Science.gov

Sample records for support studies expansion

  1. Stakeholder Support for School Food Policy Expansions

    ERIC Educational Resources Information Center

    Pettigrew, Simone; Pescud, Melanie; Donovan, Robert J.

    2012-01-01

    The aim of this study was to assess the extent to which parents and school-based stakeholders (principals, teachers, canteen managers and Parents & Citizen Committee presidents) are supportive of potential expansions to a new school food policy. Eight additional policy components elicited in preliminary focus groups with parents and 19 additional…

  2. Welwistatin Support Studies: Expansion and Limitation of Aryllead(IV) Coupling Reactions

    PubMed Central

    Xia, Jibo; Brown, Lauren E.

    2008-01-01

    Recent support studies on the total synthesis of the welwitstatin system are described. The target step involves lead-mediated arylation of sterically demanding aryl groups and carbon acid coupling partners in order to establish the highly congested tetracyclic core structure. Type 7 β-ketoesters and β-ketonitriles were successfully arylated with a variety of ortho- and meta-subsituted aryllead compounds generated by a halogen-boron-lead exchange sequence. The enolates of compounds 15, 19 and 25, each bearing all-carbon quaternary centers adjacent to the arylation site, failed to couple. PMID:17685656

  3. Urban Expansion Study

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Under an Egyptian government contract, PADCO studies urban growth in the Nile Area. They were assisted by LANDSAT survey maps and measurements provided by TAC. TAC had classified the raw LANDSAT data and processed it into various categories to detail urban expansion. PADCO crews spot checked the results, and correlations were established.

  4. Low thermal expansion seal ring support

    DOEpatents

    Dewis, David W.; Glezer, Boris

    2000-01-01

    Today, the trend is to increase the temperature of operation of gas turbine engines. To cool the components with compressor discharge air, robs air which could otherwise be used for combustion and creates a less efficient gas turbine engine. The present low thermal expansion sealing ring support system reduces the quantity of cooling air required while maintaining life and longevity of the components. Additionally, the low thermal expansion sealing ring reduces the clearance "C","C'" demanded between the interface between the sealing surface and the tip of the plurality of turbine blades. The sealing ring is supported by a plurality of support members in a manner in which the sealing ring and the plurality of support members independently expand and contract relative to each other and to other gas turbine engine components.

  5. Studies on counterstreaming plasma expansion

    NASA Technical Reports Server (NTRS)

    Singh, N.; Thiemann, H.; Schunk, R. W.

    1986-01-01

    Recent studies on counterstreaming plasma expansions are summarized. The basic phenomenon of plasma expansion is reviewed, and results from one-dimensional simulations of counterstreaming plasma expansion are discussed. Results from simulations based on an electrostatic particle-in-cell code, in which the dynamics of both the electrons and ions are exactly followed, are discussed. The formation of electrostatic shocks is addressed. Finally, results are presented on the ionospheric plasma expansion along the geomagnetic flux tubes by solving the hydrodynamic equations.

  6. Analysis of the outcome in patients with cervical spondylotic myelopathy, undergone canal expansive laminoplasty supported with instrumentation in a group of Indian population – a prospective study

    PubMed Central

    Mandal, Subhadip; Banerjee, U.; Mukherjee, A.S.; Kundu, Srikanta

    2016-01-01

    Background Chronic compression of the cervical spinal cord leads to a clinical syndrome of cervical spondylotic myelopathy (CSM). Clinical symptoms of cervical spondylotic myelopathy (CSM) or cervical myeloradiculopathies result in spinal cord and root dysfunction. The primary aims of surgical intervention for multilevel myelopathy are to decompress the spinal cord and maintain stability of the cervical spine. Secondary aims are to minimize complications which include long-term pain and motion loss. Laminoplasty as either single-door or double-door technique and with/without instrumentation is an established mode of surgical treatment. The purpose of our study was to evaluate the result of single-door laminoplasty technique, supported with instrumented fixation in patients with multilevel degenerative cervical spondylotic myeloradiculopathy. Methods A prospective and without control study has been conducted in the institution in 17 patients with CSM, operated by canal expansive single-door laminoplasty (Hirabayashi technique) between April 2010 to April 2015. These patients were followed up for at least 3 years with both clinical and radiographic evaluations. Results On clinical evaluation, 15 of the 17 patients (87%) experienced relief of their symptoms. According to the Nurick classification, 11 patients’ demonstrated improvement by one grade, two patients improved by two grades, two patients were unchanged and two had worsening of the Nurick grade. Conclusions The results of this study regarding the use of open-door laminoplasty with instrumented fixation suggest that this technique is a satisfactory alternative for cases of multilevel cervical spondylotic myelopathy without deformation. Level of Evidence Level III therapeutic study. PMID:27441175

  7. Analysis of de novo HOXA13 polyalanine expansions supports replication slippage without repair in their generation.

    PubMed

    Owens, Kailey M; Quinonez, Shane C; Thomas, Peedikayil E; Keegan, Catherine E; Lefebvre, Nanci; Roulston, Diane; Larsen, Christine A; Stadler, H Scott; Innis, Jeffrey W

    2013-05-01

    Polyalanine repeat expansion diseases are hypothesized to result from unequal chromosomal recombination, yet mechanistic studies are lacking. We identified two de novo cases of hand-foot-genital syndrome (HFGS) associated with polyalanine expansions in HOXA13 that afforded rare opportunities to investigate the mechanism. The first patient with HFGS was heterozygous for a de novo nine codon polyalanine expansion. Haplotype investigation showed that the expansion arose on the maternally inherited chromosome but not through unequal crossing over between homologs, leaving unequal sister chromatid exchange during mitosis or meiosis or slipped mispairing as possible explanations. The asymptomatic father of the second patient with HFGS was mosaic for a six codon polyalanine expansion. Multiple tissue PCR and clonal analysis of paternal fibroblasts showed only expansion/WT and WT/WT clones, and haplotype data showed that two unaffected offspring inherited the same paternal allele without the expansion, supporting a postzygotic origin. Absence of the contracted allele in the mosaic father does not support sister chromatid exchange in the origin of the expansion. Mosaicism for HOXA13 polyalanine expansions may be associated with a normal phenotype, making examination of parental DNA essential in apparently de novo HFGS cases to predict accurate recurrence risks. We could not find an example in the literature where unequal sister chromatid exchange has been proven for any polyalanine expansion, suggesting that the principal mechanism for polyalanine expansions (and contractions) is slipped mispairing without repair or that the true frequency of unequal sister chromatid exchange involving these repeats is low. PMID:23532960

  8. Mechanistic study on lung cancer mortality after radon exposure in the Wismut cohort supports important role of clonal expansion in lung carcinogenesis.

    PubMed

    Zaballa, I; Eidemüller, M

    2016-08-01

    Lung cancer mortality after radon exposure in the Wismut cohort was analyzed using the two-stage clonal expansion (TSCE) model. A total of 2996 lung cancer deaths among the 58,695 male workers were observed during the follow-up period between 1946 and 2003. Adjustment to silica exposure was performed to find a more accurate estimation of the risk of radon exposure. An additional analysis with the descriptive excess relative risk (ERR) model was carried out for comparison. The TSCE model that best describes the data is nonlinear in the clonal expansion with radon exposure and has a saturation level at an exposure rate of [Formula: see text]. The excess relative risk decreases with age and shows an inverse exposure rate effect. In comparison with the ERR model, the TSCE model predicts a considerably larger risk for low exposures rates below [Formula: see text]. Comparison to other mechanistic studies of lung cancer after exposure to alpha particles using the TSCE model reveals an extraordinary consistency in the main features of the exposure response, given the diversity in the characteristics of the cohorts and the exposure across different studies. This suggests that a nonlinear response mechanism in the clonal expansion, with some level of saturation at large exposure rates, may be playing a crucial role in the development of lung cancer after alpha particle irradiation. PMID:27334643

  9. High flux expansion divertor studies in NSTX

    SciTech Connect

    Soukhanovskii, V A; Maingi, R; Bell, R E; Gates, D A; Kaita, R; Kugel, H W; LeBlanc, B P; Maqueda, R; Menard, J E; Mueller, D; Paul, S F; Raman, R; Roquemore, A L

    2009-06-29

    Projections for high-performance H-mode scenarios in spherical torus (ST)-based devices assume low electron collisionality for increased efficiency of the neutral beam current drive. At lower collisionality (lower density), the mitigation techniques based on induced divertor volumetric power and momentum losses may not be capable of reducing heat and material erosion to acceptable levels in a compact ST divertor. Divertor geometry can also be used to reduce high peak heat and particle fluxes by flaring a scrape-off layer (SOL) flux tube at the divertor plate, and by optimizing the angle at which the flux tube intersects the divertor plate, or reduce heat flow to the divertor by increasing the length of the flux tube. The recently proposed advanced divertor concepts [1, 2] take advantage of these geometry effects. In a high triangularity ST plasma configuration, the magnetic flux expansion at the divertor strike point (SP) is inherently high, leading to a reduction of heat and particle fluxes and a facilitated access to the outer SP detachment, as has been demonstrated recently in NSTX [3]. The natural synergy of the highly-shaped high-performance ST plasmas with beneficial divertor properties motivated a further systematic study of the high flux expansion divertor. The National Spherical Torus Experiment (NSTX) is a mid-sized device with the aspect ratio A = 1.3-1.5 [4]. In NSTX, the graphite tile divertor has an open horizontal plate geometry. The divertor magnetic configuration geometry was systematically changed in an experiment by either (1) changing the distance between the lower divertor X-point and the divertor plate (X-point height h{sub X}), or by (2) keeping the X-point height constant and increasing the outer SP radius. An initial analysis of the former experiment is presented below. Since in the divertor the poloidal field B{sub {theta}} strength is proportional to h{sub X}, the X-point height variation changed the divertor plasma wetted area due to

  10. EXAFS studies of local thermal expansion

    SciTech Connect

    Beccara, S.; Dalba, G.; Fornasini, P.; Grisenti, R.; Sanson, A.; Rocca, F.; Purans, J.; Diop, D.

    2003-01-24

    Original information on local thermal expansion can be obtained through a cumulant analysis of EXAFS. The difference between first and third EXAFS cumulants, and the comparison with Bragg diffraction results, can help in disentangling the contributions to thermal expansion of potential anharmonicity and geometrical effects. In germanium, the perpendicular Mean Square Relative Displacement has been obtained from EXAFS. In Ag2O, whose framework structure exhibits negative thermal expansion, a positive expansion of the Ag-O bond has been measured and the deformation of the Ag4O structural units monitored.

  11. OMV studies ethylene expansion in Germany

    SciTech Connect

    1996-10-23

    OMV(Vienna) is evaluating plans to debottleneck its ethylene plant at Burghausen from 310,000 m.t./year to at least 400,000 m.t./year. Senior v.p. Jochen Berger says OMV is studying the limits to which the cracker can be expanded. {open_quotes}We`re pretty sure we can go to 400,000 m.t./year, but in two months we`ll have a better idea,{close_quotes} says Berger. The expansion will also depend on the future requirements of downstream operations at the Burghausen site, which include OMV plastics subsidiary PCD`s high-density polyethylene and polypropylene units and the vinyl chloride monomer and polyvinyl chloride units operated by Hoechst-Wacker joint venture Vinnolit.

  12. Elastic hydrogel substrate supports robust expansion of murine myoblasts and enhances their engraftment

    SciTech Connect

    Ding, Ke; Yang, Zhong; Xu, Jian-zhong; Liu, Wen-ying; Zeng, Qiang; Hou, Fang; Lin, Sen

    2015-09-10

    The application of satellite cell-derived myoblasts in regenerative medicine has been restricted by the rapid loss of stemness during in vitro cell expansion using traditional culture systems. However, studies published in the past decade have highlighted the influence of substrate elasticity on stem cell fate and revealed that culture on a soft hydrogel substrate can promote self-renewal and prolong the regenerative potential of muscle stem cells. Whether hydrogel substrates have similar effects after long-term robust expansion remains to be determined. Herein we prepared an elastic chitosan/beta-glycerophosphate/collagen hydrogel mimicking the soft microenvironment of muscle tissues for use as the substrate for satellite cell culture and investigated its influence on long-term cell expansion. After 20 passages in culture, satellite cell-derived myoblasts cultured on our hydrogel substrate exhibited significant improvements in proliferation capability, cell viability, colony forming frequency, and potential for myogenic differentiation compared to those cultured on a routine rigid culture surface. Immunochemical staining and western blot analysis both confirmed that myoblasts cultured on the hydrogel substrate expressed higher levels of several differentiation-related markers, including Pax7, Pax3, and SSEA-1, and a lower level of MyoD compared to myoblasts cultured on rigid culture plates (all p<0.05). After transplantation into the tibialis anterior of nude mice, myoblasts that had been cultured on the hydrogel substrate demonstrated a significantly greater engraftment efficacy than those cultured on the traditional surface. Collectively, these results indicate that the elastic hydrogel substrate supported robust expansion of murine myoblasts and enhanced their engraftment in vivo. - Highlights: • An elastic hydrogel was designed to mimic the pliable muscle tissue microenvironment. • Myoblasts retained their stemness in long-term culture on the elastic

  13. MtDNA analysis of global populations support that major population expansions began before Neolithic Time

    NASA Astrophysics Data System (ADS)

    Zheng, Hong-Xiang; Yan, Shi; Qin, Zhen-Dong; Jin, Li

    2012-10-01

    Agriculture resulted in extensive population growths and human activities. However, whether major human expansions started after Neolithic Time still remained controversial. With the benefit of 1000 Genome Project, we were able to analyze a total of 910 samples from 11 populations in Africa, Europe and Americas. From these random samples, we identified the expansion lineages and reconstructed the historical demographic variations. In all the three continents, we found that most major lineage expansions (11 out of 15 star lineages in Africa, all autochthonous lineages in Europe and America) coalesced before the first appearance of agriculture. Furthermore, major population expansions were estimated after Last Glacial Maximum but before Neolithic Time, also corresponding to the result of major lineage expansions. Considering results in current and previous study, global mtDNA evidence showed that rising temperature after Last Glacial Maximum offered amiable environments and might be the most important factor for prehistorical human expansions.

  14. Advanced life support study

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Summary reports on each of the eight tasks undertaken by this contract are given. Discussed here is an evaluation of a Closed Ecological Life Support System (CELSS), including modeling and analysis of Physical/Chemical Closed Loop Life Support (P/C CLLS); the Environmental Control and Life Support Systems (ECLSS) evolution - Intermodule Ventilation study; advanced technologies interface requirements relative to ECLSS; an ECLSS resupply analysis; the ECLSS module addition relocation systems engineering analysis; an ECLSS cost/benefit analysis to identify rack-level interface requirements of the alternate technologies evaluated in the ventilation study, with a comparison of these with the rack level interface requirements for the baseline technologies; advanced instrumentation - technology database enhancement; and a clean room survey and assessment of various ECLSS evaluation options for different growth scenarios.

  15. Mesenchymal Stem Cell-Derived Microvesicles Support Ex Vivo Expansion of Cord Blood-Derived CD34+ Cells

    PubMed Central

    Xie, Hui; Sun, Li; Zhang, Liming; Liu, Teng; Chen, Li; Zhao, Aiqi; Lei, Qian; Gao, Fei; Zou, Ping; Li, Qiubai; Guo, An-yuan; Chen, Zhichao; Wang, Hongxiang

    2016-01-01

    Mesenchymal stem cells (MSCs) are known to support the characteristic properties of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow hematopoietic microenvironment. MSCs are used in coculture systems as a feeder layer for the ex vivo expansion of umbilical cord blood (CB) to increase the relatively low number of HSPCs in CB. Findings increasingly suggest that MSC-derived microvesicles (MSC-MVs) play an important role in the biological functions of their parent cells. We speculate that MSC-MVs may recapitulate the hematopoiesis-supporting effects of their parent cells. In the current study, we found MSC-MVs containing microRNAs that are involved in the regulation of hematopoiesis. We also demonstrated that MSC-MVs could improve the expansion of CB-derived mononuclear cells and CD34+ cells and generate a greater number of primitive progenitor cells in vitro. Additionally, when MSC-MVs were added to the CB-MSC coculture system, they could improve the hematopoiesis-supporting effects of MSCs. These findings highlight the role of MSC-MVs in the ex vivo expansion of CB, which may offer a promising therapeutic approach in CB transplantation. PMID:27042183

  16. Mesenchymal Stem Cell-Derived Microvesicles Support Ex Vivo Expansion of Cord Blood-Derived CD34(+) Cells.

    PubMed

    Xie, Hui; Sun, Li; Zhang, Liming; Liu, Teng; Chen, Li; Zhao, Aiqi; Lei, Qian; Gao, Fei; Zou, Ping; Li, Qiubai; Guo, An-Yuan; Chen, Zhichao; Wang, Hongxiang

    2016-01-01

    Mesenchymal stem cells (MSCs) are known to support the characteristic properties of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow hematopoietic microenvironment. MSCs are used in coculture systems as a feeder layer for the ex vivo expansion of umbilical cord blood (CB) to increase the relatively low number of HSPCs in CB. Findings increasingly suggest that MSC-derived microvesicles (MSC-MVs) play an important role in the biological functions of their parent cells. We speculate that MSC-MVs may recapitulate the hematopoiesis-supporting effects of their parent cells. In the current study, we found MSC-MVs containing microRNAs that are involved in the regulation of hematopoiesis. We also demonstrated that MSC-MVs could improve the expansion of CB-derived mononuclear cells and CD34(+) cells and generate a greater number of primitive progenitor cells in vitro. Additionally, when MSC-MVs were added to the CB-MSC coculture system, they could improve the hematopoiesis-supporting effects of MSCs. These findings highlight the role of MSC-MVs in the ex vivo expansion of CB, which may offer a promising therapeutic approach in CB transplantation. PMID:27042183

  17. Studies of Expansive Learning: Foundations, Findings and Future Challenges

    ERIC Educational Resources Information Center

    Engestrom, Yrjo; Sannino, Annalisa

    2010-01-01

    The paper examines studies based on the theory of expansive learning, formulated in 1987. In recent years the theory has been used in a wide variety of studies and interventions. The theory builds on foundational ideas put forward by Vygotsky, Leont'ev, Il'enkov, and Davydov, key figures in the Russian school of cultural-historical activity…

  18. Ab-initio study of thermal expansion in pure graphene

    NASA Astrophysics Data System (ADS)

    Mann, Sarita; Rani, Pooja; Kumar, Ranjan; Jindal, V. K.

    2016-05-01

    Graphene is a zero band gap semiconductor with exceptionally high thermal conductivity. The electronic properties having been studied, therole of phonon in contributing to thermal expansion, thermal conductivity and other thermodynamic properties, is required to be investigated. This paper focuses more on thermal expansion. Some others results like phonon dispersion, Grüneisenparameters and bulk modulus,which are essential to estimation of thermal expansion, are also presented. The dynamical matrix was calculated using VASP code using both DFT and DFPTand the phonon frequencies were calculated using phonopy code under harmonic approximation. The linear thermal expansion coefficient of graphene is found to be strongly dependent on temperature but remains negative upto 470 K and positive thereafter, with a room temperature value of -1.44×10-6. The negative expansion coefficient is very interesting and is found to be in conformity with experimental as well as with recent theoretical estimates. There is only qualitative agreement of our results with experimental data and motivates further investigation, primarily on the high negative values of Grüneisen parameters.

  19. Collisionless expansion of pulsed radio frequency plasmas. II. Parameter study

    NASA Astrophysics Data System (ADS)

    Schröder, T.; Grulke, O.; Klinger, T.; Boswell, R. W.; Charles, C.

    2016-01-01

    The plasma parameter dependencies of the dynamics during the expansion of plasma are studied with the use of a versatile particle-in-cell simulation tailored to a plasma expansion experiment [Schröder et al., J. Phys. D: Appl. Phys. 47, 055207 (2014); Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The plasma expansion into a low-density ambient plasma features a propagating ion front that is preceding a density plateau. It has been shown that the front formation is entangled with a wave-breaking mechanism, i.e., an ion collapse [Sack and Schamel, Plasma Phys. Controlled Fusion 27, 717 (1985); Sack and Schamel, Phys. Lett. A 110, 206 (1985)], and the launch of an ion burst [Schröder et al., Phys. Plasmas 23, 013511 (2016)]. The systematic parameter study presented in this paper focuses on the influence on this mechanism its effect on the maximum velocity of the ion front and burst. It is shown that, apart from the well known dependency of the front propagation on the ion sound velocity, it also depends sensitively on the density ratio between main and ambient plasma density. The maximum ion velocity depends further on the initial potential gradient, being mostly influenced by the plasma density ratio in the source and expansion regions. The results of the study are compared with independent numerical studies.

  20. Low-income residents in three states view Medicaid as equal to or better than private coverage, support expansion.

    PubMed

    Epstein, Arnold M; Sommers, Benjamin D; Kuznetsov, Yelena; Blendon, Robert J

    2014-11-01

    Expansion of Medicaid under the Affordable Care Act to millions of low-income adults has been controversial, yet little is known about what these Americans themselves think about Medicaid. We conducted a telephone survey in late 2013 of nearly 3,000 low-income adults in three Southern states--Arkansas, Kentucky, and Texas--that have adopted different approaches to the options for expansion. Nearly 80 percent of our sample in all three states favored Medicaid expansion, and approximately two-thirds of uninsured respondents said that they planned to apply for either Medicaid or subsidized private coverage in 2014. Yet awareness of their state's actual expansion plans was low. Most viewed having Medicaid as better than being uninsured and at least as good as private insurance in overall quality and affordability. While the debate over Medicaid expansion continues, support for expansion is strong among low-income adults, and the perceived quality of Medicaid coverage is high. PMID:25298540

  1. Study of expansion tube problems with phase transition

    NASA Astrophysics Data System (ADS)

    Goncalves, E.; Zeidan, D.

    2012-09-01

    In this work, a compressible multiphase one-fluid Euler solver has been developed to study one-dimensional expansion problems with cavitation process. A new model for the mass transfer between phases is proposed, and its efficiency in predicting phase transition is evaluated. Numerical simulations are compared with reference solutions computed with the two-fluid models type. The results suggest that the present model exhibits good robustness and accuracy.

  2. Numerical Studies of Electrode Plasma Formation and Expansion in High Power Charged Particle Beam Diodes

    NASA Astrophysics Data System (ADS)

    Rittersdorf, I. M.; Swanekamp, S. B.; Richardson, A. S.; Allen, R. J.; Schumer, J. W.

    2014-10-01

    High-power diodes that generate intense electron beams are useful in many applications, such as producing x-rays for flash radiography and nuclear weapon effects simulations. Desorption and ionization of gases from electrodes can form a plasma during operation. Expansion of this plasma into the gap leads to a short circuit, which limits the radiation production. It is difficult for particle-in-cell codes to model the surface physics or the subsequent expansion of the plasma. NRL is beginning a multi-year research effort to study such plasmas. This paper will summarize the relevant literature on plasma formation in high-power diodes with a goal of developing dynamic models that describe the formation and expansion of these plasmas that are suitable for PIC codes. This work was supported by the NRL Basic and Applied Research Program.

  3. Lack of C9ORF72 coding mutations supports a gain of function for repeat expansions in ALS

    PubMed Central

    Harms, Matthew B.; Cady, Janet; Zaidman, Craig; Cooper, Paul; Bali, Taha; Allred, Peggy; Cruchaga, Carlos; Baughn, Michael; Pestronk, Alan; Goate, Alison; Ravits, John; Baloh, Robert H.

    2013-01-01

    Hexanucleotide repeat expansions in C9ORF72 are a common cause of familial and apparently sporadic amyotrophic lateral sclerosis (ALS) and frontal temporal dementia (FTD). The mechanism by which expansions cause neurodegeneration is unknown, but current evidence supports both loss-of-function and gain-of-function mechanisms. We used pooled next-generation sequencing of the C9ORF72 gene in 389 ALS patients to look for traditional loss-of-function mutations. Although rare variants were identified, none were likely to be pathogenic, suggesting that mutations other than the repeat expansion are not a common cause of ALS, and providing supportive evidence for a gain-of-function mechanism. We also show by repeat-primed PCR genotyping that the C9ORF72 expansion frequency varies by geographical region within the United States, with an unexpectedly high frequency in the Mid-West. Finally we also show evidence of somatic instability of the expansion size by Southern blot, with the largest expansions occurring in brain tissue. PMID:23597494

  4. The emergence of nonbulk properties in supported metal clusters: negative thermal expansion and atomic disorder in Pt nanoclusters supported on gamma-Al2O3.

    PubMed

    Sanchez, Sergio I; Menard, Laurent D; Bram, Ariella; Kang, Joo H; Small, Matthew W; Nuzzo, Ralph G; Frenkel, Anatoly I

    2009-05-27

    The structural dynamics-cluster size and adsorbate-dependent thermal behaviors of the metal-metal (M-M) bond distances and interatomic order-of Pt nanoclusters supported on a gamma-Al(2)O(3) are described. Data from scanning transmission electron microscopy (STEM) and X-ray absorption spectroscopy (XAS) studies reveal that these materials possess a dramatically nonbulklike nature. Under an inert atmosphere small, subnanometer Pt/gamma-Al(2)O(3) clusters exhibit marked relaxations of the M-M bond distances, negative thermal expansion (NTE) with an average linear thermal expansion coefficient alpha = (-2.4 +/- 0.4) x 10(-5) K(-1), large static disorder and dynamical bond (interatomic) disorder that is poorly modeled within the constraints of classical theory. The data further demonstrate a significant temperature-dependence to the electronic structure of the Pt clusters, thereby suggesting the necessity of an active model to describe the cluster/support interactions mediating the cluster's dynamical structure. The quantitative dependences of these nonbulklike behaviors on cluster size (0.9 to 2.9 nm), ambient atmosphere (He, 4% H(2) in He or 20% O(2) in He) and support identity (gamma-Al(2)O(3) or carbon black) are systematically investigated. We show that the nonbulk structural, electronic and dynamical perturbations are most dramatically evidenced for the smallest clusters. The adsorption of hydrogen on the clusters leads to an increase of the Pt-Pt bondlengths (due to a lifting of the surface relaxation) and significant attenuation of the disorder present in the system. Oxidation of these same clusters has the opposite effect, leading to an increase in Pt-Pt bond strain and subsequent enhancement in nonbulklike thermal properties. The structural and electronic properties of Pt nanoclusters supported on carbon black contrast markedly with those of the Pt/gamma-Al(2)O(3) samples in that neither NTE nor comparable levels of atomic disorder are observed. The Pt

  5. 77 FR 65195 - Announcement of the Award of Four Single-Source Program Expansion Supplement Grants To Support...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-25

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Administration for Children and Families Announcement of the Award of Four Single-Source Program Expansion Supplement Grants To Support Activities Associated With the Tribal Early...

  6. Experimental studies of gas-particle mixtures under sudden expansion

    NASA Astrophysics Data System (ADS)

    Zunino, Heather; Adrian, Ronald; Clarke, Amanda; Arizona State University Collaboration; University of Florida Collaboration

    2015-11-01

    High-speed video cameras and pressure sensors were used to capture the movement of a particle bed due to a passing expansion fan created by a diaphragm burst in a shock tube. The particle bed is placed on the high-pressure side (p4) of the shock tube. Once the diaphragm bursts, it expands upward into the low-pressure region (p1). Several interesting structures are captured and examined, including instabilities located at the top surface of the particle bed and particle vacant regions within the bed. These features are discussed along with their relevance to the spikes of material seen radially ejected outward during a cylindrical explosion. The characteristics of this flow are compared for several different pressure regimes. Two-dimensional and three-dimensional Fourier analyses are used to further explore and measure the frequency of the features imaged. Supported by the U.S. Department of Energy, National Nuclear Security Administration, Advanced Simulation and Computing Program, as a Cooperative Agreement under the Predictive Science and Academic Alliance Program, under Contract No. DE-NA0002378.

  7. Study on Expansion of Convolutional Compactors over Galois Field

    NASA Astrophysics Data System (ADS)

    Arai, Masayuki; Fukumoto, Satoshi; Iwasaki, Kazuhiko

    Convolutional compactors offer a promising technique of compacting test responses. In this study we expand the architecture of convolutional compactor onto a Galois field in order to improve compaction ratio as well as reduce X-masking probability, namely, the probability that an error is masked by unknown values. While each scan chain is independently connected by EOR gates in the conventional arrangement, the proposed scheme treats q signals as an element over GF(2q), and the connections are configured on the same field. We show the arrangement of the proposed compactors and the equivalent expression over GF(2). We then evaluate the effectiveness of the proposed expansion in terms of X-masking probability by simulations with uniform distribution of X-values, as well as reduction of hardware overheads. Furthermore, we evaluate a multi-weight arrangement of the proposed compactors for non-uniform X distributions.

  8. Feasibility Study for Expansion of Child Development Center.

    ERIC Educational Resources Information Center

    Fitch, Naomi

    This document contains recommendations and the rationale for expansion of existing child care development center facilities at San Joaquin Delta College. Such expansion, in addition to providing immediate child care to children of parents enrolled at the college, would provide vocational training and in-service training opportunities, and would…

  9. Endothelin-1 supports clonal derivation and expansion of cardiovascular progenitors derived from human embryonic stem cells

    PubMed Central

    Soh, Boon-Seng; Ng, Shi-Yan; Wu, Hao; Buac, Kristina; Park, Joo-Hye C.; Lian, Xiaojun; Xu, Jiejia; Foo, Kylie S.; Felldin, Ulrika; He, Xiaobing; Nichane, Massimo; Yang, Henry; Bu, Lei; Li, Ronald A.; Lim, Bing; Chien, Kenneth R.

    2016-01-01

    Coronary arteriogenesis is a central step in cardiogenesis, requiring coordinated generation and integration of endothelial cell and vascular smooth muscle cells. At present, it is unclear whether the cell fate programme of cardiac progenitors to generate complex muscular or vascular structures is entirely cell autonomous. Here we demonstrate the intrinsic ability of vascular progenitors to develop and self-organize into cardiac tissues by clonally isolating and expanding second heart field cardiovascular progenitors using WNT3A and endothelin-1 (EDN1) human recombinant proteins. Progenitor clones undergo long-term expansion and differentiate primarily into endothelial and smooth muscle cell lineages in vitro, and contribute extensively to coronary-like vessels in vivo, forming a functional human–mouse chimeric circulatory system. Our study identifies EDN1 as a key factor towards the generation and clonal derivation of ISL1+ vascular intermediates, and demonstrates the intrinsic cell-autonomous nature of these progenitors to differentiate and self-organize into functional vasculatures in vivo. PMID:26952167

  10. Endothelin-1 supports clonal derivation and expansion of cardiovascular progenitors derived from human embryonic stem cells.

