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Sample records for high al tolerant

  1. Genetic dissection of Al tolerance QTLs in the maize genome by high density SNP scan

    Science.gov (United States)

    Aluminum (Al) toxicity is an important limitation to food security in the tropical and subtropical regions. High Al saturation in acid soils limits root development and its ability to uptake water and nutrients. In this study, we present a genome scan for Al tolerance loci with over 50,000 GBS-based...

  2. Nuclear Energy Advanced Modeling and Simulation (NEAMS) Accident Tolerant Fuels High Impact Problem: Coordinate Multiscale FeCrAl Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Gamble, K. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hales, J. D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, Y. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Andersson, D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Capolungo, L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wirth, B. D. [Univ. of Tennessee, Knoxville, TN (United States)

    2017-07-26

    Since the events at the Fukushima-Daiichi nuclear power plant in March 2011 significant research has unfolded at national laboratories, universities and other institutions into alternative materials that have potential enhanced ac- cident tolerance when compared to traditional UO2 fuel zircaloy clad fuel rods. One of the potential replacement claddings are iron-chromium-alunimum (FeCrAl) alloys due to their increased oxidation resistance [1–4] and higher strength [1, 2]. While the oxidation characteristics of FeCrAl are a benefit for accident tolerance, the thermal neu- tron absorption cross section of FeCrAl is about ten times that of Zircaloy. This neutronic penalty necessitates thinner cladding. This allows for slightly larger pellets to give the same cold gap width in the rod. However, the slight increase in pellet diameter is not sufficient to compensate for the neutronic penalty and enriching the fuel beyond the current 5% limit appears to be necessary [5]. Current estimates indicate that this neutronic penalty will impose an increase in fuel cost of 15-35% [1, 2]. In addition to the neutronic disadvantage, it is anticipated that tritium release to the coolant will be larger because the permeability of hydrogen in FeCrAl is about 100 times higher than in Zircaloy [6]. Also, radiation-induced hardening and embrittlement of FeCrAl need to be fully characterized experimentally [7]. Due to the aggressive development schedule for inserting some of the potential materials into lead test assemblies or rods by 2022 [8] multiscale multiphysics modeling approaches have been used to provide insight into these the use of FeCrAl as a cladding material. The purpose of this letter report is to highlight the multiscale modeling effort for iron-chromium-alunimum (FeCrAl) cladding alloys as part of the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program through its Accident Tolerant Fuel (ATF) High Impact Problem (HIP). The approach taken throughout the HIP is to

  3. estigma tolerable al estigma intolerable

    Directory of Open Access Journals (Sweden)

    Nelson Arteaga Botello

    2006-01-01

    cristalización pasa por dos referentes de interacción y relación social al interior del espacio escolar. El primero está constituido por parámetros de normalidad y anormalidad a partir de la localización de estigmas. El segundo se encuentra, a contrapelo de la tendencia anterior, tratando de diluir los efectos de los estigmas al señalarlos como una práctica de tipificación social intolerable o inaceptable.

  4. Robust Design by Antioptimization for Parameter Tolerant GaAs/AlOx High Contrast Grating Mirror for VCSEL Application

    CERN Document Server

    Chevallier, Christyves; Fressengeas, Nicolas; Jacquet, Joel

    2013-01-01

    A GaAs/AlOx high contrast grating structure design which exhibits a 99.5% high reflectivity for a 425nm large bandwidth is reported. The high contrast grating (HCG) structure has been designed in order to enhance the properties of mid-infrared VCSEL devices by replacing the top Bragg mirror of the cavity. A robust optimization algorithm has been implemented to design the HCG structure not only as an efficient mirror but also as a robust structure against the imperfections of fabrication. The design method presented here can be easily adapted for other HCG applications at different wavelengths.

  5. Second Annual Progress Report on Radiation Tolerance of Controlled Fusion Welds in High Temperature Oxidation Resistant FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Briggs, Samuel A. [Univ. of Wisconsin, Madison, WI (United States)

    2016-12-30

    The present report summarizes and discusses the current results and on-going activity towards developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability under the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program.

  6. First Annual Progress Report on Radiation Tolerance of Controlled Fusion Welds in High Temperature Oxidation Resistant FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hu, Xunxiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    The present report summarizes and discusses the first year efforts towards developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability under the Department of Energy (DOE) Nuclear Energy Enabling Technologies (NEET) program. Significant efforts have been made within the first year of this project including the fabrication of seven candidate FeCrAl alloys with well controlled chemistry and microstructure, the microstructural characterization of these alloys using standardized and advanced techniques, mechanical properties testing and evaluation of base alloys, the completion of welding trials and production of weldments for subsequent testing, the design of novel tensile specimen geometry to increase the number of samples that can be irradiated in a single capsule and also shorten the time of their assessment after irradiation, the development of testing procedures for controlled hydrogen ingress studies, and a detailed mechanical and microstructural assessment of weldments prior to irradiation or hydrogen charging. These efforts and research results have shown promise for the FeCrAl alloy class as a new nuclear grade alloy class.

  7. Selection and characterisation of high ethanol tolerant ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-12-17

    Dec 17, 2008 ... High level ethanol tolerant Saccharomyces yeast, Orc 6, was investigated for its potential ... bacteria for ethanol production, yeast is still the primary choice for ..... who reported high invertase activity with S. cerevisiae.

  8. 76 FR 56648 - Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Tolerance Actions

    Science.gov (United States)

    2011-09-14

    ... AGENCY 40 CFR Part 180 Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Tolerance... certain tolerances for atrazine, setting a revocation date for specific endosulfan tolerances, and making... parathion, and N,N-diethyl-2-(4- methylbenzyloxy)ethylamine, modify certain tolerances for atrazine, set a...

  9. Genetic mapping of a 7R Al tolerance QTL in triticale (x Triticosecale Wittmack).

    Science.gov (United States)

    Niedziela, A; Bednarek, P T; Labudda, M; Mańkowski, D R; Anioł, A

    2014-02-01

    Triticale (x Triticosecale Wittmack) is a relatively new cereal crop. In Poland, triticale is grown on 12 % of arable land ( http://www.stat.gov.pl ). There is an increasing interest in its cultivation due to lowered production costs and increased adaptation to adverse environmental conditions. However, it has an insufficient tolerance to the presence of aluminum ions (Al(3+)) in the soil. The number of genes controlling aluminum tolerance in triticale and their chromosomal location is not known. Two F2 mapping biparental populations (MP1 and MP15) segregating for aluminum (Al) tolerance were tested with AFLP, SSR, DArT, and specific PCR markers. Genetic mapping enabled the construction of linkage groups representing chromosomes 7R, 5R and 2B. Obtained linkage groups were common for both mapping populations and mostly included the same markers. Composite interval mapping (CIM) allowed identification of a single QTL that mapped to the 7R chromosome and explained 25 % (MP1) and 36 % (MP15) of phenotypic variation. The B1, B26 and Xscm150 markers were 0.04 cM and 0.02 cM from the maximum of the LOD function in the MP1 and MP15, respectively and were highly associated with aluminum tolerance as indicated by Kruskal-Wallis nonparametric test. Moreover, the molecular markers B1, B26, Xrems1162 and Xscm92, previously associated with the Alt4 locus that encoded an aluminum-activated malate transporter (ScALMT1) that was involved in Al tolerance in rye (Secale cereale) also mapped within QTL. Biochemical analysis of plants represented MP1 and MP15 mapping populations confirmed that the QTL located on 7R chromosome in both mapping populations is responsible for Al tolerance.

  10. Molecular Characterization of Atlas 66-Derived Wheat Near-Isogenic Lines Contrasting in Aluminum (Al) Tolerance

    Institute of Scientific and Technical Information of China (English)

    GUO Pei-guo; BAI Gui-hua; LI Rong-hua; Brett Carver; Michael Baum

    2007-01-01

    Aluminum (Al) toxicity is the major limiting factor for wheat growth in acidic soils. Genetic improvement of Al tolerance is one of the most cost-effective solutions to improve wheat productivity. The objective of this study was to characterize near isogenic lines (NILs) contrasting in Al tolerance derived from Atlas 66 in the backgrounds of Al-sensitive cultivars Chisholm and Century using amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR). A total of 200 AFLP and 88 SSR primer pairs were screened and 12 markers (11 AFLPs and one SSR) were associated with Altolerance in NILs of at least one recurrent parental background. Among them, nine were linked to Al tolerance in the Chisholm-derived NILs, seven were associated with Al-tolerance in the Century-derived NILs, and three AFLPs derived from the primer combinations of pAG/mGCAG, pCAG/mAGC and pGTG/mGCG, and one SSR, Xwmc331 on chromosome4D, associated with Al tolerance in NILs of both recurrent parental backgrounds. Those common markers across two backgrounds may be the major marker loci associated with Al-tolerance in Atlas 66 and could be useful for marker-assisted breeding to improve Al tolerance in wheat. In addition, evaluation of Al tolerance among different genotypes using hematoxylin stain and relative root growth revealed that Atlas 66 was more tolerant to Al stress than the NILs, therefore suggested that the Al-tolerant NILs might not carry all Al-tolerance loci from Atlas 66 and inheritance of Al tolerance in Atlas 66 is more likely multigenic.

  11. Status Report on Irradiation Capsules Containing Welded FeCrAl Specimens for Radiation Tolerance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-02-26

    This status report provides the background and current status of a series of irradiation capsules, or “rabbits”, that were designed and built to test the contributions of microstructure, composition, damage dose, and irradiation temperature on the radiation tolerance of candidate FeCrAl alloys being developed to have enhanced weldability and radiation tolerance. These rabbits will also test the validity of using an ultra-miniature tensile specimen to assess the mechanical properties of irradiated FeCrAl base metal and weldments. All rabbits are to be irradiated in the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL) to damage doses up to ≥15 dpa at temperatures between 200-550°C.

  12. 76 FR 25281 - Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Proposed Tolerance Actions

    Science.gov (United States)

    2011-05-04

    ... AGENCY 40 CFR Part 180 Atrazine, Chloroneb, Chlorpyrifos, Clofencet, Endosulfan, et al.; Proposed..., modify certain tolerances for atrazine, establish tolerances for endosulfan, and make minor revisions to..., EPA is proposing to modify certain tolerances for the herbicide atrazine. In addition, EPA is...

  13. Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes

    Institute of Scientific and Technical Information of China (English)

    毛传澡; 杨玲; 郑炳松; 吴运荣; 刘非燕; 易可可; 吴平

    2004-01-01

    Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and I QTL for root length under Al stress is identical on chromosome I after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for Al tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four Al induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL.

  14. Global Transcriptome Analysis Reveals Distinct Aluminum-Tolerance Pathways in the Al-Accumulating Species Hydrangea macrophylla and Marker Identification.

    Directory of Open Access Journals (Sweden)

    Haixia Chen

    Full Text Available Hydrangea (Hydrangea macrophylla is a well known Al-accumulating plant, showing a high level of aluminum (Al tolerance and accumulation. Although the physiological mechanisms for detoxification of Al and the roles of Al in blue hydrangea sepals have been reported, the molecular mechanisms of Al tolerance and accumulation are poorly understood in hydrangea. In this study, we conducted a genome-wide transcriptome analysis of Al-response genes in the roots and leaves of hydrangea by RNA sequencing (RNA-seq. The assembly of hydrangea transcriptome provides a rich source for gene identification and mining molecular markers, including single nucleotide polymorphism (SNP and simple sequence repeat (SSR. A total of 401,215 transcripts with an average length of 810.77 bp were assembled, generating 256,127 unigenes. After annotation, 4,287 genes in the roots and 730 genes in the leaves were up-regulated by Al exposure, while 236 genes in the roots and 719 genes in the leaves were down-regulated, respectively. Many transporters, including MATE and ABC families, were involved in the process of Al-citrate complex transporting from the roots in hydrangea. A plasma membrane Al uptake transporter, Nramp aluminum transporter was up-regulated in roots and leaves under Al stress, indicating it may play an important role in Al tolerance by reducing the level of toxic Al. Although the exact roles of these candidate genes remain to be examined, these results provide a platform for further functional analysis of the process of detoxification of Al in hydrangea.

  15. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas

    plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, could provide a sustainable solution for cost-effective digestion of abundant ammonia-rich wastes. The aim...... of the current study was to isolate and identify methanogenic cultures tolerant to high ammonia concentrations. A mixed methanogenic population was stepwise exposed to ammonia concentrations (1 to 9.26 g NH4+-N L-1) during an enrichment process with successive batch cultivations. The methanogenic population...... was derived from a full scale biogas reactor (Hashøj, Denmark), fed with 75% animal manure and 25% food industries organic waste. Basal anaerobic medium was used for the enrichment along with sodium acetate (1 g HAc L-1) as a carbon source. Fluorescence insitu hybridization (FISH) was used to determine...

  16. The location of aluminium in protoplasts and suspension cells taken from Coffea arabica L. with different tolerance of Al.

    Science.gov (United States)

    Ramírez-Benítez, J Efraín; Hernández-Sotomayor, S M Teresa; Muñoz-Sánchez, J Armando

    2009-11-01

    Biotechnological advances in coffee research (in vitro manipulation, multiplication, generation and development of transgenic coffee plants with specific traits like high yield and good quality) have contributed to description of the metabolic pathways involved in the response mechanisms to environmental factors like abiotic stress. Coffea arabica L. plants grow in acidic soils, and therefore aluminium (Al) toxicity is a major negative impact on crop productivity. To understand Al toxicity mechanisms in cells via the Al absorption kinetic, we isolated protoplasts from two C. arabica L. suspension cell lines: Al-sensitive (L2) and Al-tolerant (LAMt). Protoplasts of LAMt line exhibited lower Al absorption levels than protoplasts of the L2 line. Use of two fluorescent tracers (morin and calcofluor white) indicated that Al interacts with internal cell structures, such as the plasma membrane and nucleus, with differences in both cell lines. Al-tolerance in the LAMt is probably associated with the cell wall as well as intracellular structures. These data will help to better understand Al toxicity in C. arabica, and Al toxicity mechanisms in plant cells.

  17. Development of ODS FeCrAl alloys for accident-tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoelzer, David T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Unocic, Kinga A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-18

    FeCrAl alloys are prime candidates for accident-tolerant fuel cladding due to their excellent oxidation resistance up to 1400 C and good mechanical properties at intermediate temperature. Former commercial oxide dispersion strengthened (ODS) FeCrAl alloys such as PM2000 exhibit significantly better tensile strength than wrought FeCrAl alloys, which would alloy for the fabrication of a very thin (~250 m) ODS FeCrAl cladding and limit the neutronic penalty from the replacement of Zr-based alloys by Fe-based alloys. Several Fe-12-Cr-5Al ODS alloys where therefore fabricated by ball milling FeCrAl powders with Y2O3 and additional oxides such as TiO2 or ZrO2. The new Fe-12Cr-5Al ODS alloys showed excellent tensile strength up to 800 C but limited ductility. Good oxidation resistance in steam at 1200 and 1400 C was observed except for one ODS FeCrAl alloy containing Ti. Rolling trials were conducted at 300, 600 C and 800 C to simulate the fabrication of thin tube cladding and a plate thickness of ~0.6mm was reached before the formation of multiple edge cracks. Hardness measurements at different stages of the rolling process, before and after annealing for 1h at 1000 C, showed that a thinner plate thickness could likely be achieved by using a multi-step approach combining warm rolling and high temperature annealing. Finally, new Fe-10-12Cr-5.5-6Al-Z gas atomized powders have been purchased to fabricate the second generation of low-Cr ODS FeCrAl alloys. The main goals are to assess the effect of O, C, N and Zr contents on the ODS FeCrAl microstructure and mechanical properties, and to optimize the fabrication process to improve the ductility of the 2nd gen ODS FeCrAl while maintaining good mechanical strength and oxidation resistance.

  18. Rapidly evolving microorganisms with high biofuel tolerance

    Science.gov (United States)

    Vyawahare, Saurabh; Zhang, Qiucen; Lang, Wendy; Austin, Robert

    2012-02-01

    Replacing non-renewable energy sources is one of the biggest and most exciting challenges of our generation. Algae and bacteria are poised to become major renewable biofuels if strains can be developed that provide a high,consistent and robust yield of oil. One major stumbling block towards this goal is the lack of tolerance to high concentrations of biofuels like isobutanol. Using traditional bioengineering techniques to remedy this face the hurdle of identifying the correct pathway or gene to modify. But the multiplicity of interactions inside a cell makes it very hard to determine what to modify a priori. Instead, we propose a technology that does not require prior knowledge of the genes or pathways to modify. In our approach that marries microfabrication and ecology, spatial heterogeneity is used as a knob to speed up evolution in the desired direction. Recently, we have successfully used this approach to demonstrate the rapid emergence of bacterial antibiotic resistance in as little as ten hours. Here, we describe our experimental results in developing new strains of micro-organisms with high oil tolerance. Besides biofuel production, our work is also relevant to oil spill clean-ups.

  19. High Pain Tolerance Tied to 'Silent' Heart Attack Risk

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_162666.html High Pain Tolerance Tied to 'Silent' Heart Attack Risk Unusual symptoms ... is. But the new findings suggest that pain tolerance might be a factor. Using a standard test ...

  20. High Caloric Diet for ALS Patients: High Fat, High Carbohydrate or High Protein

    Directory of Open Access Journals (Sweden)

    Sarvin Sanaie

    2015-01-01

    Full Text Available ALS is a fatal motor neurodegenerative disease characterized by muscle atrophy and weakness, dysarthria, and dysphagia. The mean survival of ALS patients is three to five years, with 50% of those diagnosed dying within three years of onset (1. A multidisciplinary approach is crucial to set an appropriate plan for metabolic and nutritional support in ALS. Nutritional management incorporates a continuous assessment and implementation of dietary modifications throughout the duration of the disease. The nutritional and metabolic approaches to ALS should start when the diagnosis of ALS is made and should become an integral part of the continuous care to the patient, including nutritional surveillance, dietary counseling, management of dysphagia, and enteral nutrition when needed. Malnutrition and lean body mass loss are frequent findings in ALS patients necessitating comprehensive energy requirement assessment for these patients. Malnutrition is an independent prognostic factor for survival in ALS with a 7.7 fold increase in risk of death. Malnutrition is estimated to develop in one quarter to half of people with ALS (2. Adequate calorie and protein provision would diminish muscle loss in this vulnerable group of patients. Although appropriate amount of energy to be administered is yet to be established, high calorie diet is expected to be effective for potential improvement of survival; ALS patients do not normally receive adequate  intake of energy. A growing number of clinicians suspect that a high calorie diet implemented early in their disease may help people with ALS meet their increased energy needs and extend their survival. Certain high calorie supplements appear to be safe and well tolerated by people with ALS according to studies led by Universitäts klinikum Ulm's and, appear to stabilize body weight within 3 months. In a recent study by Wills et al., intake of high-carbohydrate low-fat supplements has been recommended in ALS patients (3

  1. Control switching in high performance and fault tolerant control

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2010-01-01

    The problem of reliability in high performance control and in fault tolerant control is considered in this paper. A feedback controller architecture for high performance and fault tolerance is considered. The architecture is based on the Youla-Jabr-Bongiorno-Kucera (YJBK) parameterization. By usi...

  2. Advanced ODS FeCrAl alloys for accident-tolerant fuel cladding

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N [ORNL; Unocic, Kinga A [ORNL; Hoelzer, David T [ORNL; Pint, Bruce A [ORNL

    2014-09-01

    ODS FeCrAl alloys are being developed with optimum composition and properties for accident tolerant fuel cladding. Two oxide dispersion strengthened (ODS) Fe-15Cr-5Al+Y2O3 alloys were fabricated by ball milling and extrusion of gas atomized metallic powder mixed with Y2O3 powder. To assess the impact of Mo on the alloy mechanical properties, one alloy contained 1%Mo. The hardness and tensile properties of the two alloys were close and higher than the values reported for fine grain PM2000 alloy. This is likely due to the combination of a very fine grain structure and the presence of nano oxide precipitates. The nano oxide dispersion was however not sufficient to prevent grain boundary sliding at 800 C and the creep properties of the alloys were similar or only slightly superior to fine grain PM2000 alloy. Both alloys formed a protective alumina scale at 1200 C in air and steam and the mass gain curves were similar to curves generated with 12Cr-5Al+Y2O3 (+Hf or Zr) ODS alloys fabricated for a different project. To estimate the maximum temperature limit of use for the two alloys in steam, ramp tests at a rate of 5 C/min were carried out in steam. Like other ODS alloys, the two alloys showed a significant increase of the mas gains at T~ 1380 C compared with ~1480 C for wrought alloys of similar composition. The beneficial effect of Yttrium for wrought FeCrAl does not seem effective for most ODS FeCrAl alloys. Characterization of the hardness of annealed specimens revealed that the microstructure of the two alloys was not stable above 1000 C. Concurrent radiation results suggested that Cr levels <15wt% are desirable and the creep and oxidation results from the 12Cr ODS alloys indicate that a lower Cr, high strength ODS alloy with a higher maximum use temperature could be achieved.

  3. The Alfin-like homeodomain finger protein AL5 suppresses multiple negative factors to confer abiotic stress tolerance in Arabidopsis.

    Science.gov (United States)

    Wei, Wei; Zhang, Yu-Qin; Tao, Jian-Jun; Chen, Hao-Wei; Li, Qing-Tian; Zhang, Wan-Ke; Ma, Biao; Lin, Qing; Zhang, Jin-Song; Chen, Shou-Yi

    2015-03-01

    Plant homeodomain (PHD) finger proteins affect processes of growth and development by changing transcription and reading epigenetic histone modifications, but their functions in abiotic stress responses remain largely unclear. Here we characterized seven Arabidopsis thaliana Alfin1-like PHD finger proteins (ALs) in terms of the responses to abiotic stresses. ALs localized to the nucleus and repressed transcription. Except AL6, all the ALs bound to G-rich elements. Mutations of the amino acids at positions 34 and 35 in AL6 caused loss of ability to bind to G-rich elements. Expression of the AL genes responded differentially to osmotic stress, salt, cold and abscisic acid treatments. AL5-over-expressing plants showed higher tolerance to salt, drought and freezing stress than Col-0. Consistently, al5 mutants showed reduced stress tolerance. We used ChIP-Seq assays to identify eight direct targets of AL5, and found that AL5 binds to the promoter regions of these genes. Knockout mutants of five of these target genes exhibited varying tolerances to stresses. These results indicate that AL5 inhibits multiple signaling pathways to confer stress tolerance. Our study sheds light on mechanisms of AL5-mediated signaling in abiotic stress responses, and provides tools for improvement of stress tolerance in crop plants.

  4. Fabrication and tolerances of optics for high concentration photovoltaics

    OpenAIRE

    Benitez Gimenez, Pablo; Miñano Dominguez, Juan Carlos; Ahmadpanaih, Hamed; Mendes Lopes, Joao; Zamora Herranz, Pablo

    2014-01-01

    High Concentration Photovoltaics (HCPV) require an optical system with high efficiency, low cost and large tolerance. We describe the particularities of the HCPV applications, which constrain the optics design and the manufacturing techonologies.

  5. Analysis of the FeCrAl Accident Tolerant Fuel Concept Benefits during BWR Station Blackout Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Kevin R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    Iron-chromium-aluminum (FeCrAl) alloys are being considered for fuel concepts with enhanced accident tolerance. FeCrAl alloys have very slow oxidation kinetics and good strength at high temperatures. FeCrAl could be used for fuel cladding in light water reactors and/or as channel box material in boiling water reactors (BWRs). To estimate the potential safety gains afforded by the FeCrAl concept, the MELCOR code was used to analyze a range of postulated station blackout severe accident scenarios in a BWR/4 reactor employing FeCrAl. The simulations utilize the most recently known thermophysical properties and oxidation kinetics for FeCrAl. Overall, when compared to the traditional Zircaloy-based cladding and channel box, the FeCrAl concept provides a few extra hours of time for operators to take mitigating actions and/or for evacuations to take place. A coolable core geometry is retained longer, enhancing the ability to stabilize an accident. Finally, due to the slower oxidation kinetics, substantially less hydrogen is generated, and the generation is delayed in time. This decreases the amount of non-condensable gases in containment and the potential for deflagrations to inhibit the accident response.

  6. De Novo Transcriptome Assembly and Identification of Gene Candidates for Rapid Evolution of Soil Al Tolerance in Anthoxanthum odoratum at the Long-Term Park Grass Experiment.

    Directory of Open Access Journals (Sweden)

    Billie Gould

    Full Text Available Studies of adaptation in the wild grass Anthoxanthum odoratum at the Park Grass Experiment (PGE provided one of the earliest examples of rapid evolution in plants. Anthoxanthum has become locally adapted to differences in soil Al toxicity, which have developed there due to soil acidification from long-term experimental fertilizer treatments. In this study, we used transcriptome sequencing to identify Al stress responsive genes in Anthoxanhum and identify candidates among them for further molecular study of rapid Al tolerance evolution at the PGE. We examined the Al content of Anthoxanthum tissues and conducted RNA-sequencing of root tips, the primary site of Al induced damage. We found that despite its high tolerance Anthoxanthum is not an Al accumulating species. Genes similar to those involved in organic acid exudation (TaALMT1, ZmMATE, cell wall modification (OsSTAR1, and internal Al detoxification (OsNRAT1 in cultivated grasses were responsive to Al exposure. Expression of a large suite of novel loci was also triggered by early exposure to Al stress in roots. Three-hundred forty five transcripts were significantly more up- or down-regulated in tolerant vs. sensitive Anthoxanthum genotypes, providing important targets for future study of rapid evolution at the PGE.

  7. Radiation Tolerant, High Capacity Non-Volatile Memory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The need for reliable, high capacity, radiation tolerant nonvolatile memory exists in many Human space flight applications. Most projects rely on COTS hardware for a...

  8. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated by the d...... these alternatives by returning to the notion of tolerance as the endurance of pain, linking this notion to exemplars and theories relevant to the politics of multiculturalism, religious freedom, and free speech....

  9. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated by the d...... these alternatives by returning to the notion of tolerance as the endurance of pain, linking this notion to exemplars and theories relevant to the politics of multiculturalism, religious freedom, and free speech....

  10. Tolerância da cultivar de soja coodetec 201 aos herbicidas inibidores de als Tolerance of the soybean cultivar Coodetec 201 to ALS inhibitor herbicides

    Directory of Open Access Journals (Sweden)

    Aldo Merotto Jr

    2000-01-01

    Full Text Available A obtenção de cultivares resistentes aos herbicidas possibilita o aumento da diversidade dos herbicidas utilizados seletivamente para o controle de plantas daninhas em uma determinada cultura. O aumento da disponibilidade destes herbicidas na cultura da soja pode proporcionar maior facilidade no controle de plantas daninhas de difícil eliminação, de espécies com características biológicas semelhantes à cultura e de plantas daninhas resistentes aos herbicidas. O objetivo deste trabalho foi avaliar a resistência cruzada da cultivar COODETEC 201 a três herbicidas inibidores da ALS, não seletivos para a cultura da soja. O experimento foi realizado em casa de vegetação através da semeadura em vasos, o qual foi disposto em delineamento completamente casualizado em arranjo fatorial. Os tratamentos constaram das cultivares de soja COODETEC 201 e OCEPAR 14 e dos herbicidas imazapyr, metsulfuron e nicosulfuron, aplicados em cinco doses. A aplicação destes produtos foi realizada 30 dias após a emergência, quando as plantas de soja estavam no estádio V4. A área foliar e a fitoxicidade aos 14 e 35 dias após a aplicação do herbicida metsulfuron foram menos afetadas na cultivar COODETEC 201 do que na OCEPAR 14. A determinação da restrição do crescimento das plantas em função da matéria seca das plantas demonstrou que as duas cultivares são igualmente sensíveis ao herbicida imazapyr. A cultivar COODETEC 201 apresentou maior tolerância aos herbicidas metsulfuron e nicosulfuron, sendo 10,25 e 3,25 vezes, respectivamente, mais resistente do que a cultivar OCEPAR 14.Herbicide resistant crops can increase the availability of herbicides for selective use in soybean, can provide weed control of tolerant weed species, weed with identical biological characteristics to the crop, and resitant weeds to herbicides. The objective of this research was to evaluate the cross resitance in the soybean cultivar Coodetec 201 to three ALS inhibitor

  11. A High-Voltage Level Tolerant Transistor Circuit

    NARCIS (Netherlands)

    Annema, Anne Johan; Geelen, Godefridus Johannes Gertrudis Maria

    2001-01-01

    A high-voltage level tolerant transistor circuit, comprising a plurality of cascoded transistors, including a first transistor (T1) operatively connected to a high-voltage level node (3) and a second transistor (T2) operatively connected to a low-voltage level node (2). The first transistor (T1) con

  12. Cold Spray Coating Technique with FeCrAl Alloy Powder for Developing Accident Tolerant Fuel Cladding

    Energy Technology Data Exchange (ETDEWEB)

    Park, Dong Jun; Kim, Hyun Gil; Park, Jeong Yong; Jung, Yang Il; Park, Jung Hwan; Koo, Yang Hyun [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Various approaches to enhance safety have been suggested, replacing current Zr-based alloys for fuel cladding with advanced materials exhibiting lower oxidation rates can be a basic solution. Many advanced materials such as FeCrAl alloys; Mn+1AXn, (MAX) phases, where n = 1 to 3, M is an early transition metal, A is an A-group (mostly IIIA and IVA, or groups 13 and 14) element and X is either carbon or nitrogen; Mo; and SiC are being considered as possible candidates. Among the proposed fuel cladding substitutes, Fe-based alloys are one of the most promising candidates owing to their excellent formability, high strength, and oxidation resistance at high temperature. In this work, the ATF technology concept of Fe-based alloy coating on the existing Zr-alloy cladding was considered and results on the optimization study for fabrication of coated tube samples were described. Result obtained from high temperature oxidation test under steam environment at 1200 .deg. C indicates that FeCrAl alloy coated Zr metal matrix may maintain its integrity during LOCA. This means that accident tolerance of FeCrAl alloy coated Zr cladding sample had been greatly improved compared to that of existing Zr-based alloy fuel cladding.

  13. Fault tolerant highly reliable inertial navigation system

    Science.gov (United States)

    Jeerage, Mahesh; Boettcher, Kevin

    This paper describes a development of failure detection and isolation (FDI) strategies for highly reliable inertial navigation systems. FDI strategies are developed based on the generalized likelihood ratio test (GLRT). A relationship between detection threshold and false alarm rate is developed in terms of the sensor parameters. A new method for correct isolation of failed sensors is presented. Evaluation of FDI performance parameters, such as false alarm rate, wrong isolation probability, and correct isolation probability, are presented. Finally a fault recovery scheme capable of correcting false isolation of good sensors is presented.

  14. Adaptation and survival of plants in high stress habitats via fungal endophyte conferred stress tolerance

    Science.gov (United States)

    Rodriguez, Rusty J.; Woodward, Claire; Redman, Regina S.

    2010-01-01

    From the Arctic to the Antarctic, plants thrive in diverse habitats that impose different levels of adaptive pressures depending on the type and degree of biotic and abiotic stresses inherent to each habitat (Stevens, 1989). At any particular location, the abundance and distribution of individual plant species vary tremendously and is theorized to be based on the ability to tolerate a wide range of edaphic conditions and habitat-specific stresses (Pianka, 1966). The ability of individual plant species to thrive in diverse habitats is commonly referred to as phenotypic plasticity and is thought to involve adaptations based on changes in the plant genome (Givnish, 2002; Pan et al., 2006; Robe and Griffiths, 2000; Schurr et al., 2006). Habitats that impose high levels of abiotic stress are typically colonized with fewer plant species compared to habitats imposing low levels of stress. Moreover, high stress habitats have decreased levels of plant abundance compared to low stress habitats even though these habitats may occur in close proximity to one another (Perelman et al., 2007). This is particularly interesting because all plants are known to perceive, transmit signals, and respond to abiotic stresses such as drought, heat, and salinity (Bartels and Sunkar, 2005; Bohnert et al., 1995). Although there has been extensive research performed to determine the genetic, molecular, and physiological bases of how plants respond to and tolerate stress, the nature of plant adaptation to high stress habitats remains unresolved (Leone et al., 2003; Maggio et al., 2003; Tuberosa et al., 2003). However, recent evidence indicates that a ubiquitous aspect of plant biology (fungal symbiosis) is involved in the adaptation and survival of at least some plants in high stress habitats (Rodriguez et al., 2008).

  15. 荞麦基因型间的耐铝性研究%Research on Al3+ Tolerance among Different Buckwheat Genotypes

    Institute of Scientific and Technical Information of China (English)

    韩承华; 黄凯丰

    2011-01-01

    [目的]筛选出耐铝性较强的荞麦资源.[方法]用水培法对25份荞麦资源的耐铝性进行研究.以发芽的荞麦种子在3 d内的根伸长量衡量耐铝性程度.[结果]低浓度(500 μmol/L以下)的AlCl3处理对荞麦根系的生长具有明显的促进作用,而高浓度(1 000μmol/L)的AlCl3处理则会抑制荞麦根系的生长.荞麦基因型间的耐铝性具有明显差异.[结论]在所选取的25份荞麦材料中,L2081和T442的耐铝胁迫能力最强,值得在荞麦耐铝性育种和耐铝机制的研究中开发利用.%[ Objective ] The research aimed to select the buckwheat accessions with higher Al3+ tolerance. [ Method ] 25 buckwheat accessions were used as materials, the Al3+ tolerance were studied by means of solution culture method in this research. The length of root was used to evaluate the degree of Al3+ tolerance. [ Result] The root growth of some buckwheat accessions were significantly promoted under the concentration of 500 μmol/L, while high concentration of Al3+ ( 1 000 μmol/L) inhibited the buckwheat roots growth. There were great variations of Al3+ tolerance among the different buckwheat genotypes. [ Conclusion] Among the 25 buckwheat genotypes, L2081 and T442 had much higher Al3 + tolerance than the others, which could be used for researching on the buckwheat breeding and the mechanism of the buckwheat Al3+ tolerance.

  16. Neutronic Analysis on Potential Accident Tolerant Fuel-Cladding Combination U3Si2-FeCrAl

    OpenAIRE

    Shengli Chen; Cenxi Yuan

    2017-01-01

    Neutronic performance is investigated for a potential accident tolerant fuel (ATF), which consists of U3Si2 fuel and FeCrAl cladding. In comparison with current UO2-Zr system, FeCrAl has a better oxidation resistance but a larger thermal neutron absorption cross section. U3Si2 has a higher thermal conductivity and a higher uranium density, which can compensate the reactivity suppressed by FeCrAl. Based on neutronic investigations, a possible U3Si2-FeCrAl fuel-cladding system is taken into con...

  17. A high precision radiation-tolerant LVDT conditioning module

    CERN Document Server

    Masi, A; Losito, R; Peronnard, P; Secondo, R; Spiezia, G

    2014-01-01

    Linear variable differential transformer (LVDT) position sensors are widely used in particle accelerators and nuclear plants, thanks to their properties of contact-less sensing, radiation tolerance, infinite resolution, good linearity and cost efficiency. Many applications require high reading accuracy, even in environments with high radiation levels, where the conditioning electronics must be located several hundred meters away from the sensor. Sometimes even at long distances the conditioning module is still exposed to ionizing radiation. Standard off-the-shelf electronic conditioning modules offer limited performances in terms of reading accuracy and long term stability already with short cables. A radiation tolerant stand-alone LVDT conditioning module has been developed using Commercial Off-The-Shelf (COTS) components. The reading of the sensor output voltages is based on a sine-fit algorithm digitally implemented on an FPGA ensuring few micrometers reading accuracy even with low signal-to-noise ratios. ...

  18. Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure

    Science.gov (United States)

    Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.

    2014-05-01

    Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.

  19. 77 FR 27164 - Butylate, Clethodim, Dichlorvos, Dicofol, Isopropyl Carbanilate, et al.; Proposed Tolerance Actions

    Science.gov (United States)

    2012-05-09

    ... the nomenclature of specific tolerances for butylate, methomyl, and tralomethrin, and remove expired... permitted by the tolerance. In addition, EPA is proposing to revise the nomenclature of specific tolerances... May 17, 2011, cease all sales and distribution of dicofol end-use products by October 31, 2013,...

  20. High hydrostatic pressure tolerance of four different anhydrobiotic animal species.

    Science.gov (United States)

    Horikawa, Daiki D; Iwata, Ken-Ichi; Kawai, Kiyoshi; Koseki, Shigenobu; Okuda, Takashi; Yamamoto, Kazutaka

    2009-03-01

    High hydrostatic pressure (HHP) can induce physical changes in DNA, proteins, and lipids, causing lethal or sublethal damage to organisms. However, HHP tolerance of animals has not been studied sufficiently. In this study, HHP tolerance of four species of invertebrate anhydrobiotes (the tardigrade Milnesium tardigradum, a nematode species in the family Plectidae, larvae of Polypedilum vanderplanki, and cysts of Artemia franciscana), which have the potential to enter anhydrobiosis upon desiccation, were investigated by exposing them to 1.2 GPa for 20 minutes. This exposure killed the anhydrobiotes in their ordinary hydrated state, but did not affect their survival in the anhydrobiotic state. The results indicated that the hydrated anhydrobiotes were vulnerable to HHP, but that HHP of 1.2 GPa was not sufficient to kill them in anhyrdobiosis.

  1. Development of Crystal-Tolerant High-Level Waste Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Josef; Vienna, John D.; Schaible, Micah J.; Rodriguez, Carmen P.; Crum, Jarrod V.; Arrigoni, Alyssa L.; Tate, Rachel M.

    2010-12-17

    Twenty five glasses were formulated. They were batched from HLW AZ-101 simulant or raw chemicals and melted and tested with a series of tests to elucidate the effect of spinel-forming components (Ni, Fe, Cr, Mn, and Zn), Al, and noble metals (Rh2O3 and RuO2) on the accumulation rate of spinel crystals in the glass discharge riser of the high-level waste (HLW) melter. In addition, the processing properties of glasses, such as the viscosity and TL, were measured as a function of temperature and composition. Furthermore, the settling of spinel crystals in transparent low-viscosity fluids was studied at room temperature to access the shape factor and hindered settling coefficient of spinel crystals in the Stokes equation. The experimental results suggest that Ni is the most troublesome component of all the studied spinel-forming components producing settling layers of up to 10.5 mm in just 20 days in Ni-rich glasses if noble metals or a higher concentration of Fe was not introduced in the glass. The layer of this thickness can potentially plug the bottom of the riser, preventing glass from being discharged from the melter. The noble metals, Fe, and Al were the components that significantly slowed down or stopped the accumulation of spinel at the bottom. Particles of Rh2O3 and RuO2, hematite and nepheline, acted as nucleation sites significantly increasing the number of crystals and therefore decreasing the average crystal size. The settling rate of ≤10-μm crystal size around the settling velocity of crystals was too low to produce thick layers. The experimental data for the thickness of settled layers in the glasses prepared from AZ-101 simulant were used to build a linear empirical model that can predict crystal accumulation in the riser of the melter as a function of concentration of spinel-forming components in glass. The developed model predicts the thicknesses of accumulated layers quite well, R2 = 0.985, and can be become an efficient tool for the formulation

  2. Tolerance to exercise intensity modulates pleasure when exercising in music: The upsides of acoustic energy for High Tolerant individuals

    Science.gov (United States)

    2017-01-01

    Moderate physical activity can be experienced by some as pleasurable and by others as discouraging. This may be why many people lack sufficient motivation to participate in the recommended 150 minutes of moderately intense exercise per week. In the present study, we assessed how pleasure and enjoyment were modulated differently by one’s tolerance to self-paced physical activity. Sixty-three healthy individuals were allocated to three independent experimental conditions: a resting condition (watching TV), a cycling in silence condition, and a cycling in music condition. The tolerance threshold was assessed using the PRETIE-Questionnaire. Physical activity consisted in cycling during 30 minutes, at an intensity perceived as “somewhat difficult” on the Ratings of Perceived Exertion Scale. While controlling for self-reported physical activity level, results revealed that for the same perception of exertion and a similar level of enjoyment, the High Tolerance group produced more power output than the Low Tolerance group. There was a positive effect of music for High Tolerant individuals only, with music inducing greater power output and more pleasure. There was an effect of music on heart rate frequency in the Low Tolerant individuals without benefits in power output or pleasure. Our results suggest that for Low Tolerant individuals, energizing environments can interfere with the promised (positive) distracting effects of music. Hence, tolerance to physical effort must be taken into account to conceive training sessions that seek to use distracting methods as means to sustain pleasurable exercising over time. PMID:28248980

  3. Tolerance for cougars diminished by high perception of risk

    Directory of Open Access Journals (Sweden)

    Aliah Adams Knopff

    2016-12-01

    Full Text Available In North America, both human and cougar populations are expanding and increasingly sharing the same space, including modified landscapes viewed by people as their "backyard." Low tolerance for cougars in modified landscapes has been identified as a key factor that could restrict continued cougar range expansion in North America, or even reverse some of the gains made by cougar populations in recent decades. To better understand factors influencing tolerance and identify opportunities to improve conservation prospects for cougars, we implemented a questionnaire in west-central Alberta, where both human and cougar populations have increased over the past 20 years and where we had developed a resource selection function for cougars from telemetry data. Respondents overestimated risk from cougars, and more than half believed cougars posed the same or greater risk as driving a car, even though only one Albertan has been killed by a cougar in the last century and hundreds die in car accidents each year. Although respondents valued cougars highly, they indicated that cougars belonged in the wilderness and not near their homes. We predicted that tolerance for cougars would be negatively correlated with increased probability of cougar selection near the respondent's home, but our prediction was not supported. Although such correlations have been reported at broader spatial scales, we suggest they may break down at finer scales. Other factors, such as education, were important drivers of tolerance for cougars in Alberta. Our results suggest that education undertaken to improve large carnivore conservation should focus on accurately defining the risks and ecological benefits resulting from maintaining cougars on the landscape. Education may also need to focus on the importance of nonwilderness habitats (i.e., the rapidly expanding backyard as an important part of long-term conservation and continued range expansion and repatriation of adaptable large

  4. Rub tolerance evaluation of two sintered NiCrAl gas path seal materials. [wear tests of gas turbine engine seals

    Science.gov (United States)

    Bill, R. C.

    1978-01-01

    Two strength level variations of sintered NiCrAl (about 40 percent dense), candidate high pressure turbine seal materials, were subject to rub tolerance testing against AM 355 steel blade tips. The high strength material (17 N/sq mm tensile strength) showed frictional and radial loads that were 20 to 50 percent higher than those measured for the low strength material (15.5 N/ sq mm tensile strength). Measured wear to the AM 355 blade tips was not significantly different for the two sintered NiCrAl seal materials. Wear of the sintered NiCrAl was characterized by material removal to a depth greater than the depth to which blade tips were driven into the seal, indicating self-erosion effects.

  5. Status of FeCrAl ODS Irradiations in the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD)

    2016-08-19

    FeCrAl oxide-dispersion strengthened (ODS) alloys are an attractive sub-set alloy class of the more global FeCrAl material class for nuclear applications due to their high temperature steam oxidation resistance and hypothesized enhanced radiation tolerance. A need currently exists to determine the radiation tolerance of these newly developed alloys. To address this need, a preliminary study was conducted using the High Flux Isotope Reactor (HFIR) to irradiate an early generation FeCrAl ODS alloy, 125YF. Preliminary post-irradiation examination (PIE) on these irradiated specimens have shown good radiation tolerance at elevated temperatures (≥330°C) but possible radiation-induced hardening and embrittlement at irradiations of 200°C to a damage level of 1.9 displacement per atom (dpa). Building on this experience, a new series of irradiations are currently being conceptualized. This irradiation series called the FCAD irradiation program will irradiate the latest generation FeCrAl ODS and FeCr ODS alloys to significantly higher doses. These experiments will provide the necessary information to determine the mechanical performance of irradiated FeCrAl ODS alloys at light water reactor and fast reactor conditions.

  6. Status of FeCrAl ODS Irradiations in the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuel Cycle Research and Development (FCRD)

    2016-08-19

    FeCrAl oxide-dispersion strengthened (ODS) alloys are an attractive sub-set alloy class of the more global FeCrAl material class for nuclear applications due to their high-temperature steam oxidation resistance and hypothesized enhanced radiation tolerance. A need currently exists to determine the radiation tolerance of these newly developed alloys. To address this need, a preliminary study was conducted using the High Flux Isotope Reactor (HFIR) to irradiate an early generation FeCrAl ODS alloy, 125YF. Preliminary post-irradiation examination (PIE) on these irradiated specimens have shown good radiation tolerance at elevated temperatures (≥330°C) but possible radiation-induced hardening and embrittlement at irradiations of 200°C to a damage level of 1.9 displacement per atom (dpa). Building on this experience, a new series of irradiations are currently being conceptualized. This irradiation series called the FCAD irradiation program will irradiate the latest generation FeCrAl ODS and FeCr ODS alloys to significantly higher doses. These experiments will provide the necessary information to determine the mechanical performance of irradiated FeCrAl ODS alloys at light water reactor and fast reactor conditions.

  7. High temperature polymer fuel cells. Heat utilization and co tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Jens, Oluf Jensen; Qingfeng, Li; Ronghuan, He; Gang, Xiao; Ji-An, Gao; Bjerrum, N.J. [Denmark Technical Univ., Department of Chemistry, Lyngby (Denmark)

    2003-09-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer poly-benzimidazole (PBI), which allow working temperatures up to 200 C. The membrane has a water drag number near zero and need no water management at all. The high working temperature allows for utilization of the excess heat for fuel processing. Moreover, it provides an excellent CO tolerance of several percent, and the system needs no purification of hydrogen from a reformer. Continuous service for over 6 months at 150 C has been demonstrated. (authors)

  8. Strong environmental tolerance of Artemia under very high pressure

    Science.gov (United States)

    Minami, K.; Ono, F.; Mori, Y.; Takarabe, K.; Saigusa, M.; Matsushima, Y.; Saini, N. L.; Yamashita, M.

    2010-03-01

    It was shown by the present authors group that a tardigrade in its tun-state can survive after exposed to 7.5 GPa for 13 hours. We have extended this experiment to other tiny animals searching for lives under extreme conditions of high hydrostatic pressure. Artemia, a kind of planktons, in its dried egg-state have strong environmental tolerance. Dozens of Artemia eggs were sealed in a small Teflon capsule together with a liquid pressure medium, and exposed to the high hydrostatic pressure of 7.5 GPa. After the pressure was released, they were soaked in seawater to observe hatching rate. It was proved that 80-90% of the Artemia eggs were alive and hatched into Nauplii after exposed to the maximum pressure of 7.5 GPa for up to 48 hours. Comparing with Tardigrades, Artemia are four-times stronger against high pressure.

  9. Fault tolerant, radiation hard, high performance digital signal processor

    Science.gov (United States)

    Holmann, Edgar; Linscott, Ivan R.; Maurer, Michael J.; Tyler, G. L.; Libby, Vibeke

    1990-01-01

    An architecture has been developed for a high-performance VLSI digital signal processor that is highly reliable, fault-tolerant, and radiation-hard. The signal processor, part of a spacecraft receiver designed to support uplink radio science experiments at the outer planets, organizes the connections between redundant arithmetic resources, register files, and memory through a shuffle exchange communication network. The configuration of the network and the state of the processor resources are all under microprogram control, which both maps the resources according to algorithmic needs and reconfigures the processing should a failure occur. In addition, the microprogram is reloadable through the uplink to accommodate changes in the science objectives throughout the course of the mission. The processor will be implemented with silicon compiler tools, and its design will be verified through silicon compilation simulation at all levels from the resources to full functionality. By blending reconfiguration with redundancy the processor implementation is fault-tolerant and reliable, and possesses the long expected lifetime needed for a spacecraft mission to the outer planets.

  10. Comparative mapping of QTLs for AI tolerance in rice and identification of positional Al-induced genes

    Institute of Scientific and Technical Information of China (English)

    毛传澡; 杨玲; 郑炳松; 吴运荣; 刘非燕; 易可可; 吴平

    2004-01-01

    Aluminum (A1) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an A1 sensitive lowland indica rice variety IR1552 and an A1 tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for A1 tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1,9, 12, respectively, and 1 QTL for root length under A1 stress is identical on chromosome 1 after one week and two weeks stress. Comparison of QTLs on chromosome 1 from different studies indicated an identical interval between C86 and RZ801 with gene(s) for A1 tolerance. This interval provides an important start point for isolating genes responsible for A1 tolerance and understanding the genetic nature of Al tolerance in rice. Four A1 induced ESTs located in this interval were screened by reverse Northern analysis and confirmed by Northern analysis. They would be candidate genes for the QTL.

  11. Overview of lower length scale model development for accident tolerant fuels regarding U3Si2 fuel and FeCrAl cladding

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yongfeng [Idaho National Laboratory

    2016-09-01

    U3Si2 and FeCrAl have been proposed as fuel and cladding concepts, respectively, for accident tolerance fuels with higher tolerance to accident scenarios compared to UO2. However, a lot of key physics and material properties regarding their in-pile performance are yet to be explored. To accelerate the understanding and reduce the cost of experimental studies, multiscale modeling and simulation are used to develop physics-based materials models to assist engineering scale fuel performance modeling. In this report, the lower-length-scale efforts in method and material model development supported by the Accident Tolerance Fuel (ATF) high-impact-problem (HIP) under the NEAMS program are summarized. Significant progresses have been made regarding interatomic potential, phase field models for phase decomposition and gas bubble formation, and thermal conductivity for U3Si2 fuel, and precipitation in FeCrAl cladding. The accomplishments are very useful by providing atomistic and mesoscale tools, improving the current understanding, and delivering engineering scale models for these two ATF concepts.

  12. High Aluminum Tolerance of Rhodotorula sp.RS1 is Associated with Thickening of the Cell Wall Rather than Chelation of Aluminum Ions*1

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; ZHAO Xue-Qiang; T.AIZAWA; M.SUNAIRI; SHEN Ren-Fang

    2013-01-01

    Aluminum (Al) is very toxic to many living organisms,including plants,animals and microorganisms.However,despite many studies on Al tolerance in plants,little has been reported concerning these mechanisms in microorganisms.In this study,a red yeast,which could tolerate Al3+ concentrations as high as 200 mmol L-1,was isolated from acidic soils,identified as Rhodotorula sp.and designated as RS1.As the medium compositions can greatly affect the responses of microorganisms to Al,two culture mediums,glucose medium (GM) and lysogeny broth medium containing soil extract (S-LBM),were used.During growth of RS1,the pH of medium decreased in GM but increased in S-LBM.These changes in the pH of the media were not induced by Al addition.No or little secretion of organic acids was observed in RS1 growth media.Importantly,the thickness of the cell walls and the ratio of cell wall to biomass of RS1 significantly increased in GM with high Al3+ concentrations.In the presence of 100 mmol Al L-1,78.0% of the total Al of whole cells was present in the thickened cell walls.The Al in cell walls was mostly bound to OH,amide and CO groups of polysaccharides.These results suggest that thickening of the cell wall in response to the high Al3+ concentrations may play an important role in the high tolerance of RS1 to Al and that pH increase of the medium and chelation of Al ions are not involved in Al tolerance of this organism.

  13. Preparation and Characterization of Highly Flexible Al2O3/Al/Al2O3 Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Zhijiang Wang

    2015-01-01

    Full Text Available The natural brittleness of oxide ceramics heavily inhibits their more extensive applications. In present research, a highly flexible Al2O3/Al/Al2O3 hybrid composite was fabricated by employing plasma electrolysis oxidation to in situ grow alumina layers on Al foil, in which an outside layer of nanostructured polycrystalline oxide ceramic was composed of nanosized grains with the size of around 17 nm. Due to shear band formation, nanosized circle bubbles prolonging the crack path, grain rotation, and deformation, the fabricated Al2O3/Al/Al2O3 hybrid composite contains no observable cracks even after being bent on a cylindrical bar with a curvature of 1.5 mm. The composite exhibits alumina stiffness at the elastic stage and aluminum ductility during plastic deformation, which provides high flexibility with the well-integrated properties of the components. In a synergistic interaction, the alumina on the outside exhibited a strain of 0.33% at room temperature, which was higher than optimum value of 0.25% presented by reported most flexible oxide ceramics. With the unique characteristics and properties, the Al2O3/Al/Al2O3 composite demonstrates a great potential for various engineering applications.

  14. Coordinated Fault Tolerance for High-Performance Computing

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, Jack; Bosilca, George; et al.

    2013-04-08

    Our work to meet our goal of end-to-end fault tolerance has focused on two areas: (1) improving fault tolerance in various software currently available and widely used throughout the HEC domain and (2) using fault information exchange and coordination to achieve holistic, systemwide fault tolerance and understanding how to design and implement interfaces for integrating fault tolerance features for multiple layers of the software stack—from the application, math libraries, and programming language runtime to other common system software such as jobs schedulers, resource managers, and monitoring tools.

  15. How do yeast cells become tolerant to high ethanol concentrations?

    DEFF Research Database (Denmark)

    Snoek, Tim; Verstrepen, Kevin J.; Voordeckers, Karin

    2016-01-01

    The brewer’s yeast Saccharomyces cerevisiae displays a much higher ethanol tolerance compared to most other organisms, and it is therefore commonly used for the industrial production of bioethanol and alcoholic beverages. However, the genetic determinants underlying this yeast’s exceptional ethanol...... tolerance have proven difficult to elucidate. In this perspective, we discuss how different types of experiments have contributed to our understanding of the toxic effects of ethanol and the mechanisms and complex genetics underlying ethanol tolerance. In a second part, we summarize the different routes...... and challenges involved in obtaining superior industrial yeasts with improved ethanol tolerance....

  16. PRELIMINARY EVALUATION OF FeCrAl CLADDING AND U-Si FUEL FOR ACCIDENT TOLERANT FUEL CONCEPTS

    Energy Technology Data Exchange (ETDEWEB)

    Hales, J. D.; Gamble, K. A.

    2015-09-01

    Since the accident at the Fukushima Daiichi Nuclear Power Station, enhancing the accident tolerance of light water reactors (LWRs) has become an important research topic. In particular, the community is actively developing enhanced fuels and cladding for LWRs to improve safety in the event of accidents in the reactor or spent fuel pools. Fuels with enhanced accident tolerance are those that, in comparison with the standard UO2-zirconium alloy system, can tolerate loss of active cooling in the reactor core for a considerably longer time period during design-basis and beyond design-basis events while maintaining or improving the fuel performance during normal operations and operational transients. This paper presents early work in developing thermal and mechanical models for two materials that may have promise: U-Si for fuel, and FeCrAl for cladding. These materials would not necessarily be used together in the same fuel system, but individually have promising characteristics. BISON, the finite element-based fuel performance code in development at Idaho National Laboratory, was used to compare results from normal operation conditions with Zr-4/UO2 behavior. In addition, sensitivity studies are presented for evaluating the relative importance of material parameters such as ductility and thermal conductivity in FeCrAl and U-Si in order to provide guidance on future experiments for these materials.

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

    Science.gov (United States)

    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 γ-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 γ-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 γ-TiAl, whereas the former can be rationalized by the instability of the microstructure containing metastable phases.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sturm, D; Heilmaier, M; Saage, H [Otto von Guericke University Magdeburg, Institute for Materials and Joining Technology, PO Box 4120, D-39016 Magdeburg (Germany); Aguilar, J; Schmitz, G J; Drevermann, A [ACCESS e.V., Intzestrasse 5, D-52072 Aachen (Germany); Palm, M; Stein, F; Engberding, N [Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Str. 1, D-40237 Duesseldorf (Germany); Kelm, K; Irsen, S, E-mail: daniel.sturm@ovgu.d [Stiftung caesar, Electron Microscopy, Ludwig-Erhard-Allee 2, D-53175 Bonn (Germany)

    2010-07-01

    Compared to Ti-rich {gamma}-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 Al{sub 60}Ti{sub 40} and Al{sub 62}Ti{sub 38} 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 Al{sub 5}Ti{sub 3} and h-Al{sub 2}Ti) and after annealing at 1223 K for 200 h which produced (thermodynamically stable) lamellar {gamma}-TiAl + r-Al{sub 2}Ti microstructures. In general, already the as-cast alloys exhibit a reasonable creep resistance at 1173 K. Compared with Al{sub 60}Ti{sub 40}, both, the as-cast and the annealed Al{sub 62}Ti{sub 38} 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 Al{sub 60}Ti{sub 40} alloy and of Q = 383 kJ/mol for the annealed Al{sub 62}Ti{sub 38} material. The latter coincides well with that of Al diffusion in {gamma}-TiAl, whereas the former can be rationalized by the instability of the microstructure containing metastable phases.

  19. Highly Solvent Tolerance in Serratia marcescens IBBPo15

    Directory of Open Access Journals (Sweden)

    Mihaela Marilena Stancu

    Full Text Available ABSTRACT The aim of this study was to investigate the solvent tolerance mechanisms in Serratia marcescens strain IBBPo15 (KT315653. Serratia marcescens IBBPo15 exhibited remarkable solvent-tolerance, being able to survive in the presence of high concentrations (above 40% of toxic organic solvents, such as cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. S. marcescens IBBPo15 produced extracellular protease and the enzyme production decreased in cells exposed to 5% cyclohexane, n-hexane, toluene, styrene, and ethylbenzene, as compared with the control and n-decane exposed cells. S. marcescens IBBPo15 cells produced carotenoid pigments and alteration of pigments profile (i.e., phytoene, lycopene were observed in cells exposed to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. The exposure of S. marcescens IBBPo15 cells to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, ethylbenzene induced also changes in the intracellular (e.g., 50 kDa protein and extracellular (e.g., 39, 41, 43, 53, 110 kDa proteins proteins profile. Significant RAPD, ARDRA, rep-PCR and PCR pattern modifications were not observed in DNA extracted from S. marcescens IBBPo15 cells exposed to 5% cyclohexane, n-hexane, n-decane, toluene, styrene, and ethylbenzene. Though only HAE1 and acrAB genes were detected in the genome of S. marcescens IBBPo15 cells, the unspecific amplification of other fragments being observed also when the primers for ompF and recA genes were used.

  20. GFOC Project results: High Temperature / High Pressure, Hydrogen Tolerant Optical Fiber

    Energy Technology Data Exchange (ETDEWEB)

    E. Burov; A. Pastouret; E. Aldea; B. Overton; F. Gooijer; A. Bergonzo

    2012-02-12

    Tests results are given for exposure of multimode optical fiber to high temperatures (300 deg. C) and high partial pressure (15 bar) hydrogen. These results demonstrate that fluorine down doped optical fibers are much more hydrogen tolerant than traditional germanium doped multimode optical fibers. Also demonstrated is the similar hydrogen tolerance of carbon coated and non-carbon coated fibers. Model for reversible H2 impact in fiber versus T{sup o}C and H2 pressure is given. These results have significant impact for the longevity of use for distributed temperature sensing applications in harsh environments such as geothermal wells.

  1. InAlN/AlN/GaN heterostructures for high electron mobility transistors

    Science.gov (United States)

    Usov, S. O.; Sakharov, A. V.; Tsatsulnikov, A. F.; Lundin, V. W.; Zavarin, E. E.; Nikolaev, A. E.; Yagovkina, M. A.; Zemlyakov, V. E.; Egorkin, V. I.; Ustinov, V. M.

    2016-08-01

    The results of development of InAlN/AlN/GaN heterostructures, grown on sapphire substrates by metal-organic chemical vapour deposition, and high electron mobility transistors (HEMTs) based on them are presented. The dependencies of the InAlN/AlN/GaN heterostructure properties on epitaxial growth conditions were investigated. The optimal indium content and InAlN barrier layer thicknesses of the heterostructures for HEMT s were determined. The possibility to improve the characteristics of HEMTs by in-situ passivation by Si3N4 thin protective layer deposited in the same epitaxial process was demonstrated. The InAlN/AlN/GaN heterostructure grown on sapphire substrate with diameter of 100 mm were obtained with sufficiently uniform distribution of sheet resistance. The HEMTs with saturation current of 1600 mA/mm and transconductance of 230 mS/mm are demonstrated.

  2. "Tolerating" Adolescent Needs: Moving beyond Zero Tolerance Policies in High School

    Science.gov (United States)

    Gregory, Anne; Cornell, Dewey

    2009-01-01

    The authors contend that zero tolerance discipline policies are inconsistent with adolescent developmental needs for authoritative, as distinguished from authoritarian, discipline. Previous research has applied the notion of authoritative parenting to teaching styles in classrooms, and a similar model of authoritative discipline can guide…

  3. TOLERANCE OF REGIONAL HIGH SCHOOL STUDENTS: ASSESSMENT AND DEVELOPMENT METHODS

    Directory of Open Access Journals (Sweden)

    Elena V. Kalachinskaya

    2015-01-01

    Full Text Available The purpose of the investigation is to define the quality and tolerance level among students; and generalize pedagogical experience of intercultural tolerance formation (as exemplified in Vladivostok State University of Economics and Service.Methods. Theoretical methods of research involve analysis of approaches and results of tolerance among young people; Practical methods – content analysis of the essay content on a given topic, questioning. An empirical case study, described in this article, was carried out by questionnaire survey of 200 VSUES (Vladivostok State University of Economics and Service students from 2–3 courses of various undergraduate training areas.Scientific novelty. The level of students’ tolerant attitude to a series of countries and their residents is specified; combined with the respondents’ knowledge on these countries. Most distinctive students’ views on the «tolerance» concept and reasons for their intolerant behavior are analyzed and presented in this article. Pedagogical and educational technologies used by University for the youth tolerance formation are summarized.Results. Based on the survey, the issues such as limits of applicability of “tolerance” concept in students’ perception, declarative and real tolerance level, and tolerance level to certain countries, as well as in business are investigated. According to the survey, the author makes the conclusion of correlation existence between level of tolerance towards country (nation and level of awareness of it. The author has analysed the students’ essays on tolerance problems; and it was found out that international relations are the most relevant aspect to respondents of tolerant or intolerant behavior. Results of students’ sociological research are compared with results of surveys on similar topics made by All-Russia Public Opinion Research Center and other researchers. Implemented VSUES projects aimed at creating and promoting tolerance

  4. Strong environmental tolerance of moss Venturiella under very high pressure

    Science.gov (United States)

    Ono, F.; Mori, Y.; Takarabe, K.; Nishihira, N.; Shindo, A.; Saigusa, M.; Matsushima, Y.; Saini, N. L.; Yamashita, M.

    2010-03-01

    It was shown by the present authors group that tardigrade can survive under high pressure of 7.5 GPa. In the case of land plants, however, no result of such experiment has been reported. We have extended our experiments to moss searching for lives under very high pressure. Spore placentas of moss Venturiella were sealed in a small Teflon capsule together with a liquid pressure medium. The capsule was put in the center of a pyrophillite cube, and the maximum pressure of 7.5 GPa was applied using a two-stage cubic anvil press. The pressure was kept constant at the maximum pressure for12, 24, 72 and 144 hours. After the pressure was released, the spores were seeded on a ager medium, and incubated for one week and more longer at 25°C with white light of 2000 lux. It was proved that 70-90% of the spores were alive and germinated after exposed to the maximum pressure of 7.5 GPa for up to 72 hours. However, after exposed to 7.5 GPa for 6 days, only 4 individuals in a hundred were germinated. The pressure tolerance of moss Venturiella is found to be stronger than a small animal, tardigrade.

  5. Strong environmental tolerance of moss Venturiella under very high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ono, F; Mori, Y; Takarabe, K [Department of Applied Science, Okayama University of Science, 1-1 Ridaicho, Okayama 700-0005 (Japan); Nishihira, N; Shindo, A [Okayama Ichinomiya High School, Okayama 700-0005 (Japan); Saigusa, M [Department of Biology, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Matsushima, Y [Department of Physics, Okayama University, 3-1-1 Tsushima-Naka, Okayama 700-8530 (Japan); Saini, N L [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , Piazzale Aldo Moro 2, 00185 Rome (Italy); Yamashita, M, E-mail: fumihisa@das.ous.ac.j [Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)

    2010-03-01

    It was shown by the present authors group that tardigrade can survive under high pressure of 7.5 GPa. In the case of land plants, however, no result of such experiment has been reported. We have extended our experiments to moss searching for lives under very high pressure. Spore placentas of moss Venturiella were sealed in a small Teflon capsule together with a liquid pressure medium. The capsule was put in the center of a pyrophillite cube, and the maximum pressure of 7.5 GPa was applied using a two-stage cubic anvil press. The pressure was kept constant at the maximum pressure for12, 24, 72 and 144 hours. After the pressure was released, the spores were seeded on a ager medium, and incubated for one week and more longer at 25{sup 0}C with white light of 2000 lux. It was proved that 70-90% of the spores were alive and germinated after exposed to the maximum pressure of 7.5 GPa for up to 72 hours. However, after exposed to 7.5 GPa for 6 days, only 4 individuals in a hundred were germinated. The pressure tolerance of moss Venturiella is found to be stronger than a small animal, tardigrade.

  6. Increased nicotianamine biosynthesis confers enhanced tolerance of high levels of metals, in particular nickel, to plants

    National Research Council Canada - National Science Library

    Kim, Suyeon; Takahashi, Michiko; Higuchi, Kyoko; Tsunoda, Kyoko; Nakanishi, Hiromi; Yoshimura, Etsuro; Mori, Satoshi; Nishizawa, Naoko K

    2005-01-01

    .... Nicotianamine synthase overexpression resulted in increased biosynthesis of nicotianamine in transgenic plants, which conferred enhanced tolerance of high levels of metals, particularly nickel, to plants...

  7. Urban physiology: city ants possess high heat tolerance.

    Directory of Open Access Journals (Sweden)

    Michael J Angilletta

    Full Text Available Urbanization has caused regional increases in temperature that exceed those measured on a global scale, leading to urban heat islands as much as 12 degrees C hotter than their surroundings. Optimality models predict ectotherms in urban areas should tolerate heat better and cold worse than ectotherms in rural areas. We tested these predications by measuring heat and cold tolerances of leaf-cutter ants from South America's largest city (São Paulo, Brazil. Specifically, we compared thermal tolerances of ants from inside and outside of the city. Knock-down resistance and chill-coma recovery were used as indicators of heat and cold tolerances, respectively. Ants from within the city took 20% longer to lose mobility at 42 degrees C than ants from outside the city. Interestingly, greater heat tolerance came at no obvious expense of cold tolerance; hence, our observations only partially support current theory. Our results indicate that thermal tolerances of some organisms can respond to rapid changes in climate. Predictive models should account for acclimatory and evolutionary responses during climate change.

  8. Neutronic Analysis on Potential Accident Tolerant Fuel-Cladding Combination U3Si2-FeCrAl

    Directory of Open Access Journals (Sweden)

    Shengli Chen

    2017-01-01

    Full Text Available Neutronic performance is investigated for a potential accident tolerant fuel (ATF, which consists of U3Si2 fuel and FeCrAl cladding. In comparison with current UO2-Zr system, FeCrAl has a better oxidation resistance but a larger thermal neutron absorption cross section. U3Si2 has a higher thermal conductivity and a higher uranium density, which can compensate the reactivity suppressed by FeCrAl. Based on neutronic investigations, a possible U3Si2-FeCrAl fuel-cladding system is taken into consideration. Fundamental properties of the suggested fuel-cladding combination are investigated in a fuel assembly. These properties include moderator and fuel temperature coefficients, control rods worth, radial power distribution (in a fuel rod, and different void reactivity coefficients. The present work proves that the new combination has less reactivity variation during its service lifetime. Although, compared with the current system, it has a little larger deviation on power distribution and a little less negative temperature coefficient and void reactivity coefficient and its control rods worth is less important, variations of these parameters are less important during the service lifetime of fuel. Hence, U3Si2-FeCrAl system is a potential ATF candidate from a neutronic view.

  9. Optical glass with tightest refractive index and dispersion tolerances for high-end optical designs

    Science.gov (United States)

    Jedamzik, R.; Reichel, S.; Hartmann, P.

    2014-03-01

    In high end optical designs the quality of the optical system not only depends on the chosen optical glasses but also on the available refractive index and Abbe number tolerances. The primary optical design is based on datasheet values of the refractive index and Abbe number. In general the optical position of the delivered glass will deviate from the catalog values by given tolerances due to production tolerances. Therefore in many cases the final optical design needs to be modified based on real glass data. Tighter refractive index and Abbe number tolerances can greatly reduce this additional amount of work. The refractive index and Abbe number of an optical glass is a function of the chemical composition and the annealing process. Tight refractive index tolerances require not only a close control and high reliability of the melting and fine annealing process but also best possible material data. These data rely on high accuracy measurement and accurate control during mass production. Modern melting and annealing procedure do not only enable tight index tolerances but also a high homogeneity of the optical properties. Recently SCHOTT was able to introduce the tightest available refractive index and Abbe number tolerance available in the market: step 0.5 meaning a refractive index tolerance of +/- 0.0001 and an Abbe number tolerance of +/- 0.1%. This presentation describes how the refractive index depends on the glass composition and annealing process and describes the requirements to get to this tightest refractive index and Abbe number tolerance.

  10. 77 FR 59120 - Butylate, Clethodim, Dichlorvos, Dicofol, Isopropyl Carbanilate, et al.; Tolerance Actions

    Science.gov (United States)

    2012-09-26

    ... as India, China, and Argentina, and requested that EPA not revoke the dicofol tolerances on tea but.../16 Chestnut 0.1 10/31/16 Citrus, dried pulp 12.0 10/31/16 Citrus oil 200.0 10/31/16 Cotton, refined oil 0.5 10/31/16 Cotton, undelinted seed 0.1 10/31/16 Fruit, citrus, group 10 6.0 10/31/16 Fruit,...

  11. Effect of Mg$^{2+}$ ions co-doping on timing performance and radiation tolerance of Cerium doped Gd$_{3}$Al$_{2}$Ga$_{3}$O$_{12}$ crystals

    CERN Document Server

    Lucchini, M.T.; Bohacek, P.; Gundacker, S.; Kamada, K.; Nikl, M.; Petrosyan, A.; Yoshikawa, A.; Auffray, E.

    2016-01-01

    Inorganic scintillators with high density and high light yield are of major interest for applications in medical imaging and high energy physics detectors. In this work, the optical and scintillation properties of Mg co-doped Ce:Gd3Al2Ga3O12 crystals, grown using Czochralski technique, have been investigated and compared with Ce:Gd3Al2Ga3O12 ones prepared with identical technology. Improvements in the timing performance of the Mg co-doped samples with respect to Ce:Gd3Al2Ga3O12 ones have been measured, namely a substantial shortening of the rise time and scintillation decay components and lower afterglow were achieved. In particular, a significantly better coincidence time resolution of 233 ps FWHM, being a fundamental parameter for TOF-PET devices, has been observed in Mg co-doped crystals. The samples have also shown a good radiation tolerance under high doses of γ-rays, making them suitable candidates for applications in harsh radiation environments, such as detectors at future collider experiments.

  12. Starvation, together with the SOS response, mediates high biofilm-specific tolerance to the fluoroquinolone ofloxacin.

