Sample records for acetate eva copolymer

  1. Applications of ethylene vinyl acetate copolymers (EVA) in drug delivery systems.

    PubMed

    Schneider, Christian; Langer, Robert; Loveday, Donald; Hair, Dirk

    2017-09-28

    The potential for use of polymers in controlled drug delivery systems has been long recognized. Since their appearance in the literature, a wide range of degradable and non-degradable polymers have been demonstrated in drug delivery devices. The significance and features of ethylene-vinyl acetate (EVA) copolymers in initial research and development led to commercial drug delivery systems. This review examines the breadth of EVA use in drug delivery, and will aid the researcher in locating key references and experimental results, as well as understanding the features of EVA as a highly versatile, biocompatible polymer for drug delivery devices. Topics will include. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Preparation and Properties of Ethylene Vinyl Acetate Copolymer/Silica Nanocomposites in Presence of EVA-g-Acrylic Acid.

    PubMed

    Tham, Do Quang; Tuan, Vu Manh; Thanh, Dinh Thi Mai; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Trang, Nguyen Thi Thu; Hang, To Thi Xuan; Huong, Ho Thu; Dung, Nguyen Thi Kim; Hoang, Thai

    2015-04-01

    Here we report a facile approach to enhance the dispersibility of ethylene vinyl acetate copolymer (EVA)/silica nanocomposites (for the EVA/silica nanocomposites and interaction between silica nanoparticles (nanosilica) and EVA by adding EVA-g-acrylic acid (EVAgAA) as a compatibilizer, which was formed by grafting acrylic acid onto EVA chains with the aid of dicumyl peroxide). The above nanocomposites with and without EVAgAA were prepared by melt mixing in a Haake intermixer with different contents of silica and EVAgAA. Their structure and morphology were characterized by Fourier transform infra-red (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), and the mechanical, rheological, dielectrical, and flammability properties of the nanocomposites were also investigated. The FT-IR spectra of the nanocomposites confirmed the formation of hydrogen bonds between the surface silanol groups of nanosilica and C=O groups of EVA and/or EVAgAA. The presence of EVAgAA remarkably increased the intensity of hydrogen bonding between nanosilica and EVA which not only enhanced the dispersion of nanosilica in EVA matrix but also increased the mechanical, viscosity and storage modulus of EVA/silica nanocomposites. In addition, the flammability of EVA/silica nanocomposites is also significantly reduced after the functionalization with EVAgAA. However, the mechanical properties of EVA/silica nanocomposites tended to level off when its content was above 1.5 wt.%. It has also been found that the dielectric constant value of the EVA/EVAgAA/silica nanocomposites is much lower than that of the EVA/silica nanocomposites, which is another evidence of the hydrogen bonding formation between EVAgAA and nanosilica.

  3. Pre-dispersed organo-montmorillonite (organo-MMT) nanofiller: Morphology, cytocompatibility and impact on flexibility, toughness and biostability of biomedical ethyl vinyl acetate (EVA) copolymer.

    PubMed

    Osman, Azlin F; M Fitri, Tuty Fareyhynn; Rakibuddin, Md; Hashim, Fatimah; Tuan Johari, Syed Ahmad Tajudin; Ananthakrishnan, Rajakumar; Ramli, Rafiza

    2017-05-01

    Polymer-clay based nanocomposites are among the attractive materials to be applied for various applications, including biomedical. The incorporation of the nano sized clay (nanoclay) into polymer matrices can result in their remarkable improvement in mechanical, thermal and barrier properties as long as the nanofillers are well exfoliated and dispersed throughout the matrix. In this work, exfoliation strategy through pre-dispersing process of the organically modified montmorillonite (organo-MMT) nanofiller was done to obtain ethyl vinyl acetate (EVA) nanocomposite with improved flexibility, toughness, thermal stability and biostability. Our results indicated that the degree of organo-MMT exfoliation affects its cytotoxicity level and the properties of the resulting EVA nanocomposite. The pre-dispersed organo-MMT by ultrasonication in water possesses higher degree of exfoliation as compared to its origin condition and significantly performed reduced cytotoxicity level. Beneficially, this nanofiller also enhanced the EVA flexibility, thermal stability and biostability upon the in vitro exposure. We postulated that these were due to plasticizing effect and enhanced EVA-nanofiller interactions contributing to more stable chemical bonds in the main copolymer chains. Improvement in copolymer flexibility is beneficial for close contact with human soft tissue, while enhancement in toughness and biostability is crucial to extend its life expectancy as insulation material for implantable device. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Assessment of Ethylene Vinyl-Acetato Copolymer (EVA) Samples Bombarded by Gamma Radiation via Linearity Analyses

    NASA Astrophysics Data System (ADS)

    de Oliveira, L. N.; do Nascimento, E. O.; Schimidt, F.; Antonio, P. L.; Caldas, L. V. E.

    2018-03-01

    Materials with the potential to become dosimeters are of interest in radiation physics. In this research, the materials were analyzed and compared in relation to their linearity ranges. Samples of ethylene vinyl-acetate copolymer (EVA) were irradiated with doses from 10 Gy to 10 kGy using a 60Co Gamma-Cell system 220 and evaluated with the FTIR technique. The linearity analyses were applied through two methodologies, searching for linear regions in their response. The results show that both applied analyses indicate linear regions in defined dose interval. The radiation detectors EVA can be useful for radiation dosimetry in intermediate and high doses.

  5. 21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate copolymers. 177.1350 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate copolymers may be safely used as articles or components of articles...

  6. Novel antibacterial mouthguard material manufactured using silver-nanoparticleembedded ethylene-vinyl acetate copolymer masterbatch.

    PubMed

    Yoshida, Yuriko; Churei, Hiroshi; Takeuchi, Yasuo; Wada, Takahiro; Uo, Motohiro; Izumi, Yuichi; Ueno, Toshiaki

    2018-01-26

    The purpose of the present study was to develop an antibacterial mouthguard (MG) material using a masterbatch of silvernanoparticle-embedded ethylene-vinyl acetate (EVA) copolymers. In order to verify that the testing material was clinically applicable as an antibacterial MG material, we conducted an antibacterial test, a shock absorption test, and analysis of in vitro silver release. The colony-forming activity of Streptococcus sobrinus, Porphyromonas gingivalis, and Escherichia coli were significantly inhibited on the testing materials compared with the commercial EVA sheet (p<0.05). The shock absorption capability of the testing material was not significantly different from that of the commercial EVA sheet. Cumulative silver release (in pure water) from the testing materials were infinitesimal after soaking for 20 days, which implied that there could be no harm in wearing the MG during exercise. These results showed that this testing material could be clinically applicable as an antibacterial MG material.

  7. Development of Damp-Heat Resistant Self-Primed EVA and Non-EVA Encapsulant Formulations at NREL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F. J.; Jorgensen, G. J.

    2005-11-01

    Self-primed ethylene-vinyl acetate (EVA) and non-EVA (PMG) encapsulant formulations were developed that have greater resistance to damp heat exposure at 85 deg C and 85% relative humidity (RH) (in terms of adhesion strength to glass substrates) than a commonly used commercial EVA product. The self-primed EVA formulations were developed on the basis of high-performing glass priming formulations that have previously proven to significantly enhance the adhesion strength of unprimed and primed EVA films on glass substrates during damp heat exposure. The PMG encapsulant formulations were based on an ethylene-methylacrylate copolymer containing glycidyl methacrylate.

  8. 21 CFR 177.1360 - Ethylene-vinyl acetate-vinyl alcohol copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate-vinyl alcohol copolymers... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1360 Ethylene-vinyl acetate-vinyl alcohol copolymers. Ethylene-vinyl acetate-vinyl alcohol copolymers (CAS Reg. No. 26221-27-2...

  9. Property tuning of poly(lactic acid)/cellulose bio-composites through blending with modified ethylene-vinyl acetate copolymer.

    PubMed

    Pracella, Mariano; Haque, Md Minhaz-Ul; Paci, Massimo; Alvarez, Vera

    2016-02-10

    The effect of addition of an ethylene-vinyl acetate copolymer modified with glycidyl methacrylate (EVA-GMA) on the structure and properties of poly(lactic acid) (PLA) composites with cellulose micro fibres (CF) was investigated. Binary (PLA/CF) and ternary (PLA/EVA-GMA/CF) composites obtained by melt mixing in Brabender mixer were analysed by SEM, POM, WAXS, DSC, TGA and tensile tests. The miscibility and morphology of PLA/EVA-GMA blends were first examined as a function of composition: a large rise of PLA spherulite growth rate in the blends was discovered with increasing the EVA-GMA content (0-30 wt%) in the isothermal crystallization both from the melt and the solid state. PLA/EVA-GMA/CF ternary composites displayed improved adhesion and dispersion of fibres into the matrix as compared to PLA/CF system. Marked changes of thermodynamic and tensile parameters, as elastic modulus, strength and elongation at break were observed for the composites, depending on blend composition, polymer miscibility and fibre-matrix chemical interactions at the interface. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Ethylene vinyl acetate (EVA) as a new drug carrier for 3D printed medical drug delivery devices.

    PubMed

    Genina, Natalja; Holländer, Jenny; Jukarainen, Harri; Mäkilä, Ermei; Salonen, Jarno; Sandler, Niklas

    2016-07-30

    The main purpose of this work was to investigate the printability of different grades of ethylene vinyl acetate (EVA) copolymers as new feedstock material for fused-deposition modeling (FDM™)-based 3D printing technology in fabrication of custom-made T-shaped intrauterine systems (IUS) and subcutaneous rods (SR). The goal was to select an EVA grade with optimal properties, namely vinyl acetate content, melting index, flexural modulus, for 3D printing of implantable prototypes with the drug incorporated within the entire matrix of the medical devices. Indomethacin was used as a model drug in this study. Out of the twelve tested grades of the EVA five were printable. One of them showed superior print quality and was further investigated by printing drug-loaded filaments, containing 5% and 15% indomethacin. The feedstock filaments were fabricated by hot-melt extrusion (HME) below the melting point of the drug substance and the IUS and SR were successfully printed at the temperature above the melting point of the drug. As a result, the drug substance in the printed prototypes showed to be at least partly amorphous, while the drug in the corresponding HME filaments was crystalline. This difference affected the drug release profiles from the filaments and printed prototype products: faster release from the prototypes over 30days in the in vitro tests. To conclude, this study indicates that certain grades of EVA were applicable feedstock material for 3D printing to produce drug-loaded implantable prototypes. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Multidimensional chromatographic techniques for hydrophilic copolymers II. Analysis of poly(ethylene glycol)-poly(vinyl acetate) graft copolymers.

    PubMed

    Knecht, Daniela; Rittig, Frank; Lange, Ronald F M; Pasch, Harald

    2006-10-13

    A large variety of hydrophilic copolymers is applied in different fields of chemical industry including bio, pharma and pharmaceutical applications. For example, poly(ethylene glycol)-poly(vinyl alcohol) graft copolymers that are used as tablet coatings are responsible for the controlled release of the active compounds. These copolymers are produced by grafting of vinyl acetate onto polyethylene glycol (PEG) and subsequent hydrolysis of the poly(ethylene glycol)-poly(vinyl acetate) graft copolymers. The poly(ethylene glycol)-poly(vinyl acetate) copolymers are distributed with regard to molar mass and chemical composition. In addition, they frequently contain the homopolymers polyethylene glycol and polyvinyl acetate. The comprehensive analysis of such complex systems requires hyphenated analytical techniques, including two-dimensional liquid chromatography and combined LC and nuclear magnetic resonance spectroscopy. The development and application of these techniques are discussed in the present paper.

  12. Determination of the linear coefficient of thermal expansion in polymer films at the nanoscale: influence of the composition of EVA copolymers and the molecular weight of PMMA.

    PubMed

    González-Benito, J; Castillo, E; Cruz-Caldito, J F

    2015-07-28

    Nanothermal-expansion of poly(ethylene-co-vinylacetate), EVA, and poly(methyl methacrylate), PMMA, in the form of films was measured to finally obtain linear coefficients of thermal expansion, CTEs. The simple deflection of a cantilever in an atomic force microscope, AFM, was used to monitor thermal expansions at the nanoscale. The influences of: (a) the structure of EVA in terms of its composition (vinylacetate content) and (b) the size of PMMA chains in terms of the molecular weight were studied. To carry out this, several polymer samples were used, EVA copolymers with different weight percents of the vinylacetate comonomer (12, 18, 25 and 40%) and PMMA polymers with different weight average molecular weights (33.9, 64.8, 75.600 and 360.0 kg mol(-1)). The dependencies of the vinyl acetate weight fraction of EVA and the molecular weight of PMMA on their corresponding CTEs were analyzed to finally explain them using new, intuitive and very simple models based on the rule of mixtures. In the case of EVA copolymers a simple equation considering the weighted contributions of each comonomer was enough to estimate the final CTE above the glass transition temperature. On the other hand, when the molecular weight dependence is considered the free volume concept was used as novelty. The expansion of PMMA, at least at the nanoscale, was well and easily described by the sum of the weighted contributions of the occupied and free volumes, respectively.

  13. Effect of electron beam irradiation and microencapsulation on the flame retardancy of ethylene-vinyl acetate copolymer materials during hot water ageing test

    NASA Astrophysics Data System (ADS)

    Sheng, Haibo; Zhang, Yan; Wang, Bibo; Yu, Bin; Shi, Yongqian; Song, Lei; Kundu, Chanchal Kumar; Tao, Youji; Jie, Ganxin; Feng, Hao; Hu, Yuan

    2017-04-01

    Microencapsulated ammonium polyphosphate (MCAPP) in combination with polyester polyurethane (TPU) was used to flame retardant ethylene-vinyl acetate copolymer (EVA). The EVA composites with different irradiation doses were immersed in hot water (80 °C) to accelerate ageing process. The microencapsulation and irradiation dose ensured positive impacts on the properties of the EVA composites in terms of better dimensional stability and flame retardant performance. The microencapsulation of APP could lower its solubility in water and the higher irradiation dose led to the more MCAPP immobilized in three dimensional crosslinked structure of the EVA matrix which could jointly enhance the flame retardant and electrical insulation properties of the EVA composites. So, the EVA composites with 180 kGy irradiation dose exhibited better dimensional stability than the EVA composites with 120 kGy due to the higher crosslinking degree. Moreover, the higher irradiation dose lead to the more MCAPP immobilizated in crosslinked three-dimensional structure of EVA, enhancing the flame retardancy and electrical insulation properties of the EVA composites. After ageing test in hot water at 80 °C for 2 weeks, the EVA/TPU/MCAPP composite with 180 kGy could still maintain the UL-94 V-0 rating and the limiting oxygen index (LOI) value was as high as 30%. This investigation indicated the flame retardant EVA cable containing MCAPP could achieve stable properties and lower electrical fire hazard risk during long-term hot water ageing test.

  14. Morphological and Mechanical Properties of Polypropylene[PP]/Poly(Ethylene Vinyl Acetate)[EVA] Blends. I. Homopolymer PP/Eva Systems

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ramirez-Vargas, E.

    2000-10-01

    Morphological and mechanical properties of polypropylene [PP]/poly(ethylene vinyl acetate) [EVA] blends have been studied. Infrared results using thin films first indicated a transition toward compatibility between both components at concentrations above 40% EVA. The transition was verified with different experimental techniques and it was associated to morphological changes and mechanical properties. The PP/EVA blends were mechanically evaluated in terms of impact and tensile strength to determine the influence of blending on the performance properties of these materials. Agreement was found between the transition and the enhancement of both elongation at break and impact strength.

  15. New monitoring by thermogravimetry for radiation degradation of EVA

    NASA Astrophysics Data System (ADS)

    Boguski, J.; Przybytniak, G.; Łyczko, K.

    2014-07-01

    The radiation ageing of ethylene vinyl-acetate copolymer (EVA) as the jacket of cable applied in nuclear power plant was carried out by gamma rays irradiation, and the degradation was monitored by a thermo-gravimetric analysis (TGA). The EVA decomposition rate in air by the isothermal at 400 °C decreased with increase of dose and also with decrease of the dose rate. The behavior of EVA jacket of cable indicated that the decomposition rate at 400 °C was reduced with increase of oxidation. The elongation at break by tensile test for the radiation aged EVA was closely related to the decomposition rate at 400 °C; therefore, the TGA might be applied for a diagnostic technique of the cable degradation.

  16. Effects of solubilizing surfactants and loading of antiviral, antimicrobial, and antifungal drugs on their release rates from ethylene vinyl acetate copolymer

    PubMed Central

    Tallury, Padmavathy; Randall, Marcus K; Thaw, Khin L; Preisser, John S.; Kalachandra, Sid

    2013-01-01

    Objectives This study investigates the effects of surfactants and drug loading on the drug release rate from ethylene vinyl acetate (EVA) copolymer. The release rate of nystatin from EVA was studied with addition of non-ionic surfactants Tween 60 and Cremophor RH 40. In addition, the effect of increasing drug load on the release rates of nystatin, chlorhexidine diacetate and acyclovir is also presented. Method Polymer casting solutions were prepared by stirring EVA copolymer and nystatin (2.5 wt %) in dichloromethane. Nystatin and surfactants were added in ratios of (1:1), (1:2) and (1:3). Drug loading was studied with 2.5, 5.0, 7.5, and 10.0% wt. proportions of nystatin, chlorhexidine diacetate and acyclovir incorporated into a separate polymer. Three drug loaded polymer square films (3cm × 3cm × 0.08 cm) were cut from dry films to follow the kinetics of drug release at 37°C. 10 ml of either distilled water or PBS was used as the extracting medium that was replaced daily. PBS was used for nystatin release with addition of surfactants and water was used for the study on drug loading and surfactant release. The rate of drug release was measured by UV-spectrophotometer. The amount of surfactant released was determined by HPLC. Results The release of nystatin was low in PBS and its release rate increased with the addition of surfactants. Also, increasing surfactant concentrations resulted in increased drug release rates. The release rates of chlorhexidine diacetate (p<0.0001), acyclovir (p<0.0003) and nystatin (p<0.0017) linearly increased with increasing drug loads. The amount of surfactants released was above the CMC. Significance This study demonstrates that the three therapeutic agents show a sustained rate of drug release from EVA copolymer over extended periods of time. Nystatin release in PBS is low owing to its poor solubility. Its release rate is enhanced by addition of surfactants and increasing the drug load as well. PMID:17049593

  17. Adhesion Strength Study of EVA Encapsulants on Glass Substrates

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F. J.; Glick, S. H.

    2003-05-01

    An extensive peel-test study was conducted to investigate the various factors that may affect the adhesion strength of photovoltaic module encapsulants, primarily ethylene-vinyl acetate (EVA), on glass substrates of various laminates based on a common configuration of glass/encapsulant/backfoil. The results show that"pure" or"absolute" adhesion strength of EVA-to-glass was very difficult to obtain because of tensile deformation of the soft, semi-elastic EVA layer upon pulling. A mechanically"strong enough" backing foil on the EVA was critical to achieving the"apparent" adhesion strength. Peel test method with a 90-degree-pull yielded similar results to a 180-degree-pull. The 90-degree-pull method better revealed the four stages ofmore » delamination failure of the EVA/backfoil layers. The adhesion strength is affected by a number of factors, which include EVA type, formulation, backfoil type and manufacturing source, glass type, and surface priming treatment on the glass surface or on the backfoil. Effects of the glass-cleaning method and surface texture are not obvious. Direct priming treatments used in the work did not improve, or even worsened, the adhesion. Aging of EVA by storage over~5 years reduced notably the adhesion strength. Lower adhesion strengths were observed for the blank (unformulated) EVA and non-EVA copolymers, such as poly(ethylene-co-methacrylate) (PEMA) or poly(ethylene-co-butylacrylate) (PEBA). Their adhesion strengths increased if the copolymers were cross-linked. Transparent fluoropolymer superstrates such as TefzelTM and DureflexTM films used for thin-film PV modules showed low adhesion strengths to the EVA at a level of~2 N/mm.« less

  18. Highly filled biocomposites based on ethylene-vinyl acetate copolymer and wood flour

    NASA Astrophysics Data System (ADS)

    Shelenkov, P. G.; Pantyukhov, P. V.; Popov, A. A.

    2018-05-01

    Recently, there is a great interest in the world to biodegradable materials based on synthetic polymers in a composition with natural fillers. Highly filled polymer composite materials based on various grades of synthetic block copolymer of ethylene vinyl acetate with wood flour were under investigation. Five grades of ethylene-vinyl acetate copolymer differing in the content of vinyl acetate groups and a melt flow index were used in this work in order to find the best one for highly filled biocomposites. Wood flour content in biocomposites was 50, 60, 70 weight %. The rheological and physico-mechanical characteristics of the resulting biocomposites were studied.

  19. Effect of chain structure on hydrogen bonding in vinyl acetate - vinyl alcohol copolymers

    NASA Astrophysics Data System (ADS)

    Merekalova, Nadezhda D.; Bondarenko, Galina N.; Denisova, Yuliya I.; Krentsel, Liya B.; Litmanovich, Arkadiy D.; Kudryavtsev, Yaroslav V.

    2017-04-01

    FTIR spectroscopy and semi-empirical AM1 method are used to study hydrogen bonding in multiblock and random equimolar copolymers of vinyl acetate and vinyl alcohol. An energetically beneficial zip-holder complex, built on multiple inter- and intrachain hydroxyl-hydroxyl bonds and an intrachain hydroxyl-acetyloxy bond, can be formed between two vinyl alcohol sequences. As a result, multiblock copolymers reveal stronger degree of association that affects crystallinity, as well as various rheological and relaxation properties discussed in the literature. Macromolecular complexes in random copolymers are weak and tend to be destroyed in the presence of residual DMF solvent and adsorbed water. Nevertheless, a rather stable interchain quaternary complex can be formed that includes vinyl alcohol and vinyl acetate units and DMF and water molecules. For a single chain it is shown that an H-bond between neighboring vinyl alcohol and vinyl acetate monomer units mostly engages a carbonyl oxygen atom of the vinyl acetate, if the vinyl alcohol belongs to a short (<5 units) sequence, and an ether oxygen atom in the other case. On the whole, the quantum chemistry calculations shed much light on the origin of distinctions in the copolymer FTIR spectra, which may seem subtle when considered standalone.

  20. Acoustic Behavior of Subfloor Lightweight Mortars Containing Micronized Poly (Ethylene Vinyl Acetate) (EVA)

    PubMed Central

    Brancher, Luiza R.; Nunes, Maria Fernanda de O.; Grisa, Ana Maria C.; Pagnussat, Daniel T.; Zeni, Mára

    2016-01-01

    This paper aims to contribute to acoustical comfort in buildings by presenting a study about the polymer waste micronized poly (ethylene vinyl acetate) (EVA) to be used in mortars for impact sound insulation in subfloor systems. The evaluation method included physical, mechanical and morphological properties of the mortar developed with three distinct thicknesses designs (3, 5, and 7 cm) with replacement percentage of the natural aggregate by 10%, 25%, and 50% EVA. Microscopy analysis showed the surface deposition of cement on EVA, with preservation of polymer porosity. The compressive creep test estimated long-term deformation, where the 10% EVA sample with a 7 cm thick mortar showed the lowest percentage deformation of its height. The impact noise test was performed with 50% EVA samples, reaching an impact sound insulation of 23 dB when the uncovered slab was compared with the 7 cm thick subfloor mortar. Polymer waste addition decreased the mortar compressive strength, and EVA displayed characteristics of an influential material to intensify other features of the composite. PMID:28787851

  1. Acoustic Behavior of Subfloor Lightweight Mortars Containing Micronized Poly (Ethylene Vinyl Acetate) (EVA).

    PubMed

    Brancher, Luiza R; Nunes, Maria Fernanda de O; Grisa, Ana Maria C; Pagnussat, Daniel T; Zeni, Mára

    2016-01-15

    This paper aims to contribute to acoustical comfort in buildings by presenting a study about the polymer waste micronized poly (ethylene vinyl acetate) (EVA) to be used in mortars for impact sound insulation in subfloor systems. The evaluation method included physical, mechanical and morphological properties of the mortar developed with three distinct thicknesses designs (3, 5, and 7 cm) with replacement percentage of the natural aggregate by 10%, 25%, and 50% EVA. Microscopy analysis showed the surface deposition of cement on EVA, with preservation of polymer porosity. The compressive creep test estimated long-term deformation, where the 10% EVA sample with a 7 cm thick mortar showed the lowest percentage deformation of its height. The impact noise test was performed with 50% EVA samples, reaching an impact sound insulation of 23 dB when the uncovered slab was compared with the 7 cm thick subfloor mortar. Polymer waste addition decreased the mortar compressive strength, and EVA displayed characteristics of an influential material to intensify other features of the composite.

  2. Effect of Rare Earth Ions on the Properties of Composites Composed of Ethylene Vinyl Acetate Copolymer and Layered Double Hydroxides

    PubMed Central

    Wang, Lili; Li, Bin; Zhao, Xiaohong; Chen, Chunxia; Cao, Jingjing

    2012-01-01

    Background The study on the rare earth (RE)-doped layered double hydroxides (LDHs) has received considerable attention due to their potential applications in catalysts. However, the use of RE-doped LDHs as polymer halogen-free flame retardants was seldom investigated. Furthermore, the effect of rare earth elements on the hydrophobicity of LDHs materials and the compatibility of LDHs/polymer composite has seldom been reported. Methodology/Principal Findings The stearate sodium surface modified Ni-containing LDHs and RE-doped Ni-containing LDHs were rapidly synthesized by a coprecipitation method coupled with the microwave hydrothermal treatment. The influences of trace amounts of rare earth ions La, Ce and Nd on the amount of water molecules, the crystallinity, the morphology, the hydrophobicity of modified Ni-containing LDHs and the adsorption of modifier in the surface of LDHs were investigated by TGA, XRD, TEM, contact angle and IR, respectively. Moreover, the effects of the rare earth ions on the interfacial compatibility, the flame retardancy and the mechanical properties of ethylene vinyl acetate copolymer (EVA)/LDHs composites were also explored in detail. Conclusions/Significance S-Ni0.1MgAl-La displayed more uniform dispersion and better interfacial compatibility in EVA matrix compared with other LDHs. Furthermore, the S-Ni0.1MgAl-La/EVA composite showed the best fire retardancy and mechanical properties in all composites. PMID:22693627

  3. 21 CFR 175.350 - Vinyl acetate/crotonic acid copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Vinyl acetate/crotonic acid copolymer. 175.350 Section 175.350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADHESIVES AND COMPONENTS OF...

  4. Enhancing the thermal conductivity of ethylene-vinyl acetate (EVA) in a photovoltaic thermal collector

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Allan, J., E-mail: james.p.allan14@gmail.com; ChapmanBDSP, Saffron House, 6-10 Kirby Street, London, EC1N 8EQ; Pinder, H.

    2016-03-15

    Samples of Ethylene-Vinyl Acetate (EVA) were doped with particles of Boron Nitride (BN) in concentrations ranging from 0-60% w/w. Thermal conductivity was measured using a Differential Scanning Calorimetery (DSC) technique. The thermal conductivity of parent EVA was increased from 0.24 W/m ⋅ K to 0.80 W/m ⋅ K for the 60% w/w sample. Two PV laminates were made; one using the parent EVA the other using EVA doped with 50% BN. When exposed to a one directional heat flux the doped laminate was, on average, 6% cooler than the standard laminate. A finite difference model had good agreement with experimentalmore » results and showed that the use of 60% BN composite achieved a PV performance increase of 0.3% compared to the standard laminate.« less

  5. In situ electron microscopy of Braille microsystems: photo-actuation of ethylene vinyl acetate/carbon nanotube composites

    NASA Astrophysics Data System (ADS)

    Czaniková, Klaudia; Krupa, Igor; Račko, Dušan; Šmatko, Vasilij; Campo, Eva M.; Pavlova, Ewa; Omastová, Mária

    2015-02-01

    The development of new types of tactile displays based on the actuation of composite materials can aid the visually impaired. Micro/nano systems based on ethylene vinyl acetate (EVA) polymeric matrices enriched with multiwalled carbon nanotubes (MWCNT) can produce ensembles capable of light-induced actuation. In this report, we investigate two types of commercial EVA copolymers matrices containing 28 and 50 wt% vinyl-acetate (VA). Non-covalent modification of carbon nanotubes was achieved through a compatibilization technique that appends the pyrenenyl and cholesteryl groups on the carbon nanotubes (CNTs) surface. EVA/MWCNT nanocomposites were prepared by casting from a solution. These composites were shaped into Braille elements using molds. The deformation of the Braille element (BE) under light-emitting diode (LED) illumination was observed for the first time by in situ scanning electron microscopy (SEM). The superior actuation performance promoted by the EVA/MWCNT nanocomposites indicates that these materials will be useful in the future as light-driven micro/nano system actuators.

  6. The properties of neutron shielding and flame retardant of EVA polymer after modified by EB accelerator

    NASA Astrophysics Data System (ADS)

    Wang, Guo-hui; He, Man-li; Jiang, Dan-feng; He, Fan; Chang, Shu-quan; Dai, Yao-dong

    2017-11-01

    According to the requirements for neutron shielding and flame retardant properties of some nuclear devices, a new kind of polymer composite materials based on ethylene and vinyl acetate (EVA) polymer have been studied. EVA is the copolymer of ethylene and vinyl acetate, It can be used as materials for applications due to its flexibility, good processability, and low cost. Insulating EVA can be used for cable sheath, automotive sound damping and many other appication. Boron nitride (BN), zinc borate (ZB), magnesium hydroxide (MH) and EVA consisted the compounds with the properties of neutron shielding and flame retardant. With increasing of the contents of BN and ZB, the neutron shielding performance of materials increased up to 33.08%. With the increasing contents of MH and ZB as flame retardant, oxygen index of material have been improved. The elongation at break and tensile strength of material decreased with the increasing of filler powders. Sheet E was chosen and modified by electron beam accelerator in different doses. After modification by electron beam irradiation the sheets showed varying degrees of transformation in the OI, neutron shielding rate and mechanical properties.

  7. 21 CFR 177.1360 - Ethylene-vinyl acetate-vinyl alcohol copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Premarket Approval (HFS-200), Center for Food Safety and Applied Nutrition, Food and Drug Administration... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene-vinyl acetate-vinyl alcohol copolymers. 177.1360 Section 177.1360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN...

  8. Factors that affect the EVA encapsulant discoloration rate upon accelerated exposure

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F.J.

    1994-12-31

    Several factors that may affect the net discoloration rate of the ethylene-vinyl acetate (EVA) copolymer encapsulants used in crystalline-Si photovoltaic (c-Si PV) modules upon accelerated exposure have been investigated by employing UV-visible spectrophotometry, spectrocolorimetry, and fluorescence analysis. A number of laminated films, including the two typical EVA formulations, A9918 and 15295, were studied. The results indicate that the rate of EVA discoloration is affected by the (1) curing agent and curing conditions; (2) presence and concentration of curing-generated, UV-excitable chromophores; (3) UV light intensity; (4) loss rate of the UV absorber, Cyasorb UV 531; (5) lamination; (6) film thickness; andmore » (7) photobleaching rate due to the diffusion of air into the laminated films. In general, the loss rate of the UV absorber and the rate of discoloration from light yellow to brown follow a sigmoidal pattern. A reasonable correlation for net changes in transmittance at 420 nm, yellowness index, and fluorescence peak area (or intensity) ratio is obtained as the extent of EVA discoloration progressed.« less

  9. Thermal and chemical stabilization of ethylene/vinyl acetate/vinyl alcohol (EVA-OH) terpolymers under nitroplasticizer environments

    DOE PAGES

    Yang, Dali; Hubbard, Kevin M.; Henderson, Kevin C.; ...

    2014-09-17

    Here, we compare the aging behaviors of cross-linked ethylene/vinyl acetate/vinyl alcohol terpolymers, also referred to as EVA-OH, when they are either immersed in nitroplasticizer (NP) liquid or exposed to NP vapor at different temperatures. And while thermogravimetric analysis and differential scanning calorimetry are used to probe the thermal stability of aged NP and polymers, Fourier transform infrared, gel permeation chromatography, ultra-violet/vis, and nuclear magnetic resonance are used to probe their structural changes over the aging process. Our study confirms that NP degrades through C[BOND]N cleavage, and releases HONO molecules at a slightly elevated temperature (<75°C). As these molecules accumulate inmore » the vapor phase, they react among themselves to create an acidic environment. Therefore, these chemical constituents in the NP vapor significantly accelerate the hydrolysis of EVA-OH polymer. When the hydrolysis occurs in both vinyl acetate and urethane groups and the scission at the cross-linker progresses, EVA-OH becomes vulnerable to further degradation in the NP vapor environment. Finally, through the comprehensive characterization, the possible degradation mechanisms of the terpolymers are proposed.« less

  10. Thermoplastic rubber comprising ethylene-vinyl acetate copolymer, asphalt and fluxing oil

    NASA Technical Reports Server (NTRS)

    Hendel, F. J. (Inventor)

    1970-01-01

    A thermoplastic rubber is made from a mixture of between about 10 percent and about 50 percent of asphalt, between about 5 percent and about 30 percent fluxing oil, and between about 35 percent and about 70 percent of a copolymer of polyethylene and vinyl acetate.

  11. Incorporation of nisin in poly (ethylene-co-vinyl acetate) films by melt processing: a study on the antimicrobial properties.

    PubMed

    Scaffaro, Roberto; Botta, Luigi; Marineo, Sandra; Puglia, Anna Maria

    2011-07-01

    Both industry and academia have shown a growing interest in materials with antimicrobial properties suitable for food packaging applications. In this study, we prepared and characterized thin films of ethylene-co-vinyl acetate (EVA) copolymer with antimicrobial properties. The films were prepared with a film blowing process by incorporating a nisin preparation as an antimicrobial agent in the melt. Two grades of EVA containing 14 and 28% (wt/wt) vinyl acetate (EVA 14 and EVA 28, respectively) and two commercial formulations of nisin with different nominal activities were used. The effect of the nisin concentration also was evaluated. The films with the highest antimicrobial activity were those formulated with nisin at the highest activity and EVA with the highest content of vinyl acetate. The use of the commercial formulation of nisin with high activity in the EVA films allowed reduction in the amount of nisin needed to provide antimicrobial properties. Consequently, the mechanical properties of these films were only slightly inferior to those of the pure polymers. In contrast, films prepared by incorporating more of the nisin with lower activity had poor mechanical properties. The effect of different processing temperatures used in the preparation of the films on the antimicrobial properties of the films also was evaluated. The materials displayed antimicrobial properties even when they were prepared at temperatures as high as 160 °C, probably because of the very short processing time (60 to 90 s) required for preparation. Copyright ©, International Association for Food Protection

  12. Effect of PEG6000 on the in vitro and in vivo transdermal permeation of ondansetron hydrochloride from EVA1802 membranes.

    PubMed

    Krishnaiah, Yellela S R; Rama, Bukka; Raghumurthy, Vanambattina; Ramanamurthy, Kolapalli V; Satyanarayana, Vemulapalli

    2009-01-01

    The objective was to evaluate ethylene vinyl acetate (EVA) copolymer membranes with vinyl acetate content of 18% w/w (EVA1802) for transdermal delivery of ondansetron hydrochloride. The EVA1802 membranes containing selected concentrations (0, 5, 10 and 15% w/w) of PEG6000 were prepared, and subjected to in vitro permeation studies from a nerodilol-based drug reservoir. Flux of ondansetron from EVA1802 membranes without PEG6000 was 64.1 +/- 0.6 microg/cm(2.)h, and with 10%w/w of PEG6000 (EVA1802-PEG6000-10) it increased to 194.9 +/- 4.6 microg/cm(2.)h. However, with 15%w/w of PEG6000, EVA1802 membranes produced a burst release of drug which in turn decreased drug flux. The EVA1802-PEG6000-10 membrane was coated with an adhesive emulsion, applied to rat epidermis and subjected to in vitro permeation studies against controls. Flux of ondansetron from transdermal patch across rat epidermis was 111.7 +/- 1.3 microg/cm(2.)h, which is about 1.3 times the required flux. A TTS was fabricated using adhesive-coated EVA1802-PEG6000-10 membrane and other TTS components, and subjected to in vivo delivery in human volunteers against a control. It was concluded from the comparative pharmacokinetic study that TTS of ondansetron, prepared with EVA1802-PEG6000-10 membrane, provided average steady-state plasma concentration on par with multiple-dosed oral tablets, but with a low percent of peak-to-trough fluctuation.

  13. Radiation resistance of acetal copolymers (in German)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wolters, E.; Roesinger, S.

    1973-01-01

    For the radiation sterilization of equipment and containers made from plastic material, a dose of 2.5 x 10/sup 4/ J/kg (2.5 Mrad) is normally used. Experiments are described which show the influence of the sterilization doses applied in practice on the physical properties of the acetal copolymer Hostaform. Although a certain destruction and simultaneously a reduction in viscous properties are observed as a result of irradiations with gamma rays up to 2.5 x 10/sup 4/ J/kg, the tensile strength remains practically unchanged. Hence gamma -ray sterilization can be applied if there are no special requirements as to the mechanical propertiesmore » of the sterile equipment. (GE)« less

  14. Effect of VA and MWNT contents on the rheological and physical properties of EVA

    NASA Astrophysics Data System (ADS)

    Kim, Jong-Ho; Lee, Seungwon; Kim, Byoung Chul; Shin, Bong-Seob; Jeon, Jong-Young; Chae, Dong Wook

    2016-02-01

    Ethylene vinyl acetate (EVA) copolymers with two different VA contents (15 and 33 wt.%, denoted by EVA15 and EVA33, respectively) were melt compounded with multi-walled carbon nanotubes (MWNTs) and the effect of VA and nanotube contents on the rheological, thermal and morphological properties was investigated. The addition of nanotubes into both EVAs increased the onset temperature of crystallization and broadened the peak, but further addition from 3 wt.% slightly decreased the temperature with increasing nanotube contents. In the wide angle X-ray diffraction patterns the peak of EVA15 was little affected by the presence of nanotubes but that of EVA33 slightly shifted to higher degree and became sharper with increasing nanotube contents. Dynamic viscosity (η') increased with nanotube contents giving abrupt increase at 2 wt.% nanotubes. Loss tangent decreased with increasing nanotube contents exhibiting the plateau-like behavior over most of the frequency range from 2 wt.% nanotubes. In the Casson plot, yield stress increased with nanotube content and its increasing extent was more notable for more VA content. In the Cole-Cole plot, the presence of nanotubes from 2 wt.% gave rise to the deviation from the single master curve by decreasing the slope. The deviated extent of EVA33 became more remarkable with increasing nanotube contents than that of EVA15. The stress-strain curve showed that more improved tensile modulus and yield stress were achieved by the introduction of MWNTs for EVA 33 than for EVA15. Tensile strength of EVA33 increased with increasing nanotube contents, while that of EVA15 decreased.

  15. Electron beam irradiation induced compatibilization of immiscible polyethylene/ethylene vinyl acetate (PE/EVA) blends: Mechanical properties and morphology stability

    NASA Astrophysics Data System (ADS)

    Entezam, Mehdi; Aghjeh, Mir Karim Razavi; Ghaffari, Mehdi

    2017-02-01

    Gel content, mechanical properties and morphology of immiscible PE/EVA blends irradiated by high energy electron beam were studied. The results of gel content measurements showed that the capability of cross-linking of the blend samples increased with an increase of the EVA composition. Also, the gel content for most compositions of the blends displayed a positive deviation from the additive rule. The results of mechanical properties showed that the tensile strength and elongation at break of the samples increased and decreased, respectively, with irradiation dose. On the other hand, the mechanical properties of the irradiated blends also depicted a positive deviation from additive rule contrary to the un-irradiated blends. A synergistic effect observed for the mechanical properties improvement of the irradiated blends and it was attributed to the probable formation of the PE-graft-EVA copolymers at the interface of the blends during the irradiation process. A theoretical analysis revealed that irradiation induced synergistic effect was more significant for EVA-rich blends with weaker interfacial interaction as compared to PE-rich blends. The morphological analysis indicated that the blend morphology was not affected obviously, whereas it was stabilized by irradiation.

  16. Polyblends of LDPE with EVA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Deanin, R.D.; Hou, T.J.A.

    1993-12-31

    Melt processability of LDPE was improved by blending with EVA copolymers containing 10-28% VA. Softening of modules was controlled primarily by overall VA content of the blends. Tensile necking was converted to smooth rubbery elongation by adding larger amounts of VA. Transparency was produced by adding EVA containing 10% VA and then stretching the polyblend film. These parameters give the film manufacturer wide control over processability and properties.

  17. [Prediction of Encapsulation Temperatures of Copolymer Films in Photovoltaic Cells Using Hyperspectral Imaging Techniques and Chemometrics].

    PubMed

    Lin, Ping; Chen, Yong-ming; Yao, Zhi-lei

    2015-11-01

    A novel method of combination of the chemometrics and the hyperspectral imaging techniques was presented to detect the temperatures of Ethylene-Vinyl Acetate copolymer (EVA) films in photovoltaic cells during the thermal encapsulation process. Four varieties of the EVA films which had been heated at the temperatures of 128, 132, 142 and 148 °C during the photovoltaic cells production process were used for investigation in this paper. These copolymer encapsulation films were firstly scanned by the hyperspectral imaging equipment (Spectral Imaging Ltd. Oulu, Finland). The scanning band range of hyperspectral equipemnt was set between 904.58 and 1700.01 nm. The hyperspectral dataset of copolymer films was randomly divided into two parts for the training and test purpose. Each type of the training set and test set contained 90 and 10 instances, respectively. The obtained hyperspectral images of EVA films were dealt with by using the ENVI (Exelis Visual Information Solutions, USA) software. The size of region of interest (ROI) of each obtained hyperspectral image of EVA film was set as 150 x 150 pixels. The average of reflectance hyper spectra of all the pixels in the ROI was used as the characteristic curve to represent the instance. There kinds of chemometrics methods including partial least squares regression (PLSR), multi-class support vector machine (SVM) and large margin nearest neighbor (LMNN) were used to correlate the characteristic hyper spectra with the encapsulation temperatures of of copolymer films. The plot of weighted regression coefficients illustrated that both bands of short- and long-wave near infrared hyperspectral data contributed to enhancing the prediction accuracy of the forecast model. Because the attained reflectance hyperspectral data of EVA materials displayed the strong nonlinearity, the prediction performance of linear modeling method of PLSR declined and the prediction precision only reached to 95%. The kernel-based forecast models were

  18. High-temperature two-dimensional liquid chromatography of ethylene-vinylacetate copolymers.

    PubMed

    Ginzburg, Anton; Macko, Tibor; Dolle, Volker; Brüll, Robert

    2010-10-29

    Temperature rising elution fractionation hyphenated to size exclusion chromatography (TREF×SEC) is a routine technique to determine the chemical heterogeneity of semicrystalline olefin copolymers. Its applicability is limited to well crystallizing samples. High-temperature two-dimensional liquid chromatography, HT 2D-LC, where the chromatographic separation by HPLC is hyphenated to SEC (HPLC×SEC) holds the promise to separate such materials irrespective of their crystallizability. A model blend consisting of ethylene-vinyl acetate (EVA) copolymers covering a broad range of chemical composition distribution including amorphous and semicrystalline copolymers and a polyethylene standard was separated by HT 2D-LC at 140°C. Both axes of the contour plot, i.e. the compositional axis from the HPLC and the molar mass axis from the SEC separation were calibrated for the first time. Therefore, a new approach to determine the void and dwell volume of the developed HT 2D-LC instrument was applied. The results from the HT 2D-LC separation are compared to those from a cross-fractionation (TREF×SEC) experiment. Copyright © 2010. Published by Elsevier B.V.

  19. Preparation, Characterization and Thermo-Chromic Properties of EVA/VO₂ Laminate Films for Smart Window Applications and Energy Efficiency in Building.

    PubMed

    Srirodpai, Onruthai; Wootthikanokkhan, Jatuphorn; Nawalertpanya, Saiwan; Yuwawech, Kitti; Meeyoo, Vissanu

    2017-01-11

    Thermochromic films based on vanadium dioxide (VO₂)/ethylene vinyl acetate copolymer (EVA) composite were developed. The monoclinic VO₂ particles was firstly prepared via hydrothermal and calcination processes. The effects of hydrothermal time and tungsten doping agent on crystal structure and morphology of the calcined metal oxides were reported. After that, 1 wt % of the prepared VO₂ powder was mixed with EVA compound, using two different mixing processes. It was found that mechanical properties of the EVA/VO₂ films prepared by the melt process were superior to those of which prepared by the solution process. On the other hand, percentage visible light transmittance of the solution casted EVA/VO₂ film was greater than that of the melt processed composite film. This was related to the different gel content of EVA rubber and state of dispersion and distribution of VO₂ within the polymer matrix phase. Thermochromic behaviors and heat reflectance of the EVA/VO₂ film were also verified. In overall, this study demonstrated that it was possible to develop a thermochromic film using the polymer composite approach. In this regard, the mixing condition was found to be one of the most important factors affecting morphology and thermo-mechanical properties of the films.

  20. Impact property enhancement of poly (lactic acid) with different flexible copolymers

    NASA Astrophysics Data System (ADS)

    Likittanaprasong, N.; Seadan, M.; Suttiruengwong, S.

    2015-07-01

    The objective of this work was to improve the impact property of Poly (lactic acid) (PLA) by blending with different copolymers. Six flexible copolymers, namely, acrylonitrile butadiene styrene (ABS) powder, Biomax, polybutyrate adipate co-terephthalate (PBAT), polyether block amide (PEBAX), ethylene-vinyl acetate (EVA) and ethylene acrylic elastomer (EAE), with loading less than 20wt% were used and compared. The rheological, mechanical and morphological properties of samples were investigated by melt flow index, tensile testing, impact testing and scanning electron microscope (SEM), respectively. It was found that PLA added 20wt% EAE showed the highest impact strength (59.5 kJ/m2), which was 22 times higher than neat PLA. The elongation at break was also increased by 12 folds compared to neat PLA. The SEM images showed good interface and distribution for PLA containing 20wt% EAE, 15 phr Biomax and 20 wt% PEBAX.

  1. Preparation, Characterization and Thermo-Chromic Properties of EVA/VO2 Laminate Films for Smart Window Applications and Energy Efficiency in Building

    PubMed Central

    Srirodpai, Onruthai; Wootthikanokkhan, Jatuphorn; Nawalertpanya, Saiwan; Yuwawech, Kitti; Meeyoo, Vissanu

    2017-01-01

    Thermochromic films based on vanadium dioxide (VO2)/ethylene vinyl acetate copolymer (EVA) composite were developed. The monoclinic VO2 particles was firstly prepared via hydrothermal and calcination processes. The effects of hydrothermal time and tungsten doping agent on crystal structure and morphology of the calcined metal oxides were reported. After that, 1 wt % of the prepared VO2 powder was mixed with EVA compound, using two different mixing processes. It was found that mechanical properties of the EVA/VO2 films prepared by the melt process were superior to those of which prepared by the solution process. On the other hand, percentage visible light transmittance of the solution casted EVA/VO2 film was greater than that of the melt processed composite film. This was related to the different gel content of EVA rubber and state of dispersion and distribution of VO2 within the polymer matrix phase. Thermochromic behaviors and heat reflectance of the EVA/VO2 film were also verified. In overall, this study demonstrated that it was possible to develop a thermochromic film using the polymer composite approach. In this regard, the mixing condition was found to be one of the most important factors affecting morphology and thermo-mechanical properties of the films. PMID:28772413

  2. Study of montmorillonite nanoparticles and electron beam irradiation interaction of ethylene vinyl acetate (EVA)/de-vulcanized waste rubber thermoplastic composites

    NASA Astrophysics Data System (ADS)

    Bee, Soo-Tueen; Sin, Lee Tin; Hoe, Tie Teck; Ratnam, C. T.; Bee, Soo Ling; Rahmat, A. R.

    2018-05-01

    The purpose of this work was to investigate the effects of montmorillonite (MMT) loading level and electron beam irradiation on the physical-mechanical properties and thermal stability of ethylene vinyl acetate (EVA)- devulcanised waste rubber blends. The addition of MMT particles has significantly increased the d-spacing and interchain separation of deflection peak (0 0 2) of MMT particles. This indicates that MMT particles have effectively intercalated in polymer matrix of EVA-devulcanised waste rubber blends. Besides, the application of electron beam irradiation dosages <150 kGy could also significantly induce the effective intercalation effect of MMT particles in polymer matrix by introducing crosslinking networks. The increasing of electron beam irradiation dosages up to 250 kGy has gradually increased the gel content of all EVA-devulcanized rubber blends by inducing the formation of crosslinking networks in polymer matrix. Also, the tensile strength of all EVA-devulcanized waste rubber blends was gradually increased when irradiated up to 150 kGy. This is due to the occurrence of crosslinking networks by irradiation could significantly provide reinforcement effect to polymer matrix by effectively transferring the stress applied on polymer matrix throughout the whole polymer matrix.

  3. Effect of EVA on thermal stability, flammability, mechanical properties of HDPE/EVA/Mg(OH)2 composites

    NASA Astrophysics Data System (ADS)

    Cao, R.; Deng, Z. L.; Ma, Y. H.; Chen, X. L.

    2017-06-01

    In this work, ethylene vinyl acetate (EVA) is introduced to improve the properties of high-density polyethylene (HDPE)/magnesium hydroxide (MH) composites. The thermal stability, flame retardancy and mechanical properties of HDPE/EVA/MH composites are investigated and discussed. With increasing content of EVA, the limiting oxygen index (LOI) of the composites increases. The thermal stability analysis shows that the initial decomposition temperature begins at a low temperature; however, the residues of the composites at 600°C increase when HDPE is replaced by small amounts of EVA. The early degradation absorbs heat, dilute oxygen and residue. During this process, it protects the matrix inside. Compared with the HDPE/MH and EVA/MH composites, the ternary HDPE/EVA/MH composites exhibit better flame retardancy by increasing the LOI values, and reducing the heat release rate (HRR) and total heat release (THR). With increasing content of EVA, the mechanical properties can also be improved, which is attributed to the good affinity between EVA and MH particles.

  4. Influences of modified bacterial cellulose nanofibers (BCNs) on structural, thermophysical, optical, and barrier properties of poly ethylene-co-vinyl acetate (EVA) nanocomposite.

    PubMed

    Ghadikolaei, Shila Shirdel; Omrani, Abdollah; Ehsani, Morteza

    2018-04-14

    The BCNs were chemically modified using acetic anhydride with the aim of improving its dispersion and interfacial adhesion. Acetylation of BCNs was confirmed by FT-IR spectroscopy. Morphology studies using TEM and SEM revealed that a reasonable dispersion of the modified BCNs in the EVA matrix was accomplished. The DSC data displayed a little shift in the T g to higher temperatures with the incorporation of both modified and unmodified BCNs. Increased thermal stability of the nanocomposites consisting acetylated BCNs was confirmed by TGA technique. DMA measurements highlighted that the storage modulus increased and the damping properties decreased for the nanocomposites with regard to the neat EVA. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Advanced development of non-discoloring EVA-based PV encapsulants

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holley, W.H.; Galica, J.P.; Argo, S.C.

    1996-01-01

    The purpose of this investigation was to better define the problem of field yellowing of EVA-based PV encapsulant, through laboratory study of probable chemical mechanisms and the development of stabilization strategies for protecting EVA from discoloration. EVA from fielded modules was analyzed for vinyl acetate content, unsaturation, and additive levels. These test results were then compared to results from Xenon Arc Weather-Ometer aged glass/EVA/glass laminates made in the laboratory. Variables evaluated in Weather-Ometer aged laminates included ``standard-cure`` A9918P EVA, ``fast-cure`` 15295P EVA, low iron glass superstrate containing cerium oxide, and systematic elimination or addition of specific additives. Six significant findingsmore » were revealed: 1) Improved ``standard-cure`` and ``fast-cure`` type EVA encapsulants, formulations X9903P and X15303P, respectively, showed little or no yellowing after extended Weather-Ometer exposure; 2) The use of {open_quote}{open_quote}fast-cure{close_quote}{close_quote} EVA reduced discoloration when compared with {open_quote}{open_quote}standard-cure{close_quote}{close_quote} A9918P EVA; 3) Glass superstrate containing cerium oxide resulted in a reduced rate of EVA discoloration; 4) {open_quote}{open_quote}Fast-cure{close_quote}{close_quote} EVA used with glass superstrate containing cerium oxide showed no visible yellowing after 32 weeks in the Weather-Ometer{emdash}a period estimated to be roughly equivalent to 20{endash}30 years of exposure in the Southwest; 5) Severely discolored EVA samples from the field showed no measurable loss of acetate group and little detectable unsaturation; and 6) EVA encapsulant with a Tefzel cover exhibited no yellowing after extended Weather-Ometer exposure. {copyright} {ital 1996 American Institute of Physics.}« less

  6. Modeling and Prediction of Drug Dispersability in Polyvinylpyrrolidone-Vinyl Acetate Copolymer Using a Molecular Descriptor.

    PubMed

    DeBoyace, Kevin; Buckner, Ira S; Gong, Yuchuan; Ju, Tzu-Chi Rob; Wildfong, Peter L D

    2018-01-01

    The expansion of a novel in silico model for the prediction of the dispersability of 18 model compounds with polyvinylpyrrolidone-vinyl acetate copolymer is described. The molecular descriptor R3m (atomic mass weighted 3rd-order autocorrelation index) is shown to be predictive of the formation of amorphous solid dispersions at 2 drug loadings (15% and 75% w/w) using 2 preparation methods (melt quenching and solvent evaporation using a rotary evaporator). Cosolidified samples were characterized using a suite of analytical techniques, which included differential scanning calorimetry, powder X-ray diffraction, pair distribution function analysis, polarized light microscopy, and hot stage microscopy. Logistic regression was applied, where appropriate, to model the success and failure of compound dispersability in polyvinylpyrrolidone-vinyl acetate copolymer. R3m had combined prediction accuracy greater than 90% for tested samples. The usefulness of this descriptor appears to be associated with the presence of heavy atoms in the molecular structure of the active pharmaceutical ingredient, and their location with respect to the geometric center of the molecule. Given the higher electronegativity and atomic volume of these types of atoms, it is hypothesized that they may impact the molecular mobility of the active pharmaceutical ingredient, or increase the likelihood of forming nonbonding interactions with the carrier polymer. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  7. Effect of fibre treatments on tensile properties of ethylene vinyl acetate/natural rubber/mengkuang leaf fibre (EVA/NR/MLF) thermoplastic elastomer composites

    NASA Astrophysics Data System (ADS)

    Hashim, Faiezah; Ismail, Hanafi; Rusli, Arjulizan

    2017-07-01

    Nowadays, a great attention has been dedicated to natural fibers as reinforcement for polymer composites. Natural fibers, compared to glass fibers, exhibit better mechanical properties, such as stiffness, impact strength, flexibility and modulus. However, certain drawbacks, such as the incompatibility between fibers and polymer matrices, the tendency to form aggregates during processing and the poor resistance to moisture, reduce the use of these natural fibers as reinforcements in polymers. Several treatments and modifications are being used to improve the adhesion between fibre and matrix. In this work, the effect of bleaching treatments using hydrogen peroxide in the Mengkuang leaf fibre (MLF) was evaluated on tensile properties of Ethylene Vinyl Acetate (EVA)/Natural Rubber (NR)/MLF composites. Treated MLF were mixed with the EVA/NR blend in Haake internal mixer at 120 °C and rotor speed of 50 rpm for 10 minutes. Fibre morphology and the fibre/matrix interface ware further characterized by scanning electron microscopy (SEM). The tensile strength was increased by about 8% as compared to the composites with untreated fibers. The increased adhesion between fiber and matrix was also observed by SEM. Thus, EVA/NR/MLF composites reinforced with the treated fibres exhibited better tensile properties than untreated EVA/NR/MLF composites.