    PubMed

    Soh, Boon-Seng; Ng, Shi-Yan; Wu, Hao; Buac, Kristina; Park, Joo-Hye C; Lian, Xiaojun; Xu, Jiejia; Foo, Kylie S; Felldin, Ulrika; He, Xiaobing; Nichane, Massimo; Yang, Henry; Bu, Lei; Li, Ronald A; Lim, Bing; Chien, Kenneth R

    2016-01-01

    Coronary arteriogenesis is a central step in cardiogenesis, requiring coordinated generation and integration of endothelial cell and vascular smooth muscle cells. At present, it is unclear whether the cell fate programme of cardiac progenitors to generate complex muscular or vascular structures is entirely cell autonomous. Here we demonstrate the intrinsic ability of vascular progenitors to develop and self-organize into cardiac tissues by clonally isolating and expanding second heart field cardiovascular progenitors using WNT3A and endothelin-1 (EDN1) human recombinant proteins. Progenitor clones undergo long-term expansion and differentiate primarily into endothelial and smooth muscle cell lineages in vitro, and contribute extensively to coronary-like vessels in vivo, forming a functional human-mouse chimeric circulatory system. Our study identifies EDN1 as a key factor towards the generation and clonal derivation of ISL1(+) vascular intermediates, and demonstrates the intrinsic cell-autonomous nature of these progenitors to differentiate and self-organize into functional vasculatures in vivo. PMID:26952167

  11. A Study of Two-Term Unit Fraction Expansions via Geometric Approach

    ERIC Educational Resources Information Center

    Man, Yiu-Kwong

    2009-01-01

    In this article, we report a study of two-term unit fraction expansions using a geometric approach. It provides us insight on how to find all two-term unit fraction expansions and identify the property of the expansions with smallest maximal denominators, for a given unit fraction. These findings will be useful to lecturers or teachers involved in…

  12. Zambia : long-term generation expansion study - executive summary.

    SciTech Connect

    Conzelmann, G.; Koritarov, V.; Buehring, W.; Veselka, T.; Decision and Information Sciences

    2008-02-28

    The objective of this study is to analyze possible long-term development options of the Zambian electric power system in the period up to 2015. The analysis involved the hydro operations studies of the Zambezi river basin and the systems planning studies for the least-cost generation expansion planning. Two well-known and widely accepted computer models were used in the analysis: PC-VALORAGUA model for the hydro operations and optimization studies and the WASP-III Plus model for the optimization of long-term system development. The WASP-III Plus model is a part of the Argonne National Laboratory's Energy and Power Evaluation Model (ENPEP). The analysis was conducted in close collaboration with the Zambia Electricity Supply Corporation (ZESCO). On the initiative from The World Bank, the sponsor of the study, ZESCO formed a team of experts that participated in the analysis and were trained in the use of computer models. Both models were transferred to ZESCO free of charge and installed on several computers in the ZESCO corporate offices in Lusaka. In September-October 1995, two members of the ZESCO National Team participated in a 4-week training course at Argonne National Laboratory near Chicago, U.S.A., focusing on the long-term system expansion planning using the WASP and VALORAGUA models. The hydropower operations studies were performed for the whole Zambezi river basin, including the full installation of the Kariba power station, and the Cahora Bassa hydro power station in Mozambique. The analysis also included possible future projects such as Itezhi-Tezhi, Kafue Gorge Lower, and Batoka Gorge power stations. As hydropower operations studies served to determine the operational characteristics of the existing and future hydro power plants, it was necessary to simulate the whole Zambezi river basin in order to take into account all interactions and mutual influences between the hydro power plants. In addition, it allowed for the optimization of reservoir management

  13. Transverse changes in lateral and medial aspects of palatal rugae after mid palatal expansion: A pilot study

    PubMed Central

    Kapoor, Priyanka; Miglani, Ragini

    2015-01-01

    Introduction: Palatal rugae has established role in forensic identification of an individual due to its stability in growth as well as orthodontic treatment. However effect of orthodontic mid-palatal expansion on rugae stability still requires further investigation. Hence, this study was aimed at evaluating the stability of palatal rugae in transverse dimension in adolescent patients of mid-palatal expansion. Materials and Methods: The study sample consists of 14 subjects (10F,4M, age 12.4 ± 2.0 years) with transverse maxillary constriction, treated with bonded and banded rapid maxillary expansion (RME) appliance. 1st to 3rd rugae on pre- and post-expansion casts were recorded synchronously. Inter-medial and inter-lateral rugae distance were measured with digital calipers to record the transverse positional rugae changes. Results: There was a statistically significant (p < 0.05) increase in values after expansion between medial aspects of 2nd (p = 0.002) and 3rd rugae (p = 0.005) and lateral aspects of 1st (p = 0.015), 2nd (p = 0.006) and 3rd (p = 0.001) rugae. The transverse changes were recorded in the order of 3rd rugae >2nd rugae >1st rugae. Conclusion: This pilot study does not support stability of medial and lateral ruga points of 2nd and 3rd primary rugae for forensic identification in individuals treated with mid palatal expansion. PMID:25709313

  14. Phylogenetic Analysis Supports a Link between DUF1220 Domain Number and Primate Brain Expansion.

    PubMed

    Zimmer, Fabian; Montgomery, Stephen H

    2015-08-01

    The expansion of DUF1220 domain copy number during human evolution is a dramatic example of rapid and repeated domain duplication. Although patterns of expression, homology, and disease associations suggest a role in cortical development, this hypothesis has not been robustly tested using phylogenetic methods. Here, we estimate DUF1220 domain counts across 12 primate genomes using a nucleotide Hidden Markov Model. We then test a series of hypotheses designed to examine the potential evolutionary significance of DUF1220 copy number expansion. Our results suggest a robust association with brain size, and more specifically neocortex volume. In contradiction to previous hypotheses, we find a strong association with postnatal brain development but not with prenatal brain development. Our results provide further evidence of a conserved association between specific loci and brain size across primates, suggesting that human brain evolution may have occurred through a continuation of existing processes. PMID:26112965

  15. Phylogenetic Analysis Supports a Link between DUF1220 Domain Number and Primate Brain Expansion

    PubMed Central

    Zimmer, Fabian; Montgomery, Stephen H.

    2015-01-01

    The expansion of DUF1220 domain copy number during human evolution is a dramatic example of rapid and repeated domain duplication. Although patterns of expression, homology, and disease associations suggest a role in cortical development, this hypothesis has not been robustly tested using phylogenetic methods. Here, we estimate DUF1220 domain counts across 12 primate genomes using a nucleotide Hidden Markov Model. We then test a series of hypotheses designed to examine the potential evolutionary significance of DUF1220 copy number expansion. Our results suggest a robust association with brain size, and more specifically neocortex volume. In contradiction to previous hypotheses, we find a strong association with postnatal brain development but not with prenatal brain development. Our results provide further evidence of a conserved association between specific loci and brain size across primates, suggesting that human brain evolution may have occurred through a continuation of existing processes. PMID:26112965

  16. Archaeological Support for the Three-Stage Expansion of Modern Humans across Northeastern Eurasia and into the Americas

    PubMed Central

    Hamilton, Marcus J.; Buchanan, Briggs

    2010-01-01

    Background Understanding the dynamics of the human range expansion across northeastern Eurasia during the late Pleistocene is central to establishing empirical temporal constraints on the colonization of the Americas [1]. Opinions vary widely on how and when the Americas were colonized, with advocates supporting either a pre-[2] or post-[1], [3], [4], [5], [6] last glacial maximum (LGM) colonization, via either a land bridge across Beringia [3], [4], [5], a sea-faring Pacific Rim coastal route [1], [3], a trans-Arctic route [4], or a trans-Atlantic oceanic route [5]. Here we analyze a large sample of radiocarbon dates from the northeast Eurasian Upper Paleolithic to identify the origin of this expansion, and estimate the velocity of colonization wave as it moved across northern Eurasia and into the Americas. Methodology/Principal Findings We use diffusion models [6], [7] to quantify these dynamics. Our results show the expansion originated in the Altai region of southern Siberia ∼46kBP , and from there expanded across northern Eurasia at an average velocity of 0.16 km per year. However, the movement of the colonizing wave was not continuous but underwent three distinct phases: 1) an initial expansion from 47-32k calBP; 2) a hiatus from ∼32-16k calBP, and 3) a second expansion after the LGM ∼16k calBP. These results provide archaeological support for the recently proposed three-stage model of the colonization of the Americas [8], [9]. Our results falsify the hypothesis of a pre-LGM terrestrial colonization of the Americas and we discuss the importance of these empirical results in the light of alternative models. Conclusions/Significance Our results demonstrate that the radiocarbon record of Upper Paleolithic northeastern Eurasia supports a post-LGM terrestrial colonization of the Americas falsifying the proposed pre-LGM terrestrial colonization of the Americas. We show that this expansion was not a simple process, but proceeded in three phases, consistent

  17. Study on Expansion Process of EDM Arc Plasma

    NASA Astrophysics Data System (ADS)

    Natsu, Wataru; Shimoyamada, Mayumi; Kunieda, Masanori

    In order to understand the phenomena of electrical discharge machining (EDM), the characteristics of transition arc plasma in EDM were investigated. The arc plasma was directly observed with a high speed video camera. In addition, to learn more about arc plasma expansion, plasma temperature was measured by spectroscopy. The arc plasma temperature was obtained by measuring the radiant fluxes of two different wavelengths from the arc plasma and applying the line pair method. Furthermore, a new expansion model for EDM arc plasma was proposed based on the observations, and validated by comparing experimental and computed results of the discharge crater.

  18. Matrixed business support comparison study.

    SciTech Connect

    Parsons, Josh D.

    2004-11-01

    The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.

  19. A Comparative Study of Three Types of Rapid Maxillary Expansion Devices in Surgically Assisted Maxillary Expansion: A Finite Element Study

    PubMed Central

    Singaraju, Gowri Sankar; Chembeti, Dhyanisree; Mandava, Prasad; Reddy, V Karunakar; Shetty, Sharath Kumar; George, Suja Ani

    2015-01-01

    Objectives: The aim of this study was to analyze the displacement pattern and stress distribution during surgically assisted rapid maxillary expansion (RME) with three different types of RME devices by constructing a finite element model. Materials and Methods: A finite element model is constructed from the computerized tomography scans. According to the type of RME device, 3 groups were simulated on this mesh model. The experimental groups were as follows; Group I (tooth borne appliance), Group II (bone borne appliance), and Group III (hybrid appliance). A Le fort I osteotomy with bilateral pterygomaxillary disjunction and midpalatal split osteotomy cuts were incorporated in all the groups. The displacement pattern and stress distribution for each 1 mm of activation of appliance up to 10 mm is noted and analyzed. The data were analyzed using Student’s t-test, Analysis of Variance and Duncan new multiple range test. Results: Tooth borne appliance has more rotational tendencies. The bone borne and the hybrid appliance exhibited similar stress patterns for the dissipation of the forces produced by RME appliances. The pivoting effect decreased with the hybrid and the bone borne appliance and can be utilized in patient with hyper divergent growth. Conclusion: The pivoting effect is least with the hybrid appliances. PMID:26435615

  20. Thermal expansion coefficient of a water-supported perfluoro-n-eicosane monolayer

    SciTech Connect

    Huang, Z.; Acero, A.A.; Lei, N.; Rice, S.A.; Schlossman, M.L. |; Zhang, Z.

    1995-07-01

    We report the results of grazing incidence X-ray diffraction studies, as a function of temperature, of monolayers of perfluoro-n-eicosane. The experiments were undertaken to test the suggestion that there is a phase transition in this monolayer between 20 and 25{degree}C, in analogy with the transition which occurs in Teflon at about the same temperature. The issue is of importance with respect to determining whether description of the properties of a monolayer requires consideration of only the obvious quasi two dimensional character of the monolayer or requires inclusion of its three dimensional character. Our results do not support the existence of the suggested transition. 7 refs., 4 figs.

  1. LED phototherapy on midpalatal suture after rapid maxilla expansion: a Raman spectroscopic study

    NASA Astrophysics Data System (ADS)

    Rosa, Cristiane B.; Habib, Fernando Antonio L.; de Araújo, Telma M.; dos Santos, Jean N.; Cangussu, Maria Cristina T.; Barbosa, Artur Felipe S.; de Castro, Isabele Cardoso V.; Soares, Luiz Guilherme P.; Pinheiro, Antonio L. B.

    2015-03-01

    A quick bone formation after maxillary expansion would reduce treatment timeand the biomodulating effects of LED light could contribute for it. The aim of this study was to analyze the effect of LED phototherapy on the acceleration of bone formation at the midpalatal suture after maxilla expansion. Thirty rats divided into 6 groups were used on the study at 2 time points - 7 days: Control; Expansion; and Expansion + LED; and 14 days: Expansion; Expansion + LED in the first week; Expansion and LED in the first and second weeks. LED irradiation occurred at every 48 h during 2 weeks. Expansion was accomplished using a spatula and maintained with a triple helicoid of 0.020" stainless steel orthodontic wire. A LED light (λ850 ± 10nm, 150mW ± 10mW, spot of 0.5cm2, t=120 sec, SAEF of 18J/cm2) was applied in one point in the midpalatal suture immediately behind the upper incisors. Near infrared Raman spectroscopic analysis of the suture region was carried and data submitted to statistical analyzes (p≤0.05). Raman spectrum analysis demonstrated that irradiation increased hydroxyapatite in the midpalatal suture after expansion. The results of this indicate that LED irradiation; have a positive biomodulation contributing to the acceleration of bone formation in the midpalatal suture after expansion procedure.

  2. Does Educational Expansion Encourage Female Workforce Participation? A Study of the 1968 Reform in Taiwan

    ERIC Educational Resources Information Center

    Tsai, Wehn-Jyuan; Liu, Jin-Tan; Chou, Shin-Yi; Thornton, Robert

    2009-01-01

    Between 1968 and 1973 the Taiwanese government undertook the most extensive expansion on record of the public junior high school system in Taiwan. This study analyzes the effects of the 1968 education reform and subsequent high school expansion on gender disparities in employment generally, as well in different sectors and classes of employment.…

  3. Dynamics of mtDNA introgression during species range expansion: insights from an experimental longitudinal study

    PubMed Central

    Mastrantonio, V.; Porretta, D.; Urbanelli, S.; Crasta, G.; Nascetti, G.

    2016-01-01

    Introgressive hybridization represents one of the long-lasting debated genetic consequences of species range expansion. Mitochondrial DNA has been shown to heavily introgress between interbreeding animal species that meet in new sympatric areas and, often, asymmetric introgression from local to the colonizing populations has been observed. Disentangling among the evolutionary and ecological processes that might shape this pattern remains difficult, because they continuously act across time and space. In this context, long-term studies can be of paramount importance. Here, we investigated the dynamics of mitochondrial introgression between two mosquito species (Aedes mariae and Ae. zammitii ) during a colonization event that started in 1986 after a translocation experiment. By analyzing 1,659 individuals across 25 years, we showed that introgression occurred earlier and at a higher frequency in the introduced than in the local species, showing a pattern of asymmetric introgression. Throughout time, introgression increased slowly in the local species, becoming reciprocal at most sites. The rare opportunity to investigate the pattern of introgression across time during a range expansion along with the characteristics of our study-system allowed us to support a role of demographic dynamics in determining the observed introgression pattern. PMID:27460445

  4. Dynamics of mtDNA introgression during species range expansion: insights from an experimental longitudinal study.

    PubMed

    Mastrantonio, V; Porretta, D; Urbanelli, S; Crasta, G; Nascetti, G

    2016-01-01

    Introgressive hybridization represents one of the long-lasting debated genetic consequences of species range expansion. Mitochondrial DNA has been shown to heavily introgress between interbreeding animal species that meet in new sympatric areas and, often, asymmetric introgression from local to the colonizing populations has been observed. Disentangling among the evolutionary and ecological processes that might shape this pattern remains difficult, because they continuously act across time and space. In this context, long-term studies can be of paramount importance. Here, we investigated the dynamics of mitochondrial introgression between two mosquito species (Aedes mariae and Ae. zammitii ) during a colonization event that started in 1986 after a translocation experiment. By analyzing 1,659 individuals across 25 years, we showed that introgression occurred earlier and at a higher frequency in the introduced than in the local species, showing a pattern of asymmetric introgression. Throughout time, introgression increased slowly in the local species, becoming reciprocal at most sites. The rare opportunity to investigate the pattern of introgression across time during a range expansion along with the characteristics of our study-system allowed us to support a role of demographic dynamics in determining the observed introgression pattern. PMID:27460445

  5. Experimental study of novel microactuator based on photothermal expansion

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Zhang, Dong-Xian; Zhang, Hai-Jun

    2008-03-01

    A novel photothermal drive method was proposed. A novel photothermal micro-actuator (PTA) was developed with this method. We introduced the deflection mechanism of the asymmetric expansive arms with different widths. When a beam of infrared laser irradiates the arms, the different increase temperature and photothermal expansion controlled by the different rates of specific surface area cause a magnified lateral deflection. A prototyping micro-actuator of 1000 μm length was manufactured by using an excimer laser micromachining system, and using polypropylene material. Experiments have been carried out to check the feasibility of deflection, with a laser diode (650 nm) as the external power source to activate the micro-actuator. The results show that the actuator can practically generate an obvious lateral deflection without considering the size or the location of the irradiated light spot strictly. The deflection status of the micro-actuator could be controlled remotely from 0 μm to 14.33 μm by changing the laser power from 0 mW to 10 mW. This kind of novel PTA is quite simple and convenient for operation. It will be quite useful for the applications in the fields of micro/nano-technology and with large displacement/actuation force and remote controlling.

  6. Thermal expansion of supported and freestanding graphene: lattice constant versus interatomic distance.

    PubMed

    Pozzo, Monica; Alfè, Dario; Lacovig, Paolo; Hofmann, Philip; Lizzit, Silvano; Baraldi, Alessandro

    2011-04-01

    By using ab initio molecular dynamics calculations, we show that even where the graphene lattice constant contracts, as previously reported for freestanding graphene below room temperature, the average carbon-carbon distance increases with temperature, in both free and supported graphene. This results in a larger corrugation at higher temperature, which can affect the interaction between graphene and the supporting substrate. For a weakly interacting system as graphene/Ir(111), we confirm the results using an experimental approach which gives direct access to interatomic distances. PMID:21517393

  7. Using Course Load Matrix Analysis To Support Departmental Planning for Enrollment Expansion. AIR 2002 Forum Paper.

    ERIC Educational Resources Information Center

    Harter, Elizabeth A.; England, Martin D.

    The planning office of a large urban university produced an induced course load matrix (ICLM) analysis to support the university's plans for undergraduate enrollment growth at its three campuses. The ICLM tables, based on the complete course histories of the 1993 entering cohort, summarize the program and course selections of a cohort of students…

  8. First Lunar Outpost support study

    NASA Technical Reports Server (NTRS)

    Bartz, Christopher; Cook, John; Rusingizandekwe, Jean-Luc

    1993-01-01

    The First Lunar Outpost (FLO) is the first manned step in the accomplishment of the Space Exploration Initiative, the Vice President's directive to NASA on the 20th anniversary of the Apollo moon landing. FLO's broad objectives are the establishment of a permanent human presence on the moon, supporting the utilization of extraterrestrial resources in a long-term, sustained program. The primary objective is to emplace and validate the first elements of a man tended outpost on the lunar surface to provide the basis for: (1) establishing, maintaining and expanding human activities and influence across the surface; (2) establishing, maintaining and enhancing human safety and productivity; (3) accommodating space transportation operations to and from the surface; (4) accommodating production of scientific information; (5) exploiting in-situ resources. Secondary objectives are: (1) to conduct local, small scale science (including life science); (2) In-situ resource utilization (ISRU) demonstrations; (3) engineering and operations tests; (4) to characterize the local environment; and (5) to explore locally. The current work is part of ongoing research at the Sasakawa International Center for Space Architecture supporting NASA's First Lunar Outpost initiative. Research at SICSA supporting the First Lunar Outpost initiative has been funded through the Space Exploration Initiatives office at Johnson Space Center. The objectives of the current study are to further develop a module concept from an evaluation of volumetric and programmatic requirements, and pursue a high fidelity design of this concept, with the intention of providing a high fidelity design mockup to research planetary design issues and evaluate future design concepts.

  9. Thermal Expansion Studies of Selected High Temperature Thermoelectric Materials

    NASA Technical Reports Server (NTRS)

    Ravi, Vilupanur; Firdosy, Samad; Caillat, Thierry; Brandon, Erik; Van Der Walde, Keith; Maricic, Lina; Sayir, Ali

    2008-01-01

    Radioisotope thermoelectric generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions and have demonstrated their reliability over an extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. System conversion efficiency for state-of-practice RTGs is about 6% and specific power less than or equal to 5.1 W/kg. Higher specific power would result in more on-board power for the same RTG mass, or less RTG mass for the same on-board power. The Jet Propulsion Laboratory has been leading, under the advanced thermoelectric converter (ATEC) project, the development of new high-temperature thermoelectric materials and components for integration into advanced, more efficient RTGs. Thermoelectric materials investigated to date include skutterudites, the Yb14MnSb11 compound, and SiGe alloys. The development of long-lived thermoelectric couples based on some of these materials has been initiated and is assisted by a thermo-mechanical stress analysis to ensure that all stresses under both fabrication and operation conditions will be within yield limits for those materials. Several physical parameters are needed as input to this analysis. Among those parameters, the coefficient of thermal expansion (CTE) is critically important. Thermal expansion coefficient measurements of several thermoelectric materials under consideration for ATEC are described in this paper. The stress response at the interfaces in material stacks subjected to changes in temperature is discussed, drawing on work from the literature and project-specific tools developed here. The degree of CTE mismatch and the associated effect on the formation of stress is highlighted.

  10. Thermal Expansion Studies of Selected High-Temperature Thermoelectric Materials

    NASA Astrophysics Data System (ADS)

    Ravi, Vilupanur; Firdosy, Samad; Caillat, Thierry; Brandon, Erik; van der Walde, Keith; Maricic, Lina; Sayir, Ali

    2009-07-01

    Radioisotope thermoelectric generators (RTGs) generate electrical power by converting the heat released from the nuclear decay of radioactive isotopes (typically plutonium-238) into electricity using a thermoelectric converter. RTGs have been successfully used to power a number of space missions and have demonstrated their reliability over an extended period of time (tens of years) and are compact, rugged, radiation resistant, scalable, and produce no noise, vibration or torque during operation. System conversion efficiency for state-of-practice RTGs is about 6% and specific power ≤5.1 W/kg. A higher specific power would result in more onboard power for the same RTG mass, or less RTG mass for the same onboard power. The Jet Propulsion Laboratory has been leading, under the advanced thermoelectric converter (ATEC) project, the development of new high-temperature thermoelectric materials and components for integration into advanced, more efficient RTGs. Thermoelectric materials investigated to date include skutterudites, the Yb14MnSb11 compound, and SiGe alloys. The development of long-lived thermoelectric couples based on some of these materials has been initiated and is assisted by a thermomechanical stress analysis to ensure that all stresses under both fabrication and operation conditions will be within yield limits for those materials. Several physical parameters are needed as input to this analysis. Among those parameters, the coefficient of thermal expansion (CTE) is critically important. Thermal expansion coefficient measurements of several thermoelectric materials under consideration for ATEC are described in this paper. The stress response at the interfaces in material stacks subjected to changes in temperature is discussed, drawing on work from the literature and project-specific tools developed here. The degree of CTE mismatch and the associated effect on the formation of stress is highlighted.

  11. Lateral expansion of a laser-supported detonation wave in a gas.

    NASA Technical Reports Server (NTRS)

    Howe, J. T.

    1972-01-01

    A model satisfying the conditions in the burnt (ionized) and ambient undisturbed gases is presented for the two-dimensional case of the absorption wave resulting from the interaction of a laser beam with the plasma it generates in the gas through which the beam propagates. The flowfield of the rarefaction wave resulting from the laser-supported detonation is discussed, along with the computed shock and flow deflection angles.

  12. [Matrix Support: a bibliographical study].

    PubMed

    Iglesias, Alexandra; Avellar, Luziane Zacché

    2014-09-01

    This article presents a bibliographical review of matrix support in mental health. A search was conducted in the Virtual Health Library and the LILACS, SciELO and Google Scholar databases using the key words: "matrix support in mental health." Fourteen articles were located with the desired characteristics, which indicates that only a restricted number of publications are in circulation. The articles were analyzed with respect to their structural and methodological aspects, which revealed the absolute predominance of the use of qualitative methods and health professionals as the target research population. The same articles were then analyzed for their theoretical discussions. Among other issues, the importance of matrix support to enhance the primary health care teams provided to people suffering from psychic distress is highlighted. However, there is still considerable confusion regarding the proposal of the matrix support and shared responsibilities between teams of reference and mental health professionals, which emphasizes the need for training of these professionals, as well as better coordination and organization of the mental health care network. PMID:25184584

  13. Electricity system expansion studies to consider uncertainties and interactions in restructured markets

    NASA Astrophysics Data System (ADS)

    Jin, Shan

    This dissertation concerns power system expansion planning under different market mechanisms. The thesis follows a three paper format, in which each paper emphasizes a different perspective. The first paper investigates the impact of market uncertainties on a long term centralized generation expansion planning problem. The problem is modeled as a two-stage stochastic program with uncertain fuel prices and demands, which are represented as probabilistic scenario paths in a multi-period tree. Two measurements, expected cost (EC) and Conditional Value-at-Risk (CVaR), are used to minimize, respectively, the total expected cost among scenarios and the risk of incurring high costs in unfavorable scenarios. We sample paths from the scenario tree to reduce the problem scale and determine the sufficient number of scenarios by computing confidence intervals on the objective values. The second paper studies an integrated electricity supply system including generation, transmission and fuel transportation with a restructured wholesale electricity market. This integrated system expansion problem is modeled as a bi-level program in which a centralized system expansion decision is made in the upper level and the operational decisions of multiple market participants are made in the lower level. The difficulty of solving a bi-level programming problem to global optimality is discussed and three problem relaxations obtained by reformulation are explored. The third paper solves a more realistic market-based generation and transmission expansion problem. It focuses on interactions among a centralized transmission expansion decision and decentralized generation expansion decisions. It allows each generator to make its own strategic investment and operational decisions both in response to a transmission expansion decision and in anticipation of a market price settled by an Independent System Operator (ISO) market clearing problem. The model poses a complicated tri-level structure

  14. Expansion of the MANAGE database with forest and drainage studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The “Measured Annual Nutrient loads from AGricultural Environments” (MANAGE) database was published in 2006 to expand an early 1980’s compilation of nutrient export (load) data from agricultural land uses at the field or farm spatial scale. Then in 2008, MANAGE was updated with 15 additional studie...

  15. A Perturbation Expansion Method to Study Highly Correlated Spins

    SciTech Connect

    Anda, E. V.; Chiappe, G.; Busser, Carlos A; Davidovich, M. A.; Martins, G. B.; Heidrich-Meisner, F.; Dagotto, Elbio R

    2009-01-01

    This paper proposes a new numerical algorithm to study dynamical spin dependent properties of local highly correlated structures. The method consists in diagonalizing a finite cluster containing the many-body terms of the Hamil- tonian and embedding it into the rest of the system, the Em- bedding Cluster Approximation (ECA), combined with Wil- son s ideas of logarithmic discretization of the representa- tion of the Hamiltonian, the Logarithm Discretization Em- bedded Cluster Approximation (LDECA). The physics as- sociated to a dot and a side-coupled double dot connected to leads are discussed in detail.

  16. PVC makers study expansions to meet demand growth

    SciTech Connect

    Hunter, D.; Coeyman, M.

    1993-02-10

    As prospects for the polyvinyl chloride (PVC) industry continue to improve, the next batch of capacity increases is being studied. Vista Chemical (Houston) sees an opportunity to achieve what company president James R. Ball calls the lowest-cost capacity addition in the market, by debottlenecking its PVC plants at Aberdeen, MS and Oklahoma City. That would increase capacity 40%, adding 300 million lbs/year to Vista's 830 million lbs/year. US demand for PVC grew 12.5% through the first 10 months of 1992, to 7.3 billion lbs, according to the latest figures available from the Society of the Plastics Industry. Alan Bailey, Oxy-Chem's executive v.p./polymers and plastics, predicts a good demand year in 1993 - better even than 1992, driven by an upward trend in housing starts and a recovering economy.

  17. Experimental study of penetration-cavity expansion soil bioturbation models using miniature cone penetrometers

    NASA Astrophysics Data System (ADS)

    Ruiz, Siul; Or, Dani; Schymanski, Stan

    2015-04-01

    A recently developed model of soil penetration mechanics and energetics by earthworms and plant roots is based on analogy with cone penetration and cavity expansion. Model predicted resistive forces for different geometries were tested using miniature cone penetrometers at sizes compatible with burrowing earthworms and growing roots. Experiments using cones of different radii (1.0 to 2.5 mm) and different semi-apex angles (15-300) were conducted using an apparatus enabling insertion at constant (prescribed) rates while obtaining highly resolved penetration resistance force measurements. Penetration experiments used soils at different water contents where soil mechanical parameters were determined independently using Oedometer tests under confined and unconfined conditions. Measurements were compared with predictions by analytical expressions for earthworm or root burrowing mechanics. Model predictions for the insertion force as a function of cone geometry and soil mechanical properties were in excellent agreement with cone penetration measurements. The study provides the necessary experimental confirmation to support energetic estimates of bioturbation costs in terms of soil organic carbon consumption. The study provides a better understanding of the fundamental duality nature between penetration forces and stresses and the dependency on cone angle. The measurements suggest that friction plays a relatively minor role as confirmed by experiments using recessed cones (no soil-shaft friction). Differences in application of the model to plant roots and earthworms will be discussed.

  18. 77 FR 65895 - Announcement of the Award of Four Single-Source Program Expansion Supplement Grants To Support...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ... expansion supplement grants to Tribal Maternal, Infant, and Early Childhood Home Visiting (MIECHV) grantees... expansion supplement grants to four grantees in the Tribal Maternal, Infant, and Early Childhood Home... learning grants: Head Start/Early Head Start, Tribal Child Care, and Tribal Maternal, Infant, and...

  19. Ex vivo expansion and transplantation of hematopoietic stem/progenitor cells supported by mesenchymal stem cells from human umbilical cord blood.

    PubMed

    Huang, Guo-Ping; Pan, Zhi-Jun; Jia, Bing-Bing; Zheng, Qiang; Xie, Chun-Gang; Gu, Jiang-Hong; McNiece, Ian K; Wang, Jin-Fu

    2007-01-01

    Human mesenchymal stem cells (MSCs) are multipotential and are detected in bone marrow (BM), adipose tissue, placenta, and umbilical cord blood (UCB). In this study, we examined the ability of UCB-derived MSCs (UCB-MSCs) to support ex vivo expansion of hematopoietic stem/progenitor cells (HSPCs) from UCB and the engraftment of expanded HSPCs in NOD/SCID mice. The result showed that UCB-MSCs supported the proliferation and differentiation of CD34+ cells in vitro. The number of expanded total nucleated cells (TNCs) in MSC-based culture was twofold higher than cultures without MSC (control cultures). UCB-MSCs increased the expansion capabilities of CD34+ cells, long-term culture-initiating cells (LTC-ICs), granulocyte-macrophage colony-forming cells (GM-CFCs), and high proliferative potential colony-forming cells (HPP-CFCs) compared to control cultures. The expanded HSPCs were transplanted into lethally irradiated NOD/SCID mice to assess the effects of expanded cells on hematopoietic recovery. The number of white blood cells (WBCs) in the peripheral blood of mice transplanted with expanded cells from both the MSC-based and control cultures returned to pretreatment levels at day 25 posttransplant and then decreased. The WBC levels returned to pretreatment levels again at days 45-55 posttransplant. The level of human CD45+ cell engraftment in primary recipients transplanted with expanded cells from the MSC-based cultures was significantly higher than recipients transplanted with cells from the control cultures. Serial transplantation demonstrated that the expanded cells could establish long-term engraftment of hematopoietic cells. UCB-MSCs similar to those derived from adult bone marrow may provide novel targets for cellular and gene therapy. PMID:17912949

  20. Simulation study of negative thermal expansion in yttrium tungstate Y2W3O12.

    PubMed

    Rimmer, Leila H N; Dove, Martin T

    2015-05-13

    A simulation study of negative thermal expansion in Y2W3O12 was carried out using calculations of phonon dispersion curves through the application of density functional perturbation theory. The mode eigenvectors were mapped onto flexibility models and results compared with calculations of the mode Grüneisen parameters. It was found that many lower-frequency phonons contribute to negative thermal expansion in Y2W3O12, all of which can be described in terms of rotations of effectively rigid WO4 tetrahedra and Y-O rods. The results are strikingly different from previous phonon studies of higher-symmetry materials that show negative thermal expansion. PMID:25880236

  1. Performance Support Case Studies from IBM.

    ERIC Educational Resources Information Center

    Duke-Moran, Celia; Swope, Ginger; Morariu, Janis; deKam, Peter

    1999-01-01

    Presents two case studies that show how IBM addressed performance support solutions and electronic learning. The first developed a performance support and expert coaching solution; the second applied performance support to reducing implementation time and total cost of ownership of enterprise resource planning systems. (Author/LRW)

  2. A Study of Predoctoral Student Support.

    ERIC Educational Resources Information Center

    Federal Interagency Committee on Education, Washington, DC. Student Support Study Group.

