan L.; Froes, F. H.; Duz, V.

    2003-01-01

    Because of their inherent low ductility, TiAl-based materials are difficult to fabricate, especially thin gage titanium gamma aluminide (TiAl) sheet and foil. In this paper, an innovative powder metallurgy approach for producing cost-effective thin gage TiAl sheets (with 356 mm long and 235 mm wide, and a thickness of 0.74, 1.09, 1.55, and 2.34 mm, respectively) is presented. The microstructures and tensile properties at room and elevated temperatures of the thin gage TiAl are studied. Results show that these TiAl sheets have a relatively homogenous chemistry, uniform microstructure, and acceptable mechanical properties. This work demonstrates a cost-effective method for producing both flat products (sheet/foil) and complex chunky parts of TiAl for various advanced applications including aerospace and automotive industries.

  12. Al environment in tectosilicate and peraluminous glasses: A 27Al MQ-MAS NMR, Raman, and XANES investigation

    NASA Astrophysics Data System (ADS)

    Neuville, Daniel R.; Cormier, Laurent; Massiot, Dominique

    2004-12-01

    Tecto-aluminosilicate and peraluminous glasses have been prepared by conventional and laser heating techniques, respectively, in the CaO-Al 2O 3-SiO 2 system. The structure of these glasses were studied using Raman spectroscopy, X-ray absorption at the Al K-edge and 27Al NMR spectroscopy with two different high fields (400 and 750 MHz). Raman spectroscopy and X-ray absorption are techniques sensitive to the network polymerization and, in particular, show different signal as a function of silica content. However, these two techniques are less sensitive than NMR to describe the local aluminium environment. For tectosilicate glasses, aluminium in five-fold coordination, [5]Al, was found and a careful quantification allows the determination of a significant amount of [5]Al (7% in the anorthite glass). The proportion of [5]Al increases for the peraluminous glasses with small amounts (<2%) of six-fold coordination, [6]Al. The presence of [5]Al agrees with previous observations of the existence of nonbridging oxygens (NBOs) in tectosilicate compositions. However, the proportion of [5]Al in the present study indicates that no major proportion of triclusters (oxygen coordinated to three (Si,Al)O 4 tetrahedra) is required to explain these NBOS.

  13. Characterization of superconducting single-electron transistors with small Al/AlO_{x}/V Josephson junctions

    NASA Astrophysics Data System (ADS)

    Shimada, Hiroshi; Miyawaki, Kenji; Hagiwara, Ayano; Takeda, Kouichi; Mizugaki, Yoshinao

    2014-11-01

    Superconducting single-electron transistors (SSETs) composed of small Al/AlOx/V junctions were fabricated, and their transport properties were investigated. The device with an Al island exhibited a supercurrent that was 2e-periodic in the gate charge while that with a V island showed a periodicity of e, where e is an elementary charge. The Josephson-quasiparticle (JQP)-cycle current appeared at the bias voltage V in the range {{? }Al}+{{E}c}\\lt e|V|\\lt {{? }Al}+3{{E}c}, where {{? }Al} is the superconducting gap of Al and {{E}c} is the charging energy of an elementary charge. This is different from the commonly accepted range for the JQP current such as that in the case of an all Al SSET. There also appeared a large leakage current at 2{{? }Al}?slant e|V|\\lt 2({{? }V}+{{? }Al}+{{E}c}), where {{? }V} is the superconducting gap of V. All these properties are accounted for by considering the finite subgap quasiparticle density of states in the V electrode.