  8. Ethylene-Vinyl Acetate Potential Problems for Photovoltaic Packaging

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kempe, M. D.; Jorgensen, G. J.; Terwilliger, K. M.

    2006-01-01

    Photovoltaic (PV) devices are typically encapsulated using ethylene-vinyl acetate (EVA) to provide mechanical support, optical coupling, electrical isolation, and protection against environmental exposure. Under exposure to atmospheric water and/or ultraviolet radiation, EVA will decompose to produce acetic acid, lowering the pH and increasing the surface corrosion rates of embedded devices. Even though acetic acid is produced at a very slow rate, it may not take much to catalyze reactions that lead to rapid module deterioration. Another consideration is that the glass transition of EVA, as measured using dynamic mechanical analysis, begins at temperatures of about -15 degC. Temperatures lower thanmore » this can be reached for extended periods of time in some climates. Because of increased moduli below the glass transition temperature, a module may be more vulnerable to damage if a mechanical load is applied by snow or wind at low temperatures. Modules using EVA should not be rated for use at such low temperatures without additional low-temperature mechanical testing beyond the scope of UL1703.« less

  9. Guiding principle for crystalline Si photovoltaic modules with high tolerance to acetic acid

    NASA Astrophysics Data System (ADS)

    Masuda, Atsushi; Hara, Yukiko

    2018-04-01

    A guiding principle for highly reliable crystalline Si photovoltaic modules, especially those with high tolerance to acetic acid generated by hydrolysis reaction between water vapor and an ethylene-vinyl acetate (EVA) encapsulant, is proposed. Degradation behavior evaluated by the damp heat test strongly depends on Ag finger electrodes and also EVA encapsulants. The acetic acid concentration in EVA on the glass side directly determines the degradation behavior. The most important factor for high tolerance is the type of Ag finger electrode materials when using an EVA encapsulant. Photovoltaic modules using newly developed crystalline Si cells with improved Ag finger electrode materials keep their maximum power of 80% of the initial value even after the damp heat test at 85 °C and 85% relative humidity for 10000 h. The pattern of dark regions in electroluminescence images is also discussed on the basis of the dynamics of acetic acid in the modules.

  10. One-Step Preparation of Long-Term Stable and Flexible CsPbBr3 Perovskite Quantum Dots/Ethylene Vinyl Acetate Copolymer Composite Films for White Light-Emitting Diodes.

    PubMed

    Li, Yang; Lv, Ying; Guo, Ziquan; Dong, Liubing; Zheng, Jianghui; Chai, Chufen; Chen, Nan; Lu, Yijun; Chen, Chao

    2018-05-09

    CsPbBr 3 perovskite quantum dots (PQDs)/ethylene vinyl acetate (EVA) composite films were prepared via a one-step method; on the basis of this, both supersaturated recrystallization of CsPbBr 3 PQDs and dissolution of EVA were realized in toluene. The prepared films display outstanding green-emitting performance with high color purity of 92% and photoluminescence (PL) quantum yield of 40.5% at appropriate CsPbBr 3 PQD loading. They possess long-term stable luminescent properties in the air and in water, benefiting from the effective protection of CsPbBr 3 PQDs by the EVA matrix. Besides, the prepared CsPbBr 3 PQDs/EVA films are flexible enough to be repeatedly bent for 1000 cycles while keeping unchanged the PL intensity. The optical properties of the CsPbBr 3 PQDs/EVA films in white light-emitting diodes were also studied by experiments and theoretical simulation. Overall, facile preparation process, good long-term stability, and high flexibility allow our green-emitting CsPbBr 3 PQDs/EVA films to be applied in lighting applications and flexible displays.

  11. Ethylene-Vinyl Acetate Potential Problems for Photovoltaic Packaging: Preprint

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kempe, M. D.; Jorgensen, G. J.; Terwilliger, K. M.

    2006-05-01

    Photovoltaic (PV) devices are typically encapsulated using ethylene-vinyl acetate (EVA) to provide mechanical support, optical coupling, electrical isolation, and protection against environmental exposure. Under exposure to atmospheric water and/or ultraviolet radiation, EVA will decompose to produce acetic acid, lowering the pH and increasing the surface corrosion rates of embedded devices. Even though acetic acid is produced at a very slow rate, it may not take much to catalyze reactions that lead to rapid module deterioration. Another consideration is that the glass transition of EVA, as measured using dynamic mechanical analysis, begins at temperatures of about ?15 C. Temperatures lower thanmore » this can be reached for extended periods of time in some climates. Because of increased moduli below the glass transition temperature, a module may be more vulnerable to damage if a mechanical load is applied by snow or wind at low temperatures. Modules using EVA should not be rated for use at such low temperatures without additional low-temperature mechanical testing beyond the scope of UL 1703.« less

  12. Modified EVA Encapsulant Formulations for Low Temperature Processing: Preprint

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mei, Z.; Pern, F. J.; Glick, S. H.

    2001-10-01

    Presented at the 2001 NCPV Program Review Meeting: We have developed several new ethylene-vinyl acetate (EVA) formulations modified on the basis of NREL patented EVA formulations [1]. The new formulations can be cured to a desired gel content of {approx}80% in the ambient at temperatures 20-30 C lower than the typical conditions in vacuum (i.e. {approx}150 C). Glass/glass laminates showed transmittance spectra that are essentially the same as that of EVA 15295P in the visible and NIR regions but higher in the UV region. Results of fluorescence analysis of the ambient-processed new EVA formulations showed the concentrations of the curing-generatedmore » {alpha},{beta}-unsaturated carbonyl chromophores, which are responsible for the UV induced EVA discoloration and photodegradation, were considerably lower than that of EVA 15295P, therefore suggesting a better photochemical stability of new EVA formulations.« less

  13. Potential Problems with Ethylene-Vinyl Acetate for Photovoltaic Packaging (Poster)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kempe, M. D.; Jorgensen, G. J.; Terwilliger, K, M.

    2006-05-01

    Photovoltaic (PV) devices are typically encapsulated using ethylene-vinyl acetate (EVA) to provide mechanical support electrical isolation, optical coupling, and protection against environmental exposure. Under exposure to atmospheric water and/or ultraviolet radiation, EVA will decompose to produce acetic acid, lowering the pH and increasing the surface corrosion rates of embedded devices. Even though acetic acid is produced at a very slow rate it may not take much to catalyze reactions that lead to rapid module deterioration. Another consideration is that the glass transition of EVA, as measured using dynamic mechanical analysis, begins at temperatures of about -15 C. Temperatures lower thanmore » this can be reached for extended periods of time in some climates. Due to increased moduli below the glass transition temperature, a module may be more vulnerable to damage if a mechanical load is applied by snow or wind at low temperatures. Modules using EVA should not be rated for use at such low temperatures without additional low-temperature mechanical testing beyond the scope of UL 1703.« less

  14. ESEM analysis of polymeric film in EVA-modified cement paste

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Silva, D.A.; Monteiro, P.J.M.

    2005-10-01

    Portland cement pastes modified by 20% weight (polymer/cement ratio) of poly(ethylene-co-vinyl acetate) (EVA) were prepared, cured, and immersed in water for 11 days. The effects of water saturation and drying on the EVA polymeric film formed in cement pastes were observed using environmental scanning electron microscopy (ESEM). This technique allowed the imaging of the EVA film even in saturated samples. The decrease of the relative humidity inside the ESEM chamber did not cause any visual modification of the polymeric film during its drying.

  15. Influence of menthol and pressure-sensitive adhesives on the in vivo performance of membrane-moderated transdermal therapeutic system of nicardipine hydrochloride in human volunteers.

    PubMed

    Krishnaiah, Y S R; Satyanarayana, V; Bhaskar, P

    2003-05-01

    A membrane-moderated transdermal therapeutic system of nicardipine hydrochloride was developed using 2% w/w hydroxypropylcellulose (HPC) gel as a reservoir system containing 5% w/w of menthol as a penetration enhancer. The permeability flux of nicardipine hydrochloride through the ethylene vinyl acetate (EVA) copolymer membrane was found to increase with an increase in vinyl acetate content in the copolymer. The effect of various pressure-sensitive adhesives (MA-31, MA-38 or TACKWHITE A 4MED on the permeability of nicardipine hydrochloride through EVA 2825 membrane (28% w/w vinyl acetate) or EVA 2825 membrane/skin composite was also studied. The results showed that nicardipine hydrochloride permeability through EVA 2825 membrane coated with TACKWHITE A 4MED/skin composite was higher than that coated with MA-31 or MA-38. Thus, a new transdermal therapeutic system for nicardipine hydrochloride was formulated using EVA 2825 membrane coated with a pressure-sensitive adhesive TACKWHITE A 4MED, and 2% w/w HPC gel as reservoir containing 5% w/w of menthol as a penetration enhancer. In vivo studies in healthy human volunteers indicated that the TTS of nicardipine hydrochloride, designed in the present study, provided steady-state plasma concentration of the drug with minimal fluctuations for 26h with improved bioavailability in comparison with the immediate release capsule dosage form.

  16. Formulation and in vivo evaluation of membrane-moderated transdermal therapeutic systems of nicardipine hydrochloride using carvone as a penetration enhancer.

    PubMed

    Krishnaiah, Y S R; Satyanarayana, V; Bhaskar, P

    2003-01-01

    A membrane-moderated transdermal therapeutic system (TTS) of nicardipine hydrochloride was developed using 2%w/w hydroxy propyl cellulose (HPC) gel as a reservoir system containing 8%w/w of carvone as a penetration enhancer. The permeability flux of nicardipine hydrochloride through ethylene vinyl acetate (EVA) copolymer membrane was found to increase with an increase in vinyl acetate content in the copolymer. The effect of various pressure-sensitive adhesives (MA-31, MA-38, or TACKWHITE A 4MED) on the permeability of nicardipine hydrochloride through EVA 2825 membrane (28%w/w vinyl acetate) or EVA 2825 membrane/skin composite also was studied. The results showed that nicardipine hydrochloride permeability through EVA 2825 membrane coated with TACKWHITE A 4MED/skin composite was higher than that coated with MA-31 or MA-38. Thus, a new TTS for nicardipine hydrochloride was formulated using EVA 2825 membrane coated with a pressure-sensitive adhesive TACKWHITE A 4MED and 2%w/w HPC gel as reservoir containing 8%w/w of carvone as a penetration enhancer. The bioavailability studies in healthy human volunteers indicated that the TTS of nicardipine hydrochloride, designed in the present study, provided steady-state plasma concentration of the drug with minimal fluctuations for 23 hr with improved bioavailability in comparison with the immediate-release capsule dosage form.

  17. Wax inhibitor based on ethylene vinyl acetate with methyl methacrylate and diethanolamine for crude oil pipeline

    NASA Astrophysics Data System (ADS)

    Anisuzzaman, S. M.; Abang, S.; Bono, A.; Krishnaiah, D.; Karali, R.; Safuan, M. K.

    2017-06-01

    Wax precipitation and deposition is one of the most significant flow assurance challenges in the production system of the crude oil. Wax inhibitors are developed as a preventive strategy to avoid an absolute wax deposition. Wax inhibitors are polymers which can be known as pour point depressants as they impede the wax crystals formation, growth, and deposition. In this study three formulations of wax inhibitors were prepared, ethylene vinyl acetate, ethylene vinyl acetate co-methyl methacrylate (EVA co-MMA) and ethylene vinyl acetate co-diethanolamine (EVA co-DEA) and the comparison of their efficiencies in terms of cloud point¸ pour point, performance inhibition efficiency (%PIE) and viscosity were evaluated. The cloud point and pour point for both EVA and EVA co-MMA were similar, 15°C and 10-5°C, respectively. Whereas, the cloud point and pour point for EVA co-DEA were better, 10°C and 10-5°C respectively. In conclusion, EVA co-DEA had shown the best % PIE (28.42%) which indicates highest percentage reduction of wax deposit as compared to the other two inhibitors.

  18. The impact of electron beam irradiation on Low density polyethylene and Ethylene vinyl acetate

    NASA Astrophysics Data System (ADS)

    Sabet, Maziyar; Soleimani, Hassan

    2017-05-01

    Improvement of measured gel content, hardness, tensile strength and elongation at break of Ethylene vinyl acetate (EVA) have confirmed positive effect of electron beam irradiation on EVA. Results obtained from both gel content tests show that degree of cross-linking in amorphous regions is dependent on dose. A significant improvement in tensile strength of neat EVA samples is obtained upon electron-beam radiation up to 210 kGy. Similarly, hardness properties of Low-density polyethylene (LDPE) improvewith increasing electron beam irradiation. This article deals with the impacts of electron beam (EB) irradiation on the properties of LDPE and Ethylene-Vinyl Acetate (EVA) as the two common based formulations for wire and cable applications.

  19. Pyrolysis-gas chromatography-mass spectrometry for studying N-vinyl-2-pyrrolidone-co-vinyl acetate copolymers and their dissolution behaviour.

    PubMed

    Chojnacka, Aleksandra; Ghaffar, Abdul; Feilden, Andrew; Treacher, Kevin; Janssen, Hans-Gerd; Schoenmakers, Peter

    2011-11-14

    Knowledge on the solubility behaviour and dissolution rate of speciality and commodity polymers is very important for the use of such materials in high-tech applications. We have developed methods for the quantification and characterization of dissolved copolymers of N-vinyl-2-pyrrolidone (VP) and vinyl acetate (VA) during dissolution in water. The methods are based on pyrolysis (Py) performed in a programmed-temperature vaporization injector with subsequent identification and quantification of the components in the pyrolysate using capillary gas chromatography-mass spectrometry (GC-MS). By injecting large volumes and applying cryo-focussing at the top of the column, low detection limits could be achieved. The monomer ratio was found to have the greatest effect on the dissolution rate of the PVP-co-VA copolymers. The material with the highest amount of VA (50%) dissolves significantly slower than the other grades. Size-exclusion chromatography (SEC) and Py-GC-MS were used to measure molecular weights and average chemical compositions, respectively. Combined off-line SEC//Py-GC-MS was used to determine the copolymer composition (VP/VA ratio), as a function of the molecular weight for the pure polymers. In the dissolution experiments, a constant VP/VA ratio across the dissolution curve was observed for all copolymers analysed. This suggests a random distribution of the two monomers over the molecules. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Barrier properties of PE, PP and EVA (nano)composites - The influence of filler type and concentration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Merinska, D.; Kalendova, A.; Tesarikova, A.

    2014-05-15

    Nanocomposite materials with layered clay used as nanofiller and polyethylene (PE), polypropylene (PP) and copolymer ethylene and vinyl acetate matrix (EVA, the content of VA component 19 wt. %) were prepared by compounding the individual components in Brabender kneader. The MMT Na+ and four types of commercial products such as Nanofil N 5 and N3000, Cloisite 93A and 30B were used as nanofillers. Next to the clays microprecipitated CaHCO{sub 3}, nanosilica and Halloysite tubes were used. The quantity of all the above-mentioned (nano)fillers was 1, 3 and 5 wt. % in relation to the content of montmorillonite. The aim wasmore » to evaluate the influence of (nano)filler type and concentration on nanocomposite barrier properties. The morphology of nanocomposite samples was examined by means of XRD analysis illustrated by transmission electronic microscopy TEM. Furthermore, permeability for O{sub 2} and CO{sub 2} were observed.« less

  1. Clinical acceptability of an ethylene-vinyl-acetate nonmedicated vaginal ring.

    PubMed

    Roumen, F J; Dieben, T O

    1999-01-01

    In an open study the acceptability of a newly designed vaginal ring was evaluated. The ring being developed for contraceptive purposes was made of ethylene-vinyl-acetate copolymer (EVA). In this study the ring did not contain active medication. Three groups of 20 healthy female volunteers were asked to use rings--with a diameter of 54 mm--for 21 consecutive days; each group was assigned rings with a different cross-sectional thickness of 3, 3.5, or 4 mm. Subjects were given diary cards to report on insertion and removal of the ring and on complaints. Of the 65 women who participated, 59 completed the study and used the ring for at least 21 days, giving an acceptability of 91% (59/65). No major differences were found between the three types of rings except for a sensation of expulsion, which was reported more often in the group assigned the smallest cross-sectional-thickness ring. Expulsion was reported once during intercourse in the 3.5-mm group. Insertion and removal of the rings were judged to be easy by the overall majority of the women. The ring was felt by the partner during intercourse in 35%-50% of couples. Further development of an active combined contraceptive EVA ring with a cross-sectional thickness of 4 mm seems a reasonable option. In future studies with the active ring, allowance for temporary removal of the ring during intercourse, if preferred, may be suggested.

  2. Sorption of Aromatic Compounds with Copolymer Sorbent Materials Containing β-Cyclodextrin.

    PubMed

    Wilson, Lee D; Mohamed, Mohamed H; Berhaut, Christopher L

    2011-08-29

    Urethane copolymer sorbent materials that incorporate β-cyclodextrin (CD) have been prepared and their sorption properties with chlorinated aromatic compounds (i.e., pentachlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxy acetic acid) have been evaluated. The sorption properties of granular activated carbon (GAC) were similarly compared in aqueous solution at variable pH conditions. The sorbents displayed variable BET surface areas as follows: MDI-X copolymers (< 10¹ m²/g), CDI-X copolymers (< 10¹ m²/g), and granular activated carbon (GAC ~10³ m²/g). The sorption capacities for the copolymers sorbents are listed in descending order, as follows: GAC > CDI-3 copolymer ≈ MDI-3 copolymer. The sorption capacity for the aromatic adsorbates with each sorbent are listed in descending order, as follows: 2,4-dichlorophenol > 2,4-dichlorophenoxy acetic acid > pentachlorophenol. In general, the differences in the sorption properties of the copolymer sorbents with the chlorinated organics were related to the following factors: (i) surface area of the sorbent; (ii) CD content and accessibility; and (iii) and the chemical nature of the sorbent material.

  3. Sorption of Aromatic Compounds with Copolymer Sorbent Materials Containing β-Cyclodextrin

    PubMed Central

    Wilson, Lee D.; Mohamed, Mohamed H.; Berhaut, Christopher L.

    2011-01-01

    Urethane copolymer sorbent materials that incorporate β-cyclodextrin (CD) have been prepared and their sorption properties with chlorinated aromatic compounds (i.e., pentachlorophenol, 2,4-dichlorophenol and 2,4-dichlorophenoxy acetic acid) have been evaluated. The sorption properties of granular activated carbon (GAC) were similarly compared in aqueous solution at variable pH conditions. The sorbents displayed variable BET surface areas as follows: MDI-X copolymers (< 101 m2/g), CDI-X copolymers (< 101 m2/g), and granular activated carbon (GAC ~103 m2/g). The sorption capacities for the copolymers sorbents are listed in descending order, as follows: GAC > CDI-3 copolymer ≈ MDI-3 copolymer. The sorption capacity for the aromatic adsorbates with each sorbent are listed in descending order, as follows: 2,4-dichlorophenol > 2,4-dichlorophenoxy acetic acid > pentachlorophenol. In general, the differences in the sorption properties of the copolymer sorbents with the chlorinated organics were related to the following factors: (i) surface area of the sorbent; (ii) CD content and accessibility; and (iii) and the chemical nature of the sorbent material. PMID:28824156

  4. Current status of EVA degradation in Si modules and interface stability in CdTe/CdS modules

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Czanderna, A.W.

    1994-06-30

    The goals, objectives, background, technical approach, status, and accomplishments on the PV Module Reliability Research Task are summarized for FY 1993. The accomplishments are reported in two elements, ethylene vinyl acetate (EVA) degradation and stability in CdTe/CdS modules. The EVA results are presented under the headings modified EVA and potential EVA replacements, degradation mechanisms, efficiency losses from yellowed EVA, and equipment acquisitions. The results on CdTe/CdS modules are presented under subheadings of stability of the SnO[sub 2]/CdS interface and degradation at the CdTe/CdS interface.

  5. Thermal Conductivity of Ethylene Vinyl Acetate Copolymer/Nanofiller Blends

    NASA Technical Reports Server (NTRS)

    Ghose, S.; Watson, K. A.; Working, D. C.; Connell, J. W.; Smith, J. G., Jr.; Lin, Y.; Sun, Y. P.

    2007-01-01

    To reduce weight and increase the mobility, comfort, and performance of future spacesuits, flexible, thermally conductive fabrics and plastic tubes are needed for the Liquid Cooling and Ventilation Garment. Such improvements would allow astronauts to operate more efficiently and safely for extended extravehicular activities. As an approach to raise the thermal conductivity (TC) of an ethylene vinyl acetate copolymer (Elvax 260), it was compounded with three types of carbon based nanofillers: multi-walled carbon nanotubes (MWCNTs), vapor grown carbon nanofibers (CNFs), and expanded graphite (EG). In addition, other nanofillers including metallized CNFs, nickel nanostrands, boron nitride, and powdered aluminum were also compounded with Elvax 260 in the melt at various loading levels. In an attempt to improve compatibility between Elvax 260 and the nanofillers, MWCNTs and EG were modified by surface coating and through noncovalent and covalent attachment of organic molecules containing alkyl groups. Ribbons of the nanocomposites were extruded to form samples in which the nanofillers were aligned in the direction of flow. Samples were also fabricated by compression molding to yield nanocomposites in which the nanofillers were randomly oriented. Mechanical properties of the aligned samples were determined by tensile testing while the degree of dispersion and alignment of nanoparticles were investigated using high-resolution scanning electron microscopy. TC measurements were performed using a laser flash (Nanoflash ) technique. TC of the samples was measured in the direction of, and perpendicular to, the alignment direction. Additionally, tubing was also extruded from select nanocomposite compositions and the TC and mechanical flexibility measured.

  6. Thermal Conductivity of Ethylene Vinyl Acetate Copolymer/Nanofiller Blends

    NASA Technical Reports Server (NTRS)

    Ghose, Sayata; Watson, Kent A.; Working, Dennis C.; Connell, John W.; Smith, Joseph G., Jr.; Lin, Y.; Sun, Y. P.

    2007-01-01

    To reduce weight and increase the mobility, comfort, and performance of future spacesuits, flexible, thermally conductive fabrics and plastic tubes are needed for the Liquid Cooling and Ventilation Garment. Such improvements would allow astronauts to operate more efficiently and safely for extended extravehicular activities. As an approach to raise the thermal conductivity (TC) of an ethylene vinyl acetate copolymer (Elvax(TM)260), it was compounded with three types of carbon based nanofillers: multi-walled carbon nanotubes (MWCNTs), vapor grown carbon nanofibers (CNFs), and expanded graphite (EG). In addition, other nanofillers including metallized CNFs, nickel nanostrands, boron nitride, and powdered aluminum were also compounded with Elvax(TM) 260 in the melt at various loading levels. In an attempt to improve compatibility between Elvax 260 and the nanofillers, MWCNTs and EG were modified by surface coating and through noncovalent and covalent attachment of organic molecules containing alkyl groups. Ribbons of the nanocomposites were extruded to form samples in which the nanofillers were aligned in the direction of flow. Samples were also fabricated by compression molding to yield nanocomposites in which the nanofillers were randomly oriented. Mechanical properties of the aligned samples were determined by tensile testing while the degree of dispersion and alignment of nanoparticles were investigated using high-resolution scanning electron microscopy. TC measurements were performed using a laser flash (Nanoflash(TM)) technique. TC of the samples was measured in the direction of, and perpendicular to, the alignment direction. Additionally, tubing was also extruded from select nanocomposite compositions and the TC and mechanical flexibility measured.

  7. Viscometric investigation of compatibilization of the poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) blends by terpolymer of maleic anhydride styrene vinyl acetate

    NASA Astrophysics Data System (ADS)

    İmren, Dilek; Boztuğ, Ali; Yılmaz, Ersen; Zengin, H. Bayram

    2008-11-01

    In this study, a blend of poly(vinyl chloride) (PVC)/ethylene-co-vinyl acetate (EVA) was compatibilized by terpolymer of maleic anhydride-styrene-vinyl acetate (MAStVA) used as a compatibilizer. It was prepared the blends of 50/50 PVC/EVA containing 2-10% of the terpolymer. The compatibility experiences of these blends were investigated by using viscometric method in the range of concentrations (0.5-2.0 g dL -1) where tetrahydrofuran (THF) is the solvent. The interaction parameter (Δ b) was used to study the miscibility and compatibility of polymer blend in solution, obtained from the modified Krigbaum and Wall theory. Turbidity and FTIR measurements were also used to investigate the miscibility of this pair of polymers. The values of the relative viscosities of the each polymer solution and their blends were measured by a Cannon-Fenske type viscometer. In consequence of the study, it was observed that a considerable improvement was achieved in the miscibility of PVC/EVA blends by adding among 5 and 10 wt% of compatibilizer.

  8. Thermal processing of EVA encapsulants and effects of formulation additives

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F.J.; Glick, S.H.

    1996-05-01

    The authors investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores, in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as formulated EVA films, A9918P and 15295P, and solution-cast films of Elvaxrm (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugardmore » P{trademark}, used in the two commercial EVA formulations, greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of {approximately}80% when cured at programmed 155{degrees}C for 4 min. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.« less

  9. Mechanical behaviour study on SBR/EVA composite for FDM feedstock fabrication

    NASA Astrophysics Data System (ADS)

    Raveverma, P.; Ibrahim, M.; Sa'ude, N.; Yarwindran, M.; Nasharuddin, M.

    2017-04-01

    This paper presents the research development of a new SBR/EVA composite flexible feedstock material by the injection moulding machine. The material consists of poly (ethylene-co-vinyl acetate) in styrene butadiene rubber cross-linked by Dicumyl Peroxide. In this study, the mechanical behaviour of injection moulded SBR/EVA composite with different blend ratio investigated experimentally. The formulations of blend ratio with several combinations of a new SBR/EVA flexible feedstock was done by volume percentage (vol. %). Based on the result obtained from the mechanical testing done which is tensile and hardness the composite of SBR/EVA has the high potency to be fabricated as the flexible filament feedstock. The ratio of 80:20 which as an average hardness and tensile strength proved to be the suitable choice to be fabricated as the flexible filament feedstock. The study has reached its goals on the fabricating and testing a new PMC which is flexible.

  10. Production of targeted poly(3-hydroxyalkanoates) copolymers by glycogen accumulating organisms using acetate as sole carbon source.

    PubMed

    Dai, Yu; Yuan, Zhiguo; Jack, Kevin; Keller, Jurg

    2007-05-01

    One of the main limitations in bacterial polyhydroxyalkanoate (PHA) production with mixed cultures is the fact that primarily polyhydroxybutyrate (PHB) homopolymers are generated from acetate as the main carbon source, which is brittle and quite fragile. The incorporation of different 3-hydroxyalkanoate (HA) components into the polymers requires the addition of additional carbon sources, leading to extra costs and complexity. In this study, the production of poly(3-hydroxybutyrate (3HB)-co-3-hydroxyvalerate (3HV)-co-3-hydroxy-2-methylvalerate (3HMV)), with 7-35C-mol% of 3HV fractions from acetate as the only carbon source was achieved with the use of glycogen accumulating organisms (GAOs). An enriched GAO culture was obtained in a lab-scale reactor operated under alternating anaerobic and aerobic conditions with acetate fed at the beginning of the anaerobic period. The production of PHAs utilizing the enriched GAO culture was investigated under both aerobic and anaerobic conditions. A polymer content of 14-41% of dry cell weight was obtained. The PHA product accumulated by GAOs under anaerobic conditions contained a relatively constant proportion of non-3HB monomers (30+/-5C-mol%), irrespective of the amount of acetate assimilated. In contrast, under aerobic conditions, GAOs only produced 3HB monomers from acetate causing a gradually decreasing 3HV fraction during this aerobic feeding period. The PHAs were characterized by gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The data demonstrated that the copolymers possessed similar characteristics to those of commercially available poly(3HB-co-3HV) (PHBV) products. The PHAs produced under solely anaerobic conditions possessed lower melting points and crystallinity, higher molecular weights, and narrower molecular-weight distributions, compared to the aerobically produced polymers. This paper hence demonstrates the significant potential of GAOs to produce high quality polymers from a

  11. Characterization of Thermo-Physical Properties of EVA/ATH: Application to Gasification Experiments and Pyrolysis Modeling.

    PubMed

    Girardin, Bertrand; Fontaine, Gaëlle; Duquesne, Sophie; Försth, Michael; Bourbigot, Serge

    2015-11-20

    The pyrolysis of solid polymeric materials is a complex process that involves both chemical and physical phenomena such as phase transitions, chemical reactions, heat transfer, and mass transport of gaseous components. For modeling purposes, it is important to characterize and to quantify the properties driving those phenomena, especially in the case of flame-retarded materials. In this study, protocols have been developed to characterize the thermal conductivity and the heat capacity of an ethylene-vinyl acetate copolymer (EVA) flame retarded with aluminum tri-hydroxide (ATH). These properties were measured for the various species identified across the decomposition of the material. Namely, the thermal conductivity was found to decrease as a function of temperature before decomposition whereas the ceramic residue obtained after the decomposition at the steady state exhibits a thermal conductivity as low as 0.2 W/m/K. The heat capacity of the material was also investigated using both isothermal modulated Differential Scanning Calorimetry (DSC) and the standard method (ASTM E1269). It was shown that the final residue exhibits a similar behavior to alumina, which is consistent with the decomposition pathway of EVA/ATH. Besides, the two experimental approaches give similar results over the whole range of temperatures. Moreover, the optical properties before decomposition and the heat capacity of the decomposition gases were also analyzed. Those properties were then used as input data for a pyrolysis model in order to predict gasification experiments. Mass losses of gasification experiments were well predicted, thus validating the characterization of the thermo-physical properties of the material.

  12. Characterization of Thermo-Physical Properties of EVA/ATH: Application to Gasification Experiments and Pyrolysis Modeling

    PubMed Central

    Girardin, Bertrand; Fontaine, Gaëlle; Duquesne, Sophie; Försth, Michael; Bourbigot, Serge

    2015-01-01

    The pyrolysis of solid polymeric materials is a complex process that involves both chemical and physical phenomena such as phase transitions, chemical reactions, heat transfer, and mass transport of gaseous components. For modeling purposes, it is important to characterize and to quantify the properties driving those phenomena, especially in the case of flame-retarded materials. In this study, protocols have been developed to characterize the thermal conductivity and the heat capacity of an ethylene-vinyl acetate copolymer (EVA) flame retarded with aluminum tri-hydroxide (ATH). These properties were measured for the various species identified across the decomposition of the material. Namely, the thermal conductivity was found to decrease as a function of temperature before decomposition whereas the ceramic residue obtained after the decomposition at the steady state exhibits a thermal conductivity as low as 0.2 W/m/K. The heat capacity of the material was also investigated using both isothermal modulated Differential Scanning Calorimetry (DSC) and the standard method (ASTM E1269). It was shown that the final residue exhibits a similar behavior to alumina, which is consistent with the decomposition pathway of EVA/ATH. Besides, the two experimental approaches give similar results over the whole range of temperatures. Moreover, the optical properties before decomposition and the heat capacity of the decomposition gases were also analyzed. Those properties were then used as input data for a pyrolysis model in order to predict gasification experiments. Mass losses of gasification experiments were well predicted, thus validating the characterization of the thermo-physical properties of the material. PMID:28793682

  13. Influence of limonene on the bioavailability of nicardipine hydrochloride from membrane-moderated transdermal therapeutic systems in human volunteers.

    PubMed

    Krishnaiah, Y S R; Satyanarayana, V; Bhaskar, P

    2002-10-24

    The aim of the present study was to develop a membrane-moderated transdermal therapeutic system (TTS) of nicardipine hydrochloride using 2%w/w hydroxy propyl cellulose (HPC) gel as a reservoir system containing 4%w/w of limonene as a penetration enhancer. The permeability flux of nicardipine hydrochloride through ethylene vinyl acetate (EVA) copolymer membrane was found to increase with an increase in vinyl acetate (VA) content in the copolymer. The effect of various pressure-sensitive adhesives (MA-31, MA-38 or TACKWHITE A 4MED) on the permeability of nicardipine hydrochloride through EVA membrane 2825 (28% w/w VA) or membrane/skin composite was also studied. The results showed that nicardipine hydrochloride permeability through EVA 2825 membrane coated with TACKWHITE 4A MED/skin composite was higher than that coated with MA-31or MA-38. Thus a new TTS for nicardipine hydrochloride was formulated using EVA 2825 membrane coated with a pressure-sensitive adhesive TACKWHITE 4A MED and 2%w/w HPC gel as reservoir containing 4%w/w of limonene as a penetration enhancer. The bioavailability studies in healthy human volunteers indicated that the TTS of nicardipine hydrochloride, designed in the present study, provided steady state plasma concentration of the drug with minimal fluctuations for 20 h with improved bioavailability in comparison with the immediate release capsule dosage form. Copyright 2002 Elsevier Science B.V.

  14. Thermal Conductivity of Ethylene Vinyl Acetate Copolymer/Carbon Nanofiller Blends

    NASA Technical Reports Server (NTRS)

    Ghose, S.; Watson, K. A.; Working, D. C.; Connell, J. W.; Smith, J. G., Jr.; Lin, Y.; Sun, Y. P.

    2007-01-01

    To reduce weight and increase the mobility, comfort, and performance of future spacesuits, flexible, thermally conductive fabrics and plastic tubes are needed for the Liquid Cooling and Ventilation Garment. Such improvements would allow astronauts to operate more efficiently and safely for extended extravehicular activities. As an approach to raise the thermal conductivity (TC) of an ethylene vinyl acetate copolymer (Elvax 260), it was compounded with three types of carbon based nanofillers: multi-walled carbon nanotubes (MWCNTs), vapor grown carbon nanofibers (CNFs), and expanded graphite (EG). In addition, other nanofillers including metallized CNFs, nickel nanostrands, boron nitride, and powdered aluminum were also compounded with Elvax 260 in the melt at various loading levels. In an attempt to improve compatibility between Elvax 260 and the nanofillers, MWCNTs and EG were modified by surface coating and through noncovalent and covalent attachment of organic molecules containing alkyl groups. Ribbons of the nanocomposites were extruded to form samples in which the nanofillers were aligned in the direction of flow. Samples were also fabricated by compression molding to yield nanocomposites in which the nanofillers were randomly oriented. Mechanical properties of the aligned samples were determined by tensile testing while the degree of dispersion and alignment of nanoparticles were investigated using high-resolution scanning electron microscopy. TC measurements were performed using a laser flash (Nanoflash ) technique. TC of the samples was measured in the direction of, and perpendicular to, the alignment direction. Additionally, tubing was also extruded from select nanocomposite compositions and the TC and mechanical flexibility measured.

  15. Thermal processing of EVA encapsulants and effects of formulation additives

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F.J.; Glick, S.H.

    1996-09-01

    The authors investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films. A9918P and 15295P, and solution-cast films of Elvax{trademark} (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P{trademark},more » used in the two commercial EVA formulations, greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of {approximately}80% when cured at programmed 155 C for 4 min. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.« less

  16. Improved photostability of NREL-developed EVA pottant formulations for PV module encapsulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F.J.; Glick, S.H.

    1997-12-31

    Several new formulations of ethylene vinyl acetate (EVA)-based encapsulant have been developed at NREL and have greatly improved photostability against UV-induced discoloration. The new EVA formulations use stabilizers and a curing agent entirely different from any of those used in existing formulations known to the authors. No discoloration was observed for the laminated and cured samples that were exposed to a {approximately}5-sun UV light (300--400 nm) from a solar simulator at a black panel temperature (BPT) of 44 {+-} 2 C for {approximately}3250 h followed by at 85 C for {approximately}850 h, an equivalent of approximately 9.4 years for anmore » average 6-h daily, 1-sun solar exposure in Golden, Colorado. Under the same conditions, substantial discoloration and premature delamination were observed for two commercial EVA formulations. Encapsulation with the new EVA formulations should extend the long-term stability for PV modules in the field, especially when coupled with UV-filtering, Ce-containing glass superstrates.« less

  17. Acid-Labile Amphiphilic PEO-b-PPO-b-PEO Copolymers: Degradable Poloxamer Analogs.

    PubMed

    Worm, Matthias; Kang, Biao; Dingels, Carsten; Wurm, Frederik R; Frey, Holger

    2016-05-01

    Poly ((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers (Mn,total = 6600, 8000, 9150 g·mol(-1) ; Mn,PEO = 2200, 3600, 4750 g·mol(-1) ) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions (Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation "on demand." © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Study on structure and hydrophobicity of PP/EVA co-blending membrane: Quenching rate

    NASA Astrophysics Data System (ADS)

    Tang, Na; Li, Zhao; Hua, Xinxin

    2017-03-01

    Isotactic polypropylene (iPP)/ethylene vinyl acetate (EVA) co-blending hydrophobic microporous membranes for vacuum membrane distillation (VMD) were prepared via thermally induced phase separation (TIPS). In the process of preparation, quenching rate has a great influence on the membrane morphology.

  19. Preparation, characterization and application of EVA film containing Eu3+ complex with 1-tridecanecarboxylic acid ligand

    NASA Astrophysics Data System (ADS)

    Dong, Jin; Lin, Baoping

    2017-11-01

    In this study, on the basis of complex Eu(DBM)3Phen which was widely applied in polymer matrices, quaternary complex Eu(DBM)2Phen(TA) was synthesized by the introduction of 1-tridecanecarboxylic acid (TA). XRD analyses show that Eu(DBM)2Phen(TA) inclines to amorphization compared with Eu(DBM)3Phen which is crystal. Ethylene-vinyl acetate (EVA) film doped with Eu(DBM)2Phen(TA) was prepared by casting method. SEM and AFM analyses show that the compatibility of Eu(DBM)2Phen(TA) with EVA is better than that of Eu(DBM)3Phen with EVA. Under the same addition amount of Eu3+ complexes, visible light transmittance of Eu(DBM)2Phen(TA)/EVA film is obviously greater than that of Eu(DBM)3Phen/EVA film, and the fluorescence intensity of Eu(DBM)2Phen(TA)/EVA film is only slightly lower than that of Eu(DBM)3Phen/EVA film. With the optimum addition amount of Eu3+ complexes, the energy conversion efficiency of the polycrystalline silicon solar cell coated with Eu(DBM)2Phen(TA)/EVA film is improved to 12.14%, and in comparison, that of the solar cell coated with Eu(DBM)3Phen/EVA film is only 11.98%. Hence Eu(DBM)2Phen(TA)/EVA film has a potential prospect as luminescent down-shifting material.

  20. Influence of association of "EVA-NBR" on indirect tensile strength of modified bituminous concrete

    NASA Astrophysics Data System (ADS)

    Chinoun, M.; Soudani, K.; Haddadi, S.

    2016-04-01

    The aim of this work is to contribute to the improvement of the mechanical properties of bituminous concrete by modification of bituminous concrete. In this study, we present the results of the indirect tensile strength "ITS" of modified bituminous concrete by the combination of two modifiers, one is a plastomer EVA (Ethylene Vinyl Acetate) and the other is a industrial waste from the shoe soles grinding NBR (Nitrile Butadiene Rubber) as crumb rubber. To modify the bitumen a wet process was used. The results show that the modification of bitumen by EVA-NBR combination increases their resistance to the indirect traction "ITS" compared to the bituminous concrete control. The mixture of 5% [50% EVA+ 50% NBR] is given the best result among the other associations.

  1. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F.J.; Czanderna, A.W.

    Yellow-browning of the ethylene-vinyl acetate (EVA) copolymer encapsulant used in PV modules has resulted in significant power losses of over 50% of the initial power output. The weathering-degraded yellow-brown EVA films have lost the ultraviolet (UV) absorber, Cyasorb UV 531[sup (R)], and the degree of cross-linking (gel content) has increased. EVA degradation mechanisms identified thus far are discussed in this work. Upon exposure to UV light at 45[degree]--85 [degree]C, virgin EVA films that are stabilized with Cyasorb UV 531[sup (R)] and two antioxidants show an increase in the gel content, a gradual loss of Cyasorb by photooxidation, and the generationmore » of acetic acid. The deacetylation reaction, which leads to the formation of polyenes, also occurs significantly in the films heated in the dark at 130 [degree]C for five days. Acetic acid thermally catalyzes the EVA film discoloration at 85[degree]--130 [degree]C, which increases from a light yellow to a yellow-brown color as the heating temperature increases. The factors can account for the yellow-browning of the EVA in the accelerated testing of mini-modules, and the discoloration is more profound when exposed to UV light at 85 [degree]C than when heated in the dark at the same temperature. In the presence of the EVA-produced acetic acid, oxygen, and sunlight exposure, the Cu buslines that were coated with a thin layer of Pb-Sn alloy showed significant oxidation and metal interdiffusion, which in turn may contribute to the resistance increase and hence the current loss reported for weathered PV modules.« less

  2. Control of biofilm formation by poly-ethylene-co-vinyl acetate films incorporating nisin.

    PubMed

    Nostro, Antonia; Scaffaro, Roberto; Ginestra, Giovanna; D'Arrigo, Manuela; Botta, Luigi; Marino, Andreana; Bisignano, Giuseppe

    2010-06-01

    The aim of this study was to evaluate the effect of poly-ethylene-co-vinyl acetate (EVA) films incorporating different concentrations (0.1%, 0.5% and 1%) of nisin on the biofilm-forming ability of Listeria monocytogenes ATCC 7644, Staphylococcus aureus 815 and Staphylococcus epidermidis ATCC 35984. Nisin was incorporated into two grades of EVA (EVA14 and EVA28) in the melt during a common film-blowing operation. The efficacy of EVA/nisin films was evaluated by biofilm biomass measurements and Live/Dead staining in combination with fluorescence microscopy. In order to evaluate whether the nisin incorporation could modify the film surface properties, contact angle measurements and scanning electron microscopy were performed. The results revealed the efficacy of EVA14/nisin films in reducing biofilm formation on their surfaces with more evident effect for S. epidermidis than L. monocytogenes and S. aureus strains. In contrast, EVA28/nisin films showed unsatisfactory activity. Fluorescence microscopy confirmed poor biofilm formation on EVA14/nisin films, also characterised by the presence of dead cells. The data presented in this study offer new potential applications for developing strategies aimed to improve the effect of antimicrobial agents.

  3. Role of EVA viscoelastic properties in the protective performance of a sport shoe: computational studies.

    PubMed

    Even-Tzur, Nurit; Weisz, Ety; Hirsch-Falk, Yifat; Gefen, Amit

    2006-01-01

    Modern sport shoes are designed to attenuate mechanical stress waves, mainly through deformation of the viscoelastic midsole which is typically made of ethylene vinyl acetate (EVA) foam. Shock absorption is obtained by flow of air through interconnected air cells in the EVA during shoe deformation under body-weight. However, when the shoe is overused and air cells collapse or thickness of the EVA is reduced, shock absorption capacity may be affected, and this may contribute to running injuries. Using lumped system and finite element models, we studied heel pad stresses and strains during heel-strike in running, considering the viscoelastic constitutive behavior of both the heel pad and EVA midsole. In particular, we simulated wear cases of the EVA, manifested in the modeling by reduced foam thickness, increased elastic stiffness, and shorter stress relaxation with respect to new shoe conditions. Simulations showed that heel pad stresses and strains were sensitive to viscous damping of the EVA. Wear of the EVA consistently increased heel pad stresses, and reduced EVA thickness was the most influential factor, e.g., for a 50% reduction in thickness, peak heel pad stress increased by 19%. We conclude that modeling of the heel-shoe interaction should consider the viscoelastic properties of the tissue and shoe components, and the age of the studied shoe.

  4. Exploration EVA System

    NASA Technical Reports Server (NTRS)

    Kearney, Lara

    2004-01-01

    In January 2004, the President announced a new Vision for Space Exploration. NASA's Office of Exploration Systems has identified Extravehicular Activity (EVA) as a critical capability for supporting the Vision for Space Exploration. EVA is required for all phases of the Vision, both in-space and planetary. Supporting the human outside the protective environment of the vehicle or habitat and allow ing him/her to perform efficient and effective work requires an integrated EVA "System of systems." The EVA System includes EVA suits, airlocks, tools and mobility aids, and human rovers. At the core of the EVA System is the highly technical EVA suit, which is comprised mainly of a life support system and a pressure/environmental protection garment. The EVA suit, in essence, is a miniature spacecraft, which combines together many different sub-systems such as life support, power, communications, avionics, robotics, pressure systems and thermal systems, into a single autonomous unit. Development of a new EVA suit requires technology advancements similar to those required in the development of a new space vehicle. A majority of the technologies necessary to develop advanced EVA systems are currently at a low Technology Readiness Level of 1-3. This is particularly true for the long-pole technologies of the life support system.

  5. EVA Wiki - Transforming Knowledge Management for EVA Flight Controllers and Instructors

    NASA Technical Reports Server (NTRS)

    Johnston, Stephanie S.; Alpert, Brian K.; Montalvo, Edwin James; Welsh, Lawrence Daren; Wray, Scott; Mavridis, Costa

    2016-01-01

    The EVA Wiki was recently implemented as the primary knowledge database to retain critical knowledge and skills in the EVA Operations group at NASA's Johnson Space Center by ensuring that information is recorded in a common, easy to search repository. Prior to the EVA Wiki, information required for EVA flight controllers and instructors was scattered across different sources, including multiple file share directories, SharePoint, individual computers, and paper archives. Many documents were outdated, and data was often difficult to find and distribute. In 2011, a team recognized that these knowledge management problems could be solved by creating an EVA Wiki using MediaWiki, a free and open-source software developed by the Wikimedia Foundation. The EVA Wiki developed into an EVA-specific Wikipedia on an internal NASA server. While the technical implementation of the wiki had many challenges, one of the biggest hurdles came from a cultural shift. Like many enterprise organizations, the EVA Operations group was accustomed to hierarchical data structures and individually-owned documents. Instead of sorting files into various folders, the wiki searches content. Rather than having a single document owner, the wiki harmonized the efforts of many contributors and established an automated revision controlled system. As the group adapted to the wiki, the usefulness of this single portal for information became apparent. It transformed into a useful data mining tool for EVA flight controllers and instructors, as well as hundreds of others that support the EVA. Program managers, engineers, astronauts, flight directors, and flight controllers in differing disciplines now have an easier-to-use, searchable system to find EVA data. This paper presents the benefits the EVA Wiki has brought to NASA's EVA community, as well as the cultural challenges it had to overcome.

  6. EVA Wiki - Transforming Knowledge Management for EVA Flight Controllers and Instructors

    NASA Technical Reports Server (NTRS)

    Johnston, Stephanie S.; Alpert, Brian K.; Montalvo, Edwin James; Welsh, Lawrence Daren; Wray, Scott; Mavridis, Costa

    2016-01-01

    The EVA Wiki was recently implemented as the primary knowledge database to retain critical knowledge and skills in the EVA Operations group at NASA's Johnson Space Center by ensuring that information is recorded in a common, easy to search repository. Prior to the EVA Wiki, information required for EVA flight controllers and instructors was scattered across different sources, including multiple file share directories, SharePoint, individual computers, and paper archives. Many documents were outdated, and data was often difficult to find and distribute. In 2011, a team recognized that these knowledge management problems could be solved by creating an EVA Wiki using MediaWiki, a free and open-source software developed by the Wikimedia Foundation. The EVA Wiki developed into an EVA-specific Wikipedia on an internal NASA server. While the technical implementation of the wiki had many challenges, one of the biggest hurdles came from a cultural shift. Like many enterprise organizations, the EVA Operations group was accustomed to hierarchical data structures and individually-owned documents. Instead of sorting files into various folders, the wiki searches content. Rather than having a single document owner, the wiki harmonized the efforts of many contributors and established an automated revision controlled system. As the group adapted to the wiki, the usefulness of this single portal for information became apparent. It transformed into a useful data mining tool for EVA flight controllers and instructors, as well as hundreds of others that support EVA. Program managers, engineers, astronauts, flight directors, and flight controllers in differing disciplines now have an easier-to-use, searchable system to find EVA data. This paper presents the benefits the EVA Wiki has brought to NASA's EVA community, as well as the cultural challenges it had to overcome.

  7. EVA worksite analysis--use of computer analysis for EVA operations development and execution.

    PubMed

    Anderson, D

    1999-01-01

    To sustain the rate of extravehicular activity (EVA) required to assemble and maintain the International Space Station, we must enhance our ability to plan, train for, and execute EVAs. An underlying analysis capability has been developed to ensure EVA access to all external worksites as a starting point for ground training, to generate information needed for on-orbit training, and to react quickly to develop contingency EVA plans, techniques, and procedures. This paper describes the use of computer-based EVA worksite analysis techniques for EVA worksite design. EVA worksite analysis has been used to design 80% of EVA worksites on the U.S. portion of the International Space Station. With the launch of the first U.S. element of the station, EVA worksite analysis is being developed further to support real-time analysis of unplanned EVA operations. This paper describes this development and deployment of EVA worksite analysis for International Space Station (ISS) mission support.

  8. Tracking Historical NASA EVA Training: Lifetime Surveillance of Astronaut Health (LSAH) Development of the EVA Suit Exposure Tracker (EVA SET)

    NASA Technical Reports Server (NTRS)

    Laughlin, Mitzi S.; Murray, Jocelyn D.; Lee, Lesley R.; Wear, Mary L.; Van Baalen, Mary

    2017-01-01

    During a spacewalk, designated as extravehicular activity (EVA), an astronaut ventures from the protective environment of the spacecraft into the vacuum of space. EVAs are among the most challenging tasks during a mission, as they are complex and place the astronaut in a highly stressful environment dependent on the spacesuit for survival. Due to the complexity of EVA, NASA has conducted various training programs on Earth to mimic the environment of space and to practice maneuvers in a more controlled and forgiving environment. However, rewards offset the risks of EVA, as some of the greatest accomplishments in the space program were accomplished during EVA, such as the Apollo moonwalks and the Hubble Space Telescope repair missions. Water has become the environment of choice for EVA training on Earth, using neutral buoyancy as a substitute for microgravity. During EVA training, an astronaut wears a modified version of the spacesuit adapted for working in water. This high fidelity suit allows the astronaut to move in the water while performing tasks on full-sized mockups of space vehicles, telescopes, and satellites. During the early Gemini missions, several EVA objectives were much more difficult than planned and required additional time. Later missions demonstrated that "complex (EVA) tasks were feasible when restraints maintained body position and underwater simulation training ensured a high success probability".1,2 EVA training has evolved from controlling body positioning to perform basic tasks to complex maintenance of the Hubble Space Telescope and construction of the International Space Station (ISS). Today, preparation is centered at special facilities built specifically for EVA training, such as the Neutral Buoyancy Laboratory (NBL) at NASA's Johnson Space Center ([JSC], Houston) and the Hydrolab at the Gagarin Cosmonaut Training Centre ([GCTC], Star City, outside Moscow). Underwater training for an EVA is also considered hazardous duty for NASA

  9. Characterisation of polyhydroxyalkanoate copolymers with controllable four-monomer composition.

    PubMed

    Dai, Yu; Lambert, Lynette; Yuan, Zhiguo; Keller, Jurg

    2008-03-20

    Polyhydroxyalkanoate (PHA) copolymers comprising the four monomers 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxy-2-methylvalerate (3HMV) and 3-hydroxy-2-methylbutyrate (3HMB) were generated using the recently discovered Defluviicoccus vanus-related glycogen accumulating organisms (DvGAOs) under anaerobic conditions without applying any nutrient limitations. The composition could be manipulated in a defined range by modifying the ratio of propionate and acetate provided in the feed stream. The PHAs produced were characterised as random copolymers (from propionate alone) or a mixture of random copolymers (from mixture of propionate and acetate) through microstructure analysis using 13C NMR spectroscopy. The sequence distribution of all eight comonomer pairs in the carbonyl region of 3HB and 3HV was identified and assigned with confidence utilising two-dimensional heteronuclear multiple bond coherence (HMBC) spectroscopy. Weight average molecular weights were in the range 390-560 kg/mol. Differential scanning calorimetry (DSC) traces showed that the melting temperature (Tm) varied between 70 and 161 degrees C and glass transition temperature (Tg) ranged from -8 to 0 degrees C. The incorporation of considerable amounts of 3HMV and 3HMB monomer units introduced additional "defects" into the PHBV copolymer structure and hence greatly lowered the crystallinity. The data indicate the potential of these four-monomer PHAs to be employed for practical applications, considering their favourable properties and the cost-effective production process using a mixed culture and simple carbon sources.

  10. Risk Management in EVA

    NASA Technical Reports Server (NTRS)

    Hall, Jonathan; Lutomski, M.