    This report of the Federal Interagency Committee on Education (FCIE) presents recommendations for expanding current federal support for graduate study. Federal agencies allocated $226.2 million for predoctoral fellowships and supported some 12.9% of the full-time graduate students in the US during the 1968-1969 school year. This support increased…

  3. Aerosol backscatter studies supporting LAWS

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry

    1989-01-01

    Optimized Royal Signals and Radar Establishment (RSRE), Laser True Airspeed System (LATAS) algorithm for low backscatter conditions was developed. The algorithm converts backscatter intensity measurements from focused continuous-wave (CW) airborne Doppler lidar into backscatter coefficients. The performance of optimized algorithm under marginal backscatter signal conditions was evaluated. The 10.6 micron CO2 aerosol backscatter climatologies were statistically analyzed. Climatologies reveal clean background aerosol mode near 10(exp -10)/kg/sq m/sr (mixing ratio units) through middle and upper troposhere, convective mode associated with planetary boundary layer convective activity, and stratospheric mode associated with volcanically-generated aerosols. Properties of clean background mode are critical to design and simulation studies of Laser Atmospheric Wind Sounder (LAWS), a MSFC facility Instrument on the Earth Observing System (Eos). Previous intercomparisons suggested correlation between aerosol backscatter at CO2 wavelength and water vapor. Field measurements of backscatter profiles with MSFC ground-based Doppler lidar system (GBDLS) were initiated in late FY-88 to coincide with independent program of local rawinsonde releases and overflights by Multi-spectral Atmospheric Mapping Sensor (MAMS), a multi-channel infrared radiometer capable of measuring horizontal and vertical moisture distributions. Design and performance simulation studies for LAWS would benefit from the existence of a relationship between backscatter and water vapor.

  4. Thermal expansion study of a "Direct Chill Casting" AlMgSi alloy

    NASA Astrophysics Data System (ADS)

    Guemini, R.; Boubertakh, A.; Hamamda, S.

    2001-03-01

    This work is concerned with the study of thermal expansion coefficient of Al-0.59 wt.% Mg- 0.88 wt.% Si-0.30 wt.% Fe-0.44 wt.% Mn alloy. The presence of the anisotropy was concluded on the basis of the thermal expansion coefficient α(T) which depends up on the two directions: radial (1) and axial (2). However α(T) measured along the axial direction (2) appeared to be inferior to the measured one along the radial direction (1) in both as-cast and homogenised alloy.

  5. STS Case Study Development Support

    NASA Technical Reports Server (NTRS)

    Rosa de Jesus, Dan A.; Johnson, Grace K.

    2013-01-01

    The Shuttle Case Study Collection (SCSC) has been developed using lessons learned documented by NASA engineers, analysts, and contractors. The SCSC provides educators with a new tool to teach real-world engineering processes with the goal of providing unique educational materials that enhance critical thinking, decision-making and problem-solving skills. During this third phase of the project, responsibilities included: the revision of the Hyper Text Markup Language (HTML) source code to ensure all pages follow World Wide Web Consortium (W3C) standards, and the addition and edition of website content, including text, documents, and images. Basic HTML knowledge was required, as was basic knowledge of photo editing software, and training to learn how to use NASA's Content Management System for website design. The outcome of this project was its release to the public.

  6. 76 FR 55732 - Public Listening Sessions Regarding the Maritime Administration's Panama Canal Expansion Study...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-08

    ... Maritime Administration Public Listening Sessions Regarding the Maritime Administration's Panama Canal... workshops regarding the expansion of the Panama Canal and the America's Marine Highway Program. The meetings... Administration (MARAD) should consider in the development of its comprehensive study of the 2014 Panama...

  7. Attitudes of County Leaders toward Expanding Adult Programs in Extension: Minnesota Expansion Study I.

    ERIC Educational Resources Information Center

    Wilson, Duane A.; And Others

    A study was conducted in Minnesota on attitudes of county leaders (commissioners, auditors, and appointed Extension committee members) on ways of expanding Extension programs. In each county data were gathered by questionnaire from at least two thirds of the leaders. Questions were asked about expansion (1) through working with other…

  8. A computational study of two-phase viscoelastic systems in a capillary tube with a sudden contraction/expansion

    NASA Astrophysics Data System (ADS)

    Muradoglu, Metin; Izbassarov, Daulet

    2015-11-01

    Two-phase viscoelastic systems are computationally studied in a pressure-driven tube with a sudden contraction and expansion using a finite-difference/front-tracking method. The effects of viscoelasticity in drop and bulk fluids are investigated including high Weissenberg and Reynolds number cases up to Wi = 100 and Re = 100 . The FENE-CR model is used to account for the fluid viscoelasticity. Extensive computations are performed to examine drop dynamics for a wide range of parameters. It is found that viscoelasticity interacts with drop interface in a non-monotonic and complicated way, and the two-phase viscoelastic systems exhibit very rich dynamics especially in the expansion region. At high Re , the drop undergoes large deformation in the contraction region followed by shape oscillations in the downstream of the expansion. For a highly viscous drop, a re-entrant cavity develops in the contraction region at the trailing edge which, in certain cases, grows and eventually causes encapsulation of ambient fluid. The re-entrant cavity formation is initiated at the entrance of the contraction and is highly influenced by the viscoelasticity. The effects of viscoelasticity are reversed in the constricted channel: Viscoelasticity in drop/continuous phase hinders/enhances format The authors are grateful to the Scientific and Technical Research Council of Turkey (TUBITAK) for the support of this research through Grant 112M181 and Turkish Academy of Sciences (TUBA).

  9. Bariatric support line: a prospective study of support line activity.

    PubMed

    McDougall, Kirsten; Segaran, Ella; Sufi, Pratik; Heath, Dugal I

    2010-03-01

    In this prospective study, we examine the workload of the North London Obesity Surgery Service Bariatric telephone support line (BTSL) and its effects on service provision. Over a 3-month period (June to August 2008), a prospective record was kept of all calls, who they were from, whether the patient was presurgery or postsurgery, the type of procedure planned or undertaken, the nature of the enquiry, and the time taken to answer the query. Seventy-five (72%) calls were related to patients who were postsurgery and 29 (28%) presurgery. Patients scheduled for or having undergone Roux-en-Y gastric bypass accounted for 46 (44%) calls; 24 (23%) were preprocedure and 22 (21%) postprocedure. Patients scheduled for or having undergone gastric banding accounted for 56 (54%) calls; five (0.5%) were preprocedure and 51 (49%) postprocedure. Patients undergoing sleeve gastrectomy accounted for two (<1%) calls. Both calls were postprocedure. The reason for the support line enquiry was psychological support in 15 (14%) patients, questions postsurgery in 26 (25%), general enquiries in 27 (26%), and clinical enquiries in 36 (36%). This study of the BTSL has allowed us to identify areas of need within our bariatric population and improve the service we deliver. The changes we have made should lead to a better use of the team's time, greater patient compliance, and satisfaction as well as reduced complaints and litigation. PMID:19711140

  10. Youth Development Program Expansion; A Study of the Use of Paraprofessionals in Youth Program Expansion and Development from Middle Class Areas and Critical Areas of St. Louis, Missouri.

    ERIC Educational Resources Information Center

    Jones, Isabel A.

    This informal study sought to determine the effectiveness of paraprofessionals in extension work dealing with the development and expansion of youth programs in disadvantaged areas of St. Louis. Program objectives were: (1) to reach more youth in educational programs sensitive to the life style of urban youth; (2) to develop new ways of recruiting…

  11. SUPPORT STUDIES IN FLUIDIZED-BED COMBUSTION

    EPA Science Inventory

    The report gives results of working in support of development studies for atmospheric and pressurized fluidized-bed coal combustion. Laboratory and process development studies are aimed at providing needed information on limestone utilization, removal of particulates and alkali m...

  12. SUPPORTIVE STUDIES IN FLUIDIZED-BED COMBUSTION

    EPA Science Inventory

    The report gives results of studies supporting the development of atmospheric and pressurized fluidized-bed combustion (FBC) of coal. It includes laboratory and bench-scale studies to provide needed information on combustion optimization, regeneration process development, solid w...

  13. Human mesenchymal and murine stromal cells support human lympho-myeloid progenitor expansion but not maintenance of multipotent haematopoietic stem and progenitor cells.

    PubMed

    Radtke, Stefan; Görgens, André; Liu, Bing; Horn, Peter A; Giebel, Bernd

    2016-02-16

    A major goal in haematopoietic stem cell (HSC) research is to define conditions for the expansion of HSCs or multipotent progenitor cells (MPPs). Since human HSCs/MPPs cannot be isolated, NOD/SCID repopulating cell (SRC) assays emerged as the standard for the quantification of very primitive haematopoietic cell. However, in addition to HSCs/MPPs, lympho-myeloid primed progenitors (LMPPs) were recently found to contain SRC activities, challenging this assay as clear HSC/MPP readout. Because our revised model of human haematopoiesis predicts that HSCs/MPPs can be identified as CD133(+)CD34(+) cells containing erythroid potentials, we investigated the potential of human mesenchymal and conventional murine stromal cells to support expansion of HSCs/MPPs. Even though all stromal cells supported expansion of CD133(+)CD34(+) progenitors with long-term myeloid and long-term lymphoid potentials, erythroid potentials were exclusively found within erythro-myeloid CD133(low)CD34(+) cell fractions. Thus, our data demonstrate that against the prevailing assumption co-cultures on human mesenchymal and murine stromal cells neither promote expansion nor maintenance of HSCs and MPPs. PMID:26818432

  14. First-principles study of negative thermal expansion in zinc oxide

    NASA Astrophysics Data System (ADS)

    Wang, Zhanyu; Wang, Fei; Wang, Lei; Jia, Yu; Sun, Qiang

    2013-08-01

    We present the first-principles calculations of vibrational and thermal properties for wurtzite and zinc-blende zinc oxide (ZnO) within DFT and quasi-harmonic approximation, especially for their negative thermal expansion (NTE) behavior. For the wurtzite and zinc-blende phases, negative thermal expansions are obtained at T < 95 K and T < 84 K, respectively. For the wurtzite structure, calculated phonon frequencies and mode Grüneisen parameters of low-energy modes are in good agreement with that determined experimentally. And the thermal expansion coefficient is found to be in good agreement with the experimental results. Like many other NTE semiconductors, detailed study of both phases shows that maximum contribution to NTE comes from low-frequency transverse acoustic modes, while for the wurtzite structure the contribution of longitudinal acoustic and lowest-energy optical modes is not ignorable. From the specific analysis of the vibration modes, we found that the negative thermal expansion in ZnO is dominated by the tension effect.

  15. Critical Issues in Supporting Self-Study

    ERIC Educational Resources Information Center

    Lunenberg, Mieke; Zwart, Rosanne; Korthagen, Fred

    2010-01-01

    In this article, we focus on an analysis of critical issues in supporting teacher educators conducting a self-study. As data, we have used the digital logbooks written by the participating teacher educators, the outcomes of the interviews we held at the end of the support process, and of a follow-up questionnaire answered by the participating…

  16. Thermal expansion in 3d-metal Prussian Blue Analogs-A survey study

    SciTech Connect

    Adak, Sourav; Daemen, Luke L.; Hartl, Monika; Williams, Darrick; Summerhill, Jennifer; Nakotte, Heinz

    2011-11-15

    We present a comprehensive study of the structural properties and the thermal expansion behavior of 17 different Prussian Blue Analogs (PBAs) with compositions M{sup II}{sub 3}[(M'){sup III}(CN){sub 6}]{sub 2}.nH{sub 2}O and M{sup II}{sub 2}[Fe{sup II}(CN){sub 6}].nH{sub 2}O, where M{sup II}=Mn, Fe, Co, Ni, Cu and Zn, (M'){sup III}=Co, Fe and n is the number of water molecules, which range from 5 to 18 for these compounds. The PBAs were synthesized via standard chemical precipitation methods, and temperature-dependent X-ray diffraction studies were performed in the temperature range between -150 deg. C (123 K) and room-temperature. The vast majority of the studied PBAs were found to crystallize in cubic structures of space groups Fm3-bar m, F4-bar 3m and Pm3-bar m. The temperature dependence of the lattice parameters was taken to compute an average coefficient of linear thermal expansion in the studied temperature range. Of the 17 compounds, 9 display negative values for the average coefficient of linear thermal expansion, which can be as large as 39.7x{sup 1}0{sup -6} K{sup -1} for Co{sub 3}[Co(CN){sub 6}]{sub 2}.12H{sub 2}O. All of the M{sup II}{sub 3}[Co{sup III}(CN){sub 6}]{sub 2}.nH{sub 2}O compounds show negative thermal expansion behavior, which correlates with the Irving-Williams series for metal complex stability. The thermal expansion behavior for the PBAs of the M{sup II}{sub 3}[Fe{sup III}(CN){sub 6}]{sub 2}.nH{sub 2}O family are found to switch between positive (for M=Mn, Co, Ni) and negative (M=Cu, Zn) behavior, depending on the choice of the metal cation (M). On the other hand, all of the M{sup II}{sub 2}[Fe{sup II}(CN){sub 6}].nH{sub 2}O compounds show positive thermal expansion behavior. - Graphical Abstract: The structure of Prussian Blue analogs (PBAs) consists of two types of metal centered octahedral units connected by cyanide ligand. Lattice and interstitial water molecules are present in these framework structures. All the PBAs of the M{sub 3

  17. Experimental study of the expansion dynamic of 9 mm Parabellum hollow point projectiles in ballistic gelatin.

    PubMed

    Bresson, F; Ducouret, J; Peyré, J; Maréchal, C; Delille, R; Colard, T; Demondion, X

    2012-06-10

    We study in this paper the expanding behaviour of hollow point 9 mm Parabellum projectiles (Hornady XTP(®) and Speer Gold Dot(®)). We defined a deformation rate that takes into account both the diameter increase and the length reduction. We plotted the behaviour of this parameter versus impact velocity (we refer to this curve as the expanding law). This expanding law has been plotted for different gelatin weight ratios and different gelatin block lengths. We completed our experiments with a set of high speed movies in order to correlate the deceleration to the state of expansion and size of the temporary cavity. Our results pointed out that full expansion is reached shortly after the projectile fully penetrates the gelatin. This result shows that the key point to accurately simulate human body interaction with a hollow point projectile is to accurately simulate the interface (skin, skull, clothes thoracic walls). Simulating accurately organs is only an issue if a quantitative comparison between penetration depths is required, but not if we only focus on the state of expansion of the projectile. By varying the gelatin parameters, we discovered that the expanding law exhibits a velocity threshold below which no expansion occurs, followed by a rather linear curve. The parameters of that expanding law (velocity threshold and line slope) vary with the gelatin parameters, but our quantitative results demonstrate that these parameters are not extremely critical. Finally, our experiments demonstrate that the knowledge of the expansion law can be a useful tool to investigate a gunshot in a human body with a semi-jacketed projectile, giving an estimation of the impact velocity and thus the shooting distance. PMID:22269130

  18. Policies for Evaluation and Regulation of Higher Education in Brazil (1995-2010), Supporting the Expansion of Private Higher Education

    ERIC Educational Resources Information Center

    Barreyro, Gladys Beatriz; Rothen, José Carlos; Santana, Andréia da Cunha Malheiros

    2014-01-01

    This paper analyzes the routes of the evaluation of higher education in Brazil, from 1995 until 2010. In 1995, during Fernando Henrique Cardoso's administration, higher education began a process of expansion through private enterprise. At that time, evaluation had a key role. The focus was the evaluation of courses conducted by the Ministry…

  19. Lunar Outpost Life Support Trade Studies

    NASA Astrophysics Data System (ADS)

    Ewert, Michael; Barta, Daniel J.; Lange, Kevin; Anderson, Molly

    Engineering trade-off studies of life support system architecture and technology options were conducted for potential lunar surface mission scenarios within NASA's Constellation Program. The scenarios investigated are based largely on results of the NASA Lunar Architecture Team (LAT) Phase II study. In particular, the possibility of "Hosted Sortie" missions, the high cost of power during eclipse periods, and the potential to reduce life support consumables through scavenging, in-situ resources, and alternative EVA technologies were all examined. These trade studies were performed within the Systems Integration, Modeling and Analysis (SIMA) element of NASA's Exploration Life Support (ELS) technology development project. The tools and methodology used in the study are described briefly, followed by a discussion of mission scenarios, life support technology options and results presented in terms of "equivalent system mass" for various regenerative life support technologies and architectures. Three classes of repeated or extended lunar surface missions were investigated in this study along with several life support resource scenarios for each mission class. Individual mission durations of 14 days, 90 days and 180 days were considered with 10 missions assumed for each at a rate of 2 missions per year. The 14-day missions represent a class of "Hosted Sortie" missions where a pre-deployed and potentially mobile habitat provides life support for multiple crews at one or more locations. The 90-day and 180-day missions represent lunar outpost expeditions with a larger fixed habitat. The 180-day missions assume continuous human presence and must provide life support through eclipse periods of up to 122 hours while the 90-day missions are planned for best-case periods of nearly continuous sunlight. This paper investigates system optimization within the assumptions of each scenario and addresses how the scenario selected drives the life support system to different designs

  20. Lunar Outpost Life Support Trade Studies

    NASA Technical Reports Server (NTRS)

    Lange, Kevin E.; Anderson, Molly S.; Ewert, Michael K.; Barta, Daniel J.

    2008-01-01

    Engineering trade-off studies of life support system architecture and technology options were conducted for potential lunar surface mission scenarios within NASA's Constellation Program. The scenarios investigated are based largely on results of the NASA Lunar Architecture Team (LAT) Phase II study. In particular, the possibility of Hosted Sortie missions, the high cost of power during eclipse periods, and the potential to reduce life support consumables through scavenging, in-situ resources, and alternative EVA technologies were all examined. These trade studies were performed within the Systems Integration, Modeling and Analysis (SIMA) element of NASA's Exploration Life Support (ELS) technology development project. The tools and methodology used in the study are described briefly, followed by a discussion of mission scenarios, life support technology options and results presented in terms of equivalent system mass for various regenerative life support technologies and architectures. Three classes of repeated or extended lunar surface missions were investigated in this study along with several life support resource scenarios for each mission class. Individual mission durations of 14 days, 90 days and 180 days were considered with 10 missions assumed for each at a rate of 2 missions per year. The 14-day missions represent a class of Hosted Sortie missions where a pre-deployed and potentially mobile habitat provides life support for multiple crews at one or more locations. The 90-day and 180-day missions represent lunar outpost expeditions with a larger fixed habitat. The 180-day missions assume continuous human presence and must provide life support through eclipse periods of up to 122 hours while the 90-day missions are planned for best-case periods of nearly continuous sunlight. This paper investigates system optimization within the assumptions of each scenario and addresses how the scenario selected drives the life support system to different designs

  1. British Support for English Studies in Europe.

    ERIC Educational Resources Information Center

    British Council, London (England). English-Teaching Information Centre.

    This survey attempts to document British support for English Studies in Europe. "English Studies" is interpreted as covering English language, British literature in English, and appropriate background studies. The first part consists of short descriptions of the activities of the principal organizations active in this field: Association of…

  2. Hwange power plant stage 3 expansion: Feasibility study update. Executive summary. Export trade information

    SciTech Connect

    1996-02-29

    The study, conducted by Black and Veatch International, was funded by the U.S. Trade and Development Agency. The report presents the study objectives and approach for the expansion of the Hwange Coal Fired Thermal Power Station- stage III. The objectives of the study include the identification of the least-cost-option, to determine the suitable conceptual design, and to review project implementation and financing. The report is divided into the following sections: (1) Introduction; (2) Objective and Approach; (3) Study Basis and Assumptions; (4) Sumamry of Conclusions and Recommendations; (5) Project Implementation.

  3. Experimental study of flow reattachment in a single-sided sudden expansion

    NASA Technical Reports Server (NTRS)

    Westphal, R. V.; Johnston, J. P.; Eaton, J. K.

    1984-01-01

    The reattachment of a fully turbulent, two dimensional, separated shear layer downstream of a single-sided sudden expansion in a planar duct flow was examined experimentally. The importance of changing the structure of the separated shear layer on the reattachment process itself was examined. For all cases, the Reynolds number based on step height was greater than 20,000, the expansion ratio was 5/3, and the inlet boundary layer was less than one-half step height in thickness. A crucially important phase was the development of a pulsed wall probe for measurement of skin friction in the reattachment region, thus providing an unambiguous definition of the reattachment length. Quantitative features of reattachment - including streamwise development of the mean and fluctuating velocity field, pressure rise, and skin friction - were found to be similar for all cases studied when scaled by the reattachment length. A definition of the reattachment zone is proposed.

  4. Magnetic phase transitions in heavy-fermion compounds studied by thermal-expansion measurements

    NASA Astrophysics Data System (ADS)

    de Visser, A.; Lacerda, A.; Franse, J. J. M.; Flouquet, J.

    1990-12-01

    On alloying the heavy-fermion compounds CeRu 2Si 2 and UPt 3 with small amounts of La and Pd, respectively, long-range antiferromagnetic order develops with Néel temperatures in the order of a few kelvin. In order to study the volume effects that are involved with the evolution into the long-range ordered state, we have performed thermal-expansion measurements on the pure and doped systems. The results are compared with data on antiferromagnetic URu 2Si 2. Subsequently, we discuss thermal-expansion measurements in high-magnetic fields, in particular on CeRu 2Si 2, where a metamagnetic-like transition occurs as the intersite-correlations collapse in a field of 7.8 T. Most of the measurements have been performed on single-crystalline samples, revealing a pronounced anisotropy.

  5. In vitro generated Th17 cells support the expansion and phenotypic stability of CD4(+)Foxp3(+) regulatory T cells in vivo.

    PubMed

    Zhou, Qiong; Hu, Ya; Howard, O M Zack; Oppenheim, Joost J; Chen, Xin

    2014-01-01

    CD4(+) T cells stimulate immune responses through distinct patterns of cytokine produced by Th1, Th2 or Th17 cells, or inhibit immune responses through Foxp3-expressing regulatory T cells (Tregs). Paradoxically, effector T cells were recently shown to activate Tregs, however, it remains unclear which Th subset is responsible for this effect. In this study, we found that Th17 cells expressed the highest levels of TNF among in vitro generated Th subsets, and most potently promoted expansion and stabilized Foxp3 expression by Tregs when co-transferred into Rag1(-/-) mice. Both TNF and IL-2 produced by Th17 cells contributed to this effect. The stimulatory effect of Th17 cells on Tregs was largely abolished when co-transferred with TNFR2-deficient Tregs. Furthermore, Tregs deficient in TNFR2 also supported a much lower production of IL-17A and TNF expression by co-transferred Th17 cells. Thus, our data indicate that the TNF-TNFR2 pathway plays a crucial role in the reciprocal stimulatory effect of Th17 cells and Tregs. This bidirectional interaction should be taken into account when designing therapy targeting Th17 cells, Tregs, TNF and TNFR2. PMID:24080164

  6. First-principles study on negative thermal expansion of PbTiO3

    NASA Astrophysics Data System (ADS)

    Wang, Fangfang; Xie, Ying; Chen, Jun; Fu, Honggang; Xing, Xianran

    2013-11-01

    It is well known that perovskite-type PbTiO3 behaves negative thermal expansion in a wide temperature range from room temperature to Curie temperature (763 K). The present study reports the first-principles study of the anisotropic thermal expansion of PbTiO3, in the framework of the density-functional theory and the density-functional perturbation theory. The curve of temperature dependence of the unit cell volume is presented from 20 to 520 K through the calculation of the minimum of total free energy at each temperature point. The negative thermal expansion of PbTiO3 is calculated without empirical parameters. Furthermore, the distinctive thermodynamic act of PbTiO3 from expanding to contracting at tetragonal phase is reproduced. The ab-initio calculations reveal that this unique appearance depends on the phonon vibration. The dynamical contributions of various atoms are also calculated to account for the disparate role of Pb-O and Ti-O bond.

  7. First-principles study on negative thermal expansion of PbTiO{sub 3}

    SciTech Connect

    Wang, Fangfang; Chen, Jun; Xing, Xianran; Xie, Ying; Fu, Honggang

    2013-11-25

    It is well known that perovskite-type PbTiO{sub 3} behaves negative thermal expansion in a wide temperature range from room temperature to Curie temperature (763 K). The present study reports the first-principles study of the anisotropic thermal expansion of PbTiO{sub 3}, in the framework of the density-functional theory and the density-functional perturbation theory. The curve of temperature dependence of the unit cell volume is presented from 20 to 520 K through the calculation of the minimum of total free energy at each temperature point. The negative thermal expansion of PbTiO{sub 3} is calculated without empirical parameters. Furthermore, the distinctive thermodynamic act of PbTiO{sub 3} from expanding to contracting at tetragonal phase is reproduced. The ab-initio calculations reveal that this unique appearance depends on the phonon vibration. The dynamical contributions of various atoms are also calculated to account for the disparate role of Pb-O and Ti-O bond.

  8. Ground-based studies of ionospheric convection associated with substorm expansion

    NASA Technical Reports Server (NTRS)

    Kamide, Y.; Richmond, A. D.; Emery, B. A.; Hutchins, C. F.; Ahn, B.-H.; De La Beaujardiere, O.; Foster, J. C.; Heelis, R. A.; Kroehl, H. W.; Rich, F. J.

    1994-01-01

    The instantaneous patterns of electric fields and currents in the high-latitude ionosphere are deduced by combining satellite and radar measurements of the ionospheric drift velocity, along with ground-based magnetometer observations for October 25, 1981. The period under study was characterized by a relatively stable southward interplanetary magnetic field (IMF), so that the obtained electric field patterns do reflect, in general, the state of sustained and enhanced plasma convection in the magnetosphere. During one of the satellite passes, however, an intense westward electrojet caused by a substorm intruded into the satellite (DE2) and radar (Chatanika, Alaska) field of view in the premidnight sector, providing a unique opportunity to differentiate the enhanced convection and substorm expansion fields. The distributions of the calculated electric potential for the expansion and maximum phases of the substorm show the first clear evidence of the coexistence of two physically different systems in the global convection pattern. The changes in the convection pattern during the substorm indicate that the large-scale potential distributions are indeed of general two-cell patterns representing the southward IMF status, but the night-morning cell has two positive peaks, one in the midnight sector and the other in the late morning hours, corresponding to the substorm expansion and the convection enhancement, respectively.

  9. A study of the bending motion in tetratomic molecules by the algebraic operator expansion method.

    PubMed

    Larese, Danielle; Caprio, Mark A; Pérez-Bernal, Francisco; Iachello, Francesco

    2014-01-01

    We study the bending motion in the tetratomic molecules C2H2 (X̃ (1)Σg (+)), C2H2 (Ã (1)Au) trans-S1, C2H2 (Ã (1)A2) cis-S1, and X̃ (1)A1 H2CO. We show that the algebraic operator expansion method with only linear terms comprised of the basic operators is able to describe the main features of the level energies in these molecules in terms of two (linear) or three (trans-bent, cis-bent, and branched) parameters. By including quadratic terms, the rms deviation in comparison with experiment goes down to typically ∼10 cm(-1) over the entire range of energy 0-6000 cm(-1). We determine the parameters by fitting the available data, and from these parameters we construct the algebraic potential functions. Our results are of particular interest in high-energy regions where spectra are very congested and conventional methods, force-field expansions or Dunham-expansions plus perturbations, are difficult to apply. PMID:24410226

  10. Ground-based studies of ionospheric convection associated with substorm expansion

    SciTech Connect

    Kamide, Y. |; Richmond, A.D.; Emery, B.A.; Hutchins, C.F.; Ahn, B.H. |; Beaujardiere, O. de la; Foster, J.C.; Heelis, R.A.; Kroehl, H.W.; Rich, F.J.

    1994-10-01

    The instantaneous patterns of electric fields and currents in the high-latitude ionosphere are deduced by combining satellite and radar measurements of the ionospheric drift velocity, along with ground-based magnetometer observations for October 25, 1981. For this purpose, an updated version of the assimilative mapping of ionospheric electrodynamics technique has been used. These global patterns are unobtainable from any single data set. The period under study was characterized by a relatively stable southward interplanetary magnetic field (IMF), so that the obtained electric field patterns do reflect, in general, the state of sustained and enhanced plasma convection in the magnetosphere. During one of the satellite passes, however, an intense westward electrojet caused by a substorm intruded into the satellite (DE 2) and radar (Chatanika, Alaska) field of view in the premidnight sector, providing a unique opportunity to differentiate the enhanced convection and substorm expansion fields. The distributions of the calculated electric potential for the expansion and maximum phases of the substorm show the first clear evidence of the coexistence of two physically different systems in the global convection pattern. The changes in the convection pattern during the substorm indicate that the large-scale potential distributions are indeed of general two-cell patterns representing the southward IMF status, but the night-morning cell has two positive peaks, one in the midnight sector and the other in the late morning hours, corresponding to the substorm expansion and the convection enhancement, respectively. 40 refs., 12 figs., 1 tab.

  11. Molecular determinants of expansivity of native globular proteins: a pressure perturbation calorimetry study.

    PubMed

    Vasilchuk, Daniel; Pandharipande, Pranav P; Suladze, Saba; Sanchez-Ruiz, Jose M; Makhatadze, George I

    2014-06-12

    There is a growing interest in understanding how hydrostatic pressure (P) impacts the thermodynamic stability (ΔG) of globular proteins. The pressure dependence of stability is defined by the change in volume upon denaturation, ΔV = (∂ΔG/∂P)T. The temperature dependence of change in volume upon denaturation itself is defined by the changes in thermal expansivity (ΔE), ΔE = (∂ΔV/∂T)P. The pressure perturbation calorimetry (PPC) allows direct experimental measurement of the thermal expansion coefficient, α = E/V, of a protein in the native, αN(T), and unfolded, αU(T), states as a function of temperature. We have shown previously that αU(T) is a nonlinear function of temperature but can be predicted well from the amino acid sequence using α(T) values for individual amino acids (J. Phys. Chem. B 2010, 114, 16166-16170). In this work, we report PPC results on a diverse set of nine proteins and discuss molecular factors that can potentially influence the thermal expansion coefficient, αN(T), and the thermal expansivity, EN(T), of proteins in the native state. Direct experimental measurements by PPC show that αN(T) and EN(T) functions vary significantly for different proteins. Using comparative analysis and site-directed mutagenesis, we have eliminated the role of various structural or thermodynamic properties of these proteins such as the number of amino acid residues, secondary structure content, packing density, electrostriction, dynamics, or thermostability. We have also shown that αN(T) and EN,sp(T) functions for a given protein are rather insensitive to the small changes in the amino acid sequence, suggesting that αN(T) and EN(T) functions might be defined by a topology of a given protein fold. This conclusion is supported by the similarity of αN(T) and EN(T) functions for six resurrected ancestral thioredoxins that vary in sequence but have very similar tertiary structure. PMID:24849138

  12. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry

    SciTech Connect

    Zheng, Fasong; Tan, Yidong; Zhang, Shulian; Lin, Jing; Ding, Yingchun

    2015-04-15

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10{sup −6}(K{sup −1}) at the range of 298 K–598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K–748 K.

  13. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry

    NASA Astrophysics Data System (ADS)

    Zheng, Fasong; Tan, Yidong; Lin, Jing; Ding, Yingchun; Zhang, Shulian

    2015-04-01

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10-6(K-1) at the range of 298 K-598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K-748 K.

  14. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry.

    PubMed

    Zheng, Fasong; Tan, Yidong; Lin, Jing; Ding, Yingchun; Zhang, Shulian

    2015-04-01

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10(-6)(K(-1)) at the range of 298 K-598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K-748 K. PMID:25933843

  15. Ab initio lattice dynamical studies of silicon clathrate frameworks and their negative thermal expansion

    NASA Astrophysics Data System (ADS)

    Härkönen, Ville J.; Karttunen, Antti J.

    2014-01-01

    The thermal and lattice dynamical properties of seven silicon clathrate framework structures are investigated with ab initio density functional methods (frameworks I, II, IV, V, VII, VIII, and H). The negative thermal expansion (NTE) phenomenon is investigated by means of quasiharmonic approximation and applying it to equal time displacement correlation functions. The thermal properties of the studied clathrate frameworks, excluding the VII framework, resemble those of the crystalline silicon diamond structure. The clathrate framework VII was found to have an anomalous NTE temperature range up to 300 K and it is suitable for further studies of the mechanisms of NTE. Investigation of the displacement correlation functions revealed that in NTE, the volume derivatives of the mean square displacements and mean square relative displacements of atoms behave similarly to the vibrational entropy volume derivatives and consequently to the coefficients of thermal expansion as a function of temperature. All studied clathrate frameworks, excluding the VII framework, possess a phonon band gap or even two in the case of framework V.