    Directory of Open Access Journals (Sweden)

    Steve P Bernier

    Full Text Available High levels of antibiotic tolerance are a hallmark of bacterial biofilms. In contrast to well-characterized inherited antibiotic resistance, molecular mechanisms leading to reversible and transient antibiotic tolerance displayed by biofilm bacteria are still poorly understood. The physiological heterogeneity of biofilms influences the formation of transient specialized subpopulations that may be more tolerant to antibiotics. In this study, we used random transposon mutagenesis to identify biofilm-specific tolerant mutants normally exhibited by subpopulations located in specialized niches of heterogeneous biofilms. Using Escherichia coli as a model organism, we demonstrated, through identification of amino acid auxotroph mutants, that starved biofilms exhibited significantly greater tolerance towards fluoroquinolone ofloxacin than their planktonic counterparts. We demonstrated that the biofilm-associated tolerance to ofloxacin was fully dependent on a functional SOS response upon starvation to both amino acids and carbon source and partially dependent on the stringent response upon leucine starvation. However, the biofilm-specific ofloxacin increased tolerance did not involve any of the SOS-induced toxin-antitoxin systems previously associated with formation of highly tolerant persisters. We further demonstrated that ofloxacin tolerance was induced as a function of biofilm age, which was dependent on the SOS response. Our results therefore show that the SOS stress response induced in heterogeneous and nutrient-deprived biofilm microenvironments is a molecular mechanism leading to biofilm-specific high tolerance to the fluoroquinolone ofloxacin.

  13. Preliminary Results on FeCrAl Alloys in the As-received and Welded State Designed to Have Enhanced Weldability and Radiation Tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gussev, Maxim N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hu, Xunxiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-30

    The present report summarizes and discusses the recent results on developing a modern, nuclear grade FeCrAl alloy designed to have enhanced radiation tolerance and weldability. The alloys used for these investigations are modern FeCrAl alloys based on a Fe-13Cr-5Al-2Mo-0.2Si-0.05Y alloy (in wt.%, designated C35M). Development efforts have focused on assessing the influence of chemistry and microstructure on the fabricability and performance of these newly developed alloys. Specific focus was made to assess the weldability, thermal stability, and radiation tolerance.

  14. High quality UV AlGaN/AlGaN distributed Bragg reflectors and microcavities

    Science.gov (United States)

    Mitrofanov, Oleg; Schmult, S.; Manfra, M. J.; Siegrist, T.; Weimann, N. G.; Sergent, A. M.; Molnar, R. J.

    2007-02-01

    We demonstrate high-reflectivity crack-free Al 0.18Ga 0.82N/Al 0.8Ga 0.2N distributed Bragg reflectors (DBR) and monolithic microcavities grown by molecular beam epitaxy on thick c-axis GaN templates. The elastic strain energy in the epilayer is minimized by compensating the compressive and tensile stress in every period of the DBR structure. A 25 period DBR mirror provides a 26nm-wide stop band centered at 347 nm with the maximum reflectivity higher than 99%. The high-reflectivity DBRs can be used to form high Q-factor monolithic AlGaN/AlGaN microcavities.

  15. Physical and chemical performances of high Al steels

    Institute of Scientific and Technical Information of China (English)

    WANG Hai-chuan; DONG Yuan-chi; ZHANG Wen-ming; WANG Shi-jun; ZHOU Yun

    2005-01-01

    The effects of acid-soluble Al content on the physical and chemical performances of high Al steels were investigated. The results show that the distribution of acid-soluble Al in steel substrate is uniform. With increasing Al content, the strength and toughness of steels decrease a little but the hardness increases. The average yield strength and tensile strength are 425 MPa and 570 MPa, respectively, and the Rockwell hardness is 89.7. For non-Al steels the average oxidation rate is up to 0.421 mg/(cm2·h) at 1 373 K. For high Al steels, when the mass fraction of Al is less than 5%, there is a thinner gray oxidized layer on surface and the oxidation rate is high; when the mass fraction of Al is more than 8.0%, the thin, close and yellow glossing film still exists, and the average oxidation rate is only 0.016 mg/(cm2·h).

  16. Fabrication of high-quality submicron Nb/Al-AlOx/Nb tunnel junctions

    Institute of Scientific and Technical Information of China (English)

    Yu Hai-Feng; Cao Wen-Hui; Zhu Xiao-Bo; Yang Hai-Fang; Yu Hong-Wei; Ren Yu-Feng; Gu Chang-Zhi; Chen Geng-Hua; Zhao Shi-Ping

    2008-01-01

    Nb/Al-AlOx/Nb tunnel junctions are often used in the studies of macroscopic quantum phenomena and supercon-ducting qubit applications of the Josepheon devices. In this work, we describe a convenient and reliable process using electron beam lithography for the fabrication of high-quality, submicron-sized Nb/Al-AlOx/Nb Josephson junctions.The technique follows the well-known selective Nb etching process and produces high-quality junctions with Vm=100 mV at 2.3 K for the typical critical current density of 2.2 kA/cm2, which can be adjusted by controlling the oxygen pressure and oxidation time during the formation of the tunnelling barrier. We present the results of the temperature depen-dence of the sub-gap current and in-plane magnetic-field dependence of the critical current, and compare them with the theoretical predictions.

  17. Lygus hesperus (Heteroptera: Miridae) tolerates high concentrations of dietary nickel

    Institute of Scientific and Technical Information of China (English)

    ROBERT S. BOYD

    2007-01-01

    Nickel hyperaccumulator plants contain unusually elevated levels of Ni (> 1 000 μg Ni/g). Some insect herbivores, including Lygus hesperus (Western tarnished plant bug), have been observed feeding on the California Ni hyperaccumulator Streptanthus polygaloides. This bug may be able to utilize S. polygaloides as a host either through its feeding behavior or by physiological tolerance of Ni. This experiment determined the Ni tolerance of L. hesperus by offering insects artificial diet amended with 0,0.4, 1, 2, 4.5,10, 20 and 40 mmol Ni/L and recording survival. Survival varied due to Ni concentration, with diets containing 10 mmol Ni/L and greater resulting in significantly lower survival compared to the control (0 mmol Ni/L) treatment. Insects tolerated diet containing as much as 4.5 mmol Ni/L, a relatively elevated Ni concentration. I conclude that L. hesperus can feed on S. polygaloides because it is Ni-tolerant, probably due to physiological mechanisms that provide it with resistance to plant chemical defenses including elemental defenses such as hyperaccumulated Ni.

  18. Genetic Dissection High Temperature Tolerance Traits in Maize-a QTL Mapping Approach

    Science.gov (United States)

    High temperature (HT) stress severely limits plant productivity and causes extensive economic loss to US agriculture. Understanding HT adaptation mechanisms in crop plants is crucial to the success of developing HT tolerant varieties. Maize inbred lines vary greatly in HT tolerance based on field ...

  19. The high tolerance to aluminium in crucian carp (Carassius carassius) is associated with its ability to avoid hypoxia.

    Science.gov (United States)

    Poléo, Antonio B S; Schjolden, Joachim; Sørensen, Jørgen; Nilsson, Göran E

    2017-01-01

    It is well known that aluminium is the principle toxicant killing fish in acidified freshwater systems, and it has been shown that crucian carp (Carassius carassius) can survive exposures to aqueous aluminium levels toxic to most other freshwater fish species. The crucian carp has a remarkable ability to survive anoxic conditions, and the aim of the present study was to reveal if the tolerance to aluminium can be associated with the ability to survive prolonged anoxia. Crucian carps were exposed to either acidic Al-rich water (pH 5.8; 960 μg Al/l), acidic Al-poor water (pH 5.8; 50 μg Al/l) or untreated control water (pH 6.5; 50 μg Al/l). Blood, muscle and gill samples were collected from exposed fish, and closed respirometry was performed to measure critical O2-tension an normoxic O2-consumption. The results show an increased gill surface area in Al-exposed fish, while the critical O2-tension did not change. The normoxic O2-consumption was lower in Al-exposed fish and might be due to a reduced metabolic rate. The results suggest that crucian carp exposed to aluminium do not become hypoxic, since haematocrit, plasma lactate and blood ethanol did not differ from that of control fish after 14 days of exposure. We also observed an initial loss of plasma chloride and sodium, followed by a stabilisation of these ions at a lower level than in control fish. The decrease in plasma ions caused a transient increase in haematocrit and water content in muscle tissue, returning to control levels when the ion concentrations stabilised, suggesting that the water balance was restored. We conclude that the high tolerance to aluminium in crucian carp is associated with its ability to avoid hypoxia as well as an ability to counteract a continuous loss of plasma ions.

  20. High temperature oxidation of beta-NiAl

    Science.gov (United States)

    Koychak, J. K.; Mitchell, T. E.; Smialek, J. L.

    1985-01-01

    The oxidation of single crystal beta-NiAl has been studied primarily using electron microscopy. Oriented metastable Al2O3 phases form during transient oxidation at 800 C. Specific orientation relationships exist on all metal orientations studied and are a result of the small mismatch along aligned close-packed directions in the cation sublattices of the metal and oxide. Transformation of the metastable Al2O3 phases at 1100 C results in an oxide morphology described as the 'lacey' structure of alpha-Al2O3 scales. This structure results from impingement of oriented patches of alpha-Al2O3 as the transformation initiates and moves radially parallel to the surface. Scale growth occurs by diffusion along high angle grain boundaries. A drastic reduction in oxidation rate accompanies the change in oxide morphology.

  1. Las fronteras de la violencia cultural: del estigma tolerable al estigma intolerable

    OpenAIRE

    Nelson Arteaga Botello; Cristina Dyjak Montes de Oca

    2006-01-01

    El presente documento tiene por objetivo, con base en un estudio de caso en escuelas de educación básica, mostrar cómo se cristaliza la violencia cultural hacia niños invidentes. Dicha cristalización pasa por dos referentes de interacción y relación social al interior del espacio escolar. El primero está constituido por parámetros de normalidad y anormalidad a partir de la localización de estigmas. El segundo se encuentra, a contrapelo de la tendencia anterior, tratando de diluir los efectos ...

  2. Highly strained AlAs-type interfaces in InAs/AlSb heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Vallet, M., E-mail: maxime.vallet@cemes.fr; Warot-Fonrose, B.; Gatel, C.; Nicolai, J.; Ponchet, A. [CEMES CNRS-UPR 8011, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse (France); Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS-Universidad de Zaragoza, Toulouse (France); Claveau, Y.; Combe, N. [CEMES CNRS-UPR 8011, Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse (France); Magen, C. [Transpyrenean Associated Laboratory for Electron Microscopy (TALEM), CEMES-INA, CNRS-Universidad de Zaragoza, Toulouse (France); Laboratorio de Microscopias Avanzadas (LMA), Instituto de Nanociencia de Aragon (INA)—ARAID and Departamento de Fisica de la Materia Condensada, Universidad de Zaragoza, 50018 Zaragoza (Spain); Teissier, R.; Baranov, A. N. [Institute of Electronics and Systems, UMR 5214 CNRS – University of Montpellier, 34095 Montpellier (France)

    2016-05-23

    Spontaneously formed Al-As type interfaces of the InAs/AlSb system grown by molecular beam epitaxy for quantum cascade lasers were investigated by atomic resolution scanning transmission electron microscopy. Experimental strain profiles were compared to those coming from a model structure. High negative out-of-plane strains with the same order of magnitude as perfect Al-As interfaces were observed. The effects of the geometrical phase analysis used for strain determination were evidenced and discussed in the case of abrupt and huge variations of both atomic composition and bond length as observed in these interfaces. Intensity profiles performed on the same images confirmed that changes of chemical composition are the source of high strain fields at interfaces. The results show that spontaneously assembled interfaces are not perfect but extend over 2 or 3 monolayers.

  3. High-throughput phenotyping to detect drought tolerance QTL in wild barley introgression lines

    KAUST Repository

    Honsdorf, Nora

    2014-05-13

    Drought is one of the most severe stresses, endangering crop yields worldwide. In order to select drought tolerant genotypes, access to exotic germplasm and efficient phenotyping protocols are needed. In this study the high-throughput phenotyping platform "The Plant Accelerator", Adelaide, Australia, was used to screen a set of 47 juvenile (six week old) wild barley introgression lines (S42ILs) for drought stress responses. The kinetics of growth development was evaluated under early drought stress and well watered treatments. High correlation (r = 0.98) between image based biomass estimates and actual biomass was demonstrated, and the suitability of the system to accurately and non-destructively estimate biomass was validated. Subsequently, quantitative trait loci (QTL) were located, which contributed to the genetic control of growth under drought stress. In total, 44 QTL for eleven out of 14 investigated traits were mapped, which for example controlled growth rate and water use efficiency. The correspondence of those QTL with QTL previously identified in field trials is shown. For instance, six out of eight QTL controlling plant height were also found in previous field and glasshouse studies with the same introgression lines. This indicates that phenotyping juvenile plants may assist in predicting adult plant performance. In addition, favorable wild barley alleles for growth and biomass parameters were detected, for instance, a QTL that increased biomass by approximately 36%. In particular, introgression line S42IL-121 revealed improved growth under drought stress compared to the control Scarlett. The introgression line showed a similar behavior in previous field experiments, indicating that S42IL-121 may be an attractive donor for breeding of drought tolerant barley cultivars. © 2014 Honsdorf et al.

  4. A Novel TiNi/AlSi Composite with High Strength and High Damping Capacity

    Institute of Scientific and Technical Information of China (English)

    Shuwei LIU; Xiuyan LI; Desheng YAN; Haichang JIANG; Lijian RONG

    2008-01-01

    A novel TiNi/AlSi composite with high compressive strength and high damping capacity was obtained by infiltrating Al-12%Si alloy into porous TiNi alloy.It had been found that the high compressive strength (440 MPa) of TiNi/AlSi composite is due to the increase of effective carrying area after infiltrating Al-12%Si alloy,while the high damping capacity is contributed to TiNi carcass,Al-12%Si filling material and micro-slipping at the interface.

  5. τ-MnAl with high coercivity and saturation magnetization

    Directory of Open Access Journals (Sweden)

    J. Z. Wei

    2014-12-01

    Full Text Available In this paper, high purity τ-Mn54Al46 and Mn54−xAl46Cxalloys were successfully prepared using conventional arc-melting, melt-spinning, and heat treatment process. The magnetic and the structural properties were examined using x-ray diffraction (XRD, powder neutron diffraction and magnetic measurements. A room temperature saturation magnetization of 650.5 kAm-1, coercivity of 0.5 T, and a maximum energy product of (BHmax = 24.7 kJm-3 were achieved for the pure Mn54Al46 powders without carbon doping. The carbon substituted Mn54−xAl46Cx, however, reveals a lower Curie temperature but similar saturation magnetization as compared to the carbon-free sample. The electronic structure of MnAl shows that the Mn atom possesses a magnetic moment of 2.454 μB which results from strong hybridization between Mn-Al and Mn-Mn. We also investigated the volume and c/a ratio dependence of the magnetic moments of Mn and Al. The results indicate that an increase in the intra-atomic exchange splitting due to the cell volume expansion, leads to a large magnetic moment for the Mn atom. The Mn magnetic moment can reach a value of 2.9 μB at a volume expansion rate of ΔV/V ≈ 20%.

  6. Overexpression of a modiifed AM79 aroA gene in transgenic maize confers high tolerance to glyphosate

    Institute of Scientific and Technical Information of China (English)

    REN Zhen-jing; CAO Gao-yi; ZHANG Yu-wen; LIU Yan; LIU Yun-jun

    2015-01-01

    It has previously been shown that a bacterial 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) encoding gene AM79 aroA can be a candidate gene to develop glyphosate-tolerant transgenic crops (Cao et al. 2012). In this study, AM79 aroA was redesigned using the plant biased codons and eliminating the motifs which would lead to the instability of mRNA, to create a synthetic gene that would be expressed highly in plant cel s. The redesigned and artiifcial y synthesized gene, named as mAM79, was cloned into plant expression vector pM3301UbiSpAM79, where mAM79 is fused with signal peptide sequence of pea rib-1,5-bisphospate carboxylase (rbcS) smal subunit and control ed by ubiquitin promoter. The plasmid was transformed into maize (Zea mays) immature embryos using Agrobacterium-mediated transformation method. Total 74 regenerated plants were obtained and PCR analysis showed that these transgenic plants had the integration of mAM79. Southern blot analysis was performed on the genomic DNA from four transgenic lines, and the result showed that one or two copies of mAM79 were integrated into maize genome. RT-PCR analysis result indicated that mAM79 was highly transcribed in transgenic maize plants. When sprayed with glyphosate, transgenic maize line AM85 and AM72 could tolerate 4-fold of commercial usage of glyphosate;however, al the non-transgenic maize plants were kil ed by glyphosate. The results in this study conifrmed that mAM79 could be used to develop glyphosate-tolerant maize, and the obtained transgenic maize lines could be used for the breeding of glyphosate-tolerant maize.

  7. Leaf ontogeny strongly influences photosynthetic tolerance to drought and high temperature in Gossypium hirsutum

    Science.gov (United States)

    Temperature and drought are major abiotic limitations to crop productivity worldwide. While abiotic stress physiology research has focused primarily on fully expanded leaves, no studies have investigated photosynthetic tolerance to concurrent drought and high temperature during leaf ontogeny. To add...

  8. Tolerância à dor no infarto do miocárdio Tolerancia al dolor en infarto del miocárdio Pain tolerance during myocardium infarction

    Directory of Open Access Journals (Sweden)

    Fernanda Carneiro Mussi

    2010-01-01

    Full Text Available OBJETIVO: Analisar a tolerância à dor como sintoma prodrômico do infarto do miocárdio na perspectiva dos gêneros masculino e feminino em pacientes que vivenciaram esse evento cardiovascular. MÉTODOS: Estudo exploratório de natureza quanti-qualitativa. Entrevistou-se 43 mulheres e 54 homens em hospital público. Os dados sóciodemográficos foram analisados em percentuais e os qualitativos com base na análise de conteúdo e da categoria gênero. RESULTADOS: A mediana de idade para homens foi 55,3 e mulheres de 61,5 anos. Predominou para os gêneros a baixa escolaridade e inatividade profissional. Os homens tinham renda familiar maior e viviam mais em companhia de alguém. Evidenciou-se que homens e mulheres demonstraram igualmente enfrentamento e resistência à dor, visando manter o controle da própria existência e reproduzindo construções sociais sobre o masculino e o feminino em suas vidas cotidianas. CONCLUSÃO: O desafio profissional é atuar no plano simbólico dos gêneros para reduzir o retardo na decisão de buscar atenção médica e possibilitar os benefícios imediatos das terapias de reperfusão coronária.OBJETIVO: Analizar la tolerancia al dolor como síntoma prodrómico del infarto del miocardio en la perspectiva de los géneros masculino y femenino en pacientes que experimentaron ese evento cardiovascular. MÉTODOS: Estudio exploratorio de naturaleza cuantitativa cualitativa. Se entrevistaron 43 mujeres y 54 hombres en un hospital público. Los datos sociodemográficos fueron analizados en porcentajes y los cualitativos con base en el análisis de contenido y de la categoría género. RESULTADOS: El promedio de edad para hombres fue 55,3 y mujeres de 61,5 años. Predominó para los dos géneros la baja escolaridad e inactividad profesional. Los hombres tenían renta familiar mayor y vivían más en compañía de alguien. Se evidenció que los hombres y mujeres demostraron igualmente enfrentamiento y resistencia al

  9. High operating temperature InAlSb infrared detectors

    Science.gov (United States)

    Li, Mo; Chen, Gang; Li, Hao; Zhang, Zhaofan; Peng, Pan; Lv, Yanqiu

    2016-10-01

    The recent progresses of our research in InxAl1-xSb infrared detector based on molecular beam epitaxy are presented. Al composition with 0-0.3 is used for adjusting energy gaps of InSb and a p-i-n structure is utilized to decrease dark current. InxAl1-xSb ternary alloys are grown by molecular beam epitaxy on InSb substrates, and the material quality is characterized using high resolution x-ray diffraction. In order to exploit this epitaxial material we have developed new mesa and passivation technology based on matured InSb fabrication process. The InAlSb diodes has a cut-off wavelength of around 4.8μm. The reverse bias dark current of InAlSb diodes have been measured. The dark current of the pin InAlSb diode is seen to smaller that of the bulk p+n InSb diodes by 4-5 times in 77K.

  10. The high-pressure phase of CePtAl

    Energy Technology Data Exchange (ETDEWEB)

    Heymann, Gunter [Univ. Innsbruck (Austria). Inst. fuer Allgemeine, Anorganische und Theoretische Chemie; Heying, Birgit; Rodewald, Ute C. [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Janka, Oliver [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie; Univ. Oldenburg (Germany). Inst. fuer Chemie

    2017-03-01

    The intermetallic aluminum compound HP-CePtAl was synthesized by arc melting of the elements with subsequent high-pressure/high-temperature treatment at 1620 K and 10.5 GPa in a multianvil press. The compound crystallizes in the hexagonal MgZn{sub 2}-type structure (P6{sub 3}/mmc) with lattice parameters of a=552.7(1) and c=898.8(2) pm refined from powder X-ray diffraction data. With the help of single crystal investigations (wR=0.0527, 187 F{sup 2} values, 13 variables), the proposed structure type was confirmed and the mixed Pt/Al site occupations could be refined. Magnetic susceptibility measurements showed a disappearance of the complex magnetic ordering phenomena, which are observed in NP-CePtAl.

  11. A novel 5-enolpyruvylshikimate-3-phosphate synthase shows high glyphosate tolerance in Escherichia coli and tobacco plants

    National Research Council Canada - National Science Library

    Cao, Gaoyi; Liu, Yunjun; Zhang, Shengxue; Yang, Xuewen; Chen, Rongrong; Zhang, Yuwen; Lu, Wei; Liu, Yan; Wang, Jianhua; Lin, Min; Wang, Guoying

    2012-01-01

    ...) is the primary target of the broad-spectrum herbicide glyphosate. Identification of new aroA genes coding for EPSPS with a high level of glyphosate tolerance is essential for the development of glyphosate-tolerant crops...

  12. An Integrated Fault Tolerant Robotic Controller System for High Reliability and Safety

    Science.gov (United States)

    Marzwell, Neville I.; Tso, Kam S.; Hecht, Myron

    1994-01-01

    This paper describes the concepts and features of a fault-tolerant intelligent robotic control system being developed for applications that require high dependability (reliability, availability, and safety). The system consists of two major elements: a fault-tolerant controller and an operator workstation. The fault-tolerant controller uses a strategy which allows for detection and recovery of hardware, operating system, and application software failures.The fault-tolerant controller can be used by itself in a wide variety of applications in industry, process control, and communications. The controller in combination with the operator workstation can be applied to robotic applications such as spaceborne extravehicular activities, hazardous materials handling, inspection and maintenance of high value items (e.g., space vehicles, reactor internals, or aircraft), medicine, and other tasks where a robot system failure poses a significant risk to life or property.

  13. Rad-Tolerant, Thermally Stable, High-Speed Fiber-Optic Network for Harsh Environments

    Science.gov (United States)

    Leftwich, Matt; Hull, Tony; Leary, Michael; Leftwich, Marcus

    2013-01-01

    Future NASA destinations will be challenging to get to, have extreme environmental conditions, and may present difficulty in retrieving a spacecraft or its data. Space Photonics is developing a radiation-tolerant (rad-tolerant), high-speed, multi-channel fiber-optic transceiver, associated reconfigurable intelligent node communications architecture, and supporting hardware for intravehicular and ground-based optical networking applications. Data rates approaching 3.2 Gbps per channel will be achieved.

  14. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  15. Characterization of high temperature-tolerant rhizobia isolated from Prosopis juliflora grown in alkaline soil.

    Science.gov (United States)

    Kulkarni, Suneeta; Nautiyal, Chandra Shekhar

    1999-10-01

    A method was developed for the fast screening and selection of high-temperature tolerant rhizobial strains from root nodules of Prosopis juliflora growing in alkaline soils. The high-temperature tolerant rhizobia were selected from 2,500 Rhizobium isolates with similar growth patterns on yeast mannitol agar plates after 72 h incubation at 30 and 45 degrees C, followed by a second screening at 47.5 degrees C. Seventeen high-temperature tolerant rhizobial strains having distinguishable protein band patterns were finally selected for further screening by subjecting them to temperature stress up to 60 degrees C in yeast mannitol broth for 6 h. The high-temperature tolerant strains were NBRI12, NBRI329, NBRI330, NBRI332, and NBRI133. Using this procedure, a large number of rhizobia from root nodules of P. juliflora were screened for high-temperature tolerance. The assimilation of several carbon sources, tolerance to high pH and salt stress, and ability to nodulate P. juliflora growing in a glasshouse and nursery of the strains were studied. All five isolates had higher plant dry weight in the range of 29.9 to 88.6% in comparison with uninoculated nursery-grown plants. It was demonstrated that it is possible to screen in nature for superior rhizobia exemplified by the isolation of temperature-tolerant strains, which established effective symbiosis with nursery-grown P. juliflora. These findings indicate a correlation between strain performance under in vitro stress in pure culture and strain behavior under symbiotic conditions. Pure culture evaluation may be a useful tool in search for Rhizobium strains better suited for soil environments where high temperature, pH, and salt stress constitutes a limitation for symbiotic biological nitrogen fixation.

  16. Novel AroA from Pseudomonas putida Confers Tobacco Plant with High Tolerance to Glyphosate

    Science.gov (United States)

    Yan, Hai-Qin; Chang, Su-Hua; Tian, Zhe-Xian; Zhang, Le; Sun, Yi-Cheng; Li, Yan; Wang, Jing; Wang, Yi-Ping

    2011-01-01

    Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, also designated as AroA), a key enzyme in the aromatic amino acid biosynthesis pathway in microorganisms and plants. Previously, we reported that a novel AroA (PpAroA1) from Pseudomonas putida had high tolerance to glyphosate, with little homology to class I or class II glyphosate-tolerant AroA. In this study, the coding sequence of PpAroA1 was optimized for tobacco. For maturation of the enzyme in chloroplast, a chloroplast transit peptide coding sequence was fused in frame with the optimized aroA gene (PparoA1optimized) at the 5′ end. The PparoA1optimized gene was introduced into the tobacco (Nicotiana tabacum L. cv. W38) genome via Agrobacterium-mediated transformation. The transformed explants were first screened in shoot induction medium containing kanamycin. Then glyphosate tolerance was assayed in putative transgenic plants and its T1 progeny. Our results show that the PpAroA1 from Pseudomonas putida can efficiently confer tobacco plants with high glyphosate tolerance. Transgenic tobacco overexpressing the PparoA1optimized gene exhibit high tolerance to glyphosate, which suggest that the novel PpAroA1 is a new and good candidate applied in transgenic crops with glyphosate tolerance in future. PMID:21611121

  17. Arbuscular Mycorrhizal Fungal Communities in the Roots of Maize Lines Contrasting for Al Tolerance Grown in Limed and Non-Limed Brazilian Oxisoil.

    Science.gov (United States)

    Gomes, Eliane A; Oliveira, Christiane A; Lana, Ubiraci G P; Noda, Roberto W; Marriel, Ivanildo E; de Souza, Francisco A

    2015-07-01

    Aluminum (Al) toxicity is one of the greatest limitations to agriculture in acid soils, particularly in tropical regions. Arbuscular mycorrhizal fungi (AMF) can supply plants with nutrients and give protection against Al toxicity. The aim of this work was to evaluate the effects of soil liming (i.e., reducing Al saturation) on the AMF community composition and structure in the roots of maize lines contrasting for Al tolerance. To this end, we constructed four 18S rDNA cloning libraries from L3 (Al tolerant) and L22 (Al sensitive) maize lines grown in limed and non-limed soils. A total of 790 clones were sequenced, 69% belonging to the Glomeromycota phylum. The remaining sequences were from Ascomycota, which were more prominent in the limed soil, mainly in the L3 line. The most abundant AM fungal clones were related to the family Glomeraceae represented by the genera uncultured Glomus followed by Rhizophagus and Funneliformis. However, the most abundant operational taxonomic units with 27% of the Glomeromycota clones was affiliated to genus Racocetra. This genus was present in all the four libraries, but it was predominant in the non-limed soils, suggesting that Racocetra is tolerant to Al toxicity. Similarly, Acaulospora and Rhizophagus were also present mostly in both lines in non-limed soils. The community richness of AMF in the non-limed soils was higher than the limed soil for both lines. The results suggest that the soil Al saturation was the parameter that mostly influences the AMF species composition in the soils in this study.

  18. Gate length scaling effect on high-electron mobility transistors devices using AlGaN/GaN and AlInN/AlN/GaN heterostructures.

    Science.gov (United States)

    Liao, S Y; Lu, C C; Chang, T; Huang, C F; Cheng, C H; Chang, L B

    2014-08-01

    Compared to AlGaN/GaN HEMT with 0.15 μm T-gate length, the AlInN/AlN/GaN one exhibits much higher current density and transconductance of 1558 mA/mm at Vd = 2 V and 330 mS/mm, respectively. The high extrinsic ft and fmax of 82 GHz and 70 GHz are extracted from AlInN/AlN/GaN HEMT. Besides, we find that the transconductance roll-off is significant in AlGaN/GaN, but largely improved in AlInN/AlN/GaN HEMT, suggesting that the high carrier density and lattice-matched epitaxial heterostructure is important to reach both large RF output power and high operation frequency, especially for an aggressively gate length scaling.

  19. High ethanol tolerance of the thermophilic anaerobic ethanol producer Thermoanaerobacter BG1L1

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Mikkelsen, Marie Just; Ahring, Birgitte Kiær

    2007-01-01

    The low ethanol tolerance of thermophilic anaerobic bacteria, generally less than 2% (v/v) ethanol, is one of the main limiting factors for their potential use for second generation fuel ethanol production. In this work, the tolerance of thermophilic anaerobic bacterium Thermoanaerobacter BG 1L1...... to exogenously added ethanol was studied in a continuous immobilized reactor system at a growth temperature of 70 degrees C. Ethanol tolerance was evaluated based on inhibition of fermentative performance e.g.. inhibition of substrate conversion. At the highest ethanol concentration tested (8.3% v/v), the strain...... was able to convert 42% of the xylose initially present, indicating that this ethanol concentration is not the upper limit tolerated by the strain. Long-term strain adaptation to high ethanol concentrations (6 - 8.3%) resulted in an improvement of xylose conversion by 25% at an ethanol concentration of 5...

  20. Enrichment and isolation of Flavobacterium strains with tolerance to high concentrations of cesium ion.

    Science.gov (United States)

    Kato, Souichiro; Goya, Eri; Tanaka, Michiko; Kitagawa, Wataru; Kikuchi, Yoshitomo; Asano, Kozo; Kamagata, Yoichi

    2016-02-17

    Interest in the interaction of microorganisms with cesium ions (Cs(+)) has arisen, especially in terms of their potent ability for radiocesium bioaccumulation and their important roles in biogeochemical cycling. Although high concentrations of Cs(+) display toxic effects on microorganisms, there have been only limited reports for Cs(+)-tolerant microorganisms. Here we report enrichment and isolation of Cs(+)-tolerant microorganisms from soil microbiota. Microbial community analysis revealed that bacteria within the phylum Bacteroidetes, especially Flavobacterium spp., dominated in enrichment cultures in the medium supplemented with 50 or 200 mM Cs(+), while Gammaproteobacteria was dominant in the control enrichment cultures (in the presence of 50 and 200 mM K(+) instead of Cs(+)). The dominant Flavobacterium sp. was successfully isolated from the enrichment culture and was closely related to Flavobacterium chungbukense with 99.5% identity. Growth experiments clearly demonstrated that the isolate has significantly higher tolerance to Cs(+) compared to its close relatives, suggesting the Cs(+)-tolerance is a specific trait of this strain, but not a universal trait in the genus Flavobacterium. Measurement of intracellular K(+) and Cs(+) concentrations of the Cs(+)-tolerant isolate and its close relatives suggested that the ability to maintain low intracellular Cs(+) concentration confers the tolerance against high concentrations of external Cs(+).

  1. High-capacity hydrogen storage in Al-adsorbed graphene

    Science.gov (United States)

    Ao, Z. M.; Peeters, F. M.

    2010-05-01

    A high-capacity hydrogen storage medium—Al-adsorbed graphene—is proposed based on density-functional theory calculations. We find that a graphene layer with Al adsorbed on both sides can store hydrogen up to 13.79wt% with average adsorption energy -0.193eV/H2 . Its hydrogen storage capacity is in excess of 6wt% , surpassing U. S. Department of Energy (DOE’s) target. Based on the binding-energy criterion and molecular-dynamics calculations, we find that hydrogen storage can be recycled at near ambient conditions. This high-capacity hydrogen storage is due to the adsorbed Al atoms that act as bridges to link the electron clouds of the H2 molecules and the graphene layer. As a consequence, a two-layer arrangement of H2 molecules is formed on each side of the Al-adsorbed graphene layer. The H2 concentration in the hydrogen storage medium can be measured by the change in the conductivity of the graphene layer.

  2. High-CO2 tolerance in microalgae: possible mechanisms and implications for biotechnology and bioremediation.

    Science.gov (United States)

    Solovchenko, Alexei; Khozin-Goldberg, Inna

    2013-11-01

    Recent developments in the field of microalgal biotechnology, including CO2 biomitigation and the discovery of new species of microalgae that are tolerant to extremely high CO2 levels (40-100 vol%), have renewed interest in the physiological effects and mechanisms of high-CO2 tolerance in photoautotrophs. Photosynthetic apparatus state transitions that increase ATP generation, upregulation of H(+)-ATPases pumping protons out of the cell, rapid shutdown of CO2-concentrating mechanisms, and adjustment of membranes' fatty acid composition are currently believed to be the key mechanisms governing cellular pH homeostasis and hence microalgae's tolerance to high CO2 levels, which is especially characteristic of extremophile and symbiotic species. The mechanisms governing acclimation to high CO2 comprise the subject of this review and are discussed in view of the use of CO2 enrichment to increase the productivity of microalgal cultures, as well as the practice of carbon capture from flue gases.

  3. Growth of AlGaN Epitaxial Film with High Al Content by Metalorganic Chemical Vapour Deposition

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-Lan; ZHAO De-Gang; YANG Hui; LIANG Jun-Wu

    2007-01-01

    A high-Al-content AlCaN epilayer is grown on a low-temperature-deposited AlN buffer on (0001) sapphire bylow pressure metalorganic chemical vapour deposition. The dependence of surface roughness, tilted mosaicity,and twisted mosaicity on the conditions of the AlCaN epilayer deposition is evaluated. An AlCaN epilayer withfavourable surface morphology and crystal quality is deposited on a 20nm low-temperature-deposited AlN buffer at a low Ⅴ/Ⅲ flow ratio of 783 and at a low reactor pressure of 100 Torr, and the adduct reaction between trimethylaluminium and NH3 is considered.

  4. Co-expression of G2-EPSPS and glyphosate acetyltransferase GAT genes conferring high tolerance to glyphosate in soybean

    OpenAIRE

    Bingfu eGuo; Yong eGuo; Huilong eHong; Longguo eJin; Lijuan eZhang; Ru-Zhen eChang; Wei eLu; Min eLin; Li-Juan eQiu

    2015-01-01

    Glyphosate is a widely used non-selective herbicide with broad spectrum of weed control around the world. At present, most of the commercial glyphosate tolerant soybeans utilize glyphosate tolerant gene CP4-EPSPS or glyphosate acetyltransferase gene GAT separately. In this study, both glyphosate tolerant gene G2-EPSPS and glyphosate degraded gene GAT were co-transferred into soybean and transgenic plants showed high tolerance to glyphosate. Molecular analysis including PCR, Sothern blot, qRT-...

  5. Liquid high-level waste storage - can we tolerate it?

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, P. [Terramares Group (United Kingdom)

    1996-12-31

    High-level radioactive waste from reprocessing is stored at British Nuclear Fuel`s Sellafield site in High Active Storage Tanks (HAST`s), which require constant cooling and ventilation. The author argues that, containing as they do, about 100 times the caesium 137 released during the Chernobyl accident, these containment tanks represent an unacceptably high risk of a major release of caesium 137, a volatile gamma-emitter with a half-life of about 30 years. It is readily transferred into food chains and difficult to remove from soils, tarmac and concrete. Still worse, it is argued, are the tens of thousands of cancers and other biological radiation effects likely to occur as a result of such a release. He argues for the vitrification of all such highly active liquid wastes, which would slow further reprocessing down to accommodate the current backlog. (UK).

  6. MgAl2O4–-Al2O3 solid solution interaction: mathematical framework and phase separation of -Al2O3 at high temperature

    Indian Academy of Sciences (India)

    Soumen Pal; A K Bandyopadhyay; S Mukherjee; B N Samaddar; P G Pal

    2011-07-01

    Although existence of MgAl2O4–-Al2O3 solid solution has been reported in the past, the detailed interactions have not been explored completely. For the first time, we report here a mathematical framework for the detailed solid solution interactions of -Al2O3 in MgAl2O4 (spinel). To investigate the solid solubility of -Al2O3 in MgAl2O4, Mg–Al spinel (MgO–Al2O3; = 1, 1.5, 3, 4.5 and an arbitrary high value 30) precursors have been heat treated at 1000°C. Presence of only non-stoichiometric MgAl2O4 phase up to = 4.5 at 1000°C indicates that alumina (as -Al2O3) present beyond stoichiometry gets completely accommodated in MgAl2O4 in the form of solid solution. → alumina phase transformation and its subsequent separation from MgAl2O4 has been observed in the Mg–Al spinel powders ( > 1) when the 1000°C heat treated materials are calcined at 1200°C. In the mathematical framework, unit cell of MgAl2O4 (Mg8Al16O32) has been considered for the solid solution interactions (substitution of Mg2+ ions by Al3+ ions) with -Al2O3. It is suggested that combination of unit cells of MgAl2O4 takes part in the interactions when > 5 (MgO–Al2O3).

  7. Energy dissipation of highly charged ions on Al oxide films.

    Science.gov (United States)

    Lake, R E; Pomeroy, J M; Sosolik, C E

    2010-03-03

    Slow highly charged ions (HCIs) carry a large amount of potential energy that can be dissipated within femtoseconds upon interaction with a surface. HCI-insulator collisions result in high sputter yields and surface nanofeature creation due to strong coupling between the solid's electronic system and lattice. For HCIs interacting with Al oxide, combined experiments and theory indicate that defect mediated desorption can explain reasonably well preferential O atom removal and an observed threshold for sputtering due to potential energy. These studies have relied on measuring mass loss on the target substrate or probing craters left after desorption. Our approach is to extract highly charged ions onto the Al oxide barriers of metal-insulator-metal tunnel junctions and measure the increased conductance in a finished device after the irradiated interface is buried under the top metal layer. Such transport measurements constrain dynamic surface processes and provide large sets of statistics concerning the way individual HCI projectiles dissipate their potential energy. Results for Xe(q +) for q = 32, 40, 44 extracted onto Al oxide films are discussed in terms of postirradiation electrical device characteristics. Future work will elucidate the relationship between potential energy dissipation and tunneling phenomena through HCI modified oxides.

  8. Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress tolerant crops

    Directory of Open Access Journals (Sweden)

    Craita eBita

    2013-07-01

    Full Text Available Global warming is predicted to have a general negative effect on plant growth due to the negative effect of high temperatures on plant development. The increasing threat of climatological extremes, including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review we assess the impact of global climate change on the production of agricultural crop production. There is a differential effect of climate change both in terms of geographic location and the crops that have will be likely to show the most extreme reductions in yield as a result of warming in general and the expected fluctuations in temperature. High temperature stress has a wide range of effects on plants both in terms of physiology, biochemistry and gene regulation pathways. In this review we present the recent advances of research on all these level of investigation focusing on potential leads that may help to understand more fully the mechanisms that make plants tolerant or susceptible to heat stress. Finally we review possible mechanisms and methods which can lead to the generation of new varieties that will allow sustainable yield production in a world likely to be challenged both by increasing population, higher average temperatures and larger temperature fluctuations.

  9. Highly tensile-strained Ge/InAlAs nanocomposites

    Science.gov (United States)

    Jung, Daehwan; Faucher, Joseph; Mukherjee, Samik; Akey, Austin; Ironside, Daniel J.; Cabral, Matthew; Sang, Xiahan; Lebeau, James; Bank, Seth R.; Buonassisi, Tonio; Moutanabbir, Oussama; Lee, Minjoo Larry

    2017-01-01

    Self-assembled nanocomposites have been extensively investigated due to the novel properties that can emerge when multiple material phases are combined. Growth of epitaxial nanocomposites using lattice-mismatched constituents also enables strain-engineering, which can be used to further enhance material properties. Here, we report self-assembled growth of highly tensile-strained Ge/In0.52Al0.48As (InAlAs) nanocomposites by using spontaneous phase separation. Transmission electron microscopy shows a high density of single-crystalline germanium nanostructures coherently embedded in InAlAs without extended defects, and Raman spectroscopy reveals a 3.8% biaxial tensile strain in the germanium nanostructures. We also show that the strain in the germanium nanostructures can be tuned to 5.3% by altering the lattice constant of the matrix material, illustrating the versatility of epitaxial nanocomposites for strain engineering. Photoluminescence and electroluminescence results are then discussed to illustrate the potential for realizing devices based on this nanocomposite material. PMID:28128282

  10. HIGH PROTON CONDUCTIVITY OF MESOPOROUS Al2O3

    Science.gov (United States)

    Shen, Hangyan; Maekawa, Hideki; Fujimaki, Yutaka; Kawada, Koutaro; Yamamura, Tsutomu

    Mesoporous Al2O3 was synthesized by the sol-gel method and the pore size was controlled over the range of 3-15nm. Proton conductivity of these samples was examined, which was as high as 0.004 S·cm-1 at 25°C. A systematic dependence of conductivity upon pore size was observed, in which the conductivity increased with increasing the pore size. Meanwhile the conductivity increased with increasing the humidity. Two peaks were observed in 1H NMR spectra, assigned to a "mobile" and an "immobile" proton, respectively. It can be seen that the conductivity of mesoporous-Al2O3 increased with increasing the "mobile" proton concentration. From TG-DTA measurement, proton species were categorized into three groups. It is suggested the group II protons have close relation with the NMR observed "mobile" protons.

  11. [Study on ethanol tolerance of Saccharomyces cerevisiae X330 under very high gravity medium].

    Science.gov (United States)

    Xue, Ying-Min; Jiang, Ning

    2006-05-01

    The impacts of osmoprotectants and nutrient components on both ethanol tolerance of Saccharomyces cerevisiae X330 and its ethanol fermentability were investigated when high gravity synthetic medium were used. The results indicate that nutrient limitation plays important role in the ethanol tolerance of Saccharomyces cerevisiae. When the nutritional requirements of Saccharomyces cerevisiae are satisfied, its ethanol tolerance increases, especially at high sugar concentrations. The effect of the individual nutrient component in the PYN medium on ethanol tolerance is different, which is yeast extract > peptone > magnesium sulfate > vitamin C = potassium phosphate > calcium chloride = ammonium sulfate. Osmoprotectants ( such as glycine and proline ) are effective in improving the ethanol tolerance of Saccharomyces cerevisiae X330, and the optimum concentrations of 20 mmol/L glycine and 10 mmol/L proline were obtained experimentally while glycine exerted a stronger enhancing effect than proline. After 3 h of exposure to 18% (V/V) ethanol at 30 degrees C, 57.1% and 50.0% remained viable for the cells grown in glycine-added and proline-added medium respectively.

  12. AL AVOIDANCE AND AL TOLERANCE OF MUCUNA-PRURIENS VAR UTILIS - EFFECTS OF A HETEROGENEOUS ROOT ENVIRONMENT AND THE NITROGEN FORM IN THE ROOT ENVIRONMENT

    NARCIS (Netherlands)

    HAIRIAH, K; STULEN, [No Value; VANNOORDWIJK, M; KUIPER, PJC

    1994-01-01

    In Mucuna pruriens var. utilis, grown with nitrate-N in a hydroponic split-root system, an Al avoidance reaction of root growth was observed, which was ascribed to local P stress in the Al containing compartment. The Al avoidance reaction was similar to the avoidance of Mucuna roots of acid subsoil

  13. AL AVOIDANCE AND AL TOLERANCE OF MUCUNA-PRURIENS VAR UTILIS - EFFECTS OF A HETEROGENEOUS ROOT ENVIRONMENT AND THE NITROGEN FORM IN THE ROOT ENVIRONMENT

    NARCIS (Netherlands)

    HAIRIAH, K; STULEN, [No Value; VANNOORDWIJK, M; KUIPER, PJC

    1994-01-01

    In Mucuna pruriens var. utilis, grown with nitrate-N in a hydroponic split-root system, an Al avoidance reaction of root growth was observed, which was ascribed to local P stress in the Al containing compartment. The Al avoidance reaction was similar to the avoidance of Mucuna roots of acid subsoil

  14. High tolerance to high-light conditions for the protected species Ariocarpus kotschoubeyanus (Cactaceae)

    Science.gov (United States)

    Arroyo-Pérez, Erika; González-Salvatierra, Claudia; Matías-Palafox, María L.; Jiménez-Sierra, Cecilia

    2017-01-01

    Abstract We determined the seasonal ecophysiological performance under perennial plants and under high solar radiation for adult individuals from the ‘living rock’ cactus Ariocarpus kotschoubeyanus, which occurs equally under nurse plants and in open spaces. We evaluated the effective quantum yield of photosystem II (ΦPSII) and the dissipation of thermal energy [non-photochemical quenching (NPQ)] thorough the year. The maximum apparent electron transport rate (ETRmax) and the saturating photosynthetically active photon flux density for PSII (PFDsat) were also determined from rapid light curves. We found that although the ΦPSII was higher in shaded sites under potential nurse plants than in exposed sites, all values were close to the optimal value of 0.83. The high ΦPSII found for A. kotschoubeyanus plants suggests that they use a great proportion of the absorbed light for photosynthesis, under nurse plants as well as in open spaces. We also found higher NPQ values in exposed sites than in shaded ones but only in Autumn, thus reducing the risk of photoinhibition. In addition, the PFDsat was higher in exposed sites than in shaded ones in Spring, Summer and Autumn, but in Winter there were no differences between treatments. We also found high saturating light levels for ETR (PFDsat higher than 1378 μmol m−2 s−1) in all seasons but in winter for shaded and non-shaded plants. Our findings indicate that A. kotschoubeyanus plants use a great proportion of the light that they absorb for photosynthesis. This high tolerance to high-light conditions could explain why A. kotschoubeyanus do not show preferences for protected sites under nurse plants. PMID:28729902

  15. Tolerance for High Flavanol Cocoa Powder in Semisweet Chocolate

    Science.gov (United States)

    Harwood, Meriel L.; Ziegler, Gregory R.; Hayes, John E.

    2013-01-01

    Endogenous polyphenolic compounds in cacao impart both bitter and astringent characteristics to chocolate confections. While an increase in these compounds may be desirable from a health perspective, they are generally incongruent with consumer expectations. Traditionally, chocolate products undergo several processing steps (e.g., fermentation and roasting) that decrease polyphenol content, and thus bitterness. The objective of this study was to estimate group rejection thresholds for increased content of cocoa powder produced from under-fermented cocoa beans in a semisweet chocolate-type confection. The group rejection threshold was equivalent to 80.7% of the non-fat cocoa solids coming from the under-fermented cocoa powder. Contrary to expectations, there were no differences in rejection thresholds when participants were grouped based on their self-reported preference for milk or dark chocolate, indicating that these groups react similarly to an increase in high cocoa flavanol containing cocoa powder. PMID:23792967

  16. Tolerance for High Flavanol Cocoa Powder in Semisweet Chocolate

    Directory of Open Access Journals (Sweden)

    John E. Hayes

    2013-06-01

    Full Text Available Endogenous polyphenolic compounds in cacao impart both bitter and astringent characteristics to chocolate confections. While an increase in these compounds may be desirable from a health perspective, they are generally incongruent with consumer expectations. Traditionally, chocolate products undergo several processing steps (e.g., fermentation and roasting that decrease polyphenol content, and thus bitterness. The objective of this study was to estimate group rejection thresholds for increased content of cocoa powder produced from under-fermented cocoa beans in a semisweet chocolate-type confection. The group rejection threshold was equivalent to 80.7% of the non-fat cocoa solids coming from the under-fermented cocoa powder. Contrary to expectations, there were no differences in rejection thresholds when participants were grouped based on their self-reported preference for milk or dark chocolate, indicating that these groups react similarly to an increase in high cocoa flavanol containing cocoa powder.

  17. Tolerance for high flavanol cocoa powder in semisweet chocolate.

    Science.gov (United States)

    Harwood, Meriel L; Ziegler, Gregory R; Hayes, John E

    2013-06-21

    Endogenous polyphenolic compounds in cacao impart both bitter and astringent characteristics to chocolate confections. While an increase in these compounds may be desirable from a health perspective, they are generally incongruent with consumer expectations. Traditionally, chocolate products undergo several processing steps (e.g., fermentation and roasting) that decrease polyphenol content, and thus bitterness. The objective of this study was to estimate group rejection thresholds for increased content of cocoa powder produced from under-fermented cocoa beans in a semisweet chocolate-type confection. The group rejection threshold was equivalent to 80.7% of the non-fat cocoa solids coming from the under-fermented cocoa powder. Contrary to expectations, there were no differences in rejection thresholds when participants were grouped based on their self-reported preference for milk or dark chocolate, indicating that these groups react similarly to an increase in high cocoa flavanol containing cocoa powder.

  18. Ultrahigh gain AlGaN/GaN high energy radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Howgate, J.D.; Schoell, S.J.; Schaefer, S.; Stutzmann, M.; Sharp, I.D. [Walter Schottky Institut and Physik Department, Technische Universitaet Muenchen, Am Coulombwall 4, 85748 Garching (Germany); Hofstetter, M.; Schmid, M.; Thalhammer, S. [Helmholtz Zentrum Muenchen, Ingolstaedter Landstrasse 1, 85764 Neuherberg (Germany); Zizak, I. [Helmholtz Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin (Germany); Hable, V.; Greubel, C.; Dollinger, G. [Institut fuer Angewandte Physik und Messtechnik LRT2, Werner-Heisenberg-Weg 39, 85577 Neubiberg (Germany)

    2012-08-15

    Due to its remarkable tolerance to high energy ionizing radiation, GaN has recently attracted attention as a promising material for dosimetry applications. However, materials issues that lead to persistent photoconductivity, poor sensitivity, and requirements for large operational voltages have been hurdles to realization of the full potential of this material. Here we demonstrate that the introduction of a two-dimensional electron gas channel, through the addition of AlGaN/GaN heterointerfaces, can be used to create intrinsic amplification of the number of electrons that can be collected from single ionization events, yielding exceptionally large sensitivities in ultralow dose rate regimes. Furthermore, anomalous photo-responses, which severely limit response times of GaN-based devices, can be eliminated using these heterostructures. Measurements using focused monochromatic synchrotron radiation at 1-20 keV, as well as focused 20 MeV protons, reveal that these devices provide the capability for high sensitivity and resolution real time monitoring, which is competitive with and complementary to state-of-the-art detectors. Therefore, AlGaN/GaN heterostructure devices are extremely promising for future applications in fields ranging from high energy physics to medical imaging. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. High temperature electron transport properties of AlGaN/GaN heterostructures with different Al-contents

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Electron transport properties in AlGaN/GaN heterostructures with different Al-contents have been in-vestigated from room temperature up to 680 K. The temperature dependencies of electron mobility have been systematically measured for the samples. The electron mobility at 680 K were measured as 154 and 182 cm2/V.s for Al0.15Ga0.85N/GaN and Al0.40Ga0.60N/GaN heterostructures,respectively. It was found that the electron mobility of low Al-content Al0.15Ga0.85N/GaN heterostructure was less than that of high Al-content Al0.40Ga0.60N/GaN heterostructure at high temperature of 680 K,which is different from that at room temperature. Detailed analysis showed that electron occupations in the first subband were 75% and 82% at 700 K for Al0.15Ga0.85N/GaN and Al0.40Ga0.60N/GaN heterostructures,respectively,and the two dimensional gas (2DEG) ratios in the whole electron system were 30% and near 60%,respectively. That indicated the 2DEG was better confined in the well,and was still dominant in the whole electron system for higher Al-content AlGaN/GaN heterostructure at 700 K,while lower one was not. Thus it had a higher electron mobility. So a higher Al-content AlGaN/GaN heterostructure is more suitable for high-temperature applications.

  20. Tolerance of Frogs among High School Students: Influences of Disgust and Culture

    Science.gov (United States)

    Prokop, Pavol; Medina-Jerez, William; Coleman, Joy; Fancovicová, Jana; Özel, Murat; Fedor, Peter

    2016-01-01

    Amphibians play an important role in the functioning of ecosystems and some of them inhabit human gardens where they can successfully reproduce. The decline of amphibian diversity worldwide suggests that people may play a crucial role in their survival. We conducted a cross-cultural study on high school students' tolerance of frogs in Chile,…

  1. Differences in FL Reading Comprehension among High-, Middle-, and Low-Ambiguity Tolerance Students.

    Science.gov (United States)

    El-Koumy, Abdel Salam A.

    The purpose of this study was to examine the differences in foreign language reading comprehension among high-, middle-, and low-ambiguity tolerance students. The subjects for the study were 150 English-as-a-Foreign-Language (EFL) university students randomly drawn from all freshmen enrolled in the English section at four schools of education in…

  2. Tolerance of Frogs among High School Students: Influences of Disgust and Culture

    Science.gov (United States)

    Prokop, Pavol; Medina-Jerez, William; Coleman, Joy; Fancovicová, Jana; Özel, Murat; Fedor, Peter

    2016-01-01

    Amphibians play an important role in the functioning of ecosystems and some of them inhabit human gardens where they can successfully reproduce. The decline of amphibian diversity worldwide suggests that people may play a crucial role in their survival. We conducted a cross-cultural study on high school students' tolerance of frogs in Chile,…

  3. Metal resistance or tolerance? Acidophiles confront high metal loads via both abiotic and biotic mechanisms

    Directory of Open Access Journals (Sweden)

    Mark eDopson

    2014-04-01

    Full Text Available All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Acidophilic microorganisms have an optimum growth pH < 3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account.

  4. High phase noise tolerant pilot-tone-aided DP-QPSK optical communication systems

    DEFF Research Database (Denmark)

    Zhang, Xu; Pang, Xiaodan; Deng, Lei

    2012-01-01

    In this paper we experimentally demonstrate a novel, high phase-noise tolerant, optical dual polarization (DP) quadrature phase-shift keying (QPSK) communication system based on pilot-tone-aided phase noise cancellation (PNC) algorithm. Vertical cavity surface emitting lasers (VCSELs...

  5. Liver Transplant Tolerance and Its Application to the Clinic: Can We Exploit the High Dose Effect?

    Directory of Open Access Journals (Sweden)

    Eithne C. Cunningham

    2013-01-01

    Full Text Available The tolerogenic properties of the liver have long been recognised, especially in regard to transplantation. Spontaneous acceptance of liver grafts occurs in a number of experimental models and also in a proportion of clinical transplant recipients. Liver graft acceptance results from donor antigen-specific tolerance, demonstrated by the extension of tolerance to other grafts of donor origin. A number of factors have been proposed to be involved in liver transplant tolerance induction, including the release of soluble major histocompatibility (MHC molecules from the liver, its complement of immunosuppressive donor leucocytes, and the ability of hepatocytes to directly interact with and destroy antigen-specific T cells. The large tissue mass of the liver has also been suggested to act as a cytokine sink, with the potential to exhaust the immune response. In this review, we outline the growing body of evidence, from experimental models and clinical transplantation, which supports a role for large tissue mass and high antigen dose in the induction of tolerance. We also discuss a novel gene therapy approach to exploit this dose effect and induce antigen-specific tolerance robust enough to overcome a primed T cell memory response.

  6. Screening of Purslane (Portulaca oleracea L. Accessions for High Salt Tolerance

    Directory of Open Access Journals (Sweden)

    Md. Amirul Alam

    2014-01-01

    Full Text Available Purslane (Portulaca oleracea L. is an herbaceous leafy vegetable crop, comparatively more salt-tolerant than any other vegetables with high antioxidants, minerals, and vitamins. Salt-tolerant crop variety development is of importance due to inadequate cultivable land and escalating salinity together with population pressure. In this view a total of 25 purslane accessions were initially selected from 45 collected purslane accessions based on better growth performance and subjected to 5 different salinity levels, that is, 0.0, 10.0, 20.0, 30.0, and 40.0 dS m−1 NaCl. Plant height, number of leaves, number of flowers, and dry matter contents in salt treated purslane accessions were significantly reduced (P≤0.05 and the enormity of reduction increased with increasing salinity stress. Based on dry matter yield reduction, among all 25 purslane accessions 2 accessions were graded as tolerant (Ac7 and Ac9, 6 accessions were moderately tolerant (Ac3, Ac5, Ac6, Ac10, Ac11, and Ac12, 5 accessions were moderately susceptible (Ac1, Ac2, Ac4, Ac8, and Ac13, and the remaining 12 accessions were susceptible to salinity stress and discarded from further study. The selected 13 purslane accessions could assist in the identification of superior genes for salt tolerance in purslane for improving its productivity and sustainable agricultural production.

  7. Highly methanol-tolerant platinum electrocatalyst derived from poly(vinylpoyrrolidone) coating

    Science.gov (United States)

    Yang, Zehui; Ling, Ying; Zhang, Yunfeng; Yang, Ming

    2017-02-01

    The design and fabrication of a methanol-tolerant electrocatalyst is still one of the most important issues in direct methanol fuel cells (DMFCs). Here, we focus on the design of a cathodic electrocatalyst in DMFCs and describe a new methanol-tolerant electrocatalyst fabricated from poly(vinylpyrrolidone) (PVP) coating on platinum nanoparticles assisted by hydrogen bonding between PVP and polybenzimidazole (PBI). The PVP layer has a negligible effect on the oxygen reduction reaction (ORR) activity, while the methanol oxidation reaction is retarded by the PVP layer. The PVP-coated electrocatalyst shows higher ORR activity under various methanol concentrations in the electrolyte, suggesting that the PVP-coated electrocatalyst has a higher methanol tolerance. Also, the PVP-coated electrocatalyst loses only 14% of the electrochemical surface area after 5000 potential cycles from 0.6-1.0 V versus the reversible hydrogen electrode, indicating better Pt stability than non-coated (27%) and commercial (38%) electrocatalysts due to the unique sandwich structure formed by the PVP and PBI. The power density of the PVP-coated electrocatalyst is four to five times higher compared to non-coated and commercial electrocatalysts with 12 M methanol feeding to the anode side, respectively. PVP coating is important for the enhancement of Pt stability and methanol tolerance. This study offers a new method for preparing a low-cost and high-methanol-tolerant Pt electrocatalyst, and useful information for real DMFC application to eliminate the methanol crossover problem in the cathode side.

  8. Auxotrophic Mutations Reduce Tolerance of Saccharomyces cerevisiae to Very High Levels of Ethanol Stress.

    Science.gov (United States)

    Swinnen, Steve; Goovaerts, Annelies; Schaerlaekens, Kristien; Dumortier, Françoise; Verdyck, Pieter; Souvereyns, Kris; Van Zeebroeck, Griet; Foulquié-Moreno, María R; Thevelein, Johan M

    2015-09-01

    Very high ethanol tolerance is a distinctive trait of the yeast Saccharomyces cerevisiae with notable ecological and industrial importance. Although many genes have been shown to be required for moderate ethanol tolerance (i.e., 6 to 12%) in laboratory strains, little is known of the much higher ethanol tolerance (i.e., 16 to 20%) in natural and industrial strains. We have analyzed the genetic basis of very high ethanol tolerance in a Brazilian bioethanol production strain by genetic mapping with laboratory strains containing artificially inserted oligonucleotide markers. The first locus contained the ura3Δ0 mutation of the laboratory strain as the causative mutation. Analysis of other auxotrophies also revealed significant linkage for LYS2, LEU2, HIS3, and MET15. Tolerance to only very high ethanol concentrations was reduced by auxotrophies, while the effect was reversed at lower concentrations. Evaluation of other stress conditions showed that the link with auxotrophy is dependent on the type of stress and the type of auxotrophy. When the concentration of the auxotrophic nutrient is close to that limiting growth, more stress factors can inhibit growth of an auxotrophic strain. We show that very high ethanol concentrations inhibit the uptake of leucine more than that of uracil, but the 500-fold-lower uracil uptake activity may explain the strong linkage between uracil auxotrophy and ethanol sensitivity compared to leucine auxotrophy. Since very high concentrations of ethanol inhibit the uptake of auxotrophic nutrients, the active uptake of scarce nutrients may be a major limiting factor for growth under conditions of ethanol stress. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  9. Alignment of primary Al3Ni phases in hypereutectic Al-Ni alloys with various compositions under high magnetic fields

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Al-Ni hypereutectic alloys with various compositions were solidified under various magnetic field con- ditions to investigate the alignment of primary Al3Ni phases. The results showed that the application of high magnetic fields could improve the homogeneity of the primary Al3Ni phase distribution and induce the alignment of primary Al3Ni phases in the direction perpendicular to the magnetic field direction to form chain-like structures. However, the alignment was different from the orientation of the Al3Ni phases. Furthermore, the degree of the alignment decreased with the increasing concentration of Ni element. This can be attributed to the combination effects of high magnetic field and alloy composition on the concentration field around the crystallized primary Al3Ni crystals.

  10. Identification of sugar-tolerant yeasts isolated from high-sugar fermented vegetable extracts.

    Science.gov (United States)

    Ok, Taing; Hashinaga, Fumio

    1997-02-01

    In Japan, high-sugar fermented vegetable extracts are novel functional food products for which sugar-tolerant yeasts are employed during processing. In order to understand the yeast distribution in these foods and their role in the functionality of such foods, we isolated sugar-tolerant yeasts from nine sample products, together with one sample each of fermented extract of ume (Japanese apricot) and honey. Twenty-three strains were identified as Zygosaccharomyces rouxii; one strain as Z. bailii; one strain as Torulaspora delbrueckii; and one strain as Candida bombicola. Nearly 90% of the identified strains belonged to Z. rouxii with variations in fermentation and assimilation properties. All strains grew well on 50% w/w glucose medium, and all but two strains grew on 60% w/w glucose medium. Sixteen strains belonged to the strong sugar tolerance type (poor or no growth at 1% and maximum growth at 30 or 40% w/w glucose); four strains to the moderate type (grew well at 1% and maximum growth at 10 or 20% w/w glucose); and seven strains to the weak type (maximum growth only at 1% w/w glucose). One strain of Z. rouxii, V19, grew up to 80% (w/w) glucose in liquid medium. In view of salt tolerance, only two strains belonged to the moderate type (maximum growth at 0.5 or 1 m NaCl); the remaining strains all belonged to the weak type (maximum growth only at 0 m NaCl). This suggests that sugar tolerance and salt tolerance of yeasts have different aspects.

  11. Fabrication of high thermal conductive Al-cBN ceramic sinters by high temperature high pressure method

    Science.gov (United States)

    Wang, P. F.; Li, Zh. H.; Zhu, Y. M.

    2011-05-01

    Al-cBN ceramic sinters were fabricated by sintering micro-powder mixture of Al and cBN under high temperature and high pressure condition. Differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electronic microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) elemental mapping analyses and laser flashing thermal conductivity measurements were performed to investigate the sintering properties and thermal conductivity of the Al-cBN ceramic sinters. XRD analysis revealed these Al-cBN ceramic sinters were composed of a large portion of cBN and of a small portion of AlN, and very little amount of AlB 12 and hBN. Formation of boundary phase resulted in the rapid densification of the sinters, as well as the increase of their relative density with increasing Al additions. The Al-cBN ceramic sinters have a maximum thermal conductivity of about 1.94 W/cm K at room temperature and a much higher value of about 2.04 W/cm K at 200 °C. Their high thermal conductivity over that of AlN-hBN composites promise Al-cBN ceramic sinters favorite candidates as high efficiency heat sink materials for wide band gap semiconductors.

  12. Personalized Metabolomics for Predicting Glucose Tolerance Changes in Sedentary Women After High-Intensity Interval Training

    OpenAIRE

    Kuehnbaum, Naomi L.; Gillen, Jenna B.; Gibala, Martin J.; Britz-McKibbin, Philip

    2014-01-01

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear. Herein, multi-segment injection capillary electrophoresis-mass spectrometry is used as a high-throughput platform in metabolomics to assess dynamic responses of overweight/obese women (BMI > 25, n = 11) to standardized oral glucose tolerance tests (OGTTs) performed before and after...

  13. Ky-2, a Histone Deacetylase Inhibitor, Enhances High-Salinity Stress Tolerance in Arabidopsis thaliana.

    Science.gov (United States)

    Sako, Kaori; Kim, Jong-Myong; Matsui, Akihiro; Nakamura, Kotaro; Tanaka, Maho; Kobayashi, Makoto; Saito, Kazuki; Nishino, Norikazu; Kusano, Miyako; Taji, Teruaki; Yoshida, Minoru; Seki, Motoaki

    2016-04-01

    Adaptation to environmental stress requires genome-wide changes in gene expression. Histone modifications are involved in gene regulation, but the role of histone modifications under environmental stress is not well understood. To reveal the relationship between histone modification and environmental stress, we assessed the effects of inhibitors of histone modification enzymes during salinity stress. Treatment with Ky-2, a histone deacetylase inhibitor, enhanced high-salinity stress tolerance in Arabidopsis. We confirmed that Ky-2 possessed inhibition activity towards histone deacetylases by immunoblot analysis. To investigate how Ky-2 improved salt stress tolerance, we performed transcriptome and metabolome analysis. These data showed that the expression of salt-responsive genes and salt stress-related metabolites were increased by Ky-2 treatment under salinity stress. A mutant deficient in AtSOS1(Arabidopis thaliana SALT OVERLY SENSITIVE 1), which encodes an Na(+)/H(+)antiporter and was among the up-regulated genes, lost the salinity stress tolerance conferred by Ky-2. We confirmed that acetylation of histone H4 at AtSOS1 was increased by Ky-2 treatment. Moreover, Ky-2 treatment decreased the intracellular Na(+)accumulation under salinity stress, suggesting that enhancement of SOS1-dependent Na(+)efflux contributes to increased high-salinity stress tolerance caused by Ky-2 treatment.

  14. Physiological basis for high CO2 tolerance in marine ectothermic animals: pre-adaptation through lifestyle and ontogeny?

    Directory of Open Access Journals (Sweden)

    M. Bleich

    2009-10-01

    efficient compensation of pH disturbances during exposure to elevated environmental pCO2. Compensation of extracellular acid-base status in turn may be important in avoiding metabolic depression. So far, maintained "performance" at higher seawater pCO2 (>0.3 to 0.6 kPa has only been observed in adults/juveniles of active, high metabolic species with a powerful ion regulatory apparatus. However, while some of these taxa are adapted to cope with elevated pCO2 during their regular embryonic development, gametes, zygotes and early embryonic stages, which lack specialized ion-regulatory epithelia, may be the true bottleneck for ecological success – even of the more tolerant taxa. Our current understanding of which marine animal taxa will be affected adversely in their physiological and ecological fitness by projected scenarios of anthropogenic ocean acidification is quite incomplete. While a growing amount of empirical evidence from CO2 perturbation experiments suggests that several taxa might react quite sensitively to ocean acidification, others seem to be surprisingly tolerant. However, there is little mechanistic understanding on what physiological traits are responsible for the observed differential sensitivities (see reviews of Seibel and Walsh, 2003; Pörtner et al., 2004; Fabry et al., 2008; Pörtner, 2008. This leads us to the first very basic question of how to define general CO2 tolerance on the species level.

  15. Physiological basis for high CO2 tolerance in marine ectothermic animals: pre-adaptation through lifestyle and ontogeny?

    Science.gov (United States)

    Melzner, F.; Gutowska, M. A.; Langenbuch, M.; Dupont, S.; Lucassen, M.; Thorndyke, M. C.; Bleich, M.; Pörtner, H.-O.

    2009-10-01

    pH disturbances during exposure to elevated environmental pCO2. Compensation of extracellular acid-base status in turn may be important in avoiding metabolic depression. So far, maintained "performance" at higher seawater pCO2 (>0.3 to 0.6 kPa) has only been observed in adults/juveniles of active, high metabolic species with a powerful ion regulatory apparatus. However, while some of these taxa are adapted to cope with elevated pCO2 during their regular embryonic development, gametes, zygotes and early embryonic stages, which lack specialized ion-regulatory epithelia, may be the true bottleneck for ecological success - even of the more tolerant taxa. Our current understanding of which marine animal taxa will be affected adversely in their physiological and ecological fitness by projected scenarios of anthropogenic ocean acidification is quite incomplete. While a growing amount of empirical evidence from CO2 perturbation experiments suggests that several taxa might react quite sensitively to ocean acidification, others seem to be surprisingly tolerant. However, there is little mechanistic understanding on what physiological traits are responsible for the observed differential sensitivities (see reviews of Seibel and Walsh, 2003; Pörtner et al., 2004; Fabry et al., 2008; Pörtner, 2008). This leads us to the first very basic question of how to define general CO2 tolerance on the species level.

  16. Microstructural Changes of Al Hot-Dipped P91 Steel during High-Temperature Oxidation

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Abro

    2017-02-01

    Full Text Available The 9Cr-1Mo steel (ASTM P91 was hot-dip aluminized, and its microstructural changes during oxidation were studied. Before oxidation, the coating consisted of (Al-rich topcoat containing a small amount of Al5Fe2 and Al13Fe4/(Al13Fe4-rich, Al13Fe4-containing alloy layer/(Al5Fe2 alloy layer containing a small amount of Al9Cr4 precipitates, from the surface. During oxidation at 700–900 °C for 20–100 h, Al diffused inward and the substrate elements migrated outward to broaden and soften the coating, and also to transform (high Al-Fe intermetallics to (low Al-Fe intermetallics. The phases in the coating progressively transformed during oxidation as follows; (Al-rich topcoat/(Al5Fe2–rich, Al13Fe4-containing alloy layer/(Al5Fe2 alloy layer→(α-Al2O3 scale/(Al13Fe4–rich, Al5Fe2-containing layer/(Al5Fe2 layer/(AlFe interlayer→(α-Al2O3 scale/(AlFe–rich, Al5Fe2-containing layer/(AlFe layer/(AlFe3 layer→((α-Al2O3, Fe2O3-mixed scale/(AlFe3 layer/(Fe(Al layer from the surface. As the oxidation progressed, the scale changed from α-Al2O3 to the (α-Al2O3, Fe2O3-mixture, which provided the necessary oxidation resistance.

  17. Heat priming induces trans-generational tolerance to high temperature stress in wheat

    Directory of Open Access Journals (Sweden)

    Xiao eWang

    2016-04-01

    Full Text Available Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH, the progeny of heat-primed plants (PH possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were related to signal transduction, transcription, energy, defense, and protein destination and storage, respectively. The gene encoding the lysine-specific histone demethylase 1 (LSD1 which was involved in histone demethylation related to epigenetic modification was up-regulated in the PH compared with NH. The proteome analysis indicated that the proteins involved in photosynthesis, energy production and protein destination and storage were up-regulated in the PH compared with NH. In short, thermos-tolerance was induced through heritable epigenetic alternation and signaling transduction, both processes further triggered prompt modifications of defense related responses in anti-oxidation, transcription, energy production, and protein destination and storage in the progeny of the primed plants under high temperature stress. It was concluded that trans-generation thermo-tolerance was induced by heat priming in the first generation, and this might be an effective measure to cope with severe high-temperature stresses during key growth stages in wheat production.

