Structural and mechanical properties of hydroxyapatite coatings formed by ion-beam assisted deposition

NASA Astrophysics Data System (ADS)

Zykova, A.; Safonov, V.; Dudin, S.; Yakovin, S.; Donkov, N.; Ghaemi, M. H.; Szkodo, M.; Antoszkiewicz, M.; Szyfelbain, M.; Czaban, A.

2018-03-01

The ion-beam assisted deposition (IBAD) is an advanced method capable of producing crystalline coatings at low temperatures. We determined the characteristics of hydroxyapatite Ca10(PO4)6(OH)2 target and coatings formed by IBAD using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX). The composition of the coatings’ cross-section and surface was close to those of the target. The XPS spectra showed that the binding energy values of Ca (2p1/2, 2p3/2), P (2p3/2), and O 1s levels are related to the hydroxyapatite phase. The coatings demonstrate an optimal H/E ratio, and a good resistance to scratch tests.

Structural Analysis of a Carbon Nitride Film Prepared by Ion-Beam-Assisted Deposition

NASA Astrophysics Data System (ADS)

Hayashi, Toshiyuki; Matsumuro, Akihito; Muramatsu, Mutsuo; Kohzaki, Masao; Takahashi, Yutaka; Yamaguchi, Katsumi

1999-04-01

The microstructure of a carbon nitride (CNx) film formed by ion-beam-assisted deposition (IBAD) was investigated by transmission electron microscopy (TEM). This film was formed on the Si (100) substrate by IBAD with an N/C transport ratio of 1. Three different spacings (0.34 nm, 0.21 nm, 0.12 nm) were observed by transmission electron diffraction (TED) and the periodic structure corresponding to the spacing of 0.34 nm was aligned perpendicular to the substrate. The bending of this plane resembled a carbon nanotube; therefore, it seemed reasonable to suppose that the CNx film obtained consisted of numerous carbon-nanotube-like structural elements grown vertically, relative to the substrate, and it also seemed appropriate that these structural elements should be termed nanotube-like carbon nitride.

Investigation for surface resistance of yttrium-barium-copper-oxide thin films on various substrates for microwave applications

NASA Astrophysics Data System (ADS)

Yao, Hongjun

High temperature superconducting (HTS) materials such as YBCO (Yttrium-Barium-Copper-Oxide) are very attractive in microwave applications because of their extremely low surface resistance. In the proposed all-HTS tunable filter, a layer of HTS thin film on a very thin substrate (100 mum) is needed to act as the toractor that can be rotated to tune the frequency. In order to provide more substrate candidates that meet both electrical and mechanical requirements for this special application, surface resistance of YBCO thin films on various substrates was measured using microstrip ring resonator method. For alumina polycrystalline substrate, a layer of YSZ (Yttrium stabilized Zirconia) was deposited using IBAD (ion beam assisted deposition) method prior to YBCO deposition. The surface resistance of the YBCO thin film on alumina was found to be 22 mO due to high-angle grain boundary problem caused by the mixed in-plane orientations and large FWHM (full width at half maximum) of the thin film. For YBCO thin films on a YSZ single crystal substrate, the surface resistance showed even higher value of 30 mO because of the mixed in-plane orientation problem. However, by annealing the substrate in 200 Torr oxygen at 730°C prior to deposition, the in-plane orientation of YBCO thin films can be greatly improved. Therefore, the surface resistance decreased to 1.4 mO, which is still more than an order higher than the reported best value. The YBCO thin films grown on LaAlO3 single crystal substrate showed perfect in-plane orientation with FWHM less 1°. The surface resistance was as low as 0.032 mO. A tunable spiral resonator made of YBCO thin film on LaAlO3 single crystal substrate demonstrated that the resonant frequency can be tuned in a rang as large as 500 MHz by changing the gap between toractor and substrate. The Q-factor was more than 12,000, which ensured the extraordinarily high sensitivity for the proposed all-HTS tunable filter.

Influences of the residual argon gas and thermal annealing on Ta2O5 and SiO2 thin film filters

NASA Astrophysics Data System (ADS)

Liu, Wen-Jen; Chen, Chih-Min; Lai, Yin-Chieh

2005-04-01

Ion beam assisted deposition (IBAD) technique had widely used for improving stacking density and atomic mobility of thin films in many applications, especially adopted in optical film industries. Tantalum pentaoxide (Ta2O5) and silicon oxides (SiO2) optical thin films were deposited on the quartz glass substrate by using argon ion beam assisted deposition, and the influences of the residual argon gas and thermal annealing processes on the optical property, stress, compositional and microstructure evolution of the thin films were investigated in this study. Ta2O5 thin films were analyzed by XPS indicated that the ratio value of oxygen to tantalum was insufficient, at the same time, the residual argon gas in the thin films might result in film and device instabilities. Adopting oxygen-thermal annealing treatment at the temperature of 425°C, the thin films not only decreased the residual argon gas and the surface roughness, but also provided the sufficient stoichiometric ratio. Simultaneously, microstructure examination indicated few nano-crystallized structures and voids existed in Ta2O5 thin films, and possessed reasonable refractive index and lower extinction coefficient. By the way, we also suggested the IBAD system using the film compositional gas ion beam to replace the argon ion beam for assisting deposited optical films. The designed (HL)6H6LH(LH)6 multi-layers indicated higher insertion loss than the designed (HL)68H(LH)6 multi-layers. Therefore, using the high refractive index as spacer material represented lower insertion loss.

Present status and strategy of reel-to-reel TFA-MOD process for coated conductors

NASA Astrophysics Data System (ADS)

Izumi, T.; Yoshizumi, M.; Miura, M.; Nakaoka, K.; Ichikawa, Y.; Sutoh, Y.; Miyata, S.; Fukushima, H.; Yamada, Y.; Shiohara, Y.

2009-10-01

On the research and development of a reel-to-reel TFA-MOD (Metal Organic Deposition using Trifluoro-acetates) process, a present status is reviewed and its future strategy is addressed. As a base of the study, the 90 m long tape with uniform I c distribution of the 300 A/cm-width level was obtained on the CeO 2 buffered IBAD-Gd 2Zr 2O 7/Hastelloy C276 substrate. The tape has the 56 m region with the end-to-end I c value of 250 A, which corresponds to maximum product of I c × L of 14,000 Am. Based on the results, several directions on R&D have been studied such as “higher I c”, “higher I c- B”, “higher production rate both in coating/calcinations and crystallization steps” and lower cost buffer/substrate”. Then, an extremely high I c value of 735 A/cm-width was achieved in a short tape by the compositional control (e.g. Ba-deficient), in the starting solutions. On the efforts for achieving higher I c- B properties, high I c values of 115 and 35 A/cm-width under the magnetic fields of 1 and 3 T were obtained by the RE mixture of Y and Gd in REBCO, addition of Zr and a growth rate control process. On the other hand, the production rate for the coating/calcinations process was improved by development of new starting solutions, which uses F-free Y salt instead of TFA salt of Y. The high J c value of 1.9 MA/cm 2 was confirmed using the precursor films fabricated at a high traveling rate of 10 m/h. Concerning a higher rate in the crystallization step, the multi-turning system with a vertical gas flow system was developed. The validity of the concept was confirmed using 2-turn parts of the furnace. The high I c value of 250 A/cm-width was realized in the 5 m tape crystallized with a traveling rate of 3 m/h, which is equivalent to 15 m/h for usage of entire area of the furnace of 10-turns. Furthermore, in order to achieve the lower cost, the architecture of the coated conductor with a low cost buffer/substrate system has been developed. An IBAD buffered substrate using IBAD-MgO layer (CeO 2/LMO/IBAD-MgO/Hastelloy C276) was developed and a high production rate of 24 m/h was realized for IBAD-MgO layer using a small ion gun system with the area of 6 × 22 cm 2. The grain texturing of the substrate was reached the Δ ϕ value of 4° in the CeO 2 layer. This substrate was applied to the above mentioned multi-turning crystallization furnace for TFA-MOD process. Then, a 5 m long tape with 260 A/cm-width (@77 K. s.f.) was achieved. According to the TFA-MOD process in the above achievements, the prospects of each issue for the future stage were independently confirmed. Consequently, R&D combining the above-mentioned achievements for longer tapes are expected in the next stage.

Improved interface growth and enhanced flux pinning in YBCO films deposited on an advanced IBAD-MgO based template

NASA Astrophysics Data System (ADS)

Khan, M. Z.; Zhao, Y.; Wu, X.; Malmivirta, M.; Huhtinen, H.; Paturi, P.

2018-02-01

The growth mechanism is studied from the flux pinning point of view in small-scale YBa2Cu3O6+x (YBCO) thin films deposited on a polycrystalline hastelloy with advanced IBAD-MgO based buffer layer architecture. When compared the situation with YBCO films grown on single crystal substrates, the most critical issues that affect the suitable defect formation and thus the optimal vortex pinning landscape, have been studied as a function of the growth temperature and the film thickness evolution. We can conclude that the best critical current property in a wide applied magnetic field range is observed in films grown at relatively low temperature and having intermediate thickness. These phenomena are linked to the combination of the improved interface growth, to the film thickness related crystalline relaxation and to the formation of linear array of edge dislocations that forms the low-angle grain boundaries through the entire film thickness and thus improve the vortex pinning properties. Hence, the optimized buffer layer structure proved to be particularly suitable for new coated conductor solutions.

Formation of carbon nitride — a novel hard coating

NASA Astrophysics Data System (ADS)

Chubaci, J. F. D.; Ogata, K.; Fujimoto, F.; Watanabe, S.; Biersack, J. P.

1996-08-01

Increasing efforts have been reported on the formation of carbon nitride. Vapor deposition and simultaneous ion bombardment from accelerators or plasmas (IBAD) proved to be a successful technique for the preparation of this material. In our preparation, the properties of the films were controlled by varying the nitrogen ion energy and the flux composition ratio {C}/{N}. The deposited films with high nitrogen incorporation ( {C}/{N} = 0.6 ˜ 0.7 ) and low implantation energies (< 1.0 keV) showed high Knoop hardnesses of up to 63 GPa. XPS and FT-IR measurements indicated a high fraction of triple bonded CN. X-ray diffraction showed an amorphous structure. Computer simulations by the dynamic TRIM code are used to study the formation parameters, nitrogen ion energy and {C}/{N} ratio. This turned on to be useful in understanding the formation process of the carbon nitride films grown on silicon wafers, fused silica and tungsten carbide substrates.

The dependence of stress in IBAD films on the ion-irradiation energy and flux

NASA Astrophysics Data System (ADS)

Schweitz, K. O.; Arndt, J.; Bøttiger, J.; Chevallier, J.

1997-05-01

Systematic experimental studies of the stress build-up during e-gun deposition of Ni with simultaneous bombardment by energetic Ar + ions (IBAD) have been carried out. The ion energy E was varied from 60 to 800 eV, and the ratio of the arrival rates of Ni atoms and Ar + ions, {R}/{J}, was varied from 0.5 to 6.4. The Ni-deposition rate was in the range from 0.5 to 2.0 Å/s, with all the depositions carried out near room temperature in a chamber with the base pressure of 5 × 10 -6 Pa. The film stress was measured by use of profilometry and the application of Stoney's equation. The experimental results were compared with predictions of a simple model proposed by Davis. This model assumes that the compressive stress build-up, due to knock-on implantation of film atoms being proportional to E {1}/{2}, is balanced by relaxation by collision-cascade-excited atom migration proportional to E {5}/{3}. To obtain agreement between model and experiment in the investigated ranges of E and {R}/{J}, an additional model parameter had to be added which takes into account that without irradiation, tensile stresses arise.

Effect of the Cu/Ba ratio for the YBCO deposition onto IBAD template by the MOCVD method

NASA Astrophysics Data System (ADS)

Choi, J. K.; Kim, H. J.; Jun, B. H.; Kim, C. J.

2005-10-01

YBa2Cu3O7-x (YBCO) thin films were fabricated by the metal organic chemical vapor deposition (MOCVD) using a single liquid source. The copper/barium (Cu/Ba) ratio was varied from 1.26 to 1.38 to optimize the deposition condition. The IBAD template (CeO2/YSZ/stainless steel) was used as a substrate. The growth features of the YBCO films were not significantly influenced by the Cu/Ba ratio, while the superconducting transition temperature (Tc) and critical current (Ic) depended on the Cu/Ba ratio. When Cu/Ba ratio was between 1.26 and 1.29, Tc was as low as 80 K, while as Cu/Ba ratio increased to 1.38, it increased to above 85 K. The highest Tc (89.0 K) and Ic (46.3 A/cm-width) were achieved at the Cu/Ba ratio of 1.38 (Y:Ba:Cu = 1:2.1:2.9). It indicates that the optimum Cu/Ba ratio which differs from stoichiometric balance exists for the formation of the superconducting phase with a high Tc and Ic in MOCVD method.

Topography evolution of rough-surface metallic substrates by solution deposition planarization method

NASA Astrophysics Data System (ADS)

Chu, Jingyuan; Zhao, Yue; Liu, Linfei; Wu, Wei; Zhang, Zhiwei; Hong, Zhiyong; Li, Yijie; Jin, Zhijian

2018-01-01

As an emerging technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention on the fabrication of the second generation high temperature superconducting (2G-HTS) tapes. In our work, a number of amorphous oxide layers were deposited on electro-polished or mirror-rolled metallic substrates by chemical solution route. Topography evolution of surface defects on these two types of metallic substrates was thoroughly investigated by atomic force microscopy (AFM). It was showed that root mean square roughness values (at 50 × 50 μm2 scanning scale) on both rough substrates reduced to ∼5 nm after coating with SDP-layer. The smoothing effect was mainly attributed to decrease of the depth at grain boundary grooving on the electro-polished metallic substrate. On the mirror-rolled metallic substrates, the amplitude and frequency of the height fluctuation perpendicular to the rolling direction were gradually reduced as depositing more numbers of SDP-layer. A high Jc value of 4.17 MA cm-2 (at 77 K, s.f.) was achieved on a full stack of YBCO/CeO2/IBAD-MgO/SDP-layer/C276 sample. This study enhanced understanding of the topography evolution on the surface defects covered by the SDP-layer, and demonstrated a low-cost route for fabricating IBAD-MgO based YBCO templates with a simplified architecture.

Surface scaling analysis of textured MgO thin films fabricated by energetic particle self-assisted deposition

NASA Astrophysics Data System (ADS)

Feng, Feng; Zhang, Xiangsong; Qu, Timing; Liu, Binbin; Huang, Junlong; Li, Jun; Xiao, Shaozhu; Han, Zhenghe; Feng, Pingfa

2018-04-01

In the fabrication of a high-temperature superconducting coated conductor, the surface roughness and texture of buffer layers can significantly affect the epitaxially grown superconductor layer. A biaxially textured MgO buffer layer fabricated by ion beam assisted deposition (IBAD) is widely used in the coated conductor manufacture due to its low thickness requirement. In our previous study, a new method called energetic particle self-assisted deposition (EPSAD), which employed only a sputtering deposition apparatus without an ion source, was proposed for fabricating biaxially textured MgO films on non-textured substrates. In this study, our aim was to investigate the deposition mechanism of EPSAD-MgO thin films. The behavior of the surface roughness (evaluated by Rq) was studied using atomic force microscopy (AFM) measurements with three scan scales, while the in-plane and out-of-plane textures were measured using X-ray diffraction (XRD). It was found that the variations of surface roughness and textures along with the increase in the thickness of EPSAD-MgO samples were very similar to those of IBAD-MgO reported in the literature, revealing the similarity of their deposition mechanisms. Moreover, fractal geometry was utilized to conduct the scaling analysis of EPSAD-MgO film's surface. Different scaling behaviors were found in two scale ranges, and the indications of the fractal properties in different scale ranges were discussed.

Army Depot Maintenance: More Effective Use of Organic and Contractor Resources

DTIC Science & Technology

1990-06-04

terkerrny (PA) RRAD Red River (TX) IBAD Lexingtor).Bluegrass (KY) 3MPUAD Pueblo (CO) 2000 ANAD CCAD TEAD TOAD SAAO LEAD FMD LBAD PUAfl j] Aut)’onzed Onboard...until it is received by the contractor. That problem could be eliminated by redesigning the process. Specifically, the FTA document that notifies the...should revise CCSS to allow the FTM document to generate an image to LCA, the FTA to create a due-in to the contractor, and CCSS to determine the depot

Current status and future prospects of Japanese national project on coated conductor development and its applications

NASA Astrophysics Data System (ADS)

Shiohara, Y.; Yoshizumi, M.; Izumi, T.; Yamada, Y.

2008-09-01

Four years of the current five-year national project since 2003 for development of coated conductors using Y-system superconductors have passed and lots of remarkable results have been achieved. In this paper, the current status and the future prospect of this project are reviewed. The current national project comprises several groups of national laboratories, universities and private companies. The group of high performance tape development, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting tapes on the PLD-CeO 2/IBAD-GZO buffered substrates. The high product of Ic and L equal to 112,166 A m was achieved in the 368 m-304.8 A GdBCO tape whose Ic value is mostly above 350 A/cm-w. The performance under the magnetic fields was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO 2. About 61 m long GdBCO tape with ZrO 2 doping showed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, the other group focusing on the low production cost has worked on processes of TFA-MOD and MOCVD, etc. The extremely high Ic value of 735 A/cm-w was attained in the TFA-MOD films on PLD-CeO 2/IBAD-GZO/Hastelloy C276 substrate by means of using the effect of Ba-poor nominal composition. In the efforts for long tape production, 200 m long tapes with high Ic values of 200 A/cm-w and 205 A/cm-w were obtained by MOD-YBCO/PLD-CeO 2/IBAD-GZO/Hastelloy C276 and PLD-HoBCO on buffered NiW substrate, respectively. The Ic × L value of the MOD-derived tape was 40,000 A m, which is the highest value in the world by the MOD process. Based on the above achievements on the coated conductor process development, two new additional goals were set in the project. One is the development for the extremely low cost tape and another is the development of the basic technologies for making the electric power devices including cables, transformers, motors, current-limiters and cryocoolers. Some of the new themes already revealed the marvellous results such as 15 kW motor, low AC loss coils, low AC loss cables, etc.

Growth dynamics controllable deposition of homoepitaxial MgO films on the IBAD-MgO substrates

NASA Astrophysics Data System (ADS)

Wang, Wei; Liu, Lin-Fei; Yao, Yan-Jie; Lu, Sai-Dan; Wu, Xiang; Zheng, Tong; Liu, Shun-Fan; Li, Yi-Jie

2018-03-01

Homoepitaxial MgO (Homo-MgO) films, deposited by RF magnetic sputtering method in various experimental conditions, were systematically studied using growth dynamics in older to fully understand their growth mechanism. The results showed that high quality Homo-MgO films could be obtained at high oxygen partial pressure and the thickness of Homo-MgO films were seriously affected by the ratio of O2/Ar. Moreover, an interesting phenomenon we addressed was the growth mode changed with varying the sputtering power, leading to different surface morphology. Most importantly, apart from Homo-MgO films, our theory can also be appropriate for other oxide films grown by RF magnetic sputtering technology.

Formation of qualified BaHfO3 doped Y0.5Gd0.5Ba2Cu3O7-δ film on CeO2 buffered IBAD-MgO tape by self-seeding pulsed laser deposition

NASA Astrophysics Data System (ADS)

Liu, Linfei; Wang, Wei; Yao, Yanjie; Wu, Xiang; Lu, Saidan; Li, Yijie

2018-05-01

Improvement in the in-filed transport properties of REBa2Cu3O7-δ (RE = rare earth elements, REBCO) coated conductor is needed to meet the performance requirements for various practical applications, which can be accomplished by introducing artificial pinning centers (APCs), such as second phase dopant. However, with increasing dopant level the critical current density Jc at 77 K in zero applied magnetic field decreases. In this paper, in order to improve Jc we propose a seed layer technique. 5 mol% BaHfO3 (BHO) doped Y0.5Gd0.5Ba2Cu3O7-δ (YGBCO) epilayer with an inserted seed layer was grown on CeO2 buffered ion beam assisted deposition MgO (IBAD-MgO) tape by pulsed laser deposition. The effect of the conditions employed to prepare the seed layer, including tape moving speed and chemical composition, on the quality of 5 mol% BHO doped YGBCO epilayer was systematically investigated by X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM) observations. It was found that all the samples with seed layer have higher Jc (77 K, self-field) than the 5 mol% BHO doped YGBCO film without seed layer. The seed layer could inhibit deterioration of the Jc at 77 K and self-filed. Especially, the self-seed layer (5 mol% BHO doped YGBCO seed layer) was more effective in improving the crystal quality, surface morphology and superconducting performance. At 4.2 K, the 5 mol% BHO doped YGBCO film with 4 nm thick self-seed layer had a very high flux pinning force density Fp of 860 GN/m3 for B//c under a 9 T field, and more importantly, the peak of the Fp curve was not observed.

Thermoelectric Figures of Merit of Zn4Sb3 and Zrnisn-based Half-heusler Compounds Influenced by Mev Ion-beam Bombardments

NASA Astrophysics Data System (ADS)

Budak, S.; Guner, S.; Muntele, C. I.; Ila, D.

Semiconducting β-Zn4Sb3 and ZrNiSn-based half-Heusler compound thin films with applications as thermoelectric (TE) materials were prepared using ion beam assisted deposition (IBAD). High-purity solid zinc (Zn) and antimony (Sb) were evaporated by electron beam to grow the β-Zn4Sb3 thin film while high-purity zirconium (Zr) powder and nickel (Ni) tin (Sn) powders were evaporated by electron beam to grow the ZrNiSn-based half-Heusler compound thin film. Rutherford backscattering spectrometry (RBS) was used to analyze the composition of the thin films. The grown thin films were subjected to 5 MeV Si ions bombardment for generation of nanostructures in the films. We measured the thermal conductivity, Seebeck coefficient, and electrical conductivity of these two systems before and after 5 MeV Si ions beam bombardment. The two material systems have been identified as promising TE materials for the application of thermal-to-electrical energy conversion, but the efficiency still limits their applications. The electronic energy deposited due to ionization in the track of MeV ion beam couldcause localized crystallization. The nanostructures produced by MeV ion beam can cause significant change in both the electrical and the thermal conductivity of thin films, thereby improving the efficiency. We used the 3ω-method (3rd harmonic) measurement system to measure the cross-plane thermal conductivity, the van der Pauw measurement system to measure the electrical conductivity, and the Seebeck-coefficient measurement system to measure the cross-plane Seebeck coefficient. The thermoelectric figures of merit of the two material systems were then derived by calculations using the measurement results. The MeV ion-beam bombardment was found to decrease the thermal conductivity of thin films and increase the efficiency of thermal-to-electrical energy conversion.

Macroscopically Oriented Porous Materials with Periodic Ordered Structures: From Zeolites and Metal-Organic Frameworks to Liquid-Crystal-Templated Mesoporous Materials.

PubMed

Cho, Joonil; Ishida, Yasuhiro

2017-07-01

Porous materials with molecular-sized periodic structures, as exemplified by zeolites, metal-organic frameworks, or mesoporous silica, have attracted increasing attention due to their range of applications in storage, sensing, separation, and transformation of small molecules. Although the components of such porous materials have a tendency to pack in unidirectionally oriented periodic structures, such ideal types of packing cannot continue indefinitely, generally ceasing when they reach a micrometer scale. Consequently, most porous materials are composed of multiple randomly oriented domains, and overall behave as isotropic materials from a macroscopic viewpoint. However, if their channels could be unidirectionally oriented over a macroscopic scale, the resultant porous materials might serve as powerful tools for manipulating molecules. Guest molecules captured in macroscopically oriented channels would have their positions and directions well-defined, so that molecular events in the channels would proceed in a highly controlled manner. To realize such an ideal situation, numerous efforts have been made to develop various porous materials with macroscopically oriented channels. An overview of recent studies on the synthesis, properties, and applications of macroscopically oriented porous materials is presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Guide to Orientation Materials for Refugees and their Sponsors. A Selected, Annotated Bibliography Supplement.

ERIC Educational Resources Information Center

Center for Applied Linguistics, Washington, DC. Language and Orientation Resource Center.

An annotated bibliography of materials for the orientation of refugees and their sponsors is a supplement to "A Guide to Orientation Materials for Indochinese Refugees and their Sponsors," and includes 40 entries for materials pertinent to many other, non-Indochinese refugee groups. The materials are grouped alphabetically by the…

Report on the workshop on Ion Implantation and Ion Beam Assisted Deposition

NASA Astrophysics Data System (ADS)

Dearnaley, G.

1992-03-01

This workshop was organized by the Corpus Christi Army Depot (CCAD), the major helicopter repair base within AVSCOM. Previous meetings had revealed a strong interest throughout DoD in ion beam technology as a means of extending the service life of military systems by reducing wear, corrosion, fatigue, etc. The workshop opened with an account by Dr. Bruce Sartwell of the successful application of ion implantation to bearings and gears at NRL, and the checkered history of the MANTECH Project at Spire Corporation. Dr. James Hirvonen (AMTL) continued with a summary of successful applications to reduce wear in biomedical components, and he also described the processes of ion beam-assisted deposition (IBAD) for a variety of protective coatings, including diamond-like carbon (DLC).

Influence of deposition conditions on electrical and mechanical properties of Sm2O3-doped CeO2 thin films prepared by EB-PVD (+IBAD) methods. Part 1: Effective relative permittivity

NASA Astrophysics Data System (ADS)

Hartmanová, Mária; Nádaždy, Vojtech; Kundracik, František; Mansilla, Catina

2013-03-01

Study is devoted to the effective relative permittivity ɛr of CeO2 + x. Sm2O3 thin films prepared by electron-beam physical vapour deposition and ionic beam-assisted deposition methods; ɛr was investigated by three independent ways from the bulk parallel capacitance Cp, impedance capacitance Cimp, and accumulation capacitance Cacc in dependence on the deposition conditions (deposition temperature, dopant amount x and Ar+ ion bombardment during the film deposition) used. Investigations were performed using impedance spectroscopy, capacitance-voltage and current-voltage characteristics as well as deep level transient spectroscopy. Results obtained are described and discussed.

Three-Dimensional Stress Fields and Slip Systems for Single Crystal Superalloy Notched Specimens

NASA Technical Reports Server (NTRS)

Magnan, Shannon M.; Throckmorton, David (Technical Monitor)

2002-01-01

Single crystal superalloys have become increasingly popular for turbine blade and vane applications due to their high strength, and creep and fatigue resistance at elevated temperatures. The crystallographic orientation of a single crystal material greatly affects its material properties, including elastic modulus, shear modulus, and ductility. These directional properties, along with the type of loading and temperature, dictate an anisotropic response in the yield strength, creep resistance, creep rupture ductility, fatigue resistance, etc. A significant amount of research has been conducted to determine the material properties in the <001> orientation, yet the material properties deviating from the <001> orientation have not been assessed for all cases. Based on the desired application and design criteria, a crystal orientation is selected to yield the maximum properties. Currently, single crystal manufacturing is able to control the primary crystallographic orientation within 15 of the target orientation, which is an acceptable deviation to meet both performance and cost guidelines; the secondary orientation is rarely specified. A common experiment is the standard load-controlled tensile test, in which specimens with different orientations can be loaded to observe the material response. The deformation behavior of single-crystal materials under tension and compression is known to be a function of not only material orientation, but also of varying microdeformation (i.e. dislocation) mechanisms. The underlying dislocation motion causes deformation via slip, and affects the activation of specific slip systems based on load and orientation. The slip can be analyzed by observing the visible traces left on the surface of the specimen from the slip activity within the single crystal material. The goal of this thesis was to predict the slip systems activated in three-dimensional stress fields of a notched tensile specimen, as a function of crystal orientation, using finite element analysis without addressing microstructural deformation mechanisms that govern their activation. Out of three orientations tested, the specimen with a [110] load orientation and a [001] growth direction had the lowest maximum resolved shear stress; this specimen orientation appears to be the best design candidate for a tensile application.

Substrate Structures For Growth Of Highly Oriented And/Or Epitaxial Layers Thereon

DOEpatents

Arendt, Paul N.; Foltyn, Stephen R.; Groves, James R.; Jia, Quanxi

2005-07-26

A composite substrate structure including a substrate, a layer of a crystalline metal oxide or crystalline metal oxynitride material upon the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the crystalline metal oxide or crystalline metal oxynitride material layer is provided together with additional layers such as one or more layers of a buffer material upon the oriented cubic oxide material layer. Jc's of 2.3×106 A/cm2 have been demonstrated with projected Ic's of 320 Amperes across a sample 1 cm wide for a superconducting article including a flexible polycrystalline metallic substrate, an inert oxide material layer upon the surface of the flexible polycrystalline metallic substrate, a layer of a crystalline metal oxide or crystalline metal oxynitride material upon the layer of the inert oxide material, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the crystalline metal oxide or crystalline metal oxynitride material layer, a layer of a buffer material upon the oriented cubic oxide material layer, and, a top-layer of a high temperature superconducting material upon the layer of a buffer material.

MeV Si ion modifications on the thermoelectric generators from Si/Si + Ge superlattice nano-layered films

NASA Astrophysics Data System (ADS)

Budak, S.; Heidary, K.; Johnson, R. B.; Colon, T.; Muntele, C.; Ila, D.

2014-08-01

The performance of thermoelectric materials and devices is characterized by a dimensionless figure of merit, ZT = S2σT/K, where, S and σ denote, respectively, the Seebeck coefficient and electrical conductivity, T is the absolute temperature in Kelvin and K represents the thermal conductivity. The figure of merit may be improved by means of raising either S or σ or by lowering K. In our laboratory, we have fabricated and characterized the performance of a large variety of thermoelectric generators (TEG). Two TEG groups comprised of 50 and 100 alternating layers of Si/Si + Ge multi-nanolayered superlattice films have been fabricated and thoroughly characterized. Ion beam assisted deposition (IBAD) was utilized to assemble the alternating sandwiched layers, resulting in total thickness of 300 nm and 317 nm for 50 and 100 layer devices, respectively. Rutherford Backscattering Spectroscopy (RBS) was employed in order to monitor the precise quantity of Si and Ge utilized in the construction of specific multilayer thin films. The material layers were subsequently impregnated with quantum dots and/or quantum clusters, in order to concurrently reduce the cross plane thermal conductivity, increase the cross plane Seebeck coefficient and raise the cross plane electrical conductivity. The quantum dots/clusters were implanted via the 5 MeV Si ion bombardment which was performed using a Pelletron high energy ion beam accelerator. We have achieved remarkable results for the thermoelectric and optical properties of the Si/Si + Ge multilayer thin film TEG systems. We have demonstrated that with optimal setting of the 5 MeV Si ion beam bombardment fluences, one can fabricate TEG systems with figures of merits substantially higher than the values previously reported.

The Effects of Fiber Orientation and Volume Fraction of Fiber on Mechanical Properties of Additively Manufactured Composite Material

NASA Astrophysics Data System (ADS)

Kuchipudi, Suresh Chandra

Additive manufacturing (AM) also known as 3D printing has tremendous advancements in recent days with a vast number of applications in industrial, automotive, architecture, consumer projects, fashion, toys, food, art, etc. Composite materials are widely used in structures with weight as a critical factor especially in aerospace industry. Recently, additive manufacturing technology, a rapidly growing innovative technology, has gained lot of importance in making composite materials. The properties of composite materials depend upon the properties of constituent's matrix and fiber. There is lot of research on effect of fiber orientation on mechanical properties of composite materials made using conventional manufacturing methods. It will be interesting and relevant to study the relationship between the fiber orientation and fiber volume with mechanical properties of additively manufactured composite materials. This thesis work presents experimental investigation of mechanical behavior like tensile strength and fatigue life with variation in fiber orientation and fiber volume fraction of 3D printed composite materials. The aim is to study the best combination of volume fraction of fiber and fiber orientation that has better fatigue strength for additive manufactured composite materials. Using this study, we can decide the type of orientation and volume percent for desired properties. This study also finds the range of fatigue limits of 3d printed composite materials.

Edge orientations of mechanically exfoliated anisotropic two-dimensional materials

NASA Astrophysics Data System (ADS)

Yang, Juntan; Wang, Yi; Li, Yinfeng; Gao, Huajian; Chai, Yang; Yao, Haimin

2018-03-01

Mechanical exfoliation is an approach widely applied to prepare high-quality two-dimensional (2D) materials for investigating their intrinsic physical properties. During mechanical exfoliation, in-plane cleavage results in new edges whose orientations play an important role in determining the properties of the as-exfoliated 2D materials especially those with high anisotropy. Here, we systematically investigate the factors affecting the edge orientation of 2D materials obtained by mechanical exfoliation. Our theoretical study manifests that the fractured direction during mechanical exfoliation is determined synergistically by the tearing direction and material anisotropy of fracture energy. For a specific 2D material, our theory enables us to predict the possible edge orientations of the exfoliated flakes as well as their occurring probabilities. The theoretical prediction is experimentally verified by examining the inter-edge angles of the exfoliated flakes of four typical 2D materials including graphene, MoS2, PtS2, and black phosphorus. This work not only sheds light on the mechanics of exfoliation of the 2D materials but also provides a new approach to deriving information of edge orientations of mechanically exfoliated 2D materials by data mining of their macroscopic geometric features.

Present status and future prospect of coated conductor development and its application in Japan

NASA Astrophysics Data System (ADS)

Shiohara, Y.; Yoshizumi, M.; Izumi, T.; Yamada, Y.

2008-03-01

The current national project on coated conductors using Y-system superconductors has been carried out over the project period (FY2003-FY2007). In this paper, the current status and the future prospect of this project are reviewed. The high performance tape development group, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting layers on PLD-CeO2/IBAD-GZO buffered substrates. A high product of Ic and L, higher than 112 166 A m, was achieved in a 368 m-304.8 A GdBCO tape whose Ic value is mostly above 350 A/cm in width. The performance under magnetic field was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO2. 61 m long GdBCO tape with ZrO2 doping showed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, another group focusing on low production cost has worked on TFA-MOD and MOCVD processes. The extremely high Ic value of 735 A/cm-w was obtained in TFA-MOD films on PLD-CeO2/IBAD-GZO/Hastelloy substrate due to the effect of Ba-poor nominal composition. In efforts towards long tape production by the SWCC group, a 200 m long tape with a high Ic value of 200 A/cm-w was obtained using a batch-type furnace. The Ic × L value of this tape was 40 000 A m, which is the highest value in the world obtained by the TFA-MOD process. Based on the above achievements in coated conductor process development, two new additional goals were set in the project. One is the development of extremely low cost tape and the other is the development of the basic technologies for making electric power devices of cables, transformers, motors, current-limiters and cryocoolers. Some of the new investigations have already revealed marvellous results, such as a 15 kW motor, low AC loss coils, low AC loss cables, etc.

The effects of substratum material and surface orientation on the developing epibenthic community on a designed artificial reef.

PubMed

Ushiama, Shinjiro; Smith, James A; Suthers, Iain M; Lowry, Michael; Johnston, Emma L

2016-10-01

Artificial reefs provide shelter and can be an important source of food for fish depending on the epibenthic community on the structure. The growth and diversity of this community is influenced by the substratum material and the surface orientation of the reef. Settlement plates of four materials (Perspex, sandstone, wood and steel) were deployed in three orientations (upwards, downwards and vertical) at a depth of 33 m on a designed artificial reef (DAR) off the coast of Sydney, Australia. After three months, the steel surfaces had lower invertebrate species richness, total abundance and diversity compared to other surfaces. Steel was not an ideal material for the initial recruitment and growth of epibenthic invertebrates. A longer duration would be required to develop a mature epibenthic community. Surface orientation had species-specific impacts. Surface material and orientation are important factors for developing epibenthic assemblages, and are thus likely to affect the broader artificial reef assemblage, including fish.

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.

High magnetic field processing of liquid crystalline polymers

DOEpatents

Smith, M.E.; Benicewicz, B.C.; Douglas, E.P.

1998-11-24

A process of forming bulk articles of oriented liquid crystalline thermoset material, the material characterized as having an enhanced tensile modulus parallel to orientation of an applied magnetic field of at least 25 percent greater than said material processed in the absence of a magnetic field, by curing a liquid crystalline thermoset precursor within a high strength magnetic field of greater than about 2 Tesla, is provided, together with a resultant bulk article of a liquid crystalline thermoset material, said material processed in a high strength magnetic field whereby said material is characterized as having a tensile modulus parallel to orientation of said field of at least 25 percent greater than said material processed in the absence of a magnetic field.

High magnetic field processing of liquid crystalline polymers

DOEpatents

Smith, Mark E.; Benicewicz, Brian C.; Douglas, Elliot P.

1998-01-01

A process of forming bulk articles of oriented liquid crystalline thermoset material, the material characterized as having an enhanced tensile modulus parallel to orientation of an applied magnetic field of at least 25 percent greater than said material processed in the absence of a magnetic field, by curing a liquid crystalline thermoset precursor within a high strength magnetic field of greater than about 2 Tesla, is provided, together with a resultant bulk article of a liquid crystalline thermoset material, said material processed in a high strength magnetic field whereby said material is characterized as having a tensile modulus parallel to orientation of said field of at least 25 percent greater than said material processed in the absence of a magnetic field.

Preferential orientation of NV defects in CVD diamond films grown on (113)-oriented substrates

NASA Astrophysics Data System (ADS)

Lesik, M.; Plays, T.; Tallaire, A.; Achard, J.; Brinza, O.; William, L.; Chipaux, M.; Toraille, L.; Debuisschert, T.; Gicquel, A.; Roch, J. F.; Jacques, V.

2015-06-01

Thick CVD diamond layers were successfully grown on (113)-oriented substrates. They exhibited smooth surface morphologies and a crystalline quality comparable to (100) electronic grade material, and much better than (111)-grown layers. High growth rates (15-50 {\\mu}m/h) were obtained while nitrogen doping could be achieved in a fairly wide range without seriously imparting crystalline quality. Electron spin resonance measurements were carried out to determine NV centers orientation and concluded that one specific orientation has an occurrence probability of 73 % when (100)-grown layers show an equal distribution in the 4 possible directions. A spin coherence time of around 270 {\\mu}s was measured which is equivalent to that reported for material with similar isotopic purity. Although a higher degree of preferential orientation was achieved with (111)-grown layers (almost 100 %), the ease of growth and post-processing of the (113) orientation make it a potentially useful material for magnetometry or other quantum mechanical applications.

Field-controlled structures in ferromagnetic cholesteric liquid crystals.

PubMed

Medle Rupnik, Peter; Lisjak, Darja; Čopič, Martin; Čopar, Simon; Mertelj, Alenka

2017-10-01

One of the advantages of anisotropic soft materials is that their structures and, consequently, their properties can be controlled by moderate external fields. Whereas the control of materials with uniform orientational order is straightforward, manipulation of systems with complex orientational order is challenging. We show that a variety of structures of an interesting liquid material, which combine chiral orientational order with ferromagnetic one, can be controlled by a combination of small magnetic and electric fields. In the suspensions of magnetic nanoplatelets in chiral nematic liquid crystals, the platelet's magnetic moments orient along the orientation of the liquid crystal and, consequently, the material exhibits linear response to small magnetic fields. In the absence of external fields, orientations of the liquid crystal and magnetization have wound structure, which can be either homogeneously helical, disordered, or ordered in complex patterns, depending on the boundary condition at the surfaces and the history of the sample. We demonstrate that by using different combinations of small magnetic and electric fields, it is possible to control reversibly the formation of the structures in a layer of the material. In such a way, different periodic structures can be explored and some of them may be suitable for photonic applications. The material is also a convenient model system to study chiral magnetic structures, because it is a unique liquid analog of a solid helimagnet.

High Temperature Superconducting Thick Films

DOEpatents

Arendt, Paul N.; Foltyn, Stephen R.; Groves, James R.; Holesinger, Terry G.; Jia, Quanxi

2005-08-23

An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, (generally the inert oxide material layer has a smooth surface, i.e., a RMS roughness of less than about 2 nm), a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer is provided together with additional layers such as at least one layer of a buffer material upon the oriented cubic oxide material layer or a HTS top-layer of YBCO directly upon the oriented cubic oxide material layer. With a HTS top-layer of YBCO upon at least one layer of a buffer material in such an article, Jc's of 1.4×106 A/cm2 have been demonstrated with projected Ic's of 210 Amperes across a sample 1 cm wide.

Mechanical alignment of particles for use in fabricating superconducting and permanent magnetic materials

DOEpatents

Nellis, William J.; Maple, M. Brian

1992-01-01

A method for mechanically aligning oriented superconducting or permanently magnetic materials for further processing into constructs. This pretreatment optimizes the final crystallographic orientation and, thus, properties in these constructs. Such materials as superconducting fibers, needles and platelets are utilized.

Improvement of orthodontic friction by coating archwire with carbon nitride film

NASA Astrophysics Data System (ADS)

Wei, Songbo; Shao, Tianmin; Ding, Peng

2011-10-01

In order to reduce frictional resistance between archwire and bracket during orthodontic tooth movement, carbon nitride (CNx) thin films were deposited on the surface of archwires with ion beam assisted deposition (IBAD). The energy-dispersive X-ray spectrometer (EDS) analysis showed that the CNx film was successfully deposited on the surface of the orthodontic wires. X-ray photoelectron spectroscopy (XPS) analysis suggested that the deposited CNx film was sp 2 carbon dominated structures, and diversiform bonds (N sbnd C, N tbnd C, et al.) coexisted in the film. The friction tests indicated that the CNx film significantly reduced the wire-bracket friction both in ambient air and in artificial saliva. The sp 2C rich structure of the CNx film as well as its protection function for the archwire was responsible for the low friction of the wire-bracket sliding system.

Effet de l'énergie du faisceau d'ions servant à l'assistance du dépôt de matériaux organiques utilisés pour réaliser des diodes électroluminescentes

NASA Astrophysics Data System (ADS)

Antony, R.; Moliton, A.; Ratier, B.

1998-06-01

Light emitting diode based on the structure ITO/Alq3/Ca-Al lead to enhanced quantum efficiency when the Alq3 active layer is obtained by IBAD (Ion Beam Assisted Deposition): with Iodine ions, the optimization (quantum efficiency multiplied by a factor10) is obtained for an ion energy equal to 100eV. La réalisation de diodes électroluminescentes basées sur la structure ITO/Alq3/Ca-Al conduit à des performances améliorées lorsque le dépôt de la couche active Alq3 est effectué avec l'assistance d'un faisceau d'ions; l'optimisation (rendement quantique interne accru d'un ordre de grandeur) correspond à des ions Iode d'énergie 100eV.

Oriented conductive oxide electrodes on SiO2/Si and glass

DOEpatents

Jia, Quanxi; Arendt, Paul N.

2001-01-01

A thin film structure is provided including a silicon substrate with a layer of silicon dioxide on a surface thereof, and a layer of cubic oxide material deposited upon the layer of silicon dioxide by ion-beam-assisted-deposition, said layer of cubic oxide material characterized as biaxially oriented. Preferably, the cubic oxide material is yttria-stabilized zirconia. Additional thin layers of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide are deposited upon the layer of yttria-stabilized zirconia. An intermediate layer of cerium oxide is employed between the yttria-stabilized zirconia layer and the lanthanum strontium cobalt oxide layer. Also, a layer of barium strontium titanium oxide can be upon the layer of biaxially oriented ruthenium oxide or lanthanum strontium cobalt oxide. Also, a method of forming such thin film structures, including a low temperature deposition of a layer of a biaxially oriented cubic oxide material upon the silicon dioxide surface of a silicon dioxide/silicon substrate is provided.

Material characterization in partially filled waveguides using inverse scattering and multiple sample orientations

NASA Astrophysics Data System (ADS)

Sjöberg, Daniel; Larsson, Christer

2015-06-01

We present a method aimed at reducing uncertainties and instabilities when characterizing materials in waveguide setups. The method is based on measuring the S parameters for three different orientations of a rectangular sample block in a rectangular waveguide. The corresponding geometries are modeled in a commercial full-wave simulation program, taking any material parameters as input. The material parameters of the sample are found by minimizing the squared distance between measured and calculated S parameters. The information added by the different sample orientations is quantified using the Cramér-Rao lower bound. The flexibility of the method allows the determination of material parameters of an arbitrarily shaped sample that fits in the waveguide.

A Guide to Orientation Materials for Indochinese Refugees and Their Sponsors. A Selected, Annotated Bibliography.

ERIC Educational Resources Information Center

Center for Applied Linguistics, Washington, DC. Language and Orientation Resource Center.

This is an annotated bibliography of orientation materials for Indochinese refugees and their sponsors. The materials have been grouped under fourteen headings: community services, consumer education, culture, education, employment, family planning and child care, finances, health, housing, legal problems, nutrition, sponsorship and resettlement,…

Inquiry-Oriented Learning Material to Increased General Physics Competence Achievement

ERIC Educational Resources Information Center

Sinuraya, Jurubahasa

2016-01-01

This study aims to produce inquiry-oriented general physics learning material to improve student learning outcome. Development steps of learning materials were adapted from the design model of Dick and Carey. Stages of development consists of three phases: planning, development, and formative evaluation and revision. Implementation of formative…

Effect of anisotropy and texture on the low cycle fatigue behavior of Inconel 718 processed via electron beam melting

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

Kirka, Michael M.; Greeley, Duncan A.; Hawkins, Charles S.

Here in this study, the impact of texture (columnar/equiax grain structure) and influence of material orientation on the low cycle fatigue (LCF) behavior of hot isostatic pressed (HIP) and heat-treated Inconel 718 fabricated through electron beam melting (EBM) is investigated. Material was tested both parallel and perpendicular (transverse) to the build direction. In all instances, the EBM HIP and heat-treated Inconel 718 performed similarly or exceeded the LCF life of wrought Inconel 718 plate and bar stock under fully reversed strain-controlled loading at 650 °C. Amongst the textures, the columnar grains oriented parallel to the build direction exhibited the highestmore » life on average compared to the transverse columnar and equiax EBM material. Further, in relation to the reference wrought material the parallel columnar grain material exhibited a greater life. While a negligible life difference was observed in the equiax grained material between the two orientations, a consistently lower accumulated inelastic strain was measured for the material loaded parallel to the build direction than the transverse orientation. Failure of the parallel columnar material occurred in a transgranular manner with cracks emanating from the surface whereas the transverse columnar material failed in a intergranular manner, with crack growth occurring through repeated rupture of oxide at the crack-tip. Finally, in the case of the equiax material, an influence of material orientation was not observed on the failure mechanism with crack propagation occurring through a combination of debonded/cracked carbides and void formation along twin boundaries resulting in a mixture of intergranular and transgranular crack propagation.« less

Effect of anisotropy and texture on the low cycle fatigue behavior of Inconel 718 processed via electron beam melting

DOE PAGES

Kirka, Michael M.; Greeley, Duncan A.; Hawkins, Charles S.; ...

2017-09-11

Here in this study, the impact of texture (columnar/equiax grain structure) and influence of material orientation on the low cycle fatigue (LCF) behavior of hot isostatic pressed (HIP) and heat-treated Inconel 718 fabricated through electron beam melting (EBM) is investigated. Material was tested both parallel and perpendicular (transverse) to the build direction. In all instances, the EBM HIP and heat-treated Inconel 718 performed similarly or exceeded the LCF life of wrought Inconel 718 plate and bar stock under fully reversed strain-controlled loading at 650 °C. Amongst the textures, the columnar grains oriented parallel to the build direction exhibited the highestmore » life on average compared to the transverse columnar and equiax EBM material. Further, in relation to the reference wrought material the parallel columnar grain material exhibited a greater life. While a negligible life difference was observed in the equiax grained material between the two orientations, a consistently lower accumulated inelastic strain was measured for the material loaded parallel to the build direction than the transverse orientation. Failure of the parallel columnar material occurred in a transgranular manner with cracks emanating from the surface whereas the transverse columnar material failed in a intergranular manner, with crack growth occurring through repeated rupture of oxide at the crack-tip. Finally, in the case of the equiax material, an influence of material orientation was not observed on the failure mechanism with crack propagation occurring through a combination of debonded/cracked carbides and void formation along twin boundaries resulting in a mixture of intergranular and transgranular crack propagation.« less

Crystallographic Orientation Identification in Multicrystalline Silicon Wafers Using NIR Transmission Intensity

NASA Astrophysics Data System (ADS)

Skenes, Kevin; Kumar, Arkadeep; Prasath, R. G. R.; Danyluk, Steven

2018-02-01

Near-infrared (NIR) polariscopy is a technique used for the non-destructive evaluation of the in-plane stresses in photovoltaic silicon wafers. Accurate evaluation of these stresses requires correct identification of the stress-optic coefficient, a material property which relates photoelastic parameters to physical stresses. The material stress-optic coefficient of silicon varies with crystallographic orientation. This variation poses a unique problem when measuring stresses in multicrystalline silicon (mc-Si) wafers. This paper concludes that the crystallographic orientation of silicon can be estimated by measuring the transmission of NIR light through the material. The transmission of NIR light through monocrystalline wafers of known orientation were compared with the transmission of NIR light through various grains in mc-Si wafers. X-ray diffraction was then used to verify the relationship by obtaining the crystallographic orientations of these assorted mc-Si grains. Variation of transmission intensity for different crystallographic orientations is further explained by using planar atomic density. The relationship between transmission intensity and planar atomic density appears to be linear.

Nanomembrane structures having mixed crystalline orientations and compositions

DOEpatents

Lagally, Max G.; Scott, Shelley A.; Savage, Donald E.

2014-08-12

The present nanomembrane structures include a multilayer film comprising a single-crystalline layer of semiconductor material disposed between two other single-crystalline layers of semiconductor material. A plurality of holes extending through the nanomembrane are at least partially, and preferably entirely, filled with a filler material which is also a semiconductor, but which differs from the nanomembrane semiconductor materials in composition, crystal orientation, or both.

Machine Learning and Infrared Thermography for Fiber Orientation Assessment on Randomly-Oriented Strands Parts.

PubMed

Fernandes, Henrique; Zhang, Hai; Figueiredo, Alisson; Malheiros, Fernando; Ignacio, Luis Henrique; Sfarra, Stefano; Ibarra-Castanedo, Clemente; Guimaraes, Gilmar; Maldague, Xavier

2018-01-19

The use of fiber reinforced materials such as randomly-oriented strands has grown in recent years, especially for manufacturing of aerospace composite structures. This growth is mainly due to their advantageous properties: they are lighter and more resistant to corrosion when compared to metals and are more easily shaped than continuous fiber composites. The resistance and stiffness of these materials are directly related to their fiber orientation. Thus, efficient approaches to assess their fiber orientation are in demand. In this paper, a non-destructive evaluation method is applied to assess the fiber orientation on laminates reinforced with randomly-oriented strands. More specifically, a method called pulsed thermal ellipsometry combined with an artificial neural network, a machine learning technique, is used in order to estimate the fiber orientation on the surface of inspected parts. Results showed that the method can be potentially used to inspect large areas with good accuracy and speed.

Machine Learning and Infrared Thermography for Fiber Orientation Assessment on Randomly-Oriented Strands Parts

PubMed Central

Maldague, Xavier

2018-01-01

The use of fiber reinforced materials such as randomly-oriented strands has grown in recent years, especially for manufacturing of aerospace composite structures. This growth is mainly due to their advantageous properties: they are lighter and more resistant to corrosion when compared to metals and are more easily shaped than continuous fiber composites. The resistance and stiffness of these materials are directly related to their fiber orientation. Thus, efficient approaches to assess their fiber orientation are in demand. In this paper, a non-destructive evaluation method is applied to assess the fiber orientation on laminates reinforced with randomly-oriented strands. More specifically, a method called pulsed thermal ellipsometry combined with an artificial neural network, a machine learning technique, is used in order to estimate the fiber orientation on the surface of inspected parts. Results showed that the method can be potentially used to inspect large areas with good accuracy and speed. PMID:29351240

Experimental study and modeling of atomic-scale friction in zigzag and armchair lattice orientations of MoS2.

PubMed

Li, Meng; Shi, Jialin; Liu, Lianqing; Yu, Peng; Xi, Ning; Wang, Yuechao

2016-01-01

Physical properties of two-dimensional materials, such as graphene, black phosphorus, molybdenum disulfide (MoS 2 ) and tungsten disulfide, exhibit significant dependence on their lattice orientations, especially for zigzag and armchair lattice orientations. Understanding of the atomic probe motion on surfaces with different orientations helps in the study of anisotropic materials. Unfortunately, there is no comprehensive model that can describe the probe motion mechanism. In this paper, we report a tribological study of MoS 2 in zigzag and armchair orientations. We observed a characteristic power spectrum and friction force values. To explain our results, we developed a modified, two-dimensional, stick-slip Tomlinson model that allows simulation of the probe motion on MoS 2 surfaces by combining the motion in the Mo layer and S layer. Our model fits well with the experimental data and provides a theoretical basis for tribological studies of two-dimensional materials.

Epitaxial growth of CZT(S,Se) on silicon

DOEpatents

Bojarczuk, Nestor A.; Gershon, Talia S.; Guha, Supratik; Shin, Byungha; Zhu, Yu

2016-03-15

Techniques for epitaxial growth of CZT(S,Se) materials on Si are provided. In one aspect, a method of forming an epitaxial kesterite material is provided which includes the steps of: selecting a Si substrate based on a crystallographic orientation of the Si substrate; forming an epitaxial oxide interlayer on the Si substrate to enhance wettability of the epitaxial kesterite material on the Si substrate, wherein the epitaxial oxide interlayer is formed from a material that is lattice-matched to Si; and forming the epitaxial kesterite material on a side of the epitaxial oxide interlayer opposite the Si substrate, wherein the epitaxial kesterite material includes Cu, Zn, Sn, and at least one of S and Se, and wherein a crystallographic orientation of the epitaxial kesterite material is based on the crystallographic orientation of the Si substrate. A method of forming an epitaxial kesterite-based photovoltaic device and an epitaxial kesterite-based device are also provided.

Assessing the Effectiveness of Student Oriented Learning Outlines (SOLOs) in an Equine Classroom

ERIC Educational Resources Information Center

Jogan, Kathleen S.

2014-01-01

This study determined if the use of the student oriented learning outline (SOLO) in a University of Arkansas equine production classroom had a positive influence in three areas: mastery of material taught, retention of material taught and voluntary positive student behaviors related to the use of course material. Thirty-one students who were…

The Fundamentals of Dislocation Transport of Hydrogen in BCC Iron.

DTIC Science & Technology

1984-10-01

4.2.1. Single Crystal Material 24 4.2.2. Polycrystalline Material 25 4.3. Single Crystal Orientation Determination 25 4.4. Straining Permeation Test 27...Test 45 4.6. Supersaturation Study 47 S. RESULTS AND DISCUSSION 50 5.1. Single Crystal Orientation Determination 50 5.1.1. Slip System Determination 58...Orientation 162 Determination B.1. Dislocation Line Direction Determination 162 B.2. Burgers Vector Determination 164

Problem Oriented Literacy Materials Preparation: A Case Study

ERIC Educational Resources Information Center

Tripathi, Virendra

1975-01-01

One of the recent innovations of significance in developing nations is the concept of linking literacy education to problems related to socio-economic development. The article describes the Problem Oriented Materials Preparation Project of Literacy House, Lucknow, India. (Author/BP)

To have or to learn? The effects of materialism on British and Chinese children's learning.

PubMed

Ku, Lisbeth; Dittmar, Helga; Banerjee, Robin

2014-05-01

This article presents a systematic attempt to examine the associations of materialism with learning in 9- to 11-year-old children in 2 countries of similar economic development but different cultural heritage. Using cross-sectional, longitudinal, and experimental methods, we test a theoretically driven model of associations among materialism, learning motivations, and learning outcomes. Convergent findings suggest that a materialist orientation in elementary school children lowers intrinsic learning motivations, fosters extrinsic learning motivations, and leads to poorer learning outcomes. Materialism was linked directly to lower exam performance, and this link was mediated by lower mastery and heightened performance goals, with patterns not differing between British and Hong Kong Chinese children (Study 1). A follow-up showed that initial materialism predicted worse exam grades 1 year later, suggesting a detrimental long-term effect on Chinese children's school performance (Study 2). We then tested relationships between materialism and learning experimentally, by priming a momentary (state) orientation toward materialism. Writing about material possessions and money affected Chinese children's learning motivations, so that they endorsed lower mastery and higher performance goals (Study 3). A video-diary materialism prime had significant effects on actual learning behaviors, leading British children to (a) choose a performance-oriented learning task over a mastery-oriented task and (b) give up on the task more quickly (Study 4). This research has important implications for personality psychology, educational policy, and future research.

Advances in ultrasonic testing of austenitic stainless steel welds. Towards a 3D description of the material including attenuation and optimisation by inversion

NASA Astrophysics Data System (ADS)

Moysan, J.; Gueudré, C.; Ploix, M.-A.; Corneloup, G.; Guy, Ph.; Guerjouma, R. El; Chassignole, B.

In the case of multi-pass welds, the material is very difficult to describe due to its anisotropic and heterogeneous properties. Anisotropy results from the metal solidification and is correlated with the grain orientation. A precise description of the material is one of the key points to obtain reliable results with wave propagation codes. A first advance is the model MINA which predicts the grain orientations in multi-pass 316-L steel welds. For flat position welding, good predictions of the grains orientations were obtained using 2D modelling. In case of welding in position the resulting grain structure may be 3D oriented. We indicate how the MINA model can be improved for 3D description. A second advance is a good quantification of the attenuation. Precise measurements are obtained using plane waves angular spectrum method together with the computation of the transmission coefficients for triclinic material. With these two first advances, the third one is now possible: developing an inverse method to obtain the material description through ultrasonic measurements at different positions.

