Suppressing lossy-film-induced angular mismatches between reflectance and transmittance extrema: optimum optical designs of interlayers and AR coating for maximum transmittance into active layers of CIGS solar cells.

PubMed

Chang, Yin-Jung

2014-01-13

The investigation of optimum optical designs of interlayers and antireflection (AR) coating for achieving maximum average transmittance (T(ave)) into the CuIn(1-x)Ga(x)Se2 (CIGS) absorber of a typical CIGS solar cell through the suppression of lossy-film-induced angular mismatches is described. Simulated-annealing algorithm incorporated with rigorous electromagnetic transmission-line network approach is applied with criteria of minimum average reflectance (R(ave)) from the cell surface or maximum T(ave) into the CIGS absorber. In the presence of one MgF2 coating, difference in R(ave) associated with optimum designs based upon the two distinct criteria is only 0.3% under broadband and nearly omnidirectional incidence; however, their corresponding T(ave) values could be up to 14.34% apart. Significant T(ave) improvements associated with the maximum-T(ave)-based design are found mainly in the mid to longer wavelengths and are attributed to the largest suppression of lossy-film-induced angular mismatches over the entire CIGS absorption spectrum. Maximum-T(ave)-based designs with a MgF2 coating optimized under extreme deficiency of angular information is shown, as opposed to their minimum-R(ave)-based counterparts, to be highly robust to omnidirectional incidence.

Development of a new low cost antireflective coating technique for solar cells

NASA Technical Reports Server (NTRS)

Wohlgemuth, J. H.; Warfield, D. B.; Johnson, G. A.

1982-01-01

The goal of this study was the development of an antireflective (AR) coating technique that has the potential for high throughput and low cost yet is capable of producing films of good optical quality. Previous efforts to develop sprayed AR coatings had utilized titanium isopropoxide mixed with volatile solvents. These films worked well on smooth surfaces but when applied to etched semi-crystalline silicon surfaces yielded inconsistent results with more than 20 percent of the AM1 incident light being reflected. In this program titanium isopropoxide was sprayed directly onto heater wafers (410 C) to produce a uniform AR coating even on highly textured surfaces. Tests on various types of solar cells yielded performance improvements for the hot sprayed AR cells that are equivalent to that observed for evaporated TiOx AR coated cells. As an extension of this effort a new double layer AR consisting of a bottom layer of hot sprayed titanium isopropoxide and a top layer of hot sprayed aluminum isopropoxide in methylene chloride has resulted in more than 10 percent improvement in cell output as compared to a single layer AR cell.

CW laser damage testing of RAR nano-textured fused silica and YAG

NASA Astrophysics Data System (ADS)

MacLeod, Bruce D.; Hobbs, Douglas S.; Manni, Anthony D.; Sabatino, Ernest; Bernot, David M.; DeFrances, Sage; Randi, Joseph A.; Thomas, Jeffrey

2017-11-01

A study of the continuous wave (CW) laser induced damage threshold (LiDT) of fused silica and yttrium aluminum garnet (YAG) optics was conducted to further illustrate the enhanced survivability within high power laser systems of an anti-reflection (AR) treatment consisting of randomly distributed surface relief nanostructures (RAR). A series of three CW LiDT tests using the 1070nm wavelength, 16 KW fiber laser test bed at Penn State Electro-Optic Center (PSEOC) were designed and completed, with improvements in the testing protocol, areal coverage, and maximum exposure intensities implemented between test cycles. Initial results for accumulated power, stationary site exposures of RAR nano-textured optics showed no damage and low surface temperatures similar to the control optics with no AR treatment. In contrast, optics with thin-film AR coatings showed high surface temperatures consistent with absorption by the film layers. Surface discriminating absorption measurements made using the Photothermal Common-path Interferometry (PCI) method, showed zero added surface absorption for the RAR nanotextured optics, and absorption levels in the 2-5 part per million range for thin-film AR coated optics. In addition, the surface absorption of thin-film AR coatings was also found to have localized absorption spikes that are likely pre-cursors for damage. Subsequent CW LiDT testing protocol included raster scanning an increased intensity focused beam over the test optic surface where it was found that thin-film AR coated optics damaged at intensities in the 2 to 5 MW/cm2 range with surface temperatures over 250C during the long-duration exposures. Significantly, none of the 10 RAR nano-textured fused silica optics tested could be damaged up to the maximum system intensity of 15.5 MW/cm2, and surface temperatures remained low. YAG optics tested during the final cycle exhibited a similar result with RAR nano-textured surfaces surviving intensities over 3 times higher than thin-film AR coated surfaces. This result was correlated with PCI measurements that also show zero-added surface absorption for the RAR nano-textured YAG optics.

Alizarin Red S-Confined Layer-By-Layer Films as Redox-Active Coatings on Electrodes for the Voltammetric Determination of L-Dopa

PubMed Central

Takahashi, Shigehiro; Suzuki, Iwao; Sugawara, Tatsuro; Seno, Masaru; Minaki, Daichi; Anzai, Jun-Ichi

2017-01-01

The preparation of redox-active coatings is a key step in fabricating electrochemical biosensors. To this goal, a variety of coating materials have been used in combination with redox-active compounds. In this study, alizarin red S (ARS) was confined in layer-by-layer (LbL) films composed of poly(ethyleneimine) (PEI) and carboxymethylcellulose (CMC) to study the redox properties. A gold (Au) disc electrode coated with PEI/CMC LbL film was immersed in an ARS solution to uptake ARS into the film. ARS was successfully confined in the LbL film through electrostatic interactions. The cyclic voltammogram (CV) of ARS-confined PEI/CMC film-coated electrodes thus prepared exhibited redox waves in the potential range from −0.5 to −0.7 V originating from 9,10-anthraquinone moiety in ARS, demonstrating that ARS preserves its redox activity in the LbL film. An additional oxidation peak appeared around −0.4 V in the CV recorded in the solution containing phenylboronic acid (PBA), due to the formation of a boronate ester of ARS (ARS-PBA) in the film. The oxidation peak current at −0.4 V decreased upon addition of 3,4-dihydroxyphenylalanine (L-dopa) to the solution. Thus, the results suggest a potential use of the ARS-confined PEI/CMC films for constructing voltammetric sensors for L-dopa. PMID:28772942

Front surface passivation of silicon solar cells with antireflection coating

NASA Technical Reports Server (NTRS)

Crotty, G.; Daud, T.; Kachare, R.

1987-01-01

It is demonstrated that the deposition and postdeposition sintering of an antireflection (AR) coating in hydrogen acts to passivate silicon solar cells. Cells with and without an SiO2 passivating layer, coated with a TiO(x)/Al2O3 AR coating, showed comparable enhancements in short-wavelength spectral response and in open-circuit voltage Voc after sintering at 400 C for 5 min in a hydrogen ambient. The improvement in Voc of cells without SiO2 is attributed to front-surface passivation by the AR coating during processing.

Voltammetric Response of Alizarin Red S-Confined Film-Coated Electrodes to Diol and Polyol Compounds: Use of Phenylboronic Acid-Modified Poly(ethyleneimine) as Film Component.

PubMed

Takahashi, Shigehiro; Suzuki, Iwao; Ojima, Takuto; Minaki, Daichi; Anzai, Jun-Ichi

2018-01-22

Alizarin red S (ARS) was confined in layer-by-layer (LbL) films composed of phenylboronic acid-modified poly(ethyleneimine) (PBA-PEI) and carboxymethylcellulose (CMC) to study the voltammetric response to diol and polyol compounds. The LbL film-coated gold (Au) electrode and quartz slide were immersed in an ARS solution to uptake ARS into the film. UV-visible absorption spectra of ARS-confined LbL film suggested that ARS formed boronate ester (ARS-PBS) in the film. The cyclic voltammetry of the ARS-confined LbL film-coated electrodes exhibited oxidation peaks at -0.50 and -0.62 V, which were ascribed to the oxidation reactions of ARS-PBS and free ARS, respectively, in the LbL film. The peak current at -0.62 V increased upon the addition of diol or polyol compounds such as L-dopa, glucose, and sorbitol into the solution, depending on the concentration, whereas the peak current at -0.50 V decreased. The results suggest a possible use of ARS-confined PBA-PEI/CMC LbL film-coated Au electrodes for the construction of voltammetric sensors for diol and polyol compounds.

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

Li, Xiaoyu; Graduate University of Chinese Academy of Sciences, Beijing 100049; He, Junhui, E-mail: jhhe@mail.ipc.ac.cn

Graphical abstract: High performance broadband antireflective and water-repellent coatings were fabricated on glass substrates, which can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. - Highlights: • Broadband anti-reflective and water-repellent coatings were fabricated. • Transmittance increased to 99.0%, significantly higher than that of commercial solar glasses. • The performance of standard solar cells with the AR coating was enhanced as much as 6.6%. - Abstract: High performance broadband antireflective (AR) and water-repellent coatings were fabricated on glass substrates by assembly of silica nanoparticles and polyelectrolytes via the layer-by-layermore » (LbL) assembly technique, followed by calcination and hydrophobic modification. A porous poly(diallyladimethylammonium chloride) (PDDA)/20 nm SiO{sub 2} nanoparticles (S-20) multilayer coating with AR property was prepared first. The maximum transmittance is as high as 99.0%, while that of the glass substrate is only 91.3%. After calcination and hydrophobic modification, the coating became water-repellent while maintaining the good AR property. Such water-repellent AR coatings can improve the short-circuit current of solar cells as much as 6.6% in comparison with glass substrates without the coatings. Scanning electron microscopy (SEM) was used to observe the morphology and thickness of coatings. Transmission spectra and reflection spectra were characterized by UV–vis spectrophotometer. The surface wettability was studied by a contact angle/interface system.« less

Characterization of Silicon Moth-Eye Antireflection Coatings for Astronomical Applications in the Infrared

NASA Astrophysics Data System (ADS)

Jeram, Sarik; Ge, Jian; Jiang, Peng; Phillips, Blayne

2016-01-01

Silicon moth-eye antireflective structures have emerged to be an excellent approachfor reducing the amount of light that is lost upon incidence on a given surface of optics made of silicon. This property has been exploited for a wide variety of products ranging from eyeglasses and flat-panel displays to solar panels. These materials typically come in the form of coatings that are applied to an optical substrate such as glass. Moth-eye coatings, made of a periodic array of subwavelength pillars on silicon substrates or other substrates, can produce the desired antireflection (AR) performance for a broad wavelength range and over a wide range of incident angles. In the field of astronomy, every photon striking a detector is significant - and thus, losses from reflectivity at the various optical interfaces before a detector can have significant implications to the science at hand. Moth-eye AR coatings on these optical interfaces may minimize their reflection losses while maximizing light throughput for a multitude of different astronomical instruments. In addition, moth-eye AR coatings, which are patterned directly on silicon surfaces, can significantly enhance the coating durability. At the University of Florida, we tested two moth-eye filters designed for use in the near-infrared regime at 1-8 microns by examining their optical properties, such as transmission, the scattered light, and wavefront quality, and testing the coatings at cryogenic temperatures to characterize their viability for use in both ground- and space-based infrared instruments. This presentation will report our lab evaluation results.

Voltammetric Response of Alizarin Red S-Confined Film-Coated Electrodes to Diol and Polyol Compounds: Use of Phenylboronic Acid-Modified Poly(ethyleneimine) as Film Component

PubMed Central

Takahashi, Shigehiro; Suzuki, Iwao; Ojima, Takuto; Minaki, Daichi

2018-01-01

Alizarin red S (ARS) was confined in layer-by-layer (LbL) films composed of phenylboronic acid-modified poly(ethyleneimine) (PBA-PEI) and carboxymethylcellulose (CMC) to study the voltammetric response to diol and polyol compounds. The LbL film-coated gold (Au) electrode and quartz slide were immersed in an ARS solution to uptake ARS into the film. UV-visible absorption spectra of ARS-confined LbL film suggested that ARS formed boronate ester (ARS-PBS) in the film. The cyclic voltammetry of the ARS-confined LbL film-coated electrodes exhibited oxidation peaks at −0.50 and −0.62 V, which were ascribed to the oxidation reactions of ARS-PBS and free ARS, respectively, in the LbL film. The peak current at −0.62 V increased upon the addition of diol or polyol compounds such as L-dopa, glucose, and sorbitol into the solution, depending on the concentration, whereas the peak current at −0.50 V decreased. The results suggest a possible use of ARS-confined PBA-PEI/CMC LbL film-coated Au electrodes for the construction of voltammetric sensors for diol and polyol compounds. PMID:29361775

Link between mechanical strength and laser damage threshold for antireflective coating made by sol-gel

NASA Astrophysics Data System (ADS)

Avice, J.; Piombini, H.; Boscher, C.; Belleville, P.; Vaudel, G.; Brotons, G.; Ruello, P.; Gusev, V.

2017-11-01

The MegaJoule Laser (LMJ) for inertial confinement fusion experiments is currently in operation at CEA-CESTA in France. All the lenses are coated by an antireflective (AR) layer to optimize the light power transmission. This AR layer is manufactured by sol-gel process, a soft chemical process, associated with a liquid phase coating technique to realize thin film of metal oxide. These optical components are hardened into ammoniac vapors in order to mechanically reinforce the AR coating and to make them more handling. This hardening induces a thickness reduction of the layer so an increase of the stiffness and sometimes a crazing of the layer. As these optical components undergo a high-power laser beam, so, it is important to verify if the AR properties (optical and mechanical) influence the value of the threshold laser damage. A series of coated samples have been manufactured having variable elastic moduli to discuss this point. In that purpose, a homemade Laser Induced Damage Threshold (LIDT) setup has been developed to test the layers under laser flux. We describe the used methods and different results are given. Preliminary results obtained on several coated samples with variable elastic moduli are presented. We show that whatever are the elastic stiffness of the AR coating, an overall decrease of the threshold appears with no noticeable effect of the mechanical properties of the AR coatings. Some possible explanations are given.

Low cost sol-gel derived SiC-SiO2 nanocomposite as anti reflection layer for enhanced performance of crystalline silicon solar cells

NASA Astrophysics Data System (ADS)

Jannat, Azmira; Lee, Woojin; Akhtar, M. Shaheer; Li, Zhen Yu; Yang, O.-Bong

2016-04-01

This paper describes the preparation, characterizations and the antireflection (AR) coating application in crystalline silicon solar cells of sol-gel derived SiC-SiO2 nanocomposite. The prepared SiC-SiO2 nanocomposite was effectively applied as AR layer on p-type Si-wafer via two step processes, where the sol-gel of precursor solution was first coated on p-type Si-wafer using spin coating at 2000 rpm and then subjected to annealing at 450 °C for 1 h. The crystalline, and structural observations revealed the existence of SiC and SiO2 phases, which noticeably confirmed the formation of SiC-SiO2 nanocomposite. The SiC-SiO2 layer on Si solar cells was found to be an excellent AR coating, exhibiting the low reflectance of 7.08% at wavelengths ranging from 400 to 1000 nm. The fabricated crystalline Si solar cell with SiC-SiO2 nanocomposite AR coating showed comparable power conversion efficiency of 16.99% to the conventional SixNx AR coated Si solar cell. New and effective sol-gel derived SiC-SiO2 AR layer would offer a promising technique to produce high performance Si solar cells with low-cost.

Next-generation all-silica coatings for UV applications

NASA Astrophysics Data System (ADS)

Melninkaitis, A.; Grinevičiūtė, L.; Abromavičius, G.; Mažulė, L.; Smalakys, L.; Pupka, E.; Š čiuka, M.; Buzelis, R.; Kičas, S.

2017-11-01

Band-gap and refractive index are known as fundamental properties determining intrinsic optical resistance of multilayer dielectric coatings. By considering this fact we propose novel approach to manufacturing of interference thin films, based on artificial nano-structures of modulated porosity embedded in high band-gap matrix. Next generation all-silica mirrors were prepared by GLancing Angle Deposition (GLAD) using electron beam evaporation. High reflectivity (HR) was achieved by tailoring the porosity of highly resistant silica material during the thin film deposition process. Furthermore, the proposed approach was also demonstrated to work well in case of anti-reflection (AR) coatings. Conventional HR HfO2 and SiO2 as well as AR Al2O3 and SiO2 multilayers produced by Ion Beam Sputtering (IBS) were used as reference coatings. Damage performance of experimental coatings was also analyzed. All-silica based GLAD approach resulted in significant improvement of intrinsic laser damage resistance properties if compared to conventional coatings. Besides laser damage testing, other characteristics of experimental coatings are analyzed and discussed - reflectance, surface roughness and optical scattering. We believe that reported concept can be expanded to virtually any design of thin film coatings thus opening a new way of next generation highly resistant thin films well suited for high power and UV laser applications.

Design of a three-layer antireflection coating for high efficiency indium phosphide solar cells using a chemical oxide as first layer

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

Moulot, J.; Faur, M.; Faur, M.

1995-10-01

It is well known that the behavior of III-V compound based solar cells is largely controlled by their surface, since the majority of light generated carriers (63% for GaAs and 79% for InP) are created within 0.2 mu m of the surface of the illuminated cell. Consequently, the always observed high surface recombination velocity (SRV) on these cells is a serious limiting factor for their high efficiency performance, especially for those with p-n junction made by either thermal diffusion or ion implantation. A good surface passivation layer, ideally a grown oxide as opposed to a deposited one, will cause amore » significant reduction in the SRV without adding interface problems, thus improving the performance of III-V compound based solar cells. Another significant benefit to the overall performance of the solar cells can be achieved by a substantial reduction of their large surface optical reflection by the use of a well designed antireflection (AR) coating. In this paper, the authors demonstrate the effectiveness of using a chemically grown thermally and chemically stable oxide, not only for surface passivation but also as an integral part of a 3-layer AR coating for thermally diffused p+n InP solar cells. A phosphorus-rich interfacial oxide, In(PO3)3, is grown at the surface of the p+ emitter using an etchant based on HNO3, o-H3PO4 and H2O2. This oxide has the unique properties of passivating the surface as well as serving as an efficient antireflective layer yielding a measured record high AMO open-circuit voltage of 890.3 mV on a thermally diffused InP(Cd,S) solar cell. Unlike conventional single layer AR coatings such as ZnS, Sb2O3, SiO or double layer AR coatings such as ZnS/MgF2 deposited by e-beam or resistive evaporation, this oxide preserves the stoichiometry of the InP surface.« less

Concept Study of Optical Configurations for High-Frequency Telescope for LiteBIRD

NASA Astrophysics Data System (ADS)

Hasebe, T.; Kashima, S.; Ade, P. A. R.; Akiba, Y.; Alonso, D.; Arnold, K.; Aumont, J.; Baccigalupi, C.; Barron, D.; Basak, S.; Beckman, S.; Borrill, J.; Boulanger, F.; Bucher, M.; Calabrese, E.; Chinone, Y.; Cho, H.-M.; Cukierman, A.; Curtis, D. W.; de Haan, T.; Dobbs, M.; Dominjon, A.; Dotani, T.; Duband, L.; Ducout, A.; Dunkley, J.; Duval, J. M.; Elleflot, T.; Eriksen, H. K.; Errard, J.; Fischer, J.; Fujino, T.; Funaki, T.; Fuskeland, U.; Ganga, K.; Goeckner-Wald, N.; Grain, J.; Halverson, N. W.; Hamada, T.; Hasegawa, M.; Hattori, K.; Hattori, M.; Hayes, L.; Hazumi, M.; Hidehira, N.; Hill, C. A.; Hilton, G.; Hubmayr, J.; Ichiki, K.; Iida, T.; Imada, H.; Inoue, M.; Inoue, Y.; Irwin, K. D.; Ishino, H.; Jeong, O.; Kanai, H.; Kaneko, D.; Katayama, N.; Kawasaki, T.; Kernasovskiy, S. A.; Keskitalo, R.; Kibayashi, A.; Kida, Y.; Kimura, K.; Kisner, T.; Kohri, K.; Komatsu, E.; Komatsu, K.; Kuo, C. L.; Kurinsky, N. A.; Kusaka, A.; Lazarian, A.; Lee, A. T.; Li, D.; Linder, E.; Maffei, B.; Mangilli, A.; Maki, M.; Matsumura, T.; Matsuura, S.; Meilhan, D.; Mima, S.; Minami, Y.; Mitsuda, K.; Montier, L.; Nagai, M.; Nagasaki, T.; Nagata, R.; Nakajima, M.; Nakamura, S.; Namikawa, T.; Naruse, M.; Nishino, H.; Nitta, T.; Noguchi, T.; Ogawa, H.; Oguri, S.; Okada, N.; Okamoto, A.; Okamura, T.; Otani, C.; Patanchon, G.; Pisano, G.; Rebeiz, G.; Remazeilles, M.; Richards, P. L.; Sakai, S.; Sakurai, Y.; Sato, Y.; Sato, N.; Sawada, M.; Segawa, Y.; Sekimoto, Y.; Seljak, U.; Sherwin, B. D.; Shimizu, T.; Shinozaki, K.; Stompor, R.; Sugai, H.; Sugita, H.; Suzuki, A.; Suzuki, J.; Tajima, O.; Takada, S.; Takaku, R.; Takakura, S.; Takatori, S.; Tanabe, D.; Taylor, E.; Thompson, K. L.; Thorne, B.; Tomaru, T.; Tomida, T.; Tomita, N.; Tristram, M.; Tucker, C.; Turin, P.; Tsujimoto, M.; Uozumi, S.; Utsunomiya, S.; Uzawa, Y.; Vansyngel, F.; Wehus, I. K.; Westbrook, B.; Willer, M.; Whitehorn, N.; Yamada, Y.; Yamamoto, R.; Yamasaki, N.; Yamashita, T.; Yoshida, M.

2018-05-01

The high-frequency telescope for LiteBIRD is designed with refractive and reflective optics. In order to improve sensitivity, this paper suggests the new optical configurations of the HFT which have approximately 7 times larger focal planes than that of the original design. The sensitivities of both the designs are compared, and the requirement of anti-reflection (AR) coating on the lens for the refractive option is derived. We also present the simulation result of a sub-wavelength AR structure on both surfaces of silicon, which shows a band-averaged reflection of 1.1-3.2% at 101-448 GHz.

Integrated Glass Coating Manufacturing Line

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

Brophy, Brenor

2015-09-30

This project aims to enable US module manufacturers to coat glass with Enki’s state of the art tunable functionalized AR coatings at the lowest possible cost and highest possible performance by encapsulating Enki’s coating process in an integrated tool that facilitates effective process improvement through metrology and data analysis for greater quality and performance while reducing footprint, operating and capital costs. The Phase 1 objective was a fully designed manufacturing line, including fully specified equipment ready for issue of purchase requisitions; a detailed economic justification based on market prices at the end of Phase 1 and projected manufacturing costs andmore » a detailed deployment plan for the equipment.« less

Novel Passivating/Antireflective Coatings for Space Solar Cells

NASA Technical Reports Server (NTRS)

Faur, Mircea; Faur, Maria; Bailey, S. G.; Flood, D. J.; Faur, H. M.; Mateescu, C. G.; Alterovitz, S. A.; Scheiman, D.; Jenkins, P. P.; Brinker, D. J.

2005-01-01

We are developing a novel process to grow passivating/antireflective (AR) coatings for terrestrial and space solar cells. Our approach involves a Room Temperature Wet Chemical Growth (RTWCG) process, which was pioneered, and is under development at SPECMAT, Inc., under a Reimbursable Space Act Agreement with NASA Glenn Research Center. The RTWCG passivating/AR coatings with graded index of refraction are applied in one easy step on finished (bare) cells. The RTWCG coatings grown on planar, textured and porous Si, as well as on poly-Si, CuInSe2, and III-V substrates, show excellent uniformity irrespective of surface topography, crystal orientation, size and shape. In this paper we present some preliminary results of the RTWCG coatings on Si and III-V substrates that show very good potential for use as a passivation/AR coating for space solar cell applications. Compared to coatings grown using conventional techniques, the RTWCG coatings have the potential to reduce reflection losses and improve current collection near the illuminated surface of space solar cells, while reducing the fabrication costs.

Ion Assisted Deposition of Optical Coatings.

DTIC Science & Technology

1986-08-01

dielectric films. They repo- ted ion-induced phase transitions and reductions in optical scatter for bombarded films. In this research program, the film...SiO 2 AR coating (20X). 7 7 145 4A I 10 wun Figure VI-6. Micrograph of fluorine damaged AIJO /SiO 2 AR coating (20X); different site than in Figure

Challenges and solutions for high performance SWIR lens design

NASA Astrophysics Data System (ADS)

Gardner, M. C.; Rogers, P. J.; Wilde, M. F.; Cook, T.; Shipton, A.

2016-10-01

Shortwave infrared (SWIR) cameras are becoming increasingly attractive due to the improving size, resolution and decreasing prices of InGaAs focal plane arrays (FPAs). The rapid development of competitively priced HD performance SWIR cameras has not been matched in SWIR imaging lenses with the result that the lens is now more likely to be the limiting factor in imaging quality than the FPA. Adapting existing lens designs from the visible region by re-coating for SWIR will improve total transmission but diminished image quality metrics such as MTF, and in particular large field angle performance such as vignetting, field curvature and distortion are serious consequences. To meet this challenge original SWIR solutions are presented including a wide field of view fixed focal length lens for commercial machine vision (CMV) and a wide angle, small, lightweight defence lens and their relevant design considerations discussed. Issues restricting suitable glass types will be examined. The index and dispersion properties at SWIR wavelengths can differ significantly from their visible values resulting in unusual glass combinations when matching doublet elements. Materials chosen simultaneously allow athermalization of the design as well as containing matched CTEs in the elements of doublets. Recently, thinned backside-illuminated InGaAs devices have made Vis.SWIR cameras viable. The SWIR band is sufficiently close to the visible that the same constituent materials can be used for AR coatings covering both bands. Keeping the lens short and mass low can easily result in high incidence angles which in turn complicates coating design, especially when extended beyond SWIR into the visible band. This paper also explores the potential performance of wideband Vis.SWIR AR coatings.

Aerocoat 7 Replacement Coatings

NASA Technical Reports Server (NTRS)

2008-01-01

Kennedy Space Center has used Aerocoat 7 (AR-7) to protect stainless-steel flex hoses at Launch Complex (LC-39) and hydraulic lines of the Mobile Launcher Platform (MLP) because it provides excellent corrosion protection in low-temperature applications. The Sovereign Company produced AR-7 exclusively for NASA but discontinued production because the coating released high levels of volatile organic compounds (VOCs) and had a significant environmental impact. The purpose of this project was to select and evaluate potential replacement coatings for AR-7 that would be more environmentally sound. The physical and mechanical properties of commercially available coatings were investigated through the Internet. The ideal coating would be fluid enough to penetrate the outer mesh of a stainless-steel flex hose and coat the inner hose, and flexible enough to withstand the movement of the hose, as well as the expansion and contraction of its metal caused by changes in temperature.

Development of Multispectral Sandwich-Type IR Windows.

DTIC Science & Technology

1977-04-01

Coatings 52 4.4 Thermophyslcal Properties 59 4.5 Mechanical Properties 62 4.5.1 Hardness and Strength of Window Components ... 62 4.5.2 Bond...AR coating ) 51 36 Transmittance vs. wavelength for a 0.050 in. thick CVD ZnS plate (No AR coating ) 53 37 Transmittance of a ZnS/ZnSe composite...compared to 67% calculated for the ZnSe window alone. As described below, anti -reflection coatings deposited onto the composite window will further enhance

Radiation Stability of Triple Coatings Based on Transition-Metal Nitrides Under Irradiation By Alpha Particles and Argon Ions

NASA Astrophysics Data System (ADS)

Potekaev, A. I.; Kislitsyn, S. B.; Uglov, V. V.; Klopotov, A. A.; Gorlachev, I. D.; Klopotov, V. D.; Grinkevich, L. S.

2016-05-01

The data on the influence of irradiation of (Ti, Cr)N1-x coatings by helium and argon ions on their surface structure are presented. The (Ti, Cr)N1-x coatings 50-300 nm in thickness were formed on carbon steel substrates by vacuum-arc deposition. Irradiation of the coated specimens was performed in a DC-60 heavy-ion accelerator by low-energy 4He+1, 4He+2 and 40Ar5+ ions and high-energy 40Ar5+ ions up to the fluence 1.0·1017 ion/cm2 at the irradiation temperature not higher than 150°C. It is shown that irradiation of the (Ti, Cr)N1-x coating surface by 4He+1, 4He+2 and 40Ar5+ ions with the energy 20 keV/charge does not give rise to any noticeable structural changes nor any surface blistering, while its irradiation by 40Ar5+ ions with the energy 1.50 MeV/amu causes blistering.

Ion-plating of solar cell arrays encapsulation task: LSA project 32

NASA Technical Reports Server (NTRS)

Volkers, J. C.

1983-01-01

An ion plating process by which solar cells can be metallized and AR coated, yielding efficiencies equal to or better than state-of-the-art cells, was developed. It was demonstrated that ion plated AR films may be used as an effective encapsulant, offering primary protection for the metallization. It was also shown that ion plated metallization and AR coatings can be consistent with the project cost goals.

Synthesis of antireflective silica coatings through the synergy of polypeptide layer-by-layer assemblies and biomineralization

NASA Astrophysics Data System (ADS)

Lee, Yung-Lun; Lin, Ting-Xuan; Hsu, Feng-Ming; Jan, Jeng-Shiung

2016-01-01

We report a versatile approach to synthesize silica coatings with antireflective (AR) characteristics through the combination of a layer-by-layer (LbL) assembly technique and biomineralization. LbL assembled decanoyl-modified poly(l-lysine)/poly(l-glutamic acid) (PLL-g-Dec/PLGA) multilayer films were used as templates for silica mineralization, followed by calcination. The specific deposition of silica onto the LbL polypeptide assemblies through amine-catalyzed polycondensation resulted in silica coatings that exhibited the transcription of the nano-/microstructured polypeptide films and their film thickness and porosity can be tuned by varying the number of bilayers, degree of substitution, and PLL molecular weight. AR silica coatings exhibiting more than 6% increase in transmittance in the near UV/visible spectral range can be obtained at an optimized refractive index, thickness, and surface roughness. The abrasion test showed that the silica coatings exhibited sufficient structural durability due to continuous silica nanostructures and low surface roughness. This study demonstrated that nanostructured thin films can be synthesized for AR coatings using the synergy between the LbL assembly technique and biomineralization.We report a versatile approach to synthesize silica coatings with antireflective (AR) characteristics through the combination of a layer-by-layer (LbL) assembly technique and biomineralization. LbL assembled decanoyl-modified poly(l-lysine)/poly(l-glutamic acid) (PLL-g-Dec/PLGA) multilayer films were used as templates for silica mineralization, followed by calcination. The specific deposition of silica onto the LbL polypeptide assemblies through amine-catalyzed polycondensation resulted in silica coatings that exhibited the transcription of the nano-/microstructured polypeptide films and their film thickness and porosity can be tuned by varying the number of bilayers, degree of substitution, and PLL molecular weight. AR silica coatings exhibiting more than 6% increase in transmittance in the near UV/visible spectral range can be obtained at an optimized refractive index, thickness, and surface roughness. The abrasion test showed that the silica coatings exhibited sufficient structural durability due to continuous silica nanostructures and low surface roughness. This study demonstrated that nanostructured thin films can be synthesized for AR coatings using the synergy between the LbL assembly technique and biomineralization. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06948c

Laser damage threshold measurements of microstructure-based high reflectors

NASA Astrophysics Data System (ADS)

Hobbs, Douglas S.

2008-10-01

In 2007, the pulsed laser induced damage threshold (LIDT) of anti-reflecting (AR) microstructures built in fused silica and glass was shown to be up to three times greater than the LIDT of single-layer thin-film AR coatings, and at least five times greater than multiple-layer thin-film AR coatings. This result suggested that microstructure-based wavelength selective mirrors might also exhibit high LIDT. Efficient light reflection over a narrow spectral range can be produced by an array of sub-wavelength sized surface relief microstructures built in a waveguide configuration. Such surface structure resonant (SSR) filters typically achieve a reflectivity exceeding 99% over a 1-10nm range about the filter center wavelength, making SSR filters useful as laser high reflectors (HR). SSR laser mirrors consist of microstructures that are first etched in the surface of fused silica and borosilicate glass windows and subsequently coated with a thin layer of a non-absorbing high refractive index dielectric material such as tantalum pent-oxide or zinc sulfide. Results of an initial investigation into the LIDT of single layer SSR laser mirrors operating at 532nm, 1064nm and 1573nm are described along with data from SEM analysis of the microstructures, and spectral reflection measurements. None of the twelve samples tested exhibited damage thresholds above 3 J/cm2 when illuminated at the resonant wavelength, indicating that the simple single layer, first order design will need further development to be suitable for high power laser applications. Samples of SSR high reflectors entered in the Thin Film Damage Competition also exhibited low damage thresholds of less than 1 J/cm2 for the ZnS coated SSR, and just over 4 J/cm2 for the Ta2O5 coated SSR.

Iron deposition as acidic groundwater encounters carbonates in the alluvium of Pinal Creek, Arizona, U.S.A.

USGS Publications Warehouse

Lind, Carol J.; Oscarson, R.L.

1997-01-01

In a column experiment, acidic groundwater from Pinal Creek Arizona, a Cu mining area, was eluted through a composited alluvial sample obtained from a core that had been removed from a well downgradient of the acidic groundwater. The minerals present in typical grains and flakes in the alluvium before and after the elution were determined by X-ray diffraction (XRD), scanning electron microscopy, and energy dispersive multichannel analyses (EDX). The concentrations of Fe, Ti, Mn, Si, Al, Na, Ca, K, Mg and S in these grains and flakes and in their microcrystalline surface coatings were measured by EDX. In addition to magnetite, hematite, and Fe-Ti oxides, Fe was most concentrated in micas (especially biotite-like flakes) and in the microcrystalline coatings. The measured elements in these microcrystalline coatings were primarily K, Fe, Al, and Si. The microcrystalline coatings on the mica flakes also contained Mg. The approximate 1:3 Mg:Si atomic ratios (ARs) of the biotite-like flakes both before and after the elution would suggest that the Fe deposited during the elution had not substituted for Mg in these flakes. As a result of the elution, assuming no loss of Si, the averaged recorded Fe:Si AR of the microcrystalline coatings increased from (0,46 to 0.58):3.00. Iron deposition on the typical grains and flakes may relate to the presence of Fe in the particle on which it is deposited or to the presence of Fe in the microcrystalline surface coatings before elution. The data here are not sufficient for a statistical evaluation, but elution caused the following trends: (1) The Fe:Si A R increased in the (K,Fe,Al,Si)-microcrystalline surface coatings; (2) For the mica flakes, there was more than a 2-fold increase in the Fe:Si AR for the microcrystalline surface coatings of the Fe-rich biotite-like flakes but no measurable increase of the Fe:Si AR for the microcrystalline surface coatings of the muscovite-like flakes that contained 3-5 times less Fe; (3) Also for the biotite-like flakes, the increase in Fe:Si AR was greater in the flakes that had a higher Fe:Si AR; (4) The Fe deposition on the Fe-rich microcrystalline surface coatings of the feldspar was much greater than on the Fe-poor, beige quartz and feldspar grains that, prior to elution, had only CaSO4 microcrystalline coatings; and (5) No Fe was deposited on Fe-poor grains with no microcrystalline surface coating.

Preparation and stress evolution of sol–gel SiO{sub 2} antireflective coatings for small-size anisotropic lithium triborate crystals

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

Tian, Bingtao; Wang, Xiaodong, E-mail: xiaodong-wang@tongji.edu.cn; Niu, Yanyan

2016-04-15

Lithium triborate (LiB{sub 3}O{sub 5}, LBO) crystal is now one of the most useful nonlinear optical materials for frequency conversion of high power lasers. The use of the crystal, however, has been hampered by the unavailability of antireflective (AR) coatings with high laser damage resistance. In this work, a “point contact” dip-coating method is developed to prepare sol–gel SiO{sub 2} AR coatings on small-size LBO crystals. Using this approach, we obtain a homogenous coating surface on an 8 mm×8 mm×3 mm LBO crystal. The stress measurements show that the stresses in sol–gel SiO{sub 2} coatings vary with the time ofmore » natural drying, which is beyond our expectation. The anisotropic Young’s modulus of the LBO crystal and the different evolution tendency of the stress in the different SiO{sub 2} coating layers are found to be responsible for the crack of the double-layer AR coatings on anisotropic LBO crystal. Meanwhile, the resulting coatings on LBO crystal achieve a LIDT of over 15 J/cm{sup 2} (532 nm, 3ns) and the coated LBO is expected to have a transmittance of over 99% at 800 nm.« less

Space qualification of IR-reflecting coverslides for GaAs solar cells

NASA Technical Reports Server (NTRS)

Meulenberg, Andrew

1995-01-01

Improvements to GaAs solar array performance, from the use on solar cell coverslides of several reflecting coatings that reject unusable portions of the solar spectrum, are quantified. Blue-red-rejection (BRR) coverslides provide both infrared reflection (IRR) and ultraviolet rejection (UVR). BRR coverslides were compared to conventional antireflection (AR) and ultraviolet (UV) coated coverslides. A 2% improvement in peak-power output, relative to that from Ar-coated coverslides, is seen for cells utilizing BRR coverslides with the widest bandpass. Coverslide BRR-filter bandpass width and covered-solar-cell short-circuit current is a function of incident light angle and the observed narrower-bandpass filters are more sensitive to change in angle from the normal than are wide-bandpass filters. The first long-term (3000 hours) UV testing of unirradiated and 1 MeV electron-irradiated GaAs solar cells, with multilayer-coated coverslides to reduce solar array operating temperature, has indicated that all multilayer coatings on coverslides and solar cells will experience degradation from the space environment (UV and/or electrons). Five types of coverslide coatings, designed for GaAs solar cells, were tested as part of a NASA-sponsored space-flight qualification for BRR, multi-layer-coated, coverslides. The reponse to the different radiations varied with the coatings. The extent of degradation and its consequences on the solar cell electrical characteristics depend upon the coatings and the radiation. In some cases, an improved optical coupling was observed during long-term UV exposure to the optical stack. The benefits of multi-layered solar cell optics may depend upon both the duration and the radiation environment of a mission.

Experimental Tests of UltraFlex Array Designs in Low Earth Orbital and Geosynchronous Charging Environments

NASA Technical Reports Server (NTRS)

Galofaro, Joel T.; Vayner, Boris V.; Hillard, Grover B.

2011-01-01

The present ground based investigations give the first definitive look describing the expected on-orbit charging behavior of Orion UltraFlex array coupons in the Low Earth Orbital and Geosynchronous Environments. Furthermore, it is important to note that the LEO charging environment also applies to the International Space Station as well as to the lunar mission charging environments. The GEO charging environment includes the bounding case for all lunar orbital and lunar surface mission environments. The UltraFlex thin film photovoltaic array technology has been targeted to become the sole power system for life support and on-orbit power for the manned Aires Crew Exploration Vehicle. It is therefore, crucial to gain an understanding of the complex charging behavior to answer some of the basic performance and survivability issues in an attempt to ascertain that a single UltraFlex array design will be able to cope with the projected worst case LEO and GEO charging environments. Testing was limited to four array coupons, two coupons each from two different array manufactures, Emcore and Spectrolab. The layout of each array design is identical and varies only in the actual cell technology used. The individual array cells from each manufacturer have an antireflection layered coating and come in two different varieties either uncoated (only AR coating) or coated with a thin conducting ITO layer. The LEO Plasma tests revealed that all four coupons passed the arc threshold -120 V bias tests. GEO electron gun charging tests revealed that only front side area of ITO coated coupons passed tests. Only the Emcore AR array passed backside Stage 2 GEO Tests.

Bacteriomimetic poly-γ-glutamic acid surface coating for hemocompatibility and safety of nanomaterials.

PubMed

Shim, Gayong; Kim, Dongyoon; Kim, Jinyoung; Suh, Min Sung; Kim, Youn Kyu; Oh, Yu-Kyoung

2017-08-01

Poly-γ-glutamic acid (PGA), a major component of the bacterial capsule, is known to confer hydrophilicity to bacterial surfaces and protect bacteria from interactions with blood cells. We tested whether applying a bacteriomimetic surface coating of PGA modulates interactions of nanomaterials with blood cells or affects their safety and photothermal antitumor efficacy. Amphiphilic PGA (APGA), prepared by grafting phenylalanine residues to PGA, was used to anchor PGA to reduced graphene oxide (rGO) nanosheets, a model of hydrophobic nanomaterials. Surface coating of rGO with bacterial capsule-like APGA yielded APGA-tethered rGO nanosheets (ArGO). ArGO nanosheets remained stable in serum over 4 weeks, whereas rGO in plain form precipitated in serum within 5 minutes. Moreover, ArGO did not interact with blood cells, whereas rGO in plain form or as a physical mixture with PGA formed aggregates with blood cells. Mice administered ArGO at a dose of 50 mg/kg showed 100% survival and no hepatic or renal toxicity. No mice survived exposure at the same dose of rGO or a PGA/rGO mixture. Following intravenous administration, ArGO showed a greater distribution to tumors and prolonged tumor retention compared with other nanosheet formulations. Irradiation with near-infrared light completely ablated tumors in mice treated with ArGO. Our results indicate that a bacteriomimetic surface modification of nanomaterials with bacterial capsule-like APGA improves the stability in blood, biocompatibility, tumor distribution, and photothermal antitumor efficacy of rGO. Although APGA was used here to coat the surfaces of rGO, it could be applicable to coat surfaces of other hydrophobic nanomaterials.

Manufacturing and coating of optical components for the EnMAP hyperspectral imager

NASA Astrophysics Data System (ADS)

Schürmann, M.; Gäbler, D.; Schlegel, R.; Schwinde, S.; Peschel, T.; Damm, C.; Jende, R.; Kinast, J.; Müller, S.; Beier, M.; Risse, S.; Sang, B.; Glier, M.; Bittner, H.; Erhard, M.

2016-07-01

The optical system of the hyperspectral imager of the Environmental Mapping and Analysis Program (EnMAP) consists of a three-mirror anastigmat (TMA) and two independent spectrometers working in the VNIR and SWIR spectral range, respectively. The VNIR spectrometer includes a spherical NiP coated Al6061 mirror that has been ultra-precisely diamond turned and finally coated with protected silver as well as four curved fused silica (FS) and flint glass (SF6) prisms, respectively, each with broadband antireflection (AR) coating, while the backs of the two outer prisms are coated with a high-reflective coating. For AR coating, plasma ion assisted deposition (PIAD) has been used; the high-reflective enhanced Ag-coating on the backside has been deposited by magnetron sputtering. The SWIR spectrometer contains four plane and spherical gold-coated mirrors, respectively, and two curved FS prisms with a broadband antireflection coating. Details about the ultra-precise manufacturing of metal mirrors and prisms as well as their coating are presented in this work.

Development of improved lithium tantalate pyroelectric detectors

NASA Technical Reports Server (NTRS)

Byer, N. E.; Vanderjagt, A.; Holton, W.

1978-01-01

A program was undertaken to increase the detectivity of LiTaO3 pyroelectric detectors to meet a performance requirement of D star (500 K, 15 Hz)=4x10 to the 9th power cm Hz1/2W-1. Emphasis was placed on reduction of the thermal conductance of the detector element to its surroundings, thinning the detector wafer to a thickness less than 3 micrometers, and increasing the absorptivity of the standard metallic film coatings. During the program, thermal conductance was reduced 41 percent through the use of reticulated (slotted) structures. Self-supported detector wafers less than 2 micrometers thick were fabricated. Multiple layer coatings, including an AR coating, with 16 percent more absorptance, were designed and fabricated. Later refinements in the multilayer design program have absorptivities of 75-80 percent, but detectors with these coatings had to be more than 2 micrometers thick because of a mismatch in the thermal expansion coefficients with LiTaO3.

The thickness correction of sol-gel coating using ion-beam etching in the preparation of antireflection coating

NASA Astrophysics Data System (ADS)

Dong, Siyu; Xie, Lingyun; He, Tao; Jiao, Hongfei; Bao, Ganghua; Zhang, Jinlong; Wang, Zhanshan; Cheng, Xinbin

2017-09-01

For the sol-gel method, it is still challenging to achieve excellent spectral performance when preparing antireflection (AR) coating by this way. The difficulty lies in controlling the film thickness accurately. To correct the thickness error of sol-gel coating, a hybrid approach that combined conventional sol-gel process with ion-beam etching technology was proposed in this work. The etching rate was carefully adjusted and calibrated to a relatively low value for removing the redundant material. Using atomic force microscope (AFM), it has been demonstrated that film surface morphology will not be changed in this process. After correcting the thickness error, an AR coating working at 1064 nm was prepared with transmittance higher than 99.5%.

Optical characterization of antirelaxation coatings

NASA Astrophysics Data System (ADS)

Tsvetkov, S.; Gateva, S.; Cartaleva, S.; Mariotti, E.; Nasyrov, K.

2018-03-01

Antirelaxation coatings (ARC) are used in optical cells containing alkali metal vapor to reduce the depolarization of alkali atoms after collisions with the cell walls. The long-lived ground state polarization is a basis for development of atomic clocks, magnetometers, quantum memory, slow light experiments, precision measurements of fundamental symmetries etc. In this work, a simple method for measuring the number of collisions of the alkali atoms with the cell walls without atomic spin randomization (Nasyrov et al., Proc. SPIE (2015)) was applied to characterize the AR properties of two PDMS coatings prepared from different solutions in ether (PDMS 2% and PDMS 5%). We observed influence of the light-induced atomic desorption (LIAD) on the AR properties of coatings.

Wear and Tribological Properties of Silicon-Containing Diamond-Like Carbon (Si-DLC) Coatings Synthesized with Nitrogen, Argon Plus Nitrogen, and Argon Ion Beams

DTIC Science & Technology

1998-06-01

of the (Ar + N)/Si-DLC and Ar/Si-DLC coatings. Meletis, Erdemir, and Fenske [10, 11] have attributed the smaller friction coefficient of their...vol. 15, p. 227,1986. 9. Rao, P., and E. H. Lee. /. of Mater. Sei., vol. 10, p. 2661,1996. 10. Meletis, E. I., A. Erdemir, and G. R. Fenske . Surface

Investigation of Al Coated Mg for Biomedical Applications

NASA Astrophysics Data System (ADS)

Elmrabet, Nabila; Roe, Martin; Neate, Nigel; Grant, David M.; Brown, Paul D.

The corrosion resistant properties of 1-2 μm thick Al coatings deposited by radio frequency magnetron sputtering on polished Mg surfaces, within Ar and Ar/H2 environments, have been appraised. The coatings were heat-treated at 300°C for 5 h to induce the formation of bioinert Al2O3, and samples were corroded within phosphate buffered saline solution at 37°C to mimic the biological environment. Both the as-deposited and heat-treated coatings were found to delay the onset of corrosion, but showed higher initial corrosion rates, once established, as compared with polished Mg surfaces. Slightly improved performance of the coatings was achieved through the addition of H2 to the system which acted to inhibit Al-Mg alloying and MgO formation. However, localized accelerated corrosion associated with substrate polishing damage emphasized the need for improved process control and coating uniformity.

Demonstration of Thermally Sprayed Metal and Polymer Coatings for Steel Structures at Fort Bragg, NC

DTIC Science & Technology

2017-09-01

for Steel Structures at Fort Bragg, NC Final Report on Project F07-AR10 Co ns tr uc tio n En gi ne er in g R es ea rc h La bo ra to ry Larry D...and Polymer Coatings for Steel Structures at Fort Bragg, NC Final Report on Project F07-AR10 Larry D. Stephenson, Alfred D. Beitelman, Richard G...recently been estimated that at least 25 U.S. Army in- stallations have severe corrosion problems with above-ground steel stor- age tanks. Coatings are

Mechanism for the Cellular Uptake of Targeted Gold Nanorods of Defined Aspect Ratios.

PubMed

Yang, Hongrong; Chen, Zhong; Zhang, Lei; Yung, Wing-Yin; Leung, Ken Cham-Fai; Chan, Ho Yin Edwin; Choi, Chung Hang Jonathan

2016-10-01

Biomedical applications of non-spherical nanoparticles such as photothermal therapy and molecular imaging require their efficient intracellular delivery, yet reported details on their interactions with the cell remain inconsistent. Here, the effects of nanoparticle geometry and receptor targeting on the cellular uptake and intracellular trafficking are systematically explored by using C166 (mouse endothelial) cells and gold nanoparticles of four different aspect ratios (ARs) from 1 to 7. When coated with poly(ethylene glycol) strands, the cellular uptake of untargeted nanoparticles monotonically decreases with AR. Next, gold nanoparticles are functionalized with DNA oligonucleotides to target Class A scavenger receptors expressed by C166 cells. Intriguingly, cellular uptake is maximized at a particular AR: shorter nanorods (AR = 2) enter C166 cells more than nanospheres (AR = 1) and longer nanorods (AR = 4 or 7). Strikingly, long targeted nanorods align to the cell membrane in a near-parallel manner followed by rotating by ≈90° to enter the cell via a caveolae-mediated pathway. Upon cellular entry, targeted nanorods of all ARs predominantly traffic to the late endosome without progressing to the lysosome. The studies yield important materials design rules for drug delivery carriers based on targeted, anisotropic nanoparticles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Composite films prepared by plasma ion-assisted deposition (IAD) for design and fabrication of antireflection coatings in visible and near-infrared spectral regions

NASA Astrophysics Data System (ADS)

Tsai, Rung-Ywan; Ho, Fang C.

1994-11-01

Ion-assisted deposition (IAD) processes configured with a well-controlled plasma source at the center base of a vacuum chamber, which accommodates two independent e-gun sources, is used to deposition TiO2MgF2 and TiO2-SiO2 composite films of selected component ratios. Films prepared by this technology are found durable, uniform, and nonabsorbing in visible and near-IR regions. Single- and multilayer antireflection coatings with refractive index from 1.38 to 2.36 at (lambda) equals 550 nm are presented. Methods of enhancement in optical performance of these coatings are studied. The advantages of AR coatings formed by TiO2-MgF2 composite films over those similar systems consisting of TiO2-SiO2 composite films in both visible and near-IR regions are also presented.

Random Surface Texturing of Silicon Dioxide Using Gold Agglomerates

DTIC Science & Technology

2016-07-01

Approved for public release; distribution unlimited. 1 1. Introduction The US Army has been developing new types of photovoltaic ( PV ) devices— solar ...light falling onto the surface of a solar cell is a major optical loss mechanism, which limits the efficiency of the PV .1,2 One method of reducing...in an AR coating on solar cells. 15. SUBJECT TERMS anti-reflective, AR coatings, textured surface structures, silicon dioxide, SiO2 16. SECURITY

Humic acid facilitates the transport of ARS-labeled hydroxyapatite nanoparticles in iron oxyhydroxide-coated sand.

PubMed

Wang, Dengjun; Bradford, Scott A; Harvey, Ronald W; Gao, Bin; Cang, Long; Zhou, Dongmei

2012-03-06

Hydroxyapatite nanoparticles (nHAP) have been widely used to remediate soil and wastewater contaminated with metals and radionuclides. However, our understanding of nHAP transport and fate is limited in natural environments that exhibit significant variability in solid and solution chemistry. The transport and retention kinetics of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated packed columns that encompassed a range of humic acid concentrations (HA, 0-10 mg L(-1)), fractional surface coverage of iron oxyhydroxide coatings on sand grains (λ, 0-0.75), and pH (6.0-10.5). HA was found to have a marked effect on the electrokinetic properties of ARS-nHAP, and on the transport and retention of ARS-nHAP in granular media. The transport of ARS-nHAP was found to increase with increasing HA concentration because of enhanced colloidal stability and the reduced aggregate size. When HA = 10 mg L(-1), greater ARS-nHAP attachment occurred with increasing λ because of increased electrostatic attraction between negatively charged nanoparticles and positively charged iron oxyhydroxides, although alkaline conditions (pH 8.0 and 10.5) reversed the surface charge of the iron oxyhydroxides and therefore decreased deposition. The retention profiles of ARS-nHAP exhibited a hyperexponential shape for all test conditions, suggesting some unfavorable attachment conditions. Retarded breakthrough curves occurred in sands with iron oxyhydroxide coatings because of time-dependent occupation of favorable deposition sites. Consideration of the above effects is necessary to improve remediation efficiency of nHAP for metals and actinides in soils and subsurface environments.

Exploration of the horizontally staggered light guides for high concentration CPV applications.

PubMed

Selimoglu, Ozgur; Turan, Rasit

2012-08-13

The material and processing costs are still the major drawbacks of the c-Si based photovoltaic (PV) technology. The wafer cost comprises up to 35-40% of the total module cost. New approaches and system designs are needed in order to reduce the share of the wafer cost in photovoltaic energy systems. Here we explore the horizontally staggered light guide solar optics for use in Concentrated Photovoltaic (CPV) applications. This optical system comprises a lens array system coupled to a horizontal light guide which directs the incoming light beam to its edge. We have designed and simulated this system using a commercial ray tracing software (Zemax). The system is more compact, thinner and more robust compared to the conventional CPV systems. Concentration levels as high as 1000x can easily be reached when the system is properly designed. With such a high concentration level, a good acceptance angle of + -1 degree is still be conserved. The analysis of the system reveals that the total optical efficiency of the system could be as high as %94.4 without any anti-reflection (AR) coating. Optical losses can be reduced by just accommodating a single layer AR coating on the initial lens array leading to a %96.5 optical efficiency. Thermal behavior of high concentration linear concentrator is also discussed and compared with a conventional point focus CPV system.

The Broadband Anti-reflection Coated Extended Hemispherical Silicon Lenses for Polarbear-2 Experiment

NASA Astrophysics Data System (ADS)

Siritanasak, P.; Aleman, C.; Arnold, K.; Cukierman, A.; Hazumi, M.; Kazemzadeh, K.; Keating, B.; Matsumura, T.; Lee, A. T.; Lee, C.; Quealy, E.; Rosen, D.; Stebor, N.; Suzuki, A.

2016-08-01

Polarbear-2 (PB-2) is a next-generation receiver that is part of the Simons Array cosmic microwave background (CMB) polarization experiment which is located in the Atacama desert in Northern Chile. The primary scientific goals of the Simons Array are a deep search for the CMB B-mode signature of gravitational waves from inflation and the characterization of large-scale structure using its effect on CMB polarization. The PB-2 receiver will deploy with 1897 dual-polarization sinuous antenna-coupled pixels, each with a directly contacting extended hemispherical silicon lens. Every pixel has dual polarization sensitivity in two spectral bands centered at 95 and 150 GHz, for a total of 7588 transition edge sensor bolometers operating at 270 mK. To achieve the PB-2 detector requirements, we developed a broadband anti-reflection (AR) coating for the extended hemispherical lenses that uses two molds to apply two layers of epoxy, Stycast 1090 and Stycast 2850FT. Our measurements of the absorption loss from the AR coating on a flat surface at cryogenic temperatures show less than 1 % absorption, and the coating has survived multiple thermal cycles. We can control the diameter of the coating within 25 {\\upmu }m and translation errors are within 25 {\\upmu }m in all directions, which results in less than 1 % decrease in transmittance. We also find the performance of the AR-coated lens matches very well with simulations.

Broadband optical antireflection enhancement by integrating antireflective nanoislands with silicon nanoconical-frustum arrays.

PubMed

Park, Haesung; Shin, Dongheok; Kang, Gumin; Baek, Seunghwa; Kim, Kyoungsik; Padilla, Willie J

2011-12-22

Based on conventional colloidal nanosphere lithography, we experimentally demonstrate novel graded-index nanostructures for broadband optical antireflection enhancement including the near-ultraviolet (NUV) region by integrating residual polystyrene antireflective (AR) nanoislands coating arrays with silicon nano-conical-frustum arrays. This is a feasible optimized integration method of two major approaches for antireflective surfaces: quarter-wavelength AR coating and biomimetic moth's eye structure. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Logic Nanocells Within 3-Terminal Ordered Arrays

DTIC Science & Technology

2007-02-28

DISTRIBUTION/AVAILABILITY STATEMENT DISTRIBUTION STATEMEN A: UNLIMITED AFRL- SR -AR-TR-07-0494 13. SUPPLEMENTARY NOTES 14. ABSTRACT ON SEPARATE SHEET... sputter -coating a 200 nm Au layer. Molecular grafting. Compounds 1, 2 and 3 were synthesized according to literature methods.24 26 The synthesis of 4...neutral (no counter ions ). In order to facilitate molecular conduction, the molecule was designed to be small and contain a continuous Tr-electron system

Preparation, characterization and in vitro response of bioactive coatings on polyether ether ketone.

PubMed

Durham, John W; Allen, Matthew J; Rabiei, Afsaneh

2017-04-01

Polyether ether ketone (PEEK) is a highly heat-resistant thermoplastic with excellent strength and elastic modulus similar to human bone, making it an attractive material for orthopedic implants. However, the hydrophobic surface of PEEK implants induces fibrous encapsulation which is unfavorable for stable implant anchorage. In this study, PEEK was coated via ion-beam-assisted deposition (IBAD) using a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to improve osseointegration. Microstructural analysis of the coatings showed a dense, uniform columnar grain structure in the YSZ layer and no delamination from the substrate. The HA layer was found to be amorphous and free of porosities in its as-deposited state. Subsequent heat treatment via microwave energy followed by autoclaving crystallized the HA layer, confirmed by SEM and XRD analysis. An in vitro study using MC3T3 preosteoblast cells showed improved bioactivity in heat-treated sample groups. Cell proliferation, differentiation, and mineralization were analyzed by MTT assay and DNA content, osteocalcin expression, and Alizarin Red S (AR-S) content, respectively. Initial cell growth was increased, and osteogenic maturation and mineralization were accelerated most on coatings that underwent a combined microwave and autoclave heat treatment process as compared to uncoated PEEK and amorphous HA surfaces. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 560-567, 2017. © 2015 Wiley Periodicals, Inc.

Humic acid facilitates the transport of ARS-labeled hydroxyapatite nanoparticles in iron oxyhydroxide-coated sand

USGS Publications Warehouse

Wang, Dengjun; Bradford, Scott A.; Harvey, Ronald W.; Gao, Bin; Cang, Long; Zhou, Dongmei

2012-01-01

Hydroxyapatite nanoparticles (nHAP) have been widely used to remediate soil and wastewater contaminated with metals and radionuclides. However, our understanding of nHAP transport and fate is limited in natural environments that exhibit significant variability in solid and solution chemistry. The transport and retention kinetics of Alizarin red S (ARS)-labeled nHAP were investigated in water-saturated packed columns that encompassed a range of humic acid concentrations (HA, 0–10 mg L–1), fractional surface coverage of iron oxyhydroxide coatings on sand grains (λ, 0–0.75), and pH (6.0–10.5). HA was found to have a marked effect on the electrokinetic properties of ARS-nHAP, and on the transport and retention of ARS-nHAP in granular media. The transport of ARS-nHAP was found to increase with increasing HA concentration because of enhanced colloidal stability and the reduced aggregate size. When HA = 10 mg L–1, greater ARS-nHAP attachment occurred with increasing λ because of increased electrostatic attraction between negatively charged nanoparticles and positively charged iron oxyhydroxides, although alkaline conditions (pH 8.0 and 10.5) reversed the surface charge of the iron oxyhydroxides and therefore decreased deposition. The retention profiles of ARS-nHAP exhibited a hyperexponential shape for all test conditions, suggesting some unfavorable attachment conditions. Retarded breakthrough curves occurred in sands with iron oxyhydroxide coatings because of time-dependent occupation of favorable deposition sites. Consideration of the above effects is necessary to improve remediation efficiency of nHAP for metals and actinides in soils and subsurface environments.

TPV Power Source Using Infrared-Sensitive Cells with Commercially Available Radiant Tube Burner

NASA Astrophysics Data System (ADS)

Fraas, Lewis; Minkin, Leonid; Hui, She; Avery, James; Howells, Christopher

2004-11-01

Over the last several years, JX Crystals has invented and systematically developed the key components for thermophotovoltaic systems. These key components include GaSb infrared sensitive cells, high power density shingle circuits, dielectric filters, and hydrocarbon-fueled radiant tube burners. Most recently, we invented and demonstrated an antireflection (AR)-coated tungsten IR emitter which when integrated with the other key components should make TPV systems with efficiencies over 10% practical. However, the use of the AR tungsten emitter requires an oxygen-free hermetic seal enclosure. During a 2003 Small Business Innovative Research (SBIR) Phase I contract, we integrated a tungsten emitter foil and a commercial SiC radiant tube burner within an emitter thermos and successfully demonstrated its operation at high temperature. We also designed a complete stand alone 500 W TPV generator. During the upcoming SBIR Phase II, we plan to implement this design in hardware.

Compositionally modulated multilayer diamond-like carbon coatings with AlTiSi multi-doping by reactive high power impulse magnetron sputtering

NASA Astrophysics Data System (ADS)

Dai, Wei; Gao, Xiang; Liu, Jingmao; Kwon, Se-Hun; Wang, Qimin

2017-12-01

Diamond-like carbon (DLC) coatings with AlTiSi multi-doping were prepared by a reactive high power impulse magnetron sputtering with using a gas mixture of Ar and C2H2 as precursor. The composition, microstructure, compressive stress, and mechanical property of the as-deposited DLC coatings were studied systemically by using SEM, XPS, TEM, Raman spectrum, stress-tester, and nanoindentation as a function of the Ar fraction. The results show that the doping concentrations of the Al, Ti and Si atoms increased as the Ar fraction increased. The doped Ti and Si preferred to bond with C while the doped Al mainly existed in oxidation state without bonding with C. As the doping concentrations increased, TiC carbide nanocrystals were formed in the DLC matrix. The microstructure of coatings changed from an amorphous feature dominant AlTiSi-DLC to a carbide nanocomposite AlTiSi-DLC with TiC nanoparticles embedding. In addition, the coatings exhibited the compositionally modulated multilayer consisting of alternate Al-rich layer and Al-poor layer due to the rotation of the substrate holder and the diffusion behavior of the doped Al which tended to separate from C and diffuse towards the DLC matrix surface owing to its weak interactions with C. The periodic Al-rich layer can effectively release the compressive stress of the coatings. On the other hand, the hard TiC nanoparticles were conducive to the hardness of the coatings. Consequently, the DLC coatings with relatively low residual stress and high hardness could be acquired successfully through AlTiSi multi-doping. It is believed that the AlCrSi multi-doping may be a good way for improving the comprehensive properties of the DLC coatings. In addition, we believe that the DLC coatings with Al-rich multilayered structure have a high oxidation resistance, which allows the DLC coatings application in high temperature environment.

Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials

PubMed Central

Nikzad, Shouleh; Hoenk, Michael; Jewell, April D.; Hennessy, John J.; Carver, Alexander G.; Jones, Todd J.; Goodsall, Timothy M.; Hamden, Erika T.; Suvarna, Puneet; Bulmer, J.; Shahedipour-Sandvik, F.; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L. Douglas

2016-01-01

Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100–300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness. PMID:27338399

Multifunctional overcoats on vanadium dioxide thermochromic thin films with enhanced luminous transmission and solar modulation, hydrophobicity and anti-oxidation

NASA Astrophysics Data System (ADS)

Liu, Chang; Wang, Ning; Long, Yi

2013-10-01

Vanadium dioxide (VO2) has a great potential to be utilized as solar energy switching glazing, even though there exist some intrinsic problems of low luminous transmittance (Tlum) and poor oxidation resistance. Si-Al based anti-reflection (AR) sol-gel coatings processed at low temperature have been developed to tackle these issues assisted by adjusting ramping rate and annealing temperature. Si-Al based AR coating gives large relative enhancement on the transmittance (22% for Tlum, 14% for the whole solar spectrum Tsol,) and successfully maintains IR contrast at 2500 nm wavelength with 18% relative increase in solar modulation (ΔTsol). The optimized Si-Al based AR coating annealing conditions are recorded at 3 °C/min ramping rate and 100 °C annealing temperature. Fluorinated-Si based gel offers a new direction of multifunctional overcoat on thermochromic smart windows with hydrophobicity (contact angle 111°), averaged 14% relatively increased luminous transmittance and enhanced oxidation resistance.

Single Photon Counting UV Solar-Blind Detectors Using Silicon and III-Nitride Materials.

PubMed

Nikzad, Shouleh; Hoenk, Michael; Jewell, April D; Hennessy, John J; Carver, Alexander G; Jones, Todd J; Goodsall, Timothy M; Hamden, Erika T; Suvarna, Puneet; Bulmer, J; Shahedipour-Sandvik, F; Charbon, Edoardo; Padmanabhan, Preethi; Hancock, Bruce; Bell, L Douglas

2016-06-21

Ultraviolet (UV) studies in astronomy, cosmology, planetary studies, biological and medical applications often require precision detection of faint objects and in many cases require photon-counting detection. We present an overview of two approaches for achieving photon counting in the UV. The first approach involves UV enhancement of photon-counting silicon detectors, including electron multiplying charge-coupled devices and avalanche photodiodes. The approach used here employs molecular beam epitaxy for delta doping and superlattice doping for surface passivation and high UV quantum efficiency. Additional UV enhancements include antireflection (AR) and solar-blind UV bandpass coatings prepared by atomic layer deposition. Quantum efficiency (QE) measurements show QE > 50% in the 100-300 nm range for detectors with simple AR coatings, and QE ≅ 80% at ~206 nm has been shown when more complex AR coatings are used. The second approach is based on avalanche photodiodes in III-nitride materials with high QE and intrinsic solar blindness.

Calculation and synthesis of ZrC by CVD from ZrCl4-C3H6-H2-Ar system with high H2 percentage

NASA Astrophysics Data System (ADS)

Zhu, Yan; Cheng, Laifei; Ma, Baisheng; Gao, Shuang; Feng, Wei; Liu, Yongsheng; Zhang, Litong

2015-03-01

A thermodynamic calculation about the synthesis of ZrC from the ZrCl4-C3H6-H2-Ar system with high percentage of H2 was performed using the FactSage thermochemical software. According to the calculation, ZrC coating was synthesized on graphite substrates and carbon fibers by a low pressure chemical vapor deposition (LPCVD) process, and growth rate of the ZrC coating as a function of temperature was investigated. The surface diagrams of condensed-phases in this system were expressed as the functions of the deposition temperature, total pressure and reactant ratios of ZrCl4/(ZrCl4 + C3H6), H2/(ZrCl4 + C3H6), and the yield of the products was determined by the diagrams. A smooth and dense ZrC coating could be synthesized under the instruction of the calculated parameters. The morphologies of the ZrC coatings were significantly affected by temperature and gases flux. The deposition temperature is much lower than that from the ZrCl4-CH4-H2-Ar system.

Development of high-efficiency solar cells on silicon web

NASA Technical Reports Server (NTRS)

Rohatgi, A.; Meier, D. L.; Campbell, R. B.; Seidensticker, R. G.; Rai-Choudhury, P.

1985-01-01

High-efficiency dendritic cells were discussed. The influence of twin planes and heat treatment on the location and effect of trace impurities was of particular interest. Proper heat treatment often increases efficiency by causing impurities to pile up at twin planes. Oxide passivation had a beneficial effect on efficiency. A very efficient antireflective (AR) coating of zinc selenide and magnesium fluoride was designed and fabricated. An aluminum back-surface reflector was also effective.

Materials and Manufacturing Processes. Volume 9. Number 1

DTIC Science & Technology

1994-01-01

and Coatings Technology , Vol.36, No.9, p.1429, (1987). p.303, (1988). 45. Badzian, A.R., Advances in X-ray 53. Suzuki, H., H. Matsubavo, and N. Analysis... Technology Division of Metallurgy, N-7034 Trondheim, Norway E. Bathen Microscan, Tonstadgrenda 23, N-7075 Tiller, Norway D. 0ymo and Norsk Hydro A.S...these materials both in general technology behind traditional design and manufacture. Special and advanced ceramics. It also gives the considerations

Ta2O5/ Al2O3/ SiO2 - antireflective coating for non-planar optical surfaces by atomic layer deposition

NASA Astrophysics Data System (ADS)

Pfeiffer, K.; Schulz, U.; Tünnermann, A.; Szeghalmi, A.

2017-02-01

Antireflective coatings are essential to improve transmittance of optical elements. Most research and development of AR coatings has been reported on a wide variety of plane optical surfaces; however, antireflection is also necessary on nonplanar optical surfaces. Physical vapor deposition (PVD), a common method for optical coatings, often results in thickness gradients on strongly curved surfaces, leading to a failure of the desired optical function. In this work, optical thin films of tantalum pentoxide, aluminum oxide and silicon dioxide were prepared by atomic layer deposition (ALD), which is based on self-limiting surface reactions. The results demonstrate that ALD optical layers can be deposited on both vertical and horizontal substrate surfaces with uniform thicknesses and the same optical properties. A Ta2O5/Al2O3/ SiO2 multilayer AR coating (400-700 nm) was successfully applied to a curved aspheric glass lens with a diameter of 50 mm and a center thickness of 25 mm.

Effect of Ultraviolet Exposure on Impact Resistance of Ophthalmic Lenses.