  14. Preparation of Al-Cr-Fe Coatings by Heat Treatment of Electrodeposited Cr/Al Composite Coatings

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Chen, Chang'an; Zhang, Guikai; Rao, Yongchu; Ling, Guoping

    Al-Cr-Fe coatings have been widely used in the surface engineering field of materials, due to their excellent corrosion resistance to water vapor and fused salt deposits. In this study, a new two-step approach was developed to prepare Al-Cr-Fe coatings on surfaces of SUS430 stainless steels. First, the Cr/Al composite coatings were prepared by electrodepositing Cr from aqueous solution then electrodepositing Al from AlCl3-1-ethyl-3-methyl-imidazolium chloride (AlCl3-EMIC) ionic liquid on SUS430 stainless steel substrate. In the second, heat treatment of the Cr/Al composite coatings was carried out to acquire Al-Cr-Fe coatings. Effects of the thickness of Cr/Al composite coatings, the time and temperature of heat treatment on composition and phase structure of alloy layers were studied by using scanning electron microscope (SEM), backscattered electron (BSE), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The structure transformation process and formation mechanism of Al-Cr-Fe coatings were discussed.

  15. Probing the Structure and Bonding in Al6N- and Al6N by Photoelectron Spectroscopy and Ab Initio Calculations

    SciTech Connect

    Averkiev, Boris B.; Boldyrev, Alexander I.; Li, Xi; Wang, Lai S.

    2007-01-11

    The electronic and geometrical structure of a nitrogen-doped Al6 - cluster (Al6N-) is investigated using photoelectron spectroscopy and ab initio calculations. Photoelectron spectra of Al6N- have been obtained at three photon energies with seven resolved spectral features. The electron affinity of Al6N has been determined to be 2.58 (0.04 eV. Global minimum structure searches for A6N- and its corresponding neutral form are performed using several theoretical methods. Vertical electron detachment energies, calculated using three different methods for the lowest energy structure and a low-lying isomer, are compared with the experimental data. The ground-state structure of Al6N- is established from the joint experimental and theoretical study to consist of an Al2 dimer bonded to the top of a quasi-planar tetracoordinated N unit, Al4N-, or it can be viewed as a distorted trigonal prism structure with the N atom bonded in one of the prism faces. For neutral Al6N, three low-lying isomers are found to compete for the global minimum, two of which are built from the tetracoordinated Al4N unit. The chemical bonding in Al6N- is discussed on the basis of molecular orbital and natural bond analyses.

  16. Effect of transition metal additives on electronic structure and elastic properties of TiAl and Ti3Al

    NASA Astrophysics Data System (ADS)

    Music, Denis; Schneider, Jochen M.

    2006-11-01

    We have studied the correlation between the electronic structure and elastic properties of ?-TiAl (space group P4/mmm , prototype AuCu) as well as ?2-Ti3Al (space group P63/mmc , prototype Ni3Sn ) alloyed with VB (V, Nb, Ta), VIB (Cr, Mo, W), and VIIB (Mn) transition metals, using ab initio calculations. Upon alloying, the bulk modulus is increased as compared to unalloyed phases. This can be understood based on the partial density of states analysis. The bonding in ?-TiAl and ?2-Ti3Al is mainly metallic, due to Ti d-Ti d interactions, and there is a weak covalent contribution, due to hybridization between Al p and Ti d orbitals. This increase in the bulk modulus is due to band filling. On the other hand, the values of the elastic constant C44 are comparable with or lower than those of ?-TiAl and ?2-Ti3Al . Upon alloying, the metallic bonding character is enhanced and the covalent bonding character is reduced. The bulk-modulus-to- C44 ratio is hence larger as compared to the unalloyed substances. The largest value is obtained for the Mn substitution, resulting in a 13.5% and 19.6% increase for ?-TiAl and ?2-Ti3Al , respectively. These results are of relevance to the tailoring of the mechanical properties of TiAl alloys.