Experimental study and modeling of atomic-scale friction in zigzag and armchair lattice orientations of MoS2

PubMed Central

Li, Meng; Shi, Jialin; Liu, Lianqing; Yu, Peng; Xi, Ning; Wang, Yuechao

2016-01-01

Abstract Physical properties of two-dimensional materials, such as graphene, black phosphorus, molybdenum disulfide (MoS2) and tungsten disulfide, exhibit significant dependence on their lattice orientations, especially for zigzag and armchair lattice orientations. Understanding of the atomic probe motion on surfaces with different orientations helps in the study of anisotropic materials. Unfortunately, there is no comprehensive model that can describe the probe motion mechanism. In this paper, we report a tribological study of MoS2 in zigzag and armchair orientations. We observed a characteristic power spectrum and friction force values. To explain our results, we developed a modified, two-dimensional, stick-slip Tomlinson model that allows simulation of the probe motion on MoS2 surfaces by combining the motion in the Mo layer and S layer. Our model fits well with the experimental data and provides a theoretical basis for tribological studies of two-dimensional materials. PMID:27877869

Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K0.5Bi0.5TiO3-BaTiO3-Na0.5Bi0.5TiO3 piezoelectric materials

PubMed Central

Maurya, Deepam; Zhou, Yuan; Wang, Yaojin; Yan, Yongke; Li, Jiefang; Viehland, Dwight; Priya, Shashank

2015-01-01

We synthesized grain-oriented lead-free piezoelectric materials in (K0.5Bi0.5TiO3-BaTiO3-xNa0.5Bi0.5TiO3 (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d33 ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectric materials. PMID:25716551

Giant strain with ultra-low hysteresis and high temperature stability in grain oriented lead-free K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-Na₀̣₅Bi₀̣₅TiO₃ piezoelectric materials

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

Maurya, Deepam; Zhou, Yuan; Wang, Yaojin

2015-02-26

We synthesized grain-oriented lead-free piezoelectric materials in (K₀̣₅Bi₀̣₅TiO₃-BaTiO₃-xNa₀̣₅Bi₀̣₅TiO₃ (KBT-BT-NBT) system with high degree of texturing along the [001]c (c-cubic) crystallographic orientation. We demonstrate giant field induced strain (~0.48%) with an ultra-low hysteresis along with enhanced piezoelectric response (d₃₃ ~ 190pC/N) and high temperature stability (~160°C). Transmission electron microscopy (TEM) and piezoresponse force microscopy (PFM) results demonstrate smaller size highly ordered domain structure in grain-oriented specimen relative to the conventional polycrystalline ceramics. The grain oriented specimens exhibited a high degree of non-180° domain switching, in comparison to the randomly axed ones. These results indicate the effective solution to the lead-free piezoelectricmore » materials.« less

Preferential orientation of metal oxide superconducting materials by mechanical means

DOEpatents

Capone, Donald W.

1990-01-01

A superconductor comprised of a polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0<.times.<0.5) is capable of accommodating very large current densities. By aligning the two-dimensional Cu--O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the metal oxide material to accommodate high current densities. The orthorhombic crystalline particles have a tendency to lie down on one of the longer sides, i.e., on the a- or b-direction. Aligning the crystals in this orientation is accomplished by mechanical working of the material such as by extrusion, tape casting or slip casting, provided a single crystal powder is used as a starting material, to provide a highly oriented, e.g., approximately 90% of the crystal particles have a common orientation, superconducting matrix capable of supporting large current densities.

Preferential orientation of metal oxide superconducting materials by mechanical means

DOEpatents

Capone, D.W.

1990-11-27

A superconductor comprised of a polycrystalline metal oxide such as YBa[sub 2]Cu[sub 3]O[sub 7[minus]X] (where 0 < X < 0.5) is capable of accommodating very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the metal oxide material to accommodate high current densities. The orthorhombic crystalline particles have a tendency to lie down on one of the longer sides, i.e., on the a- or b-direction. Aligning the crystals in this orientation is accomplished by mechanical working of the material such as by extrusion, tape casting or slip casting, provided a single crystal powder is used as a starting material, to provide a highly oriented, e.g., approximately 90% of the crystal particles have a common orientation, superconducting matrix capable of supporting large current densities. 3 figs.

Collapse of elongated voids in porous energetic materials: Effects of void orientation and aspect ratio on initiation

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Schmidt, Martin J.; Udaykumar, H. S.

2017-04-01

The sensitivity of porous energetic materials depends on mesostructural heterogeneities such as voids, defects, cracks, and grain boundaries. The mesostructure of pressed explosives contains voids of arbitrary shapes including elongated voids of various orientations and aspect ratios. Mesoscale simulations to date have analyzed the effect of void morphology on the sensitivity of energetic materials for idealized shapes such as cylindrical, conical, and elliptical. This work analyzes the sensitivity behavior of elongated voids in an HMX matrix subject to shock loading. Simulations show that sensitivity of elongated voids depends strongly on orientation as well as aspect ratio. Ranges of orientations and aspects ratios are identified that enhance or inhibit initiation. Insights obtained from single elongated void analyses are used to identify sensitive locations in an imaged mesostructure of a pressed explosive sample.

Evaluation of the Effect of Laboratory-Oriented Science Curriculum Materials on the Attitudes of Students with Reading Difficulties.

ERIC Educational Resources Information Center

Milson, James L.

1979-01-01

Investigated how the use of laboratory-oriented science curriculum materials affected the attitudes of students with reading difficulties. Both the ninth grade experimental and control classes used a six-week instructional unit on heat and temperature. (HM)

Effects of material properties and object orientation on precision grip kinematics.

PubMed

Paulun, Vivian C; Gegenfurtner, Karl R; Goodale, Melvyn A; Fleming, Roland W

2016-08-01

Successfully picking up and handling objects requires taking into account their physical properties (e.g., material) and position relative to the body. Such features are often inferred by sight, but it remains unclear to what extent observers vary their actions depending on the perceived properties. To investigate this, we asked participants to grasp, lift and carry cylinders to a goal location with a precision grip. The cylinders were made of four different materials (Styrofoam, wood, brass and an additional brass cylinder covered with Vaseline) and were presented at six different orientations with respect to the participant (0°, 30°, 60°, 90°, 120°, 150°). Analysis of their grasping kinematics revealed differences in timing and spatial modulation at all stages of the movement that depended on both material and orientation. Object orientation affected the spatial configuration of index finger and thumb during the grasp, but also the timing of handling and transport duration. Material affected the choice of local grasp points and the duration of the movement from the first visual input until release of the object. We find that conditions that make grasping more difficult (orientation with the base pointing toward the participant, high weight and low surface friction) lead to longer durations of individual movement segments and a more careful placement of the fingers on the object.

Spring design for use in the core of a nuclear reactor

DOEpatents

Willard, Jr., H. James

1993-01-01

A spring design particularly suitable for use in the core of a nuclear reactor includes one surface having a first material oriented in a longitudinal direction, and another surface having a second material oriented in a transverse direction. The respective surfaces exhibit different amounts of irraditation induced strain.

Occupational Orientation: Applied Biological and Agricultural Occupations. Experimental Curriculum Materials.

ERIC Educational Resources Information Center

Illinois State Office of Education, Springfield.

These experimental curriculum materials, from one of five clusters developed for the occupational orientation program in Illinois, include a series of learning activity packages (LAPs) designed to acquaint the student with the wide range of occupational choices available in the applied biological and agricultural occupations. The 30 LAPs, each…

Reconstruction of the domain orientation distribution function of polycrystalline PZT ceramics using vector piezoresponse force microscopy.

PubMed

Kratzer, Markus; Lasnik, Michael; Röhrig, Sören; Teichert, Christian; Deluca, Marco

2018-01-11

Lead zirconate titanate (PZT) is one of the prominent materials used in polycrystalline piezoelectric devices. Since the ferroelectric domain orientation is the most important parameter affecting the electromechanical performance, analyzing the domain orientation distribution is of great importance for the development and understanding of improved piezoceramic devices. Here, vector piezoresponse force microscopy (vector-PFM) has been applied in order to reconstruct the ferroelectric domain orientation distribution function of polished sections of device-ready polycrystalline lead zirconate titanate (PZT) material. A measurement procedure and a computer program based on the software Mathematica have been developed to automatically evaluate the vector-PFM data for reconstructing the domain orientation function. The method is tested on differently in-plane and out-of-plane poled PZT samples, and the results reveal the expected domain patterns and allow determination of the polarization orientation distribution function at high accuracy.

A fiber orientation-adapted integration scheme for computing the hyperelastic Tucker average for short fiber reinforced composites

NASA Astrophysics Data System (ADS)

Goldberg, Niels; Ospald, Felix; Schneider, Matti

2017-10-01

In this article we introduce a fiber orientation-adapted integration scheme for Tucker's orientation averaging procedure applied to non-linear material laws, based on angular central Gaussian fiber orientation distributions. This method is stable w.r.t. fiber orientations degenerating into planar states and enables the construction of orthotropic hyperelastic energies for truly orthotropic fiber orientation states. We establish a reference scenario for fitting the Tucker average of a transversely isotropic hyperelastic energy, corresponding to a uni-directional fiber orientation, to microstructural simulations, obtained by FFT-based computational homogenization of neo-Hookean constituents. We carefully discuss ideas for accelerating the identification process, leading to a tremendous speed-up compared to a naive approach. The resulting hyperelastic material map turns out to be surprisingly accurate, simple to integrate in commercial finite element codes and fast in its execution. We demonstrate the capabilities of the extracted model by a finite element analysis of a fiber reinforced chain link.

The Improvement of Utilization Ratio of Metal Organic Sources for the Low Cost Preparation of MOCVD-synthesized YBCO Films based on a Self-heating Technology

NASA Astrophysics Data System (ADS)

Zhao, Ruipeng; Liu, Qing; Xia, Yudong; Tao, Bowan; Li, Yanrong

2017-12-01

We have successfully applied metal organic chemical vapor deposition (MOCVD) to synthesize biaxially textured YBa2Cu3O7-δ (YBCO) superconducting films on the templates of LaMnO3/epitaxial MgO/IBAD-MgO/solution deposition planarization (SDP) Y2O3/Hastelloy tape. The YBCO films have obtained dense and smooth surface with good structure and performance. A new self-heating method, which replaced the conventional heating-wire radiation heating method, has been used to heat the Hastelloy metal tapes by us. Compared with the heating-wire radiation heating method, the self-heating method shows higher energy efficiency and lower power consumption, which has good advantage to simplify the structure of the MOCVD system. Meanwhile, the utilization ratio of metal organic sources can be increased from 6% to 20% through adopting the new self-heating method. Then the preparation cost of the YBCO films can be also greatly reduced.

The Development of an Orientation Brochure for Commuter Students at Mount Vernon Nazarene College.

ERIC Educational Resources Information Center

Bolender, Ronald

This study examined the necessary elements for the development of a student orientation brochure for commuter students at Mount Vernon Nazarene College in Mount Vernon, Ohio. It reviewed nontraditional and commuter student literature and 10 commuter student brochures and orientation materials from other institutions. The orientation brochure that…

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

Josefsson, Gabriella; Gamstedt, E. Kristofer; Ahvenainen, Patrik

The mechanical performance of materials reinforced by cellulose nanofibrils is highly affected by the orientation of these fibrils. This paper investigates the nanofibril orientation distribution of films of partly oriented cellulose nanofibrils. Stripes of hydrogel films were subjected to different amount of strain and, after drying, examined with X-ray diffraction to obtain the orientation of the nanofibrils in the films, caused by the stretching. The cellulose nanofibrils had initially a random in-plane orientation in the hydrogel films and the strain was applied to the films before the nanofibrils bond tightly together, which occurs during drying. The stretching resulted in amore » reorientation of the nanofibrils in the films, with monotonically increasing orientation towards the load direction with increasing strain. Estimation of nanofibril reorientation by X-ray diffraction enables quantitative comparison of the stretch-induced orientation ability of different cellulose nanofibril systems. The reorientation of nanofibrils as a consequence of an applied strain is also predicted by a geometrical model of deformation of nanofibril hydrogels. Conversely, in high-strain cold-drawing of wet cellulose nanofibril materials, the enhanced orientation is promoted by slipping of the effectively stiff fibrils.« less

Enhanced protective role in materials with gradient structural orientations: Lessons from Nature.

PubMed

Liu, Zengqian; Zhu, Yankun; Jiao, Da; Weng, Zhaoyong; Zhang, Zhefeng; Ritchie, Robert O

2016-10-15

Living organisms are adept at resisting contact deformation and damage by assembling protective surfaces with spatially varied mechanical properties, i.e., by creating functionally graded materials. Such gradients, together with multiple length-scale hierarchical structures, represent the two prime characteristics of many biological materials to be translated into engineering design. Here, we examine one design motif from a variety of biological tissues and materials where site-specific mechanical properties are generated for enhanced protection by adopting gradients in structural orientation over multiple length-scales, without manipulation of composition or microstructural dimension. Quantitative correlations are established between the structural orientations and local mechanical properties, such as stiffness, strength and fracture resistance; based on such gradients, the underlying mechanisms for the enhanced protective role of these materials are clarified. Theoretical analysis is presented and corroborated through numerical simulations of the indentation behavior of composites with distinct orientations. The design strategy of such bioinspired gradients is outlined in terms of the geometry of constituents. This study may offer a feasible approach towards generating functionally graded mechanical properties in synthetic materials for improved contact damage resistance. Living organisms are adept at resisting contact damage by assembling protective surfaces with spatially varied mechanical properties, i.e., by creating functionally-graded materials. Such gradients, together with multiple length-scale hierarchical structures, represent the prime characteristics of many biological materials. Here, we examine one design motif from a variety of biological tissues where site-specific mechanical properties are generated for enhanced protection by adopting gradients in structural orientation at multiple length-scales, without changes in composition or microstructural dimension. The design strategy of such bioinspired gradients is outlined in terms of the geometry of constituents. This study may offer a feasible approach towards generating functionally-graded mechanical properties in synthetic materials for improved damage resistance. Published by Elsevier Ltd.

Testing of SRS and RFETS Nylon Bag Material

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

Laurinat, J.E.

1998-11-03

This report compares the effects of radiation and heating on nylon bagout materials used at the Savannah River Site (SRS) and the Rocky Flats Environmental Technology Site (RFETS). Recently, to simplify the processing of sand, slag, and crucible (SS and C), FB-Line has replaced the low-density polyethylene (LDPE) and polyvinyl chloride (PVC) bags normally used to package cans of plutonium-bearing material with nylon bags. LDPE and PVC are not soluble in the nitric acid dissolver solution used in F-Canyon, so cans bagged using these materials had to be repackaged before they were added to the dissolver. Because nylon dissolves inmore » nitric acid, cans bagged in nylon can be charged to the F-Canyon dissolvers without repackaging, thereby reducing handling requirements and personnel exposure. As part of a program to process RFETS SS and C at SRS, RFETS has also begun to use a nylon bagout material. The RFETS bag materials is made from a copolymer of nylon 6 and nylon 6.9, while the SRS material is made from a nylon 6 monomer. In addition, the SRS nylon has an anti-static agent added. The RFETS nylon is slightly softer than the SRS nylon, but does not appear to be as resistant to flex cracks initiated by contact with sharp corners of the inner can containing the SS and C.2 FB-Line Operations has asked for measurement of the effects of radiation and heating on these materials. Specifically, they have requested a comparison of the material properties of the plastics before and after irradiation, a measurement of the amount of outgassing when the plastics are heated, and a calculation of the amount of radiolytic gas generation. Testing was performed on samples taken from material that is currently used in FB-Line (color coded orange) and at RFETS. The requested tests are the same tests previously performed on the original and replacement nylon and LDPE bag materials.3,4,5. To evaluate the effect of irradiation on material properties, tensile stresses and elongations to break w ere compared for unirradiated and irradiated samples. A standard ASTM method for the measurement of tensile plastic properties6 was used. Properties were measured both parallel to the direction of machining (MD) and transverse to the direction of machining (TD). Tensile strength measurements showed that the ultimate strengths of the SRS replacement bag material decreased by 22 percent in the MD orientation and 17 percent in the TD orientation after irradiation with 5 x 106 rad, a dose equivalent to about 8-9 months exposure in a plutonium can. For the RFETS material, the decreases were 23 percent in the MD orientation and 56 percent in the TD orientation. Although the 5 x 106 dose significantly degraded the properties of both materials, their strengths remained superior to those previously measured for LDPE,4 even after irradiation. Elongations to break also decreased, especially for the SRS material. The decrease for the SRS material were 86 percent in the MD orientation and 95 percent in the TD orientation. For the RFETS material, elongations to break decreased at least 18 percent in the MD orientation and 29 percent in the TD orientation. When samples of both the SRS and RFETS materials were heated in a sealed container to the maximum expected storage can temperature of about 95 C, they outgassed at pressures ranging from 16 to 22 psig. These pressure increases would not cause a can to fail. Using a representative G value of 1.6 molecules/100 ev, the amount of outgassing due to radiolysis was calculated to be negligible. In conclusion, it may be stated that the results of the strength tests and the outgassing measurements and calculations demonstrate that the SRS and RFETS replacement bag materials are acceptable substitutes for LDPE with respect to mechanical properties.« less

Unit-Sphere Multiaxial Stochastic-Strength Model Applied to Anisotropic and Composite Materials

NASA Technical Reports Server (NTRS)

Nemeth, Noel, N.

2013-01-01

Models that predict the failure probability of brittle materials under multiaxial loading have been developed by authors such as Batdorf, Evans, and Matsuo. These "unit-sphere" models assume that the strength-controlling flaws are randomly oriented, noninteracting planar microcracks of specified geometry but of variable size. This methodology has been extended to predict the multiaxial strength response of transversely isotropic brittle materials, including polymer matrix composites (PMCs), by considering (1) flaw-orientation anisotropy, whereby a preexisting microcrack has a higher likelihood of being oriented in one direction over another direction, and (2) critical strength, or K (sub Ic) orientation anisotropy, whereby the level of critical strength or fracture toughness for mode I crack propagation, K (sub Ic), changes with regard to the orientation of the microstructure. In this report, results from finite element analysis of a fiber-reinforced-matrix unit cell were used with the unit-sphere model to predict the biaxial strength response of a unidirectional PMC previously reported from the World-Wide Failure Exercise. Results for nuclear-grade graphite materials under biaxial loading are also shown for comparison. This effort was successful in predicting the multiaxial strength response for the chosen problems. Findings regarding stress-state interactions and failure modes also are provided.

Orienting Periodic Organic-Inorganic Nanoscale Domains Through One-Step Electrodeposition

PubMed Central

Herman, David J.; Goldberger, Joshua E.; Chao, Stephen; Martin, Daniel T.; Stupp, Samuel I

2011-01-01

One of the challenges in the synthesis of hybrid materials with nanoscale structure is to precisely control morphology across length scales. Using a one-step electrodeposition process on indium tin oxide (ITO) substrates followed by annealing, we report here the preparation of materials with preferentially oriented lamellar domains of electron donor surfactants and the semiconductor ZnO. We found that either increasing the concentration of surfactant or the water to dimethyl sulfoxide ratio of solutions used resulted in the suppression of bloom-like morphologies and enhanced the density of periodic domains on ITO substrates. Furthermore, by modifying the surface of the ITO substrate with the conductive polymer blend poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), we were able to alter the orientation of these electrodeposited lamellar domains to be perpendicular to the substrate. The long-range orientation achieved was characterized by 2D grazing incidence small angle X-ray scattering. This high degree of orientation in electronically active hybrids with alternating nanoscale p-type and n-type domains is of potential interest in photovoltaics or thermoelectric materials. PMID:21142087

Strain-based control of crystal anisotropy for perovskite oxides on semiconductor-based material

DOEpatents

McKee, Rodney Allen; Walker, Frederick Joseph

2000-01-01

A crystalline structure and a semiconductor device includes a substrate of a semiconductor-based material and a thin film of an anisotropic crystalline material epitaxially arranged upon the surface of the substrate so that the thin film couples to the underlying substrate and so that the geometries of substantially all of the unit cells of the thin film are arranged in a predisposed orientation relative to the substrate surface. The predisposition of the geometries of the unit cells of the thin film is responsible for a predisposed orientation of a directional-dependent quality, such as the dipole moment, of the unit cells. The predisposed orientation of the unit cell geometries are influenced by either a stressed or strained condition of the lattice at the interface between the thin film material and the substrate surface.

Inducting Newly Placed Teachers: Orientation Responsibilities of the School Administrator. OSSC Bulletin Vol. 21, No. 10.

ERIC Educational Resources Information Center

Badertscher, James A.

This bulletin is designed to provide an overview of teacher orientation practices and suggestions. Its primary audience is the building principals who find themselves responsible for orientation activities. The contents are based on extensive literature reviews, orientation materials and methods used by several selected Oregon school districts,…

Engineering of oriented carbon nanotubes in composite materials

PubMed Central

Beigmoradi, Razieh; Mohebbi-Kalhori, Davod

2018-01-01

The orientation and arrangement engineering of carbon nanotubes (CNTs) in composite structures is considered a challenging issue. In this regard, two groups of in situ and ex situ techniques have been developed. In the first, the arrangement is achieved during CNT growth, while in the latter, the CNTs are initially grown in random orientation and the arrangement is then achieved during the device integration process. As the ex situ techniques are free from growth restrictions and more flexible in terms of controlling the alignment and sorting of the CNTs, they are considered by some as the preferred technique for engineering of oriented CNTs. This review focuses on recent progress in the improvement of the orientation and alignment of CNTs in composite materials. Moreover, the advantages and disadvantages of the processes are discussed as well as their future outlook. PMID:29515955

Modeling of layered anisotropic composite material based on effective medium theory

NASA Astrophysics Data System (ADS)

Bao, Yang; Song, Jiming

2018-04-01

In this paper, we present an efficient method to simulate multilayered anisotropic composite material with effective medium theory. Effective permittivity, permeability and orientation angle for a layered anisotropic composite medium are extracted with this equivalent model. We also derive analytical expressions for effective parameters and orientation angle with low frequency (LF) limit, which will be shown in detail. Numerical results are shown in comparing extracted effective parameters and orientation angle with analytical results from low frequency limit. Good agreements are achieved to demonstrate the accuracy of our efficient model.

Thermally Stable, Piezoelectric and Pyroelectric Polymeric Substrates and Method Relating Thereto

NASA Technical Reports Server (NTRS)

Simpson, Joycelyn O. (Inventor); St.Clair, Terry L. (Inventor)

1995-01-01

Production of an electric voltage in response to mechanical excitation (piezoelectricity) or thermal excitation (pyroelectricity) requires a material to have a preferred dipole orientation in its structure. This preferred orientation or polarization occurs naturally in some crystals such as quartz and can be induced into some ceramic and polymeric materials by application of strong electric or mechanical fields. For some materials, a combination of mechanical and electrical orientation is necessary to completely polarize the material. The only commercially available piezoelectric polymer is poly(vinylidene fluoride) (PVF2). However, this polymer has material and process limitations which prohibit its use in numerous device applications where thermal stability is a requirement. By the present invention, thermally stable, piezoelectric and pyroelectric polymeric substrates were prepared from polymers having a softening temperature greater than 1000C. A metal electrode material is deposited onto the polymer substrate and several electrical leads are attached to it. The polymer substrate is heated in a low dielectric medium to enhance molecular mobility of the polymer chains. A voltage is then applied to the polymer substrate inducing polarization. The voltage is then maintained while the polymer substrate is cooled 'freezing in' the molecular orientation. The novelty of the invention resides in the process of preparing the piezoelectric and pyroelectric polymeric substrate. The nonobviousness of the invention is found in heating the polymeric substrate in a low dielectric medium while applying a voltage.

X-ray Birefringence: A New Strategy for Determining Molecular Orientation in Materials.

PubMed

Palmer, Benjamin A; Edwards-Gau, Gregory R; Morte-Ródenas, Anabel; Kariuki, Benson M; Lim, Gin Keat; Harris, Kenneth D M; Dolbnya, Igor P; Collins, Stephen P

2012-11-01

While the phenomenon of birefringence is well-established in the case of visible radiation and is exploited in many fields (e.g., through the use of the polarizing optical microscope), the analogous phenomenon for X-rays has been a virtually neglected topic. Here, we demonstrate the scope and potential for exploiting X-ray birefringence to determine the orientational properties of specific types of bonds in solids. Specifically, orientational characteristics of C-Br bonds in the bromocyclohexane/thiourea inclusion compound are elucidated from X-ray birefringence measurements at energies close to the bromine K-edge, revealing inter alia the changes in the orientational distribution of the C-Br bonds associated with a low-temperature order-disorder phase transition. From fitting a theoretical model to the experimental data, reliable quantitative information on the orientational properties of the C-Br bonds is determined. The experimental strategy reported here represents the basis of a new approach for gaining insights into the orientational properties of molecules in anisotropic materials.

A test of the double-shearing model of flow for granular materials

USGS Publications Warehouse

Savage, J.C.; Lockner, D.A.

1997-01-01

The double-shearing model of flow attributes plastic deformation in granular materials to cooperative slip on conjugate Coulomb shears (surfaces upon which the Coulomb yield condition is satisfied). The strict formulation of the double-shearing model then requires that the slip lines in the material coincide with the Coulomb shears. Three different experiments that approximate simple shear deformation in granular media appear to be inconsistent with this strict formulation. For example, the orientation of the principal stress axes in a layer of sand driven in steady, simple shear was measured subject to the assumption that the Coulomb failure criterion was satisfied on some surfaces (orientation unspecified) within the sand layer. The orientation of the inferred principal compressive axis was then compared with the orientations predicted by the double-shearing model. The strict formulation of the model [Spencer, 1982] predicts that the principal stress axes should rotate in a sense opposite to that inferred from the experiments. A less restrictive formulation of the double-shearing model by de Josselin de Jong [1971] does not completely specify the solution but does prescribe limits on the possible orientations of the principal stress axes. The orientations of the principal compression axis inferred from the experiments are probably within those limits. An elastoplastic formulation of the double-shearing model [de Josselin de Jong, 1988] is reasonably consistent with the experiments, although quantitative agreement was not attained. Thus we conclude that the double-shearing model may be a viable law to describe deformation of granular materials, but the macroscopic slip surfaces will not in general coincide with the Coulomb shears.

On three-dimensional misorientation spaces.

PubMed

Krakow, Robert; Bennett, Robbie J; Johnstone, Duncan N; Vukmanovic, Zoja; Solano-Alvarez, Wilberth; Lainé, Steven J; Einsle, Joshua F; Midgley, Paul A; Rae, Catherine M F; Hielscher, Ralf

2017-10-01

Determining the local orientation of crystals in engineering and geological materials has become routine with the advent of modern crystallographic mapping techniques. These techniques enable many thousands of orientation measurements to be made, directing attention towards how such orientation data are best studied. Here, we provide a guide to the visualization of misorientation data in three-dimensional vector spaces, reduced by crystal symmetry, to reveal crystallographic orientation relationships. Domains for all point group symmetries are presented and an analysis methodology is developed and applied to identify crystallographic relationships, indicated by clusters in the misorientation space, in examples from materials science and geology. This analysis aids the determination of active deformation mechanisms and evaluation of cluster centres and spread enables more accurate description of transformation processes supporting arguments regarding provenance.

On three-dimensional misorientation spaces

NASA Astrophysics Data System (ADS)

Krakow, Robert; Bennett, Robbie J.; Johnstone, Duncan N.; Vukmanovic, Zoja; Solano-Alvarez, Wilberth; Lainé, Steven J.; Einsle, Joshua F.; Midgley, Paul A.; Rae, Catherine M. F.; Hielscher, Ralf

2017-10-01

Determining the local orientation of crystals in engineering and geological materials has become routine with the advent of modern crystallographic mapping techniques. These techniques enable many thousands of orientation measurements to be made, directing attention towards how such orientation data are best studied. Here, we provide a guide to the visualization of misorientation data in three-dimensional vector spaces, reduced by crystal symmetry, to reveal crystallographic orientation relationships. Domains for all point group symmetries are presented and an analysis methodology is developed and applied to identify crystallographic relationships, indicated by clusters in the misorientation space, in examples from materials science and geology. This analysis aids the determination of active deformation mechanisms and evaluation of cluster centres and spread enables more accurate description of transformation processes supporting arguments regarding provenance.

A research project to develop and evaluate a technical education component on materials technology for orientation to space-age technology

NASA Technical Reports Server (NTRS)

Jacobs, J. A.

1976-01-01

A project was initiated to develop, implement, and evaluate a prototype component for self-pacing, individualized instruction on basic materials science. Results of this project indicate that systematically developed, self-paced instruction provides an effective means for orienting nontraditional college students and secondary students, especially minorities, to both engineering technology and basic materials science. In addition, students using such a system gain greater chances for mastering subject matter than with conventional modes of instruction.

Magnetic self-orientation of lyotropic hexagonal phases based on long chain alkanoic (fatty) acids.

PubMed

Douliez, Jean-Paul

2010-07-06

It is presently shown that long chain (C14, C16, and C18) alkanoic (saturated fatty) acids can form magnetically oriented hexagonal phases in aqueous concentrated solutions in mixtures with tetrabutylammonium (TBAOH) as the counterion. The hexagonal phase occurred for a molar ratio, alkanoic acid/TBAOH, higher than 1, i.e., for an excess of fatty acid. The hexagonal phase melted to an isotropic phase (micelles) upon heating at a given temperature depending on the alkyl chain length. The self-orientation of the hexagonal phase occurred upon cooling from the "high-temperature" isotropic phase within the magnetic field. The long axis of the hexagonal phase was shown to self-orient parallel to the magnetic field as evidenced by deuterium solid-state NMR. This finding is expected to be of interest in the field of structural biology and materials chemistry for the synthesis of oriented materials.

Using Teachers' Inquiry-Oriented Curriculum Materials as a Means to Examine Their Pedagogical Design Capacity and Pedagogical Content Knowledge for Inquiry-Based Learning

ERIC Educational Resources Information Center

Papaevripidou, Marios; Irakleous, Maria; Zacharia, Zacharias C.

2017-01-01

The study aimed at examining preservice elementary teachers' inquiry-oriented curriculum materials in an attempt to unravel their pedagogical design capacity (PDC) and pedagogical content knowledge (PCK) for inquiry-based learning (IBL), after attending a professional development program (PDP) centered around inquiry-based teaching and learning.…

Homestay Program Orientation Manual, Including Leader's Guides and Preparatory Readings, Plus Materials for Student Use.

ERIC Educational Resources Information Center

Grove, Cornelius Lee; Hansel, Bettina

Developed as orientation materials for foreign students coming to the United States to study English, this manual contains six units to acquaint students with U.S. history, government, and culture. The first unit introduces students to the daily routines and interpersonal relationships of U.S. people. Unit 2 examines the origins and significance…

A Parent Involvement Model for Use with Limited English Proficient High School Students. Teacher's Guide: The Vocationally Oriented Bilingual Curriculum.

ERIC Educational Resources Information Center

Trinity Coll., Washington, DC.

This teaching guide accompanying materials for parents to support the efforts of their limited-English-speaking high school children in a vocationally-oriented bilingual secondary program provides an explanation of the program and its objectives and suggests techniques for introducing and using the materials effectively with the parents. Steps to…

Properties of Vector Preisach Models

NASA Technical Reports Server (NTRS)

Kahler, Gary R.; Patel, Umesh D.; Torre, Edward Della

2004-01-01

This paper discusses rotational anisotropy and rotational accommodation of magnetic particle tape. These effects have a performance impact during the reading and writing of the recording process. We introduce the reduced vector model as the basis for the computations. Rotational magnetization models must accurately compute the anisotropic characteristics of ellipsoidally magnetizable media. An ellipticity factor is derived for these media that computes the two-dimensional magnetization trajectory for all applied fields. An orientation correction must be applied to the computed rotational magnetization. For isotropic materials, an orientation correction has been developed and presented. For anisotropic materials, an orientation correction is introduced.

General Mathematics; Part 1. Mathematics Curriculum Guide (Career Oriented).

ERIC Educational Resources Information Center

Nuschler, Alexandra; And Others

The curriculum guide for secondary level, career-oriented General Mathematics Part 1, correlates performance objectives in basic mathematics with career-oriented concepts and activities. The material is designed to lead the student in a systematic development that provides for continuous progress. The guide is in outline format, providing a…

Ultrahigh density ferroelectric storage and lithography by high order ferroic switching

DOEpatents

Kalinin, Sergei V.; Baddorf, Arthur P.; Lee, Ho Nyung; Shin, Junsoo; Gruverman, Alexei L.; Karapetian, Edgar; Kachanov, Mark

2007-11-06

A method for switching the direction of polarization in a relatively small domain in a thin-film ferroelectric material whose direction of polarization is oriented normal to the surface of the material involves a step of moving an electrically-chargeable tip into contact with the surface of the ferroelectric material so that the direction of polarization in a region adjacent the tip becomes oriented in a preselected direction relative to the surface of the ferroelectric material. The tip is then pressed against the surface of the ferroelectric material so that the direction of polarization of the ferroelectric material within the area of the ferroelectric material in contact with the tip is reversed under the combined effect of the compressive influence of the tip and electric bias.

Thermoelectric materials and devices

NASA Technical Reports Server (NTRS)

Park, Yeonjoon (Inventor); Choi, Sang H. (Inventor); King, Glen C. (Inventor); Elliott, James R. (Inventor); Talcott, Noel A. (Inventor)

2011-01-01

New thermoelectric materials comprise highly [111]-oriented twinned group IV alloys on the basal plane of trigonal substrates, which exhibit a high thermoelectric figure of merit and good material performance, and devices made with these materials.

Secondary orientation effects in a single crystal superalloy under mechanical and thermal loads

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Abdul-Aziz, Ali; Mcgaw, Michael A.

1991-01-01

The nickel-base single crystal superalloy PWA 1480 is a candidate blading material for the advanced turbopump development program of the SSME. In order to improve thermal fatigue resistance of the turbine blades, the single crystal superalloy PWA 1480 is grown along the low modulus zone axes (001) crystal orientation by a directional solidification process. Since cubic single crystal materials such as PWA 1480 exhibit anisotropic elastic behavior, the stresses developed within the single crystal superalloy due to mechanical and thermal loads are likely to be affected by the exact orientation of the secondary crystallographic direction with respect to the geometry of the turbine blade. The effects of secondary crystal orientation on the elastic response of single crystal PWA 1480 superalloy were investigated.

On three-dimensional misorientation spaces

PubMed Central

Bennett, Robbie J.; Vukmanovic, Zoja; Solano-Alvarez, Wilberth; Lainé, Steven J.; Einsle, Joshua F.; Midgley, Paul A.; Rae, Catherine M. F.; Hielscher, Ralf

2017-01-01

Determining the local orientation of crystals in engineering and geological materials has become routine with the advent of modern crystallographic mapping techniques. These techniques enable many thousands of orientation measurements to be made, directing attention towards how such orientation data are best studied. Here, we provide a guide to the visualization of misorientation data in three-dimensional vector spaces, reduced by crystal symmetry, to reveal crystallographic orientation relationships. Domains for all point group symmetries are presented and an analysis methodology is developed and applied to identify crystallographic relationships, indicated by clusters in the misorientation space, in examples from materials science and geology. This analysis aids the determination of active deformation mechanisms and evaluation of cluster centres and spread enables more accurate description of transformation processes supporting arguments regarding provenance. PMID:29118660

Study on preferred crystal orientations of Mg-Zr-O composite protective layer in AC-PDP

NASA Astrophysics Data System (ADS)

Bingang, G.; Chunliang, L.; Zhongxiao, S.; Liu, L.; Yufeng, F.; Xing, X.; Duowang, F.

2006-11-01

In order to study the preferred crystal orientations of Mg-Zr-O composite protective layers in PDP, Mg-Zr-O composite protective layers were deposited by Electron-beam Evaporator using (MgO+ZrO{2}) powder mixture as evaporation source material. X-ray diffractometer (XRD) was used to determine preferred crystal orientations of Mg-Zr-O composite protective layers, surface morphologies of films were analyzed by FESEM and voltage characteristics were examined in a testing macroscopic discharge cell of AC-PDP. On the basis of experimental analysis, the influence of oxide addition and deposition conditions on preferred orientations of Mg-Zr-O composite protective layers were investigated. The results showed that the preferred orientations of Mg-Zr-O films were determined by lattice distortion of MgO crystal. The deposition conditions have great effects on the preferred orientations of Mg-Zr-O films. The preferred orientations affect voltage characteristics through affecting surface morphology of Mg-Zr-O films. A small amount of Zr solution in MgO can decrease firing voltage compared with using pure MgO film. Firing voltage is closely related with the [ ZrO{2}/(MgO+ZrO{2})] ratio of evaporation source materials.

Embedded sensor having an identifiable orientation

DOEpatents

Bennett, Thomas E.; Nelson, Drew V.

2002-01-01

An apparatus and method is described wherein a sensor, such as a mechanical strain sensor, embedded in a fiber core, is "flagged" to identify a preferred orientation of the sensor. The identifying "flag" is a composite material, comprising a plurality of non-woven filaments distributed in a resin matrix, forming a small planar tab. The fiber is first subjected to a stimulus to identify the orientation providing the desired signal response, and then sandwiched between first and second layers of the composite material. The fiber, and therefore, the sensor orientation is thereby captured and fixed in place. The process for achieving the oriented fiber includes, after identifying the fiber orientation, carefully laying the oriented fiber onto the first layer of composite, moderately heating the assembled layer for a short period in order to bring the composite resin to a "tacky" state, heating the second composite layer as the first, and assembling the two layers together such that they merge to form a single consolidated block. The consolidated block achieving a roughly uniform distribution of composite filaments near the embedded fiber such that excess resin is prevented from "pooling" around the periphery of the fiber.

Feasibility on fiber orientation detection on unidirectional CFRP composite laminates using nondestructive evaluation techniques

NASA Astrophysics Data System (ADS)

Yang, In-Young; Kim, Ji-Hoon; Cha, Cheon-Seok; Lee, Kil-Sung; Hsu, David K.; Im, Kwang-Hee

2007-07-01

In particular, CFRP (carbon fiber reinforced plastics) composite materials have found wide applicability because of their inherent design flexibility and improved material properties. CFRP composites were manufactured from uni-direction prepreg sheet in this paper. It is important to assess fiber orientation, material properties and part defect in order to ensure product quality and structural integrity of CFRP because strength and stiffness of composites depend on fiber orientation. It is desirable to perform nondestructive evaluation which is very beneficial. An new method for nondestructively determining the fiber orientation in a composite laminate is presented. A one-sided pitch-catch setup was used in the detection and evaluation of flaws and material anomalies in the unidirectional CFRP composite laminates. Two Rayleigh wave transducers were joined head-to-head and used in the pitch-catch mode on the surface of the composites. The pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to subtle flaw conditions in the composite. Especially, ultrasonic waves were extensively characterized in the CFRP composite laminates both normal to fiber and along to fiber with using a one-sided direction of Rayleigh wave transducers. Also, one-sided ultrasonic measurement was made with using a Rayleigh wave transducers and a conventional scanner was used in an immersion tank for extracting fiber orientation information from the ultrasonic reflection in the unidirectional laminate. Therefore, it is thought that the proposed method is useful to evaluate integrity of CFRP laminates.

Buffer layers on metal alloy substrates for superconducting tapes

DOEpatents

Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

2004-06-29

An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected IC's of over 200 Amperes across a sample 1 cm wide.

Monte Carlo modelling the dosimetric effects of electrode material on diamond detectors.

PubMed

Baluti, Florentina; Deloar, Hossain M; Lansley, Stuart P; Meyer, Juergen

2015-03-01

Diamond detectors for radiation dosimetry were modelled using the EGSnrc Monte Carlo code to investigate the influence of electrode material and detector orientation on the absorbed dose. The small dimensions of the electrode/diamond/electrode detector structure required very thin voxels and the use of non-standard DOSXYZnrc Monte Carlo model parameters. The interface phenomena was investigated by simulating a 6 MV beam and detectors with different electrode materials, namely Al, Ag, Cu and Au, with thickens of 0.1 µm for the electrodes and 0.1 mm for the diamond, in both perpendicular and parallel detector orientation with regards to the incident beam. The smallest perturbations were observed for the parallel detector orientation and Al electrodes (Z = 13). In summary, EGSnrc Monte Carlo code is well suited for modelling small detector geometries. The Monte Carlo model developed is a useful tool to investigate the dosimetric effects caused by different electrode materials. To minimise perturbations cause by the detector electrodes, it is recommended that the electrodes should be made from a low-atomic number material and placed parallel to the beam direction.

78 FR 73562 - Non-Oriented Electrical Steel From China, Germany, Japan, Korea, Sweden, and Taiwan; Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-06

... (Preliminary)] Non-Oriented Electrical Steel From China, Germany, Japan, Korea, Sweden, and Taiwan... industry in the United States is materially injured by reason of imports from China, Germany, Japan, Korea... Taiwan and LTFV imports of non-oriented electrical steel from China, Germany, Japan, Korea, Sweden, and...

Magnetic preferential orientation of metal oxide superconducting materials

DOEpatents

Capone, D.W.; Dunlap, B.D.; Veal, B.W.

1990-07-17

A superconductor comprised of a polycrystalline metal oxide such as YBa[sub 2]Cu[sub 3]O[sub 7[minus]X] (where 0 < X < 0.5) exhibits superconducting properties and is capable of conducting very large current densities. By aligning the two-dimensional Cu-O layers which carry the current in the superconducting state in the a- and b-directions, i.e., within the basal plane, a high degree of crystalline axes alignment is provided between adjacent grains permitting the conduction of high current densities. The highly anisotropic diamagnetic susceptibility of the polycrystalline metal oxide material permits the use of an applied magnetic field to orient the individual crystals when in the superconducting state to substantially increase current transport between adjacent grains. In another embodiment, the anisotropic paramagnetic susceptibility of rare-earth ions substituted into the oxide material is made use of as an applied magnetic field orients the particles in a preferential direction. This latter operation can be performed with the material in the normal (non-superconducting) state. 4 figs.

Magnetic preferential orientation of metal oxide superconducting materials

DOEpatents

Capone, Donald W.; Dunlap, Bobby D.; Veal, Boyd W.

1990-01-01

A superconductor comprised of a polycrystalline metal oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-X (where 0

Investigation of ferroelectric liquid crystal orientation in the silica microcapillaries

NASA Astrophysics Data System (ADS)

Budaszewski, D.; Domański, A. W.; Woliński, T. R.

2013-05-01

In the paper we present our recent results concerning the orientation of ferroelectric liquid crystal molecules inside silica micro capillaries. We have infiltrated the silica micro capillaries with experimental ferroelectric liquid crystal material W-260K synthesized in the Military University of Technology. The infiltrated micro capillaries were observed under the polarization microscope while both a polarizer and an analyzer were crossed. The studies on the orientation of ferroelectric liquid crystal molecules may contribute to further studies on behavior of this group of liquid crystal materials inside photonic crystal fiber. The obtained results may lead to design of a new type of fast optical fiber sensors.

Numerical Estimation of the Elastic Properties of Thin-Walled Structures Manufactured from Short-Fiber-Reinforced Thermoplastics

NASA Astrophysics Data System (ADS)

Altenbach, H.; Naumenko, K.; L'vov, G. I.; Pilipenko, S. N.

2003-05-01

A model which allows us to estimate the elastic properties of thin-walled structures manufactured by injection molding is presented. The starting step is the numerical prediction of the microstructure of a short-fiber-reinforced composite developed during the filling stage of the manufacturing process. For this purpose, the Moldflow Plastic Insight® commercial program is used. As a result of simulating the filling process, a second-rank orientation tensor characterizing the microstructure of the material is obtained. The elastic properties of the prepared material locally depend on the orientational distribution of fibers. The constitutive equation is formulated by means of orientational averaging for a given orientation tensor. The tensor of elastic material properties is computed and translated into the format for a stress-strain analysis based on the ANSYSÒ finite-element code. The numerical procedure and the convergence of results are discussed for a thin strip, a rectangular plate, and a shell of revolution. The influence of manufacturing conditions on the stress-strain state of statically loaded thin-walled elements is illustrated.

Theory and application of laser ultrasonic shear wave birefringence measurements to the determination of microstructure orientation in transversely isotropic, polycrystalline graphite materials

DOE PAGES

Zeng, Fan W.; Contescu, Cristian I.; Gallego, Nidia C.; ...

2016-12-18

Laser ultrasonic line source methods have been used to study elastic anisotropy in nuclear graphites by measuring shear wave birefringence. Depending on the manufacturing processes used during production, nuclear graphites can exhibit various degrees of material anisotropy related to preferred crystallite orientation and to microcracking. In this paper, laser ultrasonic line source measurements of shear wave birefringence on NBG-25 have been performed to assess elastic anisotropy. Laser line sources allow specific polarizations for shear waves to be transmitted – the corresponding wavespeeds can be used to compute bulk, elastic moduli that serve to quantify anisotropy. These modulus values can bemore » interpreted using physical property models based on orientation distribution coefficients and microcrack-modified, single crystal moduli to represent the combined effects of crystallite orientation and microcracking on material anisotropy. Finally, ultrasonic results are compared to and contrasted with measurements of anisotropy based on the coefficient of thermal expansion to show the relationship of results from these techniques.« less

Discrete and continuum modelling of soil cutting

NASA Astrophysics Data System (ADS)

Coetzee, C. J.

2014-12-01

Both continuum and discrete methods are used to investigate the soil cutting process. The Discrete Element Method ( dem) is used for the discrete modelling and the Material-Point Method ( mpm) is used for continuum modelling. M pmis a so-called particle method or meshless finite element method. Standard finite element methods have difficulty in modelling the entire cutting process due to large displacements and deformation of the mesh. The use of meshless methods overcomes this problem. M pm can model large deformations, frictional contact at the soil-tool interface, and dynamic effects (inertia forces). In granular materials the discreteness of the system is often important and rotational degrees of freedom are active, which might require enhanced theoretical approaches like polar continua. In polar continuum theories, the material points are considered to possess orientations. A material point has three degrees-of-freedom for rigid rotations, in addition to the three classic translational degrees-of-freedom. The Cosserat continuum is the most transparent and straightforward extension of the nonpolar (classic) continuum. Two-dimensional dem and mpm (polar and nonpolar) simulations of the cutting problem are compared to experiments. The drag force and flow patterns are compared using cohesionless corn grains as material. The corn macro (continuum) and micro ( dem) properties were obtained from shear and oedometer tests. Results show that the dilatancy angle plays a significant role in the flow of material but has less of an influence on the draft force. Nonpolar mpm is the most accurate in predicting blade forces, blade-soil interface stresses and the position and orientation of shear bands. Polar mpm fails in predicting the orientation of the shear band, but is less sensitive to mesh size and mesh orientation compared to nonpolar mpm. dem simulations show less material dilation than observed during experiments.

A semi-empirical model for the complete orientation dependence of the growth rate for vapor phase epitaxy - Chloride VPE of GaAs

NASA Technical Reports Server (NTRS)

Seidel-Salinas, L. K.; Jones, S. H.; Duva, J. M.

1992-01-01

A semi-empirical model has been developed to determine the complete crystallographic orientation dependence of the growth rate for vapor phase epitaxy (VPE). Previous researchers have been able to determine this dependence for a limited range of orientations; however, our model yields relative growth rate information for any orientation. This model for diamond and zincblende structure materials is based on experimental growth rate data, gas phase diffusion, and surface reactions. Data for GaAs chloride VPE is used to illustrate the model. The resulting growth rate polar diagrams are used in conjunction with Wulff constructions to simulate epitaxial layer shapes as grown on patterned substrates. In general, this model can be applied to a variety of materials and vapor phase epitaxy systems.

Fatigue tests of YBCO coated conductors

NASA Astrophysics Data System (ADS)

Bamba, S.; Tanaka, Y.; Ando, T.; Ueda, H.; Ishiyama, A.; Yamada, Y.; Shiohara, Y.

2008-02-01

In this paper, we report the fatigue characteristics of IBAD/PLD YBCO coated conductors. A YBCO coated conductor used in the superconducting coil of a SMES system is repeatedly subjected to mechanical tensile or compressive strain due to the Lorentz force during electrical charging or discharging. The superconducting characteristic of this conductor may deteriorate because of this cyclic strain. Therefore, it is necessary to investigate the effect of cyclic strain on the superconducting characteristics of YBCO coated conductors that have a laminated structure. We developed an experimental apparatus with a U-shaped sample holder in order to apply cyclic strain to the sample tape. This apparatus was used to perform the fatigue tests on YBCO coated conductors in liquid nitrogen in the absence of an external magnetic field. The strain cycles with the maximum strain epsilonmax (zero external strain → epsilonmax → zero external strain) were applied and repeated up to 5000 times, and the Ic measurements were performed at epsilonmax. Therefore, the application of cyclic strain with epsilonmax ranging from 0.3% to 0.5% did not result in any significant deterioration of the superconducting characteristics of the conductor.

Hydroxyapatite coating on PEEK implants: biomechanical and histological study in a rabbit model

PubMed Central

Durham, John W.; Montelongo, Sergio A.; Ong, Joo L.; Guda, Teja; Allen, Matthew J.; Rabiei, Afsaneh

2016-01-01

A bioactive two-layer coating consisting of hydroxyapatite (HA) and yttria-stabilized zirconia (YSZ) was investigated on cylindrical polyether ether ketone (PEEK) implants using ion beam assisted deposition (IBAD). Post-deposition heat treatments via variable frequency microwave annealing with and without subsequent autoclaving were used to crystallize the as-deposited amorphous HA layer. Microstructural analysis, performed by TEM and EDS, showed that these methods were capable of crystallizing HA coating on PEEK. The in vivo response to cylindrical PEEK samples with and without coating was studied by implanting uncoated PEEK and coated PEEK implants in the lateral femoral condyle of 18 rabbits. Animals were studied in two groups 9 for observation at 6 or 18 weeks post surgery. MicroCT analysis, histology, and mechanical pull-out tests were performed to determine the effect of the coating on osseointegration. The heat-treated HA/YSZ coatings showed improved implant fixation as well as higher bone regeneration and bone-implant contact area compared to uncoated PEEK. The study offers a novel method to coat PEEK implants with improved osseointegration. PMID:27524073

Hydroxyapatite coating on PEEK implants: Biomechanical and histological study in a rabbit model.

PubMed

Durham, John W; Montelongo, Sergio A; Ong, Joo L; Guda, Teja; Allen, Matthew J; Rabiei, Afsaneh

2016-11-01

A bioactive two-layer coating consisting of hydroxyapatite (HA) and yttria-stabilized zirconia (YSZ) was investigated on cylindrical polyetheretherketone (PEEK) implants using ion beam assisted deposition (IBAD). Post-deposition heat treatments via variable frequency microwave annealing with and without subsequent autoclaving were used to crystallize the as-deposited amorphous HA layer. Microstructural analysis, performed by TEM and EDS, showed that these methods were capable of crystallizing HA coating on PEEK. The in vivo response to cylindrical PEEK samples with and without coating was studied by implanting uncoated PEEK and coated PEEK implants in the lateral femoral condyle of 18 rabbits. Animals were studied in two groups of 9 for observation at 6 or 18weeks post surgery. Micro-CT analysis, histology, and mechanical pull-out tests were performed to determine the effect of the coating on osseointegration. The heat-treated HA/YSZ coatings showed improved implant fixation as well as higher bone regeneration and bone-implant contact area compared to uncoated PEEK. The study offers a novel method to coat PEEK implants with improved osseointegration. Copyright © 2016 Elsevier B.V. All rights reserved.

On the Life Orientations of the Young People of the Volga Region

ERIC Educational Resources Information Center

Iavon, S. V.

2011-01-01

Social and economic transformations in Russia have had an influence on all spheres of society. The value orientations of young people have been influenced by the market economy, and this has led to a new type of adaptive behavior, in which preference is given to material value orientations, growth of individualism, pragmatism, and hedonistic…

Improved Sectional Image Analysis Technique for Evaluating Fiber Orientations in Fiber-Reinforced Cement-Based Materials.

PubMed

Lee, Bang Yeon; Kang, Su-Tae; Yun, Hae-Bum; Kim, Yun Yong

2016-01-12

The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fiber-reinforced concrete. A series of tests on the accuracy of fiber detection and the estimation performance of fiber orientation was performed on artificial fiber images to assess the validity of the proposed technique. The validation test results showed that the proposed technique estimates the distribution of fiber orientation more accurately than the direct measurement of fiber orientation by image analysis.

Improved Sectional Image Analysis Technique for Evaluating Fiber Orientations in Fiber-Reinforced Cement-Based Materials

PubMed Central

Lee, Bang Yeon; Kang, Su-Tae; Yun, Hae-Bum; Kim, Yun Yong

2016-01-01

The distribution of fiber orientation is an important factor in determining the mechanical properties of fiber-reinforced concrete. This study proposes a new image analysis technique for improving the evaluation accuracy of fiber orientation distribution in the sectional image of fiber-reinforced concrete. A series of tests on the accuracy of fiber detection and the estimation performance of fiber orientation was performed on artificial fiber images to assess the validity of the proposed technique. The validation test results showed that the proposed technique estimates the distribution of fiber orientation more accurately than the direct measurement of fiber orientation by image analysis. PMID:28787839

Spall behaviour of single crystal aluminium at three principal orientations

NASA Astrophysics Data System (ADS)

Owen, G. D.; Chapman, D. J.; Whiteman, G.; Stirk, S. M.; Millett, J. C. F.; Johnson, S.

2017-10-01

A series of plate impact experiments have been conducted to study the spall strength of the three principal crystallographic orientations of single crystal aluminium ([100], [110] and, [111]) and ultra-pure polycrystalline aluminium. The samples have been shock loaded at two impact stresses (4 GPa and 10 GPa). Significant differences have been observed in the elastic behaviour, the pullback velocities, and the general shape of the wave profiles, which can be accounted for by considerations of the microscale homogeneity, the dislocation density, and the absence of grain boundaries in the single crystal materials. The data have shown that there is a consistent order of spall strength measured for the four sample materials. The [111] orientation has the largest spall strength and elastic limit, followed closely by [110], [100], and then the polycrystalline material. This order is consistent with both quasi-static data and geometrical consideration of Schmid factors.

Causes and Solutions for High Energy Consumption in Traditional Buildings Located in Hot Climate Regions

NASA Astrophysics Data System (ADS)

Barayan, Olfat Mohammad

A considerable amount of money for high-energy consumption is spent in traditional buildings located in hot climate regions. High-energy consumption is significantly influenced by several causes, including building materials, orientation, mass, and openings' sizes. This paper aims to identify these causes and find practical solutions to reduce the annual cost of bills. For the purpose of this study, simulation research method has been followed. A comparison between two Revit models has also been created to point out the major cause of high-energy consumption. By analysing different orientations, wall insulation, and window glazing and applying some other high performance building techniques, a conclusion was found to confirm that appropriate building materials play a vital role in affecting energy cost. Therefore, the ability to reduce the energy cost by more than 50% in traditional buildings depends on a careful balance of building materials, mass, orientation, and type of window glazing.

Self-shaping composites with programmable bioinspired microstructures.

PubMed

Erb, Randall M; Sander, Jonathan S; Grisch, Roman; Studart, André R

2013-01-01

Shape change is a prevalent function apparent in a diverse set of natural structures, including seed dispersal units, climbing plants and carnivorous plants. Many of these natural materials change shape by using cellulose microfibrils at specific orientations to anisotropically restrict the swelling/shrinkage of their organic matrices upon external stimuli. This is in contrast to the material-specific mechanisms found in synthetic shape-memory systems. Here we propose a robust and universal method to replicate this unusual shape-changing mechanism of natural systems in artificial bioinspired composites. The technique is based upon the remote control of the orientation of reinforcing inorganic particles within the composite using a weak external magnetic field. Combining this reinforcement orientational control with swellable/shrinkable polymer matrices enables the creation of composites whose shape change can be programmed into the material's microstructure rather than externally imposed. Such bioinspired approach can generate composites with unusual reversibility, twisting effects and site-specific programmable shape changes.

Friction Anisotropy with Respect to Topographic Orientation

PubMed Central

Yu, Chengjiao; Wang, Q. Jane

2012-01-01

Friction characteristics with respect to surface topographic orientation were investigated using surfaces of different materials and fabricated with grooves of different scales. Scratching friction tests were conducted using a nano-indentation-scratching system with the tip motion parallel or perpendicular to the groove orientation. Similar friction anisotropy trends were observed for all the surfaces studied, which are (1) under a light load and for surfaces with narrow grooves, the tip motion parallel to the grooves offers higher friction coefficients than does that perpendicular to them, (2) otherwise, equal or lower friction coefficients are found under this motion. The influences of groove size relative to the diameter of the mating tip (as a representative asperity), surface contact stiffness, contact area, and the characteristic stiction length are discussed. The appearance of this friction anisotropy is independent of material; however, the boundary and the point of trend transition depend on material properties. PMID:23248751

Material orientation design of planar structures with prescribed anisotropy classes. Study of rhombic systems

NASA Astrophysics Data System (ADS)

Czubacki, Radosław

2018-01-01

The paper deals with the minimum compliance problem of 2D structures made of a non-homogeneous elastic material. In the first part of the paper a comparison between solutions of Free Material Design (FMD), Cubic Material Design (CMD) and Isotropic Material Design (IMD) is shown for a simply supported plate in a shape of a deep beam, subjected to a concentrated in-plane force at its upper face. The isoperimetric condition fixes the value of the cost of the design expressed as the integral of the trace of the Hooke tensor. In the second part of the paper the material design approaches are extended to rhombic system in 2D. For the rhombic system the material properties of the structures are set, the design variables being the trajectories of anisotropy directions which in 2D are described by one parameter. In the Orthotropic Orientation Design (OOD) no isoperimetric condition is used.

Breakthrough and future: nanoscale controls of compositions, morphologies, and mesochannel orientations toward advanced mesoporous materials.

PubMed

Yamauchi, Yusuke; Suzuki, Norihiro; Radhakrishnan, Logudurai; Wang, Liang

2009-01-01

Currently, ordered mesoporous materials prepared through the self-assembly of surfactants have attracted growing interests owing to their special properties, including uniform mesopores and a high specific surface area. Here we focus on fine controls of compositions, morphologies, mesochannel orientations which are important factors for design of mesoporous materials with new functionalities. This Review describes our recent progress toward advanced mesoporous materials. Mesoporous materials now include a variety of inorganic-based materials, for example, transition-metal oxides, carbons, inorganic-organic hybrid materials, polymers, and even metals. Mesoporous metals with metallic frameworks can be produced by using surfactant-based synthesis with electrochemical methods. Owing to their metallic frameworks, mesoporous metals with high electroconductivity and high surface areas hold promise for a wide range of potential applications, such as electronic devices, magnetic recording media, and metal catalysts. Fabrication of mesoporous materials with controllable morphologies is also one of the main subjects in this rapidly developing research field. Mesoporous materials in the form of films, spheres, fibers, and tubes have been obtained by various synthetic processes such as evaporation-mediated direct templating (EDIT), spray-dried techniques, and collaboration with hard-templates such as porous anodic alumina and polymer membranes. Furthermore, we have developed several approaches for orientation controls of 1D mesochannels. The macroscopic-scale controls of mesochannels are important for innovative applications such as molecular-scale devices and electrodes with enhanced diffusions of guest species. Copyright 2009 The Japan Chemical Journal Forum and Wiley Periodicals, Inc.