  16. Human CD34(lo)CD133(lo) fetal liver cells support the expansion of human CD34(hi)CD133(hi) hematopoietic stem cells.

    PubMed

    Yong, Kylie Su Mei; Keng, Choong Tat; Tan, Shu Qi; Loh, Eva; Chang, Kenneth Te; Tan, Thiam Chye; Hong, Wanjin; Chen, Qingfeng

    2016-09-01

    We have recently discovered a unique CD34(lo)CD133(lo) cell population in the human fetal liver (FL) that gives rise to cells in the hepatic lineage. In this study, we further characterized the biological functions of FL CD34(lo)CD133(lo) cells. Our findings show that these CD34(lo)CD133(lo) cells express markers of both endodermal and mesodermal lineages and have the capability to differentiate into hepatocyte and mesenchymal lineage cells by ex vivo differentiation assays. Furthermore, we show that CD34(lo)CD133(lo) cells express growth factors that are important for human hematopoietic stem cell (HSC) expansion: stem cell factor (SCF), insulin-like growth factor 2 (IGF2), C-X-C motif chemokine 12 (CXCL12), and factors in the angiopoietin-like protein family. Co-culture of autologous FL HSCs and allogenic HSCs derived from cord blood with CD34(lo)CD133(lo) cells supports and expands both types of HSCs.These findings are not only essential for extending our understanding of the HSC niche during the development of embryonic and fetal hematopoiesis but will also potentially benefit adult stem cell transplantations in clinics because expanded HSCs demonstrate the same capacity as primary cells to reconstitute the human immune system and mediate long-term hematopoiesis in vivo. Together, CD34(lo)CD133(lo) cells not only serve as stem/progenitor cells for liver development but are also an essential component of the HSC niche in the human FL. PMID:27593483

  17. A STUDY ON DEF-RELATED EXPANSION IN HEAT-CURED CONCRETE

    NASA Astrophysics Data System (ADS)

    Kawabata, Yuichiro; Matsushita, Hiromichi

    This paper reports the requirements for deleterious expansion due to delayed ettringite formation (DEF) based on field experience. In recent years, the delete rious expansion of concrete have been reported. The concrete have been characterized by expansion and cracking after several years of service in environments exposed in wet conditions. In many cases, the concrete consists of white cement, limestone and copper slag and it has been manufactured at elevated temperatures for early shipment. From detailed analysis, it was made clear that the cause of deleterious expansion was DEF. The gaps which are featured in DEF-damaged concrete were observed around limest one aggregate. There was a possibility that use of limestone aggregate affects DEF-related expansion while the condition of steam curing was the most effective factor for DEF-related expansion. Based on experimental data, the mechanism of DEF-related expansion and the methodology of diagnosing DEF-deterior ated concrete structures were discussed in this paper.

  18. Experimental study of rotating Hagen-Poiseuille flow discharging into a 1:8 sudden expansion

    NASA Astrophysics Data System (ADS)

    Miranda-Barea, A.; Martínez-Arias, B.; Parras, L.; Burgos, M. A.; del Pino, C.

    2015-03-01

    In this paper, we present experimental evidence for the five different states that result from rotating Hagen-Poiseuille flow when it discharges into a 1:8 sudden expansion, namely: stable, convectively unstable, unstable shear layer, stable and unstable vortex breakdowns. Sanmiguel-Rojas et al. ["Three-dimensional structure of confined swirling jets at moderately large Reynolds numbers," Phys. Fluids 20, 044104 (2008)] numerically predicted four of these five states and mapped the transition from one state to another. Our main objective is to study the onset of instabilities and vortex breakdown in these states experimentally. For this purpose, we visualize the flow at the inlet of the expansion for several values of moderately large Reynolds numbers, Re, and of swirl parameters, S. We analyze the inner region of the state that corresponds to the unstable shear layer in the sudden expansion and find two different states that share the same character, although they have different non-dimensional frequencies. The first relates to an oscillating structure near the axis, which arises at a small value of the swirl parameter, as well as to a generation of vortices that move downstream. The second shows, for greater values of the swirl parameter, vortices interacting with the boundary layer located on the wall of the static container that is perpendicular to the flow direction. In addition, we find a transition from stable to unstable vortex breakdown when perturbations become absolutely unstable inside the rotating pipe flow. Therefore, the most remarkable experimental finding is a new state, namely, unstable or transient vortex breakdown that takes place for the same pair of values (Rea, Sa) at which the onset of the absolute instability curve appears and intersects the region of stable vortex breakdown.

  19. Genetic code expansion as a tool to study regulatory processes of transcription

    PubMed Central

    Schmidt, Moritz J.; Summerer, Daniel

    2014-01-01

    The expansion of the genetic code with non-canonical amino acids (ncAA) enables the chemical and biophysical properties of proteins to be tailored, inside cells, with a previously unattainable level of precision. A wide range of ncAA with functions not found in canonical amino acids have been genetically encoded in recent years and have delivered insights into biological processes that would be difficult to access with traditional approaches of molecular biology. A major field for the development and application of novel ncAA-functions has been transcription and its regulation. This is particularly attractive, since advanced DNA sequencing- and proteomics-techniques continue to deliver vast information on these processes on a global level, but complementing methodologies to study them on a detailed, molecular level and in living cells have been comparably scarce. In a growing number of studies, genetic code expansion has now been applied to precisely control the chemical properties of transcription factors, RNA polymerases and histones, and this has enabled new insights into their interactions, conformational changes, cellular localizations and the functional roles of posttranslational modifications. PMID:24790976

  20. Genetic Code Expansion as a Tool to Study Regulatory Processes of Transcription

    NASA Astrophysics Data System (ADS)

    Schmidt, Moritz; Summerer, Daniel

    2014-02-01

    The expansion of the genetic code with noncanonical amino acids (ncAA) enables the chemical and biophysical properties of proteins to be tailored, inside cells, with a previously unattainable level of precision. A wide range of ncAA with functions not found in canonical amino acids have been genetically encoded in recent years and have delivered insights into biological processes that would be difficult to access with traditional approaches of molecular biology. A major field for the development and application of novel ncAA-functions has been transcription and its regulation. This is particularly attractive, since advanced DNA sequencing- and proteomics-techniques continue to deliver vast information on these processes on a global level, but complementing methodologies to study them on a detailed, molecular level and in living cells have been comparably scarce. In a growing number of studies, genetic code expansion has now been applied to precisely control the chemical properties of transcription factors, RNA polymerases and histones, and this has enabled new insights into their interactions, conformational changes, cellular localizations and the functional roles of posttranslational modifications.

  1. Parametric study of a simultaneous pitch/yaw thrust vectoring single expansion ramp nozzle

    NASA Technical Reports Server (NTRS)

    Schirmer, Alberto W.; Capone, Francis J.

    1989-01-01

    In the course of the last eleven years, the concept of thrust vectoring has emerged as a promising method of enhancing aircraft control capabilities in post-stall flight incursions during combat. In order to study the application of simultaneous pitch and yaw vectoring to single expansion ramp nozzles, a static test was conducted in the NASA-Langley 16 foot transonic tunnel. This investigation was based on internal performance data provided by force, mass flow and internal pressure measurements at nozzle pressure ratios up to 8. The internal performance characteristics of the nozzle were studied for several combinations of six different parameters: yaw vectoring angle, pitch vectoring angle, upper ramp cutout, sidewall hinge location, hinge inclination angle and sidewall containment. Results indicated a 2-to- 3-percent decrease in resultant thrust ratio with vectoring in either pitch or yaw. Losses were mostly associated with the turning of supersonic flow. Resultant thrust ratios were also decreased by sideways expansion of the jet. The effects of cutback corners in the upper ramp and lower flap on performance were small. Maximum resultant yaw vector angles, about half of the flap angle, were achieved for the configuration with the most forward hinge location.

  2. A Study of Free-Piston Double-Diaphragm Drivers for Expansion Tubes. Report 1

    NASA Technical Reports Server (NTRS)

    Kendall, M. A.

    1997-01-01

    In recent years the free-piston double-diaphragm driver has been used to increase the performance of the XI pilot expansion tube to super-orbital test conditions. However, the actual performance of the double-diaphragm driver was found to be considerably less than ideal. An experimental study of the double-diaphragm driver was carried out on the XI facility over a range of conditions with the objective of determining the effect of. heat losses; and the non-ideal rupture of the 'light' secondary diaphragm on the driver performance. The disparity between the theoretical and measured performance envelope are highlighted. A viscous limit for the experiments vas established. Heat transfer behind the primary shock is shown to be the mechanism behind this limit Incident, reflected and transmitted shock trajectories for the secondary diaphragm were experimentally determined and compared with computed trajectories from a one-dimensional diaphragm inertia model. It was found that the diaphragm did influence the unsteady expansion. A good agreement between experimental and computed shock trajectories was obtained using a diaphragm inertia model assuming that the diaphragm mass became negligible 3 microns after shock impact.

  3. Growth Type and Functional Trajectories: An Empirical Study of Urban Expansion in Nanjing, China.

    PubMed

    Chen, Jianglong; Gao, Jinlong; Yuan, Feng

    2016-01-01

    Drawing upon the Landsat satellite images of Nanjing from 1985, 1995, 2001, 2007, and 2013, this paper integrates the convex hull analysis and common edge analysis at double scales, and develops a comprehensive matrix analysis to distinguish the different types of urban land expansion. The results show that Nanjing experienced rapid urban expansion, dominated by a mix of residential and manufacturing land from 1985 to 2013, which in turn has promoted Nanjing's shift from a compact mononuclear city to a polycentric one. Spatial patterns of three specific types of growth, namely infilling, extension, and enclave were quite different in four consecutive periods. These patterns result primarily from the existing topographic constraints, as well as government-oriented urban planning and policies. By intersecting the function maps, we also reveal the functional evolution of newly-developed urban land. Moreover, both self-enhancing and mutual promotion of the newly developed functions are surveyed over the last decade. Our study confirms that the integration of a multi-scale method and multi-perspective analysis, such as the spatiotemporal patterns and functional evolution, helps us to better understand the rapid urban growth in China. PMID:26845155

  4. Growth Type and Functional Trajectories: An Empirical Study of Urban Expansion in Nanjing, China

    PubMed Central

    Yuan, Feng

    2016-01-01

    Drawing upon the Landsat satellite images of Nanjing from 1985, 1995, 2001, 2007, and 2013, this paper integrates the convex hull analysis and common edge analysis at double scales, and develops a comprehensive matrix analysis to distinguish the different types of urban land expansion. The results show that Nanjing experienced rapid urban expansion, dominated by a mix of residential and manufacturing land from 1985 to 2013, which in turn has promoted Nanjing’s shift from a compact mononuclear city to a polycentric one. Spatial patterns of three specific types of growth, namely infilling, extension, and enclave were quite different in four consecutive periods. These patterns result primarily from the existing topographic constraints, as well as government-oriented urban planning and policies. By intersecting the function maps, we also reveal the functional evolution of newly-developed urban land. Moreover, both self-enhancing and mutual promotion of the newly developed functions are surveyed over the last decade. Our study confirms that the integration of a multi-scale method and multi-perspective analysis, such as the spatiotemporal patterns and functional evolution, helps us to better understand the rapid urban growth in China. PMID:26845155

  5. A study of single and binary ion plasma expansion into laboratory-generated plasma wakes

    NASA Technical Reports Server (NTRS)

    Wright, Kenneth Herbert, Jr.

    1988-01-01

    Plasma expansion into the wake of a large rectangular plate immersed in a collisionless, supersonic plasma was investigated in laboratory experiments. The experimental conditions address both single ion and binary ion plasma flows for the case of a body whose size is large in comparison with the Debye length, when the potential difference between the body and the plasma is relatively small. A new plasma source was developed to generate equi-velocity, binary ion plasma flows, which allows access to new parameter space that have previously been unavailable for laboratory studies. Specifically, the new parameters are the ionic mass ratio and the ionic component density ratio. In a series of experiments, a krypton-neon plasma is employed where the ambient density ratio of neon to krypton is varied more than an order of magnitude. The expansion in both the single ion and binary ion plasma cases is limited to early times, i.e., a few ion plasma periods, by the combination of plasma density, plasma drift speed, and vacuum chamber size, which prevented detailed comparison with self-similar theory.

  6. Plume expansion of a laser-induced plasma studied with the particle-in-cell method

    NASA Astrophysics Data System (ADS)

    Ellegaard, O.; Nedelea, T.; Schou, J.; Urbassek, H. M.

    2002-09-01

    The initial stage of laser-induced plasma plume expansion from a solid in vacuum and the effect of the Coulomb field have been studied. We have performed a one-dimensional numerical calculation by mapping the charge on a computational grid according to the particle-in-cell (PIC) method of Birdsall et al. It is assumed that the particle ablation from a surface with a fixed temperature takes place as a pulse, i.e. within a finite period of time. A number of characteristic quantities for the plasma plume are compared with similar data for expansion of neutrals as well as fluid models: Density profiles n( x, t), velocity distributions of ions u( x, t), distribution functions for velocities F( vx) of ions or electrons as well as the time dependence of kinetic energy Ekin( t) for both type of particles. We found a significant increase in the velocities of the ions at the expense of field potential energy as well as electron energy. We have estimated the time constant for energy transfer between the electrons and the ions. The scaling of these processes is given by a single parameter determined by the Debye length obtained from the electron density in the plasma outside the surface.

  7. Ground-based studies of ionospheric convection associated with substorm expansion

    SciTech Connect

    Kamide, Y.; Richmond, A.D.; Emery, B.A.; Hutchins, C.F.; Ahn, B.H.

    1994-10-01

    The instantaneous patterns of electric fields and currents in the high-latitude ionosphere are deduced by combining satellite and radar measurements of the ionospheric drift velocity, along with ground-based magnetometer observations for October 25, 1981. For this purpose, an updated version of the assimilative mapping of ionospheric electrodynamics technique has been used. These global patterns are unobtainable from any single data set. The period under study was characterized by a relatively stable southward interplanetary magnetic field (IMF), so that the obtained electric field patterns do reflect, in genernal, the state of sustained and enhanced plasma convection in the magnetosphere. During one of the satellite passes, however, an intense westward electrojet caused by a substorm intruded into the satellite (DE 2) and radar (Chatanika, Alaska) field of view in the premidnight sector, providing a unique opportunity to differentiate the enhanced convection and substorm expansion fields. The distributions of the calculated electric potential for the epansion and maximum phases of the substorm show the first clear evidence of the coezistence of two physically different systems in the global convection pattern. The changes in the convection pattern during the substorm indicate that the large-scale potential distributions are indeed of general two-cell patterns representing the southward LMF status, but the night-morning cell has two positive peaks, one in the midnight sector and the other in the late morning hours, corresponding to the substorm expansion and the convection enhancement respectively.

  8. A study of plasma expansion phenomena in laboratory generated plasma wakes - Preliminary results

    NASA Technical Reports Server (NTRS)

    Wright, K. H., Jr.; Stone, N. H.; Samir, U.

    1985-01-01

    The plasma expansion into the wake of a large rectangular plate immersed in a single-ion, collisionless, streaming plasma has been investigated in the laboratory. Several characteristics of the process involved in 'plasma expansion into vacuum' that have been predicted theoretically were observed, including the creation and motion of a rarefaction wave disturbance; the creation and motion of an expansion front; and the acceleration of ions into the wake at speeds above the ion-acoustic speed. The expansion was limited to early times; i.e., a few ion plasma periods, by the combination of plasma drift speed and vacuum chamber size. This prevented detailed comparison with self-similar theory, but results are in good agreement with numerical simulations and other laboratory experiments for the early time expansion. The conclusion is that the plasma expansion process is the dominant wake filling mechanism in the near wake of a body, whose potential is approximately the plasma space potential.

  9. A Robust Single Primate Neuroepithelial Cell Clonal Expansion System for Neural Tube Development and Disease Studies

    PubMed Central

    Zhu, Xiaoqing; Li, Bo; Ai, Zongyong; Xiang, Zheng; Zhang, Kunshang; Qiu, Xiaoyan; Chen, Yongchang; Li, Yuemin; Rizak, Joshua D.; Niu, Yuyu; Hu, Xintian; Sun, Yi Eve; Ji, Weizhi; Li, Tianqing

    2015-01-01

    Summary Developing a model of primate neural tube (NT) development is important to promote many NT disorder studies in model organisms. Here, we report a robust and stable system to allow for clonal expansion of single monkey neuroepithelial stem cells (NESCs) to develop into miniature NT-like structures. Single NESCs can produce functional neurons in vitro, survive, and extensively regenerate neuron axons in monkey brain. NT formation and NESC maintenance depend on high metabolism activity and Wnt signaling. NESCs are regionally restricted to a telencephalic fate. Moreover, single NESCs can turn into radial glial progenitors (RGPCs). The transition is accurately regulated by Wnt signaling through regulation of Notch signaling and adhesion molecules. Finally, using the “NESC-TO-NTs” system, we model the functions of folic acid (FA) on NT closure and demonstrate that FA can regulate multiple mechanisms to prevent NT defects. Our system is ideal for studying NT development and diseases. PMID:26584544

  10. A Robust Single Primate Neuroepithelial Cell Clonal Expansion System for Neural Tube Development and Disease Studies.

    PubMed

    Zhu, Xiaoqing; Li, Bo; Ai, Zongyong; Xiang, Zheng; Zhang, Kunshang; Qiu, Xiaoyan; Chen, Yongchang; Li, Yuemin; Rizak, Joshua D; Niu, Yuyu; Hu, Xintian; Sun, Yi Eve; Ji, Weizhi; Li, Tianqing

    2016-02-01

    Developing a model of primate neural tube (NT) development is important to promote many NT disorder studies in model organisms. Here, we report a robust and stable system to allow for clonal expansion of single monkey neuroepithelial stem cells (NESCs) to develop into miniature NT-like structures. Single NESCs can produce functional neurons in vitro, survive, and extensively regenerate neuron axons in monkey brain. NT formation and NESC maintenance depend on high metabolism activity and Wnt signaling. NESCs are regionally restricted to a telencephalic fate. Moreover, single NESCs can turn into radial glial progenitors (RGPCs). The transition is accurately regulated by Wnt signaling through regulation of Notch signaling and adhesion molecules. Finally, using the "NESC-TO-NTs" system, we model the functions of folic acid (FA) on NT closure and demonstrate that FA can regulate multiple mechanisms to prevent NT defects. Our system is ideal for studying NT development and diseases. PMID:26584544

  11. Numerical Study of Interaction of a Vortical Density Inhomogeneity with Shock and Expansion Waves

    NASA Technical Reports Server (NTRS)

    Povitsky, A.; Ofengeim, D.

    1998-01-01

    We studied the interaction of a vortical density inhomogeneity (VDI) with shock and expansion waves. We call the VDI the region of concentrated vorticity (vortex) with a density different from that of ambiance. Non-parallel directions of the density gradient normal to the VDI surface and the pressure gradient across a shock wave results in an additional vorticity. The roll-up of the initial round VDI towards a non-symmetrical shape is studied numerically. Numerical modeling of this interaction is performed by a 2-D Euler code. The use of an adaptive unstructured numerical grid makes it possible to obtain high accuracy and capture regions of induced vorticity with a moderate overall number of mesh points. For the validation of the code, the computational results are compared with available experimental results and good agreement is obtained. The interaction of the VDI with a propagating shock wave is studied for a range of initial and induced circulations and obtained flow patterns are presented. The splitting of the VDI develops into the formation of a non-symmetrical vortex pair and not in a set of vortices. A method for the analytical computation of an overall induced circulation Gamma(sub 1) as a result of the interaction of a moving VDI with a number of waves is proposed. Simplified, approximated, expressions for Gamma(sub 1) are derived and their accuracy is discussed. The splitting of the VDI passing through the Prandtl-Meyer expansion wave is studied numerically. The obtained VDI patterns are compared to those for the interaction of the VDI with a propagating shock wave for the same values of initial and induced circulations. These patterns have similar shapes for corresponding time moments.

  12. Anisotropic thermal expansion in Sr2RhO4 - A variable temperature Synchrotron X-ray diffraction study

    NASA Astrophysics Data System (ADS)

    Ranjbar, Ben; Kennedy, Brendan J.

    2015-11-01

    Synchrotron X-ray diffraction studies of Sr2RhO4, between 100 and 1273 K, demonstrate the presence of anisotropic thermal expansion that is significantly impacted by the progressive reduction in the size of the cooperative tilting of the corner sharing RhO6 octahedra. The tilting results in negative thermal expansion along the c-axis, demonstrating the importance of soft phonon modes. This anisotropy in thermal expansion is reflected in the changes in the individual Rh-O bond distances. Near 850 K Sr2RhO4 undergoes an apparently continuous transition from I41/acd to I4/mmm and above this temperature the material displays typical positive thermal expansion.

  13. The Study on Thermal Expansion of Ceramic Composites with Addition of ZrW2O8

    NASA Astrophysics Data System (ADS)

    Dedova, E. S.; Shadrin, V. S.; Petrushina, M. Y.; Kulkov, S. N.

    2016-02-01

    The studies on structure, phase composition and thermal properties of (Al2O3 - 20 wt% ZrO2) - ZrW2O8 ceramic composites obtained using nanosized, initial powders were conducted. Homogeneously distributed white particles on the polished surface of composites were observed. Phase composition of the composites was represented with corundum, monoclinic ZrO2 and two modifications of ZrW2O8 (tetragonal and cubic). Linear thermal expansion coefficient values of the composites were determined. The difference in experimental and calculated coefficient of thermal expansion values for composites obtained may be attributed to phase transformations, features of the structure, internal stresses due to thermal expansion mismatch, which contribute significantly to thermal expansion of the ceramic composites.

  14. A comparative study of plasma expansion events in the polar wind

    NASA Technical Reports Server (NTRS)

    Gombosi, Tamas I.; Schunk, Robert W.

    1988-01-01

    The temporal characteristics of the polar wind have been studied using a simplified set of collisionless equations and a full set of hydrodynamic equations which contained continuity, momentum, and energy equations for H(+), O(+), and electrons, including collisional conductivities and variable isotropic, ion and electron temperatures. The temporal evolution of the polar wind was modeled for initial, extended density depletions of factors of 3, 10, and 100 starting at several altitudes for each model. Comparison of the results from the two models showed the same temporal characteristics for the polar wind densities, flow velocities, and escape fluxes. The characteristics of plasma expansion are presented. It is found that the propagation velocities of the disturbance vary with the level of the depletion.

  15. First-principles cluster expansion study of functionalization of black phosphorene via fluorination and oxidation

    NASA Astrophysics Data System (ADS)

    Nahas, Suhas; Ghosh, Barun; Bhowmick, Somnath; Agarwal, Amit

    2016-04-01

    Predicting the ground states for surface adsorption is a challenging problem because the number of degrees of freedom involved in the process is very high. Most of the studies deal with some specific arrangements of adsorbates on a given surface, but very few of them actually attempt to find the ground states for different adatom coverage. In this work, we show the effectiveness of the cluster expansion method to predict the "ground states" resulting from chemisorption of oxygen and fluorine atom on the surface of monolayer black phosphorus or phosphorene. For device applications, we find that in addition to band-gap tuning, controlled chemisorption can change the unique anisotropic carrier effective mass for both the electrons and holes and even rotate them by 90∘, which can be useful for exploring unusual quantum Hall effect and electronic devices based on phosphorene.

  16. An analysis of combustion studies in shock expansion tunnels and reflected shock tunnels

    NASA Technical Reports Server (NTRS)

    Jachimowski, Casimir J.

    1992-01-01

    The effect of initial nonequilibrium dissociated air constituents on the combustion of hydrogen in high-speed flows for a simulated Mach 17 flight condition was investigated by analyzing the results of comparative combustion experiments performed in a reflected shock tunnel test gas and in a shock expansion tunnel test gas. The results were analyzed and interpreted with a one-dimensional quasi-three-stream combustor code that includes finite rate combustion chemistry. The results of this study indicate that the combustion process is kinetically controlled in the experiments in both tunnels and the presence of the nonequilibrium partially dissociated oxygen in the reflected shock tunnel enhances the combustion. Methods of compensating for the effect of dissociated oxygen are discussed.

  17. Assured Mission Support Space Architecture (AMSSA) study

    NASA Technical Reports Server (NTRS)

    Hamon, Rob

    1993-01-01

    The assured mission support space architecture (AMSSA) study was conducted with the overall goal of developing a long-term requirements-driven integrated space architecture to provide responsive and sustained space support to the combatant commands. Although derivation of an architecture was the focus of the study, there are three significant products from the effort. The first is a philosophy that defines the necessary attributes for the development and operation of space systems to ensure an integrated, interoperable architecture that, by design, provides a high degree of combat utility. The second is the architecture itself; based on an interoperable system-of-systems strategy, it reflects a long-range goal for space that will evolve as user requirements adapt to a changing world environment. The third product is the framework of a process that, when fully developed, will provide essential information to key decision makers for space systems acquisition in order to achieve the AMSSA goal. It is a categorical imperative that military space planners develop space systems that will act as true force multipliers. AMSSA provides the philosophy, process, and architecture that, when integrated with the DOD requirements and acquisition procedures, can yield an assured mission support capability from space to the combatant commanders. An important feature of the AMSSA initiative is the participation by every organization that has a role or interest in space systems development and operation. With continued community involvement, the concept of the AMSSA will become a reality. In summary, AMSSA offers a better way to think about space (philosophy) that can lead to the effective utilization of limited resources (process) with an infrastructure designed to meet the future space needs (architecture) of our combat forces.

  18. Study on a new type of jet pressurization evaporation expansion apparatus

    NASA Astrophysics Data System (ADS)

    Chen, Boyi; Zhang, Mingxin; Yang, Li

    2001-04-01

    The volume expansion of the stuff (e. g. tobacco stem) is of great importance to an increase in the product quality and a decrease in the production cost. This paper puts forward the basic configuration and the expansion mechanism of a new type of jet pressurization evaporation expansion apparatus. By the thermodynamic calculation of the apparatus, we give variations in steam pressure on various cross sections of the flow system for the apparatus, manufacture a sample machine, and finish run tests of the machine. The test results show that the apparatus may make the relative increase in fill value of tobacco stem higher than 75%, and may cause the steam consumption required in the expansion process of each kilogram stem to reduced about 40% compared with conventional expansion apparatus. Additionally, the configuration of the apparatus is simple and small, its cost of manufacture is very low, and both its operation and maintenance are extremely convenient.

  19. A simulation study of radial expansion of an electron beam injected into an ionospheric plasma

    NASA Technical Reports Server (NTRS)

    Koga, J.; Lin, C. S.

    1994-01-01

    Injections of nonrelativistic electron beams from a finite equipotential conductor into an ionospheric plasma have been simulated using a two-dimensional electrostatic particle code. The purpose of the study is to survey the simulation parameters for understanding the dependence of beam radius on physical variables. The conductor is charged to a high potential when the background plasma density is less than the beam density. Beam electrons attracted by the charged conductor are decelerated to zero velocity near the stagnation point, which is at a few Debye lengths from the conductor. The simulations suggest that the beam electrons at the stagnation point receive a large transverse kick and the beam expands radially thereafter. The buildup of beam electrons at the stagnation point produces a large electrostatic force responsible for the transverse kick. However, for the weak charging cases where the background plasma density is larger than the beam density, the radial expansion mechanism is different; the beam plasma instability is found to be responsible for the radial expansion. The simulations show that the electron beam radius for high spacecraft charging cases is of the order of the beam gyroradius, defined as the beam velocity divided by the gyrofrequency. In the weak charging cases, the beam radius is only a fraction of the beam gyroradius. The parameter survey indicates that the beam radius increases with beam density and decreases with magnetic field and beam velocity. The beam radius normalized by the beam gyroradius is found to scale according to the ratio of the beam electron Debye length to the ambient electron Debye length. The parameter dependence deduced would be useful for interpreting the beam radius and beam density of electron beam injection experiments conducted from rockets and the space shuttle.

  20. Applications of Floquet-Magnus expansion, average Hamiltonian theory and Fer expansion to study interactions in solid state NMR when irradiated with the magic-echo sequence.

    PubMed

    Mananga, Eugene Stephane

    2013-01-01

    This work presents the possibility of applying the Floquet-Magnus expansion and the Fer expansion approaches to the most useful interactions known in solid-state nuclear magnetic resonance using the magic-echo scheme. The results of the effective Hamiltonians of these theories and average Hamiltonian theory are presented. PMID:24034855

  1. New mitochondrial and nuclear evidences support recent demographic expansion and an atypical phylogeographic pattern in the spittlebug Philaenus spumarius (Hemiptera, Aphrophoridae).

    PubMed

    Rodrigues, Ana S B; Silva, Sara E; Marabuto, Eduardo; Silva, Diogo N; Wilson, Mike R; Thompson, Vinton; Yurtsever, Selçuk; Halkka, Antti; Borges, Paulo A V; Quartau, José A; Paulo, Octávio S; Seabra, Sofia G

    2014-01-01

    Philaenus spumarius is a widespread insect species in the Holarctic region. Here, by focusing on the mtDNA gene COI but also using the COII and Cyt b genes and the nuclear gene EF-1α, we tried to explain how and when its current biogeographic pattern evolved by providing time estimates of the main demographic and evolutionary events and investigating its colonization patterns in and out of Eurasia. Evidence of recent divergence and expansion events at less than 0.5 Ma ago indicate that climate fluctuations in the Mid-Late Pleistocene were important in shaping the current phylogeographic pattern of the species. Data support a first split and differentiation of P. spumarius into two main mitochondrial lineages: the "western", in the Mediterranean region and the "eastern", in Anatolia/Caucasus. It also supports a following differentiation of the "western" lineage into two sub-lineages: the "western-Mediterranean", in Iberia and the "eastern-Mediterranean" in the Balkans. The recent pattern seems to result from postglacial range expansion from Iberia and Caucasus/Anatolia, thus not following one of the four common paradigms. Unexpected patterns of recent gene-flow events between Mediterranean peninsulas, a close relationship between Iberia and North Africa, as well as high levels of genetic diversity being maintained in northern Europe were found. The mitochondrial pattern does not exactly match to the nuclear pattern suggesting that the current biogeographic pattern of P. spumarius may be the result of both secondary admixture and incomplete lineage sorting. The hypothesis of recent colonization of North America from both western and northern Europe is corroborated by our data and probably resulted from accidental human translocations. A probable British origin for the populations of the Azores and New Zealand was revealed, however, for the Azores the distribution of populations in high altitude native forests is somewhat puzzling and may imply a natural colonization

  2. New Mitochondrial and Nuclear Evidences Support Recent Demographic Expansion and an Atypical Phylogeographic Pattern in the Spittlebug Philaenus spumarius (Hemiptera, Aphrophoridae)

    PubMed Central

    Rodrigues, Ana S. B.; Silva, Sara E.; Marabuto, Eduardo; Silva, Diogo N.; Wilson, Mike R.; Thompson, Vinton; Yurtsever, Selçuk; Halkka, Antti; Borges, Paulo A. V.; Quartau, José A.; Paulo, Octávio S.; Seabra, Sofia G.