PubMed

Chou, B Ralph; Dain, Stephen J; Cheng, Brian B

2015-12-01

To investigate the effect of ultraviolet radiation (UVR) on the impact resistance of organic ophthalmic lens materials. Plano power CR39, Phoenix, Trilogy, and polycarbonate lenses with various scratch-resistant (SR) and/or antireflection (AR) coatings were obtained in batches of 40 units. All lenses had a nominal thickness of 2 mm. Half of each batch was conditioned following the European Standard EN 168 protocol for the test of resistance to UVR (exposed group). The remaining lenses comprised an unexposed group for that combination of lens substrate and coating treatment. Each group was subjected to ballistic impact with 6-mm steel balls following the ZEST protocol to determine its mean breakage velocity. The difference in mean breakage velocity between exposed and unexposed groups of each combination of lens substrate and coating was assessed for statistical significance. Exposed uncoated CR39 showed a reduction in fracture velocity of 10.3 m/s whereas CR39 with ultra hard coat had a reduction of 3.5 m/s and CR39 with AR and SR coating had a reduction of 4.1 m/s. Scratch-resistant coated Phoenix had a reduction of 4.8 m/s whereas AR-coated Phoenix had a reduction of 3.7 m/s. The corresponding reductions for Trilogy were 3.9 and 17.8 m/s. All differences were significant at the p level of less than 0.05. Although we were unable to break unexposed SR-coated polycarbonate lenses with our test apparatus, exposed SR-coated polycarbonate had a mean breakage velocity of 142 m/s. Our data suggest that extended UVR exposure causes a significant reduction in the impact resistance of the ophthalmic lens substrates commonly used for occupational eye protectors. Protective lenses that have been exposed to high levels of UVR for extended periods should be replaced regularly to maintain optimal impact protection, even if they do not show visible damage owing to wear and tear.

Effect of Ar{sup +} ion irradiation on the microstructure of pyrolytic carbon

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

Feng, Shanglei; Zhang, Dongsheng; Yang, Xinmei

2015-03-21

Pyrolytic carbon (PyC) coatings prepared by chemical vapor deposition were irradiated by 300 keV Ar{sup +} ions. Then, atomic force microscopy, synchrotron-based grazing incidence X-ray diffraction, Raman spectroscopy, X-ray photoemission spectroscopy, and transmission electron microscopy were employed to study how Ar{sup +} irradiation affects the microstructure of PyC, including the microstructural damage mechanisms and physics driving these phenomena. The 300 keV Ar{sup +} ion irradiation deteriorated the structure along the c-axis, which increased the interlayer spacing between graphene layers. With increasing irradiation dose, the density of defect states on the surface of PyC coating increases, and the basal planes gradually loses theirmore » initial ordering resulting in breaks in the lattice and turbulence at the peak damage dose reaches 1.58 displacement per atom (dpa). Surprisingly, the PyC becomes more textured as it becomes richer in structural defects with increasing irradiation dose.« less

AR coatings on laser crystals for HiPER project

NASA Astrophysics Data System (ADS)

Oulehla, Jindřich; Pokorný, Pavel

2010-08-01

In this contribution we present a technology for deposition of interference coatings for optical components designed to operate as active media in power pulsed lasers. The aim of the technology is to prepare crystals for lasers for the HiPER project (High Power laser Energy Research) which should demonstrate the feasibility of laser driven fusion as a future energy source. Diode pumped solid state lasers (DPSSL) are the most likely option for fusion ignition. The choice of material for the lasers active medium is critical. Some of the most important properties include the ability to be antireflection coated to reduce the energy losses and increase the overall efficiency. This contribution deals with some of the materials considered to be candidates for slabs serving as the active medium of the DPSSLs. We tested Yb:YAG, Yb:CaF2 samples. As large amounts of heat need to be dissipated during laser operation, cryogenic cooling is necessary. Appropriate coating materials and techniques need to be chosen. Therefore differences between available coating techniques are investigated in terms of adhesion, enduring of stress resulting from temperature shocks, etc. Coated samples were placed into cryogenic environment in order to simulate conditions similar to those in real life operation. Optical microscopy was used for coating investigation after the conducted experiments.

Implementation of Polyurea Applications for Wastewater System Corrosion-Mitigation Projects: Final Report on Project F15-AR04

DTIC Science & Technology

2017-07-24

Corrosion-Mitigation Projects Final Report on Project F15-AR04 Co ns tr uc tio n En gi ne er in g R es ea rc h La bo ra to ry Clint A. Wilson...2017 Implementation of Polyurea Applications for Wastewater System Corrosion-Mitigation Projects Final Report on Project F15-AR04 Clint A...Secretary of Defense Washington, DC 20301-3090 Under Project F15-AR04, “Polyurea Coating for Rehabilitation of Concrete and Metal Infrastructure

High Speed Modulation, Beam Steering and Control of High Power Diode Lasers

DTIC Science & Technology

2000-03-03

designing the interactive simulator in such a way that the user will be able to probe the system and change parameters on the fly. Pull -down menus will...AR and HR coatings, beam splitters, external cavities, etc) can be built and accessed via pull -down menus within an optical systems graphical GUI...supported in part by the National Science Foundation’s GOALI program under grant number DM59811466 and AFOSR under contract number F49620-97-1-0002 and

PEG-coated gold nanoparticles attenuate β-adrenergic receptor-mediated cardiac hypertrophy.

PubMed

Qiao, Yuhui; Zhu, Baoling; Tian, Aiju; Li, Zijian

2017-01-01

Gold nanoparticles (AuNPs) are widely used as a drug delivery vehicle, which can accumulate in the heart through blood circulation. Therefore, it is very important to understand the effect of AuNPs on the heart, especially under pathological conditions. In this study, we found that PEG-coated AuNPs attenuate β-adrenergic receptor (β-AR)-mediated acute cardiac hypertrophy and inflammation. However, both isoproterenol, a non-selective β-AR agonist, and AuNPs did not induce cardiac function change or cardiac fibrosis. AuNPs exerted an anti-cardiac hypertrophy effect by decreasing β 1 -AR expression and its downstream ERK1/2 hypertrophic pathway. Our results indicated that AuNPs might be safe and have the potential to be used as multi-functional materials (drug carrier systems and anti-cardiac hypertrophy agents).

Laser damage of HR, AR-coatings, monolayers and bare surfaces at 1064 nm

NASA Technical Reports Server (NTRS)

Garnov, S. V.; Klimentov, S. M.; Said, A. A.; Soileau, M. J.

1993-01-01

Laser induced damage thresholds and morphologies were investigated in a variety of uncoated and coated surfaces, including monolayers and multi-layers of different chemical compositions. Both antireflective (AR) and highly reflective (HR) were tested. Testing was done at 1064 nm with 25 picosecond and 8 nanosecond YAG/Nd laser single pulses. Spot diameter in the experiments varied from 0.09 to 0.22 mm. The laser damage measurement procedure consisted of 1-on-1 (single laser pulse in the selected site) and N-on-1 experiments including repeated irradiation by pulses of the same fluence and subsequently raised from pulse to pulse fluence until damage occurred. The highest picosecond damage thresholds of commercially available coatings averaged 12 - 14 J/sq cm, 50 percent less than thresholds obtained in bare fused silica. Some coatings and bare surfaces revealed a palpable preconditioning effect (an increase in threshold of 1.2 to 1.8 times). Picosecond and nanosecond data were compared to draw conclusions about pulse width dependence. An attempt was made to classify damage morphologies according to the type of coating, class of irradiating, and damage level.

Improved HgCdTe detectors with novel antireflection coating

NASA Astrophysics Data System (ADS)

Babu, Sachi R.; Hu, Kelley; Manthripragada, Sridhar; Martineau, Robert J.; Kotecki, C. A.; Peters, F. A.; Burgess, A. S.; Krebs, Danny J.; Mott, David B.; Ewin, Audrey J.; Miles, A.; Nguyen, Trang L.; Shu, Peter K.

1996-10-01

The composite infrared spctrometer (CIRS) is an important instrument for the upcoming Cassini mission for sensing infrared (IR) radiation from the Saturanian planetary system. We have delivered a linear, ten element, mercury cadmium telluride (HgCdTe) photoconductive detector array for use on focal plane 3 (FP3), which is responsible for detecting radiation from the 9.1 micrometer to 16.6 micrometer wavelength range. Reliable HgCdTe detectors require robust passivation, a low-stress zinc sulfide (ZnS) anti-reflection (AR) coating with good adhesion, and a proper optical cavity design to smooth out the resonance in the detector spectral response. During the development of CIRS flight array, we have demonstrated the potential of using an in-situ interfacial layer, such as SiN(subscript x), between ZnS and the anodic oxide. Such an interfacial layer drastically improves the adhesion between the ZnS and oxide, without degrading the minority carrier lifetime. We have also demonstrated the feasibility of applying a SiN(subscript x) 'rain coat' layer over the ZnS to prevent moisture and other chemicals from attacking the AR coating, thus improving the long term reliability. This also enables device operation in a hazardous environment. The alumina/epoxy/HgCdTe/oxide/ZnS structure is a complicated multi-cavity optical system. We have developed an extensive device simulation, which enables us to make the optimal choice of individual cavity thickness for minimizing the resonance and maximizing the quantum efficiency. We have also used 0.05 micrometer alumina powder loaded epoxy to minimize the reflections at the epoxy/HgCdTe interface, thus minimizing the resonance.

Plasma Spray-Physical Vapor Deposition (PS-PVD) of Ceramics for Protective Coatings

NASA Technical Reports Server (NTRS)

Harder, Bryan J.; Zhu, Dongming

2011-01-01

In order to generate advanced multilayer thermal and environmental protection systems, a new deposition process is needed to bridge the gap between conventional plasma spray, which produces relatively thick coatings on the order of 125-250 microns, and conventional vapor phase processes such as electron beam physical vapor deposition (EB-PVD) which are limited by relatively slow deposition rates, high investment costs, and coating material vapor pressure requirements. The use of Plasma Spray - Physical Vapor Deposition (PS-PVD) processing fills this gap and allows thin (< 10 microns) single layers to be deposited and multilayer coatings of less than 100 microns to be generated with the flexibility to tailor microstructures by changing processing conditions. Coatings of yttria-stabilized zirconia (YSZ) were applied to NiCrAlY bond coated superalloy substrates using the PS-PVD coater at NASA Glenn Research Center. A design-of-experiments was used to examine the effects of process variables (Ar/He plasma gas ratio, the total plasma gas flow, and the torch current) on chamber pressure and torch power. Coating thickness, phase and microstructure were evaluated for each set of deposition conditions. Low chamber pressures and high power were shown to increase coating thickness and create columnar-like structures. Likewise, high chamber pressures and low power had lower growth rates, but resulted in flatter, more homogeneous layers

Nanocrystalline CeO2-δ coated β-MnO2 nanorods with enhanced oxygen transfer property

NASA Astrophysics Data System (ADS)

Huang, Xiubing; Zhao, Guixia; Chang, Yueqi; Wang, Ge; Irvine, John T. S.

2018-05-01

In this research, β-MnO2 nanorods were synthesized by a hydrothermal method, followed by a facile precipitation method to obtain nanocrystalline CeO2-δ coated β-MnO2 nanorods. The as-prepared samples were characterized by XRD, HRTEM, FESEM, XPS and in-situ high-temperature XRD. The HRTEM results show that well dispersed CeO2-δ nanocrystals sized about 5 nm were coated on the surface of β-MnO2 nanorods. The oxygen storage and transfer property of as-synthesized materials were evaluated using TGA under various atmospheres (air, pure N2, and 5%H2/95%Ar). The TGA results indicate that CeO2-δ modification could favour the reduction of Mn4+ to Mn3+ and/or Mn2+ at lower temperature as compared with pure β-MnO2 nanorods and the physically mixed CeO2-δ-β-MnO2 under low oxygen partial pressure conditions (i.e., pure N2, 5%H2/95%Ar). Specifically, CeO2-δ@β-MnO2 sample can exhibit 7.5 wt% weight loss between 100 and 400 °C under flowing N2 and 11.4 wt% weight loss between 100 and 350 °C under flowing 5%H2/95%Ar. During the reduction process under pure N2 or 5%H2/95%Ar condition, the oxygen ions in β-MnO2 nanorods are expected to be released to the surroundings in the form of O2 or H2O with the coated CeO2-δ nanocrystals acting as mediator as inferred from the synergistic effect between the well-interacted CeO2-δ nanocrystals and β-MnO2 nanorods.

UV testing of INTELSAT-7, 7A, and 8 solar cells

NASA Technical Reports Server (NTRS)

Meulenberg, A.

1994-01-01

A 4000 hour experiment, conducted in late 1992 through mid 1993, confirmed earlier results on the ultraviolet damage effects in covered solar cells of various types being used, or proposed for use, in INTELSAT programs. Two different UV test systems were used to identify systematic errors and to study the effects of UV source-bulb age on degradation rate. After correction for contamination and UV source-bulb aging, the extrapolated degradation rates for irradiated and unirradiated INTELSAT-5, -6 single AR(SAR) coated cells and INTELSAT-7, -7A, -8 double layer AR(DAR) coated cells in both the 1993 tests confirm the following hypotheses resulting from the 1992 experiment. (a) Irradiated cells display significantly more UV degradation than do the unirradiated cells for tests exceeding 2000 hours. The new data indicates that degradation effects from electron irradiation are proportional to t(exp 2) (the square of the UV hours), at least for times less than or equal to 3000 hours. (b) This difference does not depend upon entire reflective coating, cell resistivity, or manufacturer within the sensitivity and reproducibility of the experiment. (c) There is a clear difference in degradation rate between single AR coated cells (TiO(x)) and double layer AR coated cells (SiO(x) and Al2O3?). At 100,000 hours (11.4 years) the DAR coated cells display more degradation than do the SAR coated cells, even though at 1,000 hours the DAR cells display less degradation. (d) UV degradation rates, to modern covered silicon solar cells, at the beginning of bulb life drop from approximately 2 times the average rate to near zero after 2000 hours (average end-of-life for the xenon short-arc lamps used in the tests). The effects of 1 MeV electron irradiation (10(exp 15) e(-)/sq cm) prior to UV exposure are clearly indicated in the plot of percent change in cell open circuit voltage (Voc) versus percent change in short circuit current (Isc) during the UV test and post-test cleanup of the cells. Clearly, extended UV testing produces a permanent photo-induced redegradation of previously irradiated cells. However, this photo-induced redegradation may be caused by the long-wavelength light, not the UV light.

Development of high-efficiency solar cells on silicon web

NASA Technical Reports Server (NTRS)

Meier, D. L.

1986-01-01

Achievement of higher efficiency cells by directing efforts toward identifying carrier loss mechanisms; design of cell structures; and development of processing techniques are described. Use of techniques such as deep-level transient spectroscopy (DLTS), laser-beam-induced current (LBIC), and transmission electron microscopy (TEM) indicated that dislocations in web material rather than twin planes were primarily responsible for limiting diffusion lengths in the web. Lifetimes and cell efficiencies can be improved from 19 to 120 microns, and 8 to 10.3% (no AR), respectively, by implanting hydrogen at 1500 eV and a beam current density of 2.0 mA/sq cm. Some of the processing improvements included use of a double-layer AR coating (ZnS and MgF2) and an addition of an aluminum back surface reflectors. Cells of more than 16% efficiency were achieved.

Status of Diffused Junction p(+)n InP Solar Cells for Space Applications

NASA Technical Reports Server (NTRS)

Faur, Mircea; Faur, Maria; Flood, D. J.; Brinker, D. J.; Goradia, C.; Fatemi, N. S.; Jenkins, P. P.; Wilt, D. M.; Bailey, S.

1994-01-01

Recently, we have succeeded in fabricating diffused junction p(+)n(Cd,S) InP solar cells with measured AMO, 25 C open circuit voltage (V(sub OC)) of 887.6 mV, which, to the best of our knowledge, is higher than previously reported V(sub OC) values for any InP homojunction solar cells. The experiment-based projected achievable efficiency of these cells using LEC grown substrates is 21.3%. The maximum AMO, 25 C efficiency recorded to date on bare cells is, however, only 13.2%. This is because of large external and internal losses due to non-optimized front grid design, antireflection (AR) coating and emitter thickness. This paper summarizes recent advances in the technology of fabrication of p(+)n InP diffused structures and solar cells, resulted from a study undertaken in an effort to increase the cell efficiency. The topics discussed in this paper include advances in: 1) the formation of thin p(+) InP:Cd emitter layers, 2) electroplated front contacts, 3) surface passivation and 4) the design of a new native oxide/AI203/MgF2 three layer AR coating using a chemically-grown P-rich passivating oxide as a first layer. Based on the high radiation resistance and the excellent post-irradiation annealing and recovery demonstrated in the early tests done to date, as well as the projected high efficiency and low-cost high-volume fabricability, these cells show a very good potential for space photovoltaic applications.

Demonstration and Validation of Two Coat High Performance Coating System for Steel Structures in Corrosive Environments

DTIC Science & Technology

2016-12-01

System for Steel Structures in Corrosive Environments Final Report on Project F12-AR06 Co ns tr uc tio n En gi ne er in g R es ea rc h La bo ra...Prevention and Control Program ERDC/CERL TR-16-27 December 2016 Demonstration and Validation of Two-Coat High- Performance Coating System for Steel ...Performance Coating System for Steel Structures in Corrosive Environments” ERDC/CERL TR-16-27 ii Abstract Department of Defense (DoD) installations

Chiral mirror and optical resonator designs for circularly polarized light: suppression of cross-polarized reflectances and transmittances

NASA Astrophysics Data System (ADS)

Hodgkinson, Ian J.; Wu, Qi h.; Arnold, Matthew; McCall, Martin W.; Lakhtakia, Akhlesh

2002-09-01

A left-handed chiral sculptured thin film (STF) that reflects strongly at the wavelength of the circular Bragg resonance tends to partially convert the handedness of incident LCP (left-circularly-polarized) light to RCP (right-circularly-polarized). We show that the cross-polarized component of the reflected RCP beam can be eliminated by interference with an additional RCP beam that is reflected at the interface of an isotropic cover and an AR (antireflecting) layer. For best results the refractive index and thickness of the AR layer need to accommodate a phase change on reflection that occurs at the chiral film. Effective suppression of the reflectances RRR, RRL, RLR and the transmittances TRL, TLR can be achieved by sandwiching the chiral reflector between such amplitude and phase-matched AR coatings. Co-polarized chiral reflectors of this type may form efficient handed optical resonators. For LCP light the optical properties of such a handed resonator are formally the same as the properties of the isotropic passive or active Fabry-Perot resonators, but the handed resonator is transparent to RCP light.

Effect of template post-annealing on Y(Dy)BaCuO nucleation on CeO2 buffered metallic tapes

NASA Astrophysics Data System (ADS)

Hu, Xuefeng; Zhong, Yun; Zhong, Huaxiao; Fan, Feng; Sang, Lina; Li, Mengyao; Fang, Qiang; Zheng, Jiahui; Song, Haoyu; Lu, Yuming; Liu, Zhiyong; Bai, Chuanyi; Guo, Yanqun; Cai, Chuanbing

2017-08-01

Substrate engineering is very significant in the synthesis of the high-temperature superconductor (HTS) coated conductor. Here we design and synthesize several distinct and stable Cerium oxide (CeO2) surface reconstructions which are used to grow epitaxial films of the HTS YBa2Cu3O7-δ (YBCO). To identify the influence of annealing and post-annealing surroundings on the nature of nucleation centers, including Ar/5%H2, humid Ar/5%H2 and O2 in high temperature annealing process, we study the well-controlled structure, surface morphology, crystal constants and surface redox processes of the ceria buffers by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electronic microscopy (FE-SEM), respectively. The ceria film post-annealed under humid Ar/5%H2 gas shows the best buffer layer properties. Furthermore, the film absorbs more oxygen ions, which appears to contribute to oxygenation of superconductor film. The film is well-suited for ceria model studies as well as a perfect substitute for CeO2 bulk material.

Development of selective surfaces. Semiannual technical progress report, September 11, 1978-April 30, 1979. [Multilayer coatings

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

Thornton, J.A.

1979-06-15

Magnetron sputtering technology, which permits coatings to be deposited over large areas with significantly increased deposition rates, is reviewed with particular emphasis on cylindrical magnetrons and their application to reactive sputtering. Work is reported in which cylindrical-post magnetron sputtering sources have been used to deposit both graded and multi-layered cermet-type coatings by sputtering chromium and type 304 stainless steel in Ar and O/sub 2/ and Ar and CO gas mixtures under various conditions of reactive gas injection. The substrates are aluminum-coated glass and aluminum foil. The coatings are of an interference type, typically about 100 nm thick, with a metal-rich,more » highly absorbing layer adjacent to the substrate and a dielectric material at the surface. In some cases a reactively sputtered aluminum oxide anti-reflective surface layer has also been used. No advantages have been found for using chromium as opposed to the more readily available stainless steel. The reactive sputtering with CO is attractive because under many conditions the sputtering rates are relatively large compared to oxygen. Hemispherical absorptance and emittance data are reported. Typical absorptances are about 0.90 with emittances of 0.10.« less

Laser plasmatron for diamond coating deposition

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

Glova, A. F., E-mail: afglova@triniti.ru; Lysikov, A. Yu.; Malyuta, D. D.

2016-12-15

An experimental installation with a laser plasmatron based on a continuous wave CO{sub 2} laser with a radiation power of up to 3.5 kW has been created. The plasmatron design makes it possible to bring out the plasma jet into atmospheric air both along and across the laser beam direction. The spatial temperature distributions on the metal substrate surface heated by the plasma jet are measured. The threshold power for optical discharge maintenance as a function of the gas flow rate and the focal length of the focusing lens are obtained for an Ar and Ar/CH{sub 4}/H{sub 2} gas mixturemore » under atmospheric pressure; the radiation spectrum of the discharge plasma is measured. A one-dimensional model of the discharge for estimation of its geometrical parameters in a convergent laser beam with consideration of radiation refraction on the discharge is given.« less

Novel Prospects for Plasma Spray-Physical Vapor Deposition of Columnar Thermal Barrier Coatings

NASA Astrophysics Data System (ADS)

Anwaar, Aleem; Wei, Lianglinag; Guo, Qian; Zhang, Baopeng; Guo, Hongbo

2017-12-01

Plasma spray-physical vapor deposition (PS-PVD) is an emerging coating technique that can produce columnar thermal barrier coatings from vapor phase. Feedstock treatment at the start of its trajectory in the plasma torch nozzle is important for such vapor-phase deposition. This study describes the effects of the plasma composition (Ar/He) on the plasma characteristics, plasma-particle interaction, and particle dynamics at different points spatially distributed inside the plasma torch nozzle. The results of calculations show that increasing the fraction of argon in the plasma gas mixture enhances the momentum and heat flow between the plasma and injected feedstock. For the plasma gas combination of 45Ar/45He, the total enthalpy transferred to a representative powder particle inside the plasma torch nozzle is highest ( 9828 kJ/kg). Moreover, due to the properties of the plasma, the contribution of the cylindrical throat, i.e., from the feed injection point (FIP) to the start of divergence (SOD), to the total transferred energy is 69%. The carrier gas flow for different plasma gas mixtures was also investigated by optical emission spectroscopy (OES) measurements of zirconium emissions. Yttria-stabilized zirconia (YSZ) coating microstructures were produced when using selected plasma gas compositions and corresponding carrier gas flows; structural morphologies were found to be in good agreement with OES and theoretical predictions. Quasicolumnar microstructure was obtained with porosity of 15% when applying the plasma composition of 45Ar/45He.

Phase analysis of plasma-sprayed zirconia-yttria coatings

NASA Technical Reports Server (NTRS)

Shankar, N. R.; Berndt, C. C.; Herman, H.

1983-01-01

Phase analysis of plasma-sprayed 8 wt pct-yttria-stabilized zirconia (YSZ) thermal barrier coatings and powders was carried out by X-ray diffraction. Step scanning was used for increased peak resolution. Plasma spraying of the YSZ powder into water or onto a steel substrate to form a coating reduced the cubic and monoclinic phases with a simultaneous increase in the tetragonal phase. Heat treatment of the coating at 1150 C for 10 h in an Ar atmosphere increased the amount of cubic and monoclinic phases. The implications of these transformations on coating performance and integrity are discussed.

Broad-bandwidth Metamaterial Antireflection Coatings for Sub-Millimeter Astronomy and CMB Foreground Removal

NASA Astrophysics Data System (ADS)

McMahon, Jeff

Sub-millimeter observations are crucial for answering questions about star and galaxy formation; understanding galactic dust foregrounds; and for removing these foregrounds to detect the faint signature of inflationary gravitational waves in the polarization of the Cosmic Microwave Background (CMB). Achieving these goals requires improved, broad-band antireflection coated lenses and half-wave plates (HWPs). These optical elements will significantly boost the sensitivity and capability of future sub-millimeter and CMB missions. We propose to develop wide-bandwidth metamaterial antireflection coatings for silicon lenses and sapphire HWPs with 3:1 ratio bandwidth that are scalable across the sub-millimeter band from 300 GHz to 3 THz. This is an extension of our successful work on saw cut metamaterial AR coatings for silicon optics at millimeter wave lengths. These, and the proposed coatings consist of arrays of sub-wavelength scale features cut into optical surfaces that behave like simple dielectrics. We have demonstrated saw cut 3:1 bandwidth coatings on silicon lenses, but these coatings are limited to the millimeter wave band by the limitations of dicing saw machining. The crucial advance needed to extend these broad band coatings throughout the sub-millimeter band is the development of laser cut graded index metamaterial coatings. The proposed work includes developing the capability to fabricate these coatings, optimizing the design of these metamaterials, fabricating and testing prototype lenses and HWPs, and working with the PIPER collaboration to achieve a sub-orbital demonstration of this technology. The proposed work will develop potentially revolutionary new high performance coatings for the sub-millimeter bands, and cary this technology to TRL 7 paving the way for its use in space. We anticipate that there will be a wide range of applications for these coatings on future NASA balloons and satellites.

Nanostructure of and structural defects in a Mo2BC hard coating investigated by transmission electron microscopy and atom probe tomography

NASA Astrophysics Data System (ADS)

Gleich, Stephan; Fager, Hanna; Bolvardi, Hamid; Achenbach, Jan-Ole; Soler, Rafael; Pradeep, Konda Gokuldoss; Schneider, Jochen M.; Dehm, Gerhard; Scheu, Christina

2017-08-01

In this work, the nanostructure of a Mo2BC hard coating was determined by several transmission electron microscopy methods and correlated with the mechanical properties. The coating was deposited on a Si (100) wafer by bipolar pulsed direct current magnetron sputtering from a Mo2BC compound target in Ar at a substrate temperature of 630 °C. Transmission electron microscopy investigations revealed structural features at various length scales: bundles (30 nm to networks of several micrometers) consisting of columnar grains (˜10 nm in diameter), grain boundary regions with a less ordered atomic arrangement, and defects including disordered clusters (˜1.5 nm in diameter) as well as stacking faults within the grains. The most prominent defect with a volume fraction of ˜0.5% is the disordered clusters, which were investigated in detail by electron energy loss spectroscopy and atom probe tomography. The results provide conclusive evidence that Ar is incorporated into the Mo2BC film as disordered Ar-rich Mo-B-C clusters of approximately 1.5 nm in diameter. Hardness values of 28 ± 1 GPa were obtained by nanoindentation tests. The Young's modulus of the Mo2BC coating exhibits a value of 462 ± 9 GPa, which is consistent with ab initio calculations for crystalline and defect free Mo2BC and measurements of combinatorically deposited Mo2BC thin films at a substrate temperature of 900 °C. We conclude that a reduction of the substrate temperature of 270 °C has no significant influence on hardness and Young's modulus of the Mo2BC hard coating, even if its nanostructure exhibits defects.

Electrostatic bonding of thin (approximately 3 mil) 7070 cover glass to Ta2O5 AR-coated thin (approximately 2 mil) silicon wafers and solar cells

NASA Technical Reports Server (NTRS)

Egelkrout, D. W.; Horne, W. E.

1980-01-01

Electrostatic bonding (ESB) of thin (3 mil) Corning 7070 cover glasses to Ta2O5 AR-coated thin (2 mil) silicon wafers and solar cells is investigated. An experimental program was conducted to establish the effects of variations in pressure, voltage, temperature, time, Ta2O5 thickness, and various prebond glass treatments. Flat wafers without contact grids were used to study the basic effects for bonding to semiconductor surfaces typical of solar cells. Solar cells with three different grid patterns were used to determine additional requirements caused by the raised metallic contacts.

NiFe2O4 Spinel Protection Coating for High-Temperature Solid Oxide Fuel Cell Interconnect Application

NASA Astrophysics Data System (ADS)

Irankhah, Reza; Raissi, Babak; Maghsoudipour, Amir; Irankhah, Abdullah; Ghashghai, Sasan

2016-04-01

In the present study, Ni-Fe spinel powder was synthesized via a solid state reaction. In the next step, the electrophoretic deposition (EPD) method was used to apply the NiFe2O4 spinel, as an oxidation-resistant layer, on a commercially available stainless steel (SUS 430) in a potential range of 100 to 300 V. Microscopic studies of the deposited layers showed that crack-free NiFe2O4 films were obtained at 100 V. The coated and uncoated samples were then pre-sintered in air and 5% H2 bal Ar atmospheres at 900 °C for 3 h followed by cyclic oxidation at 800 °C for 500 h. The investigation of the oxidation resistance of the samples using Energy Dispersive Spectroscopy (EDS) revealed that the NiFe2O4 coating acted as an effective barrier against chromium migration into the coating. The oxidation resistance of 5% H2 bal Ar pre-sintered sample was enhanced with an oxidation rate constant ( K P) of 8.9 × 10-15 g2 cm-4 s-1.

Electrical and optical properties of sub-10 nm nickel silicide films for silicon solar cells

NASA Astrophysics Data System (ADS)

Brahmi, Hatem; Ravipati, Srikanth; Yarali, Milad; Shervin, Shahab; Wang, Weijie; Ryou, Jae-Hyun; Mavrokefalos, Anastassios

2017-01-01

Highly conductive and transparent films of ultra-thin p-type nickel silicide films have been prepared by RF magnetron sputtering of nickel on silicon substrates followed by rapid thermal annealing in an inert environment in the temperature range 400-600 °C. The films are uniform throughout the wafer with thicknesses in the range of 3-6 nm. The electrical and optical properties are presented for nickel silicide films with varying thickness. The Drude-Lorentz model and Fresnel equations were used to calculate the dielectric properties, sheet resistance, absorption and transmission of the films. These ultrathin nickel silicide films have excellent optoelectronic properties for p-type contacts with optical transparencies up to 80% and sheet resistance as low as ~0.15 µΩ cm. Furthermore, it was shown that the use of a simple anti-reflection (AR) coating can recover most of the reflected light approaching the values of a standard Si solar cell with the same AR coating. Overall, the combination of ultra-low thickness, high transmittance, low sheet resistance and ability to recover the reflected light by utilizing standard AR coating makes them ideal for utilization in silicon based photovoltaic technologies as a p-type transparent conductor.

The effect of SEM imaging on the Ar/Ar system in feldspars

NASA Astrophysics Data System (ADS)

Flude, S.; Sherlock, S.; Lee, M.; Kelley, S. P.

2010-12-01

Complex microtextures form in K-feldspar crystals as they cool and are affected by deuteric alteration. This complex structure is the cause of variable closure temperatures for Ar-Ar, a phenomenon which has been utilized in multi domain diffusion (MDD) modelling to recover thermal histories [1]. However, there has been substantial controversy regarding the precise interaction between feldspar microtextures and Ar-diffusion [2,3]. A number of studies have addressed this issue using coupled SEM imaging and Ar/Ar UV laser ablation microprobe (UV-LAMP) analysis on the same sample, to enable direct comparison of microtextures with Ar/Ar age data [4]. Here we have tested the idea that SEM work may affect Ar/Ar ages, leading to inaccurate results in subsequent Ar/Ar analyses. Three splits of alkali feldspar from the Dartmoor Granite in SW England were selected for Ar/Ar UV-LAMP analysis. Split 1 (“control”) was prepared as a polished thick section for Ar/Ar analysis. Split 2 (“SEM”) was prepared as a polished thick section, was chemically-mechanically polished with colloidal silica and underwent SEM imaging (uncoated) and focussed ion beam (FIB) milling (gold coated); electron beam damage in the SEM was maximised by leaving the sample at high magnification for eight minutes. Split 3 (“Etch”) is a cleavage fragment that was etched with HF vapour and underwent low to moderate magnification SEM imaging. The control split gave a range of laser-spot ages consistent with the expected cooling age of the granite and high yields of radiogenic 40Ar* (>90%). The area of the “SEM” split that experienced significant electron beam damage gave younger than expected ages and 40Ar* yields as low as 57%. These are interpreted as a combination of implantation of atmospheric Ar and local redistribution of K within the sample. The area of “SEM” that underwent FIB milling gave ages and 40Ar* yields comparable to the control split, suggesting that the Au-coat minimises FIB damage and that colloidal-polishing and low-magnification SEM imaging do not affect the Ar/Ar system. The “Etch” split gave younger than expected ages and 40Ar* yields as low as 58%, suggesting that HF etching also disrupts the Ar/Ar system. These results suggest that SEM techniques involving intense electron bombardment of an uncoated sample, such as charge contrast imaging and electron backscatter diffraction (EBSD), may disrupt the Ar/Ar system in the sample, leading to spurious results. Etching samples with HF, as is often done for routine Ar/Ar preparation of volcanic phenocrysts, introduces atmospheric Ar and may result in differential loss or gain of K and Ar isotopes, leading to spurious results. References [1] Lovera and Richter, 1989, J. Geophys. Res. 94, 17917-17935. [2] Parsons. et al., 1999, Cont. Min. Pet. 136, 92-110. [3] Mark et al., 2008, Geochim. Cosmochim. Acta, 72 2695-2710. [4] Reddy et al., 2001, Cont. Min. Pet., 141 186-200.

Characterization of argon dielectric barrier discharges applied to ethyl lactate plasma polymerization

NASA Astrophysics Data System (ADS)

Laurent, Morgane; Desjardins, Edouard; Meichelboeck, Maximilian; Naudé, Nicolas; Stafford, Luc; Gherardi, Nicolas; Laroche, Gaétan

2017-11-01

The influence of the input voltage frequency (35 and 150 kHz), interelectrode gap (1 and 2 mm) and precursor concentration (250, 350, and 450 ppm) on the electron temperature (T e), number density of metastable Ar atoms (n(Ar m )), and discharge current density (proportional to the electron density ne) is studied in an argon-ethyl lactate dielectric barrier discharge (DBD). An argon-ammonia Penning mixture is also considered as reference. These results are correlated to the chemistry (XPS, IR) and topography (AFM) of the ethyl-lactate-based plasma polymer coatings. Low T e values from 0.3 to 0.5 eV were obtained for all discharges. This observation, in addition to resemblances with the Ar-NH3 mixture, suggested that the ionization kinetics of ethyl lactate-based discharges is driven by Penning reactions. Among the investigated parameters, the dissipated power obtained through changes of the excitation frequency had the largest impact on both the coatings properties and the discharge behavior.

Status of diffused junction p+n InP solar cells for space applications

NASA Technical Reports Server (NTRS)

Faur, Mircea; Goradia, C.; Faur, Maria; Fatemi, N. S.; Jenkins, P. P.; Flood, D. J.; Brinker, D. J.; Wilt, D. M.; Bailey, S.; Goradia, M.

1994-01-01

Recently, we have succeeded in fabricating diffused junction p(sup +)n(Cd,S) InP solar cells with measured AMO, 25 C open circuit voltage (V(sub OC)) of 887.6 mV, which, to the best of our knowledge, is higher than previously reported V(sub OC) values for any InP homojunction solar cells. The experiment-based projected achievable efficiency of these cells using LEC grown substrates is 21.3 percent. The maximum AMO, 25 C internal losses due to date on bare cells is, however, only 13.2 percent. This is because of large external and internal losses due to non-optimized front grid design, antireflection (AR) coating and emitter thickness. This paper summarizes recent advances in the technology of fabrication of p(sup +)n InP diffused structures and solar cells, resulted from a study undertaken in an effort to increase the cell efficiency. The topics discussed in this paper include advances in: (1) the formation on thin p(sup +) InP:Cd emitter layers, (2) electroplated front contacts, (3) surface passivation and (4) the design of a new native oxide/Al2O3/MgF2 tree layer AR coating using a chemically-grown P-rich passivating oxide as a first layer. Based on the high radiation resistance and the excellent post-irradiation annealing and recovery demonstrated in the early tests done to date, as well as the projected high efficiency and low-cost high-volume fabricability, these cells show a very good potential for space photovoltaic applications.

Status of diffused junction p+n InP solar cells for space applications

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

Faur, M.; Goradia, C.; Faur, M.

1994-09-01

Recently, the authors have succeeded in fabricating diffused junction p{sup +}n(Cd,S) InP solar cells with measured AMO, 25 C open circuit voltage (V{sub OC}) of 887.6 mV, which, to the best of their knowledge, is higher than previously reported V{sub OC} values for any InP homojunction solar cells. The experiment-based projected achievable efficiency of these cells using LEC grown substrates is 21.3 percent. The maximum AMO, 25 C internal losses due to date on bare cells is, however, only 13.2 percent. This is because of large external and internal losses due to non-optimized front grid design, antireflection (AR) coating andmore » emitter thickness. This paper summarizes recent advances in the technology of fabrication of p{sup +}n InP diffused structures and solar cells, resulted from a study undertaken in an effort to increase the cell efficiency. The topics discussed in this paper include advances in: (1) the formation on thin p{sup +} InP:Cd emitter layers, (2) electroplated front contacts, (3) surface passivation and (4) the design of a new native oxide/Al2O3/MgF2 tree layer AR coating using a chemically-grown P-rich passivating oxide as a first layer. Based on the high radiation resistance and the excellent post-irradiation annealing and recovery demonstrated in the early tests done to date, as well as the projected high efficiency and low-cost high-volume fabricability, these cells show a very good potential for space photovoltaic applications.« less

Al-Mn CVD-FBR coating on P92 steel as protection against steam oxidation at 650 °C: TGA-MS study

NASA Astrophysics Data System (ADS)

Castañeda, S. I.; Pérez, F. J.

2018-02-01

The initial stages oxidation of the P92 ferritic/martensitic steel with and without Al-Mn coating at 650 °C in Ar+40%H2O for 240 h were investigated by mass spectrometry (MS) and thermogravimetric analysis (TGA). TGA-MS measurements were conducted in a closed steam loop. An Al-Mn coating was deposited on P92 steel at 580 °C for 2 h by chemical vapour deposition in a fluidized bed reactor (CVD-FBR). The coating as-deposited was treated in the same reactor at 700 °C in Ar for 2h, in order to produce aluminide phases that form the protective alumina layer (Al2O3) during oxidation. MS measurements at 650 °C of the Al-Mn/P92 sample for 200 h indicated the presence of (Al-Mn-Cr-Fe-O) volatile species of small intensity. Uncoated P92 steel oxidized under the same steam oxidation conditions emitted greater intensities of volatile species of Cr, Fe and Mo in comparison with intensities from coated steel. TGA measurements verified that the mass gained by the coated sample was up to 300 times lower than for uncoated P92 steel. The morphology, composition and structure of samples by Scanning Electron Microscopy SEM, Backscattered Electron (BSE) detection, X-ray Energy Dispersive Spectrometry (EDAX) and X-ray Diffraction (XRD) are described.

Dye surface coating enables visible light activation of TiO2 nanoparticles leading to degradation of neighboring biological structures.

PubMed

Blatnik, Jay; Luebke, Lanette; Simonet, Stephanie; Nelson, Megan; Price, Race; Leek, Rachael; Zeng, Leyong; Wu, Aiguo; Brown, Eric

2012-02-01

Biologically and chemically modified nanoparticles are gaining much attention as a new tool in cancer detection and treatment. Herein, we demonstrate that an alizarin red S (ARS) dye coating on TiO2 nanoparticles enables visible light activation of the nanoparticles leading to degradation of neighboring biological structures through localized production of reactive oxygen species. Successful coating of nanoparticles with dye is demonstrated through sedimentation, spectrophotometry, and gel electrophoresis techniques. Using gel electrophoresis, we demonstrate that visible light activation of dye-TiO2 nanoparticles leads to degradation of plasmid DNA in vitro. Alterations in integrity and distribution of nuclear membrane associated proteins were detected via fluorescence confocal microscopy in HeLa cells exposed to perinuclear localized ARS-TiO2 nanoparticles that were photoactivated with visible light. This study expands upon previous studies that indicated dye coatings on TiO2 nanoparticles can serve to enhance imaging, by clearly showing that dye coatings on TiO2 nanoparticles can also enhance the photoreactivity of TiO2 nanoparticles by allowing visible light activation. The findings of our study suggest a therapeutic application of dye-coated TiO2 nanoparticles in cancer research; however, at the same time they may reveal limitations on the use of dye assisted visualization of TiO2 nanoparticles in live-cell imaging.

Development of a multi-variate calibration approach for quantitative analysis of oxidation resistant Mo-Si-B coatings using laser ablation inductively coupled plasma mass spectrometry

NASA Astrophysics Data System (ADS)

Cakara, Anja; Bonta, Maximilian; Riedl, Helmut; Mayrhofer, Paul H.; Limbeck, Andreas

2016-06-01

Nowadays, for the production of oxidation protection coatings in ultrahigh temperature environments, alloys of Mo-Si-B are employed. The properties of the material, mainly the oxidation resistance, are strongly influenced by the Si to B ratio; thus reliable analytical methods are needed to assure exact determination of the material composition for the respective applications. For analysis of such coatings, laser ablation inductively coupled mass spectrometry (LA-ICP-MS) has been reported as a versatile method with no specific requirements on the nature of the sample. However, matrix effects represent the main limitation of laser-based solid sampling techniques and usually the use of matrix-matched standards for quantitative analysis is required. In this work, LA-ICP-MS analysis of samples with known composition and varying Mo, Si and B content was carried out. Between known analyte concentrations and derived LA-ICP-MS signal intensities no linear correlation could be found. In order to allow quantitative analysis independent of matrix effects, a multiple linear regression model was developed. Besides the three target analytes also the signals of possible argides (40Ar36Ar and 98Mo40Ar) as well as detected impurities of the Mo-Si-B coatings (108Pd) were considered. Applicability of the model to unknown samples was confirmed using external validation. Relative deviations from the values determined using conventional liquid analysis after sample digestion between 5 and 10% for the main components Mo and Si were observed.

Damage threshold dependence of optical coatings on substrate materials

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

Zhouling, W.; Zhenxiu, F.

1996-04-01

Damage threshold dependence on substrate materials was investigated for TiO2, ZrO2, SiO2, MgF2, ZnS, and single and TiO2/SiO2 multilayers. The results show that the damage threshold increases with increasing substrate thermal conductivity for single layers and AR coatings and remains the same for HR coatings. With the help of localized absorption measurement and in-situ damage process analysis, these phenomena were well correlated with local absorption-initiated thermal damage mechanism.

Fiber link design for the NASA-NSF extreme precision Doppler spectrograph concept "WISDOM"

NASA Astrophysics Data System (ADS)

Fżrész, Gábor; Pawluczyk, Rafal; Fournier, Paul; Simcoe, Robert; Woods, Deborah F.

2016-08-01

We describe the design of the fiber-optic coupling and light transfer system of the WISDOM (WIYN Spectrograph for DOppler Monitoring) instrument. As a next-generation Precision Radial Velocity (PRV) spectrometer, WISDOM incorporates lessons learned from HARPS about thermal, pressure, and gravity control, but also takes new measures to stabilize the spectrograph illumination, a subject that has been overlooked until recently. While fiber optic links provide more even illumination than a conventional slit, careful engineering of the interface is required to realize their full potential. Conventional round fiber core geometries have been used successfully in conjunction with optical double scramblers, but such systems still retain a memory of the input illumination that is visible in systems seeking sub-m/s PRV precision. Noncircular fibers, along with advanced optical scramblers, and careful optimization of the spectrograph optical system itself are therefore necessary to study Earth-sized planets. For WISDOM, we have developed such a state-of-the-art fiber link concept. Its design is driven primarily by PRV requirements, but it also manages to preserve high overall throughput. Light from the telescope is coupled into a set of six, 32 μm diameter octagonal core fibers, as high resolution is achieved via pupil slicing. The low-OH, step index, fused silica, FBPI-type fibers are custom designed for their numerical aperture that matches the convergence of the feeding beam and thus minimizes focal ratio degradation at the output. Given the demanding environment at the telescope the fiber end tips are mounted in a custom fused silica holder, providing a perfect thermal match. We used a novel process, chemically assisted photo etching, to manufacture this glass fiber holder. A single ball-lens scrambler is inserted into the 25m long fibers. Employing an anti-reflection (AR) coated, high index, cubic-zirconia ball lens the alignment of the scrambler components are straightforward, as the fiber end tips (also AR coated) by design touch the ball lens and thus eliminate spacing tolerances. A clever and simple opto-mechanical design and assembly process assures micron-level self-alignment, yielding a 87% throughput and a scrambling gain of >20,000. To mitigate modal noise the individual fibers then subsequently combined into a pair of rectangular fibers, providing a much larger modal area thanks to the 34x106 micron diameter. To minimize slit height, and thus better utilize detector area, the octagonal cores are brought very close together in this transition. The two outer fibers are side polished at one side, into a D-shaped cladding, while the central fiber has a dual side polish. These tapered, side-flattening operations are executed with precise alignment to the octagonal core. Thus the cores of the 3 fibers are brought together and aligned within few microns of each other before spliced onto the rectangular fiber. Overall throughput kept high and FRD at bay by careful management of fiber mounting, vacuum feed-through, application of efficient AR coatings, and implementation of thermal breaks that allow for independent expansion of the fibers and the protective tubing.

Thermal Lens Measurement in Diode-Pumped Nd:YAG Zig-Zag Slab

NASA Technical Reports Server (NTRS)

Smoak, M. C.; Kay, R. B.; Coyle, D. B.; Hopf, D.

1998-01-01

A major advantage that solid state zig-zag slab lasers have over conventional rod-based designs is that a much weaker thermal lens is produced in the slab when side-pumped with Quasi-CW laser diode arrays, particularly if the pump radiation is kept well away from the Brewster-cut ends. This paper reports on a rather strong thermal lens produced when diode pump radiation is collimated into a narrow portion of the zig-zag slab. The collimation of multi-bar pump packages to increase brightness and improve overlap is a direct consequence of designs which seek to maximize performance and efficiency. Our slab design employed a 8.1 cm x 2.5 mm x 5 mm slab with opposing Brewster end faces. It was pumped through the 2.5 mm direction by seven laser diode array packages, each housing four 6OW diode bars, 1 cm in width. The pump face, anti-reflection (AR) coated at 809 nm, was 6.8 cm in width and the 8.1 cm opposing side, high-reflection (HR) coated at 809 nm, reflected the unabsorbed pump beam for a second pass through the slab.

Effect of sol aging time on the anti-reflective properties of silica coatings templated with phosphoric acid

NASA Astrophysics Data System (ADS)

Wen, Wen; Li, Haibin; Chen, Xiaojing; Chang, Chengkang

Silica anti-reflective coatings have been prepared by a sol-gel dip-coating process using the sol containing phosphoric acid as a pore-forming template. The effect of the aging time of the sol on the anti-reflective properties has been investigated. The surface topography of the silica AR coatings has been characterized. With increasing sol aging time, more over-sized pores larger than 100 nm are formed in the silica coatings. These could act as scattering centers, scattering visible light and thereby lowering transmittance. The optimal aging time was identified as 1 day, and the corresponding silica coatings showed a maximum transmittance of 99.2%, representing an 8% increase compared to the bare glass substrate.

Self-assembled nanolaminate coatings (SV)

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

Fan, H.

2012-03-01

Sandia National Laboratories (Sandia) and Lockheed Martin Aeronautics (LM Aero) are collaborating to develop affordable, self-assembled, nanocomposite coatings and associated fabrication processes that will be tailored to Lockheed Martin product requirements. The purpose of this project is to develop a family of self-assembled coatings with properties tailored to specific performance requirements, such as antireflective (AR) optics, using Sandia-developed self-assembled techniques. The project met its objectives by development of a simple and economic self-assembly processes to fabricate multifunctional coatings. Specifically, materials, functionalization methods, and associated coating processes for single layer and multiple layers coatings have been developed to accomplish high reflectivemore » coatings, hydrophobic coatings, and anti-reflective coatings. Associated modeling and simulations have been developed to guide the coating designs for optimum optical performance. The accomplishments result in significant advantages of reduced costs, increased manufacturing freedom/producibility, improved logistics, and the incorporation of new technology solutions not possible with conventional technologies. These self-assembled coatings with tailored properties will significantly address LMC's needs and give LMC a significant competitive lead in new engineered materials. This work complements SNL's LDRD and BES programs aimed at developing multifunctional nanomaterials for microelectronics and optics as well as structure/property investigations of self-assembled nanomaterials. In addition, this project will provide SNL with new opportunities to develop and apply self-assembled nanocomposite optical coatings for use in the wavelength ranges of 3-5 and 8-12 micrometers, ranges of vital importance to military-based sensors and weapons. The SANC technologies will be applied to multiple programs within the LM Company including the F-35, F-22, ADP (Future Strike Bomber, UAV, UCAV, etc.). The SANC technologies will establish LMA and related US manufacturing capability for commercial and military applications therefore reducing reliance on off-shore development and production of related critical technologies. If these technologies are successfully licensed, production of these coatings in manufactory will create significant technical employment opportunities.« less

Design considerations for λ ˜ 3.0- to 3.5-μm-emitting quantum cascade lasers on metamorphic buffer layers

NASA Astrophysics Data System (ADS)

Rajeev, Ayushi; Sigler, Chris; Earles, Tom; Flores, Yuri V.; Mawst, Luke J.; Botez, Dan

2018-01-01

Quantum cascade lasers (QCLs) that employ metamorphic buffer layers as substrates of variable lattice constant have been designed for emission in the 3.0- to 3.5-μm wavelength range. Theoretical analysis of the active-region (AR) energy band structure, while using an 8-band k•p model, reveals that one can achieve both effective carrier-leakage suppression as well as fast carrier extraction in QCL structures of relatively low strain. Significantly lower indium-content quantum wells (QWs) can be employed for the AR compared to QWs employed for conventional short-wavelength QCL structures grown on InP, which, in turn, is expected to eliminate carrier leakage to indirect-gap valleys (X, L). An analysis of thermo-optical characteristics for the complete device design indicates that high-Al-content AlInAs cladding layers are more effective for both optical confinement and thermal dissipation than InGaP cladding layers. An electroluminescence-spectrum full-width half-maximum linewidth of 54.6 meV is estimated from interface roughness scattering and, by considering both inelastic and elastic scattering, the threshold-current density for 3.39-μm-emitting, 3-mm-long back-facet-coated QCLs is projected to be 1.40 kA/cm2.

A continuously self regenerating high-flux neutron-generator facility

NASA Astrophysics Data System (ADS)

Rogers, A. M.; Becker, T. A.; Bernstein, L. A.; van Bibber, K.; Bleuel, D. L.; Chen, A. X.; Daub, B. H.; Goldblum, B. L.; Firestone, R. B.; Leung, K.-N.; Renne, P. R.; Waltz, C.

2013-10-01

A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being constructed at UC Berkeley. The current generator, designed around two RF-driven multicusp deuterium ion sources, is capable of producing a neutron output of >1011 n/s. A specially designed titanium-coated copper target located between the ion sources accelerates D+ ions up to 150 keV, generating 2.45 MeV neutrons through the d(d,3He)n fusion reaction. Deuterium in the target is self loaded and regenerating through ion implantation, enabling stable and continuous long-term operation. The proposed science program is focused on pioneering advances in the 40Ar/39Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science research including statistical model studies of radiative-strength functions and level densities, and education. An overview of the facility and its unique capabilities as well as first measurements from the HFNG commissioning will be presented. Work supported by NSF Grant No. EAR-0960138, U.S. DOE LBL Contract No. DE-AC02-05CH11231, and U.S. DOE LLNL Contract No. DE-AC52-07NA27344.

Quantitative image analysis for evaluating the abrasion resistance of nanoporous silica films on glass

PubMed Central

Nielsen, Karsten H.; Karlsson, Stefan; Limbach, Rene; Wondraczek, Lothar

2015-01-01

The abrasion resistance of coated glass surfaces is an important parameter for judging lifetime performance, but practical testing procedures remain overly simplistic and do often not allow for direct conclusions on real-world degradation. Here, we combine quantitative two-dimensional image analysis and mechanical abrasion into a facile tool for probing the abrasion resistance of anti-reflective (AR) coatings. We determine variations in the average coated area, during and after controlled abrasion. Through comparison with other experimental techniques, we show that this method provides a practical, rapid and versatile tool for the evaluation of the abrasion resistance of sol-gel-derived thin films on glass. The method yields informative data, which correlates with measurements of diffuse reflectance and is further supported by qualitative investigations through scanning electron microscopy. In particular, the method directly addresses degradation of coating performance, i.e., the gradual areal loss of antireflective functionality. As an exemplary subject, we studied the abrasion resistance of state-of-the-art nanoporous SiO2 thin films which were derived from 5–6 wt% aqueous solutions of potassium silicates, or from colloidal suspensions of SiO2 nanoparticles. It is shown how abrasion resistance is governed by coating density and film adhesion, defining the trade-off between optimal AR performance and acceptable mechanical performance. PMID:26656260

[Study on the preparation and properties of novel silica microporous antireflective coating by sol-gel process].

PubMed

Shang, Meng-Ying; Cao, Lin-Hong; Liu, Miao; Luo, Xuan; Ren, Hong-Bo; Ye, Xin; Tang, Yong-Jian; Jiang, Xiao-Dong

2013-04-01

Silica sol was prepared by acid catalyzed sol-gel process using tetraethylorthosilicate (TEOS) as precursor and dimethyldietoxysilane (DDS) as pore-forming agent. A novel kind of monolayer microporous silica anti-reflective (AR) coating was obtained on K9 glass substrate by dip-coating technique and then heat treated at 500 degrees C. The effects of different DDS/TEOS molar ratios on refractive index, transmittance and hardness were investigated. A positive correlation was found between the transmittance and the DDS/TEOS molar ratio due to the increasing porosity. The maximum transmittance can reach 99.7% with the molar ratio of DDS/TEOS rising to 1 : 1. Meanwhile, the refractive index was found quite close to the ideal value 1.22. Nevertheless, higher molar ratio will lead to a bad film-forming property. On the other hand, the hardness of the coatings decreased with the DDS increasing but still remained more than 2 h when the transmittance reached highest. Besides, these coatings exhibit a well abrasion-resistance and excellent adhesivity. The maximum transmittance was only dropped by 0.071% and 0.112% after abrasion for 500 and 1 000 times respectively. Accelerated corrosion tests indicated that the transmittance of traditional coatings rapidly fell down to the substrate level (-92%) after immersion for 5 min, while the transmittance of our novel coating almost linearly decreased and was kept 93.2% after 56 min. In other words, the environment-resistance of our novel silica AR coating is ten times higher than that of traditional ones. The promotions of the coating performances benefit from its micropore structure (-0. 4 nm) with which water molecule can be effectively prevented. With its high transmittance, good mechanical properties and high environment-resistance, this kind of novel coating has a potential application in the field of solar glass modification to improve its anti-reflective properties.

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

DOEpatents

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-01-01

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Lapped substrate for enhanced backsurface reflectivity in a thermophotovoltaic energy conversion system

DOEpatents

Baldasaro, Paul F; Brown, Edward J; Charache, Greg W; DePoy, David M

2000-09-05

A method for fabricating a thermophotovoltaic energy conversion cell including a thin semiconductor wafer substrate (10) having a thickness (.beta.) calculated to decrease the free carrier absorption on a heavily doped substrate; wherein the top surface of the semiconductor wafer substrate is provided with a thermophotovoltaic device (11), a metallized grid (12) and optionally an antireflective (AR) overcoating; and, the bottom surface (10') of the semiconductor wafer substrate (10) is provided with a highly reflecting coating which may comprise a metal coating (14) or a combined dielectric/metal coating (17).

Nitrate affects sensu-stricto germination of after-ripened Sisymbrium officinale seeds by modifying expression of SoNCED5, SoCYP707A2 and SoGA3ox2 genes.

PubMed

Carrillo-Barral, Néstor; Matilla, Angel J; Rodríguez-Gacio, María del Carmen; Iglesias-Fernández, Raquel

2014-03-01

The influence of nitrate upon the germination of Sisymbrium officinale seeds is not entirely controlled by after-ripening (AR), a process clearly influenced by nitrate. Recently, we have reported that nitrate affects sensu-stricto germination of non-AR (AR0) seeds by modifying the expression of crucial genes involved in the metabolism of GA and ABA. In this study, we demonstrate that nitrate affects also the germination of AR seeds because: (i) the AR negatively alters the ABA sensitivity being the seed more ABA-sensible as the AR is farthest from optimal (AR0 and AR20 versus AR7); in the presence of diniconazole (DZ), a competitive inhibitor of ABA 8'-hydroxylase, testa rupture is affected while the endosperm rupture is not. (ii) AR7 seed-coat rupture is not inhibited by paclobutrazol (PBZ) suggesting that nitrate can act by a mechanism GA-independent. (iii) The germination process is accelerated by nitrate, most probably by the increase in the expression of SoNCED5, SoCYP707A2 and SoGA3ox2 genes. Taken together, these and previous results demonstrate that nitrate promotes germination of AR and non-AR seeds through transcriptional changes of different genes involved in ABA and GA metabolism. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The synthesis and application of fine particles for coatings and composites

NASA Astrophysics Data System (ADS)

Stephenson, Richard Charles

A variety of coating methods are presented for producing titanium and zirconium oxide coatings on spherical alpha-alumina substrates. Some methods did not completely coat the alumina substrate leaving surface areas exposed. Techniques such as surface modifications with PDVB and 4-VP did produce coatings of metal oxides of very high quality. The best metal oxide coatings are produced from pre-treatment of the alumina microspheres followed by the acid catalyzed hydrolysis of the metal tetra-alkoxides. Methods to investigate converting titanium oxide and zirconium oxide coated alumina microspheres to the corresponding metal carbide coated alumina microspheres have been done. The methods involving direct reduction of the metal oxides by methane and methane-hydrogen gas proved inefficient in producing high quality metal carbide coatings. It is evident higher processing temperatures are required to achieve good metal carbide yield by these methods. Metal oxide coated products carbided by ART (Buffalo, NY) proved the carbiding can be accomplished at higher temperatures and with a different carburizing gas. In addition to the ART carbiding method, the magnesium thermite reaction is a promising method in converting metal oxides to metal carbides at much lower temperatures and shorter processing times. The electrophoretic deposition of Bi2Sr2CaCu 2O8 powder was in ethanol. Of critical consequence were the design of the cathode geometry and the arrangement of the electrodes so that all faces and edges of the silver anode were coated simultaneously. This was achieved by shaping the platinum cathode into a configuration that allowed the silver tape to be completely surrounded by the platinum. The electrophoretic cell was set up to keep the electrodes stationary thereby maintaining a constant distance from the cathode and anode (3 mm). The relationship between deposition time and coating thickness was determined for various powder loadings for a given electric field strength (62 V). For low powder loadings (10 and 20 g/L), the thickness of the coating increases with increasing deposition time (6, 12, and 24 hours). At a powder loading of 30 g/L, the thickness of the BSCCO layer decreases from a deposition time of 6 to 12 hours. At 24 hours, the layer thickness increases. Very high powder loadings (40 g/L) showed a linear decrease in the BSCCO layer thickness with increasing deposition time. Analysis by XRD showed the EPD superconductor exhibited preferential orientation on the silver tape. The degree of orientation was related to the layer thickness and hence the deposition times. Thermal treatment at 800°C in 90% Ar-10% O2 improved the orientation effects. A marked improvement in the surface texture was also observed by SEM. Carbon nanotubes were synthesized via Fe catalysis in an aerosol column in the presence of Ar, CO, and H2 gas. Fe particles were generated by the thermal decarbonylation of Fe(CO)5. Multiwalled and single-walled carbon nanotubes were grown from the decomposition of CO gas on the forming Fe particles. Optimal conditions were determined for producing high yields of single-walled nanotubes. A growth theory is proposed based on the results. (Abstract shortened by UMI.)

Buried nanoantenna arrays: versatile antireflection coating.

PubMed

Kabiri, Ali; Girgis, Emad; Capasso, Federico

2013-01-01

Reflection is usually a detrimental phenomenon in many applications such as flat-panel-displays, solar cells, photodetectors, infrared sensors, and lenses. Thus far, to control and suppress the reflection from a substrate, numerous techniques including dielectric interference coatings, surface texturing, adiabatic index matching, and scattering from plasmonic nanoparticles have been investigated. A new technique is demonstrated to manage and suppress reflection from lossless and lossy substrates. It provides a wider flexibility in design versus previous methods. Reflection from a surface can be suppressed over a narrowband, wideband, or multiband frequency range. The antireflection can be dependent or independent of the incident wave polarization. Moreover, antireflection at a very wide incidence angle can be attained. The reflection from a substrate is controlled by a buried nanoantenna array, a structure composed of (1) a subwavelength metallic array and (2) a dielectric cover layer referred to as a superstrate. The material properties and thickness of the superstrate and nanoantennas' geometry and periodicity control the phase and intensity of the wave circulating inside the superstrate cavity. A minimum reflectance of 0.02% is achieved in various experiments in the mid-infrared from a silicon substrate. The design can be integrated in straightforward way in optical devices. The proposed structure is a versatile AR coating to optically impedance matches any substrate to free space in selected any narrow and broadband spectral response across the entire visible and infrared spectrum.

Self-organized, effective medium black silicon antireflection structures for silicon optics in the mid-infrared

NASA Astrophysics Data System (ADS)

Steglich, Martin; Käsebier, Thomas; Kley, Ernst-Bernhard; Tünnermann, Andreas

2016-09-01

Thanks to its high quality and low cost, silicon is the material of choice for optical devices operating in the mid-infrared (MIR; 2 μm to 6 μm wavelength). Unfortunately in this spectral region, the refractive index is comparably high (about 3.5) and leads to severe reflection losses of about 30% per interface. In this work, we demonstrate that self-organized, statistical Black Silicon structures, fabricated by Inductively Coupled Plasma Reactive Ion Etching (ICP-RIE), can be used to effectively suppress interface reflection. More importantly, it is shown that antireflection can be achieved in an image-preserving, non-scattering way. This enables Black Silicon antireflection structures (ARS) for imaging applications in the MIR. It is demonstrated that specular transmittances of 97% can be easily achieved on both flat and curved substrates, e.g. lenses. Moreover, by a combined optical and morphological analysis of a multitude of different Black Silicon ARS, an effective medium criterion for the examined structures is derived that can also be used as a design rule for maximizing sample transmittance in a desired wavelength range. In addition, we show that the mechanical durability of the structures can be greatly enhanced by coating with hard dielectric materials like diamond-like carbon (DLC), hence enabling practical applications. Finally, the distinct advantages of statistical Black Silicon ARS over conventional AR layer stacks are discussed: simple applicability to topological substrates, absence of thermal stress and cost-effectiveness.

Dual functional porous anti-reflective coatings with a photocatalytic effect based on a single layer system

NASA Astrophysics Data System (ADS)

Jilavi, M. H.; Mousavi, S. H.; Müller, T. S.; de Oliveira, P. W.

2018-05-01

Anti-reflection and photocatalytic properties are desirable for improving the optical properties of electronic devices. We describe a method of fabrication a single-layer, anti-reflective (AR) thin film with an additional photocatalytic property. The layer is deposited on glass substrates by means of a low-cost dip-coating method using a SiO2-TiO2 solution. A comparative study was undertaken to investigate the effects of TiO2 concentrations on the photocatalytic properties of the film and to determine the optimal balance between transmittance and photocatalysis. The average transmittance increases from T = 90.51% to T = 95.46 ± 0.07% for the wavelengths between 380 and 1200 nm. The structural characterization indicated the formation of thin, porous SiO2-TiO2 films with a roughness of less than 7.5 nm. The quality of the samples was evaluated by a complete test program of the mechanical, chemical and accelerated weathering stability. This results open up new possibilities for cost-effective AR coatings for the glass and solar cell industries.

Quartz 9-inch size mask blanks for ArF PSM (Phase Shift Mask)

NASA Astrophysics Data System (ADS)

Harashima, Noriyuki; Isozaki, Tatsuya; Kawanishi, Arata; Kanai, Shuichiro; Kageyama, Kagehiro; Iso, Hiroyuki; Chishima, Tatsuya

2017-07-01

Semiconductor technology nodes are steadily miniaturizing. On the other hand, various efforts have been made to reduce costs, mass production lines have shifted from 200 mmφ of Si wafer to 300 mmφ, and technology development of Si wafer 450 mmφ is also in progress. As a photomask, 6-inch size binary Cr mask has been used for many years, but in recent years, the use of 9-inch binary Cr masks for Proximity Lithography Process in automotive applications, MEMS, packages, etc. has increased, and cost reduction has been taken. Since the miniaturization will progress in the above applications in the future, products corresponding to miniaturization are also desired in 9-inch photomasks. The high grade Cr - binary mask blanks used in proximity exposure process, there is a prospect of being able to use it by ULVAC COATING CORPORATION's tireless research. As further demands for miniaturization, KrF and ArF Lithography Process, which are used for steppers and scanners , there are also a demand for 9-inch size Mask Blanks. In ULVAC COATING CORPORATION, we developed a 9 - inch size KrF PSM mask Blanks prototype in 2016 and proposed a new high grade 9 - inch photomask. This time, we have further investigated and developed 9-inch size ArF PSM Mask Blanks corresponding to ArF Lithography Process, so we report it.

Measurement system to determine the total and angle-resolved light scattering of optical components in the deep-ultraviolet and vacuum-ultraviolet spectral regions

NASA Astrophysics Data System (ADS)

Schröder, Sven; Gliech, Stefan; Duparré, Angela

2005-10-01

An instrumentation for total and angle-resolved scattering (ARS) at 193 and 157 nm has been developed at the Fraunhofer Institute in Jena to meet the severe requirements for scattering analysis of deep- and vacuum-ultraviolet optical components. Extremely low backscattering levels of 10^-6 for the total scattering measurements and more than 9 orders of magnitude dynamic range for ARS have been accomplished. Examples of application extend from the control of at-wavelength scattering losses of superpolished substrates with rms roughness as small as 0.1 nm to the detection of volume material scattering and the study into the scattering of multilayer coatings. In addition, software programs were developed to model the roughness-induced light scattering of substrates and thin-film coatings.

Polarization sensitivity of ordered and random antireflective surface structures in silica and spinel

NASA Astrophysics Data System (ADS)

Frantz, J. A.; Selby, J.; Busse, L. E.; Shaw, L. B.; Aggarwal, I. D.; Sanghera, J. S.

2018-02-01

Both ordered and random anti-reflective surface structures (ARSS) have been shown to increase the transmission of an optical surface to >99.9%. These structures are of great interest as an alternative to traditional thin film anti-reflection (AR) coatings for a variety of reasons. Unlike traditional AR coatings, they are patterned directly into the surface of an optic rather than deposited on its surface and are thus not prone to the delamination under thermal cycling that can occur with thin film coatings. Their laser-induced damage thresholds can also be considerably higher. In addition, they provide AR performance over a larger spectral and angular range. It has been previously demonstrated that random ARSSs in silica are remarkably insensitive to incident polarization, with nearly zero variation in transmittance with respect to polarization of the incident beam at fixed wavelength for angles of incidence up to at least 30°. In this work, we evaluate polarization sensitivity of ARSS as a function of wavelength for both random and ordered ARSS. We demonstrate that ordered ARSS is significantly more sensitive to polarization than random ARSS and explain the reason for this difference. In the case of ordered ARSS, we observe significant differences as a function of wavelength, with the transmittance of s- and p-polarized light diverging near the diffraction edge. We present results for both silica and spinel samples and discuss differences observed for these two sets of samples.

The effects of phase transformation on the structure and mechanical properties of TiSiCN nanocomposite coatings deposited by PECVD method

NASA Astrophysics Data System (ADS)

Abedi, Mohammad; Abdollah-zadeh, Amir; Bestetti, Massimiliano; Vicenzo, Antonello; Serafini, Andrea; Movassagh-Alanagh, Farid

2018-06-01

In the present study, the effects of phase transformations on the structure and mechanical properties of TiSiCN coatings were investigated. TiSiCN nanocomposite coatings were deposited on AISI H13 hot-work tool steel by a pulsed direct current plasma-enhanced chemical vapor deposition process at 350 or 500 °C, using TiCl4 and SiCl4 as the precursors of Ti and Si, respectively, in a CH4/N2/H2/Ar plasma as the source of carbon and nitrogen and reducing environment. Some samples deposited at 350 °C were subsequently annealed at 500 °C under Ar atmosphere. Super hard self-lubricant TiSiCN coatings, having nanocomposite structure consisting of TiCN nanocrystals and amorphous carbon particles embedded in an amorphous SiCNx matrix, formed through spinodal decomposition in the specimens deposited or annealed at 500 °C. In addition, it was revealed that either uncomplete or relatively coarse phase segregation of titanium compounds was achieved during deposition at 350 °C and 500 °C, respectively. On the contrary, by deposition at 350 °C followed by annealing at 500 °C, a finer structure was obtained with a sensible improvement of the mechanical properties of coatings. Accordingly, the main finding of this work is that significant enhancement in key properties of TiSiCN coatings, such as hardness, adhesion and friction coefficient, can be obtained by deposition at low temperature and subsequent annealing at higher temperature, thanks to the formation of a fine grained nanocomposite structure.