  18. Heat Priming Induces Trans-generational Tolerance to High Temperature Stress in Wheat

    Science.gov (United States)

    Wang, Xiao; Xin, Caiyun; Cai, Jian; Zhou, Qin; Dai, Tingbo; Cao, Weixing; Jiang, Dong

    2016-01-01

    Wheat plants are very sensitive to high temperature stress during grain filling. Effects of heat priming applied to the first generation on tolerance of the successive generation to post-anthesis high temperature stress were investigated. Compared with the progeny of non-heat primed plants (NH), the progeny of heat-primed plants (PH) possessed higher grain yield, leaf photosynthesis and activities of antioxidant enzymes and lower cell membrane damage under high temperature stress. In the transcriptome profile, 1430 probes showed obvious difference in expression between PH and NH. These genes were related to signal transduction, transcription, energy, defense, and protein destination and storage, respectively. The gene encoding the lysine-specific histone demethylase 1 (LSD1) which was involved in histone demethylation related to epigenetic modification was up-regulated in the PH compared with NH. The proteome analysis indicated that the proteins involved in photosynthesis, energy production and protein destination and storage were up-regulated in the PH compared with NH. In short, thermos-tolerance was induced through heritable epigenetic alternation and signaling transduction, both processes further triggered prompt modifications of defense related responses in anti-oxidation, transcription, energy production, and protein destination and storage in the progeny of the primed plants under high temperature stress. It was concluded that trans-generation thermo-tolerance was induced by heat priming in the first generation, and this might be an effective measure to cope with severe high-temperature stresses during key growth stages in wheat production. PMID:27148324

  19. Polyamine Accumulation in Transgenic Tomato Enhances the Tolerance to High Temperature Stress

    Institute of Scientific and Technical Information of China (English)

    Lin Cheng; Yijing Zou; Shuli Ding; Jiajing Zhang; Xiaolin Yu; Jiashu Cao; Gang Lu

    2009-01-01

    Polyamines play an important role in plant response to abiotic stress. S-adenosyl-I-methionine decarboxylase (SAMDC) is one of the key regulatory enzymes in the biosynthesis of polyamines. In order to better understand the effect of regulation of polyamine biosynthesis on the tolerance of high-temperature stress in tomato, SAMDC Cdna isolated from Saccharomyces cerevisiae was introduced into tomato genome by means of Agrobacterium tumefaciens through leaf disc transformation. Transgene and expression was confirmed by Southern and Northern blot analyses, respectively. Transgenic plants expressing yeast SAMDC produced 1.7- to 2.4-fold higher levels of spermidine and spermine than wild-type plants under high temperature stress, and enhanced antioxidant enzyme activity and the protection of membrane lipid peroxidation was also observed. This subsequently improved the efficiency of CO2 assimilation and protected the plants from high temperature stress, which indicated that the transgenic tomato presented an enhanced tolerance to high temperature stress (38℃) compared with wild-type plants, Our results demonstrated clearly that increasing polyamine biosynthesis in plants may be a means of creating high temperature-tolerant germplasm.

  20. Transgenic peppers that are highly tolerant to a new CMV pathotype.

    Science.gov (United States)

    Lee, Yun Hee; Jung, Min; Shin, Sun Hee; Lee, Ji Hee; Choi, Soon Ho; Her, Nam Han; Lee, Jang Ha; Ryu, Ki Hyun; Paek, Kee Yoeup; Harn, Chee Hark

    2009-02-01

    The CMV (cucumber mosaic virus) is the most frequently occurring virus in chili pepper farms. A variety of peppers that are resistant to CMVP0 were developed in the middle of 1990s through a breeding program, and commercial cultivars have since been able to control the spread of CMVP0. However, a new pathotype (CMVP1) that breaks the resistance of CMVP0-resistant peppers has recently appeared and caused a heavy loss in productivity. Since no genetic source of this new pathotype was available, a traditional breeding method cannot be used to generate a CMVP1-resistant pepper variety. Therefore, we set up a transformation system of pepper using Agrobacterium that had been transfected with the coat protein gene, CMVP0-CP, with the aim of developing a new CMVP1-resistant pepper line. A large number of transgenic peppers (T(1), T(2) and T(3)) were screened for CMVP1 tolerance using CMVP1 inoculation. Transgenic peppers tolerant to CMVP1 were selected in a plastic house as well as in the field. Three independent T(3) pepper lines highly tolerant to the CMVP1 pathogen were found to also be tolerant to the CMVP0 pathogen. These selected T(3) pepper lines were phenotypically identical or close to the non-transformed lines. However, after CMVP1 infection, the height and fruit size of the non-transformed lines became shorter and smaller, respectively, while the T(3) pepper lines maintained a normal phenotype.

  1. Butter improves glucose tolerance compared with at highly polyunsaturated diet in the rat

    DEFF Research Database (Denmark)

    Hellgren, Lars

    -fat on glucose-tolerance in intervention studies. Methods: 16 rats were divided into two groups and fed a semisynthetic diet containing 31 E-% fat, either as butter or highly polyunsaturated grapeseed oil. After 12 weeks on the diets, glucose-tolerance was assayed with the oral-glucose tolerance test (OGTT......). Results and Discussion: The OGTT revealed that the rats on the butter-containing diet, had a substantially higher glucose tolerance than the rats, which were fed grapeseed oil (area under the curve =195  31 mM*min-2 vs. 310  13 mM*min-2, n= 8, p=0.004). There were no differences in serum triacylglycerol...... (TAG), serum free fatty acid and leptin between the groups. However, the butter-fed rats had a lower content of TAG in the white gastrocnemius muscle (7.7  1.5 vs. 23.1  6.2 mg/g tissue, p=0.01), and a much higher n-3 PUFA content (total n-3 PUFAs 1,43  0.06 vs 0.73  0.02g/mg tissue, p

  2. In-situ tube burst testing and high-temperature deformation behavior of candidate materials for accident tolerant fuel cladding

    Science.gov (United States)

    Gussev, M. N.; Byun, T. S.; Yamamoto, Y.; Maloy, S. A.; Terrani, K. A.

    2015-11-01

    One of the most essential properties of accident tolerant fuel (ATF) for maintaining structural integrity during a loss-of-coolant accident (LOCA) is high resistance of the cladding to plastic deformation and burst failure, since the deformation and burst behavior governs the cooling efficiency of flow channels and the process of fission product release. To simulate and evaluate the deformation and burst process of thin-walled cladding, an in-situ testing and evaluation method has been developed on the basis of visual imaging and image analysis techniques. The method uses a specialized optics system consisting of a high-resolution video camera, a light filtering unit, and monochromatic light sources. The in-situ testing is performed using a 50 mm long pressurized thin-walled tubular specimen set in a programmable furnace. As the first application, ten (10) candidate cladding materials for ATF, i.e., five FeCrAl alloys and five nanostructured steels, were tested using the newly developed method, and the time-dependent images were analyzed to produce detailed deformation and burst data such as true hoop stress, strain (creep) rate, and failure stress. Relatively soft FeCrAl alloys deformed and burst below 800 °C, while negligible strain rates were measured for higher strength alloys.

  3. Hydrogen peroxide-scavenging enzymes impart tolerance to high temperature induced oxidative stress in sugarcane.

    Science.gov (United States)

    Srivastava, Sangeeta; Pathak, Ashwini Dutt; Gupta, Prashant Shekhar; Shrivastava, Ashok Kumar; Srivastava, Arun Kumar

    2012-05-01

    Seventy-one genotypes of sugarcane from diverse agro-climatic zones of India viz. peninsular, northwest, north-central and eastern zones, were screened for their tolerance to high temperature stress based on the damage to leaf biomass i.e. necrosis of leaf-tips and margins, and rolling of leaves. Nine selected genotypes showing variable response to heat injury were tested for activity pattern of isoforms of two H2O2-scavenging enzymes; ascorbate peroxidase (APX) and catalase (CAT), under high temperature induced oxidative stress. Changes in the activity of APX and CAT isozymes in leaves corresponded to the level of tolerance of genotypes towards heat injury which was substantiated by the highly negative correlation coefficients of heat injury levels of leaves vs. integrated density of APX and CAT isozyme bands. This indicated that the criteria of higher expression of CATs' andAPXs', the two major reactive oxygen species scavenging proteins in leaves may be used to screen large seedling populations and germplasm for high temperature tolerance.

  4. Aspects of high-cycle fatigue performance in a Ti-6Al-4V alloy

    Energy Technology Data Exchange (ETDEWEB)

    Boyce, B.L.; Campbell, J.P.; Roder, O.; Thompson, A.W.; Ritchie, R.O.

    1999-07-01

    Determination of critical levels of microstructural damage that can lead to fatigue crack propagation under high-cycle fatigue loading conditions is a major concern for the aircraft industry regarding structural integrity of turbine engine components. The cyclic frequencies characteristic of service loading spectra are extremely high and appear to require a damage-tolerant design approach. One idea for such an approach is to attempt to define a practical, appropriate crack-propagation threshold, {Delta}K{sub TH}. The present study identifies a practical lower-bound large-crack threshold under high-cycle fatigue conditions in a Ti-6 Al-4V blade alloy (with {approximately}60% primary {alpha} in a matrix of lamellar {alpha}+{beta}). The authors suggest that lower-bound thresholds can be determined by modifying standard large-crack propagation tests to simulate small-crack behavior. Modification techniques include high load-ratio testing under both constant-R and constant-K{sub max} conditions, performed at cyclic loading frequencies up to 1 kHz and R ratios up to 0.95. The results of these tests are compared to the near-threshold behavior of naturally-initiated small cracks, and to the crack initiation and early growth behavior of small cracks emanating from sites of simulated foreign object damage.

  5. Statistics-based reconstruction method with high random-error tolerance for integral imaging.

    Science.gov (United States)

    Zhang, Juan; Zhou, Liqiu; Jiao, Xiaoxue; Zhang, Lei; Song, Lipei; Zhang, Bo; Zheng, Yi; Zhang, Zan; Zhao, Xing

    2015-10-01

    A three-dimensional (3D) digital reconstruction method for integral imaging with high random-error tolerance based on statistics is proposed. By statistically analyzing the points reconstructed by triangulation from all corresponding image points in an elemental images array, 3D reconstruction with high random-error tolerance could be realized. To simulate the impacts of random errors, random offsets with different error levels are added to a different number of elemental images in simulation and optical experiments. The results of simulation and optical experiments showed that the proposed statistic-based reconstruction method has relatively stable and better reconstruction accuracy than the conventional reconstruction method. It can be verified that the proposed method can effectively reduce the impacts of random errors on 3D reconstruction of integral imaging. This method is simple and very helpful to the development of integral imaging technology.

  6. Dried Colony in Cyanobacterium, Nostoc sp. HK-01 — Several high Space Environment Tolerances for ``Tanpopo'' Mission

    Science.gov (United States)

    Tomita-Yokotani, K.; Kimura, S.; Kimura, Y.; Igarashi, Y.; Ajioka, R.; Sato, S.; Katoh, H.; Baba, K.

    2013-11-01

    A cyanobacterium, Nostoc sp. HK-01, has high several space environmental tolerance. Nostoc sp HK-01 would have high contribution for the “Tanpopo” mission in Japan Experimental Module of the International Space Station.

  7. Co-expression of G2-EPSPS and glyphosate acetyltransferase GAT genes conferring high tolerance to glyphosate in soybean

    Directory of Open Access Journals (Sweden)

    Bingfu eGuo

    2015-10-01

    Full Text Available Glyphosate is a widely used non-selective herbicide with broad spectrum of weed control around the world. At present, most of the commercial glyphosate tolerant soybeans utilize glyphosate tolerant gene CP4-EPSPS or glyphosate acetyltransferase gene GAT separately. In this study, both glyphosate tolerant gene G2-EPSPS and glyphosate degraded gene GAT were co-transferred into soybean and transgenic plants showed high tolerance to glyphosate. Molecular analysis including PCR, Sothern blot, qRT-PCR and Western blot revealed that target genes have been integrated into genome and expressed effectively at both mRNA and protein levels. Furthermore, the glyphosate tolerance analysis showed that no typical symptom was observed when compared with a glyphosate tolerant line HJ06-698 derived from GR1 transgenic soybean even at four-fold labeled rate of Roundup. Chlorophyll and shikimic acid content analysis of transgenic plant also revealed that these two indexes were not significantly altered after glyphosate application. These results indicated that co-expression of G2-EPSPS and GAT conferred high tolerance to the herbicide glyphosate in soybean. Therefore, combination of tolerant and degraded genes provides a new strategy for developing glyphosate tolerant transgenic crops.

  8. Development of powder metallurgy 2XXX series Al alloys for high temperature aircraft structural applications

    Science.gov (United States)

    Chellman, D. J.

    1984-01-01

    The objective of the present investigation was to improve the strength and fracture toughness combination of P/M 2124 Al alloys in accordance with NASA program goals for damage tolerance and fatigue resistance. Two (2) P/M compositions based on Al-3.70 Cu-1.85 Mg-0.20 Mn with 0.12 and 0.60 wt. pct. Zr were selected for investigation. The rapid solidification rates produced by atomization were observed to prohibit the precipitation of coarse, primary Al3Zr in both alloys. A major portion of the Zr precipitated as finely distributed, coherent Al3Zr phases during vacuum preheating and solution heat treatment. The proper balance between Cu and Mg contents eliminated undissolved, soluble constituents such as Al2CuMg and Al2Cu during atomization. The resultant extruded microstructures produced a unique combination of strength and fracture toughness. An increase in the volume fraction of coherent Al3Zr, unlike incoherent Al20Cu2Mn3 dispersoids, strengthened the P/M Al base alloy either directly by dislocation-precipitate interactions, indirectly by a retardation of recrystallization, or a combination of both mechanisms. Furthermore, coherent Al3Zr does not appear to degrade toughness to the extent that incoherent Al20Cu2Mn3 does. Consequently, the addition of 0.60 wt. pct. Zr to the base alloy, incorporated with a 774K (935 F) solution heat treatment temperature, produces an alloy which exceeds all tensile property and fracture toughness goals for damage tolerant and fatigue resistant applications in the naturally aged condition.

  9. Synthesis and characterization of high volume fraction Al-Al{sub 2}O{sub 3} nanocomposite powders by high-energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, B. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Suryanarayana, C. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States)]. E-mail: csuryana@mail.ucf.edu; An, L. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816-2455 (United States); Vaidyanathan, R. [Department of Mechanical, Materials, and Aerospace Engineering, University of Central Florida, Orlando, FL 32816-2450 (United States); Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816-2455 (United States)

    2006-06-15

    Al-Al{sub 2}O{sub 3} metal matrix composite (MMC) powders with volume fractions of 20, 30, and 50% Al{sub 2}O{sub 3} were synthesized by high-energy milling of the blended component powders. The particle sizes of Al{sub 2}O{sub 3} studied were 50 nm, 150 nm, and 5 {mu}m. A uniform distribution of the Al{sub 2}O{sub 3} reinforcement in the Al matrix was successfully obtained after milling the powders for a period of 20 h at a ball-to-powder ratio of 10:1 in a SPEX mill. The uniform distribution of Al{sub 2}O{sub 3} in the Al matrix was confirmed by characterizing these nanocomposite powders by scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray mapping, and X-ray diffraction (XRD) techniques.

  10. Highly efficient bioethanol production by a Saccharomyces cerevisiae strain with multiple stress tolerance to high temperature, acid and ethanol.

    Science.gov (United States)

    Benjaphokee, Suthee; Hasegawa, Daisuke; Yokota, Daiki; Asvarak, Thipa; Auesukaree, Choowong; Sugiyama, Minetaka; Kaneko, Yoshinobu; Boonchird, Chuenchit; Harashima, Satoshi

    2012-02-15

    Use of super strains exhibiting tolerance to high temperature, acidity and ethanol is a promising way to make ethanol production economically feasible. We describe here the breeding and performance of such a multiple-tolerant strain of Saccharomyces cerevisiae generated by a spore-to-cell hybridization technique without recombinant DNA technology. A heterothallic strain showing a high-temperature (41°C) tolerant (Htg(+)) phenotype, a derivative from a strain isolated from nature, was crossed with a homothallic strain displaying high-ethanol productivity (Hep(+)), a stock culture at the Thailand Institute of Scientific and Technological Research. The resultant hybrid TJ14 displayed ability to rapidly utilize glucose, and produced ethanol (46.6g/l) from 10% glucose fermentation medium at high temperature (41°C). Not only ethanol productivity at 41°C but also acid tolerance (Acd(+)) was improved in TJ14 as compared with its parental strains, enabling TJ14 to grow in liquid medium even at pH 3. TJ14 maintained high ethanol productivity (46.0g/l) from 10% glucose when fermentation was done under multiple-stress conditions (41°C and pH 3.5). Furthermore, when TJ14 was subjected to a repeated-batch fermentation scheme, the growth and ethanol production of TJ14 were maintained at excellent levels over ten cycles of fermentation. Thus, the multiple-stress (Htg(+) Hep(+) Acd(+)) resistant strain TJ14 should be useful for cost-effective bioethanol production under high-temperature and acidic conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Culturable associated-bacteria of the sponge Theonella swinhoei show tolerance to high arsenic concentrations

    Directory of Open Access Journals (Sweden)

    Ray eKeren

    2015-02-01

    Full Text Available Sponges are potent filter feeders and as such are exposed to high fluxes of toxic trace elements, which can accumulate in their body over time. Such is the case of the Red Sea sponge Theonella swinhoei, which has been shown to accumulate up to 8500 mg/Kg of the highly toxic element arsenic. T. swinhoei is known to harbor a multitude of sponge-associated bacteria, so it is hypothesized that the associated-bacteria will be tolerant to high arsenic concentration. This study also investigates the fate of the arsenic accumulated in the sponge to test if the associated-bacteria have an important role in the arsenic accumulation process of their host, since bacteria are key players in the natural arsenic cycle. Separation of the sponge to sponge cells and bacteria enriched fractions showed that arsenic is accumulated by the bacteria. Sponge-associated, arsenic-tolerant bacteria were cultured in the presence of 5 mM of either arsenate or arsenite (equivalent to 6150 mg/Kg arsenic, dry weight. The 54 isolated bacteria were grouped to 15 OTUs and isolates belonging to 12 OTUs were assessed for tolerance to arsenate at increased concentrations up to 100 mM. Eight of the 12 OTUs tolerated an order of magnitude increase in the concentration of arsenate, and some exhibited external biomineralization of arsenic-magnesium salts. The biomineralization of this unique mineral was directly observed in bacteria for the first time. These results may provide an explanation for the ability of the sponge to accumulate considerable amounts of arsenic. Furthermore arsenic-mineralizing bacteria can potentially be used for the study of bioremediation, as arsenic toxicity affects millions of people worldwide.

  12. Impaired glucose tolerance in rats fed low-carbohydrate, high-fat diets.

    Science.gov (United States)

    Bielohuby, Maximilian; Sisley, Stephanie; Sandoval, Darleen; Herbach, Nadja; Zengin, Ayse; Fischereder, Michael; Menhofer, Dominik; Stoehr, Barbara J M; Stemmer, Kerstin; Wanke, Rüdiger; Tschöp, Matthias H; Seeley, Randy J; Bidlingmaier, Martin

    2013-11-01

    Moderate low-carbohydrate/high-fat (LC-HF) diets are widely used to induce weight loss in overweight subjects, whereas extreme ketogenic LC-HF diets are used to treat neurological disorders like pediatric epilepsy. Usage of LC-HF diets for improvement of glucose metabolism is highly controversial; some studies suggest that LC-HF diets ameliorate glucose tolerance, whereas other investigations could not identify positive effects of these diets or reported impaired insulin sensitivity. Here, we investigate the effects of LC-HF diets on glucose and insulin metabolism in a well-characterized animal model. Male rats were fed isoenergetic or hypocaloric amounts of standard control diet, a high-protein "Atkins-style" LC-HF diet, or a low-protein, ketogenic, LC-HF diet. Both LC-HF diets induced lower fasting glucose and insulin levels associated with lower pancreatic β-cell volumes. However, dynamic challenge tests (oral and intraperitoneal glucose tolerance tests, insulin-tolerance tests, and hyperinsulinemic euglycemic clamps) revealed that LC-HF pair-fed rats exhibited impaired glucose tolerance and impaired hepatic and peripheral tissue insulin sensitivity, the latter potentially being mediated by elevated intramyocellular lipids. Adjusting visceral fat mass in LC-HF groups to that of controls by reducing the intake of LC-HF diets to 80% of the pair-fed groups did not prevent glucose intolerance. Taken together, these data show that lack of dietary carbohydrates leads to glucose intolerance and insulin resistance in rats despite causing a reduction in fasting glucose and insulin concentrations. Our results argue against a beneficial effect of LC-HF diets on glucose and insulin metabolism, at least under physiological conditions. Therefore, use of LC-HF diets for weight loss or other therapeutic purposes should be balanced against potentially harmful metabolic side effects.

  13. High temperature properties of CrAlN, CrAlSiN and AlCrSiN coatings - Structure and oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Polcar, Tomas, E-mail: polcar@fel.cvut.cz [Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technicka 2, Prague 6 (Czech Republic); SEG-CEMUC - Department of Mechanical Engineering, University of Coimbra, Rua Luis Reis Santos, P-3030 788 Coimbra (Portugal); Cavaleiro, Albano [SEG-CEMUC - Department of Mechanical Engineering, University of Coimbra, Rua Luis Reis Santos, P-3030 788 Coimbra (Portugal)

    2011-09-15

    Highlights: {yields} Deposition and structural analysis of CrAln, CrAlSiN and AlCrSiN coatings. {yields} In-situ XRD analysis at high temperature. {yields} AlCrSiN coating showed the highest oxidation resistance and thermal stability. {yields} CrAlN outperformed CrAlSiN film both in oxidation resistance and thermal stability. - Abstract: CrAlN, CrAlSiN and AlCrSiN coatings were deposited by cathodic arc deposition technique from composite targets. Three targets were used: (i) Cr/Al ratio close to 1, (ii) Cr/Al ratio close to 1 with Si addition, and (iii) Cr/Al ratio close to 1/2 and Si addition. Nitrogen flow was kept constant during the depositions. The Cr/Al ratio of the films, measured by electron probe microanalysis (EPMA), was similar to that of the target and the silicon content was in the range 3-4 at.%. The coatings were deposited onto FeCrAl alloy and WC/Co mirror-polished substrates. To analyze the coating structure, X-ray photoelectron (XPS) and X-ray diffraction (XRD) analysis were used. The evolution of the coating structure up to 1000 deg. C was in situ measured in a XRD apparatus equipped with heating plate. The films oxidation behavior was characterized by thermogravimetric analysis (TGA) at two selected temperatures. The annealed coatings were analyzed by XRD and scanning electron microscopy with energy-dispersive X-ray spectroscopy (EDX). CrAlSiN showed low oxidation resistance being partially oxidized at 800 deg. C. Moreover, the film exhibited low thermal stability, since the cubic nitride phases transformed to hexagonal nitrides at relatively low temperatures. CrAlN oxidation behavior was more promising; nevertheless, AlCrSiN showed excellent thermal stability with cubic nitrides observed even after heating to 1300 deg. C. The oxidation of this film at 900 and 1000 deg. C was negligible.

  14. Impact of strain relaxation of AlGaN barrier layer on the performance of high Al-content AlGaN/GaN HEMT

    Institute of Scientific and Technical Information of China (English)

    YANG Yan; HAO Yue; ZHANG Jincheng; WANG Chong; FENG Qian

    2006-01-01

    The effects of strain relaxation of AlGaN barrier layer on the conduction band profile, electron concentration and two-dimensional gas (2DEG) sheet charge density in a high Al-content AlGaN/GaN high electron mobility transistor (HEMT) are calculated by self-consistently solving Poisson's and Schr(o)dinger's equations. The effect of strain relaxation on dc I-V characteristics of AlxGa1-xN/GaN HEMT is obtained by developing a nonlinear charge-control model that describes the accurate relation of 2DEG sheet charge density and gate voltage. The model predicts a highest 2DEG sheet charge density of 2.42×1013 cm-2 and maximum saturation current of 2482.8 mA/mm at a gate bias of 2 V for 0.7 μm Al0.50Ga0.50N/GaN HEMT with strain relaxation r =0 and 1.49×1013 cm-2 and 1149.7 mA/mm with strain relaxation r =1. The comparison between simulations and physical measurements shows a good agreement. Results show that the effect of strain relaxation must be considered when analyzing the characteristics of high Al-content AlGaN/GaN HEMT theoretically, and the performance of the devices is improved by decreasing the strain relaxation of AlGaN barrier layer.

  15. Effect of Mg{sup 2+} ions co-doping on timing performance and radiation tolerance of Cerium doped Gd{sub 3}Al{sub 2}Ga{sub 3}O{sub 12} crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lucchini, M.T., E-mail: Marco.Toliman.Lucchini@cern.ch [CERN, 1211 Geneva 23 (Switzerland); Babin, V.; Bohacek, P. [Institute of Physics AS CR, Prague (Czech Republic); Gundacker, S. [CERN, 1211 Geneva 23 (Switzerland); Kamada, K. [Tohoku University, New Industry Creation Hatchery Center, Sendai (Japan); C& A Corporation, T-Biz, Sendai (Japan); Nikl, M. [Institute of Physics AS CR, Prague (Czech Republic); Petrosyan, A. [Institute for Physical Research, Ashtarak (Armenia); Yoshikawa, A. [Tohoku University, New Industry Creation Hatchery Center, Sendai (Japan); Tohoku University, Institute for Material Research, Sendai (Japan); C& A Corporation, T-Biz, Sendai (Japan); Auffray, E. [CERN, 1211 Geneva 23 (Switzerland)

    2016-04-21

    Inorganic scintillators with high density and high light yield are of major interest for applications in medical imaging and high energy physics detectors. In this work, the optical and scintillation properties of Mg co-doped Ce:Gd{sub 3}Al{sub 2}Ga{sub 3}O{sub 12} crystals, grown using Czochralski technique, have been investigated and compared with Ce:Gd{sub 3}Al{sub 2}Ga{sub 3}O{sub 12} ones prepared with identical technology. Improvements in the timing performance of the Mg co-doped samples with respect to Ce:Gd{sub 3}Al{sub 2}Ga{sub 3}O{sub 12} ones have been measured, namely a substantial shortening of the rise time and scintillation decay components and lower afterglow were achieved. In particular, a significantly better coincidence time resolution of 233 ps FWHM, being a fundamental parameter for TOF-PET devices, has been observed in Mg co-doped crystals. The samples have also shown a good radiation tolerance under high doses of γ-rays, making them suitable candidates for applications in harsh radiation environments, such as detectors at future collider experiments.

  16. Fault Tolerant and Optimal Control of Wind Turbines with Distributed High-Speed Generators

    Directory of Open Access Journals (Sweden)

    Urs Giger

    2017-01-01

    Full Text Available In this paper, the control scheme of a distributed high-speed generator system with a total amount of 12 generators and nominal generator speed of 7000 min − 1 is studied. Specifically, a fault tolerant control (FTC scheme is proposed to keep the turbine in operation in the presence of up to four simultaneous generator faults. The proposed controller structure consists of two layers: The upper layer is the baseline controller, which is separated into a partial load region with the generator torque as an actuating signal and the full-load operation region with the collective pitch angle as the other actuating signal. In addition, the lower layer is responsible for the fault diagnosis and FTC characteristics of the distributed generator drive train. The fault reconstruction and fault tolerant control strategy are tested in simulations with several actuator faults of different types.

  17. Dunaliella salina as marine microalga highly tolerant to but a poor remover of cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Folgar, S. [Departamento de Biologia Celular y Molecular, Laboratorio de Microbiologia, Facultad de Ciencias, Universidade da Coruna, Alejandro de la Sota no 1, 15008 La Coruna (Spain); Torres, E., E-mail: torres@udc.es [Departamento de Biologia Celular y Molecular, Laboratorio de Microbiologia, Facultad de Ciencias, Universidade da Coruna, Alejandro de la Sota no 1, 15008 La Coruna (Spain); Perez-Rama, M.; Cid, A.; Herrero, C.; Abalde, J. [Departamento de Biologia Celular y Molecular, Laboratorio de Microbiologia, Facultad de Ciencias, Universidade da Coruna, Alejandro de la Sota no 1, 15008 La Coruna (Spain)

    2009-06-15

    Cadmium tolerance and removal in the marine microalga Dunaliella salina were studied in cultures exposed to different metal concentrations (5-120 mg Cd l{sup -1}) for 96 h. This microalga can be included in the group of microalgal species most tolerant to cadmium due to the high value of EC50 that it possesses (48.9 mg Cd l{sup -1} at 96 h of culture). The greater percentage of cadmium removed was obtained in cultures exposed to 5 mg Cd l{sup -1} at 96 h, but removing only 11.3% of the added cadmium. In all cultures, the quantity of cadmium removed intracellularly was much lower than the bioadsorbed quantity and it was proportional to the sulfhydryl group levels. Both the Freundlich and Langmuir adsorption models were suitable for describing the short-term biosorption of cadmium by living cells of D. salina.

  18. Crystallization of Al-Zr alloys at high cooling rates

    Energy Technology Data Exchange (ETDEWEB)

    Toropova, L.S.; Kamardinkin, A.N.

    1989-01-01

    The nonequilibrium crystallization of Al-Zr alloys containing up to 5 mass pct Zr is investigated by light and electron microscopy and on the basis of lattice spacing and electrical conductivity measurements. A phase diagram of the system is presented. The dependence of the dendritic parameters of Al-Zr alloys on the cooling rate is demonstrated. 10 references.

  19. Analysis of current instabilities of thin AlN/GaN/AlN double heterostructure high electron mobility transistors

    Science.gov (United States)

    Zervos, Ch; Adikimenakis, A.; Bairamis, A.; Kostopoulos, A.; Kayambaki, M.; Tsagaraki, K.; Konstantinidis, G.; Georgakilas, A.

    2016-06-01

    The current instabilities of high electron mobility transistors (HEMTs), based on thin double AlN/GaN/AlN heterostructures (˜0.5 μm total thickness), directly grown on sapphire substrates, have been analyzed and compared for different AlN top barrier thicknesses. The structures were capped by 1 nm GaN and non-passivated 1 μm gate-length devices were processed. Pulsed I-V measurements resulted in a maximum cold pulsed saturation current of 1.4 A mm-1 at a gate-source voltage of +3 V for 3.7 nm AlN thickness. The measured gate and drain lag for 500 ns pulse-width varied between 6%-12% and 10%-18%, respectively. Furthermore, a small increase in the threshold voltage was observed for all the devices, possibly due to the trapping of electrons under the gate contact. The off-state breakdown voltage of V br = 70 V, for gate-drain spacing of 2 μm, was approximately double the value measured for a single AlN/GaN HEMT structure grown on a thick GaN buffer layer. The results suggest that the double AlN/GaN/AlN heterostructures may offer intrinsic advantages for the breakdown and current stability characteristics of high current HEMTs.

  20. High-resistivity nanogranular Co-Al-O films for high-frequency applications

    Science.gov (United States)

    Khalili Amiri, Pedram; Zhuang, Yan; Schellevis, Hugo; Rejaei, Behzad; Vroubel, Marina; Ma, Yue; Burghartz, Joachim N.

    2007-05-01

    This work presents a series of high-resistivity nanogranular Co-Al-O films with maximum resistivity of ˜110mΩcm. The films were deposited using pulsed dc reactive sputtering of a Co72Al28 target in an oxygen/argon ambient. The samples were characterized by scanning electron microscopy (SEM), M-H loop measurements, and s-parameter measurements on microstrip transmission lines with Co-Al-O magnetic cores. The high-frequency magnetic permeability profile was extracted from the microstrip measurements. Reduction of deposition power resulted in resistivity enhancement, as well as reduction of coercivity and permeability. SEM images reveal an average grain size of ˜80nm for films with the highest resistivity.

  1. High breakdown voltage in AlGaN/GaN HEMTs using AlGaN/GaN/AlGaN quantum-well electron-blocking layers.

    Science.gov (United States)

    Lee, Ya-Ju; Yao, Yung-Chi; Huang, Chun-Ying; Lin, Tai-Yuan; Cheng, Li-Lien; Liu, Ching-Yun; Wang, Mei-Tan; Hwang, Jung-Min

    2014-01-01

    In this paper, we numerically study an enhancement of breakdown voltage in AlGaN/GaN high-electron-mobility transistors (HEMTs) by using the AlGaN/GaN/AlGaN quantum-well (QW) electron-blocking layer (EBL) structure. This concept is based on the superior confinement of two-dimensional electron gases (2-DEGs) provided by the QW EBL, resulting in a significant improvement of breakdown voltage and a remarkable suppression of spilling electrons. The electron mobility of 2-DEG is hence enhanced as well. The dependence of thickness and composition of QW EBL on the device breakdown is also evaluated and discussed.

  2. High Antioxidant Activity Facilitates Maintenance of Cell Division in Leaves of Drought Tolerant Maize Hybrids

    Science.gov (United States)

    Avramova, Viktoriya; AbdElgawad, Hamada; Vasileva, Ivanina; Petrova, Alexandra S.; Holek, Anna; Mariën, Joachim; Asard, Han; Beemster, Gerrit T. S.

    2017-01-01

    We studied the impact of drought on growth regulation in leaves of 13 maize varieties with different drought sensitivity and geographic origins (Western Europe, Egypt, South Africa) and the inbred line B73. Combining kinematic analysis of the maize leaf growth zone with biochemical measurements at a high spatial resolution allowed us to examine the correlation between the regulation of the cellular processes cell division and elongation, and the molecular redox-regulation in response to drought. Moreover, we demonstrated differences in the response of the maize lines to mild and severe levels of water deficit. Kinematic analysis indicated that drought tolerant lines experienced less impact on leaf elongation rate due to a smaller reduction of cell production, which, in turn, was due to a smaller decrease of meristem size and number of cells in the leaf meristem. Clear differences in growth responses between the groups of lines with different geographic origin were observed in response to drought. The difference in drought tolerance between the Egyptian hybrids was significantly larger than between the European and South-African hybrids. Through biochemical analyses, we investigated whether antioxidant activity in the growth zone, contributes to the drought sensitivity differences. We used a hierarchical clustering to visualize the patterns of lipid peroxidation, H2O2 and antioxidant concentrations, and enzyme activities throughout the growth zone, in response to stress. The results showed that the lines with different geographic region used different molecular strategies to cope with the stress, with the Egyptian hybrids responding more at the metabolite level and African and the European hybrids at the enzyme level. However, drought tolerance correlated with both, higher antioxidant levels throughout the growth zone and higher activities of the redox-regulating enzymes CAT, POX, APX, and GR specifically in leaf meristems. These findings provide evidence for a link

  3. High Tolerance to Iron Contamination in Lead Halide Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Poindexter, Jeremy R. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Hoye, Robert L. Z. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Nienhaus, Lea [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Kurchin, Rachel C. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Morishige, Ashley E. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Looney, Erin E. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Osherov, Anna [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Correa-Baena, Juan-Pablo [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Lai, Barry [Advanced; Bulović, Vladimir [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Stevanović, Vladan [Colorado School of Mines, 1500; National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States; Bawendi, Moungi G. [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States; Buonassisi, Tonio [Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States

    2017-07-05

    The relationship between charge-carrier lifetime and the tolerance of lead halide perovskite (LHP) solar cells to intrinsic point defects has drawn much attention by helping to explain rapid improvements in device efficiencies. However, little is known about how charge-carrier lifetime and solar cell performance in LHPs are affected by extrinsic defects (i.e., impurities), including those that are common in manufacturing environments and known to introduce deep levels in other semiconductors. Here, we evaluate the tolerance of LHP solar cells to iron introduced via intentional contamination of the feedstock and examine the root causes of the resulting efficiency losses. We find that comparable efficiency losses occur in LHPs at feedstock iron concentrations approximately 100 times higher than those in p-type silicon devices. Photoluminescence measurements correlate iron concentration with nonradiative recombination, which we attribute to the presence of deep-level iron interstitials, as calculated from first-principles, as well as iron-rich particles detected by synchrotron-based X-ray fluorescence microscopy. At moderate contamination levels, we witness prominent recovery of device efficiencies to near-baseline values after biasing at 1.4 V for 60 s in the dark. We theorize that this temporary effect arises from improved charge-carrier collection enhanced by electric fields strengthened from ion migration toward interfaces. Our results demonstrate that extrinsic defect tolerance contributes to high efficiencies in LHP solar cells, which inspires further investigation into potential large-scale manufacturing cost savings as well as the degree of overlap between intrinsic and extrinsic defect tolerance in LHPs and 'perovskite-inspired' lead-free stable alternatives.

  4. Effect of Al2O3 on the Crystallization of Mold Flux for Casting High Al Steel

    Science.gov (United States)

    Zhou, Lejun; Wang, Wanlin; Zhou, Kechao

    2015-06-01

    In order to lower the weight of automotive bodies for better fuel-efficiency and occupant safety, the demand for high Al-containing advanced high strength steel, such as transformation-induced plasticity and twinning-induced plasticity steel, is increasing. However, high aluminum content in steels would tend to significantly affect the properties of mold flux during the continuous casting process. In this paper, a kinetic study of the effect of Al2O3 content on the crystallization behavior of mold flux was conducted by using the single hot thermocouple technique and the Johnson-Mehl-Avrami model combined with the Arrhenius Equation. The results suggested that Al2O3 behaves as an amphoteric oxide in the crystallization process of mold flux. The precipitated phases of mold flux change from cuspidine (Ca4Si2O7F2) into nepheline (NaAlSiO4) and CaF2, and then into gehlenite (Ca2Al2SiO7) with the increase of Al2O3 content. The kinetics study of the isothermal crystallization process indicated that the effective crystallization rate ( k) and Avrami exponent ( n) also first increased and then decreased with the increase of Al2O3 content. The values for the crystallization activation energy of mold flux with different Al2O3 contents were E R0.8A7 = 150.76 ± 17.89 kJ/mol, E R0.8A20 = 136.43 ± 6.48 kJ/mol, E R0.8A30 = 108.63 ± 12.25 kJ/mol and E R0.8A40 = 116.15 ± 8.17 kJ/mol.

  5. Tolerance of two Bifora radians bieb populations to ALS inhibitors in winter wheat

    DEFF Research Database (Denmark)

    Mennan, Husrev; Streibig, Jens Carl; Ngouajio, Mathieu;

    2012-01-01

    BACKGROUND:Bifora radians, an annual weed in winter wheat, is distributed mainly in the Mediterranean area, Asia Minor and the Caucasus. It infests winter-sown crops of the Central Anatolia and Middle Black Sea regions of Turkey. Field experiments in heavily B. radians-infested fields were...... be important to establish tools demonstrating when farmers recognise loss of herbicide efficacy. There has been no indication of evolution of resistant biotypes so far, but continuous spraying favours biotypes with increased levels of tolerance. Copyright © 2011 Society of Chemical Industry....

  6. Strong tolerance of blue-green alga Microcystis flos-aquae to very high pressure

    Science.gov (United States)

    Ono, F.; Nishihira, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Saigusa, M.; Matsushima, Y.; Yamazaki, D.; Ito, E.

    2015-09-01

    It was shown in our previous reports that a few spores of moss Venturiella could tolerate the very high pressure of 20 GPa for 30 min and germinated a protonema to the length of 30 μm. However, these spores did not grow any further, and disappeared at around 30 days of incubation after seeded. On the other hand, colonies of blue-green alga Microcystis flos-aquae came to appear about 76 days after the moss spores were seeded. Many of these colonies appeared at the places where the moss spores had disappeared. These colonies were formed by the algae that had adhered to the spore cases of the moss and survived after exposure to the very high pressure of 20 GPa. Though the appearance of the colonies of high pressure exposed algae was delayed by about 50 days compared with that of the control group which was not exposed to high pressure, there seems no difference in their shape and color from those of the control group. The pressure tolerance of blue-green alga is found to be enormously strong, and it can survive after exposure to the high pressure which corresponds to the depth of about 550-600 km from the surface of the Earth, just above the lower mantle.

  7. High PAE high reliability AlN/GaN double heterostructure

    Science.gov (United States)

    Medjdoub, F.; Zegaoui, M.; Linge, A.; Grimbert, B.; Silvestri, R.; Meneghini, M.; Meneghesso, G.; Zanoni, E.

    2015-11-01

    We report on AlN/GaN double heterostructures for high frequency applications. 600 h preliminary reliability assessment has been performed on these emerging RF devices, showing promising millimeter-wave 100 nm gate length GaN-on-Si device stability for the first time. A 150 nm AlN/GaN double heterostructure has been developed and evaluated on SiC substrate. State-of-the-art CW power-added-efficiencies (PAE) up to 40 GHz have been achieved on ultrathin barrier (6 nm) GaN devices while operating at a drain bias exceeding 30 V.

  8. High Speed Operation and Testing of a Fault Tolerant Magnetic Bearing

    Science.gov (United States)

    DeWitt, Kenneth; Clark, Daniel

    2004-01-01

    Research activities undertaken to upgrade the fault-tolerant facility, continue testing high-speed fault-tolerant operation, and assist in the commission of the high temperature (1000 degrees F) thrust magnetic bearing as described. The fault-tolerant magnetic bearing test facility was upgraded to operate to 40,000 RPM. The necessary upgrades included new state-of-the art position sensors with high frequency modulation and new power edge filtering of amplifier outputs. A comparison study of the new sensors and the previous system was done as well as a noise assessment of the sensor-to-controller signals. Also a comparison study of power edge filtering for amplifier-to-actuator signals was done; this information is valuable for all position sensing and motor actuation applications. After these facility upgrades were completed, the rig is believed to have capabilities for 40,000 RPM operation, though this has yet to be demonstrated. Other upgrades included verification and upgrading of safety shielding, and upgrading control algorithms. The rig will now also be used to demonstrate motoring capabilities and control algorithms are in the process of being created. Recently an extreme temperature thrust magnetic bearing was designed from the ground up. The thrust bearing was designed to fit within the existing high temperature facility. The retrofit began near the end of the summer, 04, and continues currently. Contract staff authored a NASA-TM entitled "An Overview of Magnetic Bearing Technology for Gas Turbine Engines", containing a compilation of bearing data as it pertains to operation in the regime of the gas turbine engine and a presentation of how magnetic bearings can become a viable candidate for use in future engine technology.

  9. High-Temperature CO2 Sorption on Hydrotalcite Having a High Mg/Al Molar Ratio.

    Science.gov (United States)

    Kim, Suji; Jeon, Sang Goo; Lee, Ki Bong

    2016-03-09

    Hydrotalcites having a Mg/Al molar ratio between 3 and 30 have been synthesized as promising high-temperature CO2 sorbents. The existence of NaNO3 in the hydrotalcite structure, which originates from excess magnesium nitrate in the precursor, markedly increases CO2 sorption uptake by hydrotalcite up to the record high value of 9.27 mol kg(-1) at 240 °C and 1 atm CO2.

  10. High-temperature oxidation behavior of Al2O3/TiAl matrix composite in air

    Institute of Scientific and Technical Information of China (English)

    AI TaoTao; WANG Fen; FENG XiaoMing

    2009-01-01

    improve the oxidation resistance. Moreover, the multi-structure of the TiO2+Al2O3 mixed layer decreases the indiffusion of oxygen ions and also avails to improve the high temperature oxidation resistance of the as-sintered composites.

  11. Manufacture of Raney Ni catalyst with metastable Ni2Al3 by high-energy milling

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Ni-Al alloy containing Cr, Fe additives were prepared as Raney Ni catalyst by high energy milling. The size and surface state of Ni-Al alloy powder were studied by particle size analyzer and sanning electron microscopy, the structure was analyzed by XRD and Mossbauer methods. The results showed that after a high-energy milling (HEM), the Ni-Al alloy transforms to a nano-scale NiAl structure with rich Al. Byannealing the alloy, a metastable Ni2Al3 phase can be obtained.

  12. High-Speed Radiation Tolerant Avalanche Photodiodes Based on InGaN for Space Altimeter Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High-performance, radiation-tolerant detectors are required for the time-of-flight laser based rangefinders. Avalanche photodiodes (APDs) are conventionally chosen...

  13. Multicharacterization approach for studying InAl(Ga)N/Al(Ga)N/GaN heterostructures for high electron mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Naresh-Kumar, G., E-mail: naresh.gunasekar@strath.ac.uk; Trager-Cowan, C. [Dept of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Vilalta-Clemente, A.; Morales, M.; Ruterana, P. [CIMAP UMR 6252 CNRS-ENSICAEN-CEA-UCBN 14050 Caen Cedex (France); Pandey, S.; Cavallini, A.; Cavalcoli, D. [Dipartimento di Fisica Astronomia, Università di Bologna, 40127 Bologna (Italy); Skuridina, D.; Vogt, P.; Kneissl, M. [Institute of Solid State Physics, Technical University Berlin, 10623 Berlin (Germany); Behmenburg, H.; Giesen, C.; Heuken, M. [AIXTRON SE, Kaiserstr. 98, 52134 Herzogenrath (Germany); Gamarra, P.; Di Forte-Poisson, M. A. [Thales Research and Technology, III-V Lab, 91460 Marcoussis (France); Patriarche, G. [LPN, Route de Nozay, 91460 Marcoussis (France); Vickridge, I. [Institut des NanoSciences, Université Pierre et Marie Curie, 75015 Paris (France)

    2014-12-15

    We report on our multi–pronged approach to understand the structural and electrical properties of an InAl(Ga)N(33nm barrier)/Al(Ga)N(1nm interlayer)/GaN(3μm)/ AlN(100nm)/Al{sub 2}O{sub 3} high electron mobility transistor (HEMT) heterostructure grown by metal organic vapor phase epitaxy (MOVPE). In particular we reveal and discuss the role of unintentional Ga incorporation in the barrier and also in the interlayer. The observation of unintentional Ga incorporation by using energy dispersive X–ray spectroscopy analysis in a scanning transmission electron microscope is supported with results obtained for samples with a range of AlN interlayer thicknesses grown under both the showerhead as well as the horizontal type MOVPE reactors. Poisson–Schrödinger simulations show that for high Ga incorporation in the Al(Ga)N interlayer, an additional triangular well with very small depth may be exhibited in parallel to the main 2–DEG channel. The presence of this additional channel may cause parasitic conduction and severe issues in device characteristics and processing. Producing a HEMT structure with InAlGaN as the barrier and AlGaN as the interlayer with appropriate alloy composition may be a possible route to optimization, as it might be difficult to avoid Ga incorporation while continuously depositing the layers using the MOVPE growth method. Our present work shows the necessity of a multicharacterization approach to correlate structural and electrical properties to understand device structures and their performance.

  14. Multicharacterization approach for studying InAl(GaN/Al(GaN/GaN heterostructures for high electron mobility transistors

    Directory of Open Access Journals (Sweden)

    G. Naresh-Kumar

    2014-12-01

    Full Text Available We report on our multi–pronged approach to understand the structural and electrical properties of an InAl(GaN(33nm barrier/Al(GaN(1nm interlayer/GaN(3μm/ AlN(100nm/Al2O3 high electron mobility transistor (HEMT heterostructure grown by metal organic vapor phase epitaxy (MOVPE. In particular we reveal and discuss the role of unintentional Ga incorporation in the barrier and also in the interlayer. The observation of unintentional Ga incorporation by using energy dispersive X–ray spectroscopy analysis in a scanning transmission electron microscope is supported with results obtained for samples with a range of AlN interlayer thicknesses grown under both the showerhead as well as the horizontal type MOVPE reactors. Poisson–Schrödinger simulations show that for high Ga incorporation in the Al(GaN interlayer, an additional triangular well with very small depth may be exhibited in parallel to the main 2–DEG channel. The presence of this additional channel may cause parasitic conduction and severe issues in device characteristics and processing. Producing a HEMT structure with InAlGaN as the barrier and AlGaN as the interlayer with appropriate alloy composition may be a possible route to optimization, as it might be difficult to avoid Ga incorporation while continuously depositing the layers using the MOVPE growth method. Our present work shows the necessity of a multicharacterization approach to correlate structural and electrical properties to understand device structures and their performance.

  15. The ability of Typha domingensis to accumulate and tolerate high concentrations of Cr, Ni, and Zn.

    Science.gov (United States)

    Mufarrege, M M; Hadad, H R; Di Luca, G A; Maine, M A

    2015-01-01

    The tolerance and removal efficiency of Typha domingensis exposed to high concentrations of Cr, Ni, and Zn in single and combined treatments were studied. Sediment and two plants were disposed in each plastic reactor. The treatments were 100 and 500 mg L(-1) of Cr, Ni, and Zn (single solutions); 100 mg L(-1) Cr + Ni + Zn (multi-metal solutions) and 500 mg L(-1) Cr + Ni + Zn (multi-metal solutions); and a control. Even though the concentrations studied were extremely high, simulating an accidental metal dump, the three metals were efficiently removed from water. The highest removal was registered for Cr. The presence of other metals favored Cr and did not favor Ni and Zn removal from water. After 25 days, senescence and chlorosis of plants were observed in Ni and Comb500 treatments, while Cr and Zn only caused growth inhibition. T. domingensis accumulated high metal concentrations in tissues. The roots showed higher metal concentration than submerged parts of leaves. Cr translocation to aerial parts was enhanced by the presence of Ni and Zn. Our results demonstrate that in the case of an accidental dump of high Cr, Ni, and Zn concentrations, a wetland system dominated by T. domingensis is able to retain metals, and the macrophyte is able to tolerate them the time necessary to remove them from water. Thus, the environment will be preserved since the wetland would act as a cushion.

  16. Predictive factors of head and neck squamous cell carcinoma patient tolerance to high-dose cisplatin in concurrent chemoradiotherapy

    OpenAIRE

    Nakano, Kenji; SATO, YASUYOSHI; TOSHIYASU, TAKASHI; SATO, YUKIKO; INAGAKI, LINA; Tomomatsu, Junichi; Sasaki, Toru; SHIMBASHI, WATARU; FUKUSHIMA, HIROFUMI; YONEKAWA, HIROYUKI; Mitani,Hiroki; Kawabata, Kazuyoshi; Takahashi, Shunji

    2015-01-01

    Although high-dose cisplatin is the standard regimen of concurrent chemoradiotherapy (CCRT) for locally advanced head and neck squamous cell carcinoma (HNSCC), varying levels of patient tolerance towards cisplatin have been reported, and the predictive factors of cisplatin tolerance remain to be elucidated. The present study retrospectively reviewed newly diagnosed HNSCC patients who received CCRT. Cisplatin (80 mg/m2) was administered every 3 weeks. The proportion of high-dose cisplatin-tole...

  17. Polarization-independent high-index contrast grating and its fabrication tolerances

    DEFF Research Database (Denmark)

    Ikeda, Kazuhiro; Takeuchi, Kazuma; Takayose, Kentaro

    2013-01-01

    A polarization-independent, high-index contrast grating (HCG) with a single layer of cross stripes allowing simple fabrication is proposed. Since the cross stripes structure can be suspended in air by selectively wet-etching the layer below, all the layers can be grown at once when implemented...... also investigated the fabrication tolerances of the structure and found that, assuming careful optimizations of electron beam lithography for the precise grating width and dry-etching for the vertical sidewall, the suggested polarization-independent HCG can be fabricated using standard technologies....

  18. High Temperature, Permanent Magnet Biased, Fault Tolerant, Homopolar Magnetic Bearing Development

    Science.gov (United States)

    Palazzolo, Alan; Tucker, Randall; Kenny, Andrew; Kang, Kyung-Dae; Ghandi, Varun; Liu, Jinfang; Choi, Heeju; Provenza, Andrew

    2008-01-01

    This paper summarizes the development of a magnetic bearing designed to operate at 1,000 F. A novel feature of this high temperature magnetic bearing is its homopolar construction which incorporates state of the art high temperature, 1,000 F, permanent magnets. A second feature is its fault tolerance capability which provides the desired control forces with over one-half of the coils failed. The construction and design methodology of the bearing is outlined and test results are shown. The agreement between a 3D finite element, magnetic field based prediction for force is shown to be in good agreement with predictions at room and high temperature. A 5 axis test rig will be complete soon to provide a means to test the magnetic bearings at high temperature and speed.

  19. Frequency Comparison of Two High-Accuracy Al+ Optical Clocks

    CERN Document Server

    Chou, C -W; Koelemeij, J C J; Wineland, D J; Rosenband, T

    2009-01-01

    We have constructed an optical clock with a fractional frequency inaccuracy of 8.6e-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser-cool the Al+ ion and detect its quantum state. The frequency of the 1S0->3P0 clock transition is compared to that of a previously constructed Al+ optical clock with a statistical measurement uncertainty of 7.0e-18. The two clocks exhibit a relative stability of 2.8e-15/ sqrt(tau), and a fractional frequency difference of -1.8e-17, consistent with the accuracy limit of the older clock.

  20. Frequency Comparison of Two High-Accuracy Al+ Optical Clocks

    Science.gov (United States)

    Chou, C. W.; Hume, D. B.; Koelemeij, J. C. J.; Wineland, D. J.; Rosenband, T.

    2010-02-01

    We have constructed an optical clock with a fractional frequency inaccuracy of 8.6×10-18, based on quantum logic spectroscopy of an Al+ ion. A simultaneously trapped Mg+ ion serves to sympathetically laser cool the Al+ ion and detect its quantum state. The frequency of the S01↔P03 clock transition is compared to that of a previously constructed Al+ optical clock with a statistical measurement uncertainty of 7.0×10-18. The two clocks exhibit a relative stability of 2.8×10-15τ-1/2, and a fractional frequency difference of -1.8×10-17, consistent with the accuracy limit of the older clock.

  1. An essential factor for high Mg2+ tolerance of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Joshua Armitano

    2016-11-01

    Full Text Available Internal bacterial concentration of Mg2+, the most abundant divalent cation in living cells, is estimated to be in the single millimolar range. However, many bacteria will thrive in media with only micromolars of Mg2+, by using a range of intensely studied and highly efficient import mechanisms, as well as in media with very high magnesium concentration, presumably mediated by currently unknown export mechanisms. Staphylococcus aureus has a particularly high Mg2+ tolerance for a pathogen, growing unimpaired in up to 770 mM Mg2+, and we here identify SA0657, a key factor in this tolerance. The predicted domain structure of SA0657 is shared with a large number of proteins in bacteria, archaea and even eukarya, for example CorB from Salmonella and the human CNNM protein family. One of the shared domains, a CBS pair potentially involved in Mg2+ sensing, contains the conserved Glycine326 which we establish to be a key residue for SA0657 function. In light of our findings, we propose the name MpfA, Magnesium Protection Factor A, for SA0657.

  2. Multiple PLDs required for high salinity and water deficit tolerance in plants.

    Science.gov (United States)

    Bargmann, Bastiaan O R; Laxalt, Ana M; ter Riet, Bas; van Schooten, Bas; Merquiol, Emmanuelle; Testerink, Christa; Haring, Michel A; Bartels, Dorothea; Munnik, Teun

    2009-01-01

    High salinity and drought have received much attention because they severely affect crop production worldwide. Analysis and comprehension of the plant's response to excessive salt and dehydration will aid in the development of stress-tolerant crop varieties. Signal transduction lies at the basis of the response to these stresses, and numerous signaling pathways have been implicated. Here, we provide further evidence for the involvement of phospholipase D (PLD) in the plant's response to high salinity and dehydration. A tomato (Lycopersicon esculentum) alpha-class PLD, LePLDalpha1, is transcriptionally up-regulated and activated in cell suspension cultures treated with salt. Gene silencing revealed that this PLD is indeed involved in the salt-induced phosphatidic acid production, but not exclusively. Genetically modified tomato plants with reduced LePLDalpha1 protein levels did not reveal altered salt tolerance. In Arabidopsis (Arabidopsis thaliana), both AtPLDalpha1 and AtPLDdelta were found to be activated in response to salt stress. Moreover, pldalpha1 and plddelta single and double knock-out mutants exhibited enhanced sensitivity to high salinity stress in a plate assay. Furthermore, we show that both PLDs are activated upon dehydration and the knock-out mutants are hypersensitive to hyperosmotic stress, displaying strongly reduced growth.

  3. High Temperature Steam Oxidation Testing of Candidate Accident Tolerant Fuel Cladding Materials

    Energy Technology Data Exchange (ETDEWEB)

    Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nelson, Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Scott [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parkison, Adam [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2013-12-23

    The Fuel Cycle Research and Development (FCRD) program’s Advanced Fuels Campaign has initiated a multifold effort aimed at facilitating development of accident tolerant fuels in order to overcome the inherent shortcomings of light water reactor (LWR) fuels when exposed to beyond design basis accident conditions. The campaign has invested in development of experimental infrastructure within the Department of Energy complex capable of chronicling the performance of a wide range of concepts under prototypic accident conditions. This report summarizes progress made at Oak Ridge National Laboratory (ORNL) and Los Alamos National Laboratory (LANL) in FY13 toward these goals. Alternative fuel cladding materials to Zircaloy for accident tolerance and a significantly extended safety margin requires oxidation resistance to steam or steam-H2 environments at ≥1200°C for short times. At ORNL, prior work focused attention on SiC, FeCr and FeCrAl as the most promising candidates for further development. Also, it was observed that elevated pressure and H2 additions had minor effects on alloy steam oxidation resistance, thus, 1 bar steam was adequate for screening potential candidates. Commercial Fe-20Cr-5Al alloys remain protective up to 1475°C in steam and CVD SiC up to 1700°C in steam. Alloy development has focused on Fe-Cr-Mn-Si-Y and Fe-Cr-Al-Y alloys with the aluminaforming alloys showing more promise. At 1200°C, ferritic binary Fe-Cr alloys required ≥25% Cr to be protective for this application. With minor alloy additions to Fe-Cr, more than 20%Cr was still required, which makes the alloy susceptible to α’ embrittlement. Based on current results, a Fe-15Cr-5Al-Y composition was selected for initial tube fabrication and welding for irradiation experiments in FY14. Evaluations of chemical vapor deposited (CVD) SiC were conducted up to 1700°C in steam. The reaction of H2O with the alumina reaction tube at 1700°C resulted in Al(OH)3

  4. Nrf2 deficiency improves glucose tolerance in mice fed a high-fat diet

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu-Kun Jennifer; Wu, Kai Connie; Liu, Jie; Klaassen, Curtis D., E-mail: cklaasse@kumc.edu

    2012-11-01

    Nrf2, a master regulator of intracellular redox homeostasis, is indicated to participate in fatty acid metabolism in liver. However, its role in diet-induced obesity remains controversial. In the current study, genetically engineered Nrf2-null, wild-type (WT), and Nrf2-activated, Keap1-knockdown (K1-KD) mice were fed either a control or a high-fat Western diet (HFD) for 12 weeks. The results indicate that the absence or enhancement of Nrf2 activity did not prevent diet-induced obesity, had limited effects on lipid metabolism, but affected blood glucose homeostasis. Whereas the Nrf2-null mice were resistant to HFD-induced glucose intolerance, the Nrf2-activated K1-KD mice exhibited prolonged elevation of circulating glucose during a glucose tolerance test even on the control diet. Feeding a HFD did not activate the Nrf2 signaling pathway in mouse livers. Fibroblast growth factor 21 (Fgf21) is a liver-derived anti-diabetic hormone that exerts glucose- and lipid-lowering effects. Fgf21 mRNA and protein were both elevated in livers of Nrf2-null mice, and Fgf21 protein was lower in K1-KD mice than WT mice. The inverse correlation between Nrf2 activity and hepatic expression of Fgf21 might explain the improved glucose tolerance in Nrf2-null mice. Furthermore, a more oxidative cellular environment in Nrf2-null mice could affect insulin signaling in liver. For example, mRNA of insulin-like growth factor binding protein 1, a gene repressed by insulin in hepatocytes, was markedly elevated in livers of Nrf2-null mice. In conclusion, genetic alteration of Nrf2 does not prevent diet-induced obesity in mice, but deficiency of Nrf2 improves glucose homeostasis, possibly through its effects on Fgf21 and/or insulin signaling. -- Highlights: ► Nrf2 deficiency improves glucose tolerance in mice fed a high-fat diet. ► The anti-diabetic hormone, Fgf21, is highly expressed in livers of Nrf2-null mice. ► The absence of Nrf2 increases the insulin-regulated Igfbp-1 mRNA in liver.

  5. Molecular approaches unravel the mechanism of acid soil tolerance in plants

    Institute of Scientific and Technical Information of China (English)

    Miao; Bian; Meixue; Zhou; Dongfa; Sun; Chengdao; Li

    2013-01-01

    Acid soil is a worldwide problem to plant production. Acid toxicity is mainly caused by a lack of essential nutrients in the soil and excessive toxic metals in the plant root zone. Of the toxic metals, aluminum(Al) is the most prevalent and most toxic. Plant species have evolved to variable levels of tolerance to aluminum enabling breeding of high Al-tolerant cultivars.Physiological and molecular approaches have revealed some mechanisms of Al toxicity in higher plants. Mechanisms of plant tolerance to Al stress include: 1) exclusion of Al from the root tips, and 2) absorbance, but tolerance of Al in root cells. Organic acid exudation to chelate Al is a feature shared by many higher plants. The future challenge for Al tolerance studies is the identification of novel tolerance mechanisms and the combination of different mechanisms to achieve higher tolerance. Molecular approaches have led to significant progress in explaining mechanisms and detection of genes responsible for Al tolerance.Gene-specific molecular markers offer better options for marker-assisted selection in breeding programs than linked marker strategies. This paper mainly focuses on recent progress in the use of molecular approaches in Al tolerance research.

  6. Crop physiological responses to high temperature stress. II. Tolerance and agronomic treatment.

    Directory of Open Access Journals (Sweden)

    Néstor Felipe Chaves-Barrantes

    2016-12-01

    Full Text Available The objective of this review was to describe plant responses and tolerance mechanisms to thermal stress, as well as the use of agronomic practices to mitigate the effects of high temperature stress on crops. The energy balance of leaves and canopies is presented as a link between plant and air temperature. The effects of high temperatures on water relations, photosynthesis and assimilate partitioning, and the morphological and phenological responses of some crops are described. Response agronomy is presented as a means for the prevention and remediation of thermal stress, which is approached form the perspective of plant breeding, agronomic management, and several pharmaceutical and horticultural practices. Some agronomic practices utilized to reduce the negative effects of high temperature stress on crops are described, such as the use of ground covers, natural or arti cial shade, and the application of growth regulators, plant protectants and other products of the modern pharmaceutical industry.

  7. Radiation tolerant fiber optic humidity sensors for High Energy Physics applications

    CERN Document Server

    Berruti, Gaia Maria; Cusano, Andrea

    This work is devoted to the development of fiber optic humidity sensors to be applied in high-energy physics applications and in particular in experiments currently running at CERN. The high radiation level resulting from the operation of the accelerator at full luminosity can cause serious performance deterioration of the silicon sensors which are responsible for the particle tracking. To increase their lifetime, the sensors must be kept cold at temperatures below 0 C. At such low temperatures, any condensation risk has to be prevented and a precise thermal and hygrometric control of the air filling and surrounding the tracker detector cold volumes is mandatory. The technologies proposed at CERN for relative humidity monitoring are mainly based on capacitive sensing elements which are not designed with radiation resistance characteristic. In this scenario, fiber optic sensors seem to be perfectly suitable. Indeed, the fiber itself, if properly selected, can tolerate a very high level of radiation, optical fi...

  8. Mutation-Screening of Pleurotus Ferulae with High Temperature Tolerance by Nitrogen Ion Implantation

    Science.gov (United States)

    Chen, Henglei; Wan, Honggui; Zhang, Jun; Zeng, Xianxian

    2008-08-01

    In order to obtain Pleurotus ferulae with high temperature tolerance, conidiophores of wild type strain ACK were implanted with nitrogen ions in energy of 5 ~15 keV and dose of 1.5 × 1015 ~ 1.5 × 1016 cm-2, and a mutant CGMCC1763 was isolated subsequently through thermotolerant screening method. It was found that during riper period the surface layer mycelium of the mutant in mushroom bag wasn't aging neither grew tegument even above 30° C. The mycelium endurable temperature of the mutant was increased by 5°C compared to that of the wild type strain. The fruiting bodies growth temperature of the mutant was 18 ~22°C in daytime and 8~14°C at night. The highest growth temperature of fruiting bodies of the mutant was increased about 7°C w.r.t. that of original strain. Through three generations investigations, it was found that the mutant CGMCC1763 was stable with high temperature tolerance.

  9. Design of two digital radiation tolerant integrated circuits for high energy physics experiments data readout

    CERN Document Server

    Bonacini, Sandro

    2003-01-01

    High Energy Physics research (HEP) involves the design of readout electron- ics for its experiments, which generate a high radiation ¯eld in the detectors. The several integrated circuits placed in the future Large Hadron Collider (LHC) experiments' environment have to resist the radiation and carry out their normal operation. In this thesis I will describe in detail what, during my 10-months partic- ipation in the digital section of the Microelectronics group at CERN, I had the possibility to work on: - The design of a radiation-tolerant data readout digital integrated cir- cuit in a 0.25 ¹m CMOS technology, called \\the Kchip", for the CMS preshower front-end system. This will be described in Chapter 3. - The design of a radiation-tolerant SRAM integrated circuit in a 0.13 ¹m CMOS technology, for technology radiation testing purposes and fu- ture applications in the HEP ¯eld. The SRAM will be described in Chapter 4. All the work has carried out under the supervision and with the help of Dr. Kostas Klouki...

  10. Personalized metabolomics for predicting glucose tolerance changes in sedentary women after high-intensity interval training.

    Science.gov (United States)

    Kuehnbaum, Naomi L; Gillen, Jenna B; Gibala, Martin J; Britz-McKibbin, Philip

    2014-08-28

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear. Herein, multi-segment injection capillary electrophoresis-mass spectrometry is used as a high-throughput platform in metabolomics to assess dynamic responses of overweight/obese women (BMI > 25, n = 11) to standardized oral glucose tolerance tests (OGTTs) performed before and after a 6-week HIIT intervention. Various statistical methods were used to classify plasma metabolic signatures associated with post-prandial glucose and/or training status when using a repeated measures/cross-over study design. Branched-chain/aromatic amino acids and other intermediates of urea cycle and carnitine metabolism decreased over time in plasma after oral glucose loading. Adaptive exercise-induced changes to plasma thiol redox and orthinine status were measured for trained subjects while at rest in a fasting state. A multi-linear regression model was developed to predict changes in glucose tolerance based on a panel of plasma metabolites measured for naïve subjects in their untrained state. Since treatment outcomes to physical activity are variable between-subjects, prognostic markers offer a novel approach to screen for potential negative responders while designing lifestyle modifications that maximize the salutary benefits of exercise for diabetes prevention on an individual level.

  11. The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Akira; Kawahara, Nobuhiro [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Takagi, Hiroshi, E-mail: hiro@bs.naist.jp [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer NO is produced from L-arginine in response to elevated temperature in yeast. Black-Right-Pointing-Pointer Tah18 was first identified as the yeast protein involved in NO synthesis. Black-Right-Pointing-Pointer Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe-S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

  12. Chloroplast movement behavior varies widely among species and does not correlate with high light stress tolerance.

    Science.gov (United States)

    Königer, Martina; Bollinger, Nicole

    2012-08-01

    It is well known that chloroplasts move in response to changes in blue light intensity in order to optimize light interception, however, little is known about interspecific variation and the relative importance of this mechanism for the high light stress tolerance of plants. We characterized chloroplast movement behavior as changes in light transmission through a leaf in a variety of species ranging from ferns to monocots and eudicots and found a wide spectrum of responses. Most species exhibited a distinct accumulation response compared to the dark positioning, and all species showed a distinct avoidance response. The speed with which transmission values changed during the avoidance response was consistently faster than that during the accumulation response and speeds varied greatly between species. Plants thriving in higher growth light intensities showed greater degrees of accumulation responses and faster changes in transmission than those that prefer lower light intensities. In some species, the chloroplasts on both the adaxial and abaxial leaf surfaces changed their positioning in response to light, while in other species only the chloroplasts on one leaf side responded. No correlation was found between high light stress tolerance and the speed or degree of transmission changes, indicating that plants can compensate for slow and limited transmission changes using other photoprotective mechanisms.

  13. Mutation-Screening of Pleurotus Ferulae with High Temperature Tolerance by Nitrogen Ion Implantation

    Institute of Scientific and Technical Information of China (English)

    CHEN Henglei; WAN Honggui; ZHANG Jun; ZENG Xianxian

    2008-01-01

    In order to obtain Pleurotus ferulae with high temperature tolerance, conidiophores of wild type strain ACK were implanted with nitrogen ions in energy of 5 ~15 keV and dose of 1.5×1015 ~ 1.5 × 10 16 cm-2, and a mutant CGMCC1763 was isolated subsequently through ther-motolerant screening method. It was found that during riper period the surface layer mycelium of the mutant in mushroom bag wasn't aging neither grew tegument even above 30℃. The mycelium endurable temperature of the mutant was increased by 5℃ compared to that of the wild type strain. The fruiting bodies growth temperature of the mutant was 18~22℃ in daytime and 8~14℃ at night. The highest growth temperature of fruiting bodies of the mutant was increased about 7℃ w.r.t, that of original strain. Through three generations investigations, it was found that the mutant CGMCC1763 was stable with high temperature tolerance.

  14. Prueba oral de tolerancia al almidón del grano de avena en ponies (Oral oats grain starch tolerance test in ponies

    Directory of Open Access Journals (Sweden)

    Perrone, G.

    2011-10-01

    Full Text Available ResumenSe efectuó una Prueba Oral de Tolerancia al Almidón del grano de Avena en ponies, para desarrollar una curva de glucemia propia de estas razas, compararla con las curvas de glucemia de equinos de mayor alzada, consumiendo pasturas o dietas mixtas de forrajes y concentrados, y observar si algún pony pudiera ser considerado unvalor atípico.SummaryAn oral oats grain starch tolerance test in ponies was carried out to develop a glycaemic curve specific to these breeds, compared it with glycaemic curves of larger height horses, pasture fed or forage and concentrates fed, and see if any pony could be considered outlier.