Microstructure and Mechanics of Superconductor Epitaxy via the Chemical Solution Deposition Method

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

Frederick F. Lange

2006-11-30

Executive Summary: Initially the funds were sufficient funds were awarded to support one graduate student and one post-doc. Lange, though other funds, also supported a graduate intern from ETH Zurich, Switzerland for a period of 6 months. The initial direction was to study the chemical solution deposition method to understand the microstructural and mechanical phenomena that currently limit the production of thick film, reliable superconductor wires. The study was focused on producing thicker buffer layer(s) on Ni-alloy substrates produced by the RABiTS method. It focused on the development of the microstructure during epitaxy, and the mechanical phenomena that produce cracksmore » during dip-coating, pyrolysis (decomposition of precursors during heating), crystallization and epitaxy. The initial direction of producing thicker layers of a know buffer layer material was redirected by co-workers at ORNL, in an attempt to epitaxially synthesize a potential buffer layer material, LaMnO3, via the solution route. After a more than a period of 6 months that showed that the LaMnO3 reacted with the Ni-W substrate at temperatures that could produce epitaxy, reviewers at the annual program review strongly recommended that the research was not yielding positive results. The only positive result presented at the meeting was that much thicker films could be produce by incorporating a polymer into the precursor that appeared to increase the precursor’s resistance to crack growth. Thus, to continue the program, the objectives were changed to find compositions with the perovskite structure that would be a) chemically compatible with either the Ni-W RABiTS or the MgO IBAD Ni-alloy substrates, and produce a better lattice parameter fit between either of the two substrates. At the start of the second year, the funding was reduced to 2/3’s of the first year level, which required the termination of the post-doc after approximately 5 months into the second year. From then on, further funding was intermittent to say the least, and funding to support the student and the research expenses has to be supplemented by Lange’s gift funds. During the first part of the second year, strontium zirconate was identified as an alternative to lanthanum manganite as a buffer layer for use on the IBAD MgO superconducting wire. A lattice parameter of 4.101 Angstroms offers a reduced lattice mismatch between the MgO and SrZrO3. Studies were focused on investigating hybrid precursor routes, combining Sr acetate with a number of different Zr alkoxides. Initial results from heat treating precursors to form powders are positive with the formation of orthorhombic SrZrO3 at temperatures between 800°C and 1100°C under a reducing atmosphere of Ar – 5% H2. Buffer layer research on RABiTS substrates were centered on GdAlO3 (3.71 Å) and YAlO3 (3.68 Å) buffer layer materials. Powder experiments in YAlO3 have shown the perovskite phase to be metastable at processing temperatures below 1500 °C. Experiments involving spin coating of YAlO3 precursors have found significant problems involved with wettability of the YAlO3 precursor (Yttrium acetate, Aluminum tri-sec butoxide, DI water and Formic Acid) on RABiTS substrates; this, and the demise of the funds precluded further research using YAlO3. The diminished funds for the second year, and the small, tricked funds during the third year lead to a redirection of the student to another research area., and a stop to any experimental achievements that were much too ambition relative to the available funds. The only positive results obtained during this latter period was the understanding why two dissimilar structures could result in an epitaxial relation. It was shown that two rules of crystal chemistry, cation/anion coordination and charge balance, could be applied to understand the epitaxy of SrTiO3 on Ni c(2 X 2)S, TiO2 (anatase) on LaAlO3, TiO2 (rutile) on r-plane Al2O3, and Zr1-x(Yx)O2 on (0001) Al2O3. This new understanding of the interface between two dissimilar structures has important implications that include the buffer layers used for the superconductor program, namely, the epitaxy of perovskites such as the epitaxy of SrTiO3 on the Ni c(2 X 2)S wire. This discovery is the major part of the finial report that follows.« less

14 CFR § 1213.108 - Multimedia materials.

Code of Federal Regulations, 2014 CFR

2014-01-01

... NEWS AND INFORMATION MEDIA § 1213.108 Multimedia materials. (a) NASA's multimedia material, from all... original or duplicate files of news-oriented imagery and other digital multimedia material generated within... the opinion of the installations, would be appropriate for use as news feed material or features in...

Vocational Career Orientation Guide. Arkansas Guidebook for Career Orientation. 7th-8th-9th Grades. Revised.

ERIC Educational Resources Information Center

Arkansas State Univ., State University.

This curriculum package contains materials for teaching the career orientation course in the junior high schools of Arkansas. Following the introduction, which describes the course and provides a rationale for it, along with instructions to teachers for conducting the course, the package is divided into 35 units organized under five major…

Formation of Cu-type shear bands and their influence on deformation and texture of rolled f.c.c. {l_brace}112{r_brace}<111> single crystals

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

Wagner, P.; Engler, O.; Luecke, K.

1995-10-01

Microstructural and textural evolution during rolling were investigated in (112)[11{bar 1}] single crystals of Al, Cu, and homogeneous supersaturated Al1.8wt%Cu. After a rolling degree of 30% the initial C-orientation (112)[11{bar 1}] of all three materials has rotated towards the so called D-orientation (4411)[1111{bar 8}]. While in the non-shear banding Al the D-orientation remains stable up to high rolling degrees, in the shear banding materials Cu and Al-Cu it rotates back to the initial C-orientation simultaneously with the formation of shear bands. This orientation change is explained by a rigid body rotation due to the special geometry of a deformation withmore » unidirectional shear bands. With the onset of shear band formation also strong orientation scatterings about the transverse direction appear in the pole figures. These scatterings are located inside the shear bands as well as their vicinity. They are due to the strong shear deformation and the resulting reaction stresses occurring in the shear bands and in their vicinity, respectively.« less

Molecularly Oriented Polymeric Thin Films for Space Applications

NASA Technical Reports Server (NTRS)

Fay, Catharine C.; Stoakley, Diane M.; St.Clair, Anne K.

1997-01-01

The increased commitment from NASA and private industry to the exploration of outer space and the use of orbital instrumentation to monitor the earth has focused attention on organic polymeric materials for a variety of applications in space. Some polymeric materials have exhibited short-term (3-5 yr) space environmental durability; however, future spacecraft are being designed with lifetimes projected to be 10-30 years. This gives rise to concern that material property change brought about during operation may result in unpredicted spacecraft performance. Because of their inherent toughness and flexibility, low density, thermal stability, radiation resistance and mechanical strength, aromatic polyimides have excellent potential use as advanced materials on large space structures. Also, there exists a need for high temperature (200-300 C) stable, flexible polymeric films that have high optical transparency in the 300-600nm range of the electromagnetic spectrum. Polymers suitable for these space applications were fabricated and characterized. Additionally, these polymers were molecularly oriented to further enhance their dimensional stability, stiffness, elongation and strength. Both unoriented and oriented polymeric thin films were also cryogenically treated to temperatures below -184 C to show their stability in cold environments and determine any changes in material properties.

Energy distribution in disordered elastic networks

NASA Astrophysics Data System (ADS)

Plaza, Gustavo R.

2010-09-01

Disordered networks are found in many natural and artificial materials, from gels or cytoskeletal structures to metallic foams or bones. Here, the energy distribution in this type of networks is modeled, taking into account the orientation of the struts. A correlation between the orientation and the energy per unit volume is found and described as a function of the connectivity in the network and the relative bending stiffness of the struts. If one or both parameters have relatively large values, the struts aligned in the loading direction present the highest values of energy. On the contrary, if these have relatively small values, the highest values of energy can be reached in the struts oriented transversally. This result allows explaining in a simple way remodeling processes in biological materials, for example, the remodeling of trabecular bone and the reorganization in the cytoskeleton. Additionally, the correlation between the orientation, the affinity, and the bending-stretching ratio in the network is discussed.

Orientation of Vanadium Dioxide Grains on Various Substrates

NASA Astrophysics Data System (ADS)

Rivera, Felipe; Davis, Robert; Vanfleet, Richard

2010-10-01

Crystalline vanadium dioxide VO2 experiences a fast and reversible semiconductor-to-metal structural phase transition near 68^oC. The changes exhibited during this phase transition comprise a well known change in resistivity of several orders of magnitude, as well as a significant drop in optical transmittance in the infrared. Due to the changes in these optical and electronic properties, vanadium dioxide shows promise as a material to be used in many applications ranging from thermochromic window coatings to optoelectronic devices. However, since there is a structural component to the phase transition of VO2, it is of interest to study the orientation of the crystalline grains deposited. Substrates such as glass, SiO2, Sapphire, and TiO2 have been used for the deposition of this material. We used orientation imaging microscopy to study and characterize the orientation of the grains deposited on several of these substrates. Here we present results on this study.

Fiber Orientation Effects in Fused Filament Fabrication of Air-Cooled Heat Exchangers

NASA Astrophysics Data System (ADS)

Mulholland, T.; Goris, S.; Boxleitner, J.; Osswald, T. A.; Rudolph, N.

2018-03-01

Fused filament fabrication (FFF) is a type of additive manufacturing based on material extrusion that has long been considered a prototyping technology. However, the right application of material, process, and product can be used for manufacturing of end-use products, such as air-cooled heat exchangers made by adding fillers to the base polymer, enhancing the thermal conductivity. Fiber fillers lead to anisotropic thermal conductivity, which is governed by the process-induced fiber orientation. This article presents an experimental study on the microstructure-property relationship for carbon fiber-filled polyamide used in FFF. The fiber orientation is measured by micro-computed tomography, and the thermal conductivity of manufactured samples is measured. Although the thermal conductivity is raised by more than three times in the fiber orientation direction at a load of only 12 vol.%, the enhancement is low in the other directions, and this anisotropy, along with certain manufacturing restrictions, influences the final part performance.

Tailorable Dielectric Material with Complex Permittivity Characteristics

NASA Technical Reports Server (NTRS)

Smith, Joseph G. (Inventor); Watson, Kent A. (Inventor); Elliott, Holly A (Inventor); Delozier, Donavon Mark (Inventor); Connell, John W. (Inventor); Ghose, Sayata (Inventor); Dudley, Kenneth L. (Inventor)

2014-01-01

A dielectric material includes a network of nanosubstrates, such as but not limited to nanotubes, nanosheets, or other nanomaterials or nanostructures, a polymer base material or matrix, and nanoparticles constructed at least partially of an elemental metal. The network has a predetermined nanosubstrate loading percentage by weight with respect to a total weight of the dielectric material, and a preferential or predetermined longitudinal alignment with respect to an orientation of an incident electrical field. A method of forming the dielectric material includes depositing the metal-based nanoparticles onto the nanosubstrates and subsequently mixing these with a polymer matrix. Once mixed, alignment can be achieved by melt extrusion or a similar mechanical shearing process. Alignment of the nanosubstrate may be in horizontal or vertical direction with respect to the orientation of an incident electrical field.

Modeling the effect of orientation on the shock response of a damageable composite material

NASA Astrophysics Data System (ADS)

Lukyanov, Alexander A.

2012-10-01

A carbon fiber-epoxy composite (CFEC) shock response in the through thickness orientation and in one of the fiber directions is significantly different. The hydrostatic pressure inside anisotropic materials depends on deviatoric strain components as well as volumetric strain. Non-linear effects, such as shock effects, can be incorporated through the volumetric straining in the material. Thus, a new basis is required to couple the anisotropic material stiffness and strength with anisotropic shock effects, associated energy dependence, and damage softening process. This article presents these constitutive equations for shock wave modeling of a damageable carbon fiber-epoxy composite. Modeling the effect of fiber orientation on the shock response of a CFEC has been performed using a generalized decomposition of the stress tensor [A. A. Lukyanov, Int. J. Plast. 24, 140 (2008)] and Mie-Grüneisen's extrapolation of high-pressure shock Hugoniot states to other thermodynamics states for shocked CFEC materials. The three-wave structure (non-linear anisotropic, fracture, and isotropic elastic waves) that accompanies damage softening process is also proposed in this work for describing CFEC behavior under shock loading which allows to remove any discontinuities observed in the linear case for relation between shock velocities and particle velocities [A. A. Lukyanov, Eur. Phys. J. B 74, 35 (2010)]. Different Hugoniot stress levels are obtained when the material is impacted in different directions; their good agreement with the experiment demonstrates that the anisotropic equation of state, strength, and damage model are adequate for the simulation of shock wave propagation within damageable CFEC material. Remarkably, in the through thickness orientation, the material behaves similar to a simple polymer whereas in the fiber direction, the proposed in this paper model explains an initial ramp, before at sufficiently high stresses, and a much faster rising shock above it. The numerical results for shock wave modeling using proposed constitutive equations are presented, discussed, and future studies are outlined.

Hyperelastic remodeling in the intrauterine growth restricted (IUGR) carotid artery in the near-term fetus

PubMed Central

Dodson, R. Blair; Rozance, Paul J.; Reina-Romo, Esther; Ferguson, Virginia L.; Hunter, Kendall S.

2013-01-01

A constitutive model for a fiber reinforced hyperelastic material was applied to understand arterial fiber remodeling in a sheep model of Intrauterine Growth Restriction (IUGR). IUGR is associated altered hemodynamics characterized by increased resistance to blood flow in the placenta and elevated fetal arterial pressure and pulsatility. The constitutive model describes the collagen contribution to the mechanics within the arterial wall in both control and IUGR carotid artery through defining the material modulus and the orientation of the microstructure. A sheep model of placental insufficiency induced IUGR (PI-IUGR) was created by exposure of the pregnant ewe to elevated ambient temperatures. Experimental data was collected using pressure–diameter measurements to measure passive compliance in control and PI-IUGR carotid arteries. The constitutive model was optimized to fit the experimental data predicting the material parameters. Specifically, the collagen fiber predicted angle (γ) in the control artery was 49.9° from the circumferential axis while the PI-IUGR was 16.6° with a 23.5% increase in fiber orientation (κ). Quantitative assessment of collagen fiber orientation in secondary harmonic generation images confirmed the shift in orientation between the two groups. Together these suggest vascular remodeling of the ECM fiber orientation plays a major role in arterial stiffening in the PI-IUGR near-term fetal sheep. PMID:23332229

Facile Fabrication of Electrically Conductive Low-Density Polyethylene/Carbon Fiber Tubes for Novel Smart Materials via Multiaxial Orientation.

PubMed

Li, Yijun; Nie, Min; Wang, Qi

2018-01-10

Electromechanical sensors are indispensable components in functional devices and robotics application. However, the fabrication of the sensors still maintains a challenging issue that high percolation threshold and easy failure of conductive network are derived from uniaxial orientation of conductive fillers in practical melt processing. Herein, we reported a facile fabrication method to prepare a multiaxial low-density polyethylene (LDPE)/carbon fibers (CFs) tube with bidirectional controllable electrical conductivity and sensitive strain-responsive performance via rotation extrusion technology. The multidimensional helical flow is confirmed in the reverse rotation extrusion, and the CFs readily respond to the flow field leading to a multiaxial orientation in the LDPE matrix. In contrast to uniaxial LDPE/CF composites, which perform a "head to head" conjunction, multiaxial-orientated CF networks exhibit a unique multilayer structure in which the CFs with distinct orientation direction intersect in the interface, endowing the LDPE/CF composites with a low percolation threshold (15 wt %) to those of the uniaxial ones (∼35 wt %). The angles between two axes play a vital role in determining the density of the conductive networks in the interface, which is predominant in tuning the bending-responsive behaviors with a gauge factor range from 12.5 to 56.3 and the corresponding linear respond region from ∼15 to ∼1%. Such a superior performance of conductive LDPE/CF tube confirms that the design of multiaxial orientation paves a novel way to facile fabrication of advanced cost-effective CF-based smart materials, shedding light on promising applications such as smart materials and intelligent engineering monitoring.

The effect of alkaline treatment and fiber orientation on impact resistant of bio-composites Sansevieria trifasciata fiber/polypropylene as automotive components material

NASA Astrophysics Data System (ADS)

Shieddieque, Apang Djafar; Mardiyati, Suratman, Rochim; Widyanto, Bambang

2018-04-01

The increasing amount of car usage is causing an escalated amount of fuel consumption and CO2 emission. It implicates demand for the automotive industry to increase the efficiency of their products, One of the most effective ways to solve the issue is to find green weight light material for the interior automotive component. The Aim of this research was to investigate the effect of alkaline treatment and fiber orientation on the impact resistant of material bio- composite sansevieiria trifasciata fiber/Polypropylene. In this research, bio-composites sansevieria trifasciata fiber/Polypropylene was prepared with random fiber orientation and unidirectional orientation by using a hot press method with pressure 140 Bar and temperature 240°C. Fiber was taken from Sansevieria trifasciata by using mechanical retting. In this study, Sansevieria fiber was given alkaline treatment (mercerization) with NaOH 3% (w/w) solution at temperature 100°C for an hour. The fraction of fiber volume that were used in this experiment are 0%, 5%, 10%, and 15%. The impact test was conducted based on ASTM D 6110 - 04, and the fracture analysis was investigated by scanning electron microscope (SEM). The best result of impact toughness and fracture analysis were achieved by bio composite untreated and unidirectional sansevieria trifasciata fiber/Polypropylene with fiber volume fraction of 15%, which was 48.092kJ/m2 for impact resistant. As compared to the impact toughness standard, which needed for interior automotive component, the impact toughness of sansevieria trifasciata fiber/Polypropylene has fulfilled the standard of the interior material automotive industry. Therefore, this material can be potentially used as materials on the car exterior component.

Architecture for coated conductors

DOEpatents

Foltyn, Stephen R.; Arendt, Paul N.; Wang, Haiyan; Stan, Liliana

2010-06-01

Articles are provided including a base substrate having a layer of an oriented cubic oxide material with a rock-salt-like structure layer thereon, and, a layer of epitaxial titanium nitride upon the layer of an oriented cubic oxide material having a rock-salt-like structure. Such articles can further include thin films of high temperature superconductive oxides such as YBCO upon the layer of epitaxial titanium nitride or upon a intermediate buffer layer upon the layer of epitaxial titanium nitride.

Evaluation criteria for commercially oriented materials processing in space proposals

NASA Technical Reports Server (NTRS)

Moore, W. F.; Mcdowell, J. R.

1979-01-01

An approach and criteria for evaluating NASA funded experiments and demonstrations which have commercial potential were developed. Methods for insuring quick initial screening of commercial proposals are presented. Recommendations are given for modifying the current evaluation approach. New criteria for evaluating commercially orientated materials processing in space (MPS) proposals are introduced. The process for selection of qualified individuals to evaluate the phases of this approach and criteria is considered and guidelines are set for its implementation.

Making High-Temperature Superconductors By Melt Sintering

NASA Technical Reports Server (NTRS)

Golben, John P.

1992-01-01

Melt-sintering technique applied to YBa2Cu3O7-x system and to Bi/Ca/Sr/Cu-oxide system to produce highly oriented bulk high-temperature-superconductor materials extending to macroscopically usable dimensions. Processing requires relatively inexpensive and simple equipment. Because critical current two orders of magnitude greater in crystal ab plane than in crystal c direction, high degree of orientation greatly enhances critical current in these bulk materials, making them more suitable for many proposed applications.

Giant piezoelectric voltage coefficient in grain-oriented modified PbTiO 3 material

DOE PAGES

Yan, Yongke; Zhou, Jie E.; Maurya, Deepam; ...

2016-10-11

A rapid surge in the research on piezoelectric sensors is occurring with the arrival of the Internet of Things. Single-phase oxide piezoelectric materials with giant piezoelectric voltage coefficient (g, induced voltage under applied stress) and high Curie temperature (T c) are crucial towards providing desired performance for sensing, especially under harsh environmental conditions. Here, we report a grain-oriented (with 95% <001> texture) modified PbTiO 3 ceramic that has a high T c (364°C) and an extremely large g 33 (115 × 10 -3 Vm N -1) in comparison with other known single-phase oxide materials. Our results reveal that self-polarization duemore » to grain orientation along the spontaneous polarization direction plays an important role in achieving large piezoelectric response in a domain motion-confined material. Finally, the phase field simulations confirm that the large piezoelectric voltage coefficient g 33 originates from maximized piezoelectric strain coefficient d 33 and minimized dielectric permittivity ε 33 in [001]-textured PbTiO 3 ceramics where domain wall motions are absent.« less

Giant piezoelectric voltage coefficient in grain-oriented modified PbTiO3 material

PubMed Central

Yan, Yongke; Zhou, Jie E.; Maurya, Deepam; Wang, Yu U.; Priya, Shashank

2016-01-01

A rapid surge in the research on piezoelectric sensors is occurring with the arrival of the Internet of Things. Single-phase oxide piezoelectric materials with giant piezoelectric voltage coefficient (g, induced voltage under applied stress) and high Curie temperature (Tc) are crucial towards providing desired performance for sensing, especially under harsh environmental conditions. Here, we report a grain-oriented (with 95% <001> texture) modified PbTiO3 ceramic that has a high Tc (364 °C) and an extremely large g33 (115 × 10−3 Vm N−1) in comparison with other known single-phase oxide materials. Our results reveal that self-polarization due to grain orientation along the spontaneous polarization direction plays an important role in achieving large piezoelectric response in a domain motion-confined material. The phase field simulations confirm that the large piezoelectric voltage coefficient g33 originates from maximized piezoelectric strain coefficient d33 and minimized dielectric permittivity ɛ33 in [001]-textured PbTiO3 ceramics where domain wall motions are absent. PMID:27725634

Flexible Composite-Material Pressure Vessel

NASA Technical Reports Server (NTRS)

Brown, Glen; Haggard, Roy; Harris, Paul A.

2003-01-01

A proposed lightweight pressure vessel would be made of a composite of high-tenacity continuous fibers and a flexible matrix material. The flexibility of this pressure vessel would render it (1) compactly stowable for transport and (2) more able to withstand impacts, relative to lightweight pressure vessels made of rigid composite materials. The vessel would be designed as a structural shell wherein the fibers would be predominantly bias-oriented, the orientations being optimized to make the fibers bear the tensile loads in the structure. Such efficient use of tension-bearing fibers would minimize or eliminate the need for stitching and fill (weft) fibers for strength. The vessel could be fabricated by techniques adapted from filament winding of prior composite-material vessels, perhaps in conjunction with the use of dry film adhesives. In addition to the high-bias main-body substructure described above, the vessel would include a low-bias end substructure to complete coverage and react peak loads. Axial elements would be overlaid to contain damage and to control fiber orientation around side openings. Fiber ring structures would be used as interfaces for connection to ancillary hardware.

Optimal configuration of microstructure in ferroelectric materials by stochastic optimization

NASA Astrophysics Data System (ADS)

Jayachandran, K. P.; Guedes, J. M.; Rodrigues, H. C.

2010-07-01

An optimization procedure determining the ideal configuration at the microstructural level of ferroelectric (FE) materials is applied to maximize piezoelectricity. Piezoelectricity in ceramic FEs differs significantly from that of single crystals because of the presence of crystallites (grains) possessing crystallographic axes aligned imperfectly. The piezoelectric properties of a polycrystalline (ceramic) FE is inextricably related to the grain orientation distribution (texture). The set of combination of variables, known as solution space, which dictates the texture of a ceramic is unlimited and hence the choice of the optimal solution which maximizes the piezoelectricity is complicated. Thus, a stochastic global optimization combined with homogenization is employed for the identification of the optimal granular configuration of the FE ceramic microstructure with optimum piezoelectric properties. The macroscopic equilibrium piezoelectric properties of polycrystalline FE is calculated using mathematical homogenization at each iteration step. The configuration of grains characterized by its orientations at each iteration is generated using a randomly selected set of orientation distribution parameters. The optimization procedure applied to the single crystalline phase compares well with the experimental data. Apparent enhancement of piezoelectric coefficient d33 is observed in an optimally oriented BaTiO3 single crystal. Based on the good agreement of results with the published data in single crystals, we proceed to apply the methodology in polycrystals. A configuration of crystallites, simultaneously constraining the orientation distribution of the c-axis (polar axis) while incorporating ab-plane randomness, which would multiply the overall piezoelectricity in ceramic BaTiO3 is also identified. The orientation distribution of the c-axes is found to be a narrow Gaussian distribution centered around 45°. The piezoelectric coefficient in such a ceramic is found to be nearly three times as that of the single crystal. Our optimization model provide designs for materials with enhanced piezoelectric performance, which would stimulate further studies involving materials possessing higher spontaneous polarization.

A direct correlation of x-ray diffraction orientation distributions to the in-plane stiffness of semi-crystalline organic semiconducting films

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

Zhao, Bingxiao; Awartani, Omar; O'Connor, Brendan

2016-05-02

Large charge mobilities of semi-crystalline organic semiconducting films could be obtained by mechanically aligning the material phases of the film with the loading axis. A key element is to utilize the inherent stiffness of the material for optimal or desired alignment. However, experimentally determining the moduli of semi-crystalline organic thin films for different loading directions is difficult, if not impossible, due to film thickness and material anisotropy. In this paper, we address these challenges by presenting an approach based on combining a composite mechanics stiffness orientation formulation with a Gaussian statistical distribution to directly estimate the in-plane stiffness (transverse isotropy)more » of aligned semi-crystalline polymer films based on crystalline orientation distributions obtained by X-ray diffraction experimentally at different applied strains. Our predicted results indicate that the in-plane stiffness of an annealing film was initially isotropic, and then it evolved to transverse isotropy with increasing mechanical strains. This study underscores the significance of accounting for the crystalline orientation distributions of the film to obtain an accurate understanding and prediction of the elastic anisotropy of semi-crystalline polymer films.« less

Evaluation of Curricula Content Based on Thai Pharmacy Competency Standards

PubMed Central

Maitreemit, Pagamas; Pongcharoensuk, Petcharat; Armstrong, Edward P.

2008-01-01

Objective To evaluate the curricula content of Thai pharmacy schools based on the Thai pharmacy competency standards. Methods Course syllabi were collected from 11 pharmacy schools. A questionnaire was developed based on the Thai pharmacy competency standards. Course coordinators completed the questionnaire assessing the curricula content. Results The curricula for both the bachelor of science in pharmacy degree (BS Pharm) and doctor of pharmacy (PharmD) degree programs included the minimum content required by the 8 competency domains. The dominant content area in BS Pharm degree programs was product-oriented material. The content ratio of patient to product to social and administrative pharmacy in the BS Pharm degree programs was 2:3:1, respectively. However, the content ratio suggested by the Thai Pharmacy Council was 3:2:1, respectively. For the PharmD programs, the largest content area was patient-oriented material, which was in agreement with the framework suggested by the Thai Pharmacy Council. Conclusions The curricula of all Thai pharmacy schools met the competency standards; however, some patient-oriented material should be expanded and some product-oriented content deleted in order to meet the recommended content ratio. PMID:18322571

Teacher's Guide to Occupational Orientation.

ERIC Educational Resources Information Center

National Evaluation Systems, Inc., Amherst, MA.

This guide is specifically designed to accompany materials developed for occupational orientation (particularly in Illinois) in the following five cluster areas: Applied biological and agricultural occupations; personal and public service occupations; health occupations; business, marketing, and management occupations; and industrial oriented…

Erosion Results of the MISSE 8 Polymers Experiment After 2 Years of Space Exposure on the International Space Station

NASA Technical Reports Server (NTRS)

de Groh, Kim K.; Banks, Bruce A.; Asmar, Olivia C.; Yi, Grace T.; Mitchell, Gianna G.; Guo, Aobo; Sechkar, Edward A.

2017-01-01

Polymers and other oxidizable materials on the exterior of spacecraft in the low Earth orbit (LEO) space environment can be eroded due to reaction with atomic oxygen (AO). Therefore, in order to design durable spacecraft, it is important to know the LEO AO erosion yield (E(sub y), volume loss per incident oxygen atom) of materials susceptible to AO reaction. A spaceflight experiment, called the Polymers Experiment, which contained 42 samples, was developed to determine the effect of solar exposure on the AO E(sub y) of fluoropolymers flown in ram, wake, or zenith orientations. The Polymers Experiment was exposed to the LEO space environment on the exterior of the International Space Station (ISS) as part of the Materials International Space Station Experiment 8 (MISSE 8) mission. The MISSE 8 mission included samples flown in a zenith/nadir orientation for 2.14 years in the MISSE 8 Passive Experiment Container (PEC), and samples flown in a ram/wake orientation for 2.0 years in the Optical Reflector Materials Experiment-III (ORMatEIII) tray. The experiment included Kapton H (Registered Trademark) witness samples for AO fluence determination in each orientation. This paper provides an overview of the MISSE 8 mission, a description of the flight experiment with details on the polymers flown, the characterization techniques used, the AO fluence for each exposure orientation, and the LEO E(sub y) results. The E(sub y) of Teflon fluorinated ethylene propylene (FEP) samples flown in ram, wake, and zenith orientations have been compared, and the E(sub y) was found to be highly dependent on orientation and therefore environmental exposure. The FEP E(sub y) was found to directly correlate with the solar exposure/AO fluence ratio showing the effect of solar radiation and/or heating due to solar exposure on FEP erosion. In addition, back-surface carbon painted FEP (C-FEP) flown in the zenith orientation had a significantly higher E(sub y) than clear FEP or Al-FEP further indicating that heating has a significant impact on the erosion of FEP. This experiment provides valuable LEO flight data on the erosion of Teflon FEP, a commonly used spacecraft thermal insulation.

Effects of void anisotropy on the ignition and growth rates of energetic materials

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Sen, Oishik; Udaykumar, H. S.

2017-06-01

Initiation of heterogeneous energetic materials is thought to occur at hot spots; reaction fronts propagate from sites of such hot spots into the surrounding material resulting in complete consumption of the material. Heterogeneous materials, such as plastic bonded explosives (PBXs) and pressed materials contain numerous voids, defects and interfaces at which hot spots can occur. Amongst the various mechanisms of hot spot formation, void collapse is considered to be the predominant one in the high strain rate loading conditions. It is established in the past the shape of the voids has a significant effect on the initiation behavior of energetic materials. In particular, void aspect ratio and orientations play an important role in this regard. This work aims to quantify the effects of void aspect ratio and orientation on the ignition and growth rates of chemical reaction from the hot spot. A wide range of aspect ratio and orientations is considered to establish a correlation between the ignition and growth rates and the void morphology. The ignition and growth rates are obtained from high fidelity reactive meso-scale simulations. The energetic material considered in this work is HMX and Tarver McGuire HMX decomposition model is considered to capture the reaction mechanism of HMX. The meso-scale simulations are performed using a Cartesian grid based Eulerian solver SCIMITAR3D. The void morphology is shown to have a significant effect on the ignition and growth rates of HMX.

Highly Polarized Fluorescent Illumination Using Liquid Crystal Phase.

PubMed

Gim, Min-Jun; Turlapati, Srikanth; Debnath, Somen; Rao, Nandiraju V S; Yoon, Dong Ki

2016-02-10

Liquid crystal (LC) materials are currently the dominant electronic materials in display technology because of the ease of control of molecular orientation using an electric field. However, this technology requires the fabrication of two polarizers to create operational displays, reducing light transmission efficiency below 10%. It is therefore desirable to develop new technologies to enhance the light efficiency while maintaining or improving other properties such as the modulation speed of the molecular orientation. Here we report a uniaxial-oriented B7 smectic liquid crystalline film, using fluorescent bent-core LC molecules, a chemically modified substrate, and an in-plane electric field. A LC droplet under homeotropic boundary conditions of air/LC as well as LC/substrate exhibits large focal conic like optical textures. The in-plane electric field induced uniaxial orientation of the LC molecules, in which molecular polar directors are aligned in the direction of the electric field. This highly oriented LC film exhibits linearly polarized luminescence and microsecond time-scale modulation characteristics. The resultant device is both cheap and easy to fabricate and thus has great potential for electro-optic applications, including LC displays, bioimaging systems, and optical communications.

Contactor/filter improvements

DOEpatents

Stelman, D.

1988-06-30

A contactor/filter arrangement for removing particulate contaminants from a gaseous stream is described. The filter includes a housing having a substantially vertically oriented granular material retention member with upstream and downstream faces, a substantially vertically oriented microporous gas filter element, wherein the retention member and the filter element are spaced apart to provide a zone for the passage of granular material therethrough. A gaseous stream containing particulate contaminants passes through the gas inlet means as well as through the upstream face of the granular material retention member, passing through the retention member, the body of granular material, the microporous gas filter element, exiting out of the gas outlet means. A cover screen isolates the filter element from contact with the moving granular bed. In one embodiment, the granular material is comprised of porous alumina impregnated with CuO, with the cover screen cleaned by the action of the moving granular material as well as by backflow pressure pulses. 6 figs.

Tensile Fracture of Ductile Materials. M.S. Thesis

NASA Technical Reports Server (NTRS)

Pai, D. M.

1984-01-01

For brittle materials, circular voids play an important role relative to fracture, intensifing both tensile and compressive stresses. A maximum intensified tensile stress failure criterion applies quite well to brittle materials. An attempt was made to explore the possibility of extending the approach to the tensile fracture of ductile materials. The three dimensional voids that exist in reality are modelled by circular holes in sheet metal. Mathematical relationships are sought between the shape and size of the hole, after the material is plastically deformed, and the amount of deformation induced. Then, the effect of hole shape, size and orientation on the mechanical properties is considered experimentally. The presence of the voids does not affect the ultimate tensile strength of the ductile materials because plastic flow wipes out the stress intensification caused by them. However, the shape and orientation of the defect is found to play an important role in affecting the strain at fracture.

Electromechanical properties of a textured ceramic material in the (1 - x)PMN- xPT system: Simulation based on the effective-medium method

NASA Astrophysics Data System (ADS)

Aleshin, V. I.; Raevskiĭ, I. P.; Sitalo, E. I.

2008-11-01

A complete set of dielectric, piezoelectric, and elastic parameters for the textured ceramic material 0.67PMN-0.33PT is calculated by the self-consistency method with due regard for the anisotropy and piezoelectric activity of the medium. It is shown that the best piezoelectric properties corresponding to those of a single crystal are observed for the ceramic material with a texture in which all crystallites are oriented parallel to the [001] direction of the parent perovskite cubic cell. The simplest models of the polarization of an untextured ceramic material with a random initial orientation of crystallites are considered. The results obtained are compared with experimental data.

Magnetic field angle dependent hysteresis of a magnetorheological suspension

NASA Astrophysics Data System (ADS)

Dohmen, Eike; Borin, Dmitry; Zubarev, Andrey

2017-12-01

Magnetorheological (MR) materials are of growing interest for a development and realisation of adaptive components and damping devices. The influence of the magnetic field orientation on the rheological properties of smart materials like MR fluids or magnetic hybrid composites is a key aspect which still is not fully understood, but occurs in almost every real life MR application. To cope with the practical needs and efficiently utilise these smart materials while taking into account their material phenomena experimentally validated practice-oriented models are needed. The authors use a coupled phenomenological approach to adjust and discuss a developed theoretical model based on experimentally obtained data. In addition the data helps to get a better understanding of internal processes and interrelations in MR suspensions.

Monetary rewards influence retrieval orientations.

PubMed

Halsband, Teresa M; Ferdinand, Nicola K; Bridger, Emma K; Mecklinger, Axel

2012-09-01

Reward anticipation during learning is known to support memory formation, but its role in retrieval processes is so far unclear. Retrieval orientations, as a reflection of controlled retrieval processing, are one aspect of retrieval that might be modulated by reward. These processes can be measured using the event-related potentials (ERPs) elicited by retrieval cues from tasks with different retrieval requirements, such as via changes in the class of targeted memory information. To determine whether retrieval orientations of this kind are modulated by reward during learning, we investigated the effects of high and low reward expectancy on the ERP correlates of retrieval orientation in two separate experiments. The reward manipulation at study in Experiment 1 was associated with later memory performance, whereas in Experiment 2, reward was directly linked to accuracy in the study task. In both studies, the participants encoded mixed lists of pictures and words preceded by high- or low-reward cues. After 24 h, they performed a recognition memory exclusion task, with words as the test items. In addition to a previously reported material-specific effect of retrieval orientation, a frontally distributed, reward-associated retrieval orientation effect was found in both experiments. These findings suggest that reward motivation during learning leads to the adoption of a reward-associated retrieval orientation to support the retrieval of highly motivational information. Thus, ERP retrieval orientation effects not only reflect retrieval processes related to the sought-for materials, but also relate to the reward conditions with which items were combined during encoding.

16 CFR 316.4 - Requirement to place warning labels on commercial electronic mail that contains sexually oriented...

Code of Federal Regulations, 2010 CFR

2010-01-01

... FEDERAL TRADE COMMISSION REGULATIONS UNDER SPECIFIC ACTS OF CONGRESS CAN-SPAM RULE § 316.4 Requirement to... avoid viewing the sexually oriented material, a recipient should delete the email message without...

Optical Signal Processing.

DTIC Science & Technology

1986-10-31

constructed from TeO2 sisting of lenses L6 and L- and a cylindrical lens C- material which is oriented to operate in the slow shear shape the Bragg...to focus the light into a horizontal line for efficient illumination. The Bragg cells are constructed from TeO2 material which is oriented to operate...source is a 10 mW He-Ne laser for which = 632.8 nm. The holographic element was constructed on a SO-120 glass plate with a reference-to-signal beam

Nano-Bio Quantum Technology for Device-Specific Materials

NASA Technical Reports Server (NTRS)

Choi, Sang H.

2009-01-01

The areas discussed are still under development: I. Nano structured materials for TE applications a) SiGe and Be.Te; b) Nano particles and nanoshells. II. Quantum technology for optical devices: a) Quantum apertures; b) Smart optical materials; c) Micro spectrometer. III. Bio-template oriented materials: a) Bionanobattery; b) Bio-fuel cells; c) Energetic materials.

Freshman Student Perceptions of Academic Programs and Academic Advising. Report No. One. Freshman Appraisal of Pre-Registration Information and Summer Orientation. Freshman Study. Report No. Two.

ERIC Educational Resources Information Center

Zink, Mary S.

An effort was made to determine freshmen student perceptions of academic advisory programs, pre-registration material, and summer orientation. To ascertain these perceptions a questionnaire was sent to all freshmen on the Orono Campus of the University of Maine. Approximately half of the students found the summer orientation program to be helpful,…

Augmented Performance Environment for Enhancing Interagency Coordination in Stability, Security, Transition, and Reconstruction (SSTR) Operations

DTIC Science & Technology

2009-02-01

assessments and meeting rehearsal and individual learning materials • Specify the metrics to be used to capture the quality of interagency...government; • Improve security; and • Promote reconstruction (Barno, 2004; Dziedzic & Siedl, 2005; Center for Army Lessons Learned (CALL), 2007). The...their orientations and creating group-level, hierarchical orientations out of the aggregated individual orientations (Wan, Chiu, Peng, & Tam , 2007

Characterization and modeling of a highly-oriented thin film for composite forming

NASA Astrophysics Data System (ADS)

White, K. D.; Sherwood, J. A.

2018-05-01

Ultra High Molecular Weight Polyethylene (UHMWPE) materials exhibit high impact strength, excellent abrasion resistance and high chemical resistance, making them attractive for a number of impact applications for automotive, marine and medical industries. One format of this class of materials that is being considered for the thermoforming process is a highly-oriented extruded thin film. Parts are made using a two-step manufacturing process that involves first producing a set of preforms and then consolidating these preforms into a final shaped part. To assist in the design of the processing parameters, simulations of the preforming and compression molding steps can be completed using the finite element method. Such simulations require material input data as developed through a comprehensive characterization test program, e.g. shear, tensile and bending, over the range of potential processing temperatures. The current research investigates the challenges associated with the characterization of thin, highly-oriented UHMWPE films. Variations in grip type, sample size and testing rates are explored to achieve convergence of the characterization data. Material characterization results are then used in finite element simulations of the tension test to explore element formulations that work well with the mechanical behavior. Comparisons of the results from the material characterization tests to results of simulations of the same test are performed to validate the finite element method parameters and the credibility of the user-defined material model.

Optimized growth and reorientation of anisotropic material based on evolution equations

NASA Astrophysics Data System (ADS)

Jantos, Dustin R.; Junker, Philipp; Hackl, Klaus

2018-07-01

Modern high-performance materials have inherent anisotropic elastic properties. The local material orientation can thus be considered to be an additional design variable for the topology optimization of structures containing such materials. In our previous work, we introduced a variational growth approach to topology optimization for isotropic, linear-elastic materials. We solved the optimization problem purely by application of Hamilton's principle. In this way, we were able to determine an evolution equation for the spatial distribution of density mass, which can be evaluated in an iterative process within a solitary finite element environment. We now add the local material orientation described by a set of three Euler angles as additional design variables into the three-dimensional model. This leads to three additional evolution equations that can be separately evaluated for each (material) point. Thus, no additional field unknown within the finite element approach is needed, and the evolution of the spatial distribution of density mass and the evolution of the Euler angles can be evaluated simultaneously.

Solution processed nanogap organic diodes based on liquid crystalline materials

NASA Astrophysics Data System (ADS)

Wang, Yi-Fei; Iino, Hiroaki; Hanna, Jun-ichi

2017-09-01

Co-planar nanogap organic diodes were fabricated with smectic liquid crystalline materials of the benzothienobenzothiophene (BTBT) derivative by a spin-coating technique. A high rectification ratio of the order of 106 at ±3 V was achieved when a liquid crystalline material of 2,7-didecyl benzothieno[3,2-b][1]benzothiophene (10-BTBT-10) was used in a device configuration of Al/10-BTBT-10/pentafluorobenzenethiol-treated Au on a glass substrate, which was 4 orders higher than that of the device based on non-liquid crystalline materials of 2,7-dibutyl benzothieno[3,2-b][1]benzothiophene (4-BTBT-4) and BTBT. Similar results were also observed when another liquid crystalline material of ω, ω'-dioctylterthiophene (8-TTP-8) and a non-liquid crystalline material of terthiophene (TTP) were used. These improved rectifications can be ascribed to the self-assembly properties and controllable molecular orientation of liquid crystalline materials, which made uniform perpendicular oriented polycrystalline films favorable for superior charge transport in nano-channels.

Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes

PubMed Central

Fei, Linfeng; Lei, Shuijin; Zhang, Wei-Bing; Lu, Wei; Lin, Ziyuan; Lam, Chi Hang; Chai, Yang; Wang, Yu

2016-01-01

A microscopic understanding of the growth mechanism of two-dimensional materials is of particular importance for controllable synthesis of functional nanostructures. Because of the lack of direct and insightful observations, how to control the orientation and the size of two-dimensional material grains is still under debate. Here we discern distinct formation stages for MoS2 flakes from the thermolysis of ammonium thiomolybdates using in situ transmission electron microscopy. In the initial stage (400 °C), vertically aligned MoS2 structures grow in a layer-by-layer mode. With the increasing temperature of up to 780 °C, the orientation of MoS2 structures becomes horizontal. When the growth temperature reaches 850 °C, the crystalline size of MoS2 increases by merging adjacent flakes. Our study shows direct observations of MoS2 growth as the temperature evolves, and sheds light on the controllable orientation and grain size of two-dimensional materials. PMID:27412892

Instructional Materials for Improved Job Performance.

ERIC Educational Resources Information Center

Foley, John P., Jr.

1978-01-01

Instructional materials developed in military research to improve performance of electromechanical maintenance tasks are described, with implications for teacher education. The materials require task analysis, job task relevance, and task-oriented training. Although many industries have implemented these techniques, teacher training institutions…

Anisotropic evaluation of synthetic surgical meshes.

PubMed

Saberski, E R; Orenstein, S B; Novitsky, Y W

2011-02-01

The material properties of meshes used in hernia repair contribute to the overall mechanical behavior of the repair. The anisotropic potential of synthetic meshes, representing a difference in material properties (e.g., elasticity) in different material axes, is not well defined to date. Haphazard orientation of anisotropic mesh material can contribute to inconsistent surgical outcomes. We aimed to characterize and compare anisotropic properties of commonly used synthetic meshes. Six different polypropylene (Trelex(®), ProLite™, Ultrapro™), polyester (Parietex™), and PTFE-based (Dualmesh(®), Infinit) synthetic meshes were selected. Longitudinal and transverse axes were defined for each mesh, and samples were cut in each axis orientation. Samples underwent uniaxial tensile testing, from which the elastic modulus (E) in each axis was determined. The degree of anisotropy (λ) was calculated as a logarithmic expression of the ratio between the elastic modulus in each axis. Five of six meshes displayed significant anisotropic behavior. Ultrapro™ and Infinit exhibited approximately 12- and 20-fold differences between perpendicular axes, respectively. Trelex(®), ProLite™, and Parietex™ were 2.3-2.4 times. Dualmesh(®) was the least anisotropic mesh, without marked difference between the axes. Anisotropy of synthetic meshes has been underappreciated. In this study, we found striking differences between elastic properties of perpendicular axes for most commonly used synthetic meshes. Indiscriminate orientation of anisotropic mesh may adversely affect hernia repairs. Proper labeling of all implants by manufacturers should be mandatory. Understanding the specific anisotropic behavior of synthetic meshes should allow surgeons to employ rational implant orientation to maximize outcomes of hernia repair.

Characterization of nuclear graphite elastic properties using laser ultrasonic methods

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

Zeng, Fan W; Han, Karen; Olasov, Lauren R

2015-01-01

Laser ultrasonic methods have been used to characterize the elastic behaviors of commercially-available and legacy nuclear graphites. Since ultrasonic techniques are sensitive to various aspects of graphite microstructure including preferred grain orientation, microcrack orientation and porosity, laser ultrasonics is a candidate technique for monitoring graphite degradation and structural integrity in environments expected in high-temperature, gas-cooled nuclear reactors. Aspects of materials texture can be assessed by studying ultrasonic wavespeeds as a function of propagation direction and polarization. Shear wave birefringence measurements, in particular, can be used to evaluate elastic anisotropy. In this work, laser ultrasonic measurements of graphite moduli have beenmore » made to provide insight into the relationship between the microstructures and the macroscopic stiffnesses of these materials. In particular, laser ultrasonic measurements have been made using laser line sources to produce shear waves with specific polarizations. By varying the line orientation relative to the sample, shear wave birefringence measurements have been recorded. Results from shear wave birefringence measurements show that an isostatically molded graphite, such as PCIB, behaves isotropically, while an extruded graphite, such as H-451, displays significant ultrasonic texture. Graphites have complicated microstructures that depend on the manufacturing processes used, and ultrasonic texture in these materials could originate from grain orientation and preferred microcrack alignment. Effects on material isotropy due to service related microstructural changes are possible and the ultimate aim of this work is to determine the degree to which these changes can be assessed nondestructively using laser ultrasonics measurements« less

Oxides for sustainable photovoltaics with earth-abundant materials

NASA Astrophysics Data System (ADS)

Wagner, Alexander; Stahl, Mathieu; Ehrhardt, Nikolai; Fahl, Andreas; Ledig, Johannes; Waag, Andreas; Bakin, Andrey

2014-03-01

Energy conversion technologies are aiming to extremely high power capacities per year. Nontoxicity and abundance of the materials are the key requirements to a sustainable photovoltaic technology. Oxides are among the key materials to reach these goals. We investigate the influence of thin buffer layers on the performance of an ZnO:Al/buffer/Cu2O solar cells. Introduction of a thin ZnO or Al2O3 buffer layer, grown by thermal ALD, between ZnO:Al and Cu2O resulted in 45% increase of the solar cell efficiency. VPE growth of Cu2O employing elemental copper and pure oxygen as precursor materials is presented. The growth is performed on MgO substrates with the (001) orientation. On- and off- oriented substrates have been employed and the growth results are compared. XRD investigations show the growth of the (110) oriented Cu2O for all temperatures, whereas at a high substrate temperature additional (001) Cu2O growth occurs. An increase of the oxygen partial pressure leads to a more pronounced 2D growth mode, whereby pores between the islands still remain. The implementation of off-axis substrates with 3.5° and 5° does not lead to an improvement of the layer quality. The (110) orientation remains predominant, the grain size decreases and the FWHM of the (220) peak increases. From the AFM images it is concluded, that the (110) surface grows with a tilt angle to the substrate surface.

Method and apparatus for millimeter-wave detection of thermal waves for materials evaluation

DOEpatents

Gopalsami, Nachappa; Raptis, Apostolos C.

1991-01-01

A method and apparatus for generating thermal waves in a sample and for measuring thermal inhomogeneities at subsurface levels using millimeter-wave radiometry. An intensity modulated heating source is oriented toward a narrow spot on the surface of a material sample and thermal radiation in a narrow volume of material around the spot is monitored using a millimeter-wave radiometer; the radiometer scans the sample point-by-point and a computer stores and displays in-phase and quadrature phase components of thermal radiations for each point on the scan. Alternatively, an intensity modulated heating source is oriented toward a relatively large surface area in a material sample and variations in thermal radiation within the full field of an antenna array are obtained using an aperture synthesis radiometer technique.

Inheritance of Crystallographic Orientation during Lithiation/Delithiation Processes of Single-Crystal α-Fe2O3 Nanocubes in Lithium-Ion Batteries.

PubMed

Ma, Xiaowei; Zhang, Manyu; Liang, Chongyun; Li, Yuesheng; Wu, Jingjing; Che, Renchao

2015-11-04

Iron oxides are very promising anode materials based on conversion reactions for lithium-ion batteries (LIBs). During conversion processes, the crystal structure and composition of the electrode material are drastically changed. Surprisingly, in our study, inheritance of a crystallographic orientation was found during lithiation/delithiation processes of single-crystal α-Fe2O3 nanocubes by ex situ transmission electron microscopy. Single-crystal α-Fe2O3 was first transformed into numerous Fe nanograins embedded in a Li2O matrix, and then the conversion between Fe and FeO nanograins became the main reversible electrochemical reaction for energy storage. Interestingly, these Fe/FeO nanograins had almost the same crystallographic orientation, indicating that the lithiated/delithiated products can inherit the crystallographic orientation of single-crystal α-Fe2O3. This finding is important for understanding the detailed electrochemical conversion processes of iron oxides, and this feature may also exist during lithiation/delithiation processes of other transition-metal oxides.

Dependence of Crystallographic Orientation on Pitting Corrosion Behavior of Ni-Fe-Cr Alloy 028

NASA Astrophysics Data System (ADS)

Zhang, LiNa; Szpunar, Jerzy A.; Dong, JianXin; Ojo, Olanrewaju A.; Wang, Xu

2018-06-01

The influence of crystallographic orientation on the pitting corrosion behavior of Ni-Fe-Cr alloy 028 was studied using a combination of X-ray diffraction (XRD), electron backscatter diffraction (EBSD), potentiodynamic polarization technique, and atomic force microscopy (AFM). The results show that there is anisotropy of pitting corrosion that strongly depends on crystallographic orientation of the surface plane. The distribution of pit density in a standard stereographic triangle indicates that the crystallographic planes close to {100} are more prone to pitting corrosion compared to planes {110} and {111}. The surface energy calculation of (001) and (111) shows that the plane with a high atomic packing density has a low surface energy with concomitant strong resistance to pitting corrosion. A correlation function between crystallographic orientation and pitting corrosion susceptibility suggests a method that not only predicts the pitting resistance of known textured materials, but also could help to improve corrosion resistance by controlling material texture.

Embodying pervasive discrimination: a decomposition of sexual orientation inequalities in health in a population-based cross-sectional study in Northern Sweden.

PubMed

Gustafsson, Per E; Linander, Ida; Mosquera, Paola A

2017-01-21

Studies from Sweden and abroad have established health inequalities between heterosexual and non-heterosexual people. Few studies have examined the underpinnings of such sexual orientation inequalities in health. To expand this literature, the present study aimed to employ decomposition analysis to explain health inequalities between people with heterosexual and non-heterosexual orientation in Sweden, a country with an international reputation for heeding the human rights of non-heterosexual people. Participants (N = 23,446) came from a population-based cross-sectional survey in the four northernmost counties in Sweden in 2014. Participants completed self-administered questionnaires, covering sexual orientation, mental and general physical health, social conditions and unmet health care needs, and sociodemographic data was retrieved from total population registers. Sexual orientation inequalities in health were decomposed by Blinder-Oaxaca decomposition analysis. Results showed noticeable mental and general health inequalities between heterosexual and non-heterosexual orientation groups. Health inequalities were partly explained (total explained fraction 64-74%) by inequalities in degrading treatment (24-26% of the explained fraction), but to a considerable degree also by material conditions (38-45%) and unmet care needs (25-43%). Psychosocial experiences may be insufficient to explain and understand health inequalities by sexual orientation in a reputedly 'gay-friendly' setting. Less overt forms of structural discrimination may need to be considered to capture the pervasive material discrimination that seems to underpin the embodiment of sexual minority inequalities. This ought to be taken into consideration in research, policy-making and monitoring aiming to work towards equity in health across sexual orientations.

Crystal Orientation Controlled Photovoltaic Properties of Multilayer GaAs Nanowire Arrays.

PubMed

Han, Ning; Yang, Zai-Xing; Wang, Fengyun; Yip, SenPo; Li, Dapan; Hung, Tak Fu; Chen, Yunfa; Ho, Johnny C

2016-06-28

In recent years, despite significant progress in the synthesis, characterization, and integration of various nanowire (NW) material systems, crystal orientation controlled NW growth as well as real-time assessment of their growth-structure-property relationships still presents one of the major challenges in deploying NWs for practical large-scale applications. In this study, we propose, design, and develop a multilayer NW printing scheme for the determination of crystal orientation controlled photovoltaic properties of parallel GaAs NW arrays. By tuning the catalyst thickness and nucleation and growth temperatures in the two-step chemical vapor deposition, crystalline GaAs NWs with uniform, pure ⟨110⟩ and ⟨111⟩ orientations and other mixture ratios can be successfully prepared. Employing lift-off resists, three-layer NW parallel arrays can be easily attained for X-ray diffraction in order to evaluate their growth orientation along with the fabrication of NW parallel array based Schottky photovoltaic devices for the subsequent performance assessment. Notably, the open-circuit voltage of purely ⟨111⟩-oriented NW arrayed cells is far higher than that of ⟨110⟩-oriented NW arrayed counterparts, which can be interpreted by the different surface Fermi level pinning that exists on various NW crystal surface planes due to the different As dangling bond densities. All this indicates the profound effect of NW crystal orientation on physical and chemical properties of GaAs NWs, suggesting the careful NW design considerations for achieving optimal photovoltaic performances. The approach presented here could also serve as a versatile and powerful platform for in situ characterization of other NW materials.

Multimaterial magnetically assisted 3D printing of composite materials.

PubMed

Kokkinis, Dimitri; Schaffner, Manuel; Studart, André R

2015-10-23

3D printing has become commonplace for the manufacturing of objects with unusual geometries. Recent developments that enabled printing of multiple materials indicate that the technology can potentially offer a much wider design space beyond unusual shaping. Here we show that a new dimension in this design space can be exploited through the control of the orientation of anisotropic particles used as building blocks during a direct ink-writing process. Particle orientation control is demonstrated by applying low magnetic fields on deposited inks pre-loaded with magnetized stiff platelets. Multimaterial dispensers and a two-component mixing unit provide additional control over the local composition of the printed material. The five-dimensional design space covered by the proposed multimaterial magnetically assisted 3D printing platform (MM-3D printing) opens the way towards the manufacturing of functional heterogeneous materials with exquisite microstructural features thus far only accessible by biological materials grown in nature.

Development of Problem-Based Learning Oriented Teaching Learning Materials to Facilitate Students’ Mastery of Concept and Critical Thinking Skill

NASA Astrophysics Data System (ADS)

Reza, M.; Ibrahim, M.; Rahayu, Y. S.

2018-01-01

This research aims to develop problem-based learning oriented teaching materials to improve students’ mastery of concept and critical thinking skill. Its procedure was divided into two phases; developmental phase and experimental phase. This developmental research used Four-D Model. However, within this research, the process of development would not involve the last stages, which is disseminate. The teaching learning materials which were developed consist of lesson plan, student handbook, student worksheet, achievement test and critical thinking skill test. The experimental phase employs a research design called one group pretest-posttest design. Results show that the validity of the teaching materials which were developed was good and revealed the enhancement of students’ activities with positive response to the teaching learning process. Furthermore, the learning materials improve the students’ mastery of concept and critical thinking skill.

Buffer layers on metal alloy substrates for superconducting tapes

DOEpatents

Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

2004-10-05

An article including a substrate, at least one intermediate layer upon the surface of the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the at least one intermediate layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected I.sub.c 's of over 200 Amperes across a sample 1 cm wide.

Hetero-junction photovoltaic device and method of fabricating the device

DOEpatents

Aytug, Tolga; Christen, David K; Paranthaman, Mariappan Parans; Polat, Ozgur

2014-02-10

A hetero-junction device and fabrication method in which phase-separated n-type and p-type semiconductor pillars define vertically-oriented p-n junctions extending above a substrate. Semiconductor materials are selected for the p-type and n-type pillars that are thermodynamically stable and substantially insoluble in one another. An epitaxial deposition process is employed to form the pillars on a nucleation layer and the mutual insolubility drives phase separation of the materials. During the epitaxial deposition process, the orientation is such that the nucleation layer initiates propagation of vertical columns resulting in a substantially ordered, three-dimensional structure throughout the deposited material. An oxidation state of at least a portion of one of the p-type or the n-type semiconductor materials is altered relative to the other, such that the band-gap energy of the semiconductor materials differ with respect to stoichiometric compositions and the device preferentially absorbs particular selected bands of radiation.

System and method for manipulating domain pinning and reversal in ferromagnetic materials

DOEpatents

Silevitch, Daniel M.; Rosenbaum, Thomas F.; Aeppli, Gabriel

2013-10-15

A method for manipulating domain pinning and reversal in a ferromagnetic material comprises applying an external magnetic field to a uniaxial ferromagnetic material comprising a plurality of magnetic domains, where each domain has an easy axis oriented along a predetermined direction. The external magnetic field is applied transverse to the predetermined direction and at a predetermined temperature. The strength of the magnetic field is varied at the predetermined temperature, thereby isothermally regulating pinning of the domains. A magnetic storage device for controlling domain dynamics includes a magnetic hard disk comprising a uniaxial ferromagnetic material, a magnetic recording head including a first magnet, and a second magnet. The ferromagnetic material includes a plurality of magnetic domains each having an easy axis oriented along a predetermined direction. The second magnet is positioned adjacent to the magnetic hard disk and is configured to apply a magnetic field transverse to the predetermined direction.