Instrument development of the CMB polarization POLARBEAR-2 experiment

NASA Astrophysics Data System (ADS)

Siritanasak, Praween; POLARBEAR Collaboration

2017-06-01

We present the status of the development of the Polarbear-2 (PB-2) and Simons Array experiments. PB-2 is a ground-based Cosmic Microwave Back- ground (CMB) polarization experiment located at the James Ax observatory in the Atacama desert of Northern Chile. The Simons Array will consist of three PB-2 receivers on three Huan Tran-style telescopes, each containing a multi-chroic detector array. The first new Simons Array receiver, Polarbear- 2A(PB-2A), will be deployed in 2017. The PB-2A focal plane consists of 1,897 lenslet-coupled, dual-polarization, sinuous-antenna-coupled pixels operating at 95 and 150 GHz, making a total of 7,588 polarization-sensitive transition edge sensor (TES) bolometers. In the order to cover both frequencies, we developed broadband two layer anti-reflection (AR) coating for 5.345 mm diameter lenslets using two types of epoxy: Stycast2850FT and Stycast1090. We developed a mass production AR coating methodology that can control the uniformity and shape to within 25 μm error from the designed value. The second (PB-2B) and third (PB-2C) receivers will employ similar technologies and will cover 95, 150, 220 and 280 GHz. The Simons Array will survey 80% of the sky with broad frequency coverage and high resolution, making it a powerful tool to constrain the tensor-to-scalar ratio through measurements of primordial B-modes and the sum of the neutrino masses through measurements of B-modes produced by gravitational lensing.

Laser Micromachining Fabrication of THz Components

NASA Technical Reports Server (NTRS)

DrouetdAubigny, C.; Walker, C.; Jones, B.; Groppi, C.; Papapolymerou, J.; Tavenier, C.

2001-01-01

Laser micromachining techniques can be used to fabricate high-quality waveguide structures and quasi-optical components to micrometer accuracies. Successful GHz designs can be directly scaled to THz frequencies. We expect this promising technology to allow the construction of the first fully integrated THz heterodyne imaging arrays. At the University of Arizona, construction of the first laser micromachining system designed for THz waveguide components fabrication has been completed. Once tested and characterized our system will be used to construct prototype THz lx4 focal plane mixer arrays, magic tees, AR coated silicon lenses, local oscillator source phase gratings, filters and more. Our system can micro-machine structures down to a few microns accuracy and up to 6 inches across in a short time. This paper discusses the design and performance of our micromachining system, and illustrates the type, range and performance of components this exciting new technology will make accessible to the THz community.

Development of integral covers on solar cells

NASA Technical Reports Server (NTRS)

Stella, P.; Somberg, H.

1971-01-01

The electron-beam technique for evaporating a dielectric material onto solar cells is investigated. A process has been developed which will provide a highly transparent, low stress, 2 mil thick cover capable of withstanding conventional space type qualification tests including humidity, thermal shock, and thermal cycling. The covers have demonstrated the ability to withstand 10 to the 15th power 1 MeV electrons and UV irradiation with minor darkening. Investigation of the cell AR coating has produced a space qualifiable titanium oxide coating which will give an additional 6% current output over similar silicon oxide coated cells when covered by glass.

Directed Energy Technology Overview

DTIC Science & Technology

2011-06-01

with an AR coating, The primary mirror is zerodur on a 9 point mount incorporating a tuned mass damper.. The secondary, tertiary, and coude optics are...beam conditioning back end section: • A beam expander enlarges the beam and shapes it to fill the active area of a deformable mirror • Because of the...enabling technologies that would make a 100-kW SS laser possible (high power optical coatings, high power gain modules, deformable mirror technology

Demonstration of Antimicrobial Corrosion-Resisting Interior Coating Systems for Military Facilities in Warm, Humid Locations

DTIC Science & Technology

2017-06-01

ER D C/ CE RL T R- 17 -1 9 DoD Corrosion Prevention and Control Program Demonstration of Antimicrobial Corrosion- Resisting Interior ...Demonstration of Antimicrobial Corrosion- Resisting Interior Coating Systems for Military Facilities in Warm, Humid Locations Final Report on...Under Project F10-AR04, “Application of New Corrosion-Resistant Mold Abatement Technologies for Interior Surfaces of Buildings at Fort Polk, LA” ERDC

Low-reflective wire-grid polarizers with absorptive interference overlayers.

PubMed

Suzuki, Motofumi; Takada, Akio; Yamada, Takatoshi; Hayasaka, Takashi; Sasaki, Kouji; Takahashi, Eiji; Kumagai, Seiji

2010-04-30

Wire-grid (WG) polarizers with low reflectivity for visible light have been successfully developed. We theoretically consider the optical properties of simple sandwich structures of absorptive layer/transparent layer (gap layer)/high-reflective mirrors and found that it is possible to develop an antireflection (AR) coating owing to the interference along with the absorption in the absorptive layer. A wide variety of materials can be used for AR coatings by tuning the thicknesses of both the absorptive and the gap layers. This AR concept has been applied to reduce the reflectance of WG polarizers of Al. FeSi(2) as an absorptive layer has been deposited by the glancing angle deposition technique immediately on the top of Al wires covered with a thin SiO(2) layer as a gap layer. For the optimum combination of the thicknesses of FeSi(2) and SiO(2), the reflectance becomes lower than a few per cent, independent of the polarization, whereas the transmission polarization properties remain good. Because low-reflective (LR) WG polarizers are completely composed of inorganic materials, they are useful for applications requiring high-temperature durability such as liquid crystal projection displays.

High Temperature Thermal Stability and Oxidation Resistance of Magnetron-sputtered Homogeneous CrAlON Coatings on 430 Steel

NASA Astrophysics Data System (ADS)

Kayani, A.; Wickey, K. J.; Nandasiri, M. I.; Moore, A.; Garratt, E.; AlFaify, S.; Gao, X.; Smith, R. J.; Buchanan, T. L.; Priyantha, W.; Kopczyk, M.; Gannon, P. E.; Gorokhovsky, V. I.

2009-03-01

The requirements of low cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of steel plates with homogenous coatings of CrAlON (oxynitrides). The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas. Oxygen in these coatings was not intentionally added. Oxygen might have come through contaminated nitrogen gas bottle, leak in the chamber or from the partial pressure of water vapors. Nitrogen was added during the growth process to get oxynitride coating. The Cr/Al composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800° C. The composition of the coated plates and the rate of oxidation were characterized using Rutherford backscattering (RBS) and nuclear reaction analysis (NRA). From our results, we conclude that Al rich coatings are more susceptible to oxidation than Cr rich coatings.

Polarimetric and diffractive evaluation of 3.74 micron pixel-size LCoS in the telecommunications C-band

NASA Astrophysics Data System (ADS)

Wang, Mi; Martínez, Francisco J.; Márquez, Andrés.; Ye, Yabin; Zong, Liangjia; Pascual, Inmaculada; Beléndez, Augusto

2017-08-01

Liquid-crystal on Silicon (LCoS) microdisplays are one of the competing technologies to implement wavelength selective switches (WSS) for optical telecommunications. Last generation LCoS, with more than 4 megapixels, have decreased pixel size to values smaller than 4 microns, what increases interpixel cross-talk effects such as fringing-field. We proceed with an experimental evaluation of a 3.74 micron pixel size parallel-aligned LCoS (PA-LCoS) device. At 1550 nm, for the first time we use time-average Stokes polarimetry to measure the retardance and its flicker magnitude as a function of voltage. We also verify the effect of the antireflection coating when we try to characterize the PA-LCoS out of the designed interval for the AR coating. Some preliminary results for the performance for binary gratings are also given, where the decrease of modulation range with the increase in spatial frequency is shown, together with some residual polarization effects.

Influence of microstructure on hardness of plasma sprayed Al2O3-TiO2-MgO coatings with interface diffusion by heat treatment

NASA Astrophysics Data System (ADS)

Chen, Kunlun; Song, Peng; Li, Chao; Lu, Jiansheng

2017-12-01

The effect of heat treatment on the microstructure and mechanical properties of Al2O3-TiO2 coatings doped with 5 wt% MgO was investigated in this paper. The composite coatings were prepared by atmospheric plasma spraying (APS) and heat treated at 1000 °C for 24 h in Ar. The coatings were analyzed using scanning electron microscopy with electron probe x-ray microanalysis and x-ray diffraction. The hardness was determined using a Vickers hardness test on the as-sprayed coatings and after heat treatment. The results showed that the interface diffusion between the Al-rich and Ti-rich layers resulted in mutual pinning within the coating during the heat treatment. The newly formed MgAl2O4 phase promoted cracking-healing behavior within the coating. We conclude that increase of the hardness of the coatings was mainly caused by the mutual pinning interface and crack healing.

Frictional behavior and adhesion of Ag and Au films applied to aluminum oxide by oxygen-ion assisted Screen Cage Ion Plating (SCIP)

NASA Technical Reports Server (NTRS)

Spalvins, Talivaldis; Sliney, Harold E.

1994-01-01

A modified dc-diode ion plating system, by utilizing a metallic screen cage as a cathode, is introduced for coating nonconductors such as ceramics. Screen cage ion plating (SCIP) is used to apply Ag and Au lubricating films on aluminum oxide surfaces. This process has excellent ability to coat around corners to produce three-dimensional coverage of the substrate. A dramatic increase in adhesion is achieved when plating is performed in a reactive 50 percent O2 - 50 percent Ar glow discharge compared to the adhesion when plating is performed in 100 percent Ar. The presence of oxygen ion assistance contributes to the excellent adhesion as measured in a pull-type adhesion tester. The Ag and Au film adhesion is significantly increased (less than 70MPa) and generally exceeds the cohesion of the substrate such that portions of the alumina are pulled out.

Ink jet assisted metallization for low cost flat plate solar cells

NASA Technical Reports Server (NTRS)

Teng, K. F.; Vest, R. W.

1987-01-01

Computer-controlled ink-jet-assisted metallization of the front surface of solar cells with metalorganic silver inks offers a maskless alternative method to conventional photolithography and screen printing. This method can provide low cost, fine resolution, reduced process complexity, avoidance of degradation of the p-n junction by firing at lower temperature, and uniform line film on rough surface of solar cells. The metallization process involves belt furnace firing and thermal spiking. With multilayer ink jet printing and firing, solar cells of about 5-6 percent efficiency without antireflection (AR) coating can be produced. With a titanium thin-film underlayer as an adhesion promoter, solar cells of average efficiency 8.08 percent without AR coating can be obtained. This efficiency value is approximately equal to that of thin-film solar cells of the same lot. Problems with regard to lower inorganic content of the inks and contact resistance are noted.

Mechanical comparison of a polymer nanocomposite to a ceramic thin-film anti-reflective filter.

PubMed

Druffel, Thad; Geng, Kebin; Grulke, Eric

2006-07-28

Thin-film filters on optical components have been in use for decades and, for those industries utilizing a polymer substrate, the mismatch in mechanical behaviour has caused problems. Surface damage including scratches and cracks induces haze on the optical filter, reducing the transmission of the optical article. An in-mold anti-reflective (AR) filter incorporating 1/4-wavelength thin films based on a polymer nanocomposite is outlined here and compared with a traditional vacuum deposition AR coating. Nanoindentation and nanoscratch techniques are used to evaluate the mechanical properties of the thin films. Scanning electron microscopy (SEM) images of the resulting indentations and scratches are then compared to the force deflection curves to further explain the phenomena. The traditional coatings fractured by brittle mechanisms during testing, increasing the area of failure, whereas the polymer nanocomposite gave ductile failure with less surface damage.

Microscale characterization of metallic coatings for a high strength high conductivity copper alloy

NASA Astrophysics Data System (ADS)

Jain, Piyush

NiCrAlY overlay coatings are being considered by NASA's Glenn Research Center to prevent blanching and reduce thermo-mechanical fatigue of rocket engine combustion chamber liners made of GRCop-84 (Cu-8%Cr-4%Nb) for reusable launch vehicles (RLVs). However, their successful application depends upon their integrity to the GRCop-84 during multiple firings of rocket engines. This study focuses on determining the adhesion of NiCrAlY coatings and their microstructural stability on GRCop-84 as a function of thermal cycling. Specimens were prepared by depositing NiCrAlY top coat on GRCop-84 by vacuum plasma spaying with a thin layer of Cu-26Cr as a bond coat. A thermal cycling rig was built to thermally cycle the NiCrAlY/Cu-26Cr/GRCop-84 specimens from RT to 600°C in an argon environment, with 10 minutes hold at 600°C, and 4 minutes hold at RT. Samples were cut from the coupons in as-received condition (AR), after 100 thermal cycles (TC-100), and after 300 thermal cycles (TC-300) for characterization. A newly developed interfacial microsample testing technique was employed to determine the adhesion of the coatings on GRCop-84, where bowtie shaped microsamples having interfaces normal to the tensile axis were tested. Interfacial microsamples of NiCrAlY/Cu-26Cr/GRCop-84 in all the conditions (AR, TC-100, and TC-300) failed cohesively in the substrate at a UTS of 380+/-5 MPa and their interfaces remained intact. The microstructural characterization revealed that microstructure of the NiCrAlY/Cu-26Cr/GRCop-84 specimens does not degrade as a function of thermal cycling. Constitutive properties of NiCrAlY, Cu-26Cr, and GRCop-84 were measured by testing monolithic samples and were used to build the finite element model (FEM) of the interfacial microsamples. The FE model analyzed the local stress-strain in the interfacial microsamples during the testing and confirmed the strength of the interfaces to be higher than 380+/-5 MPa. Depleted zones, devoid of Cr2Nb particles, were observed in the substrate near the interface, which has been attributed to uncontrolled processing parameters during the coating deposition. The interfacial microsamples containing depleted zones, failed at 335+/-25 MPa in AR condition exhibiting cohesive-adhesive failure, and at 360+/-15 MPa in TC-300 condition exhibiting adhesive failure. All these results suggested that the presence of depleted zone decreases the adhesion of the coating and should be avoided in future coatings deposition. Adhesion of two top coats, NiCrAlY (with the Cu-26Cr bond coat) and the Cu-26Cr (without any bond coat), were found to be lower on the grit blasted GRCop-84 than on the polished GRCop-84. The adhesion of both the top coats on polished GRCop-84 was measured to be 380+/-5 MPa with cohesive failure in the substrate, while the adhesion of NiCrAlY top coat on the grit blasted GRCop-84 was measured to be 142+/-35 MPa with cohesive failure in the Cu-26Cr bond coat, and the adhesion of Cu-26Cr top coat on the grit blasted GRCop-84 was measured to be 360+/-25 MPa with cohesive failure in the Cu-26Cr top coat. The microstructural characterization revealed that the reason of lower strength of top coats on the grit blasted GRCop-84 was the porosity present in the coatings on the grit blasted GRCop-84, while the coatings on the polished GRCop-84 did not have any measurable porosity.

High durability antireflection coatings for silicon and multispectral ZnS

NASA Astrophysics Data System (ADS)

Joseph, Shay; Marcovitch, Orna; Yadin, Ygal; Klaiman, Dror; Koren, Nitzan; Zipin, Hedva

2007-04-01

In the current complex battle field, military platforms are required to operate on land, at sea and in the air in all weather conditions both day and night. In order to achieve such capabilities, advanced electro-optical systems are being constantly developed and improved. These systems such as missile seeker heads, reconnaissance and target acquisition pods and tracking, monitoring and alert systems have external optical components (window or dome) which must remain operational even at extreme environmental conditions. Depending on the intended use of the system, there are a few choices of window and dome materials. Amongst the more common materials one can point out sapphire, ZnS, germanium and silicon. Other materials such as spinel, ALON and yittria may also be considered. Most infrared materials have high indices of refraction and therefore they reflect a large part of radiation. To minimize the reflection and increase the transmission, antireflection (AR) coatings are the most common choice. Since these systems operate at different environments and weather conditions, the coatings must be made durable to withstand these extreme conditions. In cases where the window or dome is made of relatively soft materials such as multispectral ZnS, the coating may also serve as protection for the window or dome. In this work, several antireflection coatings have been designed and manufactured for silicon and multispectral ZnS. The coating materials were chosen to be either oxides or fluorides which are known to have high durability. Ellipsometry measurements were used to characterize the optical constants of the thin films. The effects of the deposition conditions on the optical constants of the deposited thin films and durability of the coatings will be discussed. The coatings were tested according to MIL-STD-810E and were also subjected to rain erosion tests at the University of Dayton Research Institute (UDRI) whirling arm apparatus in which one of the coatings showed no rain drop impact damage at all.

Calcium and Zinc Containing Bactericidal Glass Coatings for Biomedical Metallic Substrates

PubMed Central

Esteban-Tejeda, Leticia; Díaz, Luis A.; Prado, Catuxa; Cabal, Belén; Torrecillas, Ramón; Moya, José S.

2014-01-01

The present work presents new bactericidal coatings, based on two families of non-toxic, antimicrobial glasses belonging to B2O3–SiO2–Na2O–ZnO and SiO2–Na2O–Al2O3–CaO–B2O3 systems. Free of cracking, single layer direct coatings on different biomedical metallic substrates (titanium alloy, Nb, Ta, and stainless steel) have been developed. Thermal expansion mismatch was adjusted by changing glass composition of the glass type, as well as the firing atmosphere (air or Ar) according to the biomedical metallic substrates. Formation of bubbles in some of the glassy coatings has been rationalized considering the reactions that take place at the different metal/coating interfaces. All the obtained coatings were proven to be strongly antibacterial versus Escherichia coli (>4 log). PMID:25056542

Superhydrophobic Copper Surfaces with Anticorrosion Properties Fabricated by Solventless CVD Methods.

PubMed

Vilaró, Ignasi; Yagüe, Jose L; Borrós, Salvador

2017-01-11

Due to continuous miniaturization and increasing number of electrical components in electronics, copper interconnections have become critical for the design of 3D integrated circuits. However, corrosion attack on the copper metal can affect the electronic performance of the material. Superhydrophobic coatings are a commonly used strategy to prevent this undesired effect. In this work, a solventless two-steps process was developed to fabricate superhydrophobic copper surfaces using chemical vapor deposition (CVD) methods. The superhydrophobic state was achieved through the design of a hierarchical structure, combining micro-/nanoscale domains. In the first step, O 2 - and Ar-plasma etchings were performed on the copper substrate to generate microroughness. Afterward, a conformal copolymer, 1H,1H,2H,2H-perfluorodecyl acrylate-ethylene glycol diacrylate [p(PFDA-co-EGDA)], was deposited on top of the metal via initiated CVD (iCVD) to lower the surface energy of the surface. The copolymer topography exhibited a very characteristic and unique nanoworm-like structure. The combination of the nanofeatures of the polymer with the microroughness of the copper led to achievement of the superhydrophobic state. AFM, SEM, and XPS were used to characterize the evolution in topography and chemical composition during the CVD processes. The modified copper showed water contact angles as high as 163° and hysteresis as low as 1°. The coating withstood exposure to aggressive media for extended periods of time. Tafel analysis was used to compare the corrosion rates between bare and modified copper. Results indicated that iCVD-coated copper corrodes 3 orders of magnitude slower than untreated copper. The surface modification process yielded repeatable and robust superhydrophobic coatings with remarkable anticorrosion properties.

Characterization of Carbon-Contaminated B4C-Coated Optics after Chemically Selective Cleaning with Low-Pressure RF Plasma.

PubMed

Moreno Fernández, H; Rogler, D; Sauthier, G; Thomasset, M; Dietsch, R; Carlino, V; Pellegrin, E

2018-01-22

Boron carbide (B 4 C) is one of the few materials that is expected to be most resilient with respect to the extremely high brilliance of the photon beam generated by free electron lasers (FELs) and is thus of considerable interest for optical applications in this field. However, as in the case of many other optics operated at light source facilities, B 4 C-coated optics are subject to ubiquitous carbon contaminations. Carbon contaminations represent a serious issue for the operation of FEL beamlines due to severe reduction of photon flux, beam coherence, creation of destructive interference, and scattering losses. A variety of B 4 C cleaning technologies were developed at different laboratories with varying success. We present a study regarding the low-pressure RF plasma cleaning of carbon contaminated B 4 C test samples via inductively coupled O 2 /Ar, H 2 /Ar, and pure O 2 RF plasma produced following previous studies using the same ibss GV10x downstream plasma source. Results regarding the chemistry, morphology as well as other aspects of the B 4 C optical coating before and after the plasma cleaning are reported. We conclude that among the above plasma processes only plasma based on pure O 2 feedstock gas exhibits the required chemical selectivity for maintaining the integrity of the B 4 C optical coatings.

A facile method for synthesis of well-coated ZnO@graphene core/shell structure by self-assembly of amine-functionalized ZnO and graphene oxide

NASA Astrophysics Data System (ADS)

Zhang, Yunlong; Song, Lixin; Zhang, Yuzhi; Wang, Panpan; Liu, Yangqiao; Wu, Lingnan; Zhang, Tao

2016-06-01

The core/shell structure was formed by GO self-assembled with amine-functionalized commercial ZnO (CZO) and preparative hexagonal ZnO (HZO), respectively. Graphene-coated CZO and HZO were obtained after being reduced in Ar at 500 °C. The mechanism of the coating procedure was investigated by measuring their respective zeta potential values. Our characterizations demonstrate that graphene on HZO has better quality and fewer layers. An obvious band gap decrease of ZnO was observed for coating with graphene. Photoluminescence spectra of ZnO@graphene core/shell composites display the fluorescence quenching property, which indicates its good application prospect in optoelectronics, photocatalytic and other fields.

Nab-paclitaxel/Rituximab-coated Nanoparticle AR160 in Treating Patients With Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

ClinicalTrials.gov

2018-04-17

Aggressive Non-Hodgkin Lymphoma; CD20 Positive; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Small Lymphocytic Lymphoma

Filling high aspect ratio trenches by superconformal chemical vapor deposition: Predictive modeling and experiment

NASA Astrophysics Data System (ADS)

Wang, Wenjiao B.; Abelson, John R.

2014-11-01

Complete filling of a deep recessed structure with a second material is a challenge in many areas of nanotechnology fabrication. A newly discovered superconformal coating method, applicable in chemical vapor deposition systems that utilize a precursor in combination with a co-reactant, can solve this problem. However, filling is a dynamic process in which the trench progressively narrows and the aspect ratio (AR) increases. This reduces species diffusion within the trench and may drive the component partial pressures out of the regime for superconformal coating. We therefore derive two theoretical models that can predict the possibility for filling. First, we recast the diffusion-reaction equation for the case of a sidewall with variable taper angle. This affords a definition of effective AR, which is larger than the nominal AR due to the reduced species transport. We then derive the coating profile, both for superconformal and for conformal coating. The critical (most difficult) step in the filling process occurs when the sidewalls merge at the bottom of the trench to form the V shape. Experimentally, for the Mg(DMADB)2/H2O system and a starting AR = 9, this model predicts that complete filling will not be possible, whereas experimentally we do obtain complete filling. We then hypothesize that glancing-angle, long-range transport of species may be responsible for the better than predicted filling. To account for the variable range of species transport, we construct a ballistic transport model. This incorporates the incident flux from outside the structure, cosine law re-emission from surfaces, and line-of-sight transport between internal surfaces. We cast the transport probability between all positions within the trench into a matrix that represents the redistribution of flux after one cycle of collisions. Matrix manipulation then affords a computationally efficient means to determine the steady-state flux distribution and growth rate for a given taper angle. The ballistic transport model predicts a deeper position for the peak of the super-conformal growth rate than the diffusion-reaction model, and successfully explains the observation of complete filling. These models can be used to predict the behavior of any system given a small set of kinetic coefficients to describe the growth rate.

Specifications of ZnO growth for heterostructure solar cell and PC1D based simulations

PubMed Central

Hussain, Babar; Ebong, Abasifreke

2015-01-01

This data article is related to our recently published article (Hussain et al., in press [1]) where we have proposed a new solar cell model based on n-ZnO as front layer and p-Si as rear region. The ZnO layer will act as an active n-layer as well as antireflection (AR) coating saving considerable processing cost. There are several reports presenting use of ZnO as window/antireflection coating in solar cells (Mansoor et al., 2015; Haq et al., 2014; Hussain et al., 2014; Matsui et al., 2014; Ding et al., 2014 [2], [3], [4], [5], [6]) but, here, we provide data specifically related to simultaneous use of ZnO as n-layer and AR coating. Apart from the information we already published, we provide additional data related to growth of ZnO (with and without Ga incorporation) layers using MOCVD. The data related to PC1D based simulation of internal and external quantum efficiencies with and without antireflection effects of ZnO as well as the effects of doping level in p-Si on current–voltage characteristics have been provided. PMID:26587557

Improvement in Therapeutic Efficacy and Reduction in Cellular Toxicity: Introduction of a Novel Anti-PSMA-Conjugated Hybrid Antiandrogen Nanoparticle.

PubMed

Thangavel, Chellappagounder; Perepelyuk, Maryna; Boopathi, Ettickan; Liu, Yi; Polischak, Steven; Deshpande, Deepak A; Rafiq, Khadija; Dicker, Adam P; Knudsen, Karen E; Shoyele, Sunday A; Den, Robert B

2018-05-07

Second generation antiandrogens have improved overall survival for men with metastatic castrate resistant prostate cancer; however, the antiandrogens result in suppression of androgen receptor (AR) activity in all tissues resulting in dose limiting toxicity. We sought to overcome this limitation through encapsulation in a prostate specific membrane antigen (PSMA)-conjugated nanoparticle. We designed and characterized a novel nanoparticle containing an antiandrogen, enzalutamide. Selectivity and enhanced efficacy was achieved through coating the particle with PSMA. The PSMA-conjugated nanoparticle was internalized selectively in AR expressing prostate cancer cells. It did not elicit an inflammatory effect. The efficacy of enzalutamide was not compromised through insertion into the nanoparticle; in fact, lower systemic drug concentrations of enzalutamide resulted in comparable clinical activity. Normal muscle cells were not impacted by the PSMA-conjugated containing antiandrogen. This approach represents a novel strategy to increase the specificity and effectiveness of antiandrogen treatment for men with castrate resistant prostate cancer. The ability to deliver higher drug concentrations in prostate cancer cells may translate into improved clinical end points including overall survival.

High temperature oxidation resistance of magnetron-sputtered homogeneous CrAlON coatings on 430 steel

NASA Astrophysics Data System (ADS)

Garratt, E.; Wickey, K. J.; Nandasiri, M. I.; Moore, A.; AlFaify, S.; Gao, X.; Kayani, A.; Smith, R. J.; Buchanan, T. L.; Priyantha, W.; Kopczyk, M.; Gannon, P. E.

2009-11-01

The requirements of low cost and high-temperature corrosion resistance for bipolar interconnect plates in solid oxide fuel cell stacks has directed attention to the use of metal plates with oxidation resistant coatings. We have investigated the performance of steel plates with homogenous coatings of CrAlON (oxynitrides). The coatings were deposited using RF magnetron sputtering, with Ar as a sputtering gas. Oxygen in these coatings was not intentionally added. Oxygen might have come through contaminated nitrogen gas bottle, leak in the chamber or from the partial pressure of water vapors. Nitrogen was added during the growth process to get oxynitride coating. The Cr/Al composition ratio in the coatings was varied in a combinatorial approach. The coatings were subsequently annealed in air for up to 25 hours at 800 oC. The composition of the coated plates and the rate of oxidation were characterized using Rutherford backscattering (RBS) and nuclear reaction analysis (NRA). Surface characterization was carried out using Atomic Force Microscopy (AFM) and surfaces of the coatings were found smooth on submicron scale. From our results, we conclude that Al rich coatings are more susceptible to oxidation than Cr rich coatings.

Burner Rig Evaluation of Thermal Barrier Coating Systems for Nickel-Base Alloys

NASA Technical Reports Server (NTRS)

Gedwill, M. A.

1981-01-01

Eight plasma sprayed bond coatings were evaluated for their potential use with ZrO2-Y2O3 thermal barrier coatings (TECs) which are being developed for coal derived fuel fired gas turbines. Longer TBC lives in cyclic burner rig oxidation to 1050 C were achieved with the more oxidation resistant bond coatings. These were Ni-14.1Cr-13.4A1-0.10Ar, Ni-14.1C4-14.4Al-0.16Y, and Ni-15.8Cr-12.8Al-0.36Y on Rene 41. The TBC systems performed best when 0.015-cm thick bond coatings were employed that were sprayed at 20 kW using argon 3.5v/o hydrogen. Cycling had a more life limiting influence on the TBC than accumulated time at 1050 C.

Sol-gel preparation of hydrophobic silica antireflective coatings with low refractive index by base/acid two-step catalysis.

PubMed

Cai, Shuang; Zhang, Yulu; Zhang, Hongli; Yan, Hongwei; Lv, Haibing; Jiang, Bo

2014-07-23

Hydrophobic antireflective coatings with a low refractive index were prepared via a base/acid-catalyzed two-step sol-gel process using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as precursors, respectively. The base-catalyzed hydrolysis of TEOS leads to the formation of a sol with spherical silica particles in the first step. In the second step, the acid-catalyzed MTES hydrolysis and condensation occur at the surface of the initial base-catalyzed spherical silica particles, which enlarge the silica particle size from 12.9 to 35.0 nm. By a dip-coating process, this hybrid sol gives an antireflective coating with a refractive index of about 1.15. Moreover, the water contact angles of the resulted coatings increase from 22.4 to 108.7° with the increases of MTES content, which affords the coatings an excellent hydrophobicity. A "core-shell" particle growth mechanism of the hybrid sol was proposed and the relationship between the microstructure of silica sols and the properties of AR coatings was investigated.

DPAL: Historical Perspective And Summary Of Achievements

DTIC Science & Technology

2013-08-20

of a gas gain medium. The thermal effects existing, for example, in solid state lasers cause aberrations and thermal lensing that degrade the beam...and 500 torr of ethane buffer gas had windows AR coated on both sides (external and internal) and was kept at 98°C. The pump and lasing beams were...back mirror. A 2 cm long cell with antireflection coated windows was filled with metallic cesium and 500 Torr ethane and placed in a heated oven with a

Stable CW Single Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1999-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by tWo methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback'. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback.

Stable CW Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1998-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings (FBG) has been achieved by two methods: (1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element; (2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback.

In Vitro Analysis of Fibronectin-Modified Titanium Surfaces

PubMed Central

Chang, Yu-Chi; Lee, Wei-Fang; Feng, Sheng-Wei; Huang, Haw-Ming; Lin, Che-Tong; Teng, Nai-Chia; Chang, Wei Jen

2016-01-01

Background Glow discharge plasma (GDP) procedure is an effective method for grafting various proteins, including albumin, type I collagen, and fibronectin, onto a titanium surface. However, the behavior and impact of titanium (Ti) surface modification is yet to be unraveled. Purpose The purpose of this study is to evaluate and analyze the biological properties of fibronectin-grafted Ti surfaces treated by GDP. Materials and Methods Grade II Ti discs were initially cleaned and autoclaved to obtain original specimens. Subsequently, the specimens were GDP treated and grafted with fibronectin to form Ar-GDP (Argon GDP treatment only) and GDP-fib (fibronectin coating following GDP treatment) groups. Blood coagulation test and MG-63 cell culture were performed to evaluate the biological effects on the specimen. Results There was no significant difference between Ar-GDP and GDP-fib groups in blood compatibility analysis. While in the MTT test, cellular proliferation was benefited from the presence of fibronectin coating. The numbers of cells on Ar-GDP and GDP-fib specimens were greater than those in the original specimens after 24 h of culturing. Conclusions GDP treatment combined with fibronectin grafting favored MG-63 cell adhesion, migration, and proliferation on titanium surfaces, which could be attributed to the improved surface properties. PMID:26731536

Energy and charge transfer in ionized argon coated water clusters.

PubMed

Kočišek, J; Lengyel, J; Fárník, M; Slavíček, P

2013-12-07

We investigate the electron ionization of clusters generated in mixed Ar-water expansions. The electron energy dependent ion yields reveal the neutral cluster composition and structure: water clusters fully covered with the Ar solvation shell are formed under certain expansion conditions. The argon atoms shield the embedded (H2O)n clusters resulting in the ionization threshold above ≈15 eV for all fragments. The argon atoms also mediate more complex reactions in the clusters: e.g., the charge transfer between Ar(+) and water occurs above the threshold; at higher electron energies above ~28 eV, an excitonic transfer process between Ar(+)* and water opens leading to new products Ar(n)H(+) and (H2O)(n)H(+). On the other hand, the excitonic transfer from the neutral Ar* state at lower energies is not observed although this resonant process was demonstrated previously in a photoionization experiment. Doubly charged fragments (H2O)(n)H2(2+) and (H2O)(n)(2+) ions are observed and Intermolecular Coulomb decay (ICD) processes are invoked to explain their thresholds. The Coulomb explosion of the doubly charged cluster formed within the ICD process is prevented by the stabilization effect of the argon solvent.

Development of electrophoretically deposited hydroxyapatite coatings on anodized nanotubular TiO2 structures: Corrosion and sintering temperature

NASA Astrophysics Data System (ADS)

Goudarzi, Mona; Batmanghelich, Farhad; Afshar, Abdollah; Dolati, Abolghasem; Mortazavi, Golsa

2014-05-01

Hydroxyapatite (HA) coatings in and onto anodized TiO2 nanotube arrays were presented and prepared by electrophoretic deposition technique (EPD). Coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). EPD proved to be an innovative and versatile technique to coat HA on and into nanotubular structures of TiO2 with enhanced adhesion between nanotubes and HA particles provided by mechanical interlocking. After EPD of HA on TiO2 layer, samples were sintered at 400 °C, 600 °C and 800 °C for 2 h in an Ar atmosphere. Effect of EPD processing parameters on thickness of the deposits and rate of deposition was elucidated for HA coatings on the nanotubular TiO2 structures. It was shown that higher applied voltages increase deposition rate and thickness of the coatings. Potentiodynamic polarization measurements proved corrosion protection caused by both HA coating and nanotubular TiO2 structure in simulated body fluid (SBF). Effect of sintering temperature on adhesion strength of HA coatings on TiO2 nanotubes and their composition were also studied.

Influence of Fluoride Ion Concentrations on the Corrosion Behavior of Ta2N Nanocrystalline Coating for Dental Implant Applications

NASA Astrophysics Data System (ADS)

Xu, Jiang; Ma, Jin Jin; Munroe, Paul; Xie, Zong-Han

The development of new corrosion-resistant coatings is often challenging, but strongly driven by the potential benefits such coatings hold. A nanostructured Ta2N coating was deposited on a Ti-6Al-4V substrate in an Ar-N atmosphere using a double cathode glow discharge plasma method with the aim being to improve its corrosion resistance in oral environments. The microstructure of the coating was investigated by a range of methods including XRD, SEM-EDS and TEM. The as-deposited coating exhibited densely packed fibrous structure and the individual fibers were composed of equiaxed grains with an average grain size ˜13nm, arranged along the longitudinal axis of the individual fibers. The electrochemical behavior of the Ta2N nanocrystalline coating was characterized in artificial saliva containing different NaF concentrations by a range of electrochemical techniques, including potentiodynamic measurement, EIS, capacitance and PZFC measurements. It was shown that the coating possessed superior corrosion resistance compared to uncoated Ti-6Al-4V, because its passive film exhibited higher stability against the fluoride ion attack.

Influence of Cu Content on the Microstructure and Mechanical Properties of Cr-Cu-N Coatings

PubMed Central

Ding, Ji Cheng; Zhang, Teng Fei; Wan, Zhi Xin; Mei, Hai Juan; Kang, Myung Chang

2018-01-01

The Cr-Cu-N coatings with various Cu contents (0–25.18 (±0.17) at.%) were deposited on Si wafer and stainless steel (SUS 304) substrates in reactive Ar+N2 gas mixture by a hybrid coating system combining pulsed DC and RF magnetron sputtering techniques. The influence of Cu content on the coating composition, microstructure, and mechanical properties was investigated. The microstructure of the coatings was significantly altered by the introduction of Cu. The deposited coatings exhibit solid solution structure with different compositions in all of the samples. Addition of Cu is intensively favored for preferred orientation growth along (200) direction by restricting in (111) direction. With increasing Cu content, the surface and cross-sectional morphology of coatings were changed from triangle cone-shaped, columnar feature to broccoli-like and compact glassy microstructure, respectively. The mechanical properties including the residual stress, nanohardness, and toughness of the coatings were explored on the basis of Cu content. The highest hardness was obtained at the Cu content of 1.49 (±0.10) at.%. PMID:29552269

Influence of Cu Content on the Microstructure and Mechanical Properties of Cr-Cu-N Coatings.

PubMed

Ding, Ji Cheng; Zhang, Teng Fei; Wan, Zhi Xin; Mei, Hai Juan; Kang, Myung Chang; Wang, Qi Min; Kim, Kwang Ho

2018-01-01

The Cr-Cu-N coatings with various Cu contents (0-25.18 (±0.17) at.%) were deposited on Si wafer and stainless steel (SUS 304) substrates in reactive Ar+N 2 gas mixture by a hybrid coating system combining pulsed DC and RF magnetron sputtering techniques. The influence of Cu content on the coating composition, microstructure, and mechanical properties was investigated. The microstructure of the coatings was significantly altered by the introduction of Cu. The deposited coatings exhibit solid solution structure with different compositions in all of the samples. Addition of Cu is intensively favored for preferred orientation growth along (200) direction by restricting in (111) direction. With increasing Cu content, the surface and cross-sectional morphology of coatings were changed from triangle cone-shaped, columnar feature to broccoli-like and compact glassy microstructure, respectively. The mechanical properties including the residual stress, nanohardness, and toughness of the coatings were explored on the basis of Cu content. The highest hardness was obtained at the Cu content of 1.49 (±0.10) at.%.

Design and fabrication of dichroic mirrors for color separation and recombination of the Kr-Ar laser (white laser)

NASA Astrophysics Data System (ADS)

Park, Jungho; Park, Youngjun; Hwang, Young M.

1997-10-01

Cut-off filters reject all the radiation below and transmit all the above a certain wavelength and vice versa. In this paper, we will study the design and fabrication of a short wave pass or a long wave pass dichroic mirrors for color separation and recombination from the R.G.B. color beam source. In the laser display system, color separation and recombination is very important. We designed the coating layers so that the best performance may be obtained from a 45 degree incident s-polarized light. The following fabrication specification is satisfied in our color separation/recombination of the Kr-Ar laser source. The first dichroic mirror for the blue color separation, maximized on reflectance and transmittance as R > 99% in the blue regions (400 approximately 490 nm) and T > 90% in the green and red region (510 approximately 700 nm). The second dichroic mirror for the color recombination maximized the reflectance and transmittance as R > 99% in the range of 510 approximately 700 nm and T > 90% in the blue color region. In the third dichroic mirror for which it used the color separation and recombination of the green and red simultaneously, maximized the reflectance and transmittance as R > 99% in the green region (510 approximately 560 nm) and T > 90% in the red region. These fabricated mirrors were applied in our laser display projection system. We obtained an excellent result.

Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings

PubMed Central

2014-01-01

Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar+ laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates. PMID:24959110

Naturally inspired SERS substrates fabricated by photocatalytically depositing silver nanoparticles on cicada wings

NASA Astrophysics Data System (ADS)

Tanahashi, Ichiro; Harada, Yoshiyuki

2014-06-01

Densely stacked Ag nanoparticles with an average diameter of 199 nm were effectively deposited on TiO2-coated cicada wings (Ag/TiO2-coated wings) from a water-ethanol solution of AgNO3 using ultraviolet light irradiation at room temperature. It was seen that the surfaces of bare cicada wings contained nanopillar array structures. In the optical absorption spectra of the Ag/TiO2-coated wings, the absorption peak due to the localized surface plasmon resonance (LSPR) of Ag nanoparticles was observed at 440 nm. Strong Surface-enhanced Raman scattering (SERS) signals of Rhodamine 6G adsorbed on the Ag/TiO2-coated wings were clearly observed using the 514.5-nm line of an Ar+ laser. The Ag/TiO2-coated wings can be a promising candidate for naturally inspired SERS substrates.

High-Flux Neutron Generator Facility for Geochronology and Nuclear Physics Research

NASA Astrophysics Data System (ADS)

Waltz, Cory; HFNG Collaboration

2015-04-01

A facility based on a next-generation, high-flux D-D neutron generator (HFNG) is being commissioned at UC Berkeley. The generator is designed to produce monoenergetic 2.45 MeV neutrons at outputs exceeding 1011 n/s. The HFNG is designed around two RF-driven multi-cusp ion sources that straddle a titanium-coated copper target. D + ions, accelerated up to 150 keV from the ion sources, self-load the target and drive neutron generation through the d(d,n)3 He fusion reaction. A well-integrated cooling system is capable of handling beam power reaching 120 kW impinging on the target. The unique design of the HFNG target permits experimental samples to be placed inside the target volume, allowing the samples to receive the highest neutron flux (1011 cm-2 s-1) possible from the generator. In addition, external beams of neutrons will be available simultaneously, ranging from thermal to 2.45 MeV. Achieving the highest neutron yields required carefully designed schemes to mitigate back-streaming of high energy electrons liberated from the cathode target by deuteron bombardment. The proposed science program is focused on pioneering advances in the 40 Ar/39 Ar dating technique for geochronology, new nuclear data measurements, basic nuclear science, and education. An end goal is to become a user facility for researchers. This work is supported by NSF Grant No. EAR-0960138, U.S. DOE LBNL Contract No. DE-AC02-05CH11231, U.S. DOE LLNL Contract No. DE-AC52-07NA27344, and UC Office of the President Award 12-LR-238745.

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

Baker, Kevin L.

The purpose of this LDRD project was to demonstrate high spatial and temporal resolution x-ray imaging using optical detectors, and in particular the VISAR and OHRV diagnostics on the OMEGA laser. The x-ray source being imaged was a backlighter capsule being imploded by 39 beams of the OMEGA laser. In particular this approach utilized a semiconductor with the side facing the backlighter capsule coated with a thin aluminum layer to allow x rays to pass through the metal layer and then get absorbed in the semiconductor. The other side of the semiconductor was AR coated to allow the VISAR ormore » OHRV probe beam to sample the phase change of the semiconductor as the x rays were absorbed in the semiconductor. This technique is capable of acquiring sub-picosecond 2-D or 1-D x-ray images, detector spatial resolution of better than 10 um and the ability to operate in a high neutron flux environment expected on ignition shots with burning plasmas. In addition to demonstrating this technique on the OMEGA laser, several designs were made to improve the phase sensitivity, temporal resolution and number of frames over the existing diagnostics currently implemented on the OMEGA laser. These designs included both 2-d imaging diagnostics as well as improved 1-D imaging diagnostics which were streaked in time.« less

Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings

PubMed Central

Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

2016-01-01

Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings. PMID:26924136

Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings.

PubMed

Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

2016-02-29

Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings.

Co-electrodeposition of hard Ni-W/diamond nanocomposite coatings

NASA Astrophysics Data System (ADS)

Zhang, Xinyu; Qin, Jiaqian; Das, Malay Kumar; Hao, Ruru; Zhong, Hua; Thueploy, Adisak; Limpanart, Sarintorn; Boonyongmaneerat, Yuttanant; Ma, Mingzhen; Liu, Riping

2016-02-01

Electroplated hard chrome coating is widely used as a wear resistant coating to prolong the life of mechanical components. However, the electroplating process generates hexavalent chromium ion which is known carcinogen. Hence, there is a major effort throughout the electroplating industry to replace hard chrome coating. Composite coating has been identified as suitable materials for replacement of hard chrome coating, while deposition coating prepared using traditional co-deposition techniques have relatively low particles content, but the content of particles incorporated into a coating may fundamentally affect its properties. In the present work, Ni-W/diamond composite coatings were prepared by sediment co-electrodeposition from Ni-W plating bath, containing suspended diamond particles. This study indicates that higher diamond contents could be successfully co-deposited and uniformly distributed in the Ni-W alloy matrix. The maximum hardness of Ni-W/diamond composite coatings is found to be 2249 ± 23 Hv due to the highest diamond content of 64 wt.%. The hardness could be further enhanced up to 2647 ± 25 Hv with heat treatment at 873 K for 1 h in Ar gas, which is comparable to hard chrome coatings. Moreover, the addition of diamond particles could significantly enhance the wear resistance of the coatings.

Properties of thin SiC membrane for x-ray mask

NASA Astrophysics Data System (ADS)

Shoki, Tsutomu; Nagasawa, Hiroyuki; Kosuga, Hiroyuki; Yamaguchi, Yoichi; Annaka, Noromichi; Amemiya, Isao; Nagarekawa, Osamu

1993-06-01

We have investigated the effects of film thickness, anti-reflective (AR) coating and surface roughness on the optical transparency of silicon carbide (SiC) membrane. Peak transmittances monotonously increased as the thickness decreased. The transmittance at 633 nm for 1.05 micrometers thick SiC membrane adjusted by reactive ion etching was 70%, and increased up to 80% by an AR coating. SiC membrane with extremely smooth surface of 0.12 nm (Ra) has been obtained by polishing, and had peak transmittances of 69% and 80% at 633 nm for 2.0 micrometers and 1.0 micrometers in thickness, respectively. Poly-crystalline (beta) -SiC membrane in the suitable tensile stress range of 0.3 to 2.0 X 108 Pa and with high Young's modulus of 4.5 X 1011 Pa has been prepared by a hot wall type low pressure chemical vapor deposition, and been found to need to have thickness over 0.7 micrometers to maintain sufficient mechanical strength in processing.

Optimization of imprintable nanostructured a-Si solar cells: FDTD study.

PubMed

Fisker, Christian; Pedersen, Thomas Garm

2013-03-11

We present a finite-difference time-domain (FDTD) study of an amorphous silicon (a-Si) thin film solar cell, with nano scale patterns on the substrate surface. The patterns, based on the geometry of anisotropically etched silicon gratings, are optimized with respect to the period and anti-reflection (AR) coating thickness for maximal absorption in the range of the solar spectrum. The structure is shown to increase the cell efficiency by 10.2% compared to a similar flat solar cell with an optimized AR coating thickness. An increased back reflection can be obtained with a 50 nm zinc oxide layer on the back reflector, which gives an additional efficiency increase, leading to a total of 14.9%. In addition, the patterned cells are shown to be up to 3.8% more efficient than an optimized textured reference cell based on the Asahi U-type glass surface. The effects of variations of the optimized solar cell structure due to the manufacturing process are investigated, and shown to be negligible for variations below ±10%.

Influence of Feedstock Powder Modification by Heat Treatments on the Properties of APS-Sprayed Al2O3-40% TiO2 Coatings

NASA Astrophysics Data System (ADS)

Berger, Lutz-Michael; Sempf, Kerstin; Sohn, Yoo Jung; Vaßen, Robert

2018-04-01

The formation and decomposition of aluminum titanate (Al2TiO5, tialite) in feedstock powders and coatings of the binary Al2O3-TiO2 system are so far poorly understood. A commercial fused and crushed Al2O3-40%TiO2 powder was selected as the feedstock for the experimental series presented in this paper, as the composition is close to that of Al2TiO5. Part of that powder was heat-treated in air at 1150 and 1500 °C in order to modify the phase composition, while not influencing the particle size distribution and processability. The powders were analyzed by thermal analysis, XRD and FESEM including EDS of metallographically prepared cross sections. Only a maximum content of about 45 wt.% Al2TiO5 was possible to obtain with the heat treatment at 1500 °C due to inhomogeneous distribution of Al and Ti in the original powder. Coatings were prepared by plasma spraying using a TriplexPro-210 (Oerlikon Metco) with Ar-H2 and Ar-He plasma gas mixtures at plasma power levels of 41 and 48 kW. Coatings were studied by XRD, SEM including EDS linescans of metallographically prepared cross sections, and microhardness HV1. With the exception of the powder heat-treated at 1500 °C an Al2TiO5-Ti3O5 (tialite-anosovite) solid solution Al2- x Ti1+ x O5 instead of Al2TiO5 existed in the initial powder and the coatings.

Effect of the SiCl₄ Flow Rate on SiBN Deposition Kinetics in SiCl₄-BCl₃-NH₃-H₂-Ar Environment.

PubMed

Li, Jianping; Qin, Hailong; Liu, Yongsheng; Ye, Fang; Li, Zan; Cheng, Laifei; Zhang, Litong

2017-06-07

To improve the thermal and mechanical stability of SiC f /SiC or C/SiC composites with SiBN interphase, SiBN coating was deposited by low pressure chemical vapor deposition (LPCVD) using SiCl₄-BCl₃-NH₃-H₂-Ar gas system. The effect of the SiCl₄ flow rate on deposition kinetics was investigated. Results show that deposition rate increases at first and then decreases with the increase of the SiCl₄ flow rate. The surface of the coating is a uniform cauliflower-like structure at the SiCl₄ flow rate of 10 mL/min and 20 mL/min. The surface is covered with small spherical particles when the flow rate is 30 mL/min. The coatings deposited at various SiCl₄ flow rates are all X-ray amorphous and contain Si, B, N, and O elements. The main bonding states are B-N, Si-N, and N-O. B element and B-N bonding decrease with the increase of SiCl₄ flow rate, while Si element and Si-N bonding increase. The main deposition mechanism refers to two parallel reactions of BCl₃+NH₃ and SiCl₄+NH₃. The deposition process is mainly controlled by the reaction of BCl₃+NH₃.

Lateral mode control in edge-emitting lasers with modified mirrors

NASA Astrophysics Data System (ADS)

Payusov, A.; Serin, A.; Mukhin, I.; Shernyakov, Y.; Zadiranov, Y.; Maximov, M.; Gordeev, N.

2017-11-01

We present a study on lateral mode control in edge-emitting lasers with profiled mirror reflectivity. The object was to eliminate high-order lateral modes in conventional ridge-waveguide InAs/InGaAs QD (quantum dot) lasers with the stripe width of 10 μm. We have used a FIB (focused ion beam) technique to selectively etch windows in the AR (anti-reflection) facet coatings in order to introduce extra mirror losses for the high order modes. This approach allowed us to eliminate the first-order mode lasing without deterioration of the laser parameters. We suppose that further optimisation of the laser heterostructure and window designs may lead to a pure lateral single-mode lasing in the broadened ridge waveguides.

Manufacturing and testing of wavefront filters for DARWIN

NASA Astrophysics Data System (ADS)

Flatscher, R.; Artjushenko, V.; Sakharova, T.; Pereira do Carmo, Joao

2017-11-01

Wavefront filtering is mandatory in the realisation of nulling interferometers with high star light suppression capability required to detect extrasolar planets, such as the one foreseen for the ESA Darwin mission. This paper presents the design, manufacturing, and test results of single mode fibres to be used as wavefront filters in mid-infrared range. Fibres made from chalcogenide glass and silver halide crystals were produced. The first class can serve as wavefront filters up to a wavelength of 11 microns, while silver halide fibres can be used over the full Darwin wavelength range from 6.5 to 18 micron. The chalcogenide glass fibres were drawn by double crucible method whereas polycrystalline fibres from silver halides were fabricated by multiple extrusion from a crystalline preform. Multi-layer AR-coatings for fibre ends were developed and environmentally tested for both types of fibres. Special fibre facet polishing procedures were established, in particular for the soft silver halide fibre ends. Cable design and assembly process were also developed, including termination by SMA-connectors with ceramic ferrules and fibre protection by loose PEEK-tubings to prevent excessive bending and chemical attacks for fibres. The wavefront filtering capability of the fibres was demonstrated on a high quality Mach-Zehnder interferometer. Two different groups of laser sources were used to measure the wavefront filtering of the fibres by using a CO-laser for testing in the lower sub-band and a CO2-laser to check the upper sub-band. Measurements of the fibres far field intensity distribution and transmission were performed for numerous cable samples. Single mode behaviour was observed in more than 25 silver halide fibre cables before AR-coating of their ends, while after that 17 cables were compliant with all technical requirements. Residual cladding modes existing in short single mode fibres were effectively removed by applying of a proper absorbing jacket to the fibre's lateral surface and by adding an oversized output aperture in front of fibre ends. Several fibres were exposed to gamma radiation of total dose of 25, 50, and even 500 krad. No deterioration was found on AR-coated fibre ends and on fibre material. Five fibres were irradiated by proton radiation of 10MeV energy and 1010 p/cm2 equivalent fluence. Several fibres were cooled down to 10 K by plunging them in a dipstick into liquid Helium. Silver halide fibres survived that test when cables were properly assembled. The brittle chalcogenide glass fibres were much more sensitive to thermal gradients and the related cables did not survive the thermal shock. Critical issues have been revealed in multiple drawings of chalcogenide glass fibres where core and cladding composition were not stable at some fabrication stages - resulting in a poor single mode guiding. Much better results have been achieved with polycrystalline fibres from silver halides made with a small core and low NA and enabling single mode guiding in the mid infrared.

Development of technique for air coating and nickel and copper metalization of solar cells

NASA Technical Reports Server (NTRS)

1982-01-01

Solar cells were made with a variety of base metal screen printing inks applied over silicon nitride AR coating and copper electroplated. Fritted and fritless nickel and fritless tin base printing inks were evaluated. Conversion efficiencies as high as 9% were observed with fritted nickel ink contacts, however, curve shapes were generally poor, reflecting high series resistance. Problems encountered in addition to high series reistance included loss of adhesion of the nickel contacts during plating and poor adhesion, oxidation and inferior curve shapes with the tin base contacts.

Demonstration and Validation of Reactive Vitreous Coatings to Prevent Corrosion of Steel Fixtures Attached to Masonry Walls

DTIC Science & Technology

2016-12-01

blend of a hydraulically reactive silicate cement with a glass enameling frit that is fused to steel . Research has shown that when Portland cement is...Silicate Coatings for Protecting and Bonding Reinforcing Steel in Cement -Based Composites,” presented at 26th Army Science Conference, Orlando, FL...Prevent Corrosion of Steel Fixtures Attached to Masonry Walls Final Report on Project F10-AR12 Co ns tr uc tio n En gi ne er in g R es ea rc h La

Modeling Cl2/O2/Ar inductively coupled plasmas used for silicon etching: effects of SiO2 chamber wall coating

NASA Astrophysics Data System (ADS)

Tinck, S.; Boullart, W.; Bogaerts, A.

2011-08-01

In this paper, simulations are performed to gain a better insight into the properties of a Cl2/Ar plasma, with and without O2, during plasma etching of Si. Both plasma and surface properties are calculated in a self-consistent manner. Special attention is paid to the behavior of etch products coming from the wafer or the walls, and how the chamber walls can affect the plasma and the resulting etch process. Two modeling cases are considered. In the first case, the reactor walls are defined as clean (Al2O3), whereas in the second case a SiO2 coating is introduced on the reactor walls before the etching process, so that oxygen will be sputtered from the walls and introduced into the plasma. For this reason, a detailed reaction set is presented for a Cl2/O2/Ar plasma containing etched species, as well as an extensive reaction set for surface processes, including physical and chemical sputtering, chemical etching and deposition processes. Density and flux profiles of various species are presented for a better understanding of the bulk plasma during the etching process. Detailed information is also given on the composition of the surfaces at various locations of the reactor, on the etch products in the plasma and on the surface loss probabilities of the plasma species at the walls, with different compositions. It is found that in the clean chamber, walls are mostly chlorinated (Al2Cl3), with a thin layer of etch products residing on the wall. In the coated chamber, an oxy-chloride layer is grown on the walls for a few nanometers during the etching process. The Cl atom wall loss probability is found to decrease significantly in the coated chamber, hence increasing the etch rate. SiCl2, SiCl4 and SiCl3 are found to be the main etch products in the plasma, with the fraction of SiCl2 being always slightly higher. The simulation results compare well with experimental data available from the literature.

Comparison of Langmuir probe and multipole resonance probe measurements in argon, hydrogen, nitrogen, and oxygen mixtures in a double ICP discharge

NASA Astrophysics Data System (ADS)

Fiebrandt, Marcel; Oberberg, Moritz; Awakowicz, Peter

2017-07-01

The results of a Multipole Resonance Probe (MRP) are compared to a Langmuir probe in measuring the electron density in Ar, H2, N2, and O2 mixtures. The MRP was designed for measurements in industry processes, i.e., coating or etching. To evaluate a possible influence on the MRP measurement due to molecular gases, different plasmas with increasing molecular gas content in a double inductively coupled plasma at 5 Pa and 10 Pa at 500 W are used. The determined electron densities from the MRP and the Langmuir probe slightly differ in H2 and N2 diluted argon plasmas, but diverge significantly with oxygen. In pure molecular gas plasmas, electron densities measured with the MRP are always higher than those measured with the Langmuir Probe, in particular, in oxygen containing mixtures. The differences can be attributed to etching of the tungsten wire in the Ar:O2 mixtures and rf distortion in the pure molecular discharges. The influence of a non-Maxwellian electron energy distribution function, negative ions or secondary electron emission seems to be of no or only minor importance.

Humic acid facilitates the transport of ARS-labeled hydroxyapatite nanoparticles in iron oxyhydroxide-coated sand

USDA-ARS?s Scientific Manuscript database

Hydroxyapatite nanoparticles (nHAP) have been widely used to remediate soil and wastewater contaminated with metals and radionuclides. However, our understanding of nHAP transport and fate is limited in natural environments that exhibit significant variability in solid and solution chemistry. The tr...

Nitrogen-Noble Gas Static Mass Sepectrometry of Genesis Collector Materials

NASA Astrophysics Data System (ADS)

Marty, B.; Burnard, P.; Zimmermann, L.; Robert, P.

2005-03-01

Gases (N, Ne, Ar) are extracted from Au-coated sapphire and diamond-like carbon collectors using an F2 excimer laser, without blank contributions the substrate. N is purified using a low blank CuO/Cu cycle prior to analysis by high resolution multicollector mass spectrometer.

A stretch of 11 amino acids in the betaB-betaC loop of the coat protein of grapevine fanleaf virus is essential for transmission by the nematode Xiphinema index.

PubMed

Schellenberger, Pascale; Andret-Link, Peggy; Schmitt-Keichinger, Corinne; Bergdoll, Marc; Marmonier, Aurélie; Vigne, Emmanuelle; Lemaire, Olivier; Fuchs, Marc; Demangeat, Gérard; Ritzenthaler, Christophe

2010-08-01

Grapevine fanleaf virus (GFLV) and Arabis mosaic virus (ArMV) from the genus Nepovirus, family Secoviridae, cause a severe degeneration of grapevines. GFLV and ArMV have a bipartite RNA genome and are transmitted specifically by the ectoparasitic nematodes Xiphinema index and Xiphinema diversicaudatum, respectively. The transmission specificity of both viruses maps to their respective RNA2-encoded coat protein (CP). To further delineate the GFLV CP determinants of transmission specificity, three-dimensional (3D) homology structure models of virions and CP subunits were constructed based on the crystal structure of Tobacco ringspot virus, the type member of the genus Nepovirus. The 3D models were examined to predict amino acids that are exposed at the external virion surface, highly conserved among GFLV isolates but divergent between GFLV and ArMV. Five short amino acid stretches that matched these topographical and sequence conservation criteria were selected and substituted in single and multiple combinations by their ArMV counterparts in a GFLV RNA2 cDNA clone. Among the 21 chimeric RNA2 molecules engineered, transcripts of only three of them induced systemic plant infection in the presence of GFLV RNA1. Nematode transmission assays of the three viable recombinant viruses showed that swapping a stretch of (i) 11 residues in the betaB-betaC loop near the icosahedral 3-fold axis abolished transmission by X. index but was insufficient to restore transmission by X. diversicaudatum and (ii) 7 residues in the betaE-alphaB loop did not interfere with transmission by the two Xiphinema species. This study provides new insights into GFLV CP determinants of nematode transmission.

A phase one AR/C system design

NASA Technical Reports Server (NTRS)

Kachmar, Peter M.; Polutchko, Robert J.; Matusky, Martin; Chu, William; Jackson, William; Montez, Moises

1991-01-01

The Phase One AR&C System Design integrates an evolutionary design based on the legacy of previous mission successes, flight tested components from manned Rendezvous and Proximity Operations (RPO) space programs, and additional AR&C components validated using proven methods. The Phase One system has a modular, open architecture with the standardized interfaces proposed for Space Station Freedom system architecture.

Fabrication of high quality carbonaceous coating on Cu nanoparticle using poly(vinyl pyrrolidone) and its application for oxidation prevention

NASA Astrophysics Data System (ADS)

Pyo, Youngjun; Choi, Dahyun; Son, Yeon-Ho; Kang, Suhee; Yoon, Eric H.; Jung, Seung-Boo; Kim, Yongil; Sunyong Lee, Caroline

2016-05-01

A novel method of carbonaceous coating on the surface of copper particles was developed through a chemical vapor deposition (CVD) process to prevent the oxidation of copper nanoparticles (CNPs). The types of poly(vinyl pyrrolidone) (PVP) used were K-12 (M W 3,500) and K-30 (M W 45,000). The amounts of PVP used ranged from 10 to 50 wt %. Additionally, processing temperatures of 900 and 875 °C were tested and compared. The optimum CVD process conditions for the carbonaceous coating were as follows: 875 °C processing temperature, 50 wt % K12 PVP solution, and gas conditions of \\text{Ar}:\\text{H}2 = 1:1. The resistivity change in the fabricated copper pattern was confirmed that the initial resistivity value of the ink with a mixing ratio of carbonaceous-coated CNPs to 1-octanethiol-coated CNPs of 4:6 (w/w) maintained its initial resistivity value of 2.93 × 10-7 Ω·m for more than 210 days.

Corrosion studies of DC reactive magnetron sputtered alumina coating on 304 SS

NASA Astrophysics Data System (ADS)

Thangaraj, Baskar; Mahadevan, Krishnan

2017-12-01

Aluminum oxide films on SS 304 deposited by DC reactive magnetron sputtering technique were studied with respect to the composition of the sputter gas (Ar:O2), gas pressure, substrate temperature, current etc. to achieve good insulating films with high corrosion resistance. The films were characterized by XRD and SEM techniques. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements were made under static conditions in order to evaluate the corrosion performance of the alumina-coated SS 304 for various immersion durations in 0.5 M and 1 M NaCl solution. Alumina-coated SS 304 has low corrosion value of 0.4550 and 1.1090MPY for 24 h immersion time in both solutions. The impedance plots for the alumina coated SS 304 in 1 M NaCl solution at different durations are slightly different to when compared to its immersion in 0.5 M NaCl solutions and are composed of two depressed semi circles. For the alumina coated film, the impedance spectrum decreased, when immersion time increased.

Characterization of micron-sized, optical coating defects by photothermal deflection microscopy

NASA Astrophysics Data System (ADS)

Abate, J. A.; Schmid, A. W.; Guardalben, M. G.; Smith, D. J.; Jacobs, S. D.

1984-04-01

Information about the localized absorbing defects in optical thin films is required for a better understanding of laser induced damage. Photothermal deflection microscopy offers a nondestructive optical diagnostic which yields spatially resolved absorption data on simple and multiple layer AR and HR dielectric coatings. The computer controlled apparatus used to generate absorption maps of dielectric thin films and an experiment in which a partial correlation between localized absorption sites and damage caused by nanosecond laser irradiation at 351 nm is established are described. An absolute calibration of absorption for our measurement technique is presented here. Micron sized absorbtive defects of Cu were introduced into our coatings to provide a means of calibration. Also presented here are some preliminary data on the modification of the absorption signatures measured by photothermal deflection as a function of the location of the defect within the coating layers.

Self-organization of SiO{sub 2} nanodots deposited by chemical vapor deposition using an atmospheric pressure remote microplasma

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

Arnoult, G.; Belmonte, T.; Henrion, G.

Self-organization of SiO{sub 2} nanodots is obtained by chemical vapor deposition out of hexamethyldisiloxane (HMDSO) and atmospheric pressure remote Ar-O{sub 2} plasma operating at high temperature (1200-1600 K). The dewetting of the film being deposited when it is still thin enough (<500 nm) is found to be partly responsible for this self-organization. When the coating becomes thicker (approx1 mum), and for relatively high contents in HMDSO, SiO{sub 2} walls forming hexagonal cells are obtained on a SiO{sub 2} sublayer. For thicker coatings (>1 mum), droplet-shaped coatings with a Gaussian distribution in thickness over their width are deposited. The coatings aremore » submitted to high compressive stress. When it is relaxed, 'nestlike structures' made of nanoribbons are synthesized.« less

Modification of the structure and composition of Ca10(PO4)6(OH)2 ceramic coatings by changing the deposition conditions in O2 and Ar

NASA Astrophysics Data System (ADS)

Donkov, N.; Zykova, A.; Safonov, V.; Kolesnikov, D.; Goncharov, I.; Yakovin, S.; Georgieva, V.

2014-05-01

Hydroxyapatite Ca10(PO4)6(OH)2 (HAp) is a material considered to be used to form structural matrices in the mineral phase of bone, dentin and enamel. HAp ceramic materials and coatings are widely applied in medicine and dentistry because of their ability to increase the tissue response to the implant surface and promote bone ingrowth and osseoconduction processes. The deposition conditions affect considerably the structure and bio-functionality of the HAp coatings. We focused our research on developing deposition methods allowing a precise control of the structure and stoichiometric composition of HAp thin films. We found that the use of O2 as a reactive gas improves the quality of the sputtered hydroxyapatite coatings by resulting in the formation of films of better stoichiometry with a fine crystalline structure.

Reactive ion-beam-sputtering of fluoride coatings for the UV/VUV range

NASA Astrophysics Data System (ADS)

Schink, Harald; Kolbe, Jurgen; Zimmermann, F.; Ristau, Detlev; Welling, Herbert

1991-06-01

Fluoride coatings produced by thermal evaporation suffer from high scatter losses ageing and cracking due to high tensile stress. These problems impose severe limitations to the production of low loss multilayer coatings for the VUV range. A key position for improved performance is the microstructure of the layers. The aim of our investigations is to improve the microstructure of A1F3- and LaF3-'' films by ionbeamsputtering. Scatter measurements of single layers revealed lower values for lBS than for boat evaporation. Unfortunately sputtered fluoride films nave high absorption losses caused by decomposition of the coating material. By sputtering in reactive atmospheres and annealing we were able to reduce the absorption losses significantly. Antireflective as well as high reflective coatings were produced. Reflection and transmission values were obtained with a VUV-spectrophotometer. Damage tests at the 193 mu ArF laser wavelength were performed at the Laser-Laboratorium Gttingen. Key words: ion-beamsputtering fluoride films UVcoatings VUV-coatings color-center laser damage A]. F3 MgF2 LaF3. 1.

Resistant Bacterial Spore Coats and Their Breakdown During Germination

DTIC Science & Technology

2010-01-01

proteins are released into the outer layers of the spore (SspA, B) or released into the supernatant ( SspE ). 4. Two major proteases of broad...40 30 20 15 10 3.5 N o ve x Sh ar p cw lD ge rm in at io n e xu d at e N o ve x Sh ar p cw lD ge rm in at io n e xu d at e CotA CotQ SodA SspE ...Finally, and unexpectedly, SspE , the major gamma-type SASP (small acid soluble protein) present in the inner cellular compartment of dormant spores, and

Large area space qualified thermoelectrically (TE) cooled HgCdTe MW photovoltaic detectors for the Halogen Occultation Experiment (HALOE)

NASA Technical Reports Server (NTRS)

Norton, P. W.; Zimmermann, P. H.; Briggs, R. J.; Hartle, N. M.

1986-01-01

Large-area, HgCdTe MW photovoltaic detectors have been developed for the NASA-HALOE instrument scheduled for operation on the Upper Atmospheric Research Satellite. The photodiodes will be TE-cooled and were designed to operate in the 5.1-5.4 micron band at 185 K to measure nitric oxide concentrations in the atmosphere. The active area required 15 micron thick devices and a full backside common contact. Reflections from the backside contact doubled the effective thickness of the detectors. Optical interference from reflections was eliminated with a dual layer front surface A/R coating. Bakeout reliability was optimized by having Au metallization for both n and p interconnects. Detailed performance data and a model for the optical stack are presented.

ASRM test report: Autoclave cure process development

NASA Technical Reports Server (NTRS)

Nachbar, D. L.; Mitchell, Suzanne

1992-01-01

ASRM insulated segments will be autoclave cured following insulation pre-form installation and strip wind operations. Following competitive bidding, Aerojet ASRM Division (AAD) Purchase Order 100142 was awarded to American Fuel Cell and Coated Fabrics Company, Inc. (Amfuel), Magnolia, AR, for subcontracted insulation autoclave cure process development. Autoclave cure process development test requirements were included in Task 3 of TM05514, Manufacturing Process Development Specification for Integrated Insulation Characterization and Stripwind Process Development. The test objective was to establish autoclave cure process parameters for ASRM insulated segments. Six tasks were completed to: (1) evaluate cure parameters that control acceptable vulcanization of ASRM Kevlar-filled EPDM insulation material; (2) identify first and second order impact parameters on the autoclave cure process; and (3) evaluate insulation material flow-out characteristics to support pre-form configuration design.