  15. Coordinated Fault-Tolerance for High-Performance Computing Final Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Dhabaleswar Kumar [The Ohio State University; Beckman, Pete

    2011-07-28

    With the Coordinated Infrastructure for Fault Tolerance Systems (CIFTS, as the original project came to be called) project, our aim has been to understand and tackle the following broad research questions, the answers to which will help the HEC community analyze and shape the direction of research in the field of fault tolerance and resiliency on future high-end leadership systems. Will availability of global fault information, obtained by fault information exchange between the different HEC software on a system, allow individual system software to better detect, diagnose, and adaptively respond to faults? If fault-awareness is raised throughout the system through fault information exchange, is it possible to get all system software working together to provide a more comprehensive end-to-end fault management on the system? What are the missing fault-tolerance features that widely used HEC system software lacks today that would inhibit such software from taking advantage of systemwide global fault information? What are the practical limitations of a systemwide approach for end-to-end fault management based on fault awareness and coordination? What mechanisms, tools, and technologies are needed to bring about fault awareness and coordination of responses on a leadership-class system? What standards, outreach, and community interaction are needed for adoption of the concept of fault awareness and coordination for fault management on future systems? Keeping our overall objectives in mind, the CIFTS team has taken a parallel fourfold approach. Our central goal was to design and implement a light-weight, scalable infrastructure with a simple, standardized interface to allow communication of fault-related information through the system and facilitate coordinated responses. This work led to the development of the Fault Tolerance Backplane (FTB) publish-subscribe API specification, together with a reference implementation and several experimental implementations on top of

  16. A multi-layer robust adaptive fault tolerant control system for high performance aircraft

    Science.gov (United States)

    Huo, Ying

    Modern high-performance aircraft demand advanced fault-tolerant flight control strategies. Not only the control effector failures, but the aerodynamic type failures like wing-body damages often result in substantially deteriorate performance because of low available redundancy. As a result the remaining control actuators may yield substantially lower maneuvering capabilities which do not authorize the accomplishment of the air-craft's original specified mission. The problem is to solve the control reconfiguration on available control redundancies when the mission modification is urged to save the aircraft. The proposed robust adaptive fault-tolerant control (RAFTC) system consists of a multi-layer reconfigurable flight controller architecture. It contains three layers accounting for different types and levels of failures including sensor, actuator, and fuselage damages. In case of the nominal operation with possible minor failure(s) a standard adaptive controller stands to achieve the control allocation. This is referred to as the first layer, the controller layer. The performance adjustment is accounted for in the second layer, the reference layer, whose role is to adjust the reference model in the controller design with a degraded transit performance. The upmost mission adjust is in the third layer, the mission layer, when the original mission is not feasible with greatly restricted control capabilities. The modified mission is achieved through the optimization of the command signal which guarantees the boundedness of the closed-loop signals. The main distinguishing feature of this layer is the the mission decision property based on the current available resources. The contribution of the research is the multi-layer fault-tolerant architecture that can address the complete failure scenarios and their accommodations in realities. Moreover, the emphasis is on the mission design capabilities which may guarantee the stability of the aircraft with restricted post

  17. High prevalence of abnormal circadian blood pressure regulation and impaired glucose tolerance in adults with hypopituitarism.

    Science.gov (United States)

    Krzyzanowska, K; Schnack, C; Mittermayer, F; Kopp, H P; Hofer, M; Kann, T; Schernthaner, G

    2005-09-01

    Patients with hypopituitarism have an increased mortality from cardiovascular events. Reduced nocturnal blood pressure decline (non-dipping) and impaired glucose tolerance are considered as cardiovascular risk factors. To evaluate the role of these risk factors in patients with hypopituitarism we determined the 24-hour blood pressure regulation and glucose tolerance status in hypopituitary patients with and without growth hormone (GH) deficiency. Sixty-one hypopituitary subjects 5 +/- 3 years after brain surgery because of macroadenoma, 61 patients with type 2 diabetes mellitus (T2DM), and 20 healthy controls were included. Forty-four hypopituitary patients were GH deficient and 28 of these on GH treatment. Non-dipping was observed in 41 % (n = 7) of hypopituitary subjects with normal GH release, in 46 % (n = 13) of patients on GH therapy, and in 69 % (n = 11) of untreated GH deficient patients. Untreated GH deficient patients had a higher systolic night/day ratio (1.00 +/- 0.03) compared to non GH deficient (0.92 +/- 0.02; p < 0.02) and GH treated hypopituitary patients (0.93 +/- 0.01; p < 0.02). The rate of non-dipping in hypopituitarism was comparable to that in T2DM. Pathologic glucose tolerance was diagnosed in 30 % of the hypopituitary patients. The prevalence of non-dipping was independent of glucose metabolism in hypopituitary patients. All controls had normal night time blood pressure fall and glucose metabolism. The high prevalence of nocturnal non-dipping and glucose intolerance detected in this cohort might contribute to the increased cardiovascular risk of hypopituitary patients.

  18. Search for genes responsible for the remarkably high acetic acid tolerance of a Zygosaccharomyces bailii-derived interspecies hybrid strain.

    Science.gov (United States)

    Palma, Margarida; Roque, Filipa de Canaveira; Guerreiro, Joana Fernandes; Mira, Nuno Pereira; Queiroz, Lise; Sá-Correia, Isabel

    2015-12-16

    Zygosaccharomyces bailii is considered the most problematic acidic food spoilage yeast species due to its exceptional capacity to tolerate high concentrations of weak acids used as fungistatic preservatives at low pH. However, the mechanisms underlying its intrinsic remarkable tolerance to weak acids remain poorly understood. The identification of genes and mechanisms involved in Z. bailii acetic acid tolerance was on the focus of this study. For this, a genomic library from the highly acetic acid tolerant hybrid strain ISA1307, derived from Z. bailii and a closely related species and isolated from a sparkling wine production plant, was screened for acetic acid tolerance genes. This screen was based on the transformation of an acetic acid susceptible Saccharomyces cerevisiae mutant deleted for the gene encoding the acetic acid resistance determinant transcription factor Haa1. The expression of 31 different DNA inserts from ISA1307 strain genome was found to significantly increase the host cell tolerance to acetic acid. The in silico analysis of these inserts was facilitated by the recently available genome sequence of this strain. In total, 65 complete or truncated ORFs were identified as putative determinants of acetic acid tolerance and an S. cerevisiae gene homologous to most of them was found. These include genes involved in cellular transport and transport routes, protein fate, protein synthesis, amino acid metabolism and transcription. The role of strong candidates in Z. bailii and S. cerevisiae acetic acid tolerance was confirmed based on homologous and heterologous expression analyses. ISA1307 genes homologous to S. cerevisiae genes GYP8, WSC4, PMT1, KTR7, RKR1, TIF3, ILV3 and MSN4 are proposed as strong candidate determinants of acetic acid tolerance. The ORF ZBAI_02295 that contains a functional domain associated to the uncharacterised integral membrane proteins of unknown function of the DUP family is also suggested as a relevant tolerance determinant

  19. Reaction mechanism in high Nb containing TiAl alloy by elemental powder metallurgy

    Institute of Scientific and Technical Information of China (English)

    WANG Yan-hang; LIN Jun-pin; HE Yue-hui; WANG Yan-li; LIN Zhi; CHEN Guo-liang

    2006-01-01

    High Nb containing TiAl alloy was fabricated in argon atmosphere by reactive hot pressing process. Reaction mechanism was investigated by means of microstructural analyses and thermodynamic calculations. The results show that it is feasible to prepare high Nb containing TiAl alloy with fine lamellar colonies by reactive hot pressing process. The reaction between Ti and Al powders is dominant in Ti-Al-Nb system. Nb powders dissolve into the Ti-Al matrix by diffusion. Pore nests are formed in situ after Nb powders diffusion. The hot pressing atmosphere is optimized by thermodynamic calculations. Vacuum or argon protective atmosphere should be adopted.

  20. Thermoanaerobacterium thermosaccharolyticum β-glucosidase: a glucose-tolerant enzyme with high specific activity for cellobiose

    Directory of Open Access Journals (Sweden)

    Pei Jianjun

    2012-07-01

    Full Text Available Abstract Background β-Glucosidase is an important component of the cellulase enzyme system. It does not only participate in cellulose degradation, it also plays an important role in hydrolyzing cellulose to fermentable glucose by relieving the inhibition of exoglucanase and endoglucanase from cellobiose. Therefore, the glucose-tolerant β-glucosidase with high specific activity for cellobiose might be a potent candidate for industrial applications. Results The β-glucosidase gene bgl that encodes a 443-amino-acid protein was cloned and over-expressed from Thermoanaerobacterium thermosaccharolyticum DSM 571 in Escherichia coli. The phylogenetic trees of β-glucosidases were constructed using Neighbor-Joining (NJ and Maximum-Parsimony (MP methods. The phylogeny and amino acid analysis indicated that the BGL was a novel β-glucosidase. By replacing the rare codons for the N-terminal amino acids of the target protein, the expression level of bgl was increased from 6.6 to 11.2 U/mg in LB medium. Recombinant BGL was purified by heat treatment followed by Ni-NTA affinity. The optimal activity was at pH 6.4 and 70°C. The purified enzyme was stable over pH range of 5.2–7.6 and had a 1 h half life at 68°C. The activity of BGL was significantly enhanced by Fe2+ and Mn2+. The Vmax of 64 U/mg and 120 U/mg were found for p-nitrophenyl-β-D-glucopyranoside (Km value of 0.62 mM and cellobiose (Km value of 7.9 mM, respectively. It displayed high tolerance to glucose and cellobiose. The Kcat for cellobiose was 67.7 s-1 at 60°C and pH 6.4, when the concentration of cellobiose was 290 mM. It was activated by glucose at concentrations lower that 200 mM. With glucose further increasing, the enzyme activity of BGL was gradually inhibited, but remained 50% of the original value in even as high as 600 mM glucose. Conclusions The article provides a useful novel β-glucosidase which displayed favorable properties: high glucose and cellobiose tolerance

  1. Heart Rate Variability during Simulated Hemorrhage with Lower Body Negative Pressure in High and Low Tolerant Subjects

    Science.gov (United States)

    2011-11-01

    body negative pressure in high and low tolerant subjects Carmen Hinojosa-Laborde1*, Caroline A. Rickards2, Kathy L. Ryan1 andVictor A. Convertino1 1 US...University School of Medicine, USA *Correspondence: Carmen Hinojosa-Laborde, U.S. Army Institute of Surgical Research, 3698 Chambers Pass, Fort Sam...Goldwater, D. J., Mont - gomery, L. D., and Convertino, V. A. (1986). Cardiovascular dynamics associated with tolerance to lower body negative pressure

  2. Tribological properties of high velocity arc sprayed Fe-Al based composite coatings at elevated temperature

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wei; ZHANG Shu; XU Wei-pu; ZU Zi-xin; XU Bin-shi

    2004-01-01

    Fe-Al based intermetallic composite coatings were in-situ synthesized using Fe-Al/Cr3C2 or Fe-Al/WC cored wires and high velocity are spraying (HVAS) technology. The tribological properties of the Fe-Al based intermetallic composite coatings were investigated using a ball-on-disc tribotester from room temperature to 650 ℃. The results show that the coatings have relatively high bond strength and micro-hardness. The tribological properties of Fe-Al/Cr3C2 and Fe-Al/WC composite coatings were further analyzed and compared. Low and stable wear rates of the Fe-Al based intermetallic composite coatings were indicated from room temperature to 650 ℃. The excellent wear resistance of the composite coatings in high temperature was discussed.

  3. High orientation Al films growth on LiNbO3 single crystal and its adhesion

    Institute of Scientific and Technical Information of China (English)

    LI Dong-mei; CHEN Jing-jing; PAN Feng

    2004-01-01

    High orientation Al films were deposited on 64°Y-XLiNbO3 substrate by DC magnetron sputtering and the influence of deposition temperature on microstructure and adhesion properties of Al films were investigated. The results show that crystallographic orientation of films varies with substrate temperature and the adhesion strength between LiNbO3 and Al films strongly depends on crystallographic orientation of Al films. The (111) orientated Al films shows stronger adhesion strength to LiNbO3 substrate than (100) orientated films. There is an optimum substrate temperature of 60 ℃ and hardening temperature of 200 ℃ for obtaining high (111) orientated Al films with good surface structure and adhesion property. Using this Al film, we have successfully fabricated the SAW filters with high frequency of about 1.89 GHz.

  4. AlGaN/GaN high electron mobility transistor with Al2O3+BCB passivation

    Institute of Scientific and Technical Information of China (English)

    张昇; 马晓华; 孙兵; 刘新宇; 魏珂; 余乐; 刘果果; 黄森; 王鑫华; 庞磊; 郑英奎; 李艳奎

    2015-01-01

    In this paper, A12O3 ultrathin film used as the surface passivation layer for AlGaN/GaN high electron mobility transistor (HEMT) is deposited by thermal atomic layer deposition (ALD), thereby avoiding plasma-induced damage and erosion to the surface. A comparison is made between the surface passivation in this paper and the conventional plasma enhanced chemical vapor deposition (PECVD) SiN passivation. A remarkable reduction of the gate leakage current and a significant increase in small signal radio frequency (RF) performance are achieved after applying Al2O3+BCB passivation. For the Al2O3+BCB passivated device with a 0.7 µm gate, the value of fmax reaches up to 100 GHz, but it decreases to 40 GHz for SiN HEMT. The fmax/ft ratio (≥4) is also improved after Al2O3+BCB passivation. The capacitance–voltage (C–V ) measurement demonstrates that Al2O3+BCB HEMT shows quite less density of trap states (on the order of magnitude of 1010 cm−2) than that obtained at commonly studied SiN HEMT.

  5. Multi-Core Technology for and Fault Tolerant High-Performance Spacecraft Computer Systems

    Science.gov (United States)

    Behr, Peter M.; Haulsen, Ivo; Van Kampenhout, J. Reinier; Pletner, Samuel

    2012-08-01

    The current architectural trends in the field of multi-core processors can provide an enormous increase in processing power by exploiting the parallelism available in many applications. In particular because of their high energy efficiency, it is obvious that multi-core processor-based systems will also be used in future space missions. In this paper we present the system architecture of a powerful optical sensor system based on the eight core multi-core processor P4080 from Freescale. The fault tolerant structure and the highly effective FDIR concepts implemented on different hardware and software levels of the system are described in detail. The space application scenario and thus the main requirements for the sensor system have been defined by a complex tracking sensor application for autonomous landing or docking manoeuvres.

  6. High cell density propionic acid fermentation with an acid tolerant strain of Propionibacterium acidipropionici.

    Science.gov (United States)

    Wang, Zhongqiang; Jin, Ying; Yang, Shang-Tian

    2015-03-01

    Propionic acid is an important chemical with wide applications and its production via fermentation is of great interest. However, economic production of bio-based propionic acid requires high product titer, yield, and productivity in the fermentation. A highly efficient and stable high cell density (HCD) fermentation process with cell recycle by centrifugation was developed for propionic acid production from glucose using an acid-tolerant strain of Propionibacterium acidipropionici, which had a higher specific growth rate, productivity, and acid tolerance compared to the wild type ATCC 4875. The sequential batch HCD fermentation at pH 6.5 produced propionic acid at a high titer of ∼40 g/L and productivity of 2.98 g/L h, with a yield of ∼0.44 g/g. The product yield increased to 0.53-0.62 g/g at a lower pH of 5.0-5.5, which, however, decreased the productivity to 1.28 g/L h. A higher final propionic acid titer of >55 g/L with a productivity of 2.23 g/L h was obtained in fed-batch HCD fermentation at pH 6.5. A 3-stage simulated fed-batch process in serum bottles produced 49.2 g/L propionic acid with a yield of 0.53 g/g and productivity of 0.66 g/L h. These productivities, yields and propionic acid titers were among the highest ever obtained in free-cell propionic acid fermentation.

  7. Efficacy and tolerability of high-dose phenobarbital in children with focal seizures.

    Science.gov (United States)

    Okumura, Akihisa; Nakahara, Eri; Ikeno, Mitsuru; Abe, Shinpei; Igarashi, Ayuko; Nakazawa, Mika; Takasu, Michihiko; Shimizu, Toshiaki

    2016-04-01

    We retrospectively reviewed the outcomes of children with focal epilepsy treated with oral high-dose phenobarbital. We reviewed data on children (agedphenobarbital (>5 mg/kg/day to maintain a target serum level >40 μg/mL) for at least 6 months. Seizure frequency was evaluated after phenobarbital titration, and 1 and 2 years after high-dose phenobarbital treatment commenced. Treatment was judged effective when seizure frequencies fell by ⩾75%. Seven boys and eight girls were treated. The median age at commencement of high-dose phenobarbital therapy was 30 months. The maximal serum phenobarbital level ranged from 36.5 to 62.9 μg/mL. High-dose PB was effective in seven. In two patients, treatment was transiently effective, but seizure frequency later returned to the baseline. High-dose PB was ineffective in six. No significant association between effectiveness and any clinical variable was evident. Drowsiness was recorded in nine patients, but no patient developed a behavioral problem or hypersensitivity. Oral high-dose phenobarbital was effective in 7 of 15 patients with focal epilepsy and well tolerated. High-dose PB may be useful when surgical treatment is difficult. Copyright © 2015 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  8. Field Testing of Tomato Chilling Tolerance under Varying Light and Temperature Conditions Caracterización de la Tolerancia al Frío en Tomate Dependiente de las Condiciones de Luz y Temperatura

    Directory of Open Access Journals (Sweden)

    Rafael Elizondo

    2010-12-01

    Full Text Available Chilling tolerance is a desirable trait in commercial tomato varieties, in order to extend the growing season and geographic range. Two Nearly Isogenic Lines (NILs with introgressions in chromosome 2 and 3 of Solanum habrochaites S. Knapp & D.M. Spooner, a cold-resistant wild tomato, were evaluated in the field. Four plantings were established between 21 August and 2 October 2006 (day 232 and 274. Throughout the experiment the heat sum was interpreted using air temperature to calculate growing degree days (base 12 °C and chilling hours (below 12 °C, with the daily light integral calculated as global solar radiation. The relative post-transplant growth rate, fruit set and yield, were evaluated over two successive 10-d periods. Chilling tolerance is expressed under high radiation and low temperature conditions, which occurred during the 10-d post-transplant evaluation period beginning on day 257, when both NILs achieved a leaf area growth rate 1.7 times higher than the control plants. During the second evaluation period, 10-20 d post-transplant, both NILs grew on average, 1.4 times more than the control. There were no significant differences in earliness or fruit set. These NILs should not be used as a direct source to obtain chilling tolerant varieties, because of the low fruit set, 84% lower in LA3921 than the control, probably due to linkage drag and poor environmental adaptability in both lines.La resistencia al frío es una característica deseable en cultivares de tomate, entre otras razones para ampliar el período de cultivo y la distribución geográfica. Se evaluaron dos líneas casi isogénicas de tomate, LA3921 y LA 3925 con introgresiones de Solanum habrochaites S. Knapp & D.M. Spooner (especie resistente al frío. Las introgresiones se ubican en los cromosomas 2 y 3. Se establecieron cuatro fechas al aire libre, entre el día juliano 232 y 274 (21 de agosto al 2 de octubre. Se analizó el clima en los períodos evaluados

  9. Efficacy and tolerability of high oral doses of levetiracetam in children with epilepsy.

    Science.gov (United States)

    Obeid, Makram; Pong, Amanda W

    2010-09-01

    Despite the advent of new antiepileptic drugs, many children continue to have refractory seizures. We sought to determine whether oral LEV is helpful in seizure control and tolerable at doses higher than 60mg/kg/day in the pediatric outpatient population. A retrospective chart review over a 1.5-year period was performed at the Columbia Comprehensive Epilepsy Center to identify children who were treated with levetiracetam doses titrated above the usual 40-60mg/kg/day. Data was collected on seizure semiology, epilepsy type, seizure frequency, concomitant antiepileptic drugs, and adverse effects. Thirty-two children, ranging in age from 1 to 19 years, required high dose levetiracetam. The median dosage of levetiracetam was 146mg/kg/day (range, 70-275mg/kg/day), and the median maximum serum trough level was 43mcg/ml (range, 20-121mcg/ml). All but one patient were taking one or more other antiepileptic drugs. A more than 50% reduction in seizure frequency was observed in 14 children (44%), with 5 achieving seizure freedom (16%). No response to high dose levetiracetam was found in 14 children (44%), and worsening of seizure frequency occurred in 4 (12%). Adverse effects were observed in 4 patients (12%), and were behavioral. Not only do some children tolerate high doses and serum levels of levetiracetam, but they may also benefit from them, suggesting that doses higher than 60mg/kg/day may be considered in children who partially respond to the lower doses. Copyright 2010 Elsevier B.V. All rights reserved.

  10. A novel 5-enolpyruvylshikimate-3-phosphate synthase shows high glyphosate tolerance in Escherichia coli and tobacco plants.

    Directory of Open Access Journals (Sweden)

    Gaoyi Cao

    Full Text Available A key enzyme in the shikimate pathway, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS is the primary target of the broad-spectrum herbicide glyphosate. Identification of new aroA genes coding for EPSPS with a high level of glyphosate tolerance is essential for the development of glyphosate-tolerant crops. In the present study, the glyphosate tolerance of five bacterial aroA genes was evaluated in the E. coli aroA-defective strain ER2799 and in transgenic tobacco plants. All five aroA genes could complement the aroA-defective strain ER2799, and AM79 aroA showed the highest glyphosate tolerance. Although glyphosate treatment inhibited the growth of both WT and transgenic tobacco plants, transgenic plants expressing AM79 aroA tolerated higher concentration of glyphosate and had a higher fresh weight and survival rate than plants expressing other aroA genes. When treated with high concentration of glyphosate, lower shikimate content was detected in the leaves of transgenic plants expressing AM79 aroA than transgenic plants expressing other aroA genes. These results suggest that AM79 aroA could be a good candidate for the development of transgenic glyphosate-tolerant crops.

  11. CaAl 12Si 4O 27, a New High-Pressure Phase Containing Al 6O 19 Clusters

    Science.gov (United States)

    Grey, I. E.; Madsen, I. C.; Hibberson, W. O.; O'Neill, H. St. C.

    2000-09-01

    CaAl12Si4O27, a new high-pressure phase in the CaO-Al2O3-SiO2 system, was prepared at 1550°C and 14 GPa. It has trigonal symmetry, P-3, with a=7.223(1) and c=8.614(3) Å. Its structure was solved using crystal chemistry principles and refined using the Rietveld method applied to powder X-ray diffraction data, Rwp=6.1%, RB=2.7%. The structure is a new type based on a close-packed anion lattice with a mixed layer stacking sequence ABACA≡(hc)2 and with Ca atoms ordered in one-seventh of the anion sites in alternate c-stacked layers. The Si atoms are ordered in both octahedral and tetrahedral sites while the Al atoms are ordered in two independent octahedral sites. Octahedral edge-shared clusters, Al6O19, occur in the structure, interconnected within the close-packed layers by corner-linking to SiO4 tetrahedra. The clusters are also connected by corner-sharing to nine-member rings of edge-shared Al- and Si-centered octahedra in adjacent layers. The new phase has structural features in common with the barium titanium ferrite of similar composition, BaFe11Ti3O23, as well as with the mineral simpsonite, Al4Ta3O13(OH), and alkali metal niobates which contain Nb6O19 clusters.

  12. High-quality AlN films grown on chemical vapor-deposited graphene films

    Directory of Open Access Journals (Sweden)

    Chen Bin-Hao

    2016-01-01

    Full Text Available We report the growth of high-quality AlN films on graphene. The graphene films were synthesized by CVD and then transferred onto silicon substrates. Epitaxial aluminum nitride films were deposited by DC magnetron sputtering on both graphene as an intermediate layer and silicon as a substrate. The structural characteristics of the AlN films and graphene were investigated. Highly c-axis-oriented AlN crystal structures are investigated based on the XRDpatterns observations.

  13. Effects of high magnetic field on modification of Al-Si alloy

    Institute of Scientific and Technical Information of China (English)

    LIAN Feng; QI Feng; LI Ting-ju; HU Guo-bing

    2005-01-01

    Effects of high magnetic field on modification of Al-6 %Si hypoeutectic alloy, Ak-12.6%Si eutectic alloy and Al-18 % Si hypereutectic alloy were studied. For the Al-6 % Si alloy, it is found that the sample modified by Na salt does not lose efficacy after remelting under high magnetic field. For the Al-12.6%Si alloy, if the sample modi fied by Na-salt is kept at the temperature of modification reaction, high magnetic field can postpone the effective time of the modification. For Al-18%Si alloy modified by P-salt, the primary Si in solidified structure concentrates at the edge of the sample and eutectic Si appears in the center of the sample under the condition without high magnetic field, while the primary Si distributes evenly in the sample when the high magnetic field is imposed. It is thought that the high magnetic field restrains the convection of the melt.

  14. X-ray and optical crystallographic parameters investigations of high frequency induction melted Al-(alpha-Al(2)O(3)) alloys.

    Science.gov (United States)

    Bourbia, A; Draissia, M; Bedboudi, H; Boulkhessaim, S; Debili, M Y

    2010-01-01

    This article deals with the microstructural strengthening mechanisms of aluminium by means of hard alpha-Al(2)O(3) alumina fine particles. A broad of understanding views covering materials preparations, elaboration process, characterization techniques and associated microstructural characteristic parameters measurements is given. In order to investigate the microstructural characteristic parameters and the mechanical strengthening mechanisms of pure aluminium by hard fine particles, a set of Al-(alpha-Al(2)O(3)) alloys samples were made under vacuum by high fusion temperature melting, the high frequency (HF) process, and rapidly solidified under ambient temperature from a mixture of cold-compacted high-pure fine Al and alpha-Al(2)O(3) powders. The as-solidified Al-(alpha-Al(2)O(3)) alloys were characterized by means of X-ray diffraction (XRD) analyses, optical microscopy observations and Vickers microhardness tests in both brut and heat-treated states. It was found that the as-solidified HF Al-(alpha-Al(2)O(3)) alloys with compositions below 4 wt.% (alpha-Al(2)O(3)) are single-phase microstructures of the solid solution FCC Al phase and over two-phase microstructures of the solid solution FCC Al and the Rhombohedral alpha-Al(2)O(3) phases. The optical micrographs reveal the presence of a grain size refinement in these alloys. Vickers microhardness of the as-solidified Al-(alpha-Al(2)O(3)) is increased by means of pure fine alpha-Al(2)O(3) alumina particles. These combined effects of strengthening and grain size refinement observed in the as-solidified Al-(alpha-Al(2)O(3)) alloys are essentially due to a strengthening of Al by the alpha-Al(2)O(3) alumina particles insertion in the (HF) melted and rapidly solidified alloys.

  15. Adverse reactions and tolerability of high-dose sublingual allergen immunotherapy

    Directory of Open Access Journals (Sweden)

    Moral A

    2016-06-01

    Full Text Available Angel Moral,1 Victoria Moreno,2 Francisco Girón,3 David El-Qutob,4 José D Moure,5 Manuel Alcántara,6 Antonia Padial,7 Alberto G Oehling,8 Carmen Millán,9 Fernando de la Torre10 1Allergy Service, Hospital Virgen del Valle, Toledo, 2Allergy Service, Hospital Blanca Paloma, Huelva, 3Consulta Privada, Granada, 4Allergy Service, Clínica Atenea, Castellón, 5Pediatric Department, Complejo Hospitalario Universitario de Santiago, A Coruña, 6Allergy Service, Complejo Hospitalario de Jaén, Jaén, 7Allergy Service, Hospital Infanta Sofía, Madrid, 8Centro de Alergia y Asma Balear, Mallorca, 9Consulta Privada, Cádiz, 10ALK-Abelló, SA, Madrid, Spain Background: Sublingual allergen immunotherapy is an effective treatment against allergic respiratory disease. Many studies have shown the safety of this type of therapy, although the factors that might affect the tolerability of high-dose sublingual immunotherapy have not been well established. The aim of this study was to determine the factors that affect the tolerability of sublingual allergen immunotherapy.Patients and methods: A total of 183 subjects aged ≥5 years, diagnosed with allergic rhinitis with/without mild to moderate asthma due to sensitization to grass, olive pollen, or mites, were included in this open, retrospective, multicentric, noninterventional study. Sublingual immunotherapy was administered for at least 3 months.Results: The most frequent adverse reaction was oral pruritus (13.7% of the patients. Most of the reactions were local (84.7% and immediate (93.5% and occurred during the initiation phase (60.6%. All reactions were mild to moderate in severity. No serious adverse reactions were registered. When comparing factors with potential influence on the occurrence of adverse reactions, the results between the groups of subjects with and without adverse reactions showed no statistically significant differences in sex (P=0.6417, age (P=0.1801, years since the disease was first

  16. ROAD MAP FOR DEVELOPMENT OF CRYSTAL-TOLERANT HIGH LEVEL WASTE GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Peeler, D.; Herman, C.

    2014-05-15

    The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystaltolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map. The planned research described in this road map is motivated by the potential for substantial economic benefits (significant reductions in glass volumes) that will be realized if the current constraints (T1% for WTP and TL for DWPF) are approached in an appropriate and technically defensible manner for defense waste and current melter designs. The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal-tolerant high-level waste (HLW) glasses targeting high waste loadings while still meeting process related limits and melter lifetime expectancies. The modeling effort will be an iterative process, where model form and a broader range of conditions, e.g., glass

  17. ROAD MAP FOR DEVELOPMENT OF CRYSTAL-TOLERANT HIGH LEVEL WASTE GLASSES

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.; Peeler, D.; Herman, C.

    2014-05-15

    The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystaltolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map. The planned research described in this road map is motivated by the potential for substantial economic benefits (significant reductions in glass volumes) that will be realized if the current constraints (T1% for WTP and TL for DWPF) are approached in an appropriate and technically defensible manner for defense waste and current melter designs. The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal-tolerant high-level waste (HLW) glasses targeting high waste loadings while still meeting process related limits and melter lifetime expectancies. The modeling effort will be an iterative process, where model form and a broader range of conditions, e.g., glass

  18. Fault Tolerance and COTS: Next Generation of High Performance Satellite Computers

    Science.gov (United States)

    Behr, P.; Bärwald, W.; Brieß, K.; Montenegro, S.

    The increasing complexity of future satellite missions requires adequately powerful on- board computer systems. The obvious performance gap between state-of-the-art micro- processor technology ("commercial-off-the-shelf", COTS) and available radiation hard components already impedes the realization of innovative satellite applications requiring high performance on-board data processing. In the paper we emphasize the advantages of the COTS approach for future OBCS and we show why we are convinced that this approach is feasible. We present the architecture of the fault tolerant control computer of the BIRD satellite and finally we show some results of the BIRD mission after 20 months in orbit, especially the experience with its COTS based control computer.

  19. Isolation and cultivation of microalgae select for low growth rate and tolerance to high pH

    DEFF Research Database (Denmark)

    Berge, Terje; Daugbjerg, Niels; Hansen, Per Juel

    2012-01-01

    Harmful microalgal blooms or red tides are often associated with high levels of pH. Similarly, species and strains of microalgae cultivated in the laboratory with enriched media experience recurrent events of high pH between dilutions with fresh medium. To study the potential for laboratory...... of upper pH tolerance limits were higher in the younger (20 years). These results suggest selection of strains best adapted to tolerate or postpone/avoid events of high pH in the laboratory. Our data have implications for experimental studies of pH response and reaction norms in general of microalgae...

  20. Adverse reactions and tolerability of high-dose sublingual allergen immunotherapy

    Science.gov (United States)

    Moral, Angel; Moreno, Victoria; Girón, Francisco; El-Qutob, David; Moure, José D; Alcántara, Manuel; Padial, Antonia; Oehling, Alberto G; Millán, Carmen; de la Torre, Fernando

    2016-01-01

    Background Sublingual allergen immunotherapy is an effective treatment against allergic respiratory disease. Many studies have shown the safety of this type of therapy, although the factors that might affect the tolerability of high-dose sublingual immunotherapy have not been well established. The aim of this study was to determine the factors that affect the tolerability of sublingual allergen immunotherapy. Patients and methods A total of 183 subjects aged ≥5 years, diagnosed with allergic rhinitis with/without mild to moderate asthma due to sensitization to grass, olive pollen, or mites, were included in this open, retrospective, multicentric, noninterventional study. Sublingual immunotherapy was administered for at least 3 months. Results The most frequent adverse reaction was oral pruritus (13.7% of the patients). Most of the reactions were local (84.7%) and immediate (93.5%) and occurred during the initiation phase (60.6%). All reactions were mild to moderate in severity. No serious adverse reactions were registered. When comparing factors with potential influence on the occurrence of adverse reactions, the results between the groups of subjects with and without adverse reactions showed no statistically significant differences in sex (P=0.6417), age (P=0.1801), years since the disease was first diagnosed (P=0.3800), treatment composition (P=0.6946), polysensitization (P=0.1730), or clinical diagnosis (P=0.3354). However, it was found that treatment duration had a statistically significant influence (3 months, >3 months: P=0.0442) and the presence of asthma was close to statistical significance (P=0.0847). Conclusion In our study, treatment duration is significantly associated with the occurrence of adverse reactions after the administration of high doses of sublingual allergen immunotherapy. PMID:27418842

  1. High-throughput phenotyping to detect drought tolerance QTL in wild barley introgression lines.

    Directory of Open Access Journals (Sweden)

    Nora Honsdorf

    Full Text Available Drought is one of the most severe stresses, endangering crop yields worldwide. In order to select drought tolerant genotypes, access to exotic germplasm and efficient phenotyping protocols are needed. In this study the high-throughput phenotyping platform "The Plant Accelerator", Adelaide, Australia, was used to screen a set of 47 juvenile (six week old wild barley introgression lines (S42ILs for drought stress responses. The kinetics of growth development was evaluated under early drought stress and well watered treatments. High correlation (r=0.98 between image based biomass estimates and actual biomass was demonstrated, and the suitability of the system to accurately and non-destructively estimate biomass was validated. Subsequently, quantitative trait loci (QTL were located, which contributed to the genetic control of growth under drought stress. In total, 44 QTL for eleven out of 14 investigated traits were mapped, which for example controlled growth rate and water use efficiency. The correspondence of those QTL with QTL previously identified in field trials is shown. For instance, six out of eight QTL controlling plant height were also found in previous field and glasshouse studies with the same introgression lines. This indicates that phenotyping juvenile plants may assist in predicting adult plant performance. In addition, favorable wild barley alleles for growth and biomass parameters were detected, for instance, a QTL that increased biomass by approximately 36%. In particular, introgression line S42IL-121 revealed improved growth under drought stress compared to the control Scarlett. The introgression line showed a similar behavior in previous field experiments, indicating that S42IL-121 may be an attractive donor for breeding of drought tolerant barley cultivars.

  2. Improved glucose tolerance after high-load strength training in patients undergoing dialysis

    DEFF Research Database (Denmark)

    Mølsted, Stig; Harrison, Adrian Paul; Eidemak, Inge

    2013-01-01

    glucose tolerance (n = 9). Conclusion: The conducted strength training was associated with a significant improvement in glucose tolerance in patients with impaired glucose tolerance or type 2 diabetes undergoing dialysis. The effect was apparently not associated with muscle hypertrophy, whereas the muscle...... a week. Muscle fiber size, composition and capillary density were analyzed in biopsies obtained in the vastus lateralis muscle. Glucose tolerance and the insulin response were measured by a 2-hour oral glucose tolerance test. Results: All outcome measures remained unchanged during the control period....... After strength training the relative area of type 2X fibers was decreased. Muscle fiber size and capillary density remained unchanged. After the strength training, insulin concentrations were significantly lower in patients with impaired glucose tolerance or type 2 diabetes (n = 14) (fasting insulin...

  3. High Strain, Strain Rate Behavior of PTFE/Al/W

    Science.gov (United States)

    Addiss, John; Cai, Jing; Walley, Steve; Proud, William; Nesterenko, Vitali

    2007-06-01

    Conventional dropweight technique was modified to accommodate low amplitude signals from low strength, cold isostatically pressed energetic ``heavy'' composites of polytetrafluoroethylene (PTFE)/AL/W. The fracture strength, strain and post-critical behaviour of fractured samples were measured for samples of different porosity and W grain size (the masses of each component being the same in each case). Unusual phenomenon of significantly higher strength (55 MPa) of porous composites (density 5.9 g/cc) with small tungsten particles (1 micron) in comparison with strength (32 MPa) of dense composites (7.1 g/cc) with larger tungsten particles (20 micron) was observed. This is attributed to force chains created by a network of small tungsten particles. Interrupted tests at the different level of strains revealed mechanism of fracture under dynamic compression.

  4. Liver Transplant Tolerance and Its Application to the Clinic: Can We Exploit the High Dose Effect?

    OpenAIRE

    Cunningham, Eithne C.; Sharland, Alexandra F.; G. Alex Bishop

    2013-01-01

    The tolerogenic properties of the liver have long been recognised, especially in regard to transplantation. Spontaneous acceptance of liver grafts occurs in a number of experimental models and also in a proportion of clinical transplant recipients. Liver graft acceptance results from donor antigen-specific tolerance, demonstrated by the extension of tolerance to other grafts of donor origin. A number of factors have been proposed to be involved in liver transplant tolerance induction, includi...

  5. Plant tolerance to high temperature in a changing environment: scientific fundamentals and production of heat stress-tolerant crops

    OpenAIRE

    Craita eBita; Tom eGerats

    2013-01-01

    Global warming is predicted to have a general negative effect on plant growth due to the damaging effect of high temperatures on plant development. The increasing threat of climatological extremes including very high temperatures might lead to catastrophic loss of crop productivity and result in wide spread famine. In this review, we assess the impact of global climate change on the agricultural crop production. There is a differential effect of climate change both in terms of geographic loca...

  6. 27 Al MAS NMR Studies of HBEA Zeolite at Low to High Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Jian Zhi; Wan, Chuan; Vjunov, Aleksei; Wang, Meng; Zhao, Zhenchao; Hu, Mary Y.; Camaioni, Donald M.; Lercher, Johannes A.

    2017-06-01

    27Al single pulse (SP) MAS NMR spectra of HBEA zeolites with high Si/Al ratios of 71 and 75 were obtained at three magnetic field strengths of 7.05, 11.75 and 19.97 T. High field 27Al MAS NMR spectra acquired at 19.97 T show significantly improved spectral resolution, resulting in at least two well-resolved tetrahedral-Al NMR peaks. Based on the results obtained from 27Al MAS and MQMAS NMR acquired at 19.97 T, four different quadrupole peaks are used to deconvolute the 27Al SP MAS spectra acquired at vari-ous fields by using the same set of quadrupole coupling constants, asymmetric parameters and relative integrated peak intensities for the tetrahedral Al peaks. The line shapes of individual peaks change from typical quadrupole line shape at low field to essentially symmetrical line shapes at high field. We demonstrate that for fully hydrated HBEA zeolites the effect of second order quadrupole interaction can be ignored and quantitative spectral analysis can be performed by directly fitting the high field spectra using mixed Gaussian/Lorentzian line shapes. Also, the analytical steps described in our work allow direct assignment of spectral intensity to individual Al tetrahedral sites (T-sites) of zeolite HBEA. Finally, the proposed concept is suggested generally applicable to other zeo-lite framework types, thus, allowing a direct probing of Al distributions by NMR spectroscopic methods in zeolites with high confi-dence.

  7. High Permeability Ternary Palladium Alloy Membranes with Improved Sulfur and Halide Tolerances

    Energy Technology Data Exchange (ETDEWEB)

    K. Coulter

    2010-12-31

    The project team consisting of Southwest Research Institute{reg_sign} (SwRI{reg_sign}), Georgia Institute of Technology (GT), the Colorado School of Mines (CSM), TDA Research, and IdaTech LLC was focused on developing a robust, poison-tolerant, hydrogen selective free standing membrane to produce clean hydrogen. The project completed on schedule and on budget with SwRI, GT, CSM, TDA and IdaTech all operating independently and concurrently. GT has developed a robust platform for performing extensive DFT calculations for H in bulk palladium (Pd), binary alloys, and ternary alloys of Pd. Binary alloys investigated included Pd96M4 where M = Li, Na, Mg, Al, Si, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Tc, Ru, Rh, Ag, Cd, In, Sn, Sb, Te, Hf, Ta, W, Re, Os, Ir, Pt, Au, Tl, Pb, Bi, Ce, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. They have also performed a series of calculations on Pd{sub 70}Cu{sub 26}Ag{sub 4}, Pd{sub 70}Cu{sub 26}Au{sub 4}, Pd{sub 70}Cu{sub 26}Ni{sub 4}, Pd{sub 70}Cu{sub 26}Pt{sub 4}, and Pd{sub 70}Cu{sub 26}Y{sub 4}. SwRI deposited and released over 160 foils of binary and ternary Pd alloys. There was considerable work on characterizing and improving the durability of the deposited foils using new alloy compositions, post annealing and ion bombardment. The 10 and 25 {micro}m thick films were sent to CSM, TDA and IdaTech for characterization and permeation testing. CSM conducted over 60 pure gas permeation tests with SwRI binary and ternary alloy membranes. To date the PdAu and PdAuPt membranes have exhibited the best performance at temperatures in the range of 423-773 C and their performance correlates well with the predictions from GT. TDA completed testing under the Department of Energy (DOE) WGS conditions on over 16 membranes. Of particular interest are the PdAuPt alloys that exhibited only a 20% drop in flux when sulfur was added to the gas mixture and the flux was completely recovered when the sulfur flow was stopped. IdaTech tested binary

  8. High speed fault tolerant secure communication for muon chamber using FPGA based GBTx emulator

    Science.gov (United States)

    Sau, Suman; Mandal, Swagata; Saini, Jogender; Chakrabarti, Amlan; Chattopadhyay, Subhasis

    2015-12-01

    The Compressed Baryonic Matter (CBM) experiment is a part of the Facility for Antiproton and Ion Research (FAIR) in Darmstadt at the GSI. The CBM experiment will investigate the highly compressed nuclear matter using nucleus-nucleus collisions. This experiment will examine lieavy-ion collisions in fixed target geometry and will be able to measure hadrons, electrons and muons. CBM requires precise time synchronization, compact hardware, radiation tolerance, self-triggered front-end electronics, efficient data aggregation schemes and capability to handle high data rate (up to several TB/s). As a part of the implementation of read out chain of Muon Cliamber(MUCH) [1] in India, we have tried to implement FPGA based emulator of GBTx in India. GBTx is a radiation tolerant ASIC that can be used to implement multipurpose high speed bidirectional optical links for high-energy physics (HEP) experiments and is developed by CERN. GBTx will be used in highly irradiated area and more prone to be affected by multi bit error. To mitigate this effect instead of single bit error correcting RS code we have used two bit error correcting (15, 7) BCH code. It will increase the redundancy which in turn increases the reliability of the coded data. So the coded data will be less prone to be affected by noise due to radiation. The data will go from detector to PC through multiple nodes through the communication channel. The computing resources are connected to a network which can be accessed by authorized person to prevent unauthorized data access which might happen by compromising the network security. Thus data encryption is essential. In order to make the data communication secure, advanced encryption standard [2] (AES - a symmetric key cryptography) and RSA [3], [4] (asymmetric key cryptography) are used after the channel coding. We have implemented GBTx emulator on two Xilinx Kintex-7 boards (KC705). One will act as transmitter and other will act as receiver and they are connected

  9. Towards Ultra-High Q Microresonators in High-Index Contrast AlGaAs-On-Insulator

    DEFF Research Database (Denmark)

    Pu, Minhao; Kamel, Ayman Nassar; Stassen, Erik

    2017-01-01

    We demonstrate an AlGaAs-on-insulator microresonator with intrinsic Q as high as 690,000. We optimized the fabrication and investigated the impact of waveguide dimension on the Q in such a high-index contrast platform.......We demonstrate an AlGaAs-on-insulator microresonator with intrinsic Q as high as 690,000. We optimized the fabrication and investigated the impact of waveguide dimension on the Q in such a high-index contrast platform....

  10. High Spectrum Narrowing Tolerant 112 Gb/s Dual Polarization QPSK Optical Communication Systems Using Digital Adaptive Channel Estimation

    DEFF Research Database (Denmark)

    Zhang, Xu; Pang, Xiaodan; Dogadaev, Anton Konstantinovich

    2012-01-01

    We experimentally demonstrate high spectrum narrowing tolerant 112-Gb/s QPSK polarization multiplex system based on digital adaptive channel estimation method. The proposed algorithm is able to detect severe spectrum-narrowed signal even with 20GHz 3dB bandwidth.......We experimentally demonstrate high spectrum narrowing tolerant 112-Gb/s QPSK polarization multiplex system based on digital adaptive channel estimation method. The proposed algorithm is able to detect severe spectrum-narrowed signal even with 20GHz 3dB bandwidth....

  11. Deposition of highly textured AlN thin films by reactive high power impulse magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Milena A. [Department of Solid State Electronics, Ångström Laboratory, Uppsala University, Box 534, SE-752 21 Uppsala, Sweden and School of Electrical and Computer Engineering, University of Campinas, CEP 13.083-852 Campinas-SP (Brazil); Törndahl, Tobias; Katardjiev, Ilia; Kubart, Tomas, E-mail: tomas.kubart@angstrom.uu.se [Department of Solid State Electronics, Ångström Laboratory, Uppsala University, Box 534, SE-752 21 Uppsala (Sweden)

    2015-03-15

    Aluminum nitride thin films were deposited by reactive high power impulse magnetron sputtering (HiPIMS) and pulsed direct-current on Si (100) and textured Mo substrates, where the same deposition conditions were used for both techniques. The films were characterized by x-ray diffraction and atomic force microscopy. The results show a pronounced improvement in the AlN crystalline texture for all films deposited by HiPIMS on Si. Already at room temperature, the HiPIMS films exhibited a strong preferred (002) orientation and at 400 °C, no contributions from other orientations were detected. Despite the low film thickness of only 200 nm, an ω-scan full width at half maximum value of 5.1° was achieved on Si. The results are attributed to the high ionization of sputtered material achieved in HiPIMS. On textured Mo, there was no significant difference between the deposition techniques.

  12. Effect of trace rare earth element Er on high pure Al

    Institute of Scientific and Technical Information of China (English)

    杨军军; 聂祚仁; 金头男; 徐国富; 付静波; 阮海琼; 左铁镛

    2003-01-01

    The influence of trace Er addition on high pure aluminum was studied by mechanical properties measurement,hardness measurement, optical microscope,transmission electron microscope and energy spectrum analysis. The results show that minor Er in the studied alloy exists in the form of Al3Er,only a few of Er in α-Al based solid solution .Primary Al3Er particles formed during solidification were often found at the center of aluminum grains and acted as heterogeneous nucleus, also increased the rate of nucleation, therefore the grain are remarkably refined. Trace Er addition to high pure aluminum is able to increase the mechanical properties of high pure Al, which is caused by fine grain strengthening, substructure strengthening and precipitation strengthening. The recrystallization temperature of Er-doped aluminum increases above 50 ℃, which is caused by the pinning effect of highly dispersed fine Al3Er precipitates on dislocations and sub-grain boundaries.

  13. Comparison of ALD and IBS Al2O3 films for high power lasers

    Science.gov (United States)

    Liu, Hao; Jensen, Lars; Becker, Jürgen; Wurz, Marc Christopher; Ma, Ping; Ristau, Detlev

    2016-12-01

    Atomic layer deposition (ALD) has been widely studied in Micro-electronics due to its self-terminating property. ALD also grows film coatings with precise thickness and nodular-free structure, which are desirable properties for high power coatings. The depositing process was studied to produce uniform, stable and economic Al2O3 single layers. The layer properties relevant to high power laser industry were studied and compared with IBS Al2O3 single layers. ALD Al2O3 showed a stable growth of 0.104 nm/cycle, band gap energy of 6.5 eV and tensile stress of about 480 MPa. It also showed a low absorption at wavelength 1064 nm within several ppm, and LIDT above 30 J/cm2. These properties are superior to the reference IBS Al2O3 single layers and indicate a high versatility of ALD Al2O3 for high power coatings.

  14. Development and High Temperature Property Evaluation of Ni-Co-Cr-Al Composite Electroforms

    Science.gov (United States)

    Srivastava, Meenu; Siju; Balaraju, J. N.; Ravisankar, B.

    2015-05-01

    Ni-Co-Cr-Al composite electroforms were developed with cobalt content of 10 and 40 wt.%. Cr and Al nano-particles were suspended in sulphamate electrolyte and co-deposited in the Ni-Co matrices. The surface morphology was investigated using field emission scanning electron microscope and the composition analyzed by energy-dispersive x-ray analysis. The oxidation resistance of the electroforms was studied from 600 to 1000 °C. The weight gain of Ni-10 wt.%Co-Cr-Al was less (better oxidation resistance) compared to Ni-Cr-Al and Ni-40 wt.%Co-Cr-Al. The x-ray diffraction studies revealed that the oxidation product formed on the surface of Ni-Cr-Al and Ni-10 wt.%Co-Cr-Al consisted of NiO and Al2O3, while Ni-40 wt.%Co-Cr-Al comprised oxides such as NiCo2O4, CrO3, CoO, NiO, and Al2O3. The hot corrosion behavior was investigated in 75%Na2SO4 + 25%NaCl environment at 800 °C. It was found that the hot corrosion resistance of the composite coating improved with increase in cobalt content. The probable composition suitable for high-temperature applications was found to be Ni-10 wt.%Co-Cr-Al.

  15. High-resolution /sup 27/Al NMR study of calcium aluminate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yakerson, V.I.; Nissenbaum, V.D.; Golosman, E.Z.; Mastikhin, V.M.

    1987-06-01

    The high-resolution /sup 27/Al NMR spectra of calcium aluminates, calcium hydroaluminates, and calcium alumina supports and catalysts have been studied. The structures of the anhydrous calcium aluminates (CaAl/sub 2/O/sub 3/, CaAl/sub 4/O/sub 7/, 3CaO x Al/sub 2/O/sub 3/, 12CaO x 7Al/sub 2/O/sub 3/, talyum) consist of aluminum-oxygen tetrahedra and contain various types of aluminum atoms, the nonequivalence of which increases in going from strongly basic to weakly basic aluminates. In the NMR spectrum the signal of octahedrally coordinated aluminum is due to disordered aluminum-oxygen structures. During the forming of the calcium-alumina catalysts and supports the process (AlO/sub 4/) ..-->.. (AlO/sub 6/) takes place during hydration, and (AlO/sub 6/) ..-->.. (AlO/sub 4/) during thermolysis; the nonequivalence of the tetrahedrally coordinated aluminum atoms decreases, while the (AlO/sub 4/):(AlO/sub 6/) ratio decreases as the degree of hydration increases.

  16. A gyroscope fabrication method for high sensitivity and robustness to fabrication tolerances

    Science.gov (United States)

    Sung, Jungwoo; Kim, Jin Young; Seok, Seyeong; Kwon, Hyuckjin J.; Kim, Minseo; Kim, Geonhwee; Lim, Geunbae

    2014-07-01

    MEMS gyroscopes have favorable characteristics, including small size, high throughput, and low cost. The performance of MEMS gyroscopes depends on the displacement sensitivity of the capacitors. In this paper, we describe the fabrication of 300-µm-thick gyroscopes that can provide high displacement sensitivity and are robust to fabrication tolerances, i.e. deep reactive ion etch (DRIE) rate uniformity. When thick structures are perforated using DRIE to achieve high-aspect-ratio features, footing is commonly observed. However, we describe a fabrication method that circumvents problems associated with footing and side-wall etching, so that the gyroscopes can have uniform dimensions and small variations across the wafer. Using a post-fabrication translation approach, the position of capacitors is modified following DRIE, and the gap in the gyroscopes can be reduced to 3 μm, which leads to an aspect ratio of 100. Using this method, we fabricated MEMS gyroscopes that can overcome the DRIE aspect ratio limit and have capacitors with higher sensitivities than those of other gyroscopes, which typically employ substrates that are less than 100 µm thick. The gyroscope had a resonant frequency of 9.91 kHz, a quality factor of 2500 and a sensitivity of 23 mV/[deg/s].

  17. Limits to the thermal tolerance of corals adapted to a highly fluctuating, naturally extreme temperature environment

    Science.gov (United States)

    Schoepf, Verena; Stat, Michael; Falter, James L.; McCulloch, Malcolm T.

    2015-12-01

    Naturally extreme temperature environments can provide important insights into the processes underlying coral thermal tolerance. We determined the bleaching resistance of Acropora aspera and Dipsastraea sp. from both intertidal and subtidal environments of the naturally extreme Kimberley region in northwest Australia. Here tides of up to 10 m can cause aerial exposure of corals and temperatures as high as 37 °C that fluctuate daily by up to 7 °C. Control corals were maintained at ambient nearshore temperatures which varied diurnally by 4-5 °C, while treatment corals were exposed to similar diurnal variations and heat stress corresponding to ~20 degree heating days. All corals hosted Symbiodinium clade C independent of treatment or origin. Detailed physiological measurements showed that these corals were nevertheless highly sensitive to daily average temperatures exceeding their maximum monthly mean of ~31 °C by 1 °C for only a few days. Generally, Acropora was much more susceptible to bleaching than Dipsastraea and experienced up to 75% mortality, whereas all Dipsastraea survived. Furthermore, subtidal corals, which originated from a more thermally stable environment compared to intertidal corals, were more susceptible to bleaching. This demonstrates that while highly fluctuating temperatures enhance coral resilience to thermal stress, they do not provide immunity to extreme heat stress events.

  18. Limits to the thermal tolerance of corals adapted to a highly fluctuating, naturally extreme temperature environment.

    Science.gov (United States)

    Schoepf, Verena; Stat, Michael; Falter, James L; McCulloch, Malcolm T

    2015-12-02

    Naturally extreme temperature environments can provide important insights into the processes underlying coral thermal tolerance. We determined the bleaching resistance of Acropora aspera and Dipsastraea sp. from both intertidal and subtidal environments of the naturally extreme Kimberley region in northwest Australia. Here tides of up to 10 m can cause aerial exposure of corals and temperatures as high as 37 °C that fluctuate daily by up to 7 °C. Control corals were maintained at ambient nearshore temperatures which varied diurnally by 4-5 °C, while treatment corals were exposed to similar diurnal variations and heat stress corresponding to ~20 degree heating days. All corals hosted Symbiodinium clade C independent of treatment or origin. Detailed physiological measurements showed that these corals were nevertheless highly sensitive to daily average temperatures exceeding their maximum monthly mean of ~31 °C by 1 °C for only a few days. Generally, Acropora was much more susceptible to bleaching than Dipsastraea and experienced up to 75% mortality, whereas all Dipsastraea survived. Furthermore, subtidal corals, which originated from a more thermally stable environment compared to intertidal corals, were more susceptible to bleaching. This demonstrates that while highly fluctuating temperatures enhance coral resilience to thermal stress, they do not provide immunity to extreme heat stress events.

  19. High tolerance of protozooplankton to ocean acidification in an Arctic coastal plankton community

    Directory of Open Access Journals (Sweden)

    N. Aberle

    2012-09-01

    Full Text Available Impacts of ocean acidification (OA on marine biota have been observed in a wide range of marine systems. We used a mesocosm approach to study the response of a high Arctic coastal protozooplankton (PZP in the following community during the post-bloom period in the Kongsfjorden (Svalbard to direct and indirect effects of high pCO2/low pH. We found almost no direct effects of OA on PZP composition and diversity. Both, the relative shares of ciliates and heterotrophic dinoflagellates as well as the taxonomic composition of protozoans remained unaffected by changes in pCO2/pH. The different pCO2 treatments did not have any effect on food availability and phytoplankton composition and thus no indirect effects e.g. on the total carrying capacity and phenology of PZP could be observed. Our data points at a high tolerance of this Arctic PZP community to changes in pCO2/pH. Future studies on the impact of OA on plankton communities should include PZP in order to test whether the observed low sensitivity of protozoans to OA is typical for coastal communities where changes in seawater pH occur frequently.

  20. Highly reliable high-power AlGaAs/GaAs 808 nm diode laser bars

    Science.gov (United States)

    Hülsewede, R.; Schulze, H.; Sebastian, J.; Schröder, D.; Meusel, J.; Hennig, P.

    2007-02-01

    There are strong demands at the market to increase power and reliability for 808 nm diode laser bars. Responding to this JENOPTIK Diode Lab GmbH developed high performance 808 nm diode laser bars in the AlGaAs/GaAs material system with special emphasis to high power operation and long term stability. Optimization of the epitaxy structure and improvements in the diode laser bar design results in very high slope efficiency of >1.2 W/A, low threshold current and small beam divergence in slow axis direction. Including low serial resistance the overall wall plug efficiency is up to 65% for our 20%, 30% and 50% filling factor 10 mm diode laser bars. With the JENOPTIK Diode Lab cleaving and coating technique the maximum output power is 205 W in CW operation and 377 W in QCW operation (200 μs, 2% duty cycle) for bars with 50% filling factor. These bars mounted on micro channel cooled package are showing a very high reliability of >15.000 h. Mounted on conductive cooled package high power operation at 100 W is demonstrated for more than 5000h.

  1. AlGaN-based deep-ultraviolet light-emitting diodes grown on high-quality AlN template using MOVPE

    KAUST Repository

    Yan, Jianchang

    2015-03-01

    In this article, we report the growth of high-quality AlN film using metal-organic vapor phase epitaxy. Three layers of middle-temperature (MT) AlN were introduced during the high-temperature (HT) AlN growth. During the MT-AlN layer growth, aluminum and nitrogen sources were closed for 6 seconds after every 5-nm MT-AlN, while H2 carrier gas was always on. The threading dislocation density in an AlN epi-layer on a sapphire substrate was reduced by almost half. AlGaN-based deep-ultraviolet light-emitting diodes were further fabricated based on the AlN/sapphire template. At 20 mA driving current, the emitted peak wavelength is 284.5 nm and the light output power exceeds 3 mW.

  2. Formation of Nanoscale Intermetallic Phases in Ni Surface Layer at High Intensity Implantation of Al Ions

    Institute of Scientific and Technical Information of China (English)

    I.A.Bozhko; S.V.Fortuna; I.A.Kurzina; I.B.Stepanov; E.V.Kozlov; Yu.P. Sharkeev

    2004-01-01

    The results of experimental study of nanoscale intermetallic formation in surface layer of a metal target at ion implantation are presented. To increase the thickness of the ion implanted surface layer the high intensive ion implantation is used. Compared with the ordinary ion implantation, the high intensive ion implantation allows a much thicker modified surface layer. Pure polycrystalline nickel was chosen as a target. Nickel samples were irradiated with Al ions on the vacuum-arc ion beam and plasma flow source "Raduga-5". It was shown that at the high intensity ion implantation the fine dispersed particles of Ni3Al, NiAl intermetallic compounds and solid solution Al in Ni are formed in the nickel surface layer of 200 nm and thicker. The formation of phases takes place in complete correspondence with the Ni-Al phase diagram.

  3. Hot Workability and Superplasticity of Low-Al and High-Nb Containing TiAl Alloys

    Science.gov (United States)

    Tang, Bin; Zhao, Fengtong; Chu, Yudong; Kou, Hongchao; Li, Jinshan

    2017-09-01

    The superplastic deformation mechanism of low-Al and high-Nb containing TiAl alloy was investigated in compression mode. The experimental results showed that intense dynamic recrystallization (DRX) breaks the balance and leads to a significant drop in flow stress after the peak when deforming below 950°C. Arrhenius kinetic analysis revealed that the activation energy for superplastic compression first increased then decreased with temperature, suggesting a change in the deformation mechanism. Microstructure observations showed that, when deformed at 850°C, the deformation mechanism was grain-boundary sliding accommodated by γ-DRX, γ-intragranular deformation, and β/B2-phase decomposition, while the mechanism was grain-boundary sliding accommodated by γ-DRX, β/B2-DRX, and γ → β/B2 + α 2 phase transformation when deformed at 1000°C. After compression, the microstructure tended to be uniform, which may yield important information for the development of new deformation techniques for TiAl alloys.

  4. Efficient nitrogen-fixing Rhizobium strains isolated from amazonian soils are highly tolerant to acidity and aluminium.

    Science.gov (United States)

    Avelar Ferreira, Paulo Ademar; Bomfeti, Cleide Aparecida; Lima Soares, Bruno; de Souza Moreira, Fatima Maria

    2012-05-01

    One of the most cultivated and consumed vegetables in Brazil is the common bean, Phaseolus vulgaris L. The symbiosis of this plant species with nitrogen-fixing bacteria that are adapted to the stresses commonly found in tropical soils can increase production. The aim of this study was to evaluate the symbiotic effectiveness of bacterial strains from soils under different land uses in the Amazon region. Further, rhizobia tolerance to acidity and aluminium and the involvement of some possible physiological mechanisms of such tolerance were also investigated. In assessing the efficiency of biological nitrogen fixation, inoculation with strains UFLA04-195, UFLA04-173 and UFLA04-202, belonging to the genus Rhizobium, resulted in greater plant growth, higher shoot nitrogen content and good nodulation compared to the inoculation with the strain CIAT 899 (R. tropici), and to the mineral nitrogen control or Burkholderia fungorum strains that nodulated or not bean plants. These efficient strains grew better at pH 5.0 than at pH 6.0 or pH 6.9; they also tolerated up to 1 mmol l(-1) of Al(3+) and showed an increased production of exopolysaccharides where the growing rates were less (pH 6.0 and pH 6.9). With respect to aluminium, the highest production of EPS produced greater tolerance to this element. Taken together, these results indicate that the strains evaluated in this study were tolerant to acidity and aluminium; they appeared to have developed resistance mechanisms such as EPS production and a resistant cell outer membrane (indicated by resistance to polymyxin and methyl violet). As these strains also gave increased yields of the host species, further studies on whether to recommend these strains as inoculants are already underway.

  5. Mechanisms for tolerance of very high tissue phosphorus concentrations in Ptilotus polystachyus.

    Science.gov (United States)

    Aziz, Tariq; Lambers, Hans; Nicol, Dion; Ryan, Megan H

    2015-04-01

    Study of plants with unusual phosphorus (P) physiology may assist development of more P-efficient crops. Ptilotus polystachyus grows well at high P supply, when shoot P concentrations ([P]) may exceed 40 mg P g(-1) dry matter (DM). We explored the P physiology of P. polystachyus seedlings grown in nutrient solution with 0-5 mM P. In addition, young leaves and roots of soil-grown plants were used for cryo-scanning electron microscopy and X-ray microanalysis. No P-toxicity symptoms were observed, even at 5 mM P in solution. Shoot DM was similar at 0.1 and 1.0 mM P in solution, but was ∼14% lower at 2 and 5 mM P. At 1 mM P, [P] was 36, 18, 14 and 11 mg P g(-1) DM in mature leaves, young leaves, stems and roots, respectively. Leaf potassium, calcium and magnesium concentrations increased with increasing P supply. Leaf epidermal and palisade mesophyll cells had similar [P]. The root epidermis and most cortical cells had senesced, even in young roots. We conclude that preferential accumulation of P in mature leaves, accumulation of balancing cations and uniform distribution of P across leaf cell types allow P. polystachyus to tolerate very high leaf [P].

  6. Metal dynamics and tolerance of Typha domingensis exposed to high concentrations of Cr, Ni and Zn.

    Science.gov (United States)

    Mufarrege, M M; Hadad, H R; Di Luca, G A; Maine, M A

    2014-07-01

    Typha domingensis was exposed to a 100mgL(-1) Cr+100mgL(-1) Ni+100mgL(-1) Zn solution. Metal tolerance and metal accumulation in plant tissues and sediment were studied over time. Although removal rates were different, the three metals were efficiently removed from water. Leaf and root tissues showed high metal concentration. However, the sediment showed the highest accumulation. During the first hours of contact, metals were not only accumulated by sediment and roots but they were also taken up by the leaves in direct contact with the solution. Over time, metals were translocated from roots to leaves and vice versa. Metals caused growth inhibition and a decrease in chlorophyll concentration and affected anatomical parameters. Despite these sub-lethal effects, T. domingensis demonstrated that it could accumulate Cr, Ni and Zn efficiently and survive an accidental dump of high concentrations of contaminants in systems such as natural and constructed wetlands. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Tolerance to systemic isotretinoin therapy in two patients using highly wettable contact lenses.

    Science.gov (United States)

    Arman, Ayşegül; Demirseren, D Deniz; Akoglu, Gulsen

    2014-01-01

    Purpose. Numerous ocular side effects have been reported with the use of systemic isotretinoin therapy. Herein, we presented two contact lens user patients who did not have contact lens intolerance during systemic isotretinoin therapy. Methods. 25-year-old male and 20-year-old female patients with severe acne vulgaris who were using highly wettable silicone hydrogel contact lenses which increase tear film stability were examined. Tear film function tests including Schirmer tests and tear break up time (TBUT) test and ocular surface staining with fluorescein were done. Subjective ocular complaints were scored with ocular surface disease index (OSDI) questionnaire. Patients were followed up monthly and examinations were repeated at each visit. Results. Both patients completed the therapy after a cumulative dose of 140 mg/kg isotretinoin in 6 months. The OSDI score and tear film function tests before and after treatment were all within normal limits. Discussion. Highly wettable contact lenses that provide increase in the tear film stability may be used during systemic retinoid therapy under close followups. Although isotretinoin affects ocular glands, the differences between tolerances to this retinoid therapy need to be investigated in larger patient groups using contact lenses.

  8. Tolerance to Systemic Isotretinoin Therapy in Two Patients Using Highly Wettable Contact Lenses

    Directory of Open Access Journals (Sweden)

    Ayşegül Arman

    2014-01-01

    Full Text Available Purpose. Numerous ocular side effects have been reported with the use of systemic isotretinoin therapy. Herein, we presented two contact lens user patients who did not have contact lens intolerance during systemic isotretinoin therapy. Methods. 25-year-old male and 20-year-old female patients with severe acne vulgaris who were using highly wettable silicone hydrogel contact lenses which increase tear film stability were examined. Tear film function tests including Schirmer tests and tear break up time (TBUT test and ocular surface staining with fluorescein were done. Subjective ocular complaints were scored with ocular surface disease index (OSDI questionnaire. Patients were followed up monthly and examinations were repeated at each visit. Results. Both patients completed the therapy after a cumulative dose of 140 mg/kg isotretinoin in 6 months. The OSDI score and tear film function tests before and after treatment were all within normal limits. Discussion. Highly wettable contact lenses that provide increase in the tear film stability may be used during systemic retinoid therapy under close followups. Although isotretinoin affects ocular glands, the differences between tolerances to this retinoid therapy need to be investigated in larger patient groups using contact lenses.

  9. A novel gene, lstC, of Listeria monocytogenes is implicated in high salt tolerance.

    Science.gov (United States)

    Burall, Laurel S; Simpson, Alexandra C; Chou, Luoth; Laksanalamai, Pongpan; Datta, Atin R

    2015-06-01

    Listeria monocytogenes, causative agent of human listeriosis, has been isolated from a wide variety of foods including deli meats, soft cheeses, cantaloupes, sprouts and canned mushrooms. Standard control measures for restricting microbial growth such as refrigeration and high salt are often inadequate as L. monocytogenes grows quite well in these environments. In an effort to better understand the genetic and physiological basis by which L. monocytogenes circumvents these controls, a transposon library of L. monocytogenes was screened for changes in their ability to grow in 7% NaCl and/ or at 5 °C. This work identified a transposon insertion upstream of an operon, here named lstABC, that led to a reduction in growth in 7% NaCl. In-frame deletion studies identified lstC which codes for a GNAT-acetyltransferase being responsible for the phenotype. Transcriptomic and RT-PCR analyses identified nine genes that were upregulated in the presence of high salt in the ΔlstC mutant. Further analysis of lstC and the genes affected by ΔlstC is needed to understand LstC's role in salt tolerance. Published by Elsevier Ltd.

  10. A CMOS high resolution, process/temperature variation tolerant RSSI for WIA-PA transceiver

    Science.gov (United States)

    Tao, Yang; Yu, Jiang; Jie, Li; Jiangfei, Guo; Hua, Chen; Jingyu, Han; Guiliang, Guo; Yuepeng, Yan

    2015-08-01

    This paper presents a high resolution, process/temperature variation tolerant received signal strength indicator (RSSI) for wireless networks for industrial automation process automation (WIA-PA) transceiver fabricated in 0.18 μm CMOS technology. The active area of the RSSI is 0.24 mm2. Measurement results show that the proposed RSSI has a dynamic range more than 70 dB and the linearity error is within ±0.5 dB for an input power from -70 to 0 dBm (dBm to 50 Ω), the corresponding output voltage is from 0.81 to 1.657 V and the RSSI slope is 12.1 mV/dB while consuming all of 2 mA from a 1.8 V power supply. Furthermore, by the help of the integrated compensation circuit, the proposed RSSI shows the temperature error within ±1.5 dB from -40 to 85 °C, and process variation error within ±0.25 dB, which exhibits good temperature-independence and excellent robustness against process variation characteristics. Project supported by the National High Technology Research and Development Program of China (No. 2011AA040102).

  11. Coil Design for High Misalignment Tolerant Inductive Power Transfer System for EV Charging

    Directory of Open Access Journals (Sweden)

    Kafeel Ahmed Kalwar

    2016-11-01

    Full Text Available The inductive power transfer (IPT system for electric vehicle (EV charging has acquired more research interest in its different facets. However, the misalignment tolerance between the charging coil (installed in the ground and pick-up coil (mounted on the car chassis, has been a challenge and fundamental interest in the future market of EVs. This paper proposes a new coil design QDQ (Quad D Quadrature that maintains the high coupling coefficient and efficient power transfer during reasonable misalignment. The QDQ design makes the use of four adjacent circular coils and one square coil, for both charging and pick-up side, to capture the maximum flux at any position. The coil design has been modeled in JMAG software for calculation of inductive parameters using the finite element method (FEM, and its hardware has been tested experimentally at various misaligned positions. The QDQ coils are shown to be capable of achieving good coupling coefficient and high efficiency of the system until the misalignment displacement reaches 50% of the employed coil size.

  12. The uropathogenic species Staphylococcus saprophyticus tolerates a high concentration of D-serine.

    Science.gov (United States)

    Sakinç, Türkân; Michalski, Nadine; Kleine, Britta; Gatermann, Sören G

    2009-10-01

    Human urine contains a relatively high concentration of d-serine, which is toxic to several nonuropathogenic bacteria, but can be utilized or detoxified by uropathogenic Escherichia coli (UPEC). The sequenced genome of uropathogenic Staphylococcus saprophyticus contains a gene with homology to the d-serine deaminase gene (dsdA) of UPEC. We found the gene in several clinical isolates of S. saprophyticus; however, the gene was absent in Staphylococcus xylosus and Staphylococcus cohnii, phylogenetically close relatives of S. saprophyticus, and could also not be detected in isolates of Staphylococcus aureus, Staphylococcus epidermidis and 13 other staphylococcal species. In addition, the genomes of other sequenced staphylococci do not harbor homologues of this operon. Interestingly, S. saprophyticus could grow in media supplemented with relatively high concentrations of d-serine, whereas S. aureus, S. epidermidis and other staphylococcal species could not. The association of the dsdA gene with growth in media including d-serine was proved by introducing the gene into S. aureus Newman. Given the fact that UPEC and S. saprophyticus tolerate this compound, d-serine utilization and detoxification may be a general property of uropathogenic bacteria.

  13. Effect of High Magnetic Field on Precipitating Phase Al2Cu in Al-40%Cu Alloy%强磁场对Al-40%Cu合金中Al2Cu析出相的影响

    Institute of Scientific and Technical Information of China (English)

    张天会; 晋芳伟; 任忠鸣; 徐人平

    2011-01-01

    在10T强磁场下进行了Al-40% Cu(质量分数)合金重熔凝固实验,并用金相分析方法研究了磁场对凝固组织的影响.实验结果表明,Al-40%Cu合金在10T强磁场中凝固时,析出相Al2Cu形成与磁场方向成一角度的规则排列的平面层状组织.理论分析认为:由于Al2Cu晶体在不同方向的磁化率不同,在磁场中受到磁力矩的作用而转动,晶体的易磁化轴转到能量最低的方向.且在强磁场中,Al2Cu晶粒之间的磁相互作用已达到液态分子间相互作用力的数量级,由于磁相互作用,相邻Al2Cu晶粒相互靠近,并在易磁化方向聚合生长,从而形成规则排列的平面层状组织.%Al-40% Cu Alloy was prepared under a high magnetic field. The solidification behavior of Al-40% Cu alloy was studied by optical microscope. The experimental results show that the precipitating phase Al2Cu formed alignment planar layer structure having a angle with the direction of magnetic field when Al-40% Cu alloy solidified under a high magnetic field of 10T. The theoretical analysis demonstrates that Al2 Cu crystals occur a rotation under the action of the magnetic moment caused by the susceptibility difference on different direction in the applied field, and the easy magnetization axis rotates to a direction of the lowest energy. Furthermore, the interaction among the particles can touch the order of the intermolecular force of liquor under a high magnetic field. The neighboring Al2Cu grains approach each other and grow along the easy magnetization direction due to the magnetic interaction, and then the alignment structure has been formed in the applied field.