Multimaterial magnetically assisted 3D printing of composite materials

NASA Astrophysics Data System (ADS)

Kokkinis, Dimitri; Schaffner, Manuel; Studart, André R.

2015-10-01

3D printing has become commonplace for the manufacturing of objects with unusual geometries. Recent developments that enabled printing of multiple materials indicate that the technology can potentially offer a much wider design space beyond unusual shaping. Here we show that a new dimension in this design space can be exploited through the control of the orientation of anisotropic particles used as building blocks during a direct ink-writing process. Particle orientation control is demonstrated by applying low magnetic fields on deposited inks pre-loaded with magnetized stiff platelets. Multimaterial dispensers and a two-component mixing unit provide additional control over the local composition of the printed material. The five-dimensional design space covered by the proposed multimaterial magnetically assisted 3D printing platform (MM-3D printing) opens the way towards the manufacturing of functional heterogeneous materials with exquisite microstructural features thus far only accessible by biological materials grown in nature.

Examining the Self-Assembly of Rod-Coil Block Copolymers via Physics Based Polymer Models and Polarized X-Ray Scattering

NASA Astrophysics Data System (ADS)

Hannon, Adam; Sunday, Daniel; Windover, Donald; Liman, Christopher; Bowen, Alec; Khaira, Gurdaman; de Pablo, Juan; Delongchamp, Dean; Kline, R. Joseph

Photovoltaics, flexible electronics, and stimuli-responsive materials all require enhanced methodology to examine their nanoscale molecular orientation. The mechanical, electronic, optical, and transport properties of devices made from these materials are all a function of this orientation. The polymer chains in these materials are best modeled as semi-flexible to rigid rods. Characterizing the rigidity and molecular orientation of these polymers non-invasively is currently being pursued by using polarized resonant soft X-ray scattering (P-RSoXS). In this presentation, we show recent work on implementing such a characterization process using a rod-coil block copolymer system in the rigid-rod limit. We first demonstrate how we have used physics based models such as self-consistent field theory (SCFT) in non-polarized RSoXS work to fit scattering profiles for thin film coil-coil PS- b-PMMA block copolymer systems. We then show by using a wormlike chain partition function in the SCFT formulism to model the rigid-rod block, the methodology can be used there as well to extract the molecular orientation of the rod block from a simulated P-RSoXS experiment. The results from the work show the potential of the technique to extract thermodynamic and morphological sample information.

Swim stress, motion, and deformation of active matter: effect of an external field.

PubMed

Takatori, Sho C; Brady, John F

2014-12-21

We analyze the stress, dispersion, and average swimming speed of self-propelled particles subjected to an external field that affects their orientation and speed. The swimming trajectory is governed by a competition between the orienting influence (i.e., taxis) associated with the external (e.g., magnetic, gravitational, thermal, nutrient concentration) field versus the effects that randomize the particle orientations (e.g., rotary Brownian motion and/or an intrinsic tumbling mechanism like the flagella of bacteria). The swimmers' motion is characterized by a mean drift velocity and an effective translational diffusivity that becomes anisotropic in the presence of the orienting field. Since the diffusivity yields information about the micromechanical stress, the anisotropy generated by the external field creates a normal stress difference in the recently developed "swim stress" tensor [Takatori, Yan, and Brady, Phys. Rev. Lett., 2014]. This property can be exploited in the design of soft, compressible materials in which their size, shape, and motion can be manipulated and tuned by loading the material with active swimmers. Since the swimmers exert different normal stresses in different directions, the material can compress/expand, elongate, and translate depending on the external field strength. Such an active system can be used as nano/micromechanical devices and motors. Analytical solutions are corroborated by Brownian dynamics simulations.

Sample-based synthesis of two-scale structures with anisotropy

DOE PAGES

Liu, Xingchen; Shapiro, Vadim

2017-05-19

A vast majority of natural or synthetic materials are characterized by their anisotropic properties, such as stiffness. Such anisotropy is effected by the spatial distribution of the fine-scale structure and/or anisotropy of the constituent phases at a finer scale. In design, proper control of the anisotropy may greatly enhance the efficiency and performance of synthesized structures. In this paper, we propose a sample-based two-scale structure synthesis approach that explicitly controls anisotropic effective material properties of the structure on the coarse scale by orienting sampled material neighborhoods at the fine scale. We first characterize the non-uniform orientations distribution of the samplemore » structure by showing that the principal axes of an orthotropic material may be determined by the eigenvalue decomposition of its effective stiffness tensor. Such effective stiffness tensors can be efficiently estimated based on the two-point correlation functions of the fine-scale structures. Then we synthesize the two-scale structure by rotating fine-scale structures from the sample to follow a given target orientation field. Finally, the effectiveness of the proposed approach is demonstrated through examples in both 2D and 3D.« less

Sample-based synthesis of two-scale structures with anisotropy

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

Liu, Xingchen; Shapiro, Vadim

A vast majority of natural or synthetic materials are characterized by their anisotropic properties, such as stiffness. Such anisotropy is effected by the spatial distribution of the fine-scale structure and/or anisotropy of the constituent phases at a finer scale. In design, proper control of the anisotropy may greatly enhance the efficiency and performance of synthesized structures. In this paper, we propose a sample-based two-scale structure synthesis approach that explicitly controls anisotropic effective material properties of the structure on the coarse scale by orienting sampled material neighborhoods at the fine scale. We first characterize the non-uniform orientations distribution of the samplemore » structure by showing that the principal axes of an orthotropic material may be determined by the eigenvalue decomposition of its effective stiffness tensor. Such effective stiffness tensors can be efficiently estimated based on the two-point correlation functions of the fine-scale structures. Then we synthesize the two-scale structure by rotating fine-scale structures from the sample to follow a given target orientation field. Finally, the effectiveness of the proposed approach is demonstrated through examples in both 2D and 3D.« less

New piezoelectric materials for SAW filters

NASA Astrophysics Data System (ADS)

Anghelescu, Adrian; Nedelcu, Monica

2010-11-01

Scientific research of surface acoustic wave (SAW) devices had an early start by the end of 1960s and led to the development of high frequency and small size piezo devices. A sustained effort was dedicated for these components to be transformed into many more interesting applications for telecom market. Recently the employment of new piezo materials and crystallographic orientations open new opportunities for SAW filters. New piezoelectric crystals of gallium orthophosphate (GaPO4) provide higher electromechanical coupling than quartz, while maintaining temperature compensated characteristics similar to quartz. Based on this material phase transition of 970°C, development of new piezo devices to operate at higher temperatures up to 800°C can be done. SAW velocities about 30% lower than ST-X quartz, favors smaller and more compact devices. Other advantages of GaPO4 are: stability with high resistance to stress induced twinning, 3~4 times higher electromechanical coupling than quartz and existence of SAW temperature compensated orientations. Another family of new materials of the trigonal 32 class has received much attention recently because of their temperature behavior similar to quartz and the promise of higher electromechanical coupling coefficients. It is the family of langasite (LGS, La3Ga5SiO14), langatate (LGT, La3Ga5.5Ta0.5O14) and langanite (La3Ga5.5Nb0.5O14). Langasite crystals, easier to obtain and with the value of electromechanical coupling coefficient intermediate between quartz and lithium tantalate (k2=0.32% for 0°, 140°, 22.5° orientation and k2=0.38% for 0°, 140°, 25° orientation), enable us to design SAW filters with a relative pass band of 0.3% to 0.85%. Other piezoelectric materials are reviewed for comparison.

Micromechanical investigation of ductile failure in Al 5083-H116 via 3D unit cell modeling

NASA Astrophysics Data System (ADS)

Bomarito, G. F.; Warner, D. H.

2015-01-01

Ductile failure is governed by the evolution of micro-voids within a material. The micro-voids, which commonly initiate at second phase particles within metal alloys, grow and interact with each other until failure occurs. The evolution of the micro-voids, and therefore ductile failure, depends on many parameters (e.g., stress state, temperature, strain rate, void and particle volume fraction, etc.). In this study, the stress state dependence of the ductile failure of Al 5083-H116 is investigated by means of 3-D Finite Element (FE) periodic cell models. The cell models require only two pieces of information as inputs: (1) the initial particle volume fraction of the alloy and (2) the constitutive behavior of the matrix material. Based on this information, cell models are subjected to a given stress state, defined by the stress triaxiality and the Lode parameter. For each stress state, the cells are loaded in many loading orientations until failure. Material failure is assumed to occur in the weakest orientation, and so the orientation in which failure occurs first is considered as the critical orientation. The result is a description of material failure that is derived from basic principles and requires no fitting parameters. Subsequently, the results of the simulations are used to construct a homogenized material model, which is used in a component-scale FE model. The component-scale FE model is compared to experiments and is shown to over predict ductility. By excluding smaller nucleation events and load path non-proportionality, it is concluded that accuracy could be gained by including more information about the true microstructure in the model; emphasizing that its incorporation into micromechanical models is critical to developing quantitatively accurate physics-based ductile failure models.

Magnetorheological finishing with chemically modified fluids for studying material removal of single-crystal ZnS

NASA Astrophysics Data System (ADS)

Salzman, S.; Romanofsky, H. J.; Clara, Y. I.; Giannechini, L. J.; West, Garrett J.; Lambropoulos, J. C.; Jacobs, S. D.

2013-09-01

Magnetorheological finishing (MRF) of polycrystalline, chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and zinc selenide (ZnSe) can leave millimeter-size artifacts on the part surface. These pebble-like features come from the anisotropic mechanical and chemical properties of the ceramic material and from the CVD growth process itself. The resulting surface texture limits the use of MRF for polishing aspheric and other complex shapes using these important infrared (IR) ceramics. An investigation of the individual contributions of chemistry and mechanics to polishing of other polycrystalline ceramics has been employed in the past to overcome similar material anisotropy problems. The approach taken was to study the removal process for the different single-crystal orientations that comprise the ceramic, making adjustments to mechanics (polishing abrasive type and concentration) and polishing slurry chemistry (primarily pH) to equalize the removal rate for all crystal orientations. Polishing with the modified slurry was shown to prevent the development of surface texture. Here we present mechanical (microhardness testing) and chemical (acid etching) studies performed on the four single-crystal orientations of ZnS: 100, 110, 111, and 311. We found that the (111) plane is 35% to 55% harder and 30% to 40% more resistant to chemical etching than the other three planes. This relatively high degree of variation in these properties can help to explain the surface texture developed from MRF of the polycrystalline material. Theoretical calculations of microhardness, planar, and bond densities are presented and compared with the experimental data. Here surface characterization of these single-crystal orientations of ZnS for material removal and roughness with chemically modified MR fluids at various pH levels between pH 4 and pH 6 are presented for the first time.

Effect of Ply Orientation and Crack Location on SIFs in Finite Multilayers with Aligned Cracks

NASA Astrophysics Data System (ADS)

Chen, Linfeng; Pindera, Marek-Jerzy

2008-02-01

An exact elasticity solution is presented for arbitrarily laminated finite multilayers in a state of generalized plane deformation under horizontally pinned end constraints that are weakened by aligned cracks. Based on half-range Fourier series and the local/global stiffness matrix approach, the mixed boundary-value problem is reduced to Cauchy-type singular integral equations in the unknown displacement discontinuities. Solution to these equations is obtained using the approach developed by Erdogan and co-workers. Numerical results quantify the thus-far undocumented geometric and material effects on Mode I, II and III stress intensity factors in composite multilayers with interacting cracks under uniform vertical displacement. These effects include finite dimensions, crack location, material anisotropy due to a unidirectional fiber-reinforced layer/s orientation, and orientational grading.

Infrared vibrational nanocrystallography and nanoimaging

PubMed Central

Muller, Eric A.; Pollard, Benjamin; Bechtel, Hans A.; van Blerkom, Peter; Raschke, Markus B.

2016-01-01

Molecular solids and polymers can form low-symmetry crystal structures that exhibit anisotropic electron and ion mobility in engineered devices or biological systems. The distribution of molecular orientation and disorder then controls the macroscopic material response, yet it is difficult to image with conventional techniques on the nanoscale. We demonstrated a new form of optical nanocrystallography that combines scattering-type scanning near-field optical microscopy with both optical antenna and tip-selective infrared vibrational spectroscopy. From the symmetry-selective probing of molecular bond orientation with nanometer spatial resolution, we determined crystalline phases and orientation in aggregates and films of the organic electronic material perylenetetracarboxylic dianhydride. Mapping disorder within and between individual nanoscale domains, the correlative hybrid imaging of nanoscale heterogeneity provides insight into defect formation and propagation during growth in functional molecular solids. PMID:27730212

Influence of Molecular Shape on Molecular Orientation and Stability of Vapor-Deposited Organic Semiconductors

NASA Astrophysics Data System (ADS)

Walters, Diane M.; Johnson, Noah D.; Ediger, M. D.

Physical vapor deposition is commonly used to prepare active layers in organic electronics. Recently, it has been shown that molecular orientation and packing can be tuned by changing the substrate temperature during deposition, while still producing macroscopically homogeneous films. These amorphous materials can be highly anisotropic when prepared with low substrate temperatures, and they can exhibit exceptional kinetic stability; films retain their favorable packing when heated to high temperatures. Here, we study the influence of molecular shape on molecular orientation and stability. We investigate disc-shaped molecules, such as TCTA and m-MTDATA, nearly spherical molecules, such as Alq3, and linear molecules covering a broad range of aspect ratios, such as p-TTP and BSB-Cz. Disc-shaped molecules have preferential horizontal orientation when deposited at low substrate temperatures, and their orientation can be tuned by changing the substrate temperature. Alq3 forms stable, amorphous films that are optically isotropic when vapor deposited over a broad range of substrate temperatures. This work may guide the choice of material and deposition conditions for vapor-deposited films used in organic electronics and allow for more efficient devices to be fabricated.

Rapid, all-optical crystal orientation imaging of two-dimensional transition metal dichalcogenide monolayers

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

David, Sabrina N.; Zhai, Yao; van der Zande, Arend M.

Two-dimensional (2D) atomic materials such as graphene and transition metal dichalcogenides (TMDCs) have attracted significant research and industrial interest for their electronic, optical, mechanical, and thermal properties. While large-area crystal growth techniques such as chemical vapor deposition have been demonstrated, the presence of grain boundaries and orientation of grains arising in such growths substantially affect the physical properties of the materials. There is currently no scalable characterization method for determining these boundaries and orientations over a large sample area. We here present a second-harmonic generation based microscopy technique for rapidly mapping grain orientations and boundaries of 2D TMDCs. We experimentallymore » demonstrate the capability to map large samples to an angular resolution of ±1° with minimal sample preparation and without involved analysis. A direct comparison of the all-optical grain orientation maps against results obtained by diffraction-filtered dark-field transmission electron microscopy plus selected-area electron diffraction on identical TMDC samples is provided. This rapid and accurate tool should enable large-area characterization of TMDC samples for expedited studies of grain boundary effects and the efficient characterization of industrial-scale production techniques.« less

Identification and Modelling of the In-Plane Reinforcement Orientation Variations in a CFRP Laminate Produced by Manual Lay-Up

NASA Astrophysics Data System (ADS)

Davila, Yves; Crouzeix, Laurent; Douchin, Bernard; Collombet, Francis; Grunevald, Yves-Henri

2017-08-01

Reinforcement angle orientation has a significant effect on the mechanical properties of composite materials. This work presents a methodology to introduce variable reinforcement angles into finite element (FE) models of composite structures. The study of reinforcement orientation variations uses meta-models to identify and control a continuous variation across the composite ply. First, the reinforcement angle is measured through image analysis techniques of the composite plies during the lay-up phase. Image analysis results show that variations in the mean ply orientations are between -0.5 and 0.5° with standard deviations ranging between 0.34 and 0.41°. An automatic post-treatment of the images determines the global and local angle variations yielding good agreements visually and numerically between the analysed images and the identified parameters. A composite plate analysed at the end of the cooling phase is presented as a case of study. Here, the variation in residual strains induced by the variability in the reinforcement orientation are up to 28% of the strain field of the homogeneous FE model. The proposed methodology has shown its capabilities to introduce material and geometrical variability into FE analysis of layered composite structures.

Identification and Modelling of the In-Plane Reinforcement Orientation Variations in a CFRP Laminate Produced by Manual Lay-Up

NASA Astrophysics Data System (ADS)

Davila, Yves; Crouzeix, Laurent; Douchin, Bernard; Collombet, Francis; Grunevald, Yves-Henri

2018-06-01

Reinforcement angle orientation has a significant effect on the mechanical properties of composite materials. This work presents a methodology to introduce variable reinforcement angles into finite element (FE) models of composite structures. The study of reinforcement orientation variations uses meta-models to identify and control a continuous variation across the composite ply. First, the reinforcement angle is measured through image analysis techniques of the composite plies during the lay-up phase. Image analysis results show that variations in the mean ply orientations are between -0.5 and 0.5° with standard deviations ranging between 0.34 and 0.41°. An automatic post-treatment of the images determines the global and local angle variations yielding good agreements visually and numerically between the analysed images and the identified parameters. A composite plate analysed at the end of the cooling phase is presented as a case of study. Here, the variation in residual strains induced by the variability in the reinforcement orientation are up to 28% of the strain field of the homogeneous FE model. The proposed methodology has shown its capabilities to introduce material and geometrical variability into FE analysis of layered composite structures.

Thin film with oriented cracks on a flexible substrate

DOEpatents

Feng, Bao; McGilvray, Andrew; Shi, Bo

2010-07-27

A thermoelectric film is disclosed. The thermoelectric film includes a substrate that is substantially electrically non-conductive and flexible and a thermoelectric material that is deposited on at least one surface of the substrate. The thermoelectric film also includes multiple cracks oriented in a predetermined direction.

Graphoepitaxy by encapsulation

DOEpatents

Geis, Michael W.; Smith, Henry I.; Antoniadis, Dimitri A.; Flanders, Dale C.

1986-01-01

Improvements on the graphoepitaxial process for obtaining epitaxial or preferred orientation films are described wherein a cap of material is formed over the film to be oriented, artificial surface-relief structure may be present in the substrate, the cap, or both, and the film may be heated by irradiation with electromagnetic radiation.

14 CFR 1213.108 - Multimedia materials.

Code of Federal Regulations, 2013 CFR

2013-01-01

....108 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS... original or duplicate files of news-oriented imagery and other digital multimedia material generated within... the opinion of the installations, would be appropriate for use as news feed material or features in...

14 CFR 1213.108 - Multimedia materials.

Code of Federal Regulations, 2011 CFR

2011-01-01

....108 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS... original or duplicate files of news-oriented imagery and other digital multimedia material generated within... the opinion of the installations, would be appropriate for use as news feed material or features in...

14 CFR 1213.108 - Multimedia materials.

Code of Federal Regulations, 2012 CFR

2012-01-01

....108 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS... original or duplicate files of news-oriented imagery and other digital multimedia material generated within... the opinion of the installations, would be appropriate for use as news feed material or features in...

14 CFR 1213.108 - Multimedia materials.

Code of Federal Regulations, 2010 CFR

2010-01-01

....108 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION RELEASE OF INFORMATION TO NEWS... original or duplicate files of news-oriented imagery and other digital multimedia material generated within... the opinion of the installations, would be appropriate for use as news feed material or features in...

Thermoelectric properties of Zn4Sb3/CeFe(4-x)CoxSb12 nano-layered superlattices modified by MeV Si ion beam

NASA Astrophysics Data System (ADS)

Budak, S.; Guner, S.; Minamisawa, R. A.; Muntele, C. I.; Ila, D.

2014-08-01

We prepared multilayers of superlattice thin film system with 50 periodic alternating nano-layers of semiconducting half-Heusler β-Zn4Sb3 and skutterudite CeFe2Co2Sb12 compound thin films using ion beam assisted deposition (IBAD) with Au layers deposited on both sides as metal contacts. The deposited multilayer thin films have alternating layers about 5 nm thick. The total thickness of the multilayer system is 275 nm. The superlattices were then bombarded by 5 MeV Si ion at six different fluences to form nano-cluster structures. The film thicknesses and composition were monitored by Rutherford backscattering spectrometry (RBS) before and after MeV ion bombardment. We have measured the thermoelectric efficiency, Figure of Merit ZT, of the fabricated device by measuring the cross plane thermal conductivity by the 3rd harmonic (3ω) method, the cross plane Seebeck coefficient, and the electrical conductivity using the van der Pauw method before and after the MeV ion bombardments. We reached the remarkable thermoelectric Figure of Merit results at optimal fluences.

Multi-Aperture Shower Design for the Improvement of the Transverse Uniformity of MOCVD-Derived GdYBCO Films

PubMed Central

Zhao, Ruipeng; Liu, Qing; Xia, Yudong; Zhang, Fei; Lu, Yuming; Cai, Chuanbing; Tao, Bowan; Li, Yanrong

2017-01-01

A multi-aperture shower design is reported to improve the transverse uniformity of GdYBCO superconducting films on the template of sputtered-LaMnO3/epitaxial-MgO/IBAD-MgO/solution deposition planarization (SDP)-Y2O3-buffered Hastelloy tapes. The GdYBCO films were prepared by the metal organic chemical vapor deposition (MOCVD) process. The transverse uniformities of structure, morphology, thickness, and performance were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), step profiler, and the standard four-probe method using the criteria of 1 μV/cm, respectively. Through adopting the multi-aperture shower instead of the slit shower, measurement by step profiler revealed that the thickness difference between the middle and the edges based on the slit shower design was well eliminated. Characterization by SEM showed that a GdYBCO film with a smooth surface was successfully prepared. Moreover, the transport critical current density (Jc) of its middle and edge positions at 77 K and self-field were found to be over 5 MA/cm2 through adopting the micro-bridge four-probe method. PMID:28914793

High utilization ratio of metal organic sources for MOCVD-derived GdYBCO films based on a narrow channel reaction chamber

NASA Astrophysics Data System (ADS)

Zhao, Ruipeng; Liu, Qing; Xia, Yudong; Tang, Hao; Lu, Yuming; Cai, Chuanbing; Tao, Bowan; Li, Yanrong

2018-01-01

A narrow channel reaction chamber is designed in our home-made MOCVD system and applied to deposit GdYBCO films on the template of LaMnO3/epitaxial MgO/IBAD-MgO/solution deposition planarization-Y2O3-buffered Hastelloy tapes. In the reaction chamber, metal organic sources are transferred from the inlet to the outlet along the direction of the tape movement. Thus, compared to the vertical injection way of metal organic sources, the residence time of metal organic sources on the surface of substrates would be extended through adopting the novel reaction chamber. Therefore, the utilization of metal organic sources, which is calculated according to the measured results of experiments, can reach 31%. Additionally, the utilization ratio of metal organic sources based on the novel reaction chamber is basically two times as much as that of the commonly used vertical injection slit shower. What is more, through adjusting the process, the critical current density of 300 nm thick GdYBCO film prepared the reel-to-reel way has reached 3.2 MA cm-2 (77 K, 0 T).

Combined bioaugmentation with anaerobic ruminal fungi and fermentative bacteria to enhance biogas production from wheat straw and mushroom spent straw.

PubMed

Ferraro, Alberto; Dottorini, Giulia; Massini, Giulia; Mazzurco Miritana, Valentina; Signorini, Antonella; Lembo, Giuseppe; Fabbricino, Massimiliano

2018-07-01

Bioaugmentation with anaerobic ruminal fungi and a pool of hydrogen-producing fermenting bacteria was tested on wheat straw (WS) and mushroom spent straw (MSS) with the aim of improving anaerobic digestion performance. Batch tests were set up to simulate a Bioaugmentation Anaerobic Digestion (BAD) treatment comparing single- (I-BAD) and two-stage (II-BAD) process configurations, at two reactor scales, 120 and 1200 ml (×10). In both cases, higher CH 4 cumulative production was obtained in the II-BAD configuration on WS (65.1 ± 8.9 Nml and 922 ± 73.8 Nml respectively). The II-BADx10 tests allowed increasing CH 4 production (≃290% and ≃330% on WS and MSS, respectively) when compared to the unaugmented condition. Final results highlighted the achievable advantages of the two stage configuration in terms of CH 4 production enhancement. Microbial community investigations confirmed the efficiency of the bioaugmentation treatment and revealed that such a result was mainly related to the Methanosarcinales increase, mostly composed by Methanosaeta. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of fiber orientation on the failure behavior of a glass-fiber reinforced thermoplastic composite

NASA Astrophysics Data System (ADS)

Liang, Jiaai; Kalyanasundaram, Shankar

2017-05-01

In this study, hour-glass specimens made of a glass-fiber reinforced polypropylene composite with different fiber orientations were stamp formed in an open die. Strains on the surfaces of these specimens were recorded by a 3D photogrammetric measurement system. Specimens were cut into the designed shapes with two different fiber orientations [0°/90° and 45°/45°]. Based on the forming limit diagrams drawn for these material systems, it is found that change in fiber orientation induces change in deformation mode and different forming limit in strains.

A GIS-Interface Web Site: Exploratory Learning for Geography Curriculum

ERIC Educational Resources Information Center

Huang, Kuo Hung

2011-01-01

Although Web-based instruction provides learners with sufficient resources for self-paced learning, previous studies have confirmed that browsing navigation-oriented Web sites possibly hampers users' comprehension of information. Web sites designed as "categories of materials" for navigation demand more cognitive effort from users to orient their…

Graphoepitaxy by encapsulation

DOEpatents

Geis, M.W.; Smith, H.I.; Antoniadis, D.A.; Flanders, D.C.

1986-01-21

Improvements on the graphoepitaxial process for obtaining epitaxial or preferred orientation films are described wherein a cap of material is formed over the film to be oriented, artificial surface-relief structure may be present in the substrate, the cap, or both, and the film may be heated by irradiation with electromagnetic radiation. 13 figs.

Predicting Undergraduate Leadership Student Goal Orientation Using Personality Traits

ERIC Educational Resources Information Center

Lamm, Kevan W.; Sheikh, Emana; Carter, Hannah S.; Lamm, Alexa J.

2017-01-01

Finding strategies to increase the motivation of students, their connection with the material, and retention of the content, has been very important within leadership education. Previous research studies have shown that personality traits can predict desired outcomes, including goal orientation or motivational disposition. However, there have not…

Determinants of Academic Achievement: The Interaction of Children's Achievement Orientations with Skill Area.

ERIC Educational Resources Information Center

Licht, Barbara G.; Dweck, Carol S.

1984-01-01

Examines the degree to which experiencing confusion during the acquisition of new academic material differentially affects classroom performance of helpless and mastery-oriented fifth-graders. Provides an initial test of a theoretical approach to understanding differences between male and female performances in different subject areas. (AS)

Value Orientations and the Effects of Professional Schools on Students.

ERIC Educational Resources Information Center

Forsyth, Patrick B.; Danisiewicz, Thomas J.

The extent to which value orientations of professional students differ by occupational groups and by the socializing effects of professional schools on students was assessed. Approximately 1,150 students in nine major doctoral-granting universities participated. Based on work by Bengtson (1975), a humanism/materialism score was constructed for…

Z-direction fiber orientation in paperboard

Treesearch

John M. Considine; David W. Vahey; Roland Gleisner; Alan Rudie; Sabine Rolland du Roscoat; Jean-Francis Bloch

2010-01-01

This work evaluated the use of conventional tests to show beneficial attributes of z-direction fiber orientation (ZDFO) for structural paperboards. A survey of commercial linerboards indicated the presence of ZDFO in one material that had higher Taber stiffness, out-of-plane shear strength, directional dependence of Scott internal bond strength and directional...

Mineralogy and petrology of the Abee enstatite chondrite breccia and its dark inclusions

NASA Technical Reports Server (NTRS)

Rubin, A. E.; Keil, K.

1983-01-01

A model is proposed for the petrogenesis of the Abee E4 enstatite chondrite breccia, which consists of clasts, dark inclusions and matrix, and whose dark inclusions are an unusual kind of enstatite chondritic material. When the maximum metamorphic temperature of the breccia parent material was greater than 840 C, euhedral enstatite crystals in metallic Fe, Ni, and sulfide-rich areas grew into pliable metal and sulfide. Breccia parent material was impact-excavated, admixed with dark inclusions, and rapidly cooled. During this cooling, the clast and matrix material acquired thermal remanent magnetization. A subsequent ambient magnetic field imparted a uniform net magnetic orientation to the matrix and caused the magnetic orientation of the clasts to be less random. The Abee breccia was later consolidated by shock or by shallow burial and long period, low temperature metamorphism.

Predicting the Influence of Nano-Scale Material Structure on the In-Plane Buckling of Orthotropic Plates

NASA Technical Reports Server (NTRS)

Gates, Thomas S.; Odegard, Gregory M.; Nemeth, Michael P.; Frankland, Sarah-Jane V.

2004-01-01

A multi-scale analysis of the structural stability of a carbon nanotube-polymer composite material is developed. The influence of intrinsic molecular structure, such as nanotube length, volume fraction, orientation and chemical functionalization, is investigated by assessing the relative change in critical, in-plane buckling loads. The analysis method relies on elastic properties predicted using the hierarchical, constitutive equations developed from the equivalent-continuum modeling technique applied to the buckling analysis of an orthotropic plate. The results indicate that for the specific composite materials considered in this study, a composite with randomly orientated carbon nanotubes consistently provides the highest values of critical buckling load and that for low volume fraction composites, the non-functionalized nanotube material provides an increase in critical buckling stability with respect to the functionalized system.

Bonded half planes containing an arbitrarily oriented crack

NASA Technical Reports Server (NTRS)

Erdogan, F.; Aksogan, O.

1973-01-01

The plane elastostatic problem for two bonded half planes containing an arbitrarily oriented crack in the neighborhood of the interface is considered. Using Mellin transforms, the problem is formulated as a system of singular integral equations. The equations are solved for various crack orientations, material combinations, and external loads. The numerical results given include the stress intensity factors, tHe strain energy release rates, and tHe probable cleavage angles giving the direction of crack propagation.

A Limited Dynamic Investigation of Magnesium Alloy AZ31B in 3 Orientations

DTIC Science & Technology

2016-09-01

YYYY) September 2016 2. REPORT TYPE Technical Report 3. DATES COVERED (From - To) 1 August 2014–31 December 2015 4. TITLE AND SUBTITLE A ...ARL-TR-7807 ● SEP 2016 US Army Research Laboratory A Limited Dynamic Investigation of Magnesium Alloy AZ31B in 3 Orientations...Laboratory A Limited Dynamic Investigation of Magnesium Alloy AZ31B in 3 Orientations by Tyrone L Jones Weapons and Materials Research Directorate

Ultrafast shock-induced orientation of polycrystalline films: Applications to high explosives

NASA Astrophysics Data System (ADS)

Franken, Jens; Hambir, Selezion A.; Dlott, Dana D.

1999-02-01

Tiny laser-driven shock waves of ˜5 GPa pressure (nanoshocks) are used to study fast mechanical processes occurring in a thin layer of polycrystalline insensitive energetic material, (3-nitro-1,2,4-triazol-5-one) (NTO). Ultrafast coherent Raman spectroscopy of shocked NTO shows the existence of three distinct mechanical processes. Very fast (˜600 ps) changes in intensity and the appearance of new transitions are associated with the uniaxial nature of compression by the shock front. Frequency shifting and broadening processes which track the ˜2 ns duration nanoshock are associated with transient changes in density and temperature. A novel slower process (5-10 ns) starts as the shock begins to unload, and continues for several nanoseconds after the shock is over, resulting in changes of widths and intensities of several vibrational transitions. By comparing ultrafast spectra to static Raman spectra of single NTO crystals in various orientations, it is concluded that this process involves shock-induced partial orientation of the crystals in the NTO layer. The NTO crystals are oriented faster than the time scale for initiating chemical reactions. The sensitivity of explosive crystals to shock initiation may depend dramatically on the orientation of the crystal relative to the direction of shock propagation, so the implications of fast shock-induced orientation for energetic materials initiation are discussed briefly.

Florida Driver Education Handbook.

ERIC Educational Resources Information Center

Mick, Susan H.

This student edition contains the same basic information as the official Florida Driver Handbook, but the reading difficulty of the material has been sharply reduced. It also provides activity-oriented exercises and review tests on this material. Introductory materials include a complete listing of all activities given, some vocabulary exercises…

Cultural Literacy Based Critical Reading Teaching Material with Active Reader Strategy for Junior High School

ERIC Educational Resources Information Center

Damaianti, Vismaia S.; Damaianti, Lira Fessia; Mulyati, Yeti

2017-01-01

This article describes the findings of a study aimed at producing a set of cultural literacy-oriented critical reading teaching material. This material is developed as a countermeasure to the increasingly thin sensitivity of society, especially the students toward noble values of religion, custom, and culture. With this material student get a…

SU-F-T-181: Proton Therapy Tissue-Equivalence of 3D Printed Materials

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

Taylor, P; Craft, D; Followill, D

Purpose: This work investigated the proton tissue-equivalence of various 3D printed materials. Methods: Three 3D printers were used to create 5 cm cubic phantoms made of different plastics with varying percentages of infill. White resin, polylactic acid (PLA), and NinjaFlex plastics were used. The infills ranged from 15% to 100%. Each phantom was scanned with a CT scanner to obtain the HU value. The relative linear stopping power (RLSP) was then determined using a multi-layer ion chamber in a 200 MeV proton beam. The RLSP was measured both parallel and perpendicular to the print direction for each material. Results: Themore » HU values of the materials ranged from lung-equivalent (−820 HU σ160) when using a low infill, to soft-tissue-equivalent 159 (σ12). The RLSP of the materials depended on the orientation of the beam relative to the print direction. When the proton beam was parallel to the print direction, the RLSP was generally higher than the RLSP in the perpendicular orientation, by up to 45%. This difference was smaller (less than 6%) for the materials with 100% infill. For low infill cubes irradiated parallel to the print direction, the SOBP curve showed extreme degradation of the beam in the distal region. The materials with 15–25% infill had wide-ranging agreement with a clinical HU-RLSP conversion curve, with some measurements falling within 1% of the curve and others deviating up to 45%. The materials with 100% infill all fell within 7% of the curve. Conclusion: While some materials tested fall within 1% of a clinical HU-RLSP curve, caution should be taken when using 3D printed materials with proton therapy, as the orientation of the beam relative to the print direction can result in a large change in RLSP. Further investigation is needed to measure how the infill pattern affects the material RLSP. This work was supported by PHS grant CA180803.« less

Top-Level Categories of Constitutively Organized Material Entities - Suggestions for a Formal Top-Level Ontology

PubMed Central

Vogt, Lars; Grobe, Peter; Quast, Björn; Bartolomaeus, Thomas

2011-01-01

Background Application oriented ontologies are important for reliably communicating and managing data in databases. Unfortunately, they often differ in the definitions they use and thus do not live up to their potential. This problem can be reduced when using a standardized and ontologically consistent template for the top-level categories from a top-level formal foundational ontology. This would support ontological consistency within application oriented ontologies and compatibility between them. The Basic Formal Ontology (BFO) is such a foundational ontology for the biomedical domain that has been developed following the single inheritance policy. It provides the top-level template within the Open Biological and Biomedical Ontologies Foundry. If it wants to live up to its expected role, its three top-level categories of material entity (i.e., ‘object’, ‘fiat object part’, ‘object aggregate’) must be exhaustive, i.e. every concrete material entity must instantiate exactly one of them. Methodology/Principal Findings By systematically evaluating all possible basic configurations of material building blocks we show that BFO's top-level categories of material entity are not exhaustive. We provide examples from biology and everyday life that demonstrate the necessity for two additional categories: ‘fiat object part aggregate’ and ‘object with fiat object part aggregate’. By distinguishing topological coherence, topological adherence, and metric proximity we furthermore provide a differentiation of clusters and groups as two distinct subcategories for each of the three categories of material entity aggregates, resulting in six additional subcategories of material entity. Conclusions/Significance We suggest extending BFO to incorporate two additional categories of material entity as well as two subcategories for each of the three categories of material entity aggregates. With these additions, BFO would exhaustively cover all top-level types of material entity that application oriented ontologies may use as templates. Our result, however, depends on the premise that all material entities are organized according to a constitutive granularity. PMID:21533043

Aging and the Haptic Perception of Material Properties.

PubMed

Norman, J Farley; Adkins, Olivia C; Hoyng, Stevie C; Dowell, Catherine J; Pedersen, Lauren E; Gilliam, Ashley N

2016-12-01

The ability of 26 younger (mean age was 22.5 years) and older adults (mean age was 72.6 years) to haptically perceive material properties was evaluated. The participants manually explored (for 5 seconds) 42 surfaces twice and placed each of these 84 experimental stimuli into one of seven categories: paper, plastic, metal, wood, stone, fabric, and fur/leather. In general, the participants were best able to identify fur/leather and wood materials; in contrast, recognition performance was worst for stone and paper. Despite similar overall patterns of performance for younger and older participants, the younger adults' recognition accuracies were 26.5% higher. The participants' tactile acuities (assessed by tactile grating orientation discrimination) affected their ability to identify surface material. In particular, the Pearson r correlation coefficient relating the participants' grating orientation thresholds and their material identification performance was -0.8: The higher the participants' thresholds, the lower the material recognition ability. While older adults are able to effectively perceive the solid shape of environmental objects using the sense of touch, their ability to perceive surface materials is significantly compromised.

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

Canevarolo, Sebastião V., E-mail: caneva@ufscar.br; Ravazzi, Camila; Silva, Jorge, E-mail: jorge.silva@ufscar.br

Polyethylene films are a common packaging material. The level and type of chain orientation in these films are a very important property which is of great care and concern of the converter personnel during the conformation process. Usually bi-orientation is the conventional procedure but when easy tear in one direction is needed mono-orientation is sought. This paper deal with the characterization of the crystalline orientation in films of polyethylene blends (HDPE/LLDPE) which have being oriented in two steps: initially the polymer was bi-oriented via extrusion-blown, cooled, and then in a second process hot stretched along the machine direction in ordermore » to produce mono-oriented films. In order to evaluate the orientation of the film, the polarization of the FT-IR beam was rotated 360° in steps of 5° by rotating the polarizer. In each step the absorbance spectrum was recorded and the corresponding dichroic ratio (DR) calculated after subtracting the baseline. With differential scanning calorimetry (DSC) was possible to infer about the changes in the morphology caused by the stretching.« less

The effect of orientation difference in fused deposition modeling of ABS polymer on the processing time, dimension accuracy, and strength

NASA Astrophysics Data System (ADS)

Tanoto, Yopi Y.; Anggono, Juliana; Siahaan, Ian H.; Budiman, Wesley

2017-01-01

There are several parameters that must be set before manufacturing a product using 3D printing. These parameters include the orientation deposition of that product, type of material, form fill, fill density, and other parameters. The finished product of 3D printing has some responses that can be observed, measured, and tested. Some of those responses are the processing time, the dimensions of the end product, its surface roughness and the mechanical properties, i.e. its yield strength, ultimate tensile strength, and impact resistance. This research was conducted to study the relationship between process parameters of 3D printing machine using a technology of fused deposition modeling (FDM) and the generated responses. The material used was ABS plastic that was commonly used in the industry. Understanding the relationship between the parameters and the responses thus the resulting product can be manufactured to meet the user needs. Three different orientations in depositing the ABS polymer named XY(first orientation), YX (second orientation), and ZX (third orientation) were studied. Processing time, dimensional accuracy, and the product strength were the responses that were measured and tested. The study reports that the printing process with third orientation was the fastest printing process with the processing time 2432 seconds followed by orientation 1 and 2 with a processing time of 2688 and 2780 seconds respectively. Dimension accuracy was also measured from the width and the length of gauge area of tensile test specimens printed in comparison with the dimensions required by ASTM 638-02. It was found that the smallest difference was in thickness dimension, i.e. 0.1 mm thicker in printed sample using second orientation than as required by the standard. The smallest thickness deviation from the standard was measured in width dimension of a sample printed using first orientation (0.13 mm). As with the length dimension, the closest dimension to the standard was resulted from the third orientation product, i.e 0.2 mm. Tensile test done on all the specimens produced with those three orientations shows that the highest tensile strength was obtained in sample from second orientation deposition, i.e. 7.66 MPa followed by the first and third orientations products, i.e. 6.8 MPa and 3.31 MPa, respectively.

Sidewall tensiometer and method of determining soil moisture potential in below-grade earthen soil

DOEpatents

Hubbell, Joel M.; Sisson, James B.

2001-01-01

A sidewall tensiometer to in situ determine below-grade soil moisture potential of earthen soil includes, a) a body adapted for insertion into an opening in earthen soil below grade, the body having lateral sidewalls; b) a laterally oriented porous material provided relative to the body lateral sidewalls, the laterally oriented porous material at least in part defining a fluid chamber within the body; c) a pressure a sensor in fluid communication with the fluid chamber; and d) sidewall engaging means for engaging a portion of a sidewall of an earth opening to laterally urge the porous material into hydraulic communication with earthen soil of another portion of the opening sidewall. Methods of taking tensiometric measurements are also disclosed.

Tapered bed bioreactor

DOEpatents

Scott, Charles D.; Hancher, Charles W.

1977-01-01

A vertically oriented conically shaped column is used as a fluidized bed bioreactor wherein biologically catalyzed reactions are conducted in a continuous manner. The column utilizes a packing material a support having attached thereto a biologically active catalytic material.

49 CFR 178.337-2 - Material.

Code of Federal Regulations, 2010 CFR

2010-10-01

... basis. A lot is defined as 100 tons or less of the same heat treatment processing lot having a thickness... Transportation. (4) The direction of final rolling of the shell material shall be the circumferential orientation...

SCC of Alloy 690 and its Weld Metals

NASA Astrophysics Data System (ADS)

Andresen, Peter L.; Morra, Martin M.; Ahluwalia, Kawaljit

Alloy 690 base metal, HAZ and weld metal were tested in representative PWR primary water at 290 to 360°C. Intergranular cracking was observed in all materials. Growth rates as high as 1.2 × 10-6 mm/s were observed in the S-L orientation with micro structural banded material after cold rolling or forging to align the planes of banding, rolling and cracking. However, not all banded material has exhibited such high growth rates. Growth rates on homogeneous Alloy 690, including extruded CRDM tubing, often showed growth rates in the range of 2 - 8 × 10-8 mm/s in cold worked condition and an S-L orientation. Crack growth rates in some Alloy 690 tests were in the range of 1 to 10 × 10-9 mm/s, primarily in orientations other than S-L. For cracks aligned along the HAZ, growth rates as high as 1.2 × 10-8 mm/s were observed. Alloy 152/52/52i weld metals always exhibited low growth rates, apart from a weld that was further cold worked by 20%, which grew at 7 × 10-9 mm/s.

Effect of crystallographic orientations of grains on the global mechanical properties of steel sheets by depth sensing indentation

NASA Astrophysics Data System (ADS)

Burik, P.; Pesek, L.; Kejzlar, P.; Andrsova, Z.; Zubko, P.

2017-01-01

The main idea of this work is using a physical model to prepare a virtual material with required properties. The model is based on the relationship between the microstructure and mechanical properties. The macroscopic (global) mechanical properties of steel are highly dependent upon microstructure, crystallographic orientation of grains, distribution of each phase present, etc... We need to know the local mechanical properties of each phase separately in multiphase materials. The grain size is a scale, where local mechanical properties are responsible for the behavior. Nanomechanical testing using depth sensing indentation (DSI) provides a straightforward solution for quantitatively characterizing each of phases in microstructure because it is very powerful technique for characterization of materials in small volumes. The aim of this experimental investigation is: (i) to prove how the mixing rule works for local mechanical properties (indentation hardness HIT) in microstructure scale using the DSI technique on steel sheets with different microstructure; (ii) to compare measured global properties with properties achieved by mixing rule; (iii) to analyze the effect of crystallographic orientations of grains on the mixing rule.

Polymerization and processing of polymers in magnetic fields

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

Benicewicz, B.C.; Smith, M.E.; Douglas, E.P.

1997-04-01

Liquid crystalline thermosets (LCT`s) have become recognized over the past few years as an important class of materials. Numerous reports from the authors laboratory and others have described their synthesis and phase behavior. In particular, the authors have described important effects due to the orientation of the rodlike molecules in a liquid crystalline phase. They have found that curing rates are enhanced compared to reaction in an isotropic phase, and that the glass transition of the fully cured material can be significantly higher than the final cure temperature. For structural applications, orientation of LCT`s will allow maximum improvement in mechanicalmore » properties. A few studies have described use of magnetic fields to orient LCT`s. However, no measurements were made of the tensile properties of materials processed in magnetic fields. The authors have conducted experiments which describe the tensile modulus dependence of an LCT over the complete range of magnetic field strengths from 0 to 18 Tesla. Their work has focused on the system composed of the diglycidyl ether of dihydroxy-{alpha}-methylstilbene (DGE-DHAMS) cured with sulfanilamide (SAA).« less

32 CFR 705.6 - Releasing public information material to the media.

Code of Federal Regulations, 2014 CFR

2014-07-01

... media. 705.6 Section 705.6 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY... information material to the media. (a) Methods of releasing information: (1) Release at the seat of government... information is released to media: (1) Navy oriented information material (written, taped, motion picture...

32 CFR 705.6 - Releasing public information material to the media.

Code of Federal Regulations, 2013 CFR

2013-07-01

... media. 705.6 Section 705.6 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY... information material to the media. (a) Methods of releasing information: (1) Release at the seat of government... information is released to media: (1) Navy oriented information material (written, taped, motion picture...

32 CFR 705.6 - Releasing public information material to the media.

Code of Federal Regulations, 2012 CFR

2012-07-01

... media. 705.6 Section 705.6 National Defense Department of Defense (Continued) DEPARTMENT OF THE NAVY... information material to the media. (a) Methods of releasing information: (1) Release at the seat of government... information is released to media: (1) Navy oriented information material (written, taped, motion picture...

Mechanical properties of wood-based composite materials

Treesearch

Zhiyong Cai; Robert J. Ross

2010-01-01

The term composite is used to describe any wood material bonded together with adhesives. The current product mix ranges from fiberboard to laminated beams and components. In this chapter, wood-based composite materials are classified into the following categories: panel products (plywood, oriented strandboard (OSB), particleboard, fiberboard, medium-density fiberboard...

Energy-selective Neutron Imaging for Three-dimensional Non-destructive Probing of Crystalline Structures

NASA Astrophysics Data System (ADS)

Peetermans, S.; Bopp, M.; Vontobel, P.; Lehmann, E. H.

Common neutron imaging uses the full polychromatic neutron beam spectrum to reveal the material distribution in a non-destructive way. Performing it with a reduced energy band, i.e. energy-selective neutron imaging, allows access to local variation in sample crystallographic properties. Two sample categories can be discerned with different energy responses. Polycrystalline materials have an energy-dependent cross-section featuring Bragg edges. Energy-selective neutron imaging can be used to distinguish be- tween crystallographic phases, increase material sensitivity or penetration, improve quantification etc. An example of the latter is shown by the examination of copper discs prior to machining them into linear accelerator cavity structures. The cross-section of single crystals features distinct Bragg peaks. Based on their pattern, one can determine the orientation of the crystal, as in a Laue pattern, but with the tremendous advantage that the operation can be performed for each pixel, yielding crystal orientation maps at high spatial resolution. A wholly different method to investigate such samples is also introduced: neutron diffraction imaging. It is based on projections formed by neutrons diffracted from the crystal lattice out of the direct beam. The position of these projections on the detector gives information on the crystal orientation. The projection itself can be used to reconstruct the crystal shape. A three-dimensional mapping of local Bragg reflectivity or a grain orientation mapping can thus be obtained.

Effect of collagen fibre orientation on intervertebral disc torsion mechanics.

PubMed

Yang, Bo; O'Connell, Grace D

2017-12-01

The intervertebral disc is a complex fibro-cartilaginous material, consisting of a pressurized nucleus pulposus surrounded by the annulus fibrosus, which has an angle-ply structure. Disc injury and degeneration are noted by significant changes in tissue structure and function, which significantly alters stress distribution and disc joint stiffness. Differences in fibre orientation are thought to contribute to changes in disc torsion mechanics. Therefore, the objective of this study was to evaluate the effect of collagen fibre orientation on internal disc mechanics under compression combined with axial rotation. We developed and validated a finite element model (FEM) to delineate changes in disc mechanics due to fibre orientation from differences in material properties. FEM simulations were performed with fibres oriented at [Formula: see text] throughout the disc (uniform by region and fibre layer). The initial model was validated by published experimental results for two load conditions, including [Formula: see text] axial compression and [Formula: see text] axial rotation. Once validated, fibre orientation was rotated by [Formula: see text] or [Formula: see text] towards the horizontal plane, resulting in a decrease in disc joint torsional stiffness. Furthermore, we observed that axial rotation caused a sinusoidal change in disc height and radial bulge, which may be beneficial for nutrient transport. In conclusion, including anatomically relevant fibre angles in disc joint FEMs is important for understanding stress distribution throughout the disc and will be important for understanding potential causes for disc injury. Future models will include regional differences in fibre orientation to better represent the fibre architecture of the native disc.

Relationship between Lifestyle Values and Achievement Goal Orientation among Vocational Students in Thailand

ERIC Educational Resources Information Center

Chantara, Soontornpathai; Koul, Ravinder; Kaewkuekool, Sittichai

2014-01-01

This study brings models of value theory and motivational goal theory together to investigate the relationship between lifestyle values (materialism, religiosity, physical well-being and image) and achievement goal orientation of college students enrolled in vocational programmes in Thailand (N?=?1670, males?=?38.5% and females?=?61.5%). We found…

Orientation to Machine Shop. Safety, Machine Identification, Metal Identification.

ERIC Educational Resources Information Center

Engelbrecht, Nancy; And Others

These instructional materials provide an orientation to the machine shop for use at the postsecondary level. The first of three sections discusses four important areas of safety: (1) personal safety; (2) safety procedures; (3) safe work practices; and (4) fire prevention. The second section identifies and describes the general purposes of 12…

Graphic Arts: Book One. Orientation, Composition, and Paste-up.

ERIC Educational Resources Information Center

Farajollahi, Karim; And Others

The first of a three-volume set of instructional materials for a graphic arts course, this manual consists of 13 instructional units. Covered in the units are orientation (career overview, shop safety, shop organization, photo-offset theory, legal restrictions, and applying for a job); principles of copy planning (overview of copy planning and…

Graphic Arts: Orientation, Composition, and Paste-Up. Third Edition.

ERIC Educational Resources Information Center

Crummett, Dan

This document contains teacher and student materials for a course in graphic arts. Ten units of instruction cover the following topics: (1) orientation; (2) shop safety; (3) shop organization; (4) printing processes; (5) paper; (6) typography; (7) typesetting; (8) design principles; (9) paste-up principles and procedures; and (10) proof procedures…

Graphic Arts: Orientation, Composition, and Paste-Up. Fourth Edition. Teacher Edition [and] Student Edition.

ERIC Educational Resources Information Center

Licklider, Cheryl

This teacher and student edition, the first in a series of instructional materials on graphic communication, consists of orientation information, teacher pages, and student worksheets. The teacher edition contains these introductory pages: use of this publication; training and competency profile; PrintED crosswalk; instructional/task analysis;…

The Effects of a Behaviorally Oriented Tenth Grade Nutrition Curriculum.

ERIC Educational Resources Information Center

Flora, June A.; And Others

Two studies examined the impact of a five-session behaviorally oriented nutrition curriculum on health knowledge, behavioral intentions, attitudes, and self-reported behavior of tenth grade students. The first study examined the impact of a nutrition curriculum when combined with materials for the family and the impact of the curriculum when…

Aerospace-Oriented Units for Use in Secondary School Classes.

ERIC Educational Resources Information Center

Williams, Mary H.; And Others

This set of nine units is intended to furnish aerospace-oriented resource material to help teachers include recent scientific and technological advances in the secondary school science curriculum. The units provided are as follows: history of astronomy, the solar system, beyond the solar system, history of flight, spaceflight facts, aerology,…

Block Copolymer Directed Biomimetic Mineral Formation for Polymer Nanocomposites

NASA Astrophysics Data System (ADS)

Gleeson, Sarah; Yu, Tony; Chen, Xi; Marcolongo, Michele; Li, Christopher

Bone is a hierarchically structured biocomposite comprised of mineralized collagen fibrils. The mechanical properties of bone can be precisely tuned by the structure and morphology of the mineral nanocrystals as well as the organic collagen fibrils. Synthetic materials that can mimic the nanostructure of natural bone show promise to replicate bone's structural function, yet little is known about the mechanism of mineral formation. We previously have shown that hierarchically ordered polymer fibers control the distribution and orientation of hydroxyapatite, enhancing mechanical properties and biocompatibility. We demonstrate a new method for mineralization by forming block copolymer single crystal films of polycaprolactone-block-poly(acrylic acid) (PCL- b-PAA) so that lamellar anionic PAA nanodomains recruit mineral ions and provide one-dimensional confinement to induce orientation. The effect of the anionic domain dimensions on mineral content, orientation, and structure within the polymer matrix is shown. The mechanical properties of the nanocomposite are evaluated to determine the role of mineral orientation and crystallinity in composite strength. These results can be used to tailor the physical mineralization environment to create a more biomimetic bone material.

Unit-Sphere Anisotropic Multiaxial Stochastic-Strength Model Probability Density Distribution for the Orientation of Critical Flaws

NASA Technical Reports Server (NTRS)

Nemeth, Noel

2013-01-01

Models that predict the failure probability of monolithic glass and ceramic components under multiaxial loading have been developed by authors such as Batdorf, Evans, and Matsuo. These "unit-sphere" failure models assume that the strength-controlling flaws are randomly oriented, noninteracting planar microcracks of specified geometry but of variable size. This report develops a formulation to describe the probability density distribution of the orientation of critical strength-controlling flaws that results from an applied load. This distribution is a function of the multiaxial stress state, the shear sensitivity of the flaws, the Weibull modulus, and the strength anisotropy. Examples are provided showing the predicted response on the unit sphere for various stress states for isotropic and transversely isotropic (anisotropic) materials--including the most probable orientation of critical flaws for offset uniaxial loads with strength anisotropy. The author anticipates that this information could be used to determine anisotropic stiffness degradation or anisotropic damage evolution for individual brittle (or quasi-brittle) composite material constituents within finite element or micromechanics-based software

3D DDD modelling of dislocation-precipitate interaction in a nickel-based single crystal superalloy under cyclic deformation

NASA Astrophysics Data System (ADS)

Lin, Bing; Huang, Minsheng; Zhao, Liguo; Roy, Anish; Silberschmidt, Vadim; Barnard, Nick; Whittaker, Mark; McColvin, Gordon

2018-06-01

Strain-controlled cyclic deformation of a nickel-based single crystal superalloy has been modelled using three-dimensional (3D) discrete dislocation dynamics (DDD) for both [0 0 1] and [1 1 1] orientations. The work focused on the interaction between dislocations and precipitates during cyclic plastic deformation at elevated temperature, which has not been well studied yet. A representative volume element with cubic γ‧-precipitates was chosen to represent the material, with enforced periodical boundary conditions. In particular, cutting of superdislocations into precipitates was simulated by a back-force method. The global cyclic stress-strain responses were captured well by the DDD model when compared to experimental data, particularly the effects of crystallographic orientation. Dislocation evolution showed that considerably high density of dislocations was produced for [1 1 1] orientation when compared to [0 0 1] orientation. Cutting of dislocations into the precipitates had a significant effect on the plastic deformation, leading to material softening. Contour plots of in-plane shear strain proved the development of heterogeneous strain field, resulting in the formation of shear-band embryos.

Oriented antibody immobilization to polystyrene macrocarriers for immunoassay modified with hydrazide derivatives of poly(meth)acrylic acid

PubMed Central

Shmanai, Vadim V; Nikolayeva, Tamara A; Vinokurova, Ludmila G; Litoshka, Anatoli A

2001-01-01

Background Hydrophobic polystyrene is the most common material for solid phase immunoassay. Proteins are immobilized on polystyrene by passive adsorption, which often causes considerable denaturation. Biological macromolecules were found to better retain their functional activity when immobilized on hydrophilic materials. Polyacrylamide is a common material for solid-phase carriers of biological macromolecules, including immunoreagents used in affinity chromatography. New macroformats for immunoassay modified with activated polyacrylamide derivatives seem to be promising. Results New polymeric matrices for immunoassay in the form of 0.63-cm balls which contain hydrazide functional groups on hydrophilic polymer spacer arms at their surface shell are synthesized by modification of aldehyde-containing polystyrene balls with hydrazide derivatives of poly(meth)acrylic acid. The beads contain up to 0.31 μmol/cm2 active hydrazide groups accessible for covalent reaction with periodate-oxidized antibodies. The matrices obtained allow carrying out the oriented antibody immobilization, which increases the functional activity of immunosorbents. Conclusions An efficient site-directed antibody immobilization on a macrosupport is realized. The polymer hydrophilic spacer arms are the most convenient and effective tools for oriented antibody coupling with molded materials. The suggested scheme can be used for the modification of any other solid supports containing electrophilic groups reacting with hydrazides. PMID:11545680

Thermal and Structural Analysis of a Hollow Core Space Shuttle Main Engine (SSME) Turbine Blade

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Kalluri, Sreeramesh; McGaw, Michael A.

1995-01-01

The influence of primary and secondary orientations on the elastic response of a hollow core, (001)-oriented nickel base single-crystal superalloy turbine blade, was investigated under combined thermal and mechanical conditions. Finite element techniques is employed through MARC finite element code to conduct the analyses on a hollow core SSME turbine blade made out of PWA 1480 single crystal material. Primary orientation of the single crystal superalloy was varied in increments of 2 deg, from 0 to 10 deg, from the (001) direction. Two secondary orientations (0 and 45 deg) were considered with respect to the global coordinate system, as the primary orientation angle was varied. The stresses developed within the single crystal blade were determined for different orientations of the blade. The influence of angular offsets such as the single crystal's primary and secondary orientations and the loading conditions on the elastic stress response of the PWA 1480 hollow blade are summarized. The influence of he primary orientation angle, when constrained between the bounds considered, was not found to be as significant as the influence of the secondary orientation angle.