Effect of the SiCl4 Flow Rate on SiBN Deposition Kinetics in SiCl4-BCl3-NH3-H2-Ar Environment

PubMed Central

Li, Jianping; Qin, Hailong; Liu, Yongsheng; Ye, Fang; Li, Zan; Cheng, Laifei; Zhang, Litong

2017-01-01

To improve the thermal and mechanical stability of SiCf/SiC or C/SiC composites with SiBN interphase, SiBN coating was deposited by low pressure chemical vapor deposition (LPCVD) using SiCl4-BCl3-NH3-H2-Ar gas system. The effect of the SiCl4 flow rate on deposition kinetics was investigated. Results show that deposition rate increases at first and then decreases with the increase of the SiCl4 flow rate. The surface of the coating is a uniform cauliflower-like structure at the SiCl4 flow rate of 10 mL/min and 20 mL/min. The surface is covered with small spherical particles when the flow rate is 30 mL/min. The coatings deposited at various SiCl4 flow rates are all X-ray amorphous and contain Si, B, N, and O elements. The main bonding states are B-N, Si-N, and N-O. B element and B-N bonding decrease with the increase of SiCl4 flow rate, while Si element and Si-N bonding increase. The main deposition mechanism refers to two parallel reactions of BCl3+NH3 and SiCl4+NH3. The deposition process is mainly controlled by the reaction of BCl3+NH3. PMID:28772986

Sol-gel preparation of self-cleaning SiO2-TiO2/SiO2-TiO2 double-layer antireflective coating for solar glass

NASA Astrophysics Data System (ADS)

Lin, Wensheng; Zheng, Jiaxian; Yan, Lianghong; Zhang, Xinxiang

2018-03-01

Self-cleaning SiO2-TiO2/SiO2-TiO2 double-layer antireflective (AR) coating is prepared by sol-gel process. SiO2 sol is prepared by using tetraethyl orthosilicate (TEOS) as precursor and ammonia as catalyst, while TiO2 sol was prepared by using tetrabutyl orthotitanate (TBOT) as precursor and hydrochloric acid as catalyst. The effect of TiO2 content on refractive index, abrasion-resistance and photo-catalytic activity of SiO2-TiO2 hybrid thin films or powders is systematically investigated. It is found that the refractive index of SiO2-TiO2 hybrid thin films increases gradually from 1.18 to 1.53 as the weight ratio of TiO2 to SiO2 increased from 0 to 1.0. The SiO2-TiO2 hybrid thin film and powder possesses good abrasion-resistance and photo-catalytic activity, respectively, as the weight ratio of TiO2 to SiO2 is 0.4. The degradation degree of Rhodamine B by SiO2-TiO2 hybrid powder is 88.3%. Finally, SiO2-TiO2/SiO2-TiO2 double-layer AR coating with high transmittance, abrasion-resistance and self-cleaning property is realized.

High-performance visible/UV CCD focal plane technology for spacebased applications

NASA Technical Reports Server (NTRS)

Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

1993-01-01

We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

Effect of Charging Electron Exposure on 1064nm Transmission Through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics

NASA Technical Reports Server (NTRS)

Ottens, Brian P.; Connelly, Joseph; Brown, Stephen; Roeder, James; Kauder, Lonny; Cavanaugh, John

2010-01-01

Experiments measuring the effect of electron exposure on 1064nm transmission for optical sapphire were conducted. Detailed before and after inspections did not identify any resulting Litchenburg patterns. Pre- and post-exposure 1064nm transmission measurements are compared.

Effect of Charging Electron Exposure on 1064nm Transmission through Bare Sapphire Optics and SiO2 over HfO2 AR-coated Sapphire Optics

NASA Technical Reports Server (NTRS)

Ottens, Brian P.; Connelly, Joseph; Brown, Stephen; Roeder, james; Kauder, Lonny; Cavanaugh, John

2008-01-01

Experiments measuring the effect of electron exposure on 1064nm transmission for optical sapphire were conducted. Detailed before and after inspections did not identify any resulting Litchenburg patterns. Pre- and post-exposure 1064nm transmission measurements are compared.

Efficient 2(nd) and 4(th) harmonic generation of a single-frequency, continuous-wave fiber amplifier.

PubMed

Sudmeyer, Thomas; Imai, Yutaka; Masuda, Hisashi; Eguchi, Naoya; Saito, Masaki; Kubota, Shigeo

2008-02-04

We demonstrate efficient cavity-enhanced second and fourth harmonic generation of an air-cooled, continuous-wave (cw), single-frequency 1064 nm fiber-amplifier system. The second harmonic generator achieves up to 88% total external conversion efficiency, generating more than 20-W power at 532 nm wavelength in a diffraction-limited beam (M(2) < 1.05). The nonlinear medium is a critically phase-matched, 20-mm long, anti-reflection (AR) coated LBO crystal operated at 25 degrees C. The fourth harmonic generator is based on an AR-coated, Czochralski-grown beta-BaB(2)O(4) (BBO) crystal optimized for low loss and high damage threshold. Up to 12.2 W of 266-nm deep-UV (DUV) output is obtained using a 6-mm long critically phase-matched BBO operated at 40 degrees C. This power level is more than two times higher than previously reported for cw 266-nm generation. The total external conversion efficiency from the fundamental at 1064 nm to the fourth harmonic at 266 nm is >50%.

Evaluation of Encapsulant Adhesion to Surface Metallization of Photovoltaic Cells: Preprint

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

Tracy, Jared; Dauskardt, Reinhold; Bosco, Nick

Delamination of encapsulant materials from PV cell surfaces often appears to originate at regions with metallization. Using a fracture mechanics based metrology, the adhesion of EVA encapsulant to screen printed silver metallization was evaluated. At room temperature, the fracture energy, Gc [J/m2], of the EVA/silver interface (952 J/m2) was ~70% lower than that of the EVA/AR coating (>2900 J/m2) and ~60% lower than that of the EVA to the surface of cell (2265 J/m2). After only 300 hours of damp heat aging, the adhesion energy of the silver interface dropped to and plateaued at ~50-60 J/m2, while that of themore » EVA/AR coating and EVA/cell remained mostly unchanged. Elemental surface analysis showed that the EVA separates from the silver in a purely adhesive manner, indicating that bonds at the interface were likely displaced in the presence of humidity and elevated temperature, and may explain the propensity for delamination to occur at metallized surfaces in the field.« less

Encapsulant Adhesion to Surface Metallization on Photovoltaic Cells

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

Tracy, Jared; Bosco, Nick; Dauskardt, Reinhold

Delamination of encapsulant materials from PV cell surfaces often appears to originate at regions with metallization. Using a fracture mechanics based metrology, the adhesion of ethylene vinyl acetate (EVA) encapsulant to screen-printed silver metallization was evaluated. At room temperature, the fracture energy Gc [J/m2] of the EVA/silver interface (952 J/m2) was ~70% lower than that of the EVA/antireflective (AR) coating (>2900 J/m2) and ~60% lower than that of the EVA to the surface of cell (2265 J/m2). After only 300 h of damp heat aging, the adhesion energy of the silver interface dropped to and plateaued at ~50-60 J/m2 whilemore » that of the EVA/AR coating and EVA/cell remained mostly unchanged. Elemental surface analysis showed that the EVA separates from the silver in a purely adhesive manner, indicating that bonds at the interface were likely displaced in the presence of humidity and chemical byproducts at elevated temperature, which in part accounts for the propensity of metalized surfaces to delaminate in the field.« less

Rain Erosion Resistant AR Coating for ZnS Windows

DTIC Science & Technology

1980-05-10

number) FLUR Windows, Rain Erosion Coatings; High Performance Aircrait in’- Coa t f ng De 1)os I t L on Tv c I n I (Iu es ; Me t ro Io gy ; TLest, i11g...developed for jinaging el"(rtrlo opt ical sensor systems intended for use on high performance a irer; Ia It s, ’ as F-4, F-15, F-16, A-10 J-18 and F-ill...for Forward Looking Infrared (FLIk) thermal imaging sensors such as those in- corporated in the PAVE TACK pod and the IR Maverick Missile. ’This

A simple method for the preparation of activated carbon fibers coated with graphite nanofibers.

PubMed

Kim, Byung-Joo; Park, Soo-Jin

2007-11-15

A simple method is described for the preparation of activated carbon fibers (ACFs) coated with graphite nanofibers (GNFs). Low-pressure-plasma mixed-gas (Ar/O2) treatment of the ACFs led to the growth of GNFs on their surface. The growth was greater at higher power inputs, and from TEM observations the GNFs were seen to be of herringbone type. It was found that the N2 adsorption capacity of the ACFs did not sharply decrease, and that volume resistivity of the ACFs enhanced as a result of this treatment.

Diffusion-Driven Charge Transport in Light Emitting Devices

PubMed Central

Oksanen, Jani; Suihkonen, Sami

2017-01-01

Almost all modern inorganic light-emitting diode (LED) designs are based on double heterojunctions (DHJs) whose structure and current injection principle have remained essentially unchanged for decades. Although highly efficient devices based on the DHJ design have been developed and commercialized for energy-efficient general lighting, the conventional DHJ design requires burying the active region (AR) inside a pn-junction. This has hindered the development of emitters utilizing nanostructured ARs located close to device surfaces such as nanowires or surface quantum wells. Modern DHJ III-N LEDs also exhibit resistive losses that arise from the DHJ device geometry. The recently introduced diffusion-driven charge transport (DDCT) emitter design offers a novel way to transport charge carriers to unconventionally placed ARs. In a DDCT device, the AR is located apart from the pn-junction and the charge carriers are injected into the AR by bipolar diffusion. This device design allows the integration of surface ARs to semiconductor LEDs and offers a promising method to reduce resistive losses in high power devices. In this work, we present a review of the recent progress in gallium nitride (GaN) based DDCT devices, and an outlook of potential DDCT has for opto- and microelectronics. PMID:29231900

Development of nanostructured PVD coatings for total knee replacement joints using HIPIMS

NASA Astrophysics Data System (ADS)

Sugumaran, Arunprabhu A.

The aim of this study was to develop thin film coatings for total knee replacement joints using high power impulse magnetron sputtering (HIPIMS). An industrial size four cathode magnetron sputtering system equipped with direct current (DC) and HIPIMS power supplies was used for this purpose. Initially, Plasma diagnostics were carried out using optical emission spectroscopy (OES) while sputtering Ti target in Ar + N2 atmosphere by utilizing various HIP IMS/conventional DCMS (henceforth UBM) source combinations by varying the process parameters such as coil current and N2 flow. Then, single layer titanium nitride (TiN) coating was deposited by varying the degree of HIPIMS utilisation and the process parameters such as bias voltage and coil current to thoroughly understand the effect of degree of HIPIMS utilisation on the microstructure, residual stress, texture, mechanical, tribological and corrosion properties of such coatings. The degree of HIPIMS utilisation was altered by increasing the number of HIPIMS targets used for the deposition. Four different source combinations were used for this purpose, as follows: 4 cathodes in conventional DCMS mode to deposit pure UBM coating, 1 HIPIMS + 3UBM and 2HIPIMS + 2UBM cathodes to deposit combined HIPIMS/UBM coatings and 2HIPIMS cathodes to deposit pure HIPIMS coatings. TiN/NbN, TiCN/NbCN and CrN/NbN multilayer coatings were deposited on CoCr alloy test buttons along with other (HSS, SS and Si) substrates since our intended application is on total knee replacement joints made of CoCr alloy. The knowledge gained by investigating the TiN (Ar + N[2]) plasma and the properties of TiN was used to determine the process parameters for depositing the multilayer coatings. X- ray diffraction (XRD) technique was used for calculating the texture, residual stress and bilayer thickness of the coatings. Nanoindentation method was used to determine the nano hardness of the coatings. The adhesion strength of the coatings was estimated by scratch and Rockwell indentation tests. Pin on disc method was used for the tribological studies such as coefficient of friction and coefficient of wear. Surface roughness measurements were carried out using a surface profiler. Microstructural characterisation of the coatings was carried out using scanning electron microscope (SEM) and transmission electron microscope (TEM). Potentiodynamic polarisation method was utilised to study the corrosion performance of the coatings. Raman spectroscopy was used to study the constituents of the corrosion products and evaluate the corrosion damage. OES measurements revealed that the degree of metal ions (Ti[1+]) increased with increasing degree of HIPIMS utilisation. The hardness, tribological and corrosion properties of TiN coatings improved with increasing degree of HIPIMS utilisation. TiN and multilayer coatings deposited by HIPIMS exhibited a smooth columnar microstructure without any voided region along the column boundaries. TiN/NbN, TiCN/NbCN and CrN/NbN multilayer coatings deposited on CoCr alloy, HSS and SS test buttons exhibited superior mechanical, tribological and corrosion properties as compared to the underlying substrate.

The MaNGA integral field unit fiber feed system for the Sloan 2.5 m telescope

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

Drory, N.; MacDonald, N.; Byler, N.

2015-02-01

We describe the design, manufacture, and performance of bare-fiber integral field units (IFUs) for the SDSS-IV survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) on the the Sloan 2.5 m telescope at Apache Point Observatory. MaNGA is a luminosity-selected integral-field spectroscopic survey of 10{sup 4} local galaxies covering 360–1030 nm at R∼2200. The IFUs have hexagonal dense packing of fibers with packing regularity of 3 μm (rms), and throughput of 96 ± 0.5% from 350 nm to 1 μm in the lab. Their sizes range from 19 to 127 fibers (3–7 hexagonal layers) using Polymicro FBP 120:132:150 μm core:clad:buffermore » fibers to reach a fill fraction of 56%. High throughput (and low focal-ratio degradation (FRD)) is achieved by maintaining the fiber cladding and buffer intact, ensuring excellent surface polish, and applying a multi-layer anti-reflection (AR) coating of the input and output surfaces. In operations on-sky, the IFUs show only an additional 2.3% FRD-related variability in throughput despite repeated mechanical stressing during plate plugging (however other losses are present). The IFUs achieve on-sky throughput 5% above the single-fiber feeds used in SDSS-III/BOSS, attributable to equivalent performance compared to single fibers and additional gains from the AR coating. The manufacturing process is geared toward mass-production of high-multiplex systems. The low-stress process involves a precision ferrule with a hexagonal inner shape designed to lead inserted fibers to settle in a dense hexagonal pattern. The ferrule ID is tapered at progressively shallower angles toward its tip and the final 2 mm are straight and only a few microns larger than necessary to hold the desired number of fibers. Our IFU manufacturing process scales easily to accommodate other fiber sizes and can produce IFUs with substantially larger fiber counts. To assure quality, automated testing in a simple and inexpensive system enables complete characterization of throughput and fiber metrology. Future applications include larger IFUs, higher fill factors with stripped buffer, de-cladding, and lenslet coupling.« less

The MaNGA Integral Field Unit Fiber Feed System for the Sloan 2.5 m Telescope

NASA Astrophysics Data System (ADS)

Drory, N.; MacDonald, N.; Bershady, M. A.; Bundy, K.; Gunn, J.; Law, D. R.; Smith, M.; Stoll, R.; Tremonti, C. A.; Wake, D. A.; Yan, R.; Weijmans, A. M.; Byler, N.; Cherinka, B.; Cope, F.; Eigenbrot, A.; Harding, P.; Holder, D.; Huehnerhoff, J.; Jaehnig, K.; Jansen, T. C.; Klaene, M.; Paat, A. M.; Percival, J.; Sayres, C.

2015-02-01

We describe the design, manufacture, and performance of bare-fiber integral field units (IFUs) for the SDSS-IV survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) on the the Sloan 2.5 m telescope at Apache Point Observatory. MaNGA is a luminosity-selected integral-field spectroscopic survey of 104 local galaxies covering 360-1030 nm at R˜ 2200. The IFUs have hexagonal dense packing of fibers with packing regularity of 3 μm (rms), and throughput of 96 ± 0.5% from 350 nm to 1 μm in the lab. Their sizes range from 19 to 127 fibers (3-7 hexagonal layers) using Polymicro FBP 120:132:150 μm core:clad:buffer fibers to reach a fill fraction of 56%. High throughput (and low focal-ratio degradation (FRD)) is achieved by maintaining the fiber cladding and buffer intact, ensuring excellent surface polish, and applying a multi-layer anti-reflection (AR) coating of the input and output surfaces. In operations on-sky, the IFUs show only an additional 2.3% FRD-related variability in throughput despite repeated mechanical stressing during plate plugging (however other losses are present). The IFUs achieve on-sky throughput 5% above the single-fiber feeds used in SDSS-III/BOSS, attributable to equivalent performance compared to single fibers and additional gains from the AR coating. The manufacturing process is geared toward mass-production of high-multiplex systems. The low-stress process involves a precision ferrule with a hexagonal inner shape designed to lead inserted fibers to settle in a dense hexagonal pattern. The ferrule ID is tapered at progressively shallower angles toward its tip and the final 2 mm are straight and only a few microns larger than necessary to hold the desired number of fibers. Our IFU manufacturing process scales easily to accommodate other fiber sizes and can produce IFUs with substantially larger fiber counts. To assure quality, automated testing in a simple and inexpensive system enables complete characterization of throughput and fiber metrology. Future applications include larger IFUs, higher fill factors with stripped buffer, de-cladding, and lenslet coupling.

Reducing detrimental electrostatic effects in Casimir-force measurements and Casimir-force-based microdevices

NASA Astrophysics Data System (ADS)

Xu, Jun; Klimchitskaya, G. L.; Mostepanenko, V. M.; Mohideen, U.

2018-03-01

It is well known that residual electrostatic forces create significant difficulties in precise measurements of the Casimir force and the wide use of Casimir-operated microdevices. We experimentally demonstrate that, with the help of Ar-ion cleaning of the surfaces, it is possible to make electrostatic effects negligibly small compared to the Casimir interaction. Our experimental setup consists of a dynamic atomic force microscope supplemented with an Ar-ion gun and argon reservoir. The residual potential difference between the Au-coated surfaces of a sphere and those of a plate was measured both before and after in situ Ar-ion cleaning. It is shown that this cleaning decreases the magnitude of the residual potential by up to an order of magnitude and makes it almost independent of the separation. The gradient of the Casimir force was measured using ordinary samples subjected to Ar-ion cleaning. The obtained results are shown to be in good agreement both with previous precision measurements using specially selected samples and with theoretical predictions of the Lifshitz theory. The conclusion is made that the suggested method of in situ Ar-ion cleaning is effective in reducing the electrostatic effects and therefore is a great resource for experiments on measuring the Casimir interaction and for Casimir-operated microdevices.

The Space Station air revitalization subsystem design concept

NASA Technical Reports Server (NTRS)

Ray, C. D.; Ogle, K. Y.; Tipps, R. W.; Carrasquillo, R. L.; Wieland, P.

1987-01-01

The current status of the Space Station (SS) Environmental Control and Life Support System (ECLSS) Air Revitalization Subsystem (ARS) design is outlined. ARS performance requirements are provided, along with subsystem options for each ARS function and selected evaluations of the relative merits of each subsystem. Detailed computer models that have been developed to analyze individual subsystem performance capabilities are also discussed. A summary of ARS subsystem level testing planned and completed by NASA Marshall Space Flight Center (MSFC) is given.

In-Situ Subsurface Coating of Corroded Steel Sheet Pile Structures: Final Report on Project F08-AR06

DTIC Science & Technology

2017-09-01

scraped the sheet pile wall with an excavator. After scraping the out-pans with a flat edge bucket, the contractor welded a blade on the bucket...unusual striations were parallel grooves running at 30 – 45 degrees from the vertical. Some patterns cross each other symmetrically. The stria- tions

Control and enhancement of the oxygen storage capacity of ceria films by variation of the deposition gas atmosphere during pulsed DC magnetron sputtering

NASA Astrophysics Data System (ADS)

Eltayeb, Asmaa; Vijayaraghavan, Rajani K.; McCoy, Anthony; Venkatanarayanan, Anita; Yaremchenko, Aleksey A.; Surendran, Rajesh; McGlynn, Enda; Daniels, Stephen

2015-04-01

In this study, nanostructured ceria (CeO2) films are deposited on Si(100) and ITO coated glass substrates by pulsed DC magnetron sputtering using a CeO2 target. The influence on the films of using various gas ambients, such as a high purity Ar and a gas mixture of high purity Ar and O2, in the sputtering chamber during deposition are studied. The film compositions are studied using XPS and SIMS. These spectra show a phase transition from cubic CeO2 to hexagonal Ce2O3 due to the sputtering process. This is related to the transformation of Ce4+ to Ce3+ and indicates a chemically reduced state of CeO2 due to the formation of oxygen vacancies. TGA and electrochemical cyclic voltammetry (CV) studies show that films deposited in an Ar atmosphere have a higher oxygen storage capacity (OSC) compared to films deposited in the presence of O2. CV results specifically show a linear variation with scan rate of the anodic peak currents for both films and the double layer capacitance values for films deposited in Ar/O2 mixed and Ar atmosphere are (1.6 ± 0.2) × 10-4 F and (4.3 ± 0.5) × 10-4 F, respectively. Also, TGA data shows that Ar sputtered samples have a tendency to greater oxygen losses upon reduction compared to the films sputtered in an Ar/O2 mixed atmosphere.

Preparation and Evaluation of Ribonuclease-Resistant Viral HIV RNA Standards Based on Armored RNA Technology

PubMed

Gholami, Mohammad; Ravanshad, Mehrdad; Baesi, Kazem; Samiee, Siamak M.; Hosseini Rozbahani, Negin; Mohraz, Minoo

2018-05-19

The human immunodeficiency virus type 1 (HIV-1) is an infectious viral agent that gradually extinguishes the immune system, resulting in acquired immune deficiency syndrome (AIDS). The aim of this study was to construct an RNA-positive control based on armored (AR) RNA technology, using HIV-1 RNA as a model. The MS2 maturase, a coat protein gene (at positions 1765 to 1787) and HIV-1 pol gene were cloned into pET-32a plasmid. The prepared plasmid was transformed into Escherichia coli strain BL2 (DE3), and the expression of the construct was induced by 1 mM of isopropyl-L-thio-D-galactopyranoside (IPTG) at 37 °C for 16 h to obtain the fabricated AR RNA. The AR RNA was precipitated and purified using polyethylene glycol and Sephacryl S-200 chromatography. The stability of AR RNA was evaluated by treatment with DNase I and RNase A and confirmed by transmission electron microscopy and gel agarose electrophoresis. Tenfold serial dilution of AR RNA from 101 to 105 was prepared; real-time PCR assays had a range of detection between 101 and 105, R2 value was 0.998, and the slope of the standard curve was -3.33. Prepared AR RNA, as a positive control, could be used as a basis for launching an in-house HIV-1 virus assay and other infectious agents. It can be readily available to laboratories and HIV research centers. The AR RNA is non-infectious and highly resistant to ribonuclease enzyme and can reduce the risk of infection in the clinical laboratory.

Design and Development of a Quantitative TaqMan Real-Time PCR Assay for Evaluation of HIV-1 (group M) Viral Load in Plasma Using Armored RNA Standard.

PubMed

Gholami, Mohammad; Baesi, Kazem; Rouzbahani, Negin H; Mohraz, Minoo

2018-06-01

Human immunodeficiency virus-1 (HIV-1) is a viral infectious agent that gradually extinguishes the immune system, resulting in the acquired immune deficiency syndrome (AIDS). The aim of this study was to develop a TaqMan based detection assay to evaluate HIV-1 plasma viral load and to construct a stable internal positive control (IPC) and external positive control (EPC) RNA based on Armored RNA (AR) technology. The MS2 maturase, coat protein gene and HIV-1 pol gene were cloned in pET-32a plasmid. The recently fabricated recombinant plasmid was transformed into Escherichia coli strain BL2 (DE3) and protein expression and Armored RNA was fabricated in presence of isopropyl-L-thio-D-galactopyranoside (IPTG). The Armored RNA was precipitated and purified by polyethylene glycol (PEG) and sephacryl S-200 chromatography. The stability of Armored RNA was evaluated by treatment with DNase I and RNase A and confirmed by transmission electron microscopy (TEM) and gel agarose electrophoresis. The specificity, sensitivity, inter- and intra-day precision, and the dynamic range of the assay were experimentally determined. The AR was stable in presence of ribonuclease, and the assay had a dynamic detection range from 101 to 105 copies of AR. The coefficient of variation (CV) was 4.8% for intra-assay and 5.8% for inter-assay precision. Clinical specificity and sensitivity of the assay were assessed at 100% and 96.66%, respectively. The linear regression analysis confirmed a high correlation between the in-house and the commercial assay, Real Star HIV-1-qRTPCR, respectively (R2 = 0.888). The AR standard is non-infectious and highly resistant in the presence of ribonuclease. The TaqMan assay developed is able to quantify HIV viral load based on a novel conserved region of HIV-1 pol gene which has minimal sequence inconsistency.

Titanium dioxide antireflection coating for silicon solar cells by spray deposition

NASA Technical Reports Server (NTRS)

Kern, W.; Tracy, E.

1980-01-01

A high-speed production process is described for depositing a single-layer, quarter-wavelength thick antireflection coating of titanium dioxide on metal-patterned single-crystal silicon solar cells for terrestrial applications. Controlled atomization spraying of an organotitanium solution was selected as the most cost-effective method of film deposition using commercial automated equipment. The optimal composition consists of titanium isopropoxide as the titanium source, n-butyl acetate as the diluent solvent, sec-butanol as the leveling agent, and 2-ethyl-1-hexanol to render the material uniformly depositable. Application of the process to the coating of circular, large-diameter solar cells with either screen-printed silver metallization or with vacuum-evaporated Ti/Pd/Ag metallization showed increases of over 40% in the electrical conversion efficiency. Optical characteristics, corrosion resistance, and several other important properties of the spray-deposited film are reported. Experimental evidence indicates a wide tolerance in the coating thickness upon the overall efficiency of the cell. Considerations pertaining to the optimization of AR coatings in general are discussed, and a comprehensive critical survey of the literature is presented.

Low-pressure RF remote plasma cleaning of carbon-contaminated B4C-coated optics

NASA Astrophysics Data System (ADS)

Moreno Fernández, H.; Thomasset, M.; Sauthier, G.; Rogler, D.; Dietsch, R.; Barrett, R.; Carlino, V.; Pellegrin, E.

2017-05-01

Boron carbide (B4C) - due to its exceptional mechanical properties - is one of the few existing materials that can withstand the extremely high brilliance of the photon beam from free electron lasers (FELs) and is thus of considerable interest for optical applications in this field. However, as in the case of many other optics operated at modern accelerator-, plasma-, or laser-based light source facilities, B4C-coated optics are subject to ubiquitous carbon contaminations. These contaminations - that are presumably produced via cracking of CHx and CO2 molecules by photoelectrons emitted from the optical components - represent a serious issue for the operation of the pertinent high performance beamlines due to a severe reduction of photon flux and beam coherence, not necessarily restricted to the photon energy range of the carbon K-edge. Thus, a variety of B4C cleaning technologies have been developed at different laboratories with varying success [1]. Here, we present a study regarding the low-pressure RF plasma cleaning of a series of carbon-contaminated B4C test samples via an inductively coupled O2/Ar and Ar/H2 remote RF plasma produced using the IBSS GV10x plasma source following previous studies using the same RF plasma source [2, 3]. Results regarding the chemistry, morphology as well as other aspects of the B4C optical coatings and surfaces before and after the plasma cleaning process are reported.

In Vitro Biocompatibility of Si Alloyed Multi-Principal Element Carbide Coatings

PubMed Central

Vladescu, Alina; Titorencu, Irina; Dekhtyar, Yuri; Jinga, Victor; Pruna, Vasile; Balaceanu, Mihai; Dinu, Mihaela; Pana, Iulian; Vendina, Viktorija

2016-01-01

In the current study, we have examined the possibility to improve the biocompatibility of the (TiZrNbTaHf)C through replacement of either Ti or Ta by Si. The coatings were deposited on Si and 316L stainless steel substrates by magnetron sputtering in an Ar+CH4 mixed atmosphere and were examined for elemental composition, chemical bonds, surface topography, surface electrical charge and biocompatible characteristics. The net surface charge was evaluated at nano and macroscopic scale by measuring the electrical potential and work function, respectively. The biocompatible tests comprised determination of cell viability and cell attachment to the coated surface. The deposited coatings had C/(metal+Si) ratios close to unity, while a mixture of metallic carbide, free-carbon and oxidized species formed on the film surface. The coatings’ surfaces were smooth and no influence of surface roughness on electrical charge or biocompatibility was found. The biocompatible characteristics correlated well with the electrical potential/work function, suggesting a significant role of surface charge in improving biocompatibility, particularly cell attachment to coating's surface. Replacement of either Ti or Ta by Si in the (TiZrNbTaHf)C coating led to an enhanced surface electrical charge, as well as to superior biocompatible properties, with best results for the (TiZrNbSiHf)C coating. PMID:27571361

Structural and tribological properties of CrTiAlN coatings on Mg alloy by closed-field unbalanced magnetron sputtering ion plating

NASA Astrophysics Data System (ADS)

Shi, Yongjing; Long, Siyuan; Yang, Shicai; Pan, Fusheng

2008-09-01

In this paper, a series of multi-layer hard coating system of CrTiAlN has been prepared by closed-field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique in a gas mixture of Ar + N 2. The coatings were deposited onto AZ31 Mg alloy substrates. During deposition step, technological temperature and metallic atom concentration of coatings were controlled by adjusting the currents of different metal magnetron targets. The nitrogen level was varied by using the feedback control of plasma optical emission monitor (OEM). The structural, mechanical and tribological properties of coatings were characterized by means of X-ray photoelectron spectrometry, high-resolution transmission electron microscope, field emission scanning electron microscope (FESEM), micro-hardness tester, and scratch and ball-on-disc tester. The experimental results show that the N atomic concentration increases and the oxide on the top of coatings decreases; furthermore the modulation period and the friction coefficient decrease with the N 2 level increasing. The outstanding mechanical property can be acquired at medium N 2 level, and the CrTiAlN coatings on AZ31 Mg alloy substrates outperform the uncoated M42 high speed steel (HSS) and the uncoated 316 stainless steel (SS).

Laser formation of titanium nitride films as a result of Ti coating modification in a nitrogen atmosphere

NASA Astrophysics Data System (ADS)

Eskin, Sergei

1998-12-01

Laser treatment of the 303 and 416 stainless steels with Ti precoating was studied. CW CO2 and UV ArF excimer lasers were used. The TiN films were formed at a treatment velocity of 0.5 to 3 - 5 cm/sec and a power density of CO2 laser at (3 - 5) 104 W/cm2. X-ray diffractometry, x-ray mapping and Auger electron spectroscopy techniques indicated a TiN phase on the surface with oxygen content 12 - 25 at%. The thickness of the TiN film was 0.3 - 0.4 micrometers after treatment of the 5 micrometers Ti coating and about 900 angstroms for the 0.3 micrometers coating. Some characteristics of TiN films were examined and features of the nitriding process are discussed.

An abrasion-resistant and broadband antireflective silica coating by block copolymer assisted sol-gel method.

PubMed

Zou, Liping; Li, Xiaoguang; Zhang, Qinghua; Shen, Jun

2014-09-02

A double-layer broadband antireflective (AR) coating was prepared on glass substrate via sol-gel process using two kinds of acid-catalyzed TEOS-derived silica sols. The relative dense layer with a porosity of ∼10% was obtained from an as-prepared sol, while the porous layer with a porosity of ∼55% was from a modified one with block copolymer (BCP) Pluronic F127 as template which results in abundant ordered mesopores. The two layers give rise to a reasonable refractive index gradient from air to the substrate and thus high transmittance in a wide wavelength range, and both of them have the same tough skeleton despite different porosity, for which each single-layer and the double-layer coatings all behaved well in the mechanical property tests. The high transmittance and the strong ability of resisting abrasion make this coating promising for applications in some harsh conditions. In addition, the preparation is simple, low-cost, time-saving, and flexible for realizing the optical property.

Characterization of PEG-Like Macromolecular Coatings on Plasma Modified NiTi Alloy

NASA Astrophysics Data System (ADS)

Yang, Jun; Gao, Jiacheng; Chang, Peng; Wang, Jianhua

2008-04-01

A poly (ethylene glycol) (PEG-like) coating was developed to improve the biocompatibility of Nickel-Titanium (NiTi) alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a room temperature of 298 K through a ECR (electron-cyclotron resonance) cold-plasma enhanced chemical vapor deposition method using tetraglyme (CH3-O-(CH2-CH2-O)4-CH3) as a precursor. A power supply with a frequency of 2.45 GHz was applied to ignite the plasma with Ar(argon) used as the carrier gas. Based on the atomic force microscopy (AFM) studies, a thin smooth coating on NiTi substrates with highly amorphous functional groups on the modified NiTi surfaces were mainly the same accumulated stoichiometric ratio of C and O with PEG. The vitro studies showed that platelet-rich plasma (PRP) adsorption on the modified NiTi alloy surface was significantly reduced. This study indicated that plasma surface modification changes the surface components of NiTi alloy and subsequently improves its biocompatibility.

Inhibition of aldose reductase from cataracted eye lenses by finger millet (Eleusine coracana) polyphenols.

PubMed

Chethan, S; Dharmesh, Shylaja M; Malleshi, Nagappa G

2008-12-01

Retinopathy is a major cause of blindness in the Western world, while cataract is one of the three major causes of blindness worldwide. Diabetes is one of the major risk factor in retinopathy and cataract. The prevalence of blindness in India is 15 per 1000 while cataract alone accounts for 80% of this blindness. Diabetes induced cataract is characterized by an accumulation of sorbitol which is mediated by the action of a key enzyme aldose reductase (AR). Non-enzymatic glycation (binding of glucose to protein molecule) induced during diabetes appear to be the key factor for AR mediated sugar-induced cataract. Finger millet polyphenols (FMP) being a major anti-diabetic and antioxidant component, we have evaluated them for AR inhibiting activity. Phenolic constituents in FMP such as gallic, protocatechuic, p-hydroxy benzoic, p-coumaric, vanillic, syringic, ferulic, trans-cinnamic acids and the quercetin inhibited cataract eye lens effectively, the latter was more potent with an IC(50) of 14.8nM. Structure function analysis revealed that phenolics with OH group at 4th position was important for aldose reductase inhibitory property. Also the presence of neighboring O-methyl group in phenolics denatured the AR activity. Finger millet seed coat polyphenols (SCP) has been found to inhibit AR reversibly by non-competitive inhibition. Results thus, provide a stronger evidence for the potentials of FMP in inhibiting cataractogenesis in humans.

48 CFR 1942.202-70 - Authorized Representative of the Contracting Officer (AR/CO).

Code of Federal Regulations, 2010 CFR

2010-10-01

... of the Contracting Officer (AR/CO). 1942.202-70 Section 1942.202-70 Federal Acquisition Regulations... Administration 1942.202-70 Authorized Representative of the Contracting Officer (AR/CO). The Contracting Officer... of the Contracting Officer (AR/CO). Such designation shall apply to a single contract, must be in...

Design, synthesis, and biological characterization of metabolically stable selective androgen receptor modulators.

PubMed

Marhefka, Craig A; Gao, Wenqing; Chung, Kiwon; Kim, Juhyun; He, Yali; Yin, Donghua; Bohl, Casey; Dalton, James T; Miller, Duane D

2004-02-12

A series of nonsteroidal ligands were synthesized as second-generation agonists for the androgen receptor (AR). These ligands were designed to eliminate metabolic sites identified in one of our first-generation AR agonists, which was inactive in vivo due to its rapid metabolism to inactive constituents. The binding affinity of these compounds was evaluated using AR isolated from rat ventral prostate. These second-generation compounds bound the AR in a high affinity and stereoselective manner, with K(i) values ranging from about 4 to 130 nM. The ability of these ligands to stimulate AR-mediated transcriptional activation was examined in cells transfected with the human AR and a hormone-dependent luciferase reporter gene. Although some compounds were unable to stimulate AR-mediated transcription, several demonstrated activity similar to that of dihydrotestosterone (DHT, an endogenous steroidal ligand for the AR). We also evaluated the in vivo pharmacologic activity of selected compounds in castrated male rats. Three compounds were identified as selective androgen receptor modulators (SARMs), exhibiting significant anabolic activity while having only moderate to minimal androgenic activity in vivo.

Design, Synthesis, and Biological Characterization of Metabolically Stable Selective Androgen Receptor Modulators

PubMed Central

Marhefka, Craig A.; Gao, Wenqing; Chung, Kiwon; Kim, Juhyun; He, Yali; Yin, Donghua; Bohl, Casey; Dalton, James T.; Miller, Duane D.

2007-01-01

A series of nonsteroidal ligands were synthesized as second-generation agonists for the androgen receptor (AR). These ligands were designed to eliminate metabolic sites identified in one of our first-generation AR agonists, which was inactive in vivo due to its rapid metabolism to inactive constituents. The binding affinity of these compounds was evaluated using AR isolated from rat ventral prostate. These second-generation compounds bound the AR in a high affinity and stereoselective manner, with Ki values ranging from about 4 to 130 nM. The ability of these ligands to stimulate AR-mediated transcriptional activation was examined in cells transfected with the human AR and a hormone-dependent luciferase reporter gene. Although some compounds were unable to stimulate AR-mediated transcription, several demonstrated activity similar to that of dihydrotestosterone (DHT, an endogenous steroidal ligand for the AR). We also evaluated the in vivo pharmacologic activity of selected compounds in castrated male rats. Three compounds were identified as selective androgen receptor modulators (SARMs), exhibiting significant anabolic activity while having only moderate to minimal androgenic activity in vivo. PMID:14761201

An ergonomics action research demonstration: integrating human factors into assembly design processes.

PubMed

Village, J; Greig, M; Salustri, F; Zolfaghari, S; Neumann, W P

2014-01-01

In action research (AR), the researcher participates 'in' the actions in an organisation, while simultaneously reflecting 'on' the actions to promote learning for both the organisation and the researchers. This paper demonstrates a longitudinal AR collaboration with an electronics manufacturing firm where the goal was to improve the organisation's ability to integrate human factors (HF) proactively into their design processes. During the three-year collaboration, all meetings, workshops, interviews and reflections were digitally recorded and qualitatively analysed to inform new 'actions'. By the end of the collaboration, HF tools with targets and sign-off by the HF specialist were integrated into several stages of the design process, and engineers were held accountable for meeting the HF targets. We conclude that the AR approach combined with targeting multiple initiatives at different stages of the design process helped the organisation find ways to integrate HF into their processes in a sustainable way. Researchers acted as a catalyst to help integrate HF into the engineering design process in a sustainable way. This paper demonstrates how an AR approach can help achieve HF integration, the benefits of using a reflective stance and one method for reporting an AR study.

An ion source for radiofrequency-pulsed glow discharge time-of-flight mass spectrometry

NASA Astrophysics Data System (ADS)

González Gago, C.; Lobo, L.; Pisonero, J.; Bordel, N.; Pereiro, R.; Sanz-Medel, A.

2012-10-01

A Grimm-type glow discharge (GD) has been designed and constructed as an ion source for pulsed radiofrequency GD spectrometry when coupled to an orthogonal time of flight mass spectrometer. Pulse shapes of argon species and analytes were studied as a function of the discharge conditions using a new in-house ion source (UNIOVI GD) and results have been compared with a previous design (PROTOTYPE GD). Different behavior and shapes of the pulse profiles have been observed for the two sources evaluated, particularly for the plasma gas ionic species detected. In the more analytically relevant region (afterglow), signals for 40Ar+ with this new design were negligible, while maximum intensity was reached earlier in time for 41(ArH)+ than when using the PROTOTYPE GD. Moreover, while maximum 40Ar+ signals measured along the pulse period were similar in both sources, 41(ArH)+ and 80(Ar2)+ signals tend to be noticeable higher using the PROTOTYPE chamber. The UNIOVI GD design was shown to be adequate for sensitive direct analysis of solid samples, offering linear calibration graphs and good crater shapes. Limits of detection (LODs) are in the same order of magnitude for both sources, although the UNIOVI source provides slightly better LODs for those analytes with masses slightly higher than 41(ArH)+.

Critical Issues in Research Design in Action Research in an SME Development Context

ERIC Educational Resources Information Center

McGrath, Helen; O'Toole, Thomas

2012-01-01

Purpose: The main aim of this paper is to develop guidelines on the critical issues to consider in research design in an action research (AR) environment for SME network capability development. Design/methodology/approach: The issues in research design for AR studies are developed from the authors' experience in running learning sets but, in…

Directional Atherectomy Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis and Maintain Vessel Patency: Twelve-Month Results of the DEFINITIVE AR Study.

PubMed

Zeller, Thomas; Langhoff, Ralf; Rocha-Singh, Krishna J; Jaff, Michael R; Blessing, Erwin; Amann-Vesti, Beatrice; Krzanowski, Marek; Peeters, Patrick; Scheinert, Dierk; Torsello, Giovanni; Sixt, Sebastian; Tepe, Gunnar

2017-09-01

Studies assessing drug-coated balloons (DCB) for the treatment of femoropopliteal artery disease are encouraging. However, challenging lesions, such as severely calcified, remain difficult to treat with DCB alone. Vessel preparation with directional atherectomy (DA) potentially improves outcomes of DCB. DEFINITIVE AR study (Directional Atherectomy Followed by a Paclitaxel-Coated Balloon to Inhibit Restenosis and Maintain Vessel Patency-A Pilot Study of Anti-Restenosis Treatment) was a multicenter randomized trial designed to estimate the effect of DA before DCB to facilitate the development of future end point-driven randomized studies. One hundred two patients with claudication or rest pain were randomly assigned 1:1 to DA+DCB (n=48) or DCB alone (n=54), and 19 additional patients with severely calcified lesions were treated with DA+DCB. Mean lesion length was 11.2±4.0 cm for DA+DCB and 9.7±4.1 cm for DCB ( P =0.05). Predilation rate was 16.7% for DA+DCB versus 74.1% for DCB; postdilation rate was 6.3% for DA+DCB versus 33.3% for DCB. Technical success was superior for DA+DCB (89.6% versus 64.2%; P =0.004). Overall bail-out stenting rate was 3.7%, and rate of flow-limiting dissections was 19% for DCB and 2% for DA+DCB ( P =0.01). One-year primary outcome of angiographic percent diameter stenosis was 33.6±17.7% for DA+DCB versus 36.4±17.6% for DCB ( P =0.48), and clinically driven target lesion revascularization was 7.3% for DA+DCB and 8.0% for DCB ( P =0.90). Duplex ultrasound patency was 84.6% for DA+DCB, 81.3% for DCB ( P =0.78), and 68.8% for calcified lesions. Freedom from major adverse events at 1 year was 89.3% for DA+DCB and 90.0% for DCB ( P =0.86). DA+DCB treatment was effective and safe, but the study was not powered to show significant differences between the 2 methods of revascularization in 1-year follow-up. An adequately powered randomized trial is warranted. http://www.clinicaltrials.gov. Unique Identifier: NCT01366482. Copyright © 2017 The Author(s).

Dip-coating of nano-sized CeO2 on SiC membrane and its effect on thermal diffusivity.

PubMed

Park, Jihye; Jung, Miewon

2014-05-01

CeO2-SiC mixed composite membrane was fabricated with porous SiC ceramic and cerium oxide powder synthesized by sol-gel process. This CeO2-SiC membrane and SiC membrane which is made by the purified SiC ceramic were pressed and sintered in Ar atmosphere. And then, the SiC membrane was dip-coated by cerium oxide precursor sol solution and heat-treated in air. The surface morphology, particle size, porosity and structure analysis of the mixing and dip-coating SiC membrane were monitored by FE-SEM and X-ray diffraction analysis. Surface area, pore volume and pore diameter were determined by BET instrument. Thermal diffusivity was measured by laser flash method with increasing temperature. The relation between porosity and thermal diffusivity from different preparation process has been discussed on this study.

Effects of chloride additives on the mechanical stability and environmental durability of porous MgF2 thin films

NASA Astrophysics Data System (ADS)

Schütz, F.; Scheurell, K.; Scholz, G.; Kemnitz, E.

2016-09-01

Porous antireflective thin films, prepared of nanoscopic MgF2 sols, exhibit a low refraction index and are useful for various optical applications. Due to their porosity, film stability and durability suffer from mechanical abrasion and water solubility, respectively. Hence, we present approaches of improved mechanical stability of MgF2 layers induced by chloride addition. Antireflective (AR) films were produced by dip-coating followed by thermal treatment. Afterwards, film stability and environmental durability was strained by crockmeter and water stability tests, respectively. In comparison to films prepared from chloride-free MgF2 sols, chloride mingled sols form coatings with increased mechanical stability and a lower solubility.

Effects of Augmented Reality on Student Achievement and Self-Efficacy in Vocational Education and Training

ERIC Educational Resources Information Center

Sirakaya, Mustafa; Cakmak, Ebru Kilic

2018-01-01

This study aimed to test the impact of augmented reality (AR) use on student achievement and self-efficacy in vocational education and training. For this purpose, a marker-based AR application, called HardwareAR, was developed. HardwareAR provides information about characteristics of hardware components, ports and assembly. The research design was…

Design of Mobile Augmented Reality in Health Care Education: A Theory-Driven Framework.

PubMed

Zhu, Egui; Lilienthal, Anneliese; Shluzas, Lauren Aquino; Masiello, Italo; Zary, Nabil

2015-09-18

Augmented reality (AR) is increasingly used across a range of subject areas in health care education as health care settings partner to bridge the gap between knowledge and practice. As the first contact with patients, general practitioners (GPs) are important in the battle against a global health threat, the spread of antibiotic resistance. AR has potential as a practical tool for GPs to combine learning and practice in the rational use of antibiotics. This paper was driven by learning theory to develop a mobile augmented reality education (MARE) design framework. The primary goal of the framework is to guide the development of AR educational apps. This study focuses on (1) identifying suitable learning theories for guiding the design of AR education apps, (2) integrating learning outcomes and learning theories to support health care education through AR, and (3) applying the design framework in the context of improving GPs' rational use of antibiotics. The design framework was first constructed with the conceptual framework analysis method. Data were collected from multidisciplinary publications and reference materials and were analyzed with directed content analysis to identify key concepts and their relationships. Then the design framework was applied to a health care educational challenge. The proposed MARE framework consists of three hierarchical layers: the foundation, function, and outcome layers. Three learning theories-situated, experiential, and transformative learning-provide foundational support based on differing views of the relationships among learning, practice, and the environment. The function layer depends upon the learners' personal paradigms and indicates how health care learning could be achieved with MARE. The outcome layer analyzes different learning abilities, from knowledge to the practice level, to clarify learning objectives and expectations and to avoid teaching pitched at the wrong level. Suggestions for learning activities and the requirements of the learning environment form the foundation for AR to fill the gap between learning outcomes and medical learners' personal paradigms. With the design framework, the expected rational use of antibiotics by GPs is described and is easy to execute and evaluate. The comparison of specific expected abilities with the GP personal paradigm helps solidify the GP practical learning objectives and helps design the learning environment and activities. The learning environment and activities were supported by learning theories. This paper describes a framework for guiding the design, development, and application of mobile AR for medical education in the health care setting. The framework is theory driven with an understanding of the characteristics of AR and specific medical disciplines toward helping medical education improve professional development from knowledge to practice. Future research will use the framework as a guide for developing AR apps in practice to validate and improve the design framework.

Design of Mobile Augmented Reality in Health Care Education: A Theory-Driven Framework

PubMed Central

Lilienthal, Anneliese; Shluzas, Lauren Aquino; Masiello, Italo; Zary, Nabil

2015-01-01

Background Augmented reality (AR) is increasingly used across a range of subject areas in health care education as health care settings partner to bridge the gap between knowledge and practice. As the first contact with patients, general practitioners (GPs) are important in the battle against a global health threat, the spread of antibiotic resistance. AR has potential as a practical tool for GPs to combine learning and practice in the rational use of antibiotics. Objective This paper was driven by learning theory to develop a mobile augmented reality education (MARE) design framework. The primary goal of the framework is to guide the development of AR educational apps. This study focuses on (1) identifying suitable learning theories for guiding the design of AR education apps, (2) integrating learning outcomes and learning theories to support health care education through AR, and (3) applying the design framework in the context of improving GPs’ rational use of antibiotics. Methods The design framework was first constructed with the conceptual framework analysis method. Data were collected from multidisciplinary publications and reference materials and were analyzed with directed content analysis to identify key concepts and their relationships. Then the design framework was applied to a health care educational challenge. Results The proposed MARE framework consists of three hierarchical layers: the foundation, function, and outcome layers. Three learning theories—situated, experiential, and transformative learning—provide foundational support based on differing views of the relationships among learning, practice, and the environment. The function layer depends upon the learners’ personal paradigms and indicates how health care learning could be achieved with MARE. The outcome layer analyzes different learning abilities, from knowledge to the practice level, to clarify learning objectives and expectations and to avoid teaching pitched at the wrong level. Suggestions for learning activities and the requirements of the learning environment form the foundation for AR to fill the gap between learning outcomes and medical learners’ personal paradigms. With the design framework, the expected rational use of antibiotics by GPs is described and is easy to execute and evaluate. The comparison of specific expected abilities with the GP personal paradigm helps solidify the GP practical learning objectives and helps design the learning environment and activities. The learning environment and activities were supported by learning theories. Conclusions This paper describes a framework for guiding the design, development, and application of mobile AR for medical education in the health care setting. The framework is theory driven with an understanding of the characteristics of AR and specific medical disciplines toward helping medical education improve professional development from knowledge to practice. Future research will use the framework as a guide for developing AR apps in practice to validate and improve the design framework. PMID:27731839

Electrochemical properties of Sn-based nanopowders synthesized by a pulsed wire evaporation method and effect of binder coating

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

Ha, Jong-Keun; Song, Ju-Seok; Cho, Gyu-Bong

Highlights: • Sn-based nanoparticles are fabricated by using the pulsed wire evaporation method. • The electrodes are prepared by mixing the graphene and coating the surface. • Coating the surface of electrode is used with brushing of simple and facile method. • The electrochemical measurements are performed with galvanostatic experiments. • The coating electrode maintains capacity nearly of 501 mAh g{sup −1} up to 100 cycles. - Abstract: Sn-based nanoparticles are prepared with the O{sub 2} concentrations in chamber of Ar atmosphere (by v/v) by using the pulsed wire evaporation (PWE) method. The prepared electrodes are only Sn-based powder electrode,more » its binder coating electrode and Sn-based powder/graphene nanocomposite electrode. Morphology and structure of the synthesized powders and electrodes are investigated with a field emission scanning electron microscope (FE-SEM) and an X-ray diffraction (XRD) analysis. The electrochemical measurements were performed with galvanostatic cycling experiments using a coin type cell of CR2032 (Ø20, T3.2 mm). The binder coating electrode is superior to others and maintains delithiation capacity nearly of 501 mAh g{sup −1} as 58.3% of first delithiation capacity at 0.2 C-rate up to 100 cycles.« less

Tailored synthesis of TiC/a-C nanocomposite tribological coatings

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

Martinez-Martinez, D.; Lopez-Cartes, C.; Justo, A.

2005-11-15

Composite coatings made of nanocrystalline TiC (nc-TiC) particles and amorphous carbon (a-C) have been prepared in a double magnetron sputtering system using graphite and titanium targets under Ar bombardment. Chemical composition and microstructure of coatings were studied by transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), and x-ray diffraction (XRD) for a set of samples prepared varying the ratio and intensity of power applied to each magnetron. Changes in coatings microstructure, from a quasipolycrystalline TiC to a nanocomposite formed by nanocrystals of TiC embedded in an amorphous matrix of carbon (nc-TiC/a-C), are observed depending on the synthesis conditions. Tribologicalmore » and mechanical properties of coatings were tested using a pin-on-disk tribometer and an ultramicrohardness indenter, respectively. Coatings with moderate hardness (7-27 GPa), low friction (0.1-0.2), and low wear rates (k{approx}10{sup -7} mm{sup 3}/N m) were obtained. A percentage between 15% and 30% of TiC is found as an optimum value to get a good compromise between good mechanical and tribological properties. Finally, a mapping of the mechanical and tribological properties of the nc-TiC/a-C system is presented for the synthesis conditions employed.« less

Tailoring nanocrystalline diamond coated on titanium for osteoblast adhesion.

PubMed

Pareta, Rajesh; Yang, Lei; Kothari, Abhishek; Sirinrath, Sirivisoot; Xiao, Xingcheng; Sheldon, Brian W; Webster, Thomas J

2010-10-01

Diamond coatings with superior chemical stability, antiwear, and cytocompatibility properties have been considered for lengthening the lifetime of metallic orthopedic implants for over a decade. In this study, an attempt to tailor the surface properties of diamond films on titanium to promote osteoblast (bone forming cell) adhesion was reported. The surface properties investigated here included the size of diamond surface features, topography, wettability, and surface chemistry, all of which were controlled during microwave plasma enhanced chemical-vapor-deposition (MPCVD) processes using CH4-Ar-H2 gas mixtures. The hardness and elastic modulus of the diamond films were also determined. H2 concentration in the plasma was altered to control the crystallinity, grain size, and topography of the diamond coatings, and specific plasma gases (O2 and NH3) were introduced to change the surface chemistry of the diamond coatings. To understand the impact of the altered surface properties on osteoblast responses, cell adhesion tests were performed on the various diamond-coated titanium. The results revealed that nanocrystalline diamond (grain sizes <100 nm) coated titanium dramatically increased surface hardness, and the introduction of O2 and NH3 during the MPCVD process promoted osteoblast adhesion on diamond and, thus, should be further studied for improving orthopedic applications. Copyright 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

Interface microstructure engineering by high power impulse magnetron sputtering for the enhancement of adhesion

NASA Astrophysics Data System (ADS)

Ehiasarian, A. P.; Wen, J. G.; Petrov, I.

2007-03-01

An excellent adhesion of hard coatings to steel substrates is paramount in practically all application areas. Conventional methods utilize Ar glow etching or cathodic arc discharge pretreatments that have the disadvantage of producing weak interfaces or adding droplets, respectively. One tool for interface engineering is high power impulse magnetron sputtering (HIPIMS). HIPIMS is based on conventional sputtering with extremely high peak power densities reaching 3kWcm-2 at current densities of >2Acm-2. HIPIMS of Cr and Nb was used to prepare interfaces on 304 stainless steel and M2 high speed steel (HSS). During the pretreatment, the substrates were biased to Ubias=-600V and Ubias=-1000V in the environment of a HIPIMS of Cr and Nb plasma. The bombarding flux density reached peak values of 300mAcm-2 and consisted of highly ionized metal plasma containing a high proportion of Cr1+ and Nb1+. Pretreatments were also carried out with Ar glow discharge and filtered cathodic arc as comparison. The adhesion was evaluated for coatings consisting of a 0.3μm thick CrN base layer and a 4μm thick nanolayer stack of CrN /NbN with a period of 3.4nm, hardness of HK0.025=3100, and residual stress of -1.8GPa. For HIPIMS of Cr pretreatment, the adhesion values on M2 HSS reached scratch test critical load values of LC=70N, thus comparing well to LC=51N for interfaces pretreated by arc discharge plasmas and to LC=25N for Ar etching. Cross sectional transmission electron microscopy studies revealed a clean interface and large areas of epitaxial growth in the case of HIPIMS pretreatment. The HIPIMS pretreatment promoted strong registry between the orientation of the coating and polycrystalline substrate grains due to the incorporation of metal ions and the preservation of crystallinity of the substrate. Evidence and conditions for the formation of cube-on-cube epitaxy and axiotaxy on steel and γ-TiAl substrates are presented.

Integrated Projectile Systems Synthesis Model (IPSSM)

DTIC Science & Technology

1976-08-01

Lethal area effectiveness Batch mode I terior ballistics Trajectory calculations Weapon system modeling ""TRACT (Cenetsmae an revers elds It ecesuy and...Ballistics (AR) 29 E. Terminal Effectiveness Calculations (LA) 31 F. 6-D Trajectory (TR) 32 G. Recoil Mechanism Design (RM) 33 H. Sabot Design (SD) 33 I...Exterior Ballistics Program (AR) 79 Key Variable Input D2 Exterior Ballistics Program (AR) 89 List of Tables E Terminal Effectiveness Program (LA) 93

Manufacturing of composite titanium-titanium nitride coatings by reactive very low pressure plasma spraying (R-VLPPS)

NASA Astrophysics Data System (ADS)

Vautherin, B.; Planche, M.-P.; Quet, A.; Bianchi, L.; Montavon, G.

2014-11-01

Very Low Pressure Plasma Spraying (VLPPS) is an emerging spray process nowadays intensively studied by many research centers in the World. To date, studies are mostly focused on the manufacturing of ceramic or metallic coatings. None refers to composite coatings manufacturing by reactive plasma spraying under very low pressure (i.e., ~150 Pa). This paper aims at presenting the carried-out developments and some results concerning the manufacturing of composite coatings by reactive spraying. Titanium was selected as metallic material in order to deposit titanium-nitride titanium coatings (Ti-TiN). Nitrogen was used as plasma gas and was injected along an Ar-H2-N2 plasma jet via a secondary injector in order to reach the nitrogen content on the substrate surface. Thus, different kind of reactive mechanisms were highlighted. Resulting coatings were characterized by Scanning Electron Microscopy (SEM) observations. Porous microstructures are clearly identified and the deposits exhibit condensed vapours and molten particles. Glow Discharge Optical Emission Spectroscopy (GDOES) analysis evidenced nitrogen inside the deposits and X-Ray Diffraction (XRD) analysis confirmed the formation of titanium nitride phases, such as TiN and Ti2N, depending upon the location of the nitrogen injection. Microhardness values as high as 800 VHN were measured on manufactured samples (to be compared to 220 VHN for pure titanium VLPPS-manufactured coatings).

Sintering and Creep Behavior of Plasma-Sprayed Zirconia and Hafnia Based Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

1998-01-01

The sintering and creep of plasma-sprayed ceramic thermal barrier coatings under high temperature conditions are complex phenomena. Changes in thermomechanical and thermophysical properties and in the stress response of these coating systems as a result of the sintering and creep processes are detrimental to coating thermal fatigue resistance and performance. In this paper, the sintering characteristics of ZrO2-8wt%y2O3, ZrO2-25wt%CeO2-2.5wt%Y2O3, ZrO2-6w%NiO- 9wt%Y2O3, ZrO2-6wt%Sc2O3-2wt%y2O3 and HfO2-27wt%y2O3 coating materials were investigated using dilatometry. It was found that the HfO2-Y2O3 and baseline ZrO2-Y2O3 exhibited the best sintering resistance, while the NiO-doped ZrO2-Y2O3 showed the highest shrinkage strain rates during the tests. Higher shrinkage strain rates of the coating materials were also observed when the specimens were tested in Ar+5%H2 as compared to in air. This phenomenon was attributed to an enhanced metal cation interstitial diffusion mechanism under the reducing conditions. It is proposed that increased chemical stability of coating materials will improve the material sintering resistance.

Synthesis and characterization of carbon-coated cobalt ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Bakhshi, Hamed; Shokuhfar, Ali; Vahdati, Nima

2016-09-01

Cobalt ferrite nanoparticles (CFNPs) were prepared via a reverse micelle method. The CFNPs were subsequently coated with carbon shells by means of thermal chemical vapor deposition (TCVD). In this process, acetylene gas (C2H2) was used as a carbon source and the coating was carried out for 1, 2, or 3 h at 750°C. The Ar/C2H2 ratio was 10:1. Heating during the TCVD process resulted in a NP core size that approached 30 nm; the thickness of the shell was less than 10 nm. The composition, structure, and morphology of the fabricated composites were characterized using X-ray diffraction, simultaneous thermal analysis, transmission electron microscopy, high-resolution transmission electron microscopy, and selected-area diffraction. A vibrating sample magnetometer was used to survey the samples' magnetic properties. The deposited carbon shell substantially affected the growth and magnetic properties of the CFNPs. Micro-Raman spectroscopy was used to study the carbon coating and revealed that the deposited carbon comprised graphite, multiwalled carbon nanotubes, and diamond- like carbon. With an increase in coating time, the intensity ratio between the amorphous and ordered peaks in the Raman spectra decreased, which indicated an increase in crystallite size.

Noninvasive Detection of AR-FL/AR V7 as a Predictive Biomarker for Therapeutic Resistance in Men with Metastatic Castration-Resistant Prostate Cancer

DTIC Science & Technology

2016-10-01

AWARD NUMBER: W81XWH-15-2-0050 TITLE: Noninvasive Detection of AR -FL/ AR -V7 as a Predictive Biomarker for Therapeutic Resistance in Men with...report are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision unless so designated...Detection of AR -FL/ AR -V7 as a Predictive Biomarker for Therapeutic Resistance in Men with Metastatic Castration-Resistant Prostate Cancer 5c. PROGRAM

Noninvasive Detection of AR-FL/AR-V7 as a Predictive Biomarker for Therapeutic Resistance in Men with Metastatic Castration-Resistant Prostate Cancer

DTIC Science & Technology

2017-10-01

AWARD NUMBER: W81XWH-15-2-0050 TITLE: Noninvasive Detection of AR -FL/ AR -V7 as a Predictive Biomarker for Therapeutic Resistance in Men with...report are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision unless so designated by...Detection of AR -FL/ AR -V7 as a Predictive Biomarker for Therapeutic Resistance in Men with Metastatic Castration- Resistant Prostate Cancer 5c. PROGRAM

Estimating urban flood risk - uncertainty in design criteria

NASA Astrophysics Data System (ADS)

Newby, M.; Franks, S. W.; White, C. J.

2015-06-01

The design of urban stormwater infrastructure is generally performed assuming that climate is static. For engineering practitioners, stormwater infrastructure is designed using a peak flow method, such as the Rational Method as outlined in the Australian Rainfall and Runoff (AR&R) guidelines and estimates of design rainfall intensities. Changes to Australian rainfall intensity design criteria have been made through updated releases of the AR&R77, AR&R87 and the recent 2013 AR&R Intensity Frequency Distributions (IFDs). The primary focus of this study is to compare the three IFD sets from 51 locations Australia wide. Since the release of the AR&R77 IFDs, the duration and number of locations for rainfall data has increased and techniques for data analysis have changed. Updated terminology coinciding with the 2013 IFD release has also resulted in a practical change to the design rainfall. For example, infrastructure that is designed for a 1 : 5 year ARI correlates with an 18.13% AEP, however for practical purposes, hydraulic guidelines have been updated with the more intuitive 20% AEP. The evaluation of design rainfall variation across Australia has indicated that the changes are dependent upon location, recurrence interval and rainfall duration. The changes to design rainfall IFDs are due to the application of differing data analysis techniques, the length and number of data sets and the change in terminology from ARI to AEP. Such changes mean that developed infrastructure has been designed to a range of different design criteria indicating the likely inadequacy of earlier developments to the current estimates of flood risk. In many cases, the under-design of infrastructure is greater than the expected impact of increased rainfall intensity under climate change scenarios.

Argon Intercalibration Pipette System (APIS): Smoking from the Same Pipe

NASA Astrophysics Data System (ADS)

Turrin, B. D.; Swisher, C. C., III; Hemming, S. R.; Renne, P. R.; Deino, A. L.; Hodges, K. V.; Van Soest, M. C.; Heizler, M. T.

2014-12-01

40Ar/39Ar age inter-calibration experiments, conducted as part of the US NSF sponsored EARTHTIME initiative, (http://www.earth-time.org), using two of the most commonly used 40Ar/39Ar mineral standards, Fish Canyon (FC, ~28.2 Ma) and Alder Creek (AC, ~1.2 Ma) sanidines, have revealed significant inter-laboratory inconsistencies. The reported ages for the AC sanidines range from 1.173 to 1.200 Ma (FC 28.02) (±~2%), ~4 times greater than the reported precision. These experiments have caused the 40Ar/39Ar community to scrutinize procedures and several informal lab intercalibrations have been conducted among different labs. This exercise is leading to better agreement, but discrepancies remain that need to be addressed. In an effort to isolate the cause(s) of these inconsistencies, two Argon Inter-calibration Pipette System (APIS) were designed and constructed. Each consists of three gas canisters; one contains atmospheric Ar, while the other two contain artificial gas mixtures with 40Ar/39Ar ratios similar to those of FC and AC. Each canister has 4x10-10 moles of 40Ar, is equipped with 0.1, 0.2 and 0.4 cc pipettes, and can deliver gas volumes from 0.1-0.7 cc. All volumes were determined manometrically to 0.4% or better and then filled to uniform pressure with Ar standard gases. This experimental design eliminates sample heterogeneity, leaving only interlaboratory variations in gas purification, data reduction, and isotopic measurement as potential sources of interlaboratory calibration discrepancies. APIS-1 was designated as a traveling unit that is brought to participating labs. APIS-2 is the reserve/master standard. Currently, APIS-1 is in its early stages in the voyage and has been to three labs (Rutgers, LDEO, and New Mexico Tech) as of this writing. The interlaboratory comparisons are ongoing, and will include ASU, BGC, Univ. of Wisconsin, and Oregon State University, plus additional laboratories of opportunity. A progress report will be presented at AGU.

An augmented reality system validation for the treatment of cockroach phobia.

PubMed

Bretón-López, Juani; Quero, Soledad; Botella, Cristina; García-Palacios, Azucena; Baños, Rosa Maria; Alcañiz, Mariano

2010-12-01

Augmented reality (AR) is a new technology in which various virtual elements are incorporated into the user's perception of the real world. The most significant aspect of AR is that the virtual elements add relevant and helpful information to the real scene. AR shares some important characteristics with virtual reality as applied in clinical psychology. However, AR offers additional features that might be crucial for treating certain problems. An AR system designed to treat insect phobia has been used for treating phobia of small animals, and positive preliminary data about the global efficacy of the system have been obtained. However, it is necessary to determine the capacity of similar AR systems and their elements that are designed to evoke anxiety in participants; this is achieved by testing the correspondence between the inclusion of feared stimuli and the induction of anxiety. The objective of the present work is to validate whether the stimuli included in the AR-Insect Phobia system are capable of inducing anxiety in six participants diagnosed with cockroach phobia. Results support the adequacy of each element of the system in inducing anxiety in all participants.

Composite Yb:YAG/SiC-prism thin disk laser.

PubMed

Newburgh, G A; Michael, A; Dubinskii, M

2010-08-02

We report the first demonstration of a Yb:YAG thin disk laser wherein the gain medium is intracavity face-cooled through bonding to an optical quality SiC prism. Due to the particular design of the composite bonded Yb:YAG/SiC-prism gain element, the laser beam impinges on all refractive index interfaces inside the laser cavity at Brewster's angles. The laser beam undergoes total internal reflection (TIR) at the bottom of the Yb(10%):YAG thin disk layer in a V-bounce cavity configuration. Through the use of TIR and Brewster's angles, no optical coatings, either anti-reflective (AR) or highly reflective (HR), are required inside the laser cavity. In this first demonstration, the 936.5-nm diode pumped laser performed with approximately 38% slope efficiency at 12 W of quasi-CW (Q-CW) output power at 1030 nm with a beam quality measured at M(2) = 1.5. This demonstration opens up a viable path toward novel thin disk laser designs with efficient double-sided room-temperature heatsinking via materials with the thermal conductivity of copper on both sides of the disk.

Genetic structure and variability of virus populations in cross-protected grapevines superinfected by Grapevine fanleaf virus.

PubMed

Vigne, Emmanuelle; Marmonier, Aurélie; Komar, Véronique; Lemaire, Olivier; Fuchs, Marc

2009-09-01

Recombination was assessed in a vineyard site in which grapevines cross-protected with mild strains GHu of Grapevine fanleaf virus (GFLV) or Ta of Arabis mosaic virus (ArMV) were superinfected with GFLV field isolates following transmission by the nematode vector Xiphinema index. The genetic structure and variability within RNA2 of isolates from grapevines co-infected with GFLV field isolates and either GFLV-GHu or ArMV-Ta were characterized to identify intra- and interspecies recombinants. Sequence analysis and phylogenetic relationships inferred intraspecies recombination among GFLV field isolates but not between field isolates and GFLV-GHu. SISCAN analysis confirmed a mosaic structure for two GFLV field isolates for which recombination sites were located in the movement protein and coat protein genes. One of the recombinants was found in eight grapevines that were in close spatial proximity within the vineyard site, suggesting its transmission by X. index. No interspecies recombination was detected between GFLV field isolates and ArMV-Ta. Altogether, our findings suggest that mild protective strains GFLV-GHu and ArMV-Ta did not assist the emergence of viable recombinants to detectable level during a 12-year cross-protection trial. To our knowledge, this is the first extensive characterization of the genetic structure and variability of virus isolates in cross-protected plants.

Localized etching of an insulator film coated on a copper wire using an atmospheric-pressure microplasma jet.

PubMed

Yoshiki, Hiroyuki

2007-04-01

Atmospheric-pressure microplasma jets (APmicroPJs) of Ar and ArO(2) gases were generated from the tip of a stainless steel surgical needle having outer and inner diameters of 0.4 and 0.2 mm, respectively, with a rf excitation of 13.56 MHz. The steel needle functions both as a powered electrode and a gas nozzle. The operating power is 1.2-6 W and the corresponding peak-to-peak voltage Vp.p. is about 1.5 kV. The APmicroPJ was applied to the localized etching of a polyamide-imide insulator film (thickness of 10 microm) of a copper winding wire of 90 microm diameter. The insulator film around the copper wire was completely removed by the irradiated plasma from a certain direction without fusing the wire. The removal time under the Ar APmicroPJ irradiation was only 3 s at a rf power of 4 W. Fluorescence microscopy and scanning electron microscope images reveal that good selectivity of the insulator film to the copper wire was achieved. In the case of ArO(2) APmicroPJ irradiation with an O(2) concentration of 10% or more, the removed copper surface was converted to copper monoxide CuO.

AR4VI: AR as an Accessibility Tool for People with Visual Impairments

PubMed Central

Coughlan, James M.; Miele, Joshua

2017-01-01

Although AR technology has been largely dominated by visual media, a number of AR tools using both visual and auditory feedback have been developed specifically to assist people with low vision or blindness – an application domain that we term Augmented Reality for Visual Impairment (AR4VI). We describe two AR4VI tools developed at Smith-Kettlewell, as well as a number of pre-existing examples. We emphasize that AR4VI is a powerful tool with the potential to remove or significantly reduce a range of accessibility barriers. Rather than being restricted to use by people with visual impairments, AR4VI is a compelling universal design approach offering benefits for mainstream applications as well. PMID:29303163

AR4VI: AR as an Accessibility Tool for People with Visual Impairments.