  14. Effect of Nb Doping on High Temperature Oxidation Resistance of Ti-Al Alloyed Coatings

    Directory of Open Access Journals (Sweden)

    DAI Jing-jie

    2017-02-01

    Full Text Available Ti-Al alloyed coatings with different Nb doping contents were fabricated on TC4 titanium alloy by laser surface alloying to improve high temperature oxidation resistance of the alloy. Structures and high temperature oxidation behaviors of the alloyed coatings were analyzed and tested by X-ray diffraction (XRD, scanning electron microscope (SEM, energy dispersive spectrometer (EDS and box-type resistance furnace. The results show that the alloyed coatings consist of TiAl and Ti3Al, and no niobium compound are formed in Ti-Al-Nb alloyed coatings. The alloyed coatings are uniform and exhibit excellent metallurgical bonding with the substrates. A large amount of surface cracks and a few penetrating cracks are formed in Ti-Al alloyed coating without Nb doping, while no obvious cracks are formed in Ti-Al alloyed coating with Nb doping. The oxidation mass gains of all the alloyed coatings were significantly lower than those of the substrate. The alloyed coatings with Nb doping exhibit more excellent high temperature oxidation resistance due to the beneficial machanism of Nb doping. The mechanism of Nb doping on improving high temperature oxidation resistance of Ti-Al alloyed coatings includes reducing the defect concentration of TiO2, refining oxide grains and promoting the formation of Al2O3.

  15. High Chromium Tolerant Bacterial Strains from Palar River Basin: Impact of Tannery Pollution

    Directory of Open Access Journals (Sweden)

    K. Sundar

    2010-04-01

    Full Text Available The basic survey study on tanneries and its pollution in the Palar river basin of Vellore District showed that it has been contaminated with heavy metals especially chromium and salts. This study is to improve our understanding to find the Cr contamination level and the ecology of heavy metal tolerance of the native bacterial flora of our study area. Chromium tolerant strains were isolated from contaminated sediments, water and effluents of various tanneries. The minimum and maximum concentration of chromium sediments was in the range of 47.4 and 682.4 mg/L, with an average of 306.285 mg/L in the study area. Sixty-eight chromium resistant bacterial strains were isolated and Maximum Tolerance Concentration (MTC studies have indicated that the tolerance concentrations of the isolates were in the range of 100-3300 mg/L. These bacterial isolates were also checked for their resistance to other heavy metals like Ni, Pb, Zn, Fe and Cd. Eighty percent of the isolates showed resistance to Ni, Pb, Zn, Fe at 100 ppm level and 45% had shown resistance to Cd. The isolates also had shown tolerance to salt (NaCl up to 9%. Significant note was found in the concentration of chromium and in the chromium tolerance ability of the bacteria in the study area and these chromium tolerance bacteria can be used as the indicator for the Cr contamination.

  16. Experimental Plan and Irradiation Target Design for FeCrAl Embrittlement Screening Tests Conducted Using the High Flux Isotope Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Howard, Richard H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-26

    The objective of the FeCrAl embrittlement screening tests being conducted through the use of Oak Ridge National Laboratories (ORNL) High Flux Isotope Reactor is to provide data on the radiation-induced changes in the mechanical properties including radiation-induced hardening and embrittlement through systematic testing and analysis. Data developed on the mechanical properties will be supported by extensive microstructural evaluations to assist in the development of structure-property relationships and provide a sound, fundamental understanding of the performance of FeCrAl alloys in intense neutron radiation fields. Data and analysis developed as part of this effort will be used to assist in the determination of FeCrAl alloys as a viable material for commercial light water reactor (LWR) applications with a primary focus as an accident tolerant cladding.

  17. Fracture mechanisms assessment of a multilayer material with high strength and excellent impact toughness based on the aerospace Al 7075 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Cepeda-Jimenez, C. M.; Ruano, O. A.; Carreno, F.

    2012-11-01

    An aluminium multilayer laminate has been processed by hot rolling. It is constituted by 19 alternated layers of high-strength aluminium alloy (Al 7075-T6, 82 % vol) and thinner pure aluminium layers (Al 1050-H24, 18 % vol). The microstructure of the constituent alloys and the composition gradient across the interfaces has been characterized. The multilayer laminate and the as-received aluminium alloys have been tested at room temperature by Vickers microhardness, three-point bend test and impact Charpy test. The outstanding improvement in damage tolerance, which is 18 times higher than that for the as-received Al 7075 alloy, is due to both intrinsic and extrinsic fracture mechanisms operating in the multilayer laminate during mechanical testing. (Author) 19 refs.

  18. High-speed, high-resolution, radiation-tolerant SAR ADCs for particle physics experiments

    Science.gov (United States)

    Xu, H.; Zhou, Y.; Chiu, Y.; Gong, D.; Liu, T.; Ye, J.

    2015-04-01

    We present two CMOS 12-bit successive-approximation-register (SAR) analog-to-digital converter (ADC) designs and the total dose irradiation test results of the second, a 12-bit, 160-MS/s two-step SAR ADC in 40-nm CMOS. This second SAR ADC, which measured a 67.5-dB signal-to-noise plus distortion ratio (SNDR) and a >85-dB spurious-free dynamic range (SFDR), showed minimal degradation after being exposed to a total ionizing dose (TID) of up to 1 Mrad. The measured power consumption is 4.5 mW and 6.1 mW at 80 MS/s and 160 MS/s, respectively. The small silicon area of both ADCs also exhibits a great advantage for treating single event effects (SEE) using redundancy techniques, e.g., the triple modular redundancy (TMR), with much less concern for additional area overhead in a future upgrade than designs that occupy large silicon area. The experimental results reveal great potentials of SAR ADC implemented in scaled bulk CMOS process for the front-end digitizing applications of high-energy particle physics experiments.

  19. Tolerance to high-intensity intermittent running exercise: do oxygen uptake kinetics really matter?

    Directory of Open Access Journals (Sweden)

    Martin eBuchheit

    2012-10-01

    Full Text Available We examined the respective associations between aerobic fitness (VO2max, metabolic control (VO2 kinetics and locomotor function and various physiological responses to high-intensity intermittent running exercise (HIT in team sport players. Eleven players (30.5 ± 3.6 y performed a series of tests to determine their VO2max and the associated velocity (vVO2max, maximal sprinting speed (MSS and VO2 kinetics at exercise onset in the moderate and severe intensity domains, and during recovery (VO2τoff SEV. Cardiorespiratory variables, oxygenation and electromyography (EMG of lower limbs muscles and blood lactate concentration ([La] were collected during a standardized HIT protocol consisting in 8 sets of 10, 4-s runs. During HIT, four players could not complete more than 2 sets; the others finished at least 5 sets. Metabolic responses to the 2 first sets of HIT were negatively correlated with VO2max, vVO2max, and VO2τoff SEV (r=-0.6 to -0.8, while there was no clear relationship with the other variables. VO2, oxygenation and [La] responses to the first 2 sets of HIT were the only variables that differed between the players which could complete at least 5 sets or those who could not complete more than 2 sets. Players that managed to run at least 5 sets presented, in comparison with the others, greater v O2max (ES=+1.5(0.4;2.7, MSS(ES=+1.0(0.1;1.9 and training load (ES=+3.8 (2.8;4.9. There was no clear between-group difference in any of the VO2 kinetics measures (e.g., ES=-0.1(-1.4;1.2 for VO2τon SEV. While VO2max and vVO2max are likely determinant for HIT tolerance, the importance of VO2 kinetics as assessed in the present study appears limited in the present population. Knowing the main factors influencing tolerance to high-intensity intermittent running exercise may assist practitioners in personalizing training interventions.

  20. A miniature glucose/O{sub 2} biofuel cell with a high tolerance against ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Zhang, L. [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing (China); Graduate School of CAS, Beijing (China); Su, L. [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing (China); Ohsaka, T. [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Midori-ku, Yokohama (Japan); Mao, L.

    2009-02-15

    This study demonstrates a miniature glucose/O{sub 2} biofuel cell (BFC) with a high tolerance against physiological level of ascorbic acid (AA) by immobilising ascorbate oxidase (AAox) on both the bioanode and the biocathode. Single-walled carbon nanotube (SWNT)-modified carbon fiber microelectrodes (CFMEs) are employed as the substrate electrode for the bioanode and biocathode. Glucose dehydrogenase (GDH) and bilirubin oxidase (BOD) are used as the biocatalysts for the electro-oxidation of glucose and for the electro-reduction of oxygen, respectively. SWNTs are used as the support for the both, stably confining the electrocatalyst (i.e. polymerised methylene blue, polyMB) for the oxidation of NADH co-factor for GDH and efficiently facilitating direct electrochemistry of the cathodic biocatalyst (i.e. BOD) for O{sub 2} reduction. The prepared micro-sized GDH-based bioanode and BOD-based biocathode employed for the bioelectrocatalytic oxidation of glucose and reduction of oxygen, respectively, are further over-coated with AAox to give a miniature glucose/O{sub 2} BFC with a high tolerance against AA. The maximum power density and the open circuit voltage (OCV) of the assembled glucose/O{sub 2} BFC are 52 {mu}W cm{sup -2} and 0.60 V, respectively. These values remain unchanged with the presence of AA in solution. In the human serum containing 10 mM NAD{sup +} and under ambient air, the maximum power density and the OCV of the assembled glucose/O{sub 2} BFC with AAox immobilisation on both the bioanode and the biocathode are 35 {mu}W cm{sup -2} and 0.39 V, respectively. These values are remarkably larger than those of the glucose/O{sub 2} BFC without AAox immobilisation on both the bioanode and the biocathode. This study could offer a new route to the development of enzymatic BFCs with promising application in real biological systems. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  1. TUC 550: nueva variedad de poroto negro (Phaseolus vulgaris L. con tolerancia a la mancha angular (Phaeoisariopsis griseola TUC 550: a new variety of black bean (Phaseolus vulgaris L. with tolerance to angular leaf spot (ALS

    Directory of Open Access Journals (Sweden)

    Oscar N. Vizgarra

    disease tolerance, also drawing comparisons with TUC 500 (local cultivar used as a control. Four lines were identified, which were later evaluated as regards their reaction against different pathotypes of ALS causal agent (Phaeoisariopsis griseola, isolated from beans produced in the Argentine Republic. As a result of these studies, a new line of black bean with tolerance to ALS and high yield potential was identified: TUC 550. The new cultivar also showed good adaptation to growing conditions in NWA, the main bean production area in the country.

  2. Efficacy and safety of alirocumab in high cardiovascular risk patients with inadequately controlled hypercholesterolaemia on maximally tolerated doses of statins

    DEFF Research Database (Denmark)

    Cannon, Christopher P; Cariou, Bertrand; Blom, Dirk

    2015-01-01

    AIMS: To compare the efficacy [low-density lipoprotein cholesterol (LDL-C) lowering] and safety of alirocumab, a fully human monoclonal antibody to proprotein convertase subtilisin/kexin 9, compared with ezetimibe, as add-on therapy to maximally tolerated statin therapy in high cardiovascular ris...

  3. Synchrotron-Based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment

    Science.gov (United States)

    Plant species differ in response to high available manganese (Mn), but the mechanisms of sensitivity and tolerance are poorly understood. In solution culture, greater than or equal to 30 µM Mn decreased the growth of soybean (Glycine max), but white lupin (Lupinus albu...

  4. Soil water extraction, water use, and grain yield by drought tolerant maize on the Texas High Plains

    Science.gov (United States)

    Anticipated water shortages pose a challenge to the sustainability of maize (Zea mays L.) production on the Texas High Plains. Adoption of drought tolerant (DT) hybrids is a critical management strategy for maize production under water limited conditions. However, limited information is available co...

  5. Physiological and proteomic analyses of leaves from the halophyte Tangut Nitraria reveals diverse response pathways critical for high salinity tolerance

    Directory of Open Access Journals (Sweden)

    Tielong eCheng

    2015-02-01

    Full Text Available Soil salinization poses a serious threat to the environment and agricultural productivity worldwide. Studies on the physiological and molecular mechanisms of salinity tolerance in halophytic plants provide valuable information to enhance their salt tolerance. Tangut Nitraria is a widely distributed halophyte in saline–alkali soil in the northern areas of China. In this study, we used a proteomic approach to investigate the molecular pathways of the high salt tolerance of T. Nitraria. We analyzed the changes in biomass, photosynthesis, and redox-related enzyme activities in T. Nitraria leaves from plant seedlings treated with high salt concentration. Comparative proteomic analysis of the leaves revealed that the expression of 71 proteins was significantly altered after salinity treatments of T. Nitraria. These salinity-responsive proteins were mainly involved in photosynthesis, redox homeostasis, stress/defense, carbohydrate and energy metabolism, protein metabolism, signal transduction, and membrane transport. Results showed that the reduction of photosynthesis under salt stress was attributed to the down-regulation of the enzymes and proteins involved in the light reaction and Calvin cycle. Protein–protein interaction analysis revealed that the proteins involved in redox homeostasis, photosynthesis, and energy metabolism constructed two types of response networks to high salt stress. T. Nitraria plants developed diverse mechanisms for scavenging reactive oxygen species in their leaves to cope with stress induced by high salinity. This study provides important information regarding the salt tolerance of the halophyte T. Nitraria.

  6. Low-loss highly tolerant flip-chip couplers for hybrid integration of Si3N4 and polymer waveguides

    NARCIS (Netherlands)

    Mu, J.; Alexoudi, T.; Yong, Y.S.; Vázquez-Córdova, S.A.; Dijkstra, M.; Worhoff, K.; Duis, J.; Garcia Blanco, S.M.

    2016-01-01

    In this letter, low-loss and highly fabrication-tolerant flip-chip bonded vertical couplers under single-mode condition are demonstrated for the integration of a polymer waveguide chip onto the Si3N4/SiO2 passive platform. The passively aligned vertical couplers have a lateral misalignment between p

  7. Polygenic analysis and targeted improvement of the complex trait of high acetic acid tolerance in the yeast Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Meijnen, Jean-Paul; Randazzo, Paola; Foulquié-Moreno, María R; van den Brink, Joost; Vandecruys, Paul; Stojiljkovic, Marija; Dumortier, Françoise; Zalar, Polona; Boekhout, Teun; Gunde-Cimerman, Nina; Kokošar, Janez; Štajdohar, Miha; Curk, Tomaž; Petrovič, Uroš; Thevelein, Johan M

    2016-01-01

    BACKGROUND: Acetic acid is one of the major inhibitors in lignocellulose hydrolysates used for the production of second-generation bioethanol. Although several genes have been identified in laboratory yeast strains that are required for tolerance to acetic acid, the genetic basis of the high acetic

  8. BRS 369RF and BRS 370RF: Glyphosate tolerant, high-yielding upland cotton cultivars for central Brazilian savanna

    Directory of Open Access Journals (Sweden)

    Camilo de Lelis Morello

    2015-12-01

    Full Text Available BRS 369RF and BRS 370RF were developed by the EMBRAPA as a part of efforts to create high-yielding germplasm with combinations of transgenic traits. BRS 369RF and BRS 370RF are midseason cultivars and have yield stability, adaptation to the central Brazilian savanna, good fiber quality and tolerance to glyphosate herbicide.

  9. Synchrotron-Based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment

    Science.gov (United States)

    Plant species differ in response to high available manganese (Mn), but the mechanisms of sensitivity and tolerance are poorly understood. In solution culture, greater than or equal to 30 µM Mn decreased the growth of soybean (Glycine max), but white lupin (Lupinus albu...

  10. Polygenic analysis and targeted improvement of the complex trait of high acetic acid tolerance in the yeast Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Meijnen, Jean-Paul; Randazzo, Paola; Foulquié-Moreno, María R; van den Brink, Joost; Vandecruys, Paul; Stojiljkovic, Marija; Dumortier, Françoise; Zalar, Polona; Boekhout, Teun; Gunde-Cimerman, Nina; Kokošar, Janez; Štajdohar, Miha; Curk, Tomaž; Petrovič, Uroš; Thevelein, Johan M

    2016-01-01

    BACKGROUND: Acetic acid is one of the major inhibitors in lignocellulose hydrolysates used for the production of second-generation bioethanol. Although several genes have been identified in laboratory yeast strains that are required for tolerance to acetic acid, the genetic basis of the high acetic

  11. Tolerating Zero Tolerance?

    Science.gov (United States)

    Moore, Brian N.

    2010-01-01

    The concept of zero tolerance dates back to the mid-1990s when New Jersey was creating laws to address nuisance crimes in communities. The main goal of these neighborhood crime policies was to have zero tolerance for petty crime such as graffiti or littering so as to keep more serious crimes from occurring. Next came the war on drugs. In federal…

  12. Treatment tolerance and patient-reported outcomes favor online hemodiafiltration compared to high-flux hemodialysis in the elderly.

    Science.gov (United States)

    Morena, Marion; Jaussent, Audrey; Chalabi, Lotfi; Leray-Moragues, Hélène; Chenine, Leila; Debure, Alain; Thibaudin, Damien; Azzouz, Lynda; Patrier, Laure; Maurice, Francois; Nicoud, Philippe; Durand, Claude; Seigneuric, Bruno; Dupuy, Anne-Marie; Picot, Marie-Christine; Cristol, Jean-Paul; Canaud, Bernard

    2017-03-15

    Large cohort studies suggest that high convective volumes associated with online hemodiafiltration may reduce the risk of mortality/morbidity compared to optimal high-flux hemodialysis. By contrast, intradialytic tolerance is not well studied. The aim of the FRENCHIE (French Convective versus Hemodialysis in Elderly) study was to compare high-flux hemodialysis and online hemodiafiltration in terms of intradialytic tolerance. In this prospective, open-label randomized controlled trial, 381 elderly chronic hemodialysis patients (over age 65) were randomly assigned in a one-to-one ratio to either high-flux hemodialysis or online hemodiafiltration. The primary outcome was intradialytic tolerance (day 30-day 120). Secondary outcomes included health-related quality of life, cardiovascular risk biomarkers, morbidity, and mortality. During the observational period for intradialytic tolerance, 85% and 84% of patients in high-flux hemodialysis and online hemodiafiltration arms, respectively, experienced at least one adverse event without significant difference between groups. As exploratory analysis, intradialytic tolerance was also studied, considering the sessions as a statistical unit according to treatment actually received. Over a total of 11,981 sessions, 2,935 were complicated by the occurrence of at least one adverse event, with a significantly lower occurrence in online hemodiafiltration with fewer episodes of intradialytic symptomatic hypotension and muscle cramps. By contrast, health-related quality of life, morbidity, and mortality were not different in both groups. An improvement in the control of metabolic bone disease biomarkers and β2-microglobulin level without change in serum albumin concentration was observed with online hemodiafiltration. Thus, overall outcomes favor online hemodiafiltration over high-flux hemodialysis in the elderly.

  13. High vanillin tolerance of an evolved Saccharomyces cerevisiae strain owing to its enhanced vanillin reduction and antioxidative capacity.

    Science.gov (United States)

    Shen, Yu; Li, Hongxing; Wang, Xinning; Zhang, Xiaoran; Hou, Jin; Wang, Linfeng; Gao, Nan; Bao, Xiaoming

    2014-11-01

    The phenolic compounds present in hydrolysates pose significant challenges for the sustainable lignocellulosic materials refining industry. Three Saccharomyces cerevisiae strains with high tolerance to lignocellulose hydrolysate were obtained through ethyl methanesulfonate mutation and adaptive evolution. Among them, strain EMV-8 exhibits specific tolerance to vanillin, a phenolic compound common in lignocellulose hydrolysate. The EMV-8 maintains a specific growth rate of 0.104 h(-1) in 2 g L(-1) vanillin, whereas the reference strain cannot grow. Physiological studies revealed that the vanillin reduction rate of EMV-8 is 1.92-fold higher than its parent strain, and the Trolox equivalent antioxidant capacity of EMV-8 is 15 % higher than its parent strain. Transcriptional analysis results confirmed an up-regulated oxidoreductase activity and antioxidant activity in this strain. Our results suggest that enhancing the antioxidant capacity and oxidoreductase activity could be a strategy to engineer S. cerevisiae for improved vanillin tolerance.

  14. CRSM-38, a new high yielding coupled with CLCuV tolerance cotton ...

    African Journals Online (AJOL)

    Yomi

    2012-03-06

    Mar 6, 2012 ... components were under the control of additive genetic effects, whereas tolerance to CLCuV .... system which is mandatory for the release of a variety in Pakistan. ... fiber strength, insect pest attack, different doses of fertilizers,.

  15. Tolerance to high-intensity intermittent running exercise: do oxygen uptake kinetics really matter?

    Science.gov (United States)

    Buchheit, Martin; Hader, Karim; Mendez-Villanueva, Alberto

    2012-01-01

    We examined the respective associations between aerobic fitness ([Formula: see text]max), metabolic control ([Formula: see text] kinetics) and locomotor function, and various physiological responses to high-intensity intermittent (HIT) running exercise in team sport players. Eleven players (30.5 ± 3.6 year) performed a series of tests to determine their [Formula: see text]max and the associated velocity (v[Formula: see text]max), maximal sprinting speed (MSS) and [Formula: see text] kinetics at exercise onset in the moderate and severe intensity domains, and during recovery ([Formula: see text] SEV). Cardiorespiratory variables, oxygenation and electromyography of lower limbs muscles and blood lactate ([La]) concentration were collected during a standardized HIT protocol consisting in 8 sets of 10, 4-s runs. During HIT, four players could not complete more than two sets; the others finished at least five sets. Metabolic responses to the two first sets of HIT were negatively correlated with [Formula: see text]max, v[Formula: see text]max, and [Formula: see text] SEV (r = -0.6 to -0.8), while there was no clear relationship with the other variables. [Formula: see text], oxygenation and [La] responses to the first two sets of HIT were the only variables that differed between the players which could complete at least five sets or those who could not complete more than two sets. Players that managed to run at least five sets presented, in comparison with the others, greater v[Formula: see text]max [ES = +1.5(0.4; 2.7), MSS(ES = +1.0(0.1; 1.9)] and training load [ES = +3.8 (2.8; 4.9)]. There was no clear between-group difference in any of the [Formula: see text] kinetics measures [e.g., ES = -0.1(-1.4; 1.2) for [Formula: see text] SEV]. While [Formula: see text]max and v[Formula: see text]max are likely determinant for HIT tolerance, the importance of [Formula: see text] kinetics as assessed in this study appears limited in the present population. Knowing the main

  16. Tolerance to high-intensity intermittent running exercise: do oxygen uptake kinetics really matter?

    Science.gov (United States)

    Buchheit, Martin; Hader, Karim; Mendez-Villanueva, Alberto

    2012-01-01

    We examined the respective associations between aerobic fitness (V˙O2max), metabolic control (V˙O2 kinetics) and locomotor function, and various physiological responses to high-intensity intermittent (HIT) running exercise in team sport players. Eleven players (30.5 ± 3.6 year) performed a series of tests to determine their V˙O2max and the associated velocity (vV˙O2max), maximal sprinting speed (MSS) and V˙O2 kinetics at exercise onset in the moderate and severe intensity domains, and during recovery (V˙O2τoff SEV). Cardiorespiratory variables, oxygenation and electromyography of lower limbs muscles and blood lactate ([La]) concentration were collected during a standardized HIT protocol consisting in 8 sets of 10, 4-s runs. During HIT, four players could not complete more than two sets; the others finished at least five sets. Metabolic responses to the two first sets of HIT were negatively correlated with V˙O2max, vV˙O2max, and V˙O2τoff SEV (r = −0.6 to −0.8), while there was no clear relationship with the other variables. V˙O2, oxygenation and [La] responses to the first two sets of HIT were the only variables that differed between the players which could complete at least five sets or those who could not complete more than two sets. Players that managed to run at least five sets presented, in comparison with the others, greater vV˙O2max [ES = +1.5(0.4; 2.7), MSS(ES = +1.0(0.1; 1.9)] and training load [ES = +3.8 (2.8; 4.9)]. There was no clear between-group difference in any of the V˙O2 kinetics measures [e.g., ES = −0.1(−1.4; 1.2) for V˙O2τon SEV]. While V˙O2max and vV˙O2max are likely determinant for HIT tolerance, the importance of V˙O2 kinetics as assessed in this study appears limited in the present population. Knowing the main factors influencing tolerance to HIT running exercise may assist practitioners in personalizing training interventions. PMID:23097642

  17. Level-1 Data Driver Card - A high bandwidth radiation tolerant aggregator board for detectors

    CERN Document Server

    Gkountoumis, Panagiotis; The ATLAS collaboration

    2017-01-01

    The Level-1 Data Driver Card (L1DDC) was designed for the needs of the future upgrades of the innermost stations of the ATLAS end-cap muon spectrometer. The L1DDC is a high speed aggregator board capable of communicating with multiple front-end electronic boards. It collects the Level-1 data along with monitoring data and transmits them to a network interface through bidirectional and/or unidirectional fiber links at 4.8 Gbps each. In addition, the L1DDC board distributes trigger, time and configuration data coming from the network interface to the front-end boards. The L1DDC is fully compatible with the Phase II upgrade where the trigger rate is expected to reach the 1 MHz. Three different types of L1DDC boards will be fabricated handling up to 10.080 Gbps of user data. It consist of custom made radiation tolerant ASICs: the GigaBit Transceiver (GBTx), the FEAST DC-DC converter, the Slow Control Adapter (SCA), and the Versatile Tranceivers (VTRX) and transmitters (VTTX). The overall scheme of the data acquis...

  18. Thioetherification of chloroheteroarenes: a binuclear catalyst promotes wide scope and high functional-group tolerance.

    Science.gov (United States)

    Platon, Mélanie; Wijaya, Novi; Rampazzi, Vincent; Cui, Luchao; Rousselin, Yoann; Saeys, Mark; Hierso, Jean-Cyrille

    2014-09-22

    A constrained binuclear palladium catalyst system affords selective thioetherification of a wide range of functionalized arenethiols with chloroheteroaromatic partners with the highest turnover numbers (TONs) reported to date and tolerates a large variety of reactive functions. The scope of this system includes the coupling of thiophenols with six- and five-membered 2-chloroheteroarenes (i.e., functionalized pyridine, pyrazine, quinoline, pyrimidine, furane, and thiazole) and 3-bromoheteroarenes (i.e., pyridine and furane). Electron-rich congested thiophenols and fluorinated thiophenols are also suitable partners. The coupling of unprotected amino-2-chloropyridines with thiophenol and the successful employment of synthetically valuable chlorothiophenols are described with the same catalyst system. DFT studies attribute the high performance of this binuclear palladium catalyst to the decreased stability of thiolate-containing resting states. Palladium loading was as low as 0.2 mol %, which is important for industrial application and is a step forward in solving catalyst activation/deactivation problems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Comparative study on the charge-trapping properties of TaAlO and ZrAlO high-k composites with designed band alignment

    Directory of Open Access Journals (Sweden)

    W. Lu

    2015-08-01

    Full Text Available The charge-trapping memory (CTM structures Pt/Al2O3/TaAlO/Al2O3/p-Si and Pt/Al2O3/ZrAlO/Al2O3/p-Si were fabricated by using rf-sputtering and atomic layer deposition techniques, in which the potentials at the bottom of the conduction band (PBCB of high-k composites TaAlO and ZrAlO were specially designed. With a lower PBCB difference between TaAlO and p-Si than that between ZrAlO and p-Si, TaAlO CTM device shows a better charge-trapping performance. A density of trapped charges 2.88 × 1013/cm2 at an applied voltage of ±7 V was obtained for TaAlO CTM device, and it could keep about 60% of initially trapped charges after 10 years. It was suggested that the PBCB difference between high-k composite and p-Si dominates their charge-trapping behaviors.

  20. On the Breeding of Bivoltine Breeds of the Silkworm, Bombyx mori L. (Lepidoptera: Bombycidae, Tolerant to High Temperature and High Humidity Conditions of the Tropics

    Directory of Open Access Journals (Sweden)

    Harjeet Singh

    2010-01-01

    Full Text Available The hot climatic conditions of tropics prevailing particularly in summer are contributing to the poor performance of the bivoltine breeds and the most important aspect is that many quantitative characters such as viability and cocoon traits decline sharply when temperature is high. Hence, in a tropical country like India, it is very essential to develop bivoltine breeds/hybrids which can withstand the high temperature stress conditions. This has resulted in the development of CSR18 × CSR19, compatible hybrid for rearing throughout the year by utilizing Japanese thermotolerant hybrids as breeding resource material. Though, the introduction of CSR18 × CSR19 in the field during summer months had considerable impact, the productivity level and returns realized do not match that of other productive CSR hybrids. Therefore, the acceptance level of this hybrid with the farmers was not up to the expected level. This has necessitated the development of a temperature tolerant hybrid with better productivity traits than CSR18 × CSR19. Though, it was a difficult task to break the negative correlation associated with survival and productivity traits, attempts on this line had resulted in the development of CSR46 × CSR47, a temperature tolerant bivoltine hybrid with better productivity traits than CSR18 × CSR19. However, though, these hybrids are tolerant to high temperature environments, they are not tolerant to many of the silkworm diseases. Keeping this in view, an attempt is made to develop silkworm hybrids tolerant to high temperature environments.

  1. Dependence of ohmic contact properties on AlGaN layer thickness for AlGaN/GaN high-electron-mobility transistors

    Science.gov (United States)

    Takei, Yusuke; Tsutsui, Kazuo; Saito, Wataru; Kakushima, Kuniyuki; Wakabayashi, Hitoshi; Iwai, Hiroshi

    2016-04-01

    The dependence of ohmic contact resistance on the AlGaN layer thickness was evaluated for AlGaN/GaN high-electron-mobility transistor (HEMT) structures. Mo/Al/Ti contacts were formed on AlGaN layers with various thicknesses. The observed resistance characteristics are discussed on the basis of a model in which the overall contact resistance is composed of a series of three resistance components. Different dependences on the AlGaN layer thickness was observed after annealing at low temperatures (800-850 °C) and at high temperatures (900-950 °C). It was determined that lowering the resistance at the metal/AlGaN interface and that of the AlGaN layer is important for obtaining low-resistance ohmic contacts.

  2. High speed twin roll casting of Al-3Si-0.6Mg strip

    OpenAIRE

    Haga, T.; Ikawa, M; H.Watari; S. Kumai

    2006-01-01

    Purpose: Purpose of this paper is to clear the possibility of high speed roll casting of thin strip of Al-3%Si-0.6%Mg alloy. Investigation of the mechanical properties of the roll cast Al-3%Si-0.6%Mg strip was purpose, too.Design/methodology/approach: Method used in the present study was high speed twin roll caster and low temperature casting. These methods were used to realize rapid solidification, and increase of casting speed.Findings: Findings are that Al-3%Si-0.6%Mg was could be cast at ...

  3. High speed twin roll casting of recycled Al-3Si-0.6Mg strip

    OpenAIRE

    S. Kumai; H.Watari; Ikawa, M; Haga, T.

    2007-01-01

    Purpose: Purpose of this paper is to clear the possibility of high speed roll casting of thin strip of recycled Al-3%Si-0.6%Mg alloy. Investigation of the mechanical properties of the roll cast recycled Al-3%Si-0.6%Mg strip was purpose, too.Design/methodology/approach: Method used in the present study was high speed twin roll caster and low temperature casting. These methods were used to realize rapid solidification, and increase of casting speed.Findings: Findings are that recycled Al-3%Si-0...

  4. Aging Behavior of High-Strength Al Alloy 2618 Produced by Selective Laser Melting

    Science.gov (United States)

    Casati, Riccardo; Lemke, Jannis Nicolas; Alarcon, Adrianni Zanatta; Vedani, Maurizio

    2017-02-01

    High Si-bearing Al alloys are commonly used in additive manufacturing, but they have moderate mechanical properties. New high-strength compositions are necessary to spread the use of additively manufactured Al parts for heavy-duty structural applications. This work focuses on the microstructure, mechanical behavior, and aging response of an Al alloy 2618 processed by selective laser melting. Calorimetric analysis, electron microscopy, and compression tests were performed in order to correlate the mechanical properties with the peculiar microstructure induced by laser melting and thermal treatments

  5. High-performance AlGaInP light-emitting diodes

    Science.gov (United States)

    Maranowski, Steven A.; Camras, Michael D.; Chen, Changhua; Cook, Lou W.; Craford, M. G.; DeFevere, Dennis C.; Fletcher, Robert M.; Hofler, Gloria E.; Kish, Frederick A.; Kuo, Chihping; Moll, A. J.; Osentowski, Tim; Park, K. G.; Peanasky, Michael J.; Rudaz, S. L.; Steigerwald, Dan A.; Steranka, Frank M.; Stockman, Steve A.; Tan, I. H.; Tarn, J.; Yu, Jingxi; Ludowise, Mike J.; Robbins, Virginia M.

    1997-04-01

    A new class of LEDs based on the AlGaInP material system first became commercially available in the early 1990's. These devices benefit from a direct bandgap from the red to the yellow-green portion of the spectrum. The high efficiencies possible in AlGaInP across this spectrum have enabled new applications for LEDs including automotive lighting, outdoor variable message signs, outdoor large screen video displays, and traffic signal lights. A review of high-brightness AlGaInP LED technology will be presented.

  6. Effects of high and low temperatures on thermal tolerance in Folsomia candida (Collembola)

    DEFF Research Database (Denmark)

    Jensen, Dorthe; Holmstrup, Martin; Bayley, Mark

    2008-01-01

    on invertebrates, significant increases in thermal resistance have been shown to occur on this short timescale after exposure to environmentally realistic alterations in temperature (e.g. Dahlgaard et al., 1998). In the present study, the thermal shock tolerance of adult F. candida was tested after either exposure...... to a constant temperature (control) or exposure to a fluctuating temperature for between 4 and 24 h. Both ends of the thermal tolerance scale were tested. Temperature fluctuation between - 1 and 19.8 °C (± 0.1 °C) had no significant effect on the survival of F. candida after a 2-hour cold shock at - 5.4 (100......% survival), - 6.4 or - 7.4 °C (100% mortality) compared with the control. In contrast, fluctuation between 20 and 30.1 °C (± 0.1°C) induced a significantly increased tolerance to a 34.6 °C heat shock with survival increasing from about 10% in the controls to a maximum of 80% in the animals exposed...

  7. Fabrication of Al-Doped ZnO Film with High Conductivity Induced by Photocatalytic Activity

    Science.gov (United States)

    Hong, Jeongsoo; Katsumata, Ken-ichi; Matsushita, Nobuhiro

    2016-10-01

    We have fabricated Al-doped ZnO films by a spin-spray method, achieving high conductivity by Al-ion doping and photocatalytic activity of the ZnO. The surface morphology of the as-deposited films was varied by changing the Al concentration and addition of citrate ions. As-deposited Al-doped ZnO film without citrate ions showed rod array structure with increasing rod width as the Al concentration was increased. Meanwhile, Al-doped ZnO film deposited with addition of citrate ions changed to exhibit dense and continuous surface morphology with high transmittance of 85%. The lowest resistivity recorded for undoped and Al-doped ZnO film was 2.1 × 10-2 Ω cm and 5.9 × 10-3 Ω cm, after ultraviolet (UV) irradiation. The reason for the decreased resistivity is thought to be that Al-ion doping and the photocatalytic activity of ZnO contributed to improve the conductivity.

  8. Oxidation performance of Fe-Al/WC composite coatings produced by high velocity arc spraying

    Institute of Scientific and Technical Information of China (English)

    MENG Fan-jun; XU Bin-shi; ZHU Sheng; MA Shi-ning; ZHANG wei

    2005-01-01

    Fe-Al intermetallics with remarkable high-temperature intensity and excellent erosion, high-temperature oxidation and sulfuration resistance are potential low cost high-temperature structural materials. But the room tem perature brittleness induces shape difficult and limits its industrial application. The Fe-Al intermetallic coatings were prepared by high velocity arc spraying technology with cored wire on 20G steel, which will not only obviate the problems faced in fabrication of these alloys into useful shapes, but also allow the effective use of their outstanding high-temperature performance. The Fe-Al/WC intermetallic composite coatings were prepared by high velocity arc spraying technology on 20G steel and the oxidation performance of Fe-Al/WC composite coatings was studied by means of thermogrativmetic analyzer at 450, 650 and 800 ℃. The results demonstrate that the kinetics curve of oxidation at three temperatures approximately follows the logarithmic law. The composition of the oxidized coating is mainly composed of Al2 O3, Fe2 O3, Fe3 O4 and FeO. These phases distribute unevenly. The protective Al2 O3 film firstly forms and preserves the coatings from further oxidation.

  9. Improvement of electrical properties of AlGaN/GaN heterostructures using multiple high-temperature AlN interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Ni, J.Y. [School of Science, Xidian University, 710071 Xi' an (China); Hao, Y.; Xue, J.S.; Xu, Z.H.; Zhang, Z.F.; Zhang, J.C.; Yang, L.A.; Zhang, J.F. [Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, 710071 Xi' an (China)

    2010-07-15

    AlGaN/GaN heterostructures with multiple AlN interlayers deposited at a high-temperature (HT) of 900 C were grown by metalorganic chemical vapor deposition. Flat surface with few dark pits was obtained by using multiple HT-AlN interlayers. Hall effect measurements and non-contact sheet resistance mappings demonstrated the improvement of the electrical properties of AlGaN/GaN heterostructure. The sheet carrier density and Hall mobility continuously increased with the increase of the AlN interlayer number. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. InAlN high electron mobility transistor Ti/Al/Ni/Au Ohmic contact optimisation assisted by in-situ high temperature transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M. D.; Parbrook, P. J., E-mail: peter.parbrook@tyndall.ie [Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork T12 R5CP (Ireland); School of Engineering, University College Cork, Cork T12 YN60 (Ireland); O' Mahony, D. [Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork T12 R5CP (Ireland); Conroy, M.; Schmidt, M. [Tyndall National Institute, University College Cork, Lee Maltings, Dyke Parade, Cork T12 R5CP (Ireland); Department of Chemistry, University College Cork, Cork T12 YN60 (Ireland)

    2015-09-14

    This paper correlates the micro-structural and electrical characteristics associated with annealing of metallic multi-layers typically used in the formation of Ohmic contacts to InAlN high electron mobility transistors. The multi-layers comprised Ti/Al/Ni/Au and were annealed via rapid thermal processing at temperatures up to 925 °C with electrical current-voltage analysis establishing the onset of Ohmic (linear IV) behaviour at 750–800 °C. In-situ temperature dependent transmission electron microscopy established that metallic diffusion and inter-mixing were initiated near a temperature of 500 °C. Around 800 °C, inter-diffusion of the metal and semiconductor (nitride) was observed, correlating with the onset of Ohmic electrical behaviour. The sheet resistance associated with the InAlN/AlN/GaN interface is highly sensitive to the anneal temperature, with the range depending on the Ti layer thickness. The relationship between contact resistivity and measurement temperature follow that predicted by thermionic field emission for contacts annealed below 850 °C, but deviated above this due to excessive metal-semiconductor inter-diffusion.

  11. RESTING SYMPATHETIC BAROREFLEX SENSITIVITY IN SUBJECTS WITH LOW AND HIGH TOLERANCE TO CENTRAL HYPOVOLEMIA INDUCED BY LOWER BODY NEGATIVE PRESSURE

    Directory of Open Access Journals (Sweden)

    Carmen eHinojosa-Laborde

    2014-06-01

    Full Text Available Central hypovolemia elicited by orthostasis or hemorrhage triggers sympathetically-mediated baroreflex responses to maintain organ perfusion; these reflexes are less sensitive in patients with orthostatic intolerance, and during conditions of severe blood loss, may result in cardiovascular collapse (decompensatory or circulatory shock. The ability to tolerate central hypovolemia is variable and physiological factors contributing to tolerance are emerging. We tested the hypothesis that resting muscle sympathetic nerve activity (MSNA and sympathetic baroreflex sensitivity (BRS are attenuated in male and female subjects who have low tolerance (LT to central hypovolemia induced by lower body negative pressure (LBNP. MSNA and diastolic arterial pressure (DAP were recorded in 47 human subjects who subsequently underwent LBNP to tolerance (onset of presyncopal symptoms. LT subjects experienced presyncopal symptoms prior to completing LBNP of -60 mm Hg, and subjects with high tolerance (HT experienced presyncopal symptoms after completing LBNP after -60 mmHg. Contrary to our hypothesis, resting MSNA burst incidence was not different between LT and HT subjects, and was not related to time to presyncope. BRS was assessed as the slope of the relationship between spontaneous fluctuations in DAP and MSNA during 5 min of supine rest. MSNA burst incidence/DAP correlations were greater than or equal to 0.5 in 37 subjects (LT: n= 9; HT: n=28, and BRS was not different between LT and HT (-1.8 ± 0.3 vs. -2.2 ± 0.2 bursts•(100 beats-1•mmHg-1, p=0.29. We conclude that tolerance to central hypovolemia is not related to either resting MSNA or sympathetic BRS.

  12. Aluminium exclusion and aluminium tolerance in woody plants

    Directory of Open Access Journals (Sweden)

    Ivano eBrunner

    2013-06-01

    Full Text Available The aluminium (Al cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al3+ from root cells (exclusion mechanisms and those that enable plants to tolerate Al3+ once it has entered the root and shoot symplast (internal tolerance mechanisms. The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al3+ exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al3+ adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

  13. Novel AlN/Pt/ZnO Electrode for High Temperature SAW Sensors

    Directory of Open Access Journals (Sweden)

    Xingpeng Liu

    2017-01-01

    Full Text Available In order to develop a film electrode for the surface acoustic wave (SAW devices working in high temperature, harsh environments, novel AlN/Pt/ZnO multilayers were prepared using pulsed laser deposition (PLD systems on langasite (LGS substrates. The AlN film was used as a protective layer and the ZnO buffer layer was introduced to improve the crystal quality of Pt films. The results show that the resistances of Pt and AlN/Pt film electrodes violently increase above 600 °C and 800 °C, respectively, while the resistances of AlN/Pt/ZnO electrodes have more stable electrical resistance from room temperature to 1000 °C. The AlN/Pt/ZnO electrode, where the ZnO film was deposited at 600 °C, has the best temperature stability and can steadily work for 4 h at 1000 °C. The mechanism underlying the stable resistance of the AlN/Pt/ZnO electrode at a high temperature was investigated by analyzing the microstructure of the prepared samples. The proposed AlN/Pt/ZnO film electrode has great potential for applications in high temperature SAW sensors.

  14. Prospección de las combinaciones de herbicidas para prevenir malezas tolerantes y resistentes al glifosato Exploration of herbicide associations to prevent glyphosate tolerant and resistant weeds

    Directory of Open Access Journals (Sweden)

    R.A. VIDAL

    2010-01-01

    Full Text Available El intenso empleo de glifosato contribuyó a la difusión de malezas con tolerancia a este herbicida, incluyendo especies como Ipomoea nil, bejuco en Argentina, o corriola, o corda-de-viola en Brasil. A su vez, el uso intensivo de imadozolinonas en ciertas regiones de Argentina contribuyó a la aparición de biotipos resistentes a herbicidas que actúan inhibiendo la enzima ALS como Amaranthus quitensis, yuyo colorado o ataco, conocido como carurú en Brasil. En ese país, también, aumentó la difusión de malezas con resistencia a glifosato como en Euphorbia heterophylla, leiteiro o amendoim-bravo y en Lolium multiflorum, azevém. El objetivo de esta investigación fue evaluar el antagonismo o el sinergismo de todas las combinaciones posibles entre dos de los siguientes herbicidas: glifosato, imazetapir, clomazone y lactofen, en el control de las malezas mencionadas. Biotipos susceptibles para todos herbicidas fueran usados en la investigación. Plántulas de yuyo colorado juveniles con dos cm de altura y de las otras malezas mencionadas con siete cm, fueron tratadas con los siguientes herbicidas en g ha-1 i.a.: glifosato 108; imazetapir 10; clomazone 160 y lactofen 30, aplicados solos. Otros seis tratamientos fueron incluidos en todas las combinaciones posibles entre dos de los herbicidas y dosis mencionados. También se empleó un testigo sin tratar. El efecto de la combinación de los herbicidas dependió de la especie evaluada y también de los herbicidas utilizados. Se obtuvo sinergismo solamente para la mezcla glifosato más imazetapir en ataco. Clomazone fue el herbicida con más antagonismo, y lactofen tuvo efecto neutro en la mayoría de las mezclas. Las combinaciones son consideradas potencialmente útiles en el control de malezas tolerantes o resistentes a glifosato.The intense use of glyphosate in Argentina has increased the spread of weeds with tolerance to this herbicide, like Ipomoea nil. Cases of weed resistance to ALS

  15. Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

    Science.gov (United States)

    Hui. Hejiu; Neal, Clive, R.; Shih, Chi-Yu; Nyquist, Laurence E.

    2012-01-01

    Pristine Apollo 14 (A-14) high-Al basalts represent the oldest volcanic deposits returned from the Moon [1,2] and are relatively enriched in Al2O3 (>11 wt%) compared to other mare basalts (7-11 wt%). Literature Rb-Sr isotopic data suggest there are at least three different eruption episodes for the A-14 high-Al basalts spanning the age range approx.4.3 Ga to approx.3.95 Ga [1,3]. Therefore, the high-Al basalts may record lunar mantle evolution between the formation of lunar crust (approx.4.4 Ga) and the main basin-filling mare volcanism (basalts were originally classified into five compositional groups [5,6], and then regrouped into three with a possible fourth comprising 14072 based on the whole-rock incompatible trace element (ITE) ratios and Rb-Sr radiometric ages [7]. However, Rb-Sr ages of these basalts from different laboratories may not be consistent with each other because of the use of different 87Rb decay constants [8] and different isochron derivation methods over the last four decades. This study involved a literature search for Rb-Sr isotopic data previously reported for the high-Al basalts. With the re-calculated Rb-Sr radiometric ages, eruption episodes of A-14 high-Al basalts were determined, and their petrogenesis was investigated in light of the "new" Rb-Sr isotopic data and published trace element abundances of these basalts.

  16. High-speed solar-blind UV photodetectors using high-Al content Al0.64Ga0.36N/Al0.34Ga0.66N multiple quantum wells

    Science.gov (United States)

    Muhtadi, Sakib; Hwang, Seong Mo; Coleman, Antwon L.; Lunev, Alexander; Asif, Fatima; Chava, V. S. N.; Chandrashekhar, M. V. S.; Khan, Asif

    2017-01-01

    We demonstrate high-external quantum efficiency (˜50%) solar-blind AlGaN p-n junction photodetectors with high-Al content multiple quantum wells (MQWs). A peak responsivity of 0.1 A/W at 250 nm, which falls >103 by 280 nm, indicates that the optical absorption is dominated by the MQW structures. At a reverse bias of 0.5 V, the dark current is measured as 0.4 µs, and an achievable detector RC-limited time response of 2 ns is estimated. The devices do not show internal gain, which accounts for their high speed.

  17. First-principle Calculations of Mechanical Properties of Al2Cu, Al2CuMg and MgZn2 Intermetallics in High Strength Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    LIAO Fei

    2016-12-01

    Full Text Available Structural stabilities, mechanical properties and electronic structures of Al2Cu, Al2CuMg and MgZn2 intermetallics in Al-Zn-Mg-Cu aluminum alloys were determined from the first-principle calculations by VASP based on the density functional theory. The results show that the cohesive energy (Ecoh decreases in the order MgZn2 > Al2CuMg > Al2Cu, whereas the formation enthalpy (ΔH decreases in the order MgZn2 > Al2Cu > Al2CuMg. Al2Cu can act as a strengthening phase for its ductile and high Young's modulus. The Al2CuMg phase exhibits elastic anisotropy and may act as a crack initiation point. MgZn2 has good plasticity and low melting point, which is the main strengthening phase in the Al-Zn-Mg-Cu aluminum alloys. Metallic bonding mode coexists with a fractional ionic interaction in Al2Cu, Al2CuMg and MgZn2, and that improves the structural stability. In order to improve the alloys' performance further, the generation of MgZn2 phase should be promoted by increasing Zn content while Mg and Cu contents are decreased properly.

  18. Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Matthew (DOE/NNSA Kansas City Plant (United States)); Weyant, J.; Garner, S. (Advanced Cooling Technologies, Inc. (Lancaster, PA (United States)); Occhionero, M. (CPS Technologies Corporation, Norton, MA (United States))

    2010-01-07

    Heat pipe embedded aluminum silicon carbide (AlSiC) plates are innovative heat spreaders that provide high thermal conductivity and low coefficient of thermal expansion (CTE). Since heat pipes are two phase devices, they demonstrate effective thermal conductivities ranging between 50,000 and 200,000 W/m-K, depending on the heat pipe length. Installing heat pipes into an AlSiC plate dramatically increases the plate’s effective thermal conductivity. AlSiC plates alone have a thermal conductivity of roughly 200 W/m-K and a CTE ranging from 7-12 ppm/ deg C, similar to that of silicon. An equivalent sized heat pipe embedded AlSiC plate has effective thermal conductivity ranging from 400 to 500 W/m-K and retains the CTE of AlSiC.

  19. Development of environmentally friendly cast alloys and composites. High zinc Al-base cast alloys

    Directory of Open Access Journals (Sweden)

    W.K. Krajewski

    2010-01-01

    Full Text Available This work is devoted to grain refinement of the foundry Al-20 wt% Zn (AlZn20 alloy, aiming at improving ductility of the sand-cast alloy The melted alloy was inoculated using traditional AlTi5B1 (TiBAl and AlTi3C0.15 (TiCAl master alloys and newly introduced (Zn,Al-Ti3 one. The performed structural examinations showed out significant increasing of the grain population of the inoculated alloy and plas-ticity increase represented by elongation. The high damping properties of the initial alloy, measured using an ultrasonic Olympus Epoch XT device, are basicly preserved after inoculation. Also tensile strength preserves its good values, while elongation shows an increase – which are beneficials of the employed grain-refining process.

  20. Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

    Science.gov (United States)

    Lee, Jonathan A.

    2009-01-01

    In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

  1. Dopant-Free GaN/AlN/AlGaN Radial Nanowire Heterostructures as High Electron Mobility Transistors

    Science.gov (United States)

    2016-06-07

    heterostructures. In summary, we have synthesized dislocation-free single- crystal GaN/AlN/Al0 25Ga0 75N nanowire heterostructures with well-controlled...were synthesized on a c-plane Al2O3 substrate in a MOCVD reactor (Thomas Swan Scientific Equipment Ltd.) using trimethylgallium, trimethylaluminium...and ammonia as Ga, Al, and N sources, respectively. We deposited 0.01 M nickel nitrate solution as the nickel nanocluster precursor. GaN cores were

  2. State of the art in high accuracy high detail DTMs derived from ALS

    Science.gov (United States)

    Pfeifer, N.; Briese, C.; Mandlburger, G.; Höfle, B.; Ressl, C.

    2009-04-01

    High-resolution Digital Terrain Models (DTMs) representing the bare Earth are a fundamental input for various applications in geomorphology. Airborne laser scanning (ALS) is established as a standard tool for deriving DTMs over large areas with unprecedented accuracy. Due to advances in sensor technology and in processing algorithms in the recent years the obtainable accuracy is still increasing. Accuracy is understood as the deviation from the elevation at one specified point to its true value. These advances may lead to a more efficient data acquisition, if reduced accuracy is targeted, but also allow data acquisition schemes with more detail becoming visible, i.e. small features of the relief. For the latter a high internal precision, i.e. repeatability, is necessary. The essential advances in the technologies are improvements in ranging through the introduction of full-waveform (FWF) laser scanning and rigorous models of strip adjustment. In FWF laser scanning the time-dependent strength of the backscattered signal is recorded. This is opposed to the analogue processing of the incoming energy and storage of one arrival time of discrete-return systems. In a simple one-echo situation, the arrival time corresponds to the maximum of the waveform. By applying a decomposition of the full waveform into single echoes, which are transformed copies of the emitted signal, it is possible to retrieve more echoes per shot. Additionally, if echoes of individual scatterers are overlapping, FWF sensors might be able to separate them, whereas discrete return systems might rather only be able to derive one collective arrival time. Finally, the overlay of two echoes does not have the maxima at the same positions as the individual echoes. Additionally, the pulse repetition rate of laser scanners has increased, which allows higher point densities and therefore higher richness of detail. These advances in data acquisition increase the precision within one ALS strip. Deficiencies in

  3. Highly Efficient Four-Wave Mixing in an AlGaAs-On-Insulator (AlGaAsOI) Nano-Waveguide

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta

    2015-01-01

    We propose an AlGaAs-on-insulator platform for nonlinear integrated photonics. We demonstrate highly efficient four-wave mixing in a 3-mm long AlGaAs-on-insulator nanowaveguide. A conversion efficiency of -21.1 dB is obtained with only a 45-mW pump......We propose an AlGaAs-on-insulator platform for nonlinear integrated photonics. We demonstrate highly efficient four-wave mixing in a 3-mm long AlGaAs-on-insulator nanowaveguide. A conversion efficiency of -21.1 dB is obtained with only a 45-mW pump...

  4. Experimental evidences for reducing Mg activation energy in high Al-content AlGaN alloy by MgGa δ doping in (AlN)m/(GaN)n superlattice

    Science.gov (United States)

    Wang, Xiao; Wang, Wei; Wang, Jingli; Wu, Hao; Liu, Chang

    2017-01-01

    P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences were achieved by analyzing Mg doped high Al-content AlGaN alloys and Mg doped AlGaN SLs as well as MgGa δ doped AlGaN SLs. Mg acceptor activation energy was significantly reduced from 0.378 to 0.331 eV by using MgGa δ doping in SLs instead of traditional doping in alloys. This new process was confirmed to be able to realize high p-type doping in high Al-content AlGaN. PMID:28290480

  5. Use of nitrogen gas in high-speed milling of Ti-6Al-4V

    Institute of Scientific and Technical Information of China (English)

    KE Ying-lin; DONG Hui-yue; LIU Gang; ZHANG Ming

    2009-01-01

    To inhibit chips burning in the high-speed cutting of Ti-6Al-4V, nitrogen gas with 0.7 MPa pressure was ejected at the milling zone. The high speed flowing of nitrogen gas speeds up the chips leaving, and prevents the chips from burning at the same time. By this method the cutting force is reduced. Especially, the temperature increment of the finished surface is smaller than 5 ℃. This prevents the increase of hardness, improves the roughness of the finished surface, and reduces the tools wear. Comparing and analyzing the morphology and color of chips, which are obtained from the high-speed machining of Ti-6Al-4V with and without nitrogen gas ejection, show the action mechanism of nitrogen gas during the high-speed machining of titanium alloy, and it is concluded that nitrogen gas can be used to realize the proper high-speed milling of Ti-6Al-4V titanium alloy.

  6. High-pressure polymorphism as a step towards high density structures of LiAlH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiaoli; Duan, Defang; Li, Xin; Li, Fangfei; Huang, Yanping; Wu, Gang; Liu, Yunxian; Zhou, Qiang; Liu, Bingbing; Cui, Tian, E-mail: cuitian@jlu.edu.cn [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China)

    2015-07-27

    Two high density structures β- and γ-LiAlH{sub 4} are detected in LiAlH{sub 4}, a promising hydrogen storage compound, upon compression in diamond anvil cells, investigated with synchrotron X-ray diffraction and first-principle calculations. The joint of the experimental and theoretical results has confirmed the sequence of the pressure-induced structural phase transitions from α-LiAlH{sub 4} (space group P2{sub 1}/c) to β-LiAlH{sub 4} (P2{sub 1}/c-6C symmetry), and then to γ-LiAlH{sub 4} (space group Pnc2), which are not reported in previous literatures. At the α to β transition point for LiAlH{sub 4}, the estimated difference in cell volume is about 20%, while the transformation from β to γ phase is with a volume drop smaller than 1%. The α to β phase transition is accompanied by the local structure change from a AlH{sub 4} tetrahedron into a AlH{sub 6} octahedron, which contributes to a large volume collapse.

  7. The Dilatometric Analysis of the High Carbon Alloys from Ni-Ta-Al-M System

    Directory of Open Access Journals (Sweden)

    Bała P.

    2014-10-01

    Full Text Available In the following work presents results of high carbon alloys from the Ni-Ta-Al-M system are presented. The alloys have been designed to have a good tribological properties at elevated temperatures. Despite availability of numerous hot work tool materials there is still a growing need for new alloys showing unique properties, which could be used under heavy duty conditions, i.e. at high temperatures, in a chemically aggressive environment and under heavy wear conditions. A characteristic, coarse-grained dendritic microstructure occurs in the investigated alloys in the as-cast condition. Primary dendrites with secondary branches can be observed. Tantalum carbides of MC type and graphite precipitations are distributed in interdendritic spaces in the Ni-Ta-Al-C and Ni-Ta-Al-C-Co alloys, while Tantalum carbides of MC type and Chromium carbides of M7C3 type appeared in the Ni-Ta-Al-C-Co-Cr and Ni-Ta-Al-C-Cr alloys. In all alloys g’ phase is present, however, its volume fraction in the Ni-Ta-Al-C and Ni-Ta-Al-C-Co alloys is small.

  8. Pt-Al2O3 nanocoatings for high temperature concentrated solar thermal power applications

    Science.gov (United States)

    Nuru, Zebib. Y.; Arendse, C. J.; Nemutudi, R.; Nemraoui, O.; Maaza, M.

    2012-05-01

    Nano-phased structures based on metal-dielectric composites, also called cermets (ceramic-metal), are considered among the most effective spectral selective solar absorbers. For high temperature applications (stable up to 650 °C) noble metal nanoparticles and refractory oxide host matrices are ideal as per their high temperature chemical inertness and stability: Pt/Al2O3 cermet nano-composites are a representative family. This contribution reports on the optical properties of Pt/Al2O3 cermet nano-composites deposited in a multilayered tandem structure. The radio-frequency sputtering optimized Pt/Al2O3 solar absorbers consist of stainless steel substrate/ Mo coating layer/ Pt-Al2O3/ protective Al2O3 layer and stainless steel substrate/ Mo coating layer /Pt-Al2O3 for different composition and thickness of the Pt-Al2O3 cermet coatings. The microstructure, morphology, theoretical modeling and optical properties of the coatings were analyzed by the x-ray diffraction, atomic force, microscopy, effective medium approximation and UV-vis specular and diffuse reflectance.

  9. Thermal treatment and utilization of Al-rich waste in high calcium fly ash geopolymeric materials

    Science.gov (United States)

    Chindaprasirt, Prinya; Rattanasak, Ubolluk; Vongvoradit, Pimdao; Jenjirapanya, Supichart

    2012-09-01

    The Al-rich waste with aluminium and hydrocarbon as the major contaminant is generated at the wastewater treatment unit of a polymer processing plant. In this research, the heat treatment of this Al-rich waste and its use to adjust the silica/alumina ratio of the high calcium fly ash geopolymer were studied. To recycle the raw Al-rich waste, the waste was dried at 110°C and calcined at 400 to 1000°C. Mineralogical analyses were conducted using X-ray diffraction (XRD) to study the phase change. The increase in calcination temperature to 600, 800, and 1000°C resulted in the phase transformation. The more active alumina phase of active γ-Al2O3 was obtained with the increase in calcination temperature. The calcined Al-rich waste was then used as an additive to the fly ash geopolymer by mixing with high calcium fly ash, water glass, 10 M sodium hydroxide (NaOH), and sand. Test results indicated that the calcined Al-rich waste could be used as an aluminium source to adjust the silica/alumina ratio and the strength of geopolymeric materials. The fly ash geopolymer mortar with 2.5wt% of the Al-rich waste calcined at 1000°C possessed the 7-d compressive strength of 34.2 MPa.

  10. Expression and characterization of a novel highly glucose-tolerant β-glucosidase from a soil metagenome

    Institute of Scientific and Technical Information of China (English)

    Jian Lu; Liqin Du; Yutuo Wei; Yuanyuan Hu; Ribo Huang

    2013-01-01

    A β-glucosidase gene unbgl1A was isolated by the functionbased screening of a metagenomic library and the enzyme protein was expressed in Escherichia coli,purified,and biochemically characterized.The enzyme Unbgl1A had a Km value of 2.09 ± 0.31 mM,and a Vmax value of 183.90 ± 9.61 μmol min-1 mg-1 under the optimal reaction conditions,which were pH 6.0 at 50℃.Unbgl1A can be activated by a variety of monosaccharides,disaccharides,and NaCl,and exhibits a high level of stability at high concentration of NaCl.Two prominent features for this enzyme are:(i) high glucose tolerance.It can be tolerant to glucose as high as 2000 mM,with Ki =1500 mM; (ii) high NaCl tolerance.Its activity is not affected by 600 mM NaCl.The enzyme showed transglucosylation activities resulting in the formation of cellotriose from cellobiose.These properties of Unbgl1A should have important practical implication in its potential applications for better industrial production of glucose or bioethanol started from lignocellulosic biomass.

  11. Fault Tolerant Message Efficient Coordinator Election Algorithm in High Traffic Bidirectional Ring Network

    Directory of Open Access Journals (Sweden)

    Danial Rahdari

    2012-12-01

    Full Text Available Nowadays use of distributed systems such as internet and cloud computing is growing dramatically. Coordinator existence in these systems is crucial due to processes coordinating and consistency requirement as well. However the growth makes their election algorithm even more complicated. Too many algorithms are proposed in this area but the two most well known one are Bully and Ring. In this paper we propose a fault tolerant coordinator election algorithm in typical bidirectional ring topology which is twice as fast as Ring algorithm although far fewer messages are passing due to election. Fault tolerance technique is applied which leads the waiting time for the election reaching to zero.

  12. Identification of novel causative genes determining the complex trait of high ethanol tolerance in yeast using pooled-segregant whole-genome sequence analysis

    Science.gov (United States)

    Swinnen, Steve; Schaerlaekens, Kristien; Pais, Thiago; Claesen, Jürgen; Hubmann, Georg; Yang, Yudi; Demeke, Mekonnen; Foulquié-Moreno, María R.; Goovaerts, Annelies; Souvereyns, Kris; Clement, Lieven; Dumortier, Françoise; Thevelein, Johan M.

    2012-01-01

    High ethanol tolerance is an exquisite characteristic of the yeast Saccharomyces cerevisiae, which enables this microorganism to dominate in natural and industrial fermentations. Up to now, ethanol tolerance has only been analyzed in laboratory yeast strains with moderate ethanol tolerance. The genetic basis of the much higher ethanol tolerance in natural and industrial yeast strains is unknown. We have applied pooled-segregant whole-genome sequence analysis to map all quantitative trait loci (QTL) determining high ethanol tolerance. We crossed a highly ethanol-tolerant segregant of a Brazilian bioethanol production strain with a laboratory strain with moderate ethanol tolerance. Out of 5974 segregants, we pooled 136 segregants tolerant to at least 16% ethanol and 31 segregants tolerant to at least 17%. Scoring of SNPs using whole-genome sequence analysis of DNA from the two pools and parents revealed three major loci and additional minor loci. The latter were more pronounced or only present in the 17% pool compared to the 16% pool. In the locus with the strongest linkage, we identified three closely located genes affecting ethanol tolerance: MKT1, SWS2, and APJ1, with SWS2 being a negative allele located in between two positive alleles. SWS2 and APJ1 probably contained significant polymorphisms only outside the ORF, and lower expression of APJ1 may be linked to higher ethanol tolerance. This work has identified the first causative genes involved in high ethanol tolerance of yeast. It also reveals the strong potential of pooled-segregant sequence analysis using relatively small numbers of selected segregants for identifying QTL on a genome-wide scale. PMID:22399573

  13. Comparative polygenic analysis of maximal ethanol accumulation capacity and tolerance to high ethanol levels of cell proliferation in yeast.

    Science.gov (United States)

    Pais, Thiago M; Foulquié-Moreno, María R; Hubmann, Georg; Duitama, Jorge; Swinnen, Steve; Goovaerts, Annelies; Yang, Yudi; Dumortier, Françoise; Thevelein, Johan M

    2013-06-01

    The yeast Saccharomyces cerevisiae is able to accumulate ≥17% ethanol (v/v) by fermentation in the absence of cell proliferation. The genetic basis of this unique capacity is unknown. Up to now, all research has focused on tolerance of yeast cell proliferation to high ethanol levels. Comparison of maximal ethanol accumulation capacity and ethanol tolerance of cell proliferation in 68 yeast strains showed a poor correlation, but higher ethanol tolerance of cell proliferation clearly increased the likelihood of superior maximal ethanol accumulation capacity. We have applied pooled-segregant whole-genome sequence analysis to identify the polygenic basis of these two complex traits using segregants from a cross of a haploid derivative of the sake strain CBS1585 and the lab strain BY. From a total of 301 segregants, 22 superior segregants accumulating ≥17% ethanol in small-scale fermentations and 32 superior segregants growing in the presence of 18% ethanol, were separately pooled and sequenced. Plotting SNP variant frequency against chromosomal position revealed eleven and eight Quantitative Trait Loci (QTLs) for the two traits, respectively, and showed that the genetic basis of the two traits is partially different. Fine-mapping and Reciprocal Hemizygosity Analysis identified ADE1, URA3, and KIN3, encoding a protein kinase involved in DNA damage repair, as specific causative genes for maximal ethanol accumulation capacity. These genes, as well as the previously identified MKT1 gene, were not linked in this genetic background to tolerance of cell proliferation to high ethanol levels. The superior KIN3 allele contained two SNPs, which are absent in all yeast strains sequenced up to now. This work provides the first insight in the genetic basis of maximal ethanol accumulation capacity in yeast and reveals for the first time the importance of DNA damage repair in yeast ethanol tolerance.

  14. Comparative polygenic analysis of maximal ethanol accumulation capacity and tolerance to high ethanol levels of cell proliferation in yeast.

    Directory of Open Access Journals (Sweden)

    Thiago M Pais

    2013-06-01

    Full Text Available The yeast Saccharomyces cerevisiae is able to accumulate ≥17% ethanol (v/v by fermentation in the absence of cell proliferation. The genetic basis of this unique capacity is unknown. Up to now, all research has focused on tolerance of yeast cell proliferation to high ethanol levels. Comparison of maximal ethanol accumulation capacity and ethanol tolerance of cell proliferation in 68 yeast strains showed a poor correlation, but higher ethanol tolerance of cell proliferation clearly increased the likelihood of superior maximal ethanol accumulation capacity. We have applied pooled-segregant whole-genome sequence analysis to identify the polygenic basis of these two complex traits using segregants from a cross of a haploid derivative of the sake strain CBS1585 and the lab strain BY. From a total of 301 segregants, 22 superior segregants accumulating ≥17% ethanol in small-scale fermentations and 32 superior segregants growing in the presence of 18% ethanol, were separately pooled and sequenced. Plotting SNP variant frequency against chromosomal position revealed eleven and eight Quantitative Trait Loci (QTLs for the two traits, respectively, and showed that the genetic basis of the two traits is partially different. Fine-mapping and Reciprocal Hemizygosity Analysis identified ADE1, URA3, and KIN3, encoding a protein kinase involved in DNA damage repair, as specific causative genes for maximal ethanol accumulation capacity. These genes, as well as the previously identified MKT1 gene, were not linked in this genetic background to tolerance of cell proliferation to high ethanol levels. The superior KIN3 allele contained two SNPs, which are absent in all yeast strains sequenced up to now. This work provides the first insight in the genetic basis of maximal ethanol accumulation capacity in yeast and reveals for the first time the importance of DNA damage repair in yeast ethanol tolerance.

  15. Cold, pH and salt tolerant Penicillium spp. inhabit the high altitude soils in Himalaya, India.

    Science.gov (United States)

    Dhakar, Kusum; Sharma, Avinash; Pandey, Anita

    2014-04-01

    Twenty five fungal cultures (Penicillium spp.), isolated from soil samples from the high altitudes in the Indian Himalayan region, have been characterized following polyphasic approach. Colony morphology performed on five different media gave varying results; potato dextrose agar being the best for the vegetative growth and sporulation as well. Microscopic observations revealed 18 isolates to be biverticillate and 7 monoverticillate. Based on the phenotypic characters (colony morphology and microscopy), all the isolates were designated to the genus Penicillium. Exposure to low temperature resulted in enhanced sporulation in 23 isolates, while it ceased in case of two. The fungal isolates produced watery exudates in varying amount that in many cases increased at low temperature. All the isolates could grow between 4 and 37 °C, (optimum 24 °C), hence considered psychrotolerant. While all the isolates could tolerate pH from 2 to 14 (optimum 5-9), 7 isolates tolerated pH 1.5 as well. While all the fungal isolates tolerated salt concentration above 10 %; 10 isolates showed tolerance above 20 %. Based on ITS region (ITS1-5.8S-ITS2) analysis the fungal isolates belonged to 25 different species of Penicillium (showing similarity between 95 and 100 %). Characters like tolerance for low temperature, wide range of pH, and high salt concentration, and enhancement in sporulation and production of secondary metabolites such as watery exudates at low temperature can be attributed to the ecological resilience possessed by these fungi for survival under low temperature environment of mountain ecosystem.

  16. Photoresponse and H2 gas sensing properties of highly oriented Al and Al/Sb doped ZnO thin films

    Institute of Scientific and Technical Information of China (English)

    Hannane Benelmadjat; Boubekeur Boudine; Aissa Keffous; Noureddine Gabouze

    2013-01-01

    ZnO:Al and ZnO:Al/Sb thin films have been prepared and investigated. The thin films were deposited on Si substrates by the sol-gel method. The structural, optical and electrical properties of ZnO films have been investigated by spectrophotometry, ellipsometry, X-ray diffraction and current-voltage characterizations. It is found that the films exhibit wurtzite structure with a highly c-axis orientation perpendicular to the surface of the substrate, a high reflectivity in the infrared region and a response to illumination. Furthermore, it has been found that Si/(ZnO:Al/Sb)/Al photodiode is promising in photoconduction device while Si/(ZnO:Al)/Al can be used as gas sensor responding to the low H2 concentrations.

  17. High-pressure synthesis and superconductivity of the Laves phase compound Ca(Al,Si)2 composed of truncated tetrahedral cages Ca@(Al,Si))12.

    Science.gov (United States)

    Tanaka, Masashi; Zhang, Shuai; Inumaru, Kei; Yamanaka, Shoji

    2013-05-20

    The Zintl compound CaAl2Si2 peritectically decomposes to a new ternary cubic Laves phase Ca(Al,Si)2 and an Al-Si eutectic at temperatures above 750 °C under a pressure of 13 GPa. The ternary Laves phase compound can also be prepared as solid solutions Ca(Al(1-x)Si(x))2 (0.35 ≤ x ≤ 0.75) directly from the ternary mixtures under high-pressure and high-temperature conditions. The cubic Laves phase structure can be regarded as a type of clathrate compound composed of face-sharing truncated tetrahedral cages with Ca atoms at the center, Ca@(Al,Si)12. The compound with a stoichiometric composition CaAlSi exhibits superconductivity with a transition temperature of 2.6 K. This is the first superconducting Laves phase compound composed solely of commonly found elements.