The influence of primary and secondary orientations on the elastic response of a nickel-base single-crystal superalloy

NASA Technical Reports Server (NTRS)

Abdul-Aziz, Ali; Kalluri, Sreeramesh; Mcgaw, Michael A.

1993-01-01

The influence of primary orientation on the elastic response of a (001)-oriented nickel-base single-crystal superalloy, PWA 1480, was investigated under mechanical, thermal, and combined thermal and mechanical loading conditions using finite element techniques. Elastic stress analyses were performed using the MARC finite element code on a square plate of PWA 1480 material. Primary orientation of the single crystal superalloy was varied in increments of 2 deg, from 0 to 10 deg, from the (001) direction. Two secondary orientations (0 and 45 deg) were considered, with respect to the global coordinate system, as the primary orientation angle was varied. The stresses developed within the single crystal plate were determined for each loading condition. In this paper, the influence of the angular offset between the primary crystal orientation and the loading direction on the elastic stress response of the PWA 1480 plate is presented for different loading conditions. The influence of primary orientation angle, when constrained between the bounds considered, was not found to be as significant as the influence of the secondary orientation angle, which is not typically controlled.

Molecular Orientation in Two Component Vapor-Deposited Glasses: Effect of Substrate Temperature and Molecular Shape

NASA Astrophysics Data System (ADS)

Powell, Charles; Jiang, Jing; Walters, Diane; Ediger, Mark

Vapor-deposited glasses are widely investigated for use in organic electronics including the emitting layers of OLED devices. These materials, while macroscopically homogenous, have anisotropic packing and molecular orientation. By controlling this orientation, outcoupling efficiency can be increased by aligning the transition dipole moment of the light-emitting molecules parallel to the substrate. Light-emitting molecules are typically dispersed in a host matrix, as such, it is imperative to understand molecular orientation in two-component systems. In this study we examine two-component vapor-deposited films and the orientations of the constituent molecules using spectroscopic ellipsometry, UV-vis and IR spectroscopy. The role of temperature, composition and molecular shape as it effects molecular orientation is examined for mixtures of DSA-Ph in Alq3 and in TPD. Deposition temperature relative to the glass transition temperature of the two-component mixture is the primary controlling factor for molecular orientation. In mixtures of DSA-Ph in Alq3, the linear DSA-Ph has a horizontal orientation at low temperatures and slight vertical orientation maximized at 0.96Tg,mixture, analogous to one-component films.

Effect of horizontal molecular orientation on triplet-exciton diffusion in amorphous organic films

NASA Astrophysics Data System (ADS)

Sawabe, T.; Takasu, I.; Yonehara, T.; Ono, T.; Yoshida, J.; Enomoto, S.; Amemiya, I.; Adachi, C.

2012-09-01

Triplet harvesting is a candidate technology for highly efficient and long-life white OLEDs, where green or red phosphorescent emitters are activated by the triplet-excitons diffused from blue fluorescent emitters. We examined two oxadiazole-based electron transport materials with different horizontal molecular orientation as a triplet-exciton diffusion layer (TDL) in triplet-harvesting OLEDs. The device characteristics and the transient electroluminescent analyses of the red phosphorescent emitter showed that the triplet-exciton diffusion was more effective in the highly oriented TDL. The results are ascribed to the strong orbital overlap between the oriented molecules, which provides rapid electron exchange (Dexter energy transfer) in the TDL.

Unique system of FE/PD for magneto-optical recording and magnetic switching devices

DOEpatents

Liu, Chian Q.; Bader, Samuel D.

1992-01-01

A high density magneto-optical information storage medium utilizing the properties of an ultrathin iron film on a palladium substrate. The present invention comprises a magneto-optical medium capable of thermal and magnetic stability and capable of possessing a vertical orientation of the magnetization vector for the magnetic material. Data storage relies on the temperature dependence of the coercivity of the ultrathin film. Data retrieval derives from the Kerr effect which describes the direction of rotation of a plane of polarized light traversing the ultrathin magnetic material as a function of the orientation of the magnetization vector.

Performance-oriented packaging testing of PPP-B-601 ERAPS wood box for packing Group II solid hazardous material. Test report for Oct 91

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

Wu, E.

1991-10-01

Qualification tests were performed to determine whether the in-service PPP-B-601 ERAPS Wood Box could be utilized to contain properly dunnaged solid type hazardous materials weighing up to a gross weight of 237 kg (523 pounds). The tests were conducted in accordance with Performance Oriented Packaging (POP) requirements specified by the United Nations Recommendations on the Transportation of Dangerous Goods. The box has conformed to the POP performance requirements; i.e., the box successfully retained its contents throughout the stacking, vibration and drop tests.

Method for improving performance of high temperature superconductors within a magnetic field

DOEpatents

Wang, Haiyan; Foltyn, Stephen R.; Maiorov, Boris A.; Civale, Leonardo

2010-01-05

The present invention provides articles including a base substrate including a layer of an oriented cubic oxide material having a rock-salt-like structure layer thereon; and, a buffer layer upon the oriented cubic oxide material having a rock-salt-like structure layer, the buffer layer having an outwardly facing surface with a surface morphology including particulate outgrowths of from 10 nm to 500 run in size at the surface, such particulate outgrowths serving as flux pinning centers whereby the article maintains higher performance within magnetic fields than similar articles without the necessary density of such outgrowths.

Engineering Controlled Spalling in (100)-Oriented GaAs for Wafer Reuse

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

Sweet, Cassi A.; McNeely, Joshua E.; Gorman, Brian

Controlled spalling offers a way to cleave thin, single-crystal films or devices from wafers, particularly if the fracture planes in the material are oriented parallel to the wafer surface. Unfortunately, misalignment between the favored fracture planes and the wafer surface preferred for photovoltaic growth in (100)-oriented GaAs produces a highly faceted surface when subject to controlled spalling. This highly faceted cleavage surface is problematic in several ways: (1) it can result in large variations of spall depth due to unstable crack propagation; (2) it may introduce defects into the device zone or underlying substrate; and (3) it consumes many micronsmore » of material outside of the device zone. We present the ways in which we have engineered controlled spalling for (100)-oriented GaAs to minimize these effects. We expand the operational window for controlled spalling to avoid spontaneous spalling, find no evidence of dislocation activity in the spalled film or the parent wafer, and reduce facet height and facet height irregularity. Resolving these issues provides a viable path forward for reducing III-V device cost through the controlled spalling of (100)-oriented GaAs devices and subsequent wafer reuse when these processes are combined with a high-throughput growth method such as Hydride Vapor Phase Epitaxy.« less

Development of a test and flight engineering oriented language. Phase 3: Presentation

NASA Technical Reports Server (NTRS)

Kamsler, W. F.; Case, C. W.; Kinney, E. L.; Gyure, J.

1970-01-01

The format material used in an oral presentation of the phase 3 study effort is given. The material includes a description of the language ALOFT and a terminology comparison with other test languages.

Methods for controlling pore morphology in aerogels using electric fields and products thereof

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

Worsley, Marcus A.; Baumann, Theodore F.; Satcher, Jr., Joe H.

In one embodiment, an aerogel or xerogel includes column structures of a material having minor pores therein and major pores devoid of the material positioned between the column structures, where longitudinal axes of the major pores are substantially parallel to one another. In another embodiment, a method includes heating a sol including aerogel or xerogel precursor materials to cause gelation thereof to form an aerogel or xerogel and exposing the heated sol to an electric field, wherein the electric field causes orientation of a microstructure of the sol during gelation, which is retained by the aerogel or xerogel. In onemore » approach, an aerogel has elongated pores extending between a material arranged in column structures having structural characteristics of being formed from a sol exposed to an electric field that causes orientation of a microstructure of the sol during gelation which is retained by the elongated pores of the aerogel.« less

Controlled nanostructrures formation by ultra fast laser pulses for color marking.

PubMed

Dusser, B; Sagan, Z; Soder, H; Faure, N; Colombier, J P; Jourlin, M; Audouard, E

2010-02-01

Precise nanostructuration of surface and the subsequent upgrades in material properties is a strong outcome of ultra fast laser irradiations. Material characteristics can be designed on mesoscopic scales, carrying new optical properties. We demonstrate in this work, the possibility of achieving material modifications using ultra short pulses, via polarization dependent structures generation, that can generate specific color patterns. These oriented nanostructures created on the metal surface, called ripples, are typically smaller than the laser wavelength and in the range of visible spectrum. In this way, a complex colorization process of the material, involving imprinting, calibration and reading, has been performed to associate a priori defined colors. This new method based on the control of the laser-driven nanostructure orientation allows cumulating high quantity of information in a minimal surface, proposing new applications for laser marking and new types of identifying codes.

Catalytic Graphitization of Coal-Based Carbon Materials with Light Rare Earth Elements.

PubMed

Wang, Rongyan; Lu, Guimin; Qiao, Wenming; Yu, Jianguo

2016-08-30

The catalytic graphitization mechanism of coal-based carbon materials with light rare earth elements was investigated using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, selected-area electron diffraction, and high-resolution transmission electron microscopy. The interface between light rare earth elements and carbon materials was carefully observed, and two routes of rare earth elements catalyzing the carbon materials were found: dissolution-precipitation and carbide formation-decomposition. These two simultaneous processes certainly accelerate the catalytic graphitization of carbon materials, and light rare earth elements exert significant influence on the microstructure and thermal conductivity of graphite. Moreover, by virtue of praseodymium (Pr), it was found that a highly crystallographic orientation of graphite was induced and formed, which was reasonably attributed to the similar arrangements of the planes perpendicular to (001) in both graphite and Pr crystals. The interface between Pr and carbon was found to be an important factor for the orientation of graphite structure.

Research on the Mode of Technology Innovation Alliance of the New Material Industry in Hunan Province

NASA Astrophysics Data System (ADS)

Wang, Fan

2018-03-01

One of the main directions of technology development in the 21st century is the development and application of new materials, and the key to the development of the new material industry lies in the industrial technology innovation. The gross scale of the new material industry in Hunan Province ranks the first array in China. Based on the present situation of Hunan’s new material industry, three modes of technology innovation alliance are put forward in this paper, namely the government-driven mode, the research-driven and the market-oriented mode. The government-driven mode is applicable to the major technology innovation fields with uncertain market prospect, high risk of innovation and government’s direct or indirect intervention;the research-driven mode is applicable to the key technology innovation fields with a high technology content; and the market-oriented mode is applicable to the general innovation fields in which enterprises have demands for technology innovation but such innovation must be achieved via cooperative research and development.

Control method and system for use when growing thin-films on semiconductor-based materials

DOEpatents

McKee, Rodney A.; Walker, Frederick J.

2001-01-01

A process and system for use during the growth of a thin film upon the surface of a substrate by exposing the substrate surface to vaporized material in a high vacuum (HV) facility involves the directing of an electron beam generally toward the surface of the substrate as the substrate is exposed to vaporized material so that electrons are diffracted from the substrate surface by the beam and the monitoring of the pattern of electrons diffracted from the substrate surface as vaporized material settles upon the substrate surface. When the monitored pattern achieves a condition indicative of the desired condition of the thin film being grown upon the substrate, the exposure of the substrate to the vaporized materials is shut off or otherwise adjusted. To facilitate the adjustment of the crystallographic orientation of the film relative to the electron beam, the system includes a mechanism for altering the orientation of the surface of the substrate relative to the electron beam.

Erosion Results of the MISSE 7 Polymers Experiment and Zenith Polymers Experiment After 1.5 Years of Space Exposure

NASA Technical Reports Server (NTRS)

De Groh, Kim K.; Banks, Bruce A.; Yi, Grace T.; Haloua, Athena; Imka, Emily C.; Mitchell, Gianna G.; Asmar, Olivia C.; Leneghan, Halle A.; Sechkar, Edward A.

2016-01-01

Polymers and other oxidizable materials on the exterior of spacecraft in the low Earth orbit (LEO) space environment can be eroded due to reaction with atomic oxygen (AO). Therefore, in order to design durable spacecraft it is important to know the LEO AO erosion yield (E(sub y), volume loss per incident oxygen atom) of materials susceptible to AO reaction. Two spaceflight experiments, the Polymers Experiment and the Zenith Polymers Experiment, were developed to determine the AO E(sub y) of various polymers flown in ram, wake or zenith orientations in LEO. These experiments were flown as part of the Materials International Space Station Experiment 7 (MISSE 7) mission for 1.5 years on the exterior of the International Space Station (ISS). The experiments included Kapton H(TradeMark) witness samples for AO fluence determination in ram and zenith orientations. The Polymers Experiment also included samples to determine whether AO erosion of high and low ash containing polymers is dependent on fluence. This paper provides an overview of the MISSE 7 mission, a description of the flight experiments with details on the polymers flown, the characterization techniques used, the AO fluence for each exposure orientation, and the LEO E(sub y) results. The E(sub y) values ranged from 7.99x10(exp -28)cu cm/atom for TiO2/Al2O3 coated Teflon(TradeMark) fluorinated ethylene propylene (FEP) flown in the ram orientation to 1.22x10(exp -23cu cm/atom for polyvinyl alcohol (PVOH) flown in the zenith orientation. The E(sub y) of similar samples flown in different orientations has been compared to help determine solar exposure and associated heating effects on AO erosion. The E(sub y) data from these ISS spaceflight experiments provides valuable information for LEO spacecraft design purposes.

Field-structured material media and methods for synthesis thereof

DOEpatents

Martin, James E.; Hughes, Robert C.; Anderson, Robert A.

2001-09-18

The present application is directed to a new class of composite materials, called field-structured composite (FSC) materials, which comprise a oriented aggregate structure made of magnetic particles suspended in a nonmagnetic medium, and to a new class of processes for their manufacture. FSC materials have much potential for application, including use in chemical, optical, environmental, and mechanical sensors.

Surface and pseudo surface acoustic waves in langatate: predictions and measurements.

PubMed

Pereira da Cunha, Maurício; Malocha, Donald C; Adler, Eric L; Casey, Kevin J

2002-09-01

Langatate (LGT, La3Ga(5.5)Ta(0.5)O14) is a recent addition to materials of the trigonal crystal class 32, which is the same crystal class as quartz, langasite, langanite, and gallium phosphate. Langatate has several attractive acoustical properties, in particular: a measured bulk acoustic wave (BAW) resonator quality factor frequency product (Qf) of 16 million, comparable to that of AT cut quartz; high-piezoelectric coupling orientations, up to 0.5% for surface acoustic waves (SAWs), about five times larger than that of ST-X quartz; low power flow angle orientations in the vicinity of high coupling orientations; phase velocities about 20% smaller than those of ST-X quartz, facilitating the production of smaller, lower frequency devices; the existence of pseudo SAW modes for higher frequency applications. In this paper SAW contour plots of the phase velocity (vp), the electromechanical coupling coefficient (K2), the temperature coefficient of delay (TCD), and the power flow angle (PFA), are given showing the orientations in space in which high coupling is obtained, with the corresponding TCD, PFA, and vp characteristics for these orientations. This work reports experimental results on the SAW temperature fractional frequency variation (delta f/fo) and the TCD for several LGT orientations on the plane with Euler angles: (0 degrees, 132 degrees, psi). The temperature behavior has been measured directly on SAW wafers from 10 to 200 degrees C, and the results are compared with numerical predictions using our recently measured temperature coefficients for LGT material constants. This research also has uncovered temperature compensated orientations, which we have experimentally verified with parabolic behavior, turnover temperatures in the 130 to 160 degrees C range, and delta f/fo within 1000 ppm variation from 10 to 260 degrees C, appropriate for higher temperature device applications. Regarding the pseudo surface acoustic waves (PSAWs), results of calculations are presented for both the PSAW and the high velocity PSAW (HVPSAW) for some selected, rotated cuts. This study shows that propagation losses for the PSAWs of about 0.01 dB/wavelength, and phase velocities approximately 20% higher than that of the SAW, exist along specific orientations for the PSAW, thus showing the potential for somewhat higher frequency SAW device applications on this material, if required.

Utilization of Additive Manufacturing in Evaluating the Performance of Internally Defected Materials

NASA Astrophysics Data System (ADS)

Mourad, A.-H. I.; Ghazal, A. M.; Syam, M. M.; Qadi, O. D. Al; Jassmi, H. Al

2018-05-01

The elimination of internal defects in a material present in the raw material or generated during the manufacturing or service is difficult. The inclusions of the defects have an adverse effect on the load bearing capacity. The presence of the cracks subjected to a specific orientation in materials or machinery can cause devastating unexpected failure during operation. Analysis of the failure in the components with cracks is more confined to analytical and numerical evaluation. The experimental evaluation has been tedious due to the complexity of replicating the actual defected component. The potential of additive manufacturing in developing user-defined components with cracks for the experimental evaluation is explored in this research. The present research investigated the effect of the internal elliptical cracks aligned at different orientations on the mechanical performance of polylactic acid (Green filament). The Fusion Deposition Method was utilized for the development of the standard tensile specimens with internal elliptical crack oriented at 0°, 45° and 90° using UltiMaker 2. The results proved that there is a considerable reduction in the load bearing capacity due to the presence of the cracks. The maximum load bearing capacity decreased by 15.01% for the specimen with crack inclined at 0° to the lateral axis compared to crack- free specimen. The nature of the fracture and the stress-strain graph evidently showcase the brittle nature of the material. The SEM image of the fractured region proved the phenomenal characteristics such as strong adhesion between the layers and the proper material flow. In the light of the results of this work, it can be concluded that the 3-D printing methodology is effective for evaluating the mechanical performance of the internally defected material.

A cylindrical shell with an arbitrarily oriented crack

NASA Technical Reports Server (NTRS)

Yahsi, O. S.; Erdogan, F.

1982-01-01

The general problem of a shallow shell with constant curvatures is considered. It is assumed that the shell contains an arbitrarily oriented through crack and the material is specially orthotropic. The nonsymmetric problem is solved for arbitrary self equilibrating crack surface tractions, which, added to an appropriate solution for an uncracked shell, would give the result for a cracked shell under most general loading conditions. The problem is reduced to a system of five singular integral equations in a set of unknown functions representing relative displacements and rotations on the crack surfaces. The stress state around the crack tip is asymptotically analyzed and it is shown that the results are identical to those obtained from the two dimensional in plane and antiplane elasticity solutions. The numerical results are given for a cylindrical shell containing an arbitrarily oriented through crack. Some sample results showing the effect of the Poisson's ratio and the material orthotropy are also presented.

Muscle Fiber Orientation Angle Dependence of the Tensile Fracture Behavior of Frozen Fish Muscle

NASA Astrophysics Data System (ADS)

Hagura, Yoshio; Okamoto, Kiyoshi; Suzuki, Kanichi; Kubota, Kiyoshi

We have proposed a new cutting method for frozen fish named "cryo-cutting". This method applied tensile fracture force or bending fracture force to the frozen fish at appropriate low temperatures. In this paper, to clarify cryo-cutting mechanism, we analyzed tensile fracture behavior of the frozen fish muscle. In the analysis, the frozen fish muscle was considered unidirectionally fiber-reinforced composite material which consisted of fiber (muscle fiber) and matrix (connective tissue). Fracture criteria (maximum stress criterion, Tsai-Hill criterion) for the unidirectionally fiber-reinforced composite material were used. The following results were obtained: (1) By using Tsai-Hill criterion, muscle fiber orientation angle dependence of the tensile fracture stress could be calculated. (2) By using the maximum stress theory jointly with Tsai-Hill criterion, muscle fiber orientation angle dependence of the fracture mode of the frozen fish muscle could be estimated.

CRACK GROWTH RESPONSE OF ALLOY 690 IN SIMULATED PWR PRIMARY WATER

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

Toloczko, Mychailo B.; Bruemmer, Stephen M.

2009-12-01

The stress corrosion crack growth response of three extruded alloy 690 CRDM tube heats was investigated in several thermomechanical conditions. Extremely low propagation rates (< 1 x 10{sup -9} mm/s) were observed under constant stress intensity factor (K) loading at 325-350 C in the as-received, thermally treated (TT) materials despite using a variety of transitioning techniques. Post-test observation of the crack-growth surfaces revealed only isolated intergranular (IG) cracking. One-dimensional cold rolling to 17% reduction and testing in the S-L orientation did not promote enhanced stress corrosion rates. However, somewhat higher propagation rates were observed in a 30% cold-rolled alloy 690TTmore » specimen tested in the T-L orientation. Cracking of the cold-rolled material was promoted on grain boundaries oriented parallel to the rolling plane with the % IG increasing with the amount of cold rolling.« less

Self-shaping composites with programmable bioinspired microstructures

NASA Astrophysics Data System (ADS)

Erb, Randall M.; Sander, Jonathan S.; Grisch, Roman; Studart, André R.

2013-04-01

Shape change is a prevalent function apparent in a diverse set of natural structures, including seed dispersal units, climbing plants and carnivorous plants. Many of these natural materials change shape by using cellulose microfibrils at specific orientations to anisotropically restrict the swelling/shrinkage of their organic matrices upon external stimuli. This is in contrast to the material-specific mechanisms found in synthetic shape-memory systems. Here we propose a robust and universal method to replicate this unusual shape-changing mechanism of natural systems in artificial bioinspired composites. The technique is based upon the remote control of the orientation of reinforcing inorganic particles within the composite using a weak external magnetic field. Combining this reinforcement orientational control with swellable/shrinkable polymer matrices enables the creation of composites whose shape change can be programmed into the material’s microstructure rather than externally imposed. Such bioinspired approach can generate composites with unusual reversibility, twisting effects and site-specific programmable shape changes.

Process for ion-assisted laser deposition of biaxially textured layer on substrate

DOEpatents

Russo, R.E.; Reade, R.P.; Garrison, S.M.; Berdahl, P.

1995-07-11

A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film. 8 figs.

Process for ion-assisted laser deposition of biaxially textured layer on substrate

DOEpatents

Russo, Richard E.; Reade, Ronald P.; Garrison, Stephen M.; Berdahl, Paul

1995-01-01

A process for depositing a biaxially aligned intermediate layer over a non-single crystal substrate is disclosed which permits the subsequent deposition thereon of a biaxially oriented superconducting film. The process comprises depositing on a substrate by laser ablation a material capable of being biaxially oriented and also capable of inhibiting the migration of substrate materials through the intermediate layer into such a superconducting film, while simultaneously bombarding the substrate with an ion beam. In a preferred embodiment, the deposition is carried out in the same chamber used to subsequently deposit a superconducting film over the intermediate layer. In a further aspect of the invention, the deposition of the superconducting layer over the biaxially oriented intermediate layer is also carried out by laser ablation with optional additional bombardment of the coated substrate with an ion beam during the deposition of the superconducting film.

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

Zeng, Fan W.; Contescu, Cristian I.; Gallego, Nidia C.

Laser ultrasonic line source methods have been used to study elastic anisotropy in nuclear graphites by measuring shear wave birefringence. Depending on the manufacturing processes used during production, nuclear graphites can exhibit various degrees of material anisotropy related to preferred crystallite orientation and to microcracking. In this paper, laser ultrasonic line source measurements of shear wave birefringence on NBG-25 have been performed to assess elastic anisotropy. Laser line sources allow specific polarizations for shear waves to be transmitted – the corresponding wavespeeds can be used to compute bulk, elastic moduli that serve to quantify anisotropy. These modulus values can bemore » interpreted using physical property models based on orientation distribution coefficients and microcrack-modified, single crystal moduli to represent the combined effects of crystallite orientation and microcracking on material anisotropy. Finally, ultrasonic results are compared to and contrasted with measurements of anisotropy based on the coefficient of thermal expansion to show the relationship of results from these techniques.« less

Orientation of Zn3P2 films via phosphidation of Zn precursors

NASA Astrophysics Data System (ADS)

Katsube, Ryoji; Nose, Yoshitaro

2017-02-01

Orientation of solar absorber is an important factor to achieve high efficiency of thin film solar cells. In the case of Zn3P2 which is a promising absorber of low-cost and high-efficiency solar cells, (110)/(001) orientation was only reported in previous studies. We have successfully prepared (101)-oriented Zn3P2 films by phosphidation of (0001)-oriented Zn films at 350 °C. The phosphidation mechanism of Zn is discussed through STEM observations on the partially-reacted sample and the consideration of the relationship between the crystal structures of Zn and Zn3P2 . We revealed that (0001)-oriented Zn led to nucleation of (101)-oriented Zn3P2 due to the similarity in atomic arrangement between Zn and Zn3P2 . The electrical resistivity of the (101)-oriented Zn3P2 film was lower than those of (110)/(001)-oriented films, which is an advantage of the phosphidation technique to the growth processes in previous works. The results in this study demonstrated that well-conductive Zn3P2 films could be obtained by controlling orientations of crystal grains, and provide a guiding principle for microstructure control in absorber materials.

Evolution of Deformation and Recrystallization Textures in High-Purity Ni and the Ni-5 at. pct W Alloy

NASA Astrophysics Data System (ADS)

Bhattacharjee, Pinaki P.; Ray, Ranjit K.; Tsuji, Nobuhiro

2010-11-01

An attempt has been made to study the evolution of texture in high-purity Ni and Ni-5 at. pct W alloy prepared by the powder metallurgy route followed by heavy cold rolling ( 95 pct deformation) and recrystallization. The deformation textures of the two materials are of typical pure metal or Cu-type texture. Cube-oriented ( left\\{ {00 1} right\\}left< { 100} rightrangle ) regions are present in the deformed state as long thin bands, elongated in the rolling direction (RD). These bands are characterized by a high orientation gradient inside, which is a result of the rotation of the cube-oriented cells around the RD toward the RD-rotated cube ( left\\{ {0 1 3} right\\}left< { 100} rightrangle ). Low-temperature annealing produces a weak cube texture along with the left\\{ {0 1 3} right\\}left< { 100} rightrangle component, with the latter being much stronger in high-purity Ni than in the Ni-W alloy. At higher temperatures, the cube texture is strengthened considerably in the Ni-W alloy; however, the cube volume fraction in high-purity Ni is significantly lower because of the retention of the left\\{ {0 1 3} right\\}left< { 100} rightrangle component. The difference in the relative strengths of the cube, and the left\\{ {0 1 3} right\\}left< { 100} rightrangle components in the two materials is evident from the beginning of recrystallization in which more left\\{ {0 1 3} right\\}left< { 100} rightrangle -oriented grains than near cube grains form in high-purity Ni. The preferential nucleation of the near cube and the left\\{ {0 1 3} right\\}left< { 100} rightrangle grains in these materials seems to be a result of the high orientation gradients associated with the cube bands that offer a favorable environment for early nucleation.

Assessment of langatate material constants and temperature coefficients using SAW delay line measurements.

PubMed

Sturtevant, Blake T; Pereira da Cunha, Mauricio

2010-03-01

This paper reports on the assessment of langatate (LGT) acoustic material constants and temperature coefficients by surface acoustic wave (SAW) delay line measurements up to 130 degrees C. Based upon a full set of material constants recently reported by the authors, 7 orientations in the LGT plane with Euler angles (90 degrees, 23 degrees, Psi) were identified for testing. Each of the 7 selected orientations exhibited calculated coupling coefficients (K(2)) between 0.2% and 0.75% and also showed a large range of predicted temperature coefficient of delay (TCD) values around room temperature. Additionally, methods for estimating the uncertainty in predicted SAW propagation properties were developed and applied to SAW phase velocity and temperature coefficient of delay calculations. Starting from a purchased LGT boule, the SAW wafers used in this work were aligned, cut, ground, and polished at University of Maine facilities, followed by device fabrication and testing. Using repeated measurements of 2 devices on separate wafers for each of the 7 orientations, the room temperature SAW phase velocities were extracted with a precision of 0.1% and found to be in agreement with the predicted values. The normalized frequency change and the temperature coefficient of delay for all 7 orientations agreed with predictions within the uncertainty of the measurement and the predictions over the entire 120 degrees C temperature range measured. Two orientations, with Euler angles (90 degrees, 23 degrees, 123 degrees) and (90 degrees, 23 degrees, 119 degrees), were found to have high predicted coupling for LGT (K(2) > 0.5%) and were shown experimentally to exhibit temperature compensation in the vicinity of room temperature, with turnover temperatures at 50 and 60 degrees C, respectively.

Effects of Aeroelastic Tailoring on Anisotropic Composite Material Beam Models of Helicopter Blades

DTIC Science & Technology

1989-05-01

34 means that a layer of material at some distance above a structural midsurface reference location has the identical ply thickness, angular orientation...and material properties as that of a lamina at an identical distance below the midsurface [1]. If the fibers are placed off-axis in the upper and

Creating Printed Materials for Mathematics with a Macintosh Computer.

ERIC Educational Resources Information Center

Mahler, Philip

This document gives instructions on how to use a Macintosh computer to create printed materials for mathematics. A Macintosh computer, Microsoft Word, and objected-oriented (Draw-type) art program, and a function-graphing program are capable of producing high quality printed instructional materials for mathematics. Word 5.1 has an equation editor…

Multimedia material about velopharynx and primary palatoplasty for orientation of caregivers of children with cleft lip and palate.

PubMed

Costa, Tarcila Lima da; Souza, Olivia Mesquita Vieira de; Carneiro, Homero Aferri; Chiquito Netto, Cristianne; Pegoraro-Krook, Maria Inês; Dutka, Jeniffer de Cássia Rillo

2016-01-01

The objective of this study was to describe the process of elaboration and evaluation of multimedia material for caregivers about velopharynx, speech, and primary palatoplasty in babies with cleft lip and palate. The elaboration of the material involved an interdisciplinary relationship between the fields of Speech Language Pathology and Audiology, Dentistry and Arts. The definition and execution of the following activities were based on the principles of art education involving the following: characterization of audience, characterization of content, identification and elaboration of illustrations, characterization of educational approach, elaboration of text and narratives, definition of audiovisual sequence, and video preparation. The material was evaluated with the participation of 41 caregivers of patients with cleft lip and palate involving the comparison between acquired knowledge using an evaluation script applied before and after presenting the material. An increase was observed in correct responses regarding the role of velopharynx and the importance of primary palatoplasty for speech. The multimedia was effective in optimizing the knowledge of caregivers, suggesting the importance of such material during orientation.

Ferro- and piezoelectric properties of polar-axis-oriented CaBi4Ti4O15 films

NASA Astrophysics Data System (ADS)

Kato, Kazumi; Fu, Desheng; Suzuki, Kazuyuki; Tanaka, Kiyotaka; Nishizawa, Kaori; Miki, Takeshi

2004-05-01

Polar-axis-oriented CaBi4Ti4O15 (CBTi144) films were fabricated on Pt foils using a complex metal alkoxide solution. The 500-nm-thick film showed the columnar structure and consisted of well-developed grains. The a/b-axis orientation of the ferroelectric films is considered to be associated with the preferred orientation of Pt foil. The film showed good ferro- and piezoelectric properties. The Pr and Ec were 25 μC/cm2 and 306 kV/cm, respectively, at an applied voltage of 115 V. The d33 was characterized as 30 pm/V by piezoresponse force microscopy. The values were twice as large as those of the CBTi144 thin film with random orientation. The polar-axis-oriented CBTi144 films would open up possibilities for devices as Pb-free piezoelectric materials.

Simulation of Orientation in Injection Molding of High Aspect Ratio Particle Thermoplastic Composites

NASA Astrophysics Data System (ADS)

Vélez-García, Gregorio M.; Ortman, Kevin C.; Eberle, Aaron P. R.; Wapperom, Peter; Baird, Donald G.

2008-07-01

A 2D coupled Hele-Shaw flow approximation for predicting the flow-induced orientation of high aspect ratio particles in injection molded composite parts is presented. For a highly concentrated short glass fiber PBT suspension, the impact of inter-particle interactions and the orientation at the gate is investigated for a center-gated disk using material parameters determined from rheometry. Experimental orientation is determined from confocal laser micrographs using the methods of ellipses. The constitutive equations are discretized using discontinuous Galerkin Finite Elements. Model predictions are significantly improved by using a localized orientation measured experimentally at the gate region instead of random or averaged gapwise measured orientation assumed in previous studies. The predicted profile in different radial positions can be related to the layered structure along the gapwise direction. Model modifications including interactions have lower impact than the initial conditions.

Anisotropic mechanical behavior of an injection molded short fiber reinforced thermoplastic

NASA Astrophysics Data System (ADS)

Lopez, Delphine; Thuillier, Sandrine; Bessières, Nicolas; Grohens, Yves

2016-10-01

A short fiber reinforced thermoplastic was injected into a rectangular mold, in order to prepare samples to characterize the mechanical behavior of the material. The injection process was simulated with Moldflow and a cutting pattern was deduced from the predicted fiber orientation, leading to samples with several well-defined orientations with respect to the injection direction. Monotonic tensile tests up to rupture, as well as complex cycles made of loading steps followed by relaxation steps at different strain levels were performed, in order to check the reproducibility for a given orientation. Moreover, the fiber orientation in the central part of the tensile samples was also analyzed with X-ray tomography. The results show that the mechanical behavior for each orientation (among 6) was rather reproducible, thus validating the cutting pattern.

An in silico framework to analyze the anisotropic shear wave mechanics in cardiac shear wave elastography

NASA Astrophysics Data System (ADS)

Caenen, Annette; Pernot, Mathieu; Peirlinck, Mathias; Mertens, Luc; Swillens, Abigail; Segers, Patrick

2018-04-01

Shear wave elastography (SWE) is a potential tool to non-invasively assess cardiac muscle stiffness. This study focused on the effect of the orthotropic material properties and mechanical loading on the performance of cardiac SWE, as it is known that these factors contribute to complex 3D anisotropic shear wave propagation. To investigate the specific impact of these complexities, we constructed a finite element model with an orthotropic material law subjected to different uniaxial stretches to simulate SWE in the stressed cardiac wall. Group and phase speed were analyzed in function of tissue thickness and virtual probe rotation angle. Tissue stretching increased the group and phase speed of the simulated shear wave, especially in the direction of the muscle fiber. As the model provided access to the true fiber orientation and material properties, we assessed the accuracy of two fiber orientation extraction methods based on SWE. We found a higher accuracy (but lower robustness) when extracting fiber orientations based on the location of maximal shear wave speed instead of the angle of the major axis of the ellipsoidal group speed surface. Both methods had a comparable performance for the center region of the cardiac wall, and performed less well towards the edges. Lastly, we also assessed the (theoretical) impact of pathology on shear wave physics and characterization in the model. It was found that SWE was able to detect changes in fiber orientation and material characteristics, potentially associated with cardiac pathologies such as myocardial fibrosis. Furthermore, the model showed clearly altered shear wave patterns for the fibrotic myocardium compared to the healthy myocardium, which forms an initial but promising outcome of this modeling study.

Evolution of plastic anisotropy for high-strain-rate computations

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

Schiferl, S.K.; Maudlin, P.J.

1994-12-01

A model for anisotropic material strength, and for changes in the anisotropy due to plastic strain, is described. This model has been developed for use in high-rate, explicit, Lagrangian multidimensional continuum-mechanics codes. The model handles anisotropies in single-phase materials, in particular the anisotropies due to crystallographic texture--preferred orientations of the single-crystal grains. Textural anisotropies, and the changes in these anisotropies, depend overwhelmingly no the crystal structure of the material and on the deformation history. The changes, particularly for a complex deformations, are not amenable to simple analytical forms. To handle this problem, the material model described here includes a texturemore » code, or micromechanical calculation, coupled to a continuum code. The texture code updates grain orientations as a function of tensor plastic strain, and calculates the yield strength in different directions. A yield function is fitted to these yield points. For each computational cell in the continuum simulation, the texture code tracks a particular set of grain orientations. The orientations will change due to the tensor strain history, and the yield function will change accordingly. Hence, the continuum code supplies a tensor strain to the texture code, and the texture code supplies an updated yield function to the continuum code. Since significant texture changes require relatively large strains--typically, a few percent or more--the texture code is not called very often, and the increase in computer time is not excessive. The model was implemented, using a finite-element continuum code and a texture code specialized for hexagonal-close-packed crystal structures. The results for several uniaxial stress problems and an explosive-forming problem are shown.« less

Modulation of the electrophysiological correlates of retrieval cue processing by the specificity of task demands.

PubMed

Johnson, Jeffrey D; Rugg, Michael D

2006-02-03

Retrieval orientation refers to the differential processing of retrieval cues according to the type of information sought from memory (e.g., words vs. pictures). In the present study, event-related potentials (ERPs) were employed to investigate whether the neural correlates of differential retrieval orientations are sensitive to the specificity of the retrieval demands of the test task. In separate study-test phases, subjects encoded lists of intermixed words and pictures, and then undertook one of two retrieval tests, in both of which the retrieval cues were exclusively words. In the recognition test, subjects performed 'old/new' discriminations on the test items, and old items corresponded to only one class of studied material (words or pictures). In the exclusion test, old items corresponded to both classes of study material, and subjects were required to respond 'old' only to test items corresponding to a designated class of material. Thus, demands for retrieval specificity were greater in the exclusion test than during recognition. ERPs elicited by correctly classified new items in the two types of test were contrasted according to whether words or pictures were the sought-for material. Material-dependent ERP effects were evident in both tests, but the effects onset earlier and offset later in the exclusion test. The findings suggest that differential processing of retrieval cues, and hence the adoption of differential retrieval orientations, varies according to the specificity of the retrieval goal.

Standard Chinese: A Modular Approach. Student Workbook. Module 1: Orientation; Module 2: Biographic Information.

ERIC Educational Resources Information Center

Defense Language Inst., Monterey, CA.

Texts in spoken Standard Chinese were developed to improve and update Chinese materials to reflect current usage in Beijing and Taipei. The focus is on communicating in Chinese in practical situations. The overall course is organized into 10 modules, student workbooks, and resource modules. This workbook covers the orientation and biographic…

Zielstrebiger Einsatz von Unterrichtsmitteln und Ausbau des Fachunterrichtsraumsystems (Goal-oriented Introduction of Teaching Aids and Development of Physical Area for Language Teaching)

ERIC Educational Resources Information Center

Hoffmann, Werner

1974-01-01

Contains remarks concerning lesson orientation in the use of the obligatory instructional aids and of reserves of teaching materials, also in relation to minimal requirements in the development of the physical teaching area for foreign language instruction. (Text is in German.) (IFS/WGA)

Learning to Learn a Foreign Language. Principles of Second Language Acquisition: An Orientation for Foreign Language Teachers.

ERIC Educational Resources Information Center

Pfannkuche, Anthony; And Others

The manual designed to accompany an orientation seminar for students concerning language learning processes and strategies and the design of their program includes materials for five sessions, in three sections. The first section covers language learning and acquisition in general and contains a survey of the participants' foreign language…

Calculus: A Computer Oriented Presentation, Part 1 [and] Part 2.

ERIC Educational Resources Information Center

Stenberg, Warren; Walker, Robert J.

Parts one and two of a one-year computer-oriented calculus course (without analytic geometry) are presented. The ideas of calculus are introduced and motivated through computer (i.e., algorithmic) concepts. An introduction to computing via algorithms and a simple flow chart language allows the book to be self-contained, except that material on…

Material for "Substrate temperature controls molecular orientation in two-component vapor- deposited glasses." Soft Matter, 2016, 12, 3265.

DOE Data Explorer

Jiang, Jing [Nanjing University; Walters, Diane M [University of Wisconsin-Madison; Zhou, Dongshan [Nanjing University; Ediger, Mark D [University of Wisconsin-Madison

2016-08-18

Data set for work presented in Jiang, J.; Walters, D. M.; Zhou, D.; Ediger, M. D. “Substrate Temperature Controls Molecular Orientation in Two -Component Vapor-deposited Glasses.” Soft Matt. 2016, 12, 3265. Includes all data presented in the manuscript as well as example raw data and analysis.

Instructional Experiment of Practical Competencies-Oriented Teaching Materials in Technical Universities

ERIC Educational Resources Information Center

Chen, Su-Chang

2010-01-01

This study aims to conduct experimental instruction on the human resource management unit of business management in practical competencies-oriented business program developed by Chen (2005). This study is based on the quasi-experiment method and the subjects are two classes of students in a four-year technical university who have completed the…

Extraction of volatile and metals from extraterrestrial materials

NASA Technical Reports Server (NTRS)

Lewis, John S.

1990-01-01

Since March 1, 1989, attention was concentrated on the extraction of ilmenite from extraterrestrial materials and on the planning and development of laboratory facilities for carbonyl extraction of ferrous metal alloys. Work under three subcontracts was administered by this project: (1) electrolytic production of oxygen from molten lunar materials; (2) microwave processing of lunar materials; and (3) production of a resource-oriented space science data base.

Influence of Fiber Orientation on Single-Point Cutting Fracture Behavior of Carbon-Fiber/Epoxy Prepreg Sheets.

PubMed

Wei, Yingying; An, Qinglong; Cai, Xiaojiang; Chen, Ming; Ming, Weiwei

2015-10-02

The purpose of this article is to investigate the influences of carbon fibers on the fracture mechanism of carbon fibers both in macroscopic view and microscopic view by using single-point flying cutting method. Cutting tools with three different materials were used in this research, namely, PCD (polycrystalline diamond) tool, CVD (chemical vapor deposition) diamond thin film coated carbide tool and uncoated carbide tool. The influence of fiber orientation on the cutting force and fracture topography were analyzed and conclusions were drawn that cutting forces are not affected by cutting speeds but significantly influenced by the fiber orientation. Cutting forces presented smaller values in the fiber orientation of 0/180° and 15/165° but the highest one in 30/150°. The fracture mechanism of carbon fibers was studied in different cutting conditions such as 0° orientation angle, 90° orientation angle, orientation angles along fiber direction, and orientation angles inverse to the fiber direction. In addition, a prediction model on the cutting defects of carbon fiber reinforced plastic was established based on acoustic emission (AE) signals.

Influence of Fiber Orientation on Single-Point Cutting Fracture Behavior of Carbon-Fiber/Epoxy Prepreg Sheets

PubMed Central

Wei, Yingying; An, Qinglong; Cai, Xiaojiang; Chen, Ming; Ming, Weiwei

2015-01-01

The purpose of this article is to investigate the influences of carbon fibers on the fracture mechanism of carbon fibers both in macroscopic view and microscopic view by using single-point flying cutting method. Cutting tools with three different materials were used in this research, namely, PCD (polycrystalline diamond) tool, CVD (chemical vapor deposition) diamond thin film coated carbide tool and uncoated carbide tool. The influence of fiber orientation on the cutting force and fracture topography were analyzed and conclusions were drawn that cutting forces are not affected by cutting speeds but significantly influenced by the fiber orientation. Cutting forces presented smaller values in the fiber orientation of 0/180° and 15/165° but the highest one in 30/150°. The fracture mechanism of carbon fibers was studied in different cutting conditions such as 0° orientation angle, 90° orientation angle, orientation angles along fiber direction, and orientation angles inverse to the fiber direction. In addition, a prediction model on the cutting defects of carbon fiber reinforced plastic was established based on acoustic emission (AE) signals. PMID:28793597

Oriented MOF-polymer Composite Nanofiber Membranes for High Proton Conductivity at High Temperature and Anhydrous Condition

PubMed Central

Wu, Bin; Pan, Jiefeng; Ge, Liang; Wu, Liang; Wang, Huanting; Xu, Tongwen

2014-01-01

The novel oriented electrospun nanofiber membrane composed of MOFs and SPPESK has been synthesized for proton exchange membrane fuel cell operating at high temperature and anhydrous conditions. It is clear that the oriented nanofiber membrane displays the higher proton conductivity than that of the disordered nanofiber membrane or the membrane prepared by conventional solvent-casting method (without nanofibers). Nanofibers within the membranes are significantly oriented. The proton conductivity of the oriented nanofiber membrane can reach up to (8.2 ± 0.16) × 10−2 S cm−1 at 160°C under anhydrous condition for the highly orientation of nanofibers. Moreover, the oxidative stability and resistance of methanol permeability of the nanofibers membrane are obviously improved with an increase in orientation of nanofibers. The observed methanol permeability of 0.707 × 10−7 cm2 s−1 is about 6% of Nafion-115. Consequently, orientated nanofibers membrane is proved to be a promising material as the proton exchange membrane for potential application in direct methanol fuel cells. PMID:25082522

CaTiO.sub.3 Interfacial template structure on semiconductor-based material and the growth of electroceramic thin-films in the perovskite class

DOEpatents

McKee, Rodney Allen; Walker, Frederick Joseph

1998-01-01

A structure including a film of a desired perovskite oxide which overlies and is fully commensurate with the material surface of a semiconductor-based substrate and an associated process for constructing the structure involves the build up of an interfacial template film of perovskite between the material surface and the desired perovskite film. The lattice parameters of the material surface and the perovskite of the template film are taken into account so that during the growth of the perovskite template film upon the material surface, the orientation of the perovskite of the template is rotated 45.degree. with respect to the orientation of the underlying material surface and thereby effects a transition in the lattice structure from fcc (of the semiconductor-based material) to the simple cubic lattice structure of perovskite while the fully commensurate periodicity between the perovskite template film and the underlying material surface is maintained. The film-growth techniques of the invention can be used to fabricate solid state electrical components wherein a perovskite film is built up upon a semiconductor-based material and the perovskite film is adapted to exhibit ferroelectric, piezoelectric, pyroelectric, electro-optic or large dielectric properties during use of the component.

Application of Single Crystal Failure Criteria: Theory and Turbine Blade Case Study

NASA Technical Reports Server (NTRS)

Sayyah, Tarek; Swanson, Gregory R.; Schonberg, W. P.

1999-01-01

The orientation of the single crystal material within a structural component is known to affect the strength and life of the part. The first stage blade of the High Pressure Fuel Turbopump (HPFTP)/ Alternative Turbopump Development (ATD), of the Space Shuttle Main Engine (SSME) was used to study the effects of secondary axis'orientation angles on the failure rate of the blade. A new failure criterion was developed based on normal and shear strains on the primary crystallographic planes. The criterion was verified using low cycle fatigue (LCF) specimen data and a finite element model of the test specimens. The criterion was then used to study ATD/HPFTP first stage blade failure events. A detailed ANSYS finite element model of the blade was used to calculate the failure parameter for the different crystallographic orientations. A total of 297 cases were run to cover a wide range of acceptable orientations within the blade. Those orientations are related to the base crystallographic coordinate system that was created in the ANSYS finite element model. Contour plots of the criterion as a function of orientation for the blade tip and attachment were obtained. Results of the analysis revealed a 40% increase in the failure parameter due to changing of the primary and secondary axes of material orientations. A comparison between failure criterion predictions and actual engine test data was then conducted. The engine test data comes from two ATD/HPFTP builds (units F3- 4B and F6-5D), which were ground tested on the SSME at the Stennis Space Center in Mississippi. Both units experienced cracking of the airfoil tips in multiple blades, but only a few cracks grew all the way across the wall of the hollow core airfoil.

Experimental study of grain interactions on rolling texture development in face-centered cubic metals

NASA Astrophysics Data System (ADS)

Kumar Ray, Atish

There exists considerable debate in the texture community about whether grain interactions are a necessary factor to explain the development of deformation textures in polycrystalline metals. Computer simulations indicate that grain interactions play a significant role, while experimental evidence shows that the material type and starting orientation are more important in the development of texture and microstructure. A balanced review of the literature on face-centered cubic metals shows that the opposing viewpoints have developed due to the lack of any complete experimental study which considers both the intrinsic (material type and starting orientation) and extrinsic (grain interaction) factors. In this study, a novel method was developed to assemble ideally orientated crystalline aggregates in 99.99% aluminum (Al) or copper (Cu) to experimentally evaluate the effect of grain interactions on room temperature deformation texture. Ideal orientations relevant to face-centered cubic rolling textures, Cube {100} <001>, Goss {110} <001>, Brass {110} <11¯2> and Copper {112} <111¯> were paired in different combinations and deformed by plane strain compression to moderate strain levels of 1.0 to 1.5. Orientation dependent mechanical behavior was distinguishable from that of the neighbor-influenced behavior. In interacting crystals the constraint on the rolling direction shear strains (gammaXY , gammaXZ) was found to be most critical to show the effect of interactions via the evolution of local microstructure and microtexture. Interacting crystals with increasing deformations were observed to gradually rotate towards the S-component, {123} <634>. Apart from the average lattice reorientations, the interacting crystals also developed strong long-range orientation gradients inside the bulk of the crystal, which were identified as accumulating misorientations across the deformation boundaries. Based on a statistical procedure using quaternions, the orientation and interaction related heterogeneous deformations were characterized by three principal component vectors and their respective eigenvalues for both the orientation and misorientation distributions. For the case of a medium stacking fault energy metal like Cu, the texture and microstructure development depends wholly on the starting orientations. Microstructural instabilities in Cu are explained through a local slip clustering process, and the possible role of grain interactions on such instabilities is proposed. In contrast, the texture and microstructure development in a high stacking fault energy metal like Al is found to be dependent on the grain interactions. In general, orientation, grain interaction and material type were found to be key factors in the development of rolling textures in face-centered cubic metals and alloys. Moreso, in the texture development not any single parameter can be held responsible, rather, the interdependency of each of the three parameters must be considered. In this frame-work polycrystalline grains can be classified into four types according to their stability and susceptibility during deformation.

Job Corps Intergroup Relations Program.

ERIC Educational Resources Information Center

Job Corps (DOL), Washington, DC.

The Job Corps Intergroup Relations Program provides an integrated curriculum involving orientation, residential living, education, and vocational training. These instructional materials for the program provide guidelines and materials emphasizing ethnic contributions in order to improve human relations among ethnic groups and between women and…

Modal Analysis of Embedded Passive Damping Materials in Composite Plates with Different Orientations

NASA Technical Reports Server (NTRS)

Kehoe, Michael; Kolkailah, Faysal A.; Elghandour, Eltahry I.

1998-01-01

This report presents an experimental and numerical investigation of the free vibration of cantilevered composite plates with and without passive damping. A total of seven composite material plates are considered. The lay-up sequences for the two plates without damping are [90/90/0/0], and [90/0/90/0]; the other five plates are the same as the first two with two embedded layers of passive damping material. The passive damping material is embedded at different locations in the plate with orientation [90/0/90/0],. The damping material employed is a 3M material (SJ-2015 ISD 112) with peak damping properties in the ambient temperature range (32 F to 140 F). The composite material used is a carbon fiber (977-2)/epoxy resin (IM7). The effect of the passive damping system employed in this study for the composite plates are discussed. Modal testing is performed on these plates to determine resonant frequencies, amplitude and mode shape information. Numerical results are obtained using COSMOS/M software for the plates without damping. The experimental and numerical results are in very good agreement for different laminated plates without damping layers.

Adjoint-based optimization of mechanical performance in polycrystalline materials and structures through texture control

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

Gu, Grace; Brown, Judith Alice; Bishop, Joseph E.

The texture of a polycrystalline material refers to the preferred orientation of the grains within the material. In metallic materials, texture can significantly affect the mechanical properties such as elastic moduli, yield stress, strain hardening, and fracture toughness. Recent advances in additive manufacturing of metallic materials offer the possibility in the not too distant future of controlling the spatial variation of texture. In this work, we investigate the advantages, in terms of mechanical performance, of allowing the texture to vary spatially. We use an adjoint-based gradient optimization algorithm within a finite element solver (COMSOL) to optimize several engineering quantities ofmore » interest in a simple structure (hole in a plate) and loading (uniaxial tension) condition. As a first step to general texture optimization, we consider the idealized case of a pure fiber texture in which the homogenized properties are transversely isotropic. In this special case, the only spatially varying design variables are the three Euler angles that prescribe the orientation of the homogenized material at each point within the structure. This work paves a new way to design metallic materials for tunable mechanical properties at the microstructure level.« less

A Ballistic Material Model for Cross-Plied Unidirectional Ultra-High Molecular-Weight Polyethylene Fiber-Reinforced Armor-Grade Composites

DTIC Science & Technology

2008-01-01

strength polymeric fibers such as aramid (e.g. Kevlar ®, Twaron®, etc.) or oriented polyethy- lene fibers (e.g. Spectra®, Dyneema®, etc.) with an... phenolic -poly-vinyl-butyral resin and on 0◦/90◦ cross- plied oriented polyethylene fiber-reinforced vinyl-ester resin are widely used in hard personnel...are: (a) poly-aramids (e.g. Kevlar ®, Twaron®, Technora®); (b) highly oriented ultra-highmolecular-weight polyethylene, UHMWPE (e.g. Spectra®, Dyneema

Growth of <111>-oriented Cu layer on thin TaWN films

NASA Astrophysics Data System (ADS)

Takeyama, Mayumi B.; Sato, Masaru

2017-07-01

In this study, we examine the growth of a <111>-oriented Cu layer on a thin TaWN ternary alloy barrier for good electromigration reliability. The strongly preferentially oriented Cu(111) layer is observed on a thin TaWN barrier even in the as-deposited Cu (100 nm)/TaWN (5 nm)/Si system. Also, this system tolerates annealing at 700 °C for 1 h without silicide reaction. It is revealed that the TaWN film is one of the excellent barriers with thermal stability and low resistivity. Simultaneously, the TaWN film is a candidate for a superior underlying material to achieve the Cu(111) preferential orientation.

3D highly oriented nanoparticulate and microparticulate array ofmetal oxide materials

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

Vayssieres, Lionel; Guo, Jinghua; Nordgren, Joseph

2006-09-15

Advanced nano and micro particulate thin films of 3d transition and post-transition metal oxides consisting of nanorods and microrods with parallel and perpendicular orientation with respect to the substrate normal, have been successfully grown onto various substrates by heteronucleation, without template and/or surfactant, from the aqueous condensation of solution of metal salts or metal complexes (aqueous chemical growth). Three-dimensional arrays of iron oxide nanorods and zinc oxide nanorods with parallel and perpendicular orientation are presented as well as the oxygen K-edge polarization dependent x-ray absorption spectroscopy (XAS) study of anisotropic perpendicularly oriented microrod array of ZnO performed at synchrotron radiationmore » source facility.« less

The Plunge Phase of Friction Stir Welding

NASA Technical Reports Server (NTRS)

McClure, John C.

2005-01-01

The many advantages of Friction Stir Welding have led to a relatively rapid acceptance in the often conservative welding community. Because the process is so different from traditional fusion welding, with which most investigators are most familiar, there remain many aspects of FSW for which there is no clear consensus. For example, the well known onion rings seen in transverse sections have been variously interpreted as grain size variations, variation in density of second phase particles and parts of the carousel of material rotating with the pin that have been shed from the carousel. Using Orientation Imaging Microscopy, Schneider has recently noted that the onion rings have a different orientation (and hence etch differently) than the surrounding material, and this orientation is consistent with slip plane orientations at the edge of the carousel. Likewise, the forces and torque exerted by the FSW tool on the work piece largely remain unaccounted for. Although these forces are routinely measured by investigators with commercial instrumented welders, they are rarely reported or even qualitatively analyzed. This paper will introduce a model based on a carousel or disk of material that rotates with the tool to estimate the torque and plunge force required to plunge a tool into the work piece. A stationary tool is modeled rather than the moving tool because effects such as thermal transients and metallurgical changes in the sample (primarily aging in aluminum) can be more easily accounted for. It is believed, however, that with some modifications the model should be applicable to a moving tool also.

Outstanding compressive creep strength in Cr/Ir-codoped (Mo0.85Nb0.15)Si2 crystals with the unique cross-lamellar microstructure.

PubMed

Hagihara, Koji; Ikenishi, Takaaki; Araki, Haruka; Nakano, Takayoshi

2017-06-21

A (Mo 0.85 Nb 0.15 )Si 2 crystal with an oriented, lamellar, C40/C11 b two-phase microstructure is a promising ultrahigh-temperature (UHT) structural material, but its low room-temperature fracture toughness and low high-temperature strength prevent its practical application. As a possibility to overcome these problems, we first found a development of unique "cross-lamellar microstructure", by the cooping of Cr and Ir. The cross-lamellar microstructure consists of a rod-like C11 b -phase grains that extend along a direction perpendicular to the lamellar interface in addition to the C40/C11 b fine lamellae. In this study, the effectiveness of the cross-lamellar microstructure for improving the high-temperature creep deformation property, being the most essential for UHT materials, was examined by using the oriented crystals. The creep rate significantly reduced along a loading orientation parallel to the lamellar interface. Furthermore, the degradation in creep strength for other loading orientation that is not parallel to the lamellar interface, which has been a serious problem up to now, was also suppressed. The results demonstrated that the simultaneous improvement of high-temperature creep strength and room temperature fracture toughness can be first accomplished by the development of unique cross-lamellar microstructure, which opens a potential avenue for the development of novel UHT materials as alternatives to existing Ni-based superalloys.

Design considerations for a Space Shuttle Main Engine turbine blade made of single crystal material

NASA Technical Reports Server (NTRS)

Abdul-Aziz, A.; August, R.; Nagpal, V.

1993-01-01

Nonlinear finite-element structural analyses were performed on the first stage high-pressure fuel turbopump blade of the Space Shuttle Main Engine. The analyses examined the structural response and the dynamic characteristics at typical operating conditions. Single crystal material PWA-1480 was considered for the analyses. Structural response and the blade natural frequencies with respect to the crystal orientation were investigated. The analyses were conducted based on typical test stand engine cycle. Influence of combined thermal, aerodynamic, and centrifugal loadings was considered. Results obtained showed that the single crystal secondary orientation effects on the maximum principal stresses are not highly significant.

Live and Web-based orientations are comparable for a required rotation.

PubMed

Prunuske, Jacob

2010-03-01

Studies show equivalency in knowledge when measured following Web-based learning and live lecture. However, the effectiveness of a Web-based orientation for a required clinical rotation is unknown. Medical students viewed a Web-based orientation and completed a 13-item evaluation before beginning a required 6-week community medicine rotation. Evaluation data from 2007-2008 live orientation sessions were compared to responses from 2008-2009 Web-based orientation sessions. Data were analyzed by two-sample tests of proportion. A total of 169 students completed surveys during the study period--78 following the live and 91 following the Web-based orientation. Response rates were equal in the two groups. The survey tool had a high level of reliability (Cronbach's alpha=0.96). There was no statistical difference in student evaluations for 12 of 13 orientation evaluation items. Live and Web-based formats are comparable for presenting orientation materials to a required clinical rotation. Students felt the purpose of the rotation, educational goals, course structure, and requirements were clearly presented regardless of format. Transition from a live to Web-based format reduced faculty time required to present at rotation orientations.