PubMed

Coughlan, James M; Miele, Joshua

2017-10-01

Although AR technology has been largely dominated by visual media, a number of AR tools using both visual and auditory feedback have been developed specifically to assist people with low vision or blindness - an application domain that we term Augmented Reality for Visual Impairment (AR4VI). We describe two AR4VI tools developed at Smith-Kettlewell, as well as a number of pre-existing examples. We emphasize that AR4VI is a powerful tool with the potential to remove or significantly reduce a range of accessibility barriers. Rather than being restricted to use by people with visual impairments, AR4VI is a compelling universal design approach offering benefits for mainstream applications as well.

Laser Evaporation Studies.

DTIC Science & Technology

1987-10-01

characterized to understand the ef- dependent refractive-index, ambient sensitivity due to fects of the laser evaporation conditions on the struc- adsorption of...or Ar-coated ZnSe crystalline structure in thin films Pulsed laser-assisted dep- osition is one such emerging technique which has a unique...needed to pre% ent satura- plates of ZnSe. NaCI. GaAs. and Ge. which when used in tion of the detector arraN. ,arious combinations proided incremental

Innovative Facet Passivation for High-Brightness Laser Diodes

DTIC Science & Technology

2016-02-05

and anti-reflection (AR) coatings are deposited after cleaving. Edge- emitting laser diodes emit very high optical powers from small emission areas, as...SECURITY CLASSIFICATION OF: The objective of this effort is to increase the power of low fill-factor (20%) laser diode (LD) bars from the present...2012 16-Nov-2015 Approved for Public Release; Distribution Unlimited Final Report: Innovative Facet Passivation for High-Brightness Laser Diodes The

Reliability-Centered Maintenance

DTIC Science & Technology

1978-12-29

the pack through a flow-control valve and is cooled and dehumidified by a heat exchanger and the turbine of an air-cycle refrigeration ma- chine. The...dirt, moisture, and heat are the most susceptible to corrosion, and properly applied and maintained protective coatings are necessary to prevent...LFM’TNT i RCJL, ’A~r I ARLCA & WORK JNI- N UMUL R, United Airlines San Francisco International Airport San Francisco, Ca 94128 Office of Assistant

32 CFR 1280.5 - Procedures. 1

Code of Federal Regulations, 2012 CFR

2012-07-01

... Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS... Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim arose... Staff Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim...

32 CFR 1280.5 - Procedures. 1

Code of Federal Regulations, 2011 CFR

2011-07-01

... Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS... Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim arose... Staff Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim...

32 CFR 1280.5 - Procedures. 1

Code of Federal Regulations, 2010 CFR

2010-07-01

... Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS... Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim arose... Staff Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim...

32 CFR 1280.5 - Procedures. 1

Code of Federal Regulations, 2013 CFR

2013-07-01

... Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS... Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim arose... Staff Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim...

32 CFR 1280.5 - Procedures. 1

Code of Federal Regulations, 2014 CFR

2014-07-01

... Defense Other Regulations Relating to National Defense DEFENSE LOGISTICS AGENCY MISCELLANEOUS... Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim arose... Staff Judge Advocate designated in AR 27-20, appendix F, as the Area Claims Authority where the claim...

Demonstration of a Groundwater Age Determination Using 39Ar in Support of a Multi-Tracer Groundwater Analysis of Wells in Fresno, CA

NASA Astrophysics Data System (ADS)

Wurstner White, S.; Brandenberger, J. M.; Kulongoski, J. T.; Aalseth, C.; Williams, R. M.; Mace, E. K.; Humble, P.; Seifert, A.; Cloutier, J. M.

2015-12-01

Argon-39 has a half-life of 269 years, making it an ideal tracer for groundwater dating in the age range of 50-1000 years. In September 2014, two production wells within the San Joaquin Valley Aquifer System, located in Fresno, CA were sampled and analyzed for a suite of inorganic and organic contaminants and isotopic constituents. The radiotracers 3H (< 50 years) and 14C (> 1000 years) are routinely measured as part of the U. S. Geological Survey (USGS) National Water Quality Assessment (NAWQA) Enhanced Trends Network project. Adding 39Ar to the suite of tracers provides age data in the intermediate range to refine the groundwater age distribution of mixed waters and establishes groundwater residence times and flow rates. Characterizing the groundwater recharge and flow rate is of particular interest at these wells for determining the sources and movement of contaminants in groundwater, particularly nitrate, DBCP, and perchlorate. The sampled wells were pumped and purged. The sample collection for the 39Ar measurements required extracting the dissolved gases from 3000-5000 L of groundwater using a membrane degasification system with a maximum flow rate of 50 gpm (11.4 m^3/hr). The membranes are plastic hollow fibers that are hydrophobic. The gas was collected in duplicate large aluminum coated plastic sample bags. The gas was purified and then counted via direct beta counting using ultra-low background proportional counters loaded with a mixture of geologic Ar and methane to enhance the sensitivity for Ar measurements. The activity of 39Ar is 1.01 Bq/kg Ar, corresponding to an abundance of 0.808 ppq. The estimated absolute ages of the samples from the two groundwater wells were 23.3 and 27.0 percent of modern Ar. The comparison of the groundwater residence times determined using the suite of radiotracers (3H, 39Ar, and 14C) highlighted the value of knowing the intermediate age of groundwater when determining contaminant fate and transport pathways.

Department of the Army Justification of Estimates for FY 1990/FY 1991 Biennial Budget Submitted to Congress January 1989. Procurement Appropriations-Construction Program

DTIC Science & Technology

1989-01-01

DATZ. An exemption to requirements of in eccnomic analysis .s :equested in icccrance with provisions AR 1,-28, Para. - 3d (3). Regulat.o references axe...provisions of XR 1I-28 Para !- 3d (3). :"gloos are required by AR 190-111, Ch. 4 and DOD 5100.76-M. Ch. 4-& 5. 12. SUPPLEMNTAL DATA: A. sti.mated Design...rdance witn AR ll-23, Para. D- 3d (2 Ths orolecm .z eu~_ - compiv .Ltn :onst=uction cr.:eria of AR0-_’:, ca. 4 and :CD 5i2 -.-. 21 4 A. Estzmated Design

Initial accomplishments of the Environmental Control and Life Support System (ECLSS) atmosphere revitalization (AR) predevelopment operational system test (POST) for the Space Station Freedom (SSF)

NASA Technical Reports Server (NTRS)

Dunn, Kevin H.; Bulgajewski, Peter J.

1992-01-01

Initial results of the integrated AR POST conducted by Boeing at Marshall Space Flight Center in 1992 are presented. The three baselined ECLSS Man Tended Capability AR assemblies were integrated and operated in a closed door chamber in which the internal atmosphere was monitored. The test provides a prerequisite checkout of the AR subsystem in preparation for longer duration tests in which the AR subsystem will be integrated with the Water Recovery Management subsystem. The integrated AR POST will serve as an early test bed to evaluate the integration of the space station ECLSS AR subsystem during design maturation.

Recent progress in the development of protein-protein interaction inhibitors targeting androgen receptor-coactivator binding in prostate cancer.

PubMed

Biron, Eric; Bédard, François

2016-07-01

The androgen receptor (AR) is a key regulator for the growth, differentiation and survival of prostate cancer cells. Identified as a primary target for the treatment of prostate cancer, many therapeutic strategies have been developed to attenuate AR signaling in prostate cancer cells. While frontline androgen-deprivation therapies targeting either the production or action of androgens usually yield favorable responses in prostate cancer patients, a significant number acquire treatment resistance. Known as the castration-resistant prostate cancer (CRPC), the treatment options are limited for this advanced stage. It has been shown that AR signaling is restored in CRPC due to many aberrant mechanisms such as AR mutations, amplification or expression of constitutively active splice-variants. Coregulator recruitment is a crucial regulatory step in AR signaling and the direct blockade of coactivator binding to AR offers the opportunity to develop therapeutic agents that would remain effective in prostate cancer cells resistant to conventional endocrine therapies. Structural analyses of the AR have identified key surfaces involved in protein-protein interaction with coregulators that have been recently used to design and develop promising AR-coactivator binding inhibitors. In this review we will discuss the design and development of small-molecule inhibitors targeting the AR-coactivator interactions for the treatment of prostate cancer. Copyright © 2015 Elsevier Ltd. All rights reserved.

Development of technique for AR coating and nickel and copper metallization of solar cells. FPS Project: Product development

NASA Technical Reports Server (NTRS)

Taylor, W.

1982-01-01

Printed nickel overplated with copper and applied on top of a predeposited silicon nitride antireflective coating system for metallizing solar cells was analyzed. The ESL D and E paste formulations, and the new formulations F, G, H, and D-1 were evaluated. The nickel thick films were tested after firing for stability in the cleaning and plating solutions used in the Vanguard-Pacific brush plating process. It was found that the films are very sensitive to the leaning and alkaline copper solutions. Less sensitivity was displayed to the neutral copper solution. Microscopic and SEM observations show segregation of frit at the silicon nitride thick film interface with loose frit residues after lifting off plated grid lines.

Etching and structure changes in PMMA coating under argon plasma immersion ion implantation

NASA Astrophysics Data System (ADS)

Kondyurin, Alexey; Bilek, Marcela

2011-06-01

A thin (120 nm) polymethylmethacrylate coating was treated by plasma immersion ion implantation with Ar using pulsed bias at 20 kV. Ellipsometry and FTIR spectroscopy and gel-fraction formation were used to detect the structure transformations as a function of ion fluence. The kinetics of etching, variations in refractive index and extinction coefficient in 400-1000 nm of wavelength, concentration changes in carbonyl, ether, methyl and methylene groups all as a function of ion fluence were analyzed. A critical ion fluence of 10 15 ions/cm 2 was observed to be a border between competing depolymerization and carbonization processes. Chemical reactions responsible for reorganization of the PMMA chemical structure under ion beam treatment are proposed.

The development of AR book for computer learning

NASA Astrophysics Data System (ADS)

Phadung, Muneeroh; Wani, Najela; Tongmnee, Nur-aiynee

2017-08-01

Educators need to provide the alternative educational tools to foster learning outcomes of students. By using AR technology to create exciting edutainment experiences, this paper presents how augmented reality (AR) can be applied in the education. This study aims to develop the AR book for tenth grade students (age 15-16) and evaluate its quality. The AR book was developed based on ADDIE framework processes to provide computer learning on software computer knowledge. The content was accorded with the current Thai education curriculum. The AR book had 10 pages in three topics (the first was "Introduction," the second was "System Software" and the third was "Application Software"). Each page contained markers that placed virtual objects (2D animation and video clip). The obtained data were analyzed in terms of average and standard deviation. The validity of multimedia design of the AR book was assessed by three experts in multimedia design. A five-point Likert scale was used and the values were X¯ =4 .84 , S.D. = 1.27 which referred to very high. Moreover, three content experts, who specialize in computer teaching, evaluated the AR book's validity. The values determined by the experts were X¯ =4 .69 , S.D. = 0.29 which referred to very high. Implications for future study and education are discussed.

Characterization and Application of a Planar Radio - Inductively-Coupled Plasma Source for the Production of Barrier Coatings.

NASA Astrophysics Data System (ADS)

Mahoney, Leonard Joseph

A planar radio-frequency (rf) inductively-coupled plasma (ICP) source is used to produce fluorocarbon discharges (CF_4/Ar) to fluorinate the surface of high-density polyethylene (HDPE). Using this system, concurrent studies of discharge characteristics, permeation properties of treated polymers and polymer surface characteristics are conducted to advance the use of plasma-fluorinated polymer surfaces as a barrier layer for automotive applications. Langmuir probes are used to determine spatial distribution of charged-particle and space-potential characteristics in Ar and CF_4/Ar discharges and to show the influence of the spatial distribution of the heating regions and the reactor boundaries on the discharge uniformity. Langmuir probes are also used to identify rf anisotropic drift motion of electrons in the heating regions of the source and transient high-energy electron features in pulsed discharges. These latter features allow pulsed ICP sources to be operated at low time-averaged powers that are necessary to treat thermally sensitive polymers. Fourier Transform Infrared (FITR) spectroscopy is used to measure the dissociation of fluorocarbon gases and to explore differences between pulsed- and continuous -power operation. Dissociation levels of CF_4 (50-85%) using pulsed-power operation are as high as that for continuous operation, even though the net time -averaged power is far less with pulsed operation. The result suggests that pulsed fluorocarbon discharges possess high concentrations of chemically-active species needed for rapid surface fluorination. A gravimetric permeation cup method is used to measure the permeation rate of test fuels through HDPE membranes, and electron spectroscopy for chemical analysis (ESCA) studies are performed to determine the stoichiometry and thickness of the barrier layer. From these studies we find that a 50-70 A thick, polar, fluoro-hydrocarbon over layer reduces the permeation of isooctane/toluene/methanol mixtures by a factor of 4. To increase the permeation resistance for automotive applications, this result points towards the deposition of a 1000 A thick fluoro-hydrocarbon barrier coating with stoichiometry and bond structures similar to the CF_4/Ar treated HDPE.

Application of the laser induced deflection (LID) technique for low absorption measurements in bulk materials and coatings

NASA Astrophysics Data System (ADS)

Triebel, W.; Mühlig, C.; Kufert, S.

2005-10-01

Precise absorption measurements of bulk materials and coatings upon pulsed ArF laser irradiation are presented using a compact experimental setup based on the laser induced deflection technique (LID). For absorption measurements of bulk materials the influence of pure bulk and pure surface absorption on the temperature and refractive index profile and thus for the probe beam deflection is analyzed in detail. The separation of bulk and surface absorption via the commonly used variation of the sample thickness is carried out for fused silica and calcium fluoride. The experimental results show that for the given surface polishing quality the bulk absorption coefficient of fused silica can be obtained by investigating only one sample. To avoid the drawback of different bulk and surface properties amongst a thickness series, we propose a strategy based on the LID technique to generally obtain surface and bulk absorption separately by investigating only one sample. Apart from measuring bulk absorption coefficients the LID technique is applied to determine the absorption of highly reflecting (HR) coatings on CaF2 substrates. Beside the measuring strategy the experimental results of a AlF3/LaF3 based HR coating are presented. In order to investigate a larger variety of coatings, including high transmitting coatings, a general measuring strategy based on the LID technique is proposed.

7 CFR 504.4 - Exemptions from user fee charges.

Code of Federal Regulations, 2012 CFR

2012-01-01

... OF AGRICULTURE USER FEES § 504.4 Exemptions from user fee charges. (a) USDA laboratories and ARS cooperators designated by the Curator of the ARS Patent Culture Collection are exempt from fee assessments. (b) The Curator of the ARS Patent Culture Collection is delegated the authority to approve and revoke...

7 CFR 504.4 - Exemptions from user fee charges.

Code of Federal Regulations, 2013 CFR

2013-01-01

... OF AGRICULTURE USER FEES § 504.4 Exemptions from user fee charges. (a) USDA laboratories and ARS cooperators designated by the Curator of the ARS Patent Culture Collection are exempt from fee assessments. (b) The Curator of the ARS Patent Culture Collection is delegated the authority to approve and revoke...

7 CFR 504.4 - Exemptions from user fee charges.

Code of Federal Regulations, 2010 CFR

2010-01-01

... OF AGRICULTURE USER FEES § 504.4 Exemptions from user fee charges. (a) USDA laboratories and ARS cooperators designated by the Curator of the ARS Patent Culture Collection are exempt from fee assessments. (b) The Curator of the ARS Patent Culture Collection is delegated the authority to approve and revoke...

7 CFR 504.4 - Exemptions from user fee charges.

Code of Federal Regulations, 2011 CFR

2011-01-01

... OF AGRICULTURE USER FEES § 504.4 Exemptions from user fee charges. (a) USDA laboratories and ARS cooperators designated by the Curator of the ARS Patent Culture Collection are exempt from fee assessments. (b) The Curator of the ARS Patent Culture Collection is delegated the authority to approve and revoke...

7 CFR 504.4 - Exemptions from user fee charges.

Code of Federal Regulations, 2014 CFR

2014-01-01

... OF AGRICULTURE USER FEES § 504.4 Exemptions from user fee charges. (a) USDA laboratories and ARS cooperators designated by the Curator of the ARS Patent Culture Collection are exempt from fee assessments. (b) The Curator of the ARS Patent Culture Collection is delegated the authority to approve and revoke...

Effect of glow DBD modulation on gas and thin film chemical composition: case of Ar/SiH4/NH3 mixture

NASA Astrophysics Data System (ADS)

Vallade, Julien; Bazinette, Remy; Gaudy, Laura; Massines, Françoise

2014-06-01

In recent years, atmospheric pressure plasma-enhanced chemical vapour deposition has been identified as a convenient way to deposit good quality thin films. With this type of process, where the gas mixture is injected on one side of the electrodes, the chemical composition of the gas evolves with the gas residence time in the plasma. The consequence is a possible gradient in the chemical composition over the thickness of in-line coatings. The present work shows that the modulation of the plasma with a square signal significantly reduces this gradient while the drawback of low growth rate is avoided by increasing the discharge power. This study deals with plane/plane glow dielectric barrier discharges (DBDs) in an Ar/NH3/SiH4 gas mixture to make thin films. The 50 kHz discharge power of the glow DBD was varied by increasing voltage and modulating excitation. The impact on (i) the plasma development was observed through emission spectroscopy and (ii) the thin film coating through Fourier transform infrared measurements. It is shown that the modulation significantly decreases the time and the energy needed to achieve stable chemistry, enhances secondary chemistry and limits disturbance induced by impurities because of a slower decrease of SiH4 concentration and thus a higher ratio of SiH4/impurities, all very important points for in-line AP-PECVD development. When the growth rate is limited by diffusion, coating growth continues when the discharge is off, so long as there is a precursor gradient between the surface and the gas bulk. A higher discharge power steepens this gradient, which enhances diffusion from the bulk and thus growth rate.

The structure, surface topography and mechanical properties of Si-C-N films fabricated by RF and DC magnetron sputtering

NASA Astrophysics Data System (ADS)

Shi, Zhifeng; Wang, Yingjun; Du, Chang; Huang, Nan; Wang, Lin; Ning, Chengyun

2011-12-01

Silicon carbon nitride thin films were deposited on Co-Cr alloy under varying deposition conditions such as sputtering power and the partial pressure ratio of N2 to Ar by radio frequency and direct current magnetron sputtering techniques. The chemical bonding configurations, surface topography and hardness were characterized by means of X-ray photoelectron spectroscopy, atomic force microscopy and nano-indentation technique. The sputtering power exhibited important influence on the film composition, chemical bonding configurations and surface topography, the electro-negativity had primary effects on chemical bonding configurations at low sputtering power. A progressive densification of the film microstructure occurring with the carbon fraction was increased. The films prepared by RF magnetron sputtering, the relative content of the Si-N bond in the films increased with the sputtering power increased, and Si-C and Si-Si were easily detachable, and C-O, N-N and N-O on the film volatile by ion bombardment which takes place very frequently during the film formation process. With the increase of sputtering power, the films became smoother and with finer particle growth. The hardness varied between 6 GPa and 11.23 GPa depending on the partial pressure ratio of N2 to Ar. The tribological characterization of Co-Cr alloy with Si-C-N coating sliding against UHMWPE counter-surface in fetal bovine serum, shows that the wear resistance of the Si-C-N coated Co-Cr alloy/UHMWPE sliding pair show much favourable improvement over that of uncoated Co-Cr alloy/UHMWPE sliding pair. This study is important for the development of advanced coatings with tailored mechanical and tribological properties.

Development of Ni-based multilayers for future focusing soft gamma ray telescopes

NASA Astrophysics Data System (ADS)

Girou, David A.; Massahi, Sonny; Sleire, Erlend K.; Jakobsen, Anders C.; Christensen, Finn E.

2015-09-01

Ni-based multilayers are a possible solution to extend the upper energy range of hard X-ray focusing telescopes currently limited at ≈79:4 keV by the Pt-K absorption edge. In this study 10 bilayers multilayers with a constant bilayer thickness were coated with the DC magnetron sputtering facility at DTU Space, characterized at 8 keV using X-ray reectometry and fitted using the IMD software. Ni/C multilayers were found to have a mean interface roughness ≈ 1:5 times lower than Ni/B4C multilayers. Reactive sputtering with ≈ 76% of Ar and ≈ 24% of N2 reduced the mean interface roughness by a factor of ≈ 1:7. It also increased the coating rate of C by a factor of ≈ 3:1 and lead to a coating process going ≈ 1:6 times faster. Honeycomb collimation proved to limit the increase in mean interface roughness when the bilayer thickness increases at the price of a coating process going ≈ 1:9 times longer than with separator plates. Finally a Ni/C 150 bilayers depth-graded mutilayer was coated with reactive sputtering and honeycomb collimation and then characterized from 10 keV to 150 keV. It showed 10% reectance up to 85 keV.

Formation of Cr2O3 Diffusion Barrier Between Cr-Contained Stainless Steel and Cold-Sprayed Ni Coatings at High Temperature

NASA Astrophysics Data System (ADS)

Xu, Ya-Xin; Luo, Xiao-Tao; Li, Cheng-Xin; Yang, Guan-Jun; Li, Chang-Jiu

2016-02-01

A novel approach to prepare a coating system containing an in situ grown Cr2O3 diffusion barrier between a nickel top layer and 310SS was reported. Cold spraying was employed to deposit Ni(O) interlayer and top nickel coating on the Cr-contained stainless steel substrate. Ni(O) feedstock was prepared by mechanical alloying of pure nickel powders in ambient atmosphere, acting as an oxygen provider. The post-spray annealing was adopted to grow in situ Cr2O3 layer between the substrate and nickel coating. The results revealed that the diffusible oxygen can be introduced into nickel powders by mechanical alloying. The oxygen content increases to 3.25 wt.% with the increase of the ball milling duration to 8 h, while Ni(O) powders maintain a single phase of Ni. By annealing the sample in Ar atmosphere at 900 °C, a continuous Cr2O3 layer of 1-2 μm thick at the interface between 310SS and cold-sprayed Ni coating is formed. The diffusion barrier effect evaluation by thermal exposure at 750 °C shows that the Cr2O3 oxide layer effectively suppresses the outward diffusion of Fe and Cr in the substrate effectively.

Microstructure evolution of a ZrC coating layer in TRISO particles during high-temperature annealing

NASA Astrophysics Data System (ADS)

Kim, Daejong; Chun, Young Bum; Ko, Myeong Jin; Lee, Hyeon-Geun; Cho, Moon-Sung; Park, Ji Yeon; Kim, Weon-Ju

2016-10-01

The influence of high-temperature annealing on the microstructure of zirconium carbide (ZrC) was investigated in relation to its application as a coating layer of a nuclear fuel in a very high temperature gas cooled reactor. ZrC was deposited as a constituent coating layer of TRISO coated particles by a fluidized bed chemical vapor deposition method using a ZrCl4-CH4-Ar-H2 system. The grain growth of ZrC during high-temperature annealing was strongly influenced by the co-deposition of free carbon. Sub-stoichiometric ZrC coatings have experienced a significant grain growth during high-temperature annealing at 1800 °C and 1900 °C for 1 h. On the other hand, a dual phase of stoichiometric ZrC and free carbon experienced little grain growth. It was revealed that the free carbon of the as-deposited ZrC was primarily distributed within the ZrC grains but was redistributed to the grain boundaries after annealing. Consequently, carbon at the grain boundary retarded the grain growth of ZrC. Electron backscatter diffraction (EBSD) results showed that as-deposited ZrC had (001) a preferred orientation that kept its favored direction after significant grain growth during annealing. The hardness slightly decreased as the grain growth progressed.

Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances.

PubMed

Leung, Tsz Wing; Li, Roger Wing-Hong; Kee, Chea-Su

2017-01-01

To evaluate the optical performance of blue-light filtering spectacle lenses and investigate whether a reduction in blue light transmission affects visual performance and sleep quality. Experiment 1: The relative changes in phototoxicity, scotopic sensitivity, and melatonin suppression of five blue-light filtering plano spectacle lenses were calculated based on their spectral transmittances measured by a spectrophotometer. Experiment 2: A pseudo-randomized controlled study was conducted to evaluate the clinical performance of two blue-light filtering spectacle lenses (BF: blue-filtering anti-reflection coating; BT: brown-tinted) with a regular clear lens (AR) serving as a control. A total of eighty computer users were recruited from two age cohorts (young adults: 18-30 yrs, middle-aged adults: 40-55 yrs). Contrast sensitivity under standard and glare conditions, and colour discrimination were measured using standard clinical tests. After one month of lens wear, subjective ratings of lens performance were collected by questionnaire. All tested blue-light filtering spectacle lenses theoretically reduced the calculated phototoxicity by 10.6% to 23.6%. Although use of the blue-light filters also decreased scotopic sensitivity by 2.4% to 9.6%, and melatonin suppression by 5.8% to 15.0%, over 70% of the participants could not detect these optical changes. Our clinical tests revealed no significant decrease in contrast sensitivity either with (95% confidence intervals [CI]: AR-BT [-0.05, 0.05]; AR-BF [-0.05, 0.06]; BT-BF [-0.06, 0.06]) or without glare (95% CI: AR-BT [-0.01, 0.03]; AR-BF [-0.01, 0.03]; BT-BF [-0.02, 0.02]) and colour discrimination (95% CI: AR-BT [-9.07, 1.02]; AR-BF [-7.06, 4.46]; BT-BF [-3.12, 8.57]). Blue-light filtering spectacle lenses can partially filter high-energy short-wavelength light without substantially degrading visual performance and sleep quality. These lenses may serve as a supplementary option for protecting the retina from potential blue-light hazard. ClinicalTrials.gov NCT02821403.

U.S. Navy Statutory Monitoring of Tributyltin in Selected U.S. Harbors

DTIC Science & Technology

1990-06-01

U.S. Navy and has very little commercial and private use. Tributyltin loading from Navy ships painted with TBT antifoulants was closely correlated (r 2...evaluated major tributyltin ( TBT ) sources ar well as tidal, vertical, and spatial variability (Valkirs et al., 1986; Seligman et al., 1986; Seligman et al... tributyltin antifouling paints to deter- mine both their efficacy and environmental concentration resulting from use of these TBT antifouling coatings

Targeting the minor pocket of C5aR for the rational design of an oral allosteric inhibitor for inflammatory and neuropathic pain relief.

PubMed

Moriconi, Alessio; Cunha, Thiago M; Souza, Guilherme R; Lopes, Alexandre H; Cunha, Fernando Q; Carneiro, Victor L; Pinto, Larissa G; Brandolini, Laura; Aramini, Andrea; Bizzarri, Cinzia; Bianchini, Gianluca; Beccari, Andrea R; Fanton, Marco; Bruno, Agostino; Costantino, Gabriele; Bertini, Riccardo; Galliera, Emanuela; Locati, Massimo; Ferreira, Sérgio H; Teixeira, Mauro M; Allegretti, Marcello

2014-11-25

Chronic pain resulting from inflammatory and neuropathic disorders causes considerable economic and social burden. Pharmacological therapies currently available for certain types of pain are only partially effective and may cause severe adverse side effects. The C5a anaphylatoxin acting on its cognate G protein-coupled receptor (GPCR), C5aR, is a potent pronociceptive mediator in several models of inflammatory and neuropathic pain. Although there has long been interest in the identification of C5aR inhibitors, their development has been complicated, as for many peptidomimetic drugs, mostly by poor drug-like properties. Herein, we report the de novo design of a potent and selective C5aR noncompetitive allosteric inhibitor, DF2593A, guided by the hypothesis that an allosteric site, the "minor pocket," previously characterized in CXC chemokine receptors-1 and -2, is functionally conserved in the GPCR class. In vitro, DF2593A potently inhibited C5a-induced migration of human and rodent neutrophils. In vivo, oral administration of DF2593A effectively reduced mechanical hyperalgesia in several models of acute and chronic inflammatory and neuropathic pain, without any apparent side effects. Mechanical hyperalgesia after spared nerve injury was also reduced in C5aR(-/-) mice compared with WT mice. Furthermore, treatment of C5aR(-/-) mice with DF2593A did not produce any further antinociceptive effect compared with C5aR(-/-) mice treated with vehicle. The successful medicinal chemistry strategy confirms that a conserved minor pocket is amenable for the rational design of selective inhibitors and the pharmacological results support that the allosteric blockade of the C5aR represents a highly promising therapeutic approach to control chronic inflammatory and neuropathic pain.

Secondary Electron Emission Yields

NASA Technical Reports Server (NTRS)

Krainsky, I.; Lundin, W.; Gordon, W. L.; Hoffman, R. W.

1981-01-01

The secondary electron emission (SEE) characteristics for a variety of spacecraft materials were determined under UHV conditions using a commercial double pass CMA which permits sequential Auger electron electron spectroscopic analysis of the surface. The transparent conductive coating indium tin oxide (ITO) was examined on Kapton and borosilicate glass and indium oxide on FED Teflon. The total SEE coefficient ranges from 2.5 to 2.6 on as-received surfaces and from 1.5 to 1.6 on Ar(+) sputtered surfaces with 5 nm removed. A cylindrical sample carousel provides normal incidence of the primary beam as well as a multiple Faraday cup measurement of the approximately nA beam currents. Total and true secondary yields are obtained from target current measurements with biasing of the carousel. A primary beam pulsed mode to reduce electron beam dosage and minimize charging of insulating coatings was applied to Mg/F2 coated solar cell covers. Electron beam effects on ITO were found quite important at the current densities necessary to do Auger studies.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture.

PubMed

Karthikeya Sharma, T

2015-11-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine's performance within the range studied.

Performance and emission characteristics of the thermal barrier coated SI engine by adding argon inert gas to intake mixture

PubMed Central

Karthikeya Sharma, T.

2014-01-01

Dilution of the intake air of the SI engine with the inert gases is one of the emission control techniques like exhaust gas recirculation, water injection into combustion chamber and cyclic variability, without scarifying power output and/or thermal efficiency (TE). This paper investigates the effects of using argon (Ar) gas to mitigate the spark ignition engine intake air to enhance the performance and cut down the emissions mainly nitrogen oxides. The input variables of this study include the compression ratio, stroke length, and engine speed and argon concentration. Output parameters like TE, volumetric efficiency, heat release rates, brake power, exhaust gas temperature and emissions of NOx, CO2 and CO were studied in a thermal barrier coated SI engine, under variable argon concentrations. Results of this study showed that the inclusion of Argon to the input air of the thermal barrier coated SI engine has significantly improved the emission characteristics and engine’s performance within the range studied. PMID:26644918

An Update to the EARTHTIME Argon Intercalibration Pipette System (APIS): Smoking from the Same Pipe

NASA Astrophysics Data System (ADS)

Turrin, B. D.; Swisher, C. C., III; Hemming, S. R.; Renne, P. R.; Deino, A. L.; Hodges, K. V.; Van Soest, M. C.; Heizler, M. T.

2015-12-01

Background: An initial 40Ar/39Ar inter-calibration experiment, using two of the most commonly used 40Ar/39Ar mineral standards, Fish Canyon (FC, ~28.2 Ma) and Alder Creek (AC, ~1.2 Ma) sanidines, revealed significant inter-laboratory inconsistencies. The reported ages for the AC sanidines range from 1.173 to 1.200 Ma (FC 28.02) (±~2%), ~4 times greater than the reported precisions. These experiments have motivated the 40Ar/39Ar community to reevaluate procedures and subsequent informal lab intercalibrations experiments are in better agreement, but discrepancies remain that need to be addressed. Experiment: In an effort to isolate the causes of these inconsistencies, an Argon Intercalibration Pipette System (APIS) was designed and constructed. The APIS system consists of three gas canisters; one containing atmospheric Ar and the other two canisters contain 40Ar/39Ar ratios that represent FC and AC. The volumes of the pipettes, bulbs and manifold are determined to within 0.4% and both systems were initially filled to the same pressure with Ar standard gases. Each canister has 4x10-10 moles of 40Ar, is equipped with a 0.1, 0.2 and 0.4 cc pipettes and can deliver increments from 0.1-0.7 cc. APIS-1 was designated as the traveling unit that is brought to participating labs, APIS-2 is the reserve/master standard. Early Results and Impressions: APIS-1 has been to four labs (Rutgers, LDEO, New Mexico Tech, and BGC) and is heading to ASU. Early APIS experimental data indicate that the inter-laboratory 40Ar/39Ar age results can meet or exceed the EARTHTIME goal of ±1‰ precision. The inter-laboratory comparisons are ongoing, and will include additional laboratories of opportunity. Lastly, the development of additional mineral standards that "fill in" the age gaps between the existing mineral standards would significantly improve attempting to achieve interlaboratory agreement at the ±1‰ level

Decision Support System for Aquifer Recharge (AR) and Aquifer Storage and Recovery (ASR) Planning, Design, and Evaluation - Principles and Technical Basis

EPA Science Inventory

Aquifer recharge (AR) is a technical method being utilized to enhance groundwater resources through man-made replenishment means, such as infiltration basins and injections wells. Aquifer storage and recovery (ASR) furthers the AR techniques by withdrawal of stored groundwater at...

RECOMBINANT ANDROGEN RECEPTOR (AR) BINDING ACROSS VERTEBRATE SPECIES: COMPARISON OF BINDING OF ENVIRONMENTAL COMPOUNDS TO HUMAN, RAINBOW TROUT AND FATHEAD MINNOW AR.

EPA Science Inventory

In vitro screening assays designed to identify androgen mimics or antagonists typically use mammalian (rat, human) androgen receptors (AR). Although the amino acid sequences of receptors from nonmammalian vertebrates are not identical to the mammalian receptors, it is uncertain ...

A Framework for Designing Collaborative Learning Environments Using Mobile AR

ERIC Educational Resources Information Center

Cochrane, Thomas; Narayan, Vickel; Antonczak, Laurent

2016-01-01

Smartphones provide a powerful platform for augmented reality (AR). Using a smartphone's camera together with the built in GPS, compass, gyroscope, and touch screen enables the real world environment to be overlaid with contextual digital information. The creation of mobile AR environments is relatively simple, with the development of mobile AR…

Living Action Research in Course Design: Centering Participatory and Social Justice Principles and Practices

ERIC Educational Resources Information Center

Gardner, Morgan; Hammett, Roberta

2014-01-01

Action research (AR) courses provide openings in higher education to engage students, schools and communities in democratic and socially just ways within the contexts of research, classroom learning and broader social interactions. Such opportunities are strengthened when instructors design AR courses with the goal of enabling students to…

Discovery of novel aldose reductase inhibitors using a protein structure-based approach: 3D-database search followed by design and synthesis.

PubMed

Iwata, Y; Arisawa, M; Hamada, R; Kita, Y; Mizutani, M Y; Tomioka, N; Itai, A; Miyamoto, S

2001-05-24

Aldose reductase (AR) has been implicated in the etiology of diabetic complications. Due to the limited number of currently available drugs for the treatment of diabetic complications, we have carried out structure-based drug design and synthesis in an attempt to find new types of AR inhibitors. With the ADAM&EVE program, a three-dimensional database (ACD3D) was searched using the ligand binding site of the AR crystal structure. Out of 179 compounds selected through this search followed by visual inspection, 36 compounds were purchased and subjected to a biological assay. Ten compounds showed more than 40% inhibition of AR at a 15 microg/mL concentration. In a subsequent lead optimization, a series of analogues of the most active compound were synthesized based on the docking mode derived by ADAM&EVE. Many of these congeners exhibited higher activities compared to the mother compound. Indeed, the most potent, synthesized compound showed an approximately 20-fold increase in inhibitory activity (IC(50) = 0.21 vs 4.3 microM). Furthermore, a hydrophobic subsite was newly inferred, which would be useful for the design of inhibitors with improved affinity for AR.

β-Arrestin 1 and 2 differentially regulate heptahelical receptor signaling and trafficking

PubMed Central

Kohout, Trudy A.; Lin, Fang-Tsyr; Perry, Stephen J.; Conner, David A.; Lefkowitz, Robert J.

2001-01-01

The two widely coexpressed isoforms of β-arrestin (termed βarrestin 1 and 2) are highly similar in amino acid sequence. The β-arrestins bind phosphorylated heptahelical receptors to desensitize and target them to clathrin-coated pits for endocytosis. To better define differences in the roles of β-arrestin 1 and 2, we prepared mouse embryonic fibroblasts from knockout mice that lack one of the β-arrestins (βarr1-KO and βarr2-KO) or both (βarr1/2-KO), as well as their wild-type (WT) littermate controls. These cells were analyzed for their ability to support desensitization and sequestration of the β2-adrenergic receptor (β2-AR) and the angiotensin II type 1A receptor (AT1A-R). Both βarr1-KO and βarr2-KO cells showed similar impairment in agonist-stimulated β2-AR and AT1A-R desensitization, when compared with their WT control cells, and the βarr1/2-KO cells were even further impaired. Sequestration of the β2-AR in the βarr2-KO cells was compromised significantly (87% reduction), whereas in the βarr1-KO cells it was not. Agonist-stimulated internalization of the AT1A-R was only slightly reduced in the βarr1-KO but was unaffected in the βarr2-KO cells. In the βarr1/2-KO cells, the sequestration of both receptors was dramatically reduced. Comparison of the ability of the two β-arrestins to sequester the β2-AR revealed β-arrestin 2 to be 100-fold more potent than β-arrestin 1. Down-regulation of the β2-AR was also prevented in the βarr1/2-KO cells, whereas no change was observed in the single knockout cells. These findings suggest that sequestration of various heptahelical receptors is regulated differently by the two β-arrestins, whereas both isoforms are capable of supporting receptor desensitization and down-regulation. PMID:11171997

Stacking metal nano-patterns and fabrication of moth-eye structure

NASA Astrophysics Data System (ADS)

Taniguchi, Jun

2018-01-01

Nanoimprint lithography (NIL) can be used as a tool for three-dimensional nanoscale fabrication. In particular, complex metal pattern structures in polymer material are demanded as plasmonic effect devices and metamaterials. To fabricate of metallic color filter, we used silver ink and NIL techniques. Metallic color filter was composed of stacking of nanoscale silver disc patterns and polymer layers, thus, controlling of polymer layer thickness is necessary. To control of thickness of polymer layer, we used spin-coating of UV-curable polymer and NIL. As a result, ten stacking layers with 1000 nm layer thickness was obtained and red color was observed. Ultraviolet nanoimprint lithography (UV-NIL) is the most effective technique for mass fabrication of antireflection structure (ARS) films. For the use of ARS films in mobile phones and tablet PCs, which are touch-screen devices, it is important to protect the films from fingerprints and dust. In addition, as the nanoscale ARS that is touched by the hand is fragile, it is very important to obtain a high abrasion resistance. To solve these problems, a UV-curable epoxy resin has been developed that exhibits antifouling properties and high hardness. The high abrasion resistance ARS films are shown to withstand a load of 250 g/cm2 in the steel wool scratch test, and the reflectance is less than 0.4%.

Microstructural design of functionally graded coatings composed of suspension plasma sprayed hydroxyapatite and bioactive glass.

PubMed

Cattini, Andrea; Bellucci, Devis; Sola, Antonella; Pawłowski, Lech; Cannillo, Valeria

2014-04-01

Various bioactive glass/hydroxyapatite (HA) functional coatings were designed by the suspension plasma spraying (SPS) technique. Their microstructure, scratch resistance, and apatite-forming ability in a simulated body fluid (SBF) were compared. The functional coatings design included: (i) composite coating, that is, randomly distributed constituent phases; (ii) duplex coating with glass top layer onto HA layer; and (iii) graded coating with a gradual changing composition starting from pure HA at the interface with the metal substrate up to pure glass on the surface. The SPS was a suitable coating technique to produce all the coating designs. The SBF tests revealed that the presence of a pure glass layer on the working surface significantly improved the reactivity of the duplex and graded coatings, but the duplex coating suffered a relatively low scratch resistance because of residual stresses. The graded coating therefore provided the best compromise between mechanical reliability and apatite-forming ability in SBF. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 551-560, 2014. Copyright © 2013 Wiley Periodicals, Inc.

Characterization of mechanical properties and electrochemical behaviour in a Hank´s solution of 316L/Cr1- xAlxN system

NASA Astrophysics Data System (ADS)

Osorio, D. M.; Caicedo, J. C.; Aperador, W.; Benitez-Castro, A. M.; Giraldo-Betancur, A. L.; Muñoz-Saldaña, J.; Yañez-Limón, J. M.; Sanchez, O.; Zambrano, G.

2017-01-01

Cr1-xAlxN hard coatings were successfully deposited by R.F. reactive magnetron co-sputtering in an Ar/N2 gas mixture using chromium and aluminium targets on 316L stainless steel substrates. Crystallographic orientations associated to the Cr1-xAlxN FCC based in the conjugate complex of CrN and w-AlN phases, with ao=4.18Å lattice parameter for the ternary Cr1-xAlxN compound were identified by X-Ray diffraction. The thickness and roughness of the deposited coatings are 1.00±0.05nm and 2.65±0.6nm, respectively. The mechanical properties were determined by nanoindentation leading to a hardness of 27.8±2.6GPa and elastic modulus of 346GPa. The corrosion resistance of the coated 316L/Cr1-xAlxN system under simulated body fluid (SBF, Hank’s solution) was determined via electrochemical impedance spectroscopy. A reduction in the corrosion rate of 99% in relation to uncoated 316L stainless steel substrate was found by Tafel. Thus, these coatings seem to be excellent candidates to be used in biomedical applications.

Relationship Between Crystalline Structure and Hardness of Ti-Si-N-O Coatings Fabricated by dc Sputtering

NASA Astrophysics Data System (ADS)

García-González, Leandro; Hernández-Torres, Julián; Mendoza-Barrera, Claudia; Meléndez-Lira, Miguel; García-Ramírez, Pedro J.; Martínez-Castillo, Jaime; Sauceda, Ángel; Herrera-May, Agustin L.; Muñoz Saldaña, Juan; Espinoza-Beltrán, Francisco J.

2008-08-01

Ti-Si-N-O coatings were deposited on AISI D2 tool steel and silicon substrates by dc reactive magnetron co-sputtering using a target of Ti-Si with a constant area ratio of 0.2. The substrate temperature was 400 °C and reactive atmosphere of nitrogen and argon. For all samples, argon flow was maintained constant at 25 sccm, while the flow of the nitrogen was varied to analyze the structural changes related to chemical composition and resistivity. According to results obtained by x-ray diffraction and stoichiometry calculations by x-ray energy dispersive spectroscopy the Ti-Si-N-O coatings contain two solid solutions. The higher crystalline part corresponds to titanium oxynitrure. Hardness tests on the coatings were carried out using the indentation work model and the hardness value was determined. Finally, the values of hardness were corroborated by nanoindentation test, and values of Young’s modulus and elastic recovery were discussed. We concluded that F2TSN sample ( F Ar = 25 sccm, F N = 5 sccm, P = 200 W, and P W = 8.9 × 10-3 mbar) presented the greatest hardness and the lowest resistivity values, due to its preferential crystalline orientation.

Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon.

PubMed

Behzad, Kasra; Mat Yunus, Wan Mahmood; Talib, Zainal Abidin; Zakaria, Azmi; Bahrami, Afarin

2012-01-16

Porous silicon (PSi) layers were formed on a p-type Si wafer. Six samples were anodised electrically with a 30 mA/cm² fixed current density for different etching times. The samples were coated with a 50-60 nm gold layer and annealed at different temperatures under Ar flow. The morphology of the layers, before and after annealing, formed by this method was investigated by scanning electron microscopy (SEM). Photoacoustic spectroscopy (PAS) measurements were carried out to measure the thermal diffusivity (TD) of the PSi and Au/PSi samples. For the Au/PSi samples, the thermal diffusivity was measured before and after annealing to study the effect of annealing. Also to study the aging effect, a comparison was made between freshly annealed samples and samples 30 days after annealing.

Formation of silicon nanodots via ion beam sputtering of ultrathin gold thin film coatings on Si

PubMed Central

2011-01-01

Ion beam sputtering of ultrathin film Au coatings used as a physical catalyst for self-organization of Si nanostructures has been achieved by tuning the incident particle energy. This approach holds promise as a scalable nanomanufacturing parallel processing alternative to candidate nanolithography techniques. Structures of 11- to 14-nm Si nanodots are formed with normal incidence low-energy Ar ions of 200 eV and fluences above 2 × 1017 cm-2. In situ surface characterization during ion irradiation elucidates early stage ion mixing migration mechanism for nanodot self-organization. In particular, the evolution from gold film islands to the formation of ion-induced metastable gold silicide followed by pure Si nanodots formed with no need for impurity seeding. PMID:21711934

76 FR 28209 - Notice of Intent To Reestablish the National Genetic Resources Advisory Council, and Request for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-16

...-0321; Fasimile: (202) 720-6199. E-mail: [email protected]ars.usda.gov . FOR FURTHER INFORMATION CONTACT: J. Robert Burk, Designated Federal Official; Phone: (202) 720-8408; E-mail [email protected]ars.usda.gov... resource agriculture producers. Dated: April 5, 2011. Edward B. Knipling, Administrator, ARS. [FR Doc. 2011...

Fulfilling the "Missing Link" between University and Authentic Workplace in Teacher Training

ERIC Educational Resources Information Center

Mugaloglu, Ebru Zeynep; Doganca, Zerrin

2009-01-01

Purpose: This study aims to enable pre-service teachers to cooperate with teachers and to participate in solving classroom problems with the guidance of academic staff in an action research (AR) project. Design/methodology/approach: Eight pre-service teachers took an AR course and simultaneously participated in a collaborative AR project. While…

Analytic Validation of RNA In Situ Hybridization (RISH) for AR and AR-V7 Expression in Human Prostate Cancer

PubMed Central

Guedes, Liana B.; Morais, Carlos L.; Almutairi, Fawaz; Haffner, Michael C.; Zheng, Qizhi; Isaacs, John T.; Antonarakis, Emmanuel S.; Lu, Changxue; Tsai, Harrison; Luo, Jun; De Marzo, Angelo M.; Lotan, Tamara L.

2016-01-01

Purpose RNA expression of androgen receptor splice variants may be a biomarker of resistance to novel androgen deprivation therapies in castrate resistant prostate cancer (CRPC). We analytically validated an RNA in situ hybridization (RISH) assay for total AR and AR-V7 for use in formalin fixed paraffin embedded (FFPE) prostate tumors. Experimental Design We used prostate cell lines and xenografts to validate chromogenic RISH to detect RNA containing AR exon 1 (AR-E1, surrogate for total AR RNA species) and cryptic exon 3 (AR-CE3, surrogate for AR-V7 expression). RISH signals were quantified in FFPE primary tumors and CRPC specimens, comparing to known AR and AR-V7 status by immunohistochemistry and RT-PCR. Results The quantified RISH results correlated significantly with total AR and AR-V7 levels by RT-PCR in cell lines, xenografts and autopsy metastases. Both AR-E1 and AR-CE3 RISH signals were localized in nuclear punctae in addition to the expected cytoplasmic speckles. Compared to admixed benign glands, AR-E1 expression was significantly higher in primary tumor cells with a median fold increase of 3.0 and 1.4 in two independent cohorts (p<0.0001 and p=0.04, respectively). While AR-CE3 expression was detectable in primary prostatic tumors, levels were substantially higher in a subset of CRPC metastases and cell lines, and were correlated with AR-E1 expression. Conclusions RISH for AR-E1 and AR-CE3 is an analytically valid method to examine total AR and AR-V7 RNA levels in FFPE tissues. Future clinical validation studies are required to determine whether AR RISH is a prognostic or predictive biomarker in specific clinical contexts. PMID:27166397

Natural radionuclide mobility and its influence on U-Th-Pb dating of secondary minerals from the unsaturated zone at Yucca Mountain, Nevada

USGS Publications Warehouse

Neymark, L.A.; Amelin, Y.V.

2008-01-01

Extreme U and Pb isotope variations produced by disequilibrium in decay chains of 238U and 232Th are found in calcite, opal/chalcedony, and Mn-oxides occurring as secondary mineral coatings in the unsaturated zone at Yucca Mountain, Nevada. These very slowly growing minerals (mm my-1) contain excess 206Pb and 208Pb formed from excesses of intermediate daughter isotopes and cannot be used as reliable 206Pb/238U geochronometers. The presence of excess intermediate daughter isotopes does not appreciably affect 207Pb/235U ages of U-enriched opal/chalcedony, which are interpreted as mineral formation ages. Opal and calcite from outer (younger) portions of coatings have 230Th/U ages from 94.6 ?? 3.7 to 361.3 ?? 9.8 ka and initial 234U/238U activity ratios (AR) from 4.351 ?? 0.070 to 7.02 ?? 0.12, which indicate 234U enrichment from percolating water. Present-day 234U/238U AR is ???1 in opal/chalcedony from older portions of the coatings. The 207Pb/235U ages of opal/chalcedony samples range from 0.1329 ?? 0.0080 to 9.10 ?? 0.21 Ma, increase with microstratigraphic depth, and define slow long-term average growth rates of about 1.2-2.0 mm my-1, in good agreement with previous results. Measured 234U/238U AR in Mn-oxides, which pre-date the oldest calcite and opal/chalcedony, range from 0.939 ?? 0.006 to 2.091 ?? 0.006 and are >1 in most samples. The range of 87Sr/86Sr ratios (0.71156-0.71280) in Mn-oxides overlaps that in the late calcite. These data indicate that Mn-oxides exchange U and Sr with percolating water and cannot be used as a reliable dating tool. In the U-poor calcite samples, measured 206Pb/207Pb ratios have a wide range, do not correlate with Ba concentration as would be expected if excess Ra was present, and reach a value of about 1400, the highest ever reported for natural Pb. Calcite intergrown with opal contains excesses of both 206Pb and 207Pb derived from Rn diffusion and from direct ??-recoil from U-rich opal. Calcite from coatings devoid of opal/chalcedony contains 206Pb and 208Pb excesses, but no appreciable 207Pb excesses. Observed Pb isotope anomalies in calcite are explained by Rn-produced excess Pb. The Rn emanation may strongly affect 206Pb-238U ages of slow-growing U-poor calcite, but should be negligible for dating fast-growing U-enriched speleothem calcite.

Structured Analysis for the Logistic Support Analysis (LSA) Task and the Integrated Logistic Support (ILS) Element. Structured Analysis - ILS Assessment Element E11. Design Influence

DTIC Science & Technology

1989-01-01

format size of this report, the full identifying entry may well be forcibly shortened, thereby introducing the possibility of misunderstanding. Therefore...OF MATERIEL" 3d . "AR 570-9, "MANPOWER AND EQUIPMENT CONTROL - HOST NATION SUPPORT" 2. AR 700-9, "POLICIES OF THE ARMY LOGISTIC SYSTEM" 3. AR 700-82...PERSONNEL 4. TRAINING 5. SYSTEM SAFETY 6. HEALTH HAZARDS. TEE ASSESSMENT Or MANPRINT INFLUENCE ON DESIGNS IS ADDRESSED IN SIX (6) SPECIFIC AREAS IN

Using an action research process in pharmacy practice research--a cooperative project between university and internship pharmacies.

PubMed

Sørensen, Ellen Westh; Haugbølle, Lotte Stig

2008-12-01

Action research (AR) is a common research-based methodology useful for development and organizational changes in health care when participant involvement is key. However, AR is not widely used for research in the development of pharmaceutical care services in pharmacy practice. To disseminate the experience from using AR methodology to develop cognitive services in pharmacies by describing how the AR process was conducted in a specific study, and to describe the outcome for participants. The study was conducted over a 3-year period and run by a steering group of researchers, pharmacy students, and preceptors. The study design was based on AR methodology. The following data production methods were used to describe and evaluate the AR model: documentary analysis, qualitative interviews, and questionnaires. Experiences from using AR methodology and the outcome for participants are described. A set of principles was followed while the study, called the Pharmacy-University study, was being conducted. These principles are considered useful for designing future AR studies. Outcome for participating pharmacies was registered for staff-oriented and patient-oriented activities. Outcome for students was practice as project leaders and enhancement of clinical pharmacy-based skills. Outcome for researchers and the steering group conducting the study was in-depth knowledge of the status of pharmacies in giving advice to patient groups, and effective learning methods for students. Developing and implementing cognitive pharmaceutical services (CPS) involves wide-reaching changes that require the willingness of pharmacy and staff as well as external partners. The use of AR methodology creates a platform that supports raising the awareness and the possible inclusion of these partners. During this study, a set of tools was developed for use in implementing CPS as part of AR.

Space shuttle atmospheric revitalization subsystem/active thermal control subsystem computer program (users manual)

NASA Technical Reports Server (NTRS)

1973-01-01

A shuttle (ARS) atmosphere revitalization subsystem active thermal control subsystem (ATCS) performance routine was developed. This computer program is adapted from the Shuttle EC/LSS Design Computer Program. The program was upgraded in three noteworthy areas: (1) The functional ARS/ATCS schematic has been revised to accurately synthesize the shuttle baseline system definition. (2) The program logic has been improved to provide a more accurate prediction of the integrated ARS/ATCS system performance. Additionally, the logic has been expanded to model all components and thermal loads in the ARS/ATCS system. (3) The program is designed to be used on the NASA JSC crew system division's programmable calculator system. As written the new computer routine has an average running time of five minutes. The use of desk top type calculation equipment, and the rapid response of the program provides the NASA with an analytical tool for trade studies to refine the system definition, and for test support of the RSECS or integrated Shuttle ARS/ATCS test programs.

Electrostatic bonding of thin (cycle sine 3 mil) 7070 cover glass to Ta2O5 AR-coated thin (cycle sine 2 mil) silicon wafers and solar cells

NASA Technical Reports Server (NTRS)

Egelkrout, D. W.

1981-01-01

Electrostatic bonding of thin cover glass to thin solar cells was researched. Silicon solar cells, wafers, and Corning 7070 glass of from about 0.002" to about 0.003" in thickness were used in the investigation to establish optimum parameters for producing mechanically acceptable bonds while minimizing thermal stresses and resultant solar cell electrical parameter degradation.

Development of Ceramics with Highly Organized Microstructures

DTIC Science & Technology

2007-03-01

time for reviev AFRL- SR -AR-TR-08_00 6 8 gathering and maintaining the data needed, and completing and reviewing the collection of information. Send...formation the single crystal substrate was cleaned prior to sputter coating a 100 nm thick nickel seed layer on the polished surface. A positive photoresist...growth of the single crystal was accomplished without an interfacial layer and with no applied load. The main difference was Ba /Ti ratio of the starting

Characterization of nanoscopic calcium fluoride films

NASA Astrophysics Data System (ADS)

Rehmer, A.; Kemnitz, E.

2016-09-01

Nano metal fluorides are appropriate materials for different applications e.g. heterogeneous catalysis, ceramic materials for laser applications and antireflective layers on glass, respectively. An easy way to synthesize such nano metal fluorides is the fluorolytic sol-gel synthesis which was developed some few years ago for HS-AlF3 [1] and MgF2.[2] CaF2 exhibits similar optical properties as MgF2, and thus, is a promising candidate for antireflective (AR) coatings. That means, CaF2 exhibits a lower refractive index (n500 = 1.44) as compared to common soda lime glass (n500 = 1.53). Hence, we present an easy synthesis approach toward nanoscaled CaF2 sols to fabricate finally AR-CaF2 films by dip coating. Irrespective of the choice of the calcium precursor, the CaF2 films are porous in comparison to thin dense CaF2 films which are generated by physical vapor deposition. The characterization of CaF2 films was performed by different analytical methods like HR-SEM, XPS, EDX, EP (ellipsometric porosimetry), DLS (dynamic light scattering) and CA (contact angle measurement). Beside the good optical and mechanical properties, we have investigated the surface properties of CaF2 films on glass and silicon wafer e.g. surface morphology with elemental composition, open porosity, zeta potentials at the surfaces as well as the free energy of interaction between water and the CaF2 film.

Interacting with Visual Poems through AR-Based Digital Artwork

ERIC Educational Resources Information Center

Lin, Hao-Chiang Koong; Hsieh, Min-Chai; Liu, Eric Zhi-Feng; Chuang, Tsung-Yen

2012-01-01

In this study, an AR-based digital artwork called "Mind Log" was designed and evaluated. The augmented reality technique was employed to create digital artwork that would present interactive poems. A digital poem was generated via the interplay between a video film and a text-based poem. This artwork was created following a rigorous design flow,…

Using isotopes for design and monitoring of artificial recharge systems

USGS Publications Warehouse

Contributors: Hendriksson, N.; Kulongoski, J.T.; Massmann, G.; Newman, B.

2013-01-01

Over the past years, the IAEA has provided support to a number of Member States engaged in the implementation of hydrological projects dealing with the design and monitoring of artificial recharge ( A R ) systems, primarily situated in arid and semiarid regions. AR is defined as any engineered system designed to introduce water to, and store water in, underlying aquifers. Aquifer storage and recovery (ASR) is a specific type of AR used with the purpose of increasing groundwater resources. Different water management strategies have been tested under various geographical, hydrological and climatic regimes. However, the success of such schemes cannot easily be predicted, since many variables need to be taken into account in the early stages of every AR project.

The role of DAB2IP in androgen receptor activation during prostate cancer progression.

PubMed

Wu, K; Liu, J; Tseng, S-F; Gore, C; Ning, Z; Sharifi, N; Fazli, L; Gleave, M; Kapur, P; Xiao, G; Sun, X; Oz, O K; Min, W; Alexandrakis, G; Yang, C-R; Hsieh, C-L; Wu, H-C; He, D; Xie, D; Hsieh, J-T

2014-04-10

Altered androgen-receptor (AR) expression and/or constitutively active AR are commonly associated with prostate cancer (PCa) progression. Targeting AR remains a focal point for designing new strategy of PCa therapy. Here, we have shown that DAB2IP, a novel tumor suppressor in PCa, can inhibit AR-mediated cell growth and gene activation in PCa cells via distinct mechanisms. DAB2IP inhibits the genomic pathway by preventing AR nuclear translocation or phosphorylation and suppresses the non-genomic pathway via its unique functional domain to inactivate c-Src. Also, DAB2IP is capable of suppressing AR activation in an androgen-independent manner. In addition, DAB2IP can inhibit several AR splice variants showing constitutive activity in PCa cells. In DAB2IP(-/-) mice, the prostate gland exhibits hyperplastic epithelia, in which AR becomes more active. Consistently, DAB2IP expression inversely correlates with AR activation status particularly in recurrent or metastatic PCa patients. Taken together, DAB2IP is a unique intrinsic AR modulator in normal cells, and likely can be further developed into a therapeutic agent for PCa.

AR copy number and AR signaling-directed therapies in castration-resistant prostate cancer.

PubMed

Salvi, Samanta; Conteduca, Vincenza; Lolli, Cristian; Testoni, Sara; Casadio, Valentina; Zaccheroni, Andrea; Rossi, Lorena; Burgio, Salvatore Luca; Menna, Cecilia; Schepisi, Giuseppe; De Giorgi, Ugo

2017-11-22

Adaptive upregulation of androgen receptor (AR) is the most common event involved in the progression from hormone sensitive to castration-resistant prostate cancer (CRPC). AR signaling remains the main target of new AR signalling-directed therapies such as abiraterone and enzalutamide in CRPC patients. In this review, we discuss general mechanisms of resistance to AR-targeted therapies, with a focus on the role of AR copy number (CN). We reported methods and clinical applications of AR CN evaluation in tissue and liquid biopsy, thus to have a complete information regarding its role as predictive and prognostic biomarker. Outcomes of CRPC patients are reported to be highly variable as consequence of tumor heterogeneity. AR CN could contribute to patient selection and tumor monitoring in CRPC treated with new anti-cancer treatment as abiraterone and enzalutamide. Further studies to investigate AR CN effect to these agents and its potential combination with other prognostic or predictive clinical factors are necessary in the context of harmonized clinical trial design. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Mid-wavelength infrared unipolar nBp superlattice photodetector

NASA Astrophysics Data System (ADS)

Kazemi, Alireza; Myers, Stephen; Taghipour, Zahra; Mathews, Sen; Schuler-Sandy, Ted; Lee, Seunghyun; Cowan, Vincent M.; Garduno, Eli; Steenbergen, Elizabeth; Morath, Christian; Ariyawansa, Gamini; Scheihing, John; Krishna, Sanjay

2018-01-01

We report a Mid-Wavelength Infrared (MWIR) barrier photodetector based on the InAs/GaSb/AlSb type-II superlattice (T2SL) material system. The nBp design consists of a single unipolar barrier (InAs/AlSb SL) placed between a 4 μm thick p-doped absorber (InAs/GaSb SL) and an n-type contact layer (InAs/GaSb SL). At 80 K, the device exhibited a 50% cut-off wavelength of 5 μm, was fully turned-ON at zero bias and the measured QE was 50% (front side illumination with no AR coating) at 4.5 μm with a dark current density of 4.7 × 10-6 A/cm2 at Vb = 50 mV. At 150 K and Vb = 50 mV, the 50% cut-off wavelength increased to 5.3 μm, and the QE was 54% at 4.5 μm with a dark current of 5.0 × 10-4 A/cm2.

Establishment and Usability Evaluation of an Interactive AR Learning System on Conservation of Fish

ERIC Educational Resources Information Center

Lin, Hao-Chiang Koong; Hsieh, Min-Chai; Wang, Cheng-Hung; Sie, Zong-Yuan; Chang, Shei-Hsi

2011-01-01

In this study, we develop an interactive AR Learning System based on Augmented Reality and interactive touch-screen. The learning content knowledge is about conservation of fish in Taiwan. The system combines the game by the concept of AR book which allows children to learn about the importance of conservation of fish. A mechanism is designed to…

Learning Science Using AR Book: A Preliminary Study on Visual Needs of Deaf Learners

NASA Astrophysics Data System (ADS)

Megat Mohd. Zainuddin, Norziha; Badioze Zaman, Halimah; Ahmad, Azlina

Augmented Reality (AR) is a technology that is projected to have more significant role in teaching and learning, particularly in visualising abstract concepts in the learning process. AR is a technology is based on visually oriented technique. Thus, it is suitable for deaf learners since they are generally classified as visual learners. Realising the importance of visual learning style for deaf learners in learning Science, this paper reports on a preliminary study of on an ongoing research on problems faced by deaf learners in learning the topic on Microorganisms. Being visual learners, they have problems with current text books that are more text-based that graphic based. In this preliminary study, a qualitative approach using the ethnographic observational technique was used so that interaction with three deaf learners who are participants throughout this study (they are also involved actively in the design and development of the AR Book). An interview with their teacher and doctor were also conducted to identify their learning and medical problems respectively. Preliminary findings have confirmed the need to design and develop a special Augmented Reality Book called AR-Science for Deaf Learners (AR-SiD).

Plasma Radiofrequency Discharges as Cleaning Technique for the Removal of C-W Coatings

NASA Astrophysics Data System (ADS)

Cremona, A.; Vassallo, E.; Caniello, R.; Ghezzi, F.; Grosso, G.; Laguardia, L.

2013-06-01

Erosion of materials by chemical and physical sputtering is one of the most concern of plasma wall interaction in tokamaks. In divertor ITER-like tokamaks, where carbon and tungsten are planned to be used, hydrogenated C-W mixed compounds are expected to form by erosion, transport and re-deposition processes. The selection of these materials as divertor components involves lifetime and safety issues due to tritium retention in carbon co-deposits. In this paper a cleaning technique based on RF (13.56 MHz) capacitively coupled H2/Ar plasmas has been used to remove C-W mixed materials from test specimens. The dependence of the removal rate on the H2/Ar ratio and on the plasma pressure has been investigated by X-ray photoelectron spectroscopy, atomic force microscopy, profilometry as regards the solid phase and by Langmuir probe and optical emission spectroscopy as regards the plasma phase. The best result has been obtained with a H2/Ar ratio of 10/90 at a pressure of 1 Pa. An explanation based on a synergistic effect between physical sputtering due to energetic ions and chemical etching due to radicals, together with the pressure dependence of the ion energy distribution function, is given.

Optimizing the design and in vitro evaluation of bioreactive glucose oxidase-microspheres for enhanced cytotoxicity against multidrug resistant breast cancer cells.

PubMed

Cheng, Ji; Liu, Qun; Shuhendler, Adam J; Rauth, Andrew M; Wu, Xiao Yu

2015-06-01

Glucose oxidase (GOX) encapsulated in alginate-chitosan microspheres (GOX-MS) was shown in our previous work to produce reactive oxygen species (ROS) in situ and exhibit anticancer effects in vitro and in vivo. The purpose of present work was to optimize the design and thus enhance the efficacy of GOX-MS against multidrug resistant (MDR) cancer cells. GOX-MS with different mean diameters of 4, 20 or 140 μm were prepared using an emulsification-internal gelation-adsorption-chitosan coating method with varying compositions and conditions. The GOX loading efficiency, loading level, relative bioactivity of GOX-MS, and GOX leakage were determined and optimal chitosan concentrations in the coating solution were identified. The influence of particle size on cellular uptake, ROS generation, cytotoxicity and their underlying mechanisms was investigated. At the same GOX dose and incubation time, smaller sized GOX-MS produced larger amounts of H2O2 in cell culture medium and greater cytotoxicity toward murine breast cancer MDR (EMT6/AR1.0) and wild type (EMT6/WT) cells. Fluorescence and confocal laser scanning microscopy revealed significant uptake of small sized (4 μm) GOX-MS by both MDR and WT cells, but no cellular uptake of large (140 μm) GOX-MS. The GOX-MS were equally effective in killing both MDR cells and WT cells. The cytotoxicity of the GOX formulations was positively correlated with membrane damage and lipid peroxidation. GOX-MS induced greater membrane damage and lipid peroxidation in MDR cells than the WT cells. These results suggest that the optimized, small micron-sized GOX-MS are highly effective against MDR breast cancer cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparative molecular field analysis of fenoterol derivatives: A platform towards highly selective and effective beta(2)-adrenergic receptor agonists.

PubMed

Jozwiak, Krzysztof; Woo, Anthony Yiu-Ho; Tanga, Mary J; Toll, Lawrence; Jimenez, Lucita; Kozocas, Joseph A; Plazinska, Anita; Xiao, Rui-Ping; Wainer, Irving W

2010-01-15

To use a previously developed CoMFA model to design a series of new structures of high selectivity and efficacy towards the beta(2)-adrenergic receptor. Out of 21 computationally designed structures 6 compounds were synthesized and characterized for beta(2)-AR binding affinities, subtype selectivities and functional activities. the best compound is (R,R)-4-methoxy-1-naphthylfelnoterol with K(i)beta(2)-AR=0.28microm, K(i)beta(1)-AR/K(i)beta(2)-AR=573, EC(50cAMP)=3.9nm, EC(50cardio)=16nm. The CoMFA model appears to be an effective predictor of the cardiomocyte contractility of the studied compounds which are targeted for use in congestive heart failure. Copyright 2009 Elsevier Ltd. All rights reserved.

In Situ Potassium-Argon Geochronology Using Fluxed Fusion and a Double Spike

NASA Technical Reports Server (NTRS)

Hurowitz, Joel A.; Hecht, Michael H.; Zimmerman, Wayne F.; Neidholdt, Evan L.; Sinha, Mahadeva P.; Sturhahn, Wolfgang; Coleman, Max; McCleese, Daniel J.; Farley, Kenneth A.; Eiler, John M.;

EMG circuit design and AR analysis of EMG signs.

PubMed

Hardalaç, Firat; Canal, Rahmi

2004-12-01

In this study, electromyogram (EMG) circuit was designed and tested on 27 people. Autoregressive (AR) analysis of EMG signals recorded on the ulnar nerve region of the right hand in resting position was performed. AR method, especially in the calculation of the spectrums of stable signs, is used for frequency analysis of signs, which give frequency response as sharp peaks and valleys. In this study, as the result of AR method analysis of EMG signals frequency-time domain, frequency spectrum curves (histogram curves) were obtained. As the images belonging to these histograms were evaluated, fibrillation potential widths of the muscle fibers of the ulnar nerve region of the people (material of the study) were examined. According to the degeneration degrees of the motor nerves, nine people had myopathy, nine had neuropathy, and nine were normal.

Numerical methods for the design of gradient-index optical coatings.

PubMed

Anzengruber, Stephan W; Klann, Esther; Ramlau, Ronny; Tonova, Diana

2012-12-01

We formulate the problem of designing gradient-index optical coatings as the task of solving a system of operator equations. We use iterative numerical procedures known from the theory of inverse problems to solve it with respect to the coating refractive index profile and thickness. The mathematical derivations necessary for the application of the procedures are presented, and different numerical methods (Landweber, Newton, and Gauss-Newton methods, Tikhonov minimization with surrogate functionals) are implemented. Procedures for the transformation of the gradient coating designs into quasi-gradient ones (i.e., multilayer stacks of homogeneous layers with different refractive indices) are also developed. The design algorithms work with physically available coating materials that could be produced with the modern coating technologies.