    2006-01-01

    This viewgraph presentation reviews the use of risk management in Extravehicular Activities (EVA). The contents include: 1) EVA Office at NASA - JSC; 2) EVA Project Risk Management: Why and When; 3) EVA Office Risk Management: How; 4) Criteria for Closing a Risk; 5) Criteria for Accepting a Risk; 6) ISS IRMA Reference Card Data Entry Requirement s; 7) XA/ EVA Office Risk Activity Summary; 8) EVA Significant Change Summary; 9) Integrated Risk Management Application (XA) Matrix, March 31, 2004; 10) ISS Watch Item: 50XX Summary Report; and 11) EVA Project RM Usefulness

  11. Improved crystallinity and dynamic mechanical properties of reclaimed waste tire rubber/EVA blends under the influence of electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Ramarad, Suganti; Ratnam, Chantara T.; Khalid, Mohammad; Chuah, Abdullah Luqman; Hanson, Svenja

    2017-01-01

    Dependence on automobiles has led to a huge amount of waste tires produced annually around the globe. In this study, the feasibility of recycling these waste tires by blending reclaimed waste tire rubber (RTR) with poly(ethylene-co-vinyl acetate) (EVA) and electron beam irradiation was studied. The RTR/EVA blends containing 100-0 wt% of RTR were prepared in the internal mixer followed by electron beam (EB) irradiation with doses ranging from 50 to 200 kGy. The processing torques, calorimetric and dynamic mechanical properties of the blends were studied. Blends were found to have lower processing torque indicating easier processability of RTR/EVA blends compared to EVA. RTR domains were found to be dispersed in EVA matrix, whereas, irradiation improved the dispersion of RTR into smaller domains in EVA matrix. Results showed the addition of EVA improves the efficiency of irradiation induced crosslink formation and dynamic mechanical properties of the blends at the expense of the calorimetric properties. Storage and loss modulus of 50 wt% RTR blend was higher than RTR and EVA, suggesting partial miscibility of the blend. Whereas, electron beam irradiation improved the calorimetric properties and dynamic mechanical properties of the blends through redistribution of RTR in smaller domain sizes within EVA.

  12. EVA Wiki - Transforming Knowledge Management for EVA Flight Controllers and Instructors

    NASA Technical Reports Server (NTRS)

    Johnston, Stephanie

    2016-01-01

    The EVA (Extravehicular Activity) Wiki was recently implemented as the primary knowledge database to retain critical knowledge and skills in the EVA Operations group at NASA's Johnson Space Center by ensuring that information is recorded in a common, searchable repository. Prior to the EVA Wiki, information required for EVA flight controllers and instructors was scattered across different sources, including multiple file share directories, SharePoint, individual computers, and paper archives. Many documents were outdated, and data was often difficult to find and distribute. In 2011, a team recognized that these knowledge management problems could be solved by creating an EVA Wiki using MediaWiki, a free and open-source software developed by the Wikimedia Foundation. The EVA Wiki developed into an EVA-specific Wikipedia on an internal NASA server. While the technical implementation of the wiki had many challenges, the one of the biggest hurdles came from a cultural shift. Like many enterprise organizations, the EVA Operations group was accustomed to hierarchical data structures and individually-owned documents. Instead of sorting files into various folders, the wiki searches content. Rather than having a single document owner, the wiki harmonized the efforts of many contributors and established an automated revision control system. As the group adapted to the wiki, the usefulness of this single portal for information became apparent. It transformed into a useful data mining tool for EVA flight controllers and instructors, and also for hundreds of other NASA and contract employees. Program managers, engineers, astronauts, flight directors, and flight controllers in differing disciplines now have an easier-to-use, searchable system to find EVA data. This paper presents the benefits the EVA Wiki has brought to NASA's EVA community, as well as the cultural challenges it had to overcome.

  13. Advanced EVA system design requirements study: EVAS/space station system interface requirements

    NASA Technical Reports Server (NTRS)

    Woods, T. G.

    1985-01-01

    The definition of the Extravehicular Activity (EVA) systems interface requirements and accomodations for effective integration of a production EVA capability into the space station are contained. A description of the EVA systems for which the space station must provide the various interfaces and accomodations are provided. The discussion and analyses of the various space station areas in which the EVA interfaces are required and/or from which implications for EVA system design requirements are derived, are included. The rationale is provided for all EVAS mechanical, fluid, electrical, communications, and data system interfaces as well as exterior and interior requirements necessary to facilitate EVA operations. Results of the studies supporting these discussions are presented in the appendix.

  14. ChEVAS: Combining Suprarenal EVAS with Chimney Technique

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Torella, Francesco, E-mail: f.torella@liverpool.ac.uk; Chan, Tze Y., E-mail: tze.chan@rlbuht.nhs.uk; Shaikh, Usman, E-mail: usman.shaikh@rlbuht.nhs.uk

    2015-10-15

    Endovascular sealing with the Nellix{sup ®} endoprosthesis (EVAS) is a new technique to treat infrarenal abdominal aortic aneurysms. We describe the use of endovascular sealing in conjunction with chimney stents for the renal arteries (chEVAS) in two patients, one with a refractory type Ia endoleak and an expanding aneurysm, and one with a large juxtarenal aneurysm unsuitable for fenestrated endovascular repair (EVAR). Both aneurysms were successfully excluded. Our report confirms the utility of chEVAS in challenging cases, where suprarenal seal is necessary. We suggest that, due to lack of knowledge on its durability, chEVAS should only been considered when moremore » conventional treatment modalities (open repair and fenestrated EVAR) are deemed difficult or unfeasible.« less

  15. Examination of a Standardized Test for Evaluating the Degree of Cure of EVA Encapsulation (Presentation)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, D.; Wohlgemuth, J.; Gu, X.

    2013-11-01

    The curing of cross-linkable encapsulation is a critical consideration for photovoltaic (PV) modules manufactured using a lamination process. Concerns related to ethylene-co-vinyl acetate (EVA) include the quality (e.g., expiration and uniformity) of the films or completion (duration) of the cross-linking of the EVA within a laminator. Because these issues are important to both EVA and module manufacturers, an international standard has recently been proposed by the Encapsulation Task-Group within the Working Group 2 (WG2) of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC82) for the quantification of the degree of cure for EVA encapsulation. The present draft of themore » standard calls for the use of differential scanning calorimetry (DSC) as the rapid, enabling secondary (test) method. Both the residual enthalpy- and melt/freeze-DSC methods are identified. The DSC methods are calibrated against the gel content test, the primary (reference) method. Aspects of other established methods, including indentation and rotor cure metering, were considered by the group. Key details of the test procedure will be described.« less

  16. Development of an EVA systems cost model. Volume 3: EVA systems cost model

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The EVA systems cost model presented is based on proposed EVA equipment for the space shuttle program. General information on EVA crewman requirements in a weightless environment and an EVA capabilities overview are provided.

  17. Effects of multilayered bags vs ethylvinyl-acetate bags on oxidation of parenteral nutrition.

    PubMed

    Balet, Antònia; Cardona, Daniel; Jané, Salvador; Molins-Pujol, Antoni M; Sánchez Quesada, José Luís; Gich, Ignasi; Mangues, Ma Antònia

    2004-01-01

    We evaluate the effects of multilayered bags vs ethylvinyl-acetate bags on peroxidate formation of various emulsions for all-in-one total parenteral nutrition solutions (TPN) during storage. Twenty-four parenteral nutritions were prepared with 4 commercial i.v. lipid emulsions (Soyacal 20%, Grifols; Intralipid 20%, Fresenius-Kabi; Lipofundina 20%, Braun; and Clinoleic 20%, Clintex) and 2 different bags (multilayered [ML] bag, Miramed; and 1 ethylvinyl-acetate [EVA] bag, Miramed). Each kind of TPN was prepared in triplicate. Samples were taken at 3 different times: immediately after preparation (time 0), after 6 days at 4 degrees C and 48 hours at 37 degrees C (time 1), and finally after a total of 14 days at 37 degrees C (time 2). Oxidation of TPN was evaluated by analysis of hydroperoxides by ferrous oxidation-xylenol orange (FOX) reactive, lipoperoxides by thiobarbituric acid reactive species (TBARS), alpha-tocopherol by high-performance liquid chromatography (HPLC), and ascorbic acid and dehydroascorbic acid by HPLC. TPN admixtures in ML bag showed less oxidation evaluated by peroxide determination using FOX than EVA bag. Lipoperoxides by TBARS did not show significant differences between 2 bags. Ascorbic acid and dehydroascorbic acid disappeared in EVA bags at time 1. No important differences were found in alpha-tocopherol content. Multilayered bags minimize oxidation.

  18. Ethylene-vinyl acetate foam as a new lung substitute in radiotherapy.

    PubMed

    Marqués, Enrique; Mancha, Pedro J

    2018-04-01

    The purpose of this study was to evaluate ethylene-vinyl acetate (EVA) foam as a new lung substitute in radiotherapy and to study its physical and dosimetric characteristics. We calculated the ideal vinyl acetate (VA) content of EVA foam sheets to mimic the physical and dosimetric characteristics of the ICRU lung tissue. We also computed the water-to-medium mass collision stopping power ratios, mass attenuation coefficients, CT numbers, effective atomic numbers and electron densities for: ICRU lung tissue, the RANDO commercial phantom, scaled WATER and EVA foam sheets with varying VA contents in a range between the minimum and maximum values supplied by the manufacturer. For all these substitutes, we simulated percent depth-dose curves with EGSnrc Monte Carlo (MC PDDs) in a water-lung substitute-water slab phantom expressed as dose-to-medium and dose-to-water for 3 × 3- and 10 × 10-cm 2 field sizes. PDD for the 10 × 10-cm 2 field size was also calculated with the MultiGrid Superposition algorithm (MGS PDD) for a relative electron density to water ratio of 0.26. The latter was compared with the MC PDDs in dose-to-water for scaled WATER and EVA foam sheets with the VA content that was most similar to the calculated ideal content that is physically achievable in practice. We calculated an ideal VA content of 55%; however, the maximum physically achievable content with current manufacturing techniques is 40%. The physical characteristics of the EVA foam sheets with a VA content of 40% (EVA40) are very close to those of the ICRU lung reference. The physical densities of the EVA40 foam sheets ranged from 0.030 to 0.965 g/cm 3 , almost covering the entire physical density range of the inflated/deflated lung (0.260-1.050 g/cm 3 ). Its mass attenuation coefficient at the effective energy of a 6-MV photon beam agrees within 0.8% of the ICRU reference value, and its CT number agrees within 6 HU. The effective atomic number for EVA40 varies by less than 0.42 of the

  19. Real-Time EVA Troubleshooting

    NASA Technical Reports Server (NTRS)

    Leestma, David

    2013-01-01

    David Leestma was EV-1 for the STS-41G extravehicular activity (EVA) with Kathy Sullivan (first American female spacewalker). They conducted an EVA to fully demonstrate the feasibility of refueling satellites from the Space Shuttle, and performed the first contingency EVA task involving the Ku-band antenna. STS-41G was the fourth Space Shuttle mission to perform an EVA, and Leestma related his experiences with training, the spacesuit, and EVA tasks that were conducted on October 11, 1984 during this mission.

  20. Extravehicular Activity (EVA) Hardware & Operations Overview

    NASA Technical Reports Server (NTRS)

    Moore, Sandra; Marmolejo, Jose

    2014-01-01

    The objectives of this presentation are to: Define Extravehicular Activity (EVA), identify the reasons for conducting an EVA, and review the role that EVA has played in the space program; Identify the types of EVAs that may be performed; Describe some of the U.S. Space Station equipment and tools that are used during an EVA, such as the Extravehicular Mobility Unit (EMU), the Simplified Aid For EVA Rescue (SAFER), the International Space Station (ISS) Joint Airlock and Russian Docking Compartment 1 (DC-1), and EVA Tools & Equipment; Outline the methods and procedures of EVA Preparation, EVA, and Post-EVA operations; Describe the Russian spacesuit used to perform an EVA; Provide a comparison between U.S. and Russian spacesuit hardware and EVA support; and Define the roles that different training facilities play in EVA training.

  1. EVA-SCRAM operations

    NASA Technical Reports Server (NTRS)

    Flanigan, Lee A.; Tamir, David; Weeks, Jack L.; Mcclure, Sidney R.; Kimbrough, Andrew G.

    1994-01-01

    This paper wrestles with the on-orbit operational challenges introduced by the proposed Space Construction, Repair, and Maintenance (SCRAM) tool kit for Extra-Vehicular Activity (EVA). SCRAM undertakes a new challenging series of on-orbit tasks in support of the near-term Hubble Space Telescope, Extended Duration Orbiter, Long Duration Orbiter, Space Station Freedom, other orbital platforms, and even the future manned Lunar/Mars missions. These new EVA tasks involve welding, brazing, cutting, coating, heat-treating, and cleaning operations. Anticipated near-term EVA-SCRAM applications include construction of fluid lines and structural members, repair of punctures by orbital debris, refurbishment of surfaces eroded by atomic oxygen, and cleaning of optical, solar panel, and high emissivity radiator surfaces which have been degraded by contaminants. Future EVA-SCRAM applications are also examined, involving mass production tasks automated with robotics and artificial intelligence, for construction of large truss, aerobrake, and reactor shadow shield structures. Realistically achieving EVA-SCRAM is examined by addressing manual, teleoperated, semi-automated, and fully-automated operation modes. The operational challenges posed by EVA-SCRAM tasks are reviewed with respect to capabilities of existing and upcoming EVA systems, such as the Extravehicular Mobility Unit, the Shuttle Remote Manipulating System, the Dexterous End Effector, and the Servicing Aid Tool.

  2. Studies Relating to EVA

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session JA1, the discussion focuses on the following topics: The Staged Decompression to the Hypobaric Atmosphere as a Prophylactic Measure Against Decompression Sickness During Repetitive EVA; A New Preoxygenation Procedure for Extravehicular Activity (EVA); Metabolic Assessments During Extra-Vehicular Activity; Evaluation of Safety of Hypobaric Decompressions and EVA From Positions of Probabilistic Theory; Fatty Acid Composition of Plasma Lipids and Erythrocyte Membranes During Simulation of Extravehicular Activity; Biomedical Studies Relating to Decompression Stress with Simulated EVA, Overview; The Joint Angle and Muscle Signature (JAMS) System - Current Uses and Future Applications; and Experimental Investigation of Cooperative Human-Robotic Roles in an EVA Work Site.

  3. Application of Shuttle EVA Systems to Payloads. Volume 2: Payload EVA Task Completion Plans

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Candidate payload tasks for EVA application were identified and selected, based on an analysis of four representative space shuttle payloads, and typical EVA scenarios with supporting crew timelines and procedures were developed. The EVA preparations and post EVA operations, as well as the timelines emphasizing concurrent payload support functions, were also summarized.

  4. Extravehicular Activity (EVA) 101: Constellation EVA Systems

    NASA Technical Reports Server (NTRS)

    Jordan, Nicole C.

    2007-01-01

    A viewgraph presentation on Extravehicular Activity (EVA) Systems is shown. The topics include: 1) Why do we need space suits? 2) Protection From the Environment; 3) Primary Life Support System (PLSS); 4) Thermal Control; 5) Communications; 6) Helmet and Extravehicular Visor Assy; 7) Hard Upper Torso (HUT) and Arm Assy; 8) Display and Controls Module (DCM); 9) Gloves; 10) Lower Torso Assembly (LTA); 11) What Size Do You Need?; 12) Boot and Sizing Insert; 13) Boot Heel Clip and Foot Restraint; 14) Advanced and Crew Escape Suit; 15) Nominal & Off-Nominal Landing; 16) Gemini Program (mid-1960s); 17) Apollo EVA on Service Module; 18) A Bold Vision for Space Exploration, Authorized by Congress; 19) EVA System Missions; 20) Configurations; 21) Reduced Gravity Program; and 22) Other Opportunities.

  5. Nitroxide-mediated radical ring-opening copolymerization: chain-end investigation and block copolymer synthesis.

    PubMed

    Delplace, Vianney; Harrisson, Simon; Tardy, Antoine; Gigmes, Didier; Guillaneuf, Yohann; Nicolas, Julien

    2014-02-01

    Well-defined, degradable copolymers are successfully prepared by nitroxide-mediated radical ring opening polymerization (NMrROP) of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) or methyl methacrylate (MMA), a small amount of acrylonitrile (AN) and cyclic ketene acetals (CKAs) of different structures. Phosphorous nuclear magnetic resonance allows in-depth chain-end characterization and gives crucial insights into the nature of the copoly-mer terminal sequences and the living chain fractions. By using a small library of P(OEGMA-co-AN-co-CKA) and P(MMA-co-AN-co-CKA) as macroinitiators, chain extensions with styrene are performed to furnish (amphiphilic) block copolymers comprising a degradable segment. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Influence of the association of the EVA and NBR on the characteristics of modified bitumen

    NASA Astrophysics Data System (ADS)

    Bensaada, A.; Soudani, K.; Haddadi, S.; Saoula, S.

    2015-03-01

    Durability and the performance of pavement depend mainly on the characteristics of materials which change over time like all other organic substances. They are subject to significant changes due to environmental conditions during the different phases of use. In the present work we investigated experimentally the influence of the association of ethyl vinyl acetate polymer (EVA) with an industrial waste, acrylonitrile-butadiene rubber (NBR) on the modification of bitumen AC 35-50 and its rheological behavior. The incorporation of NBR and EVA in the bitumen improved its intrinsic characteristics (softening point, penetration and ductility). In addition to improving the characteristics of bituminous binders that will affect the durability of bituminous structures, the environment will be preserved by the recycling of industrial waste.

  7. Cycloolefin/cyanoacrylate (COCA) copolymers for 193-nm and 157-nm lithography

    NASA Astrophysics Data System (ADS)

    Dammel, Ralph R.; Sakamuri, Raj; Lee, Sang-Ho; Rahman, Dalil; Kudo, Takanori; Romano, Andrew R.; Rhodes, Larry F.; Lipian, John-Henry; Hacker, Cheryl; Barnes, Dennis A.

    2002-07-01

    The copolymerization reaction between methyl cyanoacrylate (MCA) and a variety of cycloolefins (CO) was investigated. Cycololefin/cyanoacrylate (COCA) copolymers were obtained in good yields and with lithographically interesting molecular weights for all cycoolefins studied. Anionic MCA homopolymerization could be largely suppressed using acetic acid. Based on NMR data, the copolymerization may tend to a 1:1 CO:MCA incorporation ratio but further work with better suppression of the anionic component is needed to confirm this. Lithographic tests on copolymers of appropriately substituted norbornenes and MCA showed semi-dense and isolated line performance down to 90 nm.

  8. Shuttle EVA description and design criteria

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The STS extravehicular mobility unit, orbiter EVA provisions, EVA equipment, factors affecting employment of EVA, EVA mission integration, baselined extravehicular activity are discussed. Design requirements are also discussed.

  9. EVA design: lessons learned.

    PubMed

    Ross, J L

    1994-01-01

    Extravehicular Activities (EVAs) are very demanding and specialized space flight activities. There are many aspects to consider in the design of hardware, tools, and procedures to be used on an EVA mission. To help minimize costs and optimize the EVA productivity, experience shows that astronauts should become involved early in the design process.

  10. DOE Office of Scientific and Technical Information (OSTI.GOV)

    Holley, W H

    This report describes the results of the literature search, interviews, and site visits conducted during the first six months of this subcontract. This survey was conducted to establish a baseline of information about thermal and photothermal degradation of EVA and case history surveys on discoloration (yellowing/browning) of EVA-based encapsulants in fielded flat-plate PV modules. The literature search revealed that EVA will undergo thermolysis of the acetate groups at temperatures of 130{degrees}C to 150{degrees}C and above, leading to formation of double bonds in the backbone of the copolymer. The survey of case histories of EVA-based encapsulant discoloration in fielded modules inmore » the United States revealed that the problem is limited to those areas of the west and southwest that have comparatively high solar insolation and ambient temperature. It is clear that the discoloration problem is not limited to the modules of any one manufacturer. Discoloration in the EVA encapsulant was experienced in fielded modules from all major US module producers.« less

  11. Post-Shuttle EVA Operations on ISS

    NASA Technical Reports Server (NTRS)

    West, William; Witt, Vincent; Chullen, Cinda

    2010-01-01

    The expected retirement of the NASA Space Transportation System (also known as the Space Shuttle ) by 2011 will pose a significant challenge to Extra-Vehicular Activities (EVA) on-board the International Space Station (ISS). The EVA hardware currently used to assemble and maintain the ISS was designed assuming that it would be returned to Earth on the Space Shuttle for refurbishment, or if necessary for failure investigation. With the retirement of the Space Shuttle, a new concept of operations was developed to enable EVA hardware (Extra-vehicular Mobility Unit (EMU), Airlock Systems, EVA tools, and associated support hardware and consumables) to perform ISS EVAs until 2015, and possibly beyond to 2020. Shortly after the decision to retire the Space Shuttle was announced, the EVA 2010 Project was jointly initiated by NASA and the One EVA contractor team. The challenges addressed were to extend the operating life and certification of EVA hardware, to secure the capability to launch EVA hardware safely on alternate launch vehicles, to protect for EMU hardware operability on-orbit, and to determine the source of high water purity to support recharge of PLSSs (no longer available via Shuttle). EVA 2010 Project includes the following tasks: the development of a launch fixture that would allow the EMU Portable Life Support System (PLSS) to be launched on-board alternate vehicles; extension of the EMU hardware maintenance interval from 3 years (current certification) to a minimum of 6 years (to extend to 2015); testing of recycled ISS Water Processor Assembly (WPA) water for use in the EMU cooling system in lieu of water resupplied by International Partner (IP) vehicles; development of techniques to remove & replace critical components in the PLSS on-orbit (not routine); extension of on-orbit certification of EVA tools; and development of an EVA hardware logistical plan to support the ISS without the Space Shuttle. Assumptions for the EVA 2010 Project included no more

  12. EVA Training and Development Facilities

    NASA Technical Reports Server (NTRS)

    Cupples, Scott

    2016-01-01

    Overview: Vast majority of US EVA (ExtraVehicular Activity) training and EVA hardware development occurs at JSC; EVA training facilities used to develop and refine procedures and improve skills; EVA hardware development facilities test hardware to evaluate performance and certify requirement compliance; Environmental chambers enable testing of hardware from as large as suits to as small as individual components in thermal vacuum conditions.

  13. Post-Shuttle EVA Operations on ISS

    NASA Technical Reports Server (NTRS)

    West, Bill; Witt, Vincent; Chullen, Cinda

    2010-01-01

    The EVA hardware used to assemble and maintain the ISS was designed with the assumption that it would be returned to Earth on the Space Shuttle for ground processing, refurbishment, or failure investigation (if necessary). With the retirement of the Space Shuttle, a new concept of operations was developed to enable EVA hardware (EMU, Airlock Systems, EVA tools, and associated support equipment and consumables) to perform ISS EVAs until 2016 and possibly beyond to 2020. Shortly after the decision to retire the Space Shuttle was announced, NASA and the One EVA contractor team jointly initiated the EVA 2010 Project. Challenges were addressed to extend the operating life and certification of EVA hardware, secure the capability to launch EVA hardware safely on alternate launch vehicles, and protect EMU hardware operability on orbit for long durations.

  14. Application of shuttle EVA systems to payloads. Volume 1: EVA systems and operational modes description

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Descriptions of the EVA system baselined for the space shuttle program were provided, as well as a compendium of data on available EVA operational modes for payload and orbiter servicing. Operational concepts and techniques to accomplish representative EVA payload tasks are proposed. Some of the subjects discussed include: extravehicular mobility unit, remote manipulator system, airlock, EVA translation aids, restraints, workstations, tools and support equipment.

  15. Advanced EVA system design requirements study

    NASA Technical Reports Server (NTRS)

    Woods, T. G.

    1988-01-01

    The results are presented of a study to identify specific criteria regarding space station extravehicular activity system (EVAS) hardware requirements. Key EVA design issues include maintainability, technology readiness, LSS volume vs. EVA time available, suit pressure/cabin pressure relationship and productivity effects, crew autonomy, integration of EVA as a program resource, and standardization of task interfaces. A variety of DOD EVA systems issues were taken into consideration. Recommendations include: (1) crew limitations, not hardware limitations; (2) capability to perform all of 15 generic missions; (3) 90 days on-orbit maintainability with 50 percent duty cycle as minimum; and (4) use by payload sponsors of JSC document 10615A plus a Generic Tool Kit and Specialized Tool Kit description. EVA baseline design requirements and criteria, including requirements of various subsystems, are outlined. Space station/EVA system interface requirements and EVA accommodations are discussed in the areas of atmosphere composition and pressure, communications, data management, logistics, safe haven, SS exterior and interior requirements, and SS airlock.

  16. PLGA-PEG-PLGA hydrogel for ocular drug delivery of dexamethasone acetate.

    PubMed

    Gao, Yuan; Sun, Yan; Ren, Fuzheng; Gao, Shen

    2010-10-01

    This study aims to investigate the suitability of thermosensitive triblock polymer poly-(DL-lactic acid-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA as a matrix material for ocular delivery of dexamethasone acetate (DXA). The copolymer was synthesized and evaluated for its thermosensitive and gelation properties. DXA in situ gel-forming solution based on PLGA-PEG-PLGA copolymer of 20% (w/w) was prepared and evaluated for ocular pharmacokinetics in rabbit according to the microdialysis method, which was compared to the normal eye drop. The copolymer with 20% (w/w) had a low critical solution temperature of 32 degrees C, which is close to the surface temperature of the eye. The C(max) of DXA in the anterior chamber for the PLGA-PEG-PLGA solution was 125.2 microg/mL, which is sevenfold higher than that of the eye drop, along with greater area under the concentration-time curves (AUC). These results suggest that the PLGA-PEG-PLGA copolymer is potential thermosensitive in situ gel-forming material for ocular drug delivery, and it may improve the bioavailability, efficacy of some eye drugs.

  17. In-situ Polymerization of Polyaniline/Polypyrrole Copolymer using Different Techniques

    NASA Astrophysics Data System (ADS)

    Hammad, A. S.; Noby, H.; Elkady, M. F.; El-Shazly, A. H.

    2018-01-01

    The morphology and surface area of the poly(aniline-co-pyrrole) copolymer (PANPY) are important properties which improve the efficiency of the copolymer in various applications. In this investigation, different techniques were employed to produce PANPY in different morphologies. Aniline and pyrrole were used as monomers, and ammonium peroxydisulfate (APS) was used as an oxidizer with uniform molar ratio. Rapid mixing, drop-wise mixing, and supercritical carbon dioxide (ScCO2) polymerization techniques were appointed. The chemical structure, crystallinity, porosity, and morphology of the composite were distinguished by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer, Emmett and Teller (BET) analysis, and transmission electron microscopy (TEM) respectively. The characterization tests indicated that the polyaniline/polypyrrole copolymer was successfully prepared with different morphologies. Based on the obtained TEM, hollow nanospheres were formed using rapid mixing technique with acetic acid that have a diameter of 75 nm and thickness 26 nm approximately. Also, according to the XRD, the produced structures have a semi- crystalline structure. The synthesized copolymer with ScCO2-assisted polymerization technique showed improved surface area (38.1 m2/g) with HCl as dopant.

  18. EVA Systems Technology Gaps and Priorities 2017

    NASA Technical Reports Server (NTRS)

    Johnson, Brian J.; Buffington, Jesse A.

    2017-01-01

    Performance of Extra-Vehicular Activities (EVA) has been and will continue to be a critical capability for human space flight. Human exploration missions beyond LEO will require EVA capability for either contingency or nominal activities to support mission objectives and reduce mission risk. EVA systems encompass a wide array of products across pressure suits, life support systems, EVA tools and unique spacecraft interface hardware (i.e. EVA Translation Paths and EVA Worksites). In a fiscally limited environment with evolving transportation and habitation options, it is paramount that the EVA community's strategic planning and architecture integration products be reviewed and vetted for traceability between the mission needs far into the future to the known technology and knowledge gaps to the current investments across EVA systems. To ascertain EVA technology and knowledge gaps many things need to be brought together, assessed and analyzed. This includes an understanding of the destination environments, various mission concept of operations, current state of the art of EVA systems, EVA operational lessons learned, and reference advanced capabilities. A combined assessment of these inputs should result in well-defined list of gaps. This list can then be prioritized depending on the mission need dates and time scale of the technology or knowledge gap closure plan. This paper will summarize the current state of EVA related technology and knowledge gaps derived from NASA's Exploration EVA Reference Architecture and Operations Concept products. By linking these products and articulating NASA's approach to strategic development for EVA across all credible destinations an EVA could be done in, the identification of these gaps is then used to illustrate the tactical and strategic planning for the EVA technology development portfolio. Finally, this paper illustrates the various "touch points" with other human exploration risk identification areas including human health and

  19. EVA Skills Training

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott

    2012-01-01

    Dr. Parazynski and a colleague from Extravehicular Activity (EVA), Robotics, & Crew Systems Operations (DX) worked closely to build the EVA Skills Training Program, and for the first time, defined the gold standards of EVA performance, allowing crewmembers to increase their performance significantly. As part of the program, individuals had the opportunity to learn at their own rate, taking additional water time as required, to achieve that level of performance. This focus on training to one's strengths and weaknesses to bolster them enabled the Crew Office and DX to field a much larger group of spacewalkers for the daunting "wall of EVA" required for the building and maintenance of the ISS. Parazynski also stressed the need for designers to understand the capabilities and the limitations of a human in a spacesuit, as well as opportunities to improve future generations of space. He shared lessons learned (how the Crew Office engaged in these endeavors) and illustrated the need to work as a team to develop these complex systems.

  20. Fogging Control on LDPE/EVA Coextruded Films: Wettability Behavior and Its Correlation with Electric Performance.

    PubMed

    Waldo-Mendoza, Miguel A; Quiñones-Jurado, Zoe V; Pérez-Medina, Juan C; Yañez-Soto, Bernardo; Ramírez-González, Pedro E

    2017-02-22

    The transformation of fog at a non-visible water layer on a membrane of low-density polyethylene (LDPE) and ethylene-vinyl acetate (EVA) was evaluated. Nonionic surfactants of major demand in the polyolefin industry were studied. A kinetic study using a hot fog chamber showed that condensation is controlled by both the diffusion and permanency of the surfactant more than by the change of the surface energy developed by the wetting agents. The greatest permanency of the anti-fog effect of the LDPE/EVA surface was close to 3000 h. The contact angle results demonstrated the ability of the wetting agent to spread out to the surface. Complementarily, the migration of nonionic surfactants from the inside of the polymeric matrix to the surface was analyzed by Fourier transform infrared (FTIR) microscopy. Additionally, electrical measurement on the anti-fogging membrane at alternating currents and at a sweep frequency was proposed to test the conductivity and wetting ability of nonionic surfactants. We proved that the amphiphilic molecules had the ability to increase the conductivity in the polyolefin membrane. A correlation between the bulk electrical conductivity and the permanency of the fogging control on the LDPE/EVA coextruded film was found.

  1. Effect of oxidation agent on wood biomass in ethylene vinyl acetate conductive polymer: tensile properties, tensile fracture surface and electrical properties

    NASA Astrophysics Data System (ADS)

    Hanif, M. P. M.; Supri, A. G.; Rozyanty, A. R.; Tan, S. J.

    2017-10-01

    The wood fiber (WF) type of Pulverised Wood Filler obtained by combustion process at temperature under 700 °C for 3 hours was characterized and coated with ferric chloride (FeCl3) by ethanol solution. Both carbonized wood fiber (CWF) and carbonized wood fiber-ferric chloride (CWF-FeCl3) were used as filler in ethylene vinyl acetate (EVA) conductive polymer. The filler was coated with FeCl3 to enhance the properties of the CWF to achieve progressive mechanical and electrical properties. The CWF and CWF-FeCl3 loading were varied from 2.5 to 10.0 wt%. EVA/CWF and EVA/CWF-FeCl3 conductive polymer were processed by using Brabender Plasticoder at 160 °C with 50 rpm rotor speed for 10 min. The mechanical properties were investigated by tensile testing and the tensile fractured surface of conductive polymers was analyzed by scanning electron microscopy (SEM) analysis. Then, the electrical conductivity of conductive polymer was determined by four-point probe I-V measurement system. The EVA/CWF-FeCl3 conductive polymer showed greater electrical conductivity and tensile strength but lower elongation at break than EVA/CWF conductive polymer. SEM morphology displayed rougher surface between CWF-FeCl3 and EVA phases compared to EVA/CWF conductive polymer.

  2. Ethylene vinyl acetate based radiation grafted hydrophilic matrices: Process parameter standardization, grafting kinetics and characterization

    NASA Astrophysics Data System (ADS)

    Chaudhari, C. V.; Mondal, R. K.; Dubey, K. A.; Grover, V.; Panicker, L.; Bhardwaj, Y. K.; Varshney, L.

    2016-08-01

    A transparent, elastomeric, grafted matrix for several potential applications was synthesized by single-step simultaneous radiation grafting of methacrylic acid onto ethylene vinyl acetate (EVA). CuSO4 was found to be the most suitable homo-polymerization inhibitor among different inhibitors tried. The grafting kinetics was found to be a strong function of dose rate (D) and monomer content (M) and an equation relating grafting rate Rg=Kg [M]1.13D0.23 was deduced. Crystallinity of the grafted matrices as assessed from XRD and DSC measurements indicated decrease in crystalline content with increase in grafting yield, suggesting crystalline domain of EVA get disrupted on grafting. Elastic modulus increased linearly with the increase in grafting yield, though elongation at break decreased precipitously from 900% to 30% at even 9% grafting. Thermo-gravimetric analysis showed three step weight loss of the grafted EVA matrix. The grafting of MAA resulted in increase in surface energy mainly due to enhanced polar component.

  3. EVA safety: Space suit system interoperability

    NASA Technical Reports Server (NTRS)

    Skoog, A. I.; McBarron, J. W.; Abramov, L. P.; Zvezda, A. O.

    1995-01-01

    The results and the recommendations of the International Academy of Astronautics extravehicular activities (IAA EVA) Committee work are presented. The IAA EVA protocols and operation were analyzed for harmonization procedures and for the standardization of safety critical and operationally important interfaces. The key role of EVA and how to improve the situation based on the identified EVA space suit system interoperability deficiencies were considered.

  4. Antifouling Thermoplastic Composites with Maleimide Encapsulated in Clay Nanotubes.

    PubMed

    Fu, Ye; Gong, Congcong; Wang, Wencai; Zhang, Liqun; Ivanov, Evgenii; Lvov, Yuri

    2017-09-06

    An antifouling ethylene-vinyl acetate copolymer (EVA) coating with halloysite clay nanotubes loaded with maleimide (TCPM) is prepared. Such antifoulant encapsulation allowed for extended release of TCPM and a long-lasting, efficient protection of the coated surface against marine microorganisms proliferation. Halloysite also induces the composite's anisotropy due to parallel alignment of the nanotubes. The maleimide loaded halloysite incorporated into the polymer matrix allowed for 12-month release of the bacterial inhibitor preventing fouling; it is much longer than the 2-3 month protection when TCPM is directly admixed into EVA. The antifouling properties of the EVA-halloysite nanocomposites were tested by monitoring surface adhesion and proliferation of marine V. natriegens bacteria with SEM. As compared to the composite directly doped with TCPM-antifoulant, there were much less bacteria accumulated on the EVA-halloysite-TCPM coating after a 2-month exposure to seawater. Field tests at South China Sea marine station further confirmed the formulation efficiency. The doping of 28 wt % TCPM loaded halloysite drastically enhanced material antifouling property, which promises wide applications for protective marine coating.

  5. Comb-like amphiphilic copolymers bearing acetal-functionalized backbones with the ability of acid-triggered hydrophobic-to-hydrophilic transition as effective nanocarriers for intracellular release of curcumin.

    PubMed

    Zhao, Junqiang; Wang, Haiyang; Liu, Jinjian; Deng, Liandong; Liu, Jianfeng; Dong, Anjie; Zhang, Jianhua

    2013-11-11

    The pH-responsive micelles have enormous potential as nanosized drug carriers for cancer therapy due to their physicochemical changes in response to the tumor intracellular acidic microenvironment. Herein, a series of comb-like amphiphilic copolymers bearing acetal-functionalized backbone were developed based on poly[(2,4,6-trimethoxybenzylidene-1,1,1-tris(hydroxymethyl) ethane methacrylate-co-poly(ethylene glycol) methyl ether methacrylate] [P(TTMA-co-mPEGMA)] as effective nanocarriers for intracellular curcumin (CUR) release. P(TTMA-co-mPEGMA) copolymers with different hydrophobic-hydrophilic ratios were prepared by one-step reversible addition fragmentation chain transfer (RAFT) copolymerization of TTMA and mPEGMA. Their molecular structures and chemical compositions were confirmed by (1)H NMR, Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). P(TTMA-co-mPEGMA) copolymers could self-assemble into nanosized micelles in aqueous solution and displayed low critical micelle concentration (CMC). All P(TTMA-co-mPEGMA) micelles displayed excellent drug loading capacity, due to the strong π-π conjugate action and hydrophobic interaction between the PTTMA and CUR. Moreover, the hydrophobic PTTMA chain could be selectively hydrolyzed into a hydrophilic backbone in the mildly acidic environment, leading to significant swelling and final disassembly of the micelles. These morphological changes of P(TTMA-co-mPEGMA) micelles with time at pH 5.0 were determined by DLS and TEM. The in vitro CUR release from the micelles exhibited a pH-dependent behavior. The release rate of CUR was significantly accelerated at mildly acidic pH of 4.0 and 5.0 compared to that at pH 7.4. Toxicity test revealed that the P(TTMA-co-mPEGMA) copolymers exhibited low cytotoxicity, whereas the CUR-loaded micelles maintained high cytotoxicity for HepG-2 and EC-109 cells. The results indicated that the novel P(TTMA-co-mPEGMA) micelles with low CMC, small and tunable

  6. Walking to Olympus: An EVA Chronology

    NASA Technical Reports Server (NTRS)

    Portree, David S. F.; Trevino, Robert C.

    1997-01-01

    Spacewalkers enjoy a view of Earth once reserved for Apollo, Zeus, and other denizens of Mt. Olympus. During humanity's first extravehicular activity (EVA), Alexei Leonov floated above Gibraltar, the rock ancient seafarers saw as the gateway to the great unknown Atlantic. The symbolism was clear, Leonov stepped past a new Gibraltar when he stepped into space. More than 32 years and 154 EVAs later, Jerry Linenger conducted an EVA with Vladimir Tsibliyev as part of International Space Station Phase 1. They floated together above Gibraltar. Today the symbolism has new meaning: humanity is starting to think of stepping out of Earth orbit, space travel's new Gibraltar, and perhaps obtaining a new olympian view, a close-up look at Olympus Mons on Mars. Walking to Olympus: An EVA Chronology chronicles the 154 EVAs conducted from March 1965 to April 1997. It is intended to make clear the crucial role played by EVA in the history of spaceflight, as well as to chronicle the large body of EVA "lessons learned." Russia and the U.S. define EVA differently. Russian cosmonauts are said to perform EVA any time they are in vacuum in a space suit. A U.S. astronaut must have at least his head outside his spacecraft before he is said to perform an EVA. The difference is based in differing spacecraft design philoso- phies. Russian and Soviet spacecraft have always had a specialized airlock through which the EVA cosmonaut egressed, leaving the main habitable volume of the spacecraft pressurized. The U.S. Gemini and Apollo vehicles, on the other hand, depressurized their entire habitable volume for egress. In this document, we apply the Russian definition to Russian EVAS, and the U.S. definition to U.S. EVAS. Thus, for example, Gemini 4 Command Pilot James McDivitt does not share the honor of being first American spacewalker with Ed White, even though he was suited and in vacuum when White stepped out into space. Non-EVA spaceflights are listed in the chronology to provide context and to

  7. Space shuttle EVA opportunities. [a technology assessment

    NASA Technical Reports Server (NTRS)

    Bland, D. A., Jr.

    1976-01-01

    A technology assessment is presented on space extravehicular activities (EVA) that will be possible when the space shuttle orbiter is completed and launched. The use of EVA in payload systems design is discussed. Also discussed is space crew training. The role of EVA in connection with the Large Space Telescope and Skylab are described. The value of EVA in constructing structures in space and orbital assembly is examined. Excellent color illustrations are provided which show the proposed EVA functions that were described.

  8. Real-Time EVA Troubleshooting

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott

    2012-01-01

    Dr. Parazynski focused on the Shuttle Transportation System (STS)-120 Solar Array Repair Extravehicular Activity (EVA) with personal anecdotes and then spoke about what it takes to have a successful EVA during the event, what types of problems can occur during an EVA, particularly with the spacesuit and the safety of the crew, and how to resolve these quickly, safely, and efficiently. He also described the participants and the types of decisions and actions each had to take to ensure success. He described "Team 4," in Houston and on-orbit, as well as anecdotes from his STS-86 and STS-100 missions. Parazynski provided a retrospective on the EVA tools and procedures NASA used in the aftermath of Columbia for shuttle Thermal Protection System (TPS) inspection and repair. He described his role as the lead astronaut during this effort, and covered all the Neutral Buoyancy Laboratory (NBL), KC-135, precision air-bearing floor (PABF), vacuum chamber, and 1-G testing performed to develop the tools and techniques that were flown. Parazynski discussed how the EVA community worked together to resolve a huge safety issue, and how his work in the spacesuit was critical to overcoming a design limitation of the Space Shuttle.

  9. Numerical-experimental investigation of PE/EVA foam injection molded parts

    NASA Astrophysics Data System (ADS)

    Spina, Roberto

    The main objective of the presented work is to propose a robust framework to test foaming injection molded parts, with the aim of establishing a standard testing cycle for the evaluation of a new foam material based on numerical and experimental results. The research purpose is to assess parameters influencing several aspects, such as foam morphology and compression behavior, using useful suggestions from finite element analysis. The investigated polymeric blend consisted of a mixture of low density polyethylenes (LDPEs), a high-density polyethylene (HDPE), an ethylene-vinyl acetate (EVA) and an azodicarbonamide (ADC). The thermal, rheological and compression properties of the blend are fully described, as well as the numerical models and the parameters of the injection molding process.

  10. Fogging Control on LDPE/EVA Coextruded Films: Wettability Behavior and Its Correlation with Electric Performance

    PubMed Central

    Waldo-Mendoza, Miguel A.; Quiñones-Jurado, Zoe V.; Pérez-Medina, Juan C.; Yañez-Soto, Bernardo; Ramírez-González, Pedro E.

    2017-01-01

    The transformation of fog at a non-visible water layer on a membrane of low-density polyethylene (LDPE) and ethylene-vinyl acetate (EVA) was evaluated. Nonionic surfactants of major demand in the polyolefin industry were studied. A kinetic study using a hot fog chamber showed that condensation is controlled by both the diffusion and permanency of the surfactant more than by the change of the surface energy developed by the wetting agents. The greatest permanency of the anti-fog effect of the LDPE/EVA surface was close to 3000 h. The contact angle results demonstrated the ability of the wetting agent to spread out to the surface. Complementarily, the migration of nonionic surfactants from the inside of the polymeric matrix to the surface was analyzed by Fourier transform infrared (FTIR) microscopy. Additionally, electrical measurement on the anti-fogging membrane at alternating currents and at a sweep frequency was proposed to test the conductivity and wetting ability of nonionic surfactants. We proved that the amphiphilic molecules had the ability to increase the conductivity in the polyolefin membrane. A correlation between the bulk electrical conductivity and the permanency of the fogging control on the LDPE/EVA coextruded film was found. PMID:28241433

  11. Surface functionalization of carbon nanotubes by direct encapsulation with varying dosages of amphiphilic block copolymers

    NASA Astrophysics Data System (ADS)

    Yao, Xueping; Li, Jie; Kong, Liang; Wang, Yong

    2015-08-01

    Encapsulation of carbon nanotubes (CNTs) by amphiphilic block copolymers is an efficient way to stabilize CNTs in solvents. However, the appropriate dosages of copolymers and the assembled structures are difficult to predict and control because of the insufficient understanding on the encapsulation process. We encapsulate multiwalled CNTs with polystyrene-block-poly (4-vinyl pyridine) (PS-b-P4VP) by directly mixing them in acetic acid under sonication. The copolymer forms a lamellar structure along the surface of CNTs with the PS blocks anchoring on the tube wall and the P4VP blocks exposed to the outside. The encapsulated CNTs achieve good dispersibility in polar solvents over long periods. To increase our understanding of the encapsulation process we investigate the assembled structures and stability of copolymer/CNTs mixtures with changing mass ratios. Stable dispersions are obtained at high mass ratios between the copolymer and CNTs, i.e. 2 or 3, with the presence of free spherical micelles. Transmission electron microscopy and thermal gravimetric analysis determine that the threshold for the complete coverage of CNTs by the copolymer occurs at the mass ratio of 1.5. The coated copolymer layer activates the surface of CNTs, enabling further functionalization of CNTs. For instance, atomic layer deposition of TiO2 produces conformal thin layers on the encapsulated CNTs while isolated TiO2 bumps are produced on the pristine, inert CNTs.

  12. EVA dosimetry in manned spacecraft.

    PubMed

    Thomson, I

    1999-12-06

    Extra Vehicular Activity (EVA) will become a large part of the astronaut's work on board the International Space Station (ISS). It is already well known that long duration space missions inside a spacecraft lead to radiation doses which are high enough to be a significant health risk to the crew. The doses received during EVA, however, have not been quantified to the same degree. This paper reviews the space radiation environment and the current dose limits to critical organs. Results of preliminary radiation dosimetry experiments on the external surface of the BION series of satellites indicate that EVA doses will vary considerably due to a number of factors such as EVA suit shielding, temporal fluctuations and spacecraft orbit and shielding. It is concluded that measurement of doses to crew members who engage in EVA should be done on board the spacecraft. An experiment is described which will lead the way to implementing this plan on the ISS. It is expected that results of this experiment will help future crew mitigate the risks of ionising radiation in space.

  13. Advanced EVA system design requirements study

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Design requirements and criteria for the Space Station Advanced Extravehicular Activity System (EVAS) including crew enclosures, portable life support systems, maneuvering propulsion systems, and related extravehicular activity (EVA) support equipment were defined and established. The EVA mission requirements, environments, and medical and physiological requirements, as well as opertional, procedures, and training issues were considered.

  14. One hundred US EVAs: a perspective on spacewalks.

    PubMed

    Wilde, Richard C; McBarron, James W; Manatt, Scott A; McMann, Harold J; Fullerton, Richard K

    2002-01-01

    In the 36 years between June 1965 and February 2001, the US human space flight program has conducted 100 spacewalks, or extravehicular activities (EVAs), as NASA officially calls them. EVA occurs when astronauts wearing spacesuits travel outside their protective spacecraft to perform tasks in the space vacuum environment. US EVA started with pioneering feasibility tests during the Gemini Program. The Apollo Program required sending astronauts to the moon and performing EVA to explore the lunar surface. EVA supported scientific mission objectives of the Skylab program, but may be best remembered for repairing launch damage to the vehicle and thus saving the program. EVA capability on Shuttle was initially planned to be a kit that could be flown at will, and was primarily intended for coping with vehicle return emergencies. The Skylab emergency and the pivotal role of EVA in salvaging that program quickly promoted Shuttle EVA to an essential element for achieving mission objectives, including retrieving satellites and developing techniques to assemble and maintain the International Space Station (ISS). Now, EVA is supporting assembly of ISS. This paper highlights development of US EVA capability within the context of the overarching mission objectives of the US human space flight program. c2002 International Astronautical Federation. Published by Elsevier Science Ltd. All rights reserved.

  15. The effects of 60Co γ-ray on poly(ethylene-co-vinyl acetate)/carbon black composites

    NASA Astrophysics Data System (ADS)

    Lee, Kyoung-Yong; Kim, Ki-Yup

    2008-04-01

    Cables used in a nuclear power plant are irradiation suppressing ones. Until now, researches on the irradiation suppressing cables have mainly been focused on insulation materials. Therefore, in this paper, the non-isothermal crystallization behaviors and degradation characteristics of ethylene vinyl acetate-carbon black (EVA-CB), used as a shielding material, were investigated by means of the Differential scanning calorimetry (DSC) and chemiluminescence analyzer (CL). The specimens were cooled after removing thermal history at 150 °C for 5 min by changing the cooling rates to 5, 7.5, 10, 15 and 20 °C/min with DSC. In addition, after maintaining a thermal equilibrium at each temperature of 25, 50, 75, 100, 125, 150 and 175 °C, their thermoluminescence was measured for 20 min with CL equipment. The 60Co γ-ray was used for irradiation. Tc, T0, T∞ and t1/2 in the DSC experiments are found to decrease gradually as radiation dose increases. Secondly, with the CL experiment, the 0.1, 0.25 and 0.5 MGy EVA-CB composites were found to show a much smaller thermoluminescence than the intact EVA-CB composites, while the 0.75 and 1 MGy EVA-CB composites were found to show a much higher thermoluminescence than ones.

  16. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028082 (9 Nov. 2013) --- Russian cosmonaut Sergey Ryazanskiy, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Ryazanskiy and Russian cosmonaut Oleg Kotov (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  17. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028067 (9 Nov. 2013) --- Russian cosmonaut Oleg Kotov, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Russian cosmonaut Sergey Ryazanskiy (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  18. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028101 (9 Nov. 2013) --- Russian cosmonaut Oleg Kotov, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Russian cosmonaut Sergey Ryazanskiy (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  19. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028094 (9 Nov. 2013) --- Russian cosmonaut Oleg Kotov, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Russian cosmonaut Sergey Ryazanskiy (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  20. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028107 (9 Nov. 2013) --- Russian cosmonaut Oleg Kotov, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Russian cosmonaut Sergey Ryazanskiy (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  1. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028102 (9 Nov. 2013) --- Russian cosmonaut Oleg Kotov, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Russian cosmonaut Sergey Ryazanskiy (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  2. Aging Studies of VCE Dismantlement Returns

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Letant, S; Alviso, C; Pearson, M

    2011-10-17

    VCE is an ethylene/vinyl acetate/vinyl alcohol terpolymer binder for filled elastomers which is designed to accept high filler loadings. Filled elastomer parts consist of the binder (VCE), a curing agent (Hylene MP, diphenol-4-4{prime}-methylenebis(phenylcarbamate)), a processing aid (LS, lithium stearate), and filler particles (typically 70% fraction by weight). The curing of the filled elastomer parts occurs from the heat-activated reaction between the hydroxyl groups of VCE with the Hylene MP curing agent, resulting in a cross-linked network. The final vinyl acetate content is typically between 34.9 and 37.9%, while the vinyl alcohol content is typically between 1.27 and 1.78%. Surveillance datamore » for this material is both scarce and scattered, complicating the assessment of any aging trends in systems. In addition, most of the initial surveillance efforts focused on mechanical properties such as hardness and tensile strength, and chemical information is therefore lacking. Material characterization and aging studies had been performed on previous formulations of the VCE material but the Ethylene Vinyl Acetate (EVA) starting copolymer is no longer commercially available. New formulations with replacement EVA materials are currently being established and will require characterization as well as updated aging models.« less

  3. Russian EVA 36

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028569 (9 Nov. 2013) --- Russian cosmonaut Oleg Kotov, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, uses a still camera during a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Russian cosmonaut Sergey Ryazanskiy (out of frame) continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  4. Investigation of compression behavior of PE/EVA foam injection molded parts

    NASA Astrophysics Data System (ADS)

    Spina, Roberto

    2017-10-01

    The main objective of the presented work is to evaluate the compression behavior of a polymeric foam blend by using a robust framework for the testing sequence of foaming injection molded parts, with the aim of establishing a standard testing cycle for the evaluation of new matrix material. The research purpose is to assess parameters influencing compression behavior and give useful suggestions for the implementation of a finite element analysis. The polymeric blend consisted of a mixture of low density polyethylenes (LDPEs), a high-density polyethylene (HDPE), an ethylene-vinyl acetate (EVA) and an azodicarbonamide (ADC). The thermal, rheological and compression properties of the blend are fully described, as well as the injection molding process for two specimen types.

  5. EVA 4 - Massimino during EVA

    NASA Image and Video Library

    2002-03-07

    STS109-323-013 (7 March 2002) --- Astronaut Michael J. Massimino moves about in the cargo bay of the Space Shuttle Columbia while performing work on the Hubble Space Telescope (HST), partially visible behind him. Astronauts Massimino and James H. Newman (out of frame), mission specialists, were participating in the fourth STS-109 space walk (EVA-4).

  6. Extravehicular Activity (EVA) Technology Development Status and Forecast

    NASA Technical Reports Server (NTRS)

    Chullen, Cinda; Westheimer, David T.

    2010-01-01

    Beginning in Fiscal Year (FY) 2011, Extravehicular activity (EVA) technology development became a technology foundational domain under a new program Enabling Technology Development and Demonstration. The goal of the EVA technology effort is to further develop technologies that will be used to demonstrate a robust EVA system that has application for a variety of future missions including microgravity and surface EVA. Overall the objectives will be reduce system mass, reduce consumables and maintenance, increase EVA hardware robustness and life, increase crew member efficiency and autonomy, and enable rapid vehicle egress and ingress. Over the past several years, NASA realized a tremendous increase in EVA system development as part of the Exploration Technology Development Program and the Constellation Program. The evident demand for efficient and reliable EVA technologies, particularly regenerable technologies was apparent under these former programs and will continue to be needed as future mission opportunities arise. The technological need for EVA in space has been realized over the last several decades by the Gemini, Apollo, Skylab, Space Shuttle, and the International Space Station (ISS) programs. EVAs were critical to the success of these programs. Now with the ISS extension to 2028 in conjunction with a current forecasted need of at least eight EVAs per year, the EVA technology life and limited availability of the EMUs will become a critical issue eventually. The current Extravehicular Mobility Unit (EMU) has vastly served EVA demands by performing critical operations to assemble the ISS and provide repairs of satellites such as the Hubble Space Telescope. However, as the life of ISS and the vision for future mission opportunities are realized, a new EVA systems capability could be an option for the future mission applications building off of the technology development over the last several years. Besides ISS, potential mission applications include EVAs for

  7. Go for EVA!

    NASA Technical Reports Server (NTRS)

    1995-01-01

    In this educational video series, 'Liftoff to Learning', astronauts from the STS-37 Space Shuttle Mission (Jay Apt, Jerry Ross, Ken Cameron, Steve Nagel, and Linda Godwin) show what EVA (extravehicular activity) means, talk about the history and design of the space suits and why they are designed the way they are, describe different ways they are used (payload work, testing and maintenance of equipment, space environment experiments) in EVA work, and briefly discuss the future applications of the space suits. Computer graphics and animation is included.