Characterization of inhomogeneous and anisotropic steel welds by ultrasonic array measurements

NASA Astrophysics Data System (ADS)

Fan, Z.; Lowe, M. J. S.

2013-01-01

Austenitic welds are difficult to inspect non-destructively by ultrasound due to the anisotropic and inhomogeneous material in the weld, which causes spatial deviation of ultrasonic beams. A common way to describe such material is to consider it as transversely isotropic, in which the plane perpendicular to the direction of the grain growth is considered to be isotropic. Therefore a weld performance map which indicates the orientation of the grain growth can be used to describe the material properties in the weld. In our work, we have chosen a weld map based on the parameters of the MINA model which uses the information of the welding procedure and rules for crystalline growth to predict the orientations, and thus has a good physical foundation. We have compared the measured grain orientations for a realistic weld with the predictions from the model. With this model, only a small number of parameters are used to describe the weld properties, therefore enabling the possibility of a well conditioned refining process to determine the weld map from ultrasonic measurements. We have demonstrated the feasibility of doing this, using a ray tracing model, and both simulated and experimental measurements.

Artificially modified magnetic anisotropy in interconnected nanowire networks.

PubMed

Araujo, Elsie; Encinas, Armando; Velázquez-Galván, Yenni; Martínez-Huerta, Juan Manuel; Hamoir, Gaël; Ferain, Etienne; Piraux, Luc

2015-01-28

Interconnected or crossed magnetic nanowire networks have been fabricated by electrodeposition into a polycarbonate template with crossed cylindrical nanopores oriented ±30° with respect to the surface normal. Tailor-made nanoporous polymer membranes have been designed by performing a double energetic heavy ion irradiation with fixed incidence angles. The Ni and Ni/NiFe nanowire networks have been characterized by magnetometry as well as ferromagnetic resonance and compared with parallel nanowire arrays of the same diameter and density. The most interesting feature of these nanostructured materials is a significant reduction of the magnetic anisotropy when the external field is applied perpendicular and parallel to the plane of the sample. This effect is attributed to the relative orientation of the nanowire axes with the applied field. Moreover, the microwave transmission spectra of these nanowire networks display an asymmetric linewidth broadening, which may be interesting for the development of low-pass filters. Nanoporous templates made of well-defined nanochannel network constitute an interesting approach to fabricate materials with controlled anisotropy and microwave absorption properties that can be easily modified by adjusting the relative orientation of the nanochannels, pore sizes and material composition along the length of the nanowire.

Effect of metallic silver nanoparticles on the alignment and relaxation behaviour of liquid crystalline material in smectic C* phase

NASA Astrophysics Data System (ADS)

Vimal, Tripti; Kumar Gupta, Swadesh; Katiyar, Rohit; Srivastava, Atul; Czerwinski, Michal; Krup, Katarzyna; Kumar, Sandeep; Manohar, Rajiv

2017-09-01

The influence of silver nanoparticles dispersed in a Ferroelectric Liquid Crystal (FLC) on the properties of the resultant composite system has been investigated by thermal, electro-optical, and dielectric methods. We show that the concentration of thiol capped silver nanoparticles is a critical factor in governing the alignment of nanoparticles (NPs) in the host FLC. The orientation of NPs in composite samples affects the ordering of the LC (Liquid Crystal) phase and consequently changes the various phase transition temperatures of the host LC. Formation of self-assembled 2D (two dimensional) arrays of nanoparticles is observed for high concentration of dopant in the LC, oriented perpendicular to the direction of rubbing. We propose that the molecular interaction between the thiol capped NPs and LC molecules is the key factor behind such an arrangement of NPs. Orientation of NPs has affected the relaxation behaviour and various other material parameters, significantly. A noteworthy change in DC conductivity articulates our proposed idea of the formation of 2D array of NPs perpendicular to the direction of rubbing. This comprehensive study endorses the importance of dopant concentration in modifying the properties of the host LC material.

Playgrounds for Free: The Utilization of Used and Surplus Materials in Playground Construction.

ERIC Educational Resources Information Center

Hogan, Paul

This book is a guide to setting up playgrounds from junk materials--used tires, cable reels, inner tubes, and railroad ties, among others--that are child-oriented rather than created primarily for the convenience of adult superintendents. Interwoven with many photographs and plans showing how to use the materials is the author's commentary--part…

Investigating Teacher Learning Supports in High School Biology Curricular Programs to Inform the Design of Educative Curriculum Materials

ERIC Educational Resources Information Center

Beyer, Carrie J.; Delgado, Cesar; Davis, Elizabeth A.; Krajcik, Joseph

2009-01-01

Reform efforts have emphasized the need to support teachers' learning about reform-oriented practices. Educative curriculum materials are one potential vehicle for promoting teacher learning about these practices. Educative curriculum materials include supports that are intended to promote both student "and" teacher learning. However, little is…

The Development of Modular Instructional Materials for Physics for One-Year Vocational Students.

ERIC Educational Resources Information Center

Parsons, Ralph

This report describes a project to develop and test a number of individualized vocational physics modules designed to be laboratory-oriented, written at the lowest reading level, and supplemented with audiovisual materials. The report includes descriptions of the procedures used to develop, pilot test, and disseminate the materials. Each of the…

Free-standing oxide superconducting articles

DOEpatents

Wu, X.D.; Muenchausen, R.E.

1993-12-14

A substrate-free, free-standing epitaxially oriented superconductive film including a layer of a template material and a layer of a ceramic superconducting material is provided together with a method of making such a substrate-free ceramic superconductive film by coating an etchable material with a template layer, coating the template layer with a layer of a ceramic superconductive material, coating the layer of ceramic superconductive material with a protective material, removing the etchable material by an appropriate means so that the etchable material is separated from a composite structure including the template layer.

An anisotropic elastoplasticity model implemented in FLAG

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

Buechler, Miles Allen; Canfield, Thomas R.

2017-10-12

Many metals, including Tantalum and Zirconium, exhibit anisotropic elastoplastic behavior at the single crystal level, and if components are manufactured from these metals through forming processes the polycrystal (component) may also exhibit anisotropic elastoplastic behavior. This is because the forming can induce a preferential orientation of the crystals in the polycrystal. One example is a rolled plate of Uranium where the sti /strong orientation of the crystal (c-axis) tends to align itself perpendicular to the rolling direction. If loads are applied to this plate in di erent orientations the sti ness as well as the ow strength of the materialmore » will be greater in the through thickness direction than in other directions. To better accommodate simulations of such materials, an anisotropic elastoplasticity model has been implemented in FLAG. The model includes an anisotropic elastic stress model as well as an anisotropic plasticity model. The model could represent single crystals of any symmetry, though it should not be confused with a high- delity crystal plasticity model with multiple slip planes and evolutions. The model is most appropriate for homogenized polycrystalline materials. Elastic rotation of the material due to deformation is captured, so the anisotropic models are appropriate for arbitrary large rotations, but currently they do not account for signi cant change in material texture beyond the elastic rotation of the entire polycrystal.« less

3D Simulations of Void collapse in Energetic Materials

NASA Astrophysics Data System (ADS)

Rai, Nirmal Kumar; Udaykumar, H. S.

2017-06-01

Voids present in the microstructure of heterogeneous energetic materials effect the sensitivity towards ignition. It is established that the morphology of voids can play a significant role in sensitivity enhancement of energetic materials. Depending on the void shape, sensitivity can be either increased or decreased under given loading conditions. In the past, effects of different void shapes i.e. triangular, ellipse, cylindrical etc. on the sensitivity of energetic materials have been analyzed. However, most of these studies are performed in 2D and are limited under the plain strain assumption. Axisymmetric studies have also been performed in the past to incorporate the 3D effects, however axisymmetric modeling is limited to only certain geometries i.e. sphere. This work analyzes the effects of various void shapes in three dimensions on the ignition behavior of HMX. Various void shapes are analyzed including spherical, prolate and oblate speheroid oriented at different orientations, etc. Three dimensional void collapse simulations are performed on a single void to quantify the effects void morphology on initiation. A Cartesian grid based Eulerian solver SCIMITAR3D is used to perform the void collapse simulations. Various aspects of void morphology i.e. size, thickness of voids, elongation, orientation etc. are considered to obtain a comprehensive analysis. Also, 2D plane strain calculations are compared with the three dimensional analysis to evaluate the salient differences between 2D and 3D modeling.

MCNP simulations of material exposure experiments (u)

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

Temple, Brian A

2010-12-08

Simulations of proposed material exposure experiments were performed using MCNP6. The experiments will expose ampules containing different materials of interest with radiation to observe the chemical breakdown of the materials. Simulations were performed to map out dose in materials as a function of distance from the source, dose variation between materials, dose variation due to ampule orientation, and dose variation due to different source energy. This write up is an overview of the simulations and will provide guidance on how to use the data in the spreadsheet.

Triphasic Tooling with Small Oriented Diamond Tip for Turning and Smoothing Lightweight Mirrors

NASA Technical Reports Server (NTRS)

Voronov, O. A.; Tompa, G. S.; Kear, B. H.; Veress, V.

2004-01-01

We are developing a new method for the growth of small diamond crystals at very high temperatures and pressures directly from a carbon melt. A prototype "Supercell" has been developed for this purpose. This system is capable of high rate crystal growth in relatively large working volumes. The resulting high quality diamond crystals will be incorporated into a triphasic diamond/titanium carbide/titanium composite tool, with an oriented diamond crystal at its tip. High pressure is needed to prevent degradation of diamond at high temperature, and to ensure the formation of a crack & composite structure. After grinding and polishing, the composite material will be joined to a steel holder, thus forming a diamond-tipped tool for turning and smoothing of a mirror surface. A properly oriented single-crystal diamond cuts and smoothes much better than a conventional polycrystalline diamond crystal. This is because the hardness depends on crystallographic orientation-the difference corresponds to 60-100 GPa on the Knoop scale. Our goal is to achieve surface roughness of about 1 nm, which will be accomplished by precision cutting and smoothing. The hardness of the functionally-graded diamond/titanium carbide/titanium composite tool varies from 100 GPa at its tip to 15 GPa at its base. Previous work has shown that the mass of machined material using an oriented-diamond tool is much larger than that for a standard diamond-metal composite tool.

Praseodymium Cuprate Thin Film Cathodes for Intermediate Temperature Solid Oxide Fuel Cells: Roles of Doping, Orientation, and Crystal Structure.

PubMed

Mukherjee, Kunal; Hayamizu, Yoshiaki; Kim, Chang Sub; Kolchina, Liudmila M; Mazo, Galina N; Istomin, Sergey Ya; Bishop, Sean R; Tuller, Harry L

2016-12-21

Highly textured thin films of undoped, Ce-doped, and Sr-doped Pr 2 CuO 4 were synthesized on single crystal YSZ substrates using pulsed laser deposition to investigate their area-specific resistance (ASR) as cathodes in solid-oxide fuel cells (SOFCs). The effects of T' and T* crystal structures, donor and acceptor doping, and a-axis and c-axis orientation on ASR were systematically studied using electrochemical impedance spectroscopy on half cells. The addition of both Ce and Sr dopants resulted in improvements in ASR in c-axis oriented films, as did the T* crystal structure with the a-axis orientation. Pr 1.6 Sr 0.4 CuO 4 is identified as a potential cathode material with nearly an order of magnitude faster oxygen reduction reaction kinetics at 600 °C compared to thin films of the commonly studied cathode material La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3-δ . Orientation control of the cuprate films on YSZ was achieved using seed layers, and the anisotropy in the ASR was found to be less than an order of magnitude. The rare-earth doped cuprate was found to be a versatile system for study of relationships between bulk properties and the oxygen reduction reaction, critical for improving SOFC performance.

On Developing Content-Oriented Theories Taking Biological Evolution as an Example

ERIC Educational Resources Information Center

Andersson, Bjorn; Wallin, Anita

2006-01-01

Both in Europe and the United States there is a growing interest in design research. One example is the design and validation of topic-oriented teaching-learning sequences. This research may be said to have two objectives. One is to design and test "useful products", such as teachers guides and study material for students, which may be…

A Parent Involvement Model for Use with Limited English Proficient High School Students: The Vocationally Oriented Bilingual Curriculum. English-Vietnamese.

ERIC Educational Resources Information Center

Trinity Coll., Washington, DC.

Materials for use by the parents of native Vietnamese-speaking high school students in a vocationally-oriented bilingual secondary program include a series of home lessons, provided simultaneously in English and Vietnamese and designed to be done with the high school student. The lessons concern back-to-school night, understanding American…

Latin America Report

DTIC Science & Technology

1986-12-02

GOVERNOR’S CABINET CALLED BUSINESS-ORIENTED Mexico City PROCESO in Spanish No 519, 13 Oct 86 pp 10-13 [Article by Francisco Ortiz Pinchetti] [Text...news agency transmissions and broadcasts. Materials from foreign- language sources are translated; those from English- language sources are transcribed...82 Chihuahua Governor’s Cabinet Called Business-Oriented (Francisco Ortiz Pinchetti; PROCESO , No 519, 13 Oct 86).. 84 NICARAGUA Pastora on

Procurement of Library Materials in the Federal Government; An Orientation Aid Prepared for the Federal Library Committee.

ERIC Educational Resources Information Center

Falk, Leslie K.

This handbook is designed primarily as a general orientation aid, not an operation manual. It presents the background (mainly regulatory) of Federal procurement work, details, devices and tactics found to be successful, and calls attention to special sources of supply. Although planned as an aid for librarians who are engaged in Federal…

A simple method for orienting silk and other flexible fibres in transmission electron microscopy specimens.

PubMed

Trancik, J E; Czernuszka, J T; Merriman, C; Viney, C

2001-09-01

When microstructures are characterized by transmission electron microscopy (TEM), the interpretation of results is facilitated if the material can be sectioned in defined orientations. In the case of fibres, it is especially useful if transverse and longitudinal sections can be obtained reliably. Here we describe a procedure for orienting spider silk and other flexible fibres for TEM investigation. Prior to embedding in epoxy resin, the silk is wound around a notched support made from polyester film. No glue is required. After the silk and its supporting film have been embedded and the resin has been cured the film can be peeled away to reveal nearly perfectly orientated silk threads. Both transverse and longitudinal sections can then be cut with a microtome. The method can be extended to obtain sections at any intermediate orientation.

Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor-Acceptor Conjugated Polymers.

PubMed

Ayzner, Alexander L; Mei, Jianguo; Appleton, Anthony; DeLongchamp, Dean; Nardes, Alexandre; Benight, Stephanie; Kopidakis, Nikos; Toney, Michael F; Bao, Zhenan

2015-12-30

Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wave functions, they often form semicrystalline thin films. In this work, we aim to understand whether distribution of crystallographic orientations affects exciton diffusion using a low-band-gap polymer backbone motif that is representative of the donor/acceptor copolymer class. Using the fact that the polymer side chain can tune the dominant crystallographic orientation in the thin film, we have measured the quenching of polymer photoluminescence, and thus the extent of exciton dissociation, as a function of crystal orientation with respect to a quenching substrate. We find that the crystallite orientation distribution has little effect on the average exciton diffusion length. We suggest several possibilities for the lack of correlation between crystallographic texture and exciton transport in semicrystalline conjugated polymer films.

Bio-inspired dental fillings

NASA Astrophysics Data System (ADS)

Deyhle, Hans; Bunk, Oliver; Buser, Stefan; Krastl, Gabriel; Zitzmann, Nicola U.; Ilgenstein, Bernd; Beckmann, Felix; Pfeiffer, Franz; Weiger, Roland; Müller, Bert

2009-08-01

Human teeth are anisotropic composites. Dentin as the core material of the tooth consists of nanometer-sized calcium phosphate crystallites embedded in collagen fiber networks. It shows its anisotropy on the micrometer scale by its well-oriented microtubules. The detailed three-dimensional nanostructure of the hard tissues namely dentin and enamel, however, is not understood, although numerous studies on the anisotropic mechanical properties have been performed and evaluated to explain the tooth function including the enamel-dentin junction acting as effective crack barrier. Small angle X-ray scattering (SAXS) with a spatial resolution in the 10 μm range allows determining the size and orientation of the constituents on the nanometer scale with reasonable precision. So far, only some dental materials, i.e. the fiber reinforced posts exhibit anisotropic properties related to the micrometer-size glass fibers. Dental fillings, composed of nanostructures oriented similar to the natural hard tissues of teeth, however, do not exist at all. The current X-ray-based investigations of extracted human teeth provide evidence for oriented micro- and nanostructures in dentin and enamel. These fundamental quantitative findings result in profound knowledge to develop biologically inspired dental fillings with superior resistance to thermal and mechanical shocks.

Physical properties and microstructure study of stainless steel 316L alloy fabricated by selective laser melting

NASA Astrophysics Data System (ADS)

Islam, Nurul Kamariah Md Saiful; Harun, Wan Sharuzi Wan; Ghani, Saiful Anwar Che; Omar, Mohd Asnawi; Ramli, Mohd Hazlen; Ismail, Muhammad Hussain

2017-12-01

Selective Laser Melting (SLM) demonstrates the 21st century's manufacturing infrastructure in which powdered raw material is melted by a high energy focused laser, and built up layer-by-layer until it forms three-dimensional metal parts. SLM process involves a variation of process parameters which affects the final material properties. 316L stainless steel compacts through the manipulation of building orientation and powder layer thickness parameters were manufactured by SLM. The effect of the manipulated parameters on the relative density and dimensional accuracy of the 316L stainless steel compacts, which were in the as-build condition, were experimented and analysed. The relationship between the microstructures and the physical properties of fabricated 316L stainless steel compacts was investigated in this study. The results revealed that 90° building orientation has higher relative density and dimensional accuracy than 0° building orientation. Building orientation was found to give more significant effect in terms of dimensional accuracy, and relative density of SLM compacts compare to build layer thickness. Nevertheless, the existence of large number and sizes of pores greatly influences the low performances of the density.

Double Stokes-Mueller polarimetry in KTP (Potassium Titanyl Phosphate) crystal

NASA Astrophysics Data System (ADS)

Shaji, Chitra; S B, Sruthil Lal; Sharan, Alok

2017-04-01

Ultra-structural properties of material are being probed by Double Stokes-Mueller polarimetry (DSMP) technique. It makes use of higher dimensions of Stokes vector (9 X 1) and Mueller matrix (4 X9) to characterize the nonlinear optical properties of a material. Second harmonic generation (SHG) at 532nm using 1064nm as fundamental cw beam from Nd: YAG laser in type II phase matched KTP (Potassium Titanyl Phosphate) crystal is studied using DSMP. The experimental measurements for determining double Mueller matrix are carried out in the ``Polarization In Polarization Out'' (PIPO) arrangement. Nine input polarization states are incident on the sample and the linear Stokes vector of the emerging light from the sample is measured. The KTP crystal is oriented such that the SHG signal efficiency at the incident horizontal and vertical polarizations is high as compared to diagonal polarization states. The susceptibility tensor components and the phase difference between them at this orientation are determined from the double Mueller matrix elements. These determined values give information regarding the crystal axis orientations. To our knowledge, this is the first report of the use of DSMP technique to determine the crystal orientations of a biaxial crystal.

Erosion Data from the MISSE 8 Polymers Experiment After 2 Years of Space Exposure on the International Space Station

NASA Technical Reports Server (NTRS)

de Groh, Kim K.; Banks, Bruce A.; Asmar, Olivia C.; Yi, Grace T.; Mitchell, Gianna G.; Guo, Aobo; Sechkar, Edward A.

2016-01-01

The Polymers Experiment was exposed to the low Earth orbit (LEO) space environment for 2.14 and 2.0 years as part of the Materials International Space Station Experiment 8 (MISSE 8) and the Optical Reflector Materials Experiment-III (ORMatE-III), respectively. The experiment contained 42 samples, which were flown in either ram, wake, or zenith orientations. The primary objective was to determine the effect of solar exposure on the atomic oxygen erosion yield (Ey) of fluoropolymers. This paper provides an overview of the experiment with details on the polymers flown, the characterization techniques used, the atomic oxygen fluence for each exposure orientation, and the LEO Ey results. The Ey values for the fluoropolymers range from 1.45 x 10(exp -25) cm(exp 3)/atom for white Tedlar Registered Trademark? (polyvinyl fluoride with white titanium dioxide pigment) flown in the ram orientation to 6.32 x 10(exp -24) cm(exp 3)/atom for aluminized-Teflon Registered Trademark? fluorinated ethylene propylene (Al-FEP) flown in the zenith orientation. Erosion yield data for FEP flown in ram, wake and zenith orientations are compared, and the Ey was found to be highly dependent on orientation, hence environmental exposure. Teflon FEP had an order of magnitude higher Ey when flown in the zenith direction (6.32 x10(exp -24) cm(exp3)/atom) as compared to the ram direction (2.37 x 10(exp -25) cm(exp 3)/atom). The Ey of FEP was found to increase with a direct correlation to the solar exposure/AO fluence ratio showing the effect of solar radiation and/or heating due to solar exposure on FEP erosion. In addition, back-surface carbon painted FEP (C-FEP) flown in the zenith orientation had a significantly higher Ey than clear FEP or Al-FEP further indicating that heating has a significant impact on the erosion of FEP, particularly in the zenith orientation.

Prenatal Material Hardships and Infant Regulatory Capacity at 10 Months Old in Low-Income Hispanic Mother-Infant Pairs.

PubMed

Fuller, Anne; Messito, Mary Jo; Mendelsohn, Alan L; Oyeku, Suzette O; Gross, Rachel S

2018-05-02

Prenatal maternal stresses have been associated with infant temperament patterns linked to later behavioral difficulties. Material hardships, defined as inability to meet basic needs, are important prenatal stressors. Our objective was to determine the associations between prenatal material hardships and infant temperament at 10 months. This was a longitudinal study of mother-infant pairs in a randomized controlled trial of a primary care-based early obesity prevention program (Starting Early). Independent variables representing material hardship were: housing disrepair, food insecurity, difficulty paying bills and neighborhood stress (neighborhood safety). Dependent variables representing infant temperament were assessed using questions from three subscales of the Infant Behavior Questionnaire: orienting/regulatory capacity, negative affect, and surgency/extraversion. We used linear regression to investigate associations between individual and cumulative hardships and each temperament domain, adjusting for confounders, and testing for depression as a moderator. 412 mother-infant pairs completed 10 month assessments. 32% reported food insecurity, 26% difficulty paying bills, 35% housing disrepair and 9% neighborhood stress. In adjusted analyses, food insecurity was associated with lower orienting/regulatory capacity scores (B=-0.25, 95% CI -0.47, -0.04), as were neighborhood stress (B=-0.50, 95% CI -0.83, -0.16) and experiencing 3-4 hardships (compared with none) (B=-0.54, 95% CI -0.83, -0.21). For neighborhood stress, the association was stronger among infants of mothers with prenatal depressive symptoms (interaction term p=0.06). Prenatal material hardships were associated with lower orienting/regulatory capacity. These findings support the need for further research exploring how temperament relates to child behavior, and for policies to reduce prenatal material hardships. Copyright © 2018. Published by Elsevier Inc.

Defect characterization by inductive heated thermography

NASA Astrophysics Data System (ADS)

Noethen, Matthias; Meyendorf, Norbert

2012-05-01

During inductive-thermographic inspection, an eddy current of high intensity is induced into the inspected material and the thermal response is detected by an infrared camera. Anomalies in the surface temperature during and after inductive heating correspond to inhomogeneities in the material. A finite element simulation of the surface crack detection process using active thermography with inductive heating has been developed. The simulation model is based on the finite element software ANSYS. The simulation tool was tested and used for investigations on steel components with different longitudinal orientated cracks, varying in shape, width and height. This paper focuses on surface connected longitudinal orientated cracks in austenitic steel. The results show that depending on the excitation frequency the temperature distribution of the material under test are different and a possible way to measure the depth of the crack will be discussed.

Contactor/filter improvements

DOEpatents

Stelman, David

1989-01-01

A contactor/filter arrangement for removing particulate contaminants from a gaseous stream includes a housing having a substantially vertically oriented granular material retention member with upstream and downstream faces, a substantially vertically oriented microporous gas filter element, wherein the retention member and the filter element are spaced apart to provide a zone for the passage of granular material therethrough. The housing further includes a gas inlet means, a gas outlet means, and means for moving a body of granular material through the zone. A gaseous stream containing particulate contaminants passes through the gas inlet means as well as through the upstream face of the granular material retention member, passing through the retention member, the body of granular material, the microporous gas filter element, exiting out of the gas outlet means. Disposed on the upstream face of the filter element is a cover screen which isolates the filter element from contact with the moving granular bed and collects a portion of the particulates so as to form a dust cake having openings small enough to exclude the granular material, yet large enough to receive the dust particles. In one embodiment, the granular material is comprised of prous alumina impregnated with CuO, with the cover screen cleaned by the action of the moving granular material as well as by backflow pressure pulses.

Damage, Self-Healing, and Hysteresis in Spider Silks

PubMed Central

De Tommasi, D.; Puglisi, G.; Saccomandi, G.

2010-01-01

Abstract In this article, we propose a microstructure-based continuum model to describe the material behavior of spider silks. We suppose that the material is composed of a soft fraction with entropic elasticity and a hard, damageable fraction. The hard fraction models the presence of stiffer, crystal-rich, oriented regions and accounts for the effect of softening induced by the breaking of hydrogen bonds. To describe the observed presence of crystals with different size, composition, and orientation, this hard fraction is modeled as a distribution of materials with variable properties. The soft fraction describes the remaining regions of amorphous material and is here modeled as a wormlike chain. During stretching, we consider the effect of bond-breaking as a transition from the hard- to the soft-material phase. As we demonstrate, a crucial effect of bond-breaking that accompanies the softening of the material is an increase in contour length associated with chains unraveling. The model describes also the self-healing properties of the material by assuming partial bond reconnection upon unloading. Despite its simplicity, the proposed mechanical system reproduces the main experimental effects observed in cyclic loading of spider silks. Moreover, our approach is amenable to two- or three-dimensional extensions and may prove to be a useful tool in the field of microstructure optimization for bioinspired materials. PMID:20441758

Texture and anisotropy in ferroelectric lead metaniobate

NASA Astrophysics Data System (ADS)

Iverson, Benjamin John

Ferroelectric lead metaniobate, PbNb2O6, is a piezoelectric ceramic typically used because of its elevated Curie temperature and anisotropic properties. However, the piezoelectric constant, d33, is relatively low in randomly oriented ceramics when compared to other ferroelectrics. Crystallographic texturing is often employed to increase the piezoelectric constant because the spontaneous polarization axes of grains are better aligned. In this research, crystallographic textures induced through tape casting are distinguished from textures induced through electrical poling. Texture is described using multiple quantitative approaches utilizing X-ray and neutron time-of-flight diffraction. Tape casting lead metaniobate with an inclusion of acicular template particles induces an orthotropic texture distribution. Templated grain growth from seed particles oriented during casting results in anisotropic grain structures. The degree of preferred orientation is directly linked to the shear behavior of the tape cast slurry. Increases in template concentration, slurry viscosity, and casting velocity lead to larger textures by inducing more particle orientation in the tape casting plane. The maximum 010 texture distributions were two and a half multiples of a random distribution. Ferroelectric texture was induced by electrical poling. Electric poling increases the volume of material oriented with the spontaneous polarization direction in the material. Samples with an initial paraelectric texture exhibit a greater change in the domain volume fraction during electrical poling than randomly oriented ceramics. In tape cast samples, the resulting piezoelectric response is proportional to the 010 texture present prior to poling. This results in property anisotropy dependent on initial texture. Piezoelectric properties measured on the most textured ceramics were similar to those obtained with a commercial standard.

Biaxially textured composite substrates

DOEpatents

Groves, James R.; Foltyn, Stephen R.; Arendt, Paul N.

2005-04-26

An article including a substrate, a layer of a metal phosphate material such as an aluminum phosphate material upon the surface of the substrate, and a layer of an oriented cubic oxide material having a rock-salt-like structure upon the metal phosphate material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon a layer of a buffer material such as a SrTi.sub.x Ru.sub.1-x O.sub.3 layer.

Ion-beam-assisted deposition of Au nanocluster/Nb 2O 5 thin films with nonlinear optical properties

NASA Astrophysics Data System (ADS)

Cotell, C. M.; Schiestel, S.; Carosella, C. A.; Flom, S.; Hubler, G. K.; Knies, D. L.

1997-05-01

Gold nanocluster thin films (˜ 200 nm thickness) consisting of metal clusters ˜ 5 nm in size embedded in a matrix of Nb 2O 5 were deposited by ion beam-assisted deposition (IBAD) by coevaporation of Au and Nb with O 2+ ion bombardment. The microstructure and optical characteristics of these films were examined as-deposited and after annealing at 600°C. Annealing crystallized the amorphous oxide matrix and ripened the nanoclusters. A strong linear absorption at the wavelength of the surface plasmon resonance for Au developed as a result of annealing. The linear optical behavior was modeled using Mie scattering theory. Good agreement was found between the nanocluster sizes predicted by the theory and the particle sizes observed experimentally using transmission electron microscopy (TEM). The nonlinear optical (NLO) properties of the nanocluster films were probed experimentally using degenerate four wave mixing and nonlinear transmission. The wavelength was near the peak of the surface plasmon resonance as measured by VIS/UV spectroscopy. Values of | χxxxx(3)| were 7.3 × 10 -8 and 3.0 × 10 -10 esu for annealed and unannealed samples, respe The dominant mechanism for the nonlinear response was change in dielectric constant due to the generation of a distribution of hot, photoexcited electrons.

Cooperative Programs in Residential Outdoor Environmental Education: Teacher's Materials Packet.

ERIC Educational Resources Information Center

Marin County Superintendent of Schools, Corte Madera, CA.

Serving as teacher orientation materials for the cooperative programs in residential outdoor education located in Marin County, California, this guide includes the following: (1) "This I Believe" (a philosophical statement on outdoor environmental education); (2) "Outdoor Science and Conservation Education Report" (a brief…

Meat and Poultry Processing. Teacher Edition.

ERIC Educational Resources Information Center

Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

This curriculum guide contains instructional materials for a program that provides students with job skills in meat and poultry processing. The curriculum consists of 10 units that cover the following material: orientation to meat and poultry processing; maintaining plant facilities; equipment and equipment maintenance; purchasing livestock for…

Comparison of high temperature, high frequency core loss and dynamic B-H loops of a 2V-49Fe-49Co and a grain oriented 3Si-Fe alloy

NASA Technical Reports Server (NTRS)

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1992-01-01

The design of power magnetic components such as transformers, inductors, motors, and generators, requires specific knowledge about the magnetic and electrical characteristics of the magnetic materials used in these components. Limited experimental data exists that characterizes the performance of soft magnetic materials for the combined conditions of high temperature and high frequency over a wide flux density range. An experimental investigation of a 2V-49-Fe-49Co (Supermendur) and a grain oriented 3 Si-Fe (Magnesil) alloy was conducted over the temperature range of 23 to 300 C and frequency range of 0.1 to 10 kHz. The effects of temperature, frequency, and maximum flux density on the core loss and dynamic B-H loops for sinusoidal voltage excitation conditions are examined for each of these materials. A comparison of the core loss of these two materials is also made over the temperature and frequency range investigated.

Influence of hydride orientation on fracture toughness of CWSR Zr-2.5%Nb pressure tube material between RT and 300 °C

NASA Astrophysics Data System (ADS)

Sharma, Rishi K.; Sunil, Saurav; Kumawat, B. K.; Singh, R. N.; Tewari, Asim; Kashyap, B. P.

2017-05-01

An experimental setup was designed, fabricated and used to form radial hydrides in Zr-2.5%Nb alloy pressure tube spool. The design of setup was based on ensuring a hoop stress in the spool greater than threshold stress for reorientation of hydrides in this alloy, which was achieved by manipulating the thermal expansion coefficient of the plunger and pressure tube material and diametral interference between them. The experimental setup was loaded on a universal testing machine (UTM) fitted with an environmental chamber and subjected to a temperature cycle for the stress reorientation treatment. The metallographic examination of the hydrogen charged spools subjected to stress re-orientation treatment using this set up revealed formation of predominantly radial hydrides. The variation of fracture toughness of material containing radial hydride with test temperature showed typical 'S' curve behavior with transition temperatures more than that of the material containing circumferential hydride.

The high temperature creep behavior of oxides and oxide fibers

NASA Technical Reports Server (NTRS)

Jones, Linda E.; Tressler, Richard E.

1991-01-01

A thorough review of the literature was conducted on the high-temperature creep behavior of single and polycrystalline oxides which potentially could serve as fiber reinforcements in ceramics or metal matrix applications. Sapphire when oriented with the basal plane perpendicular to the fiber axis (c-axis oriented) is highly creep resistant at temperatures in excess of 1600 C and applied loads of 100 MPa and higher. Pyramidal slip is preferentially activated in sapphire under these conditions and steady-state creep rates in the range of 10(exp -7) to 10 (exp -8)/s were reported. Data on the creep resistance of polycrystalline beryllia suggest that C-axiz oriented single crystal beryllia may be a viable candidate as a fiber reinforcement material; however, the issure of fabricability and moisture sensitivity must be addressed for this material. Yttrium aluminum garnet (YAG) also appears to be a fiber candidate material having a high resistance to creep which is due to it's complex crystal structure and high Peierl resistance. The high creep resistance of garnet suggests that there may be other complex ternary oxides such as single crystal mullite which may also be candidate materials for fiber reinforcements. Finally, CVD and single crystal SiC, although not oxides, do possess a high resistance to creep in the temperature range between 1550 and 1850 C and under stresses of 110 to 220 MPa. From a review of the literature, it appears that for high creep resistant applications sapphire, silicon carbide, yttrium aluminum garnet, mullite, and beryllia are desirable candidate materials which require further investigation.

Determination of orthotropic mechanical properties of 3D printed parts for structural health monitoring

NASA Astrophysics Data System (ADS)

Poissenot-Arrigoni, Bastien; Scheyer, Austin; Anton, Steven R.

2017-04-01

The evolution of additive manufacturing has allowed engineers to use 3D printing for many purposes. As a natural consequence of the 3D printing process, the printed object is anisotropic. As part of an ongoing project to embed piezoelectric devices in 3D printed structures for structural health monitoring (SHM), this study aims to find the mechanical properties of the 3D printed material and the influence of different external factors on those properties. The orthotropic mechanical properties of a 3D printed structure are dependent on the printing parameters used to create the structure. In order to develop an orthotropic material model, mechanical properties will be found experimentally from additively manufactured samples created from polylactic acid (PLA) using a consumer-level fused deposition modeling (FDM) printer; the Lulzbot TAZ 6. Nine mechanical constants including three Young's moduli, three Poisson's ratios, and three shear moduli are needed to fully describe the 3D elastic behavior of the material. Printed specimens with different raster orientations and print orientations allow calculation of the different material constants. In this work, seven of the nine mechanical constants were found. Two shear moduli were unable to be measured due to difficulties in printing two of the sample orientations. These mechanical properties are needed in order to develop orthotropic material models of systems employing 3D printed PLA. The results from this paper will be used to create a model of a piezoelectric transducer embedded in a 3D printed structure for structural health monitoring.

A Further Evaluation of Bridge Roles: Regional and National Organizations for Dissemination of Computer-Oriented Curriculum Materials for Higher Education.

ERIC Educational Resources Information Center

Dank, Joseph R.

Several things must be done before a critical mass of computer-based materials can form a library. Existing materials must be upgraded, and made accessible, flexible and customized for individual users. Their mobility must be increased by reconciling inter-system differences and by providing necessary skills, resources and reward structures.…

High-piezoelectric behavior of c-axis-oriented lead zirconate titanate thin films with composition near the morphotropic phase boundary

NASA Astrophysics Data System (ADS)

Fu, Desheng; Suzuki, Hisao; Ogawa, Takeshi; Ishikawa, Kenji

2002-05-01

The piezoelectric responses of c-axis-oriented Pb(Zr0.53Ti0.47)O3 (PZT) thin films have been studied by measuring the stress-induced charge with an accurate charge integrator. These measurements reveal that the c-axis-oriented PZT films have high values of d33, which are several times those of ceramic materials. The intrinsic d33 values of poled films are about 680 and 800 pC/N for the c-axis-oriented films on Si and MgO single-crystal substrates, respectively. It shows that the thin-film deposition technique opens an approach for exploring the potential superior properties of PZT near the morphotropic phase boundary.

Development Biology Worksheet Oriented Accelerated Learning on Plantae and Ecosystems for 10th-Grade Senior High School Students

NASA Astrophysics Data System (ADS)

Dipuja, D. A.; Lufri, L.; Ahda, Y.

2018-04-01

The problem that found are learning outcomes student is low on the plantae and ecosystems. Students less motivated and passive learning because learning is teacher center and teaching materials not facilitate student. Therefore, it is necessary to design a worksheet oriented accelerated learning. Accelerated learning approach that can improve motivation and learning activities. The purpose of the research was to produce worksheet oriented accelerated learning on plantae and ecosystems. This research is designed as a research and development by using Plomp model, consists of the preliminary, prototyping, and assessment phase. Data was collected through questionnaires, observation sheet, test, and documentation. The results of the research was worksheet oriented accelerated learning on plantae and ecosystems is very valid.

Construction of Nanowire Heterojunctions: Photonic Function-Oriented Nanoarchitectonics.

PubMed

Li, Yong Jun; Yan, Yongli; Zhao, Yong Sheng; Yao, Jiannian

2016-02-10

Nanophotonics has received broad research interest because it may provide an alternative opportunity to overcome the fundamental limitations of electronic circuits. So far, diverse photonic functions, such as light generation, modulation, and detection, have been realized based on various nano-materials. The exact structural features of these material systems, including geometric characteristics, surface morphology, and material composition, play a key role in determining the photonic functions. Therefore, rational designs and constructions of materials on both morphological and componential levels, namely nanoarchitectonics, are indispensable for any photonic device with specific functionalities. Recently, a series of nanowire heterojunctions (NWHJs), which are usually made from two or more kinds of material compositions, were constructed for novel photonic applications based on various interactions between different materials at the junctions, for instance, energy transfer, exciton-plasmon coupling, or photon-plasmon coupling. A summary of these works is necessary to get a more comprehensive understanding of the relationship between photonic functions and architectonics of NWHJs, which will be instructive for designing novel photonic devices towards integrated circuits. Here, photonic function oriented nanoarchitectonics based on recent breakthroughs in nanophotonic devices are discussed, with emphasis on the design mechanisms, fabrication strategies, and excellent performances. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Orientation control and domain structure analysis of {100}-oriented epitaxial ferroelectric orthorhombic HfO{sub 2}-based thin films

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

Katayama, Kiliha; Shimizu, Takao; Sakata, Osami

2016-04-07

Orientation control of {100}-oriented epitaxial orthorhombic 0.07YO{sub 1.5}-0.93HfO{sub 2} films grown by pulsed laser deposition was investigated. To achieve in-plane lattice matching, indium tin oxide (ITO) and yttria-stabilized zirconia (YSZ) were selected as underlying layers. We obtained (100)- and (001)/(010)-oriented films on ITO and YSZ, respectively. Ferroelastic domain formation was confirmed for both films by X-ray diffraction using the superlattice diffraction that appeared only for the orthorhombic symmetry. The formation of ferroelastic domains is believed to be induced by the tetragonal–orthorhombic phase transition upon cooling the films after deposition. The present results demonstrate that the orientation of HfO{sub 2}-based ferroelectricmore » films can be controlled in the same manner as that of ferroelectric films composed of conventional perovskite-type material such as Pb(Zr, Ti)O{sub 3} and BiFeO{sub 3}.« less

Anisotropy, size, and aspect ratio effects on micropillar compression of Al-SiC nanolaminate composites

DOE PAGES

Mayer, C. R.; Yang, L. W.; Singh, S. S.; ...

2016-05-20

Metal-ceramic nanolaminate composites show promise as high strength and toughness materials. Micropillar compression was used to characterize the mechanical behavior of AlSiC multilayers in different orientations including loading at 0°, 45° and 90° with respect to the direction of the layers. The 0° orientation showed the highest strength while the 45° orientation showed the lowest strength. Each orientation showed unique deformation behavior. Effects of pillar size and aspect ratio were also studied. Higher compressive strengths were observed in smaller pillars for all orientations. This effect was shown to be due to a lower probability of flaws using Weibull statistics. Additionally,more » changes in the aspect ratio was shown to have no significant effect on the behavior except an increase in the strain to failure in the 0° orientation. In conclusion, finite element analysis (FEA) was used to simulate and understand the effect of these parameters on the deformation behavior.« less

Tetrahedral Arrangements of Perylene Bisimide Columns via Supramolecular Orientational Memory.

PubMed

Sahoo, Dipankar; Peterca, Mihai; Aqad, Emad; Partridge, Benjamin E; Heiney, Paul A; Graf, Robert; Spiess, Hans W; Zeng, Xiangbing; Percec, Virgil

2017-01-24

Chiral, shape, and liquid crystalline memory effects are well-known to produce commercial macroscopic materials with important applications as springs, sensors, displays, and memory devices. A supramolecular orientational memory effect that provides complex nanoscale arrangements was only recently reported. This supramolecular orientational memory was demonstrated to preserve the molecular orientation and packing within supramolecular units of a self-assembling cyclotriveratrylene crown at the nanoscale upon transition between its columnar hexagonal and Pm3̅n cubic periodic arrays. Here we report the discovery of supramolecular orientational memory in a dendronized perylene bisimide (G2-PBI) that self-assembles into tetrameric crowns and subsequently self-organizes into supramolecular columns and spheres. This supramolecular orientation memory upon transition between columnar hexagonal and body-centered cubic (BCC) mesophases preserves the 3-fold cubic [111] orientations rather than the 4-fold [100] axes, generating an unusual tetrahedral arrangement of supramolecular columns. These results indicate that the supramolecular orientational memory concept may be general for periodic arrays of self-assembling dendrons and dendrimers as well as for other periodic and quasiperiodic nanoscale organizations comprising supramolecular spheres, generated from other organized complex soft matter including block copolymers and surfactants.

Solidification rate influence on orientation and mechanical properties of MAR-M-246+Hf

NASA Technical Reports Server (NTRS)

Hamilton, D.

1983-01-01

The influence of solidification rates on the orientation and mechanical properties of MAR-M-246+Hf was studied. The preferred orientation was found to be (001) for single crystals, with all samples with 45 degrees of (001). Tensile tests were performed at room temperature. The anisotropy of directionally solidified MAR-M-246+Hf was demonstrated by gage section deformation. Dendrite arm spacing and crystal growth were found to depend on solidification rates and source material conditions. The greatest strength occurred at lower solidification rates. Some single crystals were grown by control of growth rates without seeding.

Terahertz spectroscopic analysis of crystal orientation in polymers

NASA Astrophysics Data System (ADS)

Azeyanagi, Chisato; Kaneko, Takuya; Ohki, Yoshimichi

2018-05-01

Terahertz time-domain spectroscopy (THz-TDS) is attracting keen attention as a new spectroscopic tool for characterizing various materials. In this research, the possibility of analyzing the crystal orientation in a crystalline polymer by THz-TDS is investigated by measuring angle-resolved THz absorption spectra for sheets of poly(ethylene terephthalate), poly(ethylene naphthalate), and poly(phenylene sulfide). The resultant angle dependence of the absorption intensity of each polymer is similar to that of the crystal orientation examined using pole figures of X-ray diffraction. More specifically, THz-TDS can indicate the alignment of molecules in polymers.

Career Oriented Mathematics, Student's Manual. [Includes Owning an Automobile and Driving as a Career; Retail Sales; Measurement; and Area-Perimeter.

ERIC Educational Resources Information Center

Mahaffey, Michael L.; McKillip, William D.

This volume includes student manuals for four units in the Career Oriented Mathematics Program, which was developed to improve computational abilities and attitudes of secondary students by presenting the material in a job-relevant context. The units are titled: (1) Owning an Automobile and Driving as a Career, (2) Retail Sales, (3) Measurement,…

Vertically oriented graphene bridging active-layer/current-collector interface for ultrahigh rate supercapacitors.

PubMed

Bo, Zheng; Zhu, Weiguang; Ma, Wei; Wen, Zhenhai; Shuai, Xiaorui; Chen, Junhong; Yan, Jianhua; Wang, Zhihua; Cen, Kefa; Feng, Xinliang

2013-10-25

Dense networks of graphene nanosheets standing vertically on a current collector can work as numerous electrically conductive bridges to facilitate charge transport and mitigate the constriction/spreading resistance at the interface between the active material and the current collector. The vertically oriented graphene-bridged supercapacitors present excellent rate and power capabilities. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A REGIONAL INSTITUTE TO AID IMPROVEMENT OF INSTRUCTIONAL PRACTICES, MATERIALS AND STUDENT EXPERIENCES FOR COORDINATORS AND INSTRUCTORS OF VOCATIONAL ORIENTATION PROGRAMS. FINAL REPORT.

ERIC Educational Resources Information Center

BLAIR, MARGARET; AND OTHERS

APPROXIMATELY 100 EDUCATORS FROM FIVE STATES AND THE VIRGIN ISLANDS PARTICIPATED IN AN INSTITUTE TO HELP INSTRUCTIONAL AND GUIDANCE PERSONNEL IMPROVE THE VOCATIONAL ORIENTATION OF HIGH SCHOOL STUDENTS WHO ARE PREPARING TO ENTER THE WORLD OF WORK. THE AGENDA CONSISTED OF SPEECHES ON VOCATIONS, GROUP SESSIONS TO DISCUSS VOCATIONAL PROGRAM…

A Parent Involvement Model for Use with Limited English Proficient High School Students: The Vocationally Oriented Bilingual Curriculum. English-Lao.

ERIC Educational Resources Information Center

Trinity Coll., Washington, DC.

Materials for use by the parents of native Lao-speaking high school students in a vocationally-oriented bilingual secondary program include a series of home lessons, provided simultaneously in English and Lao and designed to be done with the high school student. The lessons concern back-to-school night, understanding American schools, the…

A Parent Involvement Model for Use with Limited English Proficient High School Students: The Vocationally Oriented Bilingual Curriculum. English-Khmer.

ERIC Educational Resources Information Center

Trinity Coll., Washington, DC.

Materials for use by the parents of native Khmer-speaking high school students in a vocationally-oriented bilingual secondary program include a series of home lessons, provided simultaneously in English and Khmer and designed to be done with the high school student. The lessons concern back-to-school night, understanding American schools, the…

Rotating magnetizations in electrical machines: Measurements and modeling

NASA Astrophysics Data System (ADS)

Thul, Andreas; Steentjes, Simon; Schauerte, Benedikt; Klimczyk, Piotr; Denke, Patrick; Hameyer, Kay

2018-05-01

This paper studies the magnetization process in electrical steel sheets for rotational magnetizations as they occur in the magnetic circuit of electrical machines. A four-pole rotational single sheet tester is used to generate the rotating magnetic flux inside the sample. A field-oriented control scheme is implemented to improve the control performance. The magnetization process of different non-oriented materials is analyzed and compared.

The Influence of Emotional Difficulty, Parent-Child Relationship, Peer Relationships, Materially-Oriented and Appearance-Oriented Attitudes on Adolescent Problem Behavior

ERIC Educational Resources Information Center

Bae, Sung Man

2016-01-01

This study explored predictors of adolescent problem behavior utilizing panel data from the National Youth Policy Institute. Data were collected from June 2013 to August 2013 from 3195 middle school students living in 15 cities of South Korea. Data were analysed using hierarchical regression in two steps. The first step included gender and school…

Designing Interactive Electronic Module in Chemistry Lessons

NASA Astrophysics Data System (ADS)

Irwansyah, F. S.; Lubab, I.; Farida, I.; Ramdhani, M. A.

2017-09-01

This research aims to design electronic module (e-module) oriented to the development of students’ chemical literacy on the solution colligative properties material. This research undergoes some stages including concept analysis, discourse analysis, storyboard design, design development, product packaging, validation, and feasibility test. Overall, this research undertakes three main stages, namely, Define (in the form of preliminary studies); Design (designing e-module); Develop (including validation and model trial). The concept presentation and visualization used in this e-module is oriented to chemical literacy skills. The presentation order carries aspects of scientific context, process, content, and attitude. Chemists and multi media experts have done the validation to test the initial quality of the products and give a feedback for the product improvement. The feasibility test results stated that the content presentation and display are valid and feasible to be used with the value of 85.77% and 87.94%. These values indicate that this e-module oriented to students’ chemical literacy skills for the solution colligative properties material is feasible to be used.

A cylindrical shell with an arbitrarily oriented crack

NASA Technical Reports Server (NTRS)

Yahsi, O. S.; Erdogan, F.

1983-01-01

The general problem of a shallow shell with constant curvatures is considered. It is assumed that the shell contains an arbitrarily oriented through crack and the material is specially orthotropic. The nonsymmetric problem is solved for arbitrary self equilibrating crack surface tractions, which, added to an appropriate solution for an uncracked shell, would give the result for a cracked shell under most general loading conditions. The problem is reduced to a system to five singular integral equations in a set of unknown functions representing relative displacements and rotations on the crack surfaces. The stress state around the crack tip is asymptotically analyzed and it is shown that the results are identical to those obtained from the two dimensional in plane and antiplane elasticity solutions. The numerical results are given for a cylindrical shell containing an arbitrarily oriented through crack. Some sample results showing the effect of the Poisson's ratio and the material orthotropy are also presented. Previously annunced in STAR as N83-16783

Effect of intrinsic zinc oxide coating on the properties of Al-doped zinc oxide nanorod arrays

NASA Astrophysics Data System (ADS)

Saidi, S. A.; Mamat, M. H.; Ismail, A. S.; Malek, M. F.; Yusoff, M. M.; Sin, N. D. Md.; Zoolfakar, A. S.; Khusaimi, Z.; Rusop, M.

2018-05-01

The aim of this study was to explore the influence of intrinsic zinc oxide (ZnO) coating fabricated by a simple immersion method. X-ray powder diffraction (XRD) analysis indicated that the Al-doped ZnO nanorod arrays films had a hexagonal wurtzite structure, similar to that of an intrinsic ZnO coating. Structural properties of the samples were characterised using field emission scanning electron microscopy (FESEM; JEOL JSM-7600F) and optical properties using X-ray diffraction (XRD). The XRD results showed that all films were crystallized under hexagonal wurtzite structure and presented a preferential orientation along the c-axis (002) was obtained. The XRD results showed that the intrinsic ZnO coating material had a strong orientation, whereas the ZnO was randomly oriented. Overall these results indicate that intrinsic ZnO coating are pontetial for the creation of functional materials such as barrier protection, optoelectronic devices, humidity sensor and ultraviolet photoconductive sensor.

Nondestructive testing based on scanning-from-heating approach: application to nonthrough defect detection and fiber orientation assessment

NASA Astrophysics Data System (ADS)

Belkacemi, Mohamed; Stolz, Christophe; Mathieu, Alexandre; Lemaitre, Guillaume; Massich, Joan; Aubreton, Olivier

2015-11-01

Today, industries ensure the quality of their manufactured products through computer vision techniques and nonconventional imaging. Three-dimensional (3-D) scanners and nondestructive testing (NDT) systems are commonly used independently for such applications. Furthermore, these approaches combined constitute hybrid systems, providing a 3-D reconstruction and NDT analysis. These systems, however, suffer from drawbacks such as errors during the data fusion and higher cost for manufacturers. In an attempt to solve these problems, a single active thermography system based on scanning-from-heating is proposed in this paper. In addition to 3-D digitization of the object, our contributions are twofold: (1) the nonthrough defect detection for a homogeneous metallic object and (2) fiber orientation assessment for a long fiber composite material. The experiments on steel and aluminum plates show that our method achieves the detection of nonthrough defects. Additionally, the estimation of the fiber orientation is evaluated on carbon-fiber composite material.

Highly oriented Bi-based thin films with zero resistance at 106 K

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

Kula, W.; Sobolewski, R.; Gorecka, J.

1991-03-01

This paper reports on fabrication and characterization of nearly single-phase superconducting Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} thin films. The films were dc magnetron sputtered from heavily Pb-doped (Pb/Bi molar ratios up to 1.25), sintered targets on unheated MgO, SrTiO{sub 3}, CaNdAlO{sub 4}, and SrLaAlO{sub 4} single crystals. For the films grown on the (100) oriented MgO substrate, less than 1 hour of annealing in air at 870{degrees} C was sufficient to obtain more than 90% of the 110-K-phase material, with highly c-axis oriented crystalline structure and zero resistivity at 106 K. The films fabricated on the other substrates alsomore » exhibited a narrow superconducting transition and were fully superconducting above 100 K, but they consisted of a mixed-phase material with a large percentage of the 80 K phase.« less

Generalizable Communications Skills Resource Directory.

ERIC Educational Resources Information Center

Greenan, James P.; And Others

This directory is designed to serve as a resource guide for vocational educators who need additional instructional material in the teaching of communications or vocationally oriented communications in their classes. The user guide explains the organization and use of the manual. The Communications Resource Materials section is divided into topic…

Building Spoken Language in the First Plane

ERIC Educational Resources Information Center

Bettmann, Joen

2016-01-01

Through a strong Montessori orientation to the parameters of spoken language, Joen Bettmann makes the case for "materializing" spoken knowledge using the stimulation of real objects and real situations that promote mature discussion around the sensorial aspect of the prepared environment. She lists specific materials in the classroom…

10 CFR 2.1003 - Availability of material.

Code of Federal Regulations, 2013 CFR

2013-01-01

... its license application for a geologic repository, the NRC shall make available no later than thirty... privilege in § 2.1006, graphic-oriented documentary material that includes raw data, computer runs, computer... discrepancies; (ii) Gauge, meter and computer settings; (iii) Probe locations; (iv) Logging intervals and rates...

10 CFR 2.1003 - Availability of material.

Code of Federal Regulations, 2011 CFR

2011-01-01

... months in advance of submitting its license application for a geologic repository, the NRC shall make... of privilege in § 2.1006, graphic-oriented documentary material that includes raw data, computer runs, computer programs and codes, field notes, laboratory notes, maps, diagrams and photographs, which have been...

10 CFR 2.1003 - Availability of material.

Code of Federal Regulations, 2012 CFR

2012-01-01

... months in advance of submitting its license application for a geologic repository, the NRC shall make... of privilege in § 2.1006, graphic-oriented documentary material that includes raw data, computer runs, computer programs and codes, field notes, laboratory notes, maps, diagrams and photographs, which have been...

10 CFR 2.1003 - Availability of material.

Code of Federal Regulations, 2014 CFR

2014-01-01

... its license application for a geologic repository, the NRC shall make available no later than thirty... privilege in § 2.1006, graphic-oriented documentary material that includes raw data, computer runs, computer... discrepancies; (ii) Gauge, meter and computer settings; (iii) Probe locations; (iv) Logging intervals and rates...

Pedestal Grinder.

ERIC Educational Resources Information Center

Engelbrecht, Nancy; And Others

These instructional materials provide an orientation to the pedestal grinder for use at the postsecondary level. The first of eight sections defines 14 important terms. The second section outlines 16 rules for safe use of the pedestal grinder. The third section covers grinding wheels for five different types of materials. The fourth section…

Criminal Justice Audiovisual Materials Directory.

ERIC Educational Resources Information Center

Law Enforcement Assistance Administration (Dept. of Justice), Washington, DC.

This source directory of audiovisual materials for the education, training, and orientation of those in the criminal justice field is divided into five parts covering the courts, police techniques and training, prevention, prisons and rehabilitation/correction, and public education. Each entry includes a brief description of the product, the time…

Grain Boundary Plane Orientation Fundamental Zones and Structure-Property Relationships

PubMed Central

Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

2015-01-01

Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to the strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries. PMID:26498715

Grain boundary plane orientation fundamental zones and structure-property relationships

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

Homer, Eric R.; Patala, Srikanth; Priedeman, Jonathan L.

2015-10-26

Grain boundary plane orientation is a profoundly important determinant of character in polycrystalline materials that is not well understood. This work demonstrates how boundary plane orientation fundamental zones, which capture the natural crystallographic symmetries of a grain boundary, can be used to establish structure-property relationships. Using the fundamental zone representation, trends in computed energy, excess volume at the grain boundary, and temperature-dependent mobility naturally emerge and show a strong dependence on the boundary plane orientation. Analysis of common misorientation axes even suggests broader trends of grain boundary energy as a function of misorientation angle and plane orientation. Due to themore » strong structure-property relationships that naturally emerge from this work, boundary plane fundamental zones are expected to simplify analysis of both computational and experimental data. This standardized representation has the potential to significantly accelerate research in the topologically complex and vast five-dimensional phase space of grain boundaries.« less

Constitutive Modeling of Nanotube/Polymer Composites with Various Nanotube Orientations

NASA Technical Reports Server (NTRS)

Odegard, Gregory M.; Gates, Thomas S.

2002-01-01

In this study, a technique has been proposed for developing constitutive models for polymer composite systems reinforced with single-walled carbon nanotubes (SWNT) with various orientations with respect to the bulk material coordinates. A nanotube, the local polymer adjacent to the nanotube, and the nanotube/polymer interface have been modeled as an equivalent-continuum fiber by using an equivalent-continuum modeling method. The equivalent-continuum fiber accounts for the local molecular structure and bonding information and serves as a means for incorporating micromechanical analyses for the prediction of bulk mechanical properties of SWNT/polymer composite. As an example, the proposed approach is used for the constitutive modeling of a SWNT/LaRC-SI (with a PmPV interface) composite system, with aligned nanotubes, three-dimensionally randomly oriented nanotubes, and nanotubes oriented with varying degrees of axisymmetry. It is shown that the Young s modulus is highly dependent on the SWNT orientation distribution.

Spatial confinement governs orientational order in patchy particles

NASA Astrophysics Data System (ADS)

Iwashita, Yasutaka; Kimura, Yasuyuki

2016-06-01

Orientational order in condensed matter plays a key role in determining material properties such as ferromagnetism, viscoelasticity or birefringence. We studied purely orientational ordering in closely-packed one-patch colloidal particles confined between flat substrates, where the particles can only rotate and are ordered via the sticky interaction between the patches. For the first time, we experimentally realized a rich variety of mesoscopic patterns through orientational ordering of colloids by controlling patch size and confinement thickness. The combination of experiment and numerical simulation reveals the decisive role of confinement: An ordered state(s) is selected from the (meta)stable options in bulk when it is commensurate with the system geometry and boundary conditions; otherwise, frustration induces a unique order. Our study offers a new means of systematic control over mesoscopic structures via orientational ordering in patchy particles. The system would also possess unique functionalities through the rotational response of the particles to external stimuli.