Tuning Surface Chemistry of Polyetheretherketone by Gold Coating and Plasma Treatment

NASA Astrophysics Data System (ADS)

Novotná, Zdeňka; Rimpelová, Silvie; Juřík, Petr; Veselý, Martin; Kolská, Zdeňka; Hubáček, Tomáš; Borovec, Jakub; Švorčík, Václav

2017-06-01

Polyetheretherketone (PEEK) has good chemical and biomechanical properties that are excellent for biomedical applications. However, PEEK exhibits hydrophobic and other surface characteristics which cause limited cell adhesion. We have investigated the potential of Ar plasma treatment for the formation of a nanostructured PEEK surface in order to enhance cell adhesion. The specific aim of this study was to reveal the effect of the interface of plasma-treated and gold-coated PEEK matrices on adhesion and spreading of mouse embryonic fibroblasts. The surface characteristics (polarity, surface chemistry, and structure) before and after treatment were evaluated by various experimental techniques (gravimetry, goniometry, X-ray photoelectron spectroscopy (XPS), and electrokinetic analysis). Further, atomic force microscopy (AFM) was employed to examine PEEK surface morphology and roughness. The biological response of cells towards nanostructured PEEK was evaluated in terms of cell adhesion, spreading, and proliferation. Detailed cell morphology was evaluated by scanning electron microscopy (SEM). Compared to plasma treatment, gold coating improved PEEK wettability. The XPS method showed a decrease in the carbon concentration with increasing time of plasma treatment. Cell adhesion determined on the interface between plasma-treated and gold-coated PEEK matrices was directly proportional to the thickness of a gold layer on a sample. Our results suggest that plasma treatment in a combination with gold coating could be used in biomedical applications requiring enhanced cell adhesion.

Screen-printed (La,Sr)CrO3 coatings on ferritic stainless steel interconnects for solid oxide fuel cells using nanopowders prepared by means of ultrasonic spray pyrolysis

NASA Astrophysics Data System (ADS)

Brylewski, Tomasz; Dabek, Jaroslaw; Przybylski, Kazimierz; Morgiel, Jerzy; Rekas, Mieczyslaw

2012-06-01

In order to protect the cathode from chromium poisoning and improve electrical resistance, a perovskite (La,Sr)CrO3 coating was deposited on the surface of a DIN 50049 ferritic stainless steel by means of the screen-printing method, using a paste composed of an ultra-fine powder prepared via ultrasonic spray pyrolysis. Investigations of the oxidation process of the coated steel in air and the Ar-H2-H2O gas mixture at 1073 K for times up to 820 h showed high compactness of the protective film, good adhesion to the metal substrate, as well as area specific resistance (ASR) at a level acceptable for metallic SOFC interconnect materials. The microstructure, nanostructure, phase composition of the thick film, and in particular the film/substrate interface, were examined via chemical analyses by means of SEM-EDS and TEM-SAD. It was shown that the (La,Sr)CrO3 coating interacts with the steel during long-term thermal oxidation in the afore-mentioned conditions and intermediate, chromia-rich and/or spinel multilayer interfacial zones are formed. Cr-vaporization tests showed that the (La,Sr)CrO3 coating may play the role of barriers that decrease the volatilization rate of chromia species.

Characterization of a novel androgen receptor (AR) coregulator RIPK1 and related chemicals that suppress AR-mediated prostate cancer growth via peptide and chemical screening.

PubMed

Hsu, Cheng-Lung; Liu, Jai-Shin; Lin, Ting-Wei; Chang, Ying-Hsu; Kuo, Yung-Chia; Lin, An-Chi; Ting, Huei-Ju; Pang, See-Tong; Lee, Li-Yu; Ma, Wen-Lung; Lin, Chun-Cheng; Wu, Wen-Guey

2017-09-19

Using bicalutamide-androgen receptor (AR) DNA binding domain-ligand binding domain as bait, we observed enrichment of FxxFY motif-containing peptides. Protein database searches revealed the presence of receptor-interacting protein kinase 1 (RIPK1) harboring one FxxFY motif. RIPK1 interacted directly with AR and suppressed AR transactivation in a dose-dependent manner. Domain mapping experiments showed that the FxxFY motif in RIPK1 is critical for interactions with AR and the death domain of RIPK1 plays a crucial role in its inhibitory effect on transactivation. In terms of tissue expression, RIPK1 levels were markedly higher in benign prostate hyperplasia and non-cancerous tissue regions relative to the tumor area. With the aid of computer modeling for screening of chemicals targeting activation function 2 (AF-2) of AR, we identified oxadiazole derivatives as good candidates and subsequently generated a small library of these compounds. A number of candidates could effectively suppress AR transactivation and AR-related functions in vitro and in vivo with tolerable toxicity via inhibiting AR-peptide, AR-coregulator and AR N-C interactions. Combination of these chemicals with antiandrogen had an additive suppressive effect on AR transcriptional activity. Our collective findings may pave the way in creating new strategies for the development and design of anti-AR drugs.

Optical coating design for the annular mirrors of the Alpha I HF laser

NASA Astrophysics Data System (ADS)

Shellan, Jeffrey B.

The dielectric-coating design for the annular mirrors of the Alpha I HF laser is described along with the numerous other designs that were considered. The coatings were required to produce a 0-deg phase shift after one round trip, which involved reflections from six surfaces. Although novel high-reflectivity multilayer dielectric coatings satisfied this requirement, single-layer phase control coatings were preferred because the use of these greatly reduced coating layer-thickness control and thus resulted in significant program savings. Among the single-layer designs investigated, a coating consisting of a 0.06-micron-thick SiO layer was found to be sufficient for all surfaces except those of the rear cone, for which a 0.515-micron thick SiO layer was recommended. The metallic substrate selected was Au. These coatings were found to have a high damage threshold, provide the necessary polarization phase control, and to be quite forgiving to thickness deposition errors that were anticipated using existing chambers.

Thermal and Environmental Barrier Coatings for Advanced Propulsion Engine Systems

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Miller, Robert A.

2004-01-01

Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. For future high performance engines, the development of advanced ceramic barrier coating systems will allow these coatings to be used to simultaneously increase engine operating temperature and reduce cooling requirements, thereby leading to significant improvements in engine power density and efficiency. In order to meet future engine performance and reliability requirements, the coating systems must be designed with increased high temperature stability, lower thermal conductivity, and improved thermal stress and erosion resistance. In this paper, ceramic coating design and testing considerations will be described for high temperature and high-heat-flux engine applications in hot corrosion and oxidation, erosion, and combustion water vapor environments. Further coating performance and life improvements will be expected by utilizing advanced coating architecture design, composition optimization, and improved processing techniques, in conjunction with modeling and design tools.

Extraction of total nucleic acid based on silica-coated magnetic particles for RT-qPCR detection of plant RNA virus/viroid.

PubMed

Sun, Ning; Deng, Congliang; Zhao, Xiaoli; Zhou, Qi; Ge, Guanglu; Liu, Yi; Yan, Wenlong; Xia, Qiang

2014-02-01

In this study, a nucleic acid extraction method based on silica-coated magnetic particles (SMPs) and RT-qPCR assay was developed to detect Arabis mosaic virus (ArMV), Lily symptomless virus (LSV), Hop stunt viroid (HSVd) and grape yellow speckle viroid 1 (GYSVd-1). The amplification sequences of RT-qPCR were reversely transcribed in vitro as RNA standard templates. The standard curves covered six or seven orders of magnitude with a detection limit of 100 copies per each assay. Extraction efficiency of the SMPs method was evaluated by recovering spiked ssRNAs from plant samples and compared to two commercial kits (TRIzol and RNeasy Plant mini kit). Results showed that the recovery rate of SMPs method was comparable to the commercial kits when spiked ssRNAs were extracted from lily leaves, whereas it was two or three times higher than commercial kits when spiked ssRNAs were extracted from grapevine leaves. SMPs method was also used to extract viral nucleic acid from15 ArMV-positive lily leaf samples and 15 LSV-positive lily leaf samples. SMPs method did not show statistically significant difference from other methods on detecting ArMV, but LSV. The SMPs method has the same level of virus load as the TRIzol, and its mean virus load of was 0.5log10 lower than the RNeasy Plant mini kit. Nucleic acid was extracted from 19 grapevine-leaf samples with SMPs and the two commercial kits and subsequently screened for HSVd and GYSVd-1 by RT-qPCR. Regardless of HSVd or GYSVd-1, SMPs method outperforms other methods on both positive rate and the viroid load. In conclusion, SMPs method was able to efficiently extract the nucleic acid of RNA viruses or viroids, especially grapevine viroids, from lily-leaf or grapevine-leaf samples for RT-qPCR detection. Copyright © 2013 Elsevier B.V. All rights reserved.

Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat

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

None

BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

Computational design and experimental validation of new thermal barrier systems

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

Guo, Shengmin

2015-03-31

The focus of this project is on the development of a reliable and efficient ab initio based computational high temperature material design method which can be used to assist the Thermal Barrier Coating (TBC) bond-coat and top-coat design. Experimental evaluations on the new TBCs are conducted to confirm the new TBCs’ properties. Southern University is the subcontractor on this project with a focus on the computational simulation method development. We have performed ab initio density functional theory (DFT) method and molecular dynamics simulation on screening the top coats and bond coats for gas turbine thermal barrier coating design and validationmore » applications. For experimental validations, our focus is on the hot corrosion performance of different TBC systems. For example, for one of the top coatings studied, we examined the thermal stability of TaZr 2.75O 8 and confirmed it’s hot corrosion performance.« less

Superhydrophobic nanostructured Kapton® surfaces fabricated through Ar + O2 plasma treatment: Effects of different environments on wetting behaviour

NASA Astrophysics Data System (ADS)

Barshilia, Harish C.; Ananth, A.; Gupta, Nitant; Anandan, C.

2013-03-01

Kapton® [poly (4,4'-oxy diphenylene pyromellitimide)] polyimides have widespread usage in semiconductor devices, solar arrays, protective coatings and space applications, due to their excellent chemical and physical properties. In addition to their inherent properties, imparting superhydrophobicity on these surfaces will be an added advantage. Present work describes the usage of Ar + O2 plasma treatment for the preparation of superhydrophobic Kapton® surfaces. Immediately after the plasma treatment, the surfaces showed superhydrophilicity as a result of high energy dangling bonds and polar group concentration. But the samples kept in low vacuum for 48 h exhibited superhydrophobicity with high water contact angles (>150°). It is found that the post plasma treatment process, called ageing, especially in low vacuum plays an important role in delivering superhydrophobic property to Kapton®. Field emission scanning electron microscopy and atomic force microscopy were used to probe the physical changes in the surface of the Kapton®. The surfaces showed formation of nano-feathers and nano-tussock microstructures with variation in surface roughness against plasma treatment time. A thorough chemical investigation was performed using Fourier transform infrared spectroscopy and micro-Raman spectroscopy, which revealed changes in the surface of the Ar + O2 plasma treated Kapton®. Surface chemical species of Kapton® were confirmed again by X-ray photoelectron spectroscopy spectra for untreated surfaces whereas Ar + O2 plasma treated samples showed the de-bonding and re-organization of structural elements. Creation of surface roughness plays a dominant role in the contribution of superhydrophobicity to Kapton® apart from the surface modifications due to Ar + O2 plasma treatment and ageing in low vacuum.

Hard TiCx/SiC/a-C:H nanocomposite thin films using pulsed high energy density plasma focus device

NASA Astrophysics Data System (ADS)

Umar, Z. A.; Rawat, R. S.; Tan, K. S.; Kumar, A. K.; Ahmad, R.; Hussain, T.; Kloc, C.; Chen, Z.; Shen, L.; Zhang, Z.

2013-04-01

Thin films of TiCx/SiC/a-C:H were synthesized on Si substrates using a complex mix of high energy density plasmas and instability accelerated energetic ions of filling gas species, emanated from hot and dense pinched plasma column, in dense plasma focus device. The conventional hollow copper anode of Mather type plasma focus device was replaced by solid titanium anode for synthesis of TiCx/SiC/a-C:H nanocomposite thin films using CH4:Ar admixture of (1:9, 3:7 and 5:5) for fixed 20 focus shots as well as with different number of focus shots with fixed CH4:Ar admixture ratio 3:7. XRD results showed the formation of crystalline TiCx/SiC phases for thin film synthesized using different number of focus shots with CH4:Ar admixture ratio fixed at 3:7. SEM results showed that the synthesized thin films consist of nanoparticle agglomerates and the size of agglomerates depended on the CH4:Ar admixture ratio as well as on the number of focus shots. Raman analysis showed the formation of polycrystalline/amorphous Si, SiC and a-C for different CH4:Ar ratio as well as for different number of focus shots. The XPS analysis confirmed the formation of TiCx/SiC/a-C:H composite thin film. Nanoindentation results showed that the hardness and elastic modulus values of composite thin films increased with increasing number of focus shots. Maximum values of hardness and elastic modulus at the surface of the composite thin film were found to be about 22 and 305 GPa, respectively for 30 focus shots confirming the successful synthesis of hard composite TiCx/SiC/a-C:H coatings.

Design and Sizing of the Air Revitalization System for Altair Lunar Lander

NASA Technical Reports Server (NTRS)

Allada, Rama Kumar

2009-01-01

Designing closed-loop Air Revitalization Systems (ARS) for human spaceflight applications requires a delicate balance between designing for system robustness while minimizing system power and mass requirements. This presentation will discuss the design of the ARS for the Altair Lunar Lander. The presentation will illustrate how dynamic simulations, using Aspen Custom Modeler, were used to develop a system configuration with the ability to control atmospheric conditions under a wide variety of circumstances while minimizing system mass/volume and the impact on overall power requirements for the Lander architecture.

Studies and testing of antireflective (AR) coatings for soda-lime glass

NASA Technical Reports Server (NTRS)

Pastirik, E. M.; Sparks, T. G.; Coleman, M. G.

1978-01-01

Processes for producing antireflection films on glass are concentrated in three areas: acid etching of glass, plasma etching of glass, and acid development of sodium silicate films on glass. The best transmission was achieved through the acid etching technique, while the most durable films were produced from development of sodium silicate films. Control of the acid etching technique is presently inadequate for production implementation. While films having excellent antireflective properties were fabricated by plasma etching techniques, all were water soluble.

Polarization Decay Fit for Assured Cathodic Protection of Steel Structures: Final Report on Project F12-AR03

DTIC Science & Technology

2016-09-01

natural gas pipelines , water pipelines , and metallic USTs. The full and complete data sets for curve-fit development were not pro- vided to ERDC...Dunmire (OUSD(AT&L)), Bernie Rodriguez (IMPW-E), and Valerie D. Hines (DAIM-ODF). The work was performed by the Materials and Structures Branch...of structures being tested increases, as in the case of pipelines that run many miles or the case of when a structure’s coating quality

Needs Assessment to Define the Training Requirements for a Basic Skills Education Program (BSEP) Curriculum Development. Revision.

DTIC Science & Technology

1984-04-01

compounds time, understanding and coordination problems. Just too many people in the process. In fact, there are numerous versions of a task with the...sometimes -his caused interruptions. Nhis was further compounded by the fact that the cnalyss * voas toarted ar-d +hen t~opped, when the first cnaiyst...productive. Discrepancies - The major discrepancy was ’he use of Anti-Seize Compound . It is applied to components as a light, thin coat to prevent i..re, any

Learning by Design: Bringing Poster Carousels to Life through Augmented Reality in a Blended English Course

ERIC Educational Resources Information Center

Alizadeh, Mehrasa; Mehran, Parisa; Koguchi, Ichiro; Takemura, Haruo

2017-01-01

In recent years, there has been a burgeoning interest in Augmented Reality (AR) technologies, especially in educational settings to edutain (i.e. educate and entertain) students and engage them in their learning. This study reports the results of the use of an AR application called BlippAR to augment poster carousel tasks in a blended English…

Androgen Receptor Variant AR-V9 Is Coexpressed with AR-V7 in Prostate Cancer Metastases and Predicts Abiraterone Resistance.

PubMed

Kohli, Manish; Ho, Yeung; Hillman, David W; Van Etten, Jamie L; Henzler, Christine; Yang, Rendong; Sperger, Jamie M; Li, Yingming; Tseng, Elizabeth; Hon, Ting; Clark, Tyson; Tan, Winston; Carlson, Rachel E; Wang, Liguo; Sicotte, Hugues; Thai, Ho; Jimenez, Rafael; Huang, Haojie; Vedell, Peter T; Eckloff, Bruce W; Quevedo, Jorge F; Pitot, Henry C; Costello, Brian A; Jen, Jin; Wieben, Eric D; Silverstein, Kevin A T; Lang, Joshua M; Wang, Liewei; Dehm, Scott M

2017-08-15

Purpose: Androgen receptor (AR) variant AR-V7 is a ligand-independent transcription factor that promotes prostate cancer resistance to AR-targeted therapies. Accordingly, efforts are under way to develop strategies for monitoring and inhibiting AR-V7 in castration-resistant prostate cancer (CRPC). The purpose of this study was to understand whether other AR variants may be coexpressed with AR-V7 and promote resistance to AR-targeted therapies. Experimental Design: We utilized complementary short- and long-read sequencing of intact AR mRNA isoforms to characterize AR expression in CRPC models. Coexpression of AR-V7 and AR-V9 mRNA in CRPC metastases and circulating tumor cells was assessed by RNA-seq and RT-PCR, respectively. Expression of AR-V9 protein in CRPC models was evaluated with polyclonal antisera. Multivariate analysis was performed to test whether AR variant mRNA expression in metastatic tissues was associated with a 12-week progression-free survival endpoint in a prospective clinical trial of 78 CRPC-stage patients initiating therapy with the androgen synthesis inhibitor, abiraterone acetate. Results: AR-V9 was frequently coexpressed with AR-V7. Both AR variant species were found to share a common 3' terminal cryptic exon, which rendered AR-V9 susceptible to experimental manipulations that were previously thought to target AR-V7 uniquely. AR-V9 promoted ligand-independent growth of prostate cancer cells. High AR-V9 mRNA expression in CRPC metastases was predictive of primary resistance to abiraterone acetate (HR = 4.0; 95% confidence interval, 1.31-12.2; P = 0.02). Conclusions: AR-V9 may be an important component of therapeutic resistance in CRPC. Clin Cancer Res; 23(16); 4704-15. ©2017 AACR . ©2017 American Association for Cancer Research.

Computing and Applying Atomic Regulons to Understand Gene Expression and Regulation

DOE PAGES

Faria, José P.; Davis, James J.; Edirisinghe, Janaka N.; ...

2016-11-24

Understanding gene function and regulation is essential for the interpretation, prediction, and ultimate design of cell responses to changes in the environment. A multitude of technologies, abstractions, and interpretive frameworks have emerged to answer the challenges presented by genome function and regulatory network inference. Here, we propose a new approach for producing biologically meaningful clusters of coexpressed genes, called Atomic Regulons (ARs), based on expression data, gene context, and functional relationships. We demonstrate this new approach by computing ARs for Escherichia coli, which we compare with the coexpressed gene clusters predicted by two prevalent existing methods: hierarchical clustering and k-meansmore » clustering. We test the consistency of ARs predicted by all methods against expected interactions predicted by the Context Likelihood of Relatedness (CLR) mutual information based method, finding that the ARs produced by our approach show better agreement with CLR interactions. We then apply our method to compute ARs for four other genomes: Shewanella oneidensis, Pseudomonas aeruginosa, Thermus thermophilus, and Staphylococcus aureus. We compare the AR clusters from all genomes to study the similarity of coexpression among a phylogenetically diverse set of species, identifying subsystems that show remarkable similarity over wide phylogenetic distances. We also study the sensitivity of our method for computing ARs to the expression data used in the computation, showing that our new approach requires less data than competing approaches to converge to a near final configuration of ARs. We go on to use our sensitivity analysis to identify the specific experiments that lead most rapidly to the final set of ARs for E. coli. As a result, this analysis produces insights into improving the design of gene expression experiments.« less

Computing and Applying Atomic Regulons to Understand Gene Expression and Regulation

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

Faria, José P.; Davis, James J.; Edirisinghe, Janaka N.

Understanding gene function and regulation is essential for the interpretation, prediction, and ultimate design of cell responses to changes in the environment. A multitude of technologies, abstractions, and interpretive frameworks have emerged to answer the challenges presented by genome function and regulatory network inference. Here, we propose a new approach for producing biologically meaningful clusters of coexpressed genes, called Atomic Regulons (ARs), based on expression data, gene context, and functional relationships. We demonstrate this new approach by computing ARs for Escherichia coli, which we compare with the coexpressed gene clusters predicted by two prevalent existing methods: hierarchical clustering and k-meansmore » clustering. We test the consistency of ARs predicted by all methods against expected interactions predicted by the Context Likelihood of Relatedness (CLR) mutual information based method, finding that the ARs produced by our approach show better agreement with CLR interactions. We then apply our method to compute ARs for four other genomes: Shewanella oneidensis, Pseudomonas aeruginosa, Thermus thermophilus, and Staphylococcus aureus. We compare the AR clusters from all genomes to study the similarity of coexpression among a phylogenetically diverse set of species, identifying subsystems that show remarkable similarity over wide phylogenetic distances. We also study the sensitivity of our method for computing ARs to the expression data used in the computation, showing that our new approach requires less data than competing approaches to converge to a near final configuration of ARs. We go on to use our sensitivity analysis to identify the specific experiments that lead most rapidly to the final set of ARs for E. coli. As a result, this analysis produces insights into improving the design of gene expression experiments.« less

Effectiveness of an audience response system on orthodontic knowledge retention of undergraduate dental students – a randomised control trial

PubMed Central

Robson, Nicholas; Popat, Hashmat; Richmond, Stephen; Farnell, Damian J. J.

2015-01-01

Objective:: To determine the effect of an audience response system (ARS) on knowledge retention of dental students and to gauge student perceptions of using the ARS. Design:: Randomised control study. Setting:: School of Dentistry, Cardiff University. Participants:: Seventy four second-year dental students were stratified by gender and randomised anonymously to one of two groups. Methods:: One group received a lecture on orthodontic terminology and diagnosis in a traditional didactic format and the other received the same lecture integrated with ARS slides. Students completed an assessment of multiple-choice questions (MCQs) scored out of 20, before and immediately after the lecture. Students were also asked to complete a self-reported questionnaire on their perceptions of ARS. Results:: Both groups had statistically significant increases in MCQ scores post-lecture (ARS mean increase 3.6 SD2.0, 95% CI 2.2–3.5 and Didactic mean increase 2.9 SD2.3, 95% CI 2.8–4.3). A mixed-design analysis of variance showed that ARS led to an improved MCQ score (by 0.8 or 25%) compared to the didactic group, although this effect was not significant (P = 0.15). The effect of gender at baseline (P = 0.49), post-lecture (P = 0.73) and increase in MCQ score split by group (P = 0.46) was also not significant. Students reported that the ARS was easy to use, helped them engage with the lecture and encouraged them to work harder. Conclusion:: The ARS did not lead to a significant increase in short-term orthodontic knowledge recall of students compared with didactic teaching. However, the use of ARS within orthodontic teaching could make lectures more interactive and engaging. PMID:26282015

Low Conductivity Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming

2005-01-01

Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future engine higher fuel efficiency and lower emission goals. In this presentation, thermal barrier coating development considerations and requirements will be discussed. An experimental approach is established to monitor in real time the thermal conductivity of the coating systems subjected to high-heat-flux, steady-state and cyclic temperature gradients. Advanced low conductivity thermal barrier coatings have also been developed using a multi-component defect clustering approach, and shown to have improved thermal stability. The durability and erosion resistance of low conductivity thermal barrier coatings have been improved utilizing advanced coating architecture design, composition optimization, in conjunction with more sophisticated modeling and design tools.

Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon

PubMed Central

Behzad, Kasra; Mat Yunus, Wan Mahmood; Talib, Zainal Abidin; Zakaria, Azmi; Bahrami, Afarin

2012-01-01

Porous silicon (PSi) layers were formed on a p-type Si wafer. Six samples were anodised electrically with a 30 mA/cm2 fixed current density for different etching times. The samples were coated with a 50–60 nm gold layer and annealed at different temperatures under Ar flow. The morphology of the layers, before and after annealing, formed by this method was investigated by scanning electron microscopy (SEM). Photoacoustic spectroscopy (PAS) measurements were carried out to measure the thermal diffusivity (TD) of the PSi and Au/PSi samples. For the Au/PSi samples, the thermal diffusivity was measured before and after annealing to study the effect of annealing. Also to study the aging effect, a comparison was made between freshly annealed samples and samples 30 days after annealing. PMID:28817037

Stable CW Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

NASA Technical Reports Server (NTRS)

Duerksen, Gary L.; Krainak, Michael A.

1999-01-01

Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by two methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback. We coupled a nominal 935 run-wavelength Fabry-Perot laser diode to an ultra narrow band (18 pm) FBG. When tuned by varying its temperature, the laser wavelength is pulled toward the centerline of the Bragg grating, and the spectrum of the laser output is seen to fall into three discrete stability regimes as measured by the side-mode suppression ratio.

Evaluating the process parameters of the dry coating process using a 2(5-1) factorial design.

PubMed

Kablitz, Caroline Désirée; Urbanetz, Nora Anne

2013-02-01

A recent development of coating technology is dry coating, where polymer powder and liquid plasticizer are layered on the cores without using organic solvents or water. Several studies evaluating the process were introduced in literature, however, little information about the critical process parameters (CPPs) is given. Aim of the study was the investigation and optimization of CPPs with respect to one of the critical quality attributes (CQAs), the coating efficiency of the dry coating process in a rotary fluid bed. Theophylline pellets were coated with hydroxypropyl methylcellulose acetate succinate as enteric film former and triethyl citrate and acetylated monoglyceride as plasticizer. A 2(5-1) design of experiments (DOEs) was created investigating five independent process parameters namely coating temperature, curing temperature, feeding/spraying rate, air flow and rotor speed. The results were evaluated by multilinear regression using the software Modde(®) 7. It is shown, that generally, low feeding/spraying rates and low rotor speeds increase coating efficiency. High coating temperatures enhance coating efficiency, whereas medium curing temperatures have been found to be optimum in terms of coating efficiency. This study provides a scientific base for the design of efficient dry coating processes with respect to coating efficiency.

Design and synthesis of aryloxypropanolamine as β3-adrenergic receptor antagonist in cancer and lipolysis.

PubMed

Jin, Jiyu; Miao, Chunxiao; Wang, Zhilong; Zhang, Wanli; Zhang, Xiongwen; Xie, Xin; Lu, Wei

2018-04-25

β-adrenergic receptors (β-ARs) are broadly distributed in various tissues and regulate a panel of important physiological functions and disease states including cancer. Above all, β 3 -adrenergic receptor (β 3 -AR) plays a significant role in regulating lipolysis and thermogenesis in adipose tissue. In this study, we designed and synthesized a series of novel L-748,337 derivatives as selective human β 3 -AR antagonists. Among all the tested L-748,337 analogs, compound 23d was found to display 23-fold more potent β 3 -AR antagonist activity (EC 50  = 0.5117 nM) than L-748,337 (EC 50  = 11.91 nM). In vivo, compound 23d could alleviate weight loss and inhibit tumor growth in C26 tumor cachexia animal model. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Fabrication of Cu2ZnSn(S,Se)4 (CZTSSe) absorber films based on solid-phase synthesis and blade coating processes

NASA Astrophysics Data System (ADS)

Ma, Ruixin; Yang, Fan; Li, Shina; Zhang, Xiaoyong; Li, Xiang; Cheng, Shiyao; Liu, Zilin

2016-04-01

CZTSSe is an important earth abundant collection of materials for the development of low cost and high efficiency thin film solar cells. This work developed a simple non-vacuum-based route to fabricate CZTSSe absorber films. This was demonstrated by first synthesizing Cu2ZnSnS4 (CZTS) nano-crystalline based on solid-phase synthesis. Then a stable colloidal ink composed of CZTS nano-crystalline was blade coated on Mo-coated substrates followed by an annealing process under Ar atmosphere. After CZTS films formation, the films were sintered into CZTSSe absorber films by exposing them under Selenium vapor. The formation of a kesterite type CZTS was confirmed using X-ray diffraction and Raman scattering measurements. The band gap of CZTSSe absorber films was determined to be 1.26 eV, which was appropriate for use as an absorber layer in thin film solar cells. The CZTSSe absorber films showed a good photovoltatic performance, demonstrating this simple approach had great potential for CZTSSe solar cell production.

Novel approaches for targeting the adenosine A2A receptor.

PubMed

Yuan, Gengyang; Gedeon, Nicholas G; Jankins, Tanner C; Jones, Graham B

2015-01-01

The adenosine A2A receptor (A2AR) represents a drug target for a wide spectrum of diseases. Approaches for targeting this membrane-bound protein have been greatly advanced by new stabilization techniques. The resulting X-ray crystal structures and subsequent analyses provide deep insight to the A2AR from both static and dynamic perspectives. Application of this, along with other biophysical methods combined with fragment-based drug design (FBDD), has become a standard approach in targeting A2AR. Complementarities of in silico screening based- and biophysical screening assisted- FBDD are likely to feature in future approaches in identifying novel ligands against this key receptor. This review describes evolution of the above approaches for targeting A2AR and highlights key modulators identified. It includes a review of: adenosine receptor structures, homology modeling, X-ray structural analysis, rational drug design, biophysical methods, FBDD and in silico screening. As a drug target, the A2AR is attractive as its function plays a role in a wide spectrum of diseases including oncologic, inflammatory, Parkinson's and cardiovascular diseases. Although traditional approaches such as high-throughput screening and homology model-based virtual screening (VS) have played a role in targeting A2AR, numerous shortcomings have generally restricted their applications to specific ligand families. Using stabilization methods for crystallization, X-ray structures of A2AR have greatly accelerated drug discovery and influenced development of biophysical-in silico hybrid screening methods. Application of these new methods to other ARs and G-protein-coupled receptors is anticipated in the future.

Discovery Proteomics Identifies a Molecular Link between the Coatomer Protein Complex I and Androgen Receptor-dependent Transcription*

PubMed Central

Hsiao, Jordy J.; Smits, Melinda M.; Ng, Brandon H.; Lee, Jinhee; Wright, Michael E.

2016-01-01

Aberrant androgen receptor (AR)-dependent transcription is a hallmark of human prostate cancers. At the molecular level, ligand-mediated AR activation is coordinated through spatial and temporal protein-protein interactions involving AR-interacting proteins, which we designate the “AR-interactome.” Despite many years of research, the ligand-sensitive protein complexes involved in ligand-mediated AR activation in prostate tumor cells have not been clearly defined. Here, we describe the development, characterization, and utilization of a novel human LNCaP prostate tumor cell line, N-AR, which stably expresses wild-type AR tagged at its N terminus with the streptavidin-binding peptide epitope (streptavidin-binding peptide-tagged wild-type androgen receptor; SBP-AR). A bioanalytical workflow involving streptavidin chromatography and label-free quantitative mass spectrometry was used to identify SBP-AR and associated ligand-sensitive cytosolic proteins/protein complexes linked to AR activation in prostate tumor cells. Functional studies verified that ligand-sensitive proteins identified in the proteomic screen encoded modulators of AR-mediated transcription, suggesting that these novel proteins were putative SBP-AR-interacting proteins in N-AR cells. This was supported by biochemical associations between recombinant SBP-AR and the ligand-sensitive coatomer protein complex I (COPI) retrograde trafficking complex in vitro. Extensive biochemical and molecular experiments showed that the COPI retrograde complex regulates ligand-mediated AR transcriptional activation, which correlated with the mobilization of the Golgi-localized ARA160 coactivator to the nuclear compartment of prostate tumor cells. Collectively, this study provides a bioanalytical strategy to validate the AR-interactome and define novel AR-interacting proteins involved in ligand-mediated AR activation in prostate tumor cells. Moreover, we describe a cellular system to study how compartment-specific AR-interacting proteins influence AR activation and contribute to aberrant AR-dependent transcription that underlies the majority of human prostate cancers. PMID:27365400

The Application of Augmented Reality in Online Education: A Review of Studies Published in Selected Journals from 2003 to 2012

ERIC Educational Resources Information Center

Tsai, Chia-Wen; Shen, Pei-Di; Fan, Ya-Ting

2014-01-01

In this paper, the authors reviewed the empirical augmented reality (AR) and online education studies, and those focused on designing or development of AR to help students learn, published in SSCI, SCI-EXPANDED, and A&HCI journals from 2003 to 2012. The authors in this study found that the number of AR and online education studies has…

Surface Properties and Catalytic Performance of Activated Carbon Fibers Supported TiO2 Photocatalyst

NASA Astrophysics Data System (ADS)

Yang, Huifen; Fu, Pingfeng

Activated carbon fibers supported TiO2 photocatalyst (TiO2/ACF) in felt-form was successfully prepared with a dip-coating process using organic silicon modified acrylate copolymer as a binder followed by calcination at 500°C in a stream of Ar gas. The photocatalyst was characterized by SEM, XRD, XPS, FTIR, and BET surface area. Most of carbon fibers were coated with uniformly distributed TiO2 clusters of nearly 100 nm. The loaded TiO2 layer was particulate for the organic binder in the compact film was carbonized. According to XPS and FTIR analysis, amorphous silica in carbon grains was synthesized after carbonizing organic silicon groups, and the Ti-O-Si bond was formed between the interface of loaded TiO2 and silica. Additionally, the space between adjacent carbon fibers still remained unfilled after TiO2 coating, into which both UV light and polluted solutions could penetrate to form a three-dimensional environment for photocatalytic reactions. While loaded TiO2 amount increased to 456 mg TiO2/1 g ACF, the TiO2/ACF catalyst showed its highest photocatalytic activity, and this activity only dropped about 10% after 12 successive runs, exhibiting its high fixing stability of coated TiO2.

Splicing Factor Prp8 Interacts With NES(AR) and Regulates Androgen Receptor in Prostate Cancer Cells.

PubMed

Wang, Dan; Nguyen, Minh M; Masoodi, Khalid Z; Singh, Prabhpreet; Jing, Yifeng; O'Malley, Katherine; Dar, Javid A; Dhir, Rajiv; Wang, Zhou

2015-12-01

Androgen receptor (AR) plays a pivotal role in the development of primary as well as advanced castration-resistant prostate cancer. Previous work in our lab identified a novel nuclear export signal (NES) (NES(AR)) in AR ligand-binding domain essential for AR nucleocytoplasmic trafficking. By characterizing the localization of green fluorescence protein (GFP)-tagged NES(AR), we designed and executed a yeast mutagenesis screen and isolated 7 yeast mutants that failed to display the NES(AR) export function. One of those mutants was identified as the splicing factor pre-mRNA processing factor 8 (Prp8). We further showed that Prp8 could regulate NES(AR) function using short hairpin RNA knockdown of Prp8 coupled with a rapamycin export assay in mammalian cells and knockdown of Prp8 could induce nuclear accumulation of GFP-tagged AR in PC3 cells. Prp8 expression was decreased in castration-resistant LuCaP35 xenograft tumors as compared with androgen-sensitive xenografts. Laser capture microdissection and quantitative PCR showed Prp8 mRNA levels were decreased in human prostate cancer specimens with high Gleason scores. In prostate cancer cells, coimmunoprecipitation and deletion mutagenesis revealed a physical interaction between Prp8 and AR mainly mediated by NES(AR). Luciferase assay with prostate specific antigen promoter-driven reporter demonstrated that Prp8 regulated AR transcription activity in prostate cancer cells. Interestingly, Prp8 knockdown also increased polyubiquitination of endogenous AR. This may be 1 possible mechanism by which it modulates AR activity. These results show that Prp8 is a novel AR cofactor that interacts with NES(AR) and regulates AR function in prostate cancer cells.

Architectural design of diamond-like carbon coatings for long-lasting joint replacements.

PubMed

Liu, Yujing; Zhao, Xiaoli; Zhang, Lai-Chang; Habibi, Daryoush; Xie, Zonghan

2013-07-01

Surface engineering through the application of super-hard, low-friction coatings as a potential approach for increasing the durability of metal-on-metal replacements is attracting significant attention. In this study innovative design strategies are proposed for the development of diamond-like-carbon (DLC) coatings against the damage caused by wear particles on the joint replacements. Finite element modeling is used to analyze stress distributions induced by wear particles of different sizes in the newly-designed coating in comparison to its conventional monolithic counterpart. The critical roles of architectural design in regulating stress concentrations and suppressing crack initiation within the coatings is elucidated. Notably, the introduction of multilayer structure with graded modulus is effective in modifying the stress field and reducing the magnitude and size of stress concentrations in the DLC diamond-like-carbon coatings. The new design is expected to greatly improve the load-carrying ability of surface coatings on prosthetic implants, in addition to the provision of damage tolerance through crack arrest. Copyright © 2013 Elsevier B.V. All rights reserved.

Implementation of quality by design approach in manufacturing process optimization of dry granulated, immediate release, coated tablets - a case study.

PubMed

Teżyk, Michał; Jakubowska, Emilia; Milanowski, Bartłomiej; Lulek, Janina

2017-10-01

The aim of this study was to optimize the process of tablets compression and identification of film-coating critical process parameters (CPPs) affecting critical quality attributes (CQAs) using quality by design (QbD) approach. Design of experiment (DOE) and regression methods were employed to investigate hardness, disintegration time, and thickness of uncoated tablets depending on slugging and tableting compression force (CPPs). Plackett-Burman experimental design was applied to identify critical coating process parameters among selected ones that is: drying and preheating time, atomization air pressure, spray rate, air volume, inlet air temperature, and drum pressure that may influence the hardness and disintegration time of coated tablets. As a result of the research, design space was established to facilitate an in-depth understanding of existing relationship between CPPs and CQAs of intermediate product (uncoated tablets). Screening revealed that spray rate and inlet air temperature are two most important factors that affect the hardness of coated tablets. Simultaneously, none of the tested coating factors have influence on disintegration time. The observation was confirmed by conducting film coating of pilot size batches.

Characterization of the cod (Gadus morhua) steroidogenic acute regulatory protein (StAR) sheds light on StAR gene structure in fish.

PubMed

Goetz, Frederick W; Norberg, Birgitta; McCauley, Linda A R; Iliev, Dimitar B

2004-03-01

The full-length cDNA for the cod (Gadus morhua) StAR was cloned by RT-PCR and library screening using ovarian RNA. From the library screening, 2 size classes of cDNA were obtained; a 1577 bp cDNA (cStAR1) and a 2851 bp cDNA (cStAR2). The cStAR1 cDNA presumably encodes a protein of 286 amino acids. The cStAR2 cDNA was composed of 6 separated sequences that contained all of the coding regions of cStAR1 when added together, but also contained 5 noncoding regions not observed in cStAR1. Polymerase chain reactions of cod genomic DNA produced products slightly larger than cStAR2. The sequence of these products were the same as cStAR2 but revealed one additional noncoding region (intron). Thus, the fish StAR gene contains the same number of exons (7) and introns (6) as observed in mammals, but is approximately half the size of the mammalian gene. Using Northern analysis and RT-PCR, cStAR1 expression was observed only in testes, ovaries and head kidneys. Polymerase chain reaction products were also observed using cDNA from steroidogenic tissues and primers designed to regions specific for cStAR2, indicating that cStAR2 is expressed in tissues and may account for the presence of larger transcripts observed on Northern blots.

Optical design of space cameras for automated rendezvous and docking systems

NASA Astrophysics Data System (ADS)

Zhu, X.

2018-05-01

Visible cameras are essential components of a space automated rendezvous and docking (AR and D) system, which is utilized in many space missions including crewed or robotic spaceship docking, on-orbit satellite servicing, autonomous landing and hazard avoidance. Cameras are ubiquitous devices in modern time with countless lens designs that focus on high resolution and color rendition. In comparison, space AR and D cameras, while are not required to have extreme high resolution and color rendition, impose some unique requirements on lenses. Fixed lenses with no moving parts and separated lenses for narrow and wide field-of-view (FOV) are normally used in order to meet high reliability requirement. Cemented lens elements are usually avoided due to wide temperature swing and outgassing requirement in space environment. The lenses should be designed with exceptional straylight performance and minimum lens flare given intense sun light and lacking of atmosphere scattering in space. Furthermore radiation resistant glasses should be considered to prevent glass darkening from space radiation. Neptec has designed and built a narrow FOV (NFOV) lens and a wide FOV (WFOV) lens for an AR and D visible camera system. The lenses are designed by using ZEMAX program; the straylight performance and the lens baffles are simulated by using TracePro program. This paper discusses general requirements for space AR and D camera lenses and the specific measures for lenses to meet the space environmental requirements.

Characterization of high power impulse magnetron sputtering discharges

NASA Astrophysics Data System (ADS)

Hala, Matej

Paper I: In the first paper, we present a new approach in the characterization of the high power pulsed magnetron sputtering (HiPIMS) discharge evolution—time- and species-resolved plasma imaging—employing a set of band-pass optical interference filters suitable for the isolation of the emission originating from different species populating the plasma. We demonstrate that the introduction of such filters can be used to distinguish different phases of the discharge, and to visualize numerous plasma effects including background gas excitations during the discharge ignition, gas shock waves, and expansion of metal-rich plasmas. In particular, the application of this technique is shown on the diagnostics of the 200 µs long non-reactive HiPIMS discharges using a Cr target. Paper II: In order to gain further information about the dynamics of reactive HiPIMS discharges, both fast plasma imaging and time- and space-resolved optical emission spectroscopy (OES) are used for a systematic investigation of the 200 µs long HiPIMS pulses operated in Ar, N2 and N 2/Ar mixtures and at various pressures. It is observed that the dense metal plasma created next to the target propagates in the reactor at a speed ranging from 0.7 to 3.5 km s-1, depending on the working gas composition and the pressure. In fact, it increases with higher N 2 concentration and with lower pressure. The visible form of the propagating plasma wave changes from a hemispherical shape in Ar to a drop-like shape extending far from the target with increasing N2 concentration, owing to the significant emission from molecular N2. Interestingly, the evidence of the target self-sputtering is found for all investigated conditions, including pure N2 atmosphere. Paper III: Here, we report on the time- and species-resolved plasma imaging analysis of the dynamics of the 200 µs long HiPIMS discharges above a Cr target ignited in pure O2. It is shown that the discharge emission is dominated solely by neutral and ionized oxygen, since the monitored discharge is operated above a fully poisoned (oxidized) target from which only a minimum of Cr is sputtered. No signs of self-sputtering have been detected, in contrast to the discharges in Ar, N2 and N2/Ar mixtures previously investigated. Paper IV: In the fourth paper, we study different power management approaches in HiPIMS and MPPMS and their effects on the pulsed discharge evolution, plasma composition, and metal ionization estimated by OES. It is shown that HiPIMS is the only technique that enables the discharge operation in self-sputtering mode within the investigated range of applied powers, resulting in a significantly higher ionization of the sputtered metal than that reached with MPPMS. In contrast to HiPIMS, MPPMS provides a higher versatility in adjusting the pulse shape and pulse length. This feature can be particularly beneficial, for instance, in the discharge ignition. Nb coatings prepared by HiPIMS and MPPMS have very similar deposition rates that are lower than in DCMS. All films prepared at p = 1Pa possess a dense columnar structure. Coatings deposited by the two high power pulsed discharges exhibit higher compressive stress and larger out-of-plane lattice spacing than those prepared by DC sputtering under comparable conditions. At higher pressure, p = 2Pa, DCMS-grown films show a tensile stress due to a porous microstructure, while films prepared by HiPIMS and MPPMS are dense and in compression, most probably due to the substantial ion bombardment. Paper V: In the last paper, we analyze the behavior of the HiPIMS, MPPMS and DCMS discharges in reactive O2/Ar gas mixtures and evaluate the characteristics of the fabricated NbOx films. We demonstrate that the surface metal oxides can be effectively sputter-eroded from the target during both HiPIMS and MPPMS pulses, and that sputtering from a partially oxide-free target is possible even at high oxygen concentrations. This results in a hysteresisfree deposition process which allows one to prepare optically transparent b2O5 coatings at a high growth rate without the need of feedback control commonly used in reactive DCMS. Nb2O 5 coatings prepared by both reactive high power pulsed discharges exhibited a high index of refraction, a low extinction coefficient, a near-zero internal stress, and high hardness and Young's modulus. The HiPIMS-deposited coatings showed the highest deposition rate and the highest index of refraction. The latter observation was related to the higher film density. In comparison, MPPMS exhibited the highest power-normalized deposition rate among the three investigated deposition techniques, possibly due to the longer period that is available for the gradual target cleaning. (Abstract shortened by UMI.).

Optimization of process parameters for a quasi-continuous tablet coating system using design of experiments.

PubMed

Cahyadi, Christine; Heng, Paul Wan Sia; Chan, Lai Wah

2011-03-01

The aim of this study was to identify and optimize the critical process parameters of the newly developed Supercell quasi-continuous coater for optimal tablet coat quality. Design of experiments, aided by multivariate analysis techniques, was used to quantify the effects of various coating process conditions and their interactions on the quality of film-coated tablets. The process parameters varied included batch size, inlet temperature, atomizing pressure, plenum pressure, spray rate and coating level. An initial screening stage was carried out using a 2(6-1(IV)) fractional factorial design. Following these preliminary experiments, optimization study was carried out using the Box-Behnken design. Main response variables measured included drug-loading efficiency, coat thickness variation, and the extent of tablet damage. Apparent optimum conditions were determined by using response surface plots. The process parameters exerted various effects on the different response variables. Hence, trade-offs between individual optima were necessary to obtain the best compromised set of conditions. The adequacy of the optimized process conditions in meeting the combined goals for all responses was indicated by the composite desirability value. By using response surface methodology and optimization, coating conditions which produced coated tablets of high drug-loading efficiency, low incidences of tablet damage and low coat thickness variation were defined. Optimal conditions were found to vary over a large spectrum when different responses were considered. Changes in processing parameters across the design space did not result in drastic changes to coat quality, thereby demonstrating robustness in the Supercell coating process. © 2010 American Association of Pharmaceutical Scientists

Everyone's answering: using technology to increase classroom participation.

PubMed

Filer, Debra

2010-01-01

A study was designed to assess the impact of a wireless technology known as an audience response system (ARS), commonly known clickers, on learning and student engagement in a nursing classroom. Students in the control group responded verbally to questions posed during lectures, while students in the intervention groups responded anonymously using the ARS. Although no significant improvement in postlecture quizzes was noted, students in ARS-enhanced lectures reported significantly higher satisfaction scores. The use of ARS promoted a sense of comfort, encouraged participation, and motivated students to answer questions and interact with the subject matter.

Beam-induced back-streaming electron suppression analysis for an accelerator type neutron generator designed for 40Ar/39Ar geochronology.

PubMed

Waltz, Cory; Ayllon, Mauricio; Becker, Tim; Bernstein, Lee; Leung, Ka-Ngo; Kirsch, Leo; Renne, Paul; Bibber, Karl Van

2017-07-01

A facility based on a next-generation, high-flux D-D neutron generator has been commissioned and it is now operational at the University of California, Berkeley. The current generator designed for 40 Ar/ 39 Ar dating of geological materials produces nearly monoenergetic 2.45MeV neutrons at outputs of 10 8 n/s. The narrow energy range is advantageous relative to the 235 U fission spectrum neutrons due to (i) reduced 39 Ar recoil energy, (ii) minimized production of interfering argon isotopes from K, Ca, and Cl, and (iii) reduced total activity for radiological safety and waste generation. Calculations provided show that future conditioning at higher currents and voltages will allow for a neutron output of over 10 10 n/s, which is a necessary requirement for production of measurable quantities of 39 Ar through the reaction 39 K(n,p) 39 Ar. A significant problem encountered with increasing deuteron current was beam-induced electron backstreaming. Two methods of suppressing secondary electrons resulting from the deuterium beam striking the target were tested: the application of static electric and magnetic fields. Computational simulations of both techniques were done using a finite element analysis in COMSOL Multiphysics ® . Experimental tests verified these simulations. The most reliable suppression was achieved via the implementation of an electrostatic shroud with a voltage offset of -800V relative to the target. Copyright © 2017. Published by Elsevier Ltd.

Implementation of augmented reality in operative dentistry learning.

PubMed

Llena, C; Folguera, S; Forner, L; Rodríguez-Lozano, F J

2018-02-01

To evaluate the efficacy of augmented reality (AR) in the gaining of knowledge and skills amongst dental students in the design of cavity preparations and analyse their degree of satisfaction. AR cavity models were prepared for use with computers and mobile devices. Forty-one students were divided into two groups (traditional teaching methods vs AR). Questionnaires were designed to evaluate knowledge and skills, with the administration of a satisfaction questionnaire for those using AR. The degree of compliance with the standards in cavity design was assessed. The Mann-Whitney U-test was used to compare knowledge and skills between the two groups, and the Wilcoxon test was applied to compare intragroup differences. The chi-square test in turn was used to compare the qualitative parameters of the cavity designs between the groups. Statistical significance was considered for P<.05 in all cases. No significant differences were observed in level of knowledge before, immediately after or 6 months after teaching between the two groups (P>.05). Although the results corresponding to most of the studied skills parameters were better in the experimental group, significant differences (P<.05) were only founded for cavity depth and extent for Class I and divergence of the buccal and lingual walls for the Class II. The experience was rated as favourable or very favourable by 100% of the participants. The students showed preference for computers (60%) vs mobile devices (10%). The AR techniques favoured the gaining of knowledge and skills and were regarded as a useful tool by the students. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Ground Testbed to Advance US Capability in Autonomous Rendezvous and Docking Project

NASA Technical Reports Server (NTRS)

D'Souza, Chris

2014-01-01

This project will advance the Autonomous Rendezvous and Docking (AR&D) GNC system by testing it on hardware, particularly in a flight processor, with a goal of testing it in IPAS with the Waypoint L2 AR&D scenario. The entire Agency supports development of a Commodity for Autonomous Rendezvous and Docking (CARD) as outlined in the Agency-wide Community of Practice whitepaper entitled: "A Strategy for the U.S. to Develop and Maintain a Mainstream Capability for Automated/Autonomous Rendezvous and Docking in Low Earth Orbit and Beyond". The whitepaper establishes that 1) the US is in a continual state of AR&D point-designs and therefore there is no US "off-the-shelf" AR&D capability in existence today, 2) the US has fallen behind our foreign counterparts particularly in the autonomy of AR&D systems, 3) development of an AR&D commodity is a national need that would benefit NASA, our commercial partners, and DoD, and 4) an initial estimate indicates that the development of a standardized AR&D capability could save the US approximately $60M for each AR&D project and cut each project's AR&D flight system implementation time in half.

Overcoming mutation-based resistance to antiandrogens with rational drug design

PubMed Central

Balbas, Minna D; Evans, Michael J; Hosfield, David J; Wongvipat, John; Arora, Vivek K; Watson, Philip A; Chen, Yu; Greene, Geoffrey L; Shen, Yang; Sawyers, Charles L

2013-01-01

The second-generation antiandrogen enzalutamide was recently approved for patients with castration-resistant prostate cancer. Despite its success, the duration of response is often limited. For previous antiandrogens, one mechanism of resistance is mutation of the androgen receptor (AR). To prospectively identify AR mutations that might confer resistance to enzalutamide, we performed a reporter-based mutagenesis screen and identified a novel mutation, F876L, which converted enzalutamide into an AR agonist. Ectopic expression of AR F876L rescued the growth inhibition of enzalutamide treatment. Molecular dynamics simulations performed on antiandrogen–AR complexes suggested a mechanism by which the F876L substitution alleviates antagonism through repositioning of the coactivator recruiting helix 12. This model then provided the rationale for a focused chemical screen which, based on existing antiandrogen scaffolds, identified three novel compounds that effectively antagonized AR F876L (and AR WT) to suppress the growth of prostate cancer cells resistant to enzalutamide. DOI: http://dx.doi.org/10.7554/eLife.00499.001 PMID:23580326

Friction and Wear of Ion-Beam-Deposited Diamondlike Carbon on Chemical-Vapor-Deposited, Fine-Grain Diamond

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Wu, Richard L. C.; Lanter, William C.

1996-01-01

Friction and wear behavior of ion-beam-deposited diamondlike carbon (DLC) films coated on chemical-vapor-deposited (CVD), fine-grain diamond coatings were examined in ultrahigh vacuum, dry nitrogen, and humid air environments. The DLC films were produced by the direct impact of an ion beam (composed of a 3:17 mixture of Ar and CH4) at ion energies of 1500 and 700 eV and an RF power of 99 W. Sliding friction experiments were conducted with hemispherical CVD diamond pins sliding on four different carbon-base coating systems: DLC films on CVD diamond; DLC films on silicon; as-deposited, fine-grain CVD diamond; and carbon-ion-implanted, fine-grain CVD diamond on silicon. Results indicate that in ultrahigh vacuum the ion-beam-deposited DLC films on fine-grain CVD diamond (similar to the ion-implanted CVD diamond) greatly decrease both the friction and wear of fine-grain CVD diamond films and provide solid lubrication. In dry nitrogen and in humid air, ion-beam-deposited DLC films on fine-grain CVD diamond films also had a low steady-state coefficient of friction and a low wear rate. These tribological performance benefits, coupled with a wider range of coating thicknesses, led to longer endurance life and improved wear resistance for the DLC deposited on fine-grain CVD diamond in comparison to the ion-implanted diamond films. Thus, DLC deposited on fine-grain CVD diamond films can be an effective wear-resistant, lubricating coating regardless of environment.

Substituent effects that control conjugated oligomer conformation through non-covalent interactions

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

Sharber, Seth A.; Baral, Rom Nath; Frausto, Fanny

Although understanding the conformations and arrangements of conjugated materials as solids is key to their prospective applications, predictive power over these structural factors remains elusive. In this work, substituent effects tune non-covalent interactions between side-chain fluorinated benzyl esters and main-chain terminal arenes, in turn controlling the conformations and interchromophore aggregation of three-ring phenylene-ethynylenes (PEs). Cofacial fluoroarene–arene (ArF–ArH) interactions cause twisting in the PE backbone, interrupting intramolecular conjugation as well as blocking chromophore aggregation, both of which prevent the typically observed bathochromic shift observed upon transitioning PEs from solution to solid. This work highlights two structural factors that determine whether themore » ArF–ArH interactions, and the resulting twisted, unaggregated chromophores, occur in these solids: (i) the electron-releasing characteristic of substituents on ArH, with more electron-releasing character favoring ArF–ArH interactions, and (ii) the fluorination pattern of the ArF ring, with 2,3,4,5,6-pentafluorophenyl favoring ArF–ArH interactions over 2,4,6-trifluorophenyl. Furthermore, these trends indicate that considerations of electrostatic complementarity, whether through a polar-π or substituent–substituent mechanism, can serve as an effective design principle in controlling the interaction strengths, and therefore the optoelectronic properties, of these molecules as solids.« less

Substituent effects that control conjugated oligomer conformation through non-covalent interactions

DOE PAGES

Sharber, Seth A.; Baral, Rom Nath; Frausto, Fanny; ...

2017-03-31

Although understanding the conformations and arrangements of conjugated materials as solids is key to their prospective applications, predictive power over these structural factors remains elusive. In this work, substituent effects tune non-covalent interactions between side-chain fluorinated benzyl esters and main-chain terminal arenes, in turn controlling the conformations and interchromophore aggregation of three-ring phenylene-ethynylenes (PEs). Cofacial fluoroarene–arene (ArF–ArH) interactions cause twisting in the PE backbone, interrupting intramolecular conjugation as well as blocking chromophore aggregation, both of which prevent the typically observed bathochromic shift observed upon transitioning PEs from solution to solid. This work highlights two structural factors that determine whether themore » ArF–ArH interactions, and the resulting twisted, unaggregated chromophores, occur in these solids: (i) the electron-releasing characteristic of substituents on ArH, with more electron-releasing character favoring ArF–ArH interactions, and (ii) the fluorination pattern of the ArF ring, with 2,3,4,5,6-pentafluorophenyl favoring ArF–ArH interactions over 2,4,6-trifluorophenyl. Furthermore, these trends indicate that considerations of electrostatic complementarity, whether through a polar-π or substituent–substituent mechanism, can serve as an effective design principle in controlling the interaction strengths, and therefore the optoelectronic properties, of these molecules as solids.« less

Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

2007-01-01

The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

alpha-Adrenergic-mediated activation of human reconstituted fibrinogen receptor (integrin alphaIIbbeta3) in Chinese hamster ovary cells.

PubMed

Butta, Nora; Larrucea, Susana; Gonzalez-Manchon, Consuelo; Alonso, Sonia; Parrilla, Roberto

2004-12-01

This work reports the functional studies of CHO cells coexpressing alpha-adrenergic (alphaAR) and human fibrinogen (Fg) receptors (integrin alphaIIbbeta3). Stimulation of these cells with alpha-agonists produced a transient rise in the free cytosolic calcium (Ca(++)) accompanied by enhanced binding to soluble Fg, and these effects were prevented by specific alphaAR antagonists. The alpha-adrenergic-induced activation of alphaIIbbeta3 in CHO-alphaIIbbeta3-alphaAR increased the rate of adhesion and extension of cells onto Fg coated plates, and also induced a soluble Fg- and alphaIIbbeta3-dependent formation of cell aggregates, whereas no effects were observed by the stimulation of CHO-alphaIIbbeta3 cells. alpha-Adrenergic antagonists, the ligand mimetic peptide RGDS, pertussis toxin (PTX), or EDTA, they all prevented the alpha-adrenergic stimulation of adhesion and aggregation. However, inhibition of PKC prevented the alpha-adrenergic stimulation of cell adherence, whereas blocking the intracellular Ca(++) mobilization impeded the stimulation of cell aggregation. The alpha-adrenergic activation was associated with phosphorylation of a protein of approximately 100 kDa and proteins of the MAPK family. The former was selectively phosphorylated by alpha-adrenergic stimulation whereas the latter were phosphorylated by the binding of cells to Fg and markedly intensified by alpha-adrenergic stimulation.

Performance evaluation of seal coat materials and designs.

DOT National Transportation Integrated Search

2011-01-01

"This project presents an evaluation of seal coat materials and design method. The primary objectives of this research are 1) to evaluate seal coat performance : from various combinations of aggregates and emulsions in terms of aggregate loss; 2) to ...

High performance, inexpensive solar cell process capable of a high degree of automation

NASA Technical Reports Server (NTRS)

Shah, P.; Fuller, C. R.

1976-01-01

This paper proposes a process for inexpensive high performance solar cell fabrication that can be automated for further cost reduction and higher throughputs. The unique feature of the process is the use of oxides as doping sources for simultaneous n(+) junction formation and back p(+) layer, as a mask for metallization and as an in situ AR coating for spectrum matching. Cost analysis is performed to show that significant cost reductions over the conventional process is possible using the proposed scheme and the cost intensive steps are identified which can be further reduced to make the process compatible with the needed price goals of 50 cents/watt. The process was demonstrated by fabricating n(+)-p cells using Arsenic doped oxides. Simple n(+)-p structure cells showed corrected efficiencies of 14.5% (AMO) and 12% with doped oxide as an in situ antireflection coating.

Laser-induced damage threshold measurements of optical dielectric coatings at lambda = 1.06 micron

NASA Astrophysics Data System (ADS)

Milev, I. Ia.; Dimov, S. S.; Terziev, D. V.; Iordanova, J. I.; Todorova, L. B.; Gelkova, A. B.

1991-10-01

The laser-induced damage thresholds for lambda = 1.06 micron of commercially available dielectric optical coatings, both antireflective and high reflectance, have been determined. The dependence of the optical coatings stability on design and selection of materials has been investigated. An improvement of the coatings durability by using nonquarterwave layers in addition to the basic design of the mirrors has been obtained. The choice of the coating materials is also discussed.

Enhanced Microwave Absorption Properties of Carbon Black/Silicone Rubber Coating by Frequency-Selective Surface

NASA Astrophysics Data System (ADS)

Yang, Zhaoning; Luo, Fa; Gao, Lu; Qing, Yuchang; Zhou, Wancheng; Zhu, Dongmei

2016-10-01

A square frequency-selective surface (FSS) design has been employed to improve the microwave absorption properties of carbon black/silicone rubber (CBSR) composite coating. The FSS is placed on the surface of the CBSR coating. The effects of FSS design parameters on the microwave absorption properties of the CBSR coating have been investigated, including the size and period of the FSS design, and the thickness and permittivity of the coating. Simulation results indicate that the absorption peak for the CBSR coating alone is related to its thickness and electromagnetic parameters, while the combination of the CBSR coating with a FSS can exhibit a new absorption peak in the reflection curve; the frequency of the new absorption peak is determined by the resonance of the square FSS design and tightly depends on the size of the squares, with larger squares in the FSS design leading to a lower frequency of the new absorption peak. The enhancement of the absorption performance depends on achievement of a new absorption peak using a suitable size and period of the FSS design. In addition, the FSS design has a stable frequency response for both transverse electromagnetic (TE) and transverse magnetic (TM) polarizations as the incident angle varies from 0° to 40°. The optimized results indicate that the bandwidth with reflection loss below -5 dB can encompass the whole frequency range from 8 GHz to 18 GHz for thickness of the CBSR coating of only 1.8 mm. The simulation results are confirmed by experiments.

Ni-Al Protective Coating of Steel Electrodes in Dc Electrolysis for Hydrogen Production / Ni-Al Pārklājuma Ietekme Uz Tērauda Elektrodiem Līdzstrāvas Elektrolīzē Ūdeņraža Ražošanai

NASA Astrophysics Data System (ADS)

Aizpurietis, P.; Vanags, M.; Kleperis, J.; Bajars, G.

2013-04-01

Hydrogen can be a good alternative to fossil fuels under the conditions of world's crisis as an effective energy carrier derived from renewable resources. Among all the known methods of hydrogen production, water electrolysis gives the ecologically purest hydrogen, so it is of importance to maximize the efficiency of this process. The authors consider the influence of plasma sprayed Ni-Al protective coating of 316L steel anode-cathode electrodes in DC electrolysis. In a long-term (24 h) process the anode corrodes strongly, losing Cr and Ni ions which are transferred to the electrolyte, while only minor corrosion of the cathode occurs. At the same time, the composition of anode and cathode electrodes protected by Ni-Al coating changes only slightly during a prolonged electrolysis. As the voltammetry and Tafel plots evidence, the Ni-Al coating protects both the anode and cathode from the corrosion and reduces the potential of hydrogen evolution. The results obtained show that such a coating works best in the case of steel electrodes. Darbā pētīts, kā līdzstrāvas elektrolīzē tērauda 316L elektrodus (anods un katods) ietekmē ar plazmas izputināšanas metodi iegūts Ni-Al pārklājums. Tikko uznestam pārklājumam ir mikrostrukturēta virsma, kas kodināšanas laikā mainās, gan pēc reljefa, gan elementu sastāva. Veicot ilgstošu (24 stundas elektrolīzi), atrasts, ka tikai tērauda elektrods anoda lomā intensīvi korodē un zaudē hroma un niķeļa jonus, kas pāriet elektrolītā, turpretī katods mainās relatīvi maz. Pārklājums Ni-Al pēc uznešanas tiek kodināts karstā sārmā, kad tiek izšķīdināta daļa sastāvā esošo elementu (Al, Si, Cd), bet ilgstošas elektrolīzes laikā pārklājuma sastāvs mainās maz gan anodam, gan katodam. Elektrodu elektroķīmiskie raksturlielumi noteikti ar voltamperometrijas un Tāfeļa līkņu analīzes metodēm. Atrasts, ka Ni-Al pārklājums aizsargā gan anodu, gan katodu no korozijas un samazina ūdeņraža izdalīšanās potenciālu, lai gan ilgstošas elektrolīzes laikā katoda pārklājumā parādās plaisas. No iegūtajiem rezultātiem ieteikts reālai elektrolīzes šūnai par anodu un katodu izmantot tēraudu, kas pārklāts ar plazmas izputināšanas metodē iegūtu Ni-Al aizsargpārklājumu.

The effect of coating patterns with spinel-based investment on the castability and porosity of titanium cast into three phosphate-bonded investments.

PubMed

Pieralini, Anelise R F; Benjamin, Camila M; Ribeiro, Ricardo Faria; Scaf, Gulnara; Adabo, Gelson Luis

2010-10-01

This study evaluated the effect of pattern coating with spinel-based investment Rematitan Ultra (RU) on the castability and internal porosity of commercially pure (CP) titanium invested into phosphate-bonded investments. The apparent porosity of the investment was also measured. Square patterns (15 × 15 × 0.3 mm(3)) were either coated with RU, or not and invested into the phosphate-bonded investments: Rematitan Plus (RP), Rema Exakt (RE), Castorit Super C (CA), and RU (control group). The castings were made in an Ar-arc vacuum-pressure machine. The castability area (mm(2) ) was measured by an image-analysis system (n = 10). For internal porosity, the casting (12 × 12 × 2 mm(3) ) was studied by the X-ray method, and the projected porous area percentage was measured by an image-analysis system (n = 10). The apparent porosity of the investment (n = 10) was measured in accordance with the ASTM C373-88 standard. Analysis of variance (One-way ANOVA) of castability was significant, and the Tukey test indicated that RU had the highest mean but the investing technique with coating increased the castability for all phosphate-bonded investments. The analysis of the internal porosity of the cast by the nonparametric test demonstrated that the RP, RE, and CA with coating and RP without coating did not differ from the control group (RU), while the CA and RE casts without coating were more porous. The one-way ANOVA of apparent porosity of the investment was significant, and the Tukey test showed that the means of RU (36.10%) and CA (37.22%) were higher than those of RP (25.91%) and RE (26.02%). Pattern coating with spinel-based material prior to phosphate-bonded investments can influence the castability and the internal porosity of CP Ti. © 2010 by The American College of Prosthodontists.

Ultraviolet optical and microstructural properties of MgF2 and LaF3 coatings deposited by ion-beam sputtering and boat and electron-beam evaporation.

PubMed

Ristau, Detlev; Günster, Stefan; Bosch, Salvador; Duparré, Angela; Masetti, Enrico; Ferré-Borrull, Josep; Kiriakidis, George; Peiró, Francesca; Quesnel, Etienne; Tikhonravov, Alexander

2002-06-01

Single layers of MgF2 and LaF3 were deposited upon superpolished fused-silica and CaF2 substrates by ion-beam sputtering (IBS) as well as by boat and electron beam (e-beam) evaporation and were characterized by a variety of complementary analytical techniques. Besides undergoing photometric and ellipsometric inspection, the samples were investigated at 193 and 633 nm by an optical scatter measurement facility. The structural properties were assessed with atomic-force microscopy, x-ray diffraction, TEM techniques that involved conventional thinning methods for the layers. For measurement of mechanical stress in the coatings, special silicon substrates were coated and analyzed. The dispersion behavior of both deposition materials, which was determined on the basis of various independent photometric measurements and data reduction techniques, is in good agreement with that published in the literature and with the bulk properties of the materials. The refractive indices of the MgF2 coatings ranged from 1.415 to 1.440 for the wavelength of the ArF excimer laser (193 nm) and from 1.435 to 1.465 for the wavelength of the F2 excimer laser (157 nm). For single layers of LaF3 the refractive indices extended from 1.67 to 1.70 at 193 nm to approximately 1.80 at 157 nm. The IBS process achieves the best homogeneity and the lowest surface roughness values (close to 1 nm(rms)) of the processes compared in the joint experiment. In contrast to MgF2 boat and e-beam evaporated coatings, which exhibit tensile mechanical stress ranging from 300 to 400 MPa, IBS coatings exhibit high compressive stress of as much as 910 MPa. A similar tendency was found for coating stress in LaF3 single layers. Experimental results are discussed with respect to the microstructural and compositional properties as well as to the surface topography of the coatings.

Ultraviolet optical and microstructural properties of MgF2 and LaF3 coatings deposited by ion-beam sputtering and boat and electron-beam evaporation

NASA Astrophysics Data System (ADS)

Ristau, Detlev; Gunster, Stefan; Bosch, Salvador; Duparre, Angela; Masetti, Enrico; Ferre-Borrull, Josep; Kiriakidis, George; Peiro, Francesca; Quesnel, Etienne; Tikhonravov, Alexander

2002-06-01

Single layers of MgF2 and LaF3 were deposited upon superpolished fused-silica and CaF2 substrates by ion-beam sputtering (IBS) as well as by boat and electron beam (e-beam) evaporation and were characterized by a variety of complementary analytical techniques. Besides undergoing photometric and ellipsometric inspection, the samples were investigated at 193 and 633 nm by an optical scatter measurement facility. The structural properties were assessed with atomic-force microscopy, x-ray diffraction, TEM techniques that involved conventional thinning methods for the layers. For measurement of mechanical stress in the coatings, special silicon substrates were coated and analyzed. The dispersion behavior of both deposition materials, which was determined on the basis of various independent photometric measurements and data reduction techniques, is in good agreement with that published in the literature and with the bulk properties of the materials. The refractive indices of the MgF2 coatings ranged from 1.415 to 1.440 for the wavelength of the ArF excimer laser (193 nm) and from 1.435 to 1.465 for the wavelength of the F2 excimer laser (157 nm). For single layers of LaF3 the refractive indices extended from 1.67 to 1.70 at 193 nm to approx1.80 at 157 nm. The IBS process achieves the best homogeneity and the lowest surface roughness values (close to 1 nmrms) of the processes compared in the joint experiment. In contrast to MgF2 boat and e-beam evaporated coatings, which exhibit tensile mechanical stress ranging from 300 to 400 MPa, IBS coatings exhibit high compressive stress of as much as 910 MPa. A similar tendency was found for coating stress in LaF3 single layers. Experimental results are discussed with respect to the microstructural and compositional properties as well as to the surface topography of the coatings.