    2014-01-01

    Philaenus spumarius is a widespread insect species in the Holarctic region. Here, by focusing on the mtDNA gene COI but also using the COII and Cyt b genes and the nuclear gene EF-1α, we tried to explain how and when its current biogeographic pattern evolved by providing time estimates of the main demographic and evolutionary events and investigating its colonization patterns in and out of Eurasia. Evidence of recent divergence and expansion events at less than 0.5 Ma ago indicate that climate fluctuations in the Mid-Late Pleistocene were important in shaping the current phylogeographic pattern of the species. Data support a first split and differentiation of P. spumarius into two main mitochondrial lineages: the “western”, in the Mediterranean region and the “eastern”, in Anatolia/Caucasus. It also supports a following differentiation of the “western” lineage into two sub-lineages: the “western-Mediterranean”, in Iberia and the “eastern-Mediterranean” in the Balkans. The recent pattern seems to result from postglacial range expansion from Iberia and Caucasus/Anatolia, thus not following one of the four common paradigms. Unexpected patterns of recent gene-flow events between Mediterranean peninsulas, a close relationship between Iberia and North Africa, as well as high levels of genetic diversity being maintained in northern Europe were found. The mitochondrial pattern does not exactly match to the nuclear pattern suggesting that the current biogeographic pattern of P. spumarius may be the result of both secondary admixture and incomplete lineage sorting. The hypothesis of recent colonization of North America from both western and northern Europe is corroborated by our data and probably resulted from accidental human translocations. A probable British origin for the populations of the Azores and New Zealand was revealed, however, for the Azores the distribution of populations in high altitude native forests is somewhat puzzling and may imply a

  3. Pre-TCRα supports CD3-dependent reactivation and expansion of TCRα-deficient primary human T-cells

    PubMed Central

    Galetto, Román; Lebuhotel, Celine; Poirot, Laurent; Gouble, Agnès; Toribio, Maria L; Smith, Julianne; Scharenberg, Andrew

    2014-01-01

    Chimeric antigen receptor technology offers a highly effective means for increasing the anti-tumor effects of autologous adoptive T-cell immunotherapy, and could be made widely available if adapted to the use of allogeneic T-cells. Although gene-editing technology can be used to remove the alloreactive potential of third party T-cells through destruction of either the α or β T-cell receptor (TCR) subunit genes, this approach results in the associated loss of surface expression of the CD3 complex. This is nonetheless problematic as it results in the lack of an important trophic signal normally mediated by the CD3 complex at the cell surface, potentially compromising T-cell survival in vivo, and eliminating the potential to expand TCR-knockout cells using stimulatory anti-CD3 antibodies. Here, we show that pre-TCRα, a TCRα surrogate that pairs with TCRβ chains to signal proper TCRβ folding during T-cell development, can be expressed in TCRα knockout mature T-cells to support CD3 expression at the cell surface. Cells expressing pre-TCR/CD3 complexes can be activated and expanded using standard CD3/CD28 T-cell activation protocols. Thus, heterologous expression of pre-TCRα represents a promising technology for use in the manufacturing of TCR-deficient T-cells for adoptive immunotherapy applications. PMID:26015965

  4. Computational study of single-expansion-ramp nozzles with external burning

    NASA Technical Reports Server (NTRS)

    Yungster, Shaye; Trefny, Charles J.

    1992-01-01

    A computational investigation of the effects of external burning on the performance of single expansion ramp nozzles (SERN) operating at transonic speeds is presented. The study focuses on the effects of external heat addition and introduces a simplified injection and mixing model based on a control volume analysis. This simplified model permits parametric and scaling studies that would have been impossible to conduct with a detailed CFD analysis. The CFD model is validated by comparing the computed pressure distribution and thrust forces, for several nozzle configurations, with experimental data. Specific impulse calculations are also presented which indicate that external burning performance can be superior to other methods of thrust augmentation at transonic speeds. The effects of injection fuel pressure and nozzle pressure ratio on the performance of SERN nozzles with external burning are described. The results show trends similar to those reported in the experimental study, and provide additional information that complements the experimental data, improving our understanding of external burning flowfields. A study of the effect of scale is also presented. The results indicate that combustion kinetics do not make the flowfield sensitive to scale.

  5. Metamagnetic quantum criticality in Sr3Ru2O7 studied by thermal expansion.

    PubMed

    Gegenwart, P; Weickert, F; Garst, M; Perry, R S; Maeno, Y

    2006-04-01

    We report low-temperature thermal expansion measurements on the bilayer ruthenate Sr3Ru2O7 as a function of magnetic field applied perpendicular to the ruthenium-oxide planes. The field dependence of the c-axis expansion coefficient indicates the accumulation of entropy close to 8 T, related to an underlying quantum critical point. The latter is masked by two first-order metamagnetic transitions which bound a regime of enhanced entropy. Outside this region the singular thermal expansion behavior is compatible with the predictions of the itinerant theory for a two-dimensional metamagnetic quantum critical end point. PMID:16712009

  6. [The use of orthodontic goniometry to study apical expansion, using Pr. Planas' method: neuro-occlusal rehabilitation].

    PubMed

    Salvador Planas, C

    1992-01-01

    In this work, the method of orthodontic goniometry is used, which is a simple technique and not expensive, that allows us to determine the apical expansion in the studied models. 42 patients are studied by means of the techniques of Neuro-Occlusal Rehabilitation. We reach by this method expansion to the level of the apex as far as 12 mm in the lower arch and 11 mm in the upper arch. A simple statistic analysis is made which shows an average of expansions of 7.76 mm at crown level of the upper arch and 8.11 mm at apex level; at the crown level of lower arch we get 6.43 mm and apex level 5.8 mm. We think these results are interesting and they should make us study in depth the Neuro-Occlusal Rehabilitation and its principles. PMID:1341737

  7. Developmental Reading in Social Studies; Westward Expansion and Transportation in New York State. A Guide for Teachers, Grade 7, Revised.

    ERIC Educational Resources Information Center

    Cooper, Minna; And Others

    This guide is designed to provide seventh-grade social studies teachers with materials needed to present instruction in reading skills and to teach those facts, concepts, and attitudes which are the aim of social studies education. Entries on the subject of westward expansion and transportation in New York State are arranged by topics, and…

  8. Effect of surgically assisted rapid maxillary expansion on masticatory muscle activity: A pilot study

    PubMed Central

    Sverzut, Cássio E.; Martorelli, Karinna; Jabur, Roberto; Petri, Alice D.; Trivellato, Alexandre E.; Siéssere, Selma; Regalo, Simone C. H.

    2011-01-01

    Background: The aim of the present study was to analyze the electromyographic (EMG) activity of masseter and temporal muscles of adult patients submitted to surgically assisted rapid maxillary expansion (SARME) before and after the surgery. Materials and Methods: The sample consisted of 19 adults, with ages ranging from 20 to 47 years (mean 25.4 years), with bilateral posterior cross bite requiring SARME treatment. The electromyographic activity of masseter and temporal muscles was analyzed before treatment (T1) and after the surgical procedure (T2). The mean interval between the two electromyographic analyses was 15 days. Results: The muscular active was electromyographically analyzed during the clinical situation of habitual gum chewing (10 sec), dental clenching (4 sec), mouth opening and closing (10 sec), rest (10 sec), protrusion (10 sec), and right and left laterality (10 sec). The measured differences between T1 and T2 data were evaluated using the paired t-test (SPSS 17.0 for Windows). The electromyographic analysis showed that the activity of the masseter and temporal muscles decreased significantly after the SARME in all the clinical situations after the surgery. Conclusion: According to the results of the present study, individuals after SARME surgery presented patterns of electromyographic contraction similar to those developed by dentate individuals during the movements of mandibular excursion. PMID:23482404

  9. Studies of charge neutral FCC Lattice Gas with Yukawa Interaction and Accelerated Cartesian Expansion method

    NASA Astrophysics Data System (ADS)

    Huang, He

    In this thesis, I present the results of studies of the structural properties and phase transition of a charge neutral FCC Lattice Gas with Yukawa Interaction and discuss a novel fast calculation algorithm---Accelerated Cartesian Expansion (ACE) method. In the first part of my thesis, I discuss the results of Monte Carlo simulations carried out to understand the finite temperature (phase transition) properties and the ground state structure of a Yukawa Lattice Gas (YLG) model. In this model the ions interact via the potential q iqjexp(-kappar> ij)/rij where qi,j are the charges of the ions located at the lattice sites i and j with position vectors R i and Rj; rij = Ri-Rj, kappa is a measure of the range of the interaction and is called the screening parameter. This model approximates an interesting quaternary system of great current thermoelectric interest called LAST-m, AgSbPbmTem+2. I have also developed rapid calculation methods for the potential energy calculation in a lattice gas system with periodic boundary condition bases on the Ewald summation method and coded the algorithm to compute the energies in MC simulation. Some of the interesting results of the MC simulations are: (i) how the nature and strength of the phase transition depend on the range of interaction (Yukawa screening parameter kappa) (ii) what is the degeneracy of the ground state for different values of the concentration of charges, and (iii) what is the nature of two-stage disordering transition seen for certain values of x. In addition, based on the analysis of the surface energy of different nano-clusters formed near the transition temperature, the solidification process and the rate of production of these nano-clusters have been studied. In the second part of my thesis, we have developed two methods for rapidly computing potentials of the form R-nu. Both these methods are founded on addition theorems based on Taylor expansions. Taylor's series has a couple of inherent advantages: (i) it

  10. Universal Expansion.

    ERIC Educational Resources Information Center

    McArdle, Heather K.

    1997-01-01

    Describes a week-long activity for general to honors-level students that addresses Hubble's law and the universal expansion theory. Uses a discrepant event-type activity to lead up to the abstract principles of the universal expansion theory. (JRH)

  11. Army technology development. IBIS query. Software to support the Image Based Information System (IBIS) expansion for mapping, charting and geodesy

    NASA Technical Reports Server (NTRS)

    Friedman, S. Z.; Walker, R. E.; Aitken, R. B.

    1986-01-01

    The Image Based Information System (IBIS) has been under development at the Jet Propulsion Laboratory (JPL) since 1975. It is a collection of more than 90 programs that enable processing of image, graphical, tabular data for spatial analysis. IBIS can be utilized to create comprehensive geographic data bases. From these data, an analyst can study various attributes describing characteristics of a given study area. Even complex combinations of disparate data types can be synthesized to obtain a new perspective on spatial phenomena. In 1984, new query software was developed enabling direct Boolean queries of IBIS data bases through the submission of easily understood expressions. An improved syntax methodology, a data dictionary, and display software simplified the analysts' tasks associated with building, executing, and subsequently displaying the results of a query. The primary purpose of this report is to describe the features and capabilities of the new query software. A secondary purpose of this report is to compare this new query software to the query software developed previously (Friedman, 1982). With respect to this topic, the relative merits and drawbacks of both approaches are covered.

  12. Dental arch changes associated with rapid maxillary expansion: A retrospective model analysis study

    PubMed Central

    D’Souza, Ivor M; Kumar, H. C. Kiran; Shetty, K. Sadashiva

    2015-01-01

    Introduction: Transverse deficiency of the maxilla is a common clinical problem in orthodontics and dentofacial orthopedics. Transverse maxillary deficiency, isolated or associated with other dentofacial deformities, results in esthetic and functional impairment giving rise to several clinical manifestations such as asymmetrical facial growth, positional and functional mandibular deviations, altered dentofacial esthetics, adverse periodontal responses, unstable dental tipping, and other functional problems. Orthopedic maxillary expansion is the preferred treatment approach to increase the maxillary transverse dimension in young patients by splitting of the mid palatal suture. This orthopedic procedure has lately been subject of renewed interest in orthodontic treatment mechanics because of its potential for increasing arch perimeter to alleviate crowding in the maxillary arch without adversely affecting facial profile. Hence, the present investigation was conducted to establish a correlation between transverse expansion and changes in the arch perimeter, arch width and arch length. Methods: For this purpose, 10 subjects (five males, five females) were selected who had been treated by rapid maxillary expansion (RME) using hyrax rapid palatal expander followed by fixed mechanotherapy (PEA). Pretreatment (T1), postexpansion (T2), and posttreatment (T3) dental models were compared for dental changes brought about by RME treatment and its stability at the end of fixed mechanotherapy. After model measurements were made, the changes between T1–T2, T2–T3 and T1–T3 were determined for each patient. The mean difference between T1–T2, T2–T3 and T1–T3 were compared to assess the effects of RME on dental arch measurements. Results are expressed as mean ± standard deviation and are compared by repeated measures analysis of variance followed by a post-hoc test. Arch perimeter changes are correlated with changes in arch widths at the canine, premolar and molar regions

  13. Studies in Public Library Government, Organization, and Support. Final Report.

    ERIC Educational Resources Information Center

    Garrison, Guy

    This report consists of six individual reports that were done by staff members at the Library Research Center as part of the overall project. In Part I, "Financing Public Library Expansion: Case Studies of Three Defeated Bond Issue Referendums," Ruth G. Lindahl and William S. Berner analyze defeated library bond issue referendums in Champaign,…

  14. Simulation study supporting wastewater treatment plant upgrading.

    PubMed

    Hvala, N; Vrecko, D; Burica, O; Strazar, M; Levstek, M

    2002-01-01

    The paper presents a study where upgrading of an existing wastewater treatment plant was supported by simulation. The aim of the work was to decide between two technologies to improve nitrogen removal: a conventional activated sludge process (ASP) and a moving bed biofilm reactor (MBBR). To perform simulations, the mathematical models of both processes were designed. The models were calibrated based on data from ASP and MBBR pilot plants operating in parallel on the existing plant. Only two kinetic parameters needed to be adjusted to represent the real plant behaviour. Steady-state analyses have shown a similar efficiency of both processes in relation to carbon removal, but improved performance of MBBR in relation to nitrogen removal. Better performance of MBBR can be expected especially at low temperatures. Simulations have not confirmed the expected less volume required for the MBBR process. Finally, the MBBR was chosen for plant upgrading. The developed process model will be further used to evaluate the final plant configuration and to optimise the plant operating parameters. PMID:12361028

  15. Subnanometer poly-silicon gap structure formation: Comparison study between size expansion and size reduction

    NASA Astrophysics Data System (ADS)

    Hashim, U.; Nazwa, T.; Dhahi, Th. S.

    2012-06-01

    This study describes the comparison among the three fabrication methods of an array of poly-silicon nanogap structures. The three different methods are size expansion technique (SET), size reduction technique (SRT) and e-beam lithography (EBL) technique. Generally, SRT involves the breaking of the primarily pattern with no gap structure into nanogap scale. Conversely, SET engages in the process of enhancing the initially microgap pattern into nanogap scale. EBL refers to a lithographic process that uses a focused beam of electrons to form the circuit patterns needed for material deposition on or removal from the wafer. Using conventional photolithography, a procedure to fabricate poly-silicon nanogap structure on the wafer scale is designed. The nanogap (NG) fabrication procedure is based on the standard CMOS technology follows by employing both methods respectively. The lateral nanogap is introduced in the fabrication process using poly-silicon as an anode electrode. The similarity and distinction will be highlighted for each particular process involved in the fabrication of nanogap structures. The simple least-cost method does not require complicated nanolithography method of fabrication but it is still possible to measure the electrical properties of a single molecule. On top of that, these techniques can be applied extensively to different designs of nanogap structure down to several nanometer levels of dimensions. The innovative method reported here can easily produce a nanogap electrode in a reproducible manner.

  16. Impacts of impervious surface expansion on soil organic carbon - a spatially explicit study

    NASA Astrophysics Data System (ADS)

    Yan, Yan; Kuang, Wenhui; Zhang, Chi; Chen, Chunbo

    2015-12-01

    The rapid expansion of impervious surface areas (ISA) threatens soil organic carbon (SOC) pools in urbanized areas globally. The paucity of field observations on SOC under ISA (SOCISA), especially in dryland areas has limited our ability to assess the ecological impacts of ISA expansion. Based on systematically measured SOCISA (0-80 cm depth) of a dryland city, and land-use and land-cover change data derived from remotely sensed data, we investigated the magnitude and vertical/horizontal patterns of SOCISA and mapped the impact of ISA expansion on SOC storage. The mean SOCISA in the city was 5.36 ± 0.51 kg C m-2, lower than that observed in humid cities but much higher than that assumed in many regional carbon assessments. SOCISA decreased linearly as the soil depth or the horizontal distance from the open area increased. SOCISA accounted for over half of the city’s SOC stock, which decreased by 16% (primarily in the converted croplands) because of ISA expansion from 1990 to 2010. The impacts of the ISA expansion varied spatially, depending on the land- use and converted land-cover type.

  17. Impacts of impervious surface expansion on soil organic carbon--a spatially explicit study.

    PubMed

    Yan, Yan; Kuang, Wenhui; Zhang, Chi; Chen, Chunbo

    2015-01-01

    The rapid expansion of impervious surface areas (ISA) threatens soil organic carbon (SOC) pools in urbanized areas globally. The paucity of field observations on SOC under ISA (SOCISA), especially in dryland areas has limited our ability to assess the ecological impacts of ISA expansion. Based on systematically measured SOCISA (0-80 cm depth) of a dryland city, and land-use and land-cover change data derived from remotely sensed data, we investigated the magnitude and vertical/horizontal patterns of SOCISA and mapped the impact of ISA expansion on SOC storage. The mean SOCISA in the city was 5.36 ± 0.51 kg C m(-2), lower than that observed in humid cities but much higher than that assumed in many regional carbon assessments. SOCISA decreased linearly as the soil depth or the horizontal distance from the open area increased. SOCISA accounted for over half of the city's SOC stock, which decreased by 16% (primarily in the converted croplands) because of ISA expansion from 1990 to 2010. The impacts of the ISA expansion varied spatially, depending on the land- use and converted land-cover type. PMID:26642831

  18. Impacts of impervious surface expansion on soil organic carbon – a spatially explicit study

    PubMed Central

    Yan, Yan; Kuang, Wenhui; Zhang, Chi; Chen, Chunbo

    2015-01-01

    The rapid expansion of impervious surface areas (ISA) threatens soil organic carbon (SOC) pools in urbanized areas globally. The paucity of field observations on SOC under ISA (SOCISA), especially in dryland areas has limited our ability to assess the ecological impacts of ISA expansion. Based on systematically measured SOCISA (0–80 cm depth) of a dryland city, and land-use and land-cover change data derived from remotely sensed data, we investigated the magnitude and vertical/horizontal patterns of SOCISA and mapped the impact of ISA expansion on SOC storage. The mean SOCISA in the city was 5.36 ± 0.51 kg C m−2, lower than that observed in humid cities but much higher than that assumed in many regional carbon assessments. SOCISA decreased linearly as the soil depth or the horizontal distance from the open area increased. SOCISA accounted for over half of the city’s SOC stock, which decreased by 16% (primarily in the converted croplands) because of ISA expansion from 1990 to 2010. The impacts of the ISA expansion varied spatially, depending on the land- use and converted land-cover type. PMID:26642831

  19. 75 FR 16149 - Notice Of Amendment-OS ARRA Expansion of Research Capabilities To Study CE Complex Patients (R24...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-31

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF HEALTH AND HUMAN SERVICES Agency for Healthcare Research and Quality Notice Of Amendment--OS ARRA Expansion of Research Capabilities To Study CE Complex Patients (R24) SEP Meeting With this correction notice,...

  20. Studies of beam expansion and distributed Bragg reflector lasers for fiber optics and optical signal processing. Interim report

    SciTech Connect

    Garmire, E.M.

    1981-03-03

    Separate studies were performed on beam expansion and on Distributed Bragg Reflector (DBR) lasers preliminary to monolithic integration on GaAs substrates. These components are proposed for use in optical signal processing, for fiber optic sources and for high-brightness lasers.

  1. REPORT OF THE NAEB STUDY ON THE PROPOSED EXPANSION OF THE MIDWEST PROGRAM ON AIRBORNE TELEVISION INSTRUCTION.

    ERIC Educational Resources Information Center

    BRONSON, VERNON; AND OTHERS

    A TECHNICAL REPORT WAS PREPARED COVERING THE IMPACT OF AIRBORNE TELEVISION TRANSMISSION ON LAND-BASED UHF TELEVISION ASSIGNMENT PLANS. THE REPORT RELATED TO THE PROPOSED EXPANSION PLANS OF THE MIDWEST PROGRAM ON AIRBORNE TELEVISION INSTRUCTION (MPATI). EARLIER STUDIES BY THE NATIONAL ASSOCIATION OF EDUCATIONAL BROADCASTERS (NAEB) HAD LED TO THE…

  2. Inclusion of College Community in the Self: A Longitudinal Study of the Role of Self-Expansion in Students' Satisfaction

    ERIC Educational Resources Information Center

    Branand, Brittany; Mashek, Debra; Wray-Lake, Laura; Coffey, John K.

    2015-01-01

    Consistent with predictions derived from the self-expansion model, this 3-year longitudinal study found that participation in more college groups during sophomore year predicted increases in inclusion of the college community in the self at the end of junior year, which further predicted increases in satisfaction with the college experience at the…

  3. Intelligence support to arms control. Study project

    SciTech Connect

    Grisham, A.E.

    1990-04-09

    This paper argues that intelligence support is critical to the success of arms control. It identifies and describes the roles of intelligence in the arms control process, describes the existing intelligence organizational structure for arms control support, and identifies and analyzes issues. The roles include support to policy formulation, support to treaty negotiation, support to ratification, and finally, during verification, support for the implementation of the treaty through monitoring. The Director of Central Intelligence is responsible for monitoring, while the Arms Control and Disarmament Agency has responsibility for verification. Adjudication of conflicting interpretations occurs within the NSC committee structure. For several reasons, intelligence cannot be expected to do the actual verification of an arms control treaty. Most importantly, determination of an acceptable degree of confidence is always a political issue, although based on military judgement. Assigning intelligence responsibility for monitoring, rather than verification, helps to limit the politicization of intelligence. Issues identified during the research for this paper were analyzed within three subgroups: those inherent in the intelligence discipline; these must be managed successfully to limit adverse impact on intelligence products. Second, issues and challenges inherent in arms control bureaucratic relationships; these are best managed by keeping separate the actual monitoring analysis and verification this gives the West justification for caution, and reinforces the need for continued emphasis on verification.

  4. Barium silicates as high thermal expansion seals for solid oxide fuel cells studied by high-temperature X-ray diffraction (HT-XRD)

    NASA Astrophysics Data System (ADS)

    Kerstan, Marita; Rüssel, Christian

    Gas-tight seals between metals and ceramics in solid-oxide fuel cells can be fabricated from glasses which enable the crystallization of phases with high thermal expansion coefficients (mostly barium silicates). This article mainly reports on high-temperature X-ray diffraction studies on these silicates. It is shown that all barium silicates exhibit thermal expansion coefficients in the range from 10.5 to 15.4 × 10 -6 K -1 (100-800 °C). The expansions are strongly dependent on the respective crystallographic axis. The ortho- and metasilicates exhibit the largest thermal expansion coefficients. The coefficient of thermal expansion of a sealing glass is attributed to the thermal expansion of the crystalline phases and the residual glassy phase. The phase formation should carefully be controlled also with respect to aging. Crystalline phases with high coefficients of thermal expansion, such as the barium silicates, are advantageous as components in such sealing glasses.

  5. A study of the mechanism of laser welding defects in low thermal expansion superalloy GH909

    SciTech Connect

    Yan, Fei; Wang, Chunming Wang, Yajun; Hu, Xiyuan; Wang, Tianjiao; Li, Jianmin; Li, Guozhu

    2013-04-15

    In this paper, we describe experimental laser welding of low-thermal-expansion superalloy GH909. The main welding defects of GH909 by laser in the weld are liquation cracks and porosities, including hydrogen and carbon monoxide porosity. The forming mechanism of laser welding defects was investigated. This investigation was conducted using an optical microscope, scanning electron microscope, energy diffraction spectrum, X-ray diffractometer and other methodologies. The results demonstrated that porosities appearing in the central weld were related to incomplete removal of oxide film on the surface of the welding samples. The porosities produced by these bubbles were formed as a result of residual hydrogen or oxygenium in the weld. These elements failed to escape from the weld since laser welding has both a rapid welding speed and cooling rate. The emerging crack in the heat affected zone is a liquation crack and extends along the grain boundary as a result of composition segregation. Laves–Ni{sub 2}Ti phase with low melting point is a harmful phase, and the stress causes grain boundaries to liquefy, migrate and even crack. Removing the oxides on the surface of the samples before welding and carefully controlling technological parameters can reduce welding defects and improve formation of the GH909 alloy weld. - Highlights: ► It is a new process for the forming of GH909 alloy via laser welding. ► The forming mechanism of laser welding defects in GH909 has been studied. ► It may be a means to improve the efficiency of aircraft engine production.

  6. Defined Essential 8™ Medium and Vitronectin Efficiently Support Scalable Xeno-Free Expansion of Human Induced Pluripotent Stem Cells in Stirred Microcarrier Culture Systems.

    PubMed

    Badenes, Sara M; Fernandes, Tiago G; Cordeiro, Cláudia S M; Boucher, Shayne; Kuninger, David; Vemuri, Mohan C; Diogo, Maria Margarida; Cabral, Joaquim M S

    2016-01-01

    Human induced pluripotent stem (hiPS) cell culture using Essential 8™ xeno-free medium and the defined xeno-free matrix vitronectin was successfully implemented under adherent conditions. This matrix was able to support hiPS cell expansion either in coated plates or on polystyrene-coated microcarriers, while maintaining hiPS cell functionality and pluripotency. Importantly, scale-up of the microcarrier-based system was accomplished using a 50 mL spinner flask, under dynamic conditions. A three-level factorial design experiment was performed to identify optimal conditions in terms of a) initial cell density b) agitation speed, and c) to maximize cell yield in spinner flask cultures. A maximum cell yield of 3.5 is achieved by inoculating 55,000 cells/cm2 of microcarrier surface area and using 44 rpm, which generates a cell density of 1.4x106 cells/mL after 10 days of culture. After dynamic culture, hiPS cells maintained their typical morphology upon re-plating, exhibited pluripotency-associated marker expression as well as tri-lineage differentiation capability, which was verified by inducing their spontaneous differentiation through embryoid body formation, and subsequent downstream differentiation to specific lineages such as neural and cardiac fates was successfully accomplished. In conclusion, a scalable, robust and cost-effective xeno-free culture system was successfully developed and implemented for the scale-up production of hiPS cells. PMID:26999816

  7. Defined Essential 8™ Medium and Vitronectin Efficiently Support Scalable Xeno-Free Expansion of Human Induced Pluripotent Stem Cells in Stirred Microcarrier Culture Systems

    PubMed Central

    Badenes, Sara M.; Fernandes, Tiago G.; Cordeiro, Cláudia S. M.; Boucher, Shayne; Kuninger, David; Vemuri, Mohan C.; Diogo, Maria Margarida; Cabral, Joaquim M. S.

    2016-01-01

    Human induced pluripotent stem (hiPS) cell culture using Essential 8™ xeno-free medium and the defined xeno-free matrix vitronectin was successfully implemented under adherent conditions. This matrix was able to support hiPS cell expansion either in coated plates or on polystyrene-coated microcarriers, while maintaining hiPS cell functionality and pluripotency. Importantly, scale-up of the microcarrier-based system was accomplished using a 50 mL spinner flask, under dynamic conditions. A three-level factorial design experiment was performed to identify optimal conditions in terms of a) initial cell density b) agitation speed, and c) to maximize cell yield in spinner flask cultures. A maximum cell yield of 3.5 is achieved by inoculating 55,000 cells/cm2 of microcarrier surface area and using 44 rpm, which generates a cell density of 1.4x106 cells/mL after 10 days of culture. After dynamic culture, hiPS cells maintained their typical morphology upon re-plating, exhibited pluripotency-associated marker expression as well as tri-lineage differentiation capability, which was verified by inducing their spontaneous differentiation through embryoid body formation, and subsequent downstream differentiation to specific lineages such as neural and cardiac fates was successfully accomplished. In conclusion, a scalable, robust and cost-effective xeno-free culture system was successfully developed and implemented for the scale-up production of hiPS cells. PMID:26999816

  8. Thermal Expansion and Electrical Resistivity Studies of Nickel and ARMCO Iron at High Temperatures

    NASA Astrophysics Data System (ADS)

    Palchaev, D. K.; Murlieva, Zh. Kh.; Gadzhimagomedov, S. H.; Iskhakov, M. E.; Rabadanov, M. Kh.; Abdulagatov, I. M.

    2015-11-01

    The electrical resistance, ρ (T), and thermal expansion coefficient, β (T), of nickel and ARMCO iron have been simultaneously measured over a wide temperature range from (300 to 1100) K. The well-known standard four-probe potentiometric method was used for measurements of the electrical resistance. The thermal expansion coefficient was measured using the quartz dilatometer technique. Both techniques were combined in the same apparatus for simultaneous measurements of the electrical resistance and TEC for the same specimen. The combined expanded uncertainty of the electrical resistance and thermal expansion coefficient measurements at the 95 % confidence level with a coverage factor of k = 2 is estimated to be 0.5 % and (1.5 to 4.0) %, respectively. The distinct ρ (T) scattering contribution (phonon ρ _{ph}, magnetic ρ m, and residual ρ S) terms were separated and extracted from the measured total resistivity. The physical nature and details of the temperature dependence of the electrical resistance of solid materials and correct estimations of the contributions of various scattering mechanisms to the measured total resistivity were discussed in terms of the anharmonic effect. We experimentally found simple, universal, physically based, semiempirical linear correlations between the kinetic coefficient (electrical resistance) and a thermodynamic (equilibrium) property, the thermal expansion coefficient, of solid materials. The developed, physically based, correlation model has been successfully applied for nanoscale materials (ferromagnetic nickel nanowire). A new s-d-exchange interaction energy determination technique has been proposed.

  9. Supported Employment for Young People with Intellectual Disabilities Facilitated through Peer Support: A Pilot Study

    ERIC Educational Resources Information Center

    Kaehne, Axel; Beyer, Stephen

    2013-01-01

    The article reports the evaluation of a small-scale-supported employment project in a local authority in England. The study examined whether or not the peer support model could be used to deliver supported employment to a group of young people with intellectual disabilities. We utilised a mixed-method approach involving activity data, family…

  10. When enough is enough: how the decision was made to stop the FEAST trial: data and safety monitoring in an African trial of Fluid Expansion As Supportive Therapy (FEAST) for critically ill children

    PubMed Central

    2013-01-01

    In resource-rich countries, bolus fluid expansion is routinely used for the treatment of poor perfusion and shock, but is less commonly used in many African settings. Controversial results from the recently completed FEAST (Fluid Expansion As Supportive Therapy) trial in African children have raised questions about the use of intravenous bolus fluid for the treatment of shock. Prior to the start of the trial, the Independent data monitoring committee (IDMC) developed stopping rules for the proof of benefit that bolus fluid resuscitation would bring. Although careful safety monitoring was put in place, there was less expectation that bolus fluid expansion would be harmful and differential stopping rules for harm were not formulated. In July 2010, two protocol amendments were agreed to increase the sample size from 2,880 to 3,600 children, and to increase bolus fluid administration. There was a non-significant trend against bolus treatment, but although the implications were discussed, the IDMC did not comment on the results, or on the amendments, in order to avoid inadvertent partial unblinding of the study. In January 2011, the trial was stopped for futility, as the combined intervention arms had significantly higher mortality (relative risk 1.46, 95% CI 1.13 to 1.90, P = 0.004) than the control arm. The stopping rule for proof of benefit was not achieved, and the IDMC stopped the trial with a lower level of significance (P = 0.01) due to futility and an increased risk of mortality from bolus fluid expansion in children enrolled in the trial. The basis for this decision was that the local standard of care was not to use bolus fluid for the care of children with shock in these African countries, and this was a different standard of care to that used in the UK. These decisions emphasize two important principles: firstly, the IDMC should avoid inadvertent unblinding of the trial by commenting on amendments, and secondly, when considering stopping a trial, the IDMC

  11. Hypersonic Research Vehicle (HRV) real-time flight test support feasibility and requirements study. Part 1: Real-time flight experiment support

    NASA Technical Reports Server (NTRS)

    Rediess, Herman A.; Ramnath, Rudrapatna V.; Vrable, Daniel L.; Hirvo, David H.; Mcmillen, Lowell D.; Osofsky, Irving B.

    1991-01-01

    The results are presented of a study to identify potential real time remote computational applications to support monitoring HRV flight test experiments along with definitions of preliminary requirements. A major expansion of the support capability available at Ames-Dryden was considered. The focus is on the use of extensive computation and data bases together with real time flight data to generate and present high level information to those monitoring the flight. Six examples were considered: (1) boundary layer transition location; (2) shock wave position estimation; (3) performance estimation; (4) surface temperature estimation; (5) critical structural stress estimation; and (6) stability estimation.

  12. Space transportation system biomedical operations support study

    NASA Technical Reports Server (NTRS)

    White, S. C.