  8. Phillips during EVA

    NASA Image and Video Library

    2005-08-18

    ISS011-E-11958 (18 August 2005) --- Attired in a Russian Orlan spacesuit, astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, participates in a session of extravehicular activity (EVA). The 4 hour 58 minute spacewalk by Phillips and cosmonaut Sergei K. Krikalev (out of frame), commander representing Russia's Federal Space Agency, was the 62nd EVA in support of Station assembly and maintenance, the 34th conducted from the Station itself, and the 16th from the Pirs Docking Compartment.

  9. Phillips during EVA

    NASA Image and Video Library

    2005-08-18

    ISS011-E-11944 (18 August 2005) --- Attired in a Russian Orlan spacesuit, astronaut John L. Phillips, Expedition 11 NASA science officer and flight engineer, participates in a session of extravehicular activity (EVA). The 4 hour 58 minute spacewalk by Phillips and cosmonaut Sergei K. Krikalev (out of frame), commander representing Russia's Federal Space Agency, was the 62nd EVA in support of station assembly and maintenance, the 34th conducted from the station itself, and the 16th from the Pirs Docking Compartment.

  10. EVA Physiology and Medical Considerations Working in the Suit

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott

    2012-01-01

    This "EVA Physiology and Medical Considerations Working in the Suit" presentation covers several topics related to the medical implications and physiological effects of suited operations in space from the perspective of a physician with considerable first-hand Extravehicular Activity (EVA) experience. Key themes include EVA physiology working in a pressure suit in the vacuum of space, basic EVA life support and work support, Thermal Protection System (TPS) inspections and repairs, and discussions of the physical challenges of an EVA. Parazynski covers the common injuries and significant risks during EVAs, as well as physical training required to prepare for EVAs. He also shares overall suit physiological and medical knowledge with the next generation of Extravehicular Mobility Unit (EMU) system designers.

  11. Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT)

    NASA Technical Reports Server (NTRS)

    Brown, Cheryl B.; Conger, Bruce C.; Miranda, Bruno M.; Bue, Grant C.; Rouen, Michael N.

    2007-01-01

    An effort was initiated by NASA/JSC in 2001 to develop an Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT) for the sizing of Extravehicular Activity System (EVAS) architecture and studies. Its intent was to support space suit development efforts and to aid in conceptual designs for future human exploration missions. Its basis was the Life Support Options Performance Program (LSOPP), a spacesuit and portable life support system (PLSS) sizing program developed for NASA/JSC circa 1990. EVAS_SAT estimates the mass, power, and volume characteristics for user-defined EVAS architectures, including Suit Systems, Airlock Systems, Tools and Translation Aids, and Vehicle Support equipment. The tool has undergone annual changes and has been updated as new data have become available. Certain sizing algorithms have been developed based on industry standards, while others are based on the LSOPP sizing routines. The sizing algorithms used by EVAS_SAT are preliminary. Because EVAS_SAT was designed for use by members of the EVA community, subsystem familiarity on the part of the intended user group and in the analysis of results is assumed. The current EVAS_SAT is operated within Microsoft Excel 2003 using a Visual Basic interface system.

  12. Eva Physiology, Systems, and Performance (EPSP) Project Overview

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael L.

    2007-01-01

    Extravehicular activity (EVA) is any activity performed by astronauts outside their space vehicle or habitat. EVA may be performed on orbit, such as outside the Space Shuttle or the International Space Station, or on a planetary surface such as Mars or on the moon. Astronauts wear a pressurized suit that provides environmental protection, mobility, life support, and communications while they work in the harsh conditions of a microgravity environment. Exploration missions to the moon and Mars may last many days and will include many types of EVAs; exploration, science, construction and maintenance. The effectiveness and success of these EVA-filled missions is dependent on the ability to perform tasks efficiently. The EVA Physiology, Systems and Performance (EPSP) project will conduct a number of studies to understand human performance during EVA, from a molecular level to full-scale equipment and suit design aspects, with the aim of developing safe and efficient systems for Exploration missions and the Constellation Program. The EPSP project will 1) develop Exploration Mission EVA suit requirements for metabolic and thermal loading, optional center of gravity location, biomedical sensors, hydration, nutrition, and human biomedical interactions; 2) develop validated EVA prebreathe protocols that meet medical, vehicle, and habitat constraints while minimizing crew time and thus increasing EVA work efficiency; and 3) define exploration decompression sickness (DCS) risks, policy, and mission success statistics and develop a DCS risk definition report.

  13. Phillips during EVA

    NASA Image and Video Library

    2005-08-18

    ISS011-E-11948 (18 August 2005) --- Attired in a Russian Orlan spacesuit, astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, participates in a session of extravehicular activity (EVA). The 4 hour 58 minute spacewalk by Phillips and cosmonaut Sergei K. Krikalev (seen in Phillip’;s helmet visor), commander representing Russia's Federal Space Agency, was the 62nd EVA in support of Station assembly and maintenance, the 34th conducted from the Station itself, and the 16th from the Pirs Docking Compartment.

  14. Phillips during EVA

    NASA Image and Video Library

    2005-08-18

    ISS011-E-11949 (18 August 2005) --- Attired in a Russian Orlan spacesuit, astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, participates in a session of extravehicular activity (EVA). The 4 hour 58 minute spacewalk by Phillips and cosmonaut Sergei K. Krikalev (seen in Phillip’;s helmet visor), commander representing Russia's Federal Space Agency, was the 62nd EVA in support of Station assembly and maintenance, the 34th conducted from the Station itself, and the 16th from the Pirs Docking Compartment.

  15. Phillips during EVA

    NASA Image and Video Library

    2005-08-18

    ISS011-E-11947 (18 August 2005) --- Attired in a Russian Orlan spacesuit, astronaut John L. Phillips, Expedition 11 NASA Space Station science officer and flight engineer, participates in a session of extravehicular activity (EVA). The 4 hour 58 minute spacewalk by Phillips and cosmonaut Sergei K. Krikalev (seen in Phillip’;s helmet visor), commander representing Russia's Federal Space Agency, was the 62nd EVA in support of Station assembly and maintenance, the 34th conducted from the Station itself, and the 16th from the Pirs Docking Compartment.

  16. Russian EVA 36

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028787 (9 Nov. 2013) --- Russian cosmonauts Oleg Kotov (left) and Sergey Ryazanskiy, both Expedition 37 flight engineers, attired in Russian Orlan spacesuits, participate in a session of extravehicular activity (EVA) in support of assembly and maintenance on the International Space Station. During the five-hour, 50-minute spacewalk, Kotov and Ryazanskiy continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22. Earth’s horizon and the blackness of space provide the backdrop for the scene.

  17. Thermal stability of poly(ethylene-co-vinyl acetate) based materials

    DOE PAGES

    Patel, Mogon; Pitts, Simon; Beavis, Peter; ...

    2013-03-26

    The thermal stability properties of poly (ethylene-co-vinyl acetate) composites have been studied in support of our core programmes in materials qualification and life assessment. The material is used as a binder phase for boron particles in highly filled (70 wt %) composites. Our studies show that the uncured resin readily accumulates acetic acid through hydrolysis of the pendent acetate groups which alters the acidity (pH) of the material. Thermal desorption studies in combination with gas-chromatography-mass spectrometry show that the resin readily evolves acetic acid when thermally aged to temperatures up to 75°C. Gel Permeation Chromatography (GPC) suggests that thermal ageingmore » induces a gradual reduction in resin molecular weight and confirms the susceptibility of the material to chain scission. Heating at elevated temperatures in excess of 300oC is required to induce significant changes in the carbon skeleton through deacetylation and dehydration processes and the production of unsaturated main chain double bonds. Overall, the mechanical response of these filled composites are found to be relatively complex with the extent of polymer-filler interactions possibly playing an important role in determining key engineering properties. Mechanical property studies confirm a small but significant decrease in modulus presumably linked to thermally induced chain scission of the EVA binder.« less

  18. Fast quantifying collision strength index of ethylene-vinyl acetate copolymer coverings on the fields based on near infrared hyperspectral imaging techniques

    PubMed Central

    Chen, Y. M.; Lin, P.; He, Y.; He, J. Q.; Zhang, J.; Li, X. L.

    2016-01-01

    A novel strategy based on the near infrared hyperspectral imaging techniques and chemometrics were explored for fast quantifying the collision strength index of ethylene-vinyl acetate copolymer (EVAC) coverings on the fields. The reflectance spectral data of EVAC coverings was obtained by using the near infrared hyperspectral meter. The collision analysis equipment was employed to measure the collision intensity of EVAC materials. The preprocessing algorithms were firstly performed before the calibration. The algorithms of random frog and successive projection (SP) were applied to extracting the fingerprint wavebands. A correlation model between the significant spectral curves which reflected the cross-linking attributions of the inner organic molecules and the degree of collision strength was set up by taking advantage of the support vector machine regression (SVMR) approach. The SP-SVMR model attained the residual predictive deviation of 3.074, the square of percentage of correlation coefficient of 93.48% and 93.05% and the root mean square error of 1.963 and 2.091 for the calibration and validation sets, respectively, which exhibited the best forecast performance. The results indicated that the approaches of integrating the near infrared hyperspectral imaging techniques with the chemometrics could be utilized to rapidly determine the degree of collision strength of EVAC. PMID:26875544

  19. Miniature EVA Software Defined Radio

    NASA Technical Reports Server (NTRS)

    Pozhidaev, Aleksey

    2012-01-01

    As NASA embarks upon developing the Next-Generation Extra Vehicular Activity (EVA) Radio for deep space exploration, the demands on EVA battery life will substantially increase. The number of modes and frequency bands required will continue to grow in order to enable efficient and complex multi-mode operations including communications, navigation, and tracking applications. Whether conducting astronaut excursions, communicating to soldiers, or first responders responding to emergency hazards, NASA has developed an innovative, affordable, miniaturized, power-efficient software defined radio that offers unprecedented power-efficient flexibility. This lightweight, programmable, S-band, multi-service, frequency- agile EVA software defined radio (SDR) supports data, telemetry, voice, and both standard and high-definition video. Features include a modular design, an easily scalable architecture, and the EVA SDR allows for both stationary and mobile battery powered handheld operations. Currently, the radio is equipped with an S-band RF section. However, its scalable architecture can accommodate multiple RF sections simultaneously to cover multiple frequency bands. The EVA SDR also supports multiple network protocols. It currently implements a Hybrid Mesh Network based on the 802.11s open standard protocol. The radio targets RF channel data rates up to 20 Mbps and can be equipped with a real-time operating system (RTOS) that can be switched off for power-aware applications. The EVA SDR's modular design permits implementation of the same hardware at all Network Nodes concept. This approach assures the portability of the same software into any radio in the system. It also brings several benefits to the entire system including reducing system maintenance, system complexity, and development cost.

  20. EVA console personnel during STS-61 simulations

    NASA Image and Video Library

    1993-09-01

    Susan P. Rainwater monitors an extravehicular activity (EVA) simulation from the EVA console at JSC's Mission Control Center (MCC) during joint integrated simulations for the STS-61 mission. Astronauts assigned to extravehicular activity (EVA) tasks with the Hubble Space Telescope (HST) were simultaneously rehearsing in a neutral buoyancy tank at the Marshall Space Flight Center (MSFC) in Alabama.

  1. Applications of EVA guidelines and design criteria. Volume 3: EVA systems cost model formating

    NASA Technical Reports Server (NTRS)

    Brown, N. E.

    1973-01-01

    The development of a model for estimating the impact of manned EVA costs on future payloads is discussed. Basic information on the EV crewman requirements, equipment, physical and operational characteristics, and vehicle interfaces is provided. The cost model is being designed to allow system designers to quantify the impact of EVA on vehicle and payload systems.

  2. EVA - Don't Leave Earth Without It

    NASA Technical Reports Server (NTRS)

    Cupples, J. Scott; Smith, Stephen A.

    2011-01-01

    Modern manned space programs come in two categories: those that need Extravehicular Activity (EVA) and those that will need EVA. This paper discusses major milestones in the Shuttle Program where EVA was used to save payloads, enhance on-orbit capabilities, and build structures in order to ensure success of National Aeronautics and Space Administration (NASA) missions. In conjunction, the Extravehicular Mobility Unit s (EMU) design, and hence, its capabilities evolved as its mission evolved. It is the intent that lessons can be drawn from these case studies so that EVA compatibility is designed into future vehicles and payloads.

  3. EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6893 (3 August 2005) --- Astronaut Soichi Noguchi, STS-114 mission specialist representing Japan Aerospace Exploration Agency (JAXA), participates in the mission’;s third session of extravehicular activity (EVA).

  4. EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6897 (3 August 2005) --- Astronaut Soichi Noguchi, STS-114 mission specialist representing Japan Aerospace Exploration Agency (JAXA), participates in the mission’;s third session of extravehicular activity (EVA).

  5. Use MACES IVA Suit for EVA Mobility Evaluations

    NASA Technical Reports Server (NTRS)

    Watson, Richard D.

    2014-01-01

    The use of an Intra-Vehicular Activity (IVA) suit for a spacewalk or Extra-Vehicular Activity (EVA) was evaluated for mobility and usability in the Neutral Buoyancy Lab (NBL) environment. The Space Shuttle Advanced Crew Escape Suit (ACES) has been modified (MACES) to integrate with the Orion spacecraft. The first several missions of the Orion MPCV spacecraft will not have mass available to carry an EVA specific suit so any EVA required will have to be performed by the MACES. Since the MACES was not designed with EVA in mind, it was unknown what mobility the suit would be able to provide for an EVA or if a person could perform useful tasks for an extended time inside the pressurized suit. The suit was evaluated in multiple NBL runs by a variety of subjects including crewmembers with significant EVA experience. Various functional mobility tasks performed included: translation, body positioning, carrying tools, body stabilization, equipment handling, and use of tools. Hardware configurations included with and without TMG, suit with IVA gloves and suit with EVA gloves. Most tasks were completed on ISS mockups with existing EVA tools. Some limited tasks were completed with prototype tools on a simulated rocky surface. Major findings include: demonstration of the ability to weigh-out the suit, understanding the need to have subjects perform multiple runs prior to getting feedback, determination of critical sizing factors, and need for adjustment of suit work envelop. The early testing has demonstrated the feasibility of EVA's limited duration and limited scope. Further testing is required with more flight like tasking and constraints to validate these early results. If the suit is used for EVA, it will require mission specific modifications for umbilical management or PLSS integration, safety tether attachment, and tool interfaces. These evaluations are continuing through calendar year 2014.

  6. EVA Health and Human Performance Benchmarking Study

    NASA Technical Reports Server (NTRS)

    Abercromby, A. F.; Norcross, J.; Jarvis, S. L.

    2016-01-01

    Multiple HRP Risks and Gaps require detailed characterization of human health and performance during exploration extravehicular activity (EVA) tasks; however, a rigorous and comprehensive methodology for characterizing and comparing the health and human performance implications of current and future EVA spacesuit designs does not exist. This study will identify and implement functional tasks and metrics, both objective and subjective, that are relevant to health and human performance, such as metabolic expenditure, suit fit, discomfort, suited postural stability, cognitive performance, and potentially biochemical responses for humans working inside different EVA suits doing functional tasks under the appropriate simulated reduced gravity environments. This study will provide health and human performance benchmark data for humans working in current EVA suits (EMU, Mark III, and Z2) as well as shirtsleeves using a standard set of tasks and metrics with quantified reliability. Results and methodologies developed during this test will provide benchmark data against which future EVA suits, and different suit configurations (eg, varied pressure, mass, CG) may be reliably compared in subsequent tests. Results will also inform fitness for duty standards as well as design requirements and operations concepts for future EVA suits and other exploration systems.

  7. Development, Validation and Application of a Stability Indicating HPLC Method to Quantify Lidocaine from Polyethylene-co-Vinyl Acetate (EVA) Matrices and Biological Fluids.

    PubMed

    Bhusal, Prabhat; Sharma, Manisha; Harrison, Jeff; Procter, Georgina; Andrews, Gavin; Jones, David S; Hill, Andrew G; Svirskis, Darren

    2017-09-01

    An efficient and cost-effective quantification procedure for lidocaine by HPLC has been developed to estimate lidocaine from an EVA matrix, plasma, peritoneal fluid and intra-articular fluid (IAF). This method guarantees the resolution of lidocaine from the degradation products obtained from alkaline and oxidative stress. Chromatographic separation of lidocaine was achieved with a retention time of 7 min using a C18 column with a mobile phase comprising acetonitrile and potassium dihydrogen phosphate buffer (pH 5.5; 0.02 M) in the ratio of 26:74 at a flow rate of 1 mL min-1 with detection at 230 nm. Instability of lidocaine was observed to an oxidizing (0.02% H2O2) and alkaline environments (0.1 M NaOH). The calibration curve was found to be linear within the concentration range of 0.40-50.0 μg/mL. Intra-day and inter-day accuracy ranged between 95.9% and 99.1%, with precision (% RSD) below 6.70%. The limit of quantification and limit of detection were 0.40 μg/mL and 0.025 μg/mL, respectively. The simple extraction method described enabled the quantification of lidocaine from an EVA matrix using dichloromethane as a solvent. The assay and content uniformity of lidocaine within an EVA matrix were 103 ± 3.60% and 100 ± 2.60%, respectively. The ability of this method to quantify lidocaine release from EVA films was also demonstrated. Extraction of lidocaine from plasma, peritoneal fluid and IAF followed by HPLC analysis confirmed the utility of this method for ex vivo and in vivo studies where the calibration plot was found to be linear from 1.60 to 50.0 μg/mL. © Crown copyright 2017.

  8. Helms during EVA on the ISS

    NASA Image and Video Library

    2001-04-06

    STS102-325-023 (11 March 2001) --- Astronaut Susan J. Helms completes a scheduled space walk task on the International Space Station (ISS). This extravehicular activity (EVA), on which Helms was joined by astronaut James S. Voss (out of frame), was the first of two scheduled STS-102 EVA sessions. The pair, destined to become members of the Expedition Two crew aboard the station later in the mission, rode aboard Discovery into orbit and at the time of this EVA were still regarded as STS-102 mission specialists.

  9. EVA Suit Microbial Leakage Investigation Project

    NASA Technical Reports Server (NTRS)

    Falker, Jay; Baker, Christopher; Clayton, Ronald; Rucker, Michelle

    2016-01-01

    The objective of this project is to collect microbial samples from various EVA suits to determine how much microbial contamination is typically released during simulated planetary exploration activities. Data will be released to the planetary protection and science communities, and advanced EVA system designers. In the best case scenario, we will discover that very little microbial contamination leaks from our current or prototype suit designs, in the worst case scenario, we will identify leak paths, learn more about what affects leakage--and we'll have a new, flight-certified swab tool for our EVA toolbox.

  10. Development of new EVA formulations for improved performance at NREL

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F.J.

    1997-02-01

    We review in chronological order the research stages and fundamental concepts involved in developing modified and new EVA formulations for improved performance against photo-induced degradation and discoloration. The new NREL EVA formulations use additives totally different from the present commercial formulations (EVA A9918 and EVA 15295). Validation of their long-term photostability and thermostability is presently under way. Together with UV-absorbing glass superstrates, they may offer better success in achieving a more reliable module performance and longer service life without significant EVA discoloration problems, which are commonly experienced with EVA A9918 and, at a lesser rate, EVA 15295. {copyright} {ital 1997more » American Institute of Physics.}« less

  11. EVA

    NASA Image and Video Library

    2012-08-23

    ISS032-E-024171 (30 Aug. 2012) --- Backdropped over Andros Island and other parts of the Bahamas, NASA astronaut Sunita Williams and Japan Aerospace Exploration Agency astronaut Aki Hoshide (out of frame), both Expedition 32 flight engineers, participate in a session of extravehicular activity (EVA) to continue outfitting the International Space Station.

  12. Synthesis of amphipathic block copolymers based on polyisobutylene and polyoxyethylene and their application in emulsion polymerization

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sar, B.

    1992-12-31

    Polymer colloids stabilized by polymeric surfactants are of great interest both commercially and academically. It has been found that these materials enhance latex stabilization in a number of applications. The polymeric surfactants are amphipathic block and graft copolymers containing both hydrophilic and hydrophobic moieties. The current study involved the synthesis of a series of amphipathic triblock copolymers, polyisobutylene-block-polyoxyethylene-block-polyisobutylene (PIB-b-POE-b-PIB), for use in the emulsion polymerization of styrene (STY), methyl methacrylate (MMA), and vinyl acetate (VAc). The stabilizing effectiveness of these triblock copolymers was studied as a function of their blocklength. When the molecular weight of the POE center block wasmore » changed from M{sub n} = 2,000 to 20,000 g/mole, stable lattices were obtained in emulsion polymerization with MMA, STY, and VAc as the monomers. In all cases, the polymerization rates remained constant, while the number of particles/volume decreased with increasing POE chain length. When the molecular weight of the PIB end blocks was changed from M{sub n} = 400 to 2,600 g/mole keeping the molecular weight of the POE center block constant at M{sub n} = 20,000 g/mole, the poly(methyl methacrylate) and poly(vinyl acetate) lattices exhibited similar behavior, i.e., the number of particles and particle sizes remained the same, but the rate of polymerization reached a maximum at 87 wt% POE content. In the case of poly(styrene) both the rate of polymerization and the number of particles remained constant. The emulsion polymerization of other monomers such as butadiene, acrylonitrile, methyl acrylate, ethyl acrylate, and butyl acrylate was carried out by using one triblock copolymer, i.e., PIB(400)-b-POE (8,000)-b-PIB-(400). Stable lattices were also formed in all cases.« less

  13. Climbing the Extravehicular Activity (EVA) Wall - Safely

    NASA Technical Reports Server (NTRS)

    Fuentes, Jose; Greene, Stacie

    2010-01-01

    The success of the EVA team, that includes the EVA project office, Crew Office, Mission Operations, Engineering and Safety, is assured by the full integration of all necessary disciplines. Safety participation in all activities from hardware development concepts, certification and crew training, provides for a strong partnership within the team. Early involvement of Safety on the EVA team has mitigated risk and produced a high degree of mission success.

  14. Advanced EVA system design requirements study, executive summary

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Design requirements and criteria for the space station advanced Extravehicular Activity System (EVAS) including crew enclosures, portable life support systems, maneuvering propulsion systems, and related EVA support equipment were established. The EVA mission requirements, environments, and medical and physiological requirements, as well as operational, procedures and training issues were considered.

  15. A human factors analysis of EVA time requirements

    NASA Technical Reports Server (NTRS)

    Pate, D. W.

    1996-01-01

    Human Factors Engineering (HFE), also known as Ergonomics, is a discipline whose goal is to engineer a safer, more efficient interface between humans and machines. HFE makes use of a wide range of tools and techniques to fulfill this goal. One of these tools is known as motion and time study, a technique used to develop time standards for given tasks. A human factors motion and time study was initiated with the goal of developing a database of EVA task times and a method of utilizing the database to predict how long an ExtraVehicular Activity (EVA) should take. Initial development relied on the EVA activities performed during the STS-61 mission (Hubble repair). The first step of the analysis was to become familiar with EVAs and with the previous studies and documents produced on EVAs. After reviewing these documents, an initial set of task primitives and task time modifiers was developed. Videotaped footage of STS-61 EVAs were analyzed using these primitives and task time modifiers. Data for two entire EVA missions and portions of several others, each with two EVA astronauts, was collected for analysis. Feedback from the analysis of the data will be used to further refine the primitives and task time modifiers used. Analysis of variance techniques for categorical data will be used to determine which factors may, individually or by interactions, effect the primitive times and how much of an effect they have.

  16. EVA 25

    NASA Image and Video Library

    2013-12-24

    View of Rick Mastracchio,in his Extravehicular Mobility Unit (EMU),working to mate spare Pump Module (PM) Quick Disconnects (QDs) during International Space Station (ISS) Extravehicular Activity (EVA) 25. Image was released by astronaut on Twitter.

  17. Study of space shuttle EVA/IVA support requirements. Volume 2: EVA/IVA tasks, guidelines, and constraints definition

    NASA Technical Reports Server (NTRS)

    Webbon, B. W.; Copeland, R. J.; Wood, P. W., Jr.; Cox, R. L.

    1973-01-01

    The guidelines for EVA and IVA tasks to be performed on the space shuttle are defined. In deriving tasks, guidelines, and constraints, payloads were first identified from the mission model. Payload requirements, together with man and manipulator capabilities, vehicle characteristics and operation, and safety considerations led to a definition of candidate tasks. Guidelines and constraints were also established from these considerations. Scenarios were established, and screening criteria, such as commonality of EVA and IVA activities, were applied to derive representative planned and unplanned tasks. The whole spectrum of credible contingency situations with a potential requirement for EVA/IVA was analyzed.

  18. Russian EVA 36.

    NASA Image and Video Library

    2013-11-09

    ISS037-E-028076 (9 Nov. 2013) --- Russian cosmonaut Sergey Ryazanskiy, Expedition 37 flight engineer, attired in a Russian Orlan spacesuit, uses a digital still camera to expose a photo of his helmet visor during a session of extravehicular activity (EVA) as work continues on the International Space Station. Also visible in the reflections in the visor are Russian cosmonaut Oleg Kotov, flight engineer, and various components of the space station and a blue and white portion of Earth. During the five-hour, 50-minute spacewalk, Kotov and Ryazanskiy continued the setup of a combination EVA workstation and biaxial pointing platform that was installed during an Expedition 36 spacewalk on Aug. 22.

  19. Extravehicular Activity (EVA) Microbial Swab Tool

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle

    2015-01-01

    When we send humans to search for life on Mars, we'll need to know what we brought with us versus what may already be there. To ensure our crewed spacecraft meet planetary protection requirements--and to protect our science from human contamination--we'll need to know whether micro-organisms are leaking/venting from our ships and spacesuits. This is easily done by swabbing external vents and surfaces for analysis, but there was no US EVA tool for that job. NASA engineers developed an EVA-compatible swab tool that can be used to collect data on current hardware, which will influence eventual Mars life support and EVA hardware designs.

  20. Creating a Lunar EVA Work Envelope

    NASA Technical Reports Server (NTRS)

    Griffin, Brand N.; Howard, Robert; Rajulu, Sudhakar; Smitherman, David

    2009-01-01

    A work envelope has been defined for weightless Extravehicular Activity (EVA) based on the Space Shuttle Extravehicular Mobility Unit (EMU), but there is no equivalent for planetary operations. The weightless work envelope is essential for planning all EVA tasks because it determines the location of removable parts, making sure they are within reach and visibility of the suited crew member. In addition, using the envelope positions the structural hard points for foot restraints that allow placing both hands on the job and provides a load path for reacting forces. EVA operations are always constrained by time. Tasks are carefully planned to ensure the crew has enough breathing oxygen, cooling water, and battery power. Planning first involves computers using a virtual work envelope to model tasks, next suited crew members in a simulated environment refine the tasks. For weightless operations, this process is well developed, but planetary EVA is different and no work envelope has been defined. The primary difference between weightless and planetary work envelopes is gravity. It influences anthropometry, horizontal and vertical mobility, and reaction load paths and introduces effort into doing "overhead" work. Additionally, the use of spacesuits other than the EMU, and their impacts on range of motion, must be taken into account. This paper presents the analysis leading to a concept for a planetary EVA work envelope with emphasis on lunar operations. There is some urgency in creating this concept because NASA has begun building and testing development hardware for the lunar surface, including rovers, habitats and cargo off-loading equipment. Just as with microgravity operations, a lunar EVA work envelope is needed to guide designers in the formative stages of the program with the objective of avoiding difficult and costly rework.

  1. EVA1A inhibits GBM cell proliferation by inducing autophagy and apoptosis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Shen, Xue; Kan, Shifeng; Liu, Zhen

    Eva-1 homolog A (EVA1A) is a novel lysosome and endoplasmic reticulum-associated protein involved in autophagy and apoptosis. In this study, we constructed a recombinant adenovirus 5-EVA1A vector (Ad5-EVA1A) to overexpress EVA1A in glioblastoma (GBM) cell lines and evaluated its anti-tumor activities in vitro and in vivo. We found that overexpression of EVA1A in three GBM cell lines (U251, U87 and SHG44) resulted in a suppression of tumor cell growth via activation of autophagy and induction of cell apoptosis in a dose- and time-dependent manner. EVA1A-mediated autophagy was associated with inactivation of the mTOR/RPS6KB1 signaling pathway. Furthermore in vivo, overexpression ofmore » EVA1A successfully inhibited tumor growth in NOD/SCID mice. Our data suggest that EVA1A-induced autophagy and apoptosis play a role in suppressing the development of GBM and their up-regulation may be an effective method for treating this form of cancer. - Highlights: • Overexpression of EVA1A suppresses GBM cell growth. • EVA1A induces autophagy through the mTOR/RPS6KB1 pathway. • EVA1A induces GBM cell apoptosis. • EVA1A inhibits the development of GBM in vivo.« less

  2. Artemyev post-EVA

    NASA Image and Video Library

    2014-06-19

    Cosmonaut Oleg Artemyev, Expedition 40 flight engineer, is photographed still wearing his liquid cooling and ventilation garment after a Russian Extravehicular Activity (EVA). Artemyev is standing in his crew quarters (CQ).

  3. EVA-Compatible Microbial Swab Tool

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle A.

    2016-01-01

    When we send humans to search for life on Mars, we'll need to know what we brought with us versus what may already be there. To ensure our crewed spacecraft meet planetary protection requirements—and to protect our science from human contamination—we'll need to know whether micro-organisms are leaking/venting from our ships and spacesuits. This is easily done by swabbing external vents and suit surfaces for analysis, but requires a specialized tool for the job. Engineers at the National Aeronautics and Space Administration (NASA) recently developed an Extravehicular Activity (EVA)-compatible swab tool that can be used to sample current space suits and life support systems. Data collected now will influence Mars life support and EVA hardware early in the planning process, before design changes become difficult and expensive.NASA’s EVA swab tool pairs a Space Shuttle-era tool handle with a commercially available swab tip mounted into a custom-designed end effector. A glove-compatible release mechanism allows the handle to quickly switch between swab tips, much like a shaving razor handle can snap onto a disposable blade cartridge. Swab tips are stowed inside individual sterile containers, each fitted with a microbial filter that allows the container to equalize atmospheric pressure, but prevents cabin contaminants from rushing into the container when passing from the EVA environment into a pressurized cabin. A bank of containers arrayed inside a tool caddy allows up to six individual samples to be collected during a given spacewalk.NASA plans to use the tool in 2016 to collect samples from various spacesuits during ground testing to determine what (if any) human-borne microbial contamination leaks from the suit under simulated thermal vacuum conditions. Next, the tool will be used on board the International Space Station to assess the types of microbial contaminants found on external environmental control and life support system vents. Data will support

  4. Mars EVA Suit Airlock (MESA)

    NASA Astrophysics Data System (ADS)

    Ransom, Stephen; Böttcher, Jörg; Steinsiek, Frank

    The Astrium Space Infrastructure Division has begun an in-house research activity of an Earth-based simulation facility supporting future manned missions to Mars. This research unit will help to prepare and support planned missions in the following ways: 1) to enable the investigation and analysis of contamination issues in advance of a human visit to Mars; 2) as a design tool to investigate and simulate crew operations; 3) to simulate crew operation during an actual mission; 4) to enable on-surface scientific operations without leaving the shirt-sleeve habitation environment ("glove box principle"). The MESA module is a surface EVA facility attached to the main habitation or laboratory module, or mobile pressurized rover. It will be sealed, but not pressurized, and provide protection against the harsh Martian environment. This module will include a second crew airlock for safety reasons. The compartment can also be used to provide an external working bench and experiment area for the crew. A simpler MESA concept provides only an open shelter against wind and dust. This concept does not incorporate working and experimental areas. The principle idea behind the MESA concept is to tackle the issue of contamination by minimizing the decontamination processes needed to clean surface equipment and crew suit surfaces after an EVA excursion prior to the astronaut re-entering the habitable area. The technical solution envisages the use of a dedicated crew suit airlock. This airlock uses an EVA suit which is externally attached by its back-pack to the EVA compartment area facing the Martian environment. The crew donns the suit from inside the habitable volume through the airlock on the back of the suit. The surface EVA can be accomplished after closing the back-pack and detaching the suit. A special technical design concept foresees an extendable suit back-pack, so that the astronaut can operate outside and in the vincinity of the module. The key driver in the investigation

  5. Study on thermal properties and crystallization behavior of electron beam irradiated ethylene vinyl acetate (EVA)/waste tyre dust (WTD) blends in the presence of polyethylene graft maleic anhydride (PEgMAH)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ramli, Syuhada; Ahmad, S. H.; Ratnam, C. T.

    2013-11-27

    The aim of this article is to show the effects of the electron beam irradiation dose and presence of a compatibiliser on the thermal properties and crystallinity of EVA/WTD blends. The purpose of applying electron beam radiation with doses range 50 to 200 kGy and adding a compatibiliser was to enhance the compatibility of the studied blends and at the same time to investigate the possibility of using this technique in the process of recycling polymeric materials. As the compatibilisers, the polyethylene grafted maleic anhydride (PEgMAH) was utilized, they were added at the amounts of 1-5 phr respectively. The enhancementmore » of thermal properties was accompanied by the following effects, discussed in this article: i) an irradiated EVA/WTD blend at 200kGy was found to improve the thermal properties of EVA, ii) the addition of PEgMAH in EVA/WTD blends and the subsequent irradiation allowed prevention of degradation mechanism. iii) the ΔH{sub f} and crystallinity percentage decrease at higher PEgMAH content.« less

  6. EVA Retriever Demonstration

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The EVA retriever is demonstrated in the Manipulator Development Facility (MDF). The retriever moves on the air bearing table 'searching' for its target, in this case tools 'dropped' by astronauts on orbit.

  7. Potential roles for EVA and telerobotics in a unified worksite

    NASA Astrophysics Data System (ADS)

    Akin, David; Howard, Russel D.

    1993-02-01

    Although telerobotics and extravehicular activity (EVA) are often portrayed as competitive approaches to space operations, ongoing research in the Space Systems Laboratory (SSL) has demonstrated the utility of cooperative roles in an integrated EVA/telerobotic work site. Working in the neutral buoyancy simulation environment, tests were performed on interactive roles or EVA subjects and telerobots in structural assembly and satellite servicing tasks. In the most elaborate of these tests to date, EVA subjects were assisted by the SSL's Beam Assembly Teleoperator (BAT) in several servicing tasks planned for Hubble Space Telescope, using the high-fidelity crew training article in the NASA Marshall Neutral Buoyancy Simulator. These tests revealed several shortcomings in the design of BAT for satellite servicing and demonstrated the utility of a free-flying or RMS-mounted telerobot for providing EVA crew assistance. This paper documents the past tests, including the use of free-flying telerobots to effect the rescue of a simulated incapacitated EVA subject, and details planned future efforts in this area, including the testing of a new telerobotic system optimized for the satellite servicing role, the development of dedicated telerobotic devices designed specifically for assisting EVA crew, and conceptual approaches to advanced EVA/telerobotic operations such as the Astronaut Operations Vehicle.

  8. EVA/ORU model architecture using RAMCOST

    NASA Technical Reports Server (NTRS)

    Ntuen, Celestine A.; Park, Eui H.; Wang, Y. M.; Bretoi, R.

    1990-01-01

    A parametrically driven simulation model is presented in order to provide a detailed insight into the effects of various input parameters in the life testing of a modular space suit. The RAMCOST model employed is a user-oriented simulation model for studying the life-cycle costs of designs under conditions of uncertainty. The results obtained from the EVA simulated model are used to assess various mission life testing parameters such as the number of joint motions per EVA cycle time, part availability, and number of inspection requirements. RAMCOST first simulates EVA completion for NASA application using a probabilistic like PERT network. With the mission time heuristically determined, RAMCOST then models different orbital replacement unit policies with special application to the astronaut's space suit functional designs.

  9. One-step route to the fabrication of highly porous polyaniline nanofiber films by using PS-b-PVP diblock copolymers as templates.

    PubMed

    Li, Xue; Tian, Shengjun; Ping, Yang; Kim, Dong Ha; Knoll, Wolfgang

    2005-10-11

    We report a new method to control both the nucleation and growth of highly porous polyaniline (PANI) nanofiber films using porous poly(styrene-block-2-vinylpyridine) diblock copolymer (PS-b-P2VP) films as templates. A micellar thin film composed of P2VP spheres within a PS matrix is prepared by spin coating a PS-b-P2VP micellar solution onto substrates. The P2VP domains are swollen in a selective solvent of acetic acid, which results in the formation of pores in the block copolymer film. PANI is then deposited onto the substrates modified with such a porous film using electrochemical methods. During the deposition, the nucleation and growth of PANI occur only at the pores of the block copolymer film. After the continued growth of PANI by the electrochemical deposition, a porous PANI nanofiber film is obtained.

  10. A Human Machine Interface for EVA

    NASA Astrophysics Data System (ADS)

    Hartmann, L.

    EVA astronauts work in a challenging environment that includes high rate of muscle fatigue, haptic and proprioception impairment, lack of dexterity and interaction with robotic equipment. Currently they are heavily dependent on support from on-board crew and ground station staff for information and robotics operation. They are limited to the operation of simple controls on the suit exterior and external robot controls that are difficult to operate because of the heavy gloves that are part of the EVA suit. A wearable human machine interface (HMI) inside the suit provides a powerful alternative for robot teleoperation, procedure checklist access, generic equipment operation via virtual control panels and general information retrieval and presentation. The HMI proposed here includes speech input and output, a simple 6 degree of freedom (dof) pointing device and a heads up display (HUD). The essential characteristic of this interface is that it offers an alternative to the standard keyboard and mouse interface of a desktop computer. The astronaut's speech is used as input to command mode changes, execute arbitrary computer commands and generate text. The HMI can respond with speech also in order to confirm selections, provide status and feedback and present text output. A candidate 6 dof pointing device is Measurand's Shapetape, a flexible "tape" substrate to which is attached an optic fiber with embedded sensors. Measurement of the modulation of the light passing through the fiber can be used to compute the shape of the tape and, in particular, the position and orientation of the end of the Shapetape. It can be used to provide any kind of 3d geometric information including robot teleoperation control. The HUD can overlay graphical information onto the astronaut's visual field including robot joint torques, end effector configuration, procedure checklists and virtual control panels. With suitable tracking information about the position and orientation of the EVA suit

  11. EVA Glove Research Team

    NASA Technical Reports Server (NTRS)

    Strauss, Alvin M.; Peterson, Steven W.; Main, John A.; Dickenson, Rueben D.; Shields, Bobby L.; Lorenz, Christine H.

    1992-01-01

    The goal of the basic research portion of the extravehicular activity (EVA) glove research program is to gain a greater understanding of the kinematics of the hand, the characteristics of the pressurized EVA glove, and the interaction of the two. Examination of the literature showed that there existed no acceptable, non-invasive method of obtaining accurate biomechanical data on the hand. For this reason a project was initiated to develop magnetic resonance imaging as a tool for biomechanical data acquisition and visualization. Literature reviews also revealed a lack of practical modeling methods for fabric structures, so a basic science research program was also initiated in this area.

  12. A Human Factors Analysis of EVA Time Requirements

    NASA Technical Reports Server (NTRS)

    Pate, Dennis W.

    1997-01-01

    Human Factors Engineering (HFE) is a discipline whose goal is to engineer a safer, more efficient interface between humans and machines. HFE makes use of a wide range of tools and techniques to fulfill this goal. One of these tools is known as motion and time study, a technique used to develop time standards for given tasks. During the summer of 1995, a human factors motion and time study was initiated with the goals of developing a database of EVA task times and developing a method of utilizing the database to predict how long an EVA should take. Initial development relied on the EVA activities performed during the STS-61 (Hubble) mission. The first step of the study was to become familiar with EVA's, the previous task-time studies, and documents produced on EVA's. After reviewing these documents, an initial set of task primitives and task-time modifiers was developed. Data was collected from videotaped footage of two entire STS-61 EVA missions and portions of several others, each with two EVA astronauts. Feedback from the analysis of the data was used to further refine the primitives and modifiers used. The project was continued during the summer of 1996, during which data on human errors was also collected and analyzed. Additional data from the STS-71 mission was also collected. Analysis of variance techniques for categorical data was used to determine which factors may affect the primitive times and how much of an effect they have. Probability distributions for the various task were also generated. Further analysis of the modifiers and interactions is planned.

  13. Astronaut Ronald Evans photographed during transearth coast EVA

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Astronaut Ronald E. Evans is photographed performing extravehicular activity (EVA) during the Apollo 17 spacecraft's transearth coast. During his EVA Command Module pilot Evans retrieved film cassettes from the Lunar Sounder, Mapping Camera, and Panoramic Camera. The total time for the transearth EVA was one hour seven minutes 19 seconds, starting at ground elapsed time of 257:25 (2:28 p.m.) amd ending at ground elapsed time of 258:42 (3:35 p.m.) on Sunday, December 17, 1972.

  14. EVA 3

    NASA Image and Video Library

    2004-08-03

    S114-E-6856 (3 August 2005) --- Backdropped by the blackness of space, astronaut Soichi Noguchi, STS-114 mission specialist representing the Japan Aerospace Exploration Agency (JAXA), traverses along the P6 truss near the arrays on the international space station during the mission’s third session of extravehicular activity (EVA).

  15. EVA1A inhibits GBM cell proliferation by inducing autophagy and apoptosis.

    PubMed

    Shen, Xue; Kan, Shifeng; Liu, Zhen; Lu, Guang; Zhang, Xiaoyan; Chen, Yingyu; Bai, Yun

    2017-03-01

    Eva-1 homolog A (EVA1A) is a novel lysosome and endoplasmic reticulum-associated protein involved in autophagy and apoptosis. In this study, we constructed a recombinant adenovirus 5-EVA1A vector (Ad5-EVA1A) to overexpress EVA1A in glioblastoma (GBM) cell lines and evaluated its anti-tumor activities in vitro and in vivo. We found that overexpression of EVA1A in three GBM cell lines (U251, U87 and SHG44) resulted in a suppression of tumor cell growth via activation of autophagy and induction of cell apoptosis in a dose- and time-dependent manner. EVA1A-mediated autophagy was associated with inactivation of the mTOR/RPS6KB1 signaling pathway. Furthermore in vivo, overexpression of EVA1A successfully inhibited tumor growth in NOD/SCID mice. Our data suggest that EVA1A-induced autophagy and apoptosis play a role in suppressing the development of GBM and their up-regulation may be an effective method for treating this form of cancer. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. EVA Design, Verification, and On-Orbit Operations Support Using Worksite Analysis

    NASA Technical Reports Server (NTRS)

    Hagale, Thomas J.; Price, Larry R.

    2000-01-01

    The International Space Station (ISS) design is a very large and complex orbiting structure with thousands of Extravehicular Activity (EVA) worksites. These worksites are used to assemble and maintain the ISS. The challenge facing EVA designers was how to design, verify, and operationally support such a large number of worksites within cost and schedule. This has been solved through the practical use of computer aided design (CAD) graphical techniques that have been developed and used with a high degree of success over the past decade. The EVA design process allows analysts to work concurrently with hardware designers so that EVA equipment can be incorporated and structures configured to allow for EVA access and manipulation. Compliance with EVA requirements is strictly enforced during the design process. These techniques and procedures, coupled with neutral buoyancy underwater testing, have proven most valuable in the development, verification, and on-orbit support of planned or contingency EVA worksites.

  17. "Astronaut STS-123 EVA 1, NBL Training"

    NASA Image and Video Library

    2007-04-18

    • Event (Mission for flight / Class for training): STS-118 (13A.1) • Title: STS-118 EVA 1 NBL • Date: 4-18-07 • Location: NBL • Key words: 118, 13A.1, S5, NBL • Description: NBL underwater photos of STS-118 EVA 1 S5 install.

  18. Mission control activity during STS-61 EVA

    NASA Image and Video Library

    1993-12-07

    Flight controller Susan P. Rainwater observes as two astronauts work through a lengthy period of extravehicular activity (EVA) in the cargo bay of the Earth-looking Space Shuttle Endeavour. Rainwater's EVA console was one of Mission Control's busiest during this eleven-day Hubble Space Telescope (HST) servicing mission in Earth orbit.

  19. An Experimental Investigation of Dextrous Robots Using EVA Tools and Interfaces

    NASA Technical Reports Server (NTRS)

    Ambrose, Robert; Culbert, Christopher; Rehnmark, Frederik

    2001-01-01

    This investigation of robot capabilities with extravehicular activity (EVA) equipment looks at how improvements in dexterity are enabling robots to perform tasks once thought to be beyond machines. The approach is qualitative, using the Robonaut system at the Johnson Space Center (JSC), performing task trials that offer a quick look at this system's high degree of dexterity and the demands of EVA. Specific EVA tools attempted include tether hooks, power torque tools, and rock scoops, as well as conventional tools like scissors, wire strippers, forceps, and wrenches. More complex EVA equipment was also studied, with more complete tasks that mix tools, EVA hand rails, tethers, tools boxes, PIP pins, and EVA electrical connectors. These task trials have been ongoing over an 18 month period, as the Robonaut system evolved to its current 43 degree of freedom (DOF) configuration, soon to expand to over 50. In each case, the number of teleoperators is reported, with rough numbers of attempts and their experience level, with a subjective difficulty rating assigned to each piece of EVA equipment and function. JSC' s Robonaut system was successful with all attempted EVA hardware, suggesting new options for human and robot teams working together in space.

  20. European EVA decompression sickness risks

    NASA Astrophysics Data System (ADS)

    Vogt, Lorenz; Wenzel, Jürgen; Skoog, A. I.; Luck, S.; Svensson, Bengt

    For the first manned flight of Hermes there will be a capability of performing EVA. The European EVA Space Suit will be an anthropomorphic system with an internal pressure of 500 hPa of pure oxygen. The pressure reduction from the Hermes cabin pressure of 1013 hPa will induce a risk for Decompression Sickness (DCS) for the EVA crewmember if no adequate protective procedures are implemented. Specific decompression procedures have to be developed. From a critical review of the literature and by using knowledge gained from research conducted in the past in the fields of diving and aerospace medicine safe protective procedures are proposed for the European EVA scenario. An R factor of 1.2 and a tissue half-time ( t1/2) of 360 minutes in a single-tissue model have been identified as appropriate operational values. On the basis of an acceptable risk level of approximately 1%, oxygen prebreathing times are proposed for (a) direct pressure reduction from 1013 hPa to a suit pressure of 500 hPa, and (b) staged decompression using a 700 hPa intermediate stage in the spacecraft cabin. In addition, factors which influence individual susceptibility to DCS are identified. Recommendations are also given in the areas of crew selection and medical monitoring requirements together with therapeutic measures that can be implemented in the Hermes scenario. A method for demonstration of the validity of proposed risks and procedures is proposed.

  1. Russian EVA 33

    NASA Image and Video Library

    2013-06-24

    View of Russian cosmonaut Alexander Misurkin (bottom center), Expedition 36 flight engineer, participating in Russian extravehicular activity (EVA) 33. Also visible are the Progress spacecraft docked to the Pirs Docking Compartment (DC1) with the Service Module (SM) .

  2. Minimizing EVA Airlock Time and Depress Gas Losses

    NASA Technical Reports Server (NTRS)

    Trevino, Luis A.; Lafuse, Sharon A.

    2008-01-01

    This paper describes the need and solution for minimizing EVA airlock time and depress gas losses using a new method that minimizes EVA out-the-door time for a suited astronaut and reclaims most of the airlock depress gas. This method consists of one or more related concepts that use an evacuated reservoir tank to store and reclaim the airlock depress gas. The evacuated tank can be an inflatable tank, a spent fuel tank from a lunar lander descent stage, or a backup airlock. During EVA airlock operations, the airlock and reservoir would be equalized at some low pressure, and through proper selection of reservoir size, most of the depress gas would be stored in the reservoir for later reclamation. The benefit of this method is directly applicable to long duration lunar and Mars missions that require multiple EVA missions (up to 100, two-person lunar EVAs) and conservation of consumables, including depress pump power and depress gas. The current ISS airlock gas reclamation method requires approximately 45 minutes of the astronaut s time in the airlock and 1 KW in electrical power. The proposed method would decrease the astronaut s time in the airlock because the depress gas is being temporarily stored in a reservoir tank for later recovery. Once the EVA crew is conducting the EVA, the volume in the reservoir would be pumped back to the cabin at a slow rate. Various trades were conducted to optimize this method, which include time to equalize the airlock with the evacuated reservoir versus reservoir size, pump power to reclaim depress gas versus time allotted, inflatable reservoir pros and cons (weight, volume, complexity), and feasibility of spent lunar nitrogen and oxygen tanks as reservoirs.

  3. EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6918 (3 August 2005) --- Astronaut Stephen K. Robinson, STS-114 mission specialist, anchored to a foot restraint on the extended International Space Station’;s Canadarm2, participates in the mission’;s third session of extravehicular activity (EVA). The blackness of space and Earth’;s horizon form the backdrop for the image.

  4. EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-06919 (3 Aug. 2005) --- Astronaut Stephen K. Robinson, STS-114 mission specialist, anchored to a foot restraint on the extended International Space Station’;s Canadarm2, participates in the mission’;s third session of extravehicular activity (EVA). The blackness of space and Earth’;s horizon form the backdrop for the image.

  5. Astronaut Ronald Evans photographed during transearth coast EVA

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Astronaut Ronald E. Evans is photographed performing extravehicular activity (EVA) during the Apollo 17 spacecraft's transearth coast. During his EVA Command Module pilot Evans retrieved film cassettes from the Lunar Sounder, Mapping Camera, and Panoramic Camera. The cylindrical object at Evans left side is the mapping camera cassette. The total time for the transearth EVA was one hour seven minutes 19 seconds, starting at ground elapsed time of 257:25 (2:28 p.m.) amd ending at ground elapsed time of 258:42 (3:35 p.m.) on Sunday, December 17, 1972.

  6. Russian EVA 39.

    NASA Image and Video Library

    2014-08-18

    ISS040E099104 (08/18/2014) --- View of Cosmonaut Oleg Artemyev (blue stripe), Expedition 40 flight engineer outside the International Space Station, taken while performing maintenance work on the Russian segment during the Russian EVA 39 on Aug 18 2014.

  7. Shkaplerov works with EVA Hardware in the SM

    NASA Image and Video Library

    2012-02-03

    ISS030-E-061158 (3 Feb. 2012) --- Russian cosmonaut Oleg Kononenko, Expedition 30 flight engineer, works with extravehicular activity (EVA) hardware in the Zvezda Service Module of the International Space Station in preparation for an EVA scheduled for Feb. 16, 2012.

  8. Shkaplerov works with EVA Hardware in the SM

    NASA Image and Video Library

    2012-02-03

    ISS030-E-061157 (3 Feb. 2012) --- Russian cosmonaut Anton Shkaplerov, Expedition 30 flight engineer, works with extravehicular activity (EVA) hardware in the Zvezda Service Module of the International Space Station in preparation for an EVA scheduled for Feb. 16, 2012.

  9. Protein based Block Copolymers

    PubMed Central

    Rabotyagova, Olena S.; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    Advances in genetic engineering have led to the synthesis of protein-based block copolymers with control of chemistry and molecular weight, resulting in unique physical and biological properties. The benefits from incorporating peptide blocks into copolymer designs arise from the fundamental properties of proteins to adopt ordered conformations and to undergo self-assembly, providing control over structure formation at various length scales when compared to conventional block copolymers. This review covers the synthesis, structure, assembly, properties, and applications of protein-based block copolymers. PMID:21235251

  10. Russian EVA 39

    NASA Image and Video Library

    2014-08-18

    ISS040E099874 (08/18/2014) --- Cosmonauts Alexander Skvortsov (red stripe - foreground) and Oleg Artemyev (blue stripe - background), Expedition 40 flight engineers, move to the Russian Service Module for repairs during International Space Station Russian EVA 39 on Aug. 18, 2014.

  11. EVA: Evryscopes for the Arctic and Antarctic

    NASA Astrophysics Data System (ADS)

    Richichi, A.; Law, N.; Tasuya, O.; Fors, O.; Dennihy, E.; Carlberg, R.; Tuthill, P.; Ashley, M.; Soonthornthum, B.

    2017-06-01

    We are planning to build Evryscopes for the Arctic and Antarctic (EVA), which will enable the first ultra-wide-field, high-cadence sky survey to be conducted from both Poles. The system is based on the successful Evryscope concept, already installed and operating since 2015 at Cerro Tololo in Chile with the following characteristics: robotic operation, 8,000 square degrees simultaneous sky coverage, 2-minute cadence, milli-mag level photometric accuracy, pipelined data processing for real-time analysis and full data storage for off-line analysis. The initial location proposed for EVA is the PEARL station on Ellesmere island; later also an antarctic location shall be selected. The science goals enabled by this unique combination of almost full-sky coverage and high temporal cadence are numerous, and include among others ground-breaking forays in the fields of exoplanets, stellar variability, asteroseismology, supernovae and other transient events. The EVA polar locations will enable uninterrupted observations lasting in principle over weeks and months. EVA will be fully robotic. We discuss the EVA science drivers and expected results, and present the logistics and the outline of the project which is expected to have first light in the winter of 2018. The cost envelope can be kept very competitive thanks to R&D already employed for the CTIO Evryscope, to our experience with both Arctic and Antarctic locations, and to the use of off-the-shelf components.

  12. EVA manipulation and assembly of space structure columns

    NASA Technical Reports Server (NTRS)

    Loughead, T. E.; Pruett, E. C.

    1980-01-01

    Assembly techniques and hardware configurations used in assembly of the basic tetrahedral cell by A7LB pressure-suited subjects in a neutral bouyancy simulator were studied. Eleven subjects participated in assembly procedures which investigated two types of structural members and two configurations of attachment hardware. The assembly was accomplished through extra-vehicular activity (EVA) only, EVA with simulated manned maneuvering unit (MMU), and EVA with simulated MMU and simulated remote manipulator system (RMS). Assembly times as low as 10.20 minutes per tetrahedron were achieved. Task element data, as well as assembly procedures, are included.

  13. Compiling a Comprehensive EVA Training Dataset for NASA Astronauts

    NASA Technical Reports Server (NTRS)

    Laughlin, M. S.; Murray, J. D.; Lee, L. R.; Wear, M. L.; Van Baalen, M.