Design and Performance Optimizations of Advanced Erosion-Resistant Low Conductivity Thermal Barrier Coatings for Rotorcraft Engines

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

2012-01-01

Thermal barrier coatings will be more aggressively designed to protect gas turbine engine hot-section components in order to meet future rotorcraft engine higher fuel efficiency and lower emission goals. For thermal barrier coatings designed for rotorcraft turbine airfoil applications, further improved erosion and impact resistance are crucial for engine performance and durability, because the rotorcraft are often operated in the most severe sand erosive environments. Advanced low thermal conductivity and erosion-resistant thermal barrier coatings are being developed, with the current emphasis being placed on thermal barrier coating toughness improvements using multicomponent alloying and processing optimization approaches. The performance of the advanced thermal barrier coatings has been evaluated in a high temperature erosion burner rig and a laser heat-flux rig to simulate engine erosion and thermal gradient environments. The results have shown that the coating composition and architecture optimizations can effectively improve the erosion and impact resistance of the coating systems, while maintaining low thermal conductivity and cyclic oxidation durability

Disruption of the Interaction of the Androgen Receptor with Chromatin: A Novel Therapeutic Approach in Prostate Cancer

DTIC Science & Technology

2016-10-01

DISTRIBUTION STATEMENT: Approved for Public Release; Distribution Unlimited The views, opinions and/or findings contained in this report are those of...interface between AR -FOXA1 plays important roles in AR responsiveness and activity. We have designed, synthesized, and tested a panel of peptides...peptidomimetics to disrupt the interaction between AR and FOXA1. The effects of these candidate compounds have been tested in multiple assays and various

Operational Implementation Design for the Earth System Prediction Capability (ESPC): A First-Look

DTIC Science & Technology

2014-02-20

Hybrid NAVDAS-AR data assimilation system assisting by providing dynamic estimates of the error in the background forecasts. 2.1.2 NAVDAS-AR – the...directly assimilates radiances from microwave radiometers and from interferometers and spectrometers in the infrared, and bending angle from Global...real-time analysis (at +3:00). Late in the 12-hr watch (around +8:00), a post-time NAVGEM/NAVDAS-AR run generates the background fields for the next

Calibration of an Ultra-Low-Background Proportional Counter for Measuring 37Ar

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

Seifert, Allen; Aalseth, Craig E.; Bonicalzi, Ricco

Abstract. An ultra-low-background proportional counter (ULBPC) design has been developed at Pacific Northwest National Laboratory (PNNL) using clean materials, primarily electrochemically-purified copper. This detector, along with an ultra-low-background counting system (ULBCS), was developed to complement a new shallow underground laboratory (30 meters water-equivalent) constructed at PNNL. The ULBCS design includes passive neutron and gamma shielding, along with an active cosmic-veto system. This system provides a capability for making ultra-sensitive measurements to support applications like age-dating soil hydrocarbons with 14C/3H, age-dating of groundwater with 39Ar, and soil-gas assay for 37Ar to support On-Site Inspection (OSI). On-Site Inspection is a key componentmore » of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclides created by an underground nuclear explosion are valuable signatures of a Treaty violation. For OSI, the 35-day half-life of 37Ar, produced from neutron interactions with calcium in soil, provides both high specific activity and sufficient time for inspection before decay limits sensitivity. This work describes the calibration techniques and analysis methods developed to enable quantitative measurements of 37Ar samples over a broad range of pressures. These efforts, along with parallel work in progress on gas chemistry separation, are expected to provide a significant new capability for 37Ar soil gas background studies.« less

Development of the ECLSS Sizing Analysis Tool and ARS Mass Balance Model Using Microsoft Excel

NASA Technical Reports Server (NTRS)

McGlothlin, E. P.; Yeh, H. Y.; Lin, C. H.

1999-01-01

The development of a Microsoft Excel-compatible Environmental Control and Life Support System (ECLSS) sizing analysis "tool" for conceptual design of Mars human exploration missions makes it possible for a user to choose a certain technology in the corresponding subsystem. This tool estimates the mass, volume, and power requirements of every technology in a subsystem and the system as a whole. Furthermore, to verify that a design sized by the ECLSS Sizing Tool meets the mission requirements and integrates properly, mass balance models that solve for component throughputs of such ECLSS systems as the Water Recovery System (WRS) and Air Revitalization System (ARS) must be developed. The ARS Mass Balance Model will be discussed in this paper.

GENE EXPRESSION ANALYSIS IN THE VENTRAL PROSTATE OF RATS EXPOSED TO VINCLOZOLIN OR PROCYMIDONE

EPA Science Inventory

Vinclozolin and procymidone are antiandrogens that are thought to share a common androgen receptor (AR) mediated mechanism of action. This assessment is based primarily on morphological, AR binding, and in vitro transcriptional activation studies. Studies designed to evaluate t...

Residency, movements and habitat use of adult white seabream (Diplodus sargus) between natural and artificial reefs

NASA Astrophysics Data System (ADS)

Abecasis, D.; Bentes, L.; Lino, P. G.; Santos, M. N.; Erzini, K.

2013-02-01

Artificial reefs are used as management tools for coastal fisheries and ecosystems and the knowledge of habitat use and fish movements around them is necessary to understand their performance and improve their design and location. In this study wild specimens of Diplodus sargus were tagged with acoustic tags and their movements were tracked using passive acoustic telemetry. The monitored area enclosed a natural rocky reef, an adjacent artificial reef (AR) and shallower sandy bottoms. Most of the fish were close to full time residents in the monitored area. Results revealed that D. sargus use the natural reef areas on a more frequent basis than the AR. However, excursions to the adjacent AR and sandy bottoms were frequently detected, essentially during daytime. The use of acoustic telemetry allowed a better understanding of the use of artificial reef structures and its adjacent areas by wild D. sargus providing information that is helpful towards the improvement of AR design and location.

Recent advancements in anti-reflective surface structures (ARSS) for near- to mid-infrared optics

NASA Astrophysics Data System (ADS)

Florea, Catalin M.; Busse, Lynda E.; Bayya, Shyam S.; Shaw, Brandon; Aggarwal, Ish D.; Sanghera, Jas S.

2013-06-01

Fused silica, YAG crystals, and spinel ceramics substrates have been successfully patterned through reactive ion etching (RIE). Reflection losses as low as 0.1% have been demonstrated for fused silica at 1.06 microns. Laser damage thresholds have been measured for substrates with ARSS and compared with uncoated and/or thin-film anti-reflection (AR) coated substrates. Thresholds as high as 100 J/cm2 have been demonstrated in fused silica with ARSS at 1.06 microns, with ARSS substrates showing improved thresholds when compared with uncoated substrates.

Effect of Argon/Oxygen Flow Rate Ratios on DC Magnetron Sputtered Nano Crystalline Zirconium Titanate Thin Films

NASA Astrophysics Data System (ADS)

Rani, D. Jhansi; Kumar, A. GuruSampath; Sarmash, T. Sofi; Chandra Babu Naidu, K.; Maddaiah, M.; Rao, T. Subba

2016-06-01

High transmitting, non absorbent, nano crystalline zirconium titanate (ZT) thin films suitable for anti reflection coatings (ARC) were deposited on to glass substrates by direct current (DC) magnetron reactive sputtering technique, under distinct Argon to Oxygen (Ar/O2) gas flow rate ratios of 31/1, 30/2, 29/3 and 28/4, with a net gas flow (Ar + O2) of 32sccm, at an optimum substrate temperature of 250°C. The influence of the gas mixture ratio on the film properties has been investigated by employing x-ray diffraction (XRD), ultra violet visible (UV-vis) spectroscopy, atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX) and four point probe methods. The films showed a predominant peak at 30.85° with (111) orientation. The crystallite size reduced from 22.94 nm to 13.5 nm and the surface roughness increased from 11.53 nm to 50.58 nm with increase in oxygen content respectively. The films deposited at 31/1 and 30/2 showed almost similar chemical composition. Increased oxygen content results an increase in electrical resistivity from 3.59 × 103 to 2.1 × 106 Ωm. The film deposited at Ar/O2 of 28/4 exhibited higher average optical transmittance of 91%, but its refractive index is higher than that of what is required for ARC. The films deposited at 31/1 and 30/2 of Ar/O2 possess higher transmittance (low absorbance) apart from suitable refractive index. Thus, these films are preferable candidates for ARC.

Augmented reality in healthcare education: an integrative review.

PubMed

Zhu, Egui; Hadadgar, Arash; Masiello, Italo; Zary, Nabil

2014-01-01

Background. The effective development of healthcare competencies poses great educational challenges. A possible approach to provide learning opportunities is the use of augmented reality (AR) where virtual learning experiences can be embedded in a real physical context. The aim of this study was to provide a comprehensive overview of the current state of the art in terms of user acceptance, the AR applications developed and the effect of AR on the development of competencies in healthcare. Methods. We conducted an integrative review. Integrative reviews are the broadest type of research review methods allowing for the inclusion of various research designs to more fully understand a phenomenon of concern. Our review included multi-disciplinary research publications in English reported until 2012. Results. 2529 research papers were found from ERIC, CINAHL, Medline, PubMed, Web of Science and Springer-link. Three qualitative, 20 quantitative and 2 mixed studies were included. Using a thematic analysis, we've described three aspects related to the research, technology and education. This study showed that AR was applied in a wide range of topics in healthcare education. Furthermore acceptance for AR as a learning technology was reported among the learners and its potential for improving different types of competencies. Discussion. AR is still considered as a novelty in the literature. Most of the studies reported early prototypes. Also the designed AR applications lacked an explicit pedagogical theoretical framework. Finally the learning strategies adopted were of the traditional style 'see one, do one and teach one' and do not integrate clinical competencies to ensure patients' safety.

Augmented reality in healthcare education: an integrative review

PubMed Central

Zhu, Egui; Hadadgar, Arash; Masiello, Italo

2014-01-01

Background. The effective development of healthcare competencies poses great educational challenges. A possible approach to provide learning opportunities is the use of augmented reality (AR) where virtual learning experiences can be embedded in a real physical context. The aim of this study was to provide a comprehensive overview of the current state of the art in terms of user acceptance, the AR applications developed and the effect of AR on the development of competencies in healthcare. Methods. We conducted an integrative review. Integrative reviews are the broadest type of research review methods allowing for the inclusion of various research designs to more fully understand a phenomenon of concern. Our review included multi-disciplinary research publications in English reported until 2012. Results. 2529 research papers were found from ERIC, CINAHL, Medline, PubMed, Web of Science and Springer-link. Three qualitative, 20 quantitative and 2 mixed studies were included. Using a thematic analysis, we’ve described three aspects related to the research, technology and education. This study showed that AR was applied in a wide range of topics in healthcare education. Furthermore acceptance for AR as a learning technology was reported among the learners and its potential for improving different types of competencies. Discussion. AR is still considered as a novelty in the literature. Most of the studies reported early prototypes. Also the designed AR applications lacked an explicit pedagogical theoretical framework. Finally the learning strategies adopted were of the traditional style ‘see one, do one and teach one’ and do not integrate clinical competencies to ensure patients’ safety. PMID:25071992

Using a Multibeam Echosounder to Monitor AN Artificial Reef

NASA Astrophysics Data System (ADS)

Tassetti, A. N.; Malaspina, S.; Fabi, G.

2015-04-01

Artificial reefs (ARs) have become popular technological interventions in shallow water environments characterized by soft seabed for a wide number of purposes, from fisheries/environmental protection and enhancement to research and tourism. AR deployment has the potential for causing significant hydrographical and biological changes in the receiving environments and, in turn, ARs are strongly affected by the surrounding area in terms of spatial arrangement and structural integrity as well as colonization by benthic communities and finfish. In this context, ARs require a systematic monitoring program that a multibeam echosounder (MBES) can provide better than other sampling methods such as visual dives and ROV inspections that are not quantitative and often influenced by water visibility and diver experience/skills. In this paper, some subsequent MBES surveys of the Senigallia scientifically-planned AR (Northern Adriatic Sea) are presented and state-of-the art data processing and visualization techniques are used to draw post-reef deployment comparisons and quantify the evolution of the reef in terms of spatial arrangement and bulk volume. These multibeam surveys play a leading part in a general multi-year program, started simultaneously with the AR design and deployment and aimed to map how the reef structure quantitatively changes over time, as well as it affects the sea-bottom morphology and the fishery resource. All the data, surveyed over years making use of different sampling methods such as visual and instrumental echosounding observations and catch rate surveys, gain a mechanistic and predictive understanding of how the Senigallia AR functions ecologically and physically across spatial and temporal scales during its design life

Iridium-Coated Rhenium Combustion Chamber

NASA Technical Reports Server (NTRS)

Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

1994-01-01

Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

Wide band design on the scaled absorbing material filled with flaky CIPs

NASA Astrophysics Data System (ADS)

Xu, Yonggang; Yuan, Liming; Gao, Wei; Wang, Xiaobing; Liang, Zichang; Liao, Yi

2018-02-01

The scaled target measurement is an important method to get the target characteristic. Radar absorbing materials are widely used in the low detectable target, considering the absorbing material frequency dispersion characteristics, it makes designing and manufacturing scaled radar absorbing materials on the scaled target very difficult. This paper proposed a wide band design method on the scaled absorbing material of the thin absorption coating with added carbonyl iron particles. According to the theoretical radar cross section (RCS) of the plate, the reflection loss determined by the permittivity and permeability was chosen as the main design factor. Then, the parameters of the scaled absorbing materials were designed using the effective medium theory, and the scaled absorbing material was constructed. Finally, the full-size coating plate and scaled coating plates (under three different scale factors) were simulated; the RCSs of the coating plates were numerically calculated and measured at 4 GHz and a scale factor of 2. The results showed that the compensated RCS of the scaled coating plate was close to that of the full-size coating plate, that is, the mean deviation was less than 0.5 dB, and the design method for the scaled material was very effective.

193 nm ArF laser ablation and patterning of chitosan thin films

NASA Astrophysics Data System (ADS)

Aesa, A. A.; Walton, C. D.

2018-06-01

This paper reports laser ablation studies on spin-coated biopolymer chitosan films, β-l,4-1inked 2-amino-2-deoxy- d-glucopyranose. Chitosan has been irradiated using an ArF laser emitting at 193 nm. An ablation threshold of F T = 85±8 mJ cm-2 has been determined from etch rate measurements. Laser-ablated chitosan is characterised using white light interferometry, scanning electron microscopy, and thermo-gravimetric analysis. Laser ablation of chitosan is discussed in terms of thermal and photoacoustic mechanisms. Heat transfer is simulated to assist in the understanding of laser-irradiated chitosan using a finite-element method and the software package COMSOL Multi-Physics™. As a demonstrator, a micro-array of square structures in the form of a crossed grating has been fabricated by laser ablation using a mask projection scanning method. The initial investigations show no evidence of thermal damage occurring to the adjacent chitosan when operating at a moderately low laser fluence of 110 mJ cm-2.

Lifetime Extension of the Gas Discharge Detectors with Plasma Etching of Silicon Deposits in 80%CF4 + 20%CO2

NASA Astrophysics Data System (ADS)

Gavrilov, G. E.; Vakhtel, V. M.; Maysuzenko, D. A.; Tavtorkina, T. A.; Fetisov, A. A.; Shvetsova, N. Yu.

2017-12-01

A method of elimination of silicon compounds from the anode wire of an aged proportional counter is presented. The aging of a counter with a 70%Ar + 30%CO2 and a 60%Ar + 30%CO2 + 10%CF4 working mixture was stimulated by a 90Sr β source. To accelerate the process of aging, the gas mixture flow to the counter was supplied through a pipe with RTV coated wall. As a result, the amplitude of the signal decreased 70% already at accumulated charge of Q = 0.03 C/cm. The etching of the silicon compounds on the wire surface with an 80%CF4 + 20%CO2 gas mixture discharge led to full recovery of the operating characteristics of detector and an increase in the lifetime. A scanning electron microscopy and X-ray spectroscopy analysis of the recovered wire surface were performed. In accordance with the results, a good quality of wire cleaning from SiO2 compounds was obtained.

Destruction of propellant magazine, November 1982

NASA Astrophysics Data System (ADS)

Tozer, N. H.

1984-08-01

Details on the destruction of a propellant magazine are given. The properties of single base propellants are discussed. Although single base propellants have been around for one hundred years, production of this type of propellant in Australia only commenced during World War 2 when appropriate plant and know how were provided under the Lend Lease Scheme. Most of the single base propellants made at Mulwala Explosives Factory have been of the IMR type i.e., single perforated tubular granules with their surface coated with DNT for use in small to medium calibre ammunition. Since production started at Mulwala Explosives Factory in 1944 some fourteen different versions of style of propellant have been manufactured. Four versions only were made up until 1957 and these were identified with an IMR type number matching the US propellants from which they were copied. New varieties introduced since 1957 have been identified with an AR aeries number commencing with AR2001 - the original Australian 7.62 mm rifle propellant.

In vitro and in vivo evaluation of ultrananocrystalline diamond as an encapsulation layer for implantable microchips.

PubMed

Chen, Ying-Chieh; Tsai, Che-Yao; Lee, Chi-Young; Lin, I-Nan

2014-05-01

Thin ultrananocrystalline diamond (UNCD) films were evaluated for use as hermetic and bioinert encapsulating coatings for implantable microchips, where the reaction to UNCD in vitro and in vivo tissue was investigated. Leakage current tests showed that depositing UNCD coatings, which were conformally grown in (1% H2) Ar/CH4 plasma, on microchips rendered the surface electrochemically inactive, i.e. with a very low leakage current density (2.8×10(-5)Acm(-2) at -1V and 1.9×10(-3)Acm(-2) at ±5V) ex vivo. The impact of UNCD with different surface modifications on the growth and activation of macrophages was compared to that of standard-grade polystyrene. Macrophages attached to oxygen-terminated UNCD films down-regulated their production of cytokines and chemokines. Moreover, with UNCD-coated microchips, which were implanted subcutaneously into BALB/c mice for up to 3months, the tissue reaction and capsule formation was significantly decreased compared to the medical-grade titanium alloy Ti-6Al-4V and bare silicon. Additionally, the leakage current density, elicited by electrochemical activity, on silicon chips encapsulated in oxygen-terminated UNCD coatings remained at the low level of 2.5×10(-3)Acm(-2) at 5V for up to 3months in vivo, which is half the level of those encapsulated in hydrogen-terminated UNCD coatings. Thus, controlling the surface properties of UNCDs makes it possible to manipulate the in vivo functionality and stability of implantable devices so as to reduce the host inflammatory response following implantation. These observations suggest that oxygen-terminated UNCDs are promising candidates for use as encapsulating coatings for implantable microelectronic devices. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

International Space Station Program Phase 3 Integrated Atmosphere Revitalization Subsystem Test

NASA Technical Reports Server (NTRS)

Perry, J. L.; Franks, G. D.; Knox, J. C.

1997-01-01

Testing of the International Space Station (ISS) U.S. Segment baseline configuration of the Atmosphere Revitalization Subsystem (ARS) by NASA's Marshall Space Flight Center (MSFC) was conducted as part of the Environmental Control and Life Support System (ECLSS) design and development program. This testing was designed to answer specific questions regarding the control and performance of the baseline ARS subassemblies in the ISS U.S. Segment configuration. These questions resulted from the continued maturation of the ISS ECLSS configuration and design requirement changes since 1992. The test used pressurized oxygen injection, a mass spectrometric major constituent analyzer, a Four-Bed Molecular Sieve Carbon Dioxide Removal Assembly, and a Trace Contaminant Control Subassembly to maintain the atmospheric composition in a sealed chamber at ISS specifications for 30 days. Human metabolic processes for a crew of four were simulated according to projected ISS mission time lines. The performance of a static feed water electrolysis Oxygen Generator Assembly was investigated during the test preparation phases; however, technical difficulties prevented its use during the integrated test. The Integrated ARS Test (IART) program built upon previous closed-door and open-door integrated testing conducted at MSFC between 1987 and 1992. It is the most advanced test of an integrated ARS conducted by NASA to demonstrate its end-to-end control and overall performance. IART test objectives, facility design, pretest analyses, test and control requirements, and test results are presented.

40 CFR 60.740 - Applicability and designation of affected facility.

Code of Federal Regulations, 2010 CFR

2010-07-01

... fraction; (3) Web coating operations that print an image on the surface of the substrate or any coating... coating operation and any onsite coating mix preparation equipment used to prepare coatings for the... coatings at one plant for shipment to another plant for use in an affected facility (coating operation) or...

Effects of antibiotic resistance (AR) and microbiota shifts on Campylobacter jejuni-mediated diseases.

PubMed

Brooks, Phillip T; Mansfield, Linda S

2017-12-01

Campylobacter jejuni is an important zoonotic pathogen recently designated a serious antimicrobial resistant (AR) threat. While most patients with C. jejuni experience hemorrhagic colitis, serious autoimmune conditions can follow including inflammatory bowel disease (IBD) and the acute neuropathy Guillain Barré Syndrome (GBS). This review examines inter-relationships among factors mediating C. jejuni diarrheal versus autoimmune disease especially AR C. jejuni and microbiome shifts. Because both susceptible and AR C. jejuni are acquired from animals or their products, we consider their role in harboring strains. Inter-relationships among factors mediating C. jejuni colonization, diarrheal and autoimmune disease include C. jejuni virulence factors and AR, the enteric microbiome, and host responses. Because AR C. jejuni have been suggested to affect the severity of disease, length of infections and propensity to develop GBS, it is important to understand how these interactions occur when strains are under selection by antimicrobials. More work is needed to elucidate host-pathogen interactions of AR C. jejuni compared with susceptible strains and how AR C. jejuni are maintained and evolve in animal reservoirs and the extent of transmission to humans. These knowledge gaps impair the development of effective strategies to prevent the emergence of AR C. jejuni in reservoir species and human populations.

Update to the USDA-ARS fixed-wing spray nozzle models

USDA-ARS?s Scientific Manuscript database

The current USDA ARS Aerial Spray Nozzle Models were updated to reflect both new standardized measurement methods and systems, as well as, to increase operational spray pressure, aircraft airspeed and nozzle orientation angle limits. The new models were developed using both Central Composite Design...

Structural Diversity of Ligand-Binding Androgen Receptors Revealed by Microsecond Long Molecular Dynamics Simulations and Enhanced Sampling.

PubMed

Duan, Mojie; Liu, Na; Zhou, Wenfang; Li, Dan; Yang, Minghui; Hou, Tingjun

2016-09-13

Androgen receptor (AR) plays important roles in the development of prostate cancer (PCa). The antagonistic drugs, which suppress the activity of AR, are widely used in the treatment of PCa. However, the molecular mechanism of antagonism about how ligands affect the structures of AR remains elusive. To better understand the conformational variability of ARs bound with agonists or antagonists, we performed long time unbiased molecular dynamics (MD) simulations and enhanced sampling simulations for the ligand binding domain of AR (AR-LBD) in complex with various ligands. Based on the simulation results, we proposed an allosteric pathway linking ligands and helix 12 (H12) of AR-LBD, which involves the interactions among the ligands and the residues W741, H874, and I899. The interaction pathway provides an atomistic explanation of how ligands affect the structure of AR-LBD. A repositioning of H12 was observed, but it is facilitated by the C-terminal of H12, instead of by the loop between helix 11 (H11) and H12. The bias-exchange metadynamics simulations further demonstrated the above observations. More importantly, the free energy profiles constructed by the enhanced sampling simulations revealed the transition process between the antagonistic form and agonistic form of AR-LBD. Our results would be helpful for the design of more efficient antagonists of AR to combat PCa.

Reflection/suppression coatings for 900 - 1200 A radiation

NASA Technical Reports Server (NTRS)

Edelstein, Jerry

1989-01-01

The design and performance of multiple-layer, selective-reflection, selective-suppression coatings for the 900 - 1200 A band are described. These coatings are designed to optimize both high reflectivity at a desirable wavelength and low reflectivity at an undesirable wavelength. The minimum structure for a selective coating consists of a thin metal or metal oxide layer (50 - 150 A thickness) over an aluminum substrate protected with a semi-transparent dielectric (100 - 1000 A thickness). Predicted coating performance is strongly effected by varying the layer combination and thickness. A graphical method of optimizing the coating layer structure is developed. Aluminum, silicon, their oxides, and gold have been investigated as coating layer materials. A very simple coating with a 1026 to 1216 A reflectivity ratio greater than 100 was fabricated. Such reflection/suppression coatings may be of great utility to spaceborne EUV spectrographs.

A Multifunctional Coating for Autonomous Corrosion Control

NASA Technical Reports Server (NTRS)

Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

2011-01-01

Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

Bacillus sp. CDB3 isolated from cattle dip-sites possesses two ars gene clusters.

PubMed

Bhat, Somanath; Luo, Xi; Xu, Zhiqiang; Liu, Lixia; Zhang, Ren

2011-01-01

Contamination of soil and water by arsenic is a global problem. In Australia, the dipping of cattle in arsenic-containing solution to control cattle ticks in last centenary has left many sites heavily contaminated with arsenic and other toxicants. We had previously isolated five soil bacterial strains (CDB1-5) highly resistant to arsenic. To understand the resistance mechanism, molecular studies have been carried out. Two chromosome-encoded arsenic resistance (ars) gene clusters have been cloned from CDB3 (Bacillus sp.). They both function in Escherichia coli and cluster 1 exerts a much higher resistance to the toxic metalloid. Cluster 2 is smaller possessing four open reading frames (ORFs) arsRorf2BC, similar to that identified in Bacillus subtilis Skin element. Among the eight ORFs in cluster 1 five are analogs of common ars genes found in other bacteria, however, organized in a unique order arsRBCDA instead of arsRDABC. Three other putative genes are located directly downstream and designated as arsTIP based on the homologies of their theoretical translation sequences respectively to thioredoxin reductases, iron-sulphur cluster proteins and protein phosphatases. The latter two are novel of any known ars operons. The arsD gene from Bacillus species was cloned for the first time and the predict protein differs from the well studied E. coli ArsD by lacking two pairs of C-terminal cysteine residues. Its functional involvement in arsenic resistance has been confirmed by a deletion experiment. There exists also an inverted repeat in the intergenic region between arsC and arsD implying some unknown transcription regulation.

Allergic rhinitis and inflammatory airway disease: interactions within the unified airspace.

PubMed

Marple, Bradley F

2010-01-01

Allergic rhinitis (AR), the most common chronic allergic condition in outpatient medicine, is associated with immense health care costs and socioeconomic consequences. AR's impact may be partly from interacting of respiratory conditions via allergic inflammation. This study was designed to review potential interactive mechanisms of AR and associated conditions and consider the relevance of a bidirectional "unified airway" respiratory inflammation model on diagnosis and treatment of inflammatory airway disease. MEDLINE was searched for pathophysiology and pathophysiological and epidemiologic links between AR and diseases of the sinuses, lungs, middle ear, and nasopharynx. Allergic-related inflammatory responses or neural and systemic processes fostering inflammatory changes distant from initial allergen provocation may link AR and comorbidities. Treating AR may benefit associated respiratory tract comorbidities. Besides improving AR outcomes, treatment inhibiting eosinophil recruitment and migration, normalizing cytokine profiles, and reducing asthma-associated health care use in atopic subjects would likely ameliorate other upper airway diseases such as acute rhinosinusitis, chronic rhinosinusitis (CRS) with nasal polyposis (NP), adenoidal hypertrophy, and otitis media with effusion. Epidemiological concordance of AR with several airway diseases conforms to a bidirectional "unified airway" respiratory inflammation model based on anatomic and histological upper and lower airway connections. Epidemiology and current understanding of inflammatory, humoral, and neural processes make links between AR and disorders including asthma, otitis media, NP, and CRS plausible. Combining AR with associated conditions increases disease burden; worsened associated illness may accompany worsened AR. AR pharmacotherapies include antihistamines, leukotriene antagonists, intranasal corticosteroids, and immunotherapy; treatments attenuating proinflammatory responses may also benefit associated conditions.

Atmospheric pressure cold plasma treatment of cellulose based fillers for wood plastic composites

NASA Astrophysics Data System (ADS)

Lekobou, William; Englund, Karl; Pedrow, Patrick; Scudiero, Louis

2011-10-01

The main challenge of wood plastic composites (WPC) resides in the low interfacial adhesion due to incompatibility between the cellulose based filler that has a polar surface and most common matrixes, polyolefins which are non-polar. Plasma treatment is a promising technique for surface modification and its implementation into the processing of WPC would provide this industry with a versatile and nearly environmentally benign manufacturing tool. Our investigation aims at designing a cold atmospheric pressure plasma reactor for coating fillers with a hydrophobic material prior to compounding with the matrix. Deposition was achieved with our reactor that includes an array of high voltage needles, a grounded metal mesh, Ar as carrier gas and C2H2 as the precursor molecule. Parameters studied have included gas feed rates and applied voltage; FTIR, ESCA, AFM and SEM imaging were used for film diagnostics. We will also report on deposition rate and its dependence on radial and axial position as well as the effects of plasma-polymerized acetylene on the surface free energy of cellulose based substrates.

Field experiment of 800× off-axis XR-Köhler concentrator module on a carousel tracker

NASA Astrophysics Data System (ADS)

Yamada, Noboru; Okamoto, Kazuya; Ijiro, Toshikazu; Suzuki, Takao; Maemura, Toshihiko; Kawaguchi, Takashi; Takahashi, Hiroshi; Sato, Takashi; Hernandez, Maikel; Benitez, Pablo; Chaves, Julio; Cvetkovic, Aleksandra; Vilaplana, Juan; Mohedano, Ruben; Mendes-Lopes, Joao; Miñano, Juan Carlos

2013-09-01

This paper presents the design and preliminary experimental results of a concentrator-type photovoltaic module based on a free-form off-axis 800×XR-Köhler concentrator. The off-axis XR-Köhler concentrator is one of the advanced concentrators that perform high concentration with a large acceptance angle and excellent irradiance uniformity on a solar cell. As a result of on-sun characterization of the unglazed single-cell unit test rig, the temperature-corrected DC module efficiency was 32.2% at 25 °C without an anti-reflective (AR) coating on the secondary optics, and the acceptance angle was more than ±1.0°. In addition, the non-corrected DC efficiency of an individual cell in a glazed 8-cell unit module mounted on a carousel tracking system was measured. The individual efficiency deviated in the range of 24.3-27.4%, owing to the mirror shape and alignment errors. The resultant series-connected efficiency was approximately 25% at direct normal irradiation (DNI) of 770 W/m2.

Application of a tablet film coating model to define a process-imposed transition boundary for robust film coating.

PubMed

van den Ban, Sander; Pitt, Kendal G; Whiteman, Marshall

2018-02-01

A scientific understanding of interaction of product, film coat, film coating process, and equipment is important to enable design and operation of industrial scale pharmaceutical film coating processes that are robust and provide the level of control required to consistently deliver quality film coated product. Thermodynamic film coating conditions provided in the tablet film coating process impact film coat formation and subsequent product quality. A thermodynamic film coating model was used to evaluate film coating process performance over a wide range of film coating equipment from pilot to industrial scale (2.5-400 kg). An approximate process-imposed transition boundary, from operating in a dry to a wet environment, was derived, for relative humidity and exhaust temperature, and used to understand the impact of the film coating process on product formulation and process control requirements. This approximate transition boundary may aid in an enhanced understanding of risk to product quality, application of modern Quality by Design (QbD) based product development, technology transfer and scale-up, and support the science-based justification of critical process parameters (CPPs).

Design colloidal particle morphology and self-assembly for coating applications

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

Jiang, Shan; Van Dyk, Antony; Maurice, Alvin

The progressive replacement of organic solvent-based coatings by waterborne latex polymer coatings has substantially renovated the coating industry, and generated huge environmental and health benefits. Today, on top of the continuing demand for higher performance and lower costs, the coating industry faces tighter regulation and higher sustainability standards. In addition, the new waterborne coatings have created unique opportunities and challenges in terms of fundamental understanding and research development. To address these challenges, polymer latex binders with diverse particle morphologies have been developed to improve coating performance. Furthermore, colloidal self-assembly has been utilized to help manufacturers make better paint with lessmore » cost. In this report, we review the recent progress in both fundamental study and industrial application in the context of developing new generation architectural coating materials. We introduce the basic concepts in coating materials and showcase several key technologies that have been implemented to improve coating performance. As a result, these technologies also represent the most important considerations in architectural coating design.« less

Design colloidal particle morphology and self-assembly for coating applications

DOE PAGES

Jiang, Shan; Van Dyk, Antony; Maurice, Alvin; ...

2017-05-04

The progressive replacement of organic solvent-based coatings by waterborne latex polymer coatings has substantially renovated the coating industry, and generated huge environmental and health benefits. Today, on top of the continuing demand for higher performance and lower costs, the coating industry faces tighter regulation and higher sustainability standards. In addition, the new waterborne coatings have created unique opportunities and challenges in terms of fundamental understanding and research development. To address these challenges, polymer latex binders with diverse particle morphologies have been developed to improve coating performance. Furthermore, colloidal self-assembly has been utilized to help manufacturers make better paint with lessmore » cost. In this report, we review the recent progress in both fundamental study and industrial application in the context of developing new generation architectural coating materials. We introduce the basic concepts in coating materials and showcase several key technologies that have been implemented to improve coating performance. As a result, these technologies also represent the most important considerations in architectural coating design.« less

Communicative Elements of Action Research

ERIC Educational Resources Information Center

Ryan, Thomas G.

2013-01-01

This review considers human communications as utilized within a research design; in this case collaborative action research (CAR), a derivative of action research (AR), to achieve outcomes that change, and move participants forward. The association between AR and CAR is a deliberate attempt by the author to draw attention to communicative actions…

Examining Young Children's Perception toward Augmented Reality-Infused Dramatic Play

ERIC Educational Resources Information Center

Han, Jeonghye; Jo, Miheon; Hyun, Eunja; So, Hyo-jeong

2015-01-01

Amid the increasing interest in applying augmented reality (AR) in educational settings, this study explores the design and enactment of an AR-infused robot system to enhance children's satisfaction and sensory engagement with dramatic play activities. In particular, we conducted an exploratory study to empirically examine children's perceptions…

ADDING GLOBAL SOILS DATA TO THE AUTOMATED GEOSPATIAL WATERSHED ASSESSMENT TOOL (AGWA)

EPA Science Inventory

The Automated Geospatial Watershed Assessment Tool (AGWA) is a GIS-based hydrologic modeling tool that is available as an extension for ArcView 3.x from the USDA-ARS Southwest Watershed Research Center (www.tucson.ars.ag.gov/agwa). AGWA is designed to facilitate the assessment of...

CACAO (THEOBROMA CACAO L.) GENETIC RESOURCES RESEARCH AT THE USDA-ARS TROPICAL AGRICULTURE RESEARCH STATION

USDA-ARS?s Scientific Manuscript database

The current USDA ARS Tropical Agriculture Research Station’s cacao (Theobroma cacao) collection consists of 154 clonally propagated accessions. Each accession is represented by six individual trees grafted on Amelonado rootstocks and planted in a completely randomized block design with three blocks...

Targeting the adaptive molecular landscape of castration-resistant prostate cancer

PubMed Central

Wyatt, Alexander W; Gleave, Martin E

2015-01-01

Castration and androgen receptor (AR) pathway inhibitors induce profound and sustained responses in advanced prostate cancer. However, the inevitable recurrence is associated with reactivation of the AR and progression to a more aggressive phenotype termed castration-resistant prostate cancer (CRPC). AR reactivation can occur directly through genomic modification of the AR gene, or indirectly via co-factor and co-chaperone deregulation. This mechanistic heterogeneity is further complicated by the stress-driven induction of a myriad of overlapping cellular survival pathways. In this review, we describe the heterogeneous and evolvable molecular landscape of CRPC and explore recent successes and failures of therapeutic strategies designed to target AR reactivation and adaptive survival pathways. We also discuss exciting areas of burgeoning anti-tumour research, and their potential to improve the survival and management of patients with CRPC. PMID:25896606

Effects of thermal loading and hydrostatic pressure on reflecting wavelengths of double-coated fiber Bragg grating with different coating-layer thickness

NASA Astrophysics Data System (ADS)

Seraji, Faramarz E.; Toutian, Golnoush

2017-10-01

Fiber Bragg grating (FBG) of different configurations used as sensing devices are vulnerable to environmental factors, such as static pressures and thermal loading, which cause their characteristic Bragg reflecting wavelengths to up/down-shift. In this paper, by considering double-coated FBG with different primary and secondary coating materials, the effects of thermal loading and hydrostatic pressure on FBG with different coating-layer thicknesses are analyzed to find design criteria for controlling the Bragg wavelength shift. The obtained results of the analysis may be employed as criteria to design pressure and temperature sensors when using double-coated FBGs.

Pushing the Limits of Broadband and High-Frequency Metamaterial Silicon Antireflection Coatings

NASA Astrophysics Data System (ADS)

Coughlin, K. P.; McMahon, J. J.; Crowley, K. T.; Koopman, B. J.; Miller, K. H.; Simon, S. M.; Wollack, E. J.

2018-05-01

Broadband refractive optics realized from high-index materials provide compelling design solutions for the next generation of observatories for the cosmic microwave background and for sub-millimeter astronomy. In this paper, work is presented which extends the state of the art in silicon lenses with metamaterial antireflection coatings toward larger-bandwidth and higher-frequency operation. Examples presented include octave bandwidth coatings with less than 0.5% reflection, a prototype 4:1 bandwidth coating, and a coating optimized for 1.4 THz. For these coatings, the detailed design, fabrication and testing processes are described as well as the inherent performance trade-offs.

Ceramic thermal barrier coatings for commercial gas turbine engines

NASA Technical Reports Server (NTRS)

Meier, Susan Manning; Gupta, Dinesh K.; Sheffler, Keith D.

1991-01-01

The paper provides an overview of the short history, current status, and future prospects of ceramic thermal barrier coatings for gas turbine engines. Particular attention is given to plasma-sprayed and electron beam-physical vapor deposited yttria-stabilized (7 wt pct Y2O3) zirconia systems. Recent advances include improvements in the spallation life of thermal barrier coatings, improved bond coat composition and spraying techniques, and improved component design. The discussion also covers field experience, life prediction modeling, and future directions in ceramic coatings in relation to gas turbine engine design.

Recent Development of IMP LECR3 Ion Source

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

Zhang, Z.M.; Zhao, H.W.; Li, J.Y.

2005-03-15

18GHz microwave has been fed to the LECR3 ion source to produce intense highly charged ion beams although this ion source was designed for 14.5GHz. Then 1.1 emA Ar8+ and 325 e{mu}A Ar11+ were obtained at 18GHz. During the source running for atomic physics experiment, some higher charge state ion beams such as Ar17+ and Ar18+ were detected and have been validated by atomic physics method. Furthermore, a few special gases, e.g. SiH4 and SF6, were tested on LECR3 ion source to produce required ion beams to satisfy the requirements of atomic physics experiments.

Design and Lithographic Characteristics of Alicyclic Fluoropolymer for ArF Chemically Amplified Resists

NASA Astrophysics Data System (ADS)

Maeda, Katsumi; Nakano, Kaichiro; Shirai, Masamitsu

2006-12-01

We designed a novel alicyclic fluoropolymer, poly[3-hydroxy-4-(hexafluoro-2-hydroxyisopropyl)tricyclodecene], as an ArF (193 nm) chemically amplified resist. This fluoropolymer has a hexafluoroisopropanol group as an alkaline soluble unit and a hydroxyl group for improving adhesion. This polymer also exhibited a high transparency of 93%/150 nm at 193 nm, high thermal stability (355 °C), and a good adhesion to a Si substrate compared with a poly(norbornene) with a hexafluoroisopropanol group. The etching rate of our developed fluoropolymer for CF4 gas was 1.29 times that of the KrF resist. Moreover, a chemically amplified positive resist comprising an ethoxymethyl-protected polymer and a photoacid generator achieved a 110 nm line-and-space pattern with an ArF exposure.

Growth Inhibition by Testosterone in an Androgen Receptor Splice Variant-Driven Prostate Cancer Model.

PubMed

Nakata, Daisuke; Nakayama, Kazuhide; Masaki, Tsuneo; Tanaka, Akira; Kusaka, Masami; Watanabe, Tatsuya

2016-12-01

Castration resistance creates a significant problem in the treatment of prostate cancer. Constitutively active splice variants of androgen receptor (AR) have emerged as drivers for resistance to androgen deprivation therapy, including the next-generation androgen-AR axis inhibitors abiraterone and enzalutamide. In this study, we describe the characteristics of a novel castration-resistant prostate cancer (CRPC) model, designated JDCaP-hr (hormone refractory). JDCaP-hr was established from an androgen-dependent JDCaP xenograft model after surgical castration. The expression of AR and its splice variants in JDCaP-hr was evaluated by immunoblotting and quantitative reverse transcription-polymerase chain reaction. The effects of AR antagonists and testosterone on JDCaP-hr were evaluated in vivo and in vitro. The roles of full-length AR (AR-FL) and AR-V7 in JDCaP-hr cell growth were evaluated using RNA interference. JDCaP-hr acquired a C-terminally truncated AR protein during progression from the parental JDCaP. The expression of AR-FL and AR-V7 mRNA was upregulated by 10-fold in JDCaP-hr compared with that in JDCaP, indicating that the JDCaP and JDCaP-hr models simulate castration resistance with some clinical features, such as overexpression of AR and its splice variants. The AR antagonist bicalutamide did not affect JDCaP-hr xenograft growth, and importantly, testosterone induced tumor regression. In vitro analysis demonstrated that androgen-independent prostate-specific antigen secretion and cell proliferation of JDCaP-hr were predominantly mediated by AR-V7. JDCaP-hr cell growth displayed a bell-shaped dependence on testosterone, and it was suppressed by physiological concentrations of testosterone. Testosterone induced rapid downregulation of both AR-FL and AR-V7 expression at physiological concentrations and suppressed expression of the AR target gene KLK3. Our findings support the clinical value of testosterone therapy, including bipolar androgen therapy, in the treatment of AR-overexpressed CRPC driven by AR splice variants that are not clinically actionable at present. Prostate 76:1536-1545, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Concurrent Use of an Audience Response System at a Multi-Campus College of Pharmacy

PubMed Central

Alkhateeb, Fadi M.; Singh-Franco, Devada

2012-01-01

Objective. To assess the impact of an audience response system (ARS) on student engagement at a multi-campus college of pharmacy. Methods. An online questionnaire was designed and administered to measure the impact of an ARS on student engagement, distance education, projected use, and satisfaction among pharmacy students for a course delivered across 3 sites via synchronous video transmission. Results. Students reported that use of the ARS made it easier to participate (85.3%) and helped them to focus (75.7%) in classes when the lecturer was physically at a different site. They also valued that the ARS allowed them to respond anonymously (93.2%). A minority of students indicated that use of the ARS was distracting (11.8%). Conclusions. Implementation of an ARS was associated with positive student perceptions of engagement and may improve feelings of connectedness among students at schools with multiple sites. Use of ARSs could also represent a cognitive intercession strategy to help reduce communication apprehension. PMID:22412205

ArF halftone PSM cleaning process optimization for next-generation lithography

NASA Astrophysics Data System (ADS)

Son, Yong-Seok; Jeong, Seong-Ho; Kim, Jeong-Bae; Kim, Hong-Seok

2000-07-01

ArF lithography which is expected for the next generation optical lithography is adapted for 0.13 micrometers design-rule and beyond. ArF half-tone phase shift mask (HT PSM) will be applied as 1st generation of ArF lithography. Also ArF PSM cleaning demands by means of tighter controls related to phase angle, transmittance and contamination on the masks. Phase angle on ArF HT PSM should be controlled within at least +/- 3 degree and transmittance controlled within at least +/- 3 percent after cleaning process and pelliclization. In the cleaning process of HT PSM, requires not only the remove the particle on mask, but also control to half-tone material for metamorphosis. Contamination defects on the Qz of half tone type PSM is not easy to remove on the photomask surface. New technology and methods of cleaning will be developed in near future, but we try to get out for limit contamination on the mask, without variation of phase angle and transmittance after cleaning process.

Directing driver attention with augmented reality cues

PubMed Central

Rusch, Michelle L.; Schall, Mark C.; Gavin, Patrick; Lee, John D.; Dawson, Jeffrey D.; Vecera, Shaun; Rizzo, Matthew

2013-01-01

This simulator study evaluated the effects of augmented reality (AR) cues designed to direct the attention of experienced drivers to roadside hazards. Twenty-seven healthy middle-aged licensed drivers with a range of attention capacity participated in a 54 mile (1.5 hour) drive in an interactive fixed-base driving simulator. Each participant received AR cues to potential roadside hazards in six simulated straight (9 mile long) rural roadway segments. Drivers were evaluated on response time for detecting a potentially hazardous event, detection accuracy for target (hazard) and non-target objects, and headway with respect to the hazards. Results showed no negative outcomes associated with interference. AR cues did not impair perception of non-target objects, including for drivers with lower attentional capacity. Results showed near significant response time benefits for AR cued hazards. AR cueing increased response rate for detecting pedestrians and warning signs but not vehicles. AR system false alarms and misses did not impair driver responses to potential hazards. PMID:24436635

Investigation of Collision-Induced Fluorescence in D2:Ar and D2:HD:Ar Mixtures at 200 k,

DTIC Science & Technology

1985-07-01

a total density of 730 amagat. (One amagat is the density at STP.) Due to various practical difficulties associated with the design of a potential...any laser design . The pulse duration is required to be short compared with the vibrational lifetime, but not short enough to give problems with...laser action of the gas media investigated. 2. M EPERIMENTAL ARRANGEMENT The experimental arrangement is shown in Fig. 1. The output of the hydrogen

Novel Junction-specific and Quantifiable In Situ Detection of AR-V7 and its Clinical Correlates in Metastatic Castration-resistant Prostate Cancer.

PubMed

Zhu, Yezi; Sharp, Adam; Anderson, Courtney M; Silberstein, John L; Taylor, Maritza; Lu, Changxue; Zhao, Pei; De Marzo, Angelo M; Antonarakis, Emmanuel S; Wang, Mindy; Wu, Xingyong; Luo, Yuling; Su, Nan; Nava Rodrigues, Daniel; Figueiredo, Ines; Welti, Jonathan; Park, Emily; Ma, Xiao-Jun; Coleman, Ilsa; Morrissey, Colm; Plymate, Stephen R; Nelson, Peter S; de Bono, Johann S; Luo, Jun

2018-05-01

Androgen receptor splice variant 7 (AR-V7) has been implicated in resistance to abiraterone and enzalutamide treatment in men with metastatic castration-resistant prostate cancer (mCRPC). Tissue- or cell-based in situ detection of AR-V7, however, has been limited by lack of specificity. To address current limitations in precision measurement of AR-V7 by developing a novel junction-specific AR-V7 RNA in situ hybridization (RISH) assay compatible with automated quantification. We designed a RISH method to visualize single splice junctions in cells and tissue. Using the validated assay for junction-specific detection of the full-length AR (AR-FL) and AR-V7, we generated quantitative data, blinded to clinical data, for 63 prostate tumor biopsies. We evaluated clinical correlates of AR-FL/AR-V7 measurements, including association with prostate-specific antigen progression-free survival (PSA-PFS) and clinical and radiographic progression-free survival (PFS), in a subset of patients starting treatment with abiraterone or enzalutamide following biopsy. Quantitative AR-FL/AR-V7 data were generated from 56 of the 63 (88.9%) biopsy specimens examined, of which 44 were mCRPC biopsies. Positive AR-V7 signals were detected in 34.1% (15/44) mCRPC specimens, all of which also co-expressed AR-FL. The median AR-V7/AR-FL ratio was 11.9% (range 2.7-30.3%). Positive detection of AR-V7 was correlated with indicators of high disease burden at baseline. Among the 25 CRPC biopsies collected before treatment with abiraterone or enzalutamide, positive AR-V7 detection, but not higher AR-FL, was significantly associated with shorter PSA-PFS (hazard ratio 2.789, 95% confidence interval 1.12-6.95; p=0.0081). We report for the first time a RISH method for highly specific and quantifiable detection of splice junctions, allowing further characterization of AR-V7 and its clinical significance. Higher AR-V7 levels detected and quantified using a novel method were associated with poorer response to abiraterone or enzalutamide in prostate cancer. Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Design and performance of the VLT 8-m coating unit

NASA Astrophysics Data System (ADS)

Schneermann, Michael W.; Groessl, M.; Nienaber, U.; Ettlinger, E.; Spiteri, J. A.; Clow, H.

1997-03-01

The 8 m coating unit for the VLT mirrors is designed for the deposition of high reflective, homogeneous aluminum coatings. For the process of the film deposition the sputter technology is utilized. The design of the following major subsystems is completed: the vacuum vessel and the vacuum generation system, the thin film deposition equipment and the glow discharge cleaning device, the substrate support and rotation system as well as the supporting framework and the auxiliary equipment. Manufacturing of the coating unit has started. The pre- assembly and testing activities, which will take place prior to the shipment to the site, are defined. This paper describes the design features and the major performance requirements of the 8 m coating unit. The performance of the sputter source design has been verified in a qualification test. The deposition rate, the film thickness and reflectance, as well as the film purity have been measured. The test set-up and the results of the qualification tests of the selected magnetron type are presented and discussed.

Homeostasis and secretion of calcium in the oviductal mucosa of toad Rhinella arenarum.

PubMed

Crespo, Claudia A; Medina, Marcela F; Ramos, Inés; Fernández, Silvia N

2014-10-01

The presence of a calcium pump, calbindin D-28KD, and calmodulin in the secretory cells (SC) of the oviductal pars convoluta (PC) of Rhinella arenarum was established for the first time in amphibians using immunohistochemical techniques. Marked variations were observed in the localization and degree of expression of these proteins according to the duct segment and the period of the sexual cycle analyzed. During the preovulatory and ovulatory periods the calcium pump colocalized with calbindin D-28KD can be seen mainly in the apical border of the SC, which are located in the first zones of PC and synthesize and secrete the components of the inner jelly coat layers. These envelopes, which surround the oocytes, contain the molecules indispensable for fertilization, probably inducing the sperm acrosome reaction (AR). Our results suggest that calmodulin, colocalized with the calcium pump at the SC cytoplasmic level, would be involved in the active transport of the cation inside the secretory granules, maintaining adequate levels of intracellular Ca(2+) . During the postreproductive period, a calcium pump colocalized with calbindin D-28KD appears for the first time in the cycle in the basal zones of the SC. This system may be related to the replenishing of intracellular Ca(2+) stores. In contrast, in R. arenarum the Ca(2+) present in the jelly coats that surround the oocytes participates in the AR during fertilization, suggesting that this secretion system of the cation provided by the oviductal mucosa is functionally more active during the reproductive period of this species. © 2014 Wiley Periodicals, Inc.

Angular circulation speed of tablets in a vibratory tablet coating pan.

PubMed

Kumar, Rahul; Wassgren, Carl

2013-03-01

In this work, a single tablet model and a discrete element method (DEM) computer simulation are developed to obtain the angular circulation speed of tablets in a vibratory tablet coating pan for range of vibration frequencies and amplitudes. The models identify three important dimensionless parameters that influence the speed of the tablets: the dimensionless amplitude ratio (a/R), the Froude number (aω2/g), and the tablet-wall friction coefficient, where a is the peak vibration amplitude at the drum center, ω is the vibration angular frequency, R is the drum radius, and g is the acceleration due to gravity. The models predict that the angular circulation speed of tablets increases with an increase in each of these parameters. The rate of increase in the angular circulation speed is observed to decrease for larger values of a/R. The angular circulation speed reaches an asymptote beyond a tablet-wall friction coefficient value of about 0.4. Furthermore, it is found that the Froude number should be greater than one for the tablets to start circulating. The angular circulation speed increases as Froude number increases but then does not change significantly at larger values of the Froude number. Period doubling, where the motion of the bed is repeated every two cycles, occurs at a Froude number larger than five. The single tablet model, although much simpler than the DEM model, is able to predict the maximum circulation speed (the limiting case for a large value of tablet-wall friction coefficient) as well as the transition to period doubling.

14-3-3η Amplifies Androgen Receptor Actions in Prostate Cancer

PubMed Central

Titus, Mark A.; Tan, Jiann-an; Gregory, Christopher W.; Ford, O. Harris; Subramanian, Romesh R.; Fu, Haian; Wilson, Elizabeth M.; Mohler, James L.; French, Frank S.

2009-01-01

Purpose Androgen receptor (AR) abundance and AR-regulated gene expression in castration-recurrent prostate cancer (CaP) are indicative of AR activation in the absence of testicular androgen. AR transactivation of target genes in castration-recurrent CaP occurs in part through mitogen signaling that amplifies the actions of AR and its coregulators. Herein we report on the role of 14-3-3η in AR action. Experimental Design and Results AR and 14-3-3η co-localized in COS cell nuclei with and without androgen and 14-3-3η promoted AR nuclear localization in the absence of androgen. 14-3-3η interacted with AR in cell-free binding and coimmunoprecipitation assays. In the recurrent human CaP cell line, CWR-R1, native endogenous AR transcriptional activation was stimulated by 14-3-3η at low DHT concentrations and was increased by EGF. Moreover, the DHT and EGF dependent increase in AR transactivation was inhibited by a dominant negative 14-3-3η. In the CWR22 CaP xenograft model, 14-3-3η expression was increased by androgen, suggesting a feed-forward mechanism that potentiates both 14-3-3η and AR actions. 14-3-3η mRNA and protein decreased following castration of tumor bearing mice and increased in tumors of castrate mice after treatment with testosterone. CWR22 tumors that recurred 5 months after castration contained 14-3-3η levels similar to the androgen-stimulated tumors removed before castration. In a human prostate tissue microarray of clinical specimens, 14-3-3η localized with AR in nuclei and the similar amounts expressed in castration-recurrent CaP, androgen-stimulated CaP and benign prostatic hyperplasia were consistent with AR activation in recurrent CaP. Conclusion 14-3-3η enhances androgen and mitogen induced AR transcriptional activity in castration-recurrent CaP. PMID:19996220

Study of the effect of the silver content on the structural and mechanical behavior of Ag-ZrCN coatings for orthopedic prostheses.

PubMed

Ferreri, I; Lopes, V; Calderon V, S; Tavares, C J; Cavaleiro, A; Carvalho, S

2014-09-01

With the increase of elderly population and health problems that are arising nowadays, hip joint prostheses are being widely used. However, it is estimated that 20% of hip replacement surgeries simply fails after few years, mainly due to wear fatigue. Bearing this in mind, this work reports on the development of new coatings that are able to sustain long and innocuous life inside the patient, which will confer to the usual biomaterials improved physical, mechanical and tribological properties. In particular, the development of multifunctional coatings based on Ag-ZrCN, prepared by DC reactive magnetron sputtering using two targets, Zr and a modified Zr target, in an Ar+C2H2+N2 atmosphere. Silver pellets were placed in the erosion area of the alloyed Zr target in order to obtain a silver content up to 8 at.%. The structural results obtained by x-ray diffraction show that the coatings crystallize in a NaCl crystal structure typical of ZrC1-xNx. The increase of Ag content promoted the formation of an additional a-CNx amorphous phase, besides a silver crystalline phase. Hardness is decreasing, as increasing silver content. Despite the low thicknesses, adhesion values (LC3) can be considered as good. Dynamic fatigue results suggest that these coatings system can be a real asset in terms of mechanical properties, by improving the performance of usual Stainless Steel 316 L biomaterials. Copyright © 2014 Elsevier B.V. All rights reserved.

40 CFR 59.101 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... promote a faster cure of an enamel finish. Impact-resistant coating means a coating designed to resist... in its original solvent. Low-gloss coating means a coating which exhibits a gloss reading less than...

40 CFR 59.101 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... promote a faster cure of an enamel finish. Impact-resistant coating means a coating designed to resist... in its original solvent. Low-gloss coating means a coating which exhibits a gloss reading less than...

Ergonomics action research I: shifting from hypothesis testing to experiential learning.

PubMed

Neumann, W P; Dixon, S M; Ekman, M

2012-01-01

This paper presents the case for the need for 'Action Research' (AR) approaches to gain understanding of how ergonomics considerations can best be integrated into the design of new work systems. The AR researchers work collaboratively with other stakeholders to solve a real-world problem: gaining insight into the problem and factors influencing solution building from an embedded position in the development process. This experience is interpreted in terms of available theory and can support further theory development. This non-experimental approach can help provide practical new approaches for integrating ergonomics considerations into real work system design processes. The AR approach suffers from a lack of acceptance by conventionally trained scientists. This paper aims to help overcome this weakness by developing the underlying theory and rationale for using AR approaches in ergonomics research. We propose further development of hybrid approaches which incorporate other evaluation techniques to extend the knowledge gains from AR projects. Researchers should engage directly with organisations in ergonomics projects so that they can better understand the challenges and needs of practitioners who are trying to apply available scientific knowledge in their own unique context. Such 'Action Research' could help develop theory and approaches useful to improve mobilisation and application of ergonomics knowledge in organisations.

Detection of anabolic androgenic steroid abuse in doping control using mammalian reporter gene bioassays.

PubMed

Houtman, Corine J; Sterk, Saskia S; van de Heijning, Monique P M; Brouwer, Abraham; Stephany, Rainer W; van der Burg, Bart; Sonneveld, Edwin

2009-04-01

Anabolic androgenic steroids (AAS) are a class of steroid hormones related to the male hormone testosterone. They are frequently detected as drugs in sport doping control. Being similar to or derived from natural male hormones, AAS share the activation of the androgen receptor (AR) as common mechanism of action. The mammalian androgen responsive reporter gene assay (AR CALUX bioassay), measuring compounds interacting with the AR can be used for the analysis of AAS without the necessity of knowing their chemical structure beforehand, whereas current chemical-analytical approaches may have difficulty in detecting compounds with unknown structures, such as designer steroids. This study demonstrated that AAS prohibited in sports and potential designer AAS can be detected with this AR reporter gene assay, but that also additional steroid activities of AAS could be found using additional mammalian bioassays for other types of steroid hormones. Mixtures of AAS were found to behave additively in the AR reporter gene assay showing that it is possible to use this method for complex mixtures as are found in doping control samples, including mixtures that are a result of multi drug use. To test if mammalian reporter gene assays could be used for the detection of AAS in urine samples, background steroidal activities were measured. AAS-spiked urine samples, mimicking doping positive samples, showed significantly higher androgenic activities than unspiked samples. GC-MS analysis of endogenous androgens and AR reporter gene assay analysis of urine samples showed how a combined chemical-analytical and bioassay approach can be used to identify samples containing AAS. The results indicate that the AR reporter gene assay, in addition to chemical-analytical methods, can be a valuable tool for the analysis of AAS for doping control purposes.

An industrial approach to design compelling VR and AR experience

NASA Astrophysics Data System (ADS)

Richir, Simon; Fuchs, Philippe; Lourdeaux, Domitile; Buche, Cédric; Querrec, Ronan

2013-03-01

The convergence of technologies currently observed in the field of VR, AR, robotics and consumer electronic reinforces the trend of new applications appearing every day. But when transferring knowledge acquired from research to businesses, research laboratories are often at a loss because of a lack of knowledge of the design and integration processes in creating an industrial scale product. In fact, the innovation approaches that take a good idea from the laboratory to a successful industrial product are often little known to researchers. The objective of this paper is to present the results of the work of several research teams that have finalized a working method for researchers and manufacturers that allow them to design virtual or augmented reality systems and enable their users to enjoy "a compelling VR experience". That approach, called "the I2I method", present 11 phases from "Establishing technological and competitive intelligence and industrial property" to "Improvements" through the "Definition of the Behavioral Interface, Virtual Environment and Behavioral Software Assistance". As a result of the experience gained by various research teams, this design approach benefits from contributions from current VR and AR research. Our objective is to validate and continuously move such multidisciplinary design team methods forward.

Low Group Delay Dispersion Optical Coating for Broad Bandwidth High Reflection at 45° Incidence, P Polarization of Femtosecond Pulses with 900 nm Center Wavelength

DOE PAGES

Bellum, John C.; Field, Ella S.; Winstone, Trevor B.; ...

2016-03-01

We describe an optical coating design suitable for broad bandwidth high reflection (BBHR) at 45° angle of incidence (AOI), P polarization (Ppol) of femtosecond (fs) laser pulses whose wavelengths range from 800 to 1000 nm. The design process is guided by quarter-wave HR coating properties. Our design must afford low group delay dispersion (GDD) for reflected light over the broad, 200 nm bandwidth in order to minimize temporal broadening of the fs pulses due to dispersive alteration of relative phases between their frequency components. The design should also be favorable to high laser-induced damage threshold (LIDT). We base the coatingmore » on TiO 2/SiO 2 layer pairs produced by means of e-beam evaporation with ion-assisted deposition, and use OptiLayer Thin Film Software to explore designs starting with TiO 2/SiO 2 layers having thicknesses in a reverse chirped arrangement. This approach led to a design with R > 99% from 800 to 1000 nm and GDD < 20 fs 2 from 843 to 949 nm (45° AOI, Ppol). The design’s GDD behaves in a smooth way, suitable for GDD compensation techniques, and its electric field intensities show promise for high LIDTs. Reflectivity and GDD measurements for the initial test coating indicate good performance of the BBHR design. Subsequent coating runs with improved process calibration produced two coatings whose HR bands satisfactorily meet the design goals. Lastly, for the sake of completeness, we summarize our previously reported transmission spectra and LIDT test results with 800 ps, 8 ps and 675 fs pulses for these two coatings, and present a table of the LIDT results we have for all of our TiO 2/SiO 2 BBHR coatings, showing the trends with test laser pulse duration from the ns to sub-ps regimes.« less

7 CFR 3201.98 - Wastewater systems coatings.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 15 2014-01-01 2014-01-01 false Wastewater systems coatings. 3201.98 Section 3201.98... Designated Items § 3201.98 Wastewater systems coatings. (a) Definition. Coatings that protect wastewater... procurement preference for qualifying biobased wastewater systems coatings. By that date, Federal agencies...

7 CFR 3201.98 - Wastewater systems coatings.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 15 2013-01-01 2013-01-01 false Wastewater systems coatings. 3201.98 Section 3201.98... Designated Items § 3201.98 Wastewater systems coatings. (a) Definition. Coatings that protect wastewater... procurement preference for qualifying biobased wastewater systems coatings. By that date, Federal agencies...

[Quantitative evaluation of acrylic and silicone intraocular lenses with a sharp optic edge design].

PubMed

Rabsilber, T M; Reuland, A J; Entz, B B; Holzer, M P; Limberger, I J; Auffarth, G U

2006-01-01

At the Department of Ophthalmology, Heidelberg, Germany, posterior capsule opacification (PCO) of a silicone and an acrylic intraocular lens (IOL) with a sharp optic edge design was evaluated. In a prospective study either the AMO ClariFlex silicone IOL or the Sensar AR40e hydrophobic acrylic IOL were implanted in 47 patients following uneventful phacoemulsification. Mean patient age was 76.2+/-7.8 (ClariFlex) and 73.4+/-12.9 years (AR40e), respectively. The mean follow-up time was 19.7+/-5.34 in the ClariFlex and 21.9+/-1.89 months in the AR40e group. PCO development was evaluated postoperatively using the EPCO 2000 analysis software (scale 0-4). Areas of interest were the total IOL optic, the central 3-mm zone as well as the capsulorhexis. In both groups, all patients achieved a BCVA of 20/32 (AR40e) and 20/25 (ClariFlex), respectively. There was a very low incidence of PCO development with a mean EPCO score of 0.07+/-0.2 (ClariFlex and 0.15+/-0.2 (AR40e). Within the 3-mm zone and the capsulorhexis, there was a tendency for even lower EPCO scores in both groups. We calculated a statistically significant difference for the two lens materials for all investigated IOL areas (Wilcoxon's test, p<0.05). Both IOLs with a sharp edge design showed good functional results, a stable position in the capsular bag as well as a low incidence of PCO development. However, the silicone IOL showed statistically significantly lower PCO scores.

Androgen receptor mitigates postoperative disease progression of hepatocellular carcinoma by suppressing CD90+ populations and cell migration and by promoting anoikis in circulating tumor cells

PubMed Central

Lai, Hsueh-Chou; Yeh, Chun-Chieh; Jeng, Long-Bin; Huang, Shang-Fen; Liao, Pei-Ying; Lei, Fu-Ju; Cheng, Wei-Chun; Hsu, Cheng-Lung; Cai, Xiujun; Chang, Chawnshang; Ma, Wen-Lung

2016-01-01

Purpose Although hepatectomy and liver transplantation surgery for hepatocellular carcinoma (HCC) are effective treatment modalities, the risk of recurrence remains high, particularly in patients with a high number of circulating tumor cells (CTCs) expressing cancer stem/progenitor cell markers. Androgen receptor (AR) signaling has been shown to suppress HCC metastasis in rodent models of HCC. In this study, we investigated whether AR is associated with postoperative HCC recurrence. Experimental Design CTCs were obtained from patients with HCC who had undergone hepatectomy to investigate whether they are associated with disease outcome. AR knockout was introduced in two mouse models of spontaneous HCC (carcinogen- and hepatitis B virus-related HCC) to delineate the role that AR plays in HCC recurrence. Biological systems analysis was used to investigate the cellular and molecular mechanisms. Results We found that the expression of AR in CTCs was negatively associated with HCC recurrence/progression after hepatectomy. Our results suggest that AR-mediated suppression of HCC recurrence/progression is governed by a three-pronged mechanism. First, AR suppresses the expression of CD90 in CTCs by upregulating Histone 3H2A. Second, AR suppresses cell migration at the transcriptome level. Third, AR promotes anoikis of CTCs via dysregulation of cytoskeletal adsorption. Conclusions The results indicate that AR expression may be the gatekeeper of postoperative HCC recurrence. Therefore, targeting AR in presurgical down-staging procedures may serve as a secondary prevention measure against HCC recurrence in the future. PMID:27340775

Burden of allergic rhinitis: allergies in America, Latin America, and Asia-Pacific adult surveys.

PubMed

Meltzer, Eli O; Blaiss, Michael S; Naclerio, Robert M; Stoloff, Stuart W; Derebery, M Jennifer; Nelson, Harold S; Boyle, John M; Wingertzahn, Mark A

2012-01-01

Allergic rhinitis (AR; also nasal allergies or "hay fever") is a chronic upper airway inflammatory disease that affects ∼60 million adults and children in the United States. The duration and severity of AR symptoms contribute to a substantial burden on patients' quality of life (QoL), sleep, work productivity, and activity. This study was designed to examine symptoms, QoL, productivity, comorbidities, disease management, and pharmacologic treatment of AR in United States and ex-U.S. sufferers. Allergies in America was a comprehensive telephone-based survey of 2500 adults with AR. These data are compared and contrasted with findings from the Pediatric Allergies in America, Allergies in Latin America, and Allergies in Asia-Pacific telephone surveys. The prevalence of physician-diagnosed AR was 14% in U.S. adults, 7% in Latin America adults, and 9% in Asia-Pacific adults. Nasal congestion is the most common and bothersome symptom for adults. Approximately two-thirds of adults rely on medication to relieve intolerable AR symptoms. Incomplete relief, slow onset, <24-hour relief, and reduced efficacy with sustained use were commonly reported with AR medications, including intranasal corticosteroids. One in seven U.S. adults reported achieving little to no relief with AR medications. Bothersome adverse effects of AR medications included drowsiness, a drying feeling, medication dripping down the throat, and bad taste. Perception of inadequate efficacy was the leading cause of medication discontinuation or change and contributed to treatment dissatisfaction. These findings support the assertion that AR burden has been substantially underestimated and identify several important challenges to successful management of AR.

Interaction of the androgen receptor, ETV1 and PTEN pathways in mouse prostate varies with pathological stage and predicts cancer progression

PubMed Central

Higgins, Jake; Brogley, Michele; Palanisamy, Nallasivam; Mehra, Rohit; Ittmann, Michael M.; Li, Jun Z.; Tomlins, Scott A.; Robins, Diane M.

2015-01-01

To examine the impact of common somatic mutations in prostate cancer (PCa) on androgen receptor (AR) signaling, mouse models were designed to perturb sequentially the AR, ETV1 and PTEN pathways. Mice with "humanized" AR (hAR) alleles that modified AR transcriptional strength by varying polyglutamine tract (Q-tract) length were crossed with mice expressing a prostate-specific, AR-responsive ETV1 transgene (ETV1Tg). While hAR allele did not grossly affect ETV1-induced neoplasia, ETV1 strongly antagonized global AR regulation and repressed critical androgen-induced differentiation and tumor suppressor genes, such as Nkx3-1 and Hoxb13. When Pten was varied to determine its impact on disease progression, mice lacking one Pten allele (Pten+/−) developed more frequent prostatic intraepithelial neoplasia (PIN). Yet only those with the ETV1 transgene progressed to invasive adenocarcinoma. Furthermore, progression was more frequent with the short Q-tract (stronger) AR, suggesting that the AR, ETV1 and PTEN pathways cooperate in aggressive disease. On the Pten+/− background, ETV1 had markedly less effect on AR target genes. However, a strong inflammatory gene expression signature, notably upregulation of Cxcl16, was induced by ETV1. Comparison of mouse and human patient data stratified by presence of ETS fusion genes highlighted additional factors, some not previously associated with prostate cancer but for which targeted therapies are in development for other diseases. In sum, concerted use of these mouse models illuminates the complex interplay of AR, ETV1 and PTEN pathways in pre-cancerous neoplasia and early tumorigenesis, disease stages difficult to analyze in man. PMID:25631336

Articulation Research System: A New Direction in Curriculum Evaluation. User's Manual.