Superconducting magnetic coil

DOEpatents

Aized, Dawood; Schwall, Robert E.

1999-06-22

A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

Superconducting magnetic coil

DOEpatents

Aized, Dawood; Schwall, Robert E.

1996-06-11

A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.

Graphitization of Glassy Carbon after Compression at Room Temperature

NASA Astrophysics Data System (ADS)

Shiell, T. B.; McCulloch, D. G.; McKenzie, D. R.; Field, M. R.; Haberl, B.; Boehler, R.; Cook, B. A.; de Tomas, C.; Suarez-Martinez, I.; Marks, N. A.; Bradby, J. E.

2018-05-01

Glassy carbon is a technologically important material with isotropic properties that is nongraphitizing up to ˜3000 °C and displays complete or "superelastic" recovery from large compression. The pressure limit of these properties is not yet known. Here we use experiments and modeling to show permanent densification, and preferred orientation occurs in glassy carbon loaded to 45 GPa and above, where 45 GPa represents the limit to the superelastic and nongraphitizing properties of the material. The changes are explained by a transformation from its s p2 rich starting structure to a s p3 rich phase that reverts to fully s p2 bonded oriented graphite during pressure release.

1000 to 1200 K time-dependent compressive deformation of single-crystalline and polycrystalline B2 Ni-40Al

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Noebe, R. D.; Kumar, K. S.; Mannan, S. K.; Cullers, C. L.

1991-01-01

The 1000-K and 1200-K time-dependent deformation of 100-line-oriented and non-100-line-oriented single crystals of Ni-40Al (made by a modified Bridgman technique) was examined over a large range of strain rates (from 0.1 to 10 to the -7th per sec). The results were compared with those for polycrystalline Ni-40Al made by hot pressing XD synthesized powder. The results from measurements of slow-plastic-strain-rate properties of the two materials show that single crystals offer no strength advantage over polycrystalline material. Both forms were found to deform via a dislocation climb mechanism.

The effective magnetoelectric coefficients of polycrystalline Cr2O3 annealed in perpendicular electric and magnetic fields

NASA Astrophysics Data System (ADS)

Liu, Y. Y.; Xie, S. H.; Jin, G.; Li, J. Y.

2009-04-01

Magnetoelectric annealing is necessary to remove antiferromagnetic domains and induce macroscopic magnetoelectric effect in polycrystalline magnetoelectric materials, and in this paper, we study the effective magnetoelectric properties of perpendicularly annealed polycrystalline Cr2O3 using effective medium approximation. The effect of temperatures, grain aspect ratios, and two different types of orientation distribution function have been analyzed, and unusual material symmetry is observed when the orientation distribution function only depends on Euler angle ψ. Optimal grain aspect ratio and texture coefficient are also identified. The approach can be applied to analyze the microstructural field distribution and macroscopic properties of a wide range of magnetoelectric polycrystals.

Development of generalized 3-D braiding machines for composite preforms

NASA Technical Reports Server (NTRS)

Huey, Cecil O., Jr.; Farley, Gary L.

1993-01-01

The operating principles of two prototype braiding machines for the production of generalized braid patterns are described. Both processes afford previously unachievable control of the interlacing of fibers within a textile structure that make them especially amenable to the fabrication of textile preforms for composite materials. They enable independent control of the motion of the individual fibers being woven, thereby enabling the greatest possible freedom in controlling fiber orientation within a structure. This freedom enables the designer to prescribe local fiber orientation to better optimize material performance. The processes have been implemented on a very small scale but at a level that demonstrates their practicality and the soundness of the principles governing their operation.

Shock and Microstructural Characterization of the α-ω Phase Transition in Titanium Crystals

NASA Astrophysics Data System (ADS)

Morrow, Benjamin M.; Rigg, Paulo A.; Jones, David R.; Addessio, Francis L.; Trujillo, Carl P.; Saavedra, Ramon A.; Martinez, Daniel T.; Cerreta, Ellen K.

2017-12-01

A multicrystal comprised of a small number of large crystals of high-purity titanium and a [0001] oriented high-purity single crystal titanium sample were shock loaded using gas gun plate impact experiments. Tests were performed at stresses above the α {-}ω phase transition stress (for high-purity polycrystalline specimens) to observe the behavior of oriented crystals under similar conditions. Post-mortem characterization of the shocked microstructure was conducted on the single crystal sample to measure textures, and quantify phases and twinning. The apparent activation of plastic and transformation mechanisms was dependent upon crystal orientation. Specifically, the [0001] crystal showed a higher Hugoniot elastic limit than the [10\\bar{1}0] or [3\\bar{1}\\bar{4}4] orientations. The slope of velocity as a function of time was lower in the [0001] orientation than the other orientations during plastic deformation, indicating sluggish transformation kinetics for the α to ω phase transition for the [0001] oriented crystal. Microtexture measurements of a recovered [0001] oriented single crystal revealed the presence of retained ω phase after unloading, with orientations of the constituent phase fractions indicative of the forward α → ω transition, rather than the reverse ω → α transition, suggesting that the material never achieved a state of 100% ω phase.

Optimizing Street Canyon Orientation for Rajarhat Newtown, Kolkata, India

NASA Astrophysics Data System (ADS)

De, Bhaskar; Mukherjee, Mahua

2017-12-01

Air temperature in urban street canyons is increased due to the morphed urban geometry, increased surface area, decreased long wave radiation and evapo-transpiration, different thermo-physical properties of surface materials and anthropogenic heat which results in thermal discomfort. Outdoor thermal stress can be mitigated substantially by properly orienting the canyons. It is crucial for the urban planners and designers to orient street canyons optimally considering variable local climatic context. It is important especially for cities in warm humid climatic context as these cities receive higher insolation with higher relative humidity and low level macro wind flow. This paper examines influence of canyon orientation on outdoor thermal comfort and proposes the optimum canyon orientation for the Rajarhat Newtown, Kolkata - a city in warm humid climate zone. Different scenarios are generated with different orientations. Change in air temperature, wind speed, Mean Radiant Temperature (MRT) and Physiological Equivalent Temperature (PET) of different scenarios are compared to find out the optimum orientation by parametric simulation in ENVI_met. Analysing the simulation results it is observed that orientation angle between 30°-60° to north performs the best for the study area of the Rajarhat Newtown. The findings of this research will be helpful for the planners to orient the street canyons optimally for future development and extension of the Rajarhat Newtown, Kolkata.

Tunable transport property of oxygen ion in metal oxide thin film: Impact of electrolyte orientation on conductivity.

PubMed

Arunkumar, P; Ramaseshan, R; Dash, S; Babu, K Suresh

2017-06-14

Quest for efficient ion conducting electrolyte thin film operating at intermediate temperature (~600 °C) holds promise for the real-world utilization of solid oxide fuel cells. Here, we report the correlation between mixed as well as preferentially oriented samarium doped cerium oxide electrolyte films fabricated by varying the substrate temperatures (100, 300 and 500 °C) over anode/ quartz by electron beam physical vapor deposition. Pole figure analysis of films deposited at 300 °C demonstrated a preferential (111) orientation in out-off plane direction, while a mixed orientation was observed at 100 and 500 °C. As per extended structural zone model, the growth mechanism of film differs with surface mobility of adatom. Preferential orientation resulted in higher ionic conductivity than the films with mixed orientation, demonstrating the role of growth on electrochemical properties. The superior ionic conductivity upon preferential orientation arises from the effective reduction of anisotropic nature and grain boundary density in highly oriented thin films in out-of-plane direction, which facilitates the hopping of oxygen ion at a lower activation energy. This unique feature of growing an oriented electrolyte over the anode material opens a new approach to solving the grain boundary limitation and makes it as a promising solution for efficient power generation.

Three-dimensional full-field X-ray orientation microscopy

PubMed Central

Viganò, Nicola; Tanguy, Alexandre; Hallais, Simon; Dimanov, Alexandre; Bornert, Michel; Batenburg, Kees Joost; Ludwig, Wolfgang

2016-01-01

A previously introduced mathematical framework for full-field X-ray orientation microscopy is for the first time applied to experimental near-field diffraction data acquired from a polycrystalline sample. Grain by grain tomographic reconstructions using convex optimization and prior knowledge are carried out in a six-dimensional representation of position-orientation space, used for modelling the inverse problem of X-ray orientation imaging. From the 6D reconstruction output we derive 3D orientation maps, which are then assembled into a common sample volume. The obtained 3D orientation map is compared to an EBSD surface map and local misorientations, as well as remaining discrepancies in grain boundary positions are quantified. The new approach replaces the single orientation reconstruction scheme behind X-ray diffraction contrast tomography and extends the applicability of this diffraction imaging technique to material micro-structures exhibiting sub-grains and/or intra-granular orientation spreads of up to a few degrees. As demonstrated on textured sub-regions of the sample, the new framework can be extended to operate on experimental raw data, thereby bypassing the concept of orientation indexation based on diffraction spot peak positions. This new method enables fast, three-dimensional characterization with isotropic spatial resolution, suitable for time-lapse observations of grain microstructures evolving as a function of applied strain or temperature. PMID:26868303

A Novel Microcharacterization Technique in the Measurement of Strain and Orientation Gradient in Advanced Materials

NASA Technical Reports Server (NTRS)

Garmestai, H.; Harris, K.; Lourenco, L.

1997-01-01

Representation of morphology and evolution of the microstructure during processing and their relation to properties requires proper experimental techniques. Residual strains, lattice distortion, and texture (micro-texture) at the interface and the matrix of a layered structure or a functionally gradient material and their variation are among parameters important in materials characterization but hard to measure with present experimental techniques. Current techniques available to measure changes in interred material parameters (residual stress, micro-texture, microplasticity) produce results which are either qualitative or unreliable. This problem becomes even more complicated in the case of a temperature variation. These parameters affect many of the mechanical properties of advanced materials including stress-strain relation, ductility, creep, and fatigue. A review of some novel experimental techniques using recent advances in electron microscopy is presented here to measure internal stress, (micro)texture, interracial strength and (sub)grain formation and realignment. Two of these techniques are combined in the chamber of an Environmental Scanning Electron Microscope to measure strain and orientation gradients in advanced materials. These techniques which include Backscattered Kikuchi Diffractometry (BKD) and Microscopic Strain Field Analysis are used to characterize metallic and intermetallic matrix composites and superplastic materials. These techniques are compared with the more conventional x-ray diffraction and indentation techniques.

Liquid crystalline ordering and charge transport in semiconducting materials.

PubMed

Pisula, Wojciech; Zorn, Matthias; Chang, Ji Young; Müllen, Klaus; Zentel, Rudolf

2009-07-16

Organic semiconducting materials offer the advantage of solution processability into flexible films. In most cases, their drawback is based on their low charge carrier mobility, which is directly related to the packing of the molecules both on local (amorphous versus crystalline) and on macroscopic (grain boundaries) length scales. Liquid crystalline ordering offers the possibility of circumventing this problem. An advanced concept comprises: i) the application of materials with different liquid crystalline phases, ii) the orientation of a low viscosity high temperature phase, and, iii) the transfer of the macroscopic orientation during cooling to a highly ordered (at best, crystalline-like) phase at room temperature. At the same time, the desired orientation for the application (OLED or field-effect transistor) can be obtained. This review presents the use of molecules with discotic, calamitic and sanidic phases and discusses the sensitivity of the phases with regard to defects depending on the dimensionality of the ordered structure (columns: 1D, smectic layers and sanidic phases: 2D). It presents ways to systematically improve charge carrier mobility by proper variation of the electronic and steric (packing) structure of the constituting molecules and to reach charge carrier mobilities that are close to and comparable to amorphous silicon, with values of 0.1 to 0.7 cm(2)  · V(-1)  · s(-1) . In this context, the significance of cross-linking to stabilize the orientation and liquid crystalline behavior of inorganic/organic hybrids is also discussed. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High-Strength Composite Fabric Tested at Structural Benchmark Test Facility

NASA Technical Reports Server (NTRS)

Krause, David L.

2002-01-01

Large sheets of ultrahigh strength fabric were put to the test at NASA Glenn Research Center's Structural Benchmark Test Facility. The material was stretched like a snare drum head until the last ounce of strength was reached, when it burst with a cacophonous release of tension. Along the way, the 3-ft square samples were also pulled, warped, tweaked, pinched, and yanked to predict the material's physical reactions to the many loads that it will experience during its proposed use. The material tested was a unique multi-ply composite fabric, reinforced with fibers that had a tensile strength eight times that of common carbon steel. The fiber plies were oriented at 0 and 90 to provide great membrane stiffness, as well as oriented at 45 to provide an unusually high resistance to shear distortion. The fabric's heritage is in astronaut space suits and other NASA programs.

Comparison of Ductile-to-Brittle Transition Behavior in Two Similar Ferritic Oxide Dispersion Strengthened Alloys.

PubMed

Chao, Jesus; Rementeria, Rosalia; Aranda, Maria; Capdevila, Carlos; Gonzalez-Carrasco, Jose Luis

2016-07-29

The ductile-to-brittle transition (DBT) behavior of two similar Fe-Cr-Al oxide dispersion strengthened (ODS) stainless steels was analyzed following the Cottrell-Petch model. Both alloys were manufactured by mechanical alloying (MA) but by different forming routes. One was manufactured as hot rolled tube, and the other in the form of hot extruded bar. The two hot forming routes considered do not significantly influence the microstructure, but cause differences in the texture and the distribution of oxide particles. These have little influence on tensile properties; however, the DBT temperature and the upper shelf energy (USE) are significantly affected because of delamination orientation with regard to the notch plane. Whereas in hot rolled material the delaminations are parallel to the rolling surface, in the hot extruded material, they are randomly oriented because the material is transversally isotropic.

Lattice-cell orientation disorder in complex spinel oxides

DOE PAGES

Chen, Yan; Cheng, Yongqiang; Li, Juchuan; ...

2016-11-07

Transition metal (TM) substitution has been widely applied to change complex oxides crystal structures to create high energy density electrodes materials in high performance rechargeable lithium-ion batteries. The complex local structure in the oxides imparted by the TM arrangement often impacts their electrochemical behaviors by influencing the diffusion and intercalation of lithium. Here, a major discrepancy is demonstrated between the global and local structures of the promising high energy density and high voltage LiNi 0.5Mn 1.5O 4 spinel cathode material that contradicts the existing structural models. A new single-phase lattice-cell orientation disorder model is proposed as the mechanism for themore » local ordering that explains how the inhomogeneous local distortions and the coherent connection give rise to the global structure in the complex oxide. As a result, the single-phase model is consistent with the electrochemical behavior observation of the materials.« less

Comparison of Ductile-to-Brittle Transition Behavior in Two Similar Ferritic Oxide Dispersion Strengthened Alloys

PubMed Central

Chao, Jesus; Rementeria, Rosalia; Aranda, Maria; Capdevila, Carlos; Gonzalez-Carrasco, Jose Luis

2016-01-01

The ductile-to-brittle transition (DBT) behavior of two similar Fe-Cr-Al oxide dispersion strengthened (ODS) stainless steels was analyzed following the Cottrell–Petch model. Both alloys were manufactured by mechanical alloying (MA) but by different forming routes. One was manufactured as hot rolled tube, and the other in the form of hot extruded bar. The two hot forming routes considered do not significantly influence the microstructure, but cause differences in the texture and the distribution of oxide particles. These have little influence on tensile properties; however, the DBT temperature and the upper shelf energy (USE) are significantly affected because of delamination orientation with regard to the notch plane. Whereas in hot rolled material the delaminations are parallel to the rolling surface, in the hot extruded material, they are randomly oriented because the material is transversally isotropic. PMID:28773764

Comparison of thermal insulation performance of fibrous materials for the advanced space suit.

PubMed

Paul, Heather L; Diller, Kenneth R

2003-10-01

The current multi-layer insulation used in the extravehicular mobility unit (EMU) will not be effective in the atmosphere of Mars due to the presence of interstitial gases. Alternative thermal insulation means have been subjected to preliminary evaluation by NASA to attempt to identify a material that will meet the target conductivity of 0.005 W/m-K. This study analyzes numerically the thermal conductivity performance for three of these candidate insulating fiber materials in terms of various denier (size), interstitial void fractions, interstitial void media, and orientations to the applied temperature gradient to evaluate their applicability for the new Mars suit insulation. The results demonstrate that the best conductive insulation is achieved for a high-void-fraction configuration with a grooved fiber cross section, aerogel void medium, and the fibers oriented normal to the heat flux vector. However, this configuration still exceeds the target thermal conductivity by a factor of 1.5.

Experimental Study on the Anisotropic Stress-Strain Behavior of Polycrystalline Ni-Mn-Ga in Directional Solidification

NASA Astrophysics Data System (ADS)

Teng, Yao; Shi, Tao; Zhu, Yuping; Li, Zongbin; Deng, Tao; Bai, Guonan

2016-03-01

A polycrystalline Ni-Mn-Ga ferromagnetic shape memory alloy produced by directional solidification is the subject of this research paper. The compressive stress-strain curves of the material for different cutting angles to the solidification direction are tested. The martensite Young's modulus, macroscopic reorientation strain, and phase transition critical stress are analyzed experimentally. The results show that mechanical behaviors in the loading-unloading cycle of the material present nonlinear and anisotropic characteristics, which are all closely related to the material's orientation to the solidification direction. The martensite Young's modulus, macroscopic reorientation strain, and phase transition critical stress achieve maximum values in the solidification direction. A 50° orientation to the solidification direction is the cut-off direction of the mechanical properties, where the martensite Young's modulus and reorientation start critical stress reach minimum values. The present study is expected to provide sound guidance for practical applications.

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

Serrano-Sánchez, F.; Gharsallah, M.; Nemes, N. M.

SnSe has been prepared by arc-melting, as mechanically robust pellets, consisting of highly oriented polycrystals. This material has been characterized by neutron powder diffraction (NPD), scanning electron microscopy, and transport measurements. A microscopic analysis from NPD data demonstrates a quite perfect stoichiometry SnSe{sub 0.98(2)} and a fair amount of anharmonicity of the chemical bonds. The Seebeck coefficient reaches a record maximum value of 668 μV K{sup −1} at 380 K; simultaneously, this highly oriented sample exhibits an extremely low thermal conductivity lower than 0.1 W m{sup −1} K{sup −1} around room temperature, which are two of the main ingredients of good thermoelectric materials. Thesemore » excellent features exceed the reported values for this semiconducting compound in single crystalline form in the moderate-temperatures region and highlight its possibilities as a potential thermoelectric material.« less

Optimization of Ferroelectric Ceramics by Design at the Microstructure Level

NASA Astrophysics Data System (ADS)

Jayachandran, K. P.; Guedes, J. M.; Rodrigues, H. C.

2010-05-01

Ferroelectric materials show remarkable physical behaviors that make them essential for many devices and have been extensively studied for their applications of nonvolatile random access memory (NvRAM) and high-speed random access memories. Although ferroelectric ceramics (polycrystals) present ease in manufacture and in compositional modifications and represent the widest application area of materials, computational and theoretical studies are sparse owing to many reasons including the large number of constituent atoms. Macroscopic properties of ferroelectric polycrystals are dominated by the inhomogeneities at the crystallographic domain/grain level. Orientation of grains/domains is critical to the electromechanical response of the single crystalline and polycrystalline materials. Polycrystalline materials have the potential of exhibiting better performance at a macroscopic scale by design of the domain/grain configuration at the domain-size scale. This suggests that piezoelectric properties can be optimized by a proper choice of the parameters which control the distribution of grain orientations. Nevertheless, this choice is complicated and it is impossible to analyze all possible combinations of the distribution parameters or the angles themselves. Hence we have implemented the stochastic optimization technique of simulated annealing combined with the homogenization for the optimization problem. The mathematical homogenization theory of a piezoelectric medium is implemented in the finite element method (FEM) by solving the coupled equilibrium electrical and mechanical fields. This implementation enables the study of the dependence of the macroscopic electromechanical properties of a typical crystalline and polycrystalline ferroelectric ceramic on the grain orientation.

In-plane x-ray diffraction for characterization of monolayer and few-layer transition metal dichalcogenide films

NASA Astrophysics Data System (ADS)

Chubarov, Mikhail; Choudhury, Tanushree H.; Zhang, Xiaotian; Redwing, Joan M.

2018-02-01

There is significant interest in the growth of single crystal monolayer and few-layer films of transition metal dichalcogenides (TMD) and other 2D materials for scientific exploration and potential applications in optics, electronics, sensing, catalysis and others. The characterization of these materials is crucial in determining the properties and hence the applications. The ultra-thin nature of 2D layers presents a challenge to the use of x-ray diffraction (XRD) analysis with conventional Bragg-Brentano geometry in analyzing the crystallinity and epitaxial orientation of 2D films. To circumvent this problem, we demonstrate the use of in-plane XRD employing lab scale equipment which uses a standard Cu x-ray tube for the analysis of the crystallinity of TMD monolayer and few-layer films. The applicability of this technique is demonstrated in several examples for WSe2 and WS2 films grown by chemical vapor deposition on single crystal substrates. In-plane XRD was used to determine the epitaxial relation of WSe2 grown on c-plane sapphire and on SiC with an epitaxial graphene interlayer. The evolution of the crystal structure orientation of WS2 films on sapphire as a function of growth temperature was also examined. Finally, the epitaxial relation of a WS2/WSe2 vertical heterostructure deposited on sapphire substrate was determined. We observed that WSe2 grows epitaxially on both substrates employed in this work under all conditions studied while WS2 exhibits various preferred orientations on sapphire substrate which are temperature dependent. In contrast to the sapphire substrate, WS2 deposited on WSe2 exhibits only one preferred orientation which may provide a route to better control the orientation and crystal quality of WS2. In the case of epitaxial graphene on SiC, no graphene-related peaks were observed in in-plane XRD while its presence was confirmed using Raman spectroscopy. This demonstrates the limitation of the in-plane XRD technique for characterizing low electron density materials.

Get Your Bearings

ERIC Educational Resources Information Center

Teaching Pre K-8, 2004

2004-01-01

This article describes an outdoor activity known as orienteering, the practice of using a map and a compass to find points in a landscape. Downloadable materials, courtesy of The Roger Tory Peterson Institute, can be found on www.TeachingK-8.com. These materials include instructions for the activity and reproducible illustrations of seven basic…

Development of Employable Skills in Vocational Education by the Utilization of Instructional Materials

ERIC Educational Resources Information Center

Owoh, Titus M.

2016-01-01

The acquisition of practical and applied skills as well as the basic scientific knowledge that would facilitate efficient occupational training requires good manipulation of skills oriented instructional facilities in a conducive learning situation. Thus, the provision and effective utilization of functional instructional materials are essential…

Nondestructive Testing Magnetic Particle RQA/M1-5330.11.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

As one in the series of programmed instruction handbooks, prepared by the U. S. space program, home study material is presented in this volume concerning familiarization and orientation on magnetic particle properties. The subject is presented under the following headings: Magnetism, Producing a Magnetic Field, Magnetizing Currents, Materials and…

Sex Fairness in Career Guidance: A Learning Kit.

ERIC Educational Resources Information Center

Stebbins, Linda B.; And Others

This learning kit presents self-administered curriculum materials which can be used by counselors and counselor educators to aid in the elimination of sex-role stereotyping and sex bias in career choice. Curriculum materials are organized into four chapters: (1) "Orientation to Sex Fairness" introduces the dual role system, discusses traditional…

Effect of chlorine dioxide gas on physical, thermal, mechanical, and barrier properties of p[olymeric packaging materials

USDA-ARS?s Scientific Manuscript database

In the first part of our study we determined permeability, diffusion, and solubility coefficients of gaseous chlorine dioxide (ClO2) through the following packaging material: biaxial-oriented polypropylene (BOPP); polyethylene terephthalate (PET); poly lactic acid (PLA); multilayer structure of ethy...

Structural Health Monitoring of Composite Materials Using Distributed Fiber Bragg Sensors

NASA Technical Reports Server (NTRS)

Grant, Joseph; Kual, Raj; Taylor, Scott; Jackson, Kurt V.; Myers, George; Wang, Y.; Sharma, A.; Burdine, Robert (Technical Monitor)

2002-01-01

Health monitoring of polymer matrix composite materials using fiber optic Bragg grating (FBG) sensors is accomplished using a tunable IR (infrared) laser via transmission mode. Results are presented from experiments of composite structures with FBG's embedded at various orientations, and surface measurements of various cryogenic composite vessels.

Handling Vagueness as an Intelligent Component of a Materials Information System.

ERIC Educational Resources Information Center

Schudnagis, Monika; Womser-Hacker, Christa

1996-01-01

Discusses vagueness as a problem of materials information system development in the context of information retrieval within the paradigm of information science. Presents a prototype which combines an object-oriented graphical user interface with natural language feedback and correction functionality, as well as intelligent components for graphical…

49 CFR 178.507 - Standards for plywood drums.

Code of Federal Regulations, 2010 CFR

2010-10-01

... PACKAGINGS Non-bulk Performance-Oriented Packaging Standards § 178.507 Standards for plywood drums. (a) The... effectiveness of the drum for the purpose intended. A material other than plywood, of at least equivalent..., lids must be lined with kraft paper or some other equivalent material which must be securely fastened...

MIT Orients Course Materials Online to K-12

ERIC Educational Resources Information Center

Cavanagh, Sean

2008-01-01

Many science and mathematics educators across the country are taking advantage of a Web site created by the Massachusetts Institute of Technology (MIT), the famed research university located in Cambridge, Massachusetts, which offers free video, audio, and print lectures and course material taken straight from the school's classes. Those resources…

Criminal Justice Audiovisual Materials Directory.

ERIC Educational Resources Information Center

Law Enforcement Assistance Administration (Dept. of Justice), Washington, DC.

This is the third edition of a source directory of audiovisual materials for the education, training, and orientation of those in the criminal justice field. It is divided into five parts covering the courts, police techniques and training, prevention, prisons and rehabilitation/correction, and public education. Each entry includes a brief…

Multiscale finite element modeling of sheet molding compound (SMC) composite structure based on stochastic mesostructure reconstruction

DOE PAGES

Chen, Zhangxing; Huang, Tianyu; Shao, Yimin; ...

2018-03-15

Predicting the mechanical behavior of the chopped carbon fiber Sheet Molding Compound (SMC) due to spatial variations in local material properties is critical for the structural performance analysis but is computationally challenging. Such spatial variations are induced by the material flow in the compression molding process. In this work, a new multiscale SMC modeling framework and the associated computational techniques are developed to provide accurate and efficient predictions of SMC mechanical performance. The proposed multiscale modeling framework contains three modules. First, a stochastic algorithm for 3D chip-packing reconstruction is developed to efficiently generate the SMC mesoscale Representative Volume Element (RVE)more » model for Finite Element Analysis (FEA). A new fiber orientation tensor recovery function is embedded in the reconstruction algorithm to match reconstructions with the target characteristics of fiber orientation distribution. Second, a metamodeling module is established to improve the computational efficiency by creating the surrogates of mesoscale analyses. Third, the macroscale behaviors are predicted by an efficient multiscale model, in which the spatially varying material properties are obtained based on the local fiber orientation tensors. Our approach is further validated through experiments at both meso- and macro-scales, such as tensile tests assisted by Digital Image Correlation (DIC) and mesostructure imaging.« less

Structural characteristics of liquid nitromethane at the nanoscale confinement in carbon nanotubes.

PubMed

Liu, Yingzhe; Lai, Weipeng; Yu, Tao; Ge, Zhongxue; Kang, Ying

2014-10-01

The stability of energetic materials confined in the carbon nanotubes can be improved at ambient pressure and room temperature, leading to potential energy storage and controlled energy release. However, the microscopic structure of confined energetic materials and the role played by the confinement size are still fragmentary. In this study, molecular dynamics simulations have been performed to explore the structural characteristics of liquid nitromethane (NM), one of the simplest energetic materials, confined in a series of armchair single-walled carbon nanotubes (SWNTs) changing from (5,5) to (16,16) at ambient conditions. The simulation results show that the size-dependent ordered structures of NM with preferred orientations are formed inside the tubular cavities driven by the van der Waals attractions between NM and SWNT together with the dipole-dipole interactions of NM, giving rise to a higher local mass density than that of bulk NM. The NM dipoles prefer to align parallel along the SWNT axis in an end-to-end fashion inside all the nanotubes except the (7,7) SWNT where a unique staggered orientation of NM dipoles perpendicular to the SWNT axis is observed. As the SWNT radius increases, the structural arrangements and dipole orientations of NM become disordered as a result of the weakening of van der Waals interactions between NM and SWNT.

c-axis preferential orientation of hydroxyapatite accounts for the high wear resistance of the teeth of black carp (Mylopharyngodon piceus)

PubMed Central

Fu, Jimin; He, Chong; Xia, Biao; Li, Yan; Feng, Qiong; Yin, Qifang; Shi, Xinghua; Feng, Xue; Wang, Hongtao; Yao, Haimin

2016-01-01

Biological armors such as mollusk shells have long been recognized and studied for their values in inspiring novel designs of engineering materials with higher toughness and strength. However, no material is invincible and biological armors also have their rivals. In this paper, our attention is focused on the teeth of black carp (Mylopharyngodon piceus) which is a predator of shelled mollusks like snails and mussels. Nanoscratching test on the enameloid, the outermost layer of the teeth, indicates that the natural occlusal surface (OS) has much higher wear resistance compared to the other sections. Subsequent X-ray diffraction analysis reveals that the hydroxyapatite (HAp) crystallites in the vicinity of OS possess c-axis preferential orientation. The superior wear resistance of black carp teeth is attributed to the c-axis preferential orientation of HAp near the OS since the (001) surface of HAp crystal, which is perpendicular to the c-axis, exhibits much better wear resistance compared to the other surfaces as demonstrated by the molecular dynamics simulation. Our results not only shed light on the origin of the good wear resistance exhibited by the black carp teeth but are of great value to the design of engineering materials with better abrasion resistance. PMID:27001150

Multiscale finite element modeling of sheet molding compound (SMC) composite structure based on stochastic mesostructure reconstruction

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

Chen, Zhangxing; Huang, Tianyu; Shao, Yimin

Predicting the mechanical behavior of the chopped carbon fiber Sheet Molding Compound (SMC) due to spatial variations in local material properties is critical for the structural performance analysis but is computationally challenging. Such spatial variations are induced by the material flow in the compression molding process. In this work, a new multiscale SMC modeling framework and the associated computational techniques are developed to provide accurate and efficient predictions of SMC mechanical performance. The proposed multiscale modeling framework contains three modules. First, a stochastic algorithm for 3D chip-packing reconstruction is developed to efficiently generate the SMC mesoscale Representative Volume Element (RVE)more » model for Finite Element Analysis (FEA). A new fiber orientation tensor recovery function is embedded in the reconstruction algorithm to match reconstructions with the target characteristics of fiber orientation distribution. Second, a metamodeling module is established to improve the computational efficiency by creating the surrogates of mesoscale analyses. Third, the macroscale behaviors are predicted by an efficient multiscale model, in which the spatially varying material properties are obtained based on the local fiber orientation tensors. Our approach is further validated through experiments at both meso- and macro-scales, such as tensile tests assisted by Digital Image Correlation (DIC) and mesostructure imaging.« less

Non-destructive mapping of grain orientations in 3D by laboratory X-ray microscopy

PubMed Central

McDonald, S. A.; Reischig, P.; Holzner, C.; Lauridsen, E. M.; Withers, P. J.; Merkle, A. P.; Feser, M.

2015-01-01

The ability to characterise crystallographic microstructure, non-destructively and in three-dimensions, is a powerful tool for understanding many aspects related to damage and deformation mechanisms in polycrystalline materials. To this end, the technique of X-ray diffraction contrast tomography (DCT) using monochromatic synchrotron and polychromatic laboratory X-ray sources has been shown to be capable of mapping crystal grains and their orientations non-destructively in 3D. Here we describe a novel laboratory-based X-ray DCT modality (LabDCT), enabling the wider accessibility of the DCT technique for routine use and in-depth studies of, for example, temporal changes in crystallographic grain structure non-destructively over time through ‘4D’ in situ time-lapse studies. The capability of the technique is demonstrated by studying a titanium alloy (Ti-β21S) sample. In the current implementation the smallest grains that can be reliably detected are around 40 μm. The individual grain locations and orientations are reconstructed using the LabDCT method and the results are validated against independent measurements from phase contrast tomography and electron backscatter diffraction respectively. Application of the technique promises to provide important insights related to the roles of recrystallization and grain growth on materials properties as well as supporting 3D polycrystalline modelling of materials performance. PMID:26494523

Horizontal and vertical integration of academic disciplines in the medical school curriculum.

PubMed

Vidic, Branislav; Weitlauf, Harry M

2002-05-01

A rapid expansion of new scientific information and the introduction of new technology in operative and diagnostic medicine has marked the last several decades. Medical educators, because of and parallel to these developments, initiated a search for a more effective system of presenting core material to medical students. The new educational trends, although varying somewhat from one institution to another, concentrated on the following pedagogical shifts: 1) expansion of conceptual presentation of material at the expense of detail-oriented education; 2) amplification of an integrated approach, as opposed to subject-oriented instruction; 3) scheduling of elective courses to compliment required courses in the curriculum; and 4) institution of small group instruction (i.e., problem-based learning) to actively involve students in the educational process and to develop deductive reasoning based on clinical cases. The future pedagogical system in medical schools will most likely be a combination of "classical" presentation of material combined with concept-oriented, subject-integrated and small group instruction based on either hypothetical or real clinical cases. It is imperative for the success of the new curriculum, however, that certain criteria are satisfied: 1) reorganize basic science departments to determine course ownership; 2) establish a reward system for teaching faculty; and 3) establish new course objectives. Copyright 2002 Wiley-Liss, Inc.

Non-destructive mapping of grain orientations in 3D by laboratory X-ray microscopy

NASA Astrophysics Data System (ADS)

McDonald, S. A.; Reischig, P.; Holzner, C.; Lauridsen, E. M.; Withers, P. J.; Merkle, A. P.; Feser, M.

2015-10-01

The ability to characterise crystallographic microstructure, non-destructively and in three-dimensions, is a powerful tool for understanding many aspects related to damage and deformation mechanisms in polycrystalline materials. To this end, the technique of X-ray diffraction contrast tomography (DCT) using monochromatic synchrotron and polychromatic laboratory X-ray sources has been shown to be capable of mapping crystal grains and their orientations non-destructively in 3D. Here we describe a novel laboratory-based X-ray DCT modality (LabDCT), enabling the wider accessibility of the DCT technique for routine use and in-depth studies of, for example, temporal changes in crystallographic grain structure non-destructively over time through ‘4D’ in situ time-lapse studies. The capability of the technique is demonstrated by studying a titanium alloy (Ti-β21S) sample. In the current implementation the smallest grains that can be reliably detected are around 40 μm. The individual grain locations and orientations are reconstructed using the LabDCT method and the results are validated against independent measurements from phase contrast tomography and electron backscatter diffraction respectively. Application of the technique promises to provide important insights related to the roles of recrystallization and grain growth on materials properties as well as supporting 3D polycrystalline modelling of materials performance.

Non-destructive mapping of grain orientations in 3D by laboratory X-ray microscopy.

PubMed

McDonald, S A; Reischig, P; Holzner, C; Lauridsen, E M; Withers, P J; Merkle, A P; Feser, M

2015-10-23

The ability to characterise crystallographic microstructure, non-destructively and in three-dimensions, is a powerful tool for understanding many aspects related to damage and deformation mechanisms in polycrystalline materials. To this end, the technique of X-ray diffraction contrast tomography (DCT) using monochromatic synchrotron and polychromatic laboratory X-ray sources has been shown to be capable of mapping crystal grains and their orientations non-destructively in 3D. Here we describe a novel laboratory-based X-ray DCT modality (LabDCT), enabling the wider accessibility of the DCT technique for routine use and in-depth studies of, for example, temporal changes in crystallographic grain structure non-destructively over time through '4D' in situ time-lapse studies. The capability of the technique is demonstrated by studying a titanium alloy (Ti-β21S) sample. In the current implementation the smallest grains that can be reliably detected are around 40 μm. The individual grain locations and orientations are reconstructed using the LabDCT method and the results are validated against independent measurements from phase contrast tomography and electron backscatter diffraction respectively. Application of the technique promises to provide important insights related to the roles of recrystallization and grain growth on materials properties as well as supporting 3D polycrystalline modelling of materials performance.

Field-Induced Texturing of Ceramic Materials for Unparalleled Properties

DTIC Science & Technology

2017-03-01

research for materials-by- design and advanced processing. Invited talk; 17th International Conference on Experimental Mechanics; 2016 Jul; Rhodes...material that could potentially be textured despite its diamagnetic nature. Predictive DFT modeling and experimental testing methods were designed ...presented at the Mater Science Forum; 2007 (unpublished). 71. Sugiyama T, Tahashi M, Sassa K, Asai S. The control of crystal orientation in non -magnetic

Investigation of the shear response and geometrically necessary dislocation densities in shear localization in high-purity titanium

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

Zhu, Chaoyi; Livescu, Veronica; Harrington, Tyler

The influence of microstructural anisotropy on shear response of high-purity titanium was studied using the compact forced-simple-shear specimen (CFSS) loaded under quasi-static loading conditions. Post-mortem characterization reveals significant difference in shear response of different directions in the same material due to material crystallographic texture anisotropy. Shear bands are narrower in specimens in which the shear zone is aligned along the direction with a strong {0001} basal texture. Twinning was identified as an active mechanism to accommodate strains in the shear region in both orientations. This paper confirms the applicability of the CFSS design for the investigation of differences in themore » shear response of materials as a function of process-induced crystallographic texture. A detailed, systematic approach to quantifying shear band evolution by evaluating geometrically necessary dislocations (GND) associated with crystallographic anisotropy is presented. Finally, the results show that: i) line average GND density profiles, for Ti samples that possess a uniform equiaxed-grain structure, but with strong crystallographic anisotropy, exhibit significant differences in GND density close to the shear band center; ii) GND profiles decrease steadily away from the shear band as the plastic strain diminishes, in agreement with Ashby's theory of work hardening, where the higher GND density in the through-thickness (TT) orientation is a result of restricted < a > type slip in the shear band compared with in-plane (IP) samples; iii) the anisotropy in deformation response is derived from initial crystallographic texture of the materials, where GND density of < a > GNDs are higher adjacent to the shear band in the through-thickness sample oriented away from easy slip, but the density of < c+a > type GNDs are very similar in these two samples; and iv) the increase in grain average GND density was determined to have strong correlation to an increase in the Euler Φ angle of the grain average orientation, indicating an increased misorientation angle evolution.« less

Investigation of the shear response and geometrically necessary dislocation densities in shear localization in high-purity titanium

DOE PAGES

Zhu, Chaoyi; Livescu, Veronica; Harrington, Tyler; ...

2017-03-31

The influence of microstructural anisotropy on shear response of high-purity titanium was studied using the compact forced-simple-shear specimen (CFSS) loaded under quasi-static loading conditions. Post-mortem characterization reveals significant difference in shear response of different directions in the same material due to material crystallographic texture anisotropy. Shear bands are narrower in specimens in which the shear zone is aligned along the direction with a strong {0001} basal texture. Twinning was identified as an active mechanism to accommodate strains in the shear region in both orientations. This paper confirms the applicability of the CFSS design for the investigation of differences in themore » shear response of materials as a function of process-induced crystallographic texture. A detailed, systematic approach to quantifying shear band evolution by evaluating geometrically necessary dislocations (GND) associated with crystallographic anisotropy is presented. Finally, the results show that: i) line average GND density profiles, for Ti samples that possess a uniform equiaxed-grain structure, but with strong crystallographic anisotropy, exhibit significant differences in GND density close to the shear band center; ii) GND profiles decrease steadily away from the shear band as the plastic strain diminishes, in agreement with Ashby's theory of work hardening, where the higher GND density in the through-thickness (TT) orientation is a result of restricted < a > type slip in the shear band compared with in-plane (IP) samples; iii) the anisotropy in deformation response is derived from initial crystallographic texture of the materials, where GND density of < a > GNDs are higher adjacent to the shear band in the through-thickness sample oriented away from easy slip, but the density of < c+a > type GNDs are very similar in these two samples; and iv) the increase in grain average GND density was determined to have strong correlation to an increase in the Euler Φ angle of the grain average orientation, indicating an increased misorientation angle evolution.« less

Control of Heat and Charge Transport in Nanostructured Hybrid Materials

DTIC Science & Technology

2015-07-21

measurements in our groups have yielded device ZT values of 0.4 on thermoelectric modules consisting of vertically oriented silicon nanowires . This is... nanowires with aspect ratio’s exceeding 10,000. Temperature differences as high as 800 °C are achievable for both types. The bulk nanostructured...thermal conductivity of the silicon nanostructures. Specifically, experiments on an array of 20 nm diameter vertically oriented silicon nanowires have

COMETS Profiles. Career Oriented Modules to Explore Topics in Science. 24 Biographical Sketches of Women in Science Careers plus Accompanying Language Arts Activities.

ERIC Educational Resources Information Center

Noyce, Ruth, Ed.

Twenty-four biographical sketches of women in scientific professions are included in this COMETS Profiles package. Each biography relates to a science topic dealt with in one of the instructional modules of COMETS Science (Career Oriented Modules to Explore Topics in Science). The purpose of these materials is to demonstrate to early adolescents…

Performance oriented packaging testing of nine Mk 3 Mod 0 signal containers in PPP-B-621 wood box for packing group II solid hazardous materials. Final report

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

Libbert, K.J.

1992-10-01

A PPP-B-621 wood box containing nine Mk 3 Mod 0 Signal containers was tested for conformance to Performance Oriented Packaging criteria established by Code of Federal Regulations Title 49 CFR. The container was tested with a gross weight of 123.3 pounds (56 kilograms) and met all requirements.

Active Materials for Photonic Systems (AMPS)

DTIC Science & Technology

1998-04-13

titanium isopropoxide were used as metalorganic precursors. The PZT films grown on the (101) oriented Ru02 electrode layers are highly (001) oriented...fabrication it was noted mat adhesion loss occurred at the platinum/ titanium interface. This loss occurred during stripping of the photoresist layer used to...reveal that the titanium was present as titanium dioxide rather than as the original metal. This indicated that oxygen had diffused through the platinum

Shock wave-induced phase transition in RDX single crystals.

PubMed

Patterson, James E; Dreger, Zbigniew A; Gupta, Yogendra M

2007-09-20

The real-time, molecular-level response of oriented single crystals of hexahydro-1,3,5-trinitro-s-triazine (RDX) to shock compression was examined using Raman spectroscopy. Single crystals of [111], [210], or [100] orientation were shocked under stepwise loading to peak stresses from 3.0 to 5.5 GPa. Two types of measurements were performed: (i) high-resolution Raman spectroscopy to probe the material at peak stress and (ii) time-resolved Raman spectroscopy to monitor the evolution of molecular changes as the shock wave reverberated through the material. The frequency shift of the CH stretching modes under shock loading appeared to be similar for all three crystal orientations below 3.5 GPa. Significant spectral changes were observed in crystals shocked above 4.5 GPa. These changes were similar to those observed in static pressure measurements, indicating the occurrence of the alpha-gamma phase transition in shocked RDX crystals. No apparent orientation dependence in the molecular response of RDX to shock compression up to 5.5 GPa was observed. The phase transition had an incubation time of approximately 100 ns when RDX was shocked to 5.5 GPa peak stress. The observation of the alpha-gamma phase transition under shock wave loading is briefly discussed in connection with the onset of chemical decomposition in shocked RDX.

Fabrication of Ti substrate grain dependent C/TiO2 composites through carbothermal treatment of anodic TiO2.

PubMed

Rüdiger, Celine; Favaro, Marco; Valero-Vidal, Carlos; Calvillo, Laura; Bozzolo, Nathalie; Jacomet, Suzanne; Hejny, Clivia; Gregoratti, Luca; Amati, Matteo; Agnoli, Stefano; Granozzi, Gaetano; Kunze-Liebhäuser, Julia

2016-04-07

Composite materials of titania and graphitic carbon, and their optimized synthesis are highly interesting for application in sustainable energy conversion and storage. We report on planar C/TiO2 composite films that are prepared on a polycrystalline titanium substrate by carbothermal treatment of compact anodic TiO2 with acetylene. This thin film material allows for the study of functional properties of C/TiO2 as a function of chemical composition and structure. The chemical and structural properties of the composite on top of individual Ti substrate grains are examined by scanning photoelectron microscopy and micro-Raman spectroscopy. Through comparison of these data with electron backscatter diffraction, it is found that the amount of generated carbon and the grade of anodic film crystallinity correlate with the crystallographic orientation of the Ti substrate grains. On top of Ti grains with ∼(0001) orientations the anodic TiO2 exhibits the highest grade of crystallinity, and the composite contains the highest fraction of graphitic carbon compared to Ti grains with other orientations. This indirect effect of the Ti substrate grain orientation yields new insights into the activity of TiO2 towards the decomposition of carbon precursors.

Morphology design of porous coordination polymer crystals by coordination modulation.

PubMed

Umemura, Ayako; Diring, Stéphane; Furukawa, Shuhei; Uehara, Hiromitsu; Tsuruoka, Takaaki; Kitagawa, Susumu

2011-10-05

The design of crystal morphology, or exposed crystal facets, has enabled the development (e.g., catalytic activities, material attributes, and oriented film formation) of porous coordination polymers (PCPs) without changing material compositions. However, because crystal growth mechanisms are not fully understood, control of crystal morphology still remains challenging. Herein, we report the morphology design of [Cu(3)(btc)(2)](n) (btc = benzene-1,3,5-tricarboxylate) by the coordination modulation method (modulator = n-dodecanoic acid or lauric acid). A morphological transition (octahedron-cuboctahedron-cube) in the [Cu(3)(btc)(2)](n) crystal was observed with an increase in concentration of the modulator. By suitably defining a coarse-grained standard unit of [Cu(3)(btc)(2)](n) as its cuboctahedron main pore and determining its attachment energy on crystal surfaces, Monte Carlo coarse-grain modeling revealed the population and orientation of carboxylates and elucidated an important role of the modulator in determining the <100>- and <111>-growth throughout the crystal growth process. This comprehension, in fact, successfully led to designed crystal morphologies with oriented growth on bare substrates. Because selective crystal orientations on the bare substrates were governed by crystal morphology, this contribution also casts a new light on the unexplored issue of the significance of morphology design of PCPs.

Development of probabilistic thinking-oriented learning tools for probability materials at junior high school students

NASA Astrophysics Data System (ADS)

Sari, Dwi Ivayana; Hermanto, Didik

2017-08-01

This research is a developmental research of probabilistic thinking-oriented learning tools for probability materials at ninth grade students. This study is aimed to produce a good probabilistic thinking-oriented learning tools. The subjects were IX-A students of MTs Model Bangkalan. The stages of this development research used 4-D development model which has been modified into define, design and develop. Teaching learning tools consist of lesson plan, students' worksheet, learning teaching media and students' achievement test. The research instrument used was a sheet of learning tools validation, a sheet of teachers' activities, a sheet of students' activities, students' response questionnaire and students' achievement test. The result of those instruments were analyzed descriptively to answer research objectives. The result was teaching learning tools in which oriented to probabilistic thinking of probability at ninth grade students which has been valid. Since teaching and learning tools have been revised based on validation, and after experiment in class produced that teachers' ability in managing class was effective, students' activities were good, students' responses to the learning tools were positive and the validity, sensitivity and reliability category toward achievement test. In summary, this teaching learning tools can be used by teacher to teach probability for develop students' probabilistic thinking.

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

Lebedev, Oleg V.; N.S. Enikolopov Institute of Synthetic Polymer Materials of RAS, Profsoyuznaya st., Moscow, 117393; Kechek’yan, Alexander S.

Electrically conductive oriented polymer nano-composites of different compositions, based on the reactor powder of ultra-high-molecular-weight polyethylene (UHMWPE) with a special morphology, filled with particles of nanostructured graphite (NG), multi-walled carbon nanotubes (MWCNTs), and electrically conductive carbon black (CB), were investigated. Polymer composites were obtained via compaction of the mechanical mixture of the polymer and filler powder, followed by uniaxial deformation of the material under homogeneous shear (HS) conditions (all of the processing stages were conducted at room temperature). Resulted composites possess a high tensile strength, high level of the electrical conductivity and low percolation threshold, owing it to the formationmore » of the segregated conductive structure, The influence of the type of nanosized carbon filler, degree of the deformation under HS condition, temperature and etc. on the electrical conductivity and mechanical properties of strengthened conductive composites oriented under homogeneous shear conditions was investigated. Changes in the electrical conductivity of oriented composite materials during reversible “tension–shrinkage” cycles along the orientation axis direction were studied. A theoretical approach, describing the process of transformation of the conductive system as a response on polymer phase deformation and volume change, was proposed, based on the data received from the analysis of the conductivity behavior during the uniaxial deformation and thermal treatment of composites.« less

Construction of human induced pluripotent stem cell-derived oriented bone matrix microstructure by using in vitro engineered anisotropic culture model.

PubMed

Ozasa, Ryosuke; Matsugaki, Aira; Isobe, Yoshihiro; Saku, Taro; Yun, Hui-Suk; Nakano, Takayoshi

2018-02-01

Bone tissue has anisotropic microstructure based on collagen/biological apatite orientation, which plays essential roles in the mechanical and biological functions of bone. However, obtaining an appropriate anisotropic microstructure during the bone regeneration process remains a great challenging. A powerful strategy for the control of both differentiation and structural development of newly-formed bone is required in bone tissue engineering, in order to realize functional bone tissue regeneration. In this study, we developed a novel anisotropic culture model by combining human induced pluripotent stem cells (hiPSCs) and artificially-controlled oriented collagen scaffold. The oriented collagen scaffold allowed hiPSCs-derived osteoblast alignment and further construction of anisotropic bone matrix which mimics the bone tissue microstructure. To the best of our knowledge, this is the first report showing the construction of bone mimetic anisotropic bone matrix microstructure from hiPSCs. Moreover, we demonstrated for the first time that the hiPSCs-derived osteoblasts possess a high level of intact functionality to regulate cell alignment. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 360-369, 2018. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.

Doped titanium oxide photcatalysts: Preparation, structure and interaction with viruses

NASA Astrophysics Data System (ADS)

Li, Qi

Since the discovery of photoelectrochemical splitting of water on n-titanium oxide (n-TiO2) electrodes by Fujishima and Honda in 1972, there has been much interest in semiconductor-based materials as photocatalysts for both solar energy conversion and environmental applications in the past several decades. Among various semiconductor-based photocatalysts, TiO2 is the only candidate suitable for industrial use because of its high chemical stability, good photoactivity, relatively low cost, and nontoxicity. However, the photocatalytic capability of TiO 2 is limited to only ultraviolet (UV) light (wavelength, lambda, < 400 nm), seriously limiting its solar efficiency. In this study, both chemical and physical modification approaches were developed to extend the absorption band-edge of TiO2 into the visible light region with improved stability, photocatalytic efficiency and ease of the doping process. Two major approaches were used in the material synthesis and processing, including the ion-beam-assisted-deposition (IBAD) technique and sol-gel based processes. Both nitrogen-doped TiO2 (TiON) and nitrogen/palladium co-doped TiO2 (TiON/PdO) photocatalysts were created and their photocatalytic activity was investigated by the degradation of methylene blue (MB) and disinfection of bacteria and viruses under visible light illumination. The sol-gel process was optimized to produce high quality TiON-based photocatalysts by carefully modulating the precursor ratio and calcination temperature. A TiON inverse opal structure was created, which demonstrated enhanced visible light absorption and subsequently improved photocatalytic efficiency by the combination of chemical and physical modifications on n-TiO2. The effect of palladium dopant on the optical and photocatalytic properties of TiON/PdO photocatalyst was examined, which suggests that a careful optimization of the transition metal ion dopant concentration is needed to achieve high photocatalytic efficiency in these anion and transition metal ion co-doped TiO2 photocatalysts. High photocatalytic virus disinfection efficiency under visible-light illumination was observed for the first time with TiON/PdO photocatalyst, and the interaction between MS2 virus and TiO2-based semiconductor surfaces was successfully modulated. A strategy to use atomic force microscope (AFM) to conduct in-situ observation of viruses on semiconductor surfaces in aqueous environment was developed, which combines information from both height profile and phase profile and solves the difficulty of observing small nanosized biomolecules on substrates with similar feature sizes.

Orientation-Dependent Exciton-Plasmon Coupling in Embedded Organic/Metal Nanowire Heterostructures.

PubMed

Li, Yong Jun; Hong, Yan; Peng, Qian; Yao, Jiannian; Zhao, Yong Sheng

2017-10-24

The excitation of surface plasmons by optical emitters based on exciton-plasmon coupling is important for plasmonic devices with active optical properties. It has been theoretically demonstrated that the orientation of exciton dipole can significantly influence the coupling strength, yet systematic study of the coupling process in nanostructures is still hindered by the lack of proper material systems. In this work, we have experimentally investigated the orientation-dependent exciton-plasmon coupling in a rationally designed organic/metal nanowire heterostructure system. The heterostructures were prepared by inserting silver nanowires into crystalline organic waveguides during the self-assembly of dye molecules. Structures with different exciton orientations exhibited varying coupling efficiencies. The near-field exciton-plasmon coupling facilitates the design of nanophotonic devices based on the directional surface plasmon polariton propagations.

Electrophysiological correlates of retrieval orientation in reality monitoring.

PubMed

Rosburg, Timm; Mecklinger, Axel; Johansson, Mikael

2011-02-14

Retrieval orientation describes the modulation in the processing of retrieval cues by the nature of the targeted material in memory. Retrieval orientation is usually investigated by analyzing the cortical responses to new (unstudied) material when different memory contents are targeted. This approach avoids confounding effects of retrieval success. We investigated the neural correlates of retrieval orientation in reality monitoring with event-related potentials (ERPs) and assessed the impact of retrieval accuracy on obtained ERP measures. Thirty-two subjects studied visually presented object names that were followed either by a picture of that object (perceived condition) or by the instruction to mentally generate such a picture (imagine condition). Subsequently, subjects had to identify object names of one study condition and reject object names of the second study condition together with newly presented object names. The data analysis showed that object names were more accurately identified when they had been presented in the perceived condition. Two topographically distinct ERP effects of retrieval orientation were revealed: From 600 to 1100 ms after stimulus representation, ERPs were more positive at frontal electrode sites when object names from the imagine condition were targeted. The analysis of response-locked ERP data revealed an additional effect at posterior electrode sites, with more negative ERPs shortly after response onset when items from the imagine condition were targeted. The ERP effect at frontal electrode sites, but not at posterior electrode sites was modulated by relative memory accuracy, with stronger effects in subjects who had lower memory accuracy for items of the imagine condition. The findings are suggestive for a contribution of frontal brain areas to retrieval orientation processes in reality monitoring and indicate that neural correlates of retrieval orientation can be modulated by retrieval effort, with stronger activation of these correlates with increasing task demands. Copyright © 2010 Elsevier Inc. All rights reserved.

Assembly of Layered Monetite-Chitosan Nanocomposite and Its Transition to Organized Hydroxyapatite.

PubMed

Ruan, Qichao; Liberman, David; Zhang, Yuzheng; Ren, Dongni; Zhang, Yunpeng; Nutt, Steven; Moradian-Oldak, Janet

2016-06-13

Bioinspired synthesis of hierarchically structured calcium phosphate (CaP) material is a highly promising strategy for developing improved bone substitute materials. However, synthesis of CaP materials with outstanding mechanical properties still remains an ongoing challenge. Inspired by the formation of lamellar structure in nacre, we designed an organic matrix composed of chitosan and cis-butenediolic acid (maleic acid, MAc) that could assemble into a layered complex and further guide the mineralization of monetite crystals, resulting in the formation of organized and parallel arrays of monetite platelets with a brick-and-mortar structure. Using the layered monetite-chitosan composite as a precursor, we were able to synthesize hydroxyapatite (HAp) with multiscale hierarchically ordered structure via a topotactic phase transformation process. On the nanoscale, needlelike HAp crystallites assembled into organized bundles that aligned to form highly oriented plates on the microscale. On the large-scale level, these plates with different crystal orientations were stacked together to form a layered structure. The organized structures and composite feature yielded CaP materials with improved mechanical properties close to those of bone. Our study introduces a biomimetic approach that may be practical for the design of advanced, mechanically robust materials for biomedical applications.

Cross-talk between topological defects in different fields revealed by nematic microfluidics

PubMed Central

Giomi, Luca; Kos, Žiga; Ravnik, Miha

2017-01-01

Topological defects are singularities in material fields that play a vital role across a range of systems: from cosmic microwave background polarization to superconductors and biological materials. Although topological defects and their mutual interactions have been extensively studied, little is known about the interplay between defects in different fields—especially when they coevolve—within the same physical system. Here, using nematic microfluidics, we study the cross-talk of topological defects in two different material fields—the velocity field and the molecular orientational field. Specifically, we generate hydrodynamic stagnation points of different topological charges at the center of star-shaped microfluidic junctions, which then interact with emergent topological defects in the orientational field of the nematic director. We combine experiments and analytical and numerical calculations to show that a hydrodynamic singularity of a given topological charge can nucleate a nematic defect of equal topological charge and corroborate this by creating −1, −2, and −3 topological defects in four-, six-, and eight-arm junctions. Our work is an attempt toward understanding materials that are governed by distinctly multifield topology, where disparate topology-carrying fields are coupled and concertedly determine the material properties and response. PMID:28674012

Testing the Accuracy of Different A-Axis Types for Measuring the Orientation of Bones in the Archaeological and Paleontological Record

PubMed Central

Domínguez-Rodrigo, Manuel; García-Pérez, Alfonso

2013-01-01

Orientation of archaeological and paleontological materials plays a prominent role in the interpretation of site formation processes. Allochthony and authochthony are frequently assumed from orientation patterns or lack thereof. Although it is still debated to what extent orientation of items can be produced in original depositional contexts, the recent use of GIS tools to measure orientations has highlighted several ways of reproducing A-axes with which to address these taphonomic issues. In the present study, the three most relevant A-axis types are compared to test their accuracy in reproducing water current direction. Although results may be similar in specific bone shapes, differences are important in other shapes. As known in engineering working with wind and fluid mechanics (developing shape optimization), longitudinal symmetrical axes (LSA) are the one that best orient structures against or in the same direction of wind and water. The present work shows that this is also the case for bones (regardless of shape), since LSA produce the most accurate estimates of flow direction. This has important consequences for the interpretation of orientation patterns at sites, since this type of axis is still not properly reproduced by GIS available tools. PMID:23874825

Development of eddy current probe for fiber orientation assessment in carbon fiber composites

NASA Astrophysics Data System (ADS)

Wincheski, Russell A.; Zhao, Selina

2018-04-01

Measurement of the fiber orientation in a carbon fiber composite material is crucial in understanding the load carrying capability of the structure. As manufacturing conditions including resin flow and molding pressures can alter fiber orientation, verification of the as-designed fiber layup is necessary to ensure optimal performance of the structure. In this work, the development of an eddy current probe and data processing technique for analysis of fiber orientation in carbon fiber composites is presented. A proposed directional eddy current probe is modeled and its response to an anisotropic multi-layer conductor simulated. The modeling results are then used to finalize specifications of the eddy current probe. Experimental testing of the fabricated probe is presented for several samples including a truncated pyramid part with complex fiber orientation draped to the geometry for resin transfer molding. The inductively coupled single sided measurement enables fiber orientation characterization through the thickness of the part. The fast and cost-effective technique can be applied as a spot check or as a surface map of the fiber orientations across the structure. This paper will detail the results of the probe design, computer simulations, and experimental results.