  18. Microstructure and corrosion resistance of AlCrFeCuCo high entropy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xing-Wu, E-mail: qiuxingwu@126.com [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Department of Materials Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China); Zhang, Yun-Peng; He, Li [School of Material Science and Engineering, Xi' an University of Technology, Xi' an 710048 (China); Liu, Chun-ge [Department of Transportation and Municipal Engineering, Sichuan College of Architectural Technology, Deyang 618000 (China)

    2013-02-05

    Highlights: Black-Right-Pointing-Pointer We use a new method (laser cladding) to prepare high-entropy alloy. Black-Right-Pointing-Pointer We gained small microstructure under rapid solidification condition. Black-Right-Pointing-Pointer We studied corrosion resistance of AlCrFeCuCo high-entropy alloy in two different liquids. - Abstract: The AlCrFeCuCo high-entropy alloys were prepared by the laser cladding method. The microstructure and corrosion resistance property of AlCrFeCuCo high-entropy alloy were researched by scanning electron microscopy, X-ray diffraction and electrochemical workstation. The results show that, under the rapid solidification small microstructure gained, the morphology of AlCrFeCuCo high entropy alloy is simple, the phase mainly compose of FCC and BCC; elements segregated in the alloys; the alloy shows excellent corrosion resistance, along with the increase of the scanning speed, alloy corrosion resistance performance shows a enhancement in the first and then weakened trend. The corrosion resistance performance of AlCrFeCuCo high-entropy alloys in 1 mol/L NaCl solution is better than in 0.5 mol/L H{sub 2}SO{sub 4} solution.

  19. Physiological and proteomic changes suggest an important role of cell walls in the high tolerance to metals of Elodea nuttallii.

    Science.gov (United States)

    Larras, Floriane; Regier, Nicole; Planchon, Sébastien; Poté, John; Renaut, Jenny; Cosio, Claudia

    2013-12-15

    Macrophytes bioaccumulate metals, the suggestion being made that they be considered for phytoremediation. However, a thorough understanding of the mechanisms of metal tolerance in these plants is necessary to allow full optimization of this approach. The present study was undertaken to gain insight into Hg and Cd accumulation and their effects in a representative macrophyte, Elodea nuttallii. Exposure to methyl-Hg (23 ng dm(-3)) had no significant effect while inorganic Hg (70 ng dm(-3)) and Cd (281 μg dm(-3)) affected root growth but did not affect shoots growth, photosynthesis, or antioxidant enzymes. Phytochelatins were confirmed as having a role in Cd tolerance in this plant while Hg tolerance seems to rely on different mechanisms. Histology and subcellular distribution revealed a localized increase in lignification, and an increased proportion of metal accumulation in cell wall over time. Proteomics further suggested that E. nuttallii was able to efficiently adapt its energy sources and the structure of its cells during Hg and Cd exposure. Storage in cell walls to protect cellular machinery is certainly predominant at environmental concentrations of metals in this plant resulting in a high tolerance highlighted by the absence of toxicity symptoms in shoots despite the significant accumulation of metals.

  20. High-efficiency of AlInGaN/Al(In)GaN-delta AlGaN quantum wells for deep-ultraviolet emission

    Science.gov (United States)

    Saidi, Hosni; Ridene, Said

    2016-10-01

    Band structure and optical gain properties of AlInGaN/AlInGaN-delta-AlGaN quantum wells for deep-ultraviolet light emitting and lasers diodes with wavelength λ ∼229 nm and TE-polarized optical gain peak intensity ∼1.7 times larger than the conventional AlInN-delta-GaN was proposed and investigated in this work. The active region is made up of 20 Å staggered Al0.89In0.03Ga0.08N/Al0.8In 0.01Ga0.19N layers with a 3 Å Al0.46Ga0.54N delta layer. The use of the quaternary AlInGaN well layer permits the independent control of the band gap and the lattice parameter, so that the internal electric field induced by polarizations can be reduced and interband transition energy increases. Therefore, we can predict that the optical performance of the AlInGaN-delta-AlGaN is more convenient for an emission in the deep-ultraviolet than that of the conventional AlInN-delta-GaN-based quantum wells.

  1. Large magnetization and high Curie temperature in highly disordered nanoscale Fe2CrAl thin films

    Science.gov (United States)

    Dulal, Rajendra P.; Dahal, Bishnu R.; Forbes, Andrew; Pegg, Ian L.; Philip, John

    2017-02-01

    We have successfully grown nanoscale Fe2CrAl thin films on polished Si/SiO2 substrates using an ultra-high vacuum deposition with a base pressure of 9×10-10 Torr. The thickness of thin films ranges from 30 to 100 nm. These films exhibit cubic crystal structure with lattice disorder and display ferromagnetic behavior. The Curie temperature is greater than 400 K, which is much higher than that reported for bulk Fe2CrAl. The magnetic moments of the films varies from 2.5 to 2.8 μB per formula unit, which is larger than the reported bulk values. Thus, the disordered nanoscale Fe2CrAl films exhibit strong Fe-Fe exchange interactions through Fe-Cr-Fe and Fe-Al-Fe layers, resulting in both a large magnetization and a high Curie temperature.

  2. AlGaAs/GaAs photovoltaic converters for high power narrowband radiation

    Energy Technology Data Exchange (ETDEWEB)

    Khvostikov, Vladimir; Kalyuzhnyy, Nikolay; Mintairov, Sergey; Potapovich, Nataliia; Shvarts, Maxim; Sorokina, Svetlana; Andreev, Viacheslav [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021 (Russian Federation); Luque, Antonio [Ioffe Physical-Technical Institute, 26 Polytechnicheskaya, St. Petersburg, 194021, Russia and Instituto de Energia Solar, Universidad Politecnica de Madrid, Madrid (Spain)

    2014-09-26

    AlGaAs/GaAs-based laser power PV converters intended for operation with high-power (up to 100 W/cm{sup 2}) radiation were fabricated by LPE and MOCVD techniques. Monochromatic (λ = 809 nm) conversion efficiency up to 60% was measured at cells with back surface field and low (x = 0.2) Al concentration 'window'. Modules with a voltage of 4 V and the efficiency of 56% were designed and fabricated.

  3. Tolerance of spermatogonia to oxidative stress is due to high levels of Zn and Cu/Zn superoxide dismutase.

    Directory of Open Access Journals (Sweden)

    Fritzie T Celino

    Full Text Available BACKGROUND: Spermatogonia are highly tolerant to reactive oxygen species (ROS attack while advanced-stage germ cells such as spermatozoa are much more susceptible, but the precise reason for this variation in ROS tolerance remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using the Japanese eel testicular culture system that enables a complete spermatogenesis in vitro, we report that advanced-stage germ cells undergo intense apoptosis and exhibit strong signal for 8-hydroxy-2'-deoxyguanosine, an oxidative DNA damage marker, upon exposure to hypoxanthine-generated ROS while spermatogonia remain unaltered. Activity assay of antioxidant enzyme, superoxide dismutase (SOD and Western blot analysis using an anti-Copper/Zinc (Cu/Zn SOD antibody showed a high SOD activity and Cu/Zn SOD protein concentration during early spermatogenesis. Immunohistochemistry showed a strong expression for Cu/Zn SOD in spermatogonia but weak expression in advanced-stage germ cells. Zn deficiency reduced activity of the recombinant eel Cu/Zn SOD protein. Cu/Zn SOD siRNA decreased Cu/Zn SOD expression in spermatogonia and led to increased oxidative damage. CONCLUSIONS/SIGNIFICANCE: These data indicate that the presence of high levels of Cu/Zn SOD and Zn render spermatogonia resistant to ROS, and consequently protected from oxidative stress. These findings provide the biochemical basis for the high tolerance of spermatogonia to oxidative stress.

  4. Study on Damage of High Temperature Plastic Deformation for Al-Li Alloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The security of use for Al-Li alloy will be greatly influenced by the damage degree of plastic deformation within it at high temperature . Based on continuum damage mechanics theory, the damage evolution of Al-5.44Mg-2.15Li-0.12Zr alloy during plastic deforming at high temperature is simulated by using the damage evolution model of high temperature plastic deformation. The changing rule of its inner damage with deformation temperature, strain rate and strain is gained in this paper. The equation of damage evolution for high temperature plastic deformation is developed, providing an academic basis for the technology of plastic process of Al-Li alloys.

  5. Cordyceps militaris Improves Tolerance to High-Intensity Exercise After Acute and Chronic Supplementation.

    Science.gov (United States)

    Hirsch, Katie R; Smith-Ryan, Abbie E; Roelofs, Erica J; Trexler, Eric T; Mock, Meredith G

    2016-07-13

    To determine the effects of a mushroom blend containing Cordyceps militaris on high-intensity exercise after 1 and 3 weeks of supplementation. Twenty-eight individuals (Mean ± standard deviation [SD]; Age = 22.7 ± 4.1 yrs; Height = 175.4 ± 8.7 cm; Weight = 71.6 ± 12.0 kg) participated in this randomized, repeated measures, double-blind, placebo-controlled design. Maximal oxygen consumption (VO2max), time to exhaustion (TTE), and ventilatory threshold (VT) were measured during a maximal graded exercise test on a cycle ergometer. Relative peak power output (RPP), average power output (AvgP), and percent drop (%drop) were recorded during a 3 minute maximal cycle test with resistance at 4.5% body weight. Subjects consumed 4 g·d(-1) mushroom blend (MR) or maltodextrin (PL) for 1 week. Ten volunteers supplemented for an additional 2 weeks. Exercise tests were separated by at least 48 hours and repeated following supplementation periods. One week of supplementation elicited no significant time × treatment interaction for VO2max (p = 0.364), VT (p = 0.514), TTE (p = 0.540), RPP (p = 0.134), AvgP (p = 0.398), or %drop (p = 0.823). After 3 weeks, VO2max significantly improved (p = 0.042) in MR (+4.8 ml·kg(-1)·min(-1)), but not PL (+0.9 ml·kg(-1)·min(-1)). Analysis of 95% confidence intervals revealed significant improvements in TTE after 1- (+28.1 s) and 3 weeks (+69.8 s) in MR, but not PL, with additional improvements in VO2max (+4.8 ml·kg(-1)·min(-1)) and VT (+0.7 l·min(-1)) after 3 weeks. Acute supplementation with a Cordyceps militaris containing mushroom blend may improve tolerance to high-intensity exercise; greater benefits may be elicited with consistent chronic supplementation.

  6. Semi-High Throughput Screening for Potential Drought-tolerance in Lettuce (Lactuca sativa) Germplasm Collections.

    Science.gov (United States)

    Knepper, Caleb; Mou, Beiquan

    2015-04-17

    This protocol describes a method by which a large collection of the leafy green vegetable lettuce (Lactuca sativa L.) germplasm was screened for likely drought-tolerance traits. Fresh water availability for agricultural use is a growing concern across the United States as well as many regions of the world. Short-term drought events along with regulatory intervention in the regulation of water availability coupled with the looming threat of long-term climate shifts that may lead to reduced precipitation in many important agricultural regions has increased the need to hasten the development of crops adapted for improved water use efficiency in order to maintain or expand production in the coming years. This protocol is not meant as a step-by-step guide to identifying at either the physiological or molecular level drought-tolerance traits in lettuce, but rather is a method developed and refined through the screening of thousands of different lettuce varieties. The nature of this screen is based in part on the streamlined measurements focusing on only three water-stress indicators: leaf relative water content, wilt, and differential plant growth following drought-stress. The purpose of rapidly screening a large germplasm collection is to narrow the candidate pool to a point in which more intensive physiological, molecular, and genetic methods can be applied to identify specific drought-tolerant traits in either the lab or field. Candidates can also be directly incorporated into breeding programs as a source of drought-tolerance traits.

  7. Marine megaherbivore grazing may increase seagrass tolerance to high nutrient loads

    NARCIS (Netherlands)

    Christianen, M.J.A.; Govers, L.L.; Bouma, T.J.; Kiswara, Wawan; Roelofs, J.G.M.; Lamers, L.P.M.; van Katwijk, M.M.

    2012-01-01

    1. Populations of marine megaherbivores including green turtle (Chelonia mydas) have declined dramatically at a global scale as a result of overharvesting and habitat loss. This decline can be expected to also affect the tolerance of seagrass systems to coastal eutrophication. Until now, however, si

  8. Marine megaherbivore grazing may increase seagrass tolerance to high nutrient loads

    NARCIS (Netherlands)

    Christianen, M.J.A.; Govers, L.L.; Bouma, T.J.; Kiswara, W.; Roelofs, J.G.M.; Lamers, L.P.M.; Van Katwijk, M.

    2012-01-01

    1.Populations of marine megaherbivores including green turtle (Chelonia mydas) have declined dramatically at a global scale as a result of overharvesting and habitat loss. This decline can be expected to also affect the tolerance of seagrass systems to coastal eutrophication. Until now, however, sim

  9. Experimental evolution reveals high insecticide tolerance in Daphnia inhabiting farmland ponds

    NARCIS (Netherlands)

    Jansen, M.; Coors, A.; Vanoverbeke, J.; Schepens, M.; de Voogt, P.; De Schampelaere, K.A.C.; De Meester, L.

    2015-01-01

    Exposure of nontarget populations to agricultural chemicals is an important aspect of global change. We quantified the capacity of natural Daphnia magna populations to locally adapt to insecticide exposure through a selection experiment involving carbaryl exposure and a control. Carbaryl tolerance

  10. Marine megaherbivore grazing may increase seagrass tolerance to high nutrient loads

    NARCIS (Netherlands)

    Christianen, M.J.A.; Govers, L.L.; Bouma, T.J.; Kiswara, Wawan; Roelofs, J.G.M.; Lamers, L.P.M.; van Katwijk, M.M.

    2012-01-01

    1. Populations of marine megaherbivores including green turtle (Chelonia mydas) have declined dramatically at a global scale as a result of overharvesting and habitat loss. This decline can be expected to also affect the tolerance of seagrass systems to coastal eutrophication. Until now, however, si

  11. Marine megaherbivore grazing may increase seagrass tolerance to high nutrient loads

    NARCIS (Netherlands)

    Christianen, M.J.A.; Govers, L.L.; Bouma, T.J.; Kiswara, W.; Roelofs, J.G.M.; Lamers, L.P.M.; Van Katwijk, M.

    2012-01-01

    1.Populations of marine megaherbivores including green turtle (Chelonia mydas) have declined dramatically at a global scale as a result of overharvesting and habitat loss. This decline can be expected to also affect the tolerance of seagrass systems to coastal eutrophication. Until now, however, sim

  12. Demonstration of InAlN/AlGaN high electron mobility transistors with an enhanced breakdown voltage by pulsed metal organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xue, JunShuai, E-mail: junshuaixue@hotmail.com; Zhang, JinCheng; Hao, Yue [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China)

    2016-01-04

    In this work, InAlN/AlGaN heterostructures employing wider bandgap AlGaN instead of conventional GaN channel were grown on sapphire substrate by pulsed metal organic chemical vapor deposition, where the nominal Al composition in InAlN barrier and AlGaN channel were chosen to be 83% and 5%, respectively, to achieve close lattice-matched condition. An electron mobility of 511 cm{sup 2}/V s along with a sheet carrier density of 1.88 × 10{sup 13 }cm{sup −2} were revealed in the prepared heterostructures, both of which were lower compared with lattice-matched InAlN/GaN due to increased intrinsic alloy disorder scattering resulting from AlGaN channel and compressively piezoelectric polarization in barrier, respectively. While the high electron mobility transistor (HEMT) processed on these structures not only exhibited a sufficiently high drain output current density of 854 mA/mm but also demonstrated a significantly enhanced breakdown voltage of 87 V, which is twice higher than that of reported InAlN/GaN HEMT with the same device dimension, potential characteristics for high-voltage operation of GaN-based electronic devices.

  13. Demonstration of InAlN/AlGaN high electron mobility transistors with an enhanced breakdown voltage by pulsed metal organic chemical vapor deposition

    Science.gov (United States)

    Xue, JunShuai; Zhang, JinCheng; Hao, Yue

    2016-01-01

    In this work, InAlN/AlGaN heterostructures employing wider bandgap AlGaN instead of conventional GaN channel were grown on sapphire substrate by pulsed metal organic chemical vapor deposition, where the nominal Al composition in InAlN barrier and AlGaN channel were chosen to be 83% and 5%, respectively, to achieve close lattice-matched condition. An electron mobility of 511 cm2/V s along with a sheet carrier density of 1.88 × 1013 cm-2 were revealed in the prepared heterostructures, both of which were lower compared with lattice-matched InAlN/GaN due to increased intrinsic alloy disorder scattering resulting from AlGaN channel and compressively piezoelectric polarization in barrier, respectively. While the high electron mobility transistor (HEMT) processed on these structures not only exhibited a sufficiently high drain output current density of 854 mA/mm but also demonstrated a significantly enhanced breakdown voltage of 87 V, which is twice higher than that of reported InAlN/GaN HEMT with the same device dimension, potential characteristics for high-voltage operation of GaN-based electronic devices.

  14. Fault Diagnosis and Fault-Tolerant Control of Uncertain Robot Manipulators Using High-Order Sliding Mode

    Directory of Open Access Journals (Sweden)

    Mien Van

    2016-01-01

    Full Text Available A robust fault diagnosis and fault-tolerant control (FTC system for uncertain robot manipulators without joint velocity measurement is presented. The actuator faults and robot manipulator component faults are considered. The proposed scheme is designed via an active fault-tolerant control strategy by combining a fault diagnosis scheme based on a super-twisting third-order sliding mode (STW-TOSM observer with a robust super-twisting second-order sliding mode (STW-SOSM controller. Compared to the existing FTC methods, the proposed FTC method can accommodate not only faults but also uncertainties, and it does not require a velocity measurement. In addition, because the proposed scheme is designed based on the high-order sliding mode (HOSM observer/controller strategy, it exhibits fast convergence, high accuracy, and less chattering. Finally, computer simulation results for a PUMA560 robot are obtained to verify the effectiveness of the proposed strategy.

  15. Physical activity of relatively high intensity in mid-pregnancy predicts lower glucose tolerance levels.

    Science.gov (United States)

    Medek, Helga; Halldorsson, Thorhallur; Gunnarsdottir, Ingibjörg; Geirsson, Reynir T

    2016-09-01

    Physical activity (PA) is recommended as part of therapy for patients with impaired glucose tolerance. Whether such recommendations are also justified for pregnant women is less well established. We investigated the association between PA and glucose tolerance in pregnancy. A non-selective sample of 217 pregnant women was recruited at a routine 20 week ultrasound examination. Participants answered the International Physical Activity Questionnaire (IPAQ) about frequency, intensity and duration of daily physical activity in the past 7 days and underwent oral glucose tolerance testing (OGTT) between 24 and 28 weeks. A subset of 72 overweight/obese pregnant women wore a pedometer for 1 week with assessment of IPAQ score and pedometric correlations to this. Of the sample, 177 attended for OGTT; 51% were overweight or obese. The mean (SD) fasting glucose was 4.5 (0.4) mmol/L, and 12% had gestational diabetes mellitus. Only one-third engaged in vigorous PA. After adjustment for pre-pregnancy BMI, age and parity, those engaging in vigorous PA had significantly lower fasting glucose levels (by 0.15 mmol/L, 95% CI 0.03-0.27) compared with those not vigorously active. This decrease was similar in both normal and overweight/obese women. There were fewer cases of gestational diabetes (p = 0.03) among the vigorously active women (3/56; 5%) than among those who were not active (19/121; 16%). No association with glucose tolerance was observed for physical activity of moderate intensity. Only vigorous physical activity appears beneficial with respect to maternal glucose tolerance, both among normal, overweight and obese women. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

  16. Synthesis of highly porous Al2O3-YAG composite ceramics

    Directory of Open Access Journals (Sweden)

    Egelja Adela

    2016-01-01

    Full Text Available Al2O3-YAG composite was obtained by sintering of porous Al2O3 preforms infiltrated with water solution of aluminium nitrate nonahydrate, Al(NO33•9H2O and yttrium nitrate hexahydrate, Y(NO33•6H2O. Al2O3 preforms with porosity varying from 26 to 50% were obtained after sintering at temperature ranging from 1100 to 1500°C. Sintering of the infiltrated Al2O3 preforms led to formation of YAG particles due to reaction between Y2O3 and Al2O3 at high temperature. It was found that variation of porosity of alumina preforms and sintering temperature is an effective way to fabricate Al2O3-YAG composite with an unusual combination of properties. Open porosity was in the range 15-35%, specific surface was 0.6-6.1 m2/g, pore size was 150-900 nm whereas compressive strength was from 50 to 250 MPa. The effect of sintering temperature on YAG formation and phase composition were investigated using X-ray diffractometry whereas microstructure of the composite was analysed by scanning electron microscopy. [Projekat Ministartsva nauke Republike Srbije, br. 45012

  17. High-performance Ni[sub 3]Al synthesized from composite powders

    Energy Technology Data Exchange (ETDEWEB)

    Chiou, W.C.; Hu, C.T. (National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Materials Science and Engineering)

    1994-05-01

    Specimens of Ni[sub 3]Al + B of high density (>99.3 pct RD) and relatively large dimension have been synthesized from composite powders through processes of replacing plating and electroless Ni-B plating on Al powder, sintering, and thermal-mechanical treatment. The uniformly coated Ni layer over fine Al or Ni core particles constituting these coating/core composite powders has advantages such as better resistance to oxidation relative to pure Al powder, a greater green density as a compacted powder than prealloyed powder, the possibility of atomically added B to the material by careful choice of a suitable plating solution, and avoidance of the expensive powder metallurgy (PM) equipment such as a hot isostatic press (HIP), hot press (HP), etc. The final Ni[sub 3]Al + B product is made from Ni-B-Al and Ni-B-Ni mixed composite powders by means of traditional PM processes such as compacting, sintering, rolling, and annealing, and therefore, the dimensions of the product are not constrained by the capacity of an HIP or HP. The properties of Ni[sub 3]Al composite powder metallurgy (CPM) specimens tested at room temperature have been obtained, and comparison with previous reports is conducted. A tensile elongation of about 16 pct at room temperature was attained.

  18. High salinity tolerance of the Red Sea coral Fungia granulosa under desalination concentrate discharge conditions: an in situ photophysiology experiment

    KAUST Repository

    Van Der Merwe, Riaan

    2014-11-10

    Seawater reverse osmosis desalination concentrate may have chronic and/or acute impacts on the marine ecosystems in the near-field area of the discharge. Environmental impact of the desalination plant discharge is supposedly site- and volumetric- specific, and also depends on the salinity tolerance of the organisms inhabiting the water column in and around a discharge environment. Scientific studies that aim to understand possible impacts of elevated salinity levels are important to assess detrimental effects to organisms, especially for species with no mechanism of osmoregulation, e.g., presumably corals. Previous studies on corals indicate sensitivity toward hypo- and hyper-saline environments with small changes in salinity already affecting coral physiology. In order to evaluate sensitivity of Red Sea corals to increased salinity levels, we conducted a long-term (29 days) in situ salinity tolerance transect study at an offshore seawater reverse osmosis (SWRO) discharge on the coral Fungia granulosa. While we measured a pronounced increase in salinity and temperature at the direct outlet of the discharge structure, effects were indistinguishable from the surrounding environment at a distance of 5 m. Interestingly, corals were not affected by varying salinity levels as indicated by measurements of the photosynthetic efficiency. Similarly, cultured coral symbionts of the genus Symbiodinium displayed remarkable tolerance levels in regard to hypo- and hypersaline treatments. Our data suggest that increased salinity and temperature levels from discharge outlets wear off quickly in the surrounding environment. Furthermore, F. granulosa seem to tolerate levels of salinity that are distinctively higher than reported for other corals previously. It remains to be determined whether Red Sea corals in general display increased salinity tolerance, and whether this is related to prevailing levels of high(er) salinity in the Red Sea in comparison to other oceans.

  19. 高纯α-AlH3的合成及表征%Synthesis and Characterization of α-AlH3 with High Purity

    Institute of Scientific and Technical Information of China (English)

    张永岗; 开永茂; 汪伟; 邱少君; 李鸿波

    2012-01-01

    为制备高纯α-AlH3,将LiAlH4与AlCl3在乙醚溶液中反应,制备并分离出固体AlH3乙醚络合物,其在甲苯中90℃下脱醚2h可制得纯度为99.5%的α-AlH3,产率96.4%.对高纯α-AlH3进行了XRD、红外、元素分析、TG/DSC、SEM表征,同时考察了α-AlH3的结晶条件和稳定性.结果表明产品结晶性好、纯度高、性质稳定,合成方法具有操作简便、收率高、重现性好等优点.%In order to obtain α-AlH3 with high purity, solid AlH3-etherate was synthesized and separated from the reaction of LiAlH4 and A1C13 in diethyl ether, then α-A1H3 with purity of 99. 5 % was prepared via desolvation of the solid AlH3-etherate in toluene at 90℃ for 2 hours in the yield of 96. 4%. The product was characterized by XRD, IR, elemental analysis, TG/DSC, SEM, meanwhile the crystallization and stability of α-AlH3 was also studied. The results indicate that the product has good crystallization, high purity and stability, the synthetic method has the advantages of simple operation, high yield and good reproducibility.

  20. Preparation of highly oriented Al:ZnO and Cu/Al:ZnO thin films by sol-gel method and their characterization

    Energy Technology Data Exchange (ETDEWEB)

    Vijayaprasath, G.; Murugan, R. [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of); Hayakawa, Y. [Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8011 (Japan); Ravi, G., E-mail: gravicrc@gmail.com [School of Physics, Alagappa University, Karaikudi 630 004, Tamil Nadu (India)

    2015-11-15

    Highly oriented thin films of Al doped ZnO (Al:ZnO) and Cu co-doped Al:ZnO (Cu/Al:ZnO) thin films were successfully deposited by sol–gel spin coating on glass substrates. The deposited films were characterized using X-ray diffraction analysis and found to exhibit hexagonal wurtzite structure with c-axis orientation. SEM images revealed that hexagonal rod shaped morphologies were grown perpendicular to the substrate surface due to repeated deposition process. High transmittance values were observed for pure ZnO compared to Al:ZnO and Cu/Al:ZnO thin films. The band gap widening is caused by the increase of carrier concentration, which is believed to be due to Burstein-Moss effect due to Al and Cu doping. PL spectra of Cu/Al:ZnO thin films indicate that the UV emission peaks slightly shifted towards lower energy side. XPS study was carried out for Zn{sub 0.80}Al{sub 0.10}Cu{sub 0.10}O thin films to analyze the binding energy of Al, Cu, Zn and O. Magnetic measurement studies exhibited ferromagnetic behavior at room temperature, which may be due to the increase in copper concentration in the doped films. The ferromagnetic behavior can be understood from the exchange coupling between localized ‘d’ spin of Cu ion mediated by free delocalized carriers. - Highlights: • High quality of Al:ZnO and Cu co-doped Al:ZnO thin films were fabricated by sol–gel method. • The XRD analyses revealed that the deposited thin films have hexagonal wurtzite structure. • XPS was carried out for Zn{sub 0.80}Al{sub 0.10}Cu{sub 0.10}O films to analyze the binding energy of Al, Cu, Zn and O. • SEM studies were made for Al:ZnO and Cu/Al:ZnO thin films. • RTFM was observed in Cu co-doped Al:ZnO thin films.

  1. TEM and HRTEM study of oxide particles in an Al-alloyed high-Cr oxide dispersion strengthened ferritic steel with Hf addition

    Science.gov (United States)

    Dou, Peng; Kimura, Akihiko; Kasada, Ryuta; Okuda, Takanari; Inoue, Masaki; Ukai, Shigeharu; Ohnuki, Somei; Fujisawa, Toshiharu; Abe, Fujio; Jiang, Shan; Yang, Zhigang

    2017-03-01

    The nanoparticles in an Al-alloyed high-Cr oxide dispersion strengthened (ODS) ferritic steel with Hf addition, i.e., SOC-16 (Fe-15Cr-2W-0.1Ti-4Al-0.62Hf-0.35Y2O3), have been examined by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). Relative to an Al-alloyed high-Cr ODS ferritic steel without Hf addition, i.e., SOC-9 (Fe-15.5Cr-2W-0.1Ti-4Al-0.35Y2O3), the dispersion morphology and coherency of the oxide nanoparticles in SOC-16 were significantly improved. Almost all the small nanoparticles (diameter anion-deficient fluorite structure and coherent with the bcc steel matrix. The larger particles (diameter >10 nm) were also mainly identified as cubic Y2Hf2O7 oxides with the anion-deficient fluorite structure. The results presented here are compared with those of SOC-9 with a brief discussion of the underlying mechanisms of the unusual thermal and irradiation stabilities of the oxides as well as the superior strength, excellent irradiation tolerance and extraordinary corrosion resistance of SOC-16.

  2. Focus on CSIR research in pollution and waste: High sulphide Concentrations tolerated by sulphate reducing bacteria

    CSIR Research Space (South Africa)

    Greben, H

    2007-08-01

    Full Text Available (SRB) and organic matter such as ethanol. During this process hydrogen sulphide (H2S) is formed, which can have toxic effects on the methanogenic activity (Koster et al.,1986) as well as on the sulphidogenic bacteria (Okabe et al., 1995). Lens...

  3. Trap states in AlGaN channel high-electron-mobility transistors

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, ShengLei; Zhang, Kai; Ha, Wei; Chen, YongHe; Zhang, Peng; Zhang, JinCheng; Hao, Yue, E-mail: yhao@xidian.edu.cn [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China); Ma, XiaoHua, E-mail: xhma@xidian.edu.cn [Key Laboratory of Wide Band Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University, Xi' an 710071 (China); School of Advanced Materials and Nanotechnology, Xidian University, Xi' an 710071 (China)

    2013-11-18

    Frequency dependent capacitance and conductance measurements were performed to analyze the trap states in the AlGaN channel high-electron-mobility transistors (HEMTs). The trap state density in the AlGaN channel HEMTs decreases from 1.26 × 10{sup 13} cm{sup −2}eV{sup −1} at the energy of 0.33 eV to 4.35 × 10{sup 11} cm{sup −2}eV{sup −1} at 0.40 eV. Compared with GaN channel HEMTs, the trap states in the AlGaN channel HEMTs have deeper energy levels. The trap with deeper energy levels in the AlGaN channel HEMTs is another reason for the reduction of the reverse gate leakage current besides the higher Schottky barrier height.

  4. Laser remelting of Ti6AL4V using high power diode laser

    Science.gov (United States)

    Amaya-Vázquez, M. R.; Sánchez-Amaya, J. M.; Boukha, Z.; El Amrani, K.; Botana, F. J.

    2012-04-01

    Titanium alloys present excellent mechanical and corrosion properties, being widely employed in different industries such as medical, aerospace, automotive, petrochemical, nuclear and power generation, etc. Ti6Al4V is the α-β alloy most employed in industry. The modification of its properties can be achieved with convectional heat treatments and/or with laser processing. Laser remelting (LR) is a technology applied to Ti6Al4V by other authors with excimer and Nd-Yag laser with pure argon shielding gas to prevent risk of oxidation. In the present contribution, laser remelting has been applied for the first time to Ti6Al4V with a high power diode laser (with pure argon as shielding gas). Results showed that remelted samples (with medium energy densities) have higher microhardness and better corrosion resistance than Ti6Al4V base metal.

  5. Influence of Al-W-B Recycled Composite Material on the Properties of High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Baronins Janis

    2015-12-01

    Full Text Available The aim of this study is to obtain high performance boron containing material with sufficient carrying capacity with increased porosity and lower density at the same time. The influence of the different concentrations of Al-W-B powder on the properties of the fresh and hardened HPC was investigated. In the concrete mix design, the allite containing White Portland cement CEM I 52,5 R, granite stone, sand, microsilica, on polycarboxylates based super plasticizer and Al-W-B powder were used. As a source of boron composite material (CM, previously grinded powder containing boron-tungsten fiber and aluminium matrix (CM Al-W-B was used. Grinding was used for processing of CM Al-W-B powder.

  6. Influence of Al and Cu elements on the microstructure and properties of (FeCrNiCo)Al{sub x}Cu{sub y} high-entropy alloys

    Energy Technology Data Exchange (ETDEWEB)

    Fan, Q.C., E-mail: fanqichao@126.com [Institute of Machinery Manufacturing Technology, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China); Li, B.S. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Zhang, Y. [Institute of Machinery Manufacturing Technology, Chinese Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

    2014-11-25

    Highlights: • Relationship between entropy and enthalpy on phase formation was specified. • Phase changed from fcc to fcc plus bcc and then bcc phase. • Mechanical properties changed from plasticity to brittleness. • Young’s modulus, hardness and yield strength increased with Al element. - Abstract: (FeCrNiCo)Al{sub x}Cu{sub y} high-entropy alloys were designed using the strategy of equiatomic ratio, high entropy of mixing and different mixing enthalpies of atom-pairs. The effects of entropy and enthalpy on phase forming process of the alloys were clearly studied and the influences of Al and Cu elements on the microstructure and mechanical properties were investigated. As long as Al element level increased from 0.5 to 1, the microstructure of the alloy system changed from fcc structure to duplex fcc plus bcc structure and then a single bcc structure. Increase of Al element greatly enhanced the Young’s modulus, hardness and yield strength of these alloys. (FeCrNiCo)Al{sub 0.75}Cu{sub 0.5} alloy got the most excellent comprehensive mechanical properties; its fracture strength and plastic strain were as high as 2270 MPa, and 42.70%, respectively. Cu-rich phase formed in the alloys when Cu element was in high levels. Increase of Cu element greatly decreased fracture strength of the high-entropy alloys when Al element was in the high level of x = 1.

  7. Compact analytical model for single gate AlInSb/InSb high electron mobility transistors

    Institute of Scientific and Technical Information of China (English)

    S.Theodore Chandra; N.B.Balamurugan; G.Subalakshmi; T.Shalini; G.Lakshmi Priya

    2014-01-01

    We have developed a 2D analytical model for the single gate AlInSb/InSb HEMT device by solving the Poisson equation using the parabolic approximation method.The developed model analyses the device performance by calculating the parameters such as surface potential,electric field distribution and drain current.The high mobility of the AlInSb/InSb quantum makes this HEMT ideal for high frequency,high power applications.The working of the single gate AlInSb/InSb HEMT device is studied by considering the variation of gate source voltage,drain source voltage,and channel length under the gate region and temperature.The carrier transport efficiency is improved by uniform electric field along the channel and the peak values near the source and drain regions.The results from the analytical model are compared with that of numerical simulations (TCAD) and a good agreement between them is achieved.

  8. Changes in extreme high-temperature tolerance and activities of antioxidant enzymes of sacred lotus seeds.

    Science.gov (United States)

    Ding, YanFen; Cheng, HongYan; Song, SongQuan

    2008-09-01

    Sacred lotus (Nelumbo nucifera Gaertn. 'Tielian') seed is long-lived and extremely tolerant of high temperature. Water content of lotus and maize seeds was 0.103 and 0.129 g H2O [g DW](-1), respectively. Water content, germination percentage and fresh weight of seedlings produced by surviving seeds gradually decreased with increasing treatment time at 100 degrees C. Germination percentage of maize (Zea mays L. 'Huangbaogu') seeds was zero after they were treated at 100 degrees C for 15 min and that of lotus seeds was 13.5% following the treatment at 100 degrees C for 24 h. The time in which 50% of lotus and maize seeds were killed by 100 degrees C was about 14.5 h and 6 min, respectively. With increasing treatment time at 100 degrees C, relative electrolyte leakage of lotus axes increased significantly, and total chlorophyll content of lotus axes markedly decreased. When treatment time at 100 degrees C was less than 12 h, subcellular structure of lotus hypocotyls remained fully intact. When treatment time at 100 degrees C was more than 12 h, plasmolysis gradually occurred, endoplasmic reticulum became unclear, nuclei and nucleoli broke down, most of mitochondria swelled, lipid granules accumulated at the cell periphery, and organelles and plasmolemma collapsed. Malondialdehyde (MDA) content of lotus axes and cotyledons decreased during 0 -12 h of the treatment at 100 degrees C and then increased. By contrast, the MDA content of maize embryos and endosperms increased during 5-10 min of the treatment at 100 degrees C and then decreased slightly. For lotus seeds: (1) activities of superoxide dismutase (SOD) and glutathione reductase (GR) of axes and cotyledons and of catalase (CAT) of axes increased during the early phase of treatment at 100 degrees C and then decreased; and (2) activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) of axes and cotyledons and of CAT of cotyledons gradually decreased with increasing treatment time at 100 degrees

  9. Changes in extreme high-temperature tolerance and activities of antioxidant enzymes of sacred lotus seeds

    Institute of Scientific and Technical Information of China (English)

    DING YanFen; CHENG HongYan; SONG SongQuan

    2008-01-01

    Sacred lotus (Nelumbo nucifera Gaertn. 'Tielian') seed is long-lived and extremely tolerant of high temperature. Water content of lotus and maize seeds was 0.103 and 0.129 g H2O [g DW]-1, respectively. Water content, germination percentage and fresh weight of seedlings produced by surviving seeds gradually decreased with increasing treatment time at 100℃. Germination percentage of maize (Zea mays L. 'Huangbaogu') seeds was zero after they were treated at 100℃ for 15 min and that of lotus seeds was 13.5% following the treatment at 100℃ for 24 h. The time in which 50% of lotus and maize seeds were killed by 100℃ was about 14.5 h and 6 min, respectively. With increasing treatment time at 100℃, relative electrolyte leakage of lotus axes increased significantly, and total chlorophyll content of lotus axes markedly decreased. When treatment time at 100℃ was less than 12 h, subcellular structure of lotus hypocotyls remained fully intact. When treatment time at 100℃ was more than 12 h, plasmoly-sis gradually occurred, endoplasmic reticulum became unclear, nuclei and nucleoli broke down, most of mitochondria swelled, lipid granules accumulated at the cell periphery, and organelles and plas-molemma collapsed. Malondialdehyde (MDA) content of lotus axes and cotyledons decreased during 0 -12 h of the treatment at 100℃ and then increased. By contrast, the MDA content of maize embryos and endosperms increased during 5-10 min of the treatment at 100℃ and then decreased slightly. For lotus seeds: (1) activities of superoxide dismutase (SOD) and glutathione reductase (GR) of axes and cotyledons and of catalase (CAT) of axes increased during the early phase of treatment at 100℃ and then decreased; and (2) activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) of axes and cotyledons and of CAT of cotyledons gradually decreased with increasing treat-ment time at 100℃. For maize seeds: (1) activities of SOD and DHAR of embryos and

  10. Changes in extreme high-temperature tolerance and activities of antioxidant enzymes of sacred lotus seeds

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Sacred lotus (Nelumbo nucifera Gaertn. ‘Tielian’) seed is long-lived and extremely tolerant of high temperature. Water content of lotus and maize seeds was 0.103 and 0.129 g H2O [g DW] ?1, respectively. Water content, germination percentage and fresh weight of seedlings produced by surviving seeds gradually decreased with increasing treatment time at 100℃. Germination percentage of maize (Zea mays L. ‘Huangbaogu’) seeds was zero after they were treated at 100℃ for 15 min and that of lotus seeds was 13.5% following the treatment at 100℃ for 24 h. The time in which 50% of lotus and maize seeds were killed by 100℃ was about 14.5 h and 6 min, respectively. With increasing treatment time at 100℃, relative electrolyte leakage of lotus axes increased significantly, and total chlorophyll content of lotus axes markedly decreased. When treatment time at 100℃ was less than 12 h, subcellular structure of lotus hypocotyls remained fully intact. When treatment time at 100℃ was more than 12 h, plasmoly-sis gradually occurred, endoplasmic reticulum became unclear, nuclei and nucleoli broke down, most of mitochondria swelled, lipid granules accumulated at the cell periphery, and organelles and plas-molemma collapsed. Malondialdehyde (MDA) content of lotus axes and cotyledons decreased during 0-12 h of the treatment at 100℃ and then increased. By contrast, the MDA content of maize embryos and endosperms increased during 5-10 min of the treatment at 100℃ and then decreased slightly. For lotus seeds: (1) activities of superoxide dismutase (SOD) and glutathione reductase (GR) of axes and cotyledons and of catalase (CAT) of axes increased during the early phase of treatment at 100℃ and then decreased; and (2) activities of ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) of axes and cotyledons and of CAT of cotyledons gradually decreased with increasing treat-ment time at 100℃. For maize seeds: (1) activities of SOD and DHAR of embryos and

  11. Advantages of the AlGaN spacer in InAlN high-electron-mobility transistors grown using metalorganic vapor phase epitaxy

    Science.gov (United States)

    Yamada, Atsushi; Ishiguro, Tetsuro; Kotani, Junji; Tomabechi, Shuichi; Nakamura, Norikazu; Watanabe, Keiji

    2016-05-01

    We demonstrate the advantages of an AlGaN spacer layer in an InAlN high-electron-mobility transistor (HEMT). We investigated the effects of the growth parameters of the spacer layer on electron mobility in InAlN HEMTs grown by metalorganic vapor phase epitaxy, focusing on the surface roughness of the spacer layer and sharpness of the interface with the GaN channel layer. The electron mobility degraded, as evidenced by the formation of a graded AlGaN layer at the top of the GaN channel layer and the surface roughness of the AlN spacer layer. We believe that the short migration length of aluminum atoms is responsible for the observed degradation. An AlGaN spacer layer was employed to suppress the formation of the graded AlGaN layer and improve surface morphology. A high electron mobility of 1550 cm2 V-1 s-1 and a low sheet resistance of 211 Ω/sq were achieved for an InAlN HEMT with an AlGaN spacer layer.

  12. Glucose tolerance, lipids, and GLP-1 secretion in JCR:LA-cp rats fed a high protein fiber diet.

    Science.gov (United States)

    Reimer, Raylene A; Russell, James C

    2008-01-01

    We have shown that individually, dietary fiber and protein increase secretion of the anorexigenic and insulinotropic hormone, glucagon-like peptide-1 (GLP-1). Our objective was to combine, in one diet, high levels of fiber and protein to maximize GLP-1 secretion, improve glucose tolerance, and reduce weight gain. Lean (+/?) and obese (cp/cp) male James C Russell corpulent (JCR:LA-cp) rats lacking a functional leptin receptor were fed one of four experimental diets (control, high protein (HP), high fiber (HF, prebiotic fiber inulin), or combination (CB)) for 3 weeks. An oral glucose tolerance test (OGTT) was performed to evaluate plasma GLP-1, insulin and glucose. Plasma lipids and intestinal proglucagon mRNA expression were determined. Energy intake was lower with the HF diet in lean and obese rats. Weight gain did not differ between diets. Higher colonic proglucagon mRNA in lean rats fed a CB diet was associated with higher GLP-1 secretion during OGTT. The HP diet significantly reduced plasma glucose area under the curve (AUC) during OGTT in obese rats, which reflected both an increased GLP-1 AUC and higher fasting insulin. Diets containing inulin resulted in the lowest plasma triglyceride and total cholesterol levels. Overall, combining HP with HF in the diet increased GLP-1 secretion in response to oral glucose, but did not improve glucose tolerance or lipid profiles more than the HF diet alone did. We also suggest that glycemic and insulinemic response to prebiotics differ among rat models and future research work should examine their role in improving glucose tolerance in diet-induced vs. genetic obesity with overt hyperleptinemia.

  13. Improved electrical properties of the two-dimensional electron gas in AlGaN/GaN heterostructures using high temperature AlN interlayers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The electrical properties of two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures using high temperature (HT) AlN interlayers (ITs) grown on c-plane sapphire substrate by metal organic chemical vapor deposition (MOCVD) have been investigated.It is found that the electrical properties (electron mobility and sheet carrier density) are improved compared with those in the conventional AlGaN/GaN heterostructures without HT AlN ITs,and the improved 2DEG properties result in the reduction of the sheet resistance.The results from high resolution X-ray diffraction (HRXRD) and Raman spectroscopy measurements show that HT AlN ITs increase the in-plane compressive strain in the upper GaN layer,which enhances the piezoelectric polarization in it and consequently causes increasing of 2DEG density at the AlGaN/GaN interface.Meanwhile,the compressive strain induced by HT AlN ITs leads to a less tensile strain in AlGaN barrier layer and causes positive and negative effects on the sheet carrier density of 2DEG,which counteract each other.The HT AlN ITs reduce the lattice mismatch between the GaN and AlGaN layers and smooth the interface between them,thus increasing the electric mobility of 2DEG by weakening the alloy-related interface roughness and scattering.In addition,the surface morphology of AlGaN/GaN heterostructures is improved by the insertion of HT AlN ITs.The reason for the improved properties is discussed in this paper.

  14. Unraveling the Origin of Structural Disorder in High Temperature Transition Al2O3: Structure of θ-Al2O3

    Energy Technology Data Exchange (ETDEWEB)

    Kovarik, Libor; Bowden, Mark E.; Shi, Dachuan; Washton, Nancy M.; Anderson, Amity; Hu, Jian Z.; Lee, Jaekyoung; Szanyi, Janos; Kwak, Ja Hun; Peden, Charles HF

    2015-09-22

    The crystallography of transition Al2O3 has been extensively studied in the past due to the advantageous properties of the oxide in catalytic and a range of other technological applications. However, existing crystallographic models are insufficient to describe the structure of many important Al2O3 polymorphs due to their highly disordered nature. In this work, we investigate structure and disorder in high-temperature treated transition Al2O3, and provide a structural description for θ-Al2O3 by using a suite of complementary imaging, spectroscopy and quantum calculation techniques. Contrary to current understanding, our high-resolution imaging shows that θ-Al2O3 is a disordered composite phase of at least two different end members. By correlating imaging and spectroscopy results with DFT calculations, we propose a model that describes θ-Al2O3 as a disordered intergrowth of two crystallographic variants at the unit cell level. One variant is based on β-Ga2O3, and the other on a monoclinic phase that is closely-related to δ-Al2O3. The overall findings and interpretations afford new insight into the origin of poor crystallinity in transition Al2O3, and also provide new perspectives on structural complexity that can emerge from intergrowth of closely related structural polymorphs.

  15. InAlAs photovoltaic cell design for high device efficiency: InAlAs photovoltaic cell design for high device efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Brittany L. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623; Bittner, Zachary S. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623; Hellstroem, Staffan D. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623; Nelson, George T. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623; Slocum, Michael A. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623; Norman, Andrew G. [NREL, National Center for Photovoltaics, 15013 Denver West Parkway Golden CO USA; Forbes, David V. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623; Hubbard, Seth M. [Rochester Institute of Technology, NanoPower Research Laboratory, 168 Lomb Memorial Drive Rochester NY USA 14623

    2017-04-17

    This study presents a new design for a single-junction InAlAs solar cell, which reduces parasitic absorption losses from the low band-gap contact layer while maintaining a functional window layer by integrating a selective etch stop. The etch stop is then removed prior to depositing an anti-reflective coating. The final cell had a 17.9% efficiency under 1-sun AM1.5 with an anti-reflective coating. Minority carrier diffusion lengths were extracted from external quantum efficiency data using physics-based device simulation software yielding 170 nm in the n-type emitter and 4.6 um in the p-type base, which is more than four times the diffusion length previously reported for a p-type InAlAs base. This report represents significant progress towards a high-performance InAlAs top cell for a triple-junction design lattice-matched to InP.

  16. 454-sequencing reveals stochastic local reassembly and high disturbance tolerance within arbuscular mycorrhizal fungal communities

    DEFF Research Database (Denmark)

    Lekberg, Karin Ylva Margareta; Schnoor, Tim; Kjøller, Rasmus

    2012-01-01

    1. Disturbance is assumed to be a major driver of plant community composition, but whether similar processes operate on associated soil microbial communities is less known. Based on the assumed trade-off between disturbance tolerance and competiveness, we hypothesize that a severe disturbance......, disturbance did not significantly alter the community composition and OTU richness. Instead, OTU abundances were positively correlated across treatments; i.e., common OTUs in undisturbed soil were also common after the severe disturbance. However, the distribution of OTUs within and between plots was largely...... applied within a semi-natural grassland would shift the arbuscular mycorrhizal (AM) fungal community towards disturbance-tolerant fungi that are rare in undisturbed soils. 2. We used 454-sequencing of the large subunit rDNAregion to characterizeAMfungal communities in Plantago lanceolata roots grown...

  17. Kinetic analysis of high-concentration isopropanol biodegradation by a solvent-tolerant mixed microbial culture.

    Science.gov (United States)

    Bustard, Mark T; Meeyoo, Vissanu; Wright, Phillip C

    2002-06-20

    The ability of a previously enriched microbial population to utilize isopropanol (IPA) as the sole carbon source within a minimal salts medium is studied. The advantage of prior enrichment procedures for the improvement of IPA biodegradation performance is demonstrated for an IPA concentration of up to 24 g L(-1). Results showing the interrelationship between temperature and substrate utilization and inhibition levels at temperatures of between 2 degrees C and 45 degrees C are examined. Models of inhibition based on enzyme kinetics are assessed via nonlinear analysis, in order to accurately represent the growth kinetics of this solvent-tolerant mixed culture. The model that best describes the data is the Levenspiel substrate inhibition model, which can predict the maximum substrate level above which growth is completely limited. This is the first report of IPA treatment of up to 24 g L(-1) by an aerobic solvent-tolerant population.

  18. Preparation and investigation of nano-AlN lubricant with high performance

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Yu; Tao, Yuxiao; Wang, Biaobing [School of Materials Science and Engineering, Changzhou University, Changzhou 201326 (China); Tai, Yanlong, E-mail: ytai@ucdavis.edu [Department of Biomedical Engineering, University of California Davis, Davis, CA 95616 (United States)

    2014-09-15

    A new kind of macromolecular coupling agent (LMW-a-PP-g-MAH) of maleic anhydride (MAH) onto low-molecular-weight atactic polypropylene (LMW-a-PP) was synthesized according to molecular design and was used as modifier for surface modification of nano-Aluminum nitride (AlN) by a high-pressure homogenization (HPH) process. IR was conducted to confirm the chemical structure of the step products of LMW-a-PP-g-MAH. The availability as a modifier for surface modification of nano-AlN was distinguished by Fourier transform infrared spectroscopy (FTIR), particle size analysis, transmission electron microscope (TEM), thermogravimetric analysis (TGA), contact angle experiments and the dispersion stability in dimethylbenzene and Greatwall lubrication oil. It can be inferred that the optimal loading is 10 wt. %–12 wt. % of LMW-a-PP-g-MAH to modify nano-AlN particles. Nano-AlN lubricating composite materials (LMW-a-PP-g-MAH-AlN) was used to improve the antifriction performance and the load capability of Greatwall lubrication oil, and maximum non-seizure load (P{sub B}) can increase highly from 1000 N to 1490 N when the loading is 0.3 wt. %. - Highlights: • Design and synthesis of macromolecular coupling agent (a-PP-g-MAH). • Surface modification and characterization of nano-AlN by HPH process. • Preparation and investigation of nano-AlN/lubricating oil with high performance.

  19. Road Map for Development of Crystal-Tolerant High Level Waste Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Josef; Vienna, John D.; Peeler, David; Fox, Kevin; Herman, Connie; Kruger, Albert A.

    2014-05-31

    This road map guides the research and development for formulation and processing of crystal-tolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) is also addressed in this road map.

  20. Road Map for Development of Crystal-Tolerant High Level Waste Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Josef; Vienna, John D.; Peeler, David; Fox, Kevin; Herman, Connie; Kruger, Albert A.

    2014-05-31

    This road map guides the research and development for formulation and processing of crystal-tolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) is also addressed in this road map.

  1. Design optimization of cast Cu-Al-Be-B alloys for high clamping capacity

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    This paper investigated high-damping Cu-Al-Be-B cast alloys using metallographic analysis, X-ray diffraction (XRD) and electrical resistance measurements for transformation temperatures. The results showed that beryllium can stabilize β phase, resulting in a thermo-elastic martensite microstructure leading to high-damping capacity in cast Cu-Al-BeB alloys. Trace additions of boron to Cu-Al-Be alloys can significantly refine the grains, providing high strength and ductility to the alloys. A factorial design of experiment method was used to optimize the composition and properties of cast Cu-Al-BeB alloys. The optimal microstructure for thermo-elastic martensite can be obtained by adjusting the amounts of aluminum and beryllium to eutectoid or pseudo-eutectoid compositions. An optimized cast Cu-Al-Be-B alloy was developed to provide excellent mechanical properties, tensile strength σb = 767 MPa, elongation δ = 7.62 %, and damping capacity S. D.C =18.70%.

  2. DPP4 gene variation affects GLP-1 secretion, insulin secretion, and glucose tolerance in humans with high body adiposity

    DEFF Research Database (Denmark)

    Böhm, Anja; Wagner, Robert; Machicao, Fausto

    2017-01-01

    OBJECTIVE: Dipeptidyl-peptidase 4 (DPP-4) cleaves and inactivates the insulinotropic hormones glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide, collectively termed incretins. DPP-4 inhibitors entered clinical practice as approved therapeutics for type-2 diabetes in 2006. However......-BMI interaction effects were detected (p = 0.8). After stratification for body fat content, the SNP negatively affected glucose-stimulated GLP-1 levels (p = 0.0229), insulin secretion (p = 0.0061), and glucose tolerance (p = 0.0208) in subjects with high body fat content only. CONCLUSIONS: A common variant, i......, inter-individual variance in the responsiveness to DPP-4 inhibitors was reported. Thus, we asked whether genetic variation in the DPP4 gene affects incretin levels, insulin secretion, and glucose tolerance in participants of the TÜbingen Family study for type-2 diabetes (TÜF). RESEARCH DESIGN...

  3. Experimental factors that influence carbon monoxide tolerance of high-temperature proton-exchange membrane fuel cells

    Science.gov (United States)

    Kwon, Kyungjung; Yoo, Duck Young; Park, Jung Ock

    The poisoning effect of carbon monoxide (CO) on high-temperature proton-exchange membrane fuel cells (PEMFCs) is investigated with respect to CO concentration, operating temperature, fuel feed mode, and anode Pt loading. The loss in cell voltage when CO is added to pure hydrogen anode gas is a function of fuel utilization and anode Pt loading as well as obvious factors such as CO concentration, temperature and current density. The tolerance to CO can be varied significantly using a different experimental design of fuel utilization and anode Pt loading. A difference in cell performance with CO-containing hydrogen is observed when two cells with different flow channel geometries are used, although the two cells show similar cell performance with pure hydrogen. A different combination of fuel utilization, anode Pt loading and flow channel design can cause an order of magnitude difference in CO tolerance under identical experimental conditions of temperature and current density.

  4. Experimental factors that influence carbon monoxide tolerance of high-temperature proton-exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kyungjung; Yoo, Duck Young; Park, Jung Ock [Energy and Environment Lab, Samsung Advanced Institute of Technology, Nongseo-dong, Giheung-gu, Yongin-si, Gyeonggi-do 446-712 (Korea)

    2008-10-15

    The poisoning effect of carbon monoxide (CO) on high-temperature proton-exchange membrane fuel cells (PEMFCs) is investigated with respect to CO concentration, operating temperature, fuel feed mode, and anode Pt loading. The loss in cell voltage when CO is added to pure hydrogen anode gas is a function of fuel utilization and anode Pt loading as well as obvious factors such as CO concentration, temperature and current density. The tolerance to CO can be varied significantly using a different experimental design of fuel utilization and anode Pt loading. A difference in cell performance with CO-containing hydrogen is observed when two cells with different flow channel geometries are used, although the two cells show similar cell performance with pure hydrogen. A different combination of fuel utilization, anode Pt loading and flow channel design can cause an order of magnitude difference in CO tolerance under identical experimental conditions of temperature and current density. (author)

  5. Society of Automotive Engineers AS4074 family high-speed, fault-tolerant data communications standards for integrated avionics

    Science.gov (United States)

    Meyer, John W.

    The Society of Automotive Engineers (SAE) has been addressing the need for data buses in advanced avionics systems. Since 1979, the SAE has had task groups developing a family of commercial data bus standards designed specifically for the unique fault-tolerant requirements of avionics applications: AS4074.1 linear, token-passing multiplex data bus (LTPB), and AS4074.2 high-speed ring bus (HSRB). The author explains the background of the two bus standards, gives a brief overview of the two protocols, and reviews current and future SAE activities in the avionics data bus field. It is concluded that the SAE LTPB and HSRB satisfy the data latency needs of emerging avionics architectures, as well as the reliability and fault tolerance requirements. Because of their ability to be supplemented with higher data rate versions, they will continue to support emerging avionics architectures.

  6. EAM-based high-speed 100-km OFDM transmission featuring tolerant modulator operation enabled using SSII cancellation.

    Science.gov (United States)

    Chen, Hsing-Yu; Wei, Chia-Chien; Lu, I-Cheng; Chen, Yu-Chao; Chu, Hsuan-Hao; Chen, Jyehong

    2014-06-16

    In this study, a technique was developed to compensate for nonlinear distortion through cancelling subcarrier-to-subcarrier intermixing interference (SSII) in an electroabsorption modulator (EAM)-based orthogonal frequency-division multiplexing (OFDM) transmission system. The nonlinear distortion to be compensated for is induced by both EAM nonlinearity and fiber dispersion. Because an OFDM signal features an inherently high peak-to-average power ratio, a trade-off exists between the optical modulation index (OMI) and modulator nonlinearity. Therefore, the nonlinear distortion limits the operational tolerance of the bias voltage and the driving power to a small region. After applying the proposed SSII cancellation, the OMI of an OFDM signal was increased yielding only a small increment of nonlinear distortion, and the tolerance region of the operational conditions was also increased. By employing the proposed scheme, this study successfully demonstrates 50-Gbps OFDM transmission over 100-km dispersion-uncompensated single-mode fiber based on a single 10-GHz EAM.

  7. Achieving high thermal conductivity from AlN films deposited by high-power impulse magnetron sputtering

    Science.gov (United States)

    Ait Aissa, K.; Semmar, N.; Achour, A.; Simon, Q.; Petit, A.; Camus, J.; Boulmer-Leborgne, C.; Djouadi, M. A.

    2014-09-01

    We report on thermal conductivity measurements of aluminum nitride (AlN) films using the fast pulsed photo-thermal technique. The films were deposited by high-power impulse magnetron sputtering with different thicknesses ranging from 1000 to 8000 nm on (1 0 0) oriented silicon substrates. The films were characterized by x-ray diffraction (XRD), Raman spectroscopy, profilometry, scanning electron microscopy and atomic force microscopy. The XRD measurements showed that AlN films were textured along the (0 0 2) direction. Moreover, x-ray rocking curve measurements indicated that the crystalline quality of AlN was improved with the increase in film thickness. The thermal conductivities of the samples were found to rapidly increase when the film thickness increased up to 3300 nm and then showed a tendency to remain constant. A thermal boundary resistance as low as 8 × 10-9 W-1 K m2 and a thermal conductivity as high as 250 ± 50 W K-1 m-1 were obtained for the AlN films, at room temperature. This high thermal conductivity value is close to that of an AlN single crystal and highlights the potential of these films as a dielectric material for thermal management.

  8. High tolerance to salinity and herbivory stresses may explain the expansion of Ipomoea cairica to salt marshes.

    Directory of Open Access Journals (Sweden)

    Gang Liu

    Full Text Available BACKGROUND: Invasive plants are often confronted with heterogeneous environments and various stress factors during their secondary phase of invasion into more stressful habitats. A high tolerance to stress factors may allow exotics to successfully invade stressful environments. Ipomoea cairica, a vigorous invader in South China, has recently been expanding into salt marshes. METHODOLOGY/PRINCIPAL FINDINGS: To examine why this liana species is able to invade a stressful saline environment, we utilized I. cairica and 3 non-invasive species for a greenhouse experiment. The plants were subjected to three levels of salinity (i.e., watered with 0, 4 and 8 g L(-1 NaCl solutions and simulated herbivory (0, 25 and 50% of the leaf area excised treatments. The relative growth rate (RGR of I. cairica was significantly higher than the RGR of non-invasive species under both stress treatments. The growth performance of I. cairica was not significantly affected by either stress factor, while that of the non-invasive species was significantly inhibited. The leaf condensed tannin content was generally lower in I. cairica than in the non-invasive I. triloba and Paederia foetida. Ipomoea cairica exhibited a relatively low resistance to herbivory, however, its tolerance to stress factors was significantly higher than either of the non-invasive species. CONCLUSIONS/SIGNIFICANCE: This is the first study examining the expansion of I. cairica to salt marshes in its introduced range. Our results suggest that the high tolerance of I. cairica to key stress factors (e.g., salinity and herbivory contributes to its invasion into salt marshes. For I. cairica, a trade-off in resource reallocation may allow increased resources to be allocated to tolerance and growth. This may contribute to a secondary invasion into stressful habitats. Finally, we suggest that I. cairica could spread further and successfully occupy salt marshes, and countermeasures based on herbivory could be

  9. Influence of high-temperature processing on the surface properties of bulk AlN substrates

    Science.gov (United States)

    Tojo, Shunsuke; Yamamoto, Reo; Tanaka, Ryohei; Thieu, Quang Tu; Togashi, Rie; Nagashima, Toru; Kinoshita, Toru; Dalmau, Rafael; Schlesser, Raoul; Murakami, Hisashi; Collazo, Ramón; Koukitu, Akinori; Monemar, Bo; Sitar, Zlatko; Kumagai, Yoshinao

    2016-07-01

    Deep-level luminescence at 3.3 eV related to the presence of Al vacancies (VAl) was observed in room temperature photoluminescence (RT-PL) spectra of homoepitaxial AlN layers grown at 1450 °C by hydride vapor-phase epitaxy (HVPE) and cooled to RT in a mixture of H2 and N2 with added NH3. However, this luminescence disappeared after removing the near surface layer of AlN by polishing. In addition, the deep-level luminescence was not observed when the post-growth cooling of AlN was conducted without NH3. Secondary ion mass spectrometry (SIMS) studies revealed that although the point defect density of the interior of the AlN layers remained low, the near surface layer cooled in the presence of NH3 was contaminated by Si impurities due to both suppression of the surface decomposition by the added NH3 and volatilization of Si by decomposition of the quartz reactor walls at high temperatures. The deep-level luminescence reappeared after the polished AlN wafers were heated in presence of NH3 at temperatures above 1400 °C. The surface contamination by Si is thought to generate VAl near the surface by lowering their formation energy due to the Fermi level effect, resulting in deep-level luminescence at 3.3 eV caused by the shallow donor (Si) to VAl transition.

  10. Superconductivity in Group III-V Semiconductor AlN Under High Pressure

    Directory of Open Access Journals (Sweden)

    G. Selva Dancy

    2015-09-01

    Full Text Available The electronic properties of cubic zinc blende type group III-V semiconductor AlN under pressure is studied using full potential linear muffin-tin orbital (FP-LMTO method. At normal pressure, AlN is an indirect bandgap semiconductor with band gap value 4.56 eV. When the pressure is increased, there is enhanced overlapping between the wave functions of the neighboring atoms. As a result the widths of the valence and empty conduction bands increase. These changes lead to the narrowing and indirect closing of the band gaps in AlN (metallization. On further increase of pressure, AlN becomes a superconductor and AlN comes under the class of electron-phonon-mediated high pressure superconductors. The superconducting transition temperatures (Tc of AlN are obtained as a function of pressure for the CsCl structure. It is also confirmed that the metallization, structural phase transition and onset of superconductivity do not occur simultaneously in this compound. DOI: http://dx.doi.org/10.17807/orbital.v7i3.628

  11. Al based ultra-fine eutectic with high room temperature plasticity and elevated temperature strength

    Energy Technology Data Exchange (ETDEWEB)

    Tiwary, C.S., E-mail: cst311@gmail.com [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kashyap, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India); Kim, D.H. [Center for Non-Crystalline Materials, Department of Metallurgical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012, Karnataka (India)

    2015-07-15

    Developments of aluminum alloys that can retain strength at and above 250 °C present a significant challenge. In this paper we report an ultrafine scale Al–Fe–Ni eutectic alloy with less than 3.5 at% transition metals that exhibits room temperature ultimate tensile strength of ~400 MPa with a tensile ductility of 6–8%. The yield stress under compression at 300 °C was found to be 150 MPa. We attribute it to the refinement of the microstructure that is achieved by suction casting in copper mold. The characterization using scanning and transmission electron microscopy (SEM and TEM) reveals an unique composite structure that contains the Al–Al{sub 3}Ni rod eutectic with spacing of ~90 nm enveloped by a lamellar eutectic of Al–Al{sub 9}FeNi (~140 nm). Observation of subsurface deformation under Vickers indentation using bonded interface technique reveals the presence of extensive shear banding during deformation that is responsible for the origin of ductility. The dislocation configuration in Al–Al{sub 3}Ni eutectic colony indicates accommodation of plasticity in α-Al with dislocation accumulation at the α-Al/Al{sub 3}Ni interface boundaries. In contrast the dislocation activities in the intermetallic lamellae are limited and contain set of planner dislocations across the plates. We present a detailed analysis of the fracture surface to rationalize the origin of the high strength and ductility in this class of potentially promising cast alloy.

  12. Amorphous and nanocrystalline phase formation in highly-driven Al-based binary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kalay, Yunus Eren [Iowa State Univ., Ames, IA (United States)

    2009-01-01

    Remarkable advances have been made since rapid solidification was first introduced to the field of materials science and technology. New types of materials such as amorphous alloys and nanostructure materials have been developed as a result of rapid solidification techniques. While these advances are, in many respects, ground breaking, much remains to be discerned concerning the fundamental relationships that exist between a liquid and a rapidly solidified solid. The scope of the current dissertation involves an extensive set of experimental, analytical, and computational studies designed to increase the overall understanding of morphological selection, phase competition, and structural hierarchy that occurs under far-from equilibrium conditions. High pressure gas atomization and Cu-block melt-spinning are the two different rapid solidification techniques applied in this study. The research is mainly focused on Al-Si and Al-Sm alloy systems. Silicon and samarium produce different, yet favorable, systems for exploration when alloyed with aluminum under far-from equilibrium conditions. One of the main differences comes from the positions of their respective T0 curves, which makes Al-Si a good candidate for solubility extension while the plunging T0 line in Al-Sm promotes glass formation. The rapidly solidified gas-atomized Al-Si powders within a composition range of 15 to 50 wt% Si are examined using scanning and transmission electron microscopy. The non-equilibrium partitioning and morphological selection observed by examining powders at different size classes are described via a microstructure map. The interface velocities and the amount of undercooling present in the powders are estimated from measured eutectic spacings based on Jackson-Hunt (JH) and Trivedi-Magnin-Kurz (TMK) models, which permit a direct comparison of theoretical predictions. For an average particle size of 10 {micro}m with a Peclet number of ~0.2, JH and TMK deviate from

  13. Undamped low-energy plasmon in AlH3 at high pressure

    Science.gov (United States)

    Gurtubay, I. G.; Rousseau, B.; Bergara, A.

    2010-08-01

    Pressure strongly modifies electronic and optical properties of solids. In this work we report ab initio time-dependent density-functional theory calculations of the dielectric response of the high-pressure metallic phase of aluminum hydride (AlH3) within the random-phase approximation. Besides the conventional free-electronlike plasmon, which is highly damped, low-energy transitions between states near the Fermi level that appear in this metallized phase give rise to a low-energy undamped collective mode. This feature is expected to induce an abrupt edge in the experimentally measured reflectivity just below 1 eV and also affect electronic correlations close to the Fermi energy. Our work shows that AlH3 is basically a hydrogen sublattice weakly perturbed by Al atoms.

  14. Solution-processed Al-chelated gelatin for highly transparent non-volatile memory applications

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Yu-Chi; Wang, Yeong-Her, E-mail: yhw@ee.ncku.edu.tw [Institute of Microelectronics and Department of Electrical Engineering, Advanced Optoelectronic Technology Center, National Cheng-Kung University, Tainan 701 Taiwan (China)

    2015-03-23

    Using the biomaterial of Al-chelated gelatin (ACG) prepared by sol-gel method in the ITO/ACG/ITO structure, a highly transparent resistive random access memory (RRAM) was obtained. The transmittance of the fabricated device is approximately 83% at 550 nm while that of Al/gelatin/ITO is opaque. As to the ITO/gelatin/ITO RRAM, no resistive switching behavior can be seen. The ITO/ACG/ITO RRAM shows high ON/OFF current ratio (>10{sup 5}), low operation voltage, good uniformity, and retention characteristics at room temperature and 85 °C. The mechanism of the ACG-based memory devices is presented. The enhancement of these electrical properties can be attributed to the chelate effect of Al ions with gelatin. Results show that transparent ACG-based memory devices possess the potential for next-generation resistive memories and bio-electronic applications.

  15. Rhombohedral AlPt films formed by self-propagating, high temperature synthesis.

    Energy Technology Data Exchange (ETDEWEB)

    Adams, David Price; Rodriguez, Mark Andrew; Kotula, Paul Gabriel

    2005-11-01

    High-purity AlPt thin films prepared by self-propagating, high temperature combustion synthesis show evidence for a new rhombohedral phase. Sputter deposited Al/Pt multilayers of various designs are reacted at different rates in air and in vacuum, and each form a new trigonal/hexagonal aluminide phase with unit cell parameters a = 15.571(8) {angstrom}, c = 5.304(1) {angstrom}, space group R-3 (148), and Z, the number of formula units within a unit cell, = 39. The lattice is isostructural to that of the AlPd R-3 lattice as reported by Matkovic and Schubert (Matkovic, 1977). Reacted films have a random in-plane crystallographic texture, a modest out-of-plane (001) texture, and equiaxed grains with dimensions on the order of film thickness.

  16. High radiation and desiccation tolerance of nitrogen-fixing cultures of the cyanobacterium Anabaena sp. strain PCC 7120 emanates from genome/proteome repair capabilities.

    Science.gov (United States)

    Singh, Harinder; Anurag, Kirti; Apte, Shree Kumar

    2013-10-12

    The filamentous nitrogen-fixing cyanobacterium, Anabaena sp. strain PCC 7120 was found to tolerate very high doses of (60)Co-gamma radiation or prolonged desiccation. Post-stress, cells remained intact and revived all the vital functions. A remarkable capacity to repair highly disintegrated genome and recycle the damaged proteome appeared to underlie such high radioresistance and desiccation tolerance. The close similarity observed between the cellular response to irradiation or desiccation stress lends strong support to the notion that tolerance to these stresses may involve similar mechanisms.

  17. Protective Effect of the Sputtered TiAlCrAg Coating on the High-Temperature Oxidation and Hot Corrosion Resistance of Ti-Al-Nb Alloy

    Institute of Scientific and Technical Information of China (English)

    Yanjun XI; Fuhui WANG; Lianlong HE

    2004-01-01

    The effect of a sputtered Ti-48Al-8Cr-2Ag (at. pct) coating on the oxidation resistance of the cast Ti-46.5Al-5Nb (at. pct) alloy was investigated in air at 1000~1100℃. Hot corrosion in molten 75 wt pct Na2SO4+25 wt pct K2SO4 was investigated at 900℃. The scale on the cast TiAlNb tends to spall in air, while the scale on coating is very adherent. The sputtered Ti-48Al-8Cr-2Ag coating remarkably improved high temperature oxidation resistance of the cast Ti-46.5Al-5Nb alloy because of the formation of an adherent Al2O3 scale. Due to the inward diffusion of Cr,Kirkendall voids were found at the coating/substrate interface. TiAlCrAg coating provided excellent hot corrosion resistance for TiAlNb alloy in molten 75 wt pct Na2SO4+25 wt pct K2SO4 at 900℃ due to the formation of a continuous Al2O3 scale.