ERIC Educational Resources Information Center

Gilbert, Russell; Delaino, G. Thomas

This user's manual explains the Articulation Research System (ARS), which was created by Santa Fe Community College, and its database. As introductory material notes, the ARS was designed to: (1) follow former community college students through their bachelor's degree programs in the Florida State University System (SUS); (2) compare student…

Social Augmented Reality: Enhancing Context-Dependent Communication and Informal Learning at Work

ERIC Educational Resources Information Center

Pejoska, Jana; Bauters, Merja; Purma, Jukka; Leinonen, Teemu

2016-01-01

Our design proposal of social augmented reality (SoAR) grows from the observed difficulties of practical applications of augmented reality (AR) in workplace learning. In our research we investigated construction workers doing physical work in the field and analyzed the data using qualitative methods in various workshops. The challenges related to…

The Design of Immersive English Learning Environment Using Augmented Reality

ERIC Educational Resources Information Center

Li, Kuo-Chen; Chen, Cheng-Ting; Cheng, Shein-Yung; Tsai, Chung-Wei

2016-01-01

The study uses augmented reality (AR) technology to integrate virtual objects into the real learning environment for language learning. The English AR classroom is constructed using the system prototyping method and evaluated by semi-structured in-depth interviews. According to the flow theory by Csikszenmihalyi in 1975 along with the immersive…

Tantalum coatings for inertial confinement fusion dry wall designs

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

Taylor, L.H.; Green, L.

1996-12-31

The coating on a dry first wall inertial confinement fusion reactor must survive the target explosion and be ductile, inexpensive, and compatible with the materials in the target, i.e. have a high atomic number Z. Calculations indicate that tantalum is the best choice for the coating material. As a test of this design 1 mm tantalum coatings were plasma sprayed onto ferrite steel tubes. They were then subjected to 100 heating-cooling cycles which simulated the stressful thermal cycling which would be encountered during five years of plant startups and shutdowns. The coatings were undamaged and continued to bond well tomore » the steel. Furthermore, chemical reactions should not degrade tantalum coatings.« less

An improved design method and experimental performance of two dimensional curved wall diffusers

NASA Technical Reports Server (NTRS)

Yang, T.; Hudson, W. G.; El-Nashar, A. M.

1972-01-01

A computer design program was developed to incorporate the suction slots in solving the potential flow equations with prescribed boundary conditions. Using the contour generated from this program two Griffith diffusers were tested having area ratios AR = 3 and 4. The inlet Reynolds number ranged from 600,000 to 7 million. It was found that the slot suction required for metastable operation depends on the sidewall suction applied. Values of slot suction of 8% of the inlet flow rate was required for AR = 4 with metastable condition, provided that enough sidewall suction was applied. For AR = 3, the values of slot suction was about 25% lower than those required for AR = 4. For nearly all unseparated test runs, the effectiveness was 100% and the exit flow was uniform. In addition to the Griffith diffusers, dump and cusp diffusers of comparable area ratios were built and tested. The results obtained from these diffusers were compared with those of the Griffith diffusers. Flow separation occurred in all test runs with the dump and cusp diffusers.

Response surface methodological approach for the decolorization of simulated dye effluent using Aspergillus fumigatus fresenius.

PubMed

Sharma, Praveen; Singh, Lakhvinder; Dilbaghi, Neeraj

2009-01-30

The aim of our research was to study, effect of temperature, pH and initial dye concentration on decolorization of diazo dye Acid Red 151 (AR 151) from simulated dye solution using a fungal isolate Aspergillus fumigatus fresenius have been investigated. The central composite design matrix and response surface methodology (RSM) have been applied to design the experiments to evaluate the interactive effects of three most important operating variables: temperature (25-35 degrees C), pH (4.0-7.0), and initial dye concentration (100-200 mg/L) on the biodegradation of AR 151. The total 20 experiments were conducted in the present study towards the construction of a quadratic model. Very high regression coefficient between the variables and the response (R(2)=0.9934) indicated excellent evaluation of experimental data by second-order polynomial regression model. The RSM indicated that initial dye concentration of 150 mg/L, pH 5.5 and a temperature of 30 degrees C were optimal for maximum % decolorization of AR 151 in simulated dye solution, and 84.8% decolorization of AR 151 was observed at optimum growth conditions.

Stabilizing IkappaBalpha by "consensus" design.

PubMed

Ferreiro, Diego U; Cervantes, Carla F; Truhlar, Stephanie M E; Cho, Samuel S; Wolynes, Peter G; Komives, Elizabeth A

2007-01-26

IkappaBalpha is the major regulator of transcription factor NF-kappaB function. The ankyrin repeat region of IkappaBalpha mediates specific interactions with NF-kappaB dimers, but ankyrin repeats 1, 5 and 6 display a highly dynamic character when not in complex with NF-kappaB. Using chemical denaturation, we show here that IkappaBalpha displays two folding transitions: a non-cooperative conversion under weak perturbation, and a major cooperative folding phase upon stronger insult. Taking advantage of a native Trp residue in ankyrin repeat (AR) 6 and engineered Trp residues in AR2, AR4 and AR5, we show that the cooperative transition involves AR2 and AR3, while the non-cooperative transition involves AR5 and AR6. The major structural transition can be affected by single amino acid substitutions converging to the "consensus" ankyrin repeat sequence, increasing the native state stability significantly. We further characterized the structural and dynamic properties of the native state ensemble of IkappaBalpha and the stabilized mutants by H/(2)H exchange mass spectrometry and NMR. The solution experiments were complemented with molecular dynamics simulations to elucidate the microscopic origins of the stabilizing effect of the consensus substitutions, which can be traced to the fast conformational dynamics of the folded ensemble.

Evaluation of an audience response system in a preclinical operative dentistry course.

PubMed

Elashvili, Ana; Denehy, Gerald E; Dawson, Deborah V; Cunningham, Marsha A

2008-11-01

Student performance was compared on written and psychomotor skill tests of freshman dental students receiving conventional lectures versus the same lectures containing interactive components using TurningPoint, a wireless audience response system (ARS). The research design was a controlled crossover study with seventy-seven freshman dental students conducted in a preclinical operative dentistry course. Two randomized groups alternated the two study lectures, one with ARS and the other without ARS. Student knowledge retention was measured through written examination using immediate posttest, as well as questions on the unit and final examinations. Psychomotor skill tests were given on both lecture topics. Statistically significant differences indicating superiority of ARS were identified for performance on the immediate posttest and psychomotor skill test only for the lecture "Principles of Dental Bonding." The other examinations/skill testing showed no significant difference. These results indicate that ARS is a promising teaching tool for dental education.

Observation of interspecies ion separation in inertial-confinement-fusion implosions

DOE PAGES

Hsu, Scott C.; Joshi, Tirtha Raj; Hakel, Peter; ...

2016-10-24

Here we report direct experimental evidence of interspecies ion separation in direct-drive, inertial-confinement-fusion experiments on the OMEGA laser facility. These experiments, which used plastic capsules with D 2/Ar gas fill (1% Ar by atom), were designed specifically to reveal interspecies ion separation by exploiting the predicted, strong ion thermo-diffusion between ion species of large mass and charge difference. Via detailed analyses of imaging x-ray-spectroscopy data, we extract Ar-atom-fraction radial profiles at different times, and observe both enhancement and depletion compared to the initial 1%-Ar gas fill. The experimental results are interpreted with radiation-hydrodynamic simulations that include recently implemented, first-principles modelsmore » of interspecies ion diffusion. Finally, the experimentally inferred Ar-atom-fraction profiles agree reasonably, but not exactly, with calculated profiles associated with the incoming and rebounding first shock.« less

Mechanical properties of pulsed laser-deposited hydroxyapatite thin films implanted at high energy with N + and Ar + ions. Part II: nano-scratch tests with spherical tipped indenter

NASA Astrophysics Data System (ADS)

Pelletier, H.; Nelea, V.; Mille, P.; Muller, D.

2004-02-01

In this study we report a method to improve the adherence of hydroxyapatite (HA) thin films, using an ion beam implantation treatment. Crystalline HA films were grown by pulsed laser deposition technique (PLD), using an excimer KrF * laser. The films were deposited at room temperature in vacuum on Ti-5Al-2.5Fe alloy substrates previously coated with a ceramic TiN buffer layer and then annealed in ambient air at (500-600) °C. After deposition the films were implanted with N + and Ar + ions accelerated at high energy (1-1.5 MeV range) at a fixed dose of 10 16 cm -2. The intrinsic mechanical resistance and adherence to the TiN buffer layer of the implanted HA films have been evaluated by nano-scratch tests. We used for measurements a spherical indenter with a tip radius of 5 μm. Different scratch tests have been performed on implanted and unimplanted areas of films to put into evidence the effects of N + and Ar + ion implantation process on the films properties. Results show an enhancement of the dynamic mechanical properties in the implanted zones and influence of the nature of the implanted species. The best results are obtained for films implanted with nitrogen.

A&R challenges for in-space operations. [Automation and Robotic technologies

NASA Technical Reports Server (NTRS)

Underwood, James

1990-01-01

Automation and robotics (A&R) challenges for in-space operations are examined, with emphasis on the interaction between developing requirements, developing solutions, design concepts, and the nature of the applicability of automation in robotic technologies. Attention is first given to the use of A&R in establishing outposts on the moon and Mars. Then emphasis is placed on the requirements for the assembly of transportation systems in low earth orbit. Concepts of the Space Station which show how the assembly, processing, and checkout of systems in LEO might be accommodated are examined.

Near zero reflection by nanostructured anti-reflection coating design for Si substrates

NASA Astrophysics Data System (ADS)

Al-Fandi, Mohamed; Makableh, Yahia F.; Khasawneh, Mohammad; Rabady, Rabi

2018-05-01

The nanostructure design of near zero reflection coating for Si substrates by using ZnO Nanoneedles (ZnONN) is performed and optimized for the visible spectral range. The design investigates the ZnONN tip to body ratio effect on the anti-reflection coating properties. Different tip to body ratios are used on Si substrates. Around zero reflection is achieved by the Nanoneedles structure design presented in this work, leading to minimal reflection losses from the Si surface. The current design evolves a solution to optical losses and surface contamination effects associated with Si solar cells.

Mechanistic Study on Cu(II)-Catalyzed Oxidative Cross-Coupling Reaction between Arenes and Boronic Acids under Aerobic Conditions.

PubMed

Zhang, Qian; Liu, Yang; Wang, Ting; Zhang, Xinhao; Long, Chao; Wu, Yun-Dong; Wang, Mei-Xiang

2018-04-25

Substantial attention has been given to modern organocopper chemistry in recent years since copper salts are naturally abundant, cheap, and less toxic in comparison to precious metals. Copper salts also exhibit versatility in catalyzing and mediating carbon-carbon and carbon-heteroatom bond forming reactions. Despite the wide applications of copper salts in catalysis, reaction mechanisms have remained elusive. Using azacalix[1]arene[3]pyridine, an arene-embedded macrocycle, and its isolated and structurally well-defined ArCu(II) and ArCu(III) compounds as molecular tools, we now report an in-depth experimental and computational study on the mechanism of a Cu(II)-catalyzed oxidative cross-coupling reaction between arenes and boronic acids with air as the oxidant. Stoichiometric reaction of organocopper compounds with p-tolylboronic acid validated arylcopper(II) rather than arylcopper(III) as a reactive organometallic intermediate. XPS, EPR, 1 H NMR, HRMS, and UV-vis spectroscopic evidence along with the isolation and quantification of all products and copper speciation, combined with computational analysis of the electronic structure and energetics of the transient intermediates, suggested a reaction sequence involving electrophilic metalation of arene by Cu(II), transmetalation of arylboronate to ArCu(II), the redox reaction between the resulting ArCu(II)Ar' and ArCu(II) to form respectively ArCu(III)Ar' and ArCu(I), and finally reductive elimination of ArCu(III)Ar'. Under aerobic catalytic conditions, all Cu(I) ions released from reductive elimination of ArCu(III)Ar' and from protolysis of ArCu(I) were oxidized by oxygen to regenerate Cu(II) species that enters into the next catalytic cycle. The unraveled reactivity of arylcopper(II) compounds and the catalytic cycle would enrich our knowledge of modern organocopper chemistry and provide useful information in the design of copper-catalyzed reactions.

CgA1AR-1 acts as an alpha-1 adrenergic receptor in oyster Crassostrea gigas mediating both cellular and humoral immune response.

PubMed

Liu, Zhaoqun; Zhou, Zhi; Wang, Lingling; Qiu, Limei; Zhang, Huan; Wang, Hao; Song, Linsheng

2016-11-01

We have now cloned an alpha-1 adrenergic receptor (A1AR) from the cDNA library of oyster Crassostrea gigas, designating as CgA1AR-1. The full length of CgA1AR-1 was 1149 bp and it encodes a protein of 382 amino acids containing a 7 transmembrane domain, whose putative topology was similar to the A1ARs in higher organisms and shared similarity of 19% with mammalian A1ARs according to the phylogenic analysis. After cell transfection of CgA1AR-1 into HEK293T cells and the incubation with its specific agonist norepinephrine (NE), the concentration of second messenger Ca 2+ increased significantly (p < 0.05). But, this increasing of Ca 2+ could be inhibited by adding A1AR antagonist DOX. Tissue distribution assays using qRT-PCR suggested that CgA1AR-1 mRNA was ubiquitously expressed in all the major tissues of oyster. LPS stimulation could induce the up-regulation of CgA1AR-1 mRNA in haemocytes from 12 h to 24 h post stimulation. Moreover, the blocking of CgA1AR-1 by DOX before LPS stimulation affected the mRNA expression of oyster TNF (CGI_10005109 and CGI_10006440) in haemocytes, resulting in the rise of haemocyte phagocytic rate and apoptosis index. In addition to cellular immunity, CgA1AR-1 was also involved in humoral immunity of oyster. Inhibition of CgA1AR-1 with DOX could repress the up-regulation of LZY and SOD activities caused by LPS stimulation. These results suggested that CgA1AR-1 acted as an α-1 adrenergic receptor in cetacholaminergic neuroendocrine-immune network mediating both cellular and humoral immune response. Copyright © 2016 Elsevier Ltd. All rights reserved.

Branched Chain RNA In Situ Hybridization for Androgen Receptor Splice Variant AR-V7 as a Prognostic Biomarker for Metastatic Castration-Sensitive Prostate Cancer.

PubMed

Saylor, Philip J; Lee, Richard J; Arora, Kshitij S; Deshpande, Vikram; Hu, Rong; Olivier, Kara; Meneely, Erika; Rivera, Miguel N; Ting, David T; Wu, Chin-Lee; Miyamoto, David T

2017-01-15

The androgen receptor (AR) mRNA splice variant AR-V7 has emerged as a predictive biomarker for response to AR-targeted therapies. There are currently no commercially available assays to detect AR splice variants. The branched chain RNA in situ hybridization (ISH) platform enables the highly sensitive detection of RNA transcripts in formalin-fixed, paraffin-embedded (FFPE) tissues. We designed a branched chain RNA ISH probe to target the unique cryptic exon CE3 of AR-V7 using multiple tiling probes. This automated ISH assay was applied to tumor tissue from two distinct clinical cohorts that we hypothesized would differ in AR-V7 status. We detected AR-V7 in all tumor samples from men with metastatic castration-resistant prostate cancer with tissue obtained after disease progression despite at least one subsequent line of hormonal therapy (abiraterone, enzalutamide, or bicalutamide; n = 12). We detected AR-V7 in just one tumor from men who had undergone prostatectomy for localized adenocarcinoma (n = 30; Gleason 4 + 5 = 9 in the AR-V7-positive sample). Given the apparent distinction between the above groups by AR-V7 signal, we analyzed pretreatment AR-V7 status as a predictive and prognostic biomarker in men with treatment-naïve metastatic disease. Patients with metastases but without detectable AR-V7 RNA at baseline had significantly longer overall survival (log-rank P = 0.044) and a trend toward superior progression-free survival (log-rank P = 0.055). Within an institutional cohort, the RNA ISH assay identified AR-V7 within FFPE tissue and may have prognostic value in metastatic castration-sensitive prostate cancer. These preliminary findings warrant further study in larger cohorts. Clin Cancer Res; 23(2); 363-9. ©2016 AACR. ©2016 American Association for Cancer Research.

Life modeling of thermal barrier coatings for aircraft gas turbine engines

NASA Technical Reports Server (NTRS)

Miller, R. A.

1989-01-01

Thermal barrier coating life models developed under the NASA Lewis Research Center's Hot Section Technology (HOST) Program are summarized. An initial laboratory model and three design-capable models are discussed. Current understanding of coating failure mechanisms are also summarized. The materials and structural aspects of thermal barrier coatings have been successfully integrated under the HOST program to produce models which may now or in the near future be used in design. Efforts on this program continue at Pratt and Whitney Aircraft where their model is being extended to the life prediction of physical vapor deposited thermal barrier coatings.

Effect of Layer-Graded Bond Coats on Edge Stress Concentration and Oxidation Behavior of Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Ghosn, Louis J.; Miller, Robert A.

1998-01-01

Thermal barrier coating (TBC) durability is closely related to design, processing and microstructure of the coating Z, tn systems. Two important issues that must be considered during the design of a thermal barrier coating are thermal expansion and modulus mismatch between the substrate and the ceramic layer, and substrate oxidation. In many cases, both of these issues may be best addressed through the selection of an appropriate bond coat system. In this study, a low thermal expansion and layer-graded bond coat system, that consists of plasma-sprayed FeCoNiCrAl and FeCrAlY coatings, and a high velocity oxyfuel (HVOF) sprayed FeCrAlY coating, is developed to minimize the thermal stresses and provide oxidation resistance. The thermal expansion and oxidation behavior of the coating system are also characterized, and the strain isolation effect of the bond coat system is analyzed using the finite element method (FEM). Experiments and finite element results show that the layer-graded bond coat system possesses lower interfacial stresses. better strain isolation and excellent oxidation resistance. thus significantly improving the coating performance and durability.

Interfaces - Weak Links, Yet Great Opportunities

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Dimofte, Florin; Chupp, Raymond E.; Steinetz, Bruce M.

2011-01-01

Inadequate turbomachine interface design can rapidly degrade system performance, yet provide great opportunity for improvements. Engineered coatings of seals and bearing interfaces are major issues in the operational life of power systems. Coatings, films, and combined use of both metals and ceramics play a major role in maintaining component life. Interface coatings, like lubricants, are sacrificial for the benefit of the component. Bearing and sealing surfaces are routinely protected by tribologically paired coatings such as silicon diamond like coatings (SiDLC) in combination with an oil lubricated wave bearing that prolongs bearing operational life. Likewise, of several methods used or researched for detecting interface failures, dopants within coatings show failures in functionally graded ceramic coatings. The Bozzolo-Ferrante-Smith (BFS) materials models and quantum mechanical tools, employed in interface design, are discussed.

Correlation of Predicted and Observed Optical Properties of Multilayer Thermal Control Coatings

NASA Technical Reports Server (NTRS)

Jaworske, Donald A.

1998-01-01

Thermal control coatings on spacecraft will be increasingly important, as spacecraft grow smaller and more compact. New thermal control coatings will be needed to meet the demanding requirements of next generation spacecraft. Computer programs are now available to design optical coatings and one such program was used to design several thermal control coatings consisting of alternating layers of WO3 and SiO2. The coatings were subsequently manufactured with electron beam evaporation and characterized with both optical and thermal techniques. Optical data were collected in both the visible region of the spectrum and the infrared. Predictions of solar absorptance and infrared emittance were successfully correlated to the observed thermal control properties. Functional performance of the coatings was verified in a bench top thermal vacuum chamber.

Silicon immersion gratings and their spectroscopic applications

NASA Astrophysics Data System (ADS)

Ge, Jian; Zhao, Bo; Powell, Scott; Fletcher, Adam; Wan, Xiaoke; Chang, Liang; Jakeman, Hali; Koukis, Dimitrios; Tanner, David B.; Ebbets, Dennis; Weinberg, Jonathan; Lipscy, Sarah; Nyquist, Rich; Bally, John

2012-09-01

Silicon immersion gratings (SIGs) offer several advantages over the commercial echelle gratings for high resolution infrared (IR) spectroscopy: 3.4 times the gain in dispersion or ~10 times the reduction in the instrument volume, a multiplex gain for a large continuous wavelength coverage and low cost. We present results from lab characterization of a large format SIG of astronomical observation quality. This SIG, with a 54.74 degree blaze angle (R1.4), 16.1 l/mm groove density, and 50x86 mm2 grating area, was developed for high resolution IR spectroscopy (R~70,000) in the near IR (1.1-2.5 μm). Its entrance surface was coated with a single layer of silicon nitride antireflection (AR) coating and its grating surface was coated with a thin layer of gold to increase its throughput at 1.1-2.5 μm. The lab measurements have shown that the SIG delivered a spectral resolution of R=114,000 at 1.55 μm with a lab testing spectrograph with a 20 mm diameter pupil. The measured peak grating efficiency is 72% at 1.55 μm, which is consistent with the measurements in the optical wavelengths from the grating surface at the air side. This SIG is being implemented in a new generation cryogenic IR spectrograph, called the Florida IR Silicon immersion grating spectrometer (FIRST), to offer broad-band high resolution IR spectroscopy with R=72,000 at 1.4-1.8 um under a typical seeing condition in a single exposure with a 2kx2k H2RG IR array at the robotically controlled Tennessee State University 2-meter Automatic Spectroscopic Telescope (AST) at Fairborn Observatory in Arizona. FIRST is designed to provide high precision Doppler measurements (~4 m/s) for the identification and characterization of extrasolar planets, especially rocky planets in habitable zones, orbiting low mass M dwarf stars. It will also be used for other high resolution IR spectroscopic observations of such as young stars, brown dwarfs, magnetic fields, star formation and interstellar mediums. An optimally designed SIG of the similar size can be used in the Silicon Immersion Grating Spectrometer (SIGS) to fill the need for high resolution spectroscopy at mid IR to far IR (~25-300 μm) for the NASA SOFIA airborne mission in the future.

Noble gas isotopes and halogens in volatile-rich inclusions in diamonds

NASA Technical Reports Server (NTRS)

Burgess, Raymond; Turner, Grenville

1994-01-01

Application of the (40)Ar-(39)Ar method and noble gas studies to diamonds has increased our understanding of their age relationships to the host kimberlite or lamproite, and of the source and composition of volatile-rich fluids in the upper mantle. The properties of diamond (inert, high mechanical strength and low gas diffusivities) means they are especially useful samples for studying gases trapped deep within the earth (less than 150 km) as they are unlikely to have undergone loss or exchange of entrapped material since formation. Volatile-rich fluids (H2O-CO2) are important agents for metasomatic processes in the upper mantle, and the noble gases and halogens preferentially partition into this phase leading to a strong geochemical coherence between these groups of elements. The abundances of the halogens in the major reservoirs of the Earth shows a marked progression from chlorine, concentrated in the oceans, through to iodine which, through its affinity to organic material, is concentrated mainly in sediments. Abundances in the upper mantle are low. This is particularly true for iodine which is of special interest in view of its potential significance as an indicator of sediment recycling and by way of its link to (129)Xe amomalies in the mantle through the low extinct isotope (129)I. Extensions of the (40)Ar-(39)Ar technique enable measurements of halogens and other elements (K, Ca, Ba, U) by production of noble gas isotopes from these species during neutron irradiation. Samples analyzed in this way include 15 coated stones from an unknown source in Zaire, 3 boarts from the Jwaneng and 1 boart from the Orapa kimberlites, both in Botswana.

Sedimentology and taphonomy of the upper Karoo-equivalent Mpandi Formation in the Tuli Basin of Zimbabwe, with a new 40Ar/ 39Ar age for the Tuli basalts

NASA Astrophysics Data System (ADS)

Rogers, Raymond R.; Rogers, Kristina Curry; Munyikwa, Darlington; Terry, Rebecca C.; Singer, Bradley S.

2004-10-01

Karoo-equivalent rocks in the Tuli Basin of Zimbabwe are described, with a focus on the dinosaur-bearing Mpandi Formation, which correlates with the Elliot Formation (Late Triassic-Early Jurassic) in the main Karoo Basin. Isolated exposures of the Mpandi Formation along the banks of the Limpopo River consist of red silty claystones and siltstones that preserve root traces, small carbonate nodules, and hematite-coated prosauropod bones. These fine-grained facies accumulated on an ancient semi-arid floodplain. Widespread exposures of quartz-rich sandstone and siltstone representing the upper Mpandi Formation crop out on Sentinel Ranch. These strata preserve carbonate concretions and silicified root casts, and exhibit cross-bedding indicative of deposition via traction currents, presumably in stream channels. Prosauropod fossils are also preserved in the Sentinel Ranch exposures, with one particularly noteworthy site characterized by a nearly complete and articulated Massospondylus individual. An unconformity caps the Mpandi Formation in the study area, and this stratigraphically significant surface rests on a laterally-continuous zone of pervasive silicification interpreted as a silcrete. Morphologic, petrographic, and geochemical data indicate that the Mpandi silcrete formed by intensive leaching near the ground surface during prolonged hiatus. Chert clasts eroded from the silcrete are intercalated at the base of the overlying Samkoto Formation (equivalent to the Clarens Formation in the main Karoo Basin), which in turn is overlain by the Tuli basalts. These basalts, which are part of the Karoo Igneous Province, yield a new 40Ar/ 39Ar plateau age of 186.3 ± 1.2 Ma.

The age of the Keystone thrust: laser-fusion 40Ar/39Ar dating of foreland basin deposits, southern Spring Mountains, Nevada

USGS Publications Warehouse

Fleck, R.J.; Carr, M.D.

1990-01-01

Nonmarine sedimentary and volcaniclastic foreland-basin deposits in the Spring Mountains are cut by the Contact and Keystone thrusts. These synorogenic deposits, informally designated the Lavinia Wash sequence by Carr (1980), previously were assigned a Late Jurassic to Early Cretaceous(?) age. New 40Ar.39Ar laser-fusion and incremental-heating studies of a tuff bed in the Lavinia Wash sequence support a best estimate age of 99.0 ?? 0.4 Ma, indicating that the Lavinia Wash sequence is actually late Early Cretaceous in age and establishing a maximum age for final emplacement of the Contact and Keystone thrust plates consistent with the remainder of the Mesozoic foreland thrust belt. -from Authors

Mouse allergen exposure and decreased risk of allergic rhinitis in school-aged children.

PubMed

Jacobs, Tammy S; Forno, Erick; Brehm, John M; Acosta-Pérez, Edna; Han, Yueh-Ying; Blatter, Joshua; Thorne, Peter; Metwali, Nervana; Colón-Semidey, Angel; Alvarez, María; Canino, Glorisa; Celedón, Juan C

2014-12-01

Little is known about exposure to mouse allergen (Mus m 1) and allergic rhinitis (AR). To evaluate the association between mouse allergen exposure and AR in children. We examined the relation between mouse allergen level in house dust and AR in 511 children aged 6 to 14 years in San Juan, Puerto Rico. Study participants were chosen from randomly selected households using a multistage probability sample design. The study protocol included questionnaires, allergy skin testing, and collection of blood and dust samples. AR was defined as current rhinitis symptoms and skin test reactivity to at least one allergen. In the multivariate analyses, mouse allergen level was associated with a 25% decreased odds of AR in participating children (95% confidence interval, 0.62-0.92). Although endotoxin and mouse allergen levels were significantly correlated (r = 0.184, P < .001), the observed inverse association between Mus m 1 and AR was not explained by levels of endotoxin or other markers of microbial or fungal exposure (peptidoglycan and glucan). Mouse allergen exposure is associated with decreased odds of AR in Puerto Rican school-aged children. Copyright © 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Design and Error Analysis of a Vehicular AR System with Auto-Harmonization.

PubMed

Foxlin, Eric; Calloway, Thomas; Zhang, Hongsheng

2015-12-01

This paper describes the design, development and testing of an AR system that was developed for aerospace and ground vehicles to meet stringent accuracy and robustness requirements. The system uses an optical see-through HMD, and thus requires extremely low latency, high tracking accuracy and precision alignment and calibration of all subsystems in order to avoid mis-registration and "swim". The paper focuses on the optical/inertial hybrid tracking system and describes novel solutions to the challenges with the optics, algorithms, synchronization, and alignment with the vehicle and HMD systems. Tracker accuracy is presented with simulation results to predict the registration accuracy. A car test is used to create a through-the-eyepiece video demonstrating well-registered augmentations of the road and nearby structures while driving. Finally, a detailed covariance analysis of AR registration error is derived.

Thermal Conductivity and Sintering Behavior of Advanced Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.

2002-01-01

Advanced thermal barrier coatings, having significantly reduced long-term thermal conductivities, are being developed using an approach that emphasizes real-time monitoring of thermal conductivity under conditions that are engine-like in terms of temperatures and heat fluxes. This is in contrast to the traditional approach where coatings are initially optimized in terms of furnace and burner rig durability with subsequent measurement in the as-processed or furnace-sintered condition. The present work establishes a laser high-heat-flux test as the basis for evaluating advanced plasma-sprayed and physical vapor-deposited thermal barrier coatings under the NASA Ultra Efficient Engine Technology (UEET) Program. The candidate coating materials for this program are novel thermal barrier coatings that are found to have significantly reduced thermal conductivities due to an oxide-defect-cluster design. Critical issues for designing advanced low conductivity coatings with improved coating durability are also discussed.

Strain isolated ceramic coatings

NASA Technical Reports Server (NTRS)

Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

1985-01-01

Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

Development of Advanced Low Conductivity Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dong-Ming; Miller, Robert A.

2004-01-01

Advanced multi-component, low conductivity oxide thermal barrier coatings have been developed using an approach that emphasizes real-time monitoring of thermal conductivity under conditions that are engine-like in terms of temperatures and heat fluxes. This is in contrast to the traditional approach where coatings are initially optimized in terms of furnace and burner rig durability with subsequent measurement in the as-processed or furnace-sintered condition. The present work establishes a laser high-heat-flux test as the basis for evaluating advanced plasma-sprayed and electron beam-physical vapor deposited (EB-PVD) thermal barrier coatings under the NASA Ultra-Efficient Engine Technology (UEET) Program. The candidate coating materials for this program are novel thermal barrier coatings that are found to have significantly reduced thermal conductivities and improved thermal stability due to an oxide-defect-cluster design. Critical issues for designing advanced low conductivity coatings with improved coating durability are also discussed.

Development and Life Prediction of Erosion Resistant Turbine Low Conductivity Thermal Barrier Coatings

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.; Kuczmarski, Maria A.

2010-01-01

Future rotorcraft propulsion systems are required to operate under highly-loaded conditions and in harsh sand erosion environments, thereby imposing significant material design and durability issues. The incorporation of advanced thermal barrier coatings (TBC) in high pressure turbine systems enables engine designs with higher inlet temperatures, thus improving the engine efficiency, power density and reliability. The impact and erosion resistance of turbine thermal barrier coating systems are crucial to the turbine coating technology application, because a robust turbine blade TBC system is a prerequisite for fully utilizing the potential coating technology benefit in the rotorcraft propulsion. This paper describes the turbine blade TBC development in addressing the coating impact and erosion resistance. Advanced thermal barrier coating systems with improved performance have also been validated in laboratory simulated engine erosion and/or thermal gradient environments. A preliminary life prediction modeling approach to emphasize the turbine blade coating erosion is also presented.

Laboratory experiments on carbonaceous material as a source for the red rectangle visual emissions

NASA Technical Reports Server (NTRS)

Wdowiak, Thomas J.; Donn, Bertram; Nuth, Joseph A.; Chappelle, Emmett; Moore, Marla

1989-01-01

The authors subjected mixtures of CO, Ar, N2, H2O, and CH4 with 42 percent and 8 percent argon to an electrical discharge, froze out the reaction products at T about 20 K, and subsequently warmed the sample to room temperature. This resulted in a stable residue having broad-band fluorescence. It is suggested tht interstellar grains in the Red Rectangle/HD 44179 are coated with a residue of generally similar composition that is responsible for the broad emission feature in the 5400-7500 A spectral region.

Thermodynamic Analysis and Growth of Zirconium Carbide by Chemical Vapor Deposition

NASA Astrophysics Data System (ADS)

Wei, Sun; Hua, Hao Zheng; Xiang, Xiong

Equilibrium calculations were used to optimize conditions for the chemical vapor deposition of zirconium carbide from zirconium halide + CxHy+H2+Ar system. The results show the CVD-ZrC phase diagram is divided into ZrC+C, ZrC and ZrC+Zr zones by C, Zr generating lines. For the same mole of ZrCl4 reactant, it needs higher concentration of CH4 to generate single ZrC phase than that of C3H6. Using these calculations as a guide, single-phase cubic zirconium carbide coatings were deposited onto graphite substrate.

Thermal and vibration testing of ruggedized IR-transmitting fiber cables

NASA Astrophysics Data System (ADS)

Busse, Lynda; Kung, Fred; Florea, Catalin; Shaw, Brandon; Aggarwal, Ishwar; Sanghera, Jas

2013-05-01

We present successful results obtained for thermal/ vibration testing of ruggedized, IR-transmitting chalcogenide glass fiber cables using a government facility with state-of-the-art equipment capable of MIL-SPEC environmental testing. We will also present results of a direct imprinting process to create novel "moth eye" patterned surfaces on the IR fiber cable ends that significantly reduces endface reflection losses from 17% to less than 3%. The cables with these imprinted "moth eye" ends transmit much higher IR laser power without damage than was obtained for previous cables with traditional AR coatings.

High color fidelity thin film multilayer systems for head-up display use

NASA Astrophysics Data System (ADS)

Tsou, Yi-Jen D.; Ho, Fang C.

1996-09-01

Head-up display is gaining increasing access in automotive vehicles for indication and position/navigation purposes. An optical combiner, which allows the driver to receive image information from outside and inside of the automobile, is the essential part of this display device. Two multilayer thin film combiner coating systems with distinctive polarization selectivity and broad band spectral neutrality are discussed. One of the coating systems was designed to be located at the lower portion of the windshield. The coating reduced the exterior glare by approximately 45% and provided about 70% average see-through transmittance in addition to the interior information display. The other coating system was designed to be integrated with the sunshield located at the upper portion of the windshield. The coating reflected the interior information display while reducing direct sunlight penetration to 25%. Color fidelity for both interior and exterior images were maintained in both systems. This facilitated the display of full-color maps. Both coating systems were absorptionless and environmentally durable. Designs, fabrication, and performance of these coating systems are addressed.

Broadband angle-independent antireflection coatings on nanostructured light trapping solar cells

NASA Astrophysics Data System (ADS)

Vázquez-Guardado, Abraham; Boroumand, Javaneh; Franklin, Daniel; Chanda, Debashis

2018-03-01

Backscattering from nanostructured surfaces greatly diminishes the efficacy of light trapping solar cells. While the analytical design of broadband, angle-independent antireflection coatings on nanostructured surfaces proved inefficient, numerical optimization proves a viable alternative. Here, we numerically design and experimentally verify the performance of single and bilayer antireflection coatings on a 2D hexagonal diffractive light trapping pattern on crystalline silicon substrates. Three well-known antireflection coatings, aluminum oxide, silicon nitride, and silicon oxide, which also double as high-quality surface passivation materials, are studied in the 400-1000 nm band. By varying thickness and conformity, the optimal parameters that minimize the broadband total reflectance (specular and scattering) from the nanostructured surface are obtained. The design results in a single-layer antireflection coating with normal-angle wavelength-integrated reflectance below 4% and a bilayer antireflection coating demonstrating reflection down to 1.5%. We show experimentally an angle-averaged reflectance of ˜5.2 % up to 60° incident angle from the optimized bilayer antireflection-coated nanostructured surface, paving the path toward practical implementation of the light trapping solar cells.

High reflectance coatings for space applications in the EUV

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A. M.; Gum, Jeffrey S.; Osantowski, John F.; Fleetwood, Charles M.

1993-01-01

Advances in optical coating and materials technology have made possible the development of instruments with substantially improved efficiency and made possible to consider more complex optical designs in the EUV. The importance of recent developments in chemical vapor deposited silicon carbide (CVD-SiC), SiC films and multilayer coatings is discussed in the context of EUV instrumentation design. The EUV performance of these coatings as well as some strengths and problem areas for their use in space will be addressed.

Design and Performance of Property Gradient Ternary Nitride Coating Based on Process Control.

PubMed

Yan, Pei; Chen, Kaijie; Wang, Yubin; Zhou, Han; Peng, Zeyu; Jiao, Li; Wang, Xibin

2018-05-09

Surface coating is an effective approach to improve cutting tool performance, and multiple or gradient coating structures have become a common development strategy. However, composition mutations at the interfaces decrease the performance of multi-layered coatings. The key mitigation technique has been to reduce the interface effect at the boundaries. This study proposes a structure design method for property-component gradient coatings based on process control. The method produces coatings with high internal cohesion and high external hardness, which could reduce the composition and performance mutations at the interface. A ZrTiN property gradient ternary nitride coating was deposited on cemented carbide by multi-arc ion plating with separated Ti and Zr targets. The mechanical properties, friction behaviors, and cutting performances were systematically investigated, compared with a single-layer coating. The results indicated that the gradient coating had better friction and wear performance with lower wear rate and higher resistance to peeling off during sliding friction. The gradient coating had better wear and damage resistance in cutting processes, with lower machined surface roughness Ra. Gradient-structured coatings could effectively inhibit micro crack initiation and growth under alternating force and temperature load. This method could be extended to similar ternary nitride coatings.

Identification and Characterization of ART-27, a Novel Coactivator for the Androgen Receptor N Terminus

PubMed Central

Markus, Steven M.; Taneja, Samir S.; Logan, Susan K.; Li, Wenhui; Ha, Susan; Hittelman, Adam B.; Rogatsky, Inez; Garabedian, Michael J.

2002-01-01

The androgen receptor (AR) is a ligand-regulated transcription factor that stimulates cell growth and differentiation in androgen-responsive tissues. The AR N terminus contains two activation functions (AF-1a and AF-1b) that are necessary for maximal transcriptional enhancement by the receptor; however, the mechanisms and components regulating AR transcriptional activation are not fully understood. We sought to identify novel factors that interact with the AR N terminus from an androgen-stimulated human prostate cancer cell library using a yeast two-hybrid approach designed to identify proteins that interact with transcriptional activation domains. A 157-amino acid protein termed ART-27 was cloned and shown to interact predominantly with the AR153–336, containing AF-1a and a part of AF-1b, localize to the nucleus and increase the transcriptional activity of AR when overexpressed in cultured mammalian cells. ART-27 also enhanced the transcriptional activation by AR153–336 fused to the LexA DNA-binding domain but not other AR N-terminal subdomains, suggesting that ART-27 exerts its effect via an interaction with a defined region of the AR N terminus. ART-27 interacts with AR in nuclear extracts from LNCaP cells in a ligand-independent manner. Interestingly, velocity gradient sedimentation of HeLa nuclear extracts suggests that native ART-27 is part of a multiprotein complex. ART-27 is expressed in a variety of human tissues, including sites of androgen action such as prostate and skeletal muscle, and is conserved throughout evolution. Thus, ART-27 is a novel cofactor that interacts with the AR N terminus and plays a role in facilitating receptor-induced transcriptional activation. PMID:11854421

Beta-3 adrenergic agonists reduce pulmonary vascular resistance and improve right ventricular performance in a porcine model of chronic pulmonary hypertension.

PubMed

García-Álvarez, Ana; Pereda, Daniel; García-Lunar, Inés; Sanz-Rosa, David; Fernández-Jiménez, Rodrigo; García-Prieto, Jaime; Nuño-Ayala, Mario; Sierra, Federico; Santiago, Evelyn; Sandoval, Elena; Campelos, Paula; Agüero, Jaume; Pizarro, Gonzalo; Peinado, Víctor I; Fernández-Friera, Leticia; García-Ruiz, José M; Barberá, Joan A; Castellá, Manuel; Sabaté, Manel; Fuster, Valentín; Ibañez, Borja

2016-07-01

Beta-3 adrenergic receptor (β3AR) agonists have been shown to produce vasodilation and prevention of ventricular remodeling in different conditions. Given that these biological functions are critical in pulmonary hypertension (PH), we aimed to demonstrate a beneficial effect of β3AR agonists in PH. An experimental study in pigs (n = 34) with chronic PH created by pulmonary vein banding was designed to evaluate the acute hemodynamic effect and the long-term effect of β3AR agonists on hemodynamics, vascular remodeling and RV performance in chronic PH. Ex vivo human experiments were performed to explore the expression of β3AR mRNA and the vasodilator response of β3AR agonists in pulmonary arteries. Single intravenous administration of the β3AR agonist BRL37344 produced a significant acute reduction in PVR, and two-weeks treatment with two different β3AR selective agonists, intravenous BRL37344 or oral mirabegron, resulted in a significant reduction in PVR (median of -2.0 Wood units/m(2) for BRL37344 vs. +1.5 for vehicle, p = 0.04; and -1.8 Wood units/m(2) for mirabegron vs. +1.6 for vehicle, p = 0.002) associated with a significant improvement in magnetic resonance-measured RV performance. Histological markers of pulmonary vascular proliferation (p27 and Ki67) were significantly attenuated in β3AR agonists-treated pigs. β3AR was expressed in human pulmonary arteries and β3AR agonists produced vasodilatation. β3AR agonists produced a significant reduction in PVR and improved RV performance in experimental PH, emerging as a potential novel approach for treating patients with chronic PH.

Identification and characterization of ART-27, a novel coactivator for the androgen receptor N terminus.

PubMed

Markus, Steven M; Taneja, Samir S; Logan, Susan K; Li, Wenhui; Ha, Susan; Hittelman, Adam B; Rogatsky, Inez; Garabedian, Michael J

2002-02-01

The androgen receptor (AR) is a ligand-regulated transcription factor that stimulates cell growth and differentiation in androgen-responsive tissues. The AR N terminus contains two activation functions (AF-1a and AF-1b) that are necessary for maximal transcriptional enhancement by the receptor; however, the mechanisms and components regulating AR transcriptional activation are not fully understood. We sought to identify novel factors that interact with the AR N terminus from an androgen-stimulated human prostate cancer cell library using a yeast two-hybrid approach designed to identify proteins that interact with transcriptional activation domains. A 157-amino acid protein termed ART-27 was cloned and shown to interact predominantly with the AR(153-336), containing AF-1a and a part of AF-1b, localize to the nucleus and increase the transcriptional activity of AR when overexpressed in cultured mammalian cells. ART-27 also enhanced the transcriptional activation by AR(153-336) fused to the LexA DNA-binding domain but not other AR N-terminal subdomains, suggesting that ART-27 exerts its effect via an interaction with a defined region of the AR N terminus. ART-27 interacts with AR in nuclear extracts from LNCaP cells in a ligand-independent manner. Interestingly, velocity gradient sedimentation of HeLa nuclear extracts suggests that native ART-27 is part of a multiprotein complex. ART-27 is expressed in a variety of human tissues, including sites of androgen action such as prostate and skeletal muscle, and is conserved throughout evolution. Thus, ART-27 is a novel cofactor that interacts with the AR N terminus and plays a role in facilitating receptor-induced transcriptional activation.

Thermal and Environmental Barrier Coating Development for Advanced Propulsion Engine Systems

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Miller, Robert A.; Fox, Dennis S.

2008-01-01

Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. Advanced TEBCs that have significantly lower thermal conductivity, better thermal stability and higher toughness than current coatings will be beneficial for future low emission and high performance propulsion engine systems. In this paper, ceramic coating design and testing considerations will be described for turbine engine high temperature and high-heat-flux applications. Thermal barrier coatings for metallic turbine airfoils and thermal/environmental barrier coatings for SiC/SiC ceramic matrix composite (CMC) components for future supersonic aircraft propulsion engines will be emphasized. Further coating capability and durability improvements for the engine hot-section component applications can be expected by utilizing advanced modeling and design tools.

Identification of an AR Mutation-Negative Class of Androgen Insensitivity by Determining Endogenous AR Activity

PubMed Central

Ukat, M.; Schweikert, H. U.; Hiort, O.; Werner, R.; Drop, S. L. S.; Cools, M.; Hughes, I. A.; Audi, L.; Ahmed, S. F.; Demiri, J.; Rodens, P.; Worch, L.; Wehner, G.; Kulle, A. E.; Dunstheimer, D.; Müller-Roßberg, E.; Reinehr, T.; Hadidi, A. T.; Eckstein, A. K.; van der Horst, C.; Seif, C.; Siebert, R.; Ammerpohl, O.; Holterhus, P.-M.

2016-01-01

Context: Only approximately 85% of patients with a clinical diagnosis complete androgen insensitivity syndrome and less than 30% with partial androgen insensitivity syndrome can be explained by inactivating mutations in the androgen receptor (AR) gene. Objective: The objective of the study was to clarify this discrepancy by in vitro determination of AR transcriptional activity in individuals with disorders of sex development (DSD) and male controls. Design: Quantification of DHT-dependent transcriptional induction of the AR target gene apolipoprotein D (APOD) in cultured genital fibroblasts (GFs) (APOD assay) and next-generation sequencing of the complete coding and noncoding AR locus. Setting: The study was conducted at a university hospital endocrine research laboratory. Patients: GFs from 169 individuals were studied encompassing control males (n = 68), molecular defined DSD other than androgen insensitivity syndrome (AIS; n = 18), AR mutation-positive AIS (n = 37), and previously undiagnosed DSD including patients with a clinical suspicion of AIS (n = 46). Intervention(s): There were no interventions. Main Outcome Measure(s): DHT-dependent APOD expression in cultured GF and AR mutation status in 169 individuals was measured. Results: The APOD assay clearly separated control individuals (healthy males and molecular defined DSD patients other than AIS) from genetically proven AIS (cutoff < 2.3-fold APOD-induction; 100% sensitivity, 93.3% specificity, P < .0001). Of 46 DSD individuals with no AR mutation, 17 (37%) fell below the cutoff, indicating disrupted androgen signaling. Conclusions: AR mutation-positive AIS can be reliably identified by the APOD assay. Its combination with next-generation sequencing of the AR locus uncovered an AR mutation-negative, new class of androgen resistance, which we propose to name AIS type II. Our data support the existence of cellular components outside the AR affecting androgen signaling during sexual differentiation with high clinical relevance. PMID:27583472

Accelerated Recovery Within Standardized Recovery Pathways After Esophagectomy: A Prospective Cohort Study Assessing the Effects of Early Discharge on Outcomes, Readmissions, Patient Satisfaction, and Costs.

PubMed

Schmidt, Henner M; El Lakis, Mustapha A; Markar, Sheraz R; Hubka, Michal; Low, Donald E

2016-09-01

After esophagectomy, some patients exceed targeted discharge goal within enhanced recovery after surgery programs. This study reviews the demographics, outcomes, cost, readmission rates, and patient satisfaction for the accelerated recovery (AR) group. Between 2010 and 2013, 137 consecutive esophagectomy patients were compared according to the length of hospital stay: AR 5 to 6 days, targeted recovery (TR) 7 to 8 days, and delayed recovery (DR) 9 days or more. The AR patients increased from 3% to 46% during the study period. The AR patients were younger, but all groups were comparable regarding comorbidities (Charlson, American Society of Anesthesiologists, and Eastern Cooperative Oncology Group score), cancer stage, and treatment approach. The AR patients were more likely to have neoadjuvant therapy, shorter operations, and less blood loss. The DR patients were more likely to have complications (40% AR versus 45% TR versus 90% DR, p < 0.001). Inhospital and 90-day mortality was 1.5%. All AR patients were discharged home (100% AR versus 87% TR versus 63% DR, p < 0.001), and 30-day readmission rates were comparable between groups (14% AR versus 19% TR versus 5% DR, p = 0.122). Overall mean costs ($38,385 AR versus $41,607 TR versus $61,199 DR, p < 0.001) as well as readmission costs ($7,470 AR versus $27,695 TR versus $33,398 DR, p = 0.202) were lower in the AR group. Patient satisfaction scores were comparable between groups. Accelerated recovery is achievable in a significant proportion of patients undergoing esophagectomy. Accelerated recovery is associated with decreased treatment costs but does not lead to increased readmissions or decreased patient satisfaction. Enhanced recovery after surgery programs should be designed to accommodate patients appropriate for AR. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Dissipated energy as a design parameter of coated conductors for their use in resistive fault current limiters

NASA Astrophysics Data System (ADS)

Schacherer, C.; Kudymow, A.; Noe, M.

2008-02-01

Coated conductors are suitable for many power applications like motors, magnets and superconducting fault current limiters (SCFCLs). For their use in resistive SCFCLs main requirements are quench stability and resistance development above Tc. Several coated conductors are available with different kinds of stabilization like thickness or material of cap-layer and additional stabilization. The stabilization can vary and has a great influence on the quench stability and quench behaviour of a coated conductor. Thus, for the dimensioning of a superconducting current limiting element there is a need of reliable and universal design parameters. This paper presents experimental quench test results on several coated conductor types with different stabilization and geometry. The test results show that the dissipated energy during a quench is a very useful parameter for the SCFCL design.

Action Researchers Encountering Ethical Review: A Literature Synthesis on Challenges and Strategies

ERIC Educational Resources Information Center

Fouché, Christa B.; Chubb, Laura A.

2017-01-01

Action research (AR) comprises a diverse family of methodologies. Common amongst most types of AR are both an emergent design--leading to action or change--and participation or community involvement. While this type of research has expanded considerably since the early 2000s, the criteria used for ethical review have apparently been slow to adapt…

Impacts of Integrating the Repertory Grid into an Augmented Reality-Based Learning Design on Students' Learning Achievements, Cognitive Load and Degree of Satisfaction

ERIC Educational Resources Information Center

Wu, Po-Han; Hwang, Gwo-Jen; Yang, Mei-Ling; Chen, Chih-Hung

2018-01-01

Augmented reality (AR) offers potential advantages for intensifying environmental context awareness and augmenting students' experiences in real-world environments by dynamically overlapping digital materials with a real-world environment. However, some challenges to AR learning environments have been described, such as participants' cognitive…

Visual Environment for Designing Interactive Learning Scenarios with Augmented Reality

ERIC Educational Resources Information Center

Mota, José Miguel; Ruiz-Rube, Iván; Dodero, Juan Manuel; Figueiredo, Mauro

2016-01-01

Augmented Reality (AR) technology allows the inclusion of virtual elements on a vision of actual physical environment for the creation of a mixed reality in real time. This kind of technology can be used in educational settings. However, the current AR authoring tools present several drawbacks, such as, the lack of a mechanism for tracking the…

Supporting Situated Learning Based on QR Codes with Etiquetar App: A Pilot Study

ERIC Educational Resources Information Center

Camacho, Miguel Olmedo; Pérez-Sanagustín, Mar; Alario-Hoyos, Carlos; Soldani, Xavier; Kloos, Carlos Delgado; Sayago, Sergio

2014-01-01

EtiquetAR is an authoring tool for supporting the design and enactment of situated learning experiences based on QR tags. Practitioners use etiquetAR for creating, managing and personalizing collections of QR codes with special properties: (1) codes can have more than one link pointing at different multimedia resources, (2) codes can be updated…

Androgen receptor: structure, role in prostate cancer and drug discovery

PubMed Central

Tan, MH Eileen; Li, Jun; Xu, H Eric; Melcher, Karsten; Yong, Eu-leong

2015-01-01

Androgens and androgen receptors (AR) play a pivotal role in expression of the male phenotype. Several diseases, such as androgen insensitivity syndrome (AIS) and prostate cancer, are associated with alterations in AR functions. Indeed, androgen blockade by drugs that prevent the production of androgens and/or block the action of the AR inhibits prostate cancer growth. However, resistance to these drugs often occurs after 2–3 years as the patients develop castration-resistant prostate cancer (CRPC). In CRPC, a functional AR remains a key regulator. Early studies focused on the functional domains of the AR and its crucial role in the pathology. The elucidation of the structures of the AR DNA binding domain (DBD) and ligand binding domain (LBD) provides a new framework for understanding the functions of this receptor and leads to the development of rational drug design for the treatment of prostate cancer. An overview of androgen receptor structure and activity, its actions in prostate cancer, and how structural information and high-throughput screening have been or can be used for drug discovery are provided herein. PMID:24909511

Clinical vision characteristics of the congenital achromatopsias. II. Color vision.

PubMed

Haegerstrom-Portnoy, G; Schneck, M E; Verdon, W A; Hewlett, S E

1996-07-01

Twelve X-linked (XL) achromats and 43 autosomal recessive (AR) achromats were tested using the Farnsworth D-15, Nagel anomaloscope, Sloan achromatopsia test, and Berson test using standard procedures. All of the tests identify achromatopsia, but very few differentially diagnose the various types. AR achromats were subclassified as complete (rods only) or incomplete (residual cone function present) by additional psychophysical testing. Complete and incomplete ARs do not perform differently on any clinical color vision measure, indicating that (1) rods predominantly mediate vision in both groups and (2) these tests are not useful for distinguishing between the groups. Both groups show considerable interindividual variation on all measures. Only one of the measures, the Berson test, designed to distinguish XLs from ARs, does so reliably. XLs and ARs do not differ significantly on the Nagel anomaloscope or most of the Sloan plates. The confusion angles of the D-15 do differ for the two groups, but the variability in each group makes the measure unreliable for classifying individuals. The Berson test is recommended to distinguish the XL from AR achromats.

A Multifunctional Smart Coating for Autonomous Corrosion Control

NASA Technical Reports Server (NTRS)

Calle, Luz Marina; Buhrow, Jerry W.; Jolley, Scott T.

2012-01-01

Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on micro-encapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy. This

A Multifunctional Coating for Autonomous Corrosion Control

NASA Technical Reports Server (NTRS)

Calle, Luz M.; Hintze, Paul E.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.

2010-01-01

Corrosion is a destructive process that often causes failure in metallic components and structures. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where they are needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into the microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy.

Depth profiles of oxygen precipitates in nitride-coated silicon wafers subjected to rapid thermal annealing

NASA Astrophysics Data System (ADS)

Voronkov, V. V.; Falster, R.; Kim, TaeHyeong; Park, SoonSung; Torack, T.

2013-07-01

Silicon wafers, coated with a silicon nitride layer and subjected to high temperature Rapid Thermal Annealing (RTA) in Ar, show—upon a subsequent two-step precipitation anneal cycle (such as 800 °C + 1000 °C)—peculiar depth profiles of oxygen precipitate densities. Some profiles are sharply peaked near the wafer surface, sometimes with a zero bulk density. Other profiles are uniform in depth. The maximum density is always the same. These profiles are well reproduced by simulations assuming that precipitation starts from a uniformly distributed small oxide plates originated from RTA step and composed of oxygen atoms and vacancies ("VO2 plates"). During the first step of the precipitation anneal, an oxide layer propagates around this core plate by a process of oxygen attachment, meaning that an oxygen-only ring-shaped plate emerges around the original plate. These rings, depending on their size, then either dissolve or grow during the second part of the anneal leading to a rich variety of density profiles.

Polymeric media comprising polybenzimidazoles N-substituted with organic-inorganic hybrid moiety

DOEpatents

Klaehn, John R [Idaho Falls, ID; Peterson, Eric S [Idaho Falls, ID; Wertsching, Alan K [Idaho Falls, ID; Orme, Christopher J [Shelley, ID; Luther, Thomas A [Idaho Falls, ID; Jones, Michael G [Pocatello, ID

2009-12-15

A PBI compound includes imidazole nitrogens at least a portion of which are substituted with an organic-inorganic hybrid moiety may be included in a separator medium. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2-- where R is selected from among methyl, phenyl, vinyl, and allyl. The separatory medium may exhibit an H.sub.2, Ar, N.sub.2, O.sub.2, CH.sub.3, or CO.sub.2 gas permeability greater than the gas permeability of a comparable separatory medium comprising the PBI compound without substitution. The separatory medium may further include an electronically conductive medium and/or ionically conductive medium. The separatory medium may be used as a membrane (semi-permeable, permeable, and non-permeable), a barrier, an ion exhcange media, a filter, a gas chromatography coating (such as stationary phase coating in affinity chromatography), etc.

Molecular Docking and Prediction of Pharmacokinetic Properties of Dual Mechanism Drugs that Block MAO-B and Adenosine A2A Receptors for the Treatment of Parkinson's Disease

PubMed Central

Azam, Faizul; Madi, Arwa M.; Ali, Hamed I.

2012-01-01

Monoamine oxidase B (MAO-B) inhibitory potential of adenosine A2A receptor (AA2AR) antagonists has raised the possibility of designing dual-target–directed drugs that may provide enhanced symptomatic relief and that may also slow the progression of Parkinson's disease (PD) by protecting against further neurodegeneration. To explain the dual inhibition of MAO-B and AA2AR at the molecular level, molecular docking technique was employed. Lamarckian genetic algorithm methodology was used for flexible ligand docking studies. A good correlation (R2= 0.524 and 0.627 for MAO-B and AA2AR, respectively) was established between docking predicted and experimental Ki values, which confirms that the molecular docking approach is reliable to study the mechanism of dual interaction of caffeinyl analogs with MAO-B and AA2AR. Parameters for Lipinski's “Rule-of-Five” were also calculated to estimate the pharmacokinetic properties of dual-target–directed drugs where both MAO-B inhibition and AA2AR antagonism exhibited a positive correlation with calculated LogP having a correlation coefficient R2 of 0.535 and 0.607, respectively. These results provide some beneficial clues in structural modification for designing new inhibitors as dual-target–directed drugs with desired pharmacokinetic properties for the treatment of PD. PMID:23112538

Analysis of Mental Workload in Online Shopping: Are Augmented and Virtual Reality Consistent?

PubMed

Zhao, Xiaojun; Shi, Changxiu; You, Xuqun; Zong, Chenming

2017-01-01

A market research company (Nielsen) reported that consumers in the Asia-Pacific region have become the most active group in online shopping. Focusing on augmented reality (AR), which is one of three major techniques used to change the method of shopping in the future, this study used a mixed design to discuss the influences of the method of online shopping, user gender, cognitive style, product value, and sensory channel on mental workload in virtual reality (VR) and AR situations. The results showed that males' mental workloads were significantly higher than females'. For males, high-value products' mental workload was significantly higher than that of low-value products. In the VR situation, the visual mental workload of field-independent and field-dependent consumers showed a significant difference, but the difference was reduced under audio-visual conditions. In the AR situation, the visual mental workload of field-independent and field-dependent consumers showed a significant difference, but the difference increased under audio-visual conditions. This study provided a psychological study of online shopping with AR and VR technology with applications in the future. Based on the perspective of embodied cognition, AR online shopping may be potential focus of research and market application. For the future design of online shopping platforms and the updating of user experience, this study provides a reference.

Analysis of Mental Workload in Online Shopping: Are Augmented and Virtual Reality Consistent?

PubMed Central

Zhao, Xiaojun; Shi, Changxiu; You, Xuqun; Zong, Chenming

2017-01-01

A market research company (Nielsen) reported that consumers in the Asia-Pacific region have become the most active group in online shopping. Focusing on augmented reality (AR), which is one of three major techniques used to change the method of shopping in the future, this study used a mixed design to discuss the influences of the method of online shopping, user gender, cognitive style, product value, and sensory channel on mental workload in virtual reality (VR) and AR situations. The results showed that males’ mental workloads were significantly higher than females’. For males, high-value products’ mental workload was significantly higher than that of low-value products. In the VR situation, the visual mental workload of field-independent and field-dependent consumers showed a significant difference, but the difference was reduced under audio–visual conditions. In the AR situation, the visual mental workload of field-independent and field-dependent consumers showed a significant difference, but the difference increased under audio–visual conditions. This study provided a psychological study of online shopping with AR and VR technology with applications in the future. Based on the perspective of embodied cognition, AR online shopping may be potential focus of research and market application. For the future design of online shopping platforms and the updating of user experience, this study provides a reference. PMID:28184207

Acetate oxidation by syntrophic association between Geobacter sulfurreducens and a hydrogen-utilizing exoelectrogen

PubMed Central

Kimura, Zen-ichiro; Okabe, Satoshi

2013-01-01

Anodic microbial communities in acetate-fed microbial fuel cells (MFCs) were analyzed using stable-isotope probing of 16S rRNA genes followed by denaturing gradient gel electrophoresis. The results revealed that Geobacter sulfurreducens and Hydrogenophaga sp. predominated in the anodic biofilm. Although the predominance of Geobacter sp. as acetoclastic exoelectrogens in acetate-fed MFC systems has been often reported, the ecophysiological role of Hydrogenophaga sp. is unknown. Therefore, we isolated and characterized a bacterium closely related to Hydrogenophaga sp. (designated strain AR20). The newly isolated strain AR20 could use molecular hydrogen (H2), but not acetate, with carbon electrode as the electron acceptor, indicating that the strain AR20 was a hydrogenotrophic exoelectrogen. This evidence raises a hypothesis that acetate was oxidized by G. sulfurreducens in syntrophic cooperation with the strain AR20 as a hydrogen-consuming partner in the acetate-fed MFC. To prove this hypothesis, G. sulfurreducens strain PCA was cocultivated with the strain AR20 in the acetate-fed MFC without any dissolved electron acceptors. In the coculture MFC of G. sulfurreducens and strain AR20, current generation and acetate degradation were the highest, and the growth of strain AR20 was observed. No current generation, acetate degradation and cell growth occurred in the strain AR20 pure culture MFC. These results show for the first time that G. sulfurreducens can oxidize acetate in syntrophic cooperation with the isolated Hydrogenophaga sp. strain AR20, with electrode as the electron acceptor. PMID:23486252

Acetate oxidation by syntrophic association between Geobacter sulfurreducens and a hydrogen-utilizing exoelectrogen.

PubMed

Kimura, Zen-ichiro; Okabe, Satoshi

2013-08-01

Anodic microbial communities in acetate-fed microbial fuel cells (MFCs) were analyzed using stable-isotope probing of 16S rRNA genes followed by denaturing gradient gel electrophoresis. The results revealed that Geobacter sulfurreducens and Hydrogenophaga sp. predominated in the anodic biofilm. Although the predominance of Geobacter sp. as acetoclastic exoelectrogens in acetate-fed MFC systems has been often reported, the ecophysiological role of Hydrogenophaga sp. is unknown. Therefore, we isolated and characterized a bacterium closely related to Hydrogenophaga sp. (designated strain AR20). The newly isolated strain AR20 could use molecular hydrogen (H2), but not acetate, with carbon electrode as the electron acceptor, indicating that the strain AR20 was a hydrogenotrophic exoelectrogen. This evidence raises a hypothesis that acetate was oxidized by G. sulfurreducens in syntrophic cooperation with the strain AR20 as a hydrogen-consuming partner in the acetate-fed MFC. To prove this hypothesis, G. sulfurreducens strain PCA was cocultivated with the strain AR20 in the acetate-fed MFC without any dissolved electron acceptors. In the coculture MFC of G. sulfurreducens and strain AR20, current generation and acetate degradation were the highest, and the growth of strain AR20 was observed. No current generation, acetate degradation and cell growth occurred in the strain AR20 pure culture MFC. These results show for the first time that G. sulfurreducens can oxidize acetate in syntrophic cooperation with the isolated Hydrogenophaga sp. strain AR20, with electrode as the electron acceptor.

Double dielectric barrier (DBD) plasma-assisted deposition of chemical stabilized nanoparticles on polyamide 6,6 and polyester fabrics

NASA Astrophysics Data System (ADS)

Ribeiro, A. I.; Modic, M.; Cvelbar, U.; Dinescu, G.; Mitu, B.; Nikiforov, A.; Leys, C.; Kuchakova, I.; Vanneste, M.; Heyse, P.; De Vrieze, M.; Carneiro, N.; Souto, A. P.; Zille, A.

2017-10-01

The development of new multifunctional textiles containing nanoparticles (NPs) has a special interest in several applications for pharmaceutical and medical products. Cu, Zn and Ag are the most promising antimicrobial NPs, exhibiting strong antibacterial activities. However, most of antimicrobial textiles coated with NPs are not able to perform a controlled release of NPs because of the high degree of aggregation. The aim of this study is to assess the effect of NPs stabilizers such as citrate, alginate and polyvinyl alcohol (PVA) in Cu, Zn and Ag NPs dispersions. The obtained dispersions were used to develop a new class of antibacterial NPs coatings onto polyamide 6,6 (PA66) and polyester fabrics (PES) by Double Dielectric Barrier (DBD) plasma discharge. Dynamic light scattering (DLS) was used to evaluate the best dispersing agent in terms of size, polydispersity index and zeta potential. Coating efficiency was evaluated by SEM, XPS and FTIR. The washing fastness of the coatings developed was also tested. The results show that the best dispersions were obtained using 2.5% of citrate for ZnO, 5% Alginate for Cu and 2.5% alginate for Ag NPs. SEM, XPS and FTIR analysis shows that DBD is an efficient deposition technique only for Ag and Cu NPs and that better perform in PA66 than PES fabric. The DBD deposition in air display similar results in term of NPS deposition of usually more efficient plasma jets using carrier gas such as N2 and Ar.

Laser Damage in Thin Film Optical Coatings

DTIC Science & Technology

1992-07-01

10) using E- beam evaporation and laser tests performed to determine the effect of conditioning laser spot size and coating design on improvement in...1.06 pm) consisting of a 15 layer 3 quarter-wave design (HFO2/SiO 2 and ZrO2/SiO 2) were fabricated by E- beam evaporation. Sol-gel processing was used to... designers select laser damage resistant coatings for optical elements to be employed in military systems using lasers or encountering lasers used as

FIREBall, CHaS, and the diffuse universe

NASA Astrophysics Data System (ADS)

Hamden, Erika Tobiason

The diffuse universe, consisting of baryons that have not yet collapsed into structures such as stars, galaxies, etc., has not been well studied. While the intergalactic and circumgalactic mediums (IGM & CGM) may contain 30-40% of the baryons in the universe, this low density gas is difficult to observe. Yet it is likely a key driver of the evolution of galaxies and star formation through cosmic time. The IGM provides a reservoir of gas that can be used for star formation, if it is able to accrete onto a galaxy. The CGM bridges the IGM and the galaxy itself, as a region of both inflows from the IGM and outflows from galactic star formation and feedback. The diffuse interstellar medium (ISM) gas and dust in the galaxy itself may also be affected by the CGM of the galaxy. Careful observations of the ISM of our own Galaxy may provide evidence of interaction with the CGM. These three regions of low density, the IGM, CGM, and ISM, are arbitrary divisions of a continuous flow of low density material into and out of galaxies. My thesis focuses on observations of this low density material using existing telescopes as well as on the development of technology and instruments that will increase the sensitivity of future missions. I used data from the Galaxy Evolution Explorer (GALEX) to create an all sky map of the diffuse Galactic far ultraviolet (FUV) background, probing the ISM of our own galaxy and comparing to other Galactic all sky maps. The FUV background is primarily due to dust scattered starlight from bright stars in the Galactic plane, and the changing intensity across the sky can be used to characterize dust scattering asymmetry and albedo. We measure a consistent low level non-scattered isotropic component to the diffuse FUV, which may be due in small part to an extragalactic component. There are also several regions of unusually high FUV intensity given other Galactic quantities. Such regions may be the location of interactions between Galactic super-bubbles and the CGM. Other ways of probing the CGM including direct detection via emission lines. I built a proto-type of the Circumgalactic Halpha Spectrograph (CHalphaS), a wide-field, low-cost, narrow-band integral field unit (IFU) that is designed to observe Halpha emission from the CGM of nearby, low-z galaxies. This proto-type has had two recent science runs, with preliminary data on several nearby galaxies. Additional probes of the CGM are emission lines in the rest ultra-violet. These include OVI, Lyalpha, CIV, SiIII, CIII, CII, FeII, and MgII. Such lines are accessible for low redshift galaxies in the space UV, historically a difficult wavelength range in which to work due in part to low efficiency of the available detectors. I have worked with NASA's Jet Propulsion Laboratory to develop advanced anti-reflection (AR) coatings for use on thinned, delta-doped charge coupled device (CCD) detectors. These detectors have achieved world record quantum efficiency (QE) at UV wavelengths (>50% between 130 nm and 300nm), with the potential for even greater QE with a more complex coating. One of these AR coated detectors will be used on the Faint Intergalactic Redshifted Emission Balloon (FIREBall-2), a balloon-born UV spectrograph designed to observe the CGM at 205 nm via redshifted Lyalpha (at z=0.7), CIV (at z=0.3), and OVI (at z=1.0). FIREBall-2 will launch in the fall of 2015.

Design of an α-helical antimicrobial peptide with improved cell-selective and potent anti-biofilm activity

PubMed Central

Zhang, Shi-Kun; Song, Jin-wen; Gong, Feng; Li, Su-Bo; Chang, Hong-Yu; Xie, Hui-Min; Gao, Hong-Wei; Tan, Ying-Xia; Ji, Shou-Ping

2016-01-01

AR-23 is a melittin-related peptide with 23 residues. Like melittin, its high α-helical amphipathic structure results in strong bactericidal activity and cytotoxicity. In this study, a series of AR-23 analogues with low amphipathicity were designed by substitution of Ala1, Ala8 and Ile17 with positively charged residues (Arg or Lys) to study the effect of positively charged residue distribution on the biological viability of the antimicrobial peptide. Substitution of Ile17 on the nonpolar face with positively charged Lys dramatically altered the hydrophobicity, amphipathicity, helicity and the membrane-penetrating activity against human cells as well as the haemolytic activity of the peptide. However, substitution on the polar face only slightly affected the peptide biophysical properties and biological activity. The results indicate that the position rather than the number of positively charged residue affects the biophysical properties and selectivity of the peptide. Of all the analogues, A(A1R, A8R, I17K), a peptide with Ala1-Arg, Ala8-Arg and Ile17-Lys substitutions, exhibited similar bactericidal activity and anti-biofilm activity to AR-23 but had much lower haemolytic activity and cytotoxicity against mammalian cells compared with AR-23. Therefore, the findings reported here provide a rationalization for peptide design and optimization, which will be useful for the future development of antimicrobial agents. PMID:27271216