    1983-01-01

    The shift of the Space Transportation System (STS) flight tests of the orbiter vehicle to the preparation and flight of the payloads is discussed. Part of this change is the transition of the medical and life sciences aspects of the STS flight operations to reflect the new state. The medical operations, the life sciences flight experiments support requirements and the intramural research program expected to be at KSC during the operational flight period of the STS and a future space station are analyzed. The adequacy of available facilities, plans, and resources against these future needs are compared; revisions and/or alternatives where appropriate are proposed.

  13. Study on the influences of interaction behaviors between multiple combustion-gas jets on expansion characteristics of Taylor cavities

    NASA Astrophysics Data System (ADS)

    Xue, Xiaochun; Yu, Yonggang; Zhang, Qi

    2015-10-01

    The purpose of this study is to investigate means of controlling the interior ballistic stability of a bulk-loaded propellant gun (BLPG). Experiments on the interaction of twin combustion gas jets and liquid medium in a cylindrical stepped-wall combustion chamber are conducted in detail to obtain time series processes of jet expansion, and a numerical simulation under the same working conditions is also conducted to verify the reliability of the numerical method by comparing numerical results and experimental results. From this, numerical simulations on mutual interference and expansion characteristics of multiple combustion gas jets (four, six, and eight jets) in liquid medium are carried out, and the distribution characteristic of pressure, velocity, temperature, and evolutionary processes of Taylor cavities and streamlines of jet flow field are obtained in detail. The results of numerical simulations show that when different numbers of combustion gas jets expand in liquid medium, there are two different types of vortices in the jet flow field, including corner vortices of liquid phase near the step and backflow vortices of gas phase within Taylor cavities. Because of these two types of vortices, the radial expansion characteristic of the jets is increased, while changing numbers of combustion gas jets can restrain Kelvin-Helmholtz instability to a certain degree in jet expansion processes, which can at last realize the goal of controlling the interior ballistic stability of a BLPG. The optimum method for both suppressing Kelvin-Helmholtz instability and promoting radial expansion of Taylor cavities can be determined by analyzing the change of characteristic parameters in a jet flow field.

  14. Thermal expansion of single-walled carbon nanotube (SWNT) bundles: X-ray diffraction studies

    NASA Astrophysics Data System (ADS)

    Maniwa, Yutaka; Fujiwara, Ryuji; Kira, Hiroshi; Tou, Hideki; Kataura, Hiromichi; Suzuki, Shinzo; Achiba, Yohji; Nishibori, Eiji; Takata, Masaki; Sakata, Makoto; Fujiwara, Akihiko; Suematsu, Hiroyoshi

    2001-12-01

    Thermal expansion coefficient in single-walled carbon nanotube bundles was determined as (-0.15+/-0.20)×10-5 (1/K) for the tube diameter and (0.75+/-0.25)×10-5 (1/K) for the triangular lattice constant by means of x-ray scattering between 300 K to 950 K. The value for the intertube gap was (4.2+/-1.4)×10-5 (1/K), which is larger than 2.6×10-5 (1/K) for the c-axis thermal expansion in graphite. The results reveal the presence of a remarkably larger lattice anharmonicity in nanotube bundles than that of graphite. The small value for the tube diameter is consistent with the seamless tube structure formed by a strong covalent bond between carbon atoms comparable to that in graphite.

  15. MATURATION IN ACTION: CRYOEM STUDY OF A VIRAL CAPSID CAUGHT DURING EXPANSION

    PubMed Central

    Veesler, D.; Quispe, J.; Grigorieff, N.; Potter, C.S.; Carragher, B.; Johnson, J. E.

    2012-01-01

    SUMMARY Bacteriophage HK97 maturation involves discrete intermediate particle forms, comparable to transitional states in protein folding, before reaching its mature form. The process starts by formation of a metastable prohead, poised for exothermic expansion triggered by DNA packaging. During maturation, the capsid subunit transitions from a strained to a canonical tertiary conformation and this has been postulated to be the driving mechanism for initiating expansion via switching hexameric capsomer architecture from skewed to 6-fold symmetric. We report the subnanometer electron-cryomicroscopy reconstruction of the HK97 first expansion intermediate prior to any crosslink formation. This form displays 6-fold symmetric hexamers, but, unexpectedly, capsid subunit tertiary structures exhibit distortions comparable to the prohead forms. We propose that release of this coat subunit strain acts in synergy with the first crosslinks to drive forward maturation. Finally, we speculate that the energetic features of this transition may result from increased stability of intermediates during maturation via enhanced inter-subunit interactions. PMID:22748764

  16. A Longitudinal Study of Family Supports to Impaired Elderly.

    ERIC Educational Resources Information Center

    Johnson, Colleen Leahy; Catalano, Donald J.

    While research has documented the strengths of the family as a support system to the elderly, there is less understanding of what happens when supports are needed over an extended time. To study family care when support needs persist for a long period, 115 older adults were studied after discharge from the hospital and again about 8 months later.…

  17. Characterization of blood drawn rapidly for use in blood volume expansion studies: An animal model for simulated weightlessness

    NASA Technical Reports Server (NTRS)

    Chenault, V. Michelle; Lynch, Colleen D.; Morris, Mariana; Clodfelter, Jill; Hutchins, Phillip M.

    1990-01-01

    It was demonstrated that up to 8ml of blood can be drawn from donar rats without significantly increasing volume and stress sensitive hormones, and thus can be used for volume expansion studies. Infusion of whole blood allows more physiological changes that can be seen with volume expansion by saline or other ionic solutions. The infusion of whole blood to induce hypervolemia may provide an improved model to study the fluid balance and control mechanisms operative in weightlessness. Blood samples were drawn as quickly as possible from femoral artery catheters chronically implanted in Sprague Dawley rats and analyzed for hematocrit, plasma sodium, potassium, osmolality, corticosterone, epinepherine, norepinephrine, and vasopressin. The levels were found to be comparable to those of normal rats.

  18. Repulsive force support system feasibility study

    NASA Technical Reports Server (NTRS)

    Boom, R. W.; Abdelsalam, M. K.; Eyssa, Y. M.; Mcintosh, G. E.

    1987-01-01

    A new concept in magnetic levitation and control is introduced for levitation above a plane. A set of five vertical solenoid magnets mounted flush below the plane supports and controls the model in five degrees of freedom. The compact system of levitation coils is contained in a space 2.4 m (96 in) diameter by 1 m (40 in) deep with the top of the levitation system 0.9 m (36 in) below the center line of the suspended model. The levitated model has a permanent magnet core held in position by the five parallel superconductive solenoids symmetrically located in a circle. The control and positioning system continuously corrects for model position in five dimensions using computer current pulses superimposed on the levitation coil base currents. The conceptual designs include: superconductive and Nd-Fe-B permanent magnet model cores and levitation solenoids of either superconductive, cryoresistive, or room temperature windings.

  19. Supporting Calculations For Submerged Bed Scrubber Condensate Disposal Preconceptual Study

    SciTech Connect

    Pajunen, A. J.; Tedeschi, A. R.

    2012-09-18

    This document provides supporting calculations for the preparation of the Submerged Bed Scrubber Condensate Disposal Preconceptual Study report The supporting calculations include equipment sizing, Hazard Category determination, and LAW Melter Decontamination Factor Adjustments.

  20. Administrative Support and Alternatively Certified Teachers: A Mixed Methods Study on New Teacher Support and Retention

    ERIC Educational Resources Information Center

    Anderson, Erin M.

    2012-01-01

    A non-experimental study was conducted to examine the perceived administrative support needs of alternatively certified teachers and determine their impact on teacher retention. The study sought to identify the most valued administrative support needs of alternatively-certified teachers; to compare those needs by gender and tier teaching level;…

  1. Hanford personnel dosimeter supporting studies FY-1981

    SciTech Connect

    Not Available

    1982-08-01

    This report examined specific functional components of the routine external personnel dosimeter program at Hanford. Components studied included: dosimeter readout; dosimeter calibration; dosimeter field response; dose calibration algorithm; dosimeter design; and TLD chip acceptance procedures. Additional information is also presented regarding the dosimeter response to light- and medium-filtered x-rays, high energy photons and neutrons. This study was conducted to clarify certain data obtained during the FY-1980 studies.

  2. A comparative study of supervised learning as applied to acronym expansion in clinical reports.

    PubMed

    Joshi, Mahesh; Pakhomov, Serguei; Pedersen, Ted; Chute, Christopher G

    2006-01-01

    Electronic medical records (EMR) constitute a valuable resource of patient specific information and are increasingly used for clinical practice and research. Acronyms present a challenge to retrieving information from the EMR because many acronyms are ambiguous with respect to their full form. In this paper we perform a comparative study of supervised acronym disambiguation in a corpus of clinical notes, using three machine learning algorithms: the naïve Bayes classifier, decision trees and Support Vector Machines (SVMs). Our training features include part-of-speech tags, unigrams and bigrams in the context of the ambiguous acronym. We find that the combination of these feature types results in consistently better accuracy than when they are used individually, regardless of the learning algorithm employed. The accuracy of all three methods when using all features consistently approaches or exceeds 90%, even when the baseline majority classifier is below 50%. PMID:17238371

  3. Thermal expansion and decomposition of jarosite: a high-temperature neutron diffraction study

    SciTech Connect

    Xu, Hongwu; Zhao, Yusheng; Vogel, Sven C; Hickmott, Donald D; Daemen, Luke L; Hartl, Monika A

    2009-01-01

    The structure of deuterated jarosite, KFe{sub 3}(SO{sub 4}){sub 2}(OD){sub 6}, was investigated using time-of-flight neutron diffraction up to its dehydroxylation temperature. Rietveld analysis reveals that with increasing temperature, its c dimension expands at a rate {approx}10 times greater than that for a. This anisotropy of thermal expansion is due to rapid increase in the thickness of the (001) sheet of [Fe(O,OH){sub 6}] octahedra and [SO{sub 4}] tetrahedra with increasing temperature. Fitting of the measured cell volumes yields a coefficient of thermal expansion, a = a{sub 0} + a{sub 1} T, where a{sub 0} = 1.01 x 10{sup -4} K{sup -1} and a{sub 1} = -1.15 x 10{sup -7} K{sup -2}. On heating, the hydrogen bonds, O1{hor_ellipsis}D-O3, through which the (001) octahedral-tetrahedral sheets are held together, become weakened, as reflected by an increase in the D{hor_ellipsis}O1 distance and a concomitant decrease in the O3-D distance with increasing temperature. On further heating to 575 K, jarosite starts to decompose into nanocrystalline yavapaiite and hematite (as well as water vapor), a direct result of the breaking of the hydrogen bonds that hold the jarosite structure together.

  4. Mapping palm oil expansion using SAR to study the impact on the CO2 cycle

    NASA Astrophysics Data System (ADS)

    Pohl, Christine

    2014-06-01

    With Malaysia being the second largest palm oil producer in the world and the fact that palm oil ranks first in vegetable oil production on the world market the palm oil industry became an important factor in the country. Along with the expansion of palm oil across the nation causing deforestation of natural rain forest and conversion of peat land into plantation land there are several factors causing a tremendous increase in carbon dioxide (CO2) emissions. Main causes of CO2 emission apart from deforestation and peat-land conversion are the fires to create plantation land plus the fires burning waste products of the plantations itself. This paper describes a project that aims at the development of a remote sensing monitoring system to allow a continuous observation of oil palm plantation activities and expansion in order to be able to quantify CO2 emissions. The research concentrates on developing a spaceborne synthetic aperture radar information extraction system for palm oil plantations in the Tropics. This will lead to objective figures that can be used internationally to create a policy implementation plan to sustainably reduce CO2 emission in the future.

  5. Study of magnetic field expansion using a plasma generator for space radiation active protection

    NASA Astrophysics Data System (ADS)

    Jia, Xiang-Hong; Jia, Shao-Xia; Xu, Feng; Bai, Yan-Qiang; Wan, Jun; Liu, Hong-Tao; Jiang, Rui; Ma, Hong-Bo; Wang, Shou-Guo

    2013-09-01

    There are many active protecting methods including Electrostatic Fields, Confined Magnetic Field, Unconfined Magnetic Field and Plasma Shielding etc. for defending the high-energy solar particle events (SPE) and Galactic Cosmic Rays (GCR) in deep space exploration. The concept of using cold plasma to expand a magnetic field is the best one of all possible methods so far. The magnetic field expansion caused by plasma can improve its protective efficiency of space particles. One kind of plasma generator has been developed and installed into the cylindrical permanent magnet in the eccentric. A plasma stream is produced using a helical-shaped antenna driven by a radio-frequency (RF) power supply of 13.56 MHz, which exits from both sides of the magnet and makes the magnetic field expand on one side. The discharging belts phenomenon is similar to the Earth's radiation belt, but the mechanism has yet to be understood. A magnetic probe is used to measure the magnetic field expansion distributions, and the results indicate that the magnetic field intensity increases under higher increments of the discharge power.

  6. First-principles study of thermal expansion and thermomechanics of single-layer black and blue phosphorus

    NASA Astrophysics Data System (ADS)

    Sun, Hongyi; Liu, Gang; Li, Qingfang; Wan, X. G.

    2016-05-01

    The linear thermal expansion coefficients (LTEC) and thermomechanics of single-layer black and blue phosphorus are systematically studied using first-principles based on quasiharmonic approximation. We find the thermal expansion of black phosphorus is very anisotropic. The LTEC along zigzag direction has a turning from negative to positive at around 138 K, while the LTEC along armchair direction is positive (except below 8 K) and about 2.5 times larger than that along zigzag direction at 300 K. For blue phosphorus, the LTEC is negative in the temperature range from 0 to 350 K. In addition, we find that the Young's modulus and Poisson's ratio of black phosphorus along zigzag direction are 4 to 5 times larger than those along armchair direction within considered temperature range, showing a remarkable anisotropic in-plane thermomechanics property. The mechanisms of these peculiar thermal properties are also explored. This work provides a theoretical understanding of the thermal expansion and thermomechanics of this single layer phosphorus family, which will be useful in nanodevices.

  7. Personal Commitment, Support and Progress in Doctoral Studies

    ERIC Educational Resources Information Center

    Martinsuo, Miia; Turkulainen, Virpi

    2011-01-01

    Earlier research on doctoral education has associated study progress with the student's own capabilities and faculty support. The purpose of this study is to investigate how students' personal commitment and various forms of support, as well as their complementary effects, explain progress in doctoral studies. Data were collected by a…

  8. The Thermal Expansion Of Feldspars

    NASA Astrophysics Data System (ADS)

    Hovis, G. L.; Medford, A.; Conlon, M.

    2009-12-01

    Hovis and others (1) investigated the thermal expansion of natural and synthetic AlSi3 feldspars and demonstrated that the coefficient of thermal expansion (α) decreases significantly, and linearly, with increasing room-temperature volume (VRT). In all such feldspars, therefore, chemical expansion limits thermal expansion. The scope of this work now has been broadened to include plagioclase and Ba-K feldspar crystalline solutions. X-ray powder diffraction data have been collected between room temperature and 925 °C on six plagioclase specimens ranging in composition from anorthite to oligoclase. When combined with thermal expansion data for albite (2,3,4) a steep linear trend of α as a function of VRT emerges, reflecting how small changes in composition dramatically affect expansion behavior. The thermal expansion data for five synthetic Ba-K feldspars ranging in composition from 20 to 100 mole percent celsian, combined with data for pure K-feldspar (3,4), show α-VRT relationships similar in nature to the plagioclase series, but with a slope and intercept different from the latter. Taken as a group all Al2Si2 feldspars, including anorthite and celsian from the present study along with Sr- (5) and Pb-feldspar (6) from other workers, show very limited thermal expansion that, unlike AlSi3 feldspars, has little dependence on the divalent-ion (or M-) site occupant. This apparently is due to the necessitated alternation of Al and Si in the tetrahedral sites of these minerals (7), which in turn locks the tetrahedral framework and makes the M-site occupant nearly irrelevant to expansion behavior. Indeed, in feldspar series with coupled chemical substitution it is the change away from a 1:1 Al:Si ratio that gives feldspars greater freedom to expand. Overall, the relationships among α, chemical composition, and room-temperature volume provide useful predictive tools for estimating feldspar thermal expansion and give insight into the controls of expansion behavior in

  9. Powder Neutron Diffraction Study of the Thermal Expansion of Mirabilite, Na2SO4.10H2O

    NASA Astrophysics Data System (ADS)

    Brand, H. E.; Fortes, A. D.; Wood, I. G.; Knight, K. S.; Vocadlo, L.

    2006-12-01

    The presence of salts such as MgSO4 and Na2SO4 in chondritic meteorites has led to the suggestion that the water-rich icy moons of the Gas Giant planets are likely to be dominated by multiply hydrated salts such as Fritzsche's salt (MgSO4.11H2O), epsomite (MgSO4.7H2O) and mirabilite (Na2SO4.10H2O). Moreover, hydrated sulfates are likely to be important rock-forming minerals and water storage reservoirs on Mars. When constructing models of icy moons to explore their structure and evolution, it is therefore extremely important to know the phase behaviour and physical properties of the constituent materials under the appropriate pressure and temperature regimes (0 < P < 5 GPa, and 100 < T < 300 K). We are therefore engaged in a programme of study to measure the physical characteristics of candidate materials using a combination of neutron diffraction and computational chemistry. Neutrons are powerful probes of low molecular-weight solids, hydrogen-bearing species in particular, and their penetrative power allows one to study materials even in complex sample environments, such as pressure cells and cryostats. In practice, we measure the variation in molar volume of a solid as a function of pressure and temperature; this leads to derivatives in P and T, such as thermal expansivity and compressibility. Furthermore, we can observe phase transitions in situ, and collect diffraction data which may lead to a successful solution of the new polymorph's structure. In this contribution, we present the results of work to investigate the structure and thermoelastic properties of mirabilite. We have determined the ambient pressure thermal expansion tensor and investigated the low- temperature structural disorder of deuterated mirabilite from 4 - 300K. The volume expansion is positive and this is echoed by the expansion of the a and c axes. However, the b axis shows a small negative thermal expansion below 50K. Very similar behaviour is seen in MgSO4.7H2O and MgSO4.11H2O (Fortes et

  10. Experimental perfect-gas study of expansion-tube flow characteristics

    NASA Technical Reports Server (NTRS)

    Shinn, J. L.; Miller, C. G., III

    1978-01-01

    Results of an experimental investigation of expansion tube flow characteristics performed with helium test gas and acceleration gas are presented. The use of helium, eliminates complex real gas chemistry in the comparison of measured and predicted flow quantities. The driver gas was unheated helium at a nominal pressure of 33 MN sq m. The quiescent test gas pressure and quiescent acceleration gas pressure were varied from 0.7 to 50 kN/sq m and from 2.5 to 53 N/sq m, respectively. The effects of tube-wall boundary layer growth and finite secondary diaphragm opening time were examined through the variation of the quiescent gas pressures and secondary diaphragm thickness. Optimum operating conditions for helium test gas were also defined.

  11. Solid solubility and thermal expansion studies of uranium-europium mixed oxides

    NASA Astrophysics Data System (ADS)

    Venkata Krishnan, R.; Jogeswararao, G.; Panneerselvam, G.; Antony, M. P.; Ananthasivan, K.

    2015-10-01

    Uranium-europium mixed oxides (U1-yEuy)O2-x (y = 0.2, 0.4, 0.6, 0.65, 0.7, 0.75, 0.8) were prepared by citrate gel-combustion synthesis and characterized by using X-ray diffraction (XRD). The terminal solid solubility of EuO1.5 in UO2 is in the composition range 60-65 mol% EuO1.5. The coefficients of thermal expansions at 1973 K for (U1-yEuy)O2-x (y = 0.2, 0.4, 0.6) measured by using high-temperature X-ray diffraction (HTXRD) were found to be 15.80, 14.81 and 14.30 × 10-6 K-1 respectively.

  12. A Computing Infrastructure for Supporting Climate Studies

    NASA Astrophysics Data System (ADS)

    Yang, C.; Bambacus, M.; Freeman, S. M.; Huang, Q.; Li, J.; Sun, M.; Xu, C.; Wojcik, G. S.; Cahalan, R. F.; NASA Climate @ Home Project Team

    2011-12-01

    Climate change is one of the major challenges facing us on the Earth planet in the 21st century. Scientists build many models to simulate the past and predict the climate change for the next decades or century. Most of the models are at a low resolution with some targeting high resolution in linkage to practical climate change preparedness. To calibrate and validate the models, millions of model runs are needed to find the best simulation and configuration. This paper introduces the NASA effort on Climate@Home project to build a supercomputer based-on advanced computing technologies, such as cloud computing, grid computing, and others. Climate@Home computing infrastructure includes several aspects: 1) a cloud computing platform is utilized to manage the potential spike access to the centralized components, such as grid computing server for dispatching and collecting models runs results; 2) a grid computing engine is developed based on MapReduce to dispatch models, model configuration, and collect simulation results and contributing statistics; 3) a portal serves as the entry point for the project to provide the management, sharing, and data exploration for end users; 4) scientists can access customized tools to configure model runs and visualize model results; 5) the public can access twitter and facebook to get the latest about the project. This paper will introduce the latest progress of the project and demonstrate the operational system during the AGU fall meeting. It will also discuss how this technology can become a trailblazer for other climate studies and relevant sciences. It will share how the challenges in computation and software integration were solved.

  13. Supporting Off-Shore Students: A Preliminary Study

    ERIC Educational Resources Information Center

    Hussin, Virginia

    2007-01-01

    This paper reports on the first part of a recent research study into current initiatives to support the learning of non-English speaking background (NESB) transnational students in Asia who are studying off-shore at Australian universities. Learning support and development staff in 12 universities were surveyed using a questionnaire. The survey…

  14. Classmate Peer-Coaching: "A Study Buddy Support Scheme"

    ERIC Educational Resources Information Center

    Thalluri, Jyothi; O'Flaherty, Jackie A.; Shepherd, Paul L.

    2014-01-01

    This study had two aims: firstly, to determine whether participation in a peer support scheme called Study Buddy Support (SBS) improves pass rates of "at risk" students, and secondly, to examine the advantages of this model over hierarchical models where senior students tutor junior years. Bachelor of Nursing and Midwifery students in a…

  15. Expansion of DSSTox: Leveraging public data to create a semantic cheminformatics resource with quality annotations for support of U.S. EPA applications. (American Chemical Society)

    EPA Science Inventory

    The expansion of chemical-bioassay data in the public domain is a boon to science; however, the difficulty in establishing accurate linkages from CAS registry number (CASRN) to structure, or for properly annotating names and synonyms for a particular structure is well known. DSS...

  16. Small Study Supports New Stool-Based Colon Cancer Test

    MedlinePlus

    ... gov/news/fullstory_158388.html Small Study Supports New Stool-Based Colon Cancer Test Cologuard may help ... 2016 TUESDAY, April 19, 2016 (HealthDay News) -- A new, but small, study finds more evidence that a ...

  17. Experimental study of expansion and compression effects on the stability of Taylor vortex flow

    NASA Astrophysics Data System (ADS)

    Mansour, M.; Ali, M. H.; Abd El-Maksoud, R. M.

    2016-08-01

    The aim of the present experimental work is to determine the stability limits of Taylor cells by expanding and compressing the cells. The investigation was performed under laminar flow condition with a wide gap between an inner rotating cylinder and outer stationary cylinder. In order to allow the expansion and compression of the cells, the test rig was designed with a sliding upper end plate and a fixed lower end plate. The objectives are to determine the maximum and minimum size limits of each number of cells as well as the stability margin of them. Since, unstable cells have various oscillations and time dependent structures which change the behavior of the flow; the investigations of the stability limits is quite necessary to avoid the possible generation of unstable cells. In addition, the results are used to detect the number of cells that can be generated in the gap at different fluid column lengths. A stability map, locating the stability state of all possible numbers of cells, is assigned in the results. The map provides overlap zones between stable cells, in which the operating conditions will always lead to stable cells, even if the number of cells is changed by changing the initial conditions. Moreover, a rare phenomenon was observed during the compression process when the cells jumps unusually from six to two cells without passing through the four-cell mode.

  18. Second-order many-body perturbation study on thermal expansion of solid carbon dioxide.

    PubMed

    Li, Jinjin; Sode, Olaseni; Hirata, So

    2015-01-13

    An embedded-fragment ab initio second-order many-body perturbation (MP2) method is applied to an infinite three-dimensional crystal of carbon dioxide phase I (CO2-I), using the aug-cc-pVDZ and aug-cc-pVTZ basis sets, the latter in conjunction with a counterpoise correction for the basis-set superposition error. The equation of state, phonon frequencies, bulk modulus, heat capacity, Grüneisen parameter (including mode Grüneisen parameters for acoustic modes), thermal expansion coefficient (α), and thermal pressure coefficient (β) are computed. Of the factors that enter the expression of α, MP2 reproduces the experimental values of the heat capacity, Grüneisen parameter, and molar volume accurately. However, it proves to be exceedingly difficult to determine the remaining factor, the bulk modulus (B0), the computed value of which deviates from the observed value by 50-100%. As a result, α calculated by MP2 is systematically too low, while having the correct temperature dependence. The thermal pressure coefficient, β = αB0, which is independent of B0, is more accurately reproduced by theory up to 100 K. PMID:26574220

  19. An outdoor noise propagation study to predict the effect of a power plant expansion

    NASA Astrophysics Data System (ADS)

    Brasovan, Philip J.; Carney, Melinda J.; Cheenne, Dominique J.

    2005-04-01

    The results of an outdoor noise propagation model using CadnaA were compared to test data obtained on-site. The subject property is the central utility plant of a hospital located in Milwaukee, scheduled to be expanded with the addition of cooling towers. The modeled area was 400 m squared with a resolution grid of 2 m squared. The model was used to validate the observed test data as well as to predict the anticipated noise levels at completion of the expansion. A total of 11 points were investigated and the predicted data were found to match the test values within 2 dB at many locations. The data from the model show that the anticipated noise levels at the East property line will exceed those mandated by local ordinances by 3 dB. The model also predicts that the addition of a three meter absorbing barrier and the use of reduced noise fans for the six cell cooling system will bring the overall noise level from the system into compliance.

  20. A computational study of two-phase viscoelastic systems in a capillary tube with a sudden contraction/expansion

    NASA Astrophysics Data System (ADS)

    Izbassarov, Daulet; Muradoglu, Metin

    2016-01-01

    Two-phase viscoelastic systems are computationally studied in a pressure-driven flow with a sudden contraction and expansion using a finite-difference/front-tracking method. The effects of viscoelasticity in drop and bulk fluids are investigated including high Weissenberg and Reynolds number cases up to Wi = 100 and Re = 100. The Finitely Extensible Non-linear Elastic-Chilcott and Rallison (FENE-CR) model is used to account for the fluid viscoelasticity. Extensive computations are performed to examine drop dynamics for a wide range of parameters. It is found that viscoelasticity interacts with drop interface in a non-monotonic and complicated way, and the two-phase viscoelastic systems exhibit very rich dynamics especially in the expansion region. At high Re, the drop undergoes large deformation in the contraction region followed by strong shape oscillations in the downstream of the expansion. For a highly viscous drop, a re-entrant cavity develops in the contraction region at the trailing edge which, in certain cases, grows and eventually causes encapsulation of ambient fluid. The re-entrant cavity formation is initiated at the entrance of the contraction and is highly influenced by the viscoelasticity. Compared to the corresponding straight channel case, the effects of viscoelasticity are reversed in the constricted channel: Viscoelasticity in drop/continuous phase hinders/enhances formation of the re-entrant cavity and entrainment of ambient fluid into main drop. Encapsulation of ambient fluid into main droplet may be another route to produce a compound droplet in microfluidic applications.

  1. A SELF-SIMILAR EXPANSION MODEL FOR USE IN SOLAR WIND TRANSIENT PROPAGATION STUDIES

    SciTech Connect

    Davies, J. A.; Harrison, R. A.; Perry, C. H.; Davis, C. J.; Crothers, S. R.; Eyles, C. J.; Moestl, C.; Rollett, T.; Temmer, M.; Lugaz, N.; Savani, N. P.

    2012-05-01

    Since the advent of wide-angle imaging of the inner heliosphere, a plethora of techniques have been developed to investigate the three-dimensional structure and kinematics of solar wind transients, such as coronal mass ejections, from their signatures in single- and multi-spacecraft imaging observations. These techniques, which range from the highly complex and computationally intensive to methods based on simple curve fitting, all have their inherent advantages and limitations. In the analysis of single-spacecraft imaging observations, much use has been made of the fixed {phi} fitting (FPF) and harmonic mean fitting (HMF) techniques, in which the solar wind transient is considered to be a radially propagating point source (fixed {phi}, FP, model) and a radially expanding circle anchored at Sun centre (harmonic mean, HM, model), respectively. Initially, we compare the radial speeds and propagation directions derived from application of the FPF and HMF techniques to a large set of STEREO/Heliospheric Imager (HI) observations. As the geometries on which these two techniques are founded constitute extreme descriptions of solar wind transients in terms of their extent along the line of sight, we describe a single-spacecraft fitting technique based on a more generalized model for which the FP and HM geometries form the limiting cases. In addition to providing estimates of a transient's speed and propagation direction, the self-similar expansion fitting (SSEF) technique provides, in theory, the capability to estimate the transient's angular extent in the plane orthogonal to the field of view. Using the HI observations, and also by performing a Monte Carlo simulation, we assess the potential of the SSEF technique.

  2. High Enthalpy Studies of Capsule Heating in an Expansion Tunnel Facility

    NASA Technical Reports Server (NTRS)

    Dufrene, Aaron; MacLean, Matthew; Holden, Michael

    2012-01-01

    Measurements were made on an Orion heat shield model to demonstrate the capability of the new LENS-XX expansion tunnel facility to make high quality measurements of heat transfer distributions at flow velocities from 3 km/s (h(sub 0) = 5 MJ/kg) to 8.4 km/s (h(sub 0) = 36 MJ/kg). Thirty-nine heat transfer gauges, including both thin-film and thermocouple instruments, as well as four pressure gauges, and high-speed Schlieren were used to assess the aerothermal environment on the capsule heat shield. Only results from laminar boundary layer runs are reported. A major finding of this test series is that the high enthalpy, low-density flows displayed surface heating behavior that is observed to be consistent with some finite-rate recombination process occurring on the surface of the model. It is too early to speculate on the nature of the mechanism, but the response of the gages on the surface seems generally repeatable and consistent for a range of conditions. This result is an important milestone in developing and proving a capability to make measurements in a ground test environment and extrapolate them to flight for conditions with extreme non-equilibrium effects. Additionally, no significant, isolated stagnation point augmentation ("bump") was observed in the tests in this facility. Cases at higher Reynolds number seemed to show the greatest amount of overall increase in heating on the windward side of the model, which may in part be due to small-scale particulate.

  3. A Self-similar Expansion Model for Use in Solar Wind Transient Propagation Studies

    NASA Astrophysics Data System (ADS)

    Davies, J. A.; Harrison, R. A.; Perry, C. H.; Möstl, C.; Lugaz, N.; Rollett, T.; Davis, C. J.; Crothers, S. R.; Temmer, M.; Eyles, C. J.; Savani, N. P.

    2012-05-01

    Since the advent of wide-angle imaging of the inner heliosphere, a plethora of techniques have been developed to investigate the three-dimensional structure and kinematics of solar wind transients, such as coronal mass ejections, from their signatures in single- and multi-spacecraft imaging observations. These techniques, which range from the highly complex and computationally intensive to methods based on simple curve fitting, all have their inherent advantages and limitations. In the analysis of single-spacecraft imaging observations, much use has been made of the fixed phi fitting (FPF) and harmonic mean fitting (HMF) techniques, in which the solar wind transient is considered to be a radially propagating point source (fixed phi, FP, model) and a radially expanding circle anchored at Sun centre (harmonic mean, HM, model), respectively. Initially, we compare the radial speeds and propagation directions derived from application of the FPF and HMF techniques to a large set of STEREO/Heliospheric Imager (HI) observations. As the geometries on which these two techniques are founded constitute extreme descriptions of solar wind transients in terms of their extent along the line of sight, we describe a single-spacecraft fitting technique based on a more generalized model for which the FP and HM geometries form the limiting cases. In addition to providing estimates of a transient's speed and propagation direction, the self-similar expansion fitting (SSEF) technique provides, in theory, the capability to estimate the transient's angular extent in the plane orthogonal to the field of view. Using the HI observations, and also by performing a Monte Carlo simulation, we assess the potential of the SSEF technique.