    2016-01-01

    Training for a spacewalk or extravehicular activity (EVA) is considered a hazardous duty for NASA astronauts. This places astronauts at risk for decompression sickness as well as various musculoskeletal disorders from working in the spacesuit. As a result, the operational and research communities over the years have requested access to EVA training data to supplement their studies. The purpose of this paper is to document the comprehensive EVA training data set that was compiled from multiple sources by the Lifetime Surveillance of Astronaut Health (LSAH) epidemiologists to investigate musculoskeletal injuries. The EVA training dataset does not contain any medical data, rather it only documents when EVA training was performed, by whom and other details about the session. The first activities practicing EVA maneuvers in water were performed at the Neutral Buoyancy Simulator (NBS) at the Marshall Spaceflight Center in Huntsville, Alabama. This facility opened in 1967 and was used for EVA training until the early Space Shuttle program days. Although several photographs show astronauts performing EVA training in the NBS, records detailing who performed the training and the frequency of training are unavailable. Paper training records were stored within the NBS after it was designated as a National Historic Landmark in 1985 and closed in 1997, but significant resources would be needed to identify and secure these records, and at this time LSAH has not pursued acquisition of these early training records. Training in the NBS decreased when the Johnson Space Center in Houston, Texas, opened the Weightless Environment Training Facility (WETF) in 1980. Early training records from the WETF consist of 11 hand-written dive logbooks compiled by individual workers that were digitized at the request of LSAH. The WETF was integral in the training for Space Shuttle EVAs until its closure in 1998. The Neutral Buoyancy Laboratory (NBL) at the Sonny Carter Training Facility near JSC

  14. Space Station Human Factors Research Review. Volume 1: EVA Research and Development

    NASA Technical Reports Server (NTRS)

    Cohen, Marc M. (Editor); Vykukal, H. C. (Editor)

    1988-01-01

    An overview is presented of extravehicular activity (EVA) research and development activities at Ames. The majority of the program was devoted to presentations by the three contractors working in parallel on the EVA System Phase A Study, focusing on Implications for Man-Systems Design. Overhead visuals are included for a mission results summary, space station EVA requirements and interface accommodations summary, human productivity study cross-task coordination, and advanced EVAS Phase A study implications for man-systems design. Articles are also included on subsea approach to work systems development and advanced EVA system design requirements.

  15. Williams during EVA 36

    NASA Image and Video Library

    2016-08-19

    Extravehicular crewmember 1 (EV1) Jeff Williams pauses for a photo after installing a Hemispherical (Hemi) Reflector Cover on Pressurized Mating Adapter 2 (PMA-2) during Extravehicular Activity 36 (EVA 36).

  16. Main-chain supramolecular block copolymers.

    PubMed

    Yang, Si Kyung; Ambade, Ashootosh V; Weck, Marcus

    2011-01-01

    Block copolymers are key building blocks for a variety of applications ranging from electronic devices to drug delivery. The material properties of block copolymers can be tuned and potentially improved by introducing noncovalent interactions in place of covalent linkages between polymeric blocks resulting in the formation of supramolecular block copolymers. Such materials combine the microphase separation behavior inherent to block copolymers with the responsiveness of supramolecular materials thereby affording dynamic and reversible materials. This tutorial review covers recent advances in main-chain supramolecular block copolymers and describes the design principles, synthetic approaches, advantages, and potential applications.

  17. Astronaut David Scott practicing for Gemini 8 EVA

    NASA Image and Video Library

    1966-02-01

    S66-19284 (1 Feb. 1966) --- Astronaut David R. Scott practicing for Gemini-8 extravehicular activity (EVA) in building 4 of the Manned Spacecraft Center on the air bearing floor. He is wearing the Hand-Held Maneuvering Unit which he will use during the EVA. Photo credit: NASA

  18. Crosscutting Development- EVA Tools and Geology Sample Acquisition

    NASA Technical Reports Server (NTRS)

    2011-01-01

    Exploration to all destinations has at one time or another involved the acquisition and return of samples and context data. Gathered at the summit of the highest mountain, the floor of the deepest sea, or the ice of a polar surface, samples and their value (both scientific and symbolic) have been a mainstay of Earthly exploration. In manned spaceflight exploration, the gathering of samples and their contextual information has continued. With the extension of collecting activities to spaceflight destinations comes the need for geology tools and equipment uniquely designed for use by suited crew members in radically different environments from conventional field geology. Beginning with the first Apollo Lunar Surface Extravehicular Activity (EVA), EVA Geology Tools were successfully used to enable the exploration and scientific sample gathering objectives of the lunar crew members. These early designs were a step in the evolution of Field Geology equipment, and the evolution continues today. Contemporary efforts seek to build upon and extend the knowledge gained in not only the Apollo program but a wealth of terrestrial field geology methods and hardware that have continued to evolve since the last lunar surface EVA. This paper is presented with intentional focus on documenting the continuing evolution and growing body of knowledge for both engineering and science team members seeking to further the development of EVA Geology. Recent engineering development and field testing efforts of EVA Geology equipment for surface EVA applications are presented, including the 2010 Desert Research and Technology Studies (Desert RATs) field trial. An executive summary of findings will also be presented, detailing efforts recommended for exotic sample acquisition and pre-return curation development regardless of planetary or microgravity destination.

  19. STS-64 extravehicular activity (EVA) hardware view

    NASA Image and Video Library

    1993-01-21

    S93-26920 (8 Sept. 1994) --- Scott Bleisath, an extravehicular activity (EVA) engineer, demonstrates the hand control module for the Simplified Aid for EVA Rescue (SAFER) system making its first flight on the scheduled September STS-64 mission. Astronauts Mark C. Lee and Carl J. Meade are the spacewalkers assigned to test the system in space. Photo credit: NASA or National Aeronautics and Space Administration

  20. Asteroid Redirect Crewed Mission Space Suit and EVA System Architecture Trade Study

    NASA Technical Reports Server (NTRS)

    Blanco, Raul A.; Bowie, Jonathan T.; Watson, Richard D.; Sipila, Stephanie A.

    2014-01-01

    The Asteroid Redirect Crewed Mission (ARCM) requires a Launch/Entry/Abort (LEA) suit capability and short duration Extra Vehicular Activity (EVA) capability for Orion. The EVAs will involve a two-person crew for approximately four hours. Currently, two EVAs are planned with one contingency EVA in reserve. Providing this EVA capability is very challenging due to system level constraints and a new and unknown environment. The goal of the EVA architecture for ARCM is one that builds upon previously developed technologies and lessons learned, and that accomplishes the ARCM mission while providing a stepping stone to future missions and destinations. The primary system level constraints are to 1) minimize system mass and volume and 2) minimize the interfacing impacts to the baseline Orion design. In order to minimize the interfacing impacts and to not perturb the baseline Orion schedule, the concept of adding "kits" to the baseline system is proposed. These kits consist of: an EVA kit (converts LEA suit to EVA suit), EVA Servicing and Recharge Kit (provides suit consumables), the EVA Tools, Translation Aids & Sample Container Kit (the tools and mobility aids to complete the tasks), the EVA Communications Kit (interface between the EVA radio and the MPCV), and the Cabin Repress Kit (represses the MPCV between EVAs). This paper will focus on the trade space, analysis, and testing regarding the space suit (pressure garment and life support system). Historical approaches and lessons learned from all past EVA operations were researched. Previous and current, successfully operated EVA hardware and high technology readiness level (TRL) hardware were evaluated, and a trade study was conducted for all possible pressure garment and life support options. Testing and analysis was conducted and a recommended EVA system architecture was proposed. Pressure garment options that were considered for this mission include the currently in-use ISS EVA Mobility Unit (EMU), all variations of

  1. Development of an EVA systems cost model. Volume 2: Shuttle orbiter crew and equipment translation concepts and EVA workstation concept development and integration

    NASA Technical Reports Server (NTRS)

    1975-01-01

    EVA crewman/equipment translational concepts are developed for a shuttle orbiter payload application. Also considered are EVA workstation systems to meet orbiter and payload requirements for integration of workstations into candidate orbiter payload worksites.

  2. Crystalline imide/arylene ether copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor); Bass, Robert G. (Inventor)

    1995-01-01

    Crystalline imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly)arylene ethers) in polar aprotic solvents and chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The block copolymers of the invention have one glass transition temperature or two, depending on the particular structure and/or the compatibility of the block units. Most of these crystalline block copolymers for tough, solvent resistant films with high tensile properties. While all of the copolymers produced by the present invention are crystalline, testing reveals that copolymers with longer imide blocks or higher imide content have increased crystallinity.

  3. Collaborative Human Engineering Work in Space Exploration Extravehicular Activities (EVA)

    NASA Technical Reports Server (NTRS)

    DeSantis, Lena; Whitmore, Mihriban

    2007-01-01

    A viewgraph presentation on extravehicular activities in space exploration in collaboration with other NASA centers, industries, and universities is shown. The topics include: 1) Concept of Operations for Future EVA activities; 2) Desert Research and Technology Studies (RATS); 3) Advanced EVA Walkback Test; 4) Walkback Subjective Results; 5) Integrated Suit Test 1; 6) Portable Life Support Subsystem (PLSS); 7) Flex PLSS Design Process; and 8) EVA Information System; 9)

  4. Ulipristal acetate versus leuprolide acetate for uterine fibroids.

    PubMed

    Donnez, Jacques; Tomaszewski, Janusz; Vázquez, Francisco; Bouchard, Philippe; Lemieszczuk, Boguslav; Baró, Francesco; Nouri, Kazem; Selvaggi, Luigi; Sodowski, Krzysztof; Bestel, Elke; Terrill, Paul; Osterloh, Ian; Loumaye, Ernest

    2012-02-02

    The efficacy and side-effect profile of ulipristal acetate as compared with those of leuprolide acetate for the treatment of symptomatic uterine fibroids before surgery are unclear. In this double-blind noninferiority trial, we randomly assigned 307 patients with symptomatic fibroids and excessive uterine bleeding to receive 3 months of daily therapy with oral ulipristal acetate (at a dose of either 5 mg or 10 mg) or once-monthly intramuscular injections of leuprolide acetate (at a dose of 3.75 mg). The primary outcome was the proportion of patients with controlled bleeding at week 13, with a prespecified noninferiority margin of -20%. Uterine bleeding was controlled in 90% of patients receiving 5 mg of ulipristal acetate, in 98% of those receiving 10 mg of ulipristal acetate, and in 89% of those receiving leuprolide acetate, for differences (as compared with leuprolide acetate) of 1.2 percentage points (95% confidence interval [CI], -9.3 to 11.8) for 5 mg of ulipristal acetate and 8.8 percentage points (95% CI, 0.4 to 18.3) for 10 mg of ulipristal acetate. Median times to amenorrhea were 7 days for patients receiving 5 mg of ulipristal acetate, 5 days for those receiving 10 mg of ulipristal acetate, and 21 days for those receiving leuprolide acetate. Moderate-to-severe hot flashes were reported for 11% of patients receiving 5 mg of ulipristal acetate, for 10% of those receiving 10 mg of ulipristal acetate, and for 40% of those receiving leuprolide acetate (P<0.001 for each dose of ulipristal acetate vs. leuprolide acetate). Both the 5-mg and 10-mg daily doses of ulipristal acetate were noninferior to once-monthly leuprolide acetate in controlling uterine bleeding and were significantly less likely to cause hot flashes. (Funded by PregLem; ClinicalTrials.gov number, NCT00740831.).

  5. Diffusion of copolymers composed of monomers with drastically different friction factors in copolymer/homopolymer blends

    DOE PAGES

    Duranty, Edward R.; Baschnagel, Jörg; Dadmun, Mark

    2017-02-07

    Copolymers are commonly used as interface modifiers that allow for the compatibilization of polymer components in a blend. For copolymers to function as a compatibilizer, they must diffuse through the matrix of the blend to the interface between the two blend components. The diffusivity of a copolymer in a blend matrix therefore becomes important in determining good candidates for use as compatibilizers. In this paper, coarse-grained Monte Carlo simulations using the bond fluctuation model modified with an overlap penalty have been developed to study the diffusive behavior of PS/PMMA random copolymers in a PMMA homopolymer blend. The simulations vary themore » connectivity between different monomers, the thermodynamic interactions between the monomers which manifest within a chain, and between copolymer and homopolymer matrix and define the monomer friction coefficient of each component independently, allowing for the determination of the combined effect of these parameters on copolymer chain diffusion. Finally, the results of this work indicate that PS-r-PMMA copolymer diffusion is not linearly dependent on the copolymer composition on a logarithmic scale, but its diffusion is a balance of the kinetics governed by the dominant motion of the faster styrene monomers and thermodynamics, which are governed by the concentration of styrene monomer within a given monomer’s local volume.« less

  6. STS-64 extravehicular activity (EVA) hardware view

    NASA Image and Video Library

    1993-01-21

    S93-26918 (8 Sept. 1994) --- Scott Bleisath, an extravehicular activity (EVA) engineer, demonstrates the hand control module for the Simplified Aid for EVA Rescue (SAFER) system making its first flight on the scheduled September STS-64 mission. Astronauts Mark C. Lee and Carl J. Meade are the spacewalkers assigned to test the system in space. Unidentified technicians and engineers look on. Photo credit: NASA or National Aeronautics and Space Administration

  7. A Novel Recombinant Enterovirus Type EV-A89 with Low Epidemic Strength in Xinjiang, China

    PubMed Central

    Fan, Qin; Zhang, Yong; Hu, Lan; Sun, Qiang; Cui, Hui; Yan, Dongmei; Sikandaner, Huerxidan; Tang, Haishu; Wang, Dongyan; Zhu, Zhen; Zhu, Shuangli; Xu, Wenbo

    2015-01-01

    Enterovirus A89 (EV-A89) is a novel member of the EV-A species. To date, only one full-length genome sequence (the prototype strain) has been published. Here, we report the molecular identification and genomic characterization of a Chinese EV-A89 strain, KSYPH-TRMH22F/XJ/CHN/2011, isolated in 2011 from a contact of an acute flaccid paralysis (AFP) patient during AFP case surveillance in Xinjiang China. This was the first report of EV-A89 in China. The VP1 coding sequence of this strain demonstrated 93.2% nucleotide and 99.3% amino acid identity with the EV-A89 prototype strain. In the P2 and P3 regions, the Chinese EV-A89 strain demonstrated markedly higher identity than the prototype strains of EV-A76, EV-A90, and EV-A91, indicating that one or more recombination events between EV-A89 and these EV-A types might have occurred. Long-term evolution of these EV types originated from the same ancestor provides the spatial and temporal circumstances for recombination to occur. An antibody sero-prevalence survey against EV-A89 in two Xinjiang prefectures demonstrated low positive rates and low titres of EV-A89 neutralization antibody, suggesting limited range of transmission and exposure to the population. This study provides a solid foundation for further studies on the biological and pathogenic properties of EV-A89. PMID:26685900

  8. A Novel Recombinant Enterovirus Type EV-A89 with Low Epidemic Strength in Xinjiang, China.

    PubMed

    Fan, Qin; Zhang, Yong; Hu, Lan; Sun, Qiang; Cui, Hui; Yan, Dongmei; Sikandaner, Huerxidan; Tang, Haishu; Wang, Dongyan; Zhu, Zhen; Zhu, Shuangli; Xu, Wenbo

    2015-12-21

    Enterovirus A89 (EV-A89) is a novel member of the EV-A species. To date, only one full-length genome sequence (the prototype strain) has been published. Here, we report the molecular identification and genomic characterization of a Chinese EV-A89 strain, KSYPH-TRMH22F/XJ/CHN/2011, isolated in 2011 from a contact of an acute flaccid paralysis (AFP) patient during AFP case surveillance in Xinjiang China. This was the first report of EV-A89 in China. The VP1 coding sequence of this strain demonstrated 93.2% nucleotide and 99.3% amino acid identity with the EV-A89 prototype strain. In the P2 and P3 regions, the Chinese EV-A89 strain demonstrated markedly higher identity than the prototype strains of EV-A76, EV-A90, and EV-A91, indicating that one or more recombination events between EV-A89 and these EV-A types might have occurred. Long-term evolution of these EV types originated from the same ancestor provides the spatial and temporal circumstances for recombination to occur. An antibody sero-prevalence survey against EV-A89 in two Xinjiang prefectures demonstrated low positive rates and low titres of EV-A89 neutralization antibody, suggesting limited range of transmission and exposure to the population. This study provides a solid foundation for further studies on the biological and pathogenic properties of EV-A89.

  9. Generic extravehicular (EVA) and telerobot task primitives for analysis, design, and integration. Version 1.0: Reference compilation for the EVA and telerobotics communities

    NASA Technical Reports Server (NTRS)

    Smith, Jeffrey H.; Drews, Michael

    1990-01-01

    The results are described of an effort to establish commonality and standardization of generic crew extravehicular (crew-EVA) and telerobotic task analysis primitives used for the study of spaceborne operations. Although direct crew-EVA plans are the most visible output of spaceborne operations, significant ongoing efforts by a wide variety of projects and organizations also require tools for estimation of crew-EVA and telerobotic times. Task analysis tools provide estimates for input to technical and cost tradeoff studies. A workshop was convened to identify the issues and needs to establish a common language and syntax for task analysis primitives. In addition, the importance of such a syntax was shown to have precedence over the level to which such a syntax is applied. The syntax, lists of crew-EVA and telerobotic primitives, and the data base in diskette form are presented.

  10. Bilateral Sequential Cochlear Implantation in Patients With Enlarged Vestibular Aqueduct (EVA) Syndrome.

    PubMed

    Manzoor, Nauman F; Wick, Cameron C; Wahba, Marian; Gupta, Amit; Piper, Robin; Murray, Gail S; Otteson, Todd; Megerian, Cliff A; Semaan, Maroun T

    2016-02-01

    To analyze audiometric outcomes after bilateral cochlear implantation in patients with isolated enlarged vestibular aqueduct (EVA) syndrome and associated incomplete partition (IP) malformations. Secondary objective was to analyze rate of cerebrospinal fluid (CSF) gusher in patients with IP-EVA spectrum deformities and compare this with the existing literature. Retrospective chart review. Thirty-two patients with EVA syndrome who received unilateral or bilateral cochlear implants between June 1999 and January 2014 were identified in the University Hospitals Case Medical Center cochlear implant database. Isolated EVA (IEVA) and Incomplete Partition Type II (IP-II) malformations were identified by reviewing high-resolution computed tomography (HRCT) imaging. Demographic information, age at implantation, surgical details, postimplantation audiometric data including speech reception thresholds (SRT), word, and sentence scores were reviewed and analyzed. Intra- and postoperative complications were analyzed as well and compared with the literature. Seventeen patients (32 implanted ears) had pediatric cochlear implantation for EVA-associated hearing loss. Data from 16 controls (32 implanted ears) were used to compare audiometric and speech outcomes of EVA cohort. Mean age at implantation was 6.8 years for EVA cohort and 6.0 years for controls. There was no statistically significant difference in long-term postoperative SRT, monaurally aided word scores, and binaurally tested word scores between pediatric EVA group and controls. The EVA patients had a long-term mean sentence score of 85.92%. A subset of EVA patients implanted at mean age of 3.18 years (n = 15 ears) had similar audiometric outcomes to another control group with Connexin 26 mutations (n = 20 ears) implanted at a similar age. Further subset analysis revealed no significant differences in age at implantation, SRT, and word scores in patients with IEVA and IP-II malformation. There was no significant

  11. EVA view taken during STS-102

    NASA Image and Video Library

    2001-03-11

    STS102-312-004 (11 March 2001) --- Astronaut James S. Voss works while anchored to the remote manipulator system (RMS) robot arm on the Space Shuttle Discovery. This extravehicular activity (EVA), on which Voss was joined by astronaut Susan J. Helms (out of frame), was the first of two scheduled STS-102 space walks. The pair, destined to become members of the Expedition Two crew aboard the station later in the mission, rode aboard Discovery into orbit and at the time of this EVA were still regarded as STS-102 mission specialists.

  12. Effect of TiO2-Crystal Forms on the Photo-Degradation of EVA/PLA Blend Under Accelerated Weather Testing

    NASA Astrophysics Data System (ADS)

    Van Cong, Do; Trang, Nguyen Thi Thu; Giang, Nguyen Vu; Lam, Tran Dai; Hoang, Thai

    2016-05-01

    Photo-degradation of poly (ethylene-co-vinyl acetate) (EVA)/poly (lactic acid) (PLA) blend and EVA/PLA/TiO2 nanocomposites was carried out under accelerated weather testing conditions by alternating cycles of ultraviolet (UV) light and moisture at controlled and elevated temperatures. The characters, properties, and morphology of these materials before and after accelerated weather testing were determined by Fourier transform infrared spectroscopy, colour changes, viscosity, tensile test, thermogravimetric analysis, and field emission scanning electron microscopy. The increases in the content of oxygen-containing groups, colour changes; the decreases in viscosity, tensile properties, and thermal stability of these materials after accelerated weather testing are the evidence for the photo-degradation of the blend and nanocomposites. After accelerated weather testing, the appearance of many micro-holes and micro-pores on the surface of the collected samples was observed. The photo-degradation degree of the nanocomposites depended on the TiO2-crystal form. Rutile TiO2 do not enhance the degradation, but anatase and mixed crystals TiO2 nanoparticles promoted the degradation of the nanocomposites. Particularly, the mixed crystals TiO2 nanoparticles showed the highest photo-catalytic activity of the nanocomposites.

  13. The role of EVA on Space Shuttle. [experimental support and maintenance activities

    NASA Technical Reports Server (NTRS)

    Carson, M. A.

    1974-01-01

    The purpose of this paper is to present the history of Extravehicular Activity (EVA) through the Skylab Program and to outline the expected tasks and equipment capabilities projected for the Space Shuttle Program. Advantages offered by EVA as a tool to extend payload capabilities and effectiveness and economic advantages of using EVA will be explored. The presentation will conclude with some guidelines and recommendations for consideration by payload investigators in establishing concepts and designs utilizing EVA support.

  14. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035256 (22 Aug. 2013) --- Russian cosmonauts Alexander Misurkin (top) and Fyodor Yurchikhin, both Expedition 36 flight engineers, are pictured in the Zvezda Service Module of the International Space Station following a session of extravehicular activity (EVA). Misurkin and Yurchikhin are wearing blue thermal undergarments that complement the Russian Orlan spacesuit.

  15. Distribution of short block copolymer chains in Binary Blends of Block Copolymers Having Hydrogen Bonding

    NASA Astrophysics Data System (ADS)

    Kwak, Jongheon; Han, Sunghyun; Kim, Jin Kon

    2014-03-01

    A binary mixture of two block copolymers whose blocks are capable of forming the hydrogen bonding allows one to obtain various microdomains that could not be expected for neat block copolymer. For instance, the binary blend of symmetric polystyrene-block-poly(2-vinylpyridine) copolymer (PS-b-P2VP) and polystyrene-block-polyhydroxystyrene copolymer (PS-b-PHS) blends where the hydrogen bonding occurred between P2VP and PHS showed hexagonally packed (HEX) cylindrical and body centered cubic (BCC) spherical microdomains. To know the exact location of short block copolymer chains at the interface, we synthesized deuterated polystyrene-block-polyhydroxystyrene copolymer (dPS-b-PHS) and prepared a binary mixture with PS-b-P2VP. We investigate, via small angle X-ray scattering (SAXS) and neutron reflectivity (NR), the exact location of shorter dPS block chain near the interface of the microdomains.

  16. CETA truck and EVA restraint system

    NASA Technical Reports Server (NTRS)

    Beals, David C.; Merson, Wayne R.

    1991-01-01

    The Crew Equipment Translation Aid (CETA) experiment is an extravehicular activity (EVA) Space Transportation System (STS) based flight experiment which will explore various modes of transporting astronauts and light equipment for Space Station Freedom (SSF). The basic elements of CETA are: (1) two 25 foot long sections of monorail, which will be EVA assembled in the STS cargo bay to become a single 50 ft. rail called the track; (2) a wheeled baseplate called the truck which rolls along the track and can accept three cart concepts; and (3) the three carts which are designated manual, electric, and mechanical. The three carts serve as the astronaut restraint and locomotive interfaces with the track. The manual cart is powered by the astronaut grasping the track's handrail and pulling himself along. The electric cart is operated by an astronaut turning a generator which powers the electric motor and drives the cart. The mechanical cart is driven by a Bendix type transmission and is similar in concept to a man-propelled railroad cart. During launch and landing, the truck is attached to the deployable track by means of EVA removable restraint bolts and held in position by a system of retractable shims. These shims are positioned on the exterior of the rail for launch and landing and rotate out of the way for the duration of the experiment. The shims are held in position by strips of Velcro nap, which rub against the sides of the shim and exert a tailored force. The amount of force required to rotate the shims was a major EVA concern, along with operational repeatability and extreme temperature effects. The restraint system was tested in a thermal-vac and vibration environment and was shown to meet all of the initial design requirements. Using design inputs from the astronauts who will perform the EVA, CETA evolved through an iterative design process and represented a cooperative effort.

  17. Activity during first EVA of STS-72 mission

    NASA Image and Video Library

    1996-01-15

    STS072-305-034 (15 Jan. 1996) --- Astronaut Daniel T. Barry, mission specialist, works in the cargo bay of the Space Shuttle Endeavour during the first of two extravehicular activities (EVA). Barry was joined by astronaut Leroy Chiao for the EVA. The two joined four other NASA astronauts for a week and a half aboard Endeavour.

  18. Knockout of Eva1a leads to rapid development of heart failure by impairing autophagy

    PubMed Central

    Zhang, Shu; Lin, Xin; Li, Ge; Shen, Xue; Niu, Di; Lu, Guang; Fu, Xin; Chen, Yingyu; Cui, Ming; Bai, Yun

    2017-01-01

    EVA1A (Eva-1 homologue A) is a novel lysosome and endoplasmic reticulum-associated protein that can regulate cell autophagy and apoptosis. Eva1a is expressed in the myocardium, but its function in myocytes has not yet been investigated. Therefore, we generated inducible, cardiomyocyte-specific Eva1a knockout mice with an aim to determine the role of Eva1a in cardiac remodelling in the adult heart. Data from experiments showed that loss of Eva1a in the adult heart increased cardiac fibrosis, promoted cardiac hypertrophy, and led to cardiomyopathy and death. Further investigation suggested that this effect was associated with impaired autophagy and increased apoptosis in Eva1a knockout hearts. Moreover, knockout of Eva1a activated Mtor signalling and the subsequent inhibition of autophagy. In addition, Eva1a knockout hearts showed disorganized sarcomere structure and mitochondrial misalignment and aggregation, leading to the lack of ATP generation. Collectively, these data demonstrated that Eva1a improves cardiac function and inhibits cardiac hypertrophy and fibrosis by increasing autophagy. In conclusion, our results demonstrated that Eva1a may have an important role in maintaining cardiac homeostasis. PMID:28151473

  19. Imide/arylene ether copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J. (Inventor); Hergenrother, Paul M. (Inventor); Bass, Robert G. (Inventor)

    1992-01-01

    Imide/arylene ether block copolymers are prepared by reacting anhydride terminated poly(amic acids) with amine terminated poly(arylene ethers) in polar aprotic solvents and by chemically or thermally cyclodehydrating the resulting intermediate poly(amic acids). The resulting block copolymers have one glass transition temperature or two, depending upon the particular structure and/or the compatibility of the block units. Most of these block copolymers form tough, solvent resistant films with high tensile properties.

  20. EVA: laparoscopic instrument tracking based on Endoscopic Video Analysis for psychomotor skills assessment.

    PubMed

    Oropesa, Ignacio; Sánchez-González, Patricia; Chmarra, Magdalena K; Lamata, Pablo; Fernández, Alvaro; Sánchez-Margallo, Juan A; Jansen, Frank Willem; Dankelman, Jenny; Sánchez-Margallo, Francisco M; Gómez, Enrique J

    2013-03-01

    The EVA (Endoscopic Video Analysis) tracking system is a new system for extracting motions of laparoscopic instruments based on nonobtrusive video tracking. The feasibility of using EVA in laparoscopic settings has been tested in a box trainer setup. EVA makes use of an algorithm that employs information of the laparoscopic instrument's shaft edges in the image, the instrument's insertion point, and the camera's optical center to track the three-dimensional position of the instrument tip. A validation study of EVA comprised a comparison of the measurements achieved with EVA and the TrEndo tracking system. To this end, 42 participants (16 novices, 22 residents, and 4 experts) were asked to perform a peg transfer task in a box trainer. Ten motion-based metrics were used to assess their performance. Construct validation of the EVA has been obtained for seven motion-based metrics. Concurrent validation revealed that there is a strong correlation between the results obtained by EVA and the TrEndo for metrics, such as path length (ρ = 0.97), average speed (ρ = 0.94), or economy of volume (ρ = 0.85), proving the viability of EVA. EVA has been successfully validated in a box trainer setup, showing the potential of endoscopic video analysis to assess laparoscopic psychomotor skills. The results encourage further implementation of video tracking in training setups and image-guided surgery.

  1. U.S. Exploration EVA: ConOps, Interfaces and Test Objectives for Airlocks

    NASA Technical Reports Server (NTRS)

    Buffington, J.

    2017-01-01

    NASA is moving forward on defining the xEVA System Architecture and its implications to the spacecraft that host exploration EVA systems. This presentation provides an overview of the latest information for NASA's Concept of Operations (ConOps), Interfaces and corresponding Test Objectives for Airlocks hosting the xEVA System.

  2. EVA 27

    NASA Image and Video Library

    2014-10-07

    ISS041-E-067002 (7 Oct. 2014) --- NASA astronaut Reid Wiseman, Expedition 41 flight engineer, participates in a session of extravehicular activity (EVA) as work continues on the International Space Station. During the six-hour, 13-minute spacewalk, Wiseman and European Space Agency astronaut Alexander Gerst (out of frame), flight engineer, worked outside the space station's Quest airlock relocating a failed cooling pump to external stowage and installing gear that provides back up power to external robotics equipment.

  3. Payload bay activity during second EVA of STS-72 mission

    NASA Image and Video Library

    1996-01-16

    STS072-393-008 (17 Jan. 1996) --- Astronaut Leroy Chiao gives a thumbs up signal, marking the success of his second extravehicular activity (EVA) in three days. Chiao was joined by astronaut Winston E. Scott on this EVA.

  4. Astronaut Jack Lousma seen outside Skylab space station during EVA

    NASA Image and Video Library

    1973-08-06

    S73-31976 (5 Aug. 1973) --- Astronaut Jack R. Lousma, Skylab 3 pilot, is seen outside the Skylab space station in Earth orbit during the Aug. 5, 1973 Skylab 3 extravehicular activity (EVA) in this photographic reproduction taken from a television transmission made by a color TV camera aboard the space station. Scientist-astronaut Owen K. Garriott, Skylab 3 science pilot, participated in the EVA with Lousma. During the EVA the two crewmen deployed the twin pole solar shield to help shade the Orbital Workshop. Photo credit: NASA

  5. Hydrogen-bonded aggregates in precise acid copolymers

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lueth, Christopher A.; Bolintineanu, Dan S.; Stevens, Mark J., E-mail: msteve@sandia.gov

    2014-02-07

    We perform atomistic molecular dynamics simulations of melts of four precise acid copolymers, two poly(ethylene-co-acrylic acid) (PEAA) copolymers, and two poly(ethylene-co-sulfonic acid) (PESA) copolymers. The acid groups are spaced by either 9 or 21 carbons along the polymer backbones. Hydrogen bonding causes the acid groups to form aggregates. These aggregates give rise to a low wavevector peak in the structure factors, in agreement with X-ray scattering data for the PEAA materials. The structure factors for the PESA copolymers are very similar to those for the PEAA copolymers, indicating a similar distance between aggregates which depends on the spacer length butmore » not on the nature of the acid group. The PEAA copolymers are found to form more dimers and other small aggregates than do the PESA copolymers, while the PESA copolymers have both more free acid groups and more large aggregates.« less

  6. Curbeen during first EVA

    NASA Image and Video Library

    2006-12-13

    ISS014-E-09523 (12 Dec. 2006) --- Astronaut Robert L. Curbeam, Jr., STS-116 mission specialist, participates in the mission's first of three planned sessions of extravehicular activity (EVA) as construction resumes on the International Space Station. A power tool, attached to Curbeam's spacesuit, floats at left.

  7. The main results of EVA medical support on the Mir Space Station

    NASA Astrophysics Data System (ADS)

    Katuntsev, V. P.; Osipov, Yu. Yu.; Barer, A. S.; Gnoevaya, N. K.; Tarasenkov, G. G.

    2004-04-01

    The aim of this paper is to review the main results of medical support of 78 two-person extravehicular activities (EVAs) which have been conducted in the Mir Space Program. Thirty-six male crewmembers participated in these EVAs. Maximum length of a space walk was equal to 7 h 14 min. The total duration of all space walks reached 717.1 man-hours. The maximum frequency of EVA's execution was 10 per year. Most of the EVAs (67) have been performed at mission elapsed time ranging from 31 to 180 days. The oxygen atmosphere of the Orlan space suit with a pressure of 40 kPa in combination with the normobaric cabin environment and a short (30 min) oxygen prebreathe protocol have minimized the risk of decompression sickness (DCS). There has been no incidence of DCS during performed EVAs. At the peak activity, metabolic rates and heart rates increased up to 9.9- 13 kcal/ min and 150- 174 min-1, respectively. The medical problems have centred on feeling of moderate overcooling during a rest period in a shadow after the high physical loads, episodes with tachycardia accompanied by cardiac rhythm disorders at the moments of emotional stress, pains in the muscles and general fatigue after the end of a hard EVA. All of the EVAs have been completed safely.

  8. The main results of EVA medical support on the Mir Space Station.

    PubMed

    Katuntsev, V P; Osipov, Yu Yu; Barer, A S; Gnoevaya, N K; Tarasenkov, G G

    2004-04-01

    The aim of this paper is to review the main results of medical support of 78 two-person extravehicular activities (EVAs) which have been conducted in the Mir Space Program. Thirty-six male crewmembers participated in these EVAs. Maximum length of a space walk was equal to 7 h 14 min. The total duration of all space walks reached 717.1 man-hours. The maximum frequency of EVA's execution was 10 per year. Most of the EVAs (67) have been performed at mission elapsed time ranging from 31 to 180 days. The oxygen atmosphere of the Orlan space suit with a pressure of 40 kPa in combination with the normobaric cabin environment and a short (30 min) oxygen prebreathe protocol have minimized the risk of decompression sickness (DCS). There has been no incidence of DCS during performed EVAs. At the peak activity, metabolic rates and heart rates increased up to 9.9-13 kcal/min and 150-174 min-1, respectively. The medical problems have centred on feeling of moderate overcooling during a rest period in a shadow after the high physical loads, episodes with tachycardia accompanied by cardiac rhythm disorders at the moments of emotional stress, pains in the muscles and general fatigue after the end of a hard EVA. All of the EVAs have been completed safely. c2003 Elsevier Ltd. All rights reserved.

  9. Design, development and evaluation of Stanford/Ames EVA prehensors

    NASA Technical Reports Server (NTRS)

    Leifer, Larry J.; Aldrich, J.; Leblanc, M.; Sabelman, E.; Schwandt, D.

    1988-01-01

    Space Station operations and maintenance are expected to make unprecedented demands on astronaut EVA. With Space Station expected to operate with an 8 to 10 psi atmosphere (4 psi for Shuttle operations), the effectivness of pressurized gloves is called into doubt at the same time that EVA activity levels are to be increased. To address the need for more frequent and complex EVA missions and also to extend the dexterity, duration, and safety of EVA astronauts, NASA Ames and Stanford University have an ongoing cooperative agreement to explore and compare alternatives. This is the final Stanford/Ames report on manually powered Prehensors, each of which consists of a shroud forming a pressure enclosure around the astronaut's hand, and a linkage system to transfer the motions and forces of the hand to mechanical digits attached to the shroud. All prehensors are intended for attachment to a standard wrist coupling, as found on the AX-5 hard suit prototype, so that realistic tests can be performed under normal and reduced gravity as simulated by water flotation.

  10. Active personal radiation monitor for lunar EVA

    NASA Astrophysics Data System (ADS)

    Straume, Tore; Borak, Tom; Braby, L. A.; Lusby, Terry; Semones, Edward J.; Vazquez, Marcelo E.

    As astronauts return to the Moon-and this time, work for extended periods-there will be a critical need for crew personnel radiation monitoring as they operate lunar rovers or otherwise perform a myriad of extravehicular activities (EVAs). Our focus is on development of a small personal radiation monitor for lunar EVA that responds to the complex radiation quality and changing dose rates on the Moon. Of particular concern are active monitoring capabilities that provide both early warning and radiation dosimetry information during solar particle events (SPEs). To accomplish this, we are developing small detectors integrated with modern high speed, low power microelectronics to measure dose-rate and dose-mean lineal energy in real time. The monitor is designed to perform over the range of dose rates and LETs expected from both GCR and SPE radiations during lunar EVA missions. The monitor design provides simultaneous measurement of dose-equivalent rates at two tissue-equivalent depths simulating skin and marrow. The compact personal monitor is estimated to be the size of a cell phone and would fit on an EVA spacesuit (e.g., in backpack) or in a toolbox. The four-year development effort (which began December 2007) will result in a prototype radiation monitor field tested and characterized for the major radiations expected on the surface of the Moon. We acknowledge support from NSBRI through grants to NASA Ames Research Center (T. Straume, PI) and Colorado State University (T. Borak, PI).

  11. Human Space Exploration and Radiation Exposure from EVA: 1981-2011

    NASA Astrophysics Data System (ADS)

    Way, A. R.; Saganti, S. P.; Erickson, G. M.; Saganti, P. B.

    2011-12-01

    There are several risks for any human space exploration endeavor. One such inevitable risk is exposure to the space radiation environment of which extra vehicular activity (EVA) demands more challenges due to limited amount of protection from space suit shielding. We recently compiled all EVA data comprising low-earth orbit (LEO) from Space Shuttle (STS) flights, International Space Station (ISS) expeditions, and Shuttle-Mir missions. Assessment of such radiation risk is very important, particularly for the anticipated long-term, deep-space human explorations in the near future. We present our assessment of anticipated radiation exposure and space radiation dose contribution to each crew member from a listing of 350 different EVA events resulting in more than 1000+ hrs of total EVA time. As of July 12, 2011, 197 astronauts have made spacewalks (out of 520 people who have gone into Earth orbit). Only 11 women have been on spacewalks.

  12. Compiling a Comprehensive EVA Training Dataset for NASA Astronauts

    NASA Technical Reports Server (NTRS)

    Laughlin, M. S.; Murry, J. D.; Lee, L. R.; Wear, M. L.; Van Baalen, M.

    2016-01-01

    Training for a spacewalk or extravehicular activity (EVA) is considered hazardous duty for NASA astronauts. This activity places astronauts at risk for decompression sickness as well as various musculoskeletal disorders from working in the spacesuit. As a result, the operational and research communities over the years have requested access to EVA training data to supplement their studies.

  13. Astronaut Musgrave performing EVA during STS-6

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Views of Mission Specialist F. Story Musgrave performing an extravehicular activity (EVA) during the STS-6 mission. In this view, Musgrave uses hand holds in the payload bay door hinge line to move towards the aft payload bay (30215); Musgrave conducts a simulation of a contingency EVA in the aft payload bay. This was designed to return the inertial upper stage (IUS) support equipment's tilt table device to its normal stowed configuration in the event of failure of an automatic system. A cloud-covered earth can be seen in the background (30216).

  14. New Polytetrahydrofuran Graft Copolymers.

    DTIC Science & Technology

    1979-03-15

    chioroprene) , chiorobutyl - ~~~~~ rubber , bromobutyl rubber , chlorinated EPDM , chlorinated poly(buta— diene) and chlorinated butadiene styrene copolymer...bromobutyl rubber , which after dehalogenation is unstable with respect to conjugated dienes, the yields of graft copolymer are low. With poly(chloroprerte

  15. Phase Behavior of Neat Triblock Copolymers and Copolymer/Homopolymer Blends Near Network Phase Windows

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    M Tureau; L Rong; B Hsiao

    The phase behavior of poly(isoprene-b-styrene-b-methyl methacrylate) (ISM) copolymers near the styrene-rich network phase window was examined through the use of neat triblock copolymers and copolymer/homopolymer blends. Both end-block and middle-block blending protocols were employed using poly(isoprene) (PI), poly(methyl methacrylate) (PMMA), and poly(styrene) (PS) homopolymers. Blended specimens exhibited phase transformations to well-ordered nanostructures (at homopolymer loadings up to 26 vol % of the total blend volume). Morphological consistency between neat and blended specimens was established at various locations in the ISM phase space. Copolymer/homopolymer blending permitted the refinement of lamellar, hexagonally packed cylinder, and disordered melt phase boundaries as well asmore » the identification of double gyroid (Q{sup 230}), alternating gyroid (Q{sup 214}), and orthorhombic (O{sup 70}) network regimes. Additionally, the experimental phase diagram exhibited similar trends to those found in a theoretical ABC triblock copolymer phase diagram with symmetric interactions and statistical segments lengths generated by Tyler et al.« less

  16. TEJAS - TELEROBOTICS/EVA JOINT ANALYSIS SYSTEM VERSION 1.0

    NASA Technical Reports Server (NTRS)

    Drews, M. L.

    1994-01-01

    The primary objective of space telerobotics as a research discipline is the augmentation and/or support of extravehicular activity (EVA) with telerobotic activity; this allows increased emplacement of on-orbit assets while providing for their "in situ" management. Development of the requisite telerobot work system requires a well-understood correspondence between EVA and telerobotics that to date has been only partially established. The Telerobotics/EVA Joint Analysis Systems (TEJAS) hypermedia information system uses object-oriented programming to bridge the gap between crew-EVA and telerobotics activities. TEJAS Version 1.0 contains twenty HyperCard stacks that use a visual, customizable interface of icon buttons, pop-up menus, and relational commands to store, link, and standardize related information about the primitives, technologies, tasks, assumptions, and open issues involved in space telerobot or crew EVA tasks. These stacks are meant to be interactive and can be used with any database system running on a Macintosh, including spreadsheets, relational databases, word-processed documents, and hypermedia utilities. The software provides a means for managing volumes of data and for communicating complex ideas, relationships, and processes inherent to task planning. The stack system contains 3MB of data and utilities to aid referencing, discussion, communication, and analysis within the EVA and telerobotics communities. The six baseline analysis stacks (EVATasks, EVAAssume, EVAIssues, TeleTasks, TeleAssume, and TeleIssues) work interactively to manage and relate basic information which you enter about the crew-EVA and telerobot tasks you wish to analyze in depth. Analysis stacks draw on information in the Reference stacks as part of a rapid point-and-click utility for building scripts of specific task primitives or for any EVA or telerobotics task. Any or all of these stacks can be completely incorporated within other hypermedia applications, or they can be

  17. EVA Performance Prediction

    NASA Technical Reports Server (NTRS)

    Peacock, Brian; Maida, James; Rajulu, Sudhakar

    2004-01-01

    Astronaut physical performance capabilities in micro gravity EV A or on planetary surfaces when encumbered by a life support suit and debilitated by a long exposure to micro gravity will be less than unencumbered pre flight capabilities. The big question addressed by human factors engineers is: what can the astronaut be expected to do on EVA or when we arrive at a planetary surface? A second question is: what aids to performance will be needed to enhance the human physical capability? These questions are important for a number of reasons. First it is necessary to carry out accurate planning of human physical demands to ensure that time and energy critical tasks can be carried out with confidence. Second it is important that the crew members (and their ground or planetary base monitors) have a realistic picture of their own capabilities, as excessive fatigue can lead to catastrophic failure. Third it is important to design appropriate equipment to enhance human sensory capabilities, locomotion, materials handling and manipulation. The evidence from physiological research points to musculoskeletal, cardiovascular and neurovestibular degradation during long duration exposure to micro gravity . The evidence from the biomechanics laboratory (and the Neutral Buoyancy Laboratory) points to a reduction in range of motion, strength and stamina when encumbered by a pressurized suit. The evidence from a long history of EVAs is that crewmembers are indeed restricted in their physical capabilities. There is a wealth of evidence in the literature on the causes and effects of degraded human performance in the laboratory, in sports and athletics, in industry and in other physically demanding jobs. One approach to this challenge is through biomechanical and performance modeling. Such models must be based on thorough task analysis, reliable human performance data from controlled studies, and functional extrapolations validated in analog contexts. The task analyses currently carried

  18. The Potential of Wearable Sensor Technology for EVA Glove Ergonomic Evaluation

    NASA Technical Reports Server (NTRS)

    Reid, Christopher R.; McFarland, Shane M.; Norcross, Jason R.; Rajulu, Sudhakar

    2014-01-01

    Injuries to the hands are common among astronauts who train for extravehicular activity (EVA). Many of these injuries refer to the gloves worn during EVA as the root cause. While pressurized, the bladder and outer material of these gloves restrict movement and create pressure points while performing tasks, sometimes resulting in pain, muscle fatigue, abrasions, and occasionally a more severe injury, onycholysis (fingernail delamination). The most common injury causes are glove contact (pressure point/rubbing), ill-fitting gloves, and/or performing EVA tasks in pressurized gloves. A brief review of the Lifetime Surveillance of Astronaut Health's injury database reveals over 57% of the total injuries to the upper extremities during EVA training occurred either to the metacarpophalangeal (MCP) joint, fingernail, or the fingertip. Twenty-five of these injuries resulted in a diagnosis of onycholysis.

  19. The Potential of Wearable Sensor Technology for EVA Glove Ergonomic Evaluation

    NASA Technical Reports Server (NTRS)

    Reid, Christopher R.; McFarland, Shane; Norcross, Jason R.; Rajulu, Sudhakar

    2014-01-01

    Injuries to the hands are common among astronauts who train for extravehicular activity (EVA). Many of these injuries refer to the gloves worn during EVA as the root cause. While pressurized, the bladder and outer material of these gloves restrict movement and create pressure points while performing tasks, sometimes resulting in pain, muscle fatigue, abrasions, and occasionally a more severe injury, onycholysis (fingernail delamination). The most common injury causes are glove contact (pressure point/rubbing), ill-fitting gloves, and/or performing EVA tasks in pressurized gloves. A brief review of the Lifetime Surveillance of Astronaut Health's injury database reveals over 57% of the total injuries to the upper extremities during EVA training occurred either to the metacarpophalangeal (MCP) joint, fingernail, or the fingertip. Twenty-five of these injuries resulted in a diagnosis of onycholysis

  20. Astronaut Carl Walz during EVA in Discovery's payload bay

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Astronaut Carl E. Walz reaches for equipment from the provisional stowage assembly (PSA) in Discvoery's cargo bay during a lengthy period of extravehicular activity (EVA). The hatch to Discovery's airlock is open nearby. Sun glare is evident above the orbiter. The picture was taken with a 35mm camera by astronaut James H. Newman, who shared EVA duties with Walz.

  1. Molecular Interaction Control in Diblock Copolymer Blends and Multiblock Copolymers with Opposite Phase Behaviors

    NASA Astrophysics Data System (ADS)

    Cho, Junhan

    2014-03-01

    Here we show how to control molecular interactions via mixing AB and AC diblock copolymers, where one copolymer exhibits upper order-disorder transition and the other does lower disorder-order transition. Linear ABC triblock copolymers possessing both barotropic and baroplastic pairs are also taken into account. A recently developed random-phase approximation (RPA) theory and the self-consistent field theory (SCFT) for general compressible mixtures are used to analyze stability criteria and morphologies for the given systems. It is demonstrated that the copolymer systems can yield a variety of phase behaviors in their temperature and pressure dependence upon proper mixing conditions and compositions, which is caused by the delicate force fields generated in the systems. We acknowledge the financial support from National Research Foundation of Korea and Center for Photofunctional Energy Materials.

  2. Bicomponent Block Copolymers Derived from One or More Random Copolymers as an Alternative Route to Controllable Phase Behavior

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ashraf, Arman R.; Ryan, Justin J.; Satkowski, Michael M.

    Block copolymers have been extensively studied due to their ability to spontaneously self-organize into a wide variety of morphologies that are valuable in energy-, medical- and conservation-related (nano)technologies. While the phase behavior of bicomponent diblock and triblock copolymers is conventionally governed by temperature and individual block masses, we demonstrate that their phase behavior can alternatively be controlled through the use of blocks with random monomer sequencing. Block random copolymers (BRCs), i.e., diblock copolymers wherein one or both blocks is a random copolymer comprised of A and B repeat units, have been synthesized, and their phase behavior, expressed in terms ofmore » the order-disorder transition (ODT), has been investigated. Our results establish that, depending on the block composition contrast and molecular weight, BRCs can microphase-separate. We also report that the predicted ODT can be generated at relatively constant molecular weight and temperature with these new soft materials. This sequence-controlled synthetic strategy is extended to thermoplastic elastomeric triblock copolymers differing in chemistry and possessing a random-copolymer midblock.« less

  3. Russian EVA no. 39.

    NASA Image and Video Library

    2014-08-18

    ISS040E099355 (08/18/2014) --- Russian cosmonaut Alexander Skvortsov (red stripes), Expedition 40 flight engineer, attired in a Russian Orlan spacesuit outside the International Space Station, participates in a session of extravehicular activity (EVA) number 39 in support of science and maintenance. The Solar array is visible in the background.

  4. EVA Suit Microbial Leakage

    NASA Technical Reports Server (NTRS)

    Rucker, Michelle

    2016-01-01

    NASA has a strategic knowledge gap (B5-3) about what life signatures leak/vent from our Extravehicular Activity (EVA) systems. This will impact how we search for evidence of life on Mars. Characterizing contamination leaks from our suits will help us comply with planetary protection guidelines, and better plan human exploration missions.

  5. Microphase separation in random multiblock copolymers

    NASA Astrophysics Data System (ADS)

    Govorun, E. N.; Chertovich, A. V.

    2017-01-01

    Microphase separation in random multiblock copolymers is studied with the mean-field theory assuming that long blocks of a copolymer are strongly segregated, whereas short blocks are able to penetrate into "alien" domains and exchange between the domains and interfacial layer. A bidisperse copolymer with blocks of only two sizes (long and short) is considered as a model of multiblock copolymers with high polydispersity in the block size. Short blocks of the copolymer play an important role in the microphase separation. First, their penetration into the "alien" domains leads to the formation of joint long blocks in their own domains. Second, short blocks localized at the interface considerably change the interfacial tension. The possibility of penetration of short blocks into the "alien" domains is controlled by the product χ Nsh (χ is the Flory-Huggins interaction parameter and Nsh is the short block length). At not very large χ Nsh , the domain size is larger than that for a regular copolymer consisting of the same long blocks as in the considered random copolymer. At a fixed mean block size, the domain size grows with an increase in the block size dispersity, the rate of the growth being dependent of the more detailed parameters of the block size distribution.

  6. Carbon nanotube/poly(ethylene-co-vinyl acetate) composite electrode for capillary electrophoretic determination of esculin and esculetin in Cortex Fraxini.

    PubMed

    Chen, Zhi; Zhang, Luyan; Chen, Gang

    2009-10-01

    In this report, a novel carbon nanotube/poly(ethylene-co-vinyl acetate) (CNT/EVA) composite electrode was developed for the amperometric detection in CE. The composite electrode was fabricated by packing a mixture of CNTs and melted EVA in a piece of fused-silica capillary under heat. It was coupled with CE for the separation and detection of esculin and esculetin in Cortex Fraxini, a traditional Chinese medicine, to demonstrate its feasibility and performance. Esculin and esculetin have been well separated within 9 min in a 40 cm long capillary at a separation voltage of 12 kV using a 50 mM borate buffer (pH 9.2). The new CNT-based CE detector offered significantly lower detection potentials, yielded enhanced S/N characteristics, and exhibited high resistance to surface fouling and enhanced stability. It showed long-term stability and reproducibility with relative standard deviations of less than 5% for the peak current (n=15) and should also find a wide range of applications in other microfluidic analysis systems.

  7. Extravehicular Activity/Air Traffic Control (EVA/ATC) test report. [communication links to the astronaut

    NASA Technical Reports Server (NTRS)

    Tomaro, D. J.

    1982-01-01

    During extravehicular activity (EVA), communications between the EVA astronaut and the space shuttle orbiter are maintained by means of transceiver installed in the environmental support system backpack. Onboard the orbiter, a transceiver line replaceable unit and its associated equipment performs the task of providing a communications link to the astronaut in the extravehicular activity/air traffic control (EVA/ATC) mode. Results of the acceptance tests that performed on the system designed and fabricated for EVA/ATC testing are discussed.

  8. Cobalt-Mediated Radical Polymerization of Vinyl Acetate and Acrylonitrile in Supercritical Carbon Dioxide.

    PubMed

    Kermagoret, Anthony; Chau, Ngoc Do Quyen; Grignard, Bruno; Cordella, Daniela; Debuigne, Antoine; Jérôme, Christine; Detrembleur, Christophe

    2016-03-01

    Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO2). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is soluble in scCO2. Kinetics studies coupled to visual observations of the polymerization medium highlight that the melt viscosity and PVAc molar mass (Mn) are key parameters that affect the CMRP in scCO2. It is noticed that CMRP is controlled for Mn up to 10 000 g mol(-1), but loss of control is progressively observed for higher molar masses when PVAc precipitates in the polymerization medium. Low molar mass PVAc macroinitiator, prepared by CMRP in scCO2, is then successfully used to initiate the acrylonitrile polymerization. PVAc-b-PAN block copolymer is collected as a free flowing powder at the end of the process although the dispersity of the copolymer increases with the reaction time. Although optimization is required to decrease the dispersity of the polymer formed, this CMRP process opens new perspectives for macromolecular engineering in scCO2 without the utilization of fluorinated comonomers or organic solvents. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Human-Centric Teaming in a Multi-Agent EVA Assembly Task

    NASA Technical Reports Server (NTRS)

    Rehnmark, Fredrik; Currie, Nancy; Ambrose, Robert O.; Culbert, Christopher

    2004-01-01

    NASA's Human Space Flight program depends heavily on spacewalks performed by pairs of suited human astronauts. These Extra-Vehicular Activities (EVAs) are severely restricted in both duration and scope by consumables and available manpower.An expanded multi-agent EVA team combining the information-gathering and problem-solving skills of human astronauts with the survivability and physical capabilities of highly dexterous space robots is proposed. A 1-g test featuring two NASA/DARPA Robonaut systems working side-by-side with a suited human subject is conducted to evaluate human-robot teaming strategies in the context of a simulated EVA assembly task based on the STS-61B ACCESS flight experiment.