  18. Performance of AlGaN/GaN High Electron Mobility Transistors with AlSiN Passivation

    Science.gov (United States)

    2010-03-04

    NOTES 20100402017 14. ABSTRACT This program was focused on the development of alternative and superior dielectric passivations to AlGaN/ GaN HEMT ...efficiency were demonstrated. Index Terms GaN , MODFETs, Microwave power FETs, passivation. I. INTRODUCTION THE AlGaN/ GaN HEMT has been studied for its...deposition (LPCVD) system onto etched mesa-isolated AlGaN/ GaN HEMT structures with 25 nm Alo.25Gao.75N barriers grown on S.I. SiC. Dielectric

  19. Investigation of trap states in Al2O3 InAlN/GaN metal-oxide-semiconductor high-electron-mobility transistors

    Science.gov (United States)

    Zhang, Peng; Zhao, Sheng-Lei; Xue, Jun-Shuai; Zhu, Jie-Jie; Ma, Xiao-Hua; Zhang, Jin-Cheng; Hao, Yue

    2015-12-01

    In this paper the trapping effects in Al2O3/In0.17Al0.83N/GaN MOS-HEMT (here, HEMT stands for high electron mobility transistor) are investigated by frequency-dependent capacitance and conductance analysis. The trap states are found at both the Al2O3/InAlN and InAlN/GaN interface. Trap states in InAlN/GaN heterostructure are determined to have mixed de-trapping mechanisms, emission, and tunneling. Part of the electrons captured in the trap states are likely to tunnel into the two-dimensional electron gas (2DEG) channel under serious band bending and stronger electric field peak caused by high Al content in the InAlN barrier, which explains the opposite voltage dependence of time constant and relation between the time constant and energy of the trap states. Project supported by the Program for National Natural Science Foundation of China (Grant Nos. 61404100 and 61306017).

  20. High-Temperature Thermometer Using Cr-Doped GdAlO3 Broadband Luminescence

    Science.gov (United States)

    Eldridge, Jeffrey; Chambers, Matthew

    2011-01-01

    A new concept has been developed for a high-temperature luminescence-based optical thermometer that both shows the desired temperature sensitivity in the upper temperature range of present state-of-the-art luminescence thermometers (above 1,300 C), while maintaining substantial stronger luminescence signal intensity that will allow these optical thermometers to operate in the presence of the high thermal background radiation typical of industrial applications. This objective is attained by using a Cr-doped GdAlO3 (Cr:GdAlO3) sensor with an orthorhombic perovskite structure, resulting in broadband luminescence that remains strong at high temperature due to the favorable electron energy level spacing of Cr:GdAlO3. The Cr:GdAlO3 temperature (and pressure) sensor can be incorporated into, or applied onto, a component s surface when a non-contact surface temperature measurement is desired, or alternatively, the temperature sensor can be attached to the end of a fiber-optic probe that can then be positioned at the location where the temperature measurement is desired. In the case of the fiber-optic probe, both the pulsed excitation and the luminescence emission travel through the fiber-optic light guide. In either case, a pulsed light source provides excitation of the luminescence, and the broadband luminescence emission is collected. Real-time temperature measurements are obtain ed using a least-squares fitting algorithm that determines the luminescence decay time, which has a known temperature dependence established by calibration. Due to the broad absorption and emission bands for Cr:GdAlO3, there is considerable flexibility in the choice of excitation wavelength and emission wavelength detection bands. The strategic choice of the GdAlO3 host is based on its high crystal field, phase stability, and distorted symmetry at the Cr3+ occupation sites. The use of the broadband emission for temperature sensing at high temperatures is a key feature of the invention and is

  1. Performance comparison of AlTiC and AlTiB master alloys in grain refinement of commercial and high purity aluminum

    Institute of Scientific and Technical Information of China (English)

    LI Jian-guo; HUANG Min; MA Mo; YE Wei; LIU Dong-yu; SONG Dong-ming; BAI Bing-zhe; FANG Hong-sheng

    2006-01-01

    For further knowledge about the refining performance of AlTiC master alloys, Al5.5Ti0.25C and Al6.5Ti0.5C master alloys containing high Ti and C content were prepared and used in grain refining experiments of 99.8% commercial pure aluminum(CPAl). Their performance was compared with two types of Al5TilB refiners whose performance was nowadays considered to be the best. These two types of master alloys show similar refining efficiency at the addition level of 0.2%. However, at the addition level of 0.5%, there still exists great performance difference between AlTiC and Al5TiB alloys in grain refinement of 99.98% and 99.995% high purity aluminum(HPAl). The growth of columnar grains is fully suppressed due to the refinement of AlTiC at the addition level of 0.5%. Also, at the same addition level, the grain refining experiments of Al3Ti0.15C and Al5Ti0.2C master alloys which have found initial commercial applications are conducted in the above-mentioned three types of pure aluminum.According to the experimental results, these two refiners of different compositions are both nonideal. The second phase particles extracted from each refiner were observed through TEM, while the nuclei of grains after grain refinement were observed through SEM. The results were analyzed through computation and comparison of the constitutional-supercooling parameter and the growth-restriction parameter whose values were determined by solute element in aluminum melt with different purity. Apparently,AlTiC master alloys with high content of Ti and C element have great refining potential.

  2. Derivation of Apollo 14 High-Al Basalts at Discrete Times: Rb-Sr Isotopic Constraints

    Science.gov (United States)

    Hui, H.; Neal, C. R.; Shih, C.-Y.; Nyquist, L. E.

    2012-03-01

    Four eruption episodes were identified for A-14 high-Al basalts. Rb-Sr isotopic data and ITE ratios show that their parental melt compositions of are correlated through mixing of evolved components with a relatively primitive magma ocean cumulate.

  3. High-pressure Al-rich hexagonal phases-What are their kin?

    DEFF Research Database (Denmark)

    Makovicky, Emil; Olsen, Lars Arnskov

    2008-01-01

    The hexagonal Al-rich high-pressure phases are members of a structural family with the same type of framework composed of double-ribbons of edge-sharing octahedra, but variably occupied trigonal and hexagonal channels. This family includes jaffeite, fluoborite, yeremeyevite, painite, and synthetic...

  4. Guiding of low-energy electrons by highly ordered Al2 O3 nanocapillaries

    DEFF Research Database (Denmark)

    Milosavljević, A.R.; Víkor, G.; Pešić, Z.D.;

    2007-01-01

    We report an experimental study of guided transmission of low-energy (200-350 eV) electrons through highly ordered Al2 O3 nanocapillaries with large aspect ratio (140 nm diameter and 15 μm length). The nanochannel array was prepared using self-ordering phenomena during a two-step anodization proc...

  5. Magnetron sputtering system stabilisation for high rate desposition of AlN films

    DEFF Research Database (Denmark)

    Fomin, A; Akhmatov, Vladislav; Selishchev, S

    1998-01-01

    The stabilisation of a planar magnetron sputtering system for reactive sputtering of AlN in a gaseous mixture of Ar and highly active NH3 was examined. The helical instability in the cathode plasma sheath was observed and methods for its damping were proposed. It was found that the deposition of c...

  6. Ka-Band AlGaN/GaN HEMT high power and driver amplifier MMICs

    NARCIS (Netherlands)

    Heijningen, M. van; Vliet, F.E. van; Quay, R.; Raay, F. van; Kiefer, R.; Mueller, S.; Krausse, D.; Seelmann-Eggebert, M.; Mikulla, M.; Schlechtweg, M.

    2005-01-01

    In this paper the MMIC technology, design and characterization of a high power amplifier and driver amplifier MMIC at 30 GHz in AlGaN/GaN HEMT technology are presented. The MMICs are designed using CPW technology on a 390 μm thick SiC substrate. The measured small-signal gain of the driver is 14 dB

  7. Surface modification of Al-Pb alloy by high current pulsed electron beam

    Institute of Scientific and Technical Information of China (English)

    LU You; LI Shi-long; AN Jian; LIU Yong-bing

    2006-01-01

    Al-Pb alloy was modified by high current pulsed electron beam and the microstructure, hardness and tribological characteristics were characterized by scanning electron microscopy, electronic microanalysis probe microanalysis, Knoop hardness indentation and pin-on-disc type wear testing machine. The results show that the microstructure and hardness can be greatly improved, and the modification layer consists of a molten zone, an overlapped zone of heat-affected and quasistatic thermal stress-affected zone and a transition zone followed by the substrate. The tribological properties of high current pulsed electron beam irradiated Al-Pb alloy are correspondingly improved largely. Optical observation and scanning electron microscopy analysis reveal that the low wear rate and lowest level in coefficient of friction at high load level for irradiated Al-Pb alloy are due to the formation of a lubricious tribolayer covering the worn surface, which is a mixture of Al2O3, Pb3O4 and silicate. The wear mode varies from oxidative wear at low load to film spalling at high load and, finally, adhesive wear.

  8. High cadmium-binding ability of a novel Colocasia esculenta metallothionein increases cadmium tolerance in Escherichia coli and tobacco.

    Science.gov (United States)

    Kim, Yeon-Ok; Patel, Darshan H; Lee, Dae-Seok; Song, Younho; Bae, Hyeun-Jong

    2011-01-01

    Experimental evidence in vivo as to the functional roles and binding properties to cadmium (Cd) of type-2 plants metallothionein (MT) has been limited thus far. We investigated the biological role of metallothionein from Colocasia esculenta (CeMT2b) in Escherichia coli and tobacco, and developed a new model for the relationship between Cd tolerance and Cd-binding ability. Heterologous expression of CeMT2b in Escherichia coli greatly enhanced Cd tolerance and accumulated Cd content as compared to control cells. The molecular weight of CeMT2b increased with Cd, and CeMT2b bound up to 5.96±1 molar ratio (Cd/protein). Under Cd stress, transgenic tobacco plants displayed much better seedling growth and high Cd accumulation than the wild type. The presence of an extra CXC motif in CeMT2b contributed to the enhanced Cd-tolerance. The present study provides the first insight into the ability of type-2 plant MT to bind physiological Cd.

  9. Identification by phenotypic and genetic approaches of an indigenous Saccharomyces cerevisiae wine strain with high desiccation tolerance.

    Science.gov (United States)

    Zambuto, Marianna; Romaniello, Rossana; Guaragnella, Nicoletta; Romano, Patrizia; Votta, Sonia; Capece, Angela

    2017-07-21

    During active dry yeast (ADY) production process, cells are exposed to multiple stresses, such as thermal, oxidative and hyperosmotic shock. Previously, by analysing cells in exponential growth phase, we selected an indigenous Saccharomyces cerevisiae wine strain, namely CD-6Sc, for its higher tolerance to desiccation and higher expression of specific desiccation stress-related genes in comparison to other yeast strains. In this study, we performed a desiccation treatment on stationary phase cells by comparing the efficacy of two different methods: a 'laboratory dry test' on a small scale (mild stress) and a treatment by spray-drying (severe stress), one of the most appropriate preservation method for yeasts and other micro-organisms. The expression of selected desiccation-related genes has been also assessed in order to validate predictive markers for desiccation tolerance. Our data demonstrate that the 'mild' and the 'severe' desiccation treatments give similar results in terms of cell recovery, but the choice of marker genes strictly depends on the growth phase in which cells undergo desiccation. The indigenous CD-6Sc was ultimately identified as a high dehydration stress-tolerant indigenous strain suitable for ADY production. This study highlights the exploitation of natural yeast biodiversity as a source of hidden technological features and as an alternative approach to strain improvement by genetic modifications. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Ultrasonic Al2O3 Ceramic Thermometry in High-Temperature Oxidation Environment

    Directory of Open Access Journals (Sweden)

    Yanlong Wei

    2016-11-01

    Full Text Available In this study, an ultrasonic temperature measurement system was designed with Al2O3 high-temperature ceramic as an acoustic waveguide sensor and preliminarily tested in a high-temperature oxidation environment. The test results indicated that the system can indeed work stably in high-temperature environments. The relationship between the temperature and delay time of 26 °C–1600 °C ceramic materials was also determined in order to fully elucidate the high-temperature oxidation of the proposed waveguide sensor and to lay a foundation for the further application of this system in temperatures as high as 2000 °C.

  11. Effects of AlN nucleation layers on the growth of AlN films using high temperature hydride vapor phase epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Balaji, M. [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); ACERDE, 452 rue des sources, 38920 Crolles (France); Crystal Growth Centre, Anna University-Chennai, Chennai 600025 (India); Claudel, A. [ACERDE, 452 rue des sources, 38920 Crolles (France); Fellmann, V. [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); Gelard, I. [ACERDE, 452 rue des sources, 38920 Crolles (France); Blanquet, E., E-mail: elisabeth.blanquet@simap.grenoble-inp.fr [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); Boichot, R. [Science et Ingenierie des Materiaux et des Procedes, Grenoble INP-CNRS-UJF, BP 75, 38402 Saint Martin d' Heres (France); Pierret, A. [Departement de Mesures Physiques, ONERA, Chemin de la Huniere, 91761 Palaiseau Cedex (France); CEA-CNRS Group ' NanoPhysique et SemiConducteurs' , INAC/SP2M/NPSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble, Cedex 9 (France); and others

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Growth of AlN Nucleation layers and its effect on high temperature AlN films quality were investigated. Black-Right-Pointing-Pointer AlN nucleation layers stabilizes the epitaxial growth of AlN and improves the surface morphology of AlN films. Black-Right-Pointing-Pointer Increasing growth temperature of AlN NLs as well as AlN films improves the structural quality and limits the formation of cracks. - Abstract: AlN layers were grown on c-plane sapphire substrates with AlN nucleation layers (NLs) using high temperature hydride vapor phase epitaxy (HT-HVPE). Insertion of low temperature NLs, as those typically used in MOVPE process, prior to the high temperature AlN (HT-AlN) layers has been investigated. The NLs surface morphology was studied by atomic force microscopy (AFM) and NLs thickness was measured by X-ray reflectivity. Increasing nucleation layer deposition temperature from 650 to 850 Degree-Sign C has been found to promote the growth of c-oriented epitaxial HT-AlN layers instead of polycrystalline layers. The growth of polycrystalline layers has been related to the formation of dis-oriented crystallites. The density of such disoriented crystallites has been found to decrease while increasing NLs deposition temperature. The HT-AlN layers have been characterized by X-ray diffraction {theta} - 2{theta} scan and (0 0 0 2) rocking curve measurement, Raman and photoluminescence spectroscopies, AFM and field emission scanning electron microscopy. Increasing the growth temperature of HT-AlN layers from 1200 to 1400 Degree-Sign C using a NL grown at 850 Degree-Sign C improves the structural quality as well as the surface morphology. As a matter of fact, full-width at half-maximum (FWHM) of 0 0 0 2 reflections was improved from 1900 to 864 arcsec for 1200 Degree-Sign C and 1400 Degree-Sign C, respectively. Related RMS roughness also found to decrease from 10 to 5.6 nm.

  12. AlGaN/GaN High Electron Mobility Transistors for High-Power and Low-Noise Applications

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaoguang; Dabiran Amir M; Hartmann Ralf; Chow Peter P

    2004-01-01

    The paper different aspects of MBE growth of nitride-based high electron mobility transistor (HEMT) and dilute-nitride, AlGaAsN-based, heterostructures were discussed. New growth and monitoring techniques developed at SVT were described and recent device results were presented.

  13. High salinity tolerance in eggs and fry of a brackish Esox lucius population

    DEFF Research Database (Denmark)

    Jørgensen, A.T.; Hansen, B.W.; Vismann, B.

    2010-01-01

    Knowledge on the biology and physiology of pike, Esox lucius L., populations inhabiting saline environments is scarce. An experimental setup was used to examine egg development and fry behaviour and growth under varying salinity levels in a brackish-water pike population from the western Baltic Sea....... Eggs and fry developed at 8.5 psu, which is higher than hitherto reported for other populations. Fry exhibited stress behaviour and reduced growth when subjected to salinities above 13 psu. This indicates that early life stages of E. lucius tolerate ambient salinity conditions equivalent to the natural...

  14. Microstructure/processing relationships in high-energy high-rate consolidated powder composites of Nb-stabilized Ti3Al+TiAl

    Energy Technology Data Exchange (ETDEWEB)

    Persad, C.; Lee, B.; Hou, C.; Eliezer, Z.; Marcus, H.L.

    1989-01-01

    A new approach to powder processing is employed in forming titanium aluminide composites. The processing consists of internal heating of a customized powder blend by a fast electrical discharge of a homopolar generator. The high-energy high-rate '1MJ in 1s' pulse permits rapid heating of an electrically conducting powder mixture in a cold wall die. This short time at temperature approach offers the opportunity to control phase transformations and the degree of microstructural coarsening not readily possible with standard powder-processing approaches. This paper describes the consolidation results of titanium aluminide-based powder-composite materials. The focus of this study was the definition of microstructure/processing relationships for each of the composite constituents, first as monoliths and then in composite forms. Non-equilibrium phases present in rapidly solidified TiAl powders are transformed to metastable intermediates en route to the equilibrium gamma phase.

  15. Association and linkage analysis of aluminum tolerance genes in maize.

    Directory of Open Access Journals (Sweden)

    Allison M Krill

    Full Text Available BACKGROUND: Aluminum (Al toxicity is a major worldwide constraint to crop productivity on acidic soils. Al becomes soluble at low pH, inhibiting root growth and severely reducing yields. Maize is an important staple food and commodity crop in acidic soil regions, especially in South America and Africa where these soils are very common. Al exclusion and intracellular tolerance have been suggested as two important mechanisms for Al tolerance in maize, but little is known about the underlying genetics. METHODOLOGY: An association panel of 282 diverse maize inbred lines and three F2 linkage populations with approximately 200 individuals each were used to study genetic variation in this complex trait. Al tolerance was measured as net root growth in nutrient solution under Al stress, which exhibited a wide range of variation between lines. Comparative and physiological genomics-based approaches were used to select 21 candidate genes for evaluation by association analysis. CONCLUSIONS: Six candidate genes had significant results from association analysis, but only four were confirmed by linkage analysis as putatively contributing to Al tolerance: Zea mays AltSB like (ZmASL, Zea mays aluminum-activated malate transporter2 (ALMT2, S-adenosyl-L-homocysteinase (SAHH, and Malic Enzyme (ME. These four candidate genes are high priority subjects for follow-up biochemical and physiological studies on the mechanisms of Al tolerance in maize. Immediately, elite haplotype-specific molecular markers can be developed for these four genes and used for efficient marker-assisted selection of superior alleles in Al tolerance maize breeding programs.

  16. Copper-phthalocyanine encapsulated into zeolite-Y with high Si/Al: An EPR study

    Science.gov (United States)

    Yahiro, Hidenori; Kimoto, Kunihiro; Yamaura, Hiroyuki; Komaguchi, Kenji; Lund, Anders

    2005-10-01

    Copper (II) phthalocyanine (CuPc) molecules encapsulated into zeolite-Y with Si/Al ratios of 2.7 and 410 were prepared by an in situ synthesis and characterized by UV-Vis and electron paramagnetic resonance (EPR) spectroscopies. Resolved Cu-hyperfine and N-superhyperfine structures were observed in the EPR spectrum of CuPc encapsulated into zeolite-Y with a high Si/Al ratio. UV-Vis and EPR studies as well as theoretical calculations suggest that the encapsulated CuPc molecule was distorted in zeolite-Y with keeping of the square-planar symmetry around the center copper (II) ion.

  17. Thermal stability of multilayered Pt-Al2O3 nanocoatings for high temperature CSP systems

    CSIR Research Space (South Africa)

    Nuru, ZY

    2015-10-01

    Full Text Available B), 115-120 Thermal stability of multilayered Pt-Al2O3 nanocoatings for high temperature CSP systems Z.Y. Nuru a, b, *, L. Kotsedi a, b, C.J. Arendse c, D. Motaung d, B. Mwakikunga d, K. Roro d, e, M. Maaza a, b a UNESCO-UNISA Africa Chair... Pretoria, South Africa e R&D Core-Energy, Council for Scientific and Industrial Research, P O Box 395, 0001 Pretoria, South Africa Abstract This contribution reports on the effect of thermal annealing on sputtered Pt–Al(sub2)O(sub3) multilayered...

  18. First results from the high-brightness x-ray spectroscopy beamline at ALS

    Energy Technology Data Exchange (ETDEWEB)

    Perera, R.C.C.; Ng, W.; Jones, G. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goal of high brightness at the sample for use in the X-ray Atomic and Molecular Spectroscopy (XAMS) science, surface and interface science, biology and x-ray optical development programs at ALS. X-ray absorption and time of flight photo emission measurements in 2 - 5 keV photon energy in argon along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

  19. Solid state amorphization in the Al-Fe binary system during high energy milling

    Energy Technology Data Exchange (ETDEWEB)

    Urban, P., E-mail: purban@us.es; Montes, J. M.; Cintas, J. [University of Seville, Department of Mechanical and Materials Engineering, ETSI, Camino de los Descubrimientos s/n, Seville, 41092 (Spain); Cuevas, F. G., E-mail: fgcuevas@dqcm.uhu.es [University of Huelva, Department of Chemistry and Materials Science, ETSI, Campus La Rábida, Carretera Palos s/n, Palos de la Frontera, Huelva, 21819 (Spain)

    2013-12-16

    In the present study, mechanical alloying (MA) of Al75Fe25 elemental powders mixture was carried out in argon atmosphere, using a high energy attritor ball mill. The microstructure of the milled products at different stages of milling was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The results showed that the amorphous phase content increased by increasing the milling time, and after 50 hours the amorphization process became complete. Heating the samples resulted in the crystallization of the synthesized amorphous alloys and the appearance of the equilibrium intermetallic compounds Al{sub 5}Fe{sub 2}.

  20. Limited tolerance by insects to high temperatures across tropical elevational gradients and the implications of global warming for extinction.

    Science.gov (United States)

    García-Robledo, Carlos; Kuprewicz, Erin K; Staines, Charles L; Erwin, Terry L; Kress, W John

    2016-01-19

    The critical thermal maximum (CTmax), the temperature at which motor control is lost in animals, has the potential to determine if species will tolerate global warming. For insects, tolerance to high temperatures decreases with latitude, suggesting that similar patterns may exist along elevational gradients as well. This study explored how CTmax varies among species and populations of a group of diverse tropical insect herbivores, the rolled-leaf beetles, across both broad and narrow elevational gradients. Data from 6,948 field observations and 8,700 museum specimens were used to map the elevational distributions of rolled-leaf beetles on two mountains in Costa Rica. CTmax was determined for 1,252 individual beetles representing all populations across the gradients. Initial morphological identifications suggested a total of 26 species with populations at different elevations displaying contrasting upper thermal limits. However, compared with morphological identifications, DNA barcodes (cytochrome oxidase I) revealed significant cryptic species diversity. DNA barcodes identified 42 species and haplotypes across 11 species complexes. These 42 species displayed much narrower elevational distributions and values of CTmax than the 26 morphologically defined species. In general, species found at middle elevations and on mountaintops are less tolerant to high temperatures than species restricted to lowland habitats. Species with broad elevational distributions display high CTmax throughout their ranges. We found no significant phylogenetic signal in CTmax, geography, or elevational range. The narrow variance in CTmax values for most rolled-leaf beetles, especially high-elevation species, suggests that the risk of extinction of insects may be substantial under some projected rates of global warming.

  1. ωo phase precipitation in annealed high Nb containing TiAl alloys

    Directory of Open Access Journals (Sweden)

    Lin Song

    2015-04-01

    Full Text Available The ordered ω phases in high Nb containing TiAl (Nb-TiAl alloys have been garnering increasing attention in the recent years. However, the investigations on the Nb dependence on the ωo precipitation are scarce. In this study, the effect of Nb content on the ωo precipitation in high Nb (6–10 at% containing TiAl alloys after long-time annealing at 850 °C has been studied. The results show that small ordered ω particles in the retained βo phase cannot be discerned under scanning electron microscope (SEM but can be observed using transmission electron microscopy (TEM. Although the Nb segregation can be eliminated after the homogenization heat treatment, the ωo phase precipitated in all the alloys studied after annealing at 850 °C. TEM examination reveals that the orientation relationship between the ωo and α2 phases can be derived as: [0001]ωo//[112̄0]α2; (112̄0ωo//(0001α2, which indicates that the ωo phase is directly transformed from the parent α2 phase. Small γ particles are also observed within the ωo areas. The α2→ωo+γ decomposition process is expected during annealing. It is concluded that ωo phase is an equilibrium phase in high Nb-TiAl alloys at 850 °C.

  2. High Temperature Oxidation and Microstructural Evolution of Modified MCrAlY Coatings

    Science.gov (United States)

    Pulci, Giovanni; Tirillò, Jacopo; Marra, Francesco; Sarasini, Fabrizio; Bellucci, Alessandra; Valente, Teodoro; Bartuli, Cecilia

    2013-11-01

    Thermal sprayed MCrAlY coatings are widely used as a bond coat in thermal barrier systems to protect the substrate from corrosion and high temperature oxidation and to improve the compatibility between the ceramic top coat and metallic substrate. In this paper, the high temperature oxidation resistance of MCrAlY coatings with modified compositions was evaluated; in particular, the effect of the addition of reactive and refractory elements (Ta, Re, Si, and Hf) was investigated. MCrAlY coatings were obtained by high velocity oxygen fuel spray and vacuum plasma spray techniques; samples were exposed to air at 1423 K (1150 °C) and the oxidation kinetics were evaluated by measuring the thickness of the thermally grown oxide (TGO) scale at several exposure times. Experimental data confirmed that the oxidation resistance of MCrAlY coatings is strictly related to the amount of the reactive and refractory elements in the starting powders and that a thorough understanding of the microstructural modifications taking place during oxidation is essential for controlling TGO growth and thermal barriers' durability.

  3. ωo phase precipitation in annealed high Nb containing TiAl alloys

    Institute of Scientific and Technical Information of China (English)

    Lin Song; Cong Peng; Xiangjun Xu; Li You; Yanli Wang; Junpin Lin

    2015-01-01

    The orderedωphases in high Nb containing TiAl (Nb-TiAl) alloys have been garnering increasing attention in the recent years. However, the investigations on the Nb dependence on theωo precipitation are scarce. In this study, the effect of Nb content on theωo precipitation in high Nb (6–10 at%) containing TiAl alloys after long-time annealing at 850 1C has been studied. The results show that small orderedωparticles in the retainedβo phase cannot be discerned under scanning electron microscope (SEM) but can be observed using transmission electron microscopy (TEM). Although the Nb segregation can be eliminated after the homogenization heat treatment, theωo phase precipitated in all the alloys studied after annealing at 850 1C. TEM examination reveals that the orientation relationship between theωo andα2 phases can be derived as:[0001]ωo//[112̄0]α2; (112̄0)ωo//(0001)α2, which indicates that the ωo phase is directly transformed from the parent α2 phase. Small γ particles are also observed within theωo areas. Theα2-ωo þγdecomposition process is expected during annealing. It is concluded thatωo phase is an equilibrium phase in high Nb-TiAl alloys at 850 1C.

  4. Monoclinic high-pressure polymorph of AlOOH predicted from first principles

    Science.gov (United States)

    Zhong, Xin; Hermann, Andreas; Wang, Yanchao; Ma, Yanming

    2016-12-01

    Aluminum oxide hydroxide, AlOOH, is a prototypical hydrous mineral in the geonomy. The study of the high-pressure phase evolution of AlOOH is of fundamental importance in helping to understand the role of hydrous minerals in the water storage and transport in Earth, as in other planets. Here, we have systematically investigated the high-pressure phase diagram of AlOOH up to 550 GPa using the efficient crystal structure analysis by particle swarm optimization (CALYPSO) algorithm in conjunction with first principles calculations. We predict a peculiar monoclinic phase (space group P 21/c , 16 atoms/cell, Z =4 ) as the most stable phase for AlOOH above 340 GPa. The occurrence of this new phase results in the breakup of symmetric linear O-H-O hydrogen bonds into asymmetric, bent O-H-O linkages and in sevenfold coordinated metal cations. The new P 21/c phase turns out to be a universal high-pressure phase in group 13 oxide hydroxides, and stable for both compressed GaOOH and InOOH. The formation of the new phase in all compounds is favored by volume reduction due to denser packing.

  5. High Density Hydrogen Storage System Demonstration Using NaAlH4 Based Complex Compound Hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Daniel A. Mosher; Xia Tang; Ronald J. Brown; Sarah Arsenault; Salvatore Saitta; Bruce L. Laube; Robert H. Dold; Donald L. Anton

    2007-07-27

    This final report describes the motivations, activities and results of the hydrogen storage independent project "High Density Hydrogen Storage System Demonstration Using NaAlH4 Based Complex Compound Hydrides" performed by the United Technologies Research Center under the Department of Energy Hydrogen Program, contract # DE-FC36-02AL67610. The objectives of the project were to identify and address the key systems technologies associated with applying complex hydride materials, particularly ones which differ from those for conventional metal hydride based storage. This involved the design, fabrication and testing of two prototype systems based on the hydrogen storage material NaAlH4. Safety testing, catalysis studies, heat exchanger optimization, reaction kinetics modeling, thermochemical finite element analysis, powder densification development and material neutralization were elements included in the effort.

  6. High-pressure x-ray diffraction of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saksl, Karel; Rasmussen, Helge Kildahl

    2001-01-01

    The effect of pressure on the structural stability of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals forming from a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass with a supercooled liquid region of 44 K has been investigated by in situ high-pressure angle-dispersive x-ray powder diffraction at ambient...... temperature using synchrotron radiation. The icosahedral quasicrystal structure is retained up to the highest hydrostatic pressure used (approximately 28 GPa) and is reversible after decompression. The bulk modulus at zero pressure and its pressure derivative of the icosahedral Zr-Al-Ni-Cu-Ag quasicrystal...... are 99.10+/-1.26 GPa and 4.25+/-0.16, respectively. The compression behavior of different Bragg peaks is isotropic and the full width at half maximum of each peak remains almost unchanged during compression, indicating no anisotropic elasticity and no defects in the icosahedral Zr...

  7. Microstructural evolution of Ti-6Al-7Nb alloy during high pressure torsion

    Directory of Open Access Journals (Sweden)

    Tiago Santos Pinheiro

    2012-10-01

    Full Text Available Ti-6Al-7Nb alloys are being evaluated for biomedical applications, in substitution of the more conventional Ti-6Al-7V. Both types of alloys present a microstructure containing the α and the β phases, which result in good compromise for mechanical applications. In the present work Ti-6Al-7Nb alloys were processed by High Pressure Torsion (HPT, varying the number of revolutions and thus the total imposed strain. X-Ray Diffraction (XRD results revealed the formation of different crystallographic textures in samples subjected to HPT. Microhardness distribution, across the diameters of the disks, is rather homogeneous for all samples, with higher values for those subjected to 03 and 05 turns. Transmission electron microscopy (TEM micrographs have showed that an ultra-fine grained microstructure was obtained in all the samples.

  8. Soft Magnetic Properties of High-Entropy Fe-Co-Ni-Cr-Al-Si Thin Films

    Directory of Open Access Journals (Sweden)

    Pei-Chung Lin

    2016-08-01

    Full Text Available Soft magnetic properties of Fe-Co-Ni-Al-Cr-Si thin films were studied. As-deposited Fe-Co-Ni-Al-Cr-Si nano-grained thin films showing no magnetic anisotropy were subjected to field-annealing at different temperatures to induce magnetic anisotropy. Optimized magnetic and electrical properties of Fe-Co-Ni-Al-Cr-Si films annealed at 200 °C are saturation magnetization 9.13 × 105 A/m, coercivity 79.6 A/m, out-of-plane uniaxial anisotropy field 1.59 × 103 A/m, and electrical resistivity 3.75 μΩ·m. Based on these excellent properties, we employed such films to fabricate magnetic thin film inductor. The performance of the high entropy alloy thin film inductors is superior to that of air core inductor.

  9. Nanoscale investigation of AlGaN/GaN-on-Si high electron mobility transistors.

    Science.gov (United States)

    Fontserè, A; Pérez-Tomás, A; Placidi, M; Llobet, J; Baron, N; Chenot, S; Cordier, Y; Moreno, J C; Jennings, M R; Gammon, P M; Fisher, C A; Iglesias, V; Porti, M; Bayerl, A; Lanza, M; Nafría, M

    2012-10-05

    AlGaN/GaN HEMTs are devices which are strongly influenced by surface properties such as donor states, roughness or any kind of inhomogeneity. The electron gas is only a few nanometers away from the surface and the transistor forward and reverse currents are considerably affected by any variation of surface property within the atomic scale. Consequently, we have used the technique known as conductive AFM (CAFM) to perform electrical characterization at the nanoscale. The AlGaN/GaN HEMT ohmic (drain and source) and Schottky (gate) contacts were investigated by the CAFM technique. The estimated area of these highly conductive pillars (each of them of approximately 20-50 nm radius) represents around 5% of the total contact area. Analogously, the reverse leakage of the gate Schottky contact at the nanoscale seems to correlate somehow with the topography of the narrow AlGaN barrier regions producing larger currents.

  10. First-principles study of structural stabilities of AlH3 under high pressure

    Science.gov (United States)

    Feng, Wenxia; Cui, Shouxin; Feng, Min

    2014-07-01

    The structural stabilities and electronic properties of AlH3 under high pressure are investigated by using the plane-wave pseudopotential method. Our results demonstrate that the sequence of the pressure-induced phase transition is Fd 3 bar m(β) → cmcm(α ') → R 3 bar c(α) → Pnma(hp 1) → Pm 3 bar n(hp 2), and the transition pressures are 0.49, 0.91, 47, and 70 GPa, respectively. Im 3 bar m , Pnnm(γ) and P63/m structures are not stable in the 0-100 GPa. β, α ', α, and hp1 structures of AlH3 are nonmetals, while Pm 3 bar n structure of AlH3 is metallic, and the pressure-induced metallization is ascribed to phase transition under higher compression.

  11. A Review of Mold Flux Development for the Casting of High-Al Steels

    Science.gov (United States)

    Wang, Wanlin; Lu, Boxun; Xiao, Dan

    2016-02-01

    Mold flux plays key roles during the continuous casting process of molten steel, which accounts for the quality of final slabs. With the development of advanced high strength steels (AHSS), certain amounts of Al have been added into steels that would introduce severe slag/metal interaction problems during process of continuous casting. The reaction is between Al and SiO2 that is the major component in the mold flux system. Intensive efforts have been conducted to optimize the mold flux and a CaO-Al2O3-based mold flux system has been proposed, which shows the potential to be applied for the casting process of AHSS. The latest developments for this new mold flux system were summarized with the aim to offer technical guidance for the design of new generation mold flux system for the casting of AHSS.

  12. Botulinum toxin detection using AlGaN /GaN high electron mobility transistors

    Science.gov (United States)

    Wang, Yu-Lin; Chu, B. H.; Chen, K. H.; Chang, C. Y.; Lele, T. P.; Tseng, Y.; Pearton, S. J.; Ramage, J.; Hooten, D.; Dabiran, A.; Chow, P. P.; Ren, F.

    2008-12-01

    Antibody-functionalized, Au-gated AlGaN /GaN high electron mobility transistors (HEMTs) were used to detect botulinum toxin. The antibody was anchored to the gate area through immobilized thioglycolic acid. The AlGaN /GaN HEMT drain-source current showed a rapid response of less than 5s when the target toxin in a buffer was added to the antibody-immobilized surface. We could detect a range of concentrations from 1to10ng/ml. These results clearly demonstrate the promise of field-deployable electronic biological sensors based on AlGaN /GaN HEMTs for botulinum toxin detection.

  13. Segregation Behaviour of Third Generation Advanced High-Strength Mn-Al Steels

    Directory of Open Access Journals (Sweden)

    A. Grajcar

    2012-04-01

    Full Text Available The paper addresses the macro- and microsegregation of alloying elements in the new-developed Mn-Al TRIP steels, which belong to the third generation of advanced high-strength steels (AHSS used in the automotive industry. The segregation behaviour both in the as-cast state and after hot forging was assessed in the macro scale by OES and by EDS measurements in different structural constituents. The structural investigations were carried out using light and scanning electron microscopy. A special attention was paid to the effect of Nb microaddition on the structure and the segregation of alloying elements. The tendency of Mn and Al to macrosegregation was found. It is difficult to remove in Nb-free steels. Microsegregation of Mn and Al between austenite and ferritic structural constituents can be removed.

  14. Influences of Al2O3 grain size on high-temperature oxidation of nano-Ni/Al2O3 composites

    Directory of Open Access Journals (Sweden)

    Hai Vu Pham

    2016-03-01

    Full Text Available Two 5 vol% Ni/Al2O3 composites with the difference in Al2O3 grain size were fabricated by pulsed electric current sintering technique to investigate the influence of Al2O3 grain size on oxidation behavior of the composites. Average Al2O3 grain sizes of two fabricated composites were 1.1 μm and 0.5 μm after sintering. Oxidation tests were conducted at temperatures ranging from 1100 to 1350 °C for 1–48 h in air. A thin NiAl2O4 layer was observed in exposed surface of samples after oxidation. An oxidized zone that consisted of Al2O3 matrix and NiAl2O4 grains was defined. Growth of the oxidized zone obeyed the parabolic law. Influences of Al2O3 grain size on high-temperature oxidation of the composites were discussed.

  15. In-Situ Studies of Structure Transformation and Al Coordination of KAl(MoO42 during Heating by High Temperature Raman and 27Al NMR Spectroscopies

    Directory of Open Access Journals (Sweden)

    Min Wang

    2017-03-01

    Full Text Available Recent interest in optimizing composition and synthesis conditions of functional crystals, and the further exploration of new possible candidates for tunable solid-state lasers, has led to significant research on compounds in this family MIMIII(MVIO42 (MI = alkali metal, MIII = Al, In, Sc, Fe, Bi, lanthanide; MVI = Mo, W. The vibrational modes, structure transformation, and Al coordination of crystalline, glassy, and molten states of KAl(MoO42 have been investigated by in-situ high temperature Raman scattering and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR spectroscopy, together with first principles density functional simulation of room temperature Raman spectrum. The results showed that, under the present fast quenching conditions, Al is present predominantly in [AlO6] octahedra in both KAl(MoO42 glass and melt, with the tetrahedrally coordinated Al being minor at approximately 2.7%. The effect of K+, from ordered arrangement in the crystal to random distribution in the melt, on the local chemical environment of Al, was also revealed. The distribution and quantitative analysis of different Al coordination subspecies are final discussed and found to be dependent on the thermal history of the glass samples.

  16. Investigation of high-temperature charge transport mechanism in Al-Gd2O3-Al-based metal-insulator-metal (MIM) structure

    Science.gov (United States)

    Wasiq, M. F.; Mahmood, Khalid; Aen, Faiza; Warsi, Muhammad Farooq; Khan, Muhammad Azhar

    2016-12-01

    In this paper, the charge conduction mechanism at high temperature in Al-Gd2O3 (MIM) structure has been investigated by performing temperature-dependent current-voltage measurements in the temperature range 280-390 K. MIM structure is realized by electron beam evaporation system where thin films of Gd2O3 (40, 60 and 80 nm) and Al metal on both sides of dielectric film were deposited on glass substrate. The possibility of different transport mechanisms has been testified by plotting various graphs. The nonlinear behavior of Ln V versus Ln I and V 1/2 versus Ln V/ I graphs ruled out the possibility of space-charge-limited conduction (SCLC) and Poole-Frenkel mechanism in Al-Gd2O3-Al MIM structure. The straight lines Ln I- V 1/2 graphs at various temperatures confirmed that Schottky emission is the dominant transport mechanism in Al-Gd2O3-Al structure. The calculated values of field barrier lowering coefficient at different measurement temperatures were in good agreement with the theoretical prediction confirming conduction is via Schottky emission. The field-dependent Ln( I/ T 2) versus 1000/ T plots were obeyed a linear relationship according to Schottky emission theory. Furthermore, the dielectric thickness dependence room-temperature current-voltage characteristics of Al-Gd2O3-Al MIM structure were showed strong dependence of current on dielectric film thickness according to Schottky emission theory of conduction current.

  17. Development of a Lower-SWaP, RAD-Tolerant, Thermally Stable High Speed Fiber Optics Network for Harsh Environment Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Phase I objectives and work plan, carried through to completion, will result in the development of a RAD-tolerant, high-speed, multi-channel fiber...

  18. Farinose flavonoids are associated with high freezing tolerance in fairy primrose (Primula malacoides) plants.

    Science.gov (United States)

    Isshiki, Ryutaro; Galis, Ivan; Tanakamaru, Shigemi

    2014-02-01

    The deposition of surface (farinose) flavonoids on aerial parts of some Primula species is a well-documented but poorly understood phenomenon. Here, we show that flavonoid deposition on the leaves and winter buds may contribute strongly to preventing freezing damage in these plants. The ice nucleation temperature of fairy primrose (Primula malacoides) leaves covered with natural flavone was approximately 6 °C lower compared to those that had their flavone artificially removed. Additionally, farinose flavonoids on the leaves reduced subsequent electrolyte leakage (EL) from the cells exposed to freezing temperatures. Interestingly, exogenous application of flavone at 4 mg/g fresh weight to P. malacoides leaves, which had the original flavone mechanically removed, restored freezing tolerance, and diminished EL from the cells to pretreatment values. Our results suggest that farinose flavonoids may function as mediators of freezing tolerance in P. malacoides, and exogenous application of flavone could be used to reduce freezing damage during sudden but predictable frost events in other plant species.

  19. Fluidized-bed denitrification of mining water tolerates high nickel concentrations.

    Science.gov (United States)

    Zou, G; Papirio, S; van Hullebusch, E D; Puhakka, J A

    2015-03-01

    This study revealed that fluidized-bed denitrifying cultures tolerated soluble Ni concentrations up to 500 mg/L at 7-8 and 22°C. From 10 to 40 mg/L of feed Ni, denitrification resulted in complete nitrate and nitrite removal. The concomitant reduction of 30 mg/L of sulfate produced 10 mg/L of sulfide that precipitated nickel, resulting in soluble effluent Ni below 22 mg/L. At this stage, Dechloromonas species were the dominant denitrifying bacteria. From 60 to 500 mg/L of feed Ni, nickel remained in solution due to the inhibition of sulfate reduction. At soluble 60 mg/L of Ni, denitrification was partially inhibited prior to recover after 34 days of enrichment by other Ni-tolerant species (including Delftia, Zoogloea and Azospira) that supported Dechloromonas. Subsequently, the FBR cultures completely removed nitrate even at 500 mg/L of Ni. Visual Minteq speciation model predicted the formation of NiS, NiCO3 and Ni3(PO4)2, whilst only Ni3(PO4)2 was detected by XRD.

  20. Synthesis of high-purity Ti2AlN ceramic by hot pressing

    Institute of Scientific and Technical Information of China (English)

    YAN Ming; CHEN Yan-lin; MEI Bing-chu; ZHU Jiao-qun

    2008-01-01

    High-purity Ti2AlN ceramic was prepared at 1300 ℃ by hot pressing(HP) of Ti/Al/TiN powders in stoichiometric proportion. The sintered product was characterized using X-ray diffraction(XRD) and MDI Jade 5.0 software (Materials Data Inc, Liverpool, CA). Scanning electron microscopy(SEM) and electron probe micro-analysis(EPMA) coupled with energy-dispersive spectroscopy(EDS) were utilized to investigate the morphology characteristics. The results show that Ti2AlN phase is well-developed with a close and lamellar structure. The grains are plate-like with the size of 3-5 μm, thickness of 8-10 μm and elongated dimension. The density of Ti2AlN is measured to be 4.22 g/cm3, which reaches 97.9% of its theory value. The distribution of Ti2AlN grains is homogeneous.

  1. High-precision mass measurements of {sup 25}Al and {sup 30}P at JYFLTRAP

    Energy Technology Data Exchange (ETDEWEB)

    Canete, L.; Kankainen, A.; Eronen, T.; Gorelov, D.; Hakala, J.; Jokinen, A.; Kolhinen, V.S.; Koponen, J.; Moore, I.D.; Reinikainen, J.; Rinta-Antila, S. [University of Jyvaskylae (Finland)

    2016-05-15

    The masses of the astrophysically relevant nuclei {sup 25}Al and {sup 30}P have been measured with a Penning trap for the first time. The mass-excess values for {sup 25}Al (Δ=-8915.962(63) keV) and {sup 30}P (Δ=-20200.854(64) keV) obtained with the JYFLTRAP double Penning trap mass spectrometer are in good agreement with the Atomic Mass Evaluation 2012 values but ∼5-10 times more precise. A high precision is required for calculating resonant proton-capture rates of astrophysically important reactions {sup 25}Al(p,γ){sup 26}Si and {sup 30}P(p,γ){sup 31}S. In this work, Q{sub (p,γ)}=5513.99(13) keV and Q{sub (p,γ)}=6130.64(24) keV were obtained for {sup 25}Al and {sup 30}P, respectively. The effect of the more precise values on the resonant proton-capture rates has been studied. In addition to nuclear astrophysics, the measured Q{sub EC} value of {sup 25}Al, 4276.805(45) keV, is relevant for studies of T=1/2 mirror beta decays which have a potential to be used to test the Conserved Vector Current hypothesis. (orig.)

  2. Fabrication of Highly-Oleophobic and Superhydrophobic Surfaces on Microtextured al Substrates

    Science.gov (United States)

    Liu, Changsong; Zhou, Jigen; Zheng, Dongmei; Wan, Yong; Li, Zhiwen

    2011-06-01

    Theoretical calculations suggest that creating highly-oleophobic surfaces would require a surface energy lower than that of any known materials. In the present work, we demonstrate microtextured Al substrate surfaces with veins-like micro/nanostructures displaying apparent contact angles (CA) greater than 120°, even with nitromethane (surface tension γ1 = 37 mN/m). The Al substrate was microtextured by a chemical solution mixed by zinc nitrate hexahydrate, hexamethyltetramine and a little of hydrofluoric acid. A fluoroalkylsilane (FAS) agent was used to tune the surface wettability. The Al substrates were microtextured by veins-like micro/nanostructures and generating a solid-liquid-vapor composite interface. Combination with FAS modification, the Al surfaces resulted in an oleophobicity with CA for nitromethane was 126.3° (152.7° for diethylene glycol, γ1 = 45.2 mN/m). In addition, the Al surfaces demonstrated a low rolling-off angle with oleophobic behavior is induced mainly by topography, which form a composite surface of air and solid with oil drop sitting partially on air. The results are expected to promote the study on self-cleaning applications, especially in the condition with oil contaminations.

  3. A highly thermoactive and salt-tolerant α-amylase isolated from a pilot-plant biogas reactor.

    Science.gov (United States)

    Jabbour, Dina; Sorger, Anneke; Sahm, Kerstin; Antranikian, Garabed

    2013-04-01

    Aiming at the isolation of novel enzymes from previously uncultured thermophilic microorganisms, a metagenome library was constructed from DNA isolated from a pilot-plant biogas reactor operating at 55 °C. The library was screened for starch-degrading enzymes, and one active clone was found. An open reading frame of 1,461 bp encoding an α-amylase from an uncultured organism was identified. The amy13A gene was cloned in Escherichia coli, resulting in high-level expression of the recombinant amylase. The novel enzyme Amy13A showed the highest sequence identity (75%) to α-amylases from Petrotoga mobilis and Halothermothrix orenii. Amy13A is highly thermoactive, exhibiting optimal activity at 80 °C, and it is also highly salt-tolerant, being active in 25% (w/v) NaCl. Amy13A is one of the few enzymes that tolerate high concentrations of salt and elevated temperatures, making it a potential candidate for starch processing under extreme conditions.

  4. Enhanced thermotolerance and ethanol tolerance in Saccharomyces cerevisiae mutated by high-energy pulse electron beam and protoplast fusion.

    Science.gov (United States)

    Zhang, Min; Xiao, Yu; Zhu, Rongrong; Zhang, Qin; Wang, Shi-Long

    2012-11-01

    To increase thermotolerance and ethanol tolerance in Saccharomyces cerevisiae strain YZ1, the strategies of high-energy pulse electron beam (HEPE) and three rounds of protoplast fusion were explored. The YF31 strain had the characteristics of resistant to high-temperature, high-ethanol tolerance, rapid growth and high yield. The YF31 could grow on plate cultures up to 47 °C, containing 237.5 g L(-1) of ethanol. In particular, the mutant strain YF31 generated 94.2 ± 4.8 g L(-1) ethanol from 200 g glucose L(-1) at 42 °C, which was 2.48 times the production of the wild strain YZ1. Results demonstrated that the variant phenotypes from the strains screening by HEPE irradiation could be used as parent stock for yeast regeneration and the protoplast fusion technology is sufficiently powerful in combining suitable characteristics in a single strain for ethanol fermentation.

  5. Improving high carbon dioxide tolerance and carbon dioxide fixation capability of Chlorella sp. by adaptive laboratory evolution.

    Science.gov (United States)

    Li, Dengjin; Wang, Liang; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2015-06-01

    CO2 capture by microalgae is a promising method to reduce greenhouse gas emissions. It is critical to construct a highly efficient way to obtain a microalgal strain tolerant to high CO2 concentrations with high CO2 fixation capability. In this study, two evolved Chlorella sp. strains, AE10 and AE20 were obtained after 31 cycles of adaptive laboratory evolution (ALE) under 10% and 20% CO2, respectively. Both of them grew rapidly in 30% CO2 and the maximal biomass concentration of AE10 was 3.68±0.08g/L, which was 1.22 and 2.94 times to those of AE20 and original strain, respectively. The chlorophyll contents of AE10 and AE20 were significantly higher than those of the original one under 1-30% CO2. The influences of ALE process on biochemical compositions of Chlorella cells were also investigated. This study proved that ALE was an effective approach to improve high CO2 tolerance of Chlorella sp.

  6. High-brightness beamline for x-ray spectroscopy at the ALS

    Energy Technology Data Exchange (ETDEWEB)

    Perera, R.C.C.; Jones, G. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Lindle, D.W. [Univ. of Nevada, Las Vegas, NV (United States)

    1997-04-01

    Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard x-ray beamline, and its brightness will be an order of magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new {open_quotes}Cowan type{close_quotes} double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12 m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS.

  7. Tolerance to high temperature extremes in an invasive lace bug, Corythucha ciliata (Hemiptera: Tingidae, in subtropical China.

    Directory of Open Access Journals (Sweden)

    Rui-Ting Ju

    Full Text Available Biological invasions are predicted to be more frequent as climate change is increasing its positive impact on the prevalence of invasive exotic species. Success of insect invaders in different temperature zones is closely related to their tolerance to temperature extremes. In this study, we used an exotic lace bug (Corythucha ciliata as the study organism to address the hypotheses that an insect species invading a subtropical zone from temperate regions has a high capacity to survive and adapt to high temperatures, and that its thermal tolerance plays an important role in determining its seasonal abundance and geographic distribution. To test these hypotheses, the effects of heat shock on the survival and reproduction of C. ciliata adults were assessed in the laboratory. Adults were exposed to 26 (control, 35, 37, 39, 41, 43, and 45°C for 2 h, and then were transferred to 26°C. Heat-shock temperatures ranging from 35 to 41°C did not significantly affect survival pattern, longevity, and fecundity of adults, but heat shock at 43 and 45°C significantly reduced these traits. Exposing parent females to heat-shock treatments from 35 to 41°C did not significantly affect the hatching rate of their eggs, survival of the nymphs, and the proportion of female F(1 progeny, while no progeny were produced with treatments of 43 and 45°C. The results indicate that C. ciliata can tolerate high temperatures less than 41°C, which may contribute to its expansion into the lower latitudes in China where its hosts (Platanus trees are widely planted. Our findings have important implications for predicting seasonal abundance and understanding invasion mechanisms of this important urban invader under climate change.

  8. A facile solvent-free Synthesis Route for the Assembly of Highly CO2 Selective and H2S tolerant NiSIFSIX Metal-Organic Framework

    KAUST Repository

    Eddaoudi, Mohamed

    2015-07-06

    The development of materials for CO2 capture with high selectivity and high tolerance to H2S is of prime importance for various industrially relevant gas streams (e.g. natural gas and biogas upgrading as well as pre-combustion capture). Here, we report the successful fabrication of a MOF with combined exceptional CO2 capture properties and H2S tolerance, namely Ni SIFSIX based-MOF using both solvothermal and solvent-free methodologies.

  9. Detecting ALS and ACCase herbicide tolerant accession of Echinochloa oryzoides (Ard.) Fritsch. in rice (Oryza sativa L.) fields

    DEFF Research Database (Denmark)

    Altop, Emine Kaya; Mennan, Husrev; Streibig, Jens Carl

    2014-01-01

    -sodium) and acetyl CoA carboxylase (cyhalofob-butyl) inhibiting herbicides. Comparison of 95% lower confidence intervals of ED90 derived from log-logistic dose-response curves, and twice the recommended field rates of the herbicides showed some, but not distinct separation of susceptible and tolerant accessions. We...

  10. Low Cost Al-Si Casting Alloy As In-Situ Composite for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2000-01-01

    A new aluminum-silicon (Al-Si) alloy has been successfully developed at NASA- Marshall Space Flight Center (MSFC) that has significant improvement in tensile and fatigue strength at elevated temperatures (500 F-700 F). The alloy offers a number of benefits such as light weight, high hardness, low thermal expansion and high surface wear resistance. In hypereutectic form, this alloy is considered as an in-situ Al-Si composite with tensile strength of about 90% higher than the auto industry 390 alloy at 600 F. This composite is very economically produced by using either conventional permanent steel molds or die casting. The projected material cost is less than $0.90 per pound, and automotive components such as pistons can be cast for high production rate using conventional casting techniques with a low and fully accounted cost. Key Words: Metal matrix composites, In-situ composite, aluminum-silicon alloy, hypereutectic alloy, permanent mold casting, die casting.

  11. Control of two-dimensional growth of AlN and high Al-content AlGaN-based MQWs for deep-UV LEDs

    Directory of Open Access Journals (Sweden)

    Weihuang Yang

    2013-05-01

    Full Text Available Dense and atomically flat AlN film with root-mean-square roughness value of 0.32 nm was grown on sapphire substrate at a relatively lower temperature by using a three-step epitaxy technique. On the basis of this AlN template, AlGaN-based multiple quantum wells (MQWs with atomically flat hetero-interfaces were epitaxially grown to suppress nonradiative recombination by introducing In as a surfactant during simultaneous source supply. As a result, single intense- and narrow-peaked photoluminescence was obtained from the MQWs. Finally, the deep ultraviolet light emitting diodes with well-behaved I-V characteristic and strong electroluminescence in the range of 256–312 nm were fabricated successfully.

  12. Warm Spraying of High-Strength Ni-Al-Bronze: Cavitation Characteristics and Property Prediction

    Science.gov (United States)

    Krebs, Sebastian; Kuroda, Seiji; Katanoda, Hiroshi; Gaertner, Frank; Klassen, Thomas; Araki, Hiroshi; Frede, Simon

    2017-01-01

    Bronze materials such as Ni-Al-bronze show exceptional performances against cavitation erosion, due to their high fatigue strength and high strength. These materials are used for ship propellers, pump systems or for applications with alternating stresses. Usually, the respective parts are cast. With the aim to use resources more efficiently and to reduce costs, this study aimed to evaluate opportunities to apply bronze as a coating to critical areas of respective parts. The coatings should have least amounts of pores and non-bonded areas and any contaminations that might act as crack nuclei and contribute to material damages. Processes with low oxidation and high kinetic impacts fulfill these criteria. Especially warm spraying, a nitrogen-cooled HVOF process, with similar impact velocities as cold gas spraying but enhanced process temperature, allows for depositing high-strength Ni-Al-bronze. This study systematically simulates and evaluates the formation and performance of warm-sprayed Ni-Al-bronze coatings for different combustion pressures and nitrogen flow rates. Substrate preheating was used to improve coating adhesion for lower spray parameter sets. Furthermore, this study introduces an energy-based concept to compare spray parameter sets and to predict coating properties. Coatings with low porosities and high mechanical strengths are obtained, allowing for a cavitation resistance similar to bulk material.

  13. Synthesis of high Al content Al{sub x}Ga{sub 1−x}N ternary films by pulsed laser co-ablation of GaAs and Al targets assisted by nitrogen plasma

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Hua; You, Qinghu [Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); Hu, Zhigao; Guo, Shuang [Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China); Yang, Xu; Sun, Jian; Xu, Ning [Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); Wu, Jiada, E-mail: jdwu@fudan.edu.cn [Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China)

    2014-12-15

    Highlights: • Al{sub x}Ga{sub 1−x}N films were synthesized by co-ablation of an Al target and a GaAs target. • Nitrogen plasma was used to assist the synthesis of Al{sub x}Ga{sub 1−x}N ternary films. • The Al{sub x}Ga{sub 1−x}N films are slightly rich in N with an Al content above 0.6. • The Al{sub x}Ga{sub 1−x}N films are hexagonal wurtzite in crystal structure. • The Al{sub x}Ga{sub 1−x}N films have an absorption edge of 260 nm and a band gap of 4.7 eV. - Abstract: We present the synthesis of Al{sub x}Ga{sub 1−x}N ternary films by pulsed laser co-ablation of a polycrystalline GaAs target and a metallic Al target in the environment of nitrogen plasma which provides nitrogen for the films and assists the formation of nitride films. Field emission scanning electron microscopy exposes the smooth surface appearance and dense film structure. X-ray diffraction, Fourier-transform infrared spectroscopy and Raman scattering spectroscopy reveal the hexagonal wurtzite structure. Optical characterization shows high optical transmittance with an absorption edge of about 260 nm and a band gap of 4.7 eV. Compositional analysis gives the Al content of about 0.6. The structure and optical properties of the Al{sub x}Ga{sub 1−x}N films are compared with those of binary GaN and AlN films synthesized by ablating GaAs or Al target with the same nitrogen plasma assistance.

  14. Influence of High Temperature Creep upon the Structure of ß-NiAl and ß-NiAl(Fe) Single Crystals

    OpenAIRE

    Zhang, Hui

    2002-01-01

    The principal aim of this thesis is to characterise quantitatively the influence of high temperature creep upon the structure of ß-NiAl and ß-NiAl(Fe) single crystals. A non-destructive procedure is established following the classic line of X-ray structure analysis, namely controlling the chemical composition with the electron probe microanalysis, determining the unit cell contents from the combined lattice parameter and mass density measurements, and refining the structure parameters accordi...

  15. 常压及高压凝固Al-Mg及Al-Mg-Zn合金中Al相的固溶体结构%Solid solution structure of Al phase in Al-Mg and Al-Mg-Zn alloys solidifying under normal pressure and high pressure

    Institute of Scientific and Technical Information of China (English)

    王振玲; 张涛; 李莉; 周月波; 王宏伟; 魏尊杰

    2012-01-01

    采用X射线衍射仪、能谱仪和透射电镜分别对Al-9.6%Mg合金、Al- 11Mg-4.5Zn合金和Al- 17Zn- 1.5Mg合金常压及6 GPa高压凝固后Al相的固溶体结构进行研究.结果表明:6GPa高压凝固后,Al-9.6%Mg合金中Mg在Al相中的固溶度显著增大:在Al-11Mg-4.5Zn合金和Al- 17Zn- 1.5Mg合金中,Mg、Zn溶质在Al相中的固溶度均增大,但Zn比Mg固溶的比例要大得多.在常压凝固条件下,与纯铝相比,3种合金中Al相的晶格常数均增大.与常压凝固相比,高压凝固Al-9.6Mg合金和Al-11Mg-4.5Zn中Al相晶格常数分别增大了1.178%和0.220%;在Al- 17Zn- 1.5Mg合金中,Al相晶格常数变化很小.此外,在Al-Mg-Zn合金中,原子半径较大的Mg固溶到Al相中,导致其晶格常数增大,原子半径较小的Zn固溶到Al相中,导致其晶格常数减小,且高压凝固后,溶质的原子半径越小,在Al相中固溶的比例越大.%The solid solution structures of Al phases in Al-9.6%Mg, Al-llMg-4.5Zn andAl-17Zn-1.5Mg alloys solidified under normal pressure and high pressure were investigated using XRD, EDS and TEM. The results show that the solid solubility of Mg in Al phase in Al-9.6%Mg alloy increases remarkably, and those of Mg and Zn in Al phase in Al-llMg-4.5Zn and Al-17Zn-1.5Mg alloys increase, however, the proportion of Zn saturating in Al phase is much more than that of Mg. Under the condition of normal pressure solidification, the lattice constants of Al phases in three alloys have an increment comparing with that of pure Al. In contrast to normal pressure solidification, the lattice constants of Al phases in Al-9.6Mg alloy and AI-llMg-4.5Zn alloy solidifying at 6 GPa high pressure increase up to 1.178% and 0.220%, respectively. And the lattice constant of Al phase in AI-17Zn-1.5Mg alloy changes little. Furthermore, Mg with larger atomic radius saturating in Al phase leads to the increment of the lattice constant in Al-Mg-Zn alloy, and that of Zn with smaller atomic radium causes

  16. The Al Effects of Co-Free and V-Containing High-Entropy Alloys

    Directory of Open Access Journals (Sweden)

    Songqin Xia

    2017-01-01

    Full Text Available In this study, five-component high-entropy alloys (HEAs AlxCrFeNiV (where x denotes the molar ratio, x = 0, 0.1, 0.3, 0.5, 0.75, 1, and 1.5 were prepared using an arc-melting furnace. The effects of the addition of the Al on the crystal structures were investigated using X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. Also, two non-equiatomic ratio HEAs, AlxCrFeNiV (x = 0.3, and 0.5, were systematically studied through the use of various characterization methods in the as-cast state. The Al0.3CrFeNiV alloy displayed typical duplex body-centered cubic (BCC structures, including disordered BCC (A2, and NiAl-type ordered BCC (B2 phases. Meanwhile, in regard to the Al0.5CrFeNiV alloy, this alloy was found to contain an unknown phase which was enriched in Cr and V, as well as the coherent A2/B2 phases. Both of these alloys displayed very high yield and fracture strengths. However, their compression fracture strains were approximately 10%. Also, the fracture surfaces showed mainly cleavage fracture modes.

  17. Synthesis of ZrAlN coatings with thermal stability at high temperature

    Institute of Scientific and Technical Information of China (English)

    LI; Dejun

    2006-01-01

    Dry machining will result in elevated temperatures at the tool surface (800-1000℃). So, coating materials that can provide protection for cutting tools at these temperatures are of great technological interests. ZrAlN coating is proposed to possess high-temperature stable structural and mechanical properties due to the addition of the alloying element. ZrAlN coatings were grown using a dc reactive magnetron sputtering. The XRD and nano indenter were employed to investigate the effects of reaction gas partial pressure and substrate bias on structural and mechanical properties, as well as high-temperature stability. The ZrAlN coating, when deposited under optimum conditions (-37 V substrate bias and 2×10-5 Pa N2 partial pressure), showed smooth surface with thermal stable hardness. Its internal stress was relaxed from 2.2 to 0.7 GPa after annealing. Formation of Al2O3 and ZrO2 crystalline phases should be related to thermal stability of the coatings.

  18. Nanoscale TiO₂-coated LPGs as radiation-tolerant humidity sensors for high-energy physics applications.

    Science.gov (United States)

    Consales, Marco; Berruti, Gaia; Borriello, Anna; Giordano, Michele; Buontempo, Salvatore; Breglio, Giovanni; Makovec, Alajos; Petagna, Paolo; Cusano, Andrea

    2014-07-15

    This Letter deals with a feasibility analysis for the development of radiation-tolerant fiber-optic humidity sensors based on long-period grating (LPG) technology to be applied in high-energy physics (HEP) experiments currently running at the European Organization for Nuclear Research (CERN). In particular, here we propose a high-sensitivity LPG sensor coated with a finely tuned titanium dioxide (TiO₂) thin layer (~100 nm thick) through the solgel deposition method. Relative humidity (RH) monitoring in the range 0%-75% and at four different temperatures (in the range -10°C-25°C) was carried out to assess sensor performance in real operative conditions required in typical experiments running at CERN. Experimental results demonstrate the very high RH sensitivities of the proposed device (up to 1.4 nm/% RH in correspondence to very low humidity levels), which turned out to be from one to three orders of magnitude higher than those exhibited by fiber Bragg grating sensors coated with micrometer-thin polyimide overlays. The radiation tolerance capability of the TiO₂-coated LPG sensor is also investigated by comparing the sensing performance before and after its exposure to a 1 Mrad dose of γ-ionizing radiation. Overall, the results collected demonstrate the strong potential of the proposed technology with regard to its future exploitation in HEP applications as a robust and valid alternative to the commercial (polymer-based) hygrometers currently used.

  19. Triglycerides to High-Density Lipoprotein Cholesterol Ratio Can Predict Impaired Glucose Tolerance in Young Women with Polycystic Ovary Syndrome.

    Science.gov (United States)

    Song, Do Kyeong; Lee, Hyejin; Sung, Yeon Ah; Oh, Jee Young

    2016-11-01

    The triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio could be related to insulin resistance (IR). We previously reported that Korean women with polycystic ovary syndrome (PCOS) had a high prevalence of impaired glucose tolerance (IGT). We aimed to determine the cutoff value of the TG/HDL-C ratio for predicting IR and to examine whether the TG/HDL-C ratio is useful for identifying individuals at risk of IGT in young Korean women with PCOS. We recruited 450 women with PCOS (24±5 yrs) and performed a 75-g oral glucose tolerance test (OGTT). IR was assessed by a homeostasis model assessment index over that of the 95th percentile of regular-cycling women who served as the controls (n=450, 24±4 yrs). The cutoff value of the TG/HDL-C ratio for predicting IR was 2.5 in women with PCOS. Among the women with PCOS who had normal fasting glucose (NFG), the prevalence of IGT was significantly higher in the women with PCOS who had a high TG/HDL-C ratio compared with those with a low TG/HDL-C ratio (15.6% vs. 5.6%, p2.5 are recommended to be administered an OGTT to detect IGT even if they have NFG.

  20. Glycinebetaine enhances the tolerance of tomato plants to high temperature during germination of seeds and growth of seedlings.

    Science.gov (United States)

    Li, Shufen; Li, Feng; Wang, Jianwei; Zhang, Wen; Meng, Qingwei; Chen, Tony H H; Murata, Norio; Yang, Xinghong

    2011-11-01

    Tomato (Lycopersicon esculentum cv. 'Moneymaker') was transformed with a codA gene, from Arthrobacter globiformis, for choline oxidase that had been modified to allow targeting to both chloroplasts and the cytosol. Glycinebetaine (GB) accumulated in seeds of transformed plants up to 1 µmol g(-1) dry weight (DW), while no detectable GB was found in wild-type (WT) seeds. The codA-transgenic seeds germinated faster and at higher frequency than WT seeds with high temperature treatment. After heat stress, levels of expression of a mitochondrial small heat-shock protein (MT-sHSP), heat-shock protein 70 (HSP70) and heat-shock cognate 70 (HSC70) were higher in transgenic seeds than in WT seeds during heat stress, and the accumulation of HSP70 was more prominent in codA-transgenic seeds than in WT seeds. Addition of GB to the germination medium or imbibition of seeds in a solution of GB enhanced the tolerance of WT seeds to high temperatures. WT seeds treated with exogenous GB also expressed heat-shock genes at elevated levels and accumulated more HSP70 than controls. Our results suggest that GB, either applied exogenously or accumulated in vivo in codA-transgenic seeds, enhanced the expression of heat-shock genes in and improved the tolerance to high temperature of tomato seeds during germination.

  1. The New Kilogram Definition and its Implications for High-Precision Mass Tolerance Classes.

    Science.gov (United States)

    Abbott, Patrick J; Kubarych, Zeina J

    2013-01-01

    The SI unit of mass, the kilogram, is the only remaining artifact definition in the seven fundamental units of the SI system. It will be redefined in terms of the Planck constant as soon as certain experimental conditions, based on recommendations of the Consultative Committee for Mass and Related Quantities (CCM) are met. To better reflect reality, the redefinition will likely be accompanied by an increase in the uncertainties that National Metrology Institutes (NMIs) pass on to customers via artifact dissemination, which could have an impact on the reference standards that are used by secondary calibration laboratories if certain weight tolerances are adopted for use. This paper will compare the legal metrology requirements for precision mass calibration laboratories after the kilogram is redefined with the current capabilities based on the international prototype kilogram (IPK) realization of the kilogram.

  2. Radiation tolerance study of a commercial 65 nm CMOS technology for high energy physics applications

    Science.gov (United States)

    Ding, Lili; Gerardin, Simone; Bagatin, Marta; Bisello, Dario; Mattiazzo, Serena; Paccagnella, Alessandro

    2016-09-01

    This paper reports the radiation tolerance study of a commercial 65 nm technology, which is a strong candidate for the Large Hadron Collider applications. After exposure to 3 MeV protons till 1 Grad dose, the 65 nm CMOS transistors, especially the pMOSFETs, showed severe long-term degradation mainly in the saturation drain currents. There were some differences between the degradation levels in the nMOSFETs and the pMOSFETs, which were likely attributed to the positive charges trapped in the gate spacers. After exposure to heavy ions till multiple strikes, the pMOSFETs did not show any sudden loss of drain currents, the degradations in the characteristics were negligible.

  3. Metasurface-based broadband hologram with high tolerance to fabrication errors.

    Science.gov (United States)

    Zhang, Xiaohu; Jin, Jinjin; Wang, Yanqin; Pu, Mingbo; Li, Xiong; Zhao, Zeyu; Gao, Ping; Wang, Changtao; Luo, Xiangang

    2016-01-01

    With new degrees of freedom to achieve full control of the optical wavefront, metasurfaces could overcome the fabrication embarrassment faced by the metamaterials. In this paper, a broadband hologram using metasurface consisting of elongated nanoapertures array with different orientations has been experimentally demonstrated. Owing to broadband characteristic of the polarization-dependent scattering, the performance is verified at working wavelength ranging from 405 nm to 914 nm. Furthermore, the tolerance to the fabrication errors, which include the length and width of the elongated aperture, the shape deformation and the phase noise, has been theoretically investigated to be as large as 10% relative to the original hologram. We believe the method proposed here is promising in emerging applications such as holographic display, optical information processing and lithography technology etc.

  4. Increased stress tolerance of matured pig oocytes after high hydrostatic presure

    DEFF Research Database (Denmark)

    Pribenszky, Cs; Du, Y; Molnár, M;

    2008-01-01

    treated with different pressure impulses in the range of 20-80 MPa (200-800 times greater than atmospheric pressure) for 30-120 min at 24 °C. For parthenogenetic activation a single dc of 12.5 kV/cm was used, to test shock tolerance of the treated vs. control oocytes and also compare their developmental...... electric (single dc of 1.25 kV/cm) and chemical treatment after warming. According to our investigations performed with a total of 1980 oocytes and 3-5 replicates, pressure treatment increased cleavage and blastocyst rates after activation and cleavage rates after vitrification followed by activation. Our...... results indicate that the sublethal pressure treatment may induce specific responses in oocytes increasing their resistance and developmental competence. The mechanism that may lie behind the observations is the sublethal stress-induced post-transcriptional activation of shock proteins in the oocytes...

  5. Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet.