  17. 93Nb- and 27Al-NMR/NQR studies of the praseodymium based PrNb2Al20

    NASA Astrophysics Data System (ADS)

    Kubo, Tetsuro; Kotegawa, Hisashi; Tou, Hideki; Higashinaka, Ryuji; Nakama, Akihiro; Aoki, Yuji; Sato, Hideyuki

    2015-03-01

    We report a study of 93Nb- and 27Al-nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) in a praseodymium based compound PrNb2Al20. The observed NMR line at around 3 T and 30 K shows a superposition of typical powder patterns of one Nb signal and at least two Al signals. 93Nb-NMR line could be reproduced by using the previously reported NQR frequency ?Q ? 1.8MHz and asymmetry parameter ? ? 0 [Kubo T et al 2014 JPS Conf. Proc. 3 012031]. From 27Al-NMR/NQR, NQR parameters are obtained to be ?Q,A ? 1.53 MHz, and ?A ? 0.20 for the site A, and ?Q,B ? 2.28 MHz, and ?B ? 0.17 for the site B. By comparing this result with the previous 27Al-NMR study of PrT2Al20 (T = Ti, V) [Tokunaga Y et al 2013 Phys. Rev. B 88 085124], these two Al site are assigned to the two of three crystallographycally inequivalent Al sites.

  18. Defect analysis in AlGaN layers on AlN templates obtained by epitaxial lateral overgrowth

    NASA Astrophysics Data System (ADS)

    Mogilatenko, Anna; Küller, Viola; Knauer, Arne; Jeschke, J.; Zeimer, Ute; Weyers, Markus; Tränkle, Günther

    2014-09-01

    The defect distribution in thick AlN layers obtained by epitaxial lateral overgrowth (ELO-AlN) has been analyzed as a function of the miscut direction of the patterned sapphire substrate. A 0.25° miscut toward the sapphire a-plane leads to formation of smooth ELO-AlN layers containing vertical coalescence grain boundaries and exhibiting an almost homogeneous threading dislocation (TD) distribution with a TD density ranging from 5×108 cm-2 to 8×108 cm-2. In contrast, a 0.25° miscut toward the sapphire m-plane results in formation of periodically arranged macrosteps on the surface of the coalesced ELO-AlN layers as well as formation of inclined coalescence grain boundaries leading to an inhomogeneous TD distribution. A subsequent AlxGa1-xN deposition onto ELO-AlN template with surface macrosteps leads to Ga enrichment on the step sidewalls and, for lower Al-contents (e.g. x=0.5), even to additional defect formation. For higher Al contents (e.g. x=0.8) no additional threading dislocations are formed in the AlGaN layers and the observed TD density corresponds to that of the ELO-AlN template: less than 108 cm-2 in the wing regions and from 6×108 cm-2 to 9×108 cm-2 above the ridges. Compressive strain during growth of Al0.8Ga0.2N on ELO-AlN tends to be compensated by threading dislocation inclination. However, due to the low TD densities the inclination angles are more than 3 times larger than those observed in Al0.8Ga0.2N layers on planar AlN/sapphire templates.

  19. Hard boride coating on iron aluminide (FeAl)

    Microsoft Academic Search

    Erdinç Ekmekçiler; Aytekin Polat; Metin Usta

    2008-01-01

    The mechanical properties of borided iron aluminide (FeAl) were investigated. Boronizing was carried out in a solid medium consisting of Ekabor powders at 940 °C for 2, 4 and 8 h. The formation of FeB on the surface of FeAl was confirmed by XRD analysis. Metallographic studies revealed an almost saw-tooth-like and compact boride layer on the FeAl. The thickness of boride

  20. CuAlSe_2 Thin Films Obtained by Chalcogenization

    Microsoft Academic Search

    S. Marsillac; K. Benchouk; C. El Moctar; J. C. Bernède; J. Pouzet; A. Khellil; M. Jamali

    1997-01-01

    CuAlSe2 thin films have been synthesized by chalcogenization of thin Cu and Al layers sequentially deposited by evaporation under vacuum. It is shown that CuAlSe2 films are obtained with some Cu{2-delta}Se2 and Se phases present at the surface. These surface phases are suppressed by annealing under vacuum and by chemical etching in a KCN solution. At the end of the