  4. Comparative Study of Student Support Services of AIOU and UKOU

    ERIC Educational Resources Information Center

    Choudhry, Amtul Hafeez; Gujjar, Aijaz Ahmed; Hafeez, Muhammad Rashid

    2008-01-01

    This paper attempts to compare the availability, quality, similarities and differences of student support services in Allama Iqbal Open University (AIOU) and United Kingdom Open University (UKOU) and also to identify and enlist the deficiencies that AIOU students are facing in the student support services. The study found out that student support…

  5. A Comparative Study of Electronic Performance Support Systems

    ERIC Educational Resources Information Center

    Nguyen, Frank; Klein, James D.; Sullivan, Howard

    2005-01-01

    Electronic performance support systems (EPSS) deliver relevant support information to users while they are performing tasks. The present study examined the effect of different types of EPSS on user performance, attitudes, system use and time on task. Employees at a manufacturing company were asked to complete a procedural software task and…

  6. Application of Mythen detector: In-situ XRD study on the thermal expansion behavior of metal indium

    NASA Astrophysics Data System (ADS)

    Du, Rong; Chen, ZhongJun; Cai, Quan; Fu, JianLong; Gong, Yu; Wu, ZhongHua

    2016-07-01

    A Mythen detector has been equipped at the beamline 4B9A of Beijing Synchrotron Radiation Facility (BSRF), which is expected to enable BSRF to perform time-resolved measurement of X-ray diffraction (XRD) full-profiles. In this paper, the thermal expansion behavior of metal indium has been studied by using the in-situ XRD technique with the Mythen detector. The indium was heated from 303 to 433 K with a heating rate of 2 K/min. The in-situ XRD full-profiles were collected with a rate of one profile per 10 seconds. Rietveld refinement was used to extract the structural parameters. The results demonstrate that these collected quasi-real-time XRD profiles can be well used for structural analysis. The metal indium was found to have a nonlinear thermal expansion behavior from room temperature to the melting point (429.65 K). The a-axis of the tetragonal unit cell expands with a biquadratic dependency on temperature, while the c-axis contracts with a cubic dependency on temperature. By the time-resolved XRD measurements, it was observed that the [200] preferred orientation can maintain to about 403.15 K. While (110) is the last and detectable crystal plane just before melting of the polycrystalline indium foil. This study is not only beneficial to the application of metal indium, but also exhibits the capacity of in-situ time-resolved XRD measurements at the X-ray diffraction station of BSRF.

  7. Expansion Microscopy

    PubMed Central

    Chen, Fei; Tillberg, Paul W.; Boyden, Edward S.

    2014-01-01

    In optical microscopy, fine structural details are resolved by using refraction to magnify images of a specimen. Here we report the discovery that, by synthesizing a swellable polymer network within a specimen, it can be physically expanded, resulting in physical magnification. By covalently anchoring specific labels located within the specimen directly to the polymer network, labels spaced closer than the optical diffraction limit can be isotropically separated and optically resolved, a process we call expansion microscopy (ExM). Thus, this process can be used to perform scalable super-resolution microscopy with diffraction-limited microscopes. We demonstrate ExM with effective ~70 nm lateral resolution in both cultured cells and brain tissue, performing three-color super-resolution imaging of ~107 μm3 of the mouse hippocampus with a conventional confocal microscope. PMID:25592419

  8. Study of the causes and identification of the dominant mechanisms of failure of bellows expansion joints used in district heating system pipelines at MOEK

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Nikolaev, A. E.; Semenov, V. N.; Shipkov, A. A.; Shepelev, S. V.

    2015-06-01

    The results of laboratory studies of material properties and of numerical and analytical investigations to assess the stress-strain state of the metal of the bellows expansion joints used in the district heating system pipelines at MOEK subjected to corrosion failure are presented. The main causes and the dominant mechanisms of failure of the expansion joints have been identified. The influence of the initial crevice defects and the operating conditions on the features and intensity of destruction processes in expansion joints used in the district heating system pipelines at MOEK has been established.

  9. Learning strategy refinement reverses early sensory cortical map expansion but not behavior: Support for a theory of directed cortical substrates of learning and memory.

    PubMed

    Elias, Gabriel A; Bieszczad, Kasia M; Weinberger, Norman M

    2015-12-01

    Primary sensory cortical fields develop highly specific associative representational plasticity, notably enlarged area of representation of reinforced signal stimuli within their topographic maps. However, overtraining subjects after they have solved an instrumental task can reduce or eliminate the expansion while the successful behavior remains. As the development of this plasticity depends on the learning strategy used to solve a task, we asked whether the loss of expansion is due to the strategy used during overtraining. Adult male rats were trained in a three-tone auditory discrimination task to bar-press to the CS+ for water reward and refrain from doing so during the CS- tones and silent intertrial intervals; errors were punished by a flashing light and time-out penalty. Groups acquired this task to a criterion within seven training sessions by relying on a strategy that was "bar-press from tone-onset-to-error signal" ("TOTE"). Three groups then received different levels of overtraining: Group ST, none; Group RT, one week; Group OT, three weeks. Post-training mapping of their primary auditory fields (A1) showed that Groups ST and RT had developed significantly expanded representational areas, specifically restricted to the frequency band of the CS+ tone. In contrast, the A1 of Group OT was no different from naïve controls. Analysis of learning strategy revealed this group had shifted strategy to a refinement of TOTE in which they self-terminated bar-presses before making an error ("iTOTE"). Across all animals, the greater the use of iTOTE, the smaller was the representation of the CS+ in A1. Thus, the loss of cortical expansion is attributable to a shift or refinement in strategy. This reversal of expansion was considered in light of a novel theoretical framework (CONCERTO) highlighting four basic principles of brain function that resolve anomalous findings and explaining why even a minor change in strategy would involve concomitant shifts of involved brain

  10. Vaccine stability study design and analysis to support product licensure.

    PubMed

    Schofield, Timothy L

    2009-11-01

    Stability evaluation supporting vaccine licensure includes studies of bulk intermediates as well as final container product. Long-term and accelerated studies are performed to support shelf life and to determine release limits for the vaccine. Vaccine shelf life is best determined utilizing a formal statistical evaluation outlined in the ICH guidelines, while minimum release is calculated to help assure adequate potency through handling and storage of the vaccine. In addition to supporting release potency determination, accelerated stability studies may be used to support a strategy to recalculate product expiry after an unintended temperature excursion such as a cold storage unit failure or mishandling during transport. Appropriate statistical evaluation of vaccine stability data promotes strategic stability study design, in order to reduce the uncertainty associated with the determination of the degradation rate, and the associated risk to the customer. PMID:19717312

  11. Acoustical Studies of L-leucine and L-asparagine in aqueous electrolyte through thermal expansion coefficient

    NASA Astrophysics Data System (ADS)

    Jajodia, S.; Chimankar, O. P.; Kalambe, A.; Goswami, S. G.

    2012-12-01

    Amino acids are the building blocks of the proteins; their study provides important information, about the behaviour of larger biomolecules such as proteins. The properties of proteins such as their structure, solubility, denaturation, etc. are greatly influenced by electrolytes. Ultrasonic velocity and density values have been used for evaluation of thermal expansion coefficient and adiabatic compressibility for ternary systems (amino acid/salt + water) namely L-leucine / L-asparagine each in 1.5 M aqueous solution of NaCl used as solvent for various concentrations and at different temperatures (298.15K - 323.15K). Present paper reports the variation of various thermoacoustical parameters such as Moelwyn-Hughes parameter (C1), Beyer's non-linearity parameter (B/A), internal pressure (Pi), fractional free volume (f), available volume (Va), repulsive exponent (n), molecular constant (r), van der Waals' constant (b), Debye temperatue (θD), etc. have been computed from the thermal expansion coefficient with the change of concentration and temperature. The variations of all these parameters have been interpreted in terms of various intermolecular interactions such as strong, weak, charge transfer, complex formation, hydrogen bonding interaction. The structure making and breaking properties of the interacting components existing in proposed ternary systems. It shows the associating and dissociating tendency of the molecules of solute in solvent.The hetromolecular interactions are present in both the ternary systems.

  12. Study of the plasma expansion produced on ultra-thin foil targets with a high intensity and ultrashort laser pulse

    NASA Astrophysics Data System (ADS)

    Gnedyuk, Semen; Fourmaux, Sylvain; Buffechoux, Sebastien; Albertazzi, Bruno; Martin, Francois; Kieffer, Jean Claude

    2011-10-01

    INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes J3X 1S2, Québec, Canada LULI, UMR 7605, CNRS - CEA - Université Paris 6 - Ecole Polytechnique, Palaiseau, France Abstract: A high intensity ultrashort laser pulse, with an intensity of the order of 1019 W/cm2, focused onto a thin foil target generates a plasma and highly energetic ion (including proton) beams from its front and rear sides which propagate along the target normal. Another interest of laser plasma interaction with ultra-thin foil is the possibility to deposit energy in the entire laser absorption depth before any expansion thus enabling target isochoric heating. With a target thickness of 30 or 15 nm the laser pulse should interact in volume and enable to reach very high temperature while the target is still at solid density. The resulting cooling of the target will then be ultra-fast and potential X-ray emission should be ultrashort. The 100 TW class laser system at the Advanced Laser Light Source facility enables laser plasma interaction study with femtosecond laser pulses, ultra thin foil targets and high contrast laser pulse intensity ratio. We used a shadowgraph diagnostic with a femtosecond laser probe to characterize the plasma expansion.

  13. Novel Foraminal Expansion Technique

    PubMed Central

    Senturk, Salim; Ciplak, Mert; Oktenoglu, Tunc; Sasani, Mehdi; Egemen, Emrah; Yaman, Onur; Suzer, Tuncer

    2016-01-01

    The technique we describe was developed for cervical foraminal stenosis for cases in which a keyhole foraminotomy would not be effective. Many cervical stenosis cases are so severe that keyhole foraminotomy is not successful. However, the technique outlined in this study provides adequate enlargement of an entire cervical foraminal diameter. This study reports on a novel foraminal expansion technique. Linear drilling was performed in the middle of the facet joint. A small bone graft was placed between the divided lateral masses after distraction. A lateral mass stabilization was performed with screws and rods following the expansion procedure. A cervical foramen was linearly drilled medially to laterally, then expanded with small bone grafts, and a lateral mass instrumentation was added with surgery. The patient was well after the surgery. The novel foraminal expansion is an effective surgical method for severe foraminal stenosis. PMID:27559460

  14. Novel Foraminal Expansion Technique.

    PubMed

    Ozer, Ali Fahir; Senturk, Salim; Ciplak, Mert; Oktenoglu, Tunc; Sasani, Mehdi; Egemen, Emrah; Yaman, Onur; Suzer, Tuncer

    2016-08-01

    The technique we describe was developed for cervical foraminal stenosis for cases in which a keyhole foraminotomy would not be effective. Many cervical stenosis cases are so severe that keyhole foraminotomy is not successful. However, the technique outlined in this study provides adequate enlargement of an entire cervical foraminal diameter. This study reports on a novel foraminal expansion technique. Linear drilling was performed in the middle of the facet joint. A small bone graft was placed between the divided lateral masses after distraction. A lateral mass stabilization was performed with screws and rods following the expansion procedure. A cervical foramen was linearly drilled medially to laterally, then expanded with small bone grafts, and a lateral mass instrumentation was added with surgery. The patient was well after the surgery. The novel foraminal expansion is an effective surgical method for severe foraminal stenosis. PMID:27559460

  15. Thermal Expansion

    NASA Astrophysics Data System (ADS)

    Ventura, Guglielmo; Perfetti, Mauro

    All solid materials, when cooled to low temperatures experience a change in physical dimensions which called "thermal contraction" and is typically lower than 1 % in volume in the 4-300 K temperature range. Although the effect is small, it can have a heavy impact on the design of cryogenic devices. The thermal contraction of different materials may vary by as much as an order of magnitude: since cryogenic devices are constructed at room temperature with a lot of different materials, one of the major concerns is the effect of the different thermal contraction and the resulting thermal stress that may occur when two dissimilar materials are bonded together. In this chapter, theory of thermal contraction is reported in Sect. 1.2 . Section 1.3 is devoted to the phenomenon of negative thermal expansion and its applications.

  16. Accelerating the loop expansion

    SciTech Connect

    Ingermanson, R.

    1986-07-29

    This thesis introduces a new non-perturbative technique into quantum field theory. To illustrate the method, I analyze the much-studied phi/sup 4/ theory in two dimensions. As a prelude, I first show that the Hartree approximation is easy to obtain from the calculation of the one-loop effective potential by a simple modification of the propagator that does not affect the perturbative renormalization procedure. A further modification then susggests itself, which has the same nice property, and which automatically yields a convex effective potential. I then show that both of these modifications extend naturally to higher orders in the derivative expansion of the effective action and to higher orders in the loop-expansion. The net effect is to re-sum the perturbation series for the effective action as a systematic ''accelerated'' non-perturbative expansion. Each term in the accelerated expansion corresponds to an infinite number of terms in the original series. Each term can be computed explicitly, albeit numerically. Many numerical graphs of the various approximations to the first two terms in the derivative expansion are given. I discuss the reliability of the results and the problem of spontaneous symmetry-breaking, as well as some potential applications to more interesting field theories. 40 refs.

  17. The study of amplitude death in globally delay-coupled nonidentical systems based on order parameter expansion.

    PubMed

    Yao, Chenggui; Zou, Wei; Zhao, Qi

    2012-06-01

    The method of order parameter expansion is used to study the dynamical behavior in the globally delay-coupled nonidentical systems. Using the Landau-Stuart periodic system and Rössler chaotic oscillator to construct representative systems, the method can identify the boundary curves of amplitude death island analytically in the parameter space of the coupling and time delay. Furthermore, the parameter mismatch (diversity) effect on the size of island is investigated numerically. For the case of coupled chaotic Rössler systems with different timescales, the diversity increases the domain of death island monotonically. However, for the case of delay-coupled Landua-Stuart periodic systems with different frequencies, the average frequency turns out to be a critical role that determines change of size with the increase of diversity. PMID:22757556

  18. The study of amplitude death in globally delay-coupled nonidentical systems based on order parameter expansion

    NASA Astrophysics Data System (ADS)

    Yao, Chenggui; Zou, Wei; Zhao, Qi

    2012-06-01

    The method of order parameter expansion is used to study the dynamical behavior in the globally delay-coupled nonidentical systems. Using the Landau-Stuart periodic system and Rössler chaotic oscillator to construct representative systems, the method can identify the boundary curves of amplitude death island analytically in the parameter space of the coupling and time delay. Furthermore, the parameter mismatch (diversity) effect on the size of island is investigated numerically. For the case of coupled chaotic Rössler systems with different timescales, the diversity increases the domain of death island monotonically. However, for the case of delay-coupled Landua-Stuart periodic systems with different frequencies, the average frequency turns out to be a critical role that determines change of size with the increase of diversity.

  19. Third Culture Kids and College Support: A Case Study

    ERIC Educational Resources Information Center

    Holdren, Sarah Jennifer

    2013-01-01

    This single site case study applies the "Transition Cycle" framework (Pollock & Van Reken, 2009) to an institutionally-based, student-run support program for Third Culture Kids. The purpose of this study was to examine how Lewis and Clark College responded to the presence of Third Culture Kid, or Global Nomad, students on campus by…

  20. Ray-tracing study on the post-scanner variable beam expansion optics in a two-photon microscopy system

    NASA Astrophysics Data System (ADS)

    Kim, Do-Hyun; Welle, Cristin; Krauthamer, Victor

    2012-03-01

    Due to the low signal levels typical of two-photon microscopy (TPM) in biological samples, optical design optimization is critical. One of the most important factors is overfilling of the back aperture of the objective lens. A variable beam expander is commonly placed before the scanning mirrors to achieve this goal, however, this may cause degradation of image quality due to increased dispersion. Additionally, scanning mirror size restricts the degree of expansion, which often prevents the overfilling of objective lens back aperture. We investigated the implementation of variable beam expansion optics after the scanning mirrors. Ray-tracing analyses confirmed that the post-scanner beam expansion has two key advantages over the conventional pre-scanner beam expansion approach: decreasing the number of optical elements reduces pulse dispersion and reducing the size of the scanning mirror enables faster scanning. Resolution and aberration of a TPM with post-scanner beam expansion optics were analysed.

  1. The C9ORF72 expansion sizes in patients with psychosis: a population-based study on the Northern Finland Birth Cohort 1966.

    PubMed

    Solje, Eino; Miettunen, Jouko; Marttila, Riikka; Helisalmi, Seppo; Laitinen, Marjo; Koivumaa-Honkanen, Heli; Isohanni, Matti; Hiltunen, Mikko; Jääskeläinen, Erika; Remes, Anne M

    2016-04-01

    Patients with behavioral variant frontotemporal dementia (bvFTD) have many psychotic symptoms, especially at the onset of the disease. The C9ORF72 expansion is the most common genetic etiology observed with bvFTD and the prevalence of the expansion is notably high among Finnish bvFTD patients. The aim of this study was to evaluate the prevalence of the C9ORF72 expansion among the clearly characterized patients with psychosis, mainly schizophrenia, in early midlife. The C9ORF72 repeat sizes were analyzed in 130 (48% women) patients with psychosis from the Northern Finland Birth Cohort 1966 (N=11 017), the mean onset age being 27.9 (SD 7.0) years. Despite the high frequency of psychiatric symptoms in bvFTD patients and the extremely high prevalence of the C9ORF72 expansion in Finland, pathogenic expansion (>40 repeats) was not detected among the Northern Finland Birth Cohort 1966 individuals with psychosis, indicating that these disorders, especially schizophrenia before the age of 43 years, may not be associated with the C9ORF72 expansion. However, we identified four cases with intermediate size repeats (17-26), but the role of the intermediate repeats in the etiology of psychosis is unknown. PMID:26862832

  2. Amalgamation, Expansion, Quality Assurance and Innovations: A Case Study on a Key University in China

    ERIC Educational Resources Information Center

    Zhang, Jingning

    2010-01-01

    The Chinese higher education reform policies since 1993 have been pursued in a centralized, top-down manner, which some theorists characterize as "centralized decentralization" or governmental "steering at distance." This case-study dissertation has two purposes. First, is to evaluate the implementation or the "situated practices" of national…

  3. Analytical study of the external field for non-circular tokamak with multipole moment expansion approach

    SciTech Connect

    Okada, O.; DeLucia, J.; Okabayashi, M.

    1980-10-01

    An analytical study is made of the external field required to produce non-circular toroidal MHD equilibria. Here the external magnetic flux pattern is formulated with a series of multipole moments expanded around the magnetic axis. The present approach provides a common description of the external field characteristics of various devices rather than specifying location of poloidal coils. Furthermore, the preconceptual design of noncircular devices can be simplified since the arrangement of poloidal coil location is decoupled from the physics requirement.

  4. 3D Loops Evolutions (Twists And Expansions) And Magnetic Fields Interactions Studied With SOHO/EIT

    NASA Astrophysics Data System (ADS)

    Portier-Fozzani, Fabrice

    1999-10-01

    I will present some results from my PHD/Thesis. With SOHO/EIT, 3D Technics such as stereovision and "vision by shape" were developped to study coronal structures evolution. To discribe loops morphology, we adapted with M. Aschwanden a torus fit which include twist evolution. On a quick magnetic flux emergence (August 5th 1997), the twist were decreasing while the loop expand. During a long time evolution (July - August 1996), flaring activities were well correlated with sudden decrease in the twist. These 2 results correspond to the evolution expected with the Parker's formula (1977). Magnetic field lines interactions were also analyzed. From multi-wavelengths observations, we had studied some morphological and topological changes which can be interpreted as interactions between open and closed field lines (ie between Coronal Holes and Active Region Loops). Then, relationship between CME/Flares formation and our different instabilities studied were analyzed in the aim to find, in the futur, good criteria concerning space weather.

  5. A study of role expansion: a new GP role in cardiology care

    PubMed Central

    2014-01-01

    Background The National Health Service is reconfiguring health care services in order to meet the increasing challenge of providing care for people with long-term conditions and to reduce the demand on specialised outpatient hospital services by enhancing primary care. A review of cardiology referrals to specialised care and the literature on referral management inspired the development of a new GP role in Cardiology. This new extended role was developed to enable GPs to diagnose and manage patients with mild to moderate heart failure or atrial fibrillation and to use a range of diagnostics effectively in primary care. This entailed GPs participating in a four-session short course with on-going clinical supervision. The new role was piloted in a small number of GP practices in one county in England for four months. This study explores the impact of piloting the Extended Cardiology role on the GP’s role, patients’ experience, service delivery and quality. Methods A mixed methods approach was employed including semi-structured interviews with GPs, a patient experience survey, a quality review of case notes, and analysis on activity and referral data. Results The participating GPs perceived the extended GP role as a professional development opportunity that had the potential to reduce healthcare utilisation and costs, through a reduction in referrals, whilst meeting the patient’s wishes for the provision of care closer to home. Patient experience of the new GP service was positive. The standard of clinical practice was judged acceptable. There was a fall in referrals during the study period. Conclusion This new role in cardiology was broadly welcomed as a model of care by the participating GPs and by patients, because of the potential to improve the quality of care for patients in primary care and reduce costs. As this was a pilot study further development and continuing evaluation of the model is recommended. PMID:24885826

  6. Support after perinatal death: a study of support and counselling after perinatal bereavement.

    PubMed Central

    Forrest, G C; Standish, E; Baum, J D

    1982-01-01

    After an earlier study into the practical aspects of the management of perinatal death, a counselling service was introduced for parents whose baby had died in the perinatal period. The service was monitored, and the parents who received the service were compared with a group that did not. Fifty families were allocated randomly either to the counselling (supported) group or to the contrast group, who received routine hospital care. Assessment was carried out at six and 14 months after the death, using a semi-structured interview and two self-rating scales (the general health questionnaire and the Leeds scales). Two of 16 mothers in the supported group showed psychiatric disorder at six months, compared with 10 of 19 in the contrast group (p less than 0.01, Fisher's exact test). There was no significant difference between the two groups at 14 months, when 80% of all the women studied had recovered psychiatric symptoms. Socially isolated women and those who marital relations lacked intimacy had a higher incidence of psychiatric symptoms at six months. Early pregnancy (within six months) was associated with a higher incidence of psychiatric symptoms in the unsupported group. The duration of bereavement reaction after perinatal death was appreciably shortened by support and counselling. PMID:6814610

  7. Impacts of energy cane expansion on ecosystem services: A Florida case study

    NASA Astrophysics Data System (ADS)

    Bagley, J. E.; VanLoocke, A.; Jaiswal, D.; Bernacchi, C. J.; Long, S.

    2012-12-01

    There is a rising demand for sustainable and secure sources of energy. This demand is driving the development of second-generation biofuel crops across the United States. However, in a changing climate the capability of these crops to meet energy demands are uncertain. Additionally, the impacts of energy crop adoption on biophysical and biochemical ecosystem services need to be refined. Central Florida has been identified as a test bed for energy cane in anticipation of increased investment for energy crop production in the southeastern United States. Currently, the land cover in this region is characterized by pasturelands with relatively low rates of productivity and evapotranspiration. By replacing these lands with highly productive and irrigated energy cane significant perturbations to the local and regional budgets of water, energy, and carbon are anticipated. In this study, we extend the Agro-IBIS LSM with a mechanistic multilayer canopy model of biofuel crops to simulate inter-canopy fluxes of energy, moisture, and carbon. We validate the model using published leaf area, surface flux, and yield observations taken from studies that encompassed variable soil types, climatic conditions, and management decisions. This extended Agro-IBIS model is used to simulate the growth of energy cane in central Florida. Using this model we assess the potential impacts of large-scale changes in land cover on future ecosystem services for the region. In particular, we focus on how changes in atmospheric CO2 and temperature influence energy cane's regulation of surface fluxes and storage. Using a series of simulations that represent a range of climatic regimes we test how increased atmospheric carbon concentrations may enhance or diminish stresses associated with changes in regional climate, and how the physiological plant responses feedback on fluxes between the land surface and the atmosphere. This allows us to quantitatively evaluate how large-scale energy cane production

  8. What Do Breastfeeding Women Taking Herbal Galactagogues Perceive of Community Pharmacists’ Role in Breastfeeding Support? A Qualitative Study

    PubMed Central

    Sim, Tin Fei; Hattingh, H. Laetitia; Sherriff, Jillian; Tee, Lisa B.G.

    2015-01-01

    Information from pharmacists may affect breastfeeding womens’ decisions and choice of therapy. Community pharmacies remain one of the main sources of herbal medicines in Australia. In this study, we aimed to explore the perspectives of breastfeeding women on pharmacists’ role and whether there is potential for role expansion, as well as the facilitators and barriers in meeting their healthcare-related needs in the community pharmacy setting. Semi-structured in-depth interviews were conducted with 20 Western Australian women who were using one or more herbal galactagogues while breastfeeding. Participants’ views were classified into three major themes: (i) facilitators and (ii) barriers to an increased role of pharmacists; and (iii) implementation of breastfeeding related-services in community pharmacy settings. Overall perspectives of participants were positive about the potential for role expansion of pharmacists to meet their breastfeeding-related needs. Whilst most participants perceived community pharmacies as convenient sources of trusted information, some recognised barriers to an increased role of pharmacists. Several breastfeeding support services perceived to be useful in community pharmacy settings were identified. Issues raised highlighted areas of pharmacy practice which required improvement and revealed opportunities for expansion of pharmacists’ role to better support women and promote breastfeeding in the community. PMID:26371023

  9. A study on thermal barrier coatings including thermal expansion mismatch and bond coat oxidation

    NASA Technical Reports Server (NTRS)

    Chang, George C.; Phucharoen, Woraphat; Miller, Robert A.

    1986-01-01

    The present investigation deals with a plasma-sprayed thermal barrier coating (TBC) intended for high temperature applications to advanced gas turbine blades. Typically, this type of coating system consists of a zirconia-yttria ceramic layer with a nickel-chromium-aluminum bond coat on a superalloy substrate. The problem on hand is a complex one due to the fact that bond coat oxidation and thermal mismatch occur in the TBC. Cracking in the TBC has also been experimentally illustrated. A clearer understanding of the mechanical behavior of the TBC is investigated. The stress states in a model thermal barrier coating as it cools down in air is studied. The powerful finite element method was utilized to model a coating cylindrical specimen. Four successively refined finite element models were developed. Some results obtained using the first two models have been reported previously. The major accomplishment is the successful development of an elastic TBC finite element model known as TBCG with interface geometry between the ceramic layer and the bond coat. An equally important milestone is the near-completion of the new elastic-plastic TBC finite element model called TBCGEP which yielded initial results. Representative results are presented.

  10. Library Support Staff Position Classification Studies. SPEC Kit 252.

    ERIC Educational Resources Information Center

    Stambaugh, Laine, Comp.; Gomez, Joni, Comp.

    1999-01-01

    This survey of Association of Research Libraries (ARL) members gathered data on library support staff classification specifications in ARL libraries, the process for classifying these positions, and salary and title comparisons with similar positions outside of the library. It also asked when the last classification study was performed within the…

  11. Supporting Argumentation through Students' Questions: Case Studies in Science Classrooms

    ERIC Educational Resources Information Center

    Chin, Christine; Osborne, Jonathan

    2010-01-01

    This study explores how student-generated questions can support argumentation in science. Students were asked to discuss which of two graphs showing the change in temperature with time when ice is heated to steam was correct. Four classes of students, aged 12-14 years, from two countries, first wrote questions about the phenomenon. Then, working…

  12. Design study for a magnetically supported reaction wheel

    NASA Technical Reports Server (NTRS)

    Stocking, G.; Dendy, J.; Sabnis, A.

    1974-01-01

    Results are described of a study program in which the characteristics of a magnetically supported reaction wheel are defined. Tradeoff analyses are presented for the principal components, which are then combined in several reaction wheel design concepts. A preliminary layout of the preferred configuration is presented along with calculated design and performance parameters. Recommendations are made for a prototype development program.

  13. SUPPORT STUDIES IN FLUIDIZED-BED COMBUSTION, 1978 ANNUAL REPORT

    EPA Science Inventory

    The report gives results of laboratory- and process-scale EPA studies supporting the national development of atmospheric and pressurized fluidized-bed combustion (PFBC) of coal. Program objectives are: (1) to develop basic information needed to optimize the use of limestone for S...

  14. Computer-Supported Study Strategies for Purple People.

    ERIC Educational Resources Information Center

    Tenny, John L.

    1992-01-01

    Describes how the computer can support the study process of students variously described as "multivariate, nonlinear thinkers,""dyslexic,""learning disabled," and "purple people." Describes features of a Macintosh program called "Inspiration" that enables easy test entry and manipulation in a graphic mode, placing emphasis on the considerable…

  15. Supporting Low-Performing Schools in Ontario, Canada. Case Study

    ERIC Educational Resources Information Center

    Klinger, Don; Wade-Woolley, Lesly

    2012-01-01

    This case study describes the school turnaround programs underway as of summer 2009 in Ontario, Canada. In particular, it focuses on the policies and efforts of the Ontario Ministry of Education (MOE) and an MOE department, the Literacy and Numeracy Secretariat (LNS), to support low-performing schools across the province. The report begins with a…

  16. Characteristics of Teachers' Support on Learning: A Case Study

    ERIC Educational Resources Information Center

    Sardà, Anna; Márquez, Conxita; Sanmartí, Neus

    2014-01-01

    One of the problems in science education research is obtaining evidence that particular teacher support of learning helps achieve better academic results for students. Classroom ecology involves many variables that are difficult to control and, moreover, many results can only be seen in the medium term. The purpose of this case study on an expert…

  17. Specification aggregate quarry expansion: a case study demonstrating sustainable management of natural aggregate resources

    USGS Publications Warehouse

    Langer, William H.; Tucker, M.L.

    2003-01-01

    Many countries, provinces, territories, or states in the European Union, Australia, Canada, the United States, and elsewhere have begun implementing sustainability programs, but most of those programs stop short of sustainable management of aggregate resources. Sustainable practices do not always have to be conducted under the title of sustainability. This case study describes how Lafarge, a large multinational construction materials supplier, implemented the principles of sustainability even though there was an absence of existing local government policies or procedures addressing sustainable resource management. Jefferson County, Colorado, USA, is one of three counties in the six-county Denver, Colorado, region that has potentially available sources of crushed stone. Crushed stone comprises 30 percent of the aggregate produced in the area and plays a major role in regional aggregate resource needs. Jefferson County is home to four of the five crushed stone operations in the Denver region. Lafarge operates one of those four quarries. Lafarge recently proposed to expand its reserves by exchanging company-owned land for existing dedicated open space land adjacent to their quarry but owned by Jefferson County. A similar proposal submitted about 10 years earlier had been denied. Contrary to the earlier proposal, which was predicated on public relations, the new proposal was predicated on public trust. Although not explicitly managed under the moniker of sustainability, Lafarge used basic management principles that embody the tenets of sustainability. To achieve the goals of sustainable aggregate management where no governmental policies existed, Lafarge not only assumed their role of being a responsible corporate and environmental member of the community, but also assumed the role of facilitator to encourage and enable other stakeholders to responsibly resolve legitimate concerns regarding the Lafarge quarry proposal. Lafarge successfully presented an enlightened

  18. Exploration of Infertile Couples’ Support Requirements: A Qualitative Study

    PubMed Central

    Jafarzadeh-Kenarsari, Fatemeh; Ghahiri, Ataollah; Habibi, Mojtaba; Zargham-Boroujeni, Ali

    2015-01-01

    Background Due to high prevalence of infertility, increasing demand for infertility treatment, and provision of high quality of fertility care, it is necessary for healthcare professionals to explore infertile couples’ expectations and needs. Identification of these needs can be a prerequisite to plan the effective supportive interventions. The current study was, therefore, conducted in an attempt to explore and to understand infertile couples’ experiences and needs. Materials and Methods This is a qualitative study based on a content analysis ap- proach. The participants included 26 infertile couples (17 men and 26 women) and 7 members of medical personnel (3 gynecologists and 4 midwives) as the key informants. The infertile couples were selected from patients attending public and private infertility treatment centers and private offices of infertility specialists in Isfahan and Rasht, Iran, during 2012-2013. They were selected through purposive sampling method with maximum variation. In-depth unstructured interviews and field notes were used for data gathering among infertile couples. The data from medical personnel was collected through semi-structured interviews. The interview data were analyzed using conventional content analysis method. Results Data analysis revealed four main categories of infertile couples’ needs, including: i. Infertility and social support, ii. Infertility and financial support, iii. Infertility and spiritual support and iv. Infertility and informational support. The main theme of all these categories was assistance and support. Conclusion The study showed that in addition to treatment and medical needs, infertile couples encounter various challenges in different emotional, psychosocial, communicative, cognitive, spiritual, and economic aspects that can affect various areas of their life and lead to new concerns, problems, and demands. Thus, addressing infertile couples’ needs and expectations alongside their medical treatments as

  19. Project Orion, Environmental Control and Life Support System Integrated Studies

    NASA Technical Reports Server (NTRS)

    Russell, James F.; Lewis, John F.