  10. Development of an Extra-vehicular (EVA) Infrared (IR) Camera Inspection System

    NASA Technical Reports Server (NTRS)

    Gazarik, Michael; Johnson, Dave; Kist, Ed; Novak, Frank; Antill, Charles; Haakenson, David; Howell, Patricia; Pandolf, John; Jenkins, Rusty; Yates, Rusty

    2006-01-01

    Designed to fulfill a critical inspection need for the Space Shuttle Program, the EVA IR Camera System can detect crack and subsurface defects in the Reinforced Carbon-Carbon (RCC) sections of the Space Shuttle s Thermal Protection System (TPS). The EVA IR Camera performs this detection by taking advantage of the natural thermal gradients induced in the RCC by solar flux and thermal emission from the Earth. This instrument is a compact, low-mass, low-power solution (1.2cm3, 1.5kg, 5.0W) for TPS inspection that exceeds existing requirements for feature detection. Taking advantage of ground-based IR thermography techniques, the EVA IR Camera System provides the Space Shuttle program with a solution that can be accommodated by the existing inspection system. The EVA IR Camera System augments the visible and laser inspection systems and finds cracks and subsurface damage that is not measurable by the other sensors, and thus fills a critical gap in the Space Shuttle s inspection needs. This paper discusses the on-orbit RCC inspection measurement concept and requirements, and then presents a detailed description of the EVA IR Camera System design.

  11. Advanced EVA Capabilities: A Study for NASA's Revolutionary Aerospace Systems Concept Program

    NASA Technical Reports Server (NTRS)

    Hoffman, Stephen J.

    2004-01-01

    This report documents the results of a study carried out as part of NASA s Revolutionary Aerospace Systems Concepts Program examining the future technology needs of extravehicular activities (EVAs). The intent of this study is to produce a comprehensive report that identifies various design concepts for human-related advanced EVA systems necessary to achieve the goals of supporting future space exploration and development customers in free space and on planetary surfaces for space missions in the post-2020 timeframe. The design concepts studied and evaluated are not limited to anthropomorphic space suits, but include a wide range of human-enhancing EVA technologies as well as consideration of coordination and integration with advanced robotics. The goal of the study effort is to establish a baseline technology "road map" that identifies and describes an investment and technical development strategy, including recommendations that will lead to future enhanced synergistic human/robot EVA operations. The eventual use of this study effort is to focus evolving performance capabilities of various EVA system elements toward the goal of providing high performance human operational capabilities for a multitude of future space applications and destinations. The data collected for this study indicate a rich and diverse history of systems that have been developed to perform a variety of EVA tasks, indicating what is possible. However, the data gathered for this study also indicate a paucity of new concepts and technologies for advanced EVA missions - at least any that researchers are willing to discuss in this type of forum.

  12. Rapid self-assembly of block copolymers to photonic crystals

    DOEpatents

    Xia, Yan; Sveinbjornsson, Benjamin R; Grubbs, Robert H; Weitekamp, Raymond; Miyake, Garret M; Atwater, Harry A; Piunova, Victoria; Daeffler, Christopher Scot; Hong, Sung Woo; Gu, Weiyin; Russell, Thomas P.

    2016-07-05

    The invention provides a class of copolymers having useful properties, including brush block copolymers, wedge-type block copolymers and hybrid wedge and polymer block copolymers. In an embodiment, for example, block copolymers of the invention incorporate chemically different blocks comprising polymer size chain groups and/or wedge groups that significantly inhibit chain entanglement, thereby enhancing molecular self-assembly processes for generating a range of supramolecular structures, such as periodic nanostructures and microstructures. The present invention also provides useful methods of making and using copolymers, including block copolymers.

  13. Underwater EVA training in the WETF with astronaut Robert L. Stewart

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Underwater extravehicular activity (EVA) training in the weightless environment training facility (WETF) with astronaut Robert L. Stewart. Stewart is simulating a planned EVA using the mobile foot restraint device and a one-G version of the Canadian-built remote manipulator system.

  14. Lignin poly(lactic acid) copolymers

    DOEpatents

    Olsson, Johan Vilhelm; Chung, Yi-Lin; Li, Russell Jingxian; Waymouth, Robert; Sattely, Elizabeth; Billington, Sarah; Frank, Curtis W.

    2017-02-14

    Provided herein are graft co-polymers of lignin and poly(lactic acid) (lignin-g-PLA copolymer), thermoset and thermoplastic polymers including them, methods of preparing these polymers, and articles of manufacture including such polymers.

  15. Influence of an Interfacial Effect on the Laser Performance of a Rhodamine 6G/Cellulose Acetate Waveguide on a Vinylidene Fluoride Copolymer Layer.

    PubMed

    Tsutsumi, Naoto; Hirano, Yoshinori; Kinashi, Kenji; Sakai, Wataru

    2018-06-12

    The fluorescent properties of dyes and fluorophores in condensed matter significantly affect the laser performance of organic dye lasers and fluorescent polymer lasers. Concentration quenching of fluorescence is commonly observed in condensed matter. Several approaches have been presented to suppress such quenching, such as the use of a dendrimer and the use of effective energy transfer in a guest-host system. The enhanced fluorescence of rhodamine 6G (R6G) dye on a vinylidene fluoride polymer is an alternative method for enhancing laser performance because of the roughness of the P(VDF-TrFE) surface and the interaction between polar β-crystals of P(VDF-TrFE) and R6G dye. In this paper, a significant improvement in slope efficiency (SE) is demonstrated without a significant depression in the lasing threshold for distributed feedback (DFB) and distributed Bragg reflector (DBR) lasers fabricated using an R6G-dispersed cellulose acetate (CA) matrix spin-coated onto a copolymer of vinylidene fluoride and trifluoroethylene P(VDF-TrFE) thin film. SEs of 3.4 and 1.3% were measured for DBR and DFB laser devices with CA/R6G on a P(VDF-TrFE) thin film, respectively, whereas an SE of less than 1.0% was measured for both corresponding laser devices without a P(VDF-TrFE) thin film. From the aspect of simple fabrication procedures, repeatability in device fabrication and performance, stability of the device, time for device fabrication, the present approach is the most preferable way for industrial applications, requiring only the additional step of spin-coating of a P(VDF-TrFE) thin film.

  16. Genomic characterization of two new enterovirus types, EV-A114 and EV-A121.

    PubMed

    Deshpande, Jagadish M; Sharma, Deepa K; Saxena, Vinay K; Shetty, Sushmitha A; Qureshi, Tarique Husain I H; Nalavade, Uma P

    2016-12-01

    Enteroviruses cause a variety of illnesses of the gastrointestinal tract, central nervous system and cardiovascular system. Phylogenetic analysis of VP1 sequences has identified 106 different human enteroviruses classified into four enterovirus species within the genus Enterovirus of the family Picornaviridae. It is likely that not all enterovirus types have been discovered. Between September 2013 and October 2014, stool samples of 6274 apparently healthy children of up to 5 years of age residing in Gorakhpur district, Uttar Pradesh, India were screened for enteroviruses. Virus isolates obtained in RD and Hep-2c cells were identified by complete VP1 sequencing. Enteroviruses were isolated from 3042 samples. A total of 87 different enterovirus types were identified. Two isolates with 71 and 74 % nucleotide sequence similarity to all other known enteroviruses were recognized as novel types. In this paper we report identification and complete genome sequence analysis of these two isolates classified as EV-A114 and EV-A121.

  17. The role of inserted polymers in polymeric insulation materials: insights from QM/MD simulations.

    PubMed

    Li, Chunyang; Zhao, Hong; Zhang, Hui; Wang, Ying; Wu, Zhijian; Han, Baozhong

    2018-02-28

    In this study, we performed a quantum chemical molecular dynamics (QM/MD) simulation to investigate the space charge accumulation process in copolymers of polyethylene (PE) with ethylene acrylic acid (EAA), ethylene vinyl acetate (EVA), styrene-ethylene-butadiene-styrene (SEBS), and black carbon (BC). We predicted that BC, especially branched BC, would possess the highest electron affinity and is identified as the most promising filler in power cable insulation. Following incorporations of 0-4 high-energy electrons into the composites, branched BC exhibited the highest stability and almost all electrons were trapped by it. Therefore, PE was protected efficiently and BC can be considered as an efficient filler for high voltage cables and an inhibitor of tree formation. On the contrary, although EAA, EVA, and SEBS can trap high-energy electrons, the latter can be supersaturated in composites of EAA, EVA, and SEBS with PE. The inserted polymers was unavoidably destroyed following C-H and C-O bond cleavage, which results from the interactions and charge transfer between PE and inserted polymers. The content effects of -COOH, benzene, and -OCOCH 3 groups on the electron trapping, mobility and stability of PE were also investigated systematically. We hope this knowledge gained from this work will be helpful in understanding the role of inserted polymers and the growth mechanisms of electrical treeing in high voltage cable insulation.

  18. Phase Behavior of Three PBX Elastomers in High-Pressure Chlorodifluoromethane

    NASA Astrophysics Data System (ADS)

    Lee, Byung-Chul

    2017-10-01

    The phase equilibrium behavior data are presented for three kinds of commercial polymer-bonded explosive (PBX) elastomers in chlorodifluoromethane (HCFC22). Levapren^{{registered }} ethylene- co-vinyl acetate (LP-EVA), HyTemp^{{registered }} alkyl acrylate copolymer (HT-ACM), and Viton^{{registered }} fluoroelastomer (VT-FE) were used as the PBX elastomers. For each elastomer + HCFC22 system, the cloud point (CP) and/or bubble point (BP) pressures were measured while varying the temperature and elastomer composition using a phase equilibrium apparatus fitted with a variable-volume view cell. The elastomers examined in this study indicated a lower critical solution temperature phase behavior in the HCFC22 solvent. LP-EVA showed the CPs at temperatures of 323 K to 343 K and at pressures of 3 MPa to 10 MPa, whereas HT-ACM showed the CPs at conditions between 338 K and 363 K and between 4 MPa and 12 MPa. For the LP-EVA and HT-ACM elastomers, the BP behavior was observed at temperatures below about 323 K. For the VT-FE + HCFC22 system, only the CP behavior was observed at temperatures between 323 K and 353 K and at pressures between 6 MPa and 21 MPa. As the elastomer composition increased, the CP pressure increased, reached a maximum value at a specific elastomer composition, and then remained almost constant.

  19. Shoulder Injuries in US Astronauts Related to EVA Suit Design

    NASA Technical Reports Server (NTRS)

    Scheuring, R. A.; McCulloch, P.; Van Baalen, Mary; Minard, Charles; Watson, Richard; Blatt, T.

    2011-01-01

    Introduction: For every one hour spent performing extravehicular activity (EVA) in space, astronauts in the US space program spend approximately six to ten hours training in the EVA spacesuit at NASA-Johnson Space Center's Neutral Buoyancy Lab (NBL). In 1997, NASA introduced the planar hard upper torso (HUT) EVA spacesuit which subsequently replaced the existing pivoted HUT. An extra joint in the pivoted shoulder allows increased mobility but also increased complexity. Over the next decade a number of astronauts developed shoulder problems requiring surgical intervention, many of whom performed EVA training in the NBL. This study investigated whether changing HUT designs led to shoulder injuries requiring surgical repair. Methods: US astronaut EVA training data and spacesuit design employed were analyzed from the NBL data. Shoulder surgery data was acquired from the medical record database, and causal mechanisms were obtained from personal interviews Analysis of the individual HUT designs was performed as it related to normal shoulder biomechanics. Results: To date, 23 US astronauts have required 25 shoulder surgeries. Approximately 48% (11/23) directly attributed their injury to training in the planar HUT, whereas none attributed their injury to training in the pivoted HUT. The planar HUT design limits shoulder abduction to 90 degrees compared to approximately 120 degrees in the pivoted HUT. The planar HUT also forces the shoulder into a forward flexed position requiring active retraction and extension to increase abduction beyond 90 degrees. Discussion: Multiple factors are associated with mechanisms leading to shoulder injury requiring surgical repair. Limitations to normal shoulder mechanics, suit fit, donning/doffing, body position, pre-existing injury, tool weight and configuration, age, in-suit activity, and HUT design have all been identified as potential sources of injury. Conclusion: Crewmembers with pre-existing or current shoulder injuries or certain

  20. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate...) The acrylate ester copolymer is a fully polymerized copolymer of ethyl acrylate, methyl methacrylate...

  1. EVA Radio DRATS 2011 Report

    NASA Technical Reports Server (NTRS)

    Swank, Aaron J.; Bakula, Casey J.

    2012-01-01

    In the Fall of 2011, National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) participated in the Desert Research and Technology Studies (DRATS) field experiments held near Flagstaff, Arizona. The objective of the DRATS outing is to provide analog mission testing of candidate technologies for space exploration, especially those technologies applicable to human exploration of extra- terrestrial rocky bodies. These activities are performed at locations with similarities to extra-terrestrial conditions. This report describes the Extravehicular Activity (EVA) Dual-Band Radio Communication System which was demonstrated during the 2011 outing. The EVA radio system is designed to transport both voice and telemetry data through a mobile ad hoc wireless network and employs a dual-band radio configuration. Some key characteristics of this system include: 1. Dual-band radio configuration. 2. Intelligent switching between two different capability wireless networks. 3. Self-healing network. 4. Simultaneous data and voice communication.

  2. Polyether-polyester graft copolymer

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L. (Inventor)

    1987-01-01

    Described is a polyether graft polymer having improved solvent resistance and crystalline thermally reversible crosslinks. The copolymer is prepared by a novel process of anionic copolymerization. These polymers exhibit good solvent resistance and are well suited for aircraft parts. Previous aromatic polyethers, also known as polyphenylene oxides, have certain deficiencies which detract from their usefulness. These commercial polymers are often soluble in common solvents including the halocarbon and aromatic hydrocarbon types of paint thinners and removers. This limitation prevents the use of these polyethers in structural articles requiring frequent painting. In addition, the most popular commercially available polyether is a very high melting plastic. This makes it considerably more difficult to fabricate finished parts from this material. These problems are solved by providing an aromatic polyether graft copolymer with improved solvent resistance and crystalline thermally reversible crosslinks. The graft copolymer is formed by converting the carboxyl groups of a carboxylated polyphenylene oxide polymer to ionic carbonyl groups in a suitable solvent, reacting pivalolactone with the dissolved polymer, and adding acid to the solution to produce the graft copolymer.

  3. Simulation of Martian EVA at the Mars Society Arctic Research Station

    NASA Astrophysics Data System (ADS)

    Pletser, V.; Zubrin, R.; Quinn, K.

    The Mars Society has established a Mars Arctic Research Station (M.A.R.S.) on Devon Island, North of Canada, in the middle of the Haughton crater formed by the impact of a large meteorite several million years ago. The site was selected for its similarities with the surface of the Mars planet. During the Summer 2001, the MARS Flashline Research Station supported an extended international simulation campaign of human Mars exploration operations. Six rotations of six person crews spent up to ten days each at the MARS Flashline Research Station. International crews, of mixed gender and professional qualifications, conducted various tasks as a Martian crew would do and performed scientific experiments in several fields (Geophysics, Biology, Psychology). One of the goals of this simulation campaign was to assess the operational and technical feasibility of sustaining a crew in an autonomous habitat, conducting a field scientific research program. Operations were conducted as they would be during a Martian mission, including Extra-Vehicular Activities (EVA) with specially designed unpressurized suits. The second rotation crew conducted seven simulated EVAs for a total of 17 hours, including motorized EVAs with All Terrain Vehicles, to perform field scientific experiments in Biology and Geophysics. Some EVAs were highly successful. For some others, several problems were encountered related to hardware technical failures and to bad weather conditions. The paper will present the experiment programme conducted at the Mars Flashline Research Station, the problems encountered and the lessons learned from an EVA operational point of view. Suggestions to improve foreseen Martian EVA operations will be discussed.

  4. The development and characterization of degradable poly(vinyl ester) and poly(vinyl ester)/PEO block copolymers

    NASA Astrophysics Data System (ADS)

    Lipscomb, Corinne Elizabeth

    The development of biodegradable materials is a challenging and important problem in polymer science. A review of the state of the art in degradable materials is presented, which reveals that current biodegradable materials do not exhibit the thermal or mechanical properties necessary for widespread applications. One strategy for toughening polymeric materials, which has previously been applied to non-degradable thermoplastics and thermoplastic elastomers, is the formation of block copolymers. Poly(vinyl esters) (PVE) homopolymers are known to have a wide range of properties, but PVE block copolymers comprise a class of inexpensive and (bio)degradable materials that were previously unknown. Therefore, the synthesis and properties of these block copolymers were explored in an effort to develop robust degradable materials. This thesis research probes the reaction conditions necessary for the reversible-addition fragmentation chain transfer (RAFT) polymerization and chain extension reactions of vinyl ester monomers. PVE di- and triblock copolymers are synthesized and studied, and the triblock copolymers display extremely poor toughness due to their relatively low molecular weights in light of the high entanglement molecular weight of the poly(vinyl acetate) center block. Attempts to improve the mechanical properties of these materials focus on the incorporation of poly(ethylene oxide) (PEO) as a low entanglement molecular weight and biocompatible center block in PVE-containing triblock copolymers. Depending on the choice of PVE endblocks and the overall polymer composition, crystallization of the PEO block can be controlled, confined, or inhibited. Polymers in which PEO crystallization is completely inhibited exhibit enhanced mechanical properties and behave as weak thermoplastics. In order to understand the relationship between the inhibition of PEO crystallization and the mechanical properties of PVE/PEO materials, these polymers were studied using dynamic

  5. Polyether/Polyester Graft Copolymers

    NASA Technical Reports Server (NTRS)

    Bell, Vernon L., Jr.; Wakelyn, N.; Stoakley, D. M.; Proctor, K. M.

    1986-01-01

    Higher solvent resistance achieved along with lower melting temperature. New technique provides method of preparing copolymers with polypivalolactone segments grafted onto poly (2,6-dimethyl-phenylene oxide) backbone. Process makes strong materials with improved solvent resistance and crystalline, thermally-reversible crosslinks. Resulting graft copolymers easier to fabricate into useful articles, including thin films, sheets, fibers, foams, laminates, and moldings.

  6. Single step synthesis and organization of gold colloids assisted by copolymer templates

    NASA Astrophysics Data System (ADS)

    Sarrazin, Aurélien; Gontier, Arthur; Plaud, Alexandre; Béal, Jérémie; Yockell-Lelièvre, Hélène; Bijeon, Jean-Louis; Plain, Jérôme; Adam, Pierre-Michel; Maurer, Thomas

    2014-06-01

    We report here an original single-step process for the synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared using polystyrene (PS)-polymethylmethacrylate copolymer and thiolated PS with propylene glycol methyl ether acetate as a solvent. The spin-coating and annealing of this solution then allows the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (Au NPs) per PS domain. For high concentrations of Au NPs in PS domains, the coupling between plasmonic NPs leads to the observation of a second peak in the optical extinction spectrum. Such a collective effect could be relevant for the development of optical strain sensors in the near future.

  7. The development of a test methodology for the evaluation of EVA gloves

    NASA Technical Reports Server (NTRS)

    O'Hara, John M.; Cleland, John; Winfield, Dan

    1988-01-01

    This paper describes the development of a standardized set of tests designed to assess EVA-gloved hand capabilities in six measurement domains: range of motion, strength, tactile perception, dexterity, fatigue, and comfort. Based upon an assessment of general human-hand functioning and EVA task requirements, several tests within each measurement domain were developed to provide a comprehensive evaluation. All tests were designed to be conducted in a glove box with the bare hand as a baseline and the EVA glove at operating pressure.

  8. Directed self assembly of block copolymers using chemical patterns with sidewall guiding lines, backfilled with random copolymer brushes.

    PubMed

    Pandav, Gunja; Durand, William J; Ellison, Christopher J; Willson, C Grant; Ganesan, Venkat

    2015-12-21

    Recently, alignment of block copolymer domains has been achieved using a topographically patterned substrate with a sidewall preferential to one of the blocks. This strategy has been suggested as an option to overcome the patterning resolution challenges facing chemoepitaxy strategies, which utilize chemical stripes with a width of about half the period of block copolymer to orient the equilibrium morphologies. In this work, single chain in mean field simulation methodology was used to study the self assembly of symmetric block copolymers on topographically patterned substrates with sidewall interactions. Random copolymer brushes grafted to the background region (space between patterns) were modeled explicitly. The effects of changes in pattern width, film thicknesses and strength of sidewall interaction on the resulting morphologies were examined and the conditions which led to perpendicular morphologies required for lithographic applications were identified. A number of density multiplication schemes were studied in order to gauge the efficiency with which the sidewall pattern can guide the self assembly of block copolymers. The results indicate that such a patterning technique can potentially utilize pattern widths of the order of one-two times the period of block copolymer and still be able to guide ordering of the block copolymer domains up to 8X density multiplication.

  9. Astronaut Ronald Evans is suited up for EVA training

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Astronaut Ronald E. Evans, command module pilot of the Apollo 17 lunar landing mission, is assisted by technicians in suiting up for extravehicular activity (EVA) training in a water tank in bldg 5 at the Manned Spacecraft Center (49970); Evans participates in EVA training in a water tank in bldg 5 at the Manned Spacecraft Center. The structure in the picture simulates the Scientific Instrument Module (SIM) bay of the Apollo 17 Service Module (49971).

  10. Gerst during EVA

    NASA Image and Video Library

    2014-10-07

    ISS041-E-067002 (7 Oct. 2014) --- NASA astronaut Reid Wiseman, Expedition 41 flight engineer, participates in a session of extravehicular activity (EVA) as work continues on the International Space Station. During the six-hour, 13-minute spacewalk, Wiseman and European Space Agency astronaut Alexander Gerst (out of frame), flight engineer, worked outside the space station's Quest airlock relocating a failed cooling pump to external stowage and installing gear that provides back up power to external robotics equipment.

  11. Wiseman during EVA

    NASA Image and Video Library

    2014-10-07

    ISS041-E-067002 (7 Oct. 2014) --- NASA astronaut Reid Wiseman, Expedition 41 flight engineer, participates in a session of extravehicular activity (EVA) as work continues on the International Space Station. During the six-hour, 13-minute spacewalk, Wiseman and European Space Agency astronaut Alexander Gerst (out of frame), flight engineer, worked outside the space station's Quest airlock relocating a failed cooling pump to external stowage and installing gear that provides back up power to external robotics equipment.

  12. Russian EVA 34

    NASA Image and Video Library

    2013-08-16

    ISS036-E-033400 (16 Aug. 2013) --- Russian cosmonaut Alexander Misurkin (lower left), Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the seven-hour, 29-minute spacewalk ? the longest ever conducted by a pair of Russian cosmonauts ? Misurkin and Fyodor Yurchikhin (out of frame) rigged cables for the future arrival of a Russian laboratory module and installed an experiment panel.

  13. Russian EVA 34

    NASA Image and Video Library

    2013-08-16

    ISS036-E-033402 (16 Aug. 2013) --- Russian cosmonaut Alexander Misurkin (lower left), Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the seven-hour, 29-minute spacewalk ? the longest ever conducted by a pair of Russian cosmonauts ? Misurkin and Fyodor Yurchikhin (out of frame) rigged cables for the future arrival of a Russian laboratory module and installed an experiment panel.

  14. A primer on EVA for health care providers.

    PubMed

    Grant, James L

    2007-01-01

    Unlike accounting earnings, economic profit (EVA) is a measure of a company's true earnings because it fully "accounts" for the costs of all forms of financing, including debt and equity. In the EVA view, a company is not truly profitable unless it earns a return on capital that bests the opportunity cost of capital. That being said, the question addressed here is how to measure the economic profit of providers in the health care sector, which is largely comprised of not-for-profit organizations such as clinics, laboratories, and hospitals.

  15. Asteroid Redirect Crewed Mission Space Suit and EVA System Maturation

    NASA Technical Reports Server (NTRS)

    Bowie, Jonathan T.; Kelly, Cody; Buffington, Jesse; Watson, Richard D.

    2015-01-01

    The Asteroid Redirect Crewed Mission (ARCM) requires a Launch/Entry/Abort (LEA) suit capability and short duration Extra Vehicular Activity (EVA) capability from the Orion spacecraft. For this mission, the pressure garment that was selected, for both functions, is the Modified Advanced Crew Escape Suit (MACES) with EVA enhancements and the life support option that was selected is the Exploration Portable Life Support System (PLSS). The proposed architecture was found to meet the mission constraints, but much more work is required to determine the details of the required suit upgrades, the integration with the PLSS, and the rest of the tools and equipment required to accomplish the mission. This work has continued over the last year to better define the operations and hardware maturation of these systems. EVA simulations have been completed in the NBL and interfacing options have been prototyped and analyzed with testing planned for late 2014. For NBL EVA simulations, in 2013, components were procured to allow in-house build up for four new suits with mobility enhancements built into the arms. Boots outfitted with clips that fit into foot restraints have also been added to the suit and analyzed for possible loads. Major suit objectives accomplished this year in testing include: evaluation of mobility enhancements, ingress/egress of foot restraint, use of foot restraint for worksite stability, ingress/egress of Orion hatch with PLSS mockup, and testing with two crew members in the water at one time to evaluate the crew's ability to help one another. Major tool objectives accomplished this year include using various other methods for worksite stability, testing new methods for asteroid geologic sampling and improving the fidelity of the mockups and crew equipment. These tests were completed on a medium fidelity capsule mockup, asteroid vehicle mockup, and asteroid mockups that were more accurate for an asteroid type EVA than previous tests. Another focus was the

  16. Extravehicular activities limitations study. Volume 2: Establishment of physiological and performance criteria for EVA gloves

    NASA Technical Reports Server (NTRS)

    Ohara, John M.; Briganti, Michael; Cleland, John; Winfield, Dan

    1988-01-01

    One of the major probelms faced in Extravehicular Activity (EVA) glove development has been the absence of concise and reliable methods to measure the effects of EVA gloves on human hand capabilities. This report describes the development of a standardized set of tests designed to assess EVA-gloved hand capabilities in six measurement domains: Range of Motion, Strength, Tactile Perception, Dexterity, Fatigue, and Comfort. Based on an assessment of general human hand functioning and EVA task requirements several tests within each measurement domain were developed to provide a comprehensive evaluation. All tests were designed to be conducted in a glove box with the bare hand as a baseline and the EVA glove at operating pressure. A test program was conducted to evaluate the tests using a representative EVA glove. Eleven test subjects participated in a repeated-measures design. The report presents the results of the tests in each capability domain.

  17. Microwave irradiation induced modifications on the interfaces in SAN/EVA/PVC and PVAc/BPA/PVP ternary polymer blends: Positron lifetime study

    NASA Astrophysics Data System (ADS)

    Dinesh, Meghala; Chikkakuntappa, Ranganathaiah

    2013-09-01

    Ternary polymer blends of poly(styrene-co-acrylonitrile)/poly(ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and poly(vinyl acetate)/bisphenol A/polyvinylpyrrolidone (PVAc/BPA/PVP) with different compositions have been prepared by solvent casting method and characterized by positron lifetime spectroscopy and differential scanning calorimetry DSC. Phase modifications have been induced by irradiating the blends with microwave radiation. These changes have been monitored by measuring the free-volume content in the blends. The results clearly show improved interactions between the constituent polymers of the blends upon microwave irradiation. However, the free-volume data and DSC measurements are found to be inadequate to reveal the changes at the interfaces and the interfaces determine the final properties of the blend. For this we have used hydrodynamic interaction (αij) approach developed by us to measure strength of hydrodynamic interaction at the interfaces. These results show that microwave irradiation stabilizes the interfaces if the blend contains strong polar groups. SAN/EVA/PVC blend shows an increased effective hydrodynamic interaction from -3.18 to -4.85 at composition 50/35/15 upon microwave irradiation and PVAc/BPA/PVP blend shows an increased effective hydrodynamic interaction from -3.81 to -7.57 at composition 20/50/30 after irradiation.

  18. Astronaut Dale Gardner holds up for sale sign after EVA

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Dale A. Gardner, having just completed the major portion of his second extravehicular activity (EVA) period in three days, holds up a 'for sale' sign. Astronaut Joseph P. ALlen IV, who also participated in the two EVA's, is reflected in Gardner's helmet visor. A portion of each of two recovered satellites is in the lower right corner, with Westar nearer Discovery's aft.

  19. Method of forming oriented block copolymer line patterns, block copolymer line patterns formed thereby, and their use to form patterned articles

    DOEpatents

    Russell, Thomas P.; Hong, Sung Woo; Lee, Doug Hyun; Park, Soojin; Xu, Ting

    2015-10-13

    A block copolymer film having a line pattern with a high degree of long-range order is formed by a method that includes forming a block copolymer film on a substrate surface with parallel facets, and annealing the block copolymer film to form an annealed block copolymer film having linear microdomains parallel to the substrate surface and orthogonal to the parallel facets of the substrate. The line-patterned block copolymer films are useful for the fabrication of magnetic storage media, polarizing devices, and arrays of nanowires.

  20. Method of forming oriented block copolymer line patterns, block copolymer line patterns formed thereby, and their use to form patterned articles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Russell, Thomas P.; Hong, Sung Woo; Lee, Dong Hyun

    A block copolymer film having a line pattern with a high degree of long-range order is formed by a method that includes forming a block copolymer film on a substrate surface with parallel facets, and annealing the block copolymer film to form an annealed block copolymer film having linear microdomains parallel to the substrate surface and orthogonal to the parallel facets of the substrate. The line-patterned block copolymer films are useful for the fabrication of magnetic storage media, polarizing devices, and arrays of nanowires.

  1. Utilization of ISS to Develop and Test Operational Concepts and Hardware for Low-Gravity Terrestrial EVA

    NASA Technical Reports Server (NTRS)

    Gast, Matthew A.

    2010-01-01

    NASA has considerable experience in two areas of Extravehicular Activities (EVA). The first can be defined as microgravity, orbital EVAs. This consists of everything done in low Earth orbit (LEO), from the early, proof of concept EVAs conducted during the Gemini program of the 1960s, to the complex International Space Station (ISS) assembly tasks of the first decade of the 21st century. The second area of expertise is comprised of those EVAs conducted on the lunar surface, under a gravitational force one-sixth that of Earth. This EVA expertise encapsulates two extremes - microgravity and Earthlike gravitation - but is insufficient as humans expand their exploration purview, most notably with respect to spacewalks conducted on very low-gravity bodies, such as near- Earth objects (NEO) and the moons of Mars. The operational and technical challenges of this category of EVA have yet to be significantly examined, and as such, only a small number of operational concepts have been proposed thus far. To ensure mission success, however, EVA techniques must be developed and vetted to allow the selection of operational concepts that can be utilized across an assortment of destinations whose physical characteristics vary. This paper examines the utilization of ISS-based EVAs to test operational concepts and hardware in preparation for a low-gravity terrestrial EVA. While the ISS cannot mimic some of the fundamental challenges of a low-gravity terrestrial EVA - such as rotation rate and surface composition - it may be the most effective test bed available.

  2. Health and Safety Benefits of Small Pressurized Suitport Rovers as EVA Surface Support Vehicles

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael L.; Abercromby, Andrew F. J.

    2008-01-01

    Pressurized safe-haven providing SPE protection and decompression sickness (DCS) treatment capabilities within 20 mins at all times. Up to 50% reduction in time spent in EVA suits (vs. Unpressurized Rovers) for equal or greater Boots-on-Surface EVA exploration time. Reduces suit-induced trauma and provides improved options for nutrition, hydration, and waste-management. Time spent inside SPR during long translations may be spent performing resistive and cardiovascular exercise. Multiple shorter EVAs versus single 8 hr EVAs increases DCS safety and decreases prebreathe requirements. SPRs also offer many potential operational, engineering and exploration benefits not addressed here.

  3. Enhanced Adhesion of EVA Laminates to Primed Glass Substrates Subjected to Damp-Heat Exposure

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Pern, F. J.; Jorgensen, G. J.

    2005-02-01

    We investigated the effectiveness of glass-surface priming to promote enhanced adhesion of EVA laminates during damp-heat exposure at 85 C and 85% relative humidity. The primary objective was to develop advanced encapsulant formulations by incorporation of various primer formulations that exhibit improved adhesion during damp-heat exposure. Several primer formulations were identified that greatly enhanced the EVA adhesion strength, including to the extent that peeling could not be initiated, even for the laminates of the glass substrate/fast-cure EVA15295P/TPE backsheet (a Tedlar/polyester/EVA tri-laminate) that were exposed in a damp-heat test chamber for more than 750 h. The results show that a synergisticmore » increase in the interfacial hydrophobicity, siloxane density, and cross-linking density are the key attributes to the improvement in the EVA adhesion strength.« less

  4. Information requirements and methodology for development of an EVA crewmember's heads up display

    NASA Astrophysics Data System (ADS)

    Petrek, J. S.

    This paper presents a systematic approach for developing a Heads Up Display (HUD) to be used within the helmet of the Extra Vehicular Activity (EVA) crewmember. The information displayed on the EVA HUD will be analogous to EVA Flight Data File (FDF) information, which is an integral part of NASA's current Space Transportation System. Another objective is to determine information requirements and media techniques ultimately leading to the helmet-mounted HUD presentation technique.

  5. CREW TRAINING (EXTRAVEHICULAR ACTIVITY [EVA]) - STS-41G - JSC

    NASA Image and Video Library

    1984-07-06

    S84-36956 (1 July 1984) --- Astronaut Robert L. Crippen, 41-G crew commander, prepares his SCUBA mask prior to submerging into the weightless environment training facility's 25 ft. deep pool to observe a simulation exercise for two fellow 41-G crewmembers assigned to an extravehicular activity (EVA) in space. Not pictured are Astronauts Kathryn D. Sullivan and David C. Leestma, mission specialists who will perform the EVA during the eight-day mission scheduled for October of this year.

  6. Biodegradable copolymers carrying cell-adhesion peptide sequences.

    PubMed

    Proks, Vladimír; Machová, Lud'ka; Popelka, Stepán; Rypácek, Frantisek

    2003-01-01

    Amphiphilic block copolymers are used to create bioactive surfaces on biodegradable polymer scaffolds for tissue engineering. Cell-selective biomaterials can be prepared using copolymers containing peptide sequences derived from extracellular-matrix proteins (ECM). Here we discuss alternative ways for preparation of amphiphilic block copolymers composed of hydrophobic polylactide (PLA) and hydrophilic poly(ethylene oxide) (PEO) blocks with cell-adhesion peptide sequences. Copolymers PLA-b-PEO were prepared by a living polymerisation of lactide in dioxane with tin(II)2-ethylhexanoate as a catalyst. The following approaches for incorporation of peptides into copolymers were elaborated. (a) First, a side-chain protected Gly-Arg-Gly-Asp-Ser-Gly (GRGDSG) peptide was prepared by solid-phase peptide synthesis (SPPS) and then coupled with delta-hydroxy-Z-amino-PEO in solution. In the second step, the PLA block was grafted to it via a controlled polymerisation of lactide initiated by the hydroxy end-groups of PEO in the side-chain-protected GRGDSG-PEO. Deprotection of the peptide yielded a GRGDSG-b-PEO-b-PLA copolymer, with the peptide attached through its C-end. (b) A protected GRGDSG peptide was built up on a polymer resin and coupled with Z-carboxy-PEO using a solid-phase approach. After cleavage of the delta-hydroxy-PEO-GRGDSG copolymer from the resin, polymerisation of lactide followed by deprotection of the peptide yielded a PLA-b-PEO-b-GRGDSG block copolymer, in which the peptide is linked through its N-terminus.

  7. Oxidative stress-mediated hemolytic activity of solvent exchange-prepared fullerene (C60) nanoparticles

    NASA Astrophysics Data System (ADS)

    Trpkovic, Andreja; Todorovic-Markovic, Biljana; Kleut, Duska; Misirkic, Maja; Janjetovic, Kristina; Vucicevic, Ljubica; Pantovic, Aleksandar; Jovanovic, Svetlana; Dramicanin, Miroslav; Markovic, Zoran; Trajkovic, Vladimir

    2010-09-01

    The present study investigated the hemolytic properties of fullerene (C60) nanoparticles prepared by solvent exchange using tetrahydrofuran (nC60THF), or by mechanochemically assisted complexation with macrocyclic oligosaccharide gamma-cyclodextrin (nC60CDX) or the copolymer ethylene vinyl acetate-ethylene vinyl versatate (nC60EVA-EVV). The spectrophotometrical analysis of hemoglobin release revealed that only nC60THF, but not nC60CDX or nC60EVA-EVV, was able to cause lysis of human erythrocytes in a dose- and time-dependent manner. Atomic force microscopy revealed that nC60THF-mediated hemolysis was preceded by erythrocyte shrinkage and increase in cell surface roughness. A flow cytometric analysis confirmed a decrease in erythrocyte size and demonstrated a significant increase in reactive oxygen species production in red blood cells exposed to nC60THF. The nC60THF-triggered hemolytic activity was efficiently reduced by the antioxidants N-acetylcysteine and butylated hydroxyanisole, as well as by serum albumin, the most abundant protein in human blood plasma. These data indicate that nC60THF can cause serum albumin-preventable hemolysis through oxidative stress-mediated damage of the erythrocyte membrane.

  8. Effect of polymer blend types and gamma radiation on the physico-chemical properties of polycarbonate

    NASA Astrophysics Data System (ADS)

    Nouh, S. A.; Magida, M. M.; Al-Shekify, L. S.; Bashter, I. I.

    2016-12-01

    Samples from polycarbonate (PC) were classified into two main groups. The first group was blended with Abietic acid (Rosin) with different compositions, while the second group was blended with ethylene-vinyl acetate (EVA) copolymer with almost the same composition. A comparative study of the effect of both Rosin and EVA concentration on the thermal stability of PC has been investigated using thermogravimetric analysis. The results show that blending with Rosin causes the dominance of degradation. Samples from PC with 20% Rosin blend were irradiated with gamma at the dose of range 20-300 kGy. The resultant effect of gamma radiation on the structural properties of the 20% Rosin/ 80%PC blend has been investigated using Fourier Transform Infrared FTIR spectroscopy. The results indicate that degradation of the polymer blend dominates, thus increases the creation of hot free radicals that leads to the formation of color centers in PC. In addition, the transmission of the 20% Rosin/80%PC samples as well as color changes was studied. The color intensity ΔE was greatly increased with increasing the gamma dose up to 300 kGy, accompanied by a significant increase in the blue color component.

  9. Next Generation Life Support: High Performance EVA Glove

    NASA Technical Reports Server (NTRS)

    Walsh, Sarah K.

    2015-01-01

    The objectives of the High Performance EVA Glove task are to develop advanced EVA gloves for future human space exploration missions and generate corresponding standards by which progress may be quantitatively assessed. New technologies and manufacturing techniques will be incorporated into the new gloves to address finger and hand mobility, injury reduction and durability in nonpristine environments. Three prototypes will be developed, each focusing on different technological advances. A robotic assist glove will integrate a powered grasping system into the current EVA glove design to reduce astronaut hand fatigue and hand injuries. A mechanical counter pressure (MCP) glove will be developed to further explore the potential of MCP technology and assess its capability for countering the effects of vacuum or low pressure environments on the body by using compression fabrics or materials to apply the necessary pressure. A gas pressurized glove, incorporating new technologies, will be the most flight-like of the three prototypes. Advancements include the development and integration of aerogel insulation, damage sensing components, dust-repellant coatings, and dust tolerant bearings.

  10. EVA Skills training in the NBL

    NASA Image and Video Library

    2012-11-27

    ESA astronaut and first astronaut from the United Kingdom, Timothy Peake, with NASA astronaut Scott Tingle (unassigned) during EVA Skills training in the NBL. Photo Date: November 27, 2012. Location: NBL - Pool Topside. Photographer: Robert Markowitz

  11. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035204 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  12. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035130 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  13. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035129 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  14. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035124 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  15. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035133 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  16. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035205 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  17. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035126 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  18. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035163 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers.

  19. Russian EVA 28

    NASA Image and Video Library

    2011-02-16

    ISS026-E-027391 (16 Feb. 2011) --- Russian cosmonaut Dmitry Kondratyev, Expedition 26 flight engineer, wearing a Russian Orlan-MK spacesuit, participates in a session of extravehicular activity (EVA) focused on the installation of two scientific experiments outside the Zvezda Service Module of the International Space Station. During the four-hour, 51-minute spacewalk, Kondratyev and Russian cosmonaut Oleg Skripochka (out of frame), flight engineer, installed a pair of earthquake and lightning sensing experiments and retrieved a pair of spacecraft material evaluation panels.

  20. EVA Suits Arrival

    NASA Image and Video Library

    2002-01-01

    Extravehicular Activity (EVA) suits packed inside containers arrive at the Space Station Processing Facility from Johnson Space Center in Texas. The suits will be used by STS-117 crew members to perform several spacewalks during the mission. The mission payload aboard Space Shuttle Atlantis is the S3/S4 integrated truss structure, along with a third set of solar arrays and batteries. The crew of six astronauts will install the truss to continue assembly of the International Space Station.

  1. EVA assembly of large space structure element

    NASA Technical Reports Server (NTRS)

    Bement, L. J.; Bush, H. G.; Heard, W. L., Jr.; Stokes, J. W., Jr.

    1981-01-01

    The results of a test program to assess the potential of manned extravehicular activity (EVA) assembly of erectable space trusses are described. Seventeen tests were conducted in which six "space-weight" columns were assembled into a regular tetrahedral cell by a team of two "space"-suited test subjects. This cell represents the fundamental "element" of a tetrahedral truss structure. The tests were conducted under simulated zero-gravity conditions. Both manual and simulated remote manipulator system modes were evaluated. Articulation limits of the pressure suit and zero gravity could be accommodated by work stations with foot restraints. The results of this study have confirmed that astronaut EVA assembly of large, erectable space structures is well within man's capabilities.

  2. The Effect of Nano Loading and Ultrasonic Compounding of EVA/LDPE/Nano-magnesium Hydroxide on Mechanical Properties and Distribution of Nano Particles

    NASA Astrophysics Data System (ADS)

    Azman, I. A.; Salleh, R. M.; Alauddin, S. M.; Shueb, M. I.

    2018-05-01

    Blends of Ethylene Vinyl Acetate (EVA) and Low-Density Polyethylene (LDPE) are promising composite which have good mechanical properties to environmental stress cracking. However, they lack fire resistant properties, which limits it usage in wire and cable industry. In order to improve flame retardancy ability, a range of nano-magnesium hydroxide (nano-MH) loading which is from 0 phr to maximum of 20 phr with ultrasonic extrusion 0-100 kHz frequencies have been introduced. Ultrasonic extrusion was used to improve the distribution of nano-MH. It was found that, 10 phr of nano loading with 100 kHz ultrasonic assisted has greater tensile strength compared to the nanocomposite without ultrasonication. Further increase of nano MH loading, will decrease the tensile properties. Better elongation at break was observed at10 phr nano-MH with the frequency of 50 kHz. The sample of 20 phr of nanoMH assisted with 50 kHz ultrasonic exhibits good flexural properties while 10 phr of nano-MH without the ultrasonic assisted demonstrates good in izod impact properties. From the evaluation of mechanical properties studied, it was found that 10 phr of nano-MH has shown the best performance among all the samples tested for EVA/LDPE/nano-MH composites. Transmission Electron Microscopy (TEM) has been conducted on 10 phr sample with different frequencies in order to observe the distribution of nano-MH particles. The sample with 100 kHz frequency shows more uniform dispersion of nano-MH in EVA/LDPE composites. This investigation indicates that the ultrasonic technology can enhance the mechanical properties studied as well as the dispersion of nano particles in the composite.

  3. Robinson during EVA 3

    NASA Image and Video Library

    2005-06-29

    S114-E-6221 (3 August 2005) --- Astronaut Stephen K. Robinson, STS-114 mission specialist, on the end of the station’s Canadarm2 (out of frame), slowly and cautiously makes his way to the underside of Space Shuttle Discovery to remove gap fillers from between the orbiter’s heat-shielding tiles during the mission’s third session of extravehicular activity (EVA).

  4. Robinson during EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6215 (3 August 2005) --- Astronaut Stephen K. Robinson, STS-114 mission specialist, on the end of the station’s Canadarm2 (out of frame), slowly and cautiously makes his way to the underside of Space Shuttle Discovery to remove gap fillers from between the orbiter’s heat-shielding tiles during the mission’s third of three sessions of extravehicular activity (EVA).

  5. Evaluation of an Anthropometric Human Body Model for Simulated EVA Task Assessment

    NASA Technical Reports Server (NTRS)

    Etter, Brad

    1996-01-01

    One of the more mission-critical tasks performed in space is extravehicular activity (EVA) which requires the astronaut to be external to the station or spacecraft, and subsequently at risk from the many threats posed by space. These threats include, but are not limited to: no significant atmosphere, harmful electromagnetic radiation, micrometeoroids, and space debris. To protect the astronaut from this environment, a special EVA suit is worn which is designed to maintain a sustainable atmosphere (at 1/3 atmosphere) and provide protection against the hazards of space. While the EVA suit serves these functions well, it does impose limitations on the astronaut as a consequence of the safety it provides. Since the astronaut is in a virtual vacuum, any atmospheric pressure inside the suit serves to pressurize the suit and restricts mobility of flexible joints (such as fabric). Although some of the EVA suit joints are fixed, rotary-style joints, most of the mobility is achieved by the simple flexibility of the fabric. There are multiple layers of fabric, each of which serves a special purpose in the safety of the astronaut. These multiple layers add to the restriction of motion the astronaut experiences in the space environment. Ground-based testing is implemented to evaluate the capability of EVA-suited astronauts to perform the various tasks in space. In addition to the restriction of motion imposed by the EVA suit, most EVA activity is performed in a micro-gravity (weight less) environment. To simulate weightlessness EVA-suited testing is performed in a neutral buoyancy simulator (NBS). The NBS is composed of a large container of water (pool) in which a weightless environment can be simulated. A subject is normally buoyant in the pressurized suit; however he/she can be made neutrally buoyant with the addition of weights. In addition, most objects the astronaut must interface with in the NBS sink in water and flotation must be added to render them "weightless". The

  6. Astronaut Story Musgrave during STS-6 EVA

    NASA Image and Video Library

    1983-04-07

    STS006-45-124 (7 April 1983) --- Astronaut F. Story Musgrave, STS-6 mission specialist, translates down the Earth-orbiting space shuttle Challenger’s payload bay door hinge line with a bag of latch tools. This photograph is among the first five still frames that recorded the April 7 extravehicular activity (EVA) of Dr. Musgrave and Donald H. Peterson, the flight’s other mission specialist. It was photographed with a handheld 70mm camera from inside the cabin by one of two crew members who remained on the flight deck during the EVA. Dr. Musgrave’s task here was to evaluate the techniques required to move along the payload bay’s edge with tools. In the lower left foreground are three canisters containing three getaway special (GAS) experiments. Part of the starboard wind and orbital maneuvering system (OMS) pod are seen back dropped against the blackness of space. The gold-foil protected object partially out of frame on the right is the airborne support equipment for the now vacated inertial upper stage (IUS) which aided the deployment of the tracking and data relay satellite on the flight’s first day. Astronauts Paul J. Weitz, command and Karol J. Bobko, pilot, remained inside the Challenger during the EVA. Photo credit: NASA

  7. The Education of Eva Hoffman.

    ERIC Educational Resources Information Center

    Proefriedt, William

    1991-01-01

    Reviews the autobiography of Eva Hoffman, "Lost in Translation: A Life in a New Language" (Dutton, 1989). Hoffman, whose family left Poland in the 1950s, offers a consciously bicultural view of the immigrant experience, in contrast to many autobiographies of those who forsake the old world for the new. (DM)

  8. Astronaut Ronald Evans photographed during transearth coast EVA

    NASA Image and Video Library

    1972-12-17

    AS17-152-23391 (17 Dec. 1972) --- Astronaut Ronald E. Evans is photographed performing extravehicular activity during the Apollo 17 spacecraft's trans-Earth coast. During his EVA, Evans, command module pilot, retrieved film cassettes from the lunar sounder, mapping camera and panoramic camera. The cylindrical object at Evans' left side is the mapping camera cassette. The total time for the trans-Earth EVA was one hour, seven minutes, 18 seconds, starting at ground elapsed time of 257:25 (2:28 p.m.) and ending at G.E.T. of 258:42 (3:35 p.m.) on Sunday, Dec. 17, 1972.

  9. Astronaut Ronald Evans photographed during transearth coast EVA

    NASA Image and Video Library

    1972-12-17

    AS17-152-23393 (17 Dec. 1972) --- Astronaut Ronald E. Evans is photographed performing extravehicular activity during the Apollo 17 spacecraft's trans-Earth coast. During his EVA, command module pilot Evans retrieved film cassettes from the Lunar Sounder, Mapping Camera, and Panoramic Camera. The cylindrical object at Evans' left side is the Mapping Camera cassette. The total time for the trans-Earth EVA was one hour seven minutes 18 seconds, starting at ground elapsed time of 257:25 (2:28 p.m.) and ending at ground elapsed timed of 258:42 (3:35 p.m.) on Sunday, Dec. 17, 1972.

  10. Helms holds onto the Rigid Umbilical during EVA

    NASA Image and Video Library

    2001-03-11

    STS102-314-003 (11 March 2001) --- Astronaut Susan J. Helms works while holding onto a rigid umbilical and with her feet anchored to the remote manipulator system (RMS) robot arm on the Space Shuttle Discovery. This extravehicular activity (EVA), on which Helms was joined by astronaut James S. Voss (out of frame), was the first of two scheduled STS-102 space walks. The pair, destined to become members of the Expedition Two crew aboard the station later in the mission, rode aboard Discovery into orbit and at the time of this EVA were still regarded as STS-102 mission specialists.

  11. EVA 4

    NASA Image and Video Library

    2006-12-18

    ISS014-E-10089 (18 Dec. 2006) --- European Space Agency (ESA) astronaut Christer Fuglesang, STS-116 mission specialist, uses a digital still camera to expose a photo of his helmet visor during the mission's fourth session of extravehicular activity (EVA) while Space Shuttle Discovery was docked with the International Space Station. Also visible in the reflections in the visor is astronaut Robert L. Curbeam Jr., mission specialist, as he works with the port overhead solar array wing on the station's P6 truss. The spacewalkers worked in tandem, using specially prepared, tape-insulated tools, to guide the array wing neatly inside its blanket box during the 6-hour, 38-minute spacewalk.

  12. Imide/arylene ether block copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, B. J.; Hergenrother, P. M.; Bass, R. G.

    1991-01-01

    Two series of imide/arylene either block copolymers were prepared using an arylene ether block and either an amorphous or semi-crystalline imide block. The resulting copolymers were characterized and selected physical and mechanical properties were determined. These results, as well as comparisons to the homopolymer properties, are discussed.

  13. Overview of EVA PRA for TPS Repair for Hubble Space Telescope Servicing Mission

    NASA Technical Reports Server (NTRS)

    Bigler, Mark; Duncan, Gary; Roeschel, Eduardo; Canga, Michael

    2010-01-01

    Following the Columbia accident in 2003, NASA developed techniques to repair the Thermal Protection System (TPS) in the event of damage to the TPS as one of several actions to reduce the risk to future flights from ascent debris, micro-meteoroid and/or orbital debris (MMOD). Other actions to help reduce the risk include improved inspection techniques, reduced shedding of debris from the External Tank and ability to rescue the crew with a launch on need vehicle. For the Hubble Space Telescope (HST) Servicing Mission the crew rescue capability was limited by the inability to safe haven on the International Space Station (ISS), resulting in a greater reliance on the repair capability. Therefore it was desirable to have an idea of the risk associated with conducting a repair, where the repair would have to be conducted using an Extra-Vehicular Activity (EVA). Previously, focused analyses had been conducted to quantify the risk associated with certain aspects of an EVA, for example the EVA Mobility Unit (EMU) or Space Suit; however, the analyses were somewhat limited in scope. A complete integrated model of an EVA which could quantify the risk associated with all of the major components of an EVA had never been done before. It was desired to have a complete integrated model to be able to assess the risks associated with an EVA to support the Space Shuttle Program (SSP) in making risk informed decisions. In the case of the HST Servicing Mission, this model was developed to assess specifically the risks associated with performing a TPS repair EVA. This paper provides an overview of the model that was developed to support the HST mission in the event of TPS damage. The HST Servicing Mission was successfully completed on May 24th 2009 with no critical TPS damage; therefore the model was not required for real-time mission support. However, it laid the foundation upon which future EVA quantitative risk assessments could be based.

  14. STS-103 crewmembers during NBL EVA training

    NASA Image and Video Library

    1999-06-21

    S99-06194 (21 June 1999) --- Astronaut C. Michael Foale, mission specialist, rehearses Extravehicular Activity (EVA) with the Hubble Space Telescope (HST) mockup in the Neutral Buoyancy Laboratory (NBL).

  15. Photos taken inside ISS during EVA day

    NASA Image and Video Library

    2013-07-09

    Astronaut Karen Nyberg,Expedition 36 flight engineer,is photographed at the Space Station Remote Manipulator System (SSRMS) controls in the U.S. Laboratory during a session of extravehicular activity (EVA).

  16. Thermo-Active Behavior of Ethylene-Vinyl Acetate | Multiwall Carbon Nanotube Composites Examined by in Situ near-Edge X-ray Absorption Fine-Structure Spectroscopy

    PubMed Central

    2015-01-01

    NEXAFS spectroscopy was used to investigate the temperature dependence of thermally active ethylene-vinyl acetate | multiwall carbon nanotube (EVA|MWCNT) films. The data shows systematic variations of intensities with increasing temperature. Molecular orbital assignment of interplaying intensities identified the 1s → π*C=C and 1s → π*C=O transitions as the main actors during temperature variation. Furthermore, enhanced near-edge interplay was observed in prestrained composites. Because macroscopic observations confirmed enhanced thermal-mechanical actuation in prestrained composites, our findings suggest that the interplay of C=C and C=O π orbitals may be instrumental to actuation. PMID:24803975

  17. Emergency vehicle alert system (EVAS)

    NASA Technical Reports Server (NTRS)

    Reed, Bill; Crump, Roger; Harper, Warren; Myneni, Krishna

    1995-01-01

    The Emergency Vehicle Alert System (EVAS) program is sponsored by the NASA/MSFC Technology Utilization (TU) office. The program was conceived to support the needs of hearing impaired drivers. The objective of the program is to develop a low-cost, small device which can be located in a personal vehicle and warn the driver, via a visual means, of the approach of an emergency vehicle. Many different technologies might be developed for this purpose and each has its own advantages and drawbacks. The requirements for an acoustic detection system, appear to be pretty stringent and may not allow the development of a reliable, low-cost device in the near future. The problems include variations in the sirens between various types of emergency vehicles, distortions due to wind and surrounding objects, competing background noise, sophisticated signal processing requirements, and omni-directional coverage requirements. Another approach is to use a Radio Frequency (RF) signal between the Emergency Vehicle (EV) and the Personal Vehicle (PV). This approach requires a transmitter on each EV and a receiver in each PV, however it is virtually assured that a system can be developed which works. With this approach, the real technology issue is how to make a system work as inexpensively as possible. This report gives a brief summary of the EVAS program from its inception and concentrates on describing the activities that occurred during Phase 4. References 1-3 describe activities under Phases 1-3. In the fourth phase of the program, the major effort to be expended was in development of the microcontroller system for the PV, refinement of some system elements and packaging for demonstration purposes. An EVAS system was developed and demonstrated which used standard spread spectrum modems with minor modifications.