    Science.gov (United States)

    Snoussi, Chahira; Ducroc, Robert; Hamdaoui, Mohamed Hédi; Dhaouadi, Karima; Abaidi, Houda; Cluzeaud, Francoise; Nazaret, Corinne; Le Gall, Maude; Bado, André

    2014-05-01

    Green tea containing polyphenols exerts antidiabetic and antiobesity effects, but the mechanisms involved are not fully understood. In this study, we first analyzed and compared polyphenol compounds [epigallocatechin gallate (EGCG), epigallocatechin (EGC)] in decoction of green tea leaves versus usual green tea extracts. Second, the effects of acute (30 min) or chronic (6 weeks) oral administration of green tea decoction (GTD) on intestinal glucose absorption were studied in vitro in Ussing chamber, ex vivo using isolated jejunal loops and in vivo through glucose tolerance tests. Finally, we explore in rat model fed normal or high-fat diet the effects of GTD on body weight, blood parameters and on the relative expression of glucose transporters SGLT-1, GLUT2 and GLUT4. GTD cooked for 15 min contained the highest amounts of phenolic compounds. In fasted rats, acute administration of GTD inhibited SGLT-1 activity, increased GLUT2 activity and improved glucose tolerance. Similarly to GTD, acute administration of synthetic phenolic compounds (2/3 EGCG+1/3 EGC) inhibited SGLT-1 activity. Chronic administration of GTD in rat fed high-fat diet reduced body weight gain, circulating triglycerides and cholesterol and improved glucose tolerance. GTD-treated rats for 6 weeks display significantly reduced SGLT-1 and increased GLUT2 mRNA levels in the jejunum mucosa. Moreover, adipose tissue GLUT4 mRNA levels were increased. These results indicate that GTD, a traditional beverage rich in EGCG and EGC reduces intestinal SGLT-1/GLUT2 ratio, a hallmark of regulation of glucose absorption in enterocyte, and enhances adipose GLUT4 providing new insights in its possible role in the control of glucose homeostasis. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Safety and tolerability of ramipril 10 mg in patients at high risk of cardiovascular events: an observational study.

    Science.gov (United States)

    Hathial, Manish

    2008-07-01

    To assess the safety and tolerability of ramipril 10 mg in patients at high risk of cardiovascular (CV) events by observing the levels of blood pressure (BP) and by recording the incidence of cough in these patients, a study was conducted in a total of 1048 patients who participated in the registry. Eligible patients in this prospective, observational, longitudinal, multicentre registry included all normotensives--including treated hypertensives--with BP risk reduction and had been prescribed by the treating physician. The primary outcome was the effect on BP at 8 weeks, and the secondary outcome was the incidence of cough at 8 weeks. Ramipril was initiated at 2.5 mg once daily (OD) for a week, followed by 5 mg OD for 3 weeks and was then increased to 10 mg OD. Data was analysed using ANOVA and Chi-square test. A total of 1,048 patients participated in this registry; 868 (82.82%) continued with the treatment till the end of the registry (ie, 8 weeks). At baseline, systolic BP was 130.10 +/- 5.38 mm Hg, while diastolic BP was 81.07 +/- 4.36 mm Hg. At 8 weeks, these values changed non-significantly to 123.41 +/- 6.33 mm Hg and 79.03 +/- 4.84 mm Hg, respectively. At week 1, 41 patients had cough, which increased non-significantly to 58 by week 8. Only 6 patients complained of severe cough at week 8, which did not lead to treatment discontinuation. Tolerability of the treatment was assessed to be 'excellent' or 'good' by 63.3% patients and 67% physicians. Treatment with ramipril 10 mg daily in patients with high risk of CV events and normal/ controlled BP produced neither a significant fall in BP nor significant adverse events in real-world clinical practice and was well tolerated.

  7. Characteristics of MCrAlY coatings sprayed by high velocity oxygen-fuel spraying system

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Y.; Saitoh, M.; Tamura, M.

    2000-01-01

    High velocity oxygen-fuel (HVOF) spraying system in open air has been established for producing the coatings that are extremely clean and dense. It is thought that the HVOF sprayed MCrAlY (M is Fe, Ni and/or Co) coatings can be applied to provide resistance against oxidation and corrosion to the hot parts of gas turbines. Also, it is well known that the thicker coating can be sprayed in comparison with any other thermal spraying systems due to improved residual stresses. However, thermal and mechanical properties of HVOF coatings have not been clarified. Especially, the characteristics of residual stress, that are the most important property from the view point of production technique, have not been made clear. In this paper, the mechanical properties of HVOF sprayed MCrAlY coatings were measured in both the case of as-sprayed and heat-treated coatings in comparison with a vacuum plasma sprayed MCrAlY coatings. It was confirmed that the mechanical properties of HVOF sprayed MCrAlY coatings could be improved by a diffusion heat treatment to equate the vacuum plasma sprayed MCrAlY coatings. Also, the residual stress characteristics were analyzed using a deflection measurement technique and a X-ray technique. The residual stress of HVOF coating was reduced by the shot-peening effect comparable to that of a plasma spray system in open air. This phenomena could be explained by the reason that the HVOF sprayed MCrAlY coating was built up by poorly melted particles.

  8. Electrical properties of Al-In-Sn alloys directionally solidified in high and low gravitational fields

    Science.gov (United States)

    Wu, M. K.; Ashburn, J. R.; Kaukler, W. F.; Curreri, P. A.

    1987-01-01

    The Al-In-Sn alloys were directionally solidified in the NASA KC-135 aircraft which flies a series of parabolas to generate high (high-g) and low (low-g) gravity forces parallel to the longitudinal growth axis. Thus, for a given sample, successive sections can be identified which were solidified in high-g and low-g. Measurements of the electronic properties of the samples reveal that: the resistivity of the low-g sections is larger (about a factor of 10) than that of the high-g sections; the low-g sections behave conductively like a semi-metal, while the high-g sections are essentially metallic; and both high-g and low-g sections are superconducting but the superconducting transition temperature of the low-g sections is 1 K higher than that of the high-g sections.

  9. Electrical properties of Al-In-Sn alloys directionally solidified in high and low gravitational fields

    Science.gov (United States)

    Wu, M. K.; Ashburn, J. R.; Curreri, P. A.; Kaukler, W. F.

    1987-08-01

    Al-ln-Sn alloys have been directionally solidified in the NASA KC-135 aircraft which flies a series of parabolas to generate high (high-g) and low gravity (low-g) forces parallel to the longitudinal growth axis. Thus, for a given sample successive sections can be identified which were solidified in high-g and in low-g. Measurements on the electronic properties of the samples reveal that (1) the resistivity of the low-g sections is larger (about a factor of 10) than that of the high-g sections; (2) the low-g sections behave conductively like a semi-metal, while the high-g sections are essentially metallic; and (3) both high-g and low-g sections are superconducting but the superconducting transition temperature of the low-g sections is 1 K higher than that of the high-g sections.

  10. Synthesis and high-pressure electrical resistivity studies of Ti{sub 3}Al

    Energy Technology Data Exchange (ETDEWEB)

    Vennila, R. Selva [Department of Physics, Anna University, Chennai 600025 (India)]. E-mail: rsvennila@yahoo.co.in; Porchelvi, E. Elamurugu [Department of Physics, Anna University, Chennai 600025 (India); Joy, K.M. Freny [Department of Physics, Anna University, Chennai 600025 (India); Arun, T.K. Jaya [Department of Physics, Anna University, Chennai 600025 (India); Jaya, N. Victor [Department of Physics, Anna University, Chennai 600025 (India)

    2005-04-19

    Titanium aluminide (Ti{sub 3}Al) has been synthesized by a powder metallurgical method. X-ray diffraction studies show the formation of a single phase with hexagonal structure. Electrical resistivity studies were carried out by a four-probe technique both at high pressure and high temperature using a Bridgman Opposed Anvil High Pressure Device (OAHPD). The sample was studied up to a pressure and temperature of 10 GPa and 250 deg. C, respectively. The electrical resistivity is found to decrease with increasing pressure. The temperature effect causes an upward shift in the electrical resistivity in the range of pressure considered.

  11. Low-ohmic-contact-resistance V-based electrode for n-type AlGaN with high AlN molar fraction

    Science.gov (United States)

    Mori, Kazuki; Takeda, Kunihiro; Kusafuka, Toshiki; Iwaya, Motoaki; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu; Amano, Hiroshi

    2016-05-01

    We investigated a V-based electrode for the realization of low ohmic-contact resistivity in n-type AlGaN with a high AlN molar fraction characterized by the circular transmission line model. The contact resistivity of n-type Al0.62Ga0.38N prepared using the V/Al/Ni/Au electrode reached 1.13 × 10-6 Ω cm2. Using this electrode, we also demonstrated the fabrication of UV light-emitting diodes (LEDs) with an emission wavelength of approximately 300 nm. An operating voltage of LED prepared using a V/Al/Ni/Au electrode was 1.6 V lower at 100 mA current injection than that prepared using a Ti/Al/Ti/Au electrode, with a specific contact resistance of approximately 2.36 × 10-4 Ω cm2 for n-type Al0.62Ga0.38N.

  12. High resolution electron microscopy study of a high Cu variant of Weldalite (tm) 049 and a high strength Al-Cu-Ag-Mg-Zr alloy

    Science.gov (United States)

    Herring, R. A.; Gayle, Frank W.; Pickens, Joseph R.

    1991-01-01

    Weldalite (trademark) 049 is an Al-Cu-Li-Ag-Mg alloy that is strengthened in artificially aged tempers primarily by very thin plate-like precipitates lying on the set of (111) matrix planes. This precipitate might be expected to be the T(sub 1) phase, Al2CuLi, which has been observed in Al-Cu-Li alloys. However, in several ways this precipitate is similar to the omega phase which also appears as the set of (111) planes plates and is found in Al-Cu-Ag-Mg alloys. The study was undertaken to identify the set of (111) planes precipitate or precipitates in Weldalite (trademark) 049 in the T8 (stretched and artificially aged) temper, and to determine whether T(sub 1), omega, or some other phase is primarily responsible for the high strength (i.e., 700 MPa tensile strength) in this Al-Cu-Li-Ag-Mg alloy.

  13. High-power high-efficiency GaAlAs superluminescent diodes with an internal absorber for lasing suppression

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, N.S.K.; Lau, K.Y.; Bar-Chaim, N.

    1989-04-01

    The operation principles of a high-power high-efficiency GaAlAs superluminescent diode based on an internal absorber for lasing suppression will be described. The absorber is based on an unpumped/reverse biased section in the device, and the superluminescent diode characteristic depends heavily on the bias condition on the absorber section. The very high efficiency of the device arises from the strong waveguiding effect of the buried heterostructure. A theory which accurately describes the various device characteristics will be described.

  14. Genetic Approaches to Develop Salt Tolerant Germplasm

    KAUST Repository

    Tester, Mark A.

    2015-08-19

    Forty percent of the world\\'s food is produced under irrigation, and this is directly threatened by over-exploitation and changes in the global environment. One way to address this threat is to develop systems for increasing our ability to use lower quality water, in particular saline water. Low cost partial desalination of brackish water, use of saline water for cooling and increases in the salinity tolerance of crops can all contribute to the development of this new agricultural system. In this talk, the focus will be on the use of forward genetic approaches for discovery of genes related to salinity tolerance in barley and tomatoes. Rather than studying salinity tolerance as a trait in itself, we dissect salinity tolerance into a series of components that are hypothesised to contribute to overall salinity tolerance (following the paradigm of Munns & Tester, 2008). For example, one significant component of tolerance of most crop plants to moderate soil salinity is due to the ability to maintain low concentrations of Na+ in the leaves, and much analysis of this aspect has been done (e.g. Roy et al., 2013, 2014). A major site for the control of shoot Na+ accumulation is at the plasma membrane of the mature stele of the root. Alleles of HKT, a major gene underlying this transport process have been characterized and, in work led by Dr Rana Munns (CSIRO), have now been introgressed into commercial durum wheat and led to significantly increased yields in saline field conditions (Munns et al., 2012). The genotyping of mapping populations is now highly efficient. However, the ability to quantitatively phenotype these populations is now commonly limiting forward progress in plant science. The increasing power of digital imaging and computational technologies offers the opportunity to relieve this phenotyping bottleneck. The Plant Accelerator is a 4500m2 growth facility that provides non-destructive phenotyping of large populations of plants (http

  15. Magnesium and Calcium Aluminate Liquids: In Situ High-Temperature 27Al NMR Spectroscopy.

    Science.gov (United States)

    Poe, B T; McMillan, P F; Coté, B; Massiot, D; Coutures, J P

    1993-02-05

    The use of high-temperature nuclear magnetic resonance (NMR) spectroscopy provides a means of investigating the structure of refractory aluminate liquids at temperatures up to 2500 K. Time-averaged structural information indicates that the average aluminum coordination for magnesium aluminate (MgAl(2)O(4)) liquid is slightly greater than for calcium aluminate (CaAl(2)O(4)) liquid and that in both liquids it is close to four. Ion dynamics simulations for these liquids suggest the presence of four-, five-, and six-coordinated aluminate species, in agreement with NMR experiments on fast-quenched glasses. These species undergo rapid chemical exchange in the high-temperature liquids, which is evidenced by a single Lorentzian NMR line.

  16. Compressibility anomaly in the superconducting material Nb{sub 3}Al under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Z.H., E-mail: zhenhaiuy@gmail.com [Department of Physics, Harbin Institute of Technology, Harbin 150080 (China); XSD, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Li, C.Y. [Department of Physics, Harbin Institute of Technology, Harbin 150080 (China); Photon Sciences Directorate, Brookhaven National Laboratory, Upton, NY 11973 (United States); Liu, H.Z. [Natural Science Research Center, Harbin Institute of Technology, Harbin 150080 (China)

    2012-09-01

    Nb{sub 3}Al, which is widely used in high field magnets, was studied under a range of pressures up to 39.5 GPa using diamond anvil cell. The Nb{sub 3}Al superconductor is structurally stable up to the highest pressure of the present investigation from previous reports. However, an anomaly of the compressibility beyond 19.2 GPa was detected in the pressure versus volume plot. The curve of volume versus pressure shows the existence of a plateau around 18.0 GPa as seen in several other highly correlated electrons systems, The observed pressure-induced isostructural phase transition was accomplished with a volume inclination without any symmetrical change (space group, Wyckoff position). The physical mechanism behind this isostructural phase transition is the interesting issue for further studies.

  17. Fe-Al2O3 nanocomposites prepared by high-energy ball milling

    DEFF Research Database (Denmark)

    Linderoth, Søren; Pedersen, M.S.

    1994-01-01

    Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ball milling, exhibit coercivities which are enhanced by about two orders of magnitude with respect to the bulk value. The degree of enhancement depends on the volume fraction (x(upsilon)) of Fe, with a maximum for x(upsilon) alm......Nanocomposites of alpha-Fe and alpha-Al2O3, prepared by high-energy ball milling, exhibit coercivities which are enhanced by about two orders of magnitude with respect to the bulk value. The degree of enhancement depends on the volume fraction (x(upsilon)) of Fe, with a maximum for x......(upsilon) almost-equal-to 0.25. The effect is ascribed to the production of single-domain magnetic grains. Mossbauer spectroscopy reveals the presence of iron oxide phases which could not be seen by x-ray and electron diffraction measurements....

  18. Post-CMOS compatible high-throughput fabrication of AlN-based piezoelectric microcantilevers

    Science.gov (United States)

    Pérez-Campos, A.; Iriarte, G. F.; Hernando-Garcia, J.; Calle, F.

    2015-02-01

    A post-complementary metal oxide semiconductor (CMOS) compatible microfabrication process of piezoelectric cantilevers has been developed. The fabrication process is suitable for standard silicon technology and provides low-cost and high-throughput manufacturing. This work reports design, fabrication and characterization of piezoelectric cantilevers based on aluminum nitride (AlN) thin films synthesized at room temperature. The proposed microcantilever system is a sandwich structure composed of chromium (Cr) electrodes and a sputtered AlN film. The key issue for cantilever fabrication is the growth at room temperature of the AlN layer by reactive sputtering, making possible the innovative compatibility of piezoelectric MEMS devices with CMOS circuits already processed. AlN and Cr have been etched by inductively coupled plasma (ICP) dry etching using a BCl3-Cl2-Ar plasma chemistry. As part of the novelty of the post-CMOS micromachining process presented here, a silicon Si (1 0 0) wafer has been used as substrate as well as the sacrificial layer used to release the microcantilevers. In order to achieve this, the Si surface underneath the structure has been wet etched using an HNA (hydrofluoric acid + nitric acid + acetic acid) based solution. X-ray diffraction (XRD) characterization indicated the high crystalline quality of the AlN film. An atomic force microscope (AFM) has been used to determine the Cr electrode surface roughness. The morphology of the fabricated devices has been studied by scanning electron microscope (SEM). The cantilevers have been piezoelectrically actuated and their out-of-plane vibration modes were detected by vibrometry.

  19. I Am Aware of My Inconsistencies but Can Tolerate Them: The Effect of High Quality Listening on Speakers' Attitude Ambivalence.

    Science.gov (United States)

    Itzchakov, Guy; Kluger, Avraham N; Castro, Dotan R

    2016-11-16

    We examined how listeners characterized by empathy and a non-judgmental approach affect speakers' attitude structure. We hypothesized that high quality listening decreases speakers' social anxiety, which in turn reduces defensive processing. This reduction in defensive processing was hypothesized to result in an awareness of contradictions (increased objective-attitude ambivalence), and decreased attitude extremity. Moreover, we hypothesized that experiencing high quality listening would enable speakers to tolerate contradictory responses, such that listening would attenuate the association between objective- and subjective-attitude ambivalence. We obtained consistent support for our hypotheses across four laboratory experiments that manipulated listening experience in different ways on a range of attitude topics. The effects of listening on objective-attitude ambivalence were stronger for higher dispositional social anxiety and initial objective-attitude ambivalence (Study 4). Overall, the results suggest that speakers' attitude structure can be changed by a heretofore unexplored interpersonal variable: merely providing high quality listening.

  20. High Pressure Form AlOOH and its Relation to Stishovite and Brucite

    Science.gov (United States)

    Kudoh, Y.; Kuribayashi, T.; Suzuki, A.; Ohtani, E.; Kamada, T.

    2001-12-01

    The specimen used in this study was a single crystal of δ -AlOOH synthesized by Suzuki et al. (2000) using a multi-anvil apparatus at conditions of 1000° C and 21 GPa . A set of X-ray diffraction intensities up to sinθ /λ =0.80 Å-1 were measured with a single crystal of 83x35x24 μ m using MoKα radiation (50 kV, 40mA). Al:Mg:Si ratio was measured by EDS with the same crystal used in the X-ray diffraction intensity measurement. EDS analysis showed a Al:Mg:Si ratio 0.84:0.07:0.09, yielding the chemical formula (Al0.84Mg0.07Si0.09)H0.98O2. Crystallographic data for δ -AlOOH obtained are; Orthorhombic, a=4.2060(6) Å, b=4.6975(8) Å, c=2.8327(4) Å, V=55.97(1) Å3, Z=2, Dcalc=3.553 g/cm3. For the space group of δ -AlOOH, Suzuki et al. (2000) reported P21nm from powder X-ray data but the systematic absence of reflections with h+l odd for h0l and k+l odd for 0kl observed in the present work indicated possible space group Pnn2 or Pnnm. The N(Z) test for a center of symmetry indicated an acentric space group. The non-centrosymmetric space group Pnn2 was therefore employed and was confirmed by the structural refinement. The agreement factors for 109 independent reflections (Io>3.0σ Io) were R=3.6% and Rw=6.3% with anisotropic temperature factors. The result of structural analysis showed 5 possible sites for H with O-H- - -O distances of 2.511 Å, 2.553 Å, 2.705 Å, 2.744 Å and 2.834 Å, indicating that the structure is affordable for various amount of H with substituting Al by Mg. The partial occupancy of Mg and Si atoms at Al site suggests the possibility of limited solid solution among δ -AlOOH, stishovite,SiO2 and hypothetical rutile-structured Mg(OH)2. The hypothetical rutile-structured Mg(OH)2 might be a possible candidate for high pressure form of brucite. By the extraporation of the unit cell volumes of δ -AlOOH and stishovite,SiO2, the unit cell volume of the hypothetical rutile-structured Mg(OH)2 is estimated to be V=61.5 A3, giving the density 3.149 g

  1. Surface morphology of Al0.3Ga0.7N/Al2O3-high electron mobility transistor structure.

    Science.gov (United States)

    Cörekçi, S; Usanmaz, D; Tekeli, Z; Cakmak, M; Ozçelik, S; Ozbay, E

    2008-02-01

    We present surface properties of buffer films (AIN and GaN) and Al0.3Gao.zN/Al2O3-High Electron Mobility Transistor (HEMT) structures with/without AIN interlayer grown on High Temperature (HT)-AIN buffer/Al2O3 substrate and Al2O3 substrate. We have found that the GaN surface morphology is step-flow in character and the density of dislocations was about 10(8)-10(9) cm(-2). The AFM measurements also exhibited that the presence of atomic steps with large lateral step dimension and the surface of samples was smooth. The lateral step sizes are in the range of 100-250 nm. The typical rms values of HEMT structures were found as 0.27, 0.30, and 0.70 nm. HT-AIN buffer layer can have a significant impact on the surface morphology of Al0.3Ga0.7N/Al2O3-HEMT structures.

  2. New Al0.25Ga0.75N/GaN high electron mobility transistor with partial etched AlGaN layer

    Science.gov (United States)

    Yuan, Song; Duan, Baoxing; Yuan, Xiaoning; Cao, Zhen; Guo, Haijun; Yang, Yintang

    2016-05-01

    In this letter, a new Al0.25Ga0.75N/GaN high electron mobility transistor (HEMT) with the AlGaN layer is partial etched is reported for the first time. The two-dimensional electron gas (2DEG) density in the HEMTs is changed by partially etching the AlGaN layer. A new electric field peak is introduced along the interface between the AlGaN layer and the GaN buffer by the electric field modulation effect. The high electric field near the gate in the proposed Al0.25Ga0.75N/GaN HEMT is effectively decreased, which makes the surface electric field more uniform. Compared with the conventional structure, the breakdown voltage can be improved by 58% for the proposed Al0.25Ga0.75N/GaN HEMT and the current collapse can be reduced resulting from the more uniform surface electric field.

  3. Structure and energetics of high index Fe, Al, Cu and Ni surfaces using equivalent crystal theory

    Science.gov (United States)

    Rodriguez, Agustin M.; Bozzolo, Guillermo; Ferrante, John

    1993-01-01

    Equivalent crystal theory (ECT) is applied to the study of multilayer relaxations and surface energies of high-index faces of Fe, Al, Ni, and Cu. Changes in interplanar spacing as well as registry of planes close to the surface and the ensuing surface energies changes are discussed in reference to available experimental data and other theoretical calculations. Since ECT is a semiempirical method, the dependence of the results on the variation of the input used was investigated.

  4. GaAs/AlGaAs nanoheterostructures: simulation and application on high mobility transistors

    OpenAIRE

    Eduardo Martín Rodríguez; Estrella González R.

    2011-01-01

     This work analyses the features of GaAs/AlGaAs heterostructure, highlighting semiconductor junction properties. Charge confinement was produced when two materials having different band-gap were fixed; such high electron concentration is called two-dimensional electron gas (2DEG). Device simulation for smart integrated systems (DESSIS) is simulation software which uses physical models and robust numerical methods for simulating semiconductor devices and 3-5 element heterostructures. Results f...

  5. High-normal fasting glucose levels are associated with increased prevalence of impaired glucose tolerance in obese children.

    Science.gov (United States)

    Grandone, A; Amato, A; Luongo, C; Santoro, N; Perrone, L; del Giudice, E Miraglia

    2008-12-01

    The natural history of impaired glucose tolerance (IGT) and Type 2 diabetes among obese children is not clear. Although the cut-off for impaired fasting glucose (IFG) has recently been changed from 110 (6.1 mmol/l) to 100 mg/dl (5.6 mmol/l), it does not seem a reliable way to find all subjects with impaired glucose homeostasis. The aim of our study was to determine whether high-normal fasting glucose level could predict the occurrence of IGT and metabolic syndrome. Three hundred and twenty-three Italian obese children and adolescents were included in the study (176 females, mean age 11+/-2.9 yr; mean body mass index z-score: 3+/-0.6). Waist circumference, serum glucose, insulin, triglyceride, cholesterol HDL, blood pressure were evaluated and an oral glucose tolerance test (OGTT) was performed. The prevalence of IFG and IGT were respectively 1.5% (5 subjects) and 5% (18 patients); no diabetic patients were found. Metabolic syndrome was diagnosed in 20% of patients. Fasting glycemia values youths. Interestingly high-normal fasting plasma glucose levels constitute an independent risk factor for IGT among obese children and adolescents; therefore, this very easy-to-use parameter may help to identify obese patients at increased risk of diabetes or at least could suggest in which subjects to perform an OGTT.

  6. A high-resolution linkage map of the vicinity of the rice submergence tolerance locus Sub1.

    Science.gov (United States)

    Xu, K; Xu, X; Ronald, P C; Mackill, D J

    2000-05-01

    Resistance to submergence stress is an important breeding objective in areas where rice cultivars are subjected to complete inundation for a week or more. The present study was conducted to develop a high-resolution map of the region surrounding the submergence tolerance gene Sub1 in rice, which derives from the Indian cultivar FR13A. Submergence screening of 8-day-old plants of F3 families kept for 14 days submerged in 60 cm of water allowed an accurate classification of Sub1 phenotypes. Bulked segregant analysis was used to identify AFLP markers linked to Sub1. A population of 2950 F2 plants segregating for Sub1 was screened with two RFLP markers flanking the Sub1 locus, 2.4 and 4.9 cM away. Submergence tolerance was measured in the recombinant plants, and AFLP markers closely linked to Sub1 were mapped. Two AFLP markers cosegregated with Sub1 in this large population, and other markers were localized within 0.2 cM of Sub1. The high-resolution map should serve as the basis for map-based cloning of this important locus, as it will permit the identification of BAC clones spanning the region.

  7. A high-temperature tolerant species in clade 9 of the genus Phytophthora: P. hydrogena sp. nov.

    Science.gov (United States)

    Yang, Xiao; Gallegly, Mannon E; Hong, Chuanxue

    2014-01-01

    A previously unknown Phytophthora species was isolated from irrigation water in Virginia, USA. This novel species produces abundant noncaducous and nonpapillate sporangia in soil water extract solution. It sometimes produces chlamydospores and hyphal swellings in aged cultures and in Petri's solution. This species has optimum vegetative growth at 30 C and grows well at 35 C. The lowest and highest temperatures for growth are 5 and 40 C. All isolates examined in this study are compatibility type A1 and produce mostly plerotic oospores when paired with an A2 mating-type tester of P. cinnamomi. Sequence analyses of the rDNA internal transcribed spacer (ITS) regions and the mitochondrially encoded cytochrome c oxidase 1 (cox 1) gene placed this species in clade 9 of the genus Phytophthora. These characteristics support the description of this taxon as a new species for which we propose the name P. hydrogena sp. nov. Further phylogenetic and physiological investigations of clade 9 species revealed a high-temperature tolerant cluster including P. hydrogena, P. aquimorbida, P. hydropathica, P. irrigata, P. chrysanthemi, P. insolita, P. polonica and P. parsiana. These species all grow well at 35 C. The monophyly of the species in this heat-tolerant cluster except P. insolita and P. polonica is highly supported by the maximum-likelihood analyses of the ITS and cox 1 sequences.

  8. Lithium rich cathode/graphite anode combination for lithium ion cells with high tolerance to near zero volt storage

    Science.gov (United States)

    Crompton, K. R.; Staub, J. W.; Hladky, M. P.; Landi, B. J.

    2017-03-01

    Management of reversible lithium is an advantageous approach to design lithium ion cells that are tolerant to near zero volt (NZV) storage under fixed resistive load towards highly controllable, enhanced user-inactive safety. Presently, the first cycle loss from a high energy density Li-rich HE5050 cathode is used to provide excess reversible lithium when paired with an appropriately capacity matched mesocarbon microbead (MCMB) anode. Cells utilizing 1.2 M LiPF6 3:7 v/v ethylene carbonate:ethyl methyl carbonate electrolyte and a lithium reference were used for 3-electrode testing. After conditioning, a fixed resistive load was applied to 3-electrode cells for 72 or 168-h during which the anode potential and electrode asymptotic potential (EAP) remained less than the copper dissolution potential. After multiple storage cycles (room temperature or 40 °C), the NZV coulombic efficiency (cell reversibility) exceeded 97% and the discharge capacity retention was >98%. Conventional 2-electrode HE5050/MCMB pouch cells stored at NZV or open circuit for 3 days had nearly identical rate capability (up to 5C) and discharge performance stability (for 500 cycles under a 30% depth of discharge low-earth-orbit regime). Thus, lithium ion cells with appropriately capacity matched HE5050/MCMB electrodes have excellent tolerance to prolonged NZV storage, which can lead to enhanced user-inactive safety.

  9. Tolerance of Ricinus communis L. to Cd and screening of high Cd accumulation varieties for remediation of Cd contaminated soils.

    Science.gov (United States)

    Wu, Shanshan; Shen, Chuang; Yang, Zhongyi; Lin, Biyun; Yuan, Jiangang

    2016-11-01

    Response of castor (Ricinus communis L.) to cadmium (Cd) was assessed by a seed-suspending seedbed approach. Length of total radicle was the most sensitive indicator of Cd tolerance among the tested germination and growth characters. The ED50 value for Cd was 11.87 mg L(-1), indicating high Cd tolerance in castor. A pot experiment was conducted by growing 46 varieties of castor under CK (without Cd) and Cd1 (10 mg kg(-1) of Cd) and Cd2 (50 mg kg(-1) of Cd) treatments to investigate genotype variations in growth response and Cd accumulation of castor under different Cd exposures. Castor possessed high Cd accumulation ability; average shoot and root Cd concentrations of the 46 tested varieties were 21.83 and 185.43 mg kg(-1), and 174.99 and 1181.96 mg kg(-1) under Cd1 and Cd2, respectively. Great variation in Cd accumulation was observed among varieties, and Cd concentration of castor was genotype dependent. The correlation between biomass and Cd accumulation was significantly positive, while no significant correlation was observed between Cd concentration and Cd accumulation, which indicated that biomass performance is the dominant factor in determining Cd accumulation ability.

  10. Static synthesis of high-quality MCM-22 zeolite with high SiO2/Al2O3 ratio

    Institute of Scientific and Technical Information of China (English)

    LIU Zhicheng; SHEN Shaodian; TIAN Bozhi; SUN Jinyu; TU Bo; ZHAO Dongyuan

    2004-01-01

    We demonstrate a synthesis method to broaden the range of SiO2/Al2O3 ratio (30-100) of high-silica MCM-22 zeolites by prolonging the aging time of the gel before the crystallization. The synthesis conditions such as silica sources, chemical compositions of initial gel and aging time of gel were investigated in detail. High quality MCM-22products with various morphologies have been synthesized by optimize their synthesis conditions. Our results show that increasing of the aging time can make the gel be homogenization and promote their nucleus formation, which may avoid the formation of impurity phase and thus broaden the range of SiO2/Al2O3 ratio.

  11. Glucose tolerance and antioxidant activity of spent brewer's yeast hydrolysate with a high content of Cyclo-His-Pro (CHP).

    Science.gov (United States)

    Jung, Eun Young; Lee, Hyun-Sun; Choi, Jang Won; Ra, Kyung Soo; Kim, Mi-Ryung; Suh, Hyung Joo

    2011-03-01

    To elevate the Cyclo-His-Pro (CHP) content in yeast, the yeast hydrolysate that was obtained from enzymatic hydrolysis was subjected to various treatments. Flavourzyme-treated hydrolysate showed the highest CHP content (674.0 μg/g) among the various proteases treatments. Ultrafiltration was selected as the best method for concentrating CHP in yeast hydrolysate, based on the yields and CHP contents. In addition, we evaluated the radical scavenge and glucose tolerance of yeast hydrolysate with a high content of CHP. Yeast hydrolysate showed intense scavenging abilities of both 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. The IC(50) values of yeast hydrolysate on DPPH and ABTS radicals were 1.9 and 0.9 mg/mL, respectively. There were significant differences in glucose level between the diabetes-control and yeast hydrolysate group at 30, 60, 90, and 120 min after injection in a type 1 diabetes model (P CHP as an antioxidative and/or antidiabetic material for the preparation of functional foods. This study tried to develop a material containing a high content of CHP using yeast for possible applications of this cyclic dipeptide in the therapy of metabolic disorders. The yeast hydrolysate prepared with Flavourzyme showed a high level of CHP. The hydrolysate with a high content of CHP showed high levels of radical scavenging activities and oral glucose tolerance activity. Therefore, it is possible to use the yeast hydrolysate with high levels of CHP as an antioxidative and/or antidiabetic material for the preparation of functional foods.

  12. Insight into high-reflectivity AlN/GaN Bragg reflectors with spontaneously formed (Al,Ga)N transient layers at the interfaces

    Science.gov (United States)

    Gačević, Ž.; Eljarrat, A.; Peiró, F.; Calleja, E.

    2013-05-01

    This work gives a detailed insight into how the formation of (Al,Ga)N transient layers (TLs) at the interfaces of AlN/GaN Bragg reflectors modifies their structural and optical properties. While abrupt AlN/GaN interfaces are typically characterized with a network of microcracks, those with TLs are characterized with a network of nanocracks. Transmission electron microscopy reveals a strong correlation between strain and the TLs thickness, identifying thus the strain as the driving force for TLs formation. The AlN/GaN intermixing preserves the targeted stopband position (˜410 nm), whereas the peak reflectivity and the stopband width are both reduced, but still significantly high: >90% and >30 nm, respectively. To model their optical properties, a reduced refractive index contrast approximation is used, a novel method which yields an excellent agreement with the experiment.

  13. Step buffer layer of Al0.25Ga0.75N/Al0.08Ga0.92N on P-InAlN gate normally-off high electron mobility transistors

    Science.gov (United States)

    Shrestha, Niraj M.; Li, Yiming; Chang, E. Y.

    2016-07-01

    Normally-off AlGaN/GaN high electron mobility transistors (HEMTs) are indispensable devices for power electronics as they can greatly simplify circuit designs in a cost-effective way. In this work, the electrical characteristics of p-type InAlN gate normally-off AlGaN/GaN HEMTs with a step buffer layer of Al0.25Ga0.75N/Al0.1Ga0.9N is studied numerically. Our device simulation shows that a p-InAlN gate with a step buffer layer allows the transistor to possess normally-off behavior with high drain current and high breakdown voltage simultaneously. The gate modulation by the p-InAlN gate and the induced holes appearing beneath the gate at the GaN/Al0.25Ga0.75N interface is because a hole appearing in the p-InAlN layer can effectively vary the threshold voltage positively. The estimated threshold voltage of the normally-off HEMTs explored is 2.5 V at a drain bias of 25 V, which is 220% higher than the conventional p-AlGaN normally-off AlGaN/GaN gate injection transistor (GIT). Concurrently, the maximum current density of the explored HEMT at a drain bias of 10 V slightly decreases by about 7% (from 240 to 223 mA mm-1). At a drain bias of 15 V, the current density reached 263 mA mm-1. The explored structure is promising owing to tunable positive threshold voltage and the maintenance of similar current density; notably, its breakdown voltage significantly increases by 36% (from 800 V, GIT, to 1086 V). The engineering findings of this study indicate that novel p-InAlN for both the gate and the step buffer layer can feature a high threshold voltage, large current density and high operating voltage for advanced AlGaN/GaN HEMT devices.

  14. Neutron irradiation effects on AlGaN/GaN high electron mobility transistors

    Institute of Scientific and Technical Information of China (English)

    Lü Ling; Zhang Jin-Cheng; Xue Jun-Shuai; Ma Xiao-Hua; Zhang Wei; Bi Zhi-Wei; Zhang Yue; Hao Yue

    2012-01-01

    AlGaN/GaN high electron mobility transistors (HEMTs) were exposed to 1 MeV neutron irradiation at a neutron fluence of 1 × 1015 cm-2.The dc characteristics of the devices,such as the drain saturation current and the maximum transconductance,decreased after neutron irradiation. The gate leakage currents increased obviously after neutron irradiation.However,the rf characteristics,such as the cut-off frequency and the maximum frequency,were hardly affected by neutron irradiation.The AlGaN/GaN heterojunctions have been employed for the better understanding of the degradation mechanism.It is shown in the Hall measurements and capacitance-voltage tests that the mobility and concentration of two-dimensional electron gas (2DEG) decreased after neutron irradiation.There was no evidence of the full-width at half-maximum of X-ray diffraction (XRD) rocking curve changing after irradiation,so the dislocation was not influenced by neutron irradiation.It is concluded that the point defects induced in AlGaN and GaN by neutron irradiation are the dominant mechanisms responsible for performance degradations of AlGaN/GaN HEMT devices.

  15. Growth of oxide particles in FeCrAl- oxide dispersion strengthened steels at high temperature

    Science.gov (United States)

    Oono, N. H.; Ukai, S.; Hayashi, S.; Ohtsuka, S.; Kaito, T.; Kimura, A.; Torimaru, T.; Sakamoto, K.

    2017-09-01

    The growth of oxide particles in FeCrAl- oxide dispersion strengthened steel (ODSS) considering an accident condition of the light-water reactor at above 1500 K was studied by using a high-temperature annealing. Oxide particles grew from 9 nm to more than 50 nm as maximum at 1623 K for 27 h, with decreasing their number density in two orders of magnitude. Most of the oxide particles in 15Cr-7Al were identified as YAM or YAP, while the oxide particles in 15Cr-7Al-0.4Zr were identified trigonal Y4Zr3O12. Zr addition to 15Cr-7Al ODSS accelerated the growth of the oxide particles, which is quite contrary to the effect of Zr addition during sintering as suggested in the literature. The kinetics of coarsening was characterized by an equation of Ostwald ripening. The diffusion activation energies obtained in the present materials were quite larger than the conventional diffusion activation energy of Y in alpha-iron. Gibbs free energy of oxides should be considered to discuss the coarsening.

  16. Effect of layer thickness on the high temperature mechanical properties of Al/SiC nanolaminates

    Energy Technology Data Exchange (ETDEWEB)

    Lotfian, S. [IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Mayer, C.; Chawla, N. [Materials Science and Engineering, Arizona State University, Tempe, AZ 85287-6106 (United States); Llorca, J. [IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Department of Materials Science, Polytechnic University of Madrid, E.T.S. de Ingenieros de Caminos, 28040 Madrid (Spain); Misra, A.; Baldwin, J.K. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Molina-Aldareguía, J.M., E-mail: jon.molina@imdea.org [IMDEA Materials Institute, c/Eric Kandel 2, 28906 Getafe, Madrid (Spain)

    2014-11-28

    Composite laminates on the nanoscale have shown superior hardness and toughness, but little is known about their high temperature behavior. The mechanical properties (elastic modulus and hardness) were measured as a function of temperature by means of nanoindentation in Al/SiC nanolaminates, a model metal–ceramic nanolaminate fabricated by physical vapor deposition. The influence of the Al and SiC volume fraction and layer thicknesses was determined between room temperature and 150 °C and, the deformation modes were analyzed by transmission electron microscopy, using a focused ion beam to prepare cross-sections through selected indents. It was found that ambient temperature deformation was controlled by the plastic flow of the Al layers, constrained by the SiC, and the elastic bending of the SiC layers. The reduction in hardness with temperature showed evidence of the development of interface-mediated deformation mechanisms, which led to a clear influence of layer thickness on the hardness. - Highlights: • The mechanical behavior of Al/SiC nanolaminates was measured between 28 °C and 150 °C. • Room temperature hardness was controlled by the volume fraction of the constituents. • The hardness of all the nanolaminates decreased rapidly with temperature. • Reduction of hardness with temperature increased as the interface density increased.

  17. Synthesis and Characterization of Al-Cr-Pillared Montmorillonite with High Thermal Stability and Adsorption Capacity

    Institute of Scientific and Technical Information of China (English)

    CAO Ming-li; LIU Shi-zhen; YU Yong-fu

    2004-01-01

    Al-Cr-pillared montmorillonite was synthesized by using bentonite and Al-Cr pillaring solutionsas starting materials. The basal spacing and specific surface areas of the materials were significantly increased rela-tive to those of untreated clays. When the Al/Cr molar ratio ( R ) was 0.10, the d (001) value and specific surfacearea of pillared montmorillonite were 1.9194 nm and 165.7 m2 g- 1 , respectively. Thermal stability of the mate-rials was determined using calcined tests and X- ray diffraction (XRD) analysis. The materials formed at differentR(0.05;0.10;0.15;0.25) exhibit a high thermal stability at 300℃ , especially at initial R = 0.10, the basalinterlayer spacing of materials is stabilized at 1.7313 nm after calcined at 500℃ for 2 h. Adsorption behavior ofthe materials was studied by adsorption experiments. The results show that the Al- Cr-pillared montmorillonites ex-hibit much stronger adsorption capacity on Cr6+ in aqueous solution than untreated clays do.

  18. High temperature thermal analysis of Ni-Al alloys around the {gamma}{prime} composition

    Energy Technology Data Exchange (ETDEWEB)

    Battezzati, L.; Baricco, M.; Pascale, L. [Univ. di Torino (Italy)

    1998-06-05

    The region of the Ni-Al phase diagram close to the Ni{sub 3}Al ({gamma}{prime}) compound has been analyzed several times recognizing that {gamma}{prime} has an incongruent melting and its field of existence is narrow, bounded by the equilibria with the {gamma} terminal solid solution and the NiAl ({beta}) phase. With the availability of High Temperature Differential Scanning Calorimetry (HTDSC) as a sensitive technique for quantitative thermal analysis, it appeared useful to re-examine the portion of the phase diagram around {gamma}{prime}. In this paper the authors report data confirming Hilpert`s version of the phase diagram. In addition, the HTDSC analysis provides information on the enthalpy change during fusion not yet available in the literature, which also has implications in the analysis of the order-disorder transition in Ni{sub 3}Al. Furthermore, a detailed knowledge of the DSC behaviour of these alloys on melting and solidification is relevant as a reference basis to interpret data on analogous transformations in superalloys and intermetallics.

  19. The effect of the disulfideisomerase domain containing protein in the defense against polyhexamethylene biguanide of highly tolerant Acanthamoeba at the trophozoite stage

    Directory of Open Access Journals (Sweden)

    Fu-Chin Huang

    2016-12-01

    Full Text Available Acanthamoeba castellanii is a free-living protozoan pathogen capable of causing a blinding keratitis and fatal granulomatous encephalitis. Current treatment generally involves an hourly application of polyhexamethylene biguanide (PHMB over a period of several days but this is not entirely effective against all strains/isolates. The tolerance mechanisms of PHMB in Acanthamoeba cells remain unclear. In this study, we found that the mRNA expression level of disulfideisomerase domain containing protein (PDI increased rapidly in surviving cells of the highly PHMB-tolerant Acanthamoeba castellanii strain, NCKH_D, during PHMB treatment, but not in the ATCC standard strain. After PDI-specific silencing, NCKH_D was found to be more vulnerable to PHMB treatment. The results described above show that PDI is an important gene for PHMB tolerance ability in a highly PHMB-tolerant strain of Acanthamoeba and provide a new insight for more efficient medicine development for Acanthamoeba keratitis.

  20. Plant High-Affinity Potassium (HKT Transporters Involved in Salinity Tolerance: Structural Insights to Probe Differences in Ion Selectivity

    Directory of Open Access Journals (Sweden)

    Maria Hrmova

    2013-04-01

    Full Text Available High-affinity Potassium Transporters (HKTs belong to an important class of integral membrane proteins (IMPs that facilitate cation transport across the plasma membranes of plant cells. Some members of the HKT protein family have been shown to be critical for salinity tolerance in commercially important crop species, particularly in grains, through exclusion of Na+ ions from sensitive shoot tissues in plants. However, given the number of different HKT proteins expressed in plants, it is likely that different members of this protein family perform in a range of functions. Plant breeders and biotechnologists have attempted to manipulate HKT gene expression through genetic engineering and more conventional plant breeding methods to improve the salinity tolerance of commercially important crop plants. Successful manipulation of a biological trait is more likely to be effective after a thorough understanding of how the trait, genes and proteins are interconnected at the whole plant level. This article examines the current structural and functional knowledge relating to plant HKTs and how their structural features may explain their transport selectivity. We also highlight specific areas where new knowledge of plant HKT transporters is needed. Our goal is to present how knowledge of the structure of HKT proteins is helpful in understanding their function and how this understanding can be an invaluable experimental tool. As such, we assert that accurate structural information of plant IMPs will greatly inform functional studies and will lead to a deeper understanding of plant nutrition, signalling and stress tolerance, all of which represent factors that can be manipulated to improve agricultural productivity.

  1. Plant High-Affinity Potassium (HKT) Transporters involved in salinity tolerance: structural insights to probe differences in ion selectivity.

    Science.gov (United States)

    Waters, Shane; Gilliham, Matthew; Hrmova, Maria

    2013-04-09

    High-affinity Potassium Transporters (HKTs) belong to an important class of integral membrane proteins (IMPs) that facilitate cation transport across the plasma membranes of plant cells. Some members of the HKT protein family have been shown to be critical for salinity tolerance in commercially important crop species, particularly in grains, through exclusion of Na+ ions from sensitive shoot tissues in plants. However, given the number of different HKT proteins expressed in plants, it is likely that different members of this protein family perform in a range of functions. Plant breeders and biotechnologists have attempted to manipulate HKT gene expression through genetic engineering and more conventional plant breeding methods to improve the salinity tolerance of commercially important crop plants. Successful manipulation of a biological trait is more likely to be effective after a thorough understanding of how the trait, genes and proteins are interconnected at the whole plant level. This article examines the current structural and functional knowledge relating to plant HKTs and how their structural features may explain their transport selectivity. We also highlight specific areas where new knowledge of plant HKT transporters is needed. Our goal is to present how knowledge of the structure of HKT proteins is helpful in understanding their function and how this understanding can be an invaluable experimental tool. As such, we assert that accurate structural information of plant IMPs will greatly inform functional studies and will lead to a deeper understanding of plant nutrition, signalling and stress tolerance, all of which represent factors that can be manipulated to improve agricultural productivity.

  2. Microstructural stability of heat-resistant high-pressure die-cast Mg-4Al-4Ce alloy

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wei; Zhang, Jinghuai; Li, Guoqiang; Feng, Yan; Su, Minliang; Wu, Ruizhi; Zhang, Zhongwu [Harbin Engineering Univ. (China). Key Laboratory of Superlight Material and Surface Technology; Jiao, Yufeng [Jiamusi Univ. (China). College of Materials Science and Engineering

    2017-05-15

    The thermal stability of Al-RE (rare earth) intermetallic phases with individual RE for heat-resistant high-pressure die-casting Mg-Al-RE alloys is investigated. The results of this study show that the main strengthening phase of Mg-4Al-4Ce alloy is Al{sub 11}Ce{sub 3}, whose content is about 5 wt.% according to quantitative X-ray diffraction phase analysis. The Al{sub 11}Ce{sub 3} phase appears to have high thermal stability at 200 C and 300 C, while phase morphology change with no phase structure transition could occur for Al{sub 11}Ce{sub 3} when the temperature reaches 400 C. Furthermore, besides the kinds of rare earths and temperature, stress is also an influencing factor in the microstructural stability of Mg-4Al-4Ce alloy.

  3. High thermal tolerance of two Mediterranean cold-water coral species maintained in aquaria

    Science.gov (United States)

    Naumann, M. S.; Orejas, C.; Ferrier-Pagès, C.

    2013-09-01

    In the Mediterranean deep-sea, scleractinian cold-water corals (CWC) are observed to survive at the uppermost end of their presumed thermal distribution range (4-13 °C). Here, we show that 2 common CWC species (i.e. Dendrophyllia cornigera and Desmophyllum dianthus) maintained in aquaria can indeed tolerate considerably elevated seawater temperatures (17.5 ± 0.1 °C), while growing at similar ( D. dianthus) or significantly higher ( D. cornigera) rates than conspecifics cultured in parallel for 87 days at ambient Mediterranean deep-sea temperature (12.5 ± 0.1 °C). Neither differences in coral appearance nor mortality were evident for both species at either temperature. D. dianthus grew significantly faster (0.23 ± 0.08 % day-1) than D. cornigera (0.05 ± 0.01 % day-1) under ambient thermal conditions. Growth of D. cornigera increased significantly (0.14 ± 0.07 % day-1) at elevated temperature, while Desmophyllum dianthus growth showed no significant difference under both conditions. These findings suggest that D. dianthus and D. cornigera may be capable of surviving in warmer environments than previously reported, and thus challenge temperature as the paramount limiting environmental factor for the occurrence of some CWC species.

  4. Synthesis of High Crystalline Al-Doped ZnO Nanopowders from Al2O3 and ZnO by Radio-Frequency Thermal Plasma

    Directory of Open Access Journals (Sweden)

    Min-Kyeong Song

    2015-01-01

    Full Text Available High crystalline Al-doped ZnO (AZO nanopowders were prepared by in-flight treatment of ZnO and Al2O3 in Radio-Frequency (RF thermal plasma. Micron-sized (~1 μm ZnO and Al2O3 powders were mixed at Al/Zn ratios of 3.3 and 6.7 at.% and then injected into the RF thermal plasma torch along the centerline at a feeding rate of 6.6 g/min. The RF thermal plasma torch system was operated at the plate power level of ~140 kVA to evaporate the mixture oxides and the resultant vapor species were condensed into solid particles by the high flow rate of quenching gas (~7000 slpm. The FE-SEM images of the as-treated powders showed that the multipod shaped and the whisker type nanoparticles were mainly synthesized. In addition, these nanocrystalline structures were confirmed as the single phase AZO nanopowders with the hexagonal wurtzite ZnO structure by the XRD patterns and FE-TEM results with the SAED image. However, the composition changes of 0.3 and 1.0 at.% were checked for the as-synthesized AZO nanopowders at Al/Zn ratios of 3.3 and 6.7 at.%, respectively, by the XRF data, which can require the adjustment of Al/Zn in the mixture precursors for the applications of high Al doping concentrations.

  5. Explanation of threshold voltage scaling in enhancement-mode InAlN/AlN-GaN metal oxide semiconductor high electron mobility transistors on Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Alexewicz, A., E-mail: alexander.alexewicz@tuwien.ac.at [Vienna University of Technology, Floragasse 7, 1040 Vienna (Austria); Ostermaier, C.; Henkel, C.; Bethge, O. [Vienna University of Technology, Floragasse 7, 1040 Vienna (Austria); Carlin, J.-F.; Lugani, L.; Grandjean, N. [Ecole Polytechnique Federale de Lausanne, Station 3, 1015 Lausanne (Switzerland); Bertagnolli, E.; Pogany, D.; Strasser, G. [Vienna University of Technology, Floragasse 7, 1040 Vienna (Austria)

    2012-07-31

    We present enhancement-mode GaN high electron mobility transistors on Si substrates with ZrO{sub 2} gate dielectrics of thicknesses t{sub ox} between 10 and 24 nm. The oxide interlayers between the InAlN/AlN barrier and gate metal allow raising the device threshold voltage up to + 2.3 V and reduce gate leakage current to less than 100 nA/mm with a high drain current on/off ratio of 4 orders of magnitude. We use a model that explains the observed linear dependence of the threshold voltage on t{sub ox} and allows determining fixed charges at the oxide/barrier interface. - Highlights: Black-Right-Pointing-Pointer Enhancement-mode InAlN/AlN-GaN high electron mobility transistor (HEMT) Black-Right-Pointing-Pointer Metal oxide semiconductor HEMT with ZrO{sub 2} gate oxide Black-Right-Pointing-Pointer Linear decrease of threshold voltage with increasing gate oxide thickness Black-Right-Pointing-Pointer A model explaining that dependence is presented. Black-Right-Pointing-Pointer This model allows determining fixed charges at the InAlN/ZrO{sub 2} interface.

  6. Optimization of High Temperature Hoop Creep Response in ODS-Fe3Al Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kad, B.K.; Heatherington, J.H.; McKamey, C.; Wright, I.; Sikka, V.; Judkins, R.

    2003-04-22

    Oxide dispersion strengthened (ODS) Fe3Al alloys are currently being developed for heat-exchanger tubes for eventual use at operating temperatures of up to 1100 C in the power generation industry. The development challenges include (a) efforts to produce thin walled ODS-Fe3Al tubes, employing powder extrusion methodologies, with (b) adequate increased strength for service at operating temperatures to (c) mitigate creep failures by enhancing the as-processed grain size. A detailed and comprehensive research and development methodology is prescribed to produce ODS-Fe3Al thin walled tubes. Current single step extrusion consolidation methodologies typically yield 8ft. lengths of 1-3/8 inch diameter, 1/8 inch wall thickness ODS-Fe3Al tubes. The process parameters for such consolidation methodologies have been prescribed and evaluated as being routinely reproducible. Recrystallization treatments at 1200 C produce elongated grains (with their long axis parallel to the extrusion axis), typically 200-2000 {micro}m in diameter, and several millimeters long. The dispersion distribution is unaltered on a micro scale by recrystallization, but the high aspect ratio grain shape typically obtained limits grain spacing and consequently the hoop creep response. Improving hoop creep in ODS-alloys requires an understanding and manipulating the factors that control grain alignment and recrystallization behavior. Current efforts are focused on examining the processing dependent longitudinal vs. transverse creep anisotropy, and exploring post-extrusion methods to improve hoop creep response in ODS-Fe3Al alloy tubes. In this report we examine the mechanisms of hoop creep failure and describe our efforts to improve creep performance via variations in thermal-mechanical treatments.

  7. Oxide phase development upon high temperature oxidation of {gamma}-NiCrAl alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nijdam, T.J.; Pers, N.M. van der; Sloof, W.G. [Department of Materials Science and Engineering, Delft University of Technology, Rotterdamseweg 137, 2628 AL Delft (Netherlands)

    2006-03-15

    The amount of each oxide phase developed upon thermal oxidation of a {gamma}-Ni-27Cr-9Al (at.%) alloy at 1353 K and 1443 K and a partial oxygen pressure of 20 kPa is determined with in-situ high temperature X-ray Diffractometry (XRD). The XRD results are compared with microstructural observations from Scanning Electron Microscope (SEM) backscattered electron images, and model calculations using a coupled thermodynamic-kinetic oxidation model. It is shown that for short oxidation times, the oxide scale consists of an outer layer of NiO on top of an intermediate layer of Cr{sub 2}O{sub 3} and an inner zone of isolated {alpha}-Al{sub 2}O{sub 3} precipitates in the alloy. The amounts of Cr{sub 2}O{sub 3} and NiO in the oxide scale attain their maximum values when successively continuous Cr{sub 2}O{sub 3} and {alpha}-Al{sub 2}O{sub 3} layers are formed. Then a transition from very fast to slow parabolic growth kinetics occurs. During the slow parabolic growth, the total amount of non-protective oxide phases (i.e. all oxide phases excluding {alpha}-Al{sub 2}O{sub 3}) in the oxide scale maintain at an approximately constant value. The formation of NiCr{sub 2}O{sub 4} and subsequently NiAl{sub 2}O{sub 4} happens as a result of solid-state reactions between the oxide phases within the oxide scale. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  8. Phase composition and elemental partitioning in glass-ceramics containing high-Na/Al high level waste

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovsky, S.V., E-mail: profstef@mtu-net.ru [SIA Radon, 7th Rostovskii lane 2/14, Moscow 119121 (Russian Federation); Sorokaletova, A.N. [SIA Radon, 7th Rostovskii lane 2/14, Moscow 119121 (Russian Federation); Nikonov, B.S. [Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry RAS, Staromonetniy lane 35, Moscow 109017 (Russian Federation)

    2012-05-15

    Mixtures of surrogates of high level waste with high sodium and aluminum contents and sodium-lithium borosilicate frit were melted in alumina crucibles in a resistive furnace followed by quenching of one portion of the melt and annealing of the residual material in a turned-off furnace. The annealed materials with waste loading of up to 45 wt.% contained minor spinel type phase and trace of nepheline (Na,K)AlSiO{sub 4}. In the annealed materials contained waste oxides in amount of 50 wt.% and more nepheline and spinel were found to be major and minor phases, respectively. At high waste loadings two extra phases: Cs-aluminosilicate (CsAlSiO{sub 4}) and mixed Na/Cs-aluminosilicate were found in amount of 3-5 vol.% each. The latter phase contains of up to {approx}5.7 wt.% SO{sub 3} or 0.13 formula units S (Na{sub 0.75}K{sub 0.05}Cs{sub 0.29}Ca{sub 0.02}Sr{sub 0.02}Al{sub 0.99}Fe{sub 0.03}Si{sub 0.76}S{sub 0.13}O{sub 4}). Sulfur incorporation as S{sup 6+} or SO{sub 4}{sup 2-} ions into crystal lattice may be facilitated in the presence of large-size Cs{sup +} cations. Simplified suggested formula of this phase may be represented as Na{sub 0.8}Cs{sub 0.3}AlSi{sub 0.8}S{sub 0.1}O{sub 3.95}. It was also synthesized by sintering of mixture of chemicals at 1300 Degree-Sign C and found to be instable at temperatures higher than 1300 Degree-Sign C.

  9. Development of high plasticity Al-Si alloy and its casting process

    Institute of Scientific and Technical Information of China (English)

    郭国文; 李元元; 陈维平; 张大童; 龙雁

    2002-01-01

    Aiming to meet the challenge of the shape complexity and high plasticity demanded for the upper connective plate(UCP) in motorcycle, a high plasticity Al-Si alloy named HGZL-02 was developed by optimizing the chemical composition and casting process. Premium UCP castings were obtained by using optimized casting process. Results show that fine and dense microstructure are obtained in the UCP castings. An average of 224MPa in ultimate tensile strength, 149MPa in yield strength and 13.2% in elongation are achieved for T6 heat-treated UPS castings.

  10. Microstructural Evolution of Ti-6Al-4V during High Strain Rate Conditions of Metal Cutting

    Science.gov (United States)

    Dong, Lei; Schneider, Judy

    2009-01-01

    The microstructural evolution following metal cutting was investigated within the metal chips of Ti-6Al-4V. Metal cutting was used to impose a high strain rate on the order of approx.10(exp 5)/s within the primary shear zone as the metal was removed from the workpiece. The initial microstructure of the parent material (PM) was composed of a bi-modal microstructure with coarse prior grains and equiaxed primary located at the boundaries. After metal cutting, the microstructure of the metal chips showed coarsening of the equiaxed primary grains and lamellar. These metallographic findings suggest that the metal chips experienced high temperatures which remained below the transus temperature.

  11. High-power AlGaAs channeled substrate planar diode lasers for spaceborne communications

    Science.gov (United States)

    Connolly, J. C.; Goldstein, B.; Pultz, G. N.; Slavin, S. E.; Carlin, D. B.; Ettenberg, M.

    1988-01-01

    A high power channeled substrate planar AlGaAs diode laser with an emission wavelength of 8600 to 8800 A was developed. The optoelectronic behavior (power current, single spatial and spectral behavior, far field characteristics, modulation, and astigmatism properties) and results of computer modeling studies on the performance of the laser are discussed. Lifetest data on these devices at high output power levels is also included. In addition, a new type of channeled substrate planar laser utilizing a Bragg grating to stabilize the longitudinal mode was demonstrated. The fabrication procedures and optoelectronic properties of this new diode laser are described.

  12. Fabrication and mechanical properties of AlCoNiCrFe high-entropy alloy particle reinforced Cu matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jian, E-mail: chenjian@xatu.edu.cn [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Niu, Pengyun; Wei, Ting [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Hao, Liang [College of Architecture and Civil Engineering, Xi' an University of Science and Technology, Xi' an 710054 (China); Liu, Yunzi [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China); Wang, Xianhui, E-mail: xhwang693@xaut.edu.cn [School of Materials Science and Engineering, Xi' an University of Technology, Xi' an, Shaanxi 710048 (China); Peng, Yuli [School of Materials Science and Chemical Engineering, Xi' an Technological University, Xi' an, Shaanxi 710021 (China)

    2015-11-15

    The AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying and the AlCoNiCrFe high-entropy alloy reinforced Cu matrix composites were subsequently fabricated by powder metallurgy. The phase constituents and morphology of the alloying powders were characterized by X-ray diffractometer and scanning electron microscope, the microstructures of the Cu base composites were characterized by scanning electron microscope and transmission electron microscope, and the compression tests were made as well. The results show that the AlCoNiCrFe high-entropy alloy can form after milling for 24 h. During sintering process, no grain growth occurs and no intermetallic phases present in the AlCoNiCrFe high-entropy alloy in the Cu base composite. Compression tests show that the AlCoNiCrFe high-entropy alloy has a better strengthening effect than metallic glasses and the yield strength of the Cu matrix composite reinforced with the AlCoNiCrFe high-entropy alloy is close to the value predicted by the Voigt model based on the equal strain assumption. - Graphical abstract: AlCoNiCrFe HEA has a better strengthening effect than metallic glasses for particulate reinforced metal matrix composites. The yield strength of the Cu base composite reinforced with the AlCoNiCrFe HEA is close to the upper bound calculated by Voigt model. - Highlights: • AlCoNiCrFe high-entropy alloy was prepared by mechanical alloying. • A novel Cu base composite reinforced with AlCoNiCrFe was fabricated. • No grain growth and no intermetallic phase present in AlCoNiCrFe during sintering. • AlCoNiCrFe has a better strengthening effect than metallic glassy in composites.

  13. Microstructure and texture development during high-strain torsion of NiAl

    Energy Technology Data Exchange (ETDEWEB)

    Kloeden, B.

    2006-07-01

    In this study polycrystalline NiAl has been subjected to torsion deformation. The deformation, microstructure and texture development subject to the shear strain are studied by different techniques (Electron Back-Scatter and High Energy Synchrotron Radiation). Beside the development of microstructure and texture with shear strain, the effect of an initial texture as well as the deformation temperature on the development of texture and microstructure constitute an important part of this study. Therefore, samples with three different initial textures were deformed in the temperature range T=700 K-1300 K. The shear stress-shear strain curves are characterized by a peak at low strains, which is followed by softening and a steady state at high strains. Grain refinement takes place for all samples and the average grain size decreases with temperature. For temperatures T>1000 K, discontinuous dynamic recrystallization occurs, by which new grains form by nucleation and subsequent growth. The texture is characterized by two components, {l_brace}100{r_brace}<100> (cube,C) and {l_brace}110{r_brace}<100> (Goss,G). Torsional creep of NiAl is characterized by a stress exponent, which depends on temperature and an activation energy, which is stress dependent. The Swift effect, due to which samples change their axial dimension during torsion without applied axial stress, is observed for NiAl. (orig.)

  14. High strain rate tensile behavior of Al-4.8Cu-1.2Mg alloy

    Energy Technology Data Exchange (ETDEWEB)

    Bobbili, Ravindranadh, E-mail: ravindranadh@dmrl.drdo.in; Paman, Ashish; Madhu, V.

    2016-01-10

    The purpose of the current study is to perform quasi static and high strain rate tensile tests on Al-4.8Cu-1.2Mg alloy under different strain rates ranging from 0.01–3500/s and also at temperatures of 25,100, 200 and 300 °C. The combined effect of strain rate, temperature and stress triaxiality on the material behavior is studied by testing both smooth and notched specimens. Johnson–Cook (J–C) constitutive and fracture models are established based on high strain rate tensile data obtained from Split hopkinson tension bar (SHTB) and quasi-static tests. By modifying the strain hardening and strain rate hardening terms in the Johnson–Cook (J–C) constitutive model, a new J–C constitutive model of Al-4.8Cu-1.2Mg alloy was obtained. The improved Johnson–Cook constitutive model matched the experiment results very well. With the Johnson–Cook constitutive and fracture models, numerical simulations of tensile tests at different conditions for Al-4.8Cu-1.2Mg alloy were conducted. Numerical simulations are performed using a non-linear explicit finite element code autodyn. Good agreement is obtained between the numerical simulation results and the experiment results. The fracture surfaces of specimens tested under various strain rates and temperatures were studied under scanning electron microscopy (SEM).

  15. Screening for High-Temperature Tolerant Cotton Cultivars by Testing In Vitro Pollen Germination, Pollen Tube Growth and Boll Retention

    Institute of Scientific and Technical Information of China (English)

    Zhi Liu; You-Lu Yuan; Shao-Qing Liu; Xiao-Nan Yu; Li-Qun Rao

    2006-01-01

    With radical global climate change and global warming, high temperature stress has become one of major factors exerting a major influence on crop production. In the cotton (Gossypium hirsutum L.)-growing areas of China, especially in the Yangtze River valley, unexpected periodic episodes of extreme heat stress usually occur in July and August, the peak time of cotton flowering and boll loading, resulting in lower boll set and lint yield. Breeding programs for screening high temperature-tolerant cotton germplasm and cultivars are urgent in order to stabilize yield in the current and future warmer weather conditions. In the present study, 14 cotton cultivars were quantified for in vitro pollen germination and pollen tube growth in response to temperatures ranging from 10 to 50 ℃ at 5 ℃ intervals. Different cotton genotypes varied in their in vitro pollen germination and pollen tube length responses to the different temperatures. Maximum pollen germination and pollen tube length ranged from 25.2% to 56.2% and from 414 to 682 μm, respectively.The average cardinal temperatures (Tmin, Topt, and Tmax) also varied among the 14 cultivars and were 11.8,27.3, and 42.7 ℃ for pollen germination and 11.8, 27.8, and 44.1 ℃ for maximum pollen tube length. Variations in boll retention and boll numbers per plant in field experiments were found for the 14 cotton cultivars and the boll retention and boll retained per plant on 20 August varied considerably in different years according to weather conditions. Boll retention on 20 August was highly correlated with maximum pollen germination (R2=0.84) and pollen tube length (R2=0.64). A screening method based on principle component analysis of the combination of pollen characteristics in an in vitro experiment and boll retention testing in the field environment was used in the present study and, as a result, the 14 cotton cultivars could be classified as tolerant, moderately tolerant, moderately susceptible and susceptible to high

  16. Occurrence of the putatively heat-tolerant Symbiodinium phylotype D in high-latitudinal outlying coral communities

    Science.gov (United States)

    Lien, Yi-T.; Nakano, Y.; Plathong, S.; Fukami, H.; Wang, Jih-T.; Chen, C. A.

    2007-03-01

    Biogeographic investigations have suggested that coral-symbiont associations can adapt to higher temperatures by hosting a heat-tolerant Symbiodinium, phylotype D. It is hypothesized that phylotype D is absent in high latitudes due to its heat-tolerant characteristics. In this study, this hypothesis was tested by examining the symbiont diversity in a scleractinian coral, Oulastrea crispata, throughout its entire latitudinal distribution range in the West Pacific. Molecular phylotyping of the 5'-end of the nuclear large subunit of ribosomal DNA (lsu rDNA) indicated that phylotype D was the dominant Symbiodinium in O. crispata from the tropical reefs to the marginal non-reefal coral communities. Several colonies of tropical populations were associated with phylotype C, either alone or simultaneously with phylotype D. Analysis of the polymerase chain reaction products using single-strand conformation polymorphism (SSCP) detected relatively low densities of phylotype C in most of the O. crispata colonies surveyed. These results provide evidence for the occurrence of phylotype D in cold-water outlying coral communities. The dominant occurrence of phylotype C in some O. crispata colonies on tropical reefs and the relatively low densities of phylotype C identified by SSCP in subtropical and temperate populations show that the dominant symbiont type can vary in this coral species and that multiple symbionts can co-occur in the same host.

  17. Tolerability of piperacillin/tazobactam in children and adolescents after high dose radio-/chemotherapy and autologous stem cell transplantation.

    Science.gov (United States)

    Nürnberger, W; Bönig, H; Burdach, S; Göbel, U

    1998-01-01

    The combination of piperacillin with tazobactam (PIP/TAZ) extends the activity of piperacillin against gram-positive, gram-negative, and anaerobic bacteria. The broad-spectrum of this formulation, together with its low degree of organ toxicity observed in adults, makes PIP/TAZ a tempting choice for children with radio-/chemotherapy-induced neutropenia. However, the use of PIP/TAZ is not yet approved for children under 12 years of age. The tolerability of PIP/TAZ was assessed in 19 children and adolescents between 2 and 18 years of age who developed a fever during aplasia after high dose radio-/chemotherapy and autologous stem cell transplantation (HD-SCT) for primary multifocal or relapsed solid tumours. Treatment with PIP/TAZ was initiated on average 3 days after HD-SCT, and the treatment was continued for approximately 10 days. Both clinical observation and laboratory studies showed no relevant alterations that would have been attributable to PIP/TAZ treatment. These results indicate that PIP/TAZ appears to be well tolerated in children during the acute phase of HD-SCT.

  18. Using ammonium-tolerant yeast isolates: Candida halophila and Rhodotorula glutinis to treat high strength fermentative wastewater.

    Science.gov (United States)

    Yang, Q; Yang, M; Hei, L; Zheng, S

    2003-03-01

    Two ammonium-tolerant yeast strains were isolated from sludge samples contaminated with monosodium glutamate manufacturing wastewater and were identified as Candida haplophila and Rhodotorula glutinis. The tolerance of the two yeast isolates to ammonia and their chemical oxygen demand (COD) removal perfomances were evaluated under batch and bench-scale conditions. The mixture of the two isolates was found to grow well in an artificial medium containing 25% (NH4)2SO4 and could effectively remove COD from monosodium glutamate wastewater even when the concentrations of NH4+-N and free NH3-N reached as high as 18,977 and 879 mg l(-1) respectively. A fixed-bed yeast reactor, which was initially inoculated with the yeast mixture, permitted a constant COD removal rate of over 80% during a period of near 2-month continuous running even when the influent COD was increased from 8,000 to 25,000 mg l(-1). The effluent was accompanied with suspended solids (SS) of over 4,500 mg l(-1), which was mainly composed of yeast cells and could be considered as a source of animal forage additive. The residual COD of effluents from the yeast reactor could be further reduced to under 500 mg l(-1) by a combination process of activated sludge treatment and coagulation technologies.

  19. High prevalence of multidrug-tolerant bacteria and associated antimicrobial resistance genes isolated from ornamental fish and their carriage water.

    Directory of Open Access Journals (Sweden)

    David W Verner-Jeffreys

    Full Text Available BACKGROUND: Antimicrobials are used to directly control bacterial infections in pet (ornamental fish and are routinely added to the water these fish are shipped in to suppress the growth of potential pathogens during transport. METHODOLOGY/PRINCIPAL FINDINGS: To assess the potential effects of this sustained selection pressure, 127 Aeromonas spp. isolated from warm and cold water ornamental fish species were screened for tolerance to 34 antimicrobials. Representative isolates were also examined for the presence of 54 resistance genes by a combination of miniaturized microarray and conventional PCR. Forty-seven of 94 Aeromonas spp. isolates recovered from tropical ornamental fish and their carriage water were tolerant to > or =15 antibiotics, representing seven or more different classes of antimicrobial. The quinolone and fluoroquinolone resistance gene, qnrS2, was detected at high frequency (37% tested recent isolates were positive by PCR. Class 1 integrons, IncA/C broad host range plasmids and a range of other antibiotic resistance genes, inc