    2008-01-01

    Orion is the next vehicle for human space travel. Humans will be sustained in space by the Orion subystem, environmental control and life support (ECLS). The ECLS concept at the subsystem level is outlined by function and technology. In the past two years, the interface definition with other subsystems has increased through different integrated studies. The paper presents the key requirements and discusses three recent studies (e.g., unpressurized cargo) along with the respective impacts on the ECLS design moving forward.

  20. Effects of salt rich diet in the obese Zucker rats: studies on renal function during isotonic volume expansion.

    PubMed

    Pamidimukkala, Jaya; Jandhyala, Bhagavan S

    2004-01-01

    Obese Zucker rats (OZR) are hyperinsulenemic, hyperglycemic and dyslipidemic and develop salt dependent hypertension. Since salt sensitivity is considered to be due to impaired handling of renal sodium excretion, these studies were conducted in the obese and lean Zucker rats (LZR) anesthetized with Inactin to evaluate renal function under basal conditions and during acute isotonic fluid volume expansion (VE). Mean Arterial blood pressure (MBP), heart rate (HR), renal blood flow(RBF) and glomerular filtration rate (GFR) were not significantly different between the lean Zucker rats fed normal diet or that fed salt rich diet(8% NaCI). However, basal UV and UNaV were significantly greater in the LZR fed high salt. During VE essentially identical increases occurred in GFR, UV and UNaV in both the lean groups. In the OZR fed salt rich diet also, there were no significant changes in the heart rate, RBF and GFR. However, arterial blood pressure of the OZR fed salt rich diet was significantly greater than that of the OZR on the normal diet as well as that of both the lean groups. Also, as in the LZR, basal UV and UNaV were significantly greater in the salt fed obese rats. During volume expansion there were no impairments in the ability of the obese groups fed normal or salt rich diet to eliminate sodium and water during volume load. In fact, the net sodium and water excretions during and 60 min after VE in both the obese groups were significantly greater than that of corresponding lean groups. Furthermore, these values in the OZR fed salt rich diet were significantly greater than that of the obese rats on normal salt diet perhaps due to the contribution of pressure natriuretic mechanisms'. These data demonstrate that although OZR are salt sensitive, the renal mechanisms that would collectively respond to acute isotonic VE were fully functional. An unexpected and a novel finding in these studies is that the salt rich diet, in addition to increasing arterial blood pressure

  1. Transverse effects on the nasomaxillary complex one year after rapid maxillary expansion as the only intervention: A controlled study

    PubMed Central

    Baratieri, Carolina da Luz; Alves, Maheus; Mattos, Claudia Trindade; Lau, Geórgia Wain Thi; Nojima, Lincoln Issamu; de Souza, Margareth Maria Gomes

    2014-01-01

    The aim of this study was to assess by means of cone-beam computed tomography (CBCT) scans the transverse effects on the nasomaxillary complex in patients submitted to rapid maxillary expansion (RME) using Haas expander in comparison to untreated individuals. This prospective controlled clinical study assessed 30 subjects (18 boys and 12 girls) with mixed dentition and during pubertal growth. The treated group was submitted to RME with Haas expander, retention for six months and a six-month follow-up after removal. The control group matched the treated group in terms of age and sex distribution. CBCT scans were taken at treatment onset and one year after the expander was activated. Maxillary first molars (U6) width, right and left U6 angulation, maxillary alveolar width, maxillary basal width, palatal alveolar width, palatal base width, right and left alveolar angulation, palatal area, nasal base width, nasal cavity width and inferior nasal cavity area on the posterior, middle and anterior coronal slices were measured with Dolphin Imaging Software(r) 11.5, except for the first two variables which were performed only on the posterior slice. All transverse dimensions increased significantly (P < 0.05) in the treated group in comparison to the control, except for alveolar angulation and inferior nasal cavity area (P > 0.05). Results suggest that increase of molar, maxillary, palatal and nasal transverse dimensions was stable in comparison to the control group one year after treatment with RME. PMID:25715720

  2. An experimental setup to study the expansion dynamics of laser blow-off plasma plume in variable transverse magnetic field

    NASA Astrophysics Data System (ADS)

    Kumar, Ajai; Chaudhari, Vishnu; Patel, Kiran; George, Sony; Sunil, S.; Singh, R. K.; Singh, Ranjeet

    2009-03-01

    In the present work we report generation of uniform and variable pulsed magnetic field in synchronization with pulsed plasma for the study of the expansion dynamics of laser blow-off (LBO) plasma plume. The experimental procedure for optimizing various parameters of the setup, e.g., the production of pulsed field and its synchronization with pulsed plasma and diagnostics system, is also reported. Until now the effect of magnetic field was studied using fixed field. The present setup, however, provides variable and uniform field in synchronization with the setup. A low cost time sequencing control module has been developed for the above purpose. Although the main emphasis is on the technical aspect of the setup, salient features of the effect of transverse magnetic field on the evolution features of the neutral and ionic species are also reported briefly. It is observed that LBO generated plume have a stronger correlation with the magnetic field in comparison to the conventional laser produced plasma experiments as reported earlier.

  3. Madelung and strain energies in the Ga1-xAlxN system: A study on the quality of cluster expansions

    NASA Astrophysics Data System (ADS)

    Ferreira, L. G.; Marques, M.; Teles, L. K.

    2006-08-01

    First-principles calculations within the local-density formalism were used to study the accuracy of cluster expansion techniques to predict the energy band gaps and enthalpy of the pseudobinary system Ga1-xAlxN , a technologically important alloy. The chosen pseudobinary system has the advantage of having small lattice mismatches, which minimizes the enthalpies of formation, and of being a semiconducting system with a direct band gap for any concentration x . Many different cluster expansion techniques were tested, some presenting clear advantages. The many cluster expansions were also compared against models of Madelung and strain energy, both long-range interactions. Though cluster expansions fail completely for the long-range Madelung interaction model, they behave remarkably well in the not so long-range strain model. The qualitative results for the strain model are similar to the results for the enthalpy and gap of the alloy system, thus giving us an assurance of our conclusions. Using only short-range interactions, all cluster expansions are clearly inadequate for the long-period orderings.

  4. Fundamental studies of supported bimetallic catalysts by NMR spectroscopy

    SciTech Connect

    Savargaonkar, N.

    1996-10-17

    Various hydrogenation reactions on transition metals are important commercially whereas certain hydrogenolysis reactions are useful from fundamental point of view. Understanding the hydrogen mobility and kinetics of adsorption-desorption of hydrogen is important in understanding the mechanisms of such reactions involving hydrogen. The kinetics of hydrogen chemisorption was studied by means of selective excitation NMR on silica supported Pt, Rh and Pt-Rh catalysts. The activation energy of hydrogen desorption was found to be lower on silica supported Pt catalysts as compared to Rh and Pt-Rh catalysts. It was found that the rates of hydrogen adsorption and desorption on Pt-Rh catalyst were similar to those on Rh catalyst and much higher as compared to Pt catalyst. The Ru-Ag bimetallic system is much simpler to study than the Pt-Rh system and serves as a model system to characterize more complicated systems such as the K/Ru system. Ag was found to decrease the amounts of adsorbed hydrogen and the hydrogen-to-ruthenium stoichiometry. Ag reduced the populations of states with low and intermediate binding energies of hydrogen on silica supported Ru catalyst. The rates of hydrogen adsorption and desorption were also lower on silica supported Ru-Ag catalyst as compared to Ru catalyst. This report contains introductory information, the literature review, general conclusions, and four appendices. An additional four chapters and one appendix have been processed separately for inclusion on the data base.

  5. Histological and histomorphometrical comparative study of β-tricalcium phosphate block grafts and periosteal expansion osteogenesis for alveolar bone augmentation.

    PubMed

    Yamauchi, K; Takahashi, T; Funaki, K; Hamada, Y; Yamashita, Y

    2010-10-01

    This study evaluated local tissue reaction around the β-tricalcium phosphate (β-TCP) block and compared results with β-TCP block grafting and periosteal expansion osteogenesis (PEO). The mandibular premolars were extracted from five dogs and buccal corticotomy was performed. Narrow alveolar ridge models were created at 4 weeks. The β-TCP block graft, such as veneer graft, was used on the right side and PEO using β-TCP block on the left side. Changes of alveolar width, histological findings and histomorphometrical analysis were evaluated. There were no problems with materials at any of the sites at any time. In both groups, the width increased after surgery and results were stable 8 weeks after surgery. Newly formed bone tissue was observed inside the β-TCP block in both sides. Histological findings differed especially at the division between mandibular bone and β-TCP block. Histomorphometric analyses revealed that β-TCP had been absorbed (mean decrease 28%) and new bone had formed (mean increase 43%) at 8 weeks postoperatively on both sides. The β-TCP block worked as a space-maker under the soft tissue, including the periosteum, and acted as a substitute for original bone. This bone substitute was effective material for bone augmentation in both methods. PMID:20615666

  6. Evaluation of the effects of modified bonded rapid maxillary expansion on occlusal force distribution: A pilot study

    PubMed Central

    Uzuner, Fatma Deniz; Odabasi, Hande; Acar, Secil; Tortop, Tuba; Darendeliler, Nilufer

    2016-01-01

    Objective: To evaluate the effects of modified bonded rapid maxillary expansion (RME) on occlusal force distribution. Materials and Methods: The sample included 12 patients (7 girls and 5 boys; mean age: 13.1 years) at the permanent dentition stage with bilateral posterior cross-bite. The patients were treated with a modified bonded RME appliance, activated twice a day. The study was terminated when the palatal cusps of the maxillary posterior teeth were occluding with the buccal cusps of the mandibular posterior teeth. The postretention period was 3 months. The T-Scan III device was used to analyze the percentages of occlusal force distribution, and records were taken at the pretreatment (T1), the postreatment (T2), and the postretention (T3) periods. Wilcoxon signed rank test was used for statistical analyses. Results: Incisors were most frequently without contact, followed by canines. The highest forces were seen in the second and first molar regions. A significant decrease was seen in total occlusal force during treatment (T1–T2); however, during retention, the force returned to its initial value, and no significant differences were found (T1–T3). No differences were found between right and left sides and in occlusal forces of the teeth in all time periods. Conclusion: The use of modified bonded RME decreases the total occlusal forces during the treatment period, but it does returns to its initial value after the postretention period. PMID:27011748

  7. Administrative support of novice science teachers: A multiple case study

    NASA Astrophysics Data System (ADS)

    Iacuone, Leann

    Novice science teachers leave the confines of colleges and universities to embark on a new adventure in education where they aim to influence young minds, make a difference in the world, and share their love for their content. They have learned their pedagogical skills with the support and assistance of fellow classmates, a supporting professor, and a cooperating teacher. These teachers enter their new place of employment and are met with many unexpected challenges, such as a lack of resources, no one to ask questions of, and a busy staff with already established relationships, causing them to feel an overall lack of support and resulting in many new teachers rethinking their career choice and leaving the field of education within 5 years of entering. This multiple-case study investigated the administrative support 4 novice science teachers received during an academic year and the novice teachers' perceptions of the support they received to answer the following research question: How do novice science teachers who have consistent interactions with administrators develop during their first year? To answer this question, semistructured interviews, reflection journals, observations, resumes, long-range plans, and student discipline referrals were collected. The findings from this study show novice science teachers who had incidents occur in the classroom requiring administrative assistance and guidance felt more confident in enforcing their classroom management policies and procedures as the year progressed to change student behavior. The novice science teachers perceived administrators who provided resources including technology, office supplies, science supplies, and the guidance of a mentor as supportive. Novice science teachers who engaged in dialogue after administrative observations, were provided the opportunity to attend professional development outside the district, and had a mentor who taught the same discipline made more changes to their instructional

  8. On Predtechensky and Mayorov model for the plume expansion dynamics study into an ambient gas during thin film deposition by laser ablation

    NASA Astrophysics Data System (ADS)

    Lafane, S.; Kerdja, T.; Abdelli-Messaci, S.; Malek, S.; Kechouane, M.

    2013-01-01

    The plume expansion dynamics for the Sm1- x Nd x NiO3 thin films deposition by a KrF excimer laser into oxygen atmosphere has been investigated using fast imaging. The study was carried out at 0.2 and 0.3 mbar of oxygen pressure and for different laser fluences. The plasma plume dynamics was analysed in the framework of Predtechensky and Mayorov (PM) model. It was found that PM model gives a general description of the plume expansion by using parameters (laser fluence and oxygen pressure) that ensure a hemispherical expansion of the plume. The latter was discussed in the framework of the shock-wave model and the plume dimensions.

  9. Geotechnical support and topical studies for nuclear waste geologic repositories

    SciTech Connect

    Not Available

    1989-01-01

    The present report lists the technical reviews and comments made during the fiscal year 1988 and summarizes the technical progress of the topical studies. In the area of technical assistance, there were numerous activities detailed in the next section. These included 24 geotechnical support activities, including reviews of 6 Study Plans (SP) and participation in 6 SP Review Workshops, review of one whole document Site Characterization Plan (SCP) and participation in the Assembled Document SCP Review Workshops by 6 LBL reviewers; the hosting of a DOE program review, the rewriting of the project statement of work, 2 trips to technical and planning meetings; preparation of proposed work statements for two new topics for DOE, and 5 instances of technical assistance to DOE. These activities are described in a Table in the following section entitled Geoscience Technical Support for Nuclear Waste Geologic Repositories.''

  10. Solid supported lipid bilayers: From biophysical studies to sensor design

    NASA Astrophysics Data System (ADS)

    Castellana, Edward T.; Cremer, Paul S.

    2006-11-01

    The lipid bilayer is one of the most eloquent and important self-assembled structures in nature. It not only provides a protective container for cells and sub-cellular compartments, but also hosts much of the machinery for cellular communication and transport across the cell membrane. Solid supported lipid bilayers provide an excellent model system for studying the surface chemistry of the cell. Moreover, they are accessible to a wide variety of surface-specific analytical techniques. This makes it possible to investigate processes such as cell signaling, ligand-receptor interactions, enzymatic reactions occurring at the cell surface, as well as pathogen attack. In this review, the following membrane systems are discussed: black lipid membranes, solid supported lipid bilayers, hybrid lipid bilayers, and polymer cushioned lipid bilayers. Examples of how supported lipid membrane technology is interfaced with array based systems by photolithographic patterning, spatial addressing, microcontact printing, and microfluidic patterning are explored. Also, the use of supported lipid bilayers in microfluidic devices for the development of lab-on-a-chip based platforms is examined. Finally, the utility of lipid bilayers in nanotechnology and future directions in this area are discussed.

  11. Assessment of Multiple Outcomes: An Evaluation Research Study of a Compensatory Early Childhood Program (Child Parent Centers and Child Parent Expansion Program).

    ERIC Educational Resources Information Center

    Eash, Maurice J.; And Others

    Child Parent Centers (CPC) have been established in selected disadvantaged areas to provide systematic educational experiences for preschool children as young as three years of age. This study provides an update on the current state of the CPC and its latest adaption, the Child Parent Expansion (CPX) Program. A three-year, longitudinal evaluation…

  12. Learning Achievement Packages in Social Studies - History: America a Unique Country; The Constitution; Westward Expansion of the United States; The American Indian. Calexico Intercultural Design.

    ERIC Educational Resources Information Center

    Sigliano, Ed; And Others

    In this publication are 4 social studies curriculum units aimed towards meeting the learning problems of students with special language handicaps in grades 7 through 11. Topics are: (1) America--A Unique Country; (2) The Constitution; (3) Westward Expansion of the United States; and (4) The American Indian. The Constitution and American Indian…

  13. The Effect of Expansion of Vision Span on Reading Speed: A Case Study of EFL Major Students at King Khalid University

    ERIC Educational Resources Information Center

    Kana'an, Basim Hamdan Ibrahim; Rab, Salahud Din Abdul; Siddiqui, Ahlullah

    2014-01-01

    The objective of the study is to demonstrate how and to what extent the expansion of vision span could be a decisive factor in enhancing the reading speed of EFL major students in the English Department at King Khalid University while maintaining their previous level of comprehension. The reading speed of students in the English Department at KKU…

  14. Message Quality and Standing to Support: A Qualitative Study of Support Messages Given to African-American HIV Survivors.

    PubMed

    Hample, Dale; Na, Ling

    2014-09-01

    We interviewed 25 African American HIV survivors who were as much as 25 years distant from their original diagnoses. We asked them to tell us about both supportive and non-supportive messages they received upon learning of their HIV status. Their interviews showed evidence of the importance of what we call standing to support. This idea is that particular roles (e.g., medical or family) imply a duty to offer constructive support. Anyone without such a standing is essentially irrelevant to the provision of support. Successful performance of a standing requires ability (to give information, to be empathetic, etc.) but the performance must be activated by the person who needs support. We found contrasts in the quality of messages originating in each of the standings we studied: medical, family, friends, relational partners, churches, and community centers. Dual consideration of supportive and non-supportive messages is productive in understanding the different standings to support. PMID:24228640

  15. Phonon and thermal expansion properties in Weyl semimetals MX (M = Nb, Ta; X = P, As): ab initio studies.

    PubMed

    Chang, Dahu; Liu, Yaming; Rao, Fengfei; Wang, Fei; Sun, Qiang; Jia, Yu

    2016-06-01

    Weyl semimetal (WSM) is a new type of topological quantum material for future spintronic devices. Using the first-principles density functional theory, we systematically investigated the thermal expansion properties, and the temperature dependence of isovolume heat capacity and bulk modulus in WSMs MX (M = Nb, Ta; X = P, As). We also presented the phonon dispersion curves and its variation under stress in MX and the anisotropic thermal expansion properties due to the anisotropic crystal structure in WSMs have been predicted in our calculations. Intriguing, we found that the heat capacities increase more rapidly with increasing temperature in the low temperature region for all MX. Furthermore, our results showed that the thermal expansion properties are determined mainly by the isovolume heat capacity at low temperatures, while the bulk modulus has the major effect at high temperatures. These results are useful for applications of WSMs in electronic and spintronic devices. PMID:27174542

  16. Implementation of Active Support in Victoria, Australia: An Exploratory Study

    ERIC Educational Resources Information Center

    Mansell, Jim; Beadle-Brown, Julie; Bigby, Christine

    2013-01-01

    Background: Active support is an effective intervention to support engagement of residents with intellectual disability in group homes. This survey explored resident characteristics of the people supported by organisations implementing active support, the provision of active support, its procedures and systems, and resident engagement in…

  17. Advanced Platform Systems Technology study. Volume 3: Supporting data

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The overall study effort proceeded from the identification of 106 technology topics to the selection of 5 for detail trade studies. The technical issues and options were evaluated through the trade process. Finally, individual consideration was given to costs and benefits for the technologies identified for advancement. Eight priority technology items were identified for advancement. Supporting data generated during the trade selection and trade study process were presented. Space platform requirements, trade study and cost benefits analysis, and technology advancement planning are advanced. The structured approach used took advantage of a number of forms developed to ensure that a consistent approach was employed by each of the diverse specialists that participated. These forms were an intrinsic part of the study protocol.

  18. Examining Urban Expansion Using Multi-Temporal Landsat Imagery: a Case Study of the Montreal Census Metropolitan Area from 1975 TO 2015, Canada

    NASA Astrophysics Data System (ADS)

    Ma, Lingfei; Zhao, He; Li, Jonathan

    2016-06-01

    Urban expansion, particularly the movement of residential and commercial land use to sub-urban areas in metropolitan areas, has been considered as a significant signal of regional economic development. In 1970s, the economic centre of Canada moved from Montreal to Toronto. Since some previous research have been focused on the urbanization process in Greater Toronto Area (GTA), it is significant to conduct research in its counterpart. This study evaluates urban expansion process in Montréal census metropolitan area (CMA), Canada, between 1975 and 2015 using satellite images and socio-economic data. Spatial and temporal dynamic information of urbanization process was quantified using Landsat imagery, supervised classification algorithms and the post-classification change detection technique. Accuracy of the Landsat-derived land use classification map ranged from 80% to 97%. The results indicated that continuous growth of built-up areas in the CMA over the study period resulted in a decrease in the area of cultivated land and vegetation. The results showed that urban areas expanded 442 km2 both along major river systems and lakeshores, as well as expanded from urban centres to surrounded areas. The analysis revealed that urban expansion has been largely driven by population growth and economic development. Consequently, the urban expansion maps produced in this research can assist decision-makers to promote sustainable urban development, and forecast potential changes in urbanization growth patterns.

  19. Forecasting deforestation and carbon emissions in tropical developing countries facing demographic expansion: a case study in Madagascar.

    PubMed

    Vieilledent, Ghislain; Grinand, Clovis; Vaudry, Romuald

    2013-06-01

    Anthropogenic deforestation in tropical countries is responsible for a significant part of global carbon dioxide emissions in the atmosphere. To plan efficient climate change mitigation programs (such as REDD+, Reducing Emissions from Deforestation and forest Degradation), reliable forecasts of deforestation and carbon dioxide emissions are necessary. Although population density has been recognized as a key factor in tropical deforestation, current methods of prediction do not allow the population explosion that is occurring in many tropical developing countries to be taken into account. Here, we propose an innovative approach using novel computational and statistical tools, including R/GRASS scripts and the new phcfM R package, to model the intensity and location of deforestation including the effect of population density. We used the model to forecast anthropogenic deforestation and carbon dioxide emissions in five large study areas in the humid and spiny-dry forests of Madagascar. Using our approach, we were able to demonstrate that the current rapid population growth in Madagascar (+3.39% per year) will significantly increase the intensity of deforestation by 2030 (up to +1.17% per year in densely populated areas). We estimated the carbon dioxide emissions associated with the loss of aboveground biomass to be of 2.24 and 0.26 tons per hectare and per year in the humid and spiny-dry forest, respectively. Our models showed better predictive ability than previous deforestation models (the figure of merit ranged from 10 to 23). We recommend this approach to reduce the uncertainty associated with deforestation forecasts. We also underline the risk of an increase in the speed of deforestation in the short term in tropical developing countries undergoing rapid population expansion. PMID:23789079

  20. The Global Expansion of Children's Television: A Case Study of the Adaptation of "Sesame Street" in Spain

    ERIC Educational Resources Information Center

    Moran, Kristin C.

    2006-01-01

    The landscape of children's programming is changing because of the increased exportation of children's television programs created in the USA. Networks have been aggressively marketing programs to an international audience through individual program sales and satellite network expansion. Some see problems as a result of the potential shift in…

  1. Thermal stability and thermal expansion studies of cubic fluorite-type MgF{sub 2} up to 135 GPa

    SciTech Connect

    Sun, X.W.; Song, T.; Wei, X.P.; Quan, W.L.; Liu, X.B.; Su, W.F.

    2014-04-01

    Highlights: • The thermal expansion of MgF{sub 2} with a fluorite-type structure has been investigated. • The quasi-harmonic Debye model is applied to take into account the thermal effect. • Particular attention is paid to the prediction of thermal expansion for the first time. - Abstract: The thermal expansion of MgF{sub 2} with a fluorite structure has been investigated at high pressures using plane-wave pseudopotential scheme within the local density approximation correction in the frame of density functional theory based on the analysis of thermal stability using classical molecular dynamics simulations up to 6500 K. To investigate the thermodynamic properties like as the P–V–T equation of state and volumetric thermal expansion coefficient α{sub V} of cubic fluorite-type MgF{sub 2} at extended pressure and temperature ranges, we apply the quasi-harmonic Debye model in which the phononic effects are considered. The P–V relationship and α{sub V} dependence of the pressure up to 135 GPa at different temperatures, and the V–T relationship and α{sub V} dependence of the temperature up to the melting temperature 1500 K at different pressures have been obtained.

  2. Atom cooling by nonadiabatic expansion

    SciTech Connect

    Chen Xi; Muga, J. G.; Campo, A. del; Ruschhaupt, A.

    2009-12-15

    Motivated by the recent discovery that a reflecting wall moving with a square-root-in-time trajectory behaves as a universal stopper of classical particles regardless of their initial velocities, we compare linear-in-time and square-root-in-time expansions of a box to achieve efficient atom cooling. For the quantum single-atom wave functions studied the square-root-in-time expansion presents important advantages: asymptotically it leads to zero average energy whereas any linear-in-time (constant box-wall velocity) expansion leaves a nonzero residual energy, except in the limit of an infinitely slow expansion. For finite final times and box lengths we set a number of bounds and cooling principles which again confirm the superior performance of the square-root-in-time expansion, even more clearly for increasing excitation of the initial state. Breakdown of adiabaticity is generally fatal for cooling with the linear expansion but not so with the square-root-in-time expansion.

  3. Life support system definition study for long duration planetary missions

    NASA Technical Reports Server (NTRS)

    Slavin, T.; Meyer, P.; Reysa, R.

    1989-01-01

    The development of a mission planners life support systems (LSS) guidebook for providing data on the impact of various LSS on mission parameters such as mass, power, and volume is discussed. The factors utilized to define LSS case study mission drivers, and driver and mission impact parameter definitions are described. An example of a guidebook table for a specific set of LSS drivers is provided. Four approaches for physical/chemical closed-loop LSS are examined. A preliminary LSS guidebook for a lunar base is presented.

  4. SAMICS support study. Volume 1: Cost account catalog

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The Jet Propulsion Laboratory (JPL) is examining the feasibility of a new industry to produce photovoltaic solar energy collectors similar to those used on spacecraft. To do this, a standardized costing procedure was developed. The Solar Array Manufacturing Industry Costing Standards (SAMICS) support study supplies the following information: (1) SAMICS critique; (2) Standard data base--cost account structure, expense item costs, inflation rates, indirect requirements relationships, and standard financial parameter values; (3) Facilities capital cost estimating relationships; (4) Conceptual plant designs; (5) Construction lead times; (6) Production start-up times; (7) Manufacturing price estimates.

  5. Supported Lipid Bilayer Technology for the Study of Cellular Interfaces

    PubMed Central

    Crites, Travis J.; Maddox, Michael; Padhan, Kartika; Muller, James; Eigsti, Calvin; Varma, Rajat

    2015-01-01

    Glass-supported lipid bilayers presenting freely diffusing proteins have served as a powerful tool for studying cell-cell interfaces, in particular, T cell–antigen presenting cell (APC) interactions, using optical microscopy. Here we expand upon existing protocols and describe the preparation of liposomes by an extrusion method, and describe how this system can be used to study immune synapse formation by Jurkat cells. We also present a method for forming such lipid bilayers on silica beads for the study of signaling responses by population methods, such as western blotting, flow cytometry, and gene-expression analysis. Finally, we describe how to design and prepare transmembrane-anchored protein-laden liposomes, following expression in suspension CHO (CHOs) cells, a mammalian expression system alternative to insect and bacterial cell lines, which do not produce mammalian glycosylation patterns. Such transmembrane-anchored proteins may have many novel applications in cell biology and immunology. PMID:26331983

  6. Support for Students Exposed to Trauma: A Pilot Study

    PubMed Central

    Jaycox, Lisa H.; Langley, Audra K.; Stein, Bradley D.; Wong, Marleen; Sharma, Priya; Scott, Molly; Schonlau, Matthias

    2010-01-01

    With high rates of trauma exposure among students, the need for intervention programs is clear. Delivery of such programs in the school setting eliminates key barriers to access, but there are few programs that demonstrate efficacy in this setting. Programs to date have been designed for delivery by clinicians, who are a scarce resource in many schools. This study describes preliminary feasibility and acceptability data from a pilot study of a new program, Support for Students Exposed to Trauma, adapted from the Cognitive Behavioral Intervention for Trauma in Schools (CBITS) program. Because of its “pilot” nature, all results from the study should be viewed as preliminary. Results show that the program can be implemented successfully by teachers and school counselors, with good satisfaction among students and parents. Pilot data show small reductions in symptoms among the students in the SSET program, suggesting that this program shows promise that warrants a full evaluation of effectiveness. PMID:20811511

  7. Range Expansion of Heterogeneous Populations

    NASA Astrophysics Data System (ADS)

    Reiter, Matthias; Rulands, Steffen; Frey, Erwin

    2014-04-01

    Risk spreading in bacterial populations is generally regarded as a strategy to maximize survival. Here, we study its role during range expansion of a genetically diverse population where growth and motility are two alternative traits. We find that during the initial expansion phase fast-growing cells do have a selective advantage. By contrast, asymptotically, generalists balancing motility and reproduction are evolutionarily most successful. These findings are rationalized by a set of coupled Fisher equations complemented by stochastic simulations.

  8. Summary of HEDL Fusion Reactor Safety Support studies

    SciTech Connect

    Muhlestein, L.D.; Jeppson, D.W.; Barreca, J.R.

    1981-01-01

    The HEDL Fusion Reactor Safety Support studies are focused on characterizing blanket-coolant-material reactions for deuterium-tritium fusion reactor designs. The objective is to determine and examine potential safety and environmental issues associated with proposed blanket/coolant combinations under postulated accident conditions. The first studies considered liquid lithium as both blanket and coolant, and examined liquid lithium-material reactions. Liquid lithium reactions with oxygen, nitrogen, and various concretes have been characterized. Evaluations of lithium reaction extinguishment methods, lithium aerosol generation and collection, and the volatilization and transport of radioactive materials in connection with lithium-air reactions have been completed. Lithium compound blanket material reactions with water, a prime coolant candidate, have been characterized in terms of energy and gas release rates. Blanket materials considered were lithium aluminate, lithium oxide, lithium zirconate, lithium silicate, and lithium lead alloys (Li/sub 7/Pb/sub 2/ and Li/sub 17/Pb/sub 83/).

  9. An experimental study of laser supported hydrogen plasmas

    NASA Technical Reports Server (NTRS)

    Vanzandt, D. M.; Mccay, T. D.; Eskridge, R. H.

    1984-01-01

    The rudiments of a rocket thruster which receives its enthalpy from an energy source which is remotely beamed from a laser is described. An experimental study now partially complete is discussed which will eventually provide a detailed understanding of the physics for assessing the feasibility of using hydrogen plasmas for accepting and converting this energy to enthalpy. A plasma ignition scheme which uses a pulsed CO2 laser has been developed and the properties of the ignition spark documented, including breakdown intensities in hydrogen. A complete diagnostic system capable of determining plasma temperature and the plasma absorptivity for subsequent steady state absorption of a high power CO2 laser beam are developed and demonstrative use is discussed for the preliminary case study, a two atmosphere laser supported argon plasma.

  10. Pauli mechanism for universal expansion

    NASA Astrophysics Data System (ADS)

    Hayes, Robert

    2016-03-01

    By assuming the cosmological principle includes the Pauli exclusion principle (PEP) and that existence occurred post big bang within Planck time and length scales, a model for universal expansion can be argued. All Fermionic matter is forced by the PEP to make a quantum transition to minimally orthogonal states scaling with that predicted for a neutron star (NS). This predicts the minimum inflation time scale to be on the order of 1e-44 s. A coupling of primordial low mass neutrinos to have wavelengths comparable to or greater than the Hubble length is also postulated as a contributor to universal expansion. The model provides a mechanistic explanation for universal expansion using only physics from the standard model. This work supported in part under federal Grant NRC-HQ-84-14-G-0059.