  18. High Performance EVA Glove Collaboration: Glove Injury Data Mining Effort

    NASA Technical Reports Server (NTRS)

    Reid, C. R.; Benson, E.; England, S.; Charvat, J.; Norcross, J. R.; McFarland, S. M.; Rajulu, S.

    2015-01-01

    Human hands play a significant role during Extravehicular Activity (EVA) missions and Neutral Buoyancy Lab (NBL) training events, as they are needed for translating and performing tasks in the weightless environment. Because of this high frequency usage, hand and arm related injuries are known to occur during EVA and EVA training in the NBL. The primary objectives of this investigation were to: 1) document all known EVA glove related injuries and circumstances of these incidents, 2) determine likely risk factors, and 3) recommend interventions where possible that could be implemented in the current and future glove designs. METHODS: The investigation focused on the discomforts and injuries of U.S. crewmembers who had worn the pressurized Extravehicular Mobility Unit (EMU) spacesuit and experienced 4000 Series or Phase VI glove related incidents during 1981 to 2010 for either EVA ground training or in-orbit flight. We conducted an observational retrospective case-control investigation using 1) a literature review of known injuries, 2) data mining of crew injury, glove sizing, and hand anthropometry databases, 3) descriptive statistical analyses, and finally 4) statistical risk correlation and predictor analyses to better understand injury prevalence and potential causation. Specific predictor statistical analyses included use of principal component analyses (PCA), multiple logistic regression, and survival analyses (Cox proportional hazards regression). Results of these analyses were computed risk variables in the forms of odds ratios (likelihood of an injury occurring given the magnitude of a risk variable) and hazard ratios (likelihood of time to injury occurrence). Due to the exploratory nature of this investigation, we selected predictor variables significant at p=0.15. RESULTS: Through 2010, there have been a total of 330 NASA crewmembers, from which 96 crewmembers performed 322 EVAs during 1981-2010, resulting in 50 crewmembers being injured inflight and 44

  19. Tile survey seen during EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6412 (3 August 2005) --- Space Shuttle Discovery’s underside thermal protection tiles are featured in this image photographed by astronaut Stephen K. Robinson, STS-114 mission specialist, during the mission’s third session of extravehicular activities (EVA).

  20. 40 CFR 721.10519 - Perfluoroalkyl acrylate copolymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... as perfluoroalkyl acrylate copolymer (PMN P-11-63) is subject to reporting under this section for the... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Perfluoroalkyl acrylate copolymer... Specific Chemical Substances § 721.10519 Perfluoroalkyl acrylate copolymer (generic). (a) Chemical...

  1. 40 CFR 721.10519 - Perfluoroalkyl acrylate copolymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... as perfluoroalkyl acrylate copolymer (PMN P-11-63) is subject to reporting under this section for the... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Perfluoroalkyl acrylate copolymer... Specific Chemical Substances § 721.10519 Perfluoroalkyl acrylate copolymer (generic). (a) Chemical...

  2. A clinically authentic mouse model of enterovirus 71 (EV-A71)-induced neurogenic pulmonary oedema.

    PubMed

    Victorio, Carla Bianca Luena; Xu, Yishi; Ng, Qimei; Chua, Beng Hooi; Alonso, Sylvie; Chow, Vincent T K; Chua, Kaw Bing

    2016-06-30

    Enterovirus 71 (EV-A71) is a neurotropic virus that sporadically causes fatal neurologic illness among infected children. Animal models of EV-A71 infection exist, but they do not recapitulate in animals the spectrum of disease and pathology observed in fatal human cases. Specifically, neurogenic pulmonary oedema (NPE)-the main cause of EV-A71 infection-related mortality-is not observed in any of these models. This limits their utility in understanding viral pathogenesis of neurologic infections. We report the development of a mouse model of EV-A71 infection displaying NPE in severely affected animals. We inoculated one-week-old BALB/c mice with an adapted EV-A71 strain and identified clinical signs consistent with observations in human cases and other animal models. We also observed respiratory distress in some mice. At necropsy, we found their lungs to be heavier and incompletely collapsed compared to other mice. Serum levels of catecholamines and histopathology of lung and brain tissues of these mice strongly indicated onset of NPE. The localization of virally-induced brain lesions also suggested a potential pathogenic mechanism for EV-A71-induced NPE. This novel mouse model of virally-induced NPE represents a valuable resource for studying viral mechanisms of neuro-pathogenesis and pre-clinical testing of potential therapeutics and prophylactics against EV-A71-related neurologic complications.

  3. Self-assembly of model graft copolymers of agarose and weak polyelectrolyte-based amphiphilic diblock copolymers: controlled drug release and degradation.

    PubMed

    Muppalla, Ravikumar; Jewrajka, Suresh K; Prasad, Kamalesh

    2013-06-01

    Polysaccharide-based copolymers are promising biomaterials due to their biocompatibility and biodegradability. For potential biomedical applications the copolymer as a whole and all the degraded species must be biocompatible and easily removable from the system. In this regards, new model pH-responsive seaweed agarose (Agr) grafted with weak polyelectrolyte-based well-defined amphiphilic block copolymers ca. poly[(methyl methacrylate)-b-(2-dimethylamino)ethyl methacrylate)] (PMMA-b-PDMA) were designed and synthesized to study the self-assembly, degradation, and in vitro hydrophobic/hydrophilic drug release behavior. The graft copolymer solutions display extremely low critical micelle concentration (CMC) and form pH responsive stable micelles. The degradation study of the graft copolymer reveals that the entire degraded components are well soluble/dispersible in water due to formation of mixed micelles. The micelles are also strongly adsorbed on the mica surface owing to electrostatic interaction. One application of the graft copolymer micelles is that it can entrap both hydrophilic and poorly water soluble hydrophobic drugs effectively and exhibit slow release kinetics. The release kinetics of both the hydrophilic and poorly water soluble hydrophobic drugs change with pH as well as with the composition of the graft copolymer. Copyright © 2012 Wiley Periodicals, Inc.

  4. Astronaut Russell Schweickart inside simulator for EVA training

    NASA Image and Video Library

    1968-12-11

    S68-55391 (11 Dec. 1968) --- Astronaut Russell L. Schweickart, lunar module pilot of the Apollo 9 (Spacecraft 104/Lunar Module 3/Saturn 504) space mission, is seen inside Chamber "A," Space Environment Simulation Laboratory, Building 32, participating in dry run activity in preparation for extravehicular activity which is scheduled in Chamber "A." The purpose of the scheduled training is to familiarize the crewmen with the operation of EVA equipment in a simulated space environment. In addition, metabolic and workload profiles will be simulated on each crewman. Astronauts Schweickart and Alan L. Bean, backup lunar module pilot, are scheduled to receive thermal-vacuum training simulating Earth-orbital EVA.

  5. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the following...

  6. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the following...

  7. The micro conical system: Lessons learned from a successful EVA/robot-compatible mechanism

    NASA Technical Reports Server (NTRS)

    Gittleman, Mark; Johnston, Alistair

    1996-01-01

    The Micro Conical System (MCS) is a three-part, multi-purpose mechanical interface system used for acquiring and manipulating masses on-orbit by either extravehicular activity (EVA) or telerobotic means. The three components of the system are the micro conical fitting (MCF), the EVA micro tool (EMCT), and the Robot Micro Conical Tool (RMCT). The MCS was developed and refined over a four-year period. This period culminated with the delivery of 358 Class 1 and Class 2 micro conical fittings for the International Space Station and with its first use in space to handle a 1272 kg (2800 lbm) Spartan satellite (11000 times greater than the MCF mass) during an EVA aboard STS-63 in February, 1995. The micro conical system is the first successful EVA/robot-compatible mechanism to be demonstrated in the external environment aboard the U.S. Space Shuttle.

  8. Effective Teamwork: The EVA NBL Experience

    NASA Technical Reports Server (NTRS)

    Crocker, Lori

    2007-01-01

    This viewgraph presentation reviews the experience of improving the operation of the ExtraVehiclar Activity (EVA) Neutral Buoyancy Laboratory as a team of NASA employees and contractors. It reviews specific recommendations to use in turning a struggling organization around as a NASA/contractor team

  9. 21 CFR 177.1211 - Cross-linked polyacrylate copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... polyacrylate copolymers consist of: (1) The grafted copolymer of cross-linked sodium polyacrylate identified as... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Cross-linked polyacrylate copolymers. 177.1211... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1211 Cross-linked polyacrylate...

  10. 21 CFR 177.1211 - Cross-linked polyacrylate copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... polyacrylate copolymers consist of: (1) The grafted copolymer of cross-linked sodium polyacrylate identified as... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Cross-linked polyacrylate copolymers. 177.1211... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1211 Cross-linked polyacrylate...

  11. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true n-Alkylglutarimide/acrylic copolymers. 177.1060... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1060 n-Alkylglutarimide/acrylic copolymers. n-Alkylglutarimide/acrylic copolymers identified in this section may be safely used as articles...

  12. 21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials, containers...

  13. Schlegel during EVA 2

    NASA Image and Video Library

    2008-02-13

    S122-E-008315 (13 Feb. 2008) --- European Space Agency (ESA) astronaut Hans Schlegel, STS-122 mission specialist, participates in the mission's second scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 45-minute spacewalk, among other tasks, Schlegel and NASA astronaut Rex Walheim (out of frame), mission specialist, worked to replace a nitrogen tank used to pressurize the station's ammonia cooling system.

  14. Schlegel during EVA 2

    NASA Image and Video Library

    2008-02-13

    S122-E-008195 (13 Feb. 2008) --- European Space Agency (ESA) astronaut Hans Schlegel, STS-122 mission specialist, participates in the mission's second scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 45-minute spacewalk, among other tasks, Schlegel and NASA astronaut Rex Walheim (out of frame), mission specialist, worked to replace a nitrogen tank used to pressurize the station's ammonia cooling system.

  15. Schlegel during EVA 2

    NASA Image and Video Library

    2008-02-13

    S122-E-008325 (13 Feb. 2008) --- European Space Agency (ESA) astronaut Hans Schlegel, STS-122 mission specialist, participates in the mission's second scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 45-minute spacewalk, among other tasks, Schlegel and NASA astronaut Rex Walheim (out of frame), mission specialist, worked to replace a nitrogen tank used to pressurize the station's ammonia cooling system.

  16. Schlegel during EVA 2

    NASA Image and Video Library

    2008-02-13

    S122-E-008219 (13 Feb. 2008) --- European Space Agency (ESA) astronaut Hans Schlegel, STS-122 mission specialist, participates in the mission's second scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 45-minute spacewalk, among other tasks, Schlegel and NASA astronaut Rex Walheim (out of frame), mission specialist, worked to replace a nitrogen tank used to pressurize the station's ammonia cooling system.

  17. Light-emitting block copolymers composition, process and use

    DOEpatents

    Ferraris, John P.; Gutierrez, Jose J.

    2006-11-14

    Generally, and in one form, the present invention is a composition of light-emitting block copolymer. In another form, the present invention is a process producing a light-emitting block copolymers that intends polymerizing a first di(halo-methyl) aromatic monomer compound in the presence of an anionic initiator and a base to form a polymer and contacting a second di(halo-methyl) aromatic monomer compound with the polymer to form a homopolymer or block copolymer wherein the block copolymer is a diblock, triblock, or star polymer. In yet another form, the present invention is an electroluminescent device comprising a light-emitting block copolymer, wherein the electroluminescent device is to be used in the manufacturing of optical and electrical devices.

  18. Block Copolymers: Synthesis and Applications in Nanotechnology

    NASA Astrophysics Data System (ADS)

    Lou, Qin

    This study is focused on the synthesis and study of (block) copolymers using reversible deactivation radical polymerizations (RDRPs), including atom transfer radical polymerization (ATRP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. In particular, two primary areas of study are undertaken: (1) a proof-of-concept application of lithographic block copolymers, and (2) the mechanistic study of the deposition of titania into block copolymer templates for the production of well-ordered titania nanostructures. Block copolymers have the ability to undergo microphase separation, with an average size of each microphase ranging from tens to hundreds of nanometers. As such, block copolymers have been widely considered for nanotechnological applications over the past two decades. The development of materials for various nanotechnologies has become an increasingly studied area as improvements in many applications, such as those found in the semiconductor and photovoltaic industries are constantly being sought. Significant growth in developments of new synthetic methods ( i.e. RDRPs) has allowed the production of block copolymers with molecular (and sometimes atomic) definition. In turn, this has greatly expanded the use of block copolymers in nanotechnology. Herein, we describe the synthesis of statistical and block copolymers of 193 nm photolithography methacrylate and acrylate resist monomers with norbornyl and adamantyl moieties using RAFT polymerization.. For these resist (block) copolymers, the phase separation behaviors were examined by atomic force microscopy (AFM). End groups were removed from the polymers to avoid complications during the photolithography since RAFT end groups absorb visible light. Poly(glycidyl methacrylate-block-polystyrene) (PGMA-b-PS) was synthesize by ATRP and demonstrated that this block copolymer acts as both a lithographic UV (365 nm) photoresist and a self-assembly material. The PGMA segments can undergo cationic

  19. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be safely...

  20. 21 CFR 177.1312 - Ethylene-carbon monoxide copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-carbon monoxide copolymers. 177.1312... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1312 Ethylene-carbon monoxide copolymers. The ethylene-carbon monoxide copolymers identified in paragraph (a) of this section may be safely...

  1. Counteranion-Mediated Intrinsic Healing of Poly(ionic liquid) Copolymers.

    PubMed

    Guo, Panlong; Zhang, Houyu; Liu, Xiaokong; Sun, Junqi

    2018-01-17

    Fabrication of self-healing/healable materials using reversible interactions that are governed by their inherent chemical features is highly desirable because it avoids the introduction of extra groups that may present negative effects on their functions. The present study exploits the inherently featured electrostatic interactions of the ion pairs in polymeric ionic liquids (PILs) as the driving force to fabricate healable PIL copolymers. The healable PIL copolymers are fabricated through the copolymerization of the IL monomers with ethyl acrylate followed by the replacement of Br - counteranions with bulkier ones such as bis(trifluoromethanesulfonyl)imide (TFSI - ). Without modifying the chemical structures of the PIL moieties, the healing performance of the as-prepared PIL copolymers can be effectively mediated by their counteranions. The PIL copolymers that do not possess healability when paired with Br - counteranions become healable after exchanging the Br - counteranions with larger-sized ones (e.g., TFSI - ). The PIL copolymers paired with bulky counteranions exhibit enhanced chain mobility and highly reversible ion-pair interactions, which facilitate the healing process. The PIL copolymers paired with TFSI - anions can completely heal the damage/cut upon heating at 55 °C for 7.5 h. Meanwhile, the counteranions with larger sizes not only benefit the healing performance of the PIL copolymers but also enhance their ion conductivity. The ion conductivity of the PIL copolymers paired with TFSI - is an order of magnitude higher than that of the PIL copolymers paired with Br - . Therefore, the as-prepared healable PIL copolymers are potentially useful as solid electrolytes in PIL-based energy devices to improve their safety and reliability.

  2. Multi angle laser light scattering evaluation of field exposed thermoplastic photovoltaic encapsulant materials

    DOE PAGES

    Kempe, Michael D.; Miller, David C.; Wohlgemuth, John H.; ...

    2016-01-08

    As creep of polymeric materials is potentially a safety concern for photovoltaic modules, the potential for module creep has become a significant topic of discussion in the development of IEC 61730 and IEC 61215. To investigate the possibility of creep, modules were constructed, using several thermoplastic encapsulant materials, into thin-film mock modules and deployed in Mesa, Arizona. The materials examined included poly(ethylene)-co-vinyl acetate (EVA, including formulations both cross-linked and with no curing agent), polyethylene/polyoctene copolymer (PO), poly(dimethylsiloxane) (PDMS), polyvinyl butyral (PVB), and thermoplastic polyurethane (TPU). The absence of creep in this experiment is attributable to several factors of which themore » most notable one was the unexpected cross-linking of an EVA formulation without a cross-linking agent. It was also found that some materials experienced both chain scission and cross-linking reactions, sometimes with a significant dependence on location within a module. The TPU and EVA samples were found to degrade with cross-linking reactions dominating over chain scission. In contrast, the PO materials degraded with chain scission dominating over cross-linking reactions. Furthermore, we found no significant indications that viscous creep is likely to occur in fielded modules capable of passing the qualification tests, we note that one should consider how a polymer degrades, chain scission or cross-linking, in assessing the suitability of a thermoplastic polymer in terrestrial photovoltaic applications.« less

  3. Preparation of surfactant-free nanoparticles of methacrylic acid copolymers used for film coating.

    PubMed

    Nguyen, Cung An; Konan-Kouakou, Yvette Niamien; Allémann, Eric; Doelker, Eric; Quintanar-Guerrero, David; Fessi, Hatem; Gurny, Robert

    2006-07-28

    The aim of the present study was to prepare surfactant-free pseudolatexes of various methacrylic acid copolymers. These aqueous colloidal dispersions of polymeric materials for oral administration are intended for film coating of solid dosage forms or for direct manufacturing of nanoparticles. Nanoparticulate dispersions were produced by an emulsification-diffusion method involving the use of partially water-miscible solvents and the mutual saturation of the aqueous and organic phases prior to the emulsification in order to reduce the initial thermodynamic instability of the emulsion. Because of the self-emulsifying properties of the methacrylic acid copolymers, it was possible to prepare aqueous dispersions of colloidal size containing up to 30% wt/vol of Eudragit RL, RS, and E using 2-butanone or methyl acetate as partially water-miscible solvents, but without any surfactant. However, in the case of the cationic Eudragit E, protonation of the tertiary amine groups by acidification of the aqueous phase was necessary to improve the emulsion stability in the absence of surfactant and subsequently to prevent droplet coalescence during evaporation. In addition, a pseudolatex of Eudragit E was used to validate the coating properties of the formulation for solid dosage forms. Film-coated tablets of quinidine sulfate showed a transparent glossy continuous film that was firmly attached to the tablet. The dissolution profile of quinidine sulfate from the tablets coated with the Eudragit E pseudolatex was comparable to that of tablets coated with an acetonic solution of Eudragit E. Furthermore, both types of coating ensured similar taste masking. The emulsification-evaporation method used was shown to be appropriate for the preparation of surfactant-free colloidal dispersions of the 3 types of preformed methacrylic acid copolymers; the dispersions can subsequently be used for film coating of solid dosage forms.

  4. Melt structure and self-nucleation of ethylene copolymers

    NASA Astrophysics Data System (ADS)

    Alamo, Rufina G.

    A strong memory effect of crystallization has been observed in melts of random ethylene copolymers well above the equilibrium melting temperature. These studies have been carried out by DSC, x-ray, TEM and optical microscopy on a large number of model, narrow, and broad copolymers with different comonomer types and contents. Melt memory is correlated with self-seeds that increase the crystallization rate of ethylene copolymers. The seeds are associated with molten ethylene sequences from the initial crystals that remain in close proximity and lower the nucleation barrier. Diffusion of all sequences to a randomized melt state is a slow process, restricted by topological chain constraints (loops, knots, and other entanglements) that build in the intercrystalline region during crystallization. Self-seeds dissolve above a critical melt temperature that demarcates homogeneity of the copolymer melt. There is a critical threshold level of crystallinity to observe the effect of melt memory on crystallization rate, thus supporting the correlation between melt memory and the change in melt structure during copolymer crystallization. Unlike binary blends, commercial ethylene-1-alkene copolymers with a range in inter-chain comonomer composition between 1 and about 15 mol % display an inversion of the crystallization rate in a range of melt temperatures where narrow copolymers show a continuous acceleration of the rate. With decreasing the initial melt temperature, broadly distributed copolymers show enhanced crystallization followed by a decrease of crystallization rate. The inversion demarcates the onset of liquid-liquid phase separation (LLPS) and a reduction of self-nuclei due to the strong thermodynamic drive for molecular segregation inside the binodal. The strong effect of melt memory on crystallization rate can be used to identify liquid-liquid phase separation in broadly distributed copolymers, and offers strategies to control the state of copolymer melts in ways of

  5. Astronaut Kathryn Sullivan checks SIR-B antenna during EVA

    NASA Image and Video Library

    1984-10-11

    41G-13-032 (11 Oct. 1984) --- Astronaut Kathryn D. Sullivan checks the latch of the SIR-B antenna in the space shuttle Challenger's open cargo bay during her historic extravehicular activity (EVA) on Oct. 11, 1984. Earlier, America's first woman to perform an EVA and astronaut David C. Leestma, participated in an in-space simulation of refueling a spacecraft in orbit. The Orbital Refueling System (ORS) is just beyond the astronaut mission specialist's helmet. To the left is the Large Format Camera (LFC). The LFC and ORS are stationed on a device called the Mission Peculiar Support Structure (MPESS). Crew members consisted of astronauts Robert L. Crippen, commander; Jon A. McBride, pilot; along with Kathryn D. Sullivan, Sally K. Ride, and David D. Leestma, all mission specialists; and Canadian astronaut Marc Garneau and Paul D. Scully-Power, both payload specialist. EDITOR'S NOTE: The STS-41G mission had the first American female EVA (Sullivan); first seven-person crew; first orbital fuel transfer; and the first Canadian (Garneau).

  6. Hemocompatibility evaluation in vitro of methoxy polyethyleneglycol-polycaprolactone copolymer solutions.

    PubMed

    Hu, Qian; Zhang, Yi; Wang, Changyong; Xu, Jiake; Wu, Jianping; Liu, Zonghua; Xue, Wei

    2016-03-01

    Amphiphilic block copolymer methoxy polyethyleneglycol-polycaprolactone (mPEG-PCL) has attracted interest in the biomedical field, due to its water solubility and biodegradability. Nevertheless, the blood safety of mPEG-PCL copolymers has not been investigated in detail. Because mPEG-PCL copolymers introduced in vivo would inevitably interact with blood tissue, an investigation of possible interactions of mPEG-PCL with key blood components is crucial. We studied the effects of two mPEG-PCL copolymer solutions on blood coagulation, the morphology and lysis of human red blood cells (RBCs), the structure of plasma fibrinogen, complement activation, and platelet aggregation. We found that higher concentrations of the mPEG-PCL copolymers impaired blood clotting, and the copolymers had little impact on the morphology or lysis of RBCs. From the spectroscopy results, the copolymers affected the local microstructure of fibrinogen. The copolymers significantly activated the complement system in a concentration-dependent way. At higher concentrations, the copolymers impaired platelet aggregation, which may have been mediated by an inhibition of the arachidonic acid pathway. These findings provide important information that may be useful for the molecular design and biomedical applications of mPEG-PCL copolymers. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 802-812, 2016. © 2016 Wiley Periodicals, Inc.

  7. Application of EVA guidelines and design criteria. Volume 2: EVA workstation conceptual designs

    NASA Technical Reports Server (NTRS)

    Brown, N. E.

    1973-01-01

    Several EV workstation concepts were developed and are documented. The workstation concepts were developed following a comprehensive analysis of potential EV missions, functions, and tasks as interpreted from NASA and contractor space shuttle and space station studies, mission models, and related reports. The design of a versatile, portable EVA workstation is aimed at reducing the design and development costs for each mission and aiding in the development of on-orbit serviceable payloads.

  8. Amphiphilic block copolymer membrane for vanadium redox flow battery

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Sylvia, James M.; Jacob, Monsy M.; Peramunage, Dharmasena

    2013-11-01

    An amphiphilic block copolymer comprised of hydrophobic polyaryletherketone (PAEK) and hydrophilic sulfonated polyaryletherketone (SPAEK) blocks has been synthesized and characterized. A membrane prepared from the block copolymer is used as the separator in a single cell vanadium redox flow battery (VRB). The proton conductivity, mechanical property, VO2+ permeability and single VRB cell performance of this block copolymer membrane are investigated and compared to Nafion™ 117. The block copolymer membrane showed significantly improved vanadium ion selectivity, higher mechanical strength and lower conductivity than Nafion™ 117. The VRB containing the block copolymer membrane exhibits higher coulombic efficiency and similar energy efficiency compared to a VRB using Nafion™ 117. The better vanadium ion selectivity of the block copolymer membrane has led to a much smaller capacity loss during 50 charge-discharge cycles for the VRB.

  9. Periodic nanostructures from self assembled wedge-type block-copolymers

    DOEpatents

    Xia, Yan; Sveinbjornsson, Benjamin R.; Grubbs, Robert H.; Weitekamp, Raymond; Miyake, Garret M.; Piunova, Victoria; Daeffler, Christopher Scot

    2015-06-02

    The invention provides a class of wedge-type block copolymers having a plurality of chemically different blocks, at least a portion of which incorporates a wedge group-containing block providing useful properties. For example, use of one or more wedge group-containing blocks in some block copolymers of the invention significantly inhibits chain entanglement and, thus, the present block copolymers materials provide a class of polymer materials capable of efficient molecular self-assembly to generate a range of structures, such as periodic nanostructures and microstructures. Materials of the present invention include copolymers having one or more wedge group-containing blocks, and optionally for some applications copolymers also incorporating one or more polymer side group-containing blocks. The present invention also provides useful methods of making and using wedge-type block copolymers.

  10. Tile survey taken during EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6366 (3 August 2005) --- Space Shuttle Discovery’s underside is featured in this image photographed by astronaut Stephen K. Robinson, STS-114 mission specialist, during today’s extravehicular activities (EVA). Robinson’s shadow is visible on the thermal protection tiles.

  11. Injectable biodegradable temperature-responsive PLGA-PEG-PLGA copolymers: synthesis and effect of copolymer composition on the drug release from the copolymer-based hydrogels.

    PubMed

    Qiao, Mingxi; Chen, Dawei; Ma, Xichen; Liu, Yanjun

    2005-04-27

    Injectable biodegradable temperature-responsive poly(DL-lactide-co-glycolide-b-ethylene glycol-b-DL-lactide-co-glycolide) (PLGA-PEG-PLGA) triblock copolymers with DL-lactide/glycolide molar ratio ranging from 6/1 to 15/l were synthesized from monomers of DL-lactide, glycolide and polyethylene glycol and characterized by 1H NMR. The resulting copolymers are soluble in water to form free flowing fluid at room temperature but become hydrogels at body temperature. The hydrophobicity of the copolymer increased with the increasing of DL-lactide/glycolide molar ratio. In vitro dissolution studies with two different hydrophobic drugs (5-fluorouracil and indomethacin) were performed to study the effect of DL-lactide/glycolide molar ratio on drug release and to elucidate drug release mechanism. The release mechanism for hydrophilic 5-fluorouracil was diffusion-controlled, while hydrophobic indomethacin showed an biphasic profile comprising of an initial diffusion-controlled stage followed by the hydrogel erosion-dominated stage. The effect of DL-lactide/glycolide molar ratio on drug release seemed to be dependent on the drug release mechanism. It has less effect on the drug release during the diffusion-controlled stage, but significantly affected drug release during the hydrogel erosion-controlled stage. Compared with ReGel system, the synthesized copolymers showed a higher gelation temperature and longer period of drug release. The copolymers can solubilize the hydrophobic indomethacin and the solubility (13.7 mg/ml) was increased 3425-fold compared to that in water (4 microg/ml, 25 degrees C). Two methods of physical mixing method and solvent evaporation method were used for drug solubilization and the latter method showed higher solubilization efficiency.

  12. Characterization of the Radiation Shielding Properties of US andRussian EVA Suits

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Benton, E.R.; Benton, E.V.; Frank, A.L.

    2001-10-26

    Reported herein are results from the Eril Research, Inc.(ERI) participationin the NASA Johnson Space Center sponsored studycharacterizing the radiation shielding properties of the two types ofspace suit that astronauts are wearing during the EVA on-orbit assemblyof the International Space Station (ISS). Measurements using passivedetectors were carried out to assess the shielding properties of the USEMU Suit and the Russian Orlan-M suit during irradiations of the suitsand a tissue equivalent phantom to monoenergetic proton and electronbeams at the Loma Linda University Medical Center (LLUMC). Duringirradiations of 6 MeV electrons and 60 MeV protons, absorbed dose as afunction of depth was measuredmore » using TLDs exposed behind swatches of thetwo suit materials and inside the two EVA helmets. Considerable reductionin electron dosewas measured behind all suit materials in exposures to 6MeV electrons. Slowing of the proton beam in the suit materials led to anincrease in dose measured in exposures to 60 MeV protons. During 232 MeVproton irradiations, measurements were made with TLDs and CR-39 PNTDs atfive organ locations inside a tissue equivalent phantom, exposed bothwith and without the two EVA suits. The EVA helmets produce a 13 to 27percent reduction in total dose and a 0 to 25 percent reduction in doseequivalent when compared to measurements made in the phantom head alone.Differences in dose and dose equivalent between the suit and non-suitirradiations forthe lower portions of the two EVA suits tended to besmaller. Proton-induced target fragmentation was found to be asignificant source of increased dose equivalent, especially within thetwo EVA helmets, and average quality factor inside the EMU and Orlan-Mhelmets was 2 to 14 percent greater than that measured in the barephantom head.« less

  13. Non-Venting Thermal and Humidity Control for EVA Suits

    NASA Technical Reports Server (NTRS)

    Izenson, Mike; Chen, Weibo; Bue, Grant

    2011-01-01

    Future EVA suits need processes and systems to control internal temperature and humidity without venting water to the environment. This paper describes an absorption-based cooling and dehumidification system as well as laboratory demonstrations of the key processes. There are two main components in the system: an evaporation cooling and dehumidification garment (ECDG) that removes both sensible heat and latent heat from the pressure garment, and an absorber radiator that absorbs moisture and rejects heat to space by thermal radiation. This paper discusses the overall design of both components, and presents recent data demonstrating their operation. We developed a design and fabrication approach to produce prototypical heat/water absorbing elements for the ECDG, and demonstrated by test that these elements could absorb heat and moisture at a high flux. Proof-of-concept tests showed that an ECDG prototype absorbs heat and moisture at a rate of 85 W/ft under conditions that simulate operation in an EVA suit. The heat absorption was primarily due to direct absorption of water vapor. It is possible to construct large, flexible, durable cooling patches that can be incorporated into a cooling garment with this system. The proof-of-concept test data was scaled to calculate area needed for full metabolic loads, thus showing that it is feasible to use this technology in an EVA suit. Full-scale, lightweight absorber/radiator modules have also been built and tested. They can reject heat at a flux of 33 W/ft while maintaining ECDG operation at conditions that will provide a cool and dry environment inside the EVA suit.

  14. EB-promoted recycling of waste tire rubber with polyolefins

    NASA Astrophysics Data System (ADS)

    Mészáros, László; Bárány, Tamás; Czvikovszky, Tibor

    2012-09-01

    Despite the fact that more and more methods and solutions are used in the recycling of polymers, there are still some problems, especially in the recycling of cross-linked materials such as rubber. Usually the biggest problem is the lack of compatibility between the cross-linked rubber and the thermoplastic matrix. In this study we applied ground tire rubber (GTR) as recycled material. The GTR was embedded into polyethylene (PE) and polyethylene/ethylene-vinyl acetate copolymer (PE/EVA) matrices. In order to increase the compatibility of the components electron beam (EB) irradiation was applied. The results showed that the irradiation has a beneficial effect on the polymer-GTR interfacial connection. The EB treatment increased not only the tensile strength but also the elongation at break. The irradiation had also positive effect on the impact strength properties.

  15. Electrostatic Discharge Issues in International Space Station Program EVAs

    NASA Technical Reports Server (NTRS)

    Bacon, John B.

    2009-01-01

    EVA activity in the ISS program encounters several dangerous ESD conditions. The ISS program has been aggressive for many years to find ways to mitigate or to eliminate the associated risks. Investments have included: (1) Major mods to EVA tools, suit connectors & analytical tools (2) Floating Potential Measurement Unit (3) Plasma Contactor Units (4) Certification of new ISS flight attitudes (5) Teraflops of computation (6) Thousands of hours of work by scores of specialists (7) Monthly management attention at the highest program levels. The risks are now mitigated to a level that is orders of magnitude safer than prior operations

  16. STS-64 Extravehicular activity (EVA) training view in WETF

    NASA Image and Video Library

    1994-08-10

    S94-39775 (August 1994) --- Astronaut Carl J. Meade, STS-64 mission specialist, listens to ground monitors during a simulation of a spacewalk scheduled for his September mission. Meade, who shared the rehearsal in the Johnson Space Center's (JSC) Weightless Environment Training Facility (WET-F) pool with crewmate astronaut Mark C. Lee, is equipped with a training version of new extravehicular activity (EVA) hardware called the Simplified Aid for EVA Rescue (SAFER) system. The hardware includes a mobility-aiding back harness and a chest-mounted hand control module. Photo credit: NASA or National Aeronautics and Space Administration

  17. STS-64 Extravehicular activity (EVA) training view in WETF

    NASA Image and Video Library

    1994-08-10

    S94-39762 (August 1994) --- Astronaut Carl J. Meade, STS-64 mission specialist, listens to ground monitors prior to a simulation of a spacewalk scheduled for his September mission. Meade, who shared the rehearsal in Johnson Space Center's (JSC) Weightless Environment Training Facility (WET-F) pool with crewmate astronaut Mark C. Lee (out of frame), is equipped with a training version of new extravehicular activity (EVA) hardware called the Simplified Aid for EVA Rescue (SAFER) system. The hardware includes a mobility-aiding back harness and a chest-mounted hand control module. Photo credit: NASA or National Aeronautics and Space Administration

  18. EVA - A Textual Data Processing Tool.

    ERIC Educational Resources Information Center

    Jakopin, Primoz

    EVA, a text processing tool designed to be self-contained and useful for a variety of languages, is described briefly, and its extensive coded character set is illustrated. Features, specifications, and database functions are noted. Its application in development of a Slovenian literary dictionary is also described. (MSE)

  19. Oxygen plasma resistant phosphine oxide containing imide/arylene copolymers

    NASA Technical Reports Server (NTRS)

    Jensen, Brian J.

    1993-01-01

    A series of oxygen plasma resistant imide/arylene ether copolymers were prepared by reacting anhydride-terminated poly(amide acids) and amine-terminated polyarylene ethers containing phosphine oxide units. Inherent viscosities for these copolymers ranged from 0.42 to 0.80 dL/g. After curing, the resulting copolymers had glass transition temperatures ranging from 224 C to 228 C. Solution cast films of the block copolymers were tough and flexible with tensile strength, tensile moduli, and elongation at break up to 16.1 ksi, 439 ksi, and 23 percent, respectively at 25 C and 9.1 ksi, 308 ksi and 97 percent, respectively at 150 C. The copolymers show a significant improvement in resistance to oxygen plasma when compared to the commercial polyimide Kapton. The imide/arylene ether copolymers containing phosphine oxide units are suitable as coatings, films, adhesives, and composite matrices.

  20. Results of EVA/mobile transporter space station truss assembly tests

    NASA Technical Reports Server (NTRS)

    Watson, Judith J.; Heard, Walter L., Jr.; Bush, Harold G.; Lake, M. S.; Jensen, J. K.; Wallsom, R. E.; Phelps, J. E.

    1988-01-01

    Underwater neutral buoyance tests were conducted to evaluate the use of a Mobile Transporter concept in conjunction with EVA astronauts to construct the Space Station Freedom truss structure. A three-bay orthogonal tetrahedral truss configuration with a 15 foot square cross section was repeatedly assembled by a single pair of pressure suited test subjects working from the Mobile Transporter astronaut positioning devices (mobile foot restraints). The average unit assembly time (which included integrated installation of utility trays) was 27.6 s/strut, or 6 min/bay. The results of these tests indicate that EVA assembly of space station size structures can be significantly enhanced when using a Mobile Transporter equipped with astronaut positioning devices. Rapid assembly time can be expected and are dependent primarily on the rate of translation permissible for on-orbit operations. The concept used to demonstate integrated installation of utility trays requires minimal EVA handling and consequentially, as the results show, has little impact on overall assembly time.

  1. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035177 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers. Parts of solar array panels on the orbital outpost are visible in the background,

  2. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035198 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers. A section of the space station is visible in the reflections in his helmet visor.

  3. Russian EVA 35

    NASA Image and Video Library

    2013-08-22

    ISS036-E-035200 (22 Aug. 2013) --- Russian cosmonaut Alexander Misurkin, Expedition 36 flight engineer, attired in a Russian Orlan spacesuit, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 58-minute spacewalk, Misurkin and Russian cosmonaut Fyodor Yurchikhin (out of frame) completed the replacement of a laser communications experiment with a new platform for a small optical camera system, the installation of new spacewalk aids and an inspection of antenna covers. A section of the space station is visible in the reflections in his helmet visor.

  4. Russian EVA-31

    NASA Image and Video Library

    2012-08-20

    ISS032-E-020683 (20 Aug. 2012) --- Russian cosmonaut Gennady Padalka, Expedition 32 commander, participates in a session of extravehicular activity (EVA) to continue outfitting the International Space Station. During the five-hour, 51-minute spacewalk, Padalka and Russian cosmonaut Yuri Malenchenko (out of frame), flight engineer, moved the Strela-2 cargo boom from the Pirs docking compartment to the Zarya module to prepare Pirs for its eventual replacement with a new Russian multipurpose laboratory module. The two spacewalking cosmonauts also installed micrometeoroid debris shields on the exterior of the Zvezda service module and deployed a small science satellite.

  5. Dynamics, control and sensor issues pertinent to robotic hands for the EVA retriever system

    NASA Technical Reports Server (NTRS)

    Mclauchlan, Robert A.

    1987-01-01

    Basic dynamics, sensor, control, and related artificial intelligence issues pertinent to smart robotic hands for the Extra Vehicular Activity (EVA) Retriever system are summarized and discussed. These smart hands are to be used as end effectors on arms attached to manned maneuvering units (MMU). The Retriever robotic systems comprised of MMU, arm and smart hands, are being developed to aid crewmen in the performance of routine EVA tasks including tool and object retrieval. The ultimate goal is to enhance the effectiveness of EVA crewmen.

  6. Rod-Coil Block Polyimide Copolymers

    NASA Technical Reports Server (NTRS)

    Meador, Mary Ann B. (Inventor); Kinder, James D. (Inventor)

    2005-01-01

    This invention is a series of rod-coil block polyimide copolymers that are easy to fabricate into mechanically resilient films with acceptable ionic or protonic conductivity at a variety of temperatures. The copolymers consist of short-rigid polyimide rod segments alternating with polyether coil segments. The rods and coil segments can be linear, branched or mixtures of linear and branched segments. The highly incompatible rods and coil segments phase separate, providing nanoscale channels for ion conduction. The polyimide segments provide dimensional and mechanical stability and can be functionalized in a number of ways to provide specialized functions for a given application. These rod-coil black polyimide copolymers are particularly useful in the preparation of ion conductive membranes for use in the manufacture of fuel cells and lithium based polymer batteries.

  7. Processing research and development of 'green' polymer nanoclay composites containing a polyhydroxybutyrate, vinyl acetates, and modified montmorillonite clay

    NASA Astrophysics Data System (ADS)

    McKirahan, James N., Jr.

    The purpose of this research was to determine the feasibility of direct melt-blending (intercalation) montmorillonite nanoclay to polyhydroxybutyrate along with vinyl acetate, at different weight percentages, to enhance plasticization using typical plastic processing equipment and typical processing methodology. The purpose was to determine and compare the specific mechanical properties of tensile strength and flexural strength developed as a result from this processing. Single screw and twin screw extrusion, Banbury mixer compounding, and compression molding were used to intercalate montmorillonite, and for sample preparation purposes, to test tensile and flexural strength of the resultant polymer clay nanocomposites (PCN). Results indicate Polyhydroxybutyrate and Ethylene vinyl acetate, and weight percentages of 70%, 65% and 60% PHB, and 15%, 20%, and 25% of EVA, respectively, influenced mechanical properties. The resultant materials remained in a mostly amorphous state. The nanoclay, at specific weight percentage of 10%, acted as an antimicrobial and preservative for the materials produced during the research. The intention of the research was to promote knowledge and understanding concerning these materials and processes so technology transfer regarding the use, mechanical properties, manufacture, and process ability of these bio-friendly materials to academia, industry, and society can occur.

  8. ASTRONAUT KERWIN, JOSEPH P. - EXTRAVEHICULAR ACTIVITY (EVA) - SKYLAB (SL)-2

    NASA Image and Video Library

    1973-06-01

    S73-27562 (June 1973) --- Scientist-astronaut Joseph P. Kerwin, Skylab 2 science pilot, performs extravehicular activity (EVA) at the Skylab 1 and 2 space station cluster in Earth orbit, as seen in this reproduction taken from a color television transmission made by a TV camera aboard the station. Kerwin is just outside the Airlock Module. Kerwin assisted astronaut Charles Conrad Jr., Skylab 2 commander, during the successful EVA attempt to free the stuck solar array system wing on the Orbital Workshop. Photo credit: NASA

  9. EVA Physiology, Systems and Performance [EPSP] Project

    NASA Technical Reports Server (NTRS)

    Gernhardt, Michael L.

    2010-01-01

    This viewgraph presentation gives a general overview of the biomedical and technological challenges of Extravehicular Activity (EVA). The topics covered include: 1) Prebreathe Protocols; 2) Lunar Suit Testing and Development; and 3) Lunar Electric Rover and Exploration Operations Concepts.

  10. Interfacing with an EVA Suit

    NASA Technical Reports Server (NTRS)

    Ross, Amy

    2011-01-01

    A NASA spacesuit under the EVA Technology Domain consists of a suit system; a PLSS; and a Power, Avionics, and Software (PAS) system. Ross described the basic functions, components, and interfaces of the PLSS, which consists of oxygen, ventilation, and thermal control subsystems; electronics; and interfaces. Design challenges were reviewed from a packaging perspective. Ross also discussed the development of the PLSS over the last two decades.

  11. Block Copolymer Membranes for Biofuel Purification

    NASA Astrophysics Data System (ADS)

    Evren Ozcam, Ali; Balsara, Nitash

    2012-02-01

    Purification of biofuels such as ethanol is a matter of considerable concern as they are produced in complex multicomponent fermentation broths. Our objective is to design pervaporation membranes for concentrating ethanol from dilute aqueous mixtures. Polystyrene-b-polydimethylsiloxane-b-polystyrene block copolymers were synthesized by anionic polymerization. The polydimethylsiloxane domains provide ethanol-transporting pathways, while the polystyrene domains provide structural integrity for the membrane. The morphology of the membranes is governed by the composition of the block copolymer while the size of the domains is governed by the molecular weight of the block copolymer. Pervaporation data as a function of these two parameters will be presented.

  12. Schlegel during EVA 2

    NASA Image and Video Library

    2008-02-13

    S122-E-008221 (13 Feb. 2008) --- European Space Agency (ESA) astronaut Hans Schlegel, STS-122 mission specialist, works on the new Columbus laboratory as he participates in the mission's second scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the six-hour, 45-minute spacewalk, among other tasks, Schlegel and NASA astronaut Rex Walheim (out of frame), mission specialist, worked to replace a nitrogen tank used to pressurize the station's ammonia cooling system.

  13. Kondratyev during EVA 28

    NASA Image and Video Library

    2011-02-16

    ISS026-E-027361 (16 Feb. 2011) --- Russian cosmonaut Dmitry Kondratyev, Expedition 26 flight engineer, wearing a Russian Orlan-MK spacesuit, participates in a session of extravehicular activity (EVA) focused on the installation of two scientific experiments outside the Zvezda Service Module of the International Space Station. During the four-hour, 51-minute spacewalk, Kondratyev and Russian cosmonaut Oleg Skripochka (out of frame), flight engineer, installed a pair of earthquake and lightning sensing experiments and retrieved a pair of spacecraft material evaluation panels.

  14. Kondratyev during EVA 28

    NASA Image and Video Library

    2011-02-16

    ISS026-E-027368 (16 Feb. 2011) --- Russian cosmonaut Dmitry Kondratyev, Expedition 26 flight engineer, wearing a Russian Orlan-MK spacesuit, participates in a session of extravehicular activity (EVA) focused on the installation of two scientific experiments outside the Zvezda Service Module of the International Space Station. During the four-hour, 51-minute spacewalk, Kondratyev and Russian cosmonaut Oleg Skripochka (out of frame), flight engineer, installed a pair of earthquake and lightning sensing experiments and retrieved a pair of spacecraft material evaluation panels.

  15. 40 CFR 721.10213 - Polyether polyester copolymer phosphate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polyether polyester copolymer... Specific Chemical Substances § 721.10213 Polyether polyester copolymer phosphate (generic). (a) Chemical... as polyether polyester copolymer phosphate (PMN P-09-253) is subject to reporting under this section...

  16. 40 CFR 721.336 - Perfluoroalkylethyl acrylate copolymer (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... as a perfluoroalkylethyl acrylate copolymer (PMN P-94-241) is subject to reporting under this section... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Perfluoroalkylethyl acrylate copolymer... Specific Chemical Substances § 721.336 Perfluoroalkylethyl acrylate copolymer (generic name). (a) Chemical...

  17. 40 CFR 721.336 - Perfluoroalkylethyl acrylate copolymer (generic name).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... as a perfluoroalkylethyl acrylate copolymer (PMN P-94-241) is subject to reporting under this section... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Perfluoroalkylethyl acrylate copolymer... Specific Chemical Substances § 721.336 Perfluoroalkylethyl acrylate copolymer (generic name). (a) Chemical...

  18. 40 CFR 721.336 - Perfluoroalkylethyl acrylate copolymer (generic name).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... as a perfluoroalkylethyl acrylate copolymer (PMN P-94-241) is subject to reporting under this section... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Perfluoroalkylethyl acrylate copolymer... Specific Chemical Substances § 721.336 Perfluoroalkylethyl acrylate copolymer (generic name). (a) Chemical...

  19. 40 CFR 721.336 - Perfluoroalkylethyl acrylate copolymer (generic name).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... as a perfluoroalkylethyl acrylate copolymer (PMN P-94-241) is subject to reporting under this section... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Perfluoroalkylethyl acrylate copolymer... Specific Chemical Substances § 721.336 Perfluoroalkylethyl acrylate copolymer (generic name). (a) Chemical...

  20. Spaceborne construction and operations planning - Decision rules for selecting EVA, telerobot, and combined work-systems

    NASA Technical Reports Server (NTRS)

    Smith, Jeffrey H.

    1992-01-01

    An approach is presented for selecting an appropriate work-system for performing construction and operations tasks by humans and telerobots. The decision to use extravehicular activity (EVA) performed by astronauts, extravehicular robotics (EVR), or a combination of EVA and EVR is determined by the ratio of the marginal costs of EVA, EVR, and IVA. The approach proposed here is useful for examining cost trade-offs between tasks and performing trade studies of task improvement techniques (human or telerobotic).

  1. Tile survey seen during EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6387 (3 August 2005) --- A close-up view of a portion of the thermal protection tiles on Space Shuttle Discovery’s underside is featured in this image photographed by astronaut Stephen K. Robinson, STS-114 mission specialist, during the mission’s third session of extravehicular activities (EVA).

  2. Injectible bodily prosthetics employing methacrylic copolymer gels

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  3. Reversible geling co-polymer and method of making

    DOEpatents

    Gutowska, Anna

    2005-12-27

    The present invention is a thereapeutic agent carrier having a thermally reversible gel or geling copolymer that is a linear random copolymer of an [meth-]acrylamide derivative and a hydrophilic comonomer, wherein the linear random copolymer is in the form of a plurality of linear chains having a plurality of molecular weights greater than or equal to a minimum geling molecular weight cutoff and a therapeutic agent.

  4. Biosensors for EVA: Muscle Oxygen and pH During Walking, Running and Simulated Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Lee, S. M. C.; Ellerby, G.; Scott, P.; Stroud, L.; Norcross, J.; Pesholov, B.; Zou, F.; Gernhardt, M.; Soller, B.

    2009-01-01

    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO2 on the leg during cycling. Our NSBRI-funded project is looking to extend this methodology to examine activities which more appropriately represent EVA activities, such as walking and running and to better understand factors that determine the metabolic cost of exercise in both normal and lunar gravity. Our 4 year project specifically addresses risk: ExMC 4.18: Lack of adequate biomedical monitoring capability for Constellation EVA Suits and EPSP risk: Risk of compromised EVA performance and crew health due to inadequate EVA suit systems.

  5. Correlation between surface carbon concentration and adhesive strength at the Si cell/EVA interface in a PV module

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dhere, N.G.; Wollam, M.E.; Gadre, K.S.

    1997-12-31

    Silicon solar cell/EVA composite is being studied with an objective to further improve the manufacturing technology of PV modules. Sample extraction and adhesion strength measurement process has been modified. Silicon and EVA samples were extracted from solar cells of new and field-deployed modules. Optical microscopy, SEM, and AES of samples from new modules revealed EVA islands covering most of the silicon cell surface indicating a cohesive failure. A good correlation was observed between the adhesive strength and surface concentration of carbon. A low carbon concentration which indicated less EVA clinging to cell surface always resulted in low adhesive strengths. Themore » correlation provides a simple technique for inferring properties of EVA.« less

  6. Astronaut Dale Gardner holds up for sale sign after EVA

    NASA Image and Video Library

    1984-11-14

    51A-104-049 (14 Nov. 1984) --- Astronaut Dale A. Gardner, having just completed the major portion of his second extravehicular activity (EVA) period in three days aboard the Earth-orbiting Discovery, holds up a for sale sign. Astronaut Joseph P. Allen IV, who also participated in the two EVA, is reflected in Gardner's helmet visor. A portion of each of two recovered satellites is in lower right corner, with Westar nearer Discovery's aft. Dr. Allen, standing on the mobile foot restraint, connected to the remote manipulator system. Photo credit: NASA

  7. EVA Roadmap: New Space Suit for the 21st Century

    NASA Technical Reports Server (NTRS)

    Yowell, Robert

    1998-01-01

    New spacesuit design considerations for the extra vehicular activity (EVA) of a manned Martian exploration mission are discussed. Considerations of the design includes:(1) regenerable CO2 removal, (2) a portable life support system (PLSS) which would include cryogenic oxygen produced from in-situ manufacture, (3) a power supply for the EVA, (4) the thermal control systems, (5) systems engineering, (5) space suit systems (materials, and mobility), (6) human considerations, such as improved biomedical sensors and astronaut comfort, (7) displays and controls, and robotic interfaces, such as rovers, and telerobotic commands.

  8. Medical, Psychophysiological, and Human Performance Problems During Extended EVA

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In this session, Session JP1, the discussion focuses on the following topics: New Developments in the Assessment of the Risk of Decompression Sickness in Null Gravity During Extravehicular Activity; The Dynamic of Physiological Reactions of Cosmonauts Under the Influence of Repeated EVA Workouts, The Russian Experience; Medical Emergencies in Space; The Evolution from 'Physiological Adequacy' to 'Physiological Tuning'; Five Zones of Symmetrical and Asymmetrical Conflicting Temperatures on the Human Body, Physiological Consequences; Human Performance and Subjective Perception in Nonuniform Thermal Conditions; The Hand as a Control System, Implications for Hand-Finger Dexterity During Extended EVA; and Understanding the Skill of Extravehicular Mass Handling.

  9. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

    Liu, Changsheng; Li, Qingbo

    2005-08-09

    This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

  10. Simplified Abrasion Test Methodology for Candidate EVA Glove Lay-Ups

    NASA Technical Reports Server (NTRS)

    Rabel, Emily; Aitchison, Lindsay

    2015-01-01

    During the Apollo Program, space suit outer-layer fabrics were badly abraded after performing just a few extravehicular activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots that penetrated the outer-layer fabric into the thermal protection layers after less than 8 hrs of surface operations. Current plans for the exploration planetary space suits require the space suits to support hundreds of hours of EVA on a lunar or Martian surface, creating a challenge for space suit designers to utilize materials advances made over the last 40 years and improve on the space suit fabrics used in the Apollo Program. Over the past 25 years the NASA Johnson Space Center Crew and Thermal Systems Division has focused on tumble testing as means of simulating wear on the outer layer of the space suit fabric. Most recently, in 2009, testing was performed on 4 different candidate outer layers to gather baseline data for future use in design of planetary space suit outer layers. In support of the High Performance EVA Glove Element of the Next Generation Life Support Project, testing a new configuration was recently attempted in which require 10% of the fabric per replicate of that need in 2009. The smaller fabric samples allowed for reduced per sample cost and flexibility to test small samples from manufacturers without the overhead to have a production run completed. Data collected from this iteration was compared to that taken in 2009 to validate the new test method. In addition the method also evaluated the fabrics and fabric layups used in a prototype thermal micrometeoroid garment (TMG) developed for EVA gloves under the NASA High Performance EVA Glove Project. This paper provides a review of previous abrasion studies on space suit fabrics, details methodologies used for abrasion testing in this particular study, results of the validation study, and results of the TMG testing.

  11. Dimensionally Stable Ether-Containing Polyimide Copolymers

    NASA Technical Reports Server (NTRS)

    Fay, Catharine C. (Inventor); St.Clair, Anne K. (Inventor)

    1999-01-01

    Novel polyimide copolymers containing ether linkages were prepared by the reaction of an equimolar amount of dianhydride and a combination of diamines. The polyimide copolymers described herein possess the unique features of low moisture uptake, dimensional stability, good mechanical properties, and moderate glass transition temperatures. These materials have potential application as encapsulants and interlayer dielectrics.

  12. Comparison Of Human Modelling Tools For Efficiency Of Prediction Of EVA Tasks

    NASA Technical Reports Server (NTRS)

    Dischinger, H. Charles, Jr.; Loughead, Tomas E.