Free-standing oxide superconducting articles

DOEpatents

Wu, Xin D.; Muenchausen, Ross E.

1993-01-01

A substrate-free, free-standing epitaxially oriented superconductive film including a layer of a template material and a layer of a ceramic superconducting material is provided together with a method of making such a substrate-free ceramic superconductive film by coating an etchable material with a template layer, coating the template layer with a layer of a ceramic superconductive material, coating the layer of ceramic superconductive material with a protective material, removing the etchable material by an appropriate means so that the etchable material is separated from a composite structure including the template lay This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

Orientation relationship of eutectoid FeAl and FeAl2.

PubMed

Scherf, A; Kauffmann, A; Kauffmann-Weiss, S; Scherer, T; Li, X; Stein, F; Heilmaier, M

2016-04-01

Fe-Al alloys in the aluminium range of 55-65 at.% exhibit a lamellar microstructure of B2-ordered FeAl and triclinic FeAl 2 , which is caused by a eutectoid decomposition of the high-temperature Fe 5 Al 8 phase, the so-called ∊ phase. The orientation relationship of FeAl and FeAl 2 has previously been studied by Bastin et al. [ J. Cryst. Growth (1978 ▸), 43 , 745] and Hirata et al. [ Philos. Mag. Lett. (2008 ▸), 88 , 491]. Since both results are based on different crystallographic data regarding FeAl 2 , the data are re-evaluated with respect to a recent re-determination of the FeAl 2 phase provided by Chumak et al. [ Acta Cryst. (2010 ▸), C 66 , i87]. It is found that both orientation relationships match subsequent to a rotation operation of 180° about a 〈112〉 crystallographic axis of FeAl or by applying the inversion symmetry of the FeAl 2 crystal structure as suggested by the Chumak data set. Experimental evidence for the validity of the previously determined orientation relationships was found in as-cast fully lamellar material (random texture) as well as directionally solidified material (∼〈110〉 FeAl || solidification direction) by means of orientation imaging microscopy and global texture measurements. In addition, a preferential interface between FeAl and FeAl 2 was identified by means of trace analyses using cross sectioning with a focused ion beam. On the basis of these habit planes the orientation relationship between the two phases can be described by ([Formula: see text]01) FeAl || (114)[Formula: see text] and [111] FeAl || [1[Formula: see text]0][Formula: see text]. There is no evidence for twinning within FeAl lamellae or alternating orientations of FeAl lamellae. Based on the determined orientation and interface data, an atomistic model of the structure relationship of Fe 5 Al 8 , FeAl and FeAl 2 in the vicinity of the eutectoid decomposition is derived. This model is analysed with respect to the strain which has to be accommodated at the interface of FeAl and FeAl 2 .

Tensile strength of various nylon PA6 specimen modes

NASA Astrophysics Data System (ADS)

Raz, Karel; Zahalka, Martin

2017-05-01

This article explores the influence of production technique on the strength of nylon parts. Identical specimens were manufactured by various techniques. The material of specimens was nylon PA6. 3D printing and injection molding were used, with various orientations of printed layers, and various orientations of specimens in the working space of the 3D printer. The variants are described in detail. A special mold was used for the injection molding process in order to make specimens with and without a weld line. The effect of this weld line was evaluated. All specimens were tested using the standard tensile test configuration. The strength was compared. It was found that the same plastic material has very different mechanical properties depending on the production process.

Variation in Pockels constants of silicate glass-ceramics prepared by perfect surface crystallization

NASA Astrophysics Data System (ADS)

Takano, Kazuya; Takahashi, Yoshihiro; Miyazaki, Takamichi; Terakado, Nobuaki; Fujiwara, Takumi

2018-01-01

We investigated the Pockels effect in polycrystalline materials consisting of highly oriented polar fresnoite-type Sr2TiSi2O8 fabricated using perfectly surface-crystallized glass-ceramics (PSC-GCs). The chemical composition of the precursor glass was shown to significantly affect the crystallized texture, e.g., the crystal orientation and appearance of amorphous nanoparasites in the domains, resulting in variations in the Pockels constants. Single crystals exhibiting spontaneous polarization possessed large structural anisotropy, leading to a strong dependence of the nonlinear-optical properties on the direction of polarized light. This study suggests that variations in the Pockels constants (r13 and r33) and tuning of the r13/r33 ratio can be realized in PSC-GC materials.

Superconducting magnetic coil

DOEpatents

Aized, D.; Schwall, R.E.

1999-06-22

A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil. 15 figs.

Space environmental effects on silvered Teflon thermal control surfaces

NASA Technical Reports Server (NTRS)

Hemminger, C. S.; Stuckey, W. K.; Uht, J. C.

1991-01-01

Cumulative space environment effects on Ag/fluorinated ethylene propylene (FEP) were a function of exposure orientation. Samples from nineteen silvered Teflon (Ag/FEP) thermal control surfaces recovered from the Long Duration Exposure Facility (LDEF) were analyzed to determine changes in this material as a function of position on the spacecraft. Although solar absorptance and infrared emittance of measured thermal blanket specimens are relatively unchanged from control specimen values, significant changes in surface morphology, composition and chemistry were observed. Researchers hypothesize that the FEP surfaces on LDEF were degraded by ultraviolet radiation exposure at all orientations, but that the damaged material had been removed by erosion from the blankets exposed to atomic oxygen flux and that contamination is masking the damage on trays flanking the trailing edge.

Calibration of a Background Oriented Schlieren (BOS) Set-up

NASA Astrophysics Data System (ADS)

Porta, David; Echeverría, Carlos; Cardoso, Hiroki; Aguayo, Alejandro; Stern, Catalina

2014-11-01

We use two materials with different known indexes of refraction to calibrate a Background Oriented Schlieren (BOS) experimental set-up, and to validate the Lorenz-Lorentz equation. BOS is used in our experiments to determine local changes of density in the shock pattern of an axisymmetric supersonic air jet. It is important to validate, in particular, the Gladstone Dale approximation (index of refraction close to one) in our experimental conditions and determine the uncertainty of our density measurements. In some cases, the index of refraction of the material is well known, but in others the density is measured and related to the displacement field. We acknowledge support from UNAM through DGAPA PAPIIT IN117712 and the Graduate Program in Mechanical Engineering.

Ordered macro-microporous metal-organic framework single crystals

NASA Astrophysics Data System (ADS)

Shen, Kui; Zhang, Lei; Chen, Xiaodong; Liu, Lingmei; Zhang, Daliang; Han, Yu; Chen, Junying; Long, Jilan; Luque, Rafael; Li, Yingwei; Chen, Banglin

2018-01-01

We constructed highly oriented and ordered macropores within metal-organic framework (MOF) single crystals, opening up the area of three-dimensional–ordered macro-microporous materials (that is, materials containing both macro- and micropores) in single-crystalline form. Our methodology relies on the strong shaping effects of a polystyrene nanosphere monolith template and a double-solvent–induced heterogeneous nucleation approach. This process synergistically enabled the in situ growth of MOFs within ordered voids, rendering a single crystal with oriented and ordered macro-microporous structure. The improved mass diffusion properties of such hierarchical frameworks, together with their robust single-crystalline nature, endow them with superior catalytic activity and recyclability for bulky-molecule reactions, as compared with conventional, polycrystalline hollow, and disordered macroporous ZIF-8.

Using aligned poly(3-hexylthiophene)/poly(methyl methacrylate) blend fibers to detect volatile organic compounds

NASA Astrophysics Data System (ADS)

Chan, Shun-Hsiang; Lin, Tz-Feng; Wu, Ming-Chung; Chen, Shih-Hsuan; Su, Wei-Fang; Lai, Chao-Sung

2018-04-01

In this study, we developed a novel sensing material fabricated using a poly(3-hexylthiophene) (P3HT)/poly(methyl methacrylate) (PMMA) blend fiber on a glass substrate. The sensing materials can easily be used for sensing toluene vapor detected from extinction spectral changes. The extinction spectra variation is noted from the absorption of volatile organic compounds in a highly specific surface area of fibrous coating. An electrospinning technique is applied to generate a nonwoven structure and uniaxial orientation by fibrous coating. The response of the uniaxially orientated fibrous film is even improved at several toluene vapor concentrations. The best detection limit of this well-aligned fibrous film is up to 200 ppm for toluene vapor.

High spatial resolution grain orientation and strain mapping in thin films using polychromatic submicron x-ray diffraction

NASA Astrophysics Data System (ADS)

Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Valek, B.; Bravman, J. C.; Spolenak, R.; Brown, W. L.; Marieb, T.; Fujimoto, H.; Batterman, B. W.; Patel, J. R.

2002-05-01

The availability of high brilliance synchrotron sources, coupled with recent progress in achromatic focusing optics and large area two-dimensional detector technology, has allowed us to develop an x-ray synchrotron technique that is capable of mapping orientation and strain/stress in polycrystalline thin films with submicron spatial resolution. To demonstrate the capabilities of this instrument, we have employed it to study the microstructure of aluminum thin film structures at the granular and subgranular levels. Due to the relatively low absorption of x-rays in materials, this technique can be used to study passivated samples, an important advantage over most electron probes given the very different mechanical behavior of buried and unpassivated materials.

Textural analyses of carbon fiber materials by 2D-FFT of complex images obtained by high frequency eddy current imaging (HF-ECI)

NASA Astrophysics Data System (ADS)

Schulze, Martin H.; Heuer, Henning

2012-04-01

Carbon fiber based materials are used in many lightweight applications in aeronautical, automotive, machine and civil engineering application. By the increasing automation in the production process of CFRP laminates a manual optical inspection of each resin transfer molding (RTM) layer is not practicable. Due to the limitation to surface inspection, the quality parameters of multilayer 3 dimensional materials cannot be observed by optical systems. The Imaging Eddy- Current (EC) NDT is the only suitable inspection method for non-resin materials in the textile state that allows an inspection of surface and hidden layers in parallel. The HF-ECI method has the capability to measure layer displacements (misaligned angle orientations) and gap sizes in a multilayer carbon fiber structure. EC technique uses the variation of the electrical conductivity of carbon based materials to obtain material properties. Beside the determination of textural parameters like layer orientation and gap sizes between rovings, the detection of foreign polymer particles, fuzzy balls or visualization of undulations can be done by the method. For all of these typical parameters an imaging classification process chain based on a high resolving directional ECimaging device named EddyCus® MPECS and a 2D-FFT with adapted preprocessing algorithms are developed.

Study on Crystallographic Orientation Effect on Surface Generation of Aluminum in Nano-cutting

NASA Astrophysics Data System (ADS)

Xu, Feifei; Fang, Fengzhou; Zhu, Yuanqing; Zhang, Xiaodong

2017-04-01

The material characteristics such as size effect are one of the most important factors that could not be neglected in cutting the material at nanoscale. The effects of anisotropic nature of single crystal materials in nano-cutting are investigated employing the molecular dynamics simulation. Results show that the size effect of the plastic deformation is based on different plastic carriers, such as the twin, stacking faults, and dislocations. The minimum uncut chip thickness is dependent on cutting direction, where even a negative value is obtained when the cutting direction is {110}<001>. It also determines the material deformation and removal mechanism (e.g., shearing, extruding, and rubbing mechanism) with a decrease in uncut chip thickness. When material is deformed by shearing, the primary shearing zone expands from the stagnation point or the tip of stagnation zone. When a material is deformed by extruding and rubbing, the primary deformation zone almost parallels to the cutting direction and expands from the bottom of the cutting edge merging with the tertiary deformation zone. The generated surface quality relates to the crystallographic orientation and the minimum uncut chip thickness. The cutting directions of {110}<001>, {110}<1-10>, and {111}<1-10>, whose minimum uncut chip thickness is relatively small, have better surface qualities compared to the other cutting direction.

Study on Crystallographic Orientation Effect on Surface Generation of Aluminum in Nano-cutting.

PubMed

Xu, Feifei; Fang, Fengzhou; Zhu, Yuanqing; Zhang, Xiaodong

2017-12-01

The material characteristics such as size effect are one of the most important factors that could not be neglected in cutting the material at nanoscale. The effects of anisotropic nature of single crystal materials in nano-cutting are investigated employing the molecular dynamics simulation. Results show that the size effect of the plastic deformation is based on different plastic carriers, such as the twin, stacking faults, and dislocations. The minimum uncut chip thickness is dependent on cutting direction, where even a negative value is obtained when the cutting direction is {110}<001>. It also determines the material deformation and removal mechanism (e.g., shearing, extruding, and rubbing mechanism) with a decrease in uncut chip thickness. When material is deformed by shearing, the primary shearing zone expands from the stagnation point or the tip of stagnation zone. When a material is deformed by extruding and rubbing, the primary deformation zone almost parallels to the cutting direction and expands from the bottom of the cutting edge merging with the tertiary deformation zone. The generated surface quality relates to the crystallographic orientation and the minimum uncut chip thickness. The cutting directions of {110}<001>, {110}<1-10>, and {111}<1-10>, whose minimum uncut chip thickness is relatively small, have better surface qualities compared to the other cutting direction.

Structure and crystallography of foliated and chalk shell microstructures of the oyster Magallana: the same materials grown under different conditions.

PubMed

Checa, Antonio G; Harper, Elizabeth M; González-Segura, Alicia

2018-05-14

Oyster shells are mainly composed of layers of foliated microstructure and lenses of chalk, a highly porous, apparently poorly organized and mechanically weak material. We performed a structural and crystallographic study of both materials, paying attention to the transitions between them. The morphology and crystallography of the laths comprising both microstructures are similar. The main differences were, in general, crystallographic orientation and texture. Whereas the foliated microstructure has a moderate sheet texture, with a defined 001 maximum, the chalk has a much weaker sheet texture, with a defined 011 maximum. This is striking because of the much more disorganized aspect of the chalk. We hypothesize that part of the unanticipated order is inherited from the foliated microstructure by means of, possibly, [Formula: see text] twinning. Growth line distribution suggests that during chalk formation, the mantle separates from the previous shell several times faster than for the foliated material. A shortage of structural material causes the chalk to become highly porous and allows crystals to reorient at a high angle to the mantle surface, with which they continue to keep contact. In conclusion, both materials are structurally similar and the differences in orientation and aspect simply result from differences in growth conditions.

Noncontact orientation of objects in three-dimensional space using magnetic levitation

PubMed Central

Subramaniam, Anand Bala; Yang, Dian; Yu, Hai-Dong; Nemiroski, Alex; Tricard, Simon; Ellerbee, Audrey K.; Soh, Siowling; Whitesides, George M.

2014-01-01

This paper describes several noncontact methods of orienting objects in 3D space using Magnetic Levitation (MagLev). The methods use two permanent magnets arranged coaxially with like poles facing and a container containing a paramagnetic liquid in which the objects are suspended. Absent external forcing, objects levitating in the device adopt predictable static orientations; the orientation depends on the shape and distribution of mass within the objects. The orientation of objects of uniform density in the MagLev device shows a sharp geometry-dependent transition: an analytical theory rationalizes this transition and predicts the orientation of objects in the MagLev device. Manipulation of the orientation of the levitating objects in space is achieved in two ways: (i) by rotating and/or translating the MagLev device while the objects are suspended in the paramagnetic solution between the magnets; (ii) by moving a small external magnet close to the levitating objects while keeping the device stationary. Unlike mechanical agitation or robotic selection, orienting using MagLev is possible for objects having a range of different physical characteristics (e.g., different shapes, sizes, and mechanical properties from hard polymers to gels and fluids). MagLev thus has the potential to be useful for sorting and positioning components in 3D space, orienting objects for assembly, constructing noncontact devices, and assembling objects composed of soft materials such as hydrogels, elastomers, and jammed granular media. PMID:25157136

Noncontact orientation of objects in three-dimensional space using magnetic levitation.

PubMed

Subramaniam, Anand Bala; Yang, Dian; Yu, Hai-Dong; Nemiroski, Alex; Tricard, Simon; Ellerbee, Audrey K; Soh, Siowling; Whitesides, George M

2014-09-09

This paper describes several noncontact methods of orienting objects in 3D space using Magnetic Levitation (MagLev). The methods use two permanent magnets arranged coaxially with like poles facing and a container containing a paramagnetic liquid in which the objects are suspended. Absent external forcing, objects levitating in the device adopt predictable static orientations; the orientation depends on the shape and distribution of mass within the objects. The orientation of objects of uniform density in the MagLev device shows a sharp geometry-dependent transition: an analytical theory rationalizes this transition and predicts the orientation of objects in the MagLev device. Manipulation of the orientation of the levitating objects in space is achieved in two ways: (i) by rotating and/or translating the MagLev device while the objects are suspended in the paramagnetic solution between the magnets; (ii) by moving a small external magnet close to the levitating objects while keeping the device stationary. Unlike mechanical agitation or robotic selection, orienting using MagLev is possible for objects having a range of different physical characteristics (e.g., different shapes, sizes, and mechanical properties from hard polymers to gels and fluids). MagLev thus has the potential to be useful for sorting and positioning components in 3D space, orienting objects for assembly, constructing noncontact devices, and assembling objects composed of soft materials such as hydrogels, elastomers, and jammed granular media.

Application of Colloidal Filtration Theory on Textile Fibrous Media: Effect of Fiber Orientation on Bacterial Removal Efficiency and Attachment

NASA Astrophysics Data System (ADS)

Roy, Sukumar; Ghosh, Subrata; Bhowmick, Niranjan

2018-06-01

A mechanism to remove the Pseudomonas bacteria from contaminated water by using textile fibrous media has been proposed in this article. The attachment of Pseudomonas bacteria on nylon fibrous media was studied in laboratory column experiment. A systematic study was carried out to investigate the attachment of bacteria on the fibrous material as a function of fiber orientation to the direction of the liquid flow. Three types of textiles media with different orientation fiber were selected for the experiment (i.e. 0°, 45° and 90°). It was found that the bacteria removal efficiency was comparatively higher at 90° orientation as compared to that of 45° and 0° orientation of fibrous media, suggesting that the removal efficiency of bacteria (1 - Fp) was depended on fiber orientation. The removal trends were explained on the basis of colloidal filtration theory. This is due to the higher single collector contact efficiency and attachment/collision efficiency as observed from the experimental data of removal efficiency.

Crystal orientation dependence of femtosecond laser-induced periodic surface structure on (100) silicon.

PubMed

Jiang, Lan; Han, Weina; Li, Xiaowei; Wang, Qingsong; Meng, Fantong; Lu, Yongfeng

2014-06-01

It is widely believed that laser-induced periodic surface structures (LIPSS) are independent of material crystal structures. This Letter reports an abnormal phenomenon of strong dependence of the anisotropic formation of periodic ripples on crystal orientation, when Si (100) is processed by a linearly polarized femtosecond laser (800 nm, 50 fs, 1 kHz). LIPSS formation sensitivity with a π/2 modulation is found along different crystal orientations with a quasi-cosinusoid function when the angle between the crystal orientation and polarization direction is changed from 0° to 180°. Our experiments indicate that it is much easier (or more difficult) to form ripple structures when the polarization direction is aligned with the lattice axis [011]/[011¯] (or [001]). The modulated nonlinear ionization rate along different crystal orientations, which arises from the direction dependence of the effective mass of the electron is proposed to interpret the unexpected anisotropic LIPSS formation phenomenon. Also, we demonstrate that the abnormal phenomenon can be applied to control the continuity of scanned ripple lines along different crystal orientations.

Application of Colloidal Filtration Theory on Textile Fibrous Media: Effect of Fiber Orientation on Bacterial Removal Efficiency and Attachment

NASA Astrophysics Data System (ADS)

Roy, Sukumar; Ghosh, Subrata; Bhowmick, Niranjan

2018-05-01

A mechanism to remove the Pseudomonas bacteria from contaminated water by using textile fibrous media has been proposed in this article. The attachment of Pseudomonas bacteria on nylon fibrous media was studied in laboratory column experiment. A systematic study was carried out to investigate the attachment of bacteria on the fibrous material as a function of fiber orientation to the direction of the liquid flow. Three types of textiles media with different orientation fiber were selected for the experiment (i.e. 0°, 45° and 90°). It was found that the bacteria removal efficiency was comparatively higher at 90° orientation as compared to that of 45° and 0° orientation of fibrous media, suggesting that the removal efficiency of bacteria (1 - Fp) was depended on fiber orientation. The removal trends were explained on the basis of colloidal filtration theory. This is due to the higher single collector contact efficiency and attachment/collision efficiency as observed from the experimental data of removal efficiency.

Computer simulation of ion beam analysis of laterally inhomogeneous materials

NASA Astrophysics Data System (ADS)

Mayer, M.

2016-03-01

The program STRUCTNRA for the simulation of ion beam analysis charged particle spectra from arbitrary two-dimensional distributions of materials is described. The code is validated by comparison to experimental backscattering data from a silicon grating on tantalum at different orientations and incident angles. Simulated spectra for several types of rough thin layers and a chessboard-like arrangement of materials as example for a multi-phase agglomerate material are presented. Ambiguities between back-scattering spectra from two-dimensional and one-dimensional sample structures are discussed.

Life on Guam: Coral Reef. 1977 Edition.

ERIC Educational Resources Information Center

Randall, Richard H.; Eldredge, L. G.

As part of an updated series of activity oriented educational materials dealing with aspects of the Guam environment, this publication deals primarily with the marine environment of Guam. Developed for junior and senior high school students of this island, this material can be adapted to marine studies in other areas as well. Contents deal with…

Money Management. Teaching Guide.

ERIC Educational Resources Information Center

Florida Univ., Gainesville. Florida Cooperative Extension Service.

This document, one in a series of consumer education materials for 4-H Club members and secondary students, focuses on money management. The materials are based on the premise that an understanding of the management of money is vital if one is to be prepared to meet the challenges of the economically oriented society. Specific objectives are for…

Learners' Perceptions of a Reading Section without Instruction

ERIC Educational Resources Information Center

Mulling, Alessandra Belletti Figueira

2017-01-01

This study highlights learners' perceptions about their experience with self-access materials with a qualitative orientation as the best way to understand nuances of how students learn and what they need from learning materials. This paper presents English as a foreign language learners' attitudes when interacting with the computer-reading section…

General Anisotropy Identification of Paperboard with Virtual Fields Method

Treesearch

J.M. Considine; F. Pierron; K.T. Turner; D.W. Vahey

2014-01-01

This work extends previous efforts in plate bending of Virtual Fields Method (VFM) parameter identification to include a general 2-D anisotropicmaterial. Such an extension was needed for instances in which material principal directions are unknown or when specimen orientation is not aligned with material principal directions. A new fixture with a multiaxial force...

Adhesives with wood materials : bond formation and performance

Treesearch

Charles R. Frihart; Christopher G. Hunt

2010-01-01

Adhesive bonding of wood plays an increasing role in the forest products industry and is a key factor for efficiently utilizing our timber resource. The main use of adhesives is in the manufacture of building materials, including plywood, oriented strandboard, particleboard, fiberboard, structural composite lumber, doors, windows and frames, and factory-laminated wood...

Graphic Arts: Orientation, Composition, and Paste-Up. Teacher Guide.

ERIC Educational Resources Information Center

Feasley, Sue C., Ed.

This curriculum guide is the first in a three-volume series of instructional materials for competency-based graphic arts instruction. Each publication is designed to include the technical content and tasks necessary for a student to be employed in an entry-level graphic arts occupation. Introductory materials include an instructional/task analysis…

RUPS: Research Utilizing Problem Solving. Administrators Version. Participant Materials.

ERIC Educational Resources Information Center

Jung, Charles; And Others

These materials are the handouts for school administrators participating in RUPS (Research Utilizing Problem Solving) workshops. The purposes of the workshops are to develop skills for improving schools and to increase teamwork skills. The handouts correspond to the 16 subsets that make up the five-day workshop: (1) orientation; (2) identifying…

The Effects of Learned Leadership/Membership Skills on Work Performance. Final Report.

ERIC Educational Resources Information Center

Banathy, Bela H.; And Others

The project examined the effects of learned leadership/membership skills on performance in task-oriented groups, developed competence-based instructional materials to teach such skills, and examined the effects of such skills on individual and group knowledge, skills, attitudes, and performance. Following a literature review, materials review, and…

From Autos To Stereos. A Collection of Readings.

ERIC Educational Resources Information Center

Ferri, Kathy

Designed to provide materials which the high school teacher can use to teach some of the basic reading skills or as supplementary reading material, this guide is composed of thirty-five articles of general interest which are vocationally oriented, followed by exercises designed to test comprehension and to teach reading concepts. The articles have…

Material Culture and American Domestic Life: The Kitchen, 1890-1914.

ERIC Educational Resources Information Center

McBride, Lawrence W.

This teacher's guide is designed to provide elementary and secondary students with an orientation to material culture studies and an exposure to such artifacts as sad irons, washboards, butter churns, butter molds, and waffle irons. Information is also provided about wages, employment, industrial development, and advertising in the United States…

Career Oriented Mathematics, Student's Manual. [Includes Scale; Apprenticeship: Learning to be a Cement Mason; Textiles; Being Self-Employed: Harvesting and Sale of Pulpwood; and Lumber Yard Employee.

ERIC Educational Resources Information Center

Mahaffey, Michael L.; McKillip, William D.

This volume includes student manuals for five units in the Career Oriented Mathematics Program, which was developed to improve mathematical abilities and attitudes of secondary students by presenting the material in a job-relevant context. The units are titled: (1) Scale, (2) Apprenticeship: Learning to be a Cement Mason, (3) Textiles, (4) Being…

The Axial Compressive Strength of High Performance Polymer Fibers

DTIC Science & Technology

1985-03-01

consists of axially oriented graphitic microfibrils that have the strong and stiff graphite crystal basal plane oriented parallel to the long axis of the... microfibrils [3,4]. The synthetic rigid polymer fibers are represented by only one commercial material: the PPTA fibers produced by E.I. DuPont de...and/or microfibrils is presented. A potential energy balance analysis is used to calculate critical stresses for the onset of compressive buckling

Orientation to Employment in the U.S. for Refugees--Vietnamese = Cong an viec lam o Hoa Ky: Tap Huong Dan danh cho Nguoi Ti Nan moi toi.

ERIC Educational Resources Information Center

Center for Applied Linguistics, Washington, DC. Language and Orientation Resource Center.

One of a series of refugee orientation materials, this guide to employment is intended to assist Vietnamese refugees in their understanding of the employment situation in the United States and to give them necessary information for obtaining work. The text is in Vietnamese followed by an English-language version, which is not an exact translation…

Research and Development Project to Develop, Improve, Expand and Evaluate Behavioral Goals of a Team-Taught, Humanities-Oriented Course in World Civilization for Ninth and Tenth Grade Students. Final Report.

ERIC Educational Resources Information Center

Fairfax County School Board, VA.

This report describes five out of seventeen units in a World Civilization program, a two-year humanities oriented interdisciplinary English and social studies program. Course material focuses on those records of man which represent his thoughts and feelings about life. History serves as the basis for the chronological development of the course,…

The relationship between the mechanical anisotropy of human cortical bone tissue and its microstructure

NASA Astrophysics Data System (ADS)

Espinoza Orias, Alejandro A.

Orthopedics research has made significant advances in the areas of biomechanics, bone implants and bone substitute materials. However, to date there is no definitive model to explain the structure-property relationships in bone as a material to enable better implant designs or to develop a true biomechanical analog of bone. The objective of this investigation was to establish a relationship between the elastic anisotropy of cortical bone tissue and its microstructure. Ultrasonic wave propagation was used to measure stiffness coefficients for specimens sectioned along the length of a human femur. The elastic constants were orthotropic and varied with anatomical location. Stiffness coefficients were generally largest at the midshaft and stiffness anisotropy ratios were largest at the distal and proximal ends. These tests were run on four additional human femurs to assess the influence of phenotypic variation, and in most cases, it was found that phenotypes do not exert a significant effect. Stiffness coefficients were shown to be correlated as a power law relation to apparent density, but anisotropy ratios were not. Texture analysis was performed on selected samples to measure the orientation distribution of the bone mineral crystals. Inverse pole figures showed that bone mineral crystals had a preferred crystallographic orientation, coincident with the long axis of the femur, which is its principal loading direction. The degree of preferred orientation was represented in Multiples of a Random Distribution (MRD), and correlated to the anisotropy ratios. Variation in elastic anisotropy was shown to be primarily due to the bone mineral orientation. The results found in this work can be used to incorporate anisotropy into structural analysis for bone as a material.

Backscattered Diffraction | Materials Science | NREL

Science.gov Websites

crystalline orientation (left) and grain distribution (right). EBSD images showing properties of crystalline investigate misorientation between grain boundaries, texture, grain distribution, deformation, strain, and

Tissue Anisotropy Modeling Using Soft Composite Materials.

PubMed

Chanda, Arnab; Callaway, Christian

2018-01-01

Soft tissues in general exhibit anisotropic mechanical behavior, which varies in three dimensions based on the location of the tissue in the body. In the past, there have been few attempts to numerically model tissue anisotropy using composite-based formulations (involving fibers embedded within a matrix material). However, so far, tissue anisotropy has not been modeled experimentally. In the current work, novel elastomer-based soft composite materials were developed in the form of experimental test coupons, to model the macroscopic anisotropy in tissue mechanical properties. A soft elastomer matrix was fabricated, and fibers made of a stiffer elastomer material were embedded within the matrix material to generate the test coupons. The coupons were tested on a mechanical testing machine, and the resulting stress-versus-stretch responses were studied. The fiber volume fraction (FVF), fiber spacing, and orientations were varied to estimate the changes in the mechanical responses. The mechanical behavior of the soft composites was characterized using hyperelastic material models such as Mooney-Rivlin's, Humphrey's, and Veronda-Westmann's model and also compared with the anisotropic mechanical behavior of the human skin, pelvic tissues, and brain tissues. This work lays the foundation for the experimental modelling of tissue anisotropy, which combined with microscopic studies on tissues can lead to refinements in the simulation of localized fiber distribution and orientations, and enable the development of biofidelic anisotropic tissue phantom materials for various tissue engineering and testing applications.

Tissue Anisotropy Modeling Using Soft Composite Materials

PubMed Central

Callaway, Christian

2018-01-01

Soft tissues in general exhibit anisotropic mechanical behavior, which varies in three dimensions based on the location of the tissue in the body. In the past, there have been few attempts to numerically model tissue anisotropy using composite-based formulations (involving fibers embedded within a matrix material). However, so far, tissue anisotropy has not been modeled experimentally. In the current work, novel elastomer-based soft composite materials were developed in the form of experimental test coupons, to model the macroscopic anisotropy in tissue mechanical properties. A soft elastomer matrix was fabricated, and fibers made of a stiffer elastomer material were embedded within the matrix material to generate the test coupons. The coupons were tested on a mechanical testing machine, and the resulting stress-versus-stretch responses were studied. The fiber volume fraction (FVF), fiber spacing, and orientations were varied to estimate the changes in the mechanical responses. The mechanical behavior of the soft composites was characterized using hyperelastic material models such as Mooney-Rivlin's, Humphrey's, and Veronda-Westmann's model and also compared with the anisotropic mechanical behavior of the human skin, pelvic tissues, and brain tissues. This work lays the foundation for the experimental modelling of tissue anisotropy, which combined with microscopic studies on tissues can lead to refinements in the simulation of localized fiber distribution and orientations, and enable the development of biofidelic anisotropic tissue phantom materials for various tissue engineering and testing applications. PMID:29853996

Process compensated resonance testing modeling for damage evolution and uncertainty quantification

NASA Astrophysics Data System (ADS)

Biedermann, Eric; Heffernan, Julieanne; Mayes, Alexander; Gatewood, Garrett; Jauriqui, Leanne; Goodlet, Brent; Pollock, Tresa; Torbet, Chris; Aldrin, John C.; Mazdiyasni, Siamack

2017-02-01

Process Compensated Resonance Testing (PCRT) is a nondestructive evaluation (NDE) method based on the fundamentals of Resonant Ultrasound Spectroscopy (RUS). PCRT is used for material characterization, defect detection, process control and life monitoring of critical gas turbine engine and aircraft components. Forward modeling and model inversion for PCRT have the potential to greatly increase the method's material characterization capability while reducing its dependence on compiling a large population of physical resonance measurements. This paper presents progress on forward modeling studies for damage mechanisms and defects in common to structural materials for gas turbine engines. Finite element method (FEM) models of single crystal (SX) Ni-based superalloy Mar-M247 dog bones and Ti-6Al-4V cylindrical bars were created, and FEM modal analyses calculated the resonance frequencies for the samples in their baseline condition. Then the frequency effects of superalloy creep (high-temperature plastic deformation) and macroscopic texture (preferred crystallographic orientation of grains detrimental to fatigue properties) were evaluated. A PCRT sorting module for creep damage in Mar-M247 was trained with a virtual database made entirely of modeled design points. The sorting module demonstrated successful discrimination of design points with as little as 1% creep strain in the gauge section from a population of acceptable design points with a range of material and geometric variation. The resonance frequency effects of macro-scale texture in Ti-6Al-4V were quantified with forward models of cylinder samples. FEM-based model inversion was demonstrated for Mar-M247 bulk material properties and variations in crystallographic orientation. PCRT uncertainty quantification (UQ) was performed using Monte Carlo studies for Mar-M247 that quantified the overall uncertainty in resonance frequencies resulting from coupled variation in geometry, material properties, crystallographic orientation and creep damage. A model calibration process was also developed that evaluates inversion fitting to differences from a designated reference sample rather than absolute property values, yielding a reduction in fit error.

Interplay between spherical confinement and particle shape on the self-assembly of rounded cubes.

PubMed

Wang, Da; Hermes, Michiel; Kotni, Ramakrishna; Wu, Yaoting; Tasios, Nikos; Liu, Yang; de Nijs, Bart; van der Wee, Ernest B; Murray, Christopher B; Dijkstra, Marjolein; van Blaaderen, Alfons

2018-06-08

Self-assembly of nanoparticles (NPs) inside drying emulsion droplets provides a general strategy for hierarchical structuring of matter at different length scales. The local orientation of neighboring crystalline NPs can be crucial to optimize for instance the optical and electronic properties of the self-assembled superstructures. By integrating experiments and computer simulations, we demonstrate that the orientational correlations of cubic NPs inside drying emulsion droplets are significantly determined by their flat faces. We analyze the rich interplay of positional and orientational order as the particle shape changes from a sharp cube to a rounded cube. Sharp cubes strongly align to form simple-cubic superstructures whereas rounded cubes assemble into icosahedral clusters with additionally strong local orientational correlations. This demonstrates that the interplay between packing, confinement and shape can be utilized to develop new materials with novel properties.

Epitaxial Growth of Oriented Metalloporphyrin Network Thin Film for Improved Selectivity of Volatile Organic Compounds.

PubMed

Li, De-Jing; Gu, Zhi-Gang; Vohra, Ismail; Kang, Yao; Zhu, Yong-Sheng; Zhang, Jian

2017-05-01

This study reports an oriented and homogenous cobalt-metalloporphyrin network (PIZA-1) thin film prepared by liquid phase epitaxial (LPE) method. The thickness of the obtained thin films can be well controlled, and their photocurrent properties can also be tuned by LPE cycles or the introduction of conductive guest molecules (tetracyanoquinodimethane and C 60 ) into the PIZA-1 pores. The study of quartz crystal microbalance adsorption confirms that the PIZA-1 thin film with [110]-orientation presents much higher selectivity of benzene over toluene and p-xylene than that of the PIZA-1 powder with mixed orientations. These results reveal that the selective adsorption of volatile organic compounds highly depends on the growth orientations of porphyrin-based metal-organic framework thin films. Furthermore, the work will provide a new perspective for developing important semiconductive sensing materials with improved selectivity of guest compounds. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Research on Extrusion of Rubber Composites Reinforced by Short Fibers Orientation Based on FEA

NASA Astrophysics Data System (ADS)

Zhang, Dewei; Wang, Chuansheng; Shen, Bo; Li, Shaoming; Bian, Huiguang

2018-06-01

In recent years, rubber composites reinforced by short fibers has been researched deeply, because of its good performances such as higher wear resistance, higher cut resistance and so on. Some research results indicated that if short fibers get orientation in rubber composites, the performances of rubber products could be promoted greatly. But how to make short fibers get orientation in rubber matrix during extrusion is still a real problem. And there are many parameters affect the short fibers orientation. So, in this paper, the effects of die structure including expansion-die and dam-expansion-die on extrusion flow field of short fiber and rubber composite material during extrusion process has been researched by Polyflow. And the FEA results about the pressure field, velocity field and the velocity vector of the rubber composites flow field indicate that, comparing with expansion-die and the dam-expansion-die, the latter one is better for the extrusion process of rubber composites and making short fibers get radial orientation in rubber matrix.

Micromechanical models for the stiffness and strength of UHMWPE macrofibrils

NASA Astrophysics Data System (ADS)

Dong, Hai; Wang, Zheliang; O'Connor, Thomas C.; Azoug, Aurelie; Robbins, Mark O.; Nguyen, Thao D.

2018-07-01

Ultrahigh molecular weight polyethylene (UHMWPE) fibers have a complex hierarchical structure that at the micron-scale is composed of oriented chain crystals, lamellar crystals, and amorphous domains organized into macrofibrils. We developed a computational micromechanical modeling study of the effects of the morphological structure and constituent material properties on the deformation mechanisms, stiffness and strength of the UHMWPE macrofibrils. Specifically, we developed four representative volume elements, which differed in the arrangement and orientation of the lamellar crystals, to describe the various macrofibrillar microstructures observed in recent experiments. The stiffness and strength of the crystals were determined from molecular dynamic simulations of a pure PE crystal. A finite deformation crystal plasticity model was used to describe the crystals and an isotropic viscoplastic model was used for the amorphous phase. The results show that yielding in UHMWPE macrofibrils under axial tension is dominated by the slip in the oriented crystals, while yielding under transverse compression and shear is dominated by slips in both the oriented and lamellar crystals. The results also show that the axial modulus and strength are mainly determined by the volume fraction of the oriented crystals and are insensitive to the arrangements of the lamellar crystals when the modulus of the amorphous phase is significantly smaller than that of the crystals. In contrast, the arrangement and size of the lamellar crystals have a significant effect on the stiffness and strength under transverse compression and shear. These findings can provide a guide for new materials and processing design to improve the properties of UHMWPE fibers by controlling the macrofibrillar morphologies.

Perpendicular Orientation Control without Interfacial Treatment of RAFT-Synthesized High-χ Block Copolymer Thin Films with Sub-10 nm Features Prepared via Thermal Annealing.

PubMed

Nakatani, Ryuichi; Takano, Hiroki; Chandra, Alvin; Yoshimura, Yasunari; Wang, Lei; Suzuki, Yoshinori; Tanaka, Yuki; Maeda, Rina; Kihara, Naoko; Minegishi, Shinya; Miyagi, Ken; Kasahara, Yuusuke; Sato, Hironobu; Seino, Yuriko; Azuma, Tsukasa; Yokoyama, Hideaki; Ober, Christopher K; Hayakawa, Teruaki

2017-09-20

In this study, a series of perpendicular lamellae-forming poly(polyhedral oligomeric silsesquioxane methacrylate-block-2,2,2-trifluoroethyl methacrylate)s (PMAPOSS-b-PTFEMAs) was developed based on the bottom-up concept of creating a simple yet effective material by tailoring the chemical properties and molecular composition of the material. The use of silicon (Si)-containing hybrid high-χ block copolymers (BCPs) provides easy access to sub-10 nm feature sizes. However, as the surface free energies (SFEs) of Si-containing polymers are typically vastly lower than organic polymers, this tends to result in the selective segregation of the inorganic block onto the air interface and increased difficulty in controlling the BCP orientation in thin films. Therefore, by balancing the SFEs between the organic and inorganic blocks through the use of poly(2,2,2-trifluoroethyl methacrylate) (PTFEMA) on the organic block, a polymer with an SFE similar to Si-containing polymers, orientation control of the BCP domains in thin films becomes much simpler. Herein, perpendicularly oriented BCP thin films with a χ eff value of 0.45 were fabricated using simple spin-coating and thermal annealing processes under ambient conditions. The thin films displayed a minimum domain size of L 0 = 11 nm, as observed via atomic force microscopy (AFM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Furthermore, directed self-assembly (DSA) of the BCP on a topographically prepatterned substrate using the grapho-epitaxy method was used to successfully obtain perpendicularly oriented lamellae with a half pitch size of ca. 8 nm.

Dentinal tubules revealed with X-ray tensor tomography.

PubMed

Jud, Christoph; Schaff, Florian; Zanette, Irene; Wolf, Johannes; Fehringer, Andreas; Pfeiffer, Franz

2016-09-01

Dentin is a mineralized material making up most of the tooth bulk. A system of microtubules, so called dentinal tubules, transverses it radially from the pulp chamber to the outside. This highly oriented structure leads to anisotropic mechanical properties directly connected to the tubules orientation and density: the ultimate tensile strength as well as the fracture toughness and the shear strength are largest perpendicular to dentinal tubules. Consequently, the fatigue strength depends on the direction of dentinal tubules, too. However, none of the existing techniques used to investigate teeth provide access to orientation and density of dentinal tubules for an entire specimen in a non-destructive way. In this paper, we measure a third molar human tooth both with conventional micro-CT and X-ray tensor tomography (XTT). While the achievable resolution in micro-CT is too low to directly resolve the dentinal tubules, we provide strong evidence that the direction and density of dentinal tubules can be indirectly measured by XTT, which exploits small-angle X-ray scattering to retrieve a 3D map of scattering tensors. We show that the mean directions of scattering structures correlate to the orientation of dentinal tubules and that the mean effective scattering strength provides an estimation of the relative density of dentinal tubules. Thus, this method could be applied to investigate the connection between tubule orientation and fatigue or tensile properties of teeth for a full sample without cutting one, non-representative peace of tooth out of the full sample. Copyright © 2016 The Academy of Dental Materials. All rights reserved.

Retaining {1 0 0} texture from initial columnar grains in 6.5 wt% Si electrical steels

NASA Astrophysics Data System (ADS)

Liang, Ruiyang; Yang, Ping; Mao, Weimin

2017-11-01

6.5 wt% Si electrical steel is a superior soft magnetic material with excellent magnetic properties which highly depends on texture. In this study, based on the heredity of 〈0 0 1〉 orientation in columnar grains, columnar grains are used as the initial material to prepare non-oriented 6.5 wt% Si electrical steel with excellent magnetic properties. EBSD and XRD techniques are adopted to explore the structure and texture evolution during hot rolling, warm rolling, cold rolling and annealing. The results show that, due to the heredity of "structure and texture" from the initial strong {1 0 0} columnar grains, annealed sheet with {1 0 0}〈0 0 1〉 texture had better magnetic properties, which can be used as non-oriented high-silicon electrical steel. Both preferred cube grain nucleation in deformed {1 1 3}〈3 6 1〉 grains in subsurface and coarse {1 0 0}〈0 0 1〉 deformed grains in center layer show the effect of initial columnar grains with {1 0 0} texture.

Elucidation of perovskite film micro-orientations using two-photon total internal reflectance fluorescence microscopy

DOE PAGES

Watson, Brianna R.; Yang, Bin; Xiao, Kai; ...

2015-07-29

The emergence of efficient hybrid organic-inorganic perovskite photovoltaic materials has caused the rapid development of a variety of preparation and processing techniques designed to maximize their performance. As processing methods continue to emerge, it is important to understand how the optical properties of these materials are affected on a microscopic scale. Here polarization resolved two-photon total internal reflectance microscopy (TIRFM) was used to probe changes in transition dipole moment orientation as a function of thermal annealing time in hybrid organic-inorganic lead iodide based perovskite (CH 3NH 3PbI 3) thin films on glass. These results show that as thermal annealing timemore » is increased the distribution of transition moments pointing out-of-plane decreases in favor of forming areas with increased in-plane orientations. As a result, it was also shown through the axial sensitivity of TIRFM that the surface topography is manifested in the signal intensity and can be used to survey aspects of morphology in coincidence with the optical properties of these films.« less

From Bench Top to Market: Growth of Multi-Walled Carbon Nanotubes by Injection CVD Using Fe Organometallics - Production of a Commercial Reactor

NASA Technical Reports Server (NTRS)

Rowsell, J.; Hepp, A. F.; Harris, J. D.; Raffaelle, R. P.; Cowen, J. C.; Scheiman, D. A.; Flood, D. M.; Flood, D. J.

2009-01-01

Preferential oriented multiwalled carbon nanotubes were prepared by the injection chemical vapor deposition (CVD) method using either cyclopentadienyliron dicarbonyl dimer or cyclooctatetraene iron tricarbonyl as the iron catalyst source. The catalyst precursors were dissolved in toluene as the carrier solvent for the injections. The concentration of the catalyst was found to influence both the growth (i.e., MWNT orientation) of the nanotubes, as well as the amount of iron in the deposited material. As deposited, the multiwalled carbon nanotubes contained as little as 2.8% iron by weight. The material was deposited onto tantalum foil and fused silica substrates. The nanotubes were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and thermogravimetric analysis. This synthetic route provides a simple and scalable method to deposit MWNTs with a low defect density, low metal content and a preferred orientation. Subsequently, a small start-up was founded to commercialize the deposition equipment. The contrast between the research and entrepreneurial environments will be discussed.

Broadband dielectric characterization of sapphire/TiOx/Ba₀.₃Sr₀.₇TiO₃ (111)-oriented thin films for the realization of a tunable interdigitated capacitor.

PubMed

Ghalem, Areski; Ponchel, Freddy; Remiens, Denis; Legier, Jean-Francois; Lasri, Tuami

2013-05-01

A complete microwave characterization up to 67 GHz using specific coplanar waveguides was performed to determine the dielectric properties (permittivity, losses, and tunability) of sapphire/TiOx/Ba0.3Sr0.7TiO3 (BST) (111)-oriented thin films. To that end, BaxSr1-xTiO3 thin films were deposited by RF magnetron sputtering on sapphire (0001) substrate. To control the preferred (111) orientation, a TiOx buffer layer was deposited on sapphire. According to the detailed knowledge of the material properties, it has been possible to conceive, fabricate, and test interdigitated capacitors, the basic element for future microwave tunable applications. Retention of capacitive behavior up to 67 GHz and a tunability of 32% at 67 GHz at an applied voltage of 30 V (150 kV/cm) were observed. The Q-factor remains greater than 30 over the entire frequency band. The possibility of a complete characterization of the material for the realization of high-performance interdigitated capacitors opens the door to microwave device fabrication.

Validity of Learning Module Natural Sciences Oriented Constructivism with the Contain of Character Education for Students of Class VIII at Yunior Hight School

NASA Astrophysics Data System (ADS)

Oktarina, K.; Lufri, L.; Chatri, M.

2018-04-01

Referring to primary data collected through observation and interview to natural science teachers and some students, it is found that there is no natural science teaching materials in the form of learning modules that can make learners learn independently, build their own knowledge, and construct good character in themselves. In order to address this problem, then it is developed natural science learning module oriented to constructivism with the contain of character education. The purpose of this study is to reconstruct valid module of natural science learning materials. This type of research is a development research using the Plomp model. The development phase of the Plomp model consists of 3 stages, namely 1) preliminary research phase, 2) development or prototyping phase, and 3) assessment phase. The result of the study shows that natural science learning module oriented to constructivism with the contain of character education for students class VIII of Yunior High School 11 Sungai Penuh is valid. In future work, practicality and effectiveness will be investigated.

Correlation of Thermally Induced Pores with Microstructural Features Using High Energy X-rays

NASA Astrophysics Data System (ADS)

Menasche, David B.; Shade, Paul A.; Lind, Jonathan; Li, Shiu Fai; Bernier, Joel V.; Kenesei, Peter; Schuren, Jay C.; Suter, Robert M.

2016-11-01

Combined application of a near-field High Energy Diffraction Microscopy measurement of crystal lattice orientation fields and a tomographic measurement of pore distributions in a sintered nickel-based superalloy sample allows pore locations to be correlated with microstructural features. Measurements were carried out at the Advanced Photon Source beamline 1-ID using an X-ray energy of 65 keV for each of the measurement modes. The nickel superalloy sample was prepared in such a way as to generate significant thermally induced porosity. A three-dimensionally resolved orientation map is directly overlaid with the tomographically determined pore map through a careful registration procedure. The data are shown to reliably reproduce the expected correlations between specific microstructural features (triple lines and quadruple nodes) and pore positions. With the statistics afforded by the 3D data set, we conclude that within statistical limits, pore formation does not depend on the relative orientations of the grains. The experimental procedures and analysis tools illustrated are being applied to a variety of materials problems in which local heterogeneities can affect materials properties.

Soft X-ray Spectromicroscopy of Polymers

NASA Astrophysics Data System (ADS)

Ade, Harald

1997-03-01

The development of Near Edge X-ray Absorption Fine Structure (NEXAFS) microscopy^1 and linear dichroism microscopy^2 over the last few years utilizing the X1-Scanning Transmission X-ray Microscope (X1-STXM) at the National Synchrotron Light Source provides excellent specificity to various functional groups and moieties in organic molecules and polymeric materials at a spatial resolution of 50 nm. This chemical specificity can be utilized to map the distribution of various compounds in a material, or to micro-chemically analyze small sample areas. Examples of applications include the study of various phase-separated polymers (polyurethanes, liquid crystalline polyesters), multicomponent polymer blends, polymer laminates, and other organic materials such as coal^3. Linear dichroism microscopy furthermore explores the polarization dependence of NEXAFS in (partially) oriented materials, and can determine the orientation of specific functional groups. Applications of linear dichroism microscopy have focused so far on determining the relative degree of radial orientation in Kevlar fibers^3. ^1 H. Ade, X. Zhang, S. Cameron, C. Costello, J. Kirz, and S. Williams, Science 258, 972 (1992). ^2 H. Ade and B. Hsiao, Science 262, 1427 (1993). ^3 Acknowledgement: My callaborators are B. Hsiao, S. Subramoney, B. Wood, I. Plotzker, E. Rightor, G. Mitchell, C. Sloop, D.-J. Liu, S.-C. Liu, J. Marti, C. Zimba, A. P. Smith, R. Spontak, R. Fornes, R. Gilbert, C. Cody, A. Hitchcock and S. Urquhart. The X1-STXM is built and maintained by J. Kirz and C. Jacobsen and their groups. Work supported by: NSF Young Investigator Award (DMR-9458060), DuPont Young Professor Grant, and Dow Chemical.

Bridging the gap in 1(st) year dental material curriculum: A 3 year randomized cross over trial.

PubMed

Gali, Sivaranjani; Shetty, Vibha; Murthy, N S; Marimuthu, P

2015-01-01

Case-oriented small group discussions (COSGDs) can help students to correlate and integrate the basic science of dental materials into clinical application. We used COSGDs along with didactic lectures in dental material curriculum and hypothesized that case-oriented group discussions would be more effective than traditional lecture alone in terms of performance of students, student perception on the above two teaching methodologies and the feasibility in classes of 2010, 2011 and 2012. A total of 170 students were taught using both COSGD and didactic lecture in a randomized controlled crossover trial design. Their performance was assessed through multiple-choice questions (MCQs) as part of the formative assessment, and their perception was assessed through Likert scale questionnaire. The mean difference in the scores between case-oriented group discussions with lecture and didactic lecture showed significant difference only in few topics. Around 94-96% of students perceived COSGD with didactic lecture help them understand theory better; 76-92% of students feel more comfortable asking questions in a group discussion; 89-98% of students feel such discussions motivate them and 91-100% of students agree that discussions make the subject interesting in the respective years of 2010, 2011 and 2012. Effectiveness of COSGD in terms of scores through MCQs is comparable to traditional lecture. However, most of the students perceive COSGD help them understand the theory better; co-relate clinically; more motivating and interesting than a traditional lecture. Feasibility in institution needs more time and resources to conduct COSGD within the dental material curriculum.

Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - Second FY 2015 Quarterly Report

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

Nguyen, Ba Nghiep; Fifield, Leonard S.; Kijewski, Seth A.

During the second quarter of FY 2015, the following technical progress has been made toward project milestones: 1) Autodesk reviewed 3D fiber orientation distribution (FOD) comparisons and provided support on improving accuracy. 2) Autodesk reviewed fiber length distribution (FLD) data comparisons and provided suggestions, assisted PNNL in FOD and FLD parameter settings optimization, and advised PNNL on appropriate through thickness thermal conductivity for improved frozen layer effect on FOD predictions. Autodesk also participated in project review meetings including preparations and discussions towards passing the go/no-go decision point. 3) Autodesk implemented an improved FOD inlet profile specification method through the partmore » thickness for 3D meshes and provided an updated ASMI research version to PNNL. 4) The University of Illinois (Prof. C.L. Tucker) provided Autodesk with ideas to improve fiber orientation modeling 5) Purdue University re-measured fiber orientation for the fast-fill 50wt% LCF/PA66 edge-gated plaque, and delivered the fiber orientation data for this plaque at the selected locations (named A, B, and C, Figure 1) to PNNL. Purdue also re-measured fiber orientation for locations A on the fast-fill 30wt% LCF/PP and 50wt% LCF/PA66 center-gated plaques, which exhibited anomalous fiber orientation behavior. 6) Purdue University conducted fiber length measurements and delivered the length data to PNNL for the purge materials (slow-fill 30wt% LCF/PP and 30wt% LCF/PA66 purge materials) and PlastiComp plaques selected on the go/no-go list for fiber length model validation (i.e., slow-fill edge-gated 30wt% LCF/PP and 30wt% LCF/PA66 plaques, Locations A, B, and C). 7) PNNL developed a method to recover intact carbon fibers from LCF/PA66 materials. Isolated fibers were shipped to Purdue for length distribution analysis. 8) PNNL completed ASMI mid-plane analyses for all the PlastiComp plaques defined on the go/no-go list for fiber orientation (FO) model validation and compared the predicted fiber orientations with the measured data provided by Purdue at Locations A, B, and C on these plaques. The 15% accuracy criterion based on evaluation of tensile and bending stiffness was used to assess the accuracy in fiber orientation predictions. 9) PNNL completed ASMI mid-plane analyses for all the PlastiComp plaques defined on the go/no-go list for fiber length distribution (FLD) model validation and compared the predicted length distributions with the measured data provided by Purdue at Locations A, B, and C on these plaques. The 15% accuracy criterion based on evaluation of tensile and bending stiffness was used to assess the accuracy in fiber orientation predictions. 10) PNNL tested the new ASMI version received from Autodesk in March 2015, examined and discussed 3D fiber orientation predictions for PlastiComp plaques. 11) PlastiComp, Inc. (PlastiComp), Toyota Research Institute North America (Toyota) and Magna Exteriors and Interiors Corporation (Magna) participated in discussions with team members on the go/no-go plan. Toyota continued the discussion with Magna on tool modification for molding the complex part in order to achieve the target fiber length in the part.« less

Optimal Location of Piezoelectric Patch on Composite Structure using Viewing Method

NASA Astrophysics Data System (ADS)

Samyal, Rahul; Bagha, Ashok K.

2017-08-01

A useful material which is manufactured by mixing of two or three different materials in homogeneous level is termed as composite material. In now day’s composite materials are used in wide area such as aerospace, automobiles, satellite, bullet proof jackets, rotor blades etc. In this paper modal analysis of composite material, mixture of polyester as matrix and glass as fiber, is carried out by using ABAQUS software. The modal analysis of composite material for fiber orientation 450 is carried out. In this paper by viewing the different mode shapes of the composite material, the optimal location of piezoelectric patch is carried out.

Materialism across the life span: An age-period-cohort analysis.

PubMed

Jaspers, Esther D T; Pieters, Rik G M

2016-09-01

This research examined the development of materialism across the life span. Two initial studies revealed that (a) lay beliefs were that materialism declines with age and (b) previous research findings also implied a modest, negative relationship between age and materialism. Yet, previous research has considered age only as a linear control variable, thereby precluding the possibility of more intricate relationships between age and materialism. Moreover, prior studies have relied on cross-sectional data and thus confound age and cohort effects. To improve on this, the main study used longitudinal data from 8 waves spanning 9 years of over 4,200 individuals (16 to 90 years) to examine age effects on materialism while controlling for cohort and period effects. Using a multivariate multilevel latent growth model, it found that materialism followed a curvilinear trajectory across the life span, with the lowest levels at middle age and higher levels before and after that. Thus, in contrast to lay beliefs, materialism increased in older age. Moreover, age effects on materialism differed markedly between 3 core themes of materialism: acquisition centrality, possession-defined success, and acquisition as the pursuit of happiness. In particular, acquisition centrality and possession-defined success were higher at younger and older age. Independent of these age effects, older birth cohorts were oriented more toward possession-defined success, whereas younger birth cohorts were oriented more toward acquisition centrality. The economic downturn since 2008 led to a decrease in acquisition as the pursuit of happiness and in desires for personal growth, but to an increase in desires for achievement. (PsycINFO Database Record (c) 2016 APA, all rights reserved).