    1998-01-01

    Construction of the International Space Station (ISS) will require extensive extravehicular activity (EVA, spacewalks), and estimates of the actual time needed continue to rise. As recently as September, 1996, the amount of time to be spent in EVA was believed to be about 400 hours, excluding spacewalks on the Russian segment. This estimate has recently risen to over 1100 hours, and it could go higher before assembly begins in the summer of 1998. These activities are extremely expensive and hazardous, so any design tools which help assure mission success and improve the efficiency of the astronaut in task completion can pay off in reduced design and EVA costs and increased astronaut safety. The tasks which astronauts can accomplish in EVA are limited by spacesuit mobility. They are therefore relatively simple, from an ergonomic standpoint, requiring gross movements rather than time motor skills. The actual tasks include driving bolts, mating and demating electric and fluid connectors, and actuating levers; the important characteristics to be considered in design improvement include the ability of the astronaut to see and reach the item to be manipulated and the clearance required to accomplish the manipulation. This makes the tasks amenable to simulation in a Computer-Assisted Design (CAD) environment. For EVA, the spacesuited astronaut must have his or her feet attached on a work platform called a foot restraint to obtain a purchase against which work forces may be actuated. An important component of the design is therefore the proper placement of foot restraints.

  13. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021529 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  14. Anderson during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021561 (11 April 2010) --- NASA astronaut Clayton Anderson, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Anderson and Rick Mastracchio (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  15. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021537 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  16. Anderson during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021569 (11 April 2010) --- NASA astronaut Clayton Anderson, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Anderson and Rick Mastracchio (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  17. Anderson during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021562 (11 April 2010) --- NASA astronaut Clayton Anderson, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Anderson and Rick Mastracchio (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  18. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021515 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  19. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021506 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  20. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021503 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  1. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021535 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  2. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021525 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  3. Mastracchio during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021510 (11 April 2010) --- NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Mastracchio and astronaut Clayton Anderson (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  4. Anderson during EVA 2

    NASA Image and Video Library

    2010-04-11

    ISS023-E-021558 (11 April 2010) --- NASA astronaut Clayton Anderson, STS-131 mission specialist, participates in the mission's second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the seven-hour, 26-minute spacewalk, Anderson and Rick Mastracchio (out of frame), mission specialist, unhooked and removed the depleted ammonia tank and installed a 1,700-pound ammonia tank on the station’s Starboard 1 truss, completing the second of a three-spacewalk coolant tank replacement process.

  5. Tani during EVA 14

    NASA Image and Video Library

    2008-01-30

    ISS016-E-026454 (30 Jan. 2008) --- Astronaut Daniel Tani, Expedition 16 flight engineer, participates in a session of extravehicular activity (EVA) as maintenance and construction continue on the International Space Station. During the 7-hour, 10-minute spacewalk, Tani and astronaut Peggy Whitson (out of frame), commander, replaced a motor, known as the Bearing Motor Roll Ring Module (BMRRM), at the base of one of the station's solar wings. The BMRRM is part of the Beta Gimbal Assembly, which experienced electrical failures Dec. 8.

  6. 21 CFR 177.1340 - Ethylene-methyl acrylate copolymer resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-methyl acrylate copolymer resins. 177.1340... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1340 Ethylene-methyl acrylate copolymer resins. Ethylene-methyl acrylate copolymer resins may be safely used as articles or components of...

  7. 40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... *Ethylene-Methacrylic Acid Copolymers *Ethylene-Vinyl Acetate Copolymers *Fatty Acid Resins *Fluorocarbon..., Acrylates (Latex) *PVC Copolymers, Ethylene-Vinyl Chloride *Rosin Derivative Resins *Rosin Modified Resins...

  8. Highly Conductive Anion Exchange Block Copolymers

    DTIC Science & Technology

    We are developing a comprehensive fundamental understanding of the interplay between transport and morphology in newly synthesized hydroxide...conducting block copolymers. We are synthesizing hydroxide conducting block copolymers of various (1) morphology types, (2) ionic concentrations, and (3...ionic domain sizes. We are carefully characterizing the morphology and transport properties using both conventional and new advanced in situ techniques

  9. Study of space shuttle EVA/IVA support requirements. Volume 1: Technical summary report

    NASA Technical Reports Server (NTRS)

    Copeland, R. J.; Wood, P. W., Jr.; Cox, R. L.

    1973-01-01

    Results are summarized which were obtained for equipment requirements for the space shuttle EVA/IVA pressure suit, life support system, mobility aids, vehicle support provisions, and energy 4 support. An initial study of tasks, guidelines, and constraints and a special task on the impact of a 10 psia orbiter cabin atmosphere are included. Supporting studies not related exclusively to any one group of equipment requirements are also summarized. Representative EVA/IVA task scenarios were defined based on an evaluation of missions and payloads. Analysis of the scenarios resulted in a total of 788 EVA/IVA's in the 1979-1990 time frame, for an average of 1.3 per shuttle flight. Duration was estimated to be under 4 hours on 98% of the EVA/IVA's, and distance from the airlock was determined to be 70 feet or less 96% of the time. Payload water vapor sensitivity was estimated to be significant on 9%-17% of the flights. Further analysis of the scenarios was carried out to determine specific equipment characteristics, such as suit cycle and mobility requirements.

  10. Asteroid Redirect Crewed Mission Space Suit and EVA System Maturation

    NASA Technical Reports Server (NTRS)

    Bowie, Jonathan; Buffington, Jesse; Hood, Drew; Kelly, Cody; Naids, Adam; Watson, Richard

    2015-01-01

    The Asteroid Redirect Crewed Mission (ARCM) requires a Launch/Entry/Abort (LEA) suit capability and short duration Extra Vehicular Activity (EVA) capability from the Orion spacecraft. For this mission, the pressure garment selected for both functions is the Modified Advanced Crew Escape Suit (MACES) with EVA enhancements and the life support option that was selected is the Exploration Portable Life Support System (PLSS) currently under development for Advanced Exploration Systems (AES). The proposed architecture meets the ARCM constraints, but much more work is required to determine the details of the suit upgrades, the integration with the PLSS, and the tools and equipment necessary to accomplish the mission. This work has continued over the last year to better define the operations and hardware maturation of these systems. EVA simulations were completed in the Neutral Buoyancy Lab (NBL) and interfacing options were prototyped and analyzed with testing planned for late 2014. This paper discusses the work done over the last year on the MACES enhancements, the use of tools while using the suit, and the integration of the PLSS with the MACES.

  11. pH-sensitive methacrylic copolymers and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2006-02-14

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  12. pH-sensitive methacrylic copolymers and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2007-01-09

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  13. 21 CFR 177.1960 - Vinyl chloride-hexene-1 copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Vinyl chloride-hexene-1 copolymers. 177.1960... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1960 Vinyl chloride-hexene-1 copolymers. The vinyl chloride-hexene-1 copolymers identified in paragraph (a) of this section or as...

  14. Silver-Loaded Cellulose Acetate-g-Poly(ε-caprolactone) Composites

    NASA Astrophysics Data System (ADS)

    Tuburan, CR; Dela Rosa, LE; Reyes, LQ

    2017-06-01

    Cellulose acetate (CA) was grafted with poly(ε-caprolactone) PCL oligomers via the ring-opening of ε-caprolactone (ε-CL) monomer initiated by the hydroxyl functionality of CA. The incorporation of short PCL oligomers in CA’s structure caused the transformation of it crystalline domains into amorphous phases (internal plasticization) as observed by differential scanning calorimetry (DSC). Another evidence of plasticization induced by grafting was the significant reduction of the degradation temperature and stiffness of the copolymers. Proton Nuclear Magnetic Resonance (1H-NMR), Fourier-Transform Infrared (FTIR) Spectroscopies and Gel Permeation Chromatography (GPC) verified success the grafting as suggested by the attachment of PCL on the glucose ring and increase in polymer molecular weights after the reaction. Due to the good films forming ability of the synthesized CA grafted with PCL (CA-g-PCL) material, it was loaded with silver nitrate (AgNO3) and the composite was observed to be have bactericidal against a gram negative bacteria, Escherichia coli, and a gram positive bacteria, Bacillus subtilis.

  15. Tile survey seen during EVA 3

    NASA Image and Video Library

    2005-08-03

    S114-E-6396 (3 August 2005) --- Space Shuttle Discovery’s underside thermal protection tiles are featured in this image photographed by astronaut Stephen K. Robinson, STS-114 mission specialist, during the mission’s third session of extravehicular activities (EVA). Lake Nasser along the Nile River, Egypt is visible near Discovery’s starboard wing.

  16. High-Pressure Oxygen Generation for Outpost EVA Study

    NASA Technical Reports Server (NTRS)

    Jeng, Frank F.; Conger, Bruce; Ewert, Michael K.; Anderson, Molly S.

    2009-01-01

    The amount of oxygen consumption for crew extravehicular activity (EVA) in future lunar exploration missions will be significant. Eight technologies to provide high pressure EVA O2 were investigated. They are: high pressure O2 storage, liquid oxygen (LOX) storage followed by vaporization, scavenging LOX from Lander followed by vaporization, LOX delivery followed by sorption compression, water electrolysis followed by compression, stand-alone high pressure water electrolyzer, Environmental Control and Life Support System (ECLSS) and Power Elements sharing a high pressure water electrolyzer, and ECLSS and In-Situ Resource Utilization (ISRU) Elements sharing a high pressure electrolyzer. A trade analysis was conducted comparing launch mass and equivalent system mass (ESM) of the eight technologies in open and closed ECLSS architectures. Technologies considered appropriate for the two architectures were selected and suggested for development.

  17. Study of EVA operations associated with satellite services

    NASA Technical Reports Server (NTRS)

    Nash, J. O.; Wilde, R. D.

    1982-01-01

    Extravehicular mobility unit (EMU) factors associated with satellite servicing activities are identified and the EMU improvements necessary to enhance satellite servicing operations are outlined. Areas of EMU capabilities, equipment and structural interfaces, time lines, EMU modifications for satellite servicing, environmental hazards, and crew training are vital to manned Eva/satellite services and as such are detailed. Evaluation of EMU capabilities indicates that the EMU can be used in performing near term, basic satellite servicing tasks; however, satellite servicing is greatly enhanced by incorporating key modifications into the EMU. The servicing missions involved in contamination sensitive payload repair are illustrated. EVA procedures and equipment can be standardized, reducing both crew training time and in orbit operations time. By standardizing and coordinating procedures, mission cumulative time lines fall well within the EMU capability.

  18. Commercial Spacewalking: Designing an EVA Qualification Program for Space Tourism

    NASA Technical Reports Server (NTRS)

    Gast, Matthew A.

    2010-01-01

    In the near future, accessibility to space will be opened to anyone with the means and the desire to experience the weightlessness of microgravity, and to look out upon both the curvature of the Earth and the blackness of space, from the protected, shirt-sleeved environment of a commercial spacecraft. Initial forays will be short-duration, suborbital flights, but the experience and expertise of half a century of spaceflight will soon produce commercial vehicles capable of achieving low Earth orbit. Even with the commercial space industry still in its infancy, and manned orbital flight a number of years away, there is little doubt that there will one day be a feasible and viable market for those courageous enough to venture outside the vehicle and into the void, wearing nothing but a spacesuit, armed with nothing but preflight training. What that Extravehicular Activity (EVA) preflight training entails, however, is something that has yet to be defined. A number of significant factors will influence the composition of a commercial EVA training program, but a fundamental question remains: 'what minimum training guidelines must be met to ensure a safe and successful commercial spacewalk?' Utilizing the experience gained through the development of NASA's Skills program - designed to qualify NASA and International Partner astronauts for EVA aboard the International Space Station - this paper identifies the attributes and training objectives essential to the safe conduct of an EVA, and attempts to conceptually design a comprehensive training methodology meant to represent an acceptable qualification standard.

  19. Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes

    NASA Astrophysics Data System (ADS)

    Hoarfrost, Megan Lane

    Incorporating an ionic liquid into one block copolymer microphase provides a platform for combining the outstanding electrochemical properties of ionic liquids with a number of favorable attributes provided by block copolymers. In particular, block copolymers thermodynamically self-assemble into well-ordered nanostructures, which can be engineered to provide a durable mechanical scaffold and template the ionic liquid into continuous ion-conducting nanochannels. Understanding how the addition of an ionic liquid affects the thermodynamic self-assembly of block copolymers, and how the confinement of ionic liquids to block copolymer nanodomains affects their ion-conducting properties is essential for predictable structure-property control. The lyotropic phase behavior of block copolymer/ionic liquid mixtures is shown to be reminiscent of mixtures of block copolymers with selective molecular solvents. A variety of ordered microstructures corresponding to lamellae, hexagonally close-packed cylinders, body-centered cubic, and face-centered cubic oriented micelles are observed in a model system composed of mixtures of imidazolium bis(trifluoromethylsulfonyl)imide ([Im][TFSI]) and poly(styrene- b-2-vinyl pyridine) (PS-b-P2VP). In contrast to block copolymer/molecular solvent mixtures, the interfacial area occupied by each PS-b-P2VP chain decreases upon the addition of [Im][TFSI], indicating a considerable increase in the effective segregation strength of the PS-b-P2VP copolymer with ionic liquid addition. The relationship between membrane structure and ionic conductivity is illuminated through the development of scaling relationships that describe the ionic conductivity of block copolymer/ionic liquid mixtures as a function of membrane composition and temperature. It is shown that the dominant variable influencing conductivity is the overall volume fraction of ionic liquid in the mixture, which means there

  20. Efficient encapsulation of proteins with random copolymers.

    PubMed

    Nguyen, Trung Dac; Qiao, Baofu; Olvera de la Cruz, Monica

    2018-06-12

    Membraneless organelles are aggregates of disordered proteins that form spontaneously to promote specific cellular functions in vivo. The possibility of synthesizing membraneless organelles out of cells will therefore enable fabrication of protein-based materials with functions inherent to biological matter. Since random copolymers contain various compositions and sequences of solvophobic and solvophilic groups, they are expected to function in nonbiological media similarly to a set of disordered proteins in membraneless organelles. Interestingly, the internal environment of these organelles has been noted to behave more like an organic solvent than like water. Therefore, an adsorbed layer of random copolymers that mimics the function of disordered proteins could, in principle, protect and enhance the proteins' enzymatic activity even in organic solvents, which are ideal when the products and/or the reactants have limited solubility in aqueous media. Here, we demonstrate via multiscale simulations that random copolymers efficiently incorporate proteins into different solvents with the potential to optimize their enzymatic activity. We investigate the key factors that govern the ability of random copolymers to encapsulate proteins, including the adsorption energy, copolymer average composition, and solvent selectivity. The adsorbed polymer chains have remarkably similar sequences, indicating that the proteins are able to select certain sequences that best reduce their exposure to the solvent. We also find that the protein surface coverage decreases when the fluctuation in the average distance between the protein adsorption sites increases. The results herein set the stage for computational design of random copolymers for stabilizing and delivering proteins across multiple media.

  1. Changes in the EV-A71 Genome through Recombination and Spontaneous Mutations: Impact on Virulence.

    PubMed

    Mandary, Madiiha Bibi; Poh, Chit Laa

    2018-06-12

    Enterovirus 71 (EV-A71) is a major etiological agent of hand, foot and mouth disease (HFMD) that mainly affects young children less than five years old. The onset of severe HFMD is due to neurological complications bringing about acute flaccid paralysis and pulmonary oedema. In this review, we address how genetic events such as recombination and spontaneous mutations could change the genomic organization of EV-A71, leading to an impact on viral virulence. An understanding of the recombination mechanism of the poliovirus and non-polio enteroviruses will provide further evidence of the emergence of novel strains responsible for fatal HFMD outbreaks. We aim to see if the virulence of EV-A71 is contributed solely by the presence of fatal strains or is due to the co-operation of quasispecies within a viral population. The phenomenon of quasispecies within the poliovirus is discussed to reflect viral fitness, virulence and its implications for EV-A71. Ultimately, this review gives an insight into the evolution patterns of EV-A71 by looking into its recombination history and how spontaneous mutations would affect its virulence.

  2. Behnken during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065720 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  3. Patrick during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065733 (14 Feb. 2010) --- NASA astronaut Nicholas Patrick, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Patrick and Robert Behnken (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  4. Behnken during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065722 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  5. Patrick during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065734 (14 Feb. 2010) --- NASA astronaut Nicholas Patrick, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Patrick and Robert Behnken (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  6. Patrick during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065736 (14 Feb. 2010) --- NASA astronaut Nicholas Patrick, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Patrick and Robert Behnken (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  7. Patrick during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065735 (14 Feb. 2010) --- NASA astronaut Nicholas Patrick, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Patrick and Robert Behnken (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  8. Behnken during EVA 2

    NASA Image and Video Library

    2010-02-14

    S130-E-007858 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission’s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  9. Behnken during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065731 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  10. Behnken during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065750 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  11. Behnken during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065758 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  12. Behnken during EVA 2

    NASA Image and Video Library

    2010-02-14

    S130-E-007862 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission’s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  13. Behnken during EVA-2

    NASA Image and Video Library

    2010-02-14

    ISS022-E-065751 (14 Feb. 2010) --- NASA astronaut Robert Behnken, STS-130 mission specialist, participates in the mission?s second session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the five-hour, 54-minute spacewalk, Behnken and astronaut Nicholas Patrick (out of frame), mission specialist, connected two ammonia coolant loops, installed thermal covers around the ammonia hoses, outfitted the Earth-facing port on the Tranquility node for the relocation of its Cupola, and installed handrails and a vent valve on the new module.

  14. Whitson during EVA 13

    NASA Image and Video Library

    2007-12-18

    ISS016-E-017370 (18 Dec. 2007) --- Astronaut Peggy A. Whitson, Expedition 16 commander, participates in a session of extravehicular activity (EVA). During the 6-hour, 56-minute spacewalk, Whitson and astronaut Daniel Tani (out of frame), flight engineer, looked for the cause of partial loss of electrical power to one of the International Space Station's two Beta Gimbal Assemblies (BGA) for starboard solar wings and examined damage to the starboard Solar Alpha Rotary Joint (SARJ). The spacewalk was the 100th for the construction and maintenance of the station.

  15. Love during EVA 1

    NASA Image and Video Library

    2008-02-11

    S122-E-007850 (11 Feb. 2008) --- Astronaut Stanley Love, STS-122 mission specialist, participates in the first scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the almost eight-hour spacewalk, Love and astronaut Rex Walheim (out of frame), mission specialist, installed a grapple fixture on the Columbus laboratory and prepared electrical and data connections on the module while it rested inside Space Shuttle Atlantis' payload bay. The crewmembers also began work to replace a large nitrogen tank used for pressurizing the station's ammonia cooling system.

  16. Love during EVA 1

    NASA Image and Video Library

    2008-02-11

    S122-E-007853 (11 Feb. 2008) --- Astronaut Stanley Love, STS-122 mission specialist, participates in the first scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the almost eight-hour spacewalk, Love and astronaut Rex Walheim (out of frame), mission specialist, installed a grapple fixture on the Columbus laboratory and prepared electrical and data connections on the module while it rested inside Space Shuttle Atlantis' payload bay. The crewmembers also began work to replace a large nitrogen tank used for pressurizing the station's ammonia cooling system.

  17. Love during EVA 1

    NASA Image and Video Library

    2008-02-11

    S122-E-007771 (11 Feb. 2008) --- Astronaut Stanley Love, STS-122 mission specialist, participates in the first scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the almost eight-hour spacewalk, Love and astronaut Rex Walheim (out of frame), mission specialist, installed a grapple fixture on the Columbus laboratory and prepared electrical and data connections on the module while it rested inside Space Shuttle Atlantis' payload bay. The crewmembers also began work to replace a large nitrogen tank used for pressurizing the station's ammonia cooling system.

  18. Love during EVA 1

    NASA Image and Video Library

    2008-02-11

    S122-E-007794 (11 Feb. 2008) --- Astronaut Stanley Love, STS-122 mission specialist, participates in the first scheduled session of extravehicular activity (EVA) as construction and maintenance continue on the International Space Station. During the almost eight-hour spacewalk, Love and astronaut Rex Walheim (out of frame), mission specialist, installed a grapple fixture on the Columbus laboratory and prepared electrical and data connections on the module while it rested inside Space Shuttle Atlantis' payload bay. The crewmembers also began work to replace a large nitrogen tank used for pressurizing the station's ammonia cooling system.

  19. Tani during EVA 14

    NASA Image and Video Library

    2008-01-30

    ISS016-E-026022 (30 Jan. 2008) --- The face of astronaut Daniel Tani, Expedition 16 flight engineer, is easily recognizable as he participates in a session of extravehicular activity (EVA) as maintenance and construction continue on the International Space Station. During the 7-hour, 10-minute spacewalk, Tani and astronaut Peggy Whitson (out of frame), commander, replaced a motor, known as the Bearing Motor Roll Ring Module (BMRRM), at the base of one of the station's solar wings. The BMRRM is part of the Beta Gimbal Assembly, which experienced electrical failures Dec. 8.

  20. Investigation of the effects of extravehicular activity (EVA) gloves on performance

    NASA Technical Reports Server (NTRS)

    Bishu, Ram R.; Klute, Glenn

    1993-01-01

    The objective was to assess the effects of extravehicular activity (EVA) gloves at different pressures on human hand capabilities. A factorial experiment was performed in which three types of EVA gloves were tested at five pressure differentials. The independent variables tested in this experiment were gender, glove type, pressure differential, and glove make. Six subjects participated in an experiment where a number of dexterity measures, namely time to tie a rope, and the time to assemble a nut and bolt were recorded. Tactility was measured through a two point discrimination test. The results indicate that with EVA gloves strength is reduced by nearly 50 percent, there is a considerable reduction in dexterity, performance decrements increase with increasing pressure differential, and some interesting gender glove interactions were observed, some of which may have been due to the extent (or lack of) fit of the glove to the hand. The implications for the designer are discussed.

  1. Method for making block siloxane copolymers

    DOEpatents

    Butler, Nora; Jessop, Edward S.; Kolb, John R.

    1982-01-01

    A method for synthesizing block polysiloxane copolymers. Diorganoscyclosiloxanes and an end-blocking compound are interacted in the presence of a ring opening polymerization catalyst, producing a blocked prepolymer. The prepolymer is then interacted with a silanediol, resulting in condensation polymerization of the prepolymers. A second end-blocking compound is subsequently introduced to end-cap the polymers and copolymers formed from the condensation polymerization.

  2. Nanopatterned articles produced using reconstructed block copolymer films

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Russell, Thomas P.; Park, Soojin; Wang;, Jia-Yu

    Nanopatterned surfaces are prepared by a method that includes forming a block copolymer film on a substrate, annealing and surface reconstructing the block copolymer film to create an array of cylindrical voids, depositing a metal on the surface-reconstructed block copolymer film, and heating the metal-coated block copolymer film to redistribute at least some of the metal into the cylindrical voids. When very thin metal layers and low heating temperatures are used, metal nanodots can be formed. When thicker metal layers and higher heating temperatures are used, the resulting metal structure includes nanoring-shaped voids. The nanopatterned surfaces can be transferred tomore » the underlying substrates via etching, or used to prepare nanodot- or nanoring-decorated substrate surfaces.« less

  3. Microbial Cometabolism and Polyhydroxyalkanoate Co-polymers.

    PubMed

    Ray, Subhasree; Kalia, Vipin Chandra

    2017-03-01

    Polyhydroxyalkanoate (PHAs) are natural, biodegradable biopolymers, which can be produced from renewable materials. PHAs have potential to replace petroleum derived plastics. Quite a few bacteria can produce PHA under nutritional stress. They generally produce homopolymers of butyrate i.e., polyhydroxybutyrate (PHB), as a storage material. The biochemical characteristics of PHB such as brittleness, low strength, low elasticity, etc. make these unsuitable for commercial applications. Co-polymers of PHA, have high commercial value as they overcome the limitations of PHBs. Co-polymers can be produced by supplementing the feed with volatile fatty acids or through hydrolysates of different biowastes. In this review, we have listed the potential bacterial candidates and the substrates, which can be co-metabolized to produce PHA co-polymers.

  4. Iodinated glycidyl methacrylate copolymer as a radiopaque material for biomedical applications.

    PubMed

    Dawlee, S; Jayabalan, M

    2013-07-01

    Polymeric biomaterial was synthesized by copolymerizing 50:50 mol% of monomers, glycidyl methacrylate and methyl methacrylate. Iodine atoms were then grafted to the epoxide groups of glycidyl methacrylate units, rendering the copolymer radiopaque. The percentage weight of iodine in the present copolymer was found to be as high as 23%. The iodinated copolymer showed higher glass transition temperature and thermal stability in comparison with unmodified polymer. Radiographic analysis showed that the copolymer possessed excellent radiopacity. The iodinated copolymer was cytocompatible to L929 mouse fibroblast cells. The in vivo toxicological evaluation by intracutaneous reactivity test of the copolymer extracts has revealed that the material was nontoxic. Subcutaneous implantation of iodinated copolymer in rats has shown that the material was well tolerated. Upon explantation and histological examination, no hemorrhage, infection or necrosis was observed. The samples were found to be surrounded by a vascularized capsule consisting of connective tissue cells. The results indicate that the iodinated copolymer is biocompatible and may have suitable applications as implantable materials.

  5. Views of EVA performed during STS-6

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Two STS-6 mission specialists busy near the aft bulkhead were photographed with a 70mm camera. Astronauts F. Story Musgrave (at winch device near center) and Donald H. Peterson are setting up winch operations at the aft bulkhead as a simulation for a contingency extravehicular activity (EVA). The orbital maneuvering system (OMS) pods are seen in the background (30211); Musgrave translates down the Challenger's payload bay door hinge line with a bag of latch tools. In the lower left foreground are three canisters containing three getaway special (GAS) experiments. Part of the starboard wing and OMS pod are seen in the background. The gold-foil protected object on the right is the airborne support equipment for the inertial upper stage (IUS) (30212); Peterson (starboard side) and Musgrave evaluate the handrail system on the starboard longeron and aft bulkhead during an EVA. Behind them the vertical stabilizer and OMS pods frame a portion of Mexico's state of Jalisco (30213); Musgrave sus

  6. Controlling block copolymer phase behavior using ionic surfactant

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ray, D.; Aswal, V. K.

    2016-05-23

    The phase behavior of poly(ethylene oxide)-poly(propylene oxide-poly(ethylene oxide) PEO-PPO-PEO triblock copolymer [P85 (EO{sub 26}PO{sub 39}EO{sub 26})] in presence of anionic surfactant sodium dodecyl sulfate (SDS) in aqueous solution as a function of temperature has been studied using dynamic light scattering (DLS) and small-angle neutron scattering (SANS). The measurements have been carried out for fixed concentrations (1 wt%) of block copolymer and surfactants. Each of the individual components (block copolymer and surfactant) and the nanoparticle–surfactant mixed system have been examined at varying temperature. The block copolymer P85 forms spherical micelles at room temperature whereas shows sphere-to-rod like micelle transition at highermore » temperatures. On the other hand, SDS surfactant forms ellipsoidal micelles over a wide temperature range. Interestingly, it is found that phase behavior of mixed micellar system (P85 + SDS) as a function of temperature is drastically different from that of P85, giving the control over the temperature-dependent phase behavior of block copolymers.« less

  7. Morphological studies on block copolymer modified PA 6 blends

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Poindl, M., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de; Bonten, C., E-mail: marcus.poindl@ikt.uni-stuttgart.de, E-mail: christian.bonten@ikt.uni-stuttgart.de

    Recent studies show that compounding polyamide 6 (PA 6) with a PA 6 polyether block copolymers made by reaction injection molding (RIM) or continuous anionic polymerization in a reactive extrusion process (REX) result in blends with high impact strength and high stiffness compared to conventional rubber blends. In this paper, different high impact PA 6 blends were prepared using a twin screw extruder. The different impact modifiers were an ethylene propylene copolymer, a PA PA 6 polyether block copolymer made by reaction injection molding and one made by reactive extrusion. To ensure good particle matrix bonding, the ethylene propylene copolymermore » was grafted with maleic anhydride (EPR-g-MA). Due to the molecular structure of the two block copolymers, a coupling agent was not necessary. The block copolymers are semi-crystalline and partially cross-linked in contrast to commonly used amorphous rubbers which are usually uncured. The combination of different analysis methods like atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) gave a detailed view in the structure of the blends. Due to the partial cross-linking, the particles of the block copolymers in the blends are not spherical like the ones of ethylene propylene copolymer. The differences in molecular structure, miscibility and grafting of the impact modifiers result in different mechanical properties and different blend morphologies.« less

  8. EVA Human Health and Performance Benchmarking Study Overview and Development of a Microgravity Protocol

    NASA Technical Reports Server (NTRS)

    Norcross, Jason; Jarvis, Sarah; Bekdash, Omar; Cupples, Scott; Abercromby, Andrew

    2017-01-01

    The primary objective of this study is to develop a protocol to reliably characterize human health and performance metrics for individuals working inside various EVA suits under realistic spaceflight conditions. Expected results and methodologies developed during this study will provide the baseline benchmarking data and protocols with which future EVA suits and suit configurations (e.g., varied pressure, mass, center of gravity [CG]) and different test subject populations (e.g., deconditioned crewmembers) may be reliably assessed and compared. Results may also be used, in conjunction with subsequent testing, to inform fitness-for-duty standards, as well as design requirements and operations concepts for future EVA suits and other exploration systems.

  9. Arbitrary lattice symmetries via block copolymer nanomeshes

    PubMed Central

    Majewski, Pawel W.; Rahman, Atikur; Black, Charles T.; Yager, Kevin G.

    2015-01-01

    Self-assembly of block copolymers is a powerful motif for spontaneously forming well-defined nanostructures over macroscopic areas. Yet, the inherent energy minimization criteria of self-assembly give rise to a limited library of structures; diblock copolymers naturally form spheres on a cubic lattice, hexagonally packed cylinders and alternating lamellae. Here, we demonstrate multicomponent nanomeshes with any desired lattice symmetry. We exploit photothermal annealing to rapidly order and align block copolymer phases over macroscopic areas, combined with conversion of the self-assembled organic phase into inorganic replicas. Repeated photothermal processing independently aligns successive layers, providing full control of the size, symmetry and composition of the nanoscale unit cell. We construct a variety of symmetries, most of which are not natively formed by block copolymers, including squares, rhombuses, rectangles and triangles. In fact, we demonstrate all possible two-dimensional Bravais lattices. Finally, we elucidate the influence of nanostructure on the electrical and optical properties of nanomeshes. PMID:26100566

  10. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    .../acrylic copolymers are copolymers obtained by reaction of substances permitted by § 177.1010(a) (1), (2... solvent or solvents characterizing the type of food and under the conditions of time and temperature...

  11. Application of EVA guidelines and design criteria. Volume 1: EVA selection/systems design considerations

    NASA Technical Reports Server (NTRS)

    Brown, N. E.

    1973-01-01

    Parameters that require consideration by the planners and designers when planning for man to perform functions outside the vehicle are presented in terms of the impact the extravehicular crewmen and major EV equipment items have on the mission, vehicle, and payload. Summary data on man's performance capabilities in the weightless space environment are also provided. The performance data are based on orbital and transearth EVA from previous space flight programs and earthbound simulations, such as water immersion and zero-g aircraft.

  12. Walheim and Love during EVA 3

    NASA Image and Video Library

    2008-02-15

    S122-E-008750 (15 Feb. 2008) --- Astronaut Rex Walheim (foreground), mission specialist, shares a spacewalk task with astronaut Stanley Love (partially obscured at top of frame), mission specialist. The two astronauts had paired up for the first of three scheduled STS-122 sessions of extravehicular activity earlier in the week and came back out for this final EVA on Feb. 15.

  13. Easy Volcanic Aerosol (EVA v1.0): an idealized forcing generator for climate simulations

    NASA Astrophysics Data System (ADS)

    Toohey, Matthew; Stevens, Bjorn; Schmidt, Hauke; Timmreck, Claudia

    2016-11-01

    Stratospheric sulfate aerosols from volcanic eruptions have a significant impact on the Earth's climate. To include the effects of volcanic eruptions in climate model simulations, the Easy Volcanic Aerosol (EVA) forcing generator provides stratospheric aerosol optical properties as a function of time, latitude, height, and wavelength for a given input list of volcanic eruption attributes. EVA is based on a parameterized three-box model of stratospheric transport and simple scaling relationships used to derive mid-visible (550 nm) aerosol optical depth and aerosol effective radius from stratospheric sulfate mass. Precalculated look-up tables computed from Mie theory are used to produce wavelength-dependent aerosol extinction, single scattering albedo, and scattering asymmetry factor values. The structural form of EVA and the tuning of its parameters are chosen to produce best agreement with the satellite-based reconstruction of stratospheric aerosol properties following the 1991 Pinatubo eruption, and with prior millennial-timescale forcing reconstructions, including the 1815 eruption of Tambora. EVA can be used to produce volcanic forcing for climate models which is based on recent observations and physical understanding but internally self-consistent over any timescale of choice. In addition, EVA is constructed so as to allow for easy modification of different aspects of aerosol properties, in order to be used in model experiments to help advance understanding of what aspects of the volcanic aerosol are important for the climate system.

  14. Method for making block siloxane copolymers

    DOEpatents

    Butler, N.L.; Jessop, E.S.; Kolb, J.R.

    1981-02-25

    A method for synthesizing block polysiloxane copolymers is disclosed. Diorganoscyclosiloxanes and an end-blocking compound are interacted in the presence of a ring opening polymerization catalyst, producing a blocked prepolymer. The prepolymer is then interacted with a silanediol, resulting in condensation polymerization of the prepolymers. A second end-blocking compound is subsequently introduced to end-cap the polymers and copolymers formed from the condensation polymerization.

  15. Tribological Behavior of Aqueous Copolymer Lubricant in Mixed Lubrication Regime.

    PubMed

    Ta, Thi D; Tieu, A Kiet; Zhu, Hongtao; Zhu, Qiang; Kosasih, Prabouno B; Zhang, Jie; Deng, Guanyu

    2016-03-02

    Although a number of experiments have been attempted to investigate the lubrication of aqueous copolymer lubricant, which is applied widely in metalworking operations, a comprehensive theoretical investigation at atomistic level is still lacking. This study addresses the influence of loading pressure and copolymer concentration on the structural properties and tribological performance of aqueous copolymer solution of poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) (PPO-PEO-PPO) at mixed lubrication using a molecular dynamic (MD) simulation. An effective interfacial potential, which has been derived from density functional theory (DFT) calculations, was employed for the interactions between the fluid's molecules and iron surface. The simulation results have indicated that the triblock copolymer is physisorption on iron surface. Under confinement by iron surfaces, the copolymer molecules form lamellar structure in aqueous solution and behave differently from its bulk state. The lubrication performance of aqueous copolymer lubricant increases with concentration, but the friction reduction is insignificant at high loading pressure. Additionally, the plastic deformation of asperity is dependent on both copolymer concentration and loading pressure, and the wear behavior shows a linear dependence of friction force on the number of transferred atoms between contacting asperities.

  16. Polyamide copolymers having 2,5-furan dicarboxamide units

    DOEpatents

    Chisholm, Bret Ja; Samanta, Satyabrata

    2017-09-19

    Polyamide copolymers, and methods of making and using polyamide copolymers, having 2,5-furan dicarboxamide units are disclosed herein. Such polymers can be useful for engineering thermoplastics having advantageous physical and/or chemical properties.

  17. HPMA copolymers: Origins, early developments, present, and future☆

    PubMed Central

    Kopeček, Jindřich; Kopečková, Pavla

    2010-01-01

    The overview covers the discovery of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers, initial studies on their synthesis, evaluation of biological properties, and explorations of their potential as carriers of biologically active compounds in general and anticancer drugs in particular. The focus is on the research in the authors’ laboratory – the development of macromolecular therapeutics for the treatment of cancer and musculoskeletal diseases. In addition, the evaluation of HPMA (co)polymers as building blocks of mod and new biomaterials is presented: the utilization of semitelechelic poly(HPMA) and HPMA copolymers for the modification of biomaterial and protein surfaces and the design of hybrid block and graft HPMA copolymers that self-assemble into smart hydrogels. Finally, suggestions for the design of second-generation macromolecular therapeutics are portrayed. PMID:19919846

  18. Dynamic photoinduced realignment processes in photoresponsive block copolymer films: effects of the chain length and block copolymer architecture.

    PubMed

    Sano, Masami; Shan, Feng; Hara, Mitsuo; Nagano, Shusaku; Shinohara, Yuya; Amemiya, Yoshiyuki; Seki, Takahiro

    2015-08-07

    A series of block copolymers composed of an amorphous poly(butyl methacrylate) (PBMA) block connected with an azobenzene (Az)-containing liquid crystalline (PAz) block were synthesized by changing the chain length and polymer architecture. With these block copolymer films, the dynamic realignment process of microphase separated (MPS) cylinder arrays of PBMA in the PAz matrix induced by irradiation with linearly polarized light was studied by UV-visible absorption spectroscopy, and time-resolved grazing incidence small angle X-ray scattering (GI-SAXS) measurements using a synchrotron beam. Unexpectedly, the change in the chain length hardly affected the realignment rate. In contrast, the architecture of the AB-type diblock or the ABA-type triblock essentially altered the realignment feature. The strongly cooperative motion with an induction period before realignment was characteristic only for the diblock copolymer series, and the LPL-induced alignment change immediately started for triblock copolymers and the PAz homopolymer. Additionally, a marked acceleration in the photoinduced dynamic motions was unveiled in comparison with a thermal randomization process.

  19. The acetate switch.

    PubMed

    Wolfe, Alan J

    2005-03-01

    To succeed, many cells must alternate between life-styles that permit rapid growth in the presence of abundant nutrients and ones that enhance survival in the absence of those nutrients. One such change in life-style, the "acetate switch," occurs as cells deplete their environment of acetate-producing carbon sources and begin to rely on their ability to scavenge for acetate. This review explains why, when, and how cells excrete or dissimilate acetate. The central components of the "switch" (phosphotransacetylase [PTA], acetate kinase [ACK], and AMP-forming acetyl coenzyme A synthetase [AMP-ACS]) and the behavior of cells that lack these components are introduced. Acetyl phosphate (acetyl approximately P), the high-energy intermediate of acetate dissimilation, is discussed, and conditions that influence its intracellular concentration are described. Evidence is provided that acetyl approximately P influences cellular processes from organelle biogenesis to cell cycle regulation and from biofilm development to pathogenesis. The merits of each mechanism proposed to explain the interaction of acetyl approximately P with two-component signal transduction pathways are addressed. A short list of enzymes that generate acetyl approximately P by PTA-ACKA-independent mechanisms is introduced and discussed briefly. Attention is then directed to the mechanisms used by cells to "flip the switch," the induction and activation of the acetate-scavenging AMP-ACS. First, evidence is presented that nucleoid proteins orchestrate a progression of distinct nucleoprotein complexes to ensure proper transcription of its gene. Next, the way in which cells regulate AMP-ACS activity through reversible acetylation is described. Finally, the "acetate switch" as it exists in selected eubacteria, archaea, and eukaryotes, including humans, is described.

  20. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may be...

  1. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may be...

  2. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may be...

  3. 21 CFR 177.1020 - Acrylonitrile/butadiene/sty-rene co-polymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acrylonitrile/butadiene/sty-rene co-polymer. 177... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances.../butadiene/sty-rene co-polymer. Acrylonitrile/butadiene/styrene copolymer identified in this section may be...

  4. Fabrication routes for one-dimensional nanostructures via block copolymers

    NASA Astrophysics Data System (ADS)

    Tharmavaram, Maithri; Rawtani, Deepak; Pandey, Gaurav

    2017-05-01

    Nanotechnology is the field which deals with fabrication of materials with dimensions in the nanometer range by manipulating atoms and molecules. Various synthesis routes exist for the one, two and three dimensional nanostructures. Recent advancements in nanotechnology have enabled the usage of block copolymers for the synthesis of such nanostructures. Block copolymers are versatile polymers with unique properties and come in many types and shapes. Their properties are highly dependent on the blocks of the copolymers, thus allowing easy tunability of its properties. This review briefly focusses on the use of block copolymers for synthesizing one-dimensional nanostructures especially nanowires, nanorods, nanoribbons and nanofibers. Template based, lithographic, and solution based approaches are common approaches in the synthesis of nanowires, nanorods, nanoribbons, and nanofibers. Synthesis of metal, metal oxides, metal oxalates, polymer, and graphene one dimensional nanostructures using block copolymers have been discussed as well.

  5. View of Astronaut Bruc McCandless during EVA

    NASA Image and Video Library

    1984-02-11

    S84-27023 (7 Feb 1984) --- This 70mm frame shows astronaut Bruce McCandless II moving in to conduct a test involving the Trunion Pin Attachment Device (TPAD) he carries and the Shuttle Pallet Satellite (SPAS-01A) partially visible at bottom of frame. SPAS was a stand-in for the damaged Solar Maximum Satellite (SMS) which will be visited for repairs by the STS-41C Shuttle crew in early spring. This particular Extravehicular Activity (EVA) session was a rehearsal for the SMS visit. The test and the actual visit to the SMS both involve the use of jet-powered, hand-controlled Manned Maneuvering Unit (MMU). The one McCandless uses is the second unit to be tested on this flight. Astronaut Robert L. Stewart got a chance to work with both MMU's on the two EVA's.

  6. The economic value added (EVA) resulting from medical care of functional amblyopia, strabismus, (pathologies of binocular vision) and asthma.

    PubMed

    Beauchamp, Cynthia L; Felius, Joost; Beauchamp, George R

    2010-01-01

    Value analysis in health care calculates the economic value added (EVA) that results from improvements in health and health care. Our purpose was to develop an EVA model and to apply the model to typical and hypothetical (instantaneous and perfect) cures for amblyopia, surgical strabismus and asthma, as another, but non-ophthalmological disease standard for comparison, in the United States. The model is based on changes in utility and longevity, the associated incremental costs, and an estimate of the value of life. Univariate sensitivity analyses were performed to arrive at a plausible range of outcomes. For the United States, the EVA for current practice amblyopia care is 12.9B dollars (billion) per year, corresponding to a return on investment (ROI) of 10.4% per yr. With substantial increases in investment aimed at maximal improvement ("perfect cure"), the EVA is 32.7B per yr, with ROI of 5.3% per yr. The EVA for typical surgical strabismus care is 10.3B per yr. A perfect cure may yield EVA of 9.6B per yr. The EVA for asthma is 1317B per yr (ROI 20.4% per yr.., while a perfect cure may yield EVA of 110 B per yr. Sensitivity analysis demonstrated the relatively large effects of incidence, utility, and longevity, while incremental costs have a relatively minor effect on the EVA. The economic value added by improvements in patient-centered outcomes is very large. Failing to make the necessary investments in research, prevention, detection, prompt treatment and rehabilitation of these diseases, at virtually any conceivable cost, appears economically, medically, morally and ethically deficient and consequently wasteful at very least economically for our society.

  7. Preparations for Underwater EVA training for the STS 41-G crew

    NASA Image and Video Library

    1984-07-05

    S84-36900 (29 June 1984) ---Astronauts Robert L. Crippen (right) and Jon A. McBride, crew commander and pilot, respectively, for NASA's 41-G Space Shuttle mission, don self contained underwater breathing apparatus (SCUBA) gear prior to their underwater to observe a simulation of an extravehicular activity (EVA) to be performed on their mission. Astronauts Kathryn D. Sullivan and David C. Leestma, two of three mission specialists on the seven-member crew, are scheduled for the EVA. The underwater training took place in the Johnson Space Center's weightless environment training facility (WET-F).

  8. EVA Development and Verification Testing at NASA's Neutral Buoyancy Laboratory

    NASA Technical Reports Server (NTRS)

    Jairala, Juniper C.; Durkin, Robert; Marak, Ralph J.; Sipila, Stepahnie A.; Ney, Zane A.; Parazynski, Scott E.; Thomason, Arthur H.

    2012-01-01

    As an early step in the preparation for future Extravehicular Activities (EVAs), astronauts perform neutral buoyancy testing to develop and verify EVA hardware and operations. Neutral buoyancy demonstrations at NASA Johnson Space Center's Sonny Carter Training Facility to date have primarily evaluated assembly and maintenance tasks associated with several elements of the International Space Station (ISS). With the retirement of the Shuttle, completion of ISS assembly, and introduction of commercial players for human transportation to space, evaluations at the Neutral Buoyancy Laboratory (NBL) will take on a new focus. Test objectives are selected for their criticality, lack of previous testing, or design changes that justify retesting. Assembly tasks investigated are performed using procedures developed by the flight hardware providers and the Mission Operations Directorate (MOD). Orbital Replacement Unit (ORU) maintenance tasks are performed using a more systematic set of procedures, EVA Concept of Operations for the International Space Station (JSC-33408), also developed by the MOD. This paper describes the requirements and process for performing a neutral buoyancy test, including typical hardware and support equipment requirements, personnel and administrative resource requirements, examples of ISS systems and operations that are evaluated, and typical operational objectives that are evaluated.

  9. Self-assembly of block copolymers on topographically patterned polymeric substrates

    DOEpatents

    Russell, Thomas P.; Park, Soojin; Lee, Dong Hyun; Xu, Ting

    2016-05-10

    Highly-ordered block copolymer films are prepared by a method that includes forming a polymeric replica of a topographically patterned crystalline surface, forming a block copolymer film on the topographically patterned surface of the polymeric replica, and annealing the block copolymer film. The resulting structures can be used in a variety of different applications, including the fabrication of high density data storage media. The ability to use flexible polymers to form the polymeric replica facilitates industrial-scale processes utilizing the highly-ordered block copolymer films.

  10. Poly(ortho-phenylenediamine-co-aniline) based copolymer with improved capacitance

    NASA Astrophysics Data System (ADS)

    Olmedo-Martínez, Jorge L.; Farías-Mancilla, Bárbara I.; Vega-Rios, Alejandro; Zaragoza-Contreras, E. Armando

    2017-10-01

    A poly(ortho-phenylenediamine-co-aniline) copolymer is synthesized via the oxidative route, using a 1:1 M ratio of aniline to ortho-phenylenediamine (oPDA) and ammonium persulfate as the oxidizing agent. Infrared spectroscopy indicates that the copolymer contains the functional groups typically present in polyaniline and poly(ortho-phenylenediamine); whereas UV-vis-NIR spectroscopy shows that the copolymer adopts a phenazine-type structure. Cyclic voltammetry evidences the copolymer synthesis, as a redox peak at -65 mV, different from those exhibited by polyaniline (160 mV and 600 mV) or poly(o-phenylenediamine) (-240 mV) is observed. Finally, electrochemical impedance spectroscopy and the charge/discharge test provide support to propose the copolymer application in electrodes for supercapacitors.

  11. MS Grunsfeld and Linnehan on middeck after EVA 1

    NASA Image and Video Library

    2002-03-04

    STS109-349-027 (4 March 2002) --- Astronauts John M. Grunsfeld and Richard M. Linnehan, STS-109 payload commander and mission specialist, respectively, wearing the liquid cooling and ventilation garment that complements the Extravehicular Mobility Unit (EMU) space suit, are photographed on the mid deck of the Space Shuttle Columbia after the mission’s first session of extravehicular activity (EVA). The EVA-1 team replaced one of the telescope’s two second-generation solar arrays, which is also known as SA2, and a Diode Box Assembly. The solar array was replaced with a new, third-generation solar array, which is called SA3. The space walkers also did some prep work for STS-109’s other space walks.

  12. Design and simulation of EVA tools for first servicing mission of HST

    NASA Technical Reports Server (NTRS)

    Naik, Dipak; Dehoff, P. H.

    1993-01-01

    The Hubble Space Telescope (HST) was launched into near-earth orbit by the space shuttle Discovery on April 24, 1990. The payload of two cameras, two spectrographs, and a high-speed photometer is supplemented by three fine-guidance sensors that can be used for astronomy as well as for star tracking. A widely reported spherical aberration in the primary mirror causes HST to produce images of much lower quality than intended. A space shuttle repair mission in late 1993 will install small corrective mirrors that will restore the full intended optical capability of the HST. The first servicing mission (FSM) will involve considerable extravehicular activity (EVA). It is proposed to design special EVA tools for the FSM. This report includes details of the data acquisition system being developed to test the performance of the various EVA tools in ambient as well as simulated space environment.

  13. Modern analytics for synthetically derived complex drug substances: NMR, AFFF-MALS, and MS tests for glatiramer acetate.

    PubMed

    Rogstad, Sarah; Pang, Eric; Sommers, Cynthia; Hu, Meng; Jiang, Xiaohui; Keire, David A; Boyne, Michael T

    2015-11-01

    Glatiramer acetate (GA) is a mixture of synthetic copolymers consisting of four amino acids (glutamic acid, lysine, alanine, and tyrosine) with a labeled molecular weight range of 5000 to 9000 Da. GA is marketed as Copaxone™ by Teva for the treatment of multiple sclerosis. Here, the agency has evaluated the structure and composition of GA and a commercially available comparator, Copolymer-1. Modern analytical technologies which can characterize these complex mixtures are desirable for analysis of their comparability and structural "sameness." In the studies herein, a molecular fingerprinting approach is taken using mass-accurate mass spectrometry (MS) analysis, nuclear magnetic resonance (NMR) (1D-(1)H-NMR, 1D-(13)C-NMR, and 2D NMR), and asymmetric field flow fractionation (AFFF) coupled with multi-angle light scattering (MALS) for an in-depth characterization of three lots of the marketplace drug and a formulated sample of the comparator. Statistical analyses were applied to the MS and AFFF-MALS data to assess these methods' ability to detect analytical differences in the mixtures. The combination of multiple orthogonal measurements by liquid chromatography coupled with MS (LC-MS), AFFF-MALS, and NMR on the same sample set was found to be fit for the intended purpose of distinguishing analytical differences between these complex mixtures of peptide chains.

  14. Mission control activity during STS-61 EVA-1

    NASA Image and Video Library

    1993-12-05

    Joseph Fanelli, at the Integrated Communications Officer console, monitors the televised activity of Astronauts Story Musgrave and Jeffrey A. Hoffman. The vetern astronauts were performing the first extravehicular activity (EVA-1) of the STS-61 Hubble Space Telescope (HST) servicing mission.

  15. 21 CFR 177.1570 - Poly-1-butene resins and butene/ethylene copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Poly-1-butene resins and butene/ethylene copolymers... resins and butene/ethylene copolymers. The poly-1-butene resins and butene/ethylene copolymers identified... the catalytic polymerization of 1-butene liquid monomer. Butene/ethylene copolymers are produced by...

  16. Communication: Molecular-level insights into asymmetric triblock copolymers: Network and phase development

    NASA Astrophysics Data System (ADS)

    Tallury, Syamal S.; Mineart, Kenneth P.; Woloszczuk, Sebastian; Williams, David N.; Thompson, Russell B.; Pasquinelli, Melissa A.; Banaszak, Michal; Spontak, Richard J.

    2014-09-01

    Molecularly asymmetric triblock copolymers progressively grown from a parent diblock copolymer can be used to elucidate the phase and property transformation from diblock to network-forming triblock copolymer. In this study, we use several theoretical formalisms and simulation methods to examine the molecular-level characteristics accompanying this transformation, and show that reported macroscopic-level transitions correspond to the onset of an equilibrium network. Midblock conformational fractions and copolymer morphologies are provided as functions of copolymer composition and temperature.

  17. Co-polymer Films for Sensors

    NASA Technical Reports Server (NTRS)

    Ryan, Margaret A. (Inventor); Jewell, April D. (Inventor); Taylor, Charles (Inventor); Yen, Shiao-Pin S. (Inventor); Kisor, Adam (Inventor); Manatt, Kenneth S. (Inventor); Blanco, Mario (Inventor); Goddard, William A. (Inventor); Homer, Margie L. (Inventor); Shevade, Abhijit V. (Inventor)

    2012-01-01

    Embodiments include a sensor comprising a co-polymer, the co-polymer comprising a first monomer and a second monomer. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is polystyrene and the second monomer is poly-2-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium benzylamine chloride. Other embodiments are described and claimed.

  18. Co-polymer films for sensors

    NASA Technical Reports Server (NTRS)

    Ryan, Margaret A. (Inventor); Homer, Margie L. (Inventor); Yen, Shiao-Pin S. (Inventor); Kisor, Adam (Inventor); Jewell, April D. (Inventor); Shevade, Abhijit V. (Inventor); Manatt, Kenneth S. (Inventor); Taylor, Charles (Inventor); Blanco, Mario (Inventor); Goddard, William A. (Inventor)

    2010-01-01

    Embodiments include a sensor comprising a co-polymer, the co-polymer comprising a first monomer and a second monomer. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is polystyrene and the second monomer is poly-2-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium benzylamine chloride. Other embodiments are described and claimed.

  19. Development and Characterization of Poly(1-vinylpyrrolidone-co-vinyl acetate) Copolymer Based Polymer Electrolytes

    PubMed Central

    Sa'adun, Nurul Nadiah; Subramaniam, Ramesh; Kasi, Ramesh

    2014-01-01

    Gel polymer electrolytes (GPEs) are developed using poly(1-vinylpyrrolidone-co-vinyl acetate) [P(VP-co-VAc)] as the host polymer, lithium bis(trifluoromethane) sulfonimide [LiTFSI] as the lithium salt and ionic liquid, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [EMImTFSI] by using solution casting technique. The effect of ionic liquid on ionic conductivity is studied and the optimum ionic conductivity at room temperature is found to be 2.14 × 10−6 S cm−1 for sample containing 25 wt% of EMImTFSI. The temperature dependence of ionic conductivity from 303 K to 353 K exhibits Arrhenius plot behaviour. The thermal stability of the polymer electrolyte system is studied by using thermogravimetric analysis (TGA) while the structural and morphological properties of the polymer electrolyte is studied by using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction analysis (XRD), respectively. PMID:25431781

  20. Whitson during EVA 13

    NASA Image and Video Library

    2007-12-18

    ISS016-E-017499 (18 Dec. 2007) --- Astronaut Peggy A. Whitson, Expedition 16 commander, participates in a session of extravehicular activity (EVA). During the 6-hour, 56-minute spacewalk, Whitson and astronaut Daniel Tani (out of frame), flight engineer, looked for the cause of partial loss of electrical power to one of the International Space Station's two Beta Gimbal Assemblies (BGA) for starboard solar wings and examined damage to the starboard Solar Alpha Rotary Joint (SARJ). The spacewalk was the 100th for the construction and maintenance of the station. A blue and white Earth provides the background